Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/17/13
AREA FORECAST DISCUSSION
NWS TUCSON AZ
200 PM MST SUN SEP 15 2013
.SYNOPSIS...THERE WILL BE ENOUGH MOISTURE FOR ISOLATED TO SCATTERED
THUNDERSTORMS MAINLY EAST OF TUCSON TO START THE WEEK. THE DRIER
WESTERLY FLOW WILL CONTINUE TO DIMINISH MOISTURE THROUGH THE
WEEK...BUT WE MAY HOLD ON TO ENOUGH TO KEEP A FEW MOUNTAIN
THUNDERSTORMS AROUND IN THE AFTERNOONS.
&&
.DISCUSSION...ISOLATED CONVECTION STARTING THIS AFTERNOON BUT
MOISTURE IS GETTING MORE AND MORE MARGINAL. GOES SOUNDER ESTIMATED
PRECIPITABLE WATER DOWN TO AROUND .95 TO 1 INCH IN A MODEST BUT
DRIER WESTERLY FLOW AT MOST LEVELS. EXCEPTION IS LOWER LEVELS WITH
CONTINUED EASTERLY AND SOUTHEASTERLY COMPONENTS. SURFACE DEWPTS DOWN
ABOUT 2 TO 4 DEGREES OVERALL THE PAST 24 HOURS FROM TUCSON
WESTWARD...BUT LATEST HRRR CONTINUES NEAR SURFACE STREAMLINES FROM
NEW MEXICO INTO EASTERN ZONES INTO EARLY MONDAY. THIS WILL PROBABLY
HELP KEEP ISOLATED TO LOW END SCATTERED CONVECTION GOING MAINLY EAST
OF TUCSON WITH AN EMPHASIS ON THE MOUNTAINS.
LATEST NAMDNG5 CONTINUES EASTERLY SURFACE WINDS INTO TUESDAY AS FAR
WEST AS TUCSON...UP TO BREEZY LEVELS AT TIMES. THIS COULD CAUSE
PROBLEMS WITH OVERNIGHT LOWS IN A COUPLE OF LOCATIONS WITH THE
POTENTIAL FOR THE BOUNDARY LAYER TO REMAIN MIXED AND KEEP
TEMPERATURES UP A BIT. AT THAT POINT THE LOWER LEVEL FLOW STARTS TO
STACK MORE NEATLY AND ADDITIONAL DRYING WILL PROBABLY SEE EVEN
EASTERN MOUNTAINS LOSING THUNDERSTORMS WITH A BELOW 10 PERCENT
FORECAST AREA WIDE BY WEDNESDAY.
SOME MOISTURE PUSH FROM THE TROPICS INTO SONORA AND CHIHUAHUA IS
EXPECTED LATER IN THE WEEK...BUT IS STILL EXPECTED TO HAVE
DIFFICULTY MAKING MUCH PROGRESS FURTHER NORTH WITH THE UNFAVORABLE
WESTERLY FLOW. A WEAK SHORTWAVE RIDGE COULD ALLOW ENOUGH OF A BREAK
IN THE FLOW FOR AREAS MAINLY NEAR THE INTERNATIONAL BORDER TO SEE
ISOLATED CONVECTION AGAIN LATER IN THE WEEK.
&&
.AVIATION...VALID THRU 16/21Z.
WEST OF KTUS MOSTLY CLEAR. KTUS EWD/SWD ISOLD-SCT -TSRA/-SHRA THIS
AFTERNOON AND THIS EVENING...AND A FEW -TSRA/-SHRA MAINLY NEAR THE
NEW MEXICO BORDER LATE TONIGHT. OTHERWISE...FEW-BKN CLOUDS
MAINLY AT 6-10K FT AGL THIS AFTERNOON AND THIS EVENING...AND FEW-SCT
CLOUDS MOSTLY ABOVE 10K FT AGL LATE TONIGHT. SURFACE WIND GENERALLY
OUT OF THE EAST AT 5-15KTS AND GUSTY AT TIMES INTO MONDAY. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...EXPECT ISOLATED TO SCATTERED THUNDERSTORMS MAINLY
EAST OF TUCSON THROUGH TUESDAY. SOME DRYING THROUGH THE WEEK BUT WE
MAY HOLD ON TO ENOUGH MOISTURE FOR ISOLATED MOUNTAIN
THUNDERSTORMS...ESPECIALLY NEAR THE INTERNATIONAL BORDER. GUSTY EAST
WINDS AT TIMES THROUGH TUESDAY. OTHERWISE...DAYTIME TEMPERATURES
WILL BE A FEW DEGREES ABOVE NORMAL THIS WEEK.
&&
.HYDROLOGY...THE SAN FRANCISCO RIVER AT CLIFTON CRESTED AT 24.1 FEET
AT 1045 AM MST...BUT HAS FALLEN TO 20 FEET AS OF 130 PM MST. THE
RIVER IS EXPECTED TO CONTINUE TO GRADUALLY FALL THIS AFTERNOON.
THE FLOWS FROM THE SAN FRANCISCO WILL MOVE INTO THE GILA RIVER LATER
TODAY WHICH IS EXPECTED TO REMAIN ABOVE BANKFULL AT SOLOMON BUT
BELOW MINOR FLOOD STAGE. THIS WOULD STILL HAVE THE POTENTIAL TO
FLOOD LOW LYING AGRICULTURAL AREAS NEAR THE RIVER.
RISES ON THE GILA RIVER IN NEW MEXICO WILL CONTINUE TO MAKE THEIR
WAY DOWNSTREAM INTO ARIZONA TODAY. THE GILA RIVER AT RED ROCK NEW
MEXICO CRESTED JUST BEFORE 10 AM MST THIS MORNING. WHILE RISES WILL
OCCUR DURING THE EVENING HOURS ON THE GILA RIVER AT DUNCAN AND SOUTH
OF CLIFTON...THE RIVER SHOULD REMAIN BELOW BANKFULL.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
FLOOD WARNING IN EFFECT TODAY FOR THE SAN FRANCISCO
RIVER AT CLIFTON.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
MEYER/DROZD
AREA FORECAST DISCUSSION
NWS SAN JOAQUIN VALLEY - HANFORD CA
258 AM PDT SUN SEP 15 2013
.SYNOPSIS...
DRY CONDITIONS WITH NEAR NORMAL TEMPERATURES FOR THE NEXT FEW DAYS.
&&
.DISCUSSION...
UPPER LOW CENTER IS FINALLY MOVING OUT OF NV AND HAVE REMOVED ANY
CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS THE SIERRA FOR THIS
AFTERNOON AS DRIER CONDITIONS ARE EXPECTED. THE UPPER RIDGE OVER
THE REGION WILL SLOWLY SLIDE EAST AS A LOW PRESSURE CENTER OFF THE
NORCAL COAST WILL LIFT NE INTO THE PAC NW THIS EVENING. AN UPPER
LEVEL TROUGH OF LOW PRESSURE WILL SKIRT THE REGION ACCORDING TO
THE RUC MODEL LATER TODAY. INCREASING WINDS OVER THE WEST SIDE OF
THE SJV AND THROUGH THE COTTONWOOD AND PACHECO PASS ARE A CONCERN
BUT ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA. A BIT OF A
COOL DOWN IS EXPECTED FOR MONDAYS HIGHS AS THE MARINE COOLED AIR
WILL HAVE AN INFLUENCE ON VALLEY TEMPS.
ZONAL FLOW SETS UP MONDAY AND OPENS THE DOORS FOR CONTINUED SEASONAL
TEMPS AS ANOTHER SHORT WAVE MOVES THROUGH ON TUESDAY WITH RE-ENFORCING
COOL TEMPS FOR TUESDAY AND WED. SOME MINOR UPPER LEVEL SHORTWAVE
RIDGING IS EXPECTED ON THURSDAY AND FRIDAY IN ADVANCE OF A STRONG
UPPER LEVEL TROUGH OF OF LOW PRESSURE THAT IS EXPECTED TO SWEEP
THROUGH THE REGION ON FRI NIGHT. THE GFS IS WEAKER WITH THE SYSTEM
AND H500 FALLS ARE NOT AS DRASTIC AS PREVIOUS RUNS. WE HAVE BUMPED
UP TEMPS A FEW DEGREES OVER THE WEEKEND AS THE GUIDANCE IS LEANING
MORE TOWARDS CLIMO IN THE EXTENDED...HOWEVER WE ARE STILL EXPECTING
BELOW TEMPERATURES NEXT WEEKEND.
&&
.AVIATION...
MVFR CONDITIONS DUE TO SMOKE WILL PERSIST NEAR YOSEMITE NATIONAL
PARK...OTHERWISE VFR CONDITIONS WILL PREVAIL ELSEWHERE IN THE
CENTRAL CALIFORNIA INTERIOR DURING THE NEXT 24 HOURS.
&&
.AIR QUALITY ISSUES...
SAN JOAQUIN VALLEY...NONE.
TUOLUMNE COUNTY...AIR QUALITY ALERT THROUGH MONDAY SEPTEMBER 16TH.
SEE SFOAQAHNX.
FOR ADDITIONAL INFORMATION...CALL THE TUOLUMNE COUNTY AIR DISTRICT
OFFICE AT 209.533.5693
&&
.CERTAINTY...
THE LEVEL OF CERTAINTY FOR DAYS 1 AND 2 IS HIGH.
THE LEVEL OF CERTAINTY FOR DAYS 3 THROUGH 7 IS HIGH.
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 09-15 104:1983 74:1982 72:1938 45:1970
KFAT 09-16 105:1937 70:1908 73:1934 49:1955
KFAT 09-17 105:1979 73:1950 74:1984 48:1965
KBFL 09-15 106:1979 75:1959 77:1979 40:1915
KBFL 09-16 109:1929 74:1959 77:1971 42:1915
KBFL 09-17 108:1913 74:1993 76:1979 45:1915
&&
.HNX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
PUBLIC...JDB
AVN/FW...DCH
SYNOPSIS...JDB
WEATHER.GOV/HANFORD
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
902 PM MDT MON SEP 16 2013
.UPDATE...
ISSUED AT 901 PM MDT MON SEP 16 2013
A FEW SHOWERS AND THUNDERSTORMS CONTINUE TO PERSIST OVER THE UINTA
MTNS IN NORTHEAST UTAH THIS EVENING...AND ADJUSTED THE GRIDDED
FORECAST ACCORDINGLY. A FAIR AMOUNT OF LIGHTNING INDICATED WITH
SOME OF THESE THUNDERSTORMS. ELSEWHERE ACROSS THE FORECAST
AREA...SHOWERS HAVE DIED DOWN WITH THE LOSS OF SOLAR HEATING.
PRECIPITABLE WATER OF 0.64 INCH ON THIS EVENING/S GJT SOUNDING WAS
DOWN CONSIDERABLY FROM THE 0.94 INCH MEASURED THIS MORNING. A
QUICK LOOK AT THE 00Z NAM AND 00Z RAP MODELS SHOW A WEAK
DISTURBANCE CROSSING THE SOUTH LATER TONIGHT...AND THE CURRENT
FORECAST MAINTAINS MENTION OF AN ISOLATED SHOWER OR STORM POSSIBLE
OVER THE SAN JUAN MTNS AFTER MIDNIGHT.
&&
.SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT)
ISSUED AT 356 PM MDT MON SEP 16 2013
LOCAL PROFILERS AND WATER VAPOR IMAGERY SHOWING THE TROF THAT HAS
BEEN LINGERING IN THE WEST FINALLY PUSHING ONTO THE PLAINS THIS
AFTERNOON. WEAKER UPSTREAM WAVE IS MOVING IN BEHIND A TRANSITORY
RIDGE IN NORTHERN UTAH AND PROVIDING A BIT MORE FOCUS FOR STORMS IN
OUR WESTERN CWA...WITH HEATING DRIVING ISOLATED CONVECTION
ELSEWHERE. A DIP IN THE WESTERLIES IS MOVING ONTO THE WEST COAST
THIS AFTERNOON WHICH WILL BE DRIVING A SERIES OF STRONGER OPEN OUT
OF THE EASTERN PACIFIC BEGINNING TONIGHT.
SOUNDINGS SHOW SOME DRIER AIR MOVING INTO THE LOWER LAYERS OF THE
PROFILE BUT MOISTURE STILL HANGING AROUND 600-500MB KEEPING PWATS
ABOVE NORMAL. GOES DERIVED TPW VERIFIES THE MOISTURE HANGING AROUND
THE VEGAS/WESTERN GREAT BASIN AREA AND UPSTREAM OFF THE CALIFORNIA
COAST ASSOCIATED WITH THE WESTERN TROF. THETA SURFACES NEAR 315-320K
SHOW THE FLOW TURNING SOUTHWESTERLY AND INCREASING LATE TONIGHT INTO
TUESDAY AND DRAWING MOISTURE BACK INTO OUR CWA. PIECES OF THE UPPER
JET COMBINE WITH INCREASING LARGE SCALE ASCENT BY THE AFTERNOON
WHICH SHOULD BRING AN UPTICK TO THE CONVECTION. THE STORMS LOOK TO
LINGER THROUGH THE OVERNIGHT HOURS AS THE JET SLOWLY SAGS SOUTHWARD
AND ASCENT INCREASES. TEMPERATURES SHOULD BE MAKING A REBOUND TO
ABOVE NORMAL BY TOMORROW BEFORE A WEAK FRONT PASSES THROUGH THE MID
WEEK.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 356 PM MDT MON SEP 16 2013
A CHANGE IN PATTERN FROM THE STAGNANT MONSOON FLOW TO PROGRESSIVE
WESTERLIES OCCURS THIS WEEK...UNOFFICIALLY ENDING THE MONSOON
SEASON.
WEDNESDAY A PACIFIC TROUGH WORKS THROUGH THE NORTHERN ROCKIES. A
WARM SW GRADIENT WIND WILL MIX DOWN IN THE AFTERNOON FOR BREEZY
WARM CONDITIONS. RESIDUAL MOISTURE IS SUFFICIENT FOR SCATTERED
MAINLY MOUNTAIN SHOWERS AND STORMS. THE ASSOCIATED COOL AND
DRY FRONT PUSHES INTO NE UTAH IN THE AFTERNOON PUSHES THROUGH THE
NORTHERN AND CENTRAL ZONES BECOMING STRETCHED WEST TO EAST
SOMEWHERE NEAR THE HIGHWAY 50 LINE BY THURSDAY MORNING. THIS WILL
USHER IN A DRIER AND COOLER AIR MASS FOR THURSDAY. TEMPERATURES
ACROSS PORTIONS OF NW COLORADO WILL FLIRT WITH THE FREEZING.
TEMPERATURES WILL RECOVER ON FRIDAY INTO SATURDAY TO NEAR NORMAL.
THEN NEXT PACIFIC TROUGH IS CURRENTLY TIMED TO PASS LATE SUNDAY...
WITH ANOTHER TROUGH LATER NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 356 PM MDT MON SEP 16 2013
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS
THE WESTERN COLORADO MOUNTAINS AND OVER THE NORTHEAST UTAH
MOUNTAINS AND BASINS THIS EVENING. A FEW MOUNTAIN OBSCURATIONS
WILL RESULT FROM THE PRECIPITATION AND CLOUDINESS BUT VFR
CONDITIONS SHOULD PREVAIL AT THE FORECAST TERMINALS. THE MAIN
CONCERN WILL BE GUSTY WINDS NEAR SHOWERS AS LOWER LAYERS OF THE
ATMOSPHERE HAVE DRIED OUT AND LESSENED THE THREAT OF HEAVY
RAINFALL IMPACTING FLIGHT OPERATIONS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...JAD
SHORT TERM...15
LONG TERM...JOE
AVIATION...15
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1206 PM MDT SUN SEP 15 2013
.UPDATE...
&&
.SHORT TERM...VERY HEAVY RAIN HAS DEVELOPED OVER THE FOOTHILLS AND
ADJACENT PLAINS OVER THE PAST SEVERAL HOURS. RAINFALL RATES ARE
EVEN HIGHER THAN EXPECTED WITH RATES NOW EXCEEDING ONE INCH IN
LESS THAN AN HOUR OVER NORTHERN PORTIONS OF THE DENVER
AREA...INCLUDING BROOMFIELD...ADAMS...AND JEFFERSON COUNTIES.
EXPECT THESE CONDITIONS TO CONTINUE FOR THE REST OF THE AFTERNOON.
AGAIN ANOTHER VERY DANGEROUS SITUATION WITH MULTIPLE FLASH FLOOD
AND FLOOD WARNINGS ONGOING FOR THE AREA. RAIN IS MORE SCATTERED IN
COVERAGE FURTHER EAST ON THE PLAINS SO EXPECTING A LOWER IMPACT OF
THE CURRENT RAINFALL SITUATION.
.HYDROLOGY...CURRENT FLASH FLOOD WARNINGS OUT FOR FIRE BURN AREAS
AND OTHER LOCATIONS RECEIVING VERY HEAVY RAIN. HIGHER RAINFALL
RATES HAVE AGAIN DEVELOPED WITH RATES OF ONE INCH IN 30 MINUTES OR
LESS IN THE HEAVIEST RAIN. DANGEROUS SITUATION DEVELOPING WITH
POTENTIAL FOR ENHANCED FLOODING AND CONTINUES RIVER AND STREAM
RISES EXPECTED. ONGOING AREAL FLOOD WARNINGS AND RIVER FLOOD
WARNINGS FOR MUCH OF THE AREA NORTH AND NORTHEAST OF DENVER.
&&
.PREV DISCUSSION... /ISSUED 925 AM MDT SUN SEP 15 2013/
UPDATE...
SHORT TERM...RAIN SHOWERS HAVE BEEN RAPIDLY DEVELOPING OVER THE
FOOTHILLS AND PLAINS DURING THE PAST SEVERAL HOURS. PLATTEVILLE
PROFILER SHOWING WEAK UPSLOPE FLOW FROM THE NORTHEAST HAS BEEN
DEEPENING OVER THE PAST SEVERAL HOURS TO MOUNTAIN TOP LEVEL. THE
WEAK FRONTAL BOUNDARY IS FINALLY BEGINNING TO PUSH SOUTH AND
SOUTHWEST AND JUST MOVING INTO THE FRONT RANGE AREA. FORECASTS
LOOK IN GOOD SHAPE FOR NOW.
&&
.AVIATION...CEILINGS LOWERING AND WILL CONTINUE TO LOWER FROM THE
NORTH TO IFR CONDITIONS IN THE NEXT FEW HOURS AS RAIN BEGINS TO
SPREAD ACROSS THE AREA FROM THE NORTH AND NORTHEAST. RAINFALL
SHOULD BE DIMINISHING THIS EVENING WITH IMPROVING CONDITIONS.
POSSIBLE FOG LATER TONIGHT.
.HYDROLOGY...RAIN DEVELOPING AND WILL BECOME MORE WIDESPREAD BY
LATER THIS MORNING OVER THE ENTIRE AREA...WITH HIGHER COVERAGE
OVER THE FOOTHILLS AND ADJACENT PLAINS. CURRENT RAINFALL OVER
LARIMER COUNTY GAUGES SHOWING RAINFALL RATES GENERALLY FROM .20 TO
.50 OF AN INCH PER HOUR WITH THE HEAVIER SHOWERS. JUST ISSUED AN
AREAL FLOOD WARNING FOR MUCH OF THE FRONT RANGE FOOTHILLS...AND
ADJACENT PLAINS AND STRETCHING NORTHEAST TO COVER AREAS ALONG THE
SOUTH PLATTE UP THROUGH JULESBURG AND AREAS ALONG THE CACHE LA
POUDRE. STILL COULD SEE 1 TO 2 INCHES OF ADDITIONAL RAINFALL
THROUGH THIS EVENING ESPECIALLY IN THE FOOTHILLS.
.PREV DISCUSSION... /ISSUED 338 AM MDT SUN SEP 15 2013/
SHORT TERM...REMNANTS OF WK UPPER LEVEL TROUGH WILL SHEAR ACROSS THE
AREA THRU TONIGHT WITH SOME MINOR MID LVL ASCENT. MEANWHILE LOW
LVL WINDS ARE CURRENTLY NLY ALONG THE FNT RANGE BUT ARE FCST TO
BECOME MORE NELY LATER THIS MORNING INTO THE AFTN HOURS BEHIND A
COOL FNT. THIS SHOULD ALLOW FOR INCREASING PCPN IN THE NRN
FOOTHILLS AND MTNS EAST OF THE DIVIDE THIS MORNING WHICH WILL
SPREAD SOUTHWARD THRU THE DAY. AT THIS TIME HIGHEST PCPN AMOUNTS
SHOULD FOCUS IN AND NR THE FOOTHILLS AND IN THE MTNS EAST OF THE
DIVIDE. THE GFS AND HRRR SHOW POTENTIAL RAINFALL AMOUNTS RANGING
FROM 1 TO 2 INCHES OVER THE HIGHER TERRAIN WHILE THE ECMWF KEEPS
THE HEAVIER AMOUNTS FOCUSED EAST OF THE HIGHER TERRAIN OVER THE
FRONT RANGE URBAN CORRIDOR THRU THIS AFTN. AT THIS POINT WILL KEEP
THE HEAVIER AMOUNTS OVER THE HIGHER TERRAIN.
MEANWHILE WITH CONSIDERABLE CLOUD COVER THERE WILL BE LIMITED
INSTABILITY SO THE PCPN WILL BE MORE OF A STRATIFORM EVENT WITH
RAINFALL RATES MAINLY AROUND ONE QUARTER INCH PER HOUR. WILL KEEP
FFA IN PLACE HOWEVER BIGGWST CONCERNS WOULD BE CONSIDERABLE AMOUNT
OF ROCK AND MUD SLIDE ACTIVITY DUE TO EXTREMELY SATURATED GROUND.
HIGH THIS AFTERNOON OVER NERN CO MAY NOT GET MUCH ABV 60 EXCEPT OVER
THE FAR NERN CORNER WHERE HIGHS MAY GET CLOSE TO 70.
FOR TONIGHT THERE WILL BE SOME LINGERING RAIN THEU EVENING WHICH
WILL GRADUALLY END FM NORTH TO SOUTH OVERNIGHT. TEMPS MAY BE COLD
ENOUGH FOR SOME SNOW OVER THE HIGHER MTNS ABV 11000 FT BEFORE PCPN
ENDS.
LONG TERM...MODELS SHOW THE WEAK UPPER TROUGH TO MOVE ACROSS THE
FORECAST AREA ON MONDAY...THEN UPPER RIDGING IS PROGGED INTO
TUESDAY AFTERNOON. SOUTHWESTERLY FLOW ALOFT MOVES IN TUESDAY
NIGHT...WITH AN UPPER TROUGH GETTING INTO THE NORTHERN GREAT BASIN
BY 12Z WEDNESDAY. THE QG VERTICAL VELOCITY FIELDS SHOW BENIGN
SYNOPTIC SCALE ENERGY OVER THE CWA MONDAY THROUGH TUESDAY NIGHT.
THE BOUNDARY LAYER PRESSURE AND WIND FIELDS SHOW SOUTHEASTERLIES
OVER THE PLAINS ON MONDAY...THEN NORMAL DIURNAL PATTERNS KICK IN
MONDAY NIGHT INTO TUESDAY. LOW LEVEL TROUGHING AND DOWNSLOPING ARE
BOTH PROGGED LATER TUESDAY INTO TUESDAY NIGHT. CONCERNING MOISTURE
..MONDAY DRIES OUT SOMEWHAT...WITH FURTHER DRYING ON TUESDAY.
PRECIPITABLE WATER VALUES ARE IN THE 0.75-0.85 INCH RANGE OVER THE
WESTERN PLAINS MONDAY...DRYING INTO THE 0.50 TO 0.75 INCH RANGE
BY LATER TUESDAY. VALUES ARE HIGHER OVER THE EASTERN PLAINS ON
MONDAY...BUT DRY TO SIMILAR VALUES BY LATER TUESDAY. THE BOUNDARY
LAYER DEW POINTS ARE PROGGED IN THE LOWER TO MID 50S F OVER THE
PLAINS MONDAY INTO TUESDAY MONRING...THEN THEY DECREASE INTO THE
40S TO LOWER 50S F LATER TUESDAY AND TUESDAY NIGHT. VALUES ARE IN
THE MID 30S TO MID 40S OVER THE MOUNTAINS ALL FOUR PERIODS. THERE
IS SOME CAPE AROUND BOTH LATE DAY MONDAY AND LATE DAY TUESDAY...
BUT NOTHING SIGNIFICANT. THE QPF FIELDS HAVE LIMITED MEASURABLE
RAINFALL AMOUNTS MONDAY...NOTHING MONDAY NIGHT OR TUESDAY MONRING
..THEN A TAD LATE DAY TUESDAY IN THE MOUNTAINS. SO FOR POPS...
20-40%S IN THE MOUNTAINS LATE DAY MONDAY AND LATE DAY TUESDAY. FOR
THE PLAINS...10-20%S LATE DAY MONDAY...NONE TUESDAY. FOR
TEMPERATURES...MONDAY`S HIGHS ARE 3-7 C WARMER THAN TODAY`S.
TUESDAY`S HIGHS ARE 1-4 C WARMER THAN MONDAY`S. FOR THE LATER DAYS
..WEDNESDAY THROUGH SATURDAY...MODELS BRING AN UPPER TROUGH ACROSS
THE CWA WEDNESDAY AFTERNOON INTO EARLY THURSDAY...ALONG WITH AN
ACCOMPANYING COLD FRONT. AFTER THAT...UPPER RIDGING MOVES IN
THROUGH SATURDAY. MOISTURE IS LIMITED AND TEMPERATURES ARE ABOVE
SEASONAL NORMALS.
AVIATION...CEILINGS SHOULD GRADUALLY DROP INTO THE IFR CATEGORY LATER
THIS MORNING WITH AREAS OF RAIN DEVELOPING. THIS ACTIVITY WILL
CONTINUE THRU THE AFTN BEFORE ENDING DURING THE EVENING HOURS.
OVERNIGHT LOW CEILINGS AND SOME FOG WILL BE POSSIBLE THRU MON
MORNING.
HYDROLOGY...WILL CONTINUE WITH THE FLASH FLOOD WATCH THROUGH 6 PM
THIS EVENING. AREAS OF RAIN WILL INCREASE THROUGH THE MORNING
HOURS AND CONTINUE THROUGH THE AFTERNOON IN THE MOUNTAINS AND
FOOTHILLS AND ALONG THE FRONT RANGE URBAN CORRIDER. RAINFALL
AMOUNTS OVER THE HIGHER TERRAIN THROUGH 6 PM MAY RANGE FROM 1 TO 2
INCHES WITH ONE HALF INCH TO ONE INCH AT LOWER ELEVATIONS. COULD
SEE A FEW LOCALIZED AREAS OF FLASH FLOODING HOWEVER BIGGEST
CONCERN WILL BE AN INCREASE IN ROCK AND MUD SLIDES IN THE
FOOTHILLS AND MOUNTAINS DUE TO EXTREMELY SATURATED GROUND.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
.RIVER FLOOD WARNINGS CONTINUE ALONG THE CACHE LA POUDRE...BIG
THOMPSON...AND SOUTH PLATTE RIVER OUT THROUGH JULESBURG.
.AREAL FLOOD WARNINGS UNTIL 9 PM THIS EVENING FOR COZ035..036..
038>041..043>045..048>50.
.FLASH FLOOD WATCH UNTIL 6 PM MDT THIS EVENING FOR COZ033>036-
038>041-043.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....RJK
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
925 AM MDT SUN SEP 15 2013
.UPDATE...
&&
.SHORT TERM...RAIN SHOWERS HAVE BEEN RAPIDLY DEVELOPING OVER THE
FOOTHILLS AND PLAINS DURING THE PAST SEVERAL HOURS. PLATTEVILLE
PROFILER SHOWING WEAK UPSLOPE FLOW FROM THE NORTHEAST HAS BEEN
DEEPENING OVER THE PAST SEVERAL HOURS TO MOUNTAIN TOP LEVEL. THE
WEAK FRONTAL BOUNDARY IS FINALLY BEGINNING TO PUSH SOUTH AND
SOUTHWEST AND JUST MOVING INTO THE FRONT RANGE AREA. FORECASTS
LOOK IN GOOD SHAPE FOR NOW.
.AVIATION...CEILINGS LOWERING AND WILL CONTINUE TO LOWER FROM THE
NORTH TO IFR CONDITIONS IN THE NEXT FEW HOURS AS RAIN BEGINS TO
SPREAD ACROSS THE AREA FROM THE NORTH AND NORTHEAST. RAINFALL
SHOULD BE DIMINISHING THIS EVENING WITH IMPROVING CONDITIONS.
POSSIBLE FOG LATER TONIGHT.
&&
.HYDROLOGY...RAIN DEVELOPING AND WILL BECOME MORE WIDESPREAD BY
LATER THIS MORNING OVER THE ENTIRE AREA...WITH HIGHER COVERAGE
OVER THE FOOTHILLS AND ADJACENT PLAINS. CURRENT RAINFALL OVER
LARIMER COUNTY GAUGES SHOWING RAINFALL RATES GENERALLY FROM .20 TO
.50 OF AN INCH PER HOUR WITH THE HEAVIER SHOWERS. JUST ISSUED AN
AREAL FLOOD WARNING FOR MUCH OF THE FRONT RANGE FOOTHILLS...AND
ADJACENT PLAINS AND STRETCHING NORTHEAST TO COVER AREAS ALONG THE
SOUTH PLATTE UP THROUGH JULESBURG AND AREAS ALONG THE CACHE LA
POUDRE. STILL COULD SEE 1 TO 2 INCHES OF ADDITIONAL RAINFALL
THROUGH THIS EVENING ESPECIALLY IN THE FOOTHILLS.
&&
.PREV DISCUSSION... /ISSUED 338 AM MDT SUN SEP 15 2013/
SHORT TERM...REMNANTS OF WK UPPER LEVEL TROUGH WILL SHEAR ACROSS THE
AREA THRU TONIGHT WITH SOME MINOR MID LVL ASCENT. MEANWHILE LOW
LVL WINDS ARE CURRENTLY NLY ALONG THE FNT RANGE BUT ARE FCST TO
BECOME MORE NELY LATER THIS MORNING INTO THE AFTN HOURS BEHIND A
COOL FNT. THIS SHOULD ALLOW FOR INCREASING PCPN IN THE NRN
FOOTHILLS AND MTNS EAST OF THE DIVIDE THIS MORNING WHICH WILL
SPREAD SOUTHWARD THRU THE DAY. AT THIS TIME HIGHEST PCPN AMOUNTS
SHOULD FOCUS IN AND NR THE FOOTHILLS AND IN THE MTNS EAST OF THE
DIVIDE. THE GFS AND HRRR SHOW POTENTIAL RAINFALL AMOUNTS RANGING
FROM 1 TO 2 INCHES OVER THE HIGHER TERRAIN WHILE THE ECMWF KEEPS
THE HEAVIER AMOUNTS FOCUSED EAST OF THE HIGHER TERRAIN OVER THE
FRONT RANGE URBAN CORRIDOR THRU THIS AFTN. AT THIS POINT WILL KEEP
THE HEAVIER AMOUNTS OVER THE HIGHER TERRAIN.
MEANWHILE WITH CONSIDERABLE CLOUD COVER THERE WILL BE LIMITED
INSTABILITY SO THE PCPN WILL BE MORE OF A STRATIFORM EVENT WITH
RAINFALL RATES MAINLY AROUND ONE QUARTER INCH PER HOUR. WILL KEEP
FFA IN PLACE HOWEVER BIGGWST CONCERNS WOULD BE CONSIDERABLE AMOUNT
OF ROCK AND MUD SLIDE ACTIVITY DUE TO EXTREMELY SATURATED GROUND.
HIGH THIS AFTERNOON OVER NERN CO MAY NOT GET MUCH ABV 60 EXCEPT OVER
THE FAR NERN CORNER WHERE HIGHS MAY GET CLOSE TO 70.
FOR TONIGHT THERE WILL BE SOME LINGERING RAIN THEU EVENING WHICH
WILL GRADUALLY END FM NORTH TO SOUTH OVERNIGHT. TEMPS MAY BE COLD
ENOUGH FOR SOME SNOW OVER THE HIGHER MTNS ABV 11000 FT BEFORE PCPN
ENDS.
LONG TERM...MODELS SHOW THE WEAK UPPER TROUGH TO MOVE ACROSS THE
FORECAST AREA ON MONDAY...THEN UPPER RIDGING IS PROGGED INTO
TUESDAY AFTERNOON. SOUTHWESTERLY FLOW ALOFT MOVES IN TUESDAY
NIGHT...WITH AN UPPER TROUGH GETTING INTO THE NORTHERN GREAT BASIN
BY 12Z WEDNESDAY. THE QG VERTICAL VELOCITY FIELDS SHOW BENIGN
SYNOPTIC SCALE ENERGY OVER THE CWA MONDAY THROUGH TUESDAY NIGHT.
THE BOUNDARY LAYER PRESSURE AND WIND FIELDS SHOW SOUTHEASTERLIES
OVER THE PLAINS ON MONDAY...THEN NORMAL DIURNAL PATTERNS KICK IN
MONDAY NIGHT INTO TUESDAY. LOW LEVEL TROUGHING AND DOWNSLOPING ARE
BOTH PROGGED LATER TUESDAY INTO TUESDAY NIGHT. CONCERNING MOISTURE
..MONDAY DRIES OUT SOMEWHAT...WITH FURTHER DRYING ON TUESDAY.
PRECIPITABLE WATER VALUES ARE IN THE 0.75-0.85 INCH RANGE OVER THE
WESTERN PLAINS MONDAY...DRYING INTO THE 0.50 TO 0.75 INCH RANGE
BY LATER TUESDAY. VALUES ARE HIGHER OVER THE EASTERN PLAINS ON
MONDAY...BUT DRY TO SIMILAR VALUES BY LATER TUESDAY. THE BOUNDARY
LAYER DEW POINTS ARE PROGGED IN THE LOWER TO MID 50S F OVER THE
PLAINS MONDAY INTO TUESDAY MONRING...THEN THEY DECREASE INTO THE
40S TO LOWER 50S F LATER TUESDAY AND TUESDAY NIGHT. VALUES ARE IN
THE MID 30S TO MID 40S OVER THE MOUNTAINS ALL FOUR PERIODS. THERE
IS SOME CAPE AROUND BOTH LATE DAY MONDAY AND LATE DAY TUESDAY...
BUT NOTHING SIGNIFICANT. THE QPF FIELDS HAVE LIMITED MEASURABLE
RAINFALL AMOUNTS MONDAY...NOTHING MONDAY NIGHT OR TUESDAY MONRING
..THEN A TAD LATE DAY TUESDAY IN THE MOUNTAINS. SO FOR POPS...
20-40%S IN THE MOUNTAINS LATE DAY MONDAY AND LATE DAY TUESDAY. FOR
THE PLAINS...10-20%S LATE DAY MONDAY...NONE TUESDAY. FOR
TEMPERATURES...MONDAY`S HIGHS ARE 3-7 C WARMER THAN TODAY`S.
TUESDAY`S HIGHS ARE 1-4 C WARMER THAN MONDAY`S. FOR THE LATER DAYS
..WEDNESDAY THROUGH SATURDAY...MODELS BRING AN UPPER TROUGH ACROSS
THE CWA WEDNESDAY AFTERNOON INTO EARLY THURSDAY...ALONG WITH AN
ACCOMPANYING COLD FRONT. AFTER THAT...UPPER RIDGING MOVES IN
THROUGH SATURDAY. MOISTURE IS LIMITED AND TEMPERATURES ARE ABOVE
SEASONAL NORMALS.
AVIATION...CEILINGS SHOULD GRADUALLY DROP INTO THE IFR CATEGORY LATER
THIS MORNING WITH AREAS OF RAIN DEVELOPING. THIS ACTIVITY WILL
CONTINUE THRU THE AFTN BEFORE ENDING DURING THE EVENING HOURS.
OVERNIGHT LOW CEILINGS AND SOME FOG WILL BE POSSIBLE THRU MON
MORNING.
HYDROLOGY...WILL CONTINUE WITH THE FLASH FLOOD WATCH THROUGH 6 PM
THIS EVENING. AREAS OF RAIN WILL INCREASE THROUGH THE MORNING
HOURS AND CONTINUE THROUGH THE AFTERNOON IN THE MOUNTAINS AND
FOOTHILLS AND ALONG THE FRONT RANGE URBAN CORRIDER. RAINFALL
AMOUNTS OVER THE HIGHER TERRAIN THROUGH 6 PM MAY RANGE FROM 1 TO 2
INCHES WITH ONE HALF INCH TO ONE INCH AT LOWER ELEVATIONS. COULD
SEE A FEW LOCALIZED AREAS OF FLASH FLOODING HOWEVER BIGGEST
CONCERN WILL BE AN INCREASE IN ROCK AND MUD SLIDES IN THE
FOOTHILLS AND MOUNTAINS DUE TO EXTREMELY SATURATED GROUND.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
.RIVER FLOOD WARNINGS CONTINUE ALONG THE CACHE LA POUDRE...BIG
THOMPSON...AND SOUTH PLATTE RIVER OUT THROUGH JULESBURG.
.AREAL FLOOD WARNINGS UNTIL 9 PM THIS EVENING FOR COZ035..036..
038>041..043>045..048>50.
.FLASH FLOOD WATCH UNTIL 6 PM MDT THIS EVENING FOR COZ033>036-
038>041-043.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....RJK
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
338 AM MDT SUN SEP 15 2013
.SHORT TERM...REMNANTS OF WK UPPER LEVEL TROUGH WILL SHEAR ACROSS THE
AREA THRU TONIGHT WITH SOME MINOR MID LVL ASCENT. MEANWHILE LOW
LVL WINDS ARE CURRENTLY NLY ALONG THE FNT RANGE BUT ARE FCST TO
BECOME MORE NELY LATER THIS MORNING INTO THE AFTN HOURS BEHIND A
COOL FNT. THIS SHOULD ALLOW FOR INCREASING PCPN IN THE NRN
FOOTHILLS AND MTNS EAST OF THE DIVIDE THIS MORNING WHICH WILL
SPREAD SOUTHWARD THRU THE DAY. AT THIS TIME HIGHEST PCPN AMOUNTS
SHOULD FOCUS IN AND NR THE FOOTHILLS AND IN THE MTNS EAST OF THE
DIVIDE. THE GFS AND HRRR SHOW POTENTIAL RAINFALL AMOUNTS RANGING
FROM 1 TO 2 INCHES OVER THE HIGHER TERRAIN WHILE THE ECMWF KEEPS
THE HEAVIER AMOUNTS FOCUSED EAST OF THE HIGHER TERRAIN OVER THE
FRONT RANGE URBAN CORRIDOR THRU THIS AFTN. AT THIS POINT WILL KEEP
THE HEAVIER AMOUNTS OVER THE HIGHER TERRAIN.
MEANWHILE WITH CONSIDERABLE CLOUD COVER THERE WILL BE LIMITED
INSTABILITY SO THE PCPN WILL BE MORE OF A STRATIFORM EVENT WITH
RAINFALL RATES MAINLY AROUND ONE QUARTER INCH PER HOUR. WILL KEEP
FFA IN PLACE HOWEVER BIGGWST CONCERNS WOULD BE CONSIDERABLE AMOUNT
OF ROCK AND MUD SLIDE ACTIVITY DUE TO EXTREMELY SATURATED GROUND.
HIGH THIS AFTERNOON OVER NERN CO MAY NOT GET MUCH ABV 60 EXCEPT OVER
THE FAR NERN CORNER WHERE HIGHS MAY GET CLOSE TO 70.
FOR TONIGHT THERE WILL BE SOME LINGERING RAIN THEU EVENING WHICH
WILL GRADUALLY END FM NORTH TO SOUTH OVERNIGHT. TEMPS MAY BE COLD
ENOUGH FOR SOME SNOW OVER THE HIGHER MTNS ABV 11000 FT BEFORE PCPN
ENDS.
.LONG TERM...MODELS SHOW THE WEAK UPPER TROUGH TO MOVE ACROSS THE
FORECAST AREA ON MONDAY...THEN UPPER RIDGING IS PROGGED INTO
TUESDAY AFTERNOON. SOUTHWESTERLY FLOW ALOFT MOVES IN TUESDAY
NIGHT...WITH AN UPPER TROUGH GETTING INTO THE NORTHERN GREAT BASIN
BY 12Z WEDNESDAY. THE QG VERTICAL VELOCITY FIELDS SHOW BENIGN
SYNOPTIC SCALE ENERGY OVER THE CWA MONDAY THROUGH TUESDAY NIGHT.
THE BOUNDARY LAYER PRESSURE AND WIND FIELDS SHOW SOUTHEASTERLIES
OVER THE PLAINS ON MONDAY...THEN NORMAL DIURNAL PATTERNS KICK IN
MONDAY NIGHT INTO TUESDAY. LOW LEVEL TROUGHING AND DOWNSLOPING ARE
BOTH PROGGED LATER TUESDAY INTO TUESDAY NIGHT. CONCERNING MOISTURE
...MONDAY DRIES OUT SOMEWHAT...WITH FURTHER DRYING ON TUESDAY.
PRECIPITABLE WATER VALUES ARE IN THE 0.75-0.85 INCH RANGE OVER THE
WESTERN PLAINS MONDAY...DRYING INTO THE 0.50 TO 0.75 INCH RANGE
BY LATER TUESDAY. VALUES ARE HIGHER OVER THE EASTERN PLAINS ON
MONDAY...BUT DRY TO SIMILAR VALUES BY LATER TUESDAY. THE BOUNDARY
LAYER DEW POINTS ARE PROGGED IN THE LOWER TO MID 50S F OVER THE
PLAINS MONDAY INTO TUESDAY MONRING...THEN THEY DECREASE INTO THE
40S TO LOWER 50S F LATER TUESDAY AND TUESDAY NIGHT. VALUES ARE IN
THE MID 30S TO MID 40S OVER THE MOUNTAINS ALL FOUR PERIODS. THERE
IS SOME CAPE AROUND BOTH LATE DAY MONDAY AND LATE DAY TUESDAY...
BUT NOTHING SIGNIFICANT. THE QPF FIELDS HAVE LIMITED MEASURABLE
RAINFALL AMOUNTS MONDAY...NOTHING MONDAY NIGHT OR TUESDAY MONRING
...THEN A TAD LATE DAY TUESDAY IN THE MOUNTAINS. SO FOR POPS...
20-40%S IN THE MOUNTAINS LATE DAY MONDAY AND LATE DAY TUESDAY. FOR
THE PLAINS...10-20%S LATE DAY MONDAY...NONE TUESDAY. FOR
TEMPERATURES...MONDAY`S HIGHS ARE 3-7 C WARMER THAN TODAY`S.
TUESDAY`S HIGHS ARE 1-4 C WARMER THAN MONDAY`S. FOR THE LATER DAYS
...WEDNESDAY THROUGH SATURDAY...MODELS BRING AN UPPER TROUGH ACROSS
THE CWA WEDNESDAY AFTERNOON INTO EARLY THURSDAY...ALONG WITH AN
ACCOMPANYING COLD FRONT. AFTER THAT...UPPER RIDGING MOVES IN
THROUGH SATURDAY. MOISTURE IS LIMITED AND TEMPERATURES ARE ABOVE
SEASONAL NORMALS.
&&
.AVIATION...CEILINGS SHOULD GRADUALLY DROP INTO THE IFR CATEGORY LATER
THIS MORNING WITH AREAS OF RAIN DEVELOPING. THIS ACTIVITY WILL
CONTINUE THRU THE AFTN BEFORE ENDING DURING THE EVENING HOURS.
OVERNIGHT LOW CEILINGS AND SOME FOG WILL BE POSSIBLE THRU MON
MORNING.
&&
.HYDROLOGY...WILL CONTINUE WITH THE FLASH FLOOD WATCH THROUGH 6 PM
THIS EVENING. AREAS OF RAIN WILL INCREASE THROUGH THE MORNING
HOURS AND CONTINUE THROUGH THE AFTERNOON IN THE MOUNTAINS AND
FOOTHILLS AND ALONG THE FRONT RANGE URBAN CORRIDER. RAINFALL
AMOUNTS OVER THE HIGHER TERRAIN THROUGH 6 PM MAY RANGE FROM 1 TO 2
INCHES WITH ONE HALF INCH TO ONE INCH AT LOWER ELEVATIONS. COULD
SEE A FEW LOCALIZED AREAS OF FLASH FLOODING HOWEVER BIGGEST
CONCERN WILL BE AN INCREASE IN ROCK AND MUD SLIDES IN THE
FOOTHILLS AND MOUNTAINS DUE TO EXTREMELY SATURATED GROUND.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR COZ033>036-038>041-
043.
&&
$$
SHORT TERM...RPK
LONG TERM....RJK
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1108 AM EDT Sun Sep 15 2013
.NEAR TERM [Through Tonight]...
The previous forecast remains on track with generally isolated to
scattered convection expected this afternoon and into early this
evening with easterly low level flow and a very weak front in the
area. The 700-500 mb lapse rates on the morning sounding were
somewhat steep around 6.2 C/km, and there is some mid-level dry air
present, so it would not be shocking to see a stronger storm or two
this afternoon, but nothing widespread is expected. Our 11z local
hi-res ARW run did have some decent updraft velocities with some
of the convection this afternoon. Only minor changes were made to
the PoP grid for today to account for the latest 11z local ARW and
the 12z HRRR trends, and scattered convection was also extended
through 03z tonight based on the hi-res guidance with a rapid
decrease after that.
&&
.SHORT TERM [Monday Through Monday Night]...
Through the early part of the week, the tri-state area will be
under the influence of a narrow east-west oriented ridge aloft. At
the surface, high pressure will persist along the eastern
seaboard, with Ingrid approaching the Mexican coast by Monday.
This combination will keep a decent easterly fetch in place across
the region. The east to southeast low-level flow should gradually
moisten the atmosphere and allow for slightly better coverage of
afternoon and evening convection, especially over the eastern
third of the forecast area. However, given the upper ridge in
place, forecast PoPs will remain at or below 30 percent through
Tuesday. The warm temperatures will continue with highs in the
lower 90s expected each day.
&&
.LONG TERM [Tuesday through Saturday]...
An upper level ridge is expected to dominate during the first half
of the period with surface ridging northeast of the area. This
should provide easterly surface flow with fairly low PoPs in the
20-30% range through most of the week. By late in the period, the
ridging may start to break down with a slight increase in moisture
leading to 30-40% PoPs. Near seasonal temperatures are expected.
&&
.AVIATION...
[Through 12z Monday] Low clouds have cleared out of all of the TAF
sites this morning with the exception of KABY, and they should
clear out of there between 15-16z. Otherwise, VFR conditions will
prevail through the remainder of the day with isolated to
scattered convection expected this afternoon.
&&
.MARINE...
East to southeast winds will slowly increase over the coastal
waters through mid-week as the region remains situated between
high pressure over the Mid-Atlantic states and Hurricane Ingrid
near the Mexican coast. Winds may approach exercise caution levels
by late Tuesday or Wednesday. Seas will increase by tonight as
long period swells from Ingrid reach the western marine zones.
Seas will likely rise to around 4 ft Monday afternoon with some 5
foot seas possible by mid-week.
&&
.FIRE WEATHER...
Relative humidity levels will remain above critical thresholds,
with dispersions remaining within acceptable levels. No fire
weather hazards anticipated.
&&
.HYDROLOGY...
Downward water level trends will continue for the next several
days as neither significant nor widespread rainfall is
anticipated.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 92 71 92 71 92 / 40 20 30 20 30
Panama City 90 75 90 75 91 / 30 30 20 20 20
Dothan 91 70 91 71 91 / 30 30 20 10 20
Albany 90 71 92 69 91 / 30 30 20 10 20
Valdosta 91 70 92 70 90 / 30 20 30 20 30
Cross City 92 69 91 70 90 / 40 20 30 20 30
Apalachicola 88 76 87 75 89 / 30 20 20 20 20
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
Near Term/Long Term/Aviation...DVD
Short Term/Marine/Hydrology...Camp
Fire Weather...Harrigan
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
117 AM EDT SUN SEP 15 2013
.AVIATION...
ISOLATED SHOWERS WILL CONTINUE TO DEVELOP OVER THE ATLANTIC WATERS
AND WORK INTO THE EAST COAST TAF SITES BEFORE DISSIPATING. SO HAVE
ADDED VCSH FOR ALL OF THE EAST COAST TAF SITES FOR THE EARLY
MORNING HOURS. THE SHOWERS WILL CONTINUE THROUGH THE MORNING HOURS
ON SUNDAY...BEFORE THUNDERSTORMS DEVELOP DURING THE AFTERNOON
HOURS ALONG THE SEA BREEZES. SO HAVE KEPT THE VCTS FOR THE EAST
COAST TAF SITES FOR THE SUNDAY AFTERNOON HOURS ALONG WITH VCTS FOR
KAPF TAF SITE FOR THE LATE MORNING INTO THE AFTERNOON HOURS.
THE WINDS WILL REMAIN EASTERLY AT ALL OF THE TAF SITES THROUGH
SUNDAY NIGHT...AS SPEEDS WILL BE 5 KNOTS OR LESS THROUGH 14Z
BEFORE INCREASING TO AROUND 10 KNOTS BY SUNDAY AFTERNOON. THE
CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITIONS THROUGH
SUNDAY AFTERNOON...AS THE TIMING OF THE SHOWERS AND THUNDERSTORMS
IS NOT KNOWN AT THIS TIME. SO WILL ADMIN THE TAFS WHEN THERE IS A
THREAT FOR SHOWERS OR THUNDERSTORMS FOR THE CEILING AND VIS.
&&
.AVIATION...54/BNB
.PREV DISCUSSION... /ISSUED 843 PM EDT SAT SEP 14 2013/
UPDATE...
CONDITIONS ARE QUIETING DOWN ACROSS SOUTH FLORIDA THIS EVENING.
CURRENT POPS ARE IN GOOD SHAPE. THERE ARE SOME SHOWERS AND A FEW
THUNDERSTORMS THAT WILL PROBABLY AFFECT THE ATLANTIC COASTAL
WATERS TONIGHT, BUT MOST SHOULD REMAIN WELL OFFSHORE. NO MAJOR
CHANGES MADE TO THE FORECAST WITH THIS UPDATE.
&&
PREV DISCUSSION... /ISSUED 720 PM EDT SAT SEP 14 2013/
AVIATION...
THE WEATHER WILL BE DRY OVER ALL OF THE TAF SITES TONIGHT...AS
THE WINDS WILL BE LESS THAN 5 KNOTS FROM THE EAST. THE WINDS WILL
THEN INCREASE TO AROUND 10 KNOTS ON SUNDAY FROM THE EAST AT ALL OF
SOUTH FLORIDA TAF SITES ALONG WITH SOME SHOWERS IN THE MORNING AND
THUNDERSTORMS IN THE AFTERNOON. SO WILL ADD VCSH TO ALL OF THE TAF
SITES AFTER 14Z AND VCTS AFTER 17Z...EXCEPT FOR KAPF TAF SITE
WHERE VCTS WILL BE PUT IN AFTER 15Z ON SUNDAY. THE CEILING AND VIS
WILL ALSO REMAIN IN THE VFR CONDITIONS TONIGHT INTO SUNDAY...AS
THE TIMING OF THE SHOWERS AND THUNDERSTORMS ON SUNDAY IS NOT KNOWN
AT THIS TIME.
&&
AVIATION...54/BNB
PREV DISCUSSION... /ISSUED 236 PM EDT SAT SEP 14 2013/
SYNOPSIS...
HIGH PRESSURE CENTERED NORTH OF THE REGION WILL ESTABLISH MODEST
BUT DEEP EASTERLY FLOW OVER SOUTH FLORIDA FOR MUCH OF NEXT WEEK.
THIS WILL ADVECT TROPICAL MOISTURE INTO THE AREA...RESULTING IN
INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS.
SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
SAL APPEARS TO BE SUCCESSFULLY SUPPRESSING CONVECTION TODAY OVER
MOST OF SOUTH FLORIDA. EASTERLY FLOW IS A BIT STRONGER TODAY THAN
YESTERDAY...SO GULF BREEZE HAS BEEN SLOW TO DEVELOP...WHILE
ATLANTIC BREEZE IS NOW INLAND OF METRO EAST COAST METRO AREAS.
ISOLATED TO SCATTERED CONVECTION IS STILL EXPECTED ALONG AND AHEAD
OF EITHER SEA-BREEZE...WITH GREATEST COVERAGE NEAR/WEST OF LAKE
OKEECHOBEE...WHERE LOW/MID-LEVELS ARE LEAST DRY AND DUST LAYER IS
LESS SIGNIFICANT. 18Z VSB SATELLITE ALREADY DEPICTS SIGNIFICANT CU
FIELD IN THIS REGION...AND HRRR FORECAST COMPOSITE REFLECTIVITY IS
MORE IMPRESSIVE THAN WAS INDICTED YESTERDAY AT THIS TIME. EXPECT
ACTIVITY TO HAVE SLOW SOUTHWARD DRIFT...THOUGH WITH LOW PWATS
FLOODING IS NOT A SIGNIFICANT THREAT. FORECAST AND 12Z SOUNDING
WERE NOT PARTICULARLY FAVORABLE FOR ANYTHING STRONGER THAN TYPICAL
SUMMERTIME CONVECTION...SO WILL LEAVE HWO MENTIONING FREQUENT
CLOUD-TO-GROUND LIGHTNING AS MAIN THREAT. CONVECTION WILL
DIURNALLY WANE.
UPPER-LEVEL TROUGH OVER EASTERN CONUS LIFTS NORTHWARD
TONIGHT...ALLOWING DEEP LAYER HIGH PRESSURE TO BUILD OVER THE
SOUTHEAST UNITED STATES AND ADJACENT ATLANTIC. WITH THE RIDGE AXIS
NORTH OF SOUTH FLORIDA...DEEP EASTERLY FLOW WILL
ESTABLISH...USHERING IN GREATER MOISTURE AND CAUSING AN UPWARD-
TREND IN POPS SUNDAY INTO MONDAY. SCATTERED TO PERHAPS NUMEROUS
CONVECTION IS EXPECTED BOTH AFTERNOONS. TEMPERATURES WILL BE
SOMEWHAT REGULATED BY THE INCREASE IN PCPN/CLOUDS...BUT OVERALL
WILL REMAIN NEAR NORMAL FOR MID-SEPTEMBER.
LONG TERM /TUESDAY THROUGH FRIDAY...
SIMILAR SYNOPTIC CONDITIONS WILL PERSIST THROUGH MUCH OF THE
PERIOD WITH MODELS PROJECTING LIKELY POPS. FOR NOW...CAPPING RAIN
CHANCES AT THIS TIME IN THE 40-50% RANGE. IN THE LATTER HALF OF
THE WEEK LOW LEVEL RIDGE PERSISTS AND WITH MOISTURE LEVELS
REMAINING CLOSE TO NORMAL RAIN CHANCES ARE FORECAST TO BE NEAR
CLIMO WITH DIURNALLY DRIVEN SHOWERS AND THUNDERSTORMS FORECAST
WEDNESDAY THROUGH FRIDAY. AS IN THE SHORT RANGE...TEMPERATURE
PATTERN OF NEARLY NORMAL DAYTIME HIGHS AND ABOVE NORMAL OVERNIGHT
LOWS WILL PERSIST.
MARINE...
EAST WINDS OF 5-15 KTS WILL PREVAIL FOR MOST OF THE NEXT 5 DAYS.
SEAS WILL BE 3 FEET OR LESS. SCATTERED THUNDERSTORMS SHOULD BE
PRESENT OVER THE WATERS BEGINNING SUNDAY AFTERNOON AND CONTINUE
THROUGH AT LEAST MID-WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 89 77 88 / 30 50 40 50
FORT LAUDERDALE 80 90 77 89 / 30 50 40 50
MIAMI 79 89 77 90 / 30 50 40 50
NAPLES 76 91 77 90 / 30 50 40 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...23/SK
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
957 AM EDT SUN SEP 15 2013
.SYNOPSIS...
ISSUED AT 527 AM EDT SUN SEP 15 2013
HIGH PRESSURE WILL GIVE WAY TO A FAST MOVING UPPER LEVEL
DISTURBANCE LATER TODAY. THIS SYSTEM WILL BRING SOME RAINFALL BY
MID AFTERNOON...ESPECIALLY ALONG AND WEST OF A KNOX TO COLDWATER
LINE. THE RAIN WILL THEN CONTINUE TO SPREAD EASTWARD INTO THE
EVENING HOURS. THE RAIN IS EXPECTED TO TAPER THROUGH THE
OVERNIGHT HOURS. IT WILL REMAIN COOLER THAN NORMAL TODAY...WITH
HIGHS IN THE MID 60S ACROSS SOUTHERN LOWER MICHIGAN TO THE LOWER
70S INTO NORTHWEST INDIANA. LOWS TONIGHT WILL DIP INTO THE UPPER
40S NORTH TO LOWER 50S SOUTH.
&&
.UPDATE...
ISSUED AT 919 AM EDT SUN SEP 15 2013
A FEW ADJUSTMENTS MADE TO CURRENT FORECAST TO SLOW DOWN ARRIVAL OF
MEASURABLE PRECIP INTO EARLY AFTERNOON AND BACK OFF A FEW DEGREES
ON AFTERNOON HIGHS ACROSS THE N/NW AREAS.
RADAR SHOWS RATHER IMPRESSIVE COVERAGE OF RAIN/RAINSHOWERS MOVING
INTO NW PARTS OF THE AREA AT PRESENT. HOWEVER...SFC OBS DEPICT A
DIFFERENT STORY WITH SOME SPRINKLES/LGT RAIN REACHING THE GROUND
WITH HIGH CLOUD BASES. 12Z SOUNDINGS FROM ILX...DTX AND DVN ALL
PAINTED THE PICTURE OF A LOT OF DRY AIR TO OVERCOME YET BELOW 700
MB (ROUGHLY 10000 FT). RAP SOUNDINGS AND LOOK AT PAST FEW RUNS OF
HRRR ALL SEEM TO POINT TOWARDS NOT A WHOLE LOT THIS MORNING BUT
IMPROVING CHANCES FOR MEASURABLE RAINFALL THIS AFTERNOON. QUICK
GLANCE AT OBS OUT OF BENTON HARBOR SHOW THAT LIGHT RAIN IS NOW
FALLING WITH A HUNDREDTH OF AN INCH RECORDED WITH NO CIG BELOW
12000 FT. HAVE ADJUSTED TRENDS SOMEWHAT TO KEEP SOME SLGT CHC/CHC
POPS IN FAR NW/N AREAS BUT SLOWED ARRIVAL OF STEADIER PRECIP UNTIL
MID TO LATE AFTERNOON. MAIN WINDOW OF RAINFALL (RATES MAYBE A
TENTH OF AN INCH OR MORE PER HOUR) WOULD APPEAR TO ARRIVE CLOSER
TO 22Z AND CONTINUE INTO EVENING (02 TO 03Z).
IN TERMS OF TEMPS...WITH NO INDICATIONS OF CLOUD COVER ACROSS THE
NORTH ERODING/MIXING IN ANY FASHION THROUGH THE DAY HAVE LOWERED
TEMPS A FEW DEGREES IN THE NORTH TO LOW-MID 60S AT BEST. WILL
LEAVE SOUTHERN AREAS NEAR 70 WITH FILTERED SUNSHINE LIKELY TO HELP
WITH SOME WARMING AS PCPN HOLDS OFF UNTIL LATER.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 527 AM EDT SUN SEP 15 2013
ROBUST/EFFICACIOUS SHORTWAVE ENERGY TO SHARPEN NORTHERN QUEBEC TO
SOUTHWESTERN GREAT LAKES TROF BY THIS EVENING. WALL OF COPIOUS
UPSTREAM MOISTURE WITH STEAM OF 8-11 G/KG 1000-850 MB RIVER
ALONG/WEST OF 95W...WITH MONSOONAL SOURCED MOISTURE FURTHER WEST
WITH SUPPLYING 200 PERCENT OF NORMAL PWAT THROUGHOUT CENTRAL
ROCKIES/GREAT BASIN. ANTECEDENT CONDS TO EAST HOWEVER QUITE
CONTRASTING WITH YDAY POST FRONTAL MIXOUT TO LOWER/MID 30S SFC
DEWPOINTS...STILL LANGUISHING IN THE LOWER 40S. FURTHERMORE DEARTH
OF MOISTURE THROUGH MIDLVS AT PRESENT WITH PLUME OF 30C PLUS 7-5H
LAYER DEWPOINT DIFFERENTIALS. THIS SHOULD HOLD UPSTREAM PRECIP AT
BAY FOR MOST OF THE DAY FAR ERN/SERN CWA. EJECTION OF LEAD SHORTWAVE
ACROSS IA TO SERN WI THIS AM...LARGELY SHUNTING RAFL TO W-NW OF
REGION WITH PRIMARY FOCUS ALONG NOSE OF 8H JETLET IMPINGING INTO
CENTRAL IA. NERN PERIPHERY OF THIS FEATURE SHIFTS INTO NORTHERN IL
BY LATE AM AND WEAKENS IN DEFERENCE TO SIGNIFICANTLY STRONGER ENERGY
WITHIN UPSTREAM. GIVEN DERISION OF SUBCLOUD CONDENSATION PRESSURE
DEFICITS WOULD ONLY ANTICIPATE SOME SPOTTY LIGHT RAFL POSSIBLE NWRN
CWA. THEREAFTER...INCREASE IN MIDLEVEL DEFORMATION ABOVE 925-8H
FRONTOGENESIS FROM FAR SWRN MI/NWRN IN/NRN IL INTO SCNTL IA...SHOULD
LEAD TO INCREASE IN SHRA CONVERGE. TOP/DOWN SATURATION TO GREATLY
SQUELCH DESTABILIZATION /MUCAPE AOB 250 J/KG WITH NEAR NIL CHANCES
FOR TSRA THIS AFTN. THEREAFTER...SHUNT OF WARM FRONT SWD INTO LOWER
OH VALLEY WITH MIDLVL TROF/60-70 KT JET AXIS PUSHING INTO LWR GREAT
LAKES BY AROUND 03 UTC...WITH ALL FOCUSES FOR SUBSTANTIVE LIFT
DIVERTING...WITH ONLY LIGHT SPOTTY RAFL AND SIG LOWERING OF POPS
REMAINDER OF TONIGHT. SLIGHT GRADIENT ADJUSTMENT TO TEMPS TODAY WITH
UPWARD NUDGE IN SWRN CWA WITH NERN FRINGE OF THERMAL RIDGE LAPPING
NEARBY...AND DOWNWARD HOLD ACRS NWRN/NRN CWA IN THICKER CLOUD
COVER/SLIGHT NEGATIVE 925MB THERMAL ADVECTION. AGAIN SLIGHT GRADIENT
ENHANCEMENT TONIGHT WITH STRONGER PULL OF COLD/DEEPER NERLY FLOW
ACROSS NORTHERN CWA. SOME UNCERTAINTY WITH RESPECT TO CLOUD
COVERAGE/CIGS LATE TONIGHT IN GUID...THOUGH HAVE TRENDED TOWARD
GREATER CLOUD COVER WITH ORPHANED LOW LEVEL MOISTURE PRESENT AMID
WELL MIXED/COOLING MIXED LAYER LIKELY TO MAINTAIN LOW STRATUS
THROUGH DAYBREAK MON.
&&
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 527 AM EDT SUN SEP 15 2013
CHILLY CANADIAN AIR WILL CONTINUE TO SPREAD OVER THE AREA MONDAY AS
HIGH PRESSURE DRIFTS ACROSS SOUTHEAST CANADA. GIVEN THE SUBSIDENCE
INVERSION AND MOISTURE TRAPPED BENEATH THE BASE OF THE INVERSION...
ANY EARLY DAY CLEARING SHOULD QUICKLY FILL BACK IN WITH CLOUDS...
MAKING FOR AN OVERALL CLOUDY TO MOSTLY CLOUDY AND COOL DAY. SO HAVE
LOWERED HIGHS A LITTLE MONDAY...MORE IN LINE WITH THE COOLER GFS/MAV.
CLOUDS SHOULD DISSIPATE MONDAY EVENING AND ALLOW OVERNIGHT LOWS TO
FALL WELL DOWN INTO THE 40S...ESPECIALLY OVER NORTHEAST AREAS.
AGAIN...FAVORED THE COOLER MAV. AS FOR THE MIDDLE OF THE WEEK...
FAVORED MORE OF A GFS ENSEMBLE BLEND/MEAN. THE ECMWF CONTINUES TO
HAVE MAJOR RUN TO RUN CONSISTENCY ISSUES RESOLVING THE MASS FIELDS
DOWNSTREAM OF THE WESTERN CONUS RIDGE. THE GFS ENSEMBLE MEAN APPEARS
TO BE THE BEST TO HANDLE THIS SCENARIO...HELPING TO DAMPEN OUT
OUTLIER SOLUTIONS AND FAVORING A MORE ACTIVE PATTERN WEDNESDAY NIGHT
THROUGH FRIDAY NIGHT. ACCORDINGLY...HAVE RAISED SHOWER/THUNDERSTORM
CHANCES THURSDAY NIGHT AND FRIDAY...AND HAVE INTRODUCED A CHANCE FOR
SHOWERS FRIDAY NIGHT GIVEN THE GFS TREND TOWARD A SLOWER SOLUTION.
IN FURTHER SUPPORT...THE GFS ENSEMBLE MEAN MOS HAS TRENDED HIGHER
RAIN CHANCES WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. AS FOR
THUNDERSTORMS/SEVERE STORM POTENTIAL...FAVORABLE MOISTURE SHOULD BE
AVAILABLE FOR STORMS...BUT WEAK BULK SHEAR AND LIMITED CAPE SHOULD
KEEP CHANCES FOR SEVERE STORMS RATHER REMOTE. KEPT FCST PERSISTENCE
WITH CHANCES FOR STORMS WEDNESDAY THROUGH FRIDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 702 AM EDT SUN SEP 15 2013
ONLY SLIGHT VARIANCE FROM 06 UTC TAFS. CONTINUE TO SUSPECT EROSION
ALONG LEADING EDGE OF RAFL FOR MUCH OF TODAY. OUTSIDE OF A FEW
SPRINKLES MIDDAY INTO KSBN EXPECT THE PRIMARY REFOCUS OF LIFT
TO HOLD UNTIL LATE AFTERNOON/EVENING THAT WILL PROVIDE THE BULK OF
LIGHT RAIN FOR NRN INDIANA TAF SITES. CONCERN CONTS FOR LOWERING
CIGS LATE IN FORECAST PD. GIVEN MOISTER SUB 825MB PROFILE AT KFWA
HAVE INTRODUCED TEMPO FUEL ALT CONDITIONS LATE IN FORECAST
PD...THOUGH REMAIN MORE OPTIMISTIC AT KSBN GIVEN GREATER
SUBSIDENCE/LOWER BLYR RH.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...FISHER
SYNOPSIS...MURPHY
SHORT TERM...MURPHY
LONG TERM...SKIPPER
AVIATION...MURPHY
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
632 PM CDT MON SEP 16 2013
.UPDATE...
ISSUED AT 630 PM CDT MON SEP 16 2013
CIRRUS SHIELD CONTINUES TO SPILL INTO THE SOUTHWEST HALF OF THE
CWA BUT THINS AS IT RUNS INTO THE DRY AIR FARTHER TO THE NORTHEAST...
WITH HIGH PRESSURE SITUATED ACROSS THE GREAT LAKES REGION. WILL
MONITOR THIS EVENING THE TEMPERATURE AND CLOUD TRENDS AND ADJUST
IF NEEDED.
&&
.SYNOPSIS...
ISSUED AT 317 PM CDT MON SEP 16 2013
LATEST SFC ANALYSIS WAS INDICATING HIGH PRESSURE DOMINATING THE
WESTERN GRT LKS AND UPPER MS RVR VALLEY. SUBSIDENCE FROM THE HEART
OF THIS FEATURE AND UPPER LEVEL RIDGING HELPING ERODE STRATOCU
FIELDS IN THE CWA...BUT SOME CLOUD FIELDS HOLDING FIRM ACRS SOUTH
CENTRAL INTO SOUTHEASTERN IA. ALOFT...WATER VAPOR IMAGERY WAS
INDICATING LINGERING MONSOONAL MOISTURE FIELDS ACRS THE CENTRAL
PLAINS OVER TO THE OH RVR/TN VALLEY REGIONS...WHILE MOISTURE OFF
INGRID SURGES INLAND ACRS MEX/SOUTHERN TX. UPSTREAM WAVE NOTED
ACRS THE NORTHWEST PLAINS ON WESTERN FLANK OF UPPER RIDGE AXIS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 317 PM CDT MON SEP 16 2013
TONIGHT...WILL FOLLOW LATEST RAP LLVL MOISTURE/RH GUIDANCE WHICH
SUGGESTS A CONTINUED CLEARING OF THE STRATOCU EXCEPT MAYBE THE FAR
SOUTHWESTERN CWA THROUGH THIS EVENING. IT ALSO SUGGESTS LLVL FLOW
TO VEER TO THE EAST-SOUTHEAST OVERNIGHT AND POSSIBLY START ADVECTING
MORE HIGHER RH LEVELS/STRATOCU FROM SOUTHEAST IL/IND LATE TONIGHT
AFTER MIDNIGHT. FOR NOW WILL MAINTAIN MOSTLY CLR SKIES OVERNIGHT
FOR BULK OF THE EASTERN HALF OF THE CWA AND BANK ON COOL LOWS IN THE
40S WITH LOW/DRY AMBIENT SFC DPTS. BUT SOME BUST POTENTIAL ON THE LOW
SIDE IF THE CLOUDS DO ADVECT IN FROM THE EAST LATER TONIGHT ALONG
WITH HIGHER DPTS FROM THOSE SAME AREAS. WILL KEEP LOWS IN THE LOW TO
MID 50S IN THE SOUTHWEST THIRD WITH EXPECTED MID DECK/HIGHER CLOUD
INCREASE LATER TONIGHT FROM THE SOUTHWEST IN THOSE AREAS. ELEVATED
WARM AIR ADVECTION PROCESSES ASSOCIATED WITH RIDGE-RIDING WAVE
MENTIONED ABOVE PUSHING ACRS EASTERN NEB AND WESTERN IA TO TAP IN THE
LINGERING MONSOONAL MOISTURE AND PRODUCE SHOWERS OVERNIGHT...BUT
RIDGING AND DRY AIR IN PLACE TO MAKE FOR MOST OF THE CWA REMAINING
DRY THROUGH 12Z TUE. MUCH OF INITIAL LIFT FROM APPROACHING UPPER WAVE
TO GO INTO TOP-DOWN SATURATION PROCESSES WITH VIRGA TO LIGHT
SHOWERS/SPRINKLES ACRS THE SOUTHWEST THIRD TOWARD DAYBREAK.
TUESDAY...DESPITE SOME DECENT MODEL INDICATED ELEVATED THTA-E
ADVECTION AND CONVERGENT REGIONS PUSHING ACRS THE SOUTHWESTERN
THIRD TO HALF OF THE DVN CWA AS THE DAY PROGRESSES...THE BATTLE
WILL BE ON WITH LARGE DRY AIRMASS TO THE EAST. LIKE THE PREVIOUS
SHIFT MENTIONED...SHARP MOISTURE AND PRECIP GRADIENTS MAY DEVELOP
LOCALLY WITH SOME AREAS/IN THE FAR SOUTHWEST/ GETTING UP TO A
QUARTER INCH OF RAIN BY MID AFTERNOON...AND AREAS EAST OF THE MS RVR
ESPECIALLY EAST CENTRAL AND NORTHEAST REMAINING DRY THROUGH 00Z WED.
WILL SPREAD IN POPS GENERALLY FROM WEST-SOUTHWEST TO EAST IN
DECREASING FASHION TUE. BUT SOME AREAS PROBABLY WARRANT CATEGORICAL
POPS WEST OF THE MS RVR. EXPECT MAINLY SHOWERS IN DECLINING FASHION
AS THEY SPREAD EASTWARD AND ENCOUNTER THE DRY AIR...BUT PROGGED
MID LEVEL MUCAPES OF 200-500 J/KG IF CORRECT...SUPPORTS ISOLATED
EMBEDDED THUNDER IN THE SOUTHWESTERN HALF ON TUE. TEMPS WILL BE A
CHALLENGE TUE DEPENDING ON CLOUD COVER AND EVAPO-COOLING FROM
PRECIP. WILL GO WITH COOLER VALUES HELD DOWN IN THE 60S IN THE
WEST WITH EARLIER ARRIVAL OF CLOUDS AND PRECIP...WARMER IN THE LOW
70S EAST OF THE MS RVR. ..12..
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 317 PM CDT MON SEP 16 2013
ACTIVE WX WILL BE SEEN ACROSS THE MIDWEST FOR THE REMAINDER OF THE
WORK WEEK WITH SEVERAL CHANCES FOR RAIN.
RAIN THAT MOVES INTO THE AREA TUESDAY AFTERNOON WILL OVERSPREAD THE
AREA TUESDAY NIGHT/WED. AS THE OVERALL FORCING WEAKENS ON WEDNESDAY
THE AREAL COVERAGE OF PRECIPITATION WILL DECREASE WEDNESDAY
AFTERNOON.
WED NIGHT/THURSDAY THE NEXT ROUND OF FORCING MOVES THROUGH THE AREA
HELPING TO RE-DEVELOP NEW CONVECTION. A RESPECTABLE LLJ DEVELOPS WED
NIGHT WHICH SHOULD RESULT IN CONSIDERABLE NOCTURNAL CONVECTION AFTER
MIDNIGHT AND INTO THURSDAY MORNING.
THE APPROACHING COLD FRONT ON THURSDAY IS EXPECTED TO HELP MAINTAIN
CONVECTION DURING THE AFTERNOON. THE AMOUNT OF CLOUD COVER MAY HOLD
DOWN TEMPERATURES SOMEWHAT BUT THEY SHOULD STILL BE CLOSE TO NORMAL.
THURSDAY NIGHT ON...
THE MODEL CONSENSUS HAS HIGH CHC/LIKELY POPS FOR THURS NIGHT AS THE
NEXT FRONT MOVES THROUGH THE AREA. THE FRONT WILL CLEAR THE AREA ON
FRIDAY SO ONLY SCHC/LOW CHC POPS ARE GIVEN BY THE MODEL CONSENSUS
FOR THE EASTERN HALF OF THE CWFA.
COOL CANADIAN HIGH BUILDS INTO THE GREAT LAKES FOR FRIDAY NIGHT
THROUGH SUNDAY NIGHT. THE MODEL CONSENSUS GIVES DRY CONDITIONS WITH
TEMPERATURES AVERAGING BELOW NORMAL.
SOUTHERLY FLOW DEVELOPING ON MONDAY WILL ALLOW TEMPERATURES TO AGAIN
WARM. THE MODEL CONSENSUS HAS DRY CONDITIONS FOR MONDAY WITH CHC
POPS FOR MONDAY NIGHT. ..08..
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 630 PM CDT MON SEP 16 2013
VFR CONDS THROUGH MOST OF THIS TAF CYCLE. WILL SPREAD LIGHT RAIN
AND SPRINKLES TO KCID/KMLI/KBRL TUESDAY AFTERNOON BUT VSBYS SHOULD
REMAIN P6SM. EAST WINDS 5 TO 10 KNOTS TONIGHT THEN SOUTHEAST
AROUND 10 KNOTS ON TUESDAY.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...HAASE
SYNOPSIS...12
SHORT TERM...12
LONG TERM...08
AVIATION...HAASE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
657 PM MDT MON SEP 16 2013
.UPDATE...
ISSUED AT 637 PM MDT MON SEP 16 2013
JUST COMPLETED AN EXTENSIVE UPDATE. MODELS PLAYING CATCHUP. SINCE
IT DID NOT CLEAR OFF...TEMPERATURES ARE STARTING OUT MUCH COOLER
THAN WHAT THE MODELS THINK. FOG HAS ALREADY DEVELOPED AND EXPECT
IT TO CONTINUE AS LOW LEVEL WIND FIELD WILL CONTINUE TO ADVECT IN
HIGHER DEWPOINTS. SO THROUGH TOMORROW MORNING HAVE INTRODUCED
WIDESPREAD FOG AND DRIZZLE. THE RUC IS CATCHING THIS THE BEST
RIGHT NOW WITH THE NAM/ECMWF NOT TOO FAR BEHIND.
CONSEQUENTLY ADJUSTED THE CLOUD COVER AND THE WIND FIELD...WHICH
THE RUC IS DOING THE BEST ON...AS WELL. ALSO CURRENT TEMPERATURES
WERE NEAR OR BELOW THE FORECAST MINS SO LOWERED THOSE ACCORDINGLY.
THE OTHER MAIN CHANGE WAS THE PRECIPITATION FORECAST. RIGHT NOW NOTHING
GOING ON...SO REMOVED THUNDERSTORMS THROUGH MID EVENING...AS ANOTHER
SHORTWAVE TROUGH MOVES IN FROM THE WEST. AT THE SAME TIME A RATHER
STRONG 700 MB WARM AIR ADVECTION DEVELOPS AS A WEAK RIGHT REAR
QUADRANT OF 250 MB JET AFFECTS THE AREA AS WELL.
THESE ALL COME TOGETHER AND INCREASE IN STRENGTH AS THE NIGHT GOES
ON. THETA-E LAPSE RATES ARE VERY FAVORABLE FOR RESPONSE TO THE
LIFT. ELEVATED CAPE INCREASES AS ELEVATED CINH DECREASES. RIGHT
NOW THE BEST CHANCE FOR THUNDERSTORMS WILL BE AFTER 06Z AND IN THE
EASTERN HALF. WOULD NOT BE SURPRISED IF THUNDERSTORMS BECOME RATHER
STRONG CONSIDERING THE AMOUNT OF CAPE AND THE VERY FAVORABLE LAPSE
RATES.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 1148 AM MDT MON SEP 16 2013
A COOL HIGH PRESSURE AREA REMAINS IN PLACE OVER THE FORECAST AREA
TODAY AS A FEW LIGHT TO MODERATE SHOWERS MOVE NORTHEASTWARD ACROSS
THE EASTERN SECTIONS OF THE FORECAST AREA. THESE SHOWERS ARE A
RESULT OF A COUPLE OF SHORT WAVE TROUGHS IN THE UPPER FLOW MOVING
EAST OF THE ROCKIES AND ACROSS THE CENTRAL HIGH PLAINS REGION THIS
AFTERNOON AND EVENING. EXPECT A FEW MORE SHOWERS TO DEVELOP AS A
SECOND WEAKER SHORT WAVE TROUGH FOLLOWS IN ITS PATH. BEHIND THOSE
WAVES A WEAK RIDGE AND MORE WESTERLY FLOW MOVES EAST OF THE
ROCKIES WITH AN AREA OF SUBSIDENCE ACROSS THE FORECAST AREA ON
TUESDAY AND A LEE TROUGH THAT DEEPENS ALONG THE FRONT RANGE OF
WYOMING AND COLORADO. AS THIS TROUGH DEEPENS...THE HIGH PRESSURE
AREA MOVES EAST AND THE MOIST RETURN FLOW BEGINS TO MOVE OUT OF
THE REGION TO BE REPLACED BY A DRYER SOUTH TO SOUTHWEST NEAR
SURFACE FLOW. LOW CLOUDS AND FOG THAT ARE EXPECTED TO DEVELOP
IN THE SATURATED AIR MASS ACROSS THE AREA OVERNIGHT ARE EXPECTED TO
DIMINISH BY LATE TUESDAY AFTERNOON AND EVENING WITH A RETURN OF
HIGH TEMPERATURES IN THE 80S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 219 PM MDT MON SEP 16 2013
A SHORTWAVE RIDGE WILL BE OVER THE PLAINS TUESDAY NIGHT FOLLOWED BY
WESTERLY FLOW THROUGH THURSDAY AS A TROUGH MOVES ACROSS THE NORTHERN
PLAINS. A SURFACE TROUGH WILL EXTEND SOUTH INTO EASTERN COLORADO
TUESDAY NIGHT/WEDNESDAY. THIS TROUGH WILL MOVE SOUTHEAST INTO
NORTHWEST KANSAS WEDNESDAY NIGHT. HIGH PRESSURE WILL MOVE INTO
NORTHWEST KANSAS THURSDAY.
CONDITIONS WILL REMAIN DRY TUESDAY NIGHT AND WEDNESDAY DUE TO
SUBSIDENCE OVER THE AREA. SOME DYNAMICS MOVE INTO THE AREA WEDNESDAY
NIGHT BUT MOISTURE IS NOT IMPRESSIVE SO WILL CONTINUE SLIGHT CHANCE
POPS FOR THUNDERSTORMS. DYNAMICS STILL REMAIN OVER THE FA EAST OF
THE COLORADO BORDER THURSDAY MORNING AND SHIFT EAST SOME THURSDAY
AFTERNOON BEFORE MOVING OUT OF THE AREA. ONCE AGAIN, H8-7 LAYER
MEAN RH IS LACKING SO WILL CONTINUE SLIGHT CHANCE POPS.
850MB TEMPERATURES SUPPORT MAX TEMPERATURES REACHING THE UPPER
80S/LOWER 90S WEDNESDAY. MAX TEMPERATURES SHOULD COOL TO THE 70S
THURSDAY BEHIND THE TROUGH. MIN TEMPERATURES TUESDAY NIGHT WILL BE
IN THE UPPER 50S/LOWER 60S COOLING TO THE MID 50S TO LOWER 60S
WEDNESDAY NIGHT.
IN THE EXTENDED...(THURSDAY NIGHT THROUGH MONDAY)...THIS PART OF THE
FORECAST WILL BE DRY THROUGH SATURDAY NIGHT WITH A RIDGE AND
SUBSIDENCE OVER THE REGION. THE RIDGE SHIFTS EAST SUNDAY ALLOWING A
TROUGH TO MOVE EAST INTO THE AREA. SLIGHT CHANCE TO CHANCE POPS ARE
SUPPORTED WITH NIL POPS FOR MONDAY
MAX TEMPERATURES WILL WARM UP INTO THE 80S UNDERNEATH THE INFLUENCE
OF THE RIDGE AND THEN COOL TO THE MID AND UPPER 70S MONDAY BEHIND
THE EXITING SHORTWAVE. MIN TEMPERATURES WILL RESIDE IN THE LOWER TO
MID 50S THURSDAY AND FRIDAY NIGHTS MODERATING TO THE MID/UPPER 50S
SATURDAY/SUNDAY NIGHTS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 637 PM MDT MON SEP 16 2013
IFR TO LIFR CONDITIONS EXPECTED TO BECOME EVEN VLIFR...ESPECIALLY
AT KGLD...FOR THE REST OF TONIGHT AND TOMORROW MORNING. AT THAT
TIME CONDITIONS WILL IMPROVE AND BE VFR BY EARLY AFTERNOON. EXPECT
THUNDERSTORMS TO DEVELOP...MAINLY AFTER 06Z AND MAINLY OVER THE
EASTERN HALF OF THE FORECAST AREA. THIS MEANS THAT KMCK WILL HAVE
THE BEST CHANCE OF BEING AFFECTED BY THUNDERSTORMS. HOWEVER...DID
NOT INCLUDE ANY MENTION RIGHT NOW. WILL CONTINUE MONITOR LATEST
DATA CLOSELY AND WILL UPDATE BY LATER THIS EVENING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...LOCKHART
LONG TERM...FS
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS WICHITA KS
301 PM CDT SUN SEP 15 2013
.SYNOPSIS...
ISSUED AT 250 PM CDT SUN SEP 15 2013
A COLD FRONT STRETCHING FROM NORTHEAST TO CENTRAL AND
SOUTHWEST KANSAS IS KEEPING ON ITS SOUTHEAST TRACK. THIS FRONT WILL
PUSH THROUGH THIS EVENING...AND A RIDGE WILL BE ON ITS TAILS FOR
MONDAY. A FAIRLY ACTIVE PATTERN IS IN PLACE TO KEEP SYSTEMS MOVING
ACROSS THE CONUS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 250 PM CDT SUN SEP 15 2013
AS MENTIONED IN THE SYNOPSIS...THE COLD FRONT SHOULD CONTINUE TO
SLIDE THROUGH THE REST OF KANSAS AND INTO OKLAHOMA THIS EVENING
AND TONIGHT. SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED TO
BUBBLE UP ALONG AND BEHIND THIS FRONTAL FEATURE THIS AFTERNOON
GIVEN DAYTIME HEATING AND . SOME OF THE STORMS COULD BE STRONG
WITH ABOVE 1K J/KG CAPE VALUES MAINLY IN SOUTH CENTRAL
KANSAS...HOWEVER 0-6KM BULK SHEAR VALUES ARE LESS THAN 30KTS
ACCORDING TO THE MODELS DURING THIS RESPECTIVE TIME FRAME FOR ALL
BUT THE RUC WHICH HAS VALUES JUST AT 40KTS. PRECIPITATION ACTIVITY
IS STILL ANTICIPATED TO LINGER INTO MUCH OF MONDAY AND TUESDAY
WHEN ANOTHER SHORTWAVE IN THE MID LEVELS MOVES THROUGH THE AREA.
ANOTHER TROUGH AT 500MB AND 700MB IS GOING TO MOVE ONSHORE ON
TUESDAY...WHILE THE 850MB TROUGH HALTS AND STARTS TO DEVELOP ALONG
THE FRONT RANGE. EVENING POPS ON TUESDAY WERE SLIGHTLY DROPPED
FROM THE PREVIOUS FORECAST...BUT THE MAIN TRENDS FOR ALL OTHER
PARAMETERS WERE MAINTAINED. COOLER AIR ON MONDAY AND CLOUD COVER
WILL KEEP HIGHS BELOW SEASONAL NORMAL BY 5 DEGREES IN SOUTH
CENTRAL KANSAS AND AS MUCH AS 10 DEGREES IN CENTRAL KANSAS.
TUESDAY SHOULD REBOUND BACK TO ABOVE NORMAL IN THE MID TO UPPER
80S.
JUANITA
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 250 PM CDT SUN SEP 15 2013
WEDNESDAY THRU THURSDAY: IN THIS TIME FRAME...THE NEXT SYSTEM IS
EXPECTED TO MOVE THROUGH THE PLAINS. WHILE THE CENTER OF THE LOW
STAYS ACROSS THE CANADIAN AND U.S. BORDER AND MOVES THE FRONT ON
WEDNESDAY INTO THURSDAY...THERE ARE MODEL DIFFERENCES IN ITS TIMING.
ECMWF IS MORE PROGRESSIVE WITH PUSHING THE FRONT THROUGH THE AREA.
THERE COULD BE A CHANGE IN PRECIP ACTIVITY WITH THIS DIFFERENCE.
POPS WERE SLIGHTLY INCREASED FOR THURSDAY AND THURSDAY EVENING WITH
A SMIDGEN OF BETTER CONSISTENCY.
FRIDAY THRU SUNDAY: CURRENT MODEL PREDICTIONS OF THIS TIME FRAME MAKE IT
APPEAR THAT A RIDGE WILL BE IN PLACE. MODEL DISCREPANCIES BEGIN AT
THE START OF NEXT WEEK WHICH MAY MAKE AN IMPACT TO THE FORECAST
FOR SUNDAY DEPENDING ON THE POTENTIAL PROGRESSIVE NATURE OF THE
SYSTEM. THIS IS TOO FAR OUT FOR ANY CERTAINTY IN EITHER PREDICTION
OF THE NEXT SYSTEM TO MOVE THROUGH THE CENTRAL UNITED STATES.
SLIGHT CHANCES WERE PUT IN FOR SUNDAY...BUT AGAIN CONFIDENCE IS
LOW AT THIS TIME.
JUANITA
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1245 PM CDT SUN SEP 15 2013
SCATTERED THUNDERSTORMS EXPECTED TO ERUPT BY 21-22Z NEAR HUT-
ICT...ALONG A COLD FRONT SURGING SOUTH...WITH THIS ACTIVITY
GETTING INTO KCNU 00-01Z. STRONGEST ACTIVITY WILL BE CAPABLE OF
STRONG/GUSTY ERRATIC WINDS...DIME-QUARTER SIZE HAIL AND LOCALLY
HEAVY RAIN. BEHIND INITIAL CONVECTION...OTHER AREAS OF
SHOWERS/THUNDERSTORMS MAY REDEVELOP NORTH OF THE FRONT LATER THIS
EVENING AS LOW-LEVEL JET STRENGTHENS...POSSIBLY AFFECTING THE
ENTIRE AREA. FURTHERMORE...LOW MVFR TO POTENTIALLY IFR CIGS
EXPECTED TO SPREAD SOUTH IN WAKE OF THE FRONT THIS AFTERNOON AND
TONIGHT...ALONG WITH MODEST NORTH/NORTHEAST WINDS.
ADK
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 65 78 65 86 / 60 50 30 30
HUTCHINSON 62 75 63 85 / 60 50 30 30
NEWTON 61 74 62 83 / 60 50 30 30
ELDORADO 63 78 63 84 / 60 50 30 30
WINFIELD-KWLD 67 81 65 86 / 50 60 30 30
RUSSELL 58 72 61 86 / 40 40 40 30
GREAT BEND 59 73 62 85 / 40 40 40 30
SALINA 60 73 62 84 / 40 40 40 40
MCPHERSON 61 74 63 84 / 50 40 30 40
COFFEYVILLE 66 83 65 86 / 60 60 40 40
CHANUTE 64 78 63 85 / 60 60 40 40
IOLA 63 76 62 84 / 60 50 40 40
PARSONS-KPPF 65 81 64 85 / 60 60 40 40
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1200 PM CDT Sun Sep 15 2013
...Update to aviation for 18 Zulu time TAFs...
.SYNOPSIS...
ISSUED AT 1010 AM CDT SUN SEP 15 2013
The 15.12Z raob map showed southwesterly wind vectors with magnitudes
in the 35-40 kt over Kansas. @ 500 hPa, an elongated trof was located
across the northeast Pacific. Shortwave ridging was noted across the
northern Rockies. Another broad ridge stretched across the Deep South.
@ 700 hPa and 850 hPa, some drying was noted at KDDC. The pwat was down
to 1.30", which, statistically speaking, is still fairly high for this
time of year. 850 hPa also showed more warming with observed at 21C.
At the sfc, a frontal boundary was analyzed across western Kansas. In
the tropics, Hurricane Ingrid was located at 22.5N 95.8W @ 15.15Z. Invest
94L 950 miles southwest of the Azores. Tropical Storm Manuel was
at 18.5N 103.9W @ 15.15Z.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 403 AM CDT SUN SEP 15 2013
An upper level trough over the Rockies will continue to eject
minor waves into the plains today and tonight. Meanwhile, a
shortwave trough progressing southeastward across the upper Midwest
will help push a fairly strong cold front into southwest Kansas
this afternoon. Thunderstorm chances are fairly good along
and ahead of the front; but these are not expected to be
severe given the lack of shear and marginal surface based CAPE.
The best chance of storms is along and southeast of a line from
Dodge City to Larned after 4 pm. Opted to go with a non-diurnal
temperature trend for today by using the 06Z RUC as a 1st guess,
then modifying the hourly temperatures that seemed too hot ahead
of the front. Temperatures should be falling in the afternoon from
Dodge City northward to interstate 70 as low level stratus invades
from the northern plains. Late afternoon temperatures may be in the
upper 60s around Wakeeney and in the lower 90s for areas southeast
of Dodge City around Medicine Lodge. For tonight, some elevated
showers and thunderstorm may persist through the nigh as upper
level troughing hangs back to the west over Colorado. However,
if the lower levels are stabilized too much by the deep cold
advection, then this activity may not pan out at all. Temperatures
should fall into the 50s to lower 60s by advection alone by
Tuesday morning with low stratus hanging tough.
.LONG TERM...(Monday through Saturday)
ISSUED AT 357 AM CDT SUN SEP 15 2013
There is considerable uncertainty in synoptic scale details in the
extended period with a blocky flow regime likely to persist in the
United States through the last week of September. Global scale
forcing is weak, and the numerical models exhibit considerable
spread, especially in the week two period. The Madden Julian
Oscillation is weak, but most of the global scale models do suggest
a low amplitude coherent signal in Phase 5 of the Wheeler-Hendon
Phase Space Diagram this week. However, the low amplitude of the
signal and the generally weak correlation with mid latitude weather
this time of the year provide little to increase confidence in the
extended forecast. Global relative angular momentum continues below
climatological values, and the recent spike in mountain torque has
ended. The net result is that there is little signal in the Global
Wind Oscillation to provide much guidance, either.
The upper level high over southeastern Alberta will break down and
progress east today and Monday as the upper low near 130W progresses
into the Pacific Northwest. The upper level trough in the northern
stream from near Lake Superior to South Dakota will continue to dig
into the long wave trough in the upper Midwest, and a cold front
will move across most of Kansas before becoming stationary tonight
near the Kansas/Oklahoma border this evening. Most of Kansas will be
under moist east flow Monday with considerable cloud cover, although
the cloudiness may break in the southwest corner of the state during
the afternoon. The cold trough over the Rockies will progress into
Kansas Monday as the block breaks down. Weak upward vertical motion
in a moist atmosphere will favor continued chances for showers and a
few thunderstorms Monday. Instability should be better in far
southwest Kansas near the old frontal zone, especially if breaks in
the cloudiness develop during the afternoon. A modest low level jet
with H8 winds around 30kts will develop Monday night as pressures
fall in the Northern Plains, and low level isentropic lifting will
favor shower and thunderstorm development during the nighttime
hours. The best isentropic lift will propagate into northern Kansas
after 06Z, and thunderstorm chances will decrease in southwest
Kansas.
The surface warm front will mix northward quickly after sunrise
Tuesday, and an elevated mixed layer will spread across western
Kansas during the day. Tuesday and Wednesday should be breezy and
warm with highs in the upper 80s and lower 90s in most areas. By
Wednesday, the jet streak near 170W will dig into the northern
Rockies and will progress slowly eastward Thursday and Friday. The
ECMWF and GEM are more progressive with the trough than the GFS and
develop a deeper closed cyclone than the GFS by 00Z Friday. Most of
the GEM ensemble members also are more progressive than the
deterministic GFS, as are many of the GFS ensemble members. The
preponderance of evidence supports a solution more similar to the
ECMWF later this week. A cold front will move into northwest Kansas
Wednesday evening and should progress across all of western Kansas
by late Thursday morning. Warm temperatures aloft and timing of the
frontal passage during the nighttime and early morning hours are not
favorable for much thunderstorm development along the boundary. Some
post-frontal development is possible Thursday as mid level
temperatures cool and western Kansas comes under the entrance region
of a jet streak.
Upper level ridging will build over Kansas Friday, and the next
upper level trough will dig into the northern Rockies Saturday. The
ECMWF closes off another cyclone over eastern Montana Sunday and
wallows a closed low into the central plains by Tuesday, while the
GFS and most if its ensemble members maintain a more open wave much
farther north than the ECMWF. Confidence is low with evolution of
the upper level trough. The ECMWF may be trending in the right
direction given the blocky flow in North America, but a few more
runs are needed before accepting the ECMWF solution.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1200 PM CDT SUN SEP 15 2013
Messy TAF with deteriorating flight conditions through PD. Stratus is
wrapping around behind a cold front. This front is bisecting the region
and should traverse across the terminals in the next 6 hours. MVFR to
IFR cigs expected in the wake of the front as post frontal lifting occurs.
Thunderstorms should remain southeast of the terminals (although KDDC
will be close). Post frontal showers late tonight possible as well.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 85 58 73 63 / 30 40 40 30
GCK 81 57 72 61 / 20 30 40 30
EHA 84 57 78 62 / 30 30 40 40
LBL 86 58 77 62 / 30 30 40 40
HYS 77 57 71 62 / 20 30 30 40
P28 91 62 79 66 / 40 60 50 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Sugden
SHORT TERM...Finch
LONG TERM...Ruthi
AVIATION...Sugden
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1010 AM CDT Sun Sep 15 2013
...Update to synopsis...
.SYNOPSIS...
ISSUED AT 1010 AM CDT SUN SEP 15 2013
The 15.12Z raob map showed southwesterly wind vectors with magnitudes
in the 35-40 kt over Kansas. @ 500 hPa, an elongated trof was located
across the northeast Pacific. Shortwave ridging was noted across the
northern Rockies. Another broad ridge stretched across the Deep South.
@ 700 hPa and 850 hPa, some drying was noted at KDDC. The pwat was down
to 1.30", which, statistically speaking, is still fairly high for this
time of year. 850 hPa also showed more warming with observed at 21C.
At the sfc, a frontal boundary was analyzed across western Kansas. In
the tropics, Hurricane Ingrid was located at 22.5N 95.8W @ 15.15Z. Invest
94L 950 miles southwest of the Azores. Tropical Storm Manuel was
at 18.5N 103.9W @ 15.15Z.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 403 AM CDT SUN SEP 15 2013
An upper level trough over the Rockies will continue to eject
minor waves into the plains today and tonight. Meanwhile, a
shortwave trough progressing southeastward across the upper Midwest
will help push a fairly strong cold front into southwest Kansas
this afternoon. Thunderstorm chances are fairly good along
and ahead of the front; but these are not expected to be
severe given the lack of shear and marginal surface based CAPE.
The best chance of storms is along and southeast of a line from
Dodge City to Larned after 4 pm. Opted to go with a non-diurnal
temperature trend for today by using the 06Z RUC as a 1st guess,
then modifying the hourly temperatures that seemed too hot ahead
of the front. Temperatures should be falling in the afternoon from
Dodge City northward to interstate 70 as low level stratus invades
from the northern plains. Late afternoon temperatures may be in the
upper 60s around Wakeeney and in the lower 90s for areas southeast
of Dodge City around Medicine Lodge. For tonight, some elevated
showers and thunderstorm may persist through the nigh as upper
level troughing hangs back to the west over Colorado. However,
if the lower levels are stabilized too much by the deep cold
advection, then this activity may not pan out at all. Temperatures
should fall into the 50s to lower 60s by advection alone by
Tuesday morning with low stratus hanging tough.
.LONG TERM...(Monday through Saturday)
ISSUED AT 357 AM CDT SUN SEP 15 2013
There is considerable uncertainty in synoptic scale details in the
extended period with a blocky flow regime likely to persist in the
United States through the last week of September. Global scale
forcing is weak, and the numerical models exhibit considerable
spread, especially in the week two period. The Madden Julian
Oscillation is weak, but most of the global scale models do suggest
a low amplitude coherent signal in Phase 5 of the Wheeler-Hendon
Phase Space Diagram this week. However, the low amplitude of the
signal and the generally weak correlation with mid latitude weather
this time of the year provide little to increase confidence in the
extended forecast. Global relative angular momentum continues below
climatological values, and the recent spike in mountain torque has
ended. The net result is that there is little signal in the Global
Wind Oscillation to provide much guidance, either.
The upper level high over southeastern Alberta will break down and
progress east today and Monday as the upper low near 130W progresses
into the Pacific Northwest. The upper level trough in the northern
stream from near Lake Superior to South Dakota will continue to dig
into the long wave trough in the upper Midwest, and a cold front
will move across most of Kansas before becoming stationary tonight
near the Kansas/Oklahoma border this evening. Most of Kansas will be
under moist east flow Monday with considerable cloud cover, although
the cloudiness may break in the southwest corner of the state during
the afternoon. The cold trough over the Rockies will progress into
Kansas Monday as the block breaks down. Weak upward vertical motion
in a moist atmosphere will favor continued chances for showers and a
few thunderstorms Monday. Instability should be better in far
southwest Kansas near the old frontal zone, especially if breaks in
the cloudiness develop during the afternoon. A modest low level jet
with H8 winds around 30kts will develop Monday night as pressures
fall in the Northern Plains, and low level isentropic lifting will
favor shower and thunderstorm development during the nighttime
hours. The best isentropic lift will propagate into northern Kansas
after 06Z, and thunderstorm chances will decrease in southwest
Kansas.
The surface warm front will mix northward quickly after sunrise
Tuesday, and an elevated mixed layer will spread across western
Kansas during the day. Tuesday and Wednesday should be breezy and
warm with highs in the upper 80s and lower 90s in most areas. By
Wednesday, the jet streak near 170W will dig into the northern
Rockies and will progress slowly eastward Thursday and Friday. The
ECMWF and GEM are more progressive with the trough than the GFS and
develop a deeper closed cyclone than the GFS by 00Z Friday. Most of
the GEM ensemble members also are more progressive than the
deterministic GFS, as are many of the GFS ensemble members. The
preponderance of evidence supports a solution more similar to the
ECMWF later this week. A cold front will move into northwest Kansas
Wednesday evening and should progress across all of western Kansas
by late Thursday morning. Warm temperatures aloft and timing of the
frontal passage during the nighttime and early morning hours are not
favorable for much thunderstorm development along the boundary. Some
post-frontal development is possible Thursday as mid level
temperatures cool and western Kansas comes under the entrance region
of a jet streak.
Upper level ridging will build over Kansas Friday, and the next
upper level trough will dig into the northern Rockies Saturday. The
ECMWF closes off another cyclone over eastern Montana Sunday and
wallows a closed low into the central plains by Tuesday, while the
GFS and most if its ensemble members maintain a more open wave much
farther north than the ECMWF. Confidence is low with evolution of
the upper level trough. The ECMWF may be trending in the right
direction given the blocky flow in North America, but a few more
runs are needed before accepting the ECMWF solution.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
ISSUED AT 700 AM CDT SUN SEP 15 2013
A cold front will move across western Kansas today and should extend
from southeast Kansas to the central Texas Panhandle by Monday
morning. Southwest winds 10 to 15 knots will become north to
northeast at 10 to 15 knots following passage of the cold front.
Local visibilities 4-5 miles in mist can be expected around sunrise
today. Scattered clouds AOA 100 will prevail this morning, and
scattered cumulus clouds with bases near 060 will develop by late
morning. Ceilings 015 to 025 will spread southward behind the cold
front, reaching HYS around 1700Z and GCK and DDC after 0000Z.
Scattered thunderstorms will form along the front around 21Z near
DDC and move east. Upslope flow in eastern Colorado will favor
development of showers and thunderstorms that will weaken and
propagate into western Kansas this evening, reaching GCK around
0500Z and DDC and HYS after 0700Z.
Moist east to northeast upslope flow and stratus with bases 010-020
will persist Monday. An upper level trough will move from the
Rockies to western Kansas Monday and will provide enough upward
vertical motion to support scattered showers and a few
thunderstorms.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 85 58 73 63 / 30 40 40 30
GCK 81 57 72 61 / 20 30 40 30
EHA 84 57 78 62 / 30 30 40 40
LBL 86 58 77 62 / 30 30 40 40
HYS 76 57 71 62 / 20 30 30 40
P28 91 62 79 66 / 40 60 50 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Sugden
SHORT TERM...Finch
LONG TERM...Ruthi
AVIATION...Ruthi
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
702 AM CDT Sun Sep 15 2013
...Updated Aviation Section...
.SHORT TERM...(Today and tonight)
ISSUED AT 403 AM CDT SUN SEP 15 2013
An upper level trough over the Rockies will continue to eject
minor waves into the plains today and tonight. Meanwhile, a
shortwave trough progressing southeastward across the upper midwest
will help push a fairly strong cold front into southwest Kansas
this afternoon. Thunderstorm chances are fairly good along
and ahead of the front; but these are not expected to be
severe given the lack of shear and marginal surface based CAPE.
The best chance of storms is along and southeast of a line from
Dodge City to Larned after 4 pm. Opted to go with a non-diurnal
temperature trend for today by using the 06Z RUC as a 1st guess,
then modifying the hourly temperatures that seemed too hot ahead
of the front. Temperatures should be falling in the afternoon from
Dodge City northward to interstate 70 as low level stratus invades
from the northern plains. Late afternoon temperatures may be in the
upper 60s around Wakeeney and in the lower 90s for areas southeast
of Dodge City around Medicine Lodge. For tonight, some elevated
showers and thunderstorm may persist through the nigh as upper
level troughing hangs back to the west over Colorado. However,
if the lower levels are stabilized too much by the deep cold
advection, then this activity may not pan out at all. Temperatures
should fall into the 50s to lower 60s by advection alone by
Tuesday morning with low stratus hanging tough.
.LONG TERM...(Monday through Saturday)
ISSUED AT 357 AM CDT SUN SEP 15 2013
There is considerable uncertainty in synoptic scale details in the
extended period with a blocky flow regime likely to persist in the
United States through the last week of September. Global scale
forcing is weak, and the numerical models exhibit considerable
spread, especially in the week two period. The Madden Julian
Oscillation is weak, but most of the global scale models do suggest
a low amplitude coherent signal in Phase 5 of the Wheeler-Hendon
Phase Space Diagram this week. However, the low amplitude of the
signal and the generally weak correlation with mid latitude weather
this time of the year provide little to increase confidence in the
extended forecast. Global relative angular momentum continues below
climatological values, and the recent spike in mountain torque has
ended. The net result is that there is little signal in the Global
Wind Oscillation to provide much guidance, either.
The upper level high over southeastern Alberta will break down and
progress east today and Monday as the upper low near 130W progresses
into the Pacific Northwest. The upper level trough in the northern
stream from near Lake Superior to South Dakota will continue to dig
into the long wave trough in the upper Midwest, and a cold front
will move across most of Kansas before becoming stationary tonight
near the Kansas/Oklahoma border this evening. Most of Kansas will be
under moist east flow Monday with considerable cloud cover, although
the cloudiness may break in the southwest corner of the state during
the afternoon. The cold trough over the Rockies will progress into
Kansas Monday as the block breaks down. Weak upward vertical motion
in a moist atmosphere will favor continued chances for showers and a
few thunderstorms Monday. Instability should be better in far
southwest Kansas near the old frontal zone, especially if breaks in
the cloudiness develop during the afternoon. A modest low level jet
with H8 winds around 30kts will develop Monday night as pressures
fall in the Northern Plains, and low level isentropic lifting will
favor shower and thunderstorm development during the nighttime
hours. The best isentropic lift will propagate into northern Kansas
after 06Z, and thunderstorm chances will decrease in southwest
Kansas.
The surface warm front will mix northward quickly after sunrise
Tuesday, and an elevated mixed layer will spread across western
Kansas during the day. Tuesday and Wednesday should be breezy and
warm with highs in the upper 80s and lower 90s in most areas. By
Wednesday, the jet streak near 170W will dig into the northern
Rockies and will progress slowly eastward Thursday and Friday. The
ECMWF and GEM are more progressive with the trough than the GFS and
develop a deeper closed cyclone than the GFS by 00Z Friday. Most of
the GEM ensemble members also are more progressive than the
deterministic GFS, as are many of the GFS ensemble members. The
preponderance of evidence supports a solution more similar to the
ECMWF later this week. A cold front will move into northwest Kansas
Wednesday evening and should progress across all of western Kansas
by late Thursday morning. Warm temperatures aloft and timing of the
frontal passage during the nighttime and early morning hours are not
favorable for much thunderstorm development along the boundary. Some
post-frontal development is possible Thursday as mid level
temperatures cool and western Kansas comes under the entrance region
of a jet streak.
Upper level ridging will build over Kansas Friday, and the next
upper level trough will dig into the northern Rockies Saturday. The
ECMWF closes off another cyclone over eastern Montana Sunday and
wallows a closed low into the central plains by Tuesday, while the
GFS and most if its ensemble members maintain a more open wave much
farther north than the ECMWF. Confidence is low with evolution of
the upper level trough. The ECMWF may be trending in the right
direction given the blocky flow in North America, but a few more
runs are needed before accepting the ECMWF solution.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
ISSUED AT 700 AM CDT SUN SEP 15 2013
A cold front will move across western Kansas today and should extend
from southeast Kansas to the central Texas Panhandle by Monday
morning. Southwest winds 10 to 15 knots will become north to
northeast at 10 to 15 knots following passage of the cold front.
Local visibilities 4-5 miles in mist can be expected around sunrise
today. Scattered clouds AOA 100 will prevail this morning, and
scattered cumulus clouds with bases near 060 will develop by late
morning. Ceilings 015 to 025 will spread southward behind the cold
front, reaching HYS around 1700Z and GCK and DDC after 0000Z.
Scattered thunderstorms will form along the front around 21Z near
DDC and move east. Upslope flow in eastern Colorado will favor
development of showers and thunderstorms that will weaken and
propagate into western Kansas this evening, reaching GCK around
0500Z and DDC and HYS after 0700Z.
Moist east to northeast upslope flow and stratus with bases 010-020
will persist Monday. An upper level trough will move from the
Rockies to western Kansas Monday and will provide enough upward
vertical motion to support scattered showers and a few
thunderstorms.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 85 58 73 63 / 30 40 40 30
GCK 81 57 72 61 / 20 30 40 30
EHA 84 57 78 62 / 30 30 40 40
LBL 86 58 77 62 / 30 30 40 40
HYS 76 57 71 62 / 20 30 30 40
P28 91 62 79 66 / 40 60 50 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Finch
LONG TERM...Ruthi
AVIATION...Ruthi
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
409 AM CDT Sun Sep 15 2013
...Updated for short term discussion...
.SHORT TERM...(Today and tonight)
ISSUED AT 403 AM CDT SUN SEP 15 2013
An upper level trough over the Rockies will continue to eject
minor waves into the plains today and tonight. Meanwhile, a
shortwave trough progressing southeastward across the upper midwest
will help push a fairly strong cold front into southwest Kansas
this afternoon. Thunderstorm chances are fairly good along
and ahead of the front; but these are not expected to be
severe given the lack of shear and marginal surface based CAPE.
The best chance of storms is along and southeast of a line from
Dodge City to Larned after 4 pm. Opted to go with a non-diurnal
temperature trend for today by using the 06Z RUC as a 1st guess,
then modifying the hourly temperatures that seemed too hot ahead
of the front. Temperatures should be falling in the afternoon from
Dodge City northward to interstate 70 as low level stratus invades
from the northern plains. Late afternoon temperatures may be in the
upper 60s around Wakeeney and in the lower 90s for areas southeast
of Dodge City around Medicine Lodge. For tonight, some elevated
showers and thunderstorm may persist through the nigh as upper
level troughing hangs back to the west over Colorado. However,
if the lower levels are stabilized too much by the deep cold
advection, then this activity may not pan out at all. Temperatures
should fall into the 50s to lower 60s by advection alone by
Tuesday morning with low stratus hanging tough.
.LONG TERM...(Monday through Saturday)
ISSUED AT 357 AM CDT SUN SEP 15 2013
There is considerable uncertainty in synoptic scale details in the
extended period with a blocky flow regime likely to persist in the
United States through the last week of September. Global scale
forcing is weak, and the numerical models exhibit considerable
spread, especially in the week two period. The Madden Julian
Oscillation is weak, but most of the global scale models do suggest
a low amplitude coherent signal in Phase 5 of the Wheeler-Hendon
Phase Space Diagram this week. However, the low amplitude of the
signal and the generally weak correlation with mid latitude weather
this time of the year provide little to increase confidence in the
extended forecast. Global relative angular momentum continues below
climatological values, and the recent spike in mountain torque has
ended. The net result is that there is little signal in the Global
Wind Oscillation to provide much guidance, either.
The upper level high over southeastern Alberta will break down and
progress east today and Monday as the upper low near 130W progresses
into the Pacific Northwest. The upper level trough in the northern
stream from near Lake Superior to South Dakota will continue to dig
into the long wave trough in the upper Midwest, and a cold front
will move across most of Kansas before becoming stationary tonight
near the Kansas/Oklahoma border this evening. Most of Kansas will be
under moist east flow Monday with considerable cloud cover, although
the cloudiness may break in the southwest corner of the state during
the afternoon. The cold trough over the Rockies will progress into
Kansas Monday as the block breaks down. Weak upward vertical motion
in a moist atmosphere will favor continued chances for showers and a
few thunderstorms Monday. Instability should be better in far
southwest Kansas near the old frontal zone, especially if breaks in
the cloudiness develop during the afternoon. A modest low level jet
with H8 winds around 30kts will develop Monday night as pressures
fall in the Northern Plains, and low level isentropic lifting will
favor shower and thunderstorm development during the nighttime
hours. The best isentropic lift will propagate into northern Kansas
after 06Z, and thunderstorm chances will decrease in southwest
Kansas.
The surface warm front will mix northward quickly after sunrise
Tuesday, and an elevated mixed layer will spread across western
Kansas during the day. Tuesday and Wednesday should be breezy and
warm with highs in the upper 80s and lower 90s in most areas. By
Wednesday, the jet streak near 170W will dig into the northern
Rockies and will progress slowly eastward Thursday and Friday. The
ECMWF and GEM are more progressive with the trough than the GFS and
develop a deeper closed cyclone than the GFS by 00Z Friday. Most of
the GEM ensemble members also are more progressive than the
deterministic GFS, as are many of the GFS ensemble members. The
preponderance of evidence supports a solution more similar to the
ECMWF later this week. A cold front will move into northwest Kansas
Wednesday evening and should progress across all of western Kansas
by late Thursday morning. Warm temperatures aloft and timing of the
frontal passage during the nighttime and early morning hours are not
favorable for much thunderstorm development along the boundary. Some
post-frontal development is possible Thursday as mid level
temperatures cool and western Kansas comes under the entrance region
of a jet streak.
Upper level ridging will build over Kansas Friday, and the next
upper level trough will dig into the northern Rockies Saturday. The
ECMWF closes off another cyclone over eastern Montana Sunday and
wallows a closed low into the central plains by Tuesday, while the
GFS and most if its ensemble members maintain a more open wave much
farther north than the ECMWF. Confidence is low with evolution of
the upper level trough. The ECMWF may be trending in the right
direction given the blocky flow in North America, but a few more
runs are needed before accepting the ECMWF solution.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
ISSUED AT 1259 AM CDT SUN SEP 15 2013
A cold front will approach KHYS around 18z, KGCK around 21z and
KDDC by 22z. Thunderstorms may affect KDDC along the front between
22-24z. Otherwise, south winds will shift to the southwest at
10-15 kts by 15z and then north-northeast at 12-17kts behind the
cold front. IFR CIGS may develop at KDDC by 04z as low level
upslope flow develops.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 87 61 73 63 / 30 40 40 30
GCK 81 58 72 61 / 20 30 40 30
EHA 82 60 78 62 / 30 30 40 40
LBL 85 63 77 62 / 30 30 40 40
HYS 82 58 71 62 / 10 30 30 40
P28 93 65 79 66 / 40 40 50 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Finch
LONG TERM...Ruthi
AVIATION...Finch
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1146 PM MDT SAT SEP 14 2013
.UPDATE...
ISSUED AT 757 PM MDT SAT SEP 14 2013
JUST COMPLETED AN UPDATE. MAIN CHANGE WAS READJUST THE POP FIELD.
MAJORITY OF THE MODELS AND FORECAST WAS EMPHASIZING THE SOUTHEAST
PORTION OF THE AREA. PER MESOANALYSIS AND MODEL DATA ALONG WITH
REALITY MAIN AREA OF THUNDERSTORMS LOOKS TO INITIALLY BE THE
NORTHWEST CORNER AND THEN SPREADING EAST ACROSS THE REMAINDER OF
THE NORTHERN TIER OF COUNTIES. THIS IS WHERE PREFRONTAL SURFACE
TROUGH AND THEN COLD FRONT WILL COINCIDE WITH THE DEEPEST MOISTURE
AND MID/UPPER LEVEL LIFT.
SOUTHEAST PORTION OF THE AREA LOOKS CAPPED. HOWEVER THAT SHOULD
CHANGE BY LATER TONIGHT. THE HRRR FOLLOWED BY THE GFS WAS CATCHING
THE PRECIPITATION FIELD THE BEST. ALSO ADJUSTED THE SKY COVER AND
WIND PER LATEST TRENDS AND MESOSCALE MODEL DATA.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 250 PM MDT SAT SEP 14 2013
A SURFACE LEE TROUGH IS DEEPENING AND MOVING EASTWARD ACROSS THE
FORECAST AREA THIS AFTERNOON IN RESPONSE TO A COUPLE OF WEAK SHORT
WAVES ROTATING AROUND THE MAIN UPPER LOW THAT IS VERY SLOW TO LIFT
OUT OF THE INTERMOUNTAIN REGION. THIS SURFACE TROUGH IS IN ADVANCE
OF A COLD FRONT THAT PUSHES SOUTHWARD INTO THE REGION ON SUNDAY.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED TO DEVELOP
ALONG AND EAST OF THE SURFACE TROUGH THIS LATE THIS AFTERNOON AND
EVENING ALONG WITH WITH A FEW STORMS DEVELOPING OVER THE FRONT RANGE
MOVING EAST OVER THE PLAINS THAT ARE EXPECTED TO DIMINISH THIS
EVENING. SCATTERED STORMS WILL DEVELOP AGAIN SUNDAY AFTERNOON
MAINLY IN THE VICINITY OF THE FRONT AS IT PUSHES SOUTH ACROSS THE
FORECAST AREA. LIGHT TO MODERATE RAINFALL IS EXPECTED WITH THESE
STORMS...WHICH COULD PRODUCE LOCALIZED AREAS OF FLOWING WATER IN
STREAM BEDS THAT ARE EITHER NORMALLY DRY OR STILL HAVE SOME WATER IN
THEM REMAINING FROM THE RECENT HEAVY RAINFALLS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 250 PM MDT SAT SEP 14 2013
SUNDAY NIGHT THROUGH MONDAY NIGHT NUMEROUS UPPER LEVEL SHORT WAVE
TROUGHS WILL MOVE OVER THE AREA. THE ENVIRONMENT WILL HAVE SOME
CONVECTIVE INSTABILITY AND THE PLUME OF SUBTROPICAL MOISTURE WILL
PERSIST OVER THE AREA UNTIL MONDAY NIGHT. THE STRONGEST UPPER LEVEL
TROUGH WITH THE BEST INSTABILITY WILL MOVE OVER THE AREA SUNDAY
NIGHT. DIFFICULT TO BE TOO EXCITED ABOUT PRECIP. CHANCES GIVEN THE
LIFT ASSOCIATED WITH THE TROUGH IS ON THE WEAKER SIDE. HOWEVER THE
LAST FEW DAYS HAVE HAD GOOD STORM DEVELOPMENT WITH RATHER BENIGN
LOOKING SHORT WAVE TROUGHS. MONDAY THE CONVECTIVE INSTABILITY
DIMINISHES SOME AND THE SHORT WAVE TROUGHS LOOK WEAKER...SO WILL
HAVE LOWER PRECIP. CHANCES AS A RESULT...WITH CHANCES ENDING FROM
WEST TO EAST AS DRIER AIR MOVES IN MONDAY EVENING. MEANWHILE THE COLD
FRONT FROM SUNDAY WILL MOVE IN FROM THE WEST AS A WARM FRONT AND
STALL OVER THE AREA MONDAY NIGHT. SLOW STORM MOTIONS WILL LEAD TO A
THREAT FOR HEAVY RAINFALL.
TUESDAY THROUGH SATURDAY THE NEXT BEST CHANCE FOR RAINFALL WILL BE
WEDNESDAY NIGHT AS A COLD FRONT MOVES THROUGH THE AREA WHILE AN
UPPER LEVEL LOW MOVES ACROSS THE NORTHERN PLAINS. WITH THE TRI-
STATE AREA BEING ON THE FAR SOUTHERN SIDE OF THE LOW...PRECIP.
CHANCES WILL BE CONFINED TO THE FRONTAL PASSAGE. BEHIND THE UPPER
LEVEL LOW A RIDGE WILL BUILD OVER THE AREA FOR THE WEEKEND.
TEMPERATURES FOR THE PERIOD WILL START OUT ABOVE NORMAL AS A WARM
FRONT MOVES THROUGH THE AREA FROM THE WEST TUESDAY. NEAR NORMAL
TEMPERATURES RETURN BEHIND THE COLD FRONT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1141 PM MDT SAT SEP 14 2013
CHAOTIC/VARIABLE CONDITIONS EXPECTED THROUGH THE PERIOD. INITIALLY
EXPECT THUNDERSTORMS TO AFFECT THE KMCK WITH CONDITIONS NEARING
MVFR IF A STRONG ENOUGH THUNDERSTORM COMES ACROSS. INITIALLY WINDS
WILL BE VARIABLE DUE TO THUNDERSTORM OUTFLOW AND THE PASSAGE OF
THE PREFRONTAL TROUGH BEFORE A STRONGER WIND SHIFT WITH THAT FRONT.
FRONT WILL MOVE THROUGH THE TAF SITES IN THE 12Z TO 14Z TIME FRAME
WITH GUSTY WINDS BEHIND IT UNTIL EARLY AFTERNOON.
BEHIND THE FRONT AT LEAST MVFR CEILINGS IN STRATUS ARE EXPECTED.
MODEL GUIDANCE IS SIMILAR TO WHAT IS UPSTREAM BEHIND THE FRONT.
ALTHOUGH SOME MODEL OUTPUT HAS CEILINGS BREIFLY GOING INTO IFR.
CEILINGS WILL RISE AND WINDS WILL DECREASE IN THE AFTERNOON. AT
THIS TIME IT LOOKS LIKE MVFR CEILINGS WILL LAST AT KGLD UNTIL THE
END OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...JTL
LONG TERM...JTL
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
708 PM EDT MON SEP 16 2013
.AVIATION...
//DISCUSSION...
HIGH PRESSURE WILL BRING CLEAR SKIES THIS EVENING INTO TONIGHT WITH
LIGHT WINDS. EASTERLY FLOW AROUND SOUTHERN EDGE OF THIS HIGH AS THE
POTENTIAL TO BRING LOW LEVEL MOISTURE BACK FROM THE GREAT LAKES INTO
THE I-94 CORRIDOR BY EARLY TUESDAY MORNING...AND WILL MAINTAIN THE
IDEA OF SCT-BKN MVFR STRATUS FOR THIS FORECAST PACKAGE AS LATEST
NAM, RAP AND GFS ALL SUGGEST THIS POTENTIAL.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET DISSIPATING THIS
AFTERNOON
* MEDIUM CONFIDENCE IN CEILINGS BELOW 5000 FEET DEVELOPING EARLY
TUESDAY MORNING.
&&
.PREV DISCUSSION...ISSUED 343 PM EDT MON SEP 16 2013
SHORT TERM...TONIGHT
SKIES ARE SLOWLY CLEARING OUT THIS AFTERNOON...AS NORTHEAST WINDS
OFF LAKE HURON SUBSIDE AND INCREASING BOUNDARY LAYER DEPTH TAPS INTO
MUCH DRIER AIR...SEE 12Z APX AND DTX SOUNDINGS. 1030+ MB SURFACE
HIGH LOOKS TO BE PARKED OVER SAGINAW BAY/NORTHERN THUMB REGION
AROUND MIDNIGHT...PROVIDING VERY GOOD RADIATING CONDITIONS...AND
LOOKING AT MINS IN THE MID 30S TO AROUND 40 DEGREES (PER INHERITED
GRIDS)...AS DEW PTS SHOULD SETTLE IN THAT RANGE TOWARD SUNSET. WILL
GO AHEAD AND ISSUE A FROST ADVISORY FOR AREAS ALONG AND NORTH OF
I-69 DUE TO THE CLOSER PROXIMITY TO THE SURFACE HIGH. FARTHER
SOUTH...TEMPS EXPECTED TO HOVER JUST A COUPLE DEGREES WARMER WITH
LIGHT EASTERLY WIND AND SLIGHTLY WARMER RETURN FLOW...ALONG WITH
LAKE ERIE STRATUS LIKELY DEVELOPING (SEE NAM 925 MB RH FIELDS)
TOWARD SUNRISE...IMPACTING AT LEAST WAYNE/MONROE COUNTIES.
LONG TERM...
RIDGING OVER THE WEST CENTRAL U.S. IS DEAMPLIFYING DUE TO THE
GENERAL PATTERN OF HEIGHT FALLS ACROSS CENTRAL CANADA. THIS WILL
HELP ENSURE A CONTINUANCE OF THEP ROGRESSIVE PATTERN ALOFT AS A
FRESH BATCH OF ENERGY EMERGES FROM THE EAST PACIFIC OVERNIGHT. THE
SUBSEQUENT EASTWARD PUSH WILL FORCE THE RESIDENT CANADIAN HIGH OVER
THE STATE TO TRANSLATE TO THE NEW ENGLAND COAST DURING THE NEXT 24
HOURS RESULTING IN DEVELOPING WARM ADVECTION WITHIN EMERGING RETURN
FLOW. WHEN CONSIDERED ALONG WITH ANOTHER DAY OF AIRMASS
MODIFICATION, HIGH TEMPERATURES FOR TUESDAY WILL EASILY INCREASE
INTO THE 65 TO 70 DEGREE RANGE, SEVERAL DEGREES WARMER THAN TODAY`S
VALUES.
DEEP SOUTHWEST FLOW WILL THEN PERSIST THROUGH THE END OF THE
WEEK AS THE AFOREMENTIONED WEST COAST ENERGY LIFTS TOWARD HUDSON
BAY, UNDERGOING ADDITIONAL AMPLIFICATION AS IT DOES SO. DEWPOINTS
WILL SUBSEQUENTLY RISE THROUGH THE 50S ON WEDNESDAY AND INTO THE 60S
THURSDAY WHILE TEMPERATURES LIKEWISE MAKE A STEADY UPWARD CLIMB
TOWARD 80 DEGREES, OR SLIGHTLY ABOVE MID-SEPTEMBER AVERAGE VALUES.
INCREASING MOISTURE QUALITY WITHIN THE NEW WEAKLY CONDITIONALLY
UNSTABLE AIRMASS WILL WARRANT CONTINUANCE OF THE INERHITED CHANCE
POP FOR MUCH OF THE WED NIGHT THROUGH THURSDAY PERIOD AS WEAK
ISENTROPIC ASCENT BUILDS INTO THE GREAT LAKES BENEATH RATHER SHODDY
DYNAMICS ALOFT.
FORCING WILL DRAMATICALLY IMPROVE ON FRIDAY AS A RESULT OF PROGGED
WAVE PHASING TAKING PLACE JUST NORTH OF THE U.S./CANADA BORDER. THIS
WILL RESULT IN A QUICK INTENSIFICATION OF THE UPPER JET AND
SUBSEQUENT MATURATION OF A DEEP-TROPOSPHERIC JET/FRONT STRUCTURE
CHARACTERIZED BY DEEP MOIST ISENTROPIC ASCENT, WELL-DEFINED H5-H3
FGEN WRAPPING BENEATH THE RIGHT ENTRANCE, AND SUSTAINED BOUNDARY
PARALLEL MOISTURE TRANSPORT ALONG THE LOWER TROPOSPHERIC PORTION OF
THE BOUNDARY. CONSEQUENTLY, CONFIDENCE IN A BAND OF RAINFALL
ALIGNING ALONG THE COLD FRONT IS RATHER HIGH, SO MADE THE JUMP TO
HIGH LIKELY POPS FOR FRIDAY.
MARINE...
WINDS OVER THE CENTRAL GREAT LAKES ARE DIMINISHING THIS AFTERNOON AS
HIGH PRESSURE BUILDS OVER LAKE HURON...AND EXPECT LIGHT WINDS
TONIGHT OVER THE ENTIRE AREA. LIGHT EASTERLY WIND AND POCKET OF COLD
AIR OVER LAKE ERIE WILL BRING THE CONCERN FOR A WATERSPOUT...BUT
INVERSION HEIGHTS APPEAR TO BE TOO LOW. RETURN FLOW AROUND THE HIGH
TOMORROW WILL LEAD TO SLOWLY INCREASING SOUTHERLY WINDS INTO TUESDAY
NIGHT...BUT WIND SPEEDS STILL ONLY TOPPING OUT AROUND 15 KNOTS...AS
MILDER AIR LEADS TO MORE STABLE LOW LEVEL PROFILES.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...FROST ADVISORY...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054-MIZ055-MIZ060-
MIZ061-MIZ062-MIZ063...FROM 3 AM TUESDAY TO 8 AM TUESDAY.
LAKE HURON...
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS
FROM PORT AUSTIN TO HARBOR BEACH...UNTIL 10 PM MONDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO PORT
HURON...UNTIL 4 AM TUESDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....99
SHORT TERM...SF
LONG TERM....JVC
MARINE.......SF
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
132 PM EDT SUN SEP 15 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 515 AM EDT SUN SEP 15 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OVER THE NRN ROCKIES
AND A TROUGH OVER HUDSON BAY RESULTING IN CYCLONIC WNW FLOW THROUGH
THE NRN GREAT LAKES. A SHORTWAVE TROUGH OVER MN AND AREA OF UPPER
LEVEL DIV WITH THE RIGHT ENTRANCE OF THE 250-300 MB JET OVER NRN
ONTARIO SUPPORTED A LARGE AREA OF RAIN FROM SE MN THROUGH UPPER MI
AND WI. THE STRONGEST 700-500 MB QVECTOR CONV AND HEAVIER PCPN
REMAINED TO THE SOUTH OVER WI. HOWEVER...300K-305K ISENTROPIC LIFT
EXTENDING INTO UPPER MI AHEAD OF THE SFC TROUGH FROM NW IA INTO NW
WI HAS HELPED BRING LIGHT RAIN THROUGH THE CWA. WINDS HAD VEERED
SHARPLY TO THE NE AND INCREASED TO 15 TO 25 KNOTS OVER NRN LAKE
SUPERIOR BEHIND A COLD FRONT SAGGING INTO UPPER MI.
TODAY...RADAR/SATELLITE TRENDS AND MODELS SUGGEST THAT THE SHORTWAVE AND
AREA OF WIDESPREAD RAIN WILL CONTINUE TO MOVE OFF TO THE SOUTHEAST
AND END BY AFTERNOON. HOWEVER...THE CYCLONIC NNE FLOW AND 850 MB
TEMPS FALLING INTO THE 2C TO 4C RANGE BEFORE THE DEEPER MOISTURE
DEPARTS WILL SUPPORT SOME LAKE ENHANCED RAIN/DRIZZLE INTO N CNTRL
UPPER MI ESPECIALLY OVER THE HIGHER TERRAIN WHERE LOW LEVEL UPSLOPE
FLOW IS STRONGEST. ONCE THE DEEP MOISTURE QUICKLY MOVES OUT AROUND
18Z...THE REMAINING PCPN SHOULD END ALONG WITH DIMINISHING CLOUD
COVER.
TONIGHT...HIGH PRESSURE OVER NRN MANITOBA WHERE SOME TEMPS HAVE
FALLEN INTO THE MID AND UPPER 20S...WILL BUILD INTO UPPER MI
BRINGING CLEARING SKIES AND DIMINISHING WINDS. WITH PWAT VALUES
FALLING CLOSE TO 0.3 INCHES...FAVORABLE RADIATIONAL COOLING WILL
ALLOW TEMPS TO DROP INTO THE LOWER 30S OVER MUCH OF THE INTERIOR
WEST HALF OF UPPER MI WHERE A FROST ADVISORY WAS ISSUED. FARTHER
EAST...LINGERING NE WINDS WILL BE STRONG ENOUGH TO KEEP TEMPS FROM
DROPPING OFF AS MUCH.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 414 AM EDT SUN SEP 15 2013
500MB RIDGE AND SFC PRESSURE WILL CONTROL THE FIRST PORTION OF THE
LONG TERM FORECAST PERIOD. THIS RIDGE WILL MOVE FROM THE NORTHERN
PLAINS ON MONDAY MORNING INTO THE OHIO VALLEY BY TUESDAY NIGHT.
EXPECT UPPER MICHIGAN WEATHER TO BE QUITE PLEASANT MONDAY AND
TUESDAY. ON MONDAY 850MB TEMPS WILL DIP TO AROUND 3-5C...AND WINDS
WILL BE NORTHERLY OFF LAKE SUPERIOR. KEPT HIGHS IN THE UPPER 50S AND
60S ACCORDINGLY. TUESDAY 850MB TEMPS WILL CLIMB TO THE 6-10C RANGE
AND SFC WINDS WILL SWING TO THE SOUTH...RAISING AFTERNOON HIGHS INTO
THE UPPER 60S AND LOW 70S...WHICH IS NORMAL FOR THIS TIME OF YEAR.
MEANWHILE...A DEEP 500MB LOW PRESSURE TROUGH MAKES ITS WAY ONSHORE
OVER THE NORTHWESTERN UNITED STATES. THE ASSOCIATED SFC LOW DEVELOPS
OVER MONTANA BY TUESDAY AFTERNOON...AND STRONG MOISTURE
TRANSPORT BRINGS PWATS UP TO 160 PERCENT OF NORMAL INTO WESTERN
UPPER MICHIGAN BY 06Z WEDNESDAY. AS THE LOW MOVES EASTWARD INTO THE
DAKOTAS THROUGH WEDNESDAY NIGHT...EXPECT THIS AREA OF STRONGER
MOISTURE ADVECTION TO MOVE EASTWARD THROUGH THE CWA. WITH A WEAK
SHORTWAVE FLATTENING THE EXITING RIDGE...AND AREA OF MOISTURE
ADVECTION FEEL THAT CHANCE TO SLIGHT CHANCE POPS ARE WARRANTED
ACROSS UPPER MICHIGAN FOR TUESDAY NIGHT AND WEDNESDAY-WITH HIGHER
POPS LOCATED FURTHER SOUTH NEAR THE BETTER FORCING. THE BEST
INSTABILITY ARRIVES LATER WEDNESDAY MORNING INTO THE AFTERNOON...SO
LEFT THUNDER OUT UNTIL THESE TIMES.
THURSDAY INTO SUNDAY WE DEAL WITH THE ARRIVAL OF THE ACTUAL
SFC/UPPER LEVEL LOW PRESSURE SYSTEM...WHICH MODELS CURRENTLY HAVE
TRAVERSING ACROSS THE UPPER GREAT LAKES. AS USUAL...MODEL
DIFFERENCES WILL GREATLY IMPACT THE FORECAST FOR THE WEEKEND...WITH
THE ECMWF/GEM BRINGING A CUT OFF 500MB LOW ACROSS NORTHEASTERN
MINNESOTA/NORTHERN ONTARIO BY FRIDAY AFTERNOON. THE GFS HAS A
NEUTRALLY TILTED TROUGH REACHING MINNESOTA AROUND THE SAME
TIME...WITH THE SURFACE LOW OVER ONTARIO JUST SOUTH OF JAMES BAY.
DESPITE DIFFERENCES...CAN AGREE THAT THIS WILL LIKELY BE A SOGGY END
TO THE WEEK...WITH MODELS PROJECTING PWATS 160-210 PERCENT OF
NORMAL. NOT GOING TO GET CUTE WITH THE GRIDS AT THIS POINT...BUT
WILL USE THE WPC DAY 3-7 FRONTS/PRESSURE LOCATIONS AS A GUIDE UNTIL
GREATER CONSISTENCY IS ACHIEVED. THIS PUTS THE SFC LOW DIRECTLY OVER
UPPER MICHIGAN ON FRIDAY MORNING...AND OVER QUEBEC BY SATURDAY
AFTERNOON.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 131 PM EDT SUN SEP 15 2013
EXPECT A GRADUAL TRANSITION TO VFR CONDITIONS LATER THIS
AFTERNOON WITH THE APPROACH OF HIGH PRESSURE AND THE ARRIVAL OF
DRIER AIR. A STEADY N WIND WILL DIMINISH BY THIS EVENING WITH THE
CLOSER APPROACH OF THE HIGH AND LOSS OF OF DAYTIME HEATING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 515 AM EDT SUN SEP 15 2013
NE WINDS UP TO 30 KNOTS TODAY ARE EXPECTED BEHIND A COLD FRONT
MOVING THROUGH LAKE SUPERIOR EARLY THIS MORNING. WINDS WILL DIMINISH
LATE THIS AFTERNOON AND TONIGHT AS HIGH PRESSURE BUILDS INTO THE
AREA. WITH THE HIGH DOMINATING THE REGION MON...WINDS WILL REMAIN
BELOW 20 KNOTS. AS THE HIGH SHIFTS TO THE EAST...SRLY WINDS UP TO
20 KNOTS ARE EXPECTED FROM TUE INTO WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FROST ADVISORY FROM 2 AM EDT /1 AM CDT/ TO 9 AM EDT /8 AM CDT/
MONDAY FOR MIZ002-004-005-009>011-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...MCD
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
738 AM EDT SUN SEP 15 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 515 AM EDT SUN SEP 15 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OVER THE NRN ROCKIES
AND A TROUGH OVER HUDSON BAY RESULTING IN CYCLONIC WNW FLOW THROUGH
THE NRN GREAT LAKES. A SHORTWAVE TROUGH OVER MN AND AREA OF UPPER
LEVEL DIV WITH THE RIGHT ENTRANCE OF THE 250-300 MB JET OVER NRN
ONTARIO SUPPORTED A LARGE AREA OF RAIN FROM SE MN THROUGH UPPER MI
AND WI. THE STRONGEST 700-500 MB QVECTOR CONV AND HEAVIER PCPN
REMAINED TO THE SOUTH OVER WI. HOWEVER...300K-305K ISENTROPIC LIFT
EXTENDING INTO UPPER MI AHEAD OF THE SFC TROUGH FROM NW IA INTO NW
WI HAS HELPED BRING LIGHT RAIN THROUGH THE CWA. WINDS HAD VEERED
SHARPLY TO THE NE AND INCREASED TO 15 TO 25 KNOTS OVER NRN LAKE
SUPERIOR BEHIND A COLD FRONT SAGGING INTO UPPER MI.
TODAY...RADAR/SATELLITE TRENDS AND MODELS SUGGEST THAT THE SHORTWAVE AND
AREA OF WIDESPREAD RAIN WILL CONTINUE TO MOVE OFF TO THE SOUTHEAST
AND END BY AFTERNOON. HOWEVER...THE CYCLONIC NNE FLOW AND 850 MB
TEMPS FALLING INTO THE 2C TO 4C RANGE BEFORE THE DEEPER MOISTURE
DEPARTS WILL SUPPORT SOME LAKE ENHANCED RAIN/DRIZZLE INTO N CNTRL
UPPER MI ESPECIALLY OVER THE HIGHER TERRAIN WHERE LOW LEVEL UPSLOPE
FLOW IS STRONGEST. ONCE THE DEEP MOISTURE QUICKLY MOVES OUT AROUND
18Z...THE REMAINING PCPN SHOULD END ALONG WITH DIMINISHING CLOUD
COVER.
TONIGHT...HIGH PRESSURE OVER NRN MANITOBA WHERE SOME TEMPS HAVE
FALLEN INTO THE MID AND UPPER 20S...WILL BUILD INTO UPPER MI
BRINGING CLEARING SKIES AND DIMINISHING WINDS. WITH PWAT VALUES
FALLING CLOSE TO 0.3 INCHES...FAVORABLE RADIATIONAL COOLING WILL
ALLOW TEMPS TO DROP INTO THE LOWER 30S OVER MUCH OF THE INTERIOR
WEST HALF OF UPPER MI WHERE A FROST ADVISORY WAS ISSUED. FARTHER
EAST...LINGERING NE WINDS WILL BE STRONG ENOUGH TO KEEP TEMPS FROM
DROPPING OFF AS MUCH.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 414 AM EDT SUN SEP 15 2013
500MB RIDGE AND SFC PRESSURE WILL CONTROL THE FIRST PORTION OF THE
LONG TERM FORECAST PERIOD. THIS RIDGE WILL MOVE FROM THE NORTHERN
PLAINS ON MONDAY MORNING INTO THE OHIO VALLEY BY TUESDAY NIGHT.
EXPECT UPPER MICHIGAN WEATHER TO BE QUITE PLEASANT MONDAY AND
TUESDAY. ON MONDAY 850MB TEMPS WILL DIP TO AROUND 3-5C...AND WINDS
WILL BE NORTHERLY OFF LAKE SUPERIOR. KEPT HIGHS IN THE UPPER 50S AND
60S ACCORDINGLY. TUESDAY 850MB TEMPS WILL CLIMB TO THE 6-10C RANGE
AND SFC WINDS WILL SWING TO THE SOUTH...RAISING AFTERNOON HIGHS INTO
THE UPPER 60S AND LOW 70S...WHICH IS NORMAL FOR THIS TIME OF YEAR.
MEANWHILE...A DEEP 500MB LOW PRESSURE TROUGH MAKES ITS WAY ONSHORE
OVER THE NORTHWESTERN UNITED STATES. THE ASSOCIATED SFC LOW DEVELOPS
OVER MONTANA BY TUESDAY AFTERNOON...AND STRONG MOISTURE
TRANSPORT BRINGS PWATS UP TO 160 PERCENT OF NORMAL INTO WESTERN
UPPER MICHIGAN BY 06Z WEDNESDAY. AS THE LOW MOVES EASTWARD INTO THE
DAKOTAS THROUGH WEDNESDAY NIGHT...EXPECT THIS AREA OF STRONGER
MOISTURE ADVECTION TO MOVE EASTWARD THROUGH THE CWA. WITH A WEAK
SHORTWAVE FLATTENING THE EXITING RIDGE...AND AREA OF MOISTURE
ADVECTION FEEL THAT CHANCE TO SLIGHT CHANCE POPS ARE WARRANTED
ACROSS UPPER MICHIGAN FOR TUESDAY NIGHT AND WEDNESDAY-WITH HIGHER
POPS LOCATED FURTHER SOUTH NEAR THE BETTER FORCING. THE BEST
INSTABILITY ARRIVES LATER WEDNESDAY MORNING INTO THE AFTERNOON...SO
LEFT THUNDER OUT UNTIL THESE TIMES.
THURSDAY INTO SUNDAY WE DEAL WITH THE ARRIVAL OF THE ACTUAL
SFC/UPPER LEVEL LOW PRESSURE SYSTEM...WHICH MODELS CURRENTLY HAVE
TRAVERSING ACROSS THE UPPER GREAT LAKES. AS USUAL...MODEL
DIFFERENCES WILL GREATLY IMPACT THE FORECAST FOR THE WEEKEND...WITH
THE ECMWF/GEM BRINGING A CUT OFF 500MB LOW ACROSS NORTHEASTERN
MINNESOTA/NORTHERN ONTARIO BY FRIDAY AFTERNOON. THE GFS HAS A
NEUTRALLY TILTED TROUGH REACHING MINNESOTA AROUND THE SAME
TIME...WITH THE SURFACE LOW OVER ONTARIO JUST SOUTH OF JAMES BAY.
DESPITE DIFFERENCES...CAN AGREE THAT THIS WILL LIKELY BE A SOGGY END
TO THE WEEK...WITH MODELS PROJECTING PWATS 160-210 PERCENT OF
NORMAL. NOT GOING TO GET CUTE WITH THE GRIDS AT THIS POINT...BUT
WILL USE THE WPC DAY 3-7 FRONTS/PRESSURE LOCATIONS AS A GUIDE UNTIL
GREATER CONSISTENCY IS ACHIEVED. THIS PUTS THE SFC LOW DIRECTLY OVER
UPPER MICHIGAN ON FRIDAY MORNING...AND OVER QUEBEC BY SATURDAY
AFTERNOON.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 737 AM EDT SUN SEP 15 2013
SIMILAR TO UPSTREAM TRENDS AT CMX...THE PASSAGE OF A COLD FRONT N-S
THIS MORNING WILL BRING A SHARP WSHFT TO THE NNE AT SAW/IWD AND BRING
IFR CIGS AS A SHALLOW COLD WEDGE FOLLOWS THIS FROPA IN THE PRESENCE
OF SOME -SHRA. EXPECT THE LOWEST IFR CIGS AT SAW/IWD WHERE THE N WIND
PRESENTS THE GREATEST UPSLOPE COMPONENT. EXPECT A GRADUAL TRANSITION
TO VFR CONDITIONS IN THE AFTERNOON WITH THE APPROACH OF HIGH PRESSURE
AND THE ARRIVAL OF DRIER AIR. A STEADY NORTH WIND WILL DIMINISH BY THIS
EVENING WITH THE CLOSER APPROACH OF THE HIGH AND LOSS OF OF DAYTIME
HEATING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 515 AM EDT SUN SEP 15 2013
NE WINDS UP TO 30 KNOTS TODAY ARE EXPECTED BEHIND A COLD FRONT
MOVING THROUGH LAKE SUPERIOR EARLY THIS MORNING. WINDS WILL DIMINISH
LATE THIS AFTERNOON AND TONIGHT AS HIGH PRESSURE BUILDS INTO THE
AREA. WITH THE HIGH DOMINATING THE REGION MON...WINDS WILL REMAIN
BELOW 20 KNOTS. AS THE HIGH SHIFTS TO THE EAST...SRLY WINDS UP TO
20 KNOTS ARE EXPECTED FROM TUE INTO WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FROST ADVISORY FROM 2 AM EDT /1 AM CDT/ TO 9 AM EDT /8 AM CDT/
MONDAY FOR MIZ002-004-005-009>011-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...MCD
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
517 AM EDT SUN SEP 15 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 515 AM EDT SUN SEP 15 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OVER THE NRN ROCKIES
AND A TROUGH OVER HUDSON BAY RESULTING IN CYCLONIC WNW FLOW THROUGH
THE NRN GREAT LAKES. A SHORTWAVE TROUGH OVER MN AND AREA OF UPPER
LEVEL DIV WITH THE RIGHT ENTRANCE OF THE 250-300 MB JET OVER NRN
ONTARIO SUPPORTED A LARGE AREA OF RAIN FROM SE MN THROUGH UPPER MI
AND WI. THE STRONGEST 700-500 MB QVECTOR CONV AND HEAVIER PCPN
REMAINED TO THE SOUTH OVER WI. HOWEVER...300K-305K ISENTROPIC LIFT
EXTENDING INTO UPPER MI AHEAD OF THE SFC TROUGH FROM NW IA INTO NW
WI HAS HELPED BRING LIGHT RAIN THROUGH THE CWA. WINDS HAD VEERED
SHARPLY TO THE NE AND INCREASED TO 15 TO 25 KNOTS OVER NRN LAKE
SUPERIOR BEHIND A COLD FRONT SAGGING INTO UPPER MI.
TODAY...RADAR/SATELLITE TRENDS AND MODELS SUGGEST THAT THE SHORTWAVE AND
AREA OF WIDESPREAD RAIN WILL CONTINUE TO MOVE OFF TO THE SOUTHEAST
AND END BY AFTERNOON. HOWEVER...THE CYCLONIC NNE FLOW AND 850 MB
TEMPS FALLING INTO THE 2C TO 4C RANGE BEFORE THE DEEPER MOISTURE
DEPARTS WILL SUPPORT SOME LAKE ENHANCED RAIN/DRIZZLE INTO N CNTRL
UPPER MI ESPECIALLY OVER THE HIGHER TERRAIN WHERE LOW LEVEL UPSLOPE
FLOW IS STRONGEST. ONCE THE DEEP MOISTURE QUICKLY MOVES OUT AROUND
18Z...THE REMAINING PCPN SHOULD END ALONG WITH DIMINISHING CLOUD
COVER.
TONIGHT...HIGH PRESSURE OVER NRN MANITOBA WHERE SOME TEMPS HAVE
FALLEN INTO THE MID AND UPPER 20S...WILL BUILD INTO UPPER MI
BRINGING CLEARING SKIES AND DIMINISHING WINDS. WITH PWAT VALUES
FALLING CLOSE TO 0.3 INCHES...FAVORABLE RADIATIONAL COOLING WILL
ALLOW TEMPS TO DROP INTO THE LOWER 30S OVER MUCH OF THE INTERIOR
WEST HALF OF UPPER MI WHERE A FROST ADVISORY WAS ISSUED. FARTHER
EAST...LINGERING NE WINDS WILL BE STRONG ENOUGH TO KEEP TEMPS FROM
DROPPING OFF AS MUCH.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 414 AM EDT SUN SEP 15 2013
500MB RIDGE AND SFC PRESSURE WILL CONTROL THE FIRST PORTION OF THE
LONG TERM FORECAST PERIOD. THIS RIDGE WILL MOVE FROM THE NORTHERN
PLAINS ON MONDAY MORNING INTO THE OHIO VALLEY BY TUESDAY NIGHT.
EXPECT UPPER MICHIGAN WEATHER TO BE QUITE PLEASANT MONDAY AND
TUESDAY. ON MONDAY 850MB TEMPS WILL DIP TO AROUND 3-5C...AND WINDS
WILL BE NORTHERLY OFF LAKE SUPERIOR. KEPT HIGHS IN THE UPPER 50S AND
60S ACCORDINGLY. TUESDAY 850MB TEMPS WILL CLIMB TO THE 6-10C RANGE
AND SFC WINDS WILL SWING TO THE SOUTH...RAISING AFTERNOON HIGHS INTO
THE UPPER 60S AND LOW 70S...WHICH IS NORMAL FOR THIS TIME OF YEAR.
MEANWHILE...A DEEP 500MB LOW PRESSURE TROUGH MAKES ITS WAY ONSHORE
OVER THE NORTHWESTERN UNITED STATES. THE ASSOCIATED SFC LOW DEVELOPS
OVER MONTANA BY TUESDAY AFTERNOON...AND STRONG MOISTURE
TRANSPORT BRINGS PWATS UP TO 160 PERCENT OF NORMAL INTO WESTERN
UPPER MICHIGAN BY 06Z WEDNESDAY. AS THE LOW MOVES EASTWARD INTO THE
DAKOTAS THROUGH WEDNESDAY NIGHT...EXPECT THIS AREA OF STRONGER
MOISTURE ADVECTION TO MOVE EASTWARD THROUGH THE CWA. WITH A WEAK
SHORTWAVE FLATTENING THE EXITING RIDGE...AND AREA OF MOISTURE
ADVECTION FEEL THAT CHANCE TO SLIGHT CHANCE POPS ARE WARRANTED
ACROSS UPPER MICHIGAN FOR TUESDAY NIGHT AND WEDNESDAY-WITH HIGHER
POPS LOCATED FURTHER SOUTH NEAR THE BETTER FORCING. THE BEST
INSTABILITY ARRIVES LATER WEDNESDAY MORNING INTO THE AFTERNOON...SO
LEFT THUNDER OUT UNTIL THESE TIMES.
THURSDAY INTO SUNDAY WE DEAL WITH THE ARRIVAL OF THE ACTUAL
SFC/UPPER LEVEL LOW PRESSURE SYSTEM...WHICH MODELS CURRENTLY HAVE
TRAVERSING ACROSS THE UPPER GREAT LAKES. AS USUAL...MODEL
DIFFERENCES WILL GREATLY IMPACT THE FORECAST FOR THE WEEKEND...WITH
THE ECMWF/GEM BRINGING A CUT OFF 500MB LOW ACROSS NORTHEASTERN
MINNESOTA/NORTHERN ONTARIO BY FRIDAY AFTERNOON. THE GFS HAS A
NEUTRALLY TILTED TROUGH REACHING MINNESOTA AROUND THE SAME
TIME...WITH THE SURFACE LOW OVER ONTARIO JUST SOUTH OF JAMES BAY.
DESPITE DIFFERENCES...CAN AGREE THAT THIS WILL LIKELY BE A SOGGY END
TO THE WEEK...WITH MODELS PROJECTING PWATS 160-210 PERCENT OF
NORMAL. NOT GOING TO GET CUTE WITH THE GRIDS AT THIS POINT...BUT
WILL USE THE WPC DAY 3-7 FRONTS/PRESSURE LOCATIONS AS A GUIDE UNTIL
GREATER CONSISTENCY IS ACHIEVED. THIS PUTS THE SFC LOW DIRECTLY OVER
UPPER MICHIGAN ON FRIDAY MORNING...AND OVER QUEBEC BY SATURDAY
AFTERNOON.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 515 AM EDT SUN SEP 15 2013
ALTHOUGH SOME -SHRA WL IMPACT IWD AND THEN CMX EARLY THIS MRNG...
LINGERING LLVL DRY AIR WL MAINTAIN VFR CONDITIONS UNTIL LATER WHEN
THE PCPN MOISTENS THE LOWER LVLS SUFFICIENTLY AND LEADS TO MVFR
CIGS. THE PASSAGE OF A COLD FNT N-S THIS MRNG WL CAUSE A SHARP WSHFT
TO THE NNE AND BRING IFR CIGS AS SHALLOW COLD WEDGE FOLLOWS THIS
FROPA IN THE PRESENCE OF SOME -SHRA. EXPECT THE LOWEST IFR CIGS AT
SAW/IWD WHERE THE N WIND PRESENTS THE GREATEST UNSLOPE COMPONENT.
EXPECT A GRADUAL TRANSITION TO VFR WX IN THE AFTN WITH THE APRCH OF
HI PRES/ARRIVAL OF DRIER AIR. A STEADY N WIND WL DIMINISH BY THIS
EVNG WITH THE CLOSER APRCH OF THE HI/LOSS OF DAYTIME HEATING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 515 AM EDT SUN SEP 15 2013
NE WINDS UP TO 30 KNOTS TODAY ARE EXPECTED BEHIND A COLD FRONT
MOVING THROUGH LAKE SUPERIOR EARLY THIS MORNING. WINDS WILL DIMINISH
LATE THIS AFTERNOON AND TONIGHT AS HIGH PRESSURE BUILDS INTO THE
AREA. WITH THE HIGH DOMINATING THE REGION MON...WINDS WILL REMAIN
BELOW 20 KNOTS. AS THE HIGH SHIFTS TO THE EAST...SRLY WINDS UP TO
20 KNOTS ARE EXPECTED FROM TUE INTO WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FROST ADVISORY FROM 2 AM EDT /1 AM CDT/ TO 9 AM EDT /8 AM CDT/
MONDAY FOR MIZ002-004-005-009>011-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...MCD
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1243 PM CDT SUN SEP 15 2013
.UPDATE...
ISSUED AT 1015 AM CDT SUN SEP 15 2013
THE FORECAST WAS UPDATED THROUGH THIS EVENING TO REFLECT THE
LATEST CLOUD COVER AND WIND TRENDS. I INCREASED CLOUD COVER TODAY
TO HAVE THE CLOUDS CLEARING MUCH SLOWER THAN THE PREVIOUS
FORECAST. THE LATEST HRRR AND RAP13 RUNS INDICATE THE CLOUDS WILL
TAKE A WHILE TO CLEAR...WITH THE COOL NORTHERLY FLOW AND LOW
CONVECTIVE TEMPERATURES BOLSTERING THE CLOUD COVER UNTIL MID TO
LATE AFTERNOON.
I GAVE THE SOUTH SHORE OF WISCONSIN LOW CHANCES OF RAIN SHOWERS
DUE TO THE STRONG NE WINDS OFF LAKE SUPERIOR THROUGH EARLY THIS
AFTERNOON.
I WILL LOOK MORE INTO THE THREAT OF FROST AND FREEZING
TEMPERATURES TONIGHT THIS AFTERNOON.
UPDATE ISSUED AT 645 AM CDT SUN SEP 15 2013
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 315 AM CDT SUN SEP 15 2013
A COLD FRONT WILL PUSH ACROSS THE NORTHLAND THIS MORNING...EXITING
TO THE SOUTH BY THE AFTERNOON. LINGERING SPRINKLES/AREAS OF DRIZZLE
AND GUSTY NORTHEAST WINDS WILL ACCOMPANY THE FRONTAL PASSAGE THIS
MORNING. HIGH PRESSURE WILL BUILD INTO THE THE NORTHLAND FROM CANADA
THROUGH THE AFTERNOON...BRINGING GRADUALLY CLEARING SKIES AND
DIMINISHING WIND GUSTS. THE HIGH PRESSURE WILL SETTLE OVER THE
WESTERN LAKE SUPERIOR REGION TONIGHT...ALLOWING FOR CALM WINDS CLEAR
SKIES AND STRONG RADIATIONAL COOLING. LATEST MOS GUIDANCE CONTINUES
TO SHOW MOST LOCATIONS IN THE NORTHLAND SEE LOWS IN THE 30-35 DEGREE
RANGE TONIGHT. LOCALLY COOLER READINGS WILL BE FOUND ACROSS THE
IRON RANGE AS WELL AS IN THE HIGHER TERRAIN OF THE MINNESOTA
ARROWHEAD. WARMER READINGS OF 35-40 DEGREES WILL PREVAIL NEAR
LAKE SUPERIOR...AS WELL AS IN THE BRAINERD LAKES AREA. A FROST
ADVISORY FOR THE OVERNIGHT PERIOD WILL BE ISSUED WITH THE MORNING
FORECAST PACKAGE FOR ALL OF THE DLH ZONES EXCEPT CASS AND CROW
WING COUNTIES. THERE IS A POTENTIAL THAT THE FAR NORTHERN ZONES
WILL NEED TO BE UPGRADED TO A FREEZE WARNING IF DEW POINTS FALL
FAR ENOUGH WITH AFTERNOON MIXING TO ALLOW TEMPERATURES TO REACH
THE MID-UPPER 20S FOR A FEW HOURS OVERNIGHT.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 315 AM CDT SUN SEP 15 2013
QUIET WEATHER CONDITIONS TO START THE EXTENDED PERIOD AS HIGH
PRESSURE OVER THE GREAT LAKES AND AN UPPER RIDGE OVER THE MIDWEST
KEEP SKIES MOSTLY CLEAR AND THE WX DRY. LOW TEMPS TUE MORNING WILL
BE COOL...INTO THE MID 30S TO MID 40S...BUT QUICKLY WARM INTO THE
UPPER 60S AND LOWER 70S UNDER A WAA REGIME AND MOSTLY SUNNY SKIES
THROUGH TUESDAY. STRONG MIXING WILL ALLOW WINDS TO BECOME GUSTY IN
THE AFTERNOON...UP TO 20-25 MPH AT TIMES. AN UPPER TROUGH AND
ASSOCIATED SFC TROUGH/WARM FRONT WILL TRANSLATE E/NEWD ACROSS THE
NRN/CONTROL PLAINS TUE AFTERNOON AND MOVE INTO SRN AND CNTRL MN BY TUE
EVENING. THIS SYSTEM WILL INCREASE CLOUD COVER FROM SOUTH TO NORTH
DURING THE DAY...AND EVENTUALLY BRING IN CHANCES FOR RAIN SHOWERS
AND THUNDERSTORMS TUE NIGHT. THERE STILL EXIST SOME UNCERTAINTY WITH
THE TRACK OF THE SFC LOW AND THE TIMING OF A SECONDARY UPPER S/W
EXPECTED TO DRIVE EWD FROM MT THROUGH ND AND INTO NRN MN SOME TIME
BETWEEN WED AFTERNOON AND EARLY FRI MORNING. COULD SEE A WARM
SECTOR...POSSIBLY CAPPED...DEVELOP WED AFTERNOON PRIOR TO THE
PASSAGE OF AN EWD PROGRESSING COLD FRONT. SO...KEPT WITH LOWER CHC
POPS WED...AND AN INCREASE WED NIGHT THROUGH THUR EVENING. WHICH
WILL ALSO BE THE MOST FAVORABLE TIME FOR STRONG CONVECTION AND
THUNDERSTORMS.
AS THIS FAIRLY POTENT UPPER LOW TRACKS EWD ACROSS SRN MANITOBA AND
WRN ONTARIO...COLD CANADIAN AIR WILL BE DRAWN SWD INTO THE SYSTEM
AND FILTER INTO SECTIONS OF THE NORTHLAND. AFTER THE FAIRLY MILD
TEMPS WED AND THUR...CONDITIONS WILL BECOME RATHER COOL FRI AND SAT
WITH THIS SYSTEM...WITH HIGHS IN THE 50S AND 60S...AND OVERNIGHT
LOWS IN THE UPPER 30S AND LOWER 40S. WILL LIKELY SEE A FEW CAA
SHOWERS FRI AND SAT DURING THE AFTERNOON...WITH POSSIBLY SOME
CLEARING AND DRYING AT NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1236 PM CDT SUN SEP 15 2013
LARGE CANOPY OF LOW CLOUDS WILL GRDUALLY CLEAR FROM NORTH TO SOUTH
THIS AFTERNOON. IFR AT KDLH SHOULD LIFT TO MVFR BY MID AFTN.
EXPECT VFR OVERNIGHT EXCEPT FOR POTENTIAL BRIEF WINDOW OF BR AT ALL
SITES. CONFIDENCE IS NOT HIGH AT THIS POINT SO ONLY INCLUDED AT
KHIB/KBRD/KHYR.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 57 38 62 42 / 20 0 0 0
INL 59 30 66 39 / 0 0 0 0
BRD 63 36 65 45 / 10 0 0 0
HYR 60 30 64 38 / 20 0 0 0
ASX 57 34 63 39 / 40 0 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 8 AM CDT MONDAY FOR
MNZ010>012-018>021-026-035>038.
WI...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 8 AM CDT MONDAY FOR
WIZ001>004-006>009.
LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ121-
140>148.
&&
$$
UPDATE...GROCHOCINSKI
SHORT TERM...GRANING
LONG TERM...BJT
AVIATION...CANNON
AREA FORECAST DISCUSSION
NWS DULUTH MN
1015 AM CDT SUN SEP 15 2013
.UPDATE...
ISSUED AT 1015 AM CDT SUN SEP 15 2013
THE FORECAST WAS UPDATED THROUGH THIS EVENING TO REFLECT THE
LATEST CLOUD COVER AND WIND TRENDS. I INCREASED CLOUD COVER TODAY
TO HAVE THE CLOUDS CLEARING MUCH SLOWER THAN THE PREVIOUS
FORECAST. THE LATEST HRRR AND RAP13 RUNS INDICATE THE CLOUDS WILL
TAKE A WHILE TO CLEAR...WITH THE COOL NORTHERLY FLOW AND LOW
CONVECTIVE TEMPERATURES BOLSTERING THE CLOUD COVER UNTIL MID TO
LATE AFTERNOON.
I GAVE THE SOUTH SHORE OF WISCONSIN LOW CHANCES OF RAIN SHOWERS
DUE TO THE STRONG NE WINDS OFF LAKE SUPERIOR THROUGH EARLY THIS
AFTERNOON.
I WILL LOOK MORE INTO THE THREAT OF FROST AND FREEZING
TEMPERATURES TONIGHT THIS AFTERNOON.
UPDATE ISSUED AT 645 AM CDT SUN SEP 15 2013
UPDATED FOR AVIATION DISCUSSION.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 315 AM CDT SUN SEP 15 2013
A COLD FRONT WILL PUSH ACROSS THE NORTHLAND THIS MORNING...EXITING
TO THE SOUTH BY THE AFTERNOON. LINGERING SPRINKLES/AREAS OF DRIZZLE
AND GUSTY NORTHEAST WINDS WILL ACCOMPANY THE FRONTAL PASSAGE THIS
MORNING. HIGH PRESSURE WILL BUILD INTO THE THE NORTHLAND FROM CANADA
THROUGH THE AFTERNOON...BRINGING GRADUALLY CLEARING SKIES AND
DIMINISHING WIND GUSTS. THE HIGH PRESSURE WILL SETTLE OVER THE
WESTERN LAKE SUPERIOR REGION TONIGHT...ALLOWING FOR CALM WINDS CLEAR
SKIES AND STRONG RADIATIONAL COOLING. LATEST MOS GUIDANCE CONTINUES
TO SHOW MOST LOCATIONS IN THE NORTHLAND SEE LOWS IN THE 30-35 DEGREE
RANGE TONIGHT. LOCALLY COOLER READINGS WILL BE FOUND ACROSS THE
IRON RANGE AS WELL AS IN THE HIGHER TERRAIN OF THE MINNESOTA
ARROWHEAD. WARMER READINGS OF 35-40 DEGREES WILL PREVAIL NEAR
LAKE SUPERIOR...AS WELL AS IN THE BRAINERD LAKES AREA. A FROST
ADVISORY FOR THE OVERNIGHT PERIOD WILL BE ISSUED WITH THE MORNING
FORECAST PACKAGE FOR ALL OF THE DLH ZONES EXCEPT CASS AND CROW
WING COUNTIES. THERE IS A POTENTIAL THAT THE FAR NORTHERN ZONES
WILL NEED TO BE UPGRADED TO A FREEZE WARNING IF DEW POINTS FALL
FAR ENOUGH WITH AFTERNOON MIXING TO ALLOW TEMPERATURES TO REACH
THE MID-UPPER 20S FOR A FEW HOURS OVERNIGHT.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 315 AM CDT SUN SEP 15 2013
QUIET WEATHER CONDITIONS TO START THE EXTENDED PERIOD AS HIGH
PRESSURE OVER THE GREAT LAKES AND AN UPPER RIDGE OVER THE MIDWEST
KEEP SKIES MOSTLY CLEAR AND THE WX DRY. LOW TEMPS TUE MORNING WILL
BE COOL...INTO THE MID 30S TO MID 40S...BUT QUICKLY WARM INTO THE
UPPER 60S AND LOWER 70S UNDER A WAA REGIME AND MOSTLY SUNNY SKIES
THROUGH TUESDAY. STRONG MIXING WILL ALLOW WINDS TO BECOME GUSTY IN
THE AFTERNOON...UP TO 20-25 MPH AT TIMES. AN UPPER TROUGH AND
ASSOCIATED SFC TROUGH/WARM FRONT WILL TRANSLATE E/NEWD ACROSS THE
NRN/CONTROL PLAINS TUE AFTERNOON AND MOVE INTO SRN AND CNTRL MN BY TUE
EVENING. THIS SYSTEM WILL INCREASE CLOUD COVER FROM SOUTH TO NORTH
DURING THE DAY...AND EVENTUALLY BRING IN CHANCES FOR RAIN SHOWERS
AND THUNDERSTORMS TUE NIGHT. THERE STILL EXIST SOME UNCERTAINTY WITH
THE TRACK OF THE SFC LOW AND THE TIMING OF A SECONDARY UPPER S/W
EXPECTED TO DRIVE EWD FROM MT THROUGH ND AND INTO NRN MN SOME TIME
BETWEEN WED AFTERNOON AND EARLY FRI MORNING. COULD SEE A WARM
SECTOR...POSSIBLY CAPPED...DEVELOP WED AFTERNOON PRIOR TO THE
PASSAGE OF AN EWD PROGRESSING COLD FRONT. SO...KEPT WITH LOWER CHC
POPS WED...AND AN INCREASE WED NIGHT THROUGH THUR EVENING. WHICH
WILL ALSO BE THE MOST FAVORABLE TIME FOR STRONG CONVECTION AND
THUNDERSTORMS.
AS THIS FAIRLY POTENT UPPER LOW TRACKS EWD ACROSS SRN MANITOBA AND
WRN ONTARIO...COLD CANADIAN AIR WILL BE DRAWN SWD INTO THE SYSTEM
AND FILTER INTO SECTIONS OF THE NORTHLAND. AFTER THE FAIRLY MILD
TEMPS WED AND THUR...CONDITIONS WILL BECOME RATHER COOL FRI AND SAT
WITH THIS SYSTEM...WITH HIGHS IN THE 50S AND 60S...AND OVERNIGHT
LOWS IN THE UPPER 30S AND LOWER 40S. WILL LIKELY SEE A FEW CAA
SHOWERS FRI AND SAT DURING THE AFTERNOON...WITH POSSIBLY SOME
CLEARING AND DRYING AT NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 645 AM CDT SUN SEP 15 2013
IFR CIGS AT BRD HIB AND DLH WILL LIFT TO LOW-END MVFR BY 14/15Z.
MOST OF THE MVFR CIGS WILL PERSIST THROUGH THE EARLY AFTERNOON
FROM HIB SOUTHWARD...AND ERODE NORTH TO THE SOUTH FROM 20Z-23Z.
WINDS WILL INCREASE OUT OF THE NE THIS MORNING...WITH GUSTS UP TO
20 KT...BUT DIMINISH IN INTENSITY BY THE MID AFTERNOON. WINDS
BECOME LIGHT TONIGHT AND SKIES REMAIN CLEAR THROUGH THE EVENING.
COULD SEE PATCHY FOG DEVELOP...MAINLY AROUND HIB...BRD AND HYR
AFTER 07/08Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 57 38 62 42 / 20 0 0 0
INL 59 30 66 39 / 0 0 0 0
BRD 63 36 65 45 / 10 0 0 0
HYR 60 30 64 38 / 20 0 0 0
ASX 57 34 63 39 / 40 0 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 8 AM CDT MONDAY FOR
MNZ010>012-018>021-026-035>038.
WI...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 8 AM CDT MONDAY FOR
WIZ001>004-006>009.
LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ121-
140>148.
&&
$$
UPDATE...GROCHOCINSKI
SHORT TERM...GRANING
LONG TERM...BJT
AVIATION...GROCHOCINSKI
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1117 PM CDT Sat Sep 14 2013
.UPDATE:
Issued at 921 PM CDT Sat Sep 14 2013
Not any major changes to previous forecast for tonight. Have
updated hourly T grids to capture faster drop in temps than
previously forecast. However...did not drop mins as IR satellite
depicts increasing mid/high level cloudiness. Only other change of
note was to delay rain chances a few hours more in line with
latest HRRR guidance.
Gosselin
&&
.SHORT TERM: (Through Late Tonight)
Issued at 353 PM CDT Sat Sep 14 2013
Quiet weather continues in the short term as a sprawling high
pressure system over the Ohio Valley drifts east overnight. Light
and variable wind will become more southerly tonight as a result,
and increasing cloud cover from a trof of low pressure over the
Great Plains will keep temperatures from dipping to low tonight.
Guidance temperatures in the low to mid 50s look very reasonable.
The cold front approaching our area from the northwest is also
slower than expected, so have backed off pops for tonight as well.
Carney
.LONG TERM: (Sunday through Next Saturday)
Issued at 353 PM CDT Sat Sep 14 2013
Upper trough currently extending from the Hudson Bay southwestward
into northern Plains will move southeast into the southern Great
Lakes by tomorrow evening. Both the GFS and WRF based models show
that the attendant cold front will move south into the CWA reaching
close to a Pittsfield to Columbia line by 00Z, and south of the CWA
by 12Z Monday. Moisture convergence will increase along and just
ahead of the front with most of the large scale ascent coincident or
just behind the front. Will keep rain chances mainly north of I-70
during the day on Sunday and then spread them south during the
evening. Best chances will be on Sunday afternoon when best ascent
from upper trough will be lined up with best low level forcing and
instability.
Have kept slight or low chance of storms going Monday as front never
moves very far to the south. Low chances of storms still look
warranted Tuesday and Tuesday night as low level moisture convergence
will set up under shortwave trough passing through the area.
GFS/ECMWF/Canadian GEM each show that an upper trough will amplify
Wednesday into Friday as it moves from the Pacific Northwest into
Upper Midwest. The 00Z ECMWF does carve out a deeper upper low
than the more consistent GFS by late Friday. Moisture begins to
flow northward from the Gulf ahead of the trough by midweek, so will
leave in rain chances beginning Tuesday night and continue them into
Friday when a cold front moves through the area. 850mb temperatures
between 16-18C with clouds and rain chances support highs in the low
to mid 80`s ahead of the cold front.
Britt
&&
.AVIATION: (For the 06z TAFs through 06z Sunday Night)
Issued at 1052 PM CDT Sat Sep 14 2013
Just VFR mid-high level cloudiness late tgt ahead of an upper
level trough moving sewd through the nrn Plains. Sely sfc winds
will continue late tgt as the large sfc high centered over the
Ohio Valley region moves sewd. A cold front will drop sewd to the
UIN area Sunday aftn. There should be scattered showers and
thunderstorms along this front. Will include prob30 for shra/tsra in
the UIN taf Sunday aftn...and the rest of the taf sites Sunday evng.
Should also see VFR low-mid level cloudiness move into UIN as
well Sunday aftn...and the rest of the taf sites Sunday evng. The
ceiling may eventually drop into the MVFR catagory at UIN and COU
by late Sunday evng. The sfc wind will veer around to a s-swly
direction ahead of the front on Sunday at the taf sites. The wind
will shift to a n-nwly direction by late Sunday aftn in UIN after
fropa...and the rest of the taf sites Sunday evng.
Specifics for KSTL: Increasing high level clouds late tgt...then
mid level clouds moving in on Sunday...and VFR low-mid level
clouds Sunday evng as the cold front drops sewd into the STL area.
Will include prob30 for shra/tsra Sunday ngt in the STL taf. The
cloud ceiling may eventually drop into the MVFR catagory late
Sunday night. A sely sfc wind late tgt will increase to 10-11 kts
on Sunday and veer around to a swly direction. The sfc wind will
shift to a n-nwly direction Sunday evng after fropa.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GLASGOW MT
835 PM MDT MON SEP 16 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH WEDNESDAY...
EVENING UPDATE...SHOWERS AND THUNDERSTORMS HAVE MOVED INTO THE
WESTERN ZONES...AND ARE MOSTLY PRODUCING RAINFALL GUSTY WINDS AND
MAYBE SMALL HAIL. STORMS APPEAR TO BE RIDING ALONG THE SURFACE
TROUGH/WEAK BOUNDARY...AND SHOULD CONTINUE TO DIE OFF NOW THAT THE
SUN HAS SET AND INSTABILITY IS WEAKENING. ADJUSTED POP AND QPF GRIDS
TO REPRESENT THIS...AND INCLUDED ISOLATED RAIN SHOWERS INTO THE
CENTRAL PART OF THE CWA AFTER MIDNIGHT TO REFLECT CHANCES THAT THE
CURRENT CONVECTION MAY LINGER FOR A BIT LONGER TONIGHT. OTHERWISE
NO OTHER MAJOR CHANGES. BARNWELL
PREVIOUS UPDATE....BREEZY CONDITIONS CONTINUE ACROSS THE CWA THIS
EVENING BUT HAVE DROPPED BELOW LAKE WIND ADVISORY CRITERIA.
THEREFORE...HAVE CANCELED THE ADVISORY AT THIS TIME. ONLY OTHER
CONCERN WILL BE SHOWERS/STORMS APPROACHING PETROLEUM/PHILLIPS
COUNTY FROM THE WEST AND POTENTIAL FOR GUSTY WINDS. WILL NEED TO
MONITOR THROUGH THE EVENING BUT CONVECTION SHOULD FIZZLE AS IT
HEADS EASTWARD AND AFTER SUNSET. MAINTAINING ISOLATED POPS IN THE
GRIDS FOR MAINLY WESTERN HALF OF THE CWA FOR NOW. MALIAWCO
PREVIOUS SHORT TERM DISCUSSION...QUIET EVENING EXPECTED WITH
NORTHEAST MONTANA UNDER SOUTHWEST FLOW ALOFT. HRRR HAS BEEN
HINTING AT SOME SHOWER/THUNDERSTORM ACTIVITY ENTERING WESTERN
ZONES AND THIS HAS SUPPORT FROM THE LATEST NAM AND GFS
SOLUTIONS...ALTHOUGH ECMWF MAINTAINS DRY CONDITIONS. WILL INCLUDE
ISOLATED SHOWERS AND THUNDERSTORMS MAINLY FOR PETROLEUM AND
PHILLIPS COUNTIES. CANNOT RULE OUT POSSIBILITY INTO CENTRAL
PORTIONS OF THE CWA SO EXTENDED POPS A BIT FURTHER
EAST...HOWEVER...CONFIDENCE IS LOW. WILL EXPECT LITTLE MORE THAN
LEFTOVER CLOUD DEBRIS ACROSS MOST OF THE CWA OVERNIGHT IN THE FORM
OF HIGH CIRRUS. EXPECTING 850MB TEMPERATURES TO CONTINUE TO WARM
OVERNIGHT AND SO EXPECT MILDER LOWS TUESDAY MORNING AS COMPARED
WITH THIS MORNING. LASTLY...WILL KEEP AN EYE ON SURFACE WINDS WITH
THE LAKE WIND ADVISORY CONTINUING UNTIL 6PM. MOST MODEL GUIDANCE
INDICATES THAT WINDS WILL BEGIN TO RELAX WITHIN A FEW HOURS BUT
SPEEDS HAVE BEEN SUSTAINED AT OR ABOVE 20 MPH NOW FOR MUCH OF THE
DAY. AN UPDATE WILL BE SENT OUT IN A COUPLE OF HOURS WITH REGARD
TO THE GOING LAKE WIND ADVISORY.
TUESDAY THROUGH THURSDAY...UPPER TROUGH BEGINS TO TRANSLATE
EASTWARD ACROSS THE NORTHWEST AS ATTENTION TURNS TOWARD THE LOW
PRESSURE SYSTEM AS IT BEGINS TO AFFECT THE CWA. LATEST GFS AND
ECMWF ADVERTISE A DEEPENING SURFACE LOW WITH 997MB INTENSITY BY
WEDNESDAY AFTERNOON. NICE UPPER LEVEL DYNAMICS WILL COME INTO PLAY
WITH THE LOW PRESSURE SQUARELY WITHIN THE LEFT EXIT REGION OF THE
JET. THIS DEEPENING LOW WILL ALSO SERVE TO SHARPEN THE PRESSURE
GRADIENT ACROSS THE CWA AND SO INCREASED WINDS FOR THE PERIOD.
REGARDING PRECIPITATION CHANCES...CONCERNS SURROUND THE RAINFALL AMOUNT
WITH THIS SYSTEM AS THE TRACK OF THE SURFACE LOW IS STILL SOMEWHAT
UNCERTAIN. THE ECMWF AND GFS SHOW THE CENTER OF THE LOW TRACKING
ACROSS SOUTHEAST MONTANA AND THEN INTO NORTH DAKOTA AND EVENTUALLY
PUSHING INTO SOUTHERN MANITOBA. WOULD LIKE TO SEE THE TRACK A BIT
FURTHER SOUTH TO FEEL CONFIDENT IN WIDESPREAD WETTING RAINS AS
SUCH A TRACK LIKE WHAT IS PRESENTLY EXPECTED WOULD INTRODUCE
CONCERNS FOR A DRY SLOT SHUTTING OFF PRECIPITATION FOR A
TIME...ESPECIALLY ACROSS THE SOUTHERN AND SOUTHEASTERN ZONES NEAR
AND SOUTH OF THE TRACK. FURTHER NORTH NEAR THE INTERNATIONAL
BORDER...CONFIDENCE IS HIGHER ON STEADIER RAIN AND IN FACT
INTRODUCED THAT WORDING INTO THE GRIDS WITH SHOWERS FURTHER SOUTH
WHERE IT WILL BE MORE ISOLATED/SCATTERED IN NATURE.IN THE
STRATIFORM RAIN REGION DO EXPECT POTENTIAL EMBEDDED THUNDER AS
WELL DEPENDING ON MESOSCALE FORCING IN ADDITION TO LOCATION OF
BEST PVA AND UPPER LEVEL DYNAMICS. POSSIBILITY EXISTS IF THE CURRENT
FORECAST TRACK VERIFIES FOR SOME LOCATIONS TO PICK UP A RAINFALL
TOTAL EXCEEDING AN INCH BY THE END OF THE EVENT NEAR THE
INTERNATIONAL BORDER. WHILE STEADIEST RAINFALL WILL LIKELY BE
LOCATED NORTH OF THE MISSOURI RIVER...CANNOT RULE OUT THE
POSSIBILITY THAT FUTURE MODEL RUNS WILL SHIFT THE STORM TRACK
FURTHER SOUTH WHICH WOULD RESULT IN MORE WIDESPREAD WETTING RAINS.
LIKEWISE...SHOULD THE STORM TRACK FURTHER TO THE NORTH PER LATEST
NAM SOLUTION...MOST OF THE RAINFALL WOULD BE CONFINED TO SOUTHERN
SASKATCHEWAN AND MANITOBA...LEAVING THE CWA MAINLY DRY. NAM LOOKS
TO BE AN OUTLIER SOLUTION HOWEVER SO FOR NOW WILL DISREGARD THAT
SCENARIO. THE GOING FORECAST WILL LEAN TOWARD THE ECMWF/GFS/SREF
SOLUTIONS WITH GOOD CONSENSUS BEING SHOWN IN THE MODELS AND
CURRENT GRIDS NOW REFLECT LATEST THINKING. MALIAWCO
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
GOING FORECAST LOOKED GOOD BUT TO HELP WITH CONSISTENCY...ENDED
PRECIPITATION A BIT QUICKER THURSDAY. MODELS WERE HINTING AT
SLIGHTLY WARMER TEMPS ON THURSDAY AS WELL..SO RAISED THEM A COUPLE
DEGREES MOST PLACES.
LATE IN THE PERIOD...MODELS CONTINUE TO DISAGREE ABOUT SHOWERS
THAT FALL OUT FROM AN UPPER TROUGH. HAVE LEFT THIS PERIOD ALONE.
TFJ
PREVIOUS DISCUSSION...
THE EXTENDED BEGINS WITH AN ONGOING SYSTEM OVER THE NORTHERN
PLAINS AND CANADIAN PRAIRIES. THE MODELS ARE SIMILAR ON THE MAIN
FEATURES ON HOW THE SYSTEM DEVELOPS AND MOVES...HOWEVER
POSITIONING IS THE MAIN DIFFERENCE THROUGH THE PERIOD. WILL
CONTINUE TO SIDE WITH THE ECMWF FOR THE FORECAST TO FIT THE
FORECAST TREND.
THE EC/GEM ARE THE FASTEST ON GETTING THE PRECIP OUT OF THE AREA
ON THURSDAY WHERE THE GFS LINGERS...WILL RESPECT THE GFS ENOUGH
FOR LOW POPS THURSDAY.
FRIDAY THROUGH SATURDAY NIGHT HAS ANOTHER RIDGE AND FAIR WEATHER
FOR THE REGION.
SATURDAY NIGHT THROUGH MONDAY ANOTHER UPPER LEVEL SYSTEM MOVES
THROUGH THE REGION. THE MODELS HAVE THE SIMILAR IDEA THAT A SYSTEM
WILL MOVE THROUGH THE PLAINS OR PRAIRIES...HOWEVER LOCATION OF THE
SYSTEM IS DIFFERENT IN EACH MODEL TO PROVIDE INCREASE CONFIDENCE
AT THIS TIME TO INCREASE PRECIPITATION CHANCES. PROTON
&&
.AVIATION...
FLIGHT CATEGORY: VFR.
THUNDER: A CLUSTER OF THUNDERSTORMS IN PHILLIPS COUNTY DURING THE
EARLY EVENING WILL CONTINUE MOVING NORTHEAST...THESE SHOWERS WILL
MOST LIKELY FALL APART BY THE LATE EVENING. HOWEVER AN ISOLATED
CHANCE FOR THEM TO IMPACT KGGW DOES EXIST. MAIN IMPACT WOULD MOST
LIKELY BE A STRONG GUSTY WINDS FROM THE WEST VIA ANY OUTFLOW
BOUNDARIES FROM DYING STORMS. AMENDMENTS ARE NOT LIKELY BUT COULD
OCCUR.
AREA WINDS: WILL BE LIGHT OUT OF THE SOUTHWEST TONIGHT... SWITCHING
TO THE WEST TOMORROW... BEFORE DIMINISHING TO LIGHT AND VARIABLE
OVERNIGHT. GAH
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
545 PM MDT MON SEP 16 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH WEDNESDAY...
545PM UPDATE...
BREEZY CONDITIONS CONTINUE ACROSS THE CWA THIS EVENING BUT HAVE
DROPPED BELOW LAKE WIND ADVISORY CRITERIA. THEREFORE...HAVE
CANCELED THE ADVISORY AT THIS TIME. ONLY OTHER CONCERN WILL BE
SHOWERS/STORMS APPROACHING PETROLEUM/PHILLIPS COUNTY FROM THE WEST
AND POTENTIAL FOR GUSTY WINDS. WILL NEED TO MONITOR THROUGH THE
EVENING BUT CONVECTION SHOULD FIZZLE AS IT HEADS EASTWARD AND
AFTER SUNSET. MAINTAINING ISOLATED POPS IN THE GRIDS FOR MAINLY
WESTERN HALF OF THE CWA FOR NOW. MALIAWCO
PREVIOUS SHORT TERM DISCUSSION...
QUIET EVENING EXPECTED WITH NORTHEAST MONTANA UNDER SOUTHWEST FLOW
ALOFT. HRRR HAS BEEN HINTING AT SOME SHOWER/THUNDERSTORM ACTIVITY
ENTERING WESTERN ZONES AND THIS HAS SUPPORT FROM THE LATEST NAM
AND GFS SOLUTIONS...ALTHOUGH ECMWF MAINTAINS DRY CONDITIONS. WILL
INCLUDE ISOLATED SHOWERS AND THUNDERSTORMS MAINLY FOR PETROLEUM
AND PHILLIPS COUNTIES. CANNOT RULE OUT POSSIBILITY INTO CENTRAL
PORTIONS OF THE CWA SO EXTENDED POPS A BIT FURTHER
EAST...HOWEVER...CONFIDENCE IS LOW. WILL EXPECT LITTLE MORE THAN
LEFTOVER CLOUD DEBRIS ACROSS MOST OF THE CWA OVERNIGHT IN THE FORM
OF HIGH CIRRUS. EXPECTING 850MB TEMPERATURES TO CONTINUE TO WARM
OVERNIGHT AND SO EXPECT MILDER LOWS TUESDAY MORNING AS COMPARED
WITH THIS MORNING. LASTLY...WILL KEEP AN EYE ON SURFACE WINDS WITH
THE LAKE WIND ADVISORY CONTINUING UNTIL 6PM. MOST MODEL GUIDANCE
INDICATES THAT WINDS WILL BEGIN TO RELAX WITHIN A FEW HOURS BUT
SPEEDS HAVE BEEN SUSTAINED AT OR ABOVE 20 MPH NOW FOR MUCH OF THE
DAY. AN UPDATE WILL BE SENT OUT IN A COUPLE OF HOURS WITH REGARD
TO THE GOING LAKE WIND ADVISORY.
TUESDAY THROUGH THURSDAY...UPPER TROUGH BEGINS TO TRANSLATE
EASTWARD ACROSS THE NORTHWEST AS ATTENTION TURNS TOWARD THE LOW
PRESSURE SYSTEM AS IT BEGINS TO AFFECT THE CWA. LATEST GFS AND
ECMWF ADVERTISE A DEEPENING SURFACE LOW WITH 997MB INTENSITY BY
WEDNESDAY AFTERNOON. NICE UPPER LEVEL DYNAMICS WILL COME INTO PLAY
WITH THE LOW PRESSURE SQUARELY WITHIN THE LEFT EXIT REGION OF THE
JET. THIS DEEPENING LOW WILL ALSO SERVE TO SHARPEN THE PRESSURE
GRADIENT ACROSS THE CWA AND SO INCREASED WINDS FOR THE PERIOD.
REGARDING PRECIPITATION CHANCES...CONCERNS SURROUND THE RAINFALL AMOUNT
WITH THIS SYSTEM AS THE TRACK OF THE SURFACE LOW IS STILL SOMEWHAT
UNCERTAIN. THE ECMWF AND GFS SHOW THE CENTER OF THE LOW TRACKING
ACROSS SOUTHEAST MONTANA AND THEN INTO NORTH DAKOTA AND EVENTUALLY
PUSHING INTO SOUTHERN MANITOBA. WOULD LIKE TO SEE THE TRACK A BIT
FURTHER SOUTH TO FEEL CONFIDENT IN WIDESPREAD WETTING RAINS AS
SUCH A TRACK LIKE WHAT IS PRESENTLY EXPECTED WOULD INTRODUCE
CONCERNS FOR A DRY SLOT SHUTTING OFF PRECIPITATION FOR A
TIME...ESPECIALLY ACROSS THE SOUTHERN AND SOUTHEASTERN ZONES NEAR
AND SOUTH OF THE TRACK. FURTHER NORTH NEAR THE INTERNATIONAL
BORDER...CONFIDENCE IS HIGHER ON STEADIER RAIN AND IN FACT
INTRODUCED THAT WORDING INTO THE GRIDS WITH SHOWERS FURTHER SOUTH
WHERE IT WILL BE MORE ISOLATED/SCATTERED IN NATURE.IN THE
STRATIFORM RAIN REGION DO EXPECT POTENTIAL EMBEDDED THUNDER AS
WELL DEPENDING ON MESOSCALE FORCING IN ADDITION TO LOCATION OF
BEST PVA AND UPPER LEVEL DYNAMICS. POSSIBILITY EXISTS IF THE CURRENT
FORECAST TRACK VERIFIES FOR SOME LOCATIONS TO PICK UP A RAINFALL
TOTAL EXCEEDING AN INCH BY THE END OF THE EVENT NEAR THE
INTERNATIONAL BORDER. WHILE STEADIEST RAINFALL WILL LIKELY BE
LOCATED NORTH OF THE MISSOURI RIVER...CANNOT RULE OUT THE
POSSIBILITY THAT FUTURE MODEL RUNS WILL SHIFT THE STORM TRACK
FURTHER SOUTH WHICH WOULD RESULT IN MORE WIDESPREAD WETTING RAINS.
LIKEWISE...SHOULD THE STORM TRACK FURTHER TO THE NORTH PER LATEST
NAM SOLUTION...MOST OF THE RAINFALL WOULD BE CONFINED TO SOUTHERN
SASKATCHEWAN AND MANITOBA...LEAVING THE CWA MAINLY DRY. NAM LOOKS
TO BE AN OUTLIER SOLUTION HOWEVER SO FOR NOW WILL DISREGARD THAT
SCENARIO. THE GOING FORECAST WILL LEAN TOWARD THE ECMWF/GFS/SREF
SOLUTIONS WITH GOOD CONSENSUS BEING SHOWN IN THE MODELS AND
CURRENT GRIDS NOW REFLECT LATEST THINKING. MALIAWCO
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
GOING FORECAST LOOKED GOOD BUT TO HELP WITH CONSISTENCY...ENDED
PRECIPITATION A BIT QUICKER THURSDAY. MODELS WERE HINTING AT
SLIGHTLY WARMER TEMPS ON THURSDAY AS WELL..SO RAISED THEM A COUPLE
DEGREES MOST PLACES.
LATE IN THE PERIOD...MODELS CONTINUE TO DISAGREE ABOUT SHOWERS
THAT FALL OUT FROM AN UPPER TROUGH. HAVE LEFT THIS PERIOD ALONE.
TFJ
PREVIOUS DISCUSSION...
THE EXTENDED BEGINS WITH AN ONGOING SYSTEM OVER THE NORTHERN
PLAINS AND CANADIAN PRAIRIES. THE MODELS ARE SIMILAR ON THE MAIN
FEATURES ON HOW THE SYSTEM DEVELOPS AND MOVES...HOWEVER
POSITIONING IS THE MAIN DIFFERENCE THROUGH THE PERIOD. WILL
CONTINUE TO SIDE WITH THE ECMWF FOR THE FORECAST TO FIT THE
FORECAST TREND.
THE EC/GEM ARE THE FASTEST ON GETTING THE PRECIP OUT OF THE AREA
ON THURSDAY WHERE THE GFS LINGERS...WILL RESPECT THE GFS ENOUGH
FOR LOW POPS THURSDAY.
FRIDAY THROUGH SATURDAY NIGHT HAS ANOTHER RIDGE AND FAIR WEATHER
FOR THE REGION.
SATURDAY NIGHT THROUGH MONDAY ANOTHER UPPER LEVEL SYSTEM MOVES
THROUGH THE REGION. THE MODELS HAVE THE SIMILAR IDEA THAT A SYSTEM
WILL MOVE THROUGH THE PLAINS OR PRAIRIES...HOWEVER LOCATION OF THE
SYSTEM IS DIFFERENT IN EACH MODEL TO PROVIDE INCREASE CONFIDENCE
AT THIS TIME TO INCREASE PRECIPITATION CHANCES. PROTON
&&
.AVIATION...
FLIGHT CATEGORY: VFR.
A CLUSTER OF THUNDERSTORMS NEAR BOZEMAN DURING THE MID AFTERNOON
WILL CONTINUE MOVING NORTHEAST...POSSIBLY REACHING THE GLASGOW
AREA LATER THIS EVENING BEFORE THEY FALL APART. SHOWERS/THUNDERSTORMS
ARE NOT EXPECTED EAST OF A GLASGOW TO JORDAN LINE. CLEARING SKIES
WILL OCCUR IN THE WAKE OF TONIGHT/S WEATHER BUT ANOTHER ROUND OF
SHOWERS/ISOLATED STORMS WILL MOVE IN LATE TUESDAY.
SOUTHEAST WINDS WILL DIMINISH BY EARLY EVENING WITH LIGHT AND
VARIABLE WINDS LATE TONIGHT AND TUESDAY. TFJ
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
717 AM CDT SUN SEP 15 2013
.UPDATE...
ISSUED AT 717 AM CDT SUN SEP 15 2013
RAIN...SHOWERS AND ISOLATED THUNDERSTORMS ARE EXITING A BIT SLOWER
THAN FORECAST. A NEW FORECAST IS OUT WHICH DELAYS THE RAIN EXITING
BY 3 HOURS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 315 AM CDT SUN SEP 15 2013
TODAY AND TONIGHT...THE ONGOING DISTURBANCE AND ASSOCIATED SHOWERS
AND THUNDERSTORMS ACROSS SOUTHWEST AND SOUTH CENTRAL NEBRASKA IS
EXPECTED TO EXIT THE FORECAST AREA BY MID MORNING.
A STRONG CANADIAN COLD FRONT WILL SWEEP THE FORECAST AREA THIS
MORNING. THIS HIGH PRESSURE SYSTEM IS EXPECTED TO TRACK INTO THE
UPPER MIDWEST TONIGHT. THIS WILL PRODUCE UPSLOPE EAST WINDS ACROSS
THE FORECAST AREA WHICH COULD PRODUCE LOW CLOUDINESS TONIGHT. ITS
NOT CLEAR THIS WILL HAPPEN SINCE THE MODEL FORECAST SOUNDINGS SHOW
LOW LEVEL MOISTURE INCREASING BUT THIS DOES NOT ALWAYS PRODUCE LOW
CLOUDINESS.
STRATUS IS EXPECTED ACROSS MUCH OF THE FORECAST AREA THIS MORNING
AND THIS SHOULD KEEP HIGH TEMPERATURES IN THE 60S TO AROUND 70 FOR
HIGHS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 315 AM CDT SUN SEP 15 2013
FOR MONDAY...RETURN FLOW SETS UP ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA DURING THE DAY AS SURFACE HIGH PRESSURE BUILDS EAST
ACROSS THE GREAT LAKES. MOISTURE AND LIFT IS SHOWN TO INCREASE
INTO THE AFTERNOON HOURS AS A WEAK WAVE LIFTS ACROSS THE NORTHERN
AND CENTRAL PLAINS. BEST CHANCES OF PRECIPITATION APPEAR TO BE
FOCUSED DURING THE EVENING AND POSSIBLY OVERNIGHT HOURS ACROSS
SOUTHERN AND EASTERN PORTIONS OF THE FORECAST AREA...GENERALLY
TIED TO THE BEST MOISTURE TRANSPORT AND STRENGTHENING LOW LEVEL
JET. HIGHS ON MONDAY WILL ONCE AGAIN BE BELOW AVERAGE...PARTIALLY
DUE TO PERSISTENT OVERCAST CONDITIONS. THE REGION WILL SEE A QUICK
WARM UP FOR TUESDAY AND WEDNESDAY AS A UPPER TROUGH DEEPENS ACROSS
THE PACIFIC NORTHWEST. HIGHS WILL RISE WELL INTO THE 80S FOR MOST
LOCATIONS BOTH DAYS...WITH THE HIGHEST READINGS GENERALLY FOUND
ACROSS THE EASTERN PANHANDLE AND SOUTHWEST NEBRASKA. THERE MAY BE
A FEW STORMS LINGERING ACROSS THE EAST EARLY TUESDAY...AND THEN
POSSIBLY FORMING LATE WEDNESDAY ACROSS THE WEST AS THE UPPER
TROUGH APPROACHES...BUT MOST LOCATIONS SHOULD REMAIN PRECIP FREE
MIDWEEK. A STRONG COLD FRONT ASSOCIATED WITH THE PAC NW TROUGH
WILL CRUISE THROUGH THE FORECAST AREA LATE ON WEDNESDAY...BRINGING
A CHANCE OF STORMS BACK TO THE AREA. PREVIOUS FORECAST INTRODUCED
A SLIGHT CHANCE MENTION FOR MOST PLACES...WILL GENERALLY MAINTAIN
AS THERE REMAINS SOME DISAGREEMENT BETWEEN THE LONGER RANGE
SOLUTIONS....THIS IS DESPITE THE ALL BLEND INDICATING SOME CHANCE
WORDING. THE 00Z GFS IS STRONGER WITH THE TROUGH AND FOCUSES MOST
OF THE QPF ACROSS NORTH CENTRAL NEBRASKA...THE 00Z EURO IS MUCH
MORE PROGRESSIVE WITH THE FROPA AND GENERATES LESS QPF COVERAGE.
OTHERWISE BEHIND POST FRONTAL CONDITIONS SEASONAL TEMPERATURES
WILL BE EXPECTED WITH GENERALLY DRY CONDITIONS FOR THE END OF THE
WORK WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 632 AM CDT SUN SEP 15 2013
IFR/MVFR CIGS AND AREAS OF RAIN/ISOLATED TSTMS WILL IMPROVE TO
MVFR/VFR LATE THIS MORNING AND VFR FOR A FEW HOURS THIS AFTN. HIGH
PRESSURE ACROSS SASKATCHAWAN WILL BUILD INTO THE UPPER MIDWEST
TONIGHT WITH EASTERLY UPSLOPE WINDS DEVELOPING ACROSS WRN/NCNTL
NEB. THE RAP MODEL AND OTHER SUGGEST STATUS WILL REDEVELOP WITH
MVFR CIGS FORMING...PERHAPS IFR ALONG AND/OR WEST OF HIGHWAY 83.
LASTLY...VFR AT KLBF COULD BECOME MVFR AT ANY TIME AS WEAK HIGH
PRESSURE FROM THE HEAVY RAIN ERODES.
&&
.HYDROLOGY...
ISSUED AT 717 AM CDT SUN SEP 15 2013
A COORDINATION CALL WITH THE MB RIVER FORECAST CENTER INDICATES
THE GAGE READINGS AT WELDONA AND BALZAC MAY NOT BE FAULTY. WFO BOU
IS ATTEMPTING TO CONTACT LOCAL OFFICICAL TO GET VISUAL
CONFIRMATION AT THESE LOCATIONS. UNTIL THIS PROCESS IS COMPLETE
THE GAGE READINGS WILL USED AT FACE VALUE AND RECORD FLOODING WILL
BE FORECAST AT BALZAC.
THERE IS NO CHANGE TO THE FORECAST AT ROSCOE PENDING VERIFICATION
OF THE BALZAC AND WELDONA GAGE READINGS.
OTHERWISE...HEAVY RAIN HAS FALLEN OVERNIGHT IN THE SOUTH PLATTE
BASIN BELOW WELDONA WITH LOCAL RAINFALL AMOUNTS OF 2.31 INCHES AT
SIDNEY AND 2.82 INCHES AT NORTH PLATTE. THIS COMPLICATES THE FORECAST
PROCESS OF THE IMPENDING FLOOD WAVE. THE FLOOD WAVE IS APPROACHING
THE BALZAC GAGE BELOW WELDONA THIS MORNING AND THE RIVER SHOULD
CREST THIS MORNING. THE FORECAST FOR RIVER POINTS BELOW
BALZAC...INCLUDING NEBRASKA ARE UNCERTAIN.
THE LATEST FORECAST FOR ROSCOE ISSUED SATURDAY EVENING SHOWS THE
SOUTH PLATTE RISING TUESDAY AND CRESTING AROUND 9 FEET THURSDAY.
FLOOD STAGE IS 9.0 FEET. A FLOOD WATCH IS IN EFFECT FOR THE SOUTH
PLATTE RIVER AT ROSCOE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CDC
SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...CDC
HYDROLOGY...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
632 AM CDT SUN SEP 15 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 315 AM CDT SUN SEP 15 2013
TODAY AND TONIGHT...THE ONGOING DISTURBANCE AND ASSOCIATED SHOWERS
AND THUNDERSTORMS ACROSS SOUTHWEST AND SOUTH CENTRAL NEBRASKA IS
EXPECTED TO EXIT THE FORECAST AREA BY MID MORNING.
A STRONG CANADIAN COLD FRONT WILL SWEEP THE FORECAST AREA THIS
MORNING. THIS HIGH PRESSURE SYSTEM IS EXPECTED TO TRACK INTO THE
UPPER MIDWEST TONIGHT. THIS WILL PRODUCE UPSLOPE EAST WINDS ACROSS
THE FORECAST AREA WHICH COULD PRODUCE LOW CLOUDINESS TONIGHT. ITS
NOT CLEAR THIS WILL HAPPEN SINCE THE MODEL FORECAST SOUNDINGS SHOW
LOW LEVEL MOISTURE INCREASING BUT THIS DOES NOT ALWAYS PRODUCE LOW
CLOUDINESS.
STRATUS IS EXPECTED ACROSS MUCH OF THE FORECAST AREA THIS MORNING
AND THIS SHOULD KEEP HIGH TEMPERATURES IN THE 60S TO AROUND 70 FOR
HIGHS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 315 AM CDT SUN SEP 15 2013
FOR MONDAY...RETURN FLOW SETS UP ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA DURING THE DAY AS SURFACE HIGH PRESSURE BUILDS EAST
ACROSS THE GREAT LAKES. MOISTURE AND LIFT IS SHOWN TO INCREASE
INTO THE AFTERNOON HOURS AS A WEAK WAVE LIFTS ACROSS THE NORTHERN
AND CENTRAL PLAINS. BEST CHANCES OF PRECIPITATION APPEAR TO BE
FOCUSED DURING THE EVENING AND POSSIBLY OVERNIGHT HOURS ACROSS
SOUTHERN AND EASTERN PORTIONS OF THE FORECAST AREA...GENERALLY
TIED TO THE BEST MOISTURE TRANSPORT AND STRENGTHENING LOW LEVEL
JET. HIGHS ON MONDAY WILL ONCE AGAIN BE BELOW AVERAGE...PARTIALLY
DUE TO PERSISTENT OVERCAST CONDITIONS. THE REGION WILL SEE A QUICK
WARM UP FOR TUESDAY AND WEDNESDAY AS A UPPER TROUGH DEEPENS ACROSS
THE PACIFIC NORTHWEST. HIGHS WILL RISE WELL INTO THE 80S FOR MOST
LOCATIONS BOTH DAYS...WITH THE HIGHEST READINGS GENERALLY FOUND
ACROSS THE EASTERN PANHANDLE AND SOUTHWEST NEBRASKA. THERE MAY BE
A FEW STORMS LINGERING ACROSS THE EAST EARLY TUESDAY...AND THEN
POSSIBLY FORMING LATE WEDNESDAY ACROSS THE WEST AS THE UPPER
TROUGH APPROACHES...BUT MOST LOCATIONS SHOULD REMAIN PRECIP FREE
MIDWEEK. A STRONG COLD FRONT ASSOCIATED WITH THE PAC NW TROUGH
WILL CRUISE THROUGH THE FORECAST AREA LATE ON WEDNESDAY...BRINGING
A CHANCE OF STORMS BACK TO THE AREA. PREVIOUS FORECAST INTRODUCED
A SLIGHT CHANCE MENTION FOR MOST PLACES...WILL GENERALLY MAINTAIN
AS THERE REMAINS SOME DISAGREEMENT BETWEEN THE LONGER RANGE
SOLUTIONS....THIS IS DESPITE THE ALL BLEND INDICATING SOME CHANCE
WORDING. THE 00Z GFS IS STRONGER WITH THE TROUGH AND FOCUSES MOST
OF THE QPF ACROSS NORTH CENTRAL NEBRASKA...THE 00Z EURO IS MUCH
MORE PROGRESSIVE WITH THE FROPA AND GENERATES LESS QPF COVERAGE.
OTHERWISE BEHIND POST FRONTAL CONDITIONS SEASONAL TEMPERATURES
WILL BE EXPECTED WITH GENERALLY DRY CONDITIONS FOR THE END OF THE
WORK WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 632 AM CDT SUN SEP 15 2013
IFR/MVFR CIGS AND AREAS OF RAIN/ISOLATED TSTMS WILL IMPROVE TO
MVFR/VFR LATE THIS MORNING AND VFR FOR A FEW HOURS THIS AFTN. HIGH
PRESSURE ACROSS SASKATCHAWAN WILL BUILD INTO THE UPPER MIDWEST
TONIGHT WITH EASTERLY UPSLOPE WINDS DEVELOPING ACROSS WRN/NCNTL
NEB. THE RAP MODEL AND OTHER SUGGEST STATUS WILL REDEVELOP WITH
MVFR CIGS FORMING...PERHAPS IFR ALONG AND/OR WEST OF HIGHWAY 83.
LASTLY...VFR AT KLBF COULD BECOME MVFR AT ANY TIME AS WEAK HIGH
PRESSURE FROM THE HEAVY RAIN ERODES.
&&
.HYDROLOGY...
ISSUED AT 632 AM CDT SUN SEP 15 2013
RECORD FLOODING ON THE SOUTH PLATTE RIVER IN GREELEY
COLORADO HAS DISABLED THE DOWNSTREAM RIVER GAGE AT WELDONA AND BALZAC.
MEANWHILE...HEAVY RAIN HAS FALLEN OVERNIGHT IN THE SOUTH PLATTE
BASIN BELOW WELDONA. BOTH OF THESE DEVELOPMENTS COMPLICATES THE
FORECAST PROCESS OF THE IMPENDING FLOOD WAVE. THE FLOOD WAVE IS
APPROACHING THE BALZAC GAGE BELOW WELDONA THIS MORNING AND THE RIVER
SHOULD CREST MONDAY MORNING. AT 530 AM CDT IT APPEARED THE GAGE
WAS FAILING LIKE THE WELDONA GAGE. THE FORECAST FOR RIVER POINTS
BELOW BALZAC...INCLUDING NEBRASKA ARE UNCERTAIN.
THE LATEST FORECAST FOR ROSCOE ISSUED SATURDAY EVENING SHOWS THE
SOUTH PLATTE RISING TUESDAY AND CRESTING AROUND 9 FEET THURSDAY.
FLOOD STAGE IS 9.0 FEET. A FLOOD WATCH IS IN EFFECT FOR THE SOUTH
PLATTE RIVER AT ROSCOE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...CDC
HYDROLOGY...CDC
AREA FORECAST DISCUSSION
NWS BUFFALO NY
815 PM EDT MON SEP 16 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVERHEAD TONIGHT AND TUESDAY...BRINGING
CLEARING SKIES AND CHILLY TEMPERATURES TONIGHT...THEN A MILDER DAY
ON TUESDAY. THE HIGH WILL THEN DRIFT OFF THE EAST COAST WEDNESDAY
AND THURSDAY...WHICH WILL ALLOW A SOUTHWESTERLY FLOW OF WARMER AIR
TO OVERSPREAD THE REGION. OTHERWISE...EXPECT LARGELY DRY WEATHER
UNTIL THE NEXT COLD FRONT APPROACHES FRIDAY AND FRIDAY NIGHT.
&&
.NEAR TERM /THROUGH TUESDAY/...
A BROAD AREA OF SURFACE HIGH PRESSURE IS CENTERED OVER THE MICHIGAN
UPPER PENINSULA THIS EVENING. THE INFLUENCE OF DRY AIR AND
SUBSIDENCE FROM THIS HIGH EXTENDS ACROSS NEW YORK INTO NEW ENGLAND.
THE LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS ARE SHOWING
CLEAR SKIES ACROSS MUCH OF NEW YORK WITH LINGERING OVERCAST SKIES
CONFINED TO THE NY SOUTHERN TIER. THIS AREA OF CLOUD COVER HAS BEEN
ERODING FROM THE NORTH RECENTLY AS THE DRIER AIR SPREADS SOUTH AND
EXPECT CLEAR SKIES HERE BY MIDNIGHT. HAVE ADDED A LOW CHANE OF RAIN
ACROSS THE INTERIOR SOUTHERN TIER WHERE OLEAN IS REPORTING RAIN
AS NORTHERLY FLOW UPSLOPE OVER THE HIGHER TERRAIN.
CLEAR SKIES WILL REMAIN FOR THE BALANCE OF TONIGHT AND TUESDAY AS
THE SURFACE HIGH SETTLES DIRECTLY OVERHEAD. SOME LAKE EFFECT CLOUD
COVER COULD DEVELOP LATER ON...LATEST HRRR RUNS SHOW SOME LIMITED
LAKE CLOUDS FORMING FROM THE NIAGARA FRONTIER OVER TO ROCHESTER
OVERNIGHT MAINLY AFTER MIDNIGHT IN THE NORTHEAST FLOW OVER LAKE
ONTARIO. COVERAGE WILL BE LIMITED GIVEN THE VERY DRY NATURE OF THE
INCOMING AIRMASS.
WITH RESPECT TO TEMPERATURES...EXCELLENT CONDITIONS FOR RADIATIONAL
COOLING ARE DEVELOPING TONIGHT WITH CLEARING SKIES AND WINDS
BECOMING LIGHT. THIS WILL RESULT IN LOW TEMPERATURES DROPPING INTO THE
UPPER 30S TO LOWER 40S ALONG THE LAKE PLAINS...WITH PROGRESSIVELY
COLDER READINGS IN THE MID TO LOWER 30S WITH FURTHER INLAND EXTENT.
THIS SHOULD RESULT IN A HIGH LIKELIHOOD OF FROST ACROSS INTERIOR
PORTIONS OF THE SOUTHERN TIER AND AN ALMOST CERTAIN FROST/FREEZE
ACROSS INTERIOR PORTIONS OF THE NORTH COUNTRY...WITH PATCHIER BUT
STILL NOTEWORTHY FROST EXTENDING INTO ADJOINING PORTIONS OF SOUTHERN
ERIE AND WYOMING COUNTIES...AND INTERIOR PORTIONS OF THE FINGER
LAKES. FOR THIS REASON...FROST/FREEZE HEADLINES REMAIN IN EFFECT AS
OUTLINED BELOW.
AFTER A CHILLY START...PLENTIFUL SUNSHINE COUPLED WITH 850 MB TEMPS
REBOUNDING TO THE +4C TO +7C RANGE SHOULD THEN ALLOW FOR A NICE
RECOVERY IN TEMPERATURES ON TUESDAY...WITH MOST LOCATIONS SEEING
READINGS WARM INTO THE MID 60S DURING THE AFTERNOON.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
HIGH PRESSURE ACROSS THE REGION ON TUESDAY NIGHT WILL GRADUALLY
DRIFT OFF THE NEW JERSEY COAST THROUGH THURSDAY. THIS WILL BRING A COUPLE
OF DAYS OF FAIR WEATHER TO THE REGION. A WEAK WARM FRONTAL BOUNDARY
IS FORECAST TO LIFT TOWARD THE REGION FROM THE OHIO VALLEY ON
THURSDAY. THIS MAY GENERATE SCATTERED SHOWERS IN FAR WESTERN
PORTIONS OF THE CWA BUT ANY SHOWERS SHOULD APART AS THEY TRACK INTO
DRIER AIR TO THE EAST CLOSER TO THE SURFACE HIGH.
TEMPERATURES WILL START OFF CHILLY ON TUESDAY NIGHT...WITH ISOLATED
FROST POSSIBLE ACROSS THE COOLEST VALLEY LOCATIONS IN THE SOUTHERN
TIER AND IN LEWIS COUNTIES. TEMPERATURES WILL REBOUND NICELY ON
WEDNESDAY...AS THE SOUTHERLY RETURN FLOW HELPS WARM TEMPERATURES
BACK INTO THE LOWER 70S ON THURSDAY. WARMER AIR ALOFT WILL MORE THAN
OFFSET THE INCREASING CLOUDS ON THURSDAY...WITH HIGHS A FEW DEGREES
WARMER.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE PRIMARY FEATURE OF CONCERN IS A SIGNIFICANT UPPER LEVEL TROF
WHICH WILL EXTEND FROM NW ONTARIO PROVINCE TO HUDSON BAY ON THURSDAY
NIGHT. THERE IS BROAD MODEL CONSENSUS (GGEM/GFS/EUROPEAN) THAT THIS
TROF WILL CLOSE OFF AS IT SLOWLY TRACKS TO THE EAST. THIS WILL PUSH
LOW PRESSURE AND AN ASSOCIATED FRONTAL BOUNDARY VERY SLOWLY TOWARD
OUR REGION. ALTHOUGH THERE IS HIGH CONFIDENCE THAT THERE WILL BE A
FRONTAL PASSAGE...THE TIMING OF THIS IS UNCERTAIN. THE
12Z GGEM AND ECMWF ARE CONSIDERABLY SLOWER THAN THE 12Z GFS AND 00Z
ECMWF. USING A CONSENSUS OF AVAILABLE GUIDANCE...THE FRONT WILL MOST
LIKELY PASS LATE FRIDAY NIGHT INTO SATURDAY. SHOWERS AND
THUNDERSTORMS ARE LIKELY TO ACCOMPANY THE FRONTAL PASSAGE. AFTER
THIS...THERE IS INCREASING CONFIDENCE IN DRY WEATHER FOR MONDAY AND
PROBABLY SUNDAY AS HIGH PRESSURE BUILDS IN FROM THE WEST.
TEMPERATURES WILL START OFF WELL ABOVE NORMAL...AS OUR REGION WILL
START OFF THE PERIOD IN THE WARM SECTOR. FORECAST IS ABOVE MOS BASED
GUIDANCE...WHICH IS LIKELY TOO COOL IN THIS UNSEASONABLY WARM
ENVIRONMENT WHICH IS FORECAST TO RISE TO +16C AT 850MB. EXPECT HIGHS
TO TOP 80 DEGREES IN MANY LOCATIONS ON FRIDAY...WITH ONLY MINIMAL
COOLING FRIDAY NIGHT. EXPECT SEASONABLY COOL AIR BEHIND THE
FRONT...WITH DAYTIME HIGHS IN THE 60S ON SUNDAY AND MONDAY.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
CLEARING TREND CONTINUING TO WORK SOUTHWARD THIS EVENING. UNLIMITED
VFR CONDITIONS HAVE REACHED KIAG...KBUF...AND KART AS OF 00Z. KROC
WILL CLEAR COMPLETELY BY 02Z. IFR/MVFR CONDITIONS WILL PERSIST AT
KJHW THROUGH 03Z THEN CLEARING WILL TAKE PLACE HERE AS WELL WITH
VFR CONDITIONS EXPECTED BY 06Z. VFR CONDITIONS WILL THEN PREVAIL
THROUGH TUESDAY AS HIGH PRESSURE AND DRY AIR SETTLE OVER THE
REGION.
OUTLOOK...
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...VFR.
THURSDAY...VFR WITH A CHANCE OF SHOWERS ACROSS THE SOUTHERN TIER.
FRIDAY AND SATURDAY...VFR/MVFR WITH A CHANCE OF SHOWERS AND
THUNDERSTORMS.
&&
.MARINE...
HIGH PRESSURE BUILDING ACROSS THE LOWER GREAT LAKES OVERNIGHT. WINDS
AND WAVES WILL CONTINUE TO RELAX SO SMALL CRAFT ADVISORIES HAVE BEEN
DROPPED.
HIGH PRESSURE WILL REMAIN OVERHEAD TUESDAY...BEFORE DRIFTING
OFF THE EAST COAST WEDNESDAY AND THURSDAY. THIS WILL RESULT IN AN
EXTENDED PERIOD OF FAIR WEATHER FOR MIDWEEK...WITH WINDS AND WAVES
REMAINING BELOW ADVISORY LEVELS THROUGH AT LEAST THURSDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...FREEZE WARNING FROM 1 AM TO 8 AM EDT TUESDAY FOR NYZ007-008.
FROST ADVISORY FROM 1 AM TO 8 AM EDT TUESDAY FOR NYZ004>006-
012>014-019>021-085.
MARINE...NONE.
&&
$$
SYNOPSIS...JJR
NEAR TERM...JJR/SMITH
SHORT TERM...APFFEL
LONG TERM...APFFEL
AVIATION...JJR/TMA
MARINE...JJR/SMITH
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
351 PM EDT SUN SEP 15 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE REGION TONIGHT INTO MONDAY
MORNING WITH SCATTERED TO NUMEROUS SHOWERS. BEHIND THIS FRONT MUCH
COOLER AIR WILL FILTER INTO THE REGION WITH A WIDESPREAD FROST OR
FREEZING CONDITIONS EXPECTED AWAY FROM LAKE CHAMPLAIN MONDAY NIGHT.
THEREAFTER...LARGE SURFACE HIGH PRESSURE WILL BRING FAIR WEATHER
AND GRADUALLY WARMING TEMPERATURES TO THE AREA THROUGH THE
REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 330 PM EDT SUNDAY...FORECAST REMAINS IN GOOD SHAPE AS WE
PROGRESS INTO THE EVENING AND OVERNIGHT HOURS. STILL WATCHING A
STRONG EARLY SEASON COLD FRONT PROGRESSING STEADILY SOUTH AND EAST
TOWARD OUR AREA FROM SOUTH CENTRAL CANADA AND PER CURRENT
OBSERVATIONAL TRENDS EXPECT THE BOUNDARY TO ENTER OUR NORTHERN
ZONES LATER THIS EVENING AND PROGRESS FURTHER SOUTH THROUGH THE
OVERNIGHT/EARLY MORNING HOURS. DECENT FRONTAL ZONE CONVERGENCE
ALONG WITH A NARROW PWAT AXIS OF AROUND 1 INCH BOOSTS CONFIDENCE
THAT MOST OF OUR CENTRAL AND NORTHERN COUNTIES WILL SEE
MEASUREABLE LIGHT PCPN WITH THE PASSAGE OF THIS FEATURE. THUS HAVE
BOOSTED POPS INTO THE SOLID LIKELY (60-70%)...TO LOW END
CATEGORICAL RANGE (~80%) IN THE CASE OF THE NRN MTNS LATER TONIGHT
THROUGH MID-MORNING ON MONDAY. POPS LESS ACROSS THE SOUTH AS THE
FRONT ARRIVES LATER AND EVIDENCE THAT AFORMENTIONED LOW LEVEL
CONVERGENCE WILL WEAKEN AS THE BOUNDARY PRESSES SOUTH. AS
MENTIONED YESTERDAY...LOWS A BIT TRICKY GIVEN FRONTAL PASSAGE WILL
OCCUR WITHIN A FEW HOURS OF SUNRISE AND AMBIENT CLOUD COVER WILL
ACT TO INITIALLY OFFSET STRONGER COLD THERMAL ADVECTION. THUS A
BLEND OF AVAILABLE GUIDANCE ALONG WITH BIAS-CORRECTION STILL
APPEARS THE MOST REASONABLE COURSE OFFERING MINS FROM THE MID 40S
THE LOWER 50S.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 330 PM EDT SUNDAY...SHOWERS TO THEN END NORTH TO SOUTH
THROUGH THE MORNING HOURS ON MONDAY AS SFC FRONT QUICKLY CLEARS
SOUTH AND EAST OF OUR AREA. LINGERING POST-FRONTAL MOISTURE AND
BLOCKED LOW TO MID LEVEL FLOW SHOULD ENSURE COLD THERMAL ADVECTION
STRATOCUMULUS SHOULD PERSIST ACROSS MUCH OF THE AREA AT LEAST INTO
THE EARLY TO MID AFTERNOON HOURS BEFORE PARTIAL SUN DEVELOPS LATE.
BLENDED MODEL MEAN 850 MB TEMPERATURES FALL SLOWLY BUT STEADILY
THROUGH THE DAY TO AROUND 0C BY EARLY EVENING AND WITH MODESTLY
GUSTY NORTHWESTELY FLOW THERE WILL DEFINITELY BE A FALL-LIKE CHILL
IN THE AIR. GIVEN THESE FACTORS HAVE LEANED ON THE COLDER SIDE OF
AVBL TEMPERATURE GUIDANCE SHOWING READINGS CLIMBING ONLY SOME 3 TO
7 DEGREES ABOVE OVERNIGHT LOWS...OR TOPPING OUT MAINLY IN THE 50S.
A FEW SPOTS IN THE NORTHERN MOUNTAINS MAY STRUGGLE TO HIT 50 WHILE
AFTERNOON DOWNSLOPE FLOW SHOULD PUSH SOME LOCALES ACROSS
SOUTHEASTERN VT INTO THE LOWER 60S.
SKIES THEN GRADUALLY TREND CLEAR BY MONDAY NIGHT AS WINDS SLOWLY
RELAX AND STRONG 1030 HPA CANADIAN HIGH PRESSURE BUILDS INTO THE
REGION. WITH IDEAL RADIATIVE EFFECTS EXPECTED...WIDESPREAD FROSTY TO
FREEZING CONDITIONS ARE EXPECTED IN MOST AREAS AWAY FROM LAKE
CHAMPLAIN. NO HEADLINES WITH THIS PACKAGE...BUT CONFIDENCE IS HIGH
THAT THE GROWING SEASON WILL END FOR MANY BY TUESDAY MORNING. IN
FACT A FEW SPOTS MAY APPROACH RECORD LOWS FOR THE DATE...NOT A
TOPIC DISCUSSED IN OUR AREA TOO OFTEN THESE DAYS. PATCHY FOG ALSO A
GOOD BET HERE AND THERE...ESP IN THE MILDER LOCATIONS.
THEREAFTER...DEEP LAYER HIGH PRESSURE SLOWLY SETTLES ACROSS THE
REGION WITH FAIR AND SEASONABLY COOL WEATHER FOR TUESDAY INTO
TUESDAY NIGHT. STILL COULD SEE SOME PATCHY FROST/FOG BY EARLY
WEDNESDAY MORNING...ESP IN THE NORTHERN MTN HOLLOWS...BUT DEVELOPING
LIGHT RETURN FLOW LATER AT NIGHT SHOULD HOLD TEMPERATURES UP A FEW
THAN 24 HOURS PRIOR.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 350 PM EDT SUNDAY...MUCH BETTER AGREEMENT WITH LARGE SCALE
PATTERN FOR LATE WEEK INTO NEXT WEEKEND ASSOCIATED WITH DEVELOPMENT
OF MID/UPPER LVL AND TRACKING OF SFC COLD FRNT.
OVERALL...ECMWF/GEM HAS TRENDED TWD THE GFS WITH A
FAST/PROGRESSIVE MID/UPPER LVL PATTERN...WITH GREATEST THREAT OF
SHOWERS ON SATURDAY. THE 12Z ECMWF STILL SUPPORTS THE POTENTIAL
FOR A FEW LIGHT RAIN SHOWERS ASSOCIATED WITH A SFC WARM FRNT LATE
FRIDAY...AS PRE FRONTAL VORT INTERACTS WITH SOME 850 TO 500MB RH.
HOWEVER...THINKING INITIAL SURGE OF MOISTURE WL DISSIPATE AS IT
ENCOUNTERS DEEP DRY LAYER ASSOCIATED WITH STRONG MID/UPPER LVL
RIDGE ACRS THE EASTERN CONUS. WL KEEP FRIDAY DRY ATTM...AND
MENTION HIGHEST CHC POPS ON SATURDAY/SATURDAY NIGHT. BOTH
GFS/ECMWF SHOW A NARROW RIBBON OF ENHANCED 850 TO 500MB RH...ALONG
WITH FAVORABLE LIFT...RESULTING IN ONLY A BRIEF 3 TO 6 HOUR WINDOW
OF SHOWERS.
OTHERWISE...WEDS THRU FRIDAY OF THIS UPCOMING WEEK WL
BE DRY WITH RIDGE OF HIGH PRES DOMINATING ACRS THE NE CONUS.
PROGGED 85H TEMPS START BTWN 4-6C ON WEDS...BUT WARM TO 11-13C BY
18Z SATURDAY...SUPPORTING A TREND OF ABOVE NORMAL TEMPS BY LATE
WEEK INTO NEXT WEEKEND. GIVEN THE WARM THERMAL PROFILES WL TREND
TEMPS ABOVE NORMAL WITH VALUES BACK INTO THE 70S...MAYBE NEAR 80
IN THE WARMER VALLEYS BY SATURDAY...DEPENDING UPON CLOUD COVER.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
THROUGH 18Z MONDAY...CRNT SFC ANALYSIS PLACES A COLD FRNT ACRS
CENTRAL CANADA INTO THE CENTRAL GREAT LAKES ATTM...WITH GENERAL
MOVEMENT TWD THE EAST. THIS FRNT WL PRODUCE A 2 TO 6 HR WINDOW OF
-SHRA...ALONG WITH A POTENTIAL PERIOD OF MVFR/IFR CIGS ON MONDAY
MORNING...ESPECIALLY AT SLK/MPV. LOCAL HI RES MODEL REFLECTIVITY
AND LATEST 15Z RAP REFLECTIVITY PROGGS SHOW INITIAL BAND OF PRECIP
WL FALL MAINLY AS VIRGA THIS EVENING...DUE TO VERY DRY LLVLS...BUT
EXPECT -SHRA WITH NO VIS RESTRICTIONS TO DEVELOP AT MSS BY
01Z...AND INTO THE CPV BY 04Z...AND INTO AFT MIDNIGHT. GIVEN
UPSTREAM OBS OF IFR CONDITIONS BEHIND THE SFC FRNT...EXPECT A
PERIOD OF POST FRONTAL LOW CLOUDS/BR/-RA BTWN 10Z-16Z
MONDAY...WITH PERIODS OF IFR LIKELY...ESPECIALLY AT MPV/SLK. THE
COMBINATION OF UPSLOPE FLW...LEFTOVER SFC TO 850MB MOISTURE BEHIND
THE BOUNDARY...AND UPSTREAM OBS SUPPORTS THIS POTENTIAL.
OTHERWISE...SOUTH/SOUTHWEST WINDS WL SHIFT TO THE NORTH/NORTHWEST
BTWN 04-10Z TONIGHT...AND SLOWLY TO THE NORTHEAST BY MIDDAY MONDAY
AS SFC HIGH PRES BUILDS OUR TAF SITES.
OUTLOOK 18Z MONDAY THROUGH FRIDAY...ANY LINGERING STRATUS DECK BTWN
1500 AND 3000 KFT WL SLOWLY LIFT MONDAY AFTN...AS NORTH WINDS
ADVECT DRIER AIR INTO OUR TAF SITES. SFC HIGH PRES WL RESULT IN
VFR CONDITIONS FOR TUES THROUGH THURSDAY...WITH THE EXCEPTION OF
DAILY MORNING FOG AND LIFR CONDITION AT SLK/MPV. FOG COULD BE
WIDESPREAD ON TUESDAY MORNING...GIVEN LIGHT WINDS AND CLR SKIES
WITH AREAS OF FREEZING FOG POSSIBLE AT SLK/MPV. CLOUDS AND THE
THREAT OF SHOWERS INCREASES ON FRIDAY ASSOCIATED WITH OUR NEXT
SYSTEM...BUT VFR CONDITIONS SHOULD PREVAIL.
&&
.CLIMATE...
BELOW ARE RECORD LOW TEMPERATURES FOR TUESDAY SEPTEMBER 17.
LOCN RECORD DATE
KBTV 34F 1961
KMPV 29F 1948
KMSS 30F 1973
K1V4 29F 1959
&&
.EQUIPMENT...
AS OF 330 PM EDT SUNDAY...NOAA WEATHER RADIO STATION WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR DUE TO A DAMAGED ANTENNA. REPLACEMENT PARTS ARE ORDERED
AND THE REPAIR WORK HAS BEEN SCHEDULED FOR SEPTEMBER 17-20.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG
SHORT TERM...JMG
LONG TERM...TABER
AVIATION...TABER
CLIMATE...JMG
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
330 PM EDT SUN SEP 15 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE REGION TONIGHT INTO MONDAY
MORNING WITH SCATTERED TO NUMEROUS SHOWERS. BEHIND THIS FRONT MUCH
COOLER AIR WILL FILTER INTO THE REGION WITH A WIDESPREAD FROST OR
FREEZING CONDITIONS EXPECTED AWAY FROM LAKE CHAMPLAIN MONDAY NIGHT.
THEREAFTER...LARGE SURFACE HIGH PRESSURE WILL BRING FAIR WEATHER
AND GRADUALLY WARMING TEMPERATURES TO THE AREA THROUGH THE
REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 330 PM EDT SUNDAY...FORECAST REMAINS IN GOOD SHAPE AS WE
PROGRESS INTO THE EVENING AND OVERNIGHT HOURS. STILL WATCHING A
STRONG EARLY SEASON COLD FRONT PROGRESSING STEADILY SOUTH AND EAST
TOWARD OUR AREA FROM SOUTH CENTRAL CANADA AND PER CURRENT
OBSERVATIONAL TRENDS EXPECT THE BOUNDARY TO ENTER OUR NORTHERN
ZONES LATER THIS EVENING AND PROGRESS FURTHER SOUTH THROUGH THE
OVERNIGHT/EARLY MORNING HOURS. DECENT FRONTAL ZONE CONVERGENCE
ALONG WITH A NARROW PWAT AXIS OF AROUND 1 INCH BOOSTS CONFIDENCE
THAT MOST OF OUR CENTRAL AND NORTHERN COUNTIES WILL SEE
MEASUREABLE LIGHT PCPN WITH THE PASSAGE OF THIS FEATURE. THUS HAVE
BOOSTED POPS INTO THE SOLID LIKELY (60-70%)...TO LOW END
CATEGORICAL RANGE (~80%) IN THE CASE OF THE NRN MTNS LATER TONIGHT
THROUGH MID-MORNING ON MONDAY. POPS LESS ACROSS THE SOUTH AS THE
FRONT ARRIVES LATER AND EVIDENCE THAT AFORMENTIONED LOW LEVEL
CONVERGENCE WILL WEAKEN AS THE BOUNDARY PRESSES SOUTH. AS
MENTIONED YESTERDAY...LOWS A BIT TRICKY GIVEN FRONTAL PASSAGE WILL
OCCUR WITHIN A FEW HOURS OF SUNRISE AND AMBIENT CLOUD COVER WILL
ACT TO INITIALLY OFFSET STRONGER COLD THERMAL ADVECTION. THUS A
BLEND OF AVAILABLE GUIDANCE ALONG WITH BIAS-CORRECTION STILL
APPEARS THE MOST REASONABLE COURSE OFFERING MINS FROM THE MID 40S
THE LOWER 50S.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 330 PM EDT SUNDAY...SHOWERS TO THEN END NORTH TO SOUTH
THROUGH THE MORNING HOURS ON MONDAY AS SFC FRONT QUICKLY CLEARS
SOUTH AND EAST OF OUR AREA. LINGERING POST-FRONTAL MOISTURE AND
BLOCKED LOW TO MID LEVEL FLOW SHOULD ENSURE COLD THERMAL ADVECTION
STRATOCUMULUS SHOULD PERSIST ACROSS MUCH OF THE AREA AT LEAST INTO
THE EARLY TO MID AFTERNOON HOURS BEFORE PARTIAL SUN DEVELOPS LATE.
BLENDED MODEL MEAN 850 MB TEMPERATURES FALL SLOWLY BUT STEADILY
THROUGH THE DAY TO AROUND 0C BY EARLY EVENING AND WITH MODESTLY
GUSTY NORTHWESTELY FLOW THERE WILL DEFINITELY BE A FALL-LIKE CHILL
IN THE AIR. GIVEN THESE FACTORS HAVE LEANED ON THE COLDER SIDE OF
AVBL TEMPERATURE GUIDANCE SHOWING READINGS CLIMBING ONLY SOME 3 TO
7 DEGREES ABOVE OVERNIGHT LOWS...OR TOPPING OUT MAINLY IN THE 50S.
A FEW SPOTS IN THE NORTHERN MOUNTAINS MAY STRUGGLE TO HIT 50 WHILE
AFTERNOON DOWNSLOPE FLOW SHOULD PUSH SOME LOCALES ACROSS
SOUTHEASTERN VT INTO THE LOWER 60S.
SKIES THEN GRADUALLY TREND CLEAR BY MONDAY NIGHT AS WINDS SLOWLY
RELAX AND STRONG 1030 HPA CANADIAN HIGH PRESSURE BUILDS INTO THE
REGION. WITH IDEAL RADIATIVE EFFECTS EXPECTED...WIDESPREAD FROSTY TO
FREEZING CONDITIONS ARE EXPECTED IN MOST AREAS AWAY FROM LAKE
CHAMPLAIN. NO HEADLINES WITH THIS PACKAGE...BUT CONFIDENCE IS HIGH
THAT THE GROWING SEASON WILL END FOR MANY BY TUESDAY MORNING. IN
FACT A FEW SPOTS MAY APPROACH RECORD LOWS FOR THE DATE...NOT A
TOPIC DISCUSSED IN OUR AREA TOO OFTEN THESE DAYS. PATCHY FOG ALSO A
GOOD BET HERE AND THERE...ESP IN THE MILDER LOCATIONS.
THEREAFTER...DEEP LAYER HIGH PRESSURE SLOWLY SETTLES ACROSS THE
REGION WITH FAIR AND SEASONABLY COOL WEATHER FOR TUESDAY INTO
TUESDAY NIGHT. STILL COULD SEE SOME PATCHY FROST/FOG BY EARLY
WEDNESDAY MORNING...ESP IN THE NORTHERN MTN HOLLOWS...BUT DEVELOPING
LIGHT RETURN FLOW LATER AT NIGHT SHOULD HOLD TEMPERATURES UP A FEW
THAN 24 HOURS PRIOR.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 331 AM EDT SUNDAY...DEEP-LAYER RIDGE FIRMLY ESTABLISHED
ACROSS THE NORTHEAST CONUS BRINGS DRY AND QUIET WEATHER TO START
THE PERIOD RIGHT THRU THURSDAY NIGHT. AIR MASS GRADUALLY MODERATES
THRU THE PERIOD...WITH VALLEY HIGHS NEAR 70F ON WEDNESDAY AND INTO
THE LOW-MID 70S FOR THURSDAY AND FRIDAY. COULD SEE SOME PATCHY
VALLEY FOG TUESDAY AND WEDNESDAY NIGHT (MAINLY 06-12Z) ASSOCIATED
WITH LIGHT WINDS AND GOOD RADIATIVE COOLING CONDITIONS. SOME
DIFFERENCES BETWEEN THE 00Z ECMWF AND 00Z GFS WITH RESPECT TO
TIMING OF NEXT SHORTWAVE TROUGH FROM THE GREAT LAKES AND
ASSOCIATED WARM FRONT. THE ECMWF IS A BIT QUICKER...SUGGESTING
INCREASING CLOUDS AND DEVELOPING RAIN FRIDAY AFTN ACROSS NRN NY
AND DEVELOPING ACROSS VT FRIDAY NIGHT INTO SATURDAY MORNING. IN
CONTRAST THE 00Z GFS IS ABOUT 24 HOURS SLOWER...DOESN/T SHOW A
WARM FRONT WITH ANY QPF AWAITING ARRIVAL OF A COLD FRONT LATE IN
THE DAY SATURDAY. TOOK A COMPROMISE OF THE TWO SOLNS IN DERIVING
SKY/POPS. LOOKING AT A SLIGHT CHANCE OF -SHRA ACROSS THE ST.
LAWRENCE VALLEY FRIDAY AFTN...FOLLOWED BY 30-40 POPS AREAWIDE
FRIDAY NIGHT INTO SATURDAY. TEMPERATURE FORECAST GENERAL FOLLOWS A
50/50 BLEND OF MEX-MOS VALUES AND 14-DAY BIAS CORRECTION OF MEX-
MOS AND RESULTANT FORECAST IS ABOVE SEASONAL AVERAGES FOR MID-
SEPT.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
THROUGH 18Z MONDAY...CRNT SFC ANALYSIS PLACES A COLD FRNT ACRS
CENTRAL CANADA INTO THE CENTRAL GREAT LAKES ATTM...WITH GENERAL
MOVEMENT TWD THE EAST. THIS FRNT WL PRODUCE A 2 TO 6 HR WINDOW OF
-SHRA...ALONG WITH A POTENTIAL PERIOD OF MVFR/IFR CIGS ON MONDAY
MORNING...ESPECIALLY AT SLK/MPV. LOCAL HI RES MODEL REFLECTIVITY
AND LATEST 15Z RAP REFLECTIVITY PROGGS SHOW INITIAL BAND OF PRECIP
WL FALL MAINLY AS VIRGA THIS EVENING...DUE TO VERY DRY LLVLS...BUT
EXPECT -SHRA WITH NO VIS RESTRICTIONS TO DEVELOP AT MSS BY
01Z...AND INTO THE CPV BY 04Z...AND INTO AFT MIDNIGHT. GIVEN
UPSTREAM OBS OF IFR CONDITIONS BEHIND THE SFC FRNT...EXPECT A
PERIOD OF POST FRONTAL LOW CLOUDS/BR/-RA BTWN 10Z-16Z
MONDAY...WITH PERIODS OF IFR LIKELY...ESPECIALLY AT MPV/SLK. THE
COMBINATION OF UPSLOPE FLW...LEFTOVER SFC TO 850MB MOISTURE BEHIND
THE BOUNDARY...AND UPSTREAM OBS SUPPORTS THIS POTENTIAL.
OTHERWISE...SOUTH/SOUTHWEST WINDS WL SHIFT TO THE NORTH/NORTHWEST
BTWN 04-10Z TONIGHT...AND SLOWLY TO THE NORTHEAST BY MIDDAY MONDAY
AS SFC HIGH PRES BUILDS OUR TAF SITES.
OUTLOOK 18Z MONDAY THROUGH FRIDAY...ANY LINGERING STRATUS DECK BTWN
1500 AND 3000 KFT WL SLOWLY LIFT MONDAY AFTN...AS NORTH WINDS
ADVECT DRIER AIR INTO OUR TAF SITES. SFC HIGH PRES WL RESULT IN
VFR CONDITIONS FOR TUES THROUGH THURSDAY...WITH THE EXCEPTION OF
DAILY MORNING FOG AND LIFR CONDITION AT SLK/MPV. FOG COULD BE
WIDESPREAD ON TUESDAY MORNING...GIVEN LIGHT WINDS AND CLR SKIES
WITH AREAS OF FREEZING FOG POSSIBLE AT SLK/MPV. CLOUDS AND THE
THREAT OF SHOWERS INCREASES ON FRIDAY ASSOCIATED WITH OUR NEXT
SYSTEM...BUT VFR CONDITIONS SHOULD PREVAIL.
&&
.CLIMATE...
BELOW ARE RECORD LOW TEMPERATURES FOR TUESDAY SEPTEMBER 17.
LOCN RECORD DATE
KBTV 34F 1961
KMPV 29F 1948
KMSS 30F 1973
K1V4 29F 1959
&&
.EQUIPMENT...
AS OF 330 PM EDT SUNDAY...NOAA WEATHER RADIO STATION WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR DUE TO A DAMAGED ANTENNA. REPLACEMENT PARTS ARE ORDERED
AND THE REPAIR WORK HAS BEEN SCHEDULED FOR SEPTEMBER 17-20.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG
SHORT TERM...JMG
LONG TERM...BANACOS
AVIATION...TABER
CLIMATE...JMG
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
127 PM EDT SUN SEP 15 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE NORTHEAST REGION WILL GIVE WAY TO A
FRONTAL BOUNDARY LATER TONIGHT INTO MONDAY. PRECIPITATION WILL
TAPER OFF DURING THE AFTERNOON HOURS MONDAY...GIVING WAY TO HIGH
PRESSURE THROUGH THE END OF THE WEEK...BEFORE ANOTHER FRONT ARRIVAL
LATE FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1025 AM EDT SUNDAY...INHERITED FORECAST MORE OR LESS ON TRACK
AS OF LATE MORNING WITH ONLY MINOR TWEAKS TO SKY COVER NEEDED TO
MATCH CURRENT OBSERVATIONAL TRENDS. GENERALLY TRENDING PTLY SUNNY
FOR MOST AREAS TODAY UNDER INCREASING MID/HIGH LVL RH...THOUGH
THICKER CLOUD COVER LIKELY ACROSS THE SLV BY THIS AFTERNOON. SOME
GUSTY SOUTH/SOUTHWESTERLY FLOW ALSO LIKELY FROM THE CHVLY
WESTBOUND AS P-GRAD SLOWLY TIGHTENS BETWEEN DEPARTING SFC HIGH AND
APPROACHING COLD FRONT OFF TO OUR DISTANT NW (GUSTING TO 18 KT AT
KBTV). MODEL SOUNDINGS AND 925 MB THERMAL PROFILES SUPPORT HIGHS
MAINLY IN THE 60S TO AROUND 70 WHICH IS COVERED WELL AT THIS POINT
SO NO CHANGES NEEDED IN THAT REGARD. HAVE A GREAT DAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
AS OF 435 AM EDT SUNDAY...CLD COVER ON THE INCR BY THIS EVENING
AS NEXT FRONT APPROACHES FROM THE GREAT LKS REGION. MDLS CONTINUE
TO SHOW SLOW ONSET OF RAIN INTO THE AREA GOING INTO THE OVERNGT
HRS...AIDED BY SFC HIGH TO OUR SOUTH AND EAST BLOCKING ADVANCE
INITIALLY. MDLS DO BRING FRONT THRU THE CWA...BRINGING HIGHEST
POPS AFT 06Z MONDAY. WILL CONTINUE CURRENT TREND OF TAPERING -RW
OFF TOWARDS 12Z MONDAY FROM THE NW. OVERNGT LOWS WILL REMAIN
FAIRLY STABLE WITH LITTLE DROP DUE TO CLDS FROM FRNT.
FIRST HALF OF MONDAY WILL HAVE THE CWA CONTINUE TO SEE -RW FROM
EXITING FRNTL BOUNDARY WHICH WILL EXIT TO OUR SE BY THE AFTNOON
HRS. OVERALL QPF FROM FROPA AROUND 0.10-0.20". CLRING EXPECTED
FROM NW TO SE AS A RESULT WITH SFC HIGH PRESSURE EAST FROM THE
GREAT LKS REGION. CAA BROUGHT DOWN FROM NNW WINDS 10-20 MPH AHEAD
OF THE APPROACHING RIDGE WILL AID TO DROP OVERNGT LOWS MON NGT TO
MAINLY IN THE 30S W/ SOME 20S IN HIR ELEV. WITH CLR SKIES...CALM
WINDS ACCOMPANYING THIS CD AIRMASS...EXPECTING MANY SPOTS TO SEE
PATCHY/AREAS OF FROST MAINLY AFT 06Z TUES WHEN MDLS BRING RIDGE
CRESTING OVER MOST OF CWA. NO HEADLINES ISSUED ATTM FOR FROST
ADVISORY BUT MAY BE ISSUED LATER TODAY. CD NIGHT MONDAY WILL GIVE
WAY TO A GREAT SUNNY DAY ON TUESDAY AS SFC RIDGE PUSHES OFF THE
NEW ENGLAND COAST. BULK OF WAA ON SSW FLOW REMAINS JUST OFF TO OUR
WEST IN THE GREAT LKS REGION...SO WILL KEEP HIGH TEMPS MAINLY IN
THE 60S...WHICH WILL BE BLW NORMAL FOR MANY LOCALES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 331 AM EDT SUNDAY...DEEP-LAYER RIDGE FIRMLY ESTABLISHED
ACROSS THE NORTHEAST CONUS BRINGS DRY AND QUIET WEATHER TO START
THE PERIOD RIGHT THRU THURSDAY NIGHT. AIR MASS GRADUALLY MODERATES
THRU THE PERIOD...WITH VALLEY HIGHS NEAR 70F ON WEDNESDAY AND INTO
THE LOW-MID 70S FOR THURSDAY AND FRIDAY. COULD SEE SOME PATCHY
VALLEY FOG TUESDAY AND WEDNESDAY NIGHT (MAINLY 06-12Z) ASSOCIATED
WITH LIGHT WINDS AND GOOD RADIATIVE COOLING CONDITIONS. SOME
DIFFERENCES BETWEEN THE 00Z ECMWF AND 00Z GFS WITH RESPECT TO
TIMING OF NEXT SHORTWAVE TROUGH FROM THE GREAT LAKES AND
ASSOCIATED WARM FRONT. THE ECMWF IS A BIT QUICKER...SUGGESTING
INCREASING CLOUDS AND DEVELOPING RAIN FRIDAY AFTN ACROSS NRN NY
AND DEVELOPING ACROSS VT FRIDAY NIGHT INTO SATURDAY MORNING. IN
CONTRAST THE 00Z GFS IS ABOUT 24 HOURS SLOWER...DOESN/T SHOW A
WARM FRONT WITH ANY QPF AWAITING ARRIVAL OF A COLD FRONT LATE IN
THE DAY SATURDAY. TOOK A COMPROMISE OF THE TWO SOLNS IN DERIVING
SKY/POPS. LOOKING AT A SLIGHT CHANCE OF -SHRA ACROSS THE ST.
LAWRENCE VALLEY FRIDAY AFTN...FOLLOWED BY 30-40 POPS AREAWIDE
FRIDAY NIGHT INTO SATURDAY. TEMPERATURE FORECAST GENERAL FOLLOWS A
50/50 BLEND OF MEX-MOS VALUES AND 14-DAY BIAS CORRECTION OF MEX-
MOS AND RESULTANT FORECAST IS ABOVE SEASONAL AVERAGES FOR MID-
SEPT.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
THROUGH 18Z MONDAY...CRNT SFC ANALYSIS PLACES A COLD FRNT ACRS
CENTRAL CANADA INTO THE CENTRAL GREAT LAKES ATTM...WITH GENERAL
MOVEMENT TWD THE EAST. THIS FRNT WL PRODUCE A 2 TO 6 HR WINDOW OF
-SHRA...ALONG WITH A POTENTIAL PERIOD OF MVFR/IFR CIGS ON MONDAY
MORNING...ESPECIALLY AT SLK/MPV. LOCAL HI RES MODEL REFLECTIVITY
AND LATEST 15Z RAP REFLECTIVITY PROGGS SHOW INITIAL BAND OF PRECIP
WL FALL MAINLY AS VIRGA THIS EVENING...DUE TO VERY DRY LLVLS...BUT
EXPECT -SHRA WITH NO VIS RESTRICTIONS TO DEVELOP AT MSS BY
01Z...AND INTO THE CPV BY 04Z...AND INTO AFT MIDNIGHT. GIVEN
UPSTREAM OBS OF IFR CONDITIONS BEHIND THE SFC FRNT...EXPECT A
PERIOD OF POST FRONTAL LOW CLOUDS/BR/-RA BTWN 10Z-16Z
MONDAY...WITH PERIODS OF IFR LIKELY...ESPECIALLY AT MPV/SLK. THE
COMBINATION OF UPSLOPE FLW...LEFTOVER SFC TO 850MB MOISTURE BEHIND
THE BOUNDARY...AND UPSTREAM OBS SUPPORTS THIS POTENTIAL.
OTHERWISE...SOUTH/SOUTHWEST WINDS WL SHIFT TO THE NORTH/NORTHWEST
BTWN 04-10Z TONIGHT...AND SLOWLY TO THE NORTHEAST BY MIDDAY MONDAY
AS SFC HIGH PRES BUILDS OUR TAF SITES.
OUTLOOK 18Z MONDAY THROUGH FRIDAY...ANY LINGERING STRATUS DECK BTWN
1500 AND 3000 KFT WL SLOWLY LIFT MONDAY AFTN...AS NORTH WINDS
ADVECT DRIER AIR INTO OUR TAF SITES. SFC HIGH PRES WL RESULT IN
VFR CONDITIONS FOR TUES THROUGH THURSDAY...WITH THE EXCEPTION OF
DAILY MORNING FOG AND LIFR CONDITION AT SLK/MPV. FOG COULD BE
WIDESPREAD ON TUESDAY MORNING...GIVEN LIGHT WINDS AND CLR SKIES
WITH AREAS OF FREEZING FOG POSSIBLE AT SLK/MPV. CLOUDS AND THE
THREAT OF SHOWERS INCREASES ON FRIDAY ASSOCIATED WITH OUR NEXT
SYSTEM...BUT VFR CONDITIONS SHOULD PREVAIL.
&&
.EQUIPMENT...
AS OF 435 AM EDT SUNDAY...NOAA WEATHER RADIO STATION WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR DUE TO A DAMAGED ANTENNA. REPLACEMENT PARTS ARE ORDERED
AND THE REPAIR WORK HAS BEEN SCHEDULED FOR SEPTEMBER 17-20.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JN
NEAR TERM...JMG
SHORT TERM...JN
LONG TERM...BANACOS
AVIATION...TABER
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION...CORRECTED
NWS WILMINGTON NC
1019 PM EDT MON SEP 16 2013
.SYNOPSIS...
HIGH PRESSURE ACROSS THE GREAT LAKES WILL PUSH A COLD FRONT SOUTH
ACROSS THE CAROLINAS TONIGHT. THE HIGH WILL WEAKEN SLOWLY AS IT
PUSHES OFF THE EAST COAST THURSDAY AND FRIDAY. WARMER AND MORE
HUMID WEATHER IS EXPECTED THIS WEEKEND AHEAD OF ANOTHER COLD FRONT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 10 PM MONDAY...A COLD FRONT WAS MAKING GOOD SOUTHWARD PROGRESS
THIS EVE. THE FRONT AND ITS PROGRESSION WAS CLEARLY VISIBLE ON RADAR
LOOPS AND WAS JUST S OF A LBT-EYF-WATHA LINE. IT WAS MOVING S JUST
OVER 20 MPH. THIS WILL PUT THE FRONT S OF THE SOUTH SANTEE RIVER
BETWEEN 3 AND 4 AM. THE WIND WILL SHIFT TO THE N AND THEN NE BEHIND
THE FRONT AND INCREASE AS DRIER AND COOLER AIR SURGES SOUTH AND
ACROSS THE FORECAST AREA OVERNIGHT AND ON TUE.
SCATTERED SHOWERS WILL MOVE S WITH THE FRONT AND WE HAVE SHOWN POPS
DROPPING BELOW THRESHOLD AFTER FRONTAL PASSAGE. HAVE REMOVED MENTION
OF THUNDER. HEAVY RAIN IS NO LONGER EXPECTED...AND THE DURATION OF
ANY RAIN OVERNIGHT WILL BE BRIEF...AMOUNTING TO LESS THAN A TENTH OF
AN INCH.
AN UPPER TROUGH WILL SWING ACROSS THE FORECAST AREA OVERNIGHT AND
TUE MORNING AND THIS WILL ENHANCE THE SURGE OF DRY AND COOL AIR.
EXPECT SUSTAINED NE WINDS WILL INCREASE UP TO 15 MPH WITH HIGHER
GUSTS. THIS SURGE WILL DROP THE DEWPOINTS INTO THE UPPER 50S BY
SUNRISE ACROSS THE N...AND THROUGH THE 60S ELSEWHERE. THE WINDS WILL
PROVIDE A WELL MIXED ENVIRONMENT...AND SO TEMPS WILL NOT FALL OFF
SIGNIFICANTLY OVERNIGHT AND WILL ACTUALLY BE SIMILAR TO THE LOWS
EXPERIENCED THIS MORNING. MID AND UPPER 60S WILL BE COMMON ACROSS
THE NORTHERN TWO-THIRDS OF THE AREA WITH UPPER 60S TO AROUND 70
DEGREES ACROSS THE SOUTHERN THIRD.
SKIES WILL BECOME OR CONTINUE MOSTLY CLOUDY FOR THE REMAINDER OF THE
NIGHT. A TREND TOWARD CLEARER SKIES WILL HAVE TO WAIT UNTIL TUE.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 230 PM MONDAY...THE MID LEVEL FLOW WILL START OUT WITH A
PROGRESSIVE TROUGH MOVING OFFSHORE WITH THE PATTERN RELAXING
SLIGHTLY THROUGH WEDNESDAY. ANOTHER WEAK SHORTWAVE WILL TURN THE
FLOW TO THE NORTHWEST ONCE AGAIN EARLY THURSDAY. AT THE
SURFACE...HIGH PRESSURE WILL BUILD DOWN FROM THE NORTH/NORTHEAST AND
WITH PRECIPITABLE WATER VALUES FALLING DOWN TO WELL BELOW ONE
INCH...POPS WILL NOT BE AN ISSUE THROUGH THE PERIOD.
THE LATEST NUMERICAL GUIDANCE HAS TRENDED COOLER WITH TEMPERATURES
THROUGH THE PERIOD. I DID GO SLIGHTLY ABOVE THE NUMBERS FOR
WEDNESDAYS LOWS DUE TO THE BOUNDARY LAYER REMAINING MIXED. FOR THIS
REASON THURSDAYS LOWS COULD BE JUST ABOUT THE SAME DUE TO MORE
FAVORABLE RADIATIONAL CONDITIONS DESPITE SOME AIRMASS
MODIFICATION...OTHERWISE I STAYED NEAR GUIDANCE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 230 PM MONDAY...HIGH PRESSURE EXTENDING DOWN THE COAST
COMBINES WITH 5H RIDGING INTO THE WEEKEND TO CREATE SEASONABLE AND
DRY WEATHER ACROSS THE LOCAL AREA. WITH HIGH CENTERED OVER NEW
ENGLAND...SURFACE RIDGE AXIS WILL ONLY GRADUALLY DRIFT EAST...SO
COOL NE FLOW WILL PERSIST THURSDAY BEFORE SLOWLY VEERING AROUND TO
THE SOUTH BY SATURDAY. WHILE THIS VEERING OF WIND WILL CAUSE AIR
MASS MODIFICATION AND WARMING...IT WILL BE SOMEWHAT OFFSET BY
LOWERING MID-LEVEL THICKNESSES IN RESPONSE TO A STRONG POLAR VORTEX
MOVING ACROSS THE GREAT LAKES. THUS...TEMPS WILL RISE FROM JUST
BELOW CLIMO THURSDAY...TO RIGHT AROUND OR SLIGHTLY ABOVE SATURDAY.
COLD FRONT BEING PUSHED SOUTH BY THE AFOREMENTIONED VORTEX WILL MOVE
TOWARDS THE AREA SUNDAY...CROSSING SOUTH BY SUNDAY NIGHT. WHILE
GUIDANCE IS IN BETTER AGREEMENT IN TIMING OF THIS FEATURE...IT STILL
LOOKS TO BE RATHER WEAK WITH LIMITED MOISTURE ADVECTION AHEAD OF
IT...AND LITTLE TEMP DIFFERENTIAL ALONG IT. WILL CONTINUE INHERITED
SCHC POP FOR SUNDAY HOWEVER...AND THIS WILL BE THE ONLY REAL PRECIP
CHANCE FOR THE EXTENDED. MID-LEVEL RIDGING QUICKLY REBUILDS BEHIND
THIS BOUNDARY AS IT STALLS AND ERODES JUST SOUTH OF THE CWA
MONDAY...RETURNING DRY AND SEASONABLE CONDITIONS TO THE CAROLINAS.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 00Z...MOST OF THE CONVECTION HAS ENDING...HOWEVER THE FRONT IS
STILL 3-5 HOURS AWAY. THE HRRR MODEL SHOWS A BAND OF MODERATE
SHOWERS OVER THE EASTERN THIRD OF NORTH CAROLINA...PRETTY MUCH ALONG
THE FRONTAL BOUNDARY. ATMOSPHERE HAS BEEN WORKED OVER
MODERATELY...SO THINK ANY FRONTAL CONVECTION WILL BE LIGHT...AND
LAST ONLY AN HOUR OR TWO. BEST CHANCE WILL BE AT ILM WHERE SOME
LEFTOVER INSTABILITY MAY STILL EXIST. WINDS WILL SHIFT TO THE
NORTHEAST...POST FRONTAL. WITH NORTHEAST WINDS EXPECTED AT ALL
TERMINALS AFTER 07Z. WINDS WILL BECOME GUSTY BY DAYBREAK AS MIXING
BEGINS WITH A MODERATE PRESSURE GRADIENT. THE NAM IS ADVERTISING
SOME BRIEF IFR CEILINGS TOWARD MORNING...BUT AM NOT BUYING THIS
SCENARIO AT THIS TIME.
EXTENDED OUTLOOK...EXPECT VFR THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10 PM MONDAY...A COLD FRONT WILL MOVE ACROSS THE WATERS
OVERNIGHT...SHIFTING WINDS FROM SW TO N AND THEN NE. A NE SURGE
WILL FOLLOW AS COOL AND DRY AIR RUSHES DOWN THE COAST. THIS SURGE
WILL REACH THE NORTHERN WATERS 07-09Z AND THE SOUTHERN WATERS
08-10Z. THE SURGE WILL CONTINUE THROUGH TUE. SUSTAINED NE WINDS WILL
INCREASE TO 15 TO 20 KT OVERNIGHT. SEAS WILL BUILD TO 4 TO 5 FT
TOWARD DAYBREAK AND THEN INCREASE ANOTHER 1 TO 2 FT TUE MORNING.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 230 PM MONDAY...NORTHEAST WINDS WILL BE THE THEME OF THE SHORT
TERM FORECAST AS HIGH PRESSURE SLOWLY MOVES FROM NEW YORK TO
ESSENTIALLY OFF THE DELMARVA. WINS SPEEDS TUESDAY WILL BE 15-20
KNOTS AND VERY SLOWLY WORK DOWN TO 10-15 KNOTS BY THURSDAY AM. I
HAVE RAISED A SMALL CRAFT ADVISORY FOR ALL WATERS FOR TUESDAY WELL
INTO THE EVENING DUE TO SEAS OF SIX FEET. WITH THE DECREASE IN
WINDS...SEAS SHOULD SETTLE DOWN INTO A 2-4 FOOT RANGE LATER
WEDNESDAY.
LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 230 PM MONDAY...RIDGE OF HIGH PRESSURE EXTENDING DOWN THE EAST
COAST WILL GRADUALLY WEAKEN AND MOVE AWAY INTO THE WEEKEND...CAUSING
DECREASING WINDS THROUGH THE PERIOD. INITIALLY...NE WINDS OF 10-15
KTS WILL OCCUR ACROSS THE WATERS...BUT THESE WILL EASE TO LESS THAN
10 KTS FRIDAY AS THE PRESSURE GRADIENT WEAKENS...AND THEN BECOME
LIGHT AND VARIABLE ON SATURDAY AS RETURN FLOW BEGINS TO DEVELOP.
WAVE HEIGHTS WILL RESPOND TO THE EASING WINDS...FALLING FROM 2-4 FT
THURSDAY...TO 1-3 FT FRIDAY AND SATURDAY. A WAVE SHADOWED REGION
WILL EXIST THU/FRI ALONG THE BRUNSWICK COUNTY COAST...WHERE WAVE
HEIGHTS WILL BE ONLY AROUND 1-2 FT NEAR SHORE BOTH DAYS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM TUESDAY TO 2 AM EDT WEDNESDAY
FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...RJD
SHORT TERM...SHK
LONG TERM...JDW
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
823 PM EDT MON SEP 16 2013
.SYNOPSIS...
HIGH PRESSURE ACROSS THE GREAT LAKES WILL PUSH A COLD FRONT SOUTH
ACROSS THE CAROLINAS TONIGHT. THE HIGH WILL WEAKEN SLOWLY AS IT
PUSHES OFF THE EAST COAST THURSDAY AND FRIDAY. WARMER AND MORE
HUMID WEATHER IS EXPECTED THIS WEEKEND AHEAD OF ANOTHER COLD FRONT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 7 PM MONDAY...ONGOING CONVECTION WAS EITHER WINDING DOWN OR
MOVING OFFSHORE EARLY THIS EVE. POPS WERE APPROPRIATELY RAISED TO
ACCOUNT FOR THE AREAS WHERE SHOWERS AND A FEW THUNDERSTORMS WILL BE
MOST LIKELY THROUGH THE EARLY EVE. A COLD FRONT WAS JUST BEGINNING
TO MOVE INTO THE NORTHERN REACHES OF THE FORECAST AREA AROUND
PARKTON AND AMMON AND WILL CONTINUE TO SURGE SOUTHWARD...CLEARING
THE AREAS AROUND THE SOUTH SANTEE RIVER PRIOR TO MIDNIGHT. THE UPPER
TROUGH WILL THEN SWEEP ACROSS THE FORECAST AREA OVERNIGHT. ALL OF
THE MODELS ARE CONSISTENT IN SHOWING SIGNIFICANT DRYING WILL NOT
TAKE PLACE UNTIL THE UPPER TROUGH IS OFFSHORE. THUS...HAVE OPTED TO
KEEP SMALL POPS IN THE FORECAST LATE EVE AND OVERNIGHT TO ACCOUNT
FOR THIS. HOWEVER...NO HEAVY RAIN IS EXPECTED ACROSS THE FORECAST
AREA AFTER 9 PM OR SO. HOWEVER...A FLEETING RUMBLE OF THUNDER MAY
STILL OCCUR AFTER MIDNIGHT.
AS THE COOL AND DRY SURGE KICKS IN OVERNIGHT...SUSTAINED NE WINDS
WILL INCREASE TO AROUND 15 MPH WITH HIGHER GUSTS. THIS SURGE WILL
DROP THE DEWPOINTS INTO THE UPPER 50S BY SUNRISE ACROSS THE N...AND
THROUGH THE 60S ELSEWHERE. THE WINDS WILL PROVIDE A WELL MIXED
ENVIRONMENT...AND SO TEMPS WILL NOT FALL OFF SIGNIFICANTLY OVERNIGHT
AND WILL ACTUALLY BE SIMILAR TO THE LOWS THIS MORNING. MID AND UPPER
60S WILL BE COMMON ACROSS THE NORTHERN TWO-THIRDS OF THE AREA WITH
UPPER 60S TO AROUND 70 DEGREES ACROSS THE SOUTHERN THIRD. A TREND
TOWARD CLEARER SKIES WILL HAVE TO WAIT UNTIL TUE.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 230 PM MONDAY...THE MID LEVEL FLOW WILL START OUT WITH A
PROGRESSIVE TROUGH MOVING OFFSHORE WITH THE PATTERN RELAXING
SLIGHTLY THROUGH WEDNESDAY. ANOTHER WEAK SHORTWAVE WILL TURN THE
FLOW TO THE NORTHWEST ONCE AGAIN EARLY THURSDAY. AT THE
SURFACE...HIGH PRESSURE WILL BUILD DOWN FROM THE NORTH/NORTHEAST AND
WITH PRECIPITABLE WATER VALUES FALLING DOWN TO WELL BELOW ONE
INCH...POPS WILL NOT BE AN ISSUE THROUGH THE PERIOD.
THE LATEST NUMERICAL GUIDANCE HAS TRENDED COOLER WITH TEMPERATURES
THROUGH THE PERIOD. I DID GO SLIGHTLY ABOVE THE NUMBERS FOR
WEDNESDAYS LOWS DUE TO THE BOUNDARY LAYER REMAINING MIXED. FOR THIS
REASON THURSDAYS LOWS COULD BE JUST ABOUT THE SAME DUE TO MORE
FAVORABLE RADIATIONAL CONDITIONS DESPITE SOME AIRMASS
MODIFICATION...OTHERWISE I STAYED NEAR GUIDANCE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 230 PM MONDAY...HIGH PRESSURE EXTENDING DOWN THE COAST
COMBINES WITH 5H RIDGING INTO THE WEEKEND TO CREATE SEASONABLE AND
DRY WEATHER ACROSS THE LOCAL AREA. WITH HIGH CENTERED OVER NEW
ENGLAND...SURFACE RIDGE AXIS WILL ONLY GRADUALLY DRIFT EAST...SO
COOL NE FLOW WILL PERSIST THURSDAY BEFORE SLOWLY VEERING AROUND TO
THE SOUTH BY SATURDAY. WHILE THIS VEERING OF WIND WILL CAUSE AIR
MASS MODIFICATION AND WARMING...IT WILL BE SOMEWHAT OFFSET BY
LOWERING MID-LEVEL THICKNESSES IN RESPONSE TO A STRONG POLAR VORTEX
MOVING ACROSS THE GREAT LAKES. THUS...TEMPS WILL RISE FROM JUST
BELOW CLIMO THURSDAY...TO RIGHT AROUND OR SLIGHTLY ABOVE SATURDAY.
COLD FRONT BEING PUSHED SOUTH BY THE AFOREMENTIONED VORTEX WILL MOVE
TOWARDS THE AREA SUNDAY...CROSSING SOUTH BY SUNDAY NIGHT. WHILE
GUIDANCE IS IN BETTER AGREEMENT IN TIMING OF THIS FEATURE...IT STILL
LOOKS TO BE RATHER WEAK WITH LIMITED MOISTURE ADVECTION AHEAD OF
IT...AND LITTLE TEMP DIFFERENTIAL ALONG IT. WILL CONTINUE INHERITED
SCHC POP FOR SUNDAY HOWEVER...AND THIS WILL BE THE ONLY REAL PRECIP
CHANCE FOR THE EXTENDED. MID-LEVEL RIDGING QUICKLY REBUILDS BEHIND
THIS BOUNDARY AS IT STALLS AND ERODES JUST SOUTH OF THE CWA
MONDAY...RETURNING DRY AND SEASONABLE CONDITIONS TO THE CAROLINAS.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 00Z...MOST OF THE CONVECTION HAS ENDING...HOWEVER THE FRONT IS
STILL 3-5 HOURS AWAY. THE HRRR MODEL SHOWS A BAND OF MODERATE
SHOWERS OVER THE EASTERN THIRD OF NORTH CAROLINA...PRETTY MUCH ALONG
THE FRONTAL BOUNDARY. ATMOSPHERE HAS BEEN WORKED OVER
MODERATELY...SO THINK ANY FRONTAL CONVECTION WILL BE LIGHT...AND
LAST ONLY AN HOUR OR TWO. BEST CHANCE WILL BE AT ILM WHERE SOME
LEFTOVER INSTABILITY MAY STILL EXIST. WINDS WILL SHIFT TO THE
NORTHEAST...POST FRONTAL. WITH NORTHEAST WINDS EXPECTED AT ALL
TERMINALS AFTER 07Z. WINDS WILL BECOME GUSTY BY DAYBREAK AS MIXING
BEGINS WITH A MODERATE PRESSURE GRADIENT. THE NAM IS ADVERTISING
SOME BRIEF IFR CEILINGS TOWARD MORNING...BUT AM NOT BUYING THIS
SCENARIO AT THIS TIME.
EXTENDED OUTLOOK...EXPECT VFR THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 7 PM MONDAY...A COLD FRONT WILL MOVE ACROSS THE WATERS
OVERNIGHT...SHIFTING WINDS FROM SW TO N AND THEN NE. A NE SURGE
WILL FOLLOW AS COOL AND DRY AIR RUSHES DOWN THE COAST. THIS SURGE
WILL REACH THE NORTHERN WATERS 07-09Z AND THE SOUTHERN WATERS
08-10Z. THE SURGE WILL CONTINUE THROUGH TUE. SUSTAINED NE WINDS WILL
INCREASE TO 15 TO 20 KT OVERNIGHT. SEAS WILL BUILD TO 4 TO 5 FT
TOWARD DAYBREAK AND THEN INCREASE ANOTHER 1 TO 2 FT TUE MORNING.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 230 PM MONDAY...NORTHEAST WINDS WILL BE THE THEME OF THE SHORT
TERM FORECAST AS HIGH PRESSURE SLOWLY MOVES FROM NEW YORK TO
ESSENTIALLY OFF THE DELMARVA. WINS SPEEDS TUESDAY WILL BE 15-20
KNOTS AND VERY SLOWLY WORK DOWN TO 10-15 KNOTS BY THURSDAY AM. I
HAVE RAISED A SMALL CRAFT ADVISORY FOR ALL WATERS FOR TUESDAY WELL
INTO THE EVENING DUE TO SEAS OF SIX FEET. WITH THE DECREASE IN
WINDS...SEAS SHOULD SETTLE DOWN INTO A 2-4 FOOT RANGE LATER
WEDNESDAY.
LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 230 PM MONDAY...RIDGE OF HIGH PRESSURE EXTENDING DOWN THE EAST
COAST WILL GRADUALLY WEAKEN AND MOVE AWAY INTO THE WEEKEND...CAUSING
DECREASING WINDS THROUGH THE PERIOD. INITIALLY...NE WINDS OF 10-15
KTS WILL OCCUR ACROSS THE WATERS...BUT THESE WILL EASE TO LESS THAN
10 KTS FRIDAY AS THE PRESSURE GRADIENT WEAKENS...AND THEN BECOME
LIGHT AND VARIABLE ON SATURDAY AS RETURN FLOW BEGINS TO DEVELOP.
WAVE HEIGHTS WILL RESPOND TO THE EASING WINDS...FALLING FROM 2-4 FT
THURSDAY...TO 1-3 FT FRIDAY AND SATURDAY. A WAVE SHADOWED REGION
WILL EXIST THU/FRI ALONG THE BRUNSWICK COUNTY COAST...WHERE WAVE
HEIGHTS WILL BE ONLY AROUND 1-2 FT NEAR SHORE BOTH DAYS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM TUESDAY TO 2 AM EDT WEDNESDAY
FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...RJD
SHORT TERM...SHK
LONG TERM...JDW
AVIATION...43
AREA FORECAST DISCUSSION
NWS RALEIGH NC
745 PM EDT MON SEP 16 2013
.SYNOPSIS...
A COLD FRONT TO OUR NORTH WILL PUSH SOUTHWARD THROUGH NORTH CAROLINA
THIS EVENING INTO TONIGHT. CANADIAN HIGH PRESSURE WILL BUILD INTO
THE REGION FROM THE NORTH TUESDAY INTO WEDNESDAY.
&&
.NEAR TERM /TONIGHT AND TUESDAY/...
AS OF 300 PM MONDAY...
THROUGH TONIGHT: THE COLD FRONT CURRENTLY SITS ACROSS WV AND CENTRAL
VA... POISED TO CONTINUE DROPPING SOUTHWARD INTO NC BY EARLY THIS
EVENING THEN TO THE SC STATE LINE SOON AFTER MIDNIGHT... PROPELLED
BY THE DIGGING TROUGH OVER THE FAR NORTHEAST STATES. THE DEEPEST
CONVECTION SO FAR THIS AFTERNOON HAS BEEN CONFINED TO AREAS SOUTH
AND EAST OF THE FORECAST AREA WITHIN THE BETTER LOW LEVEL THETA-E
ADVECTION ZONE AND WHERE INSTABILITY HAS BEEN GREATEST (1000 J/KG OF
MLCAPE... MORE THAN THE EARLY MORNING MODELS SUGGESTED). THIS
MORNING`S HIGH DEW POINTS HAVE MIXED OUT WITH HEATING... WELL DOWN
INTO THE 50S TO LOWER 60S OVER ALL BUT THE FAR SE CWA... SO LATEST
HRRR/RAP MODEL TRENDS OF HOLDING THE MORE SIGNIFICANT INSTABILITY
OVER THE FAR SE CWA FOR THE NEXT SEVERAL HOURS APPEARS REASONABLE.
WITH MOISTENING THROUGH THE COLUMN AND INCREASED PW VALUES JUST
AHEAD OF THE FRONT HOWEVER... STILL EXPECT ISOLATED (AND POSSIBLY
SCATTERED) SHOWERS TO PUSH SOUTHWARD INTO NORTH CENTRAL NC THROUGH
THE REST OF THE AFTERNOON... BEFORE PUSHING INTO CENTRAL AND
SOUTHERN SECTIONS OF THE FORECAST AREA BY LATE THIS EVENING. THE
GOOD INVERTED-V SIGNATURE SEEN ON RAP SOUNDINGS SUGGESTS THAT ANY OF
THESE SHOWERS AND STORMS MAY PRODUCE BRIEF STRONG WIND GUSTS.
WIDESPREAD CLOUDS AND A FEW SHOWERS ARE LIKELY TO LINGER INTO THE
OVERNIGHT HOURS OVER THE SW CWA WITH LOW LEVEL FLOW TAKING ON AN
UPSLOPE COMPONENT AND CONTINUED DECENT LOW LEVEL MOISTURE TRANSPORT.
FOLLOWING TRENDS OF THE HRRR AND LOCAL WRF... AND LOOKING AT
UPSTREAM TEMP TRENDS... EXPECT LOWS TO RANGE FROM 57 NORTH TO 64
SOUTH. WINDS BEHIND THE FRONT ARE LIKELY TO STRENGTHEN TO AROUND 10
KTS WITH GUSTS AS MUCH AS 15-20 KTS... ALTHOUGH CONFIDENCE IS LOW
REGARDING HOW MUCH WE`LL STAY MIXED TONIGHT.
FOR TUESDAY: EXPECT IMPROVING CONDITIONS FROM NNE TO SSW AS COOL
HIGH PRESSURE BUILDS IN. THE FRONT IS EXPECTED TO HANG UP ACROSS SC
AND BACK UP INTO FAR SW NC... AND CLOUDS ACROSS OUR FAR SOUTHERN AND
SW AREAS SHOULD BE SLOWER TO CLEAR OUT WITH FORECAST SOUNDINGS
INDICATING LINGERING MOISTURE AT AROUND 850-800 MB... BENEATH THE
WARM SUBSIDING MID LEVELS. OTHERWISE... BESIDES THE CLOUDS... EXPECT
QUIET AND DRY WEATHER WITH NOTABLY COOLER TEMPS... AS THICKNESSES
DROP OVERNIGHT TO AROUND 1370 M... SUPPORTING HIGHS 73-79. -GIH
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 245 PM MONDAY...
A HIGH PRESSURE RIDGE AXIS AT THE SURFACE AND ALOFT WILL EXTEND
ACROSS CENTRAL NC TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. THE DRY
STABLE AIR ASSOCIATED WITH THIS WEATHER FEATURE WILL RESULT IN CLEAR
TO FAIR SKIES AND TEMPS 3-5 DEGREES BELOW NORMAL ON WEDNESDAY. EARLY
WEDNESDAY MORNING LOW TEMPS WILL TEND TO BE A LITTLE CHILLY. MODEL
LOW LEVEL THICKNESSES WEDNESDAY MORNING HOVERING IN THE UPPER 1350S
TO THE MID 1360S. SUNDAY MORNING THICKNESSES VERIFIED IN THE UPPER
1360S. IF MODEL THICKNESSES VERIFY WEDNESDAY MORNING...MIN TEMPS IN
THE 45-50 DEGREE RANGE ONCE AGAIN HIGHLY PROBABLE IN THE OUTLYING
AREAS WITH LOW-MID 50S COMMON IN THE URBAN LOCATIONS. CAVEAT TO MIN
TEMPS WEDNESDAY MORNING: IF DECK OF STRATOCU DEVELOPS BELOW
SUBSIDENCE INVERSION (GFS EMPHASIZES THIS MORE THAN NAM)...THIS
WOULD SUGGEST MIN TEMPS 3-4 DEGREES WARMER THAN
FORECAST...ESPECIALLY ACROSS THE EAST). A MODIFYING AIR MASS BY
WEDNESDAY NIGHT SUGGEST MIN TEMPS 3-5 DEGREES WARMER COMPARED TO
TUESDAY NIGHT. MIN TEMPS GENERALLY IN THE MID-UPPER 50S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 250 PM MONDAY...
THURSDAY THROUGH FRIDAY NIGHT...
AIR MASS WILL UNDERGO MODIFICATION THIS PERIOD AS SURFACE HIGH
PRESSURE RIDGE SLOWLY WEAKENS AND DRIFTS EWD. THIS WILL ESTABLISH A
RETURN FLOW REGIME BY FRIDAY AND CONTINUING INTO FRIDAY NIGHT. WHILE
DRY WEATHER SHOULD RULE THROUGH FRIDAY...A STRAY SHOWER POSSIBLE
OVER THE NW PIEDMONT LATE FRIDAY. THICKNESSES RECOVER THURSDAY INTO
FRIDAY...SUPPORTIVE OF TEMPS RETURNING TO NEAR NORMAL VALUES
(UPPER 70S NW TO LOWER 80S SE).
SATURDAY THROUGH MONDAY...
MEDIUM RANGE MODEL GUIDANCE CONTINUES TO SUGGEST THE NEXT S/W IN THE
NORTHERN STREAM WILL AFFECT CENTRAL NC SATURDAY INTO SUNDAY. 12Z GFS
IS A LITTLE MORE VIGOROUS WITH THE S/W COMPARED TO ITS PREVIOUS RUNS
AS WELL AS THE 00Z ECMWF. GFS DEPICTS DEEPER MOISTURE AND MORE
ORGANIZED LIFT THROUGH THE ATMOSPHERE COMPARED TO THE 00Z ECMWF.
UNLIKE THE PREVIOUS TWO SYSTEMS IN WHICH WLY FLOW AHEAD OF THE FRONT
DETERRED MOISTURE TRANSPORT AND RESULTED IN JUST A FEW
SHOWERS...LATEST GUIDANCE SUGGEST A 12 HOUR WINDOW OF OPPORTUNITY TO
ADVECT MOISTURE OFF THE GULF INTO OUR REGION PRIOR TO FRONTAL
PASSAGE. THUS HAVE INCHED POPS UP A BIT FROM THE PREVIOUS FORECAST
FOR THE PERIOD LATE SATURDAY INTO SATURDAY NIGHT. IF MODEL TRENDS
CONTINUED...HIGH CHANCE OR LIKELY POPS MAY BECOME WARRANTED.
FRONTAL PASSAGE OCCURS SUNDAY INTO SUNDAY NIGHT WITH BETTER RAIN
CHANCES CONFINED TO THE EAST AND SOUTH SUNDAY AFTERNOON COMPARED
TO THE NW. HIGH PRESSURE BUILDS INTO THE REGION MONDAY WITH
ASSOCIATED DRIER AND MORE STABLE AIR MASS.
TEMPS THROUGH THE PERIOD WILL AVERAGE CLOSE TO NORMAL...MAYBE A
LITTLE ABOVE NORMAL SATURDAY ACROSS THE SE HALF AHEAD OF THE
FRONT...AND A COUPLE OF DEGREES BELOW NORMAL AREAWIDE MONDAY.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 745 PM MONDAY...
THE SURFACE COLD FRONT IS CURRENTLY BETWEEN KRDU AND KFAY...AND WILL
PASS KFAY BY 01Z. THERE IS CURRENTLY NO SHOWER ACTIVITY ALONG THE
FRONT...AND THERE IS ONLY A SMALL CHANCE OF ANY SHOWERS DEVELOPING
BEFORE THE FRONT PASSES BY KFAY. BEHIND THE FRONT...MODELS SHOW A
POST FRONTAL SURGE OF NORTHEASTERLY WIND AROUND 10-12KT AS THE
PRESSURE GRADIENT TIGHTENS AND MORE DENSE AIR RUSHES IN FROM THE
NORTH. FORECAST SOUNDINGS ALSO SHOW 20-25KT OF WIND AROUND 2K
FT..WHICH MAY BE ABLE TO PERIODICALLY MIX TO THE SURFACE.
OTHERWISE...CLOUDS WILL LINGER OVERNIGHT BUT CEILINGS ARE EXPECTED
TO REMAIN ABOVE 4K FT.
MORE SIGNIFICANT DRYING WILL OCCUR ON TUESDAY...WITH JUST A SHALLOW
LAYER OF CU EXPECTED FOR MUCH OF THE DAY. THE NAM MODEL CURRENTLY
SHOWS A LAYER OF MOISTURE AROUND 3000-3500 FT MOVING INTO
NORTHEASTERN NC DURING THE AFTERNOON...BUT IS THE ONLY MODEL TO SHOW
THIS AND WOULD PREFER TO SEE THE CLOUD DECK DEVELOP OFF THE DELMARVA
BEFORE ADDING IT TO THE TAF.
OUTLOOK...
PREDOMINATELY VFR CONDITIONS EXPECTED THROUGH THE WORK WEEK...WITH
BETTER CHANCE OF SHOWERS AND STORMS BY NEXT WEEKEND AS A COLD FRONT
MOVES INTO THE REGION. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TH
NEAR TERM...HARTFIELD
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
721 PM EDT MON SEP 16 2013
.SYNOPSIS...
HIGH PRESSURE ACROSS THE GREAT LAKES WILL PUSH A COLD FRONT SOUTH
ACROSS THE CAROLINAS TONIGHT. THE HIGH WILL WEAKEN SLOWLY AS IT
PUSHES OFF THE EAST COAST THURSDAY AND FRIDAY. WARMER AND MORE
HUMID WEATHER IS EXPECTED THIS WEEKEND AHEAD OF ANOTHER COLD FRONT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 7 PM MONDAY...ONGOING CONVECTION WAS EITHER WINDING DOWN OR
MOVING OFFSHORE EARLY THIS EVE. POPS WERE APPROPRIATELY RAISED TO
ACCOUNT FOR THE AREAS WHERE SHOWERS AND A FEW THUNDERSTORMS WILL BE
MOST LIKELY THROUGH THE EARLY EVE. A COLD FRONT WAS JUST BEGINNING
TO MOVE INTO THE NORTHERN REACHES OF THE FORECAST AREA AROUND
PARKTON AND AMMON AND WILL CONTINUE TO SURGE SOUTHWARD...CLEARING
THE AREAS AROUND THE SOUTH SANTEE RIVER PRIOR TO MIDNIGHT. THE UPPER
TROUGH WILL THEN SWEEP ACROSS THE FORECAST AREA OVERNIGHT. ALL OF
THE MODELS ARE CONSISTENT IN SHOWING SIGNIFICANT DRYING WILL NOT
TAKE PLACE UNTIL THE UPPER TROUGH IS OFFSHORE. THUS...HAVE OPTED TO
KEEP SMALL POPS IN THE FORECAST LATE EVE AND OVERNIGHT TO ACCOUNT
FOR THIS. HOWEVER...NO HEAVY RAIN IS EXPECTED ACROSS THE FORECAST
AREA AFTER 9 PM OR SO. HOWEVER...A FLEETING RUMBLE OF THUNDER MAY
STILL OCCUR AFTER MIDNIGHT.
AS THE COOL AND DRY SURGE KICKS IN OVERNIGHT...SUSTAINED NE WINDS
WILL INCREASE TO AROUND 15 MPH WITH HIGHER GUSTS. THIS SURGE WILL
DROP THE DEWPOINTS INTO THE UPPER 50S BY SUNRISE ACROSS THE N...AND
THROUGH THE 60S ELSEWHERE. THE WINDS WILL PROVIDE A WELL MIXED
ENVIRONMENT...AND SO TEMPS WILL NOT FALL OFF SIGNIFICANTLY OVERNIGHT
AND WILL ACTUALLY BE SIMILAR TO THE LOWS THIS MORNING. MID AND UPPER
60S WILL BE COMMON ACROSS THE NORTHERN TWO-THIRDS OF THE AREA WITH
UPPER 60S TO AROUND 70 DEGREES ACROSS THE SOUTHERN THIRD. A TREND
TOWARD CLEARER SKIES WILL HAVE TO WAIT UNTIL TUE.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 230 PM MONDAY...THE MID LEVEL FLOW WILL START OUT WITH A
PROGRESSIVE TROUGH MOVING OFFSHORE WITH THE PATTERN RELAXING
SLIGHTLY THROUGH WEDNESDAY. ANOTHER WEAK SHORTWAVE WILL TURN THE
FLOW TO THE NORTHWEST ONCE AGAIN EARLY THURSDAY. AT THE
SURFACE...HIGH PRESSURE WILL BUILD DOWN FROM THE NORTH/NORTHEAST AND
WITH PRECIPITABLE WATER VALUES FALLING DOWN TO WELL BELOW ONE
INCH...POPS WILL NOT BE AN ISSUE THROUGH THE PERIOD.
THE LATEST NUMERICAL GUIDANCE HAS TRENDED COOLER WITH TEMPERATURES
THROUGH THE PERIOD. I DID GO SLIGHTLY ABOVE THE NUMBERS FOR
WEDNESDAYS LOWS DUE TO THE BOUNDARY LAYER REMAINING MIXED. FOR THIS
REASON THURSDAYS LOWS COULD BE JUST ABOUT THE SAME DUE TO MORE
FAVORABLE RADIATIONAL CONDITIONS DESPITE SOME AIRMASS
MODIFICATION...OTHERWISE I STAYED NEAR GUIDANCE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 230 PM MONDAY...HIGH PRESSURE EXTENDING DOWN THE COAST
COMBINES WITH 5H RIDGING INTO THE WEEKEND TO CREATE SEASONABLE AND
DRY WEATHER ACROSS THE LOCAL AREA. WITH HIGH CENTERED OVER NEW
ENGLAND...SURFACE RIDGE AXIS WILL ONLY GRADUALLY DRIFT EAST...SO
COOL NE FLOW WILL PERSIST THURSDAY BEFORE SLOWLY VEERING AROUND TO
THE SOUTH BY SATURDAY. WHILE THIS VEERING OF WIND WILL CAUSE AIR
MASS MODIFICATION AND WARMING...IT WILL BE SOMEWHAT OFFSET BY
LOWERING MID-LEVEL THICKNESSES IN RESPONSE TO A STRONG POLAR VORTEX
MOVING ACROSS THE GREAT LAKES. THUS...TEMPS WILL RISE FROM JUST
BELOW CLIMO THURSDAY...TO RIGHT AROUND OR SLIGHTLY ABOVE SATURDAY.
COLD FRONT BEING PUSHED SOUTH BY THE AFOREMENTIONED VORTEX WILL MOVE
TOWARDS THE AREA SUNDAY...CROSSING SOUTH BY SUNDAY NIGHT. WHILE
GUIDANCE IS IN BETTER AGREEMENT IN TIMING OF THIS FEATURE...IT STILL
LOOKS TO BE RATHER WEAK WITH LIMITED MOISTURE ADVECTION AHEAD OF
IT...AND LITTLE TEMP DIFFERENTIAL ALONG IT. WILL CONTINUE INHERITED
SCHC POP FOR SUNDAY HOWEVER...AND THIS WILL BE THE ONLY REAL PRECIP
CHANCE FOR THE EXTENDED. MID-LEVEL RIDGING QUICKLY REBUILDS BEHIND
THIS BOUNDARY AS IT STALLS AND ERODES JUST SOUTH OF THE CWA
MONDAY...RETURNING DRY AND SEASONABLE CONDITIONS TO THE CAROLINAS.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 00Z...MOST OF THE CONVECTION HAS ENDING...HOWEVER THE FRONT IS
STILL 3-5 HOURS AWAY. THE HRRR MODEL SHOWS A BAND OF MODERATE
SHOWERS OVER THE EASTERN THIRD OF NORTH CAROLINA...PRETTY MUCH ALONG
THE FRONTAL BOUNDARY. ATMOSPHERE HAS BEEN WORKED OVER
MODERATELY...SO THINK ANY FRONTAL CONVECTION WILL BE LIGHT...AND
LAST ONLY AN HOUR OR TWO. BEST CHANCE WILL BE AT ILM WHERE SOME
LEFTOVER INSTABILITY MAY STILL EXIST. WINDS WILL SHIFT TO THE
NORTHEAST...POST FRONTAL. WITH NORTHEAST WINDS EXPECTED AT ALL
TERMINALS AFTER 07Z. WINDS WILL BECOME GUSTY BY DAYBREAK AS MIXING
BEGINS WITH A MODERATE PRESSURE GRADIENT. THE NAM IS ADVERTISING
SOME BRIEF IFR CEILINGS TOWARD MORNING...BUT AM NOT BUYING THIS
SCENARIO AT THIS TIME.
EXTENDED OUTLOOK...EXPECT VFR THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 7 PM MONDAY...A COLD FRONT WILL MOVE ACROSS THE WATERS
OVERNIGHT...SHIFTING WINDS FROM SW TO N AND THEN NE. A NE SURGE
WILL FOLLOW AS COOL AND DRY AIR RUSHES DOWN THE COAST. THIS SURGE
WILL REACH THE NORTHERN WATERS 07-09Z AND THE SOUTHERN WATERS
08-10Z. THE SURGE WILL CONTINUE THROUGH TUE. SUSTAINED NE WINDS WILL
INCREASE TO 15 TO 20 KT OVERNIGHT. SEAS WILL BUILD TO 4 TO 5 FT
TOWARD DAYBREAK AND THEN INCREASE ANOTHER 1 TO 2 FT TUE MORNING.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 230 PM MONDAY...NORTHEAST WINDS WILL BE THE THEME OF THE SHORT
TERM FORECAST AS HIGH PRESSURE SLOWLY MOVES FROM NEW YORK TO
ESSENTIALLY OFF THE DELMARVA. WINS SPEEDS TUESDAY WILL BE 15-20
KNOTS AND VERY SLOWLY WORK DOWN TO 10-15 KNOTS BY THURSDAY AM. I
HAVE RAISED A SMALL CRAFT ADVISORY FOR ALL WATERS FOR TUESDAY WELL
INTO THE EVENING DUE TO SEAS OF SIX FEET. WITH THE DECREASE IN
WINDS...SEAS SHOULD SETTLE DOWN INTO A 2-4 FOOT RANGE LATER
WEDNESDAY.
LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 230 PM MONDAY...RIDGE OF HIGH PRESSURE EXTENDING DOWN THE EAST
COAST WILL GRADUALLY WEAKEN AND MOVE AWAY INTO THE WEEKEND...CAUSING
DECREASING WINDS THROUGH THE PERIOD. INITIALLY...NE WINDS OF 10-15
KTS WILL OCCUR ACROSS THE WATERS...BUT THESE WILL EASE TO LESS THAN
10 KTS FRIDAY AS THE PRESSURE GRADIENT WEAKENS...AND THEN BECOME
LIGHT AND VARIABLE ON SATURDAY AS RETURN FLOW BEGINS TO DEVELOP.
WAVE HEIGHTS WILL RESPOND TO THE EASING WINDS...FALLING FROM 2-4 FT
THURSDAY...TO 1-3 FT FRIDAY AND SATURDAY. A WAVE SHADOWED REGION
WILL EXIST THU/FRI ALONG THE BRUNSWICK COUNTY COAST...WHERE WAVE
HEIGHTS WILL BE ONLY AROUND 1-2 FT NEAR SHORE BOTH DAYS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 AM TUESDAY TO 2 AM EDT WEDNESDAY
FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...RJD
SHORT TERM...SHK
LONG TERM...JDW
AVIATION...43
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
641 PM CDT MON SEP 16 2013
.UPDATE...
ISSUED AT 640 PM CDT MON SEP 16 2013
WE WILL INCREASE WINDS A BIT TONIGHT INTO TUE...WITH A TIGHT
PRESSURE GRADIENT AND ABOUT 40KT TO MIX LATER TONIGHT AND TUE.
TEMPS TONIGHT COULD FALL MORE IN THE EAST...SO WILL KEEP AN EYE ON
DECOUPLING THERE. WILL KEEP SOME INCREASING CLOUDS LATER
TONIGHT...BUT THE LATEST HRRR INDICATES THIS CLOUD INCREASE MAY
OCCUR TUE MORNING...SO SOMETHING WE WILL CONTINUE TO MONITOR
TONIGHT. OTHERWISE...NO OTHER CHANGES PLANNED FOR THIS UPDATE.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 320 PM CDT MON SEP 16 2013
FORECAST CHALLENGES ABOUND IN THE SHORT TERM...THE POSSIBILITY FOR
LOW CLOUDS LATE TONIGHT/EARLY TUE...WIND POTENTIAL TUE PLUS PCPN
CHANCES WED NIGHT INTO THU. PRETTY MUCH FOLLOWED A MODEL BLEND FOR
THIS PORTION OF THE FORECAST. AS FOR TONIGHT THE GUSTS IN THE
SOUTH WINDS SHOULD ABATE AFTER DARK BUT 925MB WINDS WILL REMAIN
AT 30-40KTS. SHOULD HAVE MOSTLY CLEAR SKIES AND STEADY SOUTH WINDS
WHICH WILL HOLD ANY FOG AT BAY. VISIBLE SATELLITE IMAGERY SHOWS
EXTENSIVE LOW CLOUDS ACROSS SOUTHERN SD INTO NE/IA. WITH THE SOUTH
WINDS TONIGHT SOME OF THESE MAY PUSH UP INTO THE FA LATE. IF THESE
LOW CLOUDS MAKE IT INTO THE FA LATE TONIGHT/EARLY TUE AND HOLD
TOGETHER THRU THE DAY THEY WILL HAVE AN IMPACT ON HIGH TEMPS.
UNDERCUT MODEL GUIDANCE HIGHS ON TUE FOR THIS REASON. ALTHOUGH
925MB WINDS DECREASE THRU THE DAY TUE THERE IS STILL ENOUGH TO
PROVIDE FOR WINDY CONDITIONS. DO NOT THINK THERE IS QUITE ENOUGH
FOR A WIND ADVISORY BUT IT WILL DEFINITELY BE A WINDY DAY. LOW
CLOUDS MAY STILL LINGER IN THE EASTERN FA TUE NIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 320 PM CDT MON SEP 16 2013
SFC LOW PRESSURE EXPECTED TO MOVE INTO CENTRAL ND BY 00Z THU.
MODELS ARE SHOWING ABOUT 10C AT 700MB AHEAD OF THE LOW WHICH IS
PRETTY WARM FOR MID SEPT. AS A RESULT MODELS ARE SHOWING LESS PCPN
POTENTIAL IN THE WARM SECTOR WHICH INCLUDES MOST OF THE FA ON WED.
LEFT SOME LOW PCPN CHANCES AROUND THE KDVL REGION WHICH IS CLOSER
TO THE SFC FRONT/LOW. WITH THE EXCEPTION OF THE NAM THE OTHER
MODELS ARE ALSO SHOWING LESS PCPN POTENTIAL ACROSS THE SOUTH INTO
WED NIGHT. BY THU MORNING A DRY SLOT WILL ALSO BE POISED TO MOVE
INTO THE FA. THIS DRY SLOT SHOULD KEEP MOST OF THE FA DRY INTO
THU.
FOR THU NIGHT THROUGH MONDAY...AS SHORTWAVE AND CANADIAN SURFACE
LOW PROPAGATES EAST THURSDAY NIGHT ANY PCPN CHANCES SHOULD BE
LIMITED TO FAR NORTH WITH SOME WRAP-AROUND PCPN. REGION WILL BE IN
SHARP CYCLONIC FLOW AND WITH COLD POOL CANNOT RULE OUT SHRA MAINLY
ACROSS N MN FRIDAY. HIGH PRESSURE WILL BUILD INTO FA SAT BUT WILL
REMAIN COOL. SUNDAY WILL SEE INCREASING RETURN FLOW AND ROBUST
WARM ADVECTION AHEAD OF NEXT SIGNIFICANT MID LEVEL WAVE.
TEMPERATURES LIKELY TO RANGE ABOVE AVERAGE WITH PCPN CHANCES
INCREASING LATE SUNDAY NIGHT/MONDAY AS COLD FRONT APPROACHES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 640 PM CDT MON SEP 16 2013
EXPECT VFR CONDITIONS AND WINDS GUSTING TO AROUND 25KT ON TUE.
THERE COULD BE SOME INCREASING LOWER CLOUDS LATER TONIGHT AND TUE
MORNING...ESPECIALLY IN THE EAST AND SOUTH. FOR NOW WILL NOT
INCLUDE THESE CLOUDS WITH CONFIDENCE LOW...BUT CONTINUE TO
MONITOR.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...DK
SHORT TERM...GODON
LONG TERM...GODON/VOELKER
AVIATION...DK
AREA FORECAST DISCUSSION
NWS PORTLAND OR
223 AM PDT SUN SEP 15 2013
.SYNOPSIS...A TROUGH OF LOW PRESSURE WILL MOVE OVER THE PACIFIC NW
TODAY THROUGH TUESDAY...RESULTING IN COOLER AND SHOWERY WEATHER.
THERE MAY BE SOME ISOLATED THUNDERSTORMS EMBEDDED WITHIN THE SHOWERS
TODAY. THE TROUGH WILL DEPART WEDNESDAY AND AN UPPER RIDGE WILL BRING
DRY AND WARMER WEATHER FOR THURSDAY. ANOTHER TROUGH WILL BRING A
RETURN OF RAIN AND COOLER TEMPERATURES FRIDAY.
&&
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT...THE PORTLAND FORECAST
AREA IS STILL UNDER A STRONG INVERSION EARLY THIS MORNING WITH THE
UPPER LOW STILL OFFSHORE. LOW CLOUDS AND FOG HAS FILLED IN ALONG THE
COAST OVERNIGHT AND STRATUS IS PUSHING INLAND THIS MORNING. THE LOW
CLOUDS ARE FILLING IN FASTER FROM THE SOUTH TO THE NORTH...BUT SHOULD
COVER MOST OF THE WILLAMETTE VALLEY BY SUNRISE.
THE LOW IS NEARING THE OREGON COAST AND WATER VAPOR IMAGERY SHOWS A
BAND OF MID/UPPER LEVEL MOISTURE JUST OFFSHORE SOUTHERN OREGON.
MOISTURE CIRCULATING AROUND THE INLAND HIGH IS ALSO STREAMING OVER
EXTREME NW OREGON AND SW WASHINGTON AND BE ME AN INDICATION OF WHERE
THE GREATEST POTENTIAL FOR THUNDERSTORMS WILL BE TODAY.
FORECASTING THUNDERSTORM/SHOWER CHANCES AND LOCATION ARE THE GREATEST
SHORT-TERM CHALLENGES THIS MORNING. THERE WAS A LIGHTNING STRIKE NEAR
THE LOW CENTER OVERNIGHT INDICATIVE OF SOME ELEVATED
INSTABILITY...BUT WOULD LIKE TO SEE MORE CONVECTION OFFSHORE BEFORE
INCREASING PROBABILITIES FOR THE PORTLAND FORECAST AREA.
BESIDES SOME DRIZZLE ALONG THE COAST THINK MOST AREAS WILL BE MORE ON
THE DRY SIDE THIS MORNING AND HAVE REDUCED POPS. HAVE ALSO REMOVED
THUNDERSTORMS FOR THE EARLY MORNING AS THE BEST DYNAMICS AND CHANCES
LOOK TO BE THIS AFTERNOON AS THE TROUGH BEGINS TO SHIFT OVER THE
AREA. THE HRRR MODEL WHICH HAS BEEN PERFORMING EXCEPTIONALLY WELL IN
REGARDS TO CONVECTION THIS SEASON SUGGESTS THAT THE BEST CHANCES FOR
SOME ELEVATED SHOWERS AND EMBEDDED THUNDERSTORMS IS DURING THE MID TO
LATE MORNING THROUGH THE AFTERNOON ALONG A BROAD AND NOT
SUPER-REFINED AXIS FROM ASTORIA SOUTH AND EAST TO MT JEFFERSON. THIS
IS WHERE WE ARE IN THE RIGHT ENTRANCE OF THE UPPER JET...HAVE GOOD
DIFFLUENCE ALOFT...AND HAVE IMPRESSIVE MID LEVEL
LAPSE RATES. BE AWARE THAT IF YOU HEAR THUNDER IT MAY CATCH YOU OFF
GUARD AS IT MAY BE WELL ABOVE THE STRATUS DECK.
IN THE AFTERNOON PERIOD...SURFACE/LOWER BASED INSTABILITY INCREASES
IN THE CASCADES AND IS BETTER CO-LOCATED WITH THE DYNAMICS ASSOCIATED
WITH THE TROUGH AXIS/TROPOPAUSE FOLD AS THE UPPER TROUGH SHIFTS
NORTH. SO AT THIS TIME ELEVATED SHOWERS AND EMBEDDED THUNDERSTORMS
LOOK TO REMAIN POSSIBLE ALONG THE NORTHERN TIER OF THE AREA...WITH
ADDITIONAL SHOWERS AND THUNDERSTORMS FORMING ALONG THE CASCADES AND
EAST OF THE CWA INTO CENTRAL OREGON IN PLACES THAT GET SOME HEATING.
OTHERWISE COOLER TEMPERATURES CAN BE EXPECTED TODAY AND CONTINUING
THROUGH TUESDAY AS THE UPPER TROUGH LINGERS OVER THE AREA.A WEAK
COLD FRONT WILL MOVE ACROSS THE AREA LATE TONIGHT AND MONDAY AND
CONTINUE THE CHANCES FOR RAIN. THERE MAY BE A BRIEF BREAK IN THE RAIN
MONDAY NIGHT BEFORE A SHORTWAVE TROUGH BRINGS ADDITIONAL SHOWERS TO
THE AREA TUESDAY. THE TROUGH AXIS SHOULD PUSH EAST OF THE AREA
TUESDAY NIGHT.
.LONG TERM...WEDNESDAY THROUGH SATURDAY NIGHT...AN UPPER RIDGE WILL
BUILD WEDNESDAY BEHIND THE DEPARTING TROUGH. THE RIDGE WILL AMPLIFY
THURSDAY AS ANOTHER UPPER LEVEL LOW DEVELOPS OFFSHORE...RESULTING IN
DRY AND WARMER CONDITIONS. MODELS ARE IN FAIRLY GOOD AGREEMENT THAT
THE LOW WILL SWING A COLD FRONT THROUGH THE REGION FRIDAY. THIS LOW
WILL LINGER OVER THE AREA SATURDAY...FOR SLIGHTLY BELOW NORMAL
TEMPERATURES AND A CONTINUING CHANCE FOR RAIN. TH/BURGESS
&&
.AVIATION...LOW LEVEL WINDS ALONG THE COAST HAVE TURNED TO THE SW
THIS MORNING AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. THIS IS
RESULTING IN IFR OR LOWER CONDITIONS FOR THE COASTAL TAF
SITES IN LOW STRATUS...FOG...AND PATCHY DRIZZLE. A SOUTHERLY SURGE
OF MARINE MOISTURE IS ALSO PUSHING INLAND UP THE WILLAMETTE
VALLEY. CURRENT SATELLITE IMAGERY SHOWS THE STRATUS UP INTO THE
CENTRAL VALLEY AND EXPECT IT TO CONTINUE NORTH INTO THE PORTLAND
METRO AREA IN THE NEXT COUPLE OF HOURS. SOME ELEVATED SHOWER OR
THUNDERSHOWER ACTIVITY IS POSSIBLE TODAY...ESPECIALLY BETWEEN 15Z AND
21Z. CIGS MAY LIFT A BIT THIS AFTERNOON...BUT EXPECT MVFR
CONDITIONS INLAND AND IFR AT THE COAST TO PERSIST THROUGH MOST OF
THE DAY. THERE MAY BE SOME BRIEF PERIODS OF VFR WITH ANY SHOWER
ACTIVITY DUE TO MIXING OF THE LOW LEVEL AIR MASS. CIGS WILL LOWER
AGAIN THIS EVENING AS SW LOW LEVEL FLOW CONTINUES.
KPDX AND APPROACHES...VFR CONDITIONS SHOULD GIVE WAY TO MVFR
STRATUS AROUND 11Z TO 12Z THIS MORNING. THERE IS A 30 TO 50 PERCENT
CHANCE A THUNDERSTORM WILL IMPACT THE TERMINAL BETWEEN 15Z AND 21Z
SUNDAY. CIGS MAY LIFT A BIT THIS AFTERNOON...BUT MOSTLY MVFR
CONDITIONS TO PERSIST THROUGH TODAY. CIGS WILL LOWER AGAIN THIS
EVENING. PYLE
&&
.MARINE...FLOW WILL TURN SW THIS MORNING OVER THE WATERS AS A LOW
PRESSURE SYSTEM APPROACHES THE COAST. THIS LOW WILL BRING THE
CHANCE FOR SOME SCATTERED THUNDERSTORM ACTIVITY TODAY. OTHERWISE
EXPECT LITTLE IMPACT FROM THE SYSTEM. CONDITIONS SHOULD REMAIN
RATHER BENIGN FOR THE NEXT SEVERAL DAYS...WITH WINDS GENERALLY
BELOW 20 KT AND SEAS BELOW 6 FT.
ANOTHER WEAK SYSTEM WILL ARRIVE ON TUE...WITH LITTLE IMPACT OTHER
THAN AGAIN TURNING THE WINDS BRIEFLY TO THE SW. THE NEXT
POTENTIALLY SIGNIFICANT MARINE IMPACTS LOOK TO ARRIVE LATE NEXT
WEEK INTO NEXT WEEKEND. A MORE ACTIVE WEATHER PATTERN WILL
ARRIVE AS A SHARP UPPER LEVEL TROUGH APPROACHES THE PAC NW. SMALL
CRAFT ADVISORIES WILL LIKELY BE NECESSARY WITH A CHANCE FOR GALES
AND SEAS OVER 10 FT AT SOME POINT. CONFIDENCE ON TIMING REMAINS
LOW THIS FAR OUT...BUT CONFIDENCE IS INCREASING ON THE OVERALL
PATTERN. PYLE
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
REST OF THE FORECAST DISCUSSION UNCHANGED...ONSHORE WINDS AND STRONG
COOLING ALOFT WILL BRING COOLER TEMPS BEGINNING SUN AND CONTINUING
THROUGH TUE. UPPER TROUGH EXPECTED TO LINGER OVER THE REGION SUN
NIGHT THROUGH TUE...SO IT WILL BE DIFFICULT TO RULE OUT ANY PERIODS
FROM THE THREAT OF SHOWERS. A WEAK SHORTWAVE LATE SUN NIGHT AND MON
MORNING PROVIDES A BIT BETTER OF A CHANCE FOR SHOWERS...THEN A
STRONGER SHORTWAVE TUE WILL BRING BACK BETTER CHANCES FOR SHOWERS.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY...UPPER TROUGH MOVES
EAST OF THE AREA LATE TUESDAY INTO EARLY WEDNESDAY...WITH UPPER
RIDGING BUILDING IN WEDNESDAY EVENING. THE UPPER RIDGE AMPLIFIES
OVER THE PACNW ON THURSDAY IN RESPONSE TO A DEVELOPING LOW AND
ASSOCIATED TROUGH OFFSHORE. MODELS ARE IN FAIRLY GOOD AGREEMENT THAT
THURSDAY WILL BE SUNNY AND WARM...BEFORE THE AFOREMENTIONED LOW
SWINGS A COOL FRONT THROUGH THE REGION FRIDAY. THIS LOW WILL LINGER
OVER THE AREA SATURDAY...FOR SLIGHTLY BELOW NORMAL TEMPERATURES AND
A CONTINUING CHANCE FOR RAIN. BURGESS
&&
.AVIATION...A MIX OF IFR AND MVFR CONDITIONS ALONG THE COAST WILL
LIKELY CONTINUE THROUGH SUNDAY. IFR TO MVFR CONDITIONS CURRENTLY
ACROSS THE SOUTHERN HALF OF THE WILLAMETTE VALLEY WILL TURN VFR
SHORTLY.A STRONG SOUTHWEST PUSH LATE TONIGHT SHOULD ALLOW MVFR CIGS
TO SPREAD NORTHWARD UP THE WILLAMETTE VALLEY BETWEEN 06Z AND 15Z
SUNDAY. ELEVATED THUNDER BECOMES POSSIBLE AS EARLY AS 09Z AND WILL
FORM WELL ABOVE THE STRATUS LAYER. HOWEVER...BETTER CHANCES WILL BE
AS THE UPPER LEVEL WAVE SLIDES NORTH ALONG THE COAST. DON`T HAVE
ENOUGH CONFIDENCE TO SPECIFICALLY INCLUDE FOR KONP KEUG KSLE AND
KAST YET BUT IT SEEMS LIKE EVERYTHING IS COMING TOGETHER FOR THE
KPDX KTTD AND KHIO AREA BEGINNING AROUND 17Z. EXPECT THE PRIMARY
THUNDER THREAT WILL LAST A FEW HOURS BEFORE EVOLVING INTO SCATTERED
SHOWER ACTIVITY. MAIN CHALLENGE WILL BE IF THERE IS STRATUS ACROSS
THE NORTH WITH THE THUNDER ABOVE OR IF THE STRATUS WILL BE RAPIDLY
MIXED OUT UNDER THE LEADING EDGE OF SHOWER ACTIVITY EARLIER. NAM AND
GFS DIFFER ON THIS AND PRELIMINARILY DECIDED TO FOLLOW THE GFS FOR
THE 06Z PACKAGE.
KPDX AND APPROACHES...VFR CONDITIONS SHOULD GIVE WAY TO MVFR
CONDITIONS AROUND 12Z SUNDAY...WHICH WILL LIKELY PERSIST WELL INTO
SUNDAY. THERE IS A 30 TO 50 PERCENT CHANCE A THUNDERSTORM WILL
IMPACT THE TERMINAL BETWEEN 15Z AND 21Z SUNDAY. JBONK/NEUMAN
&&
.MARINE...ONLY CHANGE WAS TO NUDGE UP THE WIND WAVES AND SWELL BY
ABOUT A FOOT. THIS BETTER MATCHES OBS NOW AND IS CLOSER TO ENP
FORECASTS FOR THE NEXT 18 HOURS. PREVIOUS DISCUSSION FOLLOWS. /JBONK
BENIGN CONDITIONS TO REMAIN OVER THE WATERS INTO EARLY NEXT WEEK.
WINDS SHOULD REMAIN GENERALLY BELOW 20 KT...WITH SEAS BELOW 6 FT.
THERE WILL BE A CHANCE FOR THUNDERSTORMS OVER THE WATERS LATE
TONIGHT AND SUNDAY AS AN UPPER LEVEL SYSTEM PASSES OVERHEAD.
A MORE ACTIVE WEATHER PATTERN WILL ARRIVE LATE NEXT
WEEK...SPECIFICALLY THURSDAY THROUGH SATURDAY. SMALL CRAFT ADVISORIES
WILL LIKELY BE NECESSARY WITH A CHANCE FOR GALES AND SEAS OVER 10 FT
AT SOME POINT DEPENDING UPON THE TRACK OF DEVELOPING LOW PRESSURES.
HOWEVER...MODELS HAVE VARIED WIDELY FROM RUN TO RUN...AND GIVEN THE
TIME OF YEAR...KEPT WINDS AND SEAS AT MORE MODEST LEVELS. /NEUMAN
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1057 PM EDT MON SEP 16 2013
.SYNOPSIS...
HIGH PRESSURE WILL DOMINATE THE WEATHER PATTERN THROUGH THE MIDDLE
OF THE WEEK. AFTER A CHILLY START ON TUESDAY...A MILDER SOUTHWEST
FLOW WILL DEVELOP THROUGH THE SECOND HALF OF THE WEEK...WITH
TEMPERATURES CLIMBING SLIGHTLY ABOVE NORMAL. A COLD FRONT WILL
BRING SHOWERY CONDITIONS AS IT CROSSES THE REGION OVER THE
WEEKEND...FOLLOWED BY ANOTHER COOL CANADIAN AIR MASS FOR EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SKIES CONTINUING TO CLEAR AS SPRAWLING HIGH PRES BUILDS SEWD ACRS
THE LWR LKS. THIS WILL BRING A CHILLY NIGHT TO THE REGION...WITH
TEMPS SLIPPING BACK INTO THE 30S AND 40S. A FROST ADVISORY HAS
BEEN POSTED FOR THE NORTHERN TIER.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL MAINTAIN ITS GRIP ON THE REGION THRU WEDNESDAY
BEFORE SLOWLY RETREATING OFF THE SRN NEW ENGLAND COAST THURSDAY
NIGHT. A MILDER RETURN S-SW FLOW WILL BRING ABOUT A SLOW
MODERATION IN DAILY MAX/MIN TEMPS WITH A GRADUAL INCREASE IN
HUMIDITY. TOMORROW NIGHT WILL AGAIN BE CHILLY ACROSS THE NRN TIER
WITH PATCHY FROST POSSIBLE...WITH IS HIGHLIGHTED IN THE HWO.
SCT CONVECTION IS POSSIBLE OVER THE WRN AND CNTRL ZONES THU
AFTN INTO THU NGT...AS WARM FRONT BEGINS TO LIFT NEWD FROM THE
UPPER OH VLY INTO WRN PA.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
TEMPERATURES SHOULD PEAK ON FRIDAY AS THE AREA BREAKS INTO THE WARM
SECTOR AHEAD OF A WELL-DEFINED COLD FRONT PUSHING EWD THRU THE GRT
LKS/OH VLY. THERE ARE SOME MINOR TIMING DIFFS CONCERNING THE COLD
FROPA ON SATURDAY...WITH THE GFS/GEFS A LITTLE MORE PROGRESSIVE
THAN THE ECMWF. DECENT SURGE OF MSTR WITH ABV NORMAL PWATS AHEAD
OF THE FRONT SHOULD PROMOTE SCT CONVECTIVE RAINS ON DAY 5 AND 6.
SOME SHOWER ACTIVITY MAY LINGER INTO SUNDAY WITH THE UPPER TROUGH
PASSAGE...BEFORE HIGH PRESSURE BRINGS A COOLING TREND WITH DRY WX
FROM LATE IN THE WEEKEND INTO EARLY NEXT WEEK.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
LOW LVL MOISTURE TRAPPED BENEATH INVERSION IS RESULTING IN A
STRATOCU DECK WITH LOW CIGS ALONG THE PA/NY BORDER EARLY THIS
EVENING. CONCERN IS THAT SOME OF THESE LOW CIGS WILL CREEP INTO
BFD EARLY THIS EVENING BEFORE MUCH DRIER AIR ARRIVES LATE THIS
EVENING. THE LEADING EDGE OF THIS DRIER AIR MASS IS EVIDENT BY
RAPID CLEARING TAKING PLACE ALONG THE SOUTH SHORE OF LK ONTARIO AT
23Z. BASED ON UPSTREAM OBS...CAN NOT RULE OUT A PERIOD OF IFR
CIGS AT BFD BTWN 00Z-02Z. HOWEVER...MVFR CIGS SEEM MORE LIKELY DUE
TO A BIT OF DOWNSLOPING WITH NORTHERLY WIND. RAP MDL SOUNDINGS
SHOW THE MUCH DRIER AIR ARRIVING BTWN 02Z-03Z...AFTER WHICH MAINLY
CLEAR SKIES EXPECTED ACROSS ALL OF CENTRAL PA.
DIMINISHING WINDS...COOL TEMPS AND RELATIVELY WARM RIVER/STREAM
WATER...SHOULD RESULT IN PATCHY FOG IN THE DEEP VALLEYS OF THE
ALLEGHENIES EARLY TUE AM. CLIMATOLOGY WOULD INDICATE BFD AND IPT
COULD SEE A BRIEF VIS/CIG REDUCTION ARND DAWN.
LARGE HIGH PRESSURE SYSTEM AND ASSOCIATED DRY AIR MASS WILL BE OVR
THE REGION LATER TUESDAY...RESULTING IN A NEAR CERTAINTY OF
MSUNNY SKIES AND LIGHT WINDS.
OUTLOOK...
WED...PATCHY AM FOG POSSIBLE.
THU...PATCHY AM FOG POSS EAST. ISOLD PM TSRA IMPACTS POSS W MTNS.
FRI...ISOLD PM TSRA IMPACTS POSSIBLE W MTNS.
SAT...SCT...MAINLY PM...TSRA IMPACTS POSS WITH FROPA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 2 AM TO 8 AM EDT TUESDAY FOR PAZ004>006-
037-041-042.
&&
$$
SYNOPSIS...RXR
NEAR TERM...DEVOIR/RXR
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
742 PM EDT MON SEP 16 2013
.SYNOPSIS...
HIGH PRESSURE WILL DOMINATE THE WEATHER PATTERN THROUGH THE MIDDLE
OF THE WEEK. AFTER A CHILLY START ON TUESDAY...A MILDER SOUTHWEST
FLOW WILL DEVELOP THROUGH THE SECOND HALF OF THE WEEK...WITH
TEMPERATURES CLIMBING SLIGHTLY ABOVE NORMAL. A COLD FRONT WILL
BRING SHOWERY CONDITIONS AS IT CROSSES THE REGION OVER THE
WEEKEND...FOLLOWED BY ANOTHER COOL CANADIAN AIR MASS FOR EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
INSTABILITY SHOWERS HAVE WANED EXCEPT FOR ONE WHICH WILL DIE IN
THE NEXT 30 MINUTES OVER CUMBERLAND COUNTY. SKIES WILL CLEAR
DURING MID TO LATE EVENING AS SPRAWLING HIGH PRES BUILDS SEWD
ACRS THE LWR LKS. THIS WILL BRING A CHILLY NIGHT TO THE
REGION...WITH TEMPS SLIPPING BACK INTO THE 30S AND 40S. A FROST
ADVISORY HAS BEEN POSTED FOR THE NORTHERN TIER.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL MAINTAIN ITS GRIP ON THE REGION THRU WEDNESDAY
BEFORE SLOWLY RETREATING OFF THE SRN NEW ENGLAND COAST THURSDAY
NIGHT. A MILDER RETURN S-SW FLOW WILL BRING ABOUT A SLOW
MODERATION IN DAILY MAX/MIN TEMPS WITH A GRADUAL INCREASE IN
HUMIDITY. TOMORROW NIGHT WILL AGAIN BE CHILLY ACROSS THE NRN TIER
WITH PATCHY FROST POSSIBLE...WITH IS HIGHLIGHTED IN THE HWO.
SCT CONVECTION IS POSSIBLE OVER THE WRN AND CNTRL ZONES THU
AFTN INTO THU NGT...AS WARM FRONT BEGINS TO LIFT NEWD FROM THE
UPPER OH VLY INTO WRN PA.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
TEMPERATURES SHOULD PEAK ON FRIDAY AS THE AREA BREAKS INTO THE WARM
SECTOR AHEAD OF A WELL-DEFINED COLD FRONT PUSHING EWD THRU THE GRT
LKS/OH VLY. THERE ARE SOME MINOR TIMING DIFFS CONCERNING THE COLD
FROPA ON SATURDAY...WITH THE GFS/GEFS A LITTLE MORE PROGRESSIVE
THAN THE ECMWF. DECENT SURGE OF MSTR WITH ABV NORMAL PWATS AHEAD
OF THE FRONT SHOULD PROMOTE SCT CONVECTIVE RAINS ON DAY 5 AND 6.
SOME SHOWER ACTIVITY MAY LINGER INTO SUNDAY WITH THE UPPER TROUGH
PASSAGE...BEFORE HIGH PRESSURE BRINGS A COOLING TREND WITH DRY WX
FROM LATE IN THE WEEKEND INTO EARLY NEXT WEEK.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
LOW LVL MOISTURE TRAPPED BENEATH INVERSION IS RESULTING IN A
STRATOCU DECK WITH LOW CIGS ALONG THE PA/NY BORDER EARLY THIS
EVENING. CONCERN IS THAT SOME OF THESE LOW CIGS WILL CREEP INTO
BFD EARLY THIS EVENING BEFORE MUCH DRIER AIR ARRIVES LATE THIS
EVENING. THE LEADING EDGE OF THIS DRIER AIR MASS IS EVIDENT BY
RAPID CLEARING TAKING PLACE ALONG THE SOUTH SHORE OF LK ONTARIO AT
23Z. BASED ON UPSTREAM OBS...CAN NOT RULE OUT A PERIOD OF IFR
CIGS AT BFD BTWN 00Z-02Z. HOWEVER...MVFR CIGS SEEM MORE LIKELY DUE
TO A BIT OF DOWNSLOPING WITH NORTHERLY WIND. RAP MDL SOUNDINGS
SHOW THE MUCH DRIER AIR ARRIVING BTWN 02Z-03Z...AFTER WHICH MAINLY
CLEAR SKIES EXPECTED ACROSS ALL OF CENTRAL PA.
DIMINISHING WINDS...COOL TEMPS AND RELATIVELY WARM RIVER/STREAM
WATER...SHOULD RESULT IN PATCHY FOG IN THE DEEP VALLEYS OF THE
ALLEGHENIES EARLY TUE AM. CLIMATOLOGY WOULD INDICATE BFD AND IPT
COULD SEE A BRIEF VIS/CIG REDUCTION ARND DAWN.
LARGE HIGH PRESSURE SYSTEM AND ASSOCIATED DRY AIR MASS WILL BE OVR
THE REGION LATER TUESDAY...RESULTING IN A NEAR CERTAINTY OF
MSUNNY SKIES AND LIGHT WINDS.
OUTLOOK...
WED...PATCHY AM FOG POSSIBLE.
THU...PATCHY AM FOG POSS EAST. ISOLD PM TSRA IMPACTS POSS W MTNS.
FRI...ISOLD PM TSRA IMPACTS POSSIBLE W MTNS.
SAT...SCT...MAINLY PM...TSRA IMPACTS POSS WITH FROPA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 2 AM TO 8 AM EDT TUESDAY FOR PAZ004>006-
037-041-042.
&&
$$
SYNOPSIS...RXR
NEAR TERM...DEVOIR/RXR
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
740 PM EDT MON SEP 16 2013
.SYNOPSIS...
HIGH PRESSURE WILL DOMINATE THE WEATHER PATTERN THROUGH THE MIDDLE
OF THE WEEK. AFTER A CHILLY START ON TUESDAY...A MILDER SOUTHWEST
FLOW WILL DEVELOP THROUGH THE SECOND HALF OF THE WEEK...WITH
TEMPERATURES CLIMBING SLIGHTLY ABOVE NORMAL. A COLD FRONT WILL
BRING SHOWERY CONDITIONS AS IT CROSSES THE REGION OVER THE
WEEKEND...FOLLOWED BY ANOTHER COOL CANADIAN AIR MASS FOR EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
INSTABILITY SHOWERS HAVE WANED EXCEPT FOR ONE WHICH WILL DIE IN
THE NEXT 30 MINUTES OVER CUMBERLAND COUNTY. SKIES WILL CLEAR
DURING MID TO LATE EVENING AS SPRAWLING HIGH PRES BUILDS SEWD
ACRS THE LWR LKS. THIS WILL BRING A CHILLY NIGHT TO THE
REGION...WITH TEMPS SLIPPING BACK INTO THE 30S AND 40S. A FROST
ADVISORY HAS BEEN POSTED FOR THE NORTHERN TIER.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL MAINTAIN ITS GRIP ON THE REGION THRU WEDNESDAY
BEFORE SLOWLY RETREATING OFF THE SRN NEW ENGLAND COAST THURSDAY
NIGHT. A MILDER RETURN S-SW FLOW WILL BRING ABOUT A SLOW
MODERATION IN DAILY MAX/MIN TEMPS WITH A GRADUAL INCREASE IN
HUMIDITY. TOMORROW NIGHT WILL AGAIN BE CHILLY ACROSS THE NRN TIER
WITH PATCHY FROST POSSIBLE...WITH IS HIGHLIGHTED IN THE HWO.
SCT CONVECTION IS POSSIBLE OVER THE WRN AND CNTRL ZONES THU
AFTN INTO THU NGT...AS WARM FRONT BEGINS TO LIFT NEWD FROM THE
UPPER OH VLY INTO WRN PA.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
TEMPERATURES SHOULD PEAK ON FRIDAY AS THE AREA BREAKS INTO THE WARM
SECTOR AHEAD OF A WELL-DEFINED COLD FRONT PUSHING EWD THRU THE GRT
LKS/OH VLY. THERE ARE SOME MINOR TIMING DIFFS CONCERNING THE COLD
FROPA ON SATURDAY...WITH THE GFS/GEFS A LITTLE MORE PROGRESSIVE
THAN THE ECMWF. DECENT SURGE OF MSTR WITH ABV NORMAL PWATS AHEAD
OF THE FRONT SHOULD PROMOTE SCT CONVECTIVE RAINS ON DAY 5 AND 6.
SOME SHOWER ACTIVITY MAY LINGER INTO SUNDAY WITH THE UPPER TROUGH
PASSAGE...BEFORE HIGH PRESSURE BRINGS A COOLING TREND WITH DRY WX
FROM LATE IN THE WEEKEND INTO EARLY NEXT WEEK.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
EARLY EVENING VISIBLE LOOP SHOWS SCT CU ACROSS MOST OF CENTRAL PA
WITH WIDESPREAD VFR CONDS. LOW LVL MOISTURE TRAPPED BENEATH
INVERSION IS RESULTING IN LOW CIGS JUST NORTH OF THE PA BORDER AND
CONCERN IS THAT SOME OF THESE LOW CIGS WILL CREEP INTO BFD EARLY THIS
EVENING BEFORE MUCH DRIER AIR ARRIVES LATE THIS EVENING. THE
LEADING EDGE OF THIS DRIER AIR MASS IS EVIDENT BY RAPID CLEARING
TAKING PLACE ALONG THE SOUTH SHORE OF LK ONTARIO AT 21Z. WOULD NOT
RULE OUT A PERIOD OF IFR CIGS AT BFD BTWN 23Z-03Z. RAP SOUNDINGS
SHOWS THE MUCH DRIER AIR ARRIVING ARND 03Z...AFTER WHICH MAINLY
CLEAR SKIES EXPECTED ACROSS ALL OF CENTRAL PA.
DIMINISHING WINDS...COOL TEMPS AND RELATIVELY WARM RIVER/STREAM
WATER...COULD RESULT IN PATCHY FOG IN THE DEEP VALLEYS OF THE
ALLEGHENIES EARLY TUE AM. CLIMATOLOGY WOULD INDICATE BFD AND IPT
COULD SEE A BRIEF VIS/CIG REDUCTION ARND DAWN.
LARGE HIGH PRESSURE SYSTEM AND ASSOCIATED DRY AIR MASS WILL BE OVR
THE REGION LATER TUESDAY...ENSURING A NEAR CERTAINTY OF MSUNNY
SKIES AND LIGHT WINDS.
OUTLOOK...
WED-THU...NO SIG WX. WIDESPREAD VFR.
FRI...ISOLD PM TSRA IMPACTS POSSIBLE W MTNS.
SAT...RAIN LIKELY WITH COLD FRONTAL PASSAGE. MVFR POSS MAINLY NW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 2 AM TO 8 AM EDT TUESDAY FOR PAZ004>006-
037-041-042.
&&
$$
SYNOPSIS...RXR
NEAR TERM...DEVOIR/RXR
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
942 PM CDT MON SEP 16 2013
.UPDATE...
Increased POPS sightly across southern sections overnight.
&&
.DISCUSSION...
Convection has diminished considerably across the Big Country this
evening with only some light showers remaining. Meanwhile, a new
area of showers and a few thunderstorms are developing across
southeast counties with additional development farther southeast
across the Hill Country. Most of the models are of little help this
evening but the RUC does show an increase in activity along the
I-10 corridor by early morning. Given the latest convective trends,
have increased POPS to 40 percent across the south and will maintain
20 to 30 percent elsewhere for the overnight period. The rest of
the forecast looks on track with no other changes needed at this
time.
&&
.PREV DISCUSSION... /ISSUED 613 PM CDT MON SEP 16 2013/
DISCUSSION...
See aviation discussion below...
AVIATION...
Scattered showers and thunderstorms have decreased across much of
West Central Texas during the last hour or so. I still expect
isolated showers and thunderstorms through at least 02z, and this is
reflected in the TAFs. A couple of outflow boundaries are moving
toward KSJT, and this could result in brief gusty variable winds.
Isolated to scattered showers and thunderstorms will be possible on
Tuesday, but I have left any mention out of the TAF package due to
low confidence. Overall, expect VFR conditions to prevail through
the next 24 hours.
PREV DISCUSSION... /ISSUED 409 PM CDT MON SEP 16 2013/
SHORT TERM...
(Tonight and Tuesday)
Upper level high pressure is currently resting across much of Texas
and east into the Gulf of Mexico. This high pressure will be fixed
through Tuesday evening, setting up south southeasterly flow across
the area. This will assist in funneling moisture from Tropical
Storm Ingrid and the remnants of Manuel into West Central Texas.
With this flow pattern we expect the best chances of rainfall across
our southwestern counties. We expect theses showers and
thunderstorms to be diurnally driven, given the lack of capping and
upper level support.
Adjusted the overnight lows into the upper 60s and near 70 to
account for the influx of moisture and expected cloud cover.
Afternoon highs will be near normal with temperatures in the upper
80s to near 90.
18
LONG TERM...
(Tuesday Night through Monday)
.Rain Chances Increase with Locally Heavy Rainfall Possible...
The main forecast focus revolves around rain chances Wednesday-
Friday, and the possibility of locally heavy rainfall. There is
also potential for greater coverage of rainfall across our area.
The upper high will shift a bit east and by Wednesday become
centered over the northern Gulf of Mexico. Our area will be on its
western periphery. The 12Z GFS and ECMWF show an upper reflection
from the remnants of Ingrid moving north out of Mexico and into
West Texas on Wednesday, followed by another upper level
disturbance (possible remnants of tropical system near the western
coast of Mexico) moving north- northeast into West Central Texas
by Thursday morning. We have low POPs at this time Wednesday and
Wednesday night, increasing Thursday. These may need to be raised
substantially if subsequent model runs remain consistent. Locally
heavy rainfall will be possible, with precipitable water values
increasing to between 1.5 and 2 inches.
On Friday, an upper trough moving into the Midwest will send a cold
front south into Texas, with the front progged to sag south into
West Central Texas. With a moist airmass remaining in place, could
have additional showers and thunderstorms across our area.
Carrying chance POPs Friday and these also may need to be increased.
Drier conditions are indicated for our area next weekend with upper
shortwave ridge building back into Texas.
19
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 92 71 89 70 92 / 30 20 20 10 10
San Angelo 92 70 88 69 92 / 30 30 30 10 10
Junction 91 70 87 69 91 / 30 40 30 10 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
24
AREA FORECAST DISCUSSION
NWS SPOKANE WA
248 PM PDT Sun Sep 15 2013
.SYNOPSIS...
Widespread showers and thunderstorms will occur over the Pacific
Northwest tonight as a vigorous cold front moves through the
region. Locally heavy rain and gusty winds will be possible this
evening over much of central and eastern Washington. The cold
front will bring an end to the record breaking heat. By Monday,
afternoon temperatures will fall into the 70s. Cooler and
occasionally showery weather is expected to persist through much
of the week.
&&
.DISCUSSION...
Tonight: Clusters of showers and thunderstorms are expected to
traverse the Inland Northwest tonight. We have talked extensively
the last few days about the phasing of two low pressure systems
along the coast and the negatively tilted 500mb trough progged to
move over the region tonight. As of 2PM, thunderstorms were
organizing over Oregon over the high terrain around Burns and also
in the vicinity of a deepening surface low near Pendleton. Surface
based instability (CAPE of 800-1100J/KG per RUC analysis) will
fuel rapid development of storms over Oregon late this afternoon.
Dewpoints around Tri-Cities and Pendleton are in the low to mid
50s. Oregon and south central Washington look to have a good shot
of strong to severe thunderstorms capable of damaging wind and
hail. Further north (central and northeast Washington), the
environment appears to be marginal for sustaining strong
convection. A persistent east wind the last few days has generated
a relatively dry boundary layer. Dewpoints from Sandpoint to
Spokane to Pullman to Wenatchee are generally in the upper 40s.
LAPS and RUC analysis shows very little surface based instability
which may end up being detrimental to sustaining strong storms
this evening. We will monitor the situation closely. As the
surface low near Pendleton kicks northward this evening it is
possible that low level moisture will traverse along with the low
and fuel strong storms along the way. There may also be enough
shear and mid-level instability with the vigorous, negatively
tilted trough to maintain storm organization into Wenatchee, Moses
Lake, Pullman and Spokane.
A Flash Flood Watch remains in effect for the burn scar areas
around Wenatchee, Chelan and Leavenworth through 11 PM. Tonight`s
system is probably not as favorable for flash flooding as others
we have seen this summer. Tonight`s system will be more
progressive and mid-level flow should be strong enough to produce
storm motion of 20-30mph. Yet, with the high mid-level moisture
content of the atmosphere and strong forcing, it is possible that
the burn scars could experience a couple rounds of heavy rain this
evening. Certainly worth heightening awareness of these vulnerable
areas with a watch.
Monday: The cold front will be into western Montana by daybreak on
Monday. Morning showers will linger over northeast Washington and
the Idaho Panhandle under the cold core. Strong mid-level dry
advection should bring a more stable air mass to the Idaho
Panhandle during the afternoon hours and we should see a general
decrease in shower activity through the day. Scattered showers and
thunderstorms will be slower to move out of northeast and north
central Washington around Colville and Republic where mid level
moisture will be slower to evacuate. Fall will arrive behind the
cold front. High temperatures will be much more typical of mid
September on Monday with 70s the rule for most of the Inland
Northwest. /GKoch
Monday night through Thursday morning...The brief break in the
weather early in the week will give way to another trough that
will bring showers and thunderstorms to the Inland Northwest. The
trough will move from southwest to northeast, perhaps lifting
northward a little further east than the current system. As a
result, precipitation chances ramp up during the afternoon on
Tuesday and continue into Wednesday night. The western Columbia
Basin into the Waterville Plateau may miss out on a lot of the
precipitation given the track of the storm. However, if the track
is further to the west then chances for precipitation will
increase. The moisture associated with this system will not be as
great as what we will experience this evening/tonight, but PW
values are going to be about 120 to 140 percent of normal, so some
localized heavier rainfall is possible, especially over far
eastern Washington into the Idaho panhandle. Chances for
precipitation will continue over the eastern higher terrain on
Wednesday with the trough not completely out of the region. But
the clouds and rainfall should clear out by Thursday morning.
Temperatures will be cool for mid- September, with Tuesday and
Wednesday afternoon topping out a few degrees below normal.
A quiet day is in store for Thursday, although it will be a
chilly when you wake up. A transient shortwave ridge will
traverse eastern Washington and the Idaho panhandle. A nice
rebound in temperatures will occur Thursday afternoon, with
readings topping out a few degrees above normal. ty
Thursday Night through Sunday: The short lived ridge will exit to
the east allowing another trough of low pressure to influence the
region. The trough and associated cold front will bring lower
temperatures and another good chance for widespread precipitation
across the region. Friday will bring the warmest and nicest day
of the period with strong SW flow ahead of the frontal system that
will push temperatures a handful of degrees above normal. Winds on
Friday will also be mostly terrain driven and remain light.
Friday afternoon is when the system will reach the Cascades
bringing increased precipitation chances. Overnight Friday into
Saturday the remainder of the region will stand the best chance
for precipitation. For right now the areas that will receive the
most rainfall from the system will be the Cascades along with the
NE Washington and ID Panhandle Mountains. The Basin currently
still remains questionable as models are wanting to shadow this
area. I went ahead and added slight chance of thunder for Saturday
based on weak CAPE values and due to the passage of the low center
over the region during this time frame.
Winds will be on the rise once again with the passage of the
front and then also with post frontal winds. Strongest winds look
to be on Saturday afternoon and evening. This system will likely
have some similarities with the system passing today and tomorrow.
Temperatures with the frontal passage will dip back below normal
remaining in the 60s and low 70s for most over the weekend.
Models then hint at another flat ridge after the trough exits to
the east which would bring lower chances for precipitation before
another system takes aim at the region for next week. /Fliehman
&&
.AVIATION...
18Z TAFS: A vigorous cold front will produce showers and
thunderstorms from late this afternoon through Monday morning. The
12z GFS is preferred for the general timing of the convection over
eastern Washington and north Idaho. Gusty outflow winds and brief
heavy rains will accompany the strongest cells this evening. There
is a chance for a ragged stratus deck Monday morning behind the
cold front at Spokane and Coeur D`Alene, especially if rains are
widespread enough to moisten the boundary layer. /GKoch
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 60 73 52 70 47 68 / 70 30 10 40 60 10
Coeur d`Alene 60 70 51 69 47 66 / 70 40 10 50 60 20
Pullman 58 72 46 69 41 68 / 60 20 10 50 50 10
Lewiston 64 81 57 75 52 73 / 60 10 10 40 50 10
Colville 61 73 49 72 46 70 / 80 70 20 60 50 40
Sandpoint 59 68 47 68 43 63 / 60 60 20 50 90 40
Kellogg 58 69 49 68 45 62 / 60 60 10 60 90 30
Moses Lake 62 77 52 74 48 74 / 70 10 10 20 10 10
Wenatchee 61 73 56 72 52 72 / 70 10 10 20 10 10
Omak 62 76 52 74 48 73 / 70 30 10 20 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Flash Flood Watch until 11 PM PDT this evening for East Slopes
Northern Cascades-Wenatchee Area.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1156 AM PDT Sun Sep 15 2013
.SYNOPSIS...
The late summer warm spell will come to an end tonight after one
more day of well above average temperatures. A strong cold front
will sweep through the region, and bring a round of thunderstorms
and gusty winds tonight. Cooler and more seasonable weather can be
expected for next week along with a chance of showers.
&&
.DISCUSSION...
The majority of the morning model runs are in, and the timing of
the cold front is in line with our previous forecast. It still
looks like scattered thunderstorms will be possible late this
afternoon over the central and northern Washington Cascades.
Isolated thunderstorms can`t be ruled out for late this afternoon
over eastern Washington and north Idaho (south of Interstate-90).
However, the best concentration of thunderstorms will likely be
during the evening and overnight hours with the arrival of the
surface front and upper trough axis. I think that the 12z GFS
depiction of convection (which is several hours later) is better
than the 12z NAM. Surface observations through late morning show
dewpoints in the mid and upper 40s over the Idaho Panhandle and
the majority of eastern Washington which the GFS handles better
than the NAM. There will be a shift in the wind direction this
afternoon from east to south which may increase boundary layer
moisture/surface based instability late in the afternoon. However,
it looks like the NAM dewpoint progs moisten the low levels too
quickly and generate what appears to be surface based convection
too quickly over the Panhandle and the eastern third of
Washington. Perhaps the NAM is releasing model instability via
high based convection this afternoon. If this is the case, the
model is already producing too much convection over Idaho and
Oregon as of 18z (11AM PDT).
Why is the timing of thunderstorms so important? The earlier in
the day thunderstorms reach eastern Washington and northern Idaho,
the better chance they will have to produce strong winds and hail.
The GFS and HRRR suggest that peak thunderstorm activity will be
from mid evening through a few hours after midnight which may
limit the wind potential.
The flash flood threat for the Cascades looks to be lower than
some of our recent late summer events. Tonight`s upper trough is
more progressive which should limit the window for heavy rain over
the burn scars. However, the abundance of mid-level moisture and
vigorous forcing will raise the potential for brief heavy rain
rates. The hours of greatest concern for Wenatchee will be from
5 PM to 10 PM. /GKoch
&&
.AVIATION...
18Z TAFS: A vigorous cold front will produce showers and
thunderstorms from late this afternoon through Monday morning. The
12z GFS is preferred for the general timing of the convection over
eastern Washington and north Idaho. Gusty outflow winds and brief
heavy rains will accompany the strongest cells this evening. There
is a chance for a ragged stratus deck Monday morning behind the
cold front at Spokane and Coeur D`Alene, especially if rains are
widespread enough to moisten the boundary layer. /GKoch
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 89 60 74 52 70 47 / 20 60 50 10 30 50
Coeur d`Alene 88 57 72 51 69 47 / 20 60 60 20 40 60
Pullman 89 58 74 46 69 41 / 20 60 30 10 50 50
Lewiston 93 64 81 57 75 52 / 20 50 20 10 40 50
Colville 91 57 75 49 72 45 / 10 80 60 50 60 60
Sandpoint 86 54 70 47 68 43 / 10 70 60 40 50 90
Kellogg 87 55 70 49 67 45 / 20 70 60 30 60 90
Moses Lake 92 61 79 52 75 48 / 30 70 10 10 20 10
Wenatchee 88 61 76 56 72 52 / 30 70 20 10 20 10
Omak 90 60 78 52 74 48 / 10 70 50 20 30 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Flash Flood Watch from 5 PM this afternoon to 11 PM PDT this
evening for East Slopes Northern Cascades-Wenatchee Area.
&&
$$
THE AREA FORECAST DISCUSSION FOUND BELOW.
WARMING TEMPERATURES ALOFT AND COOLING LOW LEVELS WILL MOSTLY
SHUTOFF PRECIPITATION CHANCES TONIGHT ALTHOUGH A FEW LINGERING
SHOWERS NOT OUT OF THE QUESTION DUE TO WEAK ELEVATED THETAE
ADVECTION. THERE WILL BE MORE SHOWERS AND THUNDERSTORMS MONDAY AS
A SHORTWAVE TROUGH PUNCHES ACROSS THE AREA. AS THE TROUGH MOVES
EAST WILL START TO SEE CLEAR FROM WEST TO EAST LATE IN THE DAY AND
CONTINUING THROUGH THE EVENING.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 323 AM MDT SUN SEP 15 2013
MODELS CONTINUE TO INDICATE A MUCH DRIER AND MORE NORMAL PATTERN
FROM TUESDAY THROUGH THE WEEKEND. PROGRESSIVE TROUGH MOVING INTO
THE PACIFIC NORTHWEST ON TUESDAY WILL CAUSE SOUTHWESTERLY MIDLEVEL
FLOW TO STRENGTHEN ACROSS THE REGION. 700MB TEMPS RISE TO A WARM
13C SO TEMPS WILL BE ABOVE NORMAL BY ABOUT 5-10 DEGREES. SOUTHWEST
WINDS WILL BE BREEZY ALONG AND WEST OF THE LARAMIE RANGE IN THE
AFTN. TROUGH MOVES ACROSS MONTANA ON WEDNESDAY AND THEN INTO THE
DAKOTAS BY THURSDAY. WEDNESDAY WILL BE ANOTHER WARM DAY WITH
GOOD DOWNSLOPING. LOW AND MIDLEVEL MOISTURE IS PRETTY MEAGER WITH
THIS SYSTEM...BUT DO HAVE SLIGHT CHANCE POPS OVER THE PLAINS ON
WEDNESDAY NIGHT IN THE CONVERGENCE ALONG THE COLD FRONT. SFC HIGH
MOVES OVERHEAD ON THURSDAY AND FRIDAY AND WITH COOLER TEMPS...IT
WILL BE VERY NICE SEPTEMBER DAYS. EXPECT WARMER TEMPS DURING THE
WEEKEND AS SOUTHWESTERLY FLOW ALOFT BECOMES ESTABLISHED ONCE AGAIN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 1050 PM MDT SAT SEP 14 2013
LATEST HRRR GUIDANCE SHOWING A WIDESPREAD IFR/LIFR EVENT TAKING
SHAPE AS A COLD FRONT PUSHES SOUTH INTO NORTHERN COLORADO.
NORTHEAST UPSLOPING WINDS WILL PERSIST MOST OF THE NEXT 24-36
HOURS AND BRING DOWN CEILINGS AT AIRPORTS EAST OF THE LARAMIE
RANGE SHORTLY AFTER 08Z AT CHADRON...THEN SPREADING QUICKLY SOUTH
AND SOUTHWEST. WE COULD STAY DOWN ALL DAY SUNDAY AND MAYBE GO TO
MVFR DURING THE AFTERNOON. WITH UPSLOPING WINDS AND COOL
TEMPERATURES...DO EXPECT IFR/LIFR TO RETURN SUNDAY NIGHT.
&&
.FIRE WEATHER...
ISSUED AT 323 AM MDT SUN SEP 15 2013
SHOWERS AND THUNDERSTORMS WILL AGAIN OCCUR OVER SOUTHEAST WYOMING
TODAY WHILE SHOWERS SHOULD END THIS MORNING OVER THE NEBRASKA
PANHANDLE. MOST SHOWER ACTIVITY WILL BE FOUND ALONG AND WEST OF THE
LARAMIE RANGE. A FLASH FLOOD WATCH IS IN EFFECT FOR THE SOUTHERN
LARAMIE RANGE AND FOOTHILLS WHERE THE SOIL IS SATURATED AND PRONE
TO RAPID RUNOFF SHOULD THUNDERSTORMS DEVELOP OVER THE AREA. SHOWERS
AND THUNDERSTORMS WILL MOSTLY DISSIPATE THIS EVENING BUT ONE MORE
ROUND OF SHOWERS AND THUNDERSTORMS IS POSSIBLE MONDAY AFTERNOON...
THEN DRIER WEATHER FOR THE REST OF THE WEEK.
&&
.HYDROLOGY...
ISSUED AT 227 PM MDT SAT SEP 14 2013
FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH THIS AFTERNOON FOR
THE SOUTHERN LARAMIE RANGE AND FOOTHILLS. POTENTIAL FOR FLOODING
STILL EXISTS ALTHOUGH THAT IS PREDICATED ON ELEVATED THUNDERSTORMS
DEVELOPING THIS AFTERNOON WHICH IS NOT A CERTAINTY OVER THE
LARAMIE RANGE. LOW LEVEL INVERSION WILL SET UP WITH THE PASSAGE
OF A COLD FRONT WHICH MEANS SURFACE BASED THUNDERSTORMS NOT LIKELY
OVER THE LARAMIE RANGE OR POINTS EAST. THE MODLES DO POINT AS 20
TO 30 KT SOUTHEAST WIND DEVELOPING NEAR THE TOP OF THE INVERSION
NEAR THE SOUTHERN LARAMIE RANGE WITH STEEP ELEVATED LAPSE RATES IN
PLACE. THIS MAY BE ENOUGH TO POP A FEW ELEVATED THUNDERSTORMS
WHICH THEN WOULD HAVE TO POTENTIAL TO PRODUCE FLASH FLOODING.
ALSO...FLASH FLOOD GUIDANCE VALUES ARE VERY LOW SO IT WILL NOT TAKE
MUCH HEAVY RAIN TO CAUSE FLASH FLOODING. WILL ALSO SEE A PERIOD OF
MODERATE STRATAFORM RAINFALL THIS MORNING OVER THE AREA WHICH WILL
KEEP THE SOIL VERY SATURATED.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR WYZ116-117.
NE...NONE.
&&
$$
SHORT TERM...LIEBL
LONG TERM...FINCH
AVIATION...CLAYCOMB
FIRE WEATHER...LIEBL
HYDROLOGY...LIEBL
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1210 AM MDT SUN SEP 15 2013
.UPDATE...
ISSUED AT 1207 AM MDT SUN SEP 15 2013
EXTENDED FLASH FLOOD WATCH OVER THE SOUTHERN LARAMIE RANGE AND
NEARBY FOOTHILLS THROUGH THIS AFTERNOON. CANCELLED THE SNOWY RANGE
WATCH. MAIN CHANCE FOR FLOODING RAIN SHOULD BE THIS AFTERNOON. MORE
DETAILS WILL BE PROVIDED WITH THE MORNING AREA FROECAST DISCUSSION.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 315 PM MDT SAT SEP 14 2013
CURRENT KCYS RADAR LOOP SHOWS SHOWERS AND TSTORMS DEVELOPING
ACROSS THE MOUNTAINS AND SLOWLY MOVING EAST/NORTH EAST ACROSS
SOUTHEAST WYOMING. RADAR PRECIP ESTIMATES ALREADY SHOWING A FEW
AREAS OF RAINFALL RATES ABOVE ONE INCH PER HOUR. A FLASH FLOOD
WATCH WILL CONTINUE THROUGH LATE THIS EVENING. THE UPPER LEVEL LOW
WHICH RESULTED IN THE WIDESPREAD FLOODING ACROSS THE SOUTHWEST AND
THE FRONT RANGE WILL WEAKEN TONIGHT AND PUSH EAST INTO COLORADO.
IN ADDITION...A COOL FRONT WILL MOVE ACROSS EASTERN WYOMING AND
NEBRASKA LATE THIS AFTERNOON AND THROUGH LATE THIS EVENING.
UPSLOPE FLOW COMBINED WITH INSTABILITY AND MOISTURE WILL LIKELY
KEEP THE TSTORM ACTIVITY GOING FOR A WHILE TONIGHT BEFORE THE
PRECIP BECOMES MORE STRATIFORM IN NATURE LATE. MODELS SHOW QUITE A
BIT OF QPF ALONG THE FRONT RANGE...EXTENDING INTO SOUTHEAST
WYOMING. THE 12Z NAM AND GEM SHOW OVER AN INCH OF ADDITIONAL
RAINFALL ALONG THE LARAMIE RANGE INCLUDING THE ADJACENT HIGH
VALLEYS OF ALBANY COUNTY AND HIGH PLAINS OF PLATTE/LARAMIE COUNTY.
INCREASED POP IN THESE AREAS TONIGHT AND INTO SUNDAY MORNING.
HOWEVER...THERE IS STILL UNCERTAINTY WITH HOW MUCH RAIN WILL FALL.
GFS AND ECMWF SHOW AROUND A THIRD TO HALF AN INCH OF RAINFALL WITH
THIS FEATURE...SO ONLY KEPT THE FLASH FLOOD WATCH GOING UNTIL
MIDNIGHT TONIGHT. WILL LET THE EVENING AND MIDNIGHT SHIFT DECIDE
IF IT NEEDS TO BE EXTENDED THROUGH SUNDAY. CURRENT THINKING IS THE
RAINFALL WILL BE MORE LIGHT TO MODERATE IN INTENSITY. PATCHY DENSE
FOG IS LIKELY TO DEVELOP ONCE AGAIN TONIGHT DUE TO THE MOIST
UPSLOPE FLOW...ESPECIALLY ACROSS SOUTHEAST WYOMING.
FOR SUNDAY...ANOTHER COOL DAY IS EXPECTED BEHIND THE COOL FRONT WITH
TEMPERATURES RETURNING TO THE UPPER 50S TO UPPER 60S. IT WILL BE
MORE STABLE ON SUNDAY...SO DO NOT EXPECT AS MUCH HEAVY RAINFALL.
LIGHT TO MODERATE RAIN AND DRIZZLE APPEARS LIKELY ALONG AND WEST OF
THE LARAMIE RANGE THROUGH SUNDAY EVENING...AND MAY EVEN LINGER
NEAR THE SOUTHERN LARAMIE RANGE INTO EARLY MONDAY MORNING.
THE WEAKENING UPPER LEVEL TROUGH WILL MOVE ACROSS SOUTHEAST
WYOMING AND EASTERN COLORADO EARLY ON MONDAY. SOMEWHAT DRIER AIR
WILL BEGIN TO MOVE INTO THE REGION DURING THE DAY WITH HIGH
TEMPERATURES RETURNING TO THE 70S. CAN NOT RULE OUT WIDELY
SCATTERED SHOWERS AND TSTORMS OVER SOUTHEAST WYOMING DURING THE
AFTERNOON DUE TO INSTABILITY AND LINGERING MOISTURE. INCREASED POP
BETWEEN 20 TO 40 PERCENT...HIGHEST AROUND THE LARAMIE RANGE. A
SHORTWAVE RIDGE WILL MOVE INTO THE FORECAST AREA MONDAY
NIGHT...RESULTING IN DRIER CONDITIONS AND POP BELOW 5 PERCENT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 242 PM MDT SAT SEP 14 2013
FINALLY...WARMER AND DRIER WEATHER WILL BE IN TAP FOR THE CWA
THROUGH THE EARLY PART OF NEXT WEEKEND. A SHORTWAVE TROUGH EXITS
THE REGION BY 12Z TUESDAY AND IS REPLACED BY A DRIER SOUTHWEST
WIND FLOW FOR TUESDAY AND INTO TUESDAY NIGHT. A LARGER AMPLITUDE
SHORTWAVE TROUGH...CURRENTLY NEAR 50N AND 145W...WILL MOVE EAST
AND ACROSS THE CWA WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT. MODELS
DIFFER ON AMPLITUDE AND TIMING OF THE FEATURE WITH THE GFS FASTER
AND WITH LESS AMPLITUDE THAN THE OTHER MEDIUM RANGE MODELS. THE
ASSOCIATED SURFACE COLD FRONT MOVES ACROSS THE CWA WEDNESDAY
AFTERNOON. WESTERLY WINDS WILL GUST AS HIGH AS 40 MPH AHEAD AND
THEN BEHIND THE FRONT WEDNESDAY AND WEDNESDAY EVENING. GUSTY WINDS
MAY ALSO OCCUR THROUGH THURSDAY ON THE BACKSIDE OF THE NEWLY
FORMED NORTHERN PLAINS CLOSED MID LEVEL LOW. TEMPERATURES WILL ALSO
COOL BEHIND THE FRONT WITH 60S TO MID 70S COMMON FOR DAYTIME HIGHS
ACROSS THE LOWER ELEVATIONS THURSDAY AND POSSIBLY FRIDAY. THE
TEMPERATURES SHOULD WARM SOME FOR NEXT SATURDAY.
POPS WILL BE THE QUESTION OVER THE CWA WEDNESDAY AND THURSDAY AND
POSSIBLY AGAIN NEXT SATURDAY. THE 12Z ECMWF IS TRENDING FURTHER
SOUTH WITH THE CLOSED MID LEVEL LOW FOR THURSDAY AND PAINTS MORE
QPF THAN ITS PREVIOUS RUN AS WELL AS THE GFS. MOST POPS WILL BE
OVER AND NEAR THE MOUNTAINS ON WEDNESDAY AND THURSDAY...BUT THE
POSSIBLE CYCLONIC FLOW ALOFT MAY PRODUCE MORE SHOWERS OVER THE CWA
ON THOSE DAYS. HAVE BUMPED UP POPS A BIT OVER THE CWA FOR WEDNESDAY
AND THURSDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 1050 PM MDT SAT SEP 14 2013
LATEST HRRR GUIDANCE SHOWING A WIDEPSREAD IFR/LIFR EVENT TAKING
SHAPE AS A COLD FRONT PUSHES SOUTH INTO NORTHERN COLORADO.
NORTHEAST UPSLOPING WINDS WILL PERSIST MOST OF THE NEXT 24-36
HOURS AND BRING DOWN CEILINGS AT AIRPORTS EAST OF THE LARAMIE
RANGE SHORTLY AFTER 08Z AT CHADRON...THEN SPREADING QUICKLY SOUTH
AND SOUTHWEST. WE COULD STAY DOWN ALL DAY SUNDAY AND MAYBE GO TO
MVFR DURING THE AFTERNOON. WITH UPSLOPING WINDS AND COOL
TEMPERATURES...DO EXPECT IFR/LIFR TO RETURN SUNDAY NIGHT.
&&
.FIRE WEATHER...
ISSUED AT 227 PM MDT SAT SEP 14 2013
NO FIRE WEATHER CONCERNS THROUGH NEXT WEEK. MOIST CONDITIONS WILL
CONTINUE THROUGH THE WEEKEND WITH AFTERNOON HUMIDITY VALUES
GENERALLY ABOVE 50 PERCENT. SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WILL DEVELOP THIS AFTERNOON...WITH SOME OF THE
SHOWERS PRODUCING LOCALLY HEAVY RAIN. A FRONT WILL MOVE ACROSS THE
AREA TONIGHT WITH MOIST UPSLOPE WINDS ON SUNDAY AND NUMEROUS RAIN
SHOWERS. WARMER AND DRIER CONDITIONS ARE EXPECTED ACROSS THE
REGION BY THE MIDDLE PART OF NEXT WEEK...WITH DAYTIME HUMIDITIES
BETWEEN 25 TO 40 PERCENT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR WYZ116-117.
NE...NONE.
&&
$$
UPDATE...LIEBL
SHORT TERM...TJT
LONG TERM...WEILAND
AVIATION...CLAYCOMB
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1054 PM MDT SAT SEP 14 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 315 PM MDT SAT SEP 14 2013
CURRENT KCYS RADAR LOOP SHOWS SHOWERS AND TSTORMS DEVELOPING
ACROSS THE MOUNTAINS AND SLOWLY MOVING EAST/NORTH EAST ACROSS
SOUTHEAST WYOMING. RADAR PRECIP ESTIMATES ALREADY SHOWING A FEW
AREAS OF RAINFALL RATES ABOVE ONE INCH PER HOUR. A FLASH FLOOD
WATCH WILL CONTINUE THROUGH LATE THIS EVENING. THE UPPER LEVEL LOW
WHICH RESULTED IN THE WIDESPREAD FLOODING ACROSS THE SOUTHWEST AND
THE FRONT RANGE WILL WEAKEN TONIGHT AND PUSH EAST INTO COLORADO.
IN ADDITION...A COOL FRONT WILL MOVE ACROSS EASTERN WYOMING AND
NEBRASKA LATE THIS AFTERNOON AND THROUGH LATE THIS EVENING.
UPSLOPE FLOW COMBINED WITH INSTABILITY AND MOISTURE WILL LIKELY
KEEP THE TSTORM ACTIVITY GOING FOR A WHILE TONIGHT BEFORE THE
PRECIP BECOMES MORE STRATIFORM IN NATURE LATE. MODELS SHOW QUITE A
BIT OF QPF ALONG THE FRONT RANGE...EXTENDING INTO SOUTHEAST
WYOMING. THE 12Z NAM AND GEM SHOW OVER AN INCH OF ADDITIONAL
RAINFALL ALONG THE LARAMIE RANGE INCLUDING THE ADJACENT HIGH
VALLEYS OF ALBANY COUNTY AND HIGH PLAINS OF PLATTE/LARAMIE COUNTY.
INCREASED POP IN THESE AREAS TONIGHT AND INTO SUNDAY MORNING.
HOWEVER...THERE IS STILL UNCERTAINTY WITH HOW MUCH RAIN WILL FALL.
GFS AND ECMWF SHOW AROUND A THIRD TO HALF AN INCH OF RAINFALL WITH
THIS FEATURE...SO ONLY KEPT THE FLASH FLOOD WATCH GOING UNTIL
MIDNIGHT TONIGHT. WILL LET THE EVENING AND MIDNIGHT SHIFT DECIDE
IF IT NEEDS TO BE EXTENDED THROUGH SUNDAY. CURRENT THINKING IS THE
RAINFALL WILL BE MORE LIGHT TO MODERATE IN INTENSITY. PATCHY DENSE
FOG IS LIKELY TO DEVELOP ONCE AGAIN TONIGHT DUE TO THE MOIST
UPSLOPE FLOW...ESPECIALLY ACROSS SOUTHEAST WYOMING.
FOR SUNDAY...ANOTHER COOL DAY IS EXPECTED BEHIND THE COOL FRONT WITH
TEMPERATURES RETURNING TO THE UPPER 50S TO UPPER 60S. IT WILL BE
MORE STABLE ON SUNDAY...SO DO NOT EXPECT AS MUCH HEAVY RAINFALL.
LIGHT TO MODERATE RAIN AND DRIZZLE APPEARS LIKELY ALONG AND WEST OF
THE LARAMIE RANGE THROUGH SUNDAY EVENING...AND MAY EVEN LINGER
NEAR THE SOUTHERN LARAMIE RANGE INTO EARLY MONDAY MORNING.
THE WEAKENING UPPER LEVEL TROUGH WILL MOVE ACROSS SOUTHEAST
WYOMING AND EASTERN COLORADO EARLY ON MONDAY. SOMEWHAT DRIER AIR
WILL BEGIN TO MOVE INTO THE REGION DURING THE DAY WITH HIGH
TEMPERATURES RETURNING TO THE 70S. CAN NOT RULE OUT WIDELY
SCATTERED SHOWERS AND TSTORMS OVER SOUTHEAST WYOMING DURING THE
AFTERNOON DUE TO INSTABILITY AND LINGERING MOISTURE. INCREASED POP
BETWEEN 20 TO 40 PERCENT...HIGHEST AROUND THE LARAMIE RANGE. A
SHORTWAVE RIDGE WILL MOVE INTO THE FORECAST AREA MONDAY
NIGHT...RESULTING IN DRIER CONDITIONS AND POP BELOW 5 PERCENT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 242 PM MDT SAT SEP 14 2013
FINALLY...WARMER AND DRIER WEATHER WILL BE IN TAP FOR THE CWA
THROUGH THE EARLY PART OF NEXT WEEKEND. A SHORTWAVE TROUGH EXITS
THE REGION BY 12Z TUESDAY AND IS REPLACED BY A DRIER SOUTHWEST
WIND FLOW FOR TUESDAY AND INTO TUESDAY NIGHT. A LARGER AMPLITUDE
SHORTWAVE TROUGH...CURRENTLY NEAR 50N AND 145W...WILL MOVE EAST
AND ACROSS THE CWA WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT. MODELS
DIFFER ON AMPLITUDE AND TIMING OF THE FEATURE WITH THE GFS FASTER
AND WITH LESS AMPLITUDE THAN THE OTHER MEDIUM RANGE MODELS. THE
ASSOCIATED SURFACE COLD FRONT MOVES ACROSS THE CWA WEDNESDAY
AFTERNOON. WESTERLY WINDS WILL GUST AS HIGH AS 40 MPH AHEAD AND
THEN BEHIND THE FRONT WEDNESDAY AND WEDNESDAY EVENING. GUSTY WINDS
MAY ALSO OCCUR THROUGH THURSDAY ON THE BACKSIDE OF THE NEWLY
FORMED NORTHERN PLAINS CLOSED MID LEVEL LOW. TEMPERATURES WILL ALSO
COOL BEHIND THE FRONT WITH 60S TO MID 70S COMMON FOR DAYTIME HIGHS
ACROSS THE LOWER ELEVATIONS THURSDAY AND POSSIBLY FRIDAY. THE
TEMPERATURES SHOULD WARM SOME FOR NEXT SATURDAY.
POPS WILL BE THE QUESTION OVER THE CWA WEDNESDAY AND THURSDAY AND
POSSIBLY AGAIN NEXT SATURDAY. THE 12Z ECMWF IS TRENDING FURTHER
SOUTH WITH THE CLOSED MID LEVEL LOW FOR THURSDAY AND PAINTS MORE
QPF THAN ITS PREVIOUS RUN AS WELL AS THE GFS. MOST POPS WILL BE
OVER AND NEAR THE MOUNTAINS ON WEDNESDAY AND THURSDAY...BUT THE
POSSIBLE CYCLONIC FLOW ALOFT MAY PRODUCE MORE SHOWERS OVER THE CWA
ON THOSE DAYS. HAVE BUMPED UP POPS A BIT OVER THE CWA FOR WEDNESDAY
AND THURSDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 1050 PM MDT SAT SEP 14 2013
LATEST HRRR GUIDANCE SHOWING A WIDEPSREAD IFR/LIFR EVENT TAKING
SHAPE AS A COLD FRONT PUSHES SOUTH INTO NORTHERN COLORADO.
NORTHEAST UPSLOPING WINDS WILL PERSIST MOST OF THE NEXT 24-36
HOURS AND BRING DOWN CEILINGS AT AIRPORTS EAST OF THE LARAMIE
RANGE SHORTLY AFTER 08Z AT CHADRON...THEN SPREADING QUICKLY SOUTH
AND SOUTHWEST. WE COULD STAY DOWN ALL DAY SUNDAY AND MAYBE GO TO
MVFR DURING THE AFTERNOON. WITH UPSLOPING WINDS AND COOL
TEMPERATURES...DO EXPECT IFR/LIFR TO RETURN SUNDAY NIGHT.
&&
.FIRE WEATHER...
ISSUED AT 227 PM MDT SAT SEP 14 2013
NO FIRE WEATHER CONCERNS THROUGH NEXT WEEK. MOIST CONDITIONS WILL
CONTINUE THROUGH THE WEEKEND WITH AFTERNOON HUMIDITY VALUES
GENERALLY ABOVE 50 PERCENT. SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WILL DEVELOP THIS AFTERNOON...WITH SOME OF THE
SHOWERS PRODUCING LOCALLY HEAVY RAIN. A FRONT WILL MOVE ACROSS THE
AREA TONIGHT WITH MOIST UPSLOPE WINDS ON SUNDAY AND NUMEROUS RAIN
SHOWERS. WARMER AND DRIER CONDITIONS ARE EXPECTED ACROSS THE
REGION BY THE MIDDLE PART OF NEXT WEEK...WITH DAYTIME HUMIDITIES
BETWEEN 25 TO 40 PERCENT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR WYZ114-116-117.
NE...NONE.
&&
$$
SHORT TERM...TJT
LONG TERM...WEILAND
AVIATION...CLAYCOMB
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1011 PM MDT MON SEP 16 2013
.UPDATE...
ISSUED AT 901 PM MDT MON SEP 16 2013
A FEW SHOWERS AND THUNDERSTORMS CONTINUE TO PERSIST OVER THE UINTA
MTNS IN NORTHEAST UTAH THIS EVENING...AND ADJUSTED THE GRIDDED
FORECAST ACCORDINGLY. A FAIR AMOUNT OF LIGHTNING INDICATED WITH
SOME OF THESE THUNDERSTORMS. ELSEWHERE ACROSS THE FORECAST
AREA...SHOWERS HAVE DIED DOWN WITH THE LOSS OF SOLAR HEATING.
PRECIPITABLE WATER OF 0.64 INCH ON THIS EVENING/S GJT SOUNDING WAS
DOWN CONSIDERABLY FROM THE 0.94 INCH MEASURED THIS MORNING. A
QUICK LOOK AT THE 00Z NAM AND 00Z RAP MODELS SHOW A WEAK
DISTURBANCE CROSSING THE SOUTH LATER TONIGHT...AND THE CURRENT
FORECAST MAINTAINS MENTION OF AN ISOLATED SHOWER OR STORM POSSIBLE
OVER THE SAN JUAN MTNS AFTER MIDNIGHT.
&&
.SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT)
ISSUED AT 356 PM MDT MON SEP 16 2013
LOCAL PROFILERS AND WATER VAPOR IMAGERY SHOWING THE TROF THAT HAS
BEEN LINGERING IN THE WEST FINALLY PUSHING ONTO THE PLAINS THIS
AFTERNOON. WEAKER UPSTREAM WAVE IS MOVING IN BEHIND A TRANSITORY
RIDGE IN NORTHERN UTAH AND PROVIDING A BIT MORE FOCUS FOR STORMS IN
OUR WESTERN CWA...WITH HEATING DRIVING ISOLATED CONVECTION
ELSEWHERE. A DIP IN THE WESTERLIES IS MOVING ONTO THE WEST COAST
THIS AFTERNOON WHICH WILL BE DRIVING A SERIES OF STRONGER OPEN OUT
OF THE EASTERN PACIFIC BEGINNING TONIGHT.
SOUNDINGS SHOW SOME DRIER AIR MOVING INTO THE LOWER LAYERS OF THE
PROFILE BUT MOISTURE STILL HANGING AROUND 600-500MB KEEPING PWATS
ABOVE NORMAL. GOES DERIVED TPW VERIFIES THE MOISTURE HANGING AROUND
THE VEGAS/WESTERN GREAT BASIN AREA AND UPSTREAM OFF THE CALIFORNIA
COAST ASSOCIATED WITH THE WESTERN TROF. THETA SURFACES NEAR 315-320K
SHOW THE FLOW TURNING SOUTHWESTERLY AND INCREASING LATE TONIGHT INTO
TUESDAY AND DRAWING MOISTURE BACK INTO OUR CWA. PIECES OF THE UPPER
JET COMBINE WITH INCREASING LARGE SCALE ASCENT BY THE AFTERNOON
WHICH SHOULD BRING AN UPTICK TO THE CONVECTION. THE STORMS LOOK TO
LINGER THROUGH THE OVERNIGHT HOURS AS THE JET SLOWLY SAGS SOUTHWARD
AND ASCENT INCREASES. TEMPERATURES SHOULD BE MAKING A REBOUND TO
ABOVE NORMAL BY TOMORROW BEFORE A WEAK FRONT PASSES THROUGH THE MID
WEEK.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 356 PM MDT MON SEP 16 2013
A CHANGE IN PATTERN FROM THE STAGNANT MONSOON FLOW TO PROGRESSIVE
WESTERLIES OCCURS THIS WEEK...UNOFFICIALLY ENDING THE MONSOON
SEASON.
WEDNESDAY A PACIFIC TROUGH WORKS THROUGH THE NORTHERN ROCKIES. A
WARM SW GRADIENT WIND WILL MIX DOWN IN THE AFTERNOON FOR BREEZY
WARM CONDITIONS. RESIDUAL MOISTURE IS SUFFICIENT FOR SCATTERED
MAINLY MOUNTAIN SHOWERS AND STORMS. THE ASSOCIATED COOL AND
DRY FRONT PUSHES INTO NE UTAH IN THE AFTERNOON PUSHES THROUGH THE
NORTHERN AND CENTRAL ZONES BECOMING STRETCHED WEST TO EAST
SOMEWHERE NEAR THE HIGHWAY 50 LINE BY THURSDAY MORNING. THIS WILL
USHER IN A DRIER AND COOLER AIR MASS FOR THURSDAY. TEMPERATURES
ACROSS PORTIONS OF NW COLORADO WILL FLIRT WITH THE FREEZING.
TEMPERATURES WILL RECOVER ON FRIDAY INTO SATURDAY TO NEAR NORMAL.
THEN NEXT PACIFIC TROUGH IS CURRENTLY TIMED TO PASS LATE SUNDAY...
WITH ANOTHER TROUGH LATER NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1010 PM MDT MON SEP 16 2013
VFR IS EXPECTED TO BE THE PREVAILING CONDITION AT THE TAF SITES FOR
THE REMAINDER OF TONIGHT THROUGH TUESDAY. AN ISOLATED -SHRA OR -TSRA
IS POSSIBLE OVER THE SAN JUAN MTNS THROUGH 18Z TUE. ISOLATED TO
SCATTERED -TSRA ARE EXPECTED BETWEEN 18Z TUE AND 03Z WED WITH THE
GREATER COVERAGE OVER THE HIGHER TERRAIN. MVFR CIGS AND GUSTY
OUTFLOW WINDS NEAR THE -TSRA WITH SOME MOUNTAIN TOP OBSCURATIONS.
ALSO...SOUTH TO SOUTHWEST SURFACE GRADIENT WINDS INCREASE TUE
AFTERNOON.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...JAD
SHORT TERM...15
LONG TERM...JOE
AVIATION...JAD
AREA FORECAST DISCUSSION
NWS POCATELLO ID
337 AM MDT TUE SEP 17 2013
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT. A VERY ACTIVE 48 HOUR
PERIOD IS AHEAD FOR EASTERN IDAHO. WE ALREADY HAD A ROUND OF
STRONG/SEVERE STORMS THIS MORNING AND ANOTHER ROUND IS ON TAP FOR
LATER TODAY. THE MAIN FEATURE WITH STORM OFFSHORE WILL SWING INTO
WASHINGTON AND OREGON. THIS...ALONG WITH A COLD FRONT ENTERING
INTO WESTERN PORTIONS OF THE FORECAST AREA WILL KEEP SHOWERS AND
THUNDERSTORMS AROUND WITH COVERAGE RAMPING UP THIS AFTERNOON.
MOST AREAS WILL SEE SCATTERED TO NUMEROUS SHOWERS AND
STORMS...WITH EXCEPTION FOR THE MAGIC VALLEY AND WEST OF OAKLEY
WHERE ISOLATED ACTIVITY IS FORECAST. THE FRONT SHOULD BE THROUGH
THEM BEFORE THINGS GET GOING. THE THREAT OF STRONG/SEVERE STORMS
WITH HAIL AND STRONG WINDS EXISTS TODAY ESPECIALLY ACROSS THE
MOUNTAINS AND ALONG/AHEAD OF THE COLD FRONT ACROSS THE SNAKE
PLAIN. BY TONIGHT AND WEDNESDAY...THE FOCUS FOR SHOWERS WILL SHIFT
TO THE CENTRAL MOUNTAINS AND UPPER SNAKE HIGHLANDS. I KNOW SOME
AREN`T GOING TO BE READY OR LIKE THIS..BUT LIGHT SNOW IS FORECAST
ABOVE 7500FT TONIGHT/EARLY WEDNESDAY ACROSS THE CENTRAL MOUNTAINS.
YOU CAN EXPECT BREEZY/WINDY CONDITIONS ACROSS THE AREA...WITH
SOUTHERLY WINDS AHEAD OF THE FRONT AND MORE WESTERLY IN ITS WAKE.
SUSTAINED WINDS OF 15-30MPH WITH HIGHER GUSTS ARE LIKELY...OUTSIDE
OF THUNDERSTORMS...THROUGH THIS EVENING. THE RIDGETOPS MAY SEE
SUSTAINED WINDS CLOSER TO 30-35MPH AT THEIR PEAK. WIND SPEEDS COME
DOWN SOME ESPECIALLY ACROSS THE CENTRAL MOUNTAINS AND UPPER SNAKE
HIGHLANDS TONIGHT AND TOMORROW. THEY`LL STILL BE BREEZY ACROSS
MOST OF THE SNAKE PLAIN AND SOUTHERN MOUNTAINS HOWEVER. WE HAVE A
LAKE WIND ADVISORY OUT FOR THIS AFTERNOON UNTIL JUST BEFORE
SUNSET. ANOTHER ONE IS LIKELY FOR TOMORROW AS WELL. CONDITIONS ARE
JUST NOT QUITE THERE FOR A WIND ADVISORY AT LOWER ELEVATIONS BUT
WE WILL BE MONITORING THIS AS WINDS WILL BE FLIRTING WITH THE
LOWER THRESHOLD OF 30MPH SUSTAINED TOMORROW. IT WILL CERTAINLY
FEEL LIKE FALL WITH COLDER TEMPERATURES ARRIVING BEHIND THE FRONT.
WE ARE LOOKING AT A 10-15 DEGREE DIFFERENCE BETWEEN TODAY AND
TOMORROW...WITH THE VALLEYS STRUGGLING TO GET ABOVE 65. WEDNESDAY
NIGHT WILL BE DOWNRIGHT COLD IN SOME AREAS. IT LOOKS LIKE MANY
AREAS WILL SEE 20S AND 30S FOR LOWS. THE EXCEPTIONS WILL BE ACROSS
THE SOUTHERN HIGHLANDS WHERE VALLEY TEMPERATURES WILL BOTTOM OUT
IN THE LOW 40S..AND PLACES LIKE STANLEY AND COPPER BASIN WHERE IT
WILL DROP INTO THE TEENS. KEYES
.LONG TERM...THURSDAY THROUGH NEXT TUESDAY. THE END OF THE WEEK
WILL SEE HIGH PRESSURE BUILDING AND SHIFTING EASTWARD OVER IDAHO.
THIS WILL ALLOW FOR A QUICK WARMUP WITH DRY CONDITIONS THROUGH
SATURDAY MORNING. FOR THE TRUE ARRIVAL OF FALL EARLY NEXT
WEEK...THE OVERALL PATTERN SETTLES BACK INTO GENERAL LOW PRESSURE
OVER THE WEST. THERE WILL BE MULTIPLE SYSTEMS IN THE PATTERN THAT
WILL KEEP THE CHANCE OF SHOWERS AROUND WITH A FEW THUNDERSTORMS. KEYES
&&
.AVIATION...TRONG SHOWERS AND THUNDERSTORMS HAVE PASSED TO THE
DOWNWIND SIDE OF ALL AIRDROMES EXCEPT KIDA. -TSRA WILL CONTINUE AND
INCREASE IN COVERAGE AS INSTABILITY DEVELOPS AHEAD OF A COLD FRONT
EXPECTED LATE THIS AFTERNOON/EARLY THIS COMING EVENING...PASSING
THROUGH ALL AIRDROMES BY 18/03Z. -TSRA PROBABILITY BORDERS ON 50
PERCENT FOR KIDA AND KPIH...BUT TEMPO GROUPS NOT ALLOWED BEYOND 6
HOUR POINT. WILL TRY TO USE LATEST HRRR GUIDANCE TO FORECAST A
THUNDERSTORM TIME. FRONTAL PASSAGE IS FROM WEST TO EAST...WITH KIDA
BEING THE LAST. STRONG GRADIENT BEHIND THE FRONT MEANS AN UNUSUALLY
WINDY OVERNIGHT PERIOD TONIGHT. STRONG WIND CONTINUES WED AFTERNOON.
MESSICK
&&
.FIRE WEATHER...ERY UNSTABLE CONDITIONS TODAY WITH A FRONT ARRIVING
IN THE LATE AFTERNOON OVER EASTERN IDAHO. EXPECT A STORMY AND WINDY
DAY...CONTINUING INTO A STORMY AND WINDY NIGHT. FRONT WILL PASS OUT
OF EASTERN IDAHO BY MIDNIGHT TONIGHT...BUT STRONG WINDS WILL
CONTINUE OVERNIGHT AND INCREASE AGAIN TOMORROW AFTERNOON.
THUNDERSTORM ACTIVITY WILL BE LIMITED ON WED TO MAINLY THE TARGHEE
PORTION OF THE CARIBOU-TARGHEE NF. HIGH PRESSURE WILL MOVE IN FOR
THE LAST HALF OF THE WORK WEEK AND FOR AT LEAST A PORTION OF THE
WEEKEND. A STRONG LOW AND COLD FRONT ARE EXPECTED TO REACH IDAHO SAT
NIGHT OR SUN MORNING. NEITHER THE FRONT TODAY NOR THE WEEKEND FRONT
SHOULD BRING MUCH RAINFALL. MAIN ISSUE WILL BE STRONG WIND WITH A
90 KNOT UPPER LEVEL JET OVERHEAD TODAY MIXING DOWNWARD IN THE
UNSTABLE AIR. MESSICK
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM MDT THIS
EVENING IDZ021.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1132 PM CDT MON SEP 16 2013
.UPDATE...
ISSUED AT 1130 PM CDT MON SEP 16 2013
MIDWEST DOPPLER RADARS WERE INDICATING AN AREA OF INCREASING
SHOWERS ALONG THE MO RIVER VALLEY FROM SE NEB/SW IA AND INTO EXTREME
NW MO LATE THIS EVENING. WARM AIR ADVECTION WAS KICKING IN AS THE
NOCTURNAL LOW LEVEL JET INTENSIFIES IN THE SOUTHERN PLAINS. ACROSS
THE DVN CWA THE CIRRUS SHIELD CONTINUED TO EXPAND NORTHEASTWARD AS
THE GREAT LAKES HIGH PRESSURE SYSTEM SLOWLY SHIFTS EAST. TEMPERATURES
HAVE ALREADY DIPPED INTO THE UPPER 40S IN NW IL WITH MID TO UPPER
50S COMMON ELSEWHERE.
THE 00Z SUBJECTIVE UPPER AIR ANALYSIS INDICATED A VERY DRY AIRMASS
FROM ABOUT THE MS RIVER VALLEY EASTWARD INTO THE GREAT LAKES. 850
MB DEWPOINTS WERE -10C AT KDVN...-18C AT KMPX...AND -23C AT KDTX.
WEST OF THE RIDGE AXIS COPIOUS MOISTURE WAS FOUND IN THE PLAINS.
850 MB DEWPOINTS WERE 14C AT KTOP AND IN THE RANGE OF 14 TO 17C
FROM SOUTHERN/WESTERN TX INTO OK. PRECIPITABLE WATERS WERE 150 TO
180 PERCENT OF NORMAL FOR MID SEPTEMBER IN THE PLAINS.
THE RAPID REFRESH/NAM THIS EVENING BRING IN A FEW LIGHT SHOWERS OR
SPRINKLES INTO OUR FAR SW CWA TOWARDS MORNING SO HAVE LEFT SMALL
POPS AS IS. HAVE ALREADY ADJUSTED SKY GRIDS BUT HAVE LEFT TEMPERATURES
ALONE FOR NOW.
UPDATE ISSUED AT 630 PM CDT MON SEP 16 2013
CIRRUS SHIELD CONTINUES TO SPILL INTO THE SOUTHWEST HALF OF THE
CWA BUT THINS AS IT RUNS INTO THE DRY AIR FARTHER TO THE NORTHEAST...
WITH HIGH PRESSURE SITUATED ACROSS THE GREAT LAKES REGION. WILL
MONITOR THIS EVENING THE TEMPERATURE AND CLOUD TRENDS AND ADJUST
IF NEEDED.
&&
.SYNOPSIS...
ISSUED AT 317 PM CDT MON SEP 16 2013
LATEST SFC ANALYSIS WAS INDICATING HIGH PRESSURE DOMINATING THE
WESTERN GRT LKS AND UPPER MS RVR VALLEY. SUBSIDENCE FROM THE HEART
OF THIS FEATURE AND UPPER LEVEL RIDGING HELPING ERODE STRATOCU
FIELDS IN THE CWA...BUT SOME CLOUD FIELDS HOLDING FIRM ACRS SOUTH
CENTRAL INTO SOUTHEASTERN IA. ALOFT...WATER VAPOR IMAGERY WAS
INDICATING LINGERING MONSOONAL MOISTURE FIELDS ACRS THE CENTRAL
PLAINS OVER TO THE OH RVR/TN VALLEY REGIONS...WHILE MOISTURE OFF
INGRID SURGES INLAND ACRS MEX/SOUTHERN TX. UPSTREAM WAVE NOTED
ACRS THE NORTHWEST PLAINS ON WESTERN FLANK OF UPPER RIDGE AXIS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 317 PM CDT MON SEP 16 2013
TONIGHT...WILL FOLLOW LATEST RAP LLVL MOISTURE/RH GUIDANCE WHICH
SUGGESTS A CONTINUED CLEARING OF THE STRATOCU EXCEPT MAYBE THE FAR
SOUTHWESTERN CWA THROUGH THIS EVENING. IT ALSO SUGGESTS LLVL FLOW
TO VEER TO THE EAST-SOUTHEAST OVERNIGHT AND POSSIBLY START ADVECTING
MORE HIGHER RH LEVELS/STRATOCU FROM SOUTHEAST IL/IND LATE TONIGHT
AFTER MIDNIGHT. FOR NOW WILL MAINTAIN MOSTLY CLR SKIES OVERNIGHT
FOR BULK OF THE EASTERN HALF OF THE CWA AND BANK ON COOL LOWS IN THE
40S WITH LOW/DRY AMBIENT SFC DPTS. BUT SOME BUST POTENTIAL ON THE LOW
SIDE IF THE CLOUDS DO ADVECT IN FROM THE EAST LATER TONIGHT ALONG
WITH HIGHER DPTS FROM THOSE SAME AREAS. WILL KEEP LOWS IN THE LOW TO
MID 50S IN THE SOUTHWEST THIRD WITH EXPECTED MID DECK/HIGHER CLOUD
INCREASE LATER TONIGHT FROM THE SOUTHWEST IN THOSE AREAS. ELEVATED
WARM AIR ADVECTION PROCESSES ASSOCIATED WITH RIDGE-RIDING WAVE
MENTIONED ABOVE PUSHING ACRS EASTERN NEB AND WESTERN IA TO TAP IN THE
LINGERING MONSOONAL MOISTURE AND PRODUCE SHOWERS OVERNIGHT...BUT
RIDGING AND DRY AIR IN PLACE TO MAKE FOR MOST OF THE CWA REMAINING
DRY THROUGH 12Z TUE. MUCH OF INITIAL LIFT FROM APPROACHING UPPER WAVE
TO GO INTO TOP-DOWN SATURATION PROCESSES WITH VIRGA TO LIGHT
SHOWERS/SPRINKLES ACRS THE SOUTHWEST THIRD TOWARD DAYBREAK.
TUESDAY...DESPITE SOME DECENT MODEL INDICATED ELEVATED THTA-E
ADVECTION AND CONVERGENT REGIONS PUSHING ACRS THE SOUTHWESTERN
THIRD TO HALF OF THE DVN CWA AS THE DAY PROGRESSES...THE BATTLE
WILL BE ON WITH LARGE DRY AIRMASS TO THE EAST. LIKE THE PREVIOUS
SHIFT MENTIONED...SHARP MOISTURE AND PRECIP GRADIENTS MAY DEVELOP
LOCALLY WITH SOME AREAS/IN THE FAR SOUTHWEST/ GETTING UP TO A
QUARTER INCH OF RAIN BY MID AFTERNOON...AND AREAS EAST OF THE MS RVR
ESPECIALLY EAST CENTRAL AND NORTHEAST REMAINING DRY THROUGH 00Z WED.
WILL SPREAD IN POPS GENERALLY FROM WEST-SOUTHWEST TO EAST IN
DECREASING FASHION TUE. BUT SOME AREAS PROBABLY WARRANT CATEGORICAL
POPS WEST OF THE MS RVR. EXPECT MAINLY SHOWERS IN DECLINING FASHION
AS THEY SPREAD EASTWARD AND ENCOUNTER THE DRY AIR...BUT PROGGED
MID LEVEL MUCAPES OF 200-500 J/KG IF CORRECT...SUPPORTS ISOLATED
EMBEDDED THUNDER IN THE SOUTHWESTERN HALF ON TUE. TEMPS WILL BE A
CHALLENGE TUE DEPENDING ON CLOUD COVER AND EVAPO-COOLING FROM
PRECIP. WILL GO WITH COOLER VALUES HELD DOWN IN THE 60S IN THE
WEST WITH EARLIER ARRIVAL OF CLOUDS AND PRECIP...WARMER IN THE LOW
70S EAST OF THE MS RVR. ..12..
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 317 PM CDT MON SEP 16 2013
ACTIVE WX WILL BE SEEN ACROSS THE MIDWEST FOR THE REMAINDER OF THE
WORK WEEK WITH SEVERAL CHANCES FOR RAIN.
RAIN THAT MOVES INTO THE AREA TUESDAY AFTERNOON WILL OVERSPREAD THE
AREA TUESDAY NIGHT/WED. AS THE OVERALL FORCING WEAKENS ON WEDNESDAY
THE AREAL COVERAGE OF PRECIPITATION WILL DECREASE WEDNESDAY
AFTERNOON.
WED NIGHT/THURSDAY THE NEXT ROUND OF FORCING MOVES THROUGH THE AREA
HELPING TO RE-DEVELOP NEW CONVECTION. A RESPECTABLE LLJ DEVELOPS WED
NIGHT WHICH SHOULD RESULT IN CONSIDERABLE NOCTURNAL CONVECTION AFTER
MIDNIGHT AND INTO THURSDAY MORNING.
THE APPROACHING COLD FRONT ON THURSDAY IS EXPECTED TO HELP MAINTAIN
CONVECTION DURING THE AFTERNOON. THE AMOUNT OF CLOUD COVER MAY HOLD
DOWN TEMPERATURES SOMEWHAT BUT THEY SHOULD STILL BE CLOSE TO NORMAL.
THURSDAY NIGHT ON...
THE MODEL CONSENSUS HAS HIGH CHC/LIKELY POPS FOR THURS NIGHT AS THE
NEXT FRONT MOVES THROUGH THE AREA. THE FRONT WILL CLEAR THE AREA ON
FRIDAY SO ONLY SCHC/LOW CHC POPS ARE GIVEN BY THE MODEL CONSENSUS
FOR THE EASTERN HALF OF THE CWFA.
COOL CANADIAN HIGH BUILDS INTO THE GREAT LAKES FOR FRIDAY NIGHT
THROUGH SUNDAY NIGHT. THE MODEL CONSENSUS GIVES DRY CONDITIONS WITH
TEMPERATURES AVERAGING BELOW NORMAL.
SOUTHERLY FLOW DEVELOPING ON MONDAY WILL ALLOW TEMPERATURES TO AGAIN
WARM. THE MODEL CONSENSUS HAS DRY CONDITIONS FOR MONDAY WITH CHC
POPS FOR MONDAY NIGHT. ..08..
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1130 PM CDT MON SEP 16 2013
VFR CONDS THROUGH MOST OF THIS TAF CYCLE. WILL SPREAD LIGHT RAIN
AND SPRINKLES TO KCID/KMLI/KBRL TUESDAY AFTERNOON BUT VSBYS SHOULD
REMAIN P6SM. EAST WINDS 5 TO 10 KNOTS TONIGHT THEN SOUTHEAST
AROUND 10 KNOTS TUESDAY AND TUESDAY EVENING. SHOWERS AND SCATTERED
THUNDERSTORMS WILL BEGIN TO INCREASE TUESDAY EVENING AS ELEVATED
INSTABILITY INCREASES WITH THE RETURN OF DEEPER MOISTURE. CIGS
SHOULD ALSO LOWER TO MVFR CATEGORY TUESDAY EVENING...ESPECIALLY
AT KCID/KBRL.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...HAASE
SYNOPSIS...12
SHORT TERM...12
LONG TERM...08
AVIATION...HAASE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1142 PM MDT MON SEP 16 2013
.UPDATE...
ISSUED AT 637 PM MDT MON SEP 16 2013
JUST COMPLETED AN EXTENSIVE UPDATE. MODELS PLAYING CATCHUP. SINCE
IT DID NOT CLEAR OFF...TEMPERATURES ARE STARTING OUT MUCH COOLER
THAN WHAT THE MODELS THINK. FOG HAS ALREADY DEVELOPED AND EXPECT
IT TO CONTINUE AS LOW LEVEL WIND FIELD WILL CONTINUE TO ADVECT IN
HIGHER DEWPOINTS. SO THROUGH TOMORROW MORNING HAVE INTRODUCED
WIDESPREAD FOG AND DRIZZLE. THE RUC IS CATCHING THIS THE BEST
RIGHT NOW WITH THE NAM/ECMWF NOT TOO FAR BEHIND.
CONSEQUENTLY ADJUSTED THE CLOUD COVER AND THE WIND FIELD...WHICH
THE RUC IS DOING THE BEST ON...AS WELL. ALSO CURRENT TEMPERATURES
WERE NEAR OR BELOW THE FORECAST MINS SO LOWERED THOSE ACCORDINGLY.
THE OTHER MAIN CHANGE WAS THE PRECIPITATION FORECAST. RIGHT NOW NOTHING
GOING ON...SO REMOVED THUNDERSTORMS THROUGH MID EVENING...AS ANOTHER
SHORTWAVE TROUGH MOVES IN FROM THE WEST. AT THE SAME TIME A RATHER
STRONG 700 MB WARM AIR ADVECTION DEVELOPS AS A WEAK RIGHT REAR
QUADRANT OF 250 MB JET AFFECTS THE AREA AS WELL.
THESE ALL COME TOGETHER AND INCREASE IN STRENGTH AS THE NIGHT GOES
ON. THETA-E LAPSE RATES ARE VERY FAVORABLE FOR RESPONSE TO THE
LIFT. ELEVATED CAPE INCREASES AS ELEVATED CINH DECREASES. RIGHT
NOW THE BEST CHANCE FOR THUNDERSTORMS WILL BE AFTER 06Z AND IN THE
EASTERN HALF. WOULD NOT BE SURPRISED IF THUNDERSTORMS BECOME RATHER
STRONG CONSIDERING THE AMOUNT OF CAPE AND THE VERY FAVORABLE LAPSE
RATES.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 1148 AM MDT MON SEP 16 2013
A COOL HIGH PRESSURE AREA REMAINS IN PLACE OVER THE FORECAST AREA
TODAY AS A FEW LIGHT TO MODERATE SHOWERS MOVE NORTHEASTWARD ACROSS
THE EASTERN SECTIONS OF THE FORECAST AREA. THESE SHOWERS ARE A
RESULT OF A COUPLE OF SHORT WAVE TROUGHS IN THE UPPER FLOW MOVING
EAST OF THE ROCKIES AND ACROSS THE CENTRAL HIGH PLAINS REGION THIS
AFTERNOON AND EVENING. EXPECT A FEW MORE SHOWERS TO DEVELOP AS A
SECOND WEAKER SHORT WAVE TROUGH FOLLOWS IN ITS PATH. BEHIND THOSE
WAVES A WEAK RIDGE AND MORE WESTERLY FLOW MOVES EAST OF THE
ROCKIES WITH AN AREA OF SUBSIDENCE ACROSS THE FORECAST AREA ON
TUESDAY AND A LEE TROUGH THAT DEEPENS ALONG THE FRONT RANGE OF
WYOMING AND COLORADO. AS THIS TROUGH DEEPENS...THE HIGH PRESSURE
AREA MOVES EAST AND THE MOIST RETURN FLOW BEGINS TO MOVE OUT OF
THE REGION TO BE REPLACED BY A DRYER SOUTH TO SOUTHWEST NEAR
SURFACE FLOW. LOW CLOUDS AND FOG THAT ARE EXPECTED TO DEVELOP
IN THE SATURATED AIR MASS ACROSS THE AREA OVERNIGHT ARE EXPECTED TO
DIMINISH BY LATE TUESDAY AFTERNOON AND EVENING WITH A RETURN OF
HIGH TEMPERATURES IN THE 80S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 219 PM MDT MON SEP 16 2013
A SHORTWAVE RIDGE WILL BE OVER THE PLAINS TUESDAY NIGHT FOLLOWED BY
WESTERLY FLOW THROUGH THURSDAY AS A TROUGH MOVES ACROSS THE NORTHERN
PLAINS. A SURFACE TROUGH WILL EXTEND SOUTH INTO EASTERN COLORADO
TUESDAY NIGHT/WEDNESDAY. THIS TROUGH WILL MOVE SOUTHEAST INTO
NORTHWEST KANSAS WEDNESDAY NIGHT. HIGH PRESSURE WILL MOVE INTO
NORTHWEST KANSAS THURSDAY.
CONDITIONS WILL REMAIN DRY TUESDAY NIGHT AND WEDNESDAY DUE TO
SUBSIDENCE OVER THE AREA. SOME DYNAMICS MOVE INTO THE AREA WEDNESDAY
NIGHT BUT MOISTURE IS NOT IMPRESSIVE SO WILL CONTINUE SLIGHT CHANCE
POPS FOR THUNDERSTORMS. DYNAMICS STILL REMAIN OVER THE FA EAST OF
THE COLORADO BORDER THURSDAY MORNING AND SHIFT EAST SOME THURSDAY
AFTERNOON BEFORE MOVING OUT OF THE AREA. ONCE AGAIN, H8-7 LAYER
MEAN RH IS LACKING SO WILL CONTINUE SLIGHT CHANCE POPS.
850MB TEMPERATURES SUPPORT MAX TEMPERATURES REACHING THE UPPER
80S/LOWER 90S WEDNESDAY. MAX TEMPERATURES SHOULD COOL TO THE 70S
THURSDAY BEHIND THE TROUGH. MIN TEMPERATURES TUESDAY NIGHT WILL BE
IN THE UPPER 50S/LOWER 60S COOLING TO THE MID 50S TO LOWER 60S
WEDNESDAY NIGHT.
IN THE EXTENDED...(THURSDAY NIGHT THROUGH MONDAY)...THIS PART OF THE
FORECAST WILL BE DRY THROUGH SATURDAY NIGHT WITH A RIDGE AND
SUBSIDENCE OVER THE REGION. THE RIDGE SHIFTS EAST SUNDAY ALLOWING A
TROUGH TO MOVE EAST INTO THE AREA. SLIGHT CHANCE TO CHANCE POPS ARE
SUPPORTED WITH NIL POPS FOR MONDAY
MAX TEMPERATURES WILL WARM UP INTO THE 80S UNDERNEATH THE INFLUENCE
OF THE RIDGE AND THEN COOL TO THE MID AND UPPER 70S MONDAY BEHIND
THE EXITING SHORTWAVE. MIN TEMPERATURES WILL RESIDE IN THE LOWER TO
MID 50S THURSDAY AND FRIDAY NIGHTS MODERATING TO THE MID/UPPER 50S
SATURDAY/SUNDAY NIGHTS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1140 PM MDT MON SEP 16 2013
IFR TO LIFR CONDITIONS ARE EXPECTED AT BOTH SITES THROUGH THE
MORNING HOURS. AT KMCK...THERE IS ENOUGH OF A CHANCE TO HAVE A
THUNDERSTORM AFFECT THE SITE THAT DID INCLUDE A VCTS MENTION FROM
09Z TO 12Z. BY LATE MORNING TO EARLY AFTERNOON CONDITIONS WILL
IMPROVE FROM MVFR TO VFR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...LOCKHART
LONG TERM...FS
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
509 AM EDT TUE SEP 17 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 508 AM EDT TUE SEP 17 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM
IL/WI INTO NW ONTARIO. AT THE SFC...A RIDGE WAS LOCATED OVER THE ERN
GREAT LAKES RESULTING IN SRLY THROUGH THE UPPER MS VALLEY INTO THE
WRN CWA. THE COMBINATION OF WAA AND A WEAK UPSTREAM SHORTWAVE TROUGH
OVER IA SUPPORTED AN AREA OF LIGHT SHOWERS FROM ERN NEB INTO NW IA.
OTHERWISE...IR LOOP INDICATED CLEAR SKIES OVER THE NRN GREAT LAKES.
TODAY...HIGH PRES AND THE LINGERING DRY AIRMASS WILL CONTINUE TO
DOMINATE THE WEATHER WITH MOSTLY SUNNY SKIES OVER UPPER MI. MIXING
TO AROUND 900-875 MB (AROUND 11C) WILL RESULT IN MAX READINGS IN THE
MID TO UPPER 60S.
TONIGHT...MDLS SUGGEST THAT AS THE IA SHRTWV GRADUALLY LIFTS TO THE
NORTHEAST...MOISTURE WILL INCREASE AND SOME LIGHT WAA PCPN WITH AREA
OF 300K-310K ISENTROPIC LIFT WILL SPREAD FROM SE MN AND WRN WI
TOWARD UPPER MI. THE NAM/GFS WERE A BIT MORE AGGRESSIVE IN BRINGING
SOME LIGHT PCPN INTO THE CWA COMPARED TO THE GEM/ECMWF. GIVEN THE
VERY DRY ANTECEDENT AIRMASS...THE FCST LEANS MORE TOWARD THE SLOWER
ONSET OF PCPN WITH ONLY A SLIGHT CHANCE OF LIGHT SHOWERS TOWARD 12Z
NEAR THE WI BORDER.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 447 AM EDT TUE SEP 17 2013
WED THROUGH MOST OF THU...A LOW PRESSURE SYSTEM CURRENTLY OFF THE
PACIFIC NW CONUS WILL DEEPEN WHILE MOVING FROM MT AT 12Z WED TO THE
CENTRAL SASKATCHEWAN/ONTARIO BORDER BY 00Z FRI. WILL DISCUSS PRECIP
ALONG THE COLD FRONT THAT MOVES IN LATE THU MOMENTARILY...BUT BEFORE
THAT MOVES IN EXPECT JUST SOME MINOR PRECIP. BEST CHANCE FOR PRECIP
LOOKS TO BE WITH BROAD WAA AHEAD OF THE SYSTEM...SO SOME LIGHT
PRECIP IS DIFFICULT TO FORECAST. HOWEVER...AGREE WITH PREVIOUS SHIFT
THAT SLIGHT CHANCE TO LOW CHANCE POPS SEEM WARRANTED PRIOR TO COLD
FROPA. HIGHS WED LOOK TO BE AROUND 70 WITH 850MB TEMPS OF 10-14C.
THU TEMPS LOOKS MORE CONDITIONAL AS LOW CLOUDS MAY INHIBIT MIXING OF
14-19C 850MB TEMPS...BUT COULD SEE HIGHS IN THE MID 70S IF ENOUGH
CLEARING OCCURS.
NOW FOR THE PROMISED DISCUSSION OF PRECIP ALONG THE COLD FRONT. THE
LOW WILL CONTINUE DEEPENING AS IT MOVES TO HUDSON BAY BY 00Z
SAT...THEN REMAINS NEARLY STATIONARY WHILE OCCLUDING THROUGH THE
REST OF SAT. WHILE DISCUSSING THE TRACK/TIMING OF THE SYSTEM...LET
IT BE SAID THAT MODELS ARE DOING MUCH BETTER THAN 24 HOURS
AGO...BOTH WITH RUN TO RUN CONTINUITY AND WITH MODEL TO MODEL
AGREEMENT. STILL THINK THERE WILL BE SHIFTS IN THE TRACK/TIMING BY
THE MODELS OVER THE NEXT FEW RUNS...BUT SHOULD AT LEAST BE GETTING A
BETTER IDEA OF WHAT THE SYSTEM WILL DO. THE COLD FRONT TIMING IS
ALSO SIMILAR BETWEEN MODEL RUNS...AT LEAST RELATIVELY SO FOR THIS
TYPE OF SYSTEM...WITH THE FRONT MOVING INTO THE FAR WRN CWA AROUND
00Z FRI...THEN TO THE CENTRAL CWA AROUND 12Z FRI AND TO THE ERN CWA
BY 18Z FRI. EXPECT A LINE OF SHOWERS AND THUNDERSTORMS TO MOVE
ACROSS THE CWA MAINLY THU NIGHT...AND AGREE WITH PREVIOUS SHIFT THAT
LIKELY POPS ARE JUSTIFIED. DRY SLOT MOVES IN BEHIND THE
FRONT...WHICH SHOULD BRING AN END TO SYNOPTIC PRECIP AS THE
MID/UPPER LEVELS DRY OUT. HOWEVER...WRAP AROUND MOISTURE WILL STILL
BE PRESENT IN THE LOW LEVELS AS THE UPPER TROUGH MOVES OVERHEAD FRI
INTO FRI NIGHT WITH 850MB TEMPS AS LOW AS 1C THROUGH 00Z FRI AND AS
LOW AS -2C FRI NIGHT. WLY LOW LEVEL WINDS MEANS THE W WIND LAKE
EFFECT/UPSLOPE BELTS WILL SEE THE BEST CHANCES FOR RAIN BEHIND THE
FRONT FRI AND FRI NIGHT.
MODELS DO START TO VARY MORE WITH HOW LONG TO LINGER THE UPPER
TROUGH OVER THE AREA SAT AND HOW QUICK TO BRING IN AN UPPER RIDGE
FROM THE W. THE GFS IS SLOWER WITH THE TROUGH AND HAS 850MB TEMPS
AROUND -2C AT 00Z SUN WHILE THE ECMWF HAS 850MB TEMPS OF 2-8C AT THE
SAME TIME. THEREFORE...HAVE LITTLE CONFIDENCE IN TEMPS FOR SAT. WITH
SUCH A SPREAD IN LOW LEVEL TEMPS...THERE IS ALSO A SPREAD IN
POSSIBILITIES FOR LAKE EFFECT RAIN...SO WILL CONTINUE TO HAVE SLIGHT
CHANCE IN THE FORECAST.
SUN SHOULD SEE A WARM UP AS THE UPPER RIDGE MOVES OVERHEAD...BUT
STILL NOT VERY CONFIDENT ON EXACT TEMPS FOR THE DAY GIVEN CONTINUED
MODEL SPREAD...BUT AT LEAST SHOULD BE WARMER AND DRIER THAN SAT.
MON SHOULD AGAIN SEE WARMING TEMPS AS SLY FLOW INCREASES AHEAD OF
THE NEXT LOW PRESSURE SYSTEM DEVELOPING OVER THE PLAINS. .
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 129 AM EDT TUE SEP 17 2013
WITH DRY HI PRES DOMINATING...VFR CONDITIONS WL BE THE RULE THIS
FCST PERIOD AT ALL 3 TAF SITES. AS THE HI DRIFTS FARTHER E AND A
STRONGER PRES GRADIENT TAKES SHAPE OVER THE UPR LKS...EXPECT A GUSTY
S WIND TO DVLP BY THIS AFTN IN THE PRESENCE OF DAYTIME HEATING/
MIXING. LLWS WL RESULT TNGT WITH NOCTURNAL COOLING CAUSING A
RADIATION INVRN AND DECOUPLING OF A LIGHTER SFC FLOW FM THE STRONGER
WINDS ABV THE INVRN.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EDT TUE SEP 17 2013
AS THE HIGH SHIFTS TO THE EAST...SRLY WINDS UP TO 20 KNOTS ARE
EXPECTED FROM TODAY INTO WED. WINDS SHOULD THEN REMAIN BELOW 20
KNOTS UNTIL FRI WHEN A COLD FRONT MOVES THROUGH THE REGION AND
BRINGS W TO NW WINDS UP TO 30 KNOTS FRI INTO SAT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FROST ADVISORY UNTIL 9 AM EDT /8 AM CDT/ THIS MORNING FOR MIZ002-
004>007-009>014-084-085.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
325 AM CDT Tue Sep 17 2013
.SHORT TERM: (Through Late This Afternoon)
Issued at 303 AM CDT Tue Sep 17 2013
Synoptic pattern over the region today will be dominated by broad
WAA overrunning the cooler Canadian airmass that backed into the
area Monday and overnight, which should certainly generate showers
and a few thunderstorms today in the northwest half of the CWA.
However, other than lead shortwave responsible for the light echoes
in se MO attm (which is outrunning better moisture) and some 850mb
theta-e advection vaguely focused over our n counties this morning,
mechanisms for precip are rather ill-defined. The lack of a
well-defined precip structure in the early morning regional radar
imagery is indicating the rather diffuse nature of the lift.
Plan to maintain broad PoP trends in current forecast with likely
POPS in our northwest counties to chance PoPs in se MO, although
specific numbers in a few locations will be changing to reflect
latest radar trends. In our e counties couldn`t rule out a few
sprinkles early today, but chances of measurable precip here look
low attm. Will make a last minute call on this.
Other concern for today is how warm to go on high temperatures, as
residual cool air and scattered showers will at least partially
offset warming due to the WAA. Still working on specifics but most
areas should remain in the 70s, with the coolest temps over the
northwest counties where clouds will be thickest and threat of
showers should be highest.
Truett
.LONG TERM: (Tonight through Monday)
Issued at 303 AM CDT Tue Sep 17 2013
Isolated to scattered SHRA/TSRA may continue percolating tonight due
to isentropic ascent along the 300-305 K surface, with the highest
precip chances across northeast MO and west central IL. Once the
second of two shortwaves (which were located over KS and OK early
this morning) and a warm front finally lift northeastward tonight,
precipitation should also lift away from the area.
Early morning water vapor imagery along and recent RUC 1.5 PVU
analyses depicted a strong vort max located just off the northern
CA coast. This feature is forecast to cross the Rockies and induce
surface cyclogenesis over SD/ND tomorrow, although it will also
influence conditions over MO/IL by producing weakly diffluent
southwesterly flow aloft. Between general moistening of the air
mass (PW values rise to around 1.7 inches by Wed night),
increasing H7-H5 lapse rates, and nocturnal LLJ activity, it`s
hard to rule out disorganized iso-sct precip for Wed and Wed
night, particularly across the northern and northeastern CWA. In
terms of the aforementioned low pressure system which will be
moving along the US/Canadian border and into southern Canada by
Thu night, models remain in general agreement with the overall
pattern despite some differences after 20/00z regarding a piece of
energy that breaks off near the base of the trough and then moves
across MO on Fri night. The cold front is forecast to approach the
CWA on Thu night and then move through on Fri/Fri night. Low level
convergence with the front, large scale ascent ahead of the upper
level trough axis, and favorable positioning beneath the right
entrance region of a jet at H25 all support likely PoPs for Thu
night and Fri across parts of the CWA. Precipitation is expected
to end from northwest to southeast due to post-frontal subsidence.
17/00z runs of the ECMWF/GFS/GEM all agree that a surface high
pressure center will build into the Great Lakes this weekend and
that there will be some degree of upper ridging over the Plains
ahead of the next progressive trough near the West Coast, but each
model has a different take on the upper level pattern east of the
Mississippi River with potential impacts for the MO/IL forecast.
The GFS depicts a closed low over the OH valley, the GEM brings a
tropical low northward from the Gulf of Mexico, and the ECMWF has
a weak upper trough axis oriented from LA through GA and into VA.
Since there is little confidence in any particular solution at
this time, the forecast grids for Sat-Mon generally reflect the
recommended CR initialization.
Kanofsky
&&
.AVIATION: (For the 06z TAFs through 06z Tuesday Night)
Issued at 1154 PM CDT Mon Sep 16 2013
Mid and high clouds persist over area with mvfr cigs just west
and southwest of forecast area as of 0430z. Will see the mvfr cigs
slowly make their way to the northeast towards taf sites. Taf
sites along I-70 corridor to see cigs lower to mvfr between 08z-
11z Tuesday. Otherwise, trying to figure out timing and coverage
of showers and possibly a few thunderstorms. Activity over eastern
KS, western MO to continue to develop and slide east, reaching
central MO by 14z and west central IL by 19z. For now just kept
vcnty shower mention. Not sure it will hold together and reach STL
metro area, so kept those tafs dry for now. MVFR cigs to lift and
scatter out by midday. As for winds, east winds to veer over time
to the southeast, then eventually to the south as surface ridge
moves off to the east.
Specifics for KSTL:
Mid and high clouds persist over area with mvfr cigs just west
and southwest of forecast area as of 0430z. Will see the mvfr cigs
slowly make their way to the northeast towards metro area. Cigs
to lower to mvfr by 11z Tuesday. Otherwise, trying to figure out
timing and coverage of showers and possibly a few thunderstorms.
Activity over eastern KS, western MO to continue to develop and
slide east. Not sure it will hold together and reach STL metro
area, so kept KSTL dry for now. MVFR cigs to lift and scatter out
by 16z Tuesday. As for winds, east winds to veer to the
south by 16z Tuesday as surface ridge moves off to the east.
Byrd
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
414 AM CDT TUE SEP 17 2013
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 414 AM CDT TUE SEP 17 2013
CHALLENGES INCLUDE CLOUD COVER AND TEMPERATURES TODAY/TONIGHT AND
THEN PRECIPITATION CHANCES/SEVERE POTENTIAL WEDNESDAY NIGHT INTO
THURSDAY. GFS/NAM/ECMWF/GEM IN GOOD OVERALL AGREEMENT AND WILL
USE A BLENDED SOLUTION FOR THIS FORECAST PACKAGE.
FOR TODAY...MOIST SOUTHERLY FLOW BETWEEN THE SURFACE HIGH ACROSS
THE GREAT LAKES AND DEVELOPING LOW IN THE LEE OF THE NORTHERN ROCKIES
WILL ADVECT LOW CLOUDS CURRENTLY ACROSS EASTERN SD/SOUTHERN MN/
NE/IA NORTHWARD ACROSS THE FORECAST AREA. RAP 925 HPA RH SUGGESTS
THESE CLOUDS WILL MOVE INTO THE SOUTHERN FORECAST AREA BY 12 UTC
AND THEN ALONG AND EAST OF THE VALLEY BY THIS AFTERNOON. AREAS
WITH PERSISTENT CLOUD COVER NOT LIKELY TO RISE ABOVE 70 DEGREES.
LOWER TO MID 70S ARE POSSIBLE ACROSS THE DEVILS LAKE BASIN AND
NORTHERN VALLEY WHERE MORE SUNSHINE IS EXPECTED. TODAY WILL ALSO
BE BREEZY TO LOCALLY WINDY WITH 30 KTS IN THE MIXED LAYER. THIS
SHOULD TRANSLATE TO SURFACE WINDS FROM 15 TO 25 MPH WITH GUSTS UP
TO 30 MPH.
LOW CLOUDS WILL BE VERY SLOW TO DISSIPATE OVERNIGHT...ESPECIALLY
ACROSS THE EASTERN FORECAST AREA. MODEL SOUNDINGS SUGGEST THE
POSSIBILITY OF SOME LIGHT DRIZZLE...BUT GIVEN LOW SENSIBLE WEATHER
IMPACT AND COVERAGE UNCERTAINTY...WILL NOT INCLUDE IN CURRENT
GRIDS. SOUTHERLY WINDS WILL REMAIN ELEVATED BETWEEN 10 AND 15
MPH WITH LOW TEMPERATURES GENERALLY IN THE 50S.
STRONG POSITIVE THERMAL ADVECTION IN THE WARM SECTOR OF AN
APPROACHING PACIFIC WAVE WILL RESULT IN TEMPERATURES WELL ABOVE
NORMAL ON WEDNESDAY. AFTERNOON HIGHS WILL CLIMB INTO THE MID 70S
TO LOWER 80S. SOUTHERLY WIND WILL NOT BE AS STRONG AS TODAY. MOST
OF THE DAY SHOULD BE DRY WITH ONLY A CHANCE FOR AFTERNOON SHOWERS
AND THUNDERSTORMS ACROSS THE DEVILS LAKE BASIN.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 414 AM CDT TUE SEP 17 2013
A STRONG SURFACE LOW WILL TRACK ACROSS ND WEDNESDAY EVENING AND
INTO THE CENTRAL/NORTHERN VALLEY BY 06 UTC THURSDAY. WARM
TEMPERATURES ALOFT MAY LIMIT CONVECTIVE INITIATION...BUT THE
COMBINATION OF MLCAPE UP TO 2000 J/KG...PWATS AROUND 1.5 INCHES...
AN APPROACHING SURFACE COLD FRONT AND INCREASING BULK SHEAR FROM A
300 HPA JET STREAK SHOULD RESULT IN THUNDERSTORM DEVELOPMENT
ACROSS EASTERN ND INTO NORTHWEST MN. SOME STORMS NEAREST TO THE
SURFACE LOW MAY BECOME SEVERE AND THIS IS HIGHLIGHTED IN THE SPC
DAY 2 CONVECTIVE OUTLOOK WHICH SHOWS A SLIGHT RISK ALONG AND
NORTHWEST OF A LINE FROM CARRINGTON TO GRAND FORKS TO HALLOCK.
TOO EARLY TO ADD SEVERE WORDING TO THE GRIDS...BUT SOMETHING TO
WATCH.
WITH THE EXCEPTION OF SOME WRAP-AROUND SHOWERS LATE WEDNESDAY
NIGHT INTO THURSDAY ACROSS THE NORTHERN FORECAST AREA...MOST OF
EASTERN ND/NORTHWEST MN WILL BE DRY-SLOTTED ONCE CONVECTION MOVES
INTO CENTRAL AND EAST CENTRAL MN BY 12 UTC THURSDAY. STRONG
WESTERLY WINDS WILL FOLLOW IN THE WAKE OF THE SURFACE FRONT...
ALONG WITH A MUCH COOLER AIR MASS. HIGH TEMPERATURES THURSDAY WILL
RANGE FROM THE LOW 60S ACROSS THE DEVILS LAKE BASIN TO THE LOW 70S
ACROSS WEST CENTRAL MN LAKES COUNTRY. WEST WINDS WILL RANGE FROM
15 TO 25 MPH.
FRIDAY THROUGH MONDAY...THE WEEK WILL END QUIET AND COOL WITH
NORTHWESTERLY FLOW BEHIND THE DEPARTING TROUGH AND HIGH PRESSURE
BUILDING INTO THE PLAINS. A FEW SHOWERS MAY LINGER OVER LAKE OF THE
WOODS AREA BUT OTHERWISE THINK WE WILL BE DRY THROUGH FRIDAY AND
INTO SATURDAY. THE WEEKEND WILL SEE A SLOW WARMING TREND AS
SOUTHERLY WINDS RETURN. THE MAIN UPPER TROUGH WILL REMAIN OVER THE
WESTERN CONUS THROUGH THE END OF THE PERIOD BUT MODELS ALL SHOW
SIGNS OF A LEAD SHORTWAVE MOVING FROM THE NORTHERN ROCKIES THROUGH
THE PLAINS LATE SUNDAY AND INTO MONDAY. KEPT FAIRLY HIGH POPS GOING
FOR SUNDAY NIGHT AND MONDAY AS A WEAK SFC TROUGH AXIS/FRONTAL
BOUNDARY MOVES THROUGH. TEMPS WILL BE A FEW DEGREES LOWER ON MONDAY
BUT STILL AROUND SEASONAL AVERAGES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1110 PM CDT MON SEP 16 2013
THE MVFR CLOUDS IN SOUTHERN SD SHOULD SLOWLY ADVECT TO THE NORTH
AND EAST OVERNIGHT. HAVE MENTIONED SOME MVFR CIGS INTO FAR/BJI LATE
TONIGHT INTO TUE MORNING. THESE CLOUDS COULD AFFECT AREAS A BIT
FURTHER NORTH AS WELL...BUT FOR NOW HAVE KEPT ANY CIGS IN THE VFR
RANGE. THERE COULD BE RE-DEVELOPMENT OF CIGS TUE NIGHT AFTER 00Z
WED...AND HAVE MENTIONED THIS AS WELL. WINDS COULD GUST OVER 25KT
IN MOST AREAS BY LATE TUE MORNING AND CONTINUE THROUGH AFTERNOON...
WITH 25-40KT IN THE MIXED LAYER THROUGH TUE MORNING. CAN/T RULE OUT
SOME LOW LEVEL WIND SHEAR LATE TONIGHT IF DE-COUPLING IS STRONGER
THAN FORECAST...WITH 40KT AT TIMES NEAR 925MB IN THE 06-12Z TIME
RANGE. WILL NOT MENTION LLWS IN THE TAF WITH LIMITED CONFIDENCE...BUT
SOMETHING TO KEEP IN MIND.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...ROGERS
LONG TERM...ROGERS/JR
AVIATION...DK
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1113 PM CDT MON SEP 16 2013
.DISCUSSION...
See aviation discussion below...
&&
.AVIATION...
Showers continue near KBBD, and these may persist into the early
morning hours, which is reflected in TAF package. Isolated showers
or thunderstorms will be possible elsewhere overnight, but coverage
should remain isolated enough to preclude a mention in the TAFs.
Patchy stratus may develop at KJCT and KSOA around daybreak, but at
this time I think ceilings will remain VFR. Otherwise, VFR
conditions are expected to prevail with light winds.
&&
.PREV DISCUSSION... /ISSUED 942 PM CDT MON SEP 16 2013/
UPDATE...
Increased POPS sightly across southern sections overnight.
DISCUSSION...
Convection has diminished considerably across the Big Country this
evening with only some light showers remaining. Meanwhile, a new
area of showers and a few thunderstorms are developing across
southeast counties with additional development farther southeast
across the Hill Country. Most of the models are of little help this
evening but the RUC does show an increase in activity along the
I-10 corridor by early morning. Given the latest convective trends,
have increased POPS to 40 percent across the south and will maintain
20 to 30 percent elsewhere for the overnight period. The rest of
the forecast looks on track with no other changes needed at this
time.
PREV DISCUSSION... /ISSUED 613 PM CDT MON SEP 16 2013/
DISCUSSION...
See aviation discussion below...
AVIATION...
Scattered showers and thunderstorms have decreased across much of
West Central Texas during the last hour or so. I still expect
isolated showers and thunderstorms through at least 02z, and this is
reflected in the TAFs. A couple of outflow boundaries are moving
toward KSJT, and this could result in brief gusty variable winds.
Isolated to scattered showers and thunderstorms will be possible on
Tuesday, but I have left any mention out of the TAF package due to
low confidence. Overall, expect VFR conditions to prevail through
the next 24 hours.
PREV DISCUSSION... /ISSUED 409 PM CDT MON SEP 16 2013/
SHORT TERM...
(Tonight and Tuesday)
Upper level high pressure is currently resting across much of Texas
and east into the Gulf of Mexico. This high pressure will be fixed
through Tuesday evening, setting up south southeasterly flow across
the area. This will assist in funneling moisture from Tropical
Storm Ingrid and the remnants of Manuel into West Central Texas.
With this flow pattern we expect the best chances of rainfall across
our southwestern counties. We expect theses showers and
thunderstorms to be diurnally driven, given the lack of capping and
upper level support.
Adjusted the overnight lows into the upper 60s and near 70 to
account for the influx of moisture and expected cloud cover.
Afternoon highs will be near normal with temperatures in the upper
80s to near 90.
18
LONG TERM...
(Tuesday Night through Monday)
Rain Chances Increase with Locally Heavy Rainfall Possible...
The main forecast focus revolves around rain chances Wednesday-
Friday, and the possibility of locally heavy rainfall. There is
also potential for greater coverage of rainfall across our area.
The upper high will shift a bit east and by Wednesday become
centered over the northern Gulf of Mexico. Our area will be on its
western periphery. The 12Z GFS and ECMWF show an upper reflection
from the remnants of Ingrid moving north out of Mexico and into
West Texas on Wednesday, followed by another upper level
disturbance (possible remnants of tropical system near the western
coast of Mexico) moving north- northeast into West Central Texas
by Thursday morning. We have low POPs at this time Wednesday and
Wednesday night, increasing Thursday. These may need to be raised
substantially if subsequent model runs remain consistent. Locally
heavy rainfall will be possible, with precipitable water values
increasing to between 1.5 and 2 inches.
On Friday, an upper trough moving into the Midwest will send a cold
front south into Texas, with the front progged to sag south into
West Central Texas. With a moist airmass remaining in place, could
have additional showers and thunderstorms across our area.
Carrying chance POPs Friday and these also may need to be increased.
Drier conditions are indicated for our area next weekend with upper
shortwave ridge building back into Texas.
19
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 71 89 70 92 71 / 20 20 10 10 10
San Angelo 70 88 69 92 71 / 30 30 10 10 20
Junction 70 87 69 91 70 / 40 30 10 10 20
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
Daniels
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1020 AM EDT TUE SEP 17 2013
.SHORT TERM (TODAY-THURSDAY)...
14Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN UPPER LEVEL PATTERN
THAT IS HIGHLY AMPLIFIED TO THE NORTH THROUGH THE MIDDLE SECTION OF
THE COUNTRY FOR THE MIDDLE OF SEPTEMBER. THIS LARGE RIDGE SITS
BETWEEN TWO SHARP TROUGHS ALONG BOTH THE PACIFIC AND ATLANTIC
SEABOARDS. THE FLORIDA PENINSULA RESIDES UNDER A WEAK UPPER LEVEL
PATTERN ON THE EASTERN PERIPHERY OF ELONGATED UPPER RIDGING ALONG
THE NORTHERN GULF COAST.
12Z KTBW SOUNDING PROFILE IS RATHER MOIST WITH A PW VALUE
APPROACHING 2". HOWEVER...LAPSE RATE...ESPECIALLY IN THE MID-LEVELS
/ HAIL GROWTH ZONE ARE NOT IMPRESSIVE. THE MOIST ATMOSPHERE AND
EASTERLY LOW LEVEL FLOW REGIME SUGGEST WE WILL STILL HAVE AN ACTIVE
CONVECTIVE AFTERNOON/EARLY EVENING...ESPECIALLY FROM I-4
SOUTHWARD...BUT MUCH ROBUST CONVECTION WITH SEVERE SUPPORTIVE
UPDRAFTS APPEARS UNLIKELY. ISOLATED CONVECTIVE CELL CAN ALWAYS
SURPRISE YOU IF IT FINDS A LOCAL REGION OF GOOD LOW LEVEL
FOCUS...BUT OVERALL A MORE MODERATED DAY OF CONVECTIVE STRENGTH
SEEMS LIKELY.
HAVE SEEN SOME SHOWERS/STORMS ALONG THE FLORIDA EAST COAST WITHIN
THE ZONE OF EASTERLY SPEED CONVERGENCE. AS WOULD BE EXPECTED...THIS
ACTIVITY DISSIPATES QUICKLY AS IT TRIES TO MOVE INLAND AND AWAY FROM
THIS NARROW FOCUS ZONE. WITH THIS IN MIND...SHOULD HAVE A FEW MORE
HOURS OF GENERALLY DRY CONDITIONS ACROSS OUR FORECAST AREA BEFORE
DIURNAL HEATING AND RESIDUAL OUTFLOW BOUNDARIES START THE EARLY
AFTERNOON CONVECTIVE PROCESS.
BASED ON LATEST HI-RES CONVECTIVE ALLOWING GUIDANCE SUITE...CURRENT
LATE DAY RAIN CHANCES OF 25-40% NORTH OF I-4 AND 50-60% FURTHER
SOUTH STILL APPEAR ON TRACK. THE DEEPEST MOISTURE IS CERTAINLY OVER
THE SOUTHERN 2/3RDS OF THE FORECAST AREA THIS AFTERNOON AND IS
LIKELY WHAT THE GUIDANCE IS PICKING UP ON TO SUPPORT THE GREATER
CONVECTIVE COVERAGE FROM TAMPA BAY SOUTHWARD.
TONIGHT...
SHOWERS AND STORMS PUSH OFFSHORE DURING THE EVENING HOURS...AND THE
PATTERN SUGGEST WE WILL LIKELY SEE AT LEAST SOME CONVECTIVE COVERAGE
OVER THE SOUTHERN COASTAL WATERS WELL INTO THE OVERNIGHT. HIGH
PRESSURE BUILDING DOWN THE EASTERN SEABOARD FROM THE MID-ATLANTIC
STATES WILL ALSO SET UP A GOOD SYNOPTIC PATTERN TO SUPPORT A
NOCTURNAL EASTERLY WIND SURGE OVER THE COASTAL WATERS. THIS SURGE IS
FORECAST TO REACH CAUTIONARY LEVELS...SHOULD BEGIN SHORTLY AFTER
SUNSET...AND BE MOST NOTABLE THE FURTHER NORTH FROM ENGLEWOOD ONE
TRAVELS.
&&
.AVIATION...
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT ALL TERMINALS THIS MORNING
INTO THE EARLY AFTERNOON HOURS. SCATTERED SHRA/TSRA SHOULD DEVELOP
EARLY AFTERNOON...SO WILL CURRENTLY KEEP VCTS AT 18Z FOR SOUTHERN
AIRPORTS AND 19Z FROM SRQ NORTHWARD. WILL HAVE TO MONITOR THIS AND
ADJUST WITH TEMPO GROUPS FOR POSSIBLE CIG/VIS CONDITIONS IN TSRA AS
SHOWERS/STORMS MOVE WESTWARD. VFR CONDITIONS ARE EXPECTED OVERNIGHT.
&&
.MARINE...
EASTERLY WINDS WILL CONTINUE FOR THE NEXT SEVERAL DAYS. HIGH
PRESSURE BUILDING DOWN THE EASTERN SEABOARD FROM THE MID-ATLANTIC
STATES WILL ALSO SET UP A GOOD SYNOPTIC PATTERN TO SUPPORT A
NOCTURNAL EASTERLY WIND SURGE OVER THE COASTAL WATERS. THIS SURGE IS
FORECAST TO REACH CAUTIONARY LEVELS...SHOULD BEGIN SHORTLY AFTER
SUNSET...AND BE MOST NOTABLE THE FURTHER NORTH FROM ENGLEWOOD ONE
TRAVELS. ANOTHER EASTERLY SURGE TO CAUTIONARY LEVELS CAN BE EXPECTED
WEDNESDAY NIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 90 75 90 75 / 50 20 50 20
FMY 89 73 90 74 / 60 20 60 20
GIF 91 72 91 72 / 50 20 50 20
SRQ 91 74 90 74 / 50 20 60 20
BKV 91 70 91 70 / 40 20 50 20
SPG 90 77 89 77 / 50 20 60 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/MARINE...MROCZKA
AVIATION...RUDE/WYNN
AREA FORECAST DISCUSSION
NWS POCATELLO ID
750 AM MDT TUE SEP 17 2013
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT. A QUICK UPDATE THIS
MORNING TO ADD SEVERE WORDING TO GOING FORECAST THIS AFTERNOON AS
INCOMING FRONT AND UPPER DYNAMICS COMBINE TO PRODUCE VERY STRONG
THUNDERSTORMS. SEE PREVIOUS DISCUSSION BELOW. HUSTON
A VERY ACTIVE 48 HOUR PERIOD IS AHEAD FOR EASTERN IDAHO. WE ALREADY
HAD A ROUND OF STRONG/SEVERE STORMS THIS MORNING AND ANOTHER ROUND
IS ON TAP FOR LATER TODAY. THE MAIN FEATURE WITH STORM OFFSHORE WILL
SWING INTO WASHINGTON AND OREGON. THIS...ALONG WITH A COLD FRONT
ENTERING INTO WESTERN PORTIONS OF THE FORECAST AREA WILL KEEP
SHOWERS AND THUNDERSTORMS AROUND WITH COVERAGE RAMPING UP THIS
AFTERNOON. MOST AREAS WILL SEE SCATTERED TO NUMEROUS SHOWERS AND
STORMS...WITH EXCEPTION FOR THE MAGIC VALLEY AND WEST OF OAKLEY
WHERE ISOLATED ACTIVITY IS FORECAST. THE FRONT SHOULD BE THROUGH
THEM BEFORE THINGS GET GOING. THE THREAT OF STRONG/SEVERE STORMS
WITH HAIL AND STRONG WINDS EXISTS TODAY ESPECIALLY ACROSS THE
MOUNTAINS AND ALONG/AHEAD OF THE COLD FRONT ACROSS THE SNAKE PLAIN.
BY TONIGHT AND WEDNESDAY...THE FOCUS FOR SHOWERS WILL SHIFT TO THE
CENTRAL MOUNTAINS AND UPPER SNAKE HIGHLANDS. I KNOW SOME AREN`T
GOING TO BE READY OR LIKE THIS..BUT LIGHT SNOW IS FORECAST ABOVE
7500FT TONIGHT/EARLY WEDNESDAY ACROSS THE CENTRAL MOUNTAINS.
YOU CAN EXPECT BREEZY/WINDY CONDITIONS ACROSS THE AREA...WITH
SOUTHERLY WINDS AHEAD OF THE FRONT AND MORE WESTERLY IN ITS WAKE.
SUSTAINED WINDS OF 15-30MPH WITH HIGHER GUSTS ARE LIKELY...OUTSIDE
OF THUNDERSTORMS...THROUGH THIS EVENING. THE RIDGETOPS MAY SEE
SUSTAINED WINDS CLOSER TO 30-35MPH AT THEIR PEAK. WIND SPEEDS COME
DOWN SOME ESPECIALLY ACROSS THE CENTRAL MOUNTAINS AND UPPER SNAKE
HIGHLANDS TONIGHT AND TOMORROW. THEY`LL STILL BE BREEZY ACROSS
MOST OF THE SNAKE PLAIN AND SOUTHERN MOUNTAINS HOWEVER. WE HAVE A
LAKE WIND ADVISORY OUT FOR THIS AFTERNOON UNTIL JUST BEFORE
SUNSET. ANOTHER ONE IS LIKELY FOR TOMORROW AS WELL. CONDITIONS ARE
JUST NOT QUITE THERE FOR A WIND ADVISORY AT LOWER ELEVATIONS BUT
WE WILL BE MONITORING THIS AS WINDS WILL BE FLIRTING WITH THE
LOWER THRESHOLD OF 30MPH SUSTAINED TOMORROW. IT WILL CERTAINLY
FEEL LIKE FALL WITH COLDER TEMPERATURES ARRIVING BEHIND THE FRONT.
WE ARE LOOKING AT A 10-15 DEGREE DIFFERENCE BETWEEN TODAY AND
TOMORROW...WITH THE VALLEYS STRUGGLING TO GET ABOVE 65. WEDNESDAY
NIGHT WILL BE DOWNRIGHT COLD IN SOME AREAS. IT LOOKS LIKE MANY
AREAS WILL SEE 20S AND 30S FOR LOWS. THE EXCEPTIONS WILL BE ACROSS
THE SOUTHERN HIGHLANDS WHERE VALLEY TEMPERATURES WILL BOTTOM OUT
IN THE LOW 40S..AND PLACES LIKE STANLEY AND COPPER BASIN WHERE IT
WILL DROP INTO THE TEENS. KEYES
.LONG TERM...THURSDAY THROUGH NEXT TUESDAY. THE END OF THE WEEK
WILL SEE HIGH PRESSURE BUILDING AND SHIFTING EASTWARD OVER IDAHO.
THIS WILL ALLOW FOR A QUICK WARMUP WITH DRY CONDITIONS THROUGH
SATURDAY MORNING. FOR THE TRUE ARRIVAL OF FALL EARLY NEXT
WEEK...THE OVERALL PATTERN SETTLES BACK INTO GENERAL LOW PRESSURE
OVER THE WEST. THERE WILL BE MULTIPLE SYSTEMS IN THE PATTERN THAT
WILL KEEP THE CHANCE OF SHOWERS AROUND WITH A FEW THUNDERSTORMS.
KEYES
&&
.AVIATION...TRONG SHOWERS AND THUNDERSTORMS HAVE PASSED TO THE
DOWNWIND SIDE OF ALL AIRDROMES EXCEPT KIDA. -TSRA WILL CONTINUE AND
INCREASE IN COVERAGE AS INSTABILITY DEVELOPS AHEAD OF A COLD FRONT
EXPECTED LATE THIS AFTERNOON/EARLY THIS COMING EVENING...PASSING
THROUGH ALL AIRDROMES BY 18/03Z. -TSRA PROBABILITY BORDERS ON 50
PERCENT FOR KIDA AND KPIH...BUT TEMPO GROUPS NOT ALLOWED BEYOND 6
HOUR POINT. WILL TRY TO USE LATEST HRRR GUIDANCE TO FORECAST A
THUNDERSTORM TIME. FRONTAL PASSAGE IS FROM WEST TO EAST...WITH KIDA
BEING THE LAST. STRONG GRADIENT BEHIND THE FRONT MEANS AN UNUSUALLY
WINDY OVERNIGHT PERIOD TONIGHT. STRONG WIND CONTINUES WED AFTERNOON.
MESSICK
&&
.FIRE WEATHER...ERY UNSTABLE CONDITIONS TODAY WITH A FRONT ARRIVING
IN THE LATE AFTERNOON OVER EASTERN IDAHO. EXPECT A STORMY AND WINDY
DAY...CONTINUING INTO A STORMY AND WINDY NIGHT. FRONT WILL PASS OUT
OF EASTERN IDAHO BY MIDNIGHT TONIGHT...BUT STRONG WINDS WILL
CONTINUE OVERNIGHT AND INCREASE AGAIN TOMORROW AFTERNOON.
THUNDERSTORM ACTIVITY WILL BE LIMITED ON WED TO MAINLY THE TARGHEE
PORTION OF THE CARIBOU-TARGHEE NF. HIGH PRESSURE WILL MOVE IN FOR
THE LAST HALF OF THE WORK WEEK AND FOR AT LEAST A PORTION OF THE
WEEKEND. A STRONG LOW AND COLD FRONT ARE EXPECTED TO REACH IDAHO SAT
NIGHT OR SUN MORNING. NEITHER THE FRONT TODAY NOR THE WEEKEND FRONT
SHOULD BRING MUCH RAINFALL. MAIN ISSUE WILL BE STRONG WIND WITH A
90 KNOT UPPER LEVEL JET OVERHEAD TODAY MIXING DOWNWARD IN THE
UNSTABLE AIR. MESSICK
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM MDT THIS EVENING
IDZ021.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
750 AM EDT TUE SEP 17 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 508 AM EDT TUE SEP 17 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM
IL/WI INTO NW ONTARIO. AT THE SFC...A RIDGE WAS LOCATED OVER THE ERN
GREAT LAKES RESULTING IN SRLY THROUGH THE UPPER MS VALLEY INTO THE
WRN CWA. THE COMBINATION OF WAA AND A WEAK UPSTREAM SHORTWAVE TROUGH
OVER IA SUPPORTED AN AREA OF LIGHT SHOWERS FROM ERN NEB INTO NW IA.
OTHERWISE...IR LOOP INDICATED CLEAR SKIES OVER THE NRN GREAT LAKES.
TODAY...HIGH PRES AND THE LINGERING DRY AIRMASS WILL CONTINUE TO
DOMINATE THE WEATHER WITH MOSTLY SUNNY SKIES OVER UPPER MI. MIXING
TO AROUND 900-875 MB (AROUND 11C) WILL RESULT IN MAX READINGS IN THE
MID TO UPPER 60S.
TONIGHT...MDLS SUGGEST THAT AS THE IA SHRTWV GRADUALLY LIFTS TO THE
NORTHEAST...MOISTURE WILL INCREASE AND SOME LIGHT WAA PCPN WITH AREA
OF 300K-310K ISENTROPIC LIFT WILL SPREAD FROM SE MN AND WRN WI
TOWARD UPPER MI. THE NAM/GFS WERE A BIT MORE AGGRESSIVE IN BRINGING
SOME LIGHT PCPN INTO THE CWA COMPARED TO THE GEM/ECMWF. GIVEN THE
VERY DRY ANTECEDENT AIRMASS...THE FCST LEANS MORE TOWARD THE SLOWER
ONSET OF PCPN WITH ONLY A SLIGHT CHANCE OF LIGHT SHOWERS TOWARD 12Z
NEAR THE WI BORDER.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 447 AM EDT TUE SEP 17 2013
WED THROUGH MOST OF THU...A LOW PRESSURE SYSTEM CURRENTLY OFF THE
PACIFIC NW CONUS WILL DEEPEN WHILE MOVING FROM MT AT 12Z WED TO THE
CENTRAL SASKATCHEWAN/ONTARIO BORDER BY 00Z FRI. WILL DISCUSS PRECIP
ALONG THE COLD FRONT THAT MOVES IN LATE THU MOMENTARILY...BUT BEFORE
THAT MOVES IN EXPECT JUST SOME MINOR PRECIP. BEST CHANCE FOR PRECIP
LOOKS TO BE WITH BROAD WAA AHEAD OF THE SYSTEM...SO SOME LIGHT
PRECIP IS DIFFICULT TO FORECAST. HOWEVER...AGREE WITH PREVIOUS SHIFT
THAT SLIGHT CHANCE TO LOW CHANCE POPS SEEM WARRANTED PRIOR TO COLD
FROPA. HIGHS WED LOOK TO BE AROUND 70 WITH 850MB TEMPS OF 10-14C.
THU TEMPS LOOKS MORE CONDITIONAL AS LOW CLOUDS MAY INHIBIT MIXING OF
14-19C 850MB TEMPS...BUT COULD SEE HIGHS IN THE MID 70S IF ENOUGH
CLEARING OCCURS.
NOW FOR THE PROMISED DISCUSSION OF PRECIP ALONG THE COLD FRONT. THE
LOW WILL CONTINUE DEEPENING AS IT MOVES TO HUDSON BAY BY 00Z
SAT...THEN REMAINS NEARLY STATIONARY WHILE OCCLUDING THROUGH THE
REST OF SAT. WHILE DISCUSSING THE TRACK/TIMING OF THE SYSTEM...LET
IT BE SAID THAT MODELS ARE DOING MUCH BETTER THAN 24 HOURS
AGO...BOTH WITH RUN TO RUN CONTINUITY AND WITH MODEL TO MODEL
AGREEMENT. STILL THINK THERE WILL BE SHIFTS IN THE TRACK/TIMING BY
THE MODELS OVER THE NEXT FEW RUNS...BUT SHOULD AT LEAST BE GETTING A
BETTER IDEA OF WHAT THE SYSTEM WILL DO. THE COLD FRONT TIMING IS
ALSO SIMILAR BETWEEN MODEL RUNS...AT LEAST RELATIVELY SO FOR THIS
TYPE OF SYSTEM...WITH THE FRONT MOVING INTO THE FAR WRN CWA AROUND
00Z FRI...THEN TO THE CENTRAL CWA AROUND 12Z FRI AND TO THE ERN CWA
BY 18Z FRI. EXPECT A LINE OF SHOWERS AND THUNDERSTORMS TO MOVE
ACROSS THE CWA MAINLY THU NIGHT...AND AGREE WITH PREVIOUS SHIFT THAT
LIKELY POPS ARE JUSTIFIED. DRY SLOT MOVES IN BEHIND THE
FRONT...WHICH SHOULD BRING AN END TO SYNOPTIC PRECIP AS THE
MID/UPPER LEVELS DRY OUT. HOWEVER...WRAP AROUND MOISTURE WILL STILL
BE PRESENT IN THE LOW LEVELS AS THE UPPER TROUGH MOVES OVERHEAD FRI
INTO FRI NIGHT WITH 850MB TEMPS AS LOW AS 1C THROUGH 00Z FRI AND AS
LOW AS -2C FRI NIGHT. WLY LOW LEVEL WINDS MEANS THE W WIND LAKE
EFFECT/UPSLOPE BELTS WILL SEE THE BEST CHANCES FOR RAIN BEHIND THE
FRONT FRI AND FRI NIGHT.
MODELS DO START TO VARY MORE WITH HOW LONG TO LINGER THE UPPER
TROUGH OVER THE AREA SAT AND HOW QUICK TO BRING IN AN UPPER RIDGE
FROM THE W. THE GFS IS SLOWER WITH THE TROUGH AND HAS 850MB TEMPS
AROUND -2C AT 00Z SUN WHILE THE ECMWF HAS 850MB TEMPS OF 2-8C AT THE
SAME TIME. THEREFORE...HAVE LITTLE CONFIDENCE IN TEMPS FOR SAT. WITH
SUCH A SPREAD IN LOW LEVEL TEMPS...THERE IS ALSO A SPREAD IN
POSSIBILITIES FOR LAKE EFFECT RAIN...SO WILL CONTINUE TO HAVE SLIGHT
CHANCE IN THE FORECAST.
SUN SHOULD SEE A WARM UP AS THE UPPER RIDGE MOVES OVERHEAD...BUT
STILL NOT VERY CONFIDENT ON EXACT TEMPS FOR THE DAY GIVEN CONTINUED
MODEL SPREAD...BUT AT LEAST SHOULD BE WARMER AND DRIER THAN SAT.
MON SHOULD AGAIN SEE WARMING TEMPS AS SLY FLOW INCREASES AHEAD OF
THE NEXT LOW PRESSURE SYSTEM DEVELOPING OVER THE PLAINS. .
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 750 AM EDT TUE SEP 17 2013
WITH DRY HIGH PRES DOMINATING...VFR CONDITIONS WILL BE THE RULE FOR
MOST OF THE FCST PERIOD AT ALL 3 TAF SITES. AS THE HIGH DRIFTS
FARTHER E AND A STRONGER PRES GRADIENT TAKES SHAPE OVER THE NRN
GREAT LAKES...EXPECT A GUSTY S WIND TO DEVELOP BY THIS AFTERNOON
IN THE PRESENCE OF DAYTIME HEATING/MIXING. LLWS WILL RESULT TONIGHT WITH
NOCTURNAL COOLING CAUSING A RADIATION INVERSION AND DECOUPLING OF A
LIGHTER SFC FLOW FM THE STRONGER WINDS ABOVE THE INVERSION. LATE
TONIGHT...INCREASING LOW LEVEL MOISTURE MOVING NORTHWARD FROM WI IS
EXPECTED TO BRING MVFR CIGS INTO IWD/SAW TOWARD THE END OF THE FCST
PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EDT TUE SEP 17 2013
AS THE HIGH SHIFTS TO THE EAST...SRLY WINDS UP TO 20 KNOTS ARE
EXPECTED FROM TODAY INTO WED. WINDS SHOULD THEN REMAIN BELOW 20
KNOTS UNTIL FRI WHEN A COLD FRONT MOVES THROUGH THE REGION AND
BRINGS W TO NW WINDS UP TO 30 KNOTS FRI INTO SAT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FROST ADVISORY UNTIL 9 AM EDT /8 AM CDT/ THIS MORNING FOR MIZ002-
004>007-009>014-084-085.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
704 AM CDT Tue Sep 17 2013
.SHORT TERM: (Through Late This Afternoon)
Issued at 303 AM CDT Tue Sep 17 2013
Synoptic pattern over the region today will be dominated by broad
WAA overrunning the cooler Canadian airmass that backed into the
area Monday and overnight, which should certainly generate showers
and a few thunderstorms today in the northwest half of the CWA.
However, other than lead shortwave responsible for the light echoes
in se MO attm (which is outrunning better moisture) and some 850mb
theta-e advection vaguely focused over our n counties this morning,
mechanisms for precip are rather ill-defined. The lack of a
well-defined precip structure in the early morning regional radar
imagery is indicating the rather diffuse nature of the lift.
Plan to maintain broad PoP trends in current forecast with likely
POPS in our northwest counties to chance PoPs in se MO, although
specific numbers in a few locations will be changing to reflect
latest radar trends. In our e counties couldn`t rule out a few
sprinkles early today, but chances of measurable precip here look
low attm. Will make a last minute call on this.
Other concern for today is how warm to go on high temperatures, as
residual cool air and scattered showers will at least partially
offset warming due to the WAA. Still working on specifics but most
areas should remain in the 70s, with the coolest temps over the
northwest counties where clouds will be thickest and threat of
showers should be highest.
Truett
.LONG TERM: (Tonight through Monday)
Issued at 303 AM CDT Tue Sep 17 2013
Isolated to scattered SHRA/TSRA may continue percolating tonight due
to isentropic ascent along the 300-305 K surface, with the highest
precip chances across northeast MO and west central IL. Once the
second of two shortwaves (which were located over KS and OK early
this morning) and a warm front finally lift northeastward tonight,
precipitation should also lift away from the area.
Early morning water vapor imagery along and recent RUC 1.5 PVU
analyses depicted a strong vort max located just off the northern
CA coast. This feature is forecast to cross the Rockies and induce
surface cyclogenesis over SD/ND tomorrow, although it will also
influence conditions over MO/IL by producing weakly diffluent
southwesterly flow aloft. Between general moistening of the air
mass (PW values rise to around 1.7 inches by Wed night),
increasing H7-H5 lapse rates, and nocturnal LLJ activity, it`s
hard to rule out disorganized iso-sct precip for Wed and Wed
night, particularly across the northern and northeastern CWA. In
terms of the aforementioned low pressure system which will be
moving along the US/Canadian border and into southern Canada by
Thu night, models remain in general agreement with the overall
pattern despite some differences after 20/00z regarding a piece of
energy that breaks off near the base of the trough and then moves
across MO on Fri night. The cold front is forecast to approach the
CWA on Thu night and then move through on Fri/Fri night. Low level
convergence with the front, large scale ascent ahead of the upper
level trough axis, and favorable positioning beneath the right
entrance region of a jet at H25 all support likely PoPs for Thu
night and Fri across parts of the CWA. Precipitation is expected
to end from northwest to southeast due to post-frontal subsidence.
17/00z runs of the ECMWF/GFS/GEM all agree that a surface high
pressure center will build into the Great Lakes this weekend and
that there will be some degree of upper ridging over the Plains
ahead of the next progressive trough near the West Coast, but each
model has a different take on the upper level pattern east of the
Mississippi River with potential impacts for the MO/IL forecast.
The GFS depicts a closed low over the OH valley, the GEM brings a
tropical low northward from the Gulf of Mexico, and the ECMWF has
a weak upper trough axis oriented from LA through GA and into VA.
Since there is little confidence in any particular solution at
this time, the forecast grids for Sat-Mon generally reflect the
recommended CR initialization.
Kanofsky
&&
.AVIATION: (For the 12z TAFs through 12z Wednesday Morning)
Issued at 640 AM CDT Tue Sep 17 2013
As mentioned in the short term discussion, projected precip
pattern across the CWA is a bit chaotic today. However, feel the
greatest coverage of showers and scattered thunderstorms this
morning will be in the zone of strongest WAA/isentropic lift over
northwest parts of the CWA, and affecting the COU and UIN tafs.
Have attempted to time onset of TEMPO shower groups to leading
edge of echoes currently stretching from west central into
southwest MO. Meanwhile, only a few hit and miss showers are
expected for STL metro area tafs during the morning. Have omitted
TS for now as radar/satellite imagery and latest guidance don`t
offer any strong indications of an imminent threat at any of our
forecast points. As far as ceilings are concerned...looks like
MVFR and IFR that blankets the western half of Missouri will have
a tough time migrating too far east due to strong easterly
component to low level flow. Have held onto MVFR cigs 2-3kft at
COU throughout the morning, with ceilings lifting aoa 3kft no
later than midday. Ceilings elsewhere should be AOA 4kft
today...rising to a mid cloud deck tonight.
Specifics for KSTL: Ceilings around 4kft are expected today with
a few hit and miss showers during the morning that should
generally be on the light side. By tonight, forecast soundings
indicate mid and high level cloudiness.
Truett
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS RALEIGH NC
620 AM EDT TUE SEP 17 2013
.SYNOPSIS...
HIGH PRESSURE BUILDS OVER THE REGION TODAY BEHIND A COLD FRONT. THE
HIGH WILL REMAIN OVER THE REGION INTO THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 620 AM TUESDAY...
WITH THE SURFACE FRONT NOW WELL SOUTH OF CENTRAL NORTH CAROLINA...
DRIER MID-LEVEL AIR HAD MOVED INTO THE AREA FROM THE NORTH ON WATER
VAPOR IMAGERY. PRECIPITABLE WATER VALUES FALL TO A HALF-INCH OR LESS
BY TONIGHT...AS K INDICES FALL INTO MOSTLY NEGATIVE VALUES. FOR
TODAY...THE SURFACE GRADIENT TIGHTENS AS HIGH PRESSURE BUILDS
SOUTH...WITH BOTH THE NAM AND THE GFS BUFR SOUNDINGS SUGGESTING...
WITH MIXING...SURFACE WIND GUSTS FROM THE UPPER TEENS TO LOWER 20S
KTS COURTESY OF THE GRADIENT AND A 925MB WIND OF 20 TO 25KT EARLY
THIS MORNING. GUSTINESS SHOULD WANE DURING THE AFTERNOON AS THE
925MB WINDS DIMINISH TO 10 TO 15KT BY 00Z WEDNESDAY. THE 00Z TUESDAY
UPPER-AIR ANALYSIS SHOWED DECENT 850MB MOISTURE ACROSS MUCH OF THE
EASTERN SEABOARD...AND THE 00Z NAM BUFR SOUNDINGS SUGGESTED DECENT
850MB MOISTURE IN PLACE PROVIDING FOR THE LIKELIHOOD OF AT LEAST
SCATTERED CU/SC DURING THE DAY. ON THE OTHER HAND...THE GFS IS MUCH
DRIER AND CAPPED AT 850MB...AND THE LATEST NAM AND RAP BOTH ARE A
LITTLE LESS ROBUST WITH THE LOW-LEVEL MOISTURE...INCREASING THE
POTENTIAL FOR SOME HIGH-BASED CU OR SC LATER IN THE DAY AFTER
MORNING CLOUDS ERODE. THE CANADIAN CLOUD COVER MODEL IS SIMILAR...
AND LEANING THIS PARTLY TO MOSTLY CLOUDY CONDITIONS DURING THE VERY
EARLY MORNING SHOULD IMPROVE TO CONSIDERABLE SUNSHINE...WITH AREAS
OF PARTLY SUNNY CONDITIONS DEVELOPING THIS AFTERNOON AS SOME 850MB
MOISTURE MOVES IN FROM THE EAST AND NORTHEAST. 1000-850MB
THICKNESSES SUGGEST HIGHS...OVERALL...NEAR THE COOLER GFS MOS
GUIDANCE...FOR MAXES MOSTLY IN THE MID TO UPPER 70S.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 230 AM TUESDAY...
HIGH PRESSURE REMAINS IN PLACE THROUGH...AND BEYOND...THIS
SHORT-TERM PERIOD. THERE REMAINS A MODEST SURFACE GRADIENT TONIGHT...
SO DESPITE THE STRENGTH OF THE HIGH THERE SHOULD BE ENOUGH MIXING
UNDER THE INVERSION THAT WINDS SHOULD NOT GO COMPLETELY CALM...OR
COMPLETELY CALM FOR LONG. THE CLOUD FORECAST IS A LITTLE
CHALLENGING...AS THE GFS IN PARTICULAR ADVECTS SOME STRATOCU IN THE
LOW-LEVEL EASTERLY FLOW TOWARD THE COASTAL PLAIN LATE...WITH BOTH
THE NAM AND THE GFS...ALONG WITH THE CANADIAN CLOUD COVER MODEL...
SUGGESTIVE OF SOME MOSTLY THIN CIRRUS LATE FROM THE WEST AND
NORTHWEST. STAYED CLOSE TO GUIDANCE LOWS...LEANING MORE TOWARD THE
GFS AND ITS BIAS-CORRECTED MINS...FOR LOWS FROM THE UPPER 40S TOWARD
KTDF...KHNZ...AND KLHZ TO THE MID 50S OVER MUCH OF THE SANDHILLS AND
THE SOUTHERN COASTAL PLAIN. RECORD LOWS ARE ABOUT 5 DEGREES BELOW
FORECAST LOWS AT KGSO...KRDU...AND KFAY.
WEDNESDAY...AHEAD OF AN INCREASE IN POTENTIAL VORTICITY ON THE
1.5PVU SURFACE THAT BOTH THE NAM AND GFS FORECAST WEDNESDAY NIGHT...
AREAS OF HIGH CLOUDS ARE FORECAST WHICH ALSO SHOW UP ON THE CANADIAN
CLOUD COVER MODEL. WITH THAT LEVEL OF CONSISTENCY AMONG THE
GUIDANCE...WILL HAVE SKIES BECOMING PARTLY SUNNY IN THE GRIDDED
FORECAST DURING THE AFTERNOON FOR MOST LOCATIONS TURNING MOSTLY
CLEAR DURING THE EVENING. AGAIN...SUBTLE DISCREPANCIES OCCUR BETWEEN
THE NAM AND GFS THAT RESULT IN A CHALLENGING CLOUD COVER FORECAST
FOR OVERNIGHT WEDNESDAY NIGHT. THE NAM IS MUCH MORE AGGRESSIVE IN
INCREASING MID-LEVEL MOISTURE OVERNIGHT AT OR JUST ABOVE 500MB WITH
THE PASSAGE OF THE MODEST WAVE ON THE 1.5PVU SURFACE...WHILE THE GFS
IGNORES THIS AND WOULD IMPLY LIMITED CLOUD COVER. THIS HAS AN IMPACT
ON THE LOW TEMPERATURE FORECAST. UNDER A LIGHT WIND WITH THE SURFACE
RIDGE AXIS OVERHEAD...LOWS HAVE THE POTENTIAL TO BE COLDER THAN WHAT
SHOULD OCCUR TONIGHT. ON THE OTHER HAND...BOTH THE NAM AND THE GFS
MOS GUIDANCE ARE WARMER AT MOST EVERY LOCATION FOR WEDNESDAY NIGHT
COMPARED TO TONIGHT. THE GFS IS JUST ABOUT AS STRONG AS THE NAM WITH
ITS WAVE ON THE 1.5PVU SURFACE OVERNIGHT WEDNESDAY...SO WILL
ANTICIPATE AT LEAST A FEW CLOUDS MOVING THROUGH. WILL STILL FORECAST
A FEW 40S WEDNESDAY NIGHT BUT CONFINE THEM TO BASICALLY ALONG THE
VIRGINIA BORDER COUNTIES...SHOWING A DEGREE OR TWO INCREASE IN LOWS
IN MOST OTHER LOCATIONS FOR MOSTLY LOWER TO MID 50S. 1000-850MB
THICKNESSES ARE ABOUT 8M HIGHER WEDNESDAY COMPARED TO TODAY...BUT
WITH A FEW HIGH CLOUDS EXPECTED DURING THE AFTERNOON...THE MAX
TEMPERATURE FORECAST FOR WEDNESDAY IS BASICALLY PERSISTENCE FROM
TODAY.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 305 AM TUESDAY...
THU THROUGH FRI NIGHT: DEEP LAYER RIDGINGWILL CONTROL THE WEATHER
PATTERN OVER CENTRAL NC THIS PERIOD. RETURN FLOW WILL DEVELOP AROUND
THE CONTINENTAL POLAR SURFACE HIGH FORECAST TO BE CENTERED OVER THE
MIDDLE ATLANTIC STATES AT THE START OF THE PERIOD. THE COMBO OF THIS
RETURN FLOW AND SIGNIFICANT CP AIR MASS MODIFICATION BY A LATE
SUMMER SUN ANGLE WILL YIELD NEAR AVERAGE TEMPS FOR MID SEPTEMBER ON
THU. FURTHER WARMING WILL TAKE PLACE FRI IN STRENGTHENING RETURN
FLOW AND SUBSIDENCE BENEATH A 317 DM H7 RIDGE AXIS OVER THE SOUTHERN
APPALACHIANS. HIGHS IN THE MIDDLE TO UPPER 80S...OR A FEW DEGREES
WARMER THAN WHAT FORECAST LOW LEVEL THICKNESSES - WHICH HAVE YIELDED
A COOL BIAS IN RECENT WEEKS - WOULD SUGGEST. LOWS...WITH GOOD
RADIATIONAL COOLING ASSOCIATED WITH MOSTLY CLEAR AND CALM IN THE
RIDGE AXIS...ARE FORECAST ON THE COOL SIDE OF GUIDANCE - IN LINE
WITH CLIMO FOR PROJECTED LL THICKNESSES IN THE 1380 TO AROUND 1390
METER RANGE.
SAT THROUGH MON: THE FIRST IN A SERIES OF A FEW STRONG AND
PROGRESSIVE UPPER LOWS/TROUGHS FORECAST TO MIGRATE EASTWARD ACROSS
THE NORTHERN TIER OF THE CONUS/SOUTHERN CANADA WILL PROPEL AN
ACCOMPANYING SURFACE COLD FRONT FROM THE TN VALLEY EARLY SAT...TO
THE SPINE OF THE APPALACHIAN CHAIN BY SUN MORNING...WITH PRECEDING
PRE-FRONTAL TROUGHING IN THE LEE OF THE APPALACHIANS. MEDIUM RANGE
GUIDANCE...ASIDE FROM THE DISCOUNTED 00Z/17TH GFS SOLUTION...HAS
COME INTO EXCELLENT AGREEMENT REGARDING THIS EVOLUTION AND
ASSOCIATED FRONTAL PASSAGE THROUGH CENTRAL NC ON SUN. THERE HAS BEEN
A TREND TOWARD A STRONGER SOUTHERN STREAM PORTION OF THE LONGWAVE
TROUGH ALOFT...WHICH WILL LIKELY SUPPORT SOME SORT OF SURFACE
CYCLOGENESIS FROM THE NW CARIBBEAN TO THE SW ATLANTIC LATE IN THE
WEEKEND INTO EARLY NEXT WEEK. GIVEN THE PROGRESSIVE NATURE OF THE
FLOW ALOFT...HOWEVER...ANY SUCH DEVELOPMENT WOULD BE TOO FAR SOUTH
AND EAST TO AFFECT OUR AREA...WHICH IS WHY THE 00Z/17TH GFS SOLUTION
WAS DISCOUNTED AS NOTED ABOVE.
SENSIBLE WEATHER HIGHLIGHTS WILL FEATURE SCATTERED SHOWERS AND
ISOLATED THUNDER IN AN ALBEIT ONLY WEAKLY UNSTABLE WARM SECTOR...
PARTICULARLY INVOF THE LEE TROUGH OVER THE PIEDMONT...SAT AFTERNOON
AND NIGHT. SCATTERED TO NUMEROUS SHOWERS AND STORMS AREA-WIDE...
AMIDST AGAIN ONLY WEAK INSTABILITY...ARE THEN FAVORED WITH THE SLOW
PASSAGE OF THE SURFACE COLD FRONT ON SUN. POST-FRONTAL SURFACE HIGH
PRESSURE WILL FOLLOW FOR MON...THOUGH WITH A LINGERING CHANCE OF A
SHOWER OR STORM OVER SE NC...INVOF THE SLOW-MOVING FRONT.
TEMPERATURES WILL TREND FROM THE MIDDLE...TO PERHAPS A FEW UPPER 80S
IN THE COASTAL PLAIN...SAT...TO AROUND SEASONAL AVERAGES AROUND 80
DEGREES ON MON.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 620 AM TUESDAY...
VFR CONDITIONS ARE EXPECTED THROUGH THE 12Z VALID TAF PERIOD. VERY
PATCHY MVFR CLOUDS CONTINUED MAINLY TOWARD KGSB AND A FEW OF THESE
COULD STILL BRIEFLY AFFECT KFAY BEFORE DRIER AIR MOVING IN FROM THE
NORTH RESULTS IN A HIGH PROBABILITY OF VFR CONDITIONS. AS HIGH
PRESSURE BUILDS SOUTH...THE GRADIENT AROUND THE HIGH SHOULD RESULT
IN GUSTY WINDS...WITH SEVERAL GUSTS EXPECTED FROM THE UPPER TEENS TO
LOWER 20S KNOTS BY MID-MORNING THROUGH MID-AFTERNOON BEFORE SOME OF
THE GUSTINESS WANES LATE. 925MB WINDS DIMINISH TO 10 TO 15KT BY 00Z
WEDNESDAY. UNDER VFR CONDITIONS TONIGHT...EAST-NORTHEAST WINDS OFF
OF THE SURFACE COULD INCREASE TO THE UPPER TEENS TO NEAR 25KT BY 03Z
AT THE INVERSION...STRONGEST TOWARD KFAY AND LIGHTEST MORE TOWARD
THE RIDGE AXIS TOWARD KGSO AND KINT.
BEYOND THE 12Z VALID TAF PERIOD...LOCAL MVFR CONDITIONS IN LIGHT FOG
ARE POSSIBLE WEDNESDAY NIGHT...AND DEPENDING ON ANY MID-LEVEL CLOUD
COVER...VERY LOCALLY IFR CONDITIONS COULD OCCUR TOWARD KRWI. SIMILAR
CONDITIONS ARE POSSIBLE DURING THE REST OF THE WORK WEEK. BY
SATURDAY...THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS AHEAD OF
LOW PRESSURE AND A SURFACE FRONT.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF
SHORT TERM...DJF
LONG TERM...MWS
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
933 AM CDT TUE SEP 17 2013
.UPDATE...
ISSUED AT 931 AM CDT TUE SEP 17 2013
MADE SOME SLIGHT CLOUD TREND ADJUSTMENTS BASED ON CURRENT
SATELLITE TRENDS OTHERWISE CURRENT FORECAST LOOKING GOOD SO FAR
AND NO OTHER CHANGES MADE.
UPDATE ISSUED AT 656 AM CDT TUE SEP 17 2013
LEADING EDGE OF LOW CLOUDS IS NOW ALONG A COOPERSTOWN TO WAHPETON
LINE AND CONTINUES TO MOVE NORTH-NORTHEAST AROUND 35 MPH. BACK EDGE
OF CLOUD DECK IS A BIT FARTHER WEST THAN PREVIOUS FORECAST...SO
ADJUSTED SKY GRIDS TO REFLECT LATEST OBSERVATIONS. AS A RESULT...
EXPECT ALL BUT THE FAR NORTHWEST FORECAST AREA TO BECOME MOSTLY
CLOUDY BY LATE MORNING INTO THE EARLY AFTERNOON. LATEST HRRR
SUGGESTS THE SUN MAY PEAK OUT FOR A COUPLE HOURS ALONG THE VALLEY
FLOOR BEFORE SUNSET. OTHERWISE...AREAS TO THE EAST WILL REMAIN
CLOUDY FOR MUCH OF THE NIGHT. ALSO DECREASED TEMPERATURES A FEW
DEGREES ACROSS THE NORTHERN VALLEY INTO NORTHWEST MN TO ACCOUNT
FOR MORE EXPANSIVE CLOUDS. REST OF THE FORECAST IN GOOD SHAPE WITH
NO MAJOR CHANGES AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 414 AM CDT TUE SEP 17 2013
CHALLENGES INCLUDE CLOUD COVER AND TEMPERATURES TODAY/TONIGHT AND
THEN PRECIPITATION CHANCES/SEVERE POTENTIAL WEDNESDAY NIGHT INTO
THURSDAY. GFS/NAM/ECMWF/GEM IN GOOD OVERALL AGREEMENT AND WILL
USE A BLENDED SOLUTION FOR THIS FORECAST PACKAGE.
FOR TODAY...MOIST SOUTHERLY FLOW BETWEEN THE SURFACE HIGH ACROSS
THE GREAT LAKES AND DEVELOPING LOW IN THE LEE OF THE NORTHERN ROCKIES
WILL ADVECT LOW CLOUDS CURRENTLY ACROSS EASTERN SD/SOUTHERN MN/
NE/IA NORTHWARD ACROSS THE FORECAST AREA. RAP 925 HPA RH SUGGESTS
THESE CLOUDS WILL MOVE INTO THE SOUTHERN FORECAST AREA BY 12 UTC
AND THEN ALONG AND EAST OF THE VALLEY BY THIS AFTERNOON. AREAS
WITH PERSISTENT CLOUD COVER NOT LIKELY TO RISE ABOVE 70 DEGREES.
LOWER TO MID 70S ARE POSSIBLE ACROSS THE DEVILS LAKE BASIN AND
NORTHERN VALLEY WHERE MORE SUNSHINE IS EXPECTED. TODAY WILL ALSO
BE BREEZY TO LOCALLY WINDY WITH 30 KTS IN THE MIXED LAYER. THIS
SHOULD TRANSLATE TO SURFACE WINDS FROM 15 TO 25 MPH WITH GUSTS UP
TO 30 MPH.
LOW CLOUDS WILL BE VERY SLOW TO DISSIPATE OVERNIGHT...ESPECIALLY
ACROSS THE EASTERN FORECAST AREA. MODEL SOUNDINGS SUGGEST THE
POSSIBILITY OF SOME LIGHT DRIZZLE...BUT GIVEN LOW SENSIBLE WEATHER
IMPACT AND COVERAGE UNCERTAINTY...WILL NOT INCLUDE IN CURRENT
GRIDS. SOUTHERLY WINDS WILL REMAIN ELEVATED BETWEEN 10 AND 15
MPH WITH LOW TEMPERATURES GENERALLY IN THE 50S.
STRONG POSITIVE THERMAL ADVECTION IN THE WARM SECTOR OF AN
APPROACHING PACIFIC WAVE WILL RESULT IN TEMPERATURES WELL ABOVE
NORMAL ON WEDNESDAY. AFTERNOON HIGHS WILL CLIMB INTO THE MID 70S
TO LOWER 80S. SOUTHERLY WIND WILL NOT BE AS STRONG AS TODAY. MOST
OF THE DAY SHOULD BE DRY WITH ONLY A CHANCE FOR AFTERNOON SHOWERS
AND THUNDERSTORMS ACROSS THE DEVILS LAKE BASIN.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 414 AM CDT TUE SEP 17 2013
A STRONG SURFACE LOW WILL TRACK ACROSS ND WEDNESDAY EVENING AND
INTO THE CENTRAL/NORTHERN VALLEY BY 06 UTC THURSDAY. WARM
TEMPERATURES ALOFT MAY LIMIT CONVECTIVE INITIATION...BUT THE
COMBINATION OF MLCAPE UP TO 2000 J/KG...PWATS AROUND 1.5 INCHES...
AN APPROACHING SURFACE COLD FRONT AND INCREASING BULK SHEAR FROM A
300 HPA JET STREAK SHOULD RESULT IN THUNDERSTORM DEVELOPMENT
ACROSS EASTERN ND INTO NORTHWEST MN. SOME STORMS NEAREST TO THE
SURFACE LOW MAY BECOME SEVERE AND THIS IS HIGHLIGHTED IN THE SPC
DAY 2 CONVECTIVE OUTLOOK WHICH SHOWS A SLIGHT RISK ALONG AND
NORTHWEST OF A LINE FROM CARRINGTON TO GRAND FORKS TO HALLOCK.
TOO EARLY TO ADD SEVERE WORDING TO THE GRIDS...BUT SOMETHING TO
WATCH.
WITH THE EXCEPTION OF SOME WRAP-AROUND SHOWERS LATE WEDNESDAY
NIGHT INTO THURSDAY ACROSS THE NORTHERN FORECAST AREA...MOST OF
EASTERN ND/NORTHWEST MN WILL BE DRY-SLOTTED ONCE CONVECTION MOVES
INTO CENTRAL AND EAST CENTRAL MN BY 12 UTC THURSDAY. STRONG
WESTERLY WINDS WILL FOLLOW IN THE WAKE OF THE SURFACE FRONT...
ALONG WITH A MUCH COOLER AIR MASS. HIGH TEMPERATURES THURSDAY WILL
RANGE FROM THE LOW 60S ACROSS THE DEVILS LAKE BASIN TO THE LOW 70S
ACROSS WEST CENTRAL MN LAKES COUNTRY. WEST WINDS WILL RANGE FROM
15 TO 25 MPH.
FRIDAY THROUGH MONDAY...THE WEEK WILL END QUIET AND COOL WITH
NORTHWESTERLY FLOW BEHIND THE DEPARTING TROUGH AND HIGH PRESSURE
BUILDING INTO THE PLAINS. A FEW SHOWERS MAY LINGER OVER LAKE OF THE
WOODS AREA BUT OTHERWISE THINK WE WILL BE DRY THROUGH FRIDAY AND
INTO SATURDAY. THE WEEKEND WILL SEE A SLOW WARMING TREND AS
SOUTHERLY WINDS RETURN. THE MAIN UPPER TROUGH WILL REMAIN OVER THE
WESTERN CONUS THROUGH THE END OF THE PERIOD BUT MODELS ALL SHOW
SIGNS OF A LEAD SHORTWAVE MOVING FROM THE NORTHERN ROCKIES THROUGH
THE PLAINS LATE SUNDAY AND INTO MONDAY. KEPT FAIRLY HIGH POPS GOING
FOR SUNDAY NIGHT AND MONDAY AS A WEAK SFC TROUGH AXIS/FRONTAL
BOUNDARY MOVES THROUGH. TEMPS WILL BE A FEW DEGREES LOWER ON MONDAY
BUT STILL AROUND SEASONAL AVERAGES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 656 AM CDT TUE SEP 17 2013
FRONT EDGE OF MVFR CLOUD DECK NOW EXTENDS FROM KS32 TO KBWP AND IS
MOVING NORTH-NORTHEAST AROUND 30 KTS. ADJUSTED TIMING OF CEILINGS
FOR 12 UTC TAFS BASED ON LATEST OBSERVATIONAL TRENDS. THINK KDVL WILL
BE RIGHT ON THE EDGE OF THE CLOUDS THROUGH THE DAY...SO WILL KEEP
IT SCATTERED FOR NOW. SOUTHERLY WINDS WILL BE ELEVATED THROUGH THE
PERIOD WITH AFTERNOON GUSTS AROUND 25 KTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...ROGERS
LONG TERM...ROGERS/JR
AVIATION...ROGERS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
656 AM CDT TUE SEP 17 2013
.UPDATE...
ISSUED AT 656 AM CDT TUE SEP 17 2013
LEADING EDGE OF LOW CLOUDS IS NOW ALONG A COOPERSTOWN TO WAHPETON
LINE AND CONTINUES TO MOVE NORTH-NORTHEAST AROUND 35 MPH. BACK EDGE
OF CLOUD DECK IS A BIT FARTHER WEST THAN PREVIOUS FORECAST...SO
ADJUSTED SKY GRIDS TO REFLECT LATEST OBSERVATIONS. AS A RESULT...
EXPECT ALL BUT THE FAR NORTHWEST FORECAST AREA TO BECOME MOSTLY
CLOUDY BY LATE MORNING INTO THE EARLY AFTERNOON. LATEST HRRR
SUGGESTS THE SUN MAY PEAK OUT FOR A COUPLE HOURS ALONG THE VALLEY
FLOOR BEFORE SUNSET. OTHERWISE...AREAS TO THE EAST WILL REMAIN
CLOUDY FOR MUCH OF THE NIGHT. ALSO DECREASED TEMPERATURES A FEW
DEGREES ACROSS THE NORTHERN VALLEY INTO NORTHWEST MN TO ACCOUNT
FOR MORE EXPANSIVE CLOUDS. REST OF THE FORECAST IN GOOD SHAPE WITH
NO MAJOR CHANGES AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 414 AM CDT TUE SEP 17 2013
CHALLENGES INCLUDE CLOUD COVER AND TEMPERATURES TODAY/TONIGHT AND
THEN PRECIPITATION CHANCES/SEVERE POTENTIAL WEDNESDAY NIGHT INTO
THURSDAY. GFS/NAM/ECMWF/GEM IN GOOD OVERALL AGREEMENT AND WILL
USE A BLENDED SOLUTION FOR THIS FORECAST PACKAGE.
FOR TODAY...MOIST SOUTHERLY FLOW BETWEEN THE SURFACE HIGH ACROSS
THE GREAT LAKES AND DEVELOPING LOW IN THE LEE OF THE NORTHERN ROCKIES
WILL ADVECT LOW CLOUDS CURRENTLY ACROSS EASTERN SD/SOUTHERN MN/
NE/IA NORTHWARD ACROSS THE FORECAST AREA. RAP 925 HPA RH SUGGESTS
THESE CLOUDS WILL MOVE INTO THE SOUTHERN FORECAST AREA BY 12 UTC
AND THEN ALONG AND EAST OF THE VALLEY BY THIS AFTERNOON. AREAS
WITH PERSISTENT CLOUD COVER NOT LIKELY TO RISE ABOVE 70 DEGREES.
LOWER TO MID 70S ARE POSSIBLE ACROSS THE DEVILS LAKE BASIN AND
NORTHERN VALLEY WHERE MORE SUNSHINE IS EXPECTED. TODAY WILL ALSO
BE BREEZY TO LOCALLY WINDY WITH 30 KTS IN THE MIXED LAYER. THIS
SHOULD TRANSLATE TO SURFACE WINDS FROM 15 TO 25 MPH WITH GUSTS UP
TO 30 MPH.
LOW CLOUDS WILL BE VERY SLOW TO DISSIPATE OVERNIGHT...ESPECIALLY
ACROSS THE EASTERN FORECAST AREA. MODEL SOUNDINGS SUGGEST THE
POSSIBILITY OF SOME LIGHT DRIZZLE...BUT GIVEN LOW SENSIBLE WEATHER
IMPACT AND COVERAGE UNCERTAINTY...WILL NOT INCLUDE IN CURRENT
GRIDS. SOUTHERLY WINDS WILL REMAIN ELEVATED BETWEEN 10 AND 15
MPH WITH LOW TEMPERATURES GENERALLY IN THE 50S.
STRONG POSITIVE THERMAL ADVECTION IN THE WARM SECTOR OF AN
APPROACHING PACIFIC WAVE WILL RESULT IN TEMPERATURES WELL ABOVE
NORMAL ON WEDNESDAY. AFTERNOON HIGHS WILL CLIMB INTO THE MID 70S
TO LOWER 80S. SOUTHERLY WIND WILL NOT BE AS STRONG AS TODAY. MOST
OF THE DAY SHOULD BE DRY WITH ONLY A CHANCE FOR AFTERNOON SHOWERS
AND THUNDERSTORMS ACROSS THE DEVILS LAKE BASIN.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 414 AM CDT TUE SEP 17 2013
A STRONG SURFACE LOW WILL TRACK ACROSS ND WEDNESDAY EVENING AND
INTO THE CENTRAL/NORTHERN VALLEY BY 06 UTC THURSDAY. WARM
TEMPERATURES ALOFT MAY LIMIT CONVECTIVE INITIATION...BUT THE
COMBINATION OF MLCAPE UP TO 2000 J/KG...PWATS AROUND 1.5 INCHES...
AN APPROACHING SURFACE COLD FRONT AND INCREASING BULK SHEAR FROM A
300 HPA JET STREAK SHOULD RESULT IN THUNDERSTORM DEVELOPMENT
ACROSS EASTERN ND INTO NORTHWEST MN. SOME STORMS NEAREST TO THE
SURFACE LOW MAY BECOME SEVERE AND THIS IS HIGHLIGHTED IN THE SPC
DAY 2 CONVECTIVE OUTLOOK WHICH SHOWS A SLIGHT RISK ALONG AND
NORTHWEST OF A LINE FROM CARRINGTON TO GRAND FORKS TO HALLOCK.
TOO EARLY TO ADD SEVERE WORDING TO THE GRIDS...BUT SOMETHING TO
WATCH.
WITH THE EXCEPTION OF SOME WRAP-AROUND SHOWERS LATE WEDNESDAY
NIGHT INTO THURSDAY ACROSS THE NORTHERN FORECAST AREA...MOST OF
EASTERN ND/NORTHWEST MN WILL BE DRY-SLOTTED ONCE CONVECTION MOVES
INTO CENTRAL AND EAST CENTRAL MN BY 12 UTC THURSDAY. STRONG
WESTERLY WINDS WILL FOLLOW IN THE WAKE OF THE SURFACE FRONT...
ALONG WITH A MUCH COOLER AIR MASS. HIGH TEMPERATURES THURSDAY WILL
RANGE FROM THE LOW 60S ACROSS THE DEVILS LAKE BASIN TO THE LOW 70S
ACROSS WEST CENTRAL MN LAKES COUNTRY. WEST WINDS WILL RANGE FROM
15 TO 25 MPH.
FRIDAY THROUGH MONDAY...THE WEEK WILL END QUIET AND COOL WITH
NORTHWESTERLY FLOW BEHIND THE DEPARTING TROUGH AND HIGH PRESSURE
BUILDING INTO THE PLAINS. A FEW SHOWERS MAY LINGER OVER LAKE OF THE
WOODS AREA BUT OTHERWISE THINK WE WILL BE DRY THROUGH FRIDAY AND
INTO SATURDAY. THE WEEKEND WILL SEE A SLOW WARMING TREND AS
SOUTHERLY WINDS RETURN. THE MAIN UPPER TROUGH WILL REMAIN OVER THE
WESTERN CONUS THROUGH THE END OF THE PERIOD BUT MODELS ALL SHOW
SIGNS OF A LEAD SHORTWAVE MOVING FROM THE NORTHERN ROCKIES THROUGH
THE PLAINS LATE SUNDAY AND INTO MONDAY. KEPT FAIRLY HIGH POPS GOING
FOR SUNDAY NIGHT AND MONDAY AS A WEAK SFC TROUGH AXIS/FRONTAL
BOUNDARY MOVES THROUGH. TEMPS WILL BE A FEW DEGREES LOWER ON MONDAY
BUT STILL AROUND SEASONAL AVERAGES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 656 AM CDT TUE SEP 17 2013
FRONT EDGE OF MVFR CLOUD DECK NOW EXTENDS FROM KS32 TO KBWP AND IS
MOVING NORTH-NORTHEAST AROUND 30 KTS. ADJUSTED TIMING OF CEILINGS
FOR 12 UTC TAFS BASED ON LATEST OBSERVATIONAL TRENDS. THINK KDVL WILL
BE RIGHT ON THE EDGE OF THE CLOUDS THROUGH THE DAY...SO WILL KEEP
IT SCATTERED FOR NOW. SOUTHERLY WINDS WILL BE ELEVATED THROUGH THE
PERIOD WITH AFTERNOON GUSTS AROUND 25 KTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...ROGERS
SHORT TERM...ROGERS
LONG TERM...ROGERS/JR
AVIATION...ROGERS
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
230 PM EDT TUE SEP 17 2013
.SYNOPSIS...
18Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN UPPER LEVEL PATTERN
THAT IS HIGHLY AMPLIFIED TO THE NORTH THROUGH THE MIDDLE SECTION OF
THE COUNTRY. THIS LARGE RIDGE SITS BETWEEN TWO SHARP TROUGHS ALONG
BOTH THE PACIFIC AND ATLANTIC SEABOARDS. THE FLORIDA PENINSULA
RESIDES UNDER A WEAK UPPER LEVEL PATTERN ON THE EASTERN PERIPHERY OF
ELONGATED UPPER RIDGING ALONG THE NORTHERN GULF COAST.
AT THE SURFACE...FORECAST AREA RESIDES WITHIN A FAIRLY TIGHT
PRESSURE GRADIENT ZONE BETWEEN STRONG 1025+MB HIGH PRESSURE RIDGING
DOWN THE ATLANTIC SEABOARD...AND A WEAK AREA OF LOW PRESSURE NEAR
THE YUCATAN PENINSULA OF MEXICO. THIS GRADIENT IS PROVIDING A
DEFINED EASTERLY TO NORTHEASTERLY LOW LEVEL FLOW ACROSS THE
PENINSULA. SCT TO NMRS GENERALLY SHALLOW SHOWERS AND A FEW STORMS
ARE NOW FORMING INLAND FROM THE FL EAST COAST AND RAPIDLY
PROPAGATING WESTWARD WITHIN THIS FLOW. THE GREATEST COVERAGE OF
STORMS THROUGH THE REMAINDER OF THE AFTERNOON LOOKS TO BE SOUTH OF
THE I-4 CORRIDOR...WITH MORE WIDELY SCT ACTIVITY FURTHER TO THE
NORTH ACROSS THE NATURE COAST. THIS SCENARIO IS IN GOOD AGREEMENT
WITH THE LATEST HI-RESOLUTION GUIDANCE ENSEMBLE.
&&
.SHORT TERM (TONIGHT THROUGH THURSDAY)...
TONIGHT...
SHOWERS AND STORMS PUSH OFFSHORE DURING THE EVENING HOURS...AND THE
PATTERN SUGGEST WE WILL LIKELY SEE AT LEAST SOME CONVECTIVE COVERAGE
OVER THE SOUTHERN COASTAL WATERS WELL INTO THE OVERNIGHT. HIGH
PRESSURE BUILDING DOWN THE EASTERN SEABOARD FROM THE MID-ATLANTIC
STATES WILL ALSO SET UP A GOOD SYNOPTIC PATTERN TO SUPPORT A
NOCTURNAL EASTERLY WIND SURGE OVER THE COASTAL WATERS. THIS SURGE
THAT IS FORECAST TO REACH CAUTIONARY LEVELS...SHOULD BEGIN SHORTLY
AFTER SUNSET...AND BE MOST NOTABLE THE FURTHER NORTH FROM ENGLEWOOD
ONE TRAVELS.
WEDNESDAY/WEDNESDAY NIGHT...
THE SYNOPTIC SETUP FOR WEDNESDAY APPEARS VERY SIMILAR TO WHAT WE ARE
EXPERIENCING TODAY (TUESDAY). UPPER LEVELS SHOW WEAK FLOW ON THE
EASTERN SIDE OF A BROAD...BUT NOT STRONG....UPPER RIDGE. AT THE
SURFACE...RIDGING CONTINUES TO BUILD DOWN THE EASTERN SEABOARD...AND
IF ANYTHING...THE GRADIENT IS TIGHTER AND THE RESULTING LOW LEVEL
FLOW A TAD STRONGER. ONCE AGAIN THE COLUMN WILL BE QUITE MOIST...AND
THIS COMBINED WITH THE FAVORABLE EASTERLY FLOW SHOULD SUPPORT
SCT-NMRS SHOWERS AND STORMS...WITH THE GREATEST COVERAGE ALONG AND
SOUTH OF I-4. CURRENT FORECAST RAIN CHANCES SHOW 60-65% ALONG AND
SOUTH OF I-4 AND 40-55% FURTHER NORTH. ASIDE FROM THE ACTUAL RAIN
CHANCES...THE MID-LEVELS DO NOT LOOK TO SUPPORT MANY STRONGER
UPDRAFTS. 500MB TEMPS ARE FAIRLY WARM AT -6C AND THIS SHOULD HELP
SUPPRESS MUCH IN THE WAY OF STRONG/SEVERE STORMS...AND EVEN
EFFICIENT CHARGE SEPARATION FOR MANY FREQUENT LIGHTNING PRODUCERS.
OF COURSE...ALL LIGHTNING IS DANGEROUS...REGARDLESS OF ITS
FREQUENCY. THE SPATIAL AND TEMPORAL EVOLUTION OF THE STORMS SHOULD
FOLLOW A SIMILAR PATTERN TO TUESDAY AS WELL. DAY WILL START WITH
SPEED CONVERGENCE SHOWERS ALONG THE FLORIDA EAST COAST. THESE WILL
STRUGGLE TO MOVE INLAND THROUGH LATE MORNING AND THEN CONVECTION
WILL BEGIN INLAND ALONG RESIDUAL OUTFLOW BOUNDARIES AND PROPAGATE
RAPIDLY WESTWARD ACROSS OUR ZONES. TEMPERATURES APPEAR SEASONABLE BY
MID-AFTERNOON REACHING THE LOW 90S FOR MOST SPOTS THAT DO NOT SEE AN
EARLY SHOWER.
ANY LEFTOVER EVENING STORMS PUSH OFFSHORE BY 02-03Z LEAVING A
GENERALLY DRY OVERNIGHT INTO EARLY THURSDAY MORNING. THE RIDGE
POSITION TO OUR NORTH WILL SUPPORT ANOTHER CAUTIONARY EASTERLY WIND
SURGE FOR THE COASTAL WATERS...ESPECIALLY FROM OFFSHORE OF TAMPA BAY
NORTHWARD ALONG THE NATURE COAST.
THURSDAY...
PATTERN STILL DOES NOT CHANGE A WHOLE LOT INTO THURSDAY. A SLIGHTLY
MORE AMPLIFIED MID/UPPER LEVEL RIDGE TO OUR WEST IS SHOWN BY THE GFS
TO BEGIN DELIVERING SOME DRIER MID-LEVEL AIR TO THE NATURE COAST
ZONES BEFORE THE DAY IS THROUGH. DEPENDING ON THE EXACT TIMING OF
THIS DRIER AIR...RAIN CHANCES FOR THE NATURE COAST MAY NEED TO BE
ADJUSTED DOWNWARD SLIGHTLY. EITHER WAY...BEST RAIN CHANCES THURSDAY
AFTERNOON/EARLY EVENING WILL ONCE AGAIN BE ALONG AND SOUTH OF I-4.
CURRENTLY FORECASTING 55-65% SOUTH OF I-4 AND 30-45% FURTHER NORTH.
&&
.LONG TERM (FRIDAY THROUGH NEXT MONDAY)...
MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT THROUGH THE REMAINDER OF
THE WORK WEEK...WITH SOLUTIONS THEN DIVERGING OVER THE UPCOMING
WEEKEND AND INTO EARLY NEXT WEEK. THE 00Z CANADIAN MODEL COMPARED
WITH THE GFS/ECMWF IS DEVELOPING A TROPICAL CYCLONE IN THE GULF OF
MEXICO BY SATURDAY EVENING. ALTHOUGH NOT IMPOSSIBLE GIVEN THE
GENERALLY FAVORABLE CONDITIONS OVER THE GULF...ONE OF THE BIASES OF
THE CANADIAN MODEL IS TO OVERDEVELOP TROPICAL CYCLONES DUE TO
INTERACTION WITH LARGE SCALE SYNOPTIC FEATURES. AS A RESULT...WILL
FOLLOW A BLEND OF THE 00Z GFS AND 00Z ECMWF FOR FORECAST DETAILS
THROUGH THE LONG TERM PERIODS.
HIGH PRESSURE WILL REMAIN NORTH OF THE FORECAST AREA FOR THE TAIL
END OF THE WORK WEEK AND INTO THE UPCOMING WEEKEND...RESULTING IN
PREVAILING EASTERLY FLOW WITH ISOLATED TO WIDELY SCATTERED SEA
BREEZE DRIVEN CONVECTION EACH AFTERNOON/EVENING THROUGH SATURDAY.
HIGH PRESSURE NORTH OF THE STATE WILL WEAKEN AS A FRONTAL BOUNDARY
PUSHES SOUTHWARD TOWARD THE NORTHERN GULF COAST AND STALLS OUT BY
SUNDAY. THIS WILL RESULT IN AN INCREASE IN DEEP LAYER MOISTURE
ACROSS THE ENTIRE FORECAST AREA...SUNDAY THROUGH NEXT TUESDAY. THE
GFS AND ECMWF MODELS TO DIFFERING DEGREES CONTINUE TO SHOW A BROAD
AREA OF LOW PRESSURE WITH PLENTY OF DEEP LAYER MOISTURE IN PLACE
OVER THE GULF OF MEXICO. THE CANADIAN ON THE OTHER HAND AS
MENTIONED ABOVE...HAS A FAIRLY IMPRESSIVE TROPICAL CYCLONE MAKING
LANDFALL ALONG THE NORTHERN GULF COAST ON SUNDAY. GIVEN THE TIME
OF YEAR AND SOME INDICATIONS OF POTENTIAL DEVELOPMENT IN THE
NUMERICAL MODEL GUIDANCE...WILL NEED TO CLOSELY MONITOR TRENDS AS
THE WEEK PROGRESSES FOR THE POTENTIAL FOR TROPICAL CYCLONE
DEVELOPMENT.
TEMPERATURES ARE EXPECTED TO RUN CLOSE TO CLIMO THROUGH THE LONG
TERM PERIODS.
&&
.AVIATION...
VFR CONDITIONS ARE GIVING WAY TO SOME TEMPO MVFR/LCL IFR...
ESPECIALLY AT PGD/FMY/RSW. ALL TERMINALS ARE EXPECTED TO SEE VCNTY
TSRA THROUGH 00/01Z...THEN VFR RETURNS. EASTERLY FLOW PREVAILS
ALTHOUGH WINDS OVERNIGHT WILL BACK AND SLACKEN SOME.
&&
.MARINE...
EASTERLY WINDS WILL CONTINUE FOR THE NEXT SEVERAL DAYS. HIGH
PRESSURE BUILDING DOWN THE EASTERN SEABOARD FROM THE MID-ATLANTIC
STATES WILL ALSO SET UP A GOOD SYNOPTIC PATTERN TO SUPPORT A
NOCTURNAL EASTERLY WIND SURGE OVER THE COASTAL WATERS. THIS SURGE IS
FORECAST TO REACH CAUTIONARY LEVELS...SHOULD BEGIN SHORTLY AFTER
SUNSET...AND BE MOST NOTABLE THE FURTHER NORTH FROM ENGLEWOOD ONE
TRAVELS. ANOTHER EASTERLY SURGE TO CAUTIONARY LEVELS CAN BE EXPECTED
WEDNESDAY NIGHT.
&&
.FIRE WEATHER...
HIGH PRESSURE TO OUR NORTH THE NEXT SEVERAL DAYS WILL KEEP A MOIST
EASTERLY FLOW OFF THE ATLANTIC A FEATURE OF THE FORECAST. RELATIVE
HUMIDITY IS EXPECTED TO REMAIN WELL ABOVE CRITICAL LEVELS THROUGH
THE NEXT SEVERAL DAYS. ONLY FIRE WEATHER CONCERN BESIDES THE
CONTINUED THREAT FOR SCATTERED AFTERNOON STORMS WILL BE HIGH
DISPERSION INDICES THAT WILL APPROACH FOR SURPASS 75 TO THE NORTH
OF I-4 THE BOTH WEDNESDAY AND THURSDAY AFTERNOONS. SOME PATCHY
GROUND FOR IS POSSIBLE LATE THE NEXT FEW NIGHTS FOR LOCATIONS THAT
RECEIVE LATE DAY RAINS...BUT NO SIGNIFICANT FOG DEVELOPMENT IS
ANTICIPATED.
&&
.HYDROLOGY...
RECENT RAINFALL HAS CAUSED ELEVATED WATER LEVELS ON MANY RIVERS AND
ACROSS THE AREA. CURRENTLY...THE LITTLE MANATEE RIVER NEAR WIMAUMA
AND THE MANATEE RIVER AT MYAKKA HEAD ARE IN ACTION STAGE...AND
ALTHOUGH WATER LEVELS ON THESE RIVERS ARE EXPECTED TO DECREASE
TODAY...ADDITIONAL RAINFALL LATER THIS WEEK MAY BRING THESE RIVERS
BACK ABOVE FLOOD STAGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 75 90 75 90 / 20 60 20 50
FMY 73 91 74 91 / 20 60 20 60
GIF 72 91 72 91 / 10 60 20 50
SRQ 74 90 74 92 / 20 60 20 50
BKV 71 91 71 91 / 20 50 20 40
SPG 77 90 77 90 / 20 60 20 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
AVIATION...RUDE
LONG TERM...JELSEMA
HYDROLOGY...LEWIS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
422 PM EDT TUE SEP 17 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 421 PM EDT TUE SEP 17 2013
17Z WV IMAGERY AND RUC ANALYSIS INDICATED A WELL-DEFINED SHORTWAVE
LIFTING NE THROUGH ERN IA. DPVA...7H FGEN AND 305K ISENTROPIC ASCENT
ASSOC WITH THE SHORTWAVE HAS SUPPORTED AN AREA OF SHOWERS OVER
NORTHEAST IA. VIS SATELLITE HAS SHOWN AN EXPANSION OF DIURNAL CU
FROM MNM-DELTA-ALGER COUNTIES EASTWARD IN AN AREA OF HIGHER
DEWPOINTS (UPPER 40 TO LOWER 50S) AIDED BY SOUTHERLY FLOW OFF LAKE
MI AND BAY OF GREEN BAY. RDGG ALOFT AND AT THE SFC HAS KEPT THE REST
OF THE FCST AREA GENERALLY CLOUD FREE THIS AFTERNOON.
TONIGHT...MDLS SUGGEST THAT AS THE IA SHRTWV GRADUALLY LIFTS TO THE
NORTHEAST...MOISTURE WILL INCREASE AND BRING SOME LIGHT WAA PCPN
INTO THE AREA AS 300K-310K ISENTROPIC ASCENT SPREADS FROM SE MN AND
WRN WI TOWARD UPPER MI. THE NAM/GFS ARE STILL A BIT MORE AGGRESSIVE
IN BRINGING SOME LIGHT PCPN INTO THE CWA COMPARED TO THE GEM/ECMWF.
GIVEN THE VERY DRY ANTECEDENT AIRMASS...THE NAM/GFS MAY BE TOO QUICK
SO USED MORE OF A MODEL BLEND FOR POPS WITH ONLY A 30 PCT CHC OF
LIGHT SHOWERS TOWARD 12Z NEAR THE WI BORDER WITH SLIGHT CHC ACROSS
MUCH OF THE REST OF THE WEST HALF.
WEDNESDAY...GIVEN PREDICTED TRACK OF ERN IA SHORTWAVE EXPECT BEST
FORCING FOR SHRA TO BE MAINLY CENTRAL COUNTIES IN THE MORNING AND
THEN TO SPREAD INTO THE EASTERN COUNTIES IN THE AFTERNOON. HAVE ONLY
SLIGHT CHC POPS FOR SHRA WEST AWAY FROM BETTER FORCING ASSOC WITH
SHORTWAVE. MODEL MLCAPES OTHER THAN NAM SHOW ONLY MARGINAL
INSTABILITY OF A FEW HUNDRED J/KG AT BEST OVER THE AREA SO WILL ONLY
INCLUDED SLIGHT CHC MENTION OF TS IN THE GRIDS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 421 PM EDT TUE SEP 17 2013
LITTLE CHANGES TO THE LARGE SCALE PATTERN FOR THE LONG TERM PERIOD
OVER THE LAST 24 HOURS. AREA WILL BE UNDER WEAK UPPER RIDGING TO
START THE PERIOD...WHICH WILL LEAD TO BROAD WARM AIR ADVECTION AND
THE POTENTIAL FOR SOME SHOWERS/THUNDERSTORMS WEDNESDAY NIGHT INTO
THURSDAY AS A WARM FRONT LIFTS ACROSS THE AREA. BEST CHANCES ON
WEDNESDAY NIGHT WILL BE EARLY ON WHEN THE STRONGEST WARM AIR
ADVECTION MOVES THROUGH AND BEFORE THE DEEPER MOISTURE STARTS TO
CUTOUT. THIS BROAD WAA WILL ALSO LEAD TO TEMPERATURES RISING TO
ABOVE NORMAL VALUES FOR WEDNESDAY NIGHT AND THURSDAY...WITH LOWS IN
THE UPPER 50S AND LOWER 60S AND HIGHS IN THE 70S TO LOWER 80S.
FINALLY FOR WEDNESDAY NIGHT...SINCE THE MODELS CONTINUE TO SHOW THE
POTENTIAL FOR LOW CLOUDS AND FOG...DID UP THE FOG TO AREAS FOR SOME
LOCATIONS IN FAVORED UPSLOPE HIGHER TERRAIN.
PRECIPITATION CHANCES WILL INCREASE HEADING INTO LATE THURSDAY
AFTERNOON AND THURSDAY NIGHT...AS THE UPPER TROUGH PUSHES NORTHEAST
THROUGH THE UPPER GREAT LAKES AND ONTARIO. AN ASSOCIATED LOW
PRESSURE SYSTEM WILL MOVE THROUGH NORTHWEST ONTARIO...BUT IT WILL
PUSH A COLD FRONT EAST ACROSS THE CWA THURSDAY NIGHT INTO FRIDAY
MORNING. ECMWF IS STILL SHOWING THE SLOWEST FRONTAL PASSAGE...WITH
THE PRECIPITATION LINGERING INTO EARLY FRIDAY AFTERNOON AS ANOTHER
WAVE RIDES UP THE FRONT. THERE CONTINUES TO BE SOME MINOR TIMING
DIFFERENCES IN THE COLD FRONT PASSAGE AND SHOWERS...BUT THE GENERAL
IDEA IS SIMILAR WITH MOST LOCATIONS LIKELY TO SEE 0.25-0.5IN OF
RAIN. AS FOR THUNDER...THERE ARE DECENT VARIATIONS IN THE
INSTABILITY...WITH SOME MODELS EVEN SHOWING UP TO 3000 J/KG OF ML
CAPE IF THERE IS ENOUGH CLEARING/HEATING IN THE AFTERNOON. 0-6KM AND
EFFECTIVE SHEAR VALUES STILL LOOK TO BE ON THE MARGINAL SIDE
(25-30KTS) ON THURSDAY AFTERNOON AND THEN INCREASE RIGHT ALONG THE
FRONTAL BOUNDARY. WOULD THINK THE BEST OPPORTUNITY FOR STRONGER
THUNDERSTORMS WOULD BE RIGHT ALONG THE FRONT AS IT MOVES INTO THE
WESTERN CWA LATE THURSDAY AFTERNOON INTO THE EVENING. AT THIS
POINT...THINK BRIEF HEAVY RAIN AND MARGINALLY SEVERE HAIL WOULD BE
THE BIGGEST THREATS IF THE UPDRAFTS CAN BE SUSTAINED.
DRIER AND COOLER AIR WILL MOVE IN RIGHT BEHIND THE FRONT AND SHOULD
LEAD TO A PERIOD OF DRY WEATHER AND EVEN SOME CLEARING FOR A FEW
HOURS. BUT MUCH COLDER AIR...WILL START TO SURGE IN WITH MORE
LOW LEVEL MOISTURE LATER FRIDAY AFTERNOON AND CONTINUE INTO THE
FIRST PART OF SATURDAY. WITH THE FLOW BEING MORE
WEST-NORTHWEST...EXPECT THE MOST CLOUDS TO BE OVER THE NORTH HALF
OF THE CWA AND WITH THE COLDER AIR THERE...EVEN SOME LAKE ENHANCED
CLOUDS (DELTA-T VALUES BETWEEN 10-14) IN THOSE WIND FAVORED AREAS.
WITH THE LATEST TRENDS OF CLOUD DEPTHS BEING 3-4KFT...SHOULD BE
ENOUGH FOR ISOLATED/SCATTERED SHOWERS AND MAY NEED TO ADJUST POPS A
LITTLE HIGHER OVER THE COMING SHIFTS.
THE UPPER TROUGH WILL LIFT NORTHEAST ON SATURDAY NIGHT AND ALLOW
UPPER RIDGING AND HIGH PRESSURE TO BUILD INTO THE AREA FOR SUNDAY.
THUS...EXPECT A DRY SECOND HALF OF THE WEEKEND...ALTHOUGH
TEMPERATURES WON/T WARM UP TOO SIGNIFICANTLY (WITH HIGHS AROUND 60).
ALSO...SATURDAY NIGHT COULD SEE SOME FROST OVER THE INTERIOR WEST
WHERE SKIES BEGIN TO CLEAR AND WINDS LET UP DUE TO THE APPROACHING
HIGH.
THIS HIGH WILL QUICKLY SHIFT EAST-NORTHEAST INTO QUEBEC ON
MONDAY...AS THE AREA IS UNDER THE UPPER RIDGE AXIS. STILL EXPECT
MONDAY TO BE DRY AND MUCH WARMER (HIGHS IN THE MID-UPPER 60S)...BUT
THE NEXT UPPER TROUGH IS LURKING TO THE WEST. THIS UPPER TROUGH
LOOKS TO GIVE A GLANCING BLOW TO THE CWA ON MONDAY NIGHT INTO
TUESDAY AND WILL HIGHLIGHT THE BEST POPS OVER THE NORTHWESTERN HALF
OF THE CWA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 201 PM EDT TUE SEP 17 2013
WITH DRY HIGH PRES DOMINATING...VFR CONDITIONS WILL BE THE RULE FOR
ALL TAF SITES THROUGH THIS EVENING. A STRENGTHENING SOUTHERLY PRES
GRAD JUST ABV DEVELOPING RADIATION INVERSION WILL RESULT IN LLWS
TONIGHT AT TAF SITES. LATE TONIGHT...INCREASING LOW LEVEL MOISTURE
MOVING NORTHWARD FROM WI AHEAD OF AN ADVANCING SYSTEM OVER THE
CENTRAL PLAINS IS EXPECTED TO BRING MVFR CIGS INTO THE TAF SITES LATE
TONIGHT INTO MIDDAY WEDNESDAY. KSAW WILL HAVE THE BEST CHC OF
PREVAILING SHRA CLOSER TO THE BEST FORCING FROM THE SYSTEM WHILE KIWD
AND KCMX SHOULD ONLY SEE VCSH
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 421 PM EDT TUE SEP 17 2013
BETWEEN HIGH TO THE EAST AND LOW PRES OVER THE PLAINS...SRLY WINDS
WILL REMAIN UP TO 20 KNOTS INTO WED. WINDS SHOULD THEN REMAIN BELOW
20 KNOTS UNTIL LATE THU NIGHT AND FRI WHEN A COLD FRONT MOVES
THROUGH THE REGION AND BRINGS W TO NW WINDS UP TO 30 KNOTS FRI INTO
SAT. WINDS WILL DECREASE BLO 20 KT BY SUNDAY AS HIGH PRESSURE BUILDS
IN FM THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
215 PM EDT TUE SEP 17 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 508 AM EDT TUE SEP 17 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM
IL/WI INTO NW ONTARIO. AT THE SFC...A RIDGE WAS LOCATED OVER THE ERN
GREAT LAKES RESULTING IN SRLY THROUGH THE UPPER MS VALLEY INTO THE
WRN CWA. THE COMBINATION OF WAA AND A WEAK UPSTREAM SHORTWAVE TROUGH
OVER IA SUPPORTED AN AREA OF LIGHT SHOWERS FROM ERN NEB INTO NW IA.
OTHERWISE...IR LOOP INDICATED CLEAR SKIES OVER THE NRN GREAT LAKES.
TODAY...HIGH PRES AND THE LINGERING DRY AIRMASS WILL CONTINUE TO
DOMINATE THE WEATHER WITH MOSTLY SUNNY SKIES OVER UPPER MI. MIXING
TO AROUND 900-875 MB (AROUND 11C) WILL RESULT IN MAX READINGS IN THE
MID TO UPPER 60S.
TONIGHT...MDLS SUGGEST THAT AS THE IA SHRTWV GRADUALLY LIFTS TO THE
NORTHEAST...MOISTURE WILL INCREASE AND SOME LIGHT WAA PCPN WITH AREA
OF 300K-310K ISENTROPIC LIFT WILL SPREAD FROM SE MN AND WRN WI
TOWARD UPPER MI. THE NAM/GFS WERE A BIT MORE AGGRESSIVE IN BRINGING
SOME LIGHT PCPN INTO THE CWA COMPARED TO THE GEM/ECMWF. GIVEN THE
VERY DRY ANTECEDENT AIRMASS...THE FCST LEANS MORE TOWARD THE SLOWER
ONSET OF PCPN WITH ONLY A SLIGHT CHANCE OF LIGHT SHOWERS TOWARD 12Z
NEAR THE WI BORDER.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 447 AM EDT TUE SEP 17 2013
WED THROUGH MOST OF THU...A LOW PRESSURE SYSTEM CURRENTLY OFF THE
PACIFIC NW CONUS WILL DEEPEN WHILE MOVING FROM MT AT 12Z WED TO THE
CENTRAL SASKATCHEWAN/ONTARIO BORDER BY 00Z FRI. WILL DISCUSS PRECIP
ALONG THE COLD FRONT THAT MOVES IN LATE THU MOMENTARILY...BUT BEFORE
THAT MOVES IN EXPECT JUST SOME MINOR PRECIP. BEST CHANCE FOR PRECIP
LOOKS TO BE WITH BROAD WAA AHEAD OF THE SYSTEM...SO SOME LIGHT
PRECIP IS DIFFICULT TO FORECAST. HOWEVER...AGREE WITH PREVIOUS SHIFT
THAT SLIGHT CHANCE TO LOW CHANCE POPS SEEM WARRANTED PRIOR TO COLD
FROPA. HIGHS WED LOOK TO BE AROUND 70 WITH 850MB TEMPS OF 10-14C.
THU TEMPS LOOKS MORE CONDITIONAL AS LOW CLOUDS MAY INHIBIT MIXING OF
14-19C 850MB TEMPS...BUT COULD SEE HIGHS IN THE MID 70S IF ENOUGH
CLEARING OCCURS.
NOW FOR THE PROMISED DISCUSSION OF PRECIP ALONG THE COLD FRONT. THE
LOW WILL CONTINUE DEEPENING AS IT MOVES TO HUDSON BAY BY 00Z
SAT...THEN REMAINS NEARLY STATIONARY WHILE OCCLUDING THROUGH THE
REST OF SAT. WHILE DISCUSSING THE TRACK/TIMING OF THE SYSTEM...LET
IT BE SAID THAT MODELS ARE DOING MUCH BETTER THAN 24 HOURS
AGO...BOTH WITH RUN TO RUN CONTINUITY AND WITH MODEL TO MODEL
AGREEMENT. STILL THINK THERE WILL BE SHIFTS IN THE TRACK/TIMING BY
THE MODELS OVER THE NEXT FEW RUNS...BUT SHOULD AT LEAST BE GETTING A
BETTER IDEA OF WHAT THE SYSTEM WILL DO. THE COLD FRONT TIMING IS
ALSO SIMILAR BETWEEN MODEL RUNS...AT LEAST RELATIVELY SO FOR THIS
TYPE OF SYSTEM...WITH THE FRONT MOVING INTO THE FAR WRN CWA AROUND
00Z FRI...THEN TO THE CENTRAL CWA AROUND 12Z FRI AND TO THE ERN CWA
BY 18Z FRI. EXPECT A LINE OF SHOWERS AND THUNDERSTORMS TO MOVE
ACROSS THE CWA MAINLY THU NIGHT...AND AGREE WITH PREVIOUS SHIFT THAT
LIKELY POPS ARE JUSTIFIED. DRY SLOT MOVES IN BEHIND THE
FRONT...WHICH SHOULD BRING AN END TO SYNOPTIC PRECIP AS THE
MID/UPPER LEVELS DRY OUT. HOWEVER...WRAP AROUND MOISTURE WILL STILL
BE PRESENT IN THE LOW LEVELS AS THE UPPER TROUGH MOVES OVERHEAD FRI
INTO FRI NIGHT WITH 850MB TEMPS AS LOW AS 1C THROUGH 00Z FRI AND AS
LOW AS -2C FRI NIGHT. WLY LOW LEVEL WINDS MEANS THE W WIND LAKE
EFFECT/UPSLOPE BELTS WILL SEE THE BEST CHANCES FOR RAIN BEHIND THE
FRONT FRI AND FRI NIGHT.
MODELS DO START TO VARY MORE WITH HOW LONG TO LINGER THE UPPER
TROUGH OVER THE AREA SAT AND HOW QUICK TO BRING IN AN UPPER RIDGE
FROM THE W. THE GFS IS SLOWER WITH THE TROUGH AND HAS 850MB TEMPS
AROUND -2C AT 00Z SUN WHILE THE ECMWF HAS 850MB TEMPS OF 2-8C AT THE
SAME TIME. THEREFORE...HAVE LITTLE CONFIDENCE IN TEMPS FOR SAT. WITH
SUCH A SPREAD IN LOW LEVEL TEMPS...THERE IS ALSO A SPREAD IN
POSSIBILITIES FOR LAKE EFFECT RAIN...SO WILL CONTINUE TO HAVE SLIGHT
CHANCE IN THE FORECAST.
SUN SHOULD SEE A WARM UP AS THE UPPER RIDGE MOVES OVERHEAD...BUT
STILL NOT VERY CONFIDENT ON EXACT TEMPS FOR THE DAY GIVEN CONTINUED
MODEL SPREAD...BUT AT LEAST SHOULD BE WARMER AND DRIER THAN SAT.
MON SHOULD AGAIN SEE WARMING TEMPS AS SLY FLOW INCREASES AHEAD OF
THE NEXT LOW PRESSURE SYSTEM DEVELOPING OVER THE PLAINS. .
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 201 PM EDT TUE SEP 17 2013
WITH DRY HIGH PRES DOMINATING...VFR CONDITIONS WILL BE THE RULE FOR
ALL TAF SITES THROUGH THIS EVENING. A STRENGTHENING SOUTHERLY PRES
GRAD JUST ABV DEVELOPING RADIATION INVERSION WILL RESULT IN LLWS
TONIGHT AT TAF SITES. LATE TONIGHT...INCREASING LOW LEVEL MOISTURE
MOVING NORTHWARD FROM WI AHEAD OF AN ADVANCING SYSTEM OVER THE
CENTRAL PLAINS IS EXPECTED TO BRING MVFR CIGS INTO THE TAF SITES LATE
TONIGHT INTO MIDDAY WEDNESDAY. KSAW WILL HAVE THE BEST CHC OF
PREVAILING SHRA CLOSER TO THE BEST FORCING FROM THE SYSTEM WHILE KIWD
AND KCMX SHOULD ONLY SEE VCSH &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EDT TUE SEP 17 2013
AS THE HIGH SHIFTS TO THE EAST...SRLY WINDS UP TO 20 KNOTS ARE
EXPECTED FROM TODAY INTO WED. WINDS SHOULD THEN REMAIN BELOW 20
KNOTS UNTIL FRI WHEN A COLD FRONT MOVES THROUGH THE REGION AND
BRINGS W TO NW WINDS UP TO 30 KNOTS FRI INTO SAT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...VOSS
MARINE...JLB
AREA FORECAST DISCUSSION
NWS DULUTH MN
319 PM CDT TUE SEP 17 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 318 PM CDT TUE SEP 17 2013
MOISTURE CONTINUED TO INCREASE FROM WEST TO EAST ACROSS THE
NORTHLAND TODAY. THE HIGH TO THE EAST WAS LOSING IT`S GRIP ON THE
NORTHLAND. A SHORTWAVE WAS MOVING NORTHEAST OUT OF IOWA AND WILL
COMBINE WITH WAA/MOISTURE ADVECTION TO CAUSE CLOUDS TO THICKEN ALL
AREAS TONIGHT AND BRING A CHANCE FOR RAIN. THE RAP WAS DOING A
GOOD JOB DEPICTING THE CLOUDS OVER OUR WESTERN CWA AND THEY SHOW
INCREASING HUMIDITY ACROSS MUCH OF THE AREA BY 06Z. RAIN WILL BE
POSSIBLE TONIGHT...AND WE INCREASED POPS OVER OUR FAR SOUTHERN CWA
WHICH WILL HAVE THE BEST CHANCE AT SEEING UP TO A TENTH OF AN INCH
OVERNIGHT. PWAT VALUES ARE EXPECTED TO RISE TO 1 TO 1.4 INCHES
OVERNIGHT...AND WE EXPECT AREAS OF FOG TO FORM. MOST AREAS SHOULD
NOT EXPERIENCE DENSE FOG...WITH THE EXCEPTION OF AREAS AROUND LAKE
SUPERIOR LATE TONIGHT WHICH COULD SEE SOME PATCHY DENSE FOG. SURFACE
DEWPOINTS ARE EXPECTED TO RISE INTO THE FIFTIES...AND WERE ALREADY
50 TO 55 FROM KINL TO KGPZ TO KAIT AND POINTS WEST. WE KEPT THE
MENTION OF DRIZZLE TONIGHT FOR MOST AREAS...ALTHOUGH WE DON`T
THINK IT WILL BE WIDESPREAD GIVEN UPSTREAM CONDITIONS. AREAS
AROUND THE LAKE WILL HAVE A BETTER CHANCE AND IT COULD BE
WIDESPREAD LATE TONIGHT INTO WEDNESDAY MORNING.
STABILITY GRADUALLY LOWERS TONIGHT...AND WE ADDED A SLIGHT CHANCE
FOR A THUNDERSTORM ACROSS THE SOUTH LATE. WAA WILL CONTINUE
WEDNESDAY...WITH A SHORTWAVE RIDGE ALOFT MOVING THROUGH EARLY.
WE HAVE A CHANCE FOR MORE SHOWERS/STORMS OVER ALL BUT FAR
NORTHWEST AREAS ON WEDNESDAY...WITH THE BEST CHANCE OCCURRING
EARLY. CLOUDS WILL SLOWLY DIMINISH OVER WESTERN AREAS...BUT
SHOULD REMAIN THROUGH MOST OF THE DAY AROUND LAKE SUPERIOR AND
OVER NORTHWEST WISCONSIN. HIGHS WILL RANGE FROM THE MID SIXTIES TO
MID SEVENTIES ACROSS THE NORTHLAND...WARMEST SOUTHWEST...COOLEST
AROUND LAKE SUPERIOR.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 318 PM CDT TUE SEP 17 2013
THE FIRST FEW DAYS OF THIS PERIOD WILL BE STORMY AND WET THEN BECOME
CHILLY WITH A STRONG COLD FRONTAL PASSAGE.
STRONG WAA THAT WILL BE ONGOING AHEAD OF AN APPROACHING COLD FRONT
WILL CONTINUE CLOUDS WEDNESDAY NIGHT. KEPT IN CHANCE OF SHOWERS
AND THUNDERSTORMS WEDNESDAY NIGHT...BUT VERY WARM MID LEVEL TEMPS
MAY PROHIBIT STORM FORMATION. BOTH THE NAM AND GFS SHOW SURGE OF 7H
10+C TEMPS. MUCH BETTER CHANCE OF THUNDERSTORMS WILL BE THURSDAY AS
A STRONG COLD FRONT APPROACHES THE AREA FROM THE WEST. THE NAM MAY BE
A BIT FASTER...BUT THE MODELS ARE IN PRETTY GOOD AGREEMENT WITH
MOVEMENT OF THE FRONT AND RESULTING QPF. DURING THE DAY THE
ATMOSPHERE DESTABILIZES IN THE STRONG WAA REGIME AND WILL BE PRIMED
FOR STORMS WHEN THE FRONT ARRIVES IN THE AFTERNOON/EARLY EVENING
EVENING. LIL`S FORECAST DOWN TO -6 AND MUCAPES UP TO 2500 J/KG. AN
EXTRA BOOST OF LIFT WILL BE PROVIDED BY AN UPPER LEVEL JET AND
S/WV.
STRONG COLD AIR WILL STREAM INTO THE REGION BEHIND THE FRONT FOR THE
FRIDAY...BUT AS HIGH PRESSURE BUILDS INTO THE REGION THE WEEKEND
WILL HAVE SUNSHINE BUT COOLER TEMPS. THIS WILL BE FOLLOWED BY
ANOTHER LOW PRESSURE/COLD FRONT ON FROM EARLY THROUGH MID WEEK WITH
A STRONG UPPER LEVEL TROF/CLOSED LOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1229 PM CDT TUE SEP 17 2013
MVFR CIGS WILL CONTINUE TO COVER THE WESTERN PART OF THE FORECAST
AREA THIS AFTERNOON....AND THESE CLOUDS WILL SPREAD ACROSS THE
REST OF THE AREA LATE THIS AFTERNOON AND EARLY EVENING. AFTER
SUNSET CIGS WILL LOWER CONSIDERABLY AND MUCH OF THE AREA WILL BE
IN IFR CONDITIONS..MAINLY DUE TO CIGS. HOWEVER...LATE TONIGHT AS MORE
MOISTURE SURGES INTO THE AREA...PATCHY DENSE FOG AND RAIN WILL
DEVELOP.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 53 65 62 74 / 20 20 50 70
INL 54 74 60 71 / 10 10 50 60
BRD 58 77 65 74 / 20 20 50 60
HYR 54 73 62 76 / 40 40 40 70
ASX 54 71 59 78 / 30 30 40 70
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...MELDE
LONG TERM...CLC
AVIATION...CLC
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1258 PM CDT Tue Sep 17 2013
.SHORT TERM: (Through Late This Afternoon)
Issued at 303 AM CDT Tue Sep 17 2013
Synoptic pattern over the region today will be dominated by broad
WAA overrunning the cooler Canadian airmass that backed into the
area Monday and overnight, which should certainly generate showers
and a few thunderstorms today in the northwest half of the CWA.
However, other than lead shortwave responsible for the light echoes
in se MO attm (which is outrunning better moisture) and some 850mb
theta-e advection vaguely focused over our n counties this morning,
mechanisms for precip are rather ill-defined. The lack of a
well-defined precip structure in the early morning regional radar
imagery is indicating the rather diffuse nature of the lift.
Plan to maintain broad PoP trends in current forecast with likely
POPS in our northwest counties to chance PoPs in se MO, although
specific numbers in a few locations will be changing to reflect
latest radar trends. In our e counties couldn`t rule out a few
sprinkles early today, but chances of measurable precip here look
low attm. Will make a last minute call on this.
Other concern for today is how warm to go on high temperatures, as
residual cool air and scattered showers will at least partially
offset warming due to the WAA. Still working on specifics but most
areas should remain in the 70s, with the coolest temps over the
northwest counties where clouds will be thickest and threat of
showers should be highest.
Truett
.LONG TERM: (Tonight through Monday)
Issued at 303 AM CDT Tue Sep 17 2013
Isolated to scattered SHRA/TSRA may continue percolating tonight due
to isentropic ascent along the 300-305 K surface, with the highest
precip chances across northeast MO and west central IL. Once the
second of two shortwaves (which were located over KS and OK early
this morning) and a warm front finally lift northeastward tonight,
precipitation should also lift away from the area.
Early morning water vapor imagery along and recent RUC 1.5 PVU
analyses depicted a strong vort max located just off the northern
CA coast. This feature is forecast to cross the Rockies and induce
surface cyclogenesis over SD/ND tomorrow, although it will also
influence conditions over MO/IL by producing weakly diffluent
southwesterly flow aloft. Between general moistening of the air
mass (PW values rise to around 1.7 inches by Wed night),
increasing H7-H5 lapse rates, and nocturnal LLJ activity, it`s
hard to rule out disorganized iso-sct precip for Wed and Wed
night, particularly across the northern and northeastern CWA. In
terms of the aforementioned low pressure system which will be
moving along the US/Canadian border and into southern Canada by
Thu night, models remain in general agreement with the overall
pattern despite some differences after 20/00z regarding a piece of
energy that breaks off near the base of the trough and then moves
across MO on Fri night. The cold front is forecast to approach the
CWA on Thu night and then move through on Fri/Fri night. Low level
convergence with the front, large scale ascent ahead of the upper
level trough axis, and favorable positioning beneath the right
entrance region of a jet at H25 all support likely PoPs for Thu
night and Fri across parts of the CWA. Precipitation is expected
to end from northwest to southeast due to post-frontal subsidence.
17/00z runs of the ECMWF/GFS/GEM all agree that a surface high
pressure center will build into the Great Lakes this weekend and
that there will be some degree of upper ridging over the Plains
ahead of the next progressive trough near the West Coast, but each
model has a different take on the upper level pattern east of the
Mississippi River with potential impacts for the MO/IL forecast.
The GFS depicts a closed low over the OH valley, the GEM brings a
tropical low northward from the Gulf of Mexico, and the ECMWF has
a weak upper trough axis oriented from LA through GA and into VA.
Since there is little confidence in any particular solution at
this time, the forecast grids for Sat-Mon generally reflect the
recommended CR initialization.
Kanofsky
&&
.AVIATION: (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1241 PM CDT Tue Sep 17 2013
Area of rain and lower CIGS/VSBYS over central Missouri will
continue to spread into parts of eastern/northeast Missouri and
west central Illinois. Not expecting flight conditions to fall
below MVFR as the precipitation continues to weaken, but CIGS will
likely occasionally fall below 2000FT. Expecting the weakening
trend to continue through the weekend with little or no precip
crossing the Mississippi river into southwest Illinois. Should see
CIGS rise above 3000FT later this afternoon into the evening.
Another wave of showers is expected to develop late tonight which
could bring flight conditions back down to MVFR for early
Wednesday morning.
Specifics for KSTL:
The area of rain over central Missouri is expected to continue
weakening this afternoon, so am expecting little if any
precipitation to reach Lambert. Should see VFR flight conditions
continue at least through 06Z-08Z. However, another batch of rain
is expected to develop over central Missouri late tonight, and
this may bring CIGS down after 09Z. Confidence is low however, so
have not lowered CIGS substantially in the TAF. Expect that if the
CIGS do drop below VFR, conditions should improve after 12Z-14Z
Wednesday.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
315 PM CDT TUE SEP 17 2013
.DISCUSSION...
SHORT TERM CONCERNS ARE MAINLY CLOUD COVER INTO WEDNESDAY MORNING
AND TEMPERATURES THE NEXT FEW DAYS.
12Z UPPER AIR CHARTS SHOWED THE FOLLOWING. AT 300 MB...JETSTREAM
AXIS EXTENDED FROM BASE OF THE TROUGH RIGHT ALONG THE WEST COAST
NORTHEASTWARD ACROSS THE ROCKIES AND INTO MANITOBA. AT 500 MB...ONE
AREA OF GREATER THAN 30 METER HEIGHT FALLS EXTENDED FROM CANADA DOWN
INTO MO. MORE SIGNIFICANT FALLS (60-90 METERS) WERE JUST AHEAD OF
THE TROUGH OVER NORTHERN CA...SOUTHERN OR AND INTO NV. DECENT
MOISTURE WAS NOTED FROM NRN MEXICO UP INTO THE CENTRAL PLAINS AT
AND BELOW 700 MB. EARLY AFTN WATER VAPOR IMAGERY SHOWED DRYING
MOVING ACROSS THE PLAINS BETWEEN THE TWO SHORTWAVES. EARLY AFTN
SURFACE ANALYSIS SHOWED MODEST SOUTHERLY FLOW IN PLACE OVER THE
AREA WITH DEWPOINTS IN THE 50S AND 60S.
TONIGHT...EXPECT SOME DECREASE IN OVERALL CLOUD COVER. FORECAST
SOUNDINGS SHOW SOME ELEVATED INSTABILITY THIS EVENING ALONG WITH
DECENT MID LEVEL LAPSE RATES. LATEST RUNS OF THE RAP DEVELOP SOME
PCPN ACROSS ABOUT THE EASTERN 1/2 OF MY AREA. 12Z GFS DID TOO.
SO WILL INCLUDE A SMALL CHANCE FOR TSTMS PRIOR TO 09Z. WITH
SUBSTANTIAL LOW LEVEL MOISTURE REMAINING IN PLACE AFTER HIGHER
CLOUDS CLEAR OUT...HAVE SOME CONCERN THAT STRATUS MAY REFORM. WE
MAY ALSO HAVE SOME FOG BUT IT APPEARS TO BE LESS OF A CONCERN FOR
THE PUBLIC FORECAST DUE TO WINDS MOSTLY ABOVE 7 KNOTS.
WEDNESDAY...SOUTHERLY FLOW WILL INCREASE AS MIXING DEPTH INCREASES
THROUGH THE MORNING...WITH BREEZY/WINDY CONDITIONS BY AFTN. 850 MB
TEMPERATURES WILL INCREASE SUBSTANTIALLY COMPARED TO TODAY (INTO THE
19-22 DEGREE CELSIUS RANGE BY 00Z THURSDAY)...SO HIGHS IN THE
UPPER 80S TO AROUND 90 SEEM LIKELY.
SYSTEM FOR WEDNESDAY NIGHT INTO THURSDAY SEEMS TO HAVE SLOWED DOWN A
BIT SO DID MAKE SOME ADJUSTMENTS FOR PCPN TIMING IN THOSE PERIODS.
COLD FRONT SHOULD ENTER OUR FAR NORTHWEST COUNTIES BETWEEN 06Z AND
09Z THURSDAY THEN EXIT THE SOUTHEAST COUNTIES BETWEEN 21Z THURSDAY
AND 00Z FRIDAY. BOOSTED PCPN CHANCES A BIT FOR THURSDAY...BUT IT NOW
APPEARS THE SYSTEM WILL EXIT SOONER THURSDAY NIGHT BASED ON A BLEND
OF GFS/NAM/SREF/ECMWF/GEM.
THE PERIOD FROM FRIDAY THROUGH SUNDAY SHOULD BE DRY...WITH HIGHS IN
THE 70S TO AROUND 80. 500 MB TROUGH WILL BE SHIFTING EAST OF THE
AREA FRIDAY...WITH RIDGING OVER THE ROCKIES AND ANOTHER TROUGH OFF
THE WEST COAST. FLOW WILL BE PROGRESSIVE IN THIS PERIOD...WITH THE
NEXT CHANCE OF PCPN MOVING IN BY SUNDAY NIGHT AS THE SYSTEM DIGS
OVER THE ROCKIES. DIFLUENT FLOW ALONG WITH INCREASING MOISTURE
AHEAD OF THE NEXT COLD FRONT SHOULD BRING SOME SHOWERS AND TSTMS
FROM SUNDAY NIGHT THROUGH MONDAY NIGHT.
MILLER
&&
.AVIATION...
18Z TAFS FOR KOMA...KLNK...AND KOFK.
IFR CONDITIONS CONTINUE ACROSS THE TAF SITES THIS AFTERNOON.
SHOWERS HAVE CLEARED THE SITES...BUT CEILINGS ARE SLOW TO IMPROVE
TODAY AS LOW-LEVEL MOISTURE LINGERS. INCREASED SOUTHERLY FLOW
SHOULD HELP ERODE STRATUS DECK FROM THE WEST AND THE SOUTH FROM
LATE AFTERNOON INTO THIS EVENING...BUT CANNOT RULE OUT THE
POSSIBILITY THAT THE STRATUS DECK WILL SOCK IN LONGER THAN CURRENT
FORECAST INDICATES. WINDS WILL REMAIN AROUND 10-12KT
OVERNIGHT...WHICH SHOULD BE ENOUGH TO HELP ALLEVIATE WIND SHEAR
CONCERNS...AND WHICH ALSO SHOULD BE ENOUGH TO DETER FOG FORMATION.
EVEN SO...HAVE INCLUDED AN MVFR VIS GROUP AT ALL SITES LATE
TONIGHT AS CLEARING OCCURS...AS GUIDANCE IS UNANIMOUSLY INDICATING
AT LEAST SOME EXTENT OF REDUCED VIS. VIS WILL IMPROVE AS WINDS
INCREASE THROUGH THE MORNING...WITH GUSTY SOUTH WINDS DEVELOPING
BY MID-MORNING.
MAYES
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1233 PM CDT TUE SEP 17 2013
.UPDATE...
ISSUED AT 1226 PM CDT TUE SEP 17 2013
SOLID SC CLOUD DECK CONTINUES TO OVERSPREAD FA EARLY THIS
AFTERNOON. CLOUDS STILL LOOK FAIRLY SOLID WITH NO BREAKS AT THIS
POINT. BASED ON CURRENT TEMPERATURE TRENDS WILL NEED TO LOWER
MAXIMUM TEMPERATURES SEVERAL DEGREES ACROSS THE BOARD AND STILL
HOPE CIGS BREAK ENOUGH FOR SOME LATE AFTERNOON SOLAR. NO OTHER
CHANGES PLANNED.
UPDATE ISSUED AT 931 AM CDT TUE SEP 17 2013
MADE SOME SLIGHT CLOUD TREND ADJUSTMENTS BASED ON CURRENT
SATELLITE TRENDS OTHERWISE CURRENT FORECAST LOOKING GOOD SO FAR
AND NO OTHER CHANGES MADE.
UPDATE ISSUED AT 656 AM CDT TUE SEP 17 2013
LEADING EDGE OF LOW CLOUDS IS NOW ALONG A COOPERSTOWN TO WAHPETON
LINE AND CONTINUES TO MOVE NORTH-NORTHEAST AROUND 35 MPH. BACK EDGE
OF CLOUD DECK IS A BIT FARTHER WEST THAN PREVIOUS FORECAST...SO
ADJUSTED SKY GRIDS TO REFLECT LATEST OBSERVATIONS. AS A RESULT...
EXPECT ALL BUT THE FAR NORTHWEST FORECAST AREA TO BECOME MOSTLY
CLOUDY BY LATE MORNING INTO THE EARLY AFTERNOON. LATEST HRRR
SUGGESTS THE SUN MAY PEAK OUT FOR A COUPLE HOURS ALONG THE VALLEY
FLOOR BEFORE SUNSET. OTHERWISE...AREAS TO THE EAST WILL REMAIN
CLOUDY FOR MUCH OF THE NIGHT. ALSO DECREASED TEMPERATURES A FEW
DEGREES ACROSS THE NORTHERN VALLEY INTO NORTHWEST MN TO ACCOUNT
FOR MORE EXPANSIVE CLOUDS. REST OF THE FORECAST IN GOOD SHAPE WITH
NO MAJOR CHANGES AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 414 AM CDT TUE SEP 17 2013
CHALLENGES INCLUDE CLOUD COVER AND TEMPERATURES TODAY/TONIGHT AND
THEN PRECIPITATION CHANCES/SEVERE POTENTIAL WEDNESDAY NIGHT INTO
THURSDAY. GFS/NAM/ECMWF/GEM IN GOOD OVERALL AGREEMENT AND WILL
USE A BLENDED SOLUTION FOR THIS FORECAST PACKAGE.
FOR TODAY...MOIST SOUTHERLY FLOW BETWEEN THE SURFACE HIGH ACROSS
THE GREAT LAKES AND DEVELOPING LOW IN THE LEE OF THE NORTHERN ROCKIES
WILL ADVECT LOW CLOUDS CURRENTLY ACROSS EASTERN SD/SOUTHERN MN/
NE/IA NORTHWARD ACROSS THE FORECAST AREA. RAP 925 HPA RH SUGGESTS
THESE CLOUDS WILL MOVE INTO THE SOUTHERN FORECAST AREA BY 12 UTC
AND THEN ALONG AND EAST OF THE VALLEY BY THIS AFTERNOON. AREAS
WITH PERSISTENT CLOUD COVER NOT LIKELY TO RISE ABOVE 70 DEGREES.
LOWER TO MID 70S ARE POSSIBLE ACROSS THE DEVILS LAKE BASIN AND
NORTHERN VALLEY WHERE MORE SUNSHINE IS EXPECTED. TODAY WILL ALSO
BE BREEZY TO LOCALLY WINDY WITH 30 KTS IN THE MIXED LAYER. THIS
SHOULD TRANSLATE TO SURFACE WINDS FROM 15 TO 25 MPH WITH GUSTS UP
TO 30 MPH.
LOW CLOUDS WILL BE VERY SLOW TO DISSIPATE OVERNIGHT...ESPECIALLY
ACROSS THE EASTERN FORECAST AREA. MODEL SOUNDINGS SUGGEST THE
POSSIBILITY OF SOME LIGHT DRIZZLE...BUT GIVEN LOW SENSIBLE WEATHER
IMPACT AND COVERAGE UNCERTAINTY...WILL NOT INCLUDE IN CURRENT
GRIDS. SOUTHERLY WINDS WILL REMAIN ELEVATED BETWEEN 10 AND 15
MPH WITH LOW TEMPERATURES GENERALLY IN THE 50S.
STRONG POSITIVE THERMAL ADVECTION IN THE WARM SECTOR OF AN
APPROACHING PACIFIC WAVE WILL RESULT IN TEMPERATURES WELL ABOVE
NORMAL ON WEDNESDAY. AFTERNOON HIGHS WILL CLIMB INTO THE MID 70S
TO LOWER 80S. SOUTHERLY WIND WILL NOT BE AS STRONG AS TODAY. MOST
OF THE DAY SHOULD BE DRY WITH ONLY A CHANCE FOR AFTERNOON SHOWERS
AND THUNDERSTORMS ACROSS THE DEVILS LAKE BASIN.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 414 AM CDT TUE SEP 17 2013
A STRONG SURFACE LOW WILL TRACK ACROSS ND WEDNESDAY EVENING AND
INTO THE CENTRAL/NORTHERN VALLEY BY 06 UTC THURSDAY. WARM
TEMPERATURES ALOFT MAY LIMIT CONVECTIVE INITIATION...BUT THE
COMBINATION OF MLCAPE UP TO 2000 J/KG...PWATS AROUND 1.5 INCHES...
AN APPROACHING SURFACE COLD FRONT AND INCREASING BULK SHEAR FROM A
300 HPA JET STREAK SHOULD RESULT IN THUNDERSTORM DEVELOPMENT
ACROSS EASTERN ND INTO NORTHWEST MN. SOME STORMS NEAREST TO THE
SURFACE LOW MAY BECOME SEVERE AND THIS IS HIGHLIGHTED IN THE SPC
DAY 2 CONVECTIVE OUTLOOK WHICH SHOWS A SLIGHT RISK ALONG AND
NORTHWEST OF A LINE FROM CARRINGTON TO GRAND FORKS TO HALLOCK.
TOO EARLY TO ADD SEVERE WORDING TO THE GRIDS...BUT SOMETHING TO
WATCH.
WITH THE EXCEPTION OF SOME WRAP-AROUND SHOWERS LATE WEDNESDAY
NIGHT INTO THURSDAY ACROSS THE NORTHERN FORECAST AREA...MOST OF
EASTERN ND/NORTHWEST MN WILL BE DRY-SLOTTED ONCE CONVECTION MOVES
INTO CENTRAL AND EAST CENTRAL MN BY 12 UTC THURSDAY. STRONG
WESTERLY WINDS WILL FOLLOW IN THE WAKE OF THE SURFACE FRONT...
ALONG WITH A MUCH COOLER AIR MASS. HIGH TEMPERATURES THURSDAY WILL
RANGE FROM THE LOW 60S ACROSS THE DEVILS LAKE BASIN TO THE LOW 70S
ACROSS WEST CENTRAL MN LAKES COUNTRY. WEST WINDS WILL RANGE FROM
15 TO 25 MPH.
FRIDAY THROUGH MONDAY...THE WEEK WILL END QUIET AND COOL WITH
NORTHWESTERLY FLOW BEHIND THE DEPARTING TROUGH AND HIGH PRESSURE
BUILDING INTO THE PLAINS. A FEW SHOWERS MAY LINGER OVER LAKE OF THE
WOODS AREA BUT OTHERWISE THINK WE WILL BE DRY THROUGH FRIDAY AND
INTO SATURDAY. THE WEEKEND WILL SEE A SLOW WARMING TREND AS
SOUTHERLY WINDS RETURN. THE MAIN UPPER TROUGH WILL REMAIN OVER THE
WESTERN CONUS THROUGH THE END OF THE PERIOD BUT MODELS ALL SHOW
SIGNS OF A LEAD SHORTWAVE MOVING FROM THE NORTHERN ROCKIES THROUGH
THE PLAINS LATE SUNDAY AND INTO MONDAY. KEPT FAIRLY HIGH POPS GOING
FOR SUNDAY NIGHT AND MONDAY AS A WEAK SFC TROUGH AXIS/FRONTAL
BOUNDARY MOVES THROUGH. TEMPS WILL BE A FEW DEGREES LOWER ON MONDAY
BUT STILL AROUND SEASONAL AVERAGES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1226 PM CDT TUE SEP 17 2013
MVFR CIGS EXPECTED TO IMPACT ALL TAF SITES FOR THE REMAINDER OF THE
AFTERNOON AND INTO THE EVENING WITH A SLOW EROSION OF THE STRATUS
DECK FROM WEST TO EAST. GUSTY SOUTHERLY WINDS WILL DIMINISH THIS
EVENING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...ROGERS
LONG TERM...ROGERS/JR
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1214 PM CDT TUE SEP 17 2013
.DISCUSSION...
SEE 18Z AVIATION DISCUSSION.
&&
.AVIATION...
RAP AND HRRR KEEP THINGS KIND OF DRY THIS AFTN WITH JUST SOME
SPOTTY SHOWERS EXPECTED OVER THE SOUTHWEST THIRD OF THE REGION AND
OVER THE EXTREME NE PART OF THE AREA. STRONGER WINDS JUST OFF THE
SURFACE ARE MIXING DOWN SO ADDED WIND GUSTS FOR THIS AFTN. MODELS
HINT AT SOME MID LEVEL CLOUDS SCOOTING ACROSS THE AREA OVERNIGHT.
TOMORROW LOOKS SIMILAR TO TODAY WITH SCT CLOUDS BENEATH A CANOPY
OF BKN CIRRUS. 43
&&
.PREV DISCUSSION... /ISSUED 1028 AM CDT TUE SEP 17 2013/
UPDATE...
VERY LITTLE -SHRA ACTIVITY THIS MORNING...ANY MAINLY CONFINED TO
THE COASTAL COUNTIES SURROUNDING MATAGORDA BAY. RIDGING WILL
MAINTAIN GENERAL SUBSIDENCE THROUGH AT LEAST MID-DAY. KLCH
SOUNDING DISPLAYING QUITE A BIT OF MID-LEVEL DRY AIR (1.42 INCH
PW) THAT WILL LIKELY BE ADVECTED OVER THE AREA WITHIN PERSISTENT
EASTERLY FLOW THROUGH THE DAY. ONCE SURFACE TEMPERATURES ACHIEVE
THE UPPER 80S...WIDELY SCATTERED CONVECTIVE ACTIVITY SHOULD BEGIN
TO BLOSSOM FURTHER INLAND. ALL OF THE SHORT TERM HI-REZ PROGS SHOW
NOTHING OF SIGNIFICANCE...POSSIBLE MORE COVERAGE OVER THE FAR NORTH
BUT...WITHIN THIS AIR MASS THERE IS JUST A MODEST CHANCE THAT 20%
OF THE AREA WILL EXPERIENCE MID-LATE AFTERNOON SHOWERS/ISOLATED
STORMS. 17/12Z MID-UPPER LEVEL ANALYSIS VERIFIES RIDGING AT ALL
MANDATORY LEVELS...RIBBON OF HIGHER MID-LAYER MOISTURE OVER
NORTHEASTERN TEXAS (ALSO SEEN ON GOES SOUNDER PWS) MAY AID IN THE
LATE DAY DEVELOPMENT OF NE`ERN CWA -SHRA/-TSRA ACTIVITY. ALL AND
ALL...A QUIET GO OF THINGS GOING INTO MID-WEEK. 31
PREV DISCUSSION... /ISSUED 645 AM CDT TUE SEP 17 2013/
AVIATION...
WITH A SLIGHTLY DRIER AIR MASS MOVING INTO SOUTHEAST TEXAS TODAY...THINK
THE AREA WILL SEE A LITTLE LESS COVERAGE THAT WHAT WAS AROUND DURING
THE AFTERNOON THROUGH EARLY EVENING HOURS ON MONDAY. CARRIED VCSH 20-23Z
FOR IAH AND HOU AND SGR IN THE 12Z TAFS...BUT LATEST TREND IN THE HIGH
RES MODELS POINTS TOWARD VERY LITTLE AFTERNOON THROUGH EARLY EVENING
COVERAGE. THE MAJORITY OF THE AREA TODAY WILL SEE SCT/BKN CIRRUS WITH
SOME LOW LEVEL CU (FEW/SCT) DEVELOPMENT. LIGHT E/NE WINDS THIS MORNING
EXPECTED TO BECOME E/ESE DURING THE MID/LATE MORNING HOURS THEN SE LATE
IN THE AFTERNOON PEAKING AT AROUND 10 KNOTS. LIGHT AND VARIABLE WINDS
TONIGHT THROUGH SUNRISE WEDNESDAY MORNING. 42
PREV DISCUSSION... /ISSUED 404 AM CDT TUE SEP 17 2013/
DISCUSSION...
THE UPPER LEVEL RIDGE IS CENTERED NEARLY OVERHEAD THIS MORNING
WHILE INGRID HAS NOW DISSIPATED INTO A REMNANT LOW ACROSS THE
HIGHER TERRAIN OF MEXICO. SHOWER ACTIVITY OFFSHORE IS LESS THAN
THE PREVIOUS FEW MORNINGS WITH SOME SCATTERED SHOWERS MOVING
INLAND NEAR MATAGORDA BAY AND AN ISOLATED SHOWER OR TWO TRYING TO
FORM NEAR GALVESTON BAY. TODAY LOOKS TO BE A NEAR REPEAT OF
YESTERDAY WITH HIGHS IN THE LOW TO MID 90S AND A FEW SCATTERED
SHOWERS OR THUNDERSTORMS DEVELOPING ACROSS THE SOUTHERN HALF OF
THE REGION.
A TROPICAL WAVE ACROSS THE WESTERN CARIBBEAN SEA WILL PUSH INTO
THE YUCATAN PENINSULA TODAY AND EMERGE OVER THE BAY OF CAMPECHE ON
WEDNESDAY. MODELS KEEP THIS SYSTEM AS A FAIRLY DISORGANIZED AREA
OF LOW PRESSURE THROUGH THE END OF THE WEEK AND ANY MOVEMENT
TOWARD SOUTHEAST TEXAS WILL BE HAMPERED BY AN APPROACHING COLD
FRONT WHICH WILL REACH THE COAST EARLY SATURDAY MORNING. THIS
FRONT IS ASSOCIATED WITH AN UPPER TROUGH CURRENTLY ACROSS THE
PACIFIC NORTHWEST WHICH WILL BUILD INTO THE CENTRAL PLAINS BY THE
END OF THE WEEK. MOISTURE FROM THE REMNANTS OF INGRID AND MANUEL
WILL BE PULLED NORTHWARD INTO TEXAS AHEAD OF THIS SYSTEM AND WILL
ALLOW FOR SHOWERS AND THUNDERSTORMS TO DEVELOP AHEAD OF THE FRONT
ON FRIDAY. HAVE CONTINUED THE TREND OF INCREASING RAIN CHANCES AND
INTRODUCED LIKELY POPS FOR FRIDAY AFTERNOON DUE TO GOOD MODEL
AGREEMENT ON WIDESPREAD COVERAGE. BETTER RAIN CHANCES WILL SHIFT
SOUTHWARD INTO THE COASTAL COUNTIES AND OFFSHORE WATERS ON
SATURDAY AS THE FRONTAL BOUNDARY REACHES THE COAST. THE UPPER
RIDGE WILL REESTABLISH ITSELF ACROSS THE STATE BY EARLY NEXT WEEK
ALLOWING TEMPERATURES TO WARM BACK INTO THE MID 90S. 38
MARINE...
MODERATE EAST WINDS AND ELEVATED SEAS ARE EXPECTED TO PERSIST
THROUGH MID WEEK. A STORM SYSTEM WILL MOVE ACROSS THE SOUTHERN
PLAINS ON FRIDAY...AND THIS SYSTEM WILL DRAG A COLD FRONT ACROSS
THE COASTAL WATERS LATE ON FRIDAY OR EARLY ON SATURDAY. A GOOD
CHANCE OF SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE FRONTAL
BOUNDARY. 42
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 96 75 96 75 93 / 20 10 20 10 40
HOUSTON (IAH) 94 76 94 76 91 / 20 10 20 20 40
GALVESTON (GLS) 90 81 90 81 89 / 20 20 40 20 40
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 5 PM CDT THIS
AFTERNOON FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO
THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM
HIGH ISLAND TO FREEPORT 20 TO 60 NM.
&&
$$
DISCUSSION...31
AVIATION/MARINE...43
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1139 AM CDT TUE SEP 17 2013
.UPDATE...
LOW LEVEL CLOUDS CONFINED TO THE LAKE RAPIDLY EXPANDED INLAND AS THE
SURFACE INVERSION MIXED OUT. THIS IS BEING FED BY SOUTHEAST WINDS
BRINGING LOW LEVEL MOISTURE INTO EASTERN WI. MADISON WILL EVEN SEE
HINTS OF THESE LOW CLOUDS. EXPECTING THESE CLOUDS TO GRADUALLY
SCATTER OUT DURING THE EARLY AFTERNOON.
MEANWHILE...HIGH CLOUDS WILL CONTINUE TO EXPAND EASTWARD AHEAD OF AN
APPROACHING POTENT SHORTWAVE MOVING THROUGH IOWA THIS MORNING. A
PLUME OF HIGH PRECIPITABLE WATER ACCOMPANIES THIS SHORTWAVE TO
PRODUCE SHOWERS. HRRR BRINGS THE SHOWERS CURRENTLY IN NORTHEAST IOWA
INTO WEST CENTRAL WI AND AVOIDS THE MKX FORECAST AREA. WILL ACCOUNT
FOR A SMALLER AREA OF SHOWERS CURRENTLY IN EASTERN IOWA THAT COULD
SWING UP INTO SOUTH CENTRAL WI LATE THIS AFTERNOON BY INCREASING THE
FORECAST CHANCE POPS A LITTLE EARLIER.
&&
.AVIATION/18Z TAFS/...
MVFR CLOUDS CONFINED TO THE LAKE RAPIDLY EXPANDED INLAND AS THE
SURFACE INVERSION MIXED OUT. THIS IS BEING FED BY SOUTHEAST WINDS
BRINGING LOW LEVEL MOISTURE INTO EASTERN WI. MADISON WILL EVEN SEE
HINTS OF THESE LOW CLOUDS. EXPECTING THESE CLOUDS TO GRADUALLY
SCATTER OUT DURING THE EARLY AFTERNOON.
THEN EXPECT A VFR PERIOD WITH SCT-NMRS -SHRA SPREADING INTO SRN WI
FROM LATE AFTN THRU TNGT. SMALL THREAT FOR T OVER S CENTRAL WI
LATER TNGT INTO WEDNESDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 330 AM CDT TUE SEP 17 2013/
TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM
AREAS OF STRATUS WHICH DEVELOPED OVER THE LAKESHORE COUNTIES AROUND
06Z DUE TO LINGERING HIGH DELTA-T AND INCREASED LOW LEVEL
CONVERGENCE HAVE BECOME MORE PATCHY IN LAST SEVERAL HOURS. LOW
LEVEL WINDS WL CONTINUE TO VEER TO THE SSE THROUGH EARLY MORNING.
WITH DELTA-T REMAINING AROUND 10C...PATCHY STRATUS MAY CONTINUE INTO
THE MORNING AS HIGH CLOUDS INCREASE ACROSS THE AREA.
WATER VAPOR IMAGERY AND WIND PROFILERS INDICATING STRONGER MID-LEVEL
SHORT WAVE VCNTY OF KOMA THAN DEPICTED BY SHORT TERM GUIDANCE. HIGH
PRECIPITABLE WATER VALUES ASSOCIATED WITH THIS WAVE. CURRENTLY
AROUND 0.4 INCHES IN SRN WI. PWAT VALUES TRIPLE RAPIDLY TO AROUND
1.5 INCHES OVER NORTHWEST MO AND WRN IA PER GOES SOUNDER. THIS
DEEPER MOISTURE AND SHORT WAVE MOVES OUR WAY TODAY INTO WRN CWA BY
LATE AFTN AND ACROSS SRN WI TNGT.
305 THETA SURFACE AND LOWER CONDENSATION PRESSURE DEFICITS LINE UP
WELL WITH ONGOING -SHRA OVER WRN IA. THESE LOWER VALUES SPREAD INTO
SOUTHWEST WI LATE AFTN AS SHORT WAVE MOVES INTO THE AREA. HENCE
ADDED SOME POPS TO WRN CWA LATER TODAY AND BEEFED UP POPS SLIGHTLY
THIS EVENING AS MOISTURE AND FORCING ASSOCD WITH SHORT WAVE SPREAD
ACROSS THE AREA. BETTER CHANCE FOR NMRS -SHRA AND ISOLD T LATER
TONIGHT AS DEEPER MOISTURE SETTLES INTO SRN WI AND WEAK LOW LEVEL
JET PIVOTS INTO THE AREA.
WITH STRONG UPSTREAM MOISTURE ADVECTION...THINKING PARTLY SUNNY
SKIES AT BEST TODAY...WITH SOME AREAS LIKELY TURNING MOSTLY CLOUDY.
CLOUDS WILL RETARD HIGH TEMPS A FEW DEGREES...ESPECIALLY WITH SE SFC
WINDS.
WEDNESDAY THROUGH FRIDAY...FORECAST CONFIDENCE...MEDIUM
LOOKS LIKE PRETTY DEEP MOISTURE WEDNESDAY...WITH PRECIPITABLE WATER
VALUES UP TO AROUND 1.75 INCHES. DO THINK THERE WILL BE SOME
ACTIVITY WITH DECENT LOW LEVEL FLOW...WEAK WARM ADVECTION...AND SOME
ELEVATED INSTABILITY. SOUNDINGS LOOK SOMEWHAT CAPPED FOR PART OF THE
DAY AND NOT SEEING A REAL GOOD TRIGGER...SO WENT WITH CHANCE
POPS...NOT DEVIATING MUCH FROM THE PREVIOUS FORECAST. A LOT OF
CLOUDS EXPECTED WEDNESDAY...WITH MODELS STRUGGLING TO MIX TO EVEN
925 MB. THUS KEPT TEMPS A BIT CLOSER TO 2 METER MODEL
VALUES...THOUGH HIGHS WILL STILL BE NEAR TO A COUPLE DEGREES ABOVE
NORMAL.
STRONGEST LOW LEVEL WINDS WILL BE TO THE SOUTHWEST WEDNESDAY
NIGHT...BUT 30-40 KNOT JET DOES POINT INTO THE FORECAST AREA. STILL
WILL BE A GOOD AMOUNT OF MOISTURE WITH INCREASING ELEVATED
INSTABILITY...GETTING AS HIGH AS 1500 J/KG ON NAM SOUNDINGS. WOULD
NOT TAKE MUCH TO KICK OFF MORE SHOWERS/STORMS...SO KEPT CHANCE POPS
GOING.
INSTABILITY IS EXPECTED TO INCREASE EVEN MORE THURSDAY AS A WARM AND
MOIST AIRMASS IS PULLED INTO THE AREA AHEAD OF AN APPROACHING COLD
FRONT. PRECIP CHANCES ARE EXPECTED TO INCREASE AS THE FRONT DRAWS
NEAR...SO WENT WITH LIKELY POPS MAINLY WEST OF MADISON DURING THE
DAY AND THEN ACROSS THE FORECAST AREA IN THE EVENING/OVERNIGHT AS
THE FRONT DRAWS CLOSER OR MOVES THROUGH. LOOKS LIKE A BETTER CHANCE
FOR SOME SUNSHINE AND DEEPER MIXING THAN ON WEDNESDAY. THE AIRMASS
ALOFT WILL BE MILDER AS WELL...SO EXPECTING A WARM DAY INTO THE LOW
80S MOST PLACES.
BUMPED POPS UP A BIT FRIDAY...AS MAIN SHORTWAVE WILL BE MOVING
THROUGH. MODELS HAVE THE SURFACE FRONT RANGING FROM JUST MOVING
INTO THE FORECAST AREA TO JUST THROUGH BY DAYBREAK. STILL A GOOD
AMOUNT OF MOISTURE AND WARM AIR ALOFT AHEAD OF THE SHORTWAVE
THOUGH...SO LOOKS LIKE A DECENT CHANCE FOR LINGERING SHOWERS/STORMS
DURING THE MORNING...MAYBE EVEN HANGING ON IN THE EAST INTO THE
AFTERNOON PER THE SLOWER MODEL SOLUTIONS. COOLER TEMPS ARE LIKELY
FRIDAY...THOUGH HIGHS ARE STILL EXPECTED TO BE NEAR NORMAL VALUES.
SATURDAY THROUGH MONDAY...FORECAST CONFIDENCE...MEDIUM
AFTER A VERY ACTIVE PERIOD...HIGH PRESSURE IS EXPECTED TO SETTLE IN
FOR THE WEEKEND...HANGING ON INTO EARLY NEXT WEEK. SHOULD THUS SEE A
GOOD AMOUNT OF SUNSHINE SATURDAY THROUGH MONDAY WITH SLOWLY WARMING
TEMPERATURES. MAIN ISSUE IS HOW QUICKLY TO WARM THINGS BACK UP...AS
THE GFS KEEPS TEMPS QUITE A BIT COOLER THAN THE ECMWF AND CANADIAN.
GENERALLY SPLIT THE DIFFERENCE IN TEMPS FOR NOW. EITHER WAY...LOOKS
LIKE A PLEASANT STRETCH OF WEATHER.
AVIATION/12Z TAFS/...AREAS OF STRATUS WHICH DEVELOPED OVER THE
LAKESHORE COUNTIES AROUND 05-06Z DUE TO HIGHER DELTA-T AND INCREASED
LOW LEVEL CONVERGENCE HAVE BECOME MORE PATCHY IN LAST HOUR OR SO.
WOULD THINK THIS WILL CONTINUE AS LOW LEVEL WINDS CONTINUE TO VEER
TO THE SSE EARLY THIS MRNG. HOWEVER DELTA-T REMAINS AROUND 10C
THROUGH THE EARLY MORNING SO THREAT FOR LOW CLOUDS WL CONTINUE
THROUGH 15Z OR SO. OTRW EXPECT A VFR PERIOD WITH SCT-NMRS -SHRA
SPREADING INTO SRN WI FROM LATE AFTN THRU TNGT. SMALL THREAT FOR T
OVER S CENTRAL WI LATER TNGT.
MARINE...PRESSURE GRADIENT TIGHTENS OVER LAKE MICHIGAN TODAY AS
HIGH PRESSURE MOVES OFF TO THE EAST AND LOW PRESSURE DEVELOPS IN THE
HIGH PLAINS. WIND SPEEDS WILL INCREASE TO 10 TO 20 KNOTS TODAY AND
PERSIST UNTIL COLD FRONT MOVES THROUGH FRIDAY MORNING. FEW GUSTS MAY
REACH SMALL CRAFT ADVISORY LEVELS DURING THIS TIME BUT NO PROLONGED
PERIOD OF HIGHER GUSTS EXPECTED. WAVES WILL INCREASE TO 2 TO 4 FEET
FOR MUCH OF THE PERIOD AS WELL.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...MBK
WEDNESDAY THROUGH MONDAY...DDV