Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/19/12
AREA FORECAST DISCUSSION...CORRECTED
NWS TAMPA BAY RUSKIN FL
900 PM EDT FRI MAY 18 2012
.UPDATE (TONIGHT)...
01Z WATER VAPOR AND H4 RUC ANALYSIS SHOWS THE SOUTHEASTERN STATES
REMAIN UNDER CONTROL OF UPPER LEVEL TROUGHING ANCHORED BY A CLOSED
LOW FEATURE SPINNING NEAR THE CAROLINA COAST. WV IMAGERY SHOWS THAT
THE DEEP LAYER WESTERLY FLOW ON THE SOUTHERN SIDE OF THIS
CIRCULATION IS SUPPLYING THE REGION WITH A CONTINUOUS INFLUX OF DRY
MID/UPPER LEVEL AIR FROM OVER THE GULF OF MEXICO. THIS AIRMASS ABOVE
OUR HEADS IS SAMPLED WELL IN THE 19/00Z KTBW SOUNDING PROFILE WHICH
SHOWS DEWPOINT DEPRESSIONS EXCEEDING 40C ABOVE 650MB. THETA-E VALUES
IN THE 700 TO 500MB LAYER ARE ALSO BETWEEN 316-320K THIS EVENING.
THESE FACTORS ARE QUITE HOSTILE TO DEEP CONVECTION...AND IF IT WAS
NOT FOR THE UPPER LEVEL FORCING ASSOCIATED WITH THE LATE SEASON
TROUGH...IT IS DOUBTFUL THAT WE WOULD EVEN BE ABLE TO SUSTAIN THE
FEW STORMS WHICH HAVE FOUGHT THROUGH THE DRY AIR OVER OUR INTERIOR
COUNTIES THE PAST SEVERAL HOURS. SO...IT IS TOUGH TO REALLY CLASSIFY
THIS ACTIVITY AS TRUE "SEA-BREEZE CONVECTION"...ALTHOUGH THE LOW
LEVEL FOCUS OF THE SEA-BREEZE AIDED THE INITIAL ASCENT. HAVE
INCREASED THE POPS TO AROUND 30% OVER THE INTERIOR FOR THE NEXT
COUPLE OF HOURS TO REPRESENT THE ONGOING ACTIVITY...AND THE
LIKELIHOOD THAT IT WILL PERSIST THROUGH 03-04Z DUE TO THE SYNOPTIC
FORCING. AFTER THIS TIME...EXPECT ANY LINGERING CONVECTION TO FADE
AND LEAVE US WITH A QUIET AND SEASONABLE OVERNIGHT PERIOD. RAIN
CHANCES WILL FALL TO 10% OR LESS OVER THE ENTIRE FORECAST AREA AFTER
MIDNIGHT THROUGH THE MORNING HOURS OF SATURDAY.
&&
.PREVIOUS DISCUSSION (SATURDAY THROUGH SUNDAY)...
IN THE SHORT TERM THE MAIN WEATHER FEATURE ACROSS THE AREA WILL
REMAIN THE TROUGH ACROSS THE SOUTHEASTERN STATES. AT 500 MB A LOW
WILL BE CUTTING OFF TONIGHT AND INTO THE WEEKEND OFF THE NORTH
CAROLINA COAST. THE LOW WILL MAINTAIN A NEARLY STATIONARY POSITION
AND SPIN IN PLACE THROUGH THE REMAINDER OF THE WEEKEND. THE SURFACE
PATTERN WILL REFLECT THIS UPPER LEVEL FEATURE WITH A LOW DEVELOPING
IN NEARLY THE SAME PLACE...AND A WEAK SURFACE TROUGH OR FRONTAL
BOUNDARY LINGERING ACROSS THE EXTREME NORTHERN PENINSULA. SURFACE
OBS THIS AFTERNOON SHOW A DISTINCT NORTH TO NORTHEAST FLOW NORTH OF
THE FORECAST AREA WITH LOWER DEWPOINTS AND COOLER TEMPERATURES. A
LITTLE OF THE DRIER AIRMASS WILL INCH INTO THE FAR NORTHERN ZONES ON
SATURDAY WITH DEWPOINTS FALLING INTO THE UPPER 50S. THIS WILL BRING
SOME COOLER NIGHTTIME LOWS INTO THE NORTHERN INTERIOR AREAS BY
SATURDAY NIGHT AND SUNDAY BUT ELSEWHERE THERE SHOULD BE LITTLE TO NO
AIRMASS CHANGE. DAYTIME TEMPERATURES SHOULD SHOW ONLY MINOR IMPACTS
AS THE DRIER AIR MAY BRING LESS CLOUDS...MORE SUN AND BETTER
HEATING. RAIN CHANCES WILL CONTINUE TO BE HIGHEST ACROSS THE
INTERIOR AREAS GIVEN THE INLAND PROGRESSION OF THE WEST COAST SEA
BREEZE. SHADED POPS A LITTLE LOWER ACROSS THE NORTH FOR THE DRY
AIRMASS AND NOTICED AN OVERALL DRYING TREND IN MODEL POPS.
&&
.AVIATION...
VFR THROUGH MID DAY SATURDAY...THEN SHOWERS AND THUNDERSTORMS
POSSIBLE DURING THE AFTERNOON HOURS.
&&
.MARINE...
HIGH PRESSURE BUILDING IN FROM THE NORTH WILL SLOWLY TIGHTEN THE
LOCAL GRADIENT OVERNIGHT INTO SATURDAY. IN RESPONSE...EXPECT WINDS
TO SHIFT TO A MORE EASTERLY DIRECTION WITH A MODEST INCREASE IN
SPEED LATER TONIGHT THROUGH THE UPCOMING WEEKEND. AT THIS
TIME...WINDS ANDS SEAS ARE EXPECTED TO GENERALLY REMAIN BELOW
HEADLINE CRITERIA.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 71 89 70 90 / 10 20 10 30
FMY 72 91 68 92 / 10 20 20 30
GIF 68 90 68 91 / 20 40 20 30
SRQ 69 87 69 88 / 10 20 10 30
BKV 63 90 64 91 / 10 20 20 30
SPG 73 88 71 89 / 10 20 10 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...MROCZKA
PREVIOUS DISCUSSION...JOHNSON
AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS MIAMI FL
159 PM EDT THU MAY 17 2012
.AVIATION...VFR PREVAILS. THERE HAVE BEEN PERIODS OF MVFR CIGS.
HOWEVER, THEY`VE BROKEN UP IN THE PAST HOUR. BIG CHALLENGE IS WITH
REGARDS TO CONVECTION. LIKE YESTERDAY, THE AREA IS SHROUDED IN
CLOUD COVER AND TEMPERATURES ARE ONLY IN THE LOWER 80S. HOWEVER,
THERE IS A SOUTHEAST WIND ALONG THE ATLANTIC COAST SO WE COULD
STILL GET CONVERGENCE AND THE DEVELOPMENT OF SHRA/TSRA IN THE NEXT
FEW HOURS...SO MAINTAINED TEMPO FOR TSRA. ANY STORMS COULD PRODUCE
BRIEF IFR CONDITIONS ALONG WITH STRONG WIND GUSTS, SHOULD THEY
DEVELOP. ANY ACTIVITY WHICH DEVELOPS IS EXPECTED TO GRADUALLY WANE
THIS EVENING...BUT MAINTAINED VCSH OVERNIGHT. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 908 AM EDT THU MAY 17 2012/
UPDATE...
SOME CHANGES WERE MADE TO THE SHORT TERM FORECAST. THE SHORT TERM
WIND FORECAST IS PROBLEMATIC IN THAT THE CONVECTION THAT PASSED
THROUGH THE REGION EARLIER THIS MORNING DISRUPTED THE SYNOPTIC
FLOW AND THE WINDS ARE CURRENTLY SOMEWHAT VARIABLE. BUT THE
CONSENSUS OF THE LATEST GUIDANCE SUGGESTS THAT A SOUTH TO
SOUTHWESTERLY FLOW IS LIKELY TO BECOME RE-ESTABLISHED ACROSS THE
REGION LATER THIS MORNING OR THIS AFTERNOON. ALSO UPDATED THE
MARINE FORECAST TO REFLECT THE SHOWER AND THUNDERSTORM ACTIVITY
ACROSS THE ATLANTIC WATERS FROM EARLIER THIS MORNING BUT THE
THUNDERSTORM ACTIVITY IS CURRENTLY SUBSIDING. FOR THE FORECAST FOR
THE REMAINDER OF THE DAY...WILL LEAVE CURRENT FORECAST FOR
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. ALTHOUGH ACTIVITY
HAS SUBSIDED THIS MORNING...SEVERAL SYNOPTIC FACTORS SUGGEST THAT
CONVECTION COULD START LATER THIS MORNING OR INTO THE AFTERNOON.
THE FACTORS INCLUDE AN UPPER LEVEL JET PASSING THROUGH THE
REGION AND LOW LEVEL MASS AND MOISTURE CONVERGENCE CONTINUING
ACROSS THE REGION. PLUS RECENT SATELLITE IMAGERY INDICATES SOME
AREAS OF CLEARING ACROSS THE PENINSULA WHICH MAY ALLOW SUFFICIENT
DAY TIME HEATING TO INITIATE CONVECTION. BUT BEST CHANCES OF
CONVECTION IS PROBABLY STILL THE EASTERN HALF OF THE PENINSULA AND
THE ADJACENT ATLANTIC WATERS.
60
PREV DISCUSSION... /ISSUED 741 AM EDT THU MAY 17 2012/
AVIATION...VFR WILL PREVAIL WITH EXTENSIVE MID/HIGH LEVEL
CLOUDINESS BEHIND DEPARTING CONVECTION NOW OVER THE ATLANTIC.
IT WILL TAKE TIME FOR THE AIRMASS TO RECOVER, AND HRRR ACTUALLY
DOES NOT SHOW CONVECTION ON THE EAST COAST UNTIL NEAR KPBI BY 4
PM. IT DOES DEVELOP A BROKEN LINE OF CONVECTION LATE THIS
AFTERNOON FROM JUST NORTH OF LAKE OKEECHOBEE TO ACROSS LEE COUNTY
BEFORE MOVING SLOWLY SE INTO THE AREA. THIS LATE START TO
CONVECTION LOOKS REASONABLE, SO HAVE TEMPO TSRA/MVFR FROM 19-23Z
FOR ALL EAST COAST TERMINALS AND VCTS FOR KAPF. MAY NEED TO ADD
TEMPO THERE SHOULD A BROKEN LINE OF CONVECTION DEVELOP SO WILL
MONITOR TRENDS. ANY STORM LATE THIS AFTERNOON/EVENING WILL BE
CAPABLE OF PRODUCING BRIEF IFR CONDITIONS ALONG WITH STRONG WIND
GUSTS. /GREGORIA
PREV DISCUSSION... /ISSUED 330 AM EDT THU MAY 17 2012/
DISCUSSION...S FLA HAS BEEN UNDER THE INFLUENCE OF THE UPPER TROUGH
OVER THE E U.S. COAST THAT CURRENTLY EXTENDS SW ACROSS THE SE U.S.
INTO THE GULF OF MEX. TODAY AND INTO THE WEEKEND...A CLOSED LOW WILL
DEVELOP OVER THE SE U.S./ADJACENT ATLC AND WILL PERSIST THROUGH THE
WEEKEND INTO EARLY NEXT WEEK DUE TO THE DEVELOPMENT OF A REX BLOCK
AS A STRONG UPPER RIDGE EXTENDS NW OVER NEW ENGLAND FROM THE ALTC
HIGH. THIS STOPS THE MOVEMENT OF THE UPPER LOW. BY MIDWEEK NEXT
WEEK...LONG RANGE MODELS DIFFER SOME ON THE SCENARIO...BUT A DEEP
UPPER TROUGH OVER THE WESTERN U.S. MOVES E WHICH PULLS THE CLOSED
LOW N AND ABSORBING THE FORMER SYSTEM. THE GFS INDICATES MULTIPLE
SMALL UPPER TROUGHS THAT MAY CROSS FLA WITH THE ECMWF INDICATING A
WESTERLY FLOW ALOFT WHICH MAY BRING MINIMAL SHORT WAVES ACROSS THE
AREA.
SHORT TERM...(TODAY-SATURDAY)...TODAY COULD BE MORE ACTIVE THAN
THURSDAY. A 500 MB 40 KT WIND AXIS MOVES NE ACROSS S CENTRAL FLA
WITH S FLA IN THE RFQ WITH SOME SPEED DIVERGENCE. WITH E/W COAST SEA
BREEZES DEVELOPING ALONG WITH THE AMPLE POSSIBILITY OF MORE
INSOLATION...VERY HIGH POPS WITH NUMEROUS TO WIDESPREAD
SHOWERS/THUNDERSTORMS POSSIBLE INTERIOR AND E. THERE WILL BE MAINLY
EVENING SHOWERS/THUNDERSTORMS E THIS EVENING BUT WITH THE MOIST
SW FLOW...ACTIVITY WILL STILL MOVE FROM THE GULF ACROSS THE
PENINSULA. POPS DIFFER BETWEEN MODELS FRIDAY BUT THE SURFACE
TROUGH...WHICH IS A REFLECTION OF THE UPPER TROUGH TO THE
NW...REMAINS NW OF S FLA AND S FLA REMAINS UNDER THE VERY MOIST
REGIME LIKE TODAY. THUS...WILL GO ABOVE MAV POPS. FRIDAY NIGHT A
SW FLOW ALOFT REMAINS BUT WITH THE SURFACE TROUGH DRAGGING
THROUGH...POPS LOWER. ON SATURDAY...SOME DRYING OCCURS.
EXTENDED PERIOD...(SUNDAY-WEDNESDAY)...AS MENTIONED ABOVE...THE
LONG RANGE PATTERN VARIES PER MODEL AND SOME DECREASE IN CONFIDENCE
OF THE POSSIBILITIES EXISTS. WITH THE SW UPPER FLOW PROJECTED TO
PERSIST...SOME RIPPLES MOVING THROUGH AND WITH VARIATION ON MODEL
PRECIPITATION FORECAST...WILL FOLLOW MEX GUIDANCE BUT EXPECT MORE
ACTIVITY IN THE INTERIOR AND NE THROUGH THE PERIOD AS THE LOW LEVEL
EASTERLY FLOW EXPECTED SHUNTING PRECIPITATION A BIT TO THE N.
MARINE...
WINDS GENERALLY LESS THAN 10 KNOTS WITH AND SEAS 3 FEET OR LESS. THE
MAIN PROBLEMS WILL BE THE SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS.
FIRE WEATHER...
AMPLE RAIN AND HIGH HUMIDITY EQUAL NO PROBLEMS TODAY AND THROUGH THE
WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 84 72 86 72 / 70 50 50 40
FORT LAUDERDALE 85 74 87 75 / 70 50 50 40
MIAMI 85 73 88 74 / 70 50 50 40
NAPLES 83 71 85 70 / 50 50 50 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
940 AM EDT THU MAY 17 2012
.DISCUSSION...
CURRENTLY...WEAK SURFACE TROUGH EXTENDS NNE FROM THE YUCATAN TO
APALACHEE BAY AND INTO SE GA WITH BROAD MID/UPPER TROUGH COVERING
THE NRN GOMEX. RUC INIT PANELS 80-90KT H25 JET CORE PUNCHING OVER
THE TOP OF THE STATE WITH BEST DIVG HAVING SHIFTED EAST..AND NOW
EXTENDS FROM SOUTH FL NEWD ACROSS THE BAHAMAS AND INTO THE ATLC.
VISIBLE SAT IMAGERY SHOWS EXTENSIVE MULTI-LAYERED CLOUDS COVERING
THE CWA FROM OSCEOLA/BREVARD SWD...WITH SOME OCNL BREAKS DEVELOPING
TO THE N/W. SOUNDER/RAOB DATA SHOW PWATS RANGING FROM 1.5" ACROSS
THE NORTH TO 1.8" OR SO NEAR LAKE OKEE...WITH H50 TEMPS -10C/-11C
AND EVEN COOLER (-14C @JAX) OVER NORTH FL.
TODAY...LIGHT S-SW FLOW EXPECTED AGAIN TODAY ON EAST SIDE OF WEAK
SURFACE TROUGH. AXIS OF THE MID LEVEL TROUGH WILL SLIDE EWD WITH
INCREASING MID LEVEL PVA COUNTERACTING THE EWD SHIFT OF JET FORCED
ASCENT AWAY FROM THE PENINSULA TO SOME DEGREE. EXPECT TODAY TO BE
MORE CONVECTIVELY ACTIVE OVERALL...WITH EARLIER ONSET COMPARED TO
WED. LACK OF WIDESPREAD OVC CLOUD DECK SHOULD ALLOW BETTER SURFACE
HEATING AND THUS GREATER INSTABILITY AND STRONGER MORE NUMEROUS
AFTERNOON STORMS...WHILE CONTINUATION OF SOME COMPONENT OF FORCED
ASCENT WOULD FAVOR ACTIVITY CONTINUING PAST SUNSET FOR AT LEAST A
FEW HOURS.
CURRENT FCST HAS A GOOD HANDLE ON SITUATION WITH SLIGHTLY HIGHER POP
DISTRIBUTION SOUTH.
&&
.AVIATION...MULTILAYERED BROKEN CLOUDS/SHRA SOUTH/EAST OF KTIX-KAGR
WITH SOME IFR STRATUS OVER NORTH FL....SWD TO ABOUT KLEE. ISOLATED
SHRA/TS STARTING AROUND 16Z. ACTIVITY INCREASING IN COVERAGE AND
BECOMING NMRS AFTER 18Z WITH LOCAL IFR CIGS/VSBYS IN STORMS. SOME
STORMS MAY PRODUCE WIND GUSTS OVER 35KT THIS AFTERNOON AND EVENING
THROUGH ABOUT 02Z-03Z.
&&
.MARINE...
TODAY-TONIGHT...PRIMARY MARINE CONCERN CONTINUES TO BE OFFSHORE
MOVING THUNDERSTORMS THIS AFTERNOON/EVENING. WINDS REMAIN 10KTS OR
LESS OUT OF THE S-SW WITH SEAS 1-2FT NEARSHORE AND 2-3FT OFFSHORE
IN A LONG PERIOD SWELL.
&&
.FIRE WEATHER...
NO RH/WIND CONCERNS TODAY. NUMEROUS AFTERNOON/EVENING SHRAS/TS.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...CRISTALDI
LONG TERM/IMPACT WX...WIMMER
AREA FORECAST DISCUSSION
NWS MIAMI FL
908 AM EDT THU MAY 17 2012
.UPDATE...
SOME CHANGES WERE MADE TO THE SHORT TERM FORECAST. THE SHORT TERM
WIND FORECAST IS PROBLEMATIC IN THAT THE CONVECTION THAT PASSED
THROUGH THE REGION EARLIER THIS MORNING DISRUPTED THE SYNOPTIC
FLOW AND THE WINDS ARE CURRENTLY SOMEWHAT VARIABLE. BUT THE
CONSENSUS OF THE LATEST GUIDANCE SUGGESTS THAT A SOUTH TO
SOUTHWESTERLY FLOW IS LIKELY TO BECOME RE-ESTABLISHED ACROSS THE
REGION LATER THIS MORNING OR THIS AFTERNOON. ALSO UPDATED THE
MARINE FORECAST TO REFLECT THE SHOWER AND THUNDERSTORM ACTIVITY
ACROSS THE ATLANTIC WATERS FROM EARLIER THIS MORNING BUT THE
THUNDERSTORM ACTIVITY IS CURRENTLY SUBSIDING. FOR THE FORECAST FOR
THE REMAINDER OF THE DAY...WILL LEAVE CURRENT FORECAST FOR
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. ALTHOUGH ACTIVITY
HAS SUBSIDED THIS MORNING...SEVERAL SYNOPTIC FACTORS SUGGEST THAT
CONVECTION COULD START LATER THIS MORNING OR INTO THE AFTERNOON.
THE FACTORS INCLUDE AN UPPER LEVEL JET PASSING THROUGH THE
REGION AND LOW LEVEL MASS AND MOISTURE CONVERGENCE CONTINUING
ACROSS THE REGION. PLUS RECENT SATELLITE IMAGERY INDICATES SOME
AREAS OF CLEARING ACROSS THE PENINSULA WHICH MAY ALLOW SUFFICIENT
DAY TIME HEATING TO INITIATE CONVECTION. BUT BEST CHANCES OF
CONVECTION IS PROBABLY STILL THE EASTERN HALF OF THE PENINSULA AND
THE ADJACENT ATLANTIC WATERS.
60
&&
.PREV DISCUSSION... /ISSUED 741 AM EDT THU MAY 17 2012/
AVIATION...VFR WILL PREVAIL WITH EXTENSIVE MID/HIGH LEVEL
CLOUDINESS BEHIND DEPARTING CONVECTION NOW OVER THE ATLANTIC.
IT WILL TAKE TIME FOR THE AIRMASS TO RECOVER, AND HRRR ACTUALLY
DOES NOT SHOW CONVECTION ON THE EAST COAST UNTIL NEAR KPBI BY 4
PM. IT DOES DEVELOP A BROKEN LINE OF CONVECTION LATE THIS
AFTERNOON FROM JUST NORTH OF LAKE OKEECHOBEE TO ACROSS LEE COUNTY
BEFORE MOVING SLOWLY SE INTO THE AREA. THIS LATE START TO
CONVECTION LOOKS REASONABLE, SO HAVE TEMPO TSRA/MVFR FROM 19-23Z
FOR ALL EAST COAST TERMINALS AND VCTS FOR KAPF. MAY NEED TO ADD
TEMPO THERE SHOULD A BROKEN LINE OF CONVECTION DEVELOP SO WILL
MONITOR TRENDS. ANY STORM LATE THIS AFTERNOON/EVENING WILL BE
CAPABLE OF PRODUCING BRIEF IFR CONDITIONS ALONG WITH STRONG WIND
GUSTS. /GREGORIA
PREV DISCUSSION... /ISSUED 330 AM EDT THU MAY 17 2012/
DISCUSSION...S FLA HAS BEEN UNDER THE INFLUENCE OF THE UPPER TROUGH
OVER THE E U.S. COAST THAT CURRENTLY EXTENDS SW ACROSS THE SE U.S.
INTO THE GULF OF MEX. TODAY AND INTO THE WEEKEND...A CLOSED LOW WILL
DEVELOP OVER THE SE U.S./ADJACENT ATLC AND WILL PERSIST THROUGH THE
WEEKEND INTO EARLY NEXT WEEK DUE TO THE DEVELOPMENT OF A REX BLOCK
AS A STRONG UPPER RIDGE EXTENDS NW OVER NEW ENGLAND FROM THE ALTC
HIGH. THIS STOPS THE MOVEMENT OF THE UPPER LOW. BY MIDWEEK NEXT
WEEK...LONG RANGE MODELS DIFFER SOME ON THE SCENARIO...BUT A DEEP
UPPER TROUGH OVER THE WESTERN U.S. MOVES E WHICH PULLS THE CLOSED
LOW N AND ABSORBING THE FORMER SYSTEM. THE GFS INDICATES MULTIPLE
SMALL UPPER TROUGHS THAT MAY CROSS FLA WITH THE ECMWF INDICATING A
WESTERLY FLOW ALOFT WHICH MAY BRING MINIMAL SHORT WAVES ACROSS THE
AREA.
SHORT TERM...(TODAY-SATURDAY)...TODAY COULD BE MORE ACTIVE THAN
THURSDAY. A 500 MB 40 KT WIND AXIS MOVES NE ACROSS S CENTRAL FLA
WITH S FLA IN THE RFQ WITH SOME SPEED DIVERGENCE. WITH E/W COAST SEA
BREEZES DEVELOPING ALONG WITH THE AMPLE POSSIBILITY OF MORE
INSOLATION...VERY HIGH POPS WITH NUMEROUS TO WIDESPREAD
SHOWERS/THUNDERSTORMS POSSIBLE INTERIOR AND E. THERE WILL BE MAINLY
EVENING SHOWERS/THUNDERSTORMS E THIS EVENING BUT WITH THE MOIST
SW FLOW...ACTIVITY WILL STILL MOVE FROM THE GULF ACROSS THE
PENINSULA. POPS DIFFER BETWEEN MODELS FRIDAY BUT THE SURFACE
TROUGH...WHICH IS A REFLECTION OF THE UPPER TROUGH TO THE
NW...REMAINS NW OF S FLA AND S FLA REMAINS UNDER THE VERY MOIST
REGIME LIKE TODAY. THUS...WILL GO ABOVE MAV POPS. FRIDAY NIGHT A
SW FLOW ALOFT REMAINS BUT WITH THE SURFACE TROUGH DRAGGING
THROUGH...POPS LOWER. ON SATURDAY...SOME DRYING OCCURS.
EXTENDED PERIOD...(SUNDAY-WEDNESDAY)...AS MENTIONED ABOVE...THE
LONG RANGE PATTERN VARIES PER MODEL AND SOME DECREASE IN CONFIDENCE
OF THE POSSIBILITIES EXISTS. WITH THE SW UPPER FLOW PROJECTED TO
PERSIST...SOME RIPPLES MOVING THROUGH AND WITH VARIATION ON MODEL
PRECIPITATION FORECAST...WILL FOLLOW MEX GUIDANCE BUT EXPECT MORE
ACTIVITY IN THE INTERIOR AND NE THROUGH THE PERIOD AS THE LOW LEVEL
EASTERLY FLOW EXPECTED SHUNTING PRECIPITATION A BIT TO THE N.
MARINE...
WINDS GENERALLY LESS THAN 10 KNOTS WITH AND SEAS 3 FEET OR LESS. THE
MAIN PROBLEMS WILL BE THE SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS.
FIRE WEATHER...
AMPLE RAIN AND HIGH HUMIDITY EQUAL NO PROBLEMS TODAY AND THROUGH THE
WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 84 72 86 72 / 70 50 50 40
FORT LAUDERDALE 85 74 87 75 / 70 50 50 40
MIAMI 85 73 88 74 / 70 50 50 40
NAPLES 83 71 85 70 / 50 50 50 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...60/BD
AVIATION/RADAR...57/DG
AREA FORECAST DISCUSSION
NWS MIAMI FL
741 AM EDT THU MAY 17 2012
.AVIATION...VFR WILL PREVAIL WITH EXTENSIVE MID/HIGH LEVEL
CLOUDINESS BEHIND DEPARTING CONVECTION NOW OVER THE ATLANTIC.
IT WILL TAKE TIME FOR THE AIRMASS TO RECOVER, AND HRRR ACTUALLY
DOES NOT SHOW CONVECTION ON THE EAST COAST UNTIL NEAR KPBI BY 4
PM. IT DOES DEVELOP A BROKEN LINE OF CONVECTION LATE THIS
AFTERNOON FROM JUST NORTH OF LAKE OKEECHOBEE TO ACROSS LEE COUNTY
BEFORE MOVING SLOWLY SE INTO THE AREA. THIS LATE START TO
CONVECTION LOOKS REASONABLE, SO HAVE TEMPO TSRA/MVFR FROM 19-23Z
FOR ALL EAST COAST TERMINALS AND VCTS FOR KAPF. MAY NEED TO ADD
TEMPO THERE SHOULD A BROKEN LINE OF CONVECTION DEVELOP SO WILL
MONITOR TRENDS. ANY STORM LATE THIS AFTERNOON/EVENING WILL BE
CAPABLE OF PRODUCING BRIEF IFR CONDITIONS ALONG WITH STRONG WIND
GUSTS. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 330 AM EDT THU MAY 17 2012/
DISCUSSION...S FLA HAS BEEN UNDER THE INFLUENCE OF THE UPPER TROUGH
OVER THE E U.S. COAST THAT CURRENTLY EXTENDS SW ACROSS THE SE U.S.
INTO THE GULF OF MEX. TODAY AND INTO THE WEEKEND...A CLOSED LOW WILL
DEVELOP OVER THE SE U.S./ADJACENT ATLC AND WILL PERSIST THROUGH THE
WEEKEND INTO EARLY NEXT WEEK DUE TO THE DEVELOPMENT OF A REX BLOCK
AS A STRONG UPPER RIDGE EXTENDS NW OVER NEW ENGLAND FROM THE ALTC
HIGH. THIS STOPS THE MOVEMENT OF THE UPPER LOW. BY MIDWEEK NEXT
WEEK...LONG RANGE MODELS DIFFER SOME ON THE SCENARIO...BUT A DEEP
UPPER TROUGH OVER THE WESTERN U.S. MOVES E WHICH PULLS THE CLOSED
LOW N AND ABSORBING THE FORMER SYSTEM. THE GFS INDICATES MULTIPLE
SMALL UPPER TROUGHS THAT MAY CROSS FLA WITH THE ECMWF INDICATING A
WESTERLY FLOW ALOFT WHICH MAY BRING MINIMAL SHORT WAVES ACROSS THE
AREA.
SHORT TERM...(TODAY-SATURDAY)...TODAY COULD BE MORE ACTIVE THAN
THURSDAY. A 500 MB 40 KT WIND AXIS MOVES NE ACROSS S CENTRAL FLA
WITH S FLA IN THE RFQ WITH SOME SPEED DIVERGENCE. WITH E/W COAST SEA
BREEZES DEVELOPING ALONG WITH THE AMPLE POSSIBILITY OF MORE
INSOLATION...VERY HIGH POPS WITH NUMEROUS TO WIDESPREAD
SHOWERS/THUNDERSTORMS POSSIBLE INTERIOR AND E. THERE WILL BE MAINLY
EVENING SHOWERS/THUNDERSTORMS E THIS EVENING BUT WITH THE MOIST
SW FLOW...ACTIVITY WILL STILL MOVE FROM THE GULF ACROSS THE
PENINSULA. POPS DIFFER BETWEEN MODELS FRIDAY BUT THE SURFACE
TROUGH...WHICH IS A REFLECTION OF THE UPPER TROUGH TO THE
NW...REMAINS NW OF S FLA AND S FLA REMAINS UNDER THE VERY MOIST
REGIME LIKE TODAY. THUS...WILL GO ABOVE MAV POPS. FRIDAY NIGHT A
SW FLOW ALOFT REMAINS BUT WITH THE SURFACE TROUGH DRAGGING
THROUGH...POPS LOWER. ON SATURDAY...SOME DRYING OCCURS.
EXTENDED PERIOD...(SUNDAY-WEDNESDAY)...AS MENTIONED ABOVE...THE
LONG RANGE PATTERN VARIES PER MODEL AND SOME DECREASE IN CONFIDENCE
OF THE POSSIBILITIES EXISTS. WITH THE SW UPPER FLOW PROJECTED TO
PERSIST...SOME RIPPLES MOVING THROUGH AND WITH VARIATION ON MODEL
PRECIPITATION FORECAST...WILL FOLLOW MEX GUIDANCE BUT EXPECT MORE
ACTIVITY IN THE INTERIOR AND NE THROUGH THE PERIOD AS THE LOW LEVEL
EASTERLY FLOW EXPECTED SHUNTING PRECIPITATION A BIT TO THE N.
MARINE...
WINDS GENERALLY LESS THAN 10 KNOTS WITH AND SEAS 3 FEET OR LESS. THE
MAIN PROBLEMS WILL BE THE SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS.
FIRE WEATHER...
AMPLE RAIN AND HIGH HUMIDITY EQUAL NO PROBLEMS TODAY AND THROUGH THE
WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 84 72 86 72 / 70 50 50 40
FORT LAUDERDALE 85 74 87 75 / 70 50 50 40
MIAMI 85 73 88 74 / 70 50 50 40
NAPLES 83 71 85 70 / 50 50 50 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...15/JR
AVIATION/RADAR...17/ERA
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
113 PM EDT THU MAY 17 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 140 AM EDT THU MAY 17 2012
HIGH PRESSURE OVER THE APPALACHIANS WILL DOMINATE INDIANA WEATHER
THROUGH THE WEEKEND. A COLD FRONT IS FORECAST TO APPROACH AND THEN
CROSS THE HOOSIER STATE MONDAY AND TUESDAY. AFTER THAT...HIGH
PRESSURE SHOULD RETURN FROM THE WEST.
&&
.NEAR TERM /TODAY/...
ISSUED AT 1010 AM EDT THU MAY 17 2012
NO SIGNIFICANT CHANGES NEEDED AT THIS TIME. MADE SOME CHANGES TO
THE DEWPOINT GRIDS TO LOWER THEM ACROSS THE SOUTH AS SOME DRY
ADVECTION OCCURRING. PREVIOUS FORECAST HAD LEANED TOWARDS WARMER MAV
AND THIS SEEMS REASONABLE GIVEN THERE WILL BE FULL SUNSHINE TODAY.
THE RUC MODEL SOUNDINGS WERE A LITTLE WARMER WHILE THE 00Z NAM
SOUNDINGS WERE A LITTLE COOLER. MADE A FEW MINOR TWEAKS TO
TEMPERATURE GRIDS MAINLY TO LOWER THEM A DEGREE IN THE EAST.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 140 AM EDT THU MAY 17 2012
ALL MODELS CLOSE..BUT NAM IS A MINOR OUTLIER COMPARED TO NEARLY
IDENTICAL SREF AND GFS. WITH GFS LOOKING A LITTLE BETTER WILL USE
THAT AS UNDERLYING MODEL.
THIS DOES NOT MAKE MUCH DIFFERENCE SINCE ALL MODELS CALLING FOR
MOSTLY CLEAR THROUGH SATURDAY AND MET AND MAV ARE CLOSE ON TEMPS.
USING MAV WHEN ANY DIFFERENCE FROM MET BECAUSE FAVOR GFS AND MAV
HAD LONGER DEVELOPMENT CYCLE.
PRECIP NOT ABSOLUTELY OUT OF QUESTION SATURDAY NIGHT IN WARM
ADVECTION. HOWEVER POSSIBILITY IS MARGINAL AT MOST AND WILL
CONTINUE WITH DRY FORECAST FOR NOW.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 220 AM EDT THU MAY 17 2012
MAIN FOCUS ON THE LONG TERM WILL BE TIMING OF THUNDERSTORM CHANCES
BACK TO CENTRAL INDIANA ALONG WITH TEMPERATURES AS A COLD FRONT
APPROACHES LATE IN THE WEEKEND AND EARLY NEXT WEEK.
THE 00Z GEM IS NOW LEANING SLOWER WITH A COLD FRONT LATE THIS
WEEKEND AND EARLY NEXT WEEK PER THE 12Z ECMWF AND EURO TRENDS AND AS
OPPOSED TO THE FASTER 00Z GFS AND GFS TRENDS. THIS WOULD FAVOR
HOLDING OFF POPS INTIL SUNDAY NIGHT ACROSS THE WEST AND ACROSS ALL
OF CENTRAL INDIANA BY MONDAY. THE FRONT AND ASSOCIATED CONVECTION
ARE EXPECTED TO RESULT IN NOT AS WARM TEMPERATURES BY MONDAY WITH
REASONABLE CR INIT HIGHS ONLY IN THE 70S BY TUESDAY WITH 80S SUNDAY
AND MONDAY AHEAD OF THE FRONT. INSTABILITY PROGS SUGGEST PLENTY OF
INSTABILITY THROUGH THE PERIOD FOR THUNDERSTORM MENTION.
&&
.AVIATION /DISCUSSION FOR THE 17/1800Z TAF ISSUANCE/...
ISSUED AT 104 PM EDT THU MAY 17 2012
VFR CONDITIONS EXPECTED FOR ENTIRE TAF PERIOD WITH HIGH PRESSURE
STILL IN CONTROL OVER TAF SITES. WILL NOT INSERT ANY FOG FOR
TONIGHT...MODELS ARE NOT INDICATING ANY FORMATION. WINDS WILL BE
EASTERLY AT 4 TO 8 KTS THROUGH THIS EVENING...AND WILL THEN
DECREASE TO 2 TO 4 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JH
LONG TERM....MK
AVIATION...TDUD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1043 AM EDT THU MAY 17 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 140 AM EDT THU MAY 17 2012
HIGH PRESSURE OVER THE APPALACHIANS WILL DOMINATE INDIANA WEATHER
THROUGH THE WEEKEND. A COLD FRONT IS FORECAST TO APPROACH AND THEN
CROSS THE HOOSIER STATE MONDAY AND TUESDAY. AFTER THAT...HIGH
PRESSURE SHOULD RETURN FROM THE WEST.
&&
.NEAR TERM /TODAY/...
ISSUED AT 1010 AM EDT THU MAY 17 2012
NO SIGNIFICANT CHANGES NEEDED AT THIS TIME. MADE SOME CHANGES TO
THE DEWPOINT GRIDS TO LOWER THEM ACROSS THE SOUTH AS SOME DRY
ADVECTION OCCURRING. PREVIOUS FORECAST HAD LEANED TOWARDS WARMER MAV
AND THIS SEEMS REASONABLE GIVEN THERE WILL BE FULL SUNSHINE TODAY.
THE RUC MODEL SOUNDINGS WERE A LITTLE WARMER WHILE THE 00Z NAM
SOUNDINGS WERE A LITTLE COOLER. MADE A FEW MINOR TWEAKS TO
TEMPERATURE GRIDS MAINLY TO LOWER THEM A DEGREE IN THE EAST.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 140 AM EDT THU MAY 17 2012
ALL MODELS CLOSE..BUT NAM IS A MINOR OUTLIER COMPARED TO NEARLY
IDENTICAL SREF AND GFS. WITH GFS LOOKING A LITTLE BETTER WILL USE
THAT AS UNDERLYING MODEL.
THIS DOES NOT MAKE MUCH DIFFERENCE SINCE ALL MODELS CALLING FOR
MOSTLY CLEAR THROUGH SATURDAY AND MET AND MAV ARE CLOSE ON TEMPS.
USING MAV WHEN ANY DIFFERENCE FROM MET BECAUSE FAVOR GFS AND MAV
HAD LONGER DEVELOPMENT CYCLE.
PRECIP NOT ABSOLUTELY OUT OF QUESTION SATURDAY NIGHT IN WARM
ADVECTION. HOWEVER POSSIBILITY IS MARGINAL AT MOST AND WILL
CONTINUE WITH DRY FORECAST FOR NOW.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 220 AM EDT THU MAY 17 2012
MAIN FOCUS ON THE LONG TERM WILL BE TIMING OF THUNDERSTORM CHANCES
BACK TO CENTRAL INDIANA ALONG WITH TEMPERATURES AS A COLD FRONT
APPROACHES LATE IN THE WEEKEND AND EARLY NEXT WEEK.
THE 00Z GEM IS NOW LEANING SLOWER WITH A COLD FRONT LATE THIS
WEEKEND AND EARLY NEXT WEEK PER THE 12Z ECMWF AND EURO TRENDS AND AS
OPPOSED TO THE FASTER 00Z GFS AND GFS TRENDS. THIS WOULD FAVOR
HOLDING OFF POPS INTIL SUNDAY NIGHT ACROSS THE WEST AND ACROSS ALL
OF CENTRAL INDIANA BY MONDAY. THE FRONT AND ASSOCIATED CONVECTION
ARE EXPECTED TO RESULT IN NOT AS WARM TEMPERATURES BY MONDAY WITH
REASONABLE CR INIT HIGHS ONLY IN THE 70S BY TUESDAY WITH 80S SUNDAY
AND MONDAY AHEAD OF THE FRONT. INSTABILITY PROGS SUGGEST PLENTY OF
INSTABILITY THROUGH THE PERIOD FOR THUNDERSTORM MENTION.
&&
.AVIATION /DISCUSSION FOR THE 17/1500Z TAF UPDATE/...
ISSUED AT 1041 AM EDT THU MAY 17 2012
UPDATE...
NO CHANGES.
PREVIOUS DISCUSSION...
VFR CONDITIONS EXPECTED TODAY WITH JUST SOME HIGH CLOUDS LATE. CU
PROGS WERE NOT INDICATING ANY DIURNAL CU. WOULD NOT RULE OUT FOG
OVERNIGHT TONIGHT WITH MODELS AGREEING ON DEW POINTS INCREASING TO
THE UPPER 40S AS HIGH PRESSURE SHIFTS TO THE EASTERN GREAT LAKES
ALLOW FOR LIGHT SOUTHEAST ATLANTIC FETCH OF MOISTURE. HOWEVER...MOS
IS NOT INDICATING ANY YET...SO WILL HOLD OFF FOR NOW DESPITE EAST
WINDS NEAR 10 KNOTS TODAY BECOMING LIGHT TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JH
LONG TERM....MK
AVIATION...MK/TDUD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1010 AM EDT FRI MAY 17 2012
.UPDATE...
NEAR TERM FR THE REST OF TODAY HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 140 AM EDT THU MAY 17 2012
HIGH PRESSURE OVER THE APPALACHIANS WILL DOMINATE INDIANA WEATHER
THROUGH THE WEEKEND. A COLD FRONT IS FORECAST TO APPROACH AND THEN
CROSS THE HOOSIER STATE MONDAY AND TUESDAY. AFTER THAT...HIGH
PRESSURE SHOULD RETURN FROM THE WEST.
&&
.NEAR TERM /TODAY/...
ISSUED AT 1010 AM EDT THU MAY 17 2012
NO SIGNIFICANT CHANGES NEEDED AT THIS TIME. MADE SOME CHANGES TO
THE DEWPOINT GRIDS TO LOWER THEM ACROSS THE SOUTH AS SOME DRY
ADVECTION OCCURRING. PREVIOUS FORECAST HAD LEANED TOWARDS WARMER MAV
AND THIS SEEMS REASONABLE GIVEN THERE WILL BE FULL SUNSHINE TODAY.
THE RUC MODEL SOUNDINGS WERE A LITTLE WARMER WHILE THE 00Z NAM
SOUNDINGS WERE A LITTLE COOLER. MADE A FEW MINOR TWEAKS TO
TEMPERATURE GRIDS MAINLY TO LOWER THEM A DEGREE IN THE EAST.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 140 AM EDT THU MAY 17 2012
ALL MODELS CLOSE..BUT NAM IS A MINOR OUTLIER COMPARED TO NEARLY
IDENTICAL SREF AND GFS. WITH GFS LOOKING A LITTLE BETTER WILL USE
THAT AS UNDERLYING MODEL.
THIS DOES NOT MAKE MUCH DIFFERENCE SINCE ALL MODELS CALLING FOR
MOSTLY CLEAR THROUGH SATURDAY AND MET AND MAV ARE CLOSE ON TEMPS.
USING MAV WHEN ANY DIFFERENCE FROM MET BECAUSE FAVOR GFS AND MAV
HAD LONGER DEVELOPMENT CYCLE.
PRECIP NOT ABSOLUTELY OUT OF QUESTION SATURDAY NIGHT IN WARM
ADVECTION. HOWEVER POSSIBILITY IS MARGINAL AT MOST AND WILL
CONTINUE WITH DRY FORECAST FOR NOW.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 220 AM EDT THU MAY 17 2012
MAIN FOCUS ON THE LONG TERM WILL BE TIMING OF THUNDERSTORM CHANCES
BACK TO CENTRAL INDIANA ALONG WITH TEMPERATURES AS A COLD FRONT
APPROACHES LATE IN THE WEEKEND AND EARLY NEXT WEEK.
THE 00Z GEM IS NOW LEANING SLOWER WITH A COLD FRONT LATE THIS
WEEKEND AND EARLY NEXT WEEK PER THE 12Z ECMWF AND EURO TRENDS AND AS
OPPOSED TO THE FASTER 00Z GFS AND GFS TRENDS. THIS WOULD FAVOR
HOLDING OFF POPS INTIL SUNDAY NIGHT ACROSS THE WEST AND ACROSS ALL
OF CENTRAL INDIANA BY MONDAY. THE FRONT AND ASSOCIATED CONVECTION
ARE EXPECTED TO RESULT IN NOT AS WARM TEMPERATURES BY MONDAY WITH
REASONABLE CR INIT HIGHS ONLY IN THE 70S BY TUESDAY WITH 80S SUNDAY
AND MONDAY AHEAD OF THE FRONT. INSTABILITY PROGS SUGGEST PLENTY OF
INSTABILITY THROUGH THE PERIOD FOR THUNDERSTORM MENTION.
&&
.AVIATION /DISCUSSION FOR 171200Z TAF ISSUANCE/...
ISSUED AT 617 AM EDT WED MAY 17 2012
VFR CONDITIONS EXPECTED TODAY WITH JUST SOME HIGH CLOUDS LATE. CU
PROGS WERE NOT INDICATING ANY DIURNAL CU. WOULD NOT RULE OUT FOG
OVERNIGHT TONIGHT WITH MODELS AGREEING ON DEW POINTS INCREASING TO
THE UPPER 40S AS HIGH PRESSURE SHIFTS TO THE EASTERN GREAT LAKES
ALLOW FOR LIGHT SOUTHEAST ATLANTIC FETCH OF MOISTURE. HOWEVER...MOS
IS NOT INDICATING ANY YET...SO WILL HOLD OFF FOR NOW DESPITE EAST
WINDS NEAR 10 KNOTS TODAY BECOMING LIGHT TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JH
LONG TERM....MK
AVIATION...MK
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1110 PM MDT WED MAY 16 2012
.UPDATE...
ISSUED AT 827 PM MDT WED MAY 16 2012
MAIN UPDATE WAS TO REMOVE THREAT OF THUNDERSTORMS FROM EASTERN
COLORADO TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 150 PM MDT WED MAY 16 2012
EARLY AFTERNOON WV IMAGERY AND RUC H5 ANALYSIS SHOW SHORTWAVE RIDGE
OVER WESTERN KS BEGINNING TO BREAK DOWN AS SHORTWAVE TROUGH OVER
GREAT BASIN CONTINUES TO MOVE EAST INTO THE CENTRAL ROCKIES. TIGHT
GRADIENT CURRENTLY IN PLACE ACROSS CWA NO EASTERN EXTENT OF LEE
TROUGH HAS LED TO BREEZY CONDITIONS ACROSS THE AREA...WITH WINDS
GUSTING AROUND 30KT AT SEVERAL LOCATIONS. A WARM FRONT JUST
SOUTHWEST OF GOODLAND LIFTING TO THE NORTHEAST. WEST OF THIS FRONT
RH VALUES HAVE DROPPED TO 15% OR LOWER. WITH SEVERAL LOCATIONS
ALREADY WITHIN RED FLAG CRITERIA...PLAN ON KEEPING RFW IN PLACE
THROUGH EXPIRATION (02Z).
SHORTWAVE TROUGH WILL CONTINUE TO MOVE EAST WITH LARGE SCALE ASCENT
SPREADING INTO EASTERN COLORADO. RADAR RETURNS ALREADY SHOWING
SHOWERS/THUNDERSTORMS ALONG FRONT RANGE...WITH ACTIVITY GENERALLY
MOVING FROM THE SOUTH TO NORTH. LATEST RUC/HRRR SHOW THIS ACTIVITY
REMAINING JUST EAST OF THE CWA. WITH LARGE SCALE ASCENT STILL
EXPECTED TO OVERSPREAD THE CWA...AND THE CLOSE PROXIMITY OF
ACTIVITY...I DECIDED TO LEAVE ISOLATED THUNDERSTORMS IN FORECAST
THIS EVENING.
SHORTWAVE TROUGH AXIS CURRENTLY PROGGED TO MOVE EAST ACROSS WESTERN
KS. GUIDANCE IN GENERAL AGREEMENT ON TIMING...HOWEVER STRENGTH AND
POSITION OF SHORTWAVE ARE STILL ISSUES...WITH KEEPING OUR CWA
DRY...AND OTHER GUIDANCE FAVORING THE SOUTH AND EAST LATE THURSDAY
AFTERNOON. WITH INSTABILITY/LARGE SCALE ASCENT ACROSS THE CWA
THURSDAY...SLIGHT CHANCE POPS FROM PREVIOUS FORECAST SEEMED
REASONABLE. TIGHT SURFACE GRADIENT WILL REMAIN IN PLACE OVER EASTERN
PARTS OF CWA...WITH NAM/GFS BL WINDS APPROACHING ADVISORY CRITERIA
FOR A PERIOD OF TIME THURSDAY AFTERNOON. CONFIDENCE IS NOT THERE
THAT ADVISORY CRITERIA WINDS WILL LAST 3HR...SO NO HAZARD PLANNED.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 248 PM MDT WED MAY 16 2012
THURSDAY EVENING THE SHORT WAVE TROUGH WILL CONTINUE TO MOVE EAST
ACROSS THE AREA. LATEST GUIDANCE DISAGREES WITH THE LOCATION OF THE
SHORT WAVE TROUGH DURING THE EVENING...WITH THE GFS SHIFTING THE
TROUGH FURTHER NORTH WHILE THE NAM HAS KEPT THE TROUGH OVER THE
SOUTHERN PART OF THE AREA. WITH MODELS NOT BEING CONSISTENT WITH
THE PLACEMENT OF THE SHORT WAVE TROUGH...WILL EXPAND THE SLIGHT
CHANCES TO INCLUDE THE ENTIRE AREA EAST OF THE COLORADO LINE. WITH
A DEEP WELL MIXED LAYER IN PLACE OVER THE AREA...STRONG DOWN BURST
WINDS WILL BE POSSIBLE WITH ANY THUNDERSTORM THAT DEVELOPS DURING
THE EARLY EVENING. THE SHORT WAVE TROUGH AND MID LEVEL CAPE WILL
EXIT THE AREA AROUND MIDNIGHT BRINGING ANY CHANCE FOR PRECIPITATION
TO AN END.
FRIDAY A DRY LINE SETS UP OVER THE CENTRAL PART OF THE AREA. DURING THE
MID TO LATE AFTERNOON A SHORT WAVE TROUGH MOVES OVER THE DRY LINE.
POINT SOUNDINGS FOR THE AREA SHOW THE ENVIRONMENT NEARING SATURATION
AROUND THE 500MB LEVEL ON UP...SO AM THINKING THE STORM DEVELOPMENT
WILL BE TIED TO THE LOCATION OF THE 500MB LIFT. HOWEVER CANNOT RULE
OUT ENOUGH CONVERGENCE OCCURRING OVER THE DRY LINE FOR A STORM OR TWO
TO INITIATION...SO HAVE PLACED SLIGHT CHANCES ALONG THE DRY LINE WITH
FOCUS ON THE BETTER AREA OF 500MB LIFT DURING THE LATE
AFTERNOON. WITH THE DEEP WELL MIXED ENVIRONMENT OVER THE
AREA...STRONG DOWN BURST WINDS ARE POSSIBLE WITH ANY STORM THAT
DEVELOPS DURING THE EARLY EVENING. THE SHORT WAVE TROUGH EXITS THE
AREA AROUND MIDNIGHT...BRINGING PRECIPITATION CHANCES TO AN END.
SOUTH WINDS WILL INCREASE DURING THE LATE MORNING AND AFTERNOON AS
STRONGER WINDS ABOVE THE SURFACE MIX DOWN TO THE GROUND. THE
SURFACE PRESSURE GRADIENT WILL ALSO TIGHTEN THROUGH THE AFTERNOON
AHEAD OF THE COLD FRONT THAT WILL MOVE THROUGH DURING THE OVERNIGHT
HOURS. WINDS WILL PEAK DURING THE LATE AFTERNOON...WITH GUSTS UP TO
40 MPH POSSIBLE. THE WINDS WILL EASE SOME DURING THEN EVENING AS
MIXING CEASES...BUT WILL STILL BE GUSTY DUE TO THE TIGHT PRESSURE
GRADIENT IN PLACE AHEAD OF THE COLD FRONT.
DURING THE OVERNIGHT HOURS A COLD FRONT WILL MOVE INTO THE AREA FROM
THE NORTHWEST. LATEST CROSS SECTIONS SHOW THE LIFT TO BE SITUATED
AHEAD OF THE FRONT IN THE DRIER AIR. WILL BE KEEPING THE FRONTAL
PASSAGE FOR THE OVERNIGHT PERIOD DRY AS A RESULT.
THE SATURDAY THROUGH FRIDAY PERIOD WILL START OFF WITH PRECIPITATION
CHANCES ACROSS MOST OF THE AREA SATURDAY...FOLLOWING A SHORT WAVE
TROUGH AND COLD FRONT THAT WILL MOVE THROUGH THE AREA DURING THE
DAY. BULK OF THE MOISTURE WILL BE OVER THE NORTHERN HALF OF THE
AREA...CAUSING PRECIPITATION CHANCES TO QUICKLY DECREASE OVER THE
SOUTHERN PART OF THE AREA THAT WILL BE IN THE DRIER AIR. BEHIND THE
FRONT WINDS WILL BE GUSTY...BUT SHOULD DECLINE THROUGH THE DAY AS
THE FRONT MOVES FURTHER SOUTH.
SATURDAY EVENING PRECIPITATION CHANCES CONTINUE AS THE SHORT WAVE
TROUGH MOVES ACROSS THE EASTERN PART OF THE AREA. MODELS HAVE A
SECOND SHORT WAVE TROUGH FOLLOWING THE FIRST ONE OVER THE WESTERN
PART OF THE AREA. AM NOT TOO CONFIDENT THERE WILL BE MUCH MOISTURE
FOR THE SECOND SHORT WAVE TO WORK WITH...BUT KEPT IN SLIGHT CHANCES
FOR THE REST OF THE AREA TO STAY CONSIST ANT WITH NEIGHBORS.
PRECIPITATION CHANCES RETURN WEDNESDAY TO THE EASTERN PART OF THE
AREA AS ANOTHER SHORT WAVE TROUGH MOVES ACROSS THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1106 PM MDT WED MAY 16 2012
VFR EXPECTED THROUGH THE PERIOD AT KGLD AND KMCK. MID AND HIGH
LEVEL CLOUDS WILL BE PREVALENT AHEAD OF AN UPPER LEVEL TROUGH THAT
WILL MOVE ACROSS THE TERMINALS DURING AFTERNOON AND EARLY EVENING
HOURS BEFORE EXITING THE AREA TOWARD THE END OF THE TAF PERIOD. A
FEW THUNDERSTORMS ARE EXPECTED WITH THE TROUGH PASSAGE AND BEST
GUESS IS AFTER 21Z. GIVEN THE ISOLATED NATURE WILL NOT INCLUDE A
CB MENTION AT PRESENT TIME. SOUTH WINDS AROUND 20 KTS WITH HIGHER
GUSTS EXPECTED AT KMCK AROUND 18Z-02Z.
&&
.FIRE WEATHER...
ISSUED AT 248 PM MDT WED MAY 16 2012
FRIDAY AFTERNOON SOUTH WINDS WILL STRENGTHEN...WITH GUSTS UP TO 40
MPH ACROSS THE AREA. RELATIVE HUMIDITIES WILL FALL INTO THE 10 TO
20 PERCENT RANGE DURING THE AFTERNOON FOR LOCATIONS WEST OF A
MCCOOK TO GOVE LINE...LEADING TO HAZARDOUS FIRE WEATHER
CONDITIONS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...007
SHORT TERM...DR
LONG TERM...JTL
AVIATION...DDT
FIRE WEATHER...JTL
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1244 PM EDT THU MAY 17 2012
.Forecast Update...
Issued at 1135 AM EDT May 17 2012
The clouds that were moving in from the northeast earlier this
morning dissipated right on schedule, leaving us with mostly sunny
skies by 15Z.
Surface dew points have been increasing and pooling over southern
Kentucky this morning. HRRR has been trending much more bullish
with convection in the south this afternoon. After coordination
with neighboring offices, and considering the afternoon development
we saw over the past two days, have decided to go ahead and throw in
a SLGT CHC of showers/storms during peak heating this afternoon in
the south. Will restrict PoPs to the south of where the 1000 foot
overcast was earlier.
Issued at 830 AM EDT May 17 2012
This update primarily dealt with a 1000 foot overcast that developed
over the southern Blue Grass. It appears that the clouds should mix
out by 15Z, but in the meantime we have significantly increased
cloudcover in and near that patch of clouds.
A shower managed to pop up over Hart County between 11Z and 12Z but
it has since fallen apart. Munfordville web cam did show some
elevated instability revealed in the cumuliform cloud structures
overhead...as also seen on visible satellite channel. A rogue
shower will still be possible in southeastern sections of the LMK
CWA near a diffuse cold front, but coverage should remain minimal.
Went ahead an increased PoPs to a silent 13% southeast of a BWG-LEX
line.
.Short Term (Today through Friday)...
Issued at 308 AM EDT May 17 2012
The weak frontal boundary that brought scattered showers/storms to
the region last evening has stalled across south-central KY early
this morning. South of this boundary, winds are calm and dewpoints
are still in the upper 50s. With this moist air in place, light
ground fog will again be possible towards dawn, mainly over lakes or
low-lying areas or river valleys. North of the boundary however,
winds are out of the northeast with dewpoints dropping into the
upper 40s. Even further north, a secondary dewpoint boundary across
southern IN has upper 30 dewpoints behind it. Needless to say, high
pressure over the Great Lakes is on the way. This surface high will
push south and bring drier air into the region through the
short-term period. Only hang up will be added cloud cover near the
stalled boundary across the TN/KY border. Think this boundary will
eventually push south into TN today, so precip should remain south
of our CWA with dry weather forecast.
With clear skies for the most part today, think we`ll be able to
reach the upper 70s northeast into the lower 80s southwest. With
high pressure continuing on Friday and even more dry air in place,
good mixing and veering winds will allow for temps to climb even
higher, with low to mid 80s being the rule under sunny skies again.
Lows tonight will drop into the low to mid 50s with no fog expected.
.Long Term (Friday Night through Wednesday)...
Issued at 250 AM EDT May 17 2012
A mostly dry and quite warm weekend is setting up for the region as
we remain under the influence of surface high pressure and an upper
level ridge. Regarding precip chances Saturday and Sunday afternoon,
there is still a lot of uncertainty as to whether any storms will
be able to develop. The GFS continues to develop some precip, though
it now paints the best chance on Sunday across the entire are, with
less on Saturday. The ECMWF remains dry and we will continue to
advertise a dry solution for now, though pops may be needed at some
point in time. With southerly winds and mostly sunny skies under the
high pressure, temperatures will be quite warm this weekend. Highs
will top out in the mid to upper 80s with lows in the lower 60s.
A front will begin to approach the region on Monday and move through
Monday night into Tuesday. Isolated to scattered thunderstorms will
develop ahead of this front on Monday. Storm coverage will increase
Monday night and Tuesday as the front passes through the area.
Beyond Tuesday the forecast is a bit less certain. The GFS is much
faster than the ECMWF at clearing things out behind the front as the
ECMWF is slower to move out an upper level low. There is quite a bit
of spread in the ensembles on precip chances for Wednesday, so will
carry a slight chance of shower/storms for now. With increased
cloud/precip coverage Monday through Wednesday, high temperatures
will be a bit cooler, in the upper 70s to lower 80s. Lows will
continue to drop into the lower 60s.
&&
.Aviation (18Z TAF Issuance)...
Updated at 1244 PM EDT May 17 2012
High pressure moving by to the north will keep our skies mostly
clear through the TAF period. A stray storm or two may pop up
around BWG this afternoon but chances of the airport getting hit are
very slim at this point.
BWG avoided any sub-VFR fog this morning, and it appears that will
be the case again Friday morning.
Northeast breezes today will go calm tonight and veer slightly to
the east and southeast tomorrow though they will remain light.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........13
Short Term.......AL
Long Term........EER
Aviation.........13
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1135 AM EDT THU MAY 17 2012
.Forecast Update...
Issued at 1135 AM EDT May 17 2012
The clouds that were moving in from the northeast earlier this
morning dissipated right on schedule, leaving us with mostly sunny
skies by 15Z.
Surface dew points have been increasing and pooling over southern
Kentucky this morning. HRRR has been trending much more bullish
with convection in the south this afternoon. After coordination
with neighboring offices, and considering the afternoon development
we saw over the past two days, have decided to go ahead and throw in
a SLGT CHC of showers/storms during peak heating this afternoon in
the south. Will restrict PoPs to the south of where the 1000 foot
overcast was earlier.
Issued at 830 AM EDT May 17 2012
This update primarily dealt with a 1000 foot overcast that developed
over the southern Blue Grass. It appears that the clouds should mix
out by 15Z, but in the meantime we have significantly increased
cloudcover in and near that patch of clouds.
A shower managed to pop up over Hart County between 11Z and 12Z but
it has since fallen apart. Munfordville web cam did show some
elevated instability revealed in the cumuliform cloud structures
overhead...as also seen on visible satellite channel. A rogue
shower will still be possible in southeastern sections of the LMK
CWA near a diffuse cold front, but coverage should remain minimal.
Went ahead an increased PoPs to a silent 13% southeast of a BWG-LEX
line.
.Short Term (Today through Friday)...
Issued at 308 AM EDT May 17 2012
The weak frontal boundary that brought scattered showers/storms to
the region last evening has stalled across south-central KY early
this morning. South of this boundary, winds are calm and dewpoints
are still in the upper 50s. With this moist air in place, light
ground fog will again be possible towards dawn, mainly over lakes or
low-lying areas or river valleys. North of the boundary however,
winds are out of the northeast with dewpoints dropping into the
upper 40s. Even further north, a secondary dewpoint boundary across
southern IN has upper 30 dewpoints behind it. Needless to say, high
pressure over the Great Lakes is on the way. This surface high will
push south and bring drier air into the region through the
short-term period. Only hang up will be added cloud cover near the
stalled boundary across the TN/KY border. Think this boundary will
eventually push south into TN today, so precip should remain south
of our CWA with dry weather forecast.
With clear skies for the most part today, think we`ll be able to
reach the upper 70s northeast into the lower 80s southwest. With
high pressure continuing on Friday and even more dry air in place,
good mixing and veering winds will allow for temps to climb even
higher, with low to mid 80s being the rule under sunny skies again.
Lows tonight will drop into the low to mid 50s with no fog expected.
.Long Term (Friday Night through Wednesday)...
Issued at 250 AM EDT May 17 2012
A mostly dry and quite warm weekend is setting up for the region as
we remain under the influence of surface high pressure and an upper
level ridge. Regarding precip chances Saturday and Sunday afternoon,
there is still a lot of uncertainty as to whether any storms will
be able to develop. The GFS continues to develop some precip, though
it now paints the best chance on Sunday across the entire are, with
less on Saturday. The ECMWF remains dry and we will continue to
advertise a dry solution for now, though pops may be needed at some
point in time. With southerly winds and mostly sunny skies under the
high pressure, temperatures will be quite warm this weekend. Highs
will top out in the mid to upper 80s with lows in the lower 60s.
A front will begin to approach the region on Monday and move through
Monday night into Tuesday. Isolated to scattered thunderstorms will
develop ahead of this front on Monday. Storm coverage will increase
Monday night and Tuesday as the front passes through the area.
Beyond Tuesday the forecast is a bit less certain. The GFS is much
faster than the ECMWF at clearing things out behind the front as the
ECMWF is slower to move out an upper level low. There is quite a bit
of spread in the ensembles on precip chances for Wednesday, so will
carry a slight chance of shower/storms for now. With increased
cloud/precip coverage Monday through Wednesday, high temperatures
will be a bit cooler, in the upper 70s to lower 80s. Lows will
continue to drop into the lower 60s.
&&
.Aviation (06Z TAF Issuance)...
Updated at 645 AM EDT May 17 2012
The weak cold front is still located across south-central KY. Based
on BWG`s pressure, it may be just south of that location. Winds will
remain light and variable at BWG for another 1-2 hours with a light
haze, as well. Otherwise, this boundary will slowly sag southward,
possibly leading to a stray shower near the BWG terminal through
18z. Will keep BWG dry though due to limited coverage. North of this
boundary, LEX and SDF will continue to have decent northeasterly
winds today (8-12 knots on average) with a few higher gusts. Expect
FEW mid-level clouds at those terminals through midday with clear
skies thereafter. With the front nearby, more SCT cloud coverage
will affect BWG with cloud bases from 6-12kft.
Tonight, skies will clear at all locations as winds veer a little to
the east, not quite tapering off to calm overnight.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........13
Short Term.......AL
Long Term........EER
Aviation.........13
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
1008 PM EDT FRI MAY 18 2012
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE FOR DRY WEATHER WITH A WARMING TREND
CONTINUING THROUGH THE WEEKEND. THE CHANCE OF SHOWERS AND
THUNDERSTORMS WILL RETURN ON MONDAY AS A FRONTAL BOUNDARY
APPROACHES FROM THE WEST.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
NO CHANGES TO PREVIOUS FORECAST, EVERYTHING IS ON TRACK.
PREVIOUS DISCUSSION...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A 500MB RIDGE AXIS
EXTENDING FROM THE ARKLATEX REGION INTO THE LOWER GREAT LAKES. AT
THE SURFACE, A 1025MB HIGH IS CENTERED ACROSS NEW ENGLAND AND
EXTENDS SOUTHWESTWARD INTO THE UPPER OHIO VALLEY. MEANWHILE, A
CLOSED LOW IS DEVELOPING OFF THE CAROLINA COAST.
THE 500MB RIDGE WILL BUILD IN FURTHER INTO THE GREAT LAKES REGION
TODAY AND TONIGHT WITH WEAK ANTI-CYCLONIC FLOW ALOFT CENTERED ACROSS
NORTHERN OHIO BY 12Z SATURDAY. THIS WILL ALLOW ABUNDANT SUNSHINE TO
CONTINUE INTO THE EVENING. WITH NEAR CALM WINDS AND CLEAR SKIES
TONIGHT, RADIATIONAL COOLING WILL ALLOW FOR TEMPERATURES TO
STEADILY DROP OFF. OVERNIGHT LOWS WILL RANGE FROM THE LOWER 40S
ACROSS THE I-80 CORRIDOR AND EASTERN RIDGES TO THE LOWER 50S
ACROSS PORTIONS OF EASTERN OHIO AND NORTH-CENTRAL WV. WITH SUPPORT
FROM THE LAMP, PATCHY RADIATION FOG IS FORECAST TO DEVELOP
OVERNIGHT ACROSS THE SOUTHEAST RIDGES.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
THERE IS ECMWF/GFS AGREEMENT THAT THE RIDGE WILL CONTINUE TO BUILD
NORTHEASTWARD WITH ITS AXIS CENTERED ACROSS THE AREA ON SUNDAY. THIS
WILL ALLOW FOR DRY WEATHER TO CONTINUE SATURDAY THROUGH MOST OF
SUNDAY. SOME UNCERTAINTY ENTERS THE FORECAST LATE SUNDAY, AS THE UPPER
LOW BEGINS TO RETROGRADE. THIS HAS BEEN ACCOUNTED FOR WITH SCHC
POPS ACROSS THE SOUTHEAST RIDGES. WITH GFS 850MB TEMPS WARMING TO
14-16C, HIGHS ON SATURDAY AND SUNDAY ARE 10 TO 15 DEGREES ABOVE
NORMAL WITH MANY LOWLAND LOCATIONS WARMING INTO THE MID 80S.
AROUND 30 DEGREE DIURNAL RANGES ARE ANTICIPATED AS A WEAK FLOW
WITH DRY AIR ALLOWS FOR STRONG RADIATIONAL COOLING EACH NIGHT.
RIDGING WILL BECOME PINCHED OFF AS THE CLOSED LOW ACROSS THE
CAROLINAS CONTINUES TO RETROGRADE AND A TROUGH MOVES INTO THE GREAT
LAKES ON MONDAY. THIS WILL ALLOW FOR ATLANTIC-STREAM MOISTURE TO
FILTER INTO THE AREA WITH MORE HUMID CONDITIONS ANTICIPATED. IN
ADDITION, A FRONTAL BOUNDARY WILL APPROACH FROM THE WEST LATE ON
MONDAY. MOISTURE WILL CONTRIBUTE TO INCREASING INSTABILITY AND
THUS THE CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS THE AREA
MONDAY AFTERNOON. INCREASING CLOUDINESS WILL LIMIT TEMPS SLIGHTLY
ON MONDAY, WITH HIGHS STILL AROUND 10 DEGREES ABOVE NORMAL.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
MODELS CONTINUE TO DISAGREE SOMEWHAT WITH REGARD TO TIMING OF THE
FRONT APPROACHING FROM THE WEST AND ON THE EXTENT OF
RETROGRESSION OF EAST COAST LOW EARLY NEXT WEEK.
STAYED CLOSE TO HPC GUIDANCE WHICH STILL LEANS TOWARD FASTER GFS
TIMING WITH THE FRONT AND PUSHES THE MAIN AREA OF PRECIPITATION
EAST OF THE REGION BY WEDNESDAY NIGHT.
A WEAK SURFACE RIDGE SHOULD PROVIDE GENERALLY DRY WEATHER FOR
THURSDAY INTO FRIDAY FOR MUCH OF THE FORECAST AREA. MOIST SOUTHEAST
FLOW FROM THE ATLANTIC DEPICTED BY THE ECMWF COULD MAINTAIN
SCATTERED PRECIPITATION OVER THE RIDGES ON THURSDAY NIGHT AND
FRIDAY.
TEMPERATURES ARE FORECAST TO RANGE FROM 5 TO 10 DEGREES ABOVE NORMAL
THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS AND LIGHT EAST WINDS WILL PREVAIL THROUGH THE TAF
PERIOD AS A SURFACE RIDGE HOLDS ALONG THE APPALACHIANS.
.OUTLOOK...SATURDAY NIGHT THROUGH WEDNESDAY...
THE SURFACE RIDGE WILL MAINTAIN VFR WEATHER THROUGH SUNDAY NIGHT.
A FRONT WILL APPROACH FROM THE WEST LATE MONDAY WHILE A LOW
PRESSURE SYSTEM MOVES INLAND FROM THE CAROLINA COAST. MOISTURE
WILL INCREASE ACROSS THE REGION BY LATE MONDAY ALONG WITH THE
POTENTIAL FOR RESTRICTIONS IN SHOWERS AND THUNDERSTORMS. SCATTERED
PRECIPITATION SHOULD PERSIST THROUGH WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
358 PM EDT THU MAY 17 2012
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER THE NORTHEASTERN STATES WHILE LOW
PRESSURE MOVES SLOWLY NORTH OFF THE CAROLINA COAST THROUGH THE
WEEKEND.
&&
.NEAR TERM /THROUGH FRIDAY/...
THE COLD FRONT HAS PUSHED TO SOUTH INTO THE CAROLINAS AS SURFACE
HIGH PRESSURE OVER THE EASTERN GREAT LAKES BEGINS TO INFLUENCE THE
REGION. UPPER LEVEL LOW PRESSURE WAS SPINNING OVER EASTERN GEORGIA.
NORTHEAST WINDS HAVE KEPT CLOUDS (BASES 1 TO 3K FT) OVER PORTIONS OF
SE VIRGINIA AND NE NORTH CAROLINA. SHOWERS APPEAR TO HAVE ENDED OVER
OUR AREA AS DRIER AIR MOVES IN ALOFT.
WILL KEEP CONSIDERABLE CLOUDINESS OVER FAR SOUTHEAST PORTIONS AND
THE REST OF THE AREA WILL GRADUALLY CLEAR. LOW TEMPERATURES WILL
RANGE FROM AROUND 50 OVER THE MD LOWER EASTERN SHORE AND THE
NORTHERN PIEDMONT TO NEAR 60 ON THE SRN VA/NC COAST.
HIGH PRESSURE REMAINS ANCHORED ACROSS THE NORTHEAST U.S. ON FRIDAY.
MEANWHILE...THE AFOREMENTIONED COLD FRONT STALLS OFF THE SOUTHEAST
COAST. LOW PRESSURE FORMS ALONG THIS FRONTAL BOUNDARY OVER THE
WESTERN ATLANTIC. THE COMBINATION OF HIGH PRESSURE TO THE NORTH AND
LOW PRESSURE OFF THE COAST WILL RESULT IN PERSISTENT ONSHORE FLOW.
THIS WILL MAINTAIN PLEASANT HIGH TEMPERATURES WITH READINGS RANGING
FROM THE LOW 70S ALONG THE COAST TO THE UPPER 70S OVER THE PIEDMONT.
ON FRIDAY...SKIES WILL BE MOSTLY CLEAR WELL INLAND BUT MOSTLY CLOUDY
ACROSS SOUTHEAST VA AND NORTHEAST NORTH CAROLINA. THERE WILL BE A
SLIGHT CHANCE FOR RAIN OVER A SMALL PORTION OF OUR NORTH CAROLINA
COUNTIES NEAR THE COAST..
HIGH TEMPERATURES WILL RANGE FROM THE MID TO UPPER 60S NEAR THE
COAST TO THE MID TO UPPER 70S WELL INLAND.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
UNCERTAINTY CONTINUES FOR THE UPCOMING WEEKEND DUE TO QUESTIONS
SURROUNDING THE PROGRESS OF THE SYSTEM IN THE SOUTHEAST. SOME
GUIDANCE RETROGRADES THE LOW TO THE WEST OVER THE CAROLINAS AND THEN
DISSIPATES. THIS SOLUTION WOULD BRING WET WEATHER TO THE AREA THIS
WEEKEND. IT DOESN`T APPEAR THAT BLOCKING TO THE NORTH WOULD BE
STRONG ENOUGH FOR THIS TO OCCUR.
HPC PREFERS THE TREND OF THE EURO AND GFS WITH KEEPING THE LOW
OFFSHORE AND THUS A RELATIVELY DRY SOLUTION FOR THE MID ATLANTIC
STATES. THE EURO SEEMS TO BE FAIRLY CONSISTENT AND APPEARS RIGHT NOW
TO HAVE THE BEST HANDLE ON IT.
THE RESULT IS SLIGHT CHANCE OF RAIN NEAR THE NORTH CAROLINA COAST
FRIDAY NIGHT INCREASING TO A 30 PERCENT CHANCE OF RAIN BY SATURDAY
NIGHT. SLIGHT CHANCE POPS SPREADS INTO SOUTHEAST VIRGINIA BY
SATURDAY NIGHT AND TO OUR ENTIRE AREA ON SUNDAY. IN SUMMARY...MOST
OF THE AREA IS FORECAST TO BE DRY THIS WEEKEND. RESIDENTS ESPECIALLY
NEAR THE COAST SHOULD CONTINUE TO MONITOR THE LATEST FORECAST FOR
UPDATES.
GENERALLY DID A BLEND OF NAM AND MAV GUIDANCE AND BLENDED IT WITH
MOS GUIDE FOR TEMPERATURES. THERE IS A SIGNIFICANT DIFFERENCE WITH
HIGH TEMPERATURES SATURDAY BETWEEN THE MET AND MAV DUE TO A
VARIATION IN FORECAST CLOUD COVER (THE MAV BEING 10 OR MORE DEGREES
WARMER THAN THE MET ACROSS INLAND AREAS.
HIGH TEMPERATURES SATURDAY AND SUNDAY ARE FORECAST TO BE IN THE 70S
EXCEPT UPPER 60S NEAR THE COAST (POSSIBLY COOLER IF RAIN DEVELOPS).
LOWS IN THE MID TO UPPER 40S WEST OF INTERSTATE 95 SATURDAY MORNING
(DUE TO MOSTLY CLEAR SKIES) WILL RANGE TO THE MID 50S TOWARD THE
COAST. LOWS SUNDAY MORNING ARE FORECAST TO BE IN THE 50S ACROSS THE
AREA.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
BROAD UPR-LVL TROF REMAINS IN PLACE OVR THE EASTERN SEABOARD INTO
ERLY NEXT WEEK LEADING TO A TRICKY FORECAST SCENARIO. VARIOUS
SHORTWAVES PIVOTING AROUND THE TROF WILL LEAD TO SFC LOW DEVELOPMENT
OFFSHORE...WITH MODELS CONTINUING TO DIFFER ON THE TIMING AND
STRENGTH OF THESE SFC LOWS. 12Z ECMWF BRINGS A LOW UP THE EASTERN
SEABOARD MON INTO TUE LEADING TO A BETTER CHC FOR RAIN (ESPECIALLY
OVR EASTERN AREAS) THAN THE 12Z GFS WHICH STALLS THE SFC LOW NEAR
THE SOUTH CAROLINA COAST MON AND TUE. WILL CAP POPS AT 30% FOR NOW.
THE BROAD UPR-LVL TROF WILL BE REINFORCED INTO THE MIDDLE OF NEXT
WEEK AS PLENTY OF ENERGY SLIDES DOWN THE WESTERN HALF OF THE TROF
FROM THE RIDGE OVR THE HIGH PLAINS. SO WILL MAINTAIN SLGT CHC TO CHC
POPS FOR THE REMAINDER OF THE LONG TERM PERIOD. TEMPS WILL BE
SEASONABLE...HIGHS GENERALLY IN THE UPR 70S TO LWR 80S.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
COLD FRONT HAS MOVED SOUTH OF THE AREA EARLY THIS AFTERNOON. CAN
SEE ON VWP THAT WINDS HAVE SHIFTED TO NE THRU AT LEAST 7 THOUSAND
FEET. THIS IS BRINGING SOME MOISTURE FROM OFF THE ATLANTIC AND
WITH COOLING TEMPERATURES GETTING SOME CLOUD FORMATION GENERALLY
AROUND 2 THOUSAND FEET. THIS IS WELL DEPICTED BY RH AT 925 MB ON
THE RAP MODEL. WILL USE THE TIMING FROM THE RAP TO SCATTERED THE
CLOUDS FROM NORTH TO SOUTH AROUND SUNRISE. SBY ALREADY HAS DRY AIR
COMING IN AND THIS IS KEEPING CLOUDS SCATTERED THERE.
MODELS ALL HAVE DIFFERING SOLUTIONS WITH CUTOFF LOW TO THE SOUTH
OF THE AREA AND THIS IMPACTS MOISTURE FEED OFF THE ATLANTIC. THE
NAM BRINGS LOW CLOUDS BACK AS EARLY AS FRIDAY MORNING BUT NONE OF
THE OTHER MODELS DO. WHILE FEEL WITH FLOW OFF THE WATER COULD HAVE
AT LEAST SOME SCATTERED CLOUDS SO WENT AROUND 3 THOUSAND SCATTERED.
AS THE WEEKEND PROGRESSES MORE MOISTURE WILL COME IN FROM THE
ATLANTIC AND CEILINGS WILL BECOME MVFR AND POTENTIALLY DOWN TO IFR
BY LATE IN THE WEEKEND. WITH DIFFERENT TIMINGS FROM THE MODELS
THERE IS STILL A LOT OF UNCERTAINTY ON THE TIMING OF THESE CONDITIONS.
&&
.MARINE...
HI PRES WILL CONTINUE TO BLD OVR THE MID ATLANTIC THIS EVNG
FOLLOWING THE COLD FROPA EARLIER TDY. THIS WILL LEAD TO PERSISTENT
ONSHORE FLOW AND INCREASING EASTERLY SWELL CAUSING 5 FT SEAS OVR
COASTAL WATERS OVRNGT. SCA HEADLINES ALSO IN EFFECT OVR THE
BAY/SOUND/LWR JAMES RIVER WHERE NE WNDS WILL INCREASE OVRNGT. DUE
TO UNCERTAINTY REGARDING START TIME OF REACHING SCA WNDS...THESE
WNDS EXPECTED WITHIN 12 HR...AND HEADLINES ALREADY IN
PLACE...DECIDED TO PUT THE SCA INTO EFFECT WITH THIS FORECAST
PACKAGE. OTHER THREE MARINE ZONES (OVR THE RIVERS) MAY NEED TO BE
INCLUDED AS WELL AT SOME POINT. NE WNDS INCREASE FRI AND FRI NGT AS
LO PRES MOVES UP THE SE COAST WHILE HI PRES HOLDS STEADY OVR THE
NE...LEADING TO A TIGHTENING PRES GRADIENT. FAVORED SREF/ECMWF
REGARDING WND DIRECTION WITH THIS SYSTM. WILL END THE HEADLINES
UP FOR WNDS SAT MRNG DUE TO UNCERTAINTY REGARDING THE TRACK OF THE
LOW PRES SYSTM. SEAS EXPECTED TO STAY AOA 5 FT THRU THE DAY SAT.
&&
.EQUIPMENT...
ASOS OBSERVATION FOR PHF IS NOT AVAILABLE ONLINE DUE TO COMMS
ISSUE. THE PROBLEM IS BEING WORKED ON AND RTS IS NOT KNOWN AT THIS
TIME.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EDT SATURDAY FOR ANZ630>634-
638.
SMALL CRAFT ADVISORY UNTIL 7 PM EDT SATURDAY FOR ANZ650-652-
654-656-658.
&&
$$
SYNOPSIS...LSA
NEAR TERM...LSA
SHORT TERM...LSA
LONG TERM...MAS
AVIATION...JAB
MARINE...MAS
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
145 PM EDT THU MAY 17 2012
.SYNOPSIS...
HIGH PRESSURE OVER THE GREAT LAKES BUILDS IN FROM THE NORTHWEST
TODAY BEHIND A COLD FRONT AND BECOMES ANCHORED OVER THE NORTHEAST
FROM FRIDAY THROUGH THE WEEKEND. MEANWHILE...THE COLD FRONT STALLS
OFF THE SOUTHEAST COAST. LOW PRESSURE DEVELOPS ALONG THIS FRONT AND
MEANDERS OVER THE WESTERN ATLANTIC THROUGH THE WEEKEND WITH MUCH
UNCERTAINTY WITH RESPECT TO THE EVENTUAL TRACK OF THE SYSTEM.
&&
.NEAR TERM /THROUGH FRIDAY/...
EARLY AFTN UPDATE INCREASED CLOUD COVER FOR TODAY AS WIDESPREAD
CUMULUS HAS FORMED. HIGH CLOUDS ARE ALSO CONTRIBUTING TO THE CLOUD
COVER. ALSO INCLUDED SLGT CHC THUNDER IN PORTIONS OF THE NORTH
CAROLINA COUNTIES.
ONSHORE WINDS ARE KEEPING SURFACE DEW POINTS RATHER HIGH IN THE
SOUTHEAST AND MOST INLAND AREAS HAVE READINGS IN THE UPPER 50S TO
LOWER 60S. THIS IS RESULTING IN A LOW LCL OF 15 TO 25 HUNDRED FEET
(THUS THE CUMULUS) ACRS SRN AND EASTERN SECTIONS OF THE CWA.
THE HIGHER DEW POINTS ARE HELPING TO PRODUCE WIDELY SCATTERED
CONVECTIVE SHOWERS AND ISOLATED TSTMS OVER PORTIONS OF THE NORTH
CAROLINA COUNTIES. DRYING ALOFT SHOULD KEEP ANY TSTMS TO A MINIMUM
AND ARE EXPECTED TO END BY 20Z.
THE COLD FRONT HAS PUSHED SOUTH OF THE AREA AS OF 14Z. DEW POINTS
ARE STILL IN THE 60S TO AROUND 70 OVER MOST OF THE AREA BUT SHOULD
FALL INTO THE UPR 40S TO LWR 50S OVER NORTHERN SECTIONS BY THIS
AFTN.
CLOUDS WILL KEEP HIGH TEMPERATURES GENERALLY IN THE 70S WITH
ONSHORE FLOW HOLDING AFTERNOON TEMPERATURES NEAR THE COAST IN THE
UPPER 60S. WARMEST READINGS WILL BE IN THE MID TO UPR 70S.
FROM PREVIOUS DISCUSSION... HIGH PRESSURE SHOULD CONTINUE TO
PREVAIL TONIGHT. THE SKY SHOULD RANGE FROM MOSTLY CLEAR OVER MOST
OF THE AREA TO PARTLY CLOUDY OVER COASTAL NE NC. LOW TEMPERATURES
ARE EXPECTED TO RANGE FROM THE UPPER 40S N...TO THE MID TO UPPER
50S OVER EXTREME SE VA AND COASTAL NE NC.
HIGH PRESSURE REMAINS ANCHORED ACROSS THE NORTHEAST US ON FRIDAY.
MEANWHILE...THE AFOREMENTIONED COLD FRONT STALLS OFF THE SOUTHEAST
COAST. LOW PRESSURE FORMS ALONG THIS FRONTAL BOUNDARY OVER THE
WESTERN ATLANTIC. THE COMBINATION OF HIGH PRESSURE TO THE NORTH AND
LOW PRESSURE OFF THE COAST WILL RESULT IN PERSISTENT ONSHORE FLOW.
THIS WILL MAINTAIN PLEASANT HIGH TEMPERATURES WITH READINGS RANGING
FROM THE LOW 70S ALONG THE COAST TO THE UPPER 70S OVER THE PIEDMONT.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
THERE IS MUCH UNCERTAINTY FOR THE UPCOMING WEEKEND. INDIVIDUAL MODEL
SOLUTIONS HAVE LARGELY BEEN CONSISTENT FROM RUN-TO-RUN...BUT
INCONSISTENT AMONGST EACH OTHER WITH RESPECT TO THE EVENTUAL TRACK
OF THE AFOREMENTIONED AREA OF LOW PRESSURE OFF THE WESTERN ATLANTIC.
THE NAM AND GEM GLOBAL MOVE THE LOW PRESSURE SYSTEM NORTHWARD OFF
THE OUTER BANKS BEFORE RETROGRADING IT WESTWARD INTO THE MID
ATLANTIC OVER THE WEEKEND. THIS WOULD LEAD TO WET CONDITIONS
ESPECIALLY ALONG THE COAST. THE ECMWF IS SLOWER WITH WITH ANY
MOISTURE NOT ARRIVING UNTIL LATER IN THE WEEKEND AND EARLY NEXT
WEEK. MEANWHILE...THE GFS IS MOST OPTIMISTIC WITH HIGH PRESSURE
PREVAILING THROUGH THE WEEKEND. ADDITIONALLY THE SREF MEAN IS MORE
IN LINE WITH THE NAM/GEM. CHANCE POPS WILL BE FORECAST FOR SE
COASTAL LOCATIONS THROUGH THE WEEKEND ALONG WITH INCREASED SKY COVER
MAINLY ALONG THE COAST. ONSHORE FLOW WILL KEEP HIGHS IN THE
70S...BUT IF RAIN DOES MOVE OVER THE COAST HIGHS WILL BE COOLER.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
BROAD UPR-LVL TROF REMAINS IN PLACE OVR THE EASTERN SEABOARD INTO
ERLY NEXT WEEK SO WILL KEEP SLGT CHC/LOW CHC POPS IN THE FORECAST.
HIGH TEMPERATURES APPEAR TO WARM INTO THE LOW 80S BY THE MIDDLE OF
NEXT WEEK.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
COLD FRONT HAS MOVED SOUTH OF THE AREA EARLY THIS AFTERNOON. CAN
SEE ON VWP THAT WINDS HAVE SHIFTED TO NE THRU AT LEAST 7 THOUSAND
FEET. THIS IS BRINGING SOME MOISTURE FROM OFF THE ATLANTIC AND
WITH COOLING TEMPERATURES GETTING SOME CLOUD FORMATION GENERALLY
AROUND 2 THOUSAND FEET. THIS IS WELL DEPICTED BY RH AT 925 MB ON
THE RAP MODEL. WILL USE THE TIMING FROM THE RAP TO SCATTERED THE
CLOUDS FROM NORTH TO SOUTH AROUND SUNRISE. SBY ALREADY HAS DRY AIR
COMING IN AND THIS IS KEEPING CLOUDS SCATTERED THERE.
MODELS ALL HAVE DIFFERING SOLUTIONS WITH CUTOFF LOW TO THE SOUTH
OF THE AREA AND THIS IMPACTS MOISTURE FEED OFF THE ATLANTIC. THE
NAM BRINGS LOW CLOUDS BACK AS EARLY AS FRIDAY MORNING BUT NONE OF
THE OTHER MODELS DO. WHILE FEEL WITH FLOW OFF THE WATER COULD HAVE
AT LEAST SOME SCATTERED CLOUDS SO WENT AROUND 3 THOUSAND SCATTERED.
AS THE WEEKEND PROGRESSES MORE MOISTURE WILL COME IN FROM THE
ATLANTIC AND CEILINGS WILL BECOME MVFR AND POTENTIALLY DOWN TO IFR
BY LATE IN THE WEEKEND. WITH DIFFERENT TIMINGS FROM THE MODELS
THERE IS STILL A LOT OF UNCERTAINTY ON THE TIMING OF THESE CONDITIONS.
&&
.MARINE...
COLD FRONT HAS NOW PUSHED SOUTH OF THE AREA. WITH THE LOW LEVEL
FLOW COMING OUT OF THE NE AND TEMPERATURES COOLING GETTING A DECK
OF CLOUDS BETWEEN 2 AND 3 THOUSAND FEET OVER MUCH OF THE AREA.
THIS IS COLD FRNT WILL PUSH THRU THE MARINE AREA FM N TO S THRU
THIS MORNG...WITH LGT SSW WNDS SHIFTING TO THE NNE AND INCREASING
TO 15 TO 20 KT. WILL HAVE SCA FOR THE CHES BAY DURING TDY...THEN
HAVE SCA FOR THE SRN TWO CHES BAY ZNS...CURRITUCK SND...AND ALL
THE CSTL ZNS FM LATE THIS AFTN THRU LATE FRI NGT...AS NE WNDS 15
TO ARND 20 KT PRODUCES WAVES 3 TO 4 FT IN THE SRN CHES BAY...AND
SEAS 5 TO 6 FT OVR THE CSTL ZNS. THIS NE FLO WILL RESULT FM HI
PRES BLDNG BY TO THE N AND LO PRES LINGERING OFF THE MID ATLC CST.
&&
.EQUIPMENT...
ASOS OBSERVATION FOR PHF IS NOT AVAILABLE ONLINE DUE TO COMMS
ISSUE. THE PROBLEM IS BEING WORKED ON AND RTS IS NOT KNOWN AT THIS
TIME.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EDT SATURDAY FOR ANZ632-634.
SMALL CRAFT ADVISORY UNTIL 7 AM EDT SATURDAY FOR ANZ633-650-
652-654-656-658.
SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR ANZ630-
631.
&&
$$
SYNOPSIS...AJZ
NEAR TERM...AJZ/LSA
SHORT TERM...AJZ
LONG TERM...MAS
AVIATION...JAB
MARINE...TMG
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
149 PM EDT THU MAY 17 2012
.SYNOPSIS...
ISSUED AT 512 AM EDT THU MAY 17 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM
THE PLAINS INTO CNTRL CANADA AND A DOWNSTREAM TROUGH FROM QUEBEC
INTO THE NE CONUS RESULTING IN NW FLOW THROUGH THE NRN GREAT LAKES.
AT THE SFC...HIGH PRES WAS CENTERED OVER LOWER MI WHILE LOW PRES WAS
DEVELOPING OVER THE PLAINS FROM SRN SASK INTO WRN SOUTH DAKOTA. MID
LEVEL WARM ADVECTION AHEAD OF A WARM FRONT OVER THE CNTRL PLAINS
SUPPORTED DEVELOPING SHRA AND A FEW TSRA OVER SW MN.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 512 AM EDT THU MAY 17 2012
TODAY...EXPECT THE BAND OF STRONGER 310K ISENTROPIC LIFT AND
POSITION OF THE 750-650 MB WARM FRONT TO EXPAND TO THE ENE
TODAY...PER NAM/GFS. HOWEVER...SINCE THE PCPN IS MOVING AWAY FROM
THE GREATER LOW LEVEL MOISTURE INTO THE DRY LOW LEVEL AIRMASS TO THE
EAST...PER 00Z MPX/INL/GRB SOUNDINGS...THE PCPN SHOULD REMAIN LIGHT
AND MAINLY TO THE WEST AND SOUTH OF THE CWA. LOCATIONS FROM IWD-IMT
WILL SEE THE BEST CHANCE OF ANY PCPN BUT ONLY SLIGHT CHANCE POPS
WERE INCLUDED WITH ANY PCPN AMOUNTS LESS THAN A TENTH OF AN INCH.
OTHERWISE...WAA WILL HELP PUSH TEMPS INTO THE MID 50S TO LOWER 70S
DESPITE AN INCREASE IN MID HIGH CLOUDS.
TONIGHT...THE FOCUS OF THE LLJ AND STRONGEST MOISTURE TRANSPORT IS
EXPECTED OVER NE MN AND NW WI INTO WRN LAKE SUPERIOR. AREAS OF
SHRA/TSRA SHOULD DEVELOP AND EVENTUALLY SPREAD TO THE EAST AFFECTING
MAINLY THE NW HALF OF THE CWA AS THE LLJ VEERS OVERNIGHT.
HOWEVER...THERE IS STILL SIGNIFICANT UNCERTAINTY WITH THE
TIMING/POSITION OF THE CONVECTION.
FRIDAY...ANY LEFTOVER SHRA/TSRA OVER MAINLY NORTH UPPER MI INTO LAKE
SUPERIOR SHOULD SLIDE TO THE ENE AND DIMINISH DURING THE MORNING AS
THE LLJ WEAKENS. THE COMBINATION OF BUILDING MID-LVL RDG HEIGHTS AND
850 MB WARM FRONT LIFTING WELL NORTH OF THE AREA SHOULD KEEP THE CWA
DRY FRI AFTERNOON. RESIDUAL CLOUDS FROM CONVECTION SHOULD DISSIPATE
FRI AFTERNOON ALLOWING FOR INCREASED SUNSHINE. MIXING OF 850 MB
TEMPS OF AROUND 16C TO THE SFC SHOULD ALLOW FOR HIGH TEMPS FRIDAY TO
REACH INTO THE LOWER 80S OVER WRN INTERIOR LOCATION. COOLER SRLY
FLOW OFF LAKE MI WILL KEEP INLAND HIGHS OVER ERN COUNTIES IN THE LOW
TO MID 70S.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 512 AM EDT THU MAY 17 2012
PERIOD STARTS 00Z SAT WITH A 500MB RIDGE OVER THE CWA...AND A 500MB
TROUGH OVER THE INTERMOUNTAIN WEST. AT THE SFC...994MB LOW PRESSURE
WILL BE STRETCHED E FROM ERN CO TO SRN ND...AND WITH HIGH PRESSURE
SITTING OVER THE ERN SEABOARD...THAT PUTS US UNDER S/SSW FLOW.
THAT/S RIGHT...WE WILL BE IN THE WARM SECTOR AS THE WARM FRONT
ASSOCIATED WITH THE SYSTEM TO OUR W WILL BE N OF LAKE SUPERIOR BY 00Z
SAT. AND WARM IT WILL BE WITH 850MB TEMPS AROUND 17C.
FRI NIGHT AND SAT...SOLID S/SW FLOW IN THE WARM LOW LEVELS WILL KEEP
TEMPS FROM FALLING TOO FAR FRI NIGHT...ESPECIALLY IN DOWNSLOPING
AREAS. HAVE LOW TEMPS AROUND 60 IN THE DOWNSLOPE AREAS...AND IN THE
UPPER 40S TO 50S ELSEWHERE. WITH HIGHER DEW PTS AND WAA...COULD SEE
FOG OVER MAINLY NRN LAKE SUPERIOR AND EVENTUALLY NRN LAKE MI /WHICH
WOULD LAST UNTIL FROPA SUNDAY/...WHICH I ADDED TO THE FORECAST FOR
FRI NIGHT THROUGH SUN. 850MB TEMPS STAY AROUND 17C THROUGH
SAT...WITH GOOD S/SW FLOW CONTINUING...ALLOWING MIXING TO AROUND
800MB. THIS YIELDS HIGH TEMPS IN THE 80S OVER THE W HALF AND NEAR
LAKE SUPERIOR OVER THE E HALF...WITH HIGHS IN THE 60S CLOSE TO NRN
LAKE MI DUE TO S/SSW FLOW OF THE RELATIVELY COLD LAKE. ATMOSPHERE
LOOKS TOO DRY AND TOO CAPPED FOR CONVECTION TO FORM ON SAT...WHICH
IS GOOD SINCE WE SHOULD HAVE 1500-2000J/KG OF CAPE SAT AFTERNOON.
LOWERED DEW PTS A FEW DEGREES AS MIXING WILL ALLOW DRY AIR TO GET TO
THE SFC. THIS LEADS TO MIN RH VALUES DOWN OF 25 TO 35 PERCENT OVER
THE W HALF OF UPPER MI...AND GREATER THAN 35 PERCENT RH OVER THE E
HALF. THIS BECOMES MORE PROBLEMATIC WHEN CONSIDERING WINDS WILL BE
SLY AT 15-20MPH WITH GUSTS OF 25-35MPH. LOOKS LIKE IT MAY BE A
CRITICAL FIRE WEATHER DAY...BUT THAT WILL NEED TO BE LOOKED AT MORE
CLOSELY BY LATER SHIFTS FOR POSSIBLE FIRE WEATHER HEADLINES.
SAT NIGHT THROUGH MON...BY 00Z SUN...THE UPPER TROUGH WILL HAVE MOVED
FARTHER E...WITH A SHORTWAVE TROUGH OVER MANITOBA...AND POSSIBLY
ANOTHER OVER KS/NE. THE SFC LOW WILL HAVE WEAKENED TO 1002MB AS IT
MOVED TO N OF THE MN ARROWHEAD. THIS PUTS THE COLD JUST W OF LAKE
SUPERIOR AT 00Z SUN. SAT NIGHT WILL BE ANOTHER WARM ONE WITH
CONTINUED STRONG LOW LEVEL FLOW AND WARM LOW LEVEL TEMPS. OVERNIGHT
LOWS LOOK TO BE IN THE 50S AND LOW 60S. DIFFERING MODEL SOLUTIONS
BEGIN TO LOWER CONFIDENCE ON EXACT TIMING OF THE COLD FRONT/PRECIP
DUE MAINLY WITH HOW TO HANDLE A SHORTWAVE MOVING AROUND THE MAIN
UPPER TROUGH SAT NIGHT INTO SUN. THE GFS CONTINUES TO BE THE MOST
AGGRESSIVE WITH THE SHORTWAVE...SHOWING IT STRONGER THAN PRETTY MUCH
ANY OTHER MODEL. THIS MEANS THE GFS ALSO BRINGS THE COLD FRONT
THROUGH FASTER THAN OTHER MODELS. FOR THIS REASON...WILL NOT PUT AS
MUCH OF THE GFS INTO THIS FORECAST. WITH THE IDEA THAT THE GFS IS
ABOUT 6 HOURS TOO FAST WITH FROPA...THE FRONT SHOULD MOVE OVER WRN
UPPER MI SUN AFTERNOON...AND MOVE TO ERN UPPER MI BY 12Z MON...NOTE
THE SLOW EASTWARD PROGRESSION OF THE FRONT. SBCAPES OF AROUND
1000-1500J/KG WILL BE POSSIBLE SUN AFTERNOON AHEAD OF THE
FRONT...BUT CONFIDENCE IN THIS IS A BIT LOW RIGHT NOW DUE TO MODEL
TIMING DIFFERENCES AND UNCERTAINTY IN HOW MUCH CLEARING WILL OCCUR
AHEAD OF THE FRONT. 0-6KM BULK SHEAR LOOKS TO BE AROUND
30KTS...SUFFICIENT FOR ORGANIZED CONVECTION. SO...IT LOOKS LIKE SOME
STRONG TO SEVERE STORMS WILL BE A POSSIBILITY SUN
AFTERNOON/EVENING...BUT CONFIDENCE IS STILL LIMITED. THE COLD FRONT
LOOKS TO COMPLETELY CLEAR THE CWA AROUND 18Z MON...AS THE UPPER
TROUGH AND A SFC RIDGE MOVE INTO THE WRN CWA. 850MB TEMPS OF AROUND
7C MON AFTERNOON WILL MAKE FOR COOLER TEMPS IN THE 60S...EXCEPT IN
THE 50S NEAR LAKE SUPERIOR IN THE NLY WINDS.
MON NIGHT THROUGH WED...EXPECT A GRADUAL WARMING TREND AS AN UPPER
RIDGE MOVES OVERHEAD AND SFC RIDGING SLOWLY MOVES TO E OF THE CWA BY
WED AFTERNOON.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 148 PM EDT THU MAY 17 2012
WARM FRONT OVER SOUTHERN MINNESOTA WILL LIFT THROUGH UPPER MICHIGAN
LATE TONIGHT AND INTO LK SUPERIOR AND ONTARIO BY LATE DAY FRIDAY.
MAY SEE SHOWERS AS THE FRONT MOVES THROUGH...BUT AIR MASS OVER UPR
MICHIGAN IS QUITE DRY SO THINK COVERAGE WILL REMAIN SCATTERED. BEST
CHANCE FOR RAIN IS EARLY THIS AFTN AT IWD AND OVERNIGHT TONIGHT AT
CMX. ISOLD TSRA MAY OCCUR TONIGHT AT IWD AND CMX...BUT CONFIDENCE IS
TOO LOW TO PUT INTO FCST. MAIN HAZARD AT ALL TAF SITES TONIGHT IS
LOW LEVEL WIND SHEAR AS SOUTHWEST LOW-LEVEL JET UP TO 45 KTS MOVES
OVER THE AREA. SFC WINDS WILL BE GENERALLY LIGHT AND MAINLY SOUTH OR
SOUTH-SOUTHEAST DIRECTION SO THERE WILL BE SOME DIRECTIONAL SHEAR AS
WELL. ANY LLWS WILL END AROUND SUNRISE FRIDAY. GUSTY SW WINDS WILL
DEVELOP FRIDAY AS MID CLOUDS SCATTER OUT. GIVEN THE DRY AIR OVR THE
REGION...EVEN IF SHRA/TSRA OCCUR...EXPECT VFR CONDITIONS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 512 AM EDT THU MAY 17 2012
WINDS ACROSS LAKE SUPERIOR SHOULD REMAIN BELOW 30KTS THROUGH THE
PERIOD. HIGH PRESSURE ACROSS THE UPPER GREAT LAKES WILL SHIFT TO THE
LOWER GREAT LAKES THIS AFTERNOON...BEFORE PUSHING OFF THE MID
ATLANTIC SHORELINE ON FRIDAY INTO SATURDAY. LOW PRESSURE OVER
SOUTHERN SASKATCHEWAN AND THE WESTERN DAKOTAS WILL PUSH ACROSS THE
NORTHERN AND CENTRAL PLAINS TONIGHT THROUGH SATURDAY...BEFORE
SLIDING NORTH INTO ONTARIO SATURDAY. THIS WILL ALLOW A COLD FRONT TO
PUSH ACROSS THE UPPER GREAT LAKES SUNDAY INTO EARLY MONDAY. BEHIND
THE FRONT...HIGH PRESSURE WILL BUILD IN FROM THE CENTRAL AND
NORTHERN PLAINS THROUGH TUESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLA
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
730 AM EDT THU MAY 17 2012
.SYNOPSIS...
ISSUED AT 512 AM EDT THU MAY 17 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM
THE PLAINS INTO CNTRL CANADA AND A DOWNSTREAM TROUGH FROM QUEBEC
INTO THE NE CONUS RESULTING IN NW FLOW THROUGH THE NRN GREAT LAKES.
AT THE SFC...HIGH PRES WAS CENTERED OVER LOWER MI WHILE LOW PRES WAS
DEVELOPING OVER THE PLAINS FROM SRN SASK INTO WRN SOUTH DAKOTA. MID
LEVEL WARM ADVECTION AHEAD OF A WARM FRONT OVER THE CNTRL PLAINS
SUPPORTED DEVELOPING SHRA AND A FEW TSRA OVER SW MN.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 512 AM EDT THU MAY 17 2012
TODAY...EXPECT THE BAND OF STRONGER 310K ISENTROPIC LIFT AND
POSITION OF THE 750-650 MB WARM FRONT TO EXPAND TO THE ENE
TODAY...PER NAM/GFS. HOWEVER...SINCE THE PCPN IS MOVING AWAY FROM
THE GREATER LOW LEVEL MOISTURE INTO THE DRY LOW LEVEL AIRMASS TO THE
EAST...PER 00Z MPX/INL/GRB SOUNDINGS...THE PCPN SHOULD REMAIN LIGHT
AND MAINLY TO THE WEST AND SOUTH OF THE CWA. LOCATIONS FROM IWD-IMT
WILL SEE THE BEST CHANCE OF ANY PCPN BUT ONLY SLIGHT CHANCE POPS
WERE INCLUDED WITH ANY PCPN AMOUNTS LESS THAN A TENTH OF AN INCH.
OTHERWISE...WAA WILL HELP PUSH TEMPS INTO THE MID 50S TO LOWER 70S
DESPITE AN INCREASE IN MID HIGH CLOUDS.
TONIGHT...THE FOCUS OF THE LLJ AND STRONGEST MOISTURE TRANSPORT IS
EXPECTED OVER NE MN AND NW WI INTO WRN LAKE SUPERIOR. AREAS OF
SHRA/TSRA SHOULD DEVELOP AND EVENTUALLY SPREAD TO THE EAST AFFECTING
MAINLY THE NW HALF OF THE CWA AS THE LLJ VEERS OVERNIGHT.
HOWEVER...THERE IS STILL SIGNIFICANT UNCERTAINTY WITH THE
TIMING/POSITION OF THE CONVECTION.
FRIDAY...ANY LEFTOVER SHRA/TSRA OVER MAINLY NORTH UPPER MI INTO LAKE
SUPERIOR SHOULD SLIDE TO THE ENE AND DIMINISH DURING THE MORNING AS
THE LLJ WEAKENS. THE COMBINATION OF BUILDING MID-LVL RDG HEIGHTS AND
850 MB WARM FRONT LIFTING WELL NORTH OF THE AREA SHOULD KEEP THE CWA
DRY FRI AFTERNOON. RESIDUAL CLOUDS FROM CONVECTION SHOULD DISSIPATE
FRI AFTERNOON ALLOWING FOR INCREASED SUNSHINE. MIXING OF 850 MB
TEMPS OF AROUND 16C TO THE SFC SHOULD ALLOW FOR HIGH TEMPS FRIDAY TO
REACH INTO THE LOWER 80S OVER WRN INTERIOR LOCATION. COOLER SRLY
FLOW OFF LAKE MI WILL KEEP INLAND HIGHS OVER ERN COUNTIES IN THE LOW
TO MID 70S.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 512 AM EDT THU MAY 17 2012
PERIOD STARTS 00Z SAT WITH A 500MB RIDGE OVER THE CWA...AND A 500MB
TROUGH OVER THE INTERMOUNTAIN WEST. AT THE SFC...994MB LOW PRESSURE
WILL BE STRETCHED E FROM ERN CO TO SRN ND...AND WITH HIGH PRESSURE
SITTING OVER THE ERN SEABOARD...THAT PUTS US UNDER S/SSW FLOW.
THAT/S RIGHT...WE WILL BE IN THE WARM SECTOR AS THE WARM FRONT
ASSOCIATED WITH THE SYSTEM TO OUR W WILL BE N OF LAKE SUPERIOR BY 00Z
SAT. AND WARM IT WILL BE WITH 850MB TEMPS AROUND 17C.
FRI NIGHT AND SAT...SOLID S/SW FLOW IN THE WARM LOW LEVELS WILL KEEP
TEMPS FROM FALLING TOO FAR FRI NIGHT...ESPECIALLY IN DOWNSLOPING
AREAS. HAVE LOW TEMPS AROUND 60 IN THE DOWNSLOPE AREAS...AND IN THE
UPPER 40S TO 50S ELSEWHERE. WITH HIGHER DEW PTS AND WAA...COULD SEE
FOG OVER MAINLY NRN LAKE SUPERIOR AND EVENTUALLY NRN LAKE MI /WHICH
WOULD LAST UNTIL FROPA SUNDAY/...WHICH I ADDED TO THE FORECAST FOR
FRI NIGHT THROUGH SUN. 850MB TEMPS STAY AROUND 17C THROUGH
SAT...WITH GOOD S/SW FLOW CONTINUING...ALLOWING MIXING TO AROUND
800MB. THIS YIELDS HIGH TEMPS IN THE 80S OVER THE W HALF AND NEAR
LAKE SUPERIOR OVER THE E HALF...WITH HIGHS IN THE 60S CLOSE TO NRN
LAKE MI DUE TO S/SSW FLOW OF THE RELATIVELY COLD LAKE. ATMOSPHERE
LOOKS TOO DRY AND TOO CAPPED FOR CONVECTION TO FORM ON SAT...WHICH
IS GOOD SINCE WE SHOULD HAVE 1500-2000J/KG OF CAPE SAT AFTERNOON.
LOWERED DEW PTS A FEW DEGREES AS MIXING WILL ALLOW DRY AIR TO GET TO
THE SFC. THIS LEADS TO MIN RH VALUES DOWN OF 25 TO 35 PERCENT OVER
THE W HALF OF UPPER MI...AND GREATER THAN 35 PERCENT RH OVER THE E
HALF. THIS BECOMES MORE PROBLEMATIC WHEN CONSIDERING WINDS WILL BE
SLY AT 15-20MPH WITH GUSTS OF 25-35MPH. LOOKS LIKE IT MAY BE A
CRITICAL FIRE WEATHER DAY...BUT THAT WILL NEED TO BE LOOKED AT MORE
CLOSELY BY LATER SHIFTS FOR POSSIBLE FIRE WEATHER HEADLINES.
SAT NIGHT THROUGH MON...BY 00Z SUN...THE UPPER TROUGH WILL HAVE MOVED
FARTHER E...WITH A SHORTWAVE TROUGH OVER MANITOBA...AND POSSIBLY
ANOTHER OVER KS/NE. THE SFC LOW WILL HAVE WEAKENED TO 1002MB AS IT
MOVED TO N OF THE MN ARROWHEAD. THIS PUTS THE COLD JUST W OF LAKE
SUPERIOR AT 00Z SUN. SAT NIGHT WILL BE ANOTHER WARM ONE WITH
CONTINUED STRONG LOW LEVEL FLOW AND WARM LOW LEVEL TEMPS. OVERNIGHT
LOWS LOOK TO BE IN THE 50S AND LOW 60S. DIFFERING MODEL SOLUTIONS
BEGIN TO LOWER CONFIDENCE ON EXACT TIMING OF THE COLD FRONT/PRECIP
DUE MAINLY WITH HOW TO HANDLE A SHORTWAVE MOVING AROUND THE MAIN
UPPER TROUGH SAT NIGHT INTO SUN. THE GFS CONTINUES TO BE THE MOST
AGGRESSIVE WITH THE SHORTWAVE...SHOWING IT STRONGER THAN PRETTY MUCH
ANY OTHER MODEL. THIS MEANS THE GFS ALSO BRINGS THE COLD FRONT
THROUGH FASTER THAN OTHER MODELS. FOR THIS REASON...WILL NOT PUT AS
MUCH OF THE GFS INTO THIS FORECAST. WITH THE IDEA THAT THE GFS IS
ABOUT 6 HOURS TOO FAST WITH FROPA...THE FRONT SHOULD MOVE OVER WRN
UPPER MI SUN AFTERNOON...AND MOVE TO ERN UPPER MI BY 12Z MON...NOTE
THE SLOW EASTWARD PROGRESSION OF THE FRONT. SBCAPES OF AROUND
1000-1500J/KG WILL BE POSSIBLE SUN AFTERNOON AHEAD OF THE
FRONT...BUT CONFIDENCE IN THIS IS A BIT LOW RIGHT NOW DUE TO MODEL
TIMING DIFFERENCES AND UNCERTAINTY IN HOW MUCH CLEARING WILL OCCUR
AHEAD OF THE FRONT. 0-6KM BULK SHEAR LOOKS TO BE AROUND
30KTS...SUFFICIENT FOR ORGANIZED CONVECTION. SO...IT LOOKS LIKE SOME
STRONG TO SEVERE STORMS WILL BE A POSSIBILITY SUN
AFTERNOON/EVENING...BUT CONFIDENCE IS STILL LIMITED. THE COLD FRONT
LOOKS TO COMPLETELY CLEAR THE CWA AROUND 18Z MON...AS THE UPPER
TROUGH AND A SFC RIDGE MOVE INTO THE WRN CWA. 850MB TEMPS OF AROUND
7C MON AFTERNOON WILL MAKE FOR COOLER TEMPS IN THE 60S...EXCEPT IN
THE 50S NEAR LAKE SUPERIOR IN THE NLY WINDS.
MON NIGHT THROUGH WED...EXPECT A GRADUAL WARMING TREND AS AN UPPER
RIDGE MOVES OVERHEAD AND SFC RIDGING SLOWLY MOVES TO E OF THE CWA BY
WED AFTERNOON.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 729 AM EDT THU MAY 17 2012
VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES THROUGH THE PERIOD.
MAIN ITEM OF CONCERN IS POTENTIAL SHOWERS APPROACHING KIWD TODAY.
MUCH OF IT DEPENDS ON HOW AND WHERE SHOWERS OVER SOUTHERN MN WILL
RIDE NE TOWARD WITH THE INCREASING SRLY FLOW TODAY. LIMITED
CONFIDENCE ON THIS OCCURRING...SO WILL LEAVE OUT OF THE FORECAST
GIVEN DRY LOW LEVELS. LLWS STILL EXPECTED AT ALL OF THE TAF SITES
FOR THIS EVENING AND TONIGHT WITH THE STRONG LLVL JET MOVING OVER
UPPER MI. MORE SHOWERS MAY APPROACH CMX TONIGHT...BUT AGAIN KEPT
THOSE OUT OF THE FORECAST GIVEN DRY LOW LEVELS AND LIMITED
CONFIDENCE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 512 AM EDT THU MAY 17 2012
WINDS ACROSS LAKE SUPERIOR SHOULD REMAIN BELOW 30KTS THROUGH THE
PERIOD. HIGH PRESSURE ACROSS THE UPPER GREAT LAKES WILL SHIFT TO THE
LOWER GREAT LAKES THIS AFTERNOON...BEFORE PUSHING OFF THE MID
ATLANTIC SHORELINE ON FRIDAY INTO SATURDAY. LOW PRESSURE OVER
SOUTHERN SASKATCHEWAN AND THE WESTERN DAKOTAS WILL PUSH ACROSS THE
NORTHERN AND CENTRAL PLAINS TONIGHT THROUGH SATURDAY...BEFORE
SLIDING NORTH INTO ONTARIO SATURDAY. THIS WILL ALLOW A COLD FRONT TO
PUSH ACROSS THE UPPER GREAT LAKES SUNDAY INTO EARLY MONDAY. BEHIND
THE FRONT...HIGH PRESSURE WILL BUILD IN FROM THE CENTRAL AND
NORTHERN PLAINS THROUGH TUESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FROST ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MIZ006-007-013-
014-085.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...TITUS
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
516 AM EDT THU MAY 17 2012
.SYNOPSIS...
ISSUED AT 512 AM EDT THU MAY 17 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM
THE PLAINS INTO CNTRL CANADA AND A DOWNSTREAM TROUGH FROM QUEBEC
INTO THE NE CONUS RESULTING IN NW FLOW THROUGH THE NRN GREAT LAKES.
AT THE SFC...HIGH PRES WAS CENTERED OVER LOWER MI WHILE LOW PRES WAS
DEVELOPING OVER THE PLAINS FROM SRN SASK INTO WRN SOUTH DAKOTA. MID
LEVEL WARM ADVECTION AHEAD OF A WARM FRONT OVER THE CNTRL PLAINS
SUPPORTED DEVELOPING SHRA AND A FEW TSRA OVER SW MN.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 512 AM EDT THU MAY 17 2012
TODAY...EXPECT THE BAND OF STRONGER 310K ISENTROPIC LIFT AND
POSITION OF THE 750-650 MB WARM FRONT TO EXPAND TO THE ENE
TODAY...PER NAM/GFS. HOWEVER...SINCE THE PCPN IS MOVING AWAY FROM
THE GREATER LOW LEVEL MOISTURE INTO THE DRY LOW LEVEL AIRMASS TO THE
EAST...PER 00Z MPX/INL/GRB SOUNDINGS...THE PCPN SHOULD REMAIN LIGHT
AND MAINLY TO THE WEST AND SOUTH OF THE CWA. LOCATIONS FROM IWD-IMT
WILL SEE THE BEST CHANCE OF ANY PCPN BUT ONLY SLIGHT CHANCE POPS
WERE INCLUDED WITH ANY PCPN AMOUNTS LESS THAN A TENTH OF AN INCH.
OTHERWISE...WAA WILL HELP PUSH TEMPS INTO THE MID 50S TO LOWER 70S
DESPITE AN INCREASE IN MID HIGH CLOUDS.
TONIGHT...THE FOCUS OF THE LLJ AND STRONGEST MOISTURE TRANSPORT IS
EXPECTED OVER NE MN AND NW WI INTO WRN LAKE SUPERIOR. AREAS OF
SHRA/TSRA SHOULD DEVELOP AND EVENTUALLY SPREAD TO THE EAST AFFECTING
MAINLY THE NW HALF OF THE CWA AS THE LLJ VEERS OVERNIGHT.
HOWEVER...THERE IS STILL SIGNIFICANT UNCERTAINTY WITH THE
TIMING/POSITION OF THE CONVECTION.
FRIDAY...ANY LEFTOVER SHRA/TSRA OVER MAINLY NORTH UPPER MI INTO LAKE
SUPERIOR SHOULD SLIDE TO THE ENE AND DIMINISH DURING THE MORNING AS
THE LLJ WEAKENS. THE COMBINATION OF BUILDING MID-LVL RDG HEIGHTS AND
850 MB WARM FRONT LIFTING WELL NORTH OF THE AREA SHOULD KEEP THE CWA
DRY FRI AFTERNOON. RESIDUAL CLOUDS FROM CONVECTION SHOULD DISSIPATE
FRI AFTERNOON ALLOWING FOR INCREASED SUNSHINE. MIXING OF 850 MB
TEMPS OF AROUND 16C TO THE SFC SHOULD ALLOW FOR HIGH TEMPS FRIDAY TO
REACH INTO THE LOWER 80S OVER WRN INTERIOR LOCATION. COOLER SRLY
FLOW OFF LAKE MI WILL KEEP INLAND HIGHS OVER ERN COUNTIES IN THE LOW
TO MID 70S.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 512 AM EDT THU MAY 17 2012
PERIOD STARTS 00Z SAT WITH A 500MB RIDGE OVER THE CWA...AND A 500MB
TROUGH OVER THE INTERMOUNTAIN WEST. AT THE SFC...994MB LOW PRESSURE
WILL BE STRETCHED E FROM ERN CO TO SRN ND...AND WITH HIGH PRESSURE
SITTING OVER THE ERN SEABOARD...THAT PUTS US UNDER S/SSW FLOW.
THAT/S RIGHT...WE WILL BE IN THE WARM SECTOR AS THE WARM FRONT
ASSOCIATED WITH THE SYSTEM TO OUR W WILL BE N OF LAKE SUPERIOR BY 00Z
SAT. AND WARM IT WILL BE WITH 850MB TEMPS AROUND 17C.
FRI NIGHT AND SAT...SOLID S/SW FLOW IN THE WARM LOW LEVELS WILL KEEP
TEMPS FROM FALLING TOO FAR FRI NIGHT...ESPECIALLY IN DOWNSLOPING
AREAS. HAVE LOW TEMPS AROUND 60 IN THE DOWNSLOPE AREAS...AND IN THE
UPPER 40S TO 50S ELSEWHERE. WITH HIGHER DEW PTS AND WAA...COULD SEE
FOG OVER MAINLY NRN LAKE SUPERIOR AND EVENTUALLY NRN LAKE MI /WHICH
WOULD LAST UNTIL FROPA SUNDAY/...WHICH I ADDED TO THE FORECAST FOR
FRI NIGHT THROUGH SUN. 850MB TEMPS STAY AROUND 17C THROUGH
SAT...WITH GOOD S/SW FLOW CONTINUING...ALLOWING MIXING TO AROUND
800MB. THIS YIELDS HIGH TEMPS IN THE 80S OVER THE W HALF AND NEAR
LAKE SUPERIOR OVER THE E HALF...WITH HIGHS IN THE 60S CLOSE TO NRN
LAKE MI DUE TO S/SSW FLOW OF THE RELATIVELY COLD LAKE. ATMOSPHERE
LOOKS TOO DRY AND TOO CAPPED FOR CONVECTION TO FORM ON SAT...WHICH
IS GOOD SINCE WE SHOULD HAVE 1500-2000J/KG OF CAPE SAT AFTERNOON.
LOWERED DEW PTS A FEW DEGREES AS MIXING WILL ALLOW DRY AIR TO GET TO
THE SFC. THIS LEADS TO MIN RH VALUES DOWN OF 25 TO 35 PERCENT OVER
THE W HALF OF UPPER MI...AND GREATER THAN 35 PERCENT RH OVER THE E
HALF. THIS BECOMES MORE PROBLEMATIC WHEN CONSIDERING WINDS WILL BE
SLY AT 15-20MPH WITH GUSTS OF 25-35MPH. LOOKS LIKE IT MAY BE A
CRITICAL FIRE WEATHER DAY...BUT THAT WILL NEED TO BE LOOKED AT MORE
CLOSELY BY LATER SHIFTS FOR POSSIBLE FIRE WEATHER HEADLINES.
SAT NIGHT THROUGH MON...BY 00Z SUN...THE UPPER TROUGH WILL HAVE MOVED
FARTHER E...WITH A SHORTWAVE TROUGH OVER MANITOBA...AND POSSIBLY
ANOTHER OVER KS/NE. THE SFC LOW WILL HAVE WEAKENED TO 1002MB AS IT
MOVED TO N OF THE MN ARROWHEAD. THIS PUTS THE COLD JUST W OF LAKE
SUPERIOR AT 00Z SUN. SAT NIGHT WILL BE ANOTHER WARM ONE WITH
CONTINUED STRONG LOW LEVEL FLOW AND WARM LOW LEVEL TEMPS. OVERNIGHT
LOWS LOOK TO BE IN THE 50S AND LOW 60S. DIFFERING MODEL SOLUTIONS
BEGIN TO LOWER CONFIDENCE ON EXACT TIMING OF THE COLD FRONT/PRECIP
DUE MAINLY WITH HOW TO HANDLE A SHORTWAVE MOVING AROUND THE MAIN
UPPER TROUGH SAT NIGHT INTO SUN. THE GFS CONTINUES TO BE THE MOST
AGGRESSIVE WITH THE SHORTWAVE...SHOWING IT STRONGER THAN PRETTY MUCH
ANY OTHER MODEL. THIS MEANS THE GFS ALSO BRINGS THE COLD FRONT
THROUGH FASTER THAN OTHER MODELS. FOR THIS REASON...WILL NOT PUT AS
MUCH OF THE GFS INTO THIS FORECAST. WITH THE IDEA THAT THE GFS IS
ABOUT 6 HOURS TOO FAST WITH FROPA...THE FRONT SHOULD MOVE OVER WRN
UPPER MI SUN AFTERNOON...AND MOVE TO ERN UPPER MI BY 12Z MON...NOTE
THE SLOW EASTWARD PROGRESSION OF THE FRONT. SBCAPES OF AROUND
1000-1500J/KG WILL BE POSSIBLE SUN AFTERNOON AHEAD OF THE
FRONT...BUT CONFIDENCE IN THIS IS A BIT LOW RIGHT NOW DUE TO MODEL
TIMING DIFFERENCES AND UNCERTAINTY IN HOW MUCH CLEARING WILL OCCUR
AHEAD OF THE FRONT. 0-6KM BULK SHEAR LOOKS TO BE AROUND
30KTS...SUFFICIENT FOR ORGANIZED CONVECTION. SO...IT LOOKS LIKE SOME
STRONG TO SEVERE STORMS WILL BE A POSSIBILITY SUN
AFTERNOON/EVENING...BUT CONFIDENCE IS STILL LIMITED. THE COLD FRONT
LOOKS TO COMPLETELY CLEAR THE CWA AROUND 18Z MON...AS THE UPPER
TROUGH AND A SFC RIDGE MOVE INTO THE WRN CWA. 850MB TEMPS OF AROUND
7C MON AFTERNOON WILL MAKE FOR COOLER TEMPS IN THE 60S...EXCEPT IN
THE 50S NEAR LAKE SUPERIOR IN THE NLY WINDS.
MON NIGHT THROUGH WED...EXPECT A GRADUAL WARMING TREND AS AN UPPER
RIDGE MOVES OVERHEAD AND SFC RIDGING SLOWLY MOVES TO E OF THE CWA BY
WED AFTERNOON.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 130 AM EDT THU MAY 17 2012
VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES THROUGH THE PERIOD.
MAIN ITEM OF CONCERN IS POTENTIAL SHOWERS APPROACHING KIWD
TOMORROW. MUCH OF IT DEPENDS ON SHOWERS DEVELOPMENT IN THE ERN
DAKOTAS TONIGHT...WHICH WILL RIDE NE WITH THE INCREASING SRLY FLOW
THROUGH THE DAY THURSDAY. LIMITED CONFIDENCE ON THIS OCCURRING...SO
WILL LEAVE OUT OF THE FORECAST. ADDED IN LLWS TO ALL OF THE TAF
SITES FOR TOMORROW EVENING WITH THE STRONG LLVL JET MOVING OVER
UPPER MI.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 512 AM EDT THU MAY 17 2012
WINDS ACROSS LAKE SUPERIOR SHOULD REMAIN BELOW 30KTS THROUGH THE
PERIOD. HIGH PRESSURE ACROSS THE UPPER GREAT LAKES WILL SHIFT TO THE
LOWER GREAT LAKES THIS AFTERNOON...BEFORE PUSHING OFF THE MID
ATLANTIC SHORELINE ON FRIDAY INTO SATURDAY. LOW PRESSURE OVER
SOUTHERN SASKATCHEWAN AND THE WESTERN DAKOTAS WILL PUSH ACROSS THE
NORTHERN AND CENTRAL PLAINS TONIGHT THROUGH SATURDAY...BEFORE
SLIDING NORTH INTO ONTARIO SATURDAY. THIS WILL ALLOW A COLD FRONT TO
PUSH ACROSS THE UPPER GREAT LAKES SUNDAY INTO EARLY MONDAY. BEHIND
THE FRONT...HIGH PRESSURE WILL BUILD IN FROM THE CENTRAL AND
NORTHERN PLAINS THROUGH TUESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FROST ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MIZ006-007-013-
014-085.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...KC
MARINE...TITUS
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
920 PM MDT FRI MAY 18 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY...
A SURFACE HIGH BUILDING IN FROM THE NORTHWEST IS CLEARING SKIES
FROM THAT DIRECTION. THEREFORE TRIMMED POPS IN THE WEST TO REFLECT
THE LATEST RADAR TRENDS WHICH CORRESPOND TO GUIDANCE. ALSO MADE A
FEW TWEAKS ON WINDS. THE REST OF THE FORECAST CONTINUES ON-TRACK.
SCT
PREVIOUS UPDATE...
DID AN AN EARLY...PARTIAL UPDATE BASED ON RADAR TRENDS...MAINLY
IN THE EASTERN ZONES...TO INCREASE POPS AND CHANGE WX TO AREAL
COVERAGE FOR THIS EVENING. MOST RAIN SHOULD MOVE INTO NORTH DAKOTA
AFTER MIDNIGHT BUT LEFT SMALL CHANCE POPS IN THE EAST. SCT
PREVIOUS DISCUSSION...
WATER VAPOR IMAGERY AND 500 MB HEIGHT FIELD SHOWS A FAIRLY ACTIVE
AND PROGRESSIVE WEATHER PATTERN ACROSS THE CONUS. AREAS OF WEAK
LOW PRESSURE ARE SETTING OFF SOME THUNDERSTORMS OVER THE
SOUTHEASTERN STATES AND THE INTER-MOUNTAIN WESTERN STATES. WEAK
HIGH PRESSURE HAS TAKEN CONTROL OVER THE MID MISSISSIPPI AND OHIO
RIVER VALLEYS AND THE WEST COAST.
THE ROCKY MOUNTAIN STORM SYSTEM WHICH BROUGHT MORE THAN A WETTING
RAIN TO GLASGOW EARLY THIS MORNING CONTINUES TO MOVE SCATTERED
RAIN SHOWERS THROUGH NORTHEAST MONTANA THIS AFTERNOON. SOME
CLEARING FROM THE WEST HAS BEGUN TO EAT AWAY THE RAIN SHOWERS
WHILE MORE ORGANIZED CONVECTION CONTINUES TO SUPPORT RAIN SHOWERS
OF A MORE WIDESPREAD NATURE OVER OUR SOUTHEASTERN ZONES. HRRR AND
NAM MODELS PICKED UP ON THIS SOUTHEASTERN PRECIP VERY WELL WHILE
THE GFS IGNORED IT COMPLETELY. WOULD TEND TO LEAN A BIT AWAY FROM
THE GFS FOR POPS AND QPF IN THE NEAR SHORT TERM WHILE THIS STORM
SYSTEM MOVES AWAY TO WARD THE EAST TONIGHT. IN FACT...DURING THE
LATE TONIGHT AND OVERNIGHT HOURS THERE SEEMS TO BE VERY GOOD MODEL
AGREEMENT SHOWING THE EXITING SYSTEM BRINGING A SIGNIFICANT AMOUNT
OF RAIN TO THE FAR SOUTHEASTERN CORNER OF OUR CWA. I MAY HAVE BEEN
A LITTLE TOO CONSERVATIVE WITH QPF AND THAT MAY NEED TO BE
INCREASED WITH AN UPDATE TONIGHT.
BY SATURDAY MORNING...PRECIPITATION WILL HAVE MOVED COMPLETELY
AWAY TO THE EAST OF OUR CWA AS THE UPPER LEVEL FLOW BECOMES MORE
ZONAL AND VERY WEAK RIDGING TAKES OVER ACROSS THE REGION
THROUGHOUT THE REMAINDER OF THE WEEKEND WITH MOSTLY CLEAR SKIES.
THIS WILL ALLOW TEMPERATURES TO QUICKLY REBOUND TO NORMAL AND
ABOVE NORMAL LEVELS FOR THIS TIME OF YEAR. WIDESPREAD CLOUDINESS
WILL AGAIN APPROACH FROM THE WEST BY LATE SUNDAY IN TIME TO HELP
FILTER OUT THE ANNULAR SOLAR ECLIPSE NEAR SUNSET. BMICKELSON
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
NOT TOO MANY CHANGES WERE MADE TO GOING FORECAST AS PERIOD LOOKS
RATHER UNSETTLED. DID INCREASE THEM SLIGHTLY FOR TUESDAY AS MOISTURE
AND INSTABILITY POOL TO OUR SOUTHEAST AND MOVE IN ON RETURN
SOUTH-SOUTHEAST FLOW.
THE GFS CONTINUES TO KEEP THE AREA RATHER UNSETTLED AS A DEEP UPPER
TROUGH SETS UP OVER THE WESTERN UNITED STATES. WILL KEEP MOSTLY
CHANCE POPS GOING. JAMBA
PREVIOUS DISCUSSION...
THE EXTENDED PERIOD BEGINS SUNDAY NIGHT WITH ZONAL FLOW ALOFT
THAT WILL BECOME A NARROW WAVE UPPER RIDGE ON MONDAY. THIS RIDGING
WILL INCREASE THICKNESS HEIGHTS AND BEGIN A WARM-UP
MONDAY...POSSIBLY LASTING THROUGH TUESDAY.
MONDAY AFTERNOON AND EVENING A WEAK COLD FRONT FROM AN UPPER
TROUGH DIGGING INTO THE PAC-NW WILL MOVE INTO MONTANA. THIS FRONT
WILL INCREASE INSTABILITY...MAINLY OVER CENTRAL MONTANA. HOWEVER
SOME THUNDERSTORMS COULD DRIFT INTO NORTHEAST MONTANA. THEN ON
TUESDAY THE TROUGH SWINGS ACROSS THE NORTHERN ROCKIES SENDING
ANOTHER STRONGER COLD FRONT INTO THE NORTHERN HIGH PLAINS. THERE
ARE INDICATIONS OF EVEN GREATER INSTABILITY ON TUESDAY AND TUESDAY
EVENING...FOR THE POSSIBILITY OF SEVERAL SEVERE THUNDERSTORMS THAT
COULD MOVE INTO WESTERN NORTH DAKOTA FROM NE MONTANA.
THE GFS AND EC DISAGREE ON HOW THE TROUGH DEVELOPS. BUT BOTH SEEM
TO AGREE WITH THE TROUGH BECOMING MORE OF A LONG WAVE AND
REMAINING OVER THE REGION THROUGH THE REST OF THE EXTENDED
PERIOD...TRENDING TEMPERATURES TO BELOW AVERAGE BY THURSDAY AND
FRIDAY. THE PERIOD WILL ALSO LIKELY SEE CONTINUING PERIODS OF
SHOWER ACTIVITY. THE GFS CLOSES OFF THE LOW AND STACKS UP OVER
WESTERN NORTH DAKOTA WEDNESDAY NIGHT...WHICH TENDS TO RETROGRADE
PRECIPITATION BACK INTO NEMONT. THIS WOULD ALSO DEVELOP STRONG
WINDS. THE EC ON THE OTHER HAND LIFTS THE CLOSED UPPER LOW INTO
SOUTHERN ALBERTA AND SASKATCHEWAN. THEREFORE MODEL UNCERTAINTY
WILL MAKE POPS AND QPF AMOUNTS DIFFICULT TO FORECAST. HOWEVER THE
REST OF THE EXTENDED PERIOD SHOULD HAVE SHOWERS OR RAIN WITH THE
COOLER TEMPERATURES. SCT
&&
.AVIATION...
SHOWERS CONTINUE EAST OF GLASGOW THIS EVENING AND SHOULD CONTINUE
INTO THE OVERNIGHT HOURS. VFR CONDITIONS ARE EXPECTED THROUGH
MIDNIGHT AND THEN POCKETS OF MVFR WILL DEVELOP FROM 09Z-15Z ACROSS
THE EAST BEFORE CLEARING SKIES FOR SATURDAY. PROTON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
703 PM MDT FRI MAY 18 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY...
DID AN AN EARLY...PARTIAL UPDATE BASED ON RADAR TRENDS...MAINLY IN THE
EASTERN ZONES...TO INCREASE POPS AND CHANGE WX TO AREAL COVERAGE FOR
THIS EVENING. MOST RAIN SHOULD MOVE INTO NORTH DAKOTA AFTER
MIDNIGHT BUT LEFT SMALL CHANCE POPS IN THE EAST. SCT
PREVIOUS DISCUSSION...
WATER VAPOR IMAGERY AND 500 MB HEIGHT FIELD SHOWS A FAIRLY ACTIVE
AND PROGRESSIVE WEATHER PATTERN ACROSS THE CONUS. AREAS OF WEAK
LOW PRESSURE ARE SETTING OFF SOME THUNDERSTORMS OVER THE
SOUTHEASTERN STATES AND THE INTER-MOUNTAIN WESTERN STATES. WEAK
HIGH PRESSURE HAS TAKEN CONTROL OVER THE MID MISSISSIPPI AND OHIO
RIVER VALLEYS AND THE WEST COAST.
THE ROCKY MOUNTAIN STORM SYSTEM WHICH BROUGHT MORE THAN A WETTING
RAIN TO GLASGOW EARLY THIS MORNING CONTINUES TO MOVE SCATTERED
RAIN SHOWERS THROUGH NORTHEAST MONTANA THIS AFTERNOON. SOME
CLEARING FROM THE WEST HAS BEGUN TO EAT AWAY THE RAIN SHOWERS
WHILE MORE ORGANIZED CONVECTION CONTINUES TO SUPPORT RAIN SHOWERS
OF A MORE WIDESPREAD NATURE OVER OUR SOUTHEASTERN ZONES. HRRR AND
NAM MODELS PICKED UP ON THIS SOUTHEASTERN PRECIP VERY WELL WHILE
THE GFS IGNORED IT COMPLETELY. WOULD TEND TO LEAN A BIT AWAY FROM
THE GFS FOR POPS AND QPF IN THE NEAR SHORT TERM WHILE THIS STORM
SYSTEM MOVES AWAY TO WARD THE EAST TONIGHT. IN FACT...DURING THE
LATE TONIGHT AND OVERNIGHT HOURS THERE SEEMS TO BE VERY GOOD MODEL
AGREEMENT SHOWING THE EXITING SYSTEM BRINGING A SIGNIFICANT AMOUNT
OF RAIN TO THE FAR SOUTHEASTERN CORNER OF OUR CWA. I MAY HAVE BEEN
A LITTLE TOO CONSERVATIVE WITH QPF AND THAT MAY NEED TO BE
INCREASED WITH AN UPDATE TONIGHT.
BY SATURDAY MORNING...PRECIPITATION WILL HAVE MOVED COMPLETELY
AWAY TO THE EAST OF OUR CWA AS THE UPPER LEVEL FLOW BECOMES MORE
ZONAL AND VERY WEAK RIDGING TAKES OVER ACROSS THE REGION
THROUGHOUT THE REMAINDER OF THE WEEKEND WITH MOSTLY CLEAR SKIES.
THIS WILL ALLOW TEMPERATURES TO QUICKLY REBOUND TO NORMAL AND
ABOVE NORMAL LEVELS FOR THIS TIME OF YEAR. WIDESPREAD CLOUDINESS
WILL AGAIN APPROACH FROM THE WEST BY LATE SUNDAY IN TIME TO HELP
FILTER OUT THE ANNULAR SOLAR ECLIPSE NEAR SUNSET. BMICKELSON
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
NOT TOO MANY CHANGES WERE MADE TO GOING FORECAST AS PERIOD LOOKS
RATHER UNSETTLED. DID INCREASE THEM SLIGHTLY FOR TUESDAY AS MOISTURE
AND INSTABILITY POOL TO OUR SOUTHEAST AND MOVE IN ON RETURN
SOUTH-SOUTHEAST FLOW.
THE GFS CONTINUES TO KEEP THE AREA RATHER UNSETTLED AS A DEEP UPPER
TROUGH SETS UP OVER THE WESTERN UNITED STATES. WILL KEEP MOSTLY
CHANCE POPS GOING. JAMBA
PREVIOUS DISCUSSION...
THE EXTENDED PERIOD BEGINS SUNDAY NIGHT WITH ZONAL FLOW ALOFT
THAT WILL BECOME A NARROW WAVE UPPER RIDGE ON MONDAY. THIS RIDGING
WILL INCREASE THICKNESS HEIGHTS AND BEGIN A WARM-UP
MONDAY...POSSIBLY LASTING THROUGH TUESDAY.
MONDAY AFTERNOON AND EVENING A WEAK COLD FRONT FROM AN UPPER
TROUGH DIGGING INTO THE PAC-NW WILL MOVE INTO MONTANA. THIS FRONT
WILL INCREASE INSTABILITY...MAINLY OVER CENTRAL MONTANA. HOWEVER
SOME THUNDERSTORMS COULD DRIFT INTO NORTHEAST MONTANA. THEN ON
TUESDAY THE TROUGH SWINGS ACROSS THE NORTHERN ROCKIES SENDING
ANOTHER STRONGER COLD FRONT INTO THE NORTHERN HIGH PLAINS. THERE
ARE INDICATIONS OF EVEN GREATER INSTABILITY ON TUESDAY AND TUESDAY
EVENING...FOR THE POSSIBILITY OF SEVERAL SEVERE THUNDERSTORMS THAT
COULD MOVE INTO WESTERN NORTH DAKOTA FROM NE MONTANA.
THE GFS AND EC DISAGREE ON HOW THE TROUGH DEVELOPS. BUT BOTH SEEM
TO AGREE WITH THE TROUGH BECOMING MORE OF A LONG WAVE AND
REMAINING OVER THE REGION THROUGH THE REST OF THE EXTENDED
PERIOD...TRENDING TEMPERATURES TO BELOW AVERAGE BY THURSDAY AND
FRIDAY. THE PERIOD WILL ALSO LIKELY SEE CONTINUING PERIODS OF
SHOWER ACTIVITY. THE GFS CLOSES OFF THE LOW AND STACKS UP OVER
WESTERN NORTH DAKOTA WEDNESDAY NIGHT...WHICH TENDS TO RETROGRADE
PRECIPITATION BACK INTO NEMONT. THIS WOULD ALSO DEVELOP STRONG
WINDS. THE EC ON THE OTHER HAND LIFTS THE CLOSED UPPER LOW INTO
SOUTHERN ALBERTA AND SASKATCHEWAN. THEREFORE MODEL UNCERTAINTY
WILL MAKE POPS AND QPF AMOUNTS DIFFICULT TO FORECAST. HOWEVER THE
REST OF THE EXTENDED PERIOD SHOULD HAVE SHOWERS OR RAIN WITH THE
COOLER TEMPERATURES. SCT
&&
.AVIATION...
SHOWERS CONTINUE EAST OF GLASGOW THIS EVENING AND SHOULD CONTINUE
INTO THE OVERNIGHT HOURS. VFR CONDITIONS ARE EXPECTED THROUGH
MIDNIGHT AND THEN POCKETS OF MVFR WILL DEVELOP FROM 09Z-15Z ACROSS
THE EAST BEFORE CLEARING SKIES FOR SATURDAY. PROTON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
919 PM CDT FRI MAY 18 2012
.UPDATE...
UPDATED WIND FORECAST. WEATHER FORECAST ON TRACK. THUNDERSTORMS
NOT PUTTING OUT MUCH IN WAY OF RAIN BUT SOME WIND AND MOSTLY SMALL
HAIL. NUMEROUS LIGHTNING STRIKES WITH CLUSTER IN GARDEN GRANT AND
ARTHUR COUNTIES. LOOKS TO BE JUST ENOUGH TREAT TO DIMINISH FIRE
THREAT.
&&
.PREV DISCUSSION... /ISSUED 842 PM CDT FRI MAY 18 2012/
AVIATION...
STRONG STORMS MOVING ACROSS WESTERN NEBRASKA THIS EVENING. HAVE
INCLUDED TEMPO GROUP FOR KVTN THROUGH 4Z. NORTHWEST WINDS BUILDING
INTO THE NORTHWEST PANHANDLE. FROPA EXPECTED AT KVTN AROUND 1906Z
AND KLBF 1911Z. STRATUS AND CEILINGS LOWERING INTO THE IFR CATEGORIES
WITH DRIZZLE EXPECTED TO BUILD IN AFTER FROPA AND THEN LIGHT TO
MODERATE RAIN DEVELOPING THROUGH THE AFTERNOON WITH CEILINGS LIFTING
INTO MVFR.
PREV DISCUSSION... /ISSUED 330 PM CDT FRI MAY 18 2012/
DISCUSSION...
A POWERFUL UPPER LEVEL DISTURBANCE ACROSS COLO WILL MOVE SLOWLY
EAST TONIGHT AND SATURDAY PRODUCING SCATTERED TSTMS...MAINLY
ACROSS NORTH AND WEST PARTS OF THE FCST AREA WHICH WILL BE CLOSER
TO THE BEST DYNAMICS. SUPER ENSEMBLE FCST QPF SUGGESTS AROUND 1/4 INCH
OF RAIN NEAR NORTH PLATE AND CLOSE TO 3/4 OF AN INCH NEAR VALENTINE.
FOR THIS EVENING THE THREAT OF HIGH BASED TSTMS CAPABLE OF GUSTY
OR PERHAPS ISOLATED DAMAGING DOWNBURSTS WILL CONTINUE AS SFC RH IS
OPERATING BELOW 40 PERCENT. ONCE THE COLD FRONT SWEEPS SOUTH
LATER TONIGHT THE WIND THREAT SHOULD DIMINISH. THE ECM CONTINUES
TO BE SLOWER WITH COLD FRONT HOLDING IT UP SOME SATURDAY AFTERNOON
ACROSS THE ERN ZONES. THIS WAS INCORPORATED IN THE TEMP FORECAST
FOR HIGHS IN THE 70S EAST...BUT UPPER 50S TO AROUND 60 WEST.
THE UPPER LEVEL DISTURBANCE SHOULD CLEAR THE FCST AREA SATURDAY
NIGHT WITH STRONG HIGH PRESSURE BUILDING IN SUNDAY FOR NEARLY
CLEAR SKIES AND HIGHS IN THE 60S TO AROUND 70S. THE SFC HIGH WILL
MOVE OFF EAST QUICKLY MONDAY WITH SOUTHERLY RETURN FLOW DEVELOPING
AND A STRONG THERMAL RIDGE DEVELOPING ACROSS THE HIGH PLAINS AND
CNTL ROCKIES BY LATE MONDAY AFTERNOON. THIS THERMAL RIDGE SHOULD
MIGRATE EAST INTO THE NEB PANHANDLE TUESDAY AFTERNOON. MIX DOWN
TOOLS FROM 700 MB SUGGESTS HIGHS IN THE LOWER 90S. FOR NOW 80S
WILL OPERATE. ALL MODELS EXCEPT THE SLOWER AND VERY WARM GEM THEN
SWEEP A COLD FRONT THROUGH WEDNESDAY LOWERING TEMPS ABOUT 10
DEGREES. THE FRONT WILL THEN LIFT SLOWLY NORTH THROUGH KS AND
BECOME STATIONARY ACROSS SWRN NEB FRIDAY. ALL ALONG A DEEP UPPER
LEVEL TROF WILL DROP INTO THE WRN U.S. AND WINDS ALOFT WILL
BECOME SOUTHWEST AND INCREASE IN SPEED. SFC LOW PRESSURE WILL DEEPEN TO
BELOW 990 MB ACROSS WRN KS SUPPORTING WINDY CONDITIONS...SHARP
MOISTURE GRADIENTS AND A STRONG CAP...PERHAPS AS STRONG AS 12C
ACROSS SRN NEB. GIVEN THE FAST FLOW ALOFT AND FOCUS OF THE SFC
LOW...ISOLATED AND LOW-CHC POPS ARE IN PLACE LATE TUESDAY THROUGH
THURSDAY.
FIRE WEATHER...
A FAIRLY SHARP DRYLINE HAS FORMED NEAR WRAY AND HOLYOKE COLO THIS
AFTN WHERE RH IS RUNNING 11 TO 15 PERCENT. THE RUC SHOWS THIS
DRYLINE PUSHING EAST INTO SWRN NEB LATE THIS AFTERNOON AS THE SFC
LOW MOVES EAST TO NEAR BURLINGTON COLO. THE RED FLAG WARNING WILL
CONTINUE IN EFFECT THIS EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...POWER
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
842 PM CDT FRI MAY 18 2012
.AVIATION...
STRONG STORMS MOVING ACROSS WESTERN NEBRASKA THIS EVENING. HAVE
INCLUDED TEMPO GROUP FOR KVTN THROUGH 4Z. NORTHWEST WINDS BUILDING
INTO THE NORTHWEST PANHANDLE. FROPA EXPECTED AT KVTN AROUND 1906Z
AND KLBF 1911Z. STRATUS AND CEILINGS LOWERING INTO THE IFR CATEGORIES
WITH DRIZZLE EXPECTED TO BUILD IN AFTER FROPA AND THEN LIGHT TO
MODERATE RAIN DEVELOPING THROUGH THE AFTERNOON WITH CEILINGS LIFTING
INTO MVFR.
&&
.PREV DISCUSSION... /ISSUED 330 PM CDT FRI MAY 18 2012/
DISCUSSION...
A POWERFUL UPPER LEVEL DISTURBANCE ACROSS COLO WILL MOVE SLOWLY
EAST TONIGHT AND SATURDAY PRODUCING SCATTERED TSTMS...MAINLY
ACROSS NORTH AND WEST PARTS OF THE FCST AREA WHICH WILL BE CLOSER
TO THE BEST DYNAMICS. SUPER ENSEMBLE FCST QPF SUGGESTS AROUND 1/4 INCH
OF RAIN NEAR NORTH PLATE AND CLOSE TO 3/4 OF AN INCH NEAR VALENTINE.
FOR THIS EVENING THE THREAT OF HIGH BASED TSTMS CAPABLE OF GUSTY
OR PERHAPS ISOLATED DAMAGING DOWNBURSTS WILL CONTINUE AS SFC RH IS
OPERATING BELOW 40 PERCENT. ONCE THE COLD FRONT SWEEPS SOUTH
LATER TONIGHT THE WIND THREAT SHOULD DIMINISH. THE ECM CONTINUES
TO BE SLOWER WITH COLD FRONT HOLDING IT UP SOME SATURDAY AFTERNOON
ACROSS THE ERN ZONES. THIS WAS INCORPORATED IN THE TEMP FORECAST
FOR HIGHS IN THE 70S EAST...BUT UPPER 50S TO AROUND 60 WEST.
THE UPPER LEVEL DISTURBANCE SHOULD CLEAR THE FCST AREA SATURDAY
NIGHT WITH STRONG HIGH PRESSURE BUILDING IN SUNDAY FOR NEARLY
CLEAR SKIES AND HIGHS IN THE 60S TO AROUND 70S. THE SFC HIGH WILL
MOVE OFF EAST QUICKLY MONDAY WITH SOUTHERLY RETURN FLOW DEVELOPING
AND A STRONG THERMAL RIDGE DEVELOPING ACROSS THE HIGH PLAINS AND
CNTL ROCKIES BY LATE MONDAY AFTERNOON. THIS THERMAL RIDGE SHOULD
MIGRATE EAST INTO THE NEB PANHANDLE TUESDAY AFTERNOON. MIX DOWN
TOOLS FROM 700 MB SUGGESTS HIGHS IN THE LOWER 90S. FOR NOW 80S
WILL OPERATE. ALL MODELS EXCEPT THE SLOWER AND VERY WARM GEM THEN
SWEEP A COLD FRONT THROUGH WEDNESDAY LOWERING TEMPS ABOUT 10
DEGREES. THE FRONT WILL THEN LIFT SLOWLY NORTH THROUGH KS AND
BECOME STATIONARY ACROSS SWRN NEB FRIDAY. ALL ALONG A DEEP UPPER
LEVEL TROF WILL DROP INTO THE WRN U.S. AND WINDS ALOFT WILL
BECOME SOUTHWEST AND INCREASE IN SPEED. SFC LOW PRESSURE WILL DEEPEN TO
BELOW 990 MB ACROSS WRN KS SUPPORTING WINDY CONDITIONS...SHARP
MOISTURE GRADIENTS AND A STRONG CAP...PERHAPS AS STRONG AS 12C
ACROSS SRN NEB. GIVEN THE FAST FLOW ALOFT AND FOCUS OF THE SFC
LOW...ISOLATED AND LOW-CHC POPS ARE IN PLACE LATE TUESDAY THROUGH
THURSDAY.
AVIATION...
SOUTH TO SOUTHEAST WINDS AT 15 TO 25 KTS...WILL SHIFT TO THE NORTH
AFTER 06Z SATURDAY BEHIND A COLD FRONT. THE FRONT WILL MOVE THROUGH
THE KVTN TAF SITE AROUND 06Z SATURDAY...AND INTO THE KLBF TAF SITE
AREA AROUND 09Z SATURDAY. A FEW T-STORMS WILL BE POSSIBLE BOTH THIS
EVENING AND OVERNIGHT WITH THE FRONTAL PASSAGE...BUT COVERAGE SHOULD
REMAIN LIMITED AND WILL NOT INCLUDE IN THE OFFICIAL FORECAST AT THIS
TIME. CONFIDENCE IS ALSO NOT HIGH ON ANY MVFR CEILINGS DUE TO
STRATUS BEHIND THE FRONT. HAVE ALSO LEFT THIS OUT FOR NOW...AS
CONDITIONS HAVE BEEN VERY DRY LATELY...AND NOT CERTAIN THE BOUNDARY
LAYER WILL MOISTEN ENOUGH FOR STRATUS.
FIRE WEATHER...
A FAIRLY SHARP DRYLINE HAS FORMED NEAR WRAY AND HOLYOKE COLO THIS
AFTN WHERE RH IS RUNNING 11 TO 15 PERCENT. THE RUC SHOWS THIS
DRYLINE PUSHING EAST INTO SWRN NEB LATE THIS AFTERNOON AS THE SFC
LOW MOVES EAST TO NEAR BURLINGTON COLO. THE RED FLAG WARNING WILL
CONTINUE IN EFFECT THIS EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...RED FLAG WARNING UNTIL 9 PM CDT THIS EVENING FOR NEZ210.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...POWER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
256 PM CDT THU MAY 17 2012
.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT...WINDY CONDITIONS HAVE
DEVELOPED ACROSS MUCH OF THE FORECAST AREA TODAY AS DEEP MIXING HAS
BEEN REALIZED ALONG WITH A TIGHTENING PRESSURE GRADIENT IN RESPONSE
TO AN AREA OF SURFACE LOW PRESSURE TO OUR WEST. DO NOT EXPECT THESE
WINDS TO DIMINISH RAPIDLY THROUGH THE LATE AFTERNOON AND EARLY
EVENING HOURS AS PRESSURE GRADIENT WILL BE SLOW TO RELAX AND WINDS
FROM ALOFT WILL NOT DECOUPLE UNTIL AFTER SUNSET...SO WENT AHEAD AN
KEPT WIND ADVISORY GOING UNTIL 02Z THIS EVENING. IN ADDITION TO THE
WINDS...THERE REMAINS A SLIGHT CHANCE FOR A FEW THUNDERSTORMS THIS
EVENING ACROSS THE WESTERN FRINGES OF THE FORECAST AREA...AS FORCING
FROM WELL DEFINED UPPER LEVEL LOW MAY HELP INITIATE A FEW STORMS.
BOTH 12Z HRRR AND WRF HINT AT THIS TYPE OF DEVELOPMENT...BUT
CONFIDENCE NOT HIGH ENOUGH TO INCREASE COVERAGE AS INSTABILITY
REMAINS FAIRLY MARGINAL AND SIGNIFICANT COVERAGE IS NOT EXPECTED. IF
STORMS DO DEVELOP HOWEVER...MAIN THREAT APPEARS TO BE VERY GUSTY
WINDS AND SMALL HAIL.
OVERNIGHT...THE COMBINATION OF A SCT-BKN CIRRUS SHIELD AND CONTINUED
BREEZY SOUTHERLY WINDS SHOULD KEEP TEMPERATURES ELEVATED ABOVE
SEASONAL LEVELS...WITH LOW TEMPERATURES STRUGGLING TO FALL TO NEAR
60 IN MOST LOCATIONS.
WHILE DRY CONDITIONS ARE EXPECTED TO PREVAIL ON FRIDAY...ANOTHER
WINDY DAY APPEARS TO BE IN STORE ACROSS THE REGION AS THE PRESSURE
GRADIENT REMAINS TIGHT ACROSS THE REGION AND ONCE AGAIN GOOD MIXING
IS ANTICIPATED. WHILE A WIND ADVISORY MAY EVENTUALLY BECOME
NECESSARY ACROSS THE EASTERN HALF OF THE FORECAST AREA DURING THE
AFTERNOON HOURS...DECIDED TO HOLD OFF AT THIS POINT AS WE PRESENTLY
ALREADY HAVE AN ADVISORY HIGHLIGHTED FOR TODAY. DID HOWEVER INCLUDE
ADVISORY LEVEL WINDS FOR MUCH OF THE EASTERN HALF OF THE AREA DURING
THE AFTERNOON HOURS TOMORROW IN LATEST GRIDS. IN ADDITION TO
WINDS...EXPECT ANOTHER VERY WARM AFTERNOON FOR MID MAY...AND
INCREASED AFTERNOON TEMPS SEVERAL DEGREES IN RESPONSE TO WARMING 850
MB TEMPS AND A WARM START TO THE DAY ANTICIPATED.
.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY. THE PRIMARY WEATHER
FEATURES ARE A COLD FRONT THAT WILL TRACK ACROSS THE CWA ON SATURDAY
AND THEN A WESTERN CONUS UPPER TROUGH THAT DEVELOPS BY THE MIDDLE
OF NEXT WEEK.
FRIDAY NIGHT...MOST FORECAST MODELS ARE DRY FOR OUR FORECAST AREA
WITH THE BETTER CHANCE OF SHOWERS AND THUNDERSTORMS LOCATED ACROSS
PORTIONS OF WESTERN AND NORTHERN NEBRASKA. WILL CONTINUE WITH A
SLIGHT CHANCE OF THUNDERSTORMS ACROSS OUR NORTHWEST
ZONES...PRIMARILY NORTHWEST OF A HOLDREGE TO GRAND ISLAND LINE.
SATURDAY...THIS WILL BE OUR BEST CHANCE OF SEEING SHOWERS AND
THUNDERSTORMS WITHIN THE NEXT 5 DAYS...OR AT LEAST THROUGH TUESDAY.
AN UPPER LEVEL SHORT WAVE WILL SLIDE ACROSS THE CENTRAL PLAINS
ACCOMPANIED BY A FAIRLY STRONG SFC COLD FRONT. THE MORNING SHOULD BE
DRY...BUT SHOWERS AND THUNDERSTORMS WILL FORM ALONG AND BEHIND THE
COLD FRONT BY MID TO LATE AFTERNOON. THE COLD FRONT WILL PRIMARILY
TRACK ACROSS OUR CWA DURING THE AFTERNOON HOURS...BUT MAY NOT EXIT
OUR FAR SOUTHEASTERN ZONES UNTIL AROUND OR A BIT AFTER SUNSET. THERE
MAY BE TWO AREAS OF PRECIPITATION ASSOCIATED WITH THIS SYSTEM. THE
FIRST WILL BE AN AREA OF STRATIFORM RAIN SHOWERS WITH GENERAL NON
SEVERE THUNDERSTORMS WELL BEHIND THE FRONT. THE SECOND AREA WILL BE
STRONG TO SEVERE THUNDERSTORMS THAT SHOULD FORM RIGHT ALONG OR VERY
NEAR THE COLD FRONT. INSTABILITY WILL BE RATHER HIGH ALONG THE FRONT
BY LATE AFTERNOON...ALTHOUGH THE WIND SHEAR WILL BE MORE MARGINAL
AND UNIDIRECTIONAL. BULK SHEAR VECTORS ARE ORIENTED RATHER PARALLEL
TO THE SFC COLD FRONT AND THERE SHOULD BE PRETTY GOOD FORCING RIGHT
ALONG THE FRONT. CONSEQUENTLY...THUNDERSTORMS MAY TEND TO BE MORE
LINEAR OR MULTI CELL RATHER THAN DISCRETE SUPERCELLS. THE PRIMARY
THREAT WILL BE LARGE HAIL AND DAMAGING WINDS.
HIGH TEMPERATURES SATURDAY WILL BE A DIFFICULT CALL AND GREATLY
DEPEND ON THE PROGRESSION OF THE COLD FRONT AND CLOUD COVER. WOULD
NOT BE SURPRISED TO SEE A FEW 90S ACROSS SOUTHEAST ZONES...WHILE
NORTHWEST ZONES MAY STALL OUT IN THE UPPER 70S TO AROUND 80 BY EARLY
AFTERNOON. TEMPERATURES MAY EVEN FALL A FEW DEGREES BY EARLY TO MID
AFTERNOON FOR AREAS THAT SEE THE EARLIER FRONTAL PASSAGE.
SUNDAY...GREAT DAY BEHIND THE COLD FRONT WITH DRY WEATHER AND HIGHS
IN THE LOWER TO MID 70S
MONDAY AND TUESDAY...EXPECT DRY WEATHER TO CONTINUE WITH A GRADUAL
MODERATING TREND AS A WEAK UPPER RIDGE MOVES ACROSS AREA. HIGHS
SHOULD CLIMB FROM THE 70S ON MONDAY BACK INTO THE 80S BY TUESDAY.
WEDNESDAY AND THURSDAY...AN UPPER LEVEL TROUGH WILL DEEPEN ACROSS
THE NORTHWESTERN CONUS AND MAY BEGIN TO ENHANCE THE FORCING/LIFT
OVER THE CENTRAL PLAINS. THERE IS STILL A GOOD DEAL OF MODEL
UNCERTAINTY WITH THIS SYSTEM AND HOW IT WILL EVOLVE AND PUSH OUT
INTO THE PLAINS. THERE WILL BE AT LEAST SOME THREAT OF
THUNDERSTORMS ACROSS THE CENTRAL OR NORTHERN PLAINS...BUT DIFFICULT
TO GET INTO SPECIFICS AT THIS TIME GIVEN THE MODEL UNCERTAINTY.
TEMPERATURES ARE MORE LIKELY TO BE ABOVE NORMAL IN THE 80S AHEAD OF
THIS NEXT TROUGH.
&&
.AVIATION...12Z KGRI TAF. VFR CONDITIONS TO CONTINUE THROUGH THE
NEXT 24 HOURS...WITH LLWS PERSISTING THROUGH 14Z. THE COMBINATION
OF A SHALLOW LOW LEVEL INVERSION AND A STRONG LOW LEVEL JET IS
PROMOTING SIGNIFICANT LLWS STARTING AROUND 300FT AGL. THIS LLWS
SHOULD DIMINISH BY 14Z AS DIABATIC HEATING ALLOWS FOR DEEPER
BOUNDARY LAYER MIXING...THUS RESULTING IN STRONGER WINDS AT THE
SURFACE AND LESS IN THE WAY OF LLWS. STRONG SURFACE WINDS WILL BE
OBSERVED AT THE TERMINAL ONCE THE BOUNDARY LAYER BEGINS TO
DEEPEN...WITH SUSTAINED SOUTHERLY WINDS OF 24KTS...GUSTING TO
AROUND 34KTS...EXPECTED THIS AFTERNOON. SURFACE WINDS WILL THEN
DIMINISH SOMEWHAT BY SUNSET AS DIABATIC HEATING IS LOST AND THE
BOUNDARY LAYER DECOUPLES FROM THE STRONGER WINDS ALOFT. A SIMILAR
SYNOPTIC SETUP MAY PROMOTE WEAK LLWS AGAIN TONIGHT...HOWEVER IT
DOES NOT APPEAR AS THOUGH THE LOW LEVEL JET WILL BE QUITE AS
STRONG TONIGHT AND WILL GO AHEAD AND LEAVE LLWS OUT OF THE TAF FOR
THE TIME BEING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY UNTIL 9 PM CDT THIS EVENING FOR NEZ060-061-072>074-
082>084.
KS...WIND ADVISORY UNTIL 9 PM CDT THIS EVENING FOR KSZ005-006-017-018.
&&
$$
SHORT...ROSSI
LONG...WESELY
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1100 PM EDT FRI MAY 18 2012
.SYNOPSIS...
TROUGH OF LOW PRESSURE WILL REMAIN STALLED OFFSHORE TONIGHT
BEFORE MOVING NORTHWEST TOWARD THE COAST ON SUNDAY. LOW PRESSURE
WILL CONTINUE TO BRUSH THE COAST THROUGH EARLY NEXT WEEK...BRINGING
RENEWED SHOWERS AND THUNDERSTORMS. THE LOW WILL MOVE NORTHEAST
EARLY TUESDAY...WITH MORE TYPICAL WEATHER FOR THIS TIME OF YEAR
EXPECTED BY MID-WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM FRIDAY...LATEST HRRR CONSOLIDATES THE BROAD SFC LOWS
OFF THE CAROLINA COASTS TO 1 INTENSE CONCENTRIC LOOKING LOW JUST
OFFSHORE FROM THE CAROLINA COASTS OVERNIGHT INTO SATURDAY. LATEST
NAM ALSO FAVORS THIS SOLUTION. SO WITH EGG ON MY FACE...HAVE UPDATED
THE ZONES WITH STRONGER NORTH TO NORTHEAST ACROSS THE FA WITH THE
ADDITION OF GUSTS UP TO AND OVER 20 KT ACROSS THE COASTAL COUNTIES.
BASED ON SURROUNDING 88DS INCLUDING OURS...THE CURRENT LOCATION OF
THE SFC LOW IS ROUGHLY 85 MILES SOUTHEAST OF BALD HEAD ISLAND. LIGHT
RAIN WILL CONTINUE TO TRACK WESTWARD AND PLAGUE THE COASTAL
COUNTIES...WITH THE MAIN CONVECTION STAYING NEAR THE SFC LOW ITSELF.
DO NOT ANTICIPATE ANY ONSHORE MOVEMENT OF THIS CONVECTION.
IN ADDITION TO UPPING THE WINDS...HAVE LOWERED TONIGHTS MINS BY
ATLEAST A CATEGORY. THIS BASED ON LATEST TEMP AND DEWPOINT TRENDS
AND A QUICK LOOK-SEE AT THE 00Z MODEL GUIDANCE.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 2:45 PM FRIDAY...BROAD UPPER LOW NOW CENTERED DIRECTLY OVER
THE COASTAL CAROLINAS WILL BE THE DRIVER FOR THE WEATHER IN THE
SHORT TERM. VARIOUS MID-RANGE GUIDANCE IN GOOD ACCORD AS TO THE
CHARACTER OF THE UPPER LOWS MOVEMENT...A SLOW SPIRAL OFFSHORE ON
SATURDAY...THEN A DRIFT TO THE NORTHWEST AND ONSHORE ON SUNDAY.
GUIDANCE A LITTLE LESS CLEAR AS TO THE PRECIPITATION CONSEQUENCES
AND SURFACE REFLECTIONS FOR THIS FEATURE...ESPECIALLY ON SATURDAY.
NAM IS THE WET SOLUTION WHILE ECMWF AND GFS KEEP THE EASTERN
CAROLINAS ON THE DRY SIDE ON SATURDAY. HAVE LEANED MORE TOWARDS
THE CONSENSUS DRYER SOLUTION FOR SATURDAY...WITH ISOLATED SHOWERS
FOR THE COASTAL COUNTIES AND MINIMAL QPF...YET WITH EXTENSIVE
CLOUD COVER. MORE AGREEMENT BETWEEN GUIDANCE AND HIGHER CONFIDENCE
THAT SUNDAY WILL BE THE WETTER DAY AS THE UPPER LOW AND ITS
SURFACE REFLECTION TRACK BACK NORTHWEST OVER LAND. OMEGA FIELDS
SUGGEST WE COULD ALSO SEE THUNDERSTORMS DEVELOP SUNDAY AFTERNOON
AND EVENING AS CORE OF UPPER LOW MOVES OVERHEAD.
EXTENSIVE CLOUDINESS ON BOTH DAYS AND A STEADY NORTH TO
NORTHEASTERLY FLOW THROUGH THE PERIOD WILL HELP KEEP DAYTIME
TEMPERATURES BELOW NORMAL OVER THE WEEKEND...WITH HIGHS IN THE LOWER
TO MID 70S ALONG THE COAST AND MID TO UPPER 70S INLAND.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 300 PM FRIDAY...MID TO UPPER LOW SITTING DIRECTLY OVERHEAD
EARLY MONDAY WILL LIFT OFF TO THE NORTHEAST MON NIGHT NIGHT INTO
TUES AS ANOTHER SHORTWAVE TROUGH DIGS DOWN OVER THE SOUTHEAST. THIS
TROUGH WILL PUSH A COLD FRONT THROUGH AREA TUES NIGHT INTO WED.
DEPENDING ON TIMING OF EXITING LOW...WE SHOULD SEE A PERIOD OF
SUBSIDENCE BEFORE NEXT SYSTEM COMES. AT THIS POINT IT LOOKS LIKE
TUES MORNING MAY BE DRY WITH A BRIEF PERIOD OF DEEPER NW FLOW AND
SUBSIDENCE ON BACK END OF LOW. PCP WATER DROPS FROM 1.8 INCHES DOWN
TO JUST BELOW 1.5 INCHES BEFORE INCREASING AGAIN IN CONVECTION AHEAD
OF COLD FRONT LATE TUES INTO EARLY WED. ONCE THIS FRONT CLEARS THE
COAST ON WEDNESDAY...IT LOOKS LIKE WEAK HIGH PRESSURE WILL SETTLE
OVER THE AREA THURS AND FRI WITH ONLY LOCALIZED SEA BREEZE
CONVECTION POSSIBLE. DEEP DRY NORTHERLY FLOW ALOFT WILL VEER AROUND
THURS THROUGH FRI WITH MOISTURE MAINLY CONFINED TO 5K FT AND BELOW
FROM THURS INTO NEXT WEEKEND.
WITH CLOUDS AND DEEP LAYER MOISTURE OVER AREA THE FIRST HALF OF THE
WEEK...AND H5 HEIGHTS AROUND 575 DEM...EXPECT TEMPS TO REMAIN BELOW
NORMAL UNTIL LOW LIFTS OFF AND FRONT PASSES BY ON WED. WARMING TREND
WILL BEGIN WED WITH TEMPS REACHING ABOVE NORMAL AS RIDGE BUILDS OVER
THE CAROLINAS FRI THROUGH NEXT WEEKEND.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AS OF 00Z...EXPECT VFR THROUGH VALID PERIOD...WITH EXCEPTION OF
POTENTIAL MVFR DUE TO LOW CIGS EARLY SATURDAY MORNING.
AS STALLED LOW PRESSURE SYSTEM CONTINUES TO SPIN OFF THE CAROLINA
COAST...LIGHT ISOLATED SHOWERS CONTINUE TO MOVE ACROSS THE
AREA...WITH MAJORITY OF RAINFALL JUST OFFSHORE AS DEPICTED BY
CURRENT RADAR IMAGERY. OFFSHORE RAINFALL COULD POTENTIALLY MOVE
ONSHORE THROUGH THE EARLY OVERNIGHT HOURS...BRINGING RAIN TO KILM.
FOR NOW HAVE INTRODUCED TEMPO FOR THIS ACTIVITY THROUGH 3Z AT THE
LATEST. OTHERWISE...EXPECT SCT/BKN HIGH LEVEL CLOUDS THROUGH THE
OVERNIGHT HOURS...WITH NORTHEAST FLOW AOB 10 KTS CONTINUING. LOW
LEVEL STRATUS AOA 1000FT COULD ADVECT INTO THE AREA JUST BEFORE
SUNRISE...BUT ANTICIPATE ANY DEVELOPMENT TO BURN OFF BY MORNING.
NORTHEAST FLOW WILL INCREASE AFTER DAYBREAK WITH SUSTAINED WINDS AOB
12 KTS THROUGHOUT THE DAY AND GUSTS NEAR 20 KTS. CANNOT RULE OUT
ISOLATED TO SCATTERED SHOWERS DURING THE MORNING HOURS...ESPECIALLY
AT THE COASTAL TERMINALS. THROUGHOUT THE DAY///MAY SEE SOME BREAKS
IN THE CLOUDS...BUT OVERALL EXPECT SCT/BKN MID TO HIGH CLOUDS TO
LINGER AS LOW PRESSURE STAYS JUST OFFSHORE. AFTER SUNSET...GUSTS
WILL SUBSIDE ALLOWING FOR NORTHEAST FLOW AOB 10 KTS.
EXTENDED OUTLOOK...MORNING STRATUS POSSIBLE THROUGH SUNDAY...MOSTLY
OVER THE NORTHERN HALF OF THE CWA. POTENTIAL MVFR MONDAY AND
TUESDAY. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 PM FRIDAY...STRONG SCA FOR ALL WATERS CONTINUES THROUGH
SATURDAY AFTERNOON. HAVE UPPED WINDS ACROSS ALL WATERS BASED ON THE
LATEST NAM/HRRR GUIDANCE WHICH ILLUSTRATE A CONSOLIDATED LOW. THE
KLTX 88D INDICATES THIS LOW NOW 85 MILES SOUTHEAST OF BALD HEAD
ISLAND. THE SFC PRESSURE PATTERN AND GRADIENT WILL YIELD NORTH TO
NORTHEAST WINDS 15 TO 25 KT WITH GUSTS UP TO 30 KT INTO SATURDAY
AFTERNOON. THE LATEST HRRR WIND OUTPUT NO LONGER LOOKS OVERDONE WITH
30 TO 40 KT SUSTAINED WINDS OFFSHORE AND CLOSER TO THE SFC LOW.
CORRESPONDING SEAS WILL RANGE FROM 4 TO 7 FT...UP TO 8 AND 9 FT
ACROSS THE OUTER WATERS OFF CAPE FEAR.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 2:45 PM FRIDAY...A GENERALLY NORTHERLY FLOW WILL PREVAIL
THROUGH THE PERIOD AS A TROUGH OF LOW PRESSURE LINGERS EAST OF THE
WATERS. LOW PRESSURE CENTERS DEVELOPING WITHIN THIS TROUGH WILL
TIGHTEN GRADIENTS ENOUGH TO BUMP WINDS UP INTO THE 15 TO 20 KT RANGE
THROUGH DAYTIME SUNDAY. WINDS WILL MODERATE LATER ON SUNDAY AS A LOW
PRESSURE SYSTEM MOVES OVERHEAD. SEAS WILL BE HIGHEST EARLIEST IN THE
PERIOD...WITH 6 FOOTERS LIKELY OVER THE OUTER FRINGES OF OUR WATERS.
WILL KEEP SMALL CRAFT ADVISORY HEADLINES FOR DAYTIME SATURDAY AS A
RESULT. OTHERWISE...SEE 3 TO 5 FT SEAS FOR MUCH OF THE SHORT
TERM...WITH SEAS SUBSIDING LATE ON SUNDAY AS WINDS MODERATE.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 300 PM FRIDAY...WINDS MAY BE A BIT TRICKY ON MONDAY AS LOW
PRESSURE SITS OVERHEAD. MAY RETROGRADE JUST ENOUGH TO THE WEST TO
PRODUCE A LIGHT S-SW FLOW. THIS LOW WILL LIFT OFF TO THE NORTHEAST
LATE MON INTO EARLY TUES WITH A BRIEF VEERING OF THE WINDS BEFORE
NEXT SYSTEM MOVES IN. THE WINDS SHOULD BACK AROUND THROUGH TUES AND
INCREASE SLIGHTLY OUT OF THE W-SW AS COLD FRONT APPROACHES FROM THE
NW. LOOKS LIKE THIS COLD FRONT WILL NOT MAKE A CLEAN SWEEP AND MAY
BECOME WASHED OUT ACROSS THE AREA WITH WEAK GRADIENT FLOW SETTING UP
BY THURS. WINDS WILL MOST LIKELY BE DRIVEN MORE BY LAND/SEA BREEZE
BY THURS. OVERALL EXPECT WINDS 10 KTS OR LESS THROUGH MOST OF THE
PERIOD...EXCEPT UP TO 15 KTS IN TIGHTENED GRADIENT FLOW LATE TUES
THROUGH EARLY WED. SEAS WILL RUN 2 TO 3 FT EXCEPT ON TUES WHEN THEY
INCREASE UP AROUND 4 FT IN OUTER WATERS TUES.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR AMZ250-252-
254-256.
&&
$$
NEAR TERM...DCH
SHORT TERM...REK
LONG TERM...RGZ
AVIATION...DRH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1012 PM EDT FRI MAY 18 2012
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND SOUTHWARD INTO THE CENTRAL CAROLINAS
THROUGH THE WEEKEND...WHILE A LOW PRESSURE SYSTEM STALLS OUT AND
MEANDERS JUST OFFSHORE THE CAROLINA COAST.
&&
.NEAR TERM /TODAY THROUGH SATURDAY NIGHT/...
AS OF 10 PM FRIDAY...
TONIGHT:
SURFACE HIGH PRESSURE CONTINUES TO BUILD/EXTEND INTO CENTRAL NC FROM
THE NORTHEAST THIS EVENING... WHILE A GENERALLY STACK LOW PRESSURE
SYSTEM IS LOCATED OFF THE COAST OF THE CAROLINAS. THIS SETUP AS
ALLOWED DRIER AIR IN THE LOW LEVELS OF THE ATMOSPHERE TO FILTER INTO
THE AREA IN MAINLY NORTH TO NORTHEASTERLY FLOW. MEANWHILE... MAINLY
HIGH LEVEL CLOUD COVER IS STREAMING INTO THE AREA ALOFT FROM SHOWERS
ANS STORMS THE OFFSHORE LOW PRESSURE SYSTEM. GIVEN THE RATHER DRY
AIR CONTINUING TO BUILD INTO THE AREA IN THE LOW LEVELS OF THE
ATMOSPHERE EXPECT DRY CONDITIONS FOR MOST IF NOT ALL OF THE CWA. THE
ONE EXCEPTION MAY BE FROM A FEW VERY LIGHT SHOWERS SKIRTING SOUTHERN
SAMPSON COUNTY THIS EVENING IN ASSOCIATED WITH THE OFFSHORE LOW.
HOWEVER... GIVEN THE LATEST RAP SOUNDINGS FOR SOUTHERN SAMPSON
COUNTIES STILL INDICATE A FAIRLY DRY SUB-CLOUD LAYER BELOW 750 MB
(WITH A DRYING TREND BELOW 750 MB EXPANDING THROUGHOUT THE EVENING)
WILL KEEP THE FORECAST DRY FOR THE ENTIRE AREA. THUS THE MAIN
FORECAST PROBLEM CONTINUES TO BE THE HIGH LEVEL CLOUD COVER AND THE
EFFECTS ON TEMPERATURES. HAVE INCREASED CLOUD COVER FROM THE
PREVIOUS FORECAST AND INCREASED LOW A DEGREE OR TWO... GIVEN CURRENT
OBSERVATIONAL DATA NAM AND GFS FORECAST SOUNDINGS. THIS YIELDS
GENERALLY PARTLY TO MOSTLY CLOUDY SKIES FOR A GOOD PART OF THE
NIGHT... WITH PERHAPS SOME MOSTLY CLEAR CONDITIONS ACROSS THE
WESTERN/NORTHWESTERN PIEDMONT. THUS... WILL GO WITH LOW TEMPS
GENERALLY IN THE LOWER TO MID 50S... WHICH IS NOW GENERALLY IN THE
MIDDLE OF THE STATISTICAL GUIDANCE RANGE.
SATURDAY AND SATURDAY NIGHT:
THE AFOREMENTIONED UPPER LEVEL LOW AND ATTENDANT SURFACE LOW ARE
PROGGED TO STALL JUST OFFSHORE THE CAROLINA COAST THROUGH 12Z SUNDAY
MORNING. MODEL GUIDANCE CONTINUES TO HAVE A DIFFICULT TIME WITH THE
PRECISE EVOLUTION OF THESE FEATURES...THOUGH NEITHER MODEL INDICATES
MORE THAN A TRACE OF PRECIP IN THE FAR EAST/SE COASTAL PLAIN THROUGH
SUNRISE SUNDAY MORNING. HOWEVER...THIS SYSTEM IS EXPECTED TO BECOME
MORE PROGRESSIVE DURING THE DAY SUNDAY...RETROGRADING ONSHORE INTO
EASTERN NC...AND IF THE SURFACE/UPPER LEVEL LOW RETROGRADE A BIT
SOONER THAN CURRENTLY PROGGED...LIGHT SHOWERS WOULD BE POSSIBLE EAST
OF THE I-95 CORRIDOR PRIOR TO SUNRISE SUNDAY MORNING. WITH THE ABOVE
IN MIND...WILL KEEP THE FCST DRY ON SATURDAY...AND WILL INDICATE A
SLIGHT CHANCE OF SHOWERS OR SPRINKLES IN THE COASTAL PLAIN AFTER
MIDNIGHT. THE AIRMASS ACROSS CENTRAL NC WILL VARY FROM VERY DRY IN
THE WESTERN PIEDMONT (0.50" PWAT AT GSO) TO MOIST IN THE COASTAL
PLAIN (PWAT 1.15" AT RWI) ON SATURDAY. EXPECT SUNNY OR MOSTLY SUNNY
SKIES IN THE WEST...AND PARTLY CLOUDY TO MOSTLY CLOUDY SKIES IN THE
EAST. EXPECT HIGHS ON SATURDAY TO BE SLIGHTLY WARMER THAN TODAY IN
THE WESTERN PIEDMONT (MID/UPPER 70S)...AND SIMILAR OR SLIGHTLY
COOLER THAN TODAY IN THE FAR EASTERN COASTAL PLAIN (LOWER 70S). LOWS
SAT NIGHT IN THE LOWER/MID 50S. -VINCENT
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 100 PM FRIDAY...
THE FORECAST WILL HINGE ON THE EVENTUAL FATE/EVOLUTION OF THE
MEANDERING CLOSED UPPER LOW AND ASSOCIATED LOW PRESSURE CENTER OFF
THE NORTH CAROLINA COAST. OVERALL...THE GUIDANCE ENVELOPE HAS
SHIFTED SLIGHTLY WESTWARD/INLAND FOR SUNDAY AND MONDAY...BUT THERE
REMAINS SIGNIFICANT SPREAD WITH THE TIMING AND HOW FAR INLAND THIS
SYSTEM WILL RETROGRADE.
IF CURRENT TRENDS HOLD UP...EXPECT THICKENING CLOUD COVER WITH
INCREASING RAIN CHANCES SUNDAY AFTERNOON/EVENING...AND CONTINUING
INTO THE DAY ON MONDAY AS THE EASTERLY ATLANTIC MARITIME FEED WILL
ADVECT HIGH PWATS ON THE ORDER 1.5-1.6"(2 SD ABOVE NORMAL)INLAND AS
THE CIRCULATION CENTER WOBBLES WESTWARD OVER THE FORECAST AREA.
EXPECT THAT WE WILL SEE A DIURNAL ENHANCEMENT IN POPS/CONVECTION...
SUNDAY AFTERNOON/EVENING AND AGAIN MONDAY AFTERNOON BEFORE THE
LOW BEGINS TO FINALLY TRANSLATE EASTWARD MONDAY EVENING/NIGHT WITH
THE APPROACH OF THE NORTHERN STREAM TROUGH FROM THE WEST. THERE
REMAINS TOO MUCH UNCERTAINTY AT THIS TIME TO DISCUSS IN DETAIL
ABOUT ANY SEVERE/HEAVY RAIN THREAT...BUT WILL NEED TO MONITOR
THE NEXT DAY OR TWO GIVEN RECENT HEAVY RAINS ACROSS CENTRAL AND
EASTERN NC. FOR THE SAME REASONS...WILL KEEP POPS IN THE SLIGHT TO
CHANCE CATEGORIES FOR NOW...WITH HIGHEST POPS IN THE EAST. WITH
TIME...BUT IF LATER MODEL RUNS START TO EXHIBIT BETTER CONTINUITY...
SUNDAY NIGHT AND INTO MONDAY COULD BE A WET PERIOD WITH LIKELY TO
CATEGORICAL POPS.
SEASONABLE TEMPERATURES SUNDAY THROUGH MONDAY...HIGHLY DEPENDENT ON
THE UPPER LOW AND ASSOCIATED RAIN CHANCES. GIVEN THE WESTWARD TREND
WITH THE LOW PRESSURE SYSTEM WILL NUDGE FORECAST HIGHS SUNDAY
AND MONDAY DOWN A BIT...HIGHS GENERALLY IN THE MID TO UPPER 70S.
LOWS 55 TO 60. -CBL
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 245 PM FRIDAY...
THERE ARE SOME PRETTY GLARING DIFFERENCES WITH THE TIMING AND
AMPLITUDE OF THE NEXT SHORTWAVE TROUGH AND ATTENDANT SURFACE FRONT
MOVING EAST THROUGH THE REGION DURING THE TUESDAY THROUGH
WEDNESDAY PERIOD. THE GFS IS UP TO ITS USUAL TRICKS/BIAS...
RACING THE OPEN WAVE TROUGH EASTWARD THROUGH THE AREA TUESDAY
EVENING/NIGHT...WHILE THE EC IS MORE SLOWER TO ADVANCE THE SYSTEM
EASTWARD...DEVELOPING INTO A CLOSED LOW INVOF OF THE OHIO/TN VALLEY
BEFORE FINALLY CROSSING THE AREA ON THURSDAY. UNTIL THERE IS BETTER
MODEL AGREEMENT WILL BROAD BRUSH SLIGHT TO SMALL CHANCE POPS ACROSS
THE AREA TUESDAY-WEDNESDAY WITH DRY CONDITIONS AFTERWORDS.
MODERATING TEMPERATURES IN THE LOW-LEVEL SWLY FLOW. HIGHS IN THE
LOWER TO MID 80S. LOWS IN THE 60S.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AS OF 745 PM FRIDAY...
24-HR TAF PERIOD:
DESPITE CONSIDERABLE CLOUD COVERAGE OVER THE REGION ASSOCIATED WITH
THE TROUGH ALONG THE CAROLINA COAST...MUCH OF THIS CLOUDINESS IS MID
AND HIGH LEVEL WITH LOW CLOUDS CONFINED MAINLY ALONG THE COAST.
GUIDANCE SHOWS LITTLE CHANGE OVERNIGHT THUS WILL CONTINUE WITH VFR
CONDITIONS FEATURING BKN HIGH LAYER CLOUDS AND LIGHT NE SFC WINDS.
LATER TONIGHT CAN`T RULE OUT A BRIEF PERIOD OF MVFR CIGS AT OUR
EASTERN TAF SITES...BUT GIVEN CURRENT TRENDS THATS LOOKING LESS
LIKELY NOW. AFTER SUNRISE SATURDAY...MODELS BEGIN TO SHOW THE SFC
LOW OFF THE COAST BEGINNING TO GRADUALLY DRIFT WEST. THUS EXPECT THE
NE WINDS TO PICK UP TO 10G20KT AND GRADUALLY INCREASING 3-5K FT
CLOUDS ALONG OUR COASTAL PLAIN.
LOOKING AHEAD:
EXPECT INCREASING CHANCES FOR MVFR (PERHAPS IFR) CEILINGS SATURDAY
NIGHT INTO SUNDAY MORNING AS THE AFOREMENTIONED SURFACE AND UPPER
LEVEL LOW BEGINS TO RETROGRADE TOWARD THE COASTAL CAROLINAS...
FOLLOWED BY INCREASING CHANCES FOR SHOWERS AND CONTINUED MVFR
(PERHAPS IFR) CONDITIONS SUNDAY INTO SUNDAY NIGHT. THE RELATIVE
WORSE CONDITIONS WOULD BE AT THE FAY/RWI TERMINALS...FOLLOWED BY
RDU...AND FINALLY RWI. QUITE A BIT OF UNCERTAINTY PERSISTS IN THE
FORECAST FOR EARLY NEXT WEEK...AND AT THIS TIME IT APPEARS THAT MVFR
CONDITIONS AND CHANCES FOR SHOWERS WILL PERSIST THROUGH EARLY NEXT
WEEK AND POSSIBLE INTO THE MIDDLE OF NEXT WEEK. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...BSD/VINCENT
SHORT TERM...CBL
LONG TERM...CBL
AVIATION...NP/VINCENT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
800 PM EDT FRI MAY 18 2012
.SYNOPSIS...
TROUGH OF LOW PRESSURE WILL REMAIN STALLED OFFSHORE TONIGHT
BEFORE MOVING NORTHWEST TOWARD THE COAST ON SUNDAY. LOW PRESSURE
WILL CONTINUE TO BRUSH THE COAST THROUGH EARLY NEXT WEEK...BRINGING
RENEWED SHOWERS AND THUNDERSTORMS. THE LOW WILL MOVE NORTHEAST
EARLY TUESDAY...WITH MORE TYPICAL WEATHER FOR THIS TIME OF YEAR
EXPECTED BY MID-WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 755 PM FRIDAY...LATEST HRRR CONSOLIDATES THE BROAD SFC LOW OFF
THE CAROLINA COASTS TO 1 INTENSE CONCENTRIC LOOKING LOW JUST
OFFSHORE FROM THE CAROLINA COASTS BY DAYBREAK SATURDAY. THIS SFC LOW
LOOKS WELL OVERDONE INTENSITY-WISE BUT ITS LOCATION IS BELIEVABLE
CONSIDERING IT IDENTIFIES THE CURRENT LOW OFFSHORE FROM CAPE FEAR AT
INIT. TIME. BASED ON SURROUNDING 88DS INCLUDING OURS...WILL UP POPS
ALONG THE IMMEDIATE COAST AND ATL WATERS. POPS WILL DECREASE
CONSIDERABLY AS A SHARP GRADIENT EXTENDING INLAND. MODEL SOUNDINGS
INDICATE THE POSSIBILITY OF LOW STRATUS LATE TONIGHT WITH AN OVERALL
OVERCAST SKY. COULD OBSERVE A FEW BREAKS WEST OF THE I95 CORRIDOR IF
ONE BELIEVES THE EUROPEAN MOISTURE PROFILE. CONTINUED WITH LATEST
MIN TEMP FORECAST WHICH KEEPS THE FA AT OR SLIGHTLY ABOVE CLIMO.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 2:45 PM FRIDAY...BROAD UPPER LOW NOW CENTERED DIRECTLY OVER
THE COASTAL CAROLINAS WILL BE THE DRIVER FOR THE WEATHER IN THE
SHORT TERM. VARIOUS MID-RANGE GUIDANCE IN GOOD ACCORD AS TO THE
CHARACTER OF THE UPPER LOWS MOVEMENT...A SLOW SPIRAL OFFSHORE ON
SATURDAY...THEN A DRIFT TO THE NORTHWEST AND ONSHORE ON SUNDAY.
GUIDANCE A LITTLE LESS CLEAR AS TO THE PRECIPITATION CONSEQUENCES
AND SURFACE REFLECTIONS FOR THIS FEATURE...ESPECIALLY ON SATURDAY.
NAM IS THE WET SOLUTION WHILE ECMWF AND GFS KEEP THE EASTERN
CAROLINAS ON THE DRY SIDE ON SATURDAY. HAVE LEANED MORE TOWARDS
THE CONSENSUS DRYER SOLUTION FOR SATURDAY...WITH ISOLATED SHOWERS
FOR THE COASTAL COUNTIES AND MINIMAL QPF...YET WITH EXTENSIVE
CLOUD COVER. MORE AGREEMENT BETWEEN GUIDANCE AND HIGHER CONFIDENCE
THAT SUNDAY WILL BE THE WETTER DAY AS THE UPPER LOW AND ITS
SURFACE REFLECTION TRACK BACK NORTHWEST OVER LAND. OMEGA FIELDS
SUGGEST WE COULD ALSO SEE THUNDERSTORMS DEVELOP SUNDAY AFTERNOON
AND EVENING AS CORE OF UPPER LOW MOVES OVERHEAD.
EXTENSIVE CLOUDINESS ON BOTH DAYS AND A STEADY NORTH TO
NORTHEASTERLY FLOW THROUGH THE PERIOD WILL HELP KEEP DAYTIME
TEMPERATURES BELOW NORMAL OVER THE WEEKEND...WITH HIGHS IN THE LOWER
TO MID 70S ALONG THE COAST AND MID TO UPPER 70S INLAND.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 300 PM FRIDAY...MID TO UPPER LOW SITTING DIRECTLY OVERHEAD
EARLY MONDAY WILL LIFT OFF TO THE NORTHEAST MON NIGHT NIGHT INTO
TUES AS ANOTHER SHORTWAVE TROUGH DIGS DOWN OVER THE SOUTHEAST. THIS
TROUGH WILL PUSH A COLD FRONT THROUGH AREA TUES NIGHT INTO WED.
DEPENDING ON TIMING OF EXITING LOW...WE SHOULD SEE A PERIOD OF
SUBSIDENCE BEFORE NEXT SYSTEM COMES. AT THIS POINT IT LOOKS LIKE
TUES MORNING MAY BE DRY WITH A BRIEF PERIOD OF DEEPER NW FLOW AND
SUBSIDENCE ON BACK END OF LOW. PCP WATER DROPS FROM 1.8 INCHES DOWN
TO JUST BELOW 1.5 INCHES BEFORE INCREASING AGAIN IN CONVECTION AHEAD
OF COLD FRONT LATE TUES INTO EARLY WED. ONCE THIS FRONT CLEARS THE
COAST ON WEDNESDAY...IT LOOKS LIKE WEAK HIGH PRESSURE WILL SETTLE
OVER THE AREA THURS AND FRI WITH ONLY LOCALIZED SEA BREEZE
CONVECTION POSSIBLE. DEEP DRY NORTHERLY FLOW ALOFT WILL VEER AROUND
THURS THROUGH FRI WITH MOISTURE MAINLY CONFINED TO 5K FT AND BELOW
FROM THURS INTO NEXT WEEKEND.
WITH CLOUDS AND DEEP LAYER MOISTURE OVER AREA THE FIRST HALF OF THE
WEEK...AND H5 HEIGHTS AROUND 575 DEM...EXPECT TEMPS TO REMAIN BELOW
NORMAL UNTIL LOW LIFTS OFF AND FRONT PASSES BY ON WED. WARMING TREND
WILL BEGIN WED WITH TEMPS REACHING ABOVE NORMAL AS RIDGE BUILDS OVER
THE CAROLINAS FRI THROUGH NEXT WEEKEND.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AS OF 00Z...EXPECT VFR THROUGH VALID PERIOD...WITH EXCEPTION OF
POTENTIAL MVFR DUE TO LOW CIGS EARLY SATURDAY MORNING.
AS STALLED LOW PRESSURE SYSTEM CONTINUES TO SPIN OFF THE CAROLINA
COAST...LIGHT ISOLATED SHOWERS CONTINUE TO MOVE ACROSS THE
AREA...WITH MAJORITY OF RAINFALL JUST OFFSHORE AS DEPICTED BY
CURRENT RADAR IMAGERY. OFFSHORE RAINFALL COULD POTENTIALLY MOVE
ONSHORE THROUGH THE EARLY OVERNIGHT HOURS...BRINGING RAIN TO KILM.
FOR NOW HAVE INTRODUCED TEMPO FOR THIS ACTIVITY THROUGH 3Z AT THE
LATEST. OTHERWISE...EXPECT SCT/BKN HIGH LEVEL CLOUDS THROUGH THE
OVERNIGHT HOURS...WITH NORTHEAST FLOW AOB 10 KTS CONTINUING. LOW
LEVEL STRATUS AOA 1000FT COULD ADVECT INTO THE AREA JUST BEFORE
SUNRISE...BUT ANTICIPATE ANY DEVELOPMENT TO BURN OFF BY MORNING.
NORTHEAST FLOW WILL INCREASE AFTER DAYBREAK WITH SUSTAINED WINDS AOB
12 KTS THROUGHOUT THE DAY AND GUSTS NEAR 20 KTS. CANNOT RULE OUT
ISOLATED TO SCATTERED SHOWERS DURING THE MORNING HOURS...ESPECIALLY
AT THE COASTAL TERMINALS. THROUGHOUT THE DAY///MAY SEE SOME BREAKS
IN THE CLOUDS...BUT OVERALL EXPECT SCT/BKN MID TO HIGH CLOUDS TO
LINGER AS LOW PRESSURE STAYS JUST OFFSHORE. AFTER SUNSET...GUSTS
WILL SUBSIDE ALLOWING FOR NORTHEAST FLOW AOB 10 KTS.
EXTENDED OUTLOOK...MORNING STRATUS POSSIBLE THROUGH SUNDAY...MOSTLY
OVER THE NORTHERN HALF OF THE CWA. POTENTIAL MVFR MONDAY AND
TUESDAY. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 8 PM FRIDAY...SCA FOR ALL WATERS CONTINUES INTO SATURDAY
AFTERNOON. WILL CONTINUE WITH THE CURRENT WIND REGIME WHICH
HIGHLIGHTS A SFC PRESSURE PATTERN AND GRADIENT THAT YIELDS N TO NE
WINDS 15 TO 25 KT OVERNIGHT INTO SATURDAY. THE LATEST HRRR WIND
OUTPUT LOOKS WAY OVERDONE WITH 30 TO 40 KT SUSTAINED JUST OFFSHORE
FROM CAPE FEAR. WILL FORECAST SEAS RANGING FROM 3 TO 6 FT...WITH THE
HIGHER SEAS ACROSS THE OUTER WATERS OFF CAPE FEAR.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 2:45 PM FRIDAY...A GENERALLY NORTHERLY FLOW WILL PREVAIL
THROUGH THE PERIOD AS A TROUGH OF LOW PRESSURE LINGERS EAST OF THE
WATERS. LOW PRESSURE CENTERS DEVELOPING WITHIN THIS TROUGH WILL
TIGHTEN GRADIENTS ENOUGH TO BUMP WINDS UP INTO THE 15 TO 20 KT RANGE
THROUGH DAYTIME SUNDAY. WINDS WILL MODERATE LATER ON SUNDAY AS A LOW
PRESSURE SYSTEM MOVES OVERHEAD. SEAS WILL BE HIGHEST EARLIEST IN THE
PERIOD...WITH 6 FOOTERS LIKELY OVER THE OUTER FRINGES OF OUR WATERS.
WILL KEEP SMALL CRAFT ADVISORY HEADLINES FOR DAYTIME SATURDAY AS A
RESULT. OTHERWISE...SEE 3 TO 5 FT SEAS FOR MUCH OF THE SHORT
TERM...WITH SEAS SUBSIDING LATE ON SUNDAY AS WINDS MODERATE.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 300 PM FRIDAY...WINDS MAY BE A BIT TRICKY ON MONDAY AS LOW
PRESSURE SITS OVERHEAD. MAY RETROGRADE JUST ENOUGH TO THE WEST TO
PRODUCE A LIGHT S-SW FLOW. THIS LOW WILL LIFT OFF TO THE NORTHEAST
LATE MON INTO EARLY TUES WITH A BRIEF VEERING OF THE WINDS BEFORE
NEXT SYSTEM MOVES IN. THE WINDS SHOULD BACK AROUND THROUGH TUES AND
INCREASE SLIGHTLY OUT OF THE W-SW AS COLD FRONT APPROACHES FROM THE
NW. LOOKS LIKE THIS COLD FRONT WILL NOT MAKE A CLEAN SWEEP AND MAY
BECOME WASHED OUT ACROSS THE AREA WITH WEAK GRADIENT FLOW SETTING UP
BY THURS. WINDS WILL MOST LIKELY BE DRIVEN MORE BY LAND/SEA BREEZE
BY THURS. OVERALL EXPECT WINDS 10 KTS OR LESS THROUGH MOST OF THE
PERIOD...EXCEPT UP TO 15 KTS IN TIGHTENED GRADIENT FLOW LATE TUES
THROUGH EARLY WED. SEAS WILL RUN 2 TO 3 FT EXCEPT ON TUES WHEN THEY
INCREASE UP AROUND 4 FT IN OUTER WATERS TUES.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR AMZ250-252-
254-256.
&&
$$
NEAR TERM...DCH
SHORT TERM...REK
LONG TERM...RGZ
AVIATION...DRH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
645 PM CDT FRI MAY 18 2012
.DISCUSSION...
AS OF 2330 UTC...THE CONVECTIVE ACTIVITY THAT INITIATED IN THE
BISMARCK...MANDAN VICINITY WAS QUICKLY EXITING THE CWA INTO
NORTHEAST NORTH DAKOTA...WITH AN AREA OF LIGHT RAIN ACROSS THE
NORTHWEST IN ASSOCIATION WITH A SURFACE TROUGH AND BETTER FORCING
FROM THE UPPER LEVEL WAVE. FURTHER EAST...A COLD FRONT WAS LOCATED
FROM FAR NORTHWEST MINNESOTA...PASSING IN BETWEEN JAMESTOWN AND
VALLEY CITY EXTENDING INTO SOUTH CENTRAL SOUTH DAKOTA. THE 23 UTC
SPC MESOANALYSIS DEPICTED 1000-1500 J/KG OF ML CAPE CENTERED JUST
ON THE COOL SIDE OF THE FRONT ACROSS NORTH DAKOTA WITH 35-40 KTS
OF DEEP LAYER SHEAR. HOWEVER...CINH HAS ALSO INCREASED OVER THE
PAST HOUR. THERE MAY BE A BRIEF WINDOW BEFORE SUNSET FOR SURFACE
BASED INITIATION ALONG THE BOUNDARY...HOWEVER...CONFIDENCE IS
DECREASING AS SUPPORTED BY THE LATEST HRRR RUNS.
THE BEST PRECIPITATION CHANCES FOR WESTERN AND CENTRAL NORTH
DAKOTA SHOULD COME AFTER 06 UTC AS CONVECTION ACROSS SOUTHWEST
SOUTH DAKOTA AND INTO NEBRASKA LIFTS NORTHEAST AND CONGEALS.
INCREASED POPS ALONG AND EAST OF HIGHWAY 85 TO 100 PERCENT FOR
MOST AREAS. THE BEST CHANCES FOR THUNDER POST 06 UTC WILL BE
ACROSS THE TURTLE MOUNTAINS THROUGH THE JAMES RIVER VALLEY WHERE
THE BEST ELEVATED CAPE WILL RESIDE. FURTHER WEST...BUFR SOUNDINGS
INDICATED NEARLY SATURATED PROFILES WITH LITTLE CAPE AND
WEAKENING MID LEVEL LAPSE RATES...MORE SUPPORTIVE OF MODERATE TO
HEAVY RAIN.
&&
.AVIATION...
AS OF 2330 UTC...A COLD FRONT WAS LOCATED FROM NEAR KHCO HALLOCK
MINNESOTA TO JUST EAST OF KJMS THROUGH SOUTH CENTRAL SOUTH DAKOTA.
THERE IS DECREASING CONFIDENCE FOR STORMS TO INITIATE ALONG THIS
FRONT BEFORE SUNSET IN NORTH DAKOTA...WITH THE BEST CHANCES FOR
PRECIPITATION AFTER 06 UTC AS SHOWERS AND STORMS ACROSS SOUTH
DAKOTA AND NEBRASKA LIFT NORTHEAST. MVFR CEILINGS ARE POSSIBLE IN
WIDESPREAD RAIN SHOWERS TONIGHT ACROSS WESTERN AND CENTRAL NORTH
DAKOTA WITH EMBEDDED THUNDERSTORMS ACROSS THE CENTRAL. WINDS WILL
TRANSITION TO THE NORTHWEST TONIGHT WITH GUSTS TO 25 KTS POSSIBLE
BY 12 UTC AT ALL TAF SITES.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE/AVIATION...AYD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1035 PM EDT FRI MAY 18 2012
.SYNOPSIS...
A WARM AND TRANQUIL WEEKEND IS IN STORE FOR THE AREA AS A DEEP
LAYERED RIDGE OF HIGH PRESSURE MOVES ACROSS OHIO INTO INTERIOR NEW
ENGLAND BY LATER ON SUNDAY. WEAK EASTERLY FLOW AT THE SURFACE WILL
HOLD DEEPER MOISTURE AT BAY...BUT HUMIDITIES WILL BE ON THE
INCREASE OVER WHAT HAS BEEN EXPERIENCED THE PREVIOUS FEW DAYS. A
WEAKENING WEATHER SYSTEM SHIFTING THROUGH THE WESTERN GREAT LAKES
SUNDAY NIGHT WILL SLOW AS IT MOVES INTO THE OHIO VALLEY...BRINGING
THE NEXT THREAT OF SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
DESPITE VERY WEAK NEAR-SURFACE WIND FLOW...MOISTURE IS INCREASING
FROM SOUTHEAST TO NORTHWEST ACROSS THE FORECAST AREA AT THIS TIME.
WITH THE MOSTLY CALM WINDS AND CLEAR SKIES...SOME FOG SEEMS LIKELY
IN PRONE AREAS...AND PATCHY REDUCED VISIBILITIES ARE POSSIBLE
ELSEWHERE AS WELL. ADDED SLIGHTLY MORE LOW-ELEVATION FOG THAN THE
PREVIOUS FORECAST...AND MADE SOME MINOR ADJUSTMENTS TO MIN TEMPS
AS WELL.
PREVIOUS DISCUSSION >
AMPLE SUNSHINE AGAIN TODAY WITH LOW DEWPOINTS /30S AND
40S/...THANKS TO DEEP LAYERED RIDGE OF HIGH PRESSURE OVER THE
AREA. 18.19Z RUC ANALYSIS INDICATED A CLOSED-CONTOUR 580DM
ANTICYCLONE OVER NRN INDIANA...ATOP A CLOSED-CONTOUR 576DM CYCLONE
JUST OFF THE SOUTH CAROLINA COAST. NOT OVER STRONG/IMPRESSIVE
SYSTEMS...BUT THIS REX BLOCK TYPE STRUCTURE WILL CONTINUE TO
DOMINATE OUR WEEKEND WEATHER PATTERN...WITH WEAK EASTERLY FLOW OUT
OF A SURFACE HIGH PRESSURE SYSTEM IN NEW ENGLAND /RATHER BAGGY
PRESSURE GRADIENT/ CONTINUING TO HOLD DEEPER BOUNDARY LAYER
MOISTURE /60S DEWPOINTS/ WELL SOUTH AND WEST OF THE AREA.
IN THE UPCOMING 12-15 HOURS...EXPECT VERY LITTLE SYNOPTIC SCALE
CHANGE AS THE MID-LEVEL HIGH DRIFTS THROUGH NRN OHIO AND
STRENGTHENS SLIGHTLY WHILE THE LOW OVER THE WRN ATL ELONGATES SOME
BEGINS SPLITTING INTO TWO DISTINCT CYCLONIC CIRCULATION
CENTERS...ONE IN ERN GA AND THE OTHER OFF THE NC COAST.
VERY WEAK SFC FLOW WILL QUICKLY GO CALM THIS EVENING UNDER RAPIDLY
STRENGTHENING INVERSION AND DECOUPLING OF THE SHALLOWING BOUNDARY
LAYER. THIS SHOULD FOSTER A RAPID EVENING TEMP DROP WITH CLEAR
SKIES. RAN A GENERAL BLEND OF THE PREVIOUS FORECAST AND 12Z
ECMWF/GFS/NAM MOS...THOUGH TWEAKED A TOUCH DOWNWARD IN THE COOL
SPOTS GIVEN IDEAL RADIATIONAL COOLING REGIME. ALSO FOGGED UP THE
OHIO AND ADJACENT RIVER VALLEYS LATER IN THE NIGHT...AS BOUNDARY
LAYER MOISTURE FROM KY WILL BE SEEPING NWRD OVERNIGHT AS MINOR SLY
COMPONENT TO THE GENERAL EASTERLY FLOW WILL ALLOW AN INCREASE IN
LLVL MOISTURE. WOULD NOT BE SURPRISED IS FOG BECOMES A LITTLE MORE
WIDESPREAD THAN FORECAST ESP OVER NRN KY/SRN OH/SERN IND.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
VERY LITTLE CHANGE TO THE PATTERN ALOFT ON SATURDAY...THOUGH THE
LOW LEVELS WILL BEGIN TO UNDERGO SOME MOISTURE ADVECTION...ESPECIALLY
ACROSS SRN/SWRN FORECAST AREA. 18.12Z WRF/GFS INDICATE LOWEST 1KM
SPECIFIC HUMIDITIES DOUBLING IN COMPARISON TO FRIDAY...SO BROUGHT
DEWPOINTS UP A BIT IN THE SOUTH/SOUTHWEST...PERHAPS NOT ENOUGH.
FEEL 18.12Z NAM-WRF SFC DWPTS ABOUT 10F TOO HIGH AS HAS BEEN A
PROBLEM THIS SPRING...SO DISCOUNTING THE RATHER STRONG INSTBY THAT
DEVELOPS UNDERNEATH THE MID LEVEL RIDGE SATURDAY AFTERNOON. EVEN
SO...ADDITIONAL MOISTURE AND A FAVORABLE LAPSE RATE WILL NO DOUBT
YIELD SOME DEEPER CUMULUS ACROSS THE SOUTH/SOUTHWEST...BUT THINK
NIL FORCING AND CONTINUED RISING HEIGHTS WILL MITIGATE A NEED FOR
A RAIN CHANCE AT THIS TIME. A WARM DAY...AND MOS SHOULD PERFORM
WELL IN THIS RATHER PREDICTABLE REGIME...SO AGAIN BLENDED PREVIOUS
FORECAST WITH MOST RECENT VALUES. SPOT CHECK OF LOW LEVEL
THICKNESS CONSIDERATIONS AND MIXING TO 850-825MB /DESPITE VERY
WEAK FLOW/ SUGGESTS WIDESPREAD LOWER TO MIDDLE 80S...VERY MUCH IN
LINE WITH THE BLEND.
LIKELY A REPEAT SCENARIO SATURDAY NIGHT WITH VALLEY FOG...AND
LOWS IN THE 50S.
SUNDAY IS A CARBON-COPY OF SATURDAY. DISTINCT CIRCULATION CENTERS
ATTENDANT TO THE SOUTHEAST CONUS TROUGH RECOMBINE OVER THE OUTER
BANKS OF NC WHILE THE MID LEVEL ANTICYCLONE CONTINUES TO DEEPEN TO
585DM OVER INTERIOR NEW ENGLAND. THIS WILL REINFORCE A LOW LEVEL
EASTERLY TRAJECTORY...THUS DON/T EXPECT MUCH /IF ANY/ DEWPOINT
RISE ON SUNDAY...AND TEMPERATURES SHOULD HOLD VERY SIMILAR TO
SATURDAY/S READINGS. PROBABLY A THICKER CIRRUS SHIELD PER BUFR
SOUNDINGS...BUT THAT WOULD BE ABOUT THE EXTENT OF SENSIBLE
WEATHER.
SUNDAY NIGHT BEGINS TO SEE SOME CHANGE AS A TROUGH OF LOW PRESSURE
/DAMPENING OUT AND SLOWING AS IT ENCOUNTERS THE BLOCKY FLOW ALONG THE
EAST COAST/ APPROACHES THE GREAT LAKES. HAVE KEPT THE NIGHTTIME
DRY AT THIS POINT AS 18.12Z GUIDANCE WAFFLING ON WEAK/MID LEVEL-
BASED SHOWERS AND STORM PLACEMENT AS FORCING SLOWLY INCREASES
LATER IN THE NIGHT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
PERIOD OF DRY WEATHER MAY COME TO AN END MONDAY AS MOISTURE AND
INSTABILITY INCREASE AHEAD OF AN UPPER TROUGH. WITH THE ECMWF AND
GFS COMING INTO FAIR AGREEMENT...KEPT A CHANCE OF THUNDERSTORMS FOR
MONDAY...MAINLY IN WESTERN COUNTIES THAT WILL BE AFFECTED MORE BY
SURFACE CONVERGENCE AND COOLER AIR ALOFT.
STAYED CLOSE TO ECMWF SOLUTION FOR TUESDAY SINCE IT CONTINUES TO
SHOW A CLOSED UPPER LOW FORMING AS OPPOSED TO THE FASTER OPEN WAVE
DEPICTED ON THE GFS. AS THE UPPER LOW FORMS NEAR CVG...THERE WILL BE
A GOOD CHANCE FOR THUNDERSTORMS UNDER A COOL POOL ALOFT COUPLED WITH
DEEP MOISTURE ADVECTION FROM THE SOUTH.
THUNDERSTORMS CHANCES WILL DIMINISH ON WEDNESDAY AS THE CLOSED UPPER
LOW SLIPS EAST ALLOWING DRIER AND MORE STABLE AIR TO WORK IN. THE
DRY CONDITIONS ARE EXPECTED TO CONTINUE ON THURSDAY AND FRIDAY WHEN
RIDGING ALOFT IS FORECAST TO MOVE BACK IN.
HIGH TEMPERATURES WILL BE MAINLY IN THE 80S MONDAY ON THE EAST SIDE
OF THE UPPER TROUGH. COOLER READINGS IN THE 70S ARE FORECAST AS THE
CLOSED LOW MAKES ITS WAY ACROSS THE AREA WITH ASSOCIATED CLOUD COVER
AND COLD ADVECTION. LOOK FOR A REBOUND TO THE 80S BY FRIDAY AS
SUNSHINE AND WARM ADVECTION RETURN.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
HIGH PRESSURE WILL MAINTAIN CONTROL OF THE WEATHER THROUGH THE TAF
PERIOD. LOW LEVEL MOISTURE WILL BE INCREASING OVER THE NEXT DAY OR
SO...WHICH WILL ALLOW FOR SOME CUMULUS DEVELOPMENT TOMORROW.
OVERNIGHT TONIGHT...IT MAY ALLOW FOR SOME FOG TO DEVELOP AT THE
CINCINNATI TAF SITES (INCLUDING LIFR AT KLUK). WINDS WILL REMAIN
FAIRLY LIGHT THROUGH THE PERIOD...AND GENERALLY OUT OF THE ESE.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE MONDAY AND TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...BINAU
NEAR TERM...BINAU/HATZOS
SHORT TERM...BINAU
LONG TERM...CONIGLIO
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
734 PM EDT FRI MAY 18 2012
.SYNOPSIS...
A WARM AND TRANQUIL WEEKEND IS IN STORE FOR THE AREA AS A DEEP
LAYERED RIDGE OF HIGH PRESSURE MOVES ACROSS OHIO INTO INTERIOR NEW
ENGLAND BY LATER ON SUNDAY. WEAK EASTERLY FLOW AT THE SURFACE WILL
HOLD DEEPER MOISTURE AT BAY...BUT HUMIDITIES WILL BE ON THE
INCREASE OVER WHAT HAS BEEN EXPERIENCED THE PREVIOUS FEW DAYS. A
WEAKENING WEATHER SYSTEM SHIFTING THROUGH THE WESTERN GREAT LAKES
SUNDAY NIGHT WILL SLOW AS IT MOVES INTO THE OHIO VALLEY...BRINGING
THE NEXT THREAT OF SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AMPLE SUNSHINE AGAIN TODAY WITH LOW DEWPOINTS /30S AND
40S/...THANKS TO DEEP LAYERED RIDGE OF HIGH PRESSURE OVER THE
AREA. 18.19Z RUC ANALYSIS INDICATED A CLOSED-CONTOUR 580DM
ANTICYCLONE OVER NRN INDIANA...ATOP A CLOSED-CONTOUR 576DM CYCLONE
JUST OFF THE SOUTH CAROLINA COAST. NOT OVER STRONG/IMPRESSIVE
SYSTEMS...BUT THIS REX BLOCK TYPE STRUCTURE WILL CONTINUE TO
DOMINATE OUR WEEKEND WEATHER PATTERN...WITH WEAK EASTERLY FLOW OUT
OF A SURFACE HIGH PRESSURE SYSTEM IN NEW ENGLAND /RATHER BAGGY
PRESSURE GRADIENT/ CONTINUING TO HOLD DEEPER BOUNDARY LAYER
MOISTURE /60S DEWPOINTS/ WELL SOUTH AND WEST OF THE AREA.
IN THE UPCOMING 12-15 HOURS...EXPECT VERY LITTLE SYNOPTIC SCALE
CHANGE AS THE MID-LEVEL HIGH DRIFTS THROUGH NRN OHIO AND
STRENGTHENS SLIGHTLY WHILE THE LOW OVER THE WRN ATL ELONGATES SOME
BEGINS SPLITTING INTO TWO DISTINCT CYCLONIC CIRCULATION
CENTERS...ONE IN ERN GA AND THE OTHER OFF THE NC COAST.
VERY WEAK SFC FLOW WILL QUICKLY GO CALM THIS EVENING UNDER RAPIDLY
STRENGTHENING INVERSION AND DECOUPLING OF THE SHALLOWING BOUNDARY
LAYER. THIS SHOULD FOSTER A RAPID EVENING TEMP DROP WITH CLEAR
SKIES. RAN A GENERAL BLEND OF THE PREVIOUS FORECAST AND 12Z
ECMWF/GFS/NAM MOS...THOUGH TWEAKED A TOUCH DOWNWARD IN THE COOL
SPOTS GIVEN IDEAL RADIATIONAL COOLING REGIME. ALSO FOGGED UP THE
OHIO AND ADJACENT RIVER VALLEYS LATER IN THE NIGHT...AS BOUNDARY
LAYER MOISTURE FROM KY WILL BE SEEPING NWRD OVERNIGHT AS MINOR SLY
COMPONENT TO THE GENERAL EASTERLY FLOW WILL ALLOW AN INCREASE IN
LLVL MOISTURE. WOULD NOT BE SURPRISED IS FOG BECOMES A LITTLE MORE
WIDESPREAD THAN FORECAST ESP OVER NRN KY/SRN OH/SERN IND.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
VERY LITTLE CHANGE TO THE PATTERN ALOFT ON SATURDAY...THOUGH THE
LOW LEVELS WILL BEGIN TO UNDERGO SOME MOISTURE ADVECTION...ESPECIALLY
ACROSS SRN/SWRN FORECAST AREA. 18.12Z WRF/GFS INDICATE LOWEST 1KM
SPECIFIC HUMIDITIES DOUBLING IN COMPARISON TO FRIDAY...SO BROUGHT
DEWPOINTS UP A BIT IN THE SOUTH/SOUTHWEST...PERHAPS NOT ENOUGH.
FEEL 18.12Z NAM-WRF SFC DWPTS ABOUT 10F TOO HIGH AS HAS BEEN A
PROBLEM THIS SPRING...SO DISCOUNTING THE RATHER STRONG INSTBY THAT
DEVELOPS UNDERNEATH THE MID LEVEL RIDGE SATURDAY AFTERNOON. EVEN
SO...ADDITIONAL MOISTURE AND A FAVORABLE LAPSE RATE WILL NO DOUBT
YIELD SOME DEEPER CUMULUS ACROSS THE SOUTH/SOUTHWEST...BUT THINK
NIL FORCING AND CONTINUED RISING HEIGHTS WILL MITIGATE A NEED FOR
A RAIN CHANCE AT THIS TIME. A WARM DAY...AND MOS SHOULD PERFORM
WELL IN THIS RATHER PREDICTABLE REGIME...SO AGAIN BLENDED PREVIOUS
FORECAST WITH MOST RECENT VALUES. SPOT CHECK OF LOW LEVEL
THICKNESS CONSIDERATIONS AND MIXING TO 850-825MB /DESPITE VERY
WEAK FLOW/ SUGGESTS WIDESPREAD LOWER TO MIDDLE 80S...VERY MUCH IN
LINE WITH THE BLEND.
LIKELY A REPEAT SCENARIO SATURDAY NIGHT WITH VALLEY FOG...AND
LOWS IN THE 50S.
SUNDAY IS A CARBON-COPY OF SATURDAY. DISTINCT CIRCULATION CENTERS
ATTENDANT TO THE SOUTHEAST CONUS TROUGH RECOMBINE OVER THE OUTER
BANKS OF NC WHILE THE MID LEVEL ANTICYCLONE CONTINUES TO DEEPEN TO
585DM OVER INTERIOR NEW ENGLAND. THIS WILL REINFORCE A LOW LEVEL
EASTERLY TRAJECTORY...THUS DON/T EXPECT MUCH /IF ANY/ DEWPOINT
RISE ON SUNDAY...AND TEMPERATURES SHOULD HOLD VERY SIMILAR TO
SATURDAY/S READINGS. PROBABLY A THICKER CIRRUS SHIELD PER BUFR
SOUNDINGS...BUT THAT WOULD BE ABOUT THE EXTENT OF SENSIBLE
WEATHER.
SUNDAY NIGHT BEGINS TO SEE SOME CHANGE AS A TROUGH OF LOW PRESSURE
/DAMPENING OUT AND SLOWING AS IT ENCOUNTERS THE BLOCKY FLOW ALONG THE
EAST COAST/ APPROACHES THE GREAT LAKES. HAVE KEPT THE NIGHTTIME
DRY AT THIS POINT AS 18.12Z GUIDANCE WAFFLING ON WEAK/MID LEVEL-
BASED SHOWERS AND STORM PLACEMENT AS FORCING SLOWLY INCREASES
LATER IN THE NIGHT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
PERIOD OF DRY WEATHER MAY COME TO AN END MONDAY AS MOISTURE AND
INSTABILITY INCREASE AHEAD OF AN UPPER TROUGH. WITH THE ECMWF AND
GFS COMING INTO FAIR AGREEMENT...KEPT A CHANCE OF THUNDERSTORMS FOR
MONDAY...MAINLY IN WESTERN COUNTIES THAT WILL BE AFFECTED MORE BY
SURFACE CONVERGENCE AND COOLER AIR ALOFT.
STAYED CLOSE TO ECMWF SOLUTION FOR TUESDAY SINCE IT CONTINUES TO
SHOW A CLOSED UPPER LOW FORMING AS OPPOSED TO THE FASTER OPEN WAVE
DEPICTED ON THE GFS. AS THE UPPER LOW FORMS NEAR CVG...THERE WILL BE
A GOOD CHANCE FOR THUNDERSTORMS UNDER A COOL POOL ALOFT COUPLED WITH
DEEP MOISTURE ADVECTION FROM THE SOUTH.
THUNDERSTORMS CHANCES WILL DIMINISH ON WEDNESDAY AS THE CLOSED UPPER
LOW SLIPS EAST ALLOWING DRIER AND MORE STABLE AIR TO WORK IN. THE
DRY CONDITIONS ARE EXPECTED TO CONTINUE ON THURSDAY AND FRIDAY WHEN
RIDGING ALOFT IS FORECAST TO MOVE BACK IN.
HIGH TEMPERATURES WILL BE MAINLY IN THE 80S MONDAY ON THE EAST SIDE
OF THE UPPER TROUGH. COOLER READINGS IN THE 70S ARE FORECAST AS THE
CLOSED LOW MAKES ITS WAY ACROSS THE AREA WITH ASSOCIATED CLOUD COVER
AND COLD ADVECTION. LOOK FOR A REBOUND TO THE 80S BY FRIDAY AS
SUNSHINE AND WARM ADVECTION RETURN.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
HIGH PRESSURE WILL MAINTAIN CONTROL OF THE WEATHER THROUGH THE TAF
PERIOD. LOW LEVEL MOISTURE WILL BE INCREASING OVER THE NEXT DAY OR
SO...WHICH WILL ALLOW FOR SOME CUMULUS DEVELOPMENT TOMORROW.
OVERNIGHT TONIGHT...IT MAY ALLOW FOR SOME FOG TO DEVELOP AT THE
CINCINNATI TAF SITES (INCLUDING LIFR AT KLUK). WINDS WILL REMAIN
FAIRLY LIGHT THROUGH THE PERIOD...AND GENERALLY OUT OF THE ESE.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE MONDAY AND TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...BINAU
NEAR TERM...BINAU
SHORT TERM...BINAU
LONG TERM...CONIGLIO
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
122 AM EDT THU MAY 17 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE REGION PROVIDING DRY WEATHER
THROUGH THE REMAINDER OF THE WEEK. TEMPERATURES WILL GRADUALLY
WARM TO ABOVE NORMAL BY FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THE SURFACE COLD FRONT HAS JUST ABOUT CLEARED THE CWA...WITH ALL
SHOWER ACTIVITY NOW SOUTH OF THE BORDERING COUNTIES. ALTHOUGH
WINDS ARE OUT OF THE NORTHEAST AT ALL LOCATIONS...THE DEWPOINT
GRADIENT IS STILL LOCATED NEAR THE OHIO RIVER...WITH DEWPOINTS IN
THE MID 50S SOUTH OF THERE (AND MUCH DRIER CONDITIONS TO THE
NORTH).
ONLY MINOR ADJUSTMENTS WERE NECESSARY TO THE FORECAST...PRIMARILY
TO END POPS AND CLEAN UP THE SKY GRIDS TO REFLECT CURRENT
CONDITIONS. LOW TEMPERATURES APPEAR TO BE ON TRACK...AND SOME
READINGS BELOW 40 ARE POSSIBLE IN CENTRAL OHIO.
PREVIOUS DISCUSSION >
UPPER LEVEL TROF TO PIVOT EAST THRU THE GREAT LAKES INTO NEW
ENGLAND/SE CANADA BY THURSDAY MORNING. ASSOCIATED COLD FRONT WHICH
EXTENDS FROM WESTERN PA THRU SW OHIO AND SRN INDIANA TO DROP
SOUTH OF THE OHIO RIVER BY LATE AFTERNOON. BOTH NAM/GFS APPEAR
OVERDONE WITH SURFACE DEWPOINTS POOLED IN THE MID 60S ALONG AND
SOUTH OF THE FRONTAL BOUNDARY. 13 KM RAP MODEL SOLN LOOKS MORE
REALISTIC WITH DEWPOINTS IN THE UPPER 50S YIELDING MARGINAL BLYR
CAPES LESS THAN 1000 J/KG ACRS SE OHIO AND NRN KY. WL CONTINUE TO
LIMIT POPS TO SLIGHT CHANCE FOR THUNDERSTORMS ACRS THESE AREAS
EARLY. SINCE CONVECTION IS STARTING TO DEVELOP WILL OPT FOR AREAL
COVERAGE WORDING...ISOLATED THUNDERSTORMS.
IN THE WAKE OF THIS FRONT SFC HIGH PRESSURE BUILDS INTO THE GREAT
LAKES OVERNIGHT. SUBSIDENCE WILL LEAD TO CLEARING SKIES. DRY AIRMASS
AND LOW LEVEL CAA WILL LEAD TO BELOW NORMAL TEMPERATURES. HAVE FCST
LOWS RANGING FROM NEAR 40 NE TO LOWER 50S FAR SOUTH.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
SURFACE HIGH PRESSURE TO BUILD ACROSS THE GREAT LAKES ON THURSDAY.
DRY AIRMASS WILL RESULT IN MOSTLY SUNNY SKY CONDITIONS. EXPECT TEMPS
TO BE SLIGHTLY BELOW NORMAL. AFTER A COOL START TO THE DAY EXPECT
HIGHS TO RANGE FROM NEAR 70 NE TO THE MID 70S SW.
SURFACE HIGH PRESSURE TO SLIDE OFF TO THE EAST THURSDAY NIGHT.
EXPECT MAINLY CLEAR SKIES WITH ONLY SOME THIN HIGH LEVEL CLOUDS
SPILLING IN. HAVE FCST TEMPS RANGING FROM MID 40S NORTHEAST TO THE
LOWER 50S SOUTH.
MID/UPR LEVEL RIDGE TO BUILD INTO OHIO ON FRIDAY. EXPECT TO SEE A
GOOD DEAL OF SUNSHINE WITH JUST SOME HIGH LEVEL CLOUDINESS. UNDER
THE INFLUENCE OF WAA TEMPS WILL WARM TO VALUES ABOVE NORMAL. HAVE
FCST HIGHS FROM NEAR 80 NORTH TO THE LOWER 80S SOUTH.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
WITH AN UPPER RIDGE BUILDING OVERHEAD AND SURFACE HIGH PRESSURE
CENTERED TO THE EAST...A PERIOD OF DRY WEATHER IS INDICATED FOR
SATURDAY THROUGH MONDAY. CONFIDENCE IS RATHER HIGH FOR THIS TIME
FRAME DUE TO MODEL CONSISTENCY FROM RUN TO RUN.
AN UPPER LOW IS SHOWN TO DEVELOP OVER THE MISSISSIPPI VALLEY ON
TUESDAY...ACCOMPANIED BY INCREASING MOISTURE. THE LOW IS FORECAST TO
MOVE TO INDIANA ON WEDNESDAY. MODELS HAVE BEEN INCONSISTENT WITH THE
PATH OF THE UPPER LOW...MAKING THIS PART OF THE FORECAST LESS
CERTAIN. WENT WITH A CHANCE OF THUNDERSTORMS IN WESTERN COUNTIES ON
TUESDAY...EXPANDING TO THE WHOLE AREA ON WEDNESDAY.
WITH THE AREA IN A SOUTHERLY FLOW AND WITH CONSIDERABLE SUNSHINE TO
START...TEMPERATURES WILL BE ABOVE NORMAL THROUGH THE PERIOD. HIGHS
WILL BE MAINLY IN THE 80S SATURDAY THROUGH MONDAY...WITH INCREASING
CLOUDS AND POSSIBLE PRECIPITATION CAUSING READINGS TO SLIP TO THE
MID AND UPPER 70S BY WEDNESDAY.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE AND AN ASSOCIATED DRY AIRMASS WILL REMAIN IN PLACE
ACROSS THE REGION THROUGH TONIGHT. VFR CONDITIONS ARE EXPECTED
THROUGH THE TAF PERIOD.
OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...AR
NEAR TERM...HATZOS/AR
SHORT TERM...AR
LONG TERM...CONIGLIO
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS PORTLAND OR
928 PM PDT WED MAY 16 2012
.SYNOPSIS...ONSHORE FLOW WILL CONTINUE AS A WEAK UPPER LEVEL
TROUGH APPROACHES TONIGHT AND CROSSES THURSDAY. LOW CLOUDS WILL
SPREAD INLAND BY THURSDAY EVENING WITH PATCHY DRIZZLE POSSIBLE AS
THE UPPER TROUGH MOVES EAST THURSDAY NIGHT AND FRIDAY. MOST AREAS
WILL REMAIN DRY THROUGH THE WEEKEND. A RETURN TO WET WEATHER IS
LIKELY NEXT WEEK.
&&
.SHORT TERM...TONIGHT THROUGH SATURDAY...MINIMAL CLOUD COVER THIS
EVENING WITH HIGH CLOUDS REMAINING DOMINANT..ALBEIT THIN. SURFACE
DEWPOINTS CONTINUE TO DROP AS WELL BOTH INLAND AND TO A LESSER AMOUNT
AT THE COAST. AS SUCH...FEEL PREVIOUS THOUGHTS OF LOW CLOUDS
PROGRESSING INLAND MAY NOT MATERIALIZE. UPDATE WILL BE AVAILABLE
SHORTLY TO REDUCE CLOUD COVER FROM THE OVERNIGHT PERIOD AND EARLY
TOMORROW MORNING. AS AN UPPER TROUGH SLIDES ACROSS THE REGION
TOMORROW...EXPECT MARINE MOISTURE WILL STAND A BETTER CHANCE OF
STRENGTHENING AND PUSHING INLAND SO WILL LEAVE THE HIGHER CLOUD COVER
IN PLACE FOR TOMORROW AFTERNOON AND THEREAFTER. BY REMOVING
CLOUDS...HAVE ALSO DROPPED TEMPERATURES TONIGHT CLOSER TO WHAT WAS
SEEN LAST NIGHT OR EVEN A LITTLE COOLER.
EXTENSIVE LOW CLOUDS LOOK TO CONTINUE FRI MORNING AS ONSHORE FLOW
CONTINUES AND THE MARINE LAYER REMAINS DEEP...WITH SOME DRIZZLE OR
ISOLATED SHOWERS POSSIBLE OVER THE HIGHER TERRAIN. THE CLOUD COVER
AND COOLER AIR MASS WILL KEEP TEMPERATURES BELOW NORMAL LEVELS
THURSDAY AND FRIDAY.
HIGH PRESSURE WILL AGAIN BUILD INTO THE PACIFIC NORTHWEST SATURDAY
FOR A RETURN TO DRY SUNNY WEATHER WITH TEMPERATURES WARMING UP TO
NEAR 70 DEGREES. /JBONK
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...THE EXTENDED
FORECAST PERIOD BEGINS SATURDAY EVENING AS UPPER LEVEL RIDGING OVER
THE PACIFIC NORTHWEST IS ABOUT TO BREAK DOWN AND OPEN THE DOOR FOR
COOLER AND WETTER WEATHER AFTER SUNDAY. AN UPPER TROUGH APPROACHES
THE AREA...BRINGING A FRONT ONSHORE MONDAY. AS THE FRONT MOVES
THROUGH...THE JET STREAM DIPS SOUTH AND STRENGTHENS OVER THE EASTERN
PACIFIC. THIS DIRECTS A STORM TRACK AT THE NORTHWEST COAST THROUGH
ABOUT MIDWEEK. MODELS BEGIN TO DISAGREE AFTER MIDWEEK THOUGH AS THE
GFS AND THE GEM BUILD A RELATIVELY HIGH AMPLITUDE RIDGE OFFSHORE
WITH A TROUGH OVER THE WEST COAST. THE ECMWF LEANS TOWARD A MORE
ZONAL FLOW WITH POTENTIALLY WETTER WEATHER ON THE WAY. EITHER
WAY...IT APPEARS THAT THE SHORT BOUT OF SUNNY WEATHER MAY BE
TEMPORARILY ENDING. KELSON
&&
.AVIATION...MVFR STRATUS IS LINGERING NEAR THE COLUMBIA RIVER
MOUTH...WITH SOME PATCHY FOG FURTHER SOUTH ALONG THE IMMEDIATE
COASTLINE NEAR KONP. EXPECT IFR/MVFR STRATUS TO REDEVELOP ALONG
THE COAST OVERNIGHT BEFORE POSSIBLY SPREADING INLAND LATE
TONIGHT...PARTICULARLY ALONG THE COLUMBIA RIVER.
AT THIS TIME...MODELS INCLUDING THE RAP AND NAM CONTINUE TO SUGGEST
STRATUS SPREADING DOWN THE COLUMBIA RIVER. THE HI RESOLUTION RAPID
REFRESH MODELS DOES INDICATE SOME INLAND PENETRATION DOWN THE
RIVER...BUT NOT TO THE INLAND TAF SITES AND NOT THROUGH THE COASTAL
GAPS. THEREFORE CONFIDENCE AT THIS TIME IS LOW IN SEEING INLAND
STRATUS...AND WILL ELIMINATE THE BROKEN CEILING AND JUST LEAVE A
SCATTERED MENTION FOR NOW. THAT SAID...WE DO HAVE AN UPPER TROUGH
MOVING IN WHICH MAY ACT TO STRENGTHEN THE MARINE LAYER. IF IT DOES
DEVELOP ACROSS THE INTERIOR...IT SHOULD BURN OFF FAIRLY QUICKLY
THURSDAY. EXPECT A DIURNAL INCREASE IN NW WINDS LATE AFTERNOON AND
EARLY EVENING. KMD
&&
.MARINE...HIGH PRESSURE CENTERED NEAR 50 N/140W WILL WEAKEN SLOWLY
THE NEXT FEW DAYS AND MIGRATE CLOSER TO SHORE. MARGINAL SMALL CRAFT
ADVISORY LEVEL WINDS WILL CONTINUE MAINLY OVER THE OUTER WATERS WITH
ONSHORE NNW FLOW. WINDS PEAK IN THE AFTERNOON THURSDAY...BEFORE
EASING FRIDAY AS HIGH PRESSURE BECOMES CENTERED OVER THE COASTAL
WATERS. THIS WILL OPEN THE DOOR FOR A WEATHER PATTERN CHANGE...AND
ALLOW A FEW PACIFIC FRONTAL SYSTEMS TO MOVE INTO THE WATERS NEXT
WEEK.
THE PROLONGED NW WINDS STILL APPEAR LIKELY TO DRIVE SEAS UP TO NEAR
10 TO 11 FT BY THURSDAY ACROSS THE NORTHERN OUTER WATERS...BEFORE
SUBSIDING THURSDAY NIGHT. KMD
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM PDT THURSDAY FOR
WATERS FROM CAPE SHOALWATER WA TOFLORENCE OR FROM
10 TO 60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 5 AM TO 5 PM PDT
THURSDAY FOR WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD
OR FROM 10 TO 60 NM.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
229 PM EDT THU MAY 17 2012
.SYNOPSIS...
AN UPPER LEVEL LOW WILL FORM OVER SOUTH CAROLINA...AND WILL MOVE TO
THE NORTH CAROLINA COAST...WHERE IT WILL LINGER INTO EARLY NEXT
WEEK. HIGH PRESSURE WILL BUILD IN FROM THE NORTH AND REMAIN THROUGH
MONDAY. A COLD FRONT WILL APPROACH THE AREA FROM THE WEST ON
TUESDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
WATER VAPOR IMAGERY AND THE LATEST RAP MODEL RUN SHOW A NE TO SW
ORIENTED UPPER LOW STRETCHED OVER THE MIDLANDS OF SOUTH
CAROLINA...BACK ACROSS SOUTHEAST GEORGIA. A SPOKE OF PVA ON THE WEST
SIDE OF THE LOW IS HELPING TO ORGANIZE STRONG TO SEVERE CONVECTION
ACROSS THE SOUTHERN PART OF THE UPSTATE. ELSEWHERE...OTHER STORMS
WERE DEVELOPING OVER THE BLUE RIDGE OF NE GA AND SW NC. SOMEWHAT
DRIER AIR HAS PUSHED INTO THE NRN PIEDMONT AND FOOTHILLS OF NE...BUT
AREAS TO THE SOUTH REMAIN QUITE UNSTABLE WITH SB-CAPE VALUES RUNNING
FROM 1500-2000 J/JG. OUR LOCAL WORKSTATION WRF...THE NCEP 4KM WRF
AND THE HRRR ALL AGREE IN DEVELOPING CONVECTION OVER MUCH OF THE
UPSTATE...SOUTHERN NC MTNS AND FOOTHILLS AND NE GA INTO THE EVENING
HOURS. THIS WOULD BE SIMILAR TO WHAT HAPPENED LAST NIGHT. CONFIDENCE
IN THIS DEVELOPMENT IS FAIRLY HIGH...AND POPS WILL BE PUSHED UP TO
50 PERCENT ACROSS THE I-85 CORRIDOR AND UP INTO THE WRN NC FOOTHILLS
FOR THE EVENING HOURS. COOL MID-LEVEL TEMPS AND DRY AIR ALOFT WILL
CONTINUE TO SUPPORT SEVERE WIND AND HAIL EVENTS.
A BACK DOOR COLD FRONT WILL CROSS THE REGION LATE TONIGHT. THE NAM
MIXES DEWPOINTS INTO THE U40S TO L50S ACROSS THE NC FOOTHILLS AND
PIEDMONT AND THE ERN UPSTATE. THIS SHOULD FINALLY END THE THREAT OF
STORMS FOR THESE AREAS. BACK ACROSS THE MOUNTAINS...ESPECIALLY
CLOSER TO THE TN LINE...SCT CONVECTION SHOULD DEVELOP AGAIN TMRW
WHERE LLVL MOISTURE CONVERGENCE WILL BE MAXIMIZED.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AT 1430 EDT THURSDAY...A CLOSED UPPER LOW...PART OF AN EAST COAST
REX ...WILL BE LOCATED NEAR THE NC COAST ON FRIDAY NIGHT AND
SATURDAY. ON SUNDAY THIS FEATURE RETROGRADES SLIGHTLY INLAND. THE
MODELS SHOW DRIER AIR MOVING SW INTO OUR AREA ON THE BACK SIDE OF
THE LOW FRIDAY NIGHT AND SATURDAY....WHILE SOME MOISTURE LINGERS
ALONG THE BLUE RIDGE. ON SATURDAY NIGHT THE NAM SHOWS MOISTURE
SPREADING WEST ACROSS THE INTERSTATE 77 CORRIDOR TO THE NC BLUE
RIDGE...WHILE THE GFS REMAINS RATHER DRY UNTIL SUNDAY NIGHT.
POPS WILL INITIALLY BE QUITE LOW AND FOCUSED ALONG THE BLUE
RIDGE...THEN WILL INCREASE SLIGHTLY FROM THE EAST TOWARD SUNDAY...
BUT REMAINING RATHER LOW AS CONFIDENCE IS LIMITED ON THE AMOUNT AND
TIMING OF MOISTURE ENCROACHMENT FROM THE EAST. TEMPERATURES WILL
GENERALLY BE SLIGHTLY BELLOW NORMAL UNDER THE UPPER LOW HEIGHT
ANOMALY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AT 1430 EDT THURSDAY...A LONGWAVE TROUGH WILL PROGRESS ACROSS THE
EASTERN USA FROM MONDAY THROUGH WEDNESDAY...PROGRESSING OFFSHORE ON
THURSDAY WHEN A LONGWAVE RIDGE AXIS CROSSES THE MS RIVER VALLEY. A
CLOSED UPPER LOW WILL REMAIN NEAR THE CAROLINA COAST ON MONDAY. THIS
LOW FILLS AND DRIFTS NORTHEAST ON TUESDAY. A SHORTWAVE TROUGH DROPS
SOUTHEAST OVER THE SOUTHERN APPALACHIANS LATE TUESDAY...MOVING OFF
TO THE EAST ON WEDNESDAY.
SURFACE HIGH PRESSURE WILL BE OVER OUR ARE ON MONDAY...BETWEEN A
COASTAL LOW AND A COLD FRONT IN THE MS RIVER VALLEY. CONFIDENCE IS
LIMITED ON THE WESTERN EXTENT OF MOISTURE THAT WILL WRAP AROUND THE
COASTAL LOW TOWARD THE SOUTHERN APPALACHIANS...AND THE RESULTANT
POPS. THE COLD FRONT TO OUR WEST REACHES THE SOUTHERN APPALACHIANS
ON TUESDAY WHILE WEAKENING...WITH THE REMAINS OF THE BOUNDARY
SUPPORTING LENDING SUPPORT TO AT LEAST SMALL POPS. WEDNESDAY AND
THURSDAY FIND OUR AREA UNDER WEAK HIGH PRESSURE...BUT THE MODELS
DEPICT SOME AMOUNT OF LINGERING MOISTURE...OSTENSIBLY ASSOCIATED
WITH THE REMAINS OF THE FORMER FRONT. WITH GULF INFLOW EVENTUALLY
SETTING UP TO OUR WEST...SMALL POPS WILL BE MAINTAINED INTO
THURSDAY...ESPECIALLY IN THE WEST. TEMPERATURES WILL BE SLIGHTLY
ABOVE NORMAL IN MINOR HEIGHTS RISES BEHIND THE DEPARTING UPPER LOW.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
AT KCLT...STRONG THUNDERSTORMS WILL CONTINUE TO FIRE ABOUT 15 MILES
SOUTH OF THE AIRFIELD...THEN DRIFT SOUTH FROM THERE...OVER THE NEXT
COUPLE HOURS. HOWEVER...THE AIRMASS WILL BECOME MORE UNSTABLE BY
LATE AFTN. MOST OF THE SHORT RANGE MODELS WANT TO DEVELOP TSTMS
AROUND THE AIRFIELD STARTING IN A COUPLE HOURS AND THE NNE TO SSW
ORIENTED BANDS OF CU ACROSS THE REGION WILL LIKELY START TO DEEPEN
INTO CB/S WITH TIME. I/VE HELD ON TO VCSH TO ACCOUNT FOR THIS...BUT
A PERIOD OF TEMPO TSRA WILL PROBABLY NEED TO BE ADDED ONCE
DEVELOPMENT STARTS TO OCCUR FARTHER NORTH.
WINDS WILL REMAIN OUT OF THE NE THIS AFTN...THOUGH OUTFLOW BNDRYS
MAY PLAY HAVOC WITH THE WINDS AT TIMES. MVFR CIGS ARE EXPECTED AFTER
MIDNIGHT AS A BACK DOOR COLD FRONT SURGES THROUGH THE REGION. THE
CIGS ARE EXPECTED TO CLEAR OUT BEFORE SUNRISE HOWEVER.
ELSEWHERE...MUCH LIKE AT KCLT...THE ATMOSPHERE WILL BECOME MORE
UNSTABLE OVER THE UPSTATE...AND TSTMS WILL LIKELY BEGIN TO DEVELOP
ON OUTFLOW BNDRYS FROM STORMS EAST OF THE REGION NOW. THIS PROCESS
WILL TAKE A COUPLE HOURS. VCHS IS IN THE TAFS NOW...BUT A PERIOD OF
TEMPO GROUPS IS A GOOD BET ONCE THE NEW CELLS BEGIN TO FIRE.
CONFIDENCE IN TIMING JUST ISN/T HIGH ENUF TO TEMPO YET. KAVL IS MORE
STABLE...BUT SHRA MAY CONTINUE THERE FOR A GOOD BIT OF THE NIGHT.
WINDS OVER THE UPSTATE WILL GENERALLY BE OUT OF THE EAST THE REST OF
THE AFTN...TURNING NE LATE TONIGHT AS A BACK DOOR FRONT SURGES
THROUGH. A PERIOD OF MVFR CIGS IS EXPECTED TO ACCOMPANY THE FRONT.
OUTLOOK...EXPECT ISOLD LATE DAY SHOWERS AND TSTMS IN THE MTNS FRI
AFTN....THEN DRYING OVER THE WEEKEND. MRNG FOG WILL BE PSBL...ESP
MTN VALLEYS AND NEAR LAKES/RIVERS.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JAT
NEAR TERM...MCAVOY
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...MCAVOY
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
257 PM MDT THU MAY 17 2012
.DISCUSSION...
A BROAD...FLAT LONG WAVE TROF EXTENDS FROM COAST TO COAST THIS
MORNING WITH A SHORT WAVE TROF OVER CO. MODELS ARE IN GOOD
AGREEMENT IN BRINING A STRONGER TROF INLAND FROM THE PAC TO A
POSITION JUST W OF OUR CWA BY 12Z SAT. AIR MASS OVER THE AREA IS
CHARACTERIZED BY VERY STEEP LOW LEVEL LAPSE RATES AND LIMITED
MOISTURE. A FEW TSTMS HAVE DVLPD THIS AFTN MAINLY OVER THE HIER
TERRAIN OF THE BLACK HILLS WITH A FEW SHOWERS OVER NE WY AND NW SD.
GIVEN THE DRY LOW LVLS AND STEEP BELOW CLOUD LAPSE RATES THESE
STORMS COULD PRODUCE STRONG...GUSTY SFC WINDS DURING THE EVNG
HOURS. THE HRRR MODEL SHOWS A N TO S LINE OF TSTMS FROM NW SD
THROUGH RAP AND S WARD AT 03Z.
WITH THE APPROACH OF THE SECOND TROF FRIDAY AFTN THERE IS THE
CHANCE FOR MORE WIDESPREAD AND VIGOROUS CONVECTION. MOISTURE WILL
REAMIN LIMITED...BUT SFC BASED CAPE FCSTS OF ABT 1000 J/KG BY THE
18Z NAM LOOK REASONABLE. SFC TO 6KM SHEAR IS FCST TO RANGE FROM
ABOUT 40KTS OVER NW SD TO 20 KTS SE PORTIONS OF OUR CWA. A
BOUNDARY FROM TONIGHTS CONVECTION MAY PROVIDE SOME FOCUS AND WILL
BE REINFORCED BY INCREASING NRLY FLOW OVER WRN AND NWRN PORTIONS
OF THE CWA. NAM FCSTS THIS BOUNDARY TO BE FROM S OF RAP TO ROUGHLY
PHP AT 21Z FRIDAY.
WITH THE APPROACHING TROF...500 MB Q VECTOR CONVERGENCE REMAINS
OVER THE AREA FRIDAY NIGHT INTO SATURDAY EVG. POST FRONTAL SHOWERS
AND TSTMS SHOULD CONTINUE OVER MUCH THE AREA...GRADUALLY ENDING
FROM THE NW.
EXTENDED...AN UPPER RIDGE WILL BUILD INTO THE REGION EARLY NEXT WEEK
BRINGING DRY CONDITIONS. TEMPERATURES WILL BE NEAR AVERAGE
SUNDAY...WITH A GRADUAL WARMING TREND TO START THE WORK WEEK. MODELS
CONTINUE TO SHOW A SLOW MOVING UPPER TROUGH PUSHING INTO THE REGION
LATE TUESDAY INTO WEDNESDAY AND THURSDAY. MODELS CONSISTENCY IS
STILL LACKING (ECMWF CLOSES THE SYSTEM OFF WHILE GEM/GFS KEEP IT
OPEN)...BUT THIS COULD BRING A ROUND OF SHOWERS SHOWERS AND
THUNDERSTORMS TO THE AREA.
&&
.AVIATION...18Z TAFS
ISOLD/SCT TSRA AND SHRA WILL BE POSSIBLE THIS AFT AND EVE. VARIABLE
AND GUSTY WINDS ARE EXPECTED IN THE VICINITY OF ANY SHRA OR TSRA.
OTHERWISE...VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...BARBER
LONG TERM....77
AVIATION...77
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1218 PM CDT THU MAY 17 2012
.DISCUSSION.../ISSUED AT 1007 AM CDT/
NOT MUCH CHANGE TO CURRENT FORECAST. ACCAS SHOWERS NORTH OF WARM
FRONT HAS EXITED CWA WITH PARTLY TO MOSTLY SUNNY SKIES EXPECTED THIS
AFTERNOON. WINDS WILL BE GUSTY THIS AFTERNOON AND WILL BE CLOSE TO
WIND ADVISORY CRITERIA BUT WILL NOT ISSUE SINCE EVERYONE PRETTY MUCH
KNOWS IT IS WINDY. CURRENT TEMPERATURE FORECAST ON TRACK.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED TO REMAIN THROUGH 18Z FRIDAY. A STRONG LOW
LEVEL SOUTHERLY JET WILL PRODUCE LOW LEVEL WIND SHEAR AFTER 03Z
TONIGHT THROUGH 16Z FRIDAY. OTHERWISE...SURFACE WIND GUSTS TO 35
KNOTS CAN BE EXPECTED THROUGH 00Z TONIGHT AND DECREASE TO 15 TO 20
KNOTS 03Z TO 16Z FRIDAY AND THEN INCREASE TO 20 TO 35 KNOTS AGAIN
DURING THE DAY ON FRIDAY.
&&
.PREVIOUS DISCUSSION.../ISSUED AT 355 AM CDT/
WIDELY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS HAVE
DEVELOPED FROM JUST WEST OF SIOUX FALLS NORTHWARD ALONG THE
INTERSTATE 29 CORRIDOR OVERNIGHT UNDER THE INFLUENCE OF WARM
AIR/THETA E ADVECTION FACILITATED BY THE LOW LEVEL JET. ELEVATED
CONVECTION ALIGNS FAIRLY WELL WITH THE RUC 850-500MB OMEGA AND
INSTABILITY FIELDS...ALBEIT BOTH ARE RELATIVELY WEAK. THEREFORE
EXPECT THE ACTIVITY TO REMAIN ISOLATED IN NATURE. CONSIDERING WINDS
ARE HAULING AT 50-60 KTS AT TWO THOUSAND FEET...WILL NEED TO KEEP A
CLOSE EYE ON CELLS THAT DEVELOP AS THEY COULD BE WIND PRODUCERS. BY
DAYBREAK...ISOLATED ACTIVITY SHOULD BE MOSTLY CONFINED TO SW
MN...AND GRADUALLY WANE WITH LOSS OF THE LLJ INFLUENCE.
AFTER THE NOCTURNAL CONVECTION...THE NEXT ITEM OF FOCUS IS THE WIND
TODAY AND FRIDAY. 08Z SURFACE ANALYSIS ILLUSTRATED THE LOW
PRESSURE CENTER OVER WESTERN ND/SD. RELATIVELY TIGHT PRESSURE
GRADIENT AHEAD OF THIS FEATURE WILL SUPPORT WIND SPEEDS NEARING
ADVISORY CRITERIA /SUSTAINED 30 MPH/. NAM BUFKIT WINDS AT THE TOP OF
THE MIXED LAYER ARE CIRCA 40 KTS...BUT THERE WILL BE INCREASING
HIGH CLOUDS. WHILE ISOLATED LOCATIONS /ESPECIALLY HIGHER TERRAIN
AREAS/ COULD BRIEFLY HIT CRITERIA...DO NOT CURRENTLY EXPECTED
WIDESPREAD SUSTAINED SPEEDS AT 30 MPH. THEREFORE...WILL HOLD OFF
ON AN ADVISORY FOR NOW. TEMPERATURES WILL SOAR NEARLY 15 DEGREES
ABOVE NORMAL FOR THIS TIME OF YEAR...WITH HIGHS IN THE MID/UPPER
80S STILL APPEARING LIKELY.
LOWS TONIGHT WILL NOT DROP MUCH DUE TO THE PERSISTENT SOUTHERLY
FLOW AHEAD OF THE TROUGH. LOW TO MID 60S ARE EXPECTED TO BE COMMON
AT DAYBREAK FRIDAY. H85 TEMPERATURES CLIMB TO AROUND +22C ON
FRIDAY...WHICH SHOULD MAKE UPPER 80S AND LOWER 90S EASILY
ATTAINABLE.
THE COLD FRONT SHOULD REACH CENTRAL SD BY DAYBREAK SATURDAY...AND
TRACK EASTWARD ACROSS THE FORECAST AREA THROUGHOUT THE DAY. LIKELY
POPS SEEM WARRANTED ON SATURDAY AND SATURDAY NIGHT. INSTABILITY
AND SHEAR PARAMETERS ARE RATHER MARGINAL ON SATURDAY...SO SEVERE
THREAT STILL APPEARS TO BE FARTHER SOUTH. A FEW SHOWERS MAY LINGER
ON SUNDAY MAINLY EAST OF INTERSTATE 29...AND THEN RIDGING WILL
DEVELOP FOR THE START OF NEXT WEEK. AFTER TEMPERATURES ARE REDUCED
BACK INTO HE MID 60S TO LOWER 70S RANGE ON SUNDAY IN THE WAKE OF
THE FRONT...READINGS WILL GRADUALLY MODERATE TO VALUES IN THE
UPPER 70S AND LOWER 80S FOR TUESDAY.
SHOWER AND THUNDERSTORM CHANCES WILL RETURN FOR WEDNESDAY AND
THURSDAY...AS A RELATIVELY HEALTHY TROUGH TRACKS ACROSS THE NORTH
CENTRAL CONUS. HAVE INCLUDED 50-70 POPS FOR THIS SYSTEM.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR MNZ071-072-080-081-
090.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1007 AM CDT THU MAY 17 2012
.DISCUSSION.../ISSUED AT 1007 AM CDT/
NOT MUCH CHANGE TO CURRENT FORECAST. ACCAS SHOWERS NORTH OF WARM
FRONT HAS EXITED CWA WITH PARTLY TO MOSTLY SUNNY SKIES EXPECTED THIS
AFTERNOON. WINDS WILL BE GUSTY THIS AFTERNOON AND WILL BE CLOSE TO
WIND ADVISORY CRITERIA BUT WILL NOT ISSUE SINCE EVERYONE PRETTY MUCH
KNOWS IT IS WINDY. CURRENT TEMPERATURE FORECAST ON TRACK.
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED TO REMAIN THROUGH FRIDAY MORNING. A STRONG
LOW LEVEL JET WILL CONTINUE TO PRODUCE LOW LEVEL WIND SHEAR AT THE
TAF SITES EAST OF THE JAMES RIVER VALLEY THROUGH 18Z. THESE STRONGER
WINDS WILL BEGIN TO MIX OUT BY 15Z INCREASING THE SURFACE SPEEDS...
GUSTING UP TO 35 KTS DURING THE AFTERNOON MOST LOCATIONS. SURFACE
WIND GUSTS WILL DECREASE SOME OVERNIGHT THURSDAY NIGHT...THOUGH
WINDS WILL REMAIN STRONG ALOFT CREATING ADDITIONAL LOW LEVEL WIND
SHEAR FRIDAY MORNING.
&&
.PREVIOUS DISCUSSION.../ISSUED AT 355 AM CDT/
WIDELY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS HAVE
DEVELOPED FROM JUST WEST OF SIOUX FALLS NORTHWARD ALONG THE
INTERSTATE 29 CORRIDOR OVERNIGHT UNDER THE INFLUENCE OF WARM
AIR/THETA E ADVECTION FACILITATED BY THE LOW LEVEL JET. ELEVATED
CONVECTION ALIGNS FAIRLY WELL WITH THE RUC 850-500MB OMEGA AND
INSTABILITY FIELDS...ALBEIT BOTH ARE RELATIVELY WEAK. THEREFORE
EXPECT THE ACTIVITY TO REMAIN ISOLATED IN NATURE. CONSIDERING WINDS
ARE HAULING AT 50-60 KTS AT TWO THOUSAND FEET...WILL NEED TO KEEP A
CLOSE EYE ON CELLS THAT DEVELOP AS THEY COULD BE WIND PRODUCERS. BY
DAYBREAK...ISOLATED ACTIVITY SHOULD BE MOSTLY CONFINED TO SW
MN...AND GRADUALLY WANE WITH LOSS OF THE LLJ INFLUENCE.
AFTER THE NOCTURNAL CONVECTION...THE NEXT ITEM OF FOCUS IS THE WIND
TODAY AND FRIDAY. 08Z SURFACE ANALYSIS ILLUSTRATED THE LOW
PRESSURE CENTER OVER WESTERN ND/SD. RELATIVELY TIGHT PRESSURE
GRADIENT AHEAD OF THIS FEATURE WILL SUPPORT WIND SPEEDS NEARING
ADVISORY CRITERIA /SUSTAINED 30 MPH/. NAM BUFKIT WINDS AT THE TOP OF
THE MIXED LAYER ARE CIRCA 40 KTS...BUT THERE WILL BE INCREASING
HIGH CLOUDS. WHILE ISOLATED LOCATIONS /ESPECIALLY HIGHER TERRAIN
AREAS/ COULD BRIEFLY HIT CRITERIA...DO NOT CURRENTLY EXPECTED
WIDESPREAD SUSTAINED SPEEDS AT 30 MPH. THEREFORE...WILL HOLD OFF
ON AN ADVISORY FOR NOW. TEMPERATURES WILL SOAR NEARLY 15 DEGREES
ABOVE NORMAL FOR THIS TIME OF YEAR...WITH HIGHS IN THE MID/UPPER
80S STILL APPEARING LIKELY.
LOWS TONIGHT WILL NOT DROP MUCH DUE TO THE PERSISTENT SOUTHERLY
FLOW AHEAD OF THE TROUGH. LOW TO MID 60S ARE EXPECTED TO BE COMMON
AT DAYBREAK FRIDAY. H85 TEMPERATURES CLIMB TO AROUND +22C ON
FRIDAY...WHICH SHOULD MAKE UPPER 80S AND LOWER 90S EASILY
ATTAINABLE.
THE COLD FRONT SHOULD REACH CENTRAL SD BY DAYBREAK SATURDAY...AND
TRACK EASTWARD ACROSS THE FORECAST AREA THROUGHOUT THE DAY. LIKELY
POPS SEEM WARRANTED ON SATURDAY AND SATURDAY NIGHT. INSTABILITY
AND SHEAR PARAMETERS ARE RATHER MARGINAL ON SATURDAY...SO SEVERE
THREAT STILL APPEARS TO BE FARTHER SOUTH. A FEW SHOWERS MAY LINGER
ON SUNDAY MAINLY EAST OF INTERSTATE 29...AND THEN RIDGING WILL
DEVELOP FOR THE START OF NEXT WEEK. AFTER TEMPERATURES ARE REDUCED
BACK INTO HE MID 60S TO LOWER 70S RANGE ON SUNDAY IN THE WAKE OF
THE FRONT...READINGS WILL GRADUALLY MODERATE TO VALUES IN THE
UPPER 70S AND LOWER 80S FOR TUESDAY.
SHOWER AND THUNDERSTORM CHANCES WILL RETURN FOR WEDNESDAY AND
THURSDAY...AS A RELATIVELY HEALTHY TROUGH TRACKS ACROSS THE NORTH
CENTRAL CONUS. HAVE INCLUDED 50-70 POPS FOR THIS SYSTEM.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
357 AM CDT THU MAY 17 2012
.DISCUSSION.../ISSUED AT 355 AM CDT/
WIDELY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS HAVE
DEVELOPED FROM JUST WEST OF SIOUX FALLS NORTHWARD ALONG THE
INTERSTATE 29 CORRIDOR OVERNIGHT UNDER THE INFLUENCE OF WARM
AIR/THETA E ADVECTION FACILITATED BY THE LOW LEVEL JET. ELEVATED
CONVECTION ALIGNS FAIRLY WELL WITH THE RUC 850-500MB OMEGA AND
INSTABILITY FIELDS...ALBEIT BOTH ARE RELATIVELY WEAK. THEREFORE
EXPECT THE ACTIVITY TO REMAIN ISOLATED IN NATURE. CONSIDERING WINDS
ARE HAULING AT 50-60 KTS AT TWO THOUSAND FEET...WILL NEED TO KEEP A
CLOSE EYE ON CELLS THAT DEVELOP AS THEY COULD BE WIND PRODUCERS. BY
DAYBREAK...ISOLATED ACTIVITY SHOULD BE MOSTLY CONFINED TO SW
MN...AND GRADUALLY WANE WITH LOSS OF THE LLJ INFLUENCE.
AFTER THE NOCTURNAL CONVECTION...THE NEXT ITEM OF FOCUS IS THE WIND
TODAY AND FRIDAY. 08Z SURFACE ANALYSIS ILLUSTRATED THE LOW
PRESSURE CENTER OVER WESTERN ND/SD. RELATIVELY TIGHT PRESSURE
GRADIENT AHEAD OF THIS FEATURE WILL SUPPORT WIND SPEEDS NEARING
ADVISORY CRITERIA /SUSTAINED 30 MPH/. NAM BUFKIT WINDS AT THE TOP OF
THE MIXED LAYER ARE CIRCA 40 KTS...BUT THERE WILL BE INCREASING
HIGH CLOUDS. WHILE ISOLATED LOCATIONS /ESPECIALLY HIGHER TERRAIN
AREAS/ COULD BRIEFLY HIT CRITERIA...DO NOT CURRENTLY EXPECTED
WIDESPREAD SUSTAINED SPEEDS AT 30 MPH. THEREFORE...WILL HOLD OFF
ON AN ADVISORY FOR NOW. TEMPERATURES WILL SOAR NEARLY 15 DEGREES
ABOVE NORMAL FOR THIS TIME OF YEAR...WITH HIGHS IN THE MID/UPPER
80S STILL APPEARING LIKELY.
LOWS TONIGHT WILL NOT DROP MUCH DUE TO THE PERSISTENT SOUTHERLY
FLOW AHEAD OF THE TROUGH. LOW TO MID 60S ARE EXPECTED TO BE COMMON
AT DAYBREAK FRIDAY. H85 TEMPERATURES CLIMB TO AROUND +22C ON
FRIDAY...WHICH SHOULD MAKE UPPER 80S AND LOWER 90S EASILY
ATTAINABLE.
THE COLD FRONT SHOULD REACH CENTRAL SD BY DAYBREAK SATURDAY...AND
TRACK EASTWARD ACROSS THE FORECAST AREA THROUGHOUT THE DAY. LIKELY
POPS SEEM WARRANTED ON SATURDAY AND SATURDAY NIGHT. INSTABILITY
AND SHEAR PARAMETERS ARE RATHER MARGINAL ON SATURDAY...SO SEVERE
THREAT STILL APPEARS TO BE FARTHER SOUTH. A FEW SHOWERS MAY LINGER
ON SUNDAY MAINLY EAST OF INTERSTATE 29...AND THEN RIDGING WILL
DEVELOP FOR THE START OF NEXT WEEK. AFTER TEMPERATURES ARE REDUCED
BACK INTO HE MID 60S TO LOWER 70S RANGE ON SUNDAY IN THE WAKE OF
THE FRONT...READINGS WILL GRADUALLY MODERATE TO VALUES IN THE
UPPER 70S AND LOWER 80S FOR TUESDAY.
SHOWER AND THUNDERSTORM CHANCES WILL RETURN FOR WEDNESDAY AND
THURSDAY...AS A RELATIVELY HEALTHY TROUGH TRACKS ACROSS THE NORTH
CENTRAL CONUS. HAVE INCLUDED 50-70 POPS FOR THIS SYSTEM.
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED TO REMAIN THROUGH FRIDAY MORNING. A STRONG
LOW LEVEL JET WILL CONTINUE TO PRODUCE LOW LEVEL WIND SHEAR AT THE
TAF SITES EAST OF THE JAMES RIVER VALLEY THROUGH 18Z. THESE STRONGER
WINDS WILL BEGIN TO MIX OUT BY 15Z INCREASING THE SURFACE SPEEDS...
GUSTING UP TO 35 KTS DURING THE AFTERNOON MOST LOCATIONS. SURFACE
WIND GUSTS WILL DECREASE SOME OVERNIGHT THURSDAY NIGHT...THOUGH
WINDS WILL REMAIN STRONG ALOFT CREATING ADDITIONAL LOW LEVEL WIND
SHEAR FRIDAY MORNING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
940 PM CDT FRI MAY 18 2012
.UPDATE...
GRIDS IN EXCELLENT SHAPE. NO UPDATE NEEDED.
25
&&
.AVIATION...
ONLY CONCERNS ARE TRAJECTORY AND TIMING MVFR CIGS AFTER 09Z AND IF
ANY IMPACTS WILL BE SEEN AT WRN METRO AIRPORTS BY 12Z SATURDAY.
BOUNDARY LAYER RH PROGS ARE ALL SHOWING THAT MAIN TRAJECTORY OF
STRATUS WILL OCCUR ACROSS THE TX HILL COUNTRY INTO WEST-CENTRAL
TX JUST BEFORE 12Z SATURDAY. STRATUS WILL BE STRADDLING THE
I-35/I-35 W CORRIDOR PER LATEST SOUNDINGS INCLUDING RUC OPS40 AND
RH PROGS. SEE NO REASON TO REMOVE MVFR AT WACO AT THIS TIME...BUT
DO NOT HAVE ENOUGH CONFIDENCE TO ADD INTO METRO TERMINALS AT THIS
TIME AND WILL LEAVE VFR THROUGHOUT. WILL MONITOR SATELLITE AND OBS
CLOSELY THROUGH THE EVENING ON STRATUS TRENDS.
OTHERWISE...PREVAILING SOUTH FLOW 10-14 KTS TONIGHT WILL MIX LATER
SATURDAY MORNING WHICH WILL RESULT IN SOME GUSTS BY MIDDAY AT OR
ABOVE 25 KTS.
05/
&&
.PREV DISCUSSION... /ISSUED 326 PM CDT FRI MAY 18 2012/
LOW LEVEL WARM AIR ADVECTION WILL CONTINUE ACROSS THE REGION
TONIGHT THROUGH SUNDAY AS SURFACE LOW PRESSURE MOVES EASTWARD
FROM THE HIGH PLAINS. A RELATIVELY TIGHT PRESSURE GRADIENT WILL
RESULT IN BREEZY CONDITIONS THIS EVENING AND AGAIN ON SATURDAY.
AS THE SURFACE LOW MOVES EAST...SURFACE HIGH PRESSURE WILL BUILD
SOUTHWARD AND A COLD FRONT WILL APPROACH THE RED RIVER SUNDAY
MORNING. A FEW SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE COLD
FRONT...WITH THE BEST CHANCE OF STORMS NORTH OF THE RED RIVER.
THE FRONT SHOULD STALL DURING THE DAYTIME HOURS DUE TO VIGOROUS
MIXING ALONG THE LEADING EDGE...BUT WILL BEGIN TO MOVE SOUTH
AGAIN SUNDAY NIGHT/MONDAY. THE BEST PUSH BEHIND THE FRONT WILL BE
EAST OF THE REGION. THEREFORE...THE FRONT WILL MOST LIKELY STALL
ACROSS THE NORTHERN PORTIONS OF NORTH TEXAS MONDAY AFTERNOON. THE
ATMOSPHERE WILL BE UNSTABLE ENOUGH FOR SCATTERED SHOWERS AND
THUNDERSTORMS ALONG AND NORTH OF THE FRONT. SEVERE STORMS ARE
UNLIKELY DUE TO A WEAK SHEAR PROFILE. THE COLD FRONT WILL LIFT
QUICKLY NORTH OF THE REGION MONDAY NIGHT/TUESDAY AS THE UPPER
PATTERN BECOMES MORE ZONAL AND RESULTS IN A THE DEVELOPMENT OF A
LEE TROUGH. THIS PATTERN WILL KEEP NORTH TEXAS WARM AND HUMID
NEXT WEEK WITH HIGHS MAINLY IN THE UPPER 80S AND LOW 90S AND LOWS
GENERALLY IN THE 60S.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 65 87 65 86 65 / 0 5 5 10 10
WACO, TX 65 87 65 87 66 / 0 5 5 5 10
PARIS, TX 62 85 64 86 66 / 0 5 5 10 10
DENTON, TX 63 87 64 85 64 / 0 5 5 10 10
MCKINNEY, TX 61 87 64 86 65 / 0 5 5 10 10
DALLAS, TX 64 87 64 88 65 / 0 5 5 10 10
TERRELL, TX 63 88 63 86 64 / 0 5 5 10 10
CORSICANA, TX 64 88 65 87 67 / 0 5 5 5 10
TEMPLE, TX 64 86 64 86 65 / 0 5 5 5 10
MINERAL WELLS, TX 63 89 65 86 63 / 0 5 5 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/25
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
639 PM CDT FRI MAY 18 2012
.AVIATION...
ONLY CONCERNS ARE TRAJECTORY AND TIMING MVFR CIGS AFTER 09Z AND IF
ANY IMPACTS WILL BE SEEN AT WRN METRO AIRPORTS BY 12Z SATURDAY.
BOUNDARY LAYER RH PROGS ARE ALL SHOWING THAT MAIN TRAJECTORY OF
STRATUS WILL OCCUR ACROSS THE TX HILL COUNTRY INTO WEST-CENTRAL
TX JUST BEFORE 12Z SATURDAY. STRATUS WILL BE STRADDLING THE
I-35/I-35 W CORRIDOR PER LATEST SOUNDINGS INCLUDING RUC OPS40 AND
RH PROGS. SEE NO REASON TO REMOVE MVFR AT WACO AT THIS TIME...BUT
DO NOT HAVE ENOUGH CONFIDENCE TO ADD INTO METRO TERMINALS AT THIS
TIME AND WILL LEAVE VFR THROUGHOUT. WILL MONITOR SATELLITE AND OBS
CLOSELY THROUGH THE EVENING ON STRATUS TRENDS.
OTHERWISE...PREVAILING SOUTH FLOW 10-14 KTS TONIGHT WILL MIX LATER
SATURDAY MORNING WHICH WILL RESULT IN SOME GUSTS BY MIDDAY AT OR
ABOVE 25 KTS.
05/
&&
.PREV DISCUSSION... /ISSUED 326 PM CDT FRI MAY 18 2012/
LOW LEVEL WARM AIR ADVECTION WILL CONTINUE ACROSS THE REGION
TONIGHT THROUGH SUNDAY AS SURFACE LOW PRESSURE MOVES EASTWARD
FROM THE HIGH PLAINS. A RELATIVELY TIGHT PRESSURE GRADIENT WILL
RESULT IN BREEZY CONDITIONS THIS EVENING AND AGAIN ON SATURDAY.
AS THE SURFACE LOW MOVES EAST...SURFACE HIGH PRESSURE WILL BUILD
SOUTHWARD AND A COLD FRONT WILL APPROACH THE RED RIVER SUNDAY
MORNING. A FEW SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE COLD
FRONT...WITH THE BEST CHANCE OF STORMS NORTH OF THE RED RIVER.
THE FRONT SHOULD STALL DURING THE DAYTIME HOURS DUE TO VIGOROUS
MIXING ALONG THE LEADING EDGE...BUT WILL BEGIN TO MOVE SOUTH
AGAIN SUNDAY NIGHT/MONDAY. THE BEST PUSH BEHIND THE FRONT WILL BE
EAST OF THE REGION. THEREFORE...THE FRONT WILL MOST LIKELY STALL
ACROSS THE NORTHERN PORTIONS OF NORTH TEXAS MONDAY AFTERNOON. THE
ATMOSPHERE WILL BE UNSTABLE ENOUGH FOR SCATTERED SHOWERS AND
THUNDERSTORMS ALONG AND NORTH OF THE FRONT. SEVERE STORMS ARE
UNLIKELY DUE TO A WEAK SHEAR PROFILE. THE COLD FRONT WILL LIFT
QUICKLY NORTH OF THE REGION MONDAY NIGHT/TUESDAY AS THE UPPER
PATTERN BECOMES MORE ZONAL AND RESULTS IN A THE DEVELOPMENT OF A
LEE TROUGH. THIS PATTERN WILL KEEP NORTH TEXAS WARM AND HUMID
NEXT WEEK WITH HIGHS MAINLY IN THE UPPER 80S AND LOW 90S AND LOWS
GENERALLY IN THE 60S.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 65 87 65 86 65 / 0 5 5 10 10
WACO, TX 65 87 65 87 66 / 0 5 5 5 10
PARIS, TX 62 85 64 86 66 / 0 5 5 10 10
DENTON, TX 63 87 64 85 64 / 0 5 5 10 10
MCKINNEY, TX 61 87 64 86 65 / 0 5 5 10 10
DALLAS, TX 64 87 64 88 65 / 0 5 5 10 10
TERRELL, TX 63 88 63 86 64 / 0 5 5 10 10
CORSICANA, TX 64 88 65 87 67 / 0 5 5 5 10
TEMPLE, TX 64 86 64 86 65 / 0 5 5 5 10
MINERAL WELLS, TX 63 89 65 86 63 / 0 5 5 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1039 PM CDT FRI MAY 18 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SATURDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE
CENTERED OVER SOUTH DAKOTA AND A WARM FRONT LIFTING NE OVER LAKE
SUPERIOR. WITHIN THE WARM SECTOR...MOSTLY CLEAR SKIES EXIST ACROSS
THE FORECAST AREA WITH ONLY THIN CIRRUS DRIFTING OVERHEAD...AHEAD OF
A SHORTWAVE OVER THE PLAINS. DESPITE AWFULLY DRY AIR JUST ABOVE THE
SURFACE ON THE 12Z GRB RAOB...DEWPOINTS HAVE ACTUALLY BEEN
INCREASING THIS AFTERNOON AND HUMIDITY LEVELS HAVE BOTTOMED OUT IN
THE MID 20 PERCENT RANGE OVER CENTRAL WISCONSIN. WITH THE UPSTREAM
LOW PRESSURE BARELY REACHING THE MISSISSIPPI RIVER TOMORROW...TEMPS
AND HUMIDITIES ARE THE MAIN FORECAST CONCERNS.
TONIGHT...MID AND UPPER RIDGE AXIS WILL SLOWLY MOVE TO THE CENTRAL
GREAT LAKES TONIGHT...WHILE A WEAK SHORTWAVE OVER THE PLAINS MOVES
NE TO THE NORTHERN MISSISSIPPI VALLEY. VERY LITTLE THREAT OF PRECIP
WITH THIS WAVE DUE TO THE ABUNDANCE OF DRY AIR THROUGH THE
COLUMN...AND DO NOT EXPECT MORE THAN CIRRUS FLOATING OVERHEAD.
OTHERWISE...HIGH PRESSURE WILL SHIFT TO THE EAST COAST AND A COLD
FRONT WILL DRIFT ACROSS THE NORTHERN PLAINS. THE PRESSURE GRADIENT
WILL TIGHTEN A BIT TONIGHT WHICH WILL KEEP A SOUTHERLY BREEZE IN
PLACE. AS A RESULT...WILL SEE WARMER LOWS INTO THE MIDDLE AND UPPER
50S AT MOST LOCATIONS.
SATURDAY...THE UPSTREAM FRONT WILL MOVE INTO WESTERN WISCONSIN BY
LATE IN THE AFTERNOON. SOUTHERLY FLOW WILL STRENGTHEN A BIT BUT
WILL CONTINUE TO RECYCLE A DRY AIRMASS FROM THE DEPARTING HIGH
ACROSS THE STATE. SHOULD FEEL MORE HUMIDITY HOWEVER...AS THE DRY
AIRMASS MODIFIES AND MOISTURE GETS PULLED NORTHWARD AHEAD
OF THE FRONT. AFTER A WARMER START TO THE DAY...925MB TEMPS ARGUE
FOR HIGHS IN THE MIDDLE 80S AT MOST LOCATIONS INLAND FROM LAKE
MICHIGAN UNDER MOSTLY SUNNY CONDITIONS.
.LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY. SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH A SLOW MOVING COLD FRONT ARE THE
MAIN CONCERN FOR THE EARLY PART OF THIS FORECAST. THE ECMWF IS
STILL SLOWER THAN THE GFS BUT IS IT FASTER THAN YESTERDAY.
POTENTIAL FOR SEVERE WEATHER WILL LIKELY HINGE ON HOW WARM IT GETS
BEFORE CLOUDS ARRIVE. INSTABILITY APPEARS MODEST AND THERE ISN/T
MUCH DIRECTIONAL SHEAR. SO IT DOESN/T LOOK LIKE A BIG SEVERE
WEATHER DAY BUT WOULDN/T DOUBT ISOLATED STRONG OR SEVERE STORMS.
SHOWERS SHOULD END MONDAY AS FRONT EXITS THE REGION. THEN NICE
SEASONABLE WEATHER EXPECTED MONDAY NIGHT THROUGH THURSDAY WITH
SURFACE HIGH PRESSURE IN CONTROL.
BETTER GET THE AIR CONDITIONING WORKING IF THE ECMWF IS RIGHT
ABOUT NEXT SATURDAY AND SUNDAY. IT BUILDS A 591 DM UPPER RIDGE
OVER ILLINOIS. THIS WOULD BRING 90 DEGREE TEMPERATURES TO MUCH OF
OUR AREA WITH 60F DEW POINTS. THE GFS IS FURTHER EAST WITH THE
UPPER RIDGE SO WE MAY BE POSITIONED NEAR THE RING OF FIRE OF
CONVECTIVE COMPLEXES WHICH WOULD KEEP TEMPERATURES DOWN A BIT.
&&
.AVIATION...FOR 06Z TAF ISSUANCE. VFR CONDITIONS EXPECTED
THROUGHOUT. SITN OVERNIGHT IS MARGINAL FOR INCLUSION OF LLWS IN
THE TAFS...BUT WL CONT TO MENTION FOR WRN SITES. MODELS NOT
HANDLING MN CONVECTION WELL THIS EVENING...BUT WL COUNT ON DRY
SSELY FLOW HOLDING IT OFF TO THE WEST THROUGH TAF PERIOD.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1022 PM CDT FRI MAY 18 2012
.UPDATE...
CURRENT WATER VAPOR LOOPS AND 500 MB ANALYSIS SHOWS SHORT WAVE
THAT HELPED TRIGGER ONGOING THUNDERSTORMS IN MINNESOTA IS
DAMPENING OUT AS IT TRACKS NNE FROM NW IOWA INTO SW
MINNESOTA...WITH RIDGING PROTECTING SRN WI. NO CHANGES TO GOING FORECAST.
00Z/19 NAM STILL HOLDING PRECIPITATION OFF TO THE WEST WITH
STRONGER 850 MB FLOW AND BEST SURFACE TO 700 MB FRONTOGENETIC
FORCING ALONG AND JUST AHEAD OF SURFACE/MID LEVEL TROUGHS THROUGH
THE DAY SATURDAY. SOME HINT OF PCPN BRUSHING THE NW COUNTIES
OVERNIGHT SATURDAY NIGHT AS AXIS OF LOW-LEVEL JET BEGINS TO SHIFT
INTO WESTERN WISCONSIN.
&&
.AVIATION/06Z TAFS/...
VFR CONDITIONS FOR THE ENTIRE FORECAST PERIOD. ONLY CONCERN IS
POTENTIAL FOR LOW-LEVEL WIND SHEAR AS RAP AND LATEST NAM FORECAST
SOUNDINGS INDICATE WINDS BETWEEN 28 AND 32 KNOTS AROUND 1000-1200
FT AT TOP OF INVERSION. THIS DIFFERENTIAL JUST BELOW WIND SHEAR
CRITERIA...BUT WILL KEEP AN EYE ON PROFILER WINDS AND TAMDAR
REPORTS FOR ANY UPWARD TREND.
&&
.PREV DISCUSSION... /ISSUED 315 PM CDT FRI MAY 18 2012/
TONIGHT AND SATURDAY...FORECAST CONFIDENCE HIGH.
LOW PRESSURE TROUGH IN THE NORTHERN PLAINS WILL GRADUALLY SHIFT
EASTWARD THROUGH THE PERIOD. MEANWHILE...HIGH PRESSURE WILL REMAIN
PARKED OVER THE EASTERN UNITED STATES. THE INCREASING PRESSURE
GRADIENT ACROSS WISCONSIN WILL LEAD TO PERSISTENT SOUTHERLY WINDS
WITH WIND GUSTS IN THE 20 TO 25 KNOT RANGE ONCE AGAIN ON SATURDAY.
MIXING TO 850MB WILL ALLOW FOR LOW DEWPOINTS IN THE AFTERNOON AGAIN
AS WELL.
THE WARMEST TEMPS FOR THE WEEKEND ARE EXPECTED FOR SATURDAY. 925MB
TEMPS WILL INCREASE ABOUT 2 DEGREES FROM TODAY TO ABOUT 24C IN SOUTH
CENTRAL WI...YIELDING MAX TEMPS IN THE UPPER 80S. LOCATIONS NEAR THE
LAKE WILL REACH THEIR HIGHS IN THE LOWER 80S AROUND NOON...AND THEN
A LAKE BREEZE WILL DEVELOP AND DROP THE TEMPS THEREAFTER. MAX TEMPS
SHOULD BE IN THE UPPER 80S NORTH OF MILWAUKEE WITH AN EARLIER
SOUTHEAST WIND DEVELOPING.
ANY PRECIP ASSOCIATED WITH THE APPROACHING COLD FRONT WILL HOLD OFF
DURING THIS PERIOD. A FEW STREAMS OF HIGH CLOUDS WILL BE
OBSERVED...BUT OTHERWISE IT WILL JUST BE TOO DRY FOR DIURNAL CUMULUS
CLOUDS TO DEVELOP.
SATURDAY NIGHT THROUGH SUNDAY NIGHT..FORECAST CONFIDENCE IS MEDIUM.
A TROF OF LOW PRESSURE WILL BE OUT OVER THE CENTRAL PLAINS WITH
RIDGING TO THE EAST EARLY IN THIS PERIOD. THE WARM SECTOR WILL BE
FIRMLY IN PLACE SATURDAY NIGHT...SETTING THE STAGE FOR PRETTY MILD
OVERNIGHT READINGS. WILL CARRY A SLIGHT CHANCE OF A SHOWER OR
THUNDERSTORM OVER THE FAR WEST AFTER MIDNIGHT. THERE IS SOME WARM
AIR ADVECTION SHOWING UP AHEAD OF THE APPROACHING TROF ALONG WITH
A 35-40KT LOW LEVEL JET AND SOME UPPER LEVEL DIVERGENCE. THE
MODELS ALSO DEPICT SOME HIGHER LEVEL Q-VECTOR CONVERGENCE WITH A
WEAK SHORT WAVE RIDING UP HERE AHEAD OF THE MAIN TROF. JUST NOT
SURE WE HAVE ENOUGH MOISTURE TO SUPPORT ANYTHING.
THE FRONT WILL REACH THE WESTERN PORTION OF THE FORECAST AREA
DURING MID AFTERNOON ON SUNDAY. THE NAM AND ECMWF ARE IN THE BEST
AGREEMENT...WHILE THE GFS CONTINUES THE FASTER SOLUTION. SINCE THE
CANADIAN SOLUTIONS LOOK CLOSER TO THE NAM/ECMWF...WILL DISCARD THE
FAST GFS TIMING. SO FAIRLY QUIET YET SUNDAY MORNING...BUT EXPECT
SHOWERS AND STORMS TO BE INCREASING DURING THE AFTERNOON.
THUNDERSTORM PARAMETERS ARE NOT TOO IMPRESSIVE...SO NO SEVERE
WEATHER IS EXPECTED. THE DEEP LAYER SHEAR IS ON THE ORDER OF 15 TO
25KTS WITH CAPE VALUES PROBABLY IN THE 1500J/KG RANGE. LOOKS LIKE
PLENTY OF CLOUDINESS TO LIMIT DESTABILIZATION AS WELL. OUR IN
HOUSE AGGREGATED SEVERE WEATHER PARAMETER PRODUCT SHOWS A SOLID
DIMINISHING TREND WITH TIME FROM LATE MORNING THROUGH THE
AFTERNOON ON SUNDAY.
THE SURFACE TROF/COLD FRONT WILL BE SLOW TO EXIT AS THE ASSOCIATED
UPPER SYSTEM DIGS MORE INTO THE WESTERN GREAT LAKES...RATHER THAN
SCOOTING OFF TO THE EAST. THIS WILL KEEP PRECIP CHANCES IN THROUGH
SUNDAY NIGHT...AND MONDAY MORNING ACROSS THE EAST. THERE IS SOME
MODEL DISCREPANCY WITH HOW FAST THE PRECIP MIGHT EXIT.
MONDAY AND MONDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM.
COOLER TEMPERATURES WILL ARRIVE IN THE WAKE OF THE COLD FRONT.
HIGHS ON MONDAY SHOULD ONLY REACH THE MID TO UPPER 60S WITH A
NORTH WIND AND CLOUDY SKIES. A FEW FAVORED HOT SPOTS OUT WEST
COULD HIT 70. HIGH PRESSURE BUILDS IN AND WILL STICK AROUND FOR A
WHILE.
TUESDAY AND WEDNESDAY...FORECAST CONFIDENCE IS HIGH.
HIGH PRESSURE THIS PERIOD. QUIET WITH HIGHS IN THE 70S...WARMER
WEDNESDAY VS TUESDAY. COOLER BY THE LAKE WITH A SOUTHEAST BREEZE
SETTING UP AS THE HIGH IS EITHER OVERHEAD OR OFF TO OUR EAST.
THURSDAY AND BEYOND...FORECAST CONFIDENCE IS MEDIUM.
THE ECMWF HAS BEEN INDICATING A VERY HOT AND DRY END OF THE WEEK
NEXT WEEK. IT SHOWS A MASSIVE UPPER RIDGE BUILDING OVER THE
SOUTHEAST U.S. WITH SFC TEMPS POSSIBLY HITTING THE 90S FRIDAY AND
SATURDAY. THE GFS HAS HAD A MUCH COOLER AND WETTER SCENARIO WITH
HIGHS LIKELY ONLY IN THE 70S TO LOWER 80S. BUT...THE NEW 12Z GFS
IS STARTING TO COME IN LINE WITH THE ECMWF...WITH A BUILDING UPPER
RIDGE AND A DOMINANT SOUTHWEST UPPER LEVEL FLOW. IT NOW IS
SUGGESTING HIGHS IN THE 80S TO POSSIBLY 90 FOR AT LEAST THE START
OF THE MEMORIAL DAY WEEKEND...AND MAYBE BEYOND. THIS JUST ADDS
CONFIDENCE TO A WARM MEMORIAL DAY WEEKEND...BUT IT IS A LONG WAY
OFF YET. SO STAY TUNED.
AVIATION/00Z TAFS/...
VFR CONDITIONS WILL CONTINUE THROUGH SATURDAY...WITH ONLY SOME HIGH
CLOUDS EXPECTED IN THE AREA. CLEAR SKIES AND LIGHT SOUTH WINDS
TONIGHT. SOUTHERLY WINDS WILL BE IN THE 11 TO 15 KNOT RANGE WITH
GUSTS TO 21 KNOTS AGAIN ON SATURDAY WITH DEEP MIXING INTO DRY
AIR...ESPECIALLY INLAND. NEAR THE LAKE...LOOK FOR A LAKE BREEZE TO
DEVELOP BY EARLY AFTERNOON.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...REM
TONIGHT/SATURDAY AND AVIATION/MARINE...MRC
SATURDAY NIGHT THROUGH FRIDAY...DAVIS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
633 PM CDT FRI MAY 18 2012
.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
343 PM CDT FRI MAY 18 2012
AT 3 PM...A TIGHT SURFACE PRESSURE GRADIENT HAS DEVELOPED BETWEEN
A HIGH PRESSURE SYSTEM OVER NEW ENGLAND AND A LOW PRESSURE SYSTEM
OVER SOUTH DAKOTA. THIS GRADIENT WAS PRODUCING SUSTAINED WINDS IN
THE 15 TO 25 MPH RANGE AND WIND GUSTS AROUND 35 MPH. THE HIGHEST
WIND GUSTS WERE 37 MPH AT THE ROCHESTER ASOS AND NEAR DEXTER
MINNESOTA. THE COMBINATION OF SOUTHERLY WINDS AND ABUNDANT SUNSHINE
HAS ALLOWED TEMPERATURES TO CLIMB TO AROUND 90 ACROSS NORTHEAST
IOWA AND SOUTHEAST MINNESOTA...AND FROM THE MID TO LOWER 90S ACROSS
WESTERN WISCONSIN. THIS MAKES IT THE WARMEST DAY OF THIS YEAR IN
MOST LOCATIONS. SO FAR THIS AFTERNOON...THE WARMEST TEMPERATURE
REPORTED WAS 94 DEGREES FROM EYOTA /MINNESOTA DOT/.
FOR TONIGHT...THE 18.12Z MODELS ARE IN VERY GOOD AGREEMENT THAT
A POSITIVELY TILTED SHORT WAVE TROUGH WILL MOVE NORTHEAST THROUGH
THE REGION. BUFKIT SOUNDINGS SHOW THAT THE AIR MASS BELOW 600 MB
WILL REMAIN RATHER DRY. AS A RESULT...ONLY EXPECTING A SCATTERED
TO OCCASIONALLY BROKEN DECK OF MID AND HIGH CLOUDS TO MOVE THROUGH
THE REGION. THE GREATEST PERCENTAGE OF THESE CLOUDS WILL WEST OF
THE MISSISSIPPI RIVER.
ON SATURDAY...THE MAXIMUM TEMPERATURE FORECAST IS RATHER TRICKY.
THIS IS DUE TO THE UNCERTAINTY ON HOW WARM THE TEMPERATURES WILL
BE ALOFT /NAM HAS THE SAME TEMPERATURES AS TODAY AND THE GFS IS 2C
COOLER/ AND MORE AFTERNOON CLOUDS ACROSS THE REGION. DUE TO THE
LATTER...TRENDED THE FORECAST A COUPLE OF DEGREES COOLER.
THE GFS DOES GENERATE PRECIPITATION NORTH OF THE INTERSTATE 94
CORRIDOR ON SATURDAY AFTERNOON. THIS IS DUE TO A STRONG PV ANOMALY
MOVING NORTHEAST THROUGH THE REGION. MEANWHILE THE NAM/ECMWF/GEM
HAVE A MUCH WEAKER PV ANOMALY. SINCE THE GFS IS TYPICALLY TO
ROBUST WITH THESE ANOMALIES...SO OPTED TO KEEP THE FORECAST DRY.
ANOTHER FORECAST ISSUE ON SATURDAY AFTERNOON WILL BE THE DEW
POINTS. ALL OF THE MODELS ARE SHOWING THAT THE DEW POINTS WILL
CLIMB INTO THE LOWER 60S. THIS LOOKS TO BE TOO HIGH WHEN ONE
TAKES IN ACCOUNT THE DRY AIR ALOFT. THE DEW POINT MIX DOWN TOOL
SUGGESTS THAT THE DEW POINTS WILL BE MORE IN THE LOWER AND MID
50S. THIS SEEMS MUCH MORE REALISTIC...THUS...WENT AT LEAST 5 TO 8F
LOWER THAN THE MOS VALUES.
FROM SATURDAY NIGHT INTO SUNDAY...THE MODELS CONTINUE TO STRUGGLE
WITH THE TIMING OF THE COLD FRONT THROUGH THE REGION. THE GFS
CONTINUES TO THE FASTEST...AND IT HAS THE FRONT THROUGH THE ENTIRE
AREA BY EARLY AFTERNOON. MEANWHILE THE OTHER MODELS SUGGEST THAT
THIS WILL NOT OCCUR UNTIL SUNDAY EVENING. THE MAIN DIFFERENCE IS
HOW FAST THEY MOVE THE POSITIVELY TILTED SHORTWAVE TROUGH THE
REGION. WITH THE GFS BEING FASTER WITH THIS FEATURE...IT MAKES
SENSE THAT ITS FRONT WOULD MOVE THROUGH THE REGION FASTER. DUE TO
THIS WENT WITH MORE OF BLEND FOR THE WINDS...PRECIPITATION
CHANCES...AND TEMPERATURES. WITH ALL OF THE MODELS HINTING THAT
THE BEST MOISTURE TRANSPORT WOULD BE MAINLY NORTH AND NORTHWEST OF
THE FORECAST AREA...AS A RESULT TRENDED THE HIGHEST PRECIPITATION
CHANCES FOR THESE AREAS. WHILE ML CAPES CLIMB INTO THE 1500 TO
2500 J/KG...THE 0-6 KM BULK SHEAR IS LESS THAN 30 KNOTS...SO STILL
NOT THINKING THAT THERE WILL ANY SEVERE WEATHER FROM ANY OF THESE
STORMS.
.LONG TERM...MONDAY THROUGH FRIDAY
343 PM CDT FRI MAY 18 2012
THE 18.12Z MODELS ARE STARTING TO BECOME MORE IN AGREEMENT. THEY
SHOW THAT A COLD FRONT WILL SAG SOUTHWARD INTO THE AREA ON WEDNESDAY
NIGHT AND THEN LINGER ACROSS THE AREA THROUGH FRIDAY MORNING...AND
THEN MOVE NORTH AS A WARM FRONT ON FRIDAY AFTERNOON AND NIGHT.
THE LATTER IS ASSOCIATED WITH A RIDGE BUILDING ACROSS THE EASTERN
UNITED STATES. SINCE THE LATTER HAS BEEN VERY CONSISTENT IN THE
ECMWF...THERE WAS ENOUGH CONFIDENCE TO RAISE THE TEMPERATURES A
COUPLE OF DEGREES ABOVE THE CONSALL FOR LATE NEXT WEEK.
&&
.AVIATION...TONIGHT AND SATURDAY
633 PM CDT FRI MAY 18 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE ENTIRE TAF PERIOD...WITH
JUST SOME HIGH CIRRUS FROM TIME TO TIME. WINDS WILL DIMINISH THIS
EVENING BUT WILL STILL SEE SOME GUSTS AT KRST TO 20 TO 22 KNOTS
THROUGHOUT THE NIGHT. BIGGEST QUESTION IS LLWS POTENTIAL AT KLSE.
BOTH THE 18.18Z NAM AND 18.21Z RAP BUFKIT SOUNDINGS SHOWING WINDS
INCREASING TO NEAR 35 KNOTS AROUND 1500 FEET AFTER 06Z. DEPENDING
UPON HOW MUCH THE WINDS DECOUPLE IN THE VALLEY WILL DETERMINE LLWS
POTENTIAL. FOR NOW WILL LEAVE OUT AND JUST MONITOR WINDS THIS
EVENING. GREATEST POTENTIAL FOR LLWS WOULD BE 08Z-14Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
253 PM CDT FRI MAY 18 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1224 PM CDT THU MAY 17 2012
.SHORT TERM...
1022 AM CDT THU MAY 17 2012
MAIN FORECAST CONCERNS FOR THE AFTERNOON ARE WINDS AND DEWPOINTS.
15Z SURFACE ANALYSIS SHOWS LOW PRESSURE OVER THE DAKOTAS WITH A
PRESSURE FALL AREA OF NEAR 1 MB/HOUR OVER CENTRAL AND NORTHERN
MINNESOTA. THIS PRESSURE FALL AREA HAS BEEN TRANSLATING EASTWARD
THROUGH THE MORNING. THE PRESSURE GRADIENT HAS ALSO BEEN GRADUALLY
TIGHTENING THROUGH THE MORNING FROM WESTERN IOWA THROUGH MUCH OF
MINNESOTA. 12Z SOUNDING FROM MPX SHOWED A VERY DRY SOUNDING BELOW
650MB...BUT ALSO IMPORTANTLY 40 KT WINDS NEAR 950MB. A FEW SITES
THAT ARE ON THE HIGHER TERRAIN JUST SOUTH OF THE MINNESOTA RIVER
VALLEY HAVE BEEN EXPERIENCING WINDS OF 30 TO 40 MPH AND GUSTS NEAR
50 MPH. MEANWHILE...ALTOSTRATUS CLOUDS WITH BASES OF 9000 FT OR
HIGHER HAVE BEEN PUSHING EAST ACROSS MINNESOTA AND THE NORTH HALF OF
WISCONSIN...A RESULT OF ISENTROPIC LIFT IN THE WARM ADVECTION
PATTERN IN PLACE AHEAD OF THE LOW. IN ADDITION...ON WATER VAPOR A
SHORTWAVE TROUGH IS EVIDENT IN THE EASTERN DAKOTAS...LIKELY HELPING
OUT TOO TO PRODUCE THE CLOUDS. RADAR SHOWING SOME
PRECIPITATION...BUT MOST OF THIS HAS REMAINED AS VIRGA DUE TO THE
DRY SUB CLOUD AIR SEEN ON THAT MPX SOUNDING. KRST JUST REPORTED A
SPRINKLE...SO A LITTLE OF THIS VIRGA IS REACHING THE SURFACE.
REGARDING DEWPOINTS...THEY HAVE COME UP A LITTLE BIT DUE TO THE
NORMAL DIURNAL INCREASE...BUT THERE ARE LOWER ONES LURKING IN
SOUTHEAST IOWA (LOW TO MID 30S THERE).
WITH THE PRESSURE FALL AREA ANTICIPATED TO CONTINUE TRANSLATING
EASTWARD AND THE PRESSURE GRADIENT TIGHTENING...AND ALL OF THIS
HAPPENING DURING THE PEAK HEATING OF THE DAY...CONCERNED THAT
WINDS COULD TRY TO PUSH ADVISORY CRITERIA. CLOUDS RIGHT NOW OVER
MINNESOTA AND NORTHERN WISCONSIN ARE HOLDING MIXING DOWN
SOME...BUT THESE SHOULD DISSIPATE IN THE AFTERNOON AS THE
SHORTWAVE TROUGH WEAKENS AND PUSHES EAST...ALONG WITH THE
ISENTROPIC LIFT SHIFTING NORTH. 06Z MAV/00Z MET GUIDANCE BOTH
PUSH KRST AND KTOB TO AROUND 25 KT AT 21Z...WITH LATEST RAP
GUIDANCE SUGGESTING THE SAME THING. THESE SPEEDS ARE CLOSE TO
ADVISORY CRITERIA. AFTER COLLABORATION WITH MPX...DECIDED TO ERR
ON THE CAUTIOUS SIDE AND ISSUE THE ADVISORY FOR SOUTHEAST
MINNESOTA. TYPICALLY SOME OF NORTHEAST IOWA IS INCLUDED IN THESE
ADVISORY SITUATIONS TOO...BUT IT APPEARS RIGHT NOW THAT WINDS
ACROSS NORTHEAST IOWA WILL STAY BELOW ADVISORY CRITERIA.
REGARDING DEWPOINTS...WITH A PERSISTENT SOUTH FLOW...CONCERNED
THAT LOWER DEWPOINTS IN SOUTHEAST IOWA COULD ADVECT INTO THE
FORECAST AREA. CERTAINLY THE LACK OF RAIN LATELY WOULD SUPPORT
DEWPOINTS MIXING OUT...THOUGH WE HAVE GREENED UP. RAP RUNS HAVE
SUGGESTED DEWPOINTS DROPPING INTO THE 20S WITH SOUNDINGS THAT
SUGGEST LITTLE HELP FROM EVAPOTRANSPIRATION. MEANWHILE MOST OTHER
MODELS SUGGEST UPPER 30S TO LOW 40S AT BEST. FOR NOW HAVE
DISCOUNTED THE RAP RUNS...BUT LEANED TO THE LOW SIDE OF ALL OTHER
GUIDANCE. WILL BE INTERESTING TO SEE HOW LOW DEWPOINTS GET TODAY.
IF WE WERE NOT GREENED UP...TODAY WOULD BE CONCERNING FOR FIRE
WEATHER.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
315 AM CDT THU MAY 17 2012
17.00Z ECMWF/GFS STILL SHOWING DIFFERENCE IN TIMING OF THE COLD
FRONTAL PASSAGE ACROSS THE AREA/ASSOCIATED SHRA/TS CHANCES IN THE
SATURDAY NIGHT/SUNDAY TIME FRAME. THE GFS REMAINS THE FASTER OF
THE TWO MODELS WITH PASSAGE AROUND 18Z WHEREAS THE ECMWF HOLDS OFF
TIL EVENING. WITH THIS UNCERTAINTY...WILL KEEP MODEL CONSENSUS
APPROACH GOING FOR NOW. WITH SLOWER TIMING...THERE STANDS A CHANCE
FOR STRONG/SEVERE THUNDERSTORMS WITH AMPLE CAPE/BULK SHEAR
DEPICTED BY THE ECMWF. HOPEFULLY THE MODELS WILL HAVE THIS
RESOLVED A BIT BETTER WITHIN THE NEXT FEW RUNS. MODELS THEN KEEP
DIFFERENCES GOING THROUGH THE REMAINDER OF THE PERIOD WITH THE GFS
MAINTAINING A MORE PROGRESSIVE WAVE PATTERN COMPARED TO THE ECMWF.
ECMWF KEEPS TROUGH/COOLER CYCLONIC FLOW AROUND THE AREA SUNDAY
NIGHT THROUGH TUESDAY FOR A SMALL CHANCE OF SHOWERS/ISOLATED
THUNDER. THE GFS BRINGS RIDGING IN FAIRLY QUICK FOR A DRIER
SOLUTION. WILL KEEP MODEL CONSENSUS GOING HERE AS WELL DUE TO THE
UNCERTAINTY. UPPER/SURFACE FLOW BECOMES SOUTHERLY ON WEDNESDAY
WITH BOTH MODELS SHOWING A WEAK EMBEDDED WAVE ALOFT. THE ECMWF
SHOWS LIGHT QPF SIGNAL WITH THIS FEATURE WHILE THE GFS REMAINS
DRY. WILL INCLUDE A SLIGHT CHANCE OF SHOWERS/THUNDER FOR NOW.
OTHERWISE...LOOKS LIKE TEMPERATURES WILL START OFF SOME 10 DEGREES
ABOVE NORMAL ON SUNDAY IN THE MID 70-LOWER 80S...THEN NEAR NORMAL
IN THE 70S MON/TUE/WED.
&&
.AVIATION...THROUGH 18Z FRIDAY
1224 PM CDT THU MAY 17 2012
A PERSISTENT SOUTHERLY FLOW OF DRY AIR WILL HELP TO MAINTAIN VFR
CONDITIONS THROUGH THE FRIDAY. THE BIGGER ISSUE IS WINDS. A TIGHT
PRESSURE GRADIENT IN PLACE AHEAD OF LOW PRESSURE IN THE DAKOTAS
HAS ALREADY RESULTED IN GUSTS BETWEEN 20-30 KT AT BOTH TAF SITES.
LOOK FOR THE GUSTS AS WELL AS SUSTAINED SPEEDS TO INCREASE A
LITTLE MORE THIS AFTERNOON WITH DAYTIME HEATING. WINDS SHOULD COME
DOWN SOME THIS EVENING WITH LOSS OF HEATING...BUT A STRONG LOW
LEVEL JET COMING ACROSS TONIGHT SHOULD KEEP KRST GUSTY THROUGH
MUCH OF THE NIGHT. WITH KLSE IN THE VALLEY...FAVORING LIGHTER
WINDS AT THE SURFACE...HAVE INCLUDED LOW LEVEL WIND SHEAR FOR THE
LOW LEVEL JET. PLAN ON SOUTHERLY WINDS TO PICK BACK UP FRIDAY
MORNING WITHIN A FEW HOURS OF SUNRISE DUE TO MIXING. WINDS ON
FRIDAY DO NOT LOOK AS STRONG AS TODAY...DUE TO A WEAKER PRESSURE
GRADIENT FORECAST...BUT SUSTAINED SPEEDS OF 15 KT WITH GUSTS TO
25 KT OR SO LOOK LIKELY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
1022 AM CDT THU MAY 17 2012
WI...NONE.
MN...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM CDT THIS EVENING
FOR MNZ079-086-087-094-095.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...DAS
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1022 AM CDT THU MAY 17 2012
.SHORT TERM...
1022 AM CDT THU MAY 17 2012
MAIN FORECAST CONCERNS FOR THE AFTERNOON ARE WINDS AND DEWPOINTS.
15Z SURFACE ANALYSIS SHOWS LOW PRESSURE OVER THE DAKOTAS WITH A
PRESSURE FALL AREA OF NEAR 1 MB/HOUR OVER CENTRAL AND NORTHERN
MINNESOTA. THIS PRESSURE FALL AREA HAS BEEN TRANSLATING EASTWARD
THROUGH THE MORNING. THE PRESSURE GRADIENT HAS ALSO BEEN GRADUALLY
TIGHTENING THROUGH THE MORNING FROM WESTERN IOWA THROUGH MUCH OF
MINNESOTA. 12Z SOUNDING FROM MPX SHOWED A VERY DRY SOUNDING BELOW
650MB...BUT ALSO IMPORTANTLY 40 KT WINDS NEAR 950MB. A FEW SITES
THAT ARE ON THE HIGHER TERRAIN JUST SOUTH OF THE MINNESOTA RIVER
VALLEY HAVE BEEN EXPERIENCING WINDS OF 30 TO 40 MPH AND GUSTS NEAR
50 MPH. MEANWHILE...ALTOSTRATUS CLOUDS WITH BASES OF 9000 FT OR
HIGHER HAVE BEEN PUSHING EAST ACROSS MINNESOTA AND THE NORTH HALF OF
WISCONSIN...A RESULT OF ISENTROPIC LIFT IN THE WARM ADVECTION
PATTERN IN PLACE AHEAD OF THE LOW. IN ADDITION...ON WATER VAPOR A
SHORTWAVE TROUGH IS EVIDENT IN THE EASTERN DAKOTAS...LIKELY HELPING
OUT TOO TO PRODUCE THE CLOUDS. RADAR SHOWING SOME
PRECIPITATION...BUT MOST OF THIS HAS REMAINED AS VIRGA DUE TO THE
DRY SUB CLOUD AIR SEEN ON THAT MPX SOUNDING. KRST JUST REPORTED A
SPRINKLE...SO A LITTLE OF THIS VIRGA IS REACHING THE SURFACE.
REGARDING DEWPOINTS...THEY HAVE COME UP A LITTLE BIT DUE TO THE
NORMAL DIURNAL INCREASE...BUT THERE ARE LOWER ONES LURKING IN
SOUTHEAST IOWA (LOW TO MID 30S THERE).
WITH THE PRESSURE FALL AREA ANTICIPATED TO CONTINUE TRANSLATING
EASTWARD AND THE PRESSURE GRADIENT TIGHTENING...AND ALL OF THIS
HAPPENING DURING THE PEAK HEATING OF THE DAY...CONCERNED THAT
WINDS COULD TRY TO PUSH ADVISORY CRITERIA. CLOUDS RIGHT NOW OVER
MINNESOTA AND NORTHERN WISCONSIN ARE HOLDING MIXING DOWN
SOME...BUT THESE SHOULD DISSIPATE IN THE AFTERNOON AS THE
SHORTWAVE TROUGH WEAKENS AND PUSHES EAST...ALONG WITH THE
ISENTROPIC LIFT SHIFTING NORTH. 06Z MAV/00Z MET GUIDANCE BOTH
PUSH KRST AND KTOB TO AROUND 25 KT AT 21Z...WITH LATEST RAP
GUIDANCE SUGGESTING THE SAME THING. THESE SPEEDS ARE CLOSE TO
ADVISORY CRITERIA. AFTER COLLABORATION WITH MPX...DECIDED TO ERR
ON THE CAUTIOUS SIDE AND ISSUE THE ADVISORY FOR SOUTHEAST
MINNESOTA. TYPICALLY SOME OF NORTHEAST IOWA IS INCLUDED IN THESE
ADVISORY SITUATIONS TOO...BUT IT APPEARS RIGHT NOW THAT WINDS
ACROSS NORTHEAST IOWA WILL STAY BELOW ADVISORY CRITERIA.
REGARDING DEWPOINTS...WITH A PERSISTENT SOUTH FLOW...CONCERNED
THAT LOWER DEWPOINTS IN SOUTHEAST IOWA COULD ADVECT INTO THE
FORECAST AREA. CERTAINLY THE LACK OF RAIN LATELY WOULD SUPPORT
DEWPOINTS MIXING OUT...THOUGH WE HAVE GREENED UP. RAP RUNS HAVE
SUGGESTED DEWPOINTS DROPPING INTO THE 20S WITH SOUNDINGS THAT
SUGGEST LITTLE HELP FROM EVAPOTRANSPIRATION. MEANWHILE MOST OTHER
MODELS SUGGEST UPPER 30S TO LOW 40S AT BEST. FOR NOW HAVE
DISCOUNTED THE RAP RUNS...BUT LEANED TO THE LOW SIDE OF ALL OTHER
GUIDANCE. WILL BE INTERESTING TO SEE HOW LOW DEWPOINTS GET TODAY.
IF WE WERE NOT GREENED UP...TODAY WOULD BE CONCERNING FOR FIRE
WEATHER.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
315 AM CDT THU MAY 17 2012
17.00Z ECMWF/GFS STILL SHOWING DIFFERENCE IN TIMING OF THE COLD
FRONTAL PASSAGE ACROSS THE AREA/ASSOCIATED SHRA/TS CHANCES IN THE
SATURDAY NIGHT/SUNDAY TIME FRAME. THE GFS REMAINS THE FASTER OF
THE TWO MODELS WITH PASSAGE AROUND 18Z WHEREAS THE ECMWF HOLDS OFF
TIL EVENING. WITH THIS UNCERTAINTY...WILL KEEP MODEL CONSENSUS
APPROACH GOING FOR NOW. WITH SLOWER TIMING...THERE STANDS A CHANCE
FOR STRONG/SEVERE THUNDERSTORMS WITH AMPLE CAPE/BULK SHEAR
DEPICTED BY THE ECMWF. HOPEFULLY THE MODELS WILL HAVE THIS
RESOLVED A BIT BETTER WITHIN THE NEXT FEW RUNS. MODELS THEN KEEP
DIFFERENCES GOING THROUGH THE REMAINDER OF THE PERIOD WITH THE GFS
MAINTAINING A MORE PROGRESSIVE WAVE PATTERN COMPARED TO THE ECMWF.
ECMWF KEEPS TROUGH/COOLER CYCLONIC FLOW AROUND THE AREA SUNDAY
NIGHT THROUGH TUESDAY FOR A SMALL CHANCE OF SHOWERS/ISOLATED
THUNDER. THE GFS BRINGS RIDGING IN FAIRLY QUICK FOR A DRIER
SOLUTION. WILL KEEP MODEL CONSENSUS GOING HERE AS WELL DUE TO THE
UNCERTAINTY. UPPER/SURFACE FLOW BECOMES SOUTHERLY ON WEDNESDAY
WITH BOTH MODELS SHOWING A WEAK EMBEDDED WAVE ALOFT. THE ECMWF
SHOWS LIGHT QPF SIGNAL WITH THIS FEATURE WHILE THE GFS REMAINS
DRY. WILL INCLUDE A SLIGHT CHANCE OF SHOWERS/THUNDER FOR NOW.
OTHERWISE...LOOKS LIKE TEMPERATURES WILL START OFF SOME 10 DEGREES
ABOVE NORMAL ON SUNDAY IN THE MID 70-LOWER 80S...THEN NEAR NORMAL
IN THE 70S MON/TUE/WED.
&&
.AVIATION...TODAY AND TONIGHT
618 AM CDT THU MAY 17 2012
BREEZY VFR CONDITIONS EXPECTED THROUGH THE PERIOD. AS A STORM
SYSTEM DEVELOPS OVER SOUTH DAKOTA TODAY...THE GRADIENT WILL
TIGHTEN OVER THE REGION. THIS WILL PRODUCE SOUTH WINDS AT BOTH TAF
SITES WITH SUSTAINED SPEEDS AROUND 20 KNOTS. GUSTS WILL DEVELOP BY
MID TO LATE MORNING AND CONTINUE INTO THE EARLY EVENING. KLSE
SHOULD GUST TO AROUND 25 KNOTS WITH GUSTS TO AROUND 30 KNOTS
EXPECTED AT KRST. THE GUSTS SHOULD DIMINISH BY EARLY EVENING BUT
LOOK FOR SUSTAINED SPEEDS TO REMAIN BETWEEN 10 AND 15 KNOTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
1022 AM CDT THU MAY 17 2012
WI...NONE.
MN...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM CDT THIS EVENING
FOR MNZ079-086-087-094-095.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
618 AM CDT THU MAY 17 2012
.SHORT TERM...TONIGHT THROUGH SATURDAY
315 AM CDT THU MAY 17 2012
FORECAST CONCERNS INCLUDE SHRA CHANCES ACROSS THE NORTH TODAY AND
THEN INCREASING WARMTH THROUGH THE REMAINDER OF THE PERIOD.
LATEST WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW RIDGING OVER THE
IMMEDIATE FORECAST AREA WITH A WEAK MID-LEVEL TROUGH OVER THE
NORTHERN PLAINS. SURFACE ANALYSIS AT 3 AM HAS HIGH PRESSURE OVER THE
GREAT LAKES REGION WITH AN AREA OF LOW PRESSURE OVER THE NORTHERN
PLAINS. A WARM FRONT EXTENDED FROM THIS LOW EAST-SOUTHEASTWARD
ACROSS SOUTHERN MN INTO NORTHEAST IA. MOISTURE TRANSPORT/ISENTROPIC
LIFT AHEAD OF THE LOW AND OVER THE WARM FRONT WAS PRODUCING SOME
VERY HIGH-BASED SHRA/ISOLATED THUNDER ACROSS CENTRAL SD INTO FAR
SOUTHWEST MN.
17.00Z NCEP MODELS/17.21Z SREF IN GOOD AGREEMENT WITH OVERALL
SYNOPTIC SETUP THROUGH THE PERIOD.
FOR TODAY...LOW PRESSURE WILL STAY PUT ACROSS THE NORTHERN PLAINS AS
THE WARM FRONT LIFTS NORTH INTO CENTRAL MN/NORTHERN WI BY EARLY THIS
EVENING. AXIS OF LIGHT TO MODERATE 925-850MB MOISTURE TRANSPORT
STAYS NORTH OF THE AREA WITH BULK FAIRLY STRONG ISENTROPIC LIFT
FOLLOWING SUIT. EITHER WAY...LOWEST 700-600MB VERY DRY AS EVIDENCED
BY THE 17.00Z MPX SOUNDING AND NAM BUFKIT SOUNDINGS. MOST SHRA
ACTIVITY WILL BE FALLING OUT OF ACCAS CLOUD AT OR ABOVE 10-12KFT.
WOULD TAKE VIGOROUS CONVECTION FOR ANYTHING TO REACH THE GROUND. AS
SUCH...HAVE TRIMMED POPS FARTHER NORTH AND KEPT A SMALL CHANCE OF
SHRA/ISOLD THUNDER CONFINED NORTH OF HIGHWAY 10 IN WISCONSIN.
OTHERWISE...LOOK FOR INCREASING SOUTH WINDS TODAY WITH INCREASING
PRESSURE GRADIENT. WINDS ACROSS MUCH OF THE AREA SHOULD BE IN THE
15-25 MPH RANGE...BUT THE HIGHER/MORE WIND-PRONE AREAS OF SOUTHEAST
MN/NORTHEAST IA WILL LIKELY SEE WINDS MORE IN THE 20-25 MPH RANGE
WITH GUSTS AROUND 35 MPH. WITH WARM ADVECTION/RISING MOTIONS IN THE
BOUNDARY LAYER MITIGATING DOWNWARD TRANSFER OF STRONGER WINDS
ALOFT...FEEL WINDS WILL BE JUST SHY OF WIND ADVISORY. WILL HAVE TO
KEEP A CLOSE EYE ON THIS. TEMPERATURES ARE EXPECTED TO RESPOND TO
INCREASING SOUTHERLY FLOW WITH AFTERNOON HIGHS TOPPING OFF IN THE
UPPER 60S ACROSS NORTHERN WISCONSIN...TO THE MID-UPPER 70S
ELSEWHERE.
WARM FRONT PUSHES NORTH OF THE AREA THIS EVENING WITH A STRONG CAP
SETTING UP ACROSS THE AREA IN THE WARM SECTOR ON FRIDAY. WITH MOSTLY
SUNNY SKIES AND STRONG SOUTHERLY FLOW...TEMPERATURES SHOULD HAVE NO
PROBLEM REACHING INTO THE UPPER 70S TO MIDDLE 80S. DEW POINTS WILL
ALSO BE ON THE RISE INTO THE 50S FOR A SLIGHTLY MORE MUGGY FEEL
COMPARED TO THE LAST FEW DAYS.
COLD FRONT AND ASSOCIATED CONVECTION OVER THE NORTHERN PLAINS MAKES A MOVE
EASTWARD INTO MN/WESTERN IA ON SATURDAY WITH CAP HOLDING FIRM ACROSS
OUR FORECAST AREA. CONTINUED STRONG SOUTHERLY FLOW AND PARTLY TO
MOSTLY SUNNY SKIES SHOULD PUSH TEMPERATURES INTO THE MID-UPPER 80S.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
315 AM CDT THU MAY 17 2012
17.00Z ECMWF/GFS STILL SHOWING DIFFERENCE IN TIMING OF THE COLD
FRONTAL PASSAGE ACROSS THE AREA/ASSOCIATED SHRA/TS CHANCES IN THE SATURDAY
NIGHT/SUNDAY TIME FRAME. THE GFS REMAINS THE FASTER OF THE TWO
MODELS WITH PASSAGE AROUND 18Z WHEREAS THE ECMWF HOLDS OFF TIL
EVENING. WITH THIS UNCERTAINTY...WILL KEEP MODEL CONSENSUS APPROACH
GOING FOR NOW. WITH SLOWER TIMING...THERE STANDS A CHANCE FOR
STRONG/SEVERE THUNDERSTORMS WITH AMPLE CAPE/BULK SHEAR DEPICTED BY
THE ECMWF. HOPEFULLY THE MODELS WILL HAVE THIS RESOLVED A BIT BETTER
WITHIN THE NEXT FEW RUNS. MODELS THEN KEEP DIFFERENCES GOING THROUGH
THE REMAINDER OF THE PERIOD WITH THE GFS MAINTAINING A MORE
PROGRESSIVE WAVE PATTERN COMPARED TO THE ECMWF. ECMWF KEEPS
TROUGH/COOLER CYCLONIC FLOW AROUND THE AREA SUNDAY NIGHT THROUGH
TUESDAY FOR A SMALL CHANCE OF SHOWERS/ISOLATED THUNDER. THE GFS
BRINGS RIDGING IN FAIRLY QUICK FOR A DRIER SOLUTION. WILL KEEP MODEL
CONSENSUS GOING HERE AS WELL DUE TO THE UNCERTAINTY. UPPER/SURFACE
FLOW BECOMES SOUTHERLY ON WEDNESDAY WITH BOTH MODELS SHOWING A WEAK
EMBEDDED WAVE ALOFT. THE ECMWF SHOWS LIGHT QPF SIGNAL WITH THIS
FEATURE WHILE THE GFS REMAINS DRY. WILL INCLUDE A SLIGHT CHANCE OF
SHOWERS/THUNDER FOR NOW. OTHERWISE...LOOKS LIKE TEMPERATURES WILL
START OFF SOME 10 DEGREES ABOVE NORMAL ON SUNDAY IN THE MID 70-LOWER
80S...THEN NEAR NORMAL IN THE 70S MON/TUE/WED.
&&
.AVIATION...TODAY AND TONIGHT
618 AM CDT THU MAY 17 2012
BREEZY VFR CONDITIONS EXPECTED THROUGH THE PERIOD. AS A STORM
SYSTEM DEVELOPS OVER SOUTH DAKOTA TODAY...THE GRADIENT WILL
TIGHTEN OVER THE REGION. THIS WILL PRODUCE SOUTH WINDS AT BOTH TAF
SITES WITH SUSTAINED SPEEDS AROUND 20 KNOTS. GUSTS WILL DEVELOP BY
MID TO LATE MORNING AND CONTINUE INTO THE EARLY EVENING. KLSE
SHOULD GUST TO AROUND 25 KNOTS WITH GUSTS TO AROUND 30 KNOTS
EXPECTED AT KRST. THE GUSTS SHOULD DIMINISH BY EARLY EVENING BUT
LOOK FOR SUSTAINED SPEEDS TO REMAIN BETWEEN 10 AND 15 KNOTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
315 AM CDT THU MAY 17 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
315 AM CDT THU MAY 17 2012
.SHORT TERM...TONIGHT THROUGH SATURDAY
315 AM CDT THU MAY 17 2012
FORECAST CONCERNS INCLUDE SHRA CHANCES ACROSS THE NORTH TODAY AND
THEN INCREASING WARMTH THROUGH THE REMAINDER OF THE PERIOD.
LATEST WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW RIDGING OVER THE
IMMEDIATE FORECAST AREA WITH A WEAK MID-LEVEL TROUGH OVER THE
NORTHERN PLAINS. SURFACE ANALYSIS AT 3 AM HAS HIGH PRESSURE OVER THE
GREAT LAKES REGION WITH AN AREA OF LOW PRESSURE OVER THE NORTHERN
PLAINS. A WARM FRONT EXTENDED FROM THIS LOW EAST-SOUTHEASTWARD
ACROSS SOUTHERN MN INTO NORTHEAST IA. MOISTURE TRANSPORT/ISENTROPIC
LIFT AHEAD OF THE LOW AND OVER THE WARM FRONT WAS PRODUCING SOME
VERY HIGH-BASED SHRA/ISOLATED THUNDER ACROSS CENTRAL SD INTO FAR
SOUTHWEST MN.
17.00Z NCEP MODELS/17.21Z SREF IN GOOD AGREEMENT WITH OVERALL
SYNOPTIC SETUP THROUGH THE PERIOD.
FOR TODAY...LOW PRESSURE WILL STAY PUT ACROSS THE NORTHERN PLAINS AS
THE WARM FRONT LIFTS NORTH INTO CENTRAL MN/NORTHERN WI BY EARLY THIS
EVENING. AXIS OF LIGHT TO MODERATE 925-850MB MOISTURE TRANSPORT
STAYS NORTH OF THE AREA WITH BULK FAIRLY STRONG ISENTROPIC LIFT
FOLLOWING SUIT. EITHER WAY...LOWEST 700-600MB VERY DRY AS EVIDENCED
BY THE 17.00Z MPX SOUNDING AND NAM BUFKIT SOUNDINGS. MOST SHRA
ACTIVITY WILL BE FALLING OUT OF ACCAS CLOUD AT OR ABOVE 10-12KFT.
WOULD TAKE VIGOROUS CONVECTION FOR ANYTHING TO REACH THE GROUND. AS
SUCH...HAVE TRIMMED POPS FARTHER NORTH AND KEPT A SMALL CHANCE OF
SHRA/ISOLD THUNDER CONFINED NORTH OF HIGHWAY 10 IN WISCONSIN.
OTHERWISE...LOOK FOR INCREASING SOUTH WINDS TODAY WITH INCREASING
PRESSURE GRADIENT. WINDS ACROSS MUCH OF THE AREA SHOULD BE IN THE
15-25 MPH RANGE...BUT THE HIGHER/MORE WIND-PRONE AREAS OF SOUTHEAST
MN/NORTHEAST IA WILL LIKELY SEE WINDS MORE IN THE 20-25 MPH RANGE
WITH GUSTS AROUND 35 MPH. WITH WARM ADVECTION/RISING MOTIONS IN THE
BOUNDARY LAYER MITIGATING DOWNWARD TRANSFER OF STRONGER WINDS
ALOFT...FEEL WINDS WILL BE JUST SHY OF WIND ADVISORY. WILL HAVE TO
KEEP A CLOSE EYE ON THIS. TEMPERATURES ARE EXPECTED TO RESPOND TO
INCREASING SOUTHERLY FLOW WITH AFTERNOON HIGHS TOPPING OFF IN THE
UPPER 60S ACROSS NORTHERN WISCONSIN...TO THE MID-UPPER 70S
ELSEWHERE.
WARM FRONT PUSHES NORTH OF THE AREA THIS EVENING WITH A STRONG CAP
SETTING UP ACROSS THE AREA IN THE WARM SECTOR ON FRIDAY. WITH MOSTLY
SUNNY SKIES AND STRONG SOUTHERLY FLOW...TEMPERATURES SHOULD HAVE NO
PROBLEM REACHING INTO THE UPPER 70S TO MIDDLE 80S. DEW POINTS WILL
ALSO BE ON THE RISE INTO THE 50S FOR A SLIGHTLY MORE MUGGY FEEL
COMPARED TO THE LAST FEW DAYS.
COLD FRONT AND ASSOCIATED CONVECTION OVER THE NORTHERN PLAINS MAKES A MOVE
EASTWARD INTO MN/WESTERN IA ON SATURDAY WITH CAP HOLDING FIRM ACROSS
OUR FORECAST AREA. CONTINUED STRONG SOUTHERLY FLOW AND PARTLY TO
MOSTLY SUNNY SKIES SHOULD PUSH TEMPERATURES INTO THE MID-UPPER 80S.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
315 AM CDT THU MAY 17 2012
17.00Z ECMWF/GFS STILL SHOWING DIFFERENCE IN TIMING OF THE COLD
FRONTAL PASSAGE ACROSS THE AREA/ASSOCIATED SHRA/TS CHANCES IN THE SATURDAY
NIGHT/SUNDAY TIME FRAME. THE GFS REMAINS THE FASTER OF THE TWO
MODELS WITH PASSAGE AROUND 18Z WHEREAS THE ECMWF HOLDS OFF TIL
EVENING. WITH THIS UNCERTAINTY...WILL KEEP MODEL CONSENSUS APPROACH
GOING FOR NOW. WITH SLOWER TIMING...THERE STANDS A CHANCE FOR
STRONG/SEVERE THUNDERSTORMS WITH AMPLE CAPE/BULK SHEAR DEPICTED BY
THE ECMWF. HOPEFULLY THE MODELS WILL HAVE THIS RESOLVED A BIT BETTER
WITHIN THE NEXT FEW RUNS. MODELS THEN KEEP DIFFERENCES GOING THROUGH
THE REMAINDER OF THE PERIOD WITH THE GFS MAINTAINING A MORE
PROGRESSIVE WAVE PATTERN COMPARED TO THE ECMWF. ECMWF KEEPS
TROUGH/COOLER CYCLONIC FLOW AROUND THE AREA SUNDAY NIGHT THROUGH
TUESDAY FOR A SMALL CHANCE OF SHOWERS/ISOLATED THUNDER. THE GFS
BRINGS RIDGING IN FAIRLY QUICK FOR A DRIER SOLUTION. WILL KEEP MODEL
CONSENSUS GOING HERE AS WELL DUE TO THE UNCERTAINTY. UPPER/SURFACE
FLOW BECOMES SOUTHERLY ON WEDNESDAY WITH BOTH MODELS SHOWING A WEAK
EMBEDDED WAVE ALOFT. THE ECMWF SHOWS LIGHT QPF SIGNAL WITH THIS
FEATURE WHILE THE GFS REMAINS DRY. WILL INCLUDE A SLIGHT CHANCE OF
SHOWERS/THUNDER FOR NOW. OTHERWISE...LOOKS LIKE TEMPERATURES WILL
START OFF SOME 10 DEGREES ABOVE NORMAL ON SUNDAY IN THE MID 70-LOWER
80S...THEN NEAR NORMAL IN THE 70S MON/TUE/WED.
&&
.AVIATION...THROUGH 06Z FRIDAY
1151 PM CDT WED MAY 16 2012
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. WINDS WILL
CONTINUE TO SWING AROUND TO THE SOUTH OVERNIGHT AS THE SURFACE
HIGH SLIDES EASTWARD. MOISTURE TRANSPORT WILL NOSE INTO WESTERN
MINNESOTA BETWEEN 09Z-12Z TONIGHT WHICH WILL RESULT IN SOME
SHOWERS. THESE SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED TO
LIFT EAST-NORTHEAST AND REMAIN NORTH OF THE TAF SITES THROUGH
THURSDAY. 17.01Z HRRR DOES SHOW THE SHOWERS JUST SKIRTING
KRST...BUT WILL LEAVE ANY MENTION OUT OF THE FORECAST AT THIS
TIME...WITH ONLY A SCT-BKN BAND OF MID LEVEL CLOUDS. PRESSURE
GRADIENT WILL TIGHTEN LATE THIS MORNING...BETWEEN 15Z-18Z WITH
SOUTH WINDS INCREASING WITH SOME GUSTS TO BETWEEN 25 AND 35 KNOTS.
WINDS WILL SUBSIDE AFTER 00Z...BUT STILL REMAIN ABOVE 12 KNOTS AT
KRST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
315 AM CDT THU MAY 17 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1151 PM CDT WED MAY 16 2012
.SHORT TERM...TONIGHT THROUGH SATURDAY
237 PM CDT WED MAY 16 2012
MAIN FORECAST CONCERNS ARE ON BREEZY SOUTH WINDS ON THURSDAY ALONG
WITH SHOWER CHANCES ACROSS PORTIONS OF SOUTHEAST MINNESOTA INTO NORTH
CENTRAL WISCONSIN. FOCUS THEN TURNS TO TEMPERATURES FRIDAY INTO
SATURDAY.
AT 235 PM...SURFACE ANALYSIS PLACED A SURFACE RIDGE OF HIGH
PRESSURE CENTERED OVER THE UPPER MISSISSIPPI RIVER VALLEY. SKIES
WERE SUNNY ACROSS THE FORECAST AREA WITH AFTERNOON TEMPERATURES
RANGING FROM THE LOWER 60S ACROSS NORTH CENTRAL WISCONSIN TO
AROUND 70 ACROSS NORTHEAST IOWA.
THE HIGH WILL SLIDE EAST OF THE FORECAST AREA TONIGHT AS A TROUGH
DIGS INTO THE WESTERN CONUS. SURFACE LOW PRESSURE NEAR THE
MONTANA/SASKATCHEWAN BORDER WILL DEEPEN TONIGHT. A SURFACE TROUGH
IS EXPECTED TO EXTEND SOUTH THROUGH THE WESTERN DAKOTAS/NEBRASKA
PANHANDLE INTO EASTERN COLORADO. SOUTHERLY FLOW WILL INCREASE
ACROSS THE FORECAST AREA AHEAD OF THIS SYSTEM LATE TONIGHT INTO
EARLY THURSDAY MORNING AS A WARM FRONT PUSHES EAST ACROSS
MINNESOTA...AND IS EXPECTED TO BE POSITIONED ALONG THE MISSISSIPPI
RIVER AROUND 12Z. 850 MB MOISTURE TRANSPORT WILL BE FOCUSED INTO
NORTHERN MINNESOTA/NORTHWEST WISCONSIN THROUGH MUCH OF THE DAY ON
THURSDAY SO WOULD EXPECT THE BEST CHANCES FOR SHOWERS AND
THUNDERSTORMS ACROSS THESE AREAS. CANNOT RULE OUT A FEW SPRINKLES
OR LIGHT RAIN SHOWERS ACROSS NORTH CENTRAL INTO WEST CENTRAL
WISCONSIN LATE THURSDAY MORNING INTO THURSDAY AFTERNOON AS A WEAK
UPPER LEVEL SHORTWAVE MOVES EAST ACROSS CENTRAL MINNESOTA INTO
CENTRAL WISCONSIN. FORECAST SOUNDINGS SHOW A VERY DRY LAYER FROM
THE SURFACE THROUGH 600 MB. PRECIPITATION WILL HAVE A TOUGH TIME
MAKING IT THROUGH THIS LAYER. SHOULD SEE MAINLY A MID CLOUD DECK
OR POSSIBLY SOME ALTOCUMULUS CASTELLANAS/ACCAS/ THURSDAY MORNING
INTO THURSDAY AFTERNOON. WILL MAINTAIN SHOWER CHANCES ACROSS
PORTIONS OF SOUTHEAST MINNESOTA AND NORTH CENTRAL INTO WEST
CENTRAL WISCONSIN TO ACCOUNT FOR A FEW LIGHT SHOWERS OR SPRINKLES.
FORECAST SOUNDINGS ACROSS NORTH CENTRAL WISCONSIN INDICATING
AROUND 277 J/KG ELEVATED CAPE LIFTING FROM 600 THROUGH 300 MB...SO
WOULD EXPECT THIS INSTABILITY GO INTO ACCAS PRODUCTION. MUCH
WARMER AIR WILL MOVE INTO THE REGION BEHIND THE FRONT WITH 850 MB
TEMPERATURES WARMING TO AROUND 17 C BY LATE THURSDAY AFTERNOON.
HIGHS WILL CLIMB INTO THE UPPER 70S TO AROUND 80 ACROSS SOUTHEAST
MINNESOTA INTO NORTHEAST IOWA...WITH HIGHS RANGING FROM THE UPPER
60S ACROSS NORTH CENTRAL WISCONSIN TO THE UPPER 70S ACROSS FAR
SOUTHWEST WISCONSIN. IT WILL BE RATHER BREEZY ON
THURSDAY...ESPECIALLY ACROSS THE OPEN AREAS OF SOUTHEAST
MINNESOTA/NORTHEAST IOWA...AND THE BLUFF TOPS ACROSS WESTERN
WISCONSIN...WHERE SUSTAINED SOUTH WINDS OF 20 TO 25 MPH ARE
EXPECTED WITH GUSTS AROUND 44 MPH POSSIBLE DURING PEAK HEATING. IT
APPEARS THE WINDS WILL BE JUST SHY OF WIND ADVISORY CRITERIA SO
WILL HOLD OFF ON ISSUING AN ADVISORY. HOWEVER...WILL BE INCREASING
WIND SPEEDS ACROSS MUCH OF THE FORECAST AREA.
THE WARM FRONT WILL LIFT INTO UPPER MICHIGAN AND EXTREME NORTHERN
MINNESOTA THURSDAY EVENING. SHOWER AND THUNDERSTORM CHANCES WILL
SHIFT NORTH OF THE FORECAST AREA AS 850 MB MOISTURE TRANSPORT
REMAINS FOCUSES NORTH AND WEST OF THE AREA. IN ADDITION...UPPER
LEVEL RIDGING WILL BE BUILDING ACROSS THE FORECAST AREA...WITH NO
APPRECIABLE UPPER LEVEL FORCING TO GENERATE PRECIPITATION. UNDER
MOSTLY CLEAR SKIES...SOUTHERLY WINDS WILL KEEP TEMPERATURES ON THE
MILD SIDE THURSDAY NIGHT WITH LOWS RANGING FROM THE LOWER 60S ACROSS
SOUTHEAST MINNESOTA INTO NORTHEAST IOWA...TO THE MID 50S ACROSS
CENTRAL INTO FAR SOUTHWEST WISCONSIN.
A WARM DAY IS ON TAP FOR THE REGION ON FRIDAY WITH HIGHS RANGING
FROM THE LOWER 80S ACROSS NORTH CENTRAL WISCONSIN TO THE UPPER 80S
ACROSS NORTHEAST IOWA. IN ADDITION...HIGHER DEWPOINTS WILL MAKE A
RETURN TO THE AREA WITH DEWPOINTS CLIMBING INTO THE UPPER 50S TO
LOWER 60S. THE COMBINATION OF THESE TEMPERATURES AND DEWPOINTS WILL
MAKE IT FEEL A LITTLE ON THE MUGGY SIDE COMPARED TO THE DRY AIR WE
EXPERIENCED THIS PAST WEEK. ANOTHER BREEZY DAY IS EXPECTED WITH
SOUTH WINDS IN THE 15 TO 20 MPH RANGE...POSSIBLY GUSTING TO AROUND
30 MPH AT TIMES IN THE OPEN AREAS OF SOUTHEAST MINNESOTA AND
NORTHEAST IOWA. THE TROUGH OVER THE WESTERN US WILL MOVE EAST INTO
THE PLAINS FRIDAY NIGHT INTO SATURDAY WITH THE SURFACE LOW LIFTING
NORTH OUT OF THE DAKOTAS INTO WESTERN ONTARIO. A COLD FRONT WILL
DRIFT INTO WESTERN MINNESOTA BY LATE SATURDAY AFTERNOON WITH
SHOWERS/THUNDERSTORMS EXPECTED AHEAD OF THE FRONT. ANOTHER WARM
DAY IS EXPECTED ACROSS THE FORECAST AREA WITH HIGHS CLIMBING INTO
THE MID TO UPPER 80S UNDER PARTLY SUNNY SKIES. IN
ADDITION...DEWPOINTS WILL REMAIN IN THE UPPER 50S TO LOWER 60S
MAKING IT FEEL A LITTLE ON THE MUGGY SIDE. THE COLD FRONT IS
EXPECTED TO REMAIN WEST OF THE FORECAST AREA ON SATURDAY.
AFTERNOON MUCAPE VALUES INCREASING INTO THE 1500 TO 2000 J/KG
RANGE. FORECAST SOUNDINGS SHOW A WEAK CAP IN PLACE BY SATURDAY
AFTERNOON. NOT EXPECTING TO SEE MUCH DEVELOPMENT WITH VIRTUALLY NO
FORCING TO HELP SPARK SHOWERS/THUNDERSTORM UNTIL THE COLD FRONT
MOVES IN. EVEN IF STORMS COULD DEVELOP...SHEAR IS VERY WEAK SO
WOULD NOT EXPECT TO SEE SEVERE THUNDERSTORMS DURING THE DAY ON
SATURDAY.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
237 PM CDT WED MAY 16 2012
16.12 FORECAST MODELS SHOWING SOME SLIGHT DIFFERENCES IN TIMING OF
THE COLD FRONT MOVING THROUGH THE FORECAST AREA SATURDAY NIGHT
THROUGH SUNDAY. THE GFS/GEM ARE THE FASTER SOLUTIONS...BRINGING THE
FRONT THROUGH THE FORECAST AREA LATE SATURDAY NIGHT INTO EARLY
SUNDAY AFTERNOON. THE ECMWF IS A LITTLE SLOWER...BRINGING THE FRONT
THROUGH THE AREA LATE SUNDAY AFTERNOON INTO SUNDAY EVENING. 0-6 KM
BULK SHEAR VALUES INCREASE ACROSS THE AREA SATURDAY NIGHT THROUGH
SUNDAY INTO THE 30 TO 35 KT RANGE. DEPENDING ON THE TIMING OF THE
FRONT STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE BUT DO NOT APPEAR
LIKELY AT THIS TIME. GIVEN THE UNCERTAINTY ON EXACTLY WHEN THE FRONT
WILL MOVE THROUGH...ITS DIFFICULT TO PIN DOWN EXACT SEVERE WEATHER
THREATS AT THIS TIME IF IT OCCURS. WEAK HIGH PRESSURE WILL BUILD
INTO THE REGION BEHIND THE FRONT MONDAY NIGHT INTO TUESDAY. LOOK
FOR HIGHS TO FALL BACK INTO THE 70S ON MONDAY. THE HIGH LOOKS TO
SLIDE EAST OF THE AREA TUESDAY NIGHT INTO WEDNESDAY AS A TROUGH
MOVES ACROSS THE PACIFIC NORTHWEST AND PUSHES EAST THROUGH THE
DAKOTAS ON TUESDAY NIGHT INTO WEDNESDAY. SOUTHERLY FLOW WILL
INCREASE AHEAD OF THIS SYSTEM PUMPING MOIST UNSTABLE AIR BACK INTO
THE REGION. FLOW ALOFT LOOKS TO TURN SOUTHWEST ON WEDNESDAY AS THE
TROUGH PUSHES EAST INTO THE UPPER MISSISSIPPI RIVER VALLEY.
EMBEDDED SHORTWAVE COULD TRIGGER SHOWERS AND THUNDERSTORMS ACROSS
THE REGION WEDNESDAY INTO WEDNESDAY NIGHT. MODELS ARE HINTING AT
AN ACTIVE PATTERN TO END THE WEEK BUT WILL HAVE TO TAKE A CLOSER
LOOK AT THIS WITH LATER MODEL RUNS.
&&
.AVIATION...THROUGH 06Z FRIDAY
1151 PM CDT WED MAY 16 2012
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. WINDS WILL
CONTINUE TO SWING AROUND TO THE SOUTH OVERNIGHT AS THE SURFACE
HIGH SLIDES EASTWARD. MOISTURE TRANSPORT WILL NOSE INTO WESTERN
MINNESOTA BETWEEN 09Z-12Z TONIGHT WHICH WILL RESULT IN SOME
SHOWERS. THESE SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED TO
LIFT EAST-NORTHEAST AND REMAIN NORTH OF THE TAF SITES THROUGH
THURSDAY. 17.01Z HRRR DOES SHOW THE SHOWERS JUST SKIRTING
KRST...BUT WILL LEAVE ANY MENTION OUT OF THE FORECAST AT THIS
TIME...WITH ONLY A SCT-BKN BAND OF MID LEVEL CLOUDS. PRESSURE
GRADIENT WILL TIGHTEN LATE THIS MORNING...BETWEEN 15Z-18Z WITH
SOUTH WINDS INCREASING WITH SOME GUSTS TO BETWEEN 25 AND 35 KNOTS.
WINDS WILL SUBSIDE AFTER 00Z...BUT STILL REMAIN ABOVE 12 KNOTS AT
KRST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
237 PM CDT WED MAY 16 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS DENVER CO
353 AM MDT SAT MAY 19 2012
.SHORT TERM...WATER VAPOR IMAGERY SHOWING UPPER LOW NOW MOVING
ACROSS WESTERN COLORADO WITH SCATTERED SHOWERS INCREASING ACROSS
THE NORTHERN MOUNTAINS ATTM. RUC QG ANALYSIS SHOWING WEAK TO MODERATE
ASCENT NOW INTO THE MOUNTAINS AND THIS WILL SPREAD OVER INTO THE
NORTHEAST PLAINS THIS MORNING. MEANWHILE...COLD FRONT HAS MOVED
THROUGH ALL OF NORTHEAST COLORADO WITH SHALLOW N-NE UPSLOPE FLOW
DEVELOPING OVER THE PAST FEW HOURS. SURFACE DEWPOINTS HAVE BEEN
RISING INTO THE MID 40S AND WE SHOULD START SEEING SOME STRATUS
DEVELOPING BETWEEN 09-12Z ACROSS THE FRONT RANGE GIVEN THE ASCENT
AND UPSLOPE DEVELOPING. SHORT RANGE MODELS STILL SHOWING A
MOISTENING AIRMASS THIS MORNING WITH SHOWERS SPREADING OUT OVER THE
PLAINS. CURRENT LIKELY POPS STILL SEEM REASONABLE BUT AMOUNTS
STILL LOOK TO BE ON THE LOW SIDE AS THE TROF WILL MOVING MOVING
RIGHT ALONG AND NOT A TON OF DEEP MOISTURE DEVELOPING WITH THIS
QUICK MOVING SYSTEM. TEMPERATURES MUCH COOLER TODAY WITH READINGS
ONLY IN THE 50S AND LOWER 60S OVER THE PLAINS. MAY SEE SOME LIGHT
SNOW ACCUMULATIONS IN THE MOUNTAINS AND WITH THE MORE SCATTERED
NATURE DON`T SEEM MUCH MORE THAN 2-4 INCHES IN THE HIGHER
MOUNTAINS. POSSIBLY A BIT MORE IN THE HEAVIER EMBEDDED CONVECTIVE
SNOW SHOWER. BOTH NAM/GFS SEEM A BIT HIGH WITH LIQUID AMOUNTS OVER
AN INCH IN MOUNTAINS AND HIGHER EAST SLOPES.
THE LOW WILL HAVE MOVED INTO WESTERN KANSAS BY LATE IN THE DAY
WITH SUBSIDENCE SPREADING OVER THE PLAINS THIS AFTERNOON. HENCE A
DECREASE IN SHOWER ACTIVITY AND ENDING IN MOST LOCALES DURING THE
EVENING HOURS. GRADUAL CLEARING OVERNIGHT ACROSS THE ENTIRE AREA.
.LONG TERM...NORTHEAST COLORADO UNDER WEST-NORTHWESTERLY FLOW ALOFT
WITH THE SHORTWAVE TROUGH CONTINUING ITS EASTWARD PROGRESSION
ACROSS THE CENTRAL GREAT PLAINS DURING THE DAY SUNDAY. SHOULD SEE
A WARMER DAY WITH A 2C WARMING AT 700 MBS. MODELS ALSO SHOW
S-SELY SFC WINDS ON THE PLAINS STEADILY STRENGTHENING DURING THE
DAY WHICH AIDS IN TRANSPORTING INCREASINGLY HUMID AIR NORTHWARD
UP ALONG THE FRONT RANGE. STEEP LAPSE RATES DUE TO STG DAYTIME
HEATING AND THE ARRIVAL OF THIS MOISTURE SHOULD SUPPORT AT LEAST
ISOLATED T-STORM DEVELOP OVER AND NEAR THE FRONT RANGE DURING THE
AFTERNOON AND EVENING HOURS. STORMS MOVING OUT ACROSS THE PLAINS
MAY LINGER WELL INTO THE EVENING WITH THIS MOIST SELY INFLOW.
ON MONDAY...FCST AREA BENEATH A STG 500 MB HIGH PRESSURE RIDGE WITH
TEMPERATURES ALOFT CONTINUING TO WARM. A BRISK SOUTHERLY LOW-
LEVEL FLOW ON THE PLAINS WILL CONTINUE TO ADVECT MOISTURE UP INTO
THE AREA. BY AFTERNOON...MODELS SHOW AN 850-700 THETA-E RIDGE AXIS
ALIGNED FM COLORADO SPRINGS TO JULESBURG. ALONG THIS AXIS SFC
BASED CAPES PROGGED IN THE 1200-2000 KG/J RANGE BY LATE IN THE
DAY. HOWEVER STG WARMING ALOFT AND WEAK CIN POSSIBLY ENOUGH TO
SUPPRESS CONVECTION. FOR NOW WILL LEAVE OUT MENTION OF T-STORMS ON
THE PLAINS...BUT CAN/T RULE THEM OUT ENTIRELY. WHEREAS WILL
MENTION AT LEAST A SLIGHT CHANCE OF T-STORMS OVER AND NEAR THE
FRONT RANGE FOR LATE IN THE DAY. GOING FOR TEMPERATURES ON MONDAY
IN THE LOWER-MID 80S AT LOWER ELEVATIONS WITH UPPER 50S- 70S IN
THE HIGH COUNTRY.
BY TUESDAY...UPPER RIDGE MOVES EAST OF THE STATE PLACING THE AREA
UNDER INCREASING SOUTHWESTERLY FLOW ALOFT. A DRIER MID-LEVEL WITH
SUBSIDENCE ON THE SOUTH SIDE OF AN APPROACHING UPPER AIR TROUGH
SHOULD RESULT IN PLENTY OF SUNSHINE DURING THE MORNING HOURS.
COMBINATION OF UNSEASONABLY WARM TEMPERATURES...LOW HUMIDITY AND
AND STEEP LAPSE RATES WILL LIKELY INCREASE THE WILDLAND FIRE
DANGER IN MANY AREAS. NOT UNTIL LATE IN THE DAY WHEN THE UPPER
TROUGH NEARS WILL SEE CONVECTION...MOST OF WHICH SHOULD BE
CONFINED TO THE HIGHER TERRAIN NORTH OF I-70. SHOULD SEE ANOTHER
DAY OF VERY WARM TEMPERATURES WITH HIGHS PUSHING THE 90 DEG MARK
ON THE PLAINS.
BY WEDNESDAY TEMPERATURES TURN COOLER WITH PASSAGE OF THE UPPER
TROUGH AND PASSAGE OF A COLD FRONT DURING THE DAY. SHOULD SEE THE
CHANCE FOR SHOWERS AND T-STORMS ALSO INCREASE. THE UPPER TROUGH
PASSES TO THE EAST OVERNIGHT RESULTING IN A SLIGHT MODERATION IN
TEMPERATURE AND A REDUCED CHANCE IN PRECIP. FOR LATER IN THE
WEEK...SHOULD SEE STEADY WARMING WITH THE RETURN OF RIDGING.
&&
.AVIATION...CEILINGS LOWERING BY DAYBREAK WITH MAINLY MVFR/ILS
APPROACHES THROUGH THIS MORNING WITH RAIN SHOWERS AND THEN
IMPROVING TRENDS DURING THE AFTERNOON. SURFACE WINDS SHOULD REMAIN
N-NE TODAY BEFORE SHIFTING SE-S BY LATER THIS EVENING AND A RETURN
TO DRAINAGE.
&&
.HYDROLOGY...RAINFALL AMOUNTS LOOK TO BE IN THE QUARTER TO HALF
INCH RANGE FOR TODAY WITH RAINFALL RATES GENERALLY A TENTH OF AN
INCH PER HOUR OR LESS WITH THE SHOWERS. ANY FLOODING POTENTIAL IN THE
BURN AREAS SEEM LOW.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....BAKER
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS MIAMI FL
347 AM EDT SAT MAY 19 2012
.SHORT RANGE (TODAY-MONDAY)...
RECENTLY ANIMATED WATER VAPOR LOOP SHOWED A BROAD TROUGH CENTERED
OVER THE SOUTHEAST WITH A NOTABLE SHORTWAVE TROUGH EXTENDING
SOUTHWEST FROM THE FLORIDA PANHANDLE TO THE CENTRAL GULF AND PLENTY
OF MID/UPPER MOISTURE SPREADING EAST-NORTHEAST ACROSS SOUTH
FLORIDA...THE KEYS AND FLORIDA STRAITS. THE LATEST SURFACE ANALYSIS
SHOWED A WEAKNESS WITHIN THE SUBTROPICAL RIDGE ACROSS THE LOCAL AREA
WITH A TROUGH OR FRONTAL BOUNDARY EXTENDING SOUTHWEST FROM A LOW
PRESSURE CENTERED OFF THE CAROLINA COAST TO CENTRAL FL.
THE MODELS HAVE INITIALIZED WELL WITH THIS SYNOPTIC PATTERN AND
INDICATE ANOTHER POTENTIALLY ACTIVE DAY ACROSS THE FLORIDA
PENINSULA...SIMILAR TO YESTERDAY. THE AFOREMENTIONED SHORTWAVE
TROUGH WILL ROTATE EASTWARD AROUND THE BASE OF THE UPPER TROUGH
AND MOVE ACROSS THE AREA TODAY FROM WEST TO EAST...WHICH WILL LEAD
TO DECREASING UPPER HEIGHTS AND SOME COOLER MID-LEVEL AIR (-10 TO
-11 C 500 MB TEMPS) SPREADING OVER THE AREA THIS AFTERNOON. THIS
COMBINED WITH A WEAK SFC TROUGH AND LOW-LEVEL CONVERGENCE
ASSOCIATED WITH THE EAST/WEST COAST SEA BREEZES WILL BE ENOUGH TO
INITIATE ANOTHER ROUND OF AFTERNOON CONVECTION. THE ONE DIFFERENCE
TODAY COMPARED TO YESTERDAY IS THAT THE LOW-LEVEL FLOW WILL HAVE
MORE OF AN EASTERLY COMPONENT...WHICH SHOULD HELP CONCENTRATE THE
CONVECTIVE ACTIVITY OVER THE INTERIOR SECTIONS INITIALLY. THE
LATEST HRRR MODEL REFLECTIVITIES LINE UP WELL WITH THIS AND
GENERALLY INDICATE CONVECTION BEGINNING BY 18Z OVER THESE INTERIOR
LOCATIONS. WITH THE DRIER/COOLER MID-LEVEL AIR EXPECTED...THE MAIN
THREATS WITH THE STRONGER STORMS THAT DEVELOP WILL BE DAMAGING
STRAIGHT LINE WINDS AND HAIL.
TONIGHT THROUGH MONDAY...SIMILAR CONDITIONS WILL BE EXPECTED EACH
DAY WITH SCATTERED AFTERNOON SHOWERS/TSTMS DEVELOPING OVER THE
INTERIOR SECTIONS ASSOCIATED WITH THE PERSISTENT UPPER TROUGH AND
AFTERNOON SEA BREEZES.
.LONG RANGE (MONDAY NIGHT-FRIDAY)...
THE GFS/GFS ENSEMBLE MEAN/ECMWF GENERALLY ALL MAINTAIN THE
MID/UPPER TROUGH OVER THE SOUTHEAST REGION WITH DRY MID/UPPER
WESTERLY FLOW CONTINUING ACROSS THE FL PENINSULA. AT THE
SURFACE...ALTHOUGH THERE REMAINS SOME DIFFERENCES NOTED BETWEEN THE
MODEL SOLUTIONS...THE GFS/ECMWF GENERALLY INDICATE A WEAK TROUGH
EXTENDING NORTHEAST FROM A BROAD LOW CENTERED OVER THE WESTERN
CARIBBEAN ACROSS THE FLORIDA STRAITS...WHICH MAY HELP CONCENTRATE
ANY DEEP MOIST CONVECTION JUST SOUTH OF OUR LOCAL AREA ACROSS THE
KEYS AND STRAITS. OTHERWISE...MORE OF A SEASONAL PATTERN WITH 20-30
PERCENT RAINFALL CHANCES EACH DAY ASSOCIATED WITH THE AFTERNOON SEA
BREEZES WILL REMAIN IN THE FORECAST. TEMPERATURES WILL REMAIN AROUND
NORMAL THROUGH THIS TIME WITH HIGHS IN THE UPPER 80S AND LOWS IN THE
LOWER 70S.
&&
.MARINE...
A WEAK PRESSURE GRADIENT WILL RESULT IN LIGHT EASTERLY WINDS
AND LOW SEAS CONTINUING THROUGH THE WEEKEND AND INTO THE UPCOMING
WEEK. SCATTERED SHOWERS AND THUNDERSTORMS COULD LEAD TO BRIEF
PERIODS WITH LOCALLY HIGHER WINDS AND SEAS.
&&
.AVIATION...
THE WINDS WILL REMAIN LIGHT EARLY THIS MORNING BEFORE BECOMING
SOUTHEAST AT 5 TO 10 KNOTS AFTER 13Z TODAY. THE ONLY EXCEPTION TO
THIS IS AT KAPF WHERE THE WINDS WILL BE EASTERLY THIS MORNING
BEFORE SWINGING TO A WESTERLY DIRECTION AROUND 17Z TODAY...DUE TO
THE WEST COAST SEA BREEZE DEVELOPING AND PUSHING INLAND.
THE WEATHER WILL ALSO REMAIN DRY THROUGH 13Z TODAY...BEFORE VCSH
FOR ALL TAF SITES BETWEEN 13Z AND 17Z. THUNDERSTORMS WILL THEN
DEVELOP THIS AFTERNOON ALONG THE SEA BREEZE AND PUSH SLOWLY INLAND
OVER THE COAST AREAS...WHILE THE WEST COAST SEA BREEZE PUSHES MORE
INLAND. SO WILL INTRODUCE VCTS FOR THE EAST COAST TAF SITES
BETWEEN 17Z AND 23Z TODAY...WHILE THE KAPF TAF SITE REMAINS IN THE
VCSH FOR THE AFTERNOON HOURS. THE ACTIVITY WILL THEN DISSIPATE
BETWEEN 00Z AND 02Z TONIGHT OVER ALL OF THE TAF SITES...AS THE
HEATING OF THE DAY IS LOST. SO AFTER 02Z TONIGHT THE WEATHER WILL
BE DRY AGAIN.
THE CEILING AND VIS WILL REMAIN IN THE VFR CONDITIONS THROUGH
TODAY...DUE TO THE UNKNOWN TIMING OF THE SHOWERS AND THUNDERSTORMS
FOR TODAY.
&&
.FIRE WEATHER...
SOME STRONG TO SEVERE STORMS ARE POSSIBLE THIS AFTERNOON OVER
SOUTH FLORIDA ESPECIALLY WHERE THE EAST AND WEST COAST SEA BREEZES
COLLIDE OVER THE INTERIOR AREAS. THE PRIMARY IMPACTS FROM THE
STRONGEST STORMS WILL BE FREQUENT LIGHTNING STRIKES...GUSTY
WINDS...HAIL UP TO QUARTER SIZE...AND HEAVY RAINFALL. THE BEST
TIME TO SEE THE STORMS WILL IN THE AFTERNOON AND EARLY EVENING HOURS.
THE RELATIVE HUMIDITIES TODAY WILL REMAIN ABOVE THE 35 PERCENT
CRITICAL VALUE..AS THE DISPERSION INDEX WILL RANGE FROM THE 20S
INTERIOR AREAS TO 40 ALONG THE METRO AREAS. THE DISPERSION INDEX
FOR TONIGHT WILL BE LESS THAN 5. THIS MEANS THAT THE MIXING FOR
TODAY IS IN THE FAIR TO GOOD RANGE...WHILE TONIGHT IT IS IN THE
VERY POOR RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 85 71 85 73 / 50 50 30 20
FORT LAUDERDALE 85 72 86 74 / 50 50 30 20
MIAMI 86 73 86 73 / 50 50 30 20
NAPLES 86 70 86 71 / 40 20 40 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...54/BNB
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
305 AM CDT SAT MAY 19 2012
.SYNOPSIS...
06Z SFC ANALYSIS HAS THE FRONT WITH LOW PRESSURE CENTERS ALONG IT
RUNNING FROM NORTHWEST MINNESOTA INTO NORTHERN COLORADO. A MESO HIGH
ASSOCIATED WITH A SMALL MCS WAS ACROSS NEBRASKA WHILE A DRY LINE RAN
FROM FROM NEAR KMCK TO KCVS. DEW POINTS WERE IN THE 40S ACROSS THE
GREAT LAKES WITH 50S OVER MUCH OF THE MIDWEST.
&&
.SHORT TERM...TODAY AND TONIGHT
VERY WARM AND BREEZY CONDITIONS WILL BE SEEN ACROSS THE AREA TODAY.
IF THE SAME NEAR 30 DEGREE DIURNAL SWING TAKES PLACE TODAY THEN MAX
TEMPS WOULD BE IN THE LOW TO MID 90S. THE OVERALL WAA AND DEPTH OF
DEEP MIXING JUST DOES NOT SUPPORT TEMPERATURES THAT WARM. HOWEVER...
PERSISTENCE PLUS SEVERAL DEGREES WOULD SUPPORT UPPER 80S TO LOWER
90S FOR MAX TEMPS. DEW POINTS WILL BE ROUGHLY 10 DEGREES WARMER THAN
YESTERDAY BUT HUMIDITY LEVELS WILL STILL BE LOW.
TONIGHT...THE EVENING HOURS WILL BE DRY. MCS AND LIFT TOOLS INDICATE
CONVECTION WILL FIRE LATE THIS AFTERNOON/EVENING IN WESTERN IOWA
PROBABLY NOT FAR FROM THE MISSOURI RIVER. THE QUESTION IS WHETHER
SAID CONVECTION WILL MAKE IT INTO THE CWFA PRIOR TO SUNRISE.
INTERESTINGLY...ALL MODELS WEAKEN THE CONVERGENCE AFTER MIDNIGHT
ACROSS THE AREA. MCS...LIFT...AND HEAVY RAIN TOOLS OFFER MIXED
SIGNALS ON PRECIPITATION POTENTIAL. WHEN THE LIFT TOOL IS APPLIED TO
ALL THE MODELS...A WEAK BUT CONSISTENT SIGNAL EMERGES SUGGESTING THE
POSSIBILITY OF CONVECTION ENTERING THE FAR WESTERN CWFA JUST PRIOR
TO DAWN. SO...WILL CONFINE ANY PRECIP TO VERY LATE TONIGHT OVER THE
WESTERN QUARTER OR SO OF THE CWFA. HOWEVER...THE CONSISTENT
WEAKENING OF THE OVERALL CONVERGENCE BY THE MODELS DOES QUESTION THE
POTENTIAL FOR ANY PRECIPITATION ENTERING THE CWFA. ..08..
.LONG TERM...SUNDAY THROUGH NEXT FRIDAY
SUNDAY THROUGH SUNDAY EVENING CONTINUES TO REPRESENT A FRONTAL
PASSAGE...WITH MODEST AT BEST MOISTURE...AND WEAK FORCING. THE
TIMING APPEARS TO HAVE SLOWED JUST ENOUGH TO HAVE THE FRONT WITHIN
EASTERN IOWA AT 18 TO 00Z...AND THUS A DIURNAL INCREASE IN
CONVECTION SHOULD AFFECT OUR CWA UNLESS THE TIMING SPEEDS UP AGAIN.
THE 18Z TO 00Z FROPA IS CONSISTENT IN MODEL GUIDANCE OTHER THAN THE
NAM...WHICH REMAINS 3 HOURS FASTER. QPF SHOULD BE GENERALLY
LIGHT...WITH BENEFICIAL AMOUNTS SPOTTY IN EXCESS OF A QUARTER INCH.
ANY STRONG STORMS WILL DEPEND GREATLY ON CAPE...AND AT THIS
POINT...WE ARE EXPECTING HIGHS IN THE LOWER TO MID 80S...WITH
DEWPOINTS AROUND 60. THIS WILL BE SUFFICIENT FOR THUNDER...BUT
DEPENDING ON WARM MID LEVEL TEMPS...WE MAY NOT SEE A LARGE CAPE
POOL.
BY LATER SUNDAY NIGHT...CAA AND DRY AIR SHOULD SWEEP IN...ENDING ANY
RAINFALL THREAT. MONDAY THROUGH TUESDAY...COOLER CANADIAN AIR SHOULD
BE OVER THE REGION...WITH HIGHS IN THE LOWER TO MID 70S...AND LOWS
IN THE LOWER TO MID 50S. THIS TWO DAY PERIOD REPRESENTS THE COOLEST
PORTION OF THE EXTENDED.
WEDNESDAY NIGHT THROUGH FRIDAY...THERE REMAIN LARGE DIFFERENCES IN
MODEL DATA. THE GFS CONTINUES TO SHIFT THE TROF/RIDGE EAST FAR
ENOUGH DURING THIS PERIOD TO WARRANT SHOWERS AND THUNDERSTORMS IN
OUR CWA BEGINNING THURSDAY. SHOULD THE GFS BE CORRECT...WITH SOME
SUPPORT FROM THE UKMET AS WELL...THIS MAY BE THE BEGINNING OF A 2 TO
4 DAY PERIOD OF ACTIVE STORMS. HOWEVER...CAPPING IS MOST CERTAINLY
GOING TO BE AN ISSUE...WITH THE ECMWF...CONSISTENTLY...SHOWING THE
ENTIRE PERIOD BEING HOT AND COMPLETELY DRY. WHILE BOTH
POSSIBILITIES REMAIN POSSIBLE...IT IS HARD TO IGNORE SUCH A STRONG
ECMWF SIGNAL TOWARDS SUNSHINE AND HOT AIR.
ERVIN
&&
.AVIATION...
VFR WX WILL CONTINUE THROUGH 08Z/20. RADAR PROFILES SUGGEST THE
POTENTIAL FOR LLWS THROUGH SUNRISE BUT THE RAP MODEL TRENDS HAVE
LOWER WIND SPEEDS IN THE 1-2KFT AGL LAYER. WINDS WILL PICK UP AROUND
15Z/19 AS THE INVERSION BREAKS AND WILL DROP AGAIN AROUND SUNSET.
AFT 08Z/20 CONVECTION IN THE FORM OF SHRA/TSRA MAY AFFECT KCID.
CONDITIONS SHOULD REMAIN VFR BUT IF TSRA DO AFFECT KCID THERE IS A
POTENTIAL FOR MVFR CONDITIONS. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
509 AM EDT SAT MAY 19 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 508 AM EDT SAT MAY 19 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG OVER THE
GREAT LAKES DOWNSTREAM OF TROF IN THE ROCKIES. CWA IS IN THE WARM
SECTOR E OF SFC-H85 TROF/COLD FNT AND S OF WARM FNT OVER NRN LK SUP/
ADJOINING ONTARIO. WITH DRYNESS SHOWN ON LOCAL 00Z RAOBS /H925 DEWPT
DEPRESSIONS ARE 15 TO 25C ON THE MPX/GRB RAOBS AND THE H85 DEWPT
DEPRESSION AT GRB WAS 49C/...SKIES ARE MOCLR OVER UPR MI. DESPITE
THE CLEAR SKIES/DRY AIR AND LOCAL DECOUPLING... TEMPS ARE WELL ABV
NORMAL WITH STEADY SW FLOW AT H925 LIMITING THE OVERALL DIURNAL TEMP
DROP. SOME SHRA/TS DID IMPACT MUCH OF MN THIS PAST EVNG DESPITE
FAIRLY DRY AIR.AS SHRTWV LIFTED NNEWD WELL E OF THE MAIN TROF TO THE
W...BUT THESE ARE TENDING TO WEAKEN AND STAY W OF EVEN LK SUP. MORE
WIDESPREAD SHRA/TS ARE LOCATED IN THE PLAINS CLOSER TO H85 COLD FNT.
MAIN FCST CONCERNS TDAY ARE FOCUSED ON FIRE WX. FOCUS FOR TNGT THRU
SUN SHIFTS TO SHRA/TS CHCS ASSOCIATED WITH SLOWLY APRCHG UPR TROF/
COLD FNT.
TDAY...CWA WL REMAIN UNDER WARM SW FLOW AS COLD FNT TO THE W SLIDES
EWD THRU MN. ALTHOUGH H85 TEMPS ARE FCST TO AVG ABOUT A DEGREE LOWER
THAN YDAY...VERY DEEP MIXING SHOWN ON THE 00Z MPX RAOB SHOULD
SUPPORT MAX TEMPS NEARLY SIMILAR TO WHAT OCCURRED ON FRI PER
UPSTREAM OBSVD SFC HI TEMPS...WITH SOME PLACES OVER THE W HALF
SEEING THE MERCURY REACH 90. GOING FCST SHOWING THESE HIER TEMPS IN
THE DOWNSLOPE AREAS FM ONTONAGON TO BARAGA LOOK ON TRACK. AREAS OVER
THE E HALF SHOULD SEE SOME MODERATION OFF LK MI. SOME LK MODERATION
MAY SLIP A BIT FARTHER W INTO THE CNTRL IF FCST BACKING WINDS TO
MORE DUE S DRAGS THE LK MI MODERATION INTO THAT AREA. SEE FIRE WX
SECTION BLO FOR A DISCUSSION OF FIRE WX CONCERNS.
TNGT...WITH BLDG UPR RDG FCST OVER THE ERN GRT LKS...OPTED TO FOLLOW
THE SOMEWHAT SLOWER 12Z ECMWF/00Z CNDN MODELS FOR THE TIMING OF THE
COLD FNT...ESPECIALLY SINCE A SHRTWV LIFTING NEWD OUT OF THE ROCKIES
WL INDUCE A LOW PRES TO DVLP ON THIS BNDRY OVER THE PLAINS TDAY.
THIS LO IS FCST TO MOVE INTO MN BY 12Z SUN. THE 00Z NAM HAS TRENDED
IN THIS DIRECTION AS WELL. IN FACT...THE 12Z ECMWF/0Z CNDN MODELS
INDICATE THE BULK OF ANY PCPN WL BE ON THE COLD SIDE OF THE FNT
AND STAY W OF IWD THRU 12Z. THIS FCST IS REASONABLE CONSIDERING THE
DRYNESS OF THE WARM SECTOR AIRMASS AND FCST DEEP LYR QVECTOR CNVGC
BEING FOCUSED UNDER THE SHARPER DPVA ASSOCIATED WITH THE SHRTWV ON
THE COLD SIDE OF THE FNT IN MN EVEN AS LATE AS 12Z SUN. STEADY SW
FLOW IN THE WARM SECTOR SHOULD ONCE AGAIN LIMIT THE DIURNAL FALL OF
TEMP...SO MINS WL BE WELL ABV NORMAL AGAIN.
SUN...SINCE THE FAVORED 12Z ECMWF/00Z CNDN MODELS SHOW BULK OF DEEP
LYR QVECTOR CNVGC SHIFTING NEWD THRU WRN LK SUP TOWARD ONTARIO...
SUSPECT THE HIER POPS WL BE OVER THE NW CWA...WITH PCPN TENDING TO
DIMINISH AS THE FNT SHIFTS TO THE E INTO THE CENTRAL CWA BY LATE
AFTN. HOWEVER...DAYTIME HEATING MAY OFFSET THE LOSS OF BEST
DYNAMICS...ESPECIALLY SINCE THE CNDN MODEL SHOWS HIER H85 DWPTS UP
TO 12C SURGING NEWD RIGHT ALONG THE FNT. HOWEVER...THIS SOMEWHAT
HIER MSTR IS STILL RELATIVELY LO COMPARED TO H85 TEMPS FCST ARND
16C. SO THE LLVLS WL STILL BE RATHER DRY PER THE MODEL FCST
SDNGS...LIMITING DESTABILIZATION. OPTED TO GO WITH LIKELY POPS OVER
THE NW CWA...DIMINISHING TO CHC FARTHER TO THE E. RAISED FCST HI
TEMPS WELL INTO THE 80S OVER THE E AND CNTRL AWAY FM LK MI
MODERATION TO ACCOUNT FOR SLOWER ARRIVAL OF COLD FNT.
SUN NGT...EXPECT COLD FNT TO PUSH THRU THE REST OF THE CWA
ACCOMPANIED BY CHC POPS AS MAIN SHRTWV/SHARPEST DEEP LYR QVECTOR
CNVGC EXITS TO THE NE AND ANY HELP FM DIURNAL HEATING WANES. SINCE
GUIDANCE HINTS AT THE ARPCH OF A SECOND SHRTWV FM MN...MAINTAINED
THE CHC POPS HANGING WELL BACK BEHIND THE COLD FNT AS HINTED AT BY
00Z NAM/12Z ECWMF AND SHOWN IN PREVIOUS FCST DESPITE MID LVL DRYING
IN THE WAKE OF THE INITIAL DISTURBANCE. IF THIS TRAILING SHRTWV IS
WEAKER...THE DRYING BEHIND THE FIRST STRONGER SHRTWV MAY END THE
POPS FASTER THAN FCST AS FCST BY THE 00Z CNDN. THE ARRIVAL OF H85
TEMPS AOB 5C OVER THE W BY 12Z MON WL BRING A RETURN OF MORE
SEASONABLE TEMPS.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 508 AM EDT SAT MAY 19 2012
A SLOWLY TRANSITIONING WX PATTERN...WITH MUCH OF THE PERIOD
CONTINUING TO BE DOMINATED BY SOUTHERLY WINDS.
INITIALLY WE WILL HAVE THE EXITING COLD FRONT TO OUR EAST...AND HIGH
PRESSURE PUSHING IN FROM THE CENTRAL AND N PLAINS. AS A
RESULT...EXPECT TEMPS TO BE 10 TO 15 DEGREES COOLER THAN SUNDAY.
850MB TEMPS WILL BE 4-5C. WITH THE COOL TEMPS WILL COME DRY
AIR...WITH LOWER DEWPOINTS MONDAY AFTERNOON INTO THE MID 30S OVER
THE W HALF. WOULD NOT BE COMPLETELY SHOCKED TO SEE VALUES CLOSER TO
30F...WHICH WOULD GIVE RH VALUES NEAR 25 PERCENT.
THE SFC HIGH WILL BE DIRECTLY OVERHEAD TUESDAY MORNING...BEFORE
SLIDING E. EXPECT THE RETURN OF S WINDS...AND A LITTLE BETTER
MOISTURE. WE WILL SEE STRONGER SOUTHERLY WINDS RETURN BRIEFLY
WEDNESDAY AFTERNOON. ADJUSTED MAX TEMPS UP OVER THE TRADITIONAL
DOWNSLOPE AREAS NEAR LAKE SUPERIOR...WITH 850MB TEMPS RISING TO 11
TO 15C WITH THE COOLEST VALUES EAST.
WENT ABOVE CONSENSUS FOR HIGH TEMPS THURSDAY...ONCE AGAIN WITH A
MORE SIGNIFICANT INCREASE TO DOWNSLOPE AREAS. 850MB WINDS PEG OUT
BETWEEN 45 AND 60KTS...AND TEMPS JUMP UP TO 15-18C. THE 19/00Z GFS
IS ONE OF THE COOLEST SOLUTIONS.
WILL BE INTERESTING HOW THE END OF THE WORK WEEK PANS OUT...AND IF
THE FRONTAL BOUNDARY SETS UP AND STALLS OVER THE W CWA LIKE THE
19/00Z ECMWF...OR BLOWS THROUGH OUR AREA THURSDAY NIGHT BEFORE
STALLING OVER LOWER MI FRIDAY INTO SATURDAY. WILL NOT GET TOO FANCY
WITH THE FORECAST THAT FAR OUT...AND WILL KEEP THE SLIGHT CHANCE/LOW
CHANCE POPS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 135 AM EDT SAT MAY 19 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. EASTERN EDGE OF LLJ
CENTERED OVER NE MN WILL CREATE LLWS ON THE ORDER OF 30 TO 35 KTS
OVER THE LOWEST 1KFT TONIGHT...WITH THE MOST PROMINENT SHEAR AT IWD.
LLWS IS EXPECTED TO SUBSIDE AFTER DAYBREAK SUNDAY AS MIXING IS
ESTABLISHED...BUT THIS WILL ALLOW FOR GUSTY SOUTHERLY WINDS AT ALL
SITES...ESPECIALLY AT IWD AND SAW. MID-LEVEL CLOUD COVER THICKENS
LATE SATURDAY. SHOWERS AND POSSIBLY A THUNDERSTORM COULD BEGIN TO
AFFECT IWD BY THE END OF THE PERIOD AS A TROUGH/COLD FRONT APPROACH
THE AREA...THOUGH THEY WILL LIKELY REMAIN TO THE WEST UNTIL AFTER
06Z. LLWS ALSO REEMERGES AT SAW AS THE LLJ REDEVELOPS FURTHER EAST
THAN TONIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EDT SAT MAY 19 2012
WINDS SHOULD REMAIN BELOW 30KTS THROUGH THE PERIOD. LOW PRESSURE
STRETCHING FROM SOUTHWESTERN QUEBEC TO NEBRASKA WILL SHIFT
NORTHEASTWARD...FILLING SLIGHTLY AS IT CROSSES LAKE SUPERIOR SUNDAY
INTO SUNDAY EVENING. BEHIND THIS FEATURE...HIGH PRESSURE WILL BUILD
ACROSS THE UPPER GREAT LAKES MONDAY AND MONDAY NIGHT. EXPECT THE
HIGH TO SLOWLY EXIT NORTHEASTWARD THROUGH MID WEEK...IN RESPONSE TO
A STRONGER LOW NEARING FROM SOUTH CENTRAL CANADA THROUGH THE CENTRAL
PLAINS. EXPECT THE LOW TO OUR WEST TO MOVE OVER ONTARIO ON
THURSDAY...BEFORE EDGING ACROSS LAKE SUPERIOR THURSDAY NIGHT.
&&
.FIRE WEATHER...
ISSUED AT 508 AM EDT SAT MAY 19 2012
AFTER AN OVERNGT OF RELATIVELY POOR RH RECOVERY...EXPECT ANOTHER DAY
OF AT LEAST NEAR CRITICAL FIRE WX PARAMETERS. MAX TEMPS THIS AFTN
WILL BE SIMILAR TO WHAT WAS OBSVD YDAY...BUT DEEPER MIXING SHOWN
ESPECIALLY ON THE 00Z MPX RAOB MIGHT TAP INTO LOWER DEWPTS. IN
FACT...SFC DEWPTS WERE AS LO AS 35 TO 45 UPSTREAM YDAY AFTN IN WRN
WI/SRN MN. BLENDED MIXED DEWPT TOOL VALUES WITH THE PREVIOUS FCST
DEWPTS TO COME UP WITH READINGS DIPPING AS LO AS 43 OR SO. WITH
WINDS ALOFT TDAY ALSO NEARLY SIMILAR TO YDAY AND DEEP MIXING RELATED
TO DAYTIME HEATING... SUSTAINED WINDS AS HI AS 10 TO 20 MPH WITH
GUSTS TO 30 MPH AT THE MORE EXPOSED LOCATIONS ARE LIKELY. OPTED TO
ISSUE RFW FOR AN ARK FROM IWD/ONTONAGON TO BARAGA/MQT
COUNTIES...AREAS THAT SAW THE POOREST RH RECOVERY EARLY THIS MRNG
AND WHERE STRONGER WINDS/HIER DAYTIME HI TEMPS ARE MOST LIKELY. WL
ISSUE RFD FOR THE OTHER COUNTIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
RED FLAG WARNING FROM 1 PM EDT /NOON CDT/ THIS AFTERNOON TO 8 PM
EDT /7 PM CDT/ THIS EVENING FOR MIZ002-004-005-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...TK
MARINE...KF
FIRE WEATHER...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
429 AM CDT SAT MAY 19 2012
.DISCUSSION...
WATER VAPOR IMAGERY AND RUC H5 ANALYSIS SHOWS A RATHER EXPANSIVE
RIDGE IN PLACE THIS MORNING EAST OF THE MS RIVER...WITH A RATHER
COMPLEX TROUGH MOVING INTO THE HIGH PLAINS...WITH SEVERAL
SHORTWAVES EMBEDDED WITHIN IT. THE TWO PRIMARY ONES ARE CURRENTLY
OVER ERN SODAK AND MOVING FROM CO UP INTO SRN NEB. AT THE
SFC...A COUPLE OF AREAS OF LOW PRESSURE COULD BE FOUND OVER FAR SW
ONTARIO...WITH ANOTHER NEAR THE CO/NEB/KS BORDER. A COLD FRONT IS
ANALYZED BETWEEN THESE LOWS ACROSS THE ERN DAKOTAS.
FOR THE H5 PATTERN...THE RIDGING NOW MOVING ON TO THE HIGH PLAINS
WILL SLOWLY BEAT DOWN THE ERN RIDGE...WITH THE TROUGH CURRENTLY
COMING OUT OF CO WORKING ACROSS THE MPX CWA SUN INTO SUN EVENING.
FOR MON/TUE...RIDGING WILL BE BUILDING IN ACROSS CENTRAL NOAM AS A
SIGNIFICANT TROUGH DIGS INTO THE PAC NW. AS WE HEAD THROUGH THE
SECOND HALF OF NEXT WEEK...THIS PATTERN LOOKS BECOME QUITE
AMPLIFIED...AS VERY HIGH HEIGHTS SET UP INTO THE GREAT
LAKES...WITH A QUASI-STATIONARY DEEP TROUGH TAKING HOLD ACROSS
THE NRN ROCKIES...SETTING THE UPPER MIDWEST UP INTO A POTENTIAL
ACTIVE PATTERN.
AT THE SFC...THE COLD FRONT WILL WORK INTO WRN MN BY THIS
AFTERNOON...AND CLEAR THE MPX WI COUNTIES SUN AFTERNOON. THE LOW
CENTER CURRENTLY NEAR THE CO/NEB/KS WILL TRACK ACROSS SOUTH
CENTRAL MN INTO THE WRN TIP OF THE U.P. OF MICH SAT NIGHT/SUN.
HIGH PRESSURE WILL THEN SLIDE ACROSS THE AREA MON/TUE...BEFORE LEE
SIDE TROUGHING REESTABLISHES ITSELF OVER THE NRN HIGH PLAINS WED.
NEXT FRONT STILL ON TAP TO MOVE INTO MN WED NIGHT...AND WITH UPPER
RIDGE AMPLIFYING OVER THE GREAT LAKES THE LATTER HALF OF NEXT
WEEK...THIS FRONT STILL LOOKS TO STALL OUT THEN MEANDER AROUND THE
UPPER MS VALLEY INTO THE HOLIDAY WEEKEND.
THIS MORNING...STRONG WAA OUT AHEAD OF THE ERN SODAK SHORTWAVE
HAS RESULTED IN THE DEVELOPMENT OF AN AREA OF TSRA OVER WRN
MN...RADAR TRENDS MATCH WELL WITH THE IDEA THE RUC IS
SHOWING...WITH THIS WAA AND ASSOCIATED ACTIVITY BASICALLY GOING
DUE NORTH INTO NW MN. DO EXPECT CONDITIONS TO BE FAIRLY QUIET
THROUGH THE MORNING...WITH THE SODAK SHORTWAVE AND COLD FRONT
EXPECTED TO REMAIN WEST OF THE AREA. ONE CAVEAT IS THE LLJ AND
STRONG MOISTURE TRANSPORT IN PLACE ACROSS THE WEST. THIS MAY KEEP
SCT SHRA/TSRA ACTIVITY GOING THROUGH THE MORNING OUT WEST...BUT
DID NOT PLAY THIS IDEA UP TO MUCH IN THE GRIDS. INSTEAD...WAITED
UNTIL THE AFTERNOON TO REALLY GET POPS GOING. BY THEN THE COLD
FRONT WILL BE WORKING INTO WRN MN AS UPPER ENERGY BEGINS TO WORK
IN OVERHEAD. LOOKING AT HIRES REFLECTIVITY FORECASTS...SEEMS TO BE
GOOD AGREEMENT WITH STORMS INITIATING NEAR A RWF TO LONG PRAIRIE
LINE BETWEEN 20 AND 22Z...WITH ACTIVITY WORKING EAST TOWARD THE
I-35 CORRIDOR SHORTLY AFTER 00Z. FORECAST SOUNDINGS AGAIN SHOW
NICE INVERTED-V STRUCTURE THIS AFTERNOON...WITH MLCAPE AGAIN
PUSHING UP TO AROUND 1500 J/KG. IN ADDITION...UNLIKE
YESTERDAY...BULK SHEAR WILL BE IN THE 30-40 KT RANGE...INDICATING
SOME BETTER ORGANIZATION IN CONVECTION IS POSSIBLE. GIVEN LESS
FAVORABLE CONDITIONS MANAGED A FEW 60-70 MPH WIND GUSTS AND GOLF
BALL SIZE HAIL FRIDAY...DO NOT SEE WHY WE DO NOT HAVE A SIMILAR
THREAT FOR SEVERE WEATHER TODAY. IF ANYTHING...WOULD SUSPECT THE
WIND THREAT IS A BIT HIGHER AS BETTER SHEAR AND FAVORABLE
CONDITIONS FOR COLD POOL GENERATION MAY SUPPORT THE DEVELOPMENT OF
ORGANIZED LINE SEGMENTS. BESIDE THE PRECIP...SHOULD BE ANOTHER
WARM DAY...THOUGH NOT EXPECTING WIDESPREAD 90S LIKE FRIDAY. TWO
LIMITING FACTORS FOR HIGHS TODAY WILL BE MORE CLOUD COVER AND
ABOUT A 4 DEG C DROP IN H85 TEMPS. WITH THAT SAID...GUIDANCE HAS
HAD A PRETTY STRONG COLD BIAS IN THIS HEAT WAVE...SO CONTINUED TO
RUN WITH HIGHS A BIT HIGHER THAN WHAT MOST GUIDANCE WOULD SUGGEST.
FOR TONIGHT...WITH THE ARRIVAL OF THE UPPER TROUGH AND ATTENDANT
SFC LOW...WE CONTINUE TO SEE A STRONG SIGNAL FOR THE FORMATION OF
A DEFORMATION BAND OF PRECIP JUST TO THE WEST OF THE SFC LOW
TRACK. BLENDED THE ECMWF/GEM/SREF FOR PRECIP TONIGHT...WITH
HEAVIEST BAND OF PRECIP EXPECTED TO SETUP BETWEEN THE WRN TWIN
CITIES METRO AND MARSHALL/ALEXANDRIA. WITH THE SFC LOW COMING
THROUGH...THIS REALLY SLOWS DOWN THE PRECIP...AND CONTINUED TO
LEAN TIMING OF POPS ON SUN CLOSE TO THE ECMWF. THE ECMWF ALONG THE
NAM/SREF WOULD INDICATE SUNDAY BEING CLOUDY/RAINY FOR MOST OF THE
DAY SUNDAY ACROSS MOST OF THE MN MPX AREA...WITH HIGHS LIKELY NOT
LEAVING THE LOWER 60S. FURTHER EAST...THE COLD FRONT/LOW SHOULD BE
NEAR AN EAU/LADYSMITH LINE BY 18Z...SO SEVERE THREAT CERTAINLY
LOOKS BETTER EAST...THOUGH A MARGINAL TREAT FOR SEVERE WEATHER CAN
NOT BE RULED OUT IN THE FAR EAST.
MON THROUGH WED STILL LOOK DRY AS HIGH PRESSURE SLIDES ACROSS THE
AREA. BIGGEST THING TO WATCH WILL BE LOWS MONDAY MORNING. IF HIGHS
ONLY TOP OUT AROUND 60 IN CENTRAL MN...WE COULD SEE LOWS MONDAY
MORNING MAKE A RUN AT THE UPPER 30S AS HIGH PRESSURES MOVES IN AND
SKIES CLEAR OUT. OTHER THAN THAT...ITS OFF TO WAITING FOR THE NEXT
FRONT WEDNESDAY NIGHT. THE ONLY SIGNIFICANT CHANGE NOTED IN THE
MODELS WITH THIS FRONT IS THE 19.00 ECMWF BASICALLY HALTS ITS EWRD
PROGRESSION ACROSS WRN MN...WITH THE RAIN NOT MAKING IT TO ERN
AREAS. AT ANY RATE...CONTINUED TO MENTION HIGH CHANCE/LIKELY
POPS...ESPECIALLY WEST WED NIGHT. AFTER THAT...THE QUESTION
BECOMES WHERE DOES THE FRONT SET UP. WHERE EVER IT DOES SETUP...NORTH
OF THE BOUNDARY THROUGH THE WEEKEND IS LOOKING LIKE IT COULD BE A
BREEDING GROUND FOR SOME ACTIVE WEATHER...CERTAINLY SOMETHING TO
KEEP A CLOSE EYE ON AS WE HEAD INTO THE BUSY HOLIDAY WEEKEND.
&&
.AVIATION.../06Z TAF ISSUANCE/
OVER THE NEXT 48 HOURS...THUNDERSTORM CHANCES WILL BE THE MAIN
FORECAST CHALLENGE. ONGOING THUNDERSTORM ACTIVITY WAS ASSOCIATED
WITH AN UPPER LEVEL DISTURBANCE THAT HAD MOVE INTO MN LATE FRIDAY
AFTERNOON. THE THUNDERSTORMS CONTINUE TO DEVELOP ALONG A MOIST PLUME
THAT EXTENDS OVER NORTHERN MISSOURI INTO MINNESOTA. THE MAIN
THUNDERSTORM ACTIVITY WILL CONTINUE TO DEVELOP ALONG AND JUST AHEAD
OF NEARLY STATIONARY FRONTAL BOUNDARY OVER THE NORTHERN PLAINS.
EXPECT THUNDERSTORMS TO WANE DOWN OVERNIGHT OVER CENTRAL MN...AND
PERSIST OVER WESTERN MINNESOTA THROUGH SATURDAY MORNING. BASES OF
THE THUNDERSTORMS WILL BE AT OR ABOVE 4000 FEET AGL. BY MID
AFTERNOON SATURDAY...EXPECT MORE WIDESPREAD THUNDERSTORMS OVER MUCH
OF WESTERN MN...AND OVER THE EAST CENTRAL MN AND WESTERN
WISCONSIN...MAINLY AFTER MIDNIGHT TOMORROW NIGHT. WEATHER CONDITIONS
WILL REMAIN VFR FOR THE MOST PART...EXCEPT IN AND NEAR THE VICINITY
OF THUNDERSTORMS. SOUTH-SOUTHEAST WINDS INCREASING TO 20 TO 30 KNOTS
OVER EASTERN HALF OF THE FORECAST AREA SATURDAY. WINDS SHIFTING TO
THE NORTHWEST OVER WESTERN MN DURING THE AFTERNOON.
KMSP...VFR CONDITIONS PREVAILING THROUGH SATURDAY AFTERNOON/EVENING.
SCATTERED THUNDERSTORMS DEVELOPING DURING THE EVENING...WITH
THUNDERSTORMS BECOMING MORE LIKELY AROUND MIDNIGHT AND OVERNIGHT
SATURDAY NIGHT. SOUTH WINDS INCREASING TO 15 TO 25 KNOTS BY MID
MORNING SATURDAY.
OUTLOOK...
SAT NIGHT-SUN...SHRA/TSRA LIKELY WITH BRIEF MVFR/IFR POSSIBLE AS A
COLD FRONT PUSHES THROUGH.
MON-TUE...VFR.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/JVM
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1132 PM CDT FRI MAY 18 2012
.DISCUSSION...
MOSTLY SUNNY SKIES AND STRONG SOUTHERLY WINDS ACROSS THE UPPER
MIDWEST AHEAD OF A SURFACE TROUGH LOCATED OVER THE HIGH PLAINS
ALLOWED FOR NEAR RECORD WARMTH THIS AFTERNOON IN MINNESOTA AND
WISCONSIN. THE TROUGH OF LOW PRESSURE WILL GRADUALLY SLIDE
EASTWARD IN RESPONSE TO THE UPPER LEVEL FORCING...LEADING TO
SHOWERS AND THUNDERSTORMS CHANCES FOR THE WEEKEND. THERE WILL BE A
BRIEF DRY PERIOD MONDAY AND TUESDAY...WITH ON AND OFF THUNDERSTORM
CHANCES RETURNING FOR THE LATTER HALF OF THE PERIOD.
TODAY THROUGH SUNDAY...
LATEST WATERVAPOR IMAGERY COMBINED WITH 500MB HEIGHTS AND WINDS
SHOWED A BROAD LONGWAVE ACROSS THE GREAT BASIN...WITH UPPER LEVEL
DIVERGENCE DOWNSTREAM OVER THE HIGH PLAINS. THIS DIVERGENCE CAN BE
SEEN IDENTIFIED BY BOTH THE WIDESPREAD CLOUD FIELD AND SURFACE
PRESSURE TROUGH OVER THE HIGH PLAINS OF EASTERN MONTANA AND THE
WESTERN DAKOTAS. WITHIN THIS FLOW WERE A FEW FEATURES OF INTEREST.
THE FIRST OF WHICH IS A SHORTWAVE CROSSING THE MISSOURI RIVER
VALLEY INTO WESTERN IOWA. AN ADDITIONAL WAVE IS OFF THE BRITISH
COLUMBIA COAST...ALONG WITH A FEW EMBEDDED SHORTAVES IN THE
LONGWAVE THROUGH NEAR THE 4 CORNERS REGION. THE FIRST WAVE IS
ENOUGH TO SPARK A FEW ISOLATED SHOWERS ACROSS THE SOUTHWESTERN
CWA...AS INDICATED BY THE LAST FEW HRRR RUNS...AND CU FIELD. THE
MAIN CHANCE FOR PRECIP WILL BE LATER TOMORROW BEGINNING OUT WEST
AND SPREADING ACROSS THE THE REGION FOR SATURDAY NIGHT INTO
SUNDAY. LARGE SCALE ASCENT ASSOCIATED WITH THE UPPER LEVEL TROUGH
WILL BEGIN TO OVERTAKE THE REGION...WITH A FEW FOCUSED AREAS OF
PRECIP AS 3 DIFFERENT IDENTIFIABLE SHORTWAVES MOVE ACROSS THE
REGION. IS LOOKS LIKE THE BEST CHANCE FOR RAIN WILL BE SATURDAY
NIGHT INTO SUNDAY MORNING...AND HAVE INCREASED THE POPS AND QPF
DURING THIS TIME FRAME. FORECAST SOUNDINGS SHOW SOME DIRECTIONAL
SHEAR...BUT OVERALL THE WINDSPEEDS ARE LESS THAN 50KTS. THE SHEAR
INCREASES SATURDAY NIGHT AS THE LOW LEVEL JET STRENGTHENS...BUT
THE UPPER LEVEL WINDS REMAIN LESS THAN 50KTS. SOUNDINGS ALSO
INDICATE 1500 TO 2000 J/KG OF CAPE. SO BOTTOM LINE IS THE
POTENTIAL FOR SEVERE WEATHER DOES EXIST...BUT IT SHOULD BE
SPORADIC IN NATURE. IT LOOKS LIKE WE SHOULD SEE SOME GOOD SOAKING
RAINS WITH MULTIPLE ROUNDS OF PRECIP AS EACH WAVE MOVES
THROUGH
MONDAY THROUGH FRIDAY....DRY WEATHER IS EXPECTED AS HIGH PRESSURE
WILL BUILD ACROSS THE REGION FOR MONDAY AND TUESDAY. ON WEDNESDAY
A POWERFUL 120-140KT JET WILL CROSS THE WEST COAST AND MOVE
INLAND. AS IT DIGS OVER THE WESTCENTRAL US...IT WILL TAKE ON A
NEGATIVE TILT. THIS SETUP WILL DEVELOP A CYCLONE ACROSS THE HIGH
PLAINS...AND HAS THE POTENTIAL TO PRODUCE SOME SEVERE WEATHER FOR
THE LATTER HALF OF NEXT WEEK OVER THE GREAT PLAINS REGION. IT IS
TOO EARLY TO TELL THE EXACT TIMING AND PLACEMENT OF SEVERE
STORMS...BUT AS OF NOW CHOSE TO GO WITH A BLEND OF THE
GFS...ECMWF...AND PREVIOUS FORECAST...AND HAVE CHANCE POPS
THROUGHOUT THE EXTENDED PERIOD.
&&
.AVIATION.../06Z TAF ISSUANCE/
OVER THE NEXT 48 HOURS...THUNDERSTORM CHANCES WILL BE THE MAIN
FORECAST CHALLENGE. ONGOING THUNDERSTORM ACTIVITY WAS ASSOCIATED
WITH AN UPPER LEVEL DISTURBANCE THAT HAD MOVE INTO MN LATE FRIDAY
AFTERNOON. THE THUNDERSTORMS CONTINUE TO DEVELOP ALONG A MOIST PLUME
THAT EXTENDS OVER NORTHERN MISSOURI INTO MINNESOTA. THE MAIN
THUNDERSTORM ACTIVITY WILL CONTINUE TO DEVELOP ALONG AND JUST AHEAD
OF NEARLY STATIONARY FRONTAL BOUNDARY OVER THE NORTHERN PLAINS.
EXPECT THUNDERSTORMS TO WANE DOWN OVERNIGHT OVER CENTRAL MN...AND
PERSIST OVER WESTERN MINNESOTA THROUGH SATURDAY MORNING. BASES OF
THE THUNDERSTORMS WILL BE AT OR ABOVE 4000 FEET AGL. BY MID
AFTERNOON SATURDAY...EXPECT MORE WIDESPREAD THUNDERSTORMS OVER MUCH
OF WESTERN MN...AND OVER THE EAST CENTRAL MN AND WESTERN
WISCONSIN...MAINLY AFTER MIDNIGHT TOMORROW NIGHT. WEATHER CONDITIONS
WILL REMAIN VFR FOR THE MOST PART...EXCEPT IN AND NEAR THE VICINITY
OF THUNDERSTORMS. SOUTH-SOUTHEAST WINDS INCREASING TO 20 TO 30 KNOTS
OVER EASTERN HALF OF THE FORECAST AREA SATURDAY. WINDS SHIFTING TO
THE NORTHWEST OVER WESTERN MN DURING THE AFTERNOON.
KMSP...VFR CONDITIONS PREVAILING THROUGH SATURDAY AFTERNOON/EVENING.
SCATTERED THUNDERSTORMS DEVELOPING DURING THE EVENING...WITH
THUNDERSTORMS BECOMING MORE LIKELY AROUND MIDNIGHT AND OVERNIGHT
SATURDAY NIGHT. SOUTH WINDS INCREASING TO 15 TO 25 KNOTS BY MID
MORNING SATURDAY.
OUTLOOK...
SAT NIGHT-SUN...SHRA/TSRA LIKELY WITH BRIEF MVFR/IFR POSSIBLE AS A
COLD FRONT PUSHES THROUGH.
MON-TUE...VFR.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1216 AM CDT SAT MAY 19 2012
.AVIATION...
COLD FRONT WILL CONTINUE TO MOVE EAST ACROSS WESTERN AND CENTRAL
NEBRASKA THROUGH THE EARLY MORNING HOURS. THUNDERSTORMS WILL MOVE
OUT OF WESTERN NEBRASKA THROUGH 1909Z. ABUNDANT LOW LEVEL MOISTURE
BEHIND THE FRONT WILL BRING AREAS OF PATCHY DRIZZLE WITH MVFR
CEILINGS AFTER SUNRISE AND POSSIBLY SOME IFR CEILINGS AT BOTH KLBF
AND KVTN TAF SITES. STRONG NORTHWEST WINDS WILL CONTINUE BEHIND THE
FRONT THROUGH THE DAY. AS NEXT MID LEVEL WAVE PUSHES THROUGH THIS
AFTERNOON CEILINGS TO RISE WITH SHOWERS DEVELOPING. SHOWERS WILL END
THROUGH EARLY EVENING WITH WINDS SUBSIDING.
&&
.PREV DISCUSSION... /ISSUED 842 PM CDT FRI MAY 18 2012/
UPDATE...
UPDATED WIND FORECAST. WEATHER FORECAST ON TRACK. THUNDERSTORMS
NOT PUTTING OUT MUCH IN WAY OF RAIN BUT SOME WIND AND MOSTLY SMALL
HAIL. NUMEROUS LIGHTNING STRIKES WITH CLUSTER IN GARDEN GRANT AND
ARTHUR COUNTIES. LOOKS TO BE JUST ENOUGH TREAT TO DIMINISH FIRE
THREAT.
&&
.PREV DISCUSSION... /ISSUED 842 PM CDT FRI MAY 18 2012/
AVIATION...
STRONG STORMS MOVING ACROSS WESTERN NEBRASKA THIS EVENING. HAVE
INCLUDED TEMPO GROUP FOR KVTN THROUGH 4Z. NORTHWEST WINDS BUILDING
INTO THE NORTHWEST PANHANDLE. FROPA EXPECTED AT KVTN AROUND 1906Z
AND KLBF 1911Z. STRATUS AND CEILINGS LOWERING INTO THE IFR CATEGORIES
WITH DRIZZLE EXPECTED TO BUILD IN AFTER FROPA AND THEN LIGHT TO
MODERATE RAIN DEVELOPING THROUGH THE AFTERNOON WITH CEILINGS LIFTING
INTO MVFR.
PREV DISCUSSION... /ISSUED 330 PM CDT FRI MAY 18 2012/
DISCUSSION...
A POWERFUL UPPER LEVEL DISTURBANCE ACROSS COLO WILL MOVE SLOWLY
EAST TONIGHT AND SATURDAY PRODUCING SCATTERED TSTMS...MAINLY
ACROSS NORTH AND WEST PARTS OF THE FCST AREA WHICH WILL BE CLOSER
TO THE BEST DYNAMICS. SUPER ENSEMBLE FCST QPF SUGGESTS AROUND 1/4 INCH
OF RAIN NEAR NORTH PLATE AND CLOSE TO 3/4 OF AN INCH NEAR VALENTINE.
FOR THIS EVENING THE THREAT OF HIGH BASED TSTMS CAPABLE OF GUSTY
OR PERHAPS ISOLATED DAMAGING DOWNBURSTS WILL CONTINUE AS SFC RH IS
OPERATING BELOW 40 PERCENT. ONCE THE COLD FRONT SWEEPS SOUTH
LATER TONIGHT THE WIND THREAT SHOULD DIMINISH. THE ECM CONTINUES
TO BE SLOWER WITH COLD FRONT HOLDING IT UP SOME SATURDAY AFTERNOON
ACROSS THE ERN ZONES. THIS WAS INCORPORATED IN THE TEMP FORECAST
FOR HIGHS IN THE 70S EAST...BUT UPPER 50S TO AROUND 60 WEST.
THE UPPER LEVEL DISTURBANCE SHOULD CLEAR THE FCST AREA SATURDAY
NIGHT WITH STRONG HIGH PRESSURE BUILDING IN SUNDAY FOR NEARLY
CLEAR SKIES AND HIGHS IN THE 60S TO AROUND 70S. THE SFC HIGH WILL
MOVE OFF EAST QUICKLY MONDAY WITH SOUTHERLY RETURN FLOW DEVELOPING
AND A STRONG THERMAL RIDGE DEVELOPING ACROSS THE HIGH PLAINS AND
CNTL ROCKIES BY LATE MONDAY AFTERNOON. THIS THERMAL RIDGE SHOULD
MIGRATE EAST INTO THE NEB PANHANDLE TUESDAY AFTERNOON. MIX DOWN
TOOLS FROM 700 MB SUGGESTS HIGHS IN THE LOWER 90S. FOR NOW 80S
WILL OPERATE. ALL MODELS EXCEPT THE SLOWER AND VERY WARM GEM THEN
SWEEP A COLD FRONT THROUGH WEDNESDAY LOWERING TEMPS ABOUT 10
DEGREES. THE FRONT WILL THEN LIFT SLOWLY NORTH THROUGH KS AND
BECOME STATIONARY ACROSS SWRN NEB FRIDAY. ALL ALONG A DEEP UPPER
LEVEL TROF WILL DROP INTO THE WRN U.S. AND WINDS ALOFT WILL
BECOME SOUTHWEST AND INCREASE IN SPEED. SFC LOW PRESSURE WILL DEEPEN TO
BELOW 990 MB ACROSS WRN KS SUPPORTING WINDY CONDITIONS...SHARP
MOISTURE GRADIENTS AND A STRONG CAP...PERHAPS AS STRONG AS 12C
ACROSS SRN NEB. GIVEN THE FAST FLOW ALOFT AND FOCUS OF THE SFC
LOW...ISOLATED AND LOW-CHC POPS ARE IN PLACE LATE TUESDAY THROUGH
THURSDAY.
FIRE WEATHER...
A FAIRLY SHARP DRYLINE HAS FORMED NEAR WRAY AND HOLYOKE COLO THIS
AFTN WHERE RH IS RUNNING 11 TO 15 PERCENT. THE RUC SHOWS THIS
DRYLINE PUSHING EAST INTO SWRN NEB LATE THIS AFTERNOON AS THE SFC
LOW MOVES EAST TO NEAR BURLINGTON COLO. THE RED FLAG WARNING WILL
CONTINUE IN EFFECT THIS EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...POWER
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
158 AM EDT SAT MAY 19 2012
.SYNOPSIS...
STALLED LOW PRESSURE WILL CONTINUE TO BRUSH THE COAST...BRINGING
RAIN AND A FEW THUNDERSTORMS INTO THE MIDDLE OF NEXT WEEK. LOW
PRESSURE WILL FINALLY BEGIN TO MOVE NORTHEAST AND AWAY FROM THE AREA
WITH DRIER WEATHER FOR THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM FRIDAY...LATEST HRRR CONSOLIDATES THE BROAD SFC LOWS
OFF THE CAROLINA COASTS TO 1 INTENSE CONCENTRIC LOOKING LOW JUST
OFFSHORE FROM THE CAROLINA COASTS OVERNIGHT INTO SATURDAY. LATEST
NAM ALSO FAVORS THIS SOLUTION. SO WITH EGG ON MY FACE...HAVE UPDATED
THE ZONES WITH STRONGER NORTH TO NORTHEAST ACROSS THE FA WITH THE
ADDITION OF GUSTS UP TO AND OVER 20 KT ACROSS THE COASTAL COUNTIES.
BASED ON SURROUNDING 88DS INCLUDING OURS...THE CURRENT LOCATION OF
THE SFC LOW IS ROUGHLY 85 MILES SOUTHEAST OF BALD HEAD ISLAND. LIGHT
RAIN WILL CONTINUE TO TRACK WESTWARD AND PLAGUE THE COASTAL
COUNTIES...WITH THE MAIN CONVECTION STAYING NEAR THE SFC LOW ITSELF.
DO NOT ANTICIPATE ANY ONSHORE MOVEMENT OF THIS CONVECTION.
IN ADDITION TO UPPING THE WINDS...HAVE LOWERED TONIGHTS MINS BY
ATLEAST A CATEGORY. THIS BASED ON LATEST TEMP AND DEWPOINT TRENDS
AND A QUICK LOOK-SEE AT THE 00Z MODEL GUIDANCE.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 245 PM FRIDAY...BROAD UPPER LOW NOW CENTERED DIRECTLY OVER THE
COASTAL CAROLINAS WILL BE THE DRIVER FOR THE WEATHER IN THE SHORT
TERM. VARIOUS MID-RANGE GUIDANCE IN GOOD ACCORD AS TO THE CHARACTER
OF THE UPPER LOWS MOVEMENT...A SLOW SPIRAL OFFSHORE ON
SATURDAY...THEN A DRIFT TO THE NORTHWEST AND ONSHORE ON SUNDAY.
GUIDANCE A LITTLE LESS CLEAR AS TO THE PRECIPITATION CONSEQUENCES
AND SURFACE REFLECTIONS FOR THIS FEATURE...ESPECIALLY ON SATURDAY.
NAM IS THE WET SOLUTION WHILE ECMWF AND GFS KEEP THE EASTERN
CAROLINAS ON THE DRY SIDE ON SATURDAY. HAVE LEANED MORE TOWARDS THE
CONSENSUS DRYER SOLUTION FOR SATURDAY...WITH ISOLATED SHOWERS FOR
THE COASTAL COUNTIES AND MINIMAL QPF...YET WITH EXTENSIVE CLOUD
COVER. MORE AGREEMENT BETWEEN GUIDANCE AND HIGHER CONFIDENCE THAT
SUNDAY WILL BE THE WETTER DAY AS THE UPPER LOW AND ITS SURFACE
REFLECTION TRACK BACK NORTHWEST OVER LAND. OMEGA FIELDS SUGGEST WE
COULD ALSO SEE THUNDERSTORMS DEVELOP SUNDAY AFTERNOON AND EVENING AS
CORE OF UPPER LOW MOVES OVERHEAD.
EXTENSIVE CLOUDINESS ON BOTH DAYS AND A STEADY NORTH TO
NORTHEASTERLY FLOW THROUGH THE PERIOD WILL HELP KEEP DAYTIME
TEMPERATURES BELOW NORMAL OVER THE WEEKEND...WITH HIGHS IN THE LOWER
TO MID 70S ALONG THE COAST AND MID TO UPPER 70S INLAND.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 3 PM FRIDAY...MID TO UPPER LOW SITTING DIRECTLY OVERHEAD
EARLY MONDAY WILL LIFT OFF TO THE NORTHEAST MON NIGHT NIGHT INTO
TUES AS ANOTHER SHORTWAVE TROUGH DIGS DOWN OVER THE SOUTHEAST. THIS
TROUGH WILL PUSH A COLD FRONT THROUGH AREA TUES NIGHT INTO WED.
DEPENDING ON TIMING OF EXITING LOW...WE SHOULD SEE A PERIOD OF
SUBSIDENCE BEFORE NEXT SYSTEM COMES. AT THIS POINT IT LOOKS LIKE
TUES MORNING MAY BE DRY WITH A BRIEF PERIOD OF DEEPER NW FLOW AND
SUBSIDENCE ON BACK END OF LOW. PCP WATER DROPS FROM 1.8 INCHES DOWN
TO JUST BELOW 1.5 INCHES BEFORE INCREASING AGAIN IN CONVECTION AHEAD
OF COLD FRONT LATE TUES INTO EARLY WED. ONCE THIS FRONT CLEARS THE
COAST ON WEDNESDAY...IT LOOKS LIKE WEAK HIGH PRESSURE WILL SETTLE
OVER THE AREA THURS AND FRI WITH ONLY LOCALIZED SEA BREEZE
CONVECTION POSSIBLE. DEEP DRY NORTHERLY FLOW ALOFT WILL VEER AROUND
THURS THROUGH FRI WITH MOISTURE MAINLY CONFINED TO 5K FT AND BELOW
FROM THURS INTO NEXT WEEKEND.
WITH CLOUDS AND DEEP LAYER MOISTURE OVER AREA THE FIRST HALF OF THE
WEEK...AND H5 HEIGHTS AROUND 575 DEM...EXPECT TEMPS TO REMAIN BELOW
NORMAL UNTIL LOW LIFTS OFF AND FRONT PASSES BY ON WED. WARMING TREND
WILL BEGIN WED WITH TEMPS REACHING ABOVE NORMAL AS RIDGE BUILDS OVER
THE CAROLINAS FRI THROUGH NEXT WEEKEND.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 06Z...EXPECT VFR THROUGH VALID PERIOD...WITH EXCEPTION OF
POTENTIAL FOR LOW MVFR CEILINGS EARLY THIS MORNING AT KILM/KMYR/
KCRE.
A STALLED AREA OF LOW PRESSURE WILL CONTINUE TO SPIN OFF THE
CAROLINA COAST. RAIN WILL CONTINUE TO MOVE ONSHORE...WITH WIND GUSTS
NEAR 20 KT FOR THE COASTAL TERMINALS. THE INLAND TERMINALS WILL
REMAIN DRY WITH OVC MID LEVEL CLOUDS TENDING TO THIN THROUGH THE DAY.
THROUGHOUT THE DAY...MAY SEE SOME BREAKS IN THE CLOUDS...BUT OVERALL
EXPECT SCT/BKN MID TO HIGH CLOUDS TO LINGER AS LOW PRESSURE STAYS
JUST OFFSHORE. AFTER SUNSET...GUSTS WILL SUBSIDE ALLOWING FOR
NORTHEAST FLOW AOB 10 KTS TO PREVAIL.
EXTENDED OUTLOOK...MORNING STRATUS POSSIBLE THROUGH SUNDAY...MOSTLY
OVER THE NORTHERN HALF OF THE CWA
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 11 PM FRIDAY...STRONG SCA FOR ALL WATERS CONTINUES THROUGH
SATURDAY AFTERNOON. HAVE UPPED WINDS ACROSS ALL WATERS BASED ON THE
LATEST NAM/HRRR GUIDANCE WHICH ILLUSTRATE A CONSOLIDATED LOW. THE
KLTX 88D INDICATES THIS LOW NOW 85 MILES SOUTHEAST OF BALD HEAD
ISLAND. THE SFC PRESSURE PATTERN AND GRADIENT WILL YIELD NORTH TO
NORTHEAST WINDS 15 TO 25 KT WITH GUSTS UP TO 30 KT INTO SATURDAY
AFTERNOON. THE LATEST HRRR WIND OUTPUT NO LONGER LOOKS OVERDONE WITH
30 TO 40 KT SUSTAINED WINDS OFFSHORE AND CLOSER TO THE SFC LOW.
CORRESPONDING SEAS WILL RANGE FROM 4 TO 7 FT...UP TO 8 AND 9 FT
ACROSS THE OUTER WATERS OFF CAPE FEAR.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 245 PM FRIDAY...A GENERALLY NORTHERLY FLOW WILL PREVAIL
THROUGH THE PERIOD AS A TROUGH OF LOW PRESSURE LINGERS EAST OF THE
WATERS. LOW PRESSURE CENTERS DEVELOPING WITHIN THIS TROUGH WILL
TIGHTEN GRADIENTS ENOUGH TO BUMP WINDS UP INTO THE 15 TO 20 KT RANGE
THROUGH DAYTIME SUNDAY. WINDS WILL MODERATE LATER ON SUNDAY AS A LOW
PRESSURE SYSTEM MOVES OVERHEAD. SEAS WILL BE HIGHEST EARLIEST IN THE
PERIOD...WITH 6 FOOTERS LIKELY OVER THE OUTER FRINGES OF OUR WATERS.
WILL KEEP SMALL CRAFT ADVISORY HEADLINES FOR DAYTIME SATURDAY AS A
RESULT. OTHERWISE...SEE 3 TO 5 FT SEAS FOR MUCH OF THE SHORT
TERM...WITH SEAS SUBSIDING LATE ON SUNDAY AS WINDS MODERATE.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 3 PM FRIDAY...WINDS MAY BE A BIT TRICKY ON MONDAY AS LOW
PRESSURE SITS OVERHEAD. MAY RETROGRADE JUST ENOUGH TO THE WEST TO
PRODUCE A LIGHT S-SW FLOW. THIS LOW WILL LIFT OFF TO THE NORTHEAST
LATE MON INTO EARLY TUES WITH A BRIEF VEERING OF THE WINDS BEFORE
NEXT SYSTEM MOVES IN. THE WINDS SHOULD BACK AROUND THROUGH TUES AND
INCREASE SLIGHTLY OUT OF THE W-SW AS COLD FRONT APPROACHES FROM THE
NW. LOOKS LIKE THIS COLD FRONT WILL NOT MAKE A CLEAN SWEEP AND MAY
BECOME WASHED OUT ACROSS THE AREA WITH WEAK GRADIENT FLOW SETTING UP
BY THURS. WINDS WILL MOST LIKELY BE DRIVEN MORE BY LAND/SEA BREEZE
BY THURS. OVERALL EXPECT WINDS 10 KTS OR LESS THROUGH MOST OF THE
PERIOD...EXCEPT UP TO 15 KTS IN TIGHTENED GRADIENT FLOW LATE TUES
THROUGH EARLY WED. SEAS WILL RUN 2 TO 3 FT EXCEPT ON TUES WHEN THEY
INCREASE UP AROUND 4 FT IN OUTER WATERS TUES.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR AMZ250-252-
254-256.
&&
$$
NEAR TERM...DCH
SHORT TERM...REK
LONG TERM...RGZ
AVIATION...RJD/SGL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
145 AM EDT SAT MAY 19 2012
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND SOUTHWARD INTO THE CENTRAL CAROLINAS
THROUGH THE WEEKEND...WHILE A LOW PRESSURE SYSTEM STALLS OUT AND
MEANDERS JUST OFFSHORE THE CAROLINA COAST.
&&
.NEAR TERM /TODAY THROUGH SATURDAY NIGHT/...
AS OF 10 PM FRIDAY...
TONIGHT:
SURFACE HIGH PRESSURE CONTINUES TO BUILD/EXTEND INTO CENTRAL NC FROM
THE NORTHEAST THIS EVENING... WHILE A GENERALLY STACK LOW PRESSURE
SYSTEM IS LOCATED OFF THE COAST OF THE CAROLINAS. THIS SETUP AS
ALLOWED DRIER AIR IN THE LOW LEVELS OF THE ATMOSPHERE TO FILTER INTO
THE AREA IN MAINLY NORTH TO NORTHEASTERLY FLOW. MEANWHILE... MAINLY
HIGH LEVEL CLOUD COVER IS STREAMING INTO THE AREA ALOFT FROM SHOWERS
ANS STORMS THE OFFSHORE LOW PRESSURE SYSTEM. GIVEN THE RATHER DRY
AIR CONTINUING TO BUILD INTO THE AREA IN THE LOW LEVELS OF THE
ATMOSPHERE EXPECT DRY CONDITIONS FOR MOST IF NOT ALL OF THE CWA. THE
ONE EXCEPTION MAY BE FROM A FEW VERY LIGHT SHOWERS SKIRTING SOUTHERN
SAMPSON COUNTY THIS EVENING IN ASSOCIATED WITH THE OFFSHORE LOW.
HOWEVER... GIVEN THE LATEST RAP SOUNDINGS FOR SOUTHERN SAMPSON
COUNTIES STILL INDICATE A FAIRLY DRY SUB-CLOUD LAYER BELOW 750 MB
(WITH A DRYING TREND BELOW 750 MB EXPANDING THROUGHOUT THE EVENING)
WILL KEEP THE FORECAST DRY FOR THE ENTIRE AREA. THUS THE MAIN
FORECAST PROBLEM CONTINUES TO BE THE HIGH LEVEL CLOUD COVER AND THE
EFFECTS ON TEMPERATURES. HAVE INCREASED CLOUD COVER FROM THE
PREVIOUS FORECAST AND INCREASED LOW A DEGREE OR TWO... GIVEN CURRENT
OBSERVATIONAL DATA NAM AND GFS FORECAST SOUNDINGS. THIS YIELDS
GENERALLY PARTLY TO MOSTLY CLOUDY SKIES FOR A GOOD PART OF THE
NIGHT... WITH PERHAPS SOME MOSTLY CLEAR CONDITIONS ACROSS THE
WESTERN/NORTHWESTERN PIEDMONT. THUS... WILL GO WITH LOW TEMPS
GENERALLY IN THE LOWER TO MID 50S... WHICH IS NOW GENERALLY IN THE
MIDDLE OF THE STATISTICAL GUIDANCE RANGE.
SATURDAY AND SATURDAY NIGHT:
THE AFOREMENTIONED UPPER LEVEL LOW AND ATTENDANT SURFACE LOW ARE
PROGGED TO STALL JUST OFFSHORE THE CAROLINA COAST THROUGH 12Z SUNDAY
MORNING. MODEL GUIDANCE CONTINUES TO HAVE A DIFFICULT TIME WITH THE
PRECISE EVOLUTION OF THESE FEATURES...THOUGH NEITHER MODEL INDICATES
MORE THAN A TRACE OF PRECIP IN THE FAR EAST/SE COASTAL PLAIN THROUGH
SUNRISE SUNDAY MORNING. HOWEVER...THIS SYSTEM IS EXPECTED TO BECOME
MORE PROGRESSIVE DURING THE DAY SUNDAY...RETROGRADING ONSHORE INTO
EASTERN NC...AND IF THE SURFACE/UPPER LEVEL LOW RETROGRADE A BIT
SOONER THAN CURRENTLY PROGGED...LIGHT SHOWERS WOULD BE POSSIBLE EAST
OF THE I-95 CORRIDOR PRIOR TO SUNRISE SUNDAY MORNING. WITH THE ABOVE
IN MIND...WILL KEEP THE FCST DRY ON SATURDAY...AND WILL INDICATE A
SLIGHT CHANCE OF SHOWERS OR SPRINKLES IN THE COASTAL PLAIN AFTER
MIDNIGHT. THE AIRMASS ACROSS CENTRAL NC WILL VARY FROM VERY DRY IN
THE WESTERN PIEDMONT (0.50" PWAT AT GSO) TO MOIST IN THE COASTAL
PLAIN (PWAT 1.15" AT RWI) ON SATURDAY. EXPECT SUNNY OR MOSTLY SUNNY
SKIES IN THE WEST...AND PARTLY CLOUDY TO MOSTLY CLOUDY SKIES IN THE
EAST. EXPECT HIGHS ON SATURDAY TO BE SLIGHTLY WARMER THAN TODAY IN
THE WESTERN PIEDMONT (MID/UPPER 70S)...AND SIMILAR OR SLIGHTLY
COOLER THAN TODAY IN THE FAR EASTERN COASTAL PLAIN (LOWER 70S). LOWS
SAT NIGHT IN THE LOWER/MID 50S. -VINCENT
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 100 PM FRIDAY...
THE FORECAST WILL HINGE ON THE EVENTUAL FATE/EVOLUTION OF THE
MEANDERING CLOSED UPPER LOW AND ASSOCIATED LOW PRESSURE CENTER OFF
THE NORTH CAROLINA COAST. OVERALL...THE GUIDANCE ENVELOPE HAS
SHIFTED SLIGHTLY WESTWARD/INLAND FOR SUNDAY AND MONDAY...BUT THERE
REMAINS SIGNIFICANT SPREAD WITH THE TIMING AND HOW FAR INLAND THIS
SYSTEM WILL RETROGRADE.
IF CURRENT TRENDS HOLD UP...EXPECT THICKENING CLOUD COVER WITH
INCREASING RAIN CHANCES SUNDAY AFTERNOON/EVENING...AND CONTINUING
INTO THE DAY ON MONDAY AS THE EASTERLY ATLANTIC MARITIME FEED WILL
ADVECT HIGH PWATS ON THE ORDER 1.5-1.6"(2 SD ABOVE NORMAL)INLAND AS
THE CIRCULATION CENTER WOBBLES WESTWARD OVER THE FORECAST AREA.
EXPECT THAT WE WILL SEE A DIURNAL ENHANCEMENT IN POPS/CONVECTION...
SUNDAY AFTERNOON/EVENING AND AGAIN MONDAY AFTERNOON BEFORE THE
LOW BEGINS TO FINALLY TRANSLATE EASTWARD MONDAY EVENING/NIGHT WITH
THE APPROACH OF THE NORTHERN STREAM TROUGH FROM THE WEST. THERE
REMAINS TOO MUCH UNCERTAINTY AT THIS TIME TO DISCUSS IN DETAIL
ABOUT ANY SEVERE/HEAVY RAIN THREAT...BUT WILL NEED TO MONITOR
THE NEXT DAY OR TWO GIVEN RECENT HEAVY RAINS ACROSS CENTRAL AND
EASTERN NC. FOR THE SAME REASONS...WILL KEEP POPS IN THE SLIGHT TO
CHANCE CATEGORIES FOR NOW...WITH HIGHEST POPS IN THE EAST. WITH
TIME...BUT IF LATER MODEL RUNS START TO EXHIBIT BETTER CONTINUITY...
SUNDAY NIGHT AND INTO MONDAY COULD BE A WET PERIOD WITH LIKELY TO
CATEGORICAL POPS.
SEASONABLE TEMPERATURES SUNDAY THROUGH MONDAY...HIGHLY DEPENDENT ON
THE UPPER LOW AND ASSOCIATED RAIN CHANCES. GIVEN THE WESTWARD TREND
WITH THE LOW PRESSURE SYSTEM WILL NUDGE FORECAST HIGHS SUNDAY
AND MONDAY DOWN A BIT...HIGHS GENERALLY IN THE MID TO UPPER 70S.
LOWS 55 TO 60. -CBL
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 245 PM FRIDAY...
THERE ARE SOME PRETTY GLARING DIFFERENCES WITH THE TIMING AND
AMPLITUDE OF THE NEXT SHORTWAVE TROUGH AND ATTENDANT SURFACE FRONT
MOVING EAST THROUGH THE REGION DURING THE TUESDAY THROUGH
WEDNESDAY PERIOD. THE GFS IS UP TO ITS USUAL TRICKS/BIAS...
RACING THE OPEN WAVE TROUGH EASTWARD THROUGH THE AREA TUESDAY
EVENING/NIGHT...WHILE THE EC IS MORE SLOWER TO ADVANCE THE SYSTEM
EASTWARD...DEVELOPING INTO A CLOSED LOW INVOF OF THE OHIO/TN VALLEY
BEFORE FINALLY CROSSING THE AREA ON THURSDAY. UNTIL THERE IS BETTER
MODEL AGREEMENT WILL BROAD BRUSH SLIGHT TO SMALL CHANCE POPS ACROSS
THE AREA TUESDAY-WEDNESDAY WITH DRY CONDITIONS AFTERWORDS.
MODERATING TEMPERATURES IN THE LOW-LEVEL SWLY FLOW. HIGHS IN THE
LOWER TO MID 80S. LOWS IN THE 60S.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 140 AM SATURDAY...
HIGH CLOUDS ARE ABUNDANT OVER CENTRAL NC THIS MORNING AS A WEAK LOW
PRESSURE SYSTEM LINGERS OFF THE CAROLINA COAST. HOWEVER...
SIGNIFICANTLY DIRER AIR IS POURING IN FROM THE NORTHEAST AND
HELPING TO KEEP ANY STRATUS CONFINED TO THE COAST...THOUGH THE
STRATUS MAY WORK INLAND AND BE JUST EAST OF KFAY AND KRWI AROUND
12Z. VFR CONDITIONS ARE EXPECTED TO CONTINUE TODAY...WITH A
GENERALLY LIGHT NORTHEASTERLY WIND THAT MAY APPROACH 10KT IN THE
EAST. AS THE LOW PRESSURE OFFSHORE SLOWLY BEGINS TO STRENGTHEN
TONIGHT...LOW LEVEL MOISTURE IS FORECAST TO SURGE FURTHER WESTWARD.
BASED ON POOR AGREEMENT AMONG MODELS...THERE IS LOW CONFIDENCE IN
LOW CEILINGS REACHING KFAY AND KRWI BY 06Z SUNDAY MORNING...THOUGH
THE PROBABILITY OF MVFR AND IFR CEILINGS WILL BE INCREASING THROUGH
SUNDAY MORNING.
LOOKING AHEAD:
THERE WILL BE INCREASING CHANCES FOR SHOWERS AND LOW CEILINGS SUNDAY
AS A LOW PRESSURE SYSTEM DRIFTS WESTWARD ONSHORE SOMEWHERE OVER
NC/VA. THERE IS QUITE A BIT OF UNCERTAINTY REGARDING WHERE THE LOW
WILL TRACK AND EXACTLY WHEN POOR AVIATION CONDITIONS WILL BE MOST
WIDESPREAD...BUT CONDITIONS SHOULD GENERALLY BE WORSE OVER A MORE
PROLONGED PERIOD OVER EASTERN NC SUNDAY AND MONDAY. ANOTHER LOW
PRESSURE SYSTEM IS THEN FORECAST TO MOVE INTO THE AREA FROM THE WEST
ON TUESDAY...WITH CONTINUED UNSETTLED CONDITIONS POSSIBLE THROUGH
MIDWEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...BSD/VINCENT
SHORT TERM...CBL
LONG TERM...CBL
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
125 AM EDT SAT MAY 19 2012
.SYNOPSIS...
A WARM AND TRANQUIL WEEKEND IS IN STORE FOR THE AREA AS A DEEP
LAYERED RIDGE OF HIGH PRESSURE MOVES ACROSS OHIO INTO INTERIOR NEW
ENGLAND BY LATER ON SUNDAY. WEAK EASTERLY FLOW AT THE SURFACE WILL
HOLD DEEPER MOISTURE AT BAY...BUT HUMIDITIES WILL BE ON THE
INCREASE OVER WHAT HAS BEEN EXPERIENCED THE PREVIOUS FEW DAYS. A
WEAKENING WEATHER SYSTEM SHIFTING THROUGH THE WESTERN GREAT LAKES
SUNDAY NIGHT WILL SLOW AS IT MOVES INTO THE OHIO VALLEY...BRINGING
THE NEXT THREAT OF SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
DESPITE VERY WEAK NEAR-SURFACE WIND FLOW...MOISTURE IS INCREASING
FROM SOUTHEAST TO NORTHWEST ACROSS THE FORECAST AREA AT THIS TIME.
WITH THE MOSTLY CALM WINDS AND CLEAR SKIES...SOME FOG SEEMS LIKELY
IN PRONE AREAS...AND PATCHY REDUCED VISIBILITIES ARE POSSIBLE
ELSEWHERE AS WELL. ADDED SLIGHTLY MORE LOW-ELEVATION FOG THAN THE
PREVIOUS FORECAST...AND MADE SOME MINOR ADJUSTMENTS TO MIN TEMPS
AS WELL.
PREVIOUS DISCUSSION >
AMPLE SUNSHINE AGAIN TODAY WITH LOW DEWPOINTS /30S AND
40S/...THANKS TO DEEP LAYERED RIDGE OF HIGH PRESSURE OVER THE
AREA. 18.19Z RUC ANALYSIS INDICATED A CLOSED-CONTOUR 580DM
ANTICYCLONE OVER NRN INDIANA...ATOP A CLOSED-CONTOUR 576DM CYCLONE
JUST OFF THE SOUTH CAROLINA COAST. NOT OVER STRONG/IMPRESSIVE
SYSTEMS...BUT THIS REX BLOCK TYPE STRUCTURE WILL CONTINUE TO
DOMINATE OUR WEEKEND WEATHER PATTERN...WITH WEAK EASTERLY FLOW OUT
OF A SURFACE HIGH PRESSURE SYSTEM IN NEW ENGLAND /RATHER BAGGY
PRESSURE GRADIENT/ CONTINUING TO HOLD DEEPER BOUNDARY LAYER
MOISTURE /60S DEWPOINTS/ WELL SOUTH AND WEST OF THE AREA.
IN THE UPCOMING 12-15 HOURS...EXPECT VERY LITTLE SYNOPTIC SCALE
CHANGE AS THE MID-LEVEL HIGH DRIFTS THROUGH NRN OHIO AND
STRENGTHENS SLIGHTLY WHILE THE LOW OVER THE WRN ATL ELONGATES SOME
BEGINS SPLITTING INTO TWO DISTINCT CYCLONIC CIRCULATION
CENTERS...ONE IN ERN GA AND THE OTHER OFF THE NC COAST.
VERY WEAK SFC FLOW WILL QUICKLY GO CALM THIS EVENING UNDER RAPIDLY
STRENGTHENING INVERSION AND DECOUPLING OF THE SHALLOWING BOUNDARY
LAYER. THIS SHOULD FOSTER A RAPID EVENING TEMP DROP WITH CLEAR
SKIES. RAN A GENERAL BLEND OF THE PREVIOUS FORECAST AND 12Z
ECMWF/GFS/NAM MOS...THOUGH TWEAKED A TOUCH DOWNWARD IN THE COOL
SPOTS GIVEN IDEAL RADIATIONAL COOLING REGIME. ALSO FOGGED UP THE
OHIO AND ADJACENT RIVER VALLEYS LATER IN THE NIGHT...AS BOUNDARY
LAYER MOISTURE FROM KY WILL BE SEEPING NWRD OVERNIGHT AS MINOR SLY
COMPONENT TO THE GENERAL EASTERLY FLOW WILL ALLOW AN INCREASE IN
LLVL MOISTURE. WOULD NOT BE SURPRISED IS FOG BECOMES A LITTLE MORE
WIDESPREAD THAN FORECAST ESP OVER NRN KY/SRN OH/SERN IND.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
VERY LITTLE CHANGE TO THE PATTERN ALOFT ON SATURDAY...THOUGH THE
LOW LEVELS WILL BEGIN TO UNDERGO SOME MOISTURE ADVECTION...ESPECIALLY
ACROSS SRN/SWRN FORECAST AREA. 18.12Z WRF/GFS INDICATE LOWEST 1KM
SPECIFIC HUMIDITIES DOUBLING IN COMPARISON TO FRIDAY...SO BROUGHT
DEWPOINTS UP A BIT IN THE SOUTH/SOUTHWEST...PERHAPS NOT ENOUGH.
FEEL 18.12Z NAM-WRF SFC DWPTS ABOUT 10F TOO HIGH AS HAS BEEN A
PROBLEM THIS SPRING...SO DISCOUNTING THE RATHER STRONG INSTBY THAT
DEVELOPS UNDERNEATH THE MID LEVEL RIDGE SATURDAY AFTERNOON. EVEN
SO...ADDITIONAL MOISTURE AND A FAVORABLE LAPSE RATE WILL NO DOUBT
YIELD SOME DEEPER CUMULUS ACROSS THE SOUTH/SOUTHWEST...BUT THINK
NIL FORCING AND CONTINUED RISING HEIGHTS WILL MITIGATE A NEED FOR
A RAIN CHANCE AT THIS TIME. A WARM DAY...AND MOS SHOULD PERFORM
WELL IN THIS RATHER PREDICTABLE REGIME...SO AGAIN BLENDED PREVIOUS
FORECAST WITH MOST RECENT VALUES. SPOT CHECK OF LOW LEVEL
THICKNESS CONSIDERATIONS AND MIXING TO 850-825MB /DESPITE VERY
WEAK FLOW/ SUGGESTS WIDESPREAD LOWER TO MIDDLE 80S...VERY MUCH IN
LINE WITH THE BLEND.
LIKELY A REPEAT SCENARIO SATURDAY NIGHT WITH VALLEY FOG...AND
LOWS IN THE 50S.
SUNDAY IS A CARBON-COPY OF SATURDAY. DISTINCT CIRCULATION CENTERS
ATTENDANT TO THE SOUTHEAST CONUS TROUGH RECOMBINE OVER THE OUTER
BANKS OF NC WHILE THE MID LEVEL ANTICYCLONE CONTINUES TO DEEPEN TO
585DM OVER INTERIOR NEW ENGLAND. THIS WILL REINFORCE A LOW LEVEL
EASTERLY TRAJECTORY...THUS DON/T EXPECT MUCH /IF ANY/ DEWPOINT
RISE ON SUNDAY...AND TEMPERATURES SHOULD HOLD VERY SIMILAR TO
SATURDAY/S READINGS. PROBABLY A THICKER CIRRUS SHIELD PER BUFR
SOUNDINGS...BUT THAT WOULD BE ABOUT THE EXTENT OF SENSIBLE
WEATHER.
SUNDAY NIGHT BEGINS TO SEE SOME CHANGE AS A TROUGH OF LOW PRESSURE
/DAMPENING OUT AND SLOWING AS IT ENCOUNTERS THE BLOCKY FLOW ALONG THE
EAST COAST/ APPROACHES THE GREAT LAKES. HAVE KEPT THE NIGHTTIME
DRY AT THIS POINT AS 18.12Z GUIDANCE WAFFLING ON WEAK/MID LEVEL-
BASED SHOWERS AND STORM PLACEMENT AS FORCING SLOWLY INCREASES
LATER IN THE NIGHT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
PERIOD OF DRY WEATHER MAY COME TO AN END MONDAY AS MOISTURE AND
INSTABILITY INCREASE AHEAD OF AN UPPER TROUGH. WITH THE ECMWF AND
GFS COMING INTO FAIR AGREEMENT...KEPT A CHANCE OF THUNDERSTORMS FOR
MONDAY...MAINLY IN WESTERN COUNTIES THAT WILL BE AFFECTED MORE BY
SURFACE CONVERGENCE AND COOLER AIR ALOFT.
STAYED CLOSE TO ECMWF SOLUTION FOR TUESDAY SINCE IT CONTINUES TO
SHOW A CLOSED UPPER LOW FORMING AS OPPOSED TO THE FASTER OPEN WAVE
DEPICTED ON THE GFS. AS THE UPPER LOW FORMS NEAR CVG...THERE WILL BE
A GOOD CHANCE FOR THUNDERSTORMS UNDER A COOL POOL ALOFT COUPLED WITH
DEEP MOISTURE ADVECTION FROM THE SOUTH.
THUNDERSTORMS CHANCES WILL DIMINISH ON WEDNESDAY AS THE CLOSED UPPER
LOW SLIPS EAST ALLOWING DRIER AND MORE STABLE AIR TO WORK IN. THE
DRY CONDITIONS ARE EXPECTED TO CONTINUE ON THURSDAY AND FRIDAY WHEN
RIDGING ALOFT IS FORECAST TO MOVE BACK IN.
HIGH TEMPERATURES WILL BE MAINLY IN THE 80S MONDAY ON THE EAST SIDE
OF THE UPPER TROUGH. COOLER READINGS IN THE 70S ARE FORECAST AS THE
CLOSED LOW MAKES ITS WAY ACROSS THE AREA WITH ASSOCIATED CLOUD COVER
AND COLD ADVECTION. LOOK FOR A REBOUND TO THE 80S BY FRIDAY AS
SUNSHINE AND WARM ADVECTION RETURN.
&&
.AVIATION /05Z SATURDAY THROUGH WEDNESDAY/...
HIGH PRESSURE WILL KEEP DRY CONDITIONS ACROSS THE TAF SITES
THROUGH THE TAF PERIOD. VFR CONDITIONS WILL START OUT THE TAF
PERIOD HOWEVER SOME FOG WILL BE POSSIBLE AT KLUK...KCVG...AND KILN
OVERNIGHT. VFR CONDITIONS WILL RETURN TO THE TAF SITES DURING THE
DAY ON SATURDAY. CU WILL DEVELOP ACROSS THE AREA DURING MAINLY THE
AFTERNOON HOURS. WINDS WILL BE LESS THAN 10 KNOTS.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE MONDAY AND TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...BINAU
NEAR TERM...BINAU/HATZOS
SHORT TERM...BINAU
LONG TERM...CONIGLIO
AVIATION...NOVAK
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1125 PM CDT FRI MAY 18 2012
.AVIATION...
CONCERNS REMAIN TRAJECTORY OF MVFR STRATUS OVERNIGHT. HAVE
CONTINUED WITH THE RUC OPS/BAK40 SOUNDINGS AND NAM12 BOUNDARY
LAYER RH/BUFR SOUNDINGS WITH CIGS REMAINING JUST SOUTH THROUGH
WEST OF THE METROPLEX...THOUGH SCATTERED STRATO-CU MAY BE AROUND
RIGHT AFTER SUNRISE SATURDAY MORNING.
FOR WACO...MAINTAINED A TREND OF MVFR CIGS BETWEEN 11Z AND
15Z...THEN VFR AFTERWARD.
CONFIDENCE ON STRATUS TRAJECTORY IS NOT HIGH WITH LITTLE OR NO
DEVELOPMENT AS OF 05Z UPSTREAM ALONG THE TX COASTAL BEND/LOWER TX
COAST/OR NORTHERN MEXICO YET.
OTHERWISE...SSE WINDS AROUND 10 KTS...WILL BECOME SLY NEAR 15 KTS
BY LATE MORNING SATURDAY WITH GUSTS TO OR IN EXCESS OF 25 KTS
POSSIBLE WITH VFR CONDITIONS. LOOK FOR GUSTS TO SETTLE DOWN BY 00Z
SUNDAY AS BOUNDARY LAYER SEMI DECOUPLES.
05/
&&
.UPDATE...
GRIDS IN EXCELLENT SHAPE. NO UPDATE NEEDED.
25
&&
.PREV DISCUSSION... /ISSUED 326 PM CDT FRI MAY 18 2012/
LOW LEVEL WARM AIR ADVECTION WILL CONTINUE ACROSS THE REGION
TONIGHT THROUGH SUNDAY AS SURFACE LOW PRESSURE MOVES EASTWARD
FROM THE HIGH PLAINS. A RELATIVELY TIGHT PRESSURE GRADIENT WILL
RESULT IN BREEZY CONDITIONS THIS EVENING AND AGAIN ON SATURDAY.
AS THE SURFACE LOW MOVES EAST...SURFACE HIGH PRESSURE WILL BUILD
SOUTHWARD AND A COLD FRONT WILL APPROACH THE RED RIVER SUNDAY
MORNING. A FEW SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE COLD
FRONT...WITH THE BEST CHANCE OF STORMS NORTH OF THE RED RIVER.
THE FRONT SHOULD STALL DURING THE DAYTIME HOURS DUE TO VIGOROUS
MIXING ALONG THE LEADING EDGE...BUT WILL BEGIN TO MOVE SOUTH
AGAIN SUNDAY NIGHT/MONDAY. THE BEST PUSH BEHIND THE FRONT WILL BE
EAST OF THE REGION. THEREFORE...THE FRONT WILL MOST LIKELY STALL
ACROSS THE NORTHERN PORTIONS OF NORTH TEXAS MONDAY AFTERNOON. THE
ATMOSPHERE WILL BE UNSTABLE ENOUGH FOR SCATTERED SHOWERS AND
THUNDERSTORMS ALONG AND NORTH OF THE FRONT. SEVERE STORMS ARE
UNLIKELY DUE TO A WEAK SHEAR PROFILE. THE COLD FRONT WILL LIFT
QUICKLY NORTH OF THE REGION MONDAY NIGHT/TUESDAY AS THE UPPER
PATTERN BECOMES MORE ZONAL AND RESULTS IN A THE DEVELOPMENT OF A
LEE TROUGH. THIS PATTERN WILL KEEP NORTH TEXAS WARM AND HUMID
NEXT WEEK WITH HIGHS MAINLY IN THE UPPER 80S AND LOW 90S AND LOWS
GENERALLY IN THE 60S.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 65 87 65 86 65 / 0 5 5 10 10
WACO, TX 65 87 65 87 66 / 0 5 5 5 10
PARIS, TX 62 85 64 86 66 / 0 5 5 10 10
DENTON, TX 63 87 64 85 64 / 0 5 5 10 10
MCKINNEY, TX 61 87 64 86 65 / 0 5 5 10 10
DALLAS, TX 64 87 64 88 65 / 0 5 5 10 10
TERRELL, TX 63 88 63 86 64 / 0 5 5 10 10
CORSICANA, TX 64 88 65 87 67 / 0 5 5 5 10
TEMPLE, TX 64 86 64 86 65 / 0 5 5 5 10
MINERAL WELLS, TX 63 89 65 86 63 / 0 5 5 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
243 AM CDT SAT MAY 19 2012
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
243 AM CDT SAT MAY 19 2012
THE MAIN FOCUS THROUGH THE WEEKEND AND EARLY NEXT WEEK IS WITH THE
SHOWER/THUNDERSTORM CHANCES TONIGHT INTO SUNDAY ALONG WITH
TEMPERATURES AND WINDS FOR TODAY.
AN ELONGATED TROUGH OF SURFACE LOW PRESSURE CONTINUES TO DRIFT
EAST ACROSS THE CENTRAL PLAINS WITH MUCH OF THE UPPER MISSISSIPPI
RIVER VALLEY IN THE WARM SECTOR OF THIS SYSTEM. THE MAIN LOW
IS GETTING ORGANIZED ACROSS EASTERN COLORADO/SOUTHWEST NEBRASKA
WHICH IS AHEAD OF A DIGGING MID LEVEL TROUGH STILL OUT IN THE
ROCKIES. IN THE NEAR TERM...JUST DEALING WITH SOME HIGH LEVEL
CLOUD COVER AND A DECOUPLED ATMOSPHERE. STORMS IN CENTRAL TO
NORTHERN MINNESOTA WILL CONTINUE TO LIFT TO THE NORTH AHEAD OF A
MID LEVEL SHORTWAVE TROF WHICH WILL TAKE A SIMILAR PATH. THE
SOUTHERN EXTENT OF THIS TROUGH WAS VISIBLE ACROSS IOWA VIA IR
SATELLITE EARLIER...BUT HAS SINCE DISSIPATED.
THREE MAIN FORECAST ISSUES FOR TODAY INCLUDE HOW WARM
TEMPERATURES WILL GET...HOW STRONG WILL THE WINDS BECOME...AND
WHEN WILL CONVECTION MOVE INTO THE REGION.
TEMPERATURE-WISE...THE 19.00Z NAM/GFS/ECMWF/GEM DO NOT SHOW MUCH
IN THE WAY OF THE AIR MASS MODERATING ACROSS THE REGION TODAY WITH
850MB TEMPERATURES LINGERING AROUND +16C. YESTERDAY...THESE 850MB
TEMPERATURES WERE A BIT HIGHER IN WESTERN MINNESOTA AND IOWA AT
ABOUT +20C TO +22C. WITH FULL MIXING IT BROUGHT SURFACE
TEMPERATURES INTO THE MID 90S WHILE DEW POINTS ACTUALLY HELD ON
INTO THE LOW 50S. WITH A SIMILAR DAY OF FULL MIXING LOCALLY...EXPECT
THAT TEMPERATURES SHOULD BE PRETTY CLOSE TO WHERE WE ENDED UP
TODAY WITH MOST LOCATIONS IN THE UPPER 80S AND SOME SPOTS GETTING
INTO THE 90S.
AS FOR THE WINDS...A TIGHT SURFACE PRESSURE GRADIENT WILL REMAIN
IN PLACE THROUGH THIS AFTERNOON DUE TO THE DEEPENING SURFACE LOW
IN THE SOUTHERN PLAINS AND RIDGE OFF TO THE EAST. 19.00Z NAM
BUFKIT SOUNDINGS FROM RST SHOW MIXING FROM THE SURFACE ON UP TO
AROUND 800MB WITH WINDS OF ABOUT 40KTS AT THE BASE OF THE
INVERSION AROUND 800MB. MOMENTUM TRANSFER SHOWS THAT THE GUSTS
SHOULD BE AROUND 30-35KTS WITH LESSER AMOUNTS AS YOU MOVE INTO THE
LOWER TERRAIN TO THE EAST. CONSIDERED A WIND ADVISORY FOR
PORTIONS OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA FOR TODAY...BUT
CONFIDENCE WAS NOT HIGH ENOUGH TO DO SO GIVEN THAT THE ADVISORY
CRITERIA GUSTS WOULD BE FAIRLY LOCALIZED AND NOT WIDESPREAD/LONG
LASTING.
PRECIPITATION CHANCES WILL BE ON THE INCREASE AS THE TROUGH/COLD
FRONT INCH EASTWARD THIS EVENING AND OVERNIGHT ACROSS EASTERN
MINNESOTA...CENTRAL IOWA AND NORTHWEST WISCONSIN. MUCH OF THE
FOCUS FOR LIFT WILL COME AS A MID LEVEL TROUGH TRACKS NORTHEAST
THROUGH THE SOUTHWESTERLY FLOW. THE 19.00Z NAM/GFS/GEM SHOW THIS
MAIN MID LEVEL TROUGH LIFTING NORTHEAST ALONG THE BOUNDARY EARLY
SUNDAY MORNING WITH THE SURFACE COLD FRONT MOVING THROUGH IN THE
AFTERNOON. THERE IS SOME CONCERN FOR SEVERE WEATHER ON SUNDAY DUE
TO A MID LEVEL JET STREAK MOVING THROUGH WITH THE TROUGH AND
BUILDING INSTABILITY AHEAD OF THE SURFACE COLD FRONT/LOW. THE
TIMING OF THE FRONT AND/OR PRE-FRONTAL SURFACE TROUGH IS IDEAL FOR
MAXIMIZING PEAK HEATING...BUT IT APPEARS THAT THE BETTER DEEP WIND
SHEAR COMES THROUGH IN THE MORNING AS THE TROUGH MOVES THROUGH
WITH THE 40-50KT JET STREAK NORTH OF LAKE SUPERIOR BY AFTERNOON.
IF THE SOUTHERN PORTION OF THE MID LEVEL JET STREAK CAN LINGER
INTO THE AFTERNOON...IT MAY PROVIDE SOME BETTER 0-6KM SHEAR TO
WORK WITH SOME SURFACE BASED INSTABILITY OF 1000-2000J/KG TO
PRODUCE SOME ORGANIZED CONVECTION. THESE STORMS/SHOWERS SHOULD
EXIT THE REGION SUNDAY NIGHT WITH HIGH PRESSURE AND COOLER AIR
DROPPING DOWN BEHIND THE SYSTEM.
.LONG TERM...TUESDAY THROUGH FRIDAY
243 AM CDT SAT MAY 19 2012
QUIET START TO THE EXTENDED PERIOD AS A RIDGE OF HIGH PRESSURE
MOVES ACROSS THE REGION OVER THE MIDDLE OF THE WEEK. THE NEXT
FEATURE TO POSSIBLY BRING SOME PRECIPITATION TO THE REGION COMES
IN ON WEDNESDAY AFTERNOON IS A COLD FRONT THAT WILL DROP INTO
MINNESOTA. SOME FAIRLY SIGNIFICANT DIFFERENCES CROP UP BETWEEN THE
19.00Z GFS/ECMWF/GEM WITH THIS FRONT AND HOW MUCH PROGRESS IT
MAKES TO THE EAST GOING INTO THE LATER PORTION OF THE WEEK. THE
GFS HAS BEEN PRETTY CONSISTENT WITH SWINGING THE COLD FRONT
THROUGH THE REGION AND THEN SETTING IT UP TO THE SOUTH WITH COOL
AIR MOVING IN BEHIND IT. MEANWHILE...THE ECMWF HAS BEEN BOUNCING
BACK AND FORTH WITH WHETHER THE FRONT EVEN MAKES IT INTO THE
REGION ON THURSDAY. OVER THE PAST TWO DAYS...THE 12Z RUNS HAVE
BEEN TAKING THE FRONT FURTHER EAST AND BRINGING PRECIPITATION IN
WHILE THE 00Z RUNS HAVE KEPT US MAINLY DRY. THE GEM DOES SOMETHING
SIMILAR TO THE 00Z ECMWF RUNS WITH KEEPING THE FRONT OFF TO THE
WEST AS WELL. WHILE THE 19.00Z GFS APPEARS TO BE AN OUTLIER AT
THIS POINT...CAN NOT RULE OUT THE POSSIBILITY OF CONVECTION
GETTING INTO THE REGION AND HAVE LEFT SOME CHANCES OUT IN THE
EXTENDED PERIOD THOUGH CONFIDENCE IS NOT VERY HIGH WITH THEM.
THE MOST NOTEWORTHY FEATURE IN THE EXTENDED PERIOD IS WITH THE
HEAT WAVE THAT THE 19.00Z ECMWF IS FORECASTING FROM THURSDAY
ONWARD INTO MEMORIAL DAY WEEKEND AS THE FRONT STALLS AND IS FORCED
UP TO THE NORTH AS SOUTHERLY LOW LEVEL FLOW BRINGS WARM AIR BACK
INTO THE REGION. THE 19.00Z ECMWF IS FORECASTING HIGH TEMPERATURES
OF 85-95F FROM THURSDAY THROUGH MONDAY WHILE THE 19.00Z GFS
REMAINS MUCH COOLER. AS PREVIOUSLY MENTIONED...CONFIDENCE IS NOT
HIGH WITH WHAT MODEL IS THE TREND SETTER...BUT IF THE ECMWF IS THE
TREND THEN WE ARE WAY UNDER DOING TEMPERATURES GOING INTO NEXT
WEEKEND.
&&
.AVIATION...THROUGH 06Z SUNDAY
1145 PM CDT FRI MAY 18 2012
SOUTHERLY FLOW WILL CONTINUE AT THE TAF SITES THROUGH THE PERIOD.
VFR CONDITIONS ARE EXPECTED THOUGH 06Z SATURDAY. WINDS HAVE
DECOUPLED AT KLSE WITH SURFACE WINDS AROUND 10 KNOTS. KARX VAD
WIND PROFILER SHOWS 2000 FOOT WINDS AT 40 KNOTS AND BOTH THE
19.02Z RAP AND 19.00Z NAM BUFKIT SOUNDINGS SHOWING 35 TO 40 KNOT
WINDS CONTINUING JUST OFF THE SURFACE. THUS DID INCLUDE LLWS AT
THE KLSE SITE THROUGH 14Z. LOW LEVEL WINDS AT KRST WILL BE MARGINAL
FOR LLWS AND WILL NOT INCLUDE. WINDS WILL PICK UP ONCE AGAIN
SATURDAY WITH SOME GUSTS TO 30 KNOTS AT KRST AND NEAR 25 KNOTS AT
KLSE. A COLD FRONT WILL THEN MOVE INTO WESTERN MINNESOTA DURING
THE AFTERNOON AND EVENING HOURS. DID MENTION VCSH AT KRST AFTER
01Z AS FRONT APPROACHES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
243 AM CDT SAT MAY 19 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1146 PM CDT FRI MAY 18 2012
.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
343 PM CDT FRI MAY 18 2012
AT 3 PM...A TIGHT SURFACE PRESSURE GRADIENT HAS DEVELOPED BETWEEN
A HIGH PRESSURE SYSTEM OVER NEW ENGLAND AND A LOW PRESSURE SYSTEM
OVER SOUTH DAKOTA. THIS GRADIENT WAS PRODUCING SUSTAINED WINDS IN
THE 15 TO 25 MPH RANGE AND WIND GUSTS AROUND 35 MPH. THE HIGHEST
WIND GUSTS WERE 37 MPH AT THE ROCHESTER ASOS AND NEAR DEXTER
MINNESOTA. THE COMBINATION OF SOUTHERLY WINDS AND ABUNDANT SUNSHINE
HAS ALLOWED TEMPERATURES TO CLIMB TO AROUND 90 ACROSS NORTHEAST
IOWA AND SOUTHEAST MINNESOTA...AND FROM THE MID TO LOWER 90S ACROSS
WESTERN WISCONSIN. THIS MAKES IT THE WARMEST DAY OF THIS YEAR IN
MOST LOCATIONS. SO FAR THIS AFTERNOON...THE WARMEST TEMPERATURE
REPORTED WAS 94 DEGREES FROM EYOTA /MINNESOTA DOT/.
FOR TONIGHT...THE 18.12Z MODELS ARE IN VERY GOOD AGREEMENT THAT
A POSITIVELY TILTED SHORT WAVE TROUGH WILL MOVE NORTHEAST THROUGH
THE REGION. BUFKIT SOUNDINGS SHOW THAT THE AIR MASS BELOW 600 MB
WILL REMAIN RATHER DRY. AS A RESULT...ONLY EXPECTING A SCATTERED
TO OCCASIONALLY BROKEN DECK OF MID AND HIGH CLOUDS TO MOVE THROUGH
THE REGION. THE GREATEST PERCENTAGE OF THESE CLOUDS WILL WEST OF
THE MISSISSIPPI RIVER.
ON SATURDAY...THE MAXIMUM TEMPERATURE FORECAST IS RATHER TRICKY.
THIS IS DUE TO THE UNCERTAINTY ON HOW WARM THE TEMPERATURES WILL
BE ALOFT /NAM HAS THE SAME TEMPERATURES AS TODAY AND THE GFS IS 2C
COOLER/ AND MORE AFTERNOON CLOUDS ACROSS THE REGION. DUE TO THE
LATTER...TRENDED THE FORECAST A COUPLE OF DEGREES COOLER.
THE GFS DOES GENERATE PRECIPITATION NORTH OF THE INTERSTATE 94
CORRIDOR ON SATURDAY AFTERNOON. THIS IS DUE TO A STRONG PV ANOMALY
MOVING NORTHEAST THROUGH THE REGION. MEANWHILE THE NAM/ECMWF/GEM
HAVE A MUCH WEAKER PV ANOMALY. SINCE THE GFS IS TYPICALLY TO
ROBUST WITH THESE ANOMALIES...SO OPTED TO KEEP THE FORECAST DRY.
ANOTHER FORECAST ISSUE ON SATURDAY AFTERNOON WILL BE THE DEW
POINTS. ALL OF THE MODELS ARE SHOWING THAT THE DEW POINTS WILL
CLIMB INTO THE LOWER 60S. THIS LOOKS TO BE TOO HIGH WHEN ONE
TAKES IN ACCOUNT THE DRY AIR ALOFT. THE DEW POINT MIX DOWN TOOL
SUGGESTS THAT THE DEW POINTS WILL BE MORE IN THE LOWER AND MID
50S. THIS SEEMS MUCH MORE REALISTIC...THUS...WENT AT LEAST 5 TO 8F
LOWER THAN THE MOS VALUES.
FROM SATURDAY NIGHT INTO SUNDAY...THE MODELS CONTINUE TO STRUGGLE
WITH THE TIMING OF THE COLD FRONT THROUGH THE REGION. THE GFS
CONTINUES TO THE FASTEST...AND IT HAS THE FRONT THROUGH THE ENTIRE
AREA BY EARLY AFTERNOON. MEANWHILE THE OTHER MODELS SUGGEST THAT
THIS WILL NOT OCCUR UNTIL SUNDAY EVENING. THE MAIN DIFFERENCE IS
HOW FAST THEY MOVE THE POSITIVELY TILTED SHORTWAVE TROUGH THE
REGION. WITH THE GFS BEING FASTER WITH THIS FEATURE...IT MAKES
SENSE THAT ITS FRONT WOULD MOVE THROUGH THE REGION FASTER. DUE TO
THIS WENT WITH MORE OF BLEND FOR THE WINDS...PRECIPITATION
CHANCES...AND TEMPERATURES. WITH ALL OF THE MODELS HINTING THAT
THE BEST MOISTURE TRANSPORT WOULD BE MAINLY NORTH AND NORTHWEST OF
THE FORECAST AREA...AS A RESULT TRENDED THE HIGHEST PRECIPITATION
CHANCES FOR THESE AREAS. WHILE ML CAPES CLIMB INTO THE 1500 TO
2500 J/KG...THE 0-6 KM BULK SHEAR IS LESS THAN 30 KNOTS...SO STILL
NOT THINKING THAT THERE WILL ANY SEVERE WEATHER FROM ANY OF THESE
STORMS.
.LONG TERM...MONDAY THROUGH FRIDAY
343 PM CDT FRI MAY 18 2012
THE 18.12Z MODELS ARE STARTING TO BECOME MORE IN AGREEMENT. THEY
SHOW THAT A COLD FRONT WILL SAG SOUTHWARD INTO THE AREA ON WEDNESDAY
NIGHT AND THEN LINGER ACROSS THE AREA THROUGH FRIDAY MORNING...AND
THEN MOVE NORTH AS A WARM FRONT ON FRIDAY AFTERNOON AND NIGHT.
THE LATTER IS ASSOCIATED WITH A RIDGE BUILDING ACROSS THE EASTERN
UNITED STATES. SINCE THE LATTER HAS BEEN VERY CONSISTENT IN THE
ECMWF...THERE WAS ENOUGH CONFIDENCE TO RAISE THE TEMPERATURES A
COUPLE OF DEGREES ABOVE THE CONSALL FOR LATE NEXT WEEK.
&&
.AVIATION...THROUGH 06Z SUNDAY
1145 PM CDT FRI MAY 18 2012
SOUTHERLY FLOW WILL CONTINUE AT THE TAF SITES THROUGH THE PERIOD.
VFR CONDITIONS ARE EXPECTED THOUGH 06Z SATURDAY. WINDS HAVE
DECOUPLED AT KLSE WITH SURFACE WINDS AROUND 10 KNOTS. KARX VAD
WIND PROFILER SHOWS 2000 FOOT WINDS AT 40 KNOTS AND BOTH THE
19.02Z RAP AND 19.00Z NAM BUFKIT SOUNDINGS SHOWING 35 TO 40 KNOT
WINDS CONTINUING JUST OFF THE SURFACE. THUS DID INCLUDE LLWS AT
THE KLSE SITE THROUGH 14Z. LOW LEVEL WINDS AT KRST WILL BE MARGINAL
FOR LLWS AND WILL NOT INCLUDE. WINDS WILL PICK UP ONCE AGAIN
SATURDAY WITH SOME GUSTS TO 30 KNOTS AT KRST AND NEAR 25 KNOTS AT
KLSE. A COLD FRONT WILL THEN MOVE INTO WESTERN MINNESOTA DURING
THE AFTERNOON AND EVENING HOURS. DID MENTION VCSH AT KRST AFTER
01Z AS FRONT APPROACHES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
253 PM CDT FRI MAY 18 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS MIAMI FL
1015 AM EDT SAT MAY 19 2012
.UPDATE...UPDATED FORECAST PACKAGE TO MENTION POSSIBLE STRONG TO
SEVERE STORMS THIS AFTERNOON. 12Z SOUNDING PARAMETERS ALMOST
IDENTICAL TO FRIDAY`S VALUES. PW=1.72 INCHES, 500 MB TEMP AROUND
-10C TO -11C AND THE LIKELIHOOD OF WET MICROBURSTS AND LARGE HAIL. 850 MB
ANALYSIS ALSO SHOWS A WEAK TROUGH MOVING SLOWLY EASTWARD ACROSS
SOUTH FLORIDA. THIS COMBINED WITH PLENTY OF HEATING AND LEFT-OVER
OUTFLOW BOUNDARIES FROM YESTERDAY`S CONVECTIVE ACTIVITY WILL LEAD TO
THUNDERSTORMS DEVELOPING JUST ABOUT ANYWHERE IN S. FLORIDA. HOWEVER,
WESTERLY MID/UPPER LEVEL FLOW MAY STEER ANY STORM EASTWARD TOWARD
THE EASTERN INTERIOR AND EASTERN METRO AREAS.
.AVIATION...
THE WINDS WILL REMAIN LIGHT EARLY THIS MORNING BEFORE BECOMING
SOUTHEAST AT 5 TO 10 KNOTS AFTER 13Z TODAY. THE ONLY EXCEPTION TO
THIS IS AT KAPF WHERE THE WINDS WILL BE EASTERLY THIS MORNING BEFORE
SWINGING TO A WESTERLY DIRECTION AROUND 16Z TODAY...DUE TO THE WEST
COAST SEA BREEZE DEVELOPING AND PUSHING INLAND. CONVECTION IS
EXPECTED ACROSS THE PENINSULA TODAY...WITH VCSH ASSIGNED ALL
TERMINALS THROUGH 15Z AND VCTS ASSIGNED ALL TERMINALS AT 16Z.
MAINLY VFR CONDITIONS EXPECTED TO PREVAIL ALL TERMINALS THROUGH
15Z AND STARTING AT 16Z PERIODS OF SUB-VFR CONDITIONS AND BRIEF
PERIODS OF IFR CONDITIONS POSSIBLE WITH OCCURRENCE OF SHOWERS
AND/OR THUNDERSTORMS.
60
&&
.PREV DISCUSSION... /ISSUED 347 AM EDT SAT MAY 19 2012/
SHORT RANGE (TODAY-MONDAY)...
RECENTLY ANIMATED WATER VAPOR LOOP SHOWED A BROAD TROUGH CENTERED
OVER THE SOUTHEAST WITH A NOTABLE SHORTWAVE TROUGH EXTENDING
SOUTHWEST FROM THE FLORIDA PANHANDLE TO THE CENTRAL GULF AND PLENTY
OF MID/UPPER MOISTURE SPREADING EAST-NORTHEAST ACROSS SOUTH
FLORIDA...THE KEYS AND FLORIDA STRAITS. THE LATEST SURFACE ANALYSIS
SHOWED A WEAKNESS WITHIN THE SUBTROPICAL RIDGE ACROSS THE LOCAL AREA
WITH A TROUGH OR FRONTAL BOUNDARY EXTENDING SOUTHWEST FROM A LOW
PRESSURE CENTERED OFF THE CAROLINA COAST TO CENTRAL FL.
THE MODELS HAVE INITIALIZED WELL WITH THIS SYNOPTIC PATTERN AND
INDICATE ANOTHER POTENTIALLY ACTIVE DAY ACROSS THE FLORIDA
PENINSULA...SIMILAR TO YESTERDAY. THE AFOREMENTIONED SHORTWAVE
TROUGH WILL ROTATE EASTWARD AROUND THE BASE OF THE UPPER TROUGH
AND MOVE ACROSS THE AREA TODAY FROM WEST TO EAST...WHICH WILL LEAD
TO DECREASING UPPER HEIGHTS AND SOME COOLER MID-LEVEL AIR (-10 TO
-11 C 500 MB TEMPS) SPREADING OVER THE AREA THIS AFTERNOON. THIS
COMBINED WITH A WEAK SFC TROUGH AND LOW-LEVEL CONVERGENCE
ASSOCIATED WITH THE EAST/WEST COAST SEA BREEZES WILL BE ENOUGH TO
INITIATE ANOTHER ROUND OF AFTERNOON CONVECTION. THE ONE DIFFERENCE
TODAY COMPARED TO YESTERDAY IS THAT THE LOW-LEVEL FLOW WILL HAVE
MORE OF AN EASTERLY COMPONENT...WHICH SHOULD HELP CONCENTRATE THE
CONVECTIVE ACTIVITY OVER THE INTERIOR SECTIONS INITIALLY. THE
LATEST HRRR MODEL REFLECTIVITIES LINE UP WELL WITH THIS AND
GENERALLY INDICATE CONVECTION BEGINNING BY 18Z OVER THESE INTERIOR
LOCATIONS. WITH THE DRIER/COOLER MID-LEVEL AIR EXPECTED...THE MAIN
THREATS WITH THE STRONGER STORMS THAT DEVELOP WILL BE DAMAGING
STRAIGHT LINE WINDS AND HAIL.
TONIGHT THROUGH MONDAY...SIMILAR CONDITIONS WILL BE EXPECTED EACH
DAY WITH SCATTERED AFTERNOON SHOWERS/TSTMS DEVELOPING OVER THE
INTERIOR SECTIONS ASSOCIATED WITH THE PERSISTENT UPPER TROUGH AND
AFTERNOON SEA BREEZES.
LONG RANGE (MONDAY NIGHT-FRIDAY)...
THE GFS/GFS ENSEMBLE MEAN/ECMWF GENERALLY ALL MAINTAIN THE
MID/UPPER TROUGH OVER THE SOUTHEAST REGION WITH DRY MID/UPPER
WESTERLY FLOW CONTINUING ACROSS THE FL PENINSULA. AT THE
SURFACE...ALTHOUGH THERE REMAINS SOME DIFFERENCES NOTED BETWEEN THE
MODEL SOLUTIONS...THE GFS/ECMWF GENERALLY INDICATE A WEAK TROUGH
EXTENDING NORTHEAST FROM A BROAD LOW CENTERED OVER THE WESTERN
CARIBBEAN ACROSS THE FLORIDA STRAITS...WHICH MAY HELP CONCENTRATE
ANY DEEP MOIST CONVECTION JUST SOUTH OF OUR LOCAL AREA ACROSS THE
KEYS AND STRAITS. OTHERWISE...MORE OF A SEASONAL PATTERN WITH 20-30
PERCENT RAINFALL CHANCES EACH DAY ASSOCIATED WITH THE AFTERNOON SEA
BREEZES WILL REMAIN IN THE FORECAST. TEMPERATURES WILL REMAIN AROUND
NORMAL THROUGH THIS TIME WITH HIGHS IN THE UPPER 80S AND LOWS IN THE
LOWER 70S.
MARINE...
A WEAK PRESSURE GRADIENT WILL RESULT IN LIGHT EASTERLY WINDS
AND LOW SEAS CONTINUING THROUGH THE WEEKEND AND INTO THE UPCOMING
WEEK. SCATTERED SHOWERS AND THUNDERSTORMS COULD LEAD TO BRIEF
PERIODS WITH LOCALLY HIGHER WINDS AND SEAS.
AVIATION...
THE WINDS WILL REMAIN LIGHT EARLY THIS MORNING BEFORE BECOMING
SOUTHEAST AT 5 TO 10 KNOTS AFTER 13Z TODAY. THE ONLY EXCEPTION TO
THIS IS AT KAPF WHERE THE WINDS WILL BE EASTERLY THIS MORNING
BEFORE SWINGING TO A WESTERLY DIRECTION AROUND 17Z TODAY...DUE TO
THE WEST COAST SEA BREEZE DEVELOPING AND PUSHING INLAND.
THE WEATHER WILL ALSO REMAIN DRY THROUGH 13Z TODAY...BEFORE VCSH
FOR ALL TAF SITES BETWEEN 13Z AND 17Z. THUNDERSTORMS WILL THEN
DEVELOP THIS AFTERNOON ALONG THE SEA BREEZE AND PUSH SLOWLY INLAND
OVER THE COAST AREAS...WHILE THE WEST COAST SEA BREEZE PUSHES MORE
INLAND. SO WILL INTRODUCE VCTS FOR THE EAST COAST TAF SITES
BETWEEN 17Z AND 23Z TODAY...WHILE THE KAPF TAF SITE REMAINS IN THE
VCSH FOR THE AFTERNOON HOURS. THE ACTIVITY WILL THEN DISSIPATE
BETWEEN 00Z AND 02Z TONIGHT OVER ALL OF THE TAF SITES...AS THE
HEATING OF THE DAY IS LOST. SO AFTER 02Z TONIGHT THE WEATHER WILL
BE DRY AGAIN.
THE CEILING AND VIS WILL REMAIN IN THE VFR CONDITIONS THROUGH
TODAY...DUE TO THE UNKNOWN TIMING OF THE SHOWERS AND THUNDERSTORMS
FOR TODAY.
FIRE WEATHER...
SOME STRONG TO SEVERE STORMS ARE POSSIBLE THIS AFTERNOON OVER
SOUTH FLORIDA ESPECIALLY WHERE THE EAST AND WEST COAST SEA BREEZES
COLLIDE OVER THE INTERIOR AREAS. THE PRIMARY IMPACTS FROM THE
STRONGEST STORMS WILL BE FREQUENT LIGHTNING STRIKES...GUSTY
WINDS...HAIL UP TO QUARTER SIZE...AND HEAVY RAINFALL. THE BEST
TIME TO SEE THE STORMS WILL IN THE AFTERNOON AND EARLY EVENING HOURS.
THE RELATIVE HUMIDITIES TODAY WILL REMAIN ABOVE THE 35 PERCENT
CRITICAL VALUE..AS THE DISPERSION INDEX WILL RANGE FROM THE 20S
INTERIOR AREAS TO 40 ALONG THE METRO AREAS. THE DISPERSION INDEX
FOR TONIGHT WILL BE LESS THAN 5. THIS MEANS THAT THE MIXING FOR
TODAY IS IN THE FAIR TO GOOD RANGE...WHILE TONIGHT IT IS IN THE
VERY POOR RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 85 71 85 73 / 50 40 30 20
FORT LAUDERDALE 85 72 86 74 / 50 40 30 20
MIAMI 86 73 86 73 / 50 40 30 20
NAPLES 86 70 86 71 / 40 20 40 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...47/RGH
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS MIAMI FL
730 AM EDT SAT MAY 19 2012
.AVIATION...
THE WINDS WILL REMAIN LIGHT EARLY THIS MORNING BEFORE BECOMING
SOUTHEAST AT 5 TO 10 KNOTS AFTER 13Z TODAY. THE ONLY EXCEPTION TO
THIS IS AT KAPF WHERE THE WINDS WILL BE EASTERLY THIS MORNING BEFORE
SWINGING TO A WESTERLY DIRECTION AROUND 16Z TODAY...DUE TO THE WEST
COAST SEA BREEZE DEVELOPING AND PUSHING INLAND. CONVECTION IS
EXPECTED ACROSS THE PENINSULA TODAY...WITH VCSH ASSIGNED ALL
TERMINALS THROUGH 15Z AND VCTS ASSIGNED ALL TERMINALS AT 16Z.
MAINLY VFR CONDITIONS EXPECTED TO PREVAIL ALL TERMINALS THROUGH
15Z AND STARTING AT 16Z PERIODS OF SUB-VFR CONDITIONS AND BRIEF
PERIODS OF IFR CONDITIONS POSSIBLE WITH OCCURRENCE OF SHOWERS
AND/OR THUNDERSTORMS.
60
&&
.PREV DISCUSSION... /ISSUED 347 AM EDT SAT MAY 19 2012/
SHORT RANGE (TODAY-MONDAY)...
RECENTLY ANIMATED WATER VAPOR LOOP SHOWED A BROAD TROUGH CENTERED
OVER THE SOUTHEAST WITH A NOTABLE SHORTWAVE TROUGH EXTENDING
SOUTHWEST FROM THE FLORIDA PANHANDLE TO THE CENTRAL GULF AND PLENTY
OF MID/UPPER MOISTURE SPREADING EAST-NORTHEAST ACROSS SOUTH
FLORIDA...THE KEYS AND FLORIDA STRAITS. THE LATEST SURFACE ANALYSIS
SHOWED A WEAKNESS WITHIN THE SUBTROPICAL RIDGE ACROSS THE LOCAL AREA
WITH A TROUGH OR FRONTAL BOUNDARY EXTENDING SOUTHWEST FROM A LOW
PRESSURE CENTERED OFF THE CAROLINA COAST TO CENTRAL FL.
THE MODELS HAVE INITIALIZED WELL WITH THIS SYNOPTIC PATTERN AND
INDICATE ANOTHER POTENTIALLY ACTIVE DAY ACROSS THE FLORIDA
PENINSULA...SIMILAR TO YESTERDAY. THE AFOREMENTIONED SHORTWAVE
TROUGH WILL ROTATE EASTWARD AROUND THE BASE OF THE UPPER TROUGH
AND MOVE ACROSS THE AREA TODAY FROM WEST TO EAST...WHICH WILL LEAD
TO DECREASING UPPER HEIGHTS AND SOME COOLER MID-LEVEL AIR (-10 TO
-11 C 500 MB TEMPS) SPREADING OVER THE AREA THIS AFTERNOON. THIS
COMBINED WITH A WEAK SFC TROUGH AND LOW-LEVEL CONVERGENCE
ASSOCIATED WITH THE EAST/WEST COAST SEA BREEZES WILL BE ENOUGH TO
INITIATE ANOTHER ROUND OF AFTERNOON CONVECTION. THE ONE DIFFERENCE
TODAY COMPARED TO YESTERDAY IS THAT THE LOW-LEVEL FLOW WILL HAVE
MORE OF AN EASTERLY COMPONENT...WHICH SHOULD HELP CONCENTRATE THE
CONVECTIVE ACTIVITY OVER THE INTERIOR SECTIONS INITIALLY. THE
LATEST HRRR MODEL REFLECTIVITIES LINE UP WELL WITH THIS AND
GENERALLY INDICATE CONVECTION BEGINNING BY 18Z OVER THESE INTERIOR
LOCATIONS. WITH THE DRIER/COOLER MID-LEVEL AIR EXPECTED...THE MAIN
THREATS WITH THE STRONGER STORMS THAT DEVELOP WILL BE DAMAGING
STRAIGHT LINE WINDS AND HAIL.
TONIGHT THROUGH MONDAY...SIMILAR CONDITIONS WILL BE EXPECTED EACH
DAY WITH SCATTERED AFTERNOON SHOWERS/TSTMS DEVELOPING OVER THE
INTERIOR SECTIONS ASSOCIATED WITH THE PERSISTENT UPPER TROUGH AND
AFTERNOON SEA BREEZES.
LONG RANGE (MONDAY NIGHT-FRIDAY)...
THE GFS/GFS ENSEMBLE MEAN/ECMWF GENERALLY ALL MAINTAIN THE
MID/UPPER TROUGH OVER THE SOUTHEAST REGION WITH DRY MID/UPPER
WESTERLY FLOW CONTINUING ACROSS THE FL PENINSULA. AT THE
SURFACE...ALTHOUGH THERE REMAINS SOME DIFFERENCES NOTED BETWEEN THE
MODEL SOLUTIONS...THE GFS/ECMWF GENERALLY INDICATE A WEAK TROUGH
EXTENDING NORTHEAST FROM A BROAD LOW CENTERED OVER THE WESTERN
CARIBBEAN ACROSS THE FLORIDA STRAITS...WHICH MAY HELP CONCENTRATE
ANY DEEP MOIST CONVECTION JUST SOUTH OF OUR LOCAL AREA ACROSS THE
KEYS AND STRAITS. OTHERWISE...MORE OF A SEASONAL PATTERN WITH 20-30
PERCENT RAINFALL CHANCES EACH DAY ASSOCIATED WITH THE AFTERNOON SEA
BREEZES WILL REMAIN IN THE FORECAST. TEMPERATURES WILL REMAIN AROUND
NORMAL THROUGH THIS TIME WITH HIGHS IN THE UPPER 80S AND LOWS IN THE
LOWER 70S.
MARINE...
A WEAK PRESSURE GRADIENT WILL RESULT IN LIGHT EASTERLY WINDS
AND LOW SEAS CONTINUING THROUGH THE WEEKEND AND INTO THE UPCOMING
WEEK. SCATTERED SHOWERS AND THUNDERSTORMS COULD LEAD TO BRIEF
PERIODS WITH LOCALLY HIGHER WINDS AND SEAS.
AVIATION...
THE WINDS WILL REMAIN LIGHT EARLY THIS MORNING BEFORE BECOMING
SOUTHEAST AT 5 TO 10 KNOTS AFTER 13Z TODAY. THE ONLY EXCEPTION TO
THIS IS AT KAPF WHERE THE WINDS WILL BE EASTERLY THIS MORNING
BEFORE SWINGING TO A WESTERLY DIRECTION AROUND 17Z TODAY...DUE TO
THE WEST COAST SEA BREEZE DEVELOPING AND PUSHING INLAND.
THE WEATHER WILL ALSO REMAIN DRY THROUGH 13Z TODAY...BEFORE VCSH
FOR ALL TAF SITES BETWEEN 13Z AND 17Z. THUNDERSTORMS WILL THEN
DEVELOP THIS AFTERNOON ALONG THE SEA BREEZE AND PUSH SLOWLY INLAND
OVER THE COAST AREAS...WHILE THE WEST COAST SEA BREEZE PUSHES MORE
INLAND. SO WILL INTRODUCE VCTS FOR THE EAST COAST TAF SITES
BETWEEN 17Z AND 23Z TODAY...WHILE THE KAPF TAF SITE REMAINS IN THE
VCSH FOR THE AFTERNOON HOURS. THE ACTIVITY WILL THEN DISSIPATE
BETWEEN 00Z AND 02Z TONIGHT OVER ALL OF THE TAF SITES...AS THE
HEATING OF THE DAY IS LOST. SO AFTER 02Z TONIGHT THE WEATHER WILL
BE DRY AGAIN.
THE CEILING AND VIS WILL REMAIN IN THE VFR CONDITIONS THROUGH
TODAY...DUE TO THE UNKNOWN TIMING OF THE SHOWERS AND THUNDERSTORMS
FOR TODAY.
FIRE WEATHER...
SOME STRONG TO SEVERE STORMS ARE POSSIBLE THIS AFTERNOON OVER
SOUTH FLORIDA ESPECIALLY WHERE THE EAST AND WEST COAST SEA BREEZES
COLLIDE OVER THE INTERIOR AREAS. THE PRIMARY IMPACTS FROM THE
STRONGEST STORMS WILL BE FREQUENT LIGHTNING STRIKES...GUSTY
WINDS...HAIL UP TO QUARTER SIZE...AND HEAVY RAINFALL. THE BEST
TIME TO SEE THE STORMS WILL IN THE AFTERNOON AND EARLY EVENING HOURS.
THE RELATIVE HUMIDITIES TODAY WILL REMAIN ABOVE THE 35 PERCENT
CRITICAL VALUE..AS THE DISPERSION INDEX WILL RANGE FROM THE 20S
INTERIOR AREAS TO 40 ALONG THE METRO AREAS. THE DISPERSION INDEX
FOR TONIGHT WILL BE LESS THAN 5. THIS MEANS THAT THE MIXING FOR
TODAY IS IN THE FAIR TO GOOD RANGE...WHILE TONIGHT IT IS IN THE
VERY POOR RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 85 71 85 73 / 50 40 30 20
FORT LAUDERDALE 85 72 86 74 / 50 40 30 20
MIAMI 86 73 86 73 / 50 40 30 20
NAPLES 86 70 86 71 / 40 20 40 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...47/RGH
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
636 AM CDT SAT MAY 19 2012
.UPDATE...
SEE THE CLIMATE SECTION REGARDING RECORD HIGHS FOR MAY 19TH.
A VERY MINOR TWEAK WAS DONE WITH THE HRLY TEMPERATURES TO BETTER
REFLECT CURRENT TRENDS. BASED ON FCST MAX TEMPERATURES TODAY SOME
SITES MAY BE NEAR RECORD TERRITORY. EVERYTHING WILL DEPEND UPON
THE AMOUNT OF CI/CS BLOW OFF FROM CONVECTION ALONG THE MISSOURI
RIVER. RAP TRENDS WITH THE LIFT TOOL INDICATES THAT THIS
CONVECTION WILL DISSIPATE DURING THE MORNING AS THE LLJ WEAKENS.
THE OUTFLOW BOUNDARY WOULD PROVIDE A FOCUS FOR DIURNAL CONVECTION
DURING THE AFTERNOON.
THE LIFT TOOL AND RAP TRENDS STILL INDICATE CONVECTION SHOULD FIRE
CLOSE TO THE MISSOURI RIVER THIS AFTERNOON BUT THERE MAY BE SOME
ISOLATED TO SCATTERED CONVECTION DEVELOPING ON THE REMNANT OUTFLOW
BOUNDARY IN CENTRAL IOWA LATE THIS AFTERNOON. THE LIFT TOOL STILL
SUGGESTS THE LATE AFTERNOON AND EVENING HOURS SHOULD BE DRY IN THE
CWFA. ..08..
&&
.AVIATION...
VFR WX WILL BE SEEN THROUGH 09Z/20. INVERSION SHOULD BREAK 15Z-
16Z/19 ALLOWING DEEPER MIXING TO OCCUR AND INCREASE WINDS. WINDS
SHOULD DROP OFF AROUND 00Z/20 AS THE INVERSION BECOMES RE-
ESTABLISHED. KCID HAS THE BEST CHANCE AT SEEING VCTS AFT 09Z/20
BUT CONVECTION MAY HOLD OFF UNTIL 12Z/20 OR LATER. IF CONVECTION
DOES OCCUR AT KCID THERE WOULD BE A POTENTIAL FOR MVFR CONDITIONS.
KDBQ/KMLI/KBRL ARE EXPECTED TO REMAIN VFR THROUGH 12Z/20. ..08..
&&
.CLIMATE...
RECORD HIGHS FOR MAY 19...
MOLINE.........93 IN 1962
CEDAR RAPIDS...93 IN 1975
DUBUQUE........93 IN 1934
BURLINGTON.....93 IN 1998
&&
.PREV DISCUSSION... /ISSUED 305 AM CDT SAT MAY 19 2012/
SYNOPSIS...
06Z SFC ANALYSIS HAS THE FRONT WITH LOW PRESSURE CENTERS ALONG IT
RUNNING FROM NORTHWEST MINNESOTA INTO NORTHERN COLORADO. A MESO HIGH
ASSOCIATED WITH A SMALL MCS WAS ACROSS NEBRASKA WHILE A DRY LINE RAN
FROM FROM NEAR KMCK TO KCVS. DEW POINTS WERE IN THE 40S ACROSS THE
GREAT LAKES WITH 50S OVER MUCH OF THE MIDWEST.
SHORT TERM...TODAY AND TONIGHT
VERY WARM AND BREEZY CONDITIONS WILL BE SEEN ACROSS THE AREA TODAY.
IF THE SAME NEAR 30 DEGREE DIURNAL SWING TAKES PLACE TODAY THEN MAX
TEMPS WOULD BE IN THE LOW TO MID 90S. THE OVERALL WAA AND DEPTH OF
DEEP MIXING JUST DOES NOT SUPPORT TEMPERATURES THAT WARM. HOWEVER...
PERSISTENCE PLUS SEVERAL DEGREES WOULD SUPPORT UPPER 80S TO LOWER
90S FOR MAX TEMPS. DEW POINTS WILL BE ROUGHLY 10 DEGREES WARMER THAN
YESTERDAY BUT HUMIDITY LEVELS WILL STILL BE LOW.
TONIGHT...THE EVENING HOURS WILL BE DRY. MCS AND LIFT TOOLS INDICATE
CONVECTION WILL FIRE LATE THIS AFTERNOON/EVENING IN WESTERN IOWA
PROBABLY NOT FAR FROM THE MISSOURI RIVER. THE QUESTION IS WHETHER
SAID CONVECTION WILL MAKE IT INTO THE CWFA PRIOR TO SUNRISE.
INTERESTINGLY...ALL MODELS WEAKEN THE CONVERGENCE AFTER MIDNIGHT
ACROSS THE AREA. MCS...LIFT...AND HEAVY RAIN TOOLS OFFER MIXED
SIGNALS ON PRECIPITATION POTENTIAL. WHEN THE LIFT TOOL IS APPLIED TO
ALL THE MODELS...A WEAK BUT CONSISTENT SIGNAL EMERGES SUGGESTING THE
POSSIBILITY OF CONVECTION ENTERING THE FAR WESTERN CWFA JUST PRIOR
TO DAWN. SO...WILL CONFINE ANY PRECIP TO VERY LATE TONIGHT OVER THE
WESTERN QUARTER OR SO OF THE CWFA. HOWEVER...THE CONSISTENT
WEAKENING OF THE OVERALL CONVERGENCE BY THE MODELS DOES QUESTION THE
POTENTIAL FOR ANY PRECIPITATION ENTERING THE CWFA. ..08..
LONG TERM...SUNDAY THROUGH NEXT FRIDAY
SUNDAY THROUGH SUNDAY EVENING CONTINUES TO REPRESENT A FRONTAL
PASSAGE...WITH MODEST AT BEST MOISTURE...AND WEAK FORCING. THE
TIMING APPEARS TO HAVE SLOWED JUST ENOUGH TO HAVE THE FRONT WITHIN
EASTERN IOWA AT 18 TO 00Z...AND THUS A DIURNAL INCREASE IN
CONVECTION SHOULD AFFECT OUR CWA UNLESS THE TIMING SPEEDS UP AGAIN.
THE 18Z TO 00Z FROPA IS CONSISTENT IN MODEL GUIDANCE OTHER THAN THE
NAM...WHICH REMAINS 3 HOURS FASTER. QPF SHOULD BE GENERALLY
LIGHT...WITH BENEFICIAL AMOUNTS SPOTTY IN EXCESS OF A QUARTER INCH.
ANY STRONG STORMS WILL DEPEND GREATLY ON CAPE...AND AT THIS
POINT...WE ARE EXPECTING HIGHS IN THE LOWER TO MID 80S...WITH
DEWPOINTS AROUND 60. THIS WILL BE SUFFICIENT FOR THUNDER...BUT
DEPENDING ON WARM MID LEVEL TEMPS...WE MAY NOT SEE A LARGE CAPE
POOL.
BY LATER SUNDAY NIGHT...CAA AND DRY AIR SHOULD SWEEP IN...ENDING ANY
RAINFALL THREAT. MONDAY THROUGH TUESDAY...COOLER CANADIAN AIR SHOULD
BE OVER THE REGION...WITH HIGHS IN THE LOWER TO MID 70S...AND LOWS
IN THE LOWER TO MID 50S. THIS TWO DAY PERIOD REPRESENTS THE COOLEST
PORTION OF THE EXTENDED.
WEDNESDAY NIGHT THROUGH FRIDAY...THERE REMAIN LARGE DIFFERENCES IN
MODEL DATA. THE GFS CONTINUES TO SHIFT THE TROF/RIDGE EAST FAR
ENOUGH DURING THIS PERIOD TO WARRANT SHOWERS AND THUNDERSTORMS IN
OUR CWA BEGINNING THURSDAY. SHOULD THE GFS BE CORRECT...WITH SOME
SUPPORT FROM THE UKMET AS WELL...THIS MAY BE THE BEGINNING OF A 2 TO
4 DAY PERIOD OF ACTIVE STORMS. HOWEVER...CAPPING IS MOST CERTAINLY
GOING TO BE AN ISSUE...WITH THE ECMWF...CONSISTENTLY...SHOWING THE
ENTIRE PERIOD BEING HOT AND COMPLETELY DRY. WHILE BOTH
POSSIBILITIES REMAIN POSSIBLE...IT IS HARD TO IGNORE SUCH A STRONG
ECMWF SIGNAL TOWARDS SUNSHINE AND HOT AIR.
ERVIN
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
753 AM EDT SAT MAY 19 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 508 AM EDT SAT MAY 19 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG OVER THE
GREAT LAKES DOWNSTREAM OF TROF IN THE ROCKIES. CWA IS IN THE WARM
SECTOR E OF SFC-H85 TROF/COLD FNT AND S OF WARM FNT OVER NRN LK SUP/
ADJOINING ONTARIO. WITH DRYNESS SHOWN ON LOCAL 00Z RAOBS /H925 DEWPT
DEPRESSIONS ARE 15 TO 25C ON THE MPX/GRB RAOBS AND THE H85 DEWPT
DEPRESSION AT GRB WAS 49C/...SKIES ARE MOCLR OVER UPR MI. DESPITE
THE CLEAR SKIES/DRY AIR AND LOCAL DECOUPLING... TEMPS ARE WELL ABV
NORMAL WITH STEADY SW FLOW AT H925 LIMITING THE OVERALL DIURNAL TEMP
DROP. SOME SHRA/TS DID IMPACT MUCH OF MN THIS PAST EVNG DESPITE
FAIRLY DRY AIR.AS SHRTWV LIFTED NNEWD WELL E OF THE MAIN TROF TO THE
W...BUT THESE ARE TENDING TO WEAKEN AND STAY W OF EVEN LK SUP. MORE
WIDESPREAD SHRA/TS ARE LOCATED IN THE PLAINS CLOSER TO H85 COLD FNT.
MAIN FCST CONCERNS TDAY ARE FOCUSED ON FIRE WX. FOCUS FOR TNGT THRU
SUN SHIFTS TO SHRA/TS CHCS ASSOCIATED WITH SLOWLY APRCHG UPR TROF/
COLD FNT.
TDAY...CWA WL REMAIN UNDER WARM SW FLOW AS COLD FNT TO THE W SLIDES
EWD THRU MN. ALTHOUGH H85 TEMPS ARE FCST TO AVG ABOUT A DEGREE LOWER
THAN YDAY...VERY DEEP MIXING SHOWN ON THE 00Z MPX RAOB SHOULD
SUPPORT MAX TEMPS NEARLY SIMILAR TO WHAT OCCURRED ON FRI PER
UPSTREAM OBSVD SFC HI TEMPS...WITH SOME PLACES OVER THE W HALF
SEEING THE MERCURY REACH 90. GOING FCST SHOWING THESE HIER TEMPS IN
THE DOWNSLOPE AREAS FM ONTONAGON TO BARAGA LOOK ON TRACK. AREAS OVER
THE E HALF SHOULD SEE SOME MODERATION OFF LK MI. SOME LK MODERATION
MAY SLIP A BIT FARTHER W INTO THE CNTRL IF FCST BACKING WINDS TO
MORE DUE S DRAGS THE LK MI MODERATION INTO THAT AREA. SEE FIRE WX
SECTION BLO FOR A DISCUSSION OF FIRE WX CONCERNS.
TNGT...WITH BLDG UPR RDG FCST OVER THE ERN GRT LKS...OPTED TO FOLLOW
THE SOMEWHAT SLOWER 12Z ECMWF/00Z CNDN MODELS FOR THE TIMING OF THE
COLD FNT...ESPECIALLY SINCE A SHRTWV LIFTING NEWD OUT OF THE ROCKIES
WL INDUCE A LOW PRES TO DVLP ON THIS BNDRY OVER THE PLAINS TDAY.
THIS LO IS FCST TO MOVE INTO MN BY 12Z SUN. THE 00Z NAM HAS TRENDED
IN THIS DIRECTION AS WELL. IN FACT...THE 12Z ECMWF/0Z CNDN MODELS
INDICATE THE BULK OF ANY PCPN WL BE ON THE COLD SIDE OF THE FNT
AND STAY W OF IWD THRU 12Z. THIS FCST IS REASONABLE CONSIDERING THE
DRYNESS OF THE WARM SECTOR AIRMASS AND FCST DEEP LYR QVECTOR CNVGC
BEING FOCUSED UNDER THE SHARPER DPVA ASSOCIATED WITH THE SHRTWV ON
THE COLD SIDE OF THE FNT IN MN EVEN AS LATE AS 12Z SUN. STEADY SW
FLOW IN THE WARM SECTOR SHOULD ONCE AGAIN LIMIT THE DIURNAL FALL OF
TEMP...SO MINS WL BE WELL ABV NORMAL AGAIN.
SUN...SINCE THE FAVORED 12Z ECMWF/00Z CNDN MODELS SHOW BULK OF DEEP
LYR QVECTOR CNVGC SHIFTING NEWD THRU WRN LK SUP TOWARD ONTARIO...
SUSPECT THE HIER POPS WL BE OVER THE NW CWA...WITH PCPN TENDING TO
DIMINISH AS THE FNT SHIFTS TO THE E INTO THE CENTRAL CWA BY LATE
AFTN. HOWEVER...DAYTIME HEATING MAY OFFSET THE LOSS OF BEST
DYNAMICS...ESPECIALLY SINCE THE CNDN MODEL SHOWS HIER H85 DWPTS UP
TO 12C SURGING NEWD RIGHT ALONG THE FNT. HOWEVER...THIS SOMEWHAT
HIER MSTR IS STILL RELATIVELY LO COMPARED TO H85 TEMPS FCST ARND
16C. SO THE LLVLS WL STILL BE RATHER DRY PER THE MODEL FCST
SDNGS...LIMITING DESTABILIZATION. OPTED TO GO WITH LIKELY POPS OVER
THE NW CWA...DIMINISHING TO CHC FARTHER TO THE E. RAISED FCST HI
TEMPS WELL INTO THE 80S OVER THE E AND CNTRL AWAY FM LK MI
MODERATION TO ACCOUNT FOR SLOWER ARRIVAL OF COLD FNT.
SUN NGT...EXPECT COLD FNT TO PUSH THRU THE REST OF THE CWA
ACCOMPANIED BY CHC POPS AS MAIN SHRTWV/SHARPEST DEEP LYR QVECTOR
CNVGC EXITS TO THE NE AND ANY HELP FM DIURNAL HEATING WANES. SINCE
GUIDANCE HINTS AT THE ARPCH OF A SECOND SHRTWV FM MN...MAINTAINED
THE CHC POPS HANGING WELL BACK BEHIND THE COLD FNT AS HINTED AT BY
00Z NAM/12Z ECWMF AND SHOWN IN PREVIOUS FCST DESPITE MID LVL DRYING
IN THE WAKE OF THE INITIAL DISTURBANCE. IF THIS TRAILING SHRTWV IS
WEAKER...THE DRYING BEHIND THE FIRST STRONGER SHRTWV MAY END THE
POPS FASTER THAN FCST AS FCST BY THE 00Z CNDN. THE ARRIVAL OF H85
TEMPS AOB 5C OVER THE W BY 12Z MON WL BRING A RETURN OF MORE
SEASONABLE TEMPS.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 508 AM EDT SAT MAY 19 2012
A SLOWLY TRANSITIONING WX PATTERN...WITH MUCH OF THE PERIOD
CONTINUING TO BE DOMINATED BY SOUTHERLY WINDS.
INITIALLY WE WILL HAVE THE EXITING COLD FRONT TO OUR EAST...AND HIGH
PRESSURE PUSHING IN FROM THE CENTRAL AND N PLAINS. AS A
RESULT...EXPECT TEMPS TO BE 10 TO 15 DEGREES COOLER THAN SUNDAY.
850MB TEMPS WILL BE 4-5C. WITH THE COOL TEMPS WILL COME DRY
AIR...WITH LOWER DEWPOINTS MONDAY AFTERNOON INTO THE MID 30S OVER
THE W HALF. WOULD NOT BE COMPLETELY SHOCKED TO SEE VALUES CLOSER TO
30F...WHICH WOULD GIVE RH VALUES NEAR 25 PERCENT.
THE SFC HIGH WILL BE DIRECTLY OVERHEAD TUESDAY MORNING...BEFORE
SLIDING E. EXPECT THE RETURN OF S WINDS...AND A LITTLE BETTER
MOISTURE. WE WILL SEE STRONGER SOUTHERLY WINDS RETURN BRIEFLY
WEDNESDAY AFTERNOON. ADJUSTED MAX TEMPS UP OVER THE TRADITIONAL
DOWNSLOPE AREAS NEAR LAKE SUPERIOR...WITH 850MB TEMPS RISING TO 11
TO 15C WITH THE COOLEST VALUES EAST.
WENT ABOVE CONSENSUS FOR HIGH TEMPS THURSDAY...ONCE AGAIN WITH A
MORE SIGNIFICANT INCREASE TO DOWNSLOPE AREAS. 850MB WINDS PEG OUT
BETWEEN 45 AND 60KTS...AND TEMPS JUMP UP TO 15-18C. THE 19/00Z GFS
IS ONE OF THE COOLEST SOLUTIONS.
WILL BE INTERESTING HOW THE END OF THE WORK WEEK PANS OUT...AND IF
THE FRONTAL BOUNDARY SETS UP AND STALLS OVER THE W CWA LIKE THE
19/00Z ECMWF...OR BLOWS THROUGH OUR AREA THURSDAY NIGHT BEFORE
STALLING OVER LOWER MI FRIDAY INTO SATURDAY. WILL NOT GET TOO FANCY
WITH THE FORECAST THAT FAR OUT...AND WILL KEEP THE SLIGHT CHANCE/LOW
CHANCE POPS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 752 AM EDT SAT MAY 19 2012
VFR CONDITIONS WILL REMAIN...WITH HIGH CLOUDS SLOWLY INVADING FROM THE
WEST AND LOWERING LOWER THE NEXT 24HRS. WINDS WILL CONTINUE TO BE THE
MAIN STORY...WITH 30-40KT WINDS JUST ABOVE THE SFC AND MIXED LAYER
THIS AFTERNOON...PARTICULARLY AT SAW AND IWD GIVEN THE FAVORABLE
DOWNSLOPE FLOW. WHILE THERE IS A SMALL POSSIBILITY OF A SHOWER OR TS
AT IWD JUST PRIOR TO DAYBREAK...BUT TOO SMALL OF A CHANCE TO INCLUDE
IN THE TAFS QUITE YET. &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EDT SAT MAY 19 2012
WINDS SHOULD REMAIN BELOW 30KTS THROUGH THE PERIOD. LOW PRESSURE
STRETCHING FROM SOUTHWESTERN QUEBEC TO NEBRASKA WILL SHIFT
NORTHEASTWARD...FILLING SLIGHTLY AS IT CROSSES LAKE SUPERIOR SUNDAY
INTO SUNDAY EVENING. BEHIND THIS FEATURE...HIGH PRESSURE WILL BUILD
ACROSS THE UPPER GREAT LAKES MONDAY AND MONDAY NIGHT. EXPECT THE
HIGH TO SLOWLY EXIT NORTHEASTWARD THROUGH MID WEEK...IN RESPONSE TO
A STRONGER LOW NEARING FROM SOUTH CENTRAL CANADA THROUGH THE CENTRAL
PLAINS. EXPECT THE LOW TO OUR WEST TO MOVE OVER ONTARIO ON
THURSDAY...BEFORE EDGING ACROSS LAKE SUPERIOR THURSDAY NIGHT.
&&
.FIRE WEATHER...
ISSUED AT 508 AM EDT SAT MAY 19 2012
AFTER AN OVERNGT OF RELATIVELY POOR RH RECOVERY...EXPECT ANOTHER DAY
OF AT LEAST NEAR CRITICAL FIRE WX PARAMETERS. MAX TEMPS THIS AFTN
WILL BE SIMILAR TO WHAT WAS OBSVD YDAY...BUT DEEPER MIXING SHOWN
ESPECIALLY ON THE 00Z MPX RAOB MIGHT TAP INTO LOWER DEWPTS. IN
FACT...SFC DEWPTS WERE AS LO AS 35 TO 45 UPSTREAM YDAY AFTN IN WRN
WI/SRN MN. BLENDED MIXED DEWPT TOOL VALUES WITH THE PREVIOUS FCST
DEWPTS TO COME UP WITH READINGS DIPPING AS LO AS 43 OR SO. WITH
WINDS ALOFT TDAY ALSO NEARLY SIMILAR TO YDAY AND DEEP MIXING RELATED
TO DAYTIME HEATING... SUSTAINED WINDS AS HI AS 10 TO 20 MPH WITH
GUSTS TO 30 MPH AT THE MORE EXPOSED LOCATIONS ARE LIKELY. OPTED TO
ISSUE RFW FOR AN ARK FROM IWD/ONTONAGON TO BARAGA/MQT
COUNTIES...AREAS THAT SAW THE POOREST RH RECOVERY EARLY THIS MRNG
AND WHERE STRONGER WINDS/HIER DAYTIME HI TEMPS ARE MOST LIKELY. WL
ISSUE RFD FOR THE OTHER COUNTIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
RED FLAG WARNING FROM 1 PM EDT /NOON CDT/ THIS AFTERNOON TO 8 PM
EDT /7 PM CDT/ THIS EVENING FOR MIZ002-004-005-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KF
MARINE...KF
FIRE WEATHER...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
708 AM CDT SAT MAY 19 2012
.UPDATE...
UPDATED FOR AVIATION DISCUSSION BELOW.
&&
.DISCUSSION...
/ISSUED 429 AM CDT SAT MAY 19 2012/
WATER VAPOR IMAGERY AND RUC H5 ANALYSIS SHOWS A RATHER EXPANSIVE
RIDGE IN PLACE THIS MORNING EAST OF THE MS RIVER...WITH A RATHER
COMPLEX TROUGH MOVING INTO THE HIGH PLAINS...WITH SEVERAL
SHORTWAVES EMBEDDED WITHIN IT. THE TWO PRIMARY ONES ARE CURRENTLY
OVER ERN SODAK AND MOVING FROM CO UP INTO SRN NEB. AT THE
SFC...A COUPLE OF AREAS OF LOW PRESSURE COULD BE FOUND OVER FAR NW
ONTARIO...WITH ANOTHER NEAR THE CO/NEB/KS BORDER. A COLD FRONT IS
ANALYZED BETWEEN THESE LOWS ACROSS THE ERN DAKOTAS.
FOR THE H5 PATTERN...THE RIDGING NOW MOVING ON TO THE HIGH PLAINS
WILL SLOWLY BEAT DOWN THE ERN RIDGE...WITH THE TROUGH CURRENTLY
COMING OUT OF CO WORKING ACROSS THE MPX CWA SUN INTO SUN EVENING.
FOR MON/TUE...RIDGING WILL BE BUILDING IN ACROSS CENTRAL NOAM AS A
SIGNIFICANT TROUGH DIGS INTO THE PAC NW. AS WE HEAD THROUGH THE
SECOND HALF OF NEXT WEEK...THIS PATTERN LOOKS BECOME QUITE
AMPLIFIED...AS VERY HIGH HEIGHTS SET UP INTO THE GREAT
LAKES...WITH A QUASI-STATIONARY DEEP TROUGH TAKING HOLD ACROSS
THE NRN ROCKIES...SETTING THE UPPER MIDWEST UP INTO A POTENTIAL
ACTIVE PATTERN.
AT THE SFC...THE COLD FRONT WILL WORK INTO WRN MN BY THIS
AFTERNOON...AND CLEAR THE MPX WI COUNTIES SUN AFTERNOON. THE LOW
CENTER CURRENTLY NEAR THE CO/NEB/KS WILL TRACK ACROSS SOUTH
CENTRAL MN INTO THE WRN TIP OF THE U.P. OF MICH SAT NIGHT/SUN.
HIGH PRESSURE WILL THEN SLIDE ACROSS THE AREA MON/TUE...BEFORE LEE
SIDE TROUGHING REESTABLISHES ITSELF OVER THE NRN HIGH PLAINS WED.
NEXT FRONT STILL ON TAP TO MOVE INTO MN WED NIGHT...AND WITH UPPER
RIDGE AMPLIFYING OVER THE GREAT LAKES THE LATTER HALF OF NEXT
WEEK...THIS FRONT STILL LOOKS TO STALL OUT THEN MEANDER AROUND THE
UPPER MS VALLEY INTO THE HOLIDAY WEEKEND.
THIS MORNING...STRONG WAA OUT AHEAD OF THE ERN SODAK SHORTWAVE
HAS RESULTED IN THE DEVELOPMENT OF AN AREA OF TSRA OVER WRN
MN...RADAR TRENDS MATCH WELL WITH THE IDEA THE RUC IS
SHOWING...WITH THIS WAA AND ASSOCIATED ACTIVITY BASICALLY GOING
DUE NORTH INTO NW MN. DO EXPECT CONDITIONS TO BE FAIRLY QUIET
THROUGH THE MORNING...WITH THE SODAK SHORTWAVE AND COLD FRONT
EXPECTED TO REMAIN WEST OF THE AREA. ONE CAVEAT IS THE LLJ AND
STRONG MOISTURE TRANSPORT IN PLACE ACROSS THE WEST. THIS MAY KEEP
SCT SHRA/TSRA ACTIVITY GOING THROUGH THE MORNING OUT WEST...BUT
DID NOT PLAY THIS IDEA UP TO MUCH IN THE GRIDS. INSTEAD...WAITED
UNTIL THE AFTERNOON TO REALLY GET POPS GOING. BY THEN THE COLD
FRONT WILL BE WORKING INTO WRN MN AS UPPER ENERGY BEGINS TO WORK
IN OVERHEAD. LOOKING AT HIRES REFLECTIVITY FORECASTS...SEEMS TO BE
GOOD AGREEMENT WITH STORMS INITIATING NEAR A RWF TO LONG PRAIRIE
LINE BETWEEN 20 AND 22Z...WITH ACTIVITY WORKING EAST TOWARD THE
I-35 CORRIDOR SHORTLY AFTER 00Z. FORECAST SOUNDINGS AGAIN SHOW
NICE INVERTED-V STRUCTURE THIS AFTERNOON...WITH MLCAPE AGAIN
PUSHING UP TO AROUND 1500 J/KG. IN ADDITION...UNLIKE
YESTERDAY...BULK SHEAR WILL BE IN THE 30-40 KT RANGE...INDICATING
SOME BETTER ORGANIZATION IN CONVECTION IS POSSIBLE. GIVEN LESS
FAVORABLE CONDITIONS MANAGED A FEW 60-70 MPH WIND GUSTS AND GOLF
BALL SIZE HAIL FRIDAY...DO NOT SEE WHY WE DO NOT HAVE A SIMILAR
THREAT FOR SEVERE WEATHER TODAY. IF ANYTHING...WOULD SUSPECT THE
WIND THREAT IS A BIT HIGHER AS BETTER SHEAR AND FAVORABLE
CONDITIONS FOR COLD POOL GENERATION MAY SUPPORT THE DEVELOPMENT OF
ORGANIZED LINE SEGMENTS. BESIDE THE PRECIP...SHOULD BE ANOTHER
WARM DAY...THOUGH NOT EXPECTING WIDESPREAD 90S LIKE FRIDAY. TWO
LIMITING FACTORS FOR HIGHS TODAY WILL BE MORE CLOUD COVER AND
ABOUT A 4 DEG C DROP IN H85 TEMPS. WITH THAT SAID...GUIDANCE HAS
HAD A PRETTY STRONG COLD BIAS IN THIS HEAT WAVE...SO CONTINUED TO
RUN WITH HIGHS A BIT HIGHER THAN WHAT MOST GUIDANCE WOULD SUGGEST.
FOR TONIGHT...WITH THE ARRIVAL OF THE UPPER TROUGH AND ATTENDANT
SFC LOW...WE CONTINUE TO SEE A STRONG SIGNAL FOR THE FORMATION OF
A DEFORMATION BAND OF PRECIP JUST TO THE WEST OF THE SFC LOW
TRACK. BLENDED THE ECMWF/GEM/SREF FOR PRECIP TONIGHT...WITH
HEAVIEST BAND OF PRECIP EXPECTED TO SETUP BETWEEN THE WRN TWIN
CITIES METRO AND MARSHALL/ALEXANDRIA. WITH THE SFC LOW COMING
THROUGH...THIS REALLY SLOWS DOWN THE PRECIP...AND CONTINUED TO
LEAN TIMING OF POPS ON SUN CLOSE TO THE ECMWF. THE ECMWF ALONG THE
NAM/SREF WOULD INDICATE SUNDAY BEING CLOUDY/RAINY FOR MOST OF THE
DAY SUNDAY ACROSS MOST OF THE MN MPX AREA...WITH HIGHS LIKELY NOT
LEAVING THE LOWER 60S. FURTHER EAST...THE COLD FRONT/LOW SHOULD BE
NEAR AN EAU/LADYSMITH LINE BY 18Z...SO SEVERE THREAT CERTAINLY
LOOKS BETTER EAST...THOUGH A MARGINAL TREAT FOR SEVERE WEATHER CAN
NOT BE RULED OUT IN THE FAR EAST.
MON THROUGH WED STILL LOOK DRY AS HIGH PRESSURE SLIDES ACROSS THE
AREA. BIGGEST THING TO WATCH WILL BE LOWS MONDAY MORNING. IF HIGHS
ONLY TOP OUT AROUND 60 IN CENTRAL MN...WE COULD SEE LOWS MONDAY
MORNING MAKE A RUN AT THE UPPER 30S AS HIGH PRESSURES MOVES IN AND
SKIES CLEAR OUT. OTHER THAN THAT...ITS OFF TO WAITING FOR THE NEXT
FRONT WEDNESDAY NIGHT. THE ONLY SIGNIFICANT CHANGE NOTED IN THE
MODELS WITH THIS FRONT IS THE 19.00 ECMWF BASICALLY HALTS ITS EWRD
PROGRESSION ACROSS WRN MN...WITH THE RAIN NOT MAKING IT TO ERN
AREAS. AT ANY RATE...CONTINUED TO MENTION HIGH CHANCE/LIKELY
POPS...ESPECIALLY WEST WED NIGHT. AFTER THAT...THE QUESTION
BECOMES WHERE DOES THE FRONT SET UP. WHERE EVER IT DOES SETUP...NORTH
OF THE BOUNDARY THROUGH THE WEEKEND IS LOOKING LIKE IT COULD BE A
BREEDING GROUND FOR SOME ACTIVE WEATHER...CERTAINLY SOMETHING TO
KEEP A CLOSE EYE ON AS WE HEAD INTO THE BUSY HOLIDAY WEEKEND.
&&
.AVIATION.../12Z TAF ISSUANCE/
TWO MAIN ISSUES...TIMING OF STORMS TODAY/TONIGHT AND EVENTUAL MVFR/IFR
LATER TONIGHT. SIGNIFICANT INFLUX OF MOISTURE IN WESTERN MN AHEAD
OF FRONT. NEXT LOBE OF STORMS JUST ENTERING SW MN ASSOCIATED WITH WEAK
SHORT WAVE. RWF/AXN/STC AT RISK FOR THUNDER LATE THIS MORNING INTO
THE EARLY AFTERNOON FROM THIS. WEAKENING OF SYSTEM COULD RESULT IN
ONLY SHOWERS BY THE TIME IT REACHES EASTERN MN DURING MIDDAY.
BETTER LIFT LOOKS TO ARRIVE LATER THIS AFTERNOON AND HAVE ADDED
THUNDER TO EASTERN MN AND WESTERN WI. CONFIDENCE IS ABOVE AVERAGE
ON EXISTENCE OF STORMS... BUT BELOW AVERAGE ON TIMING...
ESPECIALLY ON STORMS MID AFTERNOON INTO THE EVENING. EXPECT MVFR
CEILINGS AND MAYBE VISIBILITIES TONIGHT WITH POST-FRONTAL RAIN.
BEST CHANCE FOR IFR WILL BE THE KRWF TO KSTC AREA.
KMSP...SHOWERS AND A FEW STORMS IN FAR SWRN MN INTO WESTERN IOWA
AT THIS TIME. THINK THESE WILL WEAKEN BY THE TIME THEY REACH KMSP
AND RESULT IN JUST SOME SCATTERED SHOWERS DURING MIDDAY...WITH A BELOW
AVERAGE CHANCE THAT THERE WILL STILL BE THUNDER BY THE TIME PRECIP
GETS HERE AROUND 18Z-19Z. BETTER CHANCE FOR THUNDER LATE AFTERNOON
WITH NEXT WAVE. TIMING OF INCOMING COLD FRONT LOOKS TO BE AROUND
02Z-06Z FOLLOWED BY MVFR CEILINGS IN PRECIP.
OUTLOOK...
SUN...SHRA AND SOME TSRA POSSIBLE IN THE MORNING WITH MVFR/IFR
POSSIBLE THEN IMPROVING CONDITIONS LATER ON SUNDAY.
SUN NIGHT MON-TUE...VFR.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/TDK
AREA FORECAST DISCUSSION
NWS JACKSON MS
1030 AM CDT SAT MAY 19 2012
.UPDATE...
A MOSTLY DRY FORECAST STILL LOOKS ON TRACK FOR THIS AFTERNOON...BUT HAVE
ADDED MENTION OF ISOLATED TSTMS TO THE FORECAST BASED ON MORNING KJAN
SOUNDING AND LATEST LOCAL-WRF AND HRRR GUIDANCE. EVEN THOUGH SYNOPTIC
FEATURES CONTROLLING CONVECTIVE POTENTIAL TODAY ARE SUBTLE...WEAK
CYCLONIC MID LEVEL FLOW IS IN PLACE WITH H500 TEMPERATURES ~ -12 C
AND ACCAS IS APPARENT OVER SOUTHWEST MS. DEEP LAYER MOISTURE IS
LIMITED WITH PRECIPITABLE WATER ~1.2 IN...BUT SFC DEWPOINTS AROUND
60F AND SFC TEMPS APPROACHING 90F WILL YIELD SFC-BASED CAPE EXCEEDING
2000 J/KG. HIGH RESOLUTION GUIDANCE SHOWING STRAY TSTM POTENTIAL
LOOKS REASONABLE AND WILL RAISE POPS SLIGHTLY. SHOULD A FEW TSTMS
DEVELOP...30-40 MPH WIND GUSTS WOULD BE A POSSIBILITY GIVEN DEEP SUB-
CLOUD LAYER AND STEEP LOW LEVEL LAPSE RATES DCAPE VALUES > 1000 J/KG.
AS SUGGESTED EARLIER THIS MORNING...THE AREAS ALONG AND NW OF THE
NATCHEZ TRACE PARKWAY ARE MOST FAVORABLE FOR GETTING STORMS. THE
UPDATED AVIATION DISCUSSION IS BELOW. /EC/
&&
.PREV DISCUSSION... /ISSUED 359 AM CDT SAT MAY 19 2012/
DISCUSSION...SHORT TERM(TODAY THROUGH SUNDAY NIGHT) THIS WEEKEND
WILL BE CHARACTERIZED BY WARM TEMPERATURES AND MAINLY DRY CONDITIONS.
THE REGION SITS UNDER HIGH PRESSURE AT THE SFC WITH A DEVELOPING LOW
PRESSURE SYSTEM ACROSS THE PANHANDLE OF TEXAS. ALOFT...THE REGION
SITS BETWEEN BROAD TROUGHING TO THE EAST AND BUILDING RIDGING TO THE
WEST.
CONDITIONS TODAY AND SUNDAY WILL BE SIMILAR TO PREVIOUS DAYS WITH
CONTINUED WARM SUMMERLIKE TEMPERATURES...PERHAPS JUST A DEGREE OR
TWO WARMER EACH DAY INTO THE UPPER 80S AND LOWER 90S. RAIN CHANCES
WILL BE RATHER SLIM GIVEN INCREASED RIDGING IN THE WEST...LOW
MOISTURE PER MODEL PW VALUES(THOUGH THAT HAS NOT SEEMED TO MATTER
THE LAST FEW DAYS WITH VALUES LESS THAN 1 INCH AND STILL GENERATING
SHOWERS)...AND NO DISCERNIBLE FORCING MECHANISM OTHER THAN DAYTIME
HEATING. I CANNOT COMPLETELY RULE OUT SOME RAIN SHOWERS BUT
PINPOINTING EXACTLY WHERE WILL BE DIFFICULT. SOME WRF AND HI-RES
MODELS INDICATE MORE SHOWER ACTIVITY IN THE WEST THIS AFTERNOON BUT
THIS IS ALSO WHERE THE BETTER RIDGING EXISTS. OVERNIGHT LOWS WILL BE
IN THE UPPER 50S/LOWER 60S ACROSS THE REGION.
COME SUNDAY NIGHT...A COLD FRONT WILL CONTINUE TO MAKE ITS WAY SOUTH
TOWARD THE AREA. MOST OF THE RAIN SHOULD REMAIN OUT OF THE CWA
THROUGH THE NIGHT BUT CLOSER TO DAYBREAK THERE COULD BE SOME SLIGHT
CHANCES FOR THE DELTA AND HAVE INCREASED POPS IN THIS REGION JUST A
LITTLE TO INTRODUCE SLIGHT CHANCE WORDING FOR THE PRE-DAWN HOURS./28/
LONGER TERM(MONDAY THROUGH SATURDAY)...SEVERAL FACTORS COMING
TOGETHER FOR AT LEAST DECENT RAIN CHANCES MONDAY THROUGH TUESDAY TO
START THE WORK WEEK. A MID-UPPER LEVEL TROUGH DRIVES SEWD DOWN THE MO
RIVER VALLEY INTO THE TN VALLEY BY MONDAY NIGHT. THE TROUGH PUSHES AN
AXIS OF 1.5 INCH PWAT AIR ALONG THE INCOMING FRONT THAT COMBINES WITH
14-1600J/KG MLCAPES AND NEAR 7C 7-500MB LAPSE RATES FOR A COUPLE OF
ROUNDS OF SCATTERED TSRA MOSTLY TRIGGERED BY DAYTIME HEATING. THE
FIRST ROUND GETS GOING ACROSS THE I-40 CORRIDOR EARLY MONDAY MORNING
AND SAGS INTO OUR NRN CWFA BY MIDDAY WHEN K INDEXES REACH THE M30S.
RATHER WEAK LOW AND MID LEVEL FLOW OF 15-25KTS WILL LIMIT INTENSITIES
OF THE THESE SEWD- MOVING STORMS HOWEVER INTERACTING PREFRONTAL
BOUNDARIES IN A RIBBON OF 330K THETA E 850MB AIR COULD PRODUCE A FEW
STRONG STORMS MONDAY AFTERNOON GENERALLY N OF I-20. WILL MENTION THIS
POTENTIAL IN THE HWOJAN.
THEN...THE LEFTOVER ACTIVITY GRADUALLY WEAKENS MONDAY NIGHT BUT AT
LEAST SOME SHRA PROBABLY PERSISTING. ONCE TUESDAY ARRIVES...THE BEST
INSTABILITY REDEVELOPS ACROSS OUR SRN SECTIONS MAINLY S OF HIGHWAY 84
DURING THE MIDDAY AND AFTERNOON HOURS. THE COOLEST DAYTIME MAXES IN
THE M-U80S FOR THE COMING WEEK SHOULD OCCUR AND AS A RESULT...WILL
KEEP HIGHER POPS SHIFTED SWD TO THOSE LOCATIONS WITH THE FRONT
PUSHING ALL THE WAY TO NEAR THE COAST TUESDAY EVENING. DRYING AIR
SINKS INTO OUR N PORTIONS WHERE PWATS DROP BELOW 1 INCH LATE TUESDAY
THROUGH TUESDAY NIGHT.
THE AXIS OF HIGHER PWATS NEAR 1.4 INCHES PIVOTS BACK INTO THE REGION
WEDNESDAY AFTERNOON HELPING TO SET OFF AT LEAST ISOLATED SHRA/TSRA.
THE RETURNING WARM FRONT FEATURES NEAR 2K J/KG MLCAPES AND 335K THETA
E 850MB AIR BUT GENERALLY EVEN WEAKER WIND PROFILES. WILL KEEP SMALL
POPS FOR DAYTIME HEATING OF THE MOISTURE RETURN AS LOW LEVEL
CONVERGENCE REMAINS WEAK. THEREAFTER...BUILDING MID LEVEL RIDGE
ACROSS THE MID SOUTH AND TN VALLEY YIELDS 592DM 500MB HEIGHTS AND
WARMING LOW LEVELS THAT PUSH 850MB TEMPS TO THE 17-19C RANGE FRIDAY
AND SATURDAY. OVERNIGHT LOWS WILL STAY PREDOMINANTLY IN THE 60S WHILE
EVEN MORE DAYTIME LOWER 90S SHOULD BE IN THE PICTURE JUST IN TIME
FOR THE MEMORIAL DAY WEEKEND./40/
&&
.AVIATION...ISOLATED SHOWERS NOT OUT OF THE QUESTION AGAIN TODAY BUT
CONFIDENCE IN AFFECTING A TAF SITE IS LOW AND WILL NOT BE INCLUDED IN
THE FORECAST AT THIS POINT. EXPECT SCATTERED CUMULUS BASES DEVELOPING
MIDDAY THROUGH AFTERNOON IN THE 6 TO 9 KFT RANGE. WINDS WILL BE FROM
THE EAST THROUGH SOUTH AT 5 TO 10 KTS. TONIGHT WILL SEE SOME MORE
SCATTERED MIST (MVFR LEVEL) LATE THAT WILL DISSIPATE BY 9 AM SUNDAY
MORNING. CHANCES FOR RAIN SUNDAY AFTERNOON AGAIN APPEAR GENERALLY LOW
WITH WINDS LIGHT. /BB/
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DENVER CO
1207 PM MDT SAT MAY 19 2012
.SHORT TERM...THE UPPER TROUGH IS RIGHT OVER THE CWA AT THIS
TIME...WITH THE BEST CONVECTION OVER THE FOOTHILLS AND IMMEDIATE
PLAINS. WITH THE AMOUNT OF CLOUD COVER EXPECTED...WILL LOWER HIGH
TEMPERATURES A BIT. WILL MAKE MINOR ADJUSTMENTS TO POPS WITH REAL
CONDITIONS IN MIND.
.AVIATION...WILL HANG ON TO PRECIPITATION AND LOWER CEILINGS A BIT
LONGER THIS AFTERNOON WITH CURRENT SITUATION IN MIND. WILL GET
BACK TO NORMAL DIURNAL WIND PATTERNS AROUND 06Z TONIGHT. CEILINGS
WILL GET ABOVE 5000 AGL BETWEEN 03Z AND 04Z THIS EVENING.
&&
.PREV DISCUSSION... /ISSUED 353 AM MDT SAT MAY 19 2012/
SHORT TERM...WATER VAPOR IMAGERY SHOWING UPPER LOW NOW MOVING
ACROSS WESTERN COLORADO WITH SCATTERED SHOWERS INCREASING ACROSS
THE NORTHERN MOUNTAINS ATTM. RUC QG ANALYSIS SHOWING WEAK TO MODERATE
ASCENT NOW INTO THE MOUNTAINS AND THIS WILL SPREAD OVER INTO THE
NORTHEAST PLAINS THIS MORNING. MEANWHILE...COLD FRONT HAS MOVED
THROUGH ALL OF NORTHEAST COLORADO WITH SHALLOW N-NE UPSLOPE FLOW
DEVELOPING OVER THE PAST FEW HOURS. SURFACE DEWPOINTS HAVE BEEN
RISING INTO THE MID 40S AND WE SHOULD START SEEING SOME STRATUS
DEVELOPING BETWEEN 09-12Z ACROSS THE FRONT RANGE GIVEN THE ASCENT
AND UPSLOPE DEVELOPING. SHORT RANGE MODELS STILL SHOWING A
MOISTENING AIRMASS THIS MORNING WITH SHOWERS SPREADING OUT OVER THE
PLAINS. CURRENT LIKELY POPS STILL SEEM REASONABLE BUT AMOUNTS
STILL LOOK TO BE ON THE LOW SIDE AS THE TROF WILL MOVING MOVING
RIGHT ALONG AND NOT A TON OF DEEP MOISTURE DEVELOPING WITH THIS
QUICK MOVING SYSTEM. TEMPERATURES MUCH COOLER TODAY WITH READINGS
ONLY IN THE 50S AND LOWER 60S OVER THE PLAINS. MAY SEE SOME LIGHT
SNOW ACCUMULATIONS IN THE MOUNTAINS AND WITH THE MORE SCATTERED
NATURE DON`T SEEM MUCH MORE THAN 2-4 INCHES IN THE HIGHER
MOUNTAINS. POSSIBLY A BIT MORE IN THE HEAVIER EMBEDDED CONVECTIVE
SNOW SHOWER. BOTH NAM/GFS SEEM A BIT HIGH WITH LIQUID AMOUNTS OVER
AN INCH IN MOUNTAINS AND HIGHER EAST SLOPES.
THE LOW WILL HAVE MOVED INTO WESTERN KANSAS BY LATE IN THE DAY
WITH SUBSIDENCE SPREADING OVER THE PLAINS THIS AFTERNOON. HENCE A
DECREASE IN SHOWER ACTIVITY AND ENDING IN MOST LOCALES DURING THE
EVENING HOURS. GRADUAL CLEARING OVERNIGHT ACROSS THE ENTIRE AREA.
LONG TERM...NORTHEAST COLORADO UNDER WEST-NORTHWESTERLY FLOW ALOFT
WITH THE SHORTWAVE TROUGH CONTINUING ITS EASTWARD PROGRESSION
ACROSS THE CENTRAL GREAT PLAINS DURING THE DAY SUNDAY. SHOULD SEE
A WARMER DAY WITH A 2C WARMING AT 700 MBS. MODELS ALSO SHOW
S-SELY SFC WINDS ON THE PLAINS STEADILY STRENGTHENING DURING THE
DAY WHICH AIDS IN TRANSPORTING INCREASINGLY HUMID AIR NORTHWARD
UP ALONG THE FRONT RANGE. STEEP LAPSE RATES DUE TO STG DAYTIME
HEATING AND THE ARRIVAL OF THIS MOISTURE SHOULD SUPPORT AT LEAST
ISOLATED T-STORM DEVELOP OVER AND NEAR THE FRONT RANGE DURING THE
AFTERNOON AND EVENING HOURS. STORMS MOVING OUT ACROSS THE PLAINS
MAY LINGER WELL INTO THE EVENING WITH THIS MOIST SELY INFLOW.
ON MONDAY...FCST AREA BENEATH A STG 500 MB HIGH PRESSURE RIDGE WITH
TEMPERATURES ALOFT CONTINUING TO WARM. A BRISK SOUTHERLY LOW-
LEVEL FLOW ON THE PLAINS WILL CONTINUE TO ADVECT MOISTURE UP INTO
THE AREA. BY AFTERNOON...MODELS SHOW AN 850-700 THETA-E RIDGE AXIS
ALIGNED FM COLORADO SPRINGS TO JULESBURG. ALONG THIS AXIS SFC
BASED CAPES PROGGED IN THE 1200-2000 KG/J RANGE BY LATE IN THE
DAY. HOWEVER STG WARMING ALOFT AND WEAK CIN POSSIBLY ENOUGH TO
SUPPRESS CONVECTION. FOR NOW WILL LEAVE OUT MENTION OF T-STORMS ON
THE PLAINS...BUT CAN/T RULE THEM OUT ENTIRELY. WHEREAS WILL
MENTION AT LEAST A SLIGHT CHANCE OF T-STORMS OVER AND NEAR THE
FRONT RANGE FOR LATE IN THE DAY. GOING FOR TEMPERATURES ON MONDAY
IN THE LOWER-MID 80S AT LOWER ELEVATIONS WITH UPPER 50S- 70S IN
THE HIGH COUNTRY.
BY TUESDAY...UPPER RIDGE MOVES EAST OF THE STATE PLACING THE AREA
UNDER INCREASING SOUTHWESTERLY FLOW ALOFT. A DRIER MID-LEVEL WITH
SUBSIDENCE ON THE SOUTH SIDE OF AN APPROACHING UPPER AIR TROUGH
SHOULD RESULT IN PLENTY OF SUNSHINE DURING THE MORNING HOURS.
COMBINATION OF UNSEASONABLY WARM TEMPERATURES...LOW HUMIDITY AND
AND STEEP LAPSE RATES WILL LIKELY INCREASE THE WILDLAND FIRE
DANGER IN MANY AREAS. NOT UNTIL LATE IN THE DAY WHEN THE UPPER
TROUGH NEARS WILL SEE CONVECTION...MOST OF WHICH SHOULD BE
CONFINED TO THE HIGHER TERRAIN NORTH OF I-70. SHOULD SEE ANOTHER
DAY OF VERY WARM TEMPERATURES WITH HIGHS PUSHING THE 90 DEG MARK
ON THE PLAINS.
BY WEDNESDAY TEMPERATURES TURN COOLER WITH PASSAGE OF THE UPPER
TROUGH AND PASSAGE OF A COLD FRONT DURING THE DAY. SHOULD SEE THE
CHANCE FOR SHOWERS AND T-STORMS ALSO INCREASE. THE UPPER TROUGH
PASSES TO THE EAST OVERNIGHT RESULTING IN A SLIGHT MODERATION IN
TEMPERATURE AND A REDUCED CHANCE IN PRECIP. FOR LATER IN THE
WEEK...SHOULD SEE STEADY WARMING WITH THE RETURN OF RIDGING.
AVIATION...CEILINGS LOWERING BY DAYBREAK WITH MAINLY MVFR/ILS
APPROACHES THROUGH THIS MORNING WITH RAIN SHOWERS AND THEN
IMPROVING TRENDS DURING THE AFTERNOON. SURFACE WINDS SHOULD REMAIN
N-NE TODAY BEFORE SHIFTING SE-S BY LATER THIS EVENING AND A RETURN
TO DRAINAGE.
HYDROLOGY...RAINFALL AMOUNTS LOOK TO BE IN THE QUARTER TO HALF
INCH RANGE FOR TODAY WITH RAINFALL RATES GENERALLY A TENTH OF AN
INCH PER HOUR OR LESS WITH THE SHOWERS. ANY FLOODING POTENTIAL IN THE
BURN AREAS SEEM LOW.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RJK/ENTREKIN
LONG TERM....BAKER
AVIATION...RJK/ENTREKIN
AREA FORECAST DISCUSSION
NWS MIAMI FL
147 PM EDT SAT MAY 19 2012
.AVIATION...
CONVECTION HAS STARTED ACROSS THE SOUTH FLORIDA PENINSULA. THE
MOST ACTIVE REGION IS ACROSS THE EASTERN HALF WITH ALL TERMINALS
ASSIGNED VCTS. FOR TERMINAL KAPF...ALSO ASSIGNED VCTS WITH
CONVECTION STARTING JUST INLAND OF THE TERMINAL. THERE IS THE
POTENTIAL FOR SOME STRONG TO SEVERE THUNDERSTORMS THIS AFTERNOON
WITH THE EAST COAST TERMINALS BEING THE MOST LIKELY TO BE AFFECTED
WITH PERIODS OF MVFR TO IFR CONDITIONS POSSIBLE WITH OCCURRENCE OF
ANY SHOWERS OR THUNDERSTORMS. CONVECTION WILL LIKELY LINGER INTO
EVENING HOURS AND SUBSIDE THEREAFTER.
60
60
&&
.PREV DISCUSSION... /ISSUED 1015 AM EDT SAT MAY 19 2012/
UPDATE...UPDATED FORECAST PACKAGE TO MENTION POSSIBLE STRONG TO
SEVERE STORMS THIS AFTERNOON. 12Z SOUNDING PARAMETERS ALMOST
IDENTICAL TO FRIDAY`S VALUES. PW=1.72 INCHES, 500 MB TEMP AROUND
-10C TO -11C AND THE LIKELIHOOD OF WET MICROBURSTS AND LARGE HAIL. 850 MB
ANALYSIS ALSO SHOWS A WEAK TROUGH MOVING SLOWLY EASTWARD ACROSS
SOUTH FLORIDA. THIS COMBINED WITH PLENTY OF HEATING AND LEFT-OVER
OUTFLOW BOUNDARIES FROM YESTERDAY`S CONVECTIVE ACTIVITY WILL LEAD TO
THUNDERSTORMS DEVELOPING JUST ABOUT ANYWHERE IN S. FLORIDA. HOWEVER,
WESTERLY MID/UPPER LEVEL FLOW MAY STEER ANY STORM EASTWARD TOWARD
THE EASTERN INTERIOR AND EASTERN METRO AREAS.
AVIATION...
THE WINDS WILL REMAIN LIGHT EARLY THIS MORNING BEFORE BECOMING
SOUTHEAST AT 5 TO 10 KNOTS AFTER 13Z TODAY. THE ONLY EXCEPTION TO
THIS IS AT KAPF WHERE THE WINDS WILL BE EASTERLY THIS MORNING BEFORE
SWINGING TO A WESTERLY DIRECTION AROUND 16Z TODAY...DUE TO THE WEST
COAST SEA BREEZE DEVELOPING AND PUSHING INLAND. CONVECTION IS
EXPECTED ACROSS THE PENINSULA TODAY...WITH VCSH ASSIGNED ALL
TERMINALS THROUGH 15Z AND VCTS ASSIGNED ALL TERMINALS AT 16Z.
MAINLY VFR CONDITIONS EXPECTED TO PREVAIL ALL TERMINALS THROUGH
15Z AND STARTING AT 16Z PERIODS OF SUB-VFR CONDITIONS AND BRIEF
PERIODS OF IFR CONDITIONS POSSIBLE WITH OCCURRENCE OF SHOWERS
AND/OR THUNDERSTORMS.
60
PREV DISCUSSION... /ISSUED 347 AM EDT SAT MAY 19 2012/
SHORT RANGE (TODAY-MONDAY)...
RECENTLY ANIMATED WATER VAPOR LOOP SHOWED A BROAD TROUGH CENTERED
OVER THE SOUTHEAST WITH A NOTABLE SHORTWAVE TROUGH EXTENDING
SOUTHWEST FROM THE FLORIDA PANHANDLE TO THE CENTRAL GULF AND PLENTY
OF MID/UPPER MOISTURE SPREADING EAST-NORTHEAST ACROSS SOUTH
FLORIDA...THE KEYS AND FLORIDA STRAITS. THE LATEST SURFACE ANALYSIS
SHOWED A WEAKNESS WITHIN THE SUBTROPICAL RIDGE ACROSS THE LOCAL AREA
WITH A TROUGH OR FRONTAL BOUNDARY EXTENDING SOUTHWEST FROM A LOW
PRESSURE CENTERED OFF THE CAROLINA COAST TO CENTRAL FL.
THE MODELS HAVE INITIALIZED WELL WITH THIS SYNOPTIC PATTERN AND
INDICATE ANOTHER POTENTIALLY ACTIVE DAY ACROSS THE FLORIDA
PENINSULA...SIMILAR TO YESTERDAY. THE AFOREMENTIONED SHORTWAVE
TROUGH WILL ROTATE EASTWARD AROUND THE BASE OF THE UPPER TROUGH
AND MOVE ACROSS THE AREA TODAY FROM WEST TO EAST...WHICH WILL LEAD
TO DECREASING UPPER HEIGHTS AND SOME COOLER MID-LEVEL AIR (-10 TO
-11 C 500 MB TEMPS) SPREADING OVER THE AREA THIS AFTERNOON. THIS
COMBINED WITH A WEAK SFC TROUGH AND LOW-LEVEL CONVERGENCE
ASSOCIATED WITH THE EAST/WEST COAST SEA BREEZES WILL BE ENOUGH TO
INITIATE ANOTHER ROUND OF AFTERNOON CONVECTION. THE ONE DIFFERENCE
TODAY COMPARED TO YESTERDAY IS THAT THE LOW-LEVEL FLOW WILL HAVE
MORE OF AN EASTERLY COMPONENT...WHICH SHOULD HELP CONCENTRATE THE
CONVECTIVE ACTIVITY OVER THE INTERIOR SECTIONS INITIALLY. THE
LATEST HRRR MODEL REFLECTIVITIES LINE UP WELL WITH THIS AND
GENERALLY INDICATE CONVECTION BEGINNING BY 18Z OVER THESE INTERIOR
LOCATIONS. WITH THE DRIER/COOLER MID-LEVEL AIR EXPECTED...THE MAIN
THREATS WITH THE STRONGER STORMS THAT DEVELOP WILL BE DAMAGING
STRAIGHT LINE WINDS AND HAIL.
TONIGHT THROUGH MONDAY...SIMILAR CONDITIONS WILL BE EXPECTED EACH
DAY WITH SCATTERED AFTERNOON SHOWERS/TSTMS DEVELOPING OVER THE
INTERIOR SECTIONS ASSOCIATED WITH THE PERSISTENT UPPER TROUGH AND
AFTERNOON SEA BREEZES.
LONG RANGE (MONDAY NIGHT-FRIDAY)...
THE GFS/GFS ENSEMBLE MEAN/ECMWF GENERALLY ALL MAINTAIN THE
MID/UPPER TROUGH OVER THE SOUTHEAST REGION WITH DRY MID/UPPER
WESTERLY FLOW CONTINUING ACROSS THE FL PENINSULA. AT THE
SURFACE...ALTHOUGH THERE REMAINS SOME DIFFERENCES NOTED BETWEEN THE
MODEL SOLUTIONS...THE GFS/ECMWF GENERALLY INDICATE A WEAK TROUGH
EXTENDING NORTHEAST FROM A BROAD LOW CENTERED OVER THE WESTERN
CARIBBEAN ACROSS THE FLORIDA STRAITS...WHICH MAY HELP CONCENTRATE
ANY DEEP MOIST CONVECTION JUST SOUTH OF OUR LOCAL AREA ACROSS THE
KEYS AND STRAITS. OTHERWISE...MORE OF A SEASONAL PATTERN WITH 20-30
PERCENT RAINFALL CHANCES EACH DAY ASSOCIATED WITH THE AFTERNOON SEA
BREEZES WILL REMAIN IN THE FORECAST. TEMPERATURES WILL REMAIN AROUND
NORMAL THROUGH THIS TIME WITH HIGHS IN THE UPPER 80S AND LOWS IN THE
LOWER 70S.
MARINE...
A WEAK PRESSURE GRADIENT WILL RESULT IN LIGHT EASTERLY WINDS
AND LOW SEAS CONTINUING THROUGH THE WEEKEND AND INTO THE UPCOMING
WEEK. SCATTERED SHOWERS AND THUNDERSTORMS COULD LEAD TO BRIEF
PERIODS WITH LOCALLY HIGHER WINDS AND SEAS.
AVIATION...
THE WINDS WILL REMAIN LIGHT EARLY THIS MORNING BEFORE BECOMING
SOUTHEAST AT 5 TO 10 KNOTS AFTER 13Z TODAY. THE ONLY EXCEPTION TO
THIS IS AT KAPF WHERE THE WINDS WILL BE EASTERLY THIS MORNING
BEFORE SWINGING TO A WESTERLY DIRECTION AROUND 17Z TODAY...DUE TO
THE WEST COAST SEA BREEZE DEVELOPING AND PUSHING INLAND.
THE WEATHER WILL ALSO REMAIN DRY THROUGH 13Z TODAY...BEFORE VCSH
FOR ALL TAF SITES BETWEEN 13Z AND 17Z. THUNDERSTORMS WILL THEN
DEVELOP THIS AFTERNOON ALONG THE SEA BREEZE AND PUSH SLOWLY INLAND
OVER THE COAST AREAS...WHILE THE WEST COAST SEA BREEZE PUSHES MORE
INLAND. SO WILL INTRODUCE VCTS FOR THE EAST COAST TAF SITES
BETWEEN 17Z AND 23Z TODAY...WHILE THE KAPF TAF SITE REMAINS IN THE
VCSH FOR THE AFTERNOON HOURS. THE ACTIVITY WILL THEN DISSIPATE
BETWEEN 00Z AND 02Z TONIGHT OVER ALL OF THE TAF SITES...AS THE
HEATING OF THE DAY IS LOST. SO AFTER 02Z TONIGHT THE WEATHER WILL
BE DRY AGAIN.
THE CEILING AND VIS WILL REMAIN IN THE VFR CONDITIONS THROUGH
TODAY...DUE TO THE UNKNOWN TIMING OF THE SHOWERS AND THUNDERSTORMS
FOR TODAY.
FIRE WEATHER...
SOME STRONG TO SEVERE STORMS ARE POSSIBLE THIS AFTERNOON OVER
SOUTH FLORIDA ESPECIALLY WHERE THE EAST AND WEST COAST SEA BREEZES
COLLIDE OVER THE INTERIOR AREAS. THE PRIMARY IMPACTS FROM THE
STRONGEST STORMS WILL BE FREQUENT LIGHTNING STRIKES...GUSTY
WINDS...HAIL UP TO QUARTER SIZE...AND HEAVY RAINFALL. THE BEST
TIME TO SEE THE STORMS WILL IN THE AFTERNOON AND EARLY EVENING HOURS.
THE RELATIVE HUMIDITIES TODAY WILL REMAIN ABOVE THE 35 PERCENT
CRITICAL VALUE..AS THE DISPERSION INDEX WILL RANGE FROM THE 20S
INTERIOR AREAS TO 40 ALONG THE METRO AREAS. THE DISPERSION INDEX
FOR TONIGHT WILL BE LESS THAN 5. THIS MEANS THAT THE MIXING FOR
TODAY IS IN THE FAIR TO GOOD RANGE...WHILE TONIGHT IT IS IN THE
VERY POOR RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 71 85 73 86 / 40 30 20 30
FORT LAUDERDALE 72 86 74 86 / 40 30 20 30
MIAMI 73 86 73 87 / 40 30 20 30
NAPLES 70 86 71 87 / 20 40 20 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...47/RGH
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS WICHITA KS
314 PM CDT SAT MAY 19 2012
.DISCUSSION...
SYNOPSIS...SURFACE LOW PRESSURE WAS CENTERED NEAR GREAT BEND AT
18Z. THIS LOW WAS PART OF A COLD FRONT THAT EXTENDED FROM CENTRAL
MINNESOTA /AND AREAS FURTHER NORTH/...TO THE TEXAS PANHANDLE.
A STRONG UPPER LEVEL DISTURBANCE WAS ADVANCING NORTHEASTWARD ACROSS
SOUTHWEST NEBRASKA. THIS WILL BRING DESTABILIZING COOLER AIR IN THE
MID LEVELS TO THE REGION...CAUSING SHOWERS AND THUNDERSTORMS TO
DEVELOP ALONG THE FRONT. THESE ARE ALSO A BIG PART OF THE STORMS
ONGOING ACROSS WESTERN KANSAS AND WESTERN NEBRASKA. AS OF
1945Z...THE LEADING EDGE OF THIS CAN BE SEEN WELL ON WATER VAPOR
MOVING ACROSS WESTERN KANSAS.
TONIGHT...
THE FRONT WILL CONTINUE MOVING SOUTHEAST THIS EVENING. RUC SHOWING
SIGNIFICANT COLD ADVECTION ONGOING WITH THE APPROACHING
DISTURBANCE. DURING THE DAY...THE CONVERGENCE ALONG THE FRONT HAS HAD A
HARD TIME GETTING GOING AS THE WINDS HAVE VEERED AHEAD OF THE
FRONT. THIS HAS ADDED TO THE UNCERTAINTY OF WHEN CONVECTION IS
EXPECTED TO DEVELOP...BUT SHOULD BE BY 23Z. 0-6KM SHEAR IS MARGINAL
FOR ORGANIZED CONVECTION...WITH VALUES RANGING FROM 30-35 KNOTS.
THAT SAID...THERE IS ENOUGH INSTABILITY FOR SOME OF THE STORMS TO
BECOME SEVERE.
SUNDAY...THE FRONT SHOULD MAKE IT WELL INTO SOUTHEAST KANSAS. WITH
THE MAIN UPPER LEVEL SUPPORT FAR REMOVED FROM THE FRONT...ORGANIZED
SEVERE STORMS LOOK UNLIKELY AT THIS TIME...THOUGH SOME SCATTERED
STORMS EXPECTED.
MONDAY-SATURDAY...
HIGH PRESSURE WILL REMAIN ACROSS THE REGION THROUGH TUESDAY. THE
FRONT THAT JUST MOVED THROUGH WILL RETREAT NORTHWARD AS A WARM
FRONT. LEE CYCLOGENESIS TAKES PLACE AND BY WEDNESDAY...STRONG
SOUTHWESTERLY WINDS DEVELOP AGAIN AT THE SURFACE. THIS WILL ALL
RESULT IN A WARMING TREND IN THE MIDDLE AND LATTERN PORTION OF THE
WEEK. BY FRIDAY...A DEEP UPPER LEVEL TROUGH DEVELOPS OVER THE
PACIFIC COAST WITH RIDGING OVER THE SOUTHEAST. THIS WILL KEEP ALL
OF THE SIGNIFICANT PRECIPITATION WELL TO THE NORTH.
COOK
&&
.AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
MAIN HAZARDS: WINDS AHEAD OF/BEHIND COLD FRONT...AND THUNDERSTORMS.
S-SWRLY GUSTS 25-35KT WILL PERSIST AHEAD OF FRONT THIS PM/EARLY
EVE. COLD FRONT SHOULD REACH RSL AROUND 20-21Z...SLN/HUT
01-02Z...AND ICT ~03-04Z. SCATTERED-BROKEN LINE OF THUNDERSTORMS
SHOULD DEVELOP ALONG THE FRONT LATE THIS PM/EVE WHICH COULD
PRODUCE OUTFLOW AHEAD OF ACTUAL FRONT. WIND GUSTS 40-50 KT AND
HAIL WOULD BE THE MAIN THREATS FROM THESE STORMS. WILL CARRY TEMPO
TS AT HUT/SLN SITES WITH HIGHEST CONFIDENCE OF STORMS AFFECTING
THOSE SITES...AND VCTS AT ICT. WIND SHIFT TO NW WITH SOME GUSTS
20-25 KT THIS EVE IN CENTRAL/SOUTH CENTRAL KS.
JMC
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 58 79 57 80 / 50 20 10 0
HUTCHINSON 56 78 54 80 / 50 10 0 0
NEWTON 57 77 53 78 / 50 20 10 0
ELDORADO 59 78 54 79 / 40 20 10 0
WINFIELD-KWLD 61 79 58 80 / 40 30 20 10
RUSSELL 52 77 51 81 / 20 10 0 0
GREAT BEND 53 78 52 81 / 20 10 0 0
SALINA 56 78 51 80 / 50 10 0 0
MCPHERSON 57 77 52 79 / 50 10 0 0
COFFEYVILLE 65 81 59 79 / 30 40 30 10
CHANUTE 64 79 57 78 / 40 40 10 10
IOLA 64 78 57 77 / 30 40 10 10
PARSONS-KPPF 65 80 58 78 / 30 40 20 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
619 PM EDT SAT MAY 19 2012
.SYNOPSIS...
HIGH PRESSURE WILL ALLOW FOR DRY AND UNSEASONABLY WARM WEATHER TO
CONTINUE INTO EARLY MONDAY. THE CHANCE OF SHOWERS AND THUNDERSTORMS
WILL RETURN AS A LOW PULLS MOISTURE INTO THE AREA FROM THE SOUTHEAST
AND A FRONTAL BOUNDARY APPROACHES FROM THE WEST.
&&
.NEAR TERM /THROUGH SUNDAY/...
MINOR CHANGES TO PREVIOUS FORECAST, INCREASED OVERNIGHT LOWS A
COUPLE OF DEGREES AND MADE TWEAKS TO CLOUD COVER.
PREVIOUS DISCUSSION...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A 500MB RIDGE
EXTENDING FROM THE THE OHIO VALLEY INTO NEW ENGLAND WITH ITS
ASSOCIATED WEAK ANTI-CYCLONIC FLOW CENTERED ACROSS THE OHIO
VALLEY. MEANWHILE, A CLOSED LOW IS LOCATED OFF THE CAROLINA COAST.
AT THE SURFACE, A BROAD AREA OF HIGH PRESSURE IS CENTERED ACROSS
THE NORTHEAST, EXTENDING SOUTHWESTWARD INTO THE REGION.
THE RIDGE WILL SHIFT FURTHER NORTHEAST TONIGHT AND TOMORROW,
ALLOWING FOR DRY WEATHER TO CONTINUE WITH UNSEASONABLY WARM
HIGH TEMPS. SKIES WILL BE MOSTLY CLEAR THROUGH THIS
PERIOD, ASIDE FROM SOME HIGH CIRRUS SPILLING INTO THE AREA AHEAD
OF THE LOW TO THE SOUTHEAST. DESPITE TEMPS IN THE LOW TO MID 80S
FOR HIGHS, DRY AIR IN PLACE ALONG WITH NEAR CALM WINDS AND MOSTLY
CLEAR SKIES OVERNIGHT WILL ALLOW FOR ANOTHER NIGHT OF DECENT
RADIATIONAL COOLING. THUS, LOWS ARE A MAV/MET BLEND, DROPPING TO
NEAR NORMAL SEASONAL VALUES, IN THE LOW TO MID 50S ACROSS THE
AREA. THE GFS INDICATES 850 TEMPS AROUND 15C TOMORROW. THIS WILL
CONTRIBUTE TO YET ANOTHER DAY WITH HIGHS 10-15 DEGREES ABOVE
NORMAL, RANGING FROM THE MID 80S ACROSS THE LOWLANDS TO THE MID
70S ACROSS THE EASTERN RIDGES.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
GFS/ECMWF INDICATE THE RIDGE AXIS BECOMING PINCHED OFF SUNDAY NIGHT
INTO MONDAY AS THE UPPER LOW MOVES INTO VIRGINIA AND A TROUGH MOVES
INTO THE UPPER MIDWEST. THE CLOSED LOW WILL SERVE TO DRAW MOISTURE
INTO THE AREA FROM THE ATLANTIC. WITH THIS IN MIND, THE CHANCE OF
SHOWERS BEGINS SOUTHEAST OF PITTSBURGH ON MONDAY MORNING. IN
ASSOCIATION WITH THE TROUGH, A FRONTAL BOUNDARY WILL CROSS THE OHIO
VALLEY ON MONDAY AFTERNOON. INCREASING MOISTURE AND INSTABILITY
AHEAD OF THIS FEATURE WILL LEAD TO THE CHANCE OF SHOWERS AND
THUNDERSTORMS MONDAY AFTERNOON THROUGH THE EVENING. INCREASED
CLOUD COVERAGE AND COOLER TEMPS ALOFT ASSOCIATED WITH THE LOW
APPROACHING FROM THE SOUTHEAST WILL ALLOW FOR A SLIGHT COOLER DAY
ON MONDAY, WITH HIGH TEMPS AT 5 TO 10 DEGREES ABOVE NORMAL,
RANGING FROM THE LOWER 80S ACROSS EASTERN OHIO TO NEAR 70 ACROSS
THE EASTERN RIDGES.
SOME MODEL UNCERTAINTY ENTERS THE FORECAST IN REGARDS TO THE TROUGH
MOVING INTO THE AREA FROM THE UPPER MIDWEST. ECMWF/NAM SOLUTIONS
MERGE THE UPPER LOW TO THE SOUTHEAST WITH THIS FEATURE INTO A MORE
AMPLIFIED TROUGH ACROSS THE AREA. MEANWHILE, THE GFS MOVES THE UPPER
LOW UP THE EAST COAST AND BRINGS A WEAKER TROUGH ACROSS THE AREA. WITH
THIS UNCERTAINTY IN MIND AND THE SLOW PASSAGE OF A FRONTAL
BOUNDARY, FORECAST IS A BLEND OF THE SOLUTIONS, CONTINUING A
CHANCE OF SHOWERS AND THUNDERSTORMS MONDAY NIGHT INTO TUESDAY.
WITH INCREASED CLOUD COVERAGE WITH SHOWERS AND THUNDERSTORMS,
HIGHS ON TUESDAY WILL BE SLIGHTLY COOLER IN COMPARISON TO THE
WEEKEND AND MONDAY, ALTHOUGH STILL AROUND 5 DEGREES ABOVE NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
12Z GFS/00Z ECMWF HAVE DIFFERENT DEPICTIONS IN THE EXTENDED...AND
THEREFORE CONFIDENCE IS BELOW AVERAGE. BOTH MODELS SHOW GENERAL
AGREEMENT THAT THERE WILL BE A NEARLY STATIONARY UPPER LEVEL
LOW/TROUGH NEAR THE CAROLINAS. HOWEVER...MULTIPLE RUNS OF THE GFS
KEEPS THIS FEATURE OVER THE ATLANTIC OCEAN WITH JUST SOME CLOUDS
LOCALLY...WHILE THE ECMWF HAS THE FEATURE INLAND ALONG THE EAST
COAST AND SPREADS RAIN AS FAR WEST AS WEST VIRGINIA AND EASTERN
OHIO. WITH NAEFS AND ECMWF ENSEMBLE KEEPING THE PATTERN A LITTLE
DRIER...HAVE ALSO STUCK WITH A DRIER FORECAST. IF THIS HOLDS...AND
THE GFS FORECAST VERIFIES...THIS PERIOD WILL BE QUITE WARM. GFS
BIAS-CORRECTED GRIDS AND NAEFS METEOGRAMS SUGGEST THAT 90 DEGREES IS
NOT OUT OF THE QUESTION FOR THE START OF THE MEMORIAL DAY WEEKEND.
&&
.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL KEEP SKIES MOSTLY CLEAR AND WINDS BELOW 10 KTS
FOR NEXT 24 HOURS. THE ONLY CLOUDS THAT ARE EXPECTED WILL BE WITH
BLOWOFF FROM POSSIBLE TROPICAL SYSTEM OFF CAROLINAS.
.OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY...
SUNDAY NIGHT SHOULD REMAIN DRY BEFORE COLD FRONT APPROACHES FROM THE
WEST ON MONDAY. CONVECTION WILL ALSO INCREASE FROM THE EAST. SLOW
MOVING FRONT WILL BRING A CONTINUED CHANCE FOR SHOWERS AND
THUNDERSTORMS THROUGH WEDNESDAY. PRECIPITATION SHOULD THEN SHIFT
EAST OF THE AREA BY WEDNESDAY NIGHT.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
342 PM EDT SAT MAY 19 2012
.SYNOPSIS...
HIGH PRESSURE WILL ALLOW FOR DRY AND UNSEASONABLY WARM WEATHER TO
CONTINUE INTO EARLY MONDAY. THE CHANCE OF SHOWERS AND THUNDERSTORMS
WILL RETURN AS A LOW PULLS MOISTURE INTO THE AREA FROM THE SOUTHEAST
AND A FRONTAL BOUNDARY APPROACHES FROM THE WEST.
&&
.NEAR TERM /THROUGH SUNDAY/...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A 500MB RIDGE
EXTENDING FROM THE THE OHIO VALLEY INTO NEW ENGLAND WITH ITS
ASSOCIATED WEAK ANTI-CYCLONIC FLOW CENTERED ACROSS THE OHIO
VALLEY. MEANWHILE, A CLOSED LOW IS LOCATED OFF THE CAROLINA COAST.
AT THE SURFACE, A BROAD AREA OF HIGH PRESSURE IS CENTERED ACROSS
THE NORTHEAST, EXTENDING SOUTHWESTWARD INTO THE REGION.
THE RIDGE WILL SHIFT FURTHER NORTHEAST TONIGHT AND TOMORROW,
ALLOWING FOR DRY WEATHER TO CONTINUE WITH UNSEASONABLY WARM
HIGH TEMPS. SKIES WILL BE MOSTLY CLEAR THROUGH THIS
PERIOD, ASIDE FROM SOME HIGH CIRRUS SPILLING INTO THE AREA AHEAD
OF THE LOW TO THE SOUTHEAST. DESPITE TEMPS IN THE LOW TO MID 80S
FOR HIGHS, DRY AIR IN PLACE ALONG WITH NEAR CALM WINDS AND MOSTLY
CLEAR SKIES OVERNIGHT WILL ALLOW FOR ANOTHER NIGHT OF DECENT
RADIATIONAL COOLING. THUS, LOWS ARE A MAV/MET BLEND, DROPPING TO
NEAR NORMAL SEASONAL VALUES, IN THE LOW TO MID 50S ACROSS THE
AREA. THE GFS INDICATES 850 TEMPS AROUND 15C TOMORROW. THIS WILL
CONTRIBUTE TO YET ANOTHER DAY WITH HIGHS 10-15 DEGREES ABOVE
NORMAL, RANGING FROM THE MID 80S ACROSS THE LOWLANDS TO THE MID
70S ACROSS THE EASTERN RIDGES.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
GFS/ECMWF INDICATE THE RIDGE AXIS BECOMING PINCHED OFF SUNDAY NIGHT
INTO MONDAY AS THE UPPER LOW MOVES INTO VIRGINIA AND A TROUGH MOVES
INTO THE UPPER MIDWEST. THE CLOSED LOW WILL SERVE TO DRAW MOISTURE
INTO THE AREA FROM THE ATLANTIC. WITH THIS IN MIND, THE CHANCE OF
SHOWERS BEGINS SOUTHEAST OF PITTSBURGH ON MONDAY MORNING. IN
ASSOCIATION WITH THE TROUGH, A FRONTAL BOUNDARY WILL CROSS THE OHIO
VALLEY ON MONDAY AFTERNOON. INCREASING MOISTURE AND INSTABILITY
AHEAD OF THIS FEATURE WILL LEAD TO THE CHANCE OF SHOWERS AND
THUNDERSTORMS MONDAY AFTERNOON THROUGH THE EVENING. INCREASED
CLOUD COVERAGE AND COOLER TEMPS ALOFT ASSOCIATED WITH THE LOW
APPROACHING FROM THE SOUTHEAST WILL ALLOW FOR A SLIGHT COOLER DAY
ON MONDAY, WITH HIGH TEMPS AT 5 TO 10 DEGREES ABOVE NORMAL,
RANGING FROM THE LOWER 80S ACROSS EASTERN OHIO TO NEAR 70 ACROSS
THE EASTERN RIDGES.
SOME MODEL UNCERTAINTY ENTERS THE FORECAST IN REGARDS TO THE TROUGH
MOVING INTO THE AREA FROM THE UPPER MIDWEST. ECMWF/NAM SOLUTIONS
MERGE THE UPPER LOW TO THE SOUTHEAST WITH THIS FEATURE INTO A MORE
AMPLIFIED TROUGH ACROSS THE AREA. MEANWHILE, THE GFS MOVES THE UPPER
LOW UP THE EAST COAST AND BRINGS A WEAKER TROUGH ACROSS THE AREA. WITH
THIS UNCERTAINTY IN MIND AND THE SLOW PASSAGE OF A FRONTAL
BOUNDARY, FORECAST IS A BLEND OF THE SOLUTIONS, CONTINUING A
CHANCE OF SHOWERS AND THUNDERSTORMS MONDAY NIGHT INTO TUESDAY.
WITH INCREASED CLOUD COVERAGE WITH SHOWERS AND THUNDERSTORMS,
HIGHS ON TUESDAY WILL BE SLIGHTLY COOLER IN COMPARISON TO THE
WEEKEND AND MONDAY, ALTHOUGH STILL AROUND 5 DEGREES ABOVE NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
12Z GFS/00Z ECMWF HAVE DIFFERENT DEPICTIONS IN THE EXTENDED...AND
THEREFORE CONFIDENCE IS BELOW AVERAGE. BOTH MODELS SHOW GENERAL
AGREEMENT THAT THERE WILL BE A NEARLY STATIONARY UPPER LEVEL
LOW/TROUGH NEAR THE CAROLINAS. HOWEVER...MULTIPLE RUNS OF THE GFS
KEEPS THIS FEATURE OVER THE ATLANTIC OCEAN WITH JUST SOME CLOUDS
LOCALLY...WHILE THE ECMWF HAS THE FEATURE INLAND ALONG THE EAST
COAST AND SPREADS RAIN AS FAR WEST AS WEST VIRGINIA AND EASTERN
OHIO. WITH NAEFS AND ECMWF ENSEMBLE KEEPING THE PATTERN A LITTLE
DRIER...HAVE ALSO STUCK WITH A DRIER FORECAST. IF THIS HOLDS...AND
THE GFS FORECAST VERIFIES...THIS PERIOD WILL BE QUITE WARM. GFS
BIAS-CORRECTED GRIDS AND NAEFS METEOGRAMS SUGGEST THAT 90 DEGREES IS
NOT OUT OF THE QUESTION FOR THE START OF THE MEMORIAL DAY WEEKEND.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL KEEP SKIES MOSTLY CLEAR AND WINDS BELOW 10 KTS
FOR NEXT 24 HOURS. THE ONLY CLOUDS THAT ARE EXPECTED WILL BE WITH
BLOWOFF FROM POSSIBLE TROPICAL SYSTEM OFF CAROLINAS.
.OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY...
SUNDAY NIGHT SHOULD REMAIN DRY BEFORE COLD FRONT APPROACHES FROM THE
WEST ON MONDAY. CONVECTION WILL ALSO INCREASE FROM THE EAST. SLOW
MOVING FRONT WILL BRING A CONTINUED CHANCE FOR SHOWERS AND
THUNDERSTORMS THROUGH WEDNESDAY. PRECIPITATION SHOULD THEN SHIFT
EAST OF THE AREA BY WEDNESDAY NIGHT.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
159 PM EDT SAT MAY 19 2012
.SYNOPSIS...
HIGH PRESSURE WILL ALLOW FOR DRY AND UNSEASONABLY WARM WEATHER TO
CONTINUE INTO EARLY MONDAY. THE CHANCE OF SHOWERS AND THUNDERSTORMS
WILL RETURN AS A LOW PULLS MOISTURE INTO THE AREA FROM THE SOUTHEAST
AND A FRONTAL BOUNDARY APPROACHES FROM THE WEST.
&&
.NEAR TERM /THROUGH SUNDAY/...
18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED WITH MINOR
CHANGES TO THE GOING FORECAST TO ADJUST SKY GRIDS AS THIN CIRRUS
CONTINUES TO FILTER INTO THE AREA WELL AHEAD OF A LOW CENTER OFF THE
CAROLINA COAST.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A 500MB RIDGE
EXTENDING FROM THE THE OHIO VALLEY INTO NEW ENGLAND WITH ITS
ASSOCIATED WEAK ANTI-CYCLONIC FLOW CENTERED ACROSS THE OHIO
VALLEY. MEANWHILE, A CLOSED LOW IS LOCATED OFF THE CAROLINA COAST.
AT THE SURFACE, A BROAD AREA OF HIGH PRESSURE IS CENTERED ACROSS
THE NORTHEAST, EXTENDING SOUTHWESTWARD INTO THE REGION.
THE RIDGE WILL SHIFT FURTHER NORTHEAST TONIGHT AND TOMORROW,
ALLOWING FOR DRY AND UNSEASONABLY WARM WEATHER TO CONTINUE. SKIES
WILL BE MOSTLY CLEAR THROUGH THIS PERIOD, ASIDE FROM SOME HIGH
CIRRUS SPILLING INTO THE AREA AHEAD OF THE LOW TO THE SOUTHEAST.
DESPITE TEMPS IN THE LOW TO MID 80S FOR HIGHS, DRY AIR IN PLACE
ALONG WITH NEAR CALM WINDS AND MOSTLY CLEAR SKIES OVERNIGHT WILL
ALLOW FOR ANOTHER NIGHT OF DECENT RADIATIONAL COOLING. THUS, LOWS
ARE A MAV/MET BLEND, DROPPING TO NEAR NORMAL SEASONAL VALUES, IN THE
LOW TO MID 50S ACROSS THE AREA. THE GFS INDICATES 850 TEMPS AROUND
15C TOMORROW. THIS WILL CONTRIBUTE TO YET ANOTHER DAY WITH HIGHS 10-15
DEGREES ABOVE NORMAL, RANGING FROM THE MID 80S ACROSS THE LOWLANDS
TO THE MID 70S ACROSS THE EASTERN RIDGES.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
MODELS CONTINUE TO STRUGGLE WITH THE INTERACTION OF THE CUTOFF LOW
OVER THE SOUTHEAST THROUGH AND THE TROUGH ACROSS THE UPPER
MIDWEST. AT THIS POINT...THE 500HPA RIDGE SHOULD BEGIN TO PINCH
OFF SUNDAY NIGHT AND AS IT TRANSFERS TO THE COAST THE UPSTREAM
TROUGH ACTUALLY HELPS TO BRING THE CUTOFF LOW FURTHER WEST.
THE ECMWF/GFS CONTINUE TO BE FAVORED THROUGH THIS TIME PERIOD AS
THE NAM KEEPS THE LOW SLIGHTLY FARTHER SOUTH. GRADUALLY INCREASE
PRECIP CHANCES FROM BOTH THE EAST AND WEST MONDAY AS WE ARE
SQUEEZED BETWEEN THE COLD FRONT AND THE CUTOFF LOW AND MAINTAIN
THOSE CHANCES THROUGH TUESDAY.
TEMPERATURES SHOULD CONTINUE TO REMAIN 10 DEGREES ABOVE NORMAL
SUNDAY AND 5-10 DEGREES ABOVE NORMAL MONDAY DESPITE INCREASING
CLOUD COVER AND PRECIPITATION CHANCES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
MODELS CONTINUE TO DISAGREE SOMEWHAT WITH REGARD TO TIMING OF THE
FRONT APPROACHING FROM THE WEST AND ON THE EXTENT OF
RETROGRESSION OF EAST COAST LOW EARLY NEXT WEEK.
STAYED CLOSE TO HPC GUIDANCE WHICH STILL LEANS TOWARD FASTER GFS
TIMING WITH THE FRONT AND PUSHES THE MAIN AREA OF PRECIPITATION
EAST OF THE REGION BY WEDNESDAY NIGHT.
A WEAK SURFACE RIDGE SHOULD PROVIDE GENERALLY DRY WEATHER FOR
THURSDAY INTO FRIDAY FOR MUCH OF THE FORECAST AREA. MOIST SOUTHEAST
FLOW FROM THE ATLANTIC DEPICTED BY THE ECMWF COULD MAINTAIN
SCATTERED PRECIPITATION OVER THE RIDGES ON THURSDAY NIGHT AND
FRIDAY.
TEMPERATURES ARE FORECAST TO RANGE FROM 5 TO 10 DEGREES ABOVE NORMAL
THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
VFR CONDITIONS AND LIGHT EAST WINDS WILL PREVAIL THROUGH THE TAF
PERIOD AS A SURFACE RIDGE HOLDS ALONG THE APPALACHIANS.
.OUTLOOK...SUNDAY THROUGH WEDNESDAY...
THE SURFACE RIDGE WILL MAINTAIN VFR WEATHER THROUGH SUNDAY NIGHT.
A FRONT WILL APPROACH FROM THE WEST LATE MONDAY WHILE A LOW
PRESSURE SYSTEM MOVES INLAND FROM THE CAROLINA COAST. MOISTURE
WILL INCREASE ACROSS THE REGION BY EARLY MONDAY ALONG WITH THE
POTENTIAL FOR RESTRICTIONS IN SHOWERS AND THUNDERSTORMS. SCATTERED
PRECIPITATION SHOULD PERSIST THROUGH WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
133 PM EDT SAT MAY 19 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 508 AM EDT SAT MAY 19 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG OVER THE
GREAT LAKES DOWNSTREAM OF TROF IN THE ROCKIES. CWA IS IN THE WARM
SECTOR E OF SFC-H85 TROF/COLD FNT AND S OF WARM FNT OVER NRN LK SUP/
ADJOINING ONTARIO. WITH DRYNESS SHOWN ON LOCAL 00Z RAOBS /H925 DEWPT
DEPRESSIONS ARE 15 TO 25C ON THE MPX/GRB RAOBS AND THE H85 DEWPT
DEPRESSION AT GRB WAS 49C/...SKIES ARE MOCLR OVER UPR MI. DESPITE
THE CLEAR SKIES/DRY AIR AND LOCAL DECOUPLING... TEMPS ARE WELL ABV
NORMAL WITH STEADY SW FLOW AT H925 LIMITING THE OVERALL DIURNAL TEMP
DROP. SOME SHRA/TS DID IMPACT MUCH OF MN THIS PAST EVNG DESPITE
FAIRLY DRY AIR.AS SHRTWV LIFTED NNEWD WELL E OF THE MAIN TROF TO THE
W...BUT THESE ARE TENDING TO WEAKEN AND STAY W OF EVEN LK SUP. MORE
WIDESPREAD SHRA/TS ARE LOCATED IN THE PLAINS CLOSER TO H85 COLD FNT.
MAIN FCST CONCERNS TDAY ARE FOCUSED ON FIRE WX. FOCUS FOR TNGT THRU
SUN SHIFTS TO SHRA/TS CHCS ASSOCIATED WITH SLOWLY APRCHG UPR TROF/
COLD FNT.
TDAY...CWA WL REMAIN UNDER WARM SW FLOW AS COLD FNT TO THE W SLIDES
EWD THRU MN. ALTHOUGH H85 TEMPS ARE FCST TO AVG ABOUT A DEGREE LOWER
THAN YDAY...VERY DEEP MIXING SHOWN ON THE 00Z MPX RAOB SHOULD
SUPPORT MAX TEMPS NEARLY SIMILAR TO WHAT OCCURRED ON FRI PER
UPSTREAM OBSVD SFC HI TEMPS...WITH SOME PLACES OVER THE W HALF
SEEING THE MERCURY REACH 90. GOING FCST SHOWING THESE HIER TEMPS IN
THE DOWNSLOPE AREAS FM ONTONAGON TO BARAGA LOOK ON TRACK. AREAS OVER
THE E HALF SHOULD SEE SOME MODERATION OFF LK MI. SOME LK MODERATION
MAY SLIP A BIT FARTHER W INTO THE CNTRL IF FCST BACKING WINDS TO
MORE DUE S DRAGS THE LK MI MODERATION INTO THAT AREA. SEE FIRE WX
SECTION BLO FOR A DISCUSSION OF FIRE WX CONCERNS.
TNGT...WITH BLDG UPR RDG FCST OVER THE ERN GRT LKS...OPTED TO FOLLOW
THE SOMEWHAT SLOWER 12Z ECMWF/00Z CNDN MODELS FOR THE TIMING OF THE
COLD FNT...ESPECIALLY SINCE A SHRTWV LIFTING NEWD OUT OF THE ROCKIES
WL INDUCE A LOW PRES TO DVLP ON THIS BNDRY OVER THE PLAINS TDAY.
THIS LO IS FCST TO MOVE INTO MN BY 12Z SUN. THE 00Z NAM HAS TRENDED
IN THIS DIRECTION AS WELL. IN FACT...THE 12Z ECMWF/0Z CNDN MODELS
INDICATE THE BULK OF ANY PCPN WL BE ON THE COLD SIDE OF THE FNT
AND STAY W OF IWD THRU 12Z. THIS FCST IS REASONABLE CONSIDERING THE
DRYNESS OF THE WARM SECTOR AIRMASS AND FCST DEEP LYR QVECTOR CNVGC
BEING FOCUSED UNDER THE SHARPER DPVA ASSOCIATED WITH THE SHRTWV ON
THE COLD SIDE OF THE FNT IN MN EVEN AS LATE AS 12Z SUN. STEADY SW
FLOW IN THE WARM SECTOR SHOULD ONCE AGAIN LIMIT THE DIURNAL FALL OF
TEMP...SO MINS WL BE WELL ABV NORMAL AGAIN.
SUN...SINCE THE FAVORED 12Z ECMWF/00Z CNDN MODELS SHOW BULK OF DEEP
LYR QVECTOR CNVGC SHIFTING NEWD THRU WRN LK SUP TOWARD ONTARIO...
SUSPECT THE HIER POPS WL BE OVER THE NW CWA...WITH PCPN TENDING TO
DIMINISH AS THE FNT SHIFTS TO THE E INTO THE CENTRAL CWA BY LATE
AFTN. HOWEVER...DAYTIME HEATING MAY OFFSET THE LOSS OF BEST
DYNAMICS...ESPECIALLY SINCE THE CNDN MODEL SHOWS HIER H85 DWPTS UP
TO 12C SURGING NEWD RIGHT ALONG THE FNT. HOWEVER...THIS SOMEWHAT
HIER MSTR IS STILL RELATIVELY LO COMPARED TO H85 TEMPS FCST ARND
16C. SO THE LLVLS WL STILL BE RATHER DRY PER THE MODEL FCST
SDNGS...LIMITING DESTABILIZATION. OPTED TO GO WITH LIKELY POPS OVER
THE NW CWA...DIMINISHING TO CHC FARTHER TO THE E. RAISED FCST HI
TEMPS WELL INTO THE 80S OVER THE E AND CNTRL AWAY FM LK MI
MODERATION TO ACCOUNT FOR SLOWER ARRIVAL OF COLD FNT.
SUN NGT...EXPECT COLD FNT TO PUSH THRU THE REST OF THE CWA
ACCOMPANIED BY CHC POPS AS MAIN SHRTWV/SHARPEST DEEP LYR QVECTOR
CNVGC EXITS TO THE NE AND ANY HELP FM DIURNAL HEATING WANES. SINCE
GUIDANCE HINTS AT THE ARPCH OF A SECOND SHRTWV FM MN...MAINTAINED
THE CHC POPS HANGING WELL BACK BEHIND THE COLD FNT AS HINTED AT BY
00Z NAM/12Z ECWMF AND SHOWN IN PREVIOUS FCST DESPITE MID LVL DRYING
IN THE WAKE OF THE INITIAL DISTURBANCE. IF THIS TRAILING SHRTWV IS
WEAKER...THE DRYING BEHIND THE FIRST STRONGER SHRTWV MAY END THE
POPS FASTER THAN FCST AS FCST BY THE 00Z CNDN. THE ARRIVAL OF H85
TEMPS AOB 5C OVER THE W BY 12Z MON WL BRING A RETURN OF MORE
SEASONABLE TEMPS.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 508 AM EDT SAT MAY 19 2012
A SLOWLY TRANSITIONING WX PATTERN...WITH MUCH OF THE PERIOD
CONTINUING TO BE DOMINATED BY SOUTHERLY WINDS.
INITIALLY WE WILL HAVE THE EXITING COLD FRONT TO OUR EAST...AND HIGH
PRESSURE PUSHING IN FROM THE CENTRAL AND N PLAINS. AS A
RESULT...EXPECT TEMPS TO BE 10 TO 15 DEGREES COOLER THAN SUNDAY.
850MB TEMPS WILL BE 4-5C. WITH THE COOL TEMPS WILL COME DRY
AIR...WITH LOWER DEWPOINTS MONDAY AFTERNOON INTO THE MID 30S OVER
THE W HALF. WOULD NOT BE COMPLETELY SHOCKED TO SEE VALUES CLOSER TO
30F...WHICH WOULD GIVE RH VALUES NEAR 25 PERCENT.
THE SFC HIGH WILL BE DIRECTLY OVERHEAD TUESDAY MORNING...BEFORE
SLIDING E. EXPECT THE RETURN OF S WINDS...AND A LITTLE BETTER
MOISTURE. WE WILL SEE STRONGER SOUTHERLY WINDS RETURN BRIEFLY
WEDNESDAY AFTERNOON. ADJUSTED MAX TEMPS UP OVER THE TRADITIONAL
DOWNSLOPE AREAS NEAR LAKE SUPERIOR...WITH 850MB TEMPS RISING TO 11
TO 15C WITH THE COOLEST VALUES EAST.
WENT ABOVE CONSENSUS FOR HIGH TEMPS THURSDAY...ONCE AGAIN WITH A
MORE SIGNIFICANT INCREASE TO DOWNSLOPE AREAS. 850MB WINDS PEG OUT
BETWEEN 45 AND 60KTS...AND TEMPS JUMP UP TO 15-18C. THE 19/00Z GFS
IS ONE OF THE COOLEST SOLUTIONS.
WILL BE INTERESTING HOW THE END OF THE WORK WEEK PANS OUT...AND IF
THE FRONTAL BOUNDARY SETS UP AND STALLS OVER THE W CWA LIKE THE
19/00Z ECMWF...OR BLOWS THROUGH OUR AREA THURSDAY NIGHT BEFORE
STALLING OVER LOWER MI FRIDAY INTO SATURDAY. WILL NOT GET TOO FANCY
WITH THE FORECAST THAT FAR OUT...AND WILL KEEP THE SLIGHT CHANCE/LOW
CHANCE POPS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 133 PM EDT SAT MAY 19 2012
EXPECT VFR CONDITIONS FOR MOST OF THE FORECAST PERIOD AT THE TAF
SITES. A COLD FRONT APPROACHING THE AREA LATE TONIGHT INTO
TOMORROW WILL BRING INCREASING CLOUD COVER AND A CHANCE OF SHOWERS
AND POSSIBLY A THUNDERSTORM TO KIWD/KCMX. STILL SOME UNCERTAINTY
ON INTENSITY OF THE SHOWERS...SO HAVE LEFT VSBYS AT VFR. ONE FINAL
ITEM OF NOTE IS THE POTENTIAL FOR CIGS TO DROP AT KIWD/KCMX LATE IN
THE PERIOD IF FOG DEVELOPS OVER WRN LK SUPERIOR LATE TONIGHT INTO
TOMORROW MORNING. WINDS TURNING TO THE WNW BEHIND THE FRONT WOULD
PUSH THE FOG ONSHORE AND EFFECT BOTH SITES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EDT SAT MAY 19 2012
WINDS SHOULD REMAIN BELOW 30KTS THROUGH THE PERIOD. LOW PRESSURE
STRETCHING FROM SOUTHWESTERN QUEBEC TO NEBRASKA WILL SHIFT
NORTHEASTWARD...FILLING SLIGHTLY AS IT CROSSES LAKE SUPERIOR SUNDAY
INTO SUNDAY EVENING. BEHIND THIS FEATURE...HIGH PRESSURE WILL BUILD
ACROSS THE UPPER GREAT LAKES MONDAY AND MONDAY NIGHT. EXPECT THE
HIGH TO SLOWLY EXIT NORTHEASTWARD THROUGH MID WEEK...IN RESPONSE TO
A STRONGER LOW NEARING FROM SOUTH CENTRAL CANADA THROUGH THE CENTRAL
PLAINS. EXPECT THE LOW TO OUR WEST TO MOVE OVER ONTARIO ON
THURSDAY...BEFORE EDGING ACROSS LAKE SUPERIOR THURSDAY NIGHT.
&&
.FIRE WEATHER...
ISSUED AT 508 AM EDT SAT MAY 19 2012
AFTER AN OVERNGT OF RELATIVELY POOR RH RECOVERY...EXPECT ANOTHER DAY
OF AT LEAST NEAR CRITICAL FIRE WX PARAMETERS. MAX TEMPS THIS AFTN
WILL BE SIMILAR TO WHAT WAS OBSVD YDAY...BUT DEEPER MIXING SHOWN
ESPECIALLY ON THE 00Z MPX RAOB MIGHT TAP INTO LOWER DEWPTS. IN
FACT...SFC DEWPTS WERE AS LO AS 35 TO 45 UPSTREAM YDAY AFTN IN WRN
WI/SRN MN. BLENDED MIXED DEWPT TOOL VALUES WITH THE PREVIOUS FCST
DEWPTS TO COME UP WITH READINGS DIPPING AS LO AS 43 OR SO. WITH
WINDS ALOFT TDAY ALSO NEARLY SIMILAR TO YDAY AND DEEP MIXING RELATED
TO DAYTIME HEATING... SUSTAINED WINDS AS HI AS 10 TO 20 MPH WITH
GUSTS TO 30 MPH AT THE MORE EXPOSED LOCATIONS ARE LIKELY. OPTED TO
ISSUE RFW FOR AN ARK FROM IWD/ONTONAGON TO BARAGA/MQT
COUNTIES...AREAS THAT SAW THE POOREST RH RECOVERY EARLY THIS MRNG
AND WHERE STRONGER WINDS/HIER DAYTIME HI TEMPS ARE MOST LIKELY. WL
ISSUE RFD FOR THE OTHER COUNTIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
RED FLAG WARNING UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING FOR
MIZ002-004-005-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...SRF
MARINE...KF
FIRE WEATHER...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1255 PM CDT SAT MAY 19 2012
.UPDATE...
UPDATED FOR AVIATION DISCUSSION BELOW.
&&
.DISCUSSION...
/ISSUED 429 AM CDT SAT MAY 19 2012/
WATER VAPOR IMAGERY AND RUC H5 ANALYSIS SHOWS A RATHER EXPANSIVE
RIDGE IN PLACE THIS MORNING EAST OF THE MS RIVER...WITH A RATHER
COMPLEX TROUGH MOVING INTO THE HIGH PLAINS...WITH SEVERAL
SHORTWAVES EMBEDDED WITHIN IT. THE TWO PRIMARY ONES ARE CURRENTLY
OVER ERN SODAK AND MOVING FROM CO UP INTO SRN NEB. AT THE
SFC...A COUPLE OF AREAS OF LOW PRESSURE COULD BE FOUND OVER FAR NW
ONTARIO...WITH ANOTHER NEAR THE CO/NEB/KS BORDER. A COLD FRONT IS
ANALYZED BETWEEN THESE LOWS ACROSS THE ERN DAKOTAS.
FOR THE H5 PATTERN...THE RIDGING NOW MOVING ON TO THE HIGH PLAINS
WILL SLOWLY BEAT DOWN THE ERN RIDGE...WITH THE TROUGH CURRENTLY
COMING OUT OF CO WORKING ACROSS THE MPX CWA SUN INTO SUN EVENING.
FOR MON/TUE...RIDGING WILL BE BUILDING IN ACROSS CENTRAL NOAM AS A
SIGNIFICANT TROUGH DIGS INTO THE PAC NW. AS WE HEAD THROUGH THE
SECOND HALF OF NEXT WEEK...THIS PATTERN LOOKS BECOME QUITE
AMPLIFIED...AS VERY HIGH HEIGHTS SET UP INTO THE GREAT
LAKES...WITH A QUASI-STATIONARY DEEP TROUGH TAKING HOLD ACROSS
THE NRN ROCKIES...SETTING THE UPPER MIDWEST UP INTO A POTENTIAL
ACTIVE PATTERN.
AT THE SFC...THE COLD FRONT WILL WORK INTO WRN MN BY THIS
AFTERNOON...AND CLEAR THE MPX WI COUNTIES SUN AFTERNOON. THE LOW
CENTER CURRENTLY NEAR THE CO/NEB/KS WILL TRACK ACROSS SOUTH
CENTRAL MN INTO THE WRN TIP OF THE U.P. OF MICH SAT NIGHT/SUN.
HIGH PRESSURE WILL THEN SLIDE ACROSS THE AREA MON/TUE...BEFORE LEE
SIDE TROUGHING REESTABLISHES ITSELF OVER THE NRN HIGH PLAINS WED.
NEXT FRONT STILL ON TAP TO MOVE INTO MN WED NIGHT...AND WITH UPPER
RIDGE AMPLIFYING OVER THE GREAT LAKES THE LATTER HALF OF NEXT
WEEK...THIS FRONT STILL LOOKS TO STALL OUT THEN MEANDER AROUND THE
UPPER MS VALLEY INTO THE HOLIDAY WEEKEND.
THIS MORNING...STRONG WAA OUT AHEAD OF THE ERN SODAK SHORTWAVE
HAS RESULTED IN THE DEVELOPMENT OF AN AREA OF TSRA OVER WRN
MN...RADAR TRENDS MATCH WELL WITH THE IDEA THE RUC IS
SHOWING...WITH THIS WAA AND ASSOCIATED ACTIVITY BASICALLY GOING
DUE NORTH INTO NW MN. DO EXPECT CONDITIONS TO BE FAIRLY QUIET
THROUGH THE MORNING...WITH THE SODAK SHORTWAVE AND COLD FRONT
EXPECTED TO REMAIN WEST OF THE AREA. ONE CAVEAT IS THE LLJ AND
STRONG MOISTURE TRANSPORT IN PLACE ACROSS THE WEST. THIS MAY KEEP
SCT SHRA/TSRA ACTIVITY GOING THROUGH THE MORNING OUT WEST...BUT
DID NOT PLAY THIS IDEA UP TO MUCH IN THE GRIDS. INSTEAD...WAITED
UNTIL THE AFTERNOON TO REALLY GET POPS GOING. BY THEN THE COLD
FRONT WILL BE WORKING INTO WRN MN AS UPPER ENERGY BEGINS TO WORK
IN OVERHEAD. LOOKING AT HIRES REFLECTIVITY FORECASTS...SEEMS TO BE
GOOD AGREEMENT WITH STORMS INITIATING NEAR A RWF TO LONG PRAIRIE
LINE BETWEEN 20 AND 22Z...WITH ACTIVITY WORKING EAST TOWARD THE
I-35 CORRIDOR SHORTLY AFTER 00Z. FORECAST SOUNDINGS AGAIN SHOW
NICE INVERTED-V STRUCTURE THIS AFTERNOON...WITH MLCAPE AGAIN
PUSHING UP TO AROUND 1500 J/KG. IN ADDITION...UNLIKE
YESTERDAY...BULK SHEAR WILL BE IN THE 30-40 KT RANGE...INDICATING
SOME BETTER ORGANIZATION IN CONVECTION IS POSSIBLE. GIVEN LESS
FAVORABLE CONDITIONS MANAGED A FEW 60-70 MPH WIND GUSTS AND GOLF
BALL SIZE HAIL FRIDAY...DO NOT SEE WHY WE DO NOT HAVE A SIMILAR
THREAT FOR SEVERE WEATHER TODAY. IF ANYTHING...WOULD SUSPECT THE
WIND THREAT IS A BIT HIGHER AS BETTER SHEAR AND FAVORABLE
CONDITIONS FOR COLD POOL GENERATION MAY SUPPORT THE DEVELOPMENT OF
ORGANIZED LINE SEGMENTS. BESIDE THE PRECIP...SHOULD BE ANOTHER
WARM DAY...THOUGH NOT EXPECTING WIDESPREAD 90S LIKE FRIDAY. TWO
LIMITING FACTORS FOR HIGHS TODAY WILL BE MORE CLOUD COVER AND
ABOUT A 4 DEG C DROP IN H85 TEMPS. WITH THAT SAID...GUIDANCE HAS
HAD A PRETTY STRONG COLD BIAS IN THIS HEAT WAVE...SO CONTINUED TO
RUN WITH HIGHS A BIT HIGHER THAN WHAT MOST GUIDANCE WOULD SUGGEST.
FOR TONIGHT...WITH THE ARRIVAL OF THE UPPER TROUGH AND ATTENDANT
SFC LOW...WE CONTINUE TO SEE A STRONG SIGNAL FOR THE FORMATION OF
A DEFORMATION BAND OF PRECIP JUST TO THE WEST OF THE SFC LOW
TRACK. BLENDED THE ECMWF/GEM/SREF FOR PRECIP TONIGHT...WITH
HEAVIEST BAND OF PRECIP EXPECTED TO SETUP BETWEEN THE WRN TWIN
CITIES METRO AND MARSHALL/ALEXANDRIA. WITH THE SFC LOW COMING
THROUGH...THIS REALLY SLOWS DOWN THE PRECIP...AND CONTINUED TO
LEAN TIMING OF POPS ON SUN CLOSE TO THE ECMWF. THE ECMWF ALONG THE
NAM/SREF WOULD INDICATE SUNDAY BEING CLOUDY/RAINY FOR MOST OF THE
DAY SUNDAY ACROSS MOST OF THE MN MPX AREA...WITH HIGHS LIKELY NOT
LEAVING THE LOWER 60S. FURTHER EAST...THE COLD FRONT/LOW SHOULD BE
NEAR AN EAU/LADYSMITH LINE BY 18Z...SO SEVERE THREAT CERTAINLY
LOOKS BETTER EAST...THOUGH A MARGINAL TREAT FOR SEVERE WEATHER CAN
NOT BE RULED OUT IN THE FAR EAST.
MON THROUGH WED STILL LOOK DRY AS HIGH PRESSURE SLIDES ACROSS THE
AREA. BIGGEST THING TO WATCH WILL BE LOWS MONDAY MORNING. IF HIGHS
ONLY TOP OUT AROUND 60 IN CENTRAL MN...WE COULD SEE LOWS MONDAY
MORNING MAKE A RUN AT THE UPPER 30S AS HIGH PRESSURES MOVES IN AND
SKIES CLEAR OUT. OTHER THAN THAT...ITS OFF TO WAITING FOR THE NEXT
FRONT WEDNESDAY NIGHT. THE ONLY SIGNIFICANT CHANGE NOTED IN THE
MODELS WITH THIS FRONT IS THE 19.00 ECMWF BASICALLY HALTS ITS EWRD
PROGRESSION ACROSS WRN MN...WITH THE RAIN NOT MAKING IT TO ERN
AREAS. AT ANY RATE...CONTINUED TO MENTION HIGH CHANCE/LIKELY
POPS...ESPECIALLY WEST WED NIGHT. AFTER THAT...THE QUESTION
BECOMES WHERE DOES THE FRONT SET UP. WHERE EVER IT DOES SETUP...NORTH
OF THE BOUNDARY THROUGH THE WEEKEND IS LOOKING LIKE IT COULD BE A
BREEDING GROUND FOR SOME ACTIVE WEATHER...CERTAINLY SOMETHING TO
KEEP A CLOSE EYE ON AS WE HEAD INTO THE BUSY HOLIDAY WEEKEND.
&&
.AVIATION.../18Z TAF ISSUANCE/
THE MAIN AVIATION CONCERNS REMAIN...TIMING OF THUNDER THIS
AFTERNOON/TONIGHT AND DEVELOPMENT OF MVFR/IFR CEILINGS. COLD FRONT
PUSHING INTO WEST CENTRAL MINNESOTA AT THIS TIME...MOVED THROUGH
KAXN AS OF 18Z. THIS SHOULD DISSIPATE ANY SIGNIFICANT THREAT OF
THUNDER THERE THIS AFTERNOON. STILL INCLUDED TEMPO FOR A FEW HOURS
LATE THE AFTERNOON...AS IT REMAINS CLOSE TO FRONT. REMAINDER OF
AREA REMAINS TIMING ISSUE. INITIAL SHORT WAVE APPEARS TO BE MOVING
THROUGH EAST CENTRAL MN AT THIS TIME. SHOWERS DISSIPATED PER MODEL
TRENDS. STILL SOME THREAT OF REDEVELOPMENT EAST CENTRAL INTO
WISCONSIN THIS AFTERNOON...WHERE HIGH INSTABILITY REMAINS. BETTER
LIFT LOOKS TO ARRIVE LATER THIS AFTERNOON INTO THE EVENING WITH
TEMPO THUNDER CONTINUED AHEAD OF THE FRONT TONIGHT. EXPECT MVFR
CEILINGS INTO KAXN THIS AFTERNOON...AND THEN LOWERING TOWARD
KSTC-KRWF TONIGHT WITH POST-FRONTAL RAIN. BEST CHANCE FOR IFR WILL
BE THE KRWF TO KSTC AREA. THIS ALL SPREADS EAST OVERNIGHT/SUNDAY
MORNING AND SHOULD END IN EASTERN MN THROUGH 14Z AND BEFORE 19Z IN
WEST CENTRAL WISCONSIN.
KMSP...WEAK WAVE MOVING ACROSS AREA EARLY...MAY INITIATE
SHOWERS/STORMS INTO WESTERN WISCONSIN. OTHERWISE...WILL HAVE TO WAIT
FOR COLD FRONT AS IT MOVES INTO THE AREA THIS EVENING. SHOULD MOVE
THROUGH BY 06Z WITH THUNDER THREAT ENDING THEN. LINGERING SHRA AND
MVFR CEILINGS BEHIND FRONT THROUGH ABOUT 12Z...BECOMING VFR AGAIN
AFTER 15Z SUNDAY.
OUTLOOK...
SUN...SHRA AND SOME TSRA POSSIBLE IN THE MORNING FAR EASTERN MN AND
WESTERN WI WITH MVFR/IFR POSSIBLE THEN IMPROVING CONDITIONS BY
SUNDAY AFTERNOON ALL BUT WESTERN WISCONSIN.
SUN NIGHT MON-TUE...VFR.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/TDK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
345 PM CDT SAT MAY 19 2012
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
353 PM CDT SAT MAY 19 2012
AT 3 PM...A COLD FRONT EXTENDED FROM INTERNATIONAL FALLS MINNESOTA
TO SIOUX CITY IOWA. TEMPERATURES AHEAD OF THIS FRONT WERE IN THE
80S AND 90S. LA CROSSE WISCONSIN HAS REACHED 91 DEGREES. THIS WAS
THEIR FIRST 90-DEGREE TEMPERATURE OF 2012. BEHIND THIS FRONT...
TEMPERATURES WERE IN THE 50S AND 60S. WATER VAPOR AND PROFILERS
INDICATE A WEAK SHORT WAVE TROUGH MOVING THROUGH EASTERN MINNESOTA
AND WESTERN MINNESOTA. THIS SYSTEM IS PRODUCING SOME MID AND HIGH
CLOUDS. IN ADDITION...A FEW ISOLATED SHOWERS NEAR RED WING.
THE 19.18Z RAP AND 19.15Z HRRR CONTINUE TO SUGGEST THAT SCATTERED
SHOWERS AND THUNDERSTORMS WILL REMAIN MAINLY NORTHWEST OF A
PRESTON MINNESOTA TO NEILLSVILLE WISCONSIN LINE THIS EVENING.
WHILE THE 0-6KM SHEAR IS INCREASING TO GREATER THAN 40 KNOTS BY
20.06Z...THE ML SHEAR IS RAPIDLY DECREASING. AS A RESULT...THE
SEVERE WEATHER THREAT LOOKS VERY LOW. IF SOMETHING DID HAPPEN TO
OCCUR...DAMAGING WINDS WOULD BE THE MAIN THREAT. THIS IS MAINLY A
RESULT OF THE DRY AIR LOCATED BELOW THE CLOUD LAYER.
FROM LATE TONIGHT THROUGH EARLY SUNDAY AFTERNOON...THE COLD FRONT
WILL QUICKLY TRANSITION EASTWARD ACROSS THE FORECAST AREA. THIS IS
VERY SIMILAR TO SPEED THAT WAS SHOWN IN THE 18.12Z GFS. WITH THIS
TIMING...IT WILL BE MOVING THROUGH THE REGION DURING A TIME WHEN
THE ML CAPES WILL BE AT THEIR MINIMUM /GENERALLY LESS THAN 1000 J/KG/.
AS THE POSITIVELY TILTED TROUGH MOVES AWAY FROM THE AREA DURING
THE MORNING...THE BEST MOISTURE TRANSPORT AND 0-6 KM SHEAR WILL
MOVE NORTH AWAY FROM THE REGION. DUE TO THIS...THE AREAL COVERAGE
LOOKS TO BE SCATTERED AT BEST AND THE SEVERE WEATHER THREAT LOOKS
VERY SMALL. WITH A FASTER MOTION...THE AFTERNOON PRECIPITATION
CHANCES WERE LOWERED ACROSS THE AREA. IN ADDITION...A CLEARING
TREND IN THE CLOUDS WAS INTRODUCED. THIS LOOKS TO BE FAST ENOUGH
THAT MOST AREAS WILL GET AN OPPORTUNITY TO SEE THE ANNULAR ECLIPSE
ON SUNDAY EVENING. TEMPERATURES ACROSS NORTHEAST IOWA AND
SOUTHEAST MINNESOTA WILL LIKELY REMAIN STEADY THROUGHOUT THE DAY...
AND FALL DURING THE LATE MORNING AND AFTERNOON ACROSS WESTERN
WISCONSIN. THIS NON-DIURNAL TREND WAS INTRODUCED BY THE MIDNIGHT
CREW AND KEPT IN THE HOURLY TEMPERATURE GRIDS.
ON MONDAY...THE 850 MB TEMPERATURES LOOKS TO BE ABOUT 2C WARMER
THAN THE PREVIOUS MODELS. AS A RESULT...THE MAXIMUM TEMPERATURES
WERE RAISED ANYWHERE FROM 3 TO 5F.
.LONG TERM...TUESDAY THROUGH SATURDAY
353 PM CDT SAT MAY 19 2012
NEGATIVE OUTGOING LONG WAVE RADIATION ACROSS THE WESTERN
EQUATORIAL PACIFIC CONTINUES TO SHOW A RETROGRESSION TOWARD
INDONESIA. WITH SEA SURFACE TEMPERATURES IN THE EXCESS OF
26C...THIS AREA IS FAVORABLE TO SUPPORT STRONG TROPICAL FORCING.
NORMALLY WHEN THE CONVECTION IS ROBUST IN THIS AREA...A NEGATIVE
PACIFIC NORTH-AMERICAN TELECONNECTION DEVELOPS /WESTERN TROUGH AND
AN AMPLIFICATION OF AN EASTERN RIDGE/ ACROSS THE NORTH AMERICAN
CONTINENT. AT THE SAME TIME...ANOTHER AREA OF NEGATIVE OUTGOING
LONG WAVE RADIATION OVER THE EASTERN PACIFIC AND CENTRAL AMERICA
IS EXPECTED TO MOVE SLOWLY EAST ACROSS THE ATLANTIC. AS THIS
OCCURS...THE PERSISTENT TROUGH FROM THE MID-ATLANTIC SOUTH INTO
THE YUCATAN PENINSULA WILL MOVE EAST INTO THE CARIBBEAN.
OVERALL...THE 19.12Z MODELS SEEM TO HAVE A FAIRLY GOOD HANDLE ON
THIS SITUATION. THEY ARE IN GOOD AGREEMENT THAT A COLD FRONT WILL
MOVE SOUTHWARD INTO THE FORECAST AREA ON WEDNESDAY NIGHT...AND
THEN IT BECOMES STATIONARY FOR THURSDAY AND THURSDAY NIGHT. THIS
FRONT THEN MOVES NORTHWARD AS A WARM FRONT ON FRIDAY AS THE UPPER
LEVEL RIDGE BUILDS. THIS FRONT WILL BE THE FOCUS FOR SCATTERED
SHOWERS AND THUNDERSTORMS. IT WAS THE CONSENSUS THAT THE
OPERATIONAL GFS WAS TOO FAR SOUTH WITH THIS FRONT FROM FRIDAY INTO
SATURDAY NIGHT...THEREFORE...THE FORECAST WAS TRENDED MORE TOWARD
A BLEND OF THE ECMWF...GEM...AND A MAJORITY OF THE GFS SOLUTIONS.
BY DOING THIS...THE PRECIPITATION CHANCES WERE REMOVED SOUTH OF
THE INTERSTATE 90 CORRIDOR ON FRIDAY...AND ACROSS THE ENTIRE AREA
FROM FRIDAY NIGHT INTO SATURDAY NIGHT. IN ADDITION...THE
TEMPERATURES WERE RAISED FOR THIS TIME PERIOD. IF THE 19.12Z ECMWF
IS CORRECT ON SATURDAY...TEMPERATURES COULD BE WELL INTO THE MID
AND UPPER 90S.
&&
.AVIATION...THIS AFTERNOON THROUGH SUNDAY
1230 PM CDT SAT MAY 19 2012
THE GENERALLY DRY LOWER LEVELS AND BREEZY SOUTH FLOW WILL KEEP
CONDITIONS VFR AT BOTH KLSE AND KRST INTO THIS EVENING. WINDS WILL
AGAIN BE 10-20KTS G20-30KTS THIS AFTERNOON...STRONGEST AT THE HIGHER
TERRAIN/OPEN COUNTRY LOCATIONS...DIMINISHING QUICKLY THIS EVENING.
MOISTURE WILL CONTINUE TO INCREASE TONIGHT...AHEAD OF A COLD FRONT
DUE TO MOVE ACROSS THE AREA VERY LATE TONIGHT/MON MORNING. FRONT
LOOKS TO MOVE ACROSS KRST AROUND 12Z AND KLSE AROUND 15Z...WITH
WINDS SHIFTING TO THE NORTHWEST BEHIND IT. FRONT WILL ACT AS A FOCUS
FOR SHRA/TSRA DEVELOPMENT AS IT MOVES ACROSS THE AREA LATE TONIGHT/
SUN MORNING. FORCING IS ON THE WEAK SIDE AND WITH CONVECTION
EXPECTED TO BE SCT AS THE FRONT MOVES THRU...LEFT CIGS/VSBYS LATE
TONIGHT/SUN MORNING VFR. MAY YET NEED A TEMPO OR PREVAILING PERIOD
OF MVFR CIG/VSBY IN THE 09Z-15Z TIME-FRAME ONCE A MORE PRECISE
TIMING OF THE FRONT CAN BE DETERMINED...OR IF IT APPEARS A BKN LINE
OF CONVECTION WITH SOME STRONGER CELLS/TSRA WILL MOVE ACROSS THE TAF
SITES. GIVE LOWER PROBABILITY OF THIS AT THIS TIME...LEFT MVFR
MENTION CENTERED ON 12Z SUN OUT OF TAFS FOR NOW. DRIER NORTHWEST
FLOW/HIGH PRESSURE WILL BUILD ACROSS THE AREA BEHIND THE FRONT...
WITH GOOD VFR CONDITIONS EXPECTED BY LATE SUN MORNING/SUN AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
253 PM CDT SAT MAY 19 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
218 PM CDT SAT MAY 19 2012
.SHORT TERM...TONIGHT AND SUNDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COLD FRONT
MOVING ACROSS THE NORTHERN MISSISSIPPI VALLEY AND HIGH PRESSURE
CENTERED OVER THE APPALACHIANS. THE FRONT HAS BEEN MOSTLY INACTIVE
SO FAR TODAY...THOUGH CONVECTION IS EXPECTED TO DEVELOP LATER THIS
AFTERNOON OVER MINNESOTA. EARLIER SHOWERS AND STORMS ALONG A
305-310K MOISTURE GRADIENT HAVE FIZZLED...AND THE LEFT OVER CIRRUS
SHIELD IS NOW ADVANCING INTO SW WISCONSIN. MOISTURE HAS BEEN
INCREASING TODAY ACROSS THE AREA AS EVIDENT BY RISING SURFACE
DEWPOINTS AND CU FORMATION. AS A SHORTWAVE OVER THE PLAINS PUSHES
THE FRONT TO THE EAST OVER THE NEXT 24 HOURS...PRECIP AND SEVERE
WEATHER CHANCES ARE THE MAIN FORECAST CONCERNS.
TONIGHT...THE COLD FRONT EXTENDING FROM THE NORTHERN MISSISSIPPI
VALLEY TO THE TEXAS PANHANDLE WILL SLOWLY MOVE EAST TONIGHT ACROSS
EASTERN MINNESOTA AND NW WISCONSIN. BEHIND THE FRONT...RIGHT REAR
QUAD OF THE JET...DPVA FROM THE SHORTWAVE...AND MID-LEVEL FGEN WILL
PROVIDE A CHANCE OF PRECIP. HAVE CONFINED POPS OVERNIGHT TO CENTRAL
AND NORTH-CENTRAL WISCONSIN IN CASE UPSTREAM PRECIP SNEAKS FARTHER
EAST.
NOT QUITE AS CONFIDENT ABOUT THIS EVENING HOWEVER. BAND OF PRECIP
THAT STRETCHED FROM SOUTHERN MINNESOTA TO MISSOURI DISSIPATED BY
MIDDAY...POSSIBLY AS A RESULT OF DIMINISHING MID-LEVEL CONVERGENCE.
MOISTURE ADVECTION ON THE 305-310K ISENTROPIC SURFACES...WHICH WAS
ALIGNED WITH THE BAND OF PRECIP...WILL MOVE ACROSS THE FORECAST AREA
THIS EVENING...UNDER MID-LEVEL LAPSE RATES OF 7.5-8 C/KM. PROGGED
SOUNDINGS INDICATE ELEVATED CAPES BETWEEN 500-1000 J/KG ARRIVE WITH
THE MOISTURE ADVECTION. DO NOT SEE THE MID-LEVEL CONVERGENCE
RETURNING...BUT DO NOT NECESSARILY TRUST GOING DRY EITHER. SINCE THE
CLOUD BAND HAS BEEN THINNING AND CLOUD TOPS WARMING...HAVE DECIDED
TO GO DRY THIS EVENING.
SUNDAY...THE SHORTWAVE TROUGH WILL MOVE ACROSS CENTRAL AND
NORTH-CENTRAL WISCONSIN DURING THE MORNING...AND NORTHEAST WISCONSIN
IN THE AFTERNOON. WITH FORCING BEHIND THE FRONT HOLDING
TOGETHER...SHOULD SEE SCT SHOWERS AND THUNDERSTORMS MOVE EAST ACROSS
THE FORECAST AREA THROUGH THE DAY. AN UPTICK OF SHOWERS AND STORMS
WILL BE POSSIBLE IN THE AFTERNOON OVER NORTHEAST WISCONSIN WHERE
THERE WILL BE HIGHER DAYTIME INSTABILITY. ASSUMING CLOUD COVER
ALLOWS SUFFICIENT SUNSHINE...BOTH THE NAM AND GFS INDICATE 1000-1500
J/KG OF ML CAPE DEVELOPING BY MIDDAY...USING A SURFACE PARCEL OF
80F/61F. HIGHER WINDS ALOFT WILL EXIST BEHIND THE FRONT...BUT 0-6KM
BULK SHEAR VALUES OF 25-30KT...WEAK CONVERGENCE ALONG THE
FRONT...AND A FAIRLY UNIDIRECTIONAL WIND PROFILE SUGGESTS AN
ISOLATED THREAT FOR SEVERE STORMS FOR WINDS AND HAIL AHEAD OF THE
FRONT OVER NE WISCONSIN IN THE AFTERNOON. WILL KEEP A MENTION IN
THE HWO. MORNING PRECIP WILL HOLD BACK TEMPS OVER CENTRAL AND
NORTH-CENTRAL WISCONSIN IN THE MID 70S...WHILE NORTHEAST WISCONSIN
COULD POSSIBLY REACH INTO THE LOWER TO MID 80S.
.LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY. TIMING OF PCPN
CHANCES WILL BE THE PRIMARY CHALLENGE.
MAIN CHANGE FOR SUNDAY EVENING IS THE FASTER FROPA AND BEST
INSTABILITY IS DIMINISHING QUICKLY. WILL HANG ONTO A LINGERING
CHANCE OF LIGHT CONVECTION FOR EASTERN WISCONSIN AS A MID LEVEL
TROUGH WILL TRAIL THE SURFACE COLD FRONT SLIGHTLY.
OTHERWISE HIGH PRESSURE WILL DOMINATE THE WEATHER PATTERN LATER
SUNDAY NIGHT INTO WEDNESDAY. UPPER RIDGE BUILDS INTO THE NORTHERN
PLAINS BY THE MIDDLE OF THE NEXT WEEK. MEDIUM RANGE RUNS DIVERT ON
LOCATION OF RETURN FLOW AHEAD OF A LOW PRESSURE SYSTEM OVER THE
NORTHERN PLAINS. THE GFS ATTEMPTS TO DEVELOP SMALL CHC POPS OVER
NORTH CENTRAL WISCONSIN CLOSER TO THE RETURN FLOW. MEDIUM RANGE
MODEL RUNS DIVERT AFTER THURSDAY AND THEREFORE RESOLUTION OF THE
FORECAST DIMINISHES. THE GFS BREAKS DOWN THE UPPER RIDGE FASTER
FOR LATER NEXT WEEK AND DRAGS THE FRONTAL SYSTEM OVER FASTER VS
THE SLOWER ECMWF. THE ECMWF ALSO BUILDS THE RIDGE AGAIN FOR A
WARMER NEXT WEEKEND. BLEND OF THE RUNS PRODUCING WIDESPREAD
SLIGHT CHANCES IN THE FORECAST DUE TO THIS TIMING ISSUE. THIS
TIMING OF THE BREAKDOWN OF THE WARM RIDGE ALSO IMPACT THE
TEMPERATURE MAX/MIN`S.
&&
.AVIATION...VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH AT LEAST
TONIGHT. THERE IS A VERY SMALL CHANCE OF A SHOWER THIS
EVENING...BUT SCT PRECIP OVER THE PLAINS IS DIMINISHING AS IT MOVES
NORTHEAST. SO NOT WORTH INCLUDING IN THE TAFS AT THIS TIME. GUSTY
SOUTH-SOUTHWEST WINDS WILL CONTINUE THROUGH EARLY THIS EVENING
BEFORE DIMINISHING. LLWS TO DEVELOP OVER CENTRAL AND NORTH-CENTRAL
WISCONSIN TONIGHT AS A COLD FRONT MOVES INTO THE STATE. THIS FRONT
WILL HAVE POTENTIAL TO CREATE SHOWERS AND THUNDERSTORMS THROUGH THE
DAY ON SUNDAY.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/TDH