Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/20/12
AREA FORECAST DISCUSSION
NWS TUCSON AZ
250 PM MST SAT AUG 18 2012
.SYNOPSIS...EXPECT SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS THIS WEEK. DAYTIME TEMPERATURES WILL AVERAGE A
FEW DEGREES BELOW NORMAL.
&&
.DISCUSSION...SCATTERED SHOWERS AND THUNDERSTORMS ONGOING IN AN ARC
FROM SELLS-NOGALES-CHIRICAHUA NATIONAL MONUMENT. OTHER SHOWERS AND
THUNDERSTORMS WERE MOVING SWWD ACROSS NRN GREENLEE COUNTY. 18/12Z
UNIV OF AZ GFS-WRF AND 18/18Z RUC HRRR DEPICTED SIMILAR SOLUTIONS
INTO THIS EVENING. IN SUMMARY...SHOWERS/TSTMS EXPECTED TO REMAIN
SOUTH OF THE TUCSON METRO AREA AND SUBSEQUENTLY DIMINISH THIS
EVENING. ALSO...SHOWERS/TSTMS PROGGED TO MOVE SWWD ACROSS PORTIONS
OF GRAHAM COUNTY AND THEN DIMINISH THIS EVENING.
THE OFFICIAL FORECAST DEPICTS A CHANCE OF SHOWERS/TSTMS MOST
SECTIONS THIS EVENING FOLLOWED BY A SLIGHT CHANCE OF SHOWERS/TSTMS
MOST SECTIONS LATE TONIGHT. BASED ON THE AFOREMENTIONED MESOSCALE
SOLUTIONS...WOULD NOT BE SURPRISED TO SEE POPS FOR TONIGHT REDUCED
SIGNIFICANTLY BY THE EVENING SHIFT.
591 DM HIGH PRESSURE PROGGED TO BE CENTERED OVER NRN AZ SUN. UPPER
HIGH TO REMAIN QUASI-STATIONARY MON-TUE...THEN 18/12Z ECMWF DEPICTS
UPPER RIDGE TO BE FLATTENED LATER IN THE WEEK AS SHORTWAVE TROUGH
MOVES EWD ACROSS THE GREAT BASIN. THERE WILL BE ENOUGH MOISTURE TO
MAINTAIN A CHANCE OF MAINLY AFTERNOON AND EVENING SHOWERS/TSTMS
ACROSS MUCH OF THE AREA THROUGH THURSDAY.
THEREAFTER...18/12Z GFS/ECMWF WERE SIMILAR WITH DEPICTING A DRYING
TREND FRI-SAT. HAVE MADE ONLY VERY MINOR CHANGES TO THE INHERITED
GRIDDED DATA POPS FOR FRI-SAT. THE UPSHOT...A CHANCE OF
AFTERNOON/EVENING SHOWERS/TSTMS EAST AND SOUTH OF TUCSON BY
SAT...AND A SLIGHT CHANCE OF AFTERNOON AND EVENING SHOWERS/TSTMS
ACROSS PIMA/SOUTH CENTRAL PINAL COUNTIES.
HIGH TEMPS SUN-SAT TO AVERAGE A COUPLE OF DEGS OR SO BELOW NORMAL.
&&
.AVIATION...SCT TSRA/SHRA THIS EVENING THEN A SLIGHT CHANCE OF
-TSRA/-SHRA LATE TONIGHT. BRIEF WIND GUSTS MAY APPROACH 40 KTS WITH
THE STRONGEST TSRA THRU EARLY THIS EVENING. SCT TSRA/SHRA MAINLY
EAST OF KTUS SUNDAY AFTERNOON. OTHERWISE...VFR CONDITIONS AND
SURFACE WIND LESS THAN 10 KTS THRU SUNDAY AFTERNOON OR 20/00Z.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...EXPECT SCATTERED MAINLY AFTERNOON AND EVENING
THUNDERSTORMS THIS WEEK.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TUCSON AZ
925 PM MST FRI AUG 17 2012
.SYNOPSIS...EXPECT SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS INTO NEXT WEEK. BELOW NORMAL DAYTIME TEMPERATURES
WILL OCCUR THIS WEEKEND FOLLOWED BY A SLIGHT WARMING TREND NEXT WEEK.
&&
.DISCUSSION...MOSTLY CLOUDY SKIES ACROSS SE AZ AT THIS TIME.
SCATTERED SHOWERS/TSTMS HAVE DEVELOPED DURING THE PAST 30 MINUTES OR
SO WELL TO THE NORTH OF THE WHITE MOUNTAINS. RUC HRRR DEPICTS
SHOWERS/TSTMS TO MOVE INTO NERN SECTIONS DURING THE NEXT 2-3 HOURS.
OTHER LIGHT SHOWERS ARE PROGGED TO DEVELOP NEAR THE INTERNATIONAL
BORDER ADJACENT PIMA COUNTY LATER TONIGHT. GIVEN THE MOIST
AIRMASS...WILL MAINTAIN A SLIGHT CHANCE OF SHOWERS/TSTMS MOST
SECTIONS THE REST OF TONIGHT. SCATTERED SHOWERS/TSTMS ON TAP SAT AS
DIFFLUENT FLOW ALOFT PREVAILS OVER THE AREA.
&&
.PREV DISCUSSION...THE NAM AND GFS DIFFER SLIGHTLY FOR SATURDAY WITH
THE NAM DRYING OUT FASTER THAN THE GFS. SINCE THIS MUCH MOISTURE
CANNOT LEAVE QUICKLY...KEEP LIKELY POPS AT MANY LOCATIONS THROUGH
SATURDAY...THEN TAPER ACTIVITY DOWN SATURDAY NIGHT AND SUNDAY.
NEXT WEEK HAS A WARMING TREND AS THE AIR MASS DRIES OUT. HOWEVER
SCATTER SHOWERS AND THUNDERSTORMS ARE EXPECTED EVERYDAY NEXT WEEK.
THE MODELS KEEP A HEALTHY MONSOON PATTERN OVER THE SOUTHWEST THROUGH
THE FORECAST PERIOD.
&&
.AVIATION...THE NEARLY SATURATED SFC AT KOLS COMBINED WITH THE
RESIDUAL LOW LVL MOISTURE AND LIGHT WINDS MAY CONTRIBUTE TO SOME BR
DEVELOPMENT NEAR THE TERMINAL. WILL HAVE TO REEVALUATE WITH 06Z
ISSUANCE. ALSO...TS DEVELOPMENT EXPECTED ACROSS SRN AZ THURS
AFTN...SPREADING GENERALLY NEWD FROM THE GULF OF CALI.
THEREFORE...HAVE ADDED VCTS MENTION TO BOTH KTUS AND KOLS AFTER
18/17Z RESPECTIVELY. AS FOR NEAR KDUG...TS DEVELOPMENT IS EXPECTED
TO LAG BY A FEW HOURS. OTHERWISE...GENERALLY LIGHT WINDS EXPECTED
THRU THE PERIOD OR 06Z SUN. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.
&&
.FIRE WEATHER...SHOWERS AND THUNDERSTORMS WILL ONCE AGAIN BE
POSSIBLE SATURDAY...WITH A SLIGHT DRYING TREND AFTERWARD.
STILL...WITH FRIDAY/S WETTING RAINFALL GOOD RH RECOVERIES CAN BE
EXPECTED TO CONTINUE. THIS SHOULD CONTRIBUTE TO TEMPERATURES
REMAINING BELOW SEASONABLE NORMALS.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1101 AM MDT SAT AUG 18 2012
.UPDATE...
UPDATED FORECAST TO REMOVE THUNDERSTORMS ACROSS NORTHERN PORTIONS
OF THE SOUTHEAST PLAINS FOR THE REMAINDER OF THE MORNING. HIGH
RES SHORT TERM MODELS HAVE BEEN TRENDING THE FRONT SOUTHWARD WITH
DRIER LOW LEVEL AIRMASS MOVING INTO SE CO THROUGH THE AFTERNOON. HRRR HAS
DEW POINTS DROPPING BACK INTO THE LOWER TO MID 40S ACROSS SOUTHERN
PORTIONS OF THE SOUTHEAST PLAINS...WITH 30S ACROSS THE NRN I-25
CORRIDOR BY 21Z. RUC AND NAM12 A LITTLE MORE OPTIMISTIC KEEPING
SOME LOWER 50 DEW POINTS IN ACROSS BACA COUNTY THROUGH
21Z...BEFORE DROPPING THEM INTO THE 40S TOWARDS 00Z. DEW POINTS
ALREADY A LITTLE DRIER AT KSPD THAN NAM12...AND RAP HAD
PREDICTED. THUS APPEARS BEST CHANCE FOR THUNDERSTORMS WILL BE
ALONG THE EASTERLY UPSLOPE REGIONS OF THE SE MTS...MAINLY WETS AND
SANGRES...AS WELL AS ALONG THE FRONT ACROSS NE NM/TX PANHANDLES
WHERE SFC CONVERGENCE WILL BE MAXIMIZED. IF AN ISOLATED STORM CAN
GET GOING DUE TO ELEVATED HEATING ALONG THE RATON RIDGE/SRN CO
BORDER AREA...IT COULD BRIEFLY STRENGTHEN AS IT MOVES SOUTHWARD
INTO NM/OK PANHANDLE...AS DEEP LAYER SHEARS WILL BE RUNNING AROUND
40 KTS. ALL DEPENDS ON THE AMOUNT OF LOW LEVEL MOISTURE AND TIMING
OF THE DRIER AIR MOVING IN. WILL MAINTAIN SOME ISOLATED POPS ALONG
THE BORDER FOR NOW...WITH POTENTIAL FOR A STRONG STORM OR TWO
(JUST BELOW SEVERE LIMITS) IN THE HAZARDOUS WEATHER OUTLOOK. -KT
&&
.AVIATION...
GUSTY NORTH 15-25 KTS AT KCOS WILL GRADUALLY DECREASE AND SWING
AROUND FROM THE EAST AROUND 10-15 KTS IN THE LATE AFTERNOON. KPUB
WILL SEE LIGHTER WINDS...THOUGH THESE SHOULD INCREASE FROM THE
EAST AT AROUND 10-15 KTS DURING AFTERNOON. ISOLATED TO SCATTERED
AFTERNOON THUNDERSTORMS WILL DEVELOP ACROSS THE MOUNTAINS. THESE
SHOULD DIMINISH AS THEY DRIFT OFF INTO THE MORE STABLE COOLER AIR
ACROSS THE SOUTHEAST PLAINS...AND SHOULD NOT AFFECT THE KCOS OR
KPUB TAF SITE. KALS MAY HAVE THE BEST POTENTIAL OF SEEING A STRAY
VCTS...THOUGH COVERAGE MAY TO TOO LIMITED TO WARRANT INCLUSION IN
THE TAF AS AIRMASS OVER THE REGION WILL BE DRIER THAN YESTERDAY.
THUNDERSTORMS WILL DIMINISH AFTER SUNSET WITH LIGHT DIURNALLY
DRIVEN WINDS UNDER 10 KTS. -KT
&&
.PREV DISCUSSION... /ISSUED 338 AM MDT SAT AUG 18 2012/
SHORT TERM...
(TODAY AND TONIGHT)
CURRENTLY...
A LINE OF SHOWERS/TSRA WERE NOTED EXTENDING NW-SE OVER NE CO. THIS
BAND OF PRECIP WAS MOVING SE. OTHER VERY LIGHT SHOWERS WERE NOTED
OVER EC CO. SOME LIGHT SHOWERS WERE ALSO NOTED OVER SW CO. AN AREA
OF LOW PRESSURE WAS IN THE FT MORGAN AREA AND IT WAS PROGRESSING
SWD. THIS ACTIVITY WAS ASSOCIATED WITH A SHORTWAVE IN THE NW FLOW
ALOFT WHICH WAS MOVING SE.
TODAY AND TONIGHT...
SHOWER ACTIVITY WILL CONTINUE TO MOVE/DEVELOP SE THROUGH THE MORNING
HOURS. SOME OF THIS SHOWER/TSRA ACTIVITY WILL AFFECT THE NE SECTIONS OF
THE CWA...MAINLY KIOWA COUNTY. THE BEST CHANCE OF SHOWERS ACROSS
THIS REGION WILL BE BETWEEN 5 AM AND 11 AM THIS MORNING. AFTER THE
DISTURBANCE MOVES THROUGH THE THREAT OF PRECIP OVER THE FAR E PLAINS
IS EXPECTED TO BE NEAR ZERO AS COOLER MORE STABLE AIR MOVES INTO THE
EASTERN PLAINS.
SHOWER ACTIVITY WILL ONCE AGAIN REDEVELOP OVER THE EAST FACING
SLOPES OF THE EASTERN MOUNTAINS...ESPECIALLY THE S SANGRE MTNS BY
EARLY AFTERNOON. FARTHER NORTH...SHOWERS WILL BE POSSIBLE BUT WILL
BE MUCH MORE ISOLATED. FOR THE PIKES PEAK AREA...ISOLATED
SHOWERS/TSRA WILL BE POSSIBLE...BUT WILL LIKELY FORM AFTER 2 PM.
THE SAN JUANS WILL ALSO SEE A GOOD CHANCE OF SHOWERS/TSRA BY THIS
AFTERNOON. OVER THE REST OF THE INTERIOR MTNS THE PRECIP WILL BE
MORE ISOLATED.
TEMPS WILL BE QUITE NICE WITH TEMPS A COUPLE OF DEGREES BELOW NORMAL
THIS AFTERNOON.
AS FOR THE PLAINS...IT WILL BE DRY. THE ONLY EXCEPTION MAY BE DOWN
ALONG THE CO/NM/OK BORDER WHERE AN ISOLD TSRA MAY DEVELOP DURING THE
AFTERNOON. GIVEN THE NW FLOW ALOFT...THIS ACTIVITY WILL QUICKLY MOVE
SOUTH OUT OF THE STATE. IT WILL BE BREEZY OVER THE PLAINS TODAY AS
THE FRONT MOVES S ACROSS THE REGION THIS MORNING. BY THIS AFTERNOON
NE WINDS OF 10-20 MPH WILL BE COMMON.
FOR THIS EVENING...ANY PRECIP...IF OCCURRING...WILL LIKELY BE ALONG
THE CO/NM BORDER OR SAN JUANS...AND WILL QUICKLY DISSIPATE. TEMPS
TONITE WILL MAINLY BE IN THE 50S PLAINS...WITH 30S AND 40S
MTNS/VALLEYS. /34
LONG TERM...
(SUNDAY THROUGH NEXT SATURDAY)
MAIN FORECAST CONCERNS CONTINUE TO CENTER ON IMPACT OF FRONTAL
SYSTEMS THAT WILL AFFECT THE AREA FIRST ON MONDAY AND AGAIN LATE
WED OR THU. OVERALL PICTURE CONTINUES TO LOOK PRETTY TYPICAL FOR
LATE AUGUST.
SUN-MON SHOULD BE THE COOLEST DAYS OF THE PERIOD IN THE WAKE OF A
FRONTAL PASSAGE THIS WEEKEND. EXPECT TEMPS IN THE LOWER TO MID 80S
FOR THE PLAINS BOTH DAYS. SUNDAY CONTINUES TO LOOK MOSTLY DRY...WITH
MOST OF THE PRECIP CONFINED TO THE SRN MTS IN THE AFTERNOON-EVE. GFS
STILL IS OVERDONE WITH QPF...BUT IN FOLLOWING THE NAM SOLUTION HAVE
BUMPED UP POPS SLIGHTLY FOR THE NRN MT RANGES...INCLUDING PIKES
PEAK...FOR THE LATE AFTERNOON.
NEXT FRONT ARRIVES EARLY ON MON...AND WILL RESULT IN MORE
WIDESPREAD SHOWERS OVR THE CWA. AFTER A BIT OF A LULL IN THE
PRECIP MID DAY...COULD SEE AN INCREASE IN SHWR ACTIVITY AGAIN IN
THE LATE AFTERNOON THRU EARLY EVE AS UPSLOPE WINDS COMBINE WITH
SOME MODEST INCREASE IN INSTABILITY. SEVERAL CONVECTIVE COMPLEXES
ARE POSSIBLE BY LATE MON EVE...BUT SHOULD BE MOSTLY E OF OUR AREA
BY THAT TIME. WILL HANG ON TO SOME LOW POPS NR THE KS/OK BORDERS
THRU MON NIGHT.
TUE THRU WED THE RIDGE REBUILDS OVR THE ROCKIES AND TEMPS WILL
REBOUND OVR THE PLAINS TO THE UPPER 80S AND POSSIBLY LOWER 90S.
MOISTURE WILL LARGELY BE CONFINED TO THE SRN MTS...SAN JUANS AND
SPANISH PEAKS REGION. COULD SEE SOME SPOTTY HEAVY AMTS OF PRECIP
OVR THE SAN JUANS THRU THIS PERIOD. NEXT...MORE SIGNIFICANT...FRONT
ARRIVES LATE WED OR EARLY THU...AND THIS SHOULD BRING A GOOD CHANCE
OF SHOWERS TO ALL OF SE CO. THE UPPER RIDGE LOOKS TO REBUILD LATE
IN THE WEEK FOR MORE DRY AND WARM WX. 44
AVIATION...
VFR EXPECTED AT KCOS AND KPUB NEXT 24. KALS MAY SEE AND ISOLD TSRA
LATE THIS AFTERNOON...OTHERWISE VFR. A COOL FRONT WILL MOVE ACROSS
KCOS AOA 15-16Z WITH SOME GUSTY N WINDS AFTER FROPA. THE FRONT WILL
COME ACROSS KPUB ABOUT AN HOUR LATER. WINDS ON THE PLAINS WILL SHIFT
TO THE NORTHEAST THIS AFTERNOON.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31/23
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1055 PM EDT SUN AUG 19 2012
.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN TONIGHT. A WEAK AREA OF LOW PRESSURE
MOVING NORTHEAST TOWARD THE MID ATLANTIC COAST LATE TONIGHT WILL
PASS SOUTHEAST OF THE AREA MONDAY INTO MONDAY NIGHT. HIGH
PRESSURE BUILDS BEHIND THE DEPARTING LOW...WITH ANOTHER WEAK
COASTAL LOW POSSIBLE WEDNESDAY INTO THURSDAY. HIGH PRESSURE
RETURNS FOR THE END OF THE WEEK INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
FORECAST ON TRACK WITH DRY WEATHER THIS EVENING. THE ONLY CHANGES
WERE MADE TO POP GRIDS FOR LATE TONIGHT TO SHOW SOME POTENTIAL FOR
ISOLATED SHOWERS. THIS IS IN RESPONSE TO SOME PVA ALOFT AT 500 MB
AS WELL AS INCREASING SOUTHWESTERLY JET AT AROUND 250MB PROMOTING
GREATER DIVERGENCE. THIS IS TURN WILL HELP A LOW DEVELOP OFF THE
MID-ATLANTIC COAST. LAST 3 RUNS OF THE HRRR FORECAST REFLECTIVITY HAVE
SHOWN DEVELOPMENT OF SHOWERS STARTING BETWEEN 7-10Z MONDAY AND NEW
SREF ALSO SHOWS A LOW CHANCE NEAR THIS TIMEFRAME.
HIGH PRESSURE OVER THE REGION WILL WEAKEN TONIGHT. THIS WILL ALLOW
AN AREA OF LOW PRESSURE TO MOVE OFF THE MID-ATLANTIC COAST BY MONDAY
MORNING. CLOUDS THICKEN AND LOWER OVERNIGHT AND MUCH OF THE
OVERNIGHT PERIOD WILL REMAIN DRY...HOWEVER SOME LIGHT SHOWERS ARE
EXPECTED TO DEVELOP TOWARDS DAYBREAK. OVERNIGHT LOWS TONIGHT ARE
EXPECTED TO FALL INTO 50S AND 60S.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
LOW PRESSURE WILL PASS SOUTHEAST OF THE REGION THROUGH THE SHORT
TERM. MODELS STILL STRUGGLING WITH HOW MUCH PRECIPITATION THE CWA
WILL RECEIVE WITH THIS SYSTEM. 12Z NAM HAS THE REGION RECEIVING
BETWEEN 0.1 TO 0.30 OF PRECIP...WITH THE HIGHER AMOUNTS ACROSS THE
NYC METRO AND LONG ISLAND AND LESSER AMOUNTS NORTH AND WEST. THE 12Z
GFS KEEPS THE REGION DRY COMPLETELY. THEREFORE...HAVE LOWER POPS A
BIT AND WILL CARRY SCATTERED SHOWERS THROUGH THE DAY MONDAY. BY
MONDAY NIGHT...AS THE LOW MOVES EAST POPS WILL GRADUALLY LOWER AND
TAPER OFF BY MIDNIGHT. EXPECT MOSTLY CLOUDY TO CLOUDY SKIES FOR MUCH
OF THE PERIOD. THIS WILL KEEP TEMPERATURES COOL. CONTINUES WITH THE
FORECAST TREND OF FOLLOWING THE MET GUIDANCE AS HIGHS WILL ONLY
REACH THE LOWER AND MIDDLE 70S. MAV GUIDANCE WAS A GOOD 6-9 DEGREES
WARMER SEEMED UNREALISTIC WITH CLOUD COVER AND RAIN WAS NOT USED.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
WHILE THE MODELS ARE COMING INTO BETTER AGREEMENT FOR THE LONG
TERM...THERE ARE SOME MINOR DISCREPANCIES THAT LEAD TO SOME
UNCERTAINTY...ESPECIALLY MID WEEK. SURFACE HIGH PRESSURE BEGINS TO
BUILD IN TUESDAY AS THE SURFACE LOW DEPARTS TO THE NORTHEAST. A WEAK
TROUGH JUST TO THE NORTH...COMBINED WITH A WEAK SHORTWAVE MOVING
THROUGH ALONG THE EASTERN SIDE OF THE DEEPENING UPPER LEVEL TROUGH
COULD PRODUCE JUST ENOUGH LIFT TO GENERATE SOME AFTERNOON SHOWERS.
INSTABILITY REMAINS ON THE LOWER END...SO NOT EXPECTING MUCH IN THE
FORMATION OF THUNDERSTORMS...THOUGH AN ISO TSTORM CAN NOT BE RULED
OUT. THE HIGH BEGINS TO TAKE MORE CONTROL OF THE REGION BY TUES
NIGHT...SO HAVE DIMINISHED POPS FOR OVERNIGHT.
NOW...SOME UNCERTAINTY WED INTO THURS WITH A DEVELOPING SURFACE LOW
OFF THE MID ATLANTIC COAST. MODELS ARE BEGINNING TO COME MORE INTO
LINE WITH THIS LOW DEVELOPING TUES NIGHT AND PASS TO THE SOUTH AND
EAST OF THE CWA. THIS PATH WOULD LEND TO THE IDEA OF THE PRECIP
STAYING MORE TO THE SOUTH...HOWEVER...THE UPPER LEVEL TROUGH BEGINS
TO MOVE THE NORTHEAST...WHICH MAY AID IN SOME DEVELOPING PRECIP WED.
OVERALL THOUGH...CONFIDENCE NOT GREAT AT THIS TIME THAT ANYTHING
WILL DEVELOP...ESP OVER THE NORTHERN FRINGES OF THE CWA...SO WILL GO
WITH SLIGHT CHC POPS. IF THE LOW EDGES MORE TO THE NORTH...THEN WE
COULD SEE MORE SCT ACTIVITY DURING THE DAY WED. WITH THE EASTERLY TO
NORTHEASTERLY FLOW...ONCE AGAIN ANY PRECIP LOOKS TO BE MORE JUST
RAIN SHOWERS...WITH AN ISO THREAT OF THUNDER.
END OF THE WEEK...HIGH PRESSURE HIGH PRESSURE TAKES OVER AT THE
SURFACE. A MORE ZONAL FLOW DEVELOPS ALOFT...WITH MULTIPLE
DISTURBANCES POSSIBLE FOR THE WEEKEND WHICH COULD BRING MORE PRECIP
IN.
NEAR NORMAL TEMPERATURES EXPECTED FOR THE COMING WEEK...WITH GRADUAL
WARMING BY THE END OF THE WEEK WITH THE RETURN FLOW USHERING IN
WARMER AND MORE MOIST AIR.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE SLIDES TO THE EAST INTO TONIGHT. WEAK LOW PRESSURE
MOVES WELL SOUTH OF LONG ISLAND ON MONDAY.
VFR EXPECTED THROUGH MUCH OF TONIGHT WITH WINDS LESS THAN 10 KT.
LIGHT AND VARIABLE WINDS WILL TURN MORE EASTERLY ON MONDAY IN
RESPONSE TO LOW PRESSURE MOVING SOUTH OF LONG ISLAND. THERE IS
UNCERTAINTY HERE AND CONFIDENCE IS LOW WITH WIND DIRECTIONS AFTER
12Z MON. WIND DIRECTIONS COULD BE MORE EASTERLY OR SOUTHERLY THAN
FORECAST.
SHOWERS WILL BE POSSIBLE MAINLY ON MONDAY ACROSS THE REGION. WITH
SHOWERS EXPECTED TO BE LIGHT AND THE UNCERTAINTY IN TIMING AND
PLACEMENT OF THESE SHOWERS...VCSH WAS USED IN TAF. VFR IS
FORECAST...ALTHOUGH MVFR WILL BE POSSIBLE AT TIMES.
OUTLOOK FOR 00Z TUESDAY THROUGH FRIDAY...
.MON NIGHT...MVFR OR LOWER CONDS IN ANY SHOWERS REMAINING BUT
EXPECTED TO DIMINISH WITHIN THE EVENING.
.TUE-FRI...MAINLY VFR.
&&
.MARINE...
HIGH PRESSURE OVER THE AREA WATERS WEAKENS TONIGHT. A WEAK AREA
OF LOW PRESSURE WILL PASS SOUTHEAST OF THE WATERS DURING THE DAY
MONDAY AND INTO MONDAY NIGHT. THIS WILL ALLOW SEAS TO
INCREASE...BUT WILL REMAIN BELOW SMALL CRAFT LEVELS. SEAS ARE
EXPECTED TO BUILD TO 3 TO 4 FT.
MAINLY SUB-SCA CONDITIONS EXPECTED FOR THE WEEK INTO THE COMING
WEEKEND WITH A WEAK PRESSURE GRADIENT REMAINING OVER THE REGION. THE
ONE THING TO WATCH IS THE TRACK OF THE POTENTIAL COASTAL LOW MID
WEEK...WHICH COULD PRODUCE GUSTS UP TO 25 KTS IF IT MOVES FARTHER TO
THE NORTH.
&&
.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH THE WEEK.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BC/SEARS
NEAR TERM...BC/JM
SHORT TERM...BC
LONG TERM...SEARS
AVIATION...JM
MARINE...BC/SEARS
HYDROLOGY...BC/SEARS
AREA FORECAST DISCUSSION
NWS TAUNTON MA
936 PM EDT SUN AUG 19 2012
.SYNOPSIS...
A FEW SHOWERS MAY GRAZE SOUTHEAST NEW ENGLAND MON AND MON NIGHT AS
LOW PRESSURE PASSES WELL SOUTHEAST OF THE REGION. OTHERWISE...A
RIDGE OF HIGH PRESSURE WILL BRING MAINLY DRY AND SEASONABLE WEATHER
RIGHT THROUGH NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
935 PM UPDATE...
SATELLITE LOOP SHOWS PLENTY OF HIGH CLOUDS STREAMING NE UP EASTERN
SEABOARD TONIGHT. THIS WILL BE CASE OVERNIGHT AS SHORT WAVE LIFTS
OUT OF MID ATLANTIC REGION. RADAR MOSAIC SHOWS SOME SHOWERS WELL
OFF DELMARVA WHICH MODELS SLOWLY ADVANCE TOWARD SOUTHERN NEW
ENGLAND OVERNIGHT. 3KM HRRR SHOWS LEADING EDGE OF THESE SHOWERS
ARRIVING ON ISLANDS AROUND 5 AM WITH BULK OF ACTIVITY REMAINING
OFFSHORE. FORECAST HANDLES THIS SCENARIO WELL SO NOT PLANNING ANY
CHANGES.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
12Z GFS/ECMWF/CMC MODELS ALL ARE FARTHER SOUTHEAST WITH THE LOW
PRESSURE AREA DEVELOPING TO OUR SOUTH...PASSING WELL TO THE SOUTH
OF NANTUCKET LATER MON AFTERNOON. THEY ALL CONFINE MEASURABLE
PRECIPITATION TO A LINE FROM NEAR THE CAPE COD CANAL TO SOUTHERN RI.
ONLY THE 12Z NAM WOULD BRING LIGHT PRECIPITATION AS FAR NORTH AS
THE NH BORDER DURING THE DAY...BUT IT IS NOTED THAT THE NAM
AVIATION CEILING FORECAST IN THOSE AREAS IS 10000 FT...SO IF IT IS
TRUE...AT BEST WOULD ONLY EXPECT A HUNDREDTH OR TWO. MOST
IMPORTANTLY...WATER VAPOR SATELLITE IMAGERY TRENDS HAVE BEEN SHOWING
THE WESTERN EDGE OF CLOUDINESS SLIDING SLOWLY BUT STEADILY
EASTWARD...WHICH WOULD LEND CREDENCE TO THE GFS/ECMWF/CMC SOLUTIONS.
AS A RESULT...HAVE GONE WITH PARTLY TO MOSTLY CLOUDY SKIES IN THE
NW WITH VERY LOW POPS... AND CLOUDY SKIES WITH A LOW CHANCE OF
SHOWERS ELSEWHERE...EXCEPT AND SHOWERS LIKELY ON CAPE COD AND THE
ISLANDS.
THERE IS ALSO A COLD FRONT DROPPING SE FROM UPSTATE NY AND
NORTHERN NEW ENGLAND AND A WEAK VORTICITY MAX APPROACHING WESTERN
MA. THIS MAY TRIGGER WIDELY SCATTERED SHOWERS IN FAR WESTERN AREAS
TOWARD EVENING...BUT BEST CHANCE IS IN NY STATE.
MAVMOSGUID BIAS CORRECTED GRIDS AGAIN USED FOR HIGHS MON...MAINLY
UPPER 70S TO NEAR 80...WARMEST IN THE MERRIMACK AND CONNECTICUT
VALLEYS. HIGHS ONLY MID 70S CAPE COD AND ISLANDS WHERE CLOUDIER WITH
BETTER SHOWER PROBABILITIES.
MONDAY NIGHT...ANY SHOWERS WILL HAVE MOVED WELL OFFSHORE BY EARLY
EVENING. WEAK LOW PRESSURE TROUGH/REMNANTS OF A COLD FRONT MOVES
THROUGH BUT ITS PASSAGE SHOULD BE RELATIVELY BENIGN. PARTLY TO
MOSTLY CLOUDY SKIES AND LOWS MAINLY 55 TO 60.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
HIGHLIGHTS...
* MAINLY DRY AND SEASONABLE INTO NEXT WEEKEND
DETAILS...
TUESDAY THROUGH SUNDAY...
A RIDGE OF HIGH PRESSURE SHOULD RESULT IN MAINLY DRY AND SEASONABLE
WEATHER RIGHT THROUGH NEXT WEEKEND. WE CAN/T COMPLETELY RULE OUT A
DIURNALLY DRIVEN ISOLATED BRIEF SHOWER OR TWO AT TIMES...BUT AREAL
COVERAGE/DURATION WOULD LIKELY BE QUITE LIMITED. WE WILL HAVE TO
WATCH A FEW WAVES OF LOW PRESSURE THAT WILL PROBABLY TRACK SOUTHEAST
OF THE BENCHMARK OVER THIS PERIOD. THIS SHOULD KEEP MOST OF THE
PRECIPITATION TO THE SOUTH OF OUR REGION...ALTHOUGH A FEW SHOWERS
MAY GRAZE OUR REGION WED/WED NIGHT IF ONE LOW PRESSURE GETS CLOSE
ENOUGH BUT THAT IS UNCERTAIN. BEST CHANCE WOULD BE NEAR THE SOUTH
COAST.
HIGHS SHOULD MAINLY BE IN THE UPPER 70S AND LOWER 80S MOST OF THE
PERIOD...WITH SOME LOCATIONS PERHAPS REACHING INTO THE MIDDLE 80S
THU/FRI. RELATIVE HUMIDITY LEVELS WILL REMAIN COMFORTABLE FOR
OUTDOOR ACTIVITIES.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
OVERVIEW...
MODERATE TO HIGH CONFIDENCE IN TAFS. BRIEF MVFR CEILINGS ARE
POSSIBLE ACROSS THE CAPE/ISLANDS THIS EVENING. OTHERWISE...VFR
TONIGHT WITH MID AND HIGH CLOUDS...BUT THERE WILL BE SOME PATCHY FOG
LATE IN THE TYPICALLY PRONE LOCATIONS. VFR CONDITIONS ON
MON...EXCEPT A LOW PROBABILITY OF BRIEF MVFR CONDITIONS SOUTHEAST
NEW ENGLAND COAST IN A FEW SHOWERS. VFR MONDAY NIGHT EXCEPT FOR
PATCHY MVFR AGAIN IN ANY LATE NIGHT FOG...ESPECIALLY NW MA AND SW NH.
KBOS TAF...HIGH CONFIDENCE IN TAF. VFR CONDITIONS TONIGHT AND
MONDAY.
KBDL TAF...HIGH CONFIDENCE IN TAF. VFR CONDITIONS TONIGHT AND
MONDAY.
OUTLOOK...TUESDAY THROUGH FRIDAY...
MODERATE TO HIGH CONFIDENCE. MAINLY VFR CONDITIONS OTHER THAN
PATCHY FOG AT TIMES IN THE PARTICULARLY PRONE LOCATIONS DURING THE
OVERNIGHT/EARLY MORNING HOURS.
&&
.MARINE...
HIGH CONFIDENCE THROUGH MONDAY NIGHT. WINDS AND SEAS BELOW SMALL
CRAFT ADVISORY THRESHOLDS THROUGH THE PERIOD. SEAS WILL BE
BUILDING FROM 1 FT TONIGHT TO CLOSER TO 3 TO 4 FT BY MONDAY NIGHT
OVER THE OUTER WATERS AS LOW PRESSURE TRACKS TO THE SOUTH OF THE
40/70 BENCHMARK.
OUTLOOK...TUESDAY THROUGH FRIDAY...
HIGH CONFIDENCE THAT WINDS AND SEAS SHOULD GENERALLY REMAIN BELOW
SMALL CRAFT ADVISORY CRITERIA THROUGH THE PERIOD WITH A WEAK
PRESSURE GRADIENT IN PLACE.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...FRANK/GAF
NEAR TERM...JWD
SHORT TERM...GAF
LONG TERM...FRANK
AVIATION...FRANK/GAF
MARINE...FRANK/GAF
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
810 PM EDT SUN AUG 19 2012
.UPDATE (REST OF TONIGHT)...
00Z WATER VAPOR AND H4 RAP ANALYSIS CONTINUE TO SHOW AND UPPER LEVEL
PATTERN DOMINATED BY LONGWAVE RIDGING OVER THE WESTERN STATES
FOLLOWED DOWNSTREAM BY A DEEP LATE SUMMER TROUGH OVER THE EAST. THE
TROUGH AXIS EXTENDS FROM THE GREAT LAKES DOWN TOWARD THE
NORTH-CENTRAL GULF OF MEXICO COAST. THIS POSITIONS PLACES THE
NORTHERN HALF OF OUR FORECAST AREA WITHIN A FAVORABLE QUADRANT TO
FEEL THE SYNOPTIC SUPPORT FROM SHORTWAVE IMPULSES PASSING THROUGH
THE TROUGHS BASE.
AT THE SURFACE...FORECAST AREA RESIDES BETWEEN THE SUBTROPICAL RIDGE
AXIS TO OUR SOUTH AND A QUASI-STATIONARY FRONTAL BOUNDARY TO OUR
NORTH. THE GRADIENT BETWEEN THESE 2 FEATURES CONTINUES TO PROVIDE A
MOIST SW FLOW IN THE LOWER LEVELS.
LOW LEVEL FOCUS AHEAD OF THE FRONTAL BOUNDARY HAS COMBINED WITH WEAK
SYNOPTIC SUPPORT ASSOCIATED WITH THE UPPER TROUGH TO SUPPORT
NUMEROUS SHOWERS AND STORMS THIS AFTERNOON/EARLY EVENING OVER THE
NORTHERN WATERS AND NATURE COAST ZONES. COLD POOL MIGRATION HAS BEEN
EVER SO SLOWLY BUILDING THIS BAND OF CONVECTION SOUTHWARD THE PAST
SEVERAL HOURS. CURRENTLY THE 18Z GFS AND LOCAL HIGH RESOLUTION
WRF-ARW GUIDANCE ARE HANDLING THE EVOLVING PATTERN BEST...AND HAVE
MADE UPDATES BASED ON A BLEND OF THESE. RAIN CHANCES WILL REMAIN IN
THE LIKELY/CATEGORICAL RANGE NORTH OF PINELLAS/HILLSBOROUGH THROUGH
THE REMAINDER OF THE EVENING...HOWEVER HAVE RAISED POPS TO LIKELY TO
INCLUDE PINELLAS AND HILLSBOROUGH COUNTIES THROUGH 06Z BASED ON
RADAR PRESENTATION AND GUIDANCE CONSENSUS. TOUGH CALL JUST HOW FAR
SOUTH THE MAIN BAND WILL MIGRATE AS MUCH OF THE AVAILABLE GUIDANCE
DOES SHOW A SIGNIFICANT DISSIPATION OF THE ACTIVITY AFTER MIDNIGHT.
WILL CONTINUE TO MONITOR AND UPDATE THE POPS FURTHER SOUTH IF
NECESSARY.
LATE AT NIGHT WHILE THE INITIAL BAND OF CONVECTION IS HOPEFULLY
FALLING APART...THE NEXT IMPULSE WILL BE APPROACHING FROM THE LOWER
MS VALLEY...AND THIS WILL LIKELY START INCREASING COVERAGE ONCE
AGAIN OVER THE FAR NORTHERN WATERS INTO SPOTS LIKELY DIXIE/CITRUS
COUNTIES. LOOKS LIKE MORE OF THE SAME FOR MONDAY AS FAVORABLE
DYNAMICS FOR LIFT KEEP RAIN CHANCES IN THE LIKELY RANGE OVER THE
NORTHERN HALF OF THE AREA AND IN THE CHANCE RANGE FURTHER SOUTH AWAY
FROM THE INFLUENCE OF THE UPPER TROUGH.
&&
.AVIATION...
ACTIVE AREA OF SHOWERS AND THUNDERSTORMS COULD IMPACT PIE AND TPA
THIS EVENING. WILL NEED TO KEEP VCTS FOR ENTIRE TAF PERIOD AS
CONDITIONS FAVOR ANYTIME SHOWERS AND STORMS. STILL PRIMARILY VFR
WITH FEWER SHRA/TSRA AROUND PGD...FMY AND RSW.
&&
.MARINE...
ATLANTIC HIGH PRESSURE RIDGES ACROSS SOUTH FL WATERS THROUGH TUE AS
A FRONTAL TROUGH SAGS INTO THE NORTH GULF MON AND THEN DISSIPATES.
THE RIDGE AXIS MOVES TO CENTRAL FL WED AND THEN NORTH FL BY FRI.
SOUTH AND SOUTHWEST WINDS PREVAIL...GENERALLY AROUND 10 KT WITH
SEAS 1 TO 2 FT. SHOWERS AND THUNDERSTORMS WILL CONTINUE TO BE THE
MAIN MARINE HAZARD.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 78 90 77 89 / 60 60 30 50
FMY 76 93 77 91 / 20 30 30 40
GIF 75 92 75 92 / 60 60 30 50
SRQ 78 90 76 90 / 50 50 30 50
BKV 73 91 72 90 / 80 60 30 50
SPG 79 89 79 89 / 60 50 30 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...MROCZKA
AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
321 PM EDT SAT AUG 18 2012
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
EXPECT AN ACTIVE WEATHER PATTERN THROUGH THE SHORT TERM. SURFACE
ANALYSIS SHOWS A COLD FRONT NEAR A CARROLLTON TO ATLANTA TO ATHENS
LINE. EXPECT A STRONG UPPER DISTURBANCE OVER MS TO TRAVERSE THE AREA
AND SPARK ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ALONG AND
SOUTH OF THE FRONT THROUGH MID EVENING. THIS ACTIVITY SHOULD
DIMINISH BY MIDNIGHT... BUT THE BREAK MAY BE SHORT LIVED AS A SERIES
OF DISTURBANCES BEGIN TO CARVE A LONG WAVE TROUGH ALONG THE LOWER MS
VALLEY REGION OVERNIGHT AND ON SUNDAY. AS A RESULT... EXPECT A VERY
ACTIVE SW FLOW ALOFT TO INTERACT WITH AN INCREASINGLY MOIST AND
UNSTABLE AIRMASS TO SPARK SCATTERED TO WIDESPREAD CONVECTION ACROSS
MUCH OF THE AREA STARTING EARLY ON SUNDAY AND CONTINUING THROUGH
MONDAY. THE GFS SHOWS A SURFACE LOW DEVELOPING ALONG THE STALLED
FRONT AND SWEEPING ACROSS THE STATE MONDAY NIGHT... WITH THE
TRAILING COLD FRONT FINALLY BRINGING SOME DRIER CONDITIONS TO AT
LEAST NORTH GA BY TUESDAY MORNING. AT THIS TIME...EXPECT THE
STRONGER STORMS TO OCCUR ON MONDAY AS THE UPPER TROUGH DEEPENS AND A
SURFACE LOW PUSHES INTO THE STATE DURING DAYTIME HEATING. ALTHOUGH .
AMPLE CLOUD COVER AND WIDESPREAD SHOWERS SHOULD HELP HINDER SEVERE
STORM DEVELOPMENT ON SUNDAY AND MONDAY... THE INCREASED FORCING
EXPECTED ON MONDAY WARRANTS GREATER CONCERN FOR MONDAY AFTERNOON AND
EVENING. SPC DOES NOT HAVE THE FORECAST AREA OUTLOOKED AT THIS
TIME... BUT WILL MONITOR THIS POTENTIAL CLOSELY GOING INTO MONDAY.
OTHERWISE...LEANED TOWARD A MAV AND MET BLEND FOR LOWS AND HIGHS
THROUGH THE PERIOD WITH SOME UNCERTAINTY ON TIMING AND COVERAGE OF
CONVECTION AT THIS TIME.
39
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
OVERALL GUIDANCE IN BETTER AGREEMENT THAN YESTERDAY WITH MAIN
INFLUENCING FEATURES FOR THE MAJORITY OF THE LONG TERM. THROUGH
TUESDAY BOTH THE GFS AND ECMWF KEEP THE MOISTURE FIELD SOUTH OF THE
NEARLY STATIONARY SFC FRONT ACROSS CENTRAL GEORGIA...WHICH
EVENTUALLY SAGS ACROSS SOUTHERN GEORGIA FOR WEDNESDAY INTO THURSDAY.
CURRENT POPS OF LOW END CHANCE IN THE SOUTH TO SLIGHT NORTHWARD
THROUGH THIS PERIOD SEEM REASONABLE. THE ECMWF HINTS AT A WEAK UPPER
LOW DRAWING MOISTURE IN A BIT FARTHER NORTHWARD THAN THE GFS ON
THURSDAY... BUT THERE IS DECENT UNCERTAINTY IN THIS SOLUTION THIS
FAR OUT SO WILL KEEP BEST CHANCE POPS IN SOUTH AND EAST PORTIONS.
WEAK SFC HIGH BUILDING INTO AREA NEAR END OF THE WEEK SHOULD LIMIT
CONVECTIVE DEVELOPMENT SO WILL ALSO CONTINUE THE CURRENT SLIGHT POPS
FOR THAT TIMEFRAME. NO SIGNIFICANT CHANGES NEEDED TO THE FORECAST
TEMPS AS LATEST MEX GUIDANCE KEEPING BETTER CONSISTENCY BETWEEN RUNS
THAN YESTERDAY. WITH ALL CONSIDERED...FORECAST LOOKS TO BE ON TRACK.
PREVIOUS DISCUSSION FOLLOWS...
03
.PREVIOUS DISCUSSION ISSUED AT 426 AM EDT SAT AUG 18 2012/...
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
CWA REMAINS UNDER THE INFLUENCE OF A LONGWAVE TROUGH AT THE
BEGINNING OF THE LONG TERM. LATEST GUIDANCE STILL BRINGS A WAVE
ACROSS THE CWA NEAR THE BEGINNING OF THE LONG TERM BUT ABOUT 12
HOURS EARLIER THAN SUGGESTED YESTERDAY WITH MODELS SHOWING SUNDAY
NIGHT NOW. ALTHOUGH NAM/GFS/ECMWF/SREF SHOW SOME REFLECTION OF A
SFC LOW ASSOCIATED WITH THIS DISTURBANCE...THE GFS IS BY FAR THE
STRONGEST AND APPEARS TO BE OVERDONE ON STRENGTH AND PRECIP. AT
LEAST THROUGH MONDAY...LEANED TOWARD THE NAM/ECMWF SOLUTION TO
ACCOUNT FOR THE OVERDONE GFS. MAIN IMPACT WAS TO POPS THAT ARE IN
THE SLIGHT CHANCE TO LIKELY CATEGORY THROUGH MONDAY AS OPPOSED TO
THE LIKELY AND CATEGORICAL POPS SUGGESTED BY THE GFS. AFTER THE
INFLUENCES FROM THE WAVE ON MONDAY MOVES OUT OF THE CWA...RAIN
CHANCES DECREASE. BEST MOISTURE REMAINS ACROSS SOUTHERN HALF OF
CWA SO HAVE CONTINUED TO SHOW BEST POPS ACROSS THAT AREA. BY
MIDWEEK...LONGWAVE TROUGH CONTINUES TO BREAK DOWN ACROSS THE AREA
AND BEST MOISTURE CONTINUES TO SHIFT OFF TO THE EAST AS HIGH
PRESSURE PUSHES INTO THE CWA AT THE SFC. THIS WILL HELP TO LIMIT
POPS TO SLIGHT CHANCE ACROSS THE NORTH AND CHANCE ACROSS THE
SOUTHERN HALF OF THE CWA.
MEX MAX TEMPS ARE SLIGHTLY HIGHER THAN PREVIOUS RUN. LIKE THIS TREND
AND HAVE EVEN NUDGED MAX TEMPS UP A DEGREE IN SOME PLACES. MIN TEMPS
APPEAR A LITTLE COOL DURING THE WORK WEEK...SO HAD TO MAKE SOME
ADJUSTMENTS UPWARD HERE TOO.
11
&&
.AVIATION...
18Z UPDATE...
VFR CONDITIONS CURRENTLY OVER ALL TAF SITES AND EXPECTED TO PREVAIL
THROUGH THE TAF PERIOD. A COLD FRONT REMAINS NEARLY STATIONARY
ACROSS THE ATLANTA METRO AREA... AND WITH AN ACTIVE WESTERLY FLOW
ALOFT...EXPECT ANOTHER ROUND OF SCATTERED CONVECTION BY LATE
AFTERNOON-EARLY EVENING. LATEST HRRR MODEL INDICATES CONVECTION WILL
FIRE NEAR THE FRONT AND BRUSH THE ATLANTA AREA TAF SITES BY
21-23Z...BUT KEEPS THE MAIN CONVECTION JUST SOUTH OF ATL. WILL PLAY
IT SAFE AND CONTINUE TO SHOW TEMPO -TSRA 21-24Z FOR ALL TAF SITES
TODAY. MODELS AGREE ON WIDESPREAD CONVECTION MOVING IN LATE TONIGHT
AND PREVAILING ON SUNDAY. WILL SHOW VCSH BY 09Z...AND PREVAILING
-SHRA BY 12Z WITH PROB30 -TSRA 12-19Z SUN FOR NOW. WINDS WILL REMAIN
MAINLY WESTERLY AT 8KTS OR LESS.
//ATL CONFIDENCE...
18Z UPDATE...
MODERATE CONFIDENCE ON CONVECTION AND TIMING. HIGH CONFIDENCE ON
ALL OTHER ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 68 86 68 84 / 30 50 60 60
ATLANTA 69 86 69 83 / 30 60 60 60
BLAIRSVILLE 62 80 66 80 / 20 30 50 50
CARTERSVILLE 68 85 67 84 / 30 50 60 60
COLUMBUS 72 87 70 84 / 30 60 70 70
GAINESVILLE 68 85 68 83 / 30 50 60 60
MACON 71 88 70 86 / 30 60 70 70
ROME 69 87 68 85 / 30 40 50 60
PEACHTREE CITY 68 86 67 84 / 30 60 60 60
VIDALIA 72 89 72 85 / 30 60 70 70
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...39
LONG TERM...11/03
AVIATION...39
AREA FORECAST DISCUSSION...UPDATE FOR AVIATION
NWS PEACHTREE CITY GA
144 PM EDT SAT AUG 18 2012
.MID MORNING UPDATE...
/ISSUED AT 1042 AM EDT SAT AUG 18 2012/
LATEST SURFACE MAP SHOWS A COLD FRONT NEARLY STALLED ACROSS NORTH
GA...JUST NORTH OF ATLANTA. A NEARLY ZONAL FLOW ALOFT SUGGEST THE
FRONT MAY ONLY SAG SLIGHTLY SOUTHWARD TODAY... AND THIS WOULD PUT IT
OVER METRO ATLANTA DURING DAYTIME HEATING. THE LATEST HRRR MODEL
SHOWS CONVECTION FIRING ALONG THE FRONT RIGHT OVER ATLANTA AREA BY
21-22Z TODAY...WHILE THE LOCAL WRF MODEL SHOWS SCATTERED CONVECTION
NEAR ATLANTA AND SOUTHWARD. ONGOING CONVECTION CURRENTLY PUSHING
ACROSS NE GA AND ANOTHER AREA PUSHING INTO THE LA GRANGE AREA FROM
ALABAMA WILL CONTINUE TO WEAKEN...BUT EXPECT DIFFERENTIAL HEATING
FROM CLOUD FREE AREAS TO THE EAST AND SOUTH OF THIS CONVECTION TO
PROVIDE A FOCUS FOR STORM DEVELOPMENT LATER TODAY...ESPECIALLY AS
WEAK DISTURBANCES ALOFT TRAVERSE THE STATE FRONT THE WEST. MOISTURE
AND INSTABILITY ARE SUFFICIENT TO SUPPORT SCATTERED STORMS WITH A
MODIFIED 12Z SOUNDING SHOWING AROUND 2500 J/KG OF CAPE WITH 1.70
PW`S AND ALMOST -6 LI`S. WILL UPDATE ZONES TO INCREASE POPS TO THE
30-40% RANGE FROM AREAS JUST NORTH OF ATLANTA SOUTHWARD THROUGH THE
AFTERNOON AND HOLD ONTO A LOW CHANCE ACROSS PARTS OF CENTRAL GA
THROUGH THE EVENING HOURS. WITH THE FRONT STALLING ACROSS THE AREA
OVERNIGHT... WILL ALSO HOLD ONTO A SLIGHT CHANCE POP MOST AREAS
OVERNIGHT. AT THIS TIME... NOT EXPECTING SEVERE...BUT CANNOT RULE
OUT A FEW STRONG STORMS PRODUCING 45 MPH WIND GUSTS...SMALL HAIL AND
FREQUENT LIGHTNING. THE STRONG STORM THREAT SHOULD GREATLY DIMINISH
BY 9-10 PM THIS EVENING WITH LOSS OF HEATING.
.PREVIOUS DISCUSSIONS ISSUED AT 426 AM EDT SAT AUG 18 2012/...
SHORT TERM /TODAY THROUGH SUNDAY/...
COLD FRONT CONTINUES TO SAG SOUTH AND EASTWARD...AND RADAR SHOWING A
FEW SHOWERS ALONG BOUNDARY OVER NORTHERN ALABAMA AND EASTERN
TENNESSEE. SOME DEVELOPMENT HAS STARTED IN NORTHERN GEORGIA. MODELS
SHOWING SOMEWHAT DIFFERENT SOLUTIONS...IN THAT THE NAM WEAKENS THE
BOUNDARY WITH LITTLE MOISTURE OVER THE AREA TODAY. AS SHORT WAVES
MOVE ALONG THE BOUNDARY AND TOWARD THE COAST...IT OFFERS LITTLE
CHANCE OF PRECIP. SUNDAY ANOTHER WAVE MOVES ALONG THE BOUNDARY
BRINGING A GREATER ABUNDANCE OF MOISTURE TO THE AREA SUNDAY...AT
LEAST TO CENTRAL GEORGIA...WHILE THE AIR MASS REMAINS RELATIVELY DRY
OVER THE NORTH. THIS WEAK RIDGE OF HIGH PRESSURE IN THE LOWER
EASTERN TENNESSEE VALLEY PUSHES A DRIER AIR MASS INTO NORTH GEORGIA
WHILE MOISTURE LINGERS TO THE SOUTH. THE GFS HAS THE FRONT MOVING IN
THIS MORNING AS WELL BUT WITH A DRIER AIR MASS BEHIND IT TOO.
HOWEVER...GFS HAS THE MOISTURE INCREASING FOR SUNDAY INTO SUNDAY
NIGHT WITH NO DRY AIR INVASION FROM THE NORTH.
GREAT UNCERTAINTY WITH THIS FORECAST BEYOND TODAY. THE THINKING IS
THAT THE FRONT...THOUGH WEAKENING WILL PUSH INTO GEORGIA AND STALL
OVER MIDDLE GEORGIA THIS AFTERNOON TO GIVE A CHANCE OF SHOWERS...
POSSIBLY THUNDERSTORMS FOR THE AREA. SOME SHOWERS ARE ALSO POSSIBLE
ALONG THE FRONT AT IT MAKES ITS WAY SOUTH.
MOS TEMPERATURES LOOK TO BE CLOSE IN AGREEMENT WITH PREVIOUSLY
OBSERVED TEMPERATURES. HENCE...LITTLE CHANGE FROM MOS
TEMPERATURES.
37
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
CWA REMAINS UNDER THE INFLUENCE OF A LONGWAVE TROUGH AT THE
BEGINNING OF THE LONG TERM. LATEST GUIDANCE STILL BRINGS A WAVE
ACROSS THE CWA NEAR THE BEGINNING OF THE LONG TERM BUT ABOUT 12
HOURS EARLIER THAN SUGGESTED YESTERDAY WITH MODELS SHOWING SUNDAY
NIGHT NOW. ALTHOUGH NAM/GFS/ECMWF/SREF SHOW SOME REFLECTION OF A SFC
LOW ASSOCIATED WITH THIS DISTURBANCE...THE GFS IS BY FAR THE
STRONGEST AND APPEARS TO BE OVERDONE ON STRENGTH AND PRECIP. AT
LEAST THROUGH MONDAY...LEANED TOWARD THE NAM/ECMWF SOLUTION TO
ACCOUNT FOR THE OVERDONE GFS. MAIN IMPACT WAS TO POPS THAT ARE IN
THE SLIGHT CHANCE TO LIKELY CATEGORY THROUGH MONDAY AS OPPOSED TO
THE LIKELY AND CATEGORICAL POPS SUGGESTED BY THE GFS. AFTER THE
INFLUENCES FROM THE WAVE ON MONDAY MOVES OUT OF THE CWA...RAIN
CHANCES DECREASE. BEST MOISTURE REMAINS ACROSS SOUTHERN HALF OF CWA
SO HAVE CONTINUED TO SHOW BEST POPS ACROSS THAT AREA. BY
MIDWEEK...LONGWAVE TROUGH CONTINUES TO BREAK DOWN ACROSS THE AREA
AND BEST MOISTURE CONTINUES TO SHIFT OFF TO THE EAST AS HIGH
PRESSURE PUSHES INTO THE CWA AT THE SFC. THIS WILL HELP TO LIMIT
POPS TO SLIGHT CHANCE ACROSS THE NORTH AND CHANCE ACROSS THE
SOUTHERN HALF OF THE CWA.
MEX MAX TEMPS ARE SLIGHTLY HIGHER THAN PREVIOUS RUN. LIKE THIS TREND
AND HAVE EVEN NUDGED MAX TEMPS UP A DEGREE IN SOME PLACES. MIN TEMPS
APPEAR A LITTLE COOL DURING THE WORK WEEK...SO HAD TO MAKE SOME
ADJUSTMENTS UPWARD HERE TOO.
11
&&
.AVIATION...
18Z UPDATE...
VFR CONDITIONS CURRENTLY OVER ALL TAF SITES AND EXPECTED TO PREVAIL
THROUGH THE TAF PERIOD. A COLD FRONT REMAINS NEARLY STATIONARY
ACROSS THE ATLANTA METRO AREA... AND WITH AN ACTIVE WESTERLY FLOW
ALOFT...EXPECT ANOTHER ROUND OF SCATTERED CONVECTION BY LATE
AFTERNOON-EARLY EVENING. LATEST HRRR MODEL INDICATES CONVECTION WILL
FIRE NEAR THE FRONT AND BRUSH THE ATLANTA AREA TAF SITES BY
21-23Z...BUT KEEPS THE MAIN CONVECTION JUST SOUTH OF ATL. WILL PLAY
IT SAFE AND CONTINUE TO SHOW TEMPO -TSRA 21-24Z FOR ALL TAF SITES
TODAY. MODELS AGREE ON WIDESPREAD CONVECTION MOVING IN LATE TONIGHT
AND PREVAILING ON SUNDAY. WILL SHOW VCSH BY 09Z...AND PREVAILING
-SHRA BY 12Z WITH PROB30 -TSRA 12-19Z SUN FOR NOW. WINDS WILL REMAIN
MAINLY WESTERLY AT 8KTS OR LESS.
//ATL CONFIDENCE...
18Z UPDATE...
MODERATE CONFIDENCE ON CONVECTION AND TIMING. HIGH CONFIDENCE ON
ALL OTHER ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 89 69 89 67 / 20 10 50 50
ATLANTA 86 70 85 69 / 20 20 50 40
BLAIRSVILLE 82 60 80 64 / 20 10 20 50
CARTERSVILLE 87 65 86 65 / 20 20 40 40
COLUMBUS 90 72 90 70 / 20 20 50 50
GAINESVILLE 85 68 85 67 / 20 10 40 50
MACON 91 72 91 70 / 20 20 50 50
ROME 88 66 88 66 / 20 20 40 30
PEACHTREE CITY 86 68 87 67 / 20 20 50 40
VIDALIA 91 73 90 72 / 20 20 40 50
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...37
LONG TERM....11
AVIATION...37
AREA FORECAST DISCUSSION...UPDATE
NWS PEACHTREE CITY GA
1042 AM EDT SAT AUG 18 2012
.MID MORNING UPDATE...
LATEST SURFACE MAP SHOWS A COLD FRONT NEARLY STALLED ACROSS NORTH
GA...JUST NORTH OF ATLANTA. A NEARLY ZONAL FLOW ALOFT SUGGEST THE
FRONT MAY ONLY SAG SLIGHTLY SOUTHWARD TODAY... AND THIS WOULD PUT IT
OVER METRO ATLANTA DURING DAYTIME HEATING. THE LATEST HRRR MODEL
SHOWS CONVECTION FIRING ALONG THE FRONT RIGHT OVER ATLANTA AREA BY
21-22Z TODAY...WHILE THE LOCAL WRF MODEL SHOWS SCATTERED CONVECTION
NEAR ATLANTA AND SOUTHWARD. ONGOING CONVECTION CURRENTLY PUSHING
ACROSS NE GA AND ANOTHER AREA PUSHING INTO THE LA GRANGE AREA FROM
ALABAMA WILL CONTINUE TO WEAKEN...BUT EXPECT DIFFERENTIAL HEATING
FROM CLOUD FREE AREAS TO THE EAST AND SOUTH OF THIS CONVECTION TO
PROVIDE A FOCUS FOR STORM DEVELOPMENT LATER TODAY...ESPECIALLY AS
WEAK DISTURBANCES ALOFT TRAVERSE THE STATE FRONT THE WEST. MOISTURE
AND INSTABILITY ARE SUFFICIENT TO SUPPORT SCATTERED STORMS WITH A
MODIFIED 12Z SOUNDING SHOWING AROUND 2500 J/KG OF CAPE WITH 1.70
PW`S AND ALMOST -6 LI`S. WILL UPDATE ZONES TO INCREASE POPS TO THE
30-40% RANGE FROM AREAS JUST NORTH OF ATLANTA SOUTHWARD THROUGH THE
AFTERNOON AND HOLD ONTO A LOW CHANCE ACROSS PARTS OF CENTRAL GA
THROUGH THE EVENING HOURS. WITH THE FRONT STALLING ACROSS THE AREA
OVERNIGHT... WILL ALSO HOLD ONTO A SLIGHT CHANCE POP MOST AREAS
OVERNIGHT. AT THIS TIME... NOT EXPECTING SEVERE...BUT CANNOT RULE
OUT A FEW STRONG STORMS PRODUCING 45 MPH WIND GUSTS...SMALL HAIL AND
FREQUENT LIGHTNING. THE STRONG STORM THREAT SHOULD GREATLY DIMINISH
BY 9-10 PM THIS EVENING WITH LOSS OF HEATING.
.PREVIOUS DISCUSSIONS ISSUED AT 426 AM EDT SAT AUG 18 2012/...
SHORT TERM /TODAY THROUGH SUNDAY/...
COLD FRONT CONTINUES TO SAG SOUTH AND EASTWARD...AND RADAR SHOWING A
FEW SHOWERS ALONG BOUNDARY OVER NORTHERN ALABAMA AND EASTERN
TENNESSEE. SOME DEVELOPMENT HAS STARTED IN NORTHERN GEORGIA. MODELS
SHOWING SOMEWHAT DIFFERENT SOLUTIONS...IN THAT THE NAM WEAKENS THE
BOUNDARY WITH LITTLE MOISTURE OVER THE AREA TODAY. AS SHORT WAVES
MOVE ALONG THE BOUNDARY AND TOWARD THE COAST...IT OFFERS LITTLE
CHANCE OF PRECIP. SUNDAY ANOTHER WAVE MOVES ALONG THE BOUNDARY
BRINGING A GREATER ABUNDANCE OF MOISTURE TO THE AREA SUNDAY...AT
LEAST TO CENTRAL GEORGIA...WHILE THE AIR MASS REMAINS RELATIVELY DRY
OVER THE NORTH. THIS WEAK RIDGE OF HIGH PRESSURE IN THE LOWER
EASTERN TENNESSEE VALLEY PUSHES A DRIER AIR MASS INTO NORTH GEORGIA
WHILE MOISTURE LINGERS TO THE SOUTH. THE GFS HAS THE FRONT MOVING IN
THIS MORNING AS WELL BUT WITH A DRIER AIR MASS BEHIND IT TOO.
HOWEVER...GFS HAS THE MOISTURE INCREASING FOR SUNDAY INTO SUNDAY
NIGHT WITH NO DRY AIR INVASION FROM THE NORTH.
GREAT UNCERTAINTY WITH THIS FORECAST BEYOND TODAY. THE THINKING IS
THAT THE FRONT...THOUGH WEAKENING WILL PUSH INTO GEORGIA AND STALL
OVER MIDDLE GEORGIA THIS AFTERNOON TO GIVE A CHANCE OF SHOWERS...
POSSIBLY THUNDERSTORMS FOR THE AREA. SOME SHOWERS ARE ALSO POSSIBLE
ALONG THE FRONT AT IT MAKES ITS WAY SOUTH.
MOS TEMPERATURES LOOK TO BE CLOSE IN AGREEMENT WITH PREVIOUSLY
OBSERVED TEMPERATURES. HENCE...LITTLE CHANGE FROM MOS
TEMPERATURES.
37
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
CWA REMAINS UNDER THE INFLUENCE OF A LONGWAVE TROUGH AT THE
BEGINNING OF THE LONG TERM. LATEST GUIDANCE STILL BRINGS A WAVE
ACROSS THE CWA NEAR THE BEGINNING OF THE LONG TERM BUT ABOUT 12
HOURS EARLIER THAN SUGGESTED YESTERDAY WITH MODELS SHOWING SUNDAY
NIGHT NOW. ALTHOUGH NAM/GFS/ECMWF/SREF SHOW SOME REFLECTION OF A SFC
LOW ASSOCIATED WITH THIS DISTURBANCE...THE GFS IS BY FAR THE
STRONGEST AND APPEARS TO BE OVERDONE ON STRENGTH AND PRECIP. AT
LEAST THROUGH MONDAY...LEANED TOWARD THE NAM/ECMWF SOLUTION TO
ACCOUNT FOR THE OVERDONE GFS. MAIN IMPACT WAS TO POPS THAT ARE IN
THE SLIGHT CHANCE TO LIKELY CATEGORY THROUGH MONDAY AS OPPOSED TO
THE LIKELY AND CATEGORICAL POPS SUGGESTED BY THE GFS. AFTER THE
INFLUENCES FROM THE WAVE ON MONDAY MOVES OUT OF THE CWA...RAIN
CHANCES DECREASE. BEST MOISTURE REMAINS ACROSS SOUTHERN HALF OF CWA
SO HAVE CONTINUED TO SHOW BEST POPS ACROSS THAT AREA. BY
MIDWEEK...LONGWAVE TROUGH CONTINUES TO BREAK DOWN ACROSS THE AREA
AND BEST MOISTURE CONTINUES TO SHIFT OFF TO THE EAST AS HIGH
PRESSURE PUSHES INTO THE CWA AT THE SFC. THIS WILL HELP TO LIMIT
POPS TO SLIGHT CHANCE ACROSS THE NORTH AND CHANCE ACROSS THE
SOUTHERN HALF OF THE CWA.
MEX MAX TEMPS ARE SLIGHTLY HIGHER THAN PREVIOUS RUN. LIKE THIS TREND
AND HAVE EVEN NUDGED MAX TEMPS UP A DEGREE IN SOME PLACES. MIN TEMPS
APPEAR A LITTLE COOL DURING THE WORK WEEK...SO HAD TO MAKE SOME
ADJUSTMENTS UPWARD HERE TOO.
11
&&
.AVIATION...
15Z UPDATE...
SOME SHOWERS OVER NORTHERN GEORGIA HAVE BROUGHT IN CIGS SCT030 TO
BKN045. VFR CONDITIONS CURRENTLY OVER ALL TAF SITES. CONVECTION OVER
ALABAMA EXPECTED TO BRING CLOUDS AND POSSIBLY SHOWERS INTO VICINITY
OF NORTHERN TAFS...IT IT HOLDS TOGETHER. FRONT TO PUSH INTO ATLANTA
AREA DURING THE AFTERNOON... WITH AN ACTIVE WESTERLY FLOW ALOFT.
HRRR MODEL INDICATES CONVECTION WILL FIRE ALONG THE FRONT AND BRUSH
THE ATLANTA AREA TAF SITES BY 21-22Z. WILL UPDATE TO INCLUDE TEMPO
-TSRA 21-00Z FOR ATLANTA AREA TAFS. CSG AND MCN TAFS ALREADY SHOW
AFTN TSRA THREAT.
//ATL CONFIDENCE...
15Z UPDATE...
MODERATE CONFIDENCE ON CONVECTION AND TIMING. HIGH CONFIDENCE ON
ALL OTHER ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 89 69 89 67 / 20 10 50 50
ATLANTA 86 70 85 69 / 20 20 50 40
BLAIRSVILLE 82 60 80 64 / 20 10 20 50
CARTERSVILLE 87 65 86 65 / 20 20 40 40
COLUMBUS 90 72 90 70 / 20 20 50 50
GAINESVILLE 85 68 85 67 / 20 10 40 50
MACON 91 72 91 70 / 20 20 50 50
ROME 88 66 88 66 / 20 20 40 30
PEACHTREE CITY 86 68 87 67 / 20 20 50 40
VIDALIA 91 73 90 72 / 20 20 40 50
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...37
LONG TERM....11
AVIATION...37
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1013 AM CDT SAT AUG 18 2012
.DISCUSSION...
ISSUED 1013 AM CDT SAT AUG 18 2012
MADE A FEW MINOR TWEEKS TO TEMP GRIDS FOR TODAY.
OTHERWISE...FORECAST LOOKS ON TRACK.
HIGH PRESSURE IS CENTERED OVER THE MIDWEST TODAY PROVIDING DRY
CONDITIONS AND CALM WINDS. HIGH CLOUDS ASSOCIATED WITH DYING
MESOSCALE COMPLEX OVER THE CENTRAL MISSOURI VALLEY WILL GRADUALLY
SPREAD INTO THE AREA...BUT SHOULD ONLY HAVE A MINIMAL IMPACT ON TEMPS.
BARKER
&&
.AVIATION...
ISSUED 652 AM CDT SAT AUG 18 2012
SHALLOW GROUND FOG HAS FORMED AT DAYBREAK THIS MORNING IN A FEW
LOCATIONS IN CENTRAL AND EASTERN IL...BUT NOT AT THE TAF SITES. A
FEW SPOTS MAY DIP TOWARD LIFR CONDITIONS WITH FOG BETWEEN 12Z AND
14Z. HOWEVER THIS WILL BE ISOLATED AND SHORT LIVED. THE CHANCES
ARE SLIM THAT THIS WILL OCCUR AT THE TAF SITES IN CENTRAL AND
EASTERN IL...BUT WILL KEEP A CLOSE EYE ON THIS.
OTHERWISE...VFR CONDITIONS WILL PREVAIL THE NEXT 24 HOURS.
FORECAST SOUNDINGS IN BUFKIT AND THE HRRR CLOUD BASE PROG BOTH
INDICATE THAT A FEW CUMULUS ARE POSSIBLE VERY LATE THIS MORNING
AND DURING THE AFTERNOON...PARTICULARLY IN THE EAST CENTRAL IL.
A SHORTWAVE TROF CURRENTLY IN THE NORTHERN PLAINS IS EXPECTED TO
DIG INTO THE MEAN UPPER TROF POSITION EAST OF THE MS RIVER BY THIS
EVENING. THE ATMOSPHERE WILL BE FAIRLY MOISTURE STARVED...BUT
THERE SHOULD BE ENOUGH LIFT TO PRODUCE AT LEAST A BROKEN AC LAYER
AROUND 10K FT OR SO FROM DUSK THROUGH THE OVERNIGHT HOURS.
MILLER
&&
.PREV DISCUSSION...
ISSUED 356 AM CDT SAT AUG 18 2012
RELATIVELY QUIET WEATHER PATTERN OVERALL. HIGH PRESSURE STILL IN
PLACE OVER THE REGION...WITH A EXPANSIVE TROF STRETCHING FROM THE
NRN PLAINS TO THE NRN ATLANTIC COAST. COOLER AIR IN THE REGION AND
VERY LITTLE MOISTURE FOR MUCH OF THE FORECAST. ISSUES WITHIN THE
MODELS CONFINED TO SUNDAY AND SUNDAY NIGHT WITH SOME QPF REPORTED
IN THE NAM AND GFS. HOWEVER...RH FIELDS DO NOT SEEM TO BACK THIS
UP...AND WOULD LIKE TO KEEP THE POPS TO A MIN AT LEAST ONE MORE
RUN. FORECAST A RATHER CONSERVATIVE ONE.
SHORT TERM...TODAY AND TOMORROW...
COOLER AIR REMAINING IN PLACE THROUGH THE WEEKEND AND FIRST
PORTION OF THE WORK WEEK WITH 850MB TEMPS IN THE 11C-13C RANGE AND
SFC TEMPS IN THE UPPER 70S/LOWER 80S WITH PLENTY OF SUNSHINE.
MOISTURE THROUGH THE COLUMN A BIT OF A TRICKY SITUATION. MODELS
PUSHING QPF THROUGH TOMORROW AND INTO MONDAY WITH A WEAK STORM
SYSTEM MOVING INTO THE OHIO RIVER VALLEY ON SUN. HOWEVER...MODEL
SOUNDINGS DO NOT BACK UP THE WIDESPREAD RAINFALL/QPF. KEEPING A
SLIGHT CHANCE IN THE GRIDS FOR SURE...STARTING THE TREND SHOULD
SUBSEQUENT MODEL RUNS BACK IT UP AND BRING THE RH FIELDS AROUND.
OTHERWISE...MAYBE A SPRINKLE MENTION IS ALL THAT WILL BE NEEDED.
SFC LOW AT THIS POINT WELL TO THE SOUTH AND THE EAST IN THE GFS
AND MORE DIFFUSE IN THE NAM TO WARRANT A WIDESPREAD HIGH POP.
LONG TERM...MONDAY THROUGH FRIDAY...
DEEPER EASTERN TROF AND THERMAL TROF MOVES OUT TO THE EAST LATE
WED/THURSDAY...RESULTING IN WARMEST DAY OF THE WEEK FOR THURSDAY.
850MB TEMPS 16-18C IN ECMWF AS THE WARMTH OVER THE WESTERN HALF OF
THE CONUS SHIFTS EAST SLIGHTLY INTO THE MIDWEST. FOR NOW...TEMPS
IN THE EXTENDED ON THU AND FRI IN THE MID-UPPER 80S. SUN ANGLE
DROPPING...LENGTH OF DAY SHORTENING...LESS TIME TO GET INTO THE
90S...THOUGH THE HEAT OVER THE WESTERN HALF OF THE CONUS IS
AVAILABLE AND OPEN AND WILL HAVE TO BE WATCHED CLOSELY. FOR NOW...
ENOUGH REASONS AGAINST TOPPING GUIDANCE...WILL LEAVE THE 80S
ALONE. QUIET FORECAST AS FAR AS POPS...WITH SOME WEAK POPS SHOWING
UP GOING INTO NEXT WEEKEND IN BOTH THE GFS AND THE ECMWF.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
653 AM CDT SAT AUG 18 2012
.DISCUSSION...
ISSUED 356 AM CDT SAT AUG 18 2012
RELATIVELY QUIET WEATHER PATTERN OVERALL. HIGH PRESSURE STILL IN
PLACE OVER THE REGION...WITH A EXPANSIVE TROF STRETCHING FROM THE
NRN PLAINS TO THE NRN ATLANTIC COAST. COOLER AIR IN THE REGION AND
VERY LITTLE MOISTURE FOR MUCH OF THE FORECAST. ISSUES WITHIN THE
MODELS CONFINED TO SUNDAY AND SUNDAY NIGHT WITH SOME QPF REPORTED
IN THE NAM AND GFS. HOWEVER...RH FIELDS DO NOT SEEM TO BACK THIS
UP...AND WOULD LIKE TO KEEP THE POPS TO A MIN AT LEAST ONE MORE
RUN. FORECAST A RATHER CONSERVATIVE ONE.
SHORT TERM...TODAY AND TOMORROW...
COOLER AIR REMAINING IN PLACE THROUGH THE WEEKEND AND FIRST
PORTION OF THE WORK WEEK WITH 850MB TEMPS IN THE 11C-13C RANGE AND
SFC TEMPS IN THE UPPER 70S/LOWER 80S WITH PLENTY OF SUNSHINE.
MOISTURE THROUGH THE COLUMN A BIT OF A TRICKY SITUATION. MODELS
PUSHING QPF THROUGH TOMORROW AND INTO MONDAY WITH A WEAK STORM
SYSTEM MOVING INTO THE OHIO RIVER VALLEY ON SUN. HOWEVER...MODEL
SOUNDINGS DO NOT BACK UP THE WIDESPREAD RAINFALL/QPF. KEEPING A
SLIGHT CHANCE IN THE GRIDS FOR SURE...STARTING THE TREND SHOULD
SUBSEQUENT MODEL RUNS BACK IT UP AND BRING THE RH FIELDS AROUND.
OTHERWISE...MAYBE A SPRINKLE MENTION IS ALL THAT WILL BE NEEDED.
SFC LOW AT THIS POINT WELL TO THE SOUTH AND THE EAST IN THE GFS
AND MORE DIFFUSE IN THE NAM TO WARRANT A WIDESPREAD HIGH POP.
LONG TERM...MONDAY THROUGH FRIDAY...
DEEPER EASTERN TROF AND THERMAL TROF MOVES OUT TO THE EAST LATE
WED/THURSDAY...RESULTING IN WARMEST DAY OF THE WEEK FOR THURSDAY.
850MB TEMPS 16-18C IN ECMWF AS THE WARMTH OVER THE WESTERN HALF OF
THE CONUS SHIFTS EAST SLIGHTLY INTO THE MIDWEST. FOR NOW...TEMPS
IN THE EXTENDED ON THU AND FRI IN THE MID-UPPER 80S. SUN ANGLE
DROPPING...LENGTH OF DAY SHORTENING...LESS TIME TO GET INTO THE
90S...THOUGH THE HEAT OVER THE WESTERN HALF OF THE CONUS IS
AVAILABLE AND OPEN AND WILL HAVE TO BE WATCHED CLOSELY. FOR NOW...
ENOUGH REASONS AGAINST TOPPING GUIDANCE...WILL LEAVE THE 80S
ALONE. QUIET FORECAST AS FAR AS POPS...WITH SOME WEAK POPS SHOWING
UP GOING INTO NEXT WEEKEND IN BOTH THE GFS AND THE ECMWF.
&&
.AVIATION...
ISSUED 652 AM CDT SAT AUG 18 2012
SHALLOW GROUND FOG HAS FORMED AT DAYBREAK THIS MORNING IN A FEW
LOCATIONS IN CENTRAL AND EASTERN IL...BUT NOT AT THE TAF SITES. A
FEW SPOTS MAY DIP TOWARD LIFR CONDITIONS WITH FOG BETWEEN 12Z AND
14Z. HOWEVER THIS WILL BE ISOLATED AND SHORT LIVED. THE CHANCES
ARE SLIM THAT THIS WILL OCCUR AT THE TAF SITES IN CENTRAL AND
EASTERN IL...BUT WILL KEEP A CLOSE EYE ON THIS.
OTHERWISE...VFR CONDITIONS WILL PREVAIL THE NEXT 24 HOURS.
FORECAST SOUNDINGS IN BUFKIT AND THE HRRR CLOUD BASE PROG BOTH
INDICATE THAT A FEW CUMULUS ARE POSSIBLE VERY LATE THIS MORNING
AND DURING THE AFTERNOON...PARTICULARLY IN THE EAST CENTRAL IL.
A SHORTWAVE TROF CURRENTLY IN THE NORTHERN PLAINS IS EXPECTED TO
DIG INTO THE MEAN UPPER TROF POSITION EAST OF THE MS RIVER BY THIS
EVENING. THE ATMOSPHERE WILL BE FAIRLY MOISTURE STARVED...BUT
THERE SHOULD BE ENOUGH LIFT TO PRODUCE AT LEAST A BROKEN AC LAYER
AROUND 10K FT OR SO FROM DUSK THROUGH THE OVERNIGHT HOURS.
MILLER
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1148 AM MDT SAT AUG 18 2012
.UPDATE...
ISSUED AT 1023 AM MDT SAT AUG 18 2012
THUNDERSTORMS HAVE ENDED FOR TODAY AND REMOVED ALL REMAINING POPS.
SHORTWAVE TROUGH HAS MOVED SOUTHEAST AND SUBSIDENCE IS BUILDING
OVER THE FORECAST AREA IN ITS WAKE WITH MOSTLY SUNNY SKIES.
TEMPERATURES SHOULD EASILY REBOUND TO THE LOWER 8OS FOR HIGHS.
UPDATE ISSUED AT 559 AM MDT SAT AUG 18 2012
JUST COMPLETED AN UPDATE. PRECIPITATION IS FURTHER SOUTH AND WEST
THAN MOST GUIDANCE INDICATES. THE LATEST HRRR HAS FINALLY CAUGHT
ONTO THIS AND USED IT FOR THIS UPDATE. HIGHEST CHANCES WILL BE
CONFINED TO THE EAST AND ESPECIALLY THE SOUTH. PRECIPITATION
SHOULD BE DONE BY 18Z. BASED ON LATEST GUIDANCE AND
TRENDS...UPDATED WINDS...DEWPOINTS AND SKY COVER.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 240 AM MDT SAT AUG 18 2012
FORECAST PROBLEMS WILL BE CHANCE OF PRECIPITATION TODAY...LOW
TEMPERATURES TONIGHT...HIGH TEMPERATURES THROUGH THE SHORT TERM...
AND THE NEXT CHANCE OF PRECIPITATION THE BEGINNING OF NEXT WEEK.
SATELLITE SHOWING AN AMPLIFIED/AMPLIFYING PATTERN FROM THE CENTRAL
PACIFIC INTO THE WESTERN ATLANTIC.
THE MODELS INITIALIZED WELL ON THE JET SEGMENT TO OUR NORTH...
ALTHOUGH THE NAM WAS SLIGHTLY WORSE. THE GFS WAS DOING BETTER AT
MID LEVELS. ON THE SURFACE WINDS...THE ECMWF WAS DOING A LITTLE
BETTER THAN THE NAM. ON THE LOW LEVEL THERMAL FIELD...THE GFS AND
ECMWF WERE DOING A LITTLE BETTER THAN THE UKMET AND SREF.
TODAY/TONIGHT...INCOMING UPPER JET AND SHORTWAVE TROUGH/PV ANOMALY
HAVE BEEN CAUSING THUNDERSTORM DEVELOPMENT FOR THE LAST COUPLE OF
HOURS. MODELS ARE HAVING A LITTLE TROUBLE PLACING THE MAIN AXIS.
OVERALL THEY TEND TO PUT IT TOO FAR NORTH AND EAST. MOST IF NOT ALL
OF THE LIFT WILL PUSH THROUGH BY 18Z. CURRENT GRIDS ADJUSTED BY THE
EVENING SHIFT ARE CAPTURING CURRENT STORMS AND TRENDS WELL AND WILL
LEAVE ALONE AT THIS TIME. WILL MAKE FURTHER ENHANCEMENTS AS TIME
PERMITS.
SHOULD SEE FAIRLY RAPIDLY CLEARING BEHIND STORMS. CURRENT CLOUD
COVER IS HOLDING UP MINS AS WELL SO THEY MAY NOT HAVE THAT FAR TO
GO. TENDED TO DO A BLEND OF THE WARMEST/COOLEST GUIDANCE NEAR THE
CONSENSUS OF MOST OF THE GUIDANCE. IF CLOUD COVER LASTS LONGER...
MAXES WILL HAVE TO BE ADJUSTED DOWN.
JET AND LINGERING LIFT HANG AROUND THROUGH THE NIGHT WHICH MAY
CREATE SPOTTY CLOUD COVER. LIGHT AND VARIABLE WINDS AND LOWER
DEWPOINTS WILL ALLOW TEMPERATURES WILL DROP RAPIDLY. LOWERED MINS
BUT DAY SHIFT WILL HAVE TO TAKE A LOOK AT AGAIN. DO NOT HAVE TIME TO
PUT A CLIMATE SECTION IN BUT RECORD LOWS LOOK TO BE THREATENED
TONIGHT OVER THE ENTIRE AREA.
SUNDAY...WEAK JET SEGMENT LOOKS TO STAY OVER THE AREA THROUGH THE
DAY. LEFT FRONT QUADRANT LOOKS TO AFFECT THE WESTERN AREA IN THE
AFTERNOON. HOWEVER LOOKS TO DO NOTHING WITH AN EXTREMELY AIR MASS
OVER THE AREA. SO LOOK TO HAVE PLENTY OF SUN BUT EASTERLY WINDS AS
THE SURFACE RIDGE MOVES THROUGH. FOLLOWED A CON OF
TEMPERATURE GUIDANCE THAT FELL BETWEEN THE TWO EXTREMES.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 240 AM MDT SAT AUG 18 2012
SUNDAY NIGHT...ABOVE MENTIONED JET SEGMENT MOVES ACROSS THE AREA
WITH THE RIGHT REAR QUADRANT AFFECTING THE WESTERN HALF TO TWO
THIRDS BY LATE IN THE NIGHT. AGAIN LOOKS LIKE ONLY CLOUDS SINCE
THERE IS A DEEP DRY LAYER AT THE BOTTOM. WINDS ARE SLOW TO COME UP
WITH THE POTENTIAL FOR RATHER COOL MINS ONCE AGAIN.
MONDAY/MONDAY NIGHT...RIGHT REAR QUADRANT STARTS THE DAY OVER THE
AREA AND MOVES EAST OF THE AREA BY MID AFTERNOON. A LEFT FRONT
QUADRANT WILL BEGIN TO AFFECT THE AREA BY LATE EVENING AS IT BEGINS
TO MOVE ACROSS THE AREA. THE MAIN MID LEVEL LIFT LOOKS TO MOVE IN
FROM THE NORTHWEST LATE IN THE DAY. ALL THIS LIFT TENDS TO AFFECT
THE SOUTHWEST HALF TO TWO THIRDS OF THE OTHER WHICH IS A SOUTHWARD
SHIFT SINCE YESTERDAY. ANOTHER PROBLEM IS THAT A LOT OF THE MODEL
OUTPUT IS SUFFERING FROM CONVECTIVE FEEDBACK. OVERALL KEPT THE
HIGHER CHANCE POPS FURTHER SOUTHWEST. ONLY MADE A SLIGHT ADJUSTMENT
ON MAXES BUT IF CLOUD COVER IS THICKER THAN EXPECTED WILL NEED TO
ADJUST DOWN.
TUESDAY THROUGH FRIDAY...DUE TO SHORT TERM CONCERNS/INCREASING
THUNDERSTORM COVERAGE WAS NOT ABLE TO SPEED A LOT OF TIME ON THIS
PERIOD. LINGERING CONVECTION WILL BE OVER THE AREA TUESDAY. MODELS
ARE DIFFERING FROM EACH OTHER IN HOW THEY HANDLE THE WESTERN
RIDGING AND HOW SHORTWAVE ENERGY COMES OVER THE TOP. GENERAL IDEA IS
A SERIES OF SHORTWAVE TROUGHS WILL BRING CONTINUED CHANCES FOR
THUNDERSTORMS THROUGH FRIDAY WITH WEDNESDAY AND THURSDAY HAVING THE
GREATEST COVERAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1144 AM MDT SAT AUG 18 2012
VFR CONDITIONS EXPECTED AT BOTH KGLD AND KMCK THROUGH THE TAF
PERIOD. SHORTWAVE TROUGH HAS MOVED SOUTHEAST WITH MUCH DRIER AIR
MOVING IN FROM NEBRASKA.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...024
SHORT TERM...BULLER
LONG TERM...BULLER
AVIATION...024
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1025 AM MDT SAT AUG 18 2012
.UPDATE...
ISSUED AT 1023 AM MDT SAT AUG 18 2012
THUNDERSTORMS HAVE ENDED FOR TODAY AND REMOVED ALL REMAINING POPS.
SHORTWAVE TROUGH HAS MOVED SOUTHEAST AND SUBSIDENCE IS BUILDING
OVER THE FORECAST AREA IN ITS WAKE WITH MOSTLY SUNNY SKIES.
TEMPERATURES SHOULD EASILY REBOUND TO THE LOWER 8OS FOR HIGHS.
UPDATE ISSUED AT 559 AM MDT SAT AUG 18 2012
JUST COMPLETED AN UPDATE. PRECIPITATION IS FURTHER SOUTH AND WEST
THAN MOST GUIDANCE INDICATES. THE LATEST HRRR HAS FINALLY CAUGHT
ONTO THIS AND USED IT FOR THIS UPDATE. HIGHEST CHANCES WILL BE
CONFINED TO THE EAST AND ESPECIALLY THE SOUTH. PRECIPITATION
SHOULD BE DONE BY 18Z. BASED ON LATEST GUIDANCE AND
TRENDS...UPDATED WINDS...DEWPOINTS AND SKY COVER.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 240 AM MDT SAT AUG 18 2012
FORECAST PROBLEMS WILL BE CHANCE OF PRECIPITATION TODAY...LOW
TEMPERATURES TONIGHT...HIGH TEMPERATURES THROUGH THE SHORT TERM...
AND THE NEXT CHANCE OF PRECIPITATION THE BEGINNING OF NEXT WEEK.
SATELLITE SHOWING AN AMPLIFIED/AMPLIFYING PATTERN FROM THE CENTRAL
PACIFIC INTO THE WESTERN ATLANTIC.
THE MODELS INITIALIZED WELL ON THE JET SEGMENT TO OUR NORTH...
ALTHOUGH THE NAM WAS SLIGHTLY WORSE. THE GFS WAS DOING BETTER AT
MID LEVELS. ON THE SURFACE WINDS...THE ECMWF WAS DOING A LITTLE
BETTER THAN THE NAM. ON THE LOW LEVEL THERMAL FIELD...THE GFS AND
ECMWF WERE DOING A LITTLE BETTER THAN THE UKMET AND SREF.
TODAY/TONIGHT...INCOMING UPPER JET AND SHORTWAVE TROUGH/PV ANOMALY
HAVE BEEN CAUSING THUNDERSTORM DEVELOPMENT FOR THE LAST COUPLE OF
HOURS. MODELS ARE HAVING A LITTLE TROUBLE PLACING THE MAIN AXIS.
OVERALL THEY TEND TO PUT IT TOO FAR NORTH AND EAST. MOST IF NOT ALL
OF THE LIFT WILL PUSH THROUGH BY 18Z. CURRENT GRIDS ADJUSTED BY THE
EVENING SHIFT ARE CAPTURING CURRENT STORMS AND TRENDS WELL AND WILL
LEAVE ALONE AT THIS TIME. WILL MAKE FURTHER ENHANCEMENTS AS TIME
PERMITS.
SHOULD SEE FAIRLY RAPIDLY CLEARING BEHIND STORMS. CURRENT CLOUD
COVER IS HOLDING UP MINS AS WELL SO THEY MAY NOT HAVE THAT FAR TO
GO. TENDED TO DO A BLEND OF THE WARMEST/COOLEST GUIDANCE NEAR THE
CONSENSUS OF MOST OF THE GUIDANCE. IF CLOUD COVER LASTS LONGER...
MAXES WILL HAVE TO BE ADJUSTED DOWN.
JET AND LINGERING LIFT HANG AROUND THROUGH THE NIGHT WHICH MAY
CREATE SPOTTY CLOUD COVER. LIGHT AND VARIABLE WINDS AND LOWER
DEWPOINTS WILL ALLOW TEMPERATURES WILL DROP RAPIDLY. LOWERED MINS
BUT DAY SHIFT WILL HAVE TO TAKE A LOOK AT AGAIN. DO NOT HAVE TIME TO
PUT A CLIMATE SECTION IN BUT RECORD LOWS LOOK TO BE THREATENED
TONIGHT OVER THE ENTIRE AREA.
SUNDAY...WEAK JET SEGMENT LOOKS TO STAY OVER THE AREA THROUGH THE
DAY. LEFT FRONT QUADRANT LOOKS TO AFFECT THE WESTERN AREA IN THE
AFTERNOON. HOWEVER LOOKS TO DO NOTHING WITH AN EXTREMELY AIR MASS
OVER THE AREA. SO LOOK TO HAVE PLENTY OF SUN BUT EASTERLY WINDS AS
THE SURFACE RIDGE MOVES THROUGH. FOLLOWED A CON OF
TEMPERATURE GUIDANCE THAT FELL BETWEEN THE TWO EXTREMES.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 240 AM MDT SAT AUG 18 2012
SUNDAY NIGHT...ABOVE MENTIONED JET SEGMENT MOVES ACROSS THE AREA
WITH THE RIGHT REAR QUADRANT AFFECTING THE WESTERN HALF TO TWO
THIRDS BY LATE IN THE NIGHT. AGAIN LOOKS LIKE ONLY CLOUDS SINCE
THERE IS A DEEP DRY LAYER AT THE BOTTOM. WINDS ARE SLOW TO COME UP
WITH THE POTENTIAL FOR RATHER COOL MINS ONCE AGAIN.
MONDAY/MONDAY NIGHT...RIGHT REAR QUADRANT STARTS THE DAY OVER THE
AREA AND MOVES EAST OF THE AREA BY MID AFTERNOON. A LEFT FRONT
QUADRANT WILL BEGIN TO AFFECT THE AREA BY LATE EVENING AS IT BEGINS
TO MOVE ACROSS THE AREA. THE MAIN MID LEVEL LIFT LOOKS TO MOVE IN
FROM THE NORTHWEST LATE IN THE DAY. ALL THIS LIFT TENDS TO AFFECT
THE SOUTHWEST HALF TO TWO THIRDS OF THE OTHER WHICH IS A SOUTHWARD
SHIFT SINCE YESTERDAY. ANOTHER PROBLEM IS THAT A LOT OF THE MODEL
OUTPUT IS SUFFERING FROM CONVECTIVE FEEDBACK. OVERALL KEPT THE
HIGHER CHANCE POPS FURTHER SOUTHWEST. ONLY MADE A SLIGHT ADJUSTMENT
ON MAXES BUT IF CLOUD COVER IS THICKER THAN EXPECTED WILL NEED TO
ADJUST DOWN.
TUESDAY THROUGH FRIDAY...DUE TO SHORT TERM CONCERNS/INCREASING
THUNDERSTORM COVERAGE WAS NOT ABLE TO SPEED A LOT OF TIME ON THIS
PERIOD. LINGERING CONVECTION WILL BE OVER THE AREA TUESDAY. MODELS
ARE DIFFERING FROM EACH OTHER IN HOW THEY HANDLE THE WESTERN
RIDGING AND HOW SHORTWAVE ENERGY COMES OVER THE TOP. GENERAL IDEA IS
A SERIES OF SHORTWAVE TROUGHS WILL BRING CONTINUED CHANCES FOR
THUNDERSTORMS THROUGH FRIDAY WITH WEDNESDAY AND THURSDAY HAVING THE
GREATEST COVERAGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 559 AM MDT SAT AUG 18 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. THUNDERSTORMS WILL
STAY TO THE SOUTH AND EAST OF KMCK. CURRENT AREA OF THUNDERSTORMS
WILL AFFECT KGLD FOR A COUPLE MORE HOURS BEFORE ENDING. AS SKIES
CLEAR AND SUBSIDENCE OCCURS BEHIND AREA OF STORMS...WINDS WILL
SHIFT TO THE NORTH AND BECOME GUSTY UNTIL EARLY EVENING BEFORE
BECOMING LIGHT AND VARIABLE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...024
SHORT TERM...BULLER
LONG TERM...BULLER
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
607 AM MDT SAT AUG 18 2012
.UPDATE...
ISSUED AT 559 AM MDT SAT AUG 18 2012
JUST COMPLETED AN UPDATE. PRECIPITATION IS FURTHER SOUTH AND WEST
THAN MOST GUIDANCE INDICATES. THE LATEST HRRR HAS FINALLY CAUGHT
ONTO THIS AND USED IT FOR THIS UPDATE. HIGHEST CHANCES WILL BE
CONFINED TO THE EAST AND ESPECIALLY THE SOUTH. PRECIPITATION
SHOULD BE DONE BY 18Z. BASED ON LATEST GUIDANCE AND
TRENDS...UPDATED WINDS...DEWPOINTS AND SKY COVER.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 240 AM MDT SAT AUG 18 2012
FORECAST PROBLEMS WILL BE CHANCE OF PRECIPITATION TODAY...LOW
TEMPERATURES TONIGHT...HIGH TEMPERATURES THROUGH THE SHORT TERM...
AND THE NEXT CHANCE OF PRECIPITATION THE BEGINNING OF NEXT WEEK.
SATELLITE SHOWING AN AMPLIFIED/AMPLIFYING PATTERN FROM THE CENTRAL
PACIFIC INTO THE WESTERN ATLANTIC.
THE MODELS INITIALIZED WELL ON THE JET SEGMENT TO OUR NORTH...
ALTHOUGH THE NAM WAS SLIGHTLY WORSE. THE GFS WAS DOING BETTER AT
MID LEVELS. ON THE SURFACE WINDS...THE ECMWF WAS DOING A LITTLE
BETTER THAN THE NAM. ON THE LOW LEVEL THERMAL FIELD...THE GFS AND
ECMWF WERE DOING A LITTLE BETTER THAN THE UKMET AND SREF.
TODAY/TONIGHT...INCOMING UPPER JET AND SHORTWAVE TROUGH/PV ANOMALY
HAVE BEEN CAUSING THUNDERSTORM DEVELOPMENT FOR THE LAST COUPLE OF
HOURS. MODELS ARE HAVING A LITTLE TROUBLE PLACING THE MAIN AXIS.
OVERALL THEY TEND TO PUT IT TOO FAR NORTH AND EAST. MOST IF NOT ALL
OF THE LIFT WILL PUSH THROUGH BY 18Z. CURRENT GRIDS ADJUSTED BY THE
EVENING SHIFT ARE CAPTURING CURRENT STORMS AND TRENDS WELL AND WILL
LEAVE ALONE AT THIS TIME. WILL MAKE FURTHER ENHANCEMENTS AS TIME
PERMITS.
SHOULD SEE FAIRLY RAPIDLY CLEARING BEHIND STORMS. CURRENT CLOUD
COVER IS HOLDING UP MINS AS WELL SO THEY MAY NOT HAVE THAT FAR TO
GO. TENDED TO DO A BLEND OF THE WARMEST/COOLEST GUIDANCE NEAR THE
CONSENSUS OF MOST OF THE GUIDANCE. IF CLOUD COVER LASTS LONGER...
MAXES WILL HAVE TO BE ADJUSTED DOWN.
JET AND LINGERING LIFT HANG AROUND THROUGH THE NIGHT WHICH MAY
CREATE SPOTTY CLOUD COVER. LIGHT AND VARIABLE WINDS AND LOWER
DEWPOINTS WILL ALLOW TEMPERATURES WILL DROP RAPIDLY. LOWERED MINS
BUT DAY SHIFT WILL HAVE TO TAKE A LOOK AT AGAIN. DO NOT HAVE TIME TO
PUT A CLIMATE SECTION IN BUT RECORD LOWS LOOK TO BE THREATENED
TONIGHT OVER THE ENTIRE AREA.
SUNDAY...WEAK JET SEGMENT LOOKS TO STAY OVER THE AREA THROUGH THE
DAY. LEFT FRONT QUADRANT LOOKS TO AFFECT THE WESTERN AREA IN THE
AFTERNOON. HOWEVER LOOKS TO DO NOTHING WITH AN EXTREMELY AIR MASS
OVER THE AREA. SO LOOK TO HAVE PLENTY OF SUN BUT EASTERLY WINDS AS
THE SURFACE RIDGE MOVES THROUGH. FOLLOWED A CON OF
TEMPERATURE GUIDANCE THAT FELL BETWEEN THE TWO EXTREMES.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 240 AM MDT SAT AUG 18 2012
SUNDAY NIGHT...ABOVE MENTIONED JET SEGMENT MOVES ACROSS THE AREA
WITH THE RIGHT REAR QUADRANT AFFECTING THE WESTERN HALF TO TWO
THIRDS BY LATE IN THE NIGHT. AGAIN LOOKS LIKE ONLY CLOUDS SINCE
THERE IS A DEEP DRY LAYER AT THE BOTTOM. WINDS ARE SLOW TO COME UP
WITH THE POTENTIAL FOR RATHER COOL MINS ONCE AGAIN.
MONDAY/MONDAY NIGHT...RIGHT REAR QUADRANT STARTS THE DAY OVER THE
AREA AND MOVES EAST OF THE AREA BY MID AFTERNOON. A LEFT FRONT
QUADRANT WILL BEGIN TO AFFECT THE AREA BY LATE EVENING AS IT BEGINS
TO MOVE ACROSS THE AREA. THE MAIN MID LEVEL LIFT LOOKS TO MOVE IN
FROM THE NORTHWEST LATE IN THE DAY. ALL THIS LIFT TENDS TO AFFECT
THE SOUTHWEST HALF TO TWO THIRDS OF THE OTHER WHICH IS A SOUTHWARD
SHIFT SINCE YESTERDAY. ANOTHER PROBLEM IS THAT A LOT OF THE MODEL
OUTPUT IS SUFFERING FROM CONVECTIVE FEEDBACK. OVERALL KEPT THE
HIGHER CHANCE POPS FURTHER SOUTHWEST. ONLY MADE A SLIGHT ADJUSTMENT
ON MAXES BUT IF CLOUD COVER IS THICKER THAN EXPECTED WILL NEED TO
ADJUST DOWN.
TUESDAY THROUGH FRIDAY...DUE TO SHORT TERM CONCERNS/INCREASING
THUNDERSTORM COVERAGE WAS NOT ABLE TO SPEED A LOT OF TIME ON THIS
PERIOD. LINGERING CONVECTION WILL BE OVER THE AREA TUESDAY. MODELS
ARE DIFFERING FROM EACH OTHER IN HOW THEY HANDLE THE WESTERN
RIDGING AND HOW SHORTWAVE ENERGY COMES OVER THE TOP. GENERAL IDEA IS
A SERIES OF SHORTWAVE TROUGHS WILL BRING CONTINUED CHANCES FOR
THUNDERSTORMS THROUGH FRIDAY WITH WEDNESDAY AND THURSDAY HAVING THE
GREATEST COVERAGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 559 AM MDT SAT AUG 18 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. THUNDERSTORMS WILL
STAY TO THE SOUTH AND EAST OF KMCK. CURRENT AREA OF THUNDERSTORMS
WILL AFFECT KGLD FOR A COUPLE MORE HOURS BEFORE ENDING. AS SKIES
CLEAR AND SUBSIDENCE OCCURS BEHIND AREA OF STORMS...WINDS WILL
SHIFT TO THE NORTH AND BECOME GUSTY UNTIL EARLY EVENING BEFORE
BECOMING LIGHT AND VARIABLE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...BULLER
LONG TERM...BULLER
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
638 AM CDT SAT AUG 18 2012
...UPDATED FOR AVIATION DISCUSSION...
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 230 AM CDT SAT AUG 18 2012
A LARGE UPPER-LEVEL TROUGH WAS CENTERED OVER THE GREAT LAKES REGION
EARLY THIS MORNING. A SHORTWAVE TROUGH HAS ALREADY ROTATED AROUND
THIS FEATURE AND PUSHED A COLD FRONT INTO THE SOUTHERN PLAINS. THE
WESTERN END OF THIS FRONT PUSHED BACK NORTHWARD INTO NORTHEAST NEW MEXICO
FRIDAY AFTERNOON WHERE SURFACE BASED CONVECTION DEVELOPED. SURFACE
LOW PRESSURE WAS DEVELOPING IN EASTERN COLORADO AS OF 3 AM IN RESPONSE
TO THE NEXT ROBUST SHORTWAVE TROUGH THAT WAS DIVING SOUTHEASTWARD
INTO THE NORTHERN PLAINS ON THE BACK SIDE OF THE GREAT LAKES
LONGWAVE TROUGH.
A LOW LEVEL JET HAD DEVELOPED EARLY THIS MORNING IN RESPONSE TO THE
APPROACHING SHORTWAVE TROUGH. STRONG THETA-E ADVECTION WAS LOCATED
ACROSS FAR WESTERN KANSAS AND WAS PROGRESSING NORTHEASTWARD. NAM
SOUNDINGS VALID FOR 12Z SHOW 1800-2400 J/KG OF ELEVATED CAPE AS FAR
EAST AS CIMARRON AND SCOTT CITY. THUNDERSTORMS WERE ALREADY DEVELOPING
IN THE WARM ADVECTION REGIME ALONG THE EDGE OF THE MID LEVEL CAPPING
INVERSION AS OF 230 AM. ADDITIONAL STORMS WILL DEVELOP AND
PROPAGATE SOUTHEASTWARD WITH THE MID-LEVEL FLOW. THE HRRR AND NAM
INDICATE THAT THE BEST CHANCE OF THUNDERSTORMS WILL BE ALONG AN
AXIS FROM SCOTT CITY TO NESS CITY TO DODGE CITY TO COLDWATER.
PRECIPITATION CHANCES WERE RAISED TO 60-70% IN THIS CORRIDOR.
GIVEN THE ELEVATED SHEAR AND MODERATE ELEVATED CAPE, SEVERE STORMS
ARE POSSIBLE WITH HAIL AS LARGE AS HALF DOLLARS.
THE CONVECTIVE CLUSTER WILL BE SLOW TO EXIT SOUTHERN KANSAS THIS
AFTERNOON SO THAT SOUTHEASTERLY OUTFLOW IN THE WAKE OF THE STORMS
WILL TEND TO KEEP COOL AIR IN PLACE EVEN IF SOME CLEARING OCCURS.
HOWEVER, IF THE MORNING STORM CLUSTER MOVES THROUGH FAST ENOUGH,
THEN DESTABILIZATION COULD LEAD TO RENEWED THUNDERSTORMS BY
MID-AFTERNOON SINCE THE COLD FRONT WILL NOT HAVE PASSED YET. THESE
STORMS COULD BE SURFACE BASED AND COULD ALSO BE SEVERE. HIGH
TEMPERATURES WERE LOWERED SEVERAL DEGREES, ESPECIALLY FROM DODGE
CITY SOUTH AND EAST AND ACTUAL HIGHS WILL PROBABLY OCCUR TOWARD 6-7
PM.
THE COLD FRONT ASSOCIATED WITH THIS UPPER-LEVEL SYSTEM WILL PASS
THROUGH LATE THIS EVENING. CLEARING WILL OCCUR LATE TONIGHT IN
THE WAKE OF THIS SYSTEM WITH SUBSIDING WINDS TOWARD SUNRISE. THE
COOLEST TEMPERATURES OF THE SEASON ARE POSSIBLE, WITH SOME UPPER
40S NOT OUT OF THE QUESTION NEAR SCOTT CITY. SLIGHTLY WARMER MINIMUM
TEMPERATURES IN THE LOWER TO MID 50S ARE EXPECTED AT GARDEN CITY AND
DODGE CITY.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 228 AM CDT SAT AUG 18 2012
AN AREA OF HIGH PRESSURE AT THE SURFACE WILL SETTLE INTO CENTRAL
PLAINS ON SUNDAY. SKIES WILL CLEAR AND BASED ON 850MB TEMPERATURES
TRENDS BETWEEN 18Z SUNDAY AND 00Z MONDAY THE PREVIOUS FORECAST STILL
APPEARS ON TRACK WITH HIGHS CLIMBING INTO THE LOW TO MID 80S.
A CLEAR AND COOL NIGHT CAN BE EXPECTED SUNDAY NIGHT AS THIS SURFACE
HIGH SLOWLY CROSSES WESTERN AND CENTRAL KANSAS. BASED ON WHERE THE
LIGHTEST WINDS WILL BE BETWEEN 09Z AND 12Z SUNDAY AM LEANING
TOWARDS UNDERCUTTING THE COOLEST GUIDANCE WHILE STAYED CLOSE TO THE
MAV/MET ELSEWHERE.
ON MONDAY THE NEXT UPPER LEVEL DISTURBANCE WILL BEGIN TO CROSS THE
CENTRAL ROCKIES. THE GFS, NAM, AND ECMWF REMAIN IN DECENT AGREEMENT
WITH THIS NEXT SYSTEM EXITING THE ROCKIES AND CROSSING INTO THE
CENTRAL PLAINS LATE MONDAY NIGHT AND TUESDAY. AS THIS SYSTEM
CROSSING INTO THE PLAINS...SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP WITH THE BETTER CHANCES FOR WIDESPREAD
PRECIPITATION BEING LATE MONDAY NIGHT/EARLY TUESDAY BASED ON THE
UPPER LEVEL JET DYNAMICS, 850-700MB MOISTURE AND IMPROVING
FRONTOGENESIS.
ONCE THIS SYSTEM EXITS THE CENTRAL PLAINS AND MOVES TOWARDS THE
LOWER MISSISSIPPI VALLEY THE MID LEVEL FLOW WILL BACK AND BECOME
MORE PERPENDICULAR TO THE ROCKIES. THIS ENHANCED DOWNSLOPE FLOW
SUGGESTS A WARMING TREND MID WEEK AS A TROUGH OF LOW PRESSURE AT THE
SURFACE BEGINS TO DEVELOP ALONG THE LEE OF THE ROCKIES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 632 AM CDT SAT AUG 18 2012
ANOTHER CLUSTER OF THUNDERSTORMS WILL AFFECT GCK/DDC BETWEEN 1230
AND 15 UTC. SOME HEAVY RAIN, WIND GUSTS AS HIGH AS 45 MPH AND
SMALL HAIL ARE POSSIBLE CLOSE TO THESE TERMINALS. OUTSIDE OF THE
STORMS, VFR CONDITIONS WILL PREVAIL. ISOLATED THUNDERSTORMS COULD ALSO
AFFECT THE HYS TERMINAL THROUGH 16 UTC. A COLD FRONT WILL PASS
THROUGH THE TERMINALS BY 03Z, WITH A WIND SHIFT TO THE NORTH.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 79 52 82 54 / 90 20 10 0
GCK 83 51 82 54 / 70 10 10 10
EHA 84 61 83 56 / 30 20 10 10
LBL 80 58 84 55 / 40 20 10 10
HYS 83 49 82 53 / 50 20 10 0
P28 81 59 84 55 / 60 30 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...FINCH
LONG TERM...BURGERT
AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
241 AM CDT SAT AUG 18 2012
...UPDATED FOR SHORT TERM DISCUSSION...
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 230 AM CDT SAT AUG 18 2012
A LARGE UPPER-LEVEL TROUGH WAS CENTERED OVER THE GREAT LAKES REGION
EARLY THIS MORNING. A SHORTWAVE TROUGH HAS ALREADY ROTATED AROUND
THIS FEATURE AND PUSHED A COLD FRONT INTO THE SOUTHERN PLAINS. THE
WESTERN END OF THIS FRONT PUSHED BACK NORTHWARD INTO NORTHEAST NEW MEXICO
FRIDAY AFTERNOON WHERE SURFACE BASED CONVECTION DEVELOPED. SURFACE
LOW PRESSURE WAS DEVELOPING IN EASTERN COLORADO AS OF 3 AM IN RESPONSE
TO THE NEXT ROBUST SHORTWAVE TROUGH THAT WAS DIVING SOUTHEASTWARD
INTO THE NORTHERN PLAINS ON THE BACK SIDE OF THE GREAT LAKES
LONGWAVE TROUGH.
A LOW LEVEL JET HAD DEVELOPED EARLY THIS MORNING IN RESPONSE TO THE
APPROACHING SHORTWAVE TROUGH. STRONG THETA-E ADVECTION WAS LOCATED
ACROSS FAR WESTERN KANSAS AND WAS PROGRESSING NORTHEASTWARD. NAM
SOUNDINGS VALID FOR 12Z SHOW 1800-2400 J/KG OF ELEVATED CAPE AS FAR
EAST AS CIMARRON AND SCOTT CITY. THUNDERSTORMS WERE ALREADY DEVELOPING
IN THE WARM ADVECTION REGIME ALONG THE EDGE OF THE MID LEVEL CAPPING
INVERSION AS OF 230 AM. ADDITIONAL STORMS WILL DEVELOP AND
PROPAGATE SOUTHEASTWARD WITH THE MID-LEVEL FLOW. THE HRRR AND NAM
INDICATE THAT THE BEST CHANCE OF THUNDERSTORMS WILL BE ALONG AN
AXIS FROM SCOTT CITY TO NESS CITY TO DODGE CITY TO COLDWATER.
PRECIPITATION CHANCES WERE RAISED TO 60-70% IN THIS CORRIDOR.
GIVEN THE ELEVATED SHEAR AND MODERATE ELEVATED CAPE, SEVERE STORMS
ARE POSSIBLE WITH HAIL AS LARGE AS HALF DOLLARS.
THE CONVECTIVE CLUSTER WILL BE SLOW TO EXIT SOUTHERN KANSAS THIS
AFTERNOON SO THAT SOUTHEASTERLY OUTFLOW IN THE WAKE OF THE STORMS
WILL TEND TO KEEP COOL AIR IN PLACE EVEN IF SOME CLEARING OCCURS.
HOWEVER, IF THE MORNING STORM CLUSTER MOVES THROUGH FAST ENOUGH,
THEN DESTABILIZATION COULD LEAD TO RENEWED THUNDERSTORMS BY
MID-AFTERNOON SINCE THE COLD FRONT WILL NOT HAVE PASSED YET. THESE
STORMS COULD BE SURFACE BASED AND COULD ALSO BE SEVERE. HIGH
TEMPERATURES WERE LOWERED SEVERAL DEGREES, ESPECIALLY FROM DODGE
CITY SOUTH AND EAST AND ACTUAL HIGHS WILL PROBABLY OCCUR TOWARD 6-7
PM.
THE COLD FRONT ASSOCIATED WITH THIS UPPER-LEVEL SYSTEM WILL PASS
THROUGH LATE THIS EVENING. CLEARING WILL OCCUR LATE TONIGHT IN
THE WAKE OF THIS SYSTEM WITH SUBSIDING WINDS TOWARD SUNRISE. THE
COOLEST TEMPERATURES OF THE SEASON ARE POSSIBLE, WITH SOME UPPER
40S NOT OUT OF THE QUESTION NEAR SCOTT CITY. SLIGHTLY WARMER MINIMUM
TEMPERATURES IN THE LOWER TO MID 50S ARE EXPECTED AT GARDEN CITY AND
DODGE CITY.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 228 AM CDT SAT AUG 18 2012
AN AREA OF HIGH PRESSURE AT THE SURFACE WILL SETTLE INTO CENTRAL
PLAINS ON SUNDAY. SKIES WILL CLEAR AND BASED ON 850MB TEMPERATURES
TRENDS BETWEEN 18Z SUNDAY AND 00Z MONDAY THE PREVIOUS FORECAST STILL
APPEARS ON TRACK WITH HIGHS CLIMBING INTO THE LOW TO MID 80S.
A CLEAR AND COOL NIGHT CAN BE EXPECTED SUNDAY NIGHT AS THIS SURFACE
HIGH SLOWLY CROSSES WESTERN AND CENTRAL KANSAS. BASED ON WHERE THE
LIGHTEST WINDS WILL BE BETWEEN 09Z AND 12Z SUNDAY AM LEANING
TOWARDS UNDERCUTTING THE COOLEST GUIDANCE WHILE STAYED CLOSE TO THE
MAV/MET ELSEWHERE.
ON MONDAY THE NEXT UPPER LEVEL DISTURBANCE WILL BEGIN TO CROSS THE
CENTRAL ROCKIES. THE GFS, NAM, AND ECMWF REMAIN IN DECENT AGREEMENT
WITH THIS NEXT SYSTEM EXITING THE ROCKIES AND CROSSING INTO THE
CENTRAL PLAINS LATE MONDAY NIGHT AND TUESDAY. AS THIS SYSTEM
CROSSING INTO THE PLAINS...SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP WITH THE BETTER CHANCES FOR WIDESPREAD
PRECIPITATION BEING LATE MONDAY NIGHT/EARLY TUESDAY BASED ON THE
UPPER LEVEL JET DYNAMICS, 850-700MB MOISTURE AND IMPROVING
FRONTOGENESIS.
ONCE THIS SYSTEM EXITS THE CENTRAL PLAINS AND MOVES TOWARDS THE
LOWER MISSISSIPPI VALLEY THE MID LEVEL FLOW WILL BACK AND BECOME
MORE PERPENDICULAR TO THE ROCKIES. THIS ENHANCED DOWNSLOPE FLOW
SUGGESTS A WARMING TREND MID WEEK AS A TROUGH OF LOW PRESSURE AT THE
SURFACE BEGINS TO DEVELOP ALONG THE LEE OF THE ROCKIES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1241 AM CDT SAT AUG 18 2012
A CLUSTER OF THUNDERSTORMS IS EXPECTED TO DEVELOP AHEAD OF A
STRONG SHORTWAVE TROUGH TOWARD 12Z OVER NORTHWEST KANSAS AS A LOW LEVEL
JET DEVELOPS AND TRANSPORTS RICH MOISTURE INTO THE CENTRAL HIGH PLAINS.
THESE STORMS ARE EXPECTED TO MOVE SOUTHEAST AND POSSIBLY AFFECT
GCK/DDC/HYS BETWEEN 12 AND 18Z, WITH DDC BEING THE MOST LIKELY
TERMINAL TO BE AFFECTED. AWAY FROM THE THUNDERSTORMS, VFR
CONDITIONS WILL PERSIST. SOME OBSTRUCTION TO VISIBILITIES
IS POSSIBLE WITH ANY AREAS OF HEAVY RAIN. SOME STRONG WIND GUSTS
CANNOT BE RULED OUT BUT ARE NOT THE MAIN THREAT DUE TO THE
ELEVATED NATURE OF THE CONVECTION,
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 76 52 82 52 / 60 10 10 0
GCK 79 51 82 53 / 60 10 10 10
EHA 83 61 83 56 / 30 20 10 10
LBL 80 58 84 54 / 50 20 10 10
HYS 82 49 82 52 / 60 10 10 0
P28 79 59 84 52 / 60 20 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...FINCH
LONG TERM...BURGERT
AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS PADUCAH KY
946 PM CDT SUN AUG 19 2012
.UPDATE...
ISSUED AT 946 PM CDT SUN AUG 19 2012
SCATTERED SHOWERS OVER SOUTHEAST MISSOURI HAVE BEEN RATHER
RESILIENT THIS EVENING. UPDATED THE FORECAST FOR THE THIRD TIME TO
ACCOUNT FOR THEM...AND THIS TIME ENDED UP SPREADING ISOLATED SHOWERS
INTO THE PURCHASE AREA OF WEST KENTUCKY FOR THE NEXT HOUR OR TWO.
HOWEVER...WITH NICE OUTFLOW NOTED ON RADAR...IT APPEARS THEY ARE
FINALLY ON A DOWNWARD TREND.
IN RESPONSE TO THE SHOWERS DEWPOINTS HAVE JUMPED INTO THE
60S...WHICH MAY RESULT IN MILDER LOWS OVER MUCH SOUTHEAST
MISSOURI. THE RUC HAS A DECENT HANDLE ON THE SITUATION...SO
FOLLOWED IT PRETTY CLOSELY. THIS ALSO RESULTED IN A SLIGHT LOWERING
OF LOWS IN THE KEVV AREA.
THE AVIATION SECTION HAS ALSO BEEN UPDATED FOR THE IMPACT OF THE
SHOWERS AT KCGI
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 303 PM CDT SUN AUG 19 2012
BASED GENERALLY ON SAME REASONING AS IN THE UPDATE SECTION ABOVE...
AM INCLINED TO REDUCE SHOWER/STORM CHANCES DOWN TO AROUND 10
PERCENT FOR MONDAY/TUE ALSO. AGAIN...EVEN THO WEAK IMPULSES ALOFT
WILL CONTINUE TO ROTATE SSE WITHIN FAIRLY DEEP TROF /CYCLONIC FLOW/
OVER THE OHIO VALLEY...THERE JUST SEEMS TO BE VERY LITTLE
INSTABILITY AND OVERALL MOISTURE TO WORK WITH///ESP IN THE LOWEST
7000 TO 10000 FT. CANNOT RULE OUT AN ISOLD SHOWER OR SPRINKLES HERE
AND THERE...BUT CAPES PROGGED TO REMAIN LESS THAN 400 J/KG FOR THE
MOST PART THROUGH TUE...SO THUNDER CHCS CONTINUE TO LOOK PRACTICALLY
NIL.
AS FAR AS TEMPS ARE CONCERNED...WILL CONT TO IGNORE THE OBVIOUSLY
COLD MAV TEMP BIAS. EVEN THE MET MOS TEMPS SEEM TO BE RUNNING A
FEW DEGREES TOO COOL TODAY. HOWEVER...GIVEN THE FACT THAT THERE
MAY BE MORE IN THE WAY OF MID CLOUDS MONDAY...WILL STAY CLOSE TO
THE MET MOS NUMBERS TONIGHT THROUGH TUE NIGHT.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 303 PM CDT SUN AUG 19 2012
FOR WEDNESDAY THROUGH THURSDAY NIGHT...MODELS SHOW A BROAD UPPER
LEVEL RIDGE OVER THE REGION WITH HIGH PRESSURE AT THE SURFACE. THIS
WILL KEEP CONDITIONS DRY ACROSS THE PAH FORECAST AREA. SOUTHERLY
FLOW AND PLENTY OF SUNSHINE WILL KEEP TEMPERATURES NEAR NORMAL WITH
HIGHS IN THE UPPER 80S AND LOWS IN THE LOWER TO MIDDLE 60S.
MODELS DIVERGE ON FRIDAY. THE 00Z ECMWF SHOWED AN UPPER LEVEL LOW
SLIDING INTO THE AREA...BRINGING SOME QPF TO MAINLY SOUTHERN
PORTIONS OF THE PAH FORECAST AREA. THE 12Z ECMWF IS MUCH LESS
PRONOUNCED WITH THIS FEATURE AND KEEPS ANY PRECIP JUST WEST OF OUR
AREA. THE LATEST GFS...ON THE OTHER HAND...BRINGS A SURFACE LOW OUT
OF THE PLAINS AND BRINGS CHANCES OF PRECIP INTO OUR WESTERN COUNTIES
FRIDAY NIGHT AND THE ENTIRE PAH FA ON SATURDAY. MODELS LACK ANY
REAL CONSISTENCY...SO JUST STUCK WITH SLIGHT TO VERY LOW CHANCE
POPS FOR NOW...WITH SLIGHTLY HIGHER POPS ACROSS OUR SOUTHERN
COUNTIES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 946 PM CDT SUN AUG 19 2012
ADDED IFR LEVEL FOG TO THE KCGI TAF...AS SKIES WILL LIKELY CLEAR
AND WINDS WILL BE WEAK OVERNIGHT. WOULD NOT BE SURPRISED TO SEE
VLIFR CONDITIONS IN FOG AT KCGI. ELSEWHERE WOULD NOT EXPECT FOG
DEVELOPMENT UNLESS A SHOWER CLIPS KPAH IN THE NEXT HOUR TWO.
ISSUED AT 646 PM CDT SUN AUG 19 2012
A FEW SHOWERS AND POSSIBLY A THUNDERSTORM CONTINUE TO MOVE
SOUTHEAST ACROSS SOUTHEAST MISSOURI. HAD TO INSERT A VCSH AT KCGI
FOR A FEW HOURS THIS EVENING. THE SHOWERS SHOULD DISSIPATE AS THE
SUN SETS THIS EVENING.
ANOTHER IMPULSE MAY BRING A FEW SHOWERS TO THE AREA AGAIN MONDAY
AFTERNOON...BUT THEY WILL MAINLY BE OVER WEST KENTUCKY OR
SOUTHEAST OF THE TAF SITES. KOWB WOULD BE THE MOST LIKELY SITE TO
EXPERIENCE A BRIEF...BONAFIDE SHOWER.
IF SKIES CAN CLEAR SUBSTANTIALLY OVERNIGHT...SOME MVFR FOG WILL BE
POSSIBLE WITH NEARLY CALM WINDS AT KCGI. FOR NOW KEPT THE FORECAST
DRY...BUT IF A SHOWER DUMPS MUCH RAIN AT ALL THIS EVENING...MAY NEED
TO ADD IT IN LATER THIS EVENING.
&&
.FIRE WEATHER...
ISSUED AT 303 PM CDT SUN AUG 19 2012
VERY DRY AIR WILL REMAIN IN PLACE FOR THE FIRST HALF OF THE
UPCOMING WEEKS. IN FACT...SOME LOCATIONS MAY SEE RELATIVE
HUMIDITIES DIP TO NEAR 20 PERCENT BY TUESDAY. IN ADDITION...10
HOUR FUEL MOISTURES HAVE NOW FALLEN BACK INTO THE 6 TO 10 PERCENT
RANGE. THUS...THE RISK OF RAPID WILDFIRE GROWTH WILL BE ELEVATED
DURING THIS TIME FRAME. WINDS...BOTH AT THE SURFACE AND ALOFT...
SHOULD REMAIN GENERALLY LIGHT.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...MEFFERT
LONG TERM....RST
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
646 PM CDT SUN AUG 19 2012
.UPDATE...
ISSUED AT 646 PM CDT SUN AUG 19 2012
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 00Z TAF ISSUANCE.
UPDATE ISSUED AT 303 PM CDT SUN AUG 19 2012
SMALL CLUSTER OR TWO OF SHOWERS AND POSSIBLY A RUMBLE OR TWO OF
THUNDER HAVE DEVELOPED OUT OVER PORTIONS OF SE MO...ESP NORTH AND
WEST OF POPLAR BLUFF. THEREFORE...WILL UP POPS UP INTO THE SCT
RANGE FOR THE NEXT FEW HOURS.
UPDATE ISSUED AT 1104 AM CDT SUN AUG 19 2012
BASED UPON THE LATEST RADAR/STLT/NAM AND RUC PROGGED SOUNDINGS FOR
THE REST OF TODAY...AM INCLINED TO REDUCE SHOWER/STORM CHANCES
DOWN TO AROUND 10 PERCENT. EVEN THO WEAK IMPULSE ALOFT IS
APPROACHING IN CYCLONIC NW FLOW..THERE JUST SEEMS TO BE NO
INSTABILITY OR OVERALL MOISTURE TO WORK WITH /ESP BELOW 8000 FT/.
CANNOT RULE OUT AN ISOLD SHOWER OR SPRINKLE HERE AND THERE...BUT
CAPES PROGGED TO REMAIN LESS THAN 100 J/KG THIS AFTN...SO THUNDER
CHCS LOOK PRACTICALLY NIL.
ALSO...UPDATED THE AVIATION SECTION BELOW FOR THE UPCOMING 18Z
TAF FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 303 PM CDT SUN AUG 19 2012
BASED GENERALLY ON SAME REASONING AS IN THE UPDATE SECTION ABOVE...
AM INCLINED TO REDUCE SHOWER/STORM CHANCES DOWN TO AROUND 10
PERCENT FOR MONDAY/TUE ALSO. AGAIN...EVEN THO WEAK IMPULSES ALOFT
WILL CONTINUE TO ROTATE SSE WITHIN FAIRLY DEEP TROF /CYCLONIC FLOW/
OVER THE OHIO VALLEY...THERE JUST SEEMS TO BE VERY LITTLE
INSTABILITY AND OVERALL MOISTURE TO WORK WITH///ESP IN THE LOWEST
7000 TO 10000 FT. CANNOT RULE OUT AN ISOLD SHOWER OR SPRINKLES HERE
AND THERE...BUT CAPES PROGGED TO REMAIN LESS THAN 400 J/KG FOR THE
MOST PART THROUGH TUE...SO THUNDER CHCS CONTINUE TO LOOK PRACTICALLY
NIL.
AS FAR AS TEMPS ARE CONCERNED...WILL CONT TO IGNORE THE OBVIOUSLY
COLD MAV TEMP BIAS. EVEN THE MET MOS TEMPS SEEM TO BE RUNNING A
FEW DEGREES TOO COOL TODAY. HOWEVER...GIVEN THE FACT THAT THERE
MAY BE MORE IN THE WAY OF MID CLOUDS MONDAY...WILL STAY CLOSE TO
THE MET MOS NUMBERS TONIGHT THROUGH TUE NIGHT.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 303 PM CDT SUN AUG 19 2012
FOR WEDNESDAY THROUGH THURSDAY NIGHT...MODELS SHOW A BROAD UPPER
LEVEL RIDGE OVER THE REGION WITH HIGH PRESSURE AT THE SURFACE. THIS
WILL KEEP CONDITIONS DRY ACROSS THE PAH FORECAST AREA. SOUTHERLY
FLOW AND PLENTY OF SUNSHINE WILL KEEP TEMPERATURES NEAR NORMAL WITH
HIGHS IN THE UPPER 80S AND LOWS IN THE LOWER TO MIDDLE 60S.
MODELS DIVERGE ON FRIDAY. THE 00Z ECMWF SHOWED AN UPPER LEVEL LOW
SLIDING INTO THE AREA...BRINGING SOME QPF TO MAINLY SOUTHERN
PORTIONS OF THE PAH FORECAST AREA. THE 12Z ECMWF IS MUCH LESS
PRONOUNCED WITH THIS FEATURE AND KEEPS ANY PRECIP JUST WEST OF OUR
AREA. THE LATEST GFS...ON THE OTHER HAND...BRINGS A SURFACE LOW OUT
OF THE PLAINS AND BRINGS CHANCES OF PRECIP INTO OUR WESTERN COUNTIES
FRIDAY NIGHT AND THE ENTIRE PAH FA ON SATURDAY. MODELS LACK ANY
REAL CONSISTENCY...SO JUST STUCK WITH SLIGHT TO VERY LOW CHANCE
POPS FOR NOW...WITH SLIGHTLY HIGHER POPS ACROSS OUR SOUTHERN
COUNTIES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 646 PM CDT SUN AUG 19 2012
A FEW SHOWERS AND POSSIBLY A THUNDERSTORM CONTINUE TO MOVE
SOUTHEAST ACROSS SOUTHEAST MISSOURI. HAD TO INSERT A VCSH AT KCGI
FOR A FEW HOURS THIS EVENING. THE SHOWERS SHOULD DISSIPATE AS THE
SUN SETS THIS EVENING.
ANOTHER IMPULSE MAY BRING A FEW SHOWERS TO THE AREA AGAIN MONDAY
AFTERNOON...BUT THEY WILL MAINLY BE OVER WEST KENTUCKY OR
SOUTHEAST OF THE TAF SITES. KOWB WOULD BE THE MOST LIKELY SITE TO
EXPERIENCE A BRIEF...BONAFIDE SHOWER.
IF SKIES CAN CLEAR SUBSTANTIALLY OVERNIGHT...SOME MVFR FOG WILL BE
POSSIBLE WITH NEARLY CALM WINDS AT KCGI. FOR NOW KEPT THE FORECAST
DRY...BUT IF A SHOWER DUMPS MUCH RAIN AT ALL THIS EVENING...MAY NEED
TO ADD IT IN LATER THIS EVENING.
&&
.FIRE WEATHER...
ISSUED AT 303 PM CDT SUN AUG 19 2012
VERY DRY AIR WILL REMAIN IN PLACE FOR THE FIRST HALF OF THE
UPCOMING WEEKS. IN FACT...SOME LOCATIONS MAY SEE RELATIVE
HUMIDITIES DIP TO NEAR 20 PERCENT BY TUESDAY. IN ADDITION...10
HOUR FUEL MOISTURES HAVE NOW FALLEN BACK INTO THE 6 TO 10 PERCENT
RANGE. THUS...THE RISK OF RAPID WILDFIRE GROWTH WILL BE ELEVATED
DURING THIS TIME FRAME. WINDS...BOTH AT THE SURFACE AND ALOFT...
SHOULD REMAIN GENERALLY LIGHT.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...MEFFERT
LONG TERM....RST
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
131 PM EDT SAT AUG 18 2012
.SYNOPSIS...
A COLD FRONT WILL STALL ALONG THE MAINE COAST TODAY AND TONIGHT.
LOW PRESSURE WILL APPROACH FROM THE SOUTH LATER SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...CONTINUE TO TRIM BACK ON POPS/WX OVER DOWNEAST MAINE.
WHILE THE SHOWERS HAVE DISSIPATED OR MOVED OUT OF THE
AREA...ENOUGH INSTABILITY REMAINS OVER SOUTHEAST MAINE TO NOT RULE
OUT SCATTERED SHOWERS REDEVELOPING THIS AFTERNOON.
PREVIOUS DISCUSSION...
A COLD FRONT IS EXPECTED TO BECOME STATIONARY ALONG THE DOWNEAST
COAST TODAY. WITH UPPER LOW NEAR JAMES BAY AND 500MB FLOW PARALLEL
TO THE FRONT THIS SCENARIO LOOKS MOST REASONABLE. AT THE SAME TIME
SURFACE HIGH PRESSURE WILL BUILD IN FROM THE WEST LATER TODAY AND
TONIGHT. FOR POPS HAVE BEEN USING HRRR THEN MERGING IT WITH BLEND
OF THE NAM12...GFS40...SREF AND ECMWF. FOR QPF HAVE USED THE SAME
BLEND BUT WILL EXCHANGE NAM12 FOR NAM80. FOR WIND HAVE BLENDED
NAM12 AND GMOS AND WILL USE ONLY GMOS LATE TONIGHT. FOR
TEMPERATURE AND DEW POINT WILL USE GMOS WITH SOME MINOR
ADJUSTMENTS TO MAXIMUM TEMPERATURE.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
MAIN CHALLENGE WILL BE STALLED FRONTAL BOUNDARY ALONG THE COAST ON
SUNDAY AND WEAK LOW PRES WAVE MOVING UP ALONG THE FRONT.
DECIDED TO FOLLOW A BLEND OF THE ECMWF AND CANADIAN GLOBAL THIS
FCST CYCLE SHOWING AN AREA OF RAIN AFFECTING MAINLY THE COAST AND
OVER THE GULF OF MAINE WATERS FOR SUNDAY. THESE 2 NUMERICAL MODELS
WERE CONSISTENT W/THEIR PREVIOUS RUNS OF SHOWING THIS WAVE MOVING
UP ALONG THE FRONT. THE BOUNDARY WILL SERVE AS A CONVERGENCE AXIS
AND W/THE LOW, ENOUGH FORCING WILL BE THERE FOR A PERIOD OF RAIN
IN THE AFOREMENTIONED AREAS. THEREFORE, INCREASED THE RAIN PERCENTAGES
TO 50-60% ACROSS THE COAST AND OVER THE WATERS UP THROUGH 18Z AND
THEN DRY THINGS OUT AS THE FRONT SLIDES FURTHER SOUTH AND
EAST.THIS WILL ALSO HOLD DOWN TEMPERATURES OVER THE DOWNEAST AND
THE COAST(LOW/MID 70S). FURTHER NORTH AND WEST, DRIER CONDITIONS
AND HENCE WARMER TEMPERATURES(MID-UPPER 70S). QPF AMOUNTS WERE
ADJUSTED USING THE ECMWF AND CANADIAN GLOBAL W/AREAL ADJUSTMENTS.
THEREFORE, NOT EXPECTING MORE THAN .10" OF RAINFALL ALONG THE
IMMEDIATE COAST.
HIGH PRES IS SET TO RIDGE IN ACROSS THE CWA FROM THE SW SUNDAY
NIGHT INTO MONDAY. THIS SHOULD ALLOW FOR DRY CONDITIONS AND WARMER
TEMPERATURES. BROAD SWLY FLOW ALOFT WILL ALLOW FOR SOME CUMULUS TO
DEVELOP BY LATE MORNING. REMOVED THE MENTION OF RAIN SHOWERS FOR
MONDAY AND RAISED MAXES FROM THE PREVIOUS FORECAST UP A CATEGORY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
BACKED AWAY FROM GMOS THROUGH WEDNESDAY AND BASICALLY STAYED
CLOSER TO THE ECMWF. THE ECMWF HAS BEEN CONSISTENT W/THE SYNOPTIC
PATTERN OF A BROAD SW FLOW ALOFT W/CLOSED LOWER OVER HUDSON`S BAY.
THIS WILL ALLOW FOR A WAVE OF LOW PRES TO DEVELOP ON THAT STALLED
FRONTAL BOUNDARY JUST OFF THE MAINE COAST TO MOVE UP ALONG THE
FRONT ON TUESDAY. THE GFS APPEARED TO BE TOO STRONG AND AGGRESSIVE
W/THE LOW WHILE THE ECMWF AND CANADIAN GLOBAL KEEP THE LOW FURTHER
S AND E AND BOTH ARE NOT AS STRONG W/THE WAVE AND HAVE A SECOND
FRONT APPROACHING FROM CANADA BY TUESDAY AFTERNOON. DECIDED TO CUT
BACK ON PRECIP CHANCES TUESDAY W/THE LOW OFF THE COAST AND LEAN
W/A 20-30% CHANCE FOR SHOWERS IN THE AFTERNOON DUE TO THE COLD
FRONT MOVING IN FROM THE WEST. BOTH THE CANADIAN GLOBAL AND ECMWF
SUPPORT SOME SHOWER AS UPPER LEVEL SUPPORT IS THERE. TWEAKED
TEMPERATURES FOR TUESDAY TO BRING THEM UP A CATEGORY INTO THE
MID AND UPPER 70S. HIGH PRES AT THE SFC IS SHOWN TO MOVE ACROSS
THE REGION ON WEDNESDAY AND THE FRONT SLIDES TO THE EAST. THIS
WILL ALLOW FOR A DRY AND COMFORTABLE DAY. UPPER FLOW APPEARS TO
SHIFT A BIT TO A MORE WESTERLY COMPONENT ALLOWING FOR A DRIER SETUP.
OVERNIGHT TEMPERATURES MONDAY NIGHT AND AGAIN TUESDAY NIGHT LOOKED
TO NEED ADJUSTMENTS UPWARD USING A NAM12/GMOS BLEND. BROAD SW FLOW
ALOFT SEEMS TO FAVOR A WARM SCENARIO. DAY CREW CAN ASSESS THIS
FURTHER W/NEWER MODEL GUIDANCE.
THE UPPER TROF LOOKS LIKE IT WILL SHARPEN AGAIN BY LATE WEEK W/S
FRONTAL BOUNDARY APPROACHING. THERE IS THE POTENTIAL FOR SHOWERS
AND POSSIBLE TSTMS ON THURSDAY AND AGAIN FRIDAY AND THE FRONT WILL
BE SLOW TO MOVE ACROSS THE REGION. ATTM, STAYED CLOSER TO GMOS
W/30% POPS AND STAYED CLOSER TO THE TEMPERATURES SHOWING NEAR
NORMAL READINGS FOR LATE AUGUST.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
NEAR TERM: PREDOMINANTLY VFR CONDITIONS EXPECTED THROUGH TONIGHT.
SHORT TERM: POSSIBLE IFR/MVFR FOR THE COAST ON SUNDAY AND THEN
CONDITIONS IMPROVE TO VFR. IT LOOKS LIKE VFR FOR THE NORTHERN
TERMINALS THROUGH MONDAY. THERE DOES APPEAR TO BE SOME POTENTIAL
FOR MVFR AND POSSIBLY IFR CONDITIONS LATER MONDAY NIGHT INTO
TUESDAY MORNING W/A LIGHT ESE FLOW SETTING UP.
&&
.MARINE...
NEAR TERM: FOR WINDS HAVE USED A 50/50 BLEND OF THE NAM12 AND
GFS40 AND ADJUSTED BLEND DOWN 20 PERCENT DUE TO EXPECTED BOUNDARY
CONDITIONS. WILL USE NAM/SWAN TO INITIALIZE WAVE GRIDS. WILL
ADJUST WAVE MODEL DOWN 1 FOOT. PRIMARY WAVE GROUP IS WEAK
SOUTHERLY FETCH AROUND PERIPHERY OF HIGH OFF-SHORE. WAVE MODELS ARE
TOO HIGH WITH THIS WAVE GROUP. WNA SPECTRAL CONTINUES TO SHOW
BACKGROUND SOUTHEAST SWELL AT AROUND 1 FOOT. VERY LONG PERIOD
SWELL FROM ATLANTIC TROPICAL SYSTEMS MAY SHOW UP BUT NOT UNTIL
NEXT WEEK. WILL KEEP FOG ACROSS COASTAL WATERS WITH FRONT STALLED
ALONG COAST.
SHORT TERM: NO HEADLINES ANTICIPATED. A BLEND OF THE NAM12 AND
GFS40 WAS USED FOR THE WINDS INTO MONDAY WHICH SHOWS SUSTAINED
WINDS AT 10-15 KTS. AN ESE SWELL LOOKS POSSIBLE BY MONDAY AND
COULD CONTINUE THROUGH THE WEEK W/A LONG PERIOD. AS MENTIONED
IN THE NEAR TERM, WANAVE RUNNING TOO HIGH AND THEREFORE STAYED
W/THE CURRENT WAVE HEIGHTS OF 2-3 FT THROUGH THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MIGNONE/RUNYAN
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...MIGNONE/RUNYAN
MARINE...MIGNONE/RUNYAN/HEWITT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1011 AM EDT SAT AUG 18 2012
.SYNOPSIS...
A COLD FRONT WILL STALL ALONG THE MAINE COAST TODAY AND TONIGHT.
LOW PRESSURE WILL APPROACH FROM THE SOUTH LATER SUNDAY AND MONDAY.&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...HAVE ADJUSTED POP AND WEATHER GRIDS TO BETTER FIT CURRENT
RADAR IMAGERY.
A COLD FRONT IS EXPECTED TO BECOME STATIONARY ALONG THE DOWNEAST
COAST TODAY. WITH UPPER LOW NEAR JAMES BAY AND 500MB FLOW PARALLEL
TO THE FRONT THIS SCENARIO LOOKS MOST REASONABLE. AT THE SAME TIME
SURFACE HIGH PRESSURE WILL BUILD IN FROM THE WEST LATER TODAY AND
TONIGHT. FOR POPS HAVE BEEN USING HRRR THEN MERGING IT WITH BLEND
OF THE NAM12...GFS40...SREF AND ECMWF. FOR QPF HAVE USED THE SAME
BLEND BUT WILL EXCHANGE NAM12 FOR NAM80. FOR WIND HAVE BLENDED
NAM12 AND GMOS AND WILL USE ONLY GMOS LATE TONIGHT. FOR
TEMPERATURE AND DEW POINT WILL USE GMOS WITH SOME MINOR
ADJUSTMENTS TO MAXIMUM TEMPERATURE.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
MAIN CHALLENGE WILL BE STALLED FRONTAL BOUNDARY ALONG THE COAST ON
SUNDAY AND WEAK LOW PRES WAVE MOVING UP ALONG THE FRONT.
DECIDED TO FOLLOW A BLEND OF THE ECMWF AND CANADIAN GLOBAL THIS
FCST CYCLE SHOWING AN AREA OF RAIN AFFECTING MAINLY THE COAST AND
OVER THE GULF OF MAINE WATERS FOR SUNDAY. THESE 2 NUMERICAL MODELS
WERE CONSISTENT W/THEIR PREVIOUS RUNS OF SHOWING THIS WAVE MOVING
UP ALONG THE FRONT. THE BOUNDARY WILL SERVE AS A CONVERGENCE AXIS
AND W/THE LOW, ENOUGH FORCING WILL BE THERE FOR A PERIOD OF RAIN
IN THE AFOREMENTIONED AREAS. THEREFORE, INCREASED THE RAIN PERCENTAGES
TO 50-60% ACROSS THE COAST AND OVER THE WATERS UP THROUGH 18Z AND
THEN DRY THINGS OUT AS THE FRONT SLIDES FURTHER SOUTH AND
EAST.THIS WILL ALSO HOLD DOWN TEMPERATURES OVER THE DOWNEAST AND
THE COAST(LOW/MID 70S). FURTHER NORTH AND WEST, DRIER CONDITIONS
AND HENCE WARMER TEMPERATURES(MID-UPPER 70S). QPF AMOUNTS WERE
ADJUSTED USING THE ECMWF AND CANADIAN GLOBAL W/AREAL ADJUSTMENTS.
THEREFORE, NOT EXPECTING MORE THAN .10" OF RAINFALL ALONG THE
IMMEDIATE COAST.
HIGH PRES IS SET TO RIDGE IN ACROSS THE CWA FROM THE SW SUNDAY
NIGHT INTO MONDAY. THIS SHOULD ALLOW FOR DRY CONDITIONS AND WARMER
TEMPERATURES. BROAD SWLY FLOW ALOFT WILL ALLOW FOR SOME CUMULUS TO
DEVELOP BY LATE MORNING. REMOVED THE MENTION OF RAIN SHOWERS FOR
MONDAY AND RAISED MAXES FROM THE PREVIOUS FORECAST UP A CATEGORY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
BACKED AWAY FROM GMOS THROUGH WEDNESDAY AND BASICALLY STAYED
CLOSER TO THE ECMWF. THE ECMWF HAS BEEN CONSISTENT W/THE SYNOPTIC
PATTERN OF A BROAD SW FLOW ALOFT W/CLOSED LOWER OVER HUDSON`S BAY.
THIS WILL ALLOW FOR A WAVE OF LOW PRES TO DEVELOP ON THAT STALLED
FRONTAL BOUNDARY JUST OFF THE MAINE COAST TO MOVE UP ALONG THE
FRONT ON TUESDAY. THE GFS APPEARED TO BE TOO STRONG AND AGGRESSIVE
W/THE LOW WHILE THE ECMWF AND CANADIAN GLOBAL KEEP THE LOW FURTHER
S AND E AND BOTH ARE NOT AS STRONG W/THE WAVE AND HAVE A SECOND
FRONT APPROACHING FROM CANADA BY TUESDAY AFTERNOON. DECIDED TO CUT
BACK ON PRECIP CHANCES TUESDAY W/THE LOW OFF THE COAST AND LEAN
W/A 20-30% CHANCE FOR SHOWERS IN THE AFTERNOON DUE TO THE COLD
FRONT MOVING IN FROM THE WEST. BOTH THE CANADIAN GLOBAL AND ECMWF
SUPPORT SOME SHOWER AS UPPER LEVEL SUPPORT IS THERE. TWEAKED
TEMPERATURES FOR TUESDAY TO BRING THEM UP A CATEGORY INTO THE
MID AND UPPER 70S. HIGH PRES AT THE SFC IS SHOWN TO MOVE ACROSS
THE REGION ON WEDNESDAY AND THE FRONT SLIDES TO THE EAST. THIS
WILL ALLOW FOR A DRY AND COMFORTABLE DAY. UPPER FLOW APPEARS TO
SHIFT A BIT TO A MORE WESTERLY COMPONENT ALLOWING FOR A DRIER SETUP.
OVERNIGHT TEMPERATURES MONDAY NIGHT AND AGAIN TUESDAY NIGHT LOOKED
TO NEED ADJUSTMENTS UPWARD USING A NAM12/GMOS BLEND. BROAD SW FLOW
ALOFT SEEMS TO FAVOR A WARM SCENARIO. DAY CREW CAN ASSESS THIS
FURTHER W/NEWER MODEL GUIDANCE.
THE UPPER TROF LOOKS LIKE IT WILL SHARPEN AGAIN BY LATE WEEK W/S
FRONTAL BOUNDARY APPROACHING. THERE IS THE POTENTIAL FOR SHOWERS
AND POSSIBLE TSTMS ON THURSDAY AND AGAIN FRIDAY AND THE FRONT WILL
BE SLOW TO MOVE ACROSS THE REGION. ATTM, STAYED CLOSER TO GMOS
W/30% POPS AND STAYED CLOSER TO THE TEMPERATURES SHOWING NEAR
NORMAL READINGS FOR LATE AUGUST.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: EXPECT VFR CONDITIONS TODAY WITH IFR CONDITIONS LATER
TONIGHT MOSTLY DUE TO CEILINGS.
SHORT TERM: POSSIBLE IFR/MVFR FOR THE COAST ON SUNDAY AND THEN
CONDITIONS IMPROVE TO VFR. IT LOOKS LIKE VFR FOR THE NORTHERN
TERMINALS THROUGH MONDAY. THERE DOES APPEAR TO BE SOME POTENTIAL
FOR MVFR AND POSSIBLY IFR CONDITIONS LATER MONDAY NIGHT INTO
TUESDAY MORNING W/A LIGHT ESE FLOW SETTING UP.
&&
.MARINE...
NEAR TERM: FOR WINDS HAVE USED A 50/50 BLEND OF THE NAM12 AND
GFS40 AND ADJUSTED BLEND DOWN 20 PERCENT DUE TO EXPECTED BOUNDARY
CONDITIONS. WILL USE NAM/SWAN TO INITIALIZE WAVE GRIDS. WILL
ADJUST WAVE MODEL DOWN 1 FOOT. PRIMARY WAVE GROUP IS WEAK
SOUTHERLY FETCH AROUND PERIPHERY OF HIGH OFF-SHORE. WAVE MODELS ARE
TOO HIGH WITH THIS WAVE GROUP. WNA SPECTRAL CONTINUES TO SHOW
BACKGROUND SOUTHEAST SWELL AT AROUND 1 FOOT. VERY LONG PERIOD
SWELL FROM ATLANTIC TROPICAL SYSTEMS MAY SHOW UP BUT NOT UNTIL
NEXT WEEK. WILL KEEP FOG ACROSS COASTAL WATERS WITH FRONT STALLED
ALONG COAST.
SHORT TERM: NO HEADLINES ANTICIPATED. A BLEND OF THE NAM12 AND
GFS40 WAS USED FOR THE WINDS INTO MONDAY WHICH SHOWS SUSTAINED
WINDS AT 10-15 KTS. AN ESE SWELL LOOKS POSSIBLE BY MONDAY AND
COULD CONTINUE THROUGH THE WEEK W/A LONG PERIOD. AS MENTIONED
IN THE NEAR TERM, WANAVE RUNNING TOO HIGH AND THEREFORE STAYED
W/THE CURRENT WAVE HEIGHTS OF 2-3 FT THROUGH THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MIGNONE/RUNYAN
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...MIGNONE/RUNYAN
MARINE...MIGNONE/RUNYAN/HEWITT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
713 AM EDT SAT AUG 18 2012
.SYNOPSIS...
A COLD FRONT WILL STALL ALONG THE MAINE COAST TODAY AND TONIGHT.
LOW PRESSURE WILL APPROACH FROM THE SOUTH LATER SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...HAVE ADJUSTED POP AND WEATHER GRIDS TO BETTER FIT CURRENT
RADAR. HAVE ALSO ADJUSTED FOG AREAS IN COASTAL ZONES.
A COLD FRONT IS EXPECTED TO BECOME STATIONARY ALONG THE DOWNEAST
COAST TODAY. WITH UPPER LOW NEAR JAMES BAY AND 500MB FLOW PARALLEL
TO THE FRONT THIS SCENARIO LOOKS MOST REASONABLE. AT THE SAME TIME
SURFACE HIGH PRESSURE WILL BUILD IN FROM THE WEST LATER TODAY AND
TONIGHT. FOR POPS HAVE BEEN USING HRRR THEN MERGING IT WITH BLEND
OF THE NAM12...GFS40...SREF AND ECMWF. FOR QPF HAVE USED THE SAME
BLEND BUT WILL EXCHANGE NAM12 FOR NAM80. FOR WIND HAVE BLENDED
NAM12 AND GMOS AND WILL USE ONLY GMOS LATE TONIGHT. FOR
TEMPERATURE AND DEW POINT WILL USE GMOS WITH SOME MINOR
ADJUSTMENTS TO MAXIMUM TEMPERATURE.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
MAIN CHALLENGE WILL BE STALLED FRONTAL BOUNDARY ALONG THE COAST ON
SUNDAY AND WEAK LOW PRES WAVE MOVING UP ALONG THE FRONT.
DECIDED TO FOLLOW A BLEND OF THE ECMWF AND CANADIAN GLOBAL THIS
FCST CYCLE SHOWING AN AREA OF RAIN AFFECTING MAINLY THE COAST AND
OVER THE GULF OF MAINE WATERS FOR SUNDAY. THESE 2 NUMERICAL MODELS
WERE CONSISTENT W/THEIR PREVIOUS RUNS OF SHOWING THIS WAVE MOVING
UP ALONG THE FRONT. THE BOUNDARY WILL SERVE AS A CONVERGENCE AXIS
AND W/THE LOW, ENOUGH FORCING WILL BE THERE FOR A PERIOD OF RAIN
IN THE AFOREMENTIONED AREAS. THEREFORE, INCREASED THE RAIN PERCENTAGES
TO 50-60% ACROSS THE COAST AND OVER THE WATERS UP THROUGH 18Z AND
THEN DRY THINGS OUT AS THE FRONT SLIDES FURTHER SOUTH AND
EAST.THIS WILL ALSO HOLD DOWN TEMPERATURES OVER THE DOWNEAST AND
THE COAST(LOW/MID 70S). FURTHER NORTH AND WEST, DRIER CONDITIONS
AND HENCE WARMER TEMPERATURES(MID-UPPER 70S). QPF AMOUNTS WERE
ADJUSTED USING THE ECMWF AND CANADIAN GLOBAL W/AREAL ADJUSTMENTS.
THEREFORE, NOT EXPECTING MORE THAN .10" OF RAINFALL ALONG THE
IMMEDIATE COAST.
HIGH PRES IS SET TO RIDGE IN ACROSS THE CWA FROM THE SW SUNDAY
NIGHT INTO MONDAY. THIS SHOULD ALLOW FOR DRY CONDITIONS AND WARMER
TEMPERATURES. BROAD SWLY FLOW ALOFT WILL ALLOW FOR SOME CUMULUS TO
DEVELOP BY LATE MORNING. REMOVED THE MENTION OF RAIN SHOWERS FOR
MONDAY AND RAISED MAXES FROM THE PREVIOUS FORECAST UP A CATEGORY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
BACKED AWAY FROM GMOS THROUGH WEDNESDAY AND BASICALLY STAYED
CLOSER TO THE ECMWF. THE ECMWF HAS BEEN CONSISTENT W/THE SYNOPTIC
PATTERN OF A BROAD SW FLOW ALOFT W/CLOSED LOWER OVER HUDSON`S BAY.
THIS WILL ALLOW FOR A WAVE OF LOW PRES TO DEVELOP ON THAT STALLED
FRONTAL BOUNDARY JUST OFF THE MAINE COAST TO MOVE UP ALONG THE
FRONT ON TUESDAY. THE GFS APPEARED TO BE TOO STRONG AND AGGRESSIVE
W/THE LOW WHILE THE ECMWF AND CANADIAN GLOBAL KEEP THE LOW FURTHER
S AND E AND BOTH ARE NOT AS STRONG W/THE WAVE AND HAVE A SECOND
FRONT APPROACHING FROM CANADA BY TUESDAY AFTERNOON. DECIDED TO CUT
BACK ON PRECIP CHANCES TUESDAY W/THE LOW OFF THE COAST AND LEAN
W/A 20-30% CHANCE FOR SHOWERS IN THE AFTERNOON DUE TO THE COLD
FRONT MOVING IN FROM THE WEST. BOTH THE CANADIAN GLOBAL AND ECMWF
SUPPORT SOME SHOWER AS UPPER LEVEL SUPPORT IS THERE. TWEAKED
TEMPERATURES FOR TUESDAY TO BRING THEM UP A CATEGORY INTO THE
MID AND UPPER 70S. HIGH PRES AT THE SFC IS SHOWN TO MOVE ACROSS
THE REGION ON WEDNESDAY AND THE FRONT SLIDES TO THE EAST. THIS
WILL ALLOW FOR A DRY AND COMFORTABLE DAY. UPPER FLOW APPEARS TO
SHIFT A BIT TO A MORE WESTERLY COMPONENT ALLOWING FOR A DRIER SETUP.
OVERNIGHT TEMPERATURES MONDAY NIGHT AND AGAIN TUESDAY NIGHT LOOKED
TO NEED ADJUSTMENTS UPWARD USING A NAM12/GMOS BLEND. BROAD SW FLOW
ALOFT SEEMS TO FAVOR A WARM SCENARIO. DAYCREW CAN ASSESS THIS
FURTHER W/NEWER MODEL GUIDANCE.
THE UPPER TROF LOOKS LIKE IT WILL SHARPEN AGAIN BY LATE WEEK W/S
FRONTAL BOUNDARY APPROACHING. THERE IS THE POTENTIAL FOR SHOWERS
AND POSSIBLE TSTMS ON THURSDAY AND AGAIN FRIDAY AND THE FRONT WILL
BE SLOW TO MOVE ACROSS THE REGION. ATTM, STAYED CLOSER TO GMOS
W/30% POPS AND STAYED CLOSER TO THE TEMPERATURES SHOWING NEAR
NORMAL READINGS FOR LATE AUGUST.
&&
.AVIATION /11Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: EXPECT VFR CONDITIONS TODAY WITH IFR CONDITIONS LATER
TONIGHT MOSTLY DUE TO CEILINGS.
SHORT TERM: POSSIBLE IFR/MVFR FOR THE COAST ON SUNDAY AND THEN
CONDITIONS IMPROVE TO VFR. IT LOOKS LIKE VFR FOR THE NORTHERN
TERMINALS THROUGH MONDAY. THERE DOES APPEAR TO BE SOME POTENTIAL
FOR MVFR AND POSSIBLY IFR CONDITIONS LATER MONDAY NIGHT INTO
TUESDAY MORNING W/A LIGHT ESE FLOW SETTING UP.
&&
.MARINE...
NEAR TERM: FOR WINDS HAVE USED A 50/50 BLEND OF THE NAM12 AND
GFS40 AND ADJUSTED BLEND DOWN 20 PERCENT DUE TO EXPECTED BOUNDARY
CONDITIONS. WILL USE NAM/SWAN TO INITIALIZE WAVE GRIDS. WILL
ADJUST WAVE MODEL DOWN 1 FOOT. PRIMARY WAVE GROUP IS WEAK
SOUTHERLY FETCH AROUND PERIPHERY OF HIGH OFF-SHORE. WAVE MODELS ARE
TOO HIGH WITH THIS WAVE GROUP. WNA SPECTRAL CONTINUES TO SHOW
BACKGROUND SOUTHEAST SWELL AT AROUND 1 FOOT. VERY LONG PERIOD
SWELL FROM ATLANTIC TROPICAL SYSTEMS MAY SHOW UP BUT NOT UNTIL
NEXT WEEK. WILL KEEP FOG ACROSS COASTAL WATERS WITH FRONT STALLED
ALONG COAST.
SHORT TERM: NO HEADLINES ANTICIPATED. A BLEND OF THE NAM12 AND
GFS40 WAS USED FOR THE WINDS INTO MONDAY WHICH SHOWS SUSTAINED
WINDS AT 10-15 KTS. AN ESE SWELL LOOKS POSSIBLE BY MONDAY AND
COULD CONTINUE THROUGH THE WEEK W/A LONG PERIOD. AS MENTIONED
IN THE NEAR TERM, WANAVE RUNNING TOO HIGH AND THEREFORE STAYED
W/THE CURRENT WAVE HEIGHTS OF 2-3 FT THROUGH THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MIGNONE
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...MIGNONE
MARINE...MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
418 AM EDT SAT AUG 18 2012
.SYNOPSIS...
A COLD FRONT WILL STALL ALONG THE MAINE COAST TODAY AND TONIGHT.
LOW PRESSURE WILL APPROACH FROM THE SOUTH LATER SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
A COLD FRONT IS EXPECTED TO BECOME STATIONARY ALONG THE DOWNEAST
COAST TODAY. WITH UPPER LOW NEAR JAMES BAY AND 500MB FLOW PARALLEL
TO THE FRONT THIS SCENARIO LOOKS MOST REASONABLE. AT THE SAME TIME
SURFACE HIGH PRESSURE WILL BUILD IN FROM THE WEST LATER TODAY AND
TONIGHT. FOR POPS HAVE BEEN USING HRRR THEN MERGING IT WITH BLEND
OF THE NAM12...GFS40...SREF AND ECMWF. FOR QPF HAVE USED THE SAME
BLEND BUT WILL EXCHANGE NAM12 FOR NAM80. FOR WIND HAVE BLENDED
NAM12 AND GMOS AND WILL USE ONLY GMOS LATE TONIGHT. FOR
TEMPERATURE AND DEW POINT WILL USE GMOS WITH SOME MINOR
ADJUSTMENTS TO MAXIMUM TEMPERATURE.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
MAIN CHALLENGE WILL BE STALLED FRONTAL BOUNDARY ALONG THE COAST ON
SUNDAY AND WEAK LOW PRES WAVE MOVING UP ALONG THE FRONT.
DECIDED TO FOLLOW A BLEND OF THE ECMWF AND CANADIAN GLOBAL THIS
FCST CYCLE SHOWING AN AREA OF RAIN AFFECTING MAINLY THE COAST AND
OVER THE GULF OF MAINE WATERS FOR SUNDAY. THESE 2 NUMERICAL MODELS
WERE CONSISTENT W/THEIR PREVIOUS RUNS OF SHOWING THIS WAVE MOVING
UP ALONG THE FRONT. THE BOUNDARY WILL SERVE AS A CONVERGENCE AXIS
AND W/THE LOW, ENOUGH FORCING WILL BE THERE FOR A PERIOD OF RAIN
IN THE AFOREMENTIONED AREAS. THEREFORE, INCREASED THE RAIN PERCENTAGES
TO 50-60% ACROSS THE COAST AND OVER THE WATERS UP THROUGH 18Z AND
THEN DRY THINGS OUT AS THE FRONT SLIDES FURTHER SOUTH AND
EAST.THIS WILL ALSO HOLD DOWN TEMPERATURES OVER THE DOWNEAST AND
THE COAST(LOW/MID 70S). FURTHER NORTH AND WEST, DRIER CONDITIONS
AND HENCE WARMER TEMPERATURES(MID-UPPER 70S). QPF AMOUNTS WERE
ADJUSTED USING THE ECMWF AND CANADIAN GLOBAL W/AREAL ADJUSTMENTS.
THEREFORE, NOT EXPECTING MORE THAN .10" OF RAINFALL ALONG THE
IMMEDIATE COAST.
HIGH PRES IS SET TO RIDGE IN ACROSS THE CWA FROM THE SW SUNDAY
NIGHT INTO MONDAY. THIS SHOULD ALLOW FOR DRY CONDITIONS AND WARMER
TEMPERATURES. BROAD SWLY FLOW ALOFT WILL ALLOW FOR SOME CUMULUS TO
DEVELOP BY LATE MORNING. REMOVED THE MENTION OF RAIN SHOWERS FOR
MONDAY AND RAISED MAXES FROM THE PREVIOUS FORECAST UP A CATEGORY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
BACKED AWAY FROM GMOS THROUGH WEDNESDAY AND BASICALLY STAYED
CLOSER TO THE ECMWF. THE ECMWF HAS BEEN CONSISTENT W/THE SYNOPTIC
PATTERN OF A BROAD SW FLOW ALOFT W/CLOSED LOWER OVER HUDSON`S BAY.
THIS WILL ALLOW FOR A WAVE OF LOW PRES TO DEVELOP ON THAT STALLED
FRONTAL BOUNDARY JUST OFF THE MAINE COAST TO MOVE UP ALONG THE
FRONT ON TUESDAY. THE GFS APPEARED TO BE TOO STRONG AND AGGRESSIVE
W/THE LOW WHILE THE ECMWF AND CANADIAN GLOBAL KEEP THE LOW FURTHER
S AND E AND BOTH ARE NOT AS STRONG W/THE WAVE AND HAVE A SECOND
FRONT APPROACHING FROM CANADA BY TUESDAY AFTERNOON. DECIDED TO CUT
BACK ON PRECIP CHANCES TUESDAY W/THE LOW OFF THE COAST AND LEAN
W/A 20-30% CHANCE FOR SHOWERS IN THE AFTERNOON DUE TO THE COLD
FRONT MOVING IN FROM THE WEST. BOTH THE CANADIAN GLOBAL AND ECMWF
SUPPORT SOME SHOWER AS UPPER LEVEL SUPPORT IS THERE. TWEAKED
TEMPERATURES FOR TUESDAY TO BRING THEM UP A CATEGORY INTO THE
MID AND UPPER 70S. HIGH PRES AT THE SFC IS SHOWN TO MOVE ACROSS
THE REGION ON WEDNESDAY AND THE FRONT SLIDES TO THE EAST. THIS
WILL ALLOW FOR A DRY AND COMFORTABLE DAY. UPPER FLOW APPEARS TO
SHIFT A BIT TO A MORE WESTERLY COMPONENT ALLOWING FOR A DRIER SETUP.
OVERNIGHT TEMPERATURES MONDAY NIGHT AND AGAIN TUESDAY NIGHT LOOKED
TO NEED ADJUSTMENTS UPWARD USING A NAM12/GMOS BLEND. BROAD SW FLOW
ALOFT SEEMS TO FAVOR A WARM SCENARIO. DAYCREW CAN ASSESS THIS
FURTHER W/NEWER MODEL GUIDANCE.
THE UPPER TROF LOOKS LIKE IT WILL SHARPEN AGAIN BY LATE WEEK W/S
FRONTAL BOUNDARY APPROACHING. THERE IS THE POTENTIAL FOR SHOWERS
AND POSSIBLE TSTMS ON THURSDAY AND AGAIN FRIDAY AND THE FRONT WILL
BE SLOW TO MOVE ACROSS THE REGION. ATTM, STAYED CLOSER TO GMOS
W/30% POPS AND STAYED CLOSER TO THE TEMPERATURES SHOWING NEAR
NORMAL READINGS FOR LATE AUGUST.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: EXPECT VFR CONDITIONS TODAY WITH IFR CONDITIONS LATER
TONIGHT MOSTLY DUE TO CEILINGS.
SHORT TERM: POSSIBLE IFR/MVFR FOR THE COAST ON SUNDAY AND THEN
CONDITIONS IMPROVE TO VFR. IT LOOKS LIKE VFR FOR THE NORTHERN
TERMINALS THROUGH MONDAY. THERE DOES APPEAR TO BE SOME POTENTIAL
FOR MVFR AND POSSIBLY IFR CONDITIONS LATER MONDAY NIGHT INTO
TUESDAY MORNING W/A LIGHT ESE FLOW SETTING UP.
&&
.MARINE...
NEAR TERM: FOR WINDS HAVE USED A 50/50 BLEND OF THE NAM12 AND
GFS40 AND ADJUSTED BLEND DOWN 20 PERCENT DUE TO EXPECTED BOUNDARY
CONDITIONS. WILL USE NAM/SWAN TO INITIALIZE WAVE GRIDS. WILL
ADJUST WAVE MODEL DOWN 1 FOOT. PRIMARY WAVE GROUP IS WEAK
SOUTHERLY FETCH AROUND PERIPHERY OF HIGH OFF-SHORE. WAVE MODELS ARE
TOO HIGH WITH THIS WAVE GROUP. WNA SPECTRAL CONTINUES TO SHOW
BACKGROUND SOUTHEAST SWELL AT AROUND 1 FOOT. VERY LONG PERIOD
SWELL FROM ATLANTIC TROPICAL SYSTEMS MAY SHOW UP BUT NOT UNTIL
NEXT WEEK. WILL KEEP FOG ACROSS COASTAL WATERS WITH FRONT STALLED
ALONG COAST.
SHORT TERM: NO HEADLINES ANTICIPATED. A BLEND OF THE NAM12 AND
GFS40 WAS USED FOR THE WINDS INTO MONDAY WHICH SHOWS SUSTAINED
WINDS AT 10-15 KTS. AN ESE SWELL LOOKS POSSIBLE BY MONDAY AND
COULD CONTINUE THROUGH THE WEEK W/A LONG PERIOD. AS MENTIONED
IN THE NEAR TERM, WANAVE RUNNING TOO HIGH AND THEREFORE STAYED
W/THE CURRENT WAVE HEIGHTS OF 2-3 FT THROUGH THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MIGNONE
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...MIGNONE
MARINE...MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
932 PM EDT SUN AUG 19 2012
.SYNOPSIS...
A SERIES OF WEAK UPPER LEVEL LOW PRESSURE DISTURBANCES WILL CROSS
THE UPPER OHIO VALLEY EARLY THIS WEEK AND GENERATE A FEW SHOWERS
AND POSSIBLY THUNDERSTORMS. HIGH PRESSURE WILL MOVE INTO THE AREA
ON WEDNESDAY, RETURNING DRY WEATHER FOR THE MID-WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
RAIN SHOWERS ARE PERSISTING IN EAST CENTRAL OHIO AND WILL PUSH
SLOWLY EAST UNDER THE INFLUENCE OF AN UPPER LEVEL SHORT WAVE.
AN ISOLATED THUNDERSTORM IS POSSIBLE WITH THE SHOWERS. THE
SHOWERS WILL WEAKEN INTO THE EARLY MORNING BUT A CHANCE OF
SHOWERS WILL CONTINUE INTO THE EARLY MORNING AS THE SHORT
WAVE MOVES SLOWLY EAST. OVERNIGHT TEMPS ARE CLOSER TO THE COOLER
MAV GUIDANCE WITH LOWS RANGING FROM THE LOW TO MID 50S ACROSS MUCH
OF THE AREA.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
THERE IS ECMWF/GFS/NAM AGREEMENT THAT THE BROAD MID-LEVEL TROUGH
WILL REMAIN ACROSS THE OHIO VALLEY ON MONDAY AND AMPLIFY AS ITS
AXIS SWINGS INTO THE UPPER OHIO VALLEY LATE TUESDAY INTO
WEDNESDAY. WITH THE UPPER OHIO VALLEY IN A SOUTHWESTERLY FLOW
AHEAD OF THIS FEATURE AND THE MAJORITY OF MODEL SOLUTIONS SHOWING
WEAK INSTABILITY EACH DAY, CHC POPS WITH SCHC THUNDER IS FORECAST
FOR MONDAY WITH SCHC POPS/THUNDER ON TUESDAY. TEMPS WILL BE AROUND
5 DEGREES BELOW NORMAL THROUGH THIS PERIOD.
A MODEL CONSENSUS INDICATES THE TROUGH SLIDING EAST OF AREA AND
HIGH PRESSURE BUILDING IN FROM THE WEST ON WEDNESDAY. THIS WILL
ALLOW FOR A DRY FORECAST WITH MORE ABUNDANT SUNSHINE ON WEDNESDAY.
WITH INCREASED SUNSHINE TEMPS WILL WARM CLOSER TO SEASONAL NORMALS
ACROSS THE AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
CONSENSUS OF RECENT ECMWF AND NAEFS MODEL OUTPUT CONTINUES TO SHOW
BROAD HIGH PRESSURE UNDER WEAK FLOW ALOFT ACROSS THE EASTERN U.S.
INTO THE WEEKEND. HENCE, WILL MAINTAIN A FORECAST OF DRY AND
RELATIVELY CLOUD FREE CONDITIONS THROUGH THE PERIOD.
THIS SHOULD TRANSLATE TO EACH DAY HAVING A LARGER THAN NORMAL
DIURNAL TEMPERATURE RANGE. CONCUR WITH HPC THINKING, WITH SUPPORT
FROM GFS AND ECMWF MOS AND NAEFS MEDIAN VALUES, THAT LOWS THURSDAY
AND FRIDAY CAN BE UP TO 5 DEGREES COOLER THAN NORMAL, WHILE HIGHS BE
NEAR NORMAL. WITH POTENTIAL OF SURFACE DEW POINTS CLIMBING TO NEAR
NORMAL VALUES THIS WEEKEND, EXPECT WEEKEND LOWS TO LIKEWISE BE NEAR
NORMAL, WHILE HIGHS BE UP TO 5 DEGREES WARMER THAN NORMAL.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
EXPECT MAINLY VFR ACROSS THE UPPER OHIO VALLEY THROUGH 07Z.
PER BLEND OF RECENT RADAR DATA AND HRRR MODEL OUTPUT FORESEE ONLY
POTENTIAL OF RESTRICTIONS WOULD BE WITH ISOLATED SHOWERS AND
THUNDERSTORMS EARLY THIS EVENING.
LATEST GFS LAMP AND NAM MOS GUIDANCE FOR MOST TAF LOCATIONS
CONTINUES TO SHOW IFR RESTRICTIONS IN FOG 07Z-13Z. HOWEVER, AT
THIS JUNCTURE HAD ONLY ENOUGH CONFIDENCE TO INCLUDE MVFR
VISIBILITIES FOR MOST TAF SITES LATE TONIGHT...WITH A PERIOD OF
IFR AT KFKL AND KDUJ.
THE OTHER KEY TO FOG DEVELOPMENT LATE TONIGHT WOULD BE THE
LOCATION AND EXTENT OF SHOWERS EARLY TONIGHT AND THEIR SUBSEQUENT
EFFECT ON MOISTENING A SHALLOW TEMPERATURE-INVERSION CAPPED
SURFACE LAYER TONIGHT.
EXPECT THE REST OF MONDAY TO BE MAINLY VFR, ALTHOUGH AGAIN CANNOT
COMPLETELY RULE OUT THE POTENTIAL OF A BRIEF RESTRICTION WITH
ISOLATED AFTERNOON THUNDERSTORMS.
.OUTLOOK/ MONDAY NIGHT THROUGH FRIDAY/...
GENERALLY VFR CONDITIONS ARE EXPECTED. RESTRICTIONS MAY ACCOMPANY
SCATTERED THUNDERSTORMS MONDAY EVENING, AND PATCHY RIVER VALLEY
FOG EACH MORNING.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
813 PM EDT SUN AUG 19 2012
.SYNOPSIS...
A SERIES OF WEAK UPPER LEVEL LOW PRESSURE DISTURBANCES WILL CROSS
THE UPPER OHIO VALLEY EARLY THIS WEEK AND GENERATE A FEW SHOWERS
AND POSSIBLY THUNDERSTORMS. HIGH PRESSURE WILL MOVE INTO THE AREA
ON WEDNESDAY, RETURNING DRY WEATHER FOR THE MID-WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
ISOLATED SHOWERS ARE PERSISTING IN CENTRAL OHIO AND WILL PUSH
SLOWLY EAST INTO COSHOCTON AND MUSKINGUM COUNTIES. THE RISK OF
SHOWERS WILL DIMINISH INTO THE EARLY MORNING.
HAVE MAINTAINED SCHC POPS EARLY OVERNIGHT AS ANY LINGERING
CONVECTION SLIDES EAST OF THE AREA. THERE IS LOW CONFIDENCE IN
PATCHY FOG DEVELOPING IN THE RIVER VALLEYS DURING THE PRE-DAWN
HOURS AS THIS WILL BE DEPENDENT ON HOW MUCH RAINFALL LOCALITIES
RECEIVE TODAY. THUS, HAVE LEFT FOG OUT OF THE PUBLIC FORECAST AT
THIS TIME. OVERNIGHT TEMPS ARE CLOSER TO THE COOLER MAV GUIDANCE
WITH LOWS RANGING FROM THE LOW TO MID 50S ACROSS MUCH OF THE AREA.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
THERE IS ECMWF/GFS/NAM AGREEMENT THAT THE BROAD MID-LEVEL TROUGH
WILL REMAIN ACROSS THE OHIO VALLEY ON MONDAY AND AMPLIFY AS ITS
AXIS SWINGS INTO THE UPPER OHIO VALLEY LATE TUESDAY INTO
WEDNESDAY. WITH THE UPPER OHIO VALLEY IN A SOUTHWESTERLY FLOW
AHEAD OF THIS FEATURE AND THE MAJORITY OF MODEL SOLUTIONS SHOWING
WEAK INSTABILITY EACH DAY, CHC POPS WITH SCHC THUNDER IS FORECAST
FOR MONDAY WITH SCHC POPS/THUNDER ON TUESDAY. TEMPS WILL BE AROUND
5 DEGREES BELOW NORMAL THROUGH THIS PERIOD.
A MODEL CONSENSUS INDICATES THE TROUGH SLIDING EAST OF AREA AND
HIGH PRESSURE BUILDING IN FROM THE WEST ON WEDNESDAY. THIS WILL
ALLOW FOR A DRY FORECAST WITH MORE ABUNDANT SUNSHINE ON WEDNESDAY.
WITH INCREASED SUNSHINE TEMPS WILL WARM CLOSER TO SEASONAL NORMALS
ACROSS THE AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
CONSENSUS OF RECENT ECMWF AND NAEFS MODEL OUTPUT CONTINUES TO SHOW
BROAD HIGH PRESSURE UNDER WEAK FLOW ALOFT ACROSS THE EASTERN U.S.
INTO THE WEEKEND. HENCE, WILL MAINTAIN A FORECAST OF DRY AND
RELATIVELY CLOUD FREE CONDITIONS THROUGH THE PERIOD.
THIS SHOULD TRANSLATE TO EACH DAY HAVING A LARGER THAN NORMAL
DIURNAL TEMPERATURE RANGE. CONCUR WITH HPC THINKING, WITH SUPPORT
FROM GFS AND ECMWF MOS AND NAEFS MEDIAN VALUES, THAT LOWS THURSDAY
AND FRIDAY CAN BE UP TO 5 DEGREES COOLER THAN NORMAL, WHILE HIGHS BE
NEAR NORMAL. WITH POTENTIAL OF SURFACE DEW POINTS CLIMBING TO NEAR
NORMAL VALUES THIS WEEKEND, EXPECT WEEKEND LOWS TO LIKEWISE BE NEAR
NORMAL, WHILE HIGHS BE UP TO 5 DEGREES WARMER THAN NORMAL.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
EXPECT MAINLY VFR ACROSS THE UPPER OHIO VALLEY THROUGH 07Z.
PER BLEND OF RECENT RADAR DATA AND HRRR MODEL OUTPUT FORESEE ONLY
POTENTIAL OF RESTRICTIONS WOULD BE WITH ISOLATED SHOWERS AND
THUNDERSTORMS EARLY THIS EVENING.
LATEST GFS LAMP AND NAM MOS GUIDANCE FOR MOST TAF LOCATIONS
CONTINUES TO SHOW IFR RESTRICTIONS IN FOG 07Z-13Z. HOWEVER, AT
THIS JUNCTURE HAD ONLY ENOUGH CONFIDENCE TO INCLUDE MVFR
VISIBILITIES FOR MOST TAF SITES LATE TONIGHT...WITH A PERIOD OF
IFR AT KFKL AND KDUJ.
THE OTHER KEY TO FOG DEVELOPMENT LATE TONIGHT WOULD BE THE
LOCATION AND EXTENT OF SHOWERS EARLY TONIGHT AND THEIR SUBSEQUENT
EFFECT ON MOISTENING A SHALLOW TEMPERATURE-INVERSION CAPPED
SURFACE LAYER TONIGHT.
EXPECT THE REST OF MONDAY TO BE MAINLY VFR, ALTHOUGH AGAIN CANNOT
COMPLETELY RULE OUT THE POTENTIAL OF A BRIEF RESTRICTION WITH
ISOLATED AFTERNOON THUNDERSTORMS.
.OUTLOOK/ MONDAY NIGHT THROUGH FRIDAY/...
GENERALLY VFR CONDITIONS ARE EXPECTED. RESTRICTIONS MAY ACCOMPANY
SCATTERED THUNDERSTORMS MONDAY EVENING, AND PATCHY RIVER VALLEY
FOG EACH MORNING.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
752 PM EDT SUN AUG 19 2012
.SYNOPSIS...
A SERIES OF WEAK UPPER LEVEL LOW PRESSURE DISTURBANCES WILL CROSS
THE UPPER OHIO VALLEY EARLY THIS WEEK AND GENERATE A FEW SHOWERS
AND POSSIBLY THUNDERSTORMS. HIGH PRESSURE WILL MOVE INTO THE AREA
ON WEDNESDAY, RETURNING DRY WEATHER FOR THE MID-WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
ISOLATED SHOWERS ARE WEAKENING AS WE LOSE THE HEATING OF THE DAY.
A FEW ISOLATED LIGHTNING STRIKES ARE POSSIBLE IN THE RIDGES
EAST OF PITTSBURGH THROUGH THE NEXT SEVERAL HOURS. RISK OF
SHOWERS WILL CONTINUE TO DIMINISH INTO THE EARLY MORNING.
HAVE MAINTAINED SCHC POPS EARLY OVERNIGHT AS ANY LINGERING
CONVECTION SLIDES EAST OF THE AREA. THERE IS LOW CONFIDENCE IN
PATCHY FOG DEVELOPING IN THE RIVER VALLEYS DURING THE PRE-DAWN
HOURS AS THIS WILL BE DEPENDENT ON HOW MUCH RAINFALL LOCALITIES
RECEIVE TODAY. THUS, HAVE LEFT FOG OUT OF THE PUBLIC FORECAST AT
THIS TIME. OVERNIGHT TEMPS ARE CLOSER TO THE COOLER MAV GUIDANCE
WITH LOWS RANGING FROM THE LOW TO MID 50S ACROSS MUCH OF THE AREA.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
THERE IS ECMWF/GFS/NAM AGREEMENT THAT THE BROAD MID-LEVEL TROUGH
WILL REMAIN ACROSS THE OHIO VALLEY ON MONDAY AND AMPLIFY AS ITS
AXIS SWINGS INTO THE UPPER OHIO VALLEY LATE TUESDAY INTO
WEDNESDAY. WITH THE UPPER OHIO VALLEY IN A SOUTHWESTERLY FLOW
AHEAD OF THIS FEATURE AND THE MAJORITY OF MODEL SOLUTIONS SHOWING
WEAK INSTABILITY EACH DAY, CHC POPS WITH SCHC THUNDER IS FORECAST
FOR MONDAY WITH SCHC POPS/THUNDER ON TUESDAY. TEMPS WILL BE AROUND
5 DEGREES BELOW NORMAL THROUGH THIS PERIOD.
A MODEL CONSENSUS INDICATES THE TROUGH SLIDING EAST OF AREA AND
HIGH PRESSURE BUILDING IN FROM THE WEST ON WEDNESDAY. THIS WILL
ALLOW FOR A DRY FORECAST WITH MORE ABUNDANT SUNSHINE ON WEDNESDAY.
WITH INCREASED SUNSHINE TEMPS WILL WARM CLOSER TO SEASONAL NORMALS
ACROSS THE AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
CONSENSUS OF RECENT ECMWF AND NAEFS MODEL OUTPUT CONTINUES TO SHOW
BROAD HIGH PRESSURE UNDER WEAK FLOW ALOFT ACROSS THE EASTERN U.S.
INTO THE WEEKEND. HENCE, WILL MAINTAIN A FORECAST OF DRY AND
RELATIVELY CLOUD FREE CONDITIONS THROUGH THE PERIOD.
THIS SHOULD TRANSLATE TO EACH DAY HAVING A LARGER THAN NORMAL
DIURNAL TEMPERATURE RANGE. CONCUR WITH HPC THINKING, WITH SUPPORT
FROM GFS AND ECMWF MOS AND NAEFS MEDIAN VALUES, THAT LOWS THURSDAY
AND FRIDAY CAN BE UP TO 5 DEGREES COOLER THAN NORMAL, WHILE HIGHS BE
NEAR NORMAL. WITH POTENTIAL OF SURFACE DEW POINTS CLIMBING TO NEAR
NORMAL VALUES THIS WEEKEND, EXPECT WEEKEND LOWS TO LIKEWISE BE NEAR
NORMAL, WHILE HIGHS BE UP TO 5 DEGREES WARMER THAN NORMAL.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
EXPECT MAINLY VFR ACROSS THE UPPER OHIO VALLEY THROUGH 07Z.
PER BLEND OF RECENT RADAR DATA AND HRRR MODEL OUTPUT FORESEE ONLY
POTENTIAL OF RESTRICTIONS WOULD BE WITH ISOLATED SHOWERS AND
THUNDERSTORMS EARLY THIS EVENING.
LATEST GFS LAMP AND NAM MOS GUIDANCE FOR MOST TAF LOCATIONS
CONTINUES TO SHOW IFR RESTRICTIONS IN FOG 07Z-13Z. HOWEVER, AT
THIS JUNCTURE HAD ONLY ENOUGH CONFIDENCE TO INCLUDE MVFR
VISIBILITIES FOR MOST TAF SITES LATE TONIGHT...WITH A PERIOD OF
IFR AT KFKL AND KDUJ.
THE OTHER KEY TO FOG DEVELOPMENT LATE TONIGHT WOULD BE THE
LOCATION AND EXTENT OF SHOWERS EARLY TONIGHT AND THEIR SUBSEQUENT
EFFECT ON MOISTENING A SHALLOW TEMPERATURE-INVERSION CAPPED
SURFACE LAYER TONIGHT.
EXPECT THE REST OF MONDAY TO BE MAINLY VFR, ALTHOUGH AGAIN CANNOT
COMPLETELY RULE OUT THE POTENTIAL OF A BRIEF RESTRICTION WITH
ISOLATED AFTERNOON THUNDERSTORMS.
.OUTLOOK/ MONDAY NIGHT THROUGH FRIDAY/...
GENERALLY VFR CONDITIONS ARE EXPECTED. RESTRICTIONS MAY ACCOMPANY
SCATTERED THUNDERSTORMS MONDAY EVENING, AND PATCHY RIVER VALLEY
FOG EACH MORNING.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
706 PM EDT SUN AUG 19 2012
.SYNOPSIS...
A SERIES OF WEAK UPPER LEVEL LOW PRESSURE DISTURBANCES WILL CROSS
THE UPPER OHIO VALLEY EARLY THIS WEEK AND GENERATE A FEW SHOWERS
AND POSSIBLY THUNDERSTORMS. HIGH PRESSURE WILL MOVE INTO THE AREA
ON WEDNESDAY, RETURNING DRY WEATHER FOR THE MID-WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
ISOLATED SHOWERS ARE WEAKENING AS WE LOSE THE HEATING OF THE DAY.
A FEW ISOLATED LIGHTNING STRIKES ARE POSSIBLE IN THE RIDGES
EAST OF PITTSBURGH THROUGH THE NEXT SEVERAL HOURS. RISK OF
SHOWERS WILL CONTINUE TO DIMINISH INTO THE EARLY MORNING.
HAVE MAINTAINED SCHC POPS EARLY OVERNIGHT AS ANY LINGERING
CONVECTION SLIDES EAST OF THE AREA. THERE IS LOW CONFIDENCE IN
PATCHY FOG DEVELOPING IN THE RIVER VALLEYS DURING THE PRE-DAWN
HOURS AS THIS WILL BE DEPENDENT ON HOW MUCH RAINFALL LOCALITIES
RECEIVE TODAY. THUS, HAVE LEFT FOG OUT OF THE PUBLIC FORECAST AT
THIS TIME. OVERNIGHT TEMPS ARE CLOSER TO THE COOLER MAV GUIDANCE
WITH LOWS RANGING FROM THE LOW TO MID 50S ACROSS MUCH OF THE AREA.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
THERE IS ECMWF/GFS/NAM AGREEMENT THAT THE BROAD MID-LEVEL TROUGH
WILL REMAIN ACROSS THE OHIO VALLEY ON MONDAY AND AMPLIFY AS ITS
AXIS SWINGS INTO THE UPPER OHIO VALLEY LATE TUESDAY INTO
WEDNESDAY. WITH THE UPPER OHIO VALLEY IN A SOUTHWESTERLY FLOW
AHEAD OF THIS FEATURE AND THE MAJORITY OF MODEL SOLUTIONS SHOWING
WEAK INSTABILITY EACH DAY, CHC POPS WITH SCHC THUNDER IS FORECAST
FOR MONDAY WITH SCHC POPS/THUNDER ON TUESDAY. TEMPS WILL BE AROUND
5 DEGREES BELOW NORMAL THROUGH THIS PERIOD.
A MODEL CONSENSUS INDICATES THE TROUGH SLIDING EAST OF AREA AND
HIGH PRESSURE BUILDING IN FROM THE WEST ON WEDNESDAY. THIS WILL
ALLOW FOR A DRY FORECAST WITH MORE ABUNDANT SUNSHINE ON WEDNESDAY.
WITH INCREASED SUNSHINE TEMPS WILL WARM CLOSER TO SEASONAL NORMALS
ACROSS THE AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
CONSENSUS OF RECENT ECMWF AND NAEFS MODEL OUTPUT CONTINUES TO SHOW
BROAD HIGH PRESSURE UNDER WEAK FLOW ALOFT ACROSS THE EASTERN U.S.
INTO THE WEEKEND. HENCE, WILL MAINTAIN A FORECAST OF DRY AND
RELATIVELY CLOUD FREE CONDITIONS THROUGH THE PERIOD.
THIS SHOULD TRANSLATE TO EACH DAY HAVING A LARGER THAN NORMAL
DIURNAL TEMPERATURE RANGE. CONCUR WITH HPC THINKING, WITH SUPPORT
FROM GFS AND ECMWF MOS AND NAEFS MEDIAN VALUES, THAT LOWS THURSDAY
AND FRIDAY CAN BE UP TO 5 DEGREES COOLER THAN NORMAL, WHILE HIGHS BE
NEAR NORMAL. WITH POTENTIAL OF SURFACE DEW POINTS CLIMBING TO NEAR
NORMAL VALUES THIS WEEKEND, EXPECT WEEKEND LOWS TO LIKEWISE BE NEAR
NORMAL, WHILE HIGHS BE UP TO 5 DEGREES WARMER THAN NORMAL.
&&
.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
EXPECT MAINLY VFR ACROSS THE UPPER OHIO VALLEY THROUGH 07Z.
PER BLEND OF RECENT RADAR DATA AND HRRR MODEL OUTPUT FORESEE ONLY
POTENTIAL OF RESTRICTIONS WOULD BE WITH ISOLATED SHOWERS AND
THUNDERSTORMS LATE THIS AFTERNOON.
RECENT GFS LAMP AND NAM MOS CONTINUE TO SUPPORT THE IDEA OF AN IFR
RIVER VALLEY FOG EPISODE 07Z-13Z, THAT MAY AFFECT NEARBY TAF SITES.
HOWEVER, AT THIS JUNCTURE HAD ONLY ENOUGH CONFIDENCE TO INCLUDE MVFR
VISIBILITIES FOR MOST TAF SITES. DID MENTION IFR VISIBILITIES AT
KMGW, KHLG, AND KLBE, WHERE SURFACE DEW POINTS THIS AFTERNOON HAVE
CLIMBED INTO THE UPPER 50S, AN INDICATION THAT LATE NIGHT LOW
TEMPERATURES COULD BE COLDER THAN UPS FOG TECHNIQUE CROSSOVER
VALUES.
THE OTHER KEY TO FOG DEVELOPMENT LATE TONIGHT WOULD BE THE
LOCATION AND EXTENT OF SHOWERS LATE THIS AFTERNOON, AND THEIR
SUBSEQUENT EFFECT ON MOISTENING A SHALLOW TEMPERATURE-INVERSION
CAPPED SURFACE LAYER TONIGHT.
EXPECT THE REST OF MONDAY TO BE MAINLY VFR, ALTHOUGH AGAIN CANNOT
COMPLETELY RULE OUT THE POTENTIAL OF A BRIEF RESTRICTION WITH
ISOLATED AFTERNOON THUNDERSTORMS.
.OUTLOOK/ MONDAY NIGHT THROUGH FRIDAY/...
GENERALLY VFR. RESTRICTIONS MAY ACCOMPANY SCATTERED THUNDERSTORMS
MONDAY EVENING, AND PATCHY RIVER VALLEY FOG EACH MORNING.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
341 PM EDT SAT AUG 18 2012
.SYNOPSIS...
HIGH PRESSURE WILL ALLOW FOR DRY AND COOLER WEATHER TO CONTINUE
THROUGH TONIGHT. A SERIES OF A WEAK UPPER LEVEL DISTURBANCES WILL
CROSS THE AREA THROUGH MONDAY, BRINGING A FEW ISOLATED SHOWERS TO
THE AREA.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
THE LATEST RAP ANALYSIS INDICATES THE UPPER OHIO VALLEY IS AT THE
BASE OF WEAK CYCLONIC MID-LEVEL FLOW THAT IS ON THE DISTANT
SOUTHERN PERIPHERY OF A VORTEX CENTERED OVER THE HUDSON BAY. DRY
AIR IS IN PLACE IN THE 750-400MB LAYER. THIS COUPLED WITH SURFACE
HIGH PRESSURE EXTENDING FROM THE MIDWEST INTO THE OHIO VALLEY HAS
YIELDED A DRY DAY ACROSS THE AREA.
THE SURFACE HIGH WILL SLOWLY SLIDE EASTWARD TODAY AND TONIGHT,
ALLOWING FOR DRY WEATHER TO CONTINUE. TEMP DIFFERENTIAL BTW 850MB
AND A WARMER LAKE ERIE WITH AN INITIAL NORTHWESTERLY FLOW WILL
ALLOW FOR PARTLY CLOUDY SKIES TO CONTINUE INTO THE EARLY EVENING.
CUMULUS WILL QUICKLY DIMINISH AFTER SUNSET. SOME THIN CIRRUS WILL
ADVECT ACROSS THE AREA TONIGHT. WITH NEAR CALM WINDS, SOME RADIATIONAL
COOLING WILL OCCUR TONIGHT DESPITE PASSING CIRRUS. LOWS ARE SLIGHTLY
COOLER THAN A MAV/MET BLEND, RANGING FROM THE MID 40S ACROSS THE
I-80 CORRIDOR TO THE LOWER 50S ACROSS THE LOWLANDS ELSEWHERE.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
MODELS ARE IN AGREEMENT IN THE MID-LEVEL TROUGH ACROSS THE GREAT
LAKES AMPLIFYING WITH ITS AXIS CENTERED OVER LAKE MICHIGAN ON
SUNDAY. THERE IS SOME MODEL DISAGREEMENT IN REGARDS TO THE
INTENSITY OF VORT ENERGY SWINGING AROUND THE BOTTOM OF THE TROUGH
AND INTO THE UPPER OHIO VALLEY SUNDAY AFTERNOON. INCREASED MOISTURE
IN THE 850-700MB LAYER ALONG WITH STEEPENING LAPSE RATES WITH THE
POTENTIAL SHORT WAVE PASSAGE HAVE LED TO CHANCE POPS FORECAST WITH
SCHC THUNDER ON SUNDAY.
FOR TEMPS THROUGH SUNDAY NIGHT, AIR MASS IN PLACE WILL BE SIMILAR TO
THE PREVIOUS DAY WITH 850MB TEMPS IN THE 18-20C RANGE. THUS, HIGHS WILL
AGAIN RANGE FROM THE MID 70S ACROSS THE I-80 CORRIDOR AND EASTERN
RIDGES TO NEAR 80 IN PORTIONS OF EASTERN OHIO AND NORTH-CENTRAL WV.
ANOTHER NIGHT OF RADIATIONAL COOLING IS ANTICIPATED WITH LOWS AROUND
5 DEGREES BELOW NORMAL.
MONDAY INTO TUESDAY...THE MID-LEVEL TROUGH WILL CROSS THE OHIO
VALLEY WITH SOME MODEL UNCERTAINTY IN HOW FAST ITS AXIS TRANSLATES
INTO PENNSYLVANIA. ECMWF IS MORE AMPLIFIED WITH THIS FEATURE THAN
THE GFS. WITH THIS IN MIND CHC POPS AND SCHC THUNDER ARE FORECAST
IN ADVANCE OF THE TROUGH MONDAY. DEEP LAYER MOISTURE BEGINS TO
ADVECT EAST OF THE AREA BY TUESDAY MORNING, AND THUS POPS ARE
LIMITED TO LOCATIONS EAST OF PITTSBURGH ON TUESDAY. TEMPS WILL
CONTINUE TO BE AROUND 5 DEGREES BELOW NORMAL THROUGH THIS PERIOD.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
CONSENSUS OF RECENT ECMWF AND NAEFS MODEL OUTPUT SHOW BROAD HIGH
PRESSURE ACROSS THE EASTERN U.S. WILL MAINTAIN DRY CONDITIONS
THROUGH FRIDAY IF NOT SATURDAY.
BLEND OF GFS MOS, ECMWF MOS, AND NAEFS MEDIAN VALUES SHOW
TEMPERATURES WEDNESDAY CAN STILL BE SLIGHTLY COOLER THAN NORMAL. AS
HIGH PRESSURE CENTER TRANSITIONS TO THE EAST COAST, DAYTIME HIGH
TEMPERATURES WILL BECOME SLIGHTLY WARMER THAN NORMAL THURSDAY INTO
WEEKEND.
BY SATURDAY, LOW LEVEL SOUTHERLY WINDS WILL TRANSPORT SURFACE DEW
POINTS OF 60 TO 65 INTO THE UPPER OHIO VALLEY. SO EARLY MORNING LOW
TEMPERATURES SHOULD RETURN TO NEAR NORMAL VALUES THIS WEEKEND.
CONCUR WITH HPC THINKING THAT THERE CAN BE AT LEAST A SLIGHT CHANCE
OF SHOWERS BY SUNDAY.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
PER RECENT SURFACE AND SATELLITE DATA, EXPECT VFR THROUGH EARLY
TONIGHT, AS GENERALLY NO MORE THAN SCATTERED DAYTIME CUMULUS
EXPECTED TO DEVELOP THIS AFTERNOON.
SURFACE WINDS WILL BE MAINLY FROM THE NORTHWEST INCREASING TO
MORE THAN 7 KTS BY AFTERNOON.
PER BLEND OF RECENT NAM MODEL PROFILES AND GFS LAMP, PATCHY RIVER
VALLEY FOG MAY SPREAD MVFR VISIBILITIES TO SOME NEARBY TAF SITES
09Z-13Z.
AFTER THAT, MAINLY VFR DAYTIME SUNDAY, ALTHOUGH ISOLATED AFTERNOON
SHOWERS CAN DEVELOP.
.OUTLOOK/ SUNDAY NIGHT THROUGH THURSDAY/...
GENERALLY VFR. RESTRICTIONS MAY ACCOMPANY SCATTERED THUNDERSTORMS
MONDAY AFTERNOON AND EVENING AND PATCHY RIVER VALLEY FOG EACH
MORNING.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
142 PM EDT SAT AUG 18 2012
.SYNOPSIS...
HIGH PRESSURE WILL ALLOW FOR DRY AND COOLER WEATHER TO CONTINUE
THROUGH TONIGHT. COOLER WEATHER WILL CONTINUE ON SUNDAY, ALTHOUGH
AN UPPER LEVEL DISTURBANCE MAY BRING A FEW ISOLATED SHOWERS TO THE
AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED WITH MINOR
ADJUSTMENTS TO ACCOUNT FOR THE LATEST TRENDS IN TEMP AND SKY
GRIDS.
THE LATEST RAP ANALYSIS INDICATES THE UPPER OHIO VALLEY IS AT THE
BASE OF WEAK CYCLONIC MID-LEVEL FLOW THAT IS ON THE DISTANT
SOUTHERN PERIPHERY OF A VORTEX CENTERED OVER THE HUDSON BAY. DRY
AIR IS IN PLACE IN THE 750-400MB LAYER. THIS COUPLED WITH SURFACE
HIGH PRESSURE EXTENDING FROM THE MIDWEST INTO THE OHIO VALLEY HAS
YIELDED A DRY DAY ACROSS THE AREA.
THE SURFACE HIGH WILL SLOWLY SLIDE EASTWARD TODAY AND TONIGHT,
ALLOWING FOR DRY WEATHER TO CONTINUE. TEMP DIFFERENTIAL BTW 850MB
AND A WARMER LAKE ERIE WITH AN INITIAL NORTHWESTERLY FLOW WILL
ALLOW FOR DIURNAL CUMULUS TO CONTINUE ACROSS MOST OF THE AREA WITH
PARTLY CLOUDY SKIES TODAY. DIURNAL CUMULUS WILL QUICKLY DIMINISH
AFTER SUNSET. SOME THIN CIRRUS WILL ADVECT ACROSS THE AREA
TONIGHT. WITH NEAR CALM WINDS, RADIATIONAL COOLING WILL OCCUR
TONIGHT. LOWS ARE SLIGHTLY COOLER THAN A MAV/MET BLEND, RANGING
FROM THE MID 40S ACROSS THE I-80 CORRIDOR TO THE LOWER 50S ACROSS
THE LOWLANDS ELSEWHERE.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
THE UPPER OHIO VALLEY IS FORECAST TO REMAIN UNDER THE INFLUENCE OF
A JAMES BAY TO GULF COAST TROUGH THROUGH THE SHORT TERM PERIOD. ALTHOUGH
THE BOUNDARY LAYER MOISTURE FORECAST LOOKS RATHER LIMITED...STEEPENING
LAPSE RATES WITH A SHORTWAVE IN THE UPPER FLOW MAY SUPPORT SOME
ISOLATED TO SCATTERED SHOWERS ON SUNDAY. SLIGHT CHANCE POPS HAVE
THUS BEEN INTRODUCED...AND CONTINUED THROUGH MONDAY GIVEN THE
PRESENCE OF THE TROUGH AXIS PROJECTED TO LINGER OVER THE GREAT
LAKES AND OHIO VALLEY REGION. BY TUESDAY...THAT AXIS IS FORECAST
FAR ENOUGH EAST FOR A DRY FORECAST AS SURFACE HIGH PRES BUILD OVER
THE OHIO VALLEY. TEMPS UNDER THIS PATTERN ARE PROJECTED ABOUT 5
DEGREES UNDER THE AVERAGES USING TWEAKED SREF MEANS BLENDED WITH
THE LATEST MOS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
WEAK SURFACE HIGH PRESSURE THAT IS FORECAST TO REMAIN OVER THE REGION
THROUGHOUT THE WEEK WILL SUPPORT SEASONAL TEMPERATURES AND
GENERALLY DRY CONDITIONS.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
PER RECENT SURFACE AND SATELLITE DATA, EXPECT VFR THROUGH EARLY
TONIGHT, AS GENERALLY NO MORE THAN SCATTERED DAYTIME CUMULUS
EXPECTED TO DEVELOP THIS AFTERNOON.
SURFACE WINDS WILL BE MAINLY FROM THE NORTHWEST INCREASING TO
MORE THAN 7 KTS BY AFTERNOON.
PER BLEND OF RECENT NAM MODEL PROFILES AND GFS LAMP, PATCHY MVFR
RIVER VALLEY FOG MAY AFFECT SOME TAF SITES 10Z-13Z.
.OUTLOOK/ SUNDAY THROUGH WEDNESDAY/...
VFR.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
118 PM EDT SAT AUG 18 2012
.SYNOPSIS...
A COLD FRONT WHICH MOVED ACROSS THE AREA LAST NIGHT WILL STALL OUT
ACROSS SOUTHEAST VIRGINIA TODAY. THE BOUNDARY WILL RETURN NORTH
AS A WARM FRONT SUNDAY. A WAVE OF LOW PRESSURE MAY DEVELOP ALONG
THE BOUNDARY SUNDAY NIGHT INTO MONDAY. HIGH PRESSURE WILL SLOWLY
BUILD DURING THE MIDDLE PORTION OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLD FRONT HAS PUSHED SOUTHEAST OF THE AREA THIS MORNING...AND IS
LIKELY TO STALL OUT ACROSS EXTREME SOUTHEAST VIRGINIA OR THE
NORTHEAST NORTH CAROLINA COAST THIS AFTERNOON.
NORTH/NORTHWEST WINDS HAVE BROUGHT SOME DRIER AIR BOTH AT THE
SURFACE AND ALOFT ACROSS THE AREA. BUT WITH SOME COOLING ALOFT
ATOP THE WARM GROUND...EXPECT AT LEAST SCATTERED CUMULUS TO DOT
THE SKY THIS AFTERNOON.
MORE CLOUDS MAY BE FOUND ACROSS SOUTHERN MARYLAND AND THE LOWER
CHESAPEAKE BAY AREA CLOSER TO THE FRONT AND ALSO WITHIN THE UPPER
JET FLOW. THIS IS ALSO AN AREA WHERE ISOLATED SHOWERS MAY DEVELOP THIS
AFTERNOON PER THE WRF-ARW. HRRR IMPLIES THERE MAY BE SHOWERS
FURTHER NORTH AND WEST...BUT GIVEN DRYING AND WEAK FORCING HAVE
KEPT REST OF THE CWA DRY. MAXIMA ARE FORECAST TO BE SLIGHTLY BELOW
CLIMO.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
LIGHT NELY/ELY FLOW DEVELOPS WITH ISOLATED CHANCE FOR SHOWERS
EXPANDING WEST TO THE BLUE RIDGE. PLENTY OF CLOUDS WITH MIN TEMPS
MID TO UPR 50S PIEDMONT AND WEST...LOW TO MID 60S I-95 AND EAST.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
THIS XTND FCST IS "A STORY OF THE DIFFERENCES IN THE MDL POSNS OF
LAST NGT AND TNGT." LAST NGT NAM HAD A CLOSED SFC LOW OVR THE MID
ATLC SUNDAY WHILE THE GFS DVLPD IT OFFSHORE. TNGT THE CHG IS
FOCUSED ON SUN NGT/MON. GFS HAS CHGD TO HV THE SFC LOW DVLP UNDER
THE UPR TROF - FORMING IN THE TN VLLY SUN NGT AND MOVG OVR THE
DELMARVA MON EVE. THE NAM FORMS THE LOW OFF THE CST...SO
ESSENTIALLY A "180" FM THE PRVS NGT. THIS IN TURN GIVES CAT POPS
TO THE ENTIRE CWA FOR MON FM THE GFS...WHILE THE NAM RANGES FM LKLY
AT BALT TO NOTHING AT SHD.
I MUST SAY - LAST NGT I WAS VERY SUSPICIOUS WHEN THE NAM WENT SO
AGGRESSIVE W/ POPS...BUT AM LESS SO W/ THE NEW GFS APPROACH. LAST
YR I DID A STUDY ON GFS PERFORMANCE DURG THE SUMMER MONTHS AT THE
3 MAJOR AIRPORTS. FM 2009-11...DURG THE SUMMER...WHEN THE GFS
FCSTD 80 POP IN PD 5 - IN THIS CASE THAT`D BE MON...MEASURABLE
PCPN OCCURRED 14 OUT OF 14 TIMES. HIGH POPS CAN BE HARD TO JUSTIFY
IN SUMMER DUE TO THE "HIT OR MISS" NATURE OF CNVCTN...BUT IT`S
HARD TO ARGUE W/ THOSE NUMBERS...ESPECIALLY WHEN WE`RE NOT TALKING
ABT A CD FNT APRCHG FM THE NW.
ECM IS COMING IN AS I WRITE AT 315 AM. ITS SFC LOW IS NOT AS
TIGHT AS THE GFS DEPICTION BUT IT TOO HAS THE INCRSD RH IN THE E.
21Z SREF ALSO HAD A 50% CHC OF .05" FOR MON IN THE E.
SO FOR NOW HV INCRSD THE POPS FOR MON E OF THE MTNS FM CHC TO
LKLY...W/ HIGHEST NUMBERS ALONG THE BAY. IF THE SYNOPTIC PATTERN
PLAYS OUT LK I`M BEGINING TO THINK IT WL PCPN MOST LKLY WL BE RW
W/ EMBEDDED T PSBL. AM NOT THINKING A SVR OUTBRK GIVEN ERLY FLOW
AND DEEP CLD CVR. THE PCPN WOULD MOST LKLY BE EXITING THE AREA DURG MON
AFTN...SO FLDG NOT A CONCERN.
AFTR MON HIGH PRES LOOKS TO BLD IN FOR TUE-FRI. TEMPWISE THE WK
AHD SHOULD BE QUITE PLSNT W/ DAYS W/ HIGHS IN THE LM80S AND NGTS
RANGING FM THE M50S IN THE MTNS TO L70S ON THE CHES BAY. FM I-81
TO I-95 WL DROP INTO THE 60S.
&&
.AVIATION /17Z SATURDAY THROUGH WEDNESDAY/...
VFR TODAY WITH FRONT STALLING OUT OVER FAR SOUTHEAST VIRGINIA.
EXPECT SHOWERS TO REMAIN SOUTHEAST OF THE TERMINALS. N/NW WINDS
MAY BE 10 TO 15 KT AT TIMES DURING THE AFTERNOON.
CIGS MAY DROP INTO MVFR CAT SUN NGT AND MON AS LOW PRES TRACKS
ACROSS THE ERN PORTION OF THE FCST AREA. ISOLD TSTMS WOULD BE
PSBL. HIGH PRES TO BUILD IN TUE THRU THU.
&&
.MARINE...
NORTHERLY WINDS HAVE BEEN DIMINISHING OVER THE LAST COUPLE OF
HOURS AND THE LATEST COVM2 OB DROPPED TO 17 KT. TREND SHOULD
CONTINUE AND THUS SCA WILL BE CANCELLED. EXPECT 10 TO 15 KT FOR
THE REST OF THE AFTERNOON.
THERE IS SOME DIFFERENCE IN THE MDLS REGARDING THE DVLPMNT OF A
LOW PRES AREA TO OUR SW SUN MOVG INTO THE WATERS MON. IF THIS DOES
COMES TRUE MON MAY BE WETTER THAN PRVSLY THOT. THERE MAY ALSO BE A
PD OF SCA-LVL WINDS.
HIGH PRES LOOKS TO MOVE INTO THE MID ATLC TUE-FRI.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
BPP/BAJ/WOODY!
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1102 AM EDT SAT AUG 18 2012
.SYNOPSIS...
HIGH PRESSURE WILL ALLOW FOR DRY AND COOLER WEATHER TO CONTINUE
THROUGH TONIGHT. COOLER WEATHER WILL CONTINUE ON SUNDAY, ALTHOUGH
AN UPPER LEVEL DISTURBANCE MAY BRING A FEW ISOLATED SHOWERS TO THE
AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
15Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO REMOVE
MORNING FOG WORDING AND TO INCREASE CLOUD COVERAGE TODAY.
THE LATEST RAP ANALYSIS INDICATES THE UPPER OHIO VALLEY IS AT THE
BASE OF WEAK CYCLONIC MID-LEVEL FLOW THAT IS ON THE DISTANT
SOUTHERN PERIPHERY OF A VORTEX CENTERED OVER THE HUDSON BAY. DRY
AIR IS IN PLACE IN THE 750-400MB LAYER. THIS COUPLED WITH SURFACE
HIGH PRESSURE EXTENDING FROM THE MIDWEST INTO THE OHIO VALLEY HAS
YIELDED A DRY DAY ACROSS THE AREA.
THE SURFACE HIGH WILL SLOWLY SLIDE EASTWARD TODAY AND TONIGHT,
ALLOWING FOR DRY WEATHER TO CONTINUE. TEMP DIFFERENTIAL BTW 850MB
AND A WARMER LAKE ERIE WITH AN INITIAL NORTHWESTERLY FLOW WILL
ALLOW FOR DIURNAL CUMULUS TO DEVELOP ACROSS MOST OF THE AREA WITH
PARTLY CLOUDY SKIES TODAY. DIURNAL CUMULUS THAT DEVELOPS WILL
QUICKLY DIMINISH AFTER SUNSET. SOME THIN CIRRUS WILL ADVECT ACROSS
THE AREA TONIGHT. WITH NEAR CALM WINDS, RADIATIONAL COOLING WILL
OCCUR TONIGHT. LOWS ARE SLIGHTLY COOLER THAN A MAV/MET BLEND,
RANGING FROM THE UPPER 40S ACROSS THE I-80 CORRIDOR AND EASTERN
RIDGES TO THE LOWER 50S ELSEWHERE.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
THE UPPER OHIO VALLEY IS FORECAST TO REMAIN UNDER THE INFLUENCE OF
A JAMES BAY TO GULF COAST TROUGH THROUGH THE SHORT TERM PERIOD. ALTHOUGH
THE BOUNDARY LAYER MOISTURE FORECAST LOOKS RATHER LIMITED...STEEPENING
LAPSE RATES WITH A SHORTWAVE IN THE UPPER FLOW MAY SUPPORT SOME
ISOLATED TO SCATTERED SHOWERS ON SUNDAY. SLIGHT CHANCE POPS HAVE
THUS BEEN INTRODUCED...AND CONTINUED THROUGH MONDAY GIVEN THE
PRESENCE OF THE TROUGH AXIS PROJECTED TO LINGER OVER THE GREAT
LAKES AND OHIO VALLEY REGION. BY TUESDAY...THAT AXIS IS FORECAST
FAR ENOUGH EAST FOR A DRY FORECAST AS SURFACE HIGH PRES BUILD OVER
THE OHIO VALLEY. TEMPS UNDER THIS PATTERN ARE PROJECTED ABOUT 5
DEGREES UNDER THE AVERAGES USING TWEAKED SREF MEANS BLENDED WITH
THE LATEST MOS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
WEAK SURFACE HIGH PRESSURE THAT IS FORECAST TO REMAIN OVER THE REGION
THROUGHOUT THE WEEK WILL SUPPORT SEASONAL TEMPERATURES AND
GENERALLY DRY CONDITIONS.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
EXPECT REMAINING MVFR STRATUS CLOUD BANK NEAR THE MOUNTAINS AND
AFFECTING TAF SITES SUCH AS KLBE AND KMGW TO DISSIPATE BEFORE 16Z.
AFTER THAT, NONSTOP VFR AS GENERALLY NO MORE THAN SCATTERED DAYTIME
CUMULUS EXPECTED TO DEVELOP THIS AFTERNOON.
SURFACE WINDS WILL BE MAINLY FROM THE NORTHWEST INCREASING TO
MORE THAN 8 KTS BY AFTERNOON.
.OUTLOOK/ SUNDAY THROUGH WEDNESDAY/...
VFR.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1031 AM EDT SAT AUG 18 2012
.SYNOPSIS...
A COLD FRONT WHICH MOVED ACROSS THE AREA LAST NIGHT WILL STALL OUT
ACROSS SOUTHEAST VIRGINIA TODAY. THE BOUNDARY WILL RETURN NORTH
AS A WARM FRONT SUNDAY. A WAVE OF LOW PRESSURE MAY DEVELOP ALONG
THE BOUNDARY...IMPACTING THE WATERS SUNDAY NIGHT INTO MONDAY. HIGH
PRESSURE WILL SLOWLY BUILD TOWARD THE WATERS DURING THE MIDDLE
PORTION OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLD FRONT HAS PUSHED SOUTHEAST OF THE AREA THIS MORNING...AND IS
LIKELY TO STALL OUT ACROSS EXTREME SOUTHEAST VIRGINIA OR THE
NORTHEAST NORTH CAROLINA COAST THIS AFTERNOON.
NORTH/NORTHWEST WINDS HAVE BROUGHT SOME DRIER AIR BOTH AT THE
SURFACE AND ALOFT ACROSS THE AREA. BUT WITH SOME COOLING ALOFT
ATOP THE WARM GROUND...EXPECT AT LEAST SCATTERED CUMULUS TO DOT
THE SKY THIS AFTERNOON.
MORE CLOUDS MAY BE FOUND ACROSS SOUTHERN MARYLAND AND THE LOWER
CHESAPEAKE BAY AREA CLOSER TO THE FRONT AND ALSO WITHIN THE UPPER
JET FLOW. THIS IS ALSO AN AREA WHERE ISOLATED SHOWERS MAY DEVELOP THIS
AFTERNOON PER THE WRF-ARW. HRRR IMPLIES THERE MAY BE SHOWERS
FURTHER NORTH AND WEST...BUT GIVEN DRYING AND WEAK FORCING HAVE
KEPT REST OF THE CWA DRY. MAXIMA ARE FORECAST TO BE SLIGHTLY BELOW
CLIMO.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
LIGHT NELY/ELY FLOW DEVELOPS WITH ISOLATED CHANCE FOR SHOWERS
EXPANDING WEST TO THE BLUE RIDGE. PLENTY OF CLOUDS WITH MIN TEMPS
MID TO UPR 50S PIEDMONT AND WEST...LOW TO MID 60S I-95 AND EAST.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
THIS XTND FCST IS "A STORY OF THE DIFFERENCES IN THE MDL POSNS OF
LAST NGT AND TNGT." LAST NGT NAM HAD A CLOSED SFC LOW OVR THE MID
ATLC SUNDAY WHILE THE GFS DVLPD IT OFFSHORE. TNGT THE CHG IS
FOCUSED ON SUN NGT/MON. GFS HAS CHGD TO HV THE SFC LOW DVLP UNDER
THE UPR TROF - FORMING IN THE TN VLLY SUN NGT AND MOVG OVR THE
DELMARVA MON EVE. THE NAM FORMS THE LOW OFF THE CST...SO
ESSENTIALLY A "180" FM THE PRVS NGT. THIS IN TURN GIVES CAT POPS
TO THE ENTIRE CWA FOR MON FM THE GFS...WHILE THE NAM RANGES FM LKLY
AT BALT TO NOTHING AT SHD.
I MUST SAY - LAST NGT I WAS VERY SUSPICIOUS WHEN THE NAM WENT SO
AGGRESSIVE W/ POPS...BUT AM LESS SO W/ THE NEW GFS APPROACH. LAST
YR I DID A STUDY ON GFS PERFORMANCE DURG THE SUMMER MONTHS AT THE
3 MAJOR AIRPORTS. FM 2009-11...DURG THE SUMMER...WHEN THE GFS
FCSTD 80 POP IN PD 5 - IN THIS CASE THAT`D BE MON...MEASURABLE
PCPN OCCURRED 14 OUT OF 14 TIMES. HIGH POPS CAN BE HARD TO JUSTIFY
IN SUMMER DUE TO THE "HIT OR MISS" NATURE OF CNVCTN...BUT IT`S
HARD TO ARGUE W/ THOSE NUMBERS...ESPECIALLY WHEN WE`RE NOT TALKING
ABT A CD FNT APRCHG FM THE NW.
ECM IS COMING IN AS I WRITE AT 315 AM. ITS SFC LOW IS NOT AS
TIGHT AS THE GFS DEPICTION BUT IT TOO HAS THE INCRSD RH IN THE E.
21Z SREF ALSO HAD A 50% CHC OF .05" FOR MON IN THE E.
SO FOR NOW HV INCRSD THE POPS FOR MON E OF THE MTNS FM CHC TO
LKLY...W/ HIGHEST NUMBERS ALONG THE BAY. IF THE SYNOPTIC PATTERN
PLAYS OUT LK I`M BEGINING TO THINK IT WL PCPN MOST LKLY WL BE RW
W/ EMBEDDED T PSBL. AM NOT THINKING A SVR OUTBRK GIVEN ERLY FLOW
AND DEEP CLD CVR. THE PCPN WOULD MOST LKLY BE EXITING THE AREA DURG MON
AFTN...SO FLDG NOT A CONCERN.
AFTR MON HIGH PRES LOOKS TO BLD IN FOR TUE-FRI. TEMPWISE THE WK
AHD SHOULD BE QUITE PLSNT W/ DAYS W/ HIGHS IN THE LM80S AND NGTS
RANGING FM THE M50S IN THE MTNS TO L70S ON THE CHES BAY. FM I-81
TO I-95 WL DROP INTO THE 60S.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
VFR TODAY WITH FRONT STALLING OUT OVER FAR SOUTHEAST VIRGINIA.
EXPECT SHOWERS TO REMAIN SOUTHEAST OF THE TERMINALS. N/NW WINDS
MAY BE 10 TO 15 KT AT TIMES DURING THE AFTERNOON.
CIGS MAY DROP INTO MVFR CAT SUN NGT AND MON AS LOW PRES TRACKS
ACROSS THE ERN PORTION OF THE FCST AREA. ISOLD TSTMS WOULD BE
PSBL. HIGH PRES TO BUILD IN TUE THRU THU.
&&
.MARINE...
NORTHERLY WINDS HAVE BEEN DIMINISHING OVER THE LAST COUPLE OF
HOURS AND THE LATEST COVM2 OB DROPPED TO 17 KT. TREND SHOULD
CONTINUE AND THUS SCA WILL BE CANCELLED. EXPECT 10 TO 15 KT FOR
THE REST OF THE AFTERNOON.
THERE IS SOME DIFFERENCE IN THE MDLS REGARDING THE DVLPMNT OF A
LOW PRES AREA TO OUR SW SUN MOVG INTO THE WATERS MON. IF THIS DOES
COMES TRUE MON MAY BE WETTER THAN PRVSLY THOT. THERE MAY ALSO BE A
PD OF SCA-LVL WINDS.
HIGH PRES LOOKS TO MOVE INTO THE MID ATLC TUE-FRI.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
BPP/BAJ/WOODY!
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
815 PM EDT SUN AUG 19 2012
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 332 PM EDT SUN AUG 19 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF OVER
ERN NAMERICA AND ARND CLOSED UPR LO NEAR JAMES BAY DOWNSTREAM OF UPR
RDG OVER THE ROCKIES. RUC ANALYSIS INDICATES A SHRTWV EMBEDDED
WITHIN THE UPR TROF IS OVER LK SUP. THIS DISTURBANCE/HINT OF SFC LO
PRES TROF SUPPORTED SOME SCT -SHRA MAINLY OVER CNTRL UPR MI INTO
EARLY AFTN. BUT DESPITE SOME SFC HEATING...THERE ARE NO MORE THAN
ISOLD -SHRA NOW OVER THE SCNTRL DESPITE SOME LK BREEZE CNVGC IN THAT
AREA. LLVL DRY AIR APPEARS TO BE THE MAIN LIMITING FACTOR AS SFC
DEWPTS HAVE MIXED OUT TO 40 TO 45 AT MOST SPOTS. ANOTHER STRONGER
DISTURBANCE ROTATING ARND THE PARENT UPR LO IS NOTED ON WV IMAGERY
OVER NRN ONTARIO. WHERE THE MSTR IS DEEPEST ON THE CYC SIDE OF THIS
FEATURE...THICK CLD COVER IS PRESENT OVER MUCH OF ONTARIO EXCEPT THE
FAR W. MUCH DRIER AIRMASS SHOWN ON THE 12Z INL/YPL RAOBS...WHERE
PWAT IS 0.38/0.41 INCH RESPECTIVELY OR NEAR 50 PCT OF NORMAL...IS
ALLOWING CLR-PCLDY CONDITIONS FM NRN MN THRU MOST OF WRN ONTARIO.
BUT THERE IS ANOTHER PATCH OF CLDS OVER FAR NW ONTARIO/ADJOINING
MANITOBA ASSOCIATED WITH YET ANOTHER SHRTWV DIVING SSEWD E OF LK
WINNIPEG WITHIN THE NNW FLOW ALF.
TONIGHT...EXPECT ANY LINGERING -SHRA OVER MAINLY THE SCNTRL TO END
THIS EVNG WITH EXIT OF SHRTWV NOW OVER LK SUP AND LOSS OF DAYTIME
HEATING. ALTHOUGH THE EVNG WL THEN TURN MOCLR EXCEPT FOR SOME PATCHY
HI CLDS WITH DRY AIR SHOWN ON THE 12Z INL/YPL RAOBS DOMINATING...
BULK OF GUIDANCE INDICATES SHRTWV NOW DIVING SWD THRU NRN ONTARIO WL
DIVE SWD TO NEAR ISLE ROYALE BY 12Z MON. SO EVEN THOUGH ALL MODELS
SHOW BULK OF THICKER CLD NOW DOMINATING MUCH OF ONTARIO ON THE CYC
SIDE OF SHRTWV TRACK WL REMAIN TO THE NE OF THE CWA UNDER LOWER H85
TEMPS...SUSPECT MORE CLDS WL ARRIVE OVER AT LEAST THE NRN TIER LATER
TNGT. WITH A PERIOD OF MOCLR SKIES THRU AT LEAST THE EVNG INTO EARLY
OVERNGT...EXPECT A QUICK DROP OF TEMPS. THE COOLEST OVERNGT MINS
INTO THE UPR 30S ARE MOST LIKELY OVER THE SRN TIER...WHERE MORE CLDS
ASSOCIATED WITH INCOMING SHRTWV ARE LIKELY NOT TO ARRIVE BEFORE
SUNRISE.
MON...INCOMING SHRTWV IS PROGGED TO SLIDE SWD ACRS WRN UPR MI AND
INTO WI IN THE AFTN. SINCE THE CWA WL BE ON THE CYC SIDE OF THE
TRACK OF THIS DISTURBANCE AND ACCOMPANYING DPVA/SOME DEEP LYR
QVECTOR CNVGC WL OCCUR DURING PEAK HEATING TIME...EXPECT AT LEAST
ISOLD -SHRA TO IMPACT MAINLY THE SCNTRL...WHERE SOME LK BREEZE CNVGC
MIGHT ENHANCE PCPN POTENTIAL. POPS WL BE LIMITED BY LLVL DRY AIR AND
LO KINX FCST NO HIER THAN 25 TO 30. WITH H85 TEMPS FCST IN THE 7 TO
9C RANGE...EXPECT HI TEMPS TO PEAK NOT FAR FM 70.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 332 PM EDT SUN AUG 19 2012
OVERALL GOOD MODEL AGREEMENT THROUGH WED...LEADING TO INCREASED
FORECAST CONFIDENCE FOR THIS TIME PERIOD.
STARTING THE PERIOD 00Z TUE...A SHORTWAVE TROUGH WILL BE EXITING THE
WA TO THE SE...ROTATING AROUND THE UPPER LEVEL LOW OVER NW QUEBEC
AND THE UPPER TROUGH OVER MUCH OF THE ERN HALF OF THE CONUS. THERE
MAY BE SOME SHOWERS EARLY ON MON NIGHT FROM THIS PASSING
THROUGH...BUT COVERAGE SHOULD BE LIMITED DUE TO THE DRY AIRMASS
OVERHEAD. WEAK UPPER RIDGING QUICKLY MOVES IN BEHIND THE
SHORTWAVE...EXTENDING FROM A RIDGE OVER THE WRN CONUS.
MODELS DO NOT SHOW ANY WAVES MOVING THROUGH ON TUE...BUT GIVEN NW
FLOW ALOFT IT IS HARD TO COMPLETELY RULE OUT AFTERNOON PRECIP...BUT
FOR NOW WILL LEAVE PRECIP OUT OF THE FORECAST. WITH ONLY SCATTERED
CU FOR CLOUDS...850MB TEMPS AOA 12MB SHOULD LEAD TO HIGH TEMPS IN
THE MID TO UPPER 70S...WITH A FEW LOW 80S POSSIBLE.
A WEAK SHORTWAVE TROUGH IS THEN SET TO MOVE NEAR THE CWA WED...ALSO
BRINGING A COLD FRONT INTO THE AREA. LIMITED MOISTURE AND
UNCERTAINTY REGARDING THE STRENGTH AND TRACK OF THE SHORTWAVE HAS
LEAD TO LIMITED CONFIDENCE WITH THIS SYSTEM...SO KEPT PRECIP CHANCES
ON THE LOW SIDE. HIGH TEMPS SHOULD BE SIMILAR TO TUE.
FOR WED NIGHT THROUGH NEXT SUN...MODELS SHOW THE COLD FRONT FROM WED/WED
NIGHT STALLING OVER OR NEAR THE CWA THU THROUGH FRI UNTIL AN
UPPER/SFC TROUGH MOVE THROUGH FRI NIGHT AND SAT. MODELS ALSO SHOW A
STRONGER UPPER LOW MOVING ACROSS SRN CANADA STARTING WED
NIGHT...THEN MOVING TO MANITOBA BY 00Z NEXT MON. WHEREAS THE 00Z/19
GFS AND 00Z/19 ECMWF AGREE PRETTY WELL ON THE LARGE SCALE
PATTERN...THE ECMWF HAS HAD VERY POOR RUN TO RUN CONTINUITY. THE GFS
ON THE OTHER HAND HAS SHOWN FAIRLY GOOD RUN TO RUN
CONTINUITY...LEADING TO MORE CONFIDENCE IN THE GFS SOLUTION BUT LOW
FORECAST CONFIDENCE OVERALL FOR THU ON. DID NOT SPEND TOO MUCH TIME
ON THIS PART OF THE FORECAST GIVEN LIMITED CONFIDENCE...AND SINCE
CONSENSUS OF MODEL DATA /WHICH FAVORS THE GFS/ LOOKED
REASONABLE...SO JUST USED THAT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 807 PM EDT SUN AUG 19 2012
ALTHOUGH DISTURBANCES ROTATING AROUND A DEEP CLOSED LOW NEAR JAMES BAY
WILL BRING PERIODS OF CLOUDS TO UPPER MI THIS FCST PERIOD...EXPECT VFR
CONDITIONS TO PREVAIL WITH RELATIVELY DRY NEAR SFC LAYER. ALTHOUGH
THERE COULD BE SOME FOG MAINLY AT SAW/IWD TONIGHT WITH LIGHT WINDS
UNDER WEAK SFC HI PRES RIDGE...NO FOG WAS OBSERVED UPSTREAM LAST
NIGHT WITHIN THE DRY AIRMASS DEPICTED ON THE 12Z INL/YPL RAOBS. SO
KEPT A MENTION OF FOG OUT OF TAFS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 332 PM EDT SUN AUG 19 2012
EXPECT WINDS NO HIER THAN 20 KTS THRU THU WITH WEAK PRES GRADIENT
DOMINATING THE UPPER GREAT LAKES. SINCE HI PRES WILL DOMINATE MOST
OF THE TIME UNTIL LATER IN THE WEEK...THERE WILL BE LITTLE THREAT OF
PRECIPITATION UNTIL THU.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...JLB
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
401 PM EDT SAT AUG 18 2012
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 359 PM EDT SAT AUG 18 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF OVER
ERN NAMERICA CENTERED AROUND CUTOFF UPR LO NEAR JAMES BAY. THERE ARE
SEVERAL SHRTWVS ROTATING THRU THE TROF AND ARND THIS FEATURE. THE
FIRST IS SETTLING S THRU ONTARIO WHILE ANOTHER NEAR LK WINNIPEG IS
DIVING SSEWD TOWARD NW MN. AT 15Z...THESE SHRTWVS/ACCOMPANYING SFC
TROF OVER LK SUP WITH SHARP WSHFT WERE SUPPORTING A BKN LINE OF SHRA
EXTENDING FM ERN LK SUP ACRS THE KEWEENAW THRU NRN MN TOWARD LK
WINNIPEG. THE 12Z INL RAOB SHOWS ABUNDANT MID LVL MSTR ABV A DRIER
SUB H75 LYR...AND THIS LOWER LVL DRY AIR SEEMS TO BE THE BIGGEST
IMPEDIMENT TO MORE WDSPRD SHRA. THE DRY AIR IS DEEPER TO THE S AS
INDICATED BY THE 12Z GRB RAOB...AND THE MRNG WAS MOSUNNY OVER THE
SCNTRL. TO THE N...MUCH DRIER LLVL AIR IS PRESENT ON THE 12Z YPL
RAOB UNDER HI PRES RDG AXIS EXTENDING SEWD INTO NW ONTARIO FM HI
PRES CENTERED OVER NRN MANITOBA. MODIFIED
LATE THIS AFTN...WITH ARRIVAL OF SFC TROF/ENHANCED LLVL CNVGC
ASSOCIATED WITH SHARP SYNOPTIC WSHFT THAT WL BE ENHANCED BY
BREEZE OFF LK SUP DURING PEAK HEATING TIME...THE SHRA HAVE BECOME
MORE NMRS WITH SOME EMBEDDED TS ON A LINE THRU THE CNTRL ZNS.
MODIFIED 12Z INL RAOB FOR SFC T/TD OF 75/47 YIELDS SBCAPE UP TO 600
J/KG. ALTHOUGH SHRA COVERAGE IS STILL LIMITED OVER THE SCNTRL BY
LINGERING LLVL DRY AIR...EXPECT THESE SHRA TO SPREAD INTO THAT AREA
AS THE DRY AIR RETREATS. THE INTENSITY OF THE TS WL BE LIMITED BY
DRY LLVL AIR...ENVIRONMENTAL LAPSE RATES NOT FAR FM MOIST
ADIABATIC/DEEP SKINNY CAPE...LACK OF MID LVL DRY AIR THAT KEEPS
SFC-10K FT DELTA THETA-E NO HIER THAN 5-10C...AND RELATIVELY WEAK
DEEP LYR SHEAR NO GREATER THAN 15-25 KTS. ALTHOUGH SOME STORMS HAVE
PULSED AT TIMES...THE SMALL CORES HAVE NOT PERSISTED AND REMAINED
NEARLY VERTICAL...CONSISTENT WITH A WEAK SHEAR ENVIRONMENT. LO FRZG
LVL NOT FAR FM 9K FT AGL INDICATES THE STRONGER CELLS MIGHT DROP
SOME SMALL HAIL.
TONIGHT...MAIN FCST CONCERNS BECOME HOW QUICKLY DRIER AIR OVER
ONTARIO CAN MOVE INTO THE UPR LKS AND COUNTER LINGERING DYNAMIC
SUPPORT ASSOCIATED WITH DISTURBANCE NOW NEAR LK WINNIPEG THAT IS
FCST TO DROP SEWD INTO NW WI BY 12Z SUN AND SHARPEN UPR TROF AXIS
EXTENDING FM CLOSED LO NEAR JAMES BAY SWWD THRU UPR MI. LOSS OF
DAYTIME HEATING WL ALSO ENHANCE SHRA DISSIPATION. THE NAM IS MOST
AGGRESSIVE WITH UPR DRYING AND SHOWS ANY LINGERING -SHRA OVER THE
SCNTRL ENDING BY 03Z. THE BULK OF THE OTHER GUIDANCE MAINTAINS THE
-SHRA MAINLY OVER THE SCNTRL THRU MUCH OF THE NGT. HOWEVER...
CONSIDERING THE LLVL DRYNESS OF THE 12Z YPL RAOB AND RATHER
AGGRESSIVE DRYING TAKING PLACE OVER THE N PORTIONS OF LK SUP/
ADJOINING ONTARIO...THE NAM MIGHT BE ON THE RIGHT TRACK. SINCE ALL
THE MODELS ALSO SHOW LIMITED DEEP LYR QVECTOR CVNGC AS ANY DPVA
AHEAD OF SHRTWV IS OFFSET BY DRYING...TENDED TO CUT POPS A BIT
FASTER THAN GOING FCST WITH SMALL CHC POPS LINGERING ONLY OVER THE
FAR SCNTRL NEAR MNM LATER TNGT. ALTHOUGH LGT WINDS ASSOCIATED WITH
BLDG HI PRES MOVING TOWARD WRN UPR MI TOWARD 12Z/AGGRESSIVE MID LVL
DRYING MIGHT SUPPORT FOG FORMATION ESPECIALLY IN AREAS THAT GET RA
THIS AFTN/EVNG...WL KEEP FOG OUT OF FCST EXCEPT FOR OVER THE
INTERIOR WCNTRL...WHERE THE GFS HINTS THE LLVL DRYING WL BE LESS
PRONOUNCED AND SREF PROB VSBY UNDER 1 MILE IS HIER AND WHERE MIN
TEMPS ARE LIKELY TO BE LOWEST ARND 40.
SUN...CWA IS FCST TO REMAIN UNDER UPR TROF EXTENDING SWWD FM HUDSON
BAY. THE 12Z NAM/LOCAL WRF-ARW SHOW A SFC RDG AXIS EXTENDING FM WRN
LK SUP THRU THE CWA BRINGING A DRY DAY. THE 12Z GFS/CNDN MODELS ON
OTHER HAND SHOW A WEAKER SFC RDG...WITH A WEAKER GRADIENT ALLOWING
SOME LK BREEZE CNVGC/WEAK LO PRES TROF OVER THE SCNTRL...WHERE THESE
MODELS GENERATES SOME INSTABILITY -SHRA IN THE AFTN. CONSIDERING THE
WARM/DRY H7-5 LYR/LO FCST KINX ARND 18 BY THE GFS IN THIS AREA...
OPTED TO MAINTAIN GOING DRY FCST. WITH H85 TEMPS FCST TO BE ARND 8C
AND MIXING TO H75 ON GFS FCST SDNGS...EXPECT HI TEMPS TO REACH THE
MID 70S NEAR THE WI BORDER/SCNTRL AWAY FM LK MODERATION.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 359 PM EDT SAT AUG 18 2012
UPPER-LEVEL CONDITIONS WILL REMAIN SUPPORTIVE OF A SUBTLE SERIES OF
TROUGHS AND RIDGES THROUGH MONDAY. DRY CONDITIONS WILL THEN BUILD IN
FOR THE MIDDLE OF THE WEEK BEFORE A WARM...AND POTENTIALLY WET...END
TO THE WEEK.
SUNDAY NIGHT AND MONDAY...NAM/GFS/ECMWF/GEM HAVE COME INTO GOOD
AGREEMENT ON THE SYNOPTIC PATTERN ACROSS CENTRAL AND EASTERN NORTH
AMERICA THROUGH TUESDAY...SO OVERALL CONFIDENCE OF THE FORECAST IN
THIS TIME PERIOD IS FAIRLY GOOD.
A PERSISTENT MID-LEVEL LOW OVER JAMES BAY WILL BEGIN TO MOVE
NORTHEAST SUNDAY NIGHT AS A BROAD MID-LEVEL RIDGE OVER THE WESTERN
THIRD OF THE CONUS COMMENCES DEAMPLIFICATION WHILE DRIFTING EASTWARD
TOWARD THE UPPER GREAT LAKES REGION. A SERIES OF SHORTWAVE TROUGHS
WILL CONTINUE TO TRACK AROUND THE BACKSIDE OF THE LOW OVER JAMES
BAY. THE FIRST OF THOSE IS MOVING THROUGH THE AREA TODAY. THEN...A
SECOND TROUGH BEHIND TODAYS TROUGH WILL CROSS THE AREA ON
SUNDAY...AND BE EXITING TO THE SOUTHEAST OUT OF UPPER MI BY SUNDAY
EVENING. A SHORTWAVE RIDGE WILL THEN BRIEFLY MOVE IN SUNDAY EVENING
AHEAD OF YET ANOTHER WEAK SHORTWAVE TROUGH CROSSING THE CWA ON
MONDAY.
THE WEAK INCOMING RIDGE COMBINED WITH PLENTY OF DRY AIR THROUGHOUT
THE COLUMN SHOULD LIMIT THE CHANCE OF ANY PRECIP BY SUNDAY EVENING.
ATTENTION IS PLACED MOSTLY ON THE POTENTIAL OF TEMPERATURES NEARING
FROST CRITERIA/ 36F/ INTERIOR WEST SUNDAY NIGHT. DIFFICULTY OF
PINNING DOWN EXACT LOW TEMPS RESIDES WITH WINDS AND THE CLOUD COVER
PATTERN BETWEEN THE TROUGH ON MONDAY AND THE ONE ON TUESDAY.
FIRST...DRY AIR AND SUBSIDENCE WILL ERODE REMAINING CLOUDS FROM
SUNDAYS SHORTWAVE. SEVERAL MODELS ARE SHOWING AN ENHANCED LAYER OF
MOISTURE BETWEEN 800 AND 700MB MOVING INTO THE AREA LATE SUNDAY
NIGHT. THIS IS LIKELY RESIDUAL MOISTURE FROM DIURNAL CUMULUS ON
SUNDAY...AS IS NOTED WITH THE UPSTREAM SATELLITE IMAGES IN NORTHERN
MANITOBA...SO DO NOT THINK LOW CLOUDS WILL BE A FACTOR. AIR ABOVE
THE MID-LEVELS WILL BE QUITE DRY...WHICH IS ALSO NOTED ON IR/VIS
SATELLITE IMAGES FROM UPSTREAM. BEHIND A WEAK SFC RIDGE SUNDAY
EVENING...WINDS MAY END UP BEING THE LIMITING FACTOR AS THE PRESSURE
GRADIENT INCREASES WITH HIGH PRESSURE UNDER THE WESTERN RIDGE
BUILDING INTO THE REGION. THE LOW-LEVELS SHOULD BE ABLE TO DECOUPLE
ENOUGH...ESPECIALLY IN THE TYPICAL COLD SPOTS. ULTIMATELY...WILL
KEEP ONGOING FORECAST OF MID TO UPPER 30S WELL INLAND...AND LEAVE
PATCHY FROST OUT OF THE FORECAST FOR RIGHT NOW.
THE THIRD SHORTWAVE TROUGH IS PROGGED TO MOVE ACROSS THE CWA
THROUGHOUT THE DAY ON MONDAY. NOT MUCH IN THE WAY OF MOISTURE WITH
THIS SHORTWAVE EITHER. HOWEVER...AS THE INFLUENCE FROM THE TROUGH
APPROACHES THE SOUTH CENTRAL CWA...H8 WAA/MOISTURE TRANSPORT MAY
ASSIST WITH KICKING OFF SOME ISOLATED SHOWERS. LOW-LEVEL DRY AIR MAY
INHIBIT SHOWERS SOMEWHAT...SO WILL ONLY PUT A SLIGHT CHANCE IN THE
FORECAST FOR THE SOUTH-CENTRAL CWA. H8 TEMPS AROUND 7-8C SHOULD
YIELD HIGHS AROUND 70 FOR MOST LOCATIONS.
MONDAY NIGHT AND TUESDAY...THE DE-AMPLIFYING RIDGE FROM THE WESTERN
STATES WILL MOVE OVER UPPER MI MONDAY NIGHT...LEADING TO MOSTLY
CLEAR SKIES AND ANOTHER ROUND OF GOOD RADIATIONAL COOLING. THIS
TIME...DEW POINTS WILL BE MUCH HIGHER...SO MOST INLAND LOCATIONS
SHOULD STAY ABOVE 40. SUBSIDENCE FROM THE RIDGE WILL KEEP CONDITIONS
DRY THROUGH TUESDAY. H8 TEMPS FROM 10-12C WOULD RESULT IN MID 70S
FOR HIGHS ACROSS MOST OF THE CWA ON TUESDAY...WITH SLIGHTLY COOLER
TEMPS EAST IN REGIONS AFFECTED BY LAKE BREEZES FROM LAKES MICHIGAN
AND SUPERIOR.
TUESDAY NIGHT THROUGH SATURDAY...THE REMNANTS OF THE LOW CURRENTLY
OVER JAMES BAY WILL BE IN FAR NORTHERN QUEBEC BY TUESDAY NIGHT. A
SHORTWAVE TROUGH ROTATING AROUND THE BACK OF THE LOW IS PROGGED
TO MOVE THROUGH NORTHERN ONTARIO TUESDAY NIGHT INTO WEDNESDAY. THE
ECMWF HAS BEEN TRENDING FARTHER NORTH WITH THIS SYSTEM. MEANWHILE
THE GFS HAS BECOME THE MORE SOUTHERN SOLUTION. PREFER THE TREND OF
THE ECMWF AS THE WAVE WILL BE ATTEMPTING TO DIG INTO THE EASTERN
EDGE OF A NOW BUILDING WESTERN RIDGE. EXPECTATION IS THAT PRECIP
WILL STAY OUT OF THE AREA UNTIL LATE WEDNESDAY AS AN ASSOCIATED SFC
COLD FRONT STALLS OVER LAKE SUPERIOR...THOUGH THE FINAL LOCATION OF
THIS FEATURE IS STILL A LITTLE INCONSISTENT IN THE MODELS.
DRY AIR ABOVE THE LOWEST FEW KFT WILL ALLOW FOR DECENT MIXING ON
BOTH TUESDAY AND WEDNESDAY. LOWERED DAYTIME DEW POINTS ABOUT 5F FROM
PREVIOUS FORECAST FOR BOTH DAYS. THIS RESULTS IN MIN RH VALUES
AROUND 40 PERCENT BOTH DAYS. HOWEVER...FEELING IS THAT THE TREND
WILL BE TOWARD LOWER RH VALUES WITH PROCEEDING FORECASTS.
A DEEP TROUGH MOVING ONTO THE WEST COAST TUESDAY WILL THEN REACH THE
UPPER MS VALLEY BY LATE FRIDAY. THE INDUCED SFC LOW IS EXPECTED TO
BRING THE STALLED SFC BOUNDARY BACK NORTHWARD AS A WARM FRONT. HIGH
TEMPS DURING THIS TIME WILL LIKELY BE ABOVE NORMAL /AROUND 80/ DUE
TO SOUTHERLY FLOW SOUTH OF THE STALLED BOUNDARY...BUT AS NOTED
BEFORE...UNCERTAINTY STILL EXISTS IN THE FINAL LOCATION OF THE
BOUNDARY. WILL STICK WITH CONSENSUS OF MODEL THROUGHOUT THIS TIME
FRAME GIVEN DECENT AGREEMENT FOR THIS FAR OUT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 123 PM EDT SAT AUG 18 2012
INCOMING UPR DISTURBANCE/LO PRES TROF WL BRING THE THREAT OF -SHRA
AND PERHAPS A TS TO THE 3 SITES THIS AFTN...ESPECIALLY SAW. INCLUDED
EXPLICIT MENTION OF TS FOR A FEW HRS THIS AFTN ONLY AT SAW...WHERE
LESS EXPOSURE TO MODERATION OFF LK SUP AND LLVL CNVGC WL BE MOST
PRONOUNCED AND ABLE TO TAKE ADVANTAGE OF MARGINAL INSTABILITY. SINCE
THE LLVLS ARE SO DRY...VFR CONDITIONS SHOULD PREDOMINATE. THE SHRA
THREAT WL END EVERYWHERE BY 00Z WITH THE ARRIVAL OF DRIER AIR/ARPCH
OF SFC HI PRES. SOME FOG IS POSSIBLE LATE TNGT AT IWD...WHERE THE
LLVL DRYING WL BE LESS AGRESSIVE. AFTER ANY FOG BURNS OFF SOON AFTER
SUNRISE...SUN SHOULD FEATURE VFR CONDITIONS WITH LLVL ACYC FLOW
ASSOCIATED WITH HI PRES BLDG INTO THE AREA.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 359 PM EDT SAT AUG 18 2012
A GENERALLY WEAK PRES GRADIENT DOMINATING THE UPPER GREAT LAKES WILL
RESULT IN WINDS MOSTLY UNDER 20KT THRU THU. THE PRES GRADIENT WILL
BECOME A BIT SHARPER TUE NIGHT AS A LO PRES TROF MOVES ACROSS
CENTRAL ONTARIO...RESULTING IN WSW WINDS UP TO 25 KTS OVER PORTIONS
OF THE W AND NORTH CENTRAL.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TK
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
344 PM EDT SAT AUG 18 2012
.SYNOPSIS...
ISSUED AT 342 PM EDT SAT AUG 18 2012
A DEPARTING HIGH PRESSURE SYSTEM SHOULD CLEAR THE SKIES EARLY
TONIGHT. HOWEVER A COLD FRONT MOVING SOUTH THROUGH THE AREA SUNDAY
WILL BRING SOME SHOWERS AND ISOLATED THUNDERSTORMS TO NORTHERN
SECTIONS AFTER MIDNIGHT. AS THE FRONT MOVES THROUGH THE AREA
SUNDAY EXPECT SHOWERS AND ISOLATED THUNDERSTORMS. TEMPERATURES
WILL REMAIN BELOW NORMAL INTO TUESDAY BEFORE A SLOW WARMING TREND
SETS IN THAT WILL LAST NEXT WEEKEND.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 342 PM EDT SAT AUG 18 2012
THE PRIMARY ISSUE WITH THIS FORECAST IS CONVECTION AND THE
POTENTIAL FOR SHOWERS AND THUNDERSTORMS INTO MONDAY.
A WEAK CONVERGENCE BOUNDARY FROM NEAR MKG TO MBS THIS AFTERNOON IS
INTERACTING WITH THE LAKE BREEZE AND A WEAK MID LEVEL SHORTWAVE TO
CAUSE A CLUSTER OF SHOWERS AND ISOLATED THUNDERSTORMS THAT
CONTINUES TO MOVE EAST FROM NEWAYGO COUNTY INTO MONTCALM COUNTY.
THIS ACTIVITY IS MOVING VERY SLOWLY... ONLY 10 MPH AND SHOULD
DISSIPATE BY SUNSET OVER GRATIOT AND ISABELLA COUNTIES. AREAS NEAR
AND SOUTH OF INTERSTATE 96 SHOULD STAY DRY. DUE TO THE DRY SUB
CLOUD LAYER EXPECT SOME GUSTY WINDS WITH THE STORMS. WE HAVE SEEN
GUSTS TO AROUND 20 MPH SO FAR. A MESO-NET IN THE CITY OF NEWYGO HAD
A QUARTER INCH OF RAIN FROM THE STORMS THIS AFTERNOON SO FAR.
AS THE COLD FRONT DROPS SOUTH OVERNIGHT INTO SUNDAY THE SURFACE
PRESSURE GRADIENT IS WEAK. WITH THE SURFACE WATERS OF LAKE
MICHIGAN NEAR 22C AND AIR TEMPS EXPECTED TO FALL INTO THE 50S
INLAND AN LAND BREEZE WILL ONCE AGAIN SET UP. WITH THAT AND THE
FRONT MOVING SOUTH THE NAM12 SHOWS A MESO LOW FORMING THIS EVENING
NEAR TVC THE MOVING SOUTH TO LITTLE SABLE POINT BY MID MORNING
SUNDAY. THIS SHOULD FOCUS INSTABILITY NEAR THE LAKE SHORE AS IT
MOVES SOUTH OVERNIGHT. THERE IS ENOUGH INSTABILITY FOR
THUNDERSTORMS BASED ON BOTH RAP AND NAM SOUNDINGS. SO I INCREASED
POPS NORTH TONIGHT.
THIS BOUNDARY WILL SLOWLY MOVE SOUTH SUNDAY INTO SUNDAY EVENING.
THERE IS INSTABILITY BUT MARGINAL MOISTURE. EVEN SO GIVEN THE
CONVECTION THAT OCCURRED TODAY I BELIEVE SHOWERS ARE LIKELY NORTH
OF INTERSTATE 96 SUNDAY. WITH THE DRY SUB CLOUD LAYER EXPECT
GUSTY WINDS WITH THE SHOWERS AND THUNDERSTORMS. WITH THE COLD AIR
ALOFT EXPECT SMALL HAIL WITH THE STRONGER STORM TOO.
ONCE THE DRIER AIR BEHIND THE FRONT MOVES IN SUNDAY NIGHT SKIES
SHOULD CLEAR FROM NORTH TO SOUTH. WINDS WILL ONCE AGAIN BE LIGHT
SO ANOTHER LAKE BREEZE CONVERGENCE BAND OVER LAKE MICHIGAN IS
LIKELY TO FORM (SOUNDING REALLY SUPPORT THIS).
THERE IS STILL ENOUGH INSTABILITY WITH THE COLD AIR ALOFT FOR
AFTERNOON SHOWERS AND ISOLATED THUNDERSTORMS MONDAY. HOWEVER THE
MOISTURE IS ANEMIC. SO I WENT WITH ISOLATED SHOWERS /THUNDERSTORMS
FOR NOW.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 342 PM EDT SAT AUG 18 2012
WILL LEAVE TUESDAY DRY...BUT CAN NOT COMPLETELY RULE OUT A SHOWER AS
A SHORT WAVE CLEARS THE CWA. BEYOND THAT THE MID WEEK PERIOD LOOKS
QUIET AND PLEASANT AS LARGE HIGH PRESSURE SLIDES IN. THE HIGH
BECOMES BLOCKED BY AN UPPER LOW OVER THE CANADIAN MARITIME...SO
COMFORTABLE WEATHER SHOULD PREVAIL FOR A FEW DAYS. THE RIDGE
FINALLY MOVES EAST LATE IN THE WEEK WHICH ALLOWS A NORTHERN STREAM
SHORT WAVE TO APPROACH. WILL START POPS FRIDAY NIGHT IN THE WEST...
THEN SPREAD OVER ENTIRE CWA SATURDAY.
AS FOR TEMPS...WE SHOULD SEE A SLIGHT MODERATING TREND...BUT STAYING
NEAR NORMAL MUCH OF THE TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 109 PM EDT SAT AUG 18 2012
VFR CONDITIONS WILL CONTINUE THROUGH THE EVENING HOURS. SOME
PATCHY FOG WILL DEVELOP TOWARD DAYBREAK SUNDAY. THERE COULD BE
SOME IFR CONDITIONS...BUT THIS SHOULD NOT LAST LONG...NO MORE THAN
A COUPLE HOURS AT ANY ONE LOCATION.
AN ISOLATED THUNDERSTORM OR TWO MAY BE POSSIBLE AFTER 15Z SUNDAY
ALONG AND NORTH OF I-96. HAVE NOT MENTION THESE IN THE TAFS
HOWEVER DUE TO THEIR ISOLATED NATURE.
&&
.MARINE...
ISSUED AT 342 PM EDT SAT AUG 18 2012
WINDS WILL FOR THE MOST PART BE LESS THAN 15 KNOTS THROUGH MONDAY.
THUS I SEE NO NEED FOR A SMALL CRAFT ADVISORY AT THIS TIME. EVEN
SO THERE IS UNSEASONABLY COOL AIR IN PLACE AND LAKE MICHIGAN IS
STILL WARM RELATIVE TO THE AIR OVER IT... SO WITH THE CONVECTION
EXPECTED LATER TONIGHT AND SUNDAY EXPECT ISOLATED WATER SPOUTS
WITH THE STRONG SHOWERS AND THUNDERSTORMS. I ADDED THEM TO THE
GRIDS INTO SUNDAY AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 342 PM EDT SAT AUG 18 2012
WHILE THERE WILL BE SHOWERS AROUND INTO MONDAY I DO NOT EXPECT ANY
WIDESPREAD HEAVY RAINFALL. THUS NO BIG HYDRO ISSUES ARE FORESEEN AT
THIS TIME.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...JK
AVIATION...JK
HYDROLOGY...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
739 AM EDT SAT AUG 18 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EDT SAT AUG 18 2012
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A DEEP TROF DOMINATING
ROUGHLY THE E HALF OF THE CONUS. TROF IS ANCHORED BY A MID/UPPER
LEVEL LOW CENTERED OVER JAMES BAY. A NUMBER OF SHORTWAVES ARE
ROTATING THRU THE TROF THOUGH NONE ARE ESPECIALLY STRONG. MOST
NOTABLE WAVES ARE TRACKING SE THRU MN AND THE DAKOTAS...BUT THE WAVE
OF INTEREST FOR TODAY IS DROPPING THRU NRN ONTARIO. CANADIAN RADARS
HAVE BEEN SHOWING SCT SHRA STREAKING SE ACROSS NE LAKE SUPERIOR WITH
MAIN BAND OF SHRA SINKING S TOWARD THE MN ARROWHEAD AND ISLE ROYALE.
FCST THINKING FOR TODAY HASN`T CHANGED MUCH FROM PREVIOUS SHIFTS.
SHORTWAVE WILL DROP INTO THE UPPER LAKES TODAY WITH ASSOCIATED SFC
COLD FRONT MOVING THRU THE AREA. WITH CYCLONIC FLOW...APPROACHING
SHORTWAVE/COLD POCKET ALOFT...COLD FRONT ARRIVING DURING HEATING
CYCLE AND MLCAPE INCREASING TO BTWN 200 AND 500J/KG...IT STILL LOOKS
LIKE A GOOD SETUP FOR SCT/NMRS SHRA TODAY...ESPECIALLY SINCE SHRA
ARE ALREADY OCCURRING UPSTREAM DURING THE PERIOD OF THE DIURNAL MIN.
TIMING OF COLD FRONT INTO THE SRN FCST AREA DURING THE LATER AFTN
SHOULD FAVOR THAT AREA FOR THE GREATEST SHRA COVERAGE. CAN`T RULE
OUT SOME THUNDER AS WELL...PARTICULARLY SINCE A FEW LIGHTNING
STRIKES WERE DETECTED UPSTREAM IN ONTARIO LAST EVENING. AGAIN...THE
SRN PORTIONS OF THE FCST AREA WILL BE FAVORED. LOW FREEZING/WET BULB
ZERO LEVELS SUPPORT POTENTIAL OF SMALL HAIL WITH ANY STORMS...
ESPECIALLY IF THERE IS ENOUGH HEATING THRU THE MORNING HRS TO HELP
BUILD INSTABILITY A LITTLE HIGHER THAN CURRENTLY PROGGED.
ALTHOUGH WAVES ARE SUBSIDING ON LAKE SUPERIOR AFTER A COUPLE OF
ROUGH DAYS...WAVES ARE STILL HIGH ENOUGH TO RESULT IN A MODERATE
RISK OF RIP CURRENTS ALONG THE BEACHES OF ALGER COUNTY THRU EARLY
AFTERNOON.
SIGNIFICANT COLUMN DRYING OCCURS TONIGHT BEHIND SHORTWAVE...MOST
NOTABLY WITH THE GFS. THIS WILL WORK TO MINIMIZE LAKE EFFECT -SHRA
POTENTIAL AS 850MB TEMPS BECOME MARGINALLY LOW ENOUGH OVER THE ERN
LAKE (4C) BY 12Z SUN. GIVEN THE DRYING...WILL NOT INCLUDE ANY PCPN
MENTION OTHER THAN LINGERING -SHRA SCNTRL. TO THE W...DEGREE OF
DRYING AND WARMER 850MB TEMPS SUGGESTS LITTLE/NO LAKE CLOUD...AND
WITH WINDS DIMINISHING UNDER DRYING COLUMN (PRECIPITABLE WATER
40-55CT OF NORMAL)...IT SHOULD BE A CHILLY NIGHT OVER THE INTERIOR
W. A FEW UPPER 30S ARE POSSIBLE IN THE TRADITIONAL COLD SPOTS.
TYPICAL FOR COOL NIGHTS AT THIS TIME OF YEAR...SOME GROUND FOG WILL
ALSO BE POSSIBLE IN LOW-LYING AREAS AROUND
RIVERS/STREAMS/LAKES/SWAMPS OVER THE INTERIOR W HALF...ESPECIALLY
WHERE RAINFALL OCCURS TODAY.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 500 AM EDT SAT AUG 18 2012
SUN...MODELS HINT AT A WEAK DISTURBANCE ROTATING DOWN FM CLOSED LOW
NEAR JAMES BAY...BUT VERY DRY LOW LVLS AND WEAK DYNAMIC FORCING
SHOULD ALLOW FOR MAINLY DRY CONDITIONS ACROSS CWA. FCST H85 TEMPS FM
6C OVER THE E TO 8C OVER THE W IN LIGHT NRLY FLOW WILL SUPPORT HI
TEMPS FM MID 60S NEAR LAKE SUPERIOR TO LOWER 70S SCNTRL.
SUN NIGHT...ALTHOUGH THERE MAY BE MORE SCT MID CLDS ASSOCIATED WITH
ANOTHER DISTURBANCE APPROACHING IN NW FLOW ALF...LACK OF SIGNIFICANT
DYNAMIC SUPPORT AND OVERALL DRYNESS OF THE LLVLS SHOULD PREVENT ANY
PCPN. WITH LGT WINDS ESPECIALLY IN THE EVENING CLOSER TO SFC HI PRES
SINKING TOWARD THE LOWER GREAT LAKES...TEMPS COULD FALL INTO THE MID
TO UPPER 30S OVER SOME WRN INTERIOR COLD SPOTS WITH LOWER 40S
ELSEWHERE INLAND. DID NOT MENTION ANY PATCHY FROST FOR NOW BUT THIS
COULD BE A POSSIBILITY IF MODELS KEEP SFC RDG OVER AREA LONGER...
ALLOWING FOR LONGER PD OF GOOD RADIATIONAL COOLING. TEMPS WILL STAY
WARMER NEAR THE GREAT LAKES...IN THE UPPER 40S TO MID 50S.
MON...12Z NAM/GFS STILL GENERATE SOME LIGHT PCPN ASSOCIATED WITH
PASSAGE OF NEXT NW SHORTWAVE MOVING DOWN BACKSIDE OF MID-LVL TROF.
HOWEVER...LACK OF ANY SIGNIFICANT MOISTENING OR DEEP LYR Q-VECT CONV
AS WELL AS MARGINAL INSTABILITY (< 100 J/KG) SHOULD YIELD ONLY
PARTLY CLOUDY SKIES AND DRY CONDITIONS PER CANADIAN/ECMWF MODELS.
WITH H85 TEMPS FM 6-8C UNDER CONTINUED LIGHT NRLY FLOW...EXPECT HI
TEMPS FM MID 60S ALONG LAKE SUPERIOR TO LOWER 70S SOUTH CENTRAL.
TUESDAY THROUGH FRIDAY...LATEST 00Z RUN OF ECMWF TRENDING FARTHER
NORTH AND NOT AS DEEP WITH NEXT NW FLOW SHORTWAVE TUE NIGHT AND WED
PER CANADIAN MODEL. IT LOOKS LIKE BEST FORCING WILL STAY WELL NORTH
SO HAVE TRIMMED BACK POPS TO SLIGHT CHC TUE NIGHT INTO WEDNESDAY
NIGHT. THE GLOBAL GEM AND TO LESSER EXTENT THE ECMWF SHOW A
SHORTWAVE/VORT MAX APPROACHING FROM THE NRN PLAINS LATE THU.
INCREASING WAA IN RESPONSE TO THIS SHORTWAVE AS NOTED ON ECMWF COULD
TRIGGER SOME ISOLD SHRA/TSRA LATE THU. CHC POPS FOR CONVECTION
WARRANTED BY FRIDAY AS ECMWF AND CANADIAN MODEL ADVERTISE INCREASING
Q-VECT CONV...WAA AND DIFLUENT MID-LVL FLOW AHEAD OF SHORTWAVE
MOVING IN FM THE NRN PLAINS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 738 AM EDT SAT AUG 18 2012
UPPER LEVEL DISTURBANCE AND ASSOCIATED COLD FRONT APPROACHING FROM
ONTARIO WILL BRING INCREASING CLOUDS AND POTENTIAL FOR -SHRA AT
KIWD/KCMX/KSAW TODAY. AT THIS TIME...IT APPEARS CONDITIONS WILL
REMAIN VFR PER UPSTREAM OBS. HOWEVER...AS SOME INSTABILITY BUILDS
WITH DAYTIME HEATING...-SHRA MAY BECOME HEAVIER...LEADING TO MVFR
CONDITIONS...ESPECIALLY AT KSAW. IN ADDITION...THERE IS A SMALL RISK
OF TSRA...MAINLY AT KSAW DUE TO EXPECTED BETTER DAYTIME HEATING THIS
MORNING. WITH EXPECTED LIMITED COVERAGE OF TSRA...DID NOT INCLUDE
MENTION IN FCST YET. RAINFALL TODAY MAY LEAD TO FOG TONIGHT...MAINLY AT
KIWD/KSAW. WILL NEED TO REASSESS THIS POTENTIAL IN LATER FCSTS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 500 AM EDT SAT AUG 18 2012
A GENERALLY WEAK PRES GRADIENT DOMINATING THE UPPER GREAT LAKES WILL
RESULT IN WINDS MOSTLY UNDER 20KT THRU THE MIDDLE OF THE UPCOMING
WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...VOSS
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
501 AM EDT SAT AUG 18 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EDT SAT AUG 18 2012
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A DEEP TROF DOMINATING
ROUGHLY THE E HALF OF THE CONUS. TROF IS ANCHORED BY A MID/UPPER
LEVEL LOW CENTERED OVER JAMES BAY. A NUMBER OF SHORTWAVES ARE
ROTATING THRU THE TROF THOUGH NONE ARE ESPECIALLY STRONG. MOST
NOTABLE WAVES ARE TRACKING SE THRU MN AND THE DAKOTAS...BUT THE WAVE
OF INTEREST FOR TODAY IS DROPPING THRU NRN ONTARIO. CANADIAN RADARS
HAVE BEEN SHOWING SCT SHRA STREAKING SE ACROSS NE LAKE SUPERIOR WITH
MAIN BAND OF SHRA SINKING S TOWARD THE MN ARROWHEAD AND ISLE ROYALE.
FCST THINKING FOR TODAY HASN`T CHANGED MUCH FROM PREVIOUS SHIFTS.
SHORTWAVE WILL DROP INTO THE UPPER LAKES TODAY WITH ASSOCIATED SFC
COLD FRONT MOVING THRU THE AREA. WITH CYCLONIC FLOW...APPROACHING
SHORTWAVE/COLD POCKET ALOFT...COLD FRONT ARRIVING DURING HEATING
CYCLE AND MLCAPE INCREASING TO BTWN 200 AND 500J/KG...IT STILL LOOKS
LIKE A GOOD SETUP FOR SCT/NMRS SHRA TODAY...ESPECIALLY SINCE SHRA
ARE ALREADY OCCURRING UPSTREAM DURING THE PERIOD OF THE DIURNAL MIN.
TIMING OF COLD FRONT INTO THE SRN FCST AREA DURING THE LATER AFTN
SHOULD FAVOR THAT AREA FOR THE GREATEST SHRA COVERAGE. CAN`T RULE
OUT SOME THUNDER AS WELL...PARTICULARLY SINCE A FEW LIGHTNING
STRIKES WERE DETECTED UPSTREAM IN ONTARIO LAST EVENING. AGAIN...THE
SRN PORTIONS OF THE FCST AREA WILL BE FAVORED. LOW FREEZING/WET BULB
ZERO LEVELS SUPPORT POTENTIAL OF SMALL HAIL WITH ANY STORMS...
ESPECIALLY IF THERE IS ENOUGH HEATING THRU THE MORNING HRS TO HELP
BUILD INSTABILITY A LITTLE HIGHER THAN CURRENTLY PROGGED.
ALTHOUGH WAVES ARE SUBSIDING ON LAKE SUPERIOR AFTER A COUPLE OF
ROUGH DAYS...WAVES ARE STILL HIGH ENOUGH TO RESULT IN A MODERATE
RISK OF RIP CURRENTS ALONG THE BEACHES OF ALGER COUNTY THRU EARLY
AFTERNOON.
SIGNIFICANT COLUMN DRYING OCCURS TONIGHT BEHIND SHORTWAVE...MOST
NOTABLY WITH THE GFS. THIS WILL WORK TO MINIMIZE LAKE EFFECT -SHRA
POTENTIAL AS 850MB TEMPS BECOME MARGINALLY LOW ENOUGH OVER THE ERN
LAKE (4C) BY 12Z SUN. GIVEN THE DRYING...WILL NOT INCLUDE ANY PCPN
MENTION OTHER THAN LINGERING -SHRA SCNTRL. TO THE W...DEGREE OF
DRYING AND WARMER 850MB TEMPS SUGGESTS LITTLE/NO LAKE CLOUD...AND
WITH WINDS DIMINISHING UNDER DRYING COLUMN (PRECIPITABLE WATER
40-55CT OF NORMAL)...IT SHOULD BE A CHILLY NIGHT OVER THE INTERIOR
W. A FEW UPPER 30S ARE POSSIBLE IN THE TRADITIONAL COLD SPOTS.
TYPICAL FOR COOL NIGHTS AT THIS TIME OF YEAR...SOME GROUND FOG WILL
ALSO BE POSSIBLE IN LOW-LYING AREAS AROUND
RIVERS/STREAMS/LAKES/SWAMPS OVER THE INTERIOR W HALF...ESPECIALLY
WHERE RAINFALL OCCURS TODAY.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 500 AM EDT SAT AUG 18 2012
SUN...MODELS HINT AT A WEAK DISTURBANCE ROTATING DOWN FM CLOSED LOW
NEAR JAMES BAY...BUT VERY DRY LOW LVLS AND WEAK DYNAMIC FORCING
SHOULD ALLOW FOR MAINLY DRY CONDITIONS ACROSS CWA. FCST H85 TEMPS FM
6C OVER THE E TO 8C OVER THE W IN LIGHT NRLY FLOW WILL SUPPORT HI
TEMPS FM MID 60S NEAR LAKE SUPERIOR TO LOWER 70S SCNTRL.
SUN NIGHT...ALTHOUGH THERE MAY BE MORE SCT MID CLDS ASSOCIATED WITH
ANOTHER DISTURBANCE APPROACHING IN NW FLOW ALF...LACK OF SIGNIFICANT
DYNAMIC SUPPORT AND OVERALL DRYNESS OF THE LLVLS SHOULD PREVENT ANY
PCPN. WITH LGT WINDS ESPECIALLY IN THE EVENING CLOSER TO SFC HI PRES
SINKING TOWARD THE LOWER GREAT LAKES...TEMPS COULD FALL INTO THE MID
TO UPPER 30S OVER SOME WRN INTERIOR COLD SPOTS WITH LOWER 40S
ELSEWHERE INLAND. DID NOT MENTION ANY PATCHY FROST FOR NOW BUT THIS
COULD BE A POSSIBILITY IF MODELS KEEP SFC RDG OVER AREA LONGER...
ALLOWING FOR LONGER PD OF GOOD RADIATIONAL COOLING. TEMPS WILL STAY
WARMER NEAR THE GREAT LAKES...IN THE UPPER 40S TO MID 50S.
MON...12Z NAM/GFS STILL GENERATE SOME LIGHT PCPN ASSOCIATED WITH
PASSAGE OF NEXT NW SHORTWAVE MOVING DOWN BACKSIDE OF MID-LVL TROF.
HOWEVER...LACK OF ANY SIGNIFICANT MOISTENING OR DEEP LYR Q-VECT CONV
AS WELL AS MARGINAL INSTABILITY (< 100 J/KG) SHOULD YIELD ONLY
PARTLY CLOUDY SKIES AND DRY CONDITIONS PER CANADIAN/ECMWF MODELS.
WITH H85 TEMPS FM 6-8C UNDER CONTINUED LIGHT NRLY FLOW...EXPECT HI
TEMPS FM MID 60S ALONG LAKE SUPERIOR TO LOWER 70S SOUTH CENTRAL.
TUESDAY THROUGH FRIDAY...LATEST 00Z RUN OF ECMWF TRENDING FARTHER
NORTH AND NOT AS DEEP WITH NEXT NW FLOW SHORTWAVE TUE NIGHT AND WED
PER CANADIAN MODEL. IT LOOKS LIKE BEST FORCING WILL STAY WELL NORTH
SO HAVE TRIMMED BACK POPS TO SLIGHT CHC TUE NIGHT INTO WEDNESDAY
NIGHT. THE GLOBAL GEM AND TO LESSER EXTENT THE ECMWF SHOW A
SHORTWAVE/VORT MAX APPROACHING FROM THE NRN PLAINS LATE THU.
INCREASING WAA IN RESPONSE TO THIS SHORTWAVE AS NOTED ON ECMWF COULD
TRIGGER SOME ISOLD SHRA/TSRA LATE THU. CHC POPS FOR CONVECTION
WARRANTED BY FRIDAY AS ECMWF AND CANADIAN MODEL ADVERTISE INCREASING
Q-VECT CONV...WAA AND DIFLUENT MID-LVL FLOW AHEAD OF SHORTWAVE
MOVING IN FM THE NRN PLAINS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 138 AM EDT SAT AUG 18 2012
CLOUDS EXPECTED TO INCREASE OVERNIGHT AS UPPER DISTURBANCE
APPROACHES FROM ONTARIO. EXPECT SCT SHRA INTO CMX BY DAYBREAK THIS
MORNING AND AT SAW BY LATER THIS MORNING. BEST CHANCE FOR ANY TSRA
WOULD BE AT SAW THIS AFTERNOON...BUT KEPT MENTION OUT OF TAF AS TSRA
COVERAGE WILL BE ISOLD. CONTINUE TO KEEP SHRA OUT OF IWD AS ONLY
ISOLD COVERAGE IS EXPECTED AND DURATION WILL BE FAIRLY BRIEF.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 500 AM EDT SAT AUG 18 2012
A GENERALLY WEAK PRES GRADIENT DOMINATING THE UPPER GREAT LAKES WILL
RESULT IN WINDS MOSTLY UNDER 20KT THRU THE MIDDLE OF THE UPCOMING
WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...VOSS
AVIATION...JLA
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
316 PM CDT SAT AUG 18 2012
.DISCUSSION...
SCATTERED SHOWERS CONTINUE TO SLIDE SOUTHEAST AS FORCING FOR
ASCENT FROM A MID LEVEL SHORTWAVE CONTINUES TO MOVE SOUTHEAST THRU
THE FORECAST AREA. THERE IS ANOTHER AREA OF SHOWERS IN A BAND TO
THE NORTHEAST OF THE CWA WHICH SEEMS TO LINE UP WELL WITH A NARROW
BAND OF MID LEVEL FRONTOGENESIS ON NOSE OF THETA-E AXIS. THIS
IS FORECAST TO CONTINUE SOUTHEAST THRU THE LATE AFTERNOON AND
EVENING HOURS SO WL CONTINUE TO INCLUDE A SMALL MENTION OF POPS IN
OUR EASTERN COUNTIES FOR THIS ACTIVITY AS WELL. IN
ADDITION...THERE IS A POTENTIAL FOR FOG DEVELOPMENT OVERNIGHT WITH
CLEARING SKIES. SFC WIND BECOMES LIGHT AND VARIABLE AS HIGH
PRESSURE MOVES OVER AREAS THAT SAW SOME PRECIPITATION TODAY.
LATEST HRRR ALSO SHOWING AREA OF REDUCED VISIBILITIES...ESPECIALLY
IN OUR NORTH SO WL GO AHEAD AND MENTION SOME PATCHY FOG OVERNIGHT.
EXPECTING LOWS TO FALL INTO THE UPPER 40S TO LOWER 50S WHICH
WILL BE CLOSE BUT SLIGHTLY ABOVE RECORDS.
SUNDAY CONTINUES TO LOOK MOSTLY DRY AS HIGH PRESSURE SLIDES EAST OF
THE AREA. MODELS CONTINUE TO INDICATE SOME LIGHT QPF IN OUR EASTERN
COUNTIES ASSOCIATED WITH EXITING UPPER LEVEL SHORTWAVE ENERGY. MAY
HAVE SOME ISOLATED SHOWERS OVER IOWA COUNTIES IN THE AFTERNOON
ONCE CU FIELD DEVELOPS. WILL THROW IN A SLIGHT CHANCE POP IN OUR
FAR NERN COUNTIES FOR SUNDAY AFTERNOON AND MENTION ISOLATED
THUNDER AS SOME INSTABILITY IS PRESENT.
AREA REMAINS IN NORTHWESTERLY FLOW FOR EARLY IN THE SCHOOL/WORK
WEEK. THE WEATHER SHOULD REMAIN FAIRLY QUIET WITH WARM SOUTHERLY
FLOW BRINGING A SLIGHT INCREASE IN LOW LEVEL MOISTURE TO THE
AREA.
IN THE EXTENDED...MID LEVEL FLOW WILL BECOME MORE ZONAL BY MID
WEEK AS WEAKENING UPPER LEVEL RIDGE FLATTENS OVER THE NATIONS MID
SECTION. A POTENT SHORTWAVE MOVING INTO THE NORTHERN PLAINS BY
LATE IN THE WEEK WILL DRIVE A COOL FRONT THRU THE CENTRAL PLAINS.
AHEAD OF THIS BOUNDARY...LOW LEVEL WARM AIR AND MOIST ADVECTION
COULD LEAD TO A SCATTERED CHANCE OF SHOWERS AND THUNDERSTORMS
THURSDAY. SEVERE THREAT WOULD LIKELY REMAIN FAR TO OUR
NORTH...CLOSER TO POTENT SHORTWAVE ENERGY.
&&
.AVIATION...
18Z TAFS FOR KOMA...KLNK AND KOFK.
SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO AFFECT KOMA
AND KLNK THIS AFTERNOON. KEPT CIGS VFR WITH MOST CIGS IN THE FL060
TO FL100 LEVEL. SFC WINDS HAVE BEEN VARIABLE WITH OUTFLOW AND
NORTHWEST WINDS ASSOCIATED WITH PRECIPITATION AND GUSTY WINDS
FROM THE SOUTHEAST BEHIND PRECIPITATION AREA. SOME OF THE SHORT
TERM MODELS ARE HOLDING ON TO CIGS OVERNIGHT...THOUGHT TREND
SHOULD BE FOR SCATTERING OUT ALTHOUGH THERE COULD BE SOME PATCHY
FOG.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1225 AM CDT SAT AUG 18 2012
.AVIATION...06Z TAF. MAIN CONCERN WILL BE TIMING THUNDERSTORMS
THROUGH THE KGRI TERMINAL AREA. STILL LOOKS LIKE THE BEST CHANCE
WILL BE DURING THE MORNING HOURS. EARLY THIS MORNING THERE HAS
BEEN SOME MID LEVEL CLOUDS DEVELOPING TO THE SOUTH OF KGRI. THEY
SHOULD STAY MAINLY SOUTH OF THE TERMINAL...BUT MAY SNEAK INTO THE
AREA LATER. SOME MID AND HIGH CLOUDS WILL LINGER AFTER THE
THUNDERSTORMS FOR A TIME...BUT GRADUALLY MOVE OUT. A WEAK COLD
FRONT WILL MOVE THROUGH AND TURN WINDS TO THE NORTHWEST DURING
THE LATE MORNING.
&&
.PREV DISCUSSION... /ISSUED 408 PM CDT FRI AUG 17 2012/
SHORT TERM...THROUGH SATURDAY DAYTIME. PRIMARY ISSUE DURING THE
NEXT 24 HOURS IS TRYING TO PIN DOWN HIGH WIDESPREAD
SHOWER/THUNDERSTORM ACTIVITY WILL BE LATE TONIGHT INTO THE DAYTIME
SATURDAY...AND THE RESULTANT EFFECTS ON HIGH TEMPERATURES.
19Z OBJECTIVE SURFACE ANALYSIS REVEALS AN INCREDIBLY PLEASANT
AFTERNOON ACROSS THE CWA WITH VERY LIGHT BREEZES...THANKS TO A
1020MB RIDGE AXIS PARKED DIRECTLY OVER THE AREA AND EXTENDING
NORTHEAST INTO MN. VISIBLE SATELLITE CONFIRMS NEARLY CLOUD-FREE
SKIES ACROSS THE NORTHEAST 1/2 OF THE CWA...WHILE IN THE
SOUTHWEST...WHAT WAS A FAIRLY SOLID MID LEVEL CLOUD DECK A FEW
HOURS AGO HAS STEADILY ERODED/SCATTERED OUT QUITE A BIT. WATER
VAPOR SATELLITE IMAGERY ALONG WITH SHORT TERM MODEL DATA DEPICTS
THE CWA UNDER SEASONABLY STRONG NORTHWEST FLOW ALOFT...SANDWICHED
BETWEEN A LARGE SCALE TROUGH OVER THE NORTHEAST CONUS WHICH IS
ANCHORED BY A VIGOROUS VORT MAX OVER EASTERN QUEBEC...AND A BROAD
RIDGE CENTERED FROM THE INTERMOUNTAIN WEST TO SOUTH TX. THE QUICK
MOVING SHORTWAVE/SPEED MAX THAT WILL BRING PRECIP CHANCES LATE
TONIGHT INTO SATURDAY IS CURRENTLY EVIDENT DROPPING SOUTHEAST NEAR
THE MT/ND/CANADA BORDER. TEMPS THIS AFTERNOON ARE VERY MUCH ON
TRACK WITH PREVIOUS FORECAST HIGHS...AND MAY ACTUALLY EXCEED THEM
SLIGHTLY IN SOME AREAS AS A FEW POTS ARE MAKING A RUN AT REACHING
80. AS SUGGESTED IN THE EARLIER UPDATE DISCUSSION...LIMITED MIXING
INTO VERY DRY AIR ALOFT HAS ALLOWED SURFACE DEWPOINTS TO FALL INTO
THE UPPER 30S IN SOME AREAS...ALTHOUGH LOW 40S ARE PREVALENT.
FOR THIS EVENING/TONIGHT...THE MOST SIGNIFICANT CHANGE WAS TO
COMPLETELY REMOVE ALL MENTION OF SHOWERS/STORMS BEFORE 06Z...AS
MOISTURE RETURN AND RESULTANT ELEVATED INSTABILITY NOW APPEARS
CONSIDERABLY MORE DELAYED THAN IT DID 24 HOURS AGO. THAT BEING
SAID...LATEST RAP-BASED HOURLY MESOANALYSIS INDICATED THE
PRESENCE OF UP TO 500 J/KG MUCAPE CURRENTLY SITTING ACROSS
SOUTHWEST ZONES ALONG THE LEADING EDGE OF MOISTURE RETURN AROUND
700MB. HOWEVER THE 12Z NAM WOULD SUGGEST THIS MUCAPE IS ACTUALLY
MORE MEAGER AND MORE CAPPED THAN THE RAP SUGGESTS...AND GIVEN THE
LIMITED FORCING AND THE FACT THAT A NUMBER OF DETERMINISTIC AND
HIGH RES MODELS SUCH AS THE 12Z 4KM WRF-NMM DO NOT INITIATE
CONVECTION IN THIS AREA THROUGH THIS EVENING...HAVE REMOVED THE
SLIGHT POPS. FOR THE LATE NIGHT 06Z-12Z PERIOD...DECIDED TO BREAK
THE POP/WX GRIDS INTO 3-HOUR BLOCKS...WITH THE PRIMARY FOCUS
SQUARELY ON THE VERY LATE NIGHT/EARLY MORNING HOURS POST-09Z. FOR
THE 06Z-09Z PERIOD...ONLY HAVE SLIGHT POPS CREEPING INTO A FEW FAR
SOUTHWEST COUNTIES. THEN AFTER 09Z...BRING IN 20-30 PERCENT
SHOWER/ISOLATED STORM CHANCES FOR ALL BUT ROUGHLY THE EASTERN 1/4
OF THE CWA. AS THE NIGHT WEARS ON...THE AFOREMENTIONED NORTHWEST
FLOW SHORTWAVE WILL REACH THE SD/NORTHERN NEB BORDER AREA...WHILE
OUT AHEAD OF IT...THETA-E ADVECTION MAINLY IN THE 850-700MB LAYER
WILL BE ON THE INCREASE...AS THE EASTERN EDGE OF A MODEST 850MB
LOW LEVEL JET VEERS INTO THE AREA. INTERESTINGLY...THE NEWLY
ARRIVED 18Z NAM KEEPS MOST ALL OF THIS ACTIVITY OUTSIDE THE CWA
UNTIL AFTER SUNRISE...BUT FEEL AT LEAST 20-30 POPS ARE WARRANTED
BASED ON THE 4KM WRF-NMM AND NSSL 4KM-WRF DEPICTION OF ONE BATCH
OF SHOWERS/FEW STORMS SLIDING INTO THE CWA FROM THE
NORTHWEST...WHILE ANOTHER POTENTIALLY SEPARATE AREA DEVELOPS OVER
THE SOUTHWESTERN CWA MAINLY IN KS. ALTHOUGH NOT ANTICIPATING A
SEVERE WEATHER THREAT THROUGH SUNRISE WITH MUCAPE LIKELY REMAINING
NO MORE THAN A FEW HUNDRED J/KG...SUPPOSE A FEW STRONGER CORES
WITH SMALL HAIL CANNOT BE RULED OUT GIVEN STRONG DEEP LAYER SHEAR
ON THE ORDER OF 50+ KNOTS. TEMP WISE TONIGHT...GIVEN THE SLOWER
ONSET OF CLOUDS AND STORM CHANCES...AND WITH WINDS REMAINING LIGHT
AS THE RIDGE AXIS SLOWLY DEPARTS...NUDGED DOWN LOWS TONIGHT 2-3
DEGREES IN MOST AREAS...WITH MUCH OF THE CWA AIMED INTO THE 50-53
RANGE...AND EVEN COOLER MID-UPPER 40S IN THE FAR EAST...BUT NOT
RECORD-BREAKING TERRITORY.
TURNING TO THE DAYTIME PERIOD 12Z-00Z...SPLIT THE DAY INTO 6-HOUR
BLOCKS FOR POPS/WEATHER...WITH THE OVERALL BEST RAIN CHANCES FOCUSED
DURING THE MORNING. ALOFT...THE COMPACT BUT FAIRLY VIGOROUS
NORTHWEST FLOW WAVE WILL DIVE SOUTHWARD ACROSS THE EASTERN HALF OF
NEBRASKA TOWARD NORTHEAST KANSAS DURING THE DAY...ACCOMPANIED BY
AN ASSOCIATED UPPER LEVEL JET STREAK. ALTHOUGH IT WILL NOT BE AN
ALL-DAY RAIN OUT BY ANY MEANS...THE CONSENSUS OF VARIOUS MODELS
INCLUDING THE 12Z 4KM WRF-NMM REFLECTIVITY SHOWS A DECENT CHANCE
FOR AT LEAST SCATTERED SHOWERS/A FEW STORMS SPREADING SOUTHEAST
ACROSS THE CWA DURING THE DAY...POSSIBLY IN TWO SEPARATE ROUNDS
WITH ONE ROUND DURING THE MORNING...FOLLOWED BY MORE HIT AND MISS
ACTIVITY DURING THE AFTERNOON DIRECTLY UNDER THE SHORTWAVE AXIS.
WITH THE OVERALL BEST COVERAGE EXPECTED DURING THE MORNING
HOURS...INCREASED POPS TO 50S ACROSS ROUGHLY THE NORTHWEST 1/2 OF
THE CWA...BUT KEPT THEM BELOW LIKELY TERRITORY FOR NOW. DURING THE
AFTERNOON...WENT LOWER WITH POPS BUT KEPT AT LEAST 20-30 PERCENT
CHANCES AND HIGHEST ACROSS THE EASTERN 1/2. AS FOR SEVERE
CHANCES...WITH BOTH ELEVATED AND NEAR SURFACE-BASED PARCELS NOT
EXPECTED TO AVERAGE MORE THAN 500 J/KG MOST AREAS...WHICH CAME IN
LOWER ON THE 18Z NAM THAN ITS 12Z RUN...NOT EXPECTING SEVERE
STORMS TO BE A BIG ISSUE. HOWEVER...GIVEN THE VIGOROUS WAVE AND
CONTINUED SEASONABLY STRONG DEEP LAYER SHEAR...AT LEAST A FEW
STRONG TO MARGINALLY SEVERE STORMS MAINLY WITH HAIL POTENTIAL TO
AROUND QUARTER SIZE ARE NOT OUT OF THE QUESTION...ESPECIALLY IN
KANSAS ZONES...AND AGREE WITH SPC ON HIGHLIGHTING THESE SOUTHERN
ZONES FOR 5 PERCENT SEVERE PROBS ON THE DAY 2 OUTLOOK. AS FOR RAIN
AMOUNTS SATURDAY...WOULD EXPECT THAT MOST PLACES WILL AVERAGE
UNDER ONE-QUARTER INCH...SO NOT A MAJOR BOOST TO DROUGHT RELIEF BY
ANY MEANS. TEMP-WISE...IT WILL BE A TRICKY BATTLE BETWEEN
WIDESPREAD CLOUDS/SCATTERED RAIN FOR THE MAJORITY OF THE DAY...BUT
POTENTIAL FOR DECENT AFTERNOON CLEARING ESPECIALLY NORTHWEST.
OVERALL MADE NO BIG CHANGES...BUT RAISED WESTERN ZONES A FEW
DEGREES...ESPECIALLY UP AROUND ORD. HAVE MOST OF THE CWA TOPPING
OUT IN THE 76-81 RANGE.
LONG TERM...STARTING SATURDAY EVENING. GUIDANCE SUGGESTS
NORTHWESTERLY UPPER LEVEL FLOW WILL PERSIST OVER THE CENTRAL
PLAINS THROUGH MUCH OF THE EXTENDED FORECAST PERIOD AS UPPER LEVEL
RIDGING REMAINS RELEGATED TO THE SOUTHWESTERN CONUS. QPF FIELDS
FROM THE SREF- MEAN...NAM AND OPERATIONAL GFS SUGGEST LINGERING
PRECIPITATION WILL BE POSSIBLE OVER OUR SOUTHEASTERN CWA 00Z-06Z
SUNDAY AS A MID LEVEL SHORT WAVE DEPARTS THE AREA. AS A
RESULT...WENT AHEAD AND KEPT 20% POPS GOING ACROSS OUR SOUTHEAST
00Z-06Z SUNDAY. A FEW SMALL-SCALE MID LEVEL PERTURBATIONS COULD
POTENTIALLY PUSH OVER THE CENTRAL PLAINS SUNDAY AND MONDAY.
DESPITE THE POSSIBILITY OF THESE SMALL-SCALE DISTURBANCES...OPTED
TO KEEP THE CWA DRY DURING THIS TIME PERIOD GIVEN THE VERY LOW
PROBABILITY OF PRECIPITATION ACTUALLY BEING REALIZED FROM ANY ONE
OF THESE FEATURES. THE EC...OPERATIONAL GFS AND GEFS-MEAN ALL
ADVERTISE A MORE SIGNIFICANT MID LEVEL SHORT WAVE WILL PUSH
SOUTHEAST ACROSS THE CENTRAL HIGH PLAINS MONDAY NIGHT INTO
TUESDAY. AT THIS TIME IT APPEARS THE BULK OF THE DPVA AND MID
LEVEL THERMAL ADVECTION WILL REMAIN SOUTHWEST OF OUR AREA...BUT
THERE MAY BE JUST ENOUGH OMEGA FOR PRECIPITATION ACROSS OUR
WEST/SOUTHWEST AND AS A RESULT...WENT AHEAD AND KEPT 20%-30% POPS
GOING ACROSS OUR WEST/SOUTHWEST FOR MONDAY NIGHT. SOME OF THIS
OMEGA MAY CREEP A BIT FARTHER EAST INTO OUR AREA DURING THE DAY
TUESDAY SO WENT AHEAD AND SPREAD POPS A BIT FARTHER EAST ACROSS
THE CWA DURING THE DAY TUESDAY AS A RESULT. AN OVERALL LACK IN
KINEMATIC FORCING SHOULD THEN PRESENT DRY CONDITIONS TO OUR AREA
TUESDAY NIGHT THROUGH THURSDAY...WITH GUIDANCE SUGGESTING YET
ANOTHER MID LEVEL SHORT WAVE WILL BRING PRECIPITATION CHANCES TO
MUCH OF THE AREA THURSDAY NIGHT INTO FRIDAY.
VERY LITTLE CHANGE IN THE LOW LEVEL AIRMASS SUGGESTS TEMPERATURES
SUNDAY THROUGH FRIDAY WILL BE FAIRLY SIMILAR...WITH PERHAPS A SLIGHT
WARMING TREND TOWARDS THE END OF THE FORECAST PERIOD. GIVEN
THIS...BELOW-NORMAL TEMPERATURES ARE FORECAST ACROSS THE CWA SUNDAY
WITH HIGHS IN THE UPPER 70S AND LOWS IN THE UPPER 40S TO NEAR 50.
SLIGHTLY WARMER BUT STILL BELOW-NORMAL TEMPERATURES ARE THEN
FORECAST FOR MUCH OF THE CWA MONDAY BEFORE WEAK LOW LEVEL WARM
ADVECTION PROVIDES NEAR TO SLIGHTLY ABOVE-NORMAL TEMPERATURES
TUESDAY ONWARD.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ELKO NV
820 PM PDT SUN AUG 19 2012
.SYNOPSIS...MOISTURE WILL CONTINUE TO PRODUCE A FEW THUNDERSTORMS
MAINLY OVER EASTERN NEVADA THIS EVENING. DRIER AIR ARRIVES IN
NORTHERN NEVADA ON MONDAY...RESTRICTING THUNDERSTORM COVERAGE TO
AREAS SOUTH OF HIGHWAY 50. A SIGNIFICANT ROUND OF THUNDERSTORMS IS
EXPECTED ACROSS EASTERN NEVADA TUESDAY AFTERNOON AND EVENING.
&&
.UPDATE...HAVE ALLOWED THE FLASH FLOOD WATCH TO EXPIRE AS
THUNDERSTORMS HAVE DECREASED OVER THE AREA. STILL MAY SEE LOCAL
HEAVY RAIN SHOWERS THROUGH MIDNIGHT OVER WHITE PINE COUNTY WHERE
THE AIRMASS REMAINS MOIST AND UNSTABLE. AT THE SAME TIME...HAVE
REDUCED POPS WESTERN HALF OF THE CWA WITH A DRIER AIRMASS MOVING
IN.
&&
.PREV DISCUSSION... /ISSUED AT 320 PM /
SHORT TERM...TONIGHT THROUGH TUESDAY. THUNDERSTORMS PRETTY MUCH
FOLLOWING THE EXPECTED SCRIPT THIS AFTERNOON...FAVORING THE
WESTERN AND SOUTHERN ZONES. INSTABILITY IS STRONGEST ACROSS
HUMBOLDT AND WHITE PINE COUNTIES...AND THESE ARE THE AREAS THAT
WILL SEE THE STRONGEST CONVECTION INTO THIS EVENING. EXPECT SHOWER
AND THUNDERSTORMS TO CONTINUE THROUGH THE EARLY EVENING...AS SHOWN
BY 12/18Z NAM AND HRRR SOLUTIONS. WITH PRECIPITABLE WATER NEAR OR
ABOVE 1 INCH...AND K INDEX NEAR 40 WILL MAINTAIN FLASH FLOOD WATCH
FOR CENTRAL NEVADA THROUGH 8 PM. KLRX REFLECTIVITY INDICATES
HEALTHY NE MOVEMENT WITH THE STORMS...BUT WITH SUCH HIGH MOISTURE
CONTENT AND THE POTENTIAL FOR TRAINING ECHOES...WILL LET THE FLASH
FLOOD WATCH CONTINUE. ATMOSPHERE IS PLENTY MOIST...BUT RATHER
LIMITED ON INSTABILITY. REACHING CONVECTIVE TEMPERATURES HAS BEEN
DELAYED SOMEWHAT BY CLOUDS/SHOWERS/MORE STABLE AIR...BUT FEEL
CONVECTION WILL EXPAND INTO THE EVENING. STRONG STORMS AND LOCAL
FLOODING POSSIBLE. EXPECT THUNDERSTORM COVERAGE TO QUICKLY WANE
AFTER SUNSET AS USUAL.
MONDAY...SHORTWAVE RIDGE QUICKLY BUILDS OVER NEVADA...AND MUCH
DRIER AIR INVADES THE NORTHERN ZONES. PW FALLS TO WELL BELOW 0.50
INCH ACROSS ELKO COUNTY. THUNDERSTORM COVERAGE WILL BE RESTRICTED
TO ISOLATED MONDAY...AND CONFINED TO AREAS SOUTH OF U.S. HIGHWAY
50. THE REST OF US MOSTLY SUNNY AND HOT...WITH HIGHS IN THE LOWER
TO MID 90S.
MONDAY NIGHT...MONSOON MOISTURE SURGES QUICKLY NORTHWARD OVERNIGHT
BEHIND DEPARTING RIDGE AXIS...AND AHEAD OF TROUGH APPROACHING FROM
THE WEST. INCREASED CLOUDS AND SHOWER COVERAGE OVERNIGHT...WITH
VERY MILD LOW TEMPERATURES IN THE UPPER 50S AND LOWER 60S TUESDAY
MORNING.
TUESDAY...ACTIVE THUNDERSTORM DAY EXPECTED AHEAD OF APPROACHING
TROUGH...BUT ONLY ACROSS EASTERN NEVADA. MODELS CONTINUE TO
DEPICT AN EXTREMELY TIGHT MOISTURE GRADIENT ACROSS NEVADA...WITH
PW RANGING FROM 1.17 INCH NEAR WENDOVER...DOWN TO LESS THAN 0.25
INCH NEAR WINNEMUCCA. SCATTERED TO NUMEROUS THUNDERSTORMS EXPECTED
TO DEVELOP OVER EASTERN NEVADA /PRIMARILY ELKO AND WHITE PINE
COUNTIES/ TUESDAY AFTERNOON...AHEAD OF A QUASI-DRYLINE THAT WILL
BISECT THE CWA AT PEAK HEATING. CAPE AND BULK SHEAR VALUES WILL
ORGANIZE CONVECTION ACROSS EASTERN NEVADA...AND JET DYNAMICS FROM
APPROACHING TROUGH WILL HELP AS WELL. WITH THE CONSISTENCY IN
MODEL SOLUTIONS...WENT AHEAD AND ADDED WIND/HAIL WORDING TO THE
ZONES FOR EASTERN NEVADA TUESDAY. WESTERN NEVADA BONE DRY IN THE
DRY SLOT...WITH A VERY TIGHT GRADIENT IN THE POP GRIDS. EXPECT
SW TO W WINDS TO INCREASE TO AT LEAST BREEZY LEVELS...AS 700 MB
WINDS INCREASE TO NEAR 20 KTS. BT
LONG TERM...TUESDAY NIGHT THROUGH NEXT SUNDAY. GENERAL AGREEMENT IN
THE MODELS THROUGH THE PERIOD...WITH JUST SOME SUBTLE DIFFS LATE IN
THE WEEK. OVERALL...DRYING AND A LITTLE COOLING...AT LEAST NOT IN
THE UPPER 90S ANY MORE. PERIOD BEGINS WITH THE LEFT OVERS OF THE
SERIOUS TROUGH ON TUESDAY MOVING OUT...AND SOME RESIDUAL CONVECTION
SMACK ALONG THE UTAH LINE TUESDAY NIGHT. BY WEDNESDAY MORNING THE
AIR MASS HAS DRIED OUT. A VERY WEAK QUASI-MONSOONAL PUSH OCCURS
EARLY THURSDAY BUT THE MODELS HAVE IT GETTING ONLY TO SOUTHEAST
WHITE PINE COUNTY. SOME LITTLE INSTABILITY THERE SO KEPT CONVECTION
IN A LIMITED AREA THERE. BY THURSDAY NIGHT THE ATMOSPHERE DRIES OUT
FURTHER AND THERE ARE VERY LOW TO ZERO POPS THE REST OF THE PERIOD.
ANOTHER LITTLE SHORT WAVE WITH ASSOCIATED SURFACE WIND SHIFT LATE
THURSDAY/EARLY FRIDAY WHICH WILL KEEP HIGHS IN THE UPPER 80S OR LOW
90S OVER MOST OF THE AREA. LOWS WILL BE IN THE 40S AND 50S...WITH A
FEW 30S OVER HIGHER TERRAIN...ESPECIALLY IN THE NORTH. BB
AVIATION...CONVECTION WILL BEGIN TO WEAKEN WITH SUNSET OVER THE
GREAT BASIN AND STORMS WILL BECOME ISOLATED AT BEST AFTER 06Z. A FEW
SHOWERS WILL STILL AFFECT CENTRAL AND EASTERN NEVADA THROUGH 12Z.
WILL KEEP VCTS AT KWMC...KTPH...AND KELY...AND VCSH AT KEKO THROUGH
03Z. WILL KEEP VCSH AT KELY THROUGH 06Z. WINDS WILL DROP TO
UPSLOPE/DOWN VALLEY AND LIGHT SPEEDS. BB
FIRE WEATHER...SCATTERED THUNDERSTORMS ACROSS THE FIRE DISTRICT
THROUGH SUNSET THIS EVENING. ELEVATED LAL...BUT MOST STORMS WILL
PRODUCE ENOUGH RAINFALL TO LIMIT NEW LIGHTNING IGNITIONS.
MONDAY...DRIER AIR ACROSS THE NORTHERN FWZ. THUNDERSTORM COVERAGE
WILL BE LIMITED TO ISOLATED...AND CONFINED TO AREAS SOUTH OF U.S.
HIGHWAY 50.
TUESDAY...SCATTERED TO NUMEROUS THUNDERSTORMS EXPECTED ACROSS
EASTERN NEVADA...PRIMARILY FWZ 455...469...470. STRONG STORMS WITH
GUSTY ERRATIC OUTFLOW WINDS ARE POSSIBLE. BT
&&
.LKN WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
87/99/98/98/99
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1033 PM EDT SUN AUG 19 2012
.SYNOPSIS...
A SLOW MOVING FRONT...IN COMBINATION WITH AN UPPER LEVEL
DISTURBANCE...WILL BRING THE CHANCE FOR SHOWERS AND ISOLATED
THUNDERSTORMS TO THE REGION LATER TONIGHT INTO MONDAY EVENING. HIGH
PRESSURE WILL BUILD INTO THE REGION STARTING ON TUESDAY WITH FAIR
WEATHER EXPECTED FOR MID WEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
10 PM UPDATE...
A THIN LINE OF RAIN...WITH SOME THUNDER...HAS DEVELOPED OVER
WESTERN NY AS PREDICTED BY THE HRRR AND LOCAL HIGHER RESOLUTION
MODELS...BUT IT IS NOT AS EXPANSIVE AS THE EARLIER RUNS OF THE
MODELS HAD INDICATED. WITH THAT SAID LIKELY POPS OVER THE NEXT
HOUR OR TWO ACROSS STEUBEN COUNTY NEAR HORNELL AND CHANCE POPS
THROUGH MIDNIGHT OVER THE FINGER LAKES WERE THE MAIN UPDATE TO
MAKE GIVEN WE NOW HAVE ACTION ON THE RADAR. USING THE HRRR AS A
GUIDE...STILL EXPECTING CONVECTION TO PROGRESS EAST AND DISSIPATE
QUICKLY SO BLENDING WITH THE PREVIOUS FORECAST OF SLIGHT CHANCE
POPS OVERNIGHT LOOKS GOOD...ESPECIALLY INTO THE SOUTHERN TIER OF
NY AND NEPA.
7 PM UPDATE...
BASED ON VERY LITTLE RADAR RETURNS AT THE MOMENT...WILL TRIM BACK
POPS THROUGH MIDNIGHT TO SLIGHT CHANCE RANGE. THE HIGHER
RESOLUTION MODELS SUCH AS THE HRRR CONTINUE TO SUGGEST SOME
DEVELOPMENT OF SHOWERS BY 0Z OVER WESTERN NY AND GRADUALLY MOVE
THIS EAST THROUGH 06Z. THE LATEST VIS SATELLITE LOOP DOES SHOW
SOME CLOUDS IN THIS AREA BUT IT SEEMS MOVE LIKELY THAT IF WE SEE
ANYTHING OVERNIGHT...IT WILL BE THANKS TO AN INVERTED TROF OVER
WESTERN PA GRADUALLY MOVING EAST. WITH THAT IN MIND CONTAINED
SLIGHT CHANCE POPS TO EXTEND FROM THE FINGER LAKES (0Z - 4Z) SOUTHEAST
THROUGH THE SOUTHERN TIER OF NY (05Z-10Z) INTO NEPA (06Z-11Z). TO
BLEND BETTER WITH TOMORROW`S FORECAST I SHOW A LULL EARLY IN THE
DAY WITH A TRANSITION TO INCREASING POPS...AS THIS STILL APPEARS
LIKELY WITH THE COMBINATION OF DIURNAL HEATING AND A FRONT MOVING
INTO THE AREA. WITH A GENERAL INCREASE IN MID LEVEL CLOUDS
TONIGHT...WIDESPREAD VALLEY FOG IS NOT EXPECTED. THE PREVIOUS AFD IS
BELOW...
SFC ANYLS SHOWS A CDFNT ACRS LOWER ONTARIO INTO CNTRL MI WITH
AN INVERTED TROF DVLPNG OVER ERN OH/WRN PA. AT UPR LVLS...THE DEEP
TROF OVER THE ERN U.S. WILL GRADUALLY LIFT NEWD/PULL OUT...WITH
MDLS SUGGESTING THE CDFNT/INVERTED TROF WILL EVENTUALLY MERGE AND
WORK EWD ACRS THE BGM FCST AREA ON MON...AS LOW PRES TRACKS NEWD
OFF THE MID ATLC CST. THE MAIN TROF AXIS WON`T PASS THE FCST AREA
TIL WED....WITH UPR FLOW BCMG GNRLY ZONAL BY WED EVNG.
GRADUAL MOISTENING WILL OCCUR OVRNGT AS SRLY FOW DVLPS AHEAD OF THE
SFC TROF/FNT. SHORT RNG MESO MDLS INCLUDING THE RUC AND LCL WRF SUGGEST
THAT ACTIVITY ACRS CNTRL PA COULD TRACK NWD INTO THE CNTRL SRN
TIER THIS EVNG ALONG AND EAST OF THE SFC TROF...AND HINTS THAT
ADDNL ISOLD/WDLY SCT DVLPMNT IS PSBL...SO WE INDICATE LOW CHC POPS
SPREADING N AND NE ACRS THE FCST AREA OVRNGT.
ANOTHER S/WV IS FCST TO APRCH THE RGN TMRW AFTN...AND THIS IN
COMBINATION WITH THE SFC BNDRY SHUD HELP TO FOCUS ACTIVITY ACRS
CNTRL/ERN ZONES ON MON AFTN. CHCS FOR TSRA WILL BE ON THE LOW SIDE
GIVEN LIMITED INSTABILTY. TEMPS COULD BE TRICKY ON MON...FOR NOW
INDICATED COOLEST MAXES ACRS SE ZONES (A70 OR L70S).
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
SHRA ARE XPCTD TO DIMINISH/MOV OUT ON MON EVNG. MDLS SUGGEST
POTNL FOR ISOLD ACTIVITY FAR SRN TIER AND NE PA ON TUE AND PSBLY WED.
OVERALL THE PTRN DOES NOT LOOK AS FVRBL FOR DIURNAL CONVECTIVE
DVLPMNT AS SFC HI PRES WILL BE BUILDING INTO THE RGN...AND
INSPECTION OF 12Z NAM/GFS PROFILES SHOWS VERY LIMITED CAPE SO
WILL LOWER POPS TO SLGT CHC THESE AREAS FOR TUE/WED AFTN. OTRW...NICE
WX WITH SEASONABLE TEMPS AND PS DAYS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
SUBTLE FEATURES WILL INFLENCE THE WX IN THE LONG TERM AS THE SFC
RDGG BRKS DOWN EARLY IN THE PD. OPERATIONAL MODELS SHOW A WEAK FNTL
BNDRY TRYING TO DROP SOUTH FROM CANADA FRI INTO SAT BEFORE
EVENTUALLY WASHING OUT OVER THE AREA. WITH HTG...THIS MAY BE ENUF
LL CONV TO DVLP ISLTD AFTN CONV FRI AND SAT.
TEMPS WILL SHOW A GRADUAL RECOVERY THRU THE PD...RCHG ABV NRML BY
FRI AND SAT. STILL DFRNCS BETWEEN HPC GUID AND GFS GENERATED
MEX...SO BLENDED GUID WITH PRVS FCST TO CONT A SLOW UPWARD TREND.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
AREA WILL REMAIN BETWEEN A WEAK COLD FRONT MOVING THROUGH NEARBY
SOUTHERN ONTARIO AND SFC LOW PRES MOVING NORTHEAST ALONG THE MID
ATLANTIC COAST. THESE FEATURES WILL BRING INCREASING MID LEVEL
CLOUDS THROUGH 06Z FOLLOWED BY CIGS LOWERING TO 4-5K FT BETWEEN
06Z-12Z. DAYTIME HEATING AND PASSAGE OF WEAK BOUNDARY WILL LEAD TO
MVFR RAIN SHOWERS ON MONDAY. ACTIVITY WILL BE MOST WIDESPREAD FROM
MID MORNING THROUGH MID AFTERNOON. AT KAVP, MVFR RAIN SHOWER RESTRICTIONS
MAY ALSO OCCUR EARLIER 08Z-12Z DUE TO WAVE MOVING UP THE COAST.
WINDS WILL BE LIGHT AND VARIABLE THROUGH MONDAY AFTERNOON THEN
BECOMING W/NW AROUND 5 KNOTS.
OUTLOOK...
TUE...SCT MVFR PSBL IN AFTN SHRA/TSRA.
WED/THU/FRI...MAINLY VFR. MRNG VLY FOG PSBL WITH IFR AT ELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...HEDEN
SHORT TERM...
LONG TERM...DGM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
751 PM EDT SUN AUG 19 2012
.SYNOPSIS...
A SLOW MOVING FRONT...IN COMBINATION WITH AN UPPER LEVEL
DISTURBANCE...WILL BRING THE CHANCE FOR SHOWERS AND ISOLATED
THUNDERSTORMS TO THE REGION LATER TONIGHT INTO MONDAY EVENING. HIGH
PRESSURE WILL BUILD INTO THE REGION STARTING ON TUESDAY WITH FAIR
WEATHER EXPECTED FOR MID WEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
7 PM UPDATE...
BASED ON VERY LITTLE RADAR RETURNS AT THE MOMENT...WILL TRIM BACK
POPS THROUGH MIDNIGHT TO SLIGHT CHANCE RANGE. THE HIGHER
RESOLUTION MODELS SUCH AS THE HRRR CONTINUE TO SUGGEST SOME
DEVELOPMENT OF SHOWERS BY 0Z OVER WESTERN NY AND GRADUALLY MOVE
THIS EAST THROUGH 06Z. THE LATEST VIS SATELLITE LOOP DOES SHOW
SOME CLOUDS IN THIS AREA BUT IT SEEMS MOVE LIKELY THAT IF WE SEE
ANYTHING OVERNIGHT...IT WILL BE THANKS TO AN INVERTED TROF OVER
WESTERN PA GRADUALLY MOVING EAST. WITH THAT IN MIND CONTAINED
SLIGHT CHANCE POPS TO EXTEND FROM THE FINGER LAKES (0Z - 4Z) SOUTHEAST
THROUGH THE SOUTHERN TIER OF NY (05Z-10Z) INTO NEPA (06Z-11Z). TO
BLEND BETTER WITH TOMORROW`S FORECAST I SHOW A LULL EARLY IN THE
DAY WITH A TRANSITION TO INCREASING POPS...AS THIS STILL APPEARS
LIKELY WITH THE COMBINATION OF DIURNAL HEATING AND A FRONT MOVING
INTO THE AREA. WITH A GENERAL INCREASE IN MID LEVEL CLOUDS
TONIGHT...WIDESPREAD VALLEY FOG IS NOT EXPECTED. THE PREVIOUS AFD IS
BELOW...
SFC ANYLS SHOWS A CDFNT ACRS LOWER ONTARIO INTO CNTRL MI WITH
AN INVERTED TROF DVLPNG OVER ERN OH/WRN PA. AT UPR LVLS...THE DEEP
TROF OVER THE ERN U.S. WILL GRADUALLY LIFT NEWD/PULL OUT...WITH
MDLS SUGGESTING THE CDFNT/INVERTED TROF WILL EVENTUALLY MERGE AND
WORK EWD ACRS THE BGM FCST AREA ON MON...AS LOW PRES TRACKS NEWD
OFF THE MID ATLC CST. THE MAIN TROF AXIS WON`T PASS THE FCST AREA
TIL WED....WITH UPR FLOW BCMG GNRLY ZONAL BY WED EVNG.
GRADUAL MOISTENING WILL OCCUR OVRNGT AS SRLY FOW DVLPS AHEAD OF THE
SFC TROF/FNT. SHORT RNG MESO MDLS INCLUDING THE RUC AND LCL WRF SUGGEST
THAT ACTIVITY ACRS CNTRL PA COULD TRACK NWD INTO THE CNTRL SRN
TIER THIS EVNG ALONG AND EAST OF THE SFC TROF...AND HINTS THAT
ADDNL ISOLD/WDLY SCT DVLPMNT IS PSBL...SO WE INDICATE LOW CHC POPS
SPREADING N AND NE ACRS THE FCST AREA OVRNGT.
ANOTHER S/WV IS FCST TO APRCH THE RGN TMRW AFTN...AND THIS IN
COMBINATION WITH THE SFC BNDRY SHUD HELP TO FOCUS ACTIVITY ACRS
CNTRL/ERN ZONES ON MON AFTN. CHCS FOR TSRA WILL BE ON THE LOW SIDE
GIVEN LIMITED INSTABILTY. TEMPS COULD BE TRICKY ON MON...FOR NOW
INDICATED COOLEST MAXES ACRS SE ZONES (A70 OR L70S).
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
SHRA ARE XPCTD TO DIMINISH/MOV OUT ON MON EVNG. MDLS SUGGEST
POTNL FOR ISOLD ACTIVITY FAR SRN TIER AND NE PA ON TUE AND PSBLY WED.
OVERALL THE PTRN DOES NOT LOOK AS FVRBL FOR DIURNAL CONVECTIVE
DVLPMNT AS SFC HI PRES WILL BE BUILDING INTO THE RGN...AND
INSPECTION OF 12Z NAM/GFS PROFILES SHOWS VERY LIMITED CAPE SO
WILL LOWER POPS TO SLGT CHC THESE AREAS FOR TUE/WED AFTN. OTRW...NICE
WX WITH SEASONABLE TEMPS AND PS DAYS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
SUBTLE FEATURES WILL INFLENCE THE WX IN THE LONG TERM AS THE SFC
RDGG BRKS DOWN EARLY IN THE PD. OPERATIONAL MODELS SHOW A WEAK FNTL
BNDRY TRYING TO DROP SOUTH FROM CANADA FRI INTO SAT BEFORE
EVENTUALLY WASHING OUT OVER THE AREA. WITH HTG...THIS MAY BE ENUF
LL CONV TO DVLP ISLTD AFTN CONV FRI AND SAT.
TEMPS WILL SHOW A GRADUAL RECOVERY THRU THE PD...RCHG ABV NRML BY
FRI AND SAT. STILL DFRNCS BETWEEN HPC GUID AND GFS GENERATED
MEX...SO BLENDED GUID WITH PRVS FCST TO CONT A SLOW UPWARD TREND.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AREA WILL REMAIN BETWEEN A WEAK COLD FRONT MOVING THROUGH NEARBY
SOUTHERN ONTARIO AND SFC LOW PRES MOVING NORTHEAST ALONG THE MID
ATLANTIC COAST. THESE FEATURES WILL BRING INCREASING MID LEVEL
CLOUDS THROUGH 06Z FOLLOWED BY CIGS LOWERING TO 4-5K FT BETWEEN
06Z-12Z. DAYTIME HEATING AND PASSAGE OF WEAK BOUNDARY WILL LEAD TO
MVFR RAIN SHOWERS ON MONDAY. ACTIVITY WILL BE MOST WIDESPREAD FROM
MID MORNING THROUGH MID AFTERNOON. AT KAVP, MVFR RAIN SHOWER RESTRICTIONS
MAY ALSO OCCUR EARLIER 08Z-12Z DUE TO WAVE MOVING UP THE COAST.
WINDS WILL BE LIGHT AND VARIABLE THROUGH MONDAY AFTERNOON THEN
BECOMING W/NW AROUND 5 KNOTS.
OUTLOOK...
TUE...SCT MVFR PSBL IN AFTN SHRA/TSRA.
WED/THU/FRI...MAINLY VFR. MRNG VLY FOG PSBL WITH IFR AT ELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...HEDEN
SHORT TERM...
LONG TERM...DGM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
842 PM EDT SUN AUG 19 2012
.SYNOPSIS...
RAIN SHOWERS AND ISOLATED THUNDERSTORMS WILL PREVAIL TODAY AS A
DISTURBANCE OVER THE GULF STATES TRACKS TO THE NORTHEAST ALONG A
STATIONARY FRONTAL BOUNDARY ACROSS THE REGION. AN UNSETTLED WEATHER
PATTERN WILL PERSIST THROUGH MID WEEK...AS THE FRONT REMAINS STALLED
OVER THE CAROLINAS. A DRYING TREND IS EXPECTED LATE IN THE WEEK AS
HIGH PRESSURE BUILDS FROM THE WEST AND PUSHES THE FRONT OUT TO SEA.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 830 PM SUNDAY...ONLY ISOLATED CONVECTION CONTINUES MAINLY
SOUTHWEST OF THE COUNTY WARNING AREA. THE LATEST HRRR INDICATES
THAT CONVECTION MAY DEVELOP OVERNIGHT TO THE SOUTHWEST AND SPREADING
NORTHWEST INTO OUR AREA LATER THIS EVENING. AT THIS TIME WILL CONTINUE
WITH THE SCATTERED TO ISOLATED CONVECTION OVERNIGHT.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
AS OF 3 PM SUNDAY...THE AXIS OF THE UPPER LEVEL TROUGH WILL
REMAIN TO THE WEST AND WEAK IMPULSES WILL ROTATE AROUND THIS
FEATURE. THE PRECIPTABLE WATER WILL REMAIN AT OR ABOVE 2 INCHES
THROUGH TUESDAY MORNING WITH A SLOW DRYING TREND TOWARDS THE END.
SPC DOES MENTION MARGINAL DAMAGING WIND POTENTIAL ON TUESDAY.
WITH THE INSTABILITY AND MOISTURE WILL INCLUDE A HIGH CHANCE OF
CONVECTION EACH DAY.
MAXIMUM TEMPERATURES ARE EXPECTED TO REACH THE MID 80S EACH DAY
AND MINIMUM TEMPERATURES AROUND 70S MONDAY AND UPPER 60S TUESDAY
NIGHT AS COOLER HIGH PRESSURE PUSHES THE WARMER AND MOIST AIR TO
THE SOUTH AND EAST.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 3 PM SUNDAY...HIGH PRESSURE WILL BUILD INTO THE REGION AND
PUSH THE STATIONARY FRONT ALONG THE COAST OUT TO SEA. THIS WILL
ALLOW FOR DRIER AND COOLER AIR. THE WILL BE A CHANCE OF CONVECTION
EARLY WEDNESDAY AND AS WE PROGRESS INTO THE WEEKEND ONLY AN
ISOLATED THUNDERSTORM IS EXPECTED. MAXIMUM TEMPERATURE ARE
EXPECTED TO BE IN THE MID 80S DURING THE DAY AND MINIMUM
TEMPERATURES WILL BE DROP FROM THE UPPER 60S ON WEDNESDAY TO THE
MID 60S BY THE WEEKEND.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
AS OF 12Z...ISOLATED AREAS OF BRIEF MVFR THROUGH THE EARLY
OVERNIGHT HOURS...WITH MVFR/IFR DUE TO FOG AND STRATUS LATE
OVERNIGHT INTO THE LATE MORNING HOURS. CONDITIONS MAY IMPROVE TO
VFR MONDAY AFTERNOON...THOUGH VCSH AND VCTS ARE EXPECTED
THROUGHOUT THE DAY.
ISOLATED SHRA OUTSIDE OF OUR AREA MAY LINGER IN WITHIN THE NEXT FEW
HOURS...BUT OVERALL ANTICIPATE VFR WITH LIGHT AND VARIABLE WINDS
THROUGH THE OVERNIGHT HOURS. MODELS CONTINUE TO PROJECT MVFR/IFR
DUE TO LOW CIGS AND POSSIBLE FOG LATE OVERNIGHT INTO THE MORNING
HOURS...THUS HAVE KEPT TREND IN CURRENT FCST. INTO THE MORNING
HOURS...WINDS WILL REMAIN LIGHT WITH ISOLATED TO SCATTERED LIGHT
RAIN SHOWERS. INTO THE AFTERNOON HOURS...CANNOT RULE OUT ISOLATED
TO SCATTERED TSRA...THUS HAVE INTRODUCED VCTS INTO CURRENT FCST.
WEST-SOUTHWEST WINDS WILL CONTINUE THROUGH THE DAY WITH SUSTAINED
SPEEDS AOB 10 KTS.
EXTENDED OUTLOOK...SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITH
TEMPO MVFR/IFR THROUGH TUESDAY. ISOLATED SHOWERS AND THUNDERSTORMS
WEDNESDAY THROUGH FRIDAY.
&&
.MARINE...
NEAR TERM /THROUGH 6 AM MONDAY/...
AS OF 830 PM SUNDAY...SOUTHWEST WINDS OF 10 KNOTS ARE CONTINUING
OVER THE WATERS AS A WEAK FRONTAL BOUNDARY WAVERS BACK AND FORTH
INLAND OVERNIGHT. SEAS WILL RANGE FROM 2 TO 4 FEET. HRRR MODEL IS HINTING
OF CONVECTION DEVELOPING TO THE SOUTHWEST OF THE COASTAL WATERS
AND MOVING ACROSS OVERNIGHT. CONFIDENCE IS LOW SO WILL LEAVE CHANCE
OF THUNDERSTORMS IN FOR OVERNIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...WITH FRONTAL BOUNDARY SLOWLY MOVING TO THE WATERS
BY THE END OF THE PERIOD...WIND SPEEDS ARE EXPECTED TO BE AROUND
10 TO 15 KNOTS AND SEAS RANGING BETWEEN 2 TO 4 FEET. AS
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 PM SUNDAY...AS THE FRONTAL BOUNDARY LINGERS AT THE COAST
THE COASTAL WATER WINDS WILL BE AROUND 10 T0 15 KNOTS AND AS HIGH
PRESSURE BUILDS OVER THE WATERS BY THURSDAY WINDS WILL BE LIGHT
FROM THE NORTH TO NORTHWEST. SEAS OF 3 FT OR LESS ARE EXPECTED
THROUGH THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HAWKINS
SHORT TERM...HAWKINS
LONG TERM...HAWKINS
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1140 AM EDT SAT AUG 18 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL APPROACH THE AREA TODAY...THEN STALL OVER
EASTERN NORTH CAROLINA TONIGHT INTO MONDAY BEFORE MOVING
OFF THE COAST TUESDAY. HIGH PRESSURE WILL BUILD INTO THE AREA
TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1100 AM SATURDAY...UPDATED TO DELAY LIKELY POPS FOR
SHOWERS/TSTMS UNTIL PRIME CONVECTIVE TIME OF 2 PM TO 6 PM. MOST
MODELS WERE OVERDONE WITH PCPN FCST DURING MORNING HOURS WITH ONLY
SCT ACTIVITY ACCOMPANYING THICKER CLOUD LAYER WITH SHRT WV. SKIES
HAVE CLEARED BEHIND THIS FEATURE AND SFC OBS INDICATE WIND SHIFT
WITH FRONTAL BNDRY HAS PUSHED INTO NRN OBX AND COASTAL PLAINS. THIS
WILL ALLOW GOOD HEATING OVER INLAND SECTIONS THROUGH EARLY AFTN AND
CONVERGENCE ALONG BNDRY AND SEA BREEZE MOVING INLAND EXPECTED TO
PRODUCE GOOD COVERAGE OF SHOWERS/TSTMS...THUS CONTINUED LIKELY POPS
ALL BUT CENTRAL AND SRN OBX. SLGT RISK OF SVR FOR AREA MAY BE
SLIGHTLY OVERDONE WITH GENERALLY WEAK WIND FIELDS SUPPORTING ONLY
ISOLATED SVR. NO CHANGES TO TEMPS.
/PREVIOUS DISCUSSION/
AS OF 635 AM SATURDAY...NO CHANGES TO PREVIOUS THINKING. A BROAD
UPPER TROUGH WITH SEVERAL EMBEDDED SHORTWAVES CONTINUES OVER THE
CENTRAL AND EASTERN US. ISOLATED SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED EARLY THIS MORNING BUT MOST OF EASTERN NC IS DRY. A
WEAK COLD FRONT WILL BE MOVING INTO THE AREA AND IS EXPECTED TO
ENHANCE THE SHOWER AND THUNDERSTORM THREAT TODAY. ALL OF THE
GUIDANCE IS INDICATING THAT THE PRECIPITATION WILL DEVELOP RAPIDLY
THIS MORNING AND HAVE INCREASED EARLY POPS TO LIKELY ALL BUT THE
FAR EAST ZONES BUT HAVE DELAYED ONSET OF WIDESPREAD PRECIPITATION
FROM 11Z TO 14Z. SPC CONTINUES TO HAVE EASTERN NC IN A "SLIGHT
RISK FOR SEVERE" TODAY DUE TO MODERATE INSTABILITY AND UPPER LEVEL
SHEAR WHICH WOULD SUPPORT MULTI-CELL CLUSTERS CAPABLE OF PRODUCING
DAMAGING WIND GUSTS AND LARGE HAIL. LIMITING FACTOR WILL BE CLOUD
DECK MOVING INTO EASTERN NC EARLY THIS MORNING (ALTHOUGH LOOKS
LIKE THESE CLOUDS ARE BEGINNING TO ERODE)...AND EXPECTED EARLY
START TO THE PRECIPITATION. TREND OF MID CLOUD DECK ACROSS EASTERN
NC THIS MORNING IS FOR CLOUDS TO DISSIPATE SO WE WILL HAVE AT
LEAST POCKETS OF SUBSTANTIAL HEATING. WITH PW VALUES AROUND 2"
LOCALLY HEAVY RAINS WILL OCCUR WITH URBAN AND POOR DRAINAGE
FLOODING POSSIBLE IF TRAINING OF CELLS OCCURS.
HIGH TEMPERATURES TODAY WILL HIGHLY DEPENDENT ON THE AMOUNT OF
INSOLATION THAT OCCURS. I WENT WITH A BLEND OF THE COOL MET (LOWER
80S) AND WARMER MAV (UPPER 80S) TO YIELD HIGHS IN THE MIDDLE 80S
AREA WIDE. SOUTHERLY WINDS EARLY WILL GRADUALLY SHIFT TO THE LIGHT
NORTHWEST AND NORTH THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
AS OF 340 AM SATURDAY...THERE IS STRONG AGREEMENT IN THE GUIDANCE
SUGGESTING A DRYING TREND LATE THIS EVENING AND OVERNIGHT AS THE
FRONT OR WIND SHIFT BRIEFLY MOVES JUST OFF OF THE COAST SO WILL
INDICATE A DRY PERIOD AFTER 06Z WITH SCATTERED SHOWERS AND
THUNDERSTORMS ENDING IN THE EVENING. OVERNIGHT LOWS WILL RANGE
FROM THE MIDDLE TO UPPER 60S INLAND TO TO THE LOWER TO MIDDLE 70S
ALONG THE COAST.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 340 AM SAT...AN UNSETTLED PATTERN WILL BE THE RULE THROUGH
EARLY NEXT WEEK. SLOW-MOVING COLD FRONT IN THE WESTERN PART OF THE
STATE WILL SLOWLY APPROACH THIS WEEKEND...EVENTUALLY DRIFTING OFF
THE COAST EARLY NEXT WEEK. HAVE KEPT POPS IN THE CHANCE CATEGORY
FOR SUNDAY BUT BUMPED UP POPS TO 50 PERCENT SUNDAY NIGHT AND 60
PERCENT MONDAY AS BETTER VORT ENERGY IN THE LOWER AND MID LEVELS
PASSES THROUGH.
ATMS SHOULD DRY OUT SLOWLY TUE AS FRONT MOVES OFFSHORE. UPPER
TROUGH WILL MOVE INTO THE EASTERN US EARLY NEXT WEEK THROUGH MID
WEEK RESULTING IN LOW LEVEL N/NE FLOW...CLOUDY CONDITIONS AND
TEMPS SLIGHTLY BELOW NORMAL...HIGHS GENERALLY LOW TO MID 80S AND
OVERNIGHT LOWS IN THE MID 60S TO MID 70S. UPPER FLOW BEGINS TO
BECOME MORE ZONAL LATE WEEK WITH TEMPS LIKELY WARMING A FEW
DEGREES.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /THROUGH SATURDAY NIGHT/...
AS OF 1240 AM SATURDAY...WIDESPREAD MID AND OPAQUE HIGH CLOUDS
WILL CONTINUE TO SPREAD EAST OVER EASTERN NC OVERNIGHT AND HELP TO
SUPPRESS RADIATIONAL COOLING AND THUS DENSE FOG POTENTIAL OVERNIGHT
WITH ONLY A BRIEF PERIOD OF MVFR FOG POSSIBLE AT THE TAF SITES.
SCATTERED SHOWERS AND STORMS ARE EXPECTED TO REDEVELOP LATE
TONIGHT AS THE SHORTWAVE MOVES INTO THE AREA AND WILL CONTINUE
THROUGH MUCH OF SATURDAY AS A WEAK COLD FRONT AND DEEPER MOISTURE
MOVES INTO THE AREA. SOMEWHAT DRIER AIR IS FORECAST TO SPREAD INTO
EASTERN NC SATURDAY NIGHT WHICH WILL LEAD TO A DECREASE IN IN
SHOWER THUNDERSTORM ACTIVITY AFTER 00Z.
LONG TERM /SUNDAY THROUGH WEDNESDAY/...
S OF 340 AM SAT...LOCALLY LOWER VSBYS/CIGS THIS WEEKEND THROUGH
EARLY NEXT WEEK IN SCATTERED SHOWERS AND THUNDERSTORMS. ACTIVITY
WILL BECOME ISOLATED BY MIDWEEK. SOUTHWEST SURFACE FLOW CONTINUES
THROUGH TUESDAY MORNING THEN BECOMES LIGHT AND VARIABLE. WINDS
WILL THEN BECOME LIGHT EAST TO NORTHEAST FOR WEDNESDAY.
LOW LEVEL N/NE FLOW WILL LIKELY RETURN TUE/WED AS HIGH PRESSURE
BUILDS BEHIND THE FRONTAL BOUNDARY...LOWERED CIGS WILL BE
POSSIBLE.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 1100 AM SATURDAY...UPDATED FOR WINDS SHIFTING OVER NRN WATERS
THIS AFTN WITH FRONTAL PROTRUSION. RUC13 APPEARS TO HAVE BEST HANDLE
ON CURRENT WINDS WITH FRONT MOVING INTO NRN WATERS WITH NRLY WINDS
OBSERVED JUST N OF VA BORDER. WIND SHIFT WITH THIS FEATURE EXPECTED
TO PUSH INTO NRN PAMLICO SOUND AND BETWEEN HAT AND ORE INLET EARLY
AFTN. SW WINDS 15 KT OR LESS WILL PREVAIL OVER SRN HALF OF WATERS.
/PREVIOUS DISCUSSION/
AS OF 635 AM SATURDAY...NO CHANGES TO PREVIOUS THINKING. SOUTHERLY
FLOW TO 15 KT CONTINUES AHEAD OF APPROACHING WEAK COLD FRONT. THIS
FLOW IS FORECAST TO CONTINUE THROUGH THIS MORNING THEN RELAX THIS
AFTERNOON AND TONIGHT AS A WEAK COLD FRONT BECOMES MORE DIFFUSE
AND SETTLES OVER THE NORTHERN AND CENTRAL NC WATERS DECREASING THE
PRESSURE GRADIENT. WINDS WILL BRIEFLY SHIFT TO THE NORTHWEST AND
NORTH AS THE FRONT IS FORECAST TO STALL JUST OFF OF THE NORTHERN
AND CENTRAL WATERS. 2-3 FT SEAS ARE EXPECTED THROUGH TONIGHT WITH
SOME 4 FT SETS ACROSS THE OUTER WATERS POSSIBLE THIS MORNING. THE
SEAS WILL BE A COMBINATION OF A ESE SWELL AT 9 SECONDS AND A S TO
SW WIND WAVE WITH A PERIOD AROUND 5 SECONDS.
LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 340 AM SAT...MODELS IN GOOD AGREEMENT SUNDAY...BUT BY EARLY
NEXT WEEK THE 00Z GFS HAS A MORE AMPLIFIED SOLUTION AS COMPARED TO
THE 17/12Z ECMWF AND THE SREF. SO FOR THIS PACKAGE I HAVE USED A
BLEND OF THESE TWO MODELS. THE SLOW-MOVING COLD FRONT WILL DRIFT
OFF THE COAST EARLY NEXT WEEK. BY WEDNESDAY THE SURFACE HIGH WILL
MOVE OVER THE REGION. THE SOUTHWEST FLOW WILL CONTINUE FROM SUNDAY
THROUGH TUESDAY MORNING AND THEN BECOME LIGHT AND VARIABLE. WINDS
WILL THEN BECOME LIGHT EAST TO NORTHEAST FOR WEDNESDAY. NO
HEADLINES EXPECTED AS WINDS AND SEAS WILL REMAIN BELOW SMALL
CRAFT LEVELS.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JME
NEAR TERM...JME/JBM
SHORT TERM...JME
LONG TERM...HSA
AVIATION...JME/HSA
MARINE...JME/HSA/JBM
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
753 PM EDT SUN AUG 19 2012
.SYNOPSIS...
A SERIES OF DISTURBANCES ALOFT PASSING INTO TUESDAY. WEAK HIGH
PRESSURE FOR WEDNESDAY THROUGH THE END OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
UPDATE...
ELEVATED ISOLATED TO SCATTERED CONVECTION CONTINUING WITH THE AID
OF A VORTICITY MAX ALOFT OVER SOUTHERN OHIO AND ANOTHER OVER THE
TENNESSEE MOUNTAINS. RUC TAKES THIS THROUGH 04-06Z. EARLIER
CONVECTION HAS COOLED THE NORTHEAST ZONES CONSIDERABLY...BUT
ACTUALLY TWEAKED THE OVERNIGHT LOWS UPWARDS A COUPLE NOTCHES.
DESPITE LINGERING CLOUDS...COULD SEE MIST/FOG DEVELOPMENT IN THE
VALLEYS HERE TONIGHT.
PREVIOUS DISCUSSION...
UPR DISTURBANCE HAS PUSHED OUT OF THE CWA AS OF 18Z...WITH AN
ABUNDANCE OF LLVL MOISTURE LEFT IN ITS WAKE ACROSS THE MTNS. DRIER
AIR THOUGH HAS FILTERED INTO SE OH WITH DWPTS RUNNING IN THE UPR
40S TO LWR 50S. SCT TO BKN MAINLY HIGH BASED CU FIELD W OF THE
MTNS WITH A FEW SHRA POPPING UP. WILL MAINTAIN CHC POPS ACROSS
CENTRAL AND EASTERN ZONES THIS AFTN WITH NEAR TERM MDLS CONT TO
SHOW MAINLY SCT SHRA DEVELOPMENT AND PERHAPS A RUMBLE OF THUNDER
OR TWO. ELECTED TO BRING IN CHC POPS ACROSS SE OH AS WELL THIS
AFTN...WITH SCT SHRA BACK CLOSER TO UPR TROF WITH MDLS SHOWING
THIS TRANSITIONING INTO CENTRAL PARTS OF CWA THIS EVENING
WARRANTING HOLDING ON TO SCHC POPS THIS EVENING.
CLOUD/FG FCST TRICKY AGAIN TONIGHT. MDLS HOLD ON TO LLVL MOISTURE
MAINLY ACROSS THE MTNS WHERE A COMBO FG/LOW STRATUS SITUATION
LOOKS TO MATERIALIZE TONIGHT...ESPECIALLY GIVEN RAINS ACROSS
EASTERN SLOPES UP INTO POCAHONTAS AND EASTERN RANDOLPH THIS
MORNING. THINK DRIER AIR FURTHER W WILL PREVENT MUCH IN WAY OF
DENSE FG IN RVR VALLEYS BUT THIS WILL NEED TO BE MONITORED THIS
EVENING.
UPR TROF AXIS STAYS W OF AREA TOMORROW BUT WITH SUBTLE RIPPLES IN
THE FLOW...HAD TO KEEP LOW DIURNAL POPS IN FCST...GREATEST OVER SE
OH AND IN THE MTNS.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
MODELS SHOWING SOME WEAK DISTURBANCES MONDAY NIGHT AND TUESDAY...BUT
TIMING AND PLACEMENT OF DISTURBANCES VARY BASED ON THE MODEL. WITH
SOME MOISTURE OVER THE AREA...WILL KEEP SOME SMALL POPS EVEN DURING
THE NIGHT AND MORNING HOURS. DRIER AIR ALOFT SLIDES IN ON
WEDNESDAY...BUT MAY BE JUST ENOUGH MOISTURE IN THE EASTERN MOUNTAINS
FOR A FEW AFTERNOON SHOWERS/THUNDERSTORMS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
USED A BLEND OF THE GEFS MEAN...ECMWF AND ECMWF MEAN. THIS LEAVES A
WEAK HIGH PRESSURE SYSTEM OVER THE REGION FOR THURSDAY AND FRIDAY...
BUT POSSIBLY ENOUGH MOISTURE TO FIRE SOME AFTERNOON
SHOWERS/THUNDERSTORMS IN THE MOUNTAINS. BY THE WEEKEND...A SOUTHERLY
FLOW IN ADVANCE OF AN APPROACHING SYSTEM MAY PROVIDE ENOUGH
MOISTURE FOR SHOWERS OR THUNDERSTORMS THROUGHOUT THE REGION.
&&
.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
MODELS INSISTENT ON MID LEVEL MOISTURE PERSISTING TONIGHT...WHICH
MEANS A SCATTERED TO BROKEN CLOUD DECK WILL BE PERSISTENT THROUGH
THE NIGHT. THIS SHOULD TEMPER THE POTENTIAL FOR FOG OVER THE
WESTERN ZONES...BUT OVER THE EASTERN ZONES WHERE RAIN WAS
RECEIVED...VALLEY MIST/FOG IS POSSIBLE. SOME IFR...WITH BRIEF LIFR
NOT OUT OF THE QUESTION AT EKN...DESPITE THE SCT-BKN VFR DECK. IN
THE EASTERN SLOPES...SATURATED SOUTHEAST FLOW WILL BRING A LOW
STRATUS DECK TONIGHT...WHICH SHOULD AFFECT BKW...BUT NOT EKN.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: FOG MAY BE MORE WIDESPREAD 06Z TO 12Z SHOULD
LESS STRATUS FORMS OVER THE MTNS. IN ADDITION RVR VALLEY FG MAY BE
MORE PREVALENT ELSEWHERE SHOULD LOW LEVEL DRY AIR NOT HOLD.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE MON 08/20/12
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
CRW CONSISTENCY M M M H H H H M M M M M
HTS CONSISTENCY H H H H H H H H H M M M
BKW CONSISTENCY M M M M H H H H L L L L
EKN CONSISTENCY H H H H H H M M L L L L
PKB CONSISTENCY H H H H H H H H M M M M
CKB CONSISTENCY M M M M M H H H M M M M
AFTER 00Z TUESDAY...
BRIEF IFR CONDITIONS POSSIBLE IN THUNDERSTORMS TUESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...30/26
SHORT TERM...RPY
LONG TERM...RPY
AVIATION...26
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1050 PM EDT SUN AUG 19 2012
.SYNOPSIS...
A COLD FRONT WILL REMAIN STALLED OVER THE WESTERN CAROLINAS THROUGH
TUESDAY. A SERIES OF WEAK LOWS WILL MOVE UP THE FRONTAL BOUNDARY
THROUGH TUESDAY. BY MID WEEK THE FRONT WILL GRADUALLY MOVE TO THE
COAST ALLOWING WEAK HIGH PRESSURE TO BUILD INTO THE REGION FROM THE
WEST.
&&
.NEAR TERM /THROUGH MONDAY/...
AT OF 1045 PM...PER AN INTERMEDIATE UPDATE WE SLOWED THE ADVANCE
EAST OF THE PRECIPITATION OUT OF OUR FORECAST AREAA (FA) OVERNIGHT
AS NEXT WAVE SURGES NEWD IN PSEUDO TROPICAL PLUME OF MOISTURE.
RAINFALL CONTINUES TORRENTIAL IN SOME SPOTS...BUT IT IS LOCALIZED
AND DOES NOT REQUIRE AN AREAL WATCH. EVENTUALLY HEAVY SHOWERS WILL
BECOME FOCUSED IN OUR FAR SOUTH AND EAST FORECAST AREA AFTER
MIDNIGHT. ON OUR WESTERN FLANK...MIXED SIGNALS ABOUT HOW MUCH
CLEARING WILL TAKE PLACE. IT MAY VERY WELL WORK OUT THAT JUST ENOUGH
CLOUDS HOLD TO KEEP WIDESPREAD VISIBILITIES FROM GETTING OUT OF
HAND. HOWEVER CONFIDENCE IS LOW WITH MODEL VARIABILITY SUGGESTING
VARIOUS SOLUTION. WE WILL CONTINUE TO MENTION FOG IN THE FORECAST
BUT NO HEADLINES ATTM. COORDINATION WITH RNK.
AS OF 800 PM...MESO ANALYSIS HAS WAVY BACKDOOR FRONT DROPPING
THROUGH OUR EASTERN FORECAST AREA (FA) ALONG WITH A SLIGHT UPTICK IN
MAINLY SHOWERS...SOME WITH HEAVY RAIN. WE/VE ADJUSTED OUR WIND
FORECAST TO BRING THE FRONT...ON OUR EASTERN FLANK...TO THE NC/SC
STATE LINE. IT APPEARS THE RAP MODEL IS HANDLING THIS FEATURE THE
BEST. OTHERWISE SCATTERED SHOWERS CONTINUE...MOST NUMEROUS IN THE NC
FOOTHILLS AND THE UPSTATE OF SC. THE QUESTION IS WHAT TO DO WITH THE
WATER VAPOR IMAGERY WAVE LIFTING FROM SOUTHERN MISSISSIPPI...TO THE
NE? IN THE VERY SHORT TERM WE ARE IN GOOD SHAPE...BUT MAY HAVE TO
SLOW DOWN THE POP DECREASING TREND A BIT...PARTICULARLY FAR SOUTH
AND EAST FA. TEMPERATURES STILL APPEAR ON TARGET.
AS OF 500 PM...MESO SCALE MODELS SHOWING POTENTIAL FLAIR-UP...OR AN
UPTICK IN CONVECTIVE POTENTIAL...ACROSS OUR EASTERN AND SOUTHERN
FORECAST AREA (FA). SURFACE BASED CAPES ARE INCHING UPWARD WITH SOME
BREAKS IN THE CLOUDS...HOWEVER NOT A LARGE INCREASE IN CONVECTION
HAS YET BEEN NOTED. WE WILL CONTINUE TO RUN THE COURSE WITH A MEDIUM
RANGE POP INTO THE EARLY EVENING...BANKING ON OVERALL CLOUDS (BIG
PICTURE) TO KEEP THINGS AT BAY. THIS WAS PRESENTED IN THE EARLIER
FORECAST...AND ONLY MINOR CHANGES ARE NEEDED. MINOR ADJUSTMENTS ON
TEMPERATURES AS WELL TO MIRROR CURRENT TRENDS.
AS OF 220 PM...SCATTERED SHOWERS CONTINUE TO DEVELOP ACROSS THE
AREA...MAINLY ASSOCIATED WITH THE DEEPER MOISTURE AND WEAK
INSTABILITY ALONG/EAST OF I-85. POPS WILL RANGE FROM LOW CHANCE
ACROSS THE NORTH TO HIGH CHANCE ACROSS THE SOUTH INTO THE EVENING
HOURS. AS EXPECTED...WIDESPREAD CLOUD COVER HAS LIMITED
DESTABILIZATION ACROSS THE AREA...BUT THANKS TO SOME BREAKS IN THE
OVC...CAPE VALUES ARE EDGING CLOSER TO 1000 J/KG ACROSS THE SOUTHERN
ZONES PER LATEST SPC MESOANALYSIS. EXPECT THUNDERSTORMS TO DEVELOP
AND GRADUALLY EXPAND IN COVERAGE THIS AFTERNOON...BUT STORMS SHOULD
REMAIN ISOLATED TO WIDELY SCATTERED. DEEP LAYER BULK SHEAR REMAINS
QUITE HIGH FOR THIS TIME OF YEAR (AROUND 40 KT)...SO IF CAPE VALUES
CAN NUDGE A LITTLE CLOSER TO 2000 J/KG...WE COULD SEE AN ISOLATED
SEVERE THREAT ACROSS OUR SOUTHERN ZONES. HOWEVER...THIS DOESN/T
APPEAR LIKELY.
CONVECTION WILL GRADUALLY DIMINISH THIS EVENING...AS MID/UPPER LEVEL
DRY AIR ADVECTION OVERSPREADS THE AREA...AND FORCING REMAINS
RELATIVELY WEAK. DEPENDING UPON HOW QUICKLY THE HIGHER CLOUDS
DISSIPATE...WE COULD BE SETTING UP FOR A DENSE FOG EVENT ACROSS
PORTIONS OF THE CWA LATE TONIGHT.
BY MONDAY MORNING...THE UPPER JET AXIS SHIFTS TO THE APPALACHIANS.
THIS RESULTS IN SHUNTING OF THE DEEPER MOISTURE AND BETTER FORCING
TOWARD THE COAST. QPF RESPONSE IS THEREFORE LIMITED ACROSS OUR AREA
IN MOST MODEL SOLUTIONS. IN FACT...THE LEAST RUNS OF THE SREF AND
ECMWF ARE PRACTICALLY BONE DRY IN OUR CWA. HOWEVER...THE UPPER
TROUGH AXIS WILL REMAIN TO OUR WEST...WHILE DRYING ALOFT SHOULD
ALLOW FOR MUCH MORE SUN TOMORROW THAN WE HAVE SEEN TODAY. THIS
SHOULD RESULT IN MODERATE INSTABILITY DEVELOPING BY AFTERNOON.
ALTHOUGH THIS MAY SUPPORT SCATTERED DIURNAL CONVECTION...IT DOES
APPEAR THAT WE NEED TO BACK OFF THE LIKELY POPS WE HAVE BEEN
ADVERTISING FOR MONDAY. MORE SUN ON MONDAY WILL ALLOW FOR WARMER MAX
TEMPS...BUT THESE SHOULD STILL BE ABOUT A CATEGORY BELOW NORMAL
UNDER THE DEEP LONG WAVE TROUGH.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 130 PM SUNDAY...AN UPPER JETLET WILL BISECT THE FORECAST AREA
MON NIGHT THROUGH TUE...WITH UPPER DIVERGENCE FOCUSED MAINLY OVER
OUR ERN PIEDMONT. THE BEST CHC POPS WILL BE OVER THE ERN PART OF THE
FORECAST AREA IN THE DEEPER MOISTURE AND ALSO OVER THE NRN MTNS WITH
THE ARRIVAL OF A MORE POTENT VORTICITY LOBE IN THE TROUGH AXIS TO
THE WEST. TUE AFTN MAX TEMPS SHOULD RISE A CATEGORY OR SO ABOVE MON
VALUES.
THE NRN TIER SHORTWAVE WILL LIFT NE OF THE REGION INTO WED...BUT
WITH ADDITIONAL UPSTREAM TROUGHINESS CARVING OUT AS THE NEXT WAVE
MOVES OVER THE MS RIVER TOWARD THE SE. PROFILES APPEAR QUITE A BIT
DRIER AHEAD OF THIS SYSTEM...SO WILL FEATURE MAINLY DIURNALLY DRIVEN
ISOLD TSTMS...WITH LOCAL MAXIMA OF COVERAGE ALONG THE MTN RIDGES AND
THE EXTREME SE PIEDMONT. MAX TEMPS SHOULD GAIN ANOTHER DEGREE OR SO
OVER TUE VALUES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 145 PM SUNDAY...SHORTWAVE RIDGING SHOULD RETURN FROM THE WEST
THU THROUGH FRI...AND POSSIBLY LINGER INTO NEXT WEEKEND. WEAK HIGH
PRESSURE WILL ALSO BUILD DOWN FROM THE N THROUGH THE PERIOD. WILL
FEATURE MAX TEMPS A TOUCH WARMER THAN PREVIOUSLY FOR THU THROUGH SAT
GIVEN THE BETTER INSOLATION UNDER THE SHALLOW UPPER RIDGE. EXPECT
LITTLE MORE THAN DIURNAL ISOLD WEAK CONVECTION...WITH COVERAGE BEST
ALONG THE MTN RIDGES.
MODEL UNCERTAINTY BUILDS THROUGH NEXT WEEKEND...WITH THE ECM
FEATURING A SHORTWAVE DEVELOPING OVER THE MID MS RIVER VALLEY ON SAT
WHICH IT MOVES INTO THE SRN APPALACHIANS ON SUNDAY. THE GFS PHASES
THIS SYSTEM BACK INTO THE NRN STREAM AND KEEPS A FLAT UPPER RIDGE IN
PLACE THROUGH SUNDAY. THE CMC/GEFS AND HPC LEAN TOWARD THE ECM
SOLUTION...SO WILL ADVERTISE SLOWLY RISING CHC POPS THROUGH LATE
SUNDAY ALONG WITH COOLER THAN MOS TEMPS.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AT KCLT...BACK DOOR COLD FRONT HAS SHIFTED WINDS OVER TO THE
NORTHEAST AND BROUGHT CEILINGS DOWN. CONVECTION HAS BEEN INCREASING
NEAR THIS BOUNDARY/CDFNT...BUT STILL APPEARS SHALLOW WITH LITTLE OR
NO LIGHTNING...SO FAR. WE WILL CONTINUE SCT SHOWERS FOR A FEW MORE
HOURS THEN EASE BACK TO VICINITY AS FRONT SAGS SOUTH. WE BROUGHT
CEILINGS DOWN TO MVFR AND ALLOWED SOME LIGHT FOG TO FORM. IF CLOUDS
WERE TO BREAK FOG WOULD BE MORE OF A PROBLEM...BUT DO NOT SEE THAT
AT THE MOMENT. WE CONTINUE TO REMAIN IN THE RIGHT ENTRANCE REGION OF
A STRONG JET ACROSS THE APPALACHIANS MONDAY...AS A RESULT AFTERNOON
CONVECTION STILL IN PLAY...ESPECIALLY NEAR THE OLD FRONTAL BOUNDARY.
ELSEWHERE...CEILING AND VISIBILITES ARE ALL OVER THE MAP WITH OUR
NORTHERN TAF SITES CAUGHT IN MVFR CIGS ON THE NORTH SIDE OF THE
FRONT...AND CONVECTION HITTING/OR NEAR/ OUR SOUTHERN TAF SITES.
OVERALL WE HAVE TRENDED ALL TAF SITES DOWN...IN PCPN POTENTIAL...
AS THE NIGHT WEARS ON. WE ARE MORE CONFIDENT IN THAT FORECAST FOR
ASHEVILLE...AND IF CLOUDS THIN ENOUGH FOG WILL BECOME A PROBLEM.
AT KCLT AND ELSEWHERE...WILL CONTINUE TREND OF SHOWERS IN VICINITY
OF SITES INTO THE EVENING. SHORT RANGE MODELS CONTINUE TO TRY WITH
A LARGE UPTICK IN CONVECTION...BUT CLOUDS AT LEAST IN THE VERY NEAR
TERM ARE HOLDING THINGS BACK. WE WILL FOLLOW THAT CURRENT TREND.
OUTLOOK...SCATTERED CONVECTION IS EXPECTED TO DEVELOP ACROSS THE
AREA MONDAY AFTERNOON. A WEAK STATIONARY BOUNDARY WILL LINGER ACROSS
THE REGION THROUGH THE EARLY WEEK. SFC LOWS MAY TRACK ALONG THE
FRONT...SUPPORTING PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH
TUESDAY. IN ADDITION...THE FORMATION OF LOW CLOUDS AND FOG IS
POSSIBLE EACH MORNING...ESPECIALLY NEAR AREAS OF RECENT RAINFALL.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...JDL/STUREY
SHORT TERM...HG
LONG TERM...HG
AVIATION...JDL/STUREY
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1025 PM CDT SUN AUG 19 2012
.UPDATE...ADDED AVIATION SECTION FOR 06Z TAF`S.
&&
.AVIATION...BNA/CKV/CSV...HIGH PRESSURE BUILDING INTO MIDDLE
TENNESSEE THE NEXT 24 HRS AS A DRY, COOLER AIR MASS PUSHES IN.
LOOK FOR VFR WX THE NEXT 24 HRS.
&&
.PREV DISCUSSION... /ISSUED 947 PM CDT SUN AUG 19 2012/
UPDATE...SATELLITE PICS SHOW PATCHES OF MID CLOUDS SWEEPING INTO
NORTHWESTERN MIDDLE TENNESSEE ON THE WINGS OF AN UPPER LEVEL
SHORTWAVE. LATEST RUC MODEL SHOWS A GOOD DOSE OF 700-500MB MOISTURE
PUSHING ACROSS THE AREA FOR THE REST OF THE NIGHT, AND CAN`T RULE
OUT A FEW LIGHT SHOWERS, ESPECIALLY WEST. HOWEVER, SINCE 1000-850MB LAYER
REMAINS QUITE DRY, DON`T HAVE ENOUGH CONFIDENCE TO MENTION EVEN
SPRINKLES IN THE FORECAST AT THIS POINT. SO, WILL LEAVE OUR DRY
OVERNIGHT FORECAST IN PLACE.
HAVE UPDATED VARIOUS GRID PARAMETERS TO AGREE MORE CLOSELY WITH
CURRENT TRENDS AND LATEST RUC SOLUTION. HOWEVER, HAVE LEFT MIN
TEMPS AS THEY ARE FOR NOW.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
ROSE
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
947 PM CDT SUN AUG 19 2012
.UPDATE...SATELLITE PICS SHOW PATCHES OF MID CLOUDS SWEEPING INTO
NORTHWESTERN MIDDLE TENNESSEE ON THE WINGS OF AN UPPER LEVEL
SHORTWAVE. LATEST RUC MODEL SHOWS A GOOD DOSE OF 700-500MB MOISTURE
PUSHING ACROSS THE AREA FOR THE REST OF THE NIGHT, AND CAN`T RULE
OUT A FEW LIGHT SHOWERS, ESPECIALLY WEST. HOWEVER, SINCE 1000-850MB LAYER
REMAINS QUITE DRY, DON`T HAVE ENOUGH CONFIDENCE TO MENTION EVEN
SPRINKLES IN THE FORECAST AT THIS POINT. SO, WILL LEAVE OUR DRY
OVERNIGHT FORECAST IN PLACE.
HAVE UPDATED VARIOUS GRID PARAMETERS TO AGREE MORE CLOSELY WITH
CURRENT TRENDS AND LATEST RUC SOLUTION. HOWEVER, HAVE LEFT MIN
TEMPS AS THEY ARE FOR NOW.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
19
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
551 PM CDT SAT AUG 18 2012
.UPDATE...
QUICK UPDATE TO REMOVE HALL...CHILDRESS AND COTTLE COUNTIES FROM
THE SEVERE THUNDERSTORM WATCH. OVERALL...STORM INTENSITY HAS BEEN
RATHER TAME...THOUGH A FEW CELLS DO OCCASIONALLY PULSE UP. IN
ADDITION...A SMALL CLUSTER OF STORMS COULD GENERATE GUSTY WINDS AS
THEY MOVE THROUGH THE SOUTHEASTERN ZONES OVER THE NEXT HALF HOUR
TO HOUR. UPDATED PRODUCTS HAVE BEEN SENT.
&&
.PREV DISCUSSION... /ISSUED 339 PM CDT SAT AUG 18 2012/
SHORT TERM...
WELL-DEFINED OUTFLOW BOUNDARY/COMPOSITE COLD FRONT WAS MOVING
SOUTHWEST INTO CHILDRESS AND HALL COUNTIES JUST NORTH OF A SURFACE
TROUGH STRETCHING FROM NEAR DIMMITT ESE TO SWEARINGEN. THE TRUE COLD
FRONT OF INTEREST THAT IS PROGGED TO DROP HIGHS BELOW NORMAL ON
SUNDAY /UNDER MOSTLY SUNNY SKIES!/ WAS FOUND DIVING SOUTH ACROSS WRN
KANSAS AND ERN COLORADO. BRUNT OF THE PRECIP POTENTIAL WILL BE
RELEGATED TO THE PRE-FRONTAL BOUNDARIES CURRENTLY CONVECTING ACROSS
THE NRN HALF OF THE CWA. ALTHOUGH WIND SHEAR IS WEAK THUS FAR...THIS
WILL IMPROVE AS THE AFTERNOON AND EARLY EVENING WEAR ON COURTESY OF
A SHORTWAVE TROUGH AND ASSOCIATED WIND MAX APPROACHING IN NORTHWEST
FLOW. EVEN WITH MLCAPES GENERALLY AOB 1000 J/KG...THIS IMPROVING
LIFT SHOULD SECURE A WINDOW FOR ORGANIZED SEVERE STORMS MAINLY IN
THE FORM OF SMALL SEGMENTS OR LINES WITH DMGG WINDS THE GREATEST
THREAT BEFORE INTENSITY AND STORM COVERAGE WANE BY LATE EVENING.
CURRENT SVR WATCH CAPTURES THIS THREAT WELL...BUT MAY REQUIRE
EXPANSION SWWD SHOULD TRENDS WARRANT. A FEW HI-RES MODELS SUCH AS
THE TTU WRF AND HRRR DO INDICATE SUCH A SCENARIO FOR LUBBOCK AND
POINTS SOUTHWEST...SO THIS WILL BE MONITORED CLOSELY BY THE ONCOMING
SHIFT. OTHERWISE...FROPA WILL OCCUR AFTER MIDNIGHT FOLLOWED BY
DIMINISHING POPS. MOIST POST-FRONTAL UPSLOPE TOMORROW AFTN IN ERN NM
AND ADJACENT COUNTIES OF THE TX SOUTH PLAINS STILL APPEARS
REASONABLE FOR SLIGHT CHANCE POPS IN OUR SWRN COUNTIES...HOWEVER THE
NAM LOOKS MUCH TOO BULLISH WITH QPF IN SUCH A REGIME AND IS LARGELY
BEING DISMISSED
LONG TERM...
NNW FLOW ALOFT IS EXPECTED ON MONDAY. HIGH AMPLITUDE RIDGE WILL
SPAN FROM NWRN MEXICO UP TO NORTHERN ALBERTA. OUT EAST...MATURE LOW
WILL BE SITUATED OVER THE SRN PART OF HUDSON BAY WITH AN EMBEDDED
SHORTWAVE DUE INTO THE CENTRAL PLAINS EARLY ON TUESDAY ALTHOUGH THE
BEST ENERGY ASSOCIATED WITH THIS SYSTEM WILL LIKELY REMAIN NORTHEAST
OF THE REGION. BY MID WEEK...THE RIDGE WILL BEGIN TO MOVE EASTWARD
AND FLATTEN WITH SOME HINTS IN BOTH THE GFS AND ECM ABOUT A BIT OF A
DISTURBANCE PASSING TO OUR NORTH ON THURSDAY. WHILE THE ECM
SOLUTION WOULD BE MORE FAVORABLE INTO BRINGING A FRONT INTO THE
REGION...AND PRECIPITATION...THE GFS HAS MORE CLOSELY PARALLELED
REALITY FOR THE PAST WEEK AND THUS WILL TREND THE FORECAST IN THAT
DIRECTION.
GIVEN NWP PERFORMANCE AS OF LATE WRT QPF AM NOT COMPLETELY CONVINCED
THAT WE WILL SEE AS MUCH RAIN ACROSS THE REGION AS PREVIOUSLY
THOUGHT...BUT HAVE ELECTED ONLY TO MAKE A DOWNWARD TREND OF MONDAY
NIGHT POPS. LIKE TODAY...VIRTUALLY EVERY MODEL CONVECTS BUT PRECIP
HAS BEEN HARD TO COME BY. AS PREVIOUSLY MENTIONED...SHORTWAVE
PASSES TO OUR NORTH SOMETIME ON THURSDAY BUT AGAIN...CONFIDENCE IN
MEANINGFUL RAINFALL IS TOO LOW FOR MENTION IN THE WX GRIDS ATTM.
GIVEN THAT...MOST OF THE EXTENDED LOOKS DRY ALTHOUGH WE WOULD LOVE
TO BE WRONG ABOUT THAT.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 61 83 57 85 58 / 30 10 10 20 30
TULIA 63 83 61 85 60 / 40 10 10 10 30
PLAINVIEW 64 82 61 88 63 / 50 10 10 10 30
LEVELLAND 66 83 61 89 63 / 50 20 10 10 30
LUBBOCK 67 84 62 90 65 / 50 20 10 10 30
DENVER CITY 66 84 62 93 63 / 40 20 10 10 20
BROWNFIELD 66 84 62 93 65 / 50 20 10 10 20
CHILDRESS 68 87 64 91 64 / 40 10 0 10 30
SPUR 68 86 65 94 68 / 50 20 10 10 20
ASPERMONT 70 89 67 97 68 / 50 20 10 10 20
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33/23
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
339 PM CDT SAT AUG 18 2012
.SHORT TERM...
WELL-DEFINED OUTFLOW BOUNDARY/COMPOSITE COLD FRONT WAS MOVING
SOUTHWEST INTO CHILDRESS AND HALL COUNTIES JUST NORTH OF A SURFACE
TROUGH STRETCHING FROM NEAR DIMMITT ESE TO SWEARINGEN. THE TRUE COLD
FRONT OF INTEREST THAT IS PROGGED TO DROP HIGHS BELOW NORMAL ON
SUNDAY /UNDER MOSTLY SUNNY SKIES!/ WAS FOUND DIVING SOUTH ACROSS WRN
KANSAS AND ERN COLORADO. BRUNT OF THE PRECIP POTENTIAL WILL BE
RELEGATED TO THE PRE-FRONTAL BOUNDARIES CURRENTLY CONVECTING ACROSS
THE NRN HALF OF THE CWA. ALTHOUGH WIND SHEAR IS WEAK THUS FAR...THIS
WILL IMPROVE AS THE AFTERNOON AND EARLY EVENING WEAR ON COURTESY OF
A SHORTWAVE TROUGH AND ASSOCIATED WIND MAX APPROACHING IN NORTHWEST
FLOW. EVEN WITH MLCAPES GENERALLY AOB 1000 J/KG...THIS IMPROVING
LIFT SHOULD SECURE A WINDOW FOR ORGANIZED SEVERE STORMS MAINLY IN
THE FORM OF SMALL SEGMENTS OR LINES WITH DMGG WINDS THE GREATEST
THREAT BEFORE INTENSITY AND STORM COVERAGE WANE BY LATE EVENING.
CURRENT SVR WATCH CAPTURES THIS THREAT WELL...BUT MAY REQUIRE
EXPANSION SWWD SHOULD TRENDS WARRANT. A FEW HI-RES MODELS SUCH AS
THE TTU WRF AND HRRR DO INDICATE SUCH A SCENARIO FOR LUBBOCK AND
POINTS SOUTHWEST...SO THIS WILL BE MONITORED CLOSELY BY THE ONCOMING
SHIFT. OTHERWISE...FROPA WILL OCCUR AFTER MIDNIGHT FOLLOWED BY
DIMINISHING POPS. MOIST POST-FRONTAL UPSLOPE TOMORROW AFTN IN ERN NM
AND ADJACENT COUNTIES OF THE TX SOUTH PLAINS STILL APPEARS
REASONABLE FOR SLIGHT CHANCE POPS IN OUR SWRN COUNTIES...HOWEVER THE
NAM LOOKS MUCH TOO BULLISH WITH QPF IN SUCH A REGIME AND IS LARGELY
BEING DISMISSED
&&
.LONG TERM...
NNW FLOW ALOFT IS EXPECTED ON MONDAY. HIGH AMPLITUDE RIDGE WILL
SPAN FROM NWRN MEXICO UP TO NORTHERN ALBERTA. OUT EAST...MATURE LOW
WILL BE SITUATED OVER THE SRN PART OF HUDSON BAY WITH AN EMBEDDED
SHORTWAVE DUE INTO THE CENTRAL PLAINS EARLY ON TUESDAY ALTHOUGH THE
BEST ENERGY ASSOCIATED WITH THIS SYSTEM WILL LIKELY REMAIN NORTHEAST
OF THE REGION. BY MID WEEK...THE RIDGE WILL BEGIN TO MOVE EASTWARD
AND FLATTEN WITH SOME HINTS IN BOTH THE GFS AND ECM ABOUT A BIT OF A
DISTURBANCE PASSING TO OUR NORTH ON THURSDAY. WHILE THE ECM
SOLUTION WOULD BE MORE FAVORABLE INTO BRINGING A FRONT INTO THE
REGION...AND PRECIPITATION...THE GFS HAS MORE CLOSELY PARALLELED
REALITY FOR THE PAST WEEK AND THUS WILL TREND THE FORECAST IN THAT
DIRECTION.
GIVEN NWP PERFORMANCE AS OF LATE WRT QPF AM NOT COMPLETELY CONVINCED
THAT WE WILL SEE AS MUCH RAIN ACROSS THE REGION AS PREVIOUSLY
THOUGHT...BUT HAVE ELECTED ONLY TO MAKE A DOWNWARD TREND OF MONDAY
NIGHT POPS. LIKE TODAY...VIRTUALLY EVERY MODEL CONVECTS BUT PRECIP
HAS BEEN HARD TO COME BY. AS PREVIOUSLY MENTIONED...SHORTWAVE
PASSES TO OUR NORTH SOMETIME ON THURSDAY BUT AGAIN...CONFIDENCE IN
MEANINGFUL RAINFALL IS TOO LOW FOR MENTION IN THE WX GRIDS ATTM.
GIVEN THAT...MOST OF THE EXTENDED LOOKS DRY ALTHOUGH WE WOULD LOVE
TO BE WRONG ABOUT THAT.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 61 83 57 85 58 / 30 10 10 20 30
TULIA 63 83 61 85 60 / 40 10 10 10 30
PLAINVIEW 64 82 61 88 63 / 50 10 10 10 30
LEVELLAND 66 83 61 89 63 / 50 20 10 10 30
LUBBOCK 67 84 62 90 65 / 50 20 10 10 30
DENVER CITY 66 84 62 93 63 / 40 20 10 10 20
BROWNFIELD 66 84 62 93 65 / 50 20 10 10 20
CHILDRESS 68 87 64 91 64 / 40 10 0 10 30
SPUR 68 86 65 94 68 / 50 20 10 10 20
ASPERMONT 70 89 67 97 68 / 50 20 10 10 20
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
93/26
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1153 PM CDT FRI AUG 17 2012
.DISCUSSION...
LOOK FOR VFR CONDITIONS TO CONTINUE ACROSS WEST CENTRAL TEXAS FOR
THE NEXT 24 HOURS. SEE AVIATION BELOW FOR DETAILS.
&&
.AVIATION...
SHOWERS AND THUNDERSTORMS ARE POSSIBLE AGAIN ACROSS WEST CENTRAL
TEXAS TOMORROW AFTERNOON AND EVENING. MODELS INDICATE DEVELOPMENT
WILL BEGIN AROUND 18Z AND CONTINUE UNTIL AROUND 06Z TOMORROW
EVENING. MEANWHILE...DISSIPATING SHOWERS WILL LINGER ACROSS MAINLY
THE NORTHERN EDWARDS PLATEAU AND NORTHWEST HILL COUNTY FOR A
COUPLE MORE HOURS. HOWEVER...IMPACT TO ANY OF OUR SOUTHERN
TERMINALS WILL BE NIL. EXPECT SOUTH TO SOUTHEAST SURFACE WINDS
DURING THE NEXT 24 HOURS AT 10 KNOTS OR LESS.
HUBER
&&
.PREV DISCUSSION... /ISSUED 643 PM CDT FRI AUG 17 2012/
DISCUSSION...
SEE AVIATION SECTION.
AVIATION...
AVIATION FORECAST FOR THIS PACKAGE LARGELY REVOLVES AROUND PLACEMENT
OF CONVECTION AND ASSOCIATED EFFECTS. ONE OF THE MAIN CHANGES WITH
THE 00Z PACKAGE IS TO REMOVE/REDUCE LONG-PERIOD /UP TO 20 HOURS AT
KSJT/ VCTS GROUPS. MOST OF THE SHOWERS AND THUNDERSTORMS THIS
EVENING HAVE BEEN ACROSS THE AREA SOUTH OF INTERSTATE 20 AND NORTH
OF INTERSTATE 10...WITHIN SUBTROPICAL MOISTURE PLUME. OVERALL
STEERING FLOW IS WEAK...BUT THE GENERAL PROPAGATION AND NEW
DEVELOPMENT HAS BEEN MOSTLY TO THE SOUTH-SOUTHEAST. FORECAST
PLACEMENT OF CONVECTION IS VERY PROBLEMATIC FOR THE NEXT 24 HOURS.
BELIEVE MOST OF THE CURRENT CONVECTION...WHICH IS SURFACE BASED AND
DIURNALLY DRIVEN...WILL DISSIPATE EARLY TONIGHT. WHILE REDEVELOPMENT
OF CONVECTION CANNOT BE RULED OUT OVERNIGHT...THE CHANCE APPEARS LOW
ENOUGH TO PRECLUDE MENTIONING IN THE AREA TAFS. A BETTER CHANCE OF
REDEVELOPMENT WILL BE DURING THE DAY SATURDAY WITH DIURNAL HEATING
AND DESTABILIZATION OF THE MOIST AIRMASS. WILL HAVE MULTIPLE OUTFLOW
BOUNDARIES ACROSS THE AREA WHICH WHERE CONVECTION MAY INITIATE. WILL
CARRY VCTS AFTER 16Z OR 17Z AT MOST IF NOT ALL TAF SITES. A FEW
STRONGER STORMS WITH GUSTS OVER 35 KT WILL BE POSSIBLE. LOCALIZED
REDUCTIONS IN VISIBILITY AND CEILING ARE ALSO POSSIBLE IN THE HEAVY
RAINFALL WHICH ACCOMPANIES THE CONVECTION. WINDS TONIGHT WILL BE
VARIABLE AT SPEEDS UNDER 10 KT. ON SATURDAY...WINDS OUTSIDE OF
CONVECTIVE INFLUENCES WILL BE MOSTLY SOUTHEAST TO SOUTH AT 5-10 KT.
PREV DISCUSSION... /ISSUED 312 PM CDT FRI AUG 17 2012/
SHORT TERM...
FOR THIS AFTERNOON INTO THIS EVENING...HAVE RAISED POPS A LITTLE
THROUGH THE REST OF THE CONCHO VALLEY. HIGH RESOLUTION RAP SOLUTION
HAS CONVECTION ACROSS THE CONCHO VALLEY THROUGH THE AFTERNOON AND
THEN DEVELOPS MORE CONVECTION ACROSS THE BIG COUNTRY. THE RAP HAS
MORE BROAD CONVECTION ACROSS THE AREA WHILE THE TEXAS TECH 3KM WRF
HAS THE ACTIVITY TOO FAR NORTH. TAKING A LOOK AT SHOWERS AND
THUNDERSTORMS THAT ARE ALREADY FORMING...THE HIGH RESOLUTION RAP
MODEL LOOKS TO BE A BETTER SOLUTION. HAVE NOT CHANGED MUCH THROUGH
THE REST OF TONIGHT AND TOMORROW. MOST OF ACTIVITY LOOKS TO BE
SCATTERED AS IT WILL BE DRIVEN BY MESOSCALE PROCESSES.
REIMER
LONG TERM...
PRECIPITATION CHANCES WILL CONTINUE THROUGH THE FIRST PART OF THE
EXTENDED FORECAST. A WEAK COLD FRONT THAT IS CURRENTLY STALLED
ACROSS WEST CENTRAL TEXAS WILL REMAIN IN THE VICINITY OF THE AREA
AND BECOME FAIRLY DIFFUSE BY LATE SATURDAY. REGARDLESS...THE FRONT
WILL SERVE AS A FOCUS FOR CONTINUED SHOWERS AND THUNDERSTORMS ACROSS
ALL OF THE REGION SATURDAY NIGHT. SATURDAY...A SHORTWAVE TROUGH WILL
SWING ACROSS THE PLAINS...ALONG THE SOUTHERN PERIPHERY OF THE MAIN
UPPER LEVEL TROUGH THAT IS FORECAST TO BE LOCATED OVER THE MIDWEST.
THIS WILL SEND A REINFORCING SHOT OF SURFACE HIGH PRESSURE DOWN THE
PLAINS AND INTO WEST CENTRAL TEXAS ON SUNDAY. THIS WILL RESULT IN
DECREASING RAIN CHANCES FROM NORTH TO SOUTH THROUGHOUT THE DAY
SUNDAY. I COOLED HIGH TEMPERATURES SUNDAY BY A DEGREE OR TWO...GIVEN
THE EXPECTED CLOUD COVER AND RAINFALL...AND THESE MAY NEED TO
EVENTUALLY BE LOWERED EVEN MORE. SUNDAY NIGHT...RAIN CHANCES WILL BE
CONFINED TO THE CONCHO VALLEY AND AREAS TO THE SOUTH. ALTHOUGH A FEW
STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE SATURDAY NIGHT
THROUGH SUNDAY...THE MAIN THREAT IS THE POTENTIAL FOR LOCALLY HEAVY
RAINFALL.
BEYOND SUNDAY...A SLOW WARMING TREND IS EXPECTED...WITH TEMPERATURES
BACK INTO THE MID 90S BY MID WEEK. MODELS ARE STILL INDICATING A
DISTURBANCE EMBEDDED IN THE NORTHWEST FLOW ALOFT...DROPPING THROUGH
THE TEXAS PANHANDLE MONDAY NIGHT OR TUESDAY. THIS WILL LIKELY RESULT
IN AN MCS DEVELOPING ACROSS THE PANHANDLE AND THEN MOVING SOUTHEAST.
AT THIS TIME...CONFIDENCE IS NOT HIGH ENOUGH IN THIS FEATURE
REACHING WEST CENTRAL TEXAS...SO I HAVE LEFT POPS BELOW 15 PERCENT.
DANIELS
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 73 95 71 90 68 / 20 50 50 30 10
SAN ANGELO 74 95 72 91 69 / 30 40 50 40 20
JUNCTION 74 97 72 92 70 / 20 30 40 40 20
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
HUBER
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
150 AM EDT SAT AUG 18 2012
.SYNOPSIS...
A COLD FRONT WILL CONTINUE HEADING SOUTHEAST THROUGH...AND THEN
OUT OF THE REGION TONIGHT. DEEPENING LOW PRESSURE...ANCHORED OVER
SOUTHEAST CANADA...WILL EVOLVE ACROSS THE EASTERN U.S. FOR THE
WEEKEND INTO THE FIRST HALF OF NEXT WEEK. A SERIES OF DISTURBANCES
EMBEDDED WITHIN THE UPPER LOW WILL KEEP
UNSETTLED...SHOWERY...CLOUDY...COOL CONDITIONS ACROSS MUCH OF THE
AREA UNTIL TUESDAY...WHEN DRIER CONDITIONS ALONG WITH SEASONABLE
TEMPERATURES ARE EXPECTED.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 120 AM EDT SATURDAY...
SCATTERED PATCHES OF -RA MOVING THROUGH FAR SW VA TOWARD THE NEW
RIVER VALLEY ASSOCIATED WITH DISSIPATING FRONTAL BOUNDARY. THIS
ACTIVITY WILL LIKELY MAKE VERY LITTLE PROGRESS PAST THE NEW RIVER
VALLEY REGION BEFORE COMPLETELY DISSIPATING. HAVE HELD ONTO TO VERY
LOW POPS FOR -SHRA GENERALLY WEST OF LWB-ROA FOR A COUPLE HOURS
LONGER THAN PREVIOUSLY INDICATED. OTHERWISE...ONLY MINOR
MODIFICATIONS TO T/TD GRIDS TO BRING MORE INTO LINE WITH CURRENT
OBS...WHICH IN GENERAL WERE A COUPLE OF DEGREES COOLER THAN PLANNED
AS A RESULT OF LESS HEATING THAN ANTICIPATED FRIDAY WITH EXTENSIVE
MID CLOUDS.
AS OF 934 PM EDT FRIDAY...
ISOLATED TO SCATTERED SHOWERS ASSOCIATED WITH A COLD FRONT HAVE
ENTERED THE FAR SOUTHWEST PORTION OF THE FORECAST AREA. LITTLE IF
ANY PRECIPITATION WAS OCCURRING ELSEWHERE. BELIEVE THE REMAINDER
OF THE NIGHT WILL WELCOME THE ISOLATED TO SCATTERED SHOWERS ALONG
THE FRONT AS IT PROGRESSES EAST OF THE CREST OF THE BLUE RIDGE.
AROUND DAYBREAK SATURDAY...GUIDANCE SUGGEST A DISTURBANCE WILL BE
RIDING ALONG THE FRONT THROUGH THE CAROLINAS. THIS MAY HAVE THE
IMPACT OF INCREASING THE COVERAGE OF SHOWERS ACROSS SOUTHSIDE
VIRGINIA AND NEIGHBORING SECTIONS OF NORTH CAROLINA AT THIS TIME.
HAVE ADJUSTED PERCENTAGE OF PRECIPITATION CHANCES AND WEATHER
GRIDS TO REFLECT THIS THINKING. HAVE ALSO TWEAKED HOURLY GRIDS FOR
TEMPERATURE...DEW POINT...AND WIND BASED UPON CURRENT CONDITIONS
AND EXPECTED TRENDS INTO EARLY SATURDAY MORNING.
AS OF 715 PM EDT FRIDAY...
HAVE TRIMMED BACK PRECIPITATION CHANCES BASED UPON THE LATEST
TRENDS OF KFCX AND OTHER NEIGHBORING 88D RADARS. FIRST LINE OF
CONVECTION WILL BE EAST OF THE FORECAST AREA BY 800 PM. NEXT LINE
OF PRECIPITATION WILL BE ASSOCIATED WITH THE ACTUAL COLD FRONT.
RADARS ARE SHOWING AN ISOLATED TO SCATTERED COVERAGE WITH THIS
ACTIVITY. ANTICIPATE COVERAGE TO BE OF A SIMILAR OR LESS COVERAGE
AS THE FRONT HEADS EAST AND ENCOUNTERS THE RELATIVELY STABLE AREA
ACROSS THE REGION...ESPECIALLY WITH THE SOON LOSS OF SUNSHINE.
HAVE ALSO ADJUSTED TEMPERATURE...DEW POINT...AND SKY COVER BASED
UPON THE LATEST OBSERVATIONS AND EXPECTED TRENDS THROUGH THE
EVENING.
AS 310 PM EDT FRIDAY...
SFC COLD FRONT LOCATED TO OUR WEST FROM WESTERN PENNSYLVANIA
SOUTHWARD TO EASTERN KY. THIS FRONT WILL MOVE SOUTHEAST TONIGHT INTO
SATURDAY. CONVECTION COVERAGE SHOULD INCREASE LATE THIS AFTERNOON
INTO TONIGHT...DUE TO COMBINATION OF DIFFERENTIAL HEATING EFFECTS
AND THE APPROACH OF COLD FRONT/MID-LEVEL SHORT WAVE TROUGH. AT THIS
TIME...REGIONAL WSR-88D IMAGES SHOWED SHOWERS AND ISOLATED
THUNDERSTORMS MOVING EAST ACROSS WESTERN PORTIONS OF CWA. LOOKS LIKE
THE BEST INSTABILITY IS JUST AHEAD OF THE CLOUD DECK. SPC RECENTLY
REMOVED MUCH OF THE AREA FROM THEIR SLIGHT RISK...AND THIS SEEMS
REASONABLE...ESPECIALLY IN LIGHT OF THE WEAK SHEAR OVER THE REGION.
AN ISOLATED STRONG TO SEVERE THUNDERSTORM MAY BE POSSIBLE THIS
EVENING WITH MAIN THREAT HEAVY RAINS AND GUSTY WINDS.
THUNDERSTORMS AND SHOWERS SHOULD WANE/DIMINISH TONIGHT AS THE
UPPER SHORT WAVE SHEARS OUT AND THE MAIN DYNAMICS MOVE TOWARD NEW
ENGLAND. ANOTHER SHORTWAVE POISED THE MOVE ACROSS THE UPPER
MIDWEST/NORTHERN PLAINS OVERNIGHT...WILL PROLONG SW FLOW ALOFT AND
DELAY ANY CLEARING. WITH PLENTY OF CLOUDS TONIGHT...PLAYED LOW
TEMPERATURES CLOSE TO THE ADJMET WITH READINGS FROM AROUND 60
DEGREES IN THE MOUNTAINS TO THE UPPER 60S TO NEAR 70 IN THE
SOUTHEAST.
THE COLD FRONT WILL MOVE SOUTH INTO NORTH CAROLINA FOR SATURDAY.
THERE IS ENOUGH MOISTURE TO COMBINED WITH WEAK UPPER LEVEL
DISTURBANCES AND SURFACE WIND CONVERGENCE TO PRODUCE SHOWERS AND A
FEW THUNDERSTORMS. HIGH TEMPERATURES ON SATURDAY WILL VARY THE MID
70S IN THE MOUNTAINS TO THE MID 80S IN THE SOUTHEAST.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 320 PM EDT FRIDAY...
COLD FRONT WILL BE DOWN IN THE CAROLINAS BY SAT NIGHT WITH DRIER AND
COOLER AIR SEEPING SOUTHBOUND ALLOWING FOR AN EXODUS OF MOST
LEFTOVER SHRA OVER THE SOUTH SAT EVENING. NEXT MID LEVEL IMPULSE
PROGGED BY MOST MODELS WILL ROUND THE 5H TROF SLIDING THRU THE UPPER
MIDWEST SUNDAY AND DAMPEN UPON PASSING INTO THE OHIO VALLEY SUNDAY
NIGHT. DEEPER MOISTURE WITH THE RESIDUAL FRONT LOOKS TO REMAIN JUST
SOUTH OF THE CWA THOUGH AS OVERALL MID LEVEL BACKING OF THE FLOW
AHEAD OF THE WAVE APPEARS WEAK ATTM. HOWEVER WITH LOW LEVEL
TRAJECTORIES TURNING MORE SOUTH/SE AND A RIBBON OF HIGHER SFC-85H
THETA-E SPREADING ALONG/EAST OF THE BLUE RIDGE...WENT AHEAD AND
EXPANDED THE CHANCE POPS NORTH SUNDAY/SUNDAY EVENING...WITH BEST
COVERAGE SOUTHERN HALF WHERE SOME CAPE WILL EXIST. SHRA MAY LINGER
EAST SUNDAY NIGHT AND BUBBLE BACK TO THE WEST ON MONDAY AS YET
ANOTHER UPPER LEVEL DISTURBANCE SPINS BY AND PERHAPS INDUCES A SFC
WAVE ALONG THE FRONT TO THE SOUTH MONDAY AFTERNOON PER THE LATEST
CANADIAN. AGAIN MAINLY MIDDLE RANGE CHANCE POPS FOR NOW GIVEN
UNCERTAINTY AND ONLY SLIGHT POPS FAR WEST/NW WHERE REMOVED FROM THE
DEEPER RH. OTRW MORE CLOUDS SOUTH/EAST AND PERHAPS MORE
BREAKS/CLEARING AT TIMES NORTH-NW THRU MONDAY. CLOUDS/SHRA SHOULD
KEEP HIGHS MAINLY IN THE 70S TO LOW 80S WITH LOWS 50S TO LOW 60S
MOUNTAINS...AND 60-65 BEHIND THE FRONT OUT EAST.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 1215 PM EDT FRIDAY...
UPPER TROF ACROSS THE EAST WILL GRADUALLY WEAKEN AND START TO LIFT
OUT BY LATE IN THE WEEK AS WEAK SURFACE HIGH PRESSURE REMAINS IN
PLACE. HOWEVER MODELS SUGGEST THAT A 5H IMPULSE ROTATING AROUND THE
DEPARTING TROFFINESS THRU THE MID MISS VALLEY...COULD EVOLVE INTO A
WEAK UPPER LOW BY MID WEEK WHICH MAY SLIP EAST INTO THE CENTRAL
APPALACHIANS BY FRIDAY. THIS QUITE UNCERTAIN AND MAINLY SUPPORTED BY
THE LATEST ECMWF...BUT WOULD BE ENOUGH TO LIKELY ENHANCE CONVECTIVE
CHANCES LATER IN THE WEEK DESPITE WEAK RIDGING IN PLACE. OTRW TREND
IN THE OVERALL FORECAST REMAINS ON THE DRY SIDE WITH THE RESIDUAL
AXIS OF DEEPER MOISTURE STILL TO THE SE...AND CONTINUED DRIER NORTH
TO NE FLOW IN PLACE. THIS LOW LEVEL ONSHORE FLOW COULD BRING IN SOME
LOW CLOUDS TO ALONG THE BLUE RIDGE AT TIMES DURING THE OVERNIGHTS
BUT IFFY. OTRW INTERVALS OF CLOUDS AND SUN THRU THE PERIOD WITH
MAINLY DIURNALLY DRIVEN SLIGHT CHANCE CONVECTIVE POPS ESPCLY SW AND
MOUNTAINS WHERE AIDED BY LOCAL CONVERGENCE. COVERAGE PERHAPS A BIT
MORE LATE IN THE WEEK OVER THE SOUTH IF THE WEAK CUTOFF DEVELOPS AND
BETTER MOISTURE GETS RETURNED NORTH. TEMPS MAINLY PERSISTENCE THRU
THE PERIOD UNDER HIGH PRESSURE/LIGHT WINDS...AND ONLY SLIGHT WARMING
ALOFT...WITH HIGHS 70S TO ARND 80 MOUNTAINS AND LOW/MID 80S EAST.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 150 AM EDT SATURDAY...
MOSTLY VFR CONDITIONS EXPECTED THIS TAF VALID PERIOD. SPOTTY -RA
NOTED ACROSS SW VA TOWARD BCB/ROA...WILL LIKELY DISSIPATE BY 08Z.
THIS IS ASSOCIATED WITH THE DISSIPATING FRONTAL BOUNDARY AS IT LOSES
UPPER SUPPORT TO CONTINUE MUCH FURTHER EAST PROGRESS. TYPICAL
UPSLOPE FLOW NOTED ON THE WV SIDE RESULTING IN IFR CIGS/VSBYS AGAIN
AT BLF...WITH FOG DEVELOPING AT LWB. EXPECT IFR CIGS/VSBYS AT
LWB/BLF OVERNIGHT...OTHERWISE VFR AFT 13Z THERE AS WELL. EXTENSIVE
MID CLOUDS WILL LINGER ACROSS THE EASTERN 2/3RD OF THE CWA TODAY AND
IMPACT MOST TAF SITES WITH BKN-OVC CIGS...YET AOA080 IN ALL CASES
AFT 13Z. WINDS WILL VEER TO THE NE THROUGH THE DAY...ESPECIALLY EAST
OF THE BLUE RIDGE...WITH VRB03KT PREVAILING WEST OF THE BLUE RIDGE
THROUGH MOST OF THE TAF VALID PERIOD.
AS OF 830 PM EDT FRIDAY...
SHOWERS AND THUNDERSTORMS HAVE MAINLY EXITED THE REGION AS OF 00Z.
THE EXCEPTION IS SOME VERY LIGHT RAIN SHOWERS MOVING ACROSS WESTERN
VIRGINIA AS A WEAK DISTURBANCE PASSES BY. LEFT A CHANCE OF RAIN AT
BLF THROUGH 02Z. THE HRRR FORECAST MODEL SHOWS ANY SHOWERS THAT
DEVELOP ALONG THE COLD FRONT WILL DISSIPATE EAST OF THE BLUE RIDGE
TONIGHT THANKS TO THE NORTHWESTERLY DOWNSLOPE FLOW.
WESTERLY FLOW WILL PROMOTE LOW CEILINGS AT LWB AND BLF...AND
POSSIBLY FOR A SHORT TIME AT BCB...IFR CONDITIONS ARE EXPECTED
DURING THE EARLY MORNING HOURS ON SATURDAY. A DOWNSLOPE FLOW FURTHER
EAST TONIGHT SHOULD KEEP CEILINGS AT ROA/LYH/DAN FROM DROPPING BELOW
3KFT DURING THE EARLY MORNING HOURS...ALTHOUGH LIGHT RAIN EARLIER
THIS EVENING MAY CAUSE LIGHT FOG TO DEVELOP BEFORE SUNRISE. BY 15Z
SATURDAY ALL TAF LOCATIONS WILL RETURN TO VFR CONDITIONS AS DAYTIME
HEATING INCREASES...ERODING THE REMAINING LOW CLOUDS.
A DEVELOPING LOW PRESSURE SYSTEM ACROSS EASTERN CANADA WILL KEEP OUR
REGION UNSETTLED THROUGH THE EARLY PART OF NEXT WEEK. VFR CONDITIONS
ARE EXPECTED FOR THE MAJORITY OF THE PERIOD...WITH ISOLATED IFR/MVFR
CONDITIONS POSSIBLE WHERE SHOWERS AND THUNDERSTORMS DEVELOP.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...DS/KK/RAB
NEAR TERM...RAB/DS/KK
SHORT TERM...JH
LONG TERM...JH
AVIATION...RAB/CF/KK/NF
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
645 PM CDT SUN AUG 19 2012
.SHORT TERM...THROUGH TUESDAY NIGHT
246 PM CDT SUN AUG 19 2012
SURFACE ANALYSIS THIS AFTERNOON SHOWS A WEAK COLD FRONT EXTENDING
ACROSS CENTRAL WISCONSIN INTO WESTERN MINNESOTA. HIGH PRESSURE WAS
CENTERED OVER NORTHERN NORTH DAKOTA.
LOCAL AND REGIONAL RADARS ARE SHOWING A FEW SHOWERS DEVELOPING
ALONG AND AHEAD OF THE FRONT ACROSS WISCONSIN INTO EASTERN
MINNESOTA. MU CAPES AROUND A 1000 J/KG ARE IN PLACE AHEAD OF THE
FRONT BUT WITH A WEAK WIND FIELD...THE CONVERGENCE ALONG THE FRONT
IS NOT VERY STRONG. A WEAK SHORT WAVE TROUGH WAS PROVIDING ENOUGH
LIFT TO AID THE DEVELOPMENT OF THE SHOWERS. THIS WAVE WILL SLIP
SOUTH OF THE AREA THIS EVENING TAKING THE FORCING WITH IT. SOME
CONCERN THAT ADDITIONAL WAVES UP STREAM IN THE FLOW ALOFT COULD
CONTINUE TO PROVIDE SOME WEAK FORCING THROUGH THE NIGHT.
HOWEVER...ONCE THE FRONT GOES THROUGH DEW POINTS ARE EXPECTED TO
FALL INTO THE 40S. THIS ALONG WITH THE LOSS OF HEATING...SHOULD BE
SUFFICIENT TO LOWER CAPE AND ALLOW THE SHOWERS TO DISSIPATE. WILL
CARRY A SMALL RAIN CHANCE ACROSS THE SOUTHERN HALF OF THE AREA INTO
THE EVENING TO COVER THE DISSIPATING EVENING SHOWERS.
ONCE THE SHOWERS ARE DONE...THE SKIES SHOULD CLEAR OUT AND WITH
THE HIGH BUILDING IN...THE CONCERN BECOMES WHETHER VALLEY FOG WILL
FORM. ONCE AGAIN...THIS DOES NOT LOOK TO BE A CLEAR CUT EVENT. THE
WINDS AT THE SURFACE ARE EXPECTED TO DECOUPLE AND WITH THE CLEAR
SKIES...GOOD RADIATIONAL COOLING SHOULD OCCUR. HOWEVER...THE
FORECAST SOUNDINGS FROM BOTH THE 19.12Z NAM AND 19.17Z RAP SUGGEST
THE WINDS JUST ABOVE THE SURFACE UP THROUGH AT LEAST 5K FEET
SHOULD BE AROUND 10 KNOTS...BUT DECREASING TOWARD 12Z MONDAY.
ALSO...THE NAM SUGGESTS THAT SATURATION SHOULD ONLY OCCUR AT THE
SURFACE WITH DRIER AIR ABOVE WITH THE STRONGER WINDS. WOULD EXPECT
SOME FOG TO BE AROUND BUT WOULD NOT EXPECT THE WHOLE VALLEY TO
FILL IN AND WILL MAINTAIN THE MENTION OF AREAS OF VALLEY FOG. THE
HIGH WILL THEN DRIFT SOUTHEAST ACROSS THE AREA AND PROVIDE QUIET
WEATHER INTO TUESDAY NIGHT.
.LONG TERM...WEDNESDAY THROUGH SUNDAY
246 PM CDT SUN AUG 19 2012
MODELS IN THIS TIME FRAME HAVE BEEN SHOWING SOME INCONSISTENCIES
ON HOW THE PATTERN WILL EVOLVE AS ENERGY COMES OUT OF THE MEAN
LONG WAVE TROUGH ALONG THE WEST COAST. THE LATEST MODELS RUNS
STILL SHOW A SHORT WAVE TROUGH COMING OUT OF THE WEST COAST SYSTEM
STARTING WEDNESDAY. HOWEVER...NOW INSTEAD OF BUILDING INTO THE
UPPER MIDWEST...THE UPPER LEVEL LOW MOVES NORTHEAST TOWARD CENTRAL
CANADA BRINGING THE SHORT WAVE TROUGH THROUGH THE AREA WITH A
POSITIVE TILT THURSDAY NIGHT THROUGH FRIDAY NIGHT. AS THIS IS
HAPPENING...THE UPPER LEVEL THAT HAD BEEN OFF THE WEST COAST IS
SHOWN TO START MOVING EAST ACROSS SOUTHERN CANADA IMPACTING THE
UPPER MIDWEST OVER THE WEEKEND. AT THE SURFACE...THE 19.12Z GFS
REMAINS STRONGER WITH THE LEAD SYSTEM THAN THE 19.00Z ECMWF
SHOWING A LOW ALONG THE CANADIAN BORDER WITH A COLD FRONT COMING
INTO THE AREA. MEANWHILE...THE ECMWF CONTINUES TO JUST SHOW A WEAK
SURFACE LOW DRIFTING ACROSS THE UPPER MIDWEST. BOTH MODELS THEN
SHOW A LOW MOVING ACROSS CANADA WITH ANOTHER COLD FRONT OVER THE
UPPER MIDWEST WITH THE MAIN UPPER LEVEL LOW...BUT DIFFER ON THE
TIMING WITH THE GFS BEING THE QUICKEST. IN GENERAL...WILL CARRY 30
TO 40 PERCENT RAIN CHANCES STARTING THURSDAY NIGHT THROUGH THE
WEEKEND AND WAIT FOR LATER MODEL RUNS AND HOPEFULLY BETTER
AGREEMENT TO MAKE REFINEMENTS.
&&
.AVIATION...TONIGHT AND MONDAY
645 PM CDT SUN AUG 19 2012
THE FORECAST CONCERNS ARE FOCUSED ON RIVER VALLEY FOG POTENTIAL
OVERNIGHT AT LSE. THE FAVORABLE FOG CONDITIONS ARE CLEAR SKIES
ASSOCIATED WITH A BUILDING HIGH PRESSURE...RECENT RAIN SHOWERS IN
THE VICINITY OF KLSE...CROSSOVER TEMPERATURES IN THE LOW 50S
/WHICH SHOULD BE SATISFIED FOR A FEW HOURS/...AND MARGINAL 03Z
T/TD SPREADS. THE NEGATIVES FOR FOG DEVELOPMENT ARE BOUNDARY LAYER
WINDS THROUGH 1 KM...WHICH OFF THE NAM AND RAP SOUNDINGS APPROACH
10-15 KTS. HOWEVER...BY 10-11Z THE WINDS DO RELAX A BIT BELOW 10
KTS. ALSO A CONCERN IS THE RATHER DRY AIRMASS BEING ADVECTED IN
FROM NORTHERN WISCONSIN WHERE DEWPOINTS LATE THIS AFTERNOON WERE
IN THE 30S. THINKING THAT THOSE SPOTS MIXED OUT MUCH MORE
TODAY...AND THERE SHOULD BE ENOUGH DEWPOINT RECOVERY TO APPROACH
SATURATION. GIVEN ALL OF THE ABOVE FACTORS...CONFIDENCE IS HIGH
ENOUGH TO INTRODUCE IFR CONDITIONS BEGINNING AT 11Z. FOG WILL MIX
OUT BETWEEN 13-14Z.
OTHERWISE...FOR MONDAY SURFACE HIGH PRESSURE WILL BE THE RULE
PROVIDING LIGHT NORTHWEST WINDS. BY LATE MORNING...A SCATTERED 5
KFT CUMULUS FIELD SHOULD DEVELOP ACROSS THE REGION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
246 PM CDT SUN AUG 19 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...ZT
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1128 PM MDT FRI AUG 17 2012
.AVIATION...06Z TAF ISSUANCE...
WINDS WILL SHIFT TO NORTHERLY BEHIND A COLD FRONT WHICH WILL MOVE
ACROSS THE AREA TONIGHT. HIGH PRESSURE AXIS TO MOVE ACROSS THE
AREA LATE TONIGHT AND EARLY SATURDAY. SOME BREEZY CONDITIONS
SATURDAY AFTERNOON WITH WINDS GUSTS 15 TO 25 MPH BUT THEN WINDS
TO AGAIN BECOME LIGHT SATURDAY NIGHT. A FEW STRAY SHOWERS POSSIBLE
LATE THIS EVENING OVER SOUTHEAST WY...OTHERWISE DRY WITH VFR
THROUGH SATURDAY NIGHT.
&&
.PREV DISCUSSION... /ISSUED 705 PM MDT FRI AUG 17 2012/
DISCUSSION...
SURFACE COLD FRONT APPEARED TO BE ROUGHLY FROM EAST OF KCDR TO
NEAR KEAN AT 00Z. HOWEVER...WINDS FURTHER SOUTH HAVE TURNED TO
MORE NORTHEAST AS WELL IN MUCH OF SOUTHEAST WYOMING. THE FRONT
SHOULD MOVE THROUGH THE ENTIRE CWA BY 09Z. ATMOSPHERE IS DRY
AND RELATIVELY STABLE EARLY THIS AFTERNOON OVER THE CWA. SOME
WEAK RETURNS WERE OBSERVED AROUND 2330Z ON THE COLORADO BORDER
SOUTH OF LARAMIE. ADDITIONAL DEVELOPMENT SEEMS UNLIKELY THE REST
OF TONIGHT...SO HAVE TAKEN OUT THE MENTION OF SHOWERS AND STORMS
IN A RECENT UPDATE. OTHERWISE...ONLY MINOR FIRST PERIOD CHANGES
WERE MADE TO THE FORECAST.
PREV DISCUSSION... /ISSUED 249 PM MDT FRI AUG 17 2012/
.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT...
WATER VAPOR IMAGERY SHOWS FAST NORTHWEST FLOW ALOFT OVER THE WY/MT
WITH A STRONG SHORTWAVE DIVING SOUTHWARD OVER SASKATCHEWAN. CUMULUS
HAVE DEVELOPED OVER THE LARAMIE RANGE BUT FAILED TO MOVE EASTWARD
OVER THE PLAINS. THE MODELS ARE IN AGREEMENT IN SHOWING THE
SHORTWAVE DIVING SSE OVER THE NORTHERN PLAINS THROUGH TONIGHT.
ALTHOUGH THERE IS LIMITED LOW AND MID LEVEL MOISTURE TO WORK
WITH...THE QG LIFT AHEAD OF THE SHORTWAVE COULD ENHANCE CONVECTIVE
CHANCES LATE THIS AFTERNOON AND EVENING. CURRENT LAPS ANALYSIS SHOWS
WEAK SFC INSTABILITY OVER THE PLAINS (WITH A FEW HUNDRED J/KG OF
CAPE). BOTH THE GFS AND HRRR MODELS GENERATE ISOLATED STORMS OVER
THE SOUTHEASTERN PART OF THE CWA BETWEEN 00Z AND 06Z. KEPT SLIGHT
CHANCE POPS FOR MAINLY AREAS ALONG INTERSTATE 80 TO THE EAST OF THE
LARAMIE RANGE THROUGH EARLY TONIGHT. A 1018MB SFC HIGH BEHIND THE
SHORTWAVE WILL DRIVE A COLD FRONT THROUGH THE AREA LATE TONIGHT.
BREEZY CONDITIONS WILL DEVELOP SAT MORNING AFTER THE FROPA...HOWEVER
PRESSURE RISES/SOUNDINGS DO NOT SUGGEST THAT THE WINDS WILL BE
PARTICULARLY STRONG.
RATHER QUIET THROUGH THE REMAINDER OF THE SHORT TERM WITH VERY DRY
NORTHWESTERLY FLOW ALOFT. HIGHS ON SAT WILL BE AROUND 5 DEGREES
COOLER IN THE POST FRONTAL AIRMASS. THE BREEZY NORTHERLY WINDS
WILL SUBSIDE ON SAT NIGHT AS THE SFC HIGH PRESSURE CENTER SETTLES
OVER THE CWA. WENT A FEW DEGREES COOLER THAN MOS FOR LOWS ON SAT
NIGHT...WITH VALUES MAINLY IN THE MID-TO-UPPER 40S OVER THE
PLAINS...WITH GOOD RADIATION AL COOLING POTENTIAL. 700MB TEMPS RISE
ON SUN TO 9C (FROM 7C ON SAT) FOR A FEW DEGREES OF WARMING...BUT
LITTLE OTHER CHANGE IN THE SENSIBLE WEATHER. A SHORTWAVE WILL
ROUND THE TOP OF THE INTERMOUNTAIN WEST RIDGE ON SUN
NIGHT...APPROACHING THE CWA BY MON.
.LONG TERM...MONDAY THROUGH FRIDAY...
LONG TERM GENERALLY DOMINATED BY A RIDGE OF HIGH PRESSURE WITH THE
RIDGE AXIS WEST OF THE CWA EARLY. WE GET A SHORTWAVE THAT MOVES DOWN
THROUGH THE NORTHWEST FLOW MONDAY...EXITING EAST BY MONDAY
AFTERNOON. GENERALLY DRY CONDITIONS EXPECTED WITH THE EXCEPTION
POSSIBLY BEING THE HIGHER TERRAIN OF THE SNOWY...SIERRA MADRE AND
NORTHERN LARAMIE RANGES MONDAY AFTERNOON.
RIDGE AXIS THEN BUILDS OVER THE CWA TUESDAY WITH THE AXIS SHIFTING
EAST BY TUESDAY AFTERNOON. COULD SEE AN INCREASE IN FIRE WEATHER
CONCERNS AS WINDS SHIFT SOUTHWEST AND BEGIN TO INCREASE. GFS
SHOWING 20 TO 25KT OF WIND AT 700MB AS ANOTHER SHORTWAVE TRACKS
INTO IDAHO AND NORTHERN UTAH. THIS SHORTWAVE TRACKS NORTHEAST
ACROSS WESTERN WYOMING TUESDAY NIGHT INTO WEDNESDAY...DRAGGING A
COLD FRONT THROUGH AT LEAST OUR WESTERN ZONES WEDNESDAY EVENING.
MAINTAINED...AND SLIGHTLY INCREASED POP COVERAGE FOR THIS AREA
WEDNESDAY NIGHT. WEDNESDAY MOST LIKELY OUR WARMEST DAY NEXT WEEK
WITH HIGHS CLIMBING BACK INTO THE 90S WITH THESE GUSTY WINDS. DRIER
CONDITIONS RETURNING FOR THE END OF THE WEEK CWA WIDE.
&&
.FIRE WEATHER...
FIRE WEATHER CONCERNS WILL BE MINIMAL THROUGH THE WEEKEND. A COLD
FRONT WILL MOVE ACROSS THE AREA TONIGHT BRINGING BREEZY NORTHERLY
WINDS AND COOLER THAN AVERAGE TEMPERATURES ON SATURDAY. MINIMUM
AFTERNOON RELATIVE HUMIDITY VALUES WILL BE IN THE 15 TO 20 PERCENT
RANGE. THE AIRMASS WILL BEGIN TO WARM ON SUNDAY WITH AFTERNOON
HUMIDITIES DROPPING BELOW 15 PERCENT TO THE WEST OF THE LARAMIE
RANGE. HOWEVER...WINDS WILL BE LIGHT WITH THE SURFACE HIGH PRESSURE
CENTER NEAR SOUTHEAST WYOMING. PRECIPITATION CHANCES WILL BE LOW
THROUGH EARLY NEXT WEEK WITH A DRY AIRMASS IN PLACE...HOWEVER SOME
ISOLATED SHOWER AND THUNDERSTORMS WILL BE POSSIBLE STARTING MONDAY
OVER THE MOUNTAINS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...RE
LONG TERM/AVIATION...MAJ
PREVIOUS DISCUSSIONS...MSW/SML/GCC/ZAF
AREA FORECAST DISCUSSION
NWS NEW YORK NY
447 AM EDT MON AUG 20 2012
.SYNOPSIS...
A BROAD AREA OF HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH
TUESDAY. A WEAK COASTAL LOW MAY AFFECT THE AREA WEDNESDAY INTO
WED NIGHT. OTHERWISE...WEAK HIGH PRESSURE WILL BE THE RULE ACROSS
THE EAST COAST FROM MID WEEK INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL NOON TODAY/...
LOW PRES AT 7Z WAS ABOUT 50 MILES E OF NORFOLK VA. MODELS HAVE
CONVERGED ON A SOLN TAKING THE SYSTEM E OF THE BENCHMARK BY 00Z.
WITH THIS TRACK...ONLY A FEW LIGHT SHRA OR SPRINKLES COULD CLIP
LI THIS MRNG. SLIGHT CHANCES INCLUDED FOR THIS. TO THE
W...STRENGTHENING H3 JET PROGGED TO DEVELOP SHRA. TIMING FOR
DEVELOPMENT HOWEVER LOOKS TO BE AFT 15Z WHEN THE REQUISITE
INSTABILITY BUILDS.
&&
.SHORT TERM /NOON TODAY THROUGH 6 PM TUESDAY/...
HIGH PRES RIDGE RIGHT OVER THE CWA TODAY WITH VERY LIGHT SFC
FLOW. BEST CHANCE FOR PCPN DEVELOPMENT WILL BE WRN ZONES INVOF
THE UPR DYNAMICS. CAPE IS WEAK...BUT THERE SHOULD BE SUFFICIENT
LIFT DUE TO THE APPROACHING 120KT H3 JET. CANNOT RULE OUT ISOLD
THUNDER OR EVEN SMALL HAIL DUE TO THE DEEP SYNOPTIC LIFT. TEMPS A
BLEND OF THE MET/MAV WHICH HAVE CONVERGED ON HIGHS GENERALLY NEAR
80.
THE REMNANTS OF ANY DAYTIME ACTIVITY RESULT IN A FEW SPOTTY SHRA
OVERNIGHT. ISOLD/SLIGHT CHANCE POPS TO ACCOUNT FOR THIS.
THE HIGH PRES RIDGE IS DISPLACED OFFSHORE FOR TUE WITH WEAK RETURN
FLOW OVER THE CWA. A LITTLE MORE INSTABILITY SO INCLUDED TSTMS IN
THE FCST. COVERAGE LOOKS TO BE ISOLD ATTM. THE GFS HAS A STRONGER
H3 JET STRUCTURE THAN THE NAM FOR THIS PERIOD...WITH THE AREA IN
THE RR QUAD. HIGH TEMPS INCREASE A FEW DEGREES DUE TO DEEPER
MIXING.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MEAN EAST COAST TROUGHING LOOKS TO BE THE RULE THROUGH THE WORK
WEEK...WITH NUMEROUS WEAK SHORTWAVE TROUGHS PIVOTING THROUGH THE NE.
AT THE SURFACE...A STALLED BOUNDARY REMAINS OFFSHORE WITH NUMEROUS
LOW PRESSURE WAVES TRACKING ALONG IT...WHILE WEAK HIGH PRESSURE
REMAINS OVER THE EAST COAST INTERRUPTED BY DAILY THERMAL TROUGHING
ALONG THE COASTAL PLAIN.
STILL SOME UNCERTAINTY FOR WED/WED NIGHT PERIOD WITH MODELS
INCONSISTENTLY SIGNALING A STRONGER LOW PRESSURE WAVE TRACKING NE
ALONG A STALLED FRONTAL BOUNDARY. 00Z OPERATIONAL SOLUTIONS/00Z GEFS
ARE UNANIMOUSLY KEEPING THE LOW WEAKER AND FURTHER OFFSHORE FOR
WED/WED NIGHT. BUT BASED ON MODEL PERFORMANCE IN THIS
PATTERN...CONFIDENCE NOT HIGH ON THIS SUITE OF SOLUTIONS. CAN`T RULE
OUT A TREND BACK TOWARDS A STRONGER/CLOSER SOLUTION OVER THE NEXT
DAYS OR SO...PARTICULARLY AHEAD OF AN APPROACHING SHORTWAVE TROUGH
AXIS AND IN FAVORABLE RIGHT REAR JET PLACEMENT. SO WILL CONTINUE
WITH SLIGHT CHANCE POPS FOR EITHER A LOW PROBABILITY OF SHOWER
ACTIVITY FROM A COASTAL WAVE...OR FROM ISOLATED DIURNAL CONVECTIVE
DEVELOPMENT ACROSS THE INTERIOR WITH MARGINAL INSTABILITY AND
SHORTWAVE TROUGH APPROACH.
OTHERWISE...OVERALL APPEARS TO BE AN UNEVENTFUL PATTERN THROUGH THE
PERIOD...WITH ONLY ISOLATED POTENTIAL FOR SHRA/TSRA ACROSS INTERIOR
DUE TO WEAK DIURNAL INSTABILITY. NEAR NORMAL TEMPS WITH HIGHER IN
THE LOWER 80S AND LOWS IN THE 60S...SLIGHT WARMER NE NJ/NYC METRO.
THERE ARE SIGNS THAT MEAN TROUGHING MAY BREAK DOWN FOR THE
WEEKEND...WHICH WOULD RESULT IN CONTINUED TRANQUIL WEATHER WITH
WARMING TO SLIGHTLY ABOVE NORMAL TEMPS.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
WEAK LOW PRESSURE PASSES WELL TO OUR SOUTH INTO THIS EVENING...A
WEAK TROUGH OF LOW PRESSURE BUILDS IN TONIGHT.
VFR THROUGH THE TAF PERIOD. LOOKING INCREASINGLY LIKE MOST IF NOT
ALL THE AREA WILL STAY DRY. BEST CHANCE OF ANY PRECIPITATION IS OVER
FAR WESTERN TERMINALS THIS AFTERNOON/EARLY THIS EVENING WHERE THERE
COULD BE A PASSING SHOWER. HAVE A PROB30 IN AT KSWF FOR NOW. AT
REMAINDER OF TERMINALS CHANCE OF PRECIPITATION IS 20 PERCENT OR LESS.
MAINLY LIGHT AND VARIABLE WINDS THROUGH THE TAF PERIOD. COASTAL
TERMINALS COULD SEE A BRIEF PERIOD OF SEA BREEZE INFLUENCE THIS
AFTERNOON. CONFIDENCE IN ANY WIND DIRECTION FORECAST IS LOW.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP://WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED THROUGH
AT LEAST MID MORNING.
KLGA FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED THROUGH
AT LEAST MID MORNING.
KEWR FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED THROUGH
AT LEAST MID MORNING.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED THROUGH
AT LEAST MID MORNING.
KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED THROUGH
AT LEAST MID MORNING.
KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED THROUGH
AT LEAST MID MORNING.
OUTLOOK FOR 06Z TUESDAY THROUGH FRIDAY...
.LATE MONDAY NIGHT-FRIDAY...MOST LIKELY VFR. SMALL CHANCE MVFR OR
LOWER TUESDAY-WEDNESDAY DEPENDING ON EXACT TRACK OF A LOW
FORECAST TO PASS TO THE SE OF LONG ISLAND.
&&
.MARINE...
WINDS AND SEAS WILL REMAIN BLW SCA LVLS THRU TUE WITH HIGH PRES
OVER THE WATERS.
MAINLY TRANQUIL SUB-SCA CONDITIONS EXPECTED FROM MIDWEEK INTO THE
COMING WEEKEND WITH A WEAK PRESSURE GRADIENT REMAINING OVER THE
REGION.
THERE IS STILL UNCERTAINTY WITH THE EVOLUTION OF A WAVE OF A COASTAL
LOW PRESSURE ON WED/WED NIGHT. THERE IS ONLY A SLIGHT CHANCE THAT
THIS SETUP COULD PRODUCE MARGINAL SCA CONDS ON THE OCEAN. EXPECTED
SCENARIO IS A WEAK AND WELL OFFSHORE WAVE...WITH SUB SCA CONDS.
&&
.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH THIS WEEKEND.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JMC/NV
NEAR TERM...JMC
SHORT TERM...JMC
LONG TERM...NV
AVIATION...MALOIT
MARINE...JMC/NV
HYDROLOGY...JMC
AREA FORECAST DISCUSSION
NWS NEW YORK NY
351 AM EDT MON AUG 20 2012
.SYNOPSIS...
A BROAD AREA OF HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH
TUESDAY. A WEAK COASTAL LOW MAY AFFECT THE AREA WEDNESDAY INTO
WED NIGHT. OTHERWISE...WEAK HIGH PRESSURE WILL BE THE RULE ACROSS
THE EAST COAST FROM MID WEEK INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL NOON TODAY/...
LOW PRES AT 7Z WAS ABOUT 50 MILES E OF NORFOLK VA. MODELS HAVE
CONVERGED ON A SOLN TAKING THE SYSTEM E OF THE BENCHMARK BY 00Z.
WITH THIS TRACK...ONLY A FEW LIGHT SHRA OR SPRINKLES COULD CLIP
LI THIS MRNG. SLIGHT CHANCES INCLUDED FOR THIS. TO THE
W...STRENGTHENING H3 JET PROGGED TO DEVELOP SHRA. TIMING FOR
DEVELOPMENT HOWEVER LOOKS TO BE AFT 15Z WHEN THE REQUISITE
INSTABILITY BUILDS.
&&
.SHORT TERM /NOON TODAY THROUGH 6 PM TUESDAY/...
HIGH PRES RIDGE RIGHT OVER THE CWA TODAY WITH VERY LIGHT SFC
FLOW. BEST CHANCE FOR PCPN DEVELOPMENT WILL BE WRN ZONES INVOF
THE UPR DYNAMICS. CAPE IS WEAK...BUT THERE SHOULD BE SUFFICIENT
LIFT DUE TO THE APPROACHING 120KT H3 JET. CANNOT RULE OUT ISOLD
THUNDER OR EVEN SMALL HAIL DUE TO THE DEEP SYNOPTIC LIFT. TEMPS A
BLEND OF THE MET/MAV WHICH HAVE CONVERGED ON HIGHS GENERALLY NEAR
80.
THE REMNANTS OF ANY DAYTIME ACTIVITY RESULT IN A FEW SPOTTY SHRA
OVERNIGHT. ISOLD/SLIGHT CHANCE POPS TO ACCOUNT FOR THIS.
THE HIGH PRES RIDGE IS DISPLACED OFFSHORE FOR TUE WITH WEAK RETURN
FLOW OVER THE CWA. A LITTLE MORE INSTABILITY SO INCLUDED TSTMS IN
THE FCST. COVERAGE LOOKS TO BE ISOLD ATTM. THE GFS HAS A STRONGER
H3 JET STRUCTURE THAN THE NAM FOR THIS PERIOD...WITH THE AREA IN
THE RR QUAD. HIGH TEMPS INCREASE A FEW DEGREES DUE TO DEEPER
MIXING.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MEAN EAST COAST TROUGHING LOOKS TO BE THE RULE THROUGH THE WORK
WEEK...WITH NUMEROUS WEAK SHORTWAVE TROUGHS PIVOTING THROUGH THE NE.
AT THE SURFACE...A STALLED BOUNDARY REMAINS OFFSHORE WITH NUMEROUS
LOW PRESSURE WAVES TRACKING ALONG IT...WHILE WEAK HIGH PRESSURE
REMAINS OVER THE EAST COAST INTERRUPTED BY DAILY THERMAL TROUGHING
ALONG THE COASTAL PLAIN.
STILL SOME UNCERTAINTY FOR WED/WED NIGHT PERIOD WITH MODELS
INCONSISTENTLY SIGNALING A STRONGER LOW PRESSURE WAVE TRACKING NE
ALONG A STALLED FRONTAL BOUNDARY. 00Z OPERATIONAL SOLUTIONS/00Z GEFS
ARE UNANIMOUSLY KEEPING THE LOW WEAKER AND FURTHER OFFSHORE FOR
WED/WED NIGHT. BUT BASED ON MODEL PERFORMANCE IN THIS
PATTERN...CONFIDENCE NOT HIGH ON THIS SUITE OF SOLUTIONS. CAN`T RULE
OUT A TREND BACK TOWARDS A STRONGER/CLOSER SOLUTION OVER THE NEXT
DAYS OR SO...PARTICULARLY AHEAD OF AN APPROACHING SHORTWAVE TROUGH
AXIS AND IN FAVORABLE RIGHT REAR JET PLACEMENT. SO WILL CONTINUE
WITH SLIGHT CHANCE POPS FOR EITHER A LOW PROBABILITY OF SHOWER
ACTIVITY FROM A COASTAL WAVE...OR FROM ISOLATED DIURNAL CONVECTIVE
DEVELOPMENT ACROSS THE INTERIOR WITH MARGINAL INSTABILITY AND
SHORTWAVE TROUGH APPROACH.
OTHERWISE...OVERALL APPEARS TO BE AN UNEVENTFUL PATTERN THROUGH THE
PERIOD...WITH ONLY ISOLATED POTENTIAL FOR SHRA/TSRA ACROSS INTERIOR
DUE TO WEAK DIURNAL INSTABILITY. NEAR NORMAL TEMPS WITH HIGHER IN
THE LOWER 80S AND LOWS IN THE 60S...SLIGHT WARMER NE NJ/NYC METRO.
THERE ARE SIGNS THAT MEAN TROUGHING MAY BREAK DOWN FOR THE
WEEKEND...WHICH WOULD RESULT IN CONTINUED TRANQUIL WEATHER WITH
WARMING TO SLIGHTLY ABOVE NORMAL TEMPS.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
WEAK LOW PRESSURE PASSES WELL TO OUR SOUTH INTO THIS EVENING...A
WEAK TROUGH OF LOW PRESSURE BUILDS IN TONIGHT.
VFR THROUGH THE TAF PERIOD. LOOKING INCREASINGLY LIKE MOST IF NOT
ALL THE AREA WILL STAY DRY. BEST CHANCE OF ANY PRECIPITATION IS OVER
FAR WESTERN TERMINALS THIS AFTERNOON/EARLY THIS EVENING WHERE THERE
COULD BE A PASSING SHOWER. HAVE A PROB30 IN AT KSWF FOR NOW. AT
REMAINDER OF TERMINALS CHANCE OF PRECIPITATION IS 20 PERCENT OR LESS.
MAINLY LIGHT AND VARIABLE WINDS THROUGH THE TAF PERIOD. COASTAL
TERMINALS COULD SEE A BRIEF PERIOD OF SEA BREEZE INFLUENCE THIS
AFTERNOON. CONFIDENCE IN ANY WIND DIRECTION FORECAST IS LOW.
OUTLOOK FOR 06Z TUESDAY THROUGH FRIDAY...
.LATE MONDAY NIGHT-FRIDAY...MOST LIKELY VFR. SMALL CHANCE MVFR OR
LOWER TUESDAY NIGHT-WEDNESDAY NIGHT DEPENDING ON EXACT TRACK OF A
LOW FORECAST TO PASS TO THE SE OF LONG ISLAND.
&&
.MARINE...
WINDS AND SEAS WILL REMAIN BLW SCA LVLS THRU TUE WITH HIGH PRES
OVER THE WATERS.
MAINLY TRANQUIL SUB-SCA CONDITIONS EXPECTED FROM MIDWEEK INTO THE
COMING WEEKEND WITH A WEAK PRESSURE GRADIENT REMAINING OVER THE
REGION.
THERE IS STILL UNCERTAINTY WITH THE EVOLUTION OF A WAVE OF A COASTAL
LOW PRESSURE ON WED/WED NIGHT. THERE IS ONLY A SLIGHT CHANCE THAT
THIS SETUP COULD PRODUCE MARGINAL SCA CONDS ON THE OCEAN. EXPECTED
SCENARIO IS A WEAK AND WELL OFFSHORE WAVE...WITH SUB SCA CONDS.
&&
.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH THIS WEEKEND.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JMC/NV
NEAR TERM...JMC
SHORT TERM...JMC
LONG TERM...NV
AVIATION...MALOIT
MARINE...JMC/NV
HYDROLOGY...JMC
AREA FORECAST DISCUSSION
NWS NEW YORK NY
138 AM EDT MON AUG 20 2012
.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN TONIGHT. A WEAK AREA OF LOW PRESSURE
MOVING NORTHEAST TOWARD THE MID ATLANTIC COAST LATE TONIGHT WILL
PASS SOUTHEAST OF THE AREA MONDAY INTO MONDAY NIGHT. HIGH
PRESSURE BUILDS BEHIND THE DEPARTING LOW...WITH ANOTHER WEAK
COASTAL LOW POSSIBLE WEDNESDAY INTO THURSDAY. HIGH PRESSURE
RETURNS FOR THE END OF THE WEEK INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
130 AM UPDATE...FCST ON TRACK WITH NO CHANGES MADE.
FORECAST ON TRACK WITH DRY WEATHER THIS EVENING. THE ONLY CHANGES
WERE MADE TO POP GRIDS FOR LATE TONIGHT TO SHOW SOME POTENTIAL FOR
ISOLATED SHOWERS. THIS IS IN RESPONSE TO SOME PVA ALOFT AT 500 MB
AS WELL AS INCREASING SOUTHWESTERLY JET AT AROUND 250MB PROMOTING
GREATER DIVERGENCE. THIS IS TURN WILL HELP A LOW DEVELOP OFF THE
MID-ATLANTIC COAST. LAST 3 RUNS OF THE HRRR FORECAST REFLECTIVITY HAVE
SHOWN DEVELOPMENT OF SHOWERS STARTING BETWEEN 7-10Z MONDAY AND NEW
SREF ALSO SHOWS A LOW CHANCE NEAR THIS TIMEFRAME.
HIGH PRESSURE OVER THE REGION WILL WEAKEN TONIGHT. THIS WILL ALLOW
AN AREA OF LOW PRESSURE TO MOVE OFF THE MID-ATLANTIC COAST BY MONDAY
MORNING. CLOUDS THICKEN AND LOWER OVERNIGHT AND MUCH OF THE
OVERNIGHT PERIOD WILL REMAIN DRY...HOWEVER SOME LIGHT SHOWERS ARE
EXPECTED TO DEVELOP TOWARDS DAYBREAK. OVERNIGHT LOWS TONIGHT ARE
EXPECTED TO FALL INTO 50S AND 60S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
LOW PRESSURE WILL PASS SOUTHEAST OF THE REGION THROUGH THE SHORT
TERM. MODELS STILL STRUGGLING WITH HOW MUCH PRECIPITATION THE CWA
WILL RECEIVE WITH THIS SYSTEM. 12Z NAM HAS THE REGION RECEIVING
BETWEEN 0.1 TO 0.30 OF PRECIP...WITH THE HIGHER AMOUNTS ACROSS THE
NYC METRO AND LONG ISLAND AND LESSER AMOUNTS NORTH AND WEST. THE 12Z
GFS KEEPS THE REGION DRY COMPLETELY. THEREFORE...HAVE LOWER POPS A
BIT AND WILL CARRY SCATTERED SHOWERS THROUGH THE DAY MONDAY. BY
MONDAY NIGHT...AS THE LOW MOVES EAST POPS WILL GRADUALLY LOWER AND
TAPER OFF BY MIDNIGHT. EXPECT MOSTLY CLOUDY TO CLOUDY SKIES FOR MUCH
OF THE PERIOD. THIS WILL KEEP TEMPERATURES COOL. CONTINUES WITH THE
FORECAST TREND OF FOLLOWING THE MET GUIDANCE AS HIGHS WILL ONLY
REACH THE LOWER AND MIDDLE 70S. MAV GUIDANCE WAS A GOOD 6-9 DEGREES
WARMER SEEMED UNREALISTIC WITH CLOUD COVER AND RAIN WAS NOT USED.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
WHILE THE MODELS ARE COMING INTO BETTER AGREEMENT FOR THE LONG
TERM...THERE ARE SOME MINOR DISCREPANCIES THAT LEAD TO SOME
UNCERTAINTY...ESPECIALLY MID WEEK. SURFACE HIGH PRESSURE BEGINS TO
BUILD IN TUESDAY AS THE SURFACE LOW DEPARTS TO THE NORTHEAST. A WEAK
TROUGH JUST TO THE NORTH...COMBINED WITH A WEAK SHORTWAVE MOVING
THROUGH ALONG THE EASTERN SIDE OF THE DEEPENING UPPER LEVEL TROUGH
COULD PRODUCE JUST ENOUGH LIFT TO GENERATE SOME AFTERNOON SHOWERS.
INSTABILITY REMAINS ON THE LOWER END...SO NOT EXPECTING MUCH IN THE
FORMATION OF THUNDERSTORMS...THOUGH AN ISO TSTORM CAN NOT BE RULED
OUT. THE HIGH BEGINS TO TAKE MORE CONTROL OF THE REGION BY TUES
NIGHT...SO HAVE DIMINISHED POPS FOR OVERNIGHT.
NOW...SOME UNCERTAINTY WED INTO THURS WITH A DEVELOPING SURFACE LOW
OFF THE MID ATLANTIC COAST. MODELS ARE BEGINNING TO COME MORE INTO
LINE WITH THIS LOW DEVELOPING TUES NIGHT AND PASS TO THE SOUTH AND
EAST OF THE CWA. THIS PATH WOULD LEND TO THE IDEA OF THE PRECIP
STAYING MORE TO THE SOUTH...HOWEVER...THE UPPER LEVEL TROUGH BEGINS
TO MOVE THE NORTHEAST...WHICH MAY AID IN SOME DEVELOPING PRECIP WED.
OVERALL THOUGH...CONFIDENCE NOT GREAT AT THIS TIME THAT ANYTHING
WILL DEVELOP...ESP OVER THE NORTHERN FRINGES OF THE CWA...SO WILL GO
WITH SLIGHT CHC POPS. IF THE LOW EDGES MORE TO THE NORTH...THEN WE
COULD SEE MORE SCT ACTIVITY DURING THE DAY WED. WITH THE EASTERLY TO
NORTHEASTERLY FLOW...ONCE AGAIN ANY PRECIP LOOKS TO BE MORE JUST
RAIN SHOWERS...WITH AN ISO THREAT OF THUNDER.
END OF THE WEEK...HIGH PRESSURE HIGH PRESSURE TAKES OVER AT THE
SURFACE. A MORE ZONAL FLOW DEVELOPS ALOFT...WITH MULTIPLE
DISTURBANCES POSSIBLE FOR THE WEEKEND WHICH COULD BRING MORE PRECIP
IN.
NEAR NORMAL TEMPERATURES EXPECTED FOR THE COMING WEEK...WITH GRADUAL
WARMING BY THE END OF THE WEEK WITH THE RETURN FLOW USHERING IN
WARMER AND MORE MOIST AIR.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
WEAK LOW PRESSURE PASSES WELL TO OUR SOUTH INTO THIS EVENING...A
WEAK TROUGH OF LOW PRESSURE BUILDS IN TONIGHT.
VFR THROUGH THE TAF PERIOD. LOOKING INCREASINGLY LIKE MOST IF NOT
ALL THE AREA WILL STAY DRY. BEST CHANCE OF ANY PRECIPITATION IS OVER
FAR WESTERN TERMINALS THIS AFTERNOON/EARLY THIS EVENING WHERE THERE
COULD BE A PASSING SHOWER. HAVE A PROB30 IN AT KSWF FOR NOW. AT
REMAINDER OF TERMINALS CHANCE OF PRECIPITATION IS 20 PERCENT OR LESS.
MAINLY LIGHT AND VARIABLE WINDS THROUGH THE TAF PERIOD. COASTAL
TERMINALS COULD SEE A BRIEF PERIOD OF SEA BREEZE INFLUENCE THIS
AFTERNOON. CONFIDENCE IN ANY WIND DIRECTION FORECAST IS LOW.
OUTLOOK FOR 06Z TUESDAY THROUGH FRIDAY...
.LATE MONDAY NIGHT-FRIDAY...MOST LIKELY VFR. SMALL CHANCE MVFR OR
LOWER TUESDAY NIGHT-WEDNESDAY NIGHT DEPENDING ON EXACT TRACK OF A
LOW FORECAST TO PASS TO THE SE OF LONG ISLAND.
&&
.MARINE...
HIGH PRESSURE OVER THE AREA WATERS WEAKENS TONIGHT. A WEAK AREA
OF LOW PRESSURE WILL PASS SOUTHEAST OF THE WATERS DURING THE DAY
MONDAY AND INTO MONDAY NIGHT. THIS WILL ALLOW SEAS TO
INCREASE...BUT WILL REMAIN BELOW SMALL CRAFT LEVELS. SEAS ARE
EXPECTED TO BUILD TO 3 TO 4 FT.
MAINLY SUB-SCA CONDITIONS EXPECTED FOR THE WEEK INTO THE COMING
WEEKEND WITH A WEAK PRESSURE GRADIENT REMAINING OVER THE REGION. THE
ONE THING TO WATCH IS THE TRACK OF THE POTENTIAL COASTAL LOW MID
WEEK...WHICH COULD PRODUCE GUSTS UP TO 25 KTS IF IT MOVES FARTHER TO
THE NORTH.
&&
.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH THE WEEK.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BC/SEARS
NEAR TERM...BC/JMC/JM
SHORT TERM...BC
LONG TERM...SEARS
AVIATION...MALOIT
MARINE...BC/SEARS
HYDROLOGY...BC/SEARS
AREA FORECAST DISCUSSION
NWS ALBANY NY
130 AM EDT MON AUG 20 2012
.SYNOPSIS...
A SURFACE LOW PRESSURE SYSTEM WILL MOVE OFF THE MID
ATLANTIC COAST TODAY...WHILE AN UPPER LEVEL TROUGH WILL BEGIN TO
SLOWLY MOVE EAST FROM THE GREAT LAKES. THESE TWO SYSTEMS WILL ALLOW
FOR SOME ISOLATED TO SCATTERED RAIN SHOWERS TO THE REGION OVER THE
NEXT FEW DAYS...ALTHOUGH MOST AREAS LOOK TO STAY DRY FOR MUCH OF THE
TIME. HIGH PRESSURE WILL RETURN TO THE REGION FOR THE MIDDLE TO
LATTER PORTION OF THE WEEK WITH CONTINUED COMFORTABLE TEMPERATURES.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
AS OF 124 AM EDT...WEAK HIGH PRESSURE OVER NEW JERSEY HAS BEGUN TO
SHIFT OFFSHORE. ALTHOUGH THERE WERE SOME HIGH CLOUDS
EARLIER...ENOUGH CLEARING HAS TAKEN PLACE ACROSS CENTRAL/NORTHERN
PARTS OF THE AREA TO ALLOW FOR DECENT RADIATIONAL COOLING EARLY
THIS MORNING. THIS WILL LEAD TO SOME PATCHY FOG DEVELOPMENT
OVERNIGHT. SOUTHERN/SOUTHEASTERN AREAS MAY NOT SEE AS MUCH
FOG...AS ANOTHER BATCH OF CLOUDS IS HEADED UP FROM PA/NJ...AND
THIS WILL LEAD TO A MOSTLY CLOUDY SKY BY THE LATE NIGHT HOURS.
DESPITE SOME SHOWERS WELL TO OUR WEST ACROSS WESTERN NEW YORK...IT
SHOULD REMAIN DRY OVER OUR ENTIRE AREA THROUGH THE REMAINDER OF
THE OVERNIGHT HOURS...AND THE LATEST 00 UTC NAM AND 3KM HRRR AGREE
WITH THIS IDEA. MIN TEMPS STILL APPEAR ON TRACK WITH MINS RANGING
FROM THE LOWER/MID 40S IN THE ADIRONDACKS TO THE MID 50S IN THE
HUDSON VALLEY.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH TUESDAY NIGHT/...
MODELS ARE NOW FORECASTING THE MOISTURE ASSOCIATED WITH THE FRONTAL
WAVE TO REMAIN SOUTH AND EAST OF THE FORECAST ON MONDAY...BUT
SHOWERS ARE STILL POSSIBLE MONDAY AND MONDAY NIGHT AS THE UPPER
LEVEL TROF OVER THE OHIO VALLEY AFFECTS THE REGION. HOWEVER...WITH
THE MORE ORGANIZED AREA OF MOISTURE REMAINING TO THE EAST...WILL
ONLY FORECAST POPS IN THE LOW CHANCE RANGE (AROUND 30 PERCENT)...
WITH MOSTLY CLOUDY SKIES. HIGHS MONDAY WILL BE IN THE 70S...AND LOWS
MONDAY NIGHT GENERALLY IN THE 50S.
EVEN THOUGH THE COASTAL MOISTURE IS LONG GONE FROM THE REGION ON
TUESDAY...THE UPPER LEVEL TROF IS FORECAST TO CONTINUE TO LAG OVER
THE OHIO VALLEY...SO HAVE FORECAST A SLIGHT CHANCE FOR SHOWERS OR A
THUNDERSTORM TUESDAY AFTN AND EVENING. SKIES WILL BE PARTLY CLOUDY
TUESDAY AND TUESDAY NIGHT WITH HIGHS IN THE 70S TO LOWER 80S
TUESDAY. LOWS TUESDAY NIGHT WILL BE IN THE 40S NORTH AND 50S SOUTH.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
MUCH OF LONG TERM PERIOD LOOKS LIKE IT WILL BE RATHER TRANQUIL
ACROSS EASTERN NEW YORK AND WESTERN NEW ENGLAND WITH GENERALLY
SEASONABLE TEMPS...PERHAPS WARMING TO ABOVE NORMAL BY NEXT WEEKEND.
WILL ONLY MENTION A SLIGHT CHANCE POPS ON WEDNESDAY...AS A LINGERING
WEAK FRONTAL BOUNDARY MAY TRIGGER A FEW POP-UP SHOWERS OVER THE
SOUTHERN HALF OF THE AREA. WEAK LIFT SHOULD PRECLUDE MORE WIDESPREAD
SHOWER DEVELOPMENT.
HIGH PRESSURE WILL THEN BUILD IN AND TAKE RESIDENCE ACROSS THE
REGION THROUGH THE REST OF THE WORK WEEK...BRINGING DRY CONDITIONS
AND COMFORTABLE HUMIDITY LEVELS. HIGH PRESSURE MAY LINGER THROUGH
THE WEEKEND KEEPING RAIN-FREE CONDITIONS GOING...ALTHOUGH MODELS
SHOWING A WARMING TREND WITH POSSIBLE INCREASING HUMIDITY.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
SATELLITE IMAGERY THIS EARLY MONDAY MORNING REVEALS AMPLE BREAKS
INBETWEEN THE SCT-BKN HIGH AND MID LEVEL CLOUDS. THIS HAS ALLOWED
FOR DEWPOINT DEPRESSIONS TO BECOME QUITE CLOSE FOR SOME MVFR/IFR
CONDITIONS AT KGFL-KPSF AND MAYBE EVEN KPOU. WE WILL MENTION A
TEMPO GROUP FOR MVFR/IFR VSBY FOR NOW...AND MONITOR TRENDS CLOSELY.
ELSEWHERE CLOUDS SHOULD THICKEN QUICKLY ENOUGH TO PRECLUDE FOG
FORMATION.
CIGS WILL GRADUALLY LOWER MONDAY MORNING AND ESPECIALLY DURING THE
AFTERNOON. HOWEVER CIGS ARE EXPECTED TO REMAIN IN VFR RANGE.
SCATTERED SHOWERS WILL DEVELOP AROUND THE NOON HOUR AND GRADUALLY
SPREADING NORTHWARD DURING THE AFTERNOON. DUE TO EXPECTED SCATTERED
COVERAGE WILL MENTION VCSH AT ALL TERMINALS BY 18Z MONDAY.
WINDS WILL BE RATHER LIGHT...LESS THAN 10 KTS...THROUGH THE FORECAST
PERIOD.
OUTLOOK...
TUE-WED...VFR. SLIGHT CHC -SHRA.
THU-FRI...VFR. NO SIG WX.
&&
.FIRE WEATHER...
HIGH PRESSURE WILL MOVE OFF THE COAST TONIGHT. A SURFACE LOW
PRESSURE SYSTEM WILL MOVE OFF THE MID ATLANTIC COAST ON
MONDAY...WHILE AN UPPER LEVEL TROUGH WILL MOVE EAST FROM THE GREAT
LAKES. THESE TWO SYSTEMS WILL BRING A CHANCE OF SHOWERS TO THE
REGION MONDAY AND MONDAY NIGHT.
TONIGHT...THOSE RELATIVE HUMIDITIES WILL RECOVER TO GREATER THAN 90
PERCENT. WINDS WILL BE LIGHT AND VARIABLE.
MONDAY...CLOUDS ALONG WITH THE POTENTIAL FOR SHOWERS WILL KEEP
MINIMUM RELATIVE HUMIDITIES BETWEEN 45 AND 65 PERCENT. WINDS WILL
BE SOUTHERLY AT LESS THAN 10 MPH.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED FOR THE NEXT FIVE DAYS.
DRY THROUGH TONIGHT...THEN SCATTERED SHOWERS MONDAY AND MONDAY
NIGHT...BUT BASIN AVERAGE RAINFALL AMOUNTS ARE FORECAST TO BE UNDER
A THIRD OF AN INCH WHICH WILL HAVE LITTLE OR NO IMPACT ON AREA
STREAMS AND RIVERS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...GJM
LONG TERM...JPV
AVIATION...BGM
FIRE WEATHER...GJM
HYDROLOGY...GJM
AREA FORECAST DISCUSSION
NWS ALBANY NY
124 AM EDT MON AUG 20 2012
.SYNOPSIS...
A SURFACE LOW PRESSURE SYSTEM WILL MOVE OFF THE MID
ATLANTIC COAST TODAY...WHILE AN UPPER LEVEL TROUGH WILL BEGIN TO
SLOWLY MOVE EAST FROM THE GREAT LAKES. THESE TWO SYSTEMS WILL ALLOW
FOR SOME ISOLATED TO SCATTERED RAIN SHOWERS TO THE REGION OVER THE
NEXT FEW DAYS...ALTHOUGH MOST AREAS LOOK TO STAY DRY FOR MUCH OF THE
TIME. HIGH PRESSURE WILL RETURN TO THE REGION FOR THE MIDDLE TO
LATTER PORTION OF THE WEEK WITH CONTINUED COMFORTABLE TEMPERATURES.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
AS OF 124 AM EDT...WEAK HIGH PRESSURE OVER NEW JERSEY HAS BEGUN TO
SHIFT OFFSHORE. ALTHOUGH THERE WERE SOME HIGH CLOUDS
EARLIER...ENOUGH CLEARING HAS TAKEN PLACE ACROSS CENTRAL/NORTHERN
PARTS OF THE AREA TO ALLOW FOR DECENT RADIATIONAL COOLING EARLY
THIS MORNING. THIS WILL LEAD TO SOME PATCHY FOG DEVELOPMENT
OVERNIGHT. SOUTHERN/SOUTHEASTERN AREAS MAY NOT SEE AS MUCH
FOG...AS ANOTHER BATCH OF CLOUDS IS HEADED UP FROM PA/NJ...AND
THIS WILL LEAD TO A MOSTLY CLOUDY SKY BY THE LATE NIGHT HOURS.
DESPITE SOME SHOWERS WELL TO OUR WEST ACROSS WESTERN NEW YORK...IT
SHOULD REMAIN DRY OVER OUR ENTIRE AREA THROUGH THE REMAINDER OF
THE OVERNIGHT HOURS...AND THE LATEST 00 UTC NAM AND 3KM HRRR AGREE
WITH THIS IDEA. MIN TEMPS STILL APPEAR ON TRACK WITH MINS RANGING
FROM THE LOWER/MID 40S IN THE ADIRONDACKS TO THE MID 50S IN THE
HUDSON VALLEY.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH TUESDAY NIGHT/...
MODELS ARE NOW FORECASTING THE MOISTURE ASSOCIATED WITH THE FRONTAL
WAVE TO REMAIN SOUTH AND EAST OF THE FORECAST ON MONDAY...BUT
SHOWERS ARE STILL POSSIBLE MONDAY AND MONDAY NIGHT AS THE UPPER
LEVEL TROF OVER THE OHIO VALLEY AFFECTS THE REGION. HOWEVER...WITH
THE MORE ORGANIZED AREA OF MOISTURE REMAINING TO THE EAST...WILL
ONLY FORECAST POPS IN THE LOW CHANCE RANGE (AROUND 30 PERCENT)...
WITH MOSTLY CLOUDY SKIES. HIGHS MONDAY WILL BE IN THE 70S...AND LOWS
MONDAY NIGHT GENERALLY IN THE 50S.
EVEN THOUGH THE COASTAL MOISTURE IS LONG GONE FROM THE REGION ON
TUESDAY...THE UPPER LEVEL TROF IS FORECAST TO CONTINUE TO LAG OVER
THE OHIO VALLEY...SO HAVE FORECAST A SLIGHT CHANCE FOR SHOWERS OR A
THUNDERSTORM TUESDAY AFTN AND EVENING. SKIES WILL BE PARTLY CLOUDY
TUESDAY AND TUESDAY NIGHT WITH HIGHS IN THE 70S TO LOWER 80S
TUESDAY. LOWS TUESDAY NIGHT WILL BE IN THE 40S NORTH AND 50S SOUTH.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
MUCH OF LONG TERM PERIOD LOOKS LIKE IT WILL BE RATHER TRANQUIL
ACROSS EASTERN NEW YORK AND WESTERN NEW ENGLAND WITH GENERALLY
SEASONABLE TEMPS...PERHAPS WARMING TO ABOVE NORMAL BY NEXT WEEKEND.
WILL ONLY MENTION A SLIGHT CHANCE POPS ON WEDNESDAY...AS A LINGERING
WEAK FRONTAL BOUNDARY MAY TRIGGER A FEW POP-UP SHOWERS OVER THE
SOUTHERN HALF OF THE AREA. WEAK LIFT SHOULD PRECLUDE MORE WIDESPREAD
SHOWER DEVELOPMENT.
HIGH PRESSURE WILL THEN BUILD IN AND TAKE RESIDENCE ACROSS THE
REGION THROUGH THE REST OF THE WORK WEEK...BRINGING DRY CONDITIONS
AND COMFORTABLE HUMIDITY LEVELS. HIGH PRESSURE MAY LINGER THROUGH
THE WEEKEND KEEPING RAIN-FREE CONDITIONS GOING...ALTHOUGH MODELS
SHOWING A WARMING TREND WITH POSSIBLE INCREASING HUMIDITY.
&&
.AVIATION /05Z MONDAY THROUGH FRIDAY/...
WEAK HIGH PRESSURE WILL GRADUALLY MOVE OFF SHORE TONIGHT INTO
MONDAY...AND WILL BE REPLACED BY A WEAK TROUGH. MID/HIGH LEVEL
CLOUDS WILL GRADUALLY INCREASE AND THICKEN TONIGHT...ESPECIALLY
AFTER MIDNIGHT. VFR CONDITIONS ARE EXPECTED TO PREVAIL...ALTHOUGH
SINCE CLOUDS WILL BE INCREASING FROM SW-NE ACROSS THE AREA KGFL
COULD REMAIN CLEAR LONG ENOUGH FOR SOME FOG OR MIST TO FORM. WILL
MENTION MVFR VSBY FOR NOW...AS FOG POTENTIAL IS UNCERTAIN.
ELSEWHERE CLOUDS SHOULD THICKEN QUICKLY ENOUGH TO PRECLUDE FOG
FORMATION.
CIGS WILL GRADUALLY LOWER MONDAY MORNING AND ESPECIALLY DURING THE
AFTERNOON. HOWEVER CIGS ARE EXPECTED TO REMAIN IN VFR RANGE.
SCATTERED SHOWERS WILL DEVELOP STARTING NEAR KPOU IN THE MORNING
AND GRADUALLY SPREADING NORTHWARD DURING THE AFTERNOON. DUE TO
EXPECTED SCATTERED COVERAGE WILL MENTION VCSH AT ALL TERMINALS BY
18Z MONDAY.
OUTLOOK...
TUE-WED...VFR. SLIGHT CHC -SHRA.
THU-FRI...VFR. NO SIG WX.
&&
.FIRE WEATHER...
HIGH PRESSURE WILL MOVE OFF THE COAST TONIGHT. A SURFACE LOW
PRESSURE SYSTEM WILL MOVE OFF THE MID ATLANTIC COAST ON
MONDAY...WHILE AN UPPER LEVEL TROUGH WILL MOVE EAST FROM THE GREAT
LAKES. THESE TWO SYSTEMS WILL BRING A CHANCE OF SHOWERS TO THE
REGION MONDAY AND MONDAY NIGHT.
TONIGHT...THOSE RELATIVE HUMIDITIES WILL RECOVER TO GREATER THAN 90
PERCENT. WINDS WILL BE LIGHT AND VARIABLE.
MONDAY...CLOUDS ALONG WITH THE POTENTIAL FOR SHOWERS WILL KEEP
MINIMUM RELATIVE HUMIDITIES BETWEEN 45 AND 65 PERCENT. WINDS WILL
BE SOUTHERLY AT LESS THAN 10 MPH.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED FOR THE NEXT FIVE DAYS.
DRY THROUGH TONIGHT...THEN SCATTERED SHOWERS MONDAY AND MONDAY
NIGHT...BUT BASIN AVERAGE RAINFALL AMOUNTS ARE FORECAST TO BE UNDER
A THIRD OF AN INCH WHICH WILL HAVE LITTLE OR NO IMPACT ON AREA
STREAMS AND RIVERS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...GJM
LONG TERM...JPV
AVIATION...JPV
FIRE WEATHER...GJM
HYDROLOGY...GJM
AREA FORECAST DISCUSSION
NWS TAUNTON MA
122 AM EDT MON AUG 20 2012
.SYNOPSIS...
A FEW SHOWERS MAY GRAZE SOUTHEAST NEW ENGLAND MON AND MON NIGHT AS
LOW PRESSURE PASSES WELL SOUTHEAST OF THE REGION. OTHERWISE...A
RIDGE OF HIGH PRESSURE WILL BRING MAINLY DRY AND SEASONABLE WEATHER
RIGHT THROUGH NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
120 AM UPDATE...
HIGH CLOUD SHIELD WILL BECOME FOCUSED NEAR S COAST EARLY THIS
MORNING AS MOISTURE CONTINUES TO STREAM UP EAST COAST. RADAR
MOSAIC SHOWS A FEW SHOWERS LIFTING NE FROM OFF MID ATLANTIC COAST
WHICH HRRR BRINGS CLOSE TO NANTUCKET AROUND DAYBREAK...THOUGH MOST
OF ACTIVITY SHOULD REMAIN OFFSHORE.
ADJUSTED LOW TEMPERATURES SLIGHTLY UPWARD DUE TO FAIRLY THICK MID
AND HIGH CLOUD COVER.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
12Z GFS/ECMWF/CMC MODELS ALL ARE FARTHER SOUTHEAST WITH THE LOW
PRESSURE AREA DEVELOPING TO OUR SOUTH...PASSING WELL TO THE SOUTH
OF NANTUCKET LATER MON AFTERNOON. THEY ALL CONFINE MEASURABLE
PRECIPITATION TO A LINE FROM NEAR THE CAPE COD CANAL TO SOUTHERN RI.
ONLY THE 12Z NAM WOULD BRING LIGHT PRECIPITATION AS FAR NORTH AS
THE NH BORDER DURING THE DAY...BUT IT IS NOTED THAT THE NAM
AVIATION CEILING FORECAST IN THOSE AREAS IS 10000 FT...SO IF IT IS
TRUE...AT BEST WOULD ONLY EXPECT A HUNDREDTH OR TWO. MOST
IMPORTANTLY...WATER VAPOR SATELLITE IMAGERY TRENDS HAVE BEEN SHOWING
THE WESTERN EDGE OF CLOUDINESS SLIDING SLOWLY BUT STEADILY
EASTWARD...WHICH WOULD LEND CREDENCE TO THE GFS/ECMWF/CMC SOLUTIONS.
AS A RESULT...HAVE GONE WITH PARTLY TO MOSTLY CLOUDY SKIES IN THE
NW WITH VERY LOW POPS... AND CLOUDY SKIES WITH A LOW CHANCE OF
SHOWERS ELSEWHERE...EXCEPT AND SHOWERS LIKELY ON CAPE COD AND THE
ISLANDS.
THERE IS ALSO A COLD FRONT DROPPING SE FROM UPSTATE NY AND
NORTHERN NEW ENGLAND AND A WEAK VORTICITY MAX APPROACHING WESTERN
MA. THIS MAY TRIGGER WIDELY SCATTERED SHOWERS IN FAR WESTERN AREAS
TOWARD EVENING...BUT BEST CHANCE IS IN NY STATE.
MAVMOSGUID BIAS CORRECTED GRIDS AGAIN USED FOR HIGHS MON...MAINLY
UPPER 70S TO NEAR 80...WARMEST IN THE MERRIMACK AND CONNECTICUT
VALLEYS. HIGHS ONLY MID 70S CAPE COD AND ISLANDS WHERE CLOUDIER WITH
BETTER SHOWER PROBABILITIES.
MONDAY NIGHT...ANY SHOWERS WILL HAVE MOVED WELL OFFSHORE BY EARLY
EVENING. WEAK LOW PRESSURE TROUGH/REMNANTS OF A COLD FRONT MOVES
THROUGH BUT ITS PASSAGE SHOULD BE RELATIVELY BENIGN. PARTLY TO
MOSTLY CLOUDY SKIES AND LOWS MAINLY 55 TO 60.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
HIGHLIGHTS...
* MAINLY DRY AND SEASONABLE INTO NEXT WEEKEND
DETAILS...
TUESDAY THROUGH SUNDAY...
A RIDGE OF HIGH PRESSURE SHOULD RESULT IN MAINLY DRY AND SEASONABLE
WEATHER RIGHT THROUGH NEXT WEEKEND. WE CAN/T COMPLETELY RULE OUT A
DIURNALLY DRIVEN ISOLATED BRIEF SHOWER OR TWO AT TIMES...BUT AREAL
COVERAGE/DURATION WOULD LIKELY BE QUITE LIMITED. WE WILL HAVE TO
WATCH A FEW WAVES OF LOW PRESSURE THAT WILL PROBABLY TRACK SOUTHEAST
OF THE BENCHMARK OVER THIS PERIOD. THIS SHOULD KEEP MOST OF THE
PRECIPITATION TO THE SOUTH OF OUR REGION...ALTHOUGH A FEW SHOWERS
MAY GRAZE OUR REGION WED/WED NIGHT IF ONE LOW PRESSURE GETS CLOSE
ENOUGH BUT THAT IS UNCERTAIN. BEST CHANCE WOULD BE NEAR THE SOUTH
COAST.
HIGHS SHOULD MAINLY BE IN THE UPPER 70S AND LOWER 80S MOST OF THE
PERIOD...WITH SOME LOCATIONS PERHAPS REACHING INTO THE MIDDLE 80S
THU/FRI. RELATIVE HUMIDITY LEVELS WILL REMAIN COMFORTABLE FOR
OUTDOOR ACTIVITIES.
&&
.AVIATION /05Z MONDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
OVERVIEW...
HIGH CONFIDENCE IN TAFS. MVFR CIGS POSSIBLE AROUND CAPE COD AND
ISLANDS THIS AFTERNOON BUT PROBABILITY WAS TOO LOW TO INCLUDE IN
TAFS FOR KACK/KHYA/KACK. COULD SEE BRIEF LIGHT SHOWER/SPRINKLES
NEAR KACK AROUND DAYBREAK BUT LIGHT SHOWERS MORE LIKELY TO AFFECT
KACK AFTER 17Z. MAY ALSO REACH KFMH/KHYA. ISOLD SHOWER ALSO
POSSIBLE ACROSS INTERIOR THIS AFTERNOON...ESPECIALLY NEAR
BERKSHIRES AND MONADNOCKS BUT SHOULD REMAIN VFR.
LOCAL MVFR/IFR POSSIBLE IN PATCHY FOG TONIGHT ACROSS INTERIOR.
ISOLD SHOWER POSSIBLE AGAIN TUE OVER MOST OF SOUTHERN NEW ENGLAND
BUT NOT EXPECTING CONDITIONS TO DROP BELOW VFR.
KBOS TAF...HIGH CONFIDENCE IN TAF...INCLUDING SEA BREEZE TIMING.
KBDL TAF...HIGH CONFIDENCE IN TAF.
OUTLOOK...WEDNESDAY THROUGH FRIDAY...
MODERATE TO HIGH CONFIDENCE. MAINLY VFR CONDITIONS OTHER THAN
PATCHY FOG AT TIMES IN THE PARTICULARLY PRONE LOCATIONS DURING THE
OVERNIGHT/EARLY MORNING HOURS.
&&
.MARINE...
HIGH CONFIDENCE THROUGH MONDAY NIGHT. WINDS AND SEAS BELOW SMALL
CRAFT ADVISORY THRESHOLDS THROUGH THE PERIOD. SEAS WILL BE
BUILDING FROM 1 FT TONIGHT TO CLOSER TO 3 TO 4 FT BY MONDAY NIGHT
OVER THE OUTER WATERS AS LOW PRESSURE TRACKS TO THE SOUTH OF THE
40/70 BENCHMARK.
OUTLOOK...TUESDAY THROUGH FRIDAY...
HIGH CONFIDENCE THAT WINDS AND SEAS SHOULD GENERALLY REMAIN BELOW
SMALL CRAFT ADVISORY CRITERIA THROUGH THE PERIOD WITH A WEAK
PRESSURE GRADIENT IN PLACE.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...FRANK/GAF
NEAR TERM...JWD
SHORT TERM...GAF
LONG TERM...FRANK
AVIATION...JWD
MARINE...FRANK/GAF
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1158 PM CDT SUN AUG 19 2012
.UPDATE...
ISSUED AT 1158 PM CDT SUN AUG 19 2012
STILL FIGHTING ISOLATED LIGHT SHOWERS OVER SOUTHEAST MISSOURI INTO
THE PURCHASE AREA OF WEST KENTUCKY. STILL EXPECTING THEM TO GO
AWAY AND FOR SKIES TO CLEAR OVERNIGHT. IN AREAS THAT RECEIVED RAIN
TODAY...DECIDED TO ADD A MENTION OF PATCHY DENSE FOG.
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 06Z TAF ISSUANCE.
UPDATE ISSUED AT 946 PM CDT SUN AUG 19 2012
SCATTERED SHOWERS OVER SOUTHEAST MISSOURI HAVE BEEN RATHER
RESILIENT THIS EVENING. UPDATED THE FORECAST FOR THE THIRD TIME TO
ACCOUNT FOR THEM...AND THIS TIME ENDED UP SPREADING ISOLATED SHOWERS
INTO THE PURCHASE AREA OF WEST KENTUCKY FOR THE NEXT HOUR OR TWO.
HOWEVER...WITH NICE OUTFLOW NOTED ON RADAR...IT APPEARS THEY ARE
FINALLY ON A DOWNWARD TREND.
IN RESPONSE TO THE SHOWERS DEWPOINTS HAVE JUMPED INTO THE
60S...WHICH MAY RESULT IN MILDER LOWS OVER MUCH SOUTHEAST
MISSOURI. THE RUC HAS A DECENT HANDLE ON THE SITUATION...SO
FOLLOWED IT PRETTY CLOSELY. THIS ALSO RESULTED IN A SLIGHT LOWERING
OF LOWS IN THE KEVV AREA.
THE AVIATION SECTION HAS ALSO BEEN UPDATED FOR THE IMPACT OF THE
SHOWERS AT KCGI
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 303 PM CDT SUN AUG 19 2012
BASED GENERALLY ON SAME REASONING AS IN THE UPDATE SECTION ABOVE...
AM INCLINED TO REDUCE SHOWER/STORM CHANCES DOWN TO AROUND 10
PERCENT FOR MONDAY/TUE ALSO. AGAIN...EVEN THO WEAK IMPULSES ALOFT
WILL CONTINUE TO ROTATE SSE WITHIN FAIRLY DEEP TROF /CYCLONIC FLOW/
OVER THE OHIO VALLEY...THERE JUST SEEMS TO BE VERY LITTLE
INSTABILITY AND OVERALL MOISTURE TO WORK WITH///ESP IN THE LOWEST
7000 TO 10000 FT. CANNOT RULE OUT AN ISOLD SHOWER OR SPRINKLES HERE
AND THERE...BUT CAPES PROGGED TO REMAIN LESS THAN 400 J/KG FOR THE
MOST PART THROUGH TUE...SO THUNDER CHCS CONTINUE TO LOOK PRACTICALLY
NIL.
AS FAR AS TEMPS ARE CONCERNED...WILL CONT TO IGNORE THE OBVIOUSLY
COLD MAV TEMP BIAS. EVEN THE MET MOS TEMPS SEEM TO BE RUNNING A
FEW DEGREES TOO COOL TODAY. HOWEVER...GIVEN THE FACT THAT THERE
MAY BE MORE IN THE WAY OF MID CLOUDS MONDAY...WILL STAY CLOSE TO
THE MET MOS NUMBERS TONIGHT THROUGH TUE NIGHT.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 303 PM CDT SUN AUG 19 2012
FOR WEDNESDAY THROUGH THURSDAY NIGHT...MODELS SHOW A BROAD UPPER
LEVEL RIDGE OVER THE REGION WITH HIGH PRESSURE AT THE SURFACE. THIS
WILL KEEP CONDITIONS DRY ACROSS THE PAH FORECAST AREA. SOUTHERLY
FLOW AND PLENTY OF SUNSHINE WILL KEEP TEMPERATURES NEAR NORMAL WITH
HIGHS IN THE UPPER 80S AND LOWS IN THE LOWER TO MIDDLE 60S.
MODELS DIVERGE ON FRIDAY. THE 00Z ECMWF SHOWED AN UPPER LEVEL LOW
SLIDING INTO THE AREA...BRINGING SOME QPF TO MAINLY SOUTHERN
PORTIONS OF THE PAH FORECAST AREA. THE 12Z ECMWF IS MUCH LESS
PRONOUNCED WITH THIS FEATURE AND KEEPS ANY PRECIP JUST WEST OF OUR
AREA. THE LATEST GFS...ON THE OTHER HAND...BRINGS A SURFACE LOW OUT
OF THE PLAINS AND BRINGS CHANCES OF PRECIP INTO OUR WESTERN COUNTIES
FRIDAY NIGHT AND THE ENTIRE PAH FA ON SATURDAY. MODELS LACK ANY
REAL CONSISTENCY...SO JUST STUCK WITH SLIGHT TO VERY LOW CHANCE
POPS FOR NOW...WITH SLIGHTLY HIGHER POPS ACROSS OUR SOUTHERN
COUNTIES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1158 PM CDT SUN AUG 19 2012
VLIFR FOG WILL BE POSSIBLE AT KCGI DUE TO THE TENTH OF AN INCH OF
RAIN THEY GOT THIS EVENING...AND CLEARING SKIES OVERNIGHT. STILL
HAVE SOME LIGHT SHOWERS EFFECTING KPAH...SO KEPT A VFR SHOWER
MENTIONED FOR A FEW HOURS.
THE NEXT IMPULSE DIVING INTO THE BASE OF THE TROUGH OVER THE AREA
MAINLY MONDAY EVENING. BASED ON THE COVERAGE TODAY AND SIMILAR
LOOKING DATA FOR MONDAY...DECIDED TO MENTION A VCSH AT KEVV AND
KOWB.
&&
.FIRE WEATHER...
ISSUED AT 303 PM CDT SUN AUG 19 2012
VERY DRY AIR WILL REMAIN IN PLACE FOR THE FIRST HALF OF THE
UPCOMING WEEKS. IN FACT...SOME LOCATIONS MAY SEE RELATIVE
HUMIDITIES DIP TO NEAR 20 PERCENT BY TUESDAY. IN ADDITION...10
HOUR FUEL MOISTURES HAVE NOW FALLEN BACK INTO THE 6 TO 10 PERCENT
RANGE. THUS...THE RISK OF RAPID WILDFIRE GROWTH WILL BE ELEVATED
DURING THIS TIME FRAME. WINDS...BOTH AT THE SURFACE AND ALOFT...
SHOULD REMAIN GENERALLY LIGHT.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...MEFFERT
LONG TERM....RST
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1231 AM EDT MON AUG 20 2012
.SYNOPSIS...
A SERIES OF WEAK UPPER LEVEL DISTURBANCES WILL CROSS THE UPPER
OHIO VALLEY EARLY THIS WEEK AND GENERATE A FEW SHOWERS AND
POSSIBLY A THUNDERSTORM. HIGH PRESSURE WILL MOVE INTO THE AREA ON
WEDNESDAY...RETURNING DRY WEATHER FOR THE MID-WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
UPDATED NEAR TERM TO KEEP CHANCE POPS AND AN ISOLATED THUNDER
MENTION FOR THE NEXT FEW HOURS AS SHOWERS AND A FEW THUNDERSTORMS
CROSS INTO WESTERN PENNSYLVANIA WITH SUPPORT FROM AN UPPER LEVEL
SHORTWAVE. THUNDERSTORMS SHOULD REMAIN ELEVATED BASED ON THE
BUFKIT SOUNDINGS. CLOUD COVER SHOULD HELP TO KEEP TEMPERATURES A
BIT WARMER THAN GUIDANCE OVERNIGHT. BUMPED UP TEMPERATURES A
DEGREE OR TWO. STILL SOME PATCHY FOG WILL BE POSSIBLE...ESPECIALLY
IN LOCATIONS THAT RECEIVE RAINFALL.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
THERE IS ECMWF/GFS/NAM AGREEMENT THAT THE BROAD MID-LEVEL TROUGH
WILL REMAIN ACROSS THE OHIO VALLEY ON MONDAY AND AMPLIFY AS ITS
AXIS SWINGS INTO THE UPPER OHIO VALLEY LATE TUESDAY INTO
WEDNESDAY. WITH THE UPPER OHIO VALLEY IN A SOUTHWESTERLY FLOW
AHEAD OF THIS FEATURE AND THE MAJORITY OF MODEL SOLUTIONS SHOWING
WEAK INSTABILITY EACH DAY, CHC POPS WITH SCHC THUNDER IS FORECAST
FOR MONDAY WITH SCHC POPS/THUNDER ON TUESDAY. TEMPS WILL BE AROUND
5 DEGREES BELOW NORMAL THROUGH THIS PERIOD.
A MODEL CONSENSUS INDICATES THE TROUGH SLIDING EAST OF AREA AND
HIGH PRESSURE BUILDING IN FROM THE WEST ON WEDNESDAY. THIS WILL
ALLOW FOR A DRY FORECAST WITH MORE ABUNDANT SUNSHINE ON WEDNESDAY.
WITH INCREASED SUNSHINE TEMPS WILL WARM CLOSER TO SEASONAL NORMALS
ACROSS THE AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
CONSENSUS OF RECENT ECMWF AND NAEFS MODEL OUTPUT CONTINUES TO SHOW
BROAD HIGH PRESSURE UNDER WEAK FLOW ALOFT ACROSS THE EASTERN U.S.
INTO THE WEEKEND. HENCE, WILL MAINTAIN A FORECAST OF DRY AND
RELATIVELY CLOUD FREE CONDITIONS THROUGH THE PERIOD.
THIS SHOULD TRANSLATE TO EACH DAY HAVING A LARGER THAN NORMAL
DIURNAL TEMPERATURE RANGE. CONCUR WITH HPC THINKING, WITH SUPPORT
FROM GFS AND ECMWF MOS AND NAEFS MEDIAN VALUES, THAT LOWS THURSDAY
AND FRIDAY CAN BE UP TO 5 DEGREES COOLER THAN NORMAL, WHILE HIGHS BE
NEAR NORMAL. WITH POTENTIAL OF SURFACE DEW POINTS CLIMBING TO NEAR
NORMAL VALUES THIS WEEKEND, EXPECT WEEKEND LOWS TO LIKEWISE BE NEAR
NORMAL, WHILE HIGHS BE UP TO 5 DEGREES WARMER THAN NORMAL.
&&
.AVIATION /04Z MONDAY THROUGH FRIDAY/...
EXPECT MAINLY VFR ACROSS THE UPPER OHIO VALLEY THROUGH 07Z.
PER BLEND OF RECENT RADAR DATA AND HRRR MODEL OUTPUT FORESEE ONLY
POTENTIAL OF RESTRICTIONS WOULD BE WITH ISOLATED SHOWERS AND
THUNDERSTORMS EARLY THIS EVENING.
LATEST GFS LAMP AND NAM MOS GUIDANCE FOR MOST TAF LOCATIONS
CONTINUES TO SHOW IFR RESTRICTIONS IN FOG 07Z-13Z. HOWEVER, AT
THIS JUNCTURE HAD ONLY ENOUGH CONFIDENCE TO INCLUDE MVFR
VISIBILITIES FOR MOST TAF SITES LATE TONIGHT...WITH A PERIOD OF
IFR AT KFKL AND KDUJ.
THE OTHER KEY TO FOG DEVELOPMENT LATE TONIGHT WOULD BE THE
LOCATION AND EXTENT OF SHOWERS EARLY TONIGHT AND THEIR SUBSEQUENT
EFFECT ON MOISTENING A SHALLOW TEMPERATURE-INVERSION CAPPED
SURFACE LAYER TONIGHT.
EXPECT THE REST OF MONDAY TO BE MAINLY VFR, ALTHOUGH AGAIN CANNOT
COMPLETELY RULE OUT THE POTENTIAL OF A BRIEF RESTRICTION WITH
ISOLATED AFTERNOON THUNDERSTORMS.
.OUTLOOK/ MONDAY NIGHT THROUGH FRIDAY/...
GENERALLY VFR CONDITIONS ARE EXPECTED. RESTRICTIONS MAY ACCOMPANY
SCATTERED THUNDERSTORMS MONDAY EVENING, AND PATCHY RIVER VALLEY
FOG EACH MORNING.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
147 AM EDT MON AUG 20 2012
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 332 PM EDT SUN AUG 19 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF OVER
ERN NAMERICA AND ARND CLOSED UPR LO NEAR JAMES BAY DOWNSTREAM OF UPR
RDG OVER THE ROCKIES. RUC ANALYSIS INDICATES A SHRTWV EMBEDDED
WITHIN THE UPR TROF IS OVER LK SUP. THIS DISTURBANCE/HINT OF SFC LO
PRES TROF SUPPORTED SOME SCT -SHRA MAINLY OVER CNTRL UPR MI INTO
EARLY AFTN. BUT DESPITE SOME SFC HEATING...THERE ARE NO MORE THAN
ISOLD -SHRA NOW OVER THE SCNTRL DESPITE SOME LK BREEZE CNVGC IN THAT
AREA. LLVL DRY AIR APPEARS TO BE THE MAIN LIMITING FACTOR AS SFC
DEWPTS HAVE MIXED OUT TO 40 TO 45 AT MOST SPOTS. ANOTHER STRONGER
DISTURBANCE ROTATING ARND THE PARENT UPR LO IS NOTED ON WV IMAGERY
OVER NRN ONTARIO. WHERE THE MSTR IS DEEPEST ON THE CYC SIDE OF THIS
FEATURE...THICK CLD COVER IS PRESENT OVER MUCH OF ONTARIO EXCEPT THE
FAR W. MUCH DRIER AIRMASS SHOWN ON THE 12Z INL/YPL RAOBS...WHERE
PWAT IS 0.38/0.41 INCH RESPECTIVELY OR NEAR 50 PCT OF NORMAL...IS
ALLOWING CLR-PCLDY CONDITIONS FM NRN MN THRU MOST OF WRN ONTARIO.
BUT THERE IS ANOTHER PATCH OF CLDS OVER FAR NW ONTARIO/ADJOINING
MANITOBA ASSOCIATED WITH YET ANOTHER SHRTWV DIVING SSEWD E OF LK
WINNIPEG WITHIN THE NNW FLOW ALF.
TONIGHT...EXPECT ANY LINGERING -SHRA OVER MAINLY THE SCNTRL TO END
THIS EVNG WITH EXIT OF SHRTWV NOW OVER LK SUP AND LOSS OF DAYTIME
HEATING. ALTHOUGH THE EVNG WL THEN TURN MOCLR EXCEPT FOR SOME PATCHY
HI CLDS WITH DRY AIR SHOWN ON THE 12Z INL/YPL RAOBS DOMINATING...
BULK OF GUIDANCE INDICATES SHRTWV NOW DIVING SWD THRU NRN ONTARIO WL
DIVE SWD TO NEAR ISLE ROYALE BY 12Z MON. SO EVEN THOUGH ALL MODELS
SHOW BULK OF THICKER CLD NOW DOMINATING MUCH OF ONTARIO ON THE CYC
SIDE OF SHRTWV TRACK WL REMAIN TO THE NE OF THE CWA UNDER LOWER H85
TEMPS...SUSPECT MORE CLDS WL ARRIVE OVER AT LEAST THE NRN TIER LATER
TNGT. WITH A PERIOD OF MOCLR SKIES THRU AT LEAST THE EVNG INTO EARLY
OVERNGT...EXPECT A QUICK DROP OF TEMPS. THE COOLEST OVERNGT MINS
INTO THE UPR 30S ARE MOST LIKELY OVER THE SRN TIER...WHERE MORE CLDS
ASSOCIATED WITH INCOMING SHRTWV ARE LIKELY NOT TO ARRIVE BEFORE
SUNRISE.
MON...INCOMING SHRTWV IS PROGGED TO SLIDE SWD ACRS WRN UPR MI AND
INTO WI IN THE AFTN. SINCE THE CWA WL BE ON THE CYC SIDE OF THE
TRACK OF THIS DISTURBANCE AND ACCOMPANYING DPVA/SOME DEEP LYR
QVECTOR CNVGC WL OCCUR DURING PEAK HEATING TIME...EXPECT AT LEAST
ISOLD -SHRA TO IMPACT MAINLY THE SCNTRL...WHERE SOME LK BREEZE CNVGC
MIGHT ENHANCE PCPN POTENTIAL. POPS WL BE LIMITED BY LLVL DRY AIR AND
LO KINX FCST NO HIER THAN 25 TO 30. WITH H85 TEMPS FCST IN THE 7 TO
9C RANGE...EXPECT HI TEMPS TO PEAK NOT FAR FM 70.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 332 PM EDT SUN AUG 19 2012
OVERALL GOOD MODEL AGREEMENT THROUGH WED...LEADING TO INCREASED
FORECAST CONFIDENCE FOR THIS TIME PERIOD.
STARTING THE PERIOD 00Z TUE...A SHORTWAVE TROUGH WILL BE EXITING THE
WA TO THE SE...ROTATING AROUND THE UPPER LEVEL LOW OVER NW QUEBEC
AND THE UPPER TROUGH OVER MUCH OF THE ERN HALF OF THE CONUS. THERE
MAY BE SOME SHOWERS EARLY ON MON NIGHT FROM THIS PASSING
THROUGH...BUT COVERAGE SHOULD BE LIMITED DUE TO THE DRY AIRMASS
OVERHEAD. WEAK UPPER RIDGING QUICKLY MOVES IN BEHIND THE
SHORTWAVE...EXTENDING FROM A RIDGE OVER THE WRN CONUS.
MODELS DO NOT SHOW ANY WAVES MOVING THROUGH ON TUE...BUT GIVEN NW
FLOW ALOFT IT IS HARD TO COMPLETELY RULE OUT AFTERNOON PRECIP...BUT
FOR NOW WILL LEAVE PRECIP OUT OF THE FORECAST. WITH ONLY SCATTERED
CU FOR CLOUDS...850MB TEMPS AOA 12MB SHOULD LEAD TO HIGH TEMPS IN
THE MID TO UPPER 70S...WITH A FEW LOW 80S POSSIBLE.
A WEAK SHORTWAVE TROUGH IS THEN SET TO MOVE NEAR THE CWA WED...ALSO
BRINGING A COLD FRONT INTO THE AREA. LIMITED MOISTURE AND
UNCERTAINTY REGARDING THE STRENGTH AND TRACK OF THE SHORTWAVE HAS
LEAD TO LIMITED CONFIDENCE WITH THIS SYSTEM...SO KEPT PRECIP CHANCES
ON THE LOW SIDE. HIGH TEMPS SHOULD BE SIMILAR TO TUE.
FOR WED NIGHT THROUGH NEXT SUN...MODELS SHOW THE COLD FRONT FROM WED/WED
NIGHT STALLING OVER OR NEAR THE CWA THU THROUGH FRI UNTIL AN
UPPER/SFC TROUGH MOVE THROUGH FRI NIGHT AND SAT. MODELS ALSO SHOW A
STRONGER UPPER LOW MOVING ACROSS SRN CANADA STARTING WED
NIGHT...THEN MOVING TO MANITOBA BY 00Z NEXT MON. WHEREAS THE 00Z/19
GFS AND 00Z/19 ECMWF AGREE PRETTY WELL ON THE LARGE SCALE
PATTERN...THE ECMWF HAS HAD VERY POOR RUN TO RUN CONTINUITY. THE GFS
ON THE OTHER HAND HAS SHOWN FAIRLY GOOD RUN TO RUN
CONTINUITY...LEADING TO MORE CONFIDENCE IN THE GFS SOLUTION BUT LOW
FORECAST CONFIDENCE OVERALL FOR THU ON. DID NOT SPEND TOO MUCH TIME
ON THIS PART OF THE FORECAST GIVEN LIMITED CONFIDENCE...AND SINCE
CONSENSUS OF MODEL DATA /WHICH FAVORS THE GFS/ LOOKED
REASONABLE...SO JUST USED THAT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 134 AM EDT MON AUG 20 2012
ALTHOUGH DISTURBANCES ROTATING AROUND A DEEP CLOSED LOW NEAR JAMES
BAY WILL BRING PERIODS OF CLOUDS TO UPPER MI DURING THE FCST
PERIOD...EXPECT VFR CONDITIONS TO PREVAIL WITH RELATIVELY DRY NEAR
SFC LAYER. ALTHOUGH THERE COULD BE SOME FOG MAINLY AT SAW/IWD
OVERNIGHT WITH LIGHT WINDS UNDER WEAK SFC HI PRES RIDGE...NO FOG WAS
OBSERVED UPSTREAM LAST NIGHT WITHIN THE DRY AIRMASS. SO KEPT A
MENTION OF FOG OUT OF TAFS AT THIS TIME.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 332 PM EDT SUN AUG 19 2012
EXPECT WINDS NO HIER THAN 20 KTS THRU THU WITH WEAK PRES GRADIENT
DOMINATING THE UPPER GREAT LAKES. SINCE HI PRES WILL DOMINATE MOST
OF THE TIME UNTIL LATER IN THE WEEK...THERE WILL BE LITTLE THREAT OF
PRECIPITATION UNTIL THU.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...JLB
MARINE...KC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
421 AM EDT MON AUG 20 2012
.SYNOPSIS...
A SLOW MOVING FRONT...IN COMBINATION WITH AN UPPER LEVEL
DISTURBANCE...WILL BRING THE CHANCE FOR SHOWERS AND ISOLATED
THUNDERSTORMS TO THE REGION TODAY. A STALLED FRONT TO OUR EAST AND
AN UPPER LEVEL DISTURBANCE COULD TRIGGER A FEW ISOLATED SHOWERS OR
EVEN THUNDERSTORMS TUESDAY AFTERNOON...ESPECIALLY IN NORTHEAST
PENNSYLVANIA. HIGH PRESSURE WILL BUILD INTO THE REGION FOR
WEDNESDAY AND WEDNESDAY NIGHT WITH FAIR WEATHER EXPECTED.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED AS OF 4 AM...MINOR CHANGES TO POPS AS CONVECTIVE ACTVTY HAS
RAPIDLY DIMINISHED IN WRN NY UPON REACHING C NY. I DON/T EXPECT
MUCH MORE ACTVY UNTIL LATER OVERNIGHT WHEN SOME ISLD SCVTY CUD
REACH NE PA. OTHERWISE NO MAJOR CHANGES FROM EARLIER UPDATE.
PREVIOUS DSCN BELOW...
RADAR SHOWS SCATTERED PATCHES OF SHOWERS AND ISOLATED
THUNDERSTORMS MOVING NORTHEAST FROM PA INTO SC NY EARLY THIS
MORNING. THIS ACVTY WAS BEING SUPPORTED BY A SMALL UPPER LEVEL
RIPPLE SEEN WELL IN THE WATER VAPOR SATELLITE IMAGERY. THIS UPPER
LEVEL FEATURE WAS MOVING NORTHEAST TWD PA AND NY FROM WEST
VIRGINIA AND SUPPORTED A WEAK SFC LO OVER SERN OH. THIS UPPER
LEVEL WAVE AND ASSCTD SFC FEATURE WILL CONTINUE TO MOVE NORTHEAST
EARLY THIS MORNING BEFORE GETTING CAUGHT UP IN AN UPPER LEVEL
CONFLUENCE ZONE THAT WAS HANGING TOUGH BETWEEN AND STATIONARY
UPPER LEVEL LOW OVER JAMES BAY CANADA AND THE EVER PRESENT
SUBTROPICAL UPPER LEVEL RIDGE COMMON THIS TIME OF YEAR WELL OFF
THE EAST COAST. THUS THE WAVE AND ASSCTD SFC FEATURE WILL SHEAR
OUT BTWN 6Z AND 12Z AND THE PRECIPITATION THAT IT WAS SUPPORTING
WILL WEAKEN AS IT MOVES FARTHER NORTH AND EAST. TRENDS ON RADAR
INDICATE THIS. WATER VAPOR IMAGERY SHOWS IT WELL.
THE ONLY MODEL THAT SEEMS TO HAVE SOMEWHAT OF A HANDLE ON THE QPF
WITH THIS WEAK SYSTEM IS THE GFS...KEEPING SOME LIGHT QPF ACROSS
MUCH OF CENTRAL NY UNTIL ARND 6Z BEFORE WEAKENING IT. THE NAM HAS
NO PRECIP...THE LATEST CONVECTION ALLOWING HI RES WRF ARW AND WRF
NMM DO NOT HAVE ANY PRECIP TONIGHT FOR OUR AREA. THE RAP IS DOING A
BETTER JOB BUT HAS TOO MUCH COVERAGE SIMILAR TO THE GFS BUT MORE
IN NRN PA WHEN MOST OF THE ACVTY IS IN THE WRN PART OF NY. MODEL
SOUNDINGS ALL SHOW SOME WEAK COOLING ALOFT WITH THIS WAVE INITIALLY
BTWN 600 AND 500 MB WHICH ON SOME MODEL SOUNDINGS IS STILL CAPPED
BUT ON THE GFS AND SREF SOUNDINGS ARE NOT. THE RUC ALSO ALLOWS FOR
SOME SMALL CAPE. SO IT IS A VERY MARGINAL SITUATION FOR PRECIP.
ALL MODELS TREND THIS ACVTY DOWN OVERNIGHT SO WILL GO ALONG WITH
THAT TREND USING CURRENT RADAR TRENDS WHICH IS AN IMPROVEMENT OVER
THE MODELS. THERE IS SOME ELEVATED CAPE SO MAYBE A RUMBLE OF
THUNDER...BUT NOTHING SIGNIFICANT OVERNIGHT.
FOR TODAY...ANOTHER SHORT WAVE MO/IL WILL ROUND THE BASE OF THE
UPPER LEVEL TROF OVER THE GREAT LAKES AND OH VLLY AND LIFT
NORTHEASTWARD TODAY. THIS FEATURE WILL SUPPORT LIFTG AND COOLING
AT MID-LEVELS COINCIDENT WITH THE DAYTIME HEATING SUPPORTG SCT
SHWRS AND TSRA FORMING DURG THE DAY INTO THE AFTERNOON. CAPES ON
ALL MODELS ARE MARGINAL RUNNING ONLY IN THE HUNDREDS...GENERALLY
LESS THAN 500 J/KG. THE SHEAR IS WEAK BELOW 6 KM WHICH IS WHERE
MOST OF THE CAPE IS...SO THE EFFECTIVE SHEAR IS WEAK. THERE IS
STRONGER SHEAR ALOFT FROM 6KM ON UP BUT DO NOT BELIEVE WITH SUCH
LOW CAPE VALUES THAT WE WILL SEE ANY SVR WEATHER. ANY STORM THAT
CAN REACH THESE HIGHER ALTITUDES LIKELY WILL GET SHEARED OUT
ANYWAY. SO JUST HAVE CHC POPS FOR LATER IN THE DAY INTO THE
AFTERNOON.
SHOWERS AND THUNDERSTORMS WILL WANE QUICKLY THIS EVENING AS THIS
NEXT SHORTWAVE SHEARS OUT IN THIS EVER PRESENT CONFLUENT ZONE
OVERHEAD TONIGHT. THIS OCCURS COINCIDENT WITH THE LOSS OF THE
DAY/S HEATING. FURTHERMORE WITH STRGR UPPER CONFLUENCE...A SFC
RIDGE WILL FORM OVER THE REGION...LEADING TO SOME POTENTIAL
CLEARING. WILL MONITOR FOR POTENTIAL VALLEY FOG LATE TONIGHT WITH
SHORT TERM UPDATE COMING SOON.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
TUESDAY WILL BEGIN WITH SCT-BKN MID-HI CLDS ARND AS A STRUNG OUT
FRONTL SYSTEM IS STALLED OFFSHORE WITH A DEPARTING SFC WAVE. THE
CMC AND NAM ARE STRONGEST WITH THE SFC WAVE DEVELOPMENT WITH THE
EURO AND GFS MUCH MORE WEAKER FLATTER WITH THE PRESSURE FIELD
OFFSHORE. THIS MAKES A DIFFERENCE FOR OUR AREA IN THAT THE NAM AND
CMC HAVE A STRONGER LL HIGH PRESSURE SYSTEM OVER OUR AREA TUESDAY
WHICH TENDS TO SUPRESS CONVECTIVE DEVELOPMENT. THE NAM MODEL
SOUNDINGS FOR TUESDAY DON/T PRODUCE ANY SIGNIFCANT CAPE AND APPEAR
CAPPED TO SOME EXTENT BY A MID-LVL INVERSION. THE EURO AND GFS
HAVE A WEAKER SFC PRESSURE RDG OVER OUR AREA WITH MORE LOW-LEVEL
MOISTURE HANGING ARND. THE GFS SOUNDINGS DO GENERATE CAPE WITH THE
AFTERNOON HEATING SUGGESTIVE OF ISLD TO SCT SHRA AND EVEN SOME
TSRA. LI/S ARE SLIGHTLY NEGATIVE ON THE GFS WITH CAPES IN THE
HUNDREDS AGAIN....MAINLY FROM THE SRN TIER INTO NRN PA. SO NOTHING
MAJOR. WIND SHEARS ARE WEAK AND CAPE IS NOT IMPRESSIVE SO WILL
HAVE ISLD TO SCT SHRA AND TSRA WITH HIGHEST POPS IN NE PA AND
LOWER POPS AS YOU TRAVEL N INTO NC NY WHERE CAPE IS MINIMAL.
FOR TUESDAY NIGHT...ALL CONVECTIVE ACVTY WINDS DOWN WITH LOSS OF
DAY/S HEATING. SFC HIGH PRESSURE DOMINATES ON ALL MODELS AND THERE
IS LARGE SCALE SUBSC. SO WILL WIND DOWN ANY RESIDUAL POPS FROM THE
EARLY EVENING.
FOR WEDNESDAY AND WEDNESDAY NIGHT...HIGH PRESSURE TAKES CONTROL WITH
LARGE SCALE SUBSC AND MORE STBL AIR IN PLACE. SO WED CUD BE THE
NICEST DAY OF THIS FORECAST PD.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
4 AM MON UPDATE... OVERALL...A QUIET PD STILL LOOKS TO BE IN THE
OFFING FOR NY/PA...AS THE LATEST EC/GFS AND ASSOCD ENSEMBLE MEANS
CONTINUE TO INDICATE THAT A FLAT UPR-LVL TROUGH AXIS ACRS THE ERN
CONUS WILL FURTHER DE-AMPLIFY WITH TIME. IN FACT...THE LATEST
RUNS NOW ACTUALLY INDICATE A NARROW RIDGE AXIS DEVELOPING BY LATER
NEXT WEEKEND.
AT THE SFC...THE MAIN BAROCLINIC ZNS/FRNTS MOSTLY STAY SITUATED
WELL TO OUR S THROUGH THE SRN MID-ATL...AND ALSO UPSTREAM THROUGH
SRN CANADA AND THE NRN LKS RGN. TWDS NEXT SUN/MON...THE LATTER
SYSTEM MAY TRY TO EDGE CLOSE ENOUGH TO BRING ISOLD DIURNALLY DRIVEN
CONVECTION. FOR NOW...THE SCHC POPS WE HAVE IN THERE WILL SUFFICE.
TEMPS SHOULD UNDERGO A GRADUAL WARMING TREND UNDER RISING HGTS
ALOFT...WITH DAILY HIGHS MAINLY IN THE 80S BY NEXT WEEKEND.
PREV DISC... SUBTLE FEATURES WILL INFLUENCE THE WX IN THE LONG
TERM AS THE SFC RDGG BRKS DOWN EARLY IN THE PD. OPERATIONAL MODELS
SHOW A WEAK FNTL BNDRY TRYING TO DROP SOUTH FROM CANADA FRI INTO
SAT BEFORE EVENTUALLY WASHING OUT OVER THE AREA. WITH HTG...THIS
MAY BE ENUF LL CONV TO DVLP ISLTD AFTN CONV FRI AND SAT.
TEMPS WILL SHOW A GRADUAL RECOVERY THRU THE PD...RCHG ABV NRML BY
FRI AND SAT. STILL DFRNCS BETWEEN HPC GUID AND GFS GENERATED
MEX...SO BLENDED GUID WITH PRVS FCST TO CONT A SLOW UPWARD TREND.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
06Z MON UPDATE... FOR THE CNY TERMINALS...VFR SHOULD BE THE
PREVAILING CONDITION THIS VALID TAF PD (THROUGH 06Z TUE). THE MOST
PROBABLE TIME FRAME FOR -SHRA WILL BE LATE MRNG INTO THE AFTN
(ROUGHLY 14-19Z)...WITH UNRESTRICTED CONDS FOR THE MOST PART.
KBGM/KITH (ON THE HILLTOPS) MAY SEE PERIODIC MVFR.
AT KAVP...-SHRA ARE EXPECTED TO BE THE MOST PERSISTENT LATER
TDY...WITH THE BEST SHOT AT PROLONGED MVFR RESTRICTIONS.
BY LATE AFTN/EARLY EVE...A WEAK COLD FRNT WILL LIKELY HAVE PUSHED
THROUGH THE FA...WITH SOMEWHAT DRIER INCOMING FROM THE W.
SRLY COMPONENT SFC WINDS 5-10 KT...WILL SHIFT INTO THE W LATE IN
THE DAY...BEFORE TURNING LGT AND VRBL AFTER 00Z TUE.
OUTLOOK...
TUE...MOSTLY VFR...WITH BRIEF RESTRICTIONS PSBL IN THE AFTN FROM
ISOLD SHRA/TSRA.
WED/THU/FRI...MAINLY VFR. MRNG VLY FOG PSBL WITH IFR AT KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...DJN
LONG TERM...DGM/MLJ
AVIATION...MLJ/RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
358 AM EDT MON AUG 20 2012
.SYNOPSIS...
A SLOW MOVING FRONT...IN COMBINATION WITH AN UPPER LEVEL
DISTURBANCE...WILL BRING THE CHANCE FOR SHOWERS AND ISOLATED
THUNDERSTORMS TO THE REGION TODAY. HIGH PRESSURE WILL BUILD INTO
THE REGION STARTING ON TUESDAY WITH FAIR WEATHER EXPECTED FOR MID
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
RADAR SHOWS SCATTERED PATCHES OF SHOWERS AND ISOLATED
THUNDERSTORMS MOVING NORTHEAST FROM PA INTO SC NY EARLY THIS
MORNING. THIS ACVTY WAS BEING SUPPORTED BY A SMALL UPPER LEVEL
RIPPLE SEEN WELL IN THE WATER VAPOR SATELLITE IMAGERY. THIS UPPER
LEVEL FEATURE WAS MOVING NORTHEAST TWD PA AND NY FROM WEST
VIRGINIA AND SUPPORTED A WEAK SFC LO OVER SERN OH. THIS UPPER
LEVEL WAVE AND ASSCTD SFC FEATURE WILL CONTINUE TO MOVE NORTHEAST
EARLY THIS MORNING BEFORE GETTING CAUGHT UP IN AN UPPER LEVEL
CONFLUENCE ZONE THAT WAS HANGING TOUGH BETWEEN AND STATIONARY
UPPER LEVEL LOW OVER JAMES BAY CANADA AND THE EVER PRESENT
SUBTROPICAL UPPER LEVEL RIDGE COMMON THIS TIME OF YEAR WELL OFF
THE EAST COAST. THUS THE WAVE AND ASSCTD SFC FEATURE WILL SHEAR
OUT BTWN 6Z AND 12Z AND THE PRECIPITATION THAT IT WAS SUPPORTING
WILL WEAKEN AS IT MOVES FARTHER NORTH AND EAST. TRENDS ON RADAR
INDICATE THIS. WATER VAPOR IMAGERY SHOWS IT WELL.
THE ONLY MODEL THAT SEEMS TO HAVE SOMEWHAT OF A HANDLE ON THE QPF
WITH THIS WEAK SYSTEM IS THE GFS...KEEPING SOME LIGHT QPF ACROSS
MUCH OF CENTRAL NY UNTIL ARND 6Z BEFORE WEAKENING IT. THE NAM HAS
NO PRECIP...THE LATEST CONVECTION ALLOWING HI RES WRF ARW AND WRF
NMM DO NOT HAVE ANY PRECIP TONIGHT FOR OUR AREA. THE RAP IS DOING A
BETTER JOB BUT HAS TOO MUCH COVERAGE SIMILAR TO THE GFS BUT MORE
IN NRN PA WHEN MOST OF THE ACVTY IS IN THE WRN PART OF NY. MODEL
SOUNDINGS ALL SHOW SOME WEAK COOLING ALOFT WITH THIS WAVE INITIALLY
BTWN 600 AND 500 MB WHICH ON SOME MODEL SOUNDINGS IS STILL CAPPED
BUT ON THE GFS AND SREF SOUNDINGS ARE NOT. THE RUC ALSO ALLOWS FOR
SOME SMALL CAPE. SO IT IS A VERY MARGINAL SITUATION FOR PRECIP.
ALL MODELS TREND THIS ACVTY DOWN OVERNIGHT SO WILL GO ALONG WITH
THAT TREND USING CURRENT RADAR TRENDS WHICH IS AN IMPROVEMENT OVER
THE MODELS. THERE IS SOME ELEVATED CAPE SO MAYBE A RUMBLE OF
THUNDER...BUT NOTHING SIGNIFICANT OVERNIGHT.
FOR TODAY...ANOTHER SHORT WAVE MO/IL WILL ROUND THE BASE OF THE
UPPER LEVEL TROF OVER THE GREAT LAKES AND OH VLLY AND LIFT
NORTHEASTWARD TODAY. THIS FEATURE WILL SUPPORT LIFTG AND COOLING
AT MID-LEVELS COINCIDENT WITH THE DAYTIME HEATING SUPPORTG SCT
SHWRS AND TSRA FORMING DURG THE DAY INTO THE AFTERNOON. CAPES ON
ALL MODELS ARE MARGINAL RUNNING ONLY IN THE HUNDREDS...GENERALLY
LESS THAN 500 J/KG. THE SHEAR IS WEAK BELOW 6 KM WHICH IS WHERE
MOST OF THE CAPE IS...SO THE EFFECTIVE SHEAR IS WEAK. THERE IS
STRONGER SHEAR ALOFT FROM 6KM ON UP BUT DO NOT BELIEVE WITH SUCH
LOW CAPE VALUES THAT WE WILL SEE ANY SVR WEATHER. ANY STORM THAT
CAN REACH THESE HIGHER ALTITUDES LIKELY WILL GET SHEARED OUT
ANYWAY. SO JUST HAVE CHC POPS FOR LATER IN THE DAY INTO THE
AFTERNOON.
SHOWERS AND THUNDERSTORMS WILL WANE QUICKLY THIS EVENING AS THIS
NEXT SHORTWAVE SHEARS OUT IN THIS EVER PRESENT CONFLUENT ZONE
OVERHEAD TONIGHT. THIS OCCURS COINCIDENT WITH THE LOSS OF THE
DAY/S HEATING. FURTHERMORE WITH STRGR UPPER CONFLUENCE...A SFC
RIDGE WILL FORM OVER THE REGION...LEADING TO SOME POTENTIAL
CLEARING. WILL MONITOR FOR POTENTIAL VALLEY FOG LATE TONIGHT WITH
SHORT TERM UPDATE COMING SOON.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
SHRA ARE XPCTD TO DIMINISH/MOV OUT ON MON EVNG. MDLS SUGGEST
POTNL FOR ISOLD ACTIVITY FAR SRN TIER AND NE PA ON TUE AND PSBLY WED.
OVERALL THE PTRN DOES NOT LOOK AS FVRBL FOR DIURNAL CONVECTIVE
DVLPMNT AS SFC HI PRES WILL BE BUILDING INTO THE RGN...AND
INSPECTION OF 12Z NAM/GFS PROFILES SHOWS VERY LIMITED CAPE SO
WILL LOWER POPS TO SLGT CHC THESE AREAS FOR TUE/WED AFTN. OTRW...NICE
WX WITH SEASONABLE TEMPS AND PS DAYS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
4 AM MON UPDATE... OVERALL...A QUIET PD STILL LOOKS TO BE IN THE
OFFING FOR NY/PA...AS THE LATEST EC/GFS AND ASSOCD ENSEMBLE MEANS
CONTINUE TO INDICATE THAT A FLAT UPR-LVL TROUGH AXIS ACRS THE ERN
CONUS WILL FURTHER DE-AMPLIFY WITH TIME. IN FACT...THE LATEST
RUNS NOW ACTUALLY INDICATE A NARROW RIDGE AXIS DEVELOPING BY LATER
NEXT WEEKEND.
AT THE SFC...THE MAIN BAROCLINIC ZNS/FRNTS MOSTLY STAY SITUATED
WELL TO OUR S THROUGH THE SRN MID-ATL...AND ALSO UPSTREAM THROUGH
SRN CANADA AND THE NRN LKS RGN. TWDS NEXT SUN/MON...THE LATTER
SYSTEM MAY TRY TO EDGE CLOSE ENOUGH TO BRING ISOLD DIURNALLY DRIVEN
CONVECTION. FOR NOW...THE SCHC POPS WE HAVE IN THERE WILL SUFFICE.
TEMPS SHOULD UNDERGO A GRADUAL WARMING TREND UNDER RISING HGTS
ALOFT...WITH DAILY HIGHS MAINLY IN THE 80S BY NEXT WEEKEND.
PREV DISC... SUBTLE FEATURES WILL INFLUENCE THE WX IN THE LONG
TERM AS THE SFC RDGG BRKS DOWN EARLY IN THE PD. OPERATIONAL MODELS
SHOW A WEAK FNTL BNDRY TRYING TO DROP SOUTH FROM CANADA FRI INTO
SAT BEFORE EVENTUALLY WASHING OUT OVER THE AREA. WITH HTG...THIS
MAY BE ENUF LL CONV TO DVLP ISLTD AFTN CONV FRI AND SAT.
TEMPS WILL SHOW A GRADUAL RECOVERY THRU THE PD...RCHG ABV NRML BY
FRI AND SAT. STILL DFRNCS BETWEEN HPC GUID AND GFS GENERATED
MEX...SO BLENDED GUID WITH PRVS FCST TO CONT A SLOW UPWARD TREND.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
06Z MON UPDATE... FOR THE CNY TERMINALS...VFR SHOULD BE THE
PREVAILING CONDITION THIS VALID TAF PD (THROUGH 06Z TUE). THE MOST
PROBABLE TIME FRAME FOR -SHRA WILL BE LATE MRNG INTO THE AFTN
(ROUGHLY 14-19Z)...WITH UNRESTRICTED CONDS FOR THE MOST PART.
KBGM/KITH (ON THE HILLTOPS) MAY SEE PERIODIC MVFR.
AT KAVP...-SHRA ARE EXPECTED TO BE THE MOST PERSISTENT LATER
TDY...WITH THE BEST SHOT AT PROLONGED MVFR RESTRICTIONS.
BY LATE AFTN/EARLY EVE...A WEAK COLD FRNT WILL LIKELY HAVE PUSHED
THROUGH THE FA...WITH SOMEWHAT DRIER INCOMING FROM THE W.
SRLY COMPONENT SFC WINDS 5-10 KT...WILL SHIFT INTO THE W LATE IN
THE DAY...BEFORE TURNING LGT AND VRBL AFTER 00Z TUE.
OUTLOOK...
TUE...MOSTLY VFR...WITH BRIEF RESTRICTIONS PSBL IN THE AFTN FROM
ISOLD SHRA/TSRA.
WED/THU/FRI...MAINLY VFR. MRNG VLY FOG PSBL WITH IFR AT KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...
LONG TERM...DGM/MLJ
AVIATION...MLJ/RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
247 AM EDT MON AUG 20 2012
.SYNOPSIS...
A SLOW MOVING FRONT...IN COMBINATION WITH AN UPPER LEVEL
DISTURBANCE...WILL BRING THE CHANCE FOR SHOWERS AND ISOLATED
THUNDERSTORMS TO THE REGION TODAY. HIGH PRESSURE WILL BUILD INTO
THE REGION STARTING ON TUESDAY WITH FAIR WEATHER EXPECTED FOR MID
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
RADAR SHOWS SCATTERED PATCHES OF SHOWERS AND ISOLATED
THUNDERSTORMS MOVING NORTHEAST FROM PA INTO SC NY EARLY THIS
MORNING. THIS ACVTY WAS BEING SUPPORTED BY A SMALL UPPER LEVEL
RIPPLE SEEN WELL IN THE WATER VAPOR SATELLITE IMAGERY. THIS UPPER
LEVEL FEATURE WAS MOVING NORTHEAST TWD PA AND NY FROM WEST
VIRGINIA AND SUPPORTED A WEAK SFC LO OVER SERN OH. THIS UPPER
LEVEL WAVE AND ASSCTD SFC FEATURE WILL CONTINUE TO MOVE NORTHEAST
EARLY THIS MORNING BEFORE GETTING CAUGHT UP IN AN UPPER LEVEL
CONFLUENCE ZONE THAT WAS HANGING TOUGH BETWEEN AND STATIONARY
UPPER LEVEL LOW OVER JAMES BAY CANADA AND THE EVER PRESENT
SUBTROPICAL UPPER LEVEL RIDGE COMMON THIS TIME OF YEAR WELL OFF
THE EAST COAST. THUS THE WAVE AND ASSCTD SFC FEATURE WILL SHEAR
OUT BTWN 6Z AND 12Z AND THE PRECIPITATION THAT IT WAS SUPPORTING
WILL WEAKEN AS IT MOVES FARTHER NORTH AND EAST. TRENDS ON RADAR
INDICATE THIS. WATER VAPOR IMAGERY SHOWS IT WELL.
THE ONLY MODEL THAT SEEMS TO HAVE SOMEWHAT OF A HANDLE ON THE QPF
WITH THIS WEAK SYSTEM IS THE GFS...KEEPING SOME LIGHT QPF ACROSS
MUCH OF CENTRAL NY UNTIL ARND 6Z BEFORE WEAKENING IT. THE NAM HAS
NO PRECIP...THE LATEST CONVECTION ALLOWING HI RES WRF ARW AND WRF
NMM DO NOT HAVE ANY PRECIP TONIGHT FOR OUR AREA. THE RAP IS DOING A
BETTER JOB BUT HAS TOO MUCH COVERAGE SIMILAR TO THE GFS BUT MORE
IN NRN PA WHEN MOST OF THE ACVTY IS IN THE WRN PART OF NY. MODEL
SOUNDINGS ALL SHOW SOME WEAK COOLING ALOFT WITH THIS WAVE INITALLY
BTWN 600 AND 500 MB WHICH ON SOME MODEL SOUNDINGS IS STILL CAPPED
BUT ON THE GFS AND SREF SOUNDINGS ARE NOT. THE RUC ALSO ALLOWS FOR
SOME SMALL CAPE. SO IT IS A VERY MARGINAL SITUATION FOR PRECIP.
ALL MODELS TREND THIS ACVTY DOWN OVERNIGHT SO WILL GO ALONG WITH
THAT TREND USING CURRENT RADAR TRENDS WHICH IS AN IMPROVEMENT OVER
THE MODELS. THERE IS SOME ELEVATED CAPE SO MAYBE A RUMBLE OF
THUNDER...BUT NOTHING SIGNIFICANT OVERNIGHT.
FOR TODAY...ANOTHER SHORT WAVE MO/IL WILL ROUND THE BASE OF THE
UPPER LEVEL TROF OVER THE GREAT LAKES AND OH VLLY AND LIFT
NORTHEASTWARD TODAY. THIS FEATURE WILL SUPPORT LIFTG AND COOLING
AT MID-LEVELS COINICENT WITH THE DAYTIME HEATING SUPPORTG SCT
SHWRS AND TSRA FORMING DURG THE DAY INTO THE AFTERNOON. CAPES ON
ALL MODELS ARE MARGINAL RUNNING ONLY IN THE HUNDREDS...GENERALLY
LESS THAN 500 J/KG. THE SHEAR IS WEAK BELOW 6 KM WHICH IS WHERE
MOST OF THE CAPE IS...SO THE EFFECTIVE SHEAR IS WEAK. THERE IS
STRONGER SHEAR ALOFT FROM 6KM ON UP BUT DO NOT BELIEVE WITH SUCH
LOW CAPE VALUES THAT WE WILL SEE ANY SVR WEATHER. ANY STORM THAT
CAN REACH THESE HIGHER ALTITUDES LIKELY WILL GET SHEARED OUT
ANYWAY. SO JUST HAVE CHC POPS FOR LATER IN THE DAY INTO THE
AFTERNOON.
SHOWERS AND THUNDERSTORMS WILL WANE QUICKLY THIS EVENING AS THIS
NEXT SHORTWAVE SHEARS OUT IN THIS EVER PRESENT CONFLUENT ZONE
OVERHEAD TONIGHT. THIS OCCURS COINCIDENT WITH THE LOSS OF THE
DAY/S HEATING. FURTHERMORE WITH STRGR UPPER CONFLUENCE...A SFC
RIDGE WILL FORM OVER THE REGION...LEADING TO SOME POTENTIAL
CLEARING. WILL MONITOR FOR POTENTIAL VALLEY FOG LATE TONIGHT WITH
SHORT TERM UPDATE COMING SOON.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
SHRA ARE XPCTD TO DIMINISH/MOV OUT ON MON EVNG. MDLS SUGGEST
POTNL FOR ISOLD ACTIVITY FAR SRN TIER AND NE PA ON TUE AND PSBLY WED.
OVERALL THE PTRN DOES NOT LOOK AS FVRBL FOR DIURNAL CONVECTIVE
DVLPMNT AS SFC HI PRES WILL BE BUILDING INTO THE RGN...AND
INSPECTION OF 12Z NAM/GFS PROFILES SHOWS VERY LIMITED CAPE SO
WILL LOWER POPS TO SLGT CHC THESE AREAS FOR TUE/WED AFTN. OTRW...NICE
WX WITH SEASONABLE TEMPS AND PS DAYS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
SUBTLE FEATURES WILL INFLUENCE THE WX IN THE LONG TERM AS THE SFC
RDGG BRKS DOWN EARLY IN THE PD. OPERATIONAL MODELS SHOW A WEAK FNTL
BNDRY TRYING TO DROP SOUTH FROM CANADA FRI INTO SAT BEFORE
EVENTUALLY WASHING OUT OVER THE AREA. WITH HTG...THIS MAY BE ENUF
LL CONV TO DVLP ISLTD AFTN CONV FRI AND SAT.
TEMPS WILL SHOW A GRADUAL RECOVERY THRU THE PD...RCHG ABV NRML BY
FRI AND SAT. STILL DFRNCS BETWEEN HPC GUID AND GFS GENERATED
MEX...SO BLENDED GUID WITH PRVS FCST TO CONT A SLOW UPWARD TREND.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
06Z MON UPDATE... FOR THE CNY TERMINALS...VFR SHOULD BE THE
PREVAILING CONDITION THIS VALID TAF PD (THROUGH 06Z TUE). THE MOST
PROBABLE TIME FRAME FOR -SHRA WILL BE LATE MRNG INTO THE AFTN
(ROUGHLY 14-19Z)...WITH UNRESTRICTED CONDS FOR THE MOST PART.
KBGM/KITH (ON THE HILLTOPS) MAY SEE PERIODIC MVFR.
AT KAVP...-SHRA ARE EXPECTED TO BE THE MOST PERSISTENT LATER
TDY...WITH THE BEST SHOT AT PROLONGED MVFR RESTRICTIONS.
BY LATE AFTN/EARLY EVE...A WEAK COLD FRNT WILL LIKELY HAVE PUSHED
THROUGH THE FA...WITH SOMEWHAT DRIER INCOMING FROM THE W.
SRLY COMPONENT SFC WINDS 5-10 KT...WILL SHIFT INTO THE W LATE IN
THE DAY...BEFORE TURNING LGT AND VRBL AFTER 00Z TUE.
OUTLOOK...
TUE...MOSTLY VFR...WITH BRIEF RESTRICTIONS PSBL IN THE AFTN FROM
ISOLD SHRA/TSRA.
WED/THU/FRI...MAINLY VFR. MRNG VLY FOG PSBL WITH IFR AT KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...
LONG TERM...DGM
AVIATION...MLJ/RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
202 AM EDT MON AUG 20 2012
.SYNOPSIS...
A SLOW MOVING FRONT...IN COMBINATION WITH AN UPPER LEVEL
DISTURBANCE...WILL BRING THE CHANCE FOR SHOWERS AND ISOLATED
THUNDERSTORMS TO THE REGION LATER TONIGHT INTO MONDAY EVENING. HIGH
PRESSURE WILL BUILD INTO THE REGION STARTING ON TUESDAY WITH FAIR
WEATHER EXPECTED FOR MID WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
10 PM UPDATE...
A THIN LINE OF RAIN...WITH SOME THUNDER...HAS DEVELOPED OVER
WESTERN NY AS PREDICTED BY THE HRRR AND LOCAL HIGHER RESOLUTION
MODELS...BUT IT IS NOT AS EXPANSIVE AS THE EARLIER RUNS OF THE
MODELS HAD INDICATED. WITH THAT SAID LIKELY POPS OVER THE NEXT
HOUR OR TWO ACROSS STEUBEN COUNTY NEAR HORNELL AND CHANCE POPS
THROUGH MIDNIGHT OVER THE FINGER LAKES WERE THE MAIN UPDATE TO
MAKE GIVEN WE NOW HAVE ACTION ON THE RADAR. USING THE HRRR AS A
GUIDE...STILL EXPECTING CONVECTION TO PROGRESS EAST AND DISSIPATE
QUICKLY SO BLENDING WITH THE PREVIOUS FORECAST OF SLIGHT CHANCE
POPS OVERNIGHT LOOKS GOOD...ESPECIALLY INTO THE SOUTHERN TIER OF
NY AND NEPA.
7 PM UPDATE...
BASED ON VERY LITTLE RADAR RETURNS AT THE MOMENT...WILL TRIM BACK
POPS THROUGH MIDNIGHT TO SLIGHT CHANCE RANGE. THE HIGHER
RESOLUTION MODELS SUCH AS THE HRRR CONTINUE TO SUGGEST SOME
DEVELOPMENT OF SHOWERS BY 0Z OVER WESTERN NY AND GRADUALLY MOVE
THIS EAST THROUGH 06Z. THE LATEST VIS SATELLITE LOOP DOES SHOW
SOME CLOUDS IN THIS AREA BUT IT SEEMS MOVE LIKELY THAT IF WE SEE
ANYTHING OVERNIGHT...IT WILL BE THANKS TO AN INVERTED TROF OVER
WESTERN PA GRADUALLY MOVING EAST. WITH THAT IN MIND CONTAINED
SLIGHT CHANCE POPS TO EXTEND FROM THE FINGER LAKES (0Z - 4Z) SOUTHEAST
THROUGH THE SOUTHERN TIER OF NY (05Z-10Z) INTO NEPA (06Z-11Z). TO
BLEND BETTER WITH TOMORROW`S FORECAST I SHOW A LULL EARLY IN THE
DAY WITH A TRANSITION TO INCREASING POPS...AS THIS STILL APPEARS
LIKELY WITH THE COMBINATION OF DIURNAL HEATING AND A FRONT MOVING
INTO THE AREA. WITH A GENERAL INCREASE IN MID LEVEL CLOUDS
TONIGHT...WIDESPREAD VALLEY FOG IS NOT EXPECTED. THE PREVIOUS AFD IS
BELOW...
SFC ANYLS SHOWS A CDFNT ACRS LOWER ONTARIO INTO CNTRL MI WITH
AN INVERTED TROF DVLPNG OVER ERN OH/WRN PA. AT UPR LVLS...THE DEEP
TROF OVER THE ERN U.S. WILL GRADUALLY LIFT NEWD/PULL OUT...WITH
MDLS SUGGESTING THE CDFNT/INVERTED TROF WILL EVENTUALLY MERGE AND
WORK EWD ACRS THE BGM FCST AREA ON MON...AS LOW PRES TRACKS NEWD
OFF THE MID ATLC CST. THE MAIN TROF AXIS WON`T PASS THE FCST AREA
TIL WED....WITH UPR FLOW BCMG GNRLY ZONAL BY WED EVNG.
GRADUAL MOISTENING WILL OCCUR OVRNGT AS SRLY FLOW DVLPS AHEAD OF THE
SFC TROF/FNT. SHORT RNG MESO MDLS INCLUDING THE RUC AND LCL WRF SUGGEST
THAT ACTIVITY ACRS CNTRL PA COULD TRACK NWD INTO THE CNTRL SRN
TIER THIS EVNG ALONG AND EAST OF THE SFC TROF...AND HINTS THAT
ADDNL ISOLD/WDLY SCT DVLPMNT IS PSBL...SO WE INDICATE LOW CHC POPS
SPREADING N AND NE ACRS THE FCST AREA OVRNGT.
ANOTHER S/WV IS FCST TO APRCH THE RGN TMRW AFTN...AND THIS IN
COMBINATION WITH THE SFC BNDRY SHUD HELP TO FOCUS ACTIVITY ACRS
CNTRL/ERN ZONES ON MON AFTN. CHCS FOR TSRA WILL BE ON THE LOW SIDE
GIVEN LIMITED INSTABILITY. TEMPS COULD BE TRICKY ON MON...FOR NOW
INDICATED COOLEST MAXES ACRS SE ZONES (A70 OR L70S).
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
SHRA ARE XPCTD TO DIMINISH/MOV OUT ON MON EVNG. MDLS SUGGEST
POTNL FOR ISOLD ACTIVITY FAR SRN TIER AND NE PA ON TUE AND PSBLY WED.
OVERALL THE PTRN DOES NOT LOOK AS FVRBL FOR DIURNAL CONVECTIVE
DVLPMNT AS SFC HI PRES WILL BE BUILDING INTO THE RGN...AND
INSPECTION OF 12Z NAM/GFS PROFILES SHOWS VERY LIMITED CAPE SO
WILL LOWER POPS TO SLGT CHC THESE AREAS FOR TUE/WED AFTN. OTRW...NICE
WX WITH SEASONABLE TEMPS AND PS DAYS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
SUBTLE FEATURES WILL INFLUENCE THE WX IN THE LONG TERM AS THE SFC
RDGG BRKS DOWN EARLY IN THE PD. OPERATIONAL MODELS SHOW A WEAK FNTL
BNDRY TRYING TO DROP SOUTH FROM CANADA FRI INTO SAT BEFORE
EVENTUALLY WASHING OUT OVER THE AREA. WITH HTG...THIS MAY BE ENUF
LL CONV TO DVLP ISLTD AFTN CONV FRI AND SAT.
TEMPS WILL SHOW A GRADUAL RECOVERY THRU THE PD...RCHG ABV NRML BY
FRI AND SAT. STILL DFRNCS BETWEEN HPC GUID AND GFS GENERATED
MEX...SO BLENDED GUID WITH PRVS FCST TO CONT A SLOW UPWARD TREND.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
06Z MON UPDATE... FOR THE CNY TERMINALS...VFR SHOULD BE THE
PREVAILING CONDITION THIS VALID TAF PD (THROUGH 06Z TUE). THE MOST
PROBABLE TIME FRAME FOR -SHRA WILL BE LATE MRNG INTO THE AFTN
(ROUGHLY 14-19Z)...WITH UNRESTRICTED CONDS FOR THE MOST PART.
KBGM/KITH (ON THE HILLTOPS) MAY SEE PERIODIC MVFR.
AT KAVP...-SHRA ARE EXPECTED TO BE THE MOST PERSISTENT LATER
TDY...WITH THE BEST SHOT AT PROLONGED MVFR RESTRICTIONS.
BY LATE AFTN/EARLY EVE...A WEAK COLD FRNT WILL LIKELY HAVE PUSHED
THROUGH THE FA...WITH SOMEWHAT DRIER INCOMING FROM THE W.
SRLY COMPONENT SFC WINDS 5-10 KT...WILL SHIFT INTO THE W LATE IN
THE DAY...BEFORE TURNING LGT AND VRBL AFTER 00Z TUE.
OUTLOOK...
TUE...MOSTLY VFR...WITH BRIEF RESTRICTIONS PSBL IN THE AFTN FROM
ISOLD SHRA/TSRA.
WED/THU/FRI...MAINLY VFR. MRNG VLY FOG PSBL WITH IFR AT KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...HEDEN
SHORT TERM...
LONG TERM...DGM
AVIATION...MLJ/RRM
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
149 AM EDT MON AUG 20 2012
.SYNOPSIS...
AN UNSETTLED WEATHER PATTERN WILL PERSIST THROUGH MID WEEK...AS THE
FRONT REMAINS STALLED OVER THE CAROLINAS. A DRYING TREND IS EXPECTED
LATE IN THE WEEK AS HIGH PRESSURE BUILDS FROM THE WEST AND PUSHES
THE FRONT OUT TO SEA.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 830 PM SUNDAY...ONLY ISOLATED CONVECTION CONTINUES MAINLY
SOUTHWEST OF THE COUNTY WARNING AREA. THE LATEST HRRR INDICATES
THAT CONVECTION MAY DEVELOP OVERNIGHT TO THE SOUTHWEST AND SPREADING
NORTHWEST INTO OUR AREA LATER THIS EVENING. AT THIS TIME WILL
CONTINUE WITH THE SCATTERED TO ISOLATED CONVECTION OVERNIGHT.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...THE AXIS OF THE UPPER LEVEL TROUGH WILL
REMAIN TO THE WEST AND WEAK IMPULSES WILL ROTATE AROUND THIS
FEATURE. THE PRECIPITABLE WATER WILL REMAIN AT OR ABOVE 2 INCHES
THROUGH TUESDAY MORNING WITH A SLOW DRYING TREND TOWARDS THE END.
SPC DOES MENTION MARGINAL DAMAGING WIND POTENTIAL ON TUESDAY.
WITH THE INSTABILITY AND MOISTURE WILL INCLUDE A HIGH CHANCE OF
CONVECTION EACH DAY.
MAXIMUM TEMPERATURES ARE EXPECTED TO REACH THE MID 80S EACH DAY
AND MINIMUM TEMPERATURES AROUND 70S MONDAY AND UPPER 60S TUESDAY
NIGHT AS COOLER HIGH PRESSURE PUSHES THE WARMER AND MOIST AIR TO
THE SOUTH AND EAST.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 3 PM SUNDAY...HIGH PRESSURE WILL BUILD INTO THE REGION AND
PUSH THE STATIONARY FRONT ALONG THE COAST OUT TO SEA. THIS WILL
ALLOW FOR DRIER AND COOLER AIR. THE WILL BE A CHANCE OF CONVECTION
EARLY WEDNESDAY AND AS WE PROGRESS INTO THE WEEKEND ONLY AN
ISOLATED THUNDERSTORM IS EXPECTED. MAXIMUM TEMPERATURE ARE
EXPECTED TO BE IN THE MID 80S DURING THE DAY AND MINIMUM
TEMPERATURES WILL BE DROP FROM THE UPPER 60S ON WEDNESDAY TO THE
MID 60S BY THE WEEKEND.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...AREAS OF MVFR/IFR CEILINGS AND MVFR VISIBILITIES IN
ASSOCIATION WITH SHOWERS AND THUNDERSTORMS INTO MID MORNING.
CONDITIONS MAY IMPROVE TO VFR THIS AFTERNOON...THOUGH VCSH
AND VCTS ARE EXPECTED THROUGHOUT THE DAY.
MODELS AND CURRENT TRENDS INDICATE CONVECTION WILL BE ON THE
INCREASE THROUGH SUNRISE AND WITH THAT HAVE INCLUDED TEMPO IFR
CEILINGS AND MVFR VISIBILITIES INTO THIS MORNING.
FOR THE REMAINDER OF THE PERIOD...CANNOT RULE OUT ISOLATED TO
SCATTERED TSRA...THUS HAVE INTRODUCED VCTS INTO CURRENT FCST.
WEST-SOUTHWEST WINDS WILL CONTINUE THROUGH THE DAY WITH SUSTAINED
SPEEDS AOB 10 KTS.
EXTENDED OUTLOOK...SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITH
TEMPO MVFR/IFR THROUGH TUESDAY. ISOLATED SHOWERS AND THUNDERSTORMS
WEDNESDAY THROUGH FRIDAY.
&&
.MARINE...
NEAR TERM /THROUGH 6 AM MONDAY/...
AS OF 830 PM SUNDAY...SOUTHWEST WINDS OF 10 KNOTS ARE CONTINUING
OVER THE WATERS AS A WEAK FRONTAL BOUNDARY WAVERS BACK AND FORTH
INLAND OVERNIGHT. SEAS WILL RANGE FROM 2 TO 4 FEET. HRRR MODEL IS
HINTING OF CONVECTION DEVELOPING TO THE SOUTHWEST OF THE COASTAL
WATERS AND MOVING ACROSS OVERNIGHT. CONFIDENCE IS LOW SO WILL LEAVE
CHANCE OF THUNDERSTORMS IN FOR OVERNIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...WITH FRONTAL BOUNDARY SLOWLY MOVING TO THE WATERS
BY THE END OF THE PERIOD...WIND SPEEDS ARE EXPECTED TO BE AROUND
10 TO 15 KNOTS AND SEAS RANGING BETWEEN 2 TO 4 FEET. AS
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 3 PM SUNDAY...AS THE FRONTAL BOUNDARY LINGERS AT THE COAST
THE COASTAL WATER WINDS WILL BE AROUND 10 T0 15 KNOTS AND AS HIGH
PRESSURE BUILDS OVER THE WATERS BY THURSDAY WINDS WILL BE LIGHT
FROM THE NORTH TO NORTHWEST. SEAS OF 3 FT OR LESS ARE EXPECTED
THROUGH THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HAWKINS
SHORT TERM...HAWKINS
LONG TERM...HAWKINS
AVIATION...RJD/SGL
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
340 AM EDT MON AUG 20 2012
.SYNOPSIS...
A SERIES OF DISTURBANCES ALOFT PASSING INTO TUESDAY. WEAK HIGH
PRESSURE FOR WEDNESDAY THROUGH THE END OF THE WORK WEEK PROVIDES
GRADUAL WARMING TREND.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE PARADE OF MID LEVEL/UPPER LEVEL DISTURBANCES JUST KEEPS MARCHING
ON. ONE STRETCHED OUT VORT MAX AT 500 MB STILL DEPICTED BY RAP FM
NR MGW TO N OF CRW BY DAWN THIS MORNING. WILL HOLD ONTO SOME SLIGHT
CHANCE POPS ACROSS NORTH CENTRAL WV INTO THE CENTRAL MOUNTAINS.
OTHERWISE...MORE TYPICAL AUGUST FOG OR LOW STRATUS CLOUDS WILL GREET
THE MONDAY DAWN.
THE BEST FIT/MATCH BETWEEN THE AVAILABLE MOISTURE...THE COOLING
TEMPERATURES ALOFT...AND THE MID LEVEL VORT MAXIMUMS SEEM TO
BE OVER EASTERN OHIO AND INTO NORTHERN/NORTHWESTERN WEST VIRGINIA
THIS AFTERNOON INTO THIS EVENING. THE EQUILIBRIUM LEVEL IS ABOUT 3
TO 4 TSHD FT HIGHER ACROSS THE NORTH COMPARED TO THE SOUTH...
REACHING AROUND 28/29 THOUSAND IN THE NORTH. SO TALL/COLD AUGUST
CONVECTION IS NOT EXPECTED HOWEVER...WITH THE FREEZING LEVEL LOWER
THAN NORMAL...AROUND 10 THSD FT...SOME LOCALIZED HAIL IS
POSSIBLE...DESPITE THE RELATIVELY LOW EL FOR AUGUST.
SO RAISED POPS INTO THE 40 PERCENT RANGE ACROSS THE NORTH...WITH
20/30 POPS FURTHER SOUTH. WILL LINGER THOSE POPS WELL INTO THE
EVENING.
WILL NOT GET TOO FANCY WITH THE LATE NIGHT FOG FOR MONDAY
NIGHT...SINCE IT WILL DEPEND ON THE RAIN COVERAGE. YET...PLACES
LIKE THE COOL MOUNTAIN VALLEYS SHOULD GO DOWN AGAIN.
NO BIG CHANGES ON TEMPERATURES. WAS THINKING TODAY SHOULD BE NO
WARMER...BUT MAYBE A FEW DEGREES COOLER THAN SUNDAY.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
500MB TROUGH AXIS EXPECTED TO PUSH THROUGH TUESDAY INTO WEDNESDAY.
WITH SOME LINGERING LOW TO MID LEVEL MOISTURE...HAVE SLIGHT CHANCE
TO CHANCE POPS ACROSS FORECAST AREA TUESDAY INTO TUESDAY NIGHT.
FOLLOWING TROUGH PASSAGE...SETTLE INTO WEAK FLOW ALOFT WITH A
SURFACE HIGH BUILDING IN TO PROVIDE MAINLY DRY WEATHER. WITH THAT
SAID...COULD STILL SEE SOME ISOLATED SHOWERS OR THUNDERSTORMS IN THE
MOUNTAINS...MAINLY ON WEDNESDAY AFTERNOON. WILL SEE A GRADUAL
WARMING TREND THROUGH MID-WEEK AS HEIGHTS RISE AND WE SEE PLENTY OF
SUNSHINE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
USED A BLEND OF THE GEFS MEAN...ECMWF AND ECMWF MEAN. THIS LEAVES A
WEAK HIGH PRESSURE SYSTEM OVER THE REGION FOR THURSDAY AND FRIDAY...
BUT POSSIBLY ENOUGH MOISTURE TO FIRE SOME AFTERNOON
SHOWERS/THUNDERSTORMS IN THE MOUNTAINS. BY THE WEEKEND...A SOUTHERLY
FLOW IN ADVANCE OF AN APPROACHING SYSTEM MAY PROVIDE ENOUGH
MOISTURE FOR SHOWERS OR THUNDERSTORMS THROUGHOUT THE REGION.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
VORT MAX PULLING NE THRU UPPER OHIO RIVER VALLEY...WILL LEAVE THE
POSSIBILITY OF A SHOWER REST OF THE NIGHT IN NORTHERN WEST
VIRGINIA.
HAVE CLOUDS CLEARING IN THE SOUTH...SO WILL GO STRONGER ON THE FOG
INCLUDING CRW.
THE SOUTHERN MOUNTAINS AROUND BECKLEY ARE TOUGH TO FIGURE FOR THE
PREDAWN HOURS. ALSO HAVE MID DECK CLEARING...BUT THE SE FLOW STARTS
TO BREAK DOWN. WITH THE VERY WEAK LOW LEVEL FLOW...DO NOT HAVE A
LOT OF CONFIDENCE IN THE AMOUNT AND HEIGHT OF LOWER STRATUS FORMING
DURING THE 06Z TO 12Z. TRIED TO DELAY THAT FORMATION...BUT VALLEY
FOG COULD ALSO FORM.
WITH THE COMBINATION OF THE COOLER MID LEVEL TEMPERATURES AND A BIT
MORE MOISTURE...WENT A BIT HIGHER ON POPS FOR MONDAY ACROSS EASTERN
OHIO AND NORTHERN WEST VIRGINIA THAN PREVIOUSLY...AND ALSO HIGHER
THAN COUNTIES FURTHER TO THE SOUTH.
SCATTERED SHOWERS SHOULD BE PREVALENT...BUT WITH EQUILIBRIUM LEVELS
AROUND 25 THSD...ALSO SOME THUNDER.
HAVE CONVECTION WEAKENING 00Z TO 02Z TUESDAY...AND THEN
AGAIN...ANOTHER FOG ISSUE/HEADACHE BY 06Z TUESDAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: THICKER FOG IN THE CLEARING OVER SOUTHERN WEST
VIRGINIA FOR THE PREDAWN HOURS THIS MORNING.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE MON 08/20/12
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY H H L L L L M L H H H H
HTS CONSISTENCY H H H L L L H H H H H H
BKW CONSISTENCY H H M H L L L H M H H H
EKN CONSISTENCY M H M L L L M L H H H H
PKB CONSISTENCY H H L L L L M H H H H H
CKB CONSISTENCY H H H H H L H H H H H H
AFTER 06Z TUESDAY...
BRIEF IFR CONDITIONS POSSIBLE IN THUNDERSTORMS TUESDAY AFTERNOON.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB
SHORT TERM...MZ
LONG TERM...RPY
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
521 AM EDT MON AUG 20 2012
.SYNOPSIS...
A COLD FRONT WILL SLOWLY SLIDE EAST OF THE SOUTHERN APPALACHIAN
REGION ON TUESDAY. WEAK HIGH PRESSURE WILL BUILD OVER THE WESTERN
CAROLINAS AND NORTHEAST GEORGIA BY MID WEEK AND REMAIN THROUGH THIS
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 520 AM EDT...RAIN CONTINUES ACROSS THE I-77 CORRIDOR...THOUGH
THE BACK EDGE OF THE PCPN CONTINUES TO SLOWLY MOVE EAST. UPPED POPS
FOR A FEW MORE HOURS TO ACCOUNT FOR THE BACK EDGE OF THE FRONTAL
BAND PCPN. ALSO CUT BACK ON FOG A LITTLE OUT INTO THE PIEDMONT WHERE
MID LEVEL CLOUDS PROBABLY WON/T CLEAR UNTIL AFTER SUNRISE.
PREVIOUS DISCUSSION...
RAIN IS BECOMING MORE WIDESPREAD OVER THE SRN UPSTATE AND NC
PIEDMONT THOUGH THE AREA OF PCPN IS STILL EXHIBITING A GRADUAL PUSH
TO THE EAST. IT APPEARS THAT THE SHORT WAVE ERN TN...EVIDENT IN
DRYING IN THE WATER VAPOR IMAGERY...IS HELPING TO ENHANCE UPPER
DIVERGENCE IN THE ENTRANCE REGION OF THE JET. THE HRRR HAS PICKED UP
ON THIS AREA OF PCPN AND IS ALSO SHOWING A SLOW EASTWARD MOVEMENT.
THEREFORE...THE PCPN SHOULD GRADUALLY CLEAR THE EASTERN ZONES BY
SUNRISE. ACROSS THE MOUNTAINS AND FOOTHILLS AREAS OF DENSE FOG WILL
LIKELY DEVELOP AS THE UPPER LEVEL SUBSIDENCE PUSHES INTO THE WRN
ZONES. AGEOSTROPHIC FLOW ORIENTED FROM THE NW ON THE SUBSIDENCE SIDE
OF THE JET IS CONTRIBUTING TO SOME MIXING AND DRY AIR ADVECTION
ACROSS THE FRENCH BROAD VALLEY. I SUSPECT THIS WILL WEAKEN AS THE
WAVE PUSHES TO THE EAST AND FOG SHOULD SET UP EVEN IN THE LARGE
VALLEYS SOON.
LATER TODAY THE SFC FRONT...WHICH HAS NOW MOVED INTO THE SRN PART OF
THE UPSTATE...WILL LIFT BACK TO THE NORTH. THIS SHOULD RESULT IN
GOOD LLVL CONVERGENCE ROUGHLY ALONG THE I-85 CORRIDOR AND I SUSPECT
THAT SCT LATE AFTN AND EVENING TSTMS WILL DEVELOP IN THIS AREA.
CONVECTION MAY LAST A WAYS INTO THE OVERNIGHT PERIOD AS THE NAM
SHOWS IMPROVING LLVL CONVERGENCE THIS EVENING WITH THE FRONT
BECOMING MORE DEFINED. OVER THE MTNS LOWER DEWPOINT AIR BEHIND THE
BNDRY WILL RESULT IN A PLEASANTLY COOL NIGHT WITH LOWS FALLING INTO
THE LOWER TO MID 50S IN MANY LOCATIONS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 230 AM MONDAY...ON TUESDAY...THE MID LEVEL TROF AXIS IS
EXPECTED TO RUN ACROSS THE OHIO RIVER AND MISSISSIPPI RIVER VALLEYS
DURING THE AFTERNOON. THE GFS AND ECMWF INDICATES THAT THE REGION
EAST OF THE TROF WILL SEE AN IMPRESSIVE LATE SUMMER JET...WITH A
LONG BAND OF UPPER DIVERGENCE ALONG AND WEST OF THE ATLANTIC COAST.
HIGH TEMPERATURES IN THE MID 80S AND DEWPOINTS IN THE L60S SHOULD
YIELD WEAK TO MODERATE AFTERNOON INSTABILITY. THE COMBINATION OF THE
UPPER FORCING AND INSTABILITY SHOULD SUPPORT SCT
SHRA/TSRA...ESPECIALLY EAST OF I-85. CONVECTION SHOULD DISSIPATE
THROUGH THE EVENING HOURS...BUT ISOLATED COVERAGE COULD CONTINUE
ACROSS THE PIEDMONT INTO EARLY WED MORNING. LOW TEMPERATURES ARE
FORECAST TO RANGE FROM THE U50S ACROSS THE MTNS VALLEYS TO THE MID
60S EAST.
ON WEDNESDAY...THE H5 TROF AXIS WILL MOVE OVER THE SOUTHERN
APPALACHIAN REGION DURING THE AFTERNOON. A VORT MAX WITHIN THE TROF
AXIS WILL LIKELY RIPPLE OVER THE MTNS DURING THE LATE AFTERNOON.
HIGH TEMPERATURES MAY RANGE A DEGREE OR TWO WARMER THAN TUESDAY WITH
DEWPOINTS IN THE LOWER TO MID 60S. GFS CAPE VALUES SHOULD ARE
FORECAST TO RANGE AROUND 1000 J/KG. BASED ON WEAK DIURNAL
INSTABILITY AND THE APPROACH OF A WEAK MID LEVEL DISTURBANCE I WILL
FORECAST A DIURNAL SCHC ACROSS THE CWA...WITH CHC POPS ACROSS THE
HIGHEST ELEVATIONS. CONVECTION SHOULD COME TO AN END DURING THE LATE
EVENING. WEDNESDAY NIGHT IS FORECAST TO REMAIN DRY...CALM...AND MIN
TEMPS AROUND 3-5 DEGREES BELOW NORMAL.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 245 AM MONDAY...WEAK MID LEVEL RIDGING WILL BUILD OVER THE
REGION THURSDAY THROUGH SUNDAY. AT THE SFC...BROAD HIGH PRESSURE
CENTERED OVER THE MID ATLANTIC STATES WILL RIDGE SW ACROSS THE CWA
THROUGH THE PERIOD. TEMPERATURES EACH AFTERNOON IS EXPECTED TO RANGE
FROM NEAR 80 ACROSS THE MTNS VALLEYS TO THE MID 80S EAST. DEWPOINTS
WILL ALSO RANGE IN THE 60S EACH AFTERNOON...YIELDING WEAK TO
MODERATE INSTABILITY. DIURNAL ISO TO CHC CONVECTION IS EXPECTED EACH
DAY...WITH COVERAGE FAVORED OVER THE HIGH TERRAIN.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
AT KCLT...SFC COLD FRONT HAS DROPPED SOUTH OF THE AIRFIELD. IFR CIG
HAS DEVELOPED BEHIND THE FRONT. A FEW BREAKS ARE LIKELY OVER THE
NEXT FEW HOURS...BUT LOWER CIGS SHOULD SETTLE IN BY 0800 UTC WITH A
LIGHT NE WIND. A SHRA IS POSSIBLE AT THE AIRFIELD THE REST OF THE
NIGHT...THOUGH MOST OF THE ACTIVITY IS NOW MAINLY E AND WEST OF THE
AIRFIELD AND IS MOVING VERY LITTLE. THE LOW CIGS SHOULD GRADUALLY
LIFT DURING THE MORNING HOURS OR THEY MAY SIMPLY BURN OFF AS THE LOW
CLOUD DECK SHOULDN/T BE VERY DEEP. THE FRONT WILL LIFT BACK NORTH
VERY CLOSE TO KCLT IN THE AFTN HOURS. SCT TSTMS ARE EXPECTED TO
DEVELOP IN THE AFTN AND LAST WELL INTO THE EVENING.
ELSEWHERE...A SFC COLD FRONT HAS MOVED THROUGH THE NC ZONES AND WAS
LOCATED JUST SOUTH OF KGSP AT ISSUANCE TIME. THE FRONT WILL CONTINUE
TO DRIFT TO THE SOUTH THIS MORNING. AT KAVL AND KHKY DENSE FOG IS
EXPECTED TO DEVELOP AS MID LEVEL DRYING OCCURS...AND THIS HAS BEEN
TIMED ROUGHLY WITH THE BACK EDGE OF THE HIGH CLOUDS. OVER THE
UPSTATE...STRATUS WILL GRADUALLY FILL IN BEHIND THE FRONT...THOUGH
THIS WILL TAKE A FEW HOURS...ESPECIALLY AS A BRIEF MODERATE SHRA OR
TWO IS POSSIBLE AT ANY OF THE AIRFIELDS. BY AROUND 0900 UTC OR SO A
MORE UNIFORM IFR STRATUS DECK IS EXPECTED TO DEVELOP. WINDS WILL BE
LIGHT NE BEHIND THE FRONT...BUT THEY WILL SHIFT TO THE SOUTHWEST BY
LATE MORNING AS THE FRONT MOVES BACK NORTH. SCT TSTMS ARE EXPECTED
ALONG THE FRONT THIS AFTN AND PROB30S HAVE BEEN ADDED EVERYWHERE TO
ACCOUNT FOR THIS.
OUTLOOK...A WEAK STATIONARY BOUNDARY WILL LINGER ACROSS THE REGION
THROUGH THE EARLY WEEK. SFC LOWS MAY TRACK ALONG THE
FRONT...SUPPORTING PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH
TUESDAY. IN ADDITION...THE FORMATION OF LOW CLOUDS AND FOG IS
POSSIBLE EACH MORNING...ESPECIALLY NEAR AREAS OF RECENT RAINFALL.
CONDITIONS SHOULD IMPROVE WED AND THU.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...NED
NEAR TERM...MCAVOY
SHORT TERM...NED
LONG TERM...NED
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
350 AM EDT MON AUG 20 2012
.SYNOPSIS...
A COLD FRONT WILL SLOWLY SLIDE EAST OF THE SOUTHERN APPALACHIAN
REGION ON TUESDAY. WEAK HIGH PRESSURE WILL BUILD OVER THE WESTERN
CAROLINAS AND NORTHEAST GEORGIA BY MID WEEK AND REMAIN THROUGH THIS
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
RAIN IS BECOMING MORE WIDESPREAD OVER THE SRN UPSTATE AND NC
PIEDMONT THOUGH THE AREA OF PCPN IS STILL EXHIBITING A GRADUAL PUSH
TO THE EAST. IT APPEARS THAT THE SHORT WAVE ERN TN...EVIDENT IN
DRYING IN THE WATER VAPOR IMAGERY...IS HELPING TO ENHANCE UPPER
DIVERGENCE IN THE ENTRANCE REGION OF THE JET. THE HRRR HAS PICKED UP
ON THIS AREA OF PCPN AND IS ALSO SHOWING A SLOW EASTWARD MOVEMENT.
THEREFORE...THE PCPN SHOULD GRADUALLY CLEAR THE EASTERN ZONES BY
SUNRISE. ACROSS THE MOUNTAINS AND FOOTHILLS AREAS OF DENSE FOG WILL
LIKELY DEVELOP AS THE UPPER LEVEL SUBSIDENCE PUSHES INTO THE WRN
ZONES. AGEOSTROPHIC FLOW ORIENTED FROM THE NW ON THE SUBSIDENCE SIDE
OF THE JET IS CONTRIBUTING TO SOME MIXING AND DRY AIR ADVECTION
ACROSS THE FRENCH BROAD VALLEY. I SUSPECT THIS WILL WEAKEN AS THE
WAVE PUSHES TO THE EAST AND FOG SHOULD SET UP EVEN IN THE LARGE
VALLEYS SOON.
LATER TODAY THE SFC FRONT...WHICH HAS NOW MOVED INTO THE SRN PART OF
THE UPSTATE...WILL LIFT BACK TO THE NORTH. THIS SHOULD RESULT IN
GOOD LLVL CONVERGENCE ROUGHLY ALONG THE I-85 CORRIDOR AND I SUSPECT
THAT SCT LATE AFTN AND EVENING TSTMS WILL DEVELOP IN THIS AREA.
CONVECTION MAY LAST A WAYS INTO THE OVERNIGHT PERIOD AS THE NAM
SHOWS IMPROVING LLVL CONVERGENCE THIS EVENING WITH THE FRONT
BECOMING MORE DEFINED. OVER THE MTNS LOWER DEWPOINT AIR BEHIND THE
BNDRY WILL RESULT IN A PLEASANTLY COOL NIGHT WITH LOWS FALLING INTO
THE LOWER TO MID 50S IN MANY LOCATIONS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 230 AM MONDAY...ON TUESDAY...THE MID LEVEL TROF AXIS IS
EXPECTED TO RUN ACROSS THE OHIO RIVER AND MISSISSIPPI RIVER VALLEYS
DURING THE AFTERNOON. THE GFS AND ECMWF INDICATES THAT THE REGION
EAST OF THE TROF WILL SEE AN IMPRESSIVE LATE SUMMER JET...WITH A
LONG BAND OF UPPER DIVERGENCE ALONG AND WEST OF THE ATLANTIC COAST.
HIGH TEMPERATURES IN THE MID 80S AND DEWPOINTS IN THE L60S SHOULD
YIELD WEAK TO MODERATE AFTERNOON INSTABILITY. THE COMBINATION OF THE
UPPER FORCING AND INSTABILITY SHOULD SUPPORT SCT
SHRA/TSRA...ESPECIALLY EAST OF I-85. CONVECTION SHOULD DISSIPATE
THROUGH THE EVENING HOURS...BUT ISOLATED COVERAGE COULD CONTINUE
ACROSS THE PIEDMONT INTO EARLY WED MORNING. LOW TEMPERATURES ARE
FORECAST TO RANGE FROM THE U50S ACROSS THE MTNS VALLEYS TO THE MID
60S EAST.
ON WEDNESDAY...THE H5 TROF AXIS WILL MOVE OVER THE SOUTHERN
APPALACHIAN REGION DURING THE AFTERNOON. A VORT MAX WITHIN THE TROF
AXIS WILL LIKELY RIPPLE OVER THE MTNS DURING THE LATE AFTERNOON.
HIGH TEMPERATURES MAY RANGE A DEGREE OR TWO WARMER THAN TUESDAY WITH
DEWPOINTS IN THE LOWER TO MID 60S. GFS CAPE VALUES SHOULD ARE
FORECAST TO RANGE AROUND 1000 J/KG. BASED ON WEAK DIURNAL
INSTABILITY AND THE APPROACH OF A WEAK MID LEVEL DISTURBANCE I WILL
FORECAST A DIURNAL SCHC ACROSS THE CWA...WITH CHC POPS ACROSS THE
HIGHEST ELEVATIONS. CONVECTION SHOULD COME TO AN END DURING THE LATE
EVENING. WEDNESDAY NIGHT IS FORECAST TO REMAIN DRY...CALM...AND MIN
TEMPS AROUND 3-5 DEGREES BELOW NORMAL.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 245 AM MONDAY...WEAK MID LEVEL RIDGING WILL BUILD OVER THE
REGION THURSDAY THROUGH SUNDAY. AT THE SFC...BROAD HIGH PRESSURE
CENTERED OVER THE MID ATLANTIC STATES WILL RIDGE SW ACROSS THE CWA
THROUGH THE PERIOD. TEMPERATURES EACH AFTERNOON IS EXPECTED TO RANGE
FROM NEAR 80 ACROSS THE MTNS VALLEYS TO THE MID 80S EAST. DEWPOINTS
WILL ALSO RANGE IN THE 60S EACH AFTERNOON...YIELDING WEAK TO
MODERATE INSTABILITY. DIURNAL ISO TO CHC CONVECTION IS EXPECTED EACH
DAY...WITH COVERAGE FAVORED OVER THE HIGH TERRAIN.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
AT KCLT...SFC COLD FRONT HAS DROPPED SOUTH OF THE AIRFIELD. IFR CIG
HAS DEVELOPED BEHIND THE FRONT. A FEW BREAKS ARE LIKELY OVER THE
NEXT FEW HOURS...BUT LOWER CIGS SHOULD SETTLE IN BY 0800 UTC WITH A
LIGHT NE WIND. A SHRA IS POSSIBLE AT THE AIRFIELD THE REST OF THE
NIGHT...THOUGH MOST OF THE ACTIVITY IS NOW MAINLY E AND WEST OF THE
AIRFIELD AND IS MOVING VERY LITTLE. THE LOW CIGS SHOULD GRADUALLY
LIFT DURING THE MORNING HOURS OR THEY MAY SIMPLY BURN OFF AS THE LOW
CLOUD DECK SHOULDN/T BE VERY DEEP. THE FRONT WILL LIFT BACK NORTH
VERY CLOSE TO KCLT IN THE AFTN HOURS. SCT TSTMS ARE EXPECTED TO
DEVELOP IN THE AFTN AND LAST WELL INTO THE EVENING.
ELSEWHERE...A SFC COLD FRONT HAS MOVED THROUGH THE NC ZONES AND WAS
LOCATED JUST SOUTH OF KGSP AT ISSUANCE TIME. THE FRONT WILL CONTINUE
TO DRIFT TO THE SOUTH THIS MORNING. AT KAVL AND KHKY DENSE FOG IS
EXPECTED TO DEVELOP AS MID LEVEL DRYING OCCURS...AND THIS HAS BEEN
TIMED ROUGHLY WITH THE BACK EDGE OF THE HIGH CLOUDS. OVER THE
UPSTATE...STRATUS WILL GRADUALLY FILL IN BEHIND THE FRONT...THOUGH
THIS WILL TAKE A FEW HOURS...ESPECIALLY AS A BRIEF MODERATE SHRA OR
TWO IS POSSIBLE AT ANY OF THE AIRFIELDS. BY AROUND 0900 UTC OR SO A
MORE UNIFORM IFR STRATUS DECK IS EXPECTED TO DEVELOP. WINDS WILL BE
LIGHT NE BEHIND THE FRONT...BUT THEY WILL SHIFT TO THE SOUTHWEST BY
LATE MORNING AS THE FRONT MOVES BACK NORTH. SCT TSTMS ARE EXPECTED
ALONG THE FRONT THIS AFTN AND PROB30S HAVE BEEN ADDED EVERYWHERE TO
ACCOUNT FOR THIS.
OUTLOOK...A WEAK STATIONARY BOUNDARY WILL LINGER ACROSS THE REGION
THROUGH THE EARLY WEEK. SFC LOWS MAY TRACK ALONG THE
FRONT...SUPPORTING PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH
TUESDAY. IN ADDITION...THE FORMATION OF LOW CLOUDS AND FOG IS
POSSIBLE EACH MORNING...ESPECIALLY NEAR AREAS OF RECENT RAINFALL.
CONDITIONS SHOULD IMPROVE WED AND THU.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...NED
NEAR TERM...MCAVOY
SHORT TERM...NED
LONG TERM...NED
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
205 AM EDT MON AUG 20 2012
.SYNOPSIS...
A COLD FRONT WILL REMAIN STALLED OVER THE WESTERN CAROLINAS THROUGH
TUESDAY. A SERIES OF WEAK LOWS WILL MOVE UP THE FRONTAL BOUNDARY
THROUGH TUESDAY. BY MID WEEK THE FRONT WILL GRADUALLY MOVE TO THE
COAST ALLOWING WEAK HIGH PRESSURE TO BUILD INTO THE REGION FROM THE
WEST.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 200 AM...EXTENSIVE LIGHT TO MODERATE RAIN AND A FEW AREAS OF
HEAVIER SHOWERS CONTINUE ACROSS THE SE THIRD OF THE FORECAST AREA.
THERE IS ALSO A SECONDARY BAND OF RAIN AND SHRA ACROSS THE CENTRAL
PART OF THE FA. THIS IS THE RESULT OF FRONTOGENESIS AT A COUPLE
DIFFERENT LEVELS OF THE ATMOSPHERE I SUSPECT. PCPN SHOULD GRADUALLY
PUSH TO THE EAST...BUT THE ERN ZONES SHOULD SEE PCPN LAST THROUGH
SUNRISE AND THE POPS HAVE BEEN RAISED OVERNIGHT.
AT OF 1045 PM...PER AN INTERMEDIATE UPDATE WE SLOWED THE ADVANCE
EAST OF THE PRECIPITATION OUT OF OUR FORECAST AREA (FA) OVERNIGHT
AS NEXT WAVE SURGES NEWD IN PSEUDO TROPICAL PLUME OF MOISTURE.
RAINFALL CONTINUES TORRENTIAL IN SOME SPOTS...BUT IT IS LOCALIZED
AND DOES NOT REQUIRE AN AREAL WATCH. EVENTUALLY HEAVY SHOWERS WILL
BECOME FOCUSED IN OUR FAR SOUTH AND EAST FORECAST AREA AFTER
MIDNIGHT. ON OUR WESTERN FLANK...MIXED SIGNALS ABOUT HOW MUCH
CLEARING WILL TAKE PLACE. IT MAY VERY WELL WORK OUT THAT JUST ENOUGH
CLOUDS HOLD TO KEEP WIDESPREAD VISIBILITIES FROM GETTING OUT OF
HAND. HOWEVER CONFIDENCE IS LOW WITH MODEL VARIABILITY SUGGESTING
VARIOUS SOLUTION. WE WILL CONTINUE TO MENTION FOG IN THE FORECAST
BUT NO HEADLINES ATTM. COORDINATION WITH RNK.
AS OF 800 PM...MESO ANALYSIS HAS WAVY BACKDOOR FRONT DROPPING
THROUGH OUR EASTERN FORECAST AREA (FA) ALONG WITH A SLIGHT UPTICK IN
MAINLY SHOWERS...SOME WITH HEAVY RAIN. WE/VE ADJUSTED OUR WIND
FORECAST TO BRING THE FRONT...ON OUR EASTERN FLANK...TO THE NC/SC
STATE LINE. IT APPEARS THE RAP MODEL IS HANDLING THIS FEATURE THE
BEST. OTHERWISE SCATTERED SHOWERS CONTINUE...MOST NUMEROUS IN THE NC
FOOTHILLS AND THE UPSTATE OF SC. THE QUESTION IS WHAT TO DO WITH THE
WATER VAPOR IMAGERY WAVE LIFTING FROM SOUTHERN MISSISSIPPI...TO THE
NE? IN THE VERY SHORT TERM WE ARE IN GOOD SHAPE...BUT MAY HAVE TO
SLOW DOWN THE POP DECREASING TREND A BIT...PARTICULARLY FAR SOUTH
AND EAST FA. TEMPERATURES STILL APPEAR ON TARGET.
AS OF 500 PM...MESO SCALE MODELS SHOWING POTENTIAL FLAIR-UP...OR AN
UPTICK IN CONVECTIVE POTENTIAL...ACROSS OUR EASTERN AND SOUTHERN
FORECAST AREA (FA). SURFACE BASED CAPES ARE INCHING UPWARD WITH SOME
BREAKS IN THE CLOUDS...HOWEVER NOT A LARGE INCREASE IN CONVECTION
HAS YET BEEN NOTED. WE WILL CONTINUE TO RUN THE COURSE WITH A MEDIUM
RANGE POP INTO THE EARLY EVENING...BANKING ON OVERALL CLOUDS (BIG
PICTURE) TO KEEP THINGS AT BAY. THIS WAS PRESENTED IN THE EARLIER
FORECAST...AND ONLY MINOR CHANGES ARE NEEDED. MINOR ADJUSTMENTS ON
TEMPERATURES AS WELL TO MIRROR CURRENT TRENDS.
AS OF 220 PM...SCATTERED SHOWERS CONTINUE TO DEVELOP ACROSS THE
AREA...MAINLY ASSOCIATED WITH THE DEEPER MOISTURE AND WEAK
INSTABILITY ALONG/EAST OF I-85. POPS WILL RANGE FROM LOW CHANCE
ACROSS THE NORTH TO HIGH CHANCE ACROSS THE SOUTH INTO THE EVENING
HOURS. AS EXPECTED...WIDESPREAD CLOUD COVER HAS LIMITED
DESTABILIZATION ACROSS THE AREA...BUT THANKS TO SOME BREAKS IN THE
OVC...CAPE VALUES ARE EDGING CLOSER TO 1000 J/KG ACROSS THE SOUTHERN
ZONES PER LATEST SPC MESOANALYSIS. EXPECT THUNDERSTORMS TO DEVELOP
AND GRADUALLY EXPAND IN COVERAGE THIS AFTERNOON...BUT STORMS SHOULD
REMAIN ISOLATED TO WIDELY SCATTERED. DEEP LAYER BULK SHEAR REMAINS
QUITE HIGH FOR THIS TIME OF YEAR (AROUND 40 KT)...SO IF CAPE VALUES
CAN NUDGE A LITTLE CLOSER TO 2000 J/KG...WE COULD SEE AN ISOLATED
SEVERE THREAT ACROSS OUR SOUTHERN ZONES. HOWEVER...THIS DOESN/T
APPEAR LIKELY.
CONVECTION WILL GRADUALLY DIMINISH THIS EVENING...AS MID/UPPER LEVEL
DRY AIR ADVECTION OVERSPREADS THE AREA...AND FORCING REMAINS
RELATIVELY WEAK. DEPENDING UPON HOW QUICKLY THE HIGHER CLOUDS
DISSIPATE...WE COULD BE SETTING UP FOR A DENSE FOG EVENT ACROSS
PORTIONS OF THE CWA LATE TONIGHT.
BY MONDAY MORNING...THE UPPER JET AXIS SHIFTS TO THE APPALACHIANS.
THIS RESULTS IN SHUNTING OF THE DEEPER MOISTURE AND BETTER FORCING
TOWARD THE COAST. QPF RESPONSE IS THEREFORE LIMITED ACROSS OUR AREA
IN MOST MODEL SOLUTIONS. IN FACT...THE LEAST RUNS OF THE SREF AND
ECMWF ARE PRACTICALLY BONE DRY IN OUR CWA. HOWEVER...THE UPPER
TROUGH AXIS WILL REMAIN TO OUR WEST...WHILE DRYING ALOFT SHOULD
ALLOW FOR MUCH MORE SUN TOMORROW THAN WE HAVE SEEN TODAY. THIS
SHOULD RESULT IN MODERATE INSTABILITY DEVELOPING BY AFTERNOON.
ALTHOUGH THIS MAY SUPPORT SCATTERED DIURNAL CONVECTION...IT DOES
APPEAR THAT WE NEED TO BACK OFF THE LIKELY POPS WE HAVE BEEN
ADVERTISING FOR MONDAY. MORE SUN ON MONDAY WILL ALLOW FOR WARMER MAX
TEMPS...BUT THESE SHOULD STILL BE ABOUT A CATEGORY BELOW NORMAL
UNDER THE DEEP LONG WAVE TROUGH.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
AS OF 130 PM SUNDAY...AN UPPER JETLET WILL BISECT THE FORECAST AREA
MON NIGHT THROUGH TUE...WITH UPPER DIVERGENCE FOCUSED MAINLY OVER
OUR ERN PIEDMONT. THE BEST CHC POPS WILL BE OVER THE ERN PART OF THE
FORECAST AREA IN THE DEEPER MOISTURE AND ALSO OVER THE NRN MTNS WITH
THE ARRIVAL OF A MORE POTENT VORTICITY LOBE IN THE TROUGH AXIS TO
THE WEST. TUE AFTN MAX TEMPS SHOULD RISE A CATEGORY OR SO ABOVE MON
VALUES.
THE NRN TIER SHORTWAVE WILL LIFT NE OF THE REGION INTO WED...BUT
WITH ADDITIONAL UPSTREAM TROUGHINESS CARVING OUT AS THE NEXT WAVE
MOVES OVER THE MS RIVER TOWARD THE SE. PROFILES APPEAR QUITE A BIT
DRIER AHEAD OF THIS SYSTEM...SO WILL FEATURE MAINLY DIURNALLY DRIVEN
ISOLD TSTMS...WITH LOCAL MAXIMA OF COVERAGE ALONG THE MTN RIDGES AND
THE EXTREME SE PIEDMONT. MAX TEMPS SHOULD GAIN ANOTHER DEGREE OR SO
OVER TUE VALUES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 145 PM SUNDAY...SHORTWAVE RIDGING SHOULD RETURN FROM THE WEST
THU THROUGH FRI...AND POSSIBLY LINGER INTO NEXT WEEKEND. WEAK HIGH
PRESSURE WILL ALSO BUILD DOWN FROM THE N THROUGH THE PERIOD. WILL
FEATURE MAX TEMPS A TOUCH WARMER THAN PREVIOUSLY FOR THU THROUGH SAT
GIVEN THE BETTER INSOLATION UNDER THE SHALLOW UPPER RIDGE. EXPECT
LITTLE MORE THAN DIURNAL ISOLD WEAK CONVECTION...WITH COVERAGE BEST
ALONG THE MTN RIDGES.
MODEL UNCERTAINTY BUILDS THROUGH NEXT WEEKEND...WITH THE ECM
FEATURING A SHORTWAVE DEVELOPING OVER THE MID MS RIVER VALLEY ON SAT
WHICH IT MOVES INTO THE SRN APPALACHIANS ON SUNDAY. THE GFS PHASES
THIS SYSTEM BACK INTO THE NRN STREAM AND KEEPS A FLAT UPPER RIDGE IN
PLACE THROUGH SUNDAY. THE CMC/GEFS AND HPC LEAN TOWARD THE ECM
SOLUTION...SO WILL ADVERTISE SLOWLY RISING CHC POPS THROUGH LATE
SUNDAY ALONG WITH COOLER THAN MOS TEMPS.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AT KCLT...SFC COLD FRONT HAS DROPPED SOUTH OF THE AIRFIELD. IFR CIG
HAS DEVELOPED BEHIND THE FRONT. A FEW BREAKS ARE LIKELY OVER THE
NEXT FEW HOURS...BUT LOWER CIGS SHOULD SETTLE IN BY 0800 UTC WITH A
LIGHT NE WIND. A SHRA IS POSSIBLE AT THE AIRFIELD THE REST OF THE
NIGHT...THOUGH MOST OF THE ACTIVITY IS NOW MAINLY E AND WEST OF THE
AIRFIELD AND IS MOVING VERY LITTLE. THE LOW CIGS SHOULD GRADUALLY
LIFT DURING THE MORNING HOURS OR THEY MAY SIMPLY BURN OFF AS THE LOW
CLOUD DECK SHOULDN/T BE VERY DEEP. THE FRONT WILL LIFT BACK NORTH
VERY CLOSE TO KCLT IN THE AFTN HOURS. SCT TSTMS ARE EXPECTED TO
DEVELOP IN THE AFTN AND LAST WELL INTO THE EVENING.
ELSEWHERE...A SFC COLD FRONT HAS MOVED THROUGH THE NC ZONES AND WAS
LOCATED JUST SOUTH OF KGSP AT ISSUANCE TIME. THE FRONT WILL CONTINUE
TO DRIFT TO THE SOUTH THIS MORNING. AT KAVL AND KHKY DENSE FOG IS
EXPECTED TO DEVELOP AS MID LEVEL DRYING OCCURS...AND THIS HAS BEEN
TIMED ROUGHLY WITH THE BACK EDGE OF THE HIGH CLOUDS. OVER THE
UPSTATE...STRATUS WILL GRADUALLY FILL IN BEHIND THE FRONT...THOUGH
THIS WILL TAKE A FEW HOURS...ESPECIALLY AS A BRIEF MODERATE SHRA OR
TWO IS POSSIBLE AT ANY OF THE AIRFIELDS. BY AROUND 0900 UTC OR SO A
MORE UNIFORM IFR STRATUS DECK IS EXPECTED TO DEVELOP. WINDS WILL BE
LIGHT NE BEHIND THE FRONT...BUT THEY WILL SHIFT TO THE SOUTHWEST BY
LATE MORNING AS THE FRONT MOVES BACK NORTH. SCT TSTMS ARE EXPECTED
ALONG THE FRONT THIS AFTN AND PROB30S HAVE BEEN ADDED EVERYWHERE TO
ACCOUNT FOR THIS.
OUTLOOK...A WEAK STATIONARY BOUNDARY WILL LINGER ACROSS THE REGION
THROUGH THE EARLY WEEK. SFC LOWS MAY TRACK ALONG THE
FRONT...SUPPORTING PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH
TUESDAY. IN ADDITION...THE FORMATION OF LOW CLOUDS AND FOG IS
POSSIBLE EACH MORNING...ESPECIALLY NEAR AREAS OF RECENT RAINFALL.
CONDITIONS SHOULD IMPROVE WED AND THU.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...MCAVOY
SHORT TERM...HG
LONG TERM...HG
AVIATION...JDL
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
200 AM EDT MON AUG 20 2012
.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN TO OUR SOUTH TONIGHT INTO MONDAY.
AN UPPER AIR DISTURBANCE WILL TRAVEL SOUTHEAST ACROSS OUR REGION
MONDAY AFTERNOON INTO MONDAY NIGHT. THIS WILL RESULT IN SCATTERED
SHOWERS AND THUNDERSTORMS. BY MID WEEK THE FRONT WILL GRADUALLY
MOVE TO THE ATLANTIC COAST...ALLOWING HIGH PRESSURE TO BUILD INTO
THE REGION FROM THE WEST.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 104 AM EDT MONDAY...
SPOTTY AREAS OF LIGHT RAIN DECREASING IN AREA ACROSS THE WEST AND
PARTIAL CLEARING MAY BEGIN ACROSS FAR SW SOON BASED ON LATEST
SATELLITE IMAGERY. ANOTHER LARGER AREA OF LIGHT RAIN MOVING ACROSS
NC FOOTHILLS AND PIEDMONT AND INTO SOUTHSIDE VA...CAPTURED TO SOME
DEGREE BY LATE EVENING RAP MODEL...EXPECTE TO CONTINUE MOVING
NORTHEAST INTO VA PIEDMONT WHILE LIKELY EVENTUALLY DISSIPATING.
INCREASED POPS ACROSS SOUTHEAST NEXT FEW HOURS TO ACCOUNT FOR
THIS. OTHERWISE NO SIGNIFICANT CHANGES.
AS OF 850 PM EDT SUNDAY...
AXIS OF SHOWERS WITH LOCALLY HEAVY RAIN HAVE BEEN LOCKED IN PLACE
THROUGH MUCH OF THE EVENING JUST TO THE NORTHWEST OF THE
BLACKSBURG FORECAST AREA ACROSS PORTIONS OF SOUTHEASTERN WV ALONG
INSTABILITY AXIS BETWEEN COOL WEDGE OF RAIN-COOLED AIR WITH
EASTERLY LOW LEVEL FLOW TO EAST...WITH MILDER AIR JUST TO THE WEST
OVER CENTRAL WV WHERE LIMITED RAINFALL AND BETTER INSOLATION
RESIDED EARLIER TODAY. THIS AREA EXPECTED TO GRADUALLY WEAKEN
THROUGH THE REST OF THE EVENING AS EASTERLY LOW LEVEL WINDS RELAX
WITH PASSAGE OF WEAK SHORT WAVE...AND AS THERMAL GRADIENT RELAXES
WITH ONSET OF NIGHTTIME COOLING. ELSEWHERE...ONLY WIDELY SCATTERED
LIGHT SHOWERS REMAIN...MAINLY ACROSS THE SOUTHERN/SOUTHEASTERN
QUARTER OF THE BLACKSBURG FORECAST AREA.
HOWEVER...LATEST RUN OF THE NAM MODEL...WITH COMPARABLE REFLECTIONS
FROM THE SREF AND LOCALLY RUN WRF MODELS...CONTINUE TO MAINTAIN
THREAT OF AT LEAST ISOLATED TO WIDELY SCATTERED SHOWERS THROUGH
MUCH OF THE NIGHT IN THE NORTH/WEST AND SOUTH/EAST COUNTIES AS
COMBINATION OF UPPER DIVERGENCE UNDER RIGHT ENTRANCE REGION OF
UPPER JET STREAK COMBINES WITH SOME WEAK QUASI-GEOSTROPHIC
FORCING IN 850-700 MILLIBAR LAYER AS UPPER TROF SLOWLY DEEPENS
OVER AREA AND AS YET ANOTHER SERIES OF WEAK UPSTREAM SHORT WAVE
TROFS AND ASSOCIATED DIFFERENTIAL POSITIVE VORTICITY ADVECTION AND
MARGINAL WARM/MOIST ADVECTION APPROACHES THE AREA FROM THE SOUTHWEST.
CURRENT GRIDDED FIELDS MAINTAIN AT LEAST A LOW THREAT FOR MEASURABLE
PRECIPITATION ACROSS THE ENTIRE FORECAST AREA FOR THE REST OF
TONIGHT...AND THIS SEEMS QUITE REASONABLE WITH RESPECT TO THE
ABOVE DISCUSSION.
PLENTY OF MID AND UPPER LEVEL CLOUDS STREAMING BACK NORTHWARD AS
UPPER FLOW BEGINS TO SLOWLY BACK LATER TONIGHT MAY HELP TO LIMIT
EXTENT OF DENSE FOG DEVELOPING WITHIN VERY MOIST AND UNSTIRRED
BOUNDARY LAYER...SO WILL HOLD OFF ISSUING A FOG ADVISORY AT THE
PRESENT TIME...BUT WILL CONTINUE TO MENTION AREAS/PATCHY FOG WHERE
WARRANTED. DEVELOPMENT AND EXTENT OF FOG WILL BE MAXIMIZED ALONG
EASTERN FLANKS OF THE BLUE RIDGE WHERE WEAK UPSLOPING WILL RESULT
IN LOCALIZED IN THE CLOUD CONDITIONS CONSIDERING THE SATURATED
AIRMASS ALREADY IN PLACE.
THE ENTIRE BLACKSBURG FORECAST AREA WILL REMAIN IN THE COOL WEDGE
FOR THE REST OF THE NIGHT...SO WITH ABUNDANT CLOUD COVER...A NEARLY
SATURATED BOUNDARY LAYER...AND NO CHANGE OF AIRMASS...TEMPERATURES
ARE NOT LIKELY TO BUDGE MUCH MORE THAN ANOTHER SEVERAL DEGREES
FROM CURRENT READINGS.
HAVE MADE TYPICAL TWEAKS TO HOURLY GRIDS TO REFLECT CURRENT AND
ANTICIPATED TEMPERATURE/DEW POINT TEMPERATURE PROFILES AS WELL AS TO
REFLECT AREAL QUALIFIERS WHERE WIDELY SCATTERED SHOWERS ARE EXPECTED
TO PERSIST FOR MUCH OF THE REST OF THE NIGHT...OTHERWISE REST OF
GRID PACKAGE UNCHANGED.
AS OF 355 PM EDT SUNDAY...
THE SHORT WAVE TROUGH/UPPER JET DIVERGENCE LIFTS NORTHEAST
TONIGHT. CONVECTION WILL GRADUALLY DIMINISH THIS EVENING INTO
TONIGHT...AS MID/UPPER LEVEL DRY AIR ADVECTION OVERSPREADS THE
AREA...AS FORCING REMAINS RELATIVELY WEAK. SHOWERS WILL PERSIST
THE LONGEST ACROSS THE EASTERN PORTIONS OF THE CWA TONIGHT CLOSEST
TO THE FRONT AND SURFACE LOW TRACK. WITH PLENTY OF LOW LEVEL
MOISTURE AND LIGHT WINDS...ADDED AREAS OF FOG TONIGHT. PLAYED LOW
TEMPERATURES TONIGHT CLOSE TO ADJMETBC WITH READINGS FROM THE MID
50S IN THE MOUNTAINS TO THE LOWER 60S IN THE SOUTHEAST.
DEEP UPPER TROUGH REMAINS ACROSS THE EASTERN U.S. MONDAY. A
SHORTWAVE IN THE MIDWEST WILL ROUND THE BASE OF THE UPPER TROUGH AND
RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS MONDAY AFTERNOON.
RAISED HIGH TEMPERATURES UP A FEW DEGREES ON MONDAY WITH VALUES FROM
THE LOWER 70S IN THE MOUNTAINS TO AROUND 80 DEGREES IN THE PIEDMONT.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 400 PM EDT SUNDAY...
AMPLIFIED UPPER LEVEL TROUGH OVER THE EASTERN CONUS WILL BE THE
DOMINANT WEATHER FEATURE EARLY IN THE PERIOD...THEN WEAKEN MID WEEK
AS HEIGHTS GRADUALLY RISE. ATTENDANT SURFACE FRONT/BAROCLINIC ZONE
WILL REMAIN CONFINED TO OUR SOUTH...DEEPER MOISTURE MAINLY CONFINED
TO THE COASTAL REGIONS OF THE GULF COAST AND SOUTHEAST ATLANTIC
TIDEWATER. IN SPITE OF THIS MOISTURE LIMITATION...SHORT WAVE ENERGY
IS PROGGED TO SPIRAL AROUND THE UPPER TROUGH...SUBJECTING OUR FCST
AREA TO PERIODS OF CLOUD COVER AND SCATTERED SHOWERS. CONFLICTING
SIGNALS EXIST IN THE TIMING OF THE INDIVIDUAL SHORTWAVES...BUT THE
MODELS DO AGREE ON THE LARGER SCALE FEATURES. THAT SAID WILL BROAD
BRUSH POPS BOTH TUESDAY AND WEDNESDAY TO ACCOUNT FOR SHORT WAVE
TIMING UNCERTAINTIES...BUT SIDE WITH THE COOLER MODEL GUIDANCE PER
THE PERSISTENCE OF THE COOLER UPPER LEVEL TROUGH.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 400 PM EDT SUNDAY...
MODEL SOLUTIONS MIXED FOR THE LATTER HALF OF THE WEEK WITH GREATEST
ENSEMBLE SPREAD NEXT WEEKEND. THE GENERAL IDEA HOWEVER SEEMS TO BE A
WEAK MEAN TROF OVER THE ERN CONUS...IN SPITE OF ITS WEAKENING
EARLIER IN THE WEEK. THIS SUGGESTS ANY SHORTWAVE ENERGY WHICH
ARRIVES FROM SYSTEMS PASSING THROUGH SRN CANADA AND THE NRN CONUS
WILL HAVE A CHANCE TO AMPLIFY AS THEY PROGRESS EAST BOUND INTO THE
UPPER LEVEL TROF. THIS IMPLIES WEATHER ACROSS OUR REGION WILL
REMAIN ACTIVE WITH AT LEAST CHC SHRA/TSRA DURING THE PERIOD...MAINLY
DIURNALLY DRIVEN THURSDAY AND FRIDAY...BUT POTENTIALLY MORE
WIDESPREAD FOR NEXT WEEKEND PENDING AMPLIFICATION OF ANY OF THE
SHORTWAVES THAT MOVE DOWNSTREAM FROM THE UPPER MID WEST.
WITH WEAKENING OF THE EASTERN TROF...TRENDED TEMPERATURES UPWARD
CLOSER TO THE SEASONAL NORMS.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 200 AM EDT MONDAY...
CIGS/VSBYS WILL SLOWLY DETERIORATE REMAINDER OF OVERNIGHT WITH
ABUNDANT MSTR STILL AROUND NOT VERY FAR NORTH OF FRONTAL BOUNDARY.
AREAS OF LIGHT SHOWERS ARE DIMINISHING...EXCEPT DAN WHICH WILL
EXPERIENCE SPOTTY SHOWERS THROUGH ABOUT 08Z OR SO...MAYBE REACHING
LYH BUT LIKELY TO REMAIN EAST OR DISSIPATE FIRST. PARTIAL
CLEARING IN WEST WILL HELP PROMOTE IFR TO LIFR VSBYS FOR FAVORED
AIRPORTS SUCH AS LWB AND BCB. BLF MORE UNCERTAIN BUT MAY BE FIRST
TO CLEAR OFF SOMEWHAT SO STICKING WITH MID IFR VSBY FOR NOW. LAMP
GUIDANCE UP A BIT ON VSBYS IN EAST FOR EARLY MORNING HOURS BUT
KEPT LYH AND DAN IN THE IFR RANGE FOR A FEW HOURS DUE TO WETTER
GROUND DUE TO MORE RECENT RAINFALL. WINDS BASICALLY LIGHT AND
VARIABLE...BUT WITH MIXING MONDAY WILL TEND TO HAVE A WESTERLY
COMPONENT...EXPECIALLY IN THE WEST. EAST A LITTLE TRICKIER...WITH
POSSIBLE NORTHEASTERLY COMPONENT INITIALLY...THEN MAYBE WEST LATE.
STILL 5KT OR LESS. A VERY WEAK DISTURBANCE WILL KEEP A SMALL CHANCE
OF SCATTERED SHOWERS AND THUNDERSTORMS IN THE FORECAST DURING THE
AFTERNOON AND EARLY EVENING HOURS MONDAY BUT NOT EXPECTING
COVERAGE TO BE HIGH ENOUGH TO INCLUDE MENTION OF THUNDER OR
PRECIP IN TAF LOCATIONS.
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ON TUESDAY...ISOLATED
AND BRIEF MVFR/IFR CONDITIONS ARE POSSIBLE. BY WEDNESDAY THE COLD
FRONT CONTINUES TO MOVE FURTHER TO OUR EAST. HIGH PRESSURE WILL
THEN BUILD IN FOR THE REMAINDER OF THE PERIOD...WITH MAINLY
VFR/MVFR CONDITIONS EXPECTED AND VERY LITTLE OR NOW CHANCE OF
SHOWERS OR STORMS DEVELOPING.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...KK
NEAR TERM...KK/SK/WERT
SHORT TERM...PM
LONG TERM...PM
AVIATION...CF/SK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
105 AM EDT MON AUG 20 2012
.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN TO OUR SOUTH TONIGHT INTO MONDAY.
AN UPPER AIR DISTURBANCE WILL TRAVEL SOUTHEAST ACROSS OUR REGION
MONDAY AFTERNOON INTO MONDAY NIGHT. THIS WILL RESULT IN SCATTERED
SHOWERS AND THUNDERSTORMS. BY MID WEEK THE FRONT WILL GRADUALLY
MOVE TO THE ATLANTIC COAST...ALLOWING HIGH PRESSURE TO BUILD INTO
THE REGION FROM THE WEST.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 104 AM EDT MONDAY...
SPOTTY AREAS OF LIGHT RAIN DECREASING IN AREA ACROSS THE WEST AND
PARTIAL CLEARING MAY BEGIN ACROSS FAR SW SOON BASED ON LATEST
SATELLITE IMAGERY. ANOTHER LARGER AREA OF LIGHT RAIN MOVING ACROSS
NC FOOTHILLS AND PIEDMONT AND INTO SOUTHSIDE VA...CAPTURED TO SOME
DEGREE BY LATE EVENING RAP MODEL...EXPECTE TO CONTINUE MOVING
NORTHEAST INTO VA PIEDMONT WHILE LIKELY EVENTUALLY DISSIPATING.
INCREASED POPS ACROSS SOUTHEAST NEXT FEW HOURS TO ACCOUNT FOR
THIS. OTHERWISE NO SIGNIFICANT CHANGES.
AS OF 850 PM EDT SUNDAY...
AXIS OF SHOWERS WITH LOCALLY HEAVY RAIN HAVE BEEN LOCKED IN PLACE
THROUGH MUCH OF THE EVENING JUST TO THE NORTHWEST OF THE
BLACKSBURG FORECAST AREA ACROSS PORTIONS OF SOUTHEASTERN WV ALONG
INSTABILITY AXIS BETWEEN COOL WEDGE OF RAIN-COOLED AIR WITH
EASTERLY LOW LEVEL FLOW TO EAST...WITH MILDER AIR JUST TO THE WEST
OVER CENTRAL WV WHERE LIMITED RAINFALL AND BETTER INSOLATION
RESIDED EARLIER TODAY. THIS AREA EXPECTED TO GRADUALLY WEAKEN
THROUGH THE REST OF THE EVENING AS EASTERLY LOW LEVEL WINDS RELAX
WITH PASSAGE OF WEAK SHORT WAVE...AND AS THERMAL GRADIENT RELAXES
WITH ONSET OF NIGHTTIME COOLING. ELSEWHERE...ONLY WIDELY SCATTERED
LIGHT SHOWERS REMAIN...MAINLY ACROSS THE SOUTHERN/SOUTHEASTERN
QUARTER OF THE BLACKSBURG FORECAST AREA.
HOWEVER...LATEST RUN OF THE NAM MODEL...WITH COMPARABLE REFLECTIONS
FROM THE SREF AND LOCALLY RUN WRF MODELS...CONTINUE TO MAINTAIN
THREAT OF AT LEAST ISOLATED TO WIDELY SCATTERED SHOWERS THROUGH
MUCH OF THE NIGHT IN THE NORTH/WEST AND SOUTH/EAST COUNTIES AS
COMBINATION OF UPPER DIVERGENCE UNDER RIGHT ENTRANCE REGION OF
UPPER JET STREAK COMBINES WITH SOME WEAK QUASI-GEOSTROPHIC
FORCING IN 850-700 MILLIBAR LAYER AS UPPER TROF SLOWLY DEEPENS
OVER AREA AND AS YET ANOTHER SERIES OF WEAK UPSTREAM SHORT WAVE
TROFS AND ASSOCIATED DIFFERENTIAL POSITIVE VORTICITY ADVECTION AND
MARGINAL WARM/MOIST ADVECTION APPROACHES THE AREA FROM THE SOUTHWEST.
CURRENT GRIDDED FIELDS MAINTAIN AT LEAST A LOW THREAT FOR MEASURABLE
PRECIPITATION ACROSS THE ENTIRE FORECAST AREA FOR THE REST OF
TONIGHT...AND THIS SEEMS QUITE REASONABLE WITH RESPECT TO THE
ABOVE DISCUSSION.
PLENTY OF MID AND UPPER LEVEL CLOUDS STREAMING BACK NORTHWARD AS
UPPER FLOW BEGINS TO SLOWLY BACK LATER TONIGHT MAY HELP TO LIMIT
EXTENT OF DENSE FOG DEVELOPING WITHIN VERY MOIST AND UNSTIRRED
BOUNDARY LAYER...SO WILL HOLD OFF ISSUING A FOG ADVISORY AT THE
PRESENT TIME...BUT WILL CONTINUE TO MENTION AREAS/PATCHY FOG WHERE
WARRANTED. DEVELOPMENT AND EXTENT OF FOG WILL BE MAXIMIZED ALONG
EASTERN FLANKS OF THE BLUE RIDGE WHERE WEAK UPSLOPING WILL RESULT
IN LOCALIZED IN THE CLOUD CONDITIONS CONSIDERING THE SATURATED
AIRMASS ALREADY IN PLACE.
THE ENTIRE BLACKSBURG FORECAST AREA WILL REMAIN IN THE COOL WEDGE
FOR THE REST OF THE NIGHT...SO WITH ABUNDANT CLOUD COVER...A NEARLY
SATURATED BOUNDARY LAYER...AND NO CHANGE OF AIRMASS...TEMPERATURES
ARE NOT LIKELY TO BUDGE MUCH MORE THAN ANOTHER SEVERAL DEGREES
FROM CURRENT READINGS.
HAVE MADE TYPICAL TWEAKS TO HOURLY GRIDS TO REFLECT CURRENT AND
ANTICIPATED TEMPERATURE/DEW POINT TEMPERATURE PROFILES AS WELL AS TO
REFLECT AREAL QUALIFIERS WHERE WIDELY SCATTERED SHOWERS ARE EXPECTED
TO PERSIST FOR MUCH OF THE REST OF THE NIGHT...OTHERWISE REST OF
GRID PACKAGE UNCHANGED.
AS OF 355 PM EDT SUNDAY...
THE SHORT WAVE TROUGH/UPPER JET DIVERGENCE LIFTS NORTHEAST
TONIGHT. CONVECTION WILL GRADUALLY DIMINISH THIS EVENING INTO
TONIGHT...AS MID/UPPER LEVEL DRY AIR ADVECTION OVERSPREADS THE
AREA...AS FORCING REMAINS RELATIVELY WEAK. SHOWERS WILL PERSIST
THE LONGEST ACROSS THE EASTERN PORTIONS OF THE CWA TONIGHT CLOSEST
TO THE FRONT AND SURFACE LOW TRACK. WITH PLENTY OF LOW LEVEL
MOISTURE AND LIGHT WINDS...ADDED AREAS OF FOG TONIGHT. PLAYED LOW
TEMPERATURES TONIGHT CLOSE TO ADJMETBC WITH READINGS FROM THE MID
50S IN THE MOUNTAINS TO THE LOWER 60S IN THE SOUTHEAST.
DEEP UPPER TROUGH REMAINS ACROSS THE EASTERN U.S. MONDAY. A
SHORTWAVE IN THE MIDWEST WILL ROUND THE BASE OF THE UPPER TROUGH AND
RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS MONDAY AFTERNOON.
RAISED HIGH TEMPERATURES UP A FEW DEGREES ON MONDAY WITH VALUES FROM
THE LOWER 70S IN THE MOUNTAINS TO AROUND 80 DEGREES IN THE PIEDMONT.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 400 PM EDT SUNDAY...
AMPLIFIED UPPER LEVEL TROUGH OVER THE EASTERN CONUS WILL BE THE
DOMINANT WEATHER FEATURE EARLY IN THE PERIOD...THEN WEAKEN MID WEEK
AS HEIGHTS GRADUALLY RISE. ATTENDANT SURFACE FRONT/BAROCLINIC ZONE
WILL REMAIN CONFINED TO OUR SOUTH...DEEPER MOISTURE MAINLY CONFINED
TO THE COASTAL REGIONS OF THE GULF COAST AND SOUTHEAST ATLANTIC
TIDEWATER. IN SPITE OF THIS MOISTURE LIMITATION...SHORT WAVE ENERGY
IS PROGGED TO SPIRAL AROUND THE UPPER TROUGH...SUBJECTING OUR FCST
AREA TO PERIODS OF CLOUD COVER AND SCATTERED SHOWERS. CONFLICTING
SIGNALS EXIST IN THE TIMING OF THE INDIVIDUAL SHORTWAVES...BUT THE
MODELS DO AGREE ON THE LARGER SCALE FEATURES. THAT SAID WILL BROAD
BRUSH POPS BOTH TUESDAY AND WEDNESDAY TO ACCOUNT FOR SHORT WAVE
TIMING UNCERTAINTIES...BUT SIDE WITH THE COOLER MODEL GUIDANCE PER
THE PERSISTENCE OF THE COOLER UPPER LEVEL TROUGH.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 400 PM EDT SUNDAY...
MODEL SOLUTIONS MIXED FOR THE LATTER HALF OF THE WEEK WITH GREATEST
ENSEMBLE SPREAD NEXT WEEKEND. THE GENERAL IDEA HOWEVER SEEMS TO BE A
WEAK MEAN TROF OVER THE ERN CONUS...IN SPITE OF ITS WEAKENING
EARLIER IN THE WEEK. THIS SUGGESTS ANY SHORTWAVE ENERGY WHICH
ARRIVES FROM SYSTEMS PASSING THROUGH SRN CANADA AND THE NRN CONUS
WILL HAVE A CHANCE TO AMPLIFY AS THEY PROGRESS EAST BOUND INTO THE
UPPER LEVEL TROF. THIS IMPLIES WEATHER ACROSS OUR REGION WILL
REMAIN ACTIVE WITH AT LEAST CHC SHRA/TSRA DURING THE PERIOD...MAINLY
DIURNALLY DRIVEN THURSDAY AND FRIDAY...BUT POTENTIALLY MORE
WIDESPREAD FOR NEXT WEEKEND PENDING AMPLIFICATION OF ANY OF THE
SHORTWAVES THAT MOVE DOWNSTREAM FROM THE UPPER MID WEST.
WITH WEAKENING OF THE EASTERN TROF...TRENDED TEMPERATURES UPWARD
CLOSER TO THE SEASONAL NORMS.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 800 PM EDT SUNDAY...
LOW CEILINGS WILL PROMOTE MVFR CONDITIONS FOR THE EARLY PART OF THE
EVENING. PLENTY OF RAIN FELL ACROSS THE REGION ON SUNDAY. THIS ALONG
WITH AN ABUNDANCE OF LOW LEVEL MOISTURE AND LIGHT SURFACE WINDS WILL
ALLOW FOG TO SET UP OVERNIGHT. IFR/LIFR CONDITIONS EXPECTED FROM
AROUND 06Z UNTIL AS LATE AS 14Z WHEN DAYTIME HEATING CAN BEGIN TO
ERODE THE FOG. VFR/MVFR CONDITIONS ARE EXPECTED BEYOND 14Z. WINDS
WILL CONTINUE TO HAVE AN EASTERLY COMPONENT BEFORE SWITCHING TO THE
W/NW LATE MONDAY MORNING AS ANOTHER DISTURBANCE APPROACHES. THIS
DISTURBANCE WILL KEEP A CHANCE OF SCATTERED SHOWERS AND
THUNDERSTORMS IN THE FORECAST DURING THE AFTERNOON AND EARLY EVENING
HOURS...HOWEVER AT THIS POINT HAVE KEPT PCPN OUT OF THE TAF
LOCATIONS.
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ON TUESDAY...ISOLATED
AND BRIEF MVFR/IFR CONDITIONS ARE POSSIBLE. BY WEDNESDAY THE COLD
FRONT CONTINUES TO MOVE FURTHER TO OUR EAST. HIGH PRESSURE WILL
THEN BUILD IN FOR THE REMAINDER OF THE PERIOD...WITH MAINLY
VFR/MVFR CONDITIONS EXPECTED.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...KK
NEAR TERM...KK/SK/WERT
SHORT TERM...PM
LONG TERM...PM
AVIATION...CF
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
325 AM CDT MON AUG 20 2012
.SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM TO HIGH.
VALLEY FOG DEVELOP EARLY THIS MORNING WITH LIGHT WINDS AND CLEAR
SKIES...ESPECIALLY IN AREAS THAT RECEIVED PRECIPITATION. DENSE FOG
EXPECTED IN THE WISCONSIN RIVER VALLEY.
ISOLATED SHOWERS ARE EXPECTED MONDAY AFTERNOON IN THE EASTERN
COUNTIES. ONSHORE WINDS WITH HIGHER DEWPOINTS BRING WEAK INSTABILITY
HERE...AND COMBINE WITH APPROACHING SHORTWAVE TROUGH AND COLD MID
LEVELS TO BRING MEDIUM. ZERO TO 1 KM CAPE VALUES AROUND 4500 J/KG
OVER PORTIONS OF SOUTHEAST WISCONSIN.
4 KM HRRR DEVELOP AN AREA OF SHOWERS/THUNDERSTORMS LATE MORNING AND
AFTERNOON OVER THE LAKE SHORE AREA THAT PUSHES INLAND WITH LAKE
BREEZE. NON SUPERCELL INDEX VALUES RISE TO AROUND 2 TO 3...BUT
FORECAST SOUNDINGS HAVE ENOUGH MID LEVEL DRY AIR WITH LAPSE RATES
AROUND 8.8 C/KM AT 850 MB. SURFACE CONVERGENCE IS VERY WEAK AND 700
MB UPWARD MOTION IS WEAK.
EXPECT SOME PATCHY FOG AGAIN LATE TONIGHT...ESPECIALLY IN THE
WISCONSIN RIVER VALLEY.
TUESDAY AND TUESDAY NIGHT...FORECAST CONFIDENCE IS HIGH.
BEAUTIFUL DAY IN STORE FOR TUESDAY. HIGH PRESSURE WILL GRADUALLY
SHIFT EASTWARD. SUBSIDENCE BEHIND DEPARTING UPPER TROUGH WILL ALLOW
FOR ONLY A FEW CUMULUS CLOUDS IN THE AFTERNOON. LAKE BREEZE EXPECTED
WITH THE WEAK SURFACE GRADIENT. 925MB TEMPS WILL BE INCREASING
TOWARD 20C...YIELDING MAX TEMPS AROUND 80F.
WEDNESDAY THROUGH THURSDAY...FORECAST CONFIDENCE IS MEDIUM TO HIGH.
WEDNESDAY LOOKS LIKE IT WILL BE ANOTHER NICE DAY. THERE COULD BE
SOME HIGH-BASED SHOWERS THAT MAY OR MAY NOT REACH THE GROUND
WEDNESDAY NIGHT. THEN THURSDAY LOOKS LIKE IT WILL BE QUITE WARM IN
THE WARM SECTOR AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM.
THE NOSE OF THE LOW LEVEL JET IS FORECAST TO BE IN SOUTHEAST MN ON
MOST MODELS...EXCEPT THE NAM REACHES INTO FAR WESTERN WI BY WED
AFTERNOON. THE NAM AND GFS ARE MOST ROBUST WITH SHOWER POTENTIAL
OVER SOUTHERN WI WED NIGHT WITH THE WARM AIR ADVECTION AND A WEAK
SHORTWAVE...AND THE NHEM CANADIAN MODEL EVEN SHOWS LIGHT QPF IN THE
AREA...BUT THE ECMWF KEEPS IT DRY. FOR NOW...CONTINUED WITH THE DRY
FORECAST FOR WED AND WED NIGHT.
BY THURSDAY THE LOW LEVEL JET PUSHES INTO NORTHERN MN AND NORTHERN
WI...FOCUSING ANY WARM AIR ADVECTION CONVECTION WELL TO THE NORTH OF
OUR FORECAST AREA. THEREFORE...CONTINUED WITH THE DRY FORECAST.
THE WARMEST AIR IS EXPECTED TO PUSH INTO SOUTHERN WI BY THU
AFTERNOON...WITH 925MB TEMPS REACHING 25 TO 26C ON THE ECMWF. THE
NAM SHOWS CHARACTERISTICALLY HIGHER 925MB TEMPS SO IGNORED FOR NOW.
BUMPED UP THE MAX TEMPS FOR WED AND THU...WITH THU LIKELY REACHING
THE UPPER 80S TO POSSIBLY 90.
.LONG TERM...
THURSDAY NIGHT THROUGH MONDAY...FORECAST CONFIDENCE IS LOW.
A 500MB TROUGH WILL SWING ACROSS THE UPPER MIDWEST EARLY IN THE
WEEKEND. THE GFS IS FASTEST WITH BRINGING SHOWERS AND THUNDERSTORMS
WITH A COLD FRONT INTO SOUTHERN WI THU NIGHT...WITH THE ECWMF MUCH
SLOWER. IN GENERAL...THIS FRONT WOULD BRING A ROUND OF TSTORMS
ACROSS SOUTHERN WI SOMETIME BETWEEN LATE THU NIGHT AND FRI
NIGHT...OR NOT AT ALL ACCORDING TO THE CANADIAN MODEL.
THE MAJOR UNCERTAINTY WILL BE PRECIP CHANCES FOLLOWING THAT INITIAL
FRONT...WHICH WILL DEPEND ON HOW THE MODELS HANDLE THE TIME BETWEEN
THE AFOREMENTIONED UPPER TROUGH AND THE NEXT UPPER TROUGH MOVING
THROUGH THE REGION SUNDAY THROUGH MONDAY. THE GFS MOVES A STRONG
SHORTWAVE INTO SOUTHERN WI FROM THE SOUTH SAT NIGHT AND THE ECMWF
AND CANADIAN MODELS JUST WAIT FOR THE SECOND TROUGH TO MOVE THROUGH
TO GENERATE MORE STORMS.
BOTTOM LINE IS THERE WILL BE TWO OR MAYBE 3 ROUNDS OF SHOWERS AND
THUNDERSTORMS BETWEEN LATE THU NIGHT AND MONDAY AFTERNOON BUT WE
JUST DO NOT KNOW WHEN.
&&
.AVIATION/12Z TAFS/...
LIGHT WINDS AND MOSTLY CLEAR SKIES SHOULD ALLOW FOR IFR/PATCHY LIFR
FOG POSSIBILITIES MAINLY IN LOW AREAS THAT RECEIVED PRECIPITATION
YESTERDAY. ALSO EXPECT LIFR FOG IN THE WISCONSIN RIVER VALLEY.
MORE SCATTERED TO BROKEN DIURNAL CUMULUS CLOUDS ARE EXPECTED TO
DEVELOP MONDAY AFTERNOON WITH CLOUD BASES AROUND 4-5 THSD FT.
ALSO EXPECT SCATTERED SHOWERS MAINLY OVER SOUTHEAST WISCONSIN BY
AROUND NOON AND THROUGH THE AFTERNOON. MVFR CIGS/IFR VSBYS IN THE
HEAVER SHOWERS AND THUNDERSTORMS. DRIER AIR OVER SOUTH CENTRAL AND
NORTHWEST PORTIONS OF SOUTHEAST WISCONSIN WITH LESS OF A SHOWER
POSSIBILITY.
SIMILAR FOG SITUATION FOR LATE TONIGHT.
&&
.MARINE...
4 KM HRRR AND LOCAL WRF HAS LOW LEVEL CYCLONIC CIRCULATION OVER FAR
SOUTHERN LAKE MICHIGAN. A FEW SHOWERS OVER THE ILLINOIS WATERS.
THEREFORE THREAT OF WATERSPOUTS LOW OVER OUR FORECAST AREA. HOWEVER
MODELS DEVELOP AN AREA OF SHOWERS/THUNDERSTORMS LATE MORNING AND
AFTERNOON OVER THE LAKE SHORE AREA THAT PUSHES INLAND WITH LAKE
BREEZE. ANY WATERSPOUT THREAT WOULD LIKELY OCCUR AS THESE SHOWERS
FORM.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
TUESDAY THROUGH SUNDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1140 PM CDT SUN AUG 19 2012
.SHORT TERM...THROUGH TUESDAY NIGHT
246 PM CDT SUN AUG 19 2012
SURFACE ANALYSIS THIS AFTERNOON SHOWS A WEAK COLD FRONT EXTENDING
ACROSS CENTRAL WISCONSIN INTO WESTERN MINNESOTA. HIGH PRESSURE WAS
CENTERED OVER NORTHERN NORTH DAKOTA.
LOCAL AND REGIONAL RADARS ARE SHOWING A FEW SHOWERS DEVELOPING
ALONG AND AHEAD OF THE FRONT ACROSS WISCONSIN INTO EASTERN
MINNESOTA. MU CAPES AROUND A 1000 J/KG ARE IN PLACE AHEAD OF THE
FRONT BUT WITH A WEAK WIND FIELD...THE CONVERGENCE ALONG THE FRONT
IS NOT VERY STRONG. A WEAK SHORT WAVE TROUGH WAS PROVIDING ENOUGH
LIFT TO AID THE DEVELOPMENT OF THE SHOWERS. THIS WAVE WILL SLIP
SOUTH OF THE AREA THIS EVENING TAKING THE FORCING WITH IT. SOME
CONCERN THAT ADDITIONAL WAVES UP STREAM IN THE FLOW ALOFT COULD
CONTINUE TO PROVIDE SOME WEAK FORCING THROUGH THE NIGHT.
HOWEVER...ONCE THE FRONT GOES THROUGH DEW POINTS ARE EXPECTED TO
FALL INTO THE 40S. THIS ALONG WITH THE LOSS OF HEATING...SHOULD BE
SUFFICIENT TO LOWER CAPE AND ALLOW THE SHOWERS TO DISSIPATE. WILL
CARRY A SMALL RAIN CHANCE ACROSS THE SOUTHERN HALF OF THE AREA INTO
THE EVENING TO COVER THE DISSIPATING EVENING SHOWERS.
ONCE THE SHOWERS ARE DONE...THE SKIES SHOULD CLEAR OUT AND WITH
THE HIGH BUILDING IN...THE CONCERN BECOMES WHETHER VALLEY FOG WILL
FORM. ONCE AGAIN...THIS DOES NOT LOOK TO BE A CLEAR CUT EVENT. THE
WINDS AT THE SURFACE ARE EXPECTED TO DECOUPLE AND WITH THE CLEAR
SKIES...GOOD RADIATIONAL COOLING SHOULD OCCUR. HOWEVER...THE
FORECAST SOUNDINGS FROM BOTH THE 19.12Z NAM AND 19.17Z RAP SUGGEST
THE WINDS JUST ABOVE THE SURFACE UP THROUGH AT LEAST 5K FEET
SHOULD BE AROUND 10 KNOTS...BUT DECREASING TOWARD 12Z MONDAY.
ALSO...THE NAM SUGGESTS THAT SATURATION SHOULD ONLY OCCUR AT THE
SURFACE WITH DRIER AIR ABOVE WITH THE STRONGER WINDS. WOULD EXPECT
SOME FOG TO BE AROUND BUT WOULD NOT EXPECT THE WHOLE VALLEY TO
FILL IN AND WILL MAINTAIN THE MENTION OF AREAS OF VALLEY FOG. THE
HIGH WILL THEN DRIFT SOUTHEAST ACROSS THE AREA AND PROVIDE QUIET
WEATHER INTO TUESDAY NIGHT.
.LONG TERM...WEDNESDAY THROUGH SUNDAY
246 PM CDT SUN AUG 19 2012
MODELS IN THIS TIME FRAME HAVE BEEN SHOWING SOME INCONSISTENCIES
ON HOW THE PATTERN WILL EVOLVE AS ENERGY COMES OUT OF THE MEAN
LONG WAVE TROUGH ALONG THE WEST COAST. THE LATEST MODELS RUNS
STILL SHOW A SHORT WAVE TROUGH COMING OUT OF THE WEST COAST SYSTEM
STARTING WEDNESDAY. HOWEVER...NOW INSTEAD OF BUILDING INTO THE
UPPER MIDWEST...THE UPPER LEVEL LOW MOVES NORTHEAST TOWARD CENTRAL
CANADA BRINGING THE SHORT WAVE TROUGH THROUGH THE AREA WITH A
POSITIVE TILT THURSDAY NIGHT THROUGH FRIDAY NIGHT. AS THIS IS
HAPPENING...THE UPPER LEVEL THAT HAD BEEN OFF THE WEST COAST IS
SHOWN TO START MOVING EAST ACROSS SOUTHERN CANADA IMPACTING THE
UPPER MIDWEST OVER THE WEEKEND. AT THE SURFACE...THE 19.12Z GFS
REMAINS STRONGER WITH THE LEAD SYSTEM THAN THE 19.00Z ECMWF
SHOWING A LOW ALONG THE CANADIAN BORDER WITH A COLD FRONT COMING
INTO THE AREA. MEANWHILE...THE ECMWF CONTINUES TO JUST SHOW A WEAK
SURFACE LOW DRIFTING ACROSS THE UPPER MIDWEST. BOTH MODELS THEN
SHOW A LOW MOVING ACROSS CANADA WITH ANOTHER COLD FRONT OVER THE
UPPER MIDWEST WITH THE MAIN UPPER LEVEL LOW...BUT DIFFER ON THE
TIMING WITH THE GFS BEING THE QUICKEST. IN GENERAL...WILL CARRY 30
TO 40 PERCENT RAIN CHANCES STARTING THURSDAY NIGHT THROUGH THE
WEEKEND AND WAIT FOR LATER MODEL RUNS AND HOPEFULLY BETTER
AGREEMENT TO MAKE REFINEMENTS.
&&
.AVIATION...THROUGH 06Z TUESDAY
1140 PM CDT SUN AUG 19 2012
THE MAIN FOCUS OVERNIGHT IS WITH THE POTENTIAL FOR VALLEY FOG AT
LSE. QUITE A FEW FACTORS IN FAVOR OF THE DEVELOPMENT WITH CLEAR
SKIES...LIGHT SURFACE WINDS...RAINFALL IN THE PAST 24 HORUS...3Z
DEW POINT DEPRESSION OF ONLY 4F...AND MINIMUM TEMPERATURES THAT
DROP A FEW DEGREES BELOW THE CROSSOVER TEMPERATURE. THE MAIN
LIMITING FACTORS ARE WITH 10-15KT WINDS JUST ABOVE THE INVERSION
AROUND 0.5KM AND THE POSSIBLE ADVECTION OF DRIER SURFACE AIR IN
FROM THE NORTH. IT SEEMS THAT THERE IS MORE WORKING FOR THE
DEVELOPMENT OF THE VALLEY FOG AS WELL AS IN THE HIGHER TERRAIN
NEAR RST. SO...HAVE BROUGHT CONDITIONS DOWN AROUND 9/10Z WITH LSE
LIKELY GETTING TO 1/2SM OR LOWER AT TIMES. AT RST...THE VISIBILITY
IS NOT EXPECTED TO DROP AS LOW...BUT IF SOME SHALLOW GROUND FOG
CAN FORM THEN IT MAY.
AFTER THE FOG LIFTS AROUND 13/14Z...WINDS WILL REMAIN LIGHT
THROUGH THE REST OF THE DAY WITH SOME FAIR WEATHER CU DEVELOPING
LATE IN THE MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
246 PM CDT SUN AUG 19 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1104 AM EDT MON AUG 20 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 140 AM EDT MON AUG 20 2012
A WEAK FRONT OVER CENTRAL INDIANA TODAY WILL BE SHOVED AWAY TUESDAY
BY HIGH PRESSURE COMING FROM THE WEST. THE HIGH PRESSURE IS
FORECAST TO REACH THE EAST COAST WEDNESDAY. IT IS LIKELY TO STALL
THERE AND STAY IN CONTROL OF HOOSIER WEATHER INTO NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1104 AM EDT MON AUG 20 2012
GOING FORECAST REQUIRED ONLY MINOR TWEAKS TO INCORPORATE LATEST
OBSERVATIONAL TRENDS. DID SWITCH FROM SLIGHT CHANCE/CHANCE WORDING
TO ISOLATED THUNDERSTORMS...FELT THIS BEST DESCRIBED THE SITUATION
THIS AFTERNOON.
CLEAR SKIES SHOULD RULE UNTIL AROUND 1 PM/17Z...WHEN RAP SOUNDINGS
SUGGEST CONVECTIVE TEMPERATURES WILL BE MET AND CU WILL START TO
FORM. ASIDE FROM LOW LEVEL MOISTURE BEING SLIGHTLY
BETTER...AIRMASS HAS CHANGED LITTLE APPRECIABLY FROM SUNDAY...AND
EXPECT SIMILAR EVOLUTION TO PLAY OUT. SHOULD SEE SKIES BECOME
PARTLY CLOUDY WITH A FEW THUNDERSTORMS MANAGING TO POP. WEAK
CONVERGENCE ZONE OVER NW INDIANA/NE ILLINOIS SUGGESTS INITIAL
DEVELOPMENT MAY OCCUR THERE AS WEAK SHORTWAVE OVER WISCONSIN
CONTINUES SOUTHERN PROGRESS.
TEMPS GENERALLY RUNNING 2 DEGREES ABOVE PERSISTENCE ACROSS MUCH OF
THE AREA...ESPECIALLY CENTRAL AND SOUTH. ADJUSTED HIGH TEMPS
SLIGHTLY TO REFLECT THIS. SHOULD GET INTO THE UPPER 70S
NORTH...AROUND 80 IN THE INDY METRO...WITH LOW TO MID 80S
SOUTH/SOUTHWEST.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 140 AM EDT MON AUG 20 2012
FORECAST PROBLEM IS POPS. VARIOUS GUIDANCE TYPES DONT AGREE WELL
THROUGH TUESDAY. THEY DO CONCUR DRY STARTING TUESDAY NIGHT.
AS WITH YESTERDAY...GFS CLOSER TO MODEL CONSENSUS THAN NAM...BUT ITS
DEWPOINTS LOOK TOO HIGH. IN PACKAGE ISSUED YESTERDAY MORNING USING
WHATEVER GUIDANCE HAD THE LOWEST POPS WORKED OK. WILL TRY THAT
AGAIN...WHICH MEANS A DRY FORECAST. ALL MODELS AT LEAST AGREE PARTLY
CLOUDY IN ORDER AS WEAK SHORT WAVES PASS IN NORTHWEST FLOW ALOFT.
TEMPS...MAV MET CONSENSUS. THIS CONTINUES THEME OF WHAT HAS WORKED
WELL LATELY SHOULD CONTINUE TO WORK WELL IN SIMILAR SITUATION.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ISSUED AT 255 AM EDT MON AUG 20 2012
ZONAL FLOW APPEARS ALOFT DURING THIS PERIOD WITH MINIMAL DYNAMICS
PUSHING ACROSS INDIANA. HIGH PRESSURE IN PLACE AT THE SURFACE EAST
OF INDIANA WILL PROVIDE WARMER TEMPERATURES EACH DAY THROUGH
SUNDAY ALONG WITH INCREASING DEW POINTS. BY SATURDAY AFTERNOON AND
SUNDAY...ENOUGH HEAT AND MOISTURE SHOULD BE IN PLACE TO ALLOW FOR
SCT DIURNAL SHRA OR TSRA. ECMWF AND GFS BOTH INDICATE FAVORABLE
LOWER LEVEL FLOW WITH GULF MOISTURE ARRIVING ON SOUTHERLY WINDS.
MORE ORGANIZED PRECIP APPEARS TO REACH THE AREA ON MONDAY AS THE
GFS AND ECMWF SUGGEST A COLD FRONT MARCHING ACROSS THE AREA WITH A
WARM AND MOIST AIR MASS IN PLACE AHEAD OF THE FRONT ACROSS
INDIANA.
&&
.AVIATION /DISCUSSION FOR THE 201500Z TAF UPDATES/...
ISSUED AT 1025 AM EDT MON AUG 20 2012
ONLY MADE MINOR TWEAKS TO THE WINDS. OTHERWISE...NO CHANGES.
PREVIOUS DISCUSSION FOLLOWS...
VFR CONDITIONS EXPECTED THIS TAF PERIOD.
AN UPPER SHORT WAVE WILL PUSH ACROSS INDIANA THIS AFTERNOON AND
TONIGHT. MOISTURE REMAINS SUSPECT. FORECAST SOUNDINGS INDICATE
FAVORABLE LAPSE RATES FOR CU AND CONVECTION THIS AFTERNOON AS
CONVECTIVE TEMPS IN THE MID AND UPPER 70S SHOULD BE EASILY
REACHED. CONFIDENCE FOR PRECISE TIMING OF TSRA TOO LOW AND WILL
USE VCTS DURING THE PEAK HEATING HOURS THIS AFTERNOON.
WITH THE LOSS OF HEATING TSRA CHANCES WILL DIMINISH THIS
EVENING...HOWEVER AS THE SHORT WAVE PASSES OVERNIGHT A FEW
LINGERING CLOUDS WILL REMAIN POSSIBLE...HOWEVER VFR CONDITIONS
WILL REMAIN DURING THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...NIELD
SHORT TERM...JK
LONG TERM....PUMA
AVIATION...JP/MK
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1112 AM EDT MON AUG 20 2012
.SYNOPSIS...
ISSUED AT 400 AM EDT MON AUG 20 2012
HIGH PRESSURE WILL BUILD INTO THE GREAT LAKES TODAY. AS THIS HIGH
SLIDES TO THE MID-ATLANTIC STATES WEDNESDAY AND THURSDAY...WINDS
WILL SHIFT TO THE SOUTHWEST...BRINGING WARMER TEMPERATURES TO THE
REGION. A WEAK COOL FRONT WILL TRY TO EASE IN THURSDAY AND
FRIDAY...WHICH MAY TRIGGER A SHOWER OR THUNDERSTORM LATE NEXT
WEEK...INTO NEXT WEEKEND. HOWEVER...THE WEATHER WILL BE DRY AND FAIR
MOST OF THE TIME.
&&
.UPDATE...
ISSUED AT 1112 AM EDT MON AUG 20 2012
A TROPOPAUSE PV ANOMALY IS OVER WI WITH ITS RELATED SFC TROF
SINKING SEWD ACROSS ERN LAKE SUPERIOR INTO THE CNTRL U.P. A
MODEST 60 KT JET STREAK IS ASSOCIATED WITH THE PV ANOMALY. IT
REMAINS COOL ALOFT WITH H5 TEMPS -18C THIS MRNG. WE`RE ALREADY
NOTING AN INCREASE IN SHWR ACTIVITY ON LAKE SUP FROM NEAR CARIBOU
ISLAND DOWN TO PARADISE. THIS LINES UP WELL WITH SPC WRF-NMM AND
THE RAP ENSEMBLE PROBS FOR .01" QPF. POPS WERE UPGRADED WITH THIS
UPDATE WITH ADDITIONAL INCORPORATION OF THIS GUIDANCE FOR THIS
AFTN. WE`VE NOW MENTIONED POTENTIAL FOR SCT SHWRS OVER THE ERN
U.P. AND THE POTENTIAL FOR A SHWR OR TWO NEAR M-72 AND OVER NE
LOWER E OF I-75. DESPITE COOL AIR ALOFT...LAPSE RATES AND MSTR ARE
UNIMPRESSIVE. HOWEVER...THE NAM/GFS DEPICT A POOL OF H85 MSTR OVER
LAKE SUP...NOT SAMPLED BY THE 12Z GRB/APX SOUNDINGS. SO LOW-LVL
MOISTENING WILL INCREASE POTENTIAL A TAD FOR FAIRLY HIGH-BASED
SHWRS. THUNDER? PROBABLY NOT GIVEN MINIMAL INSTABILITY.
UPDATE ISSUED AT 910 AM EDT MON AUG 20 2012
RADAR IS NOW IN VCP 221 FOR MORE RAPID UPDATES AND ENHANCED
VELOCITY DETECTION TO MONITOR BUILDING CU OVER NRN LAKE MI. THE
FCST NOW HAS SLGT CHANCE OF SHWRS FROM LAKE MI INTO THE IMMEDIATE
COAST OF NW LOWER MI...AND A SLGT CHANCE OF WATERSPOUTS OVER THE
NEARSHORE WATERS.
UPDATE ISSUED AT 840 AM EDT MON AUG 20 2012
A QUICK UPDATE HAS BEEN PUBLISHED FOR THE SHWR THAT`S MOVING THRU
PETOSKEY. ALSO INCREASED SKY TO P/CLOUDY OVER FAR NE LWR MI. WE`RE
WATCHING THE LAND BREEZE BOUNDARIES OVER NRN LAKE MI. IF SHWRS
FORM...WE`LL BE ISSUING AN SMW FOR WATERSPOUTS.
UPDATE ISSUED AT 624 AM EDT MON AUG 20 2012
NO UPDATES NEEDED THIS MORNING...STILL BATTLING PESKY MID/UPPER
LEVEL CLOUDS ACROSS THE NRN HALF OF THE CWA. OTHERWISE...JUST SOME
PATCHY FOG IN LOW LYING AREAS. INTERESTINGLY...THERE ARE IN FACT
SOME UPPER 30S TEMPERATURES OUT THERE...WITH GRAYLING COMING IN AT
38 DEGREES....ATLANTA 36 DEGREES AND JUST SOUTH OF US...LEOTA ALSO
AT 36 DEGREES. QUITE THE CHILLY START TO WHAT WILL BE ANOTHER
BEAUTIFUL NRN MICHIGAN SUMMER DAY.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 400 AM EDT MON AUG 20 2012
CLOSED UPPER LOW IS FINALLY STARTING TO MOVE EAST OF JAMES BAY
THIS MORNING...WHILE YET ANOTHER WEAK SFC TROUGH IS SINKING DOWN
THROUGH LAKE SUPERIOR. THERE ARE EMBEDDED SHORTWAVES THAT ARE
ROTATING AROUND THE BACKSIDE OF THE UPPER LOW...AND INTO THE GREAT
LAKES REGION. NONE OF THESE WAVES ARE PRODUCING ANY SIGNIFICANT
FORCING ALOFT. HOWEVER...THERE IS A BAND OF HIGHER LEVEL CLOUDS
DROPPING THROUGH NRN LOWER. TEMPERATURES HAVE PLUMMETED INTO THE
LOWER 40S...AND THERE ARE LIKELY SOME LOCALIZES SPOTS IN THE UPPER
30S. TEMPERATURES WERE AS MILD AS THE MIDDLE 50S NEAR THE WARMER
GREAT LAKES.
TODAY...MOST AREAS WILL BE ABLE TO START OFF WITH DECENT SUNSHINE
THIS MORNING...AND THE CHILLY TEMPERATURES WILL SPIKE UP RATHER
QUICKLY. WINDS WILL OVERALL BE OUT OF THE WEST AND NORTHWEST...BUT
BEING RELATIVELY LIGHT...LAKE BREEZES ARE EXPECTED TO ONCE AGAIN
FIRE OFF THIS AFTERNOON...AND MAKE IT ALL THE WAY INTO THE
INTERIOR HIGHER TERRAIN OF NRN LOWER. THERE WILL BE A BIT MORE OF
A WESTERLY BREEZE ACROSS EASTERN UPPER AHEAD OF THE SFC TROUGH
WHICH WILL SETTLE INTO THIS AREA. HOWEVER...THE TAIL END OF THE
TROUGH WILL BECOME MORE UNDEFINED WITH TIME AS IT WASHES OUT WITH
THE EASTWARD TREK OF THE UPPER LOW. THEREFORE...EVEN THESE WINDS
ARE EXPECTED TO LOOK MORE LIKE LAKE BREEZES THIS AFTERNOON. THESE
TWO CONVERGENCE AREAS WILL BE THE FOCUS FOR ANY PRECIPITATION THAT
TRIED TO GENERATE TODAY. ONE SHORTWAVE THAT IS DROPPING DUE SOUTH
THROUGH WESTERN ONTARIO ATTM...WILL SHARPEN UP WHAT WILL
ULTIMATELY BE THE FINAL MID LEVEL TROUGH AXIS TO ROLL THROUGH.
THIS MID LEVEL TROUGH...COUPLED WITH THE SFC TROUGH/LAKE BREEZE
CONVERGENCE IN EASTERN UPPER...WILL RESULT IN A SLIGHT CHANCE OF
SHOWERS IN EASTERN UPPER. THE AIR MASS IS NOT OVERLY MOIST PER
LATEST APX SOUNDINGS...HOWEVER THERE WAS AN ISOLATED SHOWER THAT
FIRED UP ON THE LAKE BREEZE LATE IN THE DAY YESTERDAY IN NE LOWER.
DON`T SEE WHY THIS COULDN`T HAPPEN IN EASTERN UPPER TODAY...SINCE
THE SYNOPTIC SETUP IS THERE.
WHATEVER DOES DEVELOP LATE THIS AFTERNOON...WON`T LAST LONG. LOSS
OF HEATING AND DEPARTURE OF SAID SHORTWAVE/MID LEVEL TROUGH AXIS
WILL LIKELY NOT PRODUCE ANYTHING AFTER 9PM...BUT NW MID LEVEL
STEERING FLOW COULD SEND A SHOWER OUT OVER THE STRAITS/NRN LAKES
MICHIGAN AND HURON. AFTER THIS...MID LEVEL HEIGHT RISES AND MORE
INFLUENCE FROM THE HIGH PRESSURE TO THE WEST WILL RESULT IN
GRADUALLY CLEARING SKIES OVERNIGHT. TEMPERATURES WILL BE ABLE TO
FALL INTO READINGS SIMILAR TO THIS MORNING...AS WE REMAIN IN THE
LOW LEVEL COOL POOL THROUGH DAYBREAK WITH LIGHT WINDS. SO..EXPECT
ANOTHER CHILLY ONE WITH MAYBE SOME PATCHY FOG IN THE LOWEST OF
AREAS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 400 AM EDT MON AUG 20 2012
TUESDAY...THE 500 MB WAVE CONTINUES TO MOVE THROUGH THE FLOW, AND
WITH RIDGE TO THE WEST FORCING THE HEIGHTS TO CONTINUE TO RISE,
CLOUDS MOVE INTO E UPPER, HOWEVER, THE MODELS SEEM TO INDICATE THAT
THE RAIN SHOULD REMAIN IN ONTARIO NORTH OF THE SOO, JUST BASED ON
THE 700-500 MB LAYER RH AND THE 850 MB RH FIELDS.
TUESDAY NIGHT...THE MODELS CONTINUE TO KEEP THIS SYSTEM NORTH OF THE
SOO AND IN N LAKE SUPERIOR. ALTHOUGH NOW THE GFS IS BRINGING IT
CLOSER TO E UPPER. HOWEVER, IT LOOKS LIKE NAM/ECMWF SOLUTION LOOKS
MORE REASONABLE WITH THE MOISTURE IN THE 700-500MB LAYER A LITTLE
MORE NORTH THAN THE GFS, WHICH HAS BEEN THE TREND OVER THE LAST
SEVERAL RUNS.
WEDNESDAY...WITH THE SFC HIGH MOVES EAST, AND THE COLD FRONT BEGINS
TO PUSH SOUTH WITH SOME WEAK REINFORCEMENT FROM THE 500 MB LOW TO
THE NORTH. SO WILL HAVE SOME WEAK CHANCE POPS IN E UPPER NEAR THE
BOUNDARY AND WAVE. THE MOISTURE THINS QUITE A BIT OVERNIGHT, SO
WON`T BE SURPRISED IF THIS IS JUST A FIGMENT OF THE MODELS
IMAGINATION.
EXTENDED (THURSDAY THROUGH SUNDAY)...THURSDAY, THE FRONT SAGS INTO N
LOWER SO THE WEAK CHANCES FOR RAIN SHOWERS AND IS OVER THE FORECAST
AREA, ESPECIALLY NE LOWER WHERE IT IS CLOSER TO THE 500 MB LOW. HIGH
PRESSURE BUILDS INTO THE REGION OVERNIGHT. HOWEVER, THE MAIN ACTION
LOOKS LIKE IT WON`T ARRIVE UNTIL FRIDAY. THE NEXT SYSTEM ON FRIDAY
MOVES OUT OF THE PLAINS AND INTO THE WESTERN GREAT LAKES. WITH THE
STALLED BOUNDARY, AND SOME MOISTURE AT 850 MB (AT LEAST ON THE
ECMWF) THUNDERSTORM BECOME A POSSIBILITY DURING THE DAY, AND A
BETTER ONE AT NIGHT. THE GFS REALLY DEVELOPS THE SFC FEATURE NORTH
OF LAKE SUPERIOR, SO THINK THAT THERE IS SOME FEEDBACK ISSUES, AND
THAT THE ECMWF LOOKS MORE REALISTIC. SATURDAY, MODELS ARE SHOWING
SOME DIFFERING OPINIONS ON THE WAY THIS SYSTEM WILL EVOLVE. THE 00Z
ECMWF HAS BACKED OFF THE FROPA UNTIL SUNDAY, AND PROBABLY WILL BE
MORE A MONDAY THING. IT IS LOOKING LIKE SOME TROPICAL SYSTEM IS
AFFECTING THE SPEED OF THE FRONT. SO WILL LEAVE THE DAY AND NIGHT
WITH CHANCES. SUNDAY, MODELS BOTH HAVE THE FRONT TRYING TO MOVE INTO
THE FORECAST AREA, OR ALREADY HAVE MOVED INTO THE REGION. WILL
CONTINUE SOME SORT OF CHANCES, BUT IF THERE IS A TROPICAL SYSTEM
MOVING INTO THE GULF COAST AS HINTED BY BOTH, THIS MAY BE ENOUGH TO
DELAY THE RAIN AND FROPA FOR ANOTHER DAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 624 AM EDT MON AUG 20 2012
A SFC TROUGH WILL SETTLE INTO EASTERN UPPER THIS AFTERNOON...WHILE
NRN MICHIGAN WILL SLOWLY BECOME MORE UNDER THE INFLUENCE OF HIGH
PRESSURE PRESSING EAST FROM THE MISSISSIPPI VALLEY. NORTHWESTERLY
GRADIENT WINDS WILL BE LIGHT ENOUGH FOR LAKE BREEZES THIS
AFTERNOON...BEFORE GOING CALM AGAIN TONIGHT WITH SOME PATCHY LATE
NIGHT LOWLAND FOG. SCATTERED TO BROKEN VFR CUMULUS EXPECTED TODAY
WITH NO PRECIP CONCERNS FOR THE AIRPORTS.
&&
.MARINE...
ISSUED AT 400 AM EDT MON AUG 20 2012
HIGH PRESSURE WILL WORK ACROSS THE MISSISSIPPI VALLEY AND INTO THE
SRN GREAT LAKES/OHIO VALLEY REGION OVER THE NEXT FEW DAYS. WINDS
WILL BE SUB-ADVISORY THROUGH TUESDAY...WITH LAKE BREEZES IN THE
AFTERNOONS. THE GRADIENT TIGHTENS UP A BIT TUESDAY NIGHT THROUGH
WEDNESDAY WITH A WSW WIND NEARING ADVISORY LEVELS OVER LAKE
MICHIGAN. THIS WILL BE AHEAD OF A COLD FRONT THAT WILL SAG INTO
THE GREAT LAKES AND BRING A CHANCE FOR SHOWERS AND THUNDERSTORMS
LATER THIS WEEK.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...HALBLAUB
SYNOPSIS...JL
SHORT TERM...SD
LONG TERM...JL
AVIATION...SD
MARINE...SD
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1108 AM EDT MON AUG 20 2012
.SYNOPSIS...
ISSUED AT 339 AM EDT MON AUG 20 2012
ONE FINAL WAVE OF LOW PRESSURE IN THE SERIES WILL MOVE THROUGH THE
AREA TODAY AND THIS EVENING. THIS IS EXPECTED TO PRODUCE SOME
SHOWERS SOUTH OF I-96...WITH SOME SPRINKLES POSSIBLE ELSEWHERE. HIGH
PRESSURE IS THEN EXPECTED TO BUILD IN ACROSS THE AREA. THIS WILL
PROVIDE THE AREA WITH DRY CONDITIONS AND WARMING TEMPERATURES
THROUGH THE WEEK.
&&
.UPDATE...
ISSUED AT 1108 AM EDT MON AUG 20 2012
DID NOT MAKE SIGNIFICANT CHANGES TO THE GOING FORECAST BUT DID ADD
THE MENTION OF THUNDER ALONG THE I-94 CORRIDOR. SPC DAY ONE
OUTLOOK HAS GENERAL THUNDER IN THIS AREA AND CANNOT ARGUE.
MODIFYING THE MORNING SOUNDING FROM DTX TO A TEMP/DEW POINT OF
74/52 YIELDS CAPE VALUES IN THE 600-1000 J/KG RANGE AND LI/S AS
LOW AS -2 TO -3C. SHORTWAVE SEEN IN THE WATER VAPOR IMAGERY
DROPPING TOWARD LAKE SUPERIOR REACHES CENTRAL LAKE MICHIGAN JUST
AFTER MAX HEATING AND IT MAY BE ENOUGH TO ADD SOME SYNOPTIC SCALE
LIFT TO THINGS AS WELL. MESOSCALE MODELS...THE HRRR AND THE 4KM
WRF RUNS FROM SPC AND NSSL ALL INDICATE SOME ISOLATED TO SCATTERED
ACTIVITY DEVELOPING NEAR THE OLD FRONT TOWARD THE MICHIGAN/INDIANA
BORDER REGION AND ALONG THE LAKE BREEZE FRONT. BOTTOM LINE...HAVE
ISOLATED (20 PCT) ACROSS THE NORTHERN 3/4 OF THE AREA AND
SCATTERED (25 PCT) POPS TOWARDS I94. HIGHS SHOULD TOP OUT IN THE
MID TO UPPER 70S IN MOST AREAS.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 339 AM EDT MON AUG 20 2012
THE FIRST PERIOD OF THE FCST IS REALLY THE ONLY PERIOD IN WHICH ANY
WEATHER IS EXPECTED...AND THE IMPACT OF THE FIRST PERIOD WEATHER
SHOULD BE RATHER LIMITED WITH SHOWER POTENTIAL THE MAIN FOCUS.
WE ARE SEEING FOG DEVELOPING UP NORTH EARLY THIS MORNING AS EXPECTED
WHERE THERE WAS MORE WIDESPREAD RAINFALL YESTERDAY. THE MORE DENSE
FOG IS STILL RATHER LIMITED WITH ONLY KMOP AND KAMN REPORTING 1/2 TO
1/4SM THUS FAR IN THE CWFA. FOG IR SATELLITE IMAGERY INDICATES THAT
IT IS NOT WIDESPREAD ACROSS ANY OF OUR COUNTIES UP NORTH YET. WE
WILL CONTINUE TO MONITOR THE FOG THIS MORNING FOR ANY POSSIBLE
HEADLINES.
ONCE THE FOG IS GONE BY MID MORNING...THE FOCUS WILL TURN TO PCPN
CHCS. THERE IS ONE MORE UPPER WAVE THAT IS POISED TO MOVE THROUGH
THE REGION LATER TODAY AND TONIGHT. THIS WAVE IS CURRENTLY
APPROACHING LAKE SUPERIOR AND HEADING SOUTH. THIS WAVE IS EXPECTED
TO AMPLIFY A BIT AS IT MOVES IN. THE ISSUE IS THERE IS NOT A LOT OF
MOISTURE LEFT IN THE AREA TO WORK WITH AS THE FRONT THAT MOVED
THROUGH YESTERDAY TOOK THE BETTER MOISTURE WITH IT.
LOW LEVEL MOISTURE IS LACKING ACROSS MOST OF THE CWFA ASIDE FROM THE
FOG THIS MORNING...WITH THE BEST MOISTURE BEING FOUND ACROSS THE FAR
SRN PORTION OF THE CWFA. WE AGREE WITH THE MODELS THAT THE BEST CHCS
WILL BE SOUTH OF I-96. WE CAN NOT RULE OUT ANYTHING ELSEWHERE...BUT
IT WOULD LIKELY BE RATHER LIGHT WITH LIMITED LOW LEVEL MOISTURE. WE
HAVE GONE WITH SPRINKLES ELSEWHERE EXPECTING THEY WILL BE FALLING
FROM HIGHER CLOUD BASES.
WE CAN NOT RULE OUT THUNDER ALONG THE I-94 CORRIDOR AS MODELS SHOW
LI/S DROPPING TO AROUND 0 OR BARELY BELOW. FCST SOUNDINGS INDICATE
THAT WE WILL REALLY NOT SEE ANY CAPE ABOVE THE -20C ISOTHERM. THE
THREAT SEEMS TOO LOW AT THIS TIME TO ADD THUNDER IN.
ONCE THE DIURNAL INSTABILITY WANES THIS EVENING...WE EXPECT
CONDITIONS WILL BECOME DRY OVERNIGHT. THE TROUGH WILL STILL BE
PUSHING THROUGH. THE TROUGH AXIS WILL BE JUST ABOUT READY TO EXIT
THE CWFA AT 12Z TUE. AFTER THAT...WE WILL SEE UPPER RIDGING BUILD IN
ACROSS THE AREA. THIS WILL LAST THROUGH THE DAY ON WED AND LIKELY
BEYOND. TEMPS WILL MODERATE INTO THE 80S AS H850 TEMPS WARM TO THE
MID TEENS C.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 339 AM EDT MON AUG 20 2012
THE MAIN STORYLINE FOR THE LONG TERM PERIOD IS THAT WARMER THAN
NORMAL TEMPERATURES WILL RETURN AND STICK AROUND FOR AWHILE. THIS IS
IN RESPONSE TO RISING HEIGHTS AND LOW LEVEL SOUTHWEST FLOW.
WHILE NOT ZERO... THE CHANCE OF SHOWERS AND TSTMS LOOKS PRETTY LOW
THROUGH THE PERIOD. SFC RIDGING STILL DOMINATES ON THURSDAY... AND
THE SFC WARM FRONT IS EXPECTED TO BE SITUATED WELL TO OUR NORTH OVER
THE WEEKEND.
ONE FEATURE TO KEEP AN EYE ON IN FUTURE MODEL RUNS WILL BE A
NEGATIVELY TILTED H5 SHORTWAVE WHICH IS CURRENTLY PROGGED TO PASS
THROUGH THE REGION FRIDAY NIGHT AND SATURDAY. RIGHT NOW IT APPEARS
THAT THE BEST FORCING WITH THIS FEATURE WILL STAY TO OUR NORTHWEST
AND THAT THE WAVE WILL BE DEAMPLIFYING AS IT MOVES EAST.
ANOTHER SHORTWAVE IS PROGGED TO APPROACH FROM THE SOUTHWEST ON
SUNDAY AND WARRANTS KEEPING LOW CHANCE POPS IN THE FCST ATTM.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 747 AM EDT MON AUG 20 2012
AREAS OF SHALLOW GROUND FOG WILL DISSIPATE BY 13Z. OTHERWISE VFR
CONDITIONS WILL PREVAIL TODAY INTO TONIGHT. THE MAIN SHOWER/TSTM
RISK WILL BE SOUTH OF MICHIGAN... BUT CAN/T RULE OUT SOME ISOLATED
CELLS NEAR THE I-94 CORRIDOR. PATCHY SHALLOW GROUND FOG COULD
REDEVELOP LATE TONIGHT... BUT THE THREAT/COVERAGE IS TOO LOW TO
HAVE VSBY RESTRICTIONS IN THE TAFS ATTM.
&&
.MARINE...
ISSUED AT 339 AM EDT MON AUG 20 2012
THE ONLY CONCERN FOR MARINE INTERESTS WITH THIS FCST PACKAGE IS THE
CHC OF WATERSPOUTS AGAIN TODAY. A LAND BREEZE IS DEVELOPING THIS
MORNING...WHICH COULD CAUSE A BAND OF CLOUDS/SHOWERS THAT WOULD HAVE
THE POTENTIAL TO PRODUCE WATERSPOUTS. THE INSTABILITY AND POTENTIAL
CLOUD DEPTH OVER THE LAKE WOULD BE SUFFICIENT. WE ARE NOT SURE IF
THEY WILL COME TO FRUITION DUE TO THE UNCERTAINTY OF THE SHOWERS.
&&
.HYDROLOGY...
ISSUED AT 339 AM EDT MON AUG 20 2012
NO HYDROLOGY ISSUES ARE EXPECTED IN THE NEXT FEW DAYS AS A PERIOD OF
DRY WEATHER IS FORECAST FOR THE AREA. CHANCES OF RAIN WILL GRADUALLY
INCREASE LATE IN THE SEVEN DAY PERIOD...HOWEVER NOTHING LOOKS
NOTEWORTHY WITH REGARDS TO FLOODING AT THIS TIME.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...DUKE
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...NJJ
MARINE...NJJ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
739 AM EDT MON AUG 20 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 435 AM EDT MON AUG 20 2012
WATER VAPOR IMAGERY AND RUC ANALYSIS CONTINUE TO SHOW A DEEP TROF
DOMINATING THE ERN CONUS WITH THE TROF ANCHORED BY A MID/UPPER LEVEL
CYCLONE CENTERED IN THE VCNTY OF JAMES BAY. THE UPPER LAKES REMAIN
FIRMLY UNDER THE INFLUENCE OF THE TROF. ONE SHORTWAVE IS CURRENTLY
DROPPING THRU MN/NW WI WHILE ANOTHER IS UPSTREAM IN NORTHERN
ONTARIO. NOT MUCH IS HAPPENING WITH FIRST WAVE. AHEAD OF THE LATTER
WAVE...CANADIAN RADAR IMAGERY SHOWS SOME RETURNS IN THE VCNTY OF
LAKE NIPIGON THRU FAR ERN LAKE SUPERIOR. CLOUDS ARE NOW BEGINNING TO
DEVELOP S INTO UPPER MI. UP TO THIS POINT...MOSTLY CLEAR SKIES AND
LIGHT/CALM WIND HAS ALLOWED TEMPS TO FALL INTO THE MID/UPPER 30S IN
THE TRADITIONAL INTERIOR COLD SPOTS EARLY THIS MORNING.
WITH UPPER MI STILL UNDER THE INFLUENCE OF THE MID/UPPER TROF TODAY
AND TONIGHT...MAIN FCST ISSUE IS WHETHER ANY PCPN WILL OCCUR. AS
SHORTWAVE OVER NRN ONTARIO STREAKS S INTO THE AREA TODAY...IT
APPEARS THERE WILL BE ISOLD/SCT -SHRA...ESPECIALLY SINCE THERE ARE
ALREADY SOME -SHRA/SPRINKLES AHEAD OF FEATURE TO THE N OF LAKE
SUPERIOR. SINCE SHORTWAVE DROPS ACROSS WRN UPR MI AND INTO WI IN
THE AFTN...FCST AREA WILL BE ON THE FAVORABLE CYCLONIC SIDE OF
WAVE/UPPER JET STREAK. ARRIVAL DURING PEAK HEATING ARGUES FOR AT
LEAST ISOLD -SHRA MENTION OVER THE CNTRL/ERN FCST AREA. THE
SCNTRL/SE AREAS SHOULD HAVE BEST POTENTIAL FOR -SHRA AS LAKE BREEZE
COMPONENT TO THE WIND WILL INCREASE LOW-LEVEL CONVERGENCE IN THAT
AREA. WITH 850MB TEMPS IN THE 7 TO 9C RANGE...EXPECT MAX TEMPS
GENERALLY WITHIN A FEW DEGREES OF 70F.
ANY -SHRA OVER THE SCNTRL/SE FCST AREA WILL END QUICKLY THIS EVENING
AS SHORTWAVE EXITS THE AREA. WAA WILL THEN BEGIN TO GET UNDERWAY
TONIGHT AS ERN TROF RELAXES. MAIN PUSH OF WAA IS WELL TO THE N...SO
DON`T ANTICIPATE ANY PCPN CONCERNS. MAY SEE SOME MID CLOUDS. ANOTHER
NIGHT OF LIGHT/CALM WINDS WILL RESULT IN A COOL NIGHT. WITH
PRECIPITABLE WATER A LITTLE HIGHER THAN RECENT NIGHTS...MINS SHOULD
BE A BIT HIGHER. TEMPS SHOULD RANGE FROM THE 50S ALONG LAKE SUPERIOR
TO THE 40S INLAND. PROBABLY WON`T SEE ANY 30S AS HAS OCCURRED IN
RECENT NIGHTS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 435 AM EDT MON AUG 20 2012
OKAY AGREEMENT FROM THE MODELS WITH OVERALL LARGE SCALE PATTERN
THROUGH NEXT WEEKEND. STARTING THE LONG RANGE...TWO PRIMARY TROUGHS
ARE IN PLACE...ONE OVER MUCH OF EASTERN CANADA AND THE EASTERN CONUS
WITH OTHER DIGGING INTO PACIFIC NORTHWEST. RIDGE RESIDES IN BETWEEN
THE TWO WITH AXIS FROM SOUTHWEST CONUS NORTH TOWARD THE CANADIAN
ROCKIES. EASTERN CANADA TROUGH GRADUALLY LOSES AMPLITUDE OVER GREAT
LAKES...BUT THIS TAKES A WHILE...PROBABLY NOT UNTIL WED OR THU. ALL
THE WHILE...TROUGH OVER PACIFIC NORTHWEST SLOWLY MOVES INTO THE
UPPER RIDGE WITH SOME SUCCESS. ARRIVAL OF THE UPPER TROUGH OVER
UPPER MISSISSIPPI RIVER VALLEY IS SLATED FOR SOMETIME THU OR FRI.
GFS HAS HAD GOOD RUN-TO-RUN CONTINUITY WITH THIS FEATURE. LAST
COUPLE RUNS OF GEM-NHEM AND ECMWF ARE SHOWING THIS IDEA AS WELL
WHICH ADDS INCREASED CONFIDENCE TO THE SCENARIO.
ONCE THIS TROUGH MOVES THROUGH...EVEN A SHARPER TROUGH IS FORECAST
TO SLIDE THROUGH ACROSS SOUTH CENTRAL CANADA NEXT WEEKEND. THIS
LARGER SCALE TROUGH IS EVENTUALLY FORECAST TO DEVELOP AGAIN FROM
EASTERN CANADA INTO THE GREAT LAKES BY EARLY NEXT WEEK. AT THE
SURFACE...MAIN BOUNDARY LOOKS TO DROP INTO UPPER GREAT LAKES
WEDNESDAY. DESPITE THE FRONTAL BOUNDARY...STRONGER H85 TEMPERATURE
AND MOISTURE ADVECTION AFFECTS LAKE SUPERIOR TUESDAY NIGHT THEN
HEADS MORE EASTERLY ON WEDNESDAY. MODELS HINT THAT THERE MAY BE
ENOUGH H85-H7 MOISTURE POOLING ALONG THE FRONT TO COMBINE WITH
DAYTIME HEATING/SURFACE BASED CAPES AOA 500J/KG TO FORM SOME
SHRA/TSRA BY AFTERNOON. GFS IS BY FAR THE MOST BULLISH IN THIS IDEA.
OTHER MODELS PRETTY MUCH SHOVE NOTABLE MOISTURE TOO FAR EAST TO
DEVELOP MUCH OVER UPR MICHIGAN. PUNTED AND KEPT GOING SLIGHT
CHANCE POPS IN THE FORECAST ALONG THE FRONT...JUST DID NOT HAVE
REAL CONFIDENCE IN MAKING SIGNIFICANT CHANGES ON WEDNESDAY.
WITH LACK OF STEERING FLOW ALOFT...THIS FRONT MAY STALL OUT IN THE
VICINITY OF UPPER MICHIGAN THROUGH THU AND FRI.
BEST CHANCE OF RAIN IN THE LONG TERM PERIOD WILL BE ON FRIDAY
INTO SATURDAY AS PLAINS UPPER TROUGH AND INCREASING H85 MOISTURE
ADVECTION INTERACTS WITH THE SURFACE FRONT ALREADY IN THE AREA. THIS
BY NO MEANS REPRESENTS THE ONLY CHANCE OF RAIN THOUGH. ADDITIONAL
RAIN CHANCES /LOWER RANGE AT THIS POINT/ ARE IN THE FORECAST
WEDNESDAY AND THURSDAY AS ANY LOW-MID LEVEL RIPPLE ALONG THE SURFACE
BOUNDARY COULD KICK OFF ISOLD SHRA/TSRA SINCE RIBBON OF H85-H7
MOISTURE LINGERS OVER THE AREA. ALSO COULD SEE A PERIOD OF SHRA/TSRA
LATE IN THE WEEKEND INTO VERY EARLY NEXT WEEK AS THE STRONGER UPPER
LOW OVER SOUTH CENTRAL CANADA DRAWS CLOSER TO THE AREA ALONG WITH
ANOTHER ROUND OF LOW-LEVEL TEMP/MOISTURE ADVECTION PRECEEDING IT.
FORECAST TEMPERATURES THROUGH THE LONG TERM WILL SHOW WARMING TREND.
CLOUDS/PRECIP COULD IMPACT THE WARMING ANY DAY FROM THURSDAY THROUGH
END OF LONGER TERM...BUT GIVEN H85 TEMPS CLIMBING AOA +15C THINK
TRENDING TEMPS WARMER IS A GOOD STRATEGY. EXPECT HIGHS UPPER 70S TO
LOWER 80S WEDNESDAY THROUGH FRIDAY...WITH POSSIBLY EVEN WARMER TEMPS
WEDNESDAY AND/OR THURSDAY IF CLOUDS/PRECIP TURN OUT TO BE NOT MUCH
OF A FACTOR. MORE WARMTH EXPECTED FOR THE UPCOMING WEEKEND OUT AHEAD
OF THE DEEPER TROUGH OVER CENTRAL CANADA. GENERAL SW WIND AND H85
TEMPS AROUND +17C SUGGEST WIDESPREAD 80S COULD OCCUR...AGAIN IF
CLOUDS AND PRECIP ARE NOT AN ISSUE. TOUGH TO SAY HOW WEEKEND WILL
TURN OUT THOUGH. GFS IS QUITE AGREESSIVE IN CLEARING LEADING SYSTEM
OUT FRIDAY NIGHT WHILE ECMWF IS SOMEWHAT SLOWER. GFS STAYS QUICK IN
BRINGING NEXT BATCH OF SHRA/TSRA INTO UPR LAKES BY SUNDAY WHILE
ECMWF IS AGAIN SLOWER. CONSENSUS HAS TO WORK FOR NOW FOR POPS GIVEN
THESE DIFFERENCES...BUT DID GO AHEAD AND INCREASE TEMPS OVER THE
CONSENSUS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 737 AM EDT MON AUG 20 2012
PER WATER VAPOR SATELLITE IMAGERY...AN INCREASINGLY WELL-DEFINED
SHORTWAVE DROPPING S THRU NRN ONTARIO TOWARD WRN LAKE SUPERIOR IS
THE MAIN FEATURE OF INTEREST. ARRIVAL OF WAVE DURING PEAK HEATING
SUGGESTS SOME -SHRA WILL DEVELOP TODAY. SINCE TRACK OF DISTURBANCE
THRU WRN UPPER MI PLACES KSAW UNDER THE MORE FAVORABLE CYCLONIC SIDE
OF SHORTWAVE/UPPER JET STREAK...OPTED TO INCLUDE VCSH MENTION AT KSAW
THIS AFTN. EVEN IF A -SHRA PASSES OVER KSAW...VFR CONDITIONS SHOULD
STILL PREVAIL SINCE LOW-LEVELS ARE RELATIVELY DRY TODAY. RELATIVELY
DRY LOW-LEVELS WILL ALSO KEEP CONDITIONS VFR AT KIWD/KCMX THRU THE
FCST PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 435 AM EDT MON AUG 20 2012
WEAK PRESSURE GRADIENT DOMINATES UPPER GREAT LAKES MOST OF THIS WEEK
INTO NEXT WEEKEND SO EXPECT WINDS AOB 20 KTS. ONLY EXCEPTION COULD
BE LATER TUESDAY INTO TUESDAY NIGHT AS SOUTHWEST WINDS MAY GUST TO
25 KTS OVER WESTERN AND NORTH CENTRAL LK SUPERIOR OUT AHEAD OF FRONT
DROPPING IN FROM NORTHERN ONTARIO. CHANCES FOR ANY SHRA/TSRA WILL BE
SPOTTY UNTIL STRONGER DISTURBANCE BRINGS GOOD CHANCE OF SHRA/TSRA TO
THE REGION FRIDAY INTO NEXT WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...JLA
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1036 AM EDT MON AUG 20 2012
.SYNOPSIS...
A SLOW MOVING FRONT...IN COMBINATION WITH AN UPPER LEVEL
DISTURBANCE...WILL BRING THE CHANCE FOR SHOWERS AND ISOLATED
THUNDERSTORMS TO THE REGION TODAY. A STALLED FRONT TO OUR EAST AND
AN UPPER LEVEL DISTURBANCE COULD TRIGGER A FEW ISOLATED SHOWERS OR
EVEN THUNDERSTORMS TUESDAY AFTERNOON...ESPECIALLY IN NORTHEAST
PENNSYLVANIA. HIGH PRESSURE WILL BUILD INTO THE REGION FOR
WEDNESDAY AND WEDNESDAY NIGHT WITH FAIR WEATHER EXPECTED.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED AT 1030 AM... CURRENTLY TRACKING WAVES WHICH WILL BE
GENERATING AREAS OF SHOWERS MOVING NORTHEAST ACROSS THE AREA IN
SOUTHWEST FLOW ALOFT TODAY. FIRST BATCH OF SHOWERS IS NOW MOVING
FROM BRADFORD COUNTY TOWARD BROOME... SUSQUEHANNA AND TIOGA
COUNTIES WITH LIGHTER SHOWERS ALSO DEVELOPING TO THE NORTHWEST AND
SOUTHEAST OF THE MAIN AREA OF SHOWERS. MODELS CONTINUE TO INDICATE
FAVORABLE CONDITIONS FOR WEAK LIFT ACROSS MOST OF THE AREA TODAY
WITH A WEAK BAND OF MID-LEVEL FRONTOGENESIS ORIENTED FROM
SOUTHWEST TO NORTHEAST ACROSS UPSTATE NY. BASED ON THIS EXPECT
THIS FIRST BATCH OF SHOWERS TO HOLD TOGETHER AND MOVE NORTHEAST
TOWARD THE WESTERN CATSKILLS EARLY THIS AFTERNOON... WHILE OTHER
AREAS OF SHOWERS CONTINUE TO DEVELOP ELSEWHERE ACROSS THE CWA.
CURRENT POPS ARE REFLECTING THIS SCENARIO WITH HIGH LIKELY TO
CATEGORICAL SPREADING FROM SUSQUEHANNA COUNTY PA TOWARD THE
CATSKILLS... WHILE HIGH CHC POPS DEVELOP ELSEWHERE ACROSS THE AREA
THROUGH MID- AFTERNOON. PREVIOUS DISCUSSION BELOW.
UPDATE AT 7 AM...QUICK UPDATE TO ADJUST POPS AND TIMING...WINDS
AND TEMPS JUST TWEAKS. NO MAJOR CHANGES TO THE NEAR TERM.
UPDATED AS OF 4 AM...MINOR CHANGES TO POPS AS CONVECTIVE ACTVTY HAS
RAPIDLY DIMINISHED IN WRN NY UPON REACHING C NY. I DON/T EXPECT
MUCH MORE ACTVY UNTIL LATER OVERNIGHT WHEN SOME ISLD ACVTY CUD
REACH NE PA. OTHERWISE NO MAJOR CHANGES FROM EARLIER UPDATE.
PREVIOUS DSCN BELOW...
RADAR SHOWS SCATTERED PATCHES OF SHOWERS AND ISOLATED
THUNDERSTORMS MOVING NORTHEAST FROM PA INTO SC NY EARLY THIS
MORNING. THIS ACVTY WAS BEING SUPPORTED BY A SMALL UPPER LEVEL
RIPPLE SEEN WELL IN THE WATER VAPOR SATELLITE IMAGERY. THIS UPPER
LEVEL FEATURE WAS MOVING NORTHEAST TWD PA AND NY FROM WEST
VIRGINIA AND SUPPORTED A WEAK SFC LO OVER SERN OH. THIS UPPER
LEVEL WAVE AND ASSCTD SFC FEATURE WILL CONTINUE TO MOVE NORTHEAST
EARLY THIS MORNING BEFORE GETTING CAUGHT UP IN AN UPPER LEVEL
CONFLUENCE ZONE THAT WAS HANGING TOUGH BETWEEN AND STATIONARY
UPPER LEVEL LOW OVER JAMES BAY CANADA AND THE EVER PRESENT
SUBTROPICAL UPPER LEVEL RIDGE COMMON THIS TIME OF YEAR WELL OFF
THE EAST COAST. THUS THE WAVE AND ASSCTD SFC FEATURE WILL SHEAR
OUT BTWN 6Z AND 12Z AND THE PRECIPITATION THAT IT WAS SUPPORTING
WILL WEAKEN AS IT MOVES FARTHER NORTH AND EAST. TRENDS ON RADAR
INDICATE THIS. WATER VAPOR IMAGERY SHOWS IT WELL.
THE ONLY MODEL THAT SEEMS TO HAVE SOMEWHAT OF A HANDLE ON THE QPF
WITH THIS WEAK SYSTEM IS THE GFS...KEEPING SOME LIGHT QPF ACROSS
MUCH OF CENTRAL NY UNTIL ARND 6Z BEFORE WEAKENING IT. THE NAM HAS
NO PRECIP...THE LATEST CONVECTION ALLOWING HI RES WRF ARW AND WRF
NMM DO NOT HAVE ANY PRECIP TONIGHT FOR OUR AREA. THE RAP IS DOING A
BETTER JOB BUT HAS TOO MUCH COVERAGE SIMILAR TO THE GFS BUT MORE
IN NRN PA WHEN MOST OF THE ACVTY IS IN THE WRN PART OF NY. MODEL
SOUNDINGS ALL SHOW SOME WEAK COOLING ALOFT WITH THIS WAVE INITIALLY
BTWN 600 AND 500 MB WHICH ON SOME MODEL SOUNDINGS IS STILL CAPPED
BUT ON THE GFS AND SREF SOUNDINGS ARE NOT. THE RUC ALSO ALLOWS FOR
SOME SMALL CAPE. SO IT IS A VERY MARGINAL SITUATION FOR PRECIP.
ALL MODELS TREND THIS ACVTY DOWN OVERNIGHT SO WILL GO ALONG WITH
THAT TREND USING CURRENT RADAR TRENDS WHICH IS AN IMPROVEMENT OVER
THE MODELS. THERE IS SOME ELEVATED CAPE SO MAYBE A RUMBLE OF
THUNDER...BUT NOTHING SIGNIFICANT OVERNIGHT.
FOR TODAY...ANOTHER SHORT WAVE MO/IL WILL ROUND THE BASE OF THE
UPPER LEVEL TROF OVER THE GREAT LAKES AND OH VLLY AND LIFT
NORTHEASTWARD TODAY. THIS FEATURE WILL SUPPORT LIFTG AND COOLING
AT MID-LEVELS COINCIDENT WITH THE DAYTIME HEATING SUPPORTG SCT
SHWRS AND TSRA FORMING DURG THE DAY INTO THE AFTERNOON. CAPES ON
ALL MODELS ARE MARGINAL RUNNING ONLY IN THE HUNDREDS...GENERALLY
LESS THAN 500 J/KG. THE SHEAR IS WEAK BELOW 6 KM WHICH IS WHERE
MOST OF THE CAPE IS...SO THE EFFECTIVE SHEAR IS WEAK. THERE IS
STRONGER SHEAR ALOFT FROM 6KM ON UP BUT DO NOT BELIEVE WITH SUCH
LOW CAPE VALUES THAT WE WILL SEE ANY SVR WEATHER. ANY STORM THAT
CAN REACH THESE HIGHER ALTITUDES LIKELY WILL GET SHEARED OUT
ANYWAY. SO JUST HAVE CHC POPS FOR LATER IN THE DAY INTO THE
AFTERNOON.
SHOWERS AND THUNDERSTORMS WILL WANE QUICKLY THIS EVENING AS THIS
NEXT SHORTWAVE SHEARS OUT IN THIS EVER PRESENT CONFLUENT ZONE
OVERHEAD TONIGHT. THIS OCCURS COINCIDENT WITH THE LOSS OF THE
DAY/S HEATING. FURTHERMORE WITH STRGR UPPER CONFLUENCE...A SFC
RIDGE WILL FORM OVER THE REGION...LEADING TO SOME POTENTIAL
CLEARING. WILL MONITOR FOR POTENTIAL VALLEY FOG LATE TONIGHT WITH
SHORT TERM UPDATE COMING SOON.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
TUESDAY WILL BEGIN WITH SCT-BKN MID-HI CLDS ARND AS A STRUNG OUT
FRONTL SYSTEM IS STALLED OFFSHORE WITH A DEPARTING SFC WAVE. THE
CMC AND NAM ARE STRONGEST WITH THE SFC WAVE DEVELOPMENT WITH THE
EURO AND GFS MUCH MORE WEAKER FLATTER WITH THE PRESSURE FIELD
OFFSHORE. THIS MAKES A DIFFERENCE FOR OUR AREA IN THAT THE NAM AND
CMC HAVE A STRONGER LL HIGH PRESSURE SYSTEM OVER OUR AREA TUESDAY
WHICH TENDS TO SUPRESS CONVECTIVE DEVELOPMENT. THE NAM MODEL
SOUNDINGS FOR TUESDAY DON/T PRODUCE ANY SIGNIFICANT CAPE AND APPEAR
CAPPED TO SOME EXTENT BY A MID-LVL INVERSION. THE EURO AND GFS
HAVE A WEAKER SFC PRESSURE RDG OVER OUR AREA WITH MORE LOW-LEVEL
MOISTURE HANGING ARND. THE GFS SOUNDINGS DO GENERATE CAPE WITH THE
AFTERNOON HEATING SUGGESTIVE OF ISLD TO SCT SHRA AND EVEN SOME
TSRA. LI/S ARE SLIGHTLY NEGATIVE ON THE GFS WITH CAPES IN THE
HUNDREDS AGAIN....MAINLY FROM THE SRN TIER INTO NRN PA. SO NOTHING
MAJOR. WIND SHEARS ARE WEAK AND CAPE IS NOT IMPRESSIVE SO WILL
HAVE ISLD TO SCT SHRA AND TSRA WITH HIGHEST POPS IN NE PA AND
LOWER POPS AS YOU TRAVEL N INTO NC NY WHERE CAPE IS MINIMAL.
FOR TUESDAY NIGHT...ALL CONVECTIVE ACVTY WINDS DOWN WITH LOSS OF
DAY/S HEATING. SFC HIGH PRESSURE DOMINATES ON ALL MODELS AND THERE
IS LARGE SCALE SUBSC. SO WILL WIND DOWN ANY RESIDUAL POPS FROM THE
EARLY EVENING.
FOR WEDNESDAY AND WEDNESDAY NIGHT...HIGH PRESSURE TAKES CONTROL WITH
LARGE SCALE SUBSC AND MORE STBL AIR IN PLACE. SO WED CUD BE THE
NICEST DAY OF THIS FORECAST PD.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
4 AM MON UPDATE... OVERALL...A QUIET PD STILL LOOKS TO BE IN THE
OFFING FOR NY/PA...AS THE LATEST EC/GFS AND ASSOCD ENSEMBLE MEANS
CONTINUE TO INDICATE THAT A FLAT UPR-LVL TROUGH AXIS ACRS THE ERN
CONUS WILL FURTHER DE-AMPLIFY WITH TIME. IN FACT...THE LATEST
RUNS NOW ACTUALLY INDICATE A NARROW RIDGE AXIS DEVELOPING BY LATER
NEXT WEEKEND.
AT THE SFC...THE MAIN BAROCLINIC ZNS/FRNTS MOSTLY STAY SITUATED
WELL TO OUR S THROUGH THE SRN MID-ATL...AND ALSO UPSTREAM THROUGH
SRN CANADA AND THE NRN LKS RGN. TWDS NEXT SUN/MON...THE LATTER
SYSTEM MAY TRY TO EDGE CLOSE ENOUGH TO BRING ISOLD DIURNALLY DRIVEN
CONVECTION. FOR NOW...THE SCHC POPS WE HAVE IN THERE WILL SUFFICE.
TEMPS SHOULD UNDERGO A GRADUAL WARMING TREND UNDER RISING HGTS
ALOFT...WITH DAILY HIGHS MAINLY IN THE 80S BY NEXT WEEKEND.
PREV DISC... SUBTLE FEATURES WILL INFLUENCE THE WX IN THE LONG
TERM AS THE SFC RDGG BRKS DOWN EARLY IN THE PD. OPERATIONAL MODELS
SHOW A WEAK FNTL BNDRY TRYING TO DROP SOUTH FROM CANADA FRI INTO
SAT BEFORE EVENTUALLY WASHING OUT OVER THE AREA. WITH HTG...THIS
MAY BE ENUF LL CONV TO DVLP ISLTD AFTN CONV FRI AND SAT.
TEMPS WILL SHOW A GRADUAL RECOVERY THRU THE PD...RCHG ABV NRML BY
FRI AND SAT. STILL DFRNCS BETWEEN HPC GUID AND GFS GENERATED
MEX...SO BLENDED GUID WITH PRVS FCST TO CONT A SLOW UPWARD TREND.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
12Z MON UPDATE... MAINLY VFR SHOULD PREVAIL TIL MIDDAY (15-17Z).
THIS AFTN...CONDS SHOULD LWR TO MVFR...AS SHRA BECOME MORE
WIDESPREAD...JUST AHEAD OF A WEAK COLD FRNT.
THIS EVE...CONDS SHOULD GRADUALLY IMPROVE TO VFR FROM NW TO
SE...AS THE FRNT EASES ACRS THE RGN.
S TO SW SFC WINDS TDY...WILL BECOME LGT AND VRBL TNT.
OUTLOOK...
TUE...MOSTLY VFR...WITH BRIEF RESTRICTIONS PSBL IN THE AFTN FROM
ISOLD SHRA/TSRA.
WED/THU/FRI...MAINLY VFR. MRNG VLY FOG PSBL WITH IFR AT KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...MSE
SHORT TERM...
LONG TERM...DGM/MLJ
AVIATION...MLJ/RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
709 AM EDT MON AUG 20 2012
.SYNOPSIS...
A SLOW MOVING FRONT...IN COMBINATION WITH AN UPPER LEVEL
DISTURBANCE...WILL BRING THE CHANCE FOR SHOWERS AND ISOLATED
THUNDERSTORMS TO THE REGION TODAY. A STALLED FRONT TO OUR EAST AND
AN UPPER LEVEL DISTURBANCE COULD TRIGGER A FEW ISOLATED SHOWERS OR
EVEN THUNDERSTORMS TUESDAY AFTERNOON...ESPECIALLY IN NORTHEAST
PENNSYLVANIA. HIGH PRESSURE WILL BUILD INTO THE REGION FOR
WEDNESDAY AND WEDNESDAY NIGHT WITH FAIR WEATHER EXPECTED.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE AT 7 AM...QUICK UPDATE TO ADJUST POPS AND TIMING...WINDS
AND TEMPS JUST TWEAKS. NO MAJOR CHANGES TO THE NEAR TERM.
UPDATED AS OF 4 AM...MINOR CHANGES TO POPS AS CONVECTIVE ACTVTY HAS
RAPIDLY DIMINISHED IN WRN NY UPON REACHING C NY. I DON/T EXPECT
MUCH MORE ACTVY UNTIL LATER OVERNIGHT WHEN SOME ISLD ACVTY CUD
REACH NE PA. OTHERWISE NO MAJOR CHANGES FROM EARLIER UPDATE.
PREVIOUS DSCN BELOW...
RADAR SHOWS SCATTERED PATCHES OF SHOWERS AND ISOLATED
THUNDERSTORMS MOVING NORTHEAST FROM PA INTO SC NY EARLY THIS
MORNING. THIS ACVTY WAS BEING SUPPORTED BY A SMALL UPPER LEVEL
RIPPLE SEEN WELL IN THE WATER VAPOR SATELLITE IMAGERY. THIS UPPER
LEVEL FEATURE WAS MOVING NORTHEAST TWD PA AND NY FROM WEST
VIRGINIA AND SUPPORTED A WEAK SFC LO OVER SERN OH. THIS UPPER
LEVEL WAVE AND ASSCTD SFC FEATURE WILL CONTINUE TO MOVE NORTHEAST
EARLY THIS MORNING BEFORE GETTING CAUGHT UP IN AN UPPER LEVEL
CONFLUENCE ZONE THAT WAS HANGING TOUGH BETWEEN AND STATIONARY
UPPER LEVEL LOW OVER JAMES BAY CANADA AND THE EVER PRESENT
SUBTROPICAL UPPER LEVEL RIDGE COMMON THIS TIME OF YEAR WELL OFF
THE EAST COAST. THUS THE WAVE AND ASSCTD SFC FEATURE WILL SHEAR
OUT BTWN 6Z AND 12Z AND THE PRECIPITATION THAT IT WAS SUPPORTING
WILL WEAKEN AS IT MOVES FARTHER NORTH AND EAST. TRENDS ON RADAR
INDICATE THIS. WATER VAPOR IMAGERY SHOWS IT WELL.
THE ONLY MODEL THAT SEEMS TO HAVE SOMEWHAT OF A HANDLE ON THE QPF
WITH THIS WEAK SYSTEM IS THE GFS...KEEPING SOME LIGHT QPF ACROSS
MUCH OF CENTRAL NY UNTIL ARND 6Z BEFORE WEAKENING IT. THE NAM HAS
NO PRECIP...THE LATEST CONVECTION ALLOWING HI RES WRF ARW AND WRF
NMM DO NOT HAVE ANY PRECIP TONIGHT FOR OUR AREA. THE RAP IS DOING A
BETTER JOB BUT HAS TOO MUCH COVERAGE SIMILAR TO THE GFS BUT MORE
IN NRN PA WHEN MOST OF THE ACVTY IS IN THE WRN PART OF NY. MODEL
SOUNDINGS ALL SHOW SOME WEAK COOLING ALOFT WITH THIS WAVE INITIALLY
BTWN 600 AND 500 MB WHICH ON SOME MODEL SOUNDINGS IS STILL CAPPED
BUT ON THE GFS AND SREF SOUNDINGS ARE NOT. THE RUC ALSO ALLOWS FOR
SOME SMALL CAPE. SO IT IS A VERY MARGINAL SITUATION FOR PRECIP.
ALL MODELS TREND THIS ACVTY DOWN OVERNIGHT SO WILL GO ALONG WITH
THAT TREND USING CURRENT RADAR TRENDS WHICH IS AN IMPROVEMENT OVER
THE MODELS. THERE IS SOME ELEVATED CAPE SO MAYBE A RUMBLE OF
THUNDER...BUT NOTHING SIGNIFICANT OVERNIGHT.
FOR TODAY...ANOTHER SHORT WAVE MO/IL WILL ROUND THE BASE OF THE
UPPER LEVEL TROF OVER THE GREAT LAKES AND OH VLLY AND LIFT
NORTHEASTWARD TODAY. THIS FEATURE WILL SUPPORT LIFTG AND COOLING
AT MID-LEVELS COINCIDENT WITH THE DAYTIME HEATING SUPPORTG SCT
SHWRS AND TSRA FORMING DURG THE DAY INTO THE AFTERNOON. CAPES ON
ALL MODELS ARE MARGINAL RUNNING ONLY IN THE HUNDREDS...GENERALLY
LESS THAN 500 J/KG. THE SHEAR IS WEAK BELOW 6 KM WHICH IS WHERE
MOST OF THE CAPE IS...SO THE EFFECTIVE SHEAR IS WEAK. THERE IS
STRONGER SHEAR ALOFT FROM 6KM ON UP BUT DO NOT BELIEVE WITH SUCH
LOW CAPE VALUES THAT WE WILL SEE ANY SVR WEATHER. ANY STORM THAT
CAN REACH THESE HIGHER ALTITUDES LIKELY WILL GET SHEARED OUT
ANYWAY. SO JUST HAVE CHC POPS FOR LATER IN THE DAY INTO THE
AFTERNOON.
SHOWERS AND THUNDERSTORMS WILL WANE QUICKLY THIS EVENING AS THIS
NEXT SHORTWAVE SHEARS OUT IN THIS EVER PRESENT CONFLUENT ZONE
OVERHEAD TONIGHT. THIS OCCURS COINCIDENT WITH THE LOSS OF THE
DAY/S HEATING. FURTHERMORE WITH STRGR UPPER CONFLUENCE...A SFC
RIDGE WILL FORM OVER THE REGION...LEADING TO SOME POTENTIAL
CLEARING. WILL MONITOR FOR POTENTIAL VALLEY FOG LATE TONIGHT WITH
SHORT TERM UPDATE COMING SOON.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
TUESDAY WILL BEGIN WITH SCT-BKN MID-HI CLDS ARND AS A STRUNG OUT
FRONTL SYSTEM IS STALLED OFFSHORE WITH A DEPARTING SFC WAVE. THE
CMC AND NAM ARE STRONGEST WITH THE SFC WAVE DEVELOPMENT WITH THE
EURO AND GFS MUCH MORE WEAKER FLATTER WITH THE PRESSURE FIELD
OFFSHORE. THIS MAKES A DIFFERENCE FOR OUR AREA IN THAT THE NAM AND
CMC HAVE A STRONGER LL HIGH PRESSURE SYSTEM OVER OUR AREA TUESDAY
WHICH TENDS TO SUPRESS CONVECTIVE DEVELOPMENT. THE NAM MODEL
SOUNDINGS FOR TUESDAY DON/T PRODUCE ANY SIGNIFICANT CAPE AND APPEAR
CAPPED TO SOME EXTENT BY A MID-LVL INVERSION. THE EURO AND GFS
HAVE A WEAKER SFC PRESSURE RDG OVER OUR AREA WITH MORE LOW-LEVEL
MOISTURE HANGING ARND. THE GFS SOUNDINGS DO GENERATE CAPE WITH THE
AFTERNOON HEATING SUGGESTIVE OF ISLD TO SCT SHRA AND EVEN SOME
TSRA. LI/S ARE SLIGHTLY NEGATIVE ON THE GFS WITH CAPES IN THE
HUNDREDS AGAIN....MAINLY FROM THE SRN TIER INTO NRN PA. SO NOTHING
MAJOR. WIND SHEARS ARE WEAK AND CAPE IS NOT IMPRESSIVE SO WILL
HAVE ISLD TO SCT SHRA AND TSRA WITH HIGHEST POPS IN NE PA AND
LOWER POPS AS YOU TRAVEL N INTO NC NY WHERE CAPE IS MINIMAL.
FOR TUESDAY NIGHT...ALL CONVECTIVE ACVTY WINDS DOWN WITH LOSS OF
DAY/S HEATING. SFC HIGH PRESSURE DOMINATES ON ALL MODELS AND THERE
IS LARGE SCALE SUBSC. SO WILL WIND DOWN ANY RESIDUAL POPS FROM THE
EARLY EVENING.
FOR WEDNESDAY AND WEDNESDAY NIGHT...HIGH PRESSURE TAKES CONTROL WITH
LARGE SCALE SUBSC AND MORE STBL AIR IN PLACE. SO WED CUD BE THE
NICEST DAY OF THIS FORECAST PD.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
4 AM MON UPDATE... OVERALL...A QUIET PD STILL LOOKS TO BE IN THE
OFFING FOR NY/PA...AS THE LATEST EC/GFS AND ASSOCD ENSEMBLE MEANS
CONTINUE TO INDICATE THAT A FLAT UPR-LVL TROUGH AXIS ACRS THE ERN
CONUS WILL FURTHER DE-AMPLIFY WITH TIME. IN FACT...THE LATEST
RUNS NOW ACTUALLY INDICATE A NARROW RIDGE AXIS DEVELOPING BY LATER
NEXT WEEKEND.
AT THE SFC...THE MAIN BAROCLINIC ZNS/FRNTS MOSTLY STAY SITUATED
WELL TO OUR S THROUGH THE SRN MID-ATL...AND ALSO UPSTREAM THROUGH
SRN CANADA AND THE NRN LKS RGN. TWDS NEXT SUN/MON...THE LATTER
SYSTEM MAY TRY TO EDGE CLOSE ENOUGH TO BRING ISOLD DIURNALLY DRIVEN
CONVECTION. FOR NOW...THE SCHC POPS WE HAVE IN THERE WILL SUFFICE.
TEMPS SHOULD UNDERGO A GRADUAL WARMING TREND UNDER RISING HGTS
ALOFT...WITH DAILY HIGHS MAINLY IN THE 80S BY NEXT WEEKEND.
PREV DISC... SUBTLE FEATURES WILL INFLUENCE THE WX IN THE LONG
TERM AS THE SFC RDGG BRKS DOWN EARLY IN THE PD. OPERATIONAL MODELS
SHOW A WEAK FNTL BNDRY TRYING TO DROP SOUTH FROM CANADA FRI INTO
SAT BEFORE EVENTUALLY WASHING OUT OVER THE AREA. WITH HTG...THIS
MAY BE ENUF LL CONV TO DVLP ISLTD AFTN CONV FRI AND SAT.
TEMPS WILL SHOW A GRADUAL RECOVERY THRU THE PD...RCHG ABV NRML BY
FRI AND SAT. STILL DFRNCS BETWEEN HPC GUID AND GFS GENERATED
MEX...SO BLENDED GUID WITH PRVS FCST TO CONT A SLOW UPWARD TREND.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
12Z MON UPDATE... MAINLY VFR SHOULD PREVAIL TIL MIDDAY (15-17Z).
THIS AFTN...CONDS SHOULD LWR TO MVFR...AS SHRA BECOME MORE
WIDESPREAD...JUST AHEAD OF A WEAK COLD FRNT.
THIS EVE...CONDS SHOULD GRADUALLY IMPROVE TO VFR FROM NW TO
SE...AS THE FRNT EASES ACRS THE RGN.
S TO SW SFC WINDS TDY...WILL BECOME LGT AND VRBL TNT.
OUTLOOK...
TUE...MOSTLY VFR...WITH BRIEF RESTRICTIONS PSBL IN THE AFTN FROM
ISOLD SHRA/TSRA.
WED/THU/FRI...MAINLY VFR. MRNG VLY FOG PSBL WITH IFR AT KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...
LONG TERM...DGM/MLJ
AVIATION...MLJ/RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
649 AM EDT MON AUG 20 2012
.SYNOPSIS...
A SLOW MOVING FRONT...IN COMBINATION WITH AN UPPER LEVEL
DISTURBANCE...WILL BRING THE CHANCE FOR SHOWERS AND ISOLATED
THUNDERSTORMS TO THE REGION TODAY. A STALLED FRONT TO OUR EAST AND
AN UPPER LEVEL DISTURBANCE COULD TRIGGER A FEW ISOLATED SHOWERS OR
EVEN THUNDERSTORMS TUESDAY AFTERNOON...ESPECIALLY IN NORTHEAST
PENNSYLVANIA. HIGH PRESSURE WILL BUILD INTO THE REGION FOR
WEDNESDAY AND WEDNESDAY NIGHT WITH FAIR WEATHER EXPECTED.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED AS OF 4 AM...MINOR CHANGES TO POPS AS CONVECTIVE ACTVTY HAS
RAPIDLY DIMINISHED IN WRN NY UPON REACHING C NY. I DON/T EXPECT
MUCH MORE ACTVY UNTIL LATER OVERNIGHT WHEN SOME ISLD ACVTY CUD
REACH NE PA. OTHERWISE NO MAJOR CHANGES FROM EARLIER UPDATE.
PREVIOUS DSCN BELOW...
RADAR SHOWS SCATTERED PATCHES OF SHOWERS AND ISOLATED
THUNDERSTORMS MOVING NORTHEAST FROM PA INTO SC NY EARLY THIS
MORNING. THIS ACVTY WAS BEING SUPPORTED BY A SMALL UPPER LEVEL
RIPPLE SEEN WELL IN THE WATER VAPOR SATELLITE IMAGERY. THIS UPPER
LEVEL FEATURE WAS MOVING NORTHEAST TWD PA AND NY FROM WEST
VIRGINIA AND SUPPORTED A WEAK SFC LO OVER SERN OH. THIS UPPER
LEVEL WAVE AND ASSCTD SFC FEATURE WILL CONTINUE TO MOVE NORTHEAST
EARLY THIS MORNING BEFORE GETTING CAUGHT UP IN AN UPPER LEVEL
CONFLUENCE ZONE THAT WAS HANGING TOUGH BETWEEN AND STATIONARY
UPPER LEVEL LOW OVER JAMES BAY CANADA AND THE EVER PRESENT
SUBTROPICAL UPPER LEVEL RIDGE COMMON THIS TIME OF YEAR WELL OFF
THE EAST COAST. THUS THE WAVE AND ASSCTD SFC FEATURE WILL SHEAR
OUT BTWN 6Z AND 12Z AND THE PRECIPITATION THAT IT WAS SUPPORTING
WILL WEAKEN AS IT MOVES FARTHER NORTH AND EAST. TRENDS ON RADAR
INDICATE THIS. WATER VAPOR IMAGERY SHOWS IT WELL.
THE ONLY MODEL THAT SEEMS TO HAVE SOMEWHAT OF A HANDLE ON THE QPF
WITH THIS WEAK SYSTEM IS THE GFS...KEEPING SOME LIGHT QPF ACROSS
MUCH OF CENTRAL NY UNTIL ARND 6Z BEFORE WEAKENING IT. THE NAM HAS
NO PRECIP...THE LATEST CONVECTION ALLOWING HI RES WRF ARW AND WRF
NMM DO NOT HAVE ANY PRECIP TONIGHT FOR OUR AREA. THE RAP IS DOING A
BETTER JOB BUT HAS TOO MUCH COVERAGE SIMILAR TO THE GFS BUT MORE
IN NRN PA WHEN MOST OF THE ACVTY IS IN THE WRN PART OF NY. MODEL
SOUNDINGS ALL SHOW SOME WEAK COOLING ALOFT WITH THIS WAVE INITIALLY
BTWN 600 AND 500 MB WHICH ON SOME MODEL SOUNDINGS IS STILL CAPPED
BUT ON THE GFS AND SREF SOUNDINGS ARE NOT. THE RUC ALSO ALLOWS FOR
SOME SMALL CAPE. SO IT IS A VERY MARGINAL SITUATION FOR PRECIP.
ALL MODELS TREND THIS ACVTY DOWN OVERNIGHT SO WILL GO ALONG WITH
THAT TREND USING CURRENT RADAR TRENDS WHICH IS AN IMPROVEMENT OVER
THE MODELS. THERE IS SOME ELEVATED CAPE SO MAYBE A RUMBLE OF
THUNDER...BUT NOTHING SIGNIFICANT OVERNIGHT.
FOR TODAY...ANOTHER SHORT WAVE MO/IL WILL ROUND THE BASE OF THE
UPPER LEVEL TROF OVER THE GREAT LAKES AND OH VLLY AND LIFT
NORTHEASTWARD TODAY. THIS FEATURE WILL SUPPORT LIFTG AND COOLING
AT MID-LEVELS COINCIDENT WITH THE DAYTIME HEATING SUPPORTG SCT
SHWRS AND TSRA FORMING DURG THE DAY INTO THE AFTERNOON. CAPES ON
ALL MODELS ARE MARGINAL RUNNING ONLY IN THE HUNDREDS...GENERALLY
LESS THAN 500 J/KG. THE SHEAR IS WEAK BELOW 6 KM WHICH IS WHERE
MOST OF THE CAPE IS...SO THE EFFECTIVE SHEAR IS WEAK. THERE IS
STRONGER SHEAR ALOFT FROM 6KM ON UP BUT DO NOT BELIEVE WITH SUCH
LOW CAPE VALUES THAT WE WILL SEE ANY SVR WEATHER. ANY STORM THAT
CAN REACH THESE HIGHER ALTITUDES LIKELY WILL GET SHEARED OUT
ANYWAY. SO JUST HAVE CHC POPS FOR LATER IN THE DAY INTO THE
AFTERNOON.
SHOWERS AND THUNDERSTORMS WILL WANE QUICKLY THIS EVENING AS THIS
NEXT SHORTWAVE SHEARS OUT IN THIS EVER PRESENT CONFLUENT ZONE
OVERHEAD TONIGHT. THIS OCCURS COINCIDENT WITH THE LOSS OF THE
DAY/S HEATING. FURTHERMORE WITH STRGR UPPER CONFLUENCE...A SFC
RIDGE WILL FORM OVER THE REGION...LEADING TO SOME POTENTIAL
CLEARING. WILL MONITOR FOR POTENTIAL VALLEY FOG LATE TONIGHT WITH
SHORT TERM UPDATE COMING SOON.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
TUESDAY WILL BEGIN WITH SCT-BKN MID-HI CLDS ARND AS A STRUNG OUT
FRONTL SYSTEM IS STALLED OFFSHORE WITH A DEPARTING SFC WAVE. THE
CMC AND NAM ARE STRONGEST WITH THE SFC WAVE DEVELOPMENT WITH THE
EURO AND GFS MUCH MORE WEAKER FLATTER WITH THE PRESSURE FIELD
OFFSHORE. THIS MAKES A DIFFERENCE FOR OUR AREA IN THAT THE NAM AND
CMC HAVE A STRONGER LL HIGH PRESSURE SYSTEM OVER OUR AREA TUESDAY
WHICH TENDS TO SUPRESS CONVECTIVE DEVELOPMENT. THE NAM MODEL
SOUNDINGS FOR TUESDAY DON/T PRODUCE ANY SIGNIFICANT CAPE AND APPEAR
CAPPED TO SOME EXTENT BY A MID-LVL INVERSION. THE EURO AND GFS
HAVE A WEAKER SFC PRESSURE RDG OVER OUR AREA WITH MORE LOW-LEVEL
MOISTURE HANGING ARND. THE GFS SOUNDINGS DO GENERATE CAPE WITH THE
AFTERNOON HEATING SUGGESTIVE OF ISLD TO SCT SHRA AND EVEN SOME
TSRA. LI/S ARE SLIGHTLY NEGATIVE ON THE GFS WITH CAPES IN THE
HUNDREDS AGAIN....MAINLY FROM THE SRN TIER INTO NRN PA. SO NOTHING
MAJOR. WIND SHEARS ARE WEAK AND CAPE IS NOT IMPRESSIVE SO WILL
HAVE ISLD TO SCT SHRA AND TSRA WITH HIGHEST POPS IN NE PA AND
LOWER POPS AS YOU TRAVEL N INTO NC NY WHERE CAPE IS MINIMAL.
FOR TUESDAY NIGHT...ALL CONVECTIVE ACVTY WINDS DOWN WITH LOSS OF
DAY/S HEATING. SFC HIGH PRESSURE DOMINATES ON ALL MODELS AND THERE
IS LARGE SCALE SUBSC. SO WILL WIND DOWN ANY RESIDUAL POPS FROM THE
EARLY EVENING.
FOR WEDNESDAY AND WEDNESDAY NIGHT...HIGH PRESSURE TAKES CONTROL WITH
LARGE SCALE SUBSC AND MORE STBL AIR IN PLACE. SO WED CUD BE THE
NICEST DAY OF THIS FORECAST PD.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
4 AM MON UPDATE... OVERALL...A QUIET PD STILL LOOKS TO BE IN THE
OFFING FOR NY/PA...AS THE LATEST EC/GFS AND ASSOCD ENSEMBLE MEANS
CONTINUE TO INDICATE THAT A FLAT UPR-LVL TROUGH AXIS ACRS THE ERN
CONUS WILL FURTHER DE-AMPLIFY WITH TIME. IN FACT...THE LATEST
RUNS NOW ACTUALLY INDICATE A NARROW RIDGE AXIS DEVELOPING BY LATER
NEXT WEEKEND.
AT THE SFC...THE MAIN BAROCLINIC ZNS/FRNTS MOSTLY STAY SITUATED
WELL TO OUR S THROUGH THE SRN MID-ATL...AND ALSO UPSTREAM THROUGH
SRN CANADA AND THE NRN LKS RGN. TWDS NEXT SUN/MON...THE LATTER
SYSTEM MAY TRY TO EDGE CLOSE ENOUGH TO BRING ISOLD DIURNALLY DRIVEN
CONVECTION. FOR NOW...THE SCHC POPS WE HAVE IN THERE WILL SUFFICE.
TEMPS SHOULD UNDERGO A GRADUAL WARMING TREND UNDER RISING HGTS
ALOFT...WITH DAILY HIGHS MAINLY IN THE 80S BY NEXT WEEKEND.
PREV DISC... SUBTLE FEATURES WILL INFLUENCE THE WX IN THE LONG
TERM AS THE SFC RDGG BRKS DOWN EARLY IN THE PD. OPERATIONAL MODELS
SHOW A WEAK FNTL BNDRY TRYING TO DROP SOUTH FROM CANADA FRI INTO
SAT BEFORE EVENTUALLY WASHING OUT OVER THE AREA. WITH HTG...THIS
MAY BE ENUF LL CONV TO DVLP ISLTD AFTN CONV FRI AND SAT.
TEMPS WILL SHOW A GRADUAL RECOVERY THRU THE PD...RCHG ABV NRML BY
FRI AND SAT. STILL DFRNCS BETWEEN HPC GUID AND GFS GENERATED
MEX...SO BLENDED GUID WITH PRVS FCST TO CONT A SLOW UPWARD TREND.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
12Z MON UPDATE... MAINLY VFR SHOULD PREVAIL TIL MIDDAY (15-17Z).
THIS AFTN...CONDS SHOULD LWR TO MVFR...AS SHRA BECOME MORE
WIDESPREAD...JUST AHEAD OF A WEAK COLD FRNT.
THIS EVE...CONDS SHOULD GRADUALLY IMPROVE TO VFR FROM NW TO
SE...AS THE FRNT EASES ACRS THE RGN.
S TO SW SFC WINDS TDY...WILL BECOME LGT AND VRBL TNT.
OUTLOOK...
TUE...MOSTLY VFR...WITH BRIEF RESTRICTIONS PSBL IN THE AFTN FROM
ISOLD SHRA/TSRA.
WED/THU/FRI...MAINLY VFR. MRNG VLY FOG PSBL WITH IFR AT KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...
LONG TERM...DGM/MLJ
AVIATION...MLJ/RRM
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
630 AM EDT MON AUG 20 2012
.SYNOPSIS...
A SERIES OF DISTURBANCES ALOFT PASSING INTO TUESDAY. WEAK HIGH
PRESSURE FOR WEDNESDAY THROUGH THE END OF THE WORK WEEK PROVIDES
GRADUAL WARMING TREND.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE PARADE OF MID LEVEL/UPPER LEVEL DISTURBANCES JUST KEEPS MARCHING
ON. ONE STRETCHED OUT VORT MAX AT 500 MB STILL DEPICTED BY RAP FM
NR MGW TO N OF CRW BY DAWN THIS MORNING. WILL HOLD ONTO SOME SLIGHT
CHANCE POPS ACROSS NORTH CENTRAL WV INTO THE CENTRAL MOUNTAINS.
OTHERWISE...MORE TYPICAL AUGUST FOG OR LOW STRATUS CLOUDS WILL GREET
THE MONDAY DAWN.
THE BEST FIT/MATCH BETWEEN THE AVAILABLE MOISTURE...THE COOLING
TEMPERATURES ALOFT...AND THE MID LEVEL VORT MAXIMUMS SEEM TO
BE OVER EASTERN OHIO AND INTO NORTHERN/NORTHWESTERN WEST VIRGINIA
THIS AFTERNOON INTO THIS EVENING. THE EQUILIBRIUM LEVEL IS ABOUT 3
TO 4 TSHD FT HIGHER ACROSS THE NORTH COMPARED TO THE SOUTH...
REACHING AROUND 28/29 THOUSAND IN THE NORTH. SO TALL/COLD AUGUST
CONVECTION IS NOT EXPECTED HOWEVER...WITH THE FREEZING LEVEL LOWER
THAN NORMAL...AROUND 10 THSD FT...SOME LOCALIZED HAIL IS
POSSIBLE...DESPITE THE RELATIVELY LOW EL FOR AUGUST.
SO RAISED POPS INTO THE 40 PERCENT RANGE ACROSS THE NORTH...WITH
20/30 POPS FURTHER SOUTH. WILL LINGER THOSE POPS WELL INTO THE
EVENING.
WILL NOT GET TOO FANCY WITH THE LATE NIGHT FOG FOR MONDAY
NIGHT...SINCE IT WILL DEPEND ON THE RAIN COVERAGE. YET...PLACES
LIKE THE COOL MOUNTAIN VALLEYS SHOULD GO DOWN AGAIN.
NO BIG CHANGES ON TEMPERATURES. WAS THINKING TODAY SHOULD BE NO
WARMER...BUT MAYBE A FEW DEGREES COOLER THAN SUNDAY.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
500MB TROUGH AXIS EXPECTED TO PUSH THROUGH TUESDAY INTO WEDNESDAY.
WITH SOME LINGERING LOW TO MID LEVEL MOISTURE...HAVE SLIGHT CHANCE
TO CHANCE POPS ACROSS FORECAST AREA TUESDAY INTO TUESDAY NIGHT.
FOLLOWING TROUGH PASSAGE...SETTLE INTO WEAK FLOW ALOFT WITH A
SURFACE HIGH BUILDING IN TO PROVIDE MAINLY DRY WEATHER. WITH THAT
SAID...COULD STILL SEE SOME ISOLATED SHOWERS OR THUNDERSTORMS IN THE
MOUNTAINS...MAINLY ON WEDNESDAY AFTERNOON. WILL SEE A GRADUAL
WARMING TREND THROUGH MID-WEEK AS HEIGHTS RISE AND WE SEE PLENTY OF
SUNSHINE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
USED A BLEND OF THE GEFS MEAN...ECMWF AND ECMWF MEAN. THIS LEAVES A
WEAK HIGH PRESSURE SYSTEM OVER THE REGION FOR THURSDAY AND FRIDAY...
BUT POSSIBLY ENOUGH MOISTURE TO FIRE SOME AFTERNOON
SHOWERS/THUNDERSTORMS IN THE MOUNTAINS. BY THE WEEKEND...A SOUTHERLY
FLOW IN ADVANCE OF AN APPROACHING SYSTEM MAY PROVIDE ENOUGH
MOISTURE FOR SHOWERS OR THUNDERSTORMS THROUGHOUT THE REGION.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
A MIX OF VALLEY FOG AND STRATUS...MAINLY IN WV...LIFTING 12Z TO
14Z. WITH THE LATER SUNRISES...SOME LOCAL IFR COULD LINGER THROUGH
13Z.
HAVE CLOUDS AT 3 TO 5 THSD FT AGL BECOMING SCATTERED TO BROKEN BY
15Z NORTH AND 17Z SOUTH.
WITH THE COMBINATION OF THE COOLER MID LEVEL TEMPERATURES AND A BIT
MORE MOISTURE...WENT A BIT HIGHER ON POPS FOR THIS AFTERNOON INTO
THIS EVENING ACROSS EASTERN OHIO AND NORTHERN WEST VIRGINIA THAN
PREVIOUSLY...AND ALSO HIGHER THAN COUNTIES FURTHER TO THE SOUTH.
SCATTERED SHOWERS SHOULD BE PREVALENT...BUT WITH EQUILIBRIUM LEVELS
AROUND 25 THSD...ALSO SOME THUNDER.
HAVE CONVECTION WEAKENING 00Z TO 02Z TUESDAY...AND THEN
AGAIN...ANOTHER FOG ISSUE/HEADACHE BY 06Z TUESDAY. FIGURING LOCAL
IFR FORMING AROUND 06Z IN THE MOUNTAIN VALLEYS THEN SPREADING INTO
SOME OF THE WESTERN LOWLANDS INCLUDING CRW 06Z TO 12Z TUESDAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: LESS COVERAGE TO THE AFTERNOON SHOWERS THAN
FORECAST. FORMATION AND AREAL COVERAGE OF FOG AGAIN AN ISSUE FOR
OVERNIGHT MONDAY NIGHT. COVERAGE COULD BE MORE OR LESS THAN
FORECAST...DEPENDING ON COVERAGE OF EARLIER SHOWERS AND LINGERING
CLOUDS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18
CRW CONSISTENCY L L L H H H H H H H H H
HTS CONSISTENCY L L H H H H H H H H H H
BKW CONSISTENCY M M M M H H H M H H H H
EKN CONSISTENCY L L H H H H H H H H H H
PKB CONSISTENCY L L L H H H H H H H H H
CKB CONSISTENCY L M H H H H H H H H H H
AFTER 12Z TUESDAY...
BRIEF IFR CONDITIONS POSSIBLE IN THUNDERSTORMS TUESDAY AFTERNOON.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB
SHORT TERM...MZ
LONG TERM...RPY
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1030 AM EDT MON AUG 20 2012
.SYNOPSIS...
A COLD FRONT WILL SLOWLY SLIDE EAST OF THE SOUTHERN APPALACHIAN
REGION ON TUESDAY. WEAK HIGH PRESSURE WILL BUILD OVER THE WESTERN
CAROLINAS AND NORTHEAST GEORGIA BY MID WEEK AND REMAIN THROUGH THIS
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM EDT...MADE A FEW CHANGES FOR THE MORNING UPDATE. LOW
LEVEL CLOUD COVER IS HANGING TOUGH ACROSS THE ERN ZONES AND
ACCOUNTED FOR THIS IN THE SKY GRIDS. THE 13Z SFC ANALYSIS SHOWS THE
STATIONARY FRONT ACROSS THE MIDLANDS WITH A MESO LOW LOCATED ACROSS
ERN NC...WHICH REMAINS THE MAIN FOCUSING MECHANISM FOR PRECIP.
THUS...POPS HAVE BEEN TAKEN OUT OF THE ERN ZONES FOR LATE MORNING
AND EARLY AFTERNOON. EXPECT SCT GENERAL CONVECTION THIS
AFTERNOON...A FEW IN THE MTNS...BUT MOST ACTIVITY TO THE SOUTH AND
EAST. THE UPPER JET MAX CONTINUES TO SHIFT NE OF THE AREA...SO A
LESS DYNAMICAL SETUP IS IN STORE AND SBCAPE VALUES WILL BE LOW END.
DEEP BULK SHEAR WILL BE HIGH...BUT EFFECTIVE SHEAR LOW TO MODERATE.
SO...NOT ANTICIPATING ANY REAL CONCERNS WITH SVR CONVECTION THIS
AFTERNOON. MAX TEMPS WERE ADJ DOWN A DEGREE OR TWO ACROSS THE ERN
HALF OF THE CWFA TO ACCOUNT FOR THE OPAQUE CLOUD COVER.
AS OF 520 AM EDT...RAIN CONTINUES ACROSS THE I-77 CORRIDOR...THOUGH
THE BACK EDGE OF THE PCPN CONTINUES TO SLOWLY MOVE EAST. UPPED POPS
FOR A FEW MORE HOURS TO ACCOUNT FOR THE BACK EDGE OF THE FRONTAL
BAND PCPN. ALSO CUT BACK ON FOG A LITTLE OUT INTO THE PIEDMONT WHERE
MID LEVEL CLOUDS PROBABLY WON/T CLEAR UNTIL AFTER SUNRISE.
PREVIOUS DISCUSSION...
RAIN IS BECOMING MORE WIDESPREAD OVER THE SRN UPSTATE AND NC
PIEDMONT THOUGH THE AREA OF PCPN IS STILL EXHIBITING A GRADUAL PUSH
TO THE EAST. IT APPEARS THAT THE SHORT WAVE ERN TN...EVIDENT IN
DRYING IN THE WATER VAPOR IMAGERY...IS HELPING TO ENHANCE UPPER
DIVERGENCE IN THE ENTRANCE REGION OF THE JET. THE HRRR HAS PICKED UP
ON THIS AREA OF PCPN AND IS ALSO SHOWING A SLOW EASTWARD MOVEMENT.
THEREFORE...THE PCPN SHOULD GRADUALLY CLEAR THE EASTERN ZONES BY
SUNRISE. ACROSS THE MOUNTAINS AND FOOTHILLS AREAS OF DENSE FOG WILL
LIKELY DEVELOP AS THE UPPER LEVEL SUBSIDENCE PUSHES INTO THE WRN
ZONES. AGEOSTROPHIC FLOW ORIENTED FROM THE NW ON THE SUBSIDENCE SIDE
OF THE JET IS CONTRIBUTING TO SOME MIXING AND DRY AIR ADVECTION
ACROSS THE FRENCH BROAD VALLEY. I SUSPECT THIS WILL WEAKEN AS THE
WAVE PUSHES TO THE EAST AND FOG SHOULD SET UP EVEN IN THE LARGE
VALLEYS SOON.
LATER TODAY THE SFC FRONT...WHICH HAS NOW MOVED INTO THE SRN PART OF
THE UPSTATE...WILL LIFT BACK TO THE NORTH. THIS SHOULD RESULT IN
GOOD LLVL CONVERGENCE ROUGHLY ALONG THE I-85 CORRIDOR AND I SUSPECT
THAT SCT LATE AFTN AND EVENING TSTMS WILL DEVELOP IN THIS AREA.
CONVECTION MAY LAST A WAYS INTO THE OVERNIGHT PERIOD AS THE NAM
SHOWS IMPROVING LLVL CONVERGENCE THIS EVENING WITH THE FRONT
BECOMING MORE DEFINED. OVER THE MTNS LOWER DEWPOINT AIR BEHIND THE
BNDRY WILL RESULT IN A PLEASANTLY COOL NIGHT WITH LOWS FALLING INTO
THE LOWER TO MID 50S IN MANY LOCATIONS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 230 AM MONDAY...ON TUESDAY...THE MID LEVEL TROF AXIS IS
EXPECTED TO RUN ACROSS THE OHIO RIVER AND MISSISSIPPI RIVER VALLEYS
DURING THE AFTERNOON. THE GFS AND ECMWF INDICATES THAT THE REGION
EAST OF THE TROF WILL SEE AN IMPRESSIVE LATE SUMMER JET...WITH A
LONG BAND OF UPPER DIVERGENCE ALONG AND WEST OF THE ATLANTIC COAST.
HIGH TEMPERATURES IN THE MID 80S AND DEWPOINTS IN THE L60S SHOULD
YIELD WEAK TO MODERATE AFTERNOON INSTABILITY. THE COMBINATION OF THE
UPPER FORCING AND INSTABILITY SHOULD SUPPORT SCT
SHRA/TSRA...ESPECIALLY EAST OF I-85. CONVECTION SHOULD DISSIPATE
THROUGH THE EVENING HOURS...BUT ISOLATED COVERAGE COULD CONTINUE
ACROSS THE PIEDMONT INTO EARLY WED MORNING. LOW TEMPERATURES ARE
FORECAST TO RANGE FROM THE U50S ACROSS THE MTNS VALLEYS TO THE MID
60S EAST.
ON WEDNESDAY...THE H5 TROF AXIS WILL MOVE OVER THE SOUTHERN
APPALACHIAN REGION DURING THE AFTERNOON. A VORT MAX WITHIN THE TROF
AXIS WILL LIKELY RIPPLE OVER THE MTNS DURING THE LATE AFTERNOON.
HIGH TEMPERATURES MAY RANGE A DEGREE OR TWO WARMER THAN TUESDAY WITH
DEWPOINTS IN THE LOWER TO MID 60S. GFS CAPE VALUES SHOULD ARE
FORECAST TO RANGE AROUND 1000 J/KG. BASED ON WEAK DIURNAL
INSTABILITY AND THE APPROACH OF A WEAK MID LEVEL DISTURBANCE I WILL
FORECAST A DIURNAL SCHC ACROSS THE CWA...WITH CHC POPS ACROSS THE
HIGHEST ELEVATIONS. CONVECTION SHOULD COME TO AN END DURING THE LATE
EVENING. WEDNESDAY NIGHT IS FORECAST TO REMAIN DRY...CALM...AND MIN
TEMPS AROUND 3-5 DEGREES BELOW NORMAL.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 245 AM MONDAY...WEAK MID LEVEL RIDGING WILL BUILD OVER THE
REGION THURSDAY THROUGH SUNDAY. AT THE SFC...BROAD HIGH PRESSURE
CENTERED OVER THE MID ATLANTIC STATES WILL RIDGE SW ACROSS THE CWA
THROUGH THE PERIOD. TEMPERATURES EACH AFTERNOON IS EXPECTED TO RANGE
FROM NEAR 80 ACROSS THE MTNS VALLEYS TO THE MID 80S EAST. DEWPOINTS
WILL ALSO RANGE IN THE 60S EACH AFTERNOON...YIELDING WEAK TO
MODERATE INSTABILITY. DIURNAL ISO TO CHC CONVECTION IS EXPECTED EACH
DAY...WITH COVERAGE FAVORED OVER THE HIGH TERRAIN.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
AT KCLT...A SFC COLD FRONT HAS DROPPED WELL SOUTH OF THE AIRFIELD
OVERNIGHT. A BKN IFR CIG DEVELOPED BEHIND THE FRONT...THOUGH
PERIODS OF LIGHT TO MODERATE RAIN HAVE BRIEFLY LIFTED THE CIG. WITH
THE RAIN HAVING ENDED...EXPECT THE IFR CIG TO LAST UNTIL 13
UTC...AND POSSIBLE AS LONG AS 14 UTC THOUGH THE DECK DOESN/T APPEAR
TO BE VERY DEEP. THEREAFTER THE CIGS SHOULD QUICKLY LIFT INTO THE
VFR RANGE BY LATE MORNING. LIGHT NE WINDS THIS MORNING WILL
GRADUALLY TURN OUT OF THE SW THIS AFTN AS THE FRONT RETURNS NORTH.
SCT SHRA/TSTMS WILL DEVELOP ALONG THE FRONT. HOWEVER...THE
CONVECTION LOOKS TOO ISOLATED TO CARRY ANYTHING MORE THAN PROB30
RIGHT NOW. DRIER AIR FILTERS IN TONIGHT AND NOT RESTRICTIONS ARE
EXPECTED.
KAVL...A SFC COLD FRONT HAS MOVED MOVED DOWN INTO THE MIDLANDS.
DRIER AIR FILTERED INTO THE FRENCH BROAD VALLEY AND HAS KEPT
CONDITIONS PRETTY GOOD AT KAVL MOST OF THE NIGHT. HOWEVER...THERE
APPEARS TO BE PLENTY OF STRATUS AND FOG JUST A LITTLE WAYS UP AND
DOWN THE FRENCH BROAD VALLEY...SO A PERIOD OF LIFR RESTRICTIONS IS
STILL POSSIBLE TIL 13 UTC. NOT EXPECTING ENUF CONVECTION OVER THE
MTNS TO MENTION IN THE TAF. THERE WILL BE VALLEY FOG AGAIN
TONIGHT...BUT PROBABLY NOT AT KAVL.
ELSEWHERE...PATCHY IFR TO LIFR CIGS WILL MAINLY BE CONFINED TO AREAS
SOUTH OF THE UPSTATE TAF SITES EARLY THIS MORNING. KHKY HOWEVER
SHOULD SEE A THIN IFR DECK UNTIL AROUND 13 UTC.
OTHERWISE...CONDITIONS SHOULD IMPROVE QUICKLY THIS MORNING ONCE
MIXING STARTS. LIGHT NE WINDS WILL TURN OUT OF THE SW IN THE AFTN
HOURS AS A SFC BNDRY MOVES BACK IN FROM THE SOUTH. SCT SHRA/TSTMS
WILL DEVELOP ALONG THE FRONT...BUT NOT ENUF TO CARRY MORE THAN A
PROB30 OR VCTS AT ANY OF THE UPSTATE TAF SITES.
OUTLOOK...A WEAK STATIONARY BOUNDARY WILL LINGER ACROSS THE REGION
THROUGH THE EARLY WEEK. SFC LOWS MAY TRACK ALONG THE
FRONT...SUPPORTING PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH
TUESDAY. IN ADDITION...THE FORMATION OF LOW CLOUDS AND FOG IS
POSSIBLE EACH MORNING...ESPECIALLY NEAR AREAS OF RECENT RAINFALL.
CONDITIONS SHOULD IMPROVE WED AND THU.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...NED
NEAR TERM...MCAVOY/SBK
SHORT TERM...NED
LONG TERM...NED
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
740 AM EDT MON AUG 20 2012
.SYNOPSIS...
A COLD FRONT WILL SLOWLY SLIDE EAST OF THE SOUTHERN APPALACHIAN
REGION ON TUESDAY. WEAK HIGH PRESSURE WILL BUILD OVER THE WESTERN
CAROLINAS AND NORTHEAST GEORGIA BY MID WEEK AND REMAIN THROUGH THIS
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 520 AM EDT...RAIN CONTINUES ACROSS THE I-77 CORRIDOR...THOUGH
THE BACK EDGE OF THE PCPN CONTINUES TO SLOWLY MOVE EAST. UPPED POPS
FOR A FEW MORE HOURS TO ACCOUNT FOR THE BACK EDGE OF THE FRONTAL
BAND PCPN. ALSO CUT BACK ON FOG A LITTLE OUT INTO THE PIEDMONT WHERE
MID LEVEL CLOUDS PROBABLY WON/T CLEAR UNTIL AFTER SUNRISE.
PREVIOUS DISCUSSION...
RAIN IS BECOMING MORE WIDESPREAD OVER THE SRN UPSTATE AND NC
PIEDMONT THOUGH THE AREA OF PCPN IS STILL EXHIBITING A GRADUAL PUSH
TO THE EAST. IT APPEARS THAT THE SHORT WAVE ERN TN...EVIDENT IN
DRYING IN THE WATER VAPOR IMAGERY...IS HELPING TO ENHANCE UPPER
DIVERGENCE IN THE ENTRANCE REGION OF THE JET. THE HRRR HAS PICKED UP
ON THIS AREA OF PCPN AND IS ALSO SHOWING A SLOW EASTWARD MOVEMENT.
THEREFORE...THE PCPN SHOULD GRADUALLY CLEAR THE EASTERN ZONES BY
SUNRISE. ACROSS THE MOUNTAINS AND FOOTHILLS AREAS OF DENSE FOG WILL
LIKELY DEVELOP AS THE UPPER LEVEL SUBSIDENCE PUSHES INTO THE WRN
ZONES. AGEOSTROPHIC FLOW ORIENTED FROM THE NW ON THE SUBSIDENCE SIDE
OF THE JET IS CONTRIBUTING TO SOME MIXING AND DRY AIR ADVECTION
ACROSS THE FRENCH BROAD VALLEY. I SUSPECT THIS WILL WEAKEN AS THE
WAVE PUSHES TO THE EAST AND FOG SHOULD SET UP EVEN IN THE LARGE
VALLEYS SOON.
LATER TODAY THE SFC FRONT...WHICH HAS NOW MOVED INTO THE SRN PART OF
THE UPSTATE...WILL LIFT BACK TO THE NORTH. THIS SHOULD RESULT IN
GOOD LLVL CONVERGENCE ROUGHLY ALONG THE I-85 CORRIDOR AND I SUSPECT
THAT SCT LATE AFTN AND EVENING TSTMS WILL DEVELOP IN THIS AREA.
CONVECTION MAY LAST A WAYS INTO THE OVERNIGHT PERIOD AS THE NAM
SHOWS IMPROVING LLVL CONVERGENCE THIS EVENING WITH THE FRONT
BECOMING MORE DEFINED. OVER THE MTNS LOWER DEWPOINT AIR BEHIND THE
BNDRY WILL RESULT IN A PLEASANTLY COOL NIGHT WITH LOWS FALLING INTO
THE LOWER TO MID 50S IN MANY LOCATIONS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 230 AM MONDAY...ON TUESDAY...THE MID LEVEL TROF AXIS IS
EXPECTED TO RUN ACROSS THE OHIO RIVER AND MISSISSIPPI RIVER VALLEYS
DURING THE AFTERNOON. THE GFS AND ECMWF INDICATES THAT THE REGION
EAST OF THE TROF WILL SEE AN IMPRESSIVE LATE SUMMER JET...WITH A
LONG BAND OF UPPER DIVERGENCE ALONG AND WEST OF THE ATLANTIC COAST.
HIGH TEMPERATURES IN THE MID 80S AND DEWPOINTS IN THE L60S SHOULD
YIELD WEAK TO MODERATE AFTERNOON INSTABILITY. THE COMBINATION OF THE
UPPER FORCING AND INSTABILITY SHOULD SUPPORT SCT
SHRA/TSRA...ESPECIALLY EAST OF I-85. CONVECTION SHOULD DISSIPATE
THROUGH THE EVENING HOURS...BUT ISOLATED COVERAGE COULD CONTINUE
ACROSS THE PIEDMONT INTO EARLY WED MORNING. LOW TEMPERATURES ARE
FORECAST TO RANGE FROM THE U50S ACROSS THE MTNS VALLEYS TO THE MID
60S EAST.
ON WEDNESDAY...THE H5 TROF AXIS WILL MOVE OVER THE SOUTHERN
APPALACHIAN REGION DURING THE AFTERNOON. A VORT MAX WITHIN THE TROF
AXIS WILL LIKELY RIPPLE OVER THE MTNS DURING THE LATE AFTERNOON.
HIGH TEMPERATURES MAY RANGE A DEGREE OR TWO WARMER THAN TUESDAY WITH
DEWPOINTS IN THE LOWER TO MID 60S. GFS CAPE VALUES SHOULD ARE
FORECAST TO RANGE AROUND 1000 J/KG. BASED ON WEAK DIURNAL
INSTABILITY AND THE APPROACH OF A WEAK MID LEVEL DISTURBANCE I WILL
FORECAST A DIURNAL SCHC ACROSS THE CWA...WITH CHC POPS ACROSS THE
HIGHEST ELEVATIONS. CONVECTION SHOULD COME TO AN END DURING THE LATE
EVENING. WEDNESDAY NIGHT IS FORECAST TO REMAIN DRY...CALM...AND MIN
TEMPS AROUND 3-5 DEGREES BELOW NORMAL.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 245 AM MONDAY...WEAK MID LEVEL RIDGING WILL BUILD OVER THE
REGION THURSDAY THROUGH SUNDAY. AT THE SFC...BROAD HIGH PRESSURE
CENTERED OVER THE MID ATLANTIC STATES WILL RIDGE SW ACROSS THE CWA
THROUGH THE PERIOD. TEMPERATURES EACH AFTERNOON IS EXPECTED TO RANGE
FROM NEAR 80 ACROSS THE MTNS VALLEYS TO THE MID 80S EAST. DEWPOINTS
WILL ALSO RANGE IN THE 60S EACH AFTERNOON...YIELDING WEAK TO
MODERATE INSTABILITY. DIURNAL ISO TO CHC CONVECTION IS EXPECTED EACH
DAY...WITH COVERAGE FAVORED OVER THE HIGH TERRAIN.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AT KCLT...A SFC COLD FRONT HAS DROPPED WELL SOUTH OF THE AIRFIELD
OVERNIGHT. A BKN IFR CIG DEVELOPED BEHIND THE FRONT...THOUGH
PERIODS OF LIGHT TO MODERATE RAIN HAVE BRIEFLY LIFTED THE CIG. WITH
THE RAIN HAVING ENDED...EXPECT THE IFR CIG TO LAST UNTIL 13
UTC...AND POSSIBLE AS LONG AS 14 UTC THOUGH THE DECK DOESN/T APPEAR
TO BE VERY DEEP. THEREAFTER THE CIGS SHOULD QUICKLY LIFT INTO THE
VFR RANGE BY LATE MORNING. LIGHT NE WINDS THIS MORNING WILL
GRADUALLY TURN OUT OF THE SW THIS AFTN AS THE FRONT RETURNS NORTH.
SCT SHRA/TSTMS WILL DEVELOP ALONG THE FRONT. HOWEVER...THE
CONVECTION LOOKS TOO ISOLATED TO CARRY ANYTHING MORE THAN PROB30
RIGHT NOW. DRIER AIR FILTERS IN TONIGHT AND NOT RESTRICTIONS ARE
EXPECTED.
KAVL...A SFC COLD FRONT HAS MOVED MOVED DOWN INTO THE MIDLANDS.
DRIER AIR FILTERED INTO THE FRENCH BROAD VALLEY AND HAS KEPT
CONDITIONS PRETTY GOOD AT KAVL MOST OF THE NIGHT. HOWEVER...THERE
APPEARS TO BE PLENTY OF STRATUS AND FOG JUST A LITTLE WAYS UP AND
DOWN THE FRENCH BROAD VALLEY...SO A PERIOD OF LIFR RESTRICTIONS IS
STILL POSSIBLE TIL 13 UTC. NOT EXPECTING ENUF CONVECTION OVER THE
MTNS TO MENTION IN THE TAF. THERE WILL BE VALLEY FOG AGAIN
TONIGHT...BUT PROBABLY NOT AT KAVL.
ELSEWHERE...PATCHY IFR TO LIFR CIGS WILL MAINLY BE CONFINED TO AREAS
SOUTH OF THE UPSTATE TAF SITES EARLY THIS MORNING. KHKY HOWEVER
SHOULD SEE A THIN IFR DECK UNTIL AROUND 13 UTC.
OTHERWISE...CONDITIONS SHOULD IMPROVE QUICKLY THIS MORNING ONCE
MIXING STARTS. LIGHT NE WINDS WILL TURN OUT OF THE SW IN THE AFTN
HOURS AS A SFC BNDRY MOVES BACK IN FROM THE SOUTH. SCT SHRA/TSTMS
WILL DEVELOP ALONG THE FRONT...BUT NOT ENUF TO CARRY MORE THAN A
PROB30 OR VCTS AT ANY OF THE UPSTATE TAF SITES.
OUTLOOK...A WEAK STATIONARY BOUNDARY WILL LINGER ACROSS THE REGION
THROUGH THE EARLY WEEK. SFC LOWS MAY TRACK ALONG THE
FRONT...SUPPORTING PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH
TUESDAY. IN ADDITION...THE FORMATION OF LOW CLOUDS AND FOG IS
POSSIBLE EACH MORNING...ESPECIALLY NEAR AREAS OF RECENT RAINFALL.
CONDITIONS SHOULD IMPROVE WED AND THU.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...NED
NEAR TERM...MCAVOY
SHORT TERM...NED
LONG TERM...NED
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1101 AM CDT MON AUG 20 2012
.DISCUSSION...
SKIES ARE SUNNY ACROSS THE MIDSOUTH THIS MORNING. DEWPOINTS ARE
MOSTLY IN THE 50S WITH TEMPS IN THE 70S. A MID LEVEL TROF WILL
SLOWLY PUSH ACROSS THE AREA TODAY. MOISTURE IS VERY LIMITED SO
JUST EXPECT SOME HIGH BASED CU THIS AFTERNOON THOUGH CANNOT RULE
OUT A SHOWER OR TWO. THE HRRR IS KICKING OUT SOME ISOLD SHOWERS
ACROSS WESTERN PARTS FOR THE MIDSOUTH THOUGH IT SEEMS A LITTLE
OVERDONE CONSIDERING THE DRY AIRMASS IN PLACE. ONGOING FORECAST
LOOKS GOOD WITH NO CHANGES NEEDED ATTM.
SJM
&&
.PREV DISCUSSION... /ISSUED 418 AM CDT MON AUG 20 2012/
UPPER LEVEL NORTHWESTERLY FLOW WILL GRADUALLY WEAKEN THROUGH THE
WEEK...AS A BROAD UPPER LEVEL HEIGHT RIDGE EXPANDS EASTWARD FROM
THE SOUTHERN PLAINS. THIS UPPER RIDGE WILL REMAIN CENTERED OVER
TEXAS...WITH SOME WEAKNESSES IN THE RIDGE DEPICTED BY THE GFS AND
ECMWF LATE IN THE WEEK. THE 00Z RUNS OF BOTH MODELS ARE HAVE MOVED
TOWARD A DRIER WEEKEND FOR THE MIDSOUTH... WITH SLIGHTLY STRONGER
UPPER RIDGING...AND A WEAKER SHEAR AXIS PLACED FURTHER WEST OVER
MO/AR/LA. MODEST LOW LEVEL MOISTURE RETURN MAY BE INSUFFICIENT TO
OVERCOME WARMING MIDLEVEL TEMPS...AND IT APPEARS CONVECTIVE
INHIBITION MAY BE STRONGER THIS WEEKEND THAN PREVIOUSLY
ANTICIPATED.
IN THE INTERIM... A DRY MIDCONTINENTAL AIRMASS WILL BE OVERSPREAD
BY MIDLEVEL CLOUDS TODAY. THE DEPARTURE OF THESE CLOUDS WILL PLAY
A LARGE ROLE ON SURFACE TEMPS. CLOUDS SHOULD BE LESS PREVALENT
ON TUESDAY AND WEDNESDAY...AS THE MAIN MIDLEVEL MOISTURE FETCH
SHIFTS EASTWARD TO THE CAROLINAS...AHEAD OF A PROGRESSIVE AND
WEAKENING UPPER LEVEL TROF.
GFS MOS TEMPS GENERALLY ON TARGET...BUT HAVE BUMPED MIDWEEK TEMPS
A DEGREE OR TWO...GIVEN THE DRY AIRMASS AND SUNNY SKIES.
PWB
&&
.AVIATION...
12Z TAF SET
VFR CONDITIONS ARE EXPECTED TO CONTINUE OVER NEXT 24 HOURS. CAN/T RULE
OUT A SHRA OR TWO DEVELOPING OVER NE MS THIS AFTERNOON BUT NOT
ENOUGH CONFIDENCE TO MENTION AT KTUP. LIGHT WINDS...MAINLY N TO
NE...WILL OCCUR THROUGH THE PERIOD.
KRM
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 89 64 89 65 / 10 10 10 0
MKL 86 57 89 58 / 10 10 10 0
JBR 85 59 89 59 / 10 10 0 0
TUP 85 61 88 61 / 10 10 10 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1150 AM EDT MON AUG 20 2012
.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN JUST TO OUR SOUTH THROUGH TUESDAY.
MEANWHILE...A COUPLE OF WEAK UPPER LEVEL DISTURBANCES WILL PASS
ACROSS OUR REGION FROM THE WEST ON MONDAY AND AGAIN ON TUESDAY.
THIS WILL HELP REDEVELOP SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS OVER OUR REGION ON BOTH DAYS. BY MID WEEK THE FRONT
WILL MOVE OFF THE ATLANTIC COAST...ALLOWING HIGH PRESSURE TO BUILD
INTO THE REGION FROM THE WEST AND REDUCING THE CHANCES FOR SHOWERS
AND STORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1140 AM EDT MONDAY...
REGIONAL WSR-88D LOOP SHOWED WIDELY SCATTERED SHOWERS DEVELOPING
ACROSS THE MOUNTAINS WITH BEST COVERAGE ACROSS THE NORTHWEST
MOUNTAINS. MADE SOME ADJUSTMENTS IN POPS AND TEMPERATURES FOR
THIS AFTERNOON.
AS OF 950 AM EDT MONDAY...
THE LOW CENTER ALONG THE FRONTAL BOUNDARY TO OUR SOUTH WILL LIFT
NORTHEAST AWAY FROM OUR CWA. THE ASSOCIATED SHOWERS WITH THIS
FEATURE WILL MOVE EAST OUT OF OUR REGION. PATCHY LOW CLOUDS AND
FOG ARE LIFTING AND MIXING OUT THIS MORNING. ADJUSTED POPS WITH
CURRENT RADAR TRENDS. MADE SOME MINOR ADJUSTMENTS IN CLOUDS AND
TEMPERATURES FOR LATE MORNING INTO THIS AFTERNOON. HRRR AND
WRFARW-RNK SUPPORT SCATTERED CONVECTION IN THE THIS AFTERNOON
FORECAST WITH UPPER LEVEL TROF. WILL HOLD WITH HIGH TEMPERATURES IN
THE LOWER 70S IN THE MOUNTAINS TO AROUND 80 DEGREES.
AS OF 625 AM EDT MONDAY...
UPDATE TO REMOVE SLIGHT CHC POPS FROM WEST REMAINDER OF THIS
MORNING AND SHOW TIGHTER GRADIENT IN POPS ACROSS THE
SOUTHEAST...WITH CHC POPS LINGERING FAR SOUTHEAST UNTIL 10AM.
ADJUSTED SKY AND FOG GRIDS SLIGHTLY AS WELL PER LATEST SATELLITE
AND OBSERVATIONS. MORE CLEARING OCCURING IN PARTS OF FAR WEST WITH
EXCEPTION OF SOME STRATUS ALONG A FEW WESTERN SLOPES.
PREV DISCUSSION AS OF 415 AM EDT MONDAY...
A SERIES OF UPPER LEVEL WAVES CONTINUE TO RIDE ALONG AND JUST
NORTH OF A WEAK FRONTAL BOUNDARY DRAPED ACROSS THE CAROLINAS EARLY
THIS MORNING...WITH ONE CURRENTLY HELPING TO DEVELOP AN AREA OF
MORE WIDESPREAD MODERATE RAINFALL ACROSS CENTRAL NC...COMING CLOSE
TO CLIPPING OUR FAR SOUTHEASTERN COUNTIES THROUGH THE PREDAWN
HOURS. ANY SHOWERS DOWN IN THIS REGION WITH THIS WAVE WILL MOVE
EAST OF THE AREA DURING THE MORNING...WHILE AREAS OF MAINLY VALLEY FOG
BACK IN THE WEST WHERE THERE IS PARTIAL CLEARING QUICKLY
DISSIPATING WITH SUN. BY AFTERNOON...ANOTHER WEAK WAVE SLIDES
ACROSS FROM THE WEST...AND THIS SHOULD HELP DEVELOP MORE
SCATTERED SHOWERS. COVERAGE SOMEWHAT LIMITED WITH DRIER AIR ALOFT
AND INSTABILITY QUITE SHALLOW IN BOTH NAM AND GFS FCST
SOUNDINGS...SO DOWNPLAYED THUNDER CHANCES. MAY BE BETTER IN FAR
EAST BY LATE AFT AND THIS EVENING...BEFORE THESE SHOWERS FINALLY
PULL EAST OF THE REGION WHILE ALSO DISSIPATING LATE THIS EVENING.
AFTER MIDNIGHT DROP POPS EXCEPT FOR LINGFERING SLIGHT CHC FAR EAST
CLOSER TO THE LINGERING FRONTAL BOUNDARY. WIND LIGHT AND
DIRECTIONS TRICKY WITH WESTERLY PROBABLY IN WEST AND MAYBE PERIOD
OF LIGHT NORTHERLY OR EASTERLY IN EAST IF SHOWERS ARE CONTINUING
JUST TO OUR EAST...AND IF EVEN SOME LIGHT MIXING CAN TAKE PLACE IN
THE EAST...MAY EVENTUALLY SEE LIGHT WESTERLY THERE...BUT WENT
PRETTY CLOSE TO CALM GIVEN GRADIENT AND UNCERTAINTY.
TEMPERATURE WISE...CERTAINLY BEST TO GO WITH COOLER MET GUIDANCE
IN EAST WHERE BROKEN TO OVERCAST CLOUD COVER SHOULD BE PREVALENT
ALL DAY...AND WHILE THERE MAY BE BRIEF PERIODS OF SUN IN THE
WEST...THIS LIKELY TO FILL BACK IN WITH BROKEN CU DECK
QUICKLY...SO PRUDENT TO STICK WITH SLIGHTLY COOLER MET GUIDANCE
THERE AS WELL. MID 70S WEST TO NEAR 80 EAST. OVERNIGHT...MILDER
MET GUIDANCE IN EAST WITH MORE CLOUDS AND LINGERING SHOWERS...BUT
IN WEST MAY GET SOME CLEARING AGAIN SO LEANED A BIT MORE TOWARD
COOLER MAV THERE. MAY BE VALLEY FOG AGAIN DEPENDING ON DEGREE OF
CLEARING...BUT LEFT OUT OF GRIDS FOR NOW PENDING ADDITIONAL
RAINFALL DURING THE DAY TODAY AND GETTING BETTER HANDLE ON DEGREE
OF CLEARING.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
AS OF 330 AM EDT MONDAY...
STARTING THE DAY ON TUESDAY...THE LARGE UPPER LEVEL TROUGH
STRETCHING FROM SOUTHERN CANADA TO THE GULF COAST WILL BE THE
DOMINANT FEATURE IN OUR WEATHER PATTERN...WITH MODELS IN GOOD
AGREEMENT THAT A DECENT SHORTWAVE TROUGH WILL BE ENTERING THE LOWER
OHIO RIVER VALLEY FROM THE UPPER MIDWEST. IN THE LOWER LEVELS...WE
CAN EXPECT TO FIND BROAD BUT WEAK HIGH PRESSURE SITUATED ACROSS THE
LOWER GREAT LAKES INTO THE APPALACHIANS...WHILE A STATIONARY FRONT
WILL REMAIN SITUATED ALONG THE COASTAL SOUTHEAST. SHOWER ACTIVITY
WILL START THE MORNING ISOLATED...BUT WILL BECOME MORE SCATTERED BY
AFTERNOON... WITH A FEW THUNDERSTORMS DEVELOPING...AS DAYTIME
HEATING INCREASES AND THE SHORTWAVE APPROACHES OUR AREA. RAINFALL
WILL DIMINISH DURING THE EVENING AS DAYTIME HEATING ENDS.
THE SHORTWAVE WILL PASS ACROSS OUR AREA TUESDAY NIGHT INTO WEDNESDAY
AFTERNOON...AND WILL DEVELOP A WAVE ALONG THE STATIONARY FRONT THAT
WILL ULTIMATELY PUSH THE BOUNDARY FURTHER OUT TO SEA TOWARD THE END
OF THE WORKWEEK. AFTER THAT...THE LARGE SCALE TROUGHING PATTERN WILL
BEGIN TO FLATTEN OUT ACROSS THE EAST...RESULTING IN A MORE ZONAL
FLOW. AS SUCH...WILL SEE MORE OF SHOWERS AND A FEW THUNDERSTORMS
DEVELOP ON WEDNESDAY AND THURSDAY AFTERNOONS...BUT EXPECT COVERAGE
TO REMAIN ONLY ISOLATED TO WIDELY SCATTERED. THEREFORE...KEPT THE
RAIN CHANCES AROUND 20 PERCENT BOTH DAYS.
WITH THE SHORTWAVE APPROACHING THE AREA ON TUESDAY...HELPING TO
ENHANCE THE CLOUD COVER AND RAINFALL...EXPECT HIGH TEMPERATURES TO
REMAIN 3 TO 5 DEGREES BELOW NORMAL FOR THE SECOND HALF OF AUGUST. AS
THE UPPER LEVEL PATTERN TRENDS MORE ZONAL ON WEDNESDAY AND THURSDAY
HOWEVER...WE CAN EXPECT TEMPERATURES VERY CLOSE TO NORMAL AREAWIDE.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 400 PM EDT SUNDAY...
MODEL SOLUTIONS MIXED FOR THE LATTER HALF OF THE WEEK WITH GREATEST
ENSEMBLE SPREAD NEXT WEEKEND. THE GENERAL IDEA HOWEVER SEEMS TO BE A
WEAK MEAN TROF OVER THE ERN CONUS...IN SPITE OF ITS WEAKENING
EARLIER IN THE WEEK. THIS SUGGESTS ANY SHORTWAVE ENERGY WHICH
ARRIVES FROM SYSTEMS PASSING THROUGH SRN CANADA AND THE NRN CONUS
WILL HAVE A CHANCE TO AMPLIFY AS THEY PROGRESS EAST BOUND INTO THE
UPPER LEVEL TROF. THIS IMPLIES WEATHER ACROSS OUR REGION WILL
REMAIN ACTIVE WITH AT LEAST CHC SHRA/TSRA DURING THE PERIOD...MAINLY
DIURNALLY DRIVEN THURSDAY AND FRIDAY...BUT POTENTIALLY MORE
WIDESPREAD FOR NEXT WEEKEND PENDING AMPLIFICATION OF ANY OF THE
SHORTWAVES THAT MOVE DOWNSTREAM FROM THE UPPER MID WEST.
WITH WEAKENING OF THE EASTERN TROF...TRENDED TEMPERATURES UPWARD
CLOSER TO THE SEASONAL NORMS.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
AS OF 750 AM EDT MONDAY...
PATCHY FOG FORMING WHERE MID CLOUDS HAVE VACATED AND MOVED
EAST...AND SOME AIRPORTS COMING IN AND OUT OF IFR OR MVFR. LWB
ONLY SITE WHERE LIFR FOG WILL LINGER UNTIL 13 TO 14Z...ELSEWHERE
ANY MVFR WILL QUICKLY LIFT. ANY LINGERING SPRINKLES VCNTY OF DAN
THIS MORNING WILL SLIDE EAST BUT CONDITIONS WILL REMAIN VFR THERE.
OTHERWISE...A VERY WEAK DISTURBANCE A VERY WEAK DISTURBANCE WILL
KEEP A SMALL CHANCE OF SCATTERED SHOWERS AND THUNDERSTORMS IN THE
FORECAST DURING THE AFTERNOON AND EARLY EVENING HOURS MONDAY BUT
NOT EXPECTING COVERAGE TO BE HIGH ENOUGH TO INCLUDE MENTION OF
THUNDER OR PRECIP IN TAF LOCATIONS. IF ANY SHWRS OR BRIEF THUNDER
DOES IMPACT AN AIRPORT TODAY...IT WILL MOST LIKELY BE 18Z-22Z FOR
LWB/BLF/BCB...AND 20-03Z FOR ROA/LYH/DAN. THUNDER NOT VERY LIKELY
GIVEN SHALLOW INSTABILITY.
WINDS BASICALLY LIGHT AND VARIABLE...BUT WITH MIXING THIS AFTERNOON
WILL TEND TO HAVE A WESTERLY COMPONENT...EXPECIALLY IN THE WEST.
EAST A LITTLE TRICKIER...WITH POSSIBLE NORTHEASTERLY COMPONENT
INITIALLY...THEN MAYBE WEST LATE. STILL 5KT OR LESS.
WITH PARTIAL CLEARING AGAIN PRIMARILY IN THE WEST
OVERNIGHT...PATCHY FOG WITH IFR CONDITIONS AGAIN POSSIBLE AT LWB
ESPECIALLY...BCB ANF BLF MORE LIKELY MVFR OR ONLY VERY BRIEF IFR.
VFR MOST LIKELY EAST...UNLESS HEAVIER SHOWERS IMPACT A PARTICULAR
AIRPORT AFT/EVE...THEN MVFR TO IFR FOG MAY BE POSSIBLE TOWARD
MORNING. INCLUDED BRIEF PERIOD OF MVFR FOG AT LYH FOR NOW. MUCH
DEPENDS ON DEGREE OF CLEARING...WHICH IS LESS LIKELY AT DAN.
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE AGAIN ON
TUESDAY...WITH ISOLATED AND BRIEF MVFR/IFR CONDITIONS ARE
POSSIBLE. BY WEDNESDAY THE COLD FRONT CONTINUES TO MOVE FURTHER TO
OUR EAST. HIGH PRESSURE WILL THEN BUILD IN FOR THE REMAINDER OF
THE PERIOD...WITH MAINLY VFR/MVFR CONDITIONS EXPECTED AND VERY
LITTLE OR NOW CHANCE OF SHOWERS OR STORMS DEVELOPING.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...KK
NEAR TERM...KK/SK
SHORT TERM...NF
LONG TERM...PM
AVIATION...CF/SK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1002 AM EDT MON AUG 20 2012
.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN JUST TO OUR SOUTH THROUGH TUESDAY.
MEANWHILE...A COUPLE OF WEAK UPPER LEVEL DISTURBANCES WILL PASS
ACROSS OUR REGION FROM THE WEST ON MONDAY AND AGAIN ON TUESDAY.
THIS WILL HELP REDEVELOP SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS OVER OUR REGION ON BOTH DAYS. BY MID WEEK THE FRONT
WILL MOVE OFF THE ATLANTIC COAST...ALLOWING HIGH PRESSURE TO BUILD
INTO THE REGION FROM THE WEST AND REDUCING THE CHANCES FOR SHOWERS
AND STORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 950 AM EDT MONDAY...
THE LOW CENTER ALONG THE FRONTAL BOUNDARY TO OUR SOUTH WILL LIFT
NORTHEAST AWAY FROM OUR CWA. THE ASSOCIATED SHOWERS WITH THIS
FEATURE WILL MOVE EAST OUT OF OUR REGION. PATCHY LOW CLOUDS AND
FOG ARE LIFTING AND MIXING OUT THIS MORNING. ADJUSTED POPS WITH
CURRENT RADAR TRENDS. MADE SOME MINOR ADJUSTMENTS IN CLOUDS AND
TEMPERATURES FOR LATE MORNING INTO THIS AFTERNOON. HRRR AND
WRFARW-RNK SUPPORT SCATTERED CONVECTION IN THE THIS AFTERNOON
FORECAST WITH UPPER LEVEL TROF. WILL HOLD WITH HIGH TEMPERATURES IN
THE LOWER 70S IN THE MOUNTAINS TO AROUND 80 DEGREES.
AS OF 625 AM EDT MONDAY...
UPDATE TO REMOVE SLIGHT CHC POPS FROM WEST REMAINDER OF THIS
MORNING AND SHOW TIGHTER GRADIENT IN POPS ACROSS THE
SOUTHEAST...WITH CHC POPS LINGERING FAR SOUTHEAST UNTIL 10AM.
ADJUSTED SKY AND FOG GRIDS SLIGHTLY AS WELL PER LATEST SATELLITE
AND OBSERVATIONS. MORE CLEARING OCCURING IN PARTS OF FAR WEST WITH
EXCEPTION OF SOME STRATUS ALONG A FEW WESTERN SLOPES.
PREV DISCUSSION AS OF 415 AM EDT MONDAY...
A SERIES OF UPPER LEVEL WAVES CONTINUE TO RIDE ALONG AND JUST
NORTH OF A WEAK FRONTAL BOUNDARY DRAPED ACROSS THE CAROLINAS EARLY
THIS MORNING...WITH ONE CURRENTLY HELPING TO DEVELOP AN AREA OF
MORE WIDESPREAD MODERATE RAINFALL ACROSS CENTRAL NC...COMING CLOSE
TO CLIPPING OUR FAR SOUTHEASTERN COUNTIES THROUGH THE PREDAWN
HOURS. ANY SHOWERS DOWN IN THIS REGION WITH THIS WAVE WILL MOVE
EAST OF THE AREA DURING THE MORNING...WHILE AREAS OF MAINLY VALLEY FOG
BACK IN THE WEST WHERE THERE IS PARTIAL CLEARING QUICKLY
DISSIPATING WITH SUN. BY AFTERNOON...ANOTHER WEAK WAVE SLIDES
ACROSS FROM THE WEST...AND THIS SHOULD HELP DEVELOP MORE
SCATTERED SHOWERS. COVERAGE SOMEWHAT LIMITED WITH DRIER AIR ALOFT
AND INSTABILITY QUITE SHALLOW IN BOTH NAM AND GFS FCST
SOUNDINGS...SO DOWNPLAYED THUNDER CHANCES. MAY BE BETTER IN FAR
EAST BY LATE AFT AND THIS EVENING...BEFORE THESE SHOWERS FINALLY
PULL EAST OF THE REGION WHILE ALSO DISSIPATING LATE THIS EVENING.
AFTER MIDNIGHT DROP POPS EXCEPT FOR LINGFERING SLIGHT CHC FAR EAST
CLOSER TO THE LINGERING FRONTAL BOUNDARY. WIND LIGHT AND
DIRECTIONS TRICKY WITH WESTERLY PROBABLY IN WEST AND MAYBE PERIOD
OF LIGHT NORTHERLY OR EASTERLY IN EAST IF SHOWERS ARE CONTINUING
JUST TO OUR EAST...AND IF EVEN SOME LIGHT MIXING CAN TAKE PLACE IN
THE EAST...MAY EVENTUALLY SEE LIGHT WESTERLY THERE...BUT WENT
PRETTY CLOSE TO CALM GIVEN GRADIENT AND UNCERTAINTY.
TEMPERATURE WISE...CERTAINLY BEST TO GO WITH COOLER MET GUIDANCE
IN EAST WHERE BROKEN TO OVERCAST CLOUD COVER SHOULD BE PREVALENT
ALL DAY...AND WHILE THERE MAY BE BRIEF PERIODS OF SUN IN THE
WEST...THIS LIKELY TO FILL BACK IN WITH BROKEN CU DECK
QUICKLY...SO PRUDENT TO STICK WITH SLIGHTLY COOLER MET GUIDANCE
THERE AS WELL. MID 70S WEST TO NEAR 80 EAST. OVERNIGHT...MILDER
MET GUIDANCE IN EAST WITH MORE CLOUDS AND LINGERING SHOWERS...BUT
IN WEST MAY GET SOME CLEARING AGAIN SO LEANED A BIT MORE TOWARD
COOLER MAV THERE. MAY BE VALLEY FOG AGAIN DEPENDING ON DEGREE OF
CLEARING...BUT LEFT OUT OF GRIDS FOR NOW PENDING ADDITIONAL
RAINFALL DURING THE DAY TODAY AND GETTING BETTER HANDLE ON DEGREE
OF CLEARING.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
AS OF 330 AM EDT MONDAY...
STARTING THE DAY ON TUESDAY...THE LARGE UPPER LEVEL TROUGH
STRETCHING FROM SOUTHERN CANADA TO THE GULF COAST WILL BE THE
DOMINANT FEATURE IN OUR WEATHER PATTERN...WITH MODELS IN GOOD
AGREEMENT THAT A DECENT SHORTWAVE TROUGH WILL BE ENTERING THE LOWER
OHIO RIVER VALLEY FROM THE UPPER MIDWEST. IN THE LOWER LEVELS...WE
CAN EXPECT TO FIND BROAD BUT WEAK HIGH PRESSURE SITUATED ACROSS THE
LOWER GREAT LAKES INTO THE APPALACHIANS...WHILE A STATIONARY FRONT
WILL REMAIN SITUATED ALONG THE COASTAL SOUTHEAST. SHOWER ACTIVITY
WILL START THE MORNING ISOLATED...BUT WILL BECOME MORE SCATTERED BY
AFTERNOON... WITH A FEW THUNDERSTORMS DEVELOPING...AS DAYTIME
HEATING INCREASES AND THE SHORTWAVE APPROACHES OUR AREA. RAINFALL
WILL DIMINISH DURING THE EVENING AS DAYTIME HEATING ENDS.
THE SHORTWAVE WILL PASS ACROSS OUR AREA TUESDAY NIGHT INTO WEDNESDAY
AFTERNOON...AND WILL DEVELOP A WAVE ALONG THE STATIONARY FRONT THAT
WILL ULTIMATELY PUSH THE BOUNDARY FURTHER OUT TO SEA TOWARD THE END
OF THE WORKWEEK. AFTER THAT...THE LARGE SCALE TROUGHING PATTERN WILL
BEGIN TO FLATTEN OUT ACROSS THE EAST...RESULTING IN A MORE ZONAL
FLOW. AS SUCH...WILL SEE MORE OF SHOWERS AND A FEW THUNDERSTORMS
DEVELOP ON WEDNESDAY AND THURSDAY AFTERNOONS...BUT EXPECT COVERAGE
TO REMAIN ONLY ISOLATED TO WIDELY SCATTERED. THEREFORE...KEPT THE
RAIN CHANCES AROUND 20 PERCENT BOTH DAYS.
WITH THE SHORTWAVE APPROACHING THE AREA ON TUESDAY...HELPING TO
ENHANCE THE CLOUD COVER AND RAINFALL...EXPECT HIGH TEMPERATURES TO
REMAIN 3 TO 5 DEGREES BELOW NORMAL FOR THE SECOND HALF OF AUGUST. AS
THE UPPER LEVEL PATTERN TRENDS MORE ZONAL ON WEDNESDAY AND THURSDAY
HOWEVER...WE CAN EXPECT TEMPERATURES VERY CLOSE TO NORMAL AREAWIDE.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 400 PM EDT SUNDAY...
MODEL SOLUTIONS MIXED FOR THE LATTER HALF OF THE WEEK WITH GREATEST
ENSEMBLE SPREAD NEXT WEEKEND. THE GENERAL IDEA HOWEVER SEEMS TO BE A
WEAK MEAN TROF OVER THE ERN CONUS...IN SPITE OF ITS WEAKENING
EARLIER IN THE WEEK. THIS SUGGESTS ANY SHORTWAVE ENERGY WHICH
ARRIVES FROM SYSTEMS PASSING THROUGH SRN CANADA AND THE NRN CONUS
WILL HAVE A CHANCE TO AMPLIFY AS THEY PROGRESS EAST BOUND INTO THE
UPPER LEVEL TROF. THIS IMPLIES WEATHER ACROSS OUR REGION WILL
REMAIN ACTIVE WITH AT LEAST CHC SHRA/TSRA DURING THE PERIOD...MAINLY
DIURNALLY DRIVEN THURSDAY AND FRIDAY...BUT POTENTIALLY MORE
WIDESPREAD FOR NEXT WEEKEND PENDING AMPLIFICATION OF ANY OF THE
SHORTWAVES THAT MOVE DOWNSTREAM FROM THE UPPER MID WEST.
WITH WEAKENING OF THE EASTERN TROF...TRENDED TEMPERATURES UPWARD
CLOSER TO THE SEASONAL NORMS.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
AS OF 750 AM EDT MONDAY...
PATCHY FOG FORMING WHERE MID CLOUDS HAVE VACATED AND MOVED
EAST...AND SOME AIRPORTS COMING IN AND OUT OF IFR OR MVFR. LWB
ONLY SITE WHERE LIFR FOG WILL LINGER UNTIL 13 TO 14Z...ELSEWHERE
ANY MVFR WILL QUICKLY LIFT. ANY LINGERING SPRINKLES VCNTY OF DAN
THIS MORNING WILL SLIDE EAST BUT CONDITIONS WILL REMAIN VFR THERE.
OTHERWISE...A VERY WEAK DISTURBANCE A VERY WEAK DISTURBANCE WILL
KEEP A SMALL CHANCE OF SCATTERED SHOWERS AND THUNDERSTORMS IN THE
FORECAST DURING THE AFTERNOON AND EARLY EVENING HOURS MONDAY BUT
NOT EXPECTING COVERAGE TO BE HIGH ENOUGH TO INCLUDE MENTION OF
THUNDER OR PRECIP IN TAF LOCATIONS. IF ANY SHWRS OR BRIEF THUNDER
DOES IMPACT AN AIRPORT TODAY...IT WILL MOST LIKELY BE 18Z-22Z FOR
LWB/BLF/BCB...AND 20-03Z FOR ROA/LYH/DAN. THUNDER NOT VERY LIKELY
GIVEN SHALLOW INSTABILITY.
WINDS BASICALLY LIGHT AND VARIABLE...BUT WITH MIXING THIS AFTERNOON
WILL TEND TO HAVE A WESTERLY COMPONENT...EXPECIALLY IN THE WEST.
EAST A LITTLE TRICKIER...WITH POSSIBLE NORTHEASTERLY COMPONENT
INITIALLY...THEN MAYBE WEST LATE. STILL 5KT OR LESS.
WITH PARTIAL CLEARING AGAIN PRIMARILY IN THE WEST
OVERNIGHT...PATCHY FOG WITH IFR CONDITIONS AGAIN POSSIBLE AT LWB
ESPECIALLY...BCB ANF BLF MORE LIKELY MVFR OR ONLY VERY BRIEF IFR.
VFR MOST LIKELY EAST...UNLESS HEAVIER SHOWERS IMPACT A PARTICULAR
AIRPORT AFT/EVE...THEN MVFR TO IFR FOG MAY BE POSSIBLE TOWARD
MORNING. INCLUDED BRIEF PERIOD OF MVFR FOG AT LYH FOR NOW. MUCH
DEPENDS ON DEGREE OF CLEARING...WHICH IS LESS LIKELY AT DAN.
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE AGAIN ON
TUESDAY...WITH ISOLATED AND BRIEF MVFR/IFR CONDITIONS ARE
POSSIBLE. BY WEDNESDAY THE COLD FRONT CONTINUES TO MOVE FURTHER TO
OUR EAST. HIGH PRESSURE WILL THEN BUILD IN FOR THE REMAINDER OF
THE PERIOD...WITH MAINLY VFR/MVFR CONDITIONS EXPECTED AND VERY
LITTLE OR NOW CHANCE OF SHOWERS OR STORMS DEVELOPING.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...KK
NEAR TERM...KK/SK
SHORT TERM...NF
LONG TERM...PM
AVIATION...CF/SK
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1031 AM MDT MON AUG 20 2012
.UPDATE...LATEST SATELLITE IMAGERY SHOWS CONSIDERABLE MID/HIGH
LEVEL CLOUDINESS PUSHING EAST ACROSS COLORADO. THERE HAVE BEEN A
FEW LIGHT SHOWERS AND SPRINKLES NOTED ACROSS WESTERN
COLORADO...WHICH WILL REACH OUR FORECAST AREA THIS AFTERNOON. WITH
ALL THE CLOUD COVER INSTABILITY WILL BE LIMITED SO ACTIVITY WILL
LIKELY BE SCATTERED SHOWERS AND ONLY ISOLATED THUNDERSTORMS IN THE
HIGH COUNTRY. STILL A THREAT OF ISOLATED SHOWERS/STORMS ON THE
PLAINS BUT CLOUD COVER AND SLOW MOISTURE RETURN ON THE PLAINS IS
LIMITING OUR INSTABILITY AS WELL.
&&
.AVIATION...CURRENT FORECAST IS GOOD WITH ONLY SMALL THREAT OF
SHOWERS. CHANCE FOR GUSTY WINDS IS HIGHER THOUGH WITH SHOWER
OUTFLOWS FROM ANY CONVECTION SPILLING OFF THE FOOTHILLS. BEST
CHANCE WOULD BE 21Z-01Z. HRRR LOOKS TOO EARLY GIVEN AMOUNT OF
MID/HIGH LEVEL CLOUDINESS AND SLOW WARMUP.
&&
.HYDROLOGY...NO THREAT OF FLOODING WITH WEAK INSTABILITY...LACK OF
WARM CLOUD DEPTH...AND FAST SHOWER/STORM MOTION OF 20-25 MPH.
&&
.PREV DISCUSSION... /ISSUED 325 AM MDT MON AUG 20 2012/
SHORT TERM...WATER VAPOR IMAGERY SHOWING A WELL DEFINED SHORT
WAVE OVER IDAHO AT THIS TIME. THIS WAVE WILL MOVE SOUTHEAST TODAY
IN THE NORTHWEST FLOW ALOFT AND CLIP NORTHEAST COLORADO. MID AND
HIGH CLOUDS WILL CONTINUE TO INCREASE AHEAD OF IT THIS MORNING.
NOT MUCH IN THE WAY OF LOW LEVEL MOISTURE FOR THIS SYSTEM TO WORK
WITH. PRECIPITABLE WATER VALUES WILL BE AROUND HALF INCH OVER THE
HIGHER TERRAIN TO THREE-QUARTERS OF AN INCH ALONG THE FRONT RANGE.
SHOULD BE ENOUGH LIFT WITH THIS SYSTEM TO TRIGGER SCATTERED
SHOWERS AND THUNDERSTORMS OVER THE HIGHER TERRAIN. DUE TO THE
LIMITED MOISTURE...RAINFALL AMOUNTS WILL BE ON THE LIGHT SIDE. AS
THIS SYSTEM MOVES ACROSS THE FRONT RANGE...ONLY EXPECT A FEW HIGH
BASED SHOWERS AND THUNDERSTORMS DUE TO THE DRY LOWER LEVELS. WILL
SEE A BETTER CHANCE FOR CONVECTION OVER THE PLAINS WHERE DEW
POINTS WILL CLIMB INTO THE 40S.
AIRMASS WILL COOL OVER THE MOUNTAINS AND BE ABOUT THE AS YESTERDAY
OVER NORTHEAST COLORADO. TEMPERATURES WILL BE THE SAME OR SLIGHTLY
COOLER THAN YESTERDAY. EVEN THOUGH TEMPERATURES WILL START OFF
WARMER...CLOUD COVER WILL SLOW HEATING THIS AFTER. THE EXCEPTION
WILL BE OVER NORTHEAST CORNER OF COLORADO WHERE MORE SUN MAY LEAD
TO WARMER TEMPERATURES.
THIS SYSTEM WILL EXIT THE AREA TONIGHT...MOST OF THE SHOWERS AND
STORMS SHOULD END EARLY IN THE EVENING...THOUGH A FEW MAY LINGER
AFTER MIDNIGHT OVER EASTERN COLORADO. SKIES WILL CLEAR AND BY
TUESDAY MORNING MOSTLY CLEAR SKIES WILL PREVAIL.
LONG TERM...DRIER AIR IN NW FLOW ALOFT WILL SPREAD ACROSS THE
AREA ON TUE ALTHOUGH DECENT LOW LVL MOISTURE WILL BE OVER THE FAR
ERN PLAINS. BELIEVE CAPPING INVERSION WILL SUPPRESS CONVECTION
OVER THE ERN PLAINS SO WILL KEEP FCST DRY. HIGHS ON TUE WILL
RISE INTO THE UPPER 80S TO LOWER 90S ACROSS NERN CO BASED ON
LATEST 850-700 MB TEMPS.
FOR WED APPEARS A WK DISTURBANCE IS STILL FCST TO MOVE ACROSS NRN
CO AS THE FLOW ALOFT BECOMES MORE WLY. APPEARS THERE WILL BE SOME
INCREASE IN SUBTROPICAL MOISTURE AS WELL SO WILL CONTINUE WITH SCT
POPS IN THE MTNS WITH A SLIGHT CHC ELSEWHERE. ONCE AGAIN DEEPER
LOW LVL MOISTURE AND BETTER INSTABILITY IS FCST OVER THE FAR ERN
PLAINS SO COULD SEE A BETTER CHC FOR STRONGER STORMS IN THIS AREA.
AS FOR TEMPS LATEST 850-700 TEMPS ARE A FEW DEGREES WARMER WHICH
WOULD LEAD TO READINGS IN THE LOWER TO MID 90S ACROSS NERN CO
UNLESS MID LVL CLOUD COVER SPREADS ACROSS THE AREA BY MIDDAY.
BY THU AN UPPER LEVEL RIDGE WILL BUILD INTO THE AREA HOWEVER
LATEST ECMWF AND GFS STILL SHOW SOME LINGERING SUBTROPICAL
MOISTURE SO WILL KEEP LOW POPS IN THE MTNS. OVER THE PLAINS DECENT
INSTABILITY IS STILL SHOWN OVER THE FAR ERN PLAINS SO WILL MENTION
SOME LOW POPS IN THIS AREA AS WELL. HIGHS ON THU MAY COOL A FEW
DEGREES HOWEVER READINGS WILL STILL REMAIN AROUND 5 DEGREES ABV
NORMAL.
FOR FRI THERE STILL REMAIN SOME DIFFERENCES BETWEEN THE ECMWF AND
GFS. THE ECMWF CONTINUES TO SHOW A MORE ORGANIZED UPPER LEVEL
TROUGH MOVING ACROSS THE AREA WHILE THE GFS IS MORE DISORGANIZED
AND KEEPS MAIN ENERGY OVER SRN CO. AT THIS POINT STILL HARD TO SAY
WHICH SOLUTION IS BEST. NATURALLY IF THE ECMWF IS RIGHT THERE WILL
BE A BETTER CHC FOR TSTMS ON FRI WHILE THE GFS WOULD HAVE THE BEST
CHC FOR CONVECTION MAINLY OVER SRN COLORADO. FOR NOW WILL JUST
MENTION A SLIGHT CHC FOR STORMS. HIGHS ON FRI LOOK SIMILAR TO THU
BASED ON LATEST 850-700 MB TEMPS.
BY NEXT WEEKEND A STRONGER UPPER LEVEL TROUGH IS SUPPOSED TO MOVE
ACROSS THE NRN ROCKIES WITH DRIER WLY FLOW ACROSS NRN COLORADO.
THUS WILL ONLY MENTION A SLIGHT CHC OF STORMS MAINLY OVER THE
HIGHER TERRAIN. HIGHS BOTH DAYS WILL STILL REMAIN FM 5 TO 7
DEGREES ABV NORMAL.
AVIATION...AN UPPER LEVEL SYSTEM WILL BRING MID AND HIGH CLOUDS
TO THE AREA TODAY. CEILINGS ARE EXPECTED TO REMAIN ABOVE 8000 FEET
TODAY. A FEW SHOWERS OR STORMS MAY MOVE OFF THE HIGHER TERRAIN AND
ACROSS THE DENVER AREA. THIS ACTIVITY IS EXPECTED TO BE WEAK...BUT
MAY PRODUCE WIND GUSTS TO 35 KNOTS.
HYDROLOGY... SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP
TODAY. MOISTURE IS NOT THAT HIGH...SO WOULD EXPECT MODERATE TO
PERHAPS BRIEFLY HEAVY RAIN FROM THE THUNDERSTORMS. THE SHOWERS AND
STORMS WILL MOVE AT A GOOD CLIP TODAY...KEEPING THE THREAT FOR
HEAVY RAIN IS LOW.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....RPK
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
607 PM EDT MON AUG 20 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 347 PM EDT MON AUG 20 2012
UPPER TROUGHING OVER THE REGION WILL GRADUALLY DEPART TONIGHT INTO
EARLY TOMORROW...AND RIDGING AT THE SURFACE WILL REASSERT
DOMINANCE FOR MUCH OF THE REMAINDER OF THE FORECAST PERIOD...WITH
WEAK QUASI ZONAL FLOW ALOFT BECOMING MORE ANTICYCLONIC LATER IN
THE WEEK. TEMPERATURES WILL GRADUALLY WARM BACK TO NEAR OR JUST
ABOVE NORMAL VALUES THIS WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 607 PM EDT MON AUG 20 2012
QUICK UPDATE WITH RESPECT TO CONVECTIVE COVERAGE ACROSS THE FORECAST
AREA EARLY THIS EVENING IN VICINITY OF THE UPPER LEVEL WAVE.
COVERAGE ACROSS THE NORTHERN WABASH VALLEY IS GREATER THAN
ISOLATED...AND HRRR GUIDANCE HINTING AT THIS ACTIVITY TO CONTINUE
MOVING EAST ACROSS FAR NORTHERN COUNTIES OVER THE NEXT FEW HOURS
BEFORE DIMINISHING. HAVE THEREFORE BUMPED UP TO SCATTERED POPS IN
THE NORTHERN COUNTIES THROUGH 01Z...WITH ISOLATED WORDING CONTINUING
ELSEWHERE. CONVECTION WILL BEGIN TO DIMINISH TOWARDS SUNSET AS
HEATING IS LOST AND WAVE SHIFTS EAST.
REST OF FORECAST UNCHANGED....PREVIOUS DISCUSSION FOLLOWS BELOW.
FOCUS IS ON ENDING OF THUNDERSTORMS. GUIDANCE IS SIMILAR AND A
BLEND IS USED.
ISOLATED THUNDERSTORMS ARE DEVELOPING...BUT STRUGGLING IN A WEAKLY
FORCED ENVIRONMENT. ONLY THUNDERSTORMS OVER NORTHEAST ILLINOIS AND
NORTHWEST INDIANA...AIDED IN PART BY CONVERGENCE ALONG THE LAKE
BREEZE...ARE MAINTAINING ANY KIND OF SIGNIFICANT COVERAGE. THESE
MAY MANAGE TO PERSIST TO NEAR 00Z...BUT EXPECT THAT MOST ALL
CONVECTION WILL BE DONE BY THE START OF THE OVERNIGHT PERIOD...SO
WILL CARRY NO POPS AFTER 00Z.
ON TEMPS...PREFER NUMBERS JUST ABOVE CONSENSUS...NEAR
PERSISTENCE...AS THERE HAS BEEN LITTLE CHANGE IN THE AIRMASS FROM
YESTERDAY/LAST NIGHT. THIS AGREES FAIRLY WELL WITH LOW LEVEL
THICKNESSES...YIELDING LOW TO MID 50S AGAIN TONIGHT.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 347 PM EDT MON AUG 20 2012
FOCUS IS MAINLY TEMPS THROUGHOUT AS HIGH PRESSURE REASSERTS
ITSELF. GUIDANCE IS SIMILAR AND A BLEND IS USED.
GUIDANCE SUGGESTS ONE FINAL WEAK WAVE MAY BE DEPARTING THE AREA
EARLY TOMORROW...BUT AS IT SHOULD BE GONE BY PEAK HEATING...EXPECT
NO CONVECTIVE DEVELOPMENT OVER THE AREA BEYOND CUMULUS...AND WILL
KEEP DRY FORECAST. AS SURFACE HIGH BUILDS IN...THIS WILL CONTINUE
THROUGH THE REMAINDER OF THE SHORT TERM.
ON TEMPS...LOW LEVEL THICKNESSES RISE GRADUALLY THROUGHOUT THE
SHORT TERM...AND A STEADY WARMING TREND IS DEPICTED. NEAR TO JUST
ABOVE CONSENSUS NUMBERS DEPICT THIS WELL AND THIS WAS THE GENERAL
MAX/MIN TEMP TECHNIQUE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ISSUED AT 142 PM EDT MON AUG 20 2012
FOCUS FOR THE EXTENDED WILL BE TEMPERATURES AND WHETHER OR NOT TO
MENTION ANY POPS.
MODELS IN GOOD AGREEMENT ON SOUTH AND SOUTHWEST LOW LEVEL FLOW AS
SURFACE HIGH PRESSURE BECOMES ANCHORED ACROSS THE EASTERN STATES.
THE RESULT WILL BE SLIGHTLY ABOVE NORMAL TEMPERATURES AND INCREASING
HUMIDITY. HOWEVER...THE MAIN COLD FRONT SHOULD BE FAR ENOUGH TO THE
NORTHWEST MONDAY TO BE A FACTOR...AND WITH DEEP MOISTURE
ABSENT...WILL HOLD OFF ON POPS AT THIS TIME...EVEN THOUGH LOW
COVERAGE THUNDERSTORMS WOULD NOT BE OUT OF THE REALM OF POSSIBILITY.
FELT THE CENTRAL REGIONAL INITIALIZATION TEMPERATURES LOOKED FINE.
&&
.AVIATION /DISCUSSION FOR THE 202100Z KIND TAF UPDATE/...
ISSUED AT 421 PM EDT MON AUG 20 2012
SCATTERED CONVECTION CURRENTLY ACROSS NORTHERN INDIANA INTO EASTERN
ILLINOIS...ASSOCIATED WITH AN UPPER WAVE DROPPING SOUTHEAST THROUGH
THE MIDWEST. DOESN/T APPEAR THERE IS AN IMMINENT THREAT OF
CONVECTION IN THE VICINITY OF KIND...HOWEVER SHORT TERM MODELS BRING
AN INCREASED AREA OF LIFT OVER KIND OVER THE NEXT FEW HOURS. AIR
MASS IS WEAKLY UNSTABLE...SO THREAT OF CONVECTION OVER KIND WILL
CONTINUE INTO THE EVENING HOURS. PREVIOUS DISCUSSION FOLLOWS.
UPPER ENERGY WILL DROP FROM THE UPPER MIDWEST TO ILLINOIS LATE TODAY
AND INTERACT WITH A SLIGHTLY UNSTABLE ATMOSPHERE AND IS EXPECTED TO
RESULT IN ISOLATED TO SCATTERED THUNDERSTORMS ACROSS CENTRAL
INDIANA. RAPID REFRESH AND CONVECTIVE TEMPERATURES SUGGEST A 20Z
INITIATION. THE STORMS SHOULD THEN END BY 00Z. WITH COVERAGE
LOW...ONLY WENT WITH VCTS FROM 20Z-00Z. OTHERWISE...VFR CONDITIONS
AND WINDS LESS THAN 10 KNOTS THROUGH TUESDAY. DO NOT EXPECT MUCH IF
ANY FOG TONIGHT WITH DEW POINTS ONLY IN THE LOWER 50S.
HOWEVER...WOULD NOT COMPLETELY RULE OUT BRIEF MVFR OR IFR TOWARDS
DAWN.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...NIELD/RYAN
SHORT TERM...NIELD
LONG TERM....PUMA
AVIATION...MK/JAS
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
509 PM CDT MON AUG 20 2012
.UPDATE...
ISSUED AT 502 PM CDT MON AUG 20 2012
A RATHER DRY BOUNDARY LAYER CONTINUES TO PREVAIL OVER MUCH OF
SOUTHWEST KANSAS WHICH WILL PREVENT THE DEVELOPMENT AND
SUSTAINMENT OF ORGANIZED SHOWER AND THUNDERSTORM ACTIVITY ACROSS
SOUTHWEST KANSAS. AS A RESULT...HAVE SCALED BACK ON THE POP/WX
GRIDS...AND TOTAL REMOVAL OF POPS ACROSS SOUTH CENTRAL COUNTIES
WHERE PREVIOUS FORECAST HAD 30 TO 50 POPS. THE AREA THAT WILL
RECEIVE MUCH OF THE PRECIPITATION THIS EVENING AND TONIGHT WILL BE
CONFINED TO THE TEXAS PANHANDLE AND FAR WESTERN/SOUTHWESTERN
OKLAHOMA. THE DRY AIRMASS LEFT IN THE WAKE OF THE FAIRLY
IMPRESSIVE COOL, HIGH PRESSURE AREA WAS UNDER FORECAST BY SEVERAL
OF THE MODELS...AND THE GFS AND EVEN SHORT-TERM RUC13 MODEL HAVE A
TERRIBLE HANDLE ON THE LOW LEVEL MOISTURE (OR LACK THEREOF) ACROSS
SOUTHWEST KANSAS. MID AND HIGH LEVEL CLOUD COVER WILL REMAIN
THROUGH MOST OF THE NIGHT AS THE NORTHWEST FLOW DISTURBANCE MOVES
SOUTHEAST...BUT MAINLY VIRGA SHOWERS WITH AN FEW AREAS RECEIVING
SOME LIGHT RAIN SHOWERS ARE ABOUT ALL THAT THE ATMOSPHERE WILL BE
ABLE TO DISH OUT WITH THIS DRY BOUNDARY LAYER STILL IN PLACE.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 222 PM CDT MON AUG 20 2012
TONIGHT:
THE IMMEDIATE SHORT TERM FORECAST IS WHAT TO DO WITH POPS THIS EVENING.
NORTHWEST FLOW ALOFT AND OROGRAPHICALLY INDUCED CONVECTION ACROSS COLORADO WILL
CREATE A CLASSIC MCS LATE SUMMER TIME EVENT FOR FAR SW KANSAS. RIGHT
NOW THE MESOSCALE MODELS (NAM, WRF) SHOWS THAT THE BEST 310K ISENTROPIC
LIFT AND WARM AIR (THETA-E) ADVECTION WILL BE LOCATED ACROSS THE SOUTHWESTERN
COUNTIES. THIS AREA IS ALSO CLOSER TO AN APPROACHING 80 KT 250 HPA JET
STREAK MOVING ACROSS THE REGION TONIGHT. THE MOST RECENT HRRR IS QUITE
AGGRESSIVE WITH COMPOSITE REFLECTIVITIES AND ASSOCIATED PRECIPITATION
TOWARDS 05Z (MIDNIGHT) FOR THE CENTRAL COUNTIES. FOR NOW, WILL HOLD
OFF ON THIS SOLUTION SINCE THIS MODEL MIGHT BE OVERDOING THE RESULTANT
COLD POOL FROM THE CONVECTIVE SCHEME. HAVE DOUBTS FOR SEVERE WEATHER
AS DEWPOINTS ARE MAINLY IN THE 40S DEG F. THERE ARE SOME HIGHER DEWPOINTS
(LOWER 50S DEG F) ACROSS THE PANHANDLES, BUT THIS BETTER MOISTURE SHOULD
STAY SOUTH OF THE REGION. KINEMATIC PROFILES SUGGEST THE POSSIBILITY
OF SEVERE WEATHER WITH 0-6 KM BULK SHEAR FORECAST TO BE ABOUT 45 KT
AND ANVIL LEVEL STORM RELATIVE WINDS AROUND 80 KT. THE FLY IN THE OINTMENT
FOR THIS EVENING IS MEAGER CAPE ASSOCIATED WITH MARGINAL BOUNDARY
LAYER DEWPOINTS. 700-500 HPA LAPSE RATES AROUND 7.5 C/KM AND 500-300
HPA LAPSE RATES AROUND 6.7 C/KM IN COMBINATION WITH 500 J/KG OF
SBCAPE SUGGEST MARGINAL HAIL FOR ANY SUSTAINED UPDRAFT - MAINLY
TOWARDS ELKHART.
TOMORROW:
KEPT THE IDEA OF LOWER TEMPERATURES ACROSS THE SW COUNTIES AS TEMPERATURES
SHOULD BE MODERATED BY THE ANTICIPATED RAINFALL ACROSS THE REGION. I
HAVE LOWER 80S DEG F FOR THE SOUTHWEST COUNTIES AND MID TO UPPER 80S
DEG F ELSEWHERE. THINK THE 12Z NAM IS OVERDOING TEMPS ACROSS THIS REGION.
MAX CLIMO FOR THE REGION IS AROUND 88 DEG F FOR TOMORROW. THE 12Z NAM
IS SUGGESTING THE POSSIBILITY FOR CONVECTION ACROSS FAR WESTERN KANSAS
ALONG THE LEE SURFACE TROUGH FOR TOMORROW EVENING. WILL PUT SLIGHT POPS
IN THE GRIDS FOR NOW. NOT TOTALLY CONFIDENT AS UPPER LEVEL DYNAMICS
ARE FORECAST TO BE ON THE WEAKER SIDE TOMORROW.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 246 PM CDT MON AUG 20 2012
FOR TUESDAY NIGHT INTO WEDNESDAY MORNING, WILL PHASE OUT 20 PERCENT
SLIGHT CHANCES OF SHOWERS AND THUNDERSTORMS FROM OUR WESTERN
FORECAST POINTS NEAR SYRACUSE AND ELKHART BY 06Z. THE TROUGH THE
AFTERNOON CONVECTION WILL TRIGGER ON LATE TUESDAY WILL SLOWLY
DISSIPATED DURING THE EARLY OVERNIGHT PERIOD TUESDAY NIGHT.
ANOTHER SHORT WAVE WILL COME THROUGH THE NORTHWEST FLOW ALOFT LATE
WEDNESDAY AND GENERATE ANOTHER LOW PRESSURE TROUGH NEAR OUR WESTERN
BORDER. LOW 20 POPS FOR ELEVATED THUNDERSTORMS WILL RESULT AFTER
21Z WEDNESDAY, AND SPREAD EASTWARD DURING THE EVENING WEDNESDAY.
THE SURROUND OFFICES SEEMED TO FAVOR 30 PERCENT CHANCE POPS WED, SO
I STUCK WITH 30 POPS FOR ALL AREAS EXCEPT 40 PERCENT POPS IN IN OUR
EASTERN 2 TIERS OF COUNTIES, EAST OF A LINE FROM LARNED TO COLDWATER
WED NIGHT. MOST OF THESE THUNDERSTORMS WILL LIKELY BE ELEVATED AND
ONLY PRODUCE RAINFALL IN THE 0.10 RANGE IN OUR SOUTHEAST ZONES, BUT
SOMEWHAT LOWER AND ONLY IN THE 0.02 TO 0.06-INCH RANGE UP NORTH AND
TO THE WEST. THOSE UPPER WAVES ARE JUST STACKED ONE AFTER ANOTHER,
SO PRECIP CHANCES IN THE 20 TO 30 PERCENT RANGE WILL CONTINUE INTO
THURSDAY, BUT INCREASE IN THE 40 PERCENT RANGE ACROSS OUR EASTERN
1/3RD OF THE CWA, BASICALLY EAST OF A WAKEENEY TO KINSLEY TO MEADE
LINE. A STEADY SOUTHERLY FLOW WILL BRING MID 60S DEW POINTS INTO
THAT AREA THURSDAY AFTERNOON, AND A SYNOPTIC SCALE UPPER WAVE WILL
CROSS JUST NORTH OF OUR CWA THURSDAY NIGHT.
FRIDAY SHOULD SEE A LITTLE RELAXING/WEAKENING OF THE STRENGTH OF
THE PASSING UPPER WAVE, WITH ONLY OUR SOUTHEAST ZONES NEAR MEDICINE
LODGE CARRYING 30 POPS. AS A WARM FRONT NUDGES NORTH FRIDAY NIGHT
AND STEADY UPPER SCALE LIFT STAYS OVER WESTERN KANSAS, MUCH OF THE
CWA COULD SEE HIGH BASED SHOWERS AND ISOLATED STORMS FRIDAY NIGHT.
A CHANCE CATEGORY 30 PERCENT POPS WILL COVER MUCH OF THE EASTERN
HALF OF THE FORECAST AREA, WHILE 20 POPS WILL BE OVER THE SOUTHWEST
ZONES FRI NT. SATURDAY, SATURDAY NIGHT AND SUNDAY ALL LOOK GOOD FOR
30 TO 40 PERCENT RAIN CHANCES IN OUR EASTERN HALF OF THE CWA, WITH
EVEN OUR SOUTHWEST COUNTIES HAVING A 20 PERCENT CHANCE SATURDAY
NIGHT. SUNDAY WAS SOMEWHAT QUESTIONABLE AS TO WHERE THE UPPER WAVE
WILL BE, BUT OUR EASTERN-MOST ZONES FROM HAYS TO PRATT TO MEDICINE
LODGE WILL STILL HAVE 20 POPS. BY SUNDAY, THE LAST IN A SERIES OF
UPPER WAVES COULD BE FAR ENOUGH EAST TO LEAVE POPS OUT OF OUR EAST
ZONES ALL TOGETHER SUNDAY. WILL HAVE TO SEE THE NEXT MODEL RUN TO
DETERMINE IF PRECIP CHANCES ARE WARRANTED SUNDAY.
AS FOR TEMPERATURES, I ACCEPTED WHAT THE CREXTENDFCST_INIT PROCEDURE
GAVE ME. BASICALLY, FOR WEDNESDAY THROUGH SUNDAY, HIGH TEMPERATURES
WILL BE IN THE MID TO UPPER 80S ACROSS OUR NORTHERN HALF OF THE CWA,
AND FROM THE UPPER 80S TO LOWER 90S IN OUR SOUTHERN HALF. MINIMUM
TEMPERATURES WILL START OUT IN THE LOWER 60S WEDNESDAY, AND WARM TO
THE MID 60S TO LOWER 70S (SE) FRIDAY THROUGH SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1200 PM CDT MON AUG 20 2012
VFR CIGS EXPECTED THROUGH TAF PERIOD. CONVECTION LOOKS TO REMAIN SW
OF THE TERMINALS THIS EVENING IN ASSOCIATION WITH 700 HPA BAROCLINIC
BOUNDARY/ENHANCED 310K ISENTROPIC LIFT/CLOSER TO 250 HPA 80 KT JET STREAK.
SOUTHERLY WINDS WILL REMAIN IN THE 10 KT RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 60 85 61 86 / 10 10 10 20
GCK 59 84 61 88 / 20 10 20 20
EHA 60 81 62 88 / 40 20 20 20
LBL 61 82 62 88 / 30 10 20 20
HYS 58 89 61 90 / 0 10 10 20
P28 61 89 62 89 / 10 10 10 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...UMSCHEID
SYNOPSIS...SUGDEN
SHORT TERM...SUGDEN
LONG TERM...BURKE
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
249 PM CDT MON AUG 20 2012
...UPDATED FOR THE LONG TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 911 AM CDT MON AUG 20 2012
THE 20.12Z 250 HPA SYNOPTIC MAP SHOWED FAIRLY STRONG FLOW ACROSS THE
MAJORITY OF THE CONUS WITH A GOOD PORTION OF THE COUNTRY REPORTING WINDS
GREATER THAN 50 KT. A 90 KT JET WAS MOVING ASHORE ACROSS THE PACIFIC
NORTHWEST. IN OTHER AREAS, 60-70 KT NORTHWESTERLY FLOW WAS OVER THE
PLAINS (GOOD FOR MCS DEVELOPMENT THIS TIME OF YEAR) AND A STRONG 110
KT SOUTHWESTERLY JET WAS OBSERVED ACROSS THE EASTERN SEABOARD. AT 500
HPA, THE GEOPOTENTIAL HEIGHT PATTERN WAS QUITE AMPLIFIED ACROSS THE
CONUS. A RIDGE WAS LOCATED ACROSS THE DESERT SOUTHWEST. A TROF AXIS
WAS LOCATED FROM HUDSON BAY SOUTHWEST TO THE WESTERN GULF OF MEXICO.
A MINOR SHORTWAVE TROF WAS MOVING ACROSS THE NORTHERN PERIPHERY OF THE
MID LEVEL RIDGE ACROSS IDAHO AND UTAH. SOME MID LEVEL MOISTURE WAS NOTED
ACROSS THE SPINE OF THE ROCKIES. AT 700 HPA, A EXPANSIVE AREA OF COLD
TEMPERATURES WITH VALUES IN THE 0 TO -3 DEG C RANGE EXTENDED ACROSS
THE MISSISSIPPI RIVER VALLEY AND POINTS EAST. AT 850 HPA, THE COLD POOL
ASSOCIATED WITH THE AFOREMENTIONED TROF WAS FARTHER EAST WITH VALUES
IN THE 7 TO 12 DEG C RANGE ACROSS THE OHIO RIVER VALLEY AND POINTS EAST.
ACROSS KANSAS, TEMPERATURES WERE WARMER (18 DEG C) ASSOCIATED WITH LOW
LEVEL RIDGING/WARM AIR ADVECTION. AT THE SURFACE, LOW LEVEL MOISTURE
(DEWPOINTS > 70 DEG F) WERE SOUTH OF A BOUNDARY LOCATED ACROSS TEXAS.
A RIDGE OF HIGH PRESSURE EXTENDED ACROSS THE MIDWEST/EASTERN PORTION
OF THE GREAT PLAINS. A WEAK STATIONARY BOUNDARY EXISTED ACROSS COLORADO
AND WYOMING.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 222 PM CDT MON AUG 20 2012
TONIGHT:
THE IMMEDIATE SHORT TERM FORECAST IS WHAT TO DO WITH POPS THIS EVENING.
NORTHWEST FLOW ALOFT AND OROGRAPHICALLY INDUCED CONVECTION ACROSS COLORADO WILL
CREATE A CLASSIC MCS LATE SUMMER TIME EVENT FOR FAR SW KANSAS. RIGHT
NOW THE MESOSCALE MODELS (NAM, WRF) SHOWS THAT THE BEST 310K ISENTROPIC
LIFT AND WARM AIR (THETA-E) ADVECTION WILL BE LOCATED ACROSS THE SOUTHWESTERN
COUNTIES. THIS AREA IS ALSO CLOSER TO AN APPROACHING 80 KT 250 HPA JET
STREAK MOVING ACROSS THE REGION TONIGHT. THE MOST RECENT HRRR IS QUITE
AGGRESSIVE WITH COMPOSITE REFLECTIVITIES AND ASSOCIATED PRECIPITATION
TOWARDS 05Z (MIDNIGHT) FOR THE CENTRAL COUNTIES. FOR NOW, WILL HOLD
OFF ON THIS SOLUTION SINCE THIS MODEL MIGHT BE OVERDOING THE RESULTANT
COLD POOL FROM THE CONVECTIVE SCHEME. HAVE DOUBTS FOR SEVERE WEATHER
AS DEWPOINTS ARE MAINLY IN THE 40S DEG F. THERE ARE SOME HIGHER DEWPOINTS
(LOWER 50S DEG F) ACROSS THE PANHANDLES, BUT THIS BETTER MOISTURE SHOULD
STAY SOUTH OF THE REGION. KINEMATIC PROFILES SUGGEST THE POSSIBILITY
OF SEVERE WEATHER WITH 0-6 KM BULK SHEAR FORECAST TO BE ABOUT 45 KT
AND ANVIL LEVEL STORM RELATIVE WINDS AROUND 80 KT. THE FLY IN THE OINTMENT
FOR THIS EVENING IS MEAGER CAPE ASSOCIATED WITH MARGINAL BOUNDARY
LAYER DEWPOINTS. 700-500 HPA LAPSE RATES AROUND 7.5 C/KM AND 500-300
HPA LAPSE RATES AROUND 6.7 C/KM IN COMBINATION WITH 500 J/KG OF
SBCAPE SUGGEST MARGINAL HAIL FOR ANY SUSTAINED UPDRAFT - MAINLY
TOWARDS ELKHART.
TOMORROW:
KEPT THE IDEA OF LOWER TEMPERATURES ACROSS THE SW COUNTIES AS TEMPERATURES
SHOULD BE MODERATED BY THE ANTICIPATED RAINFALL ACROSS THE REGION. I
HAVE LOWER 80S DEG F FOR THE SOUTHWEST COUNTIES AND MID TO UPPER 80S
DEG F ELSEWHERE. THINK THE 12Z NAM IS OVERDOING TEMPS ACROSS THIS REGION.
MAX CLIMO FOR THE REGION IS AROUND 88 DEG F FOR TOMORROW. THE 12Z NAM
IS SUGGESTING THE POSSIBILITY FOR CONVECTION ACROSS FAR WESTERN KANSAS
ALONG THE LEE SURFACE TROUGH FOR TOMORROW EVENING. WILL PUT SLIGHT POPS
IN THE GRIDS FOR NOW. NOT TOTALLY CONFIDENT AS UPPER LEVEL DYNAMICS
ARE FORECAST TO BE ON THE WEAKER SIDE TOMORROW.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 246 PM CDT MON AUG 20 2012
FOR TUESDAY NIGHT INTO WEDNESDAY MORNING, WILL PHASE OUT 20 PERCENT
SLIGHT CHANCES OF SHOWERS AND THUNDERSTORMS FROM OUR WESTERN
FORECAST POINTS NEAR SYRACUSE AND ELKHART BY 06Z. THE TROUGH THE
AFTERNOON CONVECTION WILL TRIGGER ON LATE TUESDAY WILL SLOWLY
DISSIPATED DURING THE EARLY OVERNIGHT PERIOD TUESDAY NIGHT.
ANOTHER SHORT WAVE WILL COME THROUGH THE NORTHWEST FLOW ALOFT LATE
WEDNESDAY AND GENERATE ANOTHER LOW PRESSURE TROUGH NEAR OUR WESTERN
BORDER. LOW 20 POPS FOR ELEVATED THUNDERSTORMS WILL RESULT AFTER
21Z WEDNESDAY, AND SPREAD EASTWARD DURING THE EVENING WEDNESDAY.
THE SURROUND OFFICES SEEMED TO FAVOR 30 PERCENT CHANCE POPS WED, SO
I STUCK WITH 30 POPS FOR ALL AREAS EXCEPT 40 PERCENT POPS IN IN OUR
EASTERN 2 TIERS OF COUNTIES, EAST OF A LINE FROM LARNED TO COLDWATER
WED NIGHT. MOST OF THESE THUNDERSTORMS WILL LIKELY BE ELEVATED AND
ONLY PRODUCE RAINFALL IN THE 0.10 RANGE IN OUR SOUTHEAST ZONES, BUT
SOMEWHAT LOWER AND ONLY IN THE 0.02 TO 0.06-INCH RANGE UP NORTH AND
TO THE WEST. THOSE UPPER WAVES ARE JUST STACKED ONE AFTER ANOTHER,
SO PRECIP CHANCES IN THE 20 TO 30 PERCENT RANGE WILL CONTINUE INTO
THURSDAY, BUT INCREASE IN THE 40 PERCENT RANGE ACROSS OUR EASTERN
1/3RD OF THE CWA, BASICALLY EAST OF A WAKEENEY TO KINSLEY TO MEADE
LINE. A STEADY SOUTHERLY FLOW WILL BRING MID 60S DEW POINTS INTO
THAT AREA THURSDAY AFTERNOON, AND A SYNOPTIC SCALE UPPER WAVE WILL
CROSS JUST NORTH OF OUR CWA THURSDAY NIGHT.
FRIDAY SHOULD SEE A LITTLE RELAXING/WEAKENING OF THE STRENGTH OF
THE PASSING UPPER WAVE, WITH ONLY OUR SOUTHEAST ZONES NEAR MEDICINE
LODGE CARRYING 30 POPS. AS A WARM FRONT NUDGES NORTH FRIDAY NIGHT
AND STEADY UPPER SCALE LIFT STAYS OVER WESTERN KANSAS, MUCH OF THE
CWA COULD SEE HIGH BASED SHOWERS AND ISOLATED STORMS FRIDAY NIGHT.
A CHANCE CATEGORY 30 PERCENT POPS WILL COVER MUCH OF THE EASTERN
HALF OF THE FORECAST AREA, WHILE 20 POPS WILL BE OVER THE SOUTHWEST
ZONES FRI NT. SATURDAY, SATURDAY NIGHT AND SUNDAY ALL LOOK GOOD FOR
30 TO 40 PERCENT RAIN CHANCES IN OUR EASTERN HALF OF THE CWA, WITH
EVEN OUR SOUTHWEST COUNTIES HAVING A 20 PERCENT CHANCE SATURDAY
NIGHT. SUNDAY WAS SOMEWHAT QUESTIONABLE AS TO WHERE THE UPPER WAVE
WILL BE, BUT OUR EASTERN-MOST ZONES FROM HAYS TO PRATT TO MEDICINE
LODGE WILL STILL HAVE 20 POPS. BY SUNDAY, THE LAST IN A SERIES OF
UPPER WAVES COULD BE FAR ENOUGH EAST TO LEAVE POPS OUT OF OUR EAST
ZONES ALL TOGETHER SUNDAY. WILL HAVE TO SEE THE NEXT MODEL RUN TO
DETERMINE IF PRECIP CHANCES ARE WARRANTED SUNDAY.
AS FOR TEMPERATURES, I ACCEPTED WHAT THE CREXTENDFCST_INIT PROCEDURE
GAVE ME. BASICALLY, FOR WEDNESDAY THROUGH SUNDAY, HIGH TEMPERATURES
WILL BE IN THE MID TO UPPER 80S ACROSS OUR NORTHERN HALF OF THE CWA,
AND FROM THE UPPER 80S TO LOWER 90S IN OUR SOUTHERN HALF. MINIMUM
TEMPERATURES WILL START OUT IN THE LOWER 60S WEDNESDAY, AND WARM TO
THE MID 60S TO LOWER 70S (SE) FRIDAY THROUGH SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1200 PM CDT MON AUG 20 2012
VFR CIGS EXPECTED THROUGH TAF PERIOD. CONVECTION LOOKS TO REMAIN SW
OF THE TERMINALS THIS EVENING IN ASSOCIATION WITH 700 HPA BAROCLINIC
BOUNDARY/ENHANCED 310K ISENTROPIC LIFT/CLOSER TO 250 HPA 80 KT JET STREAK.
SOUTHERLY WINDS WILL REMAIN IN THE 10 KT RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 60 85 60 86 / 10 10 10 0
GCK 59 84 60 88 / 30 10 20 0
EHA 60 81 61 87 / 60 20 20 10
LBL 61 82 61 88 / 60 10 20 0
HYS 58 89 60 90 / 0 10 10 0
P28 61 89 61 89 / 50 10 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...SUGDEN
LONG TERM...BURKE
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
222 PM CDT MON AUG 20 2012
...UPDATE TO SHORT TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 911 AM CDT MON AUG 20 2012
THE 20.12Z 250 HPA SYNOPTIC MAP SHOWED FAIRLY STRONG FLOW ACROSS THE
MAJORITY OF THE CONUS WITH A GOOD PORTION OF THE COUNTRY REPORTING WINDS
GREATER THAN 50 KT. A 90 KT JET WAS MOVING ASHORE ACROSS THE PACIFIC
NORTHWEST. IN OTHER AREAS, 60-70 KT NORTHWESTERLY FLOW WAS OVER THE
PLAINS (GOOD FOR MCS DEVELOPMENT THIS TIME OF YEAR) AND A STRONG 110
KT SOUTHWESTERLY JET WAS OBSERVED ACROSS THE EASTERN SEABOARD. AT 500
HPA, THE GEOPOTENTIAL HEIGHT PATTERN WAS QUITE AMPLIFIED ACROSS THE
CONUS. A RIDGE WAS LOCATED ACROSS THE DESERT SOUTHWEST. A TROF AXIS
WAS LOCATED FROM HUDSON BAY SOUTHWEST TO THE WESTERN GULF OF MEXICO.
A MINOR SHORTWAVE TROF WAS MOVING ACROSS THE NORTHERN PERIPHERY OF THE
MID LEVEL RIDGE ACROSS IDAHO AND UTAH. SOME MID LEVEL MOISTURE WAS NOTED
ACROSS THE SPINE OF THE ROCKIES. AT 700 HPA, A EXPANSIVE AREA OF COLD
TEMPERATURES WITH VALUES IN THE 0 TO -3 DEG C RANGE EXTENDED ACROSS
THE MISSISSIPPI RIVER VALLEY AND POINTS EAST. AT 850 HPA, THE COLD POOL
ASSOCIATED WITH THE AFOREMENTIONED TROF WAS FARTHER EAST WITH VALUES
IN THE 7 TO 12 DEG C RANGE ACROSS THE OHIO RIVER VALLEY AND POINTS EAST.
ACROSS KANSAS, TEMPERATURES WERE WARMER (18 DEG C) ASSOCIATED WITH LOW
LEVEL RIDGING/WARM AIR ADVECTION. AT THE SURFACE, LOW LEVEL MOISTURE
(DEWPOINTS > 70 DEG F) WERE SOUTH OF A BOUNDARY LOCATED ACROSS TEXAS.
A RIDGE OF HIGH PRESSURE EXTENDED ACROSS THE MIDWEST/EASTERN PORTION
OF THE GREAT PLAINS. A WEAK STATIONARY BOUNDARY EXISTED ACROSS COLORADO
AND WYOMING.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 222 PM CDT MON AUG 20 2012
TONIGHT:
THE IMMEDIATE SHORT TERM FORECAST IS WHAT TO DO WITH POPS THIS EVENING.
NORTHWEST FLOW ALOFT AND OROGRAPHICALLY INDUCED CONVECTION ACROSS COLORADO WILL
CREATE A CLASSIC MCS LATE SUMMER TIME EVENT FOR FAR SW KANSAS. RIGHT
NOW THE MESOSCALE MODELS (NAM, WRF) SHOWS THAT THE BEST 310K ISENTROPIC
LIFT AND WARM AIR (THETA-E) ADVECTION WILL BE LOCATED ACROSS THE SOUTHWESTERN
COUNTIES. THIS AREA IS ALSO CLOSER TO AN APPROACHING 80 KT 250 HPA JET
STREAK MOVING ACROSS THE REGION TONIGHT. THE MOST RECENT HRRR IS QUITE
AGGRESSIVE WITH COMPOSITE REFLECTIVITIES AND ASSOCIATED PRECIPITATION
TOWARDS 05Z (MIDNIGHT) FOR THE CENTRAL COUNTIES. FOR NOW, WILL HOLD
OFF ON THIS SOLUTION SINCE THIS MODEL MIGHT BE OVERDOING THE RESULTANT
COLD POOL FROM THE CONVECTIVE SCHEME. HAVE DOUBTS FOR SEVERE WEATHER
AS DEWPOINTS ARE MAINLY IN THE 40S DEG F. THERE ARE SOME HIGHER DEWPOINTS
(LOWER 50S DEG F) ACROSS THE PANHANDLES, BUT THIS BETTER MOISTURE SHOULD
STAY SOUTH OF THE REGION. KINEMATIC PROFILES SUGGEST THE POSSIBILITY
OF SEVERE WEATHER WITH 0-6 KM BULK SHEAR FORECAST TO BE ABOUT 45 KT
AND ANVIL LEVEL STORM RELATIVE WINDS AROUND 80 KT. THE FLY IN THE OINTMENT
FOR THIS EVENING IS MEAGER CAPE ASSOCIATED WITH MARGINAL BOUNDARY LAYER
DEWPOINTS. 700-500 HPA LAPSE RATES AROUND 7.5C/KM AND 500-300 HPA LAPSE
RATES AROUND 6.7 K/CM IN COMBINATION WITH 500 J/KG OF SBCAPE SUGGEST
MARGINAL HAIL FOR ANY SUSTAINED UPDRAFT - MAINLY TOWARDS ELKHART.
TOMORROW:
KEPT THE IDEA OF LOWER TEMPERATURES ACROSS THE SW COUNTIES AS TEMPERATURES
SHOULD BE MODERATED BY THE ANTICIPATED RAINFALL ACROSS THE REGION. I
HAVE LOWER 80S DEG F FOR THE SOUTHWEST COUNTIES AND MID TO UPPER 80S
DEG F ELSEWHERE. THINK THE 12Z NAM IS OVERDOING TEMPS ACROSS THIS REGION.
MAX CLIMO FOR THE REGION IS AROUND 88 DEG F FOR TOMORROW. THE 12Z NAM
IS SUGGESTING THE POSSIBILITY FOR CONVECTION ACROSS FAR WESTERN KANSAS
ALONG THE LEE SURFACE TROUGH FOR TOMORROW EVENING. WILL PUT SLIGHT POPS
IN THE GRIDS FOR NOW. NOT TOTALLY CONFIDENT AS UPPER LEVEL DYNAMICS
ARE FORECAST TO BE ON THE WEAKER SIDE TOMORROW.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 548 AM CDT MON AUG 20 2012
LINGERING EARLY MORNING CONVECTION ACROSS SOUTHWEST KANSAS SHOULD
MOVE INTO OKLAHOMA BY MID DAY TUESDAY BASED ON TIMING OF THE UPPER
LEVEL SHORTWAVE TROUGH AND 300-250MB JET STREAK. BY TUESDAY EVENING
ANTICYCLONIC FLOW IS FORECAST TO BEGIN TO SPREAD EAST ACROSS THE
CENTRAL HIGH PLAINS. STILL WITH WEAKER LARGE SCALE LIFT PRESENT THE
NAM, GFS, AND ECMWF DOES HAVE SOME MOISTURE AND WARM AIR ADVECTION
DEVELOPING ACROSS PORTIONS OF SOUTHWEST KANSAS LATE IN THE DAY.
MOISTURE PROFILES IN THE 850-700MB LEVEL BASED ON VARIOUS 00Z MODEL
SOUNDINGS DOES APPEAR SOMEWHAT LACKING, HOWEVER GIVEN THE
INSTABILITY FORECAST BY THESE MODEL SOUNDINGS AND WEAK INHIBITION
AM NOT COMPLETELY ABLE TO RULE OUT AN ISOLATED STORM OR TWO LATE
TUESDAY. MODEL SOUNDINGS ALSO INDICATING GOOD MIXING POTENTIAL
POSSIBLE TUESDAY AFTERNOON SO WILL USE THE 800MB TEMPERATURE TRENDS
AS A GUIDE FOR HIGHS. BY USING A MEAN 800MB TEMPERATURES AT 00Z
WEDNESDAY WHICH VARIES FROM 13C TO 16C AND TAKING INTO ACCOUNT THE
EXPECTED RAINFALL IT STILL APPEARS THAT THE PREVIOUS FORECAST HAD
THE RIGHT IDEA WITH THE WARM HIGHS BEING IN NORTH CENTRAL KANSAS AND
THE COOLEST BEING IN EXTREME SOUTHWEST KANSAS AROUND ELKHART.
BY EARLY WEDNESDAY A WESTERLY DOWNSLOPE FLOW WILL BEGIN TO DEVELOP
AND 700MB TEMPERATURES ARE FORECAST TO WARM FROM AROUND 8C IN
WESTERN KANSAS TO NEAR 12C. A TROUGH OF LOW PRESSURE AT THE SURFACE
ACROSS EASTERN COLORADO IS ALSO FORECAST TO DEEPEN AS AN UPPER LEVEL
DISTURBANCE MOVES EAST ACROSS THE CENTRAL ROCKIES. AS THIS NEXT
SYSTEM EXITS TO ROCKIES AND MOVES OUT INTO THE PLAINS ANOTHER ROUND
OF THUNDERSTORMS WILL BE POSSIBLE AS MOISTURE RETURNS AND 850MB WARM
AIR ADVECTION DEVELOPS WEDNESDAY NIGHT JUST EAST OF THE WARMER 700MB
TEMPERATURES. THE GENERAL TREND OF THIS PRECIPITATION SPREADING EAST
ACROSS WESTERN KANSAS OVERNIGHT INTO EARLY THURSDAY STILL APPEARS ON
TRACK SO NO MAJOR ADJUSTMENTS PLANNED.
BY LATE WEEK THE UPPER LEVEL RIDGE AXIS LOCATED ACROSS THE ROCKIES
MID WEEK IS FORECAST TO WEAKEN AND MOVE EAST INTO THE CENTRAL PLAINS
AS AN UPPER LOW/TROUGH MOVES ACROSS THE SOUTHWEST UNTIED STATES.
EACH MODEL SUGGESTS SUBTLE UPPER WAVES WILL MOVE ACROSS THE CENTRAL
PLAINS AS THIS UPPER RIDGE AXIS SLIDES EAST AND WEAKENS THURSDAY AND
FRIDAY WITH SCATTERED THUNDERSTORMS POSSIBLE WITH EACH OF THESE
SYSTEMS. AT THIS TIME CONFIDENCE IS NOT HIGH ON ANY OF THE WEAKER
FEATURES LATE WEEK SO HAVE DECIDED TO STAY CLOSE TO THE
CREXTENDFCST_INIT. A WARMING TREND LATE WEEK IS EXPECTED ALSO GIVEN
THE 850-700MB TEMPERATURE TRENDS FROM THE ECMWF AND GFS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1200 PM CDT MON AUG 20 2012
VFR CIGS EXPECTED THROUGH TAF PERIOD. CONVECTION LOOKS TO REMAIN SW
OF THE TERMINALS THIS EVENING IN ASSOCIATION WITH 700 HPA BAROCLINIC
BOUNDARY/ENHANCED 310K ISENTROPIC LIFT/CLOSER TO 250 HPA 80 KT JET STREAK.
SOUTHERLY WINDS WILL REMAIN IN THE 10 KT RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 60 85 60 86 / 10 10 10 0
GCK 59 84 60 88 / 30 10 20 0
EHA 60 81 61 87 / 60 20 20 10
LBL 61 82 61 88 / 60 10 20 0
HYS 58 89 60 90 / 0 10 10 0
P28 61 89 61 89 / 50 10 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...SUGDEN
LONG TERM...BURGERT
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1254 PM EDT MON AUG 20 2012
.SYNOPSIS...
WEAK HIGH PRESSURE WILL REMAIN OVER THE REGION TODAY. A WEAK COLD
FRONT WILL APPROACH FROM THE NORTHWEST TONIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
1250 PM UPDATE...AGAIN MADE CHANGES TO POPS AND SKY FOR THIS
UPDATE. SATELLITE IMAGERY SHOWS CUMULUS HAVE DEVELOPED OVER MUCH OF
THE FORECAST AREA, SO INCREASED MOST AREAS TO PARTLY SUNNY FOR THE
REMAINDER OF THE AFTERNOON. THE HRRR MODEL CONTINUES TO INDICATE
THAT SHOWERS WILL POP UP OVER NORTHWEST MAINE THIS AFTERNOON, BUT
IT HAS INCREASED COVERAGE FROM EARLIER RUNS. HAVE FOLLOWED SUIT
AND NOW HAVE SCATTERED SHOWERS ACROSS NW AROOSTOOK AND SOMERSET
COUNTIES. ALSO MADE ADJUSTMENTS TO HIGH TEMPS TO MATCH CURRENT
TRENDS. NO OTHER CHANGES WERE NEEDED.
PREVIOUS DISCUSSION...WEAK HIGH PRESSURE WILL REMAIN OVER THE
STATE TODAY. A WEAK COLD FRONT WILL APPROACH FROM THE NORTHWEST
TONIGHT. DO NOT EXPECT PRECIPITATION OR QPF THIS PERIOD WITH THE
COLD FRONT STALLING IN SOUTHWEST FLOW ALOFT BEFORE REACHING THE
NORTHERN PORTION OF THE FORECAST AREA. FOR WIND WILL BLEND THE
NAM12 AND GMOS. FOR TEMPERATURE AND DEW POINT HAVE USED THE GMOS
AND WILL ADJUST MAXIMUM TEMPERATURE HIGHER TODAY AND LOWER THAN
GUIDANCE TONIGHT.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
BIGGEST CHALLENGE THIS TERM WILL BE PRECIP CHANCES AND
TEMPERATURES AS A SERIES OF WEAK FRONTS AFFECT THE CWA.
THE FIRST FRONT IS SHOWN BY THE SHORT RANGE MODELS INCLUDING THE
CANADIAN GEM TO MOVE ACROSS THE REGION ON TUESDAY. THE ASSOCIATED
SOUNDINGS INDICATE THAT MOISTURE WILL BE LIMITED AND CONFINED TO
THE MID AND UPPER LEVELS. SOME MID LEVEL FORCING IS THERE W/WEAK
LLVL CONVERGENCE TO PROVIDE LIFT. ATTM, THINKING HERE IS THAT
SHOWER ACTIVITY WILL BE WIDELY SCATTERED AND CONFINED ACROSS THE
NORTHERN 1/2 OF THE CWA. COLLABORATED W/GYX ON PULLING POPS BACK
TO 20-30% AND LEFT OUT THE MENTION OF THUNDER DUE TO LIMITED
INSTABILITY. SB/MUCAPES NOT MORE THAN 200 JOULES AND LIS STAY AOA 0.
BACKED AWAY FROM HPC`S QPF AS IT LOOKS TO HIGH GIVEN THE PATTERN
THE CWA IS IN. EXPECTING NOTHING MORE THAN A FEW HUNDREDTHS IN THE
MOVRE CONCENTRATED ACTIVITY. TEMPERATURES ARE EXPECTED TO BE IN
THE MID/UPPER 70S.
SKIES WILL BECOME PARTLY CLOUDY TUESDAY NIGHT W/SOME HIGH LEVEL
CLOUDINESS SHOWN BY THE MODEL SOUNDINGS ESPECIALLY THE GFS MAINLY
ACROSS NORTHERN AND WESTERN MAINE. UPPER AIR DATA INDICATED SOME
COOLER TEMPERATURES COMING IN W/READINGS ACROSS THE NORTHERN AND
WEST HITTING THE UPPER 40S ESPECIALLY IN THE LOW LYING AREAS.
ELSEWHERE, OVERNIGHT TEMPERATURES IN THE 50S IS EXPECTED. A DRY
DAY FOR WEDNESDAY W/SOME CUMULUS DEVELOPMENT. THE GFS SOUNDINGS
INDICATE AN UNSTABLE ENVIRONMENT W/SB CAPES HITTING 200-400 JOULES
AND LIS DROPPING DOWN TO -1 TO -2. AS HAS BEEN THE CASE, MOISTURE
IS LIMITED AND FORCING IS WEAK W/THESE FRONTS AND THEREFORE KEPT
THE MENTION OF SHOWERS/STORMS OUT OF THE FCST. STAYED CLOSE TO THE
DAYCREW`S TEMPERATURES W/UPPER 70S TO AROUND 80.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
IT LOOKS A CONTINUATION OF DRY WEATHER FOR THE MOST PART RIGHT INTO
THE WEEKEND. FOR THIS FCST CYCLE, A BLEND OF THE GMOS AND ECMWF
WAS USED WHICH SHOWS A CHANCE FOR SOME LIGHT PRECIP LATER THURSDAY
AS FRONTAL BOUNDARY APCHS FROM THE WEST. THE ECMWF AND GFS BOTH
SHOW SOME FORCING IN THE MID LEVELS W/INCREASING MOISTURE FROM
850-7000MBS TO SUPPORT SOME SHOWER ACTIVITY. THEREFORE, CARRIED 20-30%
POPS ACROSS THE NORTH AND WEST FOR THURSDAY AFTERNOON AND EVENING
AS THE FRONT LOOKS LIKE IT ALIGNS W/THE UPPER FLOW TO KEEP IT FROM
CLEARING THE COAST BY FRIDAY MORNING. THE GFS AND ECMWF POINT TO
SOME MEASURABLE QPF ACROSS THE SOUTHERN PORTION OF THE CWA INTO
THE COAST BY FRIDAY AFTERNOON. FORCING IS WEAK AND MOISTURE
APPEARS LIMITED AS SUPPORTED BY THE CANADIAN GLOBAL. THE GFS AND
ECMWF COULD BE SUFFERING FROM CONVECTIVE FEEDBACK W/THE BULLSEYE
OF QPF ACROSS THE DOWNEAST AND COAST. ATTM, KEPT THE MENTION OF
SHOWERS OUT OF THE FCST.
THE UPPER LEVEL PATTERN APPEARS TO BE SHOWING A SHIFT IN THE LONG
WAVE TROF PATTERN AS HIGH PRES IS FCST TO SET UP ACROSS THE
NORTHEASTERN US BY THE WEEKEND. THIS WILL MEAN DRY AND PLEASANT
CONDITIONS W/SEASONAL TEMPERATURES EXPECTED THROUGH THE PERIOD.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
NEAR TERM: VFR CONDITIONS TODAY AND TONIGHT.
SHORT TERM: VFR LOOKS TO BE THE GOING RATE THROUGH THE FCST PERIOD.
THERE IS THE POTENTIAL FOR BRIEF MVFR VSBYS FOR FOG FOR KPQI AND
KHUL DURING THE EARLY MORNINGS AS THESE AIR FIELDS SIT LOW.
&&
.MARINE...
NEAR TERM: EXPECT VERY LIGHT WINDS TODAY INTO TONIGHT. HAVE
BLENDED THE NAM12 AND GFS40 FOR WIND. FOR SEAS: VERY LIGHT WIND
CONDITIONS CURRENTLY ACROSS THE GULF OF MAINE. WAVES IN COASTAL
WATERS PRIMARILY THE RESULT OF LONG PERIOD WAVE...BASED ON
SPECTRAL DENSITY PLOT FROM 44027 AND WNA SPECTRAL FORECAST MOST OF
THIS RESULTING FROM SOUTHERLY FETCH OFF EAST COAST OF US. SPECTRAL
DENSITY PLOT ALSO SHOWING SOME LONGER PERIOD WAVE AROUND 14
SECONDS WHICH IS LIKELY A FORE-RUNNER OF WAVE GROUPS FROM TROPICAL
SYSTEMS. HAVE USED THE SWAN/NAM FOR WAVE GRIDS.
SHORT TERM: NO HEADLINES EXPECTED THROUGH THE PERIOD. BASICALLY
LIGHT WINDS W/A CONTINUED SWELL RIGHT INTO MID WEEK AT LEAST. A
SWELL IS OUT THERE ATTM W/A PERIOD OF 8-9 SECONDS. SEE NO REASON
TO DEVIATE FROM THIS AND THEREFORE CARRIED THE MENTION OF A SE
SWELL RIGHT INTO TUE NIGHT.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HASTINGS/MIGNONE
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...HASTINGS/MIGNONE
MARINE...HASTINGS/MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
243 PM EDT MON AUG 20 2012
.SYNOPSIS...
AFTER ANOTHER DAY WITH A SLIGHT CHANCE FOR THUNDERSTORMS...EXPECT
DRY WEATHER AND NEAR NORMAL TEMPERATURES FOR WEDNESDAY INTO THE
WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
TWO UPPER LEVEL SHORTWAVES...ONE CURRENTLY OVER CENTRAL OHIO AND
ANOTHER OVER WESTERN PENNSYLVANIA...WILL CONTINUE TO ROTATE EAST
AROUND UPPER LEVEL TROUGH. ONCE THESE SHORTWAVES MOVE
THROUGH...SUPPORT FOR SHOWERS AND ISOLATED THUNDERSTORMS IS EXPECTED
TO DIMINISH. HAVE GONE AHEAD AND COMPLETELY DRIED OUT POPS FOR THE
OVERNIGHT PERIOD. ALTHOUGH NOT ALL LOCATIONS HAD FOG DEVELOPMENT
THIS MORNING...HAVE GONE WITH AREAS OF FOG OVERNIGHT EVERYWHERE WITH
SOLID MODEL AGREEMENT AND NEARLY CALM WINDS EXPECTED.
UPPER LEVEL TROUGH AXIS WILL SHIFT SOUTH INTO LOWER MICHIGAN AND
INDIANA BY TUESDAY MORNING. AS THE AXIS PUSHES EAST...TROUGH WILL
BEGIN TO FILL IN AND WEAKEN. WITH WANING SUPPORT...HAVE ONLY
INCLUDED EASTERN OHIO IN CHANCE POPS TOMORROW...KEEPING ALL OTHER
LOCATIONS UNDER SLIGHT CHANCE POPS...WHICH STILL MAY BE OVERDONE.
WITH SLIGHTLY LESS CLOUD COVER...HIGH TEMPERATURES TOMORROW SHOULD
BE A COUPLE OF DEGREES WARMER THAN TODAY.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
UPPER LEVEL TROUGH WILL BE OVER THE AREA ON WEDNESDAY AND MOVING
EAST ON THURSDAY. WITH A RETURN TO ZONAL FLOW...CONDITIONS ARE
EXPECTED TO BE DRY WEDNESDAY AND THURSDAY. SOME MOISTURE MAY TRY TO
SLIDE UP ALONG THE RIDGES WEDNESDAY AFTERNOON...BUT DO NOT HAVE
ENOUGH CONFIDENCE IN THIS TO INCLUDE A CHANCE FOR SHOWERS AT THIS
TIME. WINDS WILL BE LIGHT AND VARIABLE...AND HIGH TEMPERATURES
SHOULD RETURN TO THE 80S FOR NEARLY ALL LOCATIONS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
CONSENSUS OF RECENT ECMWF AND NAEFS MODEL OUTPUT CONTINUES TO SHOW
BROAD HIGH PRESSURE UNDER WEAK FLOW ALOFT ACROSS THE EASTERN U.S.
INTO THE WEEKEND. THE MODEL OUTPUT HAS BEEN TRENDING TO SHOW A
WEAK-LOOKING UPPER LEVEL TROUGH MOVING EASTBOUND ALONG THE CANADIAN
BORDER THIS WEEKEND, THAT MAY AFFECT THE UPPER OHIO VALLEY MONDAY OR
TUESDAY.
SO AT THIS JUNCTURE, CONTINUE TO EXPECT DRY CONDITIONS ACROSS THE
UPPER OHIO VALLEY THROUGH SUNDAY IF NOT MONDAY.
DUE TO THE RELATIVE LACK OF CLOUDS THIS PERIOD, CONTINUE TO EXPECT
EACH DAY TO HAVE A LARGER THAN NORMAL DIURNAL TEMPERATURE RANGE.
SO CONCUR WITH HPC THINKING...WITH SUPPORT FROM RECENT GFS AND ECMWF
MOS AND NAEFS MEDIAN VALUES...THAT LOWS FRIDAY CAN BE UP TO 5
DEGREES COOLER THAN NORMAL...WHILE HIGHS FRIDAY WILL BE NEAR OR
SLIGHTLY WARMER THAN NORMAL.
WITH POTENTIAL OF SURFACE DEW POINTS CLIMBING TO NEAR NORMAL VALUES
THIS WEEKEND...EXPECT LOWS THIS WEEKEND AND MONDAY TO BE CLOSE TO
NORMAL...WHILE HIGHS CAN BE UP TO 5 DEGREES WARMER THAN NORMAL.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
BLEND OF RECENT RADAR, SURFACE, AND HRRR MODEL OUTPUT SHOW BANDS OF
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ACROSS NORTHEASTERN
OHIO AND NORTHWESTERN PENNSYLVANIA WILL MOVE SOUTHEASTWARD AT 15 KTS
THROUGH THE REST OF THE UPPER OHIO VALLEY THROUGH 00Z.
CONDITIONS WILL CONTINUE TO BE MAINLY VFR THROUGH 06Z, BUT A BRIEF
EPISODE OF RESTRICTIONS, MAINLY MVFR VISIBILITY, CAN OCCUR WITH
HEAVIER SHOWERS. THE SHOWER BANDS ARE ASSOCIATED WITH THE PASSAGE OF
AN UPPER LEVEL SHORT-WAVE TROUGH.
PER RECENT GFS LAMP AND NAM MOS AND CLIMATOLOGICAL CONSIDERATIONS,
HAVE ADDED A PERIOD OF IFR FOG EARLY TUESDAY MORNING, 07Z-12Z.
EVAPORATION OF RAINFALL TONIGHT MAY INDUCE A CLIMB IN SURFACE DEW
POINTS THIS EVENING, AND A LIKEWISE CLIMB IN UPS FOG TECHNIQUE CROSS
OVER VALUES, INTO THE MID AND UPPER 50S. SUCH VALUES WOULD BE
FAVORABLE FOR IFR FOG FORMATION AS THEY CAN BE UP TO 3 DEGREES
COLDER THAN CURRENTLY FORECASTED LOW TEMPERATURES.
AFTER FOG BURNS OFF TUESDAY MORNING, EXPECT NONSTOP VFR THE REST
OF DAYTIME TUESDAY.
.OUTLOOK/ TUESDAY NIGHT THROUGH SATURDAY/...
GENERALLY VFR, EXCEPT FOR RESTRICTIONS DUE TO EARLY MORNING RIVER
VALLEY FOG.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GAYLORD MI
154 PM EDT MON AUG 20 2012
.SYNOPSIS...
ISSUED AT 400 AM EDT MON AUG 20 2012
HIGH PRESSURE WILL BUILD INTO THE GREAT LAKES TODAY. AS THIS HIGH
SLIDES TO THE MID-ATLANTIC STATES WEDNESDAY AND THURSDAY...WINDS
WILL SHIFT TO THE SOUTHWEST...BRINGING WARMER TEMPERATURES TO THE
REGION. A WEAK COOL FRONT WILL TRY TO EASE IN THURSDAY AND
FRIDAY...WHICH MAY TRIGGER A SHOWER OR THUNDERSTORM LATE NEXT
WEEK...INTO NEXT WEEKEND. HOWEVER...THE WEATHER WILL BE DRY AND FAIR
MOST OF THE TIME.
&&
.UPDATE...
ISSUED AT 154 PM EDT MON AUG 20 2012
LOTS OF SHWRS ON RADAR...WITH BRIEF CORES PULSING TO 55 DBZ BEFORE
COLLAPSING IN WEAK 0-6KM SHEAR AROUND 5 KTS. SHWRS ARE MOST
NUMEROUS OVER THE ERN U.P. AND MORE SCT OVER NRN L.P. ONLY FCST
CHANGES WERE TO ADJUST SHORT-TERM POPS BASED ON LATEST TRENDS.
UPDATE ISSUED AT 1112 AM EDT MON AUG 20 2012
A TROPOPAUSE PV ANOMALY IS OVER WI WITH ITS RELATED SFC TROF
SINKING SEWD ACROSS ERN LAKE SUPERIOR INTO THE CNTRL U.P. A
MODEST 60 KT JET STREAK IS ASSOCIATED WITH THE PV ANOMALY. IT
REMAINS COOL ALOFT WITH H5 TEMPS -18C THIS MRNG. WE`RE ALREADY
NOTING AN INCREASE IN SHWR ACTIVITY ON LAKE SUP FROM NEAR CARIBOU
ISLAND DOWN TO PARADISE. THIS LINES UP WELL WITH SPC WRF-NMM AND
THE RAP ENSEMBLE PROBS FOR .01" QPF. POPS WERE UPGRADED WITH THIS
UPDATE WITH ADDITIONAL INCORPORATION OF THIS GUIDANCE FOR THIS
AFTN. WE`VE NOW MENTIONED POTENTIAL FOR SCT SHWRS OVER THE ERN
U.P. AND THE POTENTIAL FOR A SHWR OR TWO NEAR M-72 AND OVER NE
LOWER E OF I-75. DESPITE COOL AIR ALOFT...LAPSE RATES AND MSTR ARE
UNIMPRESSIVE. HOWEVER...THE NAM/GFS DEPICT A POOL OF H85 MSTR OVER
LAKE SUP...NOT SAMPLED BY THE 12Z GRB/APX SOUNDINGS. SO LOW-LVL
MOISTENING WILL INCREASE POTENTIAL A TAD FOR FAIRLY HIGH-BASED
SHWRS. THUNDER? PROBABLY NOT GIVEN MINIMAL INSTABILITY.
UPDATE ISSUED AT 910 AM EDT MON AUG 20 2012
RADAR IS NOW IN VCP 221 FOR MORE RAPID UPDATES AND ENHANCED
VELOCITY DETECTION TO MONITOR BUILDING CU OVER NRN LAKE MI. THE
FCST NOW HAS SLGT CHANCE OF SHWRS FROM LAKE MI INTO THE IMMEDIATE
COAST OF NW LOWER MI...AND A SLGT CHANCE OF WATERSPOUTS OVER THE
NEARSHORE WATERS.
UPDATE ISSUED AT 840 AM EDT MON AUG 20 2012
A QUICK UPDATE HAS BEEN PUBLISHED FOR THE SHWR THAT`S MOVING THRU
PETOSKEY. ALSO INCREASED SKY TO P/CLOUDY OVER FAR NE LWR MI. WE`RE
WATCHING THE LAND BREEZE BOUNDARIES OVER NRN LAKE MI. IF SHWRS
FORM...WE`LL BE ISSUING AN SMW FOR WATERSPOUTS.
UPDATE ISSUED AT 624 AM EDT MON AUG 20 2012
NO UPDATES NEEDED THIS MORNING...STILL BATTLING PESKY MID/UPPER
LEVEL CLOUDS ACROSS THE NRN HALF OF THE CWA. OTHERWISE...JUST SOME
PATCHY FOG IN LOW LYING AREAS. INTERESTINGLY...THERE ARE IN FACT
SOME UPPER 30S TEMPERATURES OUT THERE...WITH GRAYLING COMING IN AT
38 DEGREES....ATLANTA 36 DEGREES AND JUST SOUTH OF US...LEOTA ALSO
AT 36 DEGREES. QUITE THE CHILLY START TO WHAT WILL BE ANOTHER
BEAUTIFUL NRN MICHIGAN SUMMER DAY.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 400 AM EDT MON AUG 20 2012
CLOSED UPPER LOW IS FINALLY STARTING TO MOVE EAST OF JAMES BAY
THIS MORNING...WHILE YET ANOTHER WEAK SFC TROUGH IS SINKING DOWN
THROUGH LAKE SUPERIOR. THERE ARE EMBEDDED SHORTWAVES THAT ARE
ROTATING AROUND THE BACKSIDE OF THE UPPER LOW...AND INTO THE GREAT
LAKES REGION. NONE OF THESE WAVES ARE PRODUCING ANY SIGNIFICANT
FORCING ALOFT. HOWEVER...THERE IS A BAND OF HIGHER LEVEL CLOUDS
DROPPING THROUGH NRN LOWER. TEMPERATURES HAVE PLUMMETED INTO THE
LOWER 40S...AND THERE ARE LIKELY SOME LOCALIZES SPOTS IN THE UPPER
30S. TEMPERATURES WERE AS MILD AS THE MIDDLE 50S NEAR THE WARMER
GREAT LAKES.
TODAY...MOST AREAS WILL BE ABLE TO START OFF WITH DECENT SUNSHINE
THIS MORNING...AND THE CHILLY TEMPERATURES WILL SPIKE UP RATHER
QUICKLY. WINDS WILL OVERALL BE OUT OF THE WEST AND NORTHWEST...BUT
BEING RELATIVELY LIGHT...LAKE BREEZES ARE EXPECTED TO ONCE AGAIN
FIRE OFF THIS AFTERNOON...AND MAKE IT ALL THE WAY INTO THE
INTERIOR HIGHER TERRAIN OF NRN LOWER. THERE WILL BE A BIT MORE OF
A WESTERLY BREEZE ACROSS EASTERN UPPER AHEAD OF THE SFC TROUGH
WHICH WILL SETTLE INTO THIS AREA. HOWEVER...THE TAIL END OF THE
TROUGH WILL BECOME MORE UNDEFINED WITH TIME AS IT WASHES OUT WITH
THE EASTWARD TREK OF THE UPPER LOW. THEREFORE...EVEN THESE WINDS
ARE EXPECTED TO LOOK MORE LIKE LAKE BREEZES THIS AFTERNOON. THESE
TWO CONVERGENCE AREAS WILL BE THE FOCUS FOR ANY PRECIPITATION THAT
TRIED TO GENERATE TODAY. ONE SHORTWAVE THAT IS DROPPING DUE SOUTH
THROUGH WESTERN ONTARIO ATTM...WILL SHARPEN UP WHAT WILL
ULTIMATELY BE THE FINAL MID LEVEL TROUGH AXIS TO ROLL THROUGH.
THIS MID LEVEL TROUGH...COUPLED WITH THE SFC TROUGH/LAKE BREEZE
CONVERGENCE IN EASTERN UPPER...WILL RESULT IN A SLIGHT CHANCE OF
SHOWERS IN EASTERN UPPER. THE AIR MASS IS NOT OVERLY MOIST PER
LATEST APX SOUNDINGS...HOWEVER THERE WAS AN ISOLATED SHOWER THAT
FIRED UP ON THE LAKE BREEZE LATE IN THE DAY YESTERDAY IN NE LOWER.
DON`T SEE WHY THIS COULDN`T HAPPEN IN EASTERN UPPER TODAY...SINCE
THE SYNOPTIC SETUP IS THERE.
WHATEVER DOES DEVELOP LATE THIS AFTERNOON...WON`T LAST LONG. LOSS
OF HEATING AND DEPARTURE OF SAID SHORTWAVE/MID LEVEL TROUGH AXIS
WILL LIKELY NOT PRODUCE ANYTHING AFTER 9PM...BUT NW MID LEVEL
STEERING FLOW COULD SEND A SHOWER OUT OVER THE STRAITS/NRN LAKES
MICHIGAN AND HURON. AFTER THIS...MID LEVEL HEIGHT RISES AND MORE
INFLUENCE FROM THE HIGH PRESSURE TO THE WEST WILL RESULT IN
GRADUALLY CLEARING SKIES OVERNIGHT. TEMPERATURES WILL BE ABLE TO
FALL INTO READINGS SIMILAR TO THIS MORNING...AS WE REMAIN IN THE
LOW LEVEL COOL POOL THROUGH DAYBREAK WITH LIGHT WINDS. SO..EXPECT
ANOTHER CHILLY ONE WITH MAYBE SOME PATCHY FOG IN THE LOWEST OF
AREAS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 400 AM EDT MON AUG 20 2012
TUESDAY...THE 500 MB WAVE CONTINUES TO MOVE THROUGH THE FLOW, AND
WITH RIDGE TO THE WEST FORCING THE HEIGHTS TO CONTINUE TO RISE,
CLOUDS MOVE INTO E UPPER, HOWEVER, THE MODELS SEEM TO INDICATE THAT
THE RAIN SHOULD REMAIN IN ONTARIO NORTH OF THE SOO, JUST BASED ON
THE 700-500 MB LAYER RH AND THE 850 MB RH FIELDS.
TUESDAY NIGHT...THE MODELS CONTINUE TO KEEP THIS SYSTEM NORTH OF THE
SOO AND IN N LAKE SUPERIOR. ALTHOUGH NOW THE GFS IS BRINGING IT
CLOSER TO E UPPER. HOWEVER, IT LOOKS LIKE NAM/ECMWF SOLUTION LOOKS
MORE REASONABLE WITH THE MOISTURE IN THE 700-500MB LAYER A LITTLE
MORE NORTH THAN THE GFS, WHICH HAS BEEN THE TREND OVER THE LAST
SEVERAL RUNS.
WEDNESDAY...WITH THE SFC HIGH MOVES EAST, AND THE COLD FRONT BEGINS
TO PUSH SOUTH WITH SOME WEAK REINFORCEMENT FROM THE 500 MB LOW TO
THE NORTH. SO WILL HAVE SOME WEAK CHANCE POPS IN E UPPER NEAR THE
BOUNDARY AND WAVE. THE MOISTURE THINS QUITE A BIT OVERNIGHT, SO
WON`T BE SURPRISED IF THIS IS JUST A FIGMENT OF THE MODELS
IMAGINATION.
EXTENDED (THURSDAY THROUGH SUNDAY)...THURSDAY, THE FRONT SAGS INTO N
LOWER SO THE WEAK CHANCES FOR RAIN SHOWERS AND IS OVER THE FORECAST
AREA, ESPECIALLY NE LOWER WHERE IT IS CLOSER TO THE 500 MB LOW. HIGH
PRESSURE BUILDS INTO THE REGION OVERNIGHT. HOWEVER, THE MAIN ACTION
LOOKS LIKE IT WON`T ARRIVE UNTIL FRIDAY. THE NEXT SYSTEM ON FRIDAY
MOVES OUT OF THE PLAINS AND INTO THE WESTERN GREAT LAKES. WITH THE
STALLED BOUNDARY, AND SOME MOISTURE AT 850 MB (AT LEAST ON THE
ECMWF) THUNDERSTORM BECOME A POSSIBILITY DURING THE DAY, AND A
BETTER ONE AT NIGHT. THE GFS REALLY DEVELOPS THE SFC FEATURE NORTH
OF LAKE SUPERIOR, SO THINK THAT THERE IS SOME FEEDBACK ISSUES, AND
THAT THE ECMWF LOOKS MORE REALISTIC. SATURDAY, MODELS ARE SHOWING
SOME DIFFERING OPINIONS ON THE WAY THIS SYSTEM WILL EVOLVE. THE 00Z
ECMWF HAS BACKED OFF THE FROPA UNTIL SUNDAY, AND PROBABLY WILL BE
MORE A MONDAY THING. IT IS LOOKING LIKE SOME TROPICAL SYSTEM IS
AFFECTING THE SPEED OF THE FRONT. SO WILL LEAVE THE DAY AND NIGHT
WITH CHANCES. SUNDAY, MODELS BOTH HAVE THE FRONT TRYING TO MOVE INTO
THE FORECAST AREA, OR ALREADY HAVE MOVED INTO THE REGION. WILL
CONTINUE SOME SORT OF CHANCES, BUT IF THERE IS A TROPICAL SYSTEM
MOVING INTO THE GULF COAST AS HINTED BY BOTH, THIS MAY BE ENOUGH TO
DELAY THE RAIN AND FROPA FOR ANOTHER DAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 154 PM EDT MON AUG 20 2012
REST OF THIS AFTN: VFR SCT-BKN CU/FRACTO CU. HEATING-DRIVEN SHWRS
COULD RESULT IN A FEW SPRINKLES OR A BRIEF SHWR AT APN. HAVE
INTRODUCED A VCSH. WORST CASE SCENARIO WOULD BE A DIRECT HIT WHICH
COULD BRIEFLY REDUCE VSBYS TO MVFR. WE`LL CONT TO MONITOR AND
ISSUE AMENDMENTS IF NEEDED. STILL EXPECT LAKE BREEZE TO MAKE IT
INLAND TO APN. OTHERWISE...W WINDS 5-15 KTS PLN-TVC-MBL.
CONFIDENCE HIGH ALL ELEMENTS.
TNGT: PREDOMINANTLY VFR...EXCEPT MVFR FOG EXPECTED AT MBL WITH
AVERAGE CONFIDENCE. THREAT FOR SHWRS ENDS AT APN. SOME MID- LEVEL
CLOUD DEBRIS WILL REMAIN AND GRADUALLY DECREASE FROM REMNANT
DAYTIME CLOUDS. SEVERAL MODELS SUGGEST A SHWR COULD THREATEN PLN
06-12Z. NOTHING IN THE TAF ATTM SINCE IT`S A LOW PROB. CALM WINDS.
CONFIDENCE HIGH ALL ELEMENTS...EXCEPT FOG AT MBL.
TUE THRU 18Z: VFR. FEW-SCT CU REDEVELOPS BY 15Z. W WIND 5-10 KTS
BUT PROBABLY GIVES WAY TO LAKE BREEZES AT TVC-APN.
&&
.MARINE...
ISSUED AT 400 AM EDT MON AUG 20 2012
HIGH PRESSURE WILL WORK ACROSS THE MISSISSIPPI VALLEY AND INTO THE
SRN GREAT LAKES/OHIO VALLEY REGION OVER THE NEXT FEW DAYS. WINDS
WILL BE SUB-ADVISORY THROUGH TUESDAY...WITH LAKE BREEZES IN THE
AFTERNOONS. THE GRADIENT TIGHTENS UP A BIT TUESDAY NIGHT THROUGH
WEDNESDAY WITH A WSW WIND NEARING ADVISORY LEVELS OVER LAKE
MICHIGAN. THIS WILL BE AHEAD OF A COLD FRONT THAT WILL SAG INTO
THE GREAT LAKES AND BRING A CHANCE FOR SHOWERS AND THUNDERSTORMS
LATER THIS WEEK.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...HALBLAUB
SYNOPSIS...JL
SHORT TERM...SD
LONG TERM...JL
AVIATION...HALBLAUB
MARINE...SD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
145 PM EDT MON AUG 20 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 435 AM EDT MON AUG 20 2012
WATER VAPOR IMAGERY AND RUC ANALYSIS CONTINUE TO SHOW A DEEP TROF
DOMINATING THE ERN CONUS WITH THE TROF ANCHORED BY A MID/UPPER LEVEL
CYCLONE CENTERED IN THE VCNTY OF JAMES BAY. THE UPPER LAKES REMAIN
FIRMLY UNDER THE INFLUENCE OF THE TROF. ONE SHORTWAVE IS CURRENTLY
DROPPING THRU MN/NW WI WHILE ANOTHER IS UPSTREAM IN NORTHERN
ONTARIO. NOT MUCH IS HAPPENING WITH FIRST WAVE. AHEAD OF THE LATTER
WAVE...CANADIAN RADAR IMAGERY SHOWS SOME RETURNS IN THE VCNTY OF
LAKE NIPIGON THRU FAR ERN LAKE SUPERIOR. CLOUDS ARE NOW BEGINNING TO
DEVELOP S INTO UPPER MI. UP TO THIS POINT...MOSTLY CLEAR SKIES AND
LIGHT/CALM WIND HAS ALLOWED TEMPS TO FALL INTO THE MID/UPPER 30S IN
THE TRADITIONAL INTERIOR COLD SPOTS EARLY THIS MORNING.
WITH UPPER MI STILL UNDER THE INFLUENCE OF THE MID/UPPER TROF TODAY
AND TONIGHT...MAIN FCST ISSUE IS WHETHER ANY PCPN WILL OCCUR. AS
SHORTWAVE OVER NRN ONTARIO STREAKS S INTO THE AREA TODAY...IT
APPEARS THERE WILL BE ISOLD/SCT -SHRA...ESPECIALLY SINCE THERE ARE
ALREADY SOME -SHRA/SPRINKLES AHEAD OF FEATURE TO THE N OF LAKE
SUPERIOR. SINCE SHORTWAVE DROPS ACROSS WRN UPR MI AND INTO WI IN
THE AFTN...FCST AREA WILL BE ON THE FAVORABLE CYCLONIC SIDE OF
WAVE/UPPER JET STREAK. ARRIVAL DURING PEAK HEATING ARGUES FOR AT
LEAST ISOLD -SHRA MENTION OVER THE CNTRL/ERN FCST AREA. THE
SCNTRL/SE AREAS SHOULD HAVE BEST POTENTIAL FOR -SHRA AS LAKE BREEZE
COMPONENT TO THE WIND WILL INCREASE LOW-LEVEL CONVERGENCE IN THAT
AREA. WITH 850MB TEMPS IN THE 7 TO 9C RANGE...EXPECT MAX TEMPS
GENERALLY WITHIN A FEW DEGREES OF 70F.
ANY -SHRA OVER THE SCNTRL/SE FCST AREA WILL END QUICKLY THIS EVENING
AS SHORTWAVE EXITS THE AREA. WAA WILL THEN BEGIN TO GET UNDERWAY
TONIGHT AS ERN TROF RELAXES. MAIN PUSH OF WAA IS WELL TO THE N...SO
DON`T ANTICIPATE ANY PCPN CONCERNS. MAY SEE SOME MID CLOUDS. ANOTHER
NIGHT OF LIGHT/CALM WINDS WILL RESULT IN A COOL NIGHT. WITH
PRECIPITABLE WATER A LITTLE HIGHER THAN RECENT NIGHTS...MINS SHOULD
BE A BIT HIGHER. TEMPS SHOULD RANGE FROM THE 50S ALONG LAKE SUPERIOR
TO THE 40S INLAND. PROBABLY WON`T SEE ANY 30S AS HAS OCCURRED IN
RECENT NIGHTS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 435 AM EDT MON AUG 20 2012
OKAY AGREEMENT FROM THE MODELS WITH OVERALL LARGE SCALE PATTERN
THROUGH NEXT WEEKEND. STARTING THE LONG RANGE...TWO PRIMARY TROUGHS
ARE IN PLACE...ONE OVER MUCH OF EASTERN CANADA AND THE EASTERN CONUS
WITH OTHER DIGGING INTO PACIFIC NORTHWEST. RIDGE RESIDES IN BETWEEN
THE TWO WITH AXIS FROM SOUTHWEST CONUS NORTH TOWARD THE CANADIAN
ROCKIES. EASTERN CANADA TROUGH GRADUALLY LOSES AMPLITUDE OVER GREAT
LAKES...BUT THIS TAKES A WHILE...PROBABLY NOT UNTIL WED OR THU. ALL
THE WHILE...TROUGH OVER PACIFIC NORTHWEST SLOWLY MOVES INTO THE
UPPER RIDGE WITH SOME SUCCESS. ARRIVAL OF THE UPPER TROUGH OVER
UPPER MISSISSIPPI RIVER VALLEY IS SLATED FOR SOMETIME THU OR FRI.
GFS HAS HAD GOOD RUN-TO-RUN CONTINUITY WITH THIS FEATURE. LAST
COUPLE RUNS OF GEM-NHEM AND ECMWF ARE SHOWING THIS IDEA AS WELL
WHICH ADDS INCREASED CONFIDENCE TO THE SCENARIO.
ONCE THIS TROUGH MOVES THROUGH...EVEN A SHARPER TROUGH IS FORECAST
TO SLIDE THROUGH ACROSS SOUTH CENTRAL CANADA NEXT WEEKEND. THIS
LARGER SCALE TROUGH IS EVENTUALLY FORECAST TO DEVELOP AGAIN FROM
EASTERN CANADA INTO THE GREAT LAKES BY EARLY NEXT WEEK. AT THE
SURFACE...MAIN BOUNDARY LOOKS TO DROP INTO UPPER GREAT LAKES
WEDNESDAY. DESPITE THE FRONTAL BOUNDARY...STRONGER H85 TEMPERATURE
AND MOISTURE ADVECTION AFFECTS LAKE SUPERIOR TUESDAY NIGHT THEN
HEADS MORE EASTERLY ON WEDNESDAY. MODELS HINT THAT THERE MAY BE
ENOUGH H85-H7 MOISTURE POOLING ALONG THE FRONT TO COMBINE WITH
DAYTIME HEATING/SURFACE BASED CAPES AOA 500J/KG TO FORM SOME
SHRA/TSRA BY AFTERNOON. GFS IS BY FAR THE MOST BULLISH IN THIS IDEA.
OTHER MODELS PRETTY MUCH SHOVE NOTABLE MOISTURE TOO FAR EAST TO
DEVELOP MUCH OVER UPR MICHIGAN. PUNTED AND KEPT GOING SLIGHT
CHANCE POPS IN THE FORECAST ALONG THE FRONT...JUST DID NOT HAVE
REAL CONFIDENCE IN MAKING SIGNIFICANT CHANGES ON WEDNESDAY.
WITH LACK OF STEERING FLOW ALOFT...THIS FRONT MAY STALL OUT IN THE
VICINITY OF UPPER MICHIGAN THROUGH THU AND FRI.
BEST CHANCE OF RAIN IN THE LONG TERM PERIOD WILL BE ON FRIDAY
INTO SATURDAY AS PLAINS UPPER TROUGH AND INCREASING H85 MOISTURE
ADVECTION INTERACTS WITH THE SURFACE FRONT ALREADY IN THE AREA. THIS
BY NO MEANS REPRESENTS THE ONLY CHANCE OF RAIN THOUGH. ADDITIONAL
RAIN CHANCES /LOWER RANGE AT THIS POINT/ ARE IN THE FORECAST
WEDNESDAY AND THURSDAY AS ANY LOW-MID LEVEL RIPPLE ALONG THE SURFACE
BOUNDARY COULD KICK OFF ISOLD SHRA/TSRA SINCE RIBBON OF H85-H7
MOISTURE LINGERS OVER THE AREA. ALSO COULD SEE A PERIOD OF SHRA/TSRA
LATE IN THE WEEKEND INTO VERY EARLY NEXT WEEK AS THE STRONGER UPPER
LOW OVER SOUTH CENTRAL CANADA DRAWS CLOSER TO THE AREA ALONG WITH
ANOTHER ROUND OF LOW-LEVEL TEMP/MOISTURE ADVECTION PRECEEDING IT.
FORECAST TEMPERATURES THROUGH THE LONG TERM WILL SHOW WARMING TREND.
CLOUDS/PRECIP COULD IMPACT THE WARMING ANY DAY FROM THURSDAY THROUGH
END OF LONGER TERM...BUT GIVEN H85 TEMPS CLIMBING AOA +15C THINK
TRENDING TEMPS WARMER IS A GOOD STRATEGY. EXPECT HIGHS UPPER 70S TO
LOWER 80S WEDNESDAY THROUGH FRIDAY...WITH POSSIBLY EVEN WARMER TEMPS
WEDNESDAY AND/OR THURSDAY IF CLOUDS/PRECIP TURN OUT TO BE NOT MUCH
OF A FACTOR. MORE WARMTH EXPECTED FOR THE UPCOMING WEEKEND OUT AHEAD
OF THE DEEPER TROUGH OVER CENTRAL CANADA. GENERAL SW WIND AND H85
TEMPS AROUND +17C SUGGEST WIDESPREAD 80S COULD OCCUR...AGAIN IF
CLOUDS AND PRECIP ARE NOT AN ISSUE. TOUGH TO SAY HOW WEEKEND WILL
TURN OUT THOUGH. GFS IS QUITE AGREESSIVE IN CLEARING LEADING SYSTEM
OUT FRIDAY NIGHT WHILE ECMWF IS SOMEWHAT SLOWER. GFS STAYS QUICK IN
BRINGING NEXT BATCH OF SHRA/TSRA INTO UPR LAKES BY SUNDAY WHILE
ECMWF IS AGAIN SLOWER. CONSENSUS HAS TO WORK FOR NOW FOR POPS GIVEN
THESE DIFFERENCES...BUT DID GO AHEAD AND INCREASE TEMPS OVER THE
CONSENSUS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 144 PM EDT MON AUG 20 2012
ISOLATED TO SCATTERED SHOWERS OVER PARTS OF UPPER MI WILL SLOWLY
MOVE S OVER THE REST OF THE DAYTIME HOURS...THEN DIMINISH AFTER LOSS
OF DAYTIME HEATING. SHOWERS SHOULD BE CLEAR OF CMX BY START OF THIS
TAF PERIOD. AT SAW...EXPECT SHOWERS ACTIVITY IN THE VICINITY TO
BECOME MORE NUMEROUS AROUND 20Z...AND LAST FOR A COUPLE OF HOURS.
LESS CONFIDENT OF PRECIP CHANCES AT IWD...WHICH IS FARTHER FROM THE
SHORTWAVE ENERGY PARTIALLY RESPONSIBLE FOR THE SHOWERS...SO INCLUDED
VCSH THROUGH MID EVENING. RELATIVELY DRY LOW-LEVELS WILL ALSO KEEP
CONDITIONS VFR AT KIWD/KCMX THRU THE FCST PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 435 AM EDT MON AUG 20 2012
WEAK PRESSURE GRADIENT DOMINATES UPPER GREAT LAKES MOST OF THIS WEEK
INTO NEXT WEEKEND SO EXPECT WINDS AOB 20 KTS. ONLY EXCEPTION COULD
BE LATER TUESDAY INTO TUESDAY NIGHT AS SOUTHWEST WINDS MAY GUST TO
25 KTS OVER WESTERN AND NORTH CENTRAL LK SUPERIOR OUT AHEAD OF FRONT
DROPPING IN FROM NORTHERN ONTARIO. CHANCES FOR ANY SHRA/TSRA WILL BE
SPOTTY UNTIL STRONGER DISTURBANCE BRINGS GOOD CHANCE OF SHRA/TSRA TO
THE REGION FRIDAY INTO NEXT WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...TITUS
MARINE...JLA
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
116 PM EDT MON AUG 20 2012
.SYNOPSIS...
ISSUED AT 339 AM EDT MON AUG 20 2012
ONE FINAL WAVE OF LOW PRESSURE IN THE SERIES WILL MOVE THROUGH THE
AREA TODAY AND THIS EVENING. THIS IS EXPECTED TO PRODUCE SOME
SHOWERS SOUTH OF I-96...WITH SOME SPRINKLES POSSIBLE ELSEWHERE. HIGH
PRESSURE IS THEN EXPECTED TO BUILD IN ACROSS THE AREA. THIS WILL
PROVIDE THE AREA WITH DRY CONDITIONS AND WARMING TEMPERATURES
THROUGH THE WEEK.
&&
.UPDATE...
ISSUED AT 1108 AM EDT MON AUG 20 2012
DID NOT MAKE SIGNIFICANT CHANGES TO THE GOING FORECAST BUT DID ADD
THE MENTION OF THUNDER ALONG THE I-94 CORRIDOR. SPC DAY ONE
OUTLOOK HAS GENERAL THUNDER IN THIS AREA AND CANNOT ARGUE.
MODIFYING THE MORNING SOUNDING FROM DTX TO A TEMP/DEW POINT OF
74/52 YIELDS CAPE VALUES IN THE 600-1000 J/KG RANGE AND LI/S AS
LOW AS -2 TO -3C. SHORTWAVE SEEN IN THE WATER VAPOR IMAGERY
DROPPING TOWARD LAKE SUPERIOR REACHES CENTRAL LAKE MICHIGAN JUST
AFTER MAX HEATING AND IT MAY BE ENOUGH TO ADD SOME SYNOPTIC SCALE
LIFT TO THINGS AS WELL. MESOSCALE MODELS...THE HRRR AND THE 4KM
WRF RUNS FROM SPC AND NSSL ALL INDICATE SOME ISOLATED TO SCATTERED
ACTIVITY DEVELOPING NEAR THE OLD FRONT TOWARD THE MICHIGAN/INDIANA
BORDER REGION AND ALONG THE LAKE BREEZE FRONT. BOTTOM LINE...HAVE
ISOLATED (20 PCT) ACROSS THE NORTHERN 3/4 OF THE AREA AND
SCATTERED (25 PCT) POPS TOWARDS I94. HIGHS SHOULD TOP OUT IN THE
MID TO UPPER 70S IN MOST AREAS.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 339 AM EDT MON AUG 20 2012
THE FIRST PERIOD OF THE FCST IS REALLY THE ONLY PERIOD IN WHICH ANY
WEATHER IS EXPECTED...AND THE IMPACT OF THE FIRST PERIOD WEATHER
SHOULD BE RATHER LIMITED WITH SHOWER POTENTIAL THE MAIN FOCUS.
WE ARE SEEING FOG DEVELOPING UP NORTH EARLY THIS MORNING AS EXPECTED
WHERE THERE WAS MORE WIDESPREAD RAINFALL YESTERDAY. THE MORE DENSE
FOG IS STILL RATHER LIMITED WITH ONLY KMOP AND KAMN REPORTING 1/2 TO
1/4SM THUS FAR IN THE CWFA. FOG IR SATELLITE IMAGERY INDICATES THAT
IT IS NOT WIDESPREAD ACROSS ANY OF OUR COUNTIES UP NORTH YET. WE
WILL CONTINUE TO MONITOR THE FOG THIS MORNING FOR ANY POSSIBLE
HEADLINES.
ONCE THE FOG IS GONE BY MID MORNING...THE FOCUS WILL TURN TO PCPN
CHCS. THERE IS ONE MORE UPPER WAVE THAT IS POISED TO MOVE THROUGH
THE REGION LATER TODAY AND TONIGHT. THIS WAVE IS CURRENTLY
APPROACHING LAKE SUPERIOR AND HEADING SOUTH. THIS WAVE IS EXPECTED
TO AMPLIFY A BIT AS IT MOVES IN. THE ISSUE IS THERE IS NOT A LOT OF
MOISTURE LEFT IN THE AREA TO WORK WITH AS THE FRONT THAT MOVED
THROUGH YESTERDAY TOOK THE BETTER MOISTURE WITH IT.
LOW LEVEL MOISTURE IS LACKING ACROSS MOST OF THE CWFA ASIDE FROM THE
FOG THIS MORNING...WITH THE BEST MOISTURE BEING FOUND ACROSS THE FAR
SRN PORTION OF THE CWFA. WE AGREE WITH THE MODELS THAT THE BEST CHCS
WILL BE SOUTH OF I-96. WE CAN NOT RULE OUT ANYTHING ELSEWHERE...BUT
IT WOULD LIKELY BE RATHER LIGHT WITH LIMITED LOW LEVEL MOISTURE. WE
HAVE GONE WITH SPRINKLES ELSEWHERE EXPECTING THEY WILL BE FALLING
FROM HIGHER CLOUD BASES.
WE CAN NOT RULE OUT THUNDER ALONG THE I-94 CORRIDOR AS MODELS SHOW
LI/S DROPPING TO AROUND 0 OR BARELY BELOW. FCST SOUNDINGS INDICATE
THAT WE WILL REALLY NOT SEE ANY CAPE ABOVE THE -20C ISOTHERM. THE
THREAT SEEMS TOO LOW AT THIS TIME TO ADD THUNDER IN.
ONCE THE DIURNAL INSTABILITY WANES THIS EVENING...WE EXPECT
CONDITIONS WILL BECOME DRY OVERNIGHT. THE TROUGH WILL STILL BE
PUSHING THROUGH. THE TROUGH AXIS WILL BE JUST ABOUT READY TO EXIT
THE CWFA AT 12Z TUE. AFTER THAT...WE WILL SEE UPPER RIDGING BUILD IN
ACROSS THE AREA. THIS WILL LAST THROUGH THE DAY ON WED AND LIKELY
BEYOND. TEMPS WILL MODERATE INTO THE 80S AS H850 TEMPS WARM TO THE
MID TEENS C.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 339 AM EDT MON AUG 20 2012
THE MAIN STORYLINE FOR THE LONG TERM PERIOD IS THAT WARMER THAN
NORMAL TEMPERATURES WILL RETURN AND STICK AROUND FOR AWHILE. THIS IS
IN RESPONSE TO RISING HEIGHTS AND LOW LEVEL SOUTHWEST FLOW.
WHILE NOT ZERO... THE CHANCE OF SHOWERS AND TSTMS LOOKS PRETTY LOW
THROUGH THE PERIOD. SFC RIDGING STILL DOMINATES ON THURSDAY... AND
THE SFC WARM FRONT IS EXPECTED TO BE SITUATED WELL TO OUR NORTH OVER
THE WEEKEND.
ONE FEATURE TO KEEP AN EYE ON IN FUTURE MODEL RUNS WILL BE A
NEGATIVELY TILTED H5 SHORTWAVE WHICH IS CURRENTLY PROGGED TO PASS
THROUGH THE REGION FRIDAY NIGHT AND SATURDAY. RIGHT NOW IT APPEARS
THAT THE BEST FORCING WITH THIS FEATURE WILL STAY TO OUR NORTHWEST
AND THAT THE WAVE WILL BE DEAMPLIFYING AS IT MOVES EAST.
ANOTHER SHORTWAVE IS PROGGED TO APPROACH FROM THE SOUTHWEST ON
SUNDAY AND WARRANTS KEEPING LOW CHANCE POPS IN THE FCST ATTM.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 116 PM EDT MON AUG 20 2012
A FEW HIT AND MISS POP UP SHOWERS ARE EXPECTED INTO THE HEAT OF
THE DAY...GENERALLY AFTER 20Z. INSTABILITY MAY BE STRONG ENOUGH TO
PRODUCE A FEW LIGHTNING STRIKES SOUTH OF I-96. ANY PCPN WILL
QUICKLY COME TO AN END SHORTLY AFTER SUNSET. VFR CONDITIONS ARE
EXPECTED OUTSIDE OF ANY SHOWER/STORMS...WITH QUIET WEATHER
CONTINUING INTO EARLY TUESDAY.
&&
.MARINE...
ISSUED AT 339 AM EDT MON AUG 20 2012
THE ONLY CONCERN FOR MARINE INTERESTS WITH THIS FCST PACKAGE IS THE
CHC OF WATERSPOUTS AGAIN TODAY. A LAND BREEZE IS DEVELOPING THIS
MORNING...WHICH COULD CAUSE A BAND OF CLOUDS/SHOWERS THAT WOULD HAVE
THE POTENTIAL TO PRODUCE WATERSPOUTS. THE INSTABILITY AND POTENTIAL
CLOUD DEPTH OVER THE LAKE WOULD BE SUFFICIENT. WE ARE NOT SURE IF
THEY WILL COME TO FRUITION DUE TO THE UNCERTAINTY OF THE SHOWERS.
&&
.HYDROLOGY...
ISSUED AT 339 AM EDT MON AUG 20 2012
NO HYDROLOGY ISSUES ARE EXPECTED IN THE NEXT FEW DAYS AS A PERIOD OF
DRY WEATHER IS FORECAST FOR THE AREA. CHANCES OF RAIN WILL GRADUALLY
INCREASE LATE IN THE SEVEN DAY PERIOD...HOWEVER NOTHING LOOKS
NOTEWORTHY WITH REGARDS TO FLOODING AT THIS TIME.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...DUKE
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...MEADE
AVIATION...JK
HYDROLOGY...NJJ
MARINE...NJJ
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
640 PM EDT MON AUG 20 2012
.SYNOPSIS...
A WEAK FRONTAL SYSTEM WILL TRIGGER A FEW SHOWERS AND THUNDERSTORMS
ACROSS THE AREA INTO THIS EVENING. HIGH PRESSURE WILL FOLLOW
BEHIND THE FRONT... BRINGING MOSTLY DRY WARM WEATHER TUESDAY
THROUGH THE REST OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
615 PM UPDATE...NUMEROUS SHOWERS CONTINUE OVER THE WYOMING VALLEY
NORTHEAST ACROSS THE POCONOS INTO THE SOUTHERN CATSKILLS, WITH
SCATTERED ACTIVITY BACK ACROSS CENTRAL NEW YORK. THIS CONVECTION
IS BEING FORCED BY A MID LEVEL SHORT IN SOUTHWEST UPPER LEVEL
FLOW. AS THIS FEATURE CONTINUES MOVING NORTHEAST THIS EVENING THE
ACTIVITY WILL GRADUALLY DIMINISH. TEMPS HAVE COOLED RAPIDLY LATE
THIS AFTERNOON DUE TO THE SHOWERY WEATHER, READINGS NOW ARE
GENERALLY IN THE MID TO UPPER 60S. SHORT TERM ADJ TO
TEMPS/CLOUDS/POPS, REST UNCHANGED.
.PREVIOUS DISC...
LATEST WATER VAPOR LOOP CONFIRMS A WEAK SHORT WAVE TRACKING
NORTHEAST FROM THE MID-ATLANTIC STATES TOWARD NEW ENGLAND THIS
AFTERNOON. A BROKEN BAND OF SHOWERS WITH ISOLATED THUNDER HAS
DEVELOPED ACROSS EASTERN PA NORTHEAST TO THE CATSKILLS THIS
AFTERNOON... AND THIS WILL TRACK SLOWLY EAST ACROSS OUR
SOUTHEASTERN COUNTIES THROUGH THIS EVENING. MEANWHILE A FEW
SCATTERED TO ISOLATED SHOWERS WILL PERSIST FARTHER TO THE WEST
UNDER THE UPPER TROUGH THROUGH EARLY THIS EVENING. CURRENT
FORECAST REFLECTS THIS SCENARIO WITH LIKELY POPS FOR NORTHEAST PA
AND THE CATSKILLS INTO EARLY THIS EVENING... AND CHANCE POPS
FARTHER WEST. SEVERE THREAT WITH ANY THUNDERSTORM INTO THIS
EVENING LOOKS VERY LOW WITH WEAK WIND FIELDS AND LATEST RUC SHORT
TERM FORECASTS INDICATING CAPE VALUES GENERALLY LESS THAN 300
J/KG. RAINFALL THUS FAR WITH THESE SHOWERS HAS BEEN LESS THAN AN
INCH AND WITH THE PROGRESSIVE NATURE OF THESE SHOWERS OBSERVED SO
FAR TODAY AM NOT EXPECTING ANY EXCESSIVE RAINFALL INTO THIS
EVENING.
EXPECT AREAS OF FOG AND STRATUS TO FORM LATER TONIGHT WITH SOME
CLEARING AND PLENTY OF LOW-LEVEL MOISTURE LEFT OVER FROM TODAYS
SHOWERS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
TUESDAY LOOKS LIKE A LESS CONVECTIVELY ACTIVE DAY THAN TODAY WITH
SLIGHT DRYING BEHIND TODAY`S SYSTEM RESULTING IN LITTLE IF ANY
INSTABILITY ON AREA FORECAST SOUNDINGS. HOWEVER STILL CAN`T RULE
OUT AN ISOLATED SHOWERS GIVEN THAT THE UPPER TROUGH WILL REMAIN
JUST TO THE WEST THROUGH THE DAY. BASED ON THIS HAVE GONE WITH
POPS GENERALLY FROM 15 TO 25 PERCENT TUESDAY AFTERNOON. FEWER
CLOUDS IN MOST PLACES WILL RESULT IN SLIGHTLY WARMER
TEMPERATURES... ESPECIALLY ACROSS THE TWIN TIERS WHERE CLOUDS KEPT
TEMPERATURES DOWN QUITE A BIT TODAY. EXPECT HIGHS MAINLY NEAR OR
JUST ABOVE 80.
QUIET PATTERN CONTINUES TUESDAY NIGHT THROUGH THURSDAY AS HIGH
PRESSURE SETTLES IN ACROSS THE AREA. CONDITIONS WILL BE DRY WITH
AMPLE DAYTIME SUNSHINE... HIGH TEMPERATURES NEAR OR JUST ABOVE 80
AND LOWS MOSTLY IN THE 50S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
2 PM TUE UPDATE...
A RIDGE OF HIGH PRESSURE SFC AND ALOFT ALONG THE EAST COAST WILL
BE IN CONTROL FOR MOST OF THE EXTENDED. TIMING DIFFERENCES ON WHEN
THIS WILL BREAK DOWN ENOUGH TO LET SHOWERS AND THUNDERSTORMS FORM
DURING THE WEEKEND. LATER A COLD FRONT WILL MOVE THROUGH TUESDAY.
THE GFS IS FASTER BY 12 TO 24 HOURS OVER THE EURO.
TEMPERATURES START NEAR NORMAL THEN RISE TO BE ABOVE NORMAL FOR
THE WEEKEND AND NEXT WEEK. FOLLOWED HPC GUIDANCE.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
A COMBINATION OF LIGHT WIND FLOW AND MOIST ANTECEDENT CONDITIONS
WILL LEAD TO PATCHY FOG EARLY TUESDAY MORNING. THE BEST CHANCE FOR
FOG AT A LOCAL TERMINAL WILL BE AT ELM, WHERE TEMPO 1/2SM FOG IS
FORECAST BETWEEN 8Z AND 12Z.
THERE IS A LOWER CHANCE FOR IFR FOG AT BGM. IF FOG DEVELOPS, IT
IS LIKELY THE VIS RESTRICTION WILL BE IN THE 1SM TO 3SM RANGE WITH
A BROKEN 600-900FT DECK OVERHEAD.
LIGHT WINDS AND VFR CONDITIONS ARE FORECAST FOR TUESDAY AFTERNOON.
THERE IS A SLIGHT CHANCE FOR A THUNDERSTORM NEAR AVP, BUT THE ODDS
ARE VERY LOW THAT THE TERMINAL WILL BE DIRECTLY AFFECTED.
OUTLOOK...
TUE NGT TO SAT...MAINLY VFR. MRNG VLY IFR FOG PSBL AT KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...MSE/RRM
SHORT TERM...MSE
LONG TERM...TAC
AVIATION...DJP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
635 PM EDT MON AUG 20 2012
.SYNOPSIS...
A WEAK FRONTAL SYSTEM WILL TRIGGER A FEW SHOWERS AND THUNDERSTORMS
ACROSS THE AREA INTO THIS EVENING. HIGH PRESSURE WILL FOLLOW
BEHIND THE FRONT... BRINGING MOSTLY DRY WARM WEATHER TUESDAY
THROUGH THE REST OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
615 PM UPDATE...NUMEROUS SHOWERS CONTINUE OVER THE WYOMING VALLEY
NORTHEAST ACROSS THE POCONOS INTO THE SOUTHERN CATSKILLS, WITH
SCATTERED ACTIVITY BACK ACROSS CENTRAL NEW YORK. THIS CONVECTION
IS BEING FORCED BY A MID LEVEL SHORT IN SOUTHWEST UPPER LEVEL
FLOW. AS THIS FEATURE CONTINUES MOVING NORTHEAST THIS EVENING THE
ACTIVITY WILL GRADUALLY DIMINISH. TEMPS HAVE COOLED RAPIDLY LATE
THIS AFTERNOON DUE TO THE SHOWERY WEATHER, READINGS NOW ARE
GENERALLY IN THE MID TO UPPER 60S. SHORT TERM ADJ TO
TEMPS/CLOUDS/POPS, REST UNCHANGED.
.PREVIOUS DISC...
LATEST WATER VAPOR LOOP CONFIRMS A WEAK SHORT WAVE TRACKING
NORTHEAST FROM THE MID-ATLANTIC STATES TOWARD NEW ENGLAND THIS
AFTERNOON. A BROKEN BAND OF SHOWERS WITH ISOLATED THUNDER HAS
DEVELOPED ACROSS EASTERN PA NORTHEAST TO THE CATSKILLS THIS
AFTERNOON... AND THIS WILL TRACK SLOWLY EAST ACROSS OUR
SOUTHEASTERN COUNTIES THROUGH THIS EVENING. MEANWHILE A FEW
SCATTERED TO ISOLATED SHOWERS WILL PERSIST FARTHER TO THE WEST
UNDER THE UPPER TROUGH THROUGH EARLY THIS EVENING. CURRENT
FORECAST REFLECTS THIS SCENARIO WITH LIKELY POPS FOR NORTHEAST PA
AND THE CATSKILLS INTO EARLY THIS EVENING... AND CHANCE POPS
FARTHER WEST. SEVERE THREAT WITH ANY THUNDERSTORM INTO THIS
EVENING LOOKS VERY LOW WITH WEAK WIND FIELDS AND LATEST RUC SHORT
TERM FORECASTS INDICATING CAPE VALUES GENERALLY LESS THAN 300
J/KG. RAINFALL THUS FAR WITH THESE SHOWERS HAS BEEN LESS THAN AN
INCH AND WITH THE PROGRESSIVE NATURE OF THESE SHOWERS OBSERVED SO
FAR TODAY AM NOT EXPECTING ANY EXCESSIVE RAINFALL INTO THIS
EVENING.
EXPECT AREAS OF FOG AND STRATUS TO FORM LATER TONIGHT WITH SOME
CLEARING AND PLENTY OF LOW-LEVEL MOISTURE LEFT OVER FROM TODAYS
SHOWERS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
TUESDAY LOOKS LIKE A LESS CONVECTIVELY ACTIVE DAY THAN TODAY WITH
SLIGHT DRYING BEHIND TODAY`S SYSTEM RESULTING IN LITTLE IF ANY
INSTABILITY ON AREA FORECAST SOUNDINGS. HOWEVER STILL CAN`T RULE
OUT AN ISOLATED SHOWERS GIVEN THAT THE UPPER TROUGH WILL REMAIN
JUST TO THE WEST THROUGH THE DAY. BASED ON THIS HAVE GONE WITH
POPS GENERALLY FROM 15 TO 25 PERCENT TUESDAY AFTERNOON. FEWER
CLOUDS IN MOST PLACES WILL RESULT IN SLIGHTLY WARMER
TEMPERATURES... ESPECIALLY ACROSS THE TWIN TIERS WHERE CLOUDS KEPT
TEMPERATURES DOWN QUITE A BIT TODAY. EXPECT HIGHS MAINLY NEAR OR
JUST ABOVE 80.
QUIET PATTERN CONTINUES TUESDAY NIGHT THROUGH THURSDAY AS HIGH
PRESSURE SETTLES IN ACROSS THE AREA. CONDITIONS WILL BE DRY WITH
AMPLE DAYTIME SUNSHINE... HIGH TEMPERATURES NEAR OR JUST ABOVE 80
AND LOWS MOSTLY IN THE 50S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
2 PM TUE UPDATE...
A RIDGE OF HIGH PRESSURE SFC AND ALOFT ALONG THE EAST COAST WILL
BE IN CONTROL FOR MOST OF THE EXTENDED. TIMING DIFFERENCES ON WHEN
THIS WILL BREAK DOWN ENOUGH TO LET SHOWERS AND THUNDERSTORMS FORM
DURING THE WEEKEND. LATER A COLD FRONT WILL MOVE THROUGH TUESDAY.
THE GFS IS FASTER BY 12 TO 24 HOURS OVER THE EURO.
TEMPERATURES START NEAR NORMAL THEN RISE TO BE ABOVE NORMAL FOR
THE WEEKEND AND NEXT WEEK. FOLLOWED HPC GUIDANCE.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
2 PM UPDATE...
MAINLY VFR SHOULD CONTINUE INTO TONIGHT. MVFR IS POSSIBLE IN THE
HEAVIER SHOWERS BUT FOR NOW SHOWERS HAVE ONLY INCREASED IN
COVERAGE TO SCATTERED. FOR THE NEXT 2 HOURS THE MOST LIKELY TAF
SITE FOR THIS WILL BE KAVP. THUNDERSTORMS MOVING INTO THE OTHER
END OF THE COUNTY NOW HEADING NE TO KAVP.
THIS EVE...CLOUDS SHOULD GRADUALLY CLEAR FROM NW TO SE...AS A WEAK
FRONT EASES ACROSS THE REGION. WITH SHOWERS ALMOST EVERYWHERE SOME
VALLEY FOG SHOULD FORM LATE TONIGHT AT KELM. MVFR IS LIKELY WITH
IFR POSSIBLE THERE. MVFR VSBY FOG IS POSSIBLE AT KAVP AND KBGM.
NE TO SW SFC FRONT THROUGH THE CWA SO WINDS VARIABLE AND LIGHT.
TONIGHT WINDS 5 KTS OR LESS AND VARIABLE. W TO NW WINDS AT 5 KTS.
OUTLOOK...
TUE...VFR...WITH BRIEF RESTRICTIONS PSBL IN THE AFTN FROM ISOLD
SHRA/TSRA MAINLY AT KAVP.
WED TO SAT...MAINLY VFR. MRNG VLY IFR FOG PSBL AT KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...MSE/RRM
SHORT TERM...MSE
LONG TERM...TAC
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
333 PM EDT MON AUG 20 2012
.SYNOPSIS...
A WEAK FRONTAL SYSTEM WILL TRIGGER A FEW SHOWERS AND THUNDERSTORMS
ACROSS THE AREA INTO THIS EVENING. HIGH PRESSURE WILL FOLLOW
BEHIND THE FRONT... BRINGING MOSTLY DRY WARM WEATHER TUESDAY
THROUGH THE REST OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
LATEST WATER VAPOR LOOP CONFIRMS A WEAK SHORT WAVE TRACKING
NORTHEAST FROM THE MID-ATLANTIC STATES TOWARD NEW ENGLAND THIS
AFTERNOON. A BROKEN BAND OF SHOWERS WITH ISOLATED THUNDER HAS
DEVELOPED ACROSS EASTERN PA NORTHEAST TO THE CATSKILLS THIS
AFTERNOON... AND THIS WILL TRACK SLOWLY EAST ACROSS OUR
SOUTHEASTERN COUNTIES THROUGH THIS EVENING. MEANWHILE A FEW
SCATTERED TO ISOLATED SHOWERS WILL PERSIST FARTHER TO THE WEST
UNDER THE UPPER TROUGH THROUGH EARLY THIS EVENING. CURRENT
FORECAST REFLECTS THIS SCENARIO WITH LIKELY POPS FOR NORTHEAST PA
AND THE CATSKILLS INTO EARLY THIS EVENING... AND CHANCE POPS
FARTHER WEST. SEVERE THREAT WITH ANY THUNDERSTORM INTO THIS
EVENING LOOKS VERY LOW WITH WEAK WIND FIELDS AND LATEST RUC SHORT
TERM FORECASTS INDICATING CAPE VALUES GENERALLY LESS THAN 300
J/KG. RAINFALL THUS FAR WITH THESE SHOWERS HAS BEEN LESS THAN AN
INCH AND WITH THE PROGRESSIVE NATURE OF THESE SHOWERS OBSERVED SO
FAR TODAY AM NOT EXPECTING ANY EXCESSIVE RAINFALL INTO THIS
EVENING.
EXPECT AREAS OF FOG AND STRATUS TO FORM LATER TONIGHT WITH SOME
CLEARING AND PLENTY OF LOW-LEVEL MOISTURE LEFT OVER FROM TODAYS
SHOWERS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
TUESDAY LOOKS LIKE A LESS CONVECTIVELY ACTIVE DAY THAN TODAY WITH
SLIGHT DRYING BEHIND TODAY`S SYSTEM RESULTING IN LITTLE IF ANY
INSTABILITY ON AREA FORECAST SOUNDINGS. HOWEVER STILL CAN`T RULE
OUT AN ISOLATED SHOWERS GIVEN THAT THE UPPER TROUGH WILL REMAIN
JUST TO THE WEST THROUGH THE DAY. BASED ON THIS HAVE GONE WITH
POPS GENERALLY FROM 15 TO 25 PERCENT TUESDAY AFTERNOON. FEWER
CLOUDS IN MOST PLACES WILL RESULT IN SLIGHTLY WARMER
TEMPERATURES... ESPECIALLY ACROSS THE TWIN TIERS WHERE CLOUDS KEPT
TEMPERATURES DOWN QUITE A BIT TODAY. EXPECT HIGHS MAINLY NEAR OR
JUST ABOVE 80.
QUIET PATTERN CONTINUES TUESDAY NIGHT THROUGH THURSDAY AS HIGH
PRESSURE SETTLES IN ACROSS THE AREA. CONDITIONS WILL BE DRY WITH
AMPLE DAYTIME SUNSHINE... HIGH TEMPERATURES NEAR OR JUST ABOVE 80
AND LOWS MOSTLY IN THE 50S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
2 PM TUE UPDATE...
A RIDGE OF HIGH PRESSURE SFC AND ALOFT ALONG THE EAST COAST WILL
BE IN CONTROL FOR MOST OF THE EXTENDED. TIMING DIFFERENCES ON WHEN
THIS WILL BREAK DOWN ENOUGH TO LET SHOWERS AND THUNDERSTORMS FORM
DURING THE WEEKEND. LATER A COLD FRONT WILL MOVE THROUGH TUESDAY.
THE GFS IS FASTER BY 12 TO 24 HOURS OVER THE EURO.
TEMPERATURES START NEAR NORMAL THEN RISE TO BE ABOVE NORMAL FOR
THE WEEKEND AND NEXT WEEK. FOLLOWED HPC GUIDANCE.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
2 PM UPDATE...
MAINLY VFR SHOULD CONTINUE INTO TONIGHT. MVFR IS POSSIBLE IN THE
HEAVIER SHOWERS BUT FOR NOW SHOWERS HAVE ONLY INCREASED IN
COVERAGE TO SCATTERED. FOR THE NEXT 2 HOURS THE MOST LIKELY TAF
SITE FOR THIS WILL BE KAVP. THUNDERSTORMS MOVING INTO THE OTHER
END OF THE COUNTY NOW HEADING NE TO KAVP.
THIS EVE...CLOUDS SHOULD GRADUALLY CLEAR FROM NW TO SE...AS A WEAK
FRONT EASES ACROSS THE REGION. WITH SHOWERS ALMOST EVERYWHERE SOME
VALLEY FOG SHOULD FORM LATE TONIGHT AT KELM. MVFR IS LIKELY WITH
IFR POSSIBLE THERE. MVFR VSBY FOG IS POSSIBLE AT KAVP AND KBGM.
NE TO SW SFC FRONT THROUGH THE CWA SO WINDS VARIABLE AND LIGHT.
TONIGHT WINDS 5 KTS OR LESS AND VARIABLE. W TO NW WINDS AT 5 KTS.
OUTLOOK...
TUE...VFR...WITH BRIEF RESTRICTIONS PSBL IN THE AFTN FROM ISOLD
SHRA/TSRA MAINLY AT KAVP.
WED TO SAT...MAINLY VFR. MRNG VLY IFR FOG PSBL AT KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...MSE
SHORT TERM...MSE
LONG TERM...TAC
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
255 PM EDT MON AUG 20 2012
.SYNOPSIS...
A SLOW MOVING FRONT...IN COMBINATION WITH AN UPPER LEVEL
DISTURBANCE...WILL BRING THE CHANCE FOR SHOWERS AND ISOLATED
THUNDERSTORMS TO THE REGION TODAY. A STALLED FRONT TO OUR EAST AND
AN UPPER LEVEL DISTURBANCE COULD TRIGGER A FEW ISOLATED SHOWERS OR
EVEN THUNDERSTORMS TUESDAY AFTERNOON...ESPECIALLY IN NORTHEAST
PENNSYLVANIA. HIGH PRESSURE WILL BUILD INTO THE REGION FOR
WEDNESDAY AND WEDNESDAY NIGHT WITH FAIR WEATHER EXPECTED.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED AT 1030 AM... CURRENTLY TRACKING WAVES WHICH WILL BE
GENERATING AREAS OF SHOWERS MOVING NORTHEAST ACROSS THE AREA IN
SOUTHWEST FLOW ALOFT TODAY. FIRST BATCH OF SHOWERS IS NOW MOVING
FROM BRADFORD COUNTY TOWARD BROOME... SUSQUEHANNA AND TIOGA
COUNTIES WITH LIGHTER SHOWERS ALSO DEVELOPING TO THE NORTHWEST AND
SOUTHEAST OF THE MAIN AREA OF SHOWERS. MODELS CONTINUE TO INDICATE
FAVORABLE CONDITIONS FOR WEAK LIFT ACROSS MOST OF THE AREA TODAY
WITH A WEAK BAND OF MID-LEVEL FRONTOGENESIS ORIENTED FROM
SOUTHWEST TO NORTHEAST ACROSS UPSTATE NY. BASED ON THIS EXPECT
THIS FIRST BATCH OF SHOWERS TO HOLD TOGETHER AND MOVE NORTHEAST
TOWARD THE WESTERN CATSKILLS EARLY THIS AFTERNOON... WHILE OTHER
AREAS OF SHOWERS CONTINUE TO DEVELOP ELSEWHERE ACROSS THE CWA.
CURRENT POPS ARE REFLECTING THIS SCENARIO WITH HIGH LIKELY TO
CATEGORICAL SPREADING FROM SUSQUEHANNA COUNTY PA TOWARD THE
CATSKILLS... WHILE HIGH CHC POPS DEVELOP ELSEWHERE ACROSS THE AREA
THROUGH MID- AFTERNOON. PREVIOUS DISCUSSION BELOW.
UPDATE AT 7 AM...QUICK UPDATE TO ADJUST POPS AND TIMING...WINDS
AND TEMPS JUST TWEAKS. NO MAJOR CHANGES TO THE NEAR TERM.
UPDATED AS OF 4 AM...MINOR CHANGES TO POPS AS CONVECTIVE ACTVTY HAS
RAPIDLY DIMINISHED IN WRN NY UPON REACHING C NY. I DON/T EXPECT
MUCH MORE ACTVY UNTIL LATER OVERNIGHT WHEN SOME ISLD ACVTY CUD
REACH NE PA. OTHERWISE NO MAJOR CHANGES FROM EARLIER UPDATE.
PREVIOUS DSCN BELOW...
RADAR SHOWS SCATTERED PATCHES OF SHOWERS AND ISOLATED
THUNDERSTORMS MOVING NORTHEAST FROM PA INTO SC NY EARLY THIS
MORNING. THIS ACVTY WAS BEING SUPPORTED BY A SMALL UPPER LEVEL
RIPPLE SEEN WELL IN THE WATER VAPOR SATELLITE IMAGERY. THIS UPPER
LEVEL FEATURE WAS MOVING NORTHEAST TWD PA AND NY FROM WEST
VIRGINIA AND SUPPORTED A WEAK SFC LO OVER SERN OH. THIS UPPER
LEVEL WAVE AND ASSCTD SFC FEATURE WILL CONTINUE TO MOVE NORTHEAST
EARLY THIS MORNING BEFORE GETTING CAUGHT UP IN AN UPPER LEVEL
CONFLUENCE ZONE THAT WAS HANGING TOUGH BETWEEN AND STATIONARY
UPPER LEVEL LOW OVER JAMES BAY CANADA AND THE EVER PRESENT
SUBTROPICAL UPPER LEVEL RIDGE COMMON THIS TIME OF YEAR WELL OFF
THE EAST COAST. THUS THE WAVE AND ASSCTD SFC FEATURE WILL SHEAR
OUT BTWN 6Z AND 12Z AND THE PRECIPITATION THAT IT WAS SUPPORTING
WILL WEAKEN AS IT MOVES FARTHER NORTH AND EAST. TRENDS ON RADAR
INDICATE THIS. WATER VAPOR IMAGERY SHOWS IT WELL.
THE ONLY MODEL THAT SEEMS TO HAVE SOMEWHAT OF A HANDLE ON THE QPF
WITH THIS WEAK SYSTEM IS THE GFS...KEEPING SOME LIGHT QPF ACROSS
MUCH OF CENTRAL NY UNTIL ARND 6Z BEFORE WEAKENING IT. THE NAM HAS
NO PRECIP...THE LATEST CONVECTION ALLOWING HI RES WRF ARW AND WRF
NMM DO NOT HAVE ANY PRECIP TONIGHT FOR OUR AREA. THE RAP IS DOING A
BETTER JOB BUT HAS TOO MUCH COVERAGE SIMILAR TO THE GFS BUT MORE
IN NRN PA WHEN MOST OF THE ACVTY IS IN THE WRN PART OF NY. MODEL
SOUNDINGS ALL SHOW SOME WEAK COOLING ALOFT WITH THIS WAVE INITIALLY
BTWN 600 AND 500 MB WHICH ON SOME MODEL SOUNDINGS IS STILL CAPPED
BUT ON THE GFS AND SREF SOUNDINGS ARE NOT. THE RUC ALSO ALLOWS FOR
SOME SMALL CAPE. SO IT IS A VERY MARGINAL SITUATION FOR PRECIP.
ALL MODELS TREND THIS ACVTY DOWN OVERNIGHT SO WILL GO ALONG WITH
THAT TREND USING CURRENT RADAR TRENDS WHICH IS AN IMPROVEMENT OVER
THE MODELS. THERE IS SOME ELEVATED CAPE SO MAYBE A RUMBLE OF
THUNDER...BUT NOTHING SIGNIFICANT OVERNIGHT.
FOR TODAY...ANOTHER SHORT WAVE MO/IL WILL ROUND THE BASE OF THE
UPPER LEVEL TROF OVER THE GREAT LAKES AND OH VLLY AND LIFT
NORTHEASTWARD TODAY. THIS FEATURE WILL SUPPORT LIFTG AND COOLING
AT MID-LEVELS COINCIDENT WITH THE DAYTIME HEATING SUPPORTG SCT
SHWRS AND TSRA FORMING DURG THE DAY INTO THE AFTERNOON. CAPES ON
ALL MODELS ARE MARGINAL RUNNING ONLY IN THE HUNDREDS...GENERALLY
LESS THAN 500 J/KG. THE SHEAR IS WEAK BELOW 6 KM WHICH IS WHERE
MOST OF THE CAPE IS...SO THE EFFECTIVE SHEAR IS WEAK. THERE IS
STRONGER SHEAR ALOFT FROM 6KM ON UP BUT DO NOT BELIEVE WITH SUCH
LOW CAPE VALUES THAT WE WILL SEE ANY SVR WEATHER. ANY STORM THAT
CAN REACH THESE HIGHER ALTITUDES LIKELY WILL GET SHEARED OUT
ANYWAY. SO JUST HAVE CHC POPS FOR LATER IN THE DAY INTO THE
AFTERNOON.
SHOWERS AND THUNDERSTORMS WILL WANE QUICKLY THIS EVENING AS THIS
NEXT SHORTWAVE SHEARS OUT IN THIS EVER PRESENT CONFLUENT ZONE
OVERHEAD TONIGHT. THIS OCCURS COINCIDENT WITH THE LOSS OF THE
DAY/S HEATING. FURTHERMORE WITH STRGR UPPER CONFLUENCE...A SFC
RIDGE WILL FORM OVER THE REGION...LEADING TO SOME POTENTIAL
CLEARING. WILL MONITOR FOR POTENTIAL VALLEY FOG LATE TONIGHT WITH
SHORT TERM UPDATE COMING SOON.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
TUESDAY WILL BEGIN WITH SCT-BKN MID-HI CLDS ARND AS A STRUNG OUT
FRONTL SYSTEM IS STALLED OFFSHORE WITH A DEPARTING SFC WAVE. THE
CMC AND NAM ARE STRONGEST WITH THE SFC WAVE DEVELOPMENT WITH THE
EURO AND GFS MUCH MORE WEAKER FLATTER WITH THE PRESSURE FIELD
OFFSHORE. THIS MAKES A DIFFERENCE FOR OUR AREA IN THAT THE NAM AND
CMC HAVE A STRONGER LL HIGH PRESSURE SYSTEM OVER OUR AREA TUESDAY
WHICH TENDS TO SUPRESS CONVECTIVE DEVELOPMENT. THE NAM MODEL
SOUNDINGS FOR TUESDAY DON/T PRODUCE ANY SIGNIFICANT CAPE AND APPEAR
CAPPED TO SOME EXTENT BY A MID-LVL INVERSION. THE EURO AND GFS
HAVE A WEAKER SFC PRESSURE RDG OVER OUR AREA WITH MORE LOW-LEVEL
MOISTURE HANGING ARND. THE GFS SOUNDINGS DO GENERATE CAPE WITH THE
AFTERNOON HEATING SUGGESTIVE OF ISLD TO SCT SHRA AND EVEN SOME
TSRA. LI/S ARE SLIGHTLY NEGATIVE ON THE GFS WITH CAPES IN THE
HUNDREDS AGAIN....MAINLY FROM THE SRN TIER INTO NRN PA. SO NOTHING
MAJOR. WIND SHEARS ARE WEAK AND CAPE IS NOT IMPRESSIVE SO WILL
HAVE ISLD TO SCT SHRA AND TSRA WITH HIGHEST POPS IN NE PA AND
LOWER POPS AS YOU TRAVEL N INTO NC NY WHERE CAPE IS MINIMAL.
FOR TUESDAY NIGHT...ALL CONVECTIVE ACVTY WINDS DOWN WITH LOSS OF
DAY/S HEATING. SFC HIGH PRESSURE DOMINATES ON ALL MODELS AND THERE
IS LARGE SCALE SUBSC. SO WILL WIND DOWN ANY RESIDUAL POPS FROM THE
EARLY EVENING.
FOR WEDNESDAY AND WEDNESDAY NIGHT...HIGH PRESSURE TAKES CONTROL WITH
LARGE SCALE SUBSC AND MORE STBL AIR IN PLACE. SO WED CUD BE THE
NICEST DAY OF THIS FORECAST PD.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
2 PM TUE UPDATE...
A RIDGE OF HIGH PRESSURE SFC AND ALOFT ALONG THE EAST COAST WILL
BE IN CONTROL FOR MOST OF THE EXTENDED. TIMING DIFFERENCES ON WHEN
THIS WILL BREAK DOWN ENOUGH TO LET SHOWERS AND THUNDERSTORMS FORM
DURING THE WEEKEND. LATER A COLD FRONT WILL MOVE THROUGH TUESDAY.
THE GFS IS FASTER BY 12 TO 24 HOURS OVER THE EURO.
TEMPERATURES START NEAR NORMAL THEN RISE TO BE ABOVE NORMAL FOR
THE WEEKEND AND NEXT WEEK. FOLLOWED HPC GUIDANCE.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
2 PM UPDATE...
MAINLY VFR SHOULD CONTINUE INTO TONIGHT. MVFR IS POSSIBLE IN THE
HEAVIER SHOWERS BUT FOR NOW SHOWERS HAVE ONLY INCREASED IN
COVERAGE TO SCATTERED. FOR THE NEXT 2 HOURS THE MOST LIKELY TAF
SITE FOR THIS WILL BE KAVP. THUNDERSTORMS MOVING INTO THE OTHER
END OF THE COUNTY NOW HEADING NE TO KAVP.
THIS EVE...CLOUDS SHOULD GRADUALLY CLEAR FROM NW TO SE...AS A WEAK
FRONT EASES ACROSS THE REGION. WITH SHOWERS ALMOST EVERYWHERE SOME
VALLEY FOG SHOULD FORM LATE TONIGHT AT KELM. MVFR IS LIKELY WITH
IFR POSSIBLE THERE. MVFR VSBY FOG IS POSSIBLE AT KAVP AND KBGM.
NE TO SW SFC FRONT THROUGH THE CWA SO WINDS VARIABLE AND LIGHT.
TONIGHT WINDS 5 KTS OR LESS AND VARIABLE. W TO NW WINDS AT 5 KTS.
OUTLOOK...
TUE...VFR...WITH BRIEF RESTRICTIONS PSBL IN THE AFTN FROM ISOLD
SHRA/TSRA MAINLY AT KAVP.
WED TO SAT...MAINLY VFR. MRNG VLY IFR FOG PSBL AT KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...MSE
SHORT TERM...
LONG TERM...TAC
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
304 PM EDT MON AUG 20 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH PARKED OVER THE MISSISSIPPI VALLEY WILL
CONTINUE TO BRING COOLER AND MORE UNSETTLED WEATHER TO THE AREA
THROUGH THE END OF THE WEAK BEFORE HIGHER PRESSURE MOVES IN FOR THE
WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
AS OF 240 PM MONDAY...
CURRENTLY THE UPPER LEVEL TROUGH IS PARKED OVER THE MISSISSIPPI
VALLEY WITH A PARENT UPPER LEVEL LOW OVER NORTHERN QUEBEC. AT THE
SURFACE CENTRAL NC IS CURRENTLY IN A VERY WEAK GRADIENT BETWEEN A
MESO-LOW EXITING TO THE NORTHEAST AND SURFACE HIGH TO THE NORTHWEST.
THIS HAS RESULTED IN VERY WEAK FLOW AT THE SURFACE. MOST STRATUS
LEFT FROM THIS MORNING HAS ERODED AND ALLOWED A BROKEN CUMULUS FIELD
TO DEVELOP ACROSS THE STATE. SOME VERY LIGHT SHOWERS ARE BEGINNING
TO POP UP ESPECIALLY IN NORTHEASTERN SECTIONS OF THE CWA. BACK TO
THE NORTHWEST...A STRONGER LINE OF CONVECTION HAS DEVELOPED OFF OF
THE VIRGINIA MOUNTAINS AND IS SLOWLY WORKING SOUTHEASTWARD. WHETHER
OR NOT DYNAMICS ARE GOOD ENOUGH TO SUSTAIN THIS ACTIVITY INTO THE
NORTHWEST PIEDMONT REMAINS TO BE SEEN. THE HRRR MODEL DOES RESOLVE
THIS FEATURE AND BRINGS BRIEF SHOWERS AND STORMS INTO THE TRIAD BY
22Z. ASIDE FROM THE FAR NORTHWEST...BULK SHEAR IS HIGH ACROSS THE
STATE (50-60 KNOTS) DUE TO AN EXITING UPPER LEVEL JET. ALMOST ALL OF
THIS SHEAR IS IN THE UPPER ELEVATIONS AS SHEAR IN THE LOWER LEVELS
IS ALMOST NOT EXISTENT. ALTHOUGH INSTABILITY IS SOMEWHAT LACKING
ACROSS THE CWA THERE SHOULD BE AT LEAST 500 J TO WORK WITH AND WITH
CONVECTIVE TEMPERATURES AT ONLY 76 DEGREES...SHOWERS HAVE NOT HAD
TROUBLE INITIATING BUT THE QUESTION REMAINS ON HOW FAR THEY CAN
DEVELOP. DEWPOINTS STRUGGLING TO STAY IN THE MID 60S IN THE
NORTHWEST WITH UPPER 60S SOUTHEAST. THIS AFTERNOON EXPECT SOME
SHOWERS AND STORMS TO DEVELOP...ESPECIALLY IN THE EAST. DO NOT
EXPECT MUCH IN THE WAY OF SEVERE ACTIVITY ALTHOUGH IF IT WERE TO
OCCUR THE MAIN THREAT WOULD BE DAMAGING WINDS. SKINNY CAPE PROFILES
DO NOT SUPPORT HAIL VERY WELL ALTHOUGH FREEZING LEVELS ARE LOWER
THAN IN PREVIOUS DAYS AT 13.5 KFT. MAXIMUM TEMPERATURES THIS
AFTERNOON WILL TOP OUT IN THE LOWER 80S.
TONIGHT HIGH RESOLUTION MODELS DO TRY TO CONTINUE OF WAVE OF
CONVECTION OFF THE MOUNTAINS BUT THIS SHOULD STRUGGLE TO SURVIVE
WITH LACK OF DAYTIME HEATING. THE BIGGER PROBLEM FOR THE OVERNIGHT
HOURS...ESPECIALLY IN THE EAST WILL BE AREAS OF FOG WHICH COULD
BEGIN JUST AFTER 9Z AND COULD REMAIN THROUGH SUNRISE. AN SPS OR
DENSE FOG ADVISORY WOULD NOT BE OUT OF THE QUESTION EAST OF I-95. IN
THE TRIAD THERE WILL BE LESS MOISTURE TO SUPPORT FOG DEVELOPMENT BUT
SOME VISIBILITY REDUCTIONS DURING THE OVERNIGHT HOURS ARE STILL
POSSIBLE. LOWS OVERNIGHT IN THE MID TO UPPER 60S.
FOR TUESDAY THE CHANCES FOR SEVERE WEATHER FOR TOMORROW AFTERNOON
WILL BE A BIT BETTER WITH MORE INSTABILITY AVAILABLE BUT IT WILL BE
CONFINED TO EASTERN PORTIONS OF THE CWA AND SHOULD STILL BE
ISOLATED. SHEAR WILL STILL BE PLENTIFUL AS THE JET CONTINUES TO MAKE
AN EXIT TO THE NORTHEAST. DURING THE AFTERNOON HOURS A 500 MB VORT
MAX SHOULD MAKE HEADWAY UP THE COAST BUT WHETHER OR NOT THIS FEATURE
PASSES CLOSE ENOUGH TO THE EASTERN PERIPHERY TO HELP SUPPORT
CONVECTION REMAINS TO BE SEEN. SURFACE HIGH PRESSURE TO THE
NORTHWEST WILL START TO WORK INTO THE AREA...POTENTIALLY CONFINING
CONVECTION EVEN FURTHER TO THE EAST DEPENDING ON PROGRESS. WHILE THE
UPPER LEVEL TROUGH WILL STILL BE IN PLACE IT WILL BEGIN TO LIFT OUT
AS THE UPPER JET CONTINUES UP THE EASTERN SEABOARD. MAX TEMPERATURES
TUESDAY WILL BE IN THE LOWER 80S WITH LOWS TUESDAY NIGHT IN THE MID
60S.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 245 PM MONDAY...
WEDNESDAY AND WEDNESDAY NIGHT:
THE LATEST 12Z MODEL GUIDANCE INDICATES SHORTWAVE ENERGY DIGGING
SOUTHEAST THROUGH THE CENTRAL PLAINS ON TUE...AND INTO THE LOWER MS
RIVER VALLEY/DEEP SOUTH ON WED...PROGRESSING EASTWARD INTO THE
SOUTHEAST STATES WED NIGHT...WITH A LOW-LEVEL TROUGH (OR WEAK
SFC-H85 LOW) DOWNSTREAM OVER THE EASTERN CAROLINAS. A SHEAR AXIS IS
EXPECTED TO EXTEND SW-NE ALONG THE APPALACHIANS IN BOTH WED/WED
NIGHT...PROGRESSING SLOWLY EASTWARD TOWARD THE CENTRAL CAROLINAS/VA.
UNCERTAINTY PERSISTS W/REGARD TO THE EVOLUTION OF UPSTREAM SHORTWAVE
ENERGY...LENDING UNCERTAINTY TO THE LOW-LEVEL PATTERN OVER THE
CAROLINAS WED/WED NIGHT. AS A RESULT...A FAIR AMOUNT OF UNCERTAINTY
IS PRESENT WITH TEMPERATURES...CLOUD COVER AND PRECIPITATION
CHANCES...ESPECIALLY DURING THE DAY WED. HOWEVER...MODEL GUIDANCE IS
IN RELATIVELY GOOD AGREEMENT ON THE OVERALL PATTERN...WHICH WOULD
SUGGEST MORE CLOUD COVER...COOLER TEMPERATURES AND BETTER CHANCES
FOR SHOWER ACTIVITY IN EASTERN PORTIONS OF THE AREA. WILL INDICATE
PRECIP CHANCES RANGING FROM 20-40% ON WED (HIGHEST EAST)...WITH
HIGHS IN THE MID 80S WEST TO NEAR 80F EAST. FOR WED NIGHT...MODEL
GUIDANCE INDICATES THE AFOREMENTIONED SHEAR AXIS SLOWLY PROGRESSING
EASTWARD TOWARD THE CENTRAL CAROLINAS...WITH THE MORE POTENT
SHORTWAVE ENERGY OVER THE SOUTHEAST STATES DEAMPLIFYING AS IT
PROGRESSES TOWARD THE SOUTHEAST COAST. WILL INDICATE 20-30% CHANCES
THROUGH MIDNIGHT (HIGHEST EAST)...WITH 20% IN THE COASTAL PLAIN
THROUGH SUNRISE THU...DRY ELSEWHERE. LOWS THU MORNING EXPECTED TO
RANGE FROM THE LOWER 60S (WEST) TO MID/UPPER 60S (EAST). -VINCENT
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 300 PM MONDAY...
THE LATEST LONG RANGE MODEL GUIDANCE INDICATES A CHANGE IN THE
SYNOPTIC PATTERN OVER THE REGION THIS WEEKEND THROUGH EARLY NEXT
WEEK...WITH TROUGHING OVER THE EASTERN CONUS GIVING WAY TO A
STRENGTHENING UPPER LEVEL RIDGE OVER THE EAST COAST...AND
UNSEASONABLY STRONG SURFACE HIGH PRESSURE EXTENDING SOUTHWARD FROM
NEW ENGLAND INTO THE MID-ATLANTIC AND CAROLINAS. THE PRIMARY
UNCERTAINTY W/REGARD TO THE EXTENDED FORECAST APPEARS TO REVOLVE
AROUND THE EVOLUTION OF A POTENTIAL TROPICAL SYSTEM LATE IN THE
EXTENDED PERIOD (EARLY NEXT WEEK). AT THIS POINT...EXPECT NEAR
NORMAL TEMPERATURES AND PRECIP CHANCES ON THU-FRI...FOLLOWED BY NEAR
NORMAL TEMPERATURES AND BELOW NORMAL PRECIP CHANCES OVER THE
WEEKEND. AS MENTIONED ABOVE...UNCERTAINTY INCREASES CONSIDERABLY BY
EARLY NEXT WEEK...AND AT THIS TIME WILL INDICATE CLIMATOLOGICAL
CONDITIONS ON MONDAY. -VINCENT
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 130 PM MONDAY...
24 HOUR TAF PERIOD: CEILINGS ARE BEGINNING TO BREAK THIS AFTERNOON
AS SITES RETURN TO VFR CONDITIONS. THIS TREND WILL CONTINUE OVER THE
NEXT SEVERAL HOURS. THE QUESTION FOR THIS AFTERNOON WILL BE WHETHER
IT BECOMES UNSTABLE ENOUGH TO PRODUCE SHOWERS AND THUNDERSTORMS. THE
MOST LIKELY AREA FOR THIS TO HAPPEN WOULD BE THE SOUTHEAST BUT KGSO
AND KINT MAY BE THREATENED LATER ON AS CONVECTION DEVELOPS OFF OF
THE MOUNTAINS AND THE FOOTHILLS. THE PROBLEM HERE WILL BE THE LOSS
OF DAYTIME HEATING BEFORE CONVECTION ARRIVES AT THE TERMINALS.
OTHERWISE THE PROBLEM OF THE DAY WILL BE 1/2 MILE VISIBILITIES AND
FOG OVERNIGHT. THIS WILL BE MORE PREVALENT FURTHER TO THE EAST AFTER
9Z UNTIL SUNRISE. FURTHER TO THE WEST VISIBILITIES DOWN TO 3 MILES
WILL BE MORE OF A CONCERN. CALM CONDITIONS OVERNIGHT WILL HELP
SUSTAIN FOG DEVELOPMENT. WINDS PICK UP TO 5 KNOTS AFTER SUNRISE AND
FOG SHOULD BURN OFF BY MID-MORNING ON TUESDAY. NO MENTION OF STORMS
IN THE TAF FOR TUESDAY AFTERNOON AT THIS TIME BUT THERE WILL BE A
POSSIBILITY OF SOME CONVECTION...MAINLY EAST OF I-95.
LONG TERM: FOG AND STRATUS WILL BE POSSIBLE ONCE AGAIN ON WEDNESDAY
MORNING. OTHERWISE AFTERNOON SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE IN THE EAST THROUGH THE END OF THE WEEK.A DRYING PATTERN
WILL HELP TO SUSTAIN VFR CONDITIONS THROUGH THE WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...ELLIS
SHORT TERM...VINCENT
LONG TERM...VINCENT
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
253 PM EDT MON AUG 20 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH PARKED OVER THE MISSISSIPPI VALLEY WILL
CONTINUE TO BRING COOLER AND MORE UNSETTLED WEATHER TO THE AREA
THROUGH THE END OF THE WEAK BEFORE HIGHER PRESSURE MOVES IN FOR THE
WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
AS OF 240 PM MONDAY...
CURRENTLY THE UPPER LEVEL TROUGH IS PARKED OVER THE MISSISSIPPI
VALLEY WITH A PARENT UPPER LEVEL LOW OVER NORTHERN QUEBEC. AT THE
SURFACE CENTRAL NC IS CURRENTLY IN A VERY WEAK GRADIENT BETWEEN A
MESO-LOW EXITING TO THE NORTHEAST AND SURFACE HIGH TO THE NORTHWEST.
THIS HAS RESULTED IN VERY WEAK FLOW AT THE SURFACE. MOST STRATUS
LEFT FROM THIS MORNING HAS ERODED AND ALLOWED A BROKEN CUMULUS FIELD
TO DEVELOP ACROSS THE STATE. SOME VERY LIGHT SHOWERS ARE BEGINNING
TO POP UP ESPECIALLY IN NORTHEASTERN SECTIONS OF THE CWA. BACK TO
THE NORTHWEST...A STRONGER LINE OF CONVECTION HAS DEVELOPED OFF OF
THE VIRGINIA MOUNTAINS AND IS SLOWLY WORKING SOUTHEASTWARD. WHETHER
OR NOT DYNAMICS ARE GOOD ENOUGH TO SUSTAIN THIS ACTIVITY INTO THE
NORTHWEST PIEDMONT REMAINS TO BE SEEN. THE HRRR MODEL DOES RESOLVE
THIS FEATURE AND BRINGS BRIEF SHOWERS AND STORMS INTO THE TRIAD BY
22Z. ASIDE FROM THE FAR NORTHWEST...BULK SHEAR IS HIGH ACROSS THE
STATE (50-60 KNOTS) DUE TO AN EXITING UPPER LEVEL JET. ALMOST ALL OF
THIS SHEAR IS IN THE UPPER ELEVATIONS AS SHEAR IN THE LOWER LEVELS
IS ALMOST NOT EXISTENT. ALTHOUGH INSTABILITY IS SOMEWHAT LACKING
ACROSS THE CWA THERE SHOULD BE AT LEAST 500 J TO WORK WITH AND WITH
CONVECTIVE TEMPERATURES AT ONLY 76 DEGREES...SHOWERS HAVE NOT HAD
TROUBLE INITIATING BUT THE QUESTION REMAINS ON HOW FAR THEY CAN
DEVELOP. DEWPOINTS STRUGGLING TO STAY IN THE MID 60S IN THE
NORTHWEST WITH UPPER 60S SOUTHEAST. THIS AFTERNOON EXPECT SOME
SHOWERS AND STORMS TO DEVELOP...ESPECIALLY IN THE EAST. DO NOT
EXPECT MUCH IN THE WAY OF SEVERE ACTIVITY ALTHOUGH IF IT WERE TO
OCCUR THE MAIN THREAT WOULD BE DAMAGING WINDS. SKINNY CAPE PROFILES
DO NOT SUPPORT HAIL VERY WELL ALTHOUGH FREEZING LEVELS ARE LOWER
THAN IN PREVIOUS DAYS AT 13.5 KFT. MAXIMUM TEMPERATURES THIS
AFTERNOON WILL TOP OUT IN THE LOWER 80S.
TONIGHT HIGH RESOLUTION MODELS DO TRY TO CONTINUE OF WAVE OF
CONVECTION OFF THE MOUNTAINS BUT THIS SHOULD STRUGGLE TO SURVIVE
WITH LACK OF DAYTIME HEATING. THE BIGGER PROBLEM FOR THE OVERNIGHT
HOURS...ESPECIALLY IN THE EAST WILL BE AREAS OF FOG WHICH COULD
BEGIN JUST AFTER 9Z AND COULD REMAIN THROUGH SUNRISE. AN SPS OR
DENSE FOG ADVISORY WOULD NOT BE OUT OF THE QUESTION EAST OF I-95. IN
THE TRIAD THERE WILL BE LESS MOISTURE TO SUPPORT FOG DEVELOPMENT BUT
SOME VISIBILITY REDUCTIONS DURING THE OVERNIGHT HOURS ARE STILL
POSSIBLE. LOWS OVERNIGHT IN THE MID TO UPPER 60S.
FOR TUESDAY THE CHANCES FOR SEVERE WEATHER FOR TOMORROW AFTERNOON
WILL BE A BIT BETTER WITH MORE INSTABILITY AVAILABLE BUT IT WILL BE
CONFINED TO EASTERN PORTIONS OF THE CWA AND SHOULD STILL BE
ISOLATED. SHEAR WILL STILL BE PLENTIFUL AS THE JET CONTINUES TO MAKE
AN EXIT TO THE NORTHEAST. DURING THE AFTERNOON HOURS A 500 MB VORT
MAX SHOULD MAKE HEADWAY UP THE COAST BUT WHETHER OR NOT THIS FEATURE
PASSES CLOSE ENOUGH TO THE EASTERN PERIPHERY TO HELP SUPPORT
CONVECTION REMAINS TO BE SEEN. SURFACE HIGH PRESSURE TO THE
NORTHWEST WILL START TO WORK INTO THE AREA...POTENTIALLY CONFINING
CONVECTION EVEN FURTHER TO THE EAST DEPENDING ON PROGRESS. WHILE THE
UPPER LEVEL TROUGH WILL STILL BE IN PLACE IT WILL BEGIN TO LIFT OUT
AS THE UPPER JET CONTINUES UP THE EASTERN SEABOARD. MAX TEMPERATURES
TUESDAY WILL BE IN THE LOWER 80S WITH LOWS TUESDAY NIGHT IN THE MID
60S.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 245 PM MONDAY...
WEDNESDAY AND WEDNESDAY NIGHT:
THE LATEST 12Z MODEL GUIDANCE INDICATES SHORTWAVE ENERGY DIGGING
SOUTHEAST THROUGH THE CENTRAL PLAINS ON TUE...AND INTO THE LOWER MS
RIVER VALLEY/DEEP SOUTH ON WED...PROGRESSING EASTWARD INTO THE
SOUTHEAST STATES WED NIGHT...WITH A LOW-LEVEL TROUGH (OR WEAK
SFC-H85 LOW) DOWNSTREAM OVER THE EASTERN CAROLINAS. A SHEAR AXIS IS
EXPECTED TO EXTEND SW-NE ALONG THE APPALACHIANS IN BOTH WED/WED
NIGHT...PROGRESSING SLOWLY EASTWARD TOWARD THE CENTRAL CAROLINAS/VA.
UNCERTAINTY PERSISTS W/REGARD TO THE EVOLUTION OF UPSTREAM SHORTWAVE
ENERGY...LENDING UNCERTAINTY TO THE LOW-LEVEL PATTERN OVER THE
CAROLINAS WED/WED NIGHT. AS A RESULT...A FAIR AMOUNT OF UNCERTAINTY
IS PRESENT WITH TEMPERATURES...CLOUD COVER AND PRECIPITATION
CHANCES...ESPECIALLY DURING THE DAY WED. HOWEVER...MODEL GUIDANCE IS
IN RELATIVELY GOOD AGREEMENT ON THE OVERALL PATTERN...WHICH WOULD
SUGGEST MORE CLOUD COVER...COOLER TEMPERATURES AND BETTER CHANCES
FOR SHOWER ACTIVITY IN EASTERN PORTIONS OF THE AREA. WILL INDICATE
PRECIP CHANCES RANGING FROM 20-40% ON WED (HIGHEST EAST)...WITH
HIGHS IN THE MID 80S WEST TO NEAR 80F EAST. FOR WED NIGHT...MODEL
GUIDANCE INDICATES THE AFOREMENTIONED SHEAR AXIS SLOWLY PROGRESSING
EASTWARD TOWARD THE CENTRAL CAROLINAS...WITH THE MORE POTENT
SHORTWAVE ENERGY OVER THE SOUTHEAST STATES DEAMPLIFYING AS IT
PROGRESSES TOWARD THE SOUTHEAST COAST. WILL INDICATE 20-30% CHANCES
THROUGH MIDNIGHT (HIGHEST EAST)...WITH 20% IN THE COASTAL PLAIN
THROUGH SUNRISE THU...DRY ELSEWHERE. LOWS THU MORNING EXPECTED TO
RANGE FROM THE LOWER 60S (WEST) TO MID/UPPER 60S (EAST). -VINCENT
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 305 AM MONDAY...
THE ANOMALOUSLY DEEP AND PERSISTENT UPPER TROUGH OVER THE EASTERN
HALF OF THE COUNTRY WILL HAVE WEAKENED SIGNIFICANTLY BY
THURSDAY...WITH A LESS DEFINED/AMPLIFIED UPPER LEVEL TROUGH TO
LINGER THROUGH THE WEEKEND. MODELS GENERALLY AGREE
ON SURFACE HIGH PRESSURE SETTLING OVER THE EAST COAST STATES AND
PERSISTING THROUGH THE PERIOD...WHICH SHOULD YIELD TEMPS RIGHT
AROUND NORMAL IN THE MID 80S FOR HIGH AND LOWS IN THE MID/UPPER
60S. THE GFS IS A BIT MORE ACTIVE THEN THE ECMWF REGARDING
CONVECTION BENEATH THE WEAK UPPER TROUGH EACH DAY...BUT WITH A DRIER
AND LESS UNSTABLE AIRMASS EXPECTED WITH THE SURFACE
HIGH...SHOWERS/STORMS SHOULD BE MAINLY ISOLATED AND TIED TO THE
AFTERNOON SEABREEZE AND DIFFERENTIAL HEATING ALONG THE HIGHER
TERRAIN.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 130 PM MONDAY...
24 HOUR TAF PERIOD: CEILINGS ARE BEGINNING TO BREAK THIS AFTERNOON
AS SITES RETURN TO VFR CONDITIONS. THIS TREND WILL CONTINUE OVER THE
NEXT SEVERAL HOURS. THE QUESTION FOR THIS AFTERNOON WILL BE WHETHER
IT BECOMES UNSTABLE ENOUGH TO PRODUCE SHOWERS AND THUNDERSTORMS. THE
MOST LIKELY AREA FOR THIS TO HAPPEN WOULD BE THE SOUTHEAST BUT KGSO
AND KINT MAY BE THREATENED LATER ON AS CONVECTION DEVELOPS OFF OF
THE MOUNTAINS AND THE FOOTHILLS. THE PROBLEM HERE WILL BE THE LOSS
OF DAYTIME HEATING BEFORE CONVECTION ARRIVES AT THE TERMINALS.
OTHERWISE THE PROBLEM OF THE DAY WILL BE 1/2 MILE VISIBILITIES AND
FOG OVERNIGHT. THIS WILL BE MORE PREVALENT FURTHER TO THE EAST AFTER
9Z UNTIL SUNRISE. FURTHER TO THE WEST VISIBILITIES DOWN TO 3 MILES
WILL BE MORE OF A CONCERN. CALM CONDITIONS OVERNIGHT WILL HELP
SUSTAIN FOG DEVELOPMENT. WINDS PICK UP TO 5 KNOTS AFTER SUNRISE AND
FOG SHOULD BURN OFF BY MID-MORNING ON TUESDAY. NO MENTION OF STORMS
IN THE TAF FOR TUESDAY AFTERNOON AT THIS TIME BUT THERE WILL BE A
POSSIBILITY OF SOME CONVECTION...MAINLY EAST OF I-95.
LONG TERM: FOG AND STRATUS WILL BE POSSIBLE ONCE AGAIN ON WEDNESDAY
MORNING. OTHERWISE AFTERNOON SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE IN THE EAST THROUGH THE END OF THE WEEK.A DRYING PATTERN
WILL HELP TO SUSTAIN VFR CONDITIONS THROUGH THE WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...ELLIS
SHORT TERM...VINCENT
LONG TERM...SMITH
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
244 PM EDT MON AUG 20 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH PARKED OVER THE MISSISSIPPI VALLEY WILL
CONTINUE TO BRING COOLER AND MORE UNSETTLED WEATHER TO THE AREA
THROUGH THE END OF THE WEAK BEFORE HIGHER PRESSURE MOVES IN FOR THE
WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
AS OF 240 PM MONDAY...
CURRENTLY THE UPPER LEVEL TROUGH IS PARKED OVER THE MISSISSIPPI
VALLEY WITH A PARENT UPPER LEVEL LOW OVER NORTHERN QUEBEC. AT THE
SURFACE CENTRAL NC IS CURRENTLY IN A VERY WEAK GRADIENT BETWEEN A
MESO-LOW EXITING TO THE NORTHEAST AND SURFACE HIGH TO THE NORTHWEST.
THIS HAS RESULTED IN VERY WEAK FLOW AT THE SURFACE. MOST STRATUS
LEFT FROM THIS MORNING HAS ERODED AND ALLOWED A BROKEN CUMULUS FIELD
TO DEVELOP ACROSS THE STATE. SOME VERY LIGHT SHOWERS ARE BEGINNING
TO POP UP ESPECIALLY IN NORTHEASTERN SECTIONS OF THE CWA. BACK TO
THE NORTHWEST...A STRONGER LINE OF CONVECTION HAS DEVELOPED OFF OF
THE VIRGINIA MOUNTAINS AND IS SLOWLY WORKING SOUTHEASTWARD. WHETHER
OR NOT DYNAMICS ARE GOOD ENOUGH TO SUSTAIN THIS ACTIVITY INTO THE
NORTHWEST PIEDMONT REMAINS TO BE SEEN. THE HRRR MODEL DOES RESOLVE
THIS FEATURE AND BRINGS BRIEF SHOWERS AND STORMS INTO THE TRIAD BY
22Z. ASIDE FROM THE FAR NORTHWEST...BULK SHEAR IS HIGH ACROSS THE
STATE (50-60 KNOTS) DUE TO AN EXITING UPPER LEVEL JET. ALMOST ALL OF
THIS SHEAR IS IN THE UPPER ELEVATIONS AS SHEAR IN THE LOWER LEVELS
IS ALMOST NOT EXISTENT. ALTHOUGH INSTABILITY IS SOMEWHAT LACKING
ACROSS THE CWA THERE SHOULD BE AT LEAST 500 J TO WORK WITH AND WITH
CONVECTIVE TEMPERATURES AT ONLY 76 DEGREES...SHOWERS HAVE NOT HAD
TROUBLE INITIATING BUT THE QUESTION REMAINS ON HOW FAR THEY CAN
DEVELOP. DEWPOINTS STRUGGLING TO STAY IN THE MID 60S IN THE
NORTHWEST WITH UPPER 60S SOUTHEAST. THIS AFTERNOON EXPECT SOME
SHOWERS AND STORMS TO DEVELOP...ESPECIALLY IN THE EAST. DO NOT
EXPECT MUCH IN THE WAY OF SEVERE ACTIVITY ALTHOUGH IF IT WERE TO
OCCUR THE MAIN THREAT WOULD BE DAMAGING WINDS. SKINNY CAPE PROFILES
DO NOT SUPPORT HAIL VERY WELL ALTHOUGH FREEZING LEVELS ARE LOWER
THAN IN PREVIOUS DAYS AT 13.5 KFT. MAXIMUM TEMPERATURES THIS
AFTERNOON WILL TOP OUT IN THE LOWER 80S.
TONIGHT HIGH RESOLUTION MODELS DO TRY TO CONTINUE OF WAVE OF
CONVECTION OFF THE MOUNTAINS BUT THIS SHOULD STRUGGLE TO SURVIVE
WITH LACK OF DAYTIME HEATING. THE BIGGER PROBLEM FOR THE OVERNIGHT
HOURS...ESPECIALLY IN THE EAST WILL BE AREAS OF FOG WHICH COULD
BEGIN JUST AFTER 9Z AND COULD REMAIN THROUGH SUNRISE. AN SPS OR
DENSE FOG ADVISORY WOULD NOT BE OUT OF THE QUESTION EAST OF I-95. IN
THE TRIAD THERE WILL BE LESS MOISTURE TO SUPPORT FOG DEVELOPMENT BUT
SOME VISIBILITY REDUCTIONS DURING THE OVERNIGHT HOURS ARE STILL
POSSIBLE. LOWS OVERNIGHT IN THE MID TO UPPER 60S.
FOR TUESDAY THE CHANCES FOR SEVERE WEATHER FOR TOMORROW AFTERNOON
WILL BE A BIT BETTER WITH MORE INSTABILITY AVAILABLE BUT IT WILL BE
CONFINED TO EASTERN PORTIONS OF THE CWA AND SHOULD STILL BE
ISOLATED. SHEAR WILL STILL BE PLENTIFUL AS THE JET CONTINUES TO MAKE
AN EXIT TO THE NORTHEAST. DURING THE AFTERNOON HOURS A 500 MB VORT
MAX SHOULD MAKE HEADWAY UP THE COAST BUT WHETHER OR NOT THIS FEATURE
PASSES CLOSE ENOUGH TO THE EASTERN PERIPHERY TO HELP SUPPORT
CONVECTION REMAINS TO BE SEEN. SURFACE HIGH PRESSURE TO THE
NORTHWEST WILL START TO WORK INTO THE AREA...POTENTIALLY CONFINING
CONVECTION EVEN FURTHER TO THE EAST DEPENDING ON PROGRESS. WHILE THE
UPPER LEVEL TROUGH WILL STILL BE IN PLACE IT WILL BEGIN TO LIFT OUT
AS THE UPPER JET CONTINUES UP THE EASTERN SEABOARD. MAX TEMPERATURES
TUESDAY WILL BE IN THE LOWER 80S WITH LOWS TUESDAY NIGHT IN THE MID
60S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 305 AM MONDAY...
TUESDAY...
ANOTHER... STRONGER UPPER LEVEL VORTICITY MAXIMUM AND
RESULTANT SURFACE WAVE IS FORECAST TO TRACK NE ACROSS SOUTH CAROLINA
AND EASTERN NORTH CAROLINA TUESDAY AFTERNOON AND EVENING. THE JET
STRUCTURE WILL BE FAVORABLE (RIGHT ENTRANCE REGION OF THE MID-UPPER
JET CENTERED FROM NC TO OFF THE NEW ENGLAND COAST) FOR THUNDERSTORM
ORGANIZATION. INTERESTINGLY... SEVERAL OF THE MODELS SUGGEST THAT WE
WILL HAVE MORE TIME FOR BREAKS IN THE OVERCAST AND SURFACE HEATING
BEFORE THE CONVECTION ARRIVES. IF SO... HIGHS IN THE LOWER TO MID
80S AND DEW POINTS WELL INTO THE 60S WOULD YIELD MLCAPES NEARING
1500 J/KG... ESPECIALLY SE OF THE TRIAD REGION. EVEN IN THE TRIAD...
IT SHOULD BECOME MODESTLY UNSTABLE... BUT IF HIGHS TO NOT REACH
80... CAPES WOULD REMAIN BELOW 1000 J/KG. THEREFORE... WE WILL
MENTION ISOLATED SEVERE (DAMAGING WIND THE MAIN THREAT) IN ALL BUT
THE NW TUESDAY AFTERNOON. MODELS GENERALLY FAVOR THE CENTRAL AND
EASTERN ZONES WITH THE HIGHEST QPF AS WELL (ALONG OR IN THE WARM
SECTOR OF THE EXPECTED POSITION OF THE NEARLY STATIONARY BOUNDARY.
WE WILL CARRY LOW STRATUS EARLY... SLIGHT CHANCE OF SHOWERS... THEN
MOSTLY CLOUDY NW TO PARTLY SUNNY EAST. SHOWERS AND THUNDERSTORMS
LIKELY IN THE AFTERNOON AND EVENING. HIGHS 80-85. QPF OF 0.25 TO
0.50 WITH LOCALLY 1+ INCH ESPECIALLY IN THE EAST.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...
RAINFALL CHANCES WILL BEGIN A SIGNIFICANT DOWNWARD TREND
TUESDAY NIGHT AND WEDNESDAY AS THE LAST IN A SERIES OF STRONGER
NORTHERN STREAM WAVES ROTATES THROUGH THE BASE OF THE UPPER TROUGH
AND ACROSS THE MID ATLANTIC STATES. THERE ARE SOME MODEL
DIFFERENCES REGARDING THE STRENGTHEN OF THE SHORTWAVE AND ASSOCIATED
SURFACE LOW THAT IS FORECAST TO DEVELOP ALONG THE STATIONARY FRONT
LIKELY LINGERING NEAR THE COAST. THE NAM IS THE STRONGEST OF THE
OPERATIONAL MODELS AND THE GFS IS THE WEAKEST. A COMPROMISE OF THE
TWO IS CLOSER TO THE ECMWF SOLUTION...WHICH SHOWS THE SURFACE
FRONT/WAVES OFFSHORE WEDNESDAY MORNING. THE SLOWER/WEAKER GFS WOULD
SUPPORT MORE CONVECTIVE POTENTIAL OVER THE COASTAL PLAIN
WEDNESDAY...SO WE WILL MAINTAIN A AT LEAST A SMALL CHANCE EAST OF
I-95 DURING THE AFTERNOON. WITH EITHER SOLUTION...THERE SHOULD BE
MORE BREAKS IN CLOUD COVER WESTERN NC..WHICH MAY LEAD TO AN A
TYPICAL MAX TEMP DISTRIBUTION...WITH THE HIGHER END OF THE FORECAST
MID 80S OVER THE WESTERN PIEDMONT. LOWS IN MID TO UPPER 80S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 305 AM MONDAY...
THE ANOMALOUSLY DEEP AND PERSISTENT UPPER TROUGH OVER THE EASTERN
HALF OF THE COUNTRY WILL HAVE WEAKENED SIGNIFICANTLY BY
THURSDAY...WITH A LESS DEFINED/AMPLIFIED UPPER LEVEL TROUGH TO
LINGER THROUGH THE WEEKEND. MODELS GENERALLY AGREE
ON SURFACE HIGH PRESSURE SETTLING OVER THE EAST COAST STATES AND
PERSISTING THROUGH THE PERIOD...WHICH SHOULD YIELD TEMPS RIGHT
AROUND NORMAL IN THE MID 80S FOR HIGH AND LOWS IN THE MID/UPPER
60S. THE GFS IS A BIT MORE ACTIVE THEN THE ECMWF REGARDING
CONVECTION BENEATH THE WEAK UPPER TROUGH EACH DAY...BUT WITH A DRIER
AND LESS UNSTABLE AIRMASS EXPECTED WITH THE SURFACE
HIGH...SHOWERS/STORMS SHOULD BE MAINLY ISOLATED AND TIED TO THE
AFTERNOON SEABREEZE AND DIFFERENTIAL HEATING ALONG THE HIGHER
TERRAIN.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 130 PM MONDAY...
24 HOUR TAF PERIOD: CEILINGS ARE BEGINNING TO BREAK THIS AFTERNOON
AS SITES RETURN TO VFR CONDITIONS. THIS TREND WILL CONTINUE OVER THE
NEXT SEVERAL HOURS. THE QUESTION FOR THIS AFTERNOON WILL BE WHETHER
IT BECOMES UNSTABLE ENOUGH TO PRODUCE SHOWERS AND THUNDERSTORMS. THE
MOST LIKELY AREA FOR THIS TO HAPPEN WOULD BE THE SOUTHEAST BUT KGSO
AND KINT MAY BE THREATENED LATER ON AS CONVECTION DEVELOPS OFF OF
THE MOUNTAINS AND THE FOOTHILLS. THE PROBLEM HERE WILL BE THE LOSS
OF DAYTIME HEATING BEFORE CONVECTION ARRIVES AT THE TERMINALS.
OTHERWISE THE PROBLEM OF THE DAY WILL BE 1/2 MILE VISIBILITIES AND
FOG OVERNIGHT. THIS WILL BE MORE PREVALENT FURTHER TO THE EAST AFTER
9Z UNTIL SUNRISE. FURTHER TO THE WEST VISIBILITIES DOWN TO 3 MILES
WILL BE MORE OF A CONCERN. CALM CONDITIONS OVERNIGHT WILL HELP
SUSTAIN FOG DEVELOPMENT. WINDS PICK UP TO 5 KNOTS AFTER SUNRISE AND
FOG SHOULD BURN OFF BY MID-MORNING ON TUESDAY. NO MENTION OF STORMS
IN THE TAF FOR TUESDAY AFTERNOON AT THIS TIME BUT THERE WILL BE A
POSSIBILITY OF SOME CONVECTION...MAINLY EAST OF I-95.
LONG TERM: FOG AND STRATUS WILL BE POSSIBLE ONCE AGAIN ON WEDNESDAY
MORNING. OTHERWISE AFTERNOON SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE IN THE EAST THROUGH THE END OF THE WEEK.A DRYING PATTERN
WILL HELP TO SUSTAIN VFR CONDITIONS THROUGH THE WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...ELLIS
SHORT TERM...BADGETT/SMITH
LONG TERM...SMITH
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
146 PM EDT MON AUG 20 2012
.SYNOPSIS...
A COLD FRONT WILL SLOWLY SLIDE EAST OF THE SOUTHERN APPALACHIAN
REGION ON TUESDAY REMAINING IN THE AREA THROUGH WEDNESDAY. ON
THURSDAY HIGH PRESSURE WILL BUILD OVER THE WESTERN CAROLINAS AND
NORTHEAST GEORGIA AS THE FRONT PUSHES OFF THE COAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 130 PM EDT...NO MAJOR CHANGE WERE MADE TO THE FCST. TEMPS AND
TD/S WERE TWEAKED ACROSS THE ERN ZONES TO ACCOUNT FOR THE PERSISTENT
CLOUD COVER.
AS OF 1030 AM EDT...MADE A FEW CHANGES FOR THE MORNING UPDATE. LOW
LEVEL CLOUD COVER IS HANGING TOUGH ACROSS THE ERN ZONES AND
ACCOUNTED FOR THIS IN THE SKY GRIDS. THE 13Z SFC ANALYSIS SHOWS THE
STATIONARY FRONT ACROSS THE MIDLANDS WITH A MESO LOW LOCATED ACROSS
ERN NC...WHICH REMAINS THE MAIN FOCUSING MECHANISM FOR PRECIP.
THUS...POPS HAVE BEEN TAKEN OUT OF THE ERN ZONES FOR LATE MORNING
AND EARLY AFTERNOON. EXPECT SCT GENERAL CONVECTION THIS
AFTERNOON...A FEW IN THE MTNS...BUT MOST ACTIVITY TO THE SOUTH AND
EAST. THE UPPER JET MAX CONTINUES TO SHIFT NE OF THE AREA...SO A
LESS DYNAMICAL SETUP IS IN STORE AND SBCAPE VALUES WILL BE LOW END.
DEEP BULK SHEAR WILL BE HIGH...BUT EFFECTIVE SHEAR LOW TO MODERATE.
SO...NOT ANTICIPATING ANY REAL CONCERNS WITH SVR CONVECTION THIS
AFTERNOON. MAX TEMPS WERE ADJ DOWN A DEGREE OR TWO ACROSS THE ERN
HALF OF THE CWFA TO ACCOUNT FOR THE OPAQUE CLOUD COVER.
AS OF 520 AM EDT...RAIN CONTINUES ACROSS THE I-77 CORRIDOR...THOUGH
THE BACK EDGE OF THE PCPN CONTINUES TO SLOWLY MOVE EAST. UPPED POPS
FOR A FEW MORE HOURS TO ACCOUNT FOR THE BACK EDGE OF THE FRONTAL
BAND PCPN. ALSO CUT BACK ON FOG A LITTLE OUT INTO THE PIEDMONT WHERE
MID LEVEL CLOUDS PROBABLY WON/T CLEAR UNTIL AFTER SUNRISE.
PREVIOUS DISCUSSION...
RAIN IS BECOMING MORE WIDESPREAD OVER THE SRN UPSTATE AND NC
PIEDMONT THOUGH THE AREA OF PCPN IS STILL EXHIBITING A GRADUAL PUSH
TO THE EAST. IT APPEARS THAT THE SHORT WAVE ERN TN...EVIDENT IN
DRYING IN THE WATER VAPOR IMAGERY...IS HELPING TO ENHANCE UPPER
DIVERGENCE IN THE ENTRANCE REGION OF THE JET. THE HRRR HAS PICKED UP
ON THIS AREA OF PCPN AND IS ALSO SHOWING A SLOW EASTWARD MOVEMENT.
THEREFORE...THE PCPN SHOULD GRADUALLY CLEAR THE EASTERN ZONES BY
SUNRISE. ACROSS THE MOUNTAINS AND FOOTHILLS AREAS OF DENSE FOG WILL
LIKELY DEVELOP AS THE UPPER LEVEL SUBSIDENCE PUSHES INTO THE WRN
ZONES. AGEOSTROPHIC FLOW ORIENTED FROM THE NW ON THE SUBSIDENCE SIDE
OF THE JET IS CONTRIBUTING TO SOME MIXING AND DRY AIR ADVECTION
ACROSS THE FRENCH BROAD VALLEY. I SUSPECT THIS WILL WEAKEN AS THE
WAVE PUSHES TO THE EAST AND FOG SHOULD SET UP EVEN IN THE LARGE
VALLEYS SOON.
LATER TODAY THE SFC FRONT...WHICH HAS NOW MOVED INTO THE SRN PART OF
THE UPSTATE...WILL LIFT BACK TO THE NORTH. THIS SHOULD RESULT IN
GOOD LLVL CONVERGENCE ROUGHLY ALONG THE I-85 CORRIDOR AND I SUSPECT
THAT SCT LATE AFTN AND EVENING TSTMS WILL DEVELOP IN THIS AREA.
CONVECTION MAY LAST A WAYS INTO THE OVERNIGHT PERIOD AS THE NAM
SHOWS IMPROVING LLVL CONVERGENCE THIS EVENING WITH THE FRONT
BECOMING MORE DEFINED. OVER THE MTNS LOWER DEWPOINT AIR BEHIND THE
BNDRY WILL RESULT IN A PLEASANTLY COOL NIGHT WITH LOWS FALLING INTO
THE LOWER TO MID 50S IN MANY LOCATIONS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 230 AM MONDAY...ON TUESDAY...THE MID LEVEL TROF AXIS IS
EXPECTED TO RUN ACROSS THE OHIO RIVER AND MISSISSIPPI RIVER VALLEYS
DURING THE AFTERNOON. THE GFS AND ECMWF INDICATES THAT THE REGION
EAST OF THE TROF WILL SEE AN IMPRESSIVE LATE SUMMER JET...WITH A
LONG BAND OF UPPER DIVERGENCE ALONG AND WEST OF THE ATLANTIC COAST.
HIGH TEMPERATURES IN THE MID 80S AND DEWPOINTS IN THE L60S SHOULD
YIELD WEAK TO MODERATE AFTERNOON INSTABILITY. THE COMBINATION OF THE
UPPER FORCING AND INSTABILITY SHOULD SUPPORT SCT
SHRA/TSRA...ESPECIALLY EAST OF I-85. CONVECTION SHOULD DISSIPATE
THROUGH THE EVENING HOURS...BUT ISOLATED COVERAGE COULD CONTINUE
ACROSS THE PIEDMONT INTO EARLY WED MORNING. LOW TEMPERATURES ARE
FORECAST TO RANGE FROM THE U50S ACROSS THE MTNS VALLEYS TO THE MID
60S EAST.
ON WEDNESDAY...THE H5 TROF AXIS WILL MOVE OVER THE SOUTHERN
APPALACHIAN REGION DURING THE AFTERNOON. A VORT MAX WITHIN THE TROF
AXIS WILL LIKELY RIPPLE OVER THE MTNS DURING THE LATE AFTERNOON.
HIGH TEMPERATURES MAY RANGE A DEGREE OR TWO WARMER THAN TUESDAY WITH
DEWPOINTS IN THE LOWER TO MID 60S. GFS CAPE VALUES SHOULD ARE
FORECAST TO RANGE AROUND 1000 J/KG. BASED ON WEAK DIURNAL
INSTABILITY AND THE APPROACH OF A WEAK MID LEVEL DISTURBANCE I WILL
FORECAST A DIURNAL SCHC ACROSS THE CWA...WITH CHC POPS ACROSS THE
HIGHEST ELEVATIONS. CONVECTION SHOULD COME TO AN END DURING THE LATE
EVENING. WEDNESDAY NIGHT IS FORECAST TO REMAIN DRY...CALM...AND MIN
TEMPS AROUND 3-5 DEGREES BELOW NORMAL.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 245 AM MONDAY...WEAK MID LEVEL RIDGING WILL BUILD OVER THE
REGION THURSDAY THROUGH SUNDAY. AT THE SFC...BROAD HIGH PRESSURE
CENTERED OVER THE MID ATLANTIC STATES WILL RIDGE SW ACROSS THE CWA
THROUGH THE PERIOD. TEMPERATURES EACH AFTERNOON IS EXPECTED TO RANGE
FROM NEAR 80 ACROSS THE MTNS VALLEYS TO THE MID 80S EAST. DEWPOINTS
WILL ALSO RANGE IN THE 60S EACH AFTERNOON...YIELDING WEAK TO
MODERATE INSTABILITY. DIURNAL ISO TO CHC CONVECTION IS EXPECTED EACH
DAY...WITH COVERAGE FAVORED OVER THE HIGH TERRAIN.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AT KCLT...LINGERING MVFR CIGS SHOULD CONTINUE TO BECOME MORE
SCATTERED WITHIN THE NEXT COUPLE HRS PER THE LATEST DRYING TRENDS ON
THE VIS. NO GREAT CONVECTIVE THREAT THIS AFTERNOON...SOME STORMS
WILL DEVELOP OFF TO THE WEST THIS AFTERNOON...BUT COVERAGE WILL BE
ISOL AND CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE A TEMPO. CROSS
SECTIONS HAVE LLVL MOISTURE BEING MAINTAINED OVERNIGHT AND MVFR OR
PERHAPS IFR STCU IS POSSIBLE BEFORE DAYBREAK. AN EARLIER LIFT OF
CIGS TO VFR IS EXPECTED TOMORROW MORNING...GENERALLY AROUND 15Z.
ELSEWHERE...NO SIGNFT FLIGHT RESTRICTIONS ARE IN STORE THROUGH THE
FIRST HALF OF THE TAF PERIOD. SOME ISOL STORMS MAY DRIFT OVER A
TERMINAL AND TEMPORARILY LOWER CIGS AND VSBYS...HOWEVER THE
COVERAGE THIS AFTERNOON WILL BE TOO LOW TO INCLUDE VCTS OR TEMPO
TSTMS. MORNING STCU SHOULD DEVELOP ACROSS MOST AREAS IN A STAGNANT
AIRMASS...SO CIGS LOWERING INTO THE MFVR...PERHAPS IFR RANGE AFT
MIDNIGHT IS POSSIBLE.
OUTLOOK...A WEAK STATIONARY BOUNDARY WILL LINGER ACROSS THE REGION
THROUGH THE EARLY WEEK. SFC LOWS MAY TRACK ALONG THE
FRONT...SUPPORTING PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH
TUESDAY. IN ADDITION...THE FORMATION OF LOW CLOUDS AND FOG IS
POSSIBLE EACH MORNING...ESPECIALLY NEAR AREAS OF RECENT RAINFALL.
CONDITIONS SHOULD IMPROVE WED AND THU.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...NED
NEAR TERM...MCAVOY/SBK
SHORT TERM...NED
LONG TERM...NED
AVIATION...SBK
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1233 PM CDT MON AUG 20 2012
.UPDATE...
UPDATE FOR 18Z AVIATION DISCUSSION.
&&
.PREV DISCUSSION... /ISSUED 1101 AM CDT MON AUG 20 2012/
DISCUSSION...
SKIES ARE SUNNY ACROSS THE MIDSOUTH THIS MORNING. DEWPOINTS ARE
MOSTLY IN THE 50S WITH TEMPS IN THE 70S. A MID LEVEL TROF WILL
SLOWLY PUSH ACROSS THE AREA TODAY. MOISTURE IS VERY LIMITED SO
JUST EXPECT SOME HIGH BASED CU THIS AFTERNOON THOUGH CANNOT RULE
OUT A SHOWER OR TWO. THE HRRR IS KICKING OUT SOME ISOLD SHOWERS
ACROSS WESTERN PARTS FOR THE MIDSOUTH THOUGH IT SEEMS A LITTLE
OVERDONE CONSIDERING THE DRY AIRMASS IN PLACE. ONGOING FORECAST
LOOKS GOOD WITH NO CHANGES NEEDED ATTM.
SJM
PREV DISCUSSION... /ISSUED 418 AM CDT MON AUG 20 2012/
UPPER LEVEL NORTHWESTERLY FLOW WILL GRADUALLY WEAKEN THROUGH THE
WEEK...AS A BROAD UPPER LEVEL HEIGHT RIDGE EXPANDS EASTWARD FROM
THE SOUTHERN PLAINS. THIS UPPER RIDGE WILL REMAIN CENTERED OVER
TEXAS...WITH SOME WEAKNESSES IN THE RIDGE DEPICTED BY THE GFS AND
ECMWF LATE IN THE WEEK. THE 00Z RUNS OF BOTH MODELS ARE HAVE MOVED
TOWARD A DRIER WEEKEND FOR THE MIDSOUTH... WITH SLIGHTLY STRONGER
UPPER RIDGING...AND A WEAKER SHEAR AXIS PLACED FURTHER WEST OVER
MO/AR/LA. MODEST LOW LEVEL MOISTURE RETURN MAY BE INSUFFICIENT TO
OVERCOME WARMING MIDLEVEL TEMPS...AND IT APPEARS CONVECTIVE
INHIBITION MAY BE STRONGER THIS WEEKEND THAN PREVIOUSLY
ANTICIPATED.
IN THE INTERIM... A DRY MIDCONTINENTAL AIRMASS WILL BE OVERSPREAD
BY MIDLEVEL CLOUDS TODAY. THE DEPARTURE OF THESE CLOUDS WILL PLAY
A LARGE ROLE ON SURFACE TEMPS. CLOUDS SHOULD BE LESS PREVALENT
ON TUESDAY AND WEDNESDAY...AS THE MAIN MIDLEVEL MOISTURE FETCH
SHIFTS EASTWARD TO THE CAROLINAS...AHEAD OF A PROGRESSIVE AND
WEAKENING UPPER LEVEL TROF.
GFS MOS TEMPS GENERALLY ON TARGET...BUT HAVE BUMPED MIDWEEK TEMPS
A DEGREE OR TWO...GIVEN THE DRY AIRMASS AND SUNNY SKIES.
PWB
&&
.AVIATION...
18Z TAF CYCLE
VFR CONDITIONS SHOULD CONTINUE FOR THE MAJORITY OF THE FORECAST
CYCLE. SCATTERED CUMULUS WILL DEVELOP THIS AFTERNOON AND DIE OFF
BY THE EVENING. SOME MODELS ARE INDICATING SOME SHOWERS DEVELOPING
THIS AFTERNOON...BUT CONFIDENCE WAS NOT HIGH ENOUGH TO PLACE THIS
IN THE TAF AT THIS TIME. NORTHEAST WINDS WILL BECOME LIGHT THIS
EVENING...POSSIBLY GOING CALM AT ALL SITES. THERE WILL BE A
CHANCE OF FOG AT KMKL AND KTUP DUE TO CLEAR SKIES AND LIGHT WINDS.
DENSE FOG IS NOT EXPECTED DUE TO THE ONGOING DROUGHT AND SOMEWHAT
DRIER AIRMASS. NORTHEAST WINDS WILL PICK UP TO 5-6 KTS AGAIN BY
LATE TOMORROW MORNING.
RRH
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 89 64 89 65 / 10 10 10 0
MKL 86 57 89 58 / 10 10 10 0
JBR 85 59 89 59 / 10 10 0 0
TUP 85 61 88 61 / 10 10 10 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
356 PM EDT MON AUG 20 2012
.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN JUST TO OUR SOUTH THROUGH TUESDAY.
MEANWHILE...A COUPLE OF WEAK UPPER LEVEL DISTURBANCES WILL PASS
ACROSS OUR REGION FROM THE WEST ON MONDAY AND AGAIN ON TUESDAY.
THIS WILL HELP REDEVELOP SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS OVER OUR REGION ON BOTH DAYS. BY MID WEEK THE FRONT
WILL MOVE OFF THE ATLANTIC COAST...ALLOWING HIGH PRESSURE TO BUILD
INTO THE REGION FROM THE WEST AND REDUCING THE CHANCES FOR SHOWERS
AND STORMS.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 230 PM EDT MONDAY...
SHORTWAVE WILL ROTATE AROUND THE UPPER TROUGH ACROSS OUR REGION THIS
AFTERNOON INTO TONIGHT. THIS WILL RESULT IN SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS. SOME OF THE STRONGER STORM MAY CONTAIN GUSTY
WINDS AND HEAVY DOWNPOURS. THE FRONTAL BOUNDARY ACROSS THE SOUTHEAST
U.S. WILL REMAIN TO OUR SOUTH TONIGHT INTO TUESDAY. HRRR AND
WRFARW-RNK LOOKED REASONABLE WITH TIMING AND PLACEMENT OF STORMS.
CONVECTION THIS AFTERNOON WILL SLOWLY DISSIPATE WITH THE LOSS OF
SOLAR HEATING AND PASSAGE OF THE SHORTWAVE. WITH LIGHT WINDS AND LOW
LEVEL MOISTURE ADDED THE MENTION OF FOG TO THE ISC GRIDS TONIGHT
INTO TUESDAY MORNING. LEANED TOWARDS THE ADJMETBC FOR LOW
TEMPERATURES WITH READINGS FROM THE LOWER 50S IN THE MOUNTAINS TO
THE MID 60S IN THE SOUTHEAST.
THE LARGE UPPER LEVEL TROUGH IN THE EAST WILL CONTINUE TUESDAY.
ANOTHER SHORTWAVE WILL DROP SOUTHEAST OUT OF THE OHIO VALLEY ACROSS
OUR REGION. IN THE LOWER LEVELS...WEAK HIGH PRESSURE SITUATED ACROSS
THE LOWER GREAT LAKES SLIDES INTO THE APPALACHIANS...WHILE THE
NEARLY STATIONARY FRONT WILL REMAIN ALONG THE COASTAL SOUTHEAST.
SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP TUESDAY AFTERNOON
INTO TUESDAY NIGHT. RAINFALL WILL DIMINISH DURING THE EVENING AS
DAYTIME HEATING ENDS. PLAYED HIGH TEMPERATURES TUESDAY FROM THE
LOWER 70S IN THE MOUNTAINS TO THE LOWER 80S IN THE PIEDMONTS.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 330 PM EDT MONDAY...
RESIDENT UPPER TROUGH IS FORECAST TO FLATTEN MID WEEK WITH RETURN
OF CLOSER TO NORMAL TEMPS. CAN`T RULE OUT ISOLD TO WDLY SCATTERED
POP-UP SHRA/TSRA DURING THE PEAK HEATING HOURS EACH DAY...BUT POPS
PRETTY LOW...20 PERCENT OR LESS...AND FAVORING MAINLY DRY
CONDITIONS. AS THE AIRMASS WARMS AND DRIES...SHOULD SEE A GREATER
DIURNAL TEMPERATURE SPREAD WITH HIGHS IN THE 80S AND LOWS IN THE
50S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 400 PM EDT MONDAY...
WITH FLOW DEAMPLIFIED...NO BIG EXTREMES ANTICIPATED IN THE LONG
TERM. HIGH PRESSURE SHOULD COVER MUCH OF THE ERN CONUS WITH LAZY
LOW LEVEL FLOW. UPPER LEVEL DISTURBANCES WILL BE BURIED WITHIN THE
FLOW...BUT CAN`T ADD ANY GREAT DETAIL TO THE SENSIBLE WEATHER DUE
TO TIMING UNCERTAINTIES. TEMPERATURES SHOULD NOT BE TOO FAR FROM
CLIMO.
AS WE TRANSITION INTO THE WEEK OF AUG 26-31...THE TROPICS WILL
PROBABLY BECOME MORE OF INTEREST. HPC HAS ADDED A TROPIC LOW VCNTY
OF FLORIDA BY DAY 7 PER COORDINATION WITH THE HURRICANE
CENTER...REPRESENTING POSSIBLE TRACK OF AL94.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
AS OF 200 PM EDT MONDAY...
AN UPPER AIR DISTURBANCE WILL MOVE EAST ACROSS THE REGION THIS
AFTERNOON INTO TONIGHT. THIS WILL PRODUCE SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING. THE
SHALLOW INSTABILITY SHOULD LIMIT THUNDERSTORM COVERAGE...BECAUSE
OF THIS WILL NOT MENTION THUNDERSTORMS AT THE TAF LOCATIONS. LWB
AND ROA HAVE THE BEST CHANCE FOR CONVECTION...BUT ISOLATED STORMS
ARE POSSIBLE AT THE OTHER AIRPORTS. GUSTY WINDS AND SMALL HAIL ARE
POSSIBLE WITH THE STRONGER STORMS.
WINDS BASICALLY LIGHT AND VARIABLE...BUT WITH MIXING THIS AFTERNOON
WILL TEND TO HAVE A WESTERLY COMPONENT...ESPECIALLY IN THE WEST.
EAST A LITTLE TRICKIER...WITH POSSIBLE NORTHEASTERLY COMPONENT
INITIALLY...THEN MAYBE WEST LATE. STILL 5KT OR LESS.
WITH PARTIAL CLEARING AGAIN TONIGHT PRIMARILY IN THE WEST
OVERNIGHT...PATCHY FOG WITH IFR CONDITIONS AGAIN POSSIBLE AT LWB
ESPECIALLY...BCB AND BLF MORE LIKELY MVFR OR ONLY VERY BRIEF IFR.
VFR MOST LIKELY EAST...UNLESS HEAVIER SHOWERS IMPACT A PARTICULAR
AIRPORT AFT/EVE...THEN MVFR TO IFR FOG MAY BE POSSIBLE TOWARD
MORNING. INCLUDED BRIEF PERIOD OF MVFR FOG AT LYH FOR NOW. MUCH
DEPENDS ON DEGREE OF CLEARING...WHICH IS LESS LIKELY AT DAN.
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE AGAIN ON
TUESDAY...WITH ISOLATED AND BRIEF MVFR/IFR CONDITIONS ARE
POSSIBLE. BY WEDNESDAY THE COLD FRONT CONTINUES TO MOVE FURTHER TO
OUR EAST. HIGH PRESSURE WILL THEN BUILD IN FOR THE REMAINDER OF
THE PERIOD...WITH MAINLY VFR/MVFR CONDITIONS EXPECTED AND VERY
LITTLE OR NOW CHANCE OF SHOWERS OR STORMS DEVELOPING.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...KK
NEAR TERM...KK
SHORT TERM...PM
LONG TERM...PM
AVIATION...KK/SK
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1146 AM CDT MON AUG 20 2012
.UPDATE...
MAIN CONCERN TODAY ARE WX/POPS...THOUGH A FEW OTHER CHANGES WERE
MADE TO TEMPS AND SKY COVER TO ADJUST FOR LATEST TRENDS. A
SOMEWHAT SIMILAR SYNOPTIC SITUATION COMPARED TO YESTERDAY...WITH
THE SAME COLD-CORE SYSTEM OVER EASTERN JAMES BAY WITH A LARGE 500
HPA TROUGH OVER THE WESTERN GREAT LAKE REGION. SOUTH CENTRAL
WISCONSIN CURRENTLY SITS ON THE PERIPHERY OF A SFC HIGH OVER THE
UPPER MISSISSIPPI VALLEY...THAT WILL BE TRACKING EAST TODAY. A S/W
TROUGH IS EVIDENT FROM THE WV LOOP OVER WEST CENTRAL WISCONSIN AND
IS TRACKING SSE.
TODAY EXPECTING ISOLATED AND SCATTERED SHOWERS WITH ISOLATED
THUNDER IN THE EAST HALF. EAST HALF WILL HAVE ONSHORE FLOW WITH
LAKE BREEZE BOUNDARY THIS AFTERNOON...HIGHER DEWPOINTS PROVIDING
SOME INSTABILITY IN CONJUNCTION WITH THE INCOMING S/W TROUGH IN
THEIR FAVOR. NON SUPERCELL TORNADO PARAMETER VALUES OF 1 TO 2
LINGER OVER LAKE BREEZE BOUNDARY THIS AFTERNOON...SO WILL HAVE TO
WATCH CELLS THAT DEVELOP THERE FOR ROTATION. ALSO WILL HAVE TO
WATCH FOR HAIL AND GUSTY WINDS GIVEN MEAN LAYER CAPES TO AROUND
500 J/KG WITH LOW FREEZING LEVELS.
TEMPS WERE NOT CHANGED MUCH...HIGHS WERE INCREASED INLAND OUT WEST
BY TWO DEGREES OR SO. 925 HPA TEMPS NEAR 19 C THAT CORRESPOND TO
AROUND 78 F...AND WITH ADEQUATE MIXING AND FEW-SCT SKIES...SHOULD
BE REALIZED. SKIES WERE BUMPED A BIT AS WELL FOR DIURNAL CU...WITH
MORE IN THE EASTERN HALF OF THE CWA...WHERE THERE WILL BE HIGHER
DEWPOINTS.
&&
.AVIATION/18Z TAFS/...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED TO
DEVELOP ACROSS THE EASTERN TAF SITES...NEAR THE LAKE BREEZE
BOUNDARY. WILL USE VICINITY SHOWER/THUNDERSTORM WORDING FOR NOW IN
TAFS UNTIL BETTER TRENDS ARE SEEN WITH AREAL COVERAGE THIS
AFTERNOON. MVFR VISIBILITIES ARE POSSIBLE IN ANY STORMS...BUT WILL
LEAVE OUT MENTION FOR NOW.
OTHERWISE...EXPECT SCATTERED TO BROKEN CUMULUS CLOUDS TO LINGER
THROUGH THE AFTERNOON ACROSS TAF SITES. LIGHT EAST WINDS ARE
EXPECTED AT MILWAUKEE AND KENOSHA EARLY THIS AFTERNOON...SPREADING
TO WAUKESHA BY MID TO LATE AFTERNOON. LIGHT AND VARIABLE WINDS ARE
EXPECTED AT MADISON.
SHOWERS/STORMS SHOULD DISSIPATE BY SUNSET ACROSS TAF SITES...WITH
SKIES CLEARING OUT DURING THE EVENING. HIGH PRESSURE BRINGING
LIGHT WINDS AND CLEAR SKIES LATER TONIGHT...WITH MVFR/IFR FOG
EXPECTED ONCE AGAIN AT MADISON AND KENOSHA...MAINLY VFR AT
WAUKESHA AND MILWAUKEE. FEW TO SCATTERED DIURNAL CUMULUS DEVELOPS
BY TUESDAY AFTERNOON...WITH LIGHT SOUTHEAST WINDS AT EASTERN TAF
SITES.
&&
.MARINE...
WILL REMOVE MENTION OF WATERSPOUTS FROM THE HAZARDOUS WEATHER
OUTLOOK...AS CONVECTIVE CLOUD DEPTHS ON NAM FORECAST SOUNDINGS AT
MILWAUKEE AND THE SOUTH MID LAKE MICHIGAN BUOY LOOKS TOO SMALL TO
SUPPORT WATERSPOUT DEVELOPMENT. SWI INDEX ALSO FAVORING THE FAR
SOUTHERN END OF LAKE MICHIGAN FOR DEVELOPMENT...WITH NON SUPERCELL
TORNADO PARAMETER VALUES REMAINING OVER LAKE BREEZE BOUNDARY AND
NOT OVER THE WATER.
STILL...SHOULD SEE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
FROM TIME TO TIME THIS AFTERNOON ACROSS THE NEARSHORE WATERS.
&&
.PREV DISCUSSION... /ISSUED 325 AM CDT MON AUG 20 2012/
SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM TO HIGH.
VALLEY FOG DEVELOP EARLY THIS MORNING WITH LIGHT WINDS AND CLEAR
SKIES...ESPECIALLY IN AREAS THAT RECEIVED PRECIPITATION. DENSE FOG
EXPECTED IN THE WISCONSIN RIVER VALLEY.
ISOLATED SHOWERS ARE EXPECTED MONDAY AFTERNOON IN THE EASTERN
COUNTIES. ONSHORE WINDS WITH HIGHER DEWPOINTS BRING WEAK INSTABILITY
HERE...AND COMBINE WITH APPROACHING SHORTWAVE TROUGH AND COLD MID
LEVELS TO BRING MEDIUM. ZERO TO 1 KM CAPE VALUES AROUND 4500 J/KG
OVER PORTIONS OF SOUTHEAST WISCONSIN.
4 KM HRRR DEVELOP AN AREA OF SHOWERS/THUNDERSTORMS LATE MORNING AND
AFTERNOON OVER THE LAKE SHORE AREA THAT PUSHES INLAND WITH LAKE
BREEZE. NON SUPERCELL INDEX VALUES RISE TO AROUND 2 TO 3...BUT
FORECAST SOUNDINGS HAVE ENOUGH MID LEVEL DRY AIR WITH LAPSE RATES
AROUND 8.8 C/KM AT 850 MB. SURFACE CONVERGENCE IS VERY WEAK AND 700
MB UPWARD MOTION IS WEAK.
EXPECT SOME PATCHY FOG AGAIN LATE TONIGHT...ESPECIALLY IN THE
WISCONSIN RIVER VALLEY.
TUESDAY AND TUESDAY NIGHT...FORECAST CONFIDENCE IS HIGH.
BEAUTIFUL DAY IN STORE FOR TUESDAY. HIGH PRESSURE WILL GRADUALLY
SHIFT EASTWARD. SUBSIDENCE BEHIND DEPARTING UPPER TROUGH WILL ALLOW
FOR ONLY A FEW CUMULUS CLOUDS IN THE AFTERNOON. LAKE BREEZE EXPECTED
WITH THE WEAK SURFACE GRADIENT. 925MB TEMPS WILL BE INCREASING
TOWARD 20C...YIELDING MAX TEMPS AROUND 80F.
WEDNESDAY THROUGH THURSDAY...FORECAST CONFIDENCE IS MEDIUM TO HIGH.
WEDNESDAY LOOKS LIKE IT WILL BE ANOTHER NICE DAY. THERE COULD BE
SOME HIGH-BASED SHOWERS THAT MAY OR MAY NOT REACH THE GROUND
WEDNESDAY NIGHT. THEN THURSDAY LOOKS LIKE IT WILL BE QUITE WARM IN
THE WARM SECTOR AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM.
THE NOSE OF THE LOW LEVEL JET IS FORECAST TO BE IN SOUTHEAST MN ON
MOST MODELS...EXCEPT THE NAM REACHES INTO FAR WESTERN WI BY WED
AFTERNOON. THE NAM AND GFS ARE MOST ROBUST WITH SHOWER POTENTIAL
OVER SOUTHERN WI WED NIGHT WITH THE WARM AIR ADVECTION AND A WEAK
SHORTWAVE...AND THE NHEM CANADIAN MODEL EVEN SHOWS LIGHT QPF IN THE
AREA...BUT THE ECMWF KEEPS IT DRY. FOR NOW...CONTINUED WITH THE DRY
FORECAST FOR WED AND WED NIGHT.
BY THURSDAY THE LOW LEVEL JET PUSHES INTO NORTHERN MN AND NORTHERN
WI...FOCUSING ANY WARM AIR ADVECTION CONVECTION WELL TO THE NORTH OF
OUR FORECAST AREA. THEREFORE...CONTINUED WITH THE DRY FORECAST.
THE WARMEST AIR IS EXPECTED TO PUSH INTO SOUTHERN WI BY THU
AFTERNOON...WITH 925MB TEMPS REACHING 25 TO 26C ON THE ECMWF. THE
NAM SHOWS CHARACTERISTICALLY HIGHER 925MB TEMPS SO IGNORED FOR NOW.
BUMPED UP THE MAX TEMPS FOR WED AND THU...WITH THU LIKELY REACHING
THE UPPER 80S TO POSSIBLY 90.
LONG TERM...
THURSDAY NIGHT THROUGH MONDAY...FORECAST CONFIDENCE IS LOW.
A 500MB TROUGH WILL SWING ACROSS THE UPPER MIDWEST EARLY IN THE
WEEKEND. THE GFS IS FASTEST WITH BRINGING SHOWERS AND THUNDERSTORMS
WITH A COLD FRONT INTO SOUTHERN WI THU NIGHT...WITH THE ECMWF MUCH
SLOWER. IN GENERAL...THIS FRONT WOULD BRING A ROUND OF TSTORMS
ACROSS SOUTHERN WI SOMETIME BETWEEN LATE THU NIGHT AND FRI
NIGHT...OR NOT AT ALL ACCORDING TO THE CANADIAN MODEL.
THE MAJOR UNCERTAINTY WILL BE PRECIP CHANCES FOLLOWING THAT INITIAL
FRONT...WHICH WILL DEPEND ON HOW THE MODELS HANDLE THE TIME BETWEEN
THE AFOREMENTIONED UPPER TROUGH AND THE NEXT UPPER TROUGH MOVING
THROUGH THE REGION SUNDAY THROUGH MONDAY. THE GFS MOVES A STRONG
SHORTWAVE INTO SOUTHERN WI FROM THE SOUTH SAT NIGHT AND THE ECMWF
AND CANADIAN MODELS JUST WAIT FOR THE SECOND TROUGH TO MOVE THROUGH
TO GENERATE MORE STORMS.
BOTTOM LINE IS THERE WILL BE TWO OR MAYBE 3 ROUNDS OF SHOWERS AND
THUNDERSTORMS BETWEEN LATE THU NIGHT AND MONDAY AFTERNOON BUT WE
JUST DO NOT KNOW WHEN.
AVIATION/12Z TAFS/...
LIGHT WINDS AND MOSTLY CLEAR SKIES SHOULD ALLOW FOR IFR/PATCHY LIFR
FOG POSSIBILITIES MAINLY IN LOW AREAS THAT RECEIVED PRECIPITATION
YESTERDAY. ALSO EXPECT LIFR FOG IN THE WISCONSIN RIVER VALLEY.
MORE SCATTERED TO BROKEN DIURNAL CUMULUS CLOUDS ARE EXPECTED TO
DEVELOP MONDAY AFTERNOON WITH CLOUD BASES AROUND 4-5 THSD FT.
ALSO EXPECT SCATTERED SHOWERS MAINLY OVER SOUTHEAST WISCONSIN BY
AROUND NOON AND THROUGH THE AFTERNOON. MVFR CIGS/IFR VSBYS IN THE
HEAVER SHOWERS AND THUNDERSTORMS. DRIER AIR OVER SOUTH CENTRAL AND
NORTHWEST PORTIONS OF SOUTHEAST WISCONSIN WITH LESS OF A SHOWER
POSSIBILITY.
SIMILAR FOG SITUATION FOR LATE TONIGHT.
MARINE...
4 KM HRRR AND LOCAL WRF HAS LOW LEVEL CYCLONIC CIRCULATION OVER FAR
SOUTHERN LAKE MICHIGAN. A FEW SHOWERS OVER THE ILLINOIS WATERS.
THEREFORE THREAT OF WATERSPOUTS LOW OVER OUR FORECAST AREA. HOWEVER
MODELS DEVELOP AN AREA OF SHOWERS/THUNDERSTORMS LATE MORNING AND
AFTERNOON OVER THE LAKE SHORE AREA THAT PUSHES INLAND WITH LAKE
BREEZE. ANY WATERSPOUT THREAT WOULD LIKELY OCCUR AS THESE SHOWERS
FORM.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...ET/WOOD
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
TUESDAY THROUGH SUNDAY...MRC