Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/29/12
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1125 PM MDT SUN AUG 26 2012
.AVIATION...
VFR CONDITIONS WITH LIGHT DIURNAL WINDS ARE EXPECTED OVERNIGHT AND
THROUGH TOMORROW MORNING ACROSS THE FORECAST AREA...AND FOR THE 3
TAF SITES OF KCOS...KPUB AND KALS. ISOLATED CONVECTION MAY OCCUR
AT KCOS TOMORROW AFTERNOON/EARLY EVENING SO MENTIONED VCTS
THERE...AS WELL AS KALS BUT MORE SO OVER THE HIGHER TERRAIN ALONG
THE VALLEY EDGES. TOO LOW OF A PROBABILITY FOR MENTION AT KPUB.
&&
.PREV DISCUSSION... /ISSUED 245 PM MDT SUN AUG 26 2012/
SHORT TERM...
(TONIGHT AND MONDAY)
AN UPR RIDGE WL REMAIN CENTERED OVR SRN CO AND NRN NM THROUGH MON.
SHOWERS AND THUNDERSTORMS WILL CONTINUE OVR THE HIGHER TERRAIN THRU
THE EVENING HOURS...BUT ARE EXPECTED TO DIE OFF BY MIDNIGHT. THE NAM
RAP13 AND HRRR SHOW OF A LINE OF CONVECTION DEVELOPING OVR THE
EASTERN CO PLAINS LATER THIS AFTERNOON WHICH MOVES EASTWARD INTO
EARLY EVENING. SATELLITE AND RADAR ARE SHOWING A LINE OF SOME
CONVECTION ALONG A WEAK BOUNDARY THAT EXTENDS FROM NE CO AND
SOUTHWESTWARD WHICH HAS PRODUCED SOME THUNDERSTORMS IN NERN EL PASO
COUNTY. THE MODELS HAVE THE RIGHT IDEA...BUT NOT SURE HOW FAR
SOUTHWARD THE CONVECTION WL DEVELOP. WL GO WITH SOME ISOLD POPS OVR
AT LEAST NORTHERN PORTION OF THE SOUTHEAST PLAINS EARLY THIS EVENING.
ON MONDAY THERE WILL STILL BE SOME RESIDUAL MOISTURE UNDER THE RIDGE
OVR THE AREA...AND ISOLD TO SCT SHOWERS AND TSTMS ARE AGAIN EXPECTED
TO DEVELOP OVR THE HYR TRRN. THE SERN PLAINS SHOULD BE DRY ON
MONDAY. IN GENERAL...HIGH TEMPS SHOULD BE ABOUT 5-10 DEGREE ABOVE
AVERAGE. /28
LONG TERM...
(MONDAY NIGHT THROUGH SUNDAY)
..HOT AND DRY WEATHER TO CONTINUE THROUGH NEXT WEEK...
NO CHANGES SEEN FOR THE EXTENDED FORECAST. ALL GUIDANCE POINTS TO
A CONTINUATION OF CURRENT CONDITIONS. HIGH PRESSURE CENTERED OVR
S CO WILL BE THE MAIN PLAYER...AND THIS WILL LEAVE THE ERN CO PLAINS
IN A VERY WARM AND GENERALLY DRY PATTERN THRU AT LEAST THE MIDDLE OF
THE WEEK. TEMPS SHOULD TOP OUT IN THE MID 90S...POSSIBLY HIGHER...FOR
A GOOD PORTION OF THE PLAINS BOTH TUE AND WED. POPS LOOK PRETTY LOW
OVER THE PLAINS...AND ONLY SCT STORMS ARE EXPECTED OVR THE MTS FOR
THIS PERIOD.
MAIN QUESTION IS HOW QUICKLY THE UPPER RIDGE BREAKS DOWN. THE ECMWF
MAINTAINS A STRONG UPPER HIGH...AND KEEPS MOST OF THE ACTIVE WX TO
OUR N THRU THE END OF THE WEEK AND EVEN INTO NEXT WEEKEND. THE GFS IS
STILL MORE OPTIMISTIC AND BRINGS AT LEAST A LOW CHANCE OF PRECIP E
OF THE MTS AS A SERIES OF WEAK FRONTAL PUSHES MOVE ACROSS THE AREA
THU AND SAT NEXT WEEK. WILL STICK CLOSER TO PERSISTENCE FOR NOW AND
STAY CLOSE TO THE ENSEMBLE CONSENSUS...WHICH IS CLOSE TO THE OP
ECMWF FORECAST OF DRY AND VERY WARM CONDITIONS. 44
AVIATION...
SOME SHOWERS AND THUNDERSTORMS WILL CONTINUE OVR THE HYR TRRN INTO
THE EVENING BUT IS EXPECTED TO END BEFORE MIDNIGHT. KALS COULD SEE
SOME TSTMS IN THE VCNTY THRU ABOUT 02Z. AT KCOS AND KPUB...CHANCES
FOR TSTM LOOK QUITE LOW. VFR CONDITIONS ARE EXPECTED AT THE TAF
SITE FOR THE NEXT 24 HRS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
27/34
AREA FORECAST DISCUSSION
NWS ALBANY NY
647 AM EDT MON AUG 27 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE FROM THE GREAT LAKES TODAY TOWARDS THE
NORTHEAST TONIGHT. THIS WILL ALLOW FOR SOME SHOWERS AND
THUNDERSTORMS TO MOVE ACROSS THE REGION...ESPECIALLY DURING THE
OVERNIGHT HOURS. THE FRONT WILL PASS THROUGH THE AREA ON TUESDAY
MORNING...ALLOWING FOR DRIER AND COOLER WEATHER TO MOVE IN FOR THE
MID WEEK PERIOD.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 636 AM EDT...A SHORTWAVE TROUGH WAS MOVING ACROSS THE UPPER
GREAT LAKES THIS MORNING...WITH A SFC COLD FRONT MOVING ACROSS THE
MIDWEST. THIS TROUGH WILL QUICKLY MOVE EASTWARD ACROSS THE GREAT
LAKES THROUGH THE DAY TODAY.
AHEAD OF THIS SYSTEM...ANOTHER WEAK OPEN WAVE TROUGH WAS SITUATED
OVER THE MID ATLANTIC STATES. A SOUTHERLY FLOW HAS ALLOWED FOR
SOME STRATUS TO DEVELOP ACROSS PA/NJ...AND SOME
OF THESE LOW CLOUDS HAVE MOVED INTO PORTIONS OF THE EASTERN
CATSKILLS. HAVE GONE WITH MOSTLY CLOUDY FOR SOUTHWESTERN PARTS OF
THE AREA FOR THE EARLY TO MID MORNING HOURS. ELSEWHERE...MOSTLY CLEAR
SKIES WILL GRADUALLY GIVE WAY TO INCREASING AMOUNTS OF MID AND HIGH
LEVEL CLOUDINESS. WITH A PERSISTENT SOUTHERLY FLOW AND THE NEARBY
WEAK TROUGH OVER THE NORTHERN MID ATLANTIC STATES...A FEW LIGHT RAIN
SHOWERS OR ISOLD THUNDERSTORMS MAY DEVELOP FROM THE MID MORNING INTO
THE EARLY AFTERNOON HOURS. THE LATEST 07 UTC 3KM HRRR SHOWS SOME
ACTIVITY MOVING UP FROM THE SOUTH BY THE LATE MORNING. THE MOST
RECENT REGIONAL MOSAIC RADAR SHOWS SOME SHOWERS ALREADY ACROSS
EASTERN PA...AND WE WILL NEED TO WATCH THE EVOLUTION OF THESE
SHOWERS AS THEY LIFT N-NE. HAVE DECIDED TO INCLUDE AN ISOLD THUNDER
MENTION...AS THE THE 06 UTC NAM12 NOW SHOWS SOME INSTABILITY DURING
THE DAYTIME HOURS TODAY.
THE STRONGEST FORCING ASSOCIATED WITH THE MIDWEST SHORTWAVE
TROUGH WILL REMAIN WELL TO THE WEST THROUGH THE MID AFTERNOON. BY
LATER IN THE AFTERNOON...A SFC PRE FRONTAL TROUGH MAY DEVELOP AND
ALLOW FOR MORE SCT SHOWER ACTIVITY ACROSS THE AREA FOR THE LATE AFTN
HOURS. WILL CONTINUE TO MENTION THE ISOLD THREAT FOR SOME THUNDER.
MAX TEMPS WILL RANGE FROM THE UPPER 70S TO LOW 80S IN MOST AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
THERE MAY BE A BRIEF BREAK IN THE ACTIVITY DURING THE EARLY
EVENING HOURS...AS THE REGION WILL BE BETWEEN THE PRE FRONTAL
TROUGH AND THE ACTUAL APPROACHING SFC COLD FRONT/UPPER TROUGH.
BY LATER IN THE EVENING...THE REGION WILL BE BETTER LOCATED IN THE
FRONT ENTRANCE REGION OF AN 80 KT JET STREAK SITUATED OVER
NORTHERN NEW ENGLAND...AND THE UPPER TROUGH WILL BE QUICKLY
APPROACHING. THIS WILL ALLOW MORE WIDESPREAD SHOWERS TO DEVELOP.
WITH THE APPROACHING UPPER TROUGH...THERE WILL BE A LITTLE MORE
INSTABILITY...SO WILL CONTINUE TO INCLUDE THUNDER FOR THE
OVERNIGHT HOURS...AS THERE MAY BE SOME EMBEDDED RUMBLES OF
THUNDER...ALTHOUGH SEVERE WEATHER IS NOT ANTICIPATED DUE TO THE
SMALL AMOUNTS OF INSTABILITY AND LACK OF STRONG 0-6 KM BULK SHEAR.
STILL...SOME OF THE SHOWERS MAY HAVE SOME HEAVY DOWNPOURS...SEE
THE HYDRO SECTION BELOW FOR MORE INFORMATION REGARDING HOW THIS
MAY IMPACT AREA RIVERS AND STREAMS. WITH THE CLOUDS AND
RAINFALL...IT WILL BE A WARM AND MUGGY NIGHT. MANY AREAS WILL ONLY
DROP INTO THE MID TO UPPER 60S FOR LOWS.
THE MODELS ARE IN GOOD AGREEMENT THAT THE BEST CHANCE FOR
SHOWERS/STORMS LOOKS BETWEEN THE LATE EVENING AND EARLY MORNING
HOURS OF TUESDAY...SO HAVE GONE WITH LIKELY POPS ACROSS MUCH OF
THE AREA DURING THIS TIME PERIOD. THE SFC COLD FRONT WILL PASS
FROM WEST TO EAST DURING THE MORNING HOURS. THIS SHOULD ALLOW
WINDS TO SWITCH AROUND TO THE W-NW AND END THE THREAT OF SHOWERS.
MOST AREAS SHOULD BE RAIN FREE BY THE AFTERNOON HOURS...ALTHOUGH
THE THREAT FOR A SHOWER MAY LINGER IN WESTERN NEW ENGLAND INTO THE
MID AFTN. MAX TEMPS WILL RANGE FROM NEAR 70 IN THE ADIRONDACKS TO
THE MID 80S IN FAR SOUTHEASTERN AREAS...WHERE THE FRONT WILL TAKE
LONGEST TO CROSS.
A LARGE AREA OF HIGH PRESSURE OVER THE MIDWEST WILL SHIFT EASTWARD
TOWARDS THE REGION FOR TOMORROW NIGHT. THIS WILL ALLOW DRY WEATHER
TO RETURN TO THE AREA FOR TOMORROW NIGHT THROUGH THE REMAINDER OF
THE SHORT TERM PERIOD. COOLER AND LESS HUMID WILL MAKE ITS WAY
INTO THE AREA. WITH GOOD RADIATIONAL COOLING EXPECTED...LOWS
TOMORROW NIGHT WILL RANGE FROM THE MID 40S TO THE MID 50S ACROSS
THE AREA WITH CLEARING SKIES. MAX TEMPS ON WED WILL ONLY BE IN THE
70S ACROSS THE AREA...WITH THESE HIGHS BEING A FEW DEGREES BELOW
NORMAL. ANOTHER COOL NIGHT IS EXPECTED FOR WED NIGHT WITH MID 40S
TO MID 50S WITH A NEARLY CLEAR SKY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
RIDGING IS EXPECTED TO DOMINATE LATE IN THE WEEK WITH UNCERTAINTY
IN THE FORECAST GROWING OVER THE WEEKEND. THE GFS AND ECMWF ARE IN
GOOD AGREEMENT KEEPING THE REGION DRY THROUGH SATURDAY WITH RIDGING
ALOFT ACROSS THE NORTHEAST AND HIGH PRESSURE AT THE SURFACE ALONG
THE EAST COAST. ABOVE NORMAL TEMPERATURES ARE ANTICIPATED ESPECIALLY
FRIDAY AND SATURDAY BY AROUND 10 DEGREES.
AFTER LANDFALL ISAAC WILL WEAKENED AS IT MOVES INLAND. SOME MODEL
GUIDANCE INDICATES THE REMNANT MOISTURE FROM ISAAC MAY AFFECT OUR
REGION LATE IN THE WEEKEND INTO EARLY NEXT WEEK. PLEASE REFER TO
PRODUCTS ISSUED BY THE NATIONAL HURRICANE CENTER FOR THE OFFICIAL
FORECAST TRACK OF TROPICAL STORM ISAAC.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL CONTINUE TO SHIFT EASTWARD AND OFF THE NEW
ENGLAND COAST TODAY. A SLOW MOVING COLD FRONT WILL APPROACH AND MOVE
ACROSS THE REGION BRINGING INCREASING CHANCES OF SHOWERS AND SOME
THUNDERSTORMS THIS AFTERNOON AND ESPECIALLY TONIGHT.
MAINLY VFR CONDITIONS PERSIST EARLY THIS MORNING...EXCEPTION IS AT
KGFL WHERE RADIATIONAL FOG DEVELOPED. ALSO HAVE SOME STRATUS ACROSS
PORTIONS OF THE LOCAL AREA WHICH IMPACTED KPSF AND KPOU EARLIER THIS
MORNING. THE STRATUS WILL LIFT/BREAK UP AND THE FOG WILL BURN OFF.
ALSO HAVE CLOUDS ADVANCING IN FROM THE WEST AHEAD OF THE COLD FRONT.
CHANCES FOR CONVECTION WILL INCREASE AS THE AFTERNOON PROGRESSES AS
A PREFRONTAL TROUGH MOVES ACROSS THE REGION. THERE MAY BE A LULL IN
THE ACTIVITY THIS EVENING FOR A PERIOD BETWEEN THE PREFRONTAL TROUGH
AND THE COLD FRONT. WILL HAVE BETTER CHANCES FOR CONVECTION WITH THE
COLD FRONT AS IT WILL HAVE BETTER SUPPORT. EXCEPT WIDESPREAD MVFR
CONDITIONS TO DEVELOP WITH IFR POSSIBLE AS HEAVY DOWNPOURS WILL
OCCUR WITH SOME OF THE CONVECTION.
SOUTHERLY FLOW TODAY WITH THE STRONGEST WINDS DURING THE AFTERNOON
WITH SOME GUSTS UP TO AROUND 20 KTS AT KALB DUE TO THE FUNNELING
EFFECT UP THE HUDSON RIVER VALLEY. WINDS WILL LIGHTEN UP DURING THE
EVENING AND REMAIN SOUTHERLY.
OUTLOOK...
TUE...IMPROVING TO VFR. SHRA/TSRA LIKELY IN THE MORNING ESPECIALLY
EARLY.
WED-FRI...VFR.
&&
.FIRE WEATHER...
A COLD FRONT WILL MOVE FROM THE GREAT LAKES TODAY TOWARDS THE
NORTHEAST TONIGHT. THIS WILL ALLOW FOR SOME SHOWERS AND
THUNDERSTORMS TO MOVE ACROSS THE REGION...ESPECIALLY DURING THE
OVERNIGHT HOURS. THE FRONT WILL PASS THROUGH THE AREA ON TUESDAY
MORNING...ALLOWING FOR DRIER AND COOLER WEATHER TO MOVE IN FOR THE
MID WEEK PERIOD.
RELATIVE HUMIDITIES WILL ONLY FALL TO ABOUT 50-60 PERCENT THIS
AFTERNOON. RELATIVE HUMIDITIES TONIGHT WITH THE RAIN SHOULD APPROACH
100 PERCENT...THEN AS THE FRONT EXITS TUESDAY...RELATIVE
HUMIDITIES SHOULD DRY OUT TO THE 45 TO 55 PERCENT RANGE. RH VALUES
WILL THEN ONCE AGAIN APPROACH 100 PERCENT TOMORROW NIGHT.
SOUTH TO SOUTHWEST WINDS WILL PICK UP TO 10-15 MPH THIS AFTERNOON.
WEST TO SOUTHWEST WINDS WILL DROP TO AROUND 5 MPH TONIGHT. WINDS
WILL SWITCH TO A WEST TO NORTHWEST WINDS IN THE WAKE OF THE FRONT
FOR TOMORROW AFTERNOON AT SPEEDS OF 10-18 MPH WITH A FEW HIGHER
GUSTS POSSIBLE. WINDS WILL QUICKLY DROP OFF TO NEARLY CALM FOR
TOMORROW NIGHT.
&&
.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THROUGH AT LEAST THE
NEXT FIVE DAYS.
NUMEROUS SHOWERS AND SOME EMBEDDED THUNDERSTORMS WILL OCCUR FOR
LATER TODAY THROUGH TONIGHT AND INTO TUESDAY MORNING. WITH PWAT
VALUES AROUND 1.75 INCHES THROUGH THIS PERIOD...SOME HEAVY
DOWNPOURS ARE POSSIBLE WITHIN ANY OF THE SHOWERS AND
THUNDERSTORMS. THIS MAY LEAD TO PONDING OF WATER ON AREA ROADWAYS
AND IN AREAS OF POOR DRAINAGE. ALTHOUGH LOCALLY HIGHER AMOUNTS
ARE POSSIBLE...TOTAL AREAL QPF AMOUNTS WILL LIKELY BE AROUND A
HALF TO THREE QUARTERS OF AN INCH. AS A RESULT...WIDESPREAD
FLOODING IS NOT ANTICIPATED...AND DUE TO SUCH DRY ANTECEDENT
CONDITIONS...THIS RAINFALL WILL BE ABSORBED INTO THE GROUND...AND
RUNOFF WILL BE MINIMAL. THIS RAINFALL SHOULD ONLY ALLOW FOR SOME
SMALL RISES ON AREA RIVERS AND STREAMS AT MOST...WITH SOME LARGER
MAINSTEM RIVERS HOLDING STEADY.
MAINLY DRY WEATHER RETURNS TUESDAY AFTERNOON AND SHOULD LAST
THROUGH THE REST OF THE WORK WEEK.
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...FRUGIS
LONG TERM...IAA
AVIATION...IAA
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
636 AM EDT MON AUG 27 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE FROM THE GREAT LAKES TODAY TOWARDS THE
NORTHEAST TONIGHT. THIS WILL ALLOW FOR SOME SHOWERS AND
THUNDERSTORMS TO MOVE ACROSS THE REGION...ESPECIALLY DURING THE
OVERNIGHT HOURS. THE FRONT WILL PASS THROUGH THE AREA ON TUESDAY
MORNING...ALLOWING FOR DRIER AND COOLER WEATHER TO MOVE IN FOR THE
MID WEEK PERIOD.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 636 AM EDT...A SHORTWAVE TROUGH WAS MOVING ACROSS THE UPPER
GREAT LAKES THIS MORNING...WITH A SFC COLD FRONT MOVING ACROSS THE
MIDWEST. THIS TROUGH WILL QUICKLY MOVE EASTWARD ACROSS THE GREAT
LAKES THROUGH THE DAY TODAY.
AHEAD OF THIS SYSTEM...ANOTHER WEAK OPEN WAVE TROUGH WAS SITUATED
OVER THE MID ATLANTIC STATES. A SOUTHERLY FLOW HAS ALLOWED FOR
SOME STRATUS TO DEVELOP ACROSS PA/NJ...AND SOME
OF THESE LOW CLOUDS HAVE MOVED INTO PORTIONS OF THE EASTERN
CATSKILLS. HAVE GONE WITH MOSTLY CLOUDY FOR SOUTHWESTERN PARTS OF
THE AREA FOR THE EARLY TO MID MORNING HOURS. ELSEWHERE...MOSTLY CLEAR
SKIES WILL GRADUALLY GIVE WAY TO INCREASING AMOUNTS OF MID AND
HIGH LEVEL CLOUDINESS. WITH A PERSISTENT SOUTHERLY FLOW AND THE NEARBY
WEAK TROUGH OVER THE NORTHERN MID ATLANTIC STATES...A FEW LIGHT
RAIN SHOWERS OR ISOLD THUNDERSTORMS MAY DEVELOP FROM THE MID MORNING
INTO THE EARLY AFTERNOON HOURS. THE LATEST 07 UTC 3KM HRRR SHOWS
SOME ACTIVITY MOVING UP FROM THE SOUTH BY THE LATE MORNING. THE
MOST RECENT REGIONAL MOSAIC RADAR SHOWS SOME SHOWERS ALREADY
ACROSS EASTERN PA...AND WE WILL NEED TO WATCH THE EVOLUTION OF
THESE SHOWERS AS THEY LIFT N-NE. HAVE DECIDED TO INCLUDE AN ISOLD
THUNDER MENTION...AS THE THE 06 UTC NAM12 NOW SHOWS SOME
INSTABILITY DURING THE DAYTIME HOURS TODAY.
THE STRONGEST FORCING ASSOCIATED WITH THE MIDWEST SHORTWAVE
TROUGH WILL REMAIN WELL TO THE WEST THROUGH THE MID AFTERNOON. BY
LATER IN THE AFTERNOON...A SFC PRE FRONTAL TROUGH MAY DEVELOP AND
ALLOW FOR MORE SCT SHOWER ACTIVITY ACROSS THE AREA FOR THE LATE
AFTN HOURS. WILL CONTINUE TO MENTION THE ISOLD THREAT FOR SOME THUNDER.
MAX TEMPS WILL RANGE FROM THE UPPER 70S TO LOW 80S IN MOST AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
THERE MAY BE A BRIEF BREAK IN THE ACTIVITY DURING THE EARLY
EVENING HOURS...AS THE REGION WILL BE BETWEEN THE PRE FRONTAL
TROUGH AND THE ACTUAL APPROACHING SFC COLD FRONT/UPPER TROUGH.
BY LATER IN THE EVENING...THE REGION WILL BE BETTER LOCATED IN THE
FRONT ENTRANCE REGION OF AN 80 KT JET STREAK SITUATED OVER
NORTHERN NEW ENGLAND...AND THE UPPER TROUGH WILL BE QUICKLY
APPROACHING. THIS WILL ALLOW MORE WIDESPREAD SHOWERS TO DEVELOP.
WITH THE APPROACHING UPPER TROUGH...THERE WILL BE A LITTLE MORE
INSTABILITY...SO WILL CONTINUE TO INCLUDE THUNDER FOR THE
OVERNIGHT HOURS...AS THERE MAY BE SOME EMBEDDED RUMBLES OF
THUNDER...ALTHOUGH SEVERE WEATHER IS NOT ANTICIPATED DUE TO THE
SMALL AMOUNTS OF INSTABILITY AND LACK OF STRONG 0-6 KM BULK SHEAR.
STILL...SOME OF THE SHOWERS MAY HAVE SOME HEAVY DOWNPOURS...SEE
THE HYDRO SECTION BELOW FOR MORE INFORMATION REGARDING HOW THIS
MAY IMPACT AREA RIVERS AND STREAMS. WITH THE CLOUDS AND
RAINFALL...IT WILL BE A WARM AND MUGGY NIGHT. MANY AREAS WILL ONLY
DROP INTO THE MID TO UPPER 60S FOR LOWS.
THE MODELS ARE IN GOOD AGREEMENT THAT THE BEST CHANCE FOR
SHOWERS/STORMS LOOKS BETWEEN THE LATE EVENING AND EARLY MORNING
HOURS OF TUESDAY...SO HAVE GONE WITH LIKELY POPS ACROSS MUCH OF
THE AREA DURING THIS TIME PERIOD. THE SFC COLD FRONT WILL PASS
FROM WEST TO EAST DURING THE MORNING HOURS. THIS SHOULD ALLOW
WINDS TO SWITCH AROUND TO THE W-NW AND END THE THREAT OF SHOWERS.
MOST AREAS SHOULD BE RAIN FREE BY THE AFTERNOON HOURS...ALTHOUGH
THE THREAT FOR A SHOWER MAY LINGER IN WESTERN NEW ENGLAND INTO THE
MID AFTN. MAX TEMPS WILL RANGE FROM NEAR 70 IN THE ADIRONDACKS TO
THE MID 80S IN FAR SOUTHEASTERN AREAS...WHERE THE FRONT WILL TAKE
LONGEST TO CROSS.
A LARGE AREA OF HIGH PRESSURE OVER THE MIDWEST WILL SHIFT EASTWARD
TOWARDS THE REGION FOR TOMORROW NIGHT. THIS WILL ALLOW DRY WEATHER
TO RETURN TO THE AREA FOR TOMORROW NIGHT THROUGH THE REMAINDER OF
THE SHORT TERM PERIOD. COOLER AND LESS HUMID WILL MAKE ITS WAY
INTO THE AREA. WITH GOOD RADIATIONAL COOLING EXPECTED...LOWS
TOMORROW NIGHT WILL RANGE FROM THE MID 40S TO THE MID 50S ACROSS
THE AREA WITH CLEARING SKIES. MAX TEMPS ON WED WILL ONLY BE IN THE
70S ACROSS THE AREA...WITH THESE HIGHS BEING A FEW DEGREES BELOW
NORMAL. ANOTHER COOL NIGHT IS EXPECTED FOR WED NIGHT WITH MID 40S
TO MID 50S WITH A NEARLY CLEAR SKY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
RIDGING IS EXPECTED TO DOMINATE LATE IN THE WEEK WITH UNCERTAINTY
IN THE FORECAST GROWING OVER THE WEEKEND. THE GFS AND ECMWF ARE IN
GOOD AGREEMENT KEEPING THE REGION DRY THROUGH SATURDAY WITH RIDGING
ALOFT ACROSS THE NORTHEAST AND HIGH PRESSURE AT THE SURFACE ALONG
THE EAST COAST. ABOVE NORMAL TEMPERATURES ARE ANTICIPATED ESPECIALLY
FRIDAY AND SATURDAY BY AROUND 10 DEGREES.
AFTER LANDFALL ISAAC WILL WEAKENED AS IT MOVES INLAND. SOME MODEL
GUIDANCE INDICATES THE REMNANT MOISTURE FROM ISAAC MAY AFFECT OUR
REGION LATE IN THE WEEKEND INTO EARLY NEXT WEEK. PLEASE REFER TO
PRODUCTS ISSUED BY THE NATIONAL HURRICANE CENTER FOR THE OFFICIAL
FORECAST TRACK OF TROPICAL STORM ISAAC.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE CONTINUES TO SHIFT EAST AND WILL MOVE OFF THE NEW
ENGLAND COAST THIS MORNING. A SLOW MOVING COLD FRONT WILL MOVE
APPROACH AND MOVE THROUGH THE REGION BRINGING INCREASING CHANCES OF
SHOWERS AND PERHAPS SOME THUNDERSTORMS THIS AFTERNOON AND EVENING.
MAINLY VFR CONDITIONS PERSIST EARLY THIS MORNING...EXCEPTION IS AT
KPSF WHERE STRATUS DEVELOP OVER THE LOCAL AREA. THE 11-3.9 MICRON
SATELLITE SHOWS SOME STRATUS DEVELOPING OVER PORTIONS OF THE LOCAL
AREA...EAST CENTRAL NEW YORK AND ADJACENT WESTERN NEW ENGLAND.
WIDESPREAD STRATUS IS ACROSS MUCH OF PA INTO THE SOUTHERN TIER OF NY
AND INTO NORTHEAST NJ. THE STRATUS WILL LIFT/BREAK UP WITH MIXING
AFTER SUNRISE.
CHANCES FOR CONVECTION WILL INCREASE AS THE AFTERNOON PROGRESS INTO
THE EVENING. THERE MAY BE A LULL IN THE ACTIVITY BETWEEN A
PREFRONTAL TROUGH AND THE COLD FRONT. WITH BETTER CHANCES FOR
CONVECTION WITH THE COLD FRONT SINCE WILL HAVE BETTER SUPPORT.
SOUTHERLY FLOW TODAY WITH THE STRONGEST WINDS DURING THE AFTERNOON
WITH SOME GUSTS UP TO AROUND 20 KTS AT KALB DUE TO THE FUNNELING
EFFECT UP THE HUDSON RIVER VALLEY. WINDS WILL LIGHTEN UP DURING THE
EVENING AND REMAIN SOUTHERLY.
OUTLOOK...
TUE...IMPROVING TO VFR. SHRA/TSRA LIKELY IN THE MORNING ESPECIALLY
EARLY.
WED-SAT...VFR.
&&
.FIRE WEATHER...
A COLD FRONT WILL MOVE FROM THE GREAT LAKES TODAY
TOWARDS THE NORTHEAST TONIGHT. THIS WILL ALLOW FOR SOME SHOWERS AND
THUNDERSTORMS TO MOVE ACROSS THE REGION...ESPECIALLY DURING THE
OVERNIGHT HOURS. THE FRONT WILL PASS THROUGH THE AREA ON TUESDAY
MORNING...ALLOWING FOR DRIER AND COOLER WEATHER TO MOVE IN FOR THE
MID WEEK PERIOD.
RELATIVE HUMIDITIES WILL ONLY FALL TO ABOUT 50-60 PERCENT THIS
AFTERNOON. RELATIVE HUMIDITIES TONIGHT WITH THE RAIN SHOULD APPROACH
100 PERCENT...THEN AS THE FRONT EXITS TUESDAY...RELATIVE
HUMIDITIES SHOULD DRY OUT TO THE 45 TO 55 PERCENT RANGE. RH VALUES
WILL THEN ONCE AGAIN APPROACH 100 PERCENT TOMORROW NIGHT.
SOUTH TO SOUTHWEST WINDS WILL PICK UP TO 10-15 MPH THIS AFTERNOON.
WEST TO SOUTHWEST WINDS WILL DROP TO AROUND 5 MPH TONIGHT. WINDS
WILL SWITCH TO A WEST TO NORTHWEST WINDS IN THE WAKE OF THE FRONT
FOR TOMORROW AFTERNOON AT SPEEDS OF 10-18 MPH WITH A FEW HIGHER
GUSTS POSSIBLE. WINDS WILL QUICKLY DROP OFF TO NEARLY CALM FOR
TOMORROW NIGHT.
&&
.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THROUGH AT LEAST THE
NEXT FIVE DAYS.
NUMEROUS SHOWERS AND SOME EMBEDDED THUNDERSTORMS WILL OCCUR FOR
LATER TODAY THROUGH TONIGHT AND INTO TUESDAY MORNING. WITH PWAT
VALUES AROUND 1.75 INCHES THROUGH THIS PERIOD...SOME HEAVY
DOWNPOURS ARE POSSIBLE WITHIN ANY OF THE SHOWERS AND
THUNDERSTORMS. THIS MAY LEAD TO PONDING OF WATER ON AREA ROADWAYS
AND IN AREAS OF POOR DRAINAGE. ALTHOUGH LOCALLY HIGHER AMOUNTS
ARE POSSIBLE...TOTAL AREAL QPF AMOUNTS WILL LIKELY BE AROUND A
HALF TO THREE QUARTERS OF AN INCH. AS A RESULT...WIDESPREAD
FLOODING IS NOT ANTICIPATED...AND DUE TO SUCH DRY ANTECEDENT
CONDITIONS...THIS RAINFALL WILL BE ABSORBED INTO THE GROUND...AND
RUNOFF WILL BE MINIMAL. THIS RAINFALL SHOULD ONLY ALLOW FOR SOME
SMALL RISES ON AREA RIVERS AND STREAMS AT MOST...WITH SOME LARGER
MAINSTEM RIVERS HOLDING STEADY.
MAINLY DRY WEATHER RETURNS TUESDAY AFTERNOON AND SHOULD LAST
THROUGH THE REST OF THE WORK WEEK.
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...FRUGIS
LONG TERM...IAA
AVIATION...IAA
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1157 PM EDT TUE AUG 28 2012
.SYNOPSIS...
GREAT LAKES HIGH PRESSURE WILL CREST OVER OUR AREA ON THURSDAY
AND THEN SLIP DOWN TO THE CAROLINAS FRIDAY SENDING US A DAY OR TWO
OF HEAT. A COLD FRONTAL PASSAGE FROM THE NORTHWEST IS ANTICIPATED
SATURDAY. THE SHOWERY REMNANTS OF ISAAC MAY RIDE ALONG THAT FRONT
THROUGH OUR AREA LATE THIS LABOR DAY WEEKEND WITH ANOTHER COLD
FRONTAL PASSAGE POSSIBLE HERE LATE TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
A SECONDARY COLD FRONT WAS DROPPING THROUGH OUR REGION FROM NORTH
TO SOUTH THIS EVENING. IT HAD A WIND SHIFT ASSOCIATED WITH IT FROM
WEST NORTHWEST TO THE NORTH NORTHWEST.
THERE WERE FEW CLOUDS WITH THE FRONT. AS HIGH PRESSURE BEGINS TO
BUILD INTO OUR REGION TONIGHT, WE ARE ANTICIPATING A MOSTLY CLEAR
SKY. TEMPERATURES SHOULD DROP INTO THE 50S UP NORTH AND INTO THE
60S IN OUR CENTRAL AND SOUTHERN COUNTIES.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
HIGH PRESSURE WILL BUILD ACROSS THE REGION ON WEDNESDAY AS THE
DRYING TREND CONTINUES. CONDITIONS OUTSIDE WILL CERTAINLY FEEL
LESS HUMID AND PRETTY COMFORTABLE WITH HIGHS GENERALLY INTO THE
LOWER 80S. 850MB TEMPERATURES ARE AROUND 10-12C, WHICH SUPPORT
SURFACE TEMPERATURES IN THE UPPER 70S TO LOWER 80S.
A SHORTWAVE ROTATES THROUGH THE MID LEVEL FLOW DURING THE
AFTERNOON/EVENING BUT ALL THAT IT LOOKS TO BRING TO OUR AREA IS
CLOUDS AS THE ATMOSPHERE LOOKS TO BE TOO DRY FOR MUCH ELSE TO
OCCUR.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
500MB: A STRONG TROUGH IN COASTAL EASTERN CANADA WILL BE RELAXING
ITS INFLUENCE ON OUR AREA PERMITTING STRONG HOT RIDGING IN THE
CAROLINAS BY FRIDAY. THAT RIDGE REFORMS ALONG THE GULF COAST THIS
WEEKEND AS IT TRADES PLACES WITH THE DEPARTED ISAAC. MEANWHILE...
MODEL CONSENSUS TRACKS THE REMNANTS OF ISAAC EASTWARD INTO THE MID
ATLANTIC STATES EARLY NEXT WEEK....EITHER AS WARM FRONTAL WAVE ON
SATURDAYS COOL FRONT...OR ON A NEW N-S COLD FRONT FORMING IN THE
GREAT LAKES.
TEMPS: NEAR NORMAL THURSDAY THEN 5 TO 10 DEGREES ABOVE NORMAL
FRIDAY AND SATURDAY AND PROBABLY STILL ABOVE NORMAL SUNDAY THROUGH
TUESDAY BUT WITH LESS CERTAINTY ON DAY TO DAY DETAILS.
HAZARDS...NONE EVIDENT THROUGH SATURDAY. THEREAFTER...POSSIBLE
LOCALIZED FLOODING MONDAY INTO TUESDAY. THIS IS CONDITIONAL AND
STILL UNCERTAIN...TO ISAACS REMNANT MOISTURE/850 VORTICITY
FIELD/SURFACE MOISTURE CONVERGENCE TRACKING THROUGH THE MID
ATLANTIC STATES. NO HYDRO SECTION AS WE`RE TALKING DAYS 5-7 AND
THE MAXIMUM QPF MAY TRACK NORTH OF OUR AREA.
HEAT: HEAT INDEX IN THE MID 90S BOTH FRI AND SAT...BELOW CRITERIA
FOR HEAT ADVY BUT NOTABLE. MAX TEMPS NEAR 430 PM ON FRIDAY...LATE
DAY. FORTUNATELY RELATIVELY DRY HEAT.
WED NIGHT-THU NIGHT...COMFORTABLY COOL. PWATS BELOW NORMAL SO
NIGHTTIMES SHOULD BE COOLER THAN NORMAL. BLENDED 12Z/28 NCEP MOS
GUIDANCE WITH DRY HIGH PRESSURE AND SPECTACULAR LATE SUMMER
WEATHER FOR OUR AREA. LIGHT WIND. PATCHY FOG FOR AN HOUR OR 2 LATE
AT NIGHT IN THE USUAL COUNTRYSIDE LOCATIONS.
FRIDAY-SATURDAY...HEATS UP FOR A PROBABLE 2 DAY RUN OF 90-95F.
DEWPOINTS HIGHER ALONG THE COAST...UPPER 60S BUT INLAND...THESE
LOWER IN THE AFTN TO UPPER 50S AND LOWER 60S DELAWARE VALLEY
WESTWARD. WSW G AROUND 20 KTS FRI AND THEN A WEST WIND POSSIBLY
SHIFTING NW G UNDER 20 KTS SATURDAY. JUST RCD 12Z ECMWF KI/SWI
FIELDS SUGGEST THAT A SLIVER MOIST UNSTABLE AIR PRECEDES A WEAK
COOL FRONT THROUGH OUR AREA LATE FRI NIGHT. FOR NOW NO POPS SINCE
OCCURRENCE IS PROBABLY LATE AT NIGHT.
SUNDAY-TUESDAY...THE APPROACH OF ISAAC AND ITS UNCERTAINTIES ARE
CRITICAL TO THE FCST TEMPS/POPS THIS 3 DAY PERIOD. YDY THE ECMWF
WAS SOUTH BUT NO LONGER AND THIS IS A MUCH FIT FOR THE MORE
CONSISTENT GEFS. SO WHILE I CONSIDER THIS STILL A LOW CONFIDENCE
FCST ON THE DETAILS....I HAD ENOUGH CONFIDENCE TO RAISE HPC POPS
BY 15 TO 20 PCT ON MONDAY/MONDAY NIGHT IN THE INSTABILITY BURST
AHEAD OF 850 VORT MAX THAT IS ISAACS REMNANTS.
GEFS HINTS THAT THIS COULD BE A PRODUCTIVE EVENT FOR US...ITS
00Z/28 ENSEMBLES WITH A 10 PCT CHC OF A 48 HR 4 INCH TOTAL IN THE
NORTHERN PART OF OUR FCST AREA BY 00Z TUESDAY /LABOR DAY EVENING/.
GEFS PWATS ARE MODELED TO BE PLUS 2SD AS IS THE WAA 850MB SLY FLOW
COMPONENT. EARLY BUT INTERESTING....ESPECIALLY WITH A POSSIBLE
QSTRY FRONT WITH WHICH TO INTERACT. IT SHOULD BE STATED THAT THE
12Z GEFS DOES NOT HAVE 48 HR 10 PCT PROB OF 4 INCHES FOR OUR AREA.
SINCE WE`RE TALKING DAY 5-6-7...PLENTY OF TIME FOR MODEL
ADJUSTMENTS.
&&
.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD WITH A MOSTLY
CLEAR SKY.
A NORTHWEST WIND AT 8 KNOTS OR LESS THIS EVENING SHOULD BECOME
MORE NORTHERLY FOR LATE TONIGHT AND WEDNESDAY MORNING BEFORE
BACKING TOWARD THE NORTHWEST AGAIN FOR WEDNESDAY AFTERNOON.
OUTLOOK...
WEDNESDAY NIGHT...VFR. ISOLATED PATCHY MVFR FOG POSSIBLE LATE.
THURSDAY...ISOLATED PATCHY MVFR FOG POSSIBLE THROUGH 13Z AT THE
USUAL LOCATIONS...OTHERWISE VFR. WIND BECOMING LIGHT W...G UNDER
15 KTS.
FRIDAY...VFR. POSSIBLE MVFR FOG EARLY IN THE DAY. WSW G20 KTS
DURING THE DAY. LOW PROB ISOLATED SHOWER LATE AT NIGHT.
SATURDAY...VFR CONDITIONS ARE EXPECTED. THERE COULD BE WIDELY
SCATTERED SHOWER OR THUNDERSTORM...BUT CONFIDENCE IS BELOW
AVERAGE. W WIND TO START MAY SHIFT TO NW AND G UNDER 20 KTS.
SUNDAY...CONFIDENCE IS BELOW AVERAGE AND SO THE FCST IS VFR OCNL
CIGS BUT A POSSIBILITY OF MVFR CONDS IN SHOWERS AT NIGHT AND ESE
FLOW G UNDER 20 KTS.
&&
.MARINE...
SUB-ADVISORY CONDITIONS ARE EXPECTED TO CONTINUE ON THE AREA
WATERS.
A REINFORCING COLD FRONT WILL CROSS THE WATERS IN THE NEXT 2
HOURS. BEHIND THE FRONT...THE LOW LEVEL PUSH OF COOL AIR OVER THE
RELATIVELY WARM WATER SHOULD RESULT IN EFFICIENT MOMENTUM
TRANSFER. THE LATEST HRRR AND RAP OUTPUT SHOWS THE POTENTIAL FOR
25 KNOT GUSTS ACROSS THE SOUTHERN OCEAN WATERS AND LOWER DELAWARE
BAY BETWEEN 0900 AND 1100 UTC. NO HEADLINES YET AS THERE IS NOT
ENOUGH CONFIDENCE IN OCCURRENCE...BUT TRENDS WILL BE WATCHED FOR
GUSTS AS WE APPROACH 1000 UTC.
HIGH PRESSURE WILL BUILD IN FROM THE WEST ON WEDNESDAY WITH THE
GRADIENT GRADUALLY RELAXING THROUGH THE DAY. SEAS WILL REMAIN
FROM 3 TO 4 FEET ON THE OCEAN THROUGH WEDNESDAY.
OUTLOOK...
WEDNESDAY NIGHT THROUGH SUNDAY. NO HEADLINES ANTICIPATED.
FRIDAY AFTERNOON...THERE IS A SMALL CHANCE WE`LL NEED A WLY FLOW
SCA HEADLINE WITH GUSTY NEAR SHORE WINDS TO NEAR 25 KNOTS BUT FOR
NOW NOT PLAYING THIS UP.
SUNDAY...DEPENDING ON THE HIGH POSITION WITH RESPECT TO THE
MODELED ONCOMING ISAAC REMNANTS...WE MAY DEVELOP AN ESE SCA FLOW.
&&
.RIP CURRENTS...
IT APPEARS AS THOUGH THERE WILL BE A MODERATE RISK OF RIP
CURRENTS AGAIN FOR WEDNESDAY. WE ARE EXPECTING 2 TO 4 FOOT WAVES
WITH A 10 SECOND PERIOD. A NORTHERLY WIND AT 10 TO 15 MPH MAY
CONTRIBUTE TO ENHANCING THE RIP CURRENT RISK.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DRAG
NEAR TERM...IOVINO
SHORT TERM...MEOLA
LONG TERM...DRAG
AVIATION...DRAG/IOVINO
MARINE...DRAG/HAYES/MEOLA
RIP CURRENTS...IOVINO
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
515 PM EDT MON AUG 27 2012
.SYNOPSIS...
21Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS OUR FORECAST AREA RESIDES
BETWEEN THE UPPER LOW FEATURE OF TROPICAL STORM ISAAC AND AN UPPER
RIDGE OFF THE SOUTHEAST CONUS. WV IMAGERY SHOWS A DEEP SOUTHERLY
FLOW ON THE EASTERN CIRCULATION OF ISAAC MOVING OVER THE FL
PENINSULA. HOWEVER...DESPITE THIS TROPICAL CONNECTION WE HAVE SEEN
SOME FAIRLY SIGNIFICANT DRYING THROUGH THE COLUMN AS A WHOLE WITH A
DROP IN PW FROM THE 12Z SOUNDING FROM 2.6" DOWN TO 1.8". MUCH OF
THIS DRYING HAS OCCURRED ABOVE 500MB AND THE MOIST COLUMN BELOW THIS
LEVEL IS STILL QUITE SUPPORTIVE OF SHALLOW CONVECTION.
AT THE SURFACE...THE PRESSURE GRADIENT HAS REALLY TIGHTENED ACROSS
THE REGION IN THE PAST SEVERAL HOURS. THIS IS PARTLY A RESULT OF THE
DEEPENING OCCURRING WITHIN TROPICAL STORMS ISAAC (CENTRAL PRESSURE
IS DOWN AROUND 981MB). IN ADDITION...SIGNIFICANT CONVECTION ALONG
THE FL EAST COAST TODAY HAS SET UP A COLD POOL AND ASSOCIATED
MESO-HIGH FEATURE TO OUR WEST. CONDITIONS HAVE BECOME RATHER GUSTY
BETWEEN THESE 2 FEATURES AND SHOULD CONTINUE SO FOR AT LEAST SEVERAL
MORE HOURS.
WE DID NOT SEE THE DOMINANT BANDING OF CONVECTION SEEN OVER TOWARD
THE EAST COAST TODAY...BUT THE BREAKS IN THE CLOUD COVER CERTAINLY
RAISED THE INSTABILITY AND RESULTED IN SCT-NMRS SHALLOW
SHOWERS/STORMS THROUGH THE AFTERNOON. REGIONAL RADARS CONTINUE TO
SHOW THE DEVELOPMENT OF THESE CELLS AND WILL KEEP POPS IN THE LIKELY
RANGE THROUGH THE EVENING HOURS.
&&
.SHORT TERM (TONIGHT THROUGH WEDNESDAY)...
TONIGHT...WITH THE LOSS OF DIURNAL HEATING WE SHOULD SLOWLY SEE A
RAMP DOWN IN THE WIND GUSTS...ESPECIALLY OVER THE LAND MASS...AND
ALSO A SLOW DECREASE IN THE COVERAGE OF SHOWERS AND STORMS. THE
MOIST ATMOSPHERE AND SOME GENERAL LOW LEVEL CONVERGENCE WILL KEEP AT
LEAST SOME ACTIVITY ROTATING SOUTH TO NORTH THROUGH THE OVERNIGHT.
HOWEVER...THE BEST CHANCES FOR THESE SHOWERS AFTER THE LATER EVENING
HOURS WILL BE OVER THE COASTAL LAND ZONES AND OVER THE COASTAL
WATERS.
TUESDAY...UPPER RIDGING TRYING TO BUILD IN FROM THE EAST WILL
SLOWLY INCREASE OUR HEIGHTS...HOWEVER THE DEEP SOUTH/SE FLOW WILL
HELP KEEP THE AIRMASS FAIRLY MOIST AND UNSTABLE. THE OVERALL
CONNECTION TO THE CIRCULATION OF ISAAC WILL BE DIMINISHING FOR OUR
AREA...BUT THE AVAILABLE MOISTURE WILL KEEP SHOWERS AND STORMS IN
THE FORECAST...AND RAIN CHANCES IN THE LIKELY RANGE. CERTAINLY
SHOULD NOT BE A WASHOUT OF A DAY BUT A CONTINUATION OF THE FAST
MOVING SOUTH TO NORTH CONVECTIVE CELLS IS EXPECTED. THE COMBINATION
OF THE ELEVATED SOUTHERLY FLOW AND SWELL PROPAGATING BACK TO THE
COAST FROM ISAAC WILL ONCE AGAIN RESULT IN A HIGH RISK OF RIP
CURRENTS ALONG AREA BEACHES FROM PINELLAS COUNTY SOUTHWARD ON
TUESDAY.
WEDNESDAY...ANOTHER DAY OF DEEP SOUTHERLY MOISTURE. GFS/ECMWF BOTH
SHOW A WEAK MID-LEVEL IMPULSE ROUNDING THE BASE OF THE UPPER RIDGE
AND APPROACHING THE NW CARRIBEAN/S FL PENINSULA. SOME WEAK SYNOPTIC
SUPPORT FROM THIS FEATURE ALONG WITH THE ABUNDANT COLUMN MOISTURE
SHOULD KEEP THE COVERAGE OF SHOWERS AND STORMS ABOVE NORMAL.
&&
.LONG TERM (THURSDAY THROUGH SUNDAY)...
ISAAC IS EXPECTED TO JUST HAVE MADE LANDFALL AS THE PERIOD BEGINS
AND THEN MEANDER NORTHWARD OVER THE NATIONS MID-SECTION. HIGH
PRESSURE OVER THE ATLANTIC RIDGES IN ACROSS FL...IN THE WAKE OF
ISAAC...EARLY IN THE PERIOD AND GETS REINFORCED BY HIGH PRESSURE
THAT BUILDS OVER THE MID-ATLANTIC STATES BY WEEKS END AND AND THEN
SHIFTS OUT OVER THE ATLANTIC DURING THE WEEKEND. THE FORECAST CAN
GRADUALLY RETURN TO NORMAL FOR LATE SUMMER WITH SCATTERED SHOWERS
AND THUNDERSTORMS...ALTHOUGH POPS WILL TEND DOWN BY THE WEEKEND.
TEMPERATURES WILL BE ABOUT NORMAL.
&&
.AVIATION
CONTINUED MVFR CEILINGS TODAY WITH SOME BRIEF IFR CEILINGS AND
PERHAPS VISIBILITIES IN RAIN BANDS. GUSTY WINDS TO 30 KNOTS OR MORE
POSSIBLE IN HEAVIER SHOWERS. EXPECT SOME SLOW IMPROVEMENT AFTER 02Z.
&&
.MARINE...
TROPICAL STORM ISAAC CONTINUES MOVING TO THE NORTHWEST TOWARD THE
NORTH-CENTRAL GULF OF MEXICO COASTLINE. ISAAC IS A LARGE STORM AND
HAZARDOUS CONDITIONS WILL CONTINUE OVER THE COASTAL WATERS AS LARGE
WAVES AND SWELLS MOVE ACROSS THE REGION. FOR ADDITIONAL INFORMATION
ON TROPICAL STORM ISAAC...SEE THE LATEST ADVISORIES BEING ISSUED BY
THE NATIONAL HURRICANE CENTER.
&&
.FIRE WEATHER...
DEEP SOUTHERLY FLOW WILL CONTINUE TO BRING ABUNDANT LOW LEVEL
MOISTURE AND ELEVATED RAIN CHANCES TO THE REGION. NO SIGNIFICANT
FIRE WEATHER CONCERNS ARE ANTICIPATED THROUGH AT LEAST THE MIDDLE OF
THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 78 88 78 89 / 60 60 40 60
FMY 78 89 77 90 / 60 60 40 60
GIF 77 90 75 91 / 50 70 30 60
SRQ 80 88 78 89 / 60 60 40 60
BKV 78 90 75 90 / 60 60 40 60
SPG 81 88 80 89 / 60 60 40 60
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...LAKE WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
CHARLOTTE-CITRUS-DESOTO-HARDEE-HERNANDO-HIGHLANDS-
HILLSBOROUGH-LEE-LEVY-MANATEE-PASCO-PINELLAS-POLK-
SARASOTA-SUMTER.
COASTAL FLOOD ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
CHARLOTTE-CITRUS-HERNANDO-HILLSBOROUGH-LEE-LEVY-
MANATEE-PASCO-PINELLAS-SARASOTA.
BEACH HAZARDS STATEMENT THROUGH TUESDAY AFTERNOON FOR
CHARLOTTE-HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA.
HIGH SURF ADVISORY UNTIL 4 PM EDT TUESDAY FOR CHARLOTTE-
HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA.
GULF WATERS...TROPICAL STORM WARNING FOR BONITA BEACH TO ENGLEWOOD OUT
20 NM-BONITA BEACH TO ENGLEWOOD OUT 20 TO 60 NM-
ENGLEWOOD TO TARPON SPRINGS OUT 20 NM-ENGLEWOOD TO
TARPON SPRINGS OUT 20 TO 60 NM-TARPON SPRINGS TO
SUWANNEE RIVER OUT 20 NM-TARPON SPRINGS TO SUWANNEE
RIVER OUT 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT TUESDAY FOR TAMPA BAY
WATERS.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
AVIATION...JILLSON
LONG TERM...RUDE
AREA FORECAST DISCUSSION
NWS LINCOLN IL
221 PM CDT MON AUG 27 2012
.DISCUSSION...
ISSUED 205 PM CDT MON AUG 27 2012
WEAK COOL FRONT HAS FINALLY PUSHED SOUTHEAST OF THE AREA WITH SOME
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS REDEVELOPING ALONG THE
BOUNDARY. FURTHER TO THE NORTH...MUCH DRIER AIR WAS WORKING SOUTH
INTO OUR AREA WITH DEW POINTS LOWERING INTO THE MIDDLE 50S ACROSS
NORTHERN ILLINOIS. EARLY AFTERNOON TEMPERATURES HAVE WARMED INTO
THE MID TO UPPER 80S WITH A SUN-CLOUD MIX.
SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT
FOG POTENTIAL TONIGHT ALONG WITH AFTERNOON TEMPERATURES THRU MOST
OF THIS WEEK THE MAIN FORECAST CHALLENGES.
WEAK FRONTAL SYSTEM THAT PUSHED ACROSS OUR AREA LATE LAST NIGHT
THROUGH THIS MORNING WILL CONTINUE TO DRIFT SOUTH OF THE FORECAST
AREA OVERNIGHT...WITH HIGH PRESSURE SETTLING IN FROM THE NW. THIS
FAIR WEATHER SYSTEM CONTINES TO FEED MUCH DRIER AIR SOUTH INTO
THE REGION BUT THE SIGNIFICANT RAINFALL OVER THE PAST 24 HOURS
ACROSS THE NORTH AND FAR SOUTH MAY PRODUCE SOME FOG BY TUESDAY
MORNING. WILL CONTINUE TO HOLD ON TO SOME FOG DEVELOPING LATE
TONIGHT AND INTO EARLY TUESDAY MORNING.
HIGH PRESSURE WILL THEN TAKE HOLD ACROSS THE MIDWEST BRINGING
SUNSHINE AND RATHER WARM TEMPERATURES AGAIN. MODELS CONTINUE TO
INDICATE A WEAK SHORTWAVE CURRENTLY PUSHING ACRS THE NORTHERN
ROCKIES EAST THRU THE PLAINS ON TUESDAY. SOME SCATTERED CONVECTION
WILL ACCOMPANY THE UPPER LEVEL WAVE LATE TUESDAY AND TUESDAY NIGHT
WITH SOME OF THE HI-RES CONVECTIVE ALLOWING MODELS BRINGING A
DECAYING BAND OF SHOWERS AND STORMS TO OUR NORTHWEST LATER TUESDAY
NIGHT. FORECAST SOUNDINGS CONTINUE TO INDICATE SOME VERY DRY AIR
IN PLACE AS THE SURFACE RIDGE REMAINS ANCHORED FROM CENTRAL LOWER
MICHIGAN SW THRU OUR FORECAST AREA TUESDAY NIGHT INTO WED MORNING.
OTHER THAN SOME RESIDUAL MID AND HIGH LEVEL CLOUDS TUESDAY NIGHT
WE ARE NOT EXPECTING ANY PRECIP WITH THIS UPPER WAVE.
THE SURFACE RIDGE AXIS WILL SHIFT SLOWLY TO THE EAST ON THURSDAY
WHICH WILL KEEP OUR AREA VERY WARM AND DRY ONCE AGAIN. THE NAM
850 MB TEMPERATURES BY THURSDAY AFTERNOON WILL BE 20 TO 22 DEG C
WHICH SHOULD HELP PUSH READINGS AT LEAST INTO THE UPPER 80S EAST
TO LOWER 90S WEST. CLOUD COVER WILL BE ON THE INCREASE THURSDAY
NIGHT ACROSS THE SOUTH AS THE REMNANTS OF ISAAC SLOWLY TRACK
NORTH INTO THE LOWER MISSISSIPPI VALLEY.
LONG TERM...FRIDAY THROUGH MONDAY
THE REMNANTS OF ISAAC AND ITS RAIN THREAT INTO THE HOLIDAY WEEKEND
WILL BE THE MAIN FORECAST COCERN THIS PERIOD.
ALTHOUGH MODELS WERE SHOWING BETTER AGREEMENT WITH THE FORECAST TRACK
OF ISAAC...THERE STILL IS QUITE A BIT OF UNCERTAINTY WITH RESPECT
TO THE TRACK AND SPEED OF THE SYSTEM AS IT HEADS NORTH INTO THE
UPPER LEVEL RIDGE OVER THE MIDWEST LATE THIS WEEK. THE NORTHERN
EDGE OF THE PRECIP SHIELD SHOULD GRADUALLY WORK ITS WAY NORTH INTO
SE IL FRIDAY AND CONTINUE TO SPREAD NORTH THROUGH FRIDAY NIGHT.
THE OFFICIAL TRACK ISSUED EARLY THIS AFTERNOON HAS THE SYSTEM JUST
NORTHWEST OF STL BY SATURDAY MORNING WHICH WOULD BRING RAIN TO MOST
OF THE CWA FOR A PORTION OF OUR HOLIDAY WEEKEND.
LATEST ECMWF HAS BROUGHT THE SYSTEM NORTH BUT KEEPS THE DEPRESSION
SOUTH OF STL BY SATURDAY MORNING...A SLOWER SOLUTION...AND THEN
TAKES THE SYSTEM BACK SOUTH THRU KY AND TN BY LATER SUNDAY. CONFIDENCE
ON ANY ONE OF THESE MODELS HANDLING THIS WARM CORE SYSTEM IS LOW AT
BEST SO WILL CONTINUE WITH CHANCE POPS IN THE GRIDS UNTIL WE SEE A
BIT MORE CONSISTENCY...WHICH MAY NOT BE UNTIL LATER THIS WEEK. WHAT
RAIN WE DO SEE STARTING ON FRIDAY SHOULD BEGIN TO PUSH AWAY DURING
THE DAY SUNDAY WITH SOME DRIER AIR SLATED TO MOVE INTO OUR AREA BY
THE END OF THE FORECAST PERIOD.
SMITH
&&
.AVIATION...
ISSUED 623 AM CDT MON AUG 27 2012
MAIN CONCERN AVIATION-WISE IS THE NEXT FEW HOURS. FAIRLY
WIDESPREAD MVFR/IFR CEILINGS OVER THE NORTHERN HALF OF ILLINOIS
INTO ADJACENT PARTS OF MISSOURI AND IOWA. HRRR CEILING GUIDANCE
SHOWING THIS SHOULD RAPIDLY BREAK UP BETWEEN ABOUT 14-17Z...
ALTHOUGH AREAS FROM KPIA-KCMI WHICH HAD HEAVY RAINFALL RECENTLY
MAY TAKE TOWARD THE END OF THAT TIME RANGE. HAVE SEEN SOME BRIEF
VISIBILITY REDUCTIONS BUT FOR THE MOST PART...THE DENSE FOG HAS
REMAINED TO THE NORTHWEST IN AREAS THAT CLEARED OUT FOR A TIME
EARLIER IN THE NIGHT. ONCE THE CLOUDS BREAK UP BY LATE MORNING...
VFR CONDITIONS SHOULD PREVAIL THE REMAINDER OF THE TAF PERIOD. THE
ONLY EXCEPTION WOULD BE SOME PATCHY FOG THAT MAY FORM LATE
TONIGHT AS WINDS BECOME LIGHT...WITH THE PRIMARY CONCERN IN AREAS
THAT HAD HEAVY RAIN. AT THE MOMENT...WILL ONLY MENTION THIS AT KCMI.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1044 AM CDT MON AUG 27 2012
.DISCUSSION...
ISSUED 1045 AM CDT MON AUG 27 2012
A FEW MINOR ADJUSTMENTS TO THE FORECAST TODAY...LIKE CONTINUE
A SLIGHT CHANCE OF SHOWERS/THUNDERSTORMS IN FAR SE IL UNTIL MID
AFTERNOON AND INCREASING CLOUD COVER OVER SE IL INTO EARLY
AFTERNOON. HIGHS MAINLY IN THE MID 80S...THOUGH RANGING FROM THE
LOWER 80S NEAR THE INDIANA BORDER...TO THE UPPER 80S OVER WEST
CENTRAL AND NW IL WHERE MORE SUNSHINE EXPECTED TODAY. WINDS NNW AT
5 TO 15 MPH OVER CENTRAL IL TO SPREAD INTO SE IL TOO THIS
AFTERNOON BEHIND COLD FRONT.
LATE MORNING SURFACE MAP SHOWS WEAK 1015 MB LOW PRESSURE ALONG THE
IN/OH/MI BORDER WITH A COLD FRONT EXTENDING SW THROUGH CENTRAL
INDIANA INTO SE IL NEAR I-70 AND INTO SE MO. ISOLATED SHOWERS
OCCUR ALONG AND AHEAD OF THIS COLD FRONT FROM I-70 SE LATE THIS
MORNING AND SPREADING EASTWARD. HIGH RESOLUTION MODELS BRING COLD
FRONT SE TO THE OHIO RIVER BY 00Z/7 PM TAKING ITS ISOLATED
CONVECTION SE OF LAWRWENCEVILLE BY MID AFTERNOON. HUMID AIRMASS
CURRENTLY IN PLACE OVER CENTRAL/SE IL WITH DEWPOINTS IN THE UPPER
60S AND LOWER 70S CENTRAL IL AND LOW TO MID 70S IN SE IL WILL
GRADUALLY LOWER TO THE LOWER 60S IN CENTRAL IL AND UPPER 60S IN SE
IL BY LATE TODAY WITH NNW WINDS 5-15 MPH. LOW CLOUDS FROM I-55 SE
WILL ALSO GRADUALLY DECREASE FROM NW TO SE DURING THE AFTERNOON AS
SKIES BECOME MOSTLY SUNNY...THOUGH STAYING CLOUDIER LONGER IN SE IL.
KH
&&
.AVIATION...
ISSUED 623 AM CDT MON AUG 27 2012
MAIN CONCERN AVIATION-WISE IS THE NEXT FEW HOURS. FAIRLY
WIDESPREAD MVFR/IFR CEILINGS OVER THE NORTHERN HALF OF ILLINOIS
INTO ADJACENT PARTS OF MISSOURI AND IOWA. HRRR CEILING GUIDANCE
SHOWING THIS SHOULD RAPIDLY BREAK UP BETWEEN ABOUT 14-17Z...
ALTHOUGH AREAS FROM KPIA-KCMI WHICH HAD HEAVY RAINFALL RECENTLY
MAY TAKE TOWARD THE END OF THAT TIME RANGE. HAVE SEEN SOME BRIEF
VISIBILITY REDUCTIONS BUT FOR THE MOST PART...THE DENSE FOG HAS
REMAINED TO THE NORTHWEST IN AREAS THAT CLEARED OUT FOR A TIME
EARLIER IN THE NIGHT. ONCE THE CLOUDS BREAK UP BY LATE MORNING...
VFR CONDITIONS SHOULD PREVAIL THE REMAINDER OF THE TAF PERIOD. THE
ONLY EXCEPTION WOULD BE SOME PATCHY FOG THAT MAY FORM LATE
TONIGHT AS WINDS BECOME LIGHT...WITH THE PRIMARY CONCERN IN AREAS
THAT HAD HEAVY RAIN. AT THE MOMENT...WILL ONLY MENTION THIS AT KCMI.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 320 AM CDT MON AUG 27 2012
WEAK FLOW ACROSS THE MIDWEST THIS MORNING...WITH PRECIP ALONG A
WEAKENING BOUNDARY AT THE SFC AS THE FORWARD PROGRESSION SLOWS AS
ITS APPROACHING THE OHIO RIVER VALLEY. LINGERING PRECIP IN SRN
TIER OF CWA THIS MORNING...AND FIRST ISSUE FOR THE FORECAST IS THE
CLEARING OF THIS RAIN TODAY...AND ITS IMPACT ON TEMPERATURES THIS
AFTERNOON. BEYOND THAT AND THE POTENTIAL FOR FOG IN THE WAKE OF
ALL OF SUNDAYS RAINFALL...THE MAIN ISSUE FOR THE FORECAST IS IN
THE EXTENDED WITH REGARDS TO THE REMNANTS OF ISAAC AND POTENTIAL
MOISTURE TRANSPORT.
SHORT TERM...TODAY AND TOMORROW...
SLOWING BOUNDARY KEEPING POPS IN FOR THIS MORNING...MAINLY ALONG
AND SOUTH OF INTERSTATE 70 FOR THE BEST POPS. MOST MODELS SLIGHTLY
OVERDONE IN THE OVERNIGHT PRECIP...INCLUDING THE HIGH RES MODELS
LIKE THE 4KM WRF WHICH EVEN ANTICIPATED THE SLIGHT STRENGTHENING
OF SOME OF THE RAINFALL ALONG AND SOUTH OF INTERSTATE 70 AFTER
06Z. HOWEVER...EVEN SO...MOST MODELS CLEARING AFTER 18Z AND WILL
KEEP THE GRIDS SIMPLE AND FOLLOW THAT TREND. CLOUDINESS IN THE SE
WILL KEEP THE TEMPS A BIT LOWER THIS AFTERNOON...WHEREAS THE NW
AND WEST WILL HAVE A CHANCE TO MAX OUT IN THE UPPER 80S. REAL
QUESTION FOR THE SHORT TERM WILL BE THE AMOUNT OF MIXING THAT GETS
INTO THE REGION BY THIS EVENING. MUCH DRIER AIR IS CONTAINED
BEHIND THE SECONDARY BOUNDARY WELL TO THE NW FROM SD TO SRN MN.
NAM BRINGS IN AFTERNOON CROSSOVER TEMPS DOWN INTO THE 50S...AND THINK
THAT IS HIGHLY UNLIKELY CONSIDERING THE SOAKING OF YESTERDAY AND
THE SLOWER RETREAT OF THE CLOUDS TODAY. PUTTING IN PATCHY FOG FOR
TOMORROW EARLY MORNING AT THE VERY LEAST...AND WILL HAVE TO KEEP
AN EYE ON DWPTS FOR THIS AFTERNOON AS TO THE EXPANSE OF FOG
POTENTIAL.
LONG TERM...WEDNESDAY THROUGH SUNDAY...
RAIN POTENTIAL IN THE EXTENDED IS ENTIRELY BASED ON THE
TRACK/MOISTURE TRANSPORT FROM TS ISAAC AND WHERE IT MAKES
LANDFALL. AS A RESULT...THE POPS IN THE EXTENDED ARE A BIT
PRECARIOUS. LOOSELY STATED...CHANCES EXTEND FROM FRIDAY THROUGH
SUNDAY...WITH THE BEST CHANCES MAINLY IN THE SOUTHERN HALF OF THE
STATE. THAT BEING SAID...THINK THE GFS AND TO SOME EXTENT THE 00Z
ECMWF ARE A BIG HASTY IN BRINGING THE SYSTEM UP HERE SO QUICKLY.
MOVING THE TROPICAL SYSTEM INTO THE RATHER EXPANSIVE RIDGE IS
LIKELY TO SLOW IT SOMEWHAT...AND DISRUPT THE MOISTURE ADVECTION
WITH THE VOLUME OF DRY AIR AVAILABLE TO EAT AWAY AT THE RH.
HOWEVER...THE GFS MAINTAINS A CYCLONE DYNAMIC AND SHAPE EVEN TO
THE QPF/CONVECTIVE FIELDS. CONCERNED THAT ITS OVERDONE A BIT...AND
TRYING TO SCALE BACK THE MASSIVE POPS. NOT ONLY ARE THE
OPERATIONAL MODELS TREATING A TROPICAL...THEN EXTRA TROPICAL
SYSTEM LIKE A MID LATITUDE CYCLONE...BUT THERE IS SO MUCH SPREAD IN
THE LANDFALL FORECASTS/TRACKS FOR THE FORECAST THAT CALLING
CERTAINTY AT THIS POINT IS A BIT OPTIMISTIC. FORECAST IS
RELATIVELY CONSERVATIVE...WITH A PUSH FOR A SLIGHTLY DELAYED
PRECIP EVENT SHOULD THE MOISTURE MATERIALIZE.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
623 AM CDT MON AUG 27 2012
.DISCUSSION...
ISSUED 320 AM CDT MON AUG 27 2012
WEAK FLOW ACROSS THE MIDWEST THIS MORNING...WITH PRECIP ALONG A
WEAKENING BOUNDARY AT THE SFC AS THE FORWARD PROGRESSION SLOWS AS
ITS APPROACHING THE OHIO RIVER VALLEY. LINGERING PRECIP IN SRN
TIER OF CWA THIS MORNING...AND FIRST ISSUE FOR THE FORECAST IS THE
CLEARING OF THIS RAIN TODAY...AND ITS IMPACT ON TEMPERATURES THIS
AFTERNOON. BEYOND THAT AND THE POTENTIAL FOR FOG IN THE WAKE OF
ALL OF SUNDAYS RAINFALL...THE MAIN ISSUE FOR THE FORECAST IS IN
THE EXTENDED WITH REGARDS TO THE REMNANTS OF ISAAC AND POTENTIAL
MOISTURE TRANSPORT.
SHORT TERM...TODAY AND TOMORROW...
SLOWING BOUNDARY KEEPING POPS IN FOR THIS MORNING...MAINLY ALONG
AND SOUTH OF INTERSTATE 70 FOR THE BEST POPS. MOST MODELS SLIGHTLY
OVERDONE IN THE OVERNIGHT PRECIP...INCLUDING THE HIGH RES MODELS
LIKE THE 4KM WRF WHICH EVEN ANTICIPATED THE SLIGHT STRENGTHENING
OF SOME OF THE RAINFALL ALONG AND SOUTH OF INTERSTATE 70 AFTER
06Z. HOWEVER...EVEN SO...MOST MODELS CLEARING AFTER 18Z AND WILL
KEEP THE GRIDS SIMPLE AND FOLLOW THAT TREND. CLOUDINESS IN THE SE
WILL KEEP THE TEMPS A BIT LOWER THIS AFTERNOON...WHEREAS THE NW
AND WEST WILL HAVE A CHANCE TO MAX OUT IN THE UPPER 80S. REAL
QUESTION FOR THE SHORT TERM WILL BE THE AMOUNT OF MIXING THAT GETS
INTO THE REGION BY THIS EVENING. MUCH DRIER AIR IS CONTAINED
BEHIND THE SECONDARY BOUNDARY WELL TO THE NW FROM SD TO SRN MN.
NAM BRINGS IN AFTERNOON CROSSOVER TEMPS DOWN INTO THE 50S...AND THINK
THAT IS HIGHLY UNLIKELY CONSIDERING THE SOAKING OF YESTERDAY AND
THE SLOWER RETREAT OF THE CLOUDS TODAY. PUTTING IN PATCHY FOG FOR
TOMORROW EARLY MORNING AT THE VERY LEAST...AND WILL HAVE TO KEEP
AN EYE ON DWPTS FOR THIS AFTERNOON AS TO THE EXPANSE OF FOG
POTENTIAL.
LONG TERM...WEDNESDAY THROUGH SUNDAY...
RAIN POTENTIAL IN THE EXTENDED IS ENTIRELY BASED ON THE
TRACK/MOISTURE TRANSPORT FROM TS ISAAC AND WHERE IT MAKES
LANDFALL. AS A RESULT...THE POPS IN THE EXTENDED ARE A BIT
PRECARIOUS. LOOSELY STATED...CHANCES EXTEND FROM FRIDAY THROUGH
SUNDAY...WITH THE BEST CHANCES MAINLY IN THE SOUTHERN HALF OF THE
STATE. THAT BEING SAID...THINK THE GFS AND TO SOME EXTENT THE 00Z
ECMWF ARE A BIG HASTY IN BRINGING THE SYSTEM UP HERE SO QUICKLY.
MOVING THE TROPICAL SYSTEM INTO THE RATHER EXPANSIVE RIDGE IS
LIKELY TO SLOW IT SOMEWHAT...AND DISRUPT THE MOISTURE ADVECTION
WITH THE VOLUME OF DRY AIR AVAILABLE TO EAT AWAY AT THE RH.
HOWEVER...THE GFS MAINTAINS A CYCLONE DYNAMIC AND SHAPE EVEN TO
THE QPF/CONVECTIVE FIELDS. CONCERNED THAT ITS OVERDONE A BIT...AND
TRYING TO SCALE BACK THE MASSIVE POPS. NOT ONLY ARE THE
OPERATIONAL MODELS TREATING A TROPICAL...THEN EXTRA TROPICAL
SYSTEM LIKE A MID LATITUDE CYCLONE...BUT THERE IS SO MUCH SPREAD IN
THE LANDFALL FORECASTS/TRACKS FOR THE FORECAST THAT CALLING
CERTAINTY AT THIS POINT IS A BIT OPTIMISTIC. FORECAST IS
RELATIVELY CONSERVATIVE...WITH A PUSH FOR A SLIGHTLY DELAYED
PRECIP EVENT SHOULD THE MOISTURE MATERIALIZE.
HJS
&&
.AVIATION...
ISSUED 623 AM CDT MON AUG 27 2012
MAIN CONCERN AVIATION-WISE IS THE NEXT FEW HOURS. FAIRLY
WIDESPREAD MVFR/IFR CEILINGS OVER THE NORTHERN HALF OF ILLINOIS
INTO ADJACENT PARTS OF MISSOURI AND IOWA. HRRR CEILING GUIDANCE
SHOWING THIS SHOULD RAPIDLY BREAK UP BETWEEN ABOUT 14-17Z...
ALTHOUGH AREAS FROM KPIA-KCMI WHICH HAD HEAVY RAINFALL RECENTLY
MAY TAKE TOWARD THE END OF THAT TIME RANGE. HAVE SEEN SOME BRIEF
VISIBILITY REDUCTIONS BUT FOR THE MOST PART...THE DENSE FOG HAS
REMAINED TO THE NORTHWEST IN AREAS THAT CLEARED OUT FOR A TIME
EARLIER IN THE NIGHT. ONCE THE CLOUDS BREAK UP BY LATE MORNING...
VFR CONDITIONS SHOULD PREVAIL THE REMAINDER OF THE TAF PERIOD. THE
ONLY EXCEPTION WOULD BE SOME PATCHY FOG THAT MAY FORM LATE
TONIGHT AS WINDS BECOME LIGHT...WITH THE PRIMARY CONCERN IN AREAS
THAT HAD HEAVY RAIN. AT THE MOMENT...WILL ONLY MENTION THIS AT KCMI.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1038 AM EDT MON AUG 27 2012
.Forecast Update...
Issued at 1035 AM EDT Mon Aug 27 2012
The cold front is currently situated along a line from northeastern
Indiana to southern Illinois to southeastern Missouri. Showers have
begun to move into our southern Indiana counties this morning with
more scattered development to the west. Currently there is little
lightning associated with this convection, so will continue to
mention scattered showers today with isolated thunderstorms for now.
Minor tweaks were made to the current grids and expected pop trends,
but percentages will remain in the same range. Updates are already
out.
&&
.Short Term (Today - Tuesday)...
Issued at 250 AM EDT Mon Aug 27 2012
A sfc cold front and upper trough stretched from the Great Lakes
through Illinois to Oklahoma as of 630Z this morning. Along this
front, showers with embedded t-storms were noted in radar imagery.
These features along with convection will continue to move eastward
into our area today. A few showers have already been noted in
Dubois County, Indiana early this morning. We can expect to see
continued isld activity through sunrise. After sunrise, the line of
scattered showers with some t-storms will make its way into our NW
forecast area and continue to travel ESE throughout the day. Thus,
most locations over southern Indiana and central Kentucky can expect
to see at least a brief shower at some point during the day and
tonight. However, QPF amounts should be under a tenth of an inch
for most locations. A few locations that see a t-storm may get a
quarter inch of rain. Any t-storms that develop should be garden
variety type storms with the main threats being locally heavy
rainfall, brief gusty winds, and cloud to ground lightning.
The front should pass through the area this evening slowly ending
any left over shower activity from NW to SE tonight over most
locations. The front does look to stall over south central KY Tues
morning so will keep low POPs in over this region through 18Z Tues.
Temperatures should range from the mid 80s over southern Indiana to
around 90 over south central KY for highs today. The hotter temps
will occur in locations over the south that will be the last to
receive rain/clouds from the approaching front/trough. Lows tonight
should be in the mid 60s to around 70. If southern Indiana or
northern KY clear out quick enough behind the front, light fog may
be possible tonight. For Tues, expect gradually clearing skies from
N to S with highs in the mid to upper 80s.
.Long Term (Tuesday Night - Sunday)...
Issued at 250 AM EDT Mon Aug 27 2012
Tropical cyclone Isaac is forecast to be entering the north central
Gulf coast at the start of this period, which should keep all
moisture south of the region Tuesday night through at least late
afternoon Thursday. Beyond that, models continue to have trouble
dealing with where the remnants of Isaac will end up. Most of the
models continue to show a narrow ridge getting squeezed into the
Midwest over the top of these remnants, in a Rex block fashion. This
would mean we can expect some slower movement with this system.
That small ridge looks to get forced into the Mid Atlantic region
Friday night on, which should allow the moisture to surge in here
and bring in better rain chances. Still lower than normal confidence
in this solution given the potential for a slower moving storm than
what the models are showing. The AllBlend solution for pops actually
looks pretty good with this scenario...having low end chances
Thursday night, then going to the 50 percent range Saturday into
Sunday. Keep your fingers crossed that we can get some of this rain
to help the drought situation.
Dry air over the region early on will mean a chance for the normally
cooler spots to get down to around 60 Wednesday and Thursday
mornings. Northerly winds will combat otherwise clear skies for
highs each day, so thinking readings will stay in the mid/upper 80s.
Cloud cover and moisture will limit the diurnal range the rest of
the period, with highs in the 80s and lows around 70.
&&
.Aviation (12Z TAF issuance)...
Issued at 655 AM EDT Mon Aug 27 2012
Main TAF concerns will be arrival of showers into the TAF sites this
afternoon. Convection along and ahead of a sfc cold front and upper
level trough will be entering the area this afternoon. 8Z RAP and
6Z NAM4 have a good handle on current convection and sfc features so
will lean toward these models. With these solns in mind, delayed
VCSH in the TAFs till 16Z at SDF, 19Z at LEX, and 21Z at BWG.
Models indicate a line of scattered garden variety showers with some
embedded t-storms. Thunder does not look likely for the TAFs at
this point. Winds should remain calm or SSE through the early
morning hours, then veer to the SWW for late morning and early
afternoon as the front approaches. The fropa looks to occur this
evening with winds shifting to the NWN after 3-4Z and shower chances
ending. Light br or low cigs may occur close to the front Tues
morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........EER
Short Term.......AMS
Long Term........RJS
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
655 AM EDT MON AUG 27 2012
...Updated Aviation Discussion...
.Forecast Update...
Issued at 635 AM EDT Mon Aug 27 2012
Downgraded t-storm chances to isld today. The 6Z NAM and 8Z RAP
really depict what`s left of convection along the front falling
apart throughout the day as it crosses our area. Was on the fence
about isld or sct t-storm chances for the 4am forecast package.
Upstream obs and latest model guidance points toward only isld
storms if that today so will update the forecast.
&&
.Short Term (Today - Tuesday)...
Issued at 250 AM EDT Mon Aug 27 2012
A sfc cold front and upper trough stretched from the Great Lakes
through Illinois to Oklahoma as of 630Z this morning. Along this
front, showers with embedded t-storms were noted in radar imagery.
These features along with convection will continue to move eastward
into our area today. A few showers have already been noted in
Dubois County, Indiana early this morning. We can expect to see
continued isld activity through sunrise. After sunrise, the line of
scattered showers with some t-storms will make its way into our NW
forecast area and continue to travel ESE throughout the day. Thus,
most locations over southern Indiana and central Kentucky can expect
to see at least a brief shower at some point during the day and
tonight. However, QPF amounts should be under a tenth of an inch
for most locations. A few locations that see a t-storm may get a
quarter inch of rain. Any t-storms that develop should be garden
variety type storms with the main threats being locally heavy
rainfall, brief gusty winds, and cloud to ground lightning.
The front should pass through the area this evening slowly ending
any left over shower activity from NW to SE tonight over most
locations. The front does look to stall over south central KY Tues
morning so will keep low POPs in over this region through 18Z Tues.
Temperatures should range from the mid 80s over southern Indiana to
around 90 over south central KY for highs today. The hotter temps
will occur in locations over the south that will be the last to
receive rain/clouds from the approaching front/trough. Lows tonight
should be in the mid 60s to around 70. If southern Indiana or
northern KY clear out quick enough behind the front, light fog may
be possible tonight. For Tues, expect gradually clearing skies from
N to S with highs in the mid to upper 80s.
.Long Term (Tuesday Night - Sunday)...
Issued at 250 AM EDT Mon Aug 27 2012
Tropical cyclone Isaac is forecast to be entering the north central
Gulf coast at the start of this period, which should keep all
moisture south of the region Tuesday night through at least late
afternoon Thursday. Beyond that, models continue to have trouble
dealing with where the remnants of Isaac will end up. Most of the
models continue to show a narrow ridge getting squeezed into the
Midwest over the top of these remnants, in a Rex block fashion. This
would mean we can expect some slower movement with this system.
That small ridge looks to get forced into the Mid Atlantic region
Friday night on, which should allow the moisture to surge in here
and bring in better rain chances. Still lower than normal confidence
in this solution given the potential for a slower moving storm than
what the models are showing. The AllBlend solution for pops actually
looks pretty good with this scenario...having low end chances
Thursday night, then going to the 50 percent range Saturday into
Sunday. Keep your fingers crossed that we can get some of this rain
to help the drought situation.
Dry air over the region early on will mean a chance for the normally
cooler spots to get down to around 60 Wednesday and Thursday
mornings. Northerly winds will combat otherwise clear skies for
highs each day, so thinking readings will stay in the mid/upper 80s.
Cloud cover and moisture will limit the diurnal range the rest of
the period, with highs in the 80s and lows around 70.
&&
.Aviation (12Z TAF issuance)...
Issued at 655 AM EDT Mon Aug 27 2012
Main TAF concerns will be arrival of showers into the TAF sites this
afternoon. Convection along and ahead of a sfc cold front and upper
level trough will be entering the area this afternoon. 8Z RAP and
6Z NAM4 have a good handle on current convection and sfc features so
will lean toward these models. With these solns in mind, delayed
VCSH in the TAFs till 16Z at SDF, 19Z at LEX, and 21Z at BWG.
Models indicate a line of scattered garden variety showers with some
embedded t-storms. Thunder does not look likely for the TAFs at
this point. Winds should remain calm or SSE through the early
morning hours, then veer to the SWW for late morning and early
afternoon as the front approaches. The fropa looks to occur this
evening with winds shifting to the NWN after 3-4Z and shower chances
ending. Light br or low cigs may occur close to the front Tues
morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS
Short Term.......AMS
Long Term........RJS
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
635 PM EDT MON AUG 27 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL APPROACH TONIGHT AND CROSS THE AREA EARLY
TUESDAY MORNING. HIGH PRESSURE MOVING IN FROM THE WEST WILL BUILD
INTO THE EAST COAST WEDNESDAY INTO THURSDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
UPDATE...ADJUSTED THE POPS INITIALLY TO REFLECT THE LATEST RADAR
TRENDS AND THEN BLENDED IN THE NAM12 WHICH APPEARS TO BE IN LINE
W/THE RADAR OF WIDELY SCATTERED SHOWERS AND ISOLD TSTMS THIS
EVENING. THE THINKING HERE IS THAT SHOWERS WILL FILL IN LATER
TONIGHT THROUGH EARLY TUESDAY MORNING AS THE FRONT APCHS W/POTENT
UPPER VORT MAX. KEPT DAYCREW`S POPS AFTER 06Z WHICH REFLECTS THIS
WELL ATTM. HEAVY RAFL A GOOD BET AND DAYCREW HAS THIS HANDLED
NICELY AS THE LATEST BUFKIT PROFILES INDICATE HEAVY RAFL POTENTIAL
W/WARM CLOUD PROCESSES.
FOG LOOKS LIKE A POTENTIAL FOR INTERIOR DOWNEAST AND THE COAST AS
LATEST SOUNDINGS INDICATE THIS WELL W/SSW FLOW OFF THE OCEAN.
TWEAKED 18-00Z QPF USING LATEST OBS AND RUC ANALYSIS. QPF WILL
INCREASE AS WELL LATER TONIGHT. NO OTHER CHANGES ATTM.
PREVIOUS DISCUSSION...
AN AREA OF PVA AND UNSTABLE AIR AHEAD OF A STRONG COLD FRONT WILL
PRODUCE SHOWERS AND THUNDERSTORMS TONIGHT. THE SHOWERS WILL SPREAD
SOUTHWARD TOWARDS BANGOR LATER TONIGHT. THERE IS A VOLATILE
MIXTURE OF THE UNUSUALLY WARM AND HUMID AIR MASS AHEAD OF THE
FRONT WITH COOL AND DRY CANADIAN AIR BEHIND THE FRONT. THIS CLASH COULD
ALLOW SHOWERS TOWARDS THE CROWN OF MAINE TO PRODUCE SOME FAIRLY
IMPRESSIVE PRECIPITATION TOTAL..REACHING UP TO AN INCH BEFORE THE
FRONT CROSSES TOMORROW. A DEEP WARM CLOUD LAYER OVER 11000
FEET...A STRONG LLJ AND PW NEARLY 2 INCHES WILL INCREASE THE ODDS
OF LOCALLY HEAVY RAINFALL TONIGHT. THE FRONT WILL SLOWLY DRAG
THROUGH THE STATE TONIGHT AND FINALLY MOVE OFF THE COAST TUESDAY
AFTERNOON. WITH THE PRECIPITATION AND LOW LEVEL MOISTURE PRODUCING
WIDESPREAD LOW CLOUDINESS BY LATER TONIGHT...LOWS WILL ONLY DROP
TO THE LOW TO MID 60S. WITH STRONG COLD AIR ADVECTION BEHIND THE
FRONT...HIGHS TUESDAY WILL ONLY REACH THE UPPER 60S TO LOW 70S
NORTH AND MID 70S DOWN EAST. HUMIDITY WILL DROP MARKEDLY FROM
TODAY`S READINGS IN THE AIR MASS BEHIND THE FRONT THAT WILL
PROVIDE A HINT OF FALL.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
COOLER AIR PUSHING INTO THE AREA AHEAD OF HIGH PRESSURE MOVING INTO
THE GREAT LAKES WILL BRING A MOSTLY CLEAR...COOL AND DRY NIGHT
TUESDAY NIGHT. THE HIGH WILL BRING A MOSTLY CLEAR AND COOL MORNING
THROUGHOUT THE REGION WEDNESDAY MORNING. A WEAK WEATHER DISTURBANCE
SLIDING IN FROM THE NORTHWEST ON WEDNESDAY WILL CARRY A BIT OF
MOISTURE WITH IT. THE MOISTURE WILL COME AS A FUNCTION OF SOME
WARM ADVECTION CIRCULATING IN FROM THE WEST JUST NORTH OF THE
HIGH PRESSURE SYSTEM. THIS WILL BRING A MOSTLY CLOUDY MIDDAY AND
AFTERNOON OVER THE NORTH WEDNESDAY WHILE DOWNEAST AREAS REMAIN
SUNNY TO PARTLY CLOUDY. CLOUDS WILL REMAIN ACROSS THE NORTH
THURSDAY NIGHT INTO FRIDAY WHILE DOWNEAST REMAINS PARTLY CLOUDY.
WARM ADVECTION MOISTURE NORTH OF THE HIGH AND JUST SOUTH OF A
SMALL LOW MOVING ACROSS CENTRAL CANADA MAY PROVIDE ENOUGH MOISTURE
TO PRODUCE A FEW SHOWERS OVER THE FAR NORTH THURSDAY AFTERNOON.
TEMPS DURING THE MID WEEK PERIOD WILL BE NEAR...TO JUST A COUPLE
DEGREES BELOW NORMAL FOR LATE AUGUST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
WEAK FRONTAL BOUNDARY DRAPED ACROSS NORTHERN FORECAST AREA WILL
BEGIN TO SLOWLY PUSH NORTH OF ST JOHN VALLEY BY EARLY SATURDAY.
CHANCE OF RAINSHOWERS ACROSS MOST OF AROOSTOOK COUNTY THROUGH
SATURDAY...SLIGHT CHANCE ELSEWHERE. COLD FRONT WILL THEN MOVE IN
FROM QUEBEC THROUGH DAY SATURDAY WITH SHOWERS. COLD FRONT WILL
CLEAR ALL OF FORECAST AREA BY SUNDAY MORNING FOR A SUNNY AND DRY DAY
WITH A HINT OF EARLY FALL IN THE AIR. WEAK SHORT WAVE IN NORTHWEST
UPPER FLOW WILL AGAIN BRING SLIGHT CHANCE OF SHOWERS IN
NORTHWESTERN ZONES MONDAY AFTERNOON. TEMPERATURE WISE LOOK FOR
DAYTIME HIGHS IN LOW TO MID 70S NORTH AND NEAR 80 DOWNEAST ON
FRIDAY THEN MID TO UPPER 60S NORTH WITH MID 70S DOWNEAST SATURDAY
THROUGH MONDAY. LOWS WILL BE MID TO UPPER 50S FRIDAY
MORNING...AROUND 60 SATURDAY...THEN SHARPLY COOLER SUNDAY AND
MONDAY WITH MID 40S NORTH AND LOW 50S ELSEWHERE.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: IFR CONDITIONS ARE EXPECT TO DEVELOP...MOSTLY AFTER
MIDNIGHT WITH THE EXCEPTIONS OF BHB AND FVE. THUNDERSTORMS ARE
POSSIBLE TONIGHT. IFR WILL CONTINUE INTO TUESDAY MORNING FOR ALL
TERMINALS. VFR RETURNS DURING THE AFTERNOON FOR ALL SITES.
SHORT TERM: VFR CONDITIONS ARE EXPECTED TUESDAY THROUGH WEDNESDAY
ACROSS THE AREA.
&&
.MARINE...
NEAR TERM: FOG IS EXPECTED TO DEVELOP TONIGHT AHEAD OF A COLD
FRONT. ISOLATED THUNDERSTORMS ARE POSSIBLE. SEAS WILL PICK UP
TOWARDS 3 TO 5 FEET IN A SE SWELL TONIGHT AND CONTINUE INTO TOMORROW.
NO SCA IS EXPECTED. MODELS SEEM TO BE ABOUT 1 FOOT HIGH ON
GUIDANCE FOR THIS FRONT.
SHORT TERM: WINDS AND SEAS ARE EXPECTED TO BE BELOW SCA TUESDAY
THROUGH WEDNESDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT/MCW
SHORT TERM...BLOOMER
LONG TERM...PJR
AVIATION...HEWITT/MCW
MARINE...HEWITT/MCW/BLOOMER
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
247 PM EDT MON AUG 27 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE INTO THE AREA TONIGHT AND TUESDAY MORNING
BEFORE PUSHING SOUTH OF THE REGION TUESDAY AFTERNOON. HIGH
PRESSURE WILL PROVIDE DRY CONDITIONS FOR THE SECOND HALF OF THE
WEEK. THE REMNANTS OF ISAAC MAY IMPACT OUR AREA DURING THE
WEEKEND.
&&
.NEAR TERM /TONIGHT AND TUESDAY/...
WK CD FNT CURRENTLY OVR OH WL CROSS THE CWA LATE TNGT/ERLY TUE.
ATTM RW CVRG W/ THIS IS NOT THAT IMPRESSIVE. HRRR SHOWS SCT RW
APRCHG THE NWRN CORNER OF THE FCST AREA LATE THIS EVE. THE SREF IS
ALSO QUITE STINGY W/ RAFL IN THE MID ATLC DUR THE OVRNGT HRS. LOW
CHC POPS/LOW QPF FOR THE OVRNG HRS.
AS THE FNT WL NOT MAKE IT THRU UNTIL LATE THE TEMPS WL RMN WARM.
LOW TEMPS IN THE MU60S W OF I-95...LM70S IN THE CITES AND E OF THE
HWY.
THE FNT IS XPCTD TO MOVE THRU THE CWA DURING THE MRNG HRS. ONLY
SCATTERED SHOWER ACTIVITY WILL MAKE IT PAST THE MTNS...MUCH OF IT
DISSIPATING OVER THE APLCNS. BY MID AFTN...THE FRONT AND ANY
LINGERING PRECIP WILL BE SLIDING DOWN INTO CNTRL/SRN VA AND SOUTH
OF THE CWA. A FEW ISLTD TSTMS WILL BE POSSIBLE TOWARD EARLY AFTN
NEAR THE FRONT...AS TEMPS CLIMB INTO THE 80S - ENOUGH FOR SOME
WEAK INSTABILITY.
A STEADY NWLY BREEZE WILL PICK UP ACROSS NERN MD AND DOWN INTO THE
METRO DC AREA TOWARD THE MID-LATE AFTN...DRYING THE AREA OUT AND
LIMITING THE MAX TEMPS - THOUGH A FEW L90S ARE EXPECTED ALONG-EAST
OF I-95.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
THE COLD FRONT WILL CONTINUE TO PROGRESS SOUTH OF THE CWA TUE
NGT. ALOFT...THE BASE OF AN UPPER TROUGH WILL BE LOCATED OVER THE
MID-ATLANTIC REGION. NW FLOW ALOFT/NLY FLOW AT THE SFC WILL ADVECT
DRIER/COOLER AIR INTO THE REGION. PRESSURE SURGE FROM HIPRES
BUILDING IN FROM THE NORTH WILL LIKELY PRODUCE A 5-10 MPH WIND
OVNGT AND LIMIT RADIATIONAL COOLING. STILL EXPECT MIN TEMPS NEAR
CLIMO.
SFC HIPRES CONTINUES TO BUILD SEWD FROM THE GREAT LAKES REGION WED
AND WED NGT WHILE LARGE-SCALE TROUGHING ALOFT PERSISTS OVER ERN
CANADA AND THE NORTHEAST CONUS. MAINLY CLEAR SKIES AND SEASONABLE
TEMPERATURES WILL PERSIST DURING THIS TIME.
&&
.LONG TERM /THURSDAYTHROUGH MONDAY/...
UPPER SHORTWAVE RIDGE OVER THE CENTRAL CONUS WILL SHIFT EWD LATE
THIS WEEK AS THE REMNANTS OF ISSAC MEANDER OVER THE SRN MS RVR VLY.
BOTH GFS AND ECMWF INDICATE SOME DEGREE OF A REX BLOCK DEVELOPING
TEMPORARILY BETWEEN THESE TWO SYSTEMS THU...BEFORE IT BREAKS DOWN
FRI AND SAT AS THE RIDGE BUILDS EWD TOWARD THE ERN SEABOARD.
DURING THIS TIME...THE REMNANTS OF ISSAC WILL ROTATE AROUND THE
WRN PERIPHERY OF THE RIDGE. THERE IS UNCERTAINTY REGARDING WHEN
AND HOW MUCH MOISTURE FROM ISSAC REACH THE MID-ATLANTIC REGION.
LATEST EXTENDED-RANGE GUIDANCE INDICATES THE RIDGE BREAKING DOWN
THIS WEEKEND...WITH MOISTURE REACHING THE REGION LATE IN THE WEEKEND
AND ERY NEXT WEEK.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
A MUCH DIFFERENT AFTN THAN THE PREV TWO DAYS...W/ MOSTLY CLR SKIES
AND ONLY A FEW SCATTERED CUMULUS FIELDS - WHICH WILL DISSIPATE
TOWARD SUNSET. A COLD FRONT IS ON THE WAY HOWEVER...AND WILL MOVE
ACROSS THE REGION AFTER SUNRISE TUE. LOW-END VFR CIGS AND A STEADY
10KT BREEZE WILL ACCOMPANY THE BOUNDARY. BEHIND THE FRONT...WINDS
WILL SHIFT TOWARD WNW FOR THE AFTN HRS AND ONLY A FEW ISOLATED
SHOWERS POSSIBLE DURING THE LATE MRNG HRS.
SFC HIPRES WILL DOMINATE THE MID-ATLANTIC WX PATTERN TUE NGT THRU
THE END OF THE WEEK. VFR CONDITIONS EXPECTED DURING THIS TIME.
&&
.MARINE...
S-SELY WINDS HAVE SLACKENED INTO THE 5-10KT WIDESPREAD...THOUGH A
FEW 10-15KT GUSTS WILL PERSIST INTO THE EVE HRS. SLY CHANNELING
WILL DEVELOPING LATER TONIGHT...BRINGING LOW-END SCA WINDS TO THE
MIDDLE-LOWER MD BAY - ENDING TOWARD THE PREDAWN HRS TUE. A COLD
FRONT WILL SLIDE ACROSS THE WATERS DURING THE LATE MRNG
HRS...SWITCHING THE WIND DIRECTIONS BACK TOWARD THE W-NW FOR THE
AFTN HRS.
THE PRESSURE GRADIENT BETWEEN HIPRES BUILDING IN FROM THE GREAT
LAKES AND LOPRES ALONG A SLOW MOVING COLD FRONT THAT IS PUSHING
SOUTH OF THE WATERS WILL PRODUCE 10-15 KT NLY WINDS TUE NGT. CANNOT
RULE OUT SLIGHTLY HIGHER GUSTS IN AREAS OF THAT ARE PRONE TO NLY
CHANNELING...BUT CONFIDENCE NOT HIGH ENOUGH TO ISSUE A SCA.
LGT WINDS UNDER THE INFLUENCE OF HIPRES THRU THE SECOND HALF OF THE
WEEK.
&&
.TIDES/COASTAL FLOODING...
CANCELLED CF ADZY UNTIL 10 PM...THEN BACK IN EFFECT FOR THE WRN
SHORE OF THE MD BAY AND DC-ALEX/.
GOING INTO THE AFTN HIGH TIDE - WHICH IS THE LOWER OF THE NEXT
TWO...MANY AREAS ARE FALLING SHORT OF MINOR FLOODING THRESHOLDS.
LATER TONIGHT HOWEVER...SLY WINDS WILL STRENGTHEN MORE INTO THE
15-20 MPH RANGE AND HELP TO INCREASE POSITIVE TIDAL ANOMALIES
HEADING INTO THE NEXT H.T. CYCLE. A BETTER CHANCE EXISTS FOR THE
AREAS CURRENTLY IN THE ADZY TO REACH MINOR CF LEVELS.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 8 AM EDT
TUESDAY FOR DCZ001.
MD...COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 8 AM EDT
TUESDAY FOR MDZ007-011-014-017-018.
VA...COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 8 AM EDT
TUESDAY FOR VAZ054.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 AM EDT
TUESDAY FOR ANZ532>534-537-540>543.
&&
$$
WOODY!/GMS/KLEIN
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
156 PM EDT MON AUG 27 2012
.UPDATE...
ISSUED AT 155 PM EDT MON AUG 27 2012
SCATTERED TO BROKEN CU FIELD ACROSS THE UPPER PENINSULA EARLY THIS
AFTERNOON...PRETTY MUCH AS EXPECTED. THICKER AREA OF CU/SC TO THE
NORTHWEST OF LAKE SUPERIOR MAY BE AN ISSUE LATER TONIGHT. CURRENT
FORECAST STILL LOOKS TO BE IN GOOD SHAPE.
UPDATE ISSUED AT 1049 AM EDT MON AUG 27 2012
12Z SURFACE ANALYSIS SHOWS THE UPPER PENINSULA IN THE WAKE OF A COLD
FRONT THAT MOVED ACROSS THE REGION DURING THE OVERNIGHT HOURS...AND
WAS NOW LOCATED FROM NORTHEAST ONTARIO WEST-SOUTHWEST ACROSS THE TIP
OF THE LOWER PENINSULA AND INTO CENTRAL WISCONSIN...WEAKLY CYCLONIC
PRESSURE PATTERN ACROSS THE REGION THIS MORNING. FRONT WAS
SUPPORTED ALOFT BY AN ELONGATED PV ANOMALY...WITH WATER VAPOR
IMAGERY SHOWING A BETTER DEFINED DISTURBANCE HEADING EAST-SOUTHEAST
OVER NORTHWEST ONTARIO. CLOUDS AND SOME SHOWERS ONGOING NORTH AND
NORTHWEST OF LAKE SUPERIOR WITH THIS FEATURE. SKIES ACROSS
WESTERN/CENTRAL UPPER ARE MAINLY CLEAR TO START WITH JUST A PATCH OF
AC EAST OF THE KEWEENAW.
NORTHWEST ONTARIO SHORT WAVE TROUGH FORECAST TO SLIDE INTO WESTERN
UPPER LATER THIS AFTERNOON...BUT THE ENVIRONMENT AHEAD OF THIS
FEATURE IS NOT PARTICULARLY MOIST...AS MUCH OF THE MID/UPPER LEVEL
MOISTURE IS TO THE NORTH OF THE MAIN VORTICITY CENTER. SO OUTSIDE
OF A LITTLE DIURNALLY DRIVEN CU DEVELOPMENT...SHOULD BE A NICE
AFTERNOON. 12Z GRB SOUNDING HAD A NICE MIXED RESIDUAL LAYER BETWEEN
950-780MB...MIXING TO THIS POINT YIELDS AN AFTERNOON HIGH OF 79F
WHICH CURRENT FORECAST SEEMS TO HAVE WELL IN HAND. SO NO BIG
CHANGES IN THE FORECAST AT THIS POINT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 505 AM EDT MON AUG 27 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH OVER
HUDSON BAY AND A RIDGE FROM THE SRN ROCKIES INTO THE CNTRL PLAINS
RESULTING IN WNW FLOW FROM THE CANADIAN PRAIRIES INTO THE NRN GREAT
LAKES. AT THE SFC...A COLD FRONT THROUGH CNTRL UPPER MI CONTINUED TO
SLIDE TO THE EAST AS HIGH PRES FROM SASK INTO THE NRN PLAINS BUILDS
TOWARD THE AREA. LOW CLOUDS AND FOG AHEAD OF THE FRONT OVER THE ERN
CWA WERE DISSIPATING AS WEAK DRY AIR ADVECTION SCOURS OUT THE LOW
LEVEL MOISTURE. HOWEVER...SOME PATCHY SHALLOW FOG REMAINED OVER
INLAND PORTIONS OF CNTRL UPPER MI. AN ALTHOUGH SKIES WERE MOSTLY
CLEAR OVER MN...NRN WI AND W UPPER MI...AN EXTENSIVE AREA OF
LOW/MID CLOUDS WAS SPREADING THROUGH NW ONTARIO IN THE COOLER AIR WHERE
850 MB TEMPS WERE BLO 8C.
TODAY...AFTER THE LOW CLOUDS MOVE OUT OF THE EAST...EXPECT MOSTLY
SUNNY SKIES ACROSS THE AREA. MIXING SHOULD BOOST TEMPS INTO THE
UPPER 70S TO AROUND 80...GIVEN UPSTREAM MAX READINGS SUNDAY IN
AIRMASS WITH 850 MB TEMPS AROUND 12C. MIXING SHOULD ALSO DROP
DEWPOINTS TO AROUND 50 INLAND.
TONIGHT...AS THE MOISTURE AND COOLER AIR SAGS INTO THE AREA LATE
TONIGHT...SOME INCREASE IN CLOUDS MAY BE POSSIBLE OVER THE NORTH AND
EAST PORTIONS OF THE CWA...PER NAM 925-750 MB RH FCST. HOWEVER...ANY
CLOUDS SHOULD BE TRANSIENT MOVING OUT AROUND DAYBREAK AND HAVE
ONLY LIMITED IMPACT ON MIN TEMPS WHICH SHOULD DROP TO AROUND 50
INLAND.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 505 AM EDT MON AUG 27 2012
MAIN FOCUS IN THE EXTENDED IS WARM...MAINLY DRY CONDITIONS. A COUPLE
OF MODELS ARE SHOWING SOME PRECIP THU IN THE WAA AHEAD OF A
TROUGH...AND AGAIN WITH AN UPPER/SFC TROUGH AND COLD FRONT ON
SUNDAY. HOWEVER...WITH EXPECTED LACK OF MOISTURE...AM NOT TOO
EXCITED ABOUT PRECIP CHANCES.
ON TUESDAY...THE CWA WILL BE UNDER NW FLOW ALOFT BETWEEN AN
AMPLIFIED 500MB RIDGE AXIS FROM CO THROUGH SASK INTO THE NW
TERRITORIES AND A 500MB TROUGH FROM NRN QUEBEC DOWN TO ISAAC IN THE
GULF OF MEXICO. A SFC RIDGE WILL BE OVER THE CWA TUESDAY WITH 850MB
TEMPS AT 18Z TUE FROM 8C E TO 12C W. THIS SHOULD LEAD TO SUNNY SKIES
WITH HIGHS IN THE 70S.
SW LOW LEVEL FLOW INCREASES THROUGH THE DAY WED AS THE UPPER RIDGE
AXIS MOVES TO JUST W OF THE CWA BY 00Z THU. A SHORTWAVE TROUGH WILL
MOVE INTO WRN CANADA/NW CONUS WED...RESULTING IN A SFC LOW OVER SRN
SASK AND A TROUGH LEEWARD OF THE ROCKIES. WITH WAA AHEAD OF THIS
SYSTEM...850MB TEMPS INCREASE TO AROUND 18C BY 00Z THU AS THE EML
ADVECTS INTO THE AREA. HIGHS WED SHOULD BE IN THE MID 80S TO AROUND
90...EXCEPT IN THE 70S DOWNWIND OF LAKE MICHIGAN. LOW LEVEL MOISTURE
VARIES BETWEEN MODELS...WITH THE 00Z/27 GFS BEING ON THE HIGH SIDE
/1000-700MB RH STILL UNDER 60 PERCENT FOR THE MOST PART/ AND THE
00Z/27 NAM ON THE LOW SIDE /LESS THAN 40 PERCENT 1000-700MB RH/.
WILL GO WITH A MORE MODERATED SOLUTION OF THE ECMWF WHICH WILL LEAD
TO LOW MIN SFC RH. SFC WINDS SHOULD BE FROM THE SSW AT 10-15KTS WITH
GUSTS TO AROUND 20KTS.
THU WILL BE THE HOTTEST DAY OF THE WEEK BENEATH THE HEIGHT OF THE
EML MOVING OVERHEAD AND THE 500MB RIDGE AXIS MOVING THROUGH. THE
12Z/26 ECMWF HAS 850MB TEMPS OF AROUND 22C...BUT THE GFS IS WARMER
AT AROUND 26C. EVEN IF THE COOLER ECMWF VERIFIES...HIGH TEMPS IN THE
80S TO LOW 90S SHOULD BE ABLE TO BE REALIZED /COOLEST DOWNWIND OF
LAKE MICHIGAN. SW LOW LEVEL FLOW WILL BE STRONGER AS THE SFC LOW
MOVES FROM CENTRAL MANITOBA TO FAR NW ONTARIO...BRINGING A COLD
FRONT TO THE FAR WRN CWA LATE THU EVENING. SW SFC WINDS WILL BE
AROUND 15KTS WITH GUSTS UP TO 20-25KTS. VERY DRY MID/LOW LEVELS WILL
AGAIN LEAD TO LOW MIN SFC RH...SO FIRE WEATHER CONCERNS WILL BE MORE
ELEVATED.
AFTER THE PASSAGE OF THE SHORTWAVE THU AND COLD FRONT THU
NIGHT...SFC HIGH PRESSURE AND UPPER RIDGING BECOME MORE DOMINANT
OVER THE CWA THROUGH SAT. HIGH TEMPS FRI COULD STILL BE PRETTY WARM
AS MODELS SHOW 850MB TEMPS OF 15-20C BUT WITH MORE WNW LOW LEVEL
WINDS. AT SHOULD BE A BIT COOLER IN SOME SPOTS AS 850MB TEMPS LOOK
MORE UNIFORM AT AROUND 14C WITH LIGHT LOW LEVEL FLOW. MODELS THEN
SHOW A STRONGER SHORTWAVE MOVING INTO WRN ONTARIO LATE SUNDAY...WITH
A SFC LOW MOVING OVER OR JUST N OF THE CWA SUN. THIS ALSO BRING A
SFC COLD FRONT INTO THE CWA SUN AFTERNOON/EVENING...WHICH WOULD
PROVIDE A BETTER CHANCE OF RAIN AS LOW LEVEL MOISTURE DOES IMPROVE
SOME. STILL NOT TOO CONFIDENT IN PRECIP CHANCES ON SUN GIVEN THAT
MODELS HAVE BEEN VARYING SOME WITH THIS SYSTEM AND THAT MODELS BRING
REMNANTS OF ISAAC WELL TO OUR S...WHICH MAY ACT TO KEEP THE BETTER
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 155 PM EDT MON AUG 27 2012
MAINLY VFR CONDITIONS EXPECTED THIS AFTERNOON THROUGH TONIGHT...
THOUGH REMNANTS OF SC FIELD ACROSS NORTHWEST ONTARIO AND THE
MINNESOTA ARROWHEAD MAY IMPACT CMX/MQT THROUGH TONIGHT. WINDS
EXPECTED TO BECOME LIGHT TONIGHT AS HIGH PRESSURE BUILDS IN FROM THE
WEST.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 505 AM EDT MON AUG 27 2012
WINDS SHOULD REMAIN LESS THAN 30KTS THROUGH THE FCST PERIOD. HIGH
PRES OVER S CENTRAL CANADA WILL SLOWLY BUILD OVER THE UPPER GREAT
LAKES THROUGH TUESDAY...BEFORE DIPPING ACROSS THE LOWER GREAT LAKES
TUESDAY NIGHT INTO WEDNESDAY. LOW PRESSURE OVER SOUTHERN AND CENTRAL
CANADA THURSDAY MORNING WILL SWING ACROSS ONTARIO AND HUDSON BAY
THURSDAY NIGHT...WITH A TROUGH PUSHING ACROSS LAKE SUPERIOR THURSDAY
AFTERNOON INTO FRIDAY. A RIDGE OF HIGH PRESSURE WILL THEN SLIP
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LS...NONE.
LM...NONE.
&&
$$
UPDATE...JPB
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JPB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1048 AM EDT MON AUG 27 2012
.UPDATE...
ISSUED AT 1049 AM EDT MON AUG 27 2012
12Z SURFACE ANALYSIS SHOWS THE UPPER PENINSULA IN THE WAKE OF A COLD
FRONT THAT MOVED ACROSS THE REGION DURING THE OVERNIGHT HOURS...AND
WAS NOW LOCATED FROM NORTHEAST ONTARIO WEST-SOUTHWEST ACROSS THE TIP
OF THE LOWER PENINSULA AND INTO CENTRAL WISCONSIN...WEAKLY CYCLONIC
PRESSURE PATTERN ACROSS THE REGION THIS MORNING. FRONT WAS
SUPPORTED ALOFT BY AN ELONGATED PV ANOMALY...WITH WATER VAPOR
IMAGERY SHOWING A BETTER DEFINED DISTURBANCE HEADING EAST-SOUTHEAST
OVER NORTHWEST ONTARIO. CLOUDS AND SOME SHOWERS ONGOING NORTH AND
NORTHWEST OF LAKE SUPERIOR WITH THIS FEATURE. SKIES ACROSS
WESTERN/CENTRAL UPPER ARE MAINLY CLEAR TO START WITH JUST A PATCH OF
AC EAST OF THE KEWEENAW.
NORTHWEST ONTARIO SHORT WAVE TROUGH FORECAST TO SLIDE INTO WESTERN
UPPER LATER THIS AFTERNOON...BUT THE ENVIRONMENT AHEAD OF THIS
FEATURE IS NOT PARTICULARLY MOIST...AS MUCH OF THE MID/UPPER LEVEL
MOISTURE IS TO THE NORTH OF THE MAIN VORTICITY CENTER. SO OUTSIDE
OF A LITTLE DIURNALLY DRIVEN CU DEVELOPMENT...SHOULD BE A NICE
AFTERNOON. 12Z GRB SOUNDING HAD A NICE MIXED RESIDUAL LAYER BETWEEN
950-780MB...MIXING TO THIS POINT YIELDS AN AFTERNOON HIGH OF 79F
WHICH CURRENT FORECAST SEEMS TO HAVE WELL IN HAND. SO NO BIG
CHANGES IN THE FORECAST AT THIS POINT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 505 AM EDT MON AUG 27 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH OVER
HUDSON BAY AND A RIDGE FROM THE SRN ROCKIES INTO THE CNTRL PLAINS
RESULTING IN WNW FLOW FROM THE CANADIAN PRAIRIES INTO THE NRN GREAT
LAKES. AT THE SFC...A COLD FRONT THROUGH CNTRL UPPER MI CONTINUED TO
SLIDE TO THE EAST AS HIGH PRES FROM SASK INTO THE NRN PLAINS BUILDS
TOWARD THE AREA. LOW CLOUDS AND FOG AHEAD OF THE FRONT OVER THE ERN
CWA WERE DISSIPATING AS WEAK DRY AIR ADVECTION SCOURS OUT THE LOW
LEVEL MOISTURE. HOWEVER...SOME PATCHY SHALLOW FOG REMAINED OVER
INLAND PORTIONS OF CNTRL UPPER MI. AN ALTHOUGH SKIES WERE MOSTLY
CLEAR OVER MN...NRN WI AND W UPPER MI...AN EXTENSIVE AREA OF
LOW/MID CLOUDS WAS SPREADING THROUGH NW ONTARIO IN THE COOLER AIR WHERE
850 MB TEMPS WERE BLO 8C.
TODAY...AFTER THE LOW CLOUDS MOVE OUT OF THE EAST...EXPECT MOSTLY
SUNNY SKIES ACROSS THE AREA. MIXING SHOULD BOOST TEMPS INTO THE
UPPER 70S TO AROUND 80...GIVEN UPSTREAM MAX READINGS SUNDAY IN
AIRMASS WITH 850 MB TEMPS AROUND 12C. MIXING SHOULD ALSO DROP
DEWPOINTS TO AROUND 50 INLAND.
TONIGHT...AS THE MOISTURE AND COOLER AIR SAGS INTO THE AREA LATE
TONIGHT...SOME INCREASE IN CLOUDS MAY BE POSSIBLE OVER THE NORTH AND
EAST PORTIONS OF THE CWA...PER NAM 925-750 MB RH FCST. HOWEVER...ANY
CLOUDS SHOULD BE TRANSIENT MOVING OUT AROUND DAYBREAK AND HAVE
ONLY LIMITED IMPACT ON MIN TEMPS WHICH SHOULD DROP TO AROUND 50
INLAND.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 505 AM EDT MON AUG 27 2012
MAIN FOCUS IN THE EXTENDED IS WARM...MAINLY DRY CONDITIONS. A COUPLE
OF MODELS ARE SHOWING SOME PRECIP THU IN THE WAA AHEAD OF A
TROUGH...AND AGAIN WITH AN UPPER/SFC TROUGH AND COLD FRONT ON
SUNDAY. HOWEVER...WITH EXPECTED LACK OF MOISTURE...AM NOT TOO
EXCITED ABOUT PRECIP CHANCES.
ON TUESDAY...THE CWA WILL BE UNDER NW FLOW ALOFT BETWEEN AN
AMPLIFIED 500MB RIDGE AXIS FROM CO THROUGH SASK INTO THE NW
TERRITORIES AND A 500MB TROUGH FROM NRN QUEBEC DOWN TO ISAAC IN THE
GULF OF MEXICO. A SFC RIDGE WILL BE OVER THE CWA TUESDAY WITH 850MB
TEMPS AT 18Z TUE FROM 8C E TO 12C W. THIS SHOULD LEAD TO SUNNY SKIES
WITH HIGHS IN THE 70S.
SW LOW LEVEL FLOW INCREASES THROUGH THE DAY WED AS THE UPPER RIDGE
AXIS MOVES TO JUST W OF THE CWA BY 00Z THU. A SHORTWAVE TROUGH WILL
MOVE INTO WRN CANADA/NW CONUS WED...RESULTING IN A SFC LOW OVER SRN
SASK AND A TROUGH LEEWARD OF THE ROCKIES. WITH WAA AHEAD OF THIS
SYSTEM...850MB TEMPS INCREASE TO AROUND 18C BY 00Z THU AS THE EML
ADVECTS INTO THE AREA. HIGHS WED SHOULD BE IN THE MID 80S TO AROUND
90...EXCEPT IN THE 70S DOWNWIND OF LAKE MICHIGAN. LOW LEVEL MOISTURE
VARIES BETWEEN MODELS...WITH THE 00Z/27 GFS BEING ON THE HIGH SIDE
/1000-700MB RH STILL UNDER 60 PERCENT FOR THE MOST PART/ AND THE
00Z/27 NAM ON THE LOW SIDE /LESS THAN 40 PERCENT 1000-700MB RH/.
WILL GO WITH A MORE MODERATED SOLUTION OF THE ECMWF WHICH WILL LEAD
TO LOW MIN SFC RH. SFC WINDS SHOULD BE FROM THE SSW AT 10-15KTS WITH
GUSTS TO AROUND 20KTS.
THU WILL BE THE HOTTEST DAY OF THE WEEK BENEATH THE HEIGHT OF THE
EML MOVING OVERHEAD AND THE 500MB RIDGE AXIS MOVING THROUGH. THE
12Z/26 ECMWF HAS 850MB TEMPS OF AROUND 22C...BUT THE GFS IS WARMER
AT AROUND 26C. EVEN IF THE COOLER ECMWF VERIFIES...HIGH TEMPS IN THE
80S TO LOW 90S SHOULD BE ABLE TO BE REALIZED /COOLEST DOWNWIND OF
LAKE MICHIGAN. SW LOW LEVEL FLOW WILL BE STRONGER AS THE SFC LOW
MOVES FROM CENTRAL MANITOBA TO FAR NW ONTARIO...BRINGING A COLD
FRONT TO THE FAR WRN CWA LATE THU EVENING. SW SFC WINDS WILL BE
AROUND 15KTS WITH GUSTS UP TO 20-25KTS. VERY DRY MID/LOW LEVELS WILL
AGAIN LEAD TO LOW MIN SFC RH...SO FIRE WEATHER CONCERNS WILL BE MORE
ELEVATED.
AFTER THE PASSAGE OF THE SHORTWAVE THU AND COLD FRONT THU
NIGHT...SFC HIGH PRESSURE AND UPPER RIDGING BECOME MORE DOMINANT
OVER THE CWA THROUGH SAT. HIGH TEMPS FRI COULD STILL BE PRETTY WARM
AS MODELS SHOW 850MB TEMPS OF 15-20C BUT WITH MORE WNW LOW LEVEL
WINDS. AT SHOULD BE A BIT COOLER IN SOME SPOTS AS 850MB TEMPS LOOK
MORE UNIFORM AT AROUND 14C WITH LIGHT LOW LEVEL FLOW. MODELS THEN
SHOW A STRONGER SHORTWAVE MOVING INTO WRN ONTARIO LATE SUNDAY...WITH
A SFC LOW MOVING OVER OR JUST N OF THE CWA SUN. THIS ALSO BRING A
SFC COLD FRONT INTO THE CWA SUN AFTERNOON/EVENING...WHICH WOULD
PROVIDE A BETTER CHANCE OF RAIN AS LOW LEVEL MOISTURE DOES IMPROVE
SOME. STILL NOT TOO CONFIDENT IN PRECIP CHANCES ON SUN GIVEN THAT
MODELS HAVE BEEN VARYING SOME WITH THIS SYSTEM AND THAT MODELS BRING
REMNANTS OF ISAAC WELL TO OUR S...WHICH MAY ACT TO KEEP THE BETTER
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 738 AM EDT MON AUG 27 2012
WITH HIGH PRESSURE AND DRY AIR BUILDING OVER THE REGION...VFR
CONDITIONS ARE EXPECTED THROUGH THE FCST PERIOD. A PERIOD OF BKN
CLOUDS TONIGHT AT CMX/SAW ASSOCIATED WITH COLDER AIR SLIDING IN
FROM NORTH IS EXPECTED TO REMAIN ABOVE 3K FT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 505 AM EDT MON AUG 27 2012
WINDS SHOULD REMAIN LESS THAN 30KTS THROUGH THE FCST PERIOD. HIGH
PRES OVER S CENTRAL CANADA WILL SLOWLY BUILD OVER THE UPPER GREAT
LAKES THROUGH TUESDAY...BEFORE DIPPING ACROSS THE LOWER GREAT LAKES
TUESDAY NIGHT INTO WEDNESDAY. LOW PRESSURE OVER SOUTHERN AND CENTRAL
CANADA THURSDAY MORNING WILL SWING ACROSS ONTARIO AND HUDSON BAY
THURSDAY NIGHT...WITH A TROUGH PUSHING ACROSS LAKE SUPERIOR THURSDAY
AFTERNOON INTO FRIDAY. A RIDGE OF HIGH PRESSURE WILL THEN SLIP
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LS...NONE.
LM...NONE.
&&
$$
UPDATE...JPB
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
739 AM EDT MON AUG 27 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 505 AM EDT MON AUG 27 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH OVER
HUDSON BAY AND A RIDGE FROM THE SRN ROCKIES INTO THE CNTRL PLAINS
RESULTING IN WNW FLOW FROM THE CANADIAN PRAIRIES INTO THE NRN GREAT
LAKES. AT THE SFC...A COLD FRONT THROUGH CNTRL UPPER MI CONTINUED TO
SLIDE TO THE EAST AS HIGH PRES FROM SASK INTO THE NRN PLAINS BUILDS
TOWARD THE AREA. LOW CLOUDS AND FOG AHEAD OF THE FRONT OVER THE ERN
CWA WERE DISSIPATING AS WEAK DRY AIR ADVECTION SCOURS OUT THE LOW
LEVEL MOISTURE. HOWEVER...SOME PATCHY SHALLOW FOG REMAINED OVER
INLAND PORTIONS OF CNTRL UPPER MI. AN ALTHOUGH SKIES WERE MOSTLY
CLEAR OVER MN...NRN WI AND W UPPER MI...AN EXTENSIVE AREA OF
LOW/MID CLOUDS WAS SPREADING THROUGH NW ONTARIO IN THE COOLER AIR WHERE
850 MB TEMPS WERE BLO 8C.
TODAY...AFTER THE LOW CLOUDS MOVE OUT OF THE EAST...EXPECT MOSTLY
SUNNY SKIES ACROSS THE AREA. MIXING SHOULD BOOST TEMPS INTO THE
UPPER 70S TO AROUND 80...GIVEN UPSTREAM MAX READINGS SUNDAY IN
AIRMASS WITH 850 MB TEMPS AROUND 12C. MIXING SHOULD ALSO DROP
DEWPOINTS TO AROUND 50 INLAND.
TONIGHT...AS THE MOISTURE AND COOLER AIR SAGS INTO THE AREA LATE
TONIGHT...SOME INCREASE IN CLOUDS MAY BE POSSIBLE OVER THE NORTH AND
EAST PORTIONS OF THE CWA...PER NAM 925-750 MB RH FCST. HOWEVER...ANY
CLOUDS SHOULD BE TRANSIENT MOVING OUT AROUND DAYBREAK AND HAVE
ONLY LIMITED IMPACT ON MIN TEMPS WHICH SHOULD DROP TO AROUND 50
INLAND.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 505 AM EDT MON AUG 27 2012
MAIN FOCUS IN THE EXTENDED IS WARM...MAINLY DRY CONDITIONS. A COUPLE
OF MODELS ARE SHOWING SOME PRECIP THU IN THE WAA AHEAD OF A
TROUGH...AND AGAIN WITH AN UPPER/SFC TROUGH AND COLD FRONT ON
SUNDAY. HOWEVER...WITH EXPECTED LACK OF MOISTURE...AM NOT TOO
EXCITED ABOUT PRECIP CHANCES.
ON TUESDAY...THE CWA WILL BE UNDER NW FLOW ALOFT BETWEEN AN
AMPLIFIED 500MB RIDGE AXIS FROM CO THROUGH SASK INTO THE NW
TERRITORIES AND A 500MB TROUGH FROM NRN QUEBEC DOWN TO ISAAC IN THE
GULF OF MEXICO. A SFC RIDGE WILL BE OVER THE CWA TUESDAY WITH 850MB
TEMPS AT 18Z TUE FROM 8C E TO 12C W. THIS SHOULD LEAD TO SUNNY SKIES
WITH HIGHS IN THE 70S.
SW LOW LEVEL FLOW INCREASES THROUGH THE DAY WED AS THE UPPER RIDGE
AXIS MOVES TO JUST W OF THE CWA BY 00Z THU. A SHORTWAVE TROUGH WILL
MOVE INTO WRN CANADA/NW CONUS WED...RESULTING IN A SFC LOW OVER SRN
SASK AND A TROUGH LEEWARD OF THE ROCKIES. WITH WAA AHEAD OF THIS
SYSTEM...850MB TEMPS INCREASE TO AROUND 18C BY 00Z THU AS THE EML
ADVECTS INTO THE AREA. HIGHS WED SHOULD BE IN THE MID 80S TO AROUND
90...EXCEPT IN THE 70S DOWNWIND OF LAKE MICHIGAN. LOW LEVEL MOISTURE
VARIES BETWEEN MODELS...WITH THE 00Z/27 GFS BEING ON THE HIGH SIDE
/1000-700MB RH STILL UNDER 60 PERCENT FOR THE MOST PART/ AND THE
00Z/27 NAM ON THE LOW SIDE /LESS THAN 40 PERCENT 1000-700MB RH/.
WILL GO WITH A MORE MODERATED SOLUTION OF THE ECMWF WHICH WILL LEAD
TO LOW MIN SFC RH. SFC WINDS SHOULD BE FROM THE SSW AT 10-15KTS WITH
GUSTS TO AROUND 20KTS.
THU WILL BE THE HOTTEST DAY OF THE WEEK BENEATH THE HEIGHT OF THE
EML MOVING OVERHEAD AND THE 500MB RIDGE AXIS MOVING THROUGH. THE
12Z/26 ECMWF HAS 850MB TEMPS OF AROUND 22C...BUT THE GFS IS WARMER
AT AROUND 26C. EVEN IF THE COOLER ECMWF VERIFIES...HIGH TEMPS IN THE
80S TO LOW 90S SHOULD BE ABLE TO BE REALIZED /COOLEST DOWNWIND OF
LAKE MICHIGAN. SW LOW LEVEL FLOW WILL BE STRONGER AS THE SFC LOW
MOVES FROM CENTRAL MANITOBA TO FAR NW ONTARIO...BRINGING A COLD
FRONT TO THE FAR WRN CWA LATE THU EVENING. SW SFC WINDS WILL BE
AROUND 15KTS WITH GUSTS UP TO 20-25KTS. VERY DRY MID/LOW LEVELS WILL
AGAIN LEAD TO LOW MIN SFC RH...SO FIRE WEATHER CONCERNS WILL BE MORE
ELEVATED.
AFTER THE PASSAGE OF THE SHORTWAVE THU AND COLD FRONT THU
NIGHT...SFC HIGH PRESSURE AND UPPER RIDGING BECOME MORE DOMINANT
OVER THE CWA THROUGH SAT. HIGH TEMPS FRI COULD STILL BE PRETTY WARM
AS MODELS SHOW 850MB TEMPS OF 15-20C BUT WITH MORE WNW LOW LEVEL
WINDS. AT SHOULD BE A BIT COOLER IN SOME SPOTS AS 850MB TEMPS LOOK
MORE UNIFORM AT AROUND 14C WITH LIGHT LOW LEVEL FLOW. MODELS THEN
SHOW A STRONGER SHORTWAVE MOVING INTO WRN ONTARIO LATE SUNDAY...WITH
A SFC LOW MOVING OVER OR JUST N OF THE CWA SUN. THIS ALSO BRING A
SFC COLD FRONT INTO THE CWA SUN AFTERNOON/EVENING...WHICH WOULD
PROVIDE A BETTER CHANCE OF RAIN AS LOW LEVEL MOISTURE DOES IMPROVE
SOME. STILL NOT TOO CONFIDENT IN PRECIP CHANCES ON SUN GIVEN THAT
MODELS HAVE BEEN VARYING SOME WITH THIS SYSTEM AND THAT MODELS BRING
REMNANTS OF ISAAC WELL TO OUR S...WHICH MAY ACT TO KEEP THE BETTER
MOISTURE FOCUSED FARTHER S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 738 AM EDT MON AUG 27 2012
WITH HIGH PRESSURE AND DRY AIR BUILDING OVER THE REGION...VFR
CONDITIONS ARE EXPECTED THROUGH THE FCST PERIOD. A PERIOD OF BKN
CLOUDS TONIGHT AT CMX/SAW ASSOCIATED WITH COLDER AIR SLIDING IN
FROM NORTH IS EXPECTED TO REMAIN ABOVE 3K FT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 505 AM EDT MON AUG 27 2012
WINDS SHOULD REMAIN LESS THAN 30KTS THROUGH THE FCST PERIOD. HIGH
PRES OVER S CENTRAL CANADA WILL SLOWLY BUILD OVER THE UPPER GREAT
LAKES THROUGH TUESDAY...BEFORE DIPPING ACROSS THE LOWER GREAT LAKES
TUESDAY NIGHT INTO WEDNESDAY. LOW PRESSURE OVER SOUTHERN AND CENTRAL
CANADA THURSDAY MORNING WILL SWING ACROSS ONTARIO AND HUDSON BAY
THURSDAY NIGHT...WITH A TROUGH PUSHING ACROSS LAKE SUPERIOR THURSDAY
AFTERNOON INTO FRIDAY. A RIDGE OF HIGH PRESSURE WILL THEN SLIP
ACROSS LAKE SUPERIOR LATE FRIDAY BEHIND THE TROUGH.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
506 AM EDT MON AUG 27 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 505 AM EDT MON AUG 27 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH OVER
HUDSON BAY AND A RIDGE FROM THE SRN ROCKIES INTO THE CNTRL PLAINS
RESULTING IN WNW FLOW FROM THE CANADIAN PRAIRIES INTO THE NRN GREAT
LAKES. AT THE SFC...A COLD FRONT THROUGH CNTRL UPPER MI CONTINUED TO
SLIDE TO THE EAST AS HIGH PRES FROM SASK INTO THE NRN PLAINS BUILDS
TOWARD THE AREA. LOW CLOUDS AND FOG AHEAD OF THE FRONT OVER THE ERN
CWA WERE DISSIPATING AS WEAK DRY AIR ADVECTION SCOURS OUT THE LOW
LEVEL MOISTURE. HOWEVER...SOME PATCHY SHALLOW FOG REMAINED OVER
INLAND PORTIONS OF CNTRL UPPER MI. AN ALTHOUGH SKIES WERE MOSTLY
CLEAR OVER MN...NRN WI AND W UPPER MI...AN EXTENSIVE AREA OF
LOW/MID CLOUDS WAS SPREADING THROUGH NW ONTARIO IN THE COOLER AIR WHERE
850 MB TEMPS WERE BLO 8C.
TODAY...AFTER THE LOW CLOUDS MOVE OUT OF THE EAST...EXPECT MOSTLY
SUNNY SKIES ACROSS THE AREA. MIXING SHOULD BOOST TEMPS INTO THE
UPPER 70S TO AROUND 80...GIVEN UPSTREAM MAX READINGS SUNDAY IN
AIRMASS WITH 850 MB TEMPS AROUND 12C. MIXING SHOULD ALSO DROP
DEWPOINTS TO AROUND 50 INLAND.
TONIGHT...AS THE MOISTURE AND COOLER AIR SAGS INTO THE AREA LATE
TONIGHT...SOME INCREASE IN CLOUDS MAY BE POSSIBLE OVER THE NORTH AND
EAST PORTIONS OF THE CWA...PER NAM 925-750 MB RH FCST. HOWEVER...ANY
CLOUDS SHOULD BE TRANSIENT MOVING OUT AROUND DAYBREAK AND HAVE
ONLY LIMITED IMPACT ON MIN TEMPS WHICH SHOULD DROP TO AROUND 50
INLAND.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 505 AM EDT MON AUG 27 2012
MAIN FOCUS IN THE EXTENDED IS WARM...MAINLY DRY CONDITIONS. A COUPLE
OF MODELS ARE SHOWING SOME PRECIP THU IN THE WAA AHEAD OF A
TROUGH...AND AGAIN WITH AN UPPER/SFC TROUGH AND COLD FRONT ON
SUNDAY. HOWEVER...WITH EXPECTED LACK OF MOISTURE...AM NOT TOO
EXCITED ABOUT PRECIP CHANCES.
ON TUESDAY...THE CWA WILL BE UNDER NW FLOW ALOFT BETWEEN AN
AMPLIFIED 500MB RIDGE AXIS FROM CO THROUGH SASK INTO THE NW
TERRITORIES AND A 500MB TROUGH FROM NRN QUEBEC DOWN TO ISAAC IN THE
GULF OF MEXICO. A SFC RIDGE WILL BE OVER THE CWA TUESDAY WITH 850MB
TEMPS AT 18Z TUE FROM 8C E TO 12C W. THIS SHOULD LEAD TO SUNNY SKIES
WITH HIGHS IN THE 70S.
SW LOW LEVEL FLOW INCREASES THROUGH THE DAY WED AS THE UPPER RIDGE
AXIS MOVES TO JUST W OF THE CWA BY 00Z THU. A SHORTWAVE TROUGH WILL
MOVE INTO WRN CANADA/NW CONUS WED...RESULTING IN A SFC LOW OVER SRN
SASK AND A TROUGH LEEWARD OF THE ROCKIES. WITH WAA AHEAD OF THIS
SYSTEM...850MB TEMPS INCREASE TO AROUND 18C BY 00Z THU AS THE EML
ADVECTS INTO THE AREA. HIGHS WED SHOULD BE IN THE MID 80S TO AROUND
90...EXCEPT IN THE 70S DOWNWIND OF LAKE MICHIGAN. LOW LEVEL MOISTURE
VARIES BETWEEN MODELS...WITH THE 00Z/27 GFS BEING ON THE HIGH SIDE
/1000-700MB RH STILL UNDER 60 PERCENT FOR THE MOST PART/ AND THE
00Z/27 NAM ON THE LOW SIDE /LESS THAN 40 PERCENT 1000-700MB RH/.
WILL GO WITH A MORE MODERATED SOLUTION OF THE ECMWF WHICH WILL LEAD
TO LOW MIN SFC RH. SFC WINDS SHOULD BE FROM THE SSW AT 10-15KTS WITH
GUSTS TO AROUND 20KTS.
THU WILL BE THE HOTTEST DAY OF THE WEEK BENEATH THE HEIGHT OF THE
EML MOVING OVERHEAD AND THE 500MB RIDGE AXIS MOVING THROUGH. THE
12Z/26 ECMWF HAS 850MB TEMPS OF AROUND 22C...BUT THE GFS IS WARMER
AT AROUND 26C. EVEN IF THE COOLER ECMWF VERIFIES...HIGH TEMPS IN THE
80S TO LOW 90S SHOULD BE ABLE TO BE REALIZED /COOLEST DOWNWIND OF
LAKE MICHIGAN. SW LOW LEVEL FLOW WILL BE STRONGER AS THE SFC LOW
MOVES FROM CENTRAL MANITOBA TO FAR NW ONTARIO...BRINGING A COLD
FRONT TO THE FAR WRN CWA LATE THU EVENING. SW SFC WINDS WILL BE
AROUND 15KTS WITH GUSTS UP TO 20-25KTS. VERY DRY MID/LOW LEVELS WILL
AGAIN LEAD TO LOW MIN SFC RH...SO FIRE WEATHER CONCERNS WILL BE MORE
ELEVATED.
AFTER THE PASSAGE OF THE SHORTWAVE THU AND COLD FRONT THU
NIGHT...SFC HIGH PRESSURE AND UPPER RIDGING BECOME MORE DOMINANT
OVER THE CWA THROUGH SAT. HIGH TEMPS FRI COULD STILL BE PRETTY WARM
AS MODELS SHOW 850MB TEMPS OF 15-20C BUT WITH MORE WNW LOW LEVEL
WINDS. AT SHOULD BE A BIT COOLER IN SOME SPOTS AS 850MB TEMPS LOOK
MORE UNIFORM AT AROUND 14C WITH LIGHT LOW LEVEL FLOW. MODELS THEN
SHOW A STRONGER SHORTWAVE MOVING INTO WRN ONTARIO LATE SUNDAY...WITH
A SFC LOW MOVING OVER OR JUST N OF THE CWA SUN. THIS ALSO BRING A
SFC COLD FRONT INTO THE CWA SUN AFTERNOON/EVENING...WHICH WOULD
PROVIDE A BETTER CHANCE OF RAIN AS LOW LEVEL MOISTURE DOES IMPROVE
SOME. STILL NOT TOO CONFIDENT IN PRECIP CHANCES ON SUN GIVEN THAT
MODELS HAVE BEEN VARYING SOME WITH THIS SYSTEM AND THAT MODELS BRING
REMNANTS OF ISAAC WELL TO OUR S...WHICH MAY ACT TO KEEP THE BETTER
MOISTURE FOCUSED FARTHER S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 127 AM EDT MON AUG 27 2012
EXPECT FOG AT SAW TO GRADUALLY LIFT EARLY THIS MRNG WITH THE ARRIVAL
OF DRIER AIR ASSOCIATED WITH HI PRES BLDG E FM THE PLAINS.
OTHERWISE...THIS DRY AIR WL BRING VFR CONDITIONS THIS FCST PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 505 AM EDT MON AUG 27 2012
WINDS SHOULD REMAIN LESS THAN 30KTS THROUGH THE FCST PERIOD. HIGH
PRES OVER S CENTRAL CANADA WILL SLOWLY BUILD OVER THE UPPER GREAT
LAKES THROUGH TUESDAY...BEFORE DIPPING ACROSS THE LOWER GREAT LAKES
TUESDAY NIGHT INTO WEDNESDAY. LOW PRESSURE OVER SOUTHERN AND CENTRAL
CANADA THURSDAY MORNING WILL SWING ACROSS ONTARIO AND HUDSON BAY
THURSDAY NIGHT...WITH A TROUGH PUSHING ACROSS LAKE SUPERIOR THURSDAY
AFTERNOON INTO FRIDAY. A RIDGE OF HIGH PRESSURE WILL THEN SLIP
ACROSS LAKE SUPERIOR LATE FRIDAY BEHIND THE TROUGH.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1043 PM CDT TUE AUG 28 2012
.UPDATE...FOR 06Z AVIATION DISCUSSION BELOW
&&
.DISCUSSION.../ISSUED 413 PM CDT TUE AUG 28 2012/
BIGGEST CONCERN THIS FORECAST PERIOD WOUND UP BEING FIRE WEATHER
CONCERNS FOR THURSDAY...WHICH IS BEGINNING TO BECOME QUITE THE
TRICKY FORECAST. WILL ALSO HAVE CONTINUED THUNDERSTORM CONCERNS
GOING INTO TONIGHT AND AGAIN TO END THE LABOR DAY WEEKEND.
GOOD WARM FRONT TAKING SHAPE THIS AFTERNOON IN TERMS OF A WIND
SHIFT EXTENDING FROM JUST NORTH OF SIOUX FALLS DOWN THROUGH
FAIRMONT. PERSISTENT THOUGH WEAK H85 FLOW HAS CONTINUED THE WAA AND
WEAK LIFT NORTH OF THE FRONT. 20Z MESO ANALYSIS SHOWS A NICE BAND OF
2000-3000 J/KG OF MUCAPE ALIGNED BASICALLY ALONG THE MN RIVER. THE
RAP CONTINUES TO HOLD THIS CAPE GRADIENT IN PLACE AT 00Z...WITH A
NICE BURST OF THETA-E ADVECTION TO THE EAST OF IT. THIS IS RIGHT
WHERE THE HRRR HAS BEEN DEVELOPING ROUND 2 OF CONVECTION THIS
EVENING FOR THE LAST SEVERAL RUNS BETWEEN 22Z AND 01Z.
SPCWRF/NMM/ARW REFLECTIVITY FORECASTS ALSO SHOW AGREEMENT WITH THE
HRRR FORECAST...THOUGH THEY ALL DIFFER WITH TIMING/PLACEMENT OF
INDIVIDUAL CELLS AS TO BE EXPECTED. BECAUSE OF THIS...INCREASED
POPS FOR THIS EVENING. EXPECT GREATEST COVERAGE OF STORMS THROUGH
3Z BEFORE FORCING BEGINS BENDING TO THE SOUTHEAST AND OUT OF THE
AREA. HOPEFULLY WE DO GET SOME RAIN...OTHERWISE SOUTH CENTRAL MN
COULD HAVE SOME SERIOUS PROBLEMS COME THURSDAY.
TONIGHT THROUGH WEDNESDAY. WARM FRONT BASICALLY WASHES OUT ALONG
I-94 WEDNESDAY AND LLJ LOSSES ITS DEFINITION...SO THIS SHOULD NOT
ONLY SHUT OFF THE PRECIP...BUT CLEAR THINGS OUT. FOR
WEDNESDAY...USED SOME MIX DOWN OF THE ECMWF TO TWEAK THE HIGHS
THAT DAY...THIS RESULTED IN A SLIGHT COOLING OF TEMPS EAST WITH
CONTINUED MID 90S WEST AS THE WARM BUBBLE WITH THE RIDGE DOES NOT
BEGIN MAKING SIGNIFICANT IN ROADS INTO THE MPX CWA UNTIL WEDNESDAY
NIGHT.
THURSDAY. THIS IS WHERE MUCH OF THE EFFORT WAS SPENT IN THE FORECAST
TODAY BETWEEN COORDINATION OF FIRE PRODUCTS WITH NEIGHBORING OFFICES
AND TRYING TO SORT OUT WHAT IS ENDING UP TO BE A TRICKY FORECAST.
ONE TREND FROM ALL 12Z GUIDANCE WITH THIS DAY IS THAT THEY ALL SPED
UP THE MOVEMENT OF THE WEAK BOUNDARY THAT WILL BE WORKING ACROSS
THE MPX CWA THAT AFTERNOON. THIS CAME AS A BIT OF A SURPRISE GIVEN
THE WALL OF SUBSIDENCE IT WILL BE RUNNING INTO WITH THE SUB-
TROPICAL RIDGE TO THE SOUTH. THERE IS ACTUALLY FAIRLY DECENT MODEL
CONSENSUS WITH THE FRONT SETTING UP FROM ROUGHLY SIOUX FALLS UP TO
EAU CLAIRE BY 7 PM THURSDAY. BESIDE THAT...BEHIND THIS
BOUNDARY...THE MID LEVEL TEMP GRADIENT LOOKS TO BE FAIRLY STRONG.
THIS HELPS TO INDUCE A DECENT UPPER JET ALONG THE INTERNATIONAL
BORDER /90 TO 100 KTS/. GIVEN THIS JET/TEMP GRADIENT SETUP...THE
NAM/GFS/ECMWF ARE STARTING TO PAINT A FAIRLY CLOUDY PICTURE NORTH
OF THE BOUNDARY /MID-UPPER LEVEL CLOUDS/...WHICH COULD REALLY TAKE
A BIG WHACK OUT OF EXPECTED HIGHS FOR THURSDAY...ESPECIALLY OVER
CENTRAL MN. GIVEN ALL OF THIS...DID NUDGE THE FORECAST HIGHS DOWN
ALONG AND NORTH OF A LINE FROM ROUGHLY REDWOOD FALLS...THROUGH THE
TWIN CITIES AND OVER TOWARD LADYSMITH. 925-850 MB THERMAL RIDGE
FORECAST BY THE ECMWF TO SIT ACROSS SOUTH CENTRAL MN OVER TOWARD
EAU CLAIRE...AND THIS IS WHERE IT STILL LOOKS QUITE PLAUSIBLE TO
SEE HIGHS TOP 100. WILL LEAVE THE HEAT WATCH FOR THE TWIN CITIES
AS IS...BUT WE MAY BE ABLE TO JUST GET AWAY WITH AN ADVY THERE ON
SOUTH GIVEN THE SLIGHT DOWNWARD NUDGE IN PROJECTED HIGHS WITH THIS
FORECAST.
AS FOR FIRE WEATHER CONCERNS...THEY ARE QUITE HIGH FOR THURSDAY AS
THIS IS A FAIRLY CLASSIC SETUP FOR SEEING SIGNIFICANT RED FLAG
WEATHER CONDITIONS IN THIS AREA /RH LESS THAN 25 PERCENT WITH
SUSTAINED WINDS IN EXCESS OF 20 MPH IN MN AND 15 MPH IN WI/. EXPECT
DEEP MIXING OUT AHEAD OF THE BOUNDARY...WHICH SHOULD HELP DEWPS MIX
DOWN INTO THE 50S. COMBINE DEWPS IN THE 50S WITH TEMPS UP NEAR 100
AND THE PROJECTED HUMIDITIES DROP INTO THE 20 TO 25 PERCENT RANGE.
THE BIGGER QUESTION MARK FOR THIS DAY WILL BE THE WINDS. AS THE
BOUNDARY SAGS INTO THE AREA...THE PRESSURE GRADIENT WILL SLACKEN
CONSIDERABLY WITH WIND SPEEDS DROPPING WELL BELOW THRESHOLDS NOTED.
HOWEVER...GET SUFFICIENTLY OUT AHEAD OF THE FRONT...AND WE SHOULD HAVE
NO PROBLEM MEETING AND EXCEEDING WIND THRESHOLDS...AS 1000-850 MB
MEAN WIND SPEEDS INCREASE INTO THE 20-30KT RANGE...WHICH WILL
SUPPORT SW WIND GUSTS UP TO 35 MPH. PROBABLY HAVE FIRE WEATHER WATCH
A LITTLE TOO FAR NORTH...BUT GIVEN MAGNITUDE OF FIRE WEATHER
PARAMETERS AND UNCERTAINTY IN FORECAST...FELT MORE COMFORTABLE WITH
A BIT OF A BUFFER TO THE NORTH.
FRIDAY THROUGH LABOR DAY. BIG QUESTION MARK HERE IS WHERE DO THE
REMNANTS FOR ISAAC END UP. FOR ONCE...GUIDANCE AT 12Z ACTUALLY IN
GOOD AGREEMENT WITH WHERE THE REMNANTS WILL GO AFTER LAND
FALL...TAKING THE REMNANT CIRCULATION UP INTO MO BY SATURDAY...THEN
OVER TOWARD CENTRAL INDIANA BY SUNDAY. MAIN IMPACT WITH THIS PATH IS
THAT ANY OF ITS MOISTURE WILL REMAIN SE OF THE MPX CWA...WITH THE
MPX CWA LIKELY BATTLING SUBSIDENCE TO THE NW OF ISAACS REMAINS SAT
THROUGH SAT NIGHT. GFS/ECMWF STILL SHOW A FRONT WORKING ACROSS THE
CWA SUNDAY/SUNDAY NIGHT...THOUGH WITH THE HURRICANE REMNANTS
SOUTHEAST...WOULD NOT BE AT ALL SURPRISED IF THIS SPEED SLOWS
DOWN IN THE COMING DAYS. IN ADDITION...THESE REMNANTS SHOULD
CONSUME A LOT OF THE MOISTURE THAT WOULD OTHERWISE BE DESTINED FOR
THE FRONT...MEANING CURRENT POPS FOR SUNDAY INTO MONDAY ARE
PROBABLY A BIT OVERDONE /EVEN AT THEIR CURRENT 30-40 PERCENT
LEVEL/. AS FOR TEMPERATURES...STILL LOOKS GOOD TO SEE A BIT OF A
COOL DOWN FOR FRIDAY...BUT HEAT SHOULD QUICKLY BUILD BACK IN AHEAD
OF THE FRONT FOR SATURDAY AND SUNDAY...WITH HIGHS IN THE 80S AND
90S CONTINUING TO BE COMMON THROUGH THE WEEKEND. NO SIGNS OF A
COOL DOWN ON THE ECMWF UNTIL THE MIDDLE OF NEXT WEEK.
&&
.AVIATION.../06Z TAF ISSUANCE/
STILL ANTICIPATING ELEVATED SHOWERS/TS TO DEVELOP AROUND/AFTER 06Z AS
SUPPORTED BY 925-850MB MOISTURE TRANSPORT PROGS IN VICINITY OF
THE STALLED BOUNDARY OVER SOUTHERN MN ACROSS WEST CENTRAL WI.
HOWEVER...SAID ACTIVITY IS EXPECTED TO OCCUR SOUTH OF THE TAF
SITES...WITH POSSIBLY THE EXCEPTION OF KRWF...WHERE A VICINITY
SHOWER MENTION HAS BEEN INCLUDED BRIEFLY AFTER 06Z. THE BOUNDARY
WILL ALSO SUPPLY A THREAT FOR FOG DEVELOPMENT OVERNIGHT...ALTHOUGH
SFC WINDS OF 5-10KTS SHOULD LIMIT THE POTENTIAL FOR SUB-MVFR
VSBYS. THE ONE EXCEPTION MAY BE AT KEAU...WHERE WINDS WILL BE
LOWER AROUND 3KTS AND DEWPOINTS ARE HOLDING IN THE LOWER 60S. HAVE
HELD ONTO A PERIOD OF IFR AROUND DAYBREAK AT KEAU. COULD ALSO SEE
SOME STRATUS CLOUDS DEVELOP ALONG/NORTH OF THE BOUNDARY
OVERNIGHT...ALTHOUGH CONFIDENCE IS STILL NOT HIGH SO HAVE KEPT
JUST A SCATTERED MENTION. AFTER 13Z WEDNESDAY...VFR CONDITIONS
WITH CLEARING SKIES ARE EXPECTED.
KMSP...ALTHOUGH THERE IS A CHANCE OF SHRA/TS DEVELOPMENT
OVERNIGHT...THE PROBABILITY IS LOW AND THE CHANCES ARE A BIT
HIGHER TO THE SOUTHWEST OF THE AIRFIELD. PATCHY FOG WITH MVFR
VSBYS MAY DEVELOP TOWARD DAYBREAK...BUT CONFIDENCE IS TOO LOW TO
INCLUDE WITH THE 06Z ISSUANCE. AFTER 12Z...HIGHER CONFIDENCE IN
VFR CONDITIONS THROUGH THE REMAINDER OF THE PERIOD. SE WINDS AT 7
TO 11 KNOTS THROUGH THE PERIOD.
/OUTLOOK FOR KMSP/
THURSDAY...VFR. WINDS SW AT 10 TO 15 KTS.
FRIDAY...VFR. WINDS E AT 5 TO 10 KTS.
SATURDAY....VFR. WINDS SE AT 5 TO 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR BLUE EARTH-BROWN-CARVER-DAKOTA-FARIBAULT-
FREEBORN-GOODHUE-HENNEPIN-LE SUEUR-MARTIN-MCLEOD-NICOLLET-
RAMSEY-REDWOOD-RENVILLE-RICE-SCOTT-SIBLEY-STEELE-WASECA-
WASHINGTON-WATONWAN.
EXCESSIVE HEAT WATCH FROM THURSDAY MORNING THROUGH THURSDAY
EVENING FOR HENNEPIN-RAMSEY.
WI...FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-ST. CROIX.
&&
$$
LS/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
638 PM CDT TUE AUG 28 2012
.AVIATION... /00Z TAF ISSUANCE/
TWO CONCERNS FOR THE UPCOMING TAF PERIOD AND BOTH ARE IN THE FIRST
12 HOURS. THERE IS A CONTINUED THREAT FOR SHOWER AND THUNDERSTORM
DEVELOPMENT THIS EVENING AHEAD OF THE NEARLY STATIONARY FRONT
ACROSS SOUTHERN MN. CONFIDENCE IS LOW ON THE LOCATION OF THE
INITIATION BUT SEVERAL SHORT TERM SOLUTIONS POINT TO THE TWIN
CITIES LATE IN THE EVENING WITH THE ACTIVITY SPREADING SOUTH
TOWARDS THE IOWA BORDER. LOW LEVEL FORCING WOULD POINT TO
SOUTHWEST MN WITH KRWF HAVING SOME CHANCE FOR AN ISOLATED SHOWER
OR THUNDERSTORM. HAVE HELD THE VCSH TO THIS SITE ONLY FOR NOW. THE
OTHER CONCERN TONIGHT IS THE POTENTIAL FOR FOG AND STRATUS ACROSS
CENTRAL MN AND WEST CENTRAL WI. 65 TO 70 DEG F DEW POINTS HAVE
POOLED IN THESE AREAS...PROBABLY AN ARTIFACT OF THE SHOWERS THAT
MOVED THROUGH EARLIER IN THE DAY. THE LOW LEVEL WIND FIELD WILL
ALSO BE BACKING TO AN EASTERLY DIRECTION AHEAD OF THE FRONT ACROSS
SOUTHERN MN. CONFIDENCE IS HIGH ON AT LEAST MVFR FOG FROM KAXN
THROUGH KSTC AND KRNH. LOCAL AFFECTS SURROUNDING KEAU SHOULD
YIELD IFR OR LOWER CONDITIONS FOR A FEW HOURS BEFORE SUNRISE.
CONFIDENCE IS NOT HIGH ON THE STRATUS DEVELOPMENT AND HAVE
INSERTED SCT005-009 AS AN INDICATOR OF THE POTENTIAL. WINDS ESE
TONIGHT AT LESS THAN 3-7 KNOTS BECOMING SE AROUND 10 KNOTS ON
WEDNESDAY.
KMSP...MAIN CONCERN IS SHOWER/THUNDERSTORM POTENTIAL IN THE 03Z-
06Z TIME FRAME. HAVE KEPT THE MENTION OUT WITH CONFIDENCE HIGHER
TO THE SOUTHWEST OF THE AIRFIELD. THERE IS A SMALL THREAT FOR MVFR
VISIBILITY TOWARD DAYBREAK. IF IT DOES OCCUR...EXPECT AN HOUR OR
TWO OF 5SM BR. OTHERWISE VFR CONDITIONS. WINDS SE 6 TO 9 KNOTS.
/OUTLOOK FOR KMSP/
THURSDAY...VFR. WINDS SW AT 10 TO 15 KTS.
FRIDAY...VFR. WINDS E AT 5 TO 10 KTS.
SATURDAY....VFR. WINDS SE AT 5 TO 10 KTS.
&&
.DISCUSSION... /ISSUED 413 PM CDT TUE AUG 28 2012/
BIGGEST CONCERN THIS FORECAST PERIOD WOUND UP BEING FIRE WEATHER
CONCERNS FOR THURSDAY...WHICH IS BEGINNING TO BECOME QUITE THE
TRICKY FORECAST. WILL ALSO HAVE CONTINUED THUNDERSTORM CONCERNS
GOING INTO TONIGHT AND AGAIN TO END THE LABOR DAY WEEKEND.
GOOD WARM FRONT TAKING SHAPE THIS AFTERNOON IN TERMS OF A WIND
SHIFT EXTENDING FROM JUST NORTH OF SIOUX FALLS DOWN THROUGH
FAIRMONT. PERSISTENT THOUGH WEAK H85 FLOW HAS CONTINUED THE WAA AND
WEAK LIFT NORTH OF THE FRONT. 20Z MESO ANALYSIS SHOWS A NICE BAND OF
2000-3000 J/KG OF MUCAPE ALIGNED BASICALLY ALONG THE MN RIVER. THE
RAP CONTINUES TO HOLD THIS CAPE GRADIENT IN PLACE AT 00Z...WITH A
NICE BURST OF THETA-E ADVECTION TO THE EAST OF IT. THIS IS RIGHT
WHERE THE HRRR HAS BEEN DEVELOPING ROUND 2 OF CONVECTION THIS
EVENING FOR THE LAST SEVERAL RUNS BETWEEN 22Z AND 01Z.
SPCWRF/NMM/ARW REFLECTIVITY FORECASTS ALSO SHOW AGREEMENT WITH THE
HRRR FORECAST...THOUGH THEY ALL DIFFER WITH TIMING/PLACEMENT OF
INDIVIDUAL CELLS AS TO BE EXPECTED. BECAUSE OF THIS...INCREASED
POPS FOR THIS EVENING. EXPECT GREATEST COVERAGE OF STORMS THROUGH
3Z BEFORE FORCING BEGINS BENDING TO THE SOUTHEAST AND OUT OF THE
AREA. HOPEFULLY WE DO GET SOME RAIN...OTHERWISE SOUTH CENTRAL MN
COULD HAVE SOME SERIOUS PROBLEMS COME THURSDAY.
TONIGHT THROUGH WEDNESDAY. WARM FRONT BASICALLY WASHES OUT ALONG
I-94 WEDNESDAY AND LLJ LOSSES ITS DEFINITION...SO THIS SHOULD NOT
ONLY SHUT OFF THE PRECIP...BUT CLEAR THINGS OUT. FOR
WEDNESDAY...USED SOME MIX DOWN OF THE ECMWF TO TWEAK THE HIGHS
THAT DAY...THIS RESULTED IN A SLIGHT COOLING OF TEMPS EAST WITH
CONTINUED MID 90S WEST AS THE WARM BUBBLE WITH THE RIDGE DOES NOT
BEGIN MAKING SIGNIFICANT IN ROADS INTO THE MPX CWA UNTIL WEDNESDAY
NIGHT.
THURSDAY. THIS IS WHERE MUCH OF THE EFFORT WAS SPENT IN THE FORECAST
TODAY BETWEEN COORDINATION OF FIRE PRODUCTS WITH NEIGHBORING OFFICES
AND TRYING TO SORT OUT WHAT IS ENDING UP TO BE A TRICKY FORECAST.
ONE TREND FROM ALL 12Z GUIDANCE WITH THIS DAY IS THAT THEY ALL SPED
UP THE MOVEMENT OF THE WEAK BOUNDARY THAT WILL BE WORKING ACROSS
THE MPX CWA THAT AFTERNOON. THIS CAME AS A BIT OF A SURPRISE GIVEN
THE WALL OF SUBSIDENCE IT WILL BE RUNNING INTO WITH THE SUB-
TROPICAL RIDGE TO THE SOUTH. THERE IS ACTUALLY FAIRLY DECENT MODEL
CONSENSUS WITH THE FRONT SETTING UP FROM ROUGHLY SIOUX FALLS UP TO
EAU CLAIRE BY 7 PM THURSDAY. BESIDE THAT...BEHIND THIS
BOUNDARY...THE MID LEVEL TEMP GRADIENT LOOKS TO BE FAIRLY STRONG.
THIS HELPS TO INDUCE A DECENT UPPER JET ALONG THE INTERNATIONAL
BORDER /90 TO 100 KTS/. GIVEN THIS JET/TEMP GRADIENT SETUP...THE
NAM/GFS/ECMWF ARE STARTING TO PAINT A FAIRLY CLOUDY PICTURE NORTH
OF THE BOUNDARY /MID-UPPER LEVEL CLOUDS/...WHICH COULD REALLY TAKE
A BIG WHACK OUT OF EXPECTED HIGHS FOR THURSDAY...ESPECIALLY OVER
CENTRAL MN. GIVEN ALL OF THIS...DID NUDGE THE FORECAST HIGHS DOWN
ALONG AND NORTH OF A LINE FROM ROUGHLY REDWOOD FALLS...THROUGH THE
TWIN CITIES AND OVER TOWARD LADYSMITH. 925-850 MB THERMAL RIDGE
FORECAST BY THE ECMWF TO SIT ACROSS SOUTH CENTRAL MN OVER TOWARD
EAU CLAIRE...AND THIS IS WHERE IT STILL LOOKS QUITE PLAUSIBLE TO
SEE HIGHS TOP 100. WILL LEAVE THE HEAT WATCH FOR THE TWIN CITIES
AS IS...BUT WE MAY BE ABLE TO JUST GET AWAY WITH AN ADVY THERE ON
SOUTH GIVEN THE SLIGHT DOWNWARD NUDGE IN PROJECTED HIGHS WITH THIS
FORECAST.
AS FOR FIRE WEATHER CONCERNS...THEY ARE QUITE HIGH FOR THURSDAY AS
THIS IS A FAIRLY CLASSIC SETUP FOR SEEING SIGNIFICANT RED FLAG
WEATHER CONDITIONS IN THIS AREA /RH LESS THAN 25 PERCENT WITH
SUSTAINED WINDS IN EXCESS OF 20 MPH IN MN AND 15 MPH IN WI/. EXPECT
DEEP MIXING OUT AHEAD OF THE BOUNDARY...WHICH SHOULD HELP DEWPS MIX
DOWN INTO THE 50S. COMBINE DEWPS IN THE 50S WITH TEMPS UP NEAR 100
AND THE PROJECTED HUMIDITIES DROP INTO THE 20 TO 25 PERCENT RANGE.
THE BIGGER QUESTION MARK FOR THIS DAY WILL BE THE WINDS. AS THE
BOUNDARY SAGS INTO THE AREA...THE PRESSURE GRADIENT WILL SLACKEN
CONSIDERABLY WITH WIND SPEEDS DROPPING WELL BELOW THRESHOLDS NOTED.
HOWEVER...GET SUFFICIENTLY OUT AHEAD OF THE FRONT...AND WE SHOULD HAVE
NO PROBLEM MEETING AND EXCEEDING WIND THRESHOLDS...AS 1000-850 MB
MEAN WIND SPEEDS INCREASE INTO THE 20-30KT RANGE...WHICH WILL
SUPPORT SW WIND GUSTS UP TO 35 MPH. PROBABLY HAVE FIRE WEATHER WATCH
A LITTLE TOO FAR NORTH...BUT GIVEN MAGNITUDE OF FIRE WEATHER
PARAMETERS AND UNCERTAINTY IN FORECAST...FELT MORE COMFORTABLE WITH
A BIT OF A BUFFER TO THE NORTH.
FRIDAY THROUGH LABOR DAY. BIG QUESTION MARK HERE IS WHERE DO THE
REMNANTS FOR ISAAC END UP. FOR ONCE...GUIDANCE AT 12Z ACTUALLY IN
GOOD AGREEMENT WITH WHERE THE REMNANTS WILL GO AFTER LAND
FALL...TAKING THE REMNANT CIRCULATION UP INTO MO BY SATURDAY...THEN
OVER TOWARD CENTRAL INDIANA BY SUNDAY. MAIN IMPACT WITH THIS PATH IS
THAT ANY OF ITS MOISTURE WILL REMAIN SE OF THE MPX CWA...WITH THE
MPX CWA LIKELY BATTLING SUBSIDENCE TO THE NW OF ISAACS REMAINS SAT
THROUGH SAT NIGHT. GFS/ECMWF STILL SHOW A FRONT WORKING ACROSS THE
CWA SUNDAY/SUNDAY NIGHT...THOUGH WITH THE HURRICANE REMNANTS
SOUTHEAST...WOULD NOT BE AT ALL SURPRISED IF THIS SPEED SLOWS
DOWN IN THE COMING DAYS. IN ADDITION...THESE REMNANTS SHOULD
CONSUME A LOT OF THE MOISTURE THAT WOULD OTHERWISE BE DESTINED FOR
THE FRONT...MEANING CURRENT POPS FOR SUNDAY INTO MONDAY ARE
PROBABLY A BIT OVERDONE /EVEN AT THEIR CURRENT 30-40 PERCENT
LEVEL/. AS FOR TEMPERATURES...STILL LOOKS GOOD TO SEE A BIT OF A
COOL DOWN FOR FRIDAY...BUT HEAT SHOULD QUICKLY BUILD BACK IN AHEAD
OF THE FRONT FOR SATURDAY AND SUNDAY...WITH HIGHS IN THE 80S AND
90S CONTINUING TO BE COMMON THROUGH THE WEEKEND. NO SIGNS OF A
COOL DOWN ON THE ECMWF UNTIL THE MIDDLE OF NEXT WEEK.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR BLUE EARTH-BROWN-CARVER-DAKOTA-FARIBAULT-
FREEBORN-GOODHUE-HENNEPIN-LE SUEUR-MARTIN-MCLEOD-NICOLLET-
RAMSEY-REDWOOD-RENVILLE-RICE-SCOTT-SIBLEY-STEELE-WASECA-
WASHINGTON-WATONWAN.
EXCESSIVE HEAT WATCH FROM THURSDAY MORNING THROUGH THURSDAY
EVENING FOR HENNEPIN-RAMSEY.
WI...FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-ST. CROIX.
&&
$$
RAH/MPG
AREA FORECAST DISCUSSION...RESENT
NWS TWIN CITIES/CHANHASSEN MN
434 AM CDT MON AUG 27 2012
.DISCUSSION...
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT.
HIGH PRESSURE IS SETTLING SOUTHEAST ACROSS THE CWA EARLY THIS
MORNING. DRIER AIR HAS INVADED THE AREA WITH PW VALUES RANGING
FROM 0.5 TO 0.75 INCHES. TODAY WILL BE THE LAST MILD DAY FOR A
WHILE. LIGHT NORTHWESTERLY FLOW WILL KEEP DEW POINTS CONFINED TO
THE MID 50S...WHICH STILL MAY BE A BIT HIGH IF WE CAN MIX A BIT
HIGHER THAN CURRENT FORECAST SOUNDINGS SUGGEST. THIS FALLS WITHIN
THE HIGHER MAV MOS DEW POINTS /NEAR 60/ AND THE LOWER MET MOS
/UPPER 40S/. EITHER SOLUTION TENDS TO BE ON THE TOO MOIST OR TOO
DRY SIDE. HIGHS TODAY MAY BE A DEGREE OR SO COOLER THAN YESTERDAY
WITH 925 MB TEMPS OF +21C NORTHEAST TO +24 SOUTHWEST...OR LOWER
80S TO UPPER 80S...RESPECTIVELY.
HIGH PRESSURE SLIDES TO THE EAST TO THE GREAT LAKES TONIGHT.
MEANWHILE...A FAIRLY WELL-DEFINED WARM FRONT WILL DEVELOP FROM THE
SD/NE BORDER ESE ACROSS NRN IA. IN ADDITION...THE 850MB JET IS
EXPECTED TO STRENGTHEN BENEATH THE EML TO 20 TO 30 KTS ACROSS SRN
SD. NAM IS MUCH MORE BULLISH AT 35 TO 40 KTS NOSING INTO SWRN MN.
FINALLY...RAPID MOISTENING ALONG THE 310-315K SURFACES...AND DECENT
ISENTROPIC UPGLIDE...SHOULD BE ENOUGH TO SUSTAIN AT LEAST A LITTLE
ELEVATED THUNDERSTORM ACTIVITY LATE TONIGHT ACROSS SOUTHWEST AND
SOUTH CENTRAL MN. STORMS WOULD MOST LIKELY FORM OVER ERN SD AND
DRIFT SOUTHEAST ALONG THE FRONT. STEEP MID LEVEL LAPSE RATES MAY
PROMOTE A LITTLE HAIL WITH SOME STORMS AS WELL. MOS POPS APPEAR
TOO LOW IN THIS SITUATION...AND EVEN NAM/GFS/ECMWF DETERMINISTIC
MODELS PAINT SOME QPF IN THESE AREAS LATE TONIGHT SO WILL
INTRODUCE SCHC POPS FOR NOW.
THE WARM FRONT WILL BEGIN TO LIFT NORTHEAST TUESDAY...BUT PROBABLY
WON/T REACH THE I-94 CORRIDOR. HOTTER TEMPERATURES ARE EXPECTED
WITH WAA BEGINNING TO REALLY KICK IN...ESPECIALLY SOUTH OF THE
FRONT. A FEW STORMS REMAIN POSSIBLE ALONG THE FRONT...PRIMARILY IN
THE MORNING BEFORE THE LLJ WEAKENS. STORMS SHOULD REMAIN ISOLATED
WITH CAP AT 850 MB NOT LIKELY TO BREAK TUESDAY AFTERNOON.
COULD SEE A FEW MORE STORMS TUESDAY NIGHT AS THE LLJ RAMPS UP
AGAIN...BUT THE JET IS ORIENTED MORE WSW/ENE AND NOT
PERPENDICULAR TO THE FRONT. THUS...LEFT POPS OUT FOR NOW TUESDAY
NIGHT.
.LONG TERM...WEDNESDAY THROUGH SUNDAY.
THE HEAT IS REALLY ON FOR MID TO LATE WEEK AS A LARGE INTENSE RIDGE
BUILDS ACROSS THE UPPER MIDWEST. NAM AND DGEX CONTINUE TO BE
INCREDIBLY HOT WITH 850 MB TEMPS ON THE ORDER OF +30C AND 925 MB
TEMPS OF +38C. 2 METER HIGH TEMPS OFF BOTH MODELS ARE IN EXCESS OF
110 DEGREES IN PLACES WHICH WOULD CRUSH EVEN ALL-TIME RECORDS.
LUCKILY THE MAGNITUDE OF THIS HEAT SHOULD NOT APPROACH THESE VALUES
SINCE BOTH MODELS HAVE BEEN TOO HOT FOR MUCH OF THE SUMMER AND TEND
TO MIX THE ATMOSPHERE TO AN EXTREME DEGREE. HOWEVER...THE ECMWF
CONTINUES ITS TREND UPWARD WITH TEMPERATURES WEDNESDAY AND THURSDAY
AND NOW HAS 925 MB TEMPS APPROACH +29 TO +32C WITHIN THE THERMAL
RIDGE SETTLING OVERHEAD THURSDAY. GFS REMAINS AN EXTREME COLD
OUTLIER. GIVEN THAT THE COOLEST REASONABLE MODEL /ECMWF/ NOW
SUPPORTS HIGHS IN THE 92 TO 102 DEGREE RANGE FOR THIS
PERIOD...CONTINUED TO BUMP TEMPS UP INTO THE MID AND UPPER 90S BY
THURSDAY. EVEN HAVE SOME TEMPS EXCEEDING 100F OVER SWRN MN BUT IT
COULD BE WARMER STILL.
SERIOUSLY CONSIDERED ISSUING AN EXCESSIVE HEAT WATCH FOR WEDNESDAY
AND THURSDAY FOR THE MSP METRO...BUT HELD OFF BASED ON UNCERTAINTIES
WITH AFTERNOON DEW POINTS AND MIXING POTENTIAL AND IT IS STILL
BEYOND THE 4TH PERIOD. FUTURE SHIFTS WILL NEED TO REEVALUATE THIS
POSSIBILITY.
THE HEART OF THE RIDGE WILL SINK SOUTH A BIT FOR FRIDAY AND
SATURDAY...BUT HIGHS IN THE 90S ARE STILL EXPECTED SOUTH OF I-94
BOTH DAYS.
THEN EYES TURN TO THE REMNANTS OF ISAAC WHICH MODELS CONTINUE TO
SHIFT NORTHWESTWARD WITH EACH RUN. CONSENSUS AND THE OFFICIAL NHC
TRACK NOW BRING IT INTO CENTRAL MISSOURI BY FRIDAY NIGHT BEFORE A
LIKELY RECURVATURE INTO THE LOWER GREAT LAKES BY SUNDAY AFTERNOON. A
FRONT WILL BE SAGGING SOUTH INTO THE CWA SATURDAY NIGHT AND SUNDAY
WITH SOUTHERLY FLOW EXPECTED TO WICK SOME OF ISAAC/S AMPLE MOISTURE
NORTHWARD. INTRODUCED A SLIGHT CHANCE OF TSRA WITH THE FRONT SUNDAY
FOR NOW BUT WILL NEED TO WATCH FOR EXCESSIVE RAINFALL FROM A
POTENTIAL "PREDECESSOR RAIN EVENT" SOMEWHERE IN THE UPPER MIDWEST
FROM ISAAC.
BORGHOFF
&&
.AVIATION.../00Z TAF ISSUANCE/
ONLY PROBLEM IN THE OVERNIGHT IS THE POTENTIAL FOR RADIATION FOG.
STILL HAVE SOME HIGHER DEWPOINTS OFF TOT EH SOUTH AND EAST...AND
WINDS ARE RATHER LIGHT WITH HIGH PRESSURE RIDGE IN PLACE. RAP AND
TO A LESSER DEGREE THE 00Z NAM WAS INDICATING SOME POTENTIAL FOR AT
LEAST SOME MVFR FOG. WILL MENTION THAT AT ALL BUT KAXN/KMSP FOR
NOW. KEAU MAY GO DOWN MORE SO DID GO IFR THERE AFTER 10Z. SHOULD
BURN OFF QUICKLY MONDAY MORNING AND SUNSHINE EXPECTED MST OF THE
DAY. THE NAM CONTINUES TO INDICATE SOME POTENTIAL OF MID LEVEL
CLOUDS DEVELOPING LATER MONDAY NIGHT. OVER WESTERN AREAS. WILL
MENTION SOME BASED AC THERE INTO THE EVENING. OTHERWISE VFR AFTER
POSSIBLE FOG TONIGHT. SURFACE WINDS WILL REMAIN LIGHT OVERNIGHT
BECOMING NORTHWEST TO NORTH AND EVENTUALLY NORTHEAST AND THEN
SOUTHEAST OVER WESTERN TAF SITES INTO MONDAY NIGHT. SHOULD REMAIN
LESS THAN 10 KTS.
KMSP...VFR SKC OVERNIGHT THROUGH MONDAY. LIGHT/VARIABLE WIND
OVERNIGHT BECOMING NORTHWEST/NORTH MONDAY AND EVENTUALLY EAST INTO
MONDAY NIGHT. WILL REMAIN BELOW 10 KNOTS.
/OUTLOOK FOR KMSP/
TUESDAY...VFR. WINDS SE AT 5 TO 10 KTS.
WEDNESDAY...VFR. WINDS SW AT 10G15KTS.
THURSDAY...VFR. WINS SSW AT 10G15KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
BORGHOFF/DE
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1146 PM CDT SUN AUG 26 2012
.UPDATE...
ISSUED AT 852 PM CDT SUN AUG 26 2012
THERE HAS BEEN AN OVERALL DECREASE IN AREA COVERAGE FOR -SHRA/ISOLD
-TSRA OVER THE PAST 1-2 HOURS NOW THAT THE SUN HAS SET AND THE
THROUGH AXIS HAS ENTERED THE NORTHWEST PART OF THE CWA. HAVE
CONTINUED LIKELY POPS OVER THE SRN AND ERN PARTS OF THE CWA INTO
THE OVERNIGHT HOURS WHERE THE RAP IS SHOWING DECENT LOW LEVEL
MOISTURE CONVERGENCE JUST AHEAD OF THE TROUGH. HAVE ALSO BEGAN TO
TRIM BACK ON RAIN CHANCES BEHIND THE TROUGH AXIS. OTHERWISE...
GOING FORECAST LOOKS ON TRACK AND ONLY MADE MINOR TWEAKS TO IT
BASED ON CURRENT TRENDS.
BRITT
&&
.SHORT TERM...
ISSUED AT 237 PM CDT SUN AUG 26 2012
(TONIGHT AND MONDAY)
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TONIGHT
AS MID LEVEL TROF AND SURFACE TROF INTERACT WITH A VERY MOISTURE
RICH ATMOSPHERE. LOCALLY HEAVY DOWNPOURS WILL BE POSSIBLE...BUT
SEVERE WEATHER IS UNLIKELY GIVEN LIMITED INSTABILITY.
THIS AXIS OF RAINFALL WILL SLOWLY SHIFT SOUTHEAST AS DRIER AIR
MOVES IN FROM THE NORTH THANKS TO A SURFACE HIGH. WARMEST
TEMPERATURES ON MONDAY WILL BE NORTH OF INTERSTATE 70 THANKS TO
AFTERNOON SUNSHINE...AND COOLEST SOUTH WHERE CLOUD COVER AND SCT
CONVECTION WILL GRADUALLY COME TO AN END.
CVKING
&&
.LONG TERM...
ISSUED AT 237 PM CDT SUN AUG 26 2012
(TUESDAY THROUGH SUNDAY)
UPPER LEVEL RIDGE WILL BUILD INTO THE MIDWEST WITH SLIGHTLY ABOVE
NORMAL TEMPERATURES EXPECTED THROUGH THURSDAY. HAVE FOLLOWED
LATEST NATIONAL HURRICANE CENTER FORECAST AND HPC GUIDANCE FOR THE
EXTENDED FORECAST WITH THE REMNANTS OF ISAAC BRUSHING THE EASTERN
HALF OF THE CWA LATE THIS WEEK AND EARLY NEXT WEEKEND. CHANGES IN
THE FORECAST INCLUDE CHANCE POPS AND COOLER TEMPERATURES FOR THE
SOUTHEAST HALF OF THE CWA. THIS CHANGE IN THE FORECAST IS DUE TO
THE TRACK OF THE HURRICANE BEING SHIFTED 150 MILES TO THE WEST
OVER THE PAST 24 HOURS BY NHC. MORE CHANGES ARE LIKELY IN THE
TRACK AND THIS WILL OBVIOULSY HAVE A BIG IMPACT ON OUR WEATHER
LATE THIS WEEK AND NEXT WEEKEND. SO STAY TUNED.
CVKING
&&
.AVIATION...
ISSUED AT 1140 PM CDT SUN AUG 26 2012
850 FRONT/TROF APPEARS TP BE BETWEEN QUINCY AND ST. LOUIS. THERE
WERE A FEW ALONG THIS FEATURE BUT THEY ARE DYING. MAIN BAND OD
SHOWERS HAS MOVED SOUTH OF ALL TERMINAL. MAIN ISSUE TONIGHT WILL
BE DEVELOPMENT OF FOG AND STRATUS. SATELLITE SHOWER AREA OF STATUS
DEVELOPING OVER WEST CENTRAL ILLINOIS SPREADING TO THE SOUTH.
EXPEDT THIS TREND TO CONTINUE. GIVER LIGHT NORTH SURFACE WIND
EXPECT FOG AND STRATUS TO HOLD ON UNTIL ABOUT 18Z MONDAY.
SPECIFICS FOR KSTL...AS MID CLOUD DECK CLEAR EXPECT TO SEE SOME
FOG DEVELOP. STARTUS SHOULD ALSO BUILD IN FROM THE NORTH. WITH A
LIGHT NORTHERLY WIND BELIEVE THE FOG/STRTUS MAY HOLD ON UNTIL
ABOUT 18Z MONDAY. CLEARING MONDAY NIGHT WITH SOME FOG DEVELOPING
AGAIN TUESDAY MORNING.
JPK
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
613 PM CDT TUE AUG 28 2012
.AVIATION...
00Z TAFS FOR KOFK...KOMA AND KLNK.
VFR CONDITIONS ARE EXPECTED THROUGH 30/00Z. SSW SURFACE WINDS
SHOULD RELAX SOME TONIGHT BUT SHOULD PICK UP AGAIN BY MID
WEDNESDAY MORNING. IF WINDS DECOUPLE MORE THAN EXPECTED TONIGHT AT
KOFK VICINITY...A LOW LEVEL WIND SHEAR COULD DEVELOP AND TRENDS
WILL BE MONITORED.
CHERMOK
&&
.PREV DISCUSSION... /ISSUED 308 PM CDT TUE AUG 28 2012/
DISCUSSION...
FORECAST CONCERNS CENTER AROUND HOT TEMPS...FIRE WEATHER
CONDITIONS...AND REMNANTS OF ISAAC.
LATEST WATER VAPOR IMAGERY AND 500MB RAP ANALYSIS SHOWS LARGE DOME
OF HIGH PRESSURE OVER THE CENTRAL CONUS WITH A WEAK IMPULSE ON TOP
RIDING OVER THE RIDGE OVER SOUTHEASTERN WYOMING. UPSTREAM...A
SHORTWAVE TROF CONTINUES TO MOVE ONTO THE WEST COAST. AT THE
SFC...WARM SOUTHWESTERLY FLOW EXTENDS OVER ALL OF THE FORECAST
AHEAD OF SFC LOW PRESSURE CENTERED OVER CENTRAL SOUTH DAKOTA.
ACCAS FIELD REMAINS OVER OUR NORTHERN COUNTIES WHERE MID LEVEL
MOISTURE IS PROGGED TO REMAIN OVERNIGHT AND INTO WEDNESDAY. SOME
VERTICAL MOTION IS PROGGED OVER THIS SAME AREA OVERNIGHT AS ERN
WYOMING WAVE RIDES THE RIDGE TOWARD THE AREA. WITH EXTREMELY DRY
LEVELS BELOW 650MB...DO NOT EXPECT ANY PCPN TO REACH THE GROUND IF
ANY CAN/DOES DEVELOP.
FOCUS THEN TURNS TO FIRE WEATHER CONDITIONS ACROSS OUR NORTHERN
COUNTIES WEDNESDAY AFTERNOON. RED FLAG WARNING CRITERIA WILL BE
VERY CLOSE...ESPECIALLY IF WE CAN MIX OUT OUR SFC DEWPOINTS. WITH
MODEST SOUTHWESTERLY LOW LEVEL FLOW...WE SHOULD MIX OUT TEMPS QUITE
WELL DURING THE AFTERNOON PUSHING HIGHS INTO THE LOWER 100S IN
OUR NORTH TO THE UPPER 90S ELSEWHERE. DO EXPECT SIMILAR READINGS
ON THURSDAY AS 850MB TEMPS AROUND THE SAME IN THE UPPER 20S WITH
STRONG SOUTHWESTERLY MIXING. AS A RESULT...WILL GO WITH A RED FLAG
WARNING IN THE NORTHWEST COUNTIES AND MAY NEED TO CONSIDER A
HEADLINE OF SORTS FOR THURSDAY AS WELL.
MODEL CONSENSUS BRINGS ISAAC REMNANTS AS FAR NORTH AS OUR
SOUTHEASTERN TIER OF COUNTIES FRIDAY NIGHT INTO SATURDAY. AS A
RESULT...HAVE ADDED LOW POPS...INCREASED SKY COVER AND LOWERED
HIGHS SLIGHTLY. THIS SYSTEM WILL QUICKLY DRIFT EAST OF THE AREA
AND SOUTHWESTERLY UPPER LEVEL FLOW WILL FOLLOW WITH A FEW EMBEDDED
SHORTWAVES PROGGED TO TRAVEL ACROSS THE REGION. AS A RESULT...HAVE
CONTINUED SOME SMALL CHANCE POPS DAYS 6 & 7 BUT CONFIDENCE IS
FAIRLY LOW.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...RED FLAG WARNING FROM 1 PM TO 9 PM CDT WEDNESDAY FOR NEZ011-012-
015>018-030>033-042.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
736 AM CDT MON AUG 27 2012
.UPDATE...JUST COMPLETED AN UPDATE MAINLY TO ADD 20-30 PERCENT
SHOWER/ISOLATED STORM COVERAGE TO THE MAJORITY OF SOUTH CENTRAL
NEBRASKA THROUGH 15Z...WHICH MAY NOT BE LONG ENOUGH BUT ITS A
START. SINCE 11Z OR SO...ELEVATED SHOWERS AND A FEW STORMS HAVE
MOVED INTO OR DEVELOPED OVER MAINLY THE NORTHWEST QUADRANT OF THE
CWA. ALTHOUGH THIS ACTIVITY WAS NOT WELL-ANTICIPATED EVEN 12 HOURS
AGO...THE LATEST TRENDS FROM THE RAP MODEL INDICATE A PRONOUNCED
THETA-E GRADIENT EVIDENT ACROSS THE CWA AT 700MB...WITH MODEST
THETA-E ADVECTION/MID LEVEL CONVERGENCE SPARKING THIS FAIRLY
CLASSIC CASE OF SUNRISE SURPRISE ACTIVITY. THE JURY IS OUT ON HOW
LONG SOME OF THIS PRECIP MIGHT LAST...BUT THE LATEST HRRR KEEPS AT
LEAST SOMETHING GOING INTO THE EARLY AFTERNOON HOURS...SO WILL
DEFER TO ONCOMING DAY SHIFT TO EXTEND THESE POPS BEYOND 15Z IF
NECESSARY. NOT EXPECTING ANYTHING SEVERE...ALTHOUGH SUPPOSE SOME
PEA SIZE HAIL IS NOT OUT OF THE QUESTION WITH MUCAPE POTENTIALLY
IN EXCESS OF 500 J/KG. AS FOR FOG TRENDS...A FEW ISOLATED POCKETS
OF DENSE FOG HAVE BEEN REPORTED IN THE EASTERN CWA...BUT NOWHERE
NEAR WIDESPREAD ENOUGH TO CONSIDER AN ADVISORY WITH MOST AREAS
WELL ABOVE 1 MILE. DID HOWEVER ADD SOME 1 MILE OR LESS WORDING TO
THE ZONE FORECAST TO ACKNOWLEDGE THE SPOTTY LOWER VISIBILITIES OUT
THERE FOR THE NEXT FEW HOURS. NO OTHER CHANGES MADE AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 639 AM CDT MON AUG 27 2012/
AVIATION...12Z KGRI TAF. ALTHOUGH VFR VISIBILITY/CEILING AND
PRECIPITATION-FREE CONDITIONS ARE FORECAST THROUGH THE VAST
MAJORITY OF THE PERIOD...THE FIRST FEW HOURS RIGHT AWAY THIS
MORNING COULD POSE A FEW ISSUES. FIRST OFF...WILL CONTINUE TO
CARRY A TEMPO GROUP THROUGH 14Z TO COVER THE POSSIBILITY OF A
BRIEF MVFR VISIBILITY RESTRICTION...AS LIGHT FOG HAS BEEN REPORTED
AT NEARBY STATIONS THIS MORNING. SECONDLY...A SOMEWHAT UNEXPECTED
NARROW CORRIDOR OF SHOWERS/WEAK THUNDERSTORMS IS CURRENTLY LOCATED
WITHIN 40 MILES WEST-NORTHWEST OF KGRI...AND IS SHOWING SOME SIGNS
OF WORKING EAST TOWARD THE TERMINAL. FOR NOW...WILL INTRODUCE A
VICINITY THUNDERSTORM MENTION THROUGH 15Z ALTHOUGH ANY STORMS THAT
MIGHT AFFECT THE TERMINAL SHOULD PRODUCE LITTLE MORE THAN A BRIEF
DOWNPOUR. BEYOND THESE INITIAL CONCERNS THIS MORNING...THE TIME
FRAME BETWEEN LATE THIS MORNING THROUGH THE OVERNIGHT HOURS
SHOULD BE PRECIPITATION AND FOG-FREE...AS SOUTHERLY SUSTAINED
BREEZES AVERAGE NO MORE THAN 10-12KT. AT THIS TIME...ANY LATE
AFTERNOON/EVENING THUNDERSTORMS ARE EXPECTED TO FOCUS AT LEAST 100
MILES NORTHWEST OF KGRI.
PREV DISCUSSION... /ISSUED 547 AM CDT MON AUG 27 2012/
SHORT TERM...TODAY THROUGH 12Z THURSDAY.
BIGGEST CHALLENGE WILL BE POSSIBLE SHOWERS AND THUNDERSTORMS FOR
PART OF THE AREA THIS MORNING.
GENERAL SCENARIO OF THE UPPER RIDGE BUILDING INTO THE REGION IS THE
DOMINANT FEATURE FOR OUR AREA.
A THIN RIBBON OF CONVECTION IS BEGINNING TO DEVELOP JUST TO THE
NORTHWEST OF THE CWA. THIS APPEARS TO BE OCCURRING FROM SOME WEAK
THETA-E ADVECTION IN MID-LEVELS. ORIGINALLY I THOUGHT THAT PERHAPS
THETA-E ADVECTION HAD SUBSIDED ENOUGH SO THAT THE REGION WOULD BE
DRY. EARLIER CONVECTION ACROSS PARTS OF WESTERN AND CENTRAL NEBRASKA
OVERNIGHT LAST NIGHT DIED OUT AS IT ENTERED OUR CWA...BUT THIS NEW
BATCH SEEMS TO BE WAXING...AND PERHAPS STRENGTHENING AND BUILDING
TOWARD OUR CWA. THIS WILL NEED TO BE MONITORED THIS MORNING FOR A
POTENTIAL UPDATE. SEVERE WEATHER DOES NOT APPEAR TO BE AN ISSUE IN
THIS CASE. THIS SHOULD DIE OFF BY MID-MORNING...WHEREVER IT DECIDES
TO END UP.
THE MORNING FOG...ESPECIALLY IN THE EASTERN CWA...SHOULD BURN OFF
SHORTLY AFTER SUNRISE AS SUBSIDENCE IS SIGNIFICANT.
ANOTHER PROBLEM IN THE SHORT TERM IS THE POTENTIAL FOR ELEVATED FIRE
DANGER...ESPECIALLY IN WESTERN AREAS OF THE CWA WITH RELATIVE
HUMIDITY DECREASING TO NEAR 20 PERCENT AND SUSTAINED WIND SPEEDS
POSSIBLY GETTING CLOSE TO 20 MPH. COULD BE A CLOSE ONE ON EITHER DAY.
MADE MINOR TWEAKS TO TEMPERATURE AND DEWPOINTS USING RECENT
VERIFICATION DATA AS A TOOL. GENERALLY COOLED DOWN MAXIMUM
TEMPERATURES A TAD FOR TUESDAY AND WEDNESDAY.
LONG TERM...THURSDAY DAYTIME THROUGH SUNDAY DAYTIME. OVERALL...VERY
LITTLE CHANGE MADE TO THESE 4 DAYS FROM PREVIOUS FORECAST...WHICH
APPEAR TO BE HIGHLIGHTED BY AT LEAST SLIGHTLY ABOVE NORMAL TEMPS AND
DRY CONDITIONS. THAT BEING SAID...AT LEAST A SLIGHT RAIN MENTION MAY
ULTIMATELY PROVE NECESSARY FOR THE SAT NIGHT/SUNDAY TIME FRAME...BUT
WITH THIS POSSIBILITY STILL BEING 5-6 DAYS OUT WILL MAINTAIN THE
PRECIP-FREE MENTION FOR NOW. LOW TEMPERATURES THROUGH THIS PERIOD
ARE FORECAST TO AVERAGE LOW-MID 60S.
STARTING OFF THURSDAY/THURSDAY NIGHT...00Z ECMWF/GFS RUNS ARE IN
DECENT AGREEMENT ON THE BIG PICTURE ALOFT...WITH A BROAD
WEST-SOUTHWEST TO EAST-NORTHEAST ORIENTED RIDGE DOMINATING THE LOCAL
AREA AND IN THEORY KEEPING THINGS CAPPED OFF TO CONVECTION. THE
CENTRAL PLAINS LIES BETWEEN A TROUGH OVER THE NORTHERN
ROCKIES/PACIFIC NORTHWEST...AND THE REMNANTS OF TROPICAL SYSTEM
ISAAC WHICH ARE GENERALLY PROGGED TO TRACK FROM THE SOUTHERN LA/MS
AREA THURSDAY MORNING TO ARKANSAS AND VICINITY BY FRIDAY MORNING.
BACK HOME...THE DAYTIME HOURS THURSDAY COULD BE A TOUCH BREEZY
ESPECIALLY ACROSS THE NORTHWEST 1/2 OF THE CWA...AS A WEAK LOW
PRESSURE SYSTEM PASSING OFF TO THE NORTH KEEPS SOUTH/SOUTHWEST
SURFACE FLOW IN PLACE. FOR HIGH TEMPS...KEPT THE ENTIRE CWA IN THE
LOW-MID 90S. AT LEAST FOR NOW...HAVE MINIMUM AFTERNOON RELATIVE
HUMIDITY VALUES ABOVE 20 PERCENT ALL AREAS...BUT HAVE SEVERAL FAR
WESTERN COUNTIES AS LOW AS THE MID 20S...SO AT LEAST SOME ELEVATED
FIRE DANGER NOT OUT OF THE QUESTION. WITH MORE IMMEDIATE AND
POTENTIALLY ELEVATED FIRE DANGER ISSUES IN THE SHORT TERM PERIOD
TUESDAY-WEDNESDAY...WILL HOLD OFF ON ANY FIRE WEATHER MENTION FOR
THURSDAY IN THE HAZARDOUS WEATHER OUTLOOK AT THIS TIME.
FRIDAY/FRIDAY NIGHT...KEPT THE DRY FORECAST GOING...AS ANY NORTHERN
STREAM DISTURBANCES REMAIN WELL OFF TO THE NORTH/NORTHWEST OF THE
AREA...WHILE THE ECMWF/GFS CONSENSUS FOR THE ISAAC REMNANTS IS TO
BRING THEM UP INTO MISSOURI AND VICINITY...KEEPING ANY ASSOCIATED
PRECIP NO CLOSER TO THE CWA THAN FAR EASTERN KS IF THIS TRACK HOLDS.
WITH A BIT WEAKER SURFACE GRADIENT VERSUS THURSDAY...NOT EXPECTING
ELEVATED FIRE DANGER TO BE MUCH OF AN ISSUE...BUT KEPT HIGH TEMPS
SEVERAL DEGREES ABOVE NORMAL WITH OF THE CWA IN THE 90-92 RANGE.
SATURDAY/SAT NIGHT...ANTICIPATE THE BROAD RIDGE OVER THE CWA TO
FLATTEN A BIT...AS FLOW TURNS MORE ZONAL IN RESPONSE TO A FAIRLY
VIGOROUS SHORTWAVE CROSSING FAR SOUTH CENTRAL CANADA.
MEANWHILE...ISAAC REMNANTS ARE STILL EXPECTED TO BE A NON-ISSUE
LOCALLY AS THEY ARE SHUNTED NORTHEAST ACROSS THE IL/IN AREA. WHILE
CONFIDENCE IS REASONABLY HIGH IN A DRY DAYTIME PERIOD...COULD
FORESEE SOME SLIGHT POPS EVENTUALLY NECESSITATED FOR SAT NIGHT IN
PARTS OF THE CWA AS A WEAK SHORTWAVE APPROACHES FROM THE WEST. AGAIN
VERY LITTLE CHANGE TO HIGH TEMPS WITH 89-92 PROGGED CWA-WIDE.
FINALLY FOR SUNDAY DAYTIME...HAVE KEPT IT VOID OF SLIGHT POPS FOR
NOW...BUT THIS MAY NOT HOLD MUCH LONGER IF THE ECMWF/GFS CONTINUE TO
ADVERTISE THE GENERAL SCENARIO OF THE LOCAL AREA BEING BRUSHED BY A
PASSING SHORTWAVE TRACKING THROUGH THE NORTHERN PLAINS/UPPER MS
VALLEY REGION...WHICH PUSHES A FAIRLY WEAK COLD FRONT THROUGH THE
CWA. KEPT HIGHS UPPER 80S MOST NEB ZONES/NEAR 90 KS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE/AVIATION/LONG TERM...PFANNKUCH
SHORT TERM...HEINLEIN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
625 AM EDT MON AUG 27 2012
.SYNOPSIS...
ANOTHER WARM DAY IS EXPECTED TODAY AS TEMPERATURES WARM AHEAD OF A
STRONG COLD FRONT THAT WILL PASS LATE THIS AFTERNOON INTO THIS
EVENING. AS THIS FEATURE PASSES...SHOWERS AND ISOLATED TO SCATTERED
THUNDERSTORMS WILL MOVE ACROSS MUCH OF CENTRAL NEW YORK AND
NORTHEAST PENNSYLVANIA. FOLLOWING THE FRONTAL PASSAGE...HIGH
PRESSURE AND DRY CONDITIONS WILL RETURN TO THE AREA WITH BELOW
NORMAL TEMPERATURES EXPECTED THROUGH MIDWEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
625 AM UPDATE...
INCREASED POPS TO AN ISOLATED MENTION FOR THE NEXT FEW HRS FROM
THE LOWER WYOMING VLY NORTH THROUGH THE EASTERN SOUTHERN TIER AND
UPPER SUSQUEHANNA BASIN. ACROSS THESE AREAS...WEAK SHOWERS HAVE
FORMED AHEAD OF THE UPPER WAVE LIFTING NORTH FROM THE CENTRAL
MID-ATLANTIC. THE HRRR SHOWS THIS ACTIVITY GRADUALLY DIMINISHING
AS THE LOWER STRATUS DECK BEGINS BREAKING UP WITH ONSET OF DAYTIME
HEATING. LATEST 06Z WRF DELAYS THE ARRIVAL OF THE COLD FRONT AND
ASSOCIATED PRECIP LATER THIS AFTERNOON. BEFORE MAKING ANY
WHOLESALE CHANGES...WILL ALLOW DAYSHIFT TO EVALUATE NEW 12Z
GUIDANCE ONCE IT COMES IN. NO OTHER CHANGES NEEDED AT THIS TIME.
.PREVIOUS NEAR TERM DISCUSSION...
EARLY MORNING 11-3.9U SATELLITE IMAGERY SHOWING AN EXPANDING AREA
OF LOW STRATUS WORKING NORTH INTO CENTRAL NEW YORK EARLY THIS
MORNING. THIS IS OCCURRING AS SOUTHERLY L0W-LEVEL FLOW INCREASES
AHEAD OF THE NOW OPEN WAVE TROUGH ACROSS THE CENTRAL MID-ATLANTIC
REGION. SO FAR REGIONAL RADARS ARE ONLY SHOWING A FEW WEAK RETURNS
DOWN ACROSS SOUTH- CENTRAL PA AS MAIN FORCING REMAINS WELL SOUTH
OF OUR REGION. WITH CLOUDS EXPANDING NORTH IN A WARM AIR ADVECTION
REGIME...EARLY MORNING TEMPS HAVE BEEN VERY SLOW TO FALL WITH
SEVERAL SITES STILL SHOWING VALUES IN THE LOWER 70S AS OF 07Z.
BASED ON NON-IMPRESSIVE RADAR TRENDS...WILL START THE FCST DRY
ACROSS ALL LOCATIONS BEFORE AFOREMENTIONED OPEN WAVE FEATURE
BEGINS WORKING NORTHEAST LATER THIS MORNING. AS THIS OCCURS...A
FEW DEVELOPING SHOWERS FROM THE LOWER WYOMING VLY NORTHEAST
THROUGH THE CATSKILLS AND POCONOS WILL BE POSSIBLE HOWEVER POOR
INSTABILITY WILL KEEP THIS INITIAL ACTIVITY OF THE SHOWER VARIETY.
ACTIVITY ACROSS THE EASTERN ZONES WILL TAKE A SIDE SEAT LATER THIS
AFTERNOON AS A WELL ADVERTISED COLD FRONT BEGINS WORKING THROUGH
THE REGION BETWEEN 18-21Z. UPSTREAM RADAR TRENDS TO THE WEST NOW
SHOWING A FAIRLY WELL DEVELOPED AREA OF SHWRS WORKING EAST THROUGH
EASTERN MI AND WESTERN PORTIONS OF THE SOUTHERN ONTARIO PENINSULA
EARLY THIS MORNING. QUICK LOOK AT VARIOUS BUFKIT FCST SOUNDINGS
SUGGEST INCREASING INSTABILITY GENERATION PRIOR TO FROPA LATER
TODAY WITH MLCAPE VALUES ARE FORECAST TO REACH 500-700 J/KG. THIS
WILL LIKELY BE ENOUGH TO GET SOME CONVECTION GOING AS THE FRONT
MOVES THROUGH AND WILL ADVERTISE AN ISOLATED TO SCATTERED THUNDER
MENTION LATER TODAY INTO TONIGHT. IN TERMS OF SEVERE WX
POTENTIAL...WIND FIELDS ALOFT ACTUALLY LOOK A LITTLE WEAKER THAN
IN PREVIOUS DAYS WITH 0-6KM BULK SHEAR VALUES FORECAST TO REACH 30
KTS AS UPPER JET CORE MOVES OVER THE AREA. THAT SAID...MAIN
LIMITING FACTOR PREVENTING SEVERE WX LATER TODAY AND TONIGHT WILL
BE THE MEAGER INSTABILITY GENERATION AS HIGHLIGHTED ABOVE.
RAIN WILL COME TO AN END FROM WEST TO EAST AFTER 06Z. TOTAL
RAINFALL TOTALS WILL LIKELY RANGE ANYWHERE FROM A QUARTER TO HALF
INCH...HOWEVER HIGHER AMOUNTS WILL BE POSSIBLE UNDER CONVECTIVE
CELLS. ANOTHER TRICKY ASPECT OF THE FCST REVOLVES AROUND HIGH
TEMPS TODAY AS ALL MODELS SHOW A FAIRLY IMPRESSIVE 925 MB THERMAL
RIDGE MOVING OVER THE AREA AHEAD OF THE FRONT. THAT COMBINED WITH
WINDS VEERING TO THE SOUTHWEST AHEAD OF THE BOUNDARY WILL LIKELY
ALLOW TEMPS TO WARM WELL INTO THE LOWER TO MIDDLE 80S ACROSS MUCH
OF CNY...WITH UPPER 70S TO LOWER 80S LIKELY FURTHER SOUTH WHERE
GREATER AMOUNTS OF CLOUD COVER ARE EXPECTED.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
ON TUESDAY...FCST MODELS CONTINUE TO SHOW A SECONDARY COLD FRONT
MOVING THROUGH THE AREA WHICH WILL ALLOW EVEN COOLER AIR TO FILTER
INTO THE EASTERN GREAT LAKES. WITH LIMITED LOW-LEVEL MOISTURE TO
WORK WITH...THE GENERAL CONSENSUS IS THE FRONTAL PASSAGE WILL BE
DRY. COLD AIR ADVECTION IN DEVELOPING NORTHWEST FLOW ALOFT ON
TUESDAY WILL SUPPORT LAKE CLOUD GENERATION ACROSS MUCH OF THE LAKE
PLAIN INTO THE NORTHERN FINGER LAKES AS 850 MB TEMPS DROP TO NEAR
12C. HIGH TEMPS WILL LIKELY ONLY REACH INTO THE LOWER TO MIDDLE
70S.
HIGH PRESSURE WILL THEN SETTLE INTO THE REGION TUE NIGHT BEHIND
THE SECONDARY FRONT. THE ARRIVAL OF THIS FEATURE WILL RESULT IN
FAIR AND COOLER CONDITIONS THROUGH THE CONCLUSION OF THE PERIOD.
OVERNIGHT LOWS EARLY WED MORNING MAY DROP INTO THE UPPER 40S
ACROSS FAVORED VALLEY LOCATIONS WITH HIGH TEMPS ON WED ONLY
WARMING INTO THE UPPER 60S TO LOWER 70S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
330 AM UPDATE...CURRENT EXTENDED FORECAST IN GOOD SHAPE WITH ONLY
MINOR ADJUSTMENTS MADE. MODELS CONTINUE TO SHOW A DRY/WARM STRETCH
OF WEATHER THURSDAY THROUGH SATURDAY, WITH A LARGE UPPER LEVEL
RIDGE ACROSS THE NORTHEAST AND SFC HIGH PRES ALONG THE EAST COAST.
MODEL CONSENSUS AND NHC TRACK FOR ISAAC INDICATES LANDFALL ALONG
THE SOUTHERN LA COAST TUESDAY EVENING. REMNANT MOISTURE FROM THIS
SYSTEM MAY AFFECT AREA SATURDAY NIGHT INTO SUNDAY, BUT THIS FAR
OUT MUCH CAN CHANGE.
PREVIOUS DISC...
EARLY PART OF THE EXTENDED PERIOD FEATURES RISING HEIGHTS AS A
LARGE UPPER LEVEL RIDGE BUILDS IN THE CENTER OF THE U.S. THROUGH
THE OHIO VALLEY...WHICH SHIFTS EASTWARD INTO THE MID-ATLANTIC AND
NORTHEAST STATES BY THE END OF THE WEEK. THIS WILL SPELL A PERIOD
OF DRY WEATHER WITH ABOVE NORMAL TEMPERATURES FOR THIS TIME OF
YEAR...WITH HIGHS NEAR 90 IN LAKE PLAIN AND TYPICAL WARMER SPOTS
FOR FRIDAY AND SATURDAY.
MODEL GUIDANCE CONTINUES A SOMEWHAT SLOWER AND MORE WESTWARD TREND
WITH ISAAC...WITH THE OFFICIAL TRACK FROM NHC NOW MAKING LANDFALL
ALONG THE MS COAST WEDNESDAY MORNING. THIS WILL LIKELY CONTINUE TO
CHANGE WITH UPCOMING MODEL RUNS. THE RESULT FOR US IS MAINLY THAT
ANY MOISTURE TO GET WRAPPED AROUND THE PERIPHERY OF HIGH PRESSURE
SETTLING OFF THE EAST COAST WOULD BE A BIT SLOWER IN ARRIVING...MORE
TWD LATER IN THE WEEKEND.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
STRATUS DECK IS CURRENTLY SPREADING ACROSS THE SOUTHERN TERMINALS
AND THIS WILL PERSIST UNTIL MID MORNING. AT KAVP/KBGM/KELM, LOW
MVFR CIGS WILL OCCUR UNTIL MID MORNING WITH OCCASIONAL IFR CIGS
THROUGH 12Z. AT KITH, MVFR CIGS WILL DEVELOP AFTER 09Z. FOR
KRME/KSYR, CIGS AROUND 4K FT WILL DEVELOP TOWARD DAYBREAK. BY
MIDDAY, CU FIELD WILL SCATTERED OUT WITH MAINLY MID LEVEL CLOUDS.
COLD FRONT WILL CROSS AREA OVERNIGHT BRINGING MVFR SHOWERS. THIS
ACTIVITY WILL BEGIN AROUND 22Z OVER WESTERN TAF LOCATIONS AND
AROUND 02Z AT KAVP.
LIGHT AND VARIABLE WINDS EARLY THIS MORNING BECOMING S/SW BY MID
MORNING AROUND 10 KNOTS THEN SOUTHWEST THIS EVENING.
OUTLOOK...
TUE THRU FRIDAY...MAINLY VFR...LATE NGT VLY FOG PSBL.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...CMG
SHORT TERM...CMG
LONG TERM...JML/RRM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS RALEIGH NC
324 PM EDT MON AUG 27 2012
.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN OVER THE AREA TONIGHT. AS TROPICAL CYCLONE
ISAAC APPROACHES THE NORTHERN GULF COAST ON TUESDAY...THE DEEP
TROPICAL MOISTURE PLUME WILL SPREAD NORTHWARD INTO THE CAROLIN
AS...WHERE IT WILL INTERACT WITH A COLD FRONT APPROACHING FROM THE
NORTHWEST LATE TUESDAY OR TUESDAY NIGHT. THE SLOW MOVING COLD
FRONT COULD POTENTIALLY STALL ACROSS THE AREA ON
WEDNESDAY...BEFORE FINALLY SHIFTING SOUTH OF THE AREA ON THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 PM MONDAY...
LATEST SURFACE ANALYSIS SHOWS TROPICAL STORM ISAAC IN THE
EAST-CENTRAL GULF OF MEXICO. A SOUTHEASTERLY LOW LEVEL FLOW OFF THE
ATLANTIC ASSOCIATED WITH ISAAC COMBINED WITH A NARROW RIDGE OF HIGH
PRESSURE EXTENDING SOUTHWESTWARD ACROSS THE WESTERN PIEDMONT OF VA
AND NC HAS RESULTED IN THE DEVELOPMENT OF AN INLAND PENETRATING
COASTAL FRONT. THE FRONT HAS BEEN ENHANCED BY SEA BREEZE BOUNDARIES
ACROSS SOUTHERN COASTAL AREAS AND WITH CONVECTIVE OUTFLOW ACROSS THE
CENTRAL COASTAL AREA. AN AREA OF SHOWERS WITH A FEW EMBEDDED
THUNDERSTORMS IS ASSOCIATED WITH THE BOUNDARY...ELSEWHERE FAIR
WEATHER WITH SCT-BKN CUMULUS IS WIDESPREAD ACROSS THE REMAINDER OF
CENTRAL NORTH CAROLINA.
THE CONVECTION IS EXPECTED TO CONTINUE ADVANCING NORTHWEST THIS
AFTERNOON AND EARLY EVENING. AIDED BY A WEAKLY UNSTABLE AIR MASS
WITH MLCAPE VALUES RANGING FROM 500-1000 J/KG AND ONLY MODEST MID
LEVEL LAPSE RATES. THE CONVECTION IS EXPECTED TO DECREASE IN
COVERAGE AND INTENSITY AS IT MOVES FURTHER INLAND TOWARD THE SFC
RIDGE AND INTO A REGION OF DEW POINTS IN THE MID/UPPER 60S AND
RESULTANT MLCAPE VALUES OF LESS THAN 500 J/KG. THIS TREND IS
SUPPORTED BY RECENT HRRR RUNS WHICH HAS HANDLED THIS WELL. THE
PRECIPITATION MAY LINGER INTO THE EVENING HOURS...MAINLY ACROSS THE
SOUTHERN COASTAL PLAIN/SANDHILLS/SOUTHERN PIEDMONT BEFORE FAIR
WEATHER ARRIVES ACROSS CENTRAL LATE THIS EVENING AND OVERNIGHT.
ANOTHER ROUND OF STRATUS AND FOG IS EXPECTED TO DEVELOP LATE
TONIGHT. WITH A SUB-TROPICAL AIR MASS IN PLACE ACROSS THE
REGION...LOWS TONIGHT SHOULD FALL INTO THE 67-72 RANGE FROM WEST TO
EAST. -BLAES
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
AS OF 315 PM MONDAY...
A NORTHERN STREAM SHORT WAVE AND THE ASSOCIATED COLD FRONT WILL BE
MOVING ACROSS THE CENTRAL APPALACHIANS EARLY TUESDAY. THE
SOUTHEASTERLY LOW LEVEL FLOW BECOMES MORE SOUTHWESTERLY AHEAD OF THE
FRONT. AN AREA OF CONVECTION OFF THE FL COAST ASSOCIATED WITH A LOW
LEVEL PERTURBATION WILL ADVANCE NORTH AND NORTHEAST AND MOVE ACROSS
EASTERN AND SOUTHEASTERN SC/NC. RECENT GUIDANCE SUGGESTS THAT THIS
FEATURE WILL LIKELY NOT INTERACT WITH THE FRONT A GREAT DEAL. STILL
THE PERTURBATION IN A REGION OF HIGH PRECIPITABLE WATER THAT WILL BE
ENHANCED BY THE ENTRANCE REGION OF A JET ALOFT WILL PRODUCE AN AREA
OF SHOWERS AND THUNDERSTORMS THAT MOVES ACROSS THE
SOUTHERN/SOUTHEASTERN PORTION OF THE CWA LATE TUESDAY MORNING AND
CONTINUES INTO THE EVENING HOURS. HAVE OPTED TO HOLD OFF ON
INCLUDING LIKELY POPS GIVEN RECENT GUIDANCE FROM CONVECTION ALLOWING
MODELS. AT THIS POINT QPF VALUES ARE EXPECTED TO BE LIMITED AND
GENERALLY RANGE AROUND A HALF INCH WITH A FEW LOCATIONS RECEIVING UP
TO AN INCH. THE SEVERE THREAT AT THIS TIME APPEARS SOMEWHAT LIMITED
WITH MODEST DEEP LAYER SHEAR OF AROUND 20KTS AND A WEAKLY UNSTABLE
AIRMASS WITH MLCAPE VALUES OF 500-1000 J/KG. LOCALIZED HEAVY RAIN IS
THE LARGER THREAT AT THIS TIME.
THE COLD FRONT IS EXPECTED TO SLOWLY DROP SOUTHWARD REACHING THE
SOUTHERN COASTAL PLAIN BY DAYBREAK WEDNESDAY. WITH THE FRONT IN THE
VICINITY AND A DEEP SOUTHERLY FLOW...WIDESPREAD CLOUDINESS SHOULD
DEVELOP AND PERSIST THROUGH THE PERIOD. HIGH TEMPERATURES WILL RANGE
IN THE UPPER 80S ACROSS THE NORTHEAST TO MID 80S ELSEWHERE. LOWS ON
TUESDAY NIGHT WILL RANGE IN THE UPPER 60S TO LOWER 70S. -BLAES
A COLD FRONT WILL BE PUSHING SOUTH THROUGH THE CWA BY 12Z WEDNESDAY
MORNING. THE ASSOCIATED MID LEVEL SHEAR AXIS WILL ALSO PUSH SOUTH
INTO THE AREA...THOUGH MODELS ARE WEAKER WITH THIS FEATURE WITH A
WESTWARD SHIFT IN THE MODEL/NHC TRACK OF TS ISAAC AND LESS
INTERACTION WITH THE SHORTWAVE CROSSING NEW ENGLAND. MODELS SHOW
THE 85OMB TROUGH AXIS DRAPED ACROSS THE AREA JUST NORTH OF THE NC/SC
BORDER WEDNESDAY...WITH PW IN EXCESS OF 2 INCHES JUST TO THE
SOUTH. THE FRONTAL ZONE WILL BE SLOWING AT THAT POINT...SO THE
DELINEATION BETWEEN WIDESPREAD SHOWERS AND DRY CONDITIONS WILL BE
NARROW...ALTHOUGH THE RIGHT ENTRANCE REGION OF A WESTWARD BUILDING
UPPER JET WILL PROVIDE BROAD LIFT TO SUPPORT AT LEAST CHANCE POPS
AREAWIDE. THERE IS THE POTENTIAL HIGHS TO BE WARMER NORTH THAN
SOUTH DEPENDING ON PRECIP COVERAGE AND POTENTIAL BREAKS IN OVERCAST
SKIES...WITH MID 80S POSSIBLE NORTH AND LOWER 80S MORE LIKELY SOUTH.
INSTABILITY SHOULD BE LIMITED BY CLOUD COVER AND WEAK MID LEVEL WIND
FIELDS SHOULD LIMIT AN SEVERE THREAT WEDNESDAY AFTERNOON.
HOWEVER...SHOWERS AND STORMS WILL HAVE HEAVY RAIN WITH A STORM
MOTION SOMEWHAT PARALLEL TO THE FRONT...SO A FLOODING THREAT MAY
EXIST.
THE SURFACE FRONT AND LOW LEVEL TROUGH SHOULD SLIP FURTHER SOUTH
WEDNESDAY NIGHT...AND WITH IT THE FOCUS FOR BETTER PRECIP COVERAGE.
HOWEVER...WE WILL MAINTAIN A CHANCE POPS FOR THE SOUTHERN PIEDMONT
AND SANDHILLS INTO THE OVERNIGHT HOURS AND EARLY
THURSDAY....DECREASING FROM NORTH TO SOUTH ON THURSDAY. LOWS
RANGING FROM THE MID 60S NORTHEAST TO UPPER 60S SOUTHWEST. HIGHS
THURSDAY IN THE MID 80S. -SMITH
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 315 PM MONDAY...
WITH MODELS CONTINUING TO SHIFT SLIGHTLY WESTWARD WITH THE TRACK OF
TS ISAAC...THERE IS STILL QUITE A BIT OF UNCERTAINTY REGARDING THE
EVOLUTION AND TRACK OF ITS REMNANTS...AND HOW THAT WILL PLAY OUT
OVER THE EASTERN US DURING THE UPCOMING WEEKEND INTO EARLY NEXT
WEEK. IN GENERAL...THE REMNANTS OF ISAAC ARE FORECAST TO MOVE
NORTH THROUGH THE CENTRAL PLAINS...AROUND THE MID LEVEL RIDGE AS
THE RIDGE ITSELF BUILDS EAST THE OH VALLEY REGION. MODELS SHOW THE
MID LEVEL RIDGE SHIFTING OVER THE VIRGINIAS/CAROLINAS BY FRIDAY
AND SATURDAY...WITH THE BETTER MOISTURE PLUME SURGING NORTH
BETWEEN THE MS RIVER AND TN VALLEY REGIONS. THIS WOULD GREATLY
REDUCE THE POTENTIAL FOR SHOWERS AND STORMS OVER CENTRAL NC FRIDAY
AND SATURDAY...WITH MOST ACTIVITY FROM THE MOUNTAINS WESTWARD.
CLOUD COVER WILL ALSO BE GREATEST OVER THE WEST....AND HIGHS WILL
ACCORDING VARY FROM SOUTHWEST TO NORTHEAST. UNDER A STRENGTHENING
MID LEVEL RIDGE...MODELS INDICATE 850MB TEMPS APPROACHING 18-19C BY
SATURDAY AND SUNDAY...WHICH BY ITSELF WOULD SUGGEST HIGHS IN THE
MID 90S. THERE IS LIKELY TO BE QUITE A BIT OF CIRRUS EAST OF THE
REMNANTS OF ISAAC...SO HIGHS IN THE UPPER 80S AND LOWER 90S SEEM
MORE REASONABLE AT THIS POINT.
MODELS THEN DIVERGE A BIT BEYOND 00Z SUNDAY REGARDING THE REMNANT
MID LEVEL PV FROM ISAAC...WHICH THE 12Z GFS NOW SHOWING A DEEPER
AN STRONGER MID/UPPER LOW SINKING INTO THE TN VALLEY SUNDAY. THE
12Z ECMWF NOW SHOWS SIGNS OF THE CIRCULATION EVENTUALLY DRIFTING
SOUTHEAST TOWARD THE TN VALLEY AND SOUTHEAST US...WHICH IS
REMARKABLY DIFFERENT THAT ITS PREVIOUS RUN. WE WILL CONTINUE TO
SHOW AN INCREASE IN POPS INTO EARLY NEXT WEEK...ALTHOUGH
CONFIDENCE IS TOO LOW TO INCREASE THE CURRENT SLIGHT CHANCE TO LOW
CHANCE WORDING.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
AS OF 210 PM MONDAY...
VFR CONDITIONS ARE PREDOMINATE ACROSS CENTRAL NC THIS AFTERNOON WITH
SCT-BKN CUMULUS WITH BASES OF 3-5KFT. A WESTWARD MOVING COASTAL
FRONT ENHANCED BY SEA BREEZE AND CONVECTIVE BOUNDARIES WILL MOVE
ACROSS THE COASTAL PLAIN THIS AFTERNOON AND COULD BRING A SHORT
PERIOD OF MVFR CIGS/VSBYS IN A RAIN SHOWER. FAIR WEATHER WITH MAINLY
SCT LOW/MID LEVEL CLOUDS IS EXPECTED ELSEWHERE THIS AFTERNOON. FAIR
WEATHER IS EXPECTED EVERYWHERE THIS EVENING AND DURING THE EARLY
OVERNIGHT HOURS BEFORE AREAS OF MORNING STRATUS AND SOME FOG DEVELOP
TOWARD DAYBREAK. HAVE HIGHLIGHTED POTENTIAL FOR A BRIEF PERIOD OF
IFR/LIFR CONDITIONS WITH FOG/STRATUS AT KRWI TUESDAY MORNING WITH
MAINLY MVFR CONDITIONS EXPECTED ELSEWHERE. BKN CLOUDINESS WITH BASES
RANGING FROM 3KFT EAST TO 5KFT WEST ARE EXPECTED ON TUESDAY.
THE WEATHER DURING THE EXTENDED RANGE WILL LARGELY DEPEND ON THE
EVOLUTION OF TROPICAL CYCLONE ISAAC AND A COLD FRONT THAT WILL MOVE
ACROSS THE AREA LATE TUESDAY AND WEDNESDAY. THIS SURFACE BOUNDARY IS
PREDICTED TO STALL OVER THE CAROLINAS. AT THIS TIME... A PERIOD OF
ADVERSE AVIATION CONDITIONS MAY IMPACT THE AREA FROM LATE TUESDAY
THROUGH THURSDAY WITH SUB VFR CEILINGS AS WELL AS SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS. MORE WIDELY SCATTERED SHOWERS
WITH A REDUCED POTENTIAL FOR ADVERSE IMPACT IS EXPECTED ON FRIDAY
AND SATURDAY. -BLAES
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BLAES
SHORT TERM...BLAES/SMITH
LONG TERM...SMITH
AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
240 PM EDT MON AUG 27 2012
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER THE AREA TODAY...BEFORE WEAKENING
TONIGHT. AS TROPICAL CYCLONE ISAAC APPROACHES THE NORTHERN GULF
COAST ON TUESDAY...THE DEEP TROPICAL MOISTURE PLUME WILL SPREAD
NORTHWARD INTO THE CAROLINAS...WHERE IT WILL INTERACT WITH A COLD
FRONT APPROACHING FROM THE NORTHWEST LATE TUESDAY OR TUESDAY
NIGHT. THE SLOW MOVING COLD FRONT COULD POTENTIALLY STALL ACROSS
THE AREA ON WEDNESDAY...BEFORE FINALLY SHIFTING SOUTH OF THE AREA
ON THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 PM EDT...
LATEST SURFACE ANALYSIS SHOWS TROPICAL STORM ISAAC IN THE
EAST-CENTRAL GULF OF MEXICO. A SOUTHEASTERLY LOW LEVEL FLOW OFF THE
ATLANTIC ASSOCIATED WITH ISAAC COMBINED WITH A NARROW RIDGE OF HIGH
PRESSURE EXTENDING SOUTHWESTWARD ACROSS THE WESTERN PIEDMONT OF VA
AND NC HAS RESULTED IN THE DEVELOPMENT OF AN INLAND PENETRATING
COASTAL FRONT. THE FRONT HAS BEEN ENHANCED BY SEA BREEZE BOUNDARIES
ACROSS SOUTHERN COASTAL AREAS AND WITH CONVECTIVE OUTFLOW ACROSS THE
CENTRAL COASTAL AREA. AN AREA OF SHOWERS WITH A FEW EMBEDDED
THUNDERSTORMS IS ASSOCIATED WITH THE BOUNDARY...ELSEWHERE FAIR
WEATHER WITH SCT-BKN CUMULUS IS WIDESPREAD ACROSS THE REMAINDER OF
CENTRAL NORTH CAROLINA.
THE CONVECTION IS EXPECTED TO CONTINUE ADVANCING NORTHWEST THIS
AFTERNOON AND EARLY EVENING. AIDED BY A WEAKLY UNSTABLE AIR MASS
WITH MLCAPE VALUES RANGING FROM 500-1000 J/KG AND ONLY MODEST MID
LEVEL LAPSE RATES. THE CONVECTION IS EXPECTED TO DECREASE IN
COVERAGE AND INTENSITY AS IT MOVES FURTHER INLAND TOWARD THE SFC
RIDGE AND INTO A REGION OF DEW POINTS IN THE MID/UPPER 60S AND
RESULTANT MLCAPE VALUES OF LESS THAN 500 J/KG. THIS TREND IS
SUPPORTED BY RECENT HRRR RUNS WHICH HAS HANDLED THIS WELL. THE
PRECIPITATION MAY LINGER INTO THE EVENING HOURS...MAINLY ACROSS THE
SOUTHERN COASTAL PLAIN/SANDHILLS/SOUTHERN PIEDMONT BEFORE FAIR
WEATHER ARRIVES ACROSS CENTRAL LATE THIS EVENING AND OVERNIGHT.
ANOTHER ROUND OF STRATUS AND FOG IS EXPECTED TO DEVELOP LATE
TONIGHT. WITH A SUB-TROPICAL AIR MASS IN PLACE ACROSS THE
REGION...LOWS TONIGHT SHOULD FALL INTO THE 67-72 RANGE FROM WEST TO
EAST. -BLAES
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM MONDAY...
AS AFOREMENTIONED NORTHERN STREAM TROUGH ADVANCES EAST THROUGH THE
NORTHEAST UNITED STATES ON TUESDAY...TRAILING SURFACE COLD FRONT
WILL MOVE SLOWLY EAST SOUTHEAST INTO THE AREA TUESDAY AFTERNOON
AND TUESDAY EVENING... WHERE MODELS SUGGEST IT COULD STALL THROUGH
THURSDAY. WHILE MOISTURE IS CURRENTLY LIMITED WITH THE COLD
FRONT...THE INTERACTION OF THE FRONT WITH THE NORTHERN PERIPHERY
OF THE EXPANSIVE TROPICAL MOISTURE PLUME ASSOCIATED WITH THE LARGE
WIND FIELD OF ISAAC COULD RESULT IN THE POTENTIAL FOR HEAVY RAIN
ACROSS THE CAROLINAS LATE TUESDAY AFTERNOON AND TUESDAY NIGHT...
ESPECIALLY IN THE UPSLOPE AREAS ALONG THE EASTERN SLOPES AND
ACROSS SOUTHERN PORTIONS OF THE STATE WHERE PRECIPITABLE WATERS
ARE EXPECTED TO BE ABOVE TWO INCHES.
IT REMAINS IMPORTANT TO NOTE THAT THIS HEAVY RAIN POTENTIAL WILL
ULTIMATELY DEPEND ON THE TRACK OF ISAAC...WITH ANY WESTWARD DEVIATION
TO THE FORECAST TRACK REDUCING THE HEAVY RAINFALL THREAT. SO AS YOU
CAN SEE...THERE IS STILL LOTS OF UNCERTAINTY AT THIS TIME.. AS SUCH
WILL KEEP POPS IN 40 TO 50 PERCENT CHANCE CATEGORIES. AS FAR AS A
SEVERE THREAT...THERE ARE QUESTIONS ABOUT HOW EXTENSIVE CLOUD COVER
WILL BE DURING THE DAY ON TUESDAY AND HOW IT MAY LIMIT
DESTABILIZATION...BUT SOME OF THE MODELS STILL DEVELOP MODERATE
INSTABILITY ACROSS THE SOUTH/SOUTHEAST. WINDS ALOFT ARE FAIRLY
WEAK...15 TO 20 KNOTS...SO DO NOT EXPECT MUCH MORE THAN AN ISOLATED
SEVERE THREAT TUESDAY AFTERNOON.
HIGHS TUESDAY GENERALLY IN THE LOWER TO MID 80S. OVERNIGHT LOWS
IN THE UPPER 60S ACROSS THE NORTH TO LOWER TO MID 70S SOUTH.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...
THERE IS STILL A GREAT DEAL OF UNCERTAINTY FOR THE LONG TERM PERIOD
AS MUCH OF OUR WEATHER WILL ULTIMATELY DEPEND ON THE TRACK OF ISAAC
AND ITS EVENTUAL REMNANTS. THE OFFICIAL NATIONAL HURRICANE CENTER
TRACK HAS ISAAC MAKING LANDFALL SOUTH OF NEW ORLEANS LATE TUESDAY.
HOWEVER...MODELS CONTINUE TO STRUGGLE WITH RESPECT TO THE TRACK OF
ISAAC AND ITS EVENTUAL REMNANTS AS IT WILL BE DEPENDENT HOW IT
INTERACTS WITH AN UPPER LEVEL TROUGH THAT WILL BE APPROACHING THE
EAST COAST.
WEDNESDAY...THIS UPPER LEVEL TROUGH AND AN ASSOCIATED SURFACE
FRONT WILL PROVIDE A FOCUS FOR PRECIPITATION ACROSS CENTRAL NORTH
CAROLINA. MODELS DO AGREE ON A PLUME OF DEEP TROPICAL MOISTURE
BEING OVER THE REGION DURING THIS TIME FRAME...WITH PRECIPITABLE
WATER VALUES FORECAST TO EXCEED 2 INCHES (ESPECIALLY ACROSS THE
SOUTHEASTERN PORTION OF THE FORECAST AREA). AS A RESULT...WILL
MAINTAIN HIGH END CHANCE POPS...HIGHEST ACROSS THE SOUTHEASTERN
CWA. BEYOND WEDNESDAY...FORECAST UNCERTAINTY INCREASES AS OUR RAIN
CHANCES WILL HINGE ON THE TRACK OF THE REMNANTS OF ISAAC. THE GFS
CONTINUES TO BE FURTHER WEST...AS THE AFOREMENTIONED UPPER LEVEL
TROUGH MOVES OFFSHORE FASTER AND THEREFORE THERE IS LITTLE
INTERACTION BETWEEN IT AND ISAAC. AS A RESULT...THE REMNANT LOW
TRACKS WEST OF THE MS RIVER VALLEY AND EVENTUALLY EASTWARD LATE
NEXT WEEKEND AS IT IS PICKED UP BY THE NEXT TROUGH. THIS SOLUTION
WOULD LEAVE CENTRAL NORTH CAROLINA FAIRLY DRY FOR THE LATTER HALF
OF THE PERIOD...AS A MID LEVEL HIGH BUILDS OVER THE REGION.
HOWEVER...THE ECMWF IS SLIGHTLY SLOWER WITH THE PROGRESSION OF THE
UPPER LEVEL TROUGH..WHICH RESULTS IN INTERACTION BETWEEN ISAAC AND
THE UPPER LEVEL TROUGH...THEREFORE PULLING THE REMNANT LOW MORE
NORTHWARD AND TRACKS IT SOMEWHERE BETWEEN THE MISSISSIPPI VALLEY
AND THE APPALACHIANS (ALTHOUGH IT HAS ALSO BEEN TRENDING WESTWARD
DURING THE PAST SEVERAL RUNS). THIS SOLUTION WOULD RESULT IN A
LONGER PERIOD OF RAIN CHANCES FOR THE REGION. DUE TO THE
UNCERTAINTY...WILL MAINTAIN FORECAST CONTINUITY AND WILL SHOW A
GRADUAL TREND OF DECREASING POPS AFTER WEDNESDAY...BUT WILL KEEP
AT LEAST A SLIGHT CHANCE IN FOR THE ENTIRE PERIOD. AFTER HIGHS
ONLY NEAR 80 DEGREES ON WEDNESDAY... MAXIMUM TEMPERATURES WILL
TREND UPWARDS THROUGH THE REMAINDER OF THE PERIOD...WITH UPPER 80S
EXPECTED BY THE END OF NEXT WEEKEND. OVERNIGHT LOWS WILL GENERALLY
BE IN THE UPPER 60S TO LOWER 70S THROUGHOUT THE PERIOD.
&&
.AVIATION /18Z MONDAY THROUGH FRIDAY/...
AS OF 210 PM MONDAY...
VFR CONDITIONS ARE PREDOMINATE ACROSS CENTRAL NC THIS AFTERNOON WITH
SCT-BKN CUMULUS WITH BASES OF 3-5KFT. A WESTWARD MOVING COASTAL
FRONT ENHANCED BY SEA BREEZE AND CONVECTIVE BOUNDARIES WILL MOVE
ACROSS THE COASTAL PLAIN THIS AFTERNOON AND COULD BRING A SHORT
PERIOD OF MVFR CIGS/VSBYS IN A RAIN SHOWER. FAIR WEATHER WITH MAINLY
SCT LOW/MID LEVEL CLOUDS IS EXPECTED ELSEWHERE THIS AFTERNOON. FAIR
WEATHER IS EXPECTED EVERYWHERE THIS EVENING AND DURING THE EARLY
OVERNIGHT HOURS BEFORE AREAS OF MORNING STRATUS AND SOME FOG DEVELOP
TOWARD DAYBREAK. HAVE HIGHLIGHTED POTENTIAL FOR A BRIEF PERIOD OF
IFR/LIFR CONDITIONS WITH FOG/STRATUS AT KRWI TUESDAY MORNING WITH
MAINLY MVFR CONDITIONS EXPECTED ELSEWHERE. BKN CLOUDINESS WITH BASES
RANGING FROM 3KFT EAST TO 5KFT WEST ARE EXPECTED ON TUESDAY.
THE WEATHER DURING THE EXTENDED RANGE WILL LARGELY DEPEND ON THE
EVOLUTION OF TROPICAL CYCLONE ISAAC AND A COLD FRONT THAT WILL MOVE
ACROSS THE AREA LATE TUESDAY AND WEDNESDAY. THIS SURFACE BOUNDARY IS
PREDICTED TO STALL OVER THE CAROLINAS. AT THIS TIME... A PERIOD OF
ADVERSE AVIATION CONDITIONS MAY IMPACT THE AREA FROM LATE TUESDAY
THROUGH THURSDAY WITH SUB VFR CEILINGS AS WELL AS SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS. MORE WIDELY SCATTERED SHOWERS
WITH A REDUCED POTENTIAL FOR ADVERSE IMPACT IS EXPECTED ON FRIDAY
AND SATURDAY. -BLAES
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...BLAES
SHORT TERM...CBL
LONG TERM...KRR
AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
340 PM EDT MON AUG 27 2012
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER THE AREA TODAY...BEFORE WEAKENING
TONIGHT. AS TROPICAL CYCLONE ISAAC APPROACHES THE NORTHERN GULF
COAST ON TUESDAY...THE DEEP TROPICAL MOISTURE PLUME WILL SPREAD
NORTHWARD INTO THE CAROLINAS...WHERE IT WILL INTERACT WITH A COLD
FRONT APPROACHING FROM THE NORTHWEST LATE TUESDAY OR TUESDAY
NIGHT. THE SLOW MOVING COLD FRONT COULD POTENTIALLY STALL ACROSS
THE AREA ON WEDNESDAY...BEFORE FINALLY SHIFTING SOUTH OF THE AREA
ON THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 340 PM EDT...
LATEST SURFACE ANALYSIS SHOWS TROPICAL STORM ISAAC IN THE
EAST-CENTRAL GULF OF MEXICO. A SOUTHEASTERLY LOW LEVEL FLOW OFF THE
ATLANTIC ASSOCIATED WITH ISAAC COMBINED WITH A NARROW RIDGE OF HIGH
PRESSURE EXTENDING SOUTHWESTWARD ACROSS THE WESTERN PIEDMONT OF VA
AND NC HAS RESULTED IN THE DEVELOPMENT OF AN INLAND PENETRATING
COASTAL FRONT. THE FRONT HAS BEEN ENHANCED BY SEA BREEZE BOUNDARIES
ACROSS SOUTHERN COASTAL AREAS AND WITH CONVECTIVE OUTFLOW ACROSS THE
CENTRAL COASTAL AREA. AN AREA OF SHOWERS WITH A FEW EMBEDDED
THUNDERSTORMS IS ASSOCIATED WITH THE BOUNDARY...ELSEWHERE FAIR
WEATHER WITH SCT-BKN CUMULUS IS WIDESPREAD ACROSS THE REMAINDER OF
CENTRAL NORTH CAROLINA.
THE CONVECTION IS EXPECTED TO CONTINUE ADVANCING NORTHWEST THIS
AFTERNOON AND EARLY EVENING. AIDED BY A WEAKLY UNSTABLE AIR MASS
WITH MLCAPE VALUES RANGING FROM 500-1000 J/KG AND ONLY MODEST MID
LEVEL LAPSE RATES. THE CONVECTION IS EXPECTED TO DECREASE IN
COVERAGE AND INTENSITY AS IT MOVES FURTHER INLAND TOWARD THE SFC
RIDGE AND INTO A REGION OF DEW POINTS IN THE MID/UPPER 60S AND
RESULTANT MLCAPE VALUES OF LESS THAN 500 J/KG. THIS TREND IS
SUPPORTED BY RECENT HRRR RUNS WHICH HAS HANDLED THIS WELL. THE
PRECIPITATION MAY LINGER INTO THE EVENING HOURS...MAINLY ACROSS THE
SOUTHERN COASTAL PLAIN/SANDHILLS/SOUTHERN PIEDMONT BEFORE FAIR
WEATHER ARRIVES ACROSS CENTRAL LATE THIS EVENING AND OVERNIGHT.
ANOTHER ROUND OF STRATUS AND FOG IS EXPECTED TO DEVELOP LATE
TONIGHT. WITH A SUB-TROPICAL AIR MASS IN PLACE ACROSS THE
REGION...LOWS TONIGHT SHOULD FALL INTO THE 67-72 RANGE FROM WEST TO
EAST. -BLAES
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM MONDAY...
AS AFOREMENTIONED NORTHERN STREAM TROUGH ADVANCES EAST THROUGH THE
NORTHEAST UNITED STATES ON TUESDAY...TRAILING SURFACE COLD FRONT
WILL MOVE SLOWLY EAST SOUTHEAST INTO THE AREA TUESDAY AFTERNOON
AND TUESDAY EVENING... WHERE MODELS SUGGEST IT COULD STALL THROUGH
THURSDAY. WHILE MOISTURE IS CURRENTLY LIMITED WITH THE COLD
FRONT...THE INTERACTION OF THE FRONT WITH THE NORTHERN PERIPHERY
OF THE EXPANSIVE TROPICAL MOISTURE PLUME ASSOCIATED WITH THE LARGE
WIND FIELD OF ISAAC COULD RESULT IN THE POTENTIAL FOR HEAVY RAIN
ACROSS THE CAROLINAS LATE TUESDAY AFTERNOON AND TUESDAY NIGHT...
ESPECIALLY IN THE UPSLOPE AREAS ALONG THE EASTERN SLOPES AND
ACROSS SOUTHERN PORTIONS OF THE STATE WHERE PRECIPITABLE WATERS
ARE EXPECTED TO BE ABOVE TWO INCHES.
IT REMAINS IMPORTANT TO NOTE THAT THIS HEAVY RAIN POTENTIAL WILL
ULTIMATELY DEPEND ON THE TRACK OF ISAAC...WITH ANY WESTWARD DEVIATION
TO THE FORECAST TRACK REDUCING THE HEAVY RAINFALL THREAT. SO AS YOU
CAN SEE...THERE IS STILL LOTS OF UNCERTAINTY AT THIS TIME.. AS SUCH
WILL KEEP POPS IN 40 TO 50 PERCENT CHANCE CATEGORIES. AS FAR AS A
SEVERE THREAT...THERE ARE QUESTIONS ABOUT HOW EXTENSIVE CLOUD COVER
WILL BE DURING THE DAY ON TUESDAY AND HOW IT MAY LIMIT
DESTABILIZATION...BUT SOME OF THE MODELS STILL DEVELOP MODERATE
INSTABILITY ACROSS THE SOUTH/SOUTHEAST. WINDS ALOFT ARE FAIRLY
WEAK...15 TO 20 KNOTS...SO DO NOT EXPECT MUCH MORE THAN AN ISOLATED
SEVERE THREAT TUESDAY AFTERNOON.
HIGHS TUESDAY GENERALLY IN THE LOWER TO MID 80S. OVERNIGHT LOWS
IN THE UPPER 60S ACROSS THE NORTH TO LOWER TO MID 70S SOUTH.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...
THERE IS STILL A GREAT DEAL OF UNCERTAINTY FOR THE LONG TERM PERIOD
AS MUCH OF OUR WEATHER WILL ULTIMATELY DEPEND ON THE TRACK OF ISAAC
AND ITS EVENTUAL REMNANTS. THE OFFICIAL NATIONAL HURRICANE CENTER
TRACK HAS ISAAC MAKING LANDFALL SOUTH OF NEW ORLEANS LATE TUESDAY.
HOWEVER...MODELS CONTINUE TO STRUGGLE WITH RESPECT TO THE TRACK OF
ISAAC AND ITS EVENTUAL REMNANTS AS IT WILL BE DEPENDENT HOW IT
INTERACTS WITH AN UPPER LEVEL TROUGH THAT WILL BE APPROACHING THE
EAST COAST.
WEDNESDAY...THIS UPPER LEVEL TROUGH AND AN ASSOCIATED SURFACE
FRONT WILL PROVIDE A FOCUS FOR PRECIPITATION ACROSS CENTRAL NORTH
CAROLINA. MODELS DO AGREE ON A PLUME OF DEEP TROPICAL MOISTURE
BEING OVER THE REGION DURING THIS TIME FRAME...WITH PRECIPITABLE
WATER VALUES FORECAST TO EXCEED 2 INCHES (ESPECIALLY ACROSS THE
SOUTHEASTERN PORTION OF THE FORECAST AREA). AS A RESULT...WILL
MAINTAIN HIGH END CHANCE POPS...HIGHEST ACROSS THE SOUTHEASTERN
CWA. BEYOND WEDNESDAY...FORECAST UNCERTAINTY INCREASES AS OUR RAIN
CHANCES WILL HINGE ON THE TRACK OF THE REMNANTS OF ISAAC. THE GFS
CONTINUES TO BE FURTHER WEST...AS THE AFOREMENTIONED UPPER LEVEL
TROUGH MOVES OFFSHORE FASTER AND THEREFORE THERE IS LITTLE
INTERACTION BETWEEN IT AND ISAAC. AS A RESULT...THE REMNANT LOW
TRACKS WEST OF THE MS RIVER VALLEY AND EVENTUALLY EASTWARD LATE
NEXT WEEKEND AS IT IS PICKED UP BY THE NEXT TROUGH. THIS SOLUTION
WOULD LEAVE CENTRAL NORTH CAROLINA FAIRLY DRY FOR THE LATTER HALF
OF THE PERIOD...AS A MID LEVEL HIGH BUILDS OVER THE REGION.
HOWEVER...THE ECMWF IS SLIGHTLY SLOWER WITH THE PROGRESSION OF THE
UPPER LEVEL TROUGH..WHICH RESULTS IN INTERACTION BETWEEN ISAAC AND
THE UPPER LEVEL TROUGH...THEREFORE PULLING THE REMNANT LOW MORE
NORTHWARD AND TRACKS IT SOMEWHERE BETWEEN THE MISSISSIPPI VALLEY
AND THE APPALACHIANS (ALTHOUGH IT HAS ALSO BEEN TRENDING WESTWARD
DURING THE PAST SEVERAL RUNS). THIS SOLUTION WOULD RESULT IN A
LONGER PERIOD OF RAIN CHANCES FOR THE REGION. DUE TO THE
UNCERTAINTY...WILL MAINTAIN FORECAST CONTINUITY AND WILL SHOW A
GRADUAL TREND OF DECREASING POPS AFTER WEDNESDAY...BUT WILL KEEP
AT LEAST A SLIGHT CHANCE IN FOR THE ENTIRE PERIOD. AFTER HIGHS
ONLY NEAR 80 DEGREES ON WEDNESDAY... MAXIMUM TEMPERATURES WILL
TREND UPWARDS THROUGH THE REMAINDER OF THE PERIOD...WITH UPPER 80S
EXPECTED BY THE END OF NEXT WEEKEND. OVERNIGHT LOWS WILL GENERALLY
BE IN THE UPPER 60S TO LOWER 70S THROUGHOUT THE PERIOD.
&&
.AVIATION /18Z MONDAY THROUGH FRIDAY/...
AS OF 210 PM MONDAY...
VFR CONDITIONS ARE PREDOMINATE ACROSS CENTRAL NC THIS AFTERNOON WITH
SCT-BKN CUMULUS WITH BASES OF 3-5KFT. A WESTWARD MOVING COASTAL
FRONT ENHANCED BY SEA BREEZE AND CONVECTIVE BOUNDARIES WILL MOVE
ACROSS THE COASTAL PLAIN THIS AFTERNOON AND COULD BRING A SHORT
PERIOD OF MVFR CIGS/VSBYS IN A RAIN SHOWER. FAIR WEATHER WITH MAINLY
SCT LOW/MID LEVEL CLOUDS IS EXPECTED ELSEWHERE THIS AFTERNOON. FAIR
WEATHER IS EXPECTED EVERYWHERE THIS EVENING AND DURING THE EARLY
OVERNIGHT HOURS BEFORE AREAS OF MORNING STRATUS AND SOME FOG DEVELOP
TOWARD DAYBREAK. HAVE HIGHLIGHTED POTENTIAL FOR A BRIEF PERIOD OF
IFR/LIFR CONDITIONS WITH FOG/STRATUS AT KRWI TUESDAY MORNING WITH
MAINLY MVFR CONDITIONS EXPECTED ELSEWHERE. BKN CLOUDINESS WITH BASES
RANGING FROM 3KFT EAST TO 5KFT WEST ARE EXPECTED ON TUESDAY.
THE WEATHER DURING THE EXTENDED RANGE WILL LARGELY DEPEND ON THE
EVOLUTION OF TROPICAL CYCLONE ISAAC AND A COLD FRONT THAT WILL MOVE
ACROSS THE AREA LATE TUESDAY AND WEDNESDAY. THIS SURFACE BOUNDARY IS
PREDICTED TO STALL OVER THE CAROLINAS. AT THIS TIME... A PERIOD OF
ADVERSE AVIATION CONDITIONS MAY IMPACT THE AREA FROM LATE TUESDAY
THROUGH THURSDAY WITH SUB VFR CEILINGS AS WELL AS SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS. MORE WIDELY SCATTERED SHOWERS
WITH A REDUCED POTENTIAL FOR ADVERSE IMPACT IS EXPECTED ON FRIDAY
AND SATURDAY. -BLAES
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...BLAES
SHORT TERM...CBL
LONG TERM...KRR
AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
933 AM EDT MON AUG 27 2012
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL LINGER JUST OFF THE COAST THROUGH
TONIGHT. A COLD FRONT WILL MOVE IN FROM THE NORTHWEST TUESDAY AND
BECOME STATIONARY OVER THE AREA THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 930 AM MONDAY...SHOWERS AND A FEW TSTMS HAVE FORMED IN AXIS
OF DEEP MOISTURE AND MODERATE INSTABILITY ALONG THE COAST
ASSOCIATED WITH AN INVERTED SURFACE TROUGH AND SOME WEAK SPOKES OF
MID-LEVEL ENERGY ROTATING AROUND THE LARGER CIRCULATION OF
TROPICAL STORM ISSAC IN THE GULF OF MEXICO. LATEST RAP MODEL SHOWS
THIS ACTIVITY PERSISTING THROUGH AFTERNOON WHILE GRADUALLY
SHIFTING INLAND THIS AFTERNOON WHERE BETTER HEATING WILL OCCUR
THIS MORNING WITH THE SEA BREEZE PROVIDING A TRIGGERING MECHANISM.
NO MAJOR CHANGES TO MAX TEMPERATURE FORECAST AS MOST AREAS SHOULD
REACH THE MIDDLE 80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
AS OF 400 AM MON...APPROACHING SHRT WV FROM NW AND ASSCTD SFC FRONT
WILL LEAD TO MORE OF AN INLAND TROF PATTERN TONIGHT WITH SFC WINDS
BECOMING S-SW...WITH SCT SHOWER/ISOLD TSTM THREAT MAINLY ALONG SRN
COASTAL SECTIONS. CANNOT RULE OUT ISOLATED THREAT INLAND WITH
CONTINUED MOIST/UNSTABLE CONDITIONS...THUS WILL CONTINUE WITH
PREVIOUS FCST OF SLGT CHC POPS OVER INLAND SECTIONS AS WELL. RAISED
TEMPS A FEW DEGS IN LINE WITH MOS BLEND...LOW TO MID 70S.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 345 AM MON...MODELS CONVERGING ON A LANDFALL OF ISAAC TO THE
WEST OF THE FL PANHANDLE...AND THIS WOULD HAVE AN INFLUENCE ON
RAINFALL TOTALS ACROSS E NC. DESPITE THE FURTHER WEST
LANDFALL...THERE WILL BE SOME INDIRECT INFLUENCES OF ISAAC ACROSS
THE AREA...NAMELY A PERIOD OF HEAVY RAIN...THOUGH NOT EXPECTING THE
3 TO 5 INCHES AS PREVIOUSLY THOUGHT. HAVE FOLLOWED THE ECM SOLN WITH
REGARD TO TIMING AND LOCATION OF SYNOPTIC FEATURES AND RAINFALL.
A TROUGH OF LOW PRESSURE AND COLD FRONT PROGGED TO MOVE INTO THE
AREA TUE INTO WED...AND AS ISAAC APPROACHES GULF COAST...SOME OF THE
MOISTURE FROM THE STORM WILL BE ABSORBED BY THE TROUGH...AND PROVIDE
E NC WITH INC RAIN CHANCES. INC POPS TUE TO LIKELY ACROSS THE
SOUTHERN TIER...WITH HIGH CHANCE SCT PRECIP FURTHER NORTH. TIMING OF
SHORTWAVE ENERGY WILL BE TUE 18Z...WITH SCT TO NUMEROUS
SHOWERS/THUNDERSTORMS DEVELOPING BY MORNING. THE GFS IS A BIT DRIER
ON TUE WITH A MORE FLAT/PROGRESSIVE TROUGH TO THE NORTH...AND WOULD
LIMIT AMOUNT OF RAIN.
FOR TUE NIGHT...HEAVY RAIN MAY AFFLICT THE REGION...AS AREA WILL BE
UNDER RIGHT EXIT REGION OF JET STREAK WHICH WOULD PROVIDE GOOD
DIVERGENCE ALOFT...AND WITH MOISTURE STREAMING NORTHEASTWARD FROM
ISAAC...FAVORABLE FOR A PERIOD OF HEAVY RAIN AND THUNDERSTORMS. HAVE
INC POPS TO LIKELY...AGAIN WITH THE BEST CHANCES ACROSS SOUTHERN
PORTIONS OF THE CWA. RAIN AND STORMS WILL LINGER INTO WED BEFORE
HIGH PRES BEGINS TO RIDGE IN AT THE SFC. ATTM A GENERAL 1 TO 2
INCHES OF RAIN IS NOT OUT OF THE QUESTION...WITH SOME HIGHER AMOUNTS
WHERE HEAVIER STORMS DEVELOP. NOT EXPECTING ANY SEVERE THUNDERSTORMS
AS LARGE INSTABILITY VALUES AND SIGNIFICANT SHEAR WILL BE LACKING...
AND MAIN THREAT WILL BE LOCALIZED FLOODING. SHOULD GFS SOLN PAN
OUT...RAIN TOTALS WILL BE LESS THAN CURRENTLY FCST.
BOTH MODELS IN AGREEMENT ON HIGH PRES BOTH SFC AND ALOFT BUILDING
INTO THE AREA MID TO LATE WEEK...AND PRECIP CHANCES WILL DIMINISH
AFTER WED. TEMPS TUE AND WED WILL BE HELD DOWN WITH HIGHS AROUND 80
DUE TO RAIN AND CLOUDS...BEFORE CLIMBING BACK INTO THE MID TO UPPER
80S LATE WEEK.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
SHORT TERM /THROUGH 12Z TUESDAY/
AS OF 655 AM MON...LIGHT ONSHORE LOW LVL FLOW AND MOIST LOW LVLS HAS
RESULTED IN IFR STRATUS/FOG ALL BUT KEWN PAST FEW HOURS...AND
EXPECTED TO CONTINUE NEXT 1-2 HRS. SCT SHOWERS/ISOLD TSTMS ALONG SRN
COASTAL SECTIONS WILL SPREAD/DEVELOP INLAND DURING MORNING...WITH
CONTINUED CONVECTIVE THREAT THROUGH AFTN...AND WILL CARRY FEW HOURS
OF VCTS ALL SITES. ISOLATED ACTIVITY CANNOT BE RULED OUT DURING
EVENING AND OVERNIGHT BUT PROBABILITIES TOO LOW FOR FCST MENTION.
PTCHY IFR FOG/STRATUS LIKELY AGAIN OVERNIGHT.
LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 4 AM MON...SCT TO NUMEROUS SHOWERS AND STORMS EXPECTED TUE
AND WED...AND WILL SEE CONDITIONS DROP TO MVFR AND POTENTIALLY IFR
IN THE RAIN AND CLOUDS. CONDITIONS IMPROVE BY WED NIGHT AND ESP
THUR AS HIGH PRES BUILDS IN.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/
AS OF 935 AM MONDAY...A GENERALLY LIGHT SE/S WIND SHOULD BECOME
MORE SOUTHWEST THIS AFTERNOON AS INVERTED SURFACE TROUGH FEATURE
WEAKENS AND MOVES INLAND. NO MAJOR CHANGES NEEDED TO CURRENT
FORECAST AS WW3 AND SWAN AGREE ON LONGER PERIOD SE SWELL KEEPING
SEAS MAINLY 4-5 FT DURING PERIOD.
LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 4 AM MON...SW FLOW WILL BE AROUND 10 TO 15 KT TUE...SWITCHING
TO E AND NE ON WED 5 TO 10 KT AS A TROUGH AND COOL FRONT DIP DOWN
INTO THE AREA. SCT TO NUMEROUS SHOWERS/STORMS EXPECTED ON TUE AND
WED AS MOISTURE FROM ISAAC IN COMBINATION WITH THE TROUGH AND COLD
FRONT PRODUCE UNSETTLED WEATHER. E AND NE WINDS WILL SWITCH TO SOUTH
ON FRI AND SAT AS HIGH PRES MOVES EAST OF THE AREA.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR NCZ095-
103-104.
MARINE...NONE.
&&
$$
SYNOPSIS...HSA
NEAR TERM...CTC
SHORT TERM...HSA
LONG TERM...TL
AVIATION...JBM/TL
MARINE...JBM/CTC/TL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
344 PM CDT MON AUG 27 2012
.SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT...
SIGNIFICANT FIRE WEATHER CONCERNS CONTINUE THROUGH THE SHORT TERM
PERIOD. SEE DISCUSSION BELOW FOR DETAILS. OTHER THAN FIRE
WEATHER...MAIN CONCERNS ARE POTENTIAL FOR ELEVATED STORMS TONIGHT.
A 30 TO 40 KT LOW LEVEL JET MAY SUPPORT STORMS FROM LATE EVENING
THROUGH THE OVERNIGHT HOURS...ESPECIALLY THROUGH THE JAMES RIVER
VALLEY AND NORTH NEAR THE TURTLE MOUNTAINS. THE 18Z NAM12 AND THE
MOST RECENT HRRR BOTH DEVELOP STORMS IN THIS AREA BY 06Z THIS
EVENING. THE MAIN THREAT WOULD BE ISOLATED LARGE HAIL AROUND
QUARTER SIZE. FOR TUESDAY...HAVE OPTED TO REMOVE POPS THROUGH THE
DAY. EXPECT CONTINUED WARMING...WITH HIGHS REACHING THE 90S MOST
LOCATIONS...AND PERHAPS THE 100 DEGREE MARK IN THE FAR SOUTHWEST.
.LONG TERM...WEDNESDAY THROUGH MONDAY...
HIGHLIGHTS OF THE LONG TERM WILL BE HOT CONDITIONS ON WEDNESDAY
WITH THE POTENTIAL FOR CRITICAL FIRE WEATHER CONDITIONS WEDNESDAY
INTO THURSDAY.
A VERY WARM WEDNESDAY IS EXPECTED ACROSS WESTERN AND CENTRAL NORTH
DAKOTA IN THE WARM SECTOR OF A SURFACE LOW ACROSS SOUTHEAST
SASKATCHEWAN. WIDESPREAD HIGHS IN THE UPPER 90S ARE FORECAST FOR
MUCH OF THE AREA...WITH LOWER 100S POSSIBLE ACROSS THE SOUTHWEST
WHERE WINDS DO BEGIN TO DOWN SLOPE AS THEY TURN SOUTHWEST AHEAD OF
AN APPROACHING COLD FRONT. THIS COLD FRONT IS FORECAST TO ENTER
THE FAR WEST BY WEDNESDAY EVENING AND EXIT THE CWA BY LATE
THURSDAY MORNING. SEE THE FIRE WEATHER DISCUSSION BELOW IN REGARDS
TO THE POTENTIAL FOR CRITICAL FIRE WEATHER CONDITIONS BOTH AHEAD
OF AND BEHIND THE FRONT WEDNESDAY AND WEDNESDAY NIGHT.
THEREAFTER...TEMPERATURES TREND NEAR NORMAL FOR THE REMAINDER OF
THE EXTENDED. IN REGARDS TO PRECIPITATION...OTHER THAN VERY
ISOLATED CONVECTION WEDNESDAY EVENING AND NIGHT WITH COLD FRONTAL
PASSAGE...THE NEXT BEST CHANCE OF CONVECTION IS SATURDAY WITH THE
APPROACH OF THE NEXT UPPER LEVEL WAVE. HOWEVER...THIS MAY BE
DEPENDENT UPON THE TRACK AND INTERACTION OF THE REMNANTS OF ISAAC
THROUGH THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD FOR ALL
TERMINALS. THERE IS A SLIGHT CHANCE THUNDERSTORMS COULD IMPACT
KBIS/KJMS STARTING LATE MONDAY EVENING...HOWEVER...THERE IS SOME
UNCERTAINTY IN COVERAGE AND EXACT TIMING.
&&
.FIRE WEATHER...
A PROLONGED PERIOD OF POTENTIALLY CRITICAL FIRE WEATHER CONDITIONS
IS POSSIBLE THIS AFTERNOON THROUGH AT LEAST WEDNESDAY NIGHT.
FOR THE REMAINDER OF TODAY...A RED FLAG WARNING REMAINS IN EFFECT
FOR BOWMAN...SLOPE...GOLDEN VALLEY...BILLINGS...MCKENZIE AND STARK
COUNTIES UNTIL 9 PM MDT. SOUTHEAST WINDS TO 25 MPH WILL CONTINUE
THROUGH THE EVENING...WITH RELATIVE HUMIDITIES NEAR 20 PERCENT AND
TEMPERATURES NEAR 90. SOUTHEAST WINDS WILL DECREASE TO 10 MPH
AFTER SUNSET WITH RELATIVE HUMIDITIES RECOVERING TO NEAR 80
PERCENT TONIGHT.
FOR TUESDAY IN THE FAR SOUTHWEST...HIGHS WILL BE IN THE UPPER 90S
WITH AFTERNOON RELATIVE HUMIDITIES AROUND 15 PERCENT. WINDS AT 10
MPH OR LESS MAY BE HIGHLY VARIABLE IN DIRECTION...WHICH COULD
CAUSE FIRE CONTROL ISSUES PER COORDINATION WITH ND FIRE PERSONNEL.
FOR WEDNESDAY...CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE
ALONG AND WEST OF HIGHWAY 83. HIGHS NEAR 100...WINDS SOUTH AROUND
20 MPH AND RELATIVE HUMIDITIES NEAR 20 PERCENT ARE POSSIBLE. A
COLD FRONT MOVING THROUGH NORTH DAKOTA WEDNESDAY EVENING MAY
RESULT IN MIXING SUFFICIENT TO MAINTAIN LOW RELATIVE HUMIDITIES
THROUGH THE NIGHT. WINDS WILL SHIFT WEST BEHIND THE FRONT.
ISOLATED THUNDERSTORMS WITH DRY LIGHTNING ARE ALSO POSSIBLE
WEDNESDAY EVENING AND NIGHT. CONDITIONS WEDNESDAY EVENING AND
NIGHT WILL BE SIMILIAR TO THOSE SEEN ON FRIDAY NIGHT. FIRE WEATHER
CONCERNS MAY CONTINUE INTO THURSDAY FOR PORTIONS OF THE
AREA...HOWEVER...WILL HOLD OFF ON ANY FIRE WEATHER HEADLINES FOR
NOW.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY
MORNING FOR NDZ001>003-009>011-017>021-031>035-040>046.
RED FLAG WARNING UNTIL 10 PM CDT /9 PM MDT/ THIS EVENING FOR
NDZ017-031>033-040-043.
FIRE WEATHER WATCH FROM TUESDAY AFTERNOON THROUGH TUESDAY
EVENING FOR NDZ031-032-040-043.
&&
$$
SHORT TERM...RK
LONG TERM/AVIATION/FIRE....AYD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
656 AM EDT MON AUG 27 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE OHIO VALLEY THROUGH THIS
EVENING...BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE
REGION. HIGH PRESSURE WILL THEN BUILD IN ACROSS THE GREAT LAKES
THROUGH THE REST OF THE WORK WEEK...RESULTING IN DRY CONDITIONS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WIDESPREAD SHOWER ACTIVITY ALONG WITH SOME EMBEDDED THUNDERSTORMS
IS PUSHING SLOWLY EAST ACROSS NORTHERN INDIANA OVER INTO NORTHWEST
OHIO THIS MORNING. SHOWER ACTIVITY TO THE SOUTHWEST OF THIS IS MORE
SCATTERED...STRETCHING DOWN INTO SOUTHERN ILLINOIS. THE PCPN IS
ASSOCIATED WITH A MID LEVEL SHORT WAVE ALONG WITH A WEAK COLD
FRONT THAT IS FORECAST TO PUSH EAST ACROSS OUR AREA THIS
AFTERNOON. STILL EXPECT THE HIGHEST POPS TO BE ACROSS OUR
NORTH...CLOSER TO THE TRACK OF THE SHORT WAVE. HOWEVER...THE LAST
FEW RUNS OF THE HRRR ARE TRYING TO DEVELOP SOME BETTER PCPN ACROSS
CENTRAL PORTIONS OF OUR FA...AND THIS SEEMS TO BE GETTING SOME
SUPPORT BY THE LATEST RAP AND EVEN THE 00Z NAM. INTERESTINGLY...THE
NAM IS MAINTAINING A COMPACT 20-30 KNOT 850 KNOT JET AS IT PIVOTS
ACROSS THE AREA THROUGH THIS AFTERNOON. TEMPERATURE FORECAST AND
INSTABILITY ARE SOMEWHAT PROBLEMATIC DEPENDING ON HOW FAST CLOUDS/PCPN
OVERSPREAD THE AREA THROUGH THE REMAINDER OF THE MORNING/EARLY AFTERNOON.
THIS COULD KEEP PCPN MORE SHOWERY WITH SOME EMBEDDED ISOLATED TO
SCATTERED THUNDERSTORMS. EXPECT WARMEST TEMPERATURES TO BE ACROSS
OUR SOUTHEAST WHERE CLOUDS/PCPN SHOULD ARRIVE LAST. WILL RANGE
HIGHS FROM THE LOWER 80S NORTHWEST TO MID AND UPPER 80S ACROSS THE
SOUTHEAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
PCPN SHOULD GENERALLY TAPER OFF THROUGH THE OVERNIGHT HOURS AS
SHORT WAVE PUSHES OFF TO THE EAST. HOWEVER...IT WILL BE TOUGH TO
RULE OUT SOME LINGERING SHOWERS ACROSS THE SOUTH AS THE FRONT
LINGERS ALONG THE OHIO RIVER. HIGH PRESSURE WILL THEN BUILD DOWN
ACROSS THE GREAT LAKES TUESDAY INTO WEDNESDAY. HIGHS BOTH DAYS
WILL BE IN THE LOW TO MID 80S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LARGE SFC HIGH PRESSURE STRETCHING FROM THE EASTERN GREAT LAKES BACK
INTO THE PLAINS WILL DOMINATE THE REGIONS WEATHER AT THE BEGINNING
OF THE PERIOD. THE HIGH BEGINS TO TRANSITION EASTWARD ON THURSDAY
ALLOWING ROOM FOR ISAAC TO MAKE LANDFALL.
THE OFFICIAL TRACK OF ISAAC HAS TRENDED W TODAY...FOLLOWING A GOOD
NUMBER OF THE OPERATIONS MODELS TRENDS. THE 12Z GFS IS THE FARTHEST
W WITH THE LANDFALL...PUSHING IT INLAND AROUND PORT ARTHUR TX. THE
CANADIAN AND NOGAPS ARE CLOSE TO THE NHC TRACK WITH LANDFALL IN
MS...WHILE THE 12Z ECMWF BRINGS IT ONSHORE IN ALABAMA.
THERE IS A WIDE SPREAD IN PATH AFTER LANDFALL. THE GFS TAKES THE LOW
INTO PLAINS BEFORE RECURVING UP THE OHIO VALLEY. THE OTHER MODELS
TAKE THE CIRCULATION UP THROUGH THE MS VALLEY OR WRN TN/KY AT
VARYING SPEEDS. CONFIDENCE IS LOW WITH THE WEEKEND FORECAST. THE
TREND OF THE MODELS WITH ISAAC HAS BEEN WESTWARD...SO IT COULD MAKE
LANDFALL IN LOUISIANA OR ERN TX. IF IT GOES THIS FAR W...THE ONSET
OF THE PCPN COULD BE DELAYED OR IT COULD DRY UP.
FOR NOW...FOLLOWED THE HPC SOLUTION WHICH BRINGS THE SFC LOW TO WRN
KY BY SATURDAY MORNING AND LOW CHC PCPN UP INTO THE REGION FRIDAY.
CHANCE OF PCPN SHOULD INCREASE OVER THE WEEKEND...BUT KEPT POPS IN
THE CHC CATEGORY FOR NOW.
AS THE HIGH SLIDES EAST BY THURSDAY...TEMPERATURES WILL BEGIN TO
WARM....WITH HIGHS IN THE MID 80S TO LOWER 90S. THEY COULD GET A
LITTLE WARMER WITH THE SUBSIDENCE AHEAD OF THE HURRICANE...SO WILL
HAVE TO KEEP AN EYE ON THE THIS IN LATER FORECASTS. WITH CLOUDS
AND PCPN WORKING IN FOR THE END OF THE FA PERIOD...LOWERED
TEMPERATURES BACK INTO THE LOWER TO MID 80S FOR SATURDAY AND
SUNDAY...BUT THEY COULD BE COOLER THE PCPN HOLDS TOGETHER MORE.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
CLOUDS WILL CONTINUE TO SPREAD ACROSS THE AREA THIS MORNING
AHEAD OF AN APPROACHING COLD FRONT. CONVECTION ACROSS INDIANA
WILL GRADUALLY WEAKEN AS IT MOVES INTO OUR AREA THIS
MORNING...HOWEVER SOME OF THIS ACTIVITY SHOULD HOLD TOGETHER TO
PRODUCE LIGHT RAIN AND A FEW RUMBLES OF THUNDER...MAINLY ACROSS
THE WESTERN TERMINALS. THE FRONTAL BOUNDARY WILL PROGRESS EASTWARD
ACROSS THE AREA DURING THE DAY. ADDITIONAL THUNDERSTORM
DEVELOPMENT WILL BE POSSIBLE JUST AHEAD THIS FRONT DURING THE
AFTERNOON. WINDS WILL GRADUALLY SHIFT FROM SOUTHWEST TO NORTHWEST
AS THE FRONT PASSES LATER TODAY.
SOME UNCERTAINTY REMAINS REGARDING THE EVOLUTION OF LOW CIGS
CURRENTLY ACROSS ILLINOIS AND INDIANA. THIS DECK SHOULD LIFT AFTER
SUNRISE ALLOWING FOR CIGS TO REMAIN VFR IN OUR AREA AS THE FRONT
MOVES THROUGH. HOWEVER...THERE IS THE POSSIBILITY OF MVFR CIGS
DEVELOPING TONIGHT BEHIND THE FRONT IN THE NORTHERLY FLOW.
.OUTLOOK...NO SIGNIFICANT WEATHER.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...JGL
SHORT TERM...JGL
LONG TERM...SITES
AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
333 AM EDT MON AUG 27 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE OHIO VALLEY THROUGH THIS
EVENING...BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE
REGION. HIGH PRESSURE WILL THEN BUILD IN ACROSS THE GREAT LAKES
THROUGH THE REST OF THE WORK WEEK...RESULTING IN DRY CONDITIONS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WIDESPREAD SHOWER ACTIVITY ALONG WITH SOME EMBEDDED THUNDERSTORMS
IS PUSHING SLOWLY EAST ACROSS NORTHERN INDIANA OVER INTO NORTHWEST
OHIO THIS MORNING. SHOWER ACTIVITY TO THE SOUTHWEST OF THIS IS MORE
SCATTERED...STRETCHING DOWN INTO SOUTHERN ILLINOIS. THE PCPN IS
ASSOCIATED WITH A MID LEVEL SHORT WAVE ALONG WITH A WEAK COLD
FRONT THAT IS FORECAST TO PUSH EAST ACROSS OUR AREA THIS
AFTERNOON. STILL EXPECT THE HIGHEST POPS TO BE ACROSS OUR
NORTH...CLOSER TO THE TRACK OF THE SHORT WAVE. HOWEVER...THE LAST
FEW RUNS OF THE HRRR ARE TRYING TO DEVELOP SOME BETTER PCPN ACROSS
CENTRAL PORTIONS OF OUR FA...AND THIS SEEMS TO BE GETTING SOME
SUPPORT BY THE LATEST RAP AND EVEN THE 00Z NAM. INTERESTINGLY...THE
NAM IS MAINTAINING A COMPACT 20-30 KNOT 850 KNOT JET AS IT PIVOTS
ACROSS THE AREA THROUGH THIS AFTERNOON. TEMPERATURE FORECAST AND
INSTABILITY ARE SOMEWHAT PROBLEMATIC DEPENDING ON HOW FAST CLOUDS/PCPN
OVERSPREAD THE AREA THROUGH THE REMAINDER OF THE MORNING/EARLY AFTERNOON.
THIS COULD KEEP PCPN MORE SHOWERY WITH SOME EMBEDDED ISOLATED TO
SCATTERED THUNDERSTORMS. EXPECT WARMEST TEMPERATURES TO BE ACROSS
OUR SOUTHEAST WHERE CLOUDS/PCPN SHOULD ARRIVE LAST. WILL RANGE
HIGHS FROM THE LOWER 80S NORTHWEST TO MID AND UPPER 80S ACROSS THE
SOUTHEAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
PCPN SHOULD GENERALLY TAPER OFF THROUGH THE OVERNIGHT HOURS AS
SHORT WAVE PUSHES OFF TO THE EAST. HOWEVER...IT WILL BE TOUGH TO
RULE OUT SOME LINGERING SHOWERS ACROSS THE SOUTH AS THE FRONT
LINGERS ALONG THE OHIO RIVER. HIGH PRESSURE WILL THEN BUILD DOWN
ACROSS THE GREAT LAKES TUESDAY INTO WEDNESDAY. HIGHS BOTH DAYS
WILL BE IN THE LOW TO MID 80S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LARGE SFC HIGH PRESSURE STRETCHING FROM THE EASTERN GREAT LAKES BACK
INTO THE PLAINS WILL DOMINATE THE REGIONS WEATHER AT THE BEGINNING
OF THE PERIOD. THE HIGH BEGINS TO TRANSITION EASTWARD ON THURSDAY
ALLOWING ROOM FOR ISAAC TO MAKE LANDFALL.
THE OFFICIAL TRACK OF ISAAC HAS TRENDED W TODAY...FOLLOWING A GOOD
NUMBER OF THE OPERATIONS MODELS TRENDS. THE 12Z GFS IS THE FARTHEST
W WITH THE LANDFALL...PUSHING IT INLAND AROUND PORT ARTHUR TX. THE
CANADIAN AND NOGAPS ARE CLOSE TO THE NHC TRACK WITH LANDFALL IN
MS...WHILE THE 12Z ECMWF BRINGS IT ONSHORE IN ALABAMA.
THERE IS A WIDE SPREAD IN PATH AFTER LANDFALL. THE GFS TAKES THE LOW
INTO PLAINS BEFORE RECURVING UP THE OHIO VALLEY. THE OTHER MODELS
TAKE THE CIRCULATION UP THROUGH THE MS VALLEY OR WRN TN/KY AT
VARYING SPEEDS. CONFIDENCE IS LOW WITH THE WEEKEND FORECAST. THE
TREND OF THE MODELS WITH ISAAC HAS BEEN WESTWARD...SO IT COULD MAKE
LANDFALL IN LOUISIANA OR ERN TX. IF IT GOES THIS FAR W...THE ONSET
OF THE PCPN COULD BE DELAYED OR IT COULD DRY UP.
FOR NOW...FOLLOWED THE HPC SOLUTION WHICH BRINGS THE SFC LOW TO WRN
KY BY SATURDAY MORNING AND LOW CHC PCPN UP INTO THE REGION FRIDAY.
CHANCE OF PCPN SHOULD INCREASE OVER THE WEEKEND...BUT KEPT POPS IN
THE CHC CATEGORY FOR NOW.
AS THE HIGH SLIDES EAST BY THURSDAY...TEMPERATURES WILL BEGIN TO
WARM....WITH HIGHS IN THE MID 80S TO LOWER 90S. THEY COULD GET A
LITTLE WARMER WITH THE SUBSIDENCE AHEAD OF THE HURRICANE...SO WILL
HAVE TO KEEP AN EYE ON THE THIS IN LATER FORECASTS. WITH CLOUDS
AND PCPN WORKING IN FOR THE END OF THE FA PERIOD...LOWERED
TEMPERATURES BACK INTO THE LOWER TO MID 80S FOR SATURDAY AND
SUNDAY...BUT THEY COULD BE COOLER THE PCPN HOLDS TOGETHER MORE.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS ARE EXPECTED THROUGHOUT TONIGHT. MID AND HIGH
LEVEL CLOUDS WILL SPREAD ACROSS THE AREA DURING THE MORNING HOURS
AHEAD OF AN APPROACHING COLD FRONT. CONVECTION ACROSS INDIANA WILL
GRADUALLY WEAKEN AS IT MOVES INTO OUR AREA THIS MORNING...HOWEVER
SOME OF THIS ACTIVITY SHOULD HOLD TOGETHER TO PRODUCE LIGHT RAIN
MAINLY ACROSS THE WESTERN TERMINALS. BY THIS AFTERNOON...THE
FRONTAL BOUNDARY WILL PUSH EAST ACROSS THE AREA WITH SOME
THUNDERSTORM ACTIVITY DEVELOPING JUST AHEAD OF IT. ENOUGH
UNCERTAINTY STILL REMAINS IN TIMING FOR THIS CONVECTION...SO HAVE
HELD OF ON ANY TEMPOS FOR NOW. ALONG THE FRONTAL BOUNDARY...MVFR
CIGS WILL BE POSSIBLE...MAINLY ACROSS THE NORTHWEST THIS
AFTERNOON. MODELS ARE ALSO HINTING AT POTENTIAL LOWER CIGS TONIGHT
AS COLD ADVECTION MAY DEVELOP A LOW STRATUS DECK ACROSS THE EAST. WILL
CONTINUE TO MONITOR TRENDS FOR THIS POSSIBILITY.
.OUTLOOK...NO SIGNIFICANT WEATHER.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...JGL
SHORT TERM...JGL
LONG TERM...SITES
AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
534 PM EDT MON AUG 27 2012
.SYNOPSIS...
A COLD FRONT WILL BRING SHOWERS TO THE REGION THIS AFTERNOON AND
OVERNIGHT. COOLER DRIER AIR BUILDS IN BEHIND THE FRONT AS DOES A
SURFACE ANTICYCLONE IN THE NORTHWESTERLY FLOW. TOWARD THE END OF
THE WEEK A 5940M CLOSED HIGH BUILDS JUST TO OUR SOUTH AND A SURGE
OF VERY WARM AIR MOVES INTO THE REGION IMPLYING VERY WARM WEATHER
THURSDAY THROUGH AT LEAST SATURDAY. MOISTURE VALUES ARE LOW SO THE
HEAT LATER THIS WEEK AND WEEKEND SHOULD BE WITH RELATIVELY DRY
AIR.
&&
.NEAR TERM /UNTIL MIDNIGHT TONIGHT/...
LIGHT RAIN AND SHOWERS ARE IN EXTREME NORTHWESTERN WARREN COUNTY
AND WORKING SLOWLY TO THE EAST. RATHER SUNNY IN CENTRAL
PENNSYLVANIA AND INTO THE SUSQUEHANNA VALLEY.
MOST GUIDANCE SUGGESTS RAIN WILL SLOWLY WORK ITS WAY EAST AND THUS
MOST CENTRAL AND EASTERN AREAS SHOULD REMAIN RAIN FREE UNTIL AFTER
DARK.
NOT A LOT OF INSTABILITY BUT SO SHOWERS WILL DOMINATE WITH SOME
ISOLATED EMBEDDED THUNDERSTORMS. THE SECOND AREA OF RAIN OVER OHIO
AND SOUTHERN LAKE ERIE WILL LIKELY BE THE FEATURE TO ENSURE BETTER
RAIN...PUT NEAR 100 PERCENT CHANCE IN NORTHWESTERN AREAS...THIS
EVENING. FEATURE AS AN VORTEX LIKE APPEARANCE TOO. LEANED TOWARD
THE 4KM NAM AT 1200 UTC AND SREF FOR SOLUTION. HRRR LOOKED A BIT
OVER DONE.
&&
.SHORT TERM /MIDNIGHT TONIGHT THROUGH TUESDAY NIGHT/...
BLENDED MODELS AND SREF TO GET POPS/QPF AFTER 0000 UTC. KEPT VERY
HIGH POPS IN NORTH AND LOWER POPS IN SOUTH...LOWEST IN SOUTHEAST.
THE FRONT IS MORE SW TO NE IN ORIENTATION AND ALL FORECAST SYSTEMS
SHOW VERY LOW QPF AND POPS AS ONE MOVES SOUTH AND EAST INTO PA.
QPF ABOUT 0.50 OR MORE MOST LIKELY IN NORTHERN REGIONS AND NOT
MUCH TO SPEAK OF IN SOUTHEAST.
LIKED 0900 UTC SREF AND 4KM NAM CLEARING OUT MOST OF THE CLOUDS NW
TO SE AFTER 0600 UTC AND GETTING MOST MENTION OF POPS OUT EVEN IN
EAST A FEW HOURS EITHER SIDE OF 1200 UTC TUESDAY.
PUT SOME FOG IN NORTHWEST TOWARD SUNRISE BEHIND THE FRONT AND IN
REGION WHERE EXPECT HIGHEST PROBABILITY OF RAINFALL AND THUS
MOISTURE IN THE BOUNDARY LAYER.
AFTERNOON LOOKS REALLY GOOD EVERYWHERE TUESDAY SO DROPPED ANY POPS
TO GENERATE SHOWERS AFTER ABOUT 1500 UTC. SHOULD BE WARM IN
SOUTHEAST INTO AFTERNOON. BUT VERY PLEASANT ACROSS REGION TOWARD
EVENING WITH LOWERED DEW POINTS AND LIGHT WINDS. THOSE WANTING
REAL HEAT WILL HAVE TO WAIT UNTIL PERHAPS FRIDAY AFTERNOON!
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
CONFIDENCE IN THE FIRST PART OF THE FCST PERIOD REMAINS ABOVE
AVERAGE...AS ALL MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE BUILDS
A SFC HIGH PRES AND ABNORMALLY DRY /BLW NORMAL PWAT/ AIR FROM THE
GREAT LAKES REGION SEWD ACROSS THE MID-ATLANTIC STATES. THIS WILL
RESULT IN FAIR AND DRY WX WED-FRI...WITH INCREASINGLY HOT CONDS
EXPECTED BY THE END OF THE WEEK. IN FACT...THERE IS A CLEAR TREND
TOWARD A BRIEF HEAT WAVE AROUND THE END OF THE WEEK...AS AN
ANOMALOUS H5 RIDGE MIGRATES ATOP OF THE TROPICAL CYCLONE. 12Z GEFS
AND 00Z ECMWF ENSEMBLE DATA BOTH SHOW 850MB TEMPS ARND 18-20C BY
FRI-SAT...AND THEREFORE BOOSTED MAXES A FEW DEGS ABV MOS GUID
AND CLOSER TO THE 18Z HPC FINALS. REASON BEING...THE INHERENT CLIMO
BIAS IS LKLY HOLDING MOS TEMPS DOWN TOO LOW. THIS SHOULD TRANSLATE
INTO 90F DEGREE TEMPS IN THE CENTRAL AND SOUTHEASTERN VALLEYS.
THE NRN STREAM FLOW ALOFT SHOULD BECOME MORE PROGRESSIVE/ZONAL
DURING THE SECOND HALF OF THE PERIOD...AS THE H5 RIDGE SHIFTS OFF
THE SE COAST. THIS WOULD ALLOW THE TRANSITIONING TROPICAL CYCLONE
AND ASSOCIATED MOISTURE TO GET PICKED UP IN THE WESTERLIES...WITH
SOME RE-CURVATURE AND EWD ACCELERATION POSSIBLE BY THE END OF THE
WEEKEND. THE FASTER FLOW ALOFT COMBINED WITH THE INFLUENCE OF
ISSAC LEADS TO BELOW AVG CONFIDENCE...AS THE MODELS BECOME OUT OF
PHASE INTO EARLY NEXT WEEK. THEREFORE...UTILIZED A BLENDED SOLUTION
COMPRISED OF EC/GFS/HPC GRIDDED DATA FOR DAYS 6-8 /SAT-MON/. IN
GENERAL EXPECT A MORE UNSETTLED PATTERN TO UNFOLD WITH AN
INCREASED CHANCE FOR RAIN AND OTHER POTENTIAL IMPACTS ASSOC WITH
THE REMNANTS OF ISAAC.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
COLD FRONT IN E OHIO IS CREATING LARGE AREA OF SHOWERS/LIGHT RAIN
IN W PA AND NORTHERN MTNS. MUCH OF AREA NORTH OF I-80 SEEIGN
SHOWERS...WITH ISO TSTMS DEVELOPING NEAR/NORTH OF KIPT AT 22Z.
PRECIP WILL GRADUALLY WORK INTO SW AREAS OVER NEXT SEVERAL
HOURS...BUT TAKE MOST OF THE NIGHT TO GET INTO EXTREME
SOUTHEASTERN AREAS.
BEHIND THE FRONT LATER TONIGHT...NORTHWEST AREAS WILL HAVE MORE
FOG THAN SOUTHEAST /WITH ADDITIONAL MOISTURE DUE TO RAINFALL/. MOST
OF TAFS SHOW LIGHT RAIN BY 03-06Z OR BR AS RAIN LOOKS SPOTTY AS ONE
MOVES SOUTH AND EAST INTO PENNSYLVANIA.
IMPROVING...IF NOT RAPIDLY IMPROVING...CONDITIONS TUESDAY MORNING
AS CLOUDS WITH FRONTAL BOUNDARY SLIDE TO OUR EAST AND PATCHY FOG
IN MORNING BURNS OFF. SHOULD BE MVFR/VFR EVERYWHERE BY 14Z AND VFR
EVERYWHERE BY 1700 UTC.
COMING WEEK LOOKS GOOD PATCH AM FOG AND SUNNY SKIES. NO WEATHER OF
NOTE EXPECTED UNTIL THE WEEKEND OR LATER...BIG BUBBLE NO TROUBLE.
OUTLOOK...
EARLY TUE...CFRONT PASSAGE. SHRA/TSRA POSS.
WED-FRI...VFR POSSIBLE MVFR/IFR PATCH AM FOG.
SAT...MVFR POSS IN SCT RAIN SHOWERS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...STEINBUGL
AVIATION...GRUMM/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
354 PM EDT MON AUG 27 2012
.SYNOPSIS...
A COLD FRONT WILL BRING SHOWERS TO THE REGION THIS AFTERNOON AND
OVERNIGHT. COOLER DRIER AIR BUILDS IN BEHIND THE FRONT AS DOES A
SURFACE ANTICYCLONE IN THE NORTHWESTERLY FLOW. TOWARD THE END OF
THE WEEK A 5940M CLOSED HIGH BUILDS JUST TO OUR SOUTH AND A SURGE
OF VERY WARM AIR MOVES INTO THE REGION IMPLYING VERY WARM WEATHER
THURSDAY THROUGH AT LEAST SATURDAY. MOISTURE VALUES ARE LOW SO THE
HEAT LATER THIS WEEK AND WEEKEND SHOULD BE WITH RELATIVELY DRY
AIR.
&&
.NEAR TERM /UNTIL MIDNIGHT TONIGHT/...
LIGHT RAIN AND SHOWERS ARE IN EXTREME NORTHWESTERN WARREN COUNTY
AND WORKING SLOWLY TO THE EAST. RATHER SUNNY IN CENTRAL
PENNSYLVANIA AND INTO THE SUSQUEHANNA VALLEY.
MOST GUIDANCE SUGGESTS RAIN WILL SLOWLY WORK ITS WAY EAST AND THUS
MOST CENTRAL AND EASTERN AREAS SHOULD REMAIN RAIN FREE UNTIL AFTER
DARK.
NOT A LOT OF INSTABILITY BUT SO SHOWERS WILL DOMINATE WITH SOME
ISOLATED EMBEDDED THUNDERSTORMS. THE SECOND AREA OF RAIN OVER OHIO
AND SOUTHERN LAKE ERIE WILL LIKELY BE THE FEATURE TO ENSURE BETTER
RAIN...PUT NEAR 100 PERCENT CHANCE IN NORTHWESTERN AREAS...THIS
EVENING. FEATURE AS AN VORTEX LIKE APPEARANCE TOO. LEANED TOWARD
THE 4KM NAM AT 1200 UTC AND SREF FOR SOLUTION. HRRR LOOKED A BIT
OVER DONE.
&&
.SHORT TERM /MIDNIGHT TONIGHT THROUGH TUESDAY NIGHT/...
BLENDED MODELS AND SREF TO GET POPS/QPF AFTER 0000 UTC. KEPT VERY
HIGH POPS IN NORTH AND LOWER POPS IN SOUTH...LOWEST IN SOUTHEAST.
THE FRONT IS MORE SW TO NE IN ORIENTATION AND ALL FORECAST SYSTEMS
SHOW VERY LOW QPF AND POPS AS ONE MOVES SOUTH AND EAST INTO PA.
QPF ABOUT 0.50 OR MORE MOST LIKELY IN NORTHERN REGIONS AND NOT
MUCH TO SPEAK OF IN SOUTHEAST.
LIKED 0900 UTC SREF AND 4KM NAM CLEARING OUT MOST OF THE CLOUDS NW
TO SE AFTER 0600 UTC AND GETTING MOST MENTION OF POPS OUT EVEN IN
EAST A FEW HOURS EITHER SIDE OF 1200 UTC TUESDAY.
PUT SOME FOG IN NORTHWEST TOWARD SUNRISE BEHIND THE FRONT AND IN
REGION WHERE EXPECT HIGHEST PROBABILITY OF RAINFALL AND THUS
MOISTURE IN THE BOUNDARY LAYER.
AFTERNOON LOOKS REALLY GOOD EVERYWHERE TUESDAY SO DROPPED ANY POPS
TO GENERATE SHOWERS AFTER ABOUT 1500 UTC. SHOULD BE WARM IN
SOUTHEAST INTO AFTERNOON. BUT VERY PLEASANT ACROSS REGION TOWARD
EVENING WITH LOWERED DEW POINTS AND LIGHT WINDS. THOSE WANTING
REAL HEAT WILL HAVE TO WAIT UNTIL PERHAPS FRIDAY AFTERNOON!
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
CONFIDENCE IN THE FIRST PART OF THE FCST PERIOD REMAINS ABOVE
AVERAGE...AS ALL MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE BUILDS
A SFC HIGH PRES AND ABNORMALLY DRY /BLW NORMAL PWAT/ AIR FROM THE
GREAT LAKES REGION SEWD ACROSS THE MID-ATLANTIC STATES. THIS WILL
RESULT IN FAIR AND DRY WX WED-FRI...WITH INCREASINGLY HOT CONDS
EXPECTED BY THE END OF THE WEEK. IN FACT...THERE IS A CLEAR TREND
TOWARD A BRIEF HEAT WAVE AROUND THE END OF THE WEEK...AS AN
ANOMALOUS H5 RIDGE MIGRATES ATOP OF THE TROPICAL CYCLONE. 12Z GEFS
AND 00Z ECMWF ENSEMBLE DATA BOTH SHOW 850MB TEMPS ARND 18-20C BY
FRI-SAT...AND THEREFORE BOOSTED MAXES A FEW DEGS ABV MOS GUID
AND CLOSER TO THE 18Z HPC FINALS. REASON BEING...THE INHERENT CLIMO
BIAS IS LKLY HOLDING MOS TEMPS DOWN TOO LOW. THIS SHOULD TRANSLATE
INTO 90F DEGREE TEMPS IN THE CENTRAL AND SOUTHEASTERN VALLEYS.
THE NRN STREAM FLOW ALOFT SHOULD BECOME MORE PROGRESSIVE/ZONAL
DURING THE SECOND HALF OF THE PERIOD...AS THE H5 RIDGE SHIFTS OFF
THE SE COAST. THIS WOULD ALLOW THE TRANSITIONING TROPICAL CYCLONE
AND ASSOCIATED MOISTURE TO GET PICKED UP IN THE WESTERLIES...WITH
SOME RE-CURVATURE AND EWD ACCELERATION POSSIBLE BY THE END OF THE
WEEKEND. THE FASTER FLOW ALOFT COMBINED WITH THE INFLUENCE OF
ISSAC LEADS TO BELOW AVG CONFIDENCE...AS THE MODELS BECOME OUT OF
PHASE INTO EARLY NEXT WEEK. THEREFORE...UTILIZED A BLENDED SOLUTION
COMPRISED OF EC/GFS/HPC GRIDDED DATA FOR DAYS 6-8 /SAT-MON/. IN
GENERAL EXPECT A MORE UNSETTLED PATTERN TO UNFOLD WITH AN
INCREASED CHANCE FOR RAIN AND OTHER POTENTIAL IMPACTS ASSOC WITH
THE REMNANTS OF ISAAC.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
COLD FRONT BACK OVER OHIO IS CREATING SHOWERS AND LIGHT RAIN IN
NORTHWESTERN PENNSYLVANIA. LEADING EDGE COULD BE IN KBFD AROUND OR
SHORTLY AFTER 1800 UTC. WILL TAKE MOST OF THE REST OF THE DAY TO
WORK INTO THE SOUTHWESTERN AREAS. MOST OF THE NIGHT TO GET INTO
EXTREME SOUTHEASTERN AREAS.
NORTHWEST AREAS WILL HAVE MORE FOG THAN SOUTHEAST BEHIND THE FRONT
AND WITH ADDITIONAL MOISTURE DUE TO RAINFALL. MOST OF TAFS SHOW
LIGHT RAIN BY 3-0600 UTC OR BR AS RAIN LOOKS SPOTTY AS ONE MOVES
SOUTH AND EAST INTO PENNSYLVANIA.
IMPROVING...IF NOT RAPIDLY IMPROVING...CONDITIONS TUESDAY MORNING
AS CLOUDS WITH FRONTAL BOUNDARY SLIDE TO OUR EAST AND PATCHY FOG
IN MORNING BURNS OFF. SHOULD BE MVFR/VFR EVERYWHERE BY 14Z AND VFR
EVERYWHERE BY 1700 UTC.
COMING WEEK LOOKS GOOD PATCH AM FOG AND SUNNY SKIES. NO WEATHER OF
NOTE EXPECTED UNTIL THE WEEKEND OR LATER...BIG BUBBLE NO TROUBLE.
OUTLOOK...
EARLY TUE...CFRONT PASSAGE. SHRA/TSRA POSS.
WED-FRI...VFR POSSIBLE MVFR/IFR PATCH AM FOG.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...STEINBUGL
AVIATION...GRUMM
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
235 PM EDT MON AUG 27 2012
.SYNOPSIS...
A COLD FRONT WILL BRING SHOWERS TO THE REGION THIS AFTERNOON AND
OVERNIGHT. COOLER DRIER AIR BUILDS IN BEHIND THE FRONT AS DOES A
SURFACE ANTICYCLONE IN THE NORTHWESTERLY FLOW. TOWARD THE END OF
THE WEEK A 5940M CLOSED HIGH BUILDS JUST TO OUR SOUTH AND A SURGE
OF VERY WARM AIR MOVES INTO THE REGION IMPLYING VERY WARM WEATHER
THURSDAY THROUGH AT LEAST SATURDAY. MOISTURE VALUES ARE LOW SO THE
HEAT LATER THIS WEEK AND WEEKEND SHOULD BE WITH RELATIVELY DRY
AIR.
&&
.NEAR TERM /UNTIL MIDNIGHT TONIGHT/...
LIGHT RAIN AND SHOWERS ARE IN EXTREME NORTHWESTERN WARREN COUNTY
AND WORKING SLOWLY TO THE EAST. RATHER SUNNY IN CENTRAL
PENNSYLVANIA AND INTO THE SUSQUEHANNA VALLEY.
MOST GUIDANCE SUGGESTS RAIN WILL SLOWLY WORK ITS WAY EAST AND THUS
MOST CENTRAL AND EASTERN AREAS SHOULD REMAIN RAIN FREE UNTIL AFTER
DARK.
NOT A LOT OF INSTABILITY BUT SO SHOWERS WILL DOMINATE WITH SOME
ISOLATED EMBEDDED THUNDERSTORMS. THE SECOND AREA OF RAIN OVER OHIO
AND SOUTHERN LAKE ERIE WILL LIKELY BE THE FEATURE TO ENSURE BETTER
RAIN...PUT NEAR 100 PERCENT CHANCE IN NORTHWESTERN AREAS...THIS
EVENING. FEATURE AS AN VORTEX LIKE APPEARANCE TOO. LEANED TOWARD
THE 4KM NAM AT 1200 UTC AND SREF FOR SOLUTION. HRRR LOOKED A BIT
OVER DONE.
&&
.SHORT TERM /MIDNIGHT TONIGHT THROUGH TUESDAY NIGHT/...
BLENDED MODELS AND SREF TO GET POPS/QPF AFTER 0000 UTC. KEPT VERY
HIGH POPS IN NORTH AND LOWER POPS IN SOUTH...LOWEST IN SOUTHEAST.
THE FRONT IS MORE SW TO NE IN ORIENTATION AND ALL FORECAST SYSTEMS
SHOW VERY LOW QPF AND POPS AS ONE MOVES SOUTH AND EAST INTO PA.
QPF ABOUT 0.50 OR MORE MOST LIKELY IN NORTHERN REGIONS AND NOT
MUCH TO SPEAK OF IN SOUTHEAST.
LIKED 0900 UTC SREF AND 4KM NAM CLEARING OUT MOST OF THE CLOUDS NW
TO SE AFTER 0600 UTC AND GETTING MOST MENTION OF POPS OUT EVEN IN
EAST A FEW HOURS EITHER SIDE OF 1200 UTC TUESDAY.
PUT SOME FOG IN NORTHWEST TOWARD SUNRISE BEHIND THE FRONT AND IN
REGION WHERE EXPECT HIGHEST PROBABILITY OF RAINFALL AND THUS
MOISTURE IN THE BOUNDARY LAYER.
AFTERNOON LOOKS REALLY GOOD EVERYWHERE TUESDAY SO DROPPED ANY POPS
TO GENERATE SHOWERS AFTER ABOUT 1500 UTC. SHOULD BE WARM IN
SOUTHEAST INTO AFTERNOON. BUT VERY PLEASANT ACROSS REGION TOWARD
EVENING WITH LOWERED DEW POINTS AND LIGHT WINDS. THOSE WANTING
REAL HEAT WILL HAVE TO WAIT UNTIL PERHAPS FRIDAY AFTERNOON!
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
A HIGH CONFIDENCE FCST WED-FRI...AS ALL MED RANGE GUIDANCE BUILDS
SFC HIGH AND LOW PWAT AIR SE ACROSS PA. THUS...ANTICIPATE MCLEAR
SKIES DURING THE SECOND HALF OF THE WEEK. ECMWF MEAN 8H TEMPS
INDICATE HIGHS NR AVERAGE WED...THEN A WARM-UP FOR LATE WEEK...AS HIGH
DRIFTS SE OF PA AND RETURN SW FLOW DEVELOPS. DRY AIR WILL LIKELY
RESULT IN A COUPLE OF COOL NIGHTS AT MIDWEEK...WITH WED NIGHT IN
PARTICULAR LOOKING COOL...AS SFC HIGH DRIFTS DIRECTLY OVR THE
STATE. GEFS AND ECMWF ENSEMBLE DATA BOTH PUSH 850MB TEMPS TO ARND
18C BY LATE WEEK...SO HAVE INCREASED HIGHS FRI/SAT TO NR 90F IN
THE VALLEYS.
AN ADDITIONAL CONCERN HEADING INTO NEXT WEEKEND IS THE REMNANTS
OF ISAAC. BULK OF MED RANGE GUIDANCE TAKE WHAT IS LEFT OF ISAAC
AND CURL IT UP AND OVER THE BUILDING UPPER LEVEL RIDGE NEXT
WEEKEND....WHICH COULD TURN OUR WEATHER UNSETTLED. DUE TO INHERENT
MDL UNCERTAINTIES SO FAR OUT...HAVE CONSERVATIVELY INCREASED POPS
TO ARND 40 PCT BY NEXT WEEKEND.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
COLD FRONT BACK OVER OHIO IS CREATING SHOWERS AND LIGHT RAIN IN
NORTHWESTERN PENNSYLVANIA. LEADING EDGE COULD BE IN KBFD AROUND OR
SHORTLY AFTER 1800 UTC. WILL TAKE MOST OF THE REST OF THE DAY TO
WORK INTO THE SOUTHWESTERN AREAS. MOST OF THE NIGHT TO GET INTO
EXTREME SOUTHEASTERN AREAS.
NORTHWEST AREAS WILL HAVE MORE FOG THAN SOUTHEAST BEHIND THE FRONT
AND WITH ADDITIONAL MOISTURE DUE TO RAINFALL. MOST OF TAFS SHOW
LIGHT RAIN BY 3-0600 UTC OR BR AS RAIN LOOKS SPOTTY AS ONE MOVES
SOUTH AND EAST INTO PENNSYLVANIA.
IMPROVING...IF NOT RAPIDLY IMPROVING...CONDITIONS TUESDAY MORNING
AS CLOUDS WITH FRONTAL BOUNDARY SLIDE TO OUR EAST AND PATCHY FOG
IN MORNING BURNS OFF. SHOULD BE MVFR/VFR EVERYWHERE BY 14Z AND VFR
EVERYWHERE BY 1700 UTC.
COMING WEEK LOOKS GOOD PATCH AM FOG AND SUNNY SKIES. NO WEATHER OF
NOTE EXPECTED UNTIL THE WEEKEND OR LATER...BIG BUBBLE NO TROUBLE.
OUTLOOK...
EARLY TUE...CFRONT PASSAGE. SHRA/TSRA POSS.
WED-FRI...VFR POSSIBLE MVFR/IFR PATCH AM FOG.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...FITZGERALD/EVANEGO
AVIATION...GRUMM
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
823 AM EDT MON AUG 27 2012
.SYNOPSIS...
A COLD FRONT OVER THE GREAT LAKES THIS MORNING WILL PUSH
THROUGH PENNSYLVANIA TONIGHT AND EARLY TUESDAY. HIGH PRESSURE
WILL BUILD SOUTHEAST ACROSS THE REGION DURING THE SECOND HALF OF
THE WORK WEEK. THE REMNANTS OF ISAAC COULD POTENTIALLY AFFECT
PENNSYLVANIA BY NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED FORECAST AND GRIDS TO REFLECT THE CONVECTION AND RADAR NOW
EAST OF OUR COUNTY WARNING AREA. UPDATED FORECAST TO LOWER POPS IN
EASTERN AREAS. STILL POTENTIAL FOR SCATTERED LINGERING SHOWERS IN
A FEW LOCATIONS. BUT DECREASING FAST.
USED IR/VIS BLEND TO MAKE MORNING CLOUDS TO SHOW PARTLY TO MOSTLY
SUNNY IN FAR WESTERN AREAS AND BLENDED INTO FORECASTS WHICH SHOW
CLOUDS OVER OHIO COMING INTO THE NORTHWESTERN AREAS LATER THIS
MORNING...OVER SOME LOWER CLOUDS IN EXTREME NW PA. THE 4KM NAM
DOES NOT BODE WELL FOR SUNNY SKIES...FORMS NEW LOW CLOUDS IN EAST
AS FRONTAL CLOUDS COME IN FROM WEST THIS AFTERNOON...ALWAYS TOMORROW!
BELIEVE THE 16KM IS FAR TOO WET IN EAST TODAY...THOUGH 4KM
NAM...HRRR AND RUC ALL IMPLY ONE LAST UPPER-LOW EASTERLY FLOW BAND
COULD CLIP SE...PERHAPS YORK AND LANCASTER COUNTIES SO KEPT CHANCE
DOWN THERE.
IN WEST MOST GUIDANCE IMPLIES SHOWERS ARRIVING MID-TO-LATE
AFTERNOON IN NW. CAPE IS QUITE MEAGER BUT STILL AUGUST AND SHOWER
WITH THUNDERSTORMS POSSIBLE. BULK OF SHOWERS COULD BE PRETTY LATE
IN EAST AND SOUTHEAST...NEXT PERIOD.
NOT EXPECTING MUCH SEVERE POTENTIAL DUE TO MEAGER CAPE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
MINOR EDITS...SREF AND 06Z 4KM NAM ALL HOW WEAK LINE SHOWERS OVER
CENTRAL PA AT START OF THIS PERIOD. NOT A LOT OF CAPE. MODELS ALSO
SHOW BEST SIMULATED ECHOES OVER CENTRAL AND NORTHERN AREAS.
BOUNDARY GOES SOMEWHAT EAST-WEST. THIS LIMITS QPF IN SOUTHERN
TIER COUNTIES AND SOUTHEAST. THOUGH MODELS SHOW POTENTIAL IN
CENTRAL AREAS OF 0.5 TO 1.0 INCHES OF RAIN.
INDICATIONS ARE CLOUDS AND SHOWER POTENTIAL WILL CONTINUE TO LOWER
TUESDAY. SHOULD BE A PRETTY GOOD AFTERNOON FOR A JOB OR BIKE RIDE
CWA WIDE. NOT SURE WHY THE NEW 16KM SREF LINGERS LOW POPS SO MUCH.
THOUGH AFTER 18Z POPS IN SEE ARE 10-20 PERCENT. EXPECT 09Z SREF TO
LOWER THESE NUMBERS.
PREVIOUS DISCUSSION: COLD FRONT WILL PUSH SE ACROSS THE REGION
TONIGHT...ACCOMPANIED BY SHRA AND A POSS RUMBLE OF THUNDER.
ENSEMBLE DATA SUPPORTS HIGHEST /CATEGORICAL/ POPS ACROSS NORTHERN
PA AND LIKELY POPS ELSEWHERE. ENSEMBLE MEAN QPF RANGES FROM AROUND A
HALF INCH OVR THE NORTH AND LESS THAN A QUARTER INCH SOUTH.
HOWEVER...MUCH HIGHER LOCAL AMTS WILL FALL...GIVEN PWATS CLOSE TO
2 INCHES. ENSEMBLE PROBABILITY CHARTS SUGGEST NORTHERN PA MOST
LIKELY TO SEE LOCALLY HVY AMTS THIS EVENING BTWN 00Z-06Z.
THE COLD FRONT WILL PASS TO OUR SOUTH AND EAST LATE MONDAY NIGHT
OR EARLY TUESDAY...TAKING ANY LINGERING SHRA/TSRA WITH IT. MDLS
TRACK COLD FRONT INTO THE NW MTNS SHORTLY AFTER 06Z...THEN EXITING
THE SE ZONES BY NOON. CLEARING SKIES WILL OVERSPREAD THE REGION
LATE TUE AM...AS MUCH DRIER AIR OVERSPREADS THE STATE. ENS MEAN
850MB TEMPS NR 14C SHOULD SUPPORT HIGHS FROM THE U70S OVR THE
ALLEGHENIES...TO THE M80S OVR THE SUSQ VALLEY. A SECONDARY
SHORTWAVE DIVING ACROSS THE AREA LATE IN THE DAY COULD PRODUCE A
FAIR AMT OF PM CU AND EVEN AN ISOLD LATE DAY -SHRA OVR THE N MTNS.
HOWEVER...WILL LEAVE MENTION OF PRECIP OUT OF FCST FOR NOW AND KEEP
POPS BLW 15PCT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
A HIGH CONFIDENCE FCST WED-FRI...AS ALL MED RANGE GUIDANCE BUILDS
SFC HIGH AND LOW PWAT AIR SE ACROSS PA. THUS...ANTICIPATE MCLEAR
SKIES DURING THE SECOND HALF OF THE WEEK. ECMWF MEAN 8H TEMPS
INDICATE HIGHS NR AVERAGE WED...THEN A WARMUP FOR LATE WEEK...AS HIGH
DRIFTS SE OF PA AND RETURN SW FLOW DEVELOPS. DRY AIR WILL LIKELY
RESULT IN A COUPLE OF COOL NIGHTS AT MIDWEEK...WITH WED NIGHT IN
PARTICULAR LOOKING COOL...AS SFC HIGH DRIFTS DIRECTLY OVR THE
STATE. GEFS AND ECMWF ENSEMBLE DATA BOTH PUSH 850MB TEMPS TO ARND
18C BY LATE WEEK...SO HAVE INCREASED HIGHS FRI/SAT TO NR 90F IN
THE VALLEYS.
AN ADDITIONAL CONCERN HEADING INTO NEXT WEEKEND IS THE REMNANTS
OF ISAAC. BULK OF MED RANGE GUIDANCE TAKE WHAT IS LEFT OF ISAAC
AND CURL IT UP AND OVER THE BUILDING UPPER LEVEL RIDGE NEXT
WEEKEND....WHICH COULD TURN OUR WEATHER UNSETTLED. DUE TO INHERENT
MDL UNCERTAINTIES SO FAR OUT...HAVE CONSERVATIVELY INCREASED POPS
TO ARND 40 PCT BY NEXT WEEKEND.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
A FEW SHOWERS AND ISOLATED STORMS ACROSS EASTERN SECTIONS FOR
A FEW MORE HOURS.
MAIN ISSUE WILL BE LOW CLDS THAT FORMED LAST EVENING. JST ON
THE WEST SIDE OF THIS NOW. SOME FOG...BUT CLDS LIMITED THE FOG
OVERALL.
EXPECT VFR BY LATE MORNING OR EARLY AFT. STILL A SMALL CHC OF
A SHOWER OR STORM.
COLD FRONT MOVES IN FROM THE GREAT LAKES TONIGHT...EXPECT
CONDITIONS TO BECOME MVFR AND IFR IN SOME SPOTS.
IMPROVING CONDITIONS AFTER THIS...AS HIGH PRESSURE BUILDS
TOWARD THE AREA.
OUTLOOK...
EARLY TUE...CFRONT PASSAGE. SHRA/TSRA POSS.
WED-FRI...VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...GRUMM/FITZGERALD
SHORT TERM...GRUMM/FITZGERALD
LONG TERM...FITZGERALD/EVANEGO
AVIATION...MARTIN
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1037 PM CDT TUE AUG 28 2012
.DISCUSSION.../ISSUED AT 855 PM CDT/
FORECAST IN GENERAL IN GOOD SHAPE BUT HAVE MADE MINOR TWEAKS TO
ACCOUNT FOR TEMPERATURE...DEW POINT AND SKY TRENDS. FRONTAL
BOUNDARY HAS SET UP JUST NORTH OF INTERSTATE 90 WITH LIGHT
EASTERLY/NORTHEASTERLY FLOW NORTH OF THE BOUNDARY AND SOUTHERLY FLOW
SOUTH. HAVE INCREASED CLOUD COVER ACROSS PORTIONS OF SOUTH CENTRAL
SOUTH DAKOTA AS LIFTING FROM NEAR 700 MB RESULTS IN A SMALL AMOUNT
OF CIN AND MARGINAL CAPE. EVEN IF A STORM WAS ABLE TO DEVELOP...IT
WOULD BE DIFFICULT TO GET PRECIPITATION TO REACH THE GROUND WITH DRY
SUBCLOUD LAYER. AS A RESULT...HAVE LEFT POPS ALONE FOR THE TIME
BEING. THE WARM AIR ADVECTION IS EXPECTED TO SLOWLY SAG SOUTH OF
THE AREA OVERNIGHT...WORKING INTO NORTH CENTRAL NEBRASKA AFTER 09Z
AND TAKING ASSOCIATED CLOUD COVER WITH IT.
FORECAST LOWS LOOK REASONABLE AND HAVE NOT MADE ANY UPDATES AT THIS
TIME.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED THROUGH 06Z THURSDAY. MAY SEE PATCHY FOG
09Z-13Z WITH VISIBILTY DROPPING TO NEAR 3 MILES AT TIMES IN
SHALLOW FOG.
&&
.PREV DISCUSSION.../ISSUED AT 345 PM CDT/
CURRENTLY SEEING STRONG SOUTHERLY WINDS OUT AHEAD OF AN APPROACHING
BOUNDARY. HAD A GUST TO 45 MPH HERE AT THE AIRPORT IN SIOUX
FALLS...BUT MOST LOCATIONS ARE GUSTING CLOSER TO 30 MPH. A DECENT
700 MB WAVE IS FORECAST TO MOVE ACROSS OUR NORTHEAST TONIGHT. THIS
WILL HELP DRAG A BOUNDARY ACROSS THE AREA LATE THIS AFTERNOON INTO
THE OVERNIGHT. WINDS WILL DIMINISH AFTER SUNSET...BUT WILL TEND TO
TAKE ON AN EASTERLY COMPONENT NORTH OF THIS BOUNDARY...WHILE A
SOUTHERLY BREEZE STAYS UP SOUTH OF INTERSTATE 90. BEST LOW AND MID
LEVEL FORCING STAYS EAST OF OUR AREA...AND WITH VERY LIMITED
MOISTURE...THINK WE STAY DRY. THIS IS SUPPORTED BY THE HRRR AND NAM
WHICH KEEP ELEVATED CONVECTION TO OUR EAST TONIGHT. LOWS SHOULD DROP
INTO THE LOW AND MID 60S NORTH OF THE BOUNDARY...WITH MID AND UPPER
60S TO THE SOUTH.
MODELS HANDLE THE BOUNDARY DIFFERENTLY ON WEDNESDAY. THE NAM IS
SLOWEST TO LIFT IT NORTH...WHILE THE GFS AND ECMWF ARE A BIT
QUICKER. NAM SEEMS TO HANDLE THESE MORE MESOSCALE BOUNDARIES
BETTER...SO TRENDED A BIT TOWARDS ITS SOLUTION. THIS WOULD RESULT
IN LIGHT EASTERLY WINDS TO BEGIN THE DAY...TURING SOUTHERLY AND
INCREASING LATE IN THE DAY. TIMING OF THE BOUNDARY AND WIND INCREASE
WILL BE IMPORTANT FOR FIRE WEATHER CONCERNS. FOR NOW...WINDS ARE
EXPECTED TO STAY BELOW RED FLAG CRITERIA ACROSS THE WHOLE AREA...BUT
IT WILL BE CLOSE...AND A FASTER SOLUTION WITH THE BOUNDARY LIKE THE
ECMWF MAY PUSH THE WINDS OVER 25 MPH. HUMIDITY VALUES STILL EXPECTED
TO DROP BELOW 25 PERCENT SOUTHWEST OF A STORM LAKE TO HURON
LINE...AND INTO THE TEENS WEST OF THE JAMES RIVER. SO DUE TO THE
VERY LOW HUMIDITY AND WIND UNCERTAINTY...WILL LEAVE THE FIRE
WEATHER WATCH AS IS...AND LET THE OVERNIGHT SHIFT VIEW 0Z MODEL
TRENDS WITH REGARDS TO WINDS.
EITHER WAY...IT WILL BE HOT AND DRY WEDNESDAY WITH MOSTLY SUNNY
SKIES. FOLLOWED A BLEND OF THE BIAS CORRECTED NAM AND ECMWF
SOLUTIONS FOR HIGHS...GENERALLY GIVING 90S AND 100S ACROSS THE AREA.
WARMEST TEMPERATURES SHOULD BE NEAR THE MISSOURI RIVER WEST OF THE
JAMES RIVER. THE LACK OF A STRONG WESTERLY COMPONENT OF THE WIND
COULD ACT TO LIMIT MIXING SOMEWHAT...ALTHOUGH POSSIBLE
SUPERADIABATIC HEATING SHOULD OFFSET ANY LACK OF MIXING. EVEN WITH
THE LOW DEWPOINTS...WE MAY HIT HEAT ADVISORY CRITERIA ALONG AND
WEST OF THE JAMES RIVER. SEEMS BORDERLINE IN MOST COUNTIES...WITH
ONLY BRULE AND GREGORY BEING TO BE A GOOD BET TO HIT IT. THUS FOR
COLLABORATION PURPOSES WILL HOLD OFF ON AN ADVISORY AND LET MIDNIGHT
SHIFT TAKE ANOTHER LOOK. /CHENARD
A BROAD MID LEVEL TROUGH MOVING ALONG THE CANADIAN BORDER WILL USHER
IN STRONG SOUTHWESTERLY FLOW WEDNESDAY NIGHT INTO THE BETTER PART OF
THURSDAY. THE RESULT WILL BE WELL MIXED AND BREEZY CONDITIONS WITH
VERY WARM TEMPERATURES. AHEAD OF THE BOUNDARY ON WEDNESDAY
NIGHT...COULD SEE A FEW NOCTURNAL HIGH BASED SHOWERS AND
THUNDERSTORMS ALONG OUR WESTERN BORDER. ANY PRECIPITATION THAT DOES
DEVELOP WOULD BE VERY LIGHT AND SHOULD DISSIPATE QUICKLY BY DAYBREAK
THURSDAY. LOWS WILL BE QUITE MILD...PARTICULARLY INTO SOUTH CENTRAL
SOUTH DAKOTA WHERE STRONG MIXING AND WARM AIR ADVECTION ON THE NOSE
OF THE LOW LEVEL JET SHOULD KEEP LOWS WELL INTO THE LOWER TO MID
70S.
FRONTAL BOUNDARY BEGINS ADVANCING EASTWARD INTO THE FORECAST AREA
EARLY THURSDAY...WHICH IS SLIGHTLY FASTER TIMING THAN PREVIOUS MODEL
RUNS. MODELS ARE IN REASONABLY GOOD AGREEMENT WITH THIS FASTER
TRACK...HOWEVER IT MAKES FOR A TRICKY TEMPERATURE FORECAST. THE WELL
MIXED CONDITIONS AHEAD OF THE FRONT WILL ALLOW FOR HIGHS FROM 100 TO
105 FOR AREAS THAT WILL SEE LONGEST MIXING...LIKELY SOUTH OF A SIOUX
FALLS TO LAKE ANDES LINE AND INTO FAR NORTHWEST IOWA. DEWPOINTS WILL
SIMILARLY PLUMMET IN THE AFTERNOON AND WILL RESULT IN MINIMUM RH
VALUES OF 15 TO 25 PERCENT FOR MUCH OF THE FORECAST AREA. WITH
ATTENDANT BREEZY WINDS...IT LOOKS LIKE ANOTHER POTENTIALLY EXTREME
FIRE WEATHER DAY. WENT AHEAD AND ISSUED A FIRE WEATHER WATCH FOR ALL
BUT THE FAR WESTERN ZONES WHICH WILL MISS OUT ON THE STRONGEST
SOUTHWEST WINDS WITH AN EARLIER FRONTAL PASSAGE.
THE EXTENDED RANGE WILL BE LARGELY DEPENDENT UPON THE TRACK OF THE
REMNANTS OF HURRICANE ISAAC. THE LATEST MODELS ARE IN SOMEWHAT
DECENT AGREEMENT WITH BRINGING THE REMNANTS NORTHWARD INTO THE
OZARKS AREA BY FRIDAY AFTERNOON. WITH UPPER LEVEL RIDGING IN PLACE
OVER THE NORTHERN PLAINS...SUBSIDENCE WILL BRING A DRY WEATHER ON
FRIDAY AND RELATIVELY LIGHT SOUTHEAST WINDS...BUT VERY LITTLE RELIEF
TO THE HEAT. HIGHS WILL REMAIN ABOVE NORMAL WITH READINGS IN THE 90S
HOWEVER HIGHER DEWPOINTS AND THE LIGHT WINDS WILL BRING SOME RELIEF
TO FIRE WEATHER CONCERNS.
MODELS BEGIN CURVING ISAAC A LITTLE MORE NORTHEASTWARD ON FRIDAY
NIGHT AND SATURDAY...WHICH BRINGS THE CENTER WHICH BRINGS THE CENTER
INTO THE MID MISSISSIPPI VALLEY. THE GFS IS SLIGHTLY WEST OF THE
ECMWF TRACK...WHILE THE GEM IS QUITE A BIT FURTHER EAST. IT STILL
LOOKS LIKE THIS SCENARIO WILL KEEP THE PRECIPITATION OUT OF OUR CWA
WITH ONLY SOME CLOUDS OR PERHAPS A STRAY SHOWER IN OUR FAR SOUTHEAST.
INTO EARLY NEXT WEEK...MODELS BEGIN DIVERGING QUITE A BIT WITH THE
POTENTIAL FOR A TROUGH MOVING INTO THE HIGH PLAINS AROUND THE
SATURDAY NIGHT THROUGH SUNDAY NIGHT TIME FRAME. THE GFS AND GEM ARE
MORE PRONOUNCED WITH THIS TROUGH WITH THE GFS BEING THE MOST
AGGRESSIVE. AT THE SAME TIME THE ECMWF WASHES OUT THE TROUGH WITH A
ZONAL FLOW PATTERN. OVERALL...NONE OF THE SOLUTIONS LOOK
PARTICULARLY IMPRESSIVE FOR PRECIPITATION CHANCES. WILL GO WITH
MENTION OF A SLIGHT CHANCE MAINLY IN OUR EAST.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR IAZ300-301.
MN...FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR MNZ900.
NE...FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH
WEDNESDAY EVENING FOR NEZ249.
FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR NEZ249.
SD...FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH
WEDNESDAY EVENING FOR SDZ255-258.
FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR SDZ257-258.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
855 PM CDT TUE AUG 28 2012
.DISCUSSION...
FORECAST IN GENERAL IN GOOD SHAPE BUT HAVE MADE MINOR TWEAKS TO
ACCOUNT FOR TEMPERATURE...DEW POINT AND SKY TRENDS. FRONTAL
BOUNDARY HAS SET UP JUST NORTH OF INTERSTATE 90 WITH LIGHT
EASTERLY/NORTHEASTERLY FLOW NORTH OF THE BOUNDARY AND SOUTHERLY FLOW
SOUTH. HAVE INCREASED CLOUD COVER ACROSS PORTIONS OF SOUTH CENTRAL
SOUTH DAKOTA AS LIFTING FROM NEAR 700 MB RESULTS IN A SMALL AMOUNT
OF CIN AND MARGINAL CAPE. EVEN IF A STORM WAS ABLE TO DEVELOP...IT
WOULD BE DIFFICULT TO GET PRECIPITATION TO REACH THE GROUND WITH DRY
SUBCLOUD LAYER. AS A RESULT...HAVE LEFT POPS ALONE FOR THE TIME
BEING. THE WARM AIR ADVECTION IS EXPECTED TO SLOWLY SAG SOUTH OF
THE AREA OVERNIGHT...WORKING INTO NORTH CENTRAL NEBRASKA AFTER 09Z
AND TAKING ASSOCIATED CLOUD COVER WITH IT.
FORECAST LOWS LOOK REASONABLE AND HAVE NOT MADE ANY UPDATES AT THIS
TIME.
&&
.PREV DISCUSSION.../ISSUED AT 345 PM CDT/
CURRENTLY SEEING STRONG SOUTHERLY WINDS OUT AHEAD OF AN APPROACHING
BOUNDARY. HAD A GUST TO 45 MPH HERE AT THE AIRPORT IN SIOUX
FALLS...BUT MOST LOCATIONS ARE GUSTING CLOSER TO 30 MPH. A DECENT
700 MB WAVE IS FORECAST TO MOVE ACROSS OUR NORTHEAST TONIGHT. THIS
WILL HELP DRAG A BOUNDARY ACROSS THE AREA LATE THIS AFTERNOON INTO
THE OVERNIGHT. WINDS WILL DIMINISH AFTER SUNSET...BUT WILL TEND TO
TAKE ON AN EASTERLY COMPONENT NORTH OF THIS BOUNDARY...WHILE A
SOUTHERLY BREEZE STAYS UP SOUTH OF INTERSTATE 90. BEST LOW AND MID
LEVEL FORCING STAYS EAST OF OUR AREA...AND WITH VERY LIMITED
MOISTURE...THINK WE STAY DRY. THIS IS SUPPORTED BY THE HRRR AND NAM
WHICH KEEP ELEVATED CONVECTION TO OUR EAST TONIGHT. LOWS SHOULD DROP
INTO THE LOW AND MID 60S NORTH OF THE BOUNDARY...WITH MID AND UPPER
60S TO THE SOUTH.
MODELS HANDLE THE BOUNDARY DIFFERENTLY ON WEDNESDAY. THE NAM IS
SLOWEST TO LIFT IT NORTH...WHILE THE GFS AND ECMWF ARE A BIT
QUICKER. NAM SEEMS TO HANDLE THESE MORE MESOSCALE BOUNDARIES
BETTER...SO TRENDED A BIT TOWARDS ITS SOLUTION. THIS WOULD RESULT
IN LIGHT EASTERLY WINDS TO BEGIN THE DAY...TURING SOUTHERLY AND
INCREASING LATE IN THE DAY. TIMING OF THE BOUNDARY AND WIND INCREASE
WILL BE IMPORTANT FOR FIRE WEATHER CONCERNS. FOR NOW...WINDS ARE
EXPECTED TO STAY BELOW RED FLAG CRITERIA ACROSS THE WHOLE AREA...BUT
IT WILL BE CLOSE...AND A FASTER SOLUTION WITH THE BOUNDARY LIKE THE
ECMWF MAY PUSH THE WINDS OVER 25 MPH. HUMIDITY VALUES STILL EXPECTED
TO DROP BELOW 25 PERCENT SOUTHWEST OF A STORM LAKE TO HURON
LINE...AND INTO THE TEENS WEST OF THE JAMES RIVER. SO DUE TO THE
VERY LOW HUMIDITY AND WIND UNCERTAINTY...WILL LEAVE THE FIRE
WEATHER WATCH AS IS...AND LET THE OVERNIGHT SHIFT VIEW 0Z MODEL
TRENDS WITH REGARDS TO WINDS.
EITHER WAY...IT WILL BE HOT AND DRY WEDNESDAY WITH MOSTLY SUNNY
SKIES. FOLLOWED A BLEND OF THE BIAS CORRECTED NAM AND ECMWF
SOLUTIONS FOR HIGHS...GENERALLY GIVING 90S AND 100S ACROSS THE AREA.
WARMEST TEMPERATURES SHOULD BE NEAR THE MISSOURI RIVER WEST OF THE
JAMES RIVER. THE LACK OF A STRONG WESTERLY COMPONENT OF THE WIND
COULD ACT TO LIMIT MIXING SOMEWHAT...ALTHOUGH POSSIBLE
SUPERADIABATIC HEATING SHOULD OFFSET ANY LACK OF MIXING. EVEN WITH
THE LOW DEWPOINTS...WE MAY HIT HEAT ADVISORY CRITERIA ALONG AND
WEST OF THE JAMES RIVER. SEEMS BORDERLINE IN MOST COUNTIES...WITH
ONLY BRULE AND GREGORY BEING TO BE A GOOD BET TO HIT IT. THUS FOR
COLLABORATION PURPOSES WILL HOLD OFF ON AN ADVISORY AND LET MIDNIGHT
SHIFT TAKE ANOTHER LOOK. /CHENARD
A BROAD MID LEVEL TROUGH MOVING ALONG THE CANADIAN BORDER WILL USHER
IN STRONG SOUTHWESTERLY FLOW WEDNESDAY NIGHT INTO THE BETTER PART OF
THURSDAY. THE RESULT WILL BE WELL MIXED AND BREEZY CONDITIONS WITH
VERY WARM TEMPERATURES. AHEAD OF THE BOUNDARY ON WEDNESDAY
NIGHT...COULD SEE A FEW NOCTURNAL HIGH BASED SHOWERS AND
THUNDERSTORMS ALONG OUR WESTERN BORDER. ANY PRECIPITATION THAT DOES
DEVELOP WOULD BE VERY LIGHT AND SHOULD DISSIPATE QUICKLY BY DAYBREAK
THURSDAY. LOWS WILL BE QUITE MILD...PARTICULARLY INTO SOUTH CENTRAL
SOUTH DAKOTA WHERE STRONG MIXING AND WARM AIR ADVECTION ON THE NOSE
OF THE LOW LEVEL JET SHOULD KEEP LOWS WELL INTO THE LOWER TO MID
70S.
FRONTAL BOUNDARY BEGINS ADVANCING EASTWARD INTO THE FORECAST AREA
EARLY THURSDAY...WHICH IS SLIGHTLY FASTER TIMING THAN PREVIOUS MODEL
RUNS. MODELS ARE IN REASONABLY GOOD AGREEMENT WITH THIS FASTER
TRACK...HOWEVER IT MAKES FOR A TRICKY TEMPERATURE FORECAST. THE WELL
MIXED CONDITIONS AHEAD OF THE FRONT WILL ALLOW FOR HIGHS FROM 100 TO
105 FOR AREAS THAT WILL SEE LONGEST MIXING...LIKELY SOUTH OF A SIOUX
FALLS TO LAKE ANDES LINE AND INTO FAR NORTHWEST IOWA. DEWPOINTS WILL
SIMILARLY PLUMMET IN THE AFTERNOON AND WILL RESULT IN MINIMUM RH
VALUES OF 15 TO 25 PERCENT FOR MUCH OF THE FORECAST AREA. WITH
ATTENDANT BREEZY WINDS...IT LOOKS LIKE ANOTHER POTENTIALLY EXTREME
FIRE WEATHER DAY. WENT AHEAD AND ISSUED A FIRE WEATHER WATCH FOR ALL
BUT THE FAR WESTERN ZONES WHICH WILL MISS OUT ON THE STRONGEST
SOUTHWEST WINDS WITH AN EARLIER FRONTAL PASSAGE.
THE EXTENDED RANGE WILL BE LARGELY DEPENDENT UPON THE TRACK OF THE
REMNANTS OF HURRICANE ISAAC. THE LATEST MODELS ARE IN SOMEWHAT
DECENT AGREEMENT WITH BRINGING THE REMNANTS NORTHWARD INTO THE
OZARKS AREA BY FRIDAY AFTERNOON. WITH UPPER LEVEL RIDGING IN PLACE
OVER THE NORTHERN PLAINS...SUBSIDENCE WILL BRING A DRY WEATHER ON
FRIDAY AND RELATIVELY LIGHT SOUTHEAST WINDS...BUT VERY LITTLE RELIEF
TO THE HEAT. HIGHS WILL REMAIN ABOVE NORMAL WITH READINGS IN THE 90S
HOWEVER HIGHER DEWPOINTS AND THE LIGHT WINDS WILL BRING SOME RELIEF
TO FIRE WEATHER CONCERNS.
MODELS BEGIN CURVING ISAAC A LITTLE MORE NORTHEASTWARD ON FRIDAY
NIGHT AND SATURDAY...WHICH BRINGS THE CENTER WHICH BRINGS THE CENTER
INTO THE MID MISSISSIPPI VALLEY. THE GFS IS SLIGHTLY WEST OF THE
ECMWF TRACK...WHILE THE GEM IS QUITE A BIT FURTHER EAST. IT STILL
LOOKS LIKE THIS SCENARIO WILL KEEP THE PRECIPITATION OUT OF OUR CWA
WITH ONLY SOME CLOUDS OR PERHAPS A STRAY SHOWER IN OUR FAR SOUTHEAST.
INTO EARLY NEXT WEEK...MODELS BEGIN DIVERGING QUITE A BIT WITH THE
POTENTIAL FOR A TROUGH MOVING INTO THE HIGH PLAINS AROUND THE
SATURDAY NIGHT THROUGH SUNDAY NIGHT TIME FRAME. THE GFS AND GEM ARE
MORE PRONOUNCED WITH THIS TROUGH WITH THE GFS BEING THE MOST
AGGRESSIVE. AT THE SAME TIME THE ECMWF WASHES OUT THE TROUGH WITH A
ZONAL FLOW PATTERN. OVERALL...NONE OF THE SOLUTIONS LOOK
PARTICULARLY IMPRESSIVE FOR PRECIPITATION CHANCES. WILL GO WITH
MENTION OF A SLIGHT CHANCE MAINLY IN OUR EAST.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED THROUGH 00Z THURSDAY. MAY SEE PATCHY FOG
WEST OF I29 09Z-13Z AND MAY SEE A FEW VISIBILITIES DROP TO 3 MILES
AT TIMES.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR IAZ300-301.
MN...FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR MNZ900.
NE...FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH
WEDNESDAY EVENING FOR NEZ249.
FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR NEZ249.
SD...FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH
WEDNESDAY EVENING FOR SDZ255-258.
FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR SDZ257-258.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
641 PM CDT TUE AUG 28 2012
.DISCUSSION.../ISSUED AT 345 PM CDT/
CURRENTLY SEEING STRONG SOUTHERLY WINDS OUT AHEAD OF AN APPROACHING
BOUNDARY. HAD A GUST TO 45 MPH HERE AT THE AIRPORT IN SIOUX
FALLS...BUT MOST LOCATIONS ARE GUSTING CLOSER TO 30 MPH. A DECENT
700 MB WAVE IS FORECAST TO MOVE ACROSS OUR NORTHEAST TONIGHT. THIS
WILL HELP DRAG A BOUNDARY ACROSS THE AREA LATE THIS AFTERNOON INTO
THE OVERNIGHT. WINDS WILL DIMINISH AFTER SUNSET...BUT WILL TEND TO
TAKE ON AN EASTERLY COMPONENT NORTH OF THIS BOUNDARY...WHILE A
SOUTHERLY BREEZE STAYS UP SOUTH OF INTERSTATE 90. BEST LOW AND MID
LEVEL FORCING STAYS EAST OF OUR AREA...AND WITH VERY LIMITED
MOISTURE...THINK WE STAY DRY. THIS IS SUPPORTED BY THE HRRR AND NAM
WHICH KEEP ELEVATED CONVECTION TO OUR EAST TONIGHT. LOWS SHOULD DROP
INTO THE LOW AND MID 60S NORTH OF THE BOUNDARY...WITH MID AND UPPER
60S TO THE SOUTH.
MODELS HANDLE THE BOUNDARY DIFFERENTLY ON WEDNESDAY. THE NAM IS
SLOWEST TO LIFT IT NORTH...WHILE THE GFS AND ECMWF ARE A BIT
QUICKER. NAM SEEMS TO HANDLE THESE MORE MESOSCALE BOUNDARIES
BETTER...SO TRENDED A BIT TOWARDS ITS SOLUTION. THIS WOULD RESULT
IN LIGHT EASTERLY WINDS TO BEGIN THE DAY...TURING SOUTHERLY AND
INCREASING LATE IN THE DAY. TIMING OF THE BOUNDARY AND WIND INCREASE
WILL BE IMPORTANT FOR FIRE WEATHER CONCERNS. FOR NOW...WINDS ARE
EXPECTED TO STAY BELOW RED FLAG CRITERIA ACROSS THE WHOLE AREA...BUT
IT WILL BE CLOSE...AND A FASTER SOLUTION WITH THE BOUNDARY LIKE THE
ECMWF MAY PUSH THE WINDS OVER 25 MPH. HUMIDITY VALUES STILL EXPECTED
TO DROP BELOW 25 PERCENT SOUTHWEST OF A STORM LAKE TO HURON
LINE...AND INTO THE TEENS WEST OF THE JAMES RIVER. SO DUE TO THE
VERY LOW HUMIDITY AND WIND UNCERTAINTY...WILL LEAVE THE FIRE
WEATHER WATCH AS IS...AND LET THE OVERNIGHT SHIFT VIEW 0Z MODEL
TRENDS WITH REGARDS TO WINDS.
EITHER WAY...IT WILL BE HOT AND DRY WEDNESDAY WITH MOSTLY SUNNY
SKIES. FOLLOWED A BLEND OF THE BIAS CORRECTED NAM AND ECMWF
SOLUTIONS FOR HIGHS...GENERALLY GIVING 90S AND 100S ACROSS THE AREA.
WARMEST TEMPERATURES SHOULD BE NEAR THE MISSOURI RIVER WEST OF THE
JAMES RIVER. THE LACK OF A STRONG WESTERLY COMPONENT OF THE WIND
COULD ACT TO LIMIT MIXING SOMEWHAT...ALTHOUGH POSSIBLE
SUPERADIABATIC HEATING SHOULD OFFSET ANY LACK OF MIXING. EVEN WITH
THE LOW DEWPOINTS...WE MAY HIT HEAT ADVISORY CRITERIA ALONG AND
WEST OF THE JAMES RIVER. SEEMS BORDERLINE IN MOST COUNTIES...WITH
ONLY BRULE AND GREGORY BEING TO BE A GOOD BET TO HIT IT. THUS FOR
COLLABORATION PURPOSES WILL HOLD OFF ON AN ADVISORY AND LET MIDNIGHT
SHIFT TAKE ANOTHER LOOK. /CHENARD
A BROAD MID LEVEL TROUGH MOVING ALONG THE CANADIAN BORDER WILL USHER
IN STRONG SOUTHWESTERLY FLOW WEDNESDAY NIGHT INTO THE BETTER PART OF
THURSDAY. THE RESULT WILL BE WELL MIXED AND BREEZY CONDITIONS WITH
VERY WARM TEMPERATURES. AHEAD OF THE BOUNDARY ON WEDNESDAY
NIGHT...COULD SEE A FEW NOCTURNAL HIGH BASED SHOWERS AND
THUNDERSTORMS ALONG OUR WESTERN BORDER. ANY PRECIPITATION THAT DOES
DEVELOP WOULD BE VERY LIGHT AND SHOULD DISSIPATE QUICKLY BY DAYBREAK
THURSDAY. LOWS WILL BE QUITE MILD...PARTICULARLY INTO SOUTH CENTRAL
SOUTH DAKOTA WHERE STRONG MIXING AND WARM AIR ADVECTION ON THE NOSE
OF THE LOW LEVEL JET SHOULD KEEP LOWS WELL INTO THE LOWER TO MID
70S.
FRONTAL BOUNDARY BEGINS ADVANCING EASTWARD INTO THE FORECAST AREA
EARLY THURSDAY...WHICH IS SLIGHTLY FASTER TIMING THAN PREVIOUS MODEL
RUNS. MODELS ARE IN REASONABLY GOOD AGREEMENT WITH THIS FASTER
TRACK...HOWEVER IT MAKES FOR A TRICKY TEMPERATURE FORECAST. THE WELL
MIXED CONDITIONS AHEAD OF THE FRONT WILL ALLOW FOR HIGHS FROM 100 TO
105 FOR AREAS THAT WILL SEE LONGEST MIXING...LIKELY SOUTH OF A SIOUX
FALLS TO LAKE ANDES LINE AND INTO FAR NORTHWEST IOWA. DEWPOINTS WILL
SIMILARLY PLUMMET IN THE AFTERNOON AND WILL RESULT IN MINIMUM RH
VALUES OF 15 TO 25 PERCENT FOR MUCH OF THE FORECAST AREA. WITH
ATTENDANT BREEZY WINDS...IT LOOKS LIKE ANOTHER POTENTIALLY EXTREME
FIRE WEATHER DAY. WENT AHEAD AND ISSUED A FIRE WEATHER WATCH FOR ALL
BUT THE FAR WESTERN ZONES WHICH WILL MISS OUT ON THE STRONGEST
SOUTHWEST WINDS WITH AN EARLIER FRONTAL PASSAGE.
THE EXTENDED RANGE WILL BE LARGELY DEPENDENT UPON THE TRACK OF THE
REMNANTS OF HURRICANE ISAAC. THE LATEST MODELS ARE IN SOMEWHAT
DECENT AGREEMENT WITH BRINGING THE REMNANTS NORTHWARD INTO THE
OZARKS AREA BY FRIDAY AFTERNOON. WITH UPPER LEVEL RIDGING IN PLACE
OVER THE NORTHERN PLAINS...SUBSIDENCE WILL BRING A DRY WEATHER ON
FRIDAY AND RELATIVELY LIGHT SOUTHEAST WINDS...BUT VERY LITTLE RELIEF
TO THE HEAT. HIGHS WILL REMAIN ABOVE NORMAL WITH READINGS IN THE 90S
HOWEVER HIGHER DEWPOINTS AND THE LIGHT WINDS WILL BRING SOME RELIEF
TO FIRE WEATHER CONCERNS.
MODELS BEGIN CURVING ISAAC A LITTLE MORE NORTHEASTWARD ON FRIDAY
NIGHT AND SATURDAY...WHICH BRINGS THE CENTER WHICH BRINGS THE CENTER
INTO THE MID MISSISSIPPI VALLEY. THE GFS IS SLIGHTLY WEST OF THE
ECMWF TRACK...WHILE THE GEM IS QUITE A BIT FURTHER EAST. IT STILL
LOOKS LIKE THIS SCENARIO WILL KEEP THE PRECIPITATION OUT OF OUR CWA
WITH ONLY SOME CLOUDS OR PERHAPS A STRAY SHOWER IN OUR FAR SOUTHEAST.
INTO EARLY NEXT WEEK...MODELS BEGIN DIVERGING QUITE A BIT WITH THE
POTENTIAL FOR A TROUGH MOVING INTO THE HIGH PLAINS AROUND THE
SATURDAY NIGHT THROUGH SUNDAY NIGHT TIME FRAME. THE GFS AND GEM ARE
MORE PRONOUNCED WITH THIS TROUGH WITH THE GFS BEING THE MOST
AGGRESSIVE. AT THE SAME TIME THE ECMWF WASHES OUT THE TROUGH WITH A
ZONAL FLOW PATTERN. OVERALL...NONE OF THE SOLUTIONS LOOK
PARTICULARLY IMPRESSIVE FOR PRECIPITATION CHANCES. WILL GO WITH
MENTION OF A SLIGHT CHANCE MAINLY IN OUR EAST.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED THROUGH 00Z THURSDAY. MAY SEE PATCHY FOG
WEST OF I29 09Z-13Z AND MAY SEE A FEW VISIBILITIES DROP TO 3 MILES
AT TIMES.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR IAZ300-301.
MN...FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR MNZ900.
NE...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 8 PM THIS EVENING
FOR NEZ249.
FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR NEZ249.
FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR NEZ249.
SD...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 8 PM THIS EVENING
FOR SDZ258.
FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR SDZ255-258.
FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR SDZ257-258.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
749 PM CDT TUE AUG 28 2012
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...THE AFTERNOON AND EVENING CONVECTION AROUND THE REGION
IS SLOWLY DYING OUT WITH THE LOSS OF THE AFTERNOON HEATING. ONE
LONE CELL PERSISTS OVER THE SOUTHEASTERN CORNER OF HIDALGO COUNTY
BUT SHOULD BE MOVING SOUTH OF THE RIVER OVER THE 30 TO 60 MINUTES.
SOME DEBRIS CLD COVER LEFT OVER FROM THIS CONV WILL LINGER ON FOR
A FEW MORE HOURS BUT EXPECT ONLY SCT MID TO HIGH LEVEL CLD DECKS
THROUGH THE NIGHT. A LIGHT NORTHERLY SURFACE FLOW WILL PREVAIL
THROUGHOUT THE MORNING HOURS TOMORROW DUE TO THE DISTANT INFLUENCE
OF ISAACS WIND FIELD. HOWEVER THIS NORTHERLY FLOW WILL BE WEAK
ENOUGH TO ALLOW THE AFTERNOON SEA BREEZE TO PUSH WEST POSSIBLY
FIRING AN ISOLD CONV CELL OR TWO. FOR NOW WILL NOT MENTION THIS
POTENTIAL IN THE CURRENT TAF SET AS THE COVERAGE WILL BE TOO
SPARSE FOR ANY SERIOUS IMPACTS ON THE LOWER RGV AIRPORTS. VFR
CEILINGS AND VSBYS WILL PREVAIL THROUGH THE NEXT 24 HOURS FOR THE
LOWER RGV AIRPORTS.
&&
.PREV DISCUSSION... /ISSUED 155 PM CDT TUE AUG 28 2012/
SHORT TERM.../TONIGHT THROUGH WEDNESDAY NIGHT/...A PACIFIC LOW OFF
THE NW US COAST MOVES INLAND WHILE THE MID LEVEL RIDGE CENTERED OVER
COLORADO BEGINS TO EDGE EASTWARD TOWARDS THE CENTRAL PLAINS. THE
RIDGE...SQUEEZED BETWEEN THE PACIFIC LOW AND LAND-FALLING ISAAC
BEGINS TO FLATTEN AND ELONGATE AS IT MOVES EAST. THE BIG STORY IN
THE SHORT TERM PERIOD REMAINS RECENTLY UPGRADED HURRICANE ISAAC. THE
LATEST NHC FORECAST HAS ISAAC MAKING LANDFALL ALONG THE SOUTHEASTERN
LOUISIANA COAST LATER THIS EVENING.
MEANWHILE THE RGV AND DEEP SOUTH TEXAS IS CAUGHT BETWEEN THE RIDGE
AND ISSAC...WHILE THE NORTHERN REACHES OF AN UPPER LEVEL
LOW...CENTERED OVER NORTHEAST MEXICO...MOVES WEST ACROSS THE LOWER
RGV. ISOLATED SHOWERS ASSOCIATED WITH A WEAK SHORTWAVE MOVING
SOUTH...HAVE STARTED TO MOVE INTO THE CWA FROM THE NORTH AND WILL
DISSIPATE BY TONIGHT. LIGHT AND VARIABLE WINDS CAN BE EXPECTED
OVERNIGHT WITH HIGH CIRRUS FROM ISAAC COVERING PORTIONS OF THE SKY.
WEDNESDAY...CIRRUS CLOUDS WILL PERSIST THROUGH THE PERIOD BUT SHOULD
NOT IMPACT TEMPERATURES TOO MUCH. AFTERNOON HIGHS WILL REMAIN TOASTY
ACROSS THE REGION WITH MANY LOCALES SEEING HIGHS NEAR OR ABOVE THE
CENTURY MARK. NORTHERLY FLOW WILL ALLOW DRIER AIR TO BEGIN TO FILTER
INTO THE REGION LATE IN THE PERIOD. MAINTAINED INHERITED POPS AS I
BELIEVE LATEST MODEL RUNS TO BE TOO GENEROUS WITH THE PRECIP.
LONG TERM.../THURSDAY THROUGH TUESDAY/...
BY THURSDAY HURRICANE ISAAC CENTER WILL BE LOCATED OVER THE NORTHERN
LOUISIANA WITH THE LATEST FORECAST FROM THE NHC. THIS SYSTEM IS
EXPECTED TO MOVE NORTH/NORTHWEST SPLITTING IN HALF THE UPPER HIGH
ACROSS THE CENTRAL PLAINS. DRY AIR ALOFT RAP AROUND THIS SYSTEM WILL
INFILTRATE INTO SOUTH TEXAS WITH A NORTHERLY FLOW. MINIMUM RH VALUES
WILL FALL BELOW 20 PERCENT ESPECIALLY ACROSS THE NORTHWEST PORTION
OF THE VALLEY THURSDAY. HOWEVER...LIGHT TO BREEZE SE WINDS WILL
LIMIT CRITICAL FIRE WEATHER CONDITIONS TO OCCUR. QUICKLY INTO
FRIDAY...SOUTHEAST FLOW RETURNS GRADUALLY ADVECTING LOW LEVEL
MOISTURE INTO THE CWA. A FEW ISOLATED SHOWERS CAN NOT BE RULED OUT
FROM CONVECTION DEBRI CLOUDS STREAMING ACROSS THE LOWER VALLEY
THROUGH THE REMAINDER OF THE WEEK. SUBSIDENCE WILL ALLOW FOR HIGH
TEMPERATURES TO REMAIN UP TO 5 DEGREES ABOVE NORMAL ACROSS THE CWA
WITH A FEW LOCALES IN THE WEST EVEN HIGHER. FRIDAY SE WINDS INCREASE
A BIT IN THE AFTERNOON TO MORE BREEZE TO WINDY CONDITIONS AS SURFACE
HIGH STRENGTHENS RIGHT OVER THE GULF.
FOR THE WEEKEND...BEST POSSIBILITY OF SEA BREEZE CONVECTION TO OCCUR
WILL LIKELY BE SATURDAY AND SUNDAY AFTERNOON AS MORE ABUNDANT
MOISTURE MOVES ALONG THE COASTAL COUNTIES. LEFT INHERITED 20 PERCENT
POPS FOR SATURDAY AND SUNDAY AS THIS SHOWERS MAY INCREASE AND MOVE
WESTWARD. TEMPERATURES WILL BE NEAR NORMAL FOR THE WEEKEND AS CLOUD
COVER AND RAINFALL BRING A SMALL BREAK TO THE TRIPLE DIGITS BY
COAST. LOWS WILL REMAIN IN THE UPPER 70S ACROSS THE VALLEY AND
DROPPING A FEW DEGREES SATURDAY NIGHT ESPECIALLY NORTHERN PORTION OF
THE CWA.
MARINE...TONIGHT THROUGH WEDNESDAY NIGHT...BUOY 42020 REPORTED
NORTHWEST WINDS AROUND 12 KNOTS WITH SEAS AT 3.6 FEET EARLY THIS
AFTERNOON. SEAS WILL GRADUALLY BUILD THIS EVENING THROUGH EARLY
WEDNESDAY AS LARGE SWELLS FROM HURRICANE ISAAC APPROACH FROM THE
EAST. SEAS MAY APPROACH SMALL CRAFT ADVISORY CONDITIONS DURING THE
OVERNIGHT HOURS TONIGHT. AS ISAAC MOVES INLAND AND SWELLS WILL
DECREASE SEAS WILL BEGIN TO SUBSIDE BY WEDNESDAY AFTERNOON.
THURSDAY THROUGH MONDAY...
SEAS WILL BE BETWEEN 3 TO 5 FEET FROM THURSDAY THROUGH SATURDAY AS
THE LARGE SCALE WIND FLOW OVER THE GULF IS DOMINATED BY HURRICANE
ISAAC AND IT CONTINUES TO INCREASE SWELLS OVER THE GULF. A FEW
SHOWERS AND THUNDERSTORMS ARE LIKELY OVER THE OFFSHORE WATERS. NW
FLOW SHIFTS TO THE SE AS HIGH PRESSURE OVER THE GULF TRIES TO
BUILD. EXPECT SE WINDS TO PICK UP FRIDAY AFTERNOON WITH A TIGHTER
GRADIENT ALONG THE COASTAL WATERS. BY SUNDAY CONDITIONS SHOULD
BEGIN TO IMPROVE WITH LOWER SEAS BETWEEN 2 TO 3 FEET NEAR AND
OFFSHORE.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 78 95 77 91 / 10 10 0 10
BROWNSVILLE 77 98 76 100 / 10 10 0 10
HARLINGEN 76 100 74 101 / 10 10 0 10
MCALLEN 79 101 77 103 / 20 10 0 10
RIO GRANDE CITY 78 101 78 105 / 20 10 0 10
SOUTH PADRE ISLAND 79 91 78 90 / 10 10 0 10
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...HIGH RIP CURRENT RISK THROUGH WEDNESDAY MORNING FOR TXZ251-256-
257.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
SHORT TERM...60
LONG TERM...63
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
631 PM CDT TUE AUG 28 2012
.SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT
245 PM CDT TUE AUG 28 2012
FORECAST FOCUS IN THE SHORT TERM PERIOD IS RAIN THREAT TONIGHT
INTO EARLY WEDNESDAY...AND THEN ON THE HOT TEMPERATURES TO END THE
WEEK. HOT...DRY...AND WINDY CONDITIONS POINTING TO DANGEROUS FIRE
POTENTIAL ON THURSDAY AS WELL.
19Z SURFACE ANALYSIS SHOWS A LOW PRESSURE CENTER OVER SD...WITH A
WARM FRONT REACHING EAST INTO SOUTHWEST MN AND NORTHEAST IA. WEAK
AREA OF CONVECTION MOVING ACROSS THE FORECAST AREA EARLY THIS
AFTERNOON...REMNANTS FROM A LARGER AREA OF STORMS THAT HAD
DEVELOPED OVERNIGHT ACROSS THE EASTERN DAKOTAS AND WESTERN MN.
CONDITIONS ACROSS THE PLAINS OF KS/NEB AS WELL AS WESTERN IA ARE
HOT AND BREEZY...AND THIS IS THE AIRMASS THAT WILL BE MOVING UP
INTO OUR REGION OVER THE NEXT FEW DAYS.
EXPECT THE CURRENT CONVECTION AREA TO CONTINUE A DIMINISHING TREND
AS WE MOVE TOWARD THE EVENING HOURS...AND ANY REMNANT LIFT FROM
WHATEVER CONVECTIVE VORTEX IS CONTAINED WITHIN DEPARTS THE AREA.
HOWEVER...DURING THE EVENING AND OVERNIGHT HOURS...ANTICIPATE THAT
THE LOW LEVEL WIND FLOW WILL INCREASE AND WILL PROVIDE SOME UPWARD
MOTION OVER THE WARM FRONT. EXPECT THERE TO BE ENOUGH LIFT ALONG
THE BAROCLINIC ZONE FOR ELEVATED CONVECTION TO DEVELOP. MANY OF
THE MESOSCALE FORECAST MODELS ARE POINTING TO SOME CONVECTION TO
DEVELOP TONIGHT. INCREASED RAIN CHANCES TONIGHT AS A RESULT.
SIMILAR TO WHAT HAPPENED UPSTREAM...EXPECT ANY CONVECTION THAT
DEVELOPS OVERNIGHT TO LINGER INTO EARLY WEDNESDAY OVER THE EASTERN
PART OF THE FORECAST AREA.
ATTENTION THEN SHIFTS TO A MAJOR WARM UP FOR WEDNESDAY AND
ESPECIALLY THURSDAY. AXIS OF WARMEST BUBBLE OF AIR SHIFTS INTO
EASTERN SD/NEB BY WEDNESDAY...WITH WARM ADVECTION SPREADING EAST
INTO OUR AREA AS WELL. THE WARMEST AIR WILL BE FOCUSED OVER
SOUTHERN MN/NORTHERN IA BY THURSDAY AFTERNOON. ECMWF/GFS 850MB
TEMPS RISE TO AROUND 25C...WITH NAM AS HIGH AS 29C. 700 MB TEMPS
RISE TO 13-15 DEG C RANGE. THESE WARM TEMPERATURE ANOMALIES ARE
SHOWING SOME 2.5 TO 3 STANDARD DEVIATIONS ABOVE NORMAL...POINTING
TO THE POTENTIAL FOR RECORD TEMPERATURES. HAVE MAINTAINED THE HOT
FORECAST...WITH HIGHS UP NEAR 100 POSSIBLE. SEE CLIMATE SECTION
BELOW FOR ADDITIONAL DETAILS. PRESSURE GRADIENT AHEAD OF A COLD
FRONT APPROACHING FROM THE NORTHWEST...AND HIGH PRESSURE OVER THE
OHIO VALLEY...WILL LEAD TO A BREEZY SOUTHWEST WIND...ADDING TO THE
HOT FEELING...AND HELPING TO MIX OUT THE LOWER ATMOSPHERE RESULTING
IN DRYING. FOR THESE REASONS...DANGEROUS FIRE POTENTIAL APPEARS
LIKELY...SO AFTER COORDINATION WITH SURROUNDING OFFICES AND STATE
FIRE OFFICIALS HAVE RAISED A FIRE WEATHER WATCH. SEE FIRE WEATHER
DISCUSSION BELOW FOR ADDITIONAL DETAILS.
FRONT EXPECTED TO DROP SOUTHWARD INTO SOUTHERN MN AND CENTRAL WI
BY THURSDAY NIGHT. HOWEVER WITH THE VERY DRY AIRMASS IN PLACE...NO
RAIN IS ANTICIPATED.
.LONG TERM...FRIDAY THROUGH MONDAY
245 PM CDT TUE AUG 28 2012
FRONT LOOKS TO LINGER OVER THE AREA ON FRIDAY. AIRMASS CONTINUES
TO BE VERY DRY LOCALLY...AND ANY INFLUX OF ADDITIONAL MOISTURE IS
DOUBTFUL WITH ISAAC KEEPING IT BOTTLED UP ALONG THE GULF COAST.
GFS WITH ITS MOIST BIAS INDICATING SOME POTENTIAL FOR SPOTTY
RAIN...BUT DISCOUNTING THAT FOR THE TIME BEING. FEED OF DRY AIR
CIRCULATING AROUND THE HIGH PRESSURE AREA OVER ONTARIO/GREAT LAKES
LOOKS TO KEEP THE AREA DRY UNTIL THE REMNANTS OF ISAAC CAN WORK
NORTH TOWARD US. LATEST THINKING IS THAT ISAAC WILL MOVE NORTH
INTO MO BY SATURDAY...SPREADING CLOUD AND RAIN POTENTIAL INTO IOWA
AND SOUTHERN WI. AT THIS TIME IT APPEARS THE TROPICAL REMNANTS
WILL BE SHUNTED EAST BEFORE REACHING OUR AREA...BUT WE WILL HAVE
TO MONITOR THAT OVER THE NEXT SEVERAL DAYS. LOOKING BACK TO THE
NORTHERN STREAM...A SHORT WAVE TROUGH AND ASSOCIATED COLD FRONT
WILL BE MOVING THROUGH THE AREA LATE SUNDAY INTO MONDAY...AND WILL
PROVIDE A THREAT FOR SHOWERS AND THUNDERSTORMS.
&&
.AVIATION...TONIGHT AND WEDNESDAY
630 PM CDT TUE AUG 28 2012
CONVECTION HAS EXITED THE AREA EARLY THIS EVENING WITH JUST A
SCATTERED TO BROKEN DECK OF CLOUDS IN THE 6K-10K FOOT RANGE. EXPECT
QUIET CONDITIONS THROUGH THE EARLY EVENING HOURS. HOWEVER...MODELS
SHOW LOW LEVEL JET/MOISTURE TRANSPORT INCREASES INTO SOUTHEAST
MINNESOTA BETWEEN 03Z-06Z. LAST SEVERAL RUNS OF THE RUC HAS BEEN
CONSISTENT IN SHOWING CONVECTION DEVELOPING ON THE NOSE OF THE
MOISTURE TRANSPORT LATE THIS EVENING AND THEN PUSHING SOUTHEAST
OVERNIGHT. PREVIOUS SET OF GRIDS HAD THIS WELL IN HAND AND KEPT
THE TIMING AND VCNTY SHRA AT BOTH TAF SITES. CEILINGS EXPECTED TO
REMAIN IN THE VFR CATEGORY...BUT CANNOT RULE OUT SOME MVFR
CONDITIONS WITHIN ANY STORMS THAT DEVELOP. SKIES WILL THEN CLEAR
LATER WEDNESDAY MORNING AS WARM FRONT SURGES NORTHWARD. SOUTH
WINDS WILL INCREASE TO 10 TO 12 KNOTS DURING THE AFTERNOON HOURS.
&&
.FIRE WEATHER...
245 PM CDT TUE AUG 28 2012
A WARM FRONT WILL LIFT THROUGH THE REGION TONIGHT...AND FOLLOWING
ITS PASSAGE...A SURGE OF HOT AND DRY AIR WILL OVERSPREAD THE ENTIRE
REGION WEDNESDAY THROUGH FRIDAY. HIGHS ON WEDNESDAY WILL TOP OUT IN
THE UPPER 80S ACROSS NORTH CENTRAL WISCONSIN TO LOWER 90S FOR MUCH
OF SOUTHERN MINNESOTA...WESTERN AND SOUTHERN WISCONSIN...AND
NORTHEAST IOWA. THURSDAY LOOKS TO BE A CRITICAL FIRE WEATHER
DAY...WITH HIGHS ACROSS THE REGION IN THE UPPER 90S TO AROUND 100
ALONG WITH SUSTAINED SOUTHWEST WINDS 15 TO 25 MPH WITH GUSTS UP TO
30 MPH. RELATIVE HUMIDITIES IN THE AFTERNOON WILL FALL TO BETWEEN 20
AND 25 PERCENT. A FIRE WEATHER WATCH IS IN EFFECT LATE THURSDAY
MORNING THROUGH EARLY THURSDAY EVENING FOR PORTIONS OF NORTHEAST
IOWA...SOUTHEAST MINNESOTA...AND WESTERN INTO CENTRAL WISCONSIN.
PLEASE SEE MKERWFARX AND MKEFWFARX FOR DETAILS CONCERNING THE FIRE
WEATHER FORECAST AS CONDITIONS WILL NEED TO BE CLOSELY MONITORED. ON
FRIDAY...THERE WILL BE SOME IMPROVING CONDITIONS WITH WINDS ON THE
LIGHTER SIDE...HOWEVER TEMPERATURES WILL STILL BE HOT WITH HIGHS IN
THE LOWER 90S.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
245 PM CDT TUE AUG 28 2012
WI...FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR WIZ017-029-032>034-041>044.
MN...FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR MNZ079-086>088-094>096.
IA...FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR IAZ008-009-018.
&&
$$
SHORT TERM...MW
LONG TERM...MW
AVIATION...RABERDING
FIRE WEATHER...ZT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
606 AM CDT MON AUG 27 2012
.SHORT TERM...TODAY THROUGH THURSDAY
359 AM CDT MON AUG 27 2012
AT 4 AM...WIDESPREAD DENSE FOG WAS BEING REPORTED ACROSS CENTRAL
AND SOUTHWEST WISCONSIN...AND PARTS OF NORTHEAST IOWA. THESE SAME
AREAS PICKED UP ANYWHERE FROM 0.75 TO 1.60 INCHES OF RAIN ON
SUNDAY...AND STAYED CLOUDY THROUGHOUT MUCH OF THE DAY. THIS AREA
HAS EXPANDED SOME DURING THE PAST HOUR...SO WILL HAVE TO EXPAND
THE DENSE FOG ADVISORY A BIT FURTHER NORTHWEST. JUST TO THE
NORTHWEST OF THE DENSE FOG AREA...THE PROFILER NETWORK INDICATES A
TROUGH MOVING SOUTHEAST THROUGH NORTHEAST IOWA...AND WESTERN AND
NORTHERN WISCONSIN. DEW POINTS HAVE BEEN FALLING IN THE WAKE OF
THIS TROUGH. THE MAIN QUESTION FOR THIS MORNING IS WHETHER THIS
WILL CAUSE THE DENSE FOG TO DISSIPATE FASTER THAN EXPECTED. IN THE
CASE OF VOLK FIELD AND BLACK RIVER FALLS...THE TEMPERATURES HAVE
BEEN FALLING RIGHT ALONG WITH THE DEW POINTS. WILL JUST HAVE TO
CONTINUE TO MONITOR THIS SITUATION THIS MORNING.
TODAY - THE SOUNDINGS SHOW PLENTY OF DRY AIR ALOFT. AS DIURNAL
MIXING OCCURS...SOME OF THIS DRY AIR WILL WORK ITS WAY TO THE
SURFACE. THE DIURNAL MIX DOWN /MIXING UP TO 825 MB/ TOOL INDICATES
THAT THE DEW POINTS WOULD FALL INTO THE LOWER AND MID 40S. SIMILAR
DEW POINTS WERE SEEN ACROSS THE EASTERN DAKOTAS AND NORTHWEST
MINNESOTA ON SUNDAY AFTERNOON. SINCE THERE IS A POSSIBILITY THAT
THE MIX DOWN DEW POINTS ARE A BIT TOO LOW...WENT WITH A 50-50
BLEND WITH THE NAM MOS DEW POINTS.
TONIGHT - THE MAIN QUESTION IS HOW WIDESPREAD THE VALLEY FOG WILL
END UP BEING. THE BUFKIT SOUNDINGS SHOW THAT THE WINDS WILL BE
5 KNOTS OR LESS UP TO 2.5 KM AND THE SKIES WILL REMAIN CLEAR.
HOWEVER WITH THE DEW POINTS DROPPING INTO 45 TO 52 DEGREE RANGE
THIS AFTERNOON...HOW MUCH OF A RECOVERY WILL THERE BE THIS EVENING
AND OVERNIGHT. THE NAM WHICH HAS A BETTER HANDLE ON THE DEW POINTS
TODAY...STILL SHOWS A 13 DEGREE TEMPERATURE/DEW POINT SPREAD AT
28.03Z...AND A 6 DEGREE SPREAD AT SUNRISE. ALSO WITH THE DRIER DEW
POINTS...THERE IS THE POTENTIAL THAT THE TEMPERATURES COULD END UP
BEING COOLER THAN EXPECTED WHICH COULD PROMOTE THE DEVELOPMENT OF
STEAM FOG OVER THE WARMER RIVERS WHICH COULD AID WITH THE
MOISTENING OF THE LOWEST PORTIONS OF THE BOUNDARY LAYER. AS A
RESULT...WENT WITH JUST AREAS OF VALLEY FOG FROM 27.08Z THROUGH
27.13Z. EVEN IF IT DOES DEVELOP...IT WILL LIKELY BE SHALLOW AND
WOULD BURN OFF QUICKLY ON TUESDAY MORNING.
TUESDAY AFTERNOON INTO TUESDAY NIGHT - THE MODELS INDICATE A
700-500 MB TROUGH MOVE THROUGH SOUTHERN MINNESOTA ON TUESDAY
AFTERNOON AND EVENING...AND NORTHERN AND EASTERN IOWA ON TUESDAY
NIGHT. THIS SYSTEM IS RIDING ON THE EASTERN EDGE OF AN UPPER LEVEL
RIDGE WHICH WILL BE BUILDING QUICKLY EAST INTO THE UPPER
MISSISSIPPI RIVER VALLEY. THE BUFKIT SOUNDINGS SUGGEST THAT THERE
WILL BE SOME MOISTENING BETWEEN 600 AND 500 MB. IN ADDITION...
THERE IS SOME ELEVATED CAPES BETWEEN 500 AND 750 J/KG.
HOWEVER...THERE IS ALSO PLENTY OF DRY AIR BELOW THESE CLOUD
BASES...SO THERE IS SOME QUESTION ON WHETHER THE PRECIPITATION
COULD EVEN MAKE IT TO THE GROUND. SINCE THE MODELS HAVE NOT BEEN
THAT ROBUST WITH THEIR PRECIPITATION CHANCES FOR THIS TIME
PERIOD...KEPT THE FORECAST DRY FOR NOW AND JUST ENHANCED THE CLOUD
COVER SOME.
ON WEDNESDAY AND THURSDAY...IT APPEARS THAT THE NAM/WRF IS MIXING
WAY TOO DEEP /UP TO 700 MB/ AND THE GFS IS NOT MIXING DEEP ENOUGH
/ONLY 925 MB/. WITH THE 850 MB GFS AND ECMWF TEMPERATURE ANOMALIES
RUNNING BETWEEN 2 AND 2.5 STANDARD DEVIATIONS ABOVE NORMAL...THIS
IS RATHER CRUCIAL ON HOW WARM THE AREA WILL ULTIMATELY GET.
DECIDED TO TAKE A COMPROMISE AND MIXED THE AREA UP TO 850 MB. THIS
WOULD RESULT IN HIGH TEMPERATURES IN THE LOWER AND MID 90S. THESE
TEMPERATURES ARE AT OR VERY CLOSE TO THE RECORD HIGHS ON THESE
DATES.
.LONG TERM...THURSDAY NIGHT THROUGH SUNDAY
359 AM CDT MON AUG 27 2012
THE MAIN QUESTIONS FOR THIS WEEKEND WILL BE WHERE THE REMNANTS OF
ISAAC WILL END UP AND WHETHER IT WILL INTERACT WITH A TROUGH
MOVING EAST ACROSS SOUTHERN CANADA. MANY OF THE OPERATIONAL MODELS
ARE BRINGING ISAAC NORTH INTO MISSOURI AND CENTRAL/NORTHERN
ILLINOIS. WITH THE MODELS CONTINUE TO SHIFT THE TRACK OF THIS
SYSTEM FURTHER WEST...THE POTENTIAL OF THIS SYSTEM MOVING SOMEWHERE
THROUGH THE MID MISSISSIPPI RIVER VALLEY LOOKS BETTER AND BETTER.
LOOKING AT THE HISTORIC TRACKS OF THE SYSTEMS /25 TOTAL/ THAT
MOVED THROUGH CENTRAL AND NORTHERN ILLINOIS...A MAJORITY OF THEM
EITHER MADE LAND FALL EITHER IN THE MISSISSIPPI RIVER DELTA OR
EASTERN TEXAS. THE LAST TIME THIS OCCURRED WAS THE REMNANTS OF
HURRICANES GUSTAV AND IKE IN 2008. THE NATIONAL HURRICANE CENTER
TRACK IS SOMEWHERE IN THE MISSISSIPPI RIVER DELTA.
A FEW OF THE GFS ENSEMBLE MEMBERS ARE ACTUALLY FASTER WITH THE
CANADIAN SHORT WAVE AND IT HAS THE PRECIPITATION MOVING INTO
NORTHEAST IOWA AND SOUTHERN WISCONSIN ON SATURDAY AFTERNOON.
MEANWHILE THE OPERATIONAL GFS AND ECMWF WOULD SUGGEST THAT THE
PRECIPITATION ASSOCIATED WITH ISAAC WOULD REMAIN TO OUR SOUTH AND
EAST. HOWEVER THESE MODELS DO INDICATE THAT THERE MAY BE SOME
PRECIPITATION ASSOCIATED WITH A COLD FRONT MOVING ACROSS
MINNESOTA. THE GFS ACTUALLY INCREASES ITS PRECIPITABLE WATER UP TO
1.80 INCHES ALONG THIS FRONT. IS THIS AN INDICATION OF A POSSIBLE
PREDECESSOR RAIN EVENT. STUDIES SHOWN THAT THERE IS A VERY HEAVY
RAIN POTENTIAL WELL AHEAD OF RECURVING TROPICAL CYCLONES. SINCE
THERE IS STILL MUCH UNCERTAINTY ON WHERE ISAAC WILL MAKE
LANDFALL...WHERE IT WILL ULTIMATELY TRACK ONCE INLAND...AND THAT
THE MODELS HAVE BEEN KEEPING THE AREA DRY...JUST KEPT THE AREA DRY
THROUGHOUT THIS ENTIRE TIME PERIOD.
&&
.AVIATION...TODAY AND TONIGHT
606 AM CDT MON AUG 27 2012
THE ONLY CONCERN THROUGH THE PERIOD IS WITH FOG AT KLSE. EXPECTING
THE VALLEY FOG TO BEGIN LIFTING AROUND 13Z AND SHOULD COMPLETELY
DISSIPATE BETWEEN 14 AND 15Z. THE CONCERN THEN BECOMES WHETHER THE
FOG WILL REFORM TONIGHT. THE HIGH WILL STILL BE OVER THE AREA FOR
CLEAR SKIES AND WINDS LESS THAN 10 KNOTS UP THROUGH 5K FEET. THE
QUESTION MARK FOR THE FOG IS WHETHER SATURATION WILL OCCUR OR NOT.
THE 27.06Z NAM BUFKIT SOUNDING SUGGESTS DEEP MIXING WILL OCCUR
THIS AFTERNOON WITH TEMP/DEW POINT SPREAD OF 30+ DEGREES POSSIBLE
AND THE RECOVERY THAT OCCURS DURING THE EVENING AND OVERNIGHT WILL
NOT BE ENOUGH TO ALLOW SATURATION TO OCCUR. THE 27.00Z GFS
SOUNDING ALSO SUGGEST SATURATION DOES NOT OCCUR TONIGHT.
HOWEVER...THE 27.09Z RAP SUGGEST THAT THE TEMP/DEW POINT SPREAD
WILL BE ON THE VERGE OF BEING FAVORABLE THIS EVENING WITH A 7
DEGREE TEMP/DEW POINT SPREAD AT 03Z. NOT SURE THIS IS REALISTIC
THOUGH AS THE RAP DOES NOT INDICATE MUCH MIXING DURING THE
AFTERNOON HOLDING THE DEW POINTS UP IN THE 60S.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
348 AM CDT MON AUG 27 2012
WI...DENSE FOG ADVISORY UNTIL 8 AM CDT THIS MORNING FOR WIZ034-
041>044-053>055-061.
MN...DENSE FOG ADVISORY UNTIL 8 AM CDT THIS MORNING FOR MNZ096.
IA...DENSE FOG ADVISORY UNTIL 8 AM CDT THIS MORNING FOR IAZ010-011-
029-030.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1200 AM CDT MON AUG 27 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
1200 AM CDT MON AUG 27 2012
MIDNIGHT UPDATE...WITH FOG EXPANDING ACROSS SOUTHWEST WISCONSIN AND
FAR NORTHEAST IOWA...WHERE IT RAINED DECENTLY YESTERDAY AND CLEARED
OUT LATE...WILL BE ISSUING A DENSE FOG ADVISORY.
DRY CONDITIONS EXPECTED THROUGH MID WEEK WITH THE MAIN FORECAST
FOCUS BEING ON TEMPERATURES AND FOG.
CURRENTLY...A SYSTEM THAT BROUGHT RAIN AND CLOUD COVER TO THE
REGION TODAY IS SLOWLY RETREATING EAST INTO THE GREAT LAKES. RAIN
HAS COME TO AN END WITH THE UPPER LEVEL TROUGH PUSHING INTO EASTERN
WISCONSIN. THE QUESTION FOR TONIGHT IS WITH HOW FAST THE CLOUDS
CLEAR OUT AND WHETHER ANY FOG WILL DEVELOP AS IT DID ACROSS
WESTERN MINNESOTA/IOWA THIS MORNING. THE 26.18Z RAP MOISTURE
FIELDS SHOW THE DEEPER MOISTURE FIELD ASSOCIATED WITH THE TROUGH
AND RAINFALL SHIFTING EAST BY THIS EVENING. ALSO...THE STRATUS
FIELD ALONG THE WESTERN SIDE OF THE TROUGH HAS BECOME MUCH MORE
CELLULAR AND SHOULD THIN OUT THIS EVENING AND LEAD TO CLEAR SKIES
THOUGH OUT THE REGION OVERNIGHT.
WITH THESE CLEARING SKIES...LIGHT WINDS...AND A RIDGE AXIS OF
HIGH PRESSURE PUSHING IN...WILL LIKELY SEE SOME FOG FORM ACROSS
THE REGION. THE BEST CHANCES FOR WIDESPREAD AND POSSIBLY DENSE FOG
WILL BE ACROSS SOUTHERN WISCONSIN INTO EASTERN IOWA WHERE THE RAIN
AND CLOUDS HOLD ON LONGER TODAY BEFORE CLEARING OUT LATER TONIGHT.
SHOULD ALSO SEE FOG FORM IN THE MISSISSIPPI AND WISCONSIN RIVER
VALLEYS TONIGHT AS WELL THOUGH HOW WIDESPREAD IT BECOMES WILL BE
DEPENDENT UPON THE LOW LEVEL WIND FIELDS. SEE THE LATEST AVIATION
AFD FOR FURTHER/UPDATED DETAILS ON THE POTENTIAL FOR THIS VALLEY
FOG.
GOING INTO THE EARLY TO MID PORTIONS OF THE WEEK...WARMER AIR WILL
SLOWLY ADVECT INTO THE REGION FROM THE WEST AS A SURFACE RIDGE OF
HIGH PRESSURE SETTLES OVER THE UPPER MISSISSIPPI RIVER VALLEY AND
AN UPPER LEVEL RIDGE BUILDS ACROSS THE ROCKIES. WILL HAVE TO WATCH
A WARM FRONT THAT SURGES NORTHWARD TUESDAY INTO WEDNESDAY AS THE
26.12Z NAM AND GFS TRY TO PRODUCE SOME ELEVATED CONVECTION ACROSS
MINNESOTA WESTERN WISCONSIN. CONFIDENCE IS NOT HIGH THAT THIS
CONVECTION WILL OCCUR GIVEN THE DRY LOW LEVELS AND BETTER MOISTURE
TRANSPORT OFF TO THE WEST...SO HAVE KEPT THE FORECAST DRY THROUGH
THIS PERIOD BUT HAVE PUT SOME SLIGHTLY HIGHER CLOUD COVER IN OVER
THIS TIME FRAME. OTHERWISE EXPECT TEMPERATURES TO SLOWLY REBOUND
GOING INTO MID WEEK AS WARMER AIR SPILLS TO THE EAST AS THE
WESTERN RIDGE BUILDS EASTWARD INTO THE REGION WITH 850MB
TEMPERATURES CLIMBING FROM AROUND +13C ON MONDAY TO AROUND +23C BY
WEDNESDAY.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
227 PM CDT SUN AUG 26 2012
THE MAIN STORY FOR THE LATER PART OF THE WEEK WITH WITH THE WARM
AIR MASS THAT WILL TAKE OVER THE UPPER MISSISSIPPI RIVER VALLEY
REGION. AFTER THE WARM FRONT LIFTS NORTH OF THE REGION ON
WEDNESDAY...STRONG SOUTHERLY LOW LEVEL FLOW WILL KICK IN FROM THE
SOUTHERN PLAINS UP INTO THE GREAT LAKES AND NORTHERN PLAINS. THE
BUILDING RIDGE ACROSS THE ROCKIES WILL BEGIN TO SHIFT TO THE EAST
WEDNESDAY NIGHT INTO THURSDAY WITH THURSDAY LOOKING LIKE THE
WARMEST DAY OF THE WEEK. 850MB TEMPERATURE ANOMALIES FROM THE
26.12Z GFS AND ECMWF SHOW THAT THE +23C 850MB TEMPERATURES ARE
ABOUT 2 STANDARD DEVIATIONS ABOVE THE NORM...WHICH WOULD PUSH
RECORD HIGHS IN THE MID 90S. WITH THE WARMER AIR GRADUALLY
GETTING INTO THE REGION...HAVE GONE WITH A GRADUAL WARMING TREND
WITH THE NEAR RECORD HIGHS FOR THURSDAY. PRECIPITATION CHANCES
WILL BE MINIMAL UNTIL MAYBE NEXT WEEKEND AS A COLD FRONT DROPS
DOWN THROUGH LAKE SUPERIOR. THE 26.12Z GFS IS MORE PROGRESSIVE
WITH BRINGING THE FRONT SOUTH THROUGH THE REGION WHILE THE 26.12Z
ECMWF KEEPS THE FRONT TO THE NORTH. THE 26.12Z GFS IS ALSO ON THE
WESTERN TRACK WITH THE REMNANTS OF ISAAC COMING NORTH ALONG THE
MISSISSIPPI WHILE THE 26.12Z KEEPS IT WELL TO THE SOUTHEAST.
CONFIDENCE IS NOT VERY HIGH WITH WHERE THIS FEATURE WILL
TRACK...BUT THERE IS A BETTER CHANCE THAT IT WILL STAY TO THE
SOUTHEAST AND NOT COME INTO THE REGION. THEREFORE...HAVE KEPT THE
FORECAST MAINLY DRY THROUGH NEXT WEEKEND.
&&
.AVIATION...THROUGH 06Z TUESDAY
1200 AM CDT MON AUG 27 2012
RADIATION GROUND FOG HAS DEVELOPED AT KLSE...DUE TO LIGHT WINDS AND
LINGERING HIGH SURFACE DEWPOINTS. VISIBILITIES HAVE BEEN BOUNCING
BETWEEN MVFR AND VLIFR. ANTICIPATING TO THIS CONTINUE THE NEXT 2 TO
4 HOURS...OR PERHAPS THROUGH THE REST OF THE NIGHT. SHOULD VALLEY
FOG FORM...VLIFR CONDITIONS WILL HOLD IN PLACE. STILL SOMEWHAT
QUESTIONABLE ABOUT VALLEY FOG...GIVEN A TROUGH EXPECTED TO COME
THROUGH AROUND 08Z AND ALLOW NORTHWEST WINDS TO PICK UP.
STILL...COOLING TEMPERATURES SHOULD KEEP RADIATION FOG GOING. AS
SUCH...WENT MORE PESSIMISTIC WITH THE FORECAST FOR KLSE...STAYING
VLIFR UNTIL 13Z. ONCE THE SUN COMES UP AND STARTS MIXING...KLSE
SHOULD QUICKLY GO TO VFR BY 14Z. VFR CONDITIONS ARE THEN EXPECTED
THROUGH 06Z TUESDAY AS FURTHER DRYING TAKES PLACE.
AT KRST...A STEADY 4-6 KT NORTHWEST BREEZE BRINGING IN DRIER AIR
WILL KEEP VFR CONDITIONS THERE THROUGH THE PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
1159 PM CDT SUN AUG 26 2012
WI...DENSE FOG ADVISORY UNTIL 8 AM CDT MONDAY FOR WIZ042>044-053>055-
061.
MN...NONE.
IA...DENSE FOG ADVISORY UNTIL 8 AM CDT MONDAY FOR IAZ011-029-030.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1041 PM MDT TUE AUG 28 2012
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 214 PM MDT TUE AUG 28 2012
SATELLITE IMAGERY AND RUC ANALYSIS SHOW A SMALL VORT MAX OVER THE
NORTHERN PORTION OF THE UNCOMPAHGRE PLATEAU...BETWEEN GATEWAY AND
GRAND JUNCTION...MOVING NE AND ENHANCING CONVECTION OVER THE
BOOKCLIFFS AND TAVAPUTS PLATEAUS IN EASTERN UT AND WESTERN CO.
THIS FEATURE WILL CONTINUE MOVING NE AND PROVIDE A MINOR FOCUS FOR
CONVECTIVE DEVELOPMENT AS IT DOES SO. THUS FAR...SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED ONLY OVER THE MOUNTAINS AS EXPECTED.
LATE THIS AFTERNOON AND EARLY EVENING...OUTFLOWS SHOULD BEGIN TO
PUSH SOME CONVECTION INTO THE VALLEYS OR PROVIDE THE LIFT SO
THUNDERSTORMS CAN DEVELOP OVER THE LOWER ELEVATIONS. AFTER SUNSET
IT ALL SHOULD BEGIN DISSIPATING.
NOT MUCH CHANGE PREDICTED THROUGH WEDNESDAY NIGHT. THE RIDGE WILL
REMAIN CENTERED OVER COLORADO WITH NO STRONG MONSOONAL TAP
INDICATED. MOISTURE WILL CONTINUE TO RECYCLE BENEATH THE RIDGE...
PRODUCING A GRADUAL INCREASE IN DIURNAL SHOWERS AND THUNDERSTORMS
...MAINLY OVER THE MOUNTAINS. MAX AND MIN TEMPS WILL SHOW LITTLE
CHANGE.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 214 PM MDT TUE AUG 28 2012
HIGH PRESSURE THAT HAS BEEN CENTERED OVER THE CENTRAL ROCKIES JUMPS
TO THE EASTERN USA THU AS IT GETS PINCHED BETWEEN THE REMNANTS OF
HURRICANE ISAAC AND A LARGE TROUGH OVER THE PAC NW. HOWEVER...
LITTLE CHANGE IN OUR SENSIBLE WEATHER IS EXPECTED THU-SAT WITH A
CONTINUATION OF MAINLY AFTERNOON/EARLY EVENING SHOWERS AND
THUNDERSTORMS EACH DAY. WHILE MOISTURE ASSOCIATED WITH ISAAC WILL
REMAIN FAR TO OUR EAST...LINGERING MONSOONAL MOISTURE AROUND 3/4
INCH OR BETTER OF PRECIPITABLE WATER MEANS LOCALLY HEAVY RAIN WILL
STILL BE POSSIBLE.
AS SHORTWAVES EJECT FROM THE PAC NW MEAN TROUGH AND ACROSS THE
NORTHERN ROCKIES...THE 12Z GFS SHOWS A DRIER WESTERLY FLOW BECOMING
DOMINANT BY SUNDAY. 12Z ECMWF IS SLOWER WITH ANY DRYING BUT SHOWS
THE SAME TREND. THIS SHOULD LEAD TO LESS THUNDERSTORM ACTIVITY
SUNDAY THROUGH TUESDAY. MODELS SHOW THE RIDGE BUILDING BACK INTO
AZ/NM BY TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1038 PM MDT TUE AUG 28 2012
VFR CONDITIONS WILL PREVAIL THROUGH MIDDAY WEDNESDAY. AFTER 18Z
WEDNESDAY...ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL
DEVELOP OVER THE MOUNTAINS. A FEW OF THESE WILL DRIFT OVER THE
VALLEYS BETWEEN 22Z WEDNESDAY AND 03Z THURSDAY. GUSTY WINDS AND
HEAVY RAINFALL WILL ACCOMPANY THE STORMS...ALONG WITH BRIEF MVFR
CIGS. EXPECT LOCAL MOUNTAIN OBSCURATIONS AS WELL.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...CC
LONG TERM...JAD
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
349 AM EDT WED AUG 29 2012
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO BUILD INTO OUR REGION TODAY AND
TONIGHT BEFORE MOVING TO OUR SOUTHEAST LATE ON THURSDAY. A BACKDOOR
COLD FRONT PUSHES THROUGH ON SATURDAY AND OFF TO OUR SOUTH BY SUNDAY
WITH HIGH PRESSURE OVERHEAD. WEAK LOW PRESSURE, POSSIBLY TIED TO THE
REMNANTS OF HURRICANE ISAAC, MOVES IN FROM THE WEST LATE MONDAY INTO
TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
JUST SOME PATCHY ALTOCUMULUS EARLY THIS MORNING AS A WEAK COLD FRONT
DROPS SOUTH THROUGH THE AREA. THE MAIN PATCH OF ALTOCUMULUS WILL
AFFECT PHILADELPHIA METRO AND NEARBY CENTRAL NEW JERSEY THROUGH
SUNRISE. LOWER CLOUDS ARE COMING OFF LAKES ERIE AND ONTARIO. IT IS
POSSIBLE THAT THE CLOUDS FROM ERIE COULD CLIP THE NORTHERN LEHIGH
VALLEY AND SOUTHERN POCONOS FOR A TIME LATER THIS MORNING.
OTHERWISE...THE COLUMN IN THE NEW AIRMASS COULD BE DRY ENOUGH TO
PRECLUDE MUCH IN THE WAY OF CLOUDS FOR MOST OF THE AREA TODAY. A
SHORT WAVE DROPPING THROUGH THE GREAT LAKES EARLY THIS MORNING LOOKS
TO WEAKEN AS IT CROSSES NORTHERN AREAS THIS AFTERNOON. THE PASSING
SHORT WAVE COULD RESULT IN SOME HIGH BASED STRATOCUMULUS ACROSS THE
SOUTHERN POCONOS AND NORTHWEST NEW JERSEY AS CONVECTIVE TEMPERATURES
ARE APPROACHED.
AS THE SURFACE FRONT PASSES THIS MORNING...THERE WILL BE A PERIOD OF
TIME FROM SUNRISE THROUGH LATE THIS MORNING WHEN NORTHERLY WINDS
COULD GUST NEAR 20 MPH ALONG THE NEW JERSEY COAST. THE GRADIENT FLOW
WILL GRADUALLY BACK OFF THIS AFTERNOON...AND COULD EVEN BACK OFF
ENOUGH TO ALLOW LATE SEA AND BAY BREEZES TO DEVELOP.
WHILE THE AIRMASS IS IN TRANSITION WITH LOW LEVEL COLD AIR ADVECTION
ENDING THIS MORNING...850 MB TEMPERATURES WOULD SUPPORT HIGHS IN THE
MID 70S TO LOWER 80S. THE HIGHER END OF THE RANGE SHOULD BE REALIZED
OUTSIDE OF THE INFLUENCE OF THE TERRAIN...AND IS CLOSER TO THE
COOLER GFS MOS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
0000 UTC NAM MODEL SOUNDINGS CONTINUE TO INDICATE STRATOCUMULUS
LEVEL MOISTURE ACROSS SOUTHEAST PENNSYLVANIA...NORTHEAST MARYLAND...
DELAWARE AND SOUTHWEST NEW JERSEY AFTER 0600 UTC THURSDAY. THE
MOISTURE IS PRESUMABLY CAUGHT UNDER THE INVERSION BEHIND THE FRONT.
THE LOW LEVEL FLOW DOES NOT APPEAR TO BACK ENOUGH TO ALLOW RETURN
FLOW TONIGHT.
BASED ON THE ABOVE...THE MOISTURE LOOKS OVERDONE AND WHILE THERE MAY
BE SOME STRATOCUMULUS...MAINLY CLEAR SKIES ARE EXPECTED IN THE
ABOVEMENTIONED AREAS. ELSEWHERE...WITH MID LEVEL RIDGING START TO
BUILD IN FROM THE WEST...SKIES SHOULD BE CLEAR OR MAINLY CLEAR.
THERE COULD BE ENOUGH OF A LOW LEVEL FLOW TO KEEP WINDS JUST STRONG
ENOUGH TO PRECLUDE MORE THAN PATCHY FOG. PATCHY FOG WILL BE INCLUDED
IN THE FORECAST...BUT THE COVERAGE MAY NEED TO BE REFINED LATER
TODAY. FOR THE MOST PART...LOWS WERE BASED ON A MOS BLEND...WITH A
NOD TOO COOLER TEMPERATURES IN PLACES LIKE THE NEW JERSEY PINE
BARRENS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
5-WAVE MODEL GUIDANCE SHOWS RIDGING ACROSS MUCH OF THE EASTERN
UNITED STATES WITH A TRANSITION TO MEAN TROUGHING BY LATE IN THE
WEEKEND.
A MAJORITY OF THE LONGTERM PERIOD LOOKS DRY AND STABLE AS MID-LEVEL
RIDGING SITUATED ACROSS THE MID-WEST PIVOTS TOWARDS THE EAST. THE
DOME OF SURFACE HIGH PRESSURE WILL ALLOW TEMPERATURES TO CLIMB ABOVE
AVERAGE BY THURSDAY AND FRIDAY AND A RETURN TO MORE HUMID CONDITIONS
COMMENCES BY FRIDAY. THE RETURN FLOW SETTING UP BY FRIDAY MORNING
MAY ALSO INTRODUCE ENOUGH LOW-LEVEL MOISTURE BENEATH THE NOCTURNAL
INVERSION TO PRODUCE STRATUS ACROSS THE DELMARVA ZONES...SKY GRIDS
WERE ADJUSTED UPWARDS.
NUMERICAL GUIDANCE CONTINUES TO SHOW A BACK DOOR COLD FRONT PUNCHING
THROUGH THE REGION DURING THE DAY SATURDAY AND SETTLING TO OUR
SOUTH BY SUNDAY. CURRENT PROGNOSIS IS THIS MORE OF A WIND SHIFT WITH VERY
LITTLE IN THE WAY OF MOISTURE SO KEPT SATURDAY DRY. INCREASED
CHANCES FOR SHOWERS AND THUNDERSTORMS ON SUNDAY, EVEN WITH SURFACE
HIGH PRESSURE NEARBY. THIS IS ALL DUE TO THE PROXIMITY OF THE
FRONTAL BOUNDARY TO OUR SOUTH AND A MORE PROGRESSIVE MID-LEVEL
FLOW WHICH STREAMS ENERGY ACROSS OUR REGION DURING THE DAY.
THE QUESTION ON EVERY ONES MIND IS HOW WILL THE REMNANTS OF
HURRICANE ISAAC AFFECT OUR REGION, AND WHEN. MODELS STILL SHOW A
BULK OF THE MOISTURE REMAINING TO OUR WEST BY MONDAY, BUT AS THE
REMNANT LOW MOVES INTO THE OHIO VALLEY ON MONDAY A WARM FRONT IS
LIFTED TOWARDS THE REGION ALLOWING THE TROPICAL MOISTURE TO MOVE
INTO OUR NECK OF THE WOODS EARLY TUESDAY MORNING.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS CONTINUE EARLY THIS MORNING...WITH JUST SOME MID
LEVEL CLOUDINESS ACROSS PORTIONS OF SOUTHEAST PENNSYLVANIA. AS A
COLD FRONT DRIFTS SOUTH OF THE AREA...SURFACE WINDS WILL SHIFT TO
THE NORTH...AND INCREASE TO NEAR 10 KNOTS BY DAYBREAK AT KPHL AND
KACY. THE LIGHT GRADIENT SHOULD PREVENT ANY PATCHY MVFR FOG FROM
DEVELOPING.
DURING THE DAY...VFR CONDITIONS ARE EXPECTED. THE NORTHERLY FLOW
WILL PRODUCE WINDS NEAR 10 KNOTS THIS MORNING...AND GUSTS ARE
POSSIBLE AT KACY THROUGH ABOUT 1500 UTC. DURING THE AFTERNOON...
WINDS WILL BACK TO THE NORTHWEST AND PROBABLY DROP BELOW 10 KNOTS.
VFR CONDITIONS ARE EXPECTED TONIGHT. THERE MAY BE ENOUGH OF A LIGHT
NORTHWEST FLOW TO PRECLUDE MUCH IN THE WAY OF MVFR/IFR FOG TONIGHT.
THIS WILL BE ADDRESSED MORE FOR THE 1200 UTC FORECAST ISSUANCE.
OUTLOOK...
THURSDAY THROUGH SUNDAY...VFR CONDITIONS EXPECTED WITH GENERALLY A
SOUTHERLY WIND. COULD SEE ISOLATED SHOWERS AND THUNDERSTORMS
DURING THE DAY ON SUNDAY.
&&
.MARINE...
SURFACE WINDS ARE IN THE PROCESS OF SHIFTING TO THE NORTH BEHIND A
WEAK COLD FRONT EARLY THIS MORNING. THUS FAR...WIND GUSTS HAVE
REMAINED BELOW 15 KNOTS...BUT AIRCRAFT SOUNDINGS JUST TO THE NORTH
OF THE WATERS SHOW WINDS NEAR 20 KNOTS AT 1800 FEET. THESE WINDS
SHOULD MIX DOWN BETWEEN 0900 AND 1500 UTC...AS THE LOW LEVEL PUSH OF
COOL AIR OVER THE RELATIVELY WARM WATER SHOULD RESULT IN EFFICIENT
MOMENTUM TRANSFER.
THE LATEST HRRR AND RAP OUTPUT SHOWS THE POTENTIAL FOR 25 KNOT GUSTS
ACROSS THE SOUTHERN OCEAN WATERS AND LOWER DELAWARE BAY BETWEEN 0900
AND 1100 UTC. NO HEADLINES YET AS THERE IS NOT ENOUGH CONFIDENCE IN
OCCURRENCE...BUT TRENDS WILL BE WATCHED FOR GUSTS AS WE APPROACH
1000 UTC. IT WOULD ALSO APPEAR THAT THE NORTHERLY FETCH WILL NOT BE
IN PLACE LONG ENOUGH TO PRODUCE 5 FOOT SEAS ACROSS THE SOUTHERN
OCEAN WATERS THIS MORNING.
WHILE THE PRESSURE GRADIENT REMAINS IN PLACE INTO THE EARLY TO MID
AFTERNOON HOURS...THE GUSTINESS SHOULD DROP OFF AS THE LOW LEVEL
PUSH EXITS TO THE SOUTH. IN FACT...THE GRADIENT COULD DROP OFF
ENOUGH TO ALLOW LOCAL SEA AND BAY BREEZES TO DEVELOP LATE THIS
AFTERNOON...BUT CONFIDENCE IN THIS OCCURRING RIGHT NOW IS LOW.
IF SEA AND BAY BREEZES DO DEVELOP...THEY SHOULD DISSIPATE BY MID
EVENING...AND WINDS WILL SNAP BACK TO SYNOPTIC DIRECTIONS. WHILE THE
PRESSURE GRADIENT IS NOT THAT STRONG...THERE COULD BE ENOUGH FLOW
FOR A LIGHT BUT PERSISTENT NORTH TO NORTHWEST FLOW OVERNIGHT.
OUTLOOK...
SUB-ADVISORY CONDITIONS ARE EXPECTED ACROSS OUR WATERS DURING THE
OUTLOOK PERIOD. WINDS WILL TURN MORE TOWARDS THE SOUTH BY FRIDAY
AS HIGH PRESSURE MOVES FURTHER TO OUR SOUTH AND EAST DURING THE
DAY. COLD FRONT WILL SWING THROUGH DURING THE DAY SATURDAY WITH
WINDS TURNING TOWARDS THE WEST AND COULD BECOME GUSTY AT
TIMES...SUB-20 KNOTS EXPECTED. SEAS WILL REMAIN AROUND 3 FEET
THROUGH SATURDAY AND MAY INCREASE TO 4 FEET ON SUNDAY.
&&
.RIP CURRENTS...
THE WAVE PERIOD IS EXPECTED TO INCREASE TO AROUND 10 SECONDS LATER
THIS MORNING AND THIS AFTERNOON. THIS COMBINED WITH THE ALONGSHORE
NORTHERLY FLOW OF 10 TO 15 MPH WILL LIKELY RESULT IN A MODERATE RISK
OF RIP CURRENTS TODAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...HEAVENER
NEAR TERM...HAYES
SHORT TERM...HAYES
LONG TERM...HEAVENER
AVIATION...HAYES/HEAVENER
MARINE...HAYES/HEAVENER
RIP CURRENTS...HAYES
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1238 AM EDT WED AUG 29 2012
.SYNOPSIS...
GREAT LAKES HIGH PRESSURE WILL CREST OVER OUR AREA ON THURSDAY
AND THEN SLIP DOWN TO THE CAROLINAS FRIDAY SENDING US A DAY OR TWO
OF HEAT. A COLD FRONTAL PASSAGE FROM THE NORTHWEST IS ANTICIPATED
SATURDAY. THE SHOWERY REMNANTS OF ISAAC MAY RIDE ALONG THAT FRONT
THROUGH OUR AREA LATE THIS LABOR DAY WEEKEND WITH ANOTHER COLD
FRONTAL PASSAGE POSSIBLE HERE LATE TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
A SECONDARY COLD FRONT WAS DROPPING THROUGH OUR REGION FROM NORTH
TO SOUTH THIS EVENING. IT HAD A WIND SHIFT ASSOCIATED WITH IT FROM
WEST NORTHWEST TO THE NORTH NORTHWEST.
THERE WERE FEW CLOUDS WITH THE FRONT. AS HIGH PRESSURE BEGINS TO
BUILD INTO OUR REGION TONIGHT, WE ARE ANTICIPATING A MOSTLY CLEAR
SKY. TEMPERATURES SHOULD DROP INTO THE 50S UP NORTH AND INTO THE
60S IN OUR CENTRAL AND SOUTHERN COUNTIES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
HIGH PRESSURE WILL BUILD ACROSS THE REGION ON WEDNESDAY AS THE
DRYING TREND CONTINUES. CONDITIONS OUTSIDE WILL CERTAINLY FEEL
LESS HUMID AND PRETTY COMFORTABLE WITH HIGHS GENERALLY INTO THE
LOWER 80S. 850MB TEMPERATURES ARE AROUND 10-12C, WHICH SUPPORT
SURFACE TEMPERATURES IN THE UPPER 70S TO LOWER 80S.
A SHORTWAVE ROTATES THROUGH THE MID LEVEL FLOW DURING THE
AFTERNOON/EVENING BUT ALL THAT IT LOOKS TO BRING TO OUR AREA IS
CLOUDS AS THE ATMOSPHERE LOOKS TO BE TOO DRY FOR MUCH ELSE TO
OCCUR.
&&
.LONG TERM /WEDNESDAY NIGHT INTO TUESDAY/...
500MB: A STRONG TROUGH IN COASTAL EASTERN CANADA WILL BE RELAXING
ITS INFLUENCE ON OUR AREA PERMITTING STRONG HOT RIDGING IN THE
CAROLINAS BY FRIDAY. THAT RIDGE REFORMS ALONG THE GULF COAST THIS
WEEKEND AS IT TRADES PLACES WITH THE DEPARTED ISAAC. MEANWHILE...
MODEL CONSENSUS TRACKS THE REMNANTS OF ISAAC EASTWARD INTO THE MID
ATLANTIC STATES EARLY NEXT WEEK....EITHER AS WARM FRONTAL WAVE ON
SATURDAYS COOL FRONT...OR ON A NEW N-S COLD FRONT FORMING IN THE
GREAT LAKES.
TEMPS: NEAR NORMAL THURSDAY THEN 5 TO 10 DEGREES ABOVE NORMAL
FRIDAY AND SATURDAY AND PROBABLY STILL ABOVE NORMAL SUNDAY THROUGH
TUESDAY BUT WITH LESS CERTAINTY ON DAY TO DAY DETAILS.
HAZARDS...NONE EVIDENT THROUGH SATURDAY. THEREAFTER...POSSIBLE
LOCALIZED FLOODING MONDAY INTO TUESDAY. THIS IS CONDITIONAL AND
STILL UNCERTAIN...TO ISAACS REMNANT MOISTURE/850 VORTICITY
FIELD/SURFACE MOISTURE CONVERGENCE TRACKING THROUGH THE MID
ATLANTIC STATES. NO HYDRO SECTION AS WE`RE TALKING DAYS 5-7 AND
THE MAXIMUM QPF MAY TRACK NORTH OF OUR AREA.
HEAT: HEAT INDEX IN THE MID 90S BOTH FRI AND SAT...BELOW CRITERIA
FOR HEAT ADVY BUT NOTABLE. MAX TEMPS NEAR 430 PM ON FRIDAY...LATE
DAY. FORTUNATELY RELATIVELY DRY HEAT.
WED NIGHT-THU NIGHT...COMFORTABLY COOL. PWATS BELOW NORMAL SO
NIGHTTIMES SHOULD BE COOLER THAN NORMAL. BLENDED 12Z/28 NCEP MOS
GUIDANCE WITH DRY HIGH PRESSURE AND SPECTACULAR LATE SUMMER
WEATHER FOR OUR AREA. LIGHT WIND. PATCHY FOG FOR AN HOUR OR 2 LATE
AT NIGHT IN THE USUAL COUNTRYSIDE LOCATIONS.
FRIDAY-SATURDAY...HEATS UP FOR A PROBABLE 2 DAY RUN OF 90-95F.
DEWPOINTS HIGHER ALONG THE COAST...UPPER 60S BUT INLAND...THESE
LOWER IN THE AFTN TO UPPER 50S AND LOWER 60S DELAWARE VALLEY
WESTWARD. WSW G AROUND 20 KTS FRI AND THEN A WEST WIND POSSIBLY
SHIFTING NW G UNDER 20 KTS SATURDAY. JUST RCD 12Z ECMWF KI/SWI
FIELDS SUGGEST THAT A SLIVER MOIST UNSTABLE AIR PRECEDES A WEAK
COOL FRONT THROUGH OUR AREA LATE FRI NIGHT. FOR NOW NO POPS SINCE
OCCURRENCE IS PROBABLY LATE AT NIGHT.
SUNDAY-TUESDAY...THE APPROACH OF ISAAC AND ITS UNCERTAINTIES ARE
CRITICAL TO THE FCST TEMPS/POPS THIS 3 DAY PERIOD. YDY THE ECMWF
WAS SOUTH BUT NO LONGER AND THIS IS A MUCH FIT FOR THE MORE
CONSISTENT GEFS. SO WHILE I CONSIDER THIS STILL A LOW CONFIDENCE
FCST ON THE DETAILS....I HAD ENOUGH CONFIDENCE TO RAISE HPC POPS
BY 15 TO 20 PCT ON MONDAY/MONDAY NIGHT IN THE INSTABILITY BURST
AHEAD OF 850 VORT MAX THAT IS ISAACS REMNANTS.
GEFS HINTS THAT THIS COULD BE A PRODUCTIVE EVENT FOR US...ITS
00Z/28 ENSEMBLES WITH A 10 PCT CHC OF A 48 HR 4 INCH TOTAL IN THE
NORTHERN PART OF OUR FCST AREA BY 00Z TUESDAY /LABOR DAY EVENING/.
GEFS PWATS ARE MODELED TO BE PLUS 2SD AS IS THE WAA 850MB SLY FLOW
COMPONENT. EARLY BUT INTERESTING....ESPECIALLY WITH A POSSIBLE
QSTRY FRONT WITH WHICH TO INTERACT. IT SHOULD BE STATED THAT THE
12Z GEFS DOES NOT HAVE 48 HR 10 PCT PROB OF 4 INCHES FOR OUR AREA.
SINCE WE`RE TALKING DAY 5-6-7...PLENTY OF TIME FOR MODEL
ADJUSTMENTS.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS CONTINUE EARLY THIS MORNING...WITH JUST SOME MID
LEVEL CLOUDINESS ACROSS PORTIONS OF SOUTHEAST PENNSYLVANIA. AS A
COLD FRONT DRIFTS SOUTH OF THE AREA...SURFACE WINDS WILL SHIFT TO
THE NORTH...AND INCREASE TO NEAR 10 KNOTS BY DAYBREAK AT KPHL AND
KACY. THE LIGHT GRADIENT SHOULD PREVENT ANY PATCHY MVFR FOG FROM
DEVELOPING.
DURING THE DAY...VFR CONDITIONS ARE EXPECTED. THE NORTHERLY FLOW
WILL PRODUCE WINDS NEAR 10 KNOTS THIS MORNING...AND GUSTS ARE
POSSIBLE AT KACY THROUGH ABOUT 1500 UTC. DURING THE AFTERNOON...
WINDS WILL BACK TO THE NORTHWEST AND PROBABLY DROP BELOW 10 KNOTS.
VFR CONDITIONS ARE EXPECTED TONIGHT. THERE MAY BE ENOUGH OF A LIGHT
NORTHWEST FLOW TO PRECLUDE MUCH IN THE WAY OF MVFR/IFR FOG TONIGHT.
THIS WILL BE ADDRESSED MORE FOR THE 1200 UTC FORECAST ISSUANCE.
OUTLOOK...
THURSDAY...POSSIBLE ISOLATED PATCHY MVFR FOG POSSIBLE THROUGH 13Z AT
THE USUAL LOCATIONS...OTHERWISE VFR. WIND BECOMING LIGHT W...G
UNDER 15 KTS.
FRIDAY...VFR. POSSIBLE MVFR FOG EARLY IN THE DAY. WSW G20 KTS
DURING THE DAY. LOW PROB ISOLATED SHOWER LATE AT NIGHT.
SATURDAY...VFR CONDITIONS ARE EXPECTED. THERE COULD BE WIDELY
SCATTERED SHOWER OR THUNDERSTORM...BUT CONFIDENCE IS BELOW
AVERAGE. W WIND TO START MAY SHIFT TO NW AND G UNDER 20 KTS.
SUNDAY...CONFIDENCE IS BELOW AVERAGE AND SO THE FCST IS VFR OCNL
CIGS BUT A POSSIBILITY OF MVFR CONDS IN SHOWERS AT NIGHT AND ESE
FLOW G UNDER 20 KTS.
&&
.MARINE...
SUB-ADVISORY CONDITIONS ARE EXPECTED TO CONTINUE ON THE AREA
WATERS.
A REINFORCING COLD FRONT WILL CROSS THE WATERS IN THE NEXT 2
HOURS. BEHIND THE FRONT...THE LOW LEVEL PUSH OF COOL AIR OVER THE
RELATIVELY WARM WATER SHOULD RESULT IN EFFICIENT MOMENTUM
TRANSFER. THE LATEST HRRR AND RAP OUTPUT SHOWS THE POTENTIAL FOR
25 KNOT GUSTS ACROSS THE SOUTHERN OCEAN WATERS AND LOWER DELAWARE
BAY BETWEEN 0900 AND 1100 UTC. NO HEADLINES YET AS THERE IS NOT
ENOUGH CONFIDENCE IN OCCURRENCE...BUT TRENDS WILL BE WATCHED FOR
GUSTS AS WE APPROACH 1000 UTC.
HIGH PRESSURE WILL BUILD IN FROM THE WEST ON WEDNESDAY WITH THE
GRADIENT GRADUALLY RELAXING THROUGH THE DAY. SEAS WILL REMAIN
FROM 3 TO 4 FEET ON THE OCEAN THROUGH WEDNESDAY.
OUTLOOK...
WEDNESDAY NIGHT THROUGH SUNDAY. NO HEADLINES ANTICIPATED.
FRIDAY AFTERNOON...THERE IS A SMALL CHANCE WE`LL NEED A WLY FLOW
SCA HEADLINE WITH GUSTY NEAR SHORE WINDS TO NEAR 25 KNOTS BUT FOR
NOW NOT PLAYING THIS UP.
SUNDAY...DEPENDING ON THE HIGH POSITION WITH RESPECT TO THE
MODELED ONCOMING ISAAC REMNANTS...WE MAY DEVELOP AN ESE SCA FLOW.
&&
.RIP CURRENTS...
IT APPEARS AS THOUGH THERE WILL BE A MODERATE RISK OF RIP
CURRENTS AGAIN FOR WEDNESDAY. WE ARE EXPECTING 2 TO 4 FOOT WAVES
WITH A 10 SECOND PERIOD. A NORTHERLY WIND AT 10 TO 15 MPH MAY
CONTRIBUTE TO ENHANCING THE RIP CURRENT RISK.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DRAG
NEAR TERM...IOVINO
SHORT TERM...MEOLA
LONG TERM...DRAG
AVIATION...DRAG/HAYES
MARINE...DRAG/HAYES/MEOLA
RIP CURRENTS...IOVINO
AREA FORECAST DISCUSSION
NWS DES MOINES IA
410 AM CDT WED AUG 29 2012
.SHORT TERM /TODAY/...
PRIMARY CONCERN TODAY WILL BE TEMPS. RAP DOES DEPICT SHORT WAVE
AND DECENT PV ANOMALY DROPPING INTO IA JUST WEST OF THE MO RIVER
WITH WEAK/MODERATE THERMODYNAMIC AND KINEMATIC FORCING. AIRMASS IS
QUITE DRY AS NOTED BY DARKENED WATER VAPOR IMAGERY...BUT EVEN
THOUGH MOISTURE IS LIMITED AN ISOLATED HIGH BASED SHOWER HAS
RECENTLY DEVELOPED JUST NW OF AMES. THUS WILL MENTION ISOLATED
LIGHT SHOWERS EAST EARLY...BUT EXPECT ANYTHING THAT IS OUT THERE
TO DISSIPATE AFTER SUNRISE.
MAIN QUESTION WILL BE HOW WARM TO GO TODAY. 08Z SURFACE ANALYSIS
SHOWS WARM FRONT ACROSS SRN MN PLACING IA FULLY IN THE WARM SECTOR.
MODELS GENERALLY DEPICT EASTWARD LOBE OF THERMAL RIDGE JUST BEHIND
THE FRONT WHICH WILL LIKELY PLACE WARMEST READINGS OVER NRN IA.
NAM RAW MODEL OUTPUT AND ASSOCIATED MOS HAS BEEN IN THE BALLPARK
WITH WARM UPS RECENTLY SO WILL GENERALLY FOLLOW GOING DRY
ADIABATIC...NOT SUPER ADIABATIC AS DEPICTED BY SOUNDINGS...WHICH
IS ALSO NEAR MOS OUTPUT DISCOUNTING VERY BULLISH MASON CITY
NUMBERS. THIS RESULTS IN WIDESPREAD MID 90S FOR HIGHS WITH WARMEST
ZONE BRUSHING UPPER 90S NRN TWO TIERS OF COUNTIES. NOT INCLUDED IN
THE FORECAST...BUT WOULD NOT BE SURPRISED TO SEE A FEW SITES
PUSHING 100F. INCREASING AND SOMEWHAT GUSTY SLY WINDS WILL
CERTAINLY HELP AND BOOST MIXING.
.LONG TERM /TONIGHT THROUGH TUESDAY/...MAIN FORECAST CONCERN
REMAINS FOCUSED ON TEMPS AND FIRE WEATHER CONCERNS THURSDAY...THEN
ON POPS WRT TO ISAAC REMNANTS OVER THE WEEKEND. MODELS ARE IN GOOD
AGREEMENT WITH THE OVERALL SYNOPTIC TRENDS THROUGH THE END OF THE
WORK WEEK...WITH THE NAM/SREF SLIGHTLY SLOWER/WEST THAN THE
GFS/ECMWF WRT ISAAC TRACK.
TONIGHT INTO THURSDAY...WAA CONTINUES THROUGH TOMORROW AHEAD OF A
WEAK FRONTAL BOUNDARY THAT LOOKS TO SAG SOUTHWARD INTO NORTHERN
IOWA LATE THURSDAY NIGHT INTO FRIDAY MORNING. TWEAKED MAX TEMPS
UP FOR THURSDAY AS MODELS CONTINUE WITH STRONG MIXING FROM AROUND
850MB THROUGH THE AFTERNOON. 850MB TEMPS RANGE FROM +23C TO 26C BY
00Z FRIDAY. PRESSURE GRADIENT STRENGTHENS AS WELL WITH THE FRONT
SAGGING FURTHER SOUTH WHICH WILL AID IN SOME HIGHER SUSTAINED
WINDS. TWEAKED UP WINDS SLIGHTLY BUT REMAIN UNDER RED FLAG WARNING
CRITERIA. SEE FIRE WEATHER DISCUSSION FOR FURTHER DETAILS.
FRIDAY THROUGH SUNDAY...THE FORECAST AREA SHOULD BEGIN TO SEE SOME
HIGHER CLOUDS STREAMING INTO SOUTHERN IOWA WRT TO ISAAC MOVING
NORTHWARD INTO EASTERN OK/SW MO AREA. GFS PUSHES THE LOW SLIGHTLY
FURTHER NORTH BUT ALL MODELS LOOKING AT SOME RAIN POTENTIAL IN THE
SOUTHEAST FRIDAY NIGHT THROUGH SATURDAY NIGHT. LOWERED MAX TEMPS
ON FRIDAY AND SATURDAY TO REFLECT THE SLIGHTLY FURTHER PUSH OF
ISAAC AND MORE CLOUD COVER. ISAAC FINALLY PUSHES EAST BY SUNDAY
BEFORE A WEAK SHORTWAVE MAKES IT WAY ACROSS MN SUNDAY NIGHT INTO
MONDAY. HAVE SOME SMALL POPS GOING ACROSS THE NORTH DURING THE
AFOREMENTIONED TIME FRAME.
MONDAY AND TUESDAY...LOW CONFIDENCE WITH ANY POPS DURING THIS TIME
FRAME WITH THE EXTENDED MODELS SHOWING SIGNIFICANT DISCREPANCIES
WRT UPPER LEVEL PATTERN. ECMWF IS A LITTLE MORE NORTHWESTERLY FLOW
THAN THE ZONAL FLOW DEPICTED BY THE GFS...AND EACH MODEL HAS A FEW
SHORTWAVES AFFECTING THE STATE BUT AT DIFFERENT TIMES.
&&
.AVIATION...29/06Z
LOW PRESSURE WILL STRENGTHEN TO THE WEST WITH A S-SWLY FLOW OVER THE
TAF SITES. FEEL THERE WILL BE ENOUGH WIND TO KEEP FOR FROM FORMING
TONIGHT. WINDS WILL GUST TO AROUND 20 KTS OR SO OVER THE NWRN HALF
OF THE STATE WEDNESDAY AFTERNOON. WINDS WILL DROP OFF AFTER SUNSET.
&&
.FIRE WEATHER...VERY HOT...DRY AND WINDY CONDITIONS ARE FORECAST
TODAY AND AGAIN TOMORROW. THURSDAY WILL BE THE MOST SIGNIFICANT
FIRE WEATHER POTENTIAL AS SUSTAINED WINDS WILL BE MUCH STRONGER
THAN TODAY. SUSTAINED WINDS TODAY ARE FORECAST TO RANGE AROUND 10
TO 15 MPH IN MOST SPOTS WITH SOME GUSTS TO NEAR 30 MPH BY THIS
AFTERNOON. BY THURSDAY...MIXING SHOULD INCREASE AND CAUSE
SUSTAINED WINDS TO RANGE FROM 20 TO 25 MPH WITH GUSTS LIKELY TO
TOP NEAR 35 MPH OR A BIT HIGHER BY THE AFTERNOON. THE STRONGEST
WINDS WILL BE NORTH OF HIGHWAY 30. THE RELATIVE HUMIDITY IS
EXPECTED TO FALL TO NEAR 20 TO 25 PERCENT BY THIS AFTERNOON AND
AGAIN THURSDAY AFTERNOON. HELD OFF ON ISSUING A RED FLAG WARNING
AS SUSTAINED WINDS REMAIN UNDER 25 MPH FOR A MORE WIDESPREAD AREA
ON THURSDAY.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...FIRE WEATHER WATCH FOR THURSDAY
AFTERNOON AND EVENING FOR EMMET...KOSSUTH...WINNEBAGO...WORTH...
PALO ALTO...HANCOCK AND CERRO GORDO COUNTIES.
&&
$$
SHORT TERM...SMALL
LONG TERM...PODRAZIK
AVIATION...MS AUG 12
FIRE WEATHER...PODRAZIK
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1137 PM CDT TUE AUG 28 2012
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
VFR CONDITIONS ARE EXPECTED THROUGH 30/06Z. LOW LEVEL JET APPEARS
IT WILL BE STRONG ENOUGH TONIGHT AND SURFACE WINDS LIGHT ENOUGH TO
INCLUDE LOW LEVEL WIND SHEAR AT TAF SITES UNTIL SURFACE WINDS
INCREASE BY MID WEDNESDAY MORNING.
CHERMOK
&&
.PREV DISCUSSION... /ISSUED 308 PM CDT TUE AUG 28 2012/
DISCUSSION...
FORECAST CONCERNS CENTER AROUND HOT TEMPS...FIRE WEATHER
CONDITIONS...AND REMNANTS OF ISAAC.
LATEST WATER VAPOR IMAGERY AND 500MB RAP ANALYSIS SHOWS LARGE DOME
OF HIGH PRESSURE OVER THE CENTRAL CONUS WITH A WEAK IMPULSE ON TOP
RIDING OVER THE RIDGE OVER SOUTHEASTERN WYOMING. UPSTREAM...A
SHORTWAVE TROF CONTINUES TO MOVE ONTO THE WEST COAST. AT THE
SFC...WARM SOUTHWESTERLY FLOW EXTENDS OVER ALL OF THE FORECAST
AHEAD OF SFC LOW PRESSURE CENTERED OVER CENTRAL SOUTH DAKOTA.
ACCAS FIELD REMAINS OVER OUR NORTHERN COUNTIES WHERE MID LEVEL
MOISTURE IS PROGGED TO REMAIN OVERNIGHT AND INTO WEDNESDAY. SOME
VERTICAL MOTION IS PROGGED OVER THIS SAME AREA OVERNIGHT AS ERN
WYOMING WAVE RIDES THE RIDGE TOWARD THE AREA. WITH EXTREMELY DRY
LEVELS BELOW 650MB...DO NOT EXPECT ANY PCPN TO REACH THE GROUND IF
ANY CAN/DOES DEVELOP.
FOCUS THEN TURNS TO FIRE WEATHER CONDITIONS ACROSS OUR NORTHERN
COUNTIES WEDNESDAY AFTERNOON. RED FLAG WARNING CRITERIA WILL BE
VERY CLOSE...ESPECIALLY IF WE CAN MIX OUT OUR SFC DEWPOINTS. WITH
MODEST SOUTHWESTERLY LOW LEVEL FLOW...WE SHOULD MIX OUT TEMPS QUITE
WELL DURING THE AFTERNOON PUSHING HIGHS INTO THE LOWER 100S IN
OUR NORTH TO THE UPPER 90S ELSEWHERE. DO EXPECT SIMILAR READINGS
ON THURSDAY AS 850MB TEMPS AROUND THE SAME IN THE UPPER 20S WITH
STRONG SOUTHWESTERLY MIXING. AS A RESULT...WILL GO WITH A RED FLAG
WARNING IN THE NORTHWEST COUNTIES AND MAY NEED TO CONSIDER A
HEADLINE OF SORTS FOR THURSDAY AS WELL.
MODEL CONSENSUS BRINGS ISAAC REMNANTS AS FAR NORTH AS OUR
SOUTHEASTERN TIER OF COUNTIES FRIDAY NIGHT INTO SATURDAY. AS A
RESULT...HAVE ADDED LOW POPS...INCREASED SKY COVER AND LOWERED
HIGHS SLIGHTLY. THIS SYSTEM WILL QUICKLY DRIFT EAST OF THE AREA
AND SOUTHWESTERLY UPPER LEVEL FLOW WILL FOLLOW WITH A FEW EMBEDDED
SHORTWAVES PROGGED TO TRAVEL ACROSS THE REGION. AS A RESULT...HAVE
CONTINUED SOME SMALL CHANCE POPS DAYS 6 & 7 BUT CONFIDENCE IS
FAIRLY LOW.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...RED FLAG WARNING FROM 1 PM TO 9 PM CDT WEDNESDAY FOR NEZ011-012-
015>018-030>033-042.
IA...NONE.
&&
$$