Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/22/12
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 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 MIAMI FL
1040 PM EDT TUE AUG 21 2012
.UPDATE...INCREASED POPS AREA WIDE FOR TONIGHT...ADDDING ISOLATED
TSTORMS POTENTIAL TO THE EAST COAST AND SCATTERED ACTIVITY FOR THE
INTERIOR AND GULF COAST BASED ON LATEST RADAR TRENDS OF ACTIVITY
MOVING IN FROM THE GULF AND CONVECTION AGAIN MOVING OFF OF CUBA
WHICH COULD IMPACT EASTERN AREAS OVERNIGHT. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 806 PM EDT TUE AUG 21 2012/
AVIATION...
LINGERING SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE ACROSS THE
REGION THIS EVENING. THE EAST COAST TERMINALS DO NOT HAVE ANY
THUNDERSTORMS IN THE VICINITY ALTHOUGH TERMINAL KPBI CURRENTLY HAS
LIGHT SHOWERS. MAINLY VFR CONDITIONS EXPECTED FOR THE EAST COAST
TERMINALS THIS EVENING ALTHOUGH KPBI COULD BRIEFLY HAVE SUB-VFR
CONDITIONS WITH ANY MODERATE SHOWERS OVER THE NEXT HOUR OR SO.
TERMINAL KAPF WAS ASSIGNED VCTS BUT SO FAR THUNDERSTORMS ARE NEAR
FT. MYERS AND ADJACENT GULF WATERS. IT IS POSSIBLE HOWEVER SOME
THUNDERSTORMS COULD MOVE ACROSS THE GULF WATERS AND AFFECT KAPF THIS
EVENING WITH SUB-VFR CONDITIONS IF THEY OCCUR AND WILL AMEND IF
NECESSARY.
60
PREV DISCUSSION... /ISSUED 209 PM EDT TUE AUG 21 2012/
DISCUSSION...
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS
THE INTERIOR AND PUSH TOWARDS THE NORTHEAST SECTIONS OF THE CWA THIS
AFTERNOON AND INTO THE EVENING UNDER THE SOUTHWEST FLOW ALOFT. A
FEW STORMS COULD BE STRONG...WITH THE MAIN THREAT BEING STRONG
WINDS OF 40 TO 50 MPH. THE HRRR IS SHOWING THAT A LINE OF STORMS
MAY MOVE ACROSS THE EASTERN GULF AND INTO CENTRAL FLORIDA...WITH
THE TAIL END OF THIS LINE OF SHOWERS AND THUNDERSTORMS POSSIBLY
MOVING INTO THE LOCAL GULF WATERS AND PORTIONS OF THE NORTHWEST
AFTER 00Z. THIS IS CONSISTENT WITH THE 12Z GFS SHOWING A PIECE OF
ENERGY ROTATING AROUND THE BASE OF THE TROUGH AND ACROSS CENTRAL
FLORIDA OVERNIGHT. SO WILL KEEP 20-30 POPS FOR THIS REGION.
THE UPPER TROUGH ALONG THE EASTERN SEABOARD WILL BEGIN TO FILL AND
LIFT TO THE NORTHEAST TONIGHT AND WEDNESDAY...BUT A WEAKNESS WILL
REMAIN OVER THE GULF AND THE WESTERN ATLANTIC THROUGH THE WEEKEND.
AT THE SURFACE...THE QUASI-STATIONARY FRONT OVER NORTH FLORIDA
WILL SLOWLY DRIFT SOUTHWARD TONIGHT INTO WEDNESDAY AND THEN BEGIN
TO WASH OUT AND DRIFT NORTHWARD INTO THURSDAY. THE SUBTROPICAL
RIDGE OVER THE WESTERN ATLANTIC WILL MOVE NORTHWARD AND THE DRY
AIR AND HAZE OVER THE BAHAMAS IS EXPECTED TO PUSH INTO SOUTH
FLORIDA ON WEDNESDAY AND THURSDAY. IN ADDITION...THE LOW/MID LEVEL
FLOW WILL SHIFT FROM THE SOUTHWEST TO THE EAST AND SOUTHEAST BY
THURSDAY.
WITH PWATS FALLING TO AROUND 1.5 INCHES ON WEDNESDAY ALONG THE
SOUTHEAST COAST...ONLY MINIMAL RAIN CHANCES ARE EXPECTED.
STEERING FLOW WILL PUSH STORMS SLOWLY TO THE NORTH ON WEDNESDAY.
HIGHER MOISTURE WILL ALSO LINGER AROUND THE LAKE ON WEDNESDAY...SO
THERE WILL STILL BE A CHANCE OF STORMS FOR THE LAKE OKEECHOBEE
REGION. MODEL SOUNDINGS ARE SHOWING RELATIVELY STEEP LAPSE RATES
ABOVE THE INVERSION AND STRONG STORMS AND POSSIBLY AN ISOLATED
SEVERE STORM CANNOT BE RULED OUT ON WEDNESDAY. HEAT INDICES WILL
BE THE TYPICAL 100-108F FOR THIS TIME OF YEAR...WITH THE HIGHEST
READINGS ACROSS THE INTERIOR.
EVEN DRIER AIR IS EXPECTED TO MOVE INTO THE REGION ON
THURSDAY...WITH PWATS ACROSS THE REGION DROPPING TO 1.3-1.6 INCHES.
WITH THE FLOW SHIFTING TO THE EAST AND SOUTHEAST...EXPECT THE EAST
COAST TO MAINLY STAY DRY...WITH ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS THE INTERIOR AND TOWARDS THE GULF COAST.
FOR FRIDAY INTO SATURDAY...THE PRESSURE GRADIENT MAY BEGIN TO
TIGHTEN AS TROPICAL DEPRESSION NINE MOVES NEAR HAITI AND EASTERN
CUBA. SO SOMEWHAT BREEZIER EASTERLY FLOW COULD BEGIN ON FRIDAY AND
SATURDAY WITH AN INCREASE IN LOW LEVEL MOISTURE AND RAIN CHANCES.
IT IS STILL TOO EARLY TO DETERMINE THE IMPACTS OF TROPICAL
DEPRESSION NINE ON SOUTH FLORIDA OR THE SURROUNDING MARINE AREAS IN
THE LONG TERM. HOWEVER...THERE IS INCREASING POTENTIAL THAT SOUTH
FLORIDA AND/OR THE SURROUNDING MARINE AREAS COULD BE IMPACTED LATE
THIS WEEKEND INTO EARLY NEXT WEEK. SO NOW IS A GOOD TIME TO
REVIEW INDIVIDUAL TROPICAL CYCLONE PREPAREDNESS PLANS. FOR THE
LATEST INFORMATION REGARDING TROPICAL DEPRESSION NINE...CONTINUE
TO MONITOR THE LATEST FORECASTS FROM THE NATIONAL HURRICANE
CENTER.
AVIATION...
A FEW THUNDERSTORMS COULD DEVELOP THIS AFTERNOON
MAINLY TOWARD KPBI AND KFXE, BUT EXPECT TO HAVE ACTIVITY CLOSE
ENOUGH TO THE REST OF THE ERN TERMINALS TO BE WORTH MENTIONING
VCTS IN TAFS. WL EXPECT ANY SHWR/TSTM TO REMAIN WELL AWAY FROM
KAPF AND NO AFFECT OPERATIONS. EVENING ACTIVITY SHOULD TAPER OFF
BY 00Z TONIGHT. SFC SHOULD REMAIN MOSTLY SE, ALTHOUGH BECOMING
LIGHT AND VARIABLE AFTER 00Z AND INCREASING AGAIN TO AROUND 8-10
KTS AFTER 13Z WEDNESDAY.
MARINE...
A RIDGE OF HIGH PRESSURE WILL BE LOCATED OVER THE SOUTH FLORIDA
WATERS THROUGH THE MIDDLE OF THE WEEK BEFORE SHIFTING NORTH DURING
THE LATTER PART OF THE WEEK. THIS WILL LEAD TO WINDS OUT OF THE
SOUTH BECOMING EASTERLY LATE IN THE WEEK. THE PRESSURE GRADIENT IS
EXPECTED TO INCREASE FRIDAY AND SATURDAY AS TROPICAL DEPRESSION
NINE MOVES NEAR HAITI AND EASTERN CUBA. THE FORECAST FOR LATE THIS
WEEKEND BECOMES HIGHLY DEPENDENT ON THE EVOLUTION THIS TROPICAL
CYCLONE. THE FORECAST TRACK OF THIS POTENTIAL SYSTEM IS IN THE
GENERAL DIRECTION OF THE REGIONAL WATERS AND SHOULD BE CLOSELY
MONITORED BY ALL MARINE INTERESTS OVER THE COMING DAYS.
FIRE WEATHER...
SOUTH TO SOUTHWEST WINDS WILL BE OVER SOUTH FLORIDA AGAIN ON
WEDNESDAY AS A HIGH PRESSURE RIDGE PERSISTS JUST SOUTH OF THE
AREA OVER THE KEYS AND FLORIDA STRAITS. ISOLATED TO SCATTERED
THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THE AFTERNOON ON
WEDNESDAY BUT AFFECTING MAINLY THE INTERIOR AND THE LAKE
OKEECHOBEE REGION AS THE ACTIVITY WILL MOVE TO THE NORTHEAST. EAST
AND WEST COAST SEA BREEZES ARE EXPECTED TO DEVELOP LATE THIS
MORNING AND CONTINUE INTO THIS AFTERNOON ON WEDNESDAY. FLOW WILL
BECOME MORE EASTERLY ON THURSDAY AND STRENGTHEN FRIDAY INTO THE
WEEKEND AS THE PRESSURE GRADIENT INCREASES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 91 78 89 / 20 20 10 10
FORT LAUDERDALE 80 91 80 91 / 20 20 10 10
MIAMI 79 92 79 91 / 20 10 10 10
NAPLES 77 93 77 93 / 50 30 20 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
806 PM EDT TUE AUG 21 2012
.AVIATION...
LINGERING SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE ACROSS THE
REGION THIS EVENING. THE EAST COAST TERMINALS DO NOT HAVE ANY
THUNDERSTORMS IN THE VICINITY ALTHOUGH TERMINAL KPBI CURRENTLY HAS
LIGHT SHOWERS. MAINLY VFR CONDITIONS EXPECTED FOR THE EAST COAST
TERMINALS THIS EVENING ALTHOUGH KPBI COULD BRIEFLY HAVE SUB-VFR
CONDITIONS WITH ANY MODERATE SHOWERS OVER THE NEXT HOUR OR SO.
TERMINAL KAPF WAS ASSIGNED VCTS BUT SO FAR THUNDERSTORMS ARE NEAR
FT. MYERS AND ADJACENT GULF WATERS. IT IS POSSIBLE HOWEVER SOME
THUNDERSTORMS COULD MOVE ACROSS THE GULF WATERS AND AFFECT KAPF THIS
EVENING WITH SUB-VFR CONDITIONS IF THEY OCCUR AND WILL AMEND IF
NECESSARY.
60
&&
.PREV DISCUSSION... /ISSUED 209 PM EDT TUE AUG 21 2012/
DISCUSSION...
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS
THE INTERIOR AND PUSH TOWARDS THE NORTHEAST SECTIONS OF THE CWA THIS
AFTERNOON AND INTO THE EVENING UNDER THE SOUTHWEST FLOW ALOFT. A
FEW STORMS COULD BE STRONG...WITH THE MAIN THREAT BEING STRONG
WINDS OF 40 TO 50 MPH. THE HRRR IS SHOWING THAT A LINE OF STORMS
MAY MOVE ACROSS THE EASTERN GULF AND INTO CENTRAL FLORIDA...WITH
THE TAIL END OF THIS LINE OF SHOWERS AND THUNDERSTORMS POSSIBLY
MOVING INTO THE LOCAL GULF WATERS AND PORTIONS OF THE NORTHWEST
AFTER 00Z. THIS IS CONSISTENT WITH THE 12Z GFS SHOWING A PIECE OF
ENERGY ROTATING AROUND THE BASE OF THE TROUGH AND ACROSS CENTRAL
FLORIDA OVERNIGHT. SO WILL KEEP 20-30 POPS FOR THIS REGION.
THE UPPER TROUGH ALONG THE EASTERN SEABOARD WILL BEGIN TO FILL AND
LIFT TO THE NORTHEAST TONIGHT AND WEDNESDAY...BUT A WEAKNESS WILL
REMAIN OVER THE GULF AND THE WESTERN ATLANTIC THROUGH THE WEEKEND.
AT THE SURFACE...THE QUASI-STATIONARY FRONT OVER NORTH FLORIDA
WILL SLOWLY DRIFT SOUTHWARD TONIGHT INTO WEDNESDAY AND THEN BEGIN
TO WASH OUT AND DRIFT NORTHWARD INTO THURSDAY. THE SUBTROPICAL
RIDGE OVER THE WESTERN ATLANTIC WILL MOVE NORTHWARD AND THE DRY
AIR AND HAZE OVER THE BAHAMAS IS EXPECTED TO PUSH INTO SOUTH
FLORIDA ON WEDNESDAY AND THURSDAY. IN ADDITION...THE LOW/MID LEVEL
FLOW WILL SHIFT FROM THE SOUTHWEST TO THE EAST AND SOUTHEAST BY
THURSDAY.
WITH PWATS FALLING TO AROUND 1.5 INCHES ON WEDNESDAY ALONG THE
SOUTHEAST COAST...ONLY MINIMAL RAIN CHANCES ARE EXPECTED.
STEERING FLOW WILL PUSH STORMS SLOWLY TO THE NORTH ON WEDNESDAY.
HIGHER MOISTURE WILL ALSO LINGER AROUND THE LAKE ON WEDNESDAY...SO
THERE WILL STILL BE A CHANCE OF STORMS FOR THE LAKE OKEECHOBEE
REGION. MODEL SOUNDINGS ARE SHOWING RELATIVELY STEEP LAPSE RATES
ABOVE THE INVERSION AND STRONG STORMS AND POSSIBLY AN ISOLATED
SEVERE STORM CANNOT BE RULED OUT ON WEDNESDAY. HEAT INDICES WILL
BE THE TYPICAL 100-108F FOR THIS TIME OF YEAR...WITH THE HIGHEST
READINGS ACROSS THE INTERIOR.
EVEN DRIER AIR IS EXPECTED TO MOVE INTO THE REGION ON
THURSDAY...WITH PWATS ACROSS THE REGION DROPPING TO 1.3-1.6 INCHES.
WITH THE FLOW SHIFTING TO THE EAST AND SOUTHEAST...EXPECT THE EAST
COAST TO MAINLY STAY DRY...WITH ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS THE INTERIOR AND TOWARDS THE GULF COAST.
FOR FRIDAY INTO SATURDAY...THE PRESSURE GRADIENT MAY BEGIN TO
TIGHTEN AS TROPICAL DEPRESSION NINE MOVES NEAR HAITI AND EASTERN
CUBA. SO SOMEWHAT BREEZIER EASTERLY FLOW COULD BEGIN ON FRIDAY AND
SATURDAY WITH AN INCREASE IN LOW LEVEL MOISTURE AND RAIN CHANCES.
IT IS STILL TOO EARLY TO DETERMINE THE IMPACTS OF TROPICAL
DEPRESSION NINE ON SOUTH FLORIDA OR THE SURROUNDING MARINE AREAS IN
THE LONG TERM. HOWEVER...THERE IS INCREASING POTENTIAL THAT SOUTH
FLORIDA AND/OR THE SURROUNDING MARINE AREAS COULD BE IMPACTED LATE
THIS WEEKEND INTO EARLY NEXT WEEK. SO NOW IS A GOOD TIME TO
REVIEW INDIVIDUAL TROPICAL CYCLONE PREPAREDNESS PLANS. FOR THE
LATEST INFORMATION REGARDING TROPICAL DEPRESSION NINE...CONTINUE
TO MONITOR THE LATEST FORECASTS FROM THE NATIONAL HURRICANE
CENTER.
AVIATION...
A FEW THUNDERSTORMS COULD DEVELOP THIS AFTERNOON
MAINLY TOWARD KPBI AND KFXE, BUT EXPECT TO HAVE ACTIVITY CLOSE
ENOUGH TO THE REST OF THE ERN TERMINALS TO BE WORTH MENTIONING
VCTS IN TAFS. WL EXPECT ANY SHWR/TSTM TO REMAIN WELL AWAY FROM
KAPF AND NO AFFECT OPERATIONS. EVENING ACTIVITY SHOULD TAPER OFF
BY 00Z TONIGHT. SFC SHOULD REMAIN MOSTLY SE, ALTHOUGH BECOMING
LIGHT AND VARIABLE AFTER 00Z AND INCREASING AGAIN TO AROUND 8-10
KTS AFTER 13Z WEDNESDAY.
MARINE...
A RIDGE OF HIGH PRESSURE WILL BE LOCATED OVER THE SOUTH FLORIDA
WATERS THROUGH THE MIDDLE OF THE WEEK BEFORE SHIFTING NORTH DURING
THE LATTER PART OF THE WEEK. THIS WILL LEAD TO WINDS OUT OF THE
SOUTH BECOMING EASTERLY LATE IN THE WEEK. THE PRESSURE GRADIENT IS
EXPECTED TO INCREASE FRIDAY AND SATURDAY AS TROPICAL DEPRESSION
NINE MOVES NEAR HAITI AND EASTERN CUBA. THE FORECAST FOR LATE THIS
WEEKEND BECOMES HIGHLY DEPENDENT ON THE EVOLUTION THIS TROPICAL
CYCLONE. THE FORECAST TRACK OF THIS POTENTIAL SYSTEM IS IN THE
GENERAL DIRECTION OF THE REGIONAL WATERS AND SHOULD BE CLOSELY
MONITORED BY ALL MARINE INTERESTS OVER THE COMING DAYS.
FIRE WEATHER...
SOUTH TO SOUTHWEST WINDS WILL BE OVER SOUTH FLORIDA AGAIN ON
WEDNESDAY AS A HIGH PRESSURE RIDGE PERSISTS JUST SOUTH OF THE
AREA OVER THE KEYS AND FLORIDA STRAITS. ISOLATED TO SCATTERED
THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THE AFTERNOON ON
WEDNESDAY BUT AFFECTING MAINLY THE INTERIOR AND THE LAKE
OKEECHOBEE REGION AS THE ACTIVITY WILL MOVE TO THE NORTHEAST. EAST
AND WEST COAST SEA BREEZES ARE EXPECTED TO DEVELOP LATE THIS
MORNING AND CONTINUE INTO THIS AFTERNOON ON WEDNESDAY. FLOW WILL
BECOME MORE EASTERLY ON THURSDAY AND STRENGTHEN FRIDAY INTO THE
WEEKEND AS THE PRESSURE GRADIENT INCREASES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 91 78 89 / 30 20 10 10
FORT LAUDERDALE 80 91 80 91 / 20 20 10 10
MIAMI 79 92 79 91 / 20 10 10 10
NAPLES 77 93 77 93 / 30 30 20 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...57/DG
AVIATION/RADAR...60/BD
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 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 DODGE CITY KS
621 PM CDT TUE AUG 21 2012
...UPDATED AVIATION SECTION...
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 100 PM CDT TUE AUG 21 2012
TONIGHT:
THE SHORT TERM METEOROLOGICAL CONCERN IS WHAT TO DO WITH POPS FOR THIS
EVENING. MESOSCALE (NAM, WRF) AND GLOBAL MODELS (GFS, ECMWF) PAINT DOUBT
ON CONVECTIVE PROSPECTS FOR THE EVENING. THIS IS A RESULT OF THE FACT
THAT THE UPPER LEVEL JET/WAVE IS EAST OF THE REGION AND CONVERGENCE
AT THE SURFACE IS FORECAST TO BE WEAK. 850 HPA THETA-E ADVECTION IS
FORECAST TO REMAIN WEAK AS WELL. RECENT HRRR RUNS HAS BEEN INDICATING
ISOLATED ACTIVITY ACROSS THE WESTERN ZONES THIS EVENING BUT THIS MODEL
HAS BEEN TRENDING DOWNWARD OVERALL IN THE LAST SEVERAL RUNS. AS A RESULT,
HAVE REMOVED WX FROM THE GRIDS AND GOING WITH A DRY FORECAST FOR THIS
EVENING. SOUTHERLY WINDS WILL CONTINUE THROUGH THE OVERNIGHT WITH MODERATE
DEWPOINTS AS WELL. LOOK FOR LOWS IN THE LOWER 60S DEG F.
TOMORROW:
THE LEE SURFACE TROUGH WILL STRENGTHEN TOMORROW AS MID TO UPPER LEVEL
FLOW BECOMES A BIT MORE PERPENDICULAR TO THE ROCKIES. I HAVE POPS INCREASING
UP TO THE SLIGHT CATEGORY TOWARDS 00Z TOMORROW EVENING AS WEAK 850 HPA
THETA-E ADVECTION STRENGTHENS AND SOME STORMS COULD FORM NEAR THE LEE
SURFACE TROUGH ACROSS THE W/NW ZONES. OTHERWISE, TOMORROW WILL BE MAINLY
DRY WITH HIGHS IN THE UPPER 80S TO AROUND 90 DEG F. THESE VALUES ARE
VERY CLOSE TO CLIMATOLOGY FOR THIS TIME OF YEAR. TOMORROW WILL BE A
BIT BREEZY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 204 PM CDT TUE AUG 21 2012
THIS WEEK IS SHAPING UP INTO A RELATIVELY WET PATTERN. THE UPPER
LEVEL FLOW IS EVOLVING INTO A MORE PROGRESSIVE PATTERN WITH SHORT
AND LONG WAVES TRAVELING THROUGH THE UPPER PLAINS AND MIDWEST AT A
FAIRLY REGULAR INTERVAL. WE WILL BE ON THE SOUTH END OF MINOR
WAVES, WHICH WILL OVERFLOW AFTERNOON LEE SIDE SURFACE TROUGHS DURING
THE LATE AFTERNOON AND OVERNIGHT PERIODS. THEREFORE, PRECIPITATION
CHANCES WILL BE IN THE RANGE OF 30 PERCENT WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT AS A WEAK LOBE OF VORTICITY SCRAPES WEST TO EAST
THROUGH WESTERN KANSAS. THEN ON EARLY FRIDAY, A STRONGER WAVE UP
NORTH MOVING THROUGH THE DAKOTAS WILL SWING A MORE SIGNIFICANT WAVE
THROUGH KANSAS. DURING THE TIME FROM WEDNESDAY TO FRIDAY, DEW
POINTS WILL BE INCREASING INTO THE MID 60S TO LOWER 70S, ALLOWING
THE POTENTIAL FOR SOME HEAVY RAIN IN OUR SOUTHEAST COUNTIES FRIDAY
NIGHT AND SATURDAY AS THE LOWER LAYER BECOMES MORE SATURATED. THAT
WAVE WILL NOT GO DIRECTLY THROUGH OUR FORECAST AREA, BUT WILL DRAG
SLOWLY THROUGH WESTERN KANSAS ON A NORTHWEST TO SOUTHEAST
ORIENTATION. THIS WILL ALLOW A SURFACE FRONT TO STAY NEARLY
ANCHORED OVER OUR CENTRAL TO SOUTHEASTERN ZONES, AND SHOWERS AND
THUNDERSTORMS WILL CONTINUE TO RE-FIRE ALONG AND SOUTHEAST OF THE
FRONTAL BOUNDARY. POPS WILL BUMP UP INTO THE 40 TO 50 PERCENT
RANGE, FOR SOME OF OUR EASTERN ZONES, WITH 60 PERCENT POPS FRIDAY
NIGHT AND AGAIN SATURDAY NIGHT ACROSS OUR SOUTHEASTERN ZONES,
SOUTHEAST OF A LINE FROM LARNED TO MEADE. DECIDED TO NOT GO AS HIGH
AS THE ECMWF MODEL IS FORECASTING THE QPF TO BE (ABOUT 4 INCHES
TOTAL QPF WED TO SUN) SOUTHEAST OF A PRATT TO ASHLAND LINE, BUT
NEARER THE 2 INCH RANGE, WHICH IS CLOSER TO THE GFS OUTPUT. THE
WAVE WILL BE NEARLY EXITING OUR EASTERN CWA BY SUNDAY, BUT SMALL 20
PERCENT POPS WILL LINGER SUNDAY MORNING ACROSS OUR EXTREME EASTERN
ZONES. AN UPPER LEVEL RIDGE WILL BUILD IN FROM THE SOUTH MONDAY,
AND SHOULD KEEP BOTH MONDAY AND TUESDAY DRY.
MAXIMUM TEMPERATURES WEDNESDAY AND THURSDAY WILL REACH THE NEAR 90F
RANGE, BUT THEN A COLD FRONT MOVING IN FRIDAY WILL BRING CLOUDS AND
PRECIPITATION TO HELP LOWER MAX T`S INTO THE MIDDLE TO UPPER 80S
SATURDAY. MAX TEMPS WILL BASICALLY STAY IN THE 80S SUNDAY AS WELL,
THEN BEGIN REBOUNDING UPWARD MONDAY AND TUESDAY INTO THE LOWER 90S.
WINDS DO NOT LOOK TO BE TOO STRONG THROUGH THE WED NT THROUGH TUE
PERIOD, BUT WILL MAINTAIN A SOUTHERLY FLOW SUNDAY INTO TUESDAY.
MINIMUM TEMPERATURES IN THE LOWER TO MIDDLE 60S THURSDAY WILL RISE
TO THE MIDDLE 60S NORTHWEST TO LOWER TO MID 70S SOUTHEAST FRIDAY,
SATURDAY, SUNDAY, MONDAY AND TUESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 619 PM CDT TUE AUG 21 2012
VFR CONDITIONS WILL PREVAIL WITH MOSTLY CLEAR SKIES ANTICIPATED
TONIGHT THROUGH TOMORROW. WEAK LEE TROUGHING ACROSS EASTERN
COLORADO WILL ALLOW SOUTHERLY WINDS TO CONTINUE SHIFTING TO THE
SOUTH SOUTHWEST TOMORROW MORNING. A FEW GUSTS AROUND 20 KNOTS WILL
BE POSSIBLE STARTING LATE TOMORROW MORNING AS THE ATMOSPHERE MIXES
AND THE PRESSURE GRADIENT TIGHTENS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 61 89 65 91 / 10 10 30 30
GCK 61 91 64 92 / 10 10 30 30
EHA 61 89 63 91 / 10 10 20 30
LBL 60 90 64 91 / 10 10 30 30
HYS 60 91 65 92 / 10 10 30 30
P28 61 91 66 90 / 10 10 30 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUGDEN
LONG TERM...BURKE
AVIATION...HOVORKA_42
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 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 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
1034 PM EDT TUE AUG 21 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL CROSS THE AREA OVERNIGHT WITH SHOWERS
AND THUNDERSTORMS COMING TO AN END. HIGH PRESSURE WILL BUILD OVER
THE REGION WEDNESDAY KEEPING CONDITIONS MOSTLY DRY WITH NEAR
NORMAL TEMPERATURES INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
03Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO MAKE
SLIGHT ADJUSTMENTS TO THE POP GRIDS TO ACCOUNT FOR LINGERING
CONVECTION.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A POSITIVE TILTED
500MB TROUGH ACROSS THE REGION WITH ITS AXIS EXTENDING NE TO SW
ACROSS OHIO. VORT ENERGY IS CENTERED ALONG THIS IS AXIS AND THIS
FEATURE CONTINUES TO INSTIGATE A FEW LINGERING ISOLATED SHOWERS
AND THUNDERSTORMS ACROSS THE UPPER OHIO VALLEY.
OVERNIGHT...THE MID-LEVEL TROUGH AXIS WILL TRANSLATE EASTWARD INTO
WESTERN PA. THIS FEATURE WILL CONTINUE TO PROVIDE FORCING FOR AT
LEAST A FEW ISOLATED SHOWERS INITIALLY AS IT SHIFTS EASTWARD. WITH
THE LOSS OF HEATING AND THE SUPPORT OF HIRES MESOSCALE MODELS,
CONVECTION IS FORECAST TO DIMINISH COMPLETELY BY AROUND MIDNIGHT.
ANOTHER NIGHT OF CLEARING SKIES AND NEAR CALM WINDS WILL ALLOW FOR
RADIATION FOG TO DEVELOP DURING THE PRE-DAWN HOURS, ESPECIALLY
ALONG THE RIVER VALLEYS. FOR TEMPS, FORECAST CONSISTS OF A
MAV/MET BLEND, WITH LOWS RANGING FROM THE LOW TO MID 50S ACROSS
THE FORECAST AREA.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
UPPER LEVEL TROUGH WILL CONTINUE TO WEAKEN AND MOVE NORTHWARD
THROUGH THE EARLY PART OF WEDNESDAY. ONCE THE TROUGH BREAKS
DOWN, THE REGION WILL BE OVERCOME WITH ZONAL FLOW ALOFT. HIGH
PRESSURE WILL BUILD OVER THE REGION BRINGING DRY CONDITIONS WITH
TEMPERATURES MODERATING CLOSER TO NORMAL TO ABOVE NORMAL ON
FRIDAY. ADJUSTED TEMPERATURES USING A BLEND OF MOS AND GFS GUIDANCE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
CONSENSUS OF RECENT ECMWF AND NAEFS MODEL OUTPUT CONTINUES TO
SHOW BROAD HIGH PRESSURE, UNDER WEAK FLOW ALOFT, MAINTAINING DRY
CONDITIONS ACROSS THE EASTERN U.S. INTO THE WEEKEND IF NOT MONDAY.
AS THE CENTER OF THIS HIGH PRESSURE PASSES EAST TO THE ATLANTIC
COAST MONDAY, SURFACE SOUTHERLY WINDS WILL BRING AN INCREASE IN
SURFACE DEW POINTS INTO THE LOWER 60S.
THE MODEL OUTPUT NEXT SHOWS A LOW PRESSURE SYSTEM, COMING EAST FROM
THE PLAINS, PROVIDING THE UPPER OHIO VALLEY WITH A CHANCE OF SHOWERS
AND THUNDERSTORMS MONDAY NIGHT AND TUESDAY.
DUE TO THE RELATIVE LACK OF CLOUDS INTO MONDAY, CONTINUE TO EXPECT
EACH DAY TO HAVE A LARGER THAN NORMAL DIURNAL TEMPERATURE RANGE.
HENCE CONCUR WITH HPC THINKING...WITH SUPPORT FROM RECENT GFS AND
ECMWF MOS AND NAEFS MEDIAN VALUES...THAT LOWS SATURDAY WILL BE CLOSE
TO NORMAL, WHILE INCREASED LOW LEVEL HUMIDITY MAY PROMOTE LOWS UP TO
5 DEGREES WARMER THAN NORMAL SUNDAY INTO TUESDAY. HIGH TEMPERATURES
WILL BE GENERALLY UP TO 5 DEGREES WARMER THAN NORMAL, ALTHOUGH
EXTENT OF SHOWERS COULD REDUCE HIGHS TUESDAY.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
EXPECT MAINLY VFR THROUGH WEDNESDAY. SCATTERED SHOWERS WILL PERSIST
THIS EVENING ESPECIALLY FOR THE NORTHERN PORTS OF KFKL AND KDUJ WHERE
ISOLATED THUNDERSTORMS ARE ALSO POSSIBLE BEFORE MIDNIGHT. SHOWERS
WILL DIMINISH IN COVERAGE AND INTENSITY AFTER MIDNIGHT. BRIEF MVFR
CONDITIONS ARE POSSIBLE IN THE SHOWERS.
THERE IS ALSO A RISK OF RESTRICTIONS DUE TO RIVER VALLEY FOG 08Z-13Z
WITH A PERIOD OF MVFR TO IFR VSBY POSSIBLE AROUND DAYBREAK.
.OUTLOOK/ WEDNESDAY NIGHT THROUGH SUNDAY/...
MAINLY VFR, EXCEPT FOR POSSIBLE RESTRICTIONS DUE TO EARLY MORNING
RIVER VALLEY FOG.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
726 PM EDT TUE AUG 21 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL CROSS THE AREA OVERNIGHT WITH SHOWERS
AND THUNDERSTORMS COMING TO AN END. HIGH PRESSURE WILL BUILD OVER
THE REGION WEDNESDAY KEEPING CONDITIONS MOSTLY DRY WITH NEAR
NORMAL TEMPERATURES INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
00Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO ACCOUNT
FOR THE LATEST TRENDS IN SKY, POP, AND TEMP GRIDS.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A POSITIVE TILTED
500MB TROUGH ACROSS THE REGION WITH ITS AXIS EXTENDING NE TO SW
ACROSS OHIO. VORT ENERGY IS CENTERED ALONG THIS IS AXIS AND THIS
FEATURE CONTINUES TO INSTIGATE CONVECTION ACROSS THE UPPER OHIO
VALLEY. LAPS ANALYSIS INDICATES MUCH OF THE AREA WORKED OVER WITH
100-200 J/KG OF CIN FROM EARLIER SHOWERS AND THUNDERSTORMS. BEST
REMAINING INSTABILITY (500-1000 J/KG SBCAPE) IS ACROSS EASTERN
OHIO. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE TO
MOVE ACROSS THE AREA ARE ON AN OVERALL DECREASING TREND IN
INTENSITY WITH THE LOSS OF HEATING/INSTABILITY THIS EVENING.
OVERNIGHT...THE MID-LEVEL TROUGH AXIS WILL TRANSLATE EASTWARD INTO
WESTERN PA. THIS FEATURE WILL CONTINUE TO PROVIDE FORCING FOR AT
LEAST THE SCHC OF SHOWERS INITIALLY AS IT SHIFTS EASTWARD. WITH
THE LOSS OF HEATING AND THE SUPPORT OF HIRES MESOSCALE MODELS,
CONVECTION IS FORECAST TO DIMINISH COMPLETELY BY AROUND MIDNIGHT.
ANOTHER NIGHT OF CLEARING SKIES AND NEAR CALM WINDS WILL ALLOW FOR
RADIATION FOG TO DEVELOP DURING THE PRE-DAWN HOURS, ESPECIALLY
ACROSS THE RIVER VALLEYS. FOR TEMPS, FORECAST CONSISTS OF A
MAV/MET BLEND, WITH LOWS RANGING FROM THE LOW TO MID 50S ACROSS
THE FORECAST AREA.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
UPPER LEVEL TROUGH WILL CONTINUE TO WEAKEN AND MOVE NORTHWARD
THROUGH THE EARLY PART OF WEDNESDAY. ONCE THE TROUGH BREAKS
DOWN, THE REGION WILL BE OVERCOME WITH ZONAL FLOW ALOFT. HIGH
PRESSURE WILL BUILD OVER THE REGION BRINGING DRY CONDITIONS WITH
TEMPERATURES MODERATING CLOSER TO NORMAL TO ABOVE NORMAL ON
FRIDAY. ADJUSTED TEMPERATURES USING A BLEND OF MOS AND GFS GUIDANCE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
CONSENSUS OF RECENT ECMWF AND NAEFS MODEL OUTPUT CONTINUES TO
SHOW BROAD HIGH PRESSURE, UNDER WEAK FLOW ALOFT, MAINTAINING DRY
CONDITIONS ACROSS THE EASTERN U.S. INTO THE WEEKEND IF NOT MONDAY.
AS THE CENTER OF THIS HIGH PRESSURE PASSES EAST TO THE ATLANTIC
COAST MONDAY, SURFACE SOUTHERLY WINDS WILL BRING AN INCREASE IN
SURFACE DEW POINTS INTO THE LOWER 60S.
THE MODEL OUTPUT NEXT SHOWS A LOW PRESSURE SYSTEM, COMING EAST FROM
THE PLAINS, PROVIDING THE UPPER OHIO VALLEY WITH A CHANCE OF SHOWERS
AND THUNDERSTORMS MONDAY NIGHT AND TUESDAY.
DUE TO THE RELATIVE LACK OF CLOUDS INTO MONDAY, CONTINUE TO EXPECT
EACH DAY TO HAVE A LARGER THAN NORMAL DIURNAL TEMPERATURE RANGE.
HENCE CONCUR WITH HPC THINKING...WITH SUPPORT FROM RECENT GFS AND
ECMWF MOS AND NAEFS MEDIAN VALUES...THAT LOWS SATURDAY WILL BE CLOSE
TO NORMAL, WHILE INCREASED LOW LEVEL HUMIDITY MAY PROMOTE LOWS UP TO
5 DEGREES WARMER THAN NORMAL SUNDAY INTO TUESDAY. HIGH TEMPERATURES
WILL BE GENERALLY UP TO 5 DEGREES WARMER THAN NORMAL, ALTHOUGH
EXTENT OF SHOWERS COULD REDUCE HIGHS TUESDAY.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
EXPECT MAINLY VFR THROUGH WEDNESDAY. SCATTERED SHOWERS WILL PERSIST
THIS EVENING ESPECIALLY FOR THE NORTHERN PORTS OF KFKL AND KDUJ WHERE
ISOLATED THUNDERSTORMS ARE ALSO POSSIBLE BEFORE MIDNIGHT. SHOWERS
WILL DIMINISH IN COVERAGE AND INTENSITY AFTER MIDNIGHT. BRIEF MVFR
CONDITIONS ARE POSSIBLE IN THE SHOWERS.
THERE IS ALSO A RISK OF RESTRICTIONS DUE TO RIVER VALLEY FOG 08Z-13Z
WITH A PERIOD OF MVFR TO IFR VSBY POSSIBLE AROUND DAYBREAK.
.OUTLOOK/ WEDNESDAY NIGHT THROUGH SUNDAY/...
MAINLY VFR, EXCEPT FOR POSSIBLE RESTRICTIONS DUE TO EARLY MORNING
RIVER VALLEY FOG.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
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 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
724 PM EDT TUE AUG 21 2012
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 412 PM EDT TUE AUG 21 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF OVER
THE UPR GRT LKS BTWN UPR TROF OVER ERN CAN/NE CONUS THAT IS SLOWLY
LIFTING OUT AND AN UPR RDG IN THE ROCKIES/PLAINS. SFC HI PRES
CENTERED OVER SW WI/LGT WLY FLOW ON ITS NRN FLANK AS WELL AS VERY
DRY AIR SHOWN ON THE 12Z INL/MPX RAOBS ARE BRINGING A TRANQUIL DRY
DAY TO UPR MI. THE ONLY FLY IN THE OINTMENT IS SOME MAINLY HI CLDS
DRIFTING SEWD INTO MAINLY THE E HALF OF THE CWA. THESE CLDS ARE ON
THE SRN FLANK OF AREA OF THICKER CLDS/A FEW -SHRA OVER ONTARIO
ASSOCIATED WITH DEEPER MSTR DEPICTED ON THE 12Z YPL RAOB AND WAD IN
ADVANCE OF SHRTWV EMBEDDED IN NW FLOW ALF AND NOW MOVING INTO FAR NW
ONTARIO.
MAIN FCST CONCERNS THRU WED WL BE PCPN CHCS ASSOCIATED WITH SHRTWV
FCST TO DROP SEWD THRU ONTARIO.
TNGT...SHRTWV NOW MOVING INTO FAR NW ONTARIO AND ASSOCIATED SFC LO
IS PROGGED TO DRIFT SEWD TO JUST W OF JAMES BAY BY 12Z WED.
ATTENDANT SFC TROF IS FCST TO STRETCH FM SFC LO WSWD THRU NRN LK SUP
TO NEAR ISLE ROYALE. THE EXPECTED MOTION OF THE SHRTWV INDICATES
BEST DPVA/DEEPER DEEP LYR QVECTOR CNVGC WL REMAIN FOCUSED IN ONTARIO.
ANOTHER SIGNIFICANT DETRIMENT TO PCPN CHCS WL BE VERY DRY LLVL AIR
SHOWN ON THE 12Z MPX/INL RAOBS AS INCRSG LLVL WSW FLOW TO THE S OF
SFC-H85 TROF WL BE DRAWING THIS AIR TOWARD UPR MI. SO ALTHOUGH
MODELS SHOW AN EXPANDING AREA OF H7 MSTR RELATED TO ISENTROPIC
ASCENT ON THE 305K SFC...NAM FCST SDNGS INDICATE THIS MOISTER LYR WL
BE RATHER THIN AND CAP MUCH DRIER LLVLS. THE GFS SHOWS MORE LLVL
MSTR...BUT WL TEND TO FOLLOW THE NAM GUIDANCE CONSIDERING THE
DRYNESS OF THE LLVLS OBSVD UPSTREAM. FOR THESE REASONS...OPTED TO GO
DRY TNGT AND LIMIT SCHC POPS ONLY TO THE FAR NRN CWA NEAR INCOMING
SFC TROF. OTRW...INCRSG WSW FLOW WL TEND TO LIMIT THE DIURNAL TEMP
FALL...ESPECIALLY IN DOWNSLOPE AREAS NEAR LK SUP THAT WL ALSO SEE
MORE AC RELATED TO H7 MOISTENING OVERNGT.
WED...SHRTWV TO THE NE IS PROGGED TO SLIDE TO THE E...TAKING DEEP
LYR QVECTOR CNVGC/H7 MSTR WITH IT. IN THE ABSENCE OF SGNFT MID LVL
FORCING AND WITH LLVL DRY AIR LINGERING TO THE S OF SFC LO PRES
TROF...THINK PCPN CHCS ARE MINIMAL. ALTHOUGH THE 12Z GFS GENERATES
SOME SPOTTY LGT QPF OVER PORTIONS OF MAINLY THE NCNTRL AND E...
OPTED TO FOLLOW THE BULK OF OTHER GUIDANCE AND KEEP THE LAND CWA
DRY...WITH SCHC POPS RESTRICTED TO NE LK SUP...CLOSER TO MID LVL
FORCING/MSTR. WITH H85 TEMPS PROGGED TO PEAK FM ARND 15C OVER THE E
TO 17C OVER THE W...EXPECT A WARMER DAY. DEEP MIXING ON NAM FCST
SDNGS SUG HI TEMPS WL REACH THE MID 80S OVER THE INTERIOR. A
WEAKENING PRES GRADIENT IN THE AFTN WL ALLOW FOR LK BREEZES TO FORM
AND MODERATE TEMPS NEAR THE LKSHORES.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 412 PM EDT TUE AUG 21 2012
WEDNESDAY NIGHT...
WILL BEGIN WITH NW FLOW ALOFT AT 00Z THURSDAY /AND A WEAK SFC FRONT
NEARLY STATIONARY W TO E OVER THE CWA/...WITH A WEAK 500MB RIDGE SET
UP ALONG THE RED RIVER VALLEY OF THE N. EXPECT THIS RIDGE TO PUSH
ACROSS THE UPPER GREAT LAKES THURSDAY MORNING INTO THE EARLY
AFTERNOON HOURS...BEFORE GETTING PUSHED E /THANKS THE TO THE E
MOTION OF THE CURRENT TROUGH SET UP LONG THE PACIFIC COAST/. WEAK S
FLOW SHOULD HELP KEEP TEMPS ROUGHLY 5F WARMER THAN TONIGHT.
THURSDAY AFTERNOON THROUGH FRIDAY NIGHT...
LOOK FOR THE N EXTENT OF THE PACIFIC TROUGH TO PUSH ACROSS THE
DAKOTAS THURSDAY MORNING...AND ACROSS THE UPPER GREAT LAKES THURSDAY
AFTERNOON INTO THURSDAY NIGHT. FCST MODELS ARE PRETTY CONSISTENT IN
HAVING THE TROUGH DIRECTLY OVERHEAD AT 18Z FRIDAY...BEFORE SHIFTING
NE TO ONTARIO AND W QUEBEC. THE MAIN CONCERN WOULD STILL BE SLIGHTLY
STRONGER S WINDS FRIDAY MORNING W INTO THE AFTERNOON HOURS E.
SATURDAY THROUGH SUNDAY...
A STRONGER 500MB LOW WILL POSITION ITSELF OVER S SASKATCHEWAN
SATURDAY MORNING...AND CENTRAL MANITOBA BY 06Z SUNDAY. THE NEARLY
STACKED SYSTEM SHOULD RESULT THE FRONTAL BOUNDARY OVER THE CWA
LIFTING N AS A WARM FRONT...AND WARMER AIR SURGING N FOR
SATURDAY...WITH WIDESPREAD 80 DEGREE TEMPS AS 850MB TEMPS PUSH INTO
THE 16-18C RANGE. MUCH OF THE CLOUD COVER AND PRECIP SHOULD SHOULD
REMAIN W...CLOSER TO THE NEARING COLD FRONT ACROSS E ND AND W MN.
THE 21/00Z CANADIAN MODEL...WHILE HAVING A SIMILAR IDEA...IS ON THE
NORTHERN FRINGE OF SOLUTIONS. ON THE OTHER HAND...THE 21/06Z GFS IS
A BIT FARTHER SOUTH. THE DIFFERENCE FROM THE 2 IS ROUGHLY
200MI...WHICH IS NOT TOO BAD FOR A 120HR OR MORE FCST. THESE
DIFFERENCES BECOME A BIT MORE PRONOUNCED ACROSS S HUDSON BAY/N
ONTARIO SUNDAY NIGHT...BUT SHOULD NOT IMPACT OUR FCST TOO
GREATLY...AS A TROUGH WILL CONTINUE TO DOMINATE THE UPPER GREAT
LAKES REGION /SATURDAY NIGHT THROUGH AT LEAST SUNDAY NIGHT/.
MONDAY AND TUESDAY...
WRAP AROUND MOISTURE WILL BE POSSIBLE WITH COOLER AIR SLIDING IN ON
NW WINDS OFF THE GFS. HOWEVER...THIS IS HIGHLY DEPENDENT ON WHERE
THE STILL RELATIVELY STACKED LOW DECIDES TO GO. THE MORE PROGRESSIVE
N LOW OFF THE ECMWF STILL TRIES TO AMPLIFY THE SYSTEM TO OUR S
/ACROSS MO/IA/IL/WI/...WITH ANOTHER ROUND OF SHOWERS AND POSSIBLY TS
MONDAY MORNING AND AFTERNOON MAINLY CENTRAL AND E.
THE 21/00Z ECMWF AND 06Z GFS BECOME COMPLETELY OUT OF PHASE OVER THE
PACIFIC NW BY 00Z SUNDAY WRT THE 500MB PATTERN. LUCKILY THIS DOES
NOT SEEM TO NEGATIVELY IMPACT THE UPPER GREAT LAKES REGION UNTIL
MONDAY AFTERNOON/EVENING. AS A RESULT OF AN EXTREMELY LOW CONFIDENCE
FORECAST BEYOND MONDAY...WILL NOT TRY TO DO TOO MUCH OVER CLIMO. BY
DAYBREAK TUESDAY THE GFS HAS A SIZABLE TROUGH ACROSS THE GREAT
LAKES...WHILE THE ECMWF SHIFTS A HIGH AMPLITUDE RIDGE OVERHEAD. THE
MAIN CONCERN WITH A SOLID MODEL BLEND WOULD BE THE ISSUES PRODUCED
BY THE GFS AND CONVECTIVE FEEDBACK. ON A POSITIVE NOTE...THE 12Z
GFS/ECMWF DO LOOK A LITTLE MORE IN AGREEMENT FOR MONDAY AND
TUESDAY...WITH A RIDGE BUILDING IN MONDAY NIGHT INTO TUESDAY. WILL
SEE IF THIS TREND HOLDS UP WITH THE 18Z GFS AND 00Z RUNS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 723 PM EDT TUE AUG 21 2012
NO CHANGES TO EXPECTED CONDITIONS SINCE PREVIOUS DISCUSSION BELOW...
WITH RELATIVELY DRY LOW-LEVELS...VFR CONDITIONS WILL PREVAIL THRU
THIS FCST PERIOD AT KIWD/KCMX/KSAW. MODEST LOW-LEVEL JET ARRIVING
OVERNIGHT TONIGHT WILL LEAD TO POSSIBLE LLWS...MAINLY AT KCMX WHICH
WILL BE CLOSER TO AXIS OF SPEED MAX. WITH DAYTIME HEATING ON WED...
THESE STRONGER WINDS WILL MIX OUT AND RESULT IN A GUSTY WSW WIND.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 PM EDT TUE AUG 21 2012
EXPECT SW WINDS VEERING W TO INCREASE UP TO 25 KTS LATER TONIGHT/
EARLY WED...STRONGEST IN THE AREA BETWEEN THE KEWEENAW AND ISLE
ROYALE WHERE TERRAIN ACCENTUATES THIS FLOW...AS A LO PRES TROF
PRESSES INTO LAKE SUPERIOR FROM ONTARIO. LIGHT WINDS WILL THEN
PREVAIL FROM WED AFTERNOON INTO THE WEEKEND BEFORE THE APPROACH OF A
STRONGER DISTURBANCE/COLD FRONT MIGHT CAUSE S-SW WINDS TO INCREASE
UP TO 25 KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KC
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 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 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...UPDATED
NWS NORTH PLATTE NE
623 PM CDT TUE AUG 21 2012
.AVIATION...
VISUAL FLIGHT RULES ARE EXPECTED OVER WESTERN NEBRASKA TONING HT
AND WEDNESDAY. ON WEDNESDAY A TROUGH OF LOW PRESSURE WILL MOVE OUT
OF THE NEBRASKA PANHANDLES LATE IN THE AFTERNOON WITH ISOLATED HIGH
BASED TRW AOA 12K FT. MODERATE SOUTHERLY FLOW AHEAD OF THE SYSTEM
BUT MINIMAL LOW LEVEL MOISTURE IS EXPECTED. STRONG ERRATIC WINDS
ARE POSSIBLE IN THE VICINITY OF TRW`S.
&&
.PREV DISCUSSION... /ISSUED 412 PM CDT TUE AUG 21 2012/
UPDATE...
DISCUSSION...
RADAR INDICATES ISOLATED THUNDERSTORMS MAY BE DEVELOPING A BIT
FARTHER NORTH THAN FCST BY THE HRRR. SO A MINOR ADJUSTMENT FOR
ISOLATED EVENING TSTMS HAS BEEN MADE ACROSS FAR SOUTHERN
NEBRASKA.
PREV DISCUSSION... /ISSUED 332 PM CDT TUE AUG 21 2012/
DISCUSSION...
AN AREA OF WEAK CU IS FORMING ACROSS FAR SW NEB THIS AFTERNOON.
THE HRRR SUGGEST ISOLATED STORM DEVELOPMENT WITH STORM MOTION
SOUTHEAST AND AWAY FROM THE FCST AREA. OTHERWISE NO SIGNIFICANT
WEATHER IS EXPECTED OVERNIGHT. LOW PRESSURE ACROSS THE NRN HIGH
PLAINS AND A WARM FRONT STRETCHING ACROSS NRN NEB SHOULD KEEP MIN
TEMPS WARMER TONIGHT. THE SFC LOW IS EXPECTED TO BEGIN MOVING
SLOWLY SOUTH OVERNIGHT.
ON WEDNESDAY...THE LOW DROPS SOUTH TOWARD SWRN SD AND NW NEB BY
LATE AFTERNOON. MOISTURE ALOFT WILL INCREASE AHEAD OF A WEAK NRN
STREAM DISTURBANCE. THE COMBINATION OF THE DISTURBANCE ACROSS THE
NRN PLAINS...INCREASING MOISTURE ALOFT AND STRONG SFC HEATING
SHOULD PRODUCE ISOLATED LATE AFTERNOON TSTMS. MODEL QPF IS
IGNORING THE VERY DRY AIR BELOW 700 MB AND PRODUCING QPF AS HIGH
AS .66 INCHES. THE NAM INDICATED DELTA T-TD HIGHER THAN 40 DEGREES
YET STILL PRODUCED 2/3 OF AN INCH OF QPF. SO POPS ARE LIMITED TO
THE ISOLATED CATEGORY. K INDICES IN THE MODEL ARE BELOW 40C WHICH
IS GENERALLY THE LIMIT FOR SCATTERED STORM COVERAGE. WE WILL SEE
IF THE MODELS CAN SHOW DEEPER MOISTURE BEFORE RAISING FCST POPS.
IN THE WAKE OF THE DISTURBANCE WEDNESDAY NIGHT...A WEAK COLD FRONT
WILL DROP THROUGH WRN NEB IN THE MORNING ANGLED SW THROUGH KIML AND INTO
A SFC HEAT LOW ACROSS ERN COLO. THE FRONT WILL DRIFT SOUTH AND
EAST THROUGHOUT THE AFTERNOON. SOUTHWEST WINDS BELOW 700 MB WILL HAVE
EVACUATED WHATEVER MOISTURE WAS THERE AND THE DEPARTING UPPER
LEVEL DISTURBANCE WILL DRY OUT THE ATM ALOFT. THUS NO RAIN IS EXPECTED
THURSDAY EXCEPT PERHAPS ACROSS CNTL NEB DEPENDING ON THE LOCATION
OF THE FRONT.
A DEEP UPPER LEVEL DISTURBANCE WILL BE TRACKING THROUGH SRN
ALBERTA AND SRN SASKATCHEWAN FRIDAY. THIS SYSTEM SHOULD DRAW DEEPER
MOISTURE FROM TEXAS NORTH THROUGH WRN NEB DURING THE AFTERNOON AND
SUFFICIENT UPPER LEVEL FORCING SHOULD BE AVAILABLE FOR ISOLATED
STORM DEVELOPMENT FRIDAY AFTERNOON. A BROAD AREA OF STRATUS MAY DEVELOP
FRIDAY MORNING AS MOISTURE LIFTS NORTH. ALL SOLNS EXCEPT THE NAM12
SHOW THIS FORMING.
TEMPERATURES ARE EXPECTED TO RISE INTO THE 90S WEDNESDAY THROUGH
FRIDAY. VERTICAL MIXING PROFILES MAY BE LIMITED AS THE SFC LOW
WILL GENERALLY DROP DUE SOUTH THROUGH THE HIGH PLAINS VS TRACKING
EAST THROUGH SRN SD. SO MAX TEMPS FOLLOW A MIDDLE OF THE ROAD
APPROACH FOR A MIX OF HIGHS IN THE LOWER...MIDDLE AND A FEW UPPER 90S.
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY.
DECENT LOW AND MID LEVEL MOISTURE WILL SPREAD NORTH INTO THE AREA
FROM THE SOUTH FRIDAY NIGHT AHEAD OF A DECENT MID LEVEL DISTURBANCE.
850 MB DEW PTS PER THE ECMWF ARE PROGGED TO RISE TO NEAR 16C.
CHANCES FOR RAIN ARE EXPECTED TO INCREASE SATURDAY AS THE
DISTURBANCE MOVES ACROSS THE AREA...BUT RIGHT NOW MODELS INDICATING
THE BEST FOCUS FOR RAINFALL/CONVECTION MAY STAY SOUTH AND EAST OF
THE AREA. SO WON/T GET CARRIED AWAY WITH POPS...AND JUST CONTINUE
THE INHERITED 40 PERCENT CHANCES. SYSTEM MOVES EAST OF THE AREA
SUNDAY...WITH DRY WEATHER EXPECTED THE FIRST OF NEXT WEEK.
TEMPERATURE WISE...NEAR SEASONAL HIGHS IN THE 80S ARTE EXPECTED FOR
THE WEEKEND. BY EARLY NEXT WEEK HIGHS COULD REACH BACK INTO THE
LOWER 90S. LOWS WILL BE QUITE MILD WITH THE INCREASED
MOISTURE...WITH MOST AREAS STAYING IN THE 60S AT NIGHT.
FIRE WEATHER... BREEZY SOUTHERLY WINDS WILL INCREASE WEDNESDAY IN
RESPONSE TO A TIGHTENING PRESSURE GRADIENT ACROSS THE AREA. SOME
INCREASE IN LOW LEVEL MOISTURE IS EXPECTED...AND MINIMUM RELATIVE
HUMIDITY VALUES ARE EXPECTED TO REMAIN ABOVE 20 PERCENT. THE NAM
MODEL MAY BE DRYING OUT THE LOW LEVELS A LITTLE TOO MUCH ACROSS
CENTRAL NEBRASKA BASED ON WHAT IS OCCURRING TODAY...AND WILL FORGO
A FIRE WEATHER WATCH FOR THE THAT AREA AT THIS TIME.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...POWER
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 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 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 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 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
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 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
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 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 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 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 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
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
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 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 LA CROSSE WI
653 PM CDT TUE AUG 21 2012
.SHORT TERM...THROUGH THURSDAY NIGHT
230 PM CDT TUE AUG 21 2012
MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES WEDNESDAY THROUGH
THURSDAY NIGHT.
SURFACE ANALYSIS THIS AFTERNOON SHOWS HIGH PRESSURE CENTERED OVER
EASTERN IOWA INTO CENTRAL WISCONSIN.
THE FIRST CONCERN IS WHETHER ANY VALLEY FOG WILL FORM AGAIN
TONIGHT. THE SURFACE HIGH WILL BE PULLING OFF TO THE SOUTHEAST AND
SHOULD BE CENTERED OVER INDIANA BY LATE TONIGHT. BOTH THE 21.12Z
NAM AND GFS SUGGEST A WARM FRONT WILL DEVELOP IN THE RETURN FLOW
FROM SOUTH DAKOTA INTO MISSOURI. AS THIS OCCURS...BOTH MODELS
ACTUALLY SHOW A LITTLE BIT OF RIDGING DEVELOPING NORTH OF THE
FRONT AND OVER THE AREA. THIS SHOULD ALLOW THE SURFACE WINDS TO
DECOUPLE ONCE AGAIN AND DEW POINTS SHOULD RECOVER INTO THE UPPER
40S. SKIES WILL BE CLEAR OVERNIGHT SO PLENTY OF POSITIVES FOR THE
FOG. BOTH THE NAM AND 21.17Z RAP BUFKIT SOUNDING FOR KLSE SHOW
SOUTHWEST WINDS AROUND 20 KNOTS JUST ABOVE THE SURFACE UP THROUGH
ABOUT 3 OR 4 THOUSAND FEET. THIS IS VERY SIMILAR TO A COUPLE OF
NIGHTS AGO EXPECT THE WINDS ARE ABOUT 180 DEGREES DIFFERENT IN
DIRECTION AND MAYBE A LITTLE STRONGER TONIGHT. SOME FOG DID FORM
IN THESE SIMILAR CONDITIONS SATURDAY MORNING SO PLAN TO INCLUDE A
MENTION OF PATCHY FOG.
THE NEXT CONCERN IS WHETHER ANY RAIN WILL FORM WEDNESDAY AND
WEDNESDAY NIGHT IN THE RETURN FLOW. MODEL DIFFERENCES CONTINUE
WITH THE NAM AND GFS STILL SHOWING SOME RAIN DEVELOPING WHILE THE
21.00Z ECMWF REMAINS DRY. WHETHER THIS RAIN DEVELOPS OR NOT
DEPENDS ON HOW MUCH LOW LEVEL THERMODYNAMICS COME INTO PLAY. THE
NAM CONTINUES TO BE THE STRONGEST WITH THIS FORCING SHOWING WEAK
FRONTOGENESIS IN THE 1000-500 MB LAYER NORTH OF THE WARM FRONT.
THE ECMWF ALSO HAS A LITTLE BIT OF FRONTOGENESIS BUT ONLY UP
THROUGH 700 MB. THE BIG DIFFERENCE COMES IN THE ISENTROPIC
RESPONSE. THE NAM GENERATES UP TO 10 UBAR/S ON THE 310K SURFACE
WHILE THE GFS ONLY HAS ABOUT 3 UBAR/S AND THE ECMWF HAS BETWEEN 1
AND 2 UBAR/S. IF THIS RAIN DOES DEVELOP...THE NAM BUFKIT SOUNDINGS
SHOW CLOUD BASES WOULD BE ABOUT 10K FEET WITH LOTS OF DRY AIR
BELOW. WOULD NOT EXPECT MUCH MORE THAN SOME SPRINKLES OR A QUICK
SHOWER WITH A COUPLE HUNDREDTHS QPF.
THE MODEL DIFFERENCES CONTINUE INTO THURSDAY AND THURSDAY NIGHT AS
WELL. THE SHORT WAVE TROUGH COMING ONTO THE PACIFIC NORTHWEST
COAST TODAY WILL TOP THE ROCKIES AND START MOVING ACROSS THE UPPER
MIDWEST. THE ECMWF HAS BEEN VERY CONSISTENT SHOWING THE FILLING
UPPER LEVEL LOW WITH THIS SYSTEM TO BE MOVING NORTHEAST INTO
CENTRAL CANADA WHILE THE SHORT WAVE TROUGH COMES THROUGH WITH A
POSITIVE TILT. THE NAM AND GFS ARE SUGGESTING THAT A PIECE OF
ENERGY WILL BREAK OUT OF THE MEAN LONG WAVE TROUGH AXIS OR A NEW
SHORT WAVE TROUGH DEVELOPS IN THE LEE OF THE ROCKIES WEDNESDAY.
THESE MODELS THEN BRING THIS SHORT WAVE TROUGH ACROSS THE AREA
WITH A NEUTRAL TO NEGATIVE TILT AND QUICKER THAN THE POSITIVE
TILT OF THE ECMWF. AT THIS POINT...CONFIDENCE ON WHICH SOLUTION
WILL VERIFY IS NOT HIGH SO HAVE TRIED TO COMPROMISE BETWEEN THE
TWO WITH A SLIGHT NOD TOWARD THE ECMWF SOLUTION. WILL SHOW A SMALL
CHANCE OF RAIN ACROSS THE FAR NORTH THURSDAY MORNING AHEAD OF THE
ADVANCING WARM FRONT AND THEN 20 TO 30 PERCENT CHANCES DURING THE
AFTERNOON ACROSS THE WEST AND NORTH AS THE FORCING STARTS TO
INCREASE AHEAD OF THE APPROACHING SYSTEM. AS THE SHORT WAVE TROUGH
THEN COMES INTO LATER THURSDAY...IT SHOULD PRODUCE AROUND 4 PVU/S
OF VORTICITY ADVECTION IN THE 500-300 MB LAYER. NOT MUCH OF
SURFACE REFLECTION WITH THIS SYSTEM SO ONLY SOME WEAK
FRONTOGENESIS IN THE 1000-850 MB LAYER. SOME WEAK UP GLIDE OF 1-2
UBAR/S SHOULD CONTINUE ON THE 310K SURFACE ALONG WITH GETTING
INTO THE EASTERN AND CONVERGENT SIDE OF THE MOISTURE TRANSPORT
AXIS. ALL THIS FORCING LOOKS TO BE AT ITS STRONGEST THURSDAY NIGHT
ACROSS THE NORTH AND DID INCREASE THE RAIN CHANCE TO AROUND 60
THERE.
.LONG TERM...FRIDAY THROUGH TUESDAY
230 PM CDT TUE AUG 21 2012
THE RAIN THAT DEVELOPS THURSDAY/THURSDAY NIGHT SHOULD BE COMING TO
AN END FRIDAY INTO FRIDAY NIGHT AS THE SHORT WAVE TROUGH MOVES
PAST THE AREA. THE NEXT PIECE OF ENERGY WILL QUICKLY APPROACH FROM
THE WEST COAST WITH THE UPPER LEVEL LOW AGAIN MOVING ACROSS CANADA
ALLOWING A SOUTHWEST FLOW ALOFT TO DEVELOP ACROSS THE UPPER
MIDWEST. INITIALLY THE MODELS ARE IN GOOD AGREEMENT THAT A SHORT
WAVE TROUGH WILL BE IN THIS SOUTHWEST FLOW OVER THE MID PLAINS
STATES SATURDAY NIGHT BUT THEN DIVERGE AS THEY START TO LIFT THIS
WAVE NORTHEAST. THE GFS FLATTENS THIS WAVE OUT AND LIFTS IT
THROUGH QUICKER THAN EITHER THE 21.12Z GEM OR ECMWF. THE ECMWF IS
THE STRONGEST AND SLOWEST LIFTING THIS WAVE TO THE NORTHEAST. THE
DIFFERENCES COULD BE STEMMING FROM THE WIDE RANGE OF SOLUTIONS
THAT ARE SHOWING UP WITH A POTENTIAL TROPICAL SYSTEM APPROACHING
THE SOUTHEAST U.S. AND FOR NOW HAVE STAYED WITH THE MODEL
CONSENSUS GRIDS WITH 30 TO 50 PERCENT RAIN CHANCES SATURDAY NIGHT
THROUGH SUNDAY NIGHT WITH THE SYSTEM THEN MOVING PAST MONDAY.
&&
.AVIATION...TONIGHT AND WEDNESDAY
653 PM CDT TUE AUG 21 2012
FORECAST CONCERNS THIS PERIOD ARE OVERNIGHT VALLEY FOG POTENTIAL
AT KLSE AND PRECIPITATION CHANCES WEDNESDAY AFTERNOON. HIGH
PRESSURE WILL DRIFT EAST OF THE AREA TONIGHT...MAINTAINING CLEAR
SKIES AND LIGHT SURFACE WINDS. ANOTHER DAY OF DRYING/MIXING WITH
A 34 DEGREE T/TD SPREAD AT KLSE LATE THIS AFTERNOON SUPPORTS A
TOUGH DEWPOINT RECOVERY TONIGHT. FORECAST 03Z SPREADS ARE RATHER
LARGE...UPWARDS TO 10-15F. ANOTHER NEGATIVE FOG FACTOR...AND
PROBABLY MORE IMPORTANT...IS THE WINDS OFF THE SURFACE. LATEST
MODEL SOUNDINGS SHOW 15 TO 22 KTS AT 500 FT THROUGH NEARLY 3 KFT.
THIS SETUP PROBABLY WOULD LEAD TO MORE STRATUS THAN FOG...BUT
GIVEN REALLY DRY BOUNDARY LAYER...THINKING IS THAT STRATUS MAY NOT
BE ABLE TO DEVELOP EITHER. IN SHORT...THE COMBINATION OF DRY AIR
AND STRONG WINDS SHOULD PRECLUDE WIDESPREAD FOG/STRATUS AT KLSE.
A WARM FRONT WILL LIFT ACROSS MINNESOTA/IOWA WEDNESDAY
AFTERNOON...BRINGING INCREASING CLOUDS WITH BASES AT ABOUT 10 KFT.
SCATTERED SHOWERS AND MAYBE A THUNDERSTORM MAY DEVELOP ALONG
THIS FRONT...BUT CONFIDENCE IS NOT HIGH ENOUGH AT THIS TIME TO
INCLUDE IN TAF. A TIGHTER PRESSURE GRADIENT AND DAYTIME MIXING
SUPPORTS WINDS GUSTING UP TO 18 KTS AT KRST DURING THE AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
230 PM CDT TUE AUG 21 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...ZT
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
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 SAN DIEGO CA
915 PM PDT TUE AUG 21 2012
.SYNOPSIS...
THE COMBINATION OF MONSOON MOISTURE AND A TROUGH MOVING TOWARDS
CENTRAL CALIFORNIA WILL ALLOW FOR ADDITIONAL SCATTERED SHOWERS AND
THUNDERSTORMS TONIGHT THROUGH WEDNESDAY. THE ASSOCIATED TROUGH WILL
MOVE JUST EAST OF THE REGION ON THURSDAY AND ALLOW FOR DRIER AIR FOR
MOST AREAS. THE MARINE LAYER WILL CONTINUE TO DEEPEN THROUGH
WEDNESDAY AND THEN LINGER INTO THURSDAY. UPPER LEVEL HIGH PRESSURE
WILL REBUILD OVER THE AREA FRIDAY AND SATURDAY WITH DRY CONDITION.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
.THIS AFTERNOON AND EVENING...WIDELY SCATTERED STRONG TO SEVERE
THUNDERSTORMS DEVELOPED THIS AFTERNOON ALONG THE SAN DIEGO CREST
AND TRACKED NORTHEAST INTO THE DESERT SLOPES. THE STRONGEST STORM
WAS NEAR MOUNT LAGUNA AND WAS CARRIED INTO THE DESERT SLOPES WHILE
ANOTHER CELL IMPACTED HIGHWAY 78 EAST OF SHELTER VALLEY AND A THIRD
LARGE STORM IN SANTA ROSA MOUNTAINS. ISOLATED THUNDERSTORMS THAT
OCCURRED IN LUCERNE AND JOHNSON VALLEY HAVE REDEVELOPED THIS PAST
HOUR. SPC SURFACE ANALYSIS DEPICTS SBCAPE (INSTABILITY) HAS SHIFTED
TO THE EASTERN AREAS WITH THE WESTERN EDGE OVER LUCERNE VALLEY.
HOWEVER MUCAPE (MOST UNSTABLE) DEPICTS WIDESPREAD 100 TO 500 J/KG
EXTENDING WEST OVER THE COASTAL WATERS. THIS IS DEPICTED IN THE 00Z
UPPER AIR KNKX SOUNDING WITH 1.91 PRECIPITABLE WATER AND SOUTHWEST
FLOW AT 600 TO 500 MB LAYER WHICH WAS STEERING FLOW FOR THE STORMS
TODAY. MOIST LAYER IS ABOUT 800 MB UP TO 500 MB WITH THIS TOPPED
WITH DRY AIR ALOFT. VERY CONDUCIVE TO ELEVATED CONVECTION...GIVEN
SYNOPTIC LIFTING OF THE LAYER TO REACH THE LEVEL OF FREE CONVECTION
AND THE COOL ADIABATIC LAPSE RATE RESPONSE OF THE DRY AIR ALOFT.
THIS PROCESS EXPECTED WHILE THE AIR MASS DECOUPLES OVERNIGHT.
.TONIGHT...WELL DEFINED SHORT WAVE TROUGH APPROACHING POINT
CONCEPTION AND SIGNS OF CLOSING OFF IN THE CORE WITH A PV TAIL
EXTENDING SOUTH TO JUST NORTHWEST OF OUR COASTAL WATER OF SOUTHWEST
CALIFORNIA. AT SUNSET A BAND OF ALTOCUMULUS WAS EVIDENT OVER THE
STRATUS DECK WEST OF PORT CONCEPTION. THE 00Z NAM CONTINUES TO DEPICT
AN AREA OF QVECTOR CONVERGENCE OVER LA COUNTY AND ACROSS MOST
OF OUR FORECAST AREA STARTING NEAR 06Z WHICH SHIFTS EAST AND IS
LINED FROM JOHNSON VALLEY TO THE SAN DIEGO DESERTS BY 12Z. THIS IS
ALSO ALIGNED WITH A WELL DEFINED 700 MB NEAR SATURATED MOISTURE
FIELD WITHIN THE SOUTHERLY FLOW FROM 700 TO 500 MB. SUBSIDENCE
SWEEPS IN QUICKLY FROM WEST TO EAST AFTER 12Z. THEREFORE...GIVEN THE
SYNOPTIC LIFT ENTERING OUR REGION AND THE OBSERVED ELEVATED CAPE IN
PLACE ALONG A DOUBLE AXIS OF PRECIPITABLE WATER (ONE OVER THE
COASTAL WATERS AND ONE OVER FAR SOUTHERN CALIFORNIA) THE THREAT FOR
THE DEVELOPMENT OF ELEVATED MOIST CONVECTION REMAINS. THESE EVENTS
OFTEN DEVELOP QUICKLY AND ARE ALIGNED WITH THE MEAN FLOW ALOFT WHILE
THEY SHIFT EASTWARD AS AN AREA BUT BUILD SOUTHWARD WITH PROPAGATION
ALONG THE CYCLONIC FLOW AND SYNOPTIC LAYER LIFT ALOFT. MODEL
SOUNDINGS HAVE THIS ELEVATED CAPE LAYER SUFFICIENT OVERNIGHT THROUGH
WEDNESDAY MORNING. WE SHOULD SEE CLOUD DEVELOPMENT AND EXPANSION
DURING NEXT COUPLE HOURS OVER SOUTHWEST CALIFORNIA.
PAST SEVERAL RUNS OF THE HRRR MODEL HAVE DEVELOPED SOME CONVECTION
(BUT VARIOUS DEGREE OF COVERAGE) ALONG AND TO THE EAST (MOVING AWAY
IN PREVAILING FLOW) FROM SAN DIEGO COUNTY NORTHWARD INTO WESTERN SAN
BERNARDINO COUNTY.
.WEDNESDAY AND THURSDAY...WHILE MOIST OF THE CONVECTION IS SHUNTED
EAST WITH THE UPPER TROUGH AFTER WEDNESDAY MORNING...THE WESTERN
EDGE OF THE TROPICAL MOISTURE FIELDS REMAINS INTO THE AFTERNOON WITH
THE MAIN SIGNIFICANT COOLING ALOFT. THEREFORE ISOLATED ADDITIONAL
THUNDERSTORMS SHOULD FORM OVER THE HIGH TERRAIN CREST BUT QUICKLY
LIFT EASTWARD ACROSS THE DESERTS DUE TO THE STRONGER SOUTHWEST FLOW
JUST AHEAD OF THE UPPER TROUGH AXIS.
THE SLOW MOVING UPPER TROUGH AXIS SHIFTS EAST OF THE AREA BY THURSDAY
AND UPPER LEVEL FLOW BECOMES NORTHERLY (SOUTHERLY LOWER LEVELS).
MOISTURE DOES LINGER FOR FAR EASTERN AREAS INTO THE LUCERNE AND
JOHNSON VALLEYS SO ISOLATED SHOWERS COULD STILL OCCUR IN THE
BACKSIDE CYCLONIC FLOW OF THE UPPER LOW. OTHERWISE THE DEEP MARINE
LAYER LINGERS BUT BEGINS TO BREAK UP.
.THURSDAY EVENING THROUGH TUESDAY AUGUST 28...CONSENSUS OF MODELS
SHOW HIGH PRESSURE RIDGE REBUILDING ACROSS THE AREA THROUGH SATURDAY
THEN SHIFTING EAST SUNDAY AND MONDAY...THEN THE UPPER RIDGE
FLATTENING ON TUESDAY AS ZONAL FLOW/STORM TRACK DEVELOPS ALONG 40N
LATITUDE. FOR SW CALIFORNIA THIS SHOULD YIELD A WARMING AND DRYING
TREND THROUGH SATURDAY WITH A LOWERING MARINE LAYER...THEN A SLIGHT
COOLING TREND WITH DEEPER MARINE LAYER AND GUSTY SOUTHWEST WINDS FOR
EARLY NEXT WEEK.
&&
.AVIATION...
220400Z...COAST/VALLEYS...STRATUS ALONG THE COAST WITH BASES 1000 FT
AND TOPS TO 1500 FT MSL SPREADING 15-20 SM INLAND THROUGH 15Z WED.
STRATUS CLEARING TOWARD THE COAST BTWN 17-19Z WED.
MTNS/DESERTS...SCT-BKN CLOUDS OVER THE MOUNTAINS AND DESERTS TONIGHT
WITH BASES FROM 15-20KFT. ON WEDNESDAY...SCT-BKN CUMULUS BUILDING
OVER THE MTNS GROWING INTO SCATTERED TSTMS BTWN 18Z-01Z WITH CLOUD
TOPS 40-50KFT.
&&
.FIRE WEATHER...ISOLATED TO SCATTERED LIGHTNING ACROSS LOWER
ELEVATIONS...DESERT SLOPES AND VALLEYS DUE TO THE ELEVATED NATURE OF
THUNDERSTORMS TONIGHT AND WEDNESDAY MORNING BRINGS SOME CONCERN.
UNCERTAINTY REMAINS WITH THE COVERAGE AND AMOUNT OF LIGHTNING. MOST
FAVORABLE AREAS ARE THE HIGH DESERTS AND ALONG AND TO THE EAST OF
I-15. AT THIS TIME HAVE LEFT THE FIRE WEATHER FORECAST PER
COORDINATION OF THE DAY SHIFT.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.
&&
$$
PUBLIC...TARDY
AVIATION/MARINE...MOEDE
AREA FORECAST DISCUSSION
NWS MIAMI FL
230 AM EDT WED AUG 22 2012
.AVIATION...
A LARGE SHIELD OF LIGHT TO MODERATE RAIN CONTINUES TO IMPACT THE
AREA FROM APF TO THE LAKE REGION EARLY THIS MORNING. EXPECT THIS
GENERAL TREND TO PERSIST THROUGH THE EARLY MORNING PERIOD...THEN
SHIFT INLAND AND ACROSS THE LAKE AND PALM BEACH REGION LATER
TODAY. IN ADDITION...PERIODS WITH HEAVIER SHRA/TSTMS EMBEDDED
WITHIN THIS ACTIVITY MOVING ASHORE ALONG THE GULF COAST WILL
REMAIN POSSIBLE THROUGH THIS TIME. THIS WILL RESULT IN PERIODS
WITH SUB VFR CIGS/VSBYS. OTHERWISE...THE LATEST NUMERICAL GUIDANCE
CONTINUES TO INDICATE DRIER AIR BEGINNING TO SPREAD NORTH ACROSS
SOUTH FLORIDA THROUGH THE COURSE OF THE DAY TODAY WITH THE WINDS
EXPECTED TO GRADUALLY BACK TOWARD THE EAST THROUGH THE PERIOD. 85/AG
&&
.PREV DISCUSSION... /ISSUED 1040 PM EDT TUE AUG 21 2012/
UPDATE...INCREASED POPS AREA WIDE FOR TONIGHT...ADDING ISOLATED
TSTORMS POTENTIAL TO THE EAST COAST AND SCATTERED ACTIVITY FOR THE
INTERIOR AND GULF COAST BASED ON LATEST RADAR TRENDS OF ACTIVITY
MOVING IN FROM THE GULF AND CONVECTION AGAIN MOVING OFF OF CUBA
WHICH COULD IMPACT EASTERN AREAS OVERNIGHT. /GREGORIA
PREV DISCUSSION... /ISSUED 806 PM EDT TUE AUG 21 2012/
AVIATION...
LINGERING SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE ACROSS THE
REGION THIS EVENING. THE EAST COAST TERMINALS DO NOT HAVE ANY
THUNDERSTORMS IN THE VICINITY ALTHOUGH TERMINAL KPBI CURRENTLY HAS
LIGHT SHOWERS. MAINLY VFR CONDITIONS EXPECTED FOR THE EAST COAST
TERMINALS THIS EVENING ALTHOUGH KPBI COULD BRIEFLY HAVE SUB-VFR
CONDITIONS WITH ANY MODERATE SHOWERS OVER THE NEXT HOUR OR SO.
TERMINAL KAPF WAS ASSIGNED VCTS BUT SO FAR THUNDERSTORMS ARE NEAR
FT. MYERS AND ADJACENT GULF WATERS. IT IS POSSIBLE HOWEVER SOME
THUNDERSTORMS COULD MOVE ACROSS THE GULF WATERS AND AFFECT KAPF THIS
EVENING WITH SUB-VFR CONDITIONS IF THEY OCCUR AND WILL AMEND IF
NECESSARY.
60
PREV DISCUSSION... /ISSUED 209 PM EDT TUE AUG 21 2012/
DISCUSSION...
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS
THE INTERIOR AND PUSH TOWARDS THE NORTHEAST SECTIONS OF THE CWA THIS
AFTERNOON AND INTO THE EVENING UNDER THE SOUTHWEST FLOW ALOFT. A
FEW STORMS COULD BE STRONG...WITH THE MAIN THREAT BEING STRONG
WINDS OF 40 TO 50 MPH. THE HRRR IS SHOWING THAT A LINE OF STORMS
MAY MOVE ACROSS THE EASTERN GULF AND INTO CENTRAL FLORIDA...WITH
THE TAIL END OF THIS LINE OF SHOWERS AND THUNDERSTORMS POSSIBLY
MOVING INTO THE LOCAL GULF WATERS AND PORTIONS OF THE NORTHWEST
AFTER 00Z. THIS IS CONSISTENT WITH THE 12Z GFS SHOWING A PIECE OF
ENERGY ROTATING AROUND THE BASE OF THE TROUGH AND ACROSS CENTRAL
FLORIDA OVERNIGHT. SO WILL KEEP 20-30 POPS FOR THIS REGION.
THE UPPER TROUGH ALONG THE EASTERN SEABOARD WILL BEGIN TO FILL AND
LIFT TO THE NORTHEAST TONIGHT AND WEDNESDAY...BUT A WEAKNESS WILL
REMAIN OVER THE GULF AND THE WESTERN ATLANTIC THROUGH THE WEEKEND.
AT THE SURFACE...THE QUASI-STATIONARY FRONT OVER NORTH FLORIDA
WILL SLOWLY DRIFT SOUTHWARD TONIGHT INTO WEDNESDAY AND THEN BEGIN
TO WASH OUT AND DRIFT NORTHWARD INTO THURSDAY. THE SUBTROPICAL
RIDGE OVER THE WESTERN ATLANTIC WILL MOVE NORTHWARD AND THE DRY
AIR AND HAZE OVER THE BAHAMAS IS EXPECTED TO PUSH INTO SOUTH
FLORIDA ON WEDNESDAY AND THURSDAY. IN ADDITION...THE LOW/MID LEVEL
FLOW WILL SHIFT FROM THE SOUTHWEST TO THE EAST AND SOUTHEAST BY
THURSDAY.
WITH PWATS FALLING TO AROUND 1.5 INCHES ON WEDNESDAY ALONG THE
SOUTHEAST COAST...ONLY MINIMAL RAIN CHANCES ARE EXPECTED.
STEERING FLOW WILL PUSH STORMS SLOWLY TO THE NORTH ON WEDNESDAY.
HIGHER MOISTURE WILL ALSO LINGER AROUND THE LAKE ON WEDNESDAY...SO
THERE WILL STILL BE A CHANCE OF STORMS FOR THE LAKE OKEECHOBEE
REGION. MODEL SOUNDINGS ARE SHOWING RELATIVELY STEEP LAPSE RATES
ABOVE THE INVERSION AND STRONG STORMS AND POSSIBLY AN ISOLATED
SEVERE STORM CANNOT BE RULED OUT ON WEDNESDAY. HEAT INDICES WILL
BE THE TYPICAL 100-108F FOR THIS TIME OF YEAR...WITH THE HIGHEST
READINGS ACROSS THE INTERIOR.
EVEN DRIER AIR IS EXPECTED TO MOVE INTO THE REGION ON
THURSDAY...WITH PWATS ACROSS THE REGION DROPPING TO 1.3-1.6 INCHES.
WITH THE FLOW SHIFTING TO THE EAST AND SOUTHEAST...EXPECT THE EAST
COAST TO MAINLY STAY DRY...WITH ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS THE INTERIOR AND TOWARDS THE GULF COAST.
FOR FRIDAY INTO SATURDAY...THE PRESSURE GRADIENT MAY BEGIN TO
TIGHTEN AS TROPICAL DEPRESSION NINE MOVES NEAR HAITI AND EASTERN
CUBA. SO SOMEWHAT BREEZIER EASTERLY FLOW COULD BEGIN ON FRIDAY AND
SATURDAY WITH AN INCREASE IN LOW LEVEL MOISTURE AND RAIN CHANCES.
IT IS STILL TOO EARLY TO DETERMINE THE IMPACTS OF TROPICAL
DEPRESSION NINE ON SOUTH FLORIDA OR THE SURROUNDING MARINE AREAS IN
THE LONG TERM. HOWEVER...THERE IS INCREASING POTENTIAL THAT SOUTH
FLORIDA AND/OR THE SURROUNDING MARINE AREAS COULD BE IMPACTED LATE
THIS WEEKEND INTO EARLY NEXT WEEK. SO NOW IS A GOOD TIME TO
REVIEW INDIVIDUAL TROPICAL CYCLONE PREPAREDNESS PLANS. FOR THE
LATEST INFORMATION REGARDING TROPICAL DEPRESSION NINE...CONTINUE
TO MONITOR THE LATEST FORECASTS FROM THE NATIONAL HURRICANE
CENTER.
AVIATION...
A FEW THUNDERSTORMS COULD DEVELOP THIS AFTERNOON
MAINLY TOWARD KPBI AND KFXE, BUT EXPECT TO HAVE ACTIVITY CLOSE
ENOUGH TO THE REST OF THE ERN TERMINALS TO BE WORTH MENTIONING
VCTS IN TAFS. WL EXPECT ANY SHWR/TSTM TO REMAIN WELL AWAY FROM
KAPF AND NO AFFECT OPERATIONS. EVENING ACTIVITY SHOULD TAPER OFF
BY 00Z TONIGHT. SFC SHOULD REMAIN MOSTLY SE, ALTHOUGH BECOMING
LIGHT AND VARIABLE AFTER 00Z AND INCREASING AGAIN TO AROUND 8-10
KTS AFTER 13Z WEDNESDAY.
MARINE...
A RIDGE OF HIGH PRESSURE WILL BE LOCATED OVER THE SOUTH FLORIDA
WATERS THROUGH THE MIDDLE OF THE WEEK BEFORE SHIFTING NORTH DURING
THE LATTER PART OF THE WEEK. THIS WILL LEAD TO WINDS OUT OF THE
SOUTH BECOMING EASTERLY LATE IN THE WEEK. THE PRESSURE GRADIENT IS
EXPECTED TO INCREASE FRIDAY AND SATURDAY AS TROPICAL DEPRESSION
NINE MOVES NEAR HAITI AND EASTERN CUBA. THE FORECAST FOR LATE THIS
WEEKEND BECOMES HIGHLY DEPENDENT ON THE EVOLUTION THIS TROPICAL
CYCLONE. THE FORECAST TRACK OF THIS POTENTIAL SYSTEM IS IN THE
GENERAL DIRECTION OF THE REGIONAL WATERS AND SHOULD BE CLOSELY
MONITORED BY ALL MARINE INTERESTS OVER THE COMING DAYS.
FIRE WEATHER...
SOUTH TO SOUTHWEST WINDS WILL BE OVER SOUTH FLORIDA AGAIN ON
WEDNESDAY AS A HIGH PRESSURE RIDGE PERSISTS JUST SOUTH OF THE
AREA OVER THE KEYS AND FLORIDA STRAITS. ISOLATED TO SCATTERED
THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THE AFTERNOON ON
WEDNESDAY BUT AFFECTING MAINLY THE INTERIOR AND THE LAKE
OKEECHOBEE REGION AS THE ACTIVITY WILL MOVE TO THE NORTHEAST. EAST
AND WEST COAST SEA BREEZES ARE EXPECTED TO DEVELOP LATE THIS
MORNING AND CONTINUE INTO THIS AFTERNOON ON WEDNESDAY. FLOW WILL
BECOME MORE EASTERLY ON THURSDAY AND STRENGTHEN FRIDAY INTO THE
WEEKEND AS THE PRESSURE GRADIENT INCREASES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 91 78 89 79 / 20 10 10 20
FORT LAUDERDALE 91 80 91 79 / 10 10 10 20
MIAMI 92 79 91 78 / 10 10 10 20
NAPLES 93 77 93 76 / 40 20 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...15/JR
AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1231 AM CDT WED AUG 22 2012
...UPDATED AVIATION SECTION...
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 100 PM CDT TUE AUG 21 2012
TONIGHT:
THE SHORT TERM METEOROLOGICAL CONCERN IS WHAT TO DO WITH POPS FOR THIS
EVENING. MESOSCALE (NAM, WRF) AND GLOBAL MODELS (GFS, ECMWF) PAINT DOUBT
ON CONVECTIVE PROSPECTS FOR THE EVENING. THIS IS A RESULT OF THE FACT
THAT THE UPPER LEVEL JET/WAVE IS EAST OF THE REGION AND CONVERGENCE
AT THE SURFACE IS FORECAST TO BE WEAK. 850 HPA THETA-E ADVECTION IS
FORECAST TO REMAIN WEAK AS WELL. RECENT HRRR RUNS HAS BEEN INDICATING
ISOLATED ACTIVITY ACROSS THE WESTERN ZONES THIS EVENING BUT THIS MODEL
HAS BEEN TRENDING DOWNWARD OVERALL IN THE LAST SEVERAL RUNS. AS A RESULT,
HAVE REMOVED WX FROM THE GRIDS AND GOING WITH A DRY FORECAST FOR THIS
EVENING. SOUTHERLY WINDS WILL CONTINUE THROUGH THE OVERNIGHT WITH MODERATE
DEWPOINTS AS WELL. LOOK FOR LOWS IN THE LOWER 60S DEG F.
TOMORROW:
THE LEE SURFACE TROUGH WILL STRENGTHEN TOMORROW AS MID TO UPPER LEVEL
FLOW BECOMES A BIT MORE PERPENDICULAR TO THE ROCKIES. I HAVE POPS INCREASING
UP TO THE SLIGHT CATEGORY TOWARDS 00Z TOMORROW EVENING AS WEAK 850 HPA
THETA-E ADVECTION STRENGTHENS AND SOME STORMS COULD FORM NEAR THE LEE
SURFACE TROUGH ACROSS THE W/NW ZONES. OTHERWISE, TOMORROW WILL BE MAINLY
DRY WITH HIGHS IN THE UPPER 80S TO AROUND 90 DEG F. THESE VALUES ARE
VERY CLOSE TO CLIMATOLOGY FOR THIS TIME OF YEAR. TOMORROW WILL BE A
BIT BREEZY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 204 PM CDT TUE AUG 21 2012
THIS WEEK IS SHAPING UP INTO A RELATIVELY WET PATTERN. THE UPPER
LEVEL FLOW IS EVOLVING INTO A MORE PROGRESSIVE PATTERN WITH SHORT
AND LONG WAVES TRAVELING THROUGH THE UPPER PLAINS AND MIDWEST AT A
FAIRLY REGULAR INTERVAL. WE WILL BE ON THE SOUTH END OF MINOR
WAVES, WHICH WILL OVERFLOW AFTERNOON LEE SIDE SURFACE TROUGHS DURING
THE LATE AFTERNOON AND OVERNIGHT PERIODS. THEREFORE, PRECIPITATION
CHANCES WILL BE IN THE RANGE OF 30 PERCENT WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT AS A WEAK LOBE OF VORTICITY SCRAPES WEST TO EAST
THROUGH WESTERN KANSAS. THEN ON EARLY FRIDAY, A STRONGER WAVE UP
NORTH MOVING THROUGH THE DAKOTAS WILL SWING A MORE SIGNIFICANT WAVE
THROUGH KANSAS. DURING THE TIME FROM WEDNESDAY TO FRIDAY, DEW
POINTS WILL BE INCREASING INTO THE MID 60S TO LOWER 70S, ALLOWING
THE POTENTIAL FOR SOME HEAVY RAIN IN OUR SOUTHEAST COUNTIES FRIDAY
NIGHT AND SATURDAY AS THE LOWER LAYER BECOMES MORE SATURATED. THAT
WAVE WILL NOT GO DIRECTLY THROUGH OUR FORECAST AREA, BUT WILL DRAG
SLOWLY THROUGH WESTERN KANSAS ON A NORTHWEST TO SOUTHEAST
ORIENTATION. THIS WILL ALLOW A SURFACE FRONT TO STAY NEARLY
ANCHORED OVER OUR CENTRAL TO SOUTHEASTERN ZONES, AND SHOWERS AND
THUNDERSTORMS WILL CONTINUE TO RE-FIRE ALONG AND SOUTHEAST OF THE
FRONTAL BOUNDARY. POPS WILL BUMP UP INTO THE 40 TO 50 PERCENT
RANGE, FOR SOME OF OUR EASTERN ZONES, WITH 60 PERCENT POPS FRIDAY
NIGHT AND AGAIN SATURDAY NIGHT ACROSS OUR SOUTHEASTERN ZONES,
SOUTHEAST OF A LINE FROM LARNED TO MEADE. DECIDED TO NOT GO AS HIGH
AS THE ECMWF MODEL IS FORECASTING THE QPF TO BE (ABOUT 4 INCHES
TOTAL QPF WED TO SUN) SOUTHEAST OF A PRATT TO ASHLAND LINE, BUT
NEARER THE 2 INCH RANGE, WHICH IS CLOSER TO THE GFS OUTPUT. THE
WAVE WILL BE NEARLY EXITING OUR EASTERN CWA BY SUNDAY, BUT SMALL 20
PERCENT POPS WILL LINGER SUNDAY MORNING ACROSS OUR EXTREME EASTERN
ZONES. AN UPPER LEVEL RIDGE WILL BUILD IN FROM THE SOUTH MONDAY,
AND SHOULD KEEP BOTH MONDAY AND TUESDAY DRY.
MAXIMUM TEMPERATURES WEDNESDAY AND THURSDAY WILL REACH THE NEAR 90F
RANGE, BUT THEN A COLD FRONT MOVING IN FRIDAY WILL BRING CLOUDS AND
PRECIPITATION TO HELP LOWER MAX T`S INTO THE MIDDLE TO UPPER 80S
SATURDAY. MAX TEMPS WILL BASICALLY STAY IN THE 80S SUNDAY AS WELL,
THEN BEGIN REBOUNDING UPWARD MONDAY AND TUESDAY INTO THE LOWER 90S.
WINDS DO NOT LOOK TO BE TOO STRONG THROUGH THE WED NT THROUGH TUE
PERIOD, BUT WILL MAINTAIN A SOUTHERLY FLOW SUNDAY INTO TUESDAY.
MINIMUM TEMPERATURES IN THE LOWER TO MIDDLE 60S THURSDAY WILL RISE
TO THE MIDDLE 60S NORTHWEST TO LOWER TO MID 70S SOUTHEAST FRIDAY,
SATURDAY, SUNDAY, MONDAY AND TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1228 AM CDT WED AUG 22 2012
VFR CONDITIONS WILL PREVAIL WITH MOSTLY CLEAR SKIES ANTICIPATED
THROUGHOUT THE DAY. DEVELOPING LEE TROUGHING ACROSS EASTERN
COLORADO WILL ALLOW SOUTHERLY WINDS TO CONTINUE AROUND 10 KNOTS
THROUGH THE EARLY MORNING HOURS. A FEW GUSTS AROUND 20 KNOTS WILL
BE POSSIBLE STARTING LATE TOMORROW MORNING AS THE ATMOSPHERE MIXES
AND THE PRESSURE GRADIENT TIGHTENS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 65 91 67 86 / 30 30 30 30
GCK 64 92 66 88 / 30 30 20 20
EHA 63 91 66 88 / 20 30 20 30
LBL 64 91 67 87 / 30 30 30 30
HYS 65 92 67 87 / 30 30 30 20
P28 66 90 69 84 / 30 30 40 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUGDEN
LONG TERM...BURKE
AVIATION...HOVORKA_42
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
122 AM EDT WED AUG 22 2012
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 412 PM EDT TUE AUG 21 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF OVER
THE UPR GRT LKS BTWN UPR TROF OVER ERN CAN/NE CONUS THAT IS SLOWLY
LIFTING OUT AND AN UPR RDG IN THE ROCKIES/PLAINS. SFC HI PRES
CENTERED OVER SW WI/LGT WLY FLOW ON ITS NRN FLANK AS WELL AS VERY
DRY AIR SHOWN ON THE 12Z INL/MPX RAOBS ARE BRINGING A TRANQUIL DRY
DAY TO UPR MI. THE ONLY FLY IN THE OINTMENT IS SOME MAINLY HI CLDS
DRIFTING SEWD INTO MAINLY THE E HALF OF THE CWA. THESE CLDS ARE ON
THE SRN FLANK OF AREA OF THICKER CLDS/A FEW -SHRA OVER ONTARIO
ASSOCIATED WITH DEEPER MSTR DEPICTED ON THE 12Z YPL RAOB AND WAD IN
ADVANCE OF SHRTWV EMBEDDED IN NW FLOW ALF AND NOW MOVING INTO FAR NW
ONTARIO.
MAIN FCST CONCERNS THRU WED WL BE PCPN CHCS ASSOCIATED WITH SHRTWV
FCST TO DROP SEWD THRU ONTARIO.
TNGT...SHRTWV NOW MOVING INTO FAR NW ONTARIO AND ASSOCIATED SFC LO
IS PROGGED TO DRIFT SEWD TO JUST W OF JAMES BAY BY 12Z WED.
ATTENDANT SFC TROF IS FCST TO STRETCH FM SFC LO WSWD THRU NRN LK SUP
TO NEAR ISLE ROYALE. THE EXPECTED MOTION OF THE SHRTWV INDICATES
BEST DPVA/DEEPER DEEP LYR QVECTOR CNVGC WL REMAIN FOCUSED IN ONTARIO.
ANOTHER SIGNIFICANT DETRIMENT TO PCPN CHCS WL BE VERY DRY LLVL AIR
SHOWN ON THE 12Z MPX/INL RAOBS AS INCRSG LLVL WSW FLOW TO THE S OF
SFC-H85 TROF WL BE DRAWING THIS AIR TOWARD UPR MI. SO ALTHOUGH
MODELS SHOW AN EXPANDING AREA OF H7 MSTR RELATED TO ISENTROPIC
ASCENT ON THE 305K SFC...NAM FCST SDNGS INDICATE THIS MOISTER LYR WL
BE RATHER THIN AND CAP MUCH DRIER LLVLS. THE GFS SHOWS MORE LLVL
MSTR...BUT WL TEND TO FOLLOW THE NAM GUIDANCE CONSIDERING THE
DRYNESS OF THE LLVLS OBSVD UPSTREAM. FOR THESE REASONS...OPTED TO GO
DRY TNGT AND LIMIT SCHC POPS ONLY TO THE FAR NRN CWA NEAR INCOMING
SFC TROF. OTRW...INCRSG WSW FLOW WL TEND TO LIMIT THE DIURNAL TEMP
FALL...ESPECIALLY IN DOWNSLOPE AREAS NEAR LK SUP THAT WL ALSO SEE
MORE AC RELATED TO H7 MOISTENING OVERNGT.
WED...SHRTWV TO THE NE IS PROGGED TO SLIDE TO THE E...TAKING DEEP
LYR QVECTOR CNVGC/H7 MSTR WITH IT. IN THE ABSENCE OF SGNFT MID LVL
FORCING AND WITH LLVL DRY AIR LINGERING TO THE S OF SFC LO PRES
TROF...THINK PCPN CHCS ARE MINIMAL. ALTHOUGH THE 12Z GFS GENERATES
SOME SPOTTY LGT QPF OVER PORTIONS OF MAINLY THE NCNTRL AND E...
OPTED TO FOLLOW THE BULK OF OTHER GUIDANCE AND KEEP THE LAND CWA
DRY...WITH SCHC POPS RESTRICTED TO NE LK SUP...CLOSER TO MID LVL
FORCING/MSTR. WITH H85 TEMPS PROGGED TO PEAK FM ARND 15C OVER THE E
TO 17C OVER THE W...EXPECT A WARMER DAY. DEEP MIXING ON NAM FCST
SDNGS SUG HI TEMPS WL REACH THE MID 80S OVER THE INTERIOR. A
WEAKENING PRES GRADIENT IN THE AFTN WL ALLOW FOR LK BREEZES TO FORM
AND MODERATE TEMPS NEAR THE LKSHORES.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 412 PM EDT TUE AUG 21 2012
WEDNESDAY NIGHT...
WILL BEGIN WITH NW FLOW ALOFT AT 00Z THURSDAY /AND A WEAK SFC FRONT
NEARLY STATIONARY W TO E OVER THE CWA/...WITH A WEAK 500MB RIDGE SET
UP ALONG THE RED RIVER VALLEY OF THE N. EXPECT THIS RIDGE TO PUSH
ACROSS THE UPPER GREAT LAKES THURSDAY MORNING INTO THE EARLY
AFTERNOON HOURS...BEFORE GETTING PUSHED E /THANKS THE TO THE E
MOTION OF THE CURRENT TROUGH SET UP LONG THE PACIFIC COAST/. WEAK S
FLOW SHOULD HELP KEEP TEMPS ROUGHLY 5F WARMER THAN TONIGHT.
THURSDAY AFTERNOON THROUGH FRIDAY NIGHT...
LOOK FOR THE N EXTENT OF THE PACIFIC TROUGH TO PUSH ACROSS THE
DAKOTAS THURSDAY MORNING...AND ACROSS THE UPPER GREAT LAKES THURSDAY
AFTERNOON INTO THURSDAY NIGHT. FCST MODELS ARE PRETTY CONSISTENT IN
HAVING THE TROUGH DIRECTLY OVERHEAD AT 18Z FRIDAY...BEFORE SHIFTING
NE TO ONTARIO AND W QUEBEC. THE MAIN CONCERN WOULD STILL BE SLIGHTLY
STRONGER S WINDS FRIDAY MORNING W INTO THE AFTERNOON HOURS E.
SATURDAY THROUGH SUNDAY...
A STRONGER 500MB LOW WILL POSITION ITSELF OVER S SASKATCHEWAN
SATURDAY MORNING...AND CENTRAL MANITOBA BY 06Z SUNDAY. THE NEARLY
STACKED SYSTEM SHOULD RESULT THE FRONTAL BOUNDARY OVER THE CWA
LIFTING N AS A WARM FRONT...AND WARMER AIR SURGING N FOR
SATURDAY...WITH WIDESPREAD 80 DEGREE TEMPS AS 850MB TEMPS PUSH INTO
THE 16-18C RANGE. MUCH OF THE CLOUD COVER AND PRECIP SHOULD SHOULD
REMAIN W...CLOSER TO THE NEARING COLD FRONT ACROSS E ND AND W MN.
THE 21/00Z CANADIAN MODEL...WHILE HAVING A SIMILAR IDEA...IS ON THE
NORTHERN FRINGE OF SOLUTIONS. ON THE OTHER HAND...THE 21/06Z GFS IS
A BIT FARTHER SOUTH. THE DIFFERENCE FROM THE 2 IS ROUGHLY
200MI...WHICH IS NOT TOO BAD FOR A 120HR OR MORE FCST. THESE
DIFFERENCES BECOME A BIT MORE PRONOUNCED ACROSS S HUDSON BAY/N
ONTARIO SUNDAY NIGHT...BUT SHOULD NOT IMPACT OUR FCST TOO
GREATLY...AS A TROUGH WILL CONTINUE TO DOMINATE THE UPPER GREAT
LAKES REGION /SATURDAY NIGHT THROUGH AT LEAST SUNDAY NIGHT/.
MONDAY AND TUESDAY...
WRAP AROUND MOISTURE WILL BE POSSIBLE WITH COOLER AIR SLIDING IN ON
NW WINDS OFF THE GFS. HOWEVER...THIS IS HIGHLY DEPENDENT ON WHERE
THE STILL RELATIVELY STACKED LOW DECIDES TO GO. THE MORE PROGRESSIVE
N LOW OFF THE ECMWF STILL TRIES TO AMPLIFY THE SYSTEM TO OUR S
/ACROSS MO/IA/IL/WI/...WITH ANOTHER ROUND OF SHOWERS AND POSSIBLY TS
MONDAY MORNING AND AFTERNOON MAINLY CENTRAL AND E.
THE 21/00Z ECMWF AND 06Z GFS BECOME COMPLETELY OUT OF PHASE OVER THE
PACIFIC NW BY 00Z SUNDAY WRT THE 500MB PATTERN. LUCKILY THIS DOES
NOT SEEM TO NEGATIVELY IMPACT THE UPPER GREAT LAKES REGION UNTIL
MONDAY AFTERNOON/EVENING. AS A RESULT OF AN EXTREMELY LOW CONFIDENCE
FORECAST BEYOND MONDAY...WILL NOT TRY TO DO TOO MUCH OVER CLIMO. BY
DAYBREAK TUESDAY THE GFS HAS A SIZABLE TROUGH ACROSS THE GREAT
LAKES...WHILE THE ECMWF SHIFTS A HIGH AMPLITUDE RIDGE OVERHEAD. THE
MAIN CONCERN WITH A SOLID MODEL BLEND WOULD BE THE ISSUES PRODUCED
BY THE GFS AND CONVECTIVE FEEDBACK. ON A POSITIVE NOTE...THE 12Z
GFS/ECMWF DO LOOK A LITTLE MORE IN AGREEMENT FOR MONDAY AND
TUESDAY...WITH A RIDGE BUILDING IN MONDAY NIGHT INTO TUESDAY. WILL
SEE IF THIS TREND HOLDS UP WITH THE 18Z GFS AND 00Z RUNS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 121 AM EDT WED AUG 22 2012
NO CHANGES TO EXPECTED CONDITIONS SINCE PREVIOUS DISCUSSION BELOW...
WITH RELATIVELY DRY LOW-LEVELS...VFR CONDITIONS WILL PREVAIL THRU
THIS FCST PERIOD AT KIWD/KCMX/KSAW. MODEST LOW-LEVEL JET ARRIVING
OVERNIGHT TONIGHT WILL LEAD TO POSSIBLE LLWS...MAINLY AT KCMX AND
KIWD WHICH WILL BE CLOSER TO AXIS OF SPEED MAX. WITH DAYTIME HEATING
ON WED...THESE STRONGER WINDS WILL MIX OUT AND RESULT IN GUSTY WSW
WINDS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 PM EDT TUE AUG 21 2012
EXPECT SW WINDS VEERING W TO INCREASE UP TO 25 KTS LATER TONIGHT/
EARLY WED...STRONGEST IN THE AREA BETWEEN THE KEWEENAW AND ISLE
ROYALE WHERE TERRAIN ACCENTUATES THIS FLOW...AS A LO PRES TROF
PRESSES INTO LAKE SUPERIOR FROM ONTARIO. LIGHT WINDS WILL THEN
PREVAIL FROM WED AFTERNOON INTO THE WEEKEND BEFORE THE APPROACH OF A
STRONGER DISTURBANCE/COLD FRONT MIGHT CAUSE S-SW WINDS TO INCREASE
UP TO 25 KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1225 AM CDT WED AUG 22 2012
.AVIATION...
SOUTHERLY WINDS WILL STAY UP OVER NIGHT AND INCREASE THROUGH THE DAY
ON WEDNESDAY AHEAD OF SURFACE LOW PRESSURE SYSTEM MOVING ACROSS
WESTERN SOUTH DAKOTA. ISOLATED HIGH BASED THUNDERSTORMS ARE EXPECTED
OVER THE NEBRASKA PANHANDLE WEDNESDAY AFTERNOON SPREADING EAST INTO
NORTHERN NEBRASKA OVERNIGHT. WINDS WILL BE STRONG AND ERRATIC IN THE
VICINITY OF THUNDERSTORMS. DUE TO THE ISOLATED NATURE OF THE
THUNDERSTORMS DO NOT HAVE THE CONFIDENCE TO INCLUDE THEM IN ANY OF
THE TERMINAL FORECASTS.
&&
.PREV DISCUSSION... /ISSUED 623 PM CDT TUE AUG 21 2012/
UPDATE...
DISCUSSION...
RADAR INDICATES ISOLATED THUNDERSTORMS MAY BE DEVELOPING A BIT
FARTHER NORTH THAN FCST BY THE HRRR. SO A MINOR ADJUSTMENT FOR
ISOLATED EVENING TSTMS HAS BEEN MADE ACROSS FAR SOUTHERN
NEBRASKA.
PREV DISCUSSION... /ISSUED 332 PM CDT TUE AUG 21 2012/
DISCUSSION...
AN AREA OF WEAK CU IS FORMING ACROSS FAR SW NEB THIS AFTERNOON.
THE HRRR SUGGEST ISOLATED STORM DEVELOPMENT WITH STORM MOTION
SOUTHEAST AND AWAY FROM THE FCST AREA. OTHERWISE NO SIGNIFICANT
WEATHER IS EXPECTED OVERNIGHT. LOW PRESSURE ACROSS THE NRN HIGH
PLAINS AND A WARM FRONT STRETCHING ACROSS NRN NEB SHOULD KEEP MIN
TEMPS WARMER TONIGHT. THE SFC LOW IS EXPECTED TO BEGIN MOVING
SLOWLY SOUTH OVERNIGHT.
ON WEDNESDAY...THE LOW DROPS SOUTH TOWARD SWRN SD AND NW NEB BY
LATE AFTERNOON. MOISTURE ALOFT WILL INCREASE AHEAD OF A WEAK NRN
STREAM DISTURBANCE. THE COMBINATION OF THE DISTURBANCE ACROSS THE
NRN PLAINS...INCREASING MOISTURE ALOFT AND STRONG SFC HEATING
SHOULD PRODUCE ISOLATED LATE AFTERNOON TSTMS. MODEL QPF IS
IGNORING THE VERY DRY AIR BELOW 700 MB AND PRODUCING QPF AS HIGH
AS .66 INCHES. THE NAM INDICATED DELTA T-TD HIGHER THAN 40 DEGREES
YET STILL PRODUCED 2/3 OF AN INCH OF QPF. SO POPS ARE LIMITED TO
THE ISOLATED CATEGORY. K INDICES IN THE MODEL ARE BELOW 40C WHICH
IS GENERALLY THE LIMIT FOR SCATTERED STORM COVERAGE. WE WILL SEE
IF THE MODELS CAN SHOW DEEPER MOISTURE BEFORE RAISING FCST POPS.
IN THE WAKE OF THE DISTURBANCE WEDNESDAY NIGHT...A WEAK COLD FRONT
WILL DROP THROUGH WRN NEB IN THE MORNING ANGLED SW THROUGH KIML AND INTO
A SFC HEAT LOW ACROSS ERN COLO. THE FRONT WILL DRIFT SOUTH AND
EAST THROUGHOUT THE AFTERNOON. SOUTHWEST WINDS BELOW 700 MB WILL HAVE
EVACUATED WHATEVER MOISTURE WAS THERE AND THE DEPARTING UPPER
LEVEL DISTURBANCE WILL DRY OUT THE ATM ALOFT. THUS NO RAIN IS EXPECTED
THURSDAY EXCEPT PERHAPS ACROSS CNTL NEB DEPENDING ON THE LOCATION
OF THE FRONT.
A DEEP UPPER LEVEL DISTURBANCE WILL BE TRACKING THROUGH SRN
ALBERTA AND SRN SASKATCHEWAN FRIDAY. THIS SYSTEM SHOULD DRAW DEEPER
MOISTURE FROM TEXAS NORTH THROUGH WRN NEB DURING THE AFTERNOON AND
SUFFICIENT UPPER LEVEL FORCING SHOULD BE AVAILABLE FOR ISOLATED
STORM DEVELOPMENT FRIDAY AFTERNOON. A BROAD AREA OF STRATUS MAY DEVELOP
FRIDAY MORNING AS MOISTURE LIFTS NORTH. ALL SOLNS EXCEPT THE NAM12
SHOW THIS FORMING.
TEMPERATURES ARE EXPECTED TO RISE INTO THE 90S WEDNESDAY THROUGH
FRIDAY. VERTICAL MIXING PROFILES MAY BE LIMITED AS THE SFC LOW
WILL GENERALLY DROP DUE SOUTH THROUGH THE HIGH PLAINS VS TRACKING
EAST THROUGH SRN SD. SO MAX TEMPS FOLLOW A MIDDLE OF THE ROAD
APPROACH FOR A MIX OF HIGHS IN THE LOWER...MIDDLE AND A FEW UPPER 90S.
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY.
DECENT LOW AND MID LEVEL MOISTURE WILL SPREAD NORTH INTO THE AREA
FROM THE SOUTH FRIDAY NIGHT AHEAD OF A DECENT MID LEVEL DISTURBANCE.
850 MB DEW PTS PER THE ECMWF ARE PROGGED TO RISE TO NEAR 16C.
CHANCES FOR RAIN ARE EXPECTED TO INCREASE SATURDAY AS THE
DISTURBANCE MOVES ACROSS THE AREA...BUT RIGHT NOW MODELS INDICATING
THE BEST FOCUS FOR RAINFALL/CONVECTION MAY STAY SOUTH AND EAST OF
THE AREA. SO WON/T GET CARRIED AWAY WITH POPS...AND JUST CONTINUE
THE INHERITED 40 PERCENT CHANCES. SYSTEM MOVES EAST OF THE AREA
SUNDAY...WITH DRY WEATHER EXPECTED THE FIRST OF NEXT WEEK.
TEMPERATURE WISE...NEAR SEASONAL HIGHS IN THE 80S ARTE EXPECTED FOR
THE WEEKEND. BY EARLY NEXT WEEK HIGHS COULD REACH BACK INTO THE
LOWER 90S. LOWS WILL BE QUITE MILD WITH THE INCREASED
MOISTURE...WITH MOST AREAS STAYING IN THE 60S AT NIGHT.
FIRE WEATHER... BREEZY SOUTHERLY WINDS WILL INCREASE WEDNESDAY IN
RESPONSE TO A TIGHTENING PRESSURE GRADIENT ACROSS THE AREA. SOME
INCREASE IN LOW LEVEL MOISTURE IS EXPECTED...AND MINIMUM RELATIVE
HUMIDITY VALUES ARE EXPECTED TO REMAIN ABOVE 20 PERCENT. THE NAM
MODEL MAY BE DRYING OUT THE LOW LEVELS A LITTLE TOO MUCH ACROSS
CENTRAL NEBRASKA BASED ON WHAT IS OCCURRING TODAY...AND WILL FORGO
A FIRE WEATHER WATCH FOR THE THAT AREA AT THIS TIME.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1145 PM CDT TUE AUG 21 2012
.SHORT TERM...THROUGH THURSDAY NIGHT
230 PM CDT TUE AUG 21 2012
MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES WEDNESDAY THROUGH
THURSDAY NIGHT.
SURFACE ANALYSIS THIS AFTERNOON SHOWS HIGH PRESSURE CENTERED OVER
EASTERN IOWA INTO CENTRAL WISCONSIN.
THE FIRST CONCERN IS WHETHER ANY VALLEY FOG WILL FORM AGAIN
TONIGHT. THE SURFACE HIGH WILL BE PULLING OFF TO THE SOUTHEAST AND
SHOULD BE CENTERED OVER INDIANA BY LATE TONIGHT. BOTH THE 21.12Z
NAM AND GFS SUGGEST A WARM FRONT WILL DEVELOP IN THE RETURN FLOW
FROM SOUTH DAKOTA INTO MISSOURI. AS THIS OCCURS...BOTH MODELS
ACTUALLY SHOW A LITTLE BIT OF RIDGING DEVELOPING NORTH OF THE
FRONT AND OVER THE AREA. THIS SHOULD ALLOW THE SURFACE WINDS TO
DECOUPLE ONCE AGAIN AND DEW POINTS SHOULD RECOVER INTO THE UPPER
40S. SKIES WILL BE CLEAR OVERNIGHT SO PLENTY OF POSITIVES FOR THE
FOG. BOTH THE NAM AND 21.17Z RAP BUFKIT SOUNDING FOR KLSE SHOW
SOUTHWEST WINDS AROUND 20 KNOTS JUST ABOVE THE SURFACE UP THROUGH
ABOUT 3 OR 4 THOUSAND FEET. THIS IS VERY SIMILAR TO A COUPLE OF
NIGHTS AGO EXPECT THE WINDS ARE ABOUT 180 DEGREES DIFFERENT IN
DIRECTION AND MAYBE A LITTLE STRONGER TONIGHT. SOME FOG DID FORM
IN THESE SIMILAR CONDITIONS SATURDAY MORNING SO PLAN TO INCLUDE A
MENTION OF PATCHY FOG.
THE NEXT CONCERN IS WHETHER ANY RAIN WILL FORM WEDNESDAY AND
WEDNESDAY NIGHT IN THE RETURN FLOW. MODEL DIFFERENCES CONTINUE
WITH THE NAM AND GFS STILL SHOWING SOME RAIN DEVELOPING WHILE THE
21.00Z ECMWF REMAINS DRY. WHETHER THIS RAIN DEVELOPS OR NOT
DEPENDS ON HOW MUCH LOW LEVEL THERMODYNAMICS COME INTO PLAY. THE
NAM CONTINUES TO BE THE STRONGEST WITH THIS FORCING SHOWING WEAK
FRONTOGENESIS IN THE 1000-500 MB LAYER NORTH OF THE WARM FRONT.
THE ECMWF ALSO HAS A LITTLE BIT OF FRONTOGENESIS BUT ONLY UP
THROUGH 700 MB. THE BIG DIFFERENCE COMES IN THE ISENTROPIC
RESPONSE. THE NAM GENERATES UP TO 10 UBAR/S ON THE 310K SURFACE
WHILE THE GFS ONLY HAS ABOUT 3 UBAR/S AND THE ECMWF HAS BETWEEN 1
AND 2 UBAR/S. IF THIS RAIN DOES DEVELOP...THE NAM BUFKIT SOUNDINGS
SHOW CLOUD BASES WOULD BE ABOUT 10K FEET WITH LOTS OF DRY AIR
BELOW. WOULD NOT EXPECT MUCH MORE THAN SOME SPRINKLES OR A QUICK
SHOWER WITH A COUPLE HUNDREDTHS QPF.
THE MODEL DIFFERENCES CONTINUE INTO THURSDAY AND THURSDAY NIGHT AS
WELL. THE SHORT WAVE TROUGH COMING ONTO THE PACIFIC NORTHWEST
COAST TODAY WILL TOP THE ROCKIES AND START MOVING ACROSS THE UPPER
MIDWEST. THE ECMWF HAS BEEN VERY CONSISTENT SHOWING THE FILLING
UPPER LEVEL LOW WITH THIS SYSTEM TO BE MOVING NORTHEAST INTO
CENTRAL CANADA WHILE THE SHORT WAVE TROUGH COMES THROUGH WITH A
POSITIVE TILT. THE NAM AND GFS ARE SUGGESTING THAT A PIECE OF
ENERGY WILL BREAK OUT OF THE MEAN LONG WAVE TROUGH AXIS OR A NEW
SHORT WAVE TROUGH DEVELOPS IN THE LEE OF THE ROCKIES WEDNESDAY.
THESE MODELS THEN BRING THIS SHORT WAVE TROUGH ACROSS THE AREA
WITH A NEUTRAL TO NEGATIVE TILT AND QUICKER THAN THE POSITIVE
TILT OF THE ECMWF. AT THIS POINT...CONFIDENCE ON WHICH SOLUTION
WILL VERIFY IS NOT HIGH SO HAVE TRIED TO COMPROMISE BETWEEN THE
TWO WITH A SLIGHT NOD TOWARD THE ECMWF SOLUTION. WILL SHOW A SMALL
CHANCE OF RAIN ACROSS THE FAR NORTH THURSDAY MORNING AHEAD OF THE
ADVANCING WARM FRONT AND THEN 20 TO 30 PERCENT CHANCES DURING THE
AFTERNOON ACROSS THE WEST AND NORTH AS THE FORCING STARTS TO
INCREASE AHEAD OF THE APPROACHING SYSTEM. AS THE SHORT WAVE TROUGH
THEN COMES INTO LATER THURSDAY...IT SHOULD PRODUCE AROUND 4 PVU/S
OF VORTICITY ADVECTION IN THE 500-300 MB LAYER. NOT MUCH OF
SURFACE REFLECTION WITH THIS SYSTEM SO ONLY SOME WEAK
FRONTOGENESIS IN THE 1000-850 MB LAYER. SOME WEAK UP GLIDE OF 1-2
UBAR/S SHOULD CONTINUE ON THE 310K SURFACE ALONG WITH GETTING
INTO THE EASTERN AND CONVERGENT SIDE OF THE MOISTURE TRANSPORT
AXIS. ALL THIS FORCING LOOKS TO BE AT ITS STRONGEST THURSDAY NIGHT
ACROSS THE NORTH AND DID INCREASE THE RAIN CHANCE TO AROUND 60
THERE.
.LONG TERM...FRIDAY THROUGH TUESDAY
230 PM CDT TUE AUG 21 2012
THE RAIN THAT DEVELOPS THURSDAY/THURSDAY NIGHT SHOULD BE COMING TO
AN END FRIDAY INTO FRIDAY NIGHT AS THE SHORT WAVE TROUGH MOVES
PAST THE AREA. THE NEXT PIECE OF ENERGY WILL QUICKLY APPROACH FROM
THE WEST COAST WITH THE UPPER LEVEL LOW AGAIN MOVING ACROSS CANADA
ALLOWING A SOUTHWEST FLOW ALOFT TO DEVELOP ACROSS THE UPPER
MIDWEST. INITIALLY THE MODELS ARE IN GOOD AGREEMENT THAT A SHORT
WAVE TROUGH WILL BE IN THIS SOUTHWEST FLOW OVER THE MID PLAINS
STATES SATURDAY NIGHT BUT THEN DIVERGE AS THEY START TO LIFT THIS
WAVE NORTHEAST. THE GFS FLATTENS THIS WAVE OUT AND LIFTS IT
THROUGH QUICKER THAN EITHER THE 21.12Z GEM OR ECMWF. THE ECMWF IS
THE STRONGEST AND SLOWEST LIFTING THIS WAVE TO THE NORTHEAST. THE
DIFFERENCES COULD BE STEMMING FROM THE WIDE RANGE OF SOLUTIONS
THAT ARE SHOWING UP WITH A POTENTIAL TROPICAL SYSTEM APPROACHING
THE SOUTHEAST U.S. AND FOR NOW HAVE STAYED WITH THE MODEL
CONSENSUS GRIDS WITH 30 TO 50 PERCENT RAIN CHANCES SATURDAY NIGHT
THROUGH SUNDAY NIGHT WITH THE SYSTEM THEN MOVING PAST MONDAY.
&&
.AVIATION...THROUGH 06Z THURSDAY
1144 PM CDT TUE AUG 21 2012
MAIN CONCERN REMAINS VALLEY FOG POTENTIAL AT KLSE THIS MORNING.
A WEAK PRESSURE GRADIENT RESULTING FROM HIGH PRESSURE CENTERED
NEAR CHICAGO KEPT WINDS FAIRLY LIGHT LAST EVENING. HOWEVER...THE
HIGH CONTINUES TO DRIFT OFF TO THE EAST...WHICH IN TURN WILL
INCREASE WINDS ABOVE THE SURFACE. THE WIND INCREASE IS ALREADY
BEING FELT AT THE OFFICE HERE ON TOP OF THE BLUFF. THESE WINDS IN
CONJUNCTION WITH DRY AIR IN PLACE AND LACK OF RECENT PRECIPITATION
SHOULD HELP MINIMIZE VALLEY FOG OR STRATUS FROM DEVELOPING. STILL
DO NOT HAVE CONFIDENCE OF COMPLETELY PULLING VCFG OR SCATTERED
LIFR CLOUDS BETWEEN THE 11-14Z TIME PERIOD...GIVEN COOLING AND
SOME MOISTENING THAT HAS OCCURRED. HOWEVER...IT SEEMS THAT VFR
CONDITIONS ARE FAIRLY CERTAIN.
OTHERWISE...SOUTHERLY FLOW WILL CONTINUE TO INCREASE TODAY AS A
WARM FRONT LIFTS FROM NEBRASKA TO THE TAF SITES. GUSTS AT KRST
COULD TOP OUT AROUND 18 KT OR SO DURING THE AFTERNOON WITH DAYTIME
MIXING. ALTOSTRATUS DEVELOPMENT IS LIKELY AS WELL AS THE FRONT
APPROACHES. IT APPEARS ANY PRECIPITATION OUT OF THIS CLOUD DECK
WOULD BE SPRINKLES AT BEST...NOT ENOUGH TO MENTION IN THE TAF.
ONE LAST ITEM TO WATCH IS POTENTIAL FOR LOW LEVEL WIND SHEAR AT
KLSE APPROACHING 06Z THURSDAY AS THE WARM FRONT LIFTS NORTH OF THE
TAF SITES. THERE ARE SOME SUGGESTIONS OF A 30 KT SOUTHWEST LOW
LEVEL JET DEVELOPING AT 1000 FT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
230 PM CDT TUE AUG 21 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS GOODLAND KS
503 AM MDT WED AUG 22 2012
.UPDATE...
ISSUED AT 412 AM MDT WED AUG 22 2012
NOSE OF HIGHER BOUNDARY LAYER RH REACHING TRIBUNE AREA WHERE
VISIBILITY AT 5SM. THIS AXIS OF HIGHER MOISTURE WITH PATCHY FOG
EXPECTED PER RUC TO MOVE SLOWLY NORTHEASTWARD THROUGH SUNRISE
BEFORE RETREATING BACK TO THE SOUTHWEST AFTER SUNRISE. HAVE GONE
AHEAD AND ADDED PATCHY FOG TO IMPACTED AREAS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 215 AM MDT WED AUG 22 2012
A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE ACROSS THE FORECAST
AREA THROUGH THE PERIOD AHEAD OF A LOW PRESSURE CENTER WHICH
SHOULD REACH THE AREA LATE FRIDAY THROUGH FRIDAY NIGHT. TIMING OF
THE DISTURBANCES AND THE LOW ITSELF REMAIN IN QUESTION BUT TYPICAL
AFTERNOON AND EVENING THUNDERSTORMS ARE POSSIBLE.
HIGH TEMPERATURES TODAY IN THE LOW TO MID 90S. SLIGHTLY COOLER
THURSDAY WITH MID 80S TO NEAR 90 IN EASTERN COLORADO...LOW 90S
ELSEWHERE. ON FRIDAY A BIT COOLER UNDER CLOUDINESS WITH MID TO
UPPER 80S.
SOUTH WINDS TODAY GENERALLY 15 TO 20 MPH WITH GUSTS TO 30 MPH
POSSIBLE ALONG/EAST OF THE CO/KS BORDER. SIMILAR WINDS THURSDAY
BUT SLIGHTLY FURTHER EAST CLOSER TO THE GOVE...LEOTI AND HILL CITY
AREAS.
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 215 AM MDT WED AUG 22 2012
A SHORTWAVE TROUGH WILL COME THROUGH ON SATURDAY AND PROVIDE AMPLE
FORCING FOR A CHANCE OF SHOWERS AND THUNDERSTORMS. FOLLOWING THIS
TROUGH AN UPPER LEVEL RIDGE WILL BUILD IN OVER THE ROCKIES AND
PERSIST THROUGH MID-WEEK. A FEW WEAK SHORTWAVES PASS THROUGH EARLY
IN THE WEEK...BUT AT THIS POINT IT DOES NOT LOOK LIKE THERE WILL
BE ENOUGH MOISTURE OR FORCING TO TRIGGER STORMS. TEMPERATURES OVER
THE PERIOD LOOK TO BE NEAR NORMAL WITH AFTERNOON HIGHS IN THE MID
80S TO UPPER 90S...AND OVERNIGHT LOWS IN THE LOWER TO MID 60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 503 AM MDT WED AUG 22 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD AT BOTH KGLD AND
KMCK. SOUTHERLY WINDS WILL INCREASE LATE THIS MORNING WITH GUSTS
APPROACHING 30 KTS DURING THE AFTERNOON. LATE IN THE DAY A FEW
THUNDERSTORMS MAY DEVELOP OVER EASTERN COLORADO AND APPROACH BOTH
TERMINALS BY EARLY EVENING...WITH MORE CONFIDENCE THAT STORMS
WOULD REACH GLD THAN MCK. WHILE THE DYNAMICS FOR STORMS IS
THERE...THE MOISTURE PROFILE IS MARGINAL...SO HAVE OPTED TO LEAVE
OUT ANY MENTION OF STORMS AT THIS TIME.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...99
LONG TERM...JJM
AVIATION...99/JJM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
415 AM MDT WED AUG 22 2012
.UPDATE...
ISSUED AT 412 AM MDT WED AUG 22 2012
NOSE OF HIGHER BOUNDARY LAYER RH REACHING TRIBUNE AREA WHERE
VISIBILITY AT 5SM. THIS AXIS OF HIGHER MOISTURE WITH PATCHY FOG
EXPECTED PER RUC TO MOVE SLOWLY NORTHEASTWARD THROUGH SUNRISE
BEFORE RETREATING BACK TO THE SOUTHWEST AFTER SUNRISE. HAVE GONE
AHEAD AND ADDED PATCHY FOG TO IMPACTED AREAS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 215 AM MDT WED AUG 22 2012
A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE ACROSS THE FORECAST
AREA THROUGH THE PERIOD AHEAD OF A LOW PRESSURE CENTER WHICH
SHOULD REACH THE AREA LATE FRIDAY THROUGH FRIDAY NIGHT. TIMING OF
THE DISTURBANCES AND THE LOW ITSELF REMAIN IN QUESTION BUT TYPICAL
AFTERNOON AND EVENING THUNDERSTORMS ARE POSSIBLE.
HIGH TEMPERATURES TODAY IN THE LOW TO MID 90S. SLIGHTLY COOLER
THURSDAY WITH MID 80S TO NEAR 90 IN EASTERN COLORADO...LOW 90S
ELSEWHERE. ON FRIDAY A BIT COOLER UNDER CLOUDINESS WITH MID TO
UPPER 80S.
SOUTH WINDS TODAY GENERALLY 15 TO 20 MPH WITH GUSTS TO 30 MPH
POSSIBLE ALONG/EAST OF THE CO/KS BORDER. SIMILAR WINDS THURSDAY
BUT SLIGHTLY FURTHER EAST CLOSER TO THE GOVE...LEOTI AND HILL CITY
AREAS.
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 215 AM MDT WED AUG 22 2012
A SHORTWAVE TROUGH WILL COME THROUGH ON SATURDAY AND PROVIDE AMPLE
FORCING FOR A CHANCE OF SHOWERS AND THUNDERSTORMS. FOLLOWING THIS
TROUGH AN UPPER LEVEL RIDGE WILL BUILD IN OVER THE ROCKIES AND
PERSIST THROUGH MID-WEEK. A FEW WEAK SHORTWAVES PASS THROUGH EARLY
IN THE WEEK...BUT AT THIS POINT IT DOES NOT LOOK LIKE THERE WILL
BE ENOUGH MOISTURE OR FORCING TO TRIGGER STORMS. TEMPERATURES OVER
THE PERIOD LOOK TO BE NEAR NORMAL WITH AFTERNOON HIGHS IN THE MID
80S TO UPPER 90S...AND OVERNIGHT LOWS IN THE LOWER TO MID 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1126 PM MDT TUE AUG 21 2012
LIGHT SOUTHERLY WINDS AND VFR CIGS AND VIS EXPECTED OVERNIGHT
TONIGHT. THE SOUTHERLY WINDS WILL INCREASE IN SPEED BY MID
MORNING TOMORROW WITH GUSTS APPROACHING 30 KTS BY THE AFTERNOON.
LATE IN THE DAY TOMORROW THUNDERSTORMS SHOULD DEVELOP IN EASTERN
COLORADO WHICH MAY APPROACH BOTH TERMINALS TOMORROW EVENING BUT
CONFIDENCE IN TIMING AND AREAL COVERAGE IS TOO LOW THIS FAR OUT IN
TIME TO INTRODUCE IN THE TAFS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...99
LONG TERM...JJM
AVIATION...05
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1102 AM EDT WED AUG 22 2012
.SYNOPSIS...
UPPER LEVEL LOW PRESSURE WILL MOVE EASTWARD PAST THE MOUNTAINS BY
THIS EVENING LEAVING THE UPPER OHIO VALLEY DRY AND POSSIBLY
GIVING A SHOWER OR ISOLATED THUNDERSTORM OVER THE RIDGES THIS
AFTERNOON. HIGH PRESSURE WILL FOLLOW WITH DRY CONDITIONS THROUGH
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RECENT VISIBLE SATELLITE AND SURFACE DATA SHOW THE FOG HAS DISSIPATED
AND HAS GIVEN WAY TO A CLEAR SKY WITH THE EXCEPTION OF A FEW
CLOUDS OVER THE EXTREME SOUTHEAST FA.
WATER VAPOR IMAGERY SHOWS UPPER LOW LEVEL PRESSURE TROUGH MOVING
EASTWARD THROUGH SOUTHWEST PENNSYLVANIA AND CURRENT MESOSCALE
ANALYSIS SHOWS COLDEST AIR AT 500MB OF -16C SHIFTING EAST INTO
CENTRAL PA AND SHOULD EXIT PAST THE MOUNTAINS BEFORE EVENING. SO
ONLY LEFT A CHANCE OF AFTERNOON ISOLATED THUNDERSTORMS FOR THE
MOUNTAINS, WHERE CONVECTIVE TEMPERATURES SHOULD HAVE TO REACH THE
MID 70S BEFORE ANY SHOWERS OR THUNDERSTORMS FORM, WHICH IS
SUPPORTED BY RECENT HRRR MODEL OUTPUT.
OTHERWISE, PLENTY OF SUNSHINE TODAY WITH FORECASTED HIGHS USING
GFS/NAM BLEND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
HEIGHTS WILL BEGIN TO SLOWLY RISE THU, AND A WEAK RIDGE WILL
BUILD IN OVER THE UPPER OHIO VALLEY THROUGH FRIDAY. AT THE SFC,
WEAK SFC HIGH WILL VERY SLOWLY MOVE ACROSS THE REGION THROUGH THE
END OF THE WORK WEEK. DAYTIME TEMPS WILL RISE A BIT DURING THE
SHORT TERM.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH THE WEEKEND, WITH SFC HIGH
AND UL RIDGE HOLDING OVER THE OHIO VALLEY. MODEL SOLUTIONS BEGIN
TO DISPERSE EARLY NEXT WEEK. BECAUSE OF LOW CONFIDENCE AND
INCONSISTENCY FROM RUN TO RUN, WILL MAKE VERY FEW CHANGES TO LONG
TERM PERIOD.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
VFR WEATHER CAN BE EXPECTED INTO TONIGHT AS HIGH PRES BLDS OVR THE
UPR OH VALLEY REGION. EXPECT RIVER VALLEY FOG TO DVLP ONCE AGAIN IN
THE PREDAWN OF THURSDAY MORNING...WHICH MAY CAUSE A BRIEF PERIOD OF
IFR.
.OUTLOOK/ THURSDAY THROUGH SUNDAY/...
VFR PREDOMINATE...EXCEPT FOR POSSIBLE RESTRICTIONS DUE TO EARLY
MORNING RIVER VALLEY FOG.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
808 AM EDT WED AUG 22 2012
.SYNOPSIS...
UPPER LEVEL LOW PRESSURE WILL MOVE EASTWARD PAST THE MOUNTAINS BY
EVENING. SO MOST OF THE UPPER OHIO VALLEY WILL SEE NO RAIN, WHILE A
SHOWER OR STORM IS POSSIBLE OVER THE RIDGES THIS AFTERNOON.
HIGH PRESSURE WILL FOLLOW WITH DRY CONDITIONS THROUGH THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RECENT SATELLITE AND SURFACE DATA SHOW THE FOG MAINLY CONFINED TO
RIVER VALLEYS, SO EXPECT THE FOG TO DISSIPATE BEFORE 10 AM.
SATELLITE DATA SHOWS UPPER LOW LEVEL PRESSURE TROUGH MOVING
EASTWARD THROUGH SOUTHWEST PENNSYLVANIA, AND SHOULD EXIT PAST THE
MOUNTAINS BEFORE EVENING. SO ONLY LEFT A CHANCE OF AFTERNOON
THUNDERSTORMS FOR THE MOUNTAINS, WHERE CONVECTIVE TEMPERATURES
SHOULD HAVE TO REACH THE MID 70S BEFORE ANY SHOWERS OR THUNDERSTORMS
FORM, WHICH IS SUPPORTED BY RECENT HRRR MODEL OUTPUT.
OTHERWISE, PLENTY OF SUNSHINE TODAY WITH FORECASTED HIGHS CLOSER
TO GFS MOS VALUES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
HEIGHTS WILL BEGIN TO SLOWLY RISE THU, AND A WEAK RIDGE WILL
BUILD IN OVER THE UPPER OHIO VALLEY THROUGH FRIDAY. AT THE SFC,
WEAK SFC HIGH WILL VERY SLOWLY MOVE ACROSS THE REGION THROUGH THE
END OF THE WORK WEEK. DAYTIME TEMPS WILL RISE A BIT DURING THE
SHORT TERM.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH THE WEEKEND, WITH SFC HIGH
AND UL RIDGE HOLDING OVER THE OHIO VALLEY. MODEL SOLUTIONS BEGIN
TO DISPERSE EARLY NEXT WEEK. BECAUSE OF LOW CONFIDENCE AND
INCONSISTENCY FROM RUN TO RUN, WILL MAKE VERY FEW CHANGES TO LONG
TERM PERIOD.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
REMAINING IFR RIVER VALLEY FOG WILL DISSIPATE BEFORE 14Z. EXPECT
VFR THE REST OF TODAY AND EARLY TONIGHT.
EXPECT RIVER VALLEY FOG TO DEVELOP AGAIN EARLY THURSDAY MORNING,
WHICH CAUSE A PERIOD OF MVFR FOG AND STRATUS AT MOST TAF SITES
09Z-13Z, AND PERHAPS A SHORT PERIOD OF IFR.
.OUTLOOK/ THURSDAY THROUGH SUNDAY/...
MAINLY VFR, EXCEPT FOR POSSIBLE RESTRICTIONS DUE TO EARLY MORNING
RIVER VALLEY FOG.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
655 AM CDT WED AUG 22 2012
.DISCUSSION...
12Z TAF BULLETIN RATIONAL BELOW.
&&
.AVIATION...
UPPER TROUGH LOCATED JUST OVER NW GULF OF MEXICO THIS MORNING WITH
DRY SUBSIDENT AIR SEEN BEHIND IT OVER MUCH OF SE TX ON WV IMAGERY.
IR SATELLITE LOOPS AND METARS SHOW MID LAYER CIG FL080-100 ACROSS
MOST OF THE TAF SITES THIS MORNING. DIFFUSE STATIONARY FRONT
DRAPED ACROSS SE TX ALONG WITH OUTFLOW BOUNDARIES GALORE FROM
OFFSHORE AND NEARSHORE CONVECTION THIS MORNING. LOOKS FAIRLY QUIET
AT KGLS AND KLBX THE NEXT COUPLE OF HOURS WITH VCSH/VCTS GRADUALLY
MAKING ITS WAY INLAND WITH SEA BREEZE/OUTFLOW BOUNDARIES. UPPER
DRYING SHOULD GRADUALLY ERODE MIDLEVEL CIGS BY LATE MORNING PER
FCST SOUNDINGS. HGX WRF-ARW AND HRRR REFLECTIVITY FORECASTS AGREE
WITH SCATTERED CONVECTION FORMING ALONG THESE BOUNDARIES TODAY AND
HAVE SO FAR PERFORMED DECENTLY THIS MORNING. LOOKS LIKE THIS
ACTIVITY MAY SPREAD AS FAR NORTH AS THE SOUTH PART OF THE TAF
VCNTY DONUT FOR KCXO BY MID-AFTN. WITH LOSS OF HEATING ACTIVITY
SHOULD DIMINISH BY LATE AFTERNOON/EARLY EVENING. GIVEN THE
COMPETING FACTORS FOR AND AGAINST CONVECTION WOULD EXPECT SCT
COVERAGE. SOME INDICATION IN FORECAST SOUNDINGS AND NAM/GFS MOS
GUIDANCE FOR SOME MVFR FOG AT RURAL KCXO AND KLBX SITES TOWARDS
SUNRISE. ADDITIONAL OFFSHORE SHRA/TS IS FORECAST TOMORROW MORNING
SO HAVE INCLUDED VCSH AT KGLS. 04
&&
.PREV DISCUSSION... /ISSUED 459 AM CDT WED AUG 22 2012/
DISCUSSION...
NORTHWESTERLY FLOW ALOFT WILL CONTINUE TO AFFECT SE TX THROUGH THE
END OF THE WEEK...WITH A WEAKNESS IN THE RIDGE JUST EAST OF THE
STATE. A WEAK SURFACE BOUNDARY WAS PRESENT ACROSS GALVESTON BAY
EASTWARD INTO THE GULF EARLY THIS MORNING...WITH DEEP LAYER
MOISTURE PRESENT JUST TO THE SOUTH. THE SURFACE FEATURE WILL BE
THE FOCUS FOR SHOWERS AND THUNDERSTORMS THIS MORNING. LATER
TODAY...A SHORTWAVE TROUGH MOVING THROUGH THE FLOW ALOFT WILL HELP
GENERATE MORE CONVECTIVE ACTIVITY AT LEAST OVER THE SOUTHERN HALF
OF THE FORECAST AREA AS THE MOISTURE STREAMS NORTHWARD OVER THE
SURFACE BOUNDARY AND ANY SEABREEZE THAT DEVELOPS. THE SAME GENERAL
SCENARIO LOOKS TO OCCUR ON THURSDAY...AND THEN AGAIN ON FRIDAY.
THE CLOUD COVER EACH DAY WILL GENERALLY KEEP THE AFTERNOON
TEMPERATURES IN THE LOWER 90S AT MOST INLAND SITES AWAY FROM THE
COAST.
THE MODELS BEGIN TO DIFFER OVER THE WEEKEND...WITH THE GFS AND
ECMWF PATTERNS NOT IN VERY GOOD AGREEMENT DURING THE FIRST HALF OF
NEXT WEEK. GIVEN THE LARGE UNCERTAINTY AND LOW CONFIDENCE IN BOTH
MODELS...FELT THAT THE BEST SOLUTION WAS TO STAY WITH ISOLATED
CHANCES MAINLY DURING THE DAYTIME DUE TO SEABREEZE ACTIVITY.
40
MARINE...
COUPLE OF BOUNDARIES EVIDENT ON RADAR LOOPS...ONE STRETCHING FROM
ANGLETON TO ABOUT 15 MILES OFFSHORE OF THE BOLIVAR PENINSULA AT
09Z THIS MORNING. MOSTLY SHOWERS BUT OCCASIONALLY SOME CG LTG
BEING DETECTED. BOUNDARY IS DRIFTING SLOWLY INLAND WITH MEAN LOW
LEVEL FLOW. SECOND BOUNDARY JUST BEGINNING TO SHOW UP AROUND 20-25
NMI OFFSHORE ROUGHLY PARALLEL TO COAST. THESE BOUNDARIES SHOULD
COMBINE WITH UPPER TROUGH/DIFFLUENCE TO PRODUCE A GOOD CHANCE FOR
SHOWERS AND STORMS FOR NEARSHORE/BAY/OFFSHORE WATERS TODAY
ESPECIALLY THIS MORNING. SIG WAVE HGTS SHOULD REMAIN IN THE 1 TO 3
FOOT RANGE THE NEXT SEVERAL DAYS WITH ONSHORE FLOW. SOME
DIURNAL/LATE NIGHT INCREASE IN WIND SPEEDS POSSIBLE THU NGT/FRI
MORNING MAY INCREASE SOME WAVE HGT TO AROUND 4 FT.
04
AVIATION...
SHORT TERM UPDATES FOR OBSERVED SHRA/TSRA TRENDS WITH BOUNDARY
NEAR COASTAL TAF SITES...KGLS AND KLBX THIS MORNING. EARLY
INDICATIONS FOR PCPN CHANCES SUGGEST LEAVING OUT OF TAFS NORTH OF
THE METRO AREA. WILL EVALUATE NEED FOR VCSH/VCTS GROUPS FOR KIAH
AND KHOU FOR THE 12Z TAF PACKAGE.
04
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 92 72 92 74 91 / 10 10 10 10 20
HOUSTON (IAH) 90 73 92 75 90 / 30 10 30 20 40
GALVESTON (GLS) 89 80 91 81 90 / 30 20 40 20 40
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
625 AM CDT WED AUG 22 2012
.SHORT TERM...TODAY THROUGH FRIDAY
314 AM CDT WED AUG 22 2012
MAIN FORECAST CONCERNS ARE ON SLIGHT SHOWER AND THUNDERSTORM CHANCES
TODAY...FOCUS THEN TURNS TO RAIN CHANCES AND TEMPERATURES THURSDAY
INTO FRIDAY.
LATEST WATER VAPOR IMAGERY SHOWS NORTHWEST FLOW ALOFT ACROSS THE
FORECAST AREA WITH AN UPPER LEVEL TROUGH PUSHING INTO IDAHO AND
WESTERN MONTANA. SURFACE OBSERVATIONS INDICATED A SURFACE LOW OVER
SOUTHEAST SOUTH DAKOTA WITH A WARM FRONT EXTENDING SOUTHEAST THROUGH
SOUTHWEST IOWA...LIFTING NORTHWARD.
THE WARM FRONT IS EXPECTED TO LIFT FROM SOUTH TO NORTH ACROSS THE
FORECAST AREA TODAY INTO THIS EVENING. A WEAK SHORTWAVE WILL PUSH
ACROSS THE REGION AND INTERACT WITH THE BOUNDARY POSSIBLY GENERATING
ISOLATED SHOWERS AND THUNDERSTORM. ISOLATED SHOWERS AND
THUNDERSTORMS WILL BE ONGOING ACROSS PORTIONS OF SOUTH CENTRAL
MINNESOTA THIS MORNING...POSSIBLY EDGING INTO SOUTHEAST MINNESOTA.
SHOULD SEE THIS ACTIVITY TAPER OFF AS MOISTURE TRANSPORT WEAKENS.
OVERALL THE LOWER LEVELS OF THE ATMOSPHERE ARE VERY DRY WITH
INVERTED V TYPE SOUNDINGS AND CLOUD BASES AT 10 KFT. WILL BE
INCLUDING A CHANCE OF SHOWERS AND THUNDERSTORM FOR THIS MORNING
ACROSS PORTIONS OF NORTHEAST IOWA INTO SOUTHEAST MINNESOTA. SLIGHT
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL EXPAND NORTHEAST THIS
AFTERNOON INTO EARLY THIS EVENING INTO PORTIONS OF SOUTHWEST INTO
CENTRAL WISCONSIN.
THE WARM FRONT IS EXPECTED TO LIFT NORTH OF THE INTERSTATE 94
CORRIDOR LATE THIS EVENING WITH ANY LINGERING ISOLATED SHOWER AND
THUNDERSTORM CHANCES GRADUALLY LIFTING TO THE NORTH. FORECAST MODELS
ARE IN AGREEMENT SHOWING THE WARM FRONT LIFTING INTO FAR NORTHERN
WISCONSIN...PLACING THE FORECAST AREA IN THE WARM SECTOR THROUGH
MUCH OF THE DAY ON THURSDAY. RATHER DRY AIR IS EXPECTED TO MOVE INTO
THE REGION WITHIN THE WARM SECTOR AND WITH AFTERNOON MIXING WILL SEE
DEW POINTS PLUMMET INTO THE 40S. FORECAST SOUNDINGS SHOW DEEP MIXING
SO SHOULD SEE TEMPERATURES WARM WELL INTO THE 80S...WITH LOWER 90S
EXPECTED ALONG AND SOUTH OF THE INTERSTATE 90 CORRIDOR. HAVE WARMED
HIGHS A FEW DEGREES FOR THURSDAY AND DROPPED DEW POINTS
SIGNIFICANTLY. IN ADDITION...THURSDAY WILL BE BREEZY WITH A TIGHT
PRESSURE GRADIENT OVER THE AREA...WITH SOUTH/SOUTHWEST WINDS AT 10
TO 20 MPH WITH GUSTS AROUND 30 MPH IN THE OPEN AREAS. WILL HAVE
TO CLOSELY MONITOR CLOUD TRENDS IN THE FORECAST MODELS THE NEXT
SET OF RUNS WITH THE POTENTIAL FOR MID AND HIGH CLOUDS TO LINGER
THROUGH EARLY AFTERNOON. THE WINDS AND FALLING DEW POINTS COULD
CREATE FIRE WEATHER CONCERNS THURSDAY AFTERNOON...BEFORE CLOUDS
SPILL IN LATE IN THE AFTERNOON FROM A TROUGH APPROACHING FROM
WESTERN MINNESOTA.
22.00 FORECAST MODELS HAVE REALLY SLOWED THE ARRIVAL OF
PRECIPITATION THURSDAY INTO FRIDAY. THE TROUGH WILL MOVE SLOWLY
ACROSS MINNESOTA THROUGH THE DAY ON THURSDAY PUSHING ACROSS THE
MISSISSIPPI RIVER LATE THURSDAY NIGHT INTO FRIDAY MORNING. HAVE
CONTINUED THE TREND OF SLOWING THE ARRIVAL OF SHOWERS AND
THUNDERSTORMS UNTIL LATE THURSDAY AFTERNOON INTO THURSDAY
EVENING...WITH THE BULK OF THE ACTIVITY IMPACTING LOCATIONS ALONG
AND WEST OF THE MISSISSIPPI RIVER IN THE LATE EVENING INTO EARLY
FRIDAY MORNING. HAVE INCREASED PRECIPITATION CHANCES LATE THURSDAY
NIGHT INTO EARLY FRIDAY MORNING WHEN THE STRONGEST MOISTURE
TRANSPORT IS FOCUSED INTO THE AREA...ESPECIALLY AT THE 850 MB
LEVEL. THE TROUGH WILL SHIFT EAST OF THE REGION FRIDAY AFTERNOON
WITH SHOWERS AND THUNDERSTORMS TAPERING OFF. WARM SOUTHERLY FLOW
WILL CONTINUE ACROSS THE AREA FRIDAY AFTERNOON INTO FRIDAY NIGHT.
TWO PIECES OF ENERGY TO KEEP A CLOSE WATCH ON FRIDAY NIGHT INTO
SATURDAY. THE FIRST IS A POTENT TROUGH MOVING ALONG THE U.S. CANADA
BORDER...JUST BRUSHING NORTHERN MONTANA AND NORTH DAKOTA PUSHING
EAST. THE SECOND FEATURE IS A TROUGH MOVING OUT OF THE CENTRAL
PLAINS HEADING TOWARD THE MIDDLE MISSISSIPPI RIVER VALLEY.
.LONG TERM...SATURDAY THROUGH TUESDAY
314 AM CDT WED AUG 22 2012
22.00 MODELS STRUGGLING A BIT ON HANDLING THE TROUGH MOVING ALONG
THE U.S. CANADA BORDER AND THE WAVE PUSHING ACROSS THE CENTRAL
PLAINS. THE ECMWF KEEPS THESE TWO FEATURES SEPARATE LIFTING THE
NORTHERN STREAM TROUGH NORTH OVER HUDSONS BAY SATURDAY INTO
SUNDAY...WITH THE SOUTHERN TROUGH IMPACTING THE MIDDLE MISSISSIPPI
RIVE VALLEY REGION. THE GFS ATTEMPTS TO PHASE THESE TWO FEATURES
WHICH WOULD FAVOR HIGHER PRECIPITATION CHANCES ACROSS THE AREA.
GIVEN THE FORECAST MODEL DIFFERENCES WILL LEAN TOWARD A MODEL
CONSENSUS BLEND THROUGH THE WEEKEND...WITH SHOWER AND
THUNDERSTORMS CHANCES SATURDAY NIGHT INTO SUNDAY. A BROAD UPPER
RIDGE LOOKS TO BUILD INTO THE WESTERN CONUS BY EARLY NEXT WEEK
PROVIDING DRY CONDITIONS AND SEASONABLE TEMPERATURES ACROSS THE
FORECAST AREA.
&&
.AVIATION...
625 AM CDT WED AUG 22 2012
WINDS AND DRY AIR HAVE CONSPIRED TO PUT THE BRAKES ON RIVER VALLEY
FOG FORMATION THIS MORNING. BUFKIT RAP SOUNDING POINTS TO 15 KTS OF
WIND BY 200 FT...WHILE THE 00Z T/TD SPREAD WAS 32 F. BOTH ARE
UNFAVORABLE FOR DENSE FOG. A GOOD AMOUNT OF BREEZE AT THE ARX OFFICE
ON THE BLUFF OVERLOOKING THE LA CROSSE VALLEY TOO...AND NO STRATUS
EVIDENT ON THE RIVER. SO...WILL STAY WITH P6SM AT KLSE.
OFF TO THE WEST LOW LEVEL WARM AIR ADVECTION AND THE LOW LEVEL
JET/MOISTURE TRANSPORT WERE HELPING SPARK A FEW SHRA/TS OVER
SOUTHWEST/SOUTHERN MN. THE JET AND MOISTURE TRANSPORT WILL WEAKEN
THIS MORNING...BUT THE WARM AIR ADVECTION LINGERS...AS WILL SOME
FRONTOGENETIC FORCING. IN ADDITION...SOME ELEVATED INSTABILITY WILL
BUILD FOR THE AFTERNOON. ITS WEAK DYNAMICALLY...BUT THERE HAS BEEN
ENOUGH TO DRIVE THE CURRENT PCPN...AND EXPECT ENOUGH TO CONTINUE
ISOLD/SCT THREAT INTO THIS EVENING. THE SATURATION IS A LOFT...AND
MOST BASES WILL BE CONFINED FROM 8 TO 12 KFT. WITH THE MORE MISS
THAN HIT ASPECT TO THE SHRA/TS...HAVE OPTED TO LEAVE OUT OF THE TAFS
FOR NOW.
WINDS WILL BECOME MORE SOUTHERLY TODAY...AND START TO INCREASE ON
THURSDAY AS THE PRESSURE GRADIENT TIGHTENS AHEAD OF AN APPROACHING
COLD FRONT. DEEP MIXING UP TO 750 MB AND UNIDIRECTIONAL WINDS A LOFT
SHOULD LEAD TO WIND GUSTS AROUND 25 MPH AT KRST THU AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
314 AM CDT WED AUG 22 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
300 PM CDT WED AUG 22 2012
.DISCUSSION...
NO OBVIOUS FOR ISOLATED STORM DEVELOPMENT SHOWING ON RADAR OR VSBY
SATELLITE. WATER VAPOR AND THE RAP MODEL INDICATE A MID LEVEL DISTURBANCE
NEAR KSLC. THIS DISTURBANCE IS PROGGED BY ALL MODELS TO BEGIN
AFFECTING THE FCST AREA THURSDAY AFTERNOON SO RAIN CHANCES THIS
EVENING...ALBEIT ISOLATED...LOOK UNCERTAIN AT THIS TIME. NOTE THAT
THE RAP IS POOLING CONSIDERABLE MOISTURE ACROSS SWRN LATE TONIGHT.
THE COULD RAISE THE PROSPECT OF STRATUS BUT NON IS INDICATED BY 12Z
AT KMCK.
THUS THE FCST TURNS TO THURSDAY AFTERNOON. THE NAM AND GEM BRING
A WEAK COLD FRONT THROUGH THE FCST AREA OVERNIGHT. NEITHER THE GFS
NOR THE ECM SHOW THIS FEATURE. THEY INSTEAD WASH THE FRONT OUT
NEAR THE SOUTH DAKOTA BORDER AND MAINTAIN A BELT OF STRONG
SOUTHWEST WINDS FARTHER WEST DURING THE DAY THURSDAY. BY THIS TIME
THE DISTURBANCE CURRENTLY ACROSS NRN UT SHOULD BE OPERATING ACROSS
KS AND SRN NEB. ALL MODELS SUGGEST A HEAVY RAIN CENTER WILL
DEVELOP THURSDAY NIGHT THROUGH FRIDAY...SOMEWHERE ACROSS KS. THE
NAM WAS THE FARTHEST NORTH PRODUCING 1.8 INCHES NEAR NORTON KS.
THE 12Z GFS INDICATED 11 INCHES OVER KHLC. THE ECM AROUND 2.5 NEAR
KP28 AND THE SREF HAD 1.35 NEAR KGLD. ALL OF THESE SOLNS WERE
BLENDED TOGETHER TO PRODUCE CHC POPS ACROSS SWRN AND SCNTL NEB. BY
FRIDAY MORNING MOST SOLNS SHOW A CLOSE 500 MB LOW FORMING OVER KS
AND IT APPEARS THE MODELS ARE TAKING PIECES OF THE DEEP SWRN U.S.
UPPER LEVEL LOW ACROSS THE ROCKIES AND RECONSOLIDATING IT OVER
KS.
SO THE FCST FOLLOWS THESE SOLNS AND PARTS OF THE FCST AREA WILL BE
ON THE PERIPHERY OF WHAT COULD BECOME A LARGE COMPLEX OF SHOWERS
AND THUNDERSTORMS LATE THURSDAY THROUGH FRIDAY. A POWERFUL NRN
STREAM DISTURBANCE WILL TRACK ALONG THE CANADIAN BORDER FRIDAY
NIGHT AND SATURDAY AND THIS SHOULD OPEN UP THE CLOSED KS LOW AND
SHEAR IT OUT TO THE EAST SOMETIME DURING THE DAY SATURDAY.. A
SIGNIFICANT COLD FRONT WILL SWEEP SOUTH THROUGH THE FCST AREA
SATURDAY PRODUCING HIGHS IN THE 80S WITH DRY CONDITIONS.
SUNDAY THROUGH WEDNESDAY...DRY WEATHER IS EXPECTED. THE DROUGHT
RIDGE WILL GRADUALLY BUILD NORTH TOWARD THE CNTL PLAINS AND
ANOTHER STRONG NORTHERN STREAM LOW WILL BEGIN TRACKING ALONG THE
CANADIAN BORDER. THIS SHOULD SPAWN A HIGH PLAINS LOW PRESSURE
SYSTEM AND DRAW WARM AIR BACK NORTH. TEMPS SHOULD RISE BACK INTO
THE LOW TO MID 90S NEXT WEEK. A COLD FRONT SHOULD MOVE THROUGH
LATE TUESDAY OR WEDNESDAY FOR COOLER HIGHS WEDNESDAY .
TEMPERATURES THURSDAY AND FRIDAY ARE A COMPLEX BLEND OF BIAS
CORRECTED MODEL DATA AND GUIDANCE. THE MODELS ARE FCSTING DEEP
MOISTURE AND STRATUS FRIDAY AND SATURDAY MORNINGS WHICH COULD HAVE
A BIG IMPACT ON HIGH TEMPERATURES.
&&
.AVIATION...
GUSTY SOUTHERLY WINDS WILL IMPACT MUCH OF WESTERN NEBRASKA THROUGH
THIS EVENING. MAY SEE GUSTS BACK OFF A BIT LATER THIS EVENING...BUT
WITH A TIGHT PRESSURE GRADIENT SHOULD STAY FAIRLY BREEZY
THROUGH THE OVERNIGHT HOURS. ALSO OF CONSIDERATION...THE LOW LEVEL
JET WILL PICK UP THIS EVENING...WITH SOUNDINGS INDICATING WINDS JUST
ABOVE THE SURFACE OF 40KTS. THINK WITH SURFACE WINDS STAYING
HIGHER...LOW LEVEL WIND SHEAR IS NOT NEEDED AT THIS TIME. SCATTERED
TO BROKEN CLOUD COVER IS EXPECTED THROUGH THE PERIOD...HOWEVER
CEILINGS WILL REMAIN VFR. ALSO...THERE IS POTENTIAL FOR
THUNDERSTORMS TO DEVELOP INTO THE EVENING OVER THE PANHANDLE AND
INTO NORTHWEST NEBRASKA. THE HIGHEST PROBABILITY FOR
ANY STORMS WILL BE WEST OF A LINE FROM KOGA TO KTIF TO KANW.
CONFIDENCE IS LOW ON COVERAGE OF ANY ACTIVITY THIS AFTERNOON...OR
HOW FAR EAST IT WILL MAKE IT SO JUST INCLUDED A VCTS INTO THE KVTN
TAF FOR THIS ISSUANCE.
&&
.FIRE WEATHER...
AS FUELS REMAIN VERY DRY...CONDITIONS THROUGH THE REMAINDER OF THIS
AFTERNOON WILL BE CRITICAL OR NEAR CRITICAL ACROSS MUCH OF WESTERN
AND NORTH CENTRAL NEBRASKA WITH RELATIVE HUMIDITY NEAR 20 PERCENT
AND GUSTY WINDS. FOR FIRE ZONE 209...A RED FLAG WARNING WILL
CONTINUE THROUGH 8 PM CDT.
WINDS WILL STAY BREEZY AND CONTINUE TO GUST TO 25 MPH OR HIGHER THIS
EVENING DUE TO A TIGHT PRESSURE GRADIENT AND STRONG WINDS ALOFT
MIXING DOWN TO THE SURFACE. THESE WINDS WILL DIMINISH SLIGHTLY INTO
THURSDAY MORNING...WITH GUSTS ON THURSDAY EXPECTED TO BE LESSER
ACROSS THE DISTRICTS. IN TERMS OF HUMIDITY...COOLING TEMPERATURES
THIS EVENING WILL CAUSE THE AIR TO BECOME MORE HUMID...WHICH WILL
ALLEVIATE THE DISTRICTS FROM THE CRITICAL FIRE WEATHER CONDITIONS.
IN ADDITION...THERE IS POTENTIAL FOR THUNDERSTORMS ALONG AND WEST OF
A LINE FROM OGALLALA TO THEDFORD TO AINSWORTH THIS EVENING. ANY
THUNDERSTORMS WILL HAVE THREATS ERRATIC AND GUSTY WINDS AND DRY
LIGHTNING...AS THE BOUNDARY LAYER IS VERY DRY. BELIEVE ANY STORMS
WILL BE ISOLATED IN NATURE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...RED FLAG WARNING UNTIL 8 PM CDT
THIS EVENING FOR NEZ209.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...BROOKS
AREA FORECAST DISCUSSION
NWS AMARILLO TX
321 PM CDT WED AUG 22 2012
.DISCUSSION...
ALREADY SEEING A TRANSITION FROM NORTHWESTERLY FLOW ALOFT TO MORE
WESTERLY FLOW ALOFT IN RESPONSE TO THE APPROACHING CUTOFF LOW
CURRENTLY IN SOUTHERLY CA.
FOR TONIGHT...STORMS FROM THE HIGHER TERRAIN OF NM AND CO WILL
QUICKLY MOVE INTO THE NORTHWESTERN PANHANDLES. THE RAP IS SHOWING
THIS AREA WITH SLIGHTLY HIGHER CAPE VALUES...NEAR 2000 J/KG...AND
MODEST SHEAR VALUES NEAR 30 KT. HOWEVER...THE SEVERE THREAT SHOULD
NOT LAST LONG AS MODEL SOUNDINGS SHOW ONLY ELEVATED INSTABILITY BY
03Z.
TOMORROW AND TOMORROW NIGHT...WILL PROBABLY BE THE BEST CHANCE FOR A
WIDESPREAD RAIN EVENT...ESPECIALLY TOMORROW NIGHT...WITH VORTICITY
ADVECTION AHEAD OF THE MAIN UPPER LEVEL TROUGH. THE BIGGER CONCERN
HOWEVER WILL BE THE POTENTIAL FOR HEAVY RAIN LEADING TO LOCALIZED
FLASH FLOODING...AS PRECIPITABLE WATER VALUES COULD BE ABOVE 1.5
INCHES AND MEAN STORM MOTIONS COULD BE BELOW 20 KT.
FRIDAY THROUGH SUNDAY...SOME CHANCES FOR THUNDERSTORMS CONTINUE
THROUGH THIS PERIOD. HOWEVER...THERE IS UNCERTAINTY IN THE TRACK OF
THE CENTER OF THE UPPER LEVEL LOW. IF THE LOW GOES JUST SOUTH OF THE
TX PANHANDLE AS THE GFS SHOWS...THERE SHOULD BE A RELATIVELY GOOD
CHANCE FOR RAIN THROUGH THE WEEKEND. HOWEVER...ANY DEVIATION TO THE
NORTH...LIKE THE ECMWF SHOWING THE LOW LIFTING NE ACROSS THE TX
PANHANDLE ON SAT...COULD MEAN THE REGION WOULD BE IN THE PRIME
LOCATION FOR THE DRY SLOT...AND THUS HAVE FEW IF ANY CHANCES FOR
STORMS. LIKELY THIS UNCERTAINTY WILL REMAIN FOR THE NEXT FEW MODEL
RUNS AS THE PATH OF THIS LOW IS SOMEWHAT DEPENDENT ON THE EVOLUTION
OF A SECOND UPPER LEVEL TROUGH THAT SHOULD MOVE ACROSS THE NORTHERN
TIER OF THE U.S. AT THE SAME TIME...BUT HAS NOT YET BEEN WELL SAMPLED
BY THE UPPER AIR NETWORK.
MONDAY THROUGH WEDNESDAY...A RIDGE IS EXPECTED TO BUILD OVER THE HIGH
PLAINS...MINIMIZING THE CHANCE FOR RAIN AND BRINGING A WARMING TREND
AT LEAST TO START THE WEEK.
JOHNSON
&&
.FIRE WEATHER...
RELATIVELY HIGH ATMOSPHERIC MOISTURE...AND CONTINUED RAIN CHANCES
SHOULD PRECLUDE ANY ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS FOR
THE NEXT SEVERAL DAYS.
JOHNSON
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 64 84 65 89 65 / 20 30 40 30 30
BEAVER OK 67 89 67 92 68 / 20 30 40 40 40
BOISE CITY OK 64 91 64 89 63 / 30 30 40 30 30
BORGER TX 67 87 68 91 69 / 20 30 40 30 30
BOYS RANCH TX 66 89 66 92 65 / 30 30 40 30 30
CANYON TX 64 85 64 89 64 / 20 30 40 30 20
CLARENDON TX 65 89 68 90 67 / 20 30 40 30 30
DALHART TX 64 91 63 90 61 / 30 30 40 30 30
GUYMON OK 65 89 66 91 66 / 30 30 40 30 40
HEREFORD TX 64 86 63 89 62 / 20 30 40 20 20
LIPSCOMB TX 67 87 69 89 69 / 20 30 40 40 40
PAMPA TX 64 87 66 87 65 / 20 30 40 30 30
SHAMROCK TX 66 86 68 87 68 / 20 30 40 40 40
WELLINGTON TX 66 90 68 89 70 / 20 30 40 30 30
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
03/16
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
314 PM CDT WED AUG 22 2012
.SHORT TERM...
EARLIER SHOWERS AND STORMS ACROSS THE BIG COUNTRY HAVE NOW
DISSIPATED FOR THE MOMENT. HOWEVER...CU FIELD HAS STARTED TO DEVELOP
ONCE AGAIN...AND THE VARIOUS WRF MODELS AND THE HRRR ALL SHOW SOME
VARYING DEGREE OF CONVECTION POPPING UP ACROSS WEST CENTRAL TEXAS
FOR A FEW HOURS LATE THIS AFTERNOON AND INTO THE EVENING. WILL
INCLUDE A MENTION OF ISOLATED STORMS FOR THE FIRST PERIOD.
OTHERWISE...FAIRLY QUIET PATTERN FOR THE NEXT 36 HOURS. LEE TROUGH
BECOMES BETTER ESTABLISHED ACROSS THE EASTERN NEW MEXICO AND WEST
TEXAS...WITH SOUTHERLY WINDS INCREASING AHEAD OF IT. MORE HIGH
CLOUDS ON THURSDAY......BUT NOT ENOUGH TO HAVE A REALLY SIGNIFICANT
EFFECT ON TEMPERATURES.
07
.LONG TERM...
A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS IS FORECAST FOR PARTS
OF THE AREA DURING THE FIRST PART OF THE EXTENDED FORECAST. AN UPPER
LEVEL HIGH WILL BEGIN TO SHIFT SOUTH INTO MEXICO THURSDAY...WHILE AN
UPPER LEVEL TROUGH APPROACHES FROM THE WEST. AT THE SAME TIME A LEE
TROUGH WILL DEVELOP OVER THE TEXAS PANHANDLE...RESULTING IN
INCREASING SOUTH TO SOUTHEAST WINDS. SHOWERS AND THUNDERSTORMS MAY
DEVELOP OVER PARTS OF WEST TEXAS BY LATE AFTERNOON/EARLY EVENING
THURSDAY...WHERE BETTER SURFACE CONVERGENCE IS EXPECTED. A FEW OF
THESE STORMS MAY DRIFT INTO PARTS OF OUR WESTERN COUNTIES...SO HAVE
INCLUDED SLIGHT CHANCE POPS AFTER 00Z FRIDAY.
MODELS ARE HINTING AT A COUPLE OF SHORTWAVE TROUGHS MOVING ACROSS
NORTH TEXAS. THE FIRST IS WEAKER AND IS FORECAST TO TREK ACROSS THE
PANHANDLE EARLY FRIDAY MORNING. AT THIS TIME...BELIEVE THE MAJORITY
OF PRECIPITATION WILL REMAIN NORTH OF OUR AREA...BUT KEPT SLIGHT
CHANCE POPS OVER THE NORTHERN BIG COUNTRY. THE NEXT...MORE
POTENT...UPPER LEVEL SHORTWAVE TROUGH WILL APPROACH FRIDAY THEN MOVE
ACROSS NORTH TEXAS AND OKLAHOMA SATURDAY. ONCE AGAIN...ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE...WITH THE
FAVORED AREAS BEING OUR NORTHERN AND WESTERN COUNTIES. I KEPT SLIGHT
CHANCE POPS IN FOR FRIDAY AND INTRODUCED SLIGHT CHANCE POPS ON
SATURDAY FOR THE WESTERN HALF OF THE REGION. BEYOND
SATURDAY...MODELS ARE HINTING AT A WEAK COLD FRONT MOVING INTO THE
TEXAS PANHANDLE SUNDAY...WITH SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING JUST NORTH OF OUR AREA. FOR NOW...I HAVE LEFT THE
FORECAST DRY BEYOND SATURDAY...BUT FUTURE SHIFTS MAY NEED TO
INTRODUCE POPS. HIGH TEMPERATURES THROUGH THE EXTENDED WILL BE NEAR
TO SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD...GENERALLY IN THE MID
90S.
DANIELS
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 69 94 73 93 74 / 10 10 10 20 20
SAN ANGELO 68 95 73 95 75 / 10 10 10 20 20
JUNCTION 67 93 72 94 74 / 20 10 10 10 20
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07/DANIELS
AREA FORECAST DISCUSSION...CORRECTED
NWS GREEN BAY WI
245 PM CDT WED AUG 22 2012
.SHORT TERM...TONIGHT AND THURSDAY.
MAIN CONCERN FOR THIS PERIOD WILL BE THE CHANCES FOR SHOWERS AND
THUNDERSTORMS TONIGHT AND WEDNESDAY...THEN HIGH TEMPERATURES
WEDNESDAY AFTERNOON.
A CLUSTER OF SHOWERS AND THUNDERSTORMS DEVELOPED ACROSS SOUTHERN
MINNESOTA THIS MORNING AND WAS NOW NEAR THE MINNEAPOLIS AREA. THE
SHOWERS AND STORMS DEVELOPED DUE TO WEAK LOW LEVEL JET...850/700MB
WARM ADVECTION AND STEEP MID LEVEL LAPSE RATES. THESE STORMS PRODUCED
HALF OF A HALF INCH TO HALF DOLLAR SIZE HAIL THIS AFTERNOON. MOST OF
THE BASES OF THESE STORMS WERE AROUND 10 THOUSAND FEET. MODELS DID
NOT HAVE A GOOD HANDLE ON THE DEVELOPMENT OF THIS CLUSTER OF STORMS
AND ALSO DIFFER ON THE EVOLUTION OF THIS CLUSTER OF STORMS AS IT
MOVES EAST INTO WISCONSIN.
THE WRF INDICATES THE 850/700MB WARM ADVECTION WILL MOVE ACROSS
THE AREA TONIGHT WITH THE GREATEST WARM ADVECTION NORTH AND WEST OF
GREEN BAY AND THE FOX VALLEY. DO NOT SEE WHY CONVECTION WOULD END
THIS AFTERNOON AND THIS IS SUPPORTED BY THE LATEST RUC MODEL.
LOOKING AT SOME OF THE MESOSCALE MODELS LIKE THE SPC WRF AND THE
WRF ARW INDICATED ISOLATED TO SCATTERED CONVECTION LATE THIS EVENING
AND OVERNIGHT. HAVE INCREASED CHANCES FOR RAIN AND DID INCLUDE THUNDER
IN THE MORNING UPDATE.
AS FOR THE HWO...WILL MAKE LAST MINUTE DECISION TO ADD HAIL. IT
APPEARS THAT THE RISK FOR LARGE HAIL WILL BE VERY LOW...BUT COULD
NOT RULE IT OUT SINCE LARGE HAIL WAS REPORTED IN MINNESOTA THIS
AFTERNOON.
ON THURSDAY...WARM FRONT WILL CONTINUE TO PUSH NORTH. TEMPERATURES
WERE INCREASED BY A FEW DEGREES...ESPECIALLY ACROSS THE SOUTH DUE
850MB TEMPERATURES AND BASED ON WHAT IS HAPPENING SOUTH OF THE
WARM FRONT TODAY. VERY LOW HUMIDITIES CAN BE EXPECTED...ESPECIALLY
FROM WISCONSIN RAPIDS TO WAUPACA TO WAUTOMA WHERE THEY SHOULD BE
DOWN TO AROUND 25 PERCENT. CONTINUED CHANCES FOR SHOWERS AND
STORMS ON THURSDAY ACROSS THE NORTH. THE 12Z WRF/GFS DID SPIT OUT
A FEW HUNDREDTHS OF AN INCH ACROSS PORTIONS OF CENTRAL AND EASTERN
WISCONSIN. PER COORDINATION WITH MILWAUKEE...THIS DID NOT SEEM
LIKE A FEASIBLE SCENARIO BASED ON MODEL SOUNDINGS.
.LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...PCPN TRENDS AND
TEMPERATURES ARE THE MAIN FCST CONCERNS.
AN UPPER TROF IS EXPECTED TO MOVE THROUGH THE REGION LATE THURSDAY
NIGHT INTO FRIDAY. BEFORE THE TROF ARRIVES...A WEAK WARM FRONT MAY
STILL BE IN PLACE OVER N WI...SO HAVE POPS CONFINED TO THE NORTHWOODS
DURING THE EVG HOURS. MODELS HAVE TRENDED SLOWER WITH THE ARRIVAL
OF THE UPPER TROF AND ASSOCIATED PCPN...SO WILL ONLY HAVE CHC POPS
FOR PARTS OF NC/C WI LATE THURSDAY NIGHT. THE TROF IS EXPECTED TO
WEAKEN SOMEWHAT AS IT MOVES THROUGH ON FRIDAY...SO SLGT CHC TO
CHC POPS SEEM REASONABLE.
WEAK RIDGING AT THE SFC AND ALOFT SHOULD ALLOW FOR A DRY PERIOD ON
FRIDAY NIGHT. A WEAK INSTABILITY AXIS OVER NC WI ON SATURDAY MAY
ALLOW FOR ISOLD TSTMS...MAINLY DURING THE AFTERNOON.
VERY WARM CONDITIONS WILL PREVAIL OVER THE FORECAST AREA FRIDAY
INTO SATURDAY...WITH HIGH TEMPS IN THE 80S TO LOWER 90S. AS HAS
BEEN THE CASE ALL SUMMER...THE WARMEST TEMPS WILL BE OVER THE
SANDY SOIL AREAS IN CENTRAL WI.
A COLD FRONT IS EXPECTED TO MOVE THROUGH THE AREA LATE SATURDAY
NIGHT INTO SUNDAY EVENING. THE GFS/ECMWF OFFER VERY DIFFERENT
SOLUTIONS WITH REGARD TO PCPN/QPF...WITH THE GFS MUCH WETTER THAN
THE ECMWF. SUSPECT THAT THE ECMWF SOLN IS MORE LIKELY...WITH MOST
OF THE UPPER LEVEL ENERGY PASSING NORTH OF THE RGN. THE GFS MODEL
MAY ALSO BE EXHIBITING SOME PROBLEMS WITH CONVECTIVE FEEDBACK...
LEADING TO ENHANCED S/W ENERGY ENERGY APPROACHING FROM THE CENTRAL
PLAINS. WILL STICK WITH THE MODEL BLEND FOR NOW DURING THIS
PERIOD...WITH MID-RANGE POPS.
AFTER THE FRONT MOVES THROUGH...CANADIAN HIGH PRESSURE WILL BUILD
INTO THE REGION FOR MONDAY INTO TUESDAY...RESULTING MORE SEASONABLE
TEMPERATURES AND DRY CONDITIONS.
&&
.AVIATION...CONVECTION IS MAIN CONCERN TONIGHT INTO THURSDAY.
A CLUSTER OF SHOWERS AND STORMS FROM MINNEAPOLIS TO NEAR LA
CROSSE THIS AFTERNOON WILL GRADUALLY MOVE EAST INTO CENTRAL
WISCONSIN LATE THIS AFTERNOON OR EARLY THIS EVENING. MODELS
SOLUTIONS VARY FROM THE AREA OF SHOWERS AND STORMS ENDING TO
OTHER MODELS BRINGING IT ACROSS THE AREA THIS EVENING INTO
THE OVERNIGHT. THE COMBINATION OF WARM ADVECTION IN THE LOW
LEVELS OF THE ATMOSPHERE AND STEEP MID LEVEL LAPSE RATES WOULD
SUGGEST ACTIVITY WOULD CONTINUE TO MOVE ACROSS THE AREA TONIGHT
INTO THURSDAY MORNING. THERE WILL MORE THAN LIKELY NEED TO ADD
PRECIPITATION TO THE TAFS THIS AFTERNOON OR WITH THE 00Z TAFS.
MESOSCALE MODELS ALSO SUGGEST ISOLATED TO SCATTERED CONVECTION
OVERNIGHT...WITH THE GREATEST CONCENTRATION OF SHOWERS AND STORMS
NORTH AND WEST OF GREEN BAY AND THE FOX CITIES.
WARM FRONT WILL CONTINUE TO PUSH NORTH ON THURSDAY. THERE IS A
CONTINUED CHANCES FOR SHOWERS AND STORMS NORTH OF A MERRILL TO
STURGEON BAY LINE. &&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
ECKBERG/KIECKBUSCH
AREA FORECAST DISCUSSION...CORRECTED
NWS GREEN BAY WI
220 PM CDT WED AUG 22 2012
.SHORT TERM...TONIGHT AND THURSDAY.
MAIN CONCERN FOR THIS PERIOD WILL BE THE CHANCES FOR SHOWERS AND
THUNDERSTORMS TONIGHT AND WEDNESDAY...THEN HIGH TEMPERATURES
WEDNESDAY AFTERNOON.
A CLUSTER OF SHOWERS AND THUNDERSTORMS DEVELOPED ACROSS SOUTHERN
MINNESOTA THIS MORNING AND WAS NOW NEAR THE MINNEAPOLIS AREA. THE
SHOWERS AND STORMS DEVELOPED DUE TO WEAK LOW LEVEL JET...850/700MB
WARM ADVECTION AND STEEP MID LEVEL LAPSE RATES. THESE STORMS PRODUCED
HALF OF A HALF INCH TO HALF DOLLAR SIZE HAIL THIS AFTERNOON. MOST OF
THE BASES OF THESE STORMS WERE AROUND 10 THOUSAND FEET. MODELS DID
NOT HAVE A GOOD HANDLE ON THE DEVELOPMENT OF THIS CLUSTER OF STORMS
AND ALSO DIFFER ON THE EVOLUTION OF THIS CLUSTER OF STORMS AS IT
MOVES EAST INTO WISCONSIN.
THE WRF INDICATES THE 850/700MB WARM ADVECTION WILL MOVE ACROSS
THE AREA TONIGHT WITH THE GREATEST WARM ADVECTION NORTH AND WEST OF
GREEN BAY AND THE FOX VALLEY. DO NOT SEE WHY CONVECTION WOULD END
THIS AFTERNOON AND THIS IS SUPPORTED BY THE LATEST RUC MODEL.
LOOKING AT SOME OF THE MESOSCALE MODELS LIKE THE SPC WRF AND THE
WRF ARW INDICATED ISOLATED TO SCATTERED CONVECTION LATE THIS EVENING
AND OVERNIGHT. HAVE INCREASED CHANCES FOR RAIN AND DID INCLUDE THUNDER
IN THE MORNING UPDATE.
AS FOR THE HWO...WILL MAKE LAST MINUTE DECISION TO ADD HAIL. IT
APPEARS THAT THE RISK FOR LARGE HAIL WILL BE VERY LOW...BUT COULD
NOT RULE IT OUT SINCE LARGE HAIL WAS REPORTED IN MINNESOTA THIS
AFTERNOON.
ON THURSDAY...WARM FRONT WILL CONTINUE TO PUSH NORTH. TEMPERATURES
WERE INCREASED BY A FEW DEGREES...ESPECIALLY ACROSS THE SOUTH DUE
850MB TEMPERATURES AND BASED ON WHAT IS HAPPENING SOUTH OF THE
WARM FRONT TODAY. VERY LOW HUMIDITIES CAN BE EXPECTED...ESPECIALLY
FROM WISCONSIN RAPIDS TO WAUPACA TO WAUTOMA WHERE THEY SHOULD BE
DOWN TO AROUND 25 PERCENT. CONTINUED CHANCES FOR SHOWERS AND
STORMS ON WEDNESDAY ACROSS THE NORTH. THE 12Z WRF/GFS DID SPIT OUT
A FEW HUNDREDTHS OF AN INCH ACROSS PORTIONS OF CENTRAL AND EASTERN
WISCONSIN. PER COORDINATION WITH MILWAUKEE...THIS DID NOT SEEM
LIKE A FEASIBLE SCENARIO BASED ON MODEL SOUNDINGS.
.LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...PCPN TRENDS AND
TEMPERATURES ARE THE MAIN FCST CONCERNS.
AN UPPER TROF IS EXPECTED TO MOVE THROUGH THE REGION LATE THURSDAY
NIGHT INTO FRIDAY. BEFORE THE TROF ARRIVES...A WEAK WARM FRONT MAY
STILL BE IN PLACE OVER N WI...SO HAVE POPS CONFINED TO THE NORTHWOODS
DURING THE EVG HOURS. MODELS HAVE TRENDED SLOWER WITH THE ARRIVAL
OF THE UPPER TROF AND ASSOCIATED PCPN...SO WILL ONLY HAVE CHC POPS
FOR PARTS OF NC/C WI LATE THURSDAY NIGHT. THE TROF IS EXPECTED TO
WEAKEN SOMEWHAT AS IT MOVES THROUGH ON FRIDAY...SO SLGT CHC TO
CHC POPS SEEM REASONABLE.
WEAK RIDGING AT THE SFC AND ALOFT SHOULD ALLOW FOR A DRY PERIOD ON
FRIDAY NIGHT. A WEAK INSTABILITY AXIS OVER NC WI ON SATURDAY MAY
ALLOW FOR ISOLD TSTMS...MAINLY DURING THE AFTERNOON.
VERY WARM CONDITIONS WILL PREVAIL OVER THE FORECAST AREA FRIDAY
INTO SATURDAY...WITH HIGH TEMPS IN THE 80S TO LOWER 90S. AS HAS
BEEN THE CASE ALL SUMMER...THE WARMEST TEMPS WILL BE OVER THE
SANDY SOIL AREAS IN CENTRAL WI.
A COLD FRONT IS EXPECTED TO MOVE THROUGH THE AREA LATE SATURDAY
NIGHT INTO SUNDAY EVENING. THE GFS/ECMWF OFFER VERY DIFFERENT
SOLUTIONS WITH REGARD TO PCPN/QPF...WITH THE GFS MUCH WETTER THAN
THE ECMWF. SUSPECT THAT THE ECMWF SOLN IS MORE LIKELY...WITH MOST
OF THE UPPER LEVEL ENERGY PASSING NORTH OF THE RGN. THE GFS MODEL
MAY ALSO BE EXHIBITING SOME PROBLEMS WITH CONVECTIVE FEEDBACK...
LEADING TO ENHANCED S/W ENERGY ENERGY APPROACHING FROM THE CENTRAL
PLAINS. WILL STICK WITH THE MODEL BLEND FOR NOW DURING THIS
PERIOD...WITH MID-RANGE POPS.
AFTER THE FRONT MOVES THROUGH...CANADIAN HIGH PRESSURE WILL BUILD
INTO THE REGION FOR MONDAY INTO TUESDAY...RESULTING MORE SEASONABLE
TEMPERATURES AND DRY CONDITIONS.
&&
.AVIATION...CONVECTION IS MAIN CONCERN TONIGHT INTO THURSDAY.
A CLUSTER OF SHOWERS AND STORMS FROM MINNEAPOLIS TO NEAR LA
CROSSE THIS AFTERNOON WILL GRADUALLY MOVE EAST INTO CENTRAL
WISCONSIN LATE THIS AFTERNOON OR EARLY THIS EVENING. MODELS
SOLUTIONS VARY FROM THE AREA OF SHOWERS AND STORMS ENDING TO
OTHER MODELS BRINGING IT ACROSS THE AREA THIS EVENING INTO
THE OVERNIGHT. THE COMBINATION OF WARM ADVECTION IN THE LOW
LEVELS OF THE ATMOSPHERE AND STEEP MID LEVEL LAPSE RATES WOULD
SUGGEST ACTIVITY WOULD CONTINUE TO MOVE ACROSS THE AREA TONIGHT
INTO THURSDAY MORNING. THERE WILL MORE THAN LIKELY NEED TO ADD
PRECIPITATION TO THE TAFS THIS AFTERNOON OR WITH THE 00Z TAFS.
MESOSCALE MODELS ALSO SUGGEST ISOLATED TO SCATTERED CONVECTION
OVERNIGHT...WITH THE GREATEST CONCENTRATION OF SHOWERS AND STORMS
NORTH AND WEST OF GREEN BAY AND THE FOX CITIES.
WARM FRONT WILL CONTINUE TO PUSH NORTH ON THURSDAY. THERE IS A
CONTINUED CHANCES FOR SHOWERS AND STORMS NORTH OF A MERRILL TO
STURGEON BAY LINE. &&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
ECKBERG/KIECKBUSCH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
215 PM CDT WED AUG 22 2012
.SHORT TERM...TONIGHT AND WEDNESDAY
MAIN CONCERN FOR THIS PERIOD WILL BE THE CHANCES FOR SHOWERS AND
THUNDERSTORMS TONIGHT AND WEDNESDAY...THEN HIGH TEMPERATURES
WEDNESDAY AFTERNOON.
A CLUSTER OF SHOWERS AND THUNDERSTORMS DEVELOPED ACROSS SOUTHERN
MINNESOTA THIS MORNING AND WAS NOW NEAR THE MINNEAPOLIS AREA. THE
SHOWERS AND STORMS DEVELOPED DUE TO WEAK LOW LEVEL JET...850/700MB
WARM ADVECTION AND STEEP MID LEVEL LAPSE RATES. THESE STORMS PRODUCED
HALF OF A HALF INCH TO HALF DOLLAR SIZE HAIL THIS AFTERNOON. MOST OF
THE BASES OF THESE STORMS WERE AROUND 10 THOUSAND FEET. MODELS DID
NOT HAVE A GOOD HANDLE ON THE DEVELOPMENT OF THIS CLUSTER OF STORMS
AND ALSO DIFFER ON THE EVOLUTION OF THIS CLUSTER OF STORMS AS IT
MOVES EAST INTO WISCONSIN.
THE WRF INDICATES THE 850/700MB WARM ADVECTION WILL MOVE ACROSS
THE AREA TONIGHT WITH THE GREATEST WARM ADVECTION NORTH AND WEST OF
GREEN BAY AND THE FOX VALLEY. DO NOT SEE WHY CONVECTION WOULD END
THIS AFTERNOON AND THIS IS SUPPORTED BY THE LATEST RUC MODEL.
LOOKING AT SOME OF THE MESOSCALE MODELS LIKE THE SPC WRF AND THE
WRF ARW INDICATED ISOLATED TO SCATTERED CONVECTION LATE THIS EVENING
AND OVERNIGHT. HAVE INCREASED CHANCES FOR RAIN AND DID INCLUDE THUNDER
IN THE MORNING UPDATE.
AS FOR THE HWO...WILL MAKE LAST MINUTE DECISION TO ADD HAIL. IT
APPEARS THAT THE RISK FOR LARGE HAIL WILL BE VERY LOW...BUT COULD
NOT RULE IT OUT SINCE LARGE HAIL WAS REPORTED IN MINNESOTA THIS
AFTERNOON.
ON WEDNESDAY...WARM FRONT WILL CONTINUE TO PUSH NORTH. TEMPERATURES
WERE INCREASED BY A FEW DEGREES...ESPECIALLY ACROSS THE SOUTH DUE
850MB TEMPERATURES AND BASED ON WHAT IS HAPPENING SOUTH OF THE
WARM FRONT TODAY. VERY LOW HUMIDITIES CAN BE EXPECTED...ESPECIALLY
FROM WISCONSIN RAPIDS TO WAUPACA TO WAUTOMA WHERE THEY SHOULD BE DOWN
TO AROUND 25 PERCENT. CONTINUED CHANCES FOR SHOWERS AND STORMS ON
WEDNESDAY ACROSS THE NORTH. THE 12Z WRF/GFS DID SPIT OUT A FEW
HUNDREDTHS OF AN INCH ACROSS PORTIONS OF CENTRAL AND EASTERN WISCONSIN.
PER COORDINATION WITH MILWAUKEE...THIS DID NOT SEEM LIKE A
FEASIBLE SCENARIO BASED ON MODEL SOUNDINGS.
.LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...PCPN TRENDS AND
TEMPERATURES ARE THE MAIN FCST CONCERNS.
AN UPPER TROF IS EXPECTED TO MOVE THROUGH THE REGION LATE THURSDAY
NIGHT INTO FRIDAY. BEFORE THE TROF ARRIVES...A WEAK WARM FRONT MAY
STILL BE IN PLACE OVER N WI...SO HAVE POPS CONFINED TO THE NORTHWOODS
DURING THE EVG HOURS. MODELS HAVE TRENDED SLOWER WITH THE ARRIVAL
OF THE UPPER TROF AND ASSOCIATED PCPN...SO WILL ONLY HAVE CHC POPS
FOR PARTS OF NC/C WI LATE THURSDAY NIGHT. THE TROF IS EXPECTED TO
WEAKEN SOMEWHAT AS IT MOVES THROUGH ON FRIDAY...SO SLGT CHC TO
CHC POPS SEEM REASONABLE.
WEAK RIDGING AT THE SFC AND ALOFT SHOULD ALLOW FOR A DRY PERIOD ON
FRIDAY NIGHT. A WEAK INSTABILITY AXIS OVER NC WI ON SATURDAY MAY
ALLOW FOR ISOLD TSTMS...MAINLY DURING THE AFTERNOON.
VERY WARM CONDITIONS WILL PREVAIL OVER THE FORECAST AREA FRIDAY
INTO SATURDAY...WITH HIGH TEMPS IN THE 80S TO LOWER 90S. AS HAS
BEEN THE CASE ALL SUMMER...THE WARMEST TEMPS WILL BE OVER THE
SANDY SOIL AREAS IN CENTRAL WI.
A COLD FRONT IS EXPECTED TO MOVE THROUGH THE AREA LATE SATURDAY
NIGHT INTO SUNDAY EVENING. THE GFS/ECMWF OFFER VERY DIFFERENT
SOLUTIONS WITH REGARD TO PCPN/QPF...WITH THE GFS MUCH WETTER THAN
THE ECMWF. SUSPECT THAT THE ECMWF SOLN IS MORE LIKELY...WITH MOST
OF THE UPPER LEVEL ENERGY PASSING NORTH OF THE RGN. THE GFS MODEL
MAY ALSO BE EXHIBITING SOME PROBLEMS WITH CONVECTIVE FEEDBACK...
LEADING TO ENHANCED S/W ENERGY ENERGY APPROACHING FROM THE CENTRAL
PLAINS. WILL STICK WITH THE MODEL BLEND FOR NOW DURING THIS
PERIOD...WITH MID-RANGE POPS.
AFTER THE FRONT MOVES THROUGH...CANADIAN HIGH PRESSURE WILL BUILD
INTO THE REGION FOR MONDAY INTO TUESDAY...RESULTING MORE SEASONABLE
TEMPERATURES AND DRY CONDITIONS.
&&
.AVIATION...CONVECTION IS MAIN CONCERN TONIGHT INTO WEDNESDAY.
A CLUSTER OF SHOWERS AND STORMS FROM MINNEAPOLIS TO NEAR LA
CROSSE THIS AFTERNOON WILL GRADUALLY MOVE EAST INTO CENTRAL
WISCONSIN LATE THIS AFTERNOON OR EARLY THIS EVENING. MODELS
SOLUTIONS VARY FROM THE AREA OF SHOWERS AND STORMS ENDING TO
OTHER MODELS BRINGING IT ACROSS THE AREA THIS EVENING INTO
THE OVERNIGHT. THE COMBINATION OF WARM ADVECTION IN THE LOW
LEVELS OF THE ATMOSPHERE AND STEEP MID LEVEL LAPSE RATES WOULD
SUGGEST ACTIVITY WOULD CONTINUE TO MOVE ACROSS THE AREA TONIGHT
INTO WEDNESDAY MORNING. THERE WILL MORE THAN LIKELY NEED TO ADD
PRECIPITATION TO THE TAFS THIS AFTERNOON OR WITH THE 00Z TAFS.
MESOSCALE MODELS ALSO SUGGEST ISOLATED TO SCATTERED CONVECTION
OVERNIGHT...WITH THE GREATEST CONCENTRATION OF SHOWERS AND STORMS
NORTH AND WEST OF GREEN BAY AND THE FOX CITIES.
WARM FRONT WILL CONTINUE TO PUSH NORTH ON WEDNESDAY. THERE IS A
CONTINUED CHANCES FOR SHOWERS AND STORMS NORTH OF A MERRILL TO
STURGEON BAY LINE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
ECKBERG/KIECKBUSCH
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1250 PM CDT WED AUG 22 2012
.UPDATE...
HIGH PRESSURE RIDGE OVER WISCONSIN IS KEEPING THE DRY AIR IN PLACE.
SKIES ARE CLEAR ACROSS ALL OF SOUTHERN WI. THUNDERSTORMS IN SOUTH
CENTRAL MINNESOTA ASSOCIATED WITH 850 AND 700MB WARM AIR ADVECTION
ON THE NOSE OF THE 850MB LOW LEVEL JET ARE EXPECTED TO GENERALLY
BREAK APART AS THEY MOVE INTO FAR WESTERN WI THIS AFTERNOON.
THEREFORE...KEPT THE FORECAST DRY.
FOR TONIGHT...TRICKY FORECAST SINCE THERE DOES APPEAR TO BE A SMALL
CHANCE FOR ELEVATED THUNDERSTORMS WITH THE WARM AIR ADVECTION IN OUR
NORTHWEST FORECAST AREA. THERE IS A LOT OF MODEL SPREAD FOR PRECIP
CHANCES TONIGHT. THE LATEST 14Z HRRR NOW FOLLOWS THE IDEA OF THE 12Z
NAM AND SPREADS STORMS INTO THE WESTERN FORECAST AREA THIS EVENING.
OVERALL IT APPEARS THE BETTER CHANCE FOR PRECIP WILL BE TO OUR NORTH
AND WEST...CLOSER TO THE 850MB LOW LEVEL JET AND WARM AIR ADVECTION.
&&
.AVIATION/18Z TAFS/...
VFR CONDITIONS THROUGH THE FORECAST PERIOD. THERE ARE A LOT OF MODEL
DIFFERENCES...BUT THERE DOES NOT APPEAR TO BE A GOOD CHANCE FOR
STORMS REACHING ANY OF THE TAF SITES TONIGHT. ELEVATED CONVECTION
SHOULD REMAIN TO OUR NORTH AND WEST WITH THE BETTER WARM AIR
ADVECTION AND LOW LEVEL JET.
MODELS ARE GENERATING LIGHT QPF IN THE EASTERN FORECAST AREA THU
AFTERNOON...BUT NOT BUYING IT GIVEN THE LOW LEVEL DRY AIR. THE
MODELS MAY BE HINTING AT MORE WIDESPREAD CUMULUS CLOUD COVER IN
THAT AREA.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...REM
THURSDAY THROUGH TUESDAY...DDV