Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/20/12
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1129 AM MDT FRI MAY 18 2012
.UPDATE...
ISSUED AT 1117 AM MDT FRI MAY 18 2012
CONVECTION QUICKLY FIRING THIS MORNING ACROSS NORTHEAST UTAH AND
ACTIVITY IS DEVELOPING IN STRONGLY INVERTED-V ENVIRONMENT BASED ON
MORNING SOUNDINGS. STRONG OUTFLOW WINDS WILL BE OUR BIGGEST
CONCERN FROM THESE STORMS AS WE AWAIT THE ARRIVAL OF THE COLD
FRONT AND ITS ASSOCIATED SHORTWAVE TROUGH PUSHING ACROSS UTAH.
LATEST WATER VAPOR IMAGERY SHOWING SOME DRIER AIR MOVING INTO THE
SOUTHERN ZONES...BUT BEST DRY PUNCH WILL REMAIN WELL SOUTH OF THE
FORECAST AREA. CLOUD COVER HAS BEEN SLOW TO ERODE THIS MORNING
AND CU FIELDS QUICKLY POPPING IN CLEAR AREAS...SO BEST HEATING MAY
NOT BE REALIZED TODAY...WHICH WILL HINDER OUR STRONGER CONVECTION
A BIT. IN ANY CASE...THE AFTERNOON AND EVENINGS HOURS WILL BE
RATHER ACTIVE AND FORECASTS HAVE BEEN UPDATED TO ACCOUNT FOR THE
LATEST TRENDS. LOOKS LIKE THE FRONT WILL ARRIVE AFTER 4 PM AND
PASS THROUGH THE ENTIRE FORECAST AREA BY MID EVENING.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 411 AM MDT FRI MAY 18 2012
TODAY...CRITICAL FIRE WEATHER CONDITIONS WILL DEVELOP OVER MUCH OF
THE FORECAST AREA BEGINNING LATE THIS MORNING AND CONTINUING INTO
THIS EVENING. A PACIFIC TROUGH AND COLD FRONT WILL MOVE ACROSS
THE AREA TODAY. THE SHORT-TERM MODELS ARE CAPTURING THE CURRENT
SITUATION FAIRLY WELL AND IN GOOD AGREEMENT. SATELLITE AND SURFACE
ANALYSIS SHOW THE FRONT OVER EXTREME WESTERN UT EARLY THIS MORNING.
PREFRONTAL...WARM ADVECTION RELATED MID CLOUDS WILL CONTINUE
FLOWING OVER THE FORECAST AREA THIS MORNING. THE LOWEST CLOUD
BASES DETECTED OVER THE CWA HAS BEEN 11K FT SO FAR...SO LITTLE OR
NO PRECIP REACHING THE GROUND FROM THESE CLOUDS.
THE RUC SHOWS THE FRONT JUST ENTERING THE EASTERN UT PORTION OF THE
CWA ABOUT NOON. THE FRONT SHOULD REACH THE CO/UT BORDER AROUND
00Z... SO MOST OF TODAY SHOULD BE PREFRONTAL WITH STRONG SW WINDS
AND WARM AND DRY CONDITIONS. HAVE CONTINUED THE RED FLAG WARNING
FOR MOST OF WESTERN CO...BUT CANCELLED THE PORTION IN ROUTT COUNTY
AND THE FLATTOPS AS BELIEVE THE RH WILL NOT LOWER ENOUGH.
UPPER TROUGH WILL BE MOVING ACROSS OUR CWA TONIGHT AND LATEST
MODELS HAVE FOLLOWED TREND OF PREVIOUS RUNS WITH MUCH SIMILARITY.
CONFIDENCE RATHER HIGH ON THE TIMING..INTENSITY...AND MOISTURE
CONTENT FOR OUR CWA. THEREFORE...SIGNIFICANTLY BOOSTED POPS
OVERNIGHT THROUGHOUT THE NORTHERN AND MOST CENTRAL ZONES OF
WESTERN COLORADO. FOR NW COLORADO MOUNTAIN ZONES RAISED THEM FROM
SLIGHT CHANCE TO LIKELY CATEGORIES FROM MIDNIGHT THROUGH SUNRISE.
EXPECT THOSE ZONES TO GENERALLY RECEIVE 0.15 TO 0.25 OF AN INCH OF
WATER.
ALTHOUGH MOISTURE SHOULD GRADUALLY DECREASE FROM THE WEST ACROSS OUR
CWA ON SATURDAY AS THE UPPER TROUGH MOVES EAST...EXPECT SOME
LINGERING SHOWERS MAINLY ON UPWIND SIDE OF THE NORTHERN AND CENTRAL
MOUNTAINS OF WESTERN COLORADO. SHOULD BE MUCH COOLER THROUGHOUT OUR
CWA ON SATURDAY...WITH THICKNESS VALUES EXPECTED TO DROP ABOUT
90-100 METERS FROM FRIDAY...RESULTING IN MAX TEMPERATURES ON
SATURDAY GENERALLY 5 TO 10 DEGREES COOLER THAN FRIDAY.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 411 AM MDT FRI MAY 18 2012
MIGRATORY UPPER RIDGE MOVES INTO OUR AREA BY SUNDAY WITH MUCH DRIER
AIR FOR OUR REGION. WARM AIR ADVECTION LIKELY TO RESULT IN MAX
TEMPERATURES 5 TO 10 DEGREES WARMER THAN SATURDAY THROUGHOUT OUR CWA.
THE RIDGELINE WILL PASS EAST OF THE AREA MONDAY WITH INCREASING SW
FLOW ALOFT THEREAFTER AS THE NEXT PACIFIC TROUGH MOVES ONSHORE.
THIS TROUGH IS EXPECTED TO BEGIN AFFECTING NORTHERN UT TUE THEN
PUSH THROUGH THE FORECAST AREA TUE NIGHT. THE MAIN JET AXIS IS
PROGGED TO REMAIN OVER THE AREA TUE THROUGH FRI. A SERIES OF
MODERATE PACIFIC SYSTEM WILL MOVE THROUGH DURING THE WEEK
BEGINNING TUE NIGHT AND WED...THEN AGAIN WED NIGHT AND THU.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1049 AM MDT FRI MAY 18 2012
THE FIRST WAVE OF CLOUD AND ISOLATED SHOWERS/VIRGA IS PASSING OVER
THE COLORADO MOUNTAINS LATE THIS MORNING. THE MAIN THREAT WILL BE
SHIFTING AND GUSTY WINDS NEAR THE SHOWERS...OTHERWISE THE STRONGER
WESTERLY FLOW ALOFT SHOULD MIX DOWN TO THE VALLEYS WITH CLEARING
EARLY THIS AFTERNOON. THIS ADDED SUNSHINE AND APPROACHING FRONT
WILL LEAD TO AN INCREASE IN CONVECTION THIS LATE THIS AFTERNOON
AND EVENING. VFR CONDITIONS SHOULD STILL PREVAIL AT THE AREA
TERMINALS...BUT PASSING SHOWERS OR STORMS WILL BE CAPABLE OF
STRONG...ERRATIC WIND GUSTS. MVFR CONDITIONS AND LOCAL MOUNTAIN
OBSCURATIONS WILL BE POSSIBLE AS THE CONVECTION ORGANIZES THIS
AFTERNOON. IMPROVING CONDITIONS ARE EXPECTED OVERNIGHT AS THE COLD
FRONT AND UPPER SUPPORT SHIFT EAST OF THE MOUNTAINS.
&&
.FIRE WEATHER...
ISSUED AT 411 AM MDT FRI MAY 18 2012
WITH THE TROUGH AND COLD FRONT TODAY AND THIS EVENING...STRONG
SOUTHWEST WINDS WILL MIX TO THE SURFACE BY MID AND LATE MORNING.
RELATIVE HUMIDITIES AT 15% OR LESS WILL BECOME WIDESPREAD LATE THIS
MORNING AS WELL. HAVE CONTINUED THE RED FLAG WARNING FOR MOST OF
THE AREA...BUT HAVE CANCELLED THE PORTION OF THE WARNING IN ZONE
201...ROUTT COUNTY AND PORTIONS OF THE FLAT TOPS...AS THE HUMIDITY
DOESN`T SEEM TO GET LOW ENOUGH. AS THE FRONT MOVES THROUGH...
SURFACE WINDS SHOULD SHIFT ABRUPTLY TO THE NORTHWEST.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...RED FLAG WARNING UNTIL 10 PM MDT THIS EVENING FOR COZ203-207-290-
292-293.
UT...NONE.
&&
$$
UPDATE...JDC
SHORT TERM...CC/JP
LONG TERM...JP/CC
AVIATION...15
FIRE WEATHER...CC
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1049 AM MDT FRI MAY 18 2012
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 411 AM MDT FRI MAY 18 2012
TODAY...CRITICAL FIRE WEATHER CONDITIONS WILL DEVELOP OVER MUCH OF
THE FORECAST AREA BEGINNING LATE THIS MORNING AND CONTINUING INTO
THIS EVENING. A PACIFIC TROUGH AND COLD FRONT WILL MOVE ACROSS
THE AREA TODAY. THE SHORT-TERM MODELS ARE CAPTURING THE CURRENT
SITUATION FAIRLY WELL AND IN GOOD AGREEMENT. SATELLITE AND SURFACE
ANALYSIS SHOW THE FRONT OVER EXTREME WESTERN UT EARLY THIS MORNING.
PREFRONTAL...WARM ADVECTION RELATED MID CLOUDS WILL CONTINUE
FLOWING OVER THE FORECAST AREA THIS MORNING. THE LOWEST CLOUD
BASES DETECTED OVER THE CWA HAS BEEN 11K FT SO FAR...SO LITTLE OR
NO PRECIP REACHING THE GROUND FROM THESE CLOUDS.
THE RUC SHOWS THE FRONT JUST ENTERING THE EASTERN UT PORTION OF THE
CWA ABOUT NOON. THE FRONT SHOULD REACH THE CO/UT BORDER AROUND
00Z... SO MOST OF TODAY SHOULD BE PREFRONTAL WITH STRONG SW WINDS
AND WARM AND DRY CONDITIONS. HAVE CONTINUED THE RED FLAG WARNING
FOR MOST OF WESTERN CO...BUT CANCELLED THE PORTION IN ROUTT COUNTY
AND THE FLATTOPS AS BELIEVE THE RH WILL NOT LOWER ENOUGH.
UPPER TROUGH WILL BE MOVING ACROSS OUR CWA TONIGHT AND LATEST
MODELS HAVE FOLLOWED TREND OF PREVIOUS RUNS WITH MUCH SIMILARITY.
CONFIDENCE RATHER HIGH ON THE TIMING..INTENSITY...AND MOISTURE
CONTENT FOR OUR CWA. THEREFORE...SIGNIFICANTLY BOOSTED POPS
OVERNIGHT THROUGHOUT THE NORTHERN AND MOST CENTRAL ZONES OF
WESTERN COLORADO. FOR NW COLORADO MOUNTAIN ZONES RAISED THEM FROM
SLIGHT CHANCE TO LIKELY CATEGORIES FROM MIDNIGHT THROUGH SUNRISE.
EXPECT THOSE ZONES TO GENERALLY RECEIVE 0.15 TO 0.25 OF AN INCH OF
WATER.
ALTHOUGH MOISTURE SHOULD GRADUALLY DECREASE FROM THE WEST ACROSS OUR
CWA ON SATURDAY AS THE UPPER TROUGH MOVES EAST...EXPECT SOME
LINGERING SHOWERS MAINLY ON UPWIND SIDE OF THE NORTHERN AND CENTRAL
MOUNTAINS OF WESTERN COLORADO. SHOULD BE MUCH COOLER THROUGHOUT OUR
CWA ON SATURDAY...WITH THICKNESS VALUES EXPECTED TO DROP ABOUT
90-100 METERS FROM FRIDAY...RESULTING IN MAX TEMPERATURES ON
SATURDAY GENERALLY 5 TO 10 DEGREES COOLER THAN FRIDAY.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 411 AM MDT FRI MAY 18 2012
MIGRATORY UPPER RIDGE MOVES INTO OUR AREA BY SUNDAY WITH MUCH DRIER
AIR FOR OUR REGION. WARM AIR ADVECTION LIKELY TO RESULT IN MAX
TEMPERATURES 5 TO 10 DEGREES WARMER THAN SATURDAY THROUGHOUT OUR CWA.
THE RIDGELINE WILL PASS EAST OF THE AREA MONDAY WITH INCREASING SW
FLOW ALOFT THEREAFTER AS THE NEXT PACIFIC TROUGH MOVES ONSHORE.
THIS TROUGH IS EXPECTED TO BEGIN AFFECTING NORTHERN UT TUE THEN
PUSH THROUGH THE FORECAST AREA TUE NIGHT. THE MAIN JET AXIS IS
PROGGED TO REMAIN OVER THE AREA TUE THROUGH FRI. A SERIES OF
MODERATE PACIFIC SYSTEM WILL MOVE THROUGH DURING THE WEEK
BEGINNING TUE NIGHT AND WED...THEN AGAIN WED NIGHT AND THU.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1049 AM MDT FRI MAY 18 2012
THE FIRST WAVE OF CLOUD AND ISOLATED SHOWERS/VIRGA IS PASSING OVER
THE COLORADO MOUNTAINS LATE THIS MORNING. THE MAIN THREAT WILL BE
SHIFTING AND GUSTY WINDS NEAR THE SHOWERS...OTHERWISE THE STRONGER
WESTERLY FLOW ALOFT SHOULD MIX DOWN TO THE VALLEYS WITH CLEARING
EARLY THIS AFTERNOON. THIS ADDED SUNSHINE AND APPROACHING FRONT
WILL LEAD TO AN INCREASE IN CONVECTION THIS LATE THIS AFTERNOON
AND EVENING. VFR CONDITIONS SHOULD STILL PREVAIL AT THE AREA
TERMINALS...BUT PASSING SHOWERS OR STORMS WILL BE CAPABLE OF
STRONG...ERRATIC WIND GUSTS. MVFR CONDITIONS AND LOCAL MOUNTAIN
OBSCURATIONS WILL BE POSSIBLE AS THE CONVECTION ORGANIZES THIS
AFTERNOON. IMPROVING CONDITIONS ARE EXPECTED OVERNIGHT AS THE COLD
FRONT AND UPPER SUPPORT SHIFT EAST OF THE MOUNTAINS.
&&
.FIRE WEATHER...
ISSUED AT 411 AM MDT FRI MAY 18 2012
WITH THE TROUGH AND COLD FRONT TODAY AND THIS EVENING...STRONG
SOUTHWEST WINDS WILL MIX TO THE SURFACE BY MID AND LATE MORNING.
RELATIVE HUMIDITIES AT 15% OR LESS WILL BECOME WIDESPREAD LATE THIS
MORNING AS WELL. HAVE CONTINUED THE RED FLAG WARNING FOR MOST OF
THE AREA...BUT HAVE CANCELLED THE PORTION OF THE WARNING IN ZONE
201...ROUTT COUNTY AND PORTIONS OF THE FLAT TOPS...AS THE HUMIDITY
DOESN`T SEEM TO GET LOW ENOUGH. AS THE FRONT MOVES THROUGH...
SURFACE WINDS SHOULD SHIFT ABRUPTLY TO THE NORTHWEST.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...RED FLAG WARNING UNTIL 10 PM MDT THIS EVENING FOR COZ203-207-290-
292-293.
UT...NONE.
&&
$$
SHORT TERM...CC/JP
LONG TERM...JP/CC
AVIATION...15
FIRE WEATHER...CC
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
411 AM MDT FRI MAY 18 2012
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 411 AM MDT FRI MAY 18 2012
TODAY...CRITICAL FIRE WEATHER CONDITIONS WILL DEVELOP OVER MUCH OF
THE FORECAST AREA BEGINNING LATE THIS MORNING AND CONTINUING INTO
THIS EVENING. A PACIFIC TROUGH AND COLD FRONT WILL MOVE ACROSS
THE AREA TODAY. THE SHORT-TERM MODELS ARE CAPTURING THE CURRENT
SITUATION FAIRLY WELL AND IN GOOD AGREEMENT. SATELLITE AND SURFACE
ANALYSIS SHOW THE FRONT OVER EXTREME WESTERN UT EARLY THIS MORNING.
PREFRONTAL...WARM ADVECTION RELATED MID CLOUDS WILL CONTINUE
FLOWING OVER THE FORECAST AREA THIS MORNING. THE LOWEST CLOUD
BASES DETECTED OVER THE CWA HAS BEEN 11K FT SO FAR...SO LITTLE OR
NO PRECIP REACHING THE GROUND FROM THESE CLOUDS.
THE RUC SHOWS THE FRONT JUST ENTERING THE EASTERN UT PORTION OF THE
CWA ABOUT NOON. THE FRONT SHOULD REACH THE CO/UT BORDER AROUND
00Z... SO MOST OF TODAY SHOULD BE PREFRONTAL WITH STRONG SW WINDS
AND WARM AND DRY CONDITIONS. HAVE CONTINUED THE RED FLAG WARNING
FOR MOST OF WESTERN CO...BUT CANCELLED THE PORTION IN ROUTT COUNTY
AND THE FLATTOPS AS BELIEVE THE RH WILL NOT LOWER ENOUGH.
UPPER TROUGH WILL BE MOVING ACROSS OUR CWA TONIGHT AND LATEST
MODELS HAVE FOLLOWED TREND OF PREVIOUS RUNS WITH MUCH SIMILARITY.
CONFIDENCE RATHER HIGH ON THE TIMING..INTENSITY...AND MOISTURE
CONTENT FOR OUR CWA. THEREFORE...SIGNIFICANTLY BOOSTED POPS
OVERNIGHT THROUGHOUT THE NORTHERN AND MOST CENTRAL ZONES OF
WESTERN COLORADO. FOR NW COLORADO MOUNTAIN ZONES RAISED THEM FROM
SLIGHT CHANCE TO LIKELY CATEGORIES FROM MIDNIGHT THROUGH SUNRISE.
EXPECT THOSE ZONES TO GENERALLY RECEIVE 0.15 TO 0.25 OF AN INCH OF
WATER.
ALTHOUGH MOISTURE SHOULD GRADUALLY DECREASE FROM THE WEST ACROSS OUR
CWA ON SATURDAY AS THE UPPER TROUGH MOVES EAST...EXPECT SOME
LINGERING SHOWERS MAINLY ON UPWIND SIDE OF THE NORTHERN AND CENTRAL
MOUNTAINS OF WESTERN COLORADO. SHOULD BE MUCH COOLER THROUGHOUT OUR
CWA ON SATURDAY...WITH THICKNESS VALUES EXPECTED TO DROP ABOUT
90-100 METERS FROM FRIDAY...RESULTING IN MAX TEMPERATURES ON
SATURDAY GENERALLY 5 TO 10 DEGREES COOLER THAN FRIDAY.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 411 AM MDT FRI MAY 18 2012
MIGRATORY UPPER RIDGE MOVES INTO OUR AREA BY SUNDAY WITH MUCH DRIER
AIR FOR OUR REGION. WARM AIR ADVECTION LIKELY TO RESULT IN MAX
TEMPERATURES 5 TO 10 DEGREES WARMER THAN SATURDAY THROUGHOUT OUR CWA.
THE RIDGELINE WILL PASS EAST OF THE AREA MONDAY WITH INCREASING SW
FLOW ALOFT THEREAFTER AS THE NEXT PACIFIC TROUGH MOVES ONSHORE.
THIS TROUGH IS EXPECTED TO BEGIN AFFECTING NORTHERN UT TUE THEN
PUSH THROUGH THE FORECAST AREA TUE NIGHT. THE MAIN JET AXIS IS
PROGGED TO REMAIN OVER THE AREA TUE THROUGH FRI. A SERIES OF
MODERATE PACIFIC SYSTEM WILL MOVE THROUGH DURING THE WEEK
BEGINNING TUE NIGHT AND WED...THEN AGAIN WED NIGHT AND THU.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 411 AM MDT FRI MAY 18 2012
VFR CONDITIONS WILL PREVAIL TODAY WITH MAIN MID AND HIGH LEVEL
CLOUDS OVER THE AREA. THERE IS A SLIGHT CHANCE OF A SHOWER TODAY
BUT CEILINGS AND VSBY SHOULD REMAIN IN THE VFR CATEGORY.
&&
.FIRE WEATHER...
ISSUED AT 411 AM MDT FRI MAY 18 2012
WITH THE TROUGH AND COLD FRONT TODAY AND THIS EVENING...STRONG
SOUTHWEST WINDS WILL MIX TO THE SURFACE BY MID AND LATE MORNING.
RELATIVE HUMIDITIES AT 15% OR LESS WILL BECOME WIDESPREAD LATE THIS
MORNING AS WELL. HAVE CONTINUED THE RED FLAG WARNING FOR MOST OF
THE AREA...BUT HAVE CANCELLED THE PORTION OF THE WARNING IN ZONE
201...ROUTH COUNTY AND PORTIONS OF THE FLATTAPS...AS THE HUMIDITY
DOESN`T SEEM TO GET LOW ENOUGH. AS THE FRONT MOVES THROUGH...
SURFACE WINDS SHOULD SHIFT ABRUPTLY TO THE NORTHWEST.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...RED FLAG WARNING FROM 11 AM THIS MORNING TO 10 PM MDT THIS
EVENING FOR COZ203-207-290-292-293.
UT...NONE.
&&
$$
SHORT TERM...CC
LONG TERM...15
AVIATION...CC
FIRE WEATHER...CC
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
644 AM CDT FRI MAY 18 2012
.UPDATE...
OBS DATA THROUGH 11Z CONTINUES TO SHOW UPPER 30S AND LOWER 40 DEW
POINTS ACROSS THE AREA. THE ATMOSPHERE IS NOW HEATING AND DEEPER
MIXING WILL BEGIN ONCE THE INVERSION BREAKS AROUND MID MORNING.
PRELIMINARY SOUNDING DATA RECEIVED SO FAR FROM THE 12Z FLIGHT
SUGGESTS WE SHOULD EASILY MIX TO 850MB TODAY WHICH WOULD KEEP DEW
POINTS WHERE THEY ARE RIGHT NOW OR POSSIBLY DROP FURTHER IN SPITE
OF THE MOISTURE SLOWLY BEING ADVECTED INTO THE AREA. SOME MINOR
TWEEKS TO THE FCST WILL BE DONE FOR DEW POINTS THAT MAY OR MAY NOT
INCLUDE A SLIGHT CHANGE TO MAX TEMPS. ..08..
&&
.AVIATION...
VFR WX WILL BE SEEN THROUGH 12Z/19. RADAR WIND PROFILES CONTINUE
TO SUGGEST LLWS ACROSS EASTERN IOWA/NORTHERN ILLINOIS BUT THIS HAS
NOT BEEN SUBSTANTIATED BY ACFT. RAP MODEL TRENDS THE PAST SEVERAL
HOURS INDICATE LOWER WIND SPEEDS AT 1-2KFT AGL. THUS THE LLWS
THREAT WAS REMOVED FROM THE 12Z TAFS AS THE THREAT APPEARS TO BE MARGINAL
AT BEST. THERE IS STILL A CONCERN FOR LLWS DVLPG AFT 03Z/19 BUT IT
WAS LEFT OUT OF THE 12Z TAFS. ..08..
&&
.PREV DISCUSSION... /ISSUED 257 AM CDT FRI MAY 18 2012/
SYNOPSIS...
06Z SFC ANALYSIS HAS HIGH PRESSURE OVER THE EASTERN GREAT LAKES WITH
A COLD FRONT FROM WESTERN MINNESOTA INTO WYOMING. DEW POINTS WERE IN
THE 30S ACROSS THE GREAT LAKES WITH A NARROW FEED OF 50 DEW POINTS
FROM THE SOUTHERN PLAINS INTO WESTERN MINNESOTA. SATELLITE TRENDS
INDICATE MAINLY CI/CS BLOW OFF OVER THE AREA FROM EARLIER CONVECTION
IN THE PLAINS.
SHORT TERM...TODAY AND TONIGHT
QUIET AND DRY CONDITIONS WILL CONTINUE TODAY AND TONIGHT ACROSS THE
AREA. THE DRY ATMOSPHERE COMBINED WITH THE NOW DRY GROUND WILL ALLOW
LARGER THAN NORMAL DIURNAL TRENDS ACROSS THE AREA.
ALTHOUGH MOISTURE WILL BE TRANSPORTED INTO THE CWFA DURING THE
DAY...DEEP MIXING WILL CAUSE OVERALL MOISTURE LEVELS TO DROP DURING
THE DAY. BASED ON WHAT OCCURRED YESTERDAY WEST OF THE AREA...DEW
POINTS HOLDING OR DROPPING INTO THE 40-45 DEGREE RANGE SEEMS VERY
PLAUSIBLE. IT IS NOT OUT OF THE REALM OF POSSIBILITY THAT DEW POINTS
MAY DROP INTO THE UPPER 30S IN THE EASTERN CWFA. ..08..
LONG TERM...SATURDAY THROUGH NEXT THURSDAY
A WARM PERIOD OF WEATHER WILL PERSIST INTO SUNDAY...FOLLOWED BY A
BRIEF COOL DOWN FOR MONDAY INTO TUESDAY...FOLLOWED BY MORE WARMING.
THIS PORTION OF THE FORECAST IS REASONABLY CONFIDENT...BUT LITTLE
CONFIDENCE EXISTS ON TIMING AND COVERAGE OF RAINFALL CHANCES.
AS NOTED IN THE SHORT TERM...MOISTURE WITHIN MODEL GUIDANCE IS
SUSPECT TO SAY THE LEAST WITH THE GULF WEAKLY SUPPORTING MOISTURE
TRANSPORT THIS WEEKEND. DESPITE SLOW MOVEMENT OF THE FRONT SATURDAY
NIGHT INTO SUNDAY NIGHT OVER THE CWA...WEAK FORCING AND ONLY MODEST
MOISTURE LEAD ME TO BELIEVE THAT RAINFALL MAY NOT BE VERY IMPRESSIVE
AT ALL. SOME DIURNAL FLUX UPWARD IN PRECIP POTENTIAL MAY OCCUR ALONG
AND EAST OF THE MISSISSIPPI RIVER SUNDAY AFTERNOON...BUT THIS OF LOW
CONFIDENCE. WILL STAY CLOSE TO HPC GUIDANCE ON RAIN AMOUNTS.
MONDAY THROUGH WEDNESDAY APPEAR DRY...AS HIGH PRESSURE MIGRATES WEST
TO EAST OVER THE CWA. MONDAY MAY DEAL WITH SOME MID CLOUDS...AND IS
CERTAINLY THE COOLEST DAY...WITH HIGHS MAINLY IN THE LOWER 70S.
TUESDAY INTO WEDNESDAY...ROBUST WARMING WILL SEE A DAY IN THE MID
70S TUESDAY AND AROUND 80 WEDNESDAY.
PRECIP CHANCES RETURN FOR WEDNESDAY NIGHT THROUGH THURSDAY. THE
PATTERN WILL BE ACTIVE NEARBY...BUT AS MUCH GUIDANCE SUPPORTS STORMS
OVER THE DVN CWA...THERE IS MORE SUGGESTING THE TROF WILL BE MAINLY
WEST...WITH UPPER RIDGING AND CAPPING FOUND THIS FAR EAST. SO...WE
WILL BE EITHER WARM AND STORM BEGINNING WEDNESDAY NIGHT...OR JUST
PLAIN HOT AND DRY. ERVIN
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
959 PM CDT SAT MAY 19 2012
.UPDATE...
STRONG/SEVERE STORMS ARE HANGING AROUND A BIT LONGER THAN
PREVIOUSLY EXPECTED...AND ARE REMAINING FAIRLY STOUT FURTHER EAST
THAN PREVIOUSLY THOUGHT...DESPITE SHARPLY DECREASING INSTABILITY
EAST OF THE FLINT HILLS AND A STOUT CAPPING INVERSION PER TOPEKA
AND SPRINGFIELD EVENING SOUNDINGS. ONE POSSIBILITY FOR THE RECENT
70-80 MPH WIND GUST OVER GREENWOOD COUNTY IS EVAPORATIVE COOLING
DUE TO DRY LOW-LEVELS. ACTIVITY OVER SOUTH-CENTRAL KANSAS ALONG
THE OK BORDER IS STILL ABLE TO TAP A MODESTLY UNSTABLE
AIRMASS TO THE SOUTH OF THE COLD FRONT...SO STRONG/SEVERE MAKES
SENSE THERE. OVERALL TREND SHOULD BE FOR A GRADUAL DECREASE IN
THUNDERSTORM INTENSITY...ALTHOUGH COVERAGE COULD STAY UP DUE TO
LOW-LEVEL JET ACTING ON COLD FRONT. WILL CONTINUE SEVERE
THUNDERSTORM WATCH GENERALLY SOUTHEAST OF THE KS TURNPIKE IN
EFFECT UNTIL 4 AM...ALTHOUGH ENVISION OVERNIGHT SHIFT WILL BE ABLE
TO CANCEL EARLY.
ADK
&&
.PREV DISCUSSION... /ISSUED 805 PM CDT SAT MAY 19 2012/
UPDATE...
IT APPEARS TORNADO THREAT IS RAPIDLY WANING AS LOW-LEVEL CAPE
DECREASES DUE TO ONSET OF DIURNAL COOLING.
ADDITIONALLY...MAGNITUDE OF SEVERE WEATHER SHOULD GRADUALLY WANE
WITH EASTWARD EXTENT...AS LOW-LEVEL THETA-E AND INSTABILITY DROPS
OFF SHARPLY EAST OF THE FLINT HILLS. HOWEVER...DID END UP
INCLUDING GREENWOOD-ELK-CHAUTAUQUA-COWLEY COUNTIES IN THE SEVERE
THUNDERSTORM WATCH UNTIL 10 PM. SUB-SEVERE SHOWERS/THUNDERSTORMS
COULD CONTINUE REDEVELOPING/FESTERING OVER PORTIONS OF
CENTRAL/SOUTH- CENTRAL KS IN WAKE OF THE SURFACE COLD
FRONT...ALONG ELEVATED FRONTAL SURFACE PUSHING EAST.
ADK
PREV DISCUSSION... /ISSUED 659 PM CDT SAT MAY 19 2012/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
SCATTERED STRONG/SEVERE STORMS ALONG AN EASTWARD ADVANCING COLD
FRONT WILL CONTINUE MOVING EAST/NORTHEAST THIS
EVENING...AFFECTING KSLN-KICT WITHIN THE NEXT FEW HOURS AND
POSSIBLY KHUT. VERY HEAVY RAIN...GUSTY WINDS AND HAIL CAN BE
EXPECTED. THREAT SHOULD PASS KHUT-KICT-KSLN BY 02-03Z OR SO...WITH
THUNDERSTORMS MAYBE NOT EVEN MAKING IT TO KCNU. WILL CONTINUE TO
MONITOR.
ADK
PREV DISCUSSION... /ISSUED 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 LATTER 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 / 60 20 10 0
HUTCHINSON 56 78 54 80 / 60 10 0 0
NEWTON 57 77 53 78 / 60 20 10 0
ELDORADO 59 78 54 79 / 60 20 10 0
WINFIELD-KWLD 61 79 58 80 / 60 30 20 10
RUSSELL 52 77 51 81 / 10 10 0 0
GREAT BEND 53 78 52 81 / 10 10 0 0
SALINA 56 78 51 80 / 60 10 0 0
MCPHERSON 57 77 52 79 / 60 10 0 0
COFFEYVILLE 65 81 59 79 / 50 40 30 10
CHANUTE 64 79 57 78 / 50 40 10 10
IOLA 64 78 57 77 / 50 40 10 10
PARSONS-KPPF 65 80 58 78 / 50 40 20 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...CORRECTED
NWS DODGE CITY KS
813 PM CDT SAT MAY 19 2012
...UPDATED THE SHORT TERM FORECAST...
.UPDATE... ISSUED AT 806 PM CDT SAT MAY 19 2012
PER THE HRRR MODEL, I UPDATED THE FORECAST THROUGH 09Z TONIGHT, TO
ADD A SLIGHT CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS WEST OF
A DIGHTON TO NEAR DODGE CITY TO MEADE LINE. DO NOT EXPECT ANY
SEVERE STORMS, BUT THESE SHOWERS COULD PRODUCE 0.01 TO 0.03 INCHES
OF RAIN IN OUR SOUTHWEST. HIGH PRESSURE WILL RULE AT THE SURFACE,
BUT A MID LEVEL SHORT WAVE WILL DRIVE SOME CONVECTION INTO OUR
SOUTHWEST TONIGHT. WIDELY SCATTERED STORMS ARE ALREADY EVIDENT
OVER SOUTHEASTERN COLORADO.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 343 PM CDT SAT MAY 19 2012
A SHORTWAVE TROUGH WAS TRAVERSING THE HIGH PLAINS OF WESTERN KANSAS
THIS AFTERNOON. THUNDERSTORMS DEVELOPED AHEAD OF THE POTENTIAL
VORTICITY ANOMALY AND 500MB COLD POOL BY LATE MORNING IN EASTERN
COLORADO AND PROGRESSED INTO NORTHWEST KANSAS EARLY THIS AFTERNOON.
THESE STORMS WILL PROBABLY STAY JUST TO OUR NORTH FOR THE REMAINDER
OF THE AFTERNOON. SURFACE WINDS WILL REACH NEAR 30 KTS BEHIND THE
COLD FRONT AS THIS PROGRESSIVE SHORTWAVE TROUGH PASSES. SO A WIND
ADVISORY WAS ISSUED FOR WESTERN AND CENTRAL KANSAS THROUGH 00Z.
THUNDERSTORMS WILL ALSO DEVELOP ALONG THE COLD FRONT FROM CENTRAL
KANSAS INTO SOUTH CENTRAL KANSAS THIS AFTERNOON. LOW LEVEL MOISTURE
FROM THE GULF OF MEXICO WAS VERY MARGINAL, WITH DEWPOINTS IN THE
MID 50S TO NEAR 60 ACROSS SOUTH CENTRAL KANSAS. SURFACE BASED CAPE
VALUES WILL BE AROUND 2000 J/KG AT BEST AND THE STORMS WILL STILL BE
A LITTLE HIGH BASED. HAIL TO QUARTER SIZE AND POSSIBLY AS LARGE AS
GOLF BALLS CAN BE EXPECTED WITH THE STRONGEST STORMS.
SURFACE HIGH PRESSURE WILL BUILD INTO WESTERN KANSAS TONIGHT AND
SUNDAY BEHIND THE SHORTWAVE TROUGH. THE SURFACE FRONT WILL BE ACROSS
SOUTHERN OKLAHOMA BY SUNDAY AFTERNOON. BY SUNDAY MORNING,
TEMPERATURES SHOULD DROP INTO THE UPPER 40S TO LOWER 50S AS DRY AIR
MOVES IN AND WINDS BECOME LIGHT. WITH NO SURFACE BASED CAPE OR
CONVERGENCE, THUNDERSTORMS ARE NOT EXPECTED ON SUNDAY. THERE COULD
BE A FEW MID-LEVEL CLOUDS PERSISTING AS THE MID LEVELS ARE NOT
PROGGED TO DRY OUT COMPLETELY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 247 PM CDT SAT MAY 19 2012
UPPER LEVEL RIDGING WILL BUILD ACROSS THE ROCKIES AS THE LONG TERM
PERIOD BEGINS THEN SHIFT INTO THE CENTRAL PLAINS BY TUESDAY.
MEANWHILE, AN UPPER LEVEL LONGWAVE TROUGH WILL WILL BE MOVING INTO
THE PACIFIC NORTHWEST MONDAY THEN INTO THE NORTHERN ROCKIES
WEDNESDAY. AT THE SURFACE, PARTLY CLOUDY SKIES AND DRY CONDITIONS
WILL PREVAIL THROUGH MONDAY NIGHT WITH WINDS INITIALLY FROM THE
EAST, SHIFTING TO THE SOUTHEAST MONDAY AFTERNOON THROUGH TUESDAY
MORNING. THIS UPSLOPE COMPONENT OF THE WIND WILL ALLOW DEWPOINTS TO
RISE BACK UP INTO THE LOWER 50S BY TUESDAY MORNING. A WEAK FRONTAL
BOUNDARY WILL MOVE ACROSS WESTERN KANSAS ON TUESDAY INCREASING LIFT
AND SHIFTING THE WINDS TO THE SOUTHWEST BEHIND IT. I HAVE CONTINUED
THE SLIGHT CHANCE OF THUNDERSTORMS THROUGHOUT THE DAY WITH A SLIGHT
INCREASE IN CLOUD COVER. SURFACE LEE TROUGHING ACROSS EASTERN
COLORADO WILL ALSO STRENGTHEN ON TUESDAY INCREASING WIND SPEEDS
ACROSS WESTERN KANSAS. AS FOR TEMPERATURES, 850 TEMPERATURES WILL
START OUT IN THE TEENS AND LOWER 20S MONDAY AFTERNOON THEN MODERATE
BACK INTO THE UPPER 20S AND POSSIBLY LOWER 30S BY WEDNESDAY
AFTERNOON. AS THIS MIXES TO THE SURFACE, HIGHS ARE EXPECTED TO START
OUT AROUND 80 ON MONDAY MODERATING UPWARD TO THE UPPER 80S AND LOWER
90S BY WEDNESDAY AFTERNOON. LOWS ARE FORECASTED TO DIP INTO THE MID
TO UPPER 50S MONDAY MORNING WITH UPPER 50S TO MID 60S TUESDAY
THROUGH WEDNESDAY MORNING.
UPPER LEVEL TROUGHING IN THE WEST CONUS WITH UPPER LEVEL RIDGING IN
THE EAST CONUS WILL CONTINUE THROUGHOUT THE REMAINDER OF THE WEEK.
THIS WILL PLACE THE HIGH PLAINS UNDER SOUTHWEST FLOW ALOFT. AT THE
SURFACE, HIGH PRESSURE IS ANTICIPATED TO BE LOCATED WELL EAST OF
KANSAS WITH WITH LEE TROUGHING CONTINUING ACROSS EASTERN COLORADO.
THIS WILL ALLOW SOUTHERLY WINDS TO CONTINUE THROUGH FRIDAY. EXTENDED
MODELS DEPICT DRY CONDITIONS ACROSS WESTERN KANSAS THROUGHOUT THE
REMAINDER OF THE WEEK WITH PARTLY CLOUDY SKIES. HOWEVER, IF AN UPPER
LEVEL SHORTWAVE MOVES UNDER AND AROUND THE AFOREMENTIONED TROUGH IT
COULD BRING ENOUGH ENERGY TO DEVELOP A FEW THUNDERSTORMS IN THE
AFTERNOON. 850 TEMPERATURES REMAIN IN THE UPPER 20S TO LOWER 30S
THROUGHOUT THE REMAINDER OF THE WEEK AND HIGHS ARE FORECASTED TO
REACH INTO THE UPPER 80S AND LOWER 90S THURSDAY AND FRIDAY. LOWS ARE
FORECASTED TO RANGE FROM THE LOWER 60S ACROSS THE KS/CO BORDER TO
AROUND 70 DEGREES ACROSS SOUTH CENTRAL KANSAS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 555 PM CDT SAT MAY 19 2012
CONDITIONS WILL REMAIN IN THE VFR CATEGORY, AS A COLD FRONT MOVES
TO THE SOUTH AND AWAY FROM THE 3 TAF SITES. HIGH PRESSURE WILL
MOVE DOWN FROM WYOMING OVER THE NEXT 24 HOURS. WINDS WILL SETTLE
DOWNWARD AND BE NORTH AT 12 TO 14 KNOTS BY 03Z. WINDS WILL SHIFT
NORTHEAST BY SUNDAY MORNING, AND A FEW MID TO HIGH LEVEL CLOUDS
WILL PASS OVER.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 51 77 55 81 / 0 0 0 10
GCK 48 76 54 81 / 20 0 10 10
EHA 49 76 56 82 / 20 0 10 20
LBL 50 77 57 82 / 20 0 10 20
HYS 49 76 53 81 / 0 0 0 10
P28 56 80 57 80 / 50 0 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BURKE
SHORT TERM...FINCH
LONG TERM...HOVORKA 42
AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
812 PM CDT SAT MAY 19 2012
...UPDATED THE SHORT TERM FORECAST...
.UPDATE... ISSUED AT 806 PM CDT SAT MAY 19 2012
PER THE HRRR MODEL, I UPDATE THE FORECAST THROUGH 09Z TONIGHT, TO
ADD A SLIGHT CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS WEST OF
A DIGHTON TO NEAR DODGE CITY TO MEADE LINE. DO NOT EXPECT ANY
SEVERE STORMS, BUT THESE SHOWERS COULD PRODUCE 0.01 TO 0.03 INCHES
OF RAIN IN OUR SOUTHWEST. HIGH PRESSURE WILL RULE AT THE SURFACE,
BUT A MID LEVEL SHORT WAVE WILL DRIVE SOME CONVECTION INTO OUR
SOUTHWEST TONIGHT. WIDELY SCATTERED STORMS ARE ALREADY EVIDENT
OVER SOUTHEASTERN COLORADO.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 343 PM CDT SAT MAY 19 2012
A SHORTWAVE TROUGH WAS TRAVERSING THE HIGH PLAINS OF WESTERN KANSAS
THIS AFTERNOON. THUNDERSTORMS DEVELOPED AHEAD OF THE POTENTIAL
VORTICITY ANOMALY AND 500MB COLD POOL BY LATE MORNING IN EASTERN
COLORADO AND PROGRESSED INTO NORTHWEST KANSAS EARLY THIS AFTERNOON.
THESE STORMS WILL PROBABLY STAY JUST TO OUR NORTH FOR THE REMAINDER
OF THE AFTERNOON. SURFACE WINDS WILL REACH NEAR 30 KTS BEHIND THE
COLD FRONT AS THIS PROGRESSIVE SHORTWAVE TROUGH PASSES. SO A WIND
ADVISORY WAS ISSUED FOR WESTERN AND CENTRAL KANSAS THROUGH 00Z.
THUNDERSTORMS WILL ALSO DEVELOP ALONG THE COLD FRONT FROM CENTRAL
KANSAS INTO SOUTH CENTRAL KANSAS THIS AFTERNOON. LOW LEVEL MOISTURE
FROM THE GULF OF MEXICO WAS VERY MARGINAL, WITH DEWPOINTS IN THE
MID 50S TO NEAR 60 ACROSS SOUTH CENTRAL KANSAS. SURFACE BASED CAPE
VALUES WILL BE AROUND 2000 J/KG AT BEST AND THE STORMS WILL STILL BE
A LITTLE HIGH BASED. HAIL TO QUARTER SIZE AND POSSIBLY AS LARGE AS
GOLF BALLS CAN BE EXPECTED WITH THE STRONGEST STORMS.
SURFACE HIGH PRESSURE WILL BUILD INTO WESTERN KANSAS TONIGHT AND
SUNDAY BEHIND THE SHORTWAVE TROUGH. THE SURFACE FRONT WILL BE ACROSS
SOUTHERN OKLAHOMA BY SUNDAY AFTERNOON. BY SUNDAY MORNING,
TEMPERATURES SHOULD DROP INTO THE UPPER 40S TO LOWER 50S AS DRY AIR
MOVES IN AND WINDS BECOME LIGHT. WITH NO SURFACE BASED CAPE OR
CONVERGENCE, THUNDERSTORMS ARE NOT EXPECTED ON SUNDAY. THERE COULD
BE A FEW MID-LEVEL CLOUDS PERSISTING AS THE MID LEVELS ARE NOT
PROGGED TO DRY OUT COMPLETELY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 247 PM CDT SAT MAY 19 2012
UPPER LEVEL RIDGING WILL BUILD ACROSS THE ROCKIES AS THE LONG TERM
PERIOD BEGINS THEN SHIFT INTO THE CENTRAL PLAINS BY TUESDAY.
MEANWHILE, AN UPPER LEVEL LONGWAVE TROUGH WILL WILL BE MOVING INTO
THE PACIFIC NORTHWEST MONDAY THEN INTO THE NORTHERN ROCKIES
WEDNESDAY. AT THE SURFACE, PARTLY CLOUDY SKIES AND DRY CONDITIONS
WILL PREVAIL THROUGH MONDAY NIGHT WITH WINDS INITIALLY FROM THE
EAST, SHIFTING TO THE SOUTHEAST MONDAY AFTERNOON THROUGH TUESDAY
MORNING. THIS UPSLOPE COMPONENT OF THE WIND WILL ALLOW DEWPOINTS TO
RISE BACK UP INTO THE LOWER 50S BY TUESDAY MORNING. A WEAK FRONTAL
BOUNDARY WILL MOVE ACROSS WESTERN KANSAS ON TUESDAY INCREASING LIFT
AND SHIFTING THE WINDS TO THE SOUTHWEST BEHIND IT. I HAVE CONTINUED
THE SLIGHT CHANCE OF THUNDERSTORMS THROUGHOUT THE DAY WITH A SLIGHT
INCREASE IN CLOUD COVER. SURFACE LEE TROUGHING ACROSS EASTERN
COLORADO WILL ALSO STRENGTHEN ON TUESDAY INCREASING WIND SPEEDS
ACROSS WESTERN KANSAS. AS FOR TEMPERATURES, 850 TEMPERATURES WILL
START OUT IN THE TEENS AND LOWER 20S MONDAY AFTERNOON THEN MODERATE
BACK INTO THE UPPER 20S AND POSSIBLY LOWER 30S BY WEDNESDAY
AFTERNOON. AS THIS MIXES TO THE SURFACE, HIGHS ARE EXPECTED TO START
OUT AROUND 80 ON MONDAY MODERATING UPWARD TO THE UPPER 80S AND LOWER
90S BY WEDNESDAY AFTERNOON. LOWS ARE FORECASTED TO DIP INTO THE MID
TO UPPER 50S MONDAY MORNING WITH UPPER 50S TO MID 60S TUESDAY
THROUGH WEDNESDAY MORNING.
UPPER LEVEL TROUGHING IN THE WEST CONUS WITH UPPER LEVEL RIDGING IN
THE EAST CONUS WILL CONTINUE THROUGHOUT THE REMAINDER OF THE WEEK.
THIS WILL PLACE THE HIGH PLAINS UNDER SOUTHWEST FLOW ALOFT. AT THE
SURFACE, HIGH PRESSURE IS ANTICIPATED TO BE LOCATED WELL EAST OF
KANSAS WITH WITH LEE TROUGHING CONTINUING ACROSS EASTERN COLORADO.
THIS WILL ALLOW SOUTHERLY WINDS TO CONTINUE THROUGH FRIDAY. EXTENDED
MODELS DEPICT DRY CONDITIONS ACROSS WESTERN KANSAS THROUGHOUT THE
REMAINDER OF THE WEEK WITH PARTLY CLOUDY SKIES. HOWEVER, IF AN UPPER
LEVEL SHORTWAVE MOVES UNDER AND AROUND THE AFOREMENTIONED TROUGH IT
COULD BRING ENOUGH ENERGY TO DEVELOP A FEW THUNDERSTORMS IN THE
AFTERNOON. 850 TEMPERATURES REMAIN IN THE UPPER 20S TO LOWER 30S
THROUGHOUT THE REMAINDER OF THE WEEK AND HIGHS ARE FORECASTED TO
REACH INTO THE UPPER 80S AND LOWER 90S THURSDAY AND FRIDAY. LOWS ARE
FORECASTED TO RANGE FROM THE LOWER 60S ACROSS THE KS/CO BORDER TO
AROUND 70 DEGREES ACROSS SOUTH CENTRAL KANSAS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 555 PM CDT SAT MAY 19 2012
CONDITIONS WILL REMAIN IN THE VFR CATEGORY, AS A COLD FRONT MOVES
TO THE SOUTH AND AWAY FROM THE 3 TAF SITES. HIGH PRESSURE WILL
MOVE DOWN FROM WYOMING OVER THE NEXT 24 HOURS. WINDS WILL SETTLE
DOWNWARD AND BE NORTH AT 12 TO 14 KNOTS BY 03Z. WINDS WILL SHIFT
NORTHEAST BY SUNDAY MORNING, AND A FEW MID TO HIGH LEVEL CLOUDS
WILL PASS OVER.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 51 77 55 81 / 0 0 0 10
GCK 48 76 54 81 / 20 0 10 10
EHA 49 76 56 82 / 20 0 10 20
LBL 50 77 57 82 / 20 0 10 20
HYS 49 76 53 81 / 0 0 0 10
P28 56 80 57 80 / 50 0 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BURKE
SHORT TERM...FINCH
LONG TERM...HOVORKA 42
AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS WICHITA KS
805 PM CDT SAT MAY 19 2012
.UPDATE...
IT APPEARS TORNADO THREAT IS RAPIDLY WANING AS LOW-LEVEL CAPE
DECREASES DUE TO ONSET OF DIURNAL COOLING.
ADDITIONALLY...MAGNITUDE OF SEVERE WEATHER SHOULD GRADUALLY WANE
WITH EASTWARD EXTENT...AS LOW-LEVEL THETA-E AND INSTABILITY DROPS
OFF SHARPLY EAST OF THE FLINT HILLS. HOWEVER...DID END UP
INCLUDING GREENWOOD-ELK-CHAUTAUQUA-COWLEY COUNTIES IN THE SEVERE
THUNDERSTORM WATCH UNTIL 10 PM. SUB-SEVERE SHOWERS/THUNDERSTORMS
COULD CONTINUE REDEVELOPING/FESTERING OVER PORTIONS OF
CENTRAL/SOUTH- CENTRAL KS IN WAKE OF THE SURFACE COLD
FRONT...ALONG ELEVATED FRONTAL SURFACE PUSHING EAST.
ADK
&&
.PREV DISCUSSION... /ISSUED 659 PM CDT SAT MAY 19 2012/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
SCATTERED STRONG/SEVERE STORMS ALONG AN EASTWARD ADVANCING COLD
FRONT WILL CONTINUE MOVING EAST/NORTHEAST THIS
EVENING...AFFECTING KSLN-KICT WITHIN THE NEXT FEW HOURS AND
POSSIBLY KHUT. VERY HEAVY RAIN...GUSTY WINDS AND HAIL CAN BE
EXPECTED. THREAT SHOULD PASS KHUT-KICT-KSLN BY 02-03Z OR SO...WITH
THUNDERSTORMS MAYBE NOT EVEN MAKING IT TO KCNU. WILL CONTINUE TO
MONITOR.
ADK
PREV DISCUSSION... /ISSUED 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 LATTER 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 / 60 20 10 0
HUTCHINSON 56 78 54 80 / 60 10 0 0
NEWTON 57 77 53 78 / 60 20 10 0
ELDORADO 59 78 54 79 / 60 20 10 0
WINFIELD-KWLD 61 79 58 80 / 60 30 20 10
RUSSELL 52 77 51 81 / 10 10 0 0
GREAT BEND 53 78 52 81 / 10 10 0 0
SALINA 56 78 51 80 / 60 10 0 0
MCPHERSON 57 77 52 79 / 60 10 0 0
COFFEYVILLE 65 81 59 79 / 40 40 30 10
CHANUTE 64 79 57 78 / 40 40 10 10
IOLA 64 78 57 77 / 40 40 10 10
PARSONS-KPPF 65 80 58 78 / 40 40 20 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
659 PM CDT SAT MAY 19 2012
.AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
SCATTERED STRONG/SEVERE STORMS ALONG AN EASTWARD ADVANCING COLD
FRONT WILL CONTINUE MOVING EAST/NORTHEAST THIS
EVENING...AFFECTING KSLN-KICT WITHIN THE NEXT FEW HOURS AND
POSSIBLY KHUT. VERY HEAVY RAIN...GUSTY WINDS AND HAIL CAN BE
EXPECTED. THREAT SHOULD PASS KHUT-KICT-KSLN BY 02-03Z OR SO...WITH
THUNDERSTORMS MAYBE NOT EVEN MAKING IT TO KCNU. WILL CONTINUE TO
MONITOR.
ADK
&&
.PREV DISCUSSION... /ISSUED 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 LATTER 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
NWS PITTSBURGH PA
1005 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/...
CI SHIELD FROM SE TS CONTINUES TO PUSH OVER THE UPPER OHIO VALLEY.
HAVE INCREASED CLOUD COVER JUST A BIT OVERNIGHT, PARTICULARLY
ACROSS THE SOUTH.
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 /02Z SUNDAY 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...UPDATED
NWS PITTSBURGH PA
639 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/...
MINOR CHANGES TO PREVIOUS FORECAST, REMOVED CLOUDS IN THE SOUTH
AND ADJUSTED HOURLY TEMPS.
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 /00Z 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 PITTSBURGH PA
332 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/...
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 /19Z FRIDAY 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 PITTSBURGH PA
210 PM EDT FRI MAY 18 2012
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE FOR QUIET WEATHER AND A WARMING TREND
THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO
INCREASE SKY GRIDS AS DIURNAL CU DEVELOPS ACROSS PORTIONS OF
NORTHERN WV.
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 12Z KPIT
SOUNDING INDICATES DEEP SUBSIDENCE AND DRY AIR ALOFT.
THE 500MB RIDGE WILL BUILD IN FURTHER INTO THE GREAT LAKES REGION
TODAY AND TONIGHT WITH ANTI-CYCLONIC FLOW ALOFT CENTERED ACROSS
NORTHERN OHIO BY 12Z SATURDAY. THIS WILL ALLOW ABUNDANT SUNSHINE TO
CONTINUE ACROSS THE REGION. HIGHS TODAY ARE A FEW DEGREES WARMER
THAN LAMP GUIDANCE, WARMING TO NEAR 80 ACROSS MUCH OF THE AREA.
WITH NEAR CALM WINDS AND CLEAR SKIES TONIGHT, RADIATIONAL COOLING
WILL ALLOW FOR TEMPERATURES TO STEADILY DROP OFF. OVERNIGHT LOWS
WILL RANGE FROM THE MID 40S ACROSS THE I-80 CORRIDOR AND EASTERN
RIDGES TO THE LOWER 50S ACROSS PORTIONS OF EASTERN OHIO AND
NORTH-CENTRAL WV.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
HIGH PRESSURE RIDGE WILL CONTINUE TO DOMINATE THE FORECAST THROUGH
AT LEAST SUNDAY AS SUGGESTED BY MOST GLOBAL MODELS. AS THE RIDGE
CONTINUES TO BUILD AND SLIDE TOWARD THE COAST...850MB TEMPERATURES
ALOFT WILL REACH 16C...WHICH SHOULD HELP TO BRING TEMPERATURES 5
TO 10 DEGREES ABOVE NORMAL SATURDAY AND SUNDAY. THOUGH CURRENT
FORECAST HIGHS ARE SLIGHTLY BELOW MOS GUIDANCE...WHICH LOOKED A
LITTLE TOO HIGH.
MODEL AGREEMENT THEN DIVERGES INTO SUNDAY NIGHT AND MONDAY ON THE
TIMING AND PLACEMENT OF THE MID-UPPER LEVEL CLOSED LOW OVER THE
SOUTHEAST. THERE CONTINUES TO BE A GROUPING BETWEEN THE
NAM/CANADIAN AND GFS/ECMWF. SINCE NOT MUCH HAS CHANGED IN THE
DETERMINISTIC MODELS WITH THE NEW RUNS...OPTED TO CONTINUE THE DRY
FORECAST FOR SUNDAY NIGHT...GRADUALLY BRINGING IN POPS FROM BOTH
THE EAST WITH THE RETROGRADING LOW AND THE WEST WITH THE SLOW
MOVING COLD FRONT BY LATE MONDAY. THIS WAS CLOSEST TO GFS/ECMWF
AND SREF ENSEMBLE MEAN THROUGH THE PERIOD. KEPT TEMPERATURES A FEW
DEGREES ABOVE MOS GUIDANCE AND STILL A FEW DEGREES ABOVE NORMAL
MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
WITH CONTINUED MODEL DISAGREEMENT...MAINTAINED A FORECAST CLOSE TO
HPC GUIDANCE WITH HEAVY EMPHASIS ON THE MOST RECENT GFS RUN WHICH
BRINGS THE COLD FRONT THROUGH THE REGION THE FASTEST MONDAY NIGHT
AND TUESDAY.
A SURFACE RIDGE PROGGED TO BUILD IN FROM THE MIDWEST LATE WEDNESDAY
INTO THURSDAY SHOULD PROVIDE A RETURN TO DRY WEATHER FOR THE MIDDLE
OF THE WEEK.
TEMPERATURES ARE FORECAST TO RANGE FROM 5 TO 10 DEGREES ABOVE NORMAL
THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD AS SURFACE HIGH
PRESSURE SLIDES EASTWARD FROM THE GREAT LAKES AND OVER NEW ENGLAND.
LGT NE SFC WND WL VEER TO THE E ON FRIDAY WITH PROGRESS OF THE HIGH.
.OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY...
HIGH PRESSURE WILL CONTINUE TO SUPPORT VFR CONDITIONS THROUGH THE
WEEKEND. A COLD FRONT APPROACHING FROM THE WEST WILL BRING SCATTERED
SHOWERS AND THUNDERSTORMS WITH THE POTENTIAL FOR RESTRICTIONS LATE
MONDAY THROUGH TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1150 AM EDT FRI MAY 18 2012
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE FOR QUIET WEATHER AND A WARMING TREND
THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AN UPDATE HAS BEEN ISSUED TO ACCOUNT FOR THE LATEST TRENDS IN TEMPS
AND DEW POINTS.
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 12Z KPIT
SOUNDING INDICATES DEEP SUBSIDENCE AND DRY AIR ALOFT. THUS, CLEAR
SKIES ARE PREVAILING ACROSS THE AREA.
THE 500MB RIDGE WILL BUILD IN FURTHER INTO THE GREAT LAKES REGION
TODAY AND TONIGHT WITH ANTI-CYCLONIC FLOW ALOFT CENTERED ACROSS
NORTHERN OHIO BY 12Z SATURDAY. THIS WILL ALLOW ABUNDANT SUNSHINE TO
CONTINUE ACROSS THE REGION. HIGHS TODAY ARE A FEW DEGREES WARMER
THAN LAMP GUIDANCE, WARMING TO NEAR 80 ACROSS MUCH OF THE AREA.
WITH NEAR CALM WINDS AND CLEAR SKIES TONIGHT, RADIATIONAL COOLING
WILL ALLOW FOR TEMPERATURES TO STEADILY DROP OFF. OVERNIGHT LOWS
WILL RANGE FROM THE MID 40S ACROSS THE I-80 CORRIDOR AND EASTERN
RIDGES TO THE LOWER 50S ACROSS PORTIONS OF EASTERN OHIO AND
NORTH-CENTRAL WV.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
HIGH PRESSURE RIDGE WILL CONTINUE TO DOMINATE THE FORECAST THROUGH
AT LEAST SUNDAY AS SUGGESTED BY MOST GLOBAL MODELS. AS THE RIDGE
CONTINUES TO BUILD AND SLIDE TOWARD THE COAST...850MB TEMPERATURES
ALOFT WILL REACH 16C...WHICH SHOULD HELP TO BRING TEMPERATURES 5
TO 10 DEGREES ABOVE NORMAL SATURDAY AND SUNDAY. THOUGH CURRENT
FORECAST HIGHS ARE SLIGHTLY BELOW MOS GUIDANCE...WHICH LOOKED A
LITTLE TOO HIGH.
MODEL AGREEMENT THEN DIVERGES INTO SUNDAY NIGHT AND MONDAY ON THE
TIMING AND PLACEMENT OF THE MID-UPPER LEVEL CLOSED LOW OVER THE
SOUTHEAST. THERE CONTINUES TO BE A GROUPING BETWEEN THE
NAM/CANADIAN AND GFS/ECMWF. SINCE NOT MUCH HAS CHANGED IN THE
DETERMINISTIC MODELS WITH THE NEW RUNS...OPTED TO CONTINUE THE DRY
FORECAST FOR SUNDAY NIGHT...GRADUALLY BRINGING IN POPS FROM BOTH
THE EAST WITH THE RETROGRADING LOW AND THE WEST WITH THE SLOW
MOVING COLD FRONT BY LATE MONDAY. THIS WAS CLOSEST TO GFS/ECMWF
AND SREF ENSEMBLE MEAN THROUGH THE PERIOD. KEPT TEMPERATURES A FEW
DEGREES ABOVE MOS GUIDANCE AND STILL A FEW DEGREES ABOVE NORMAL
MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
WITH CONTINUED MODEL DISAGREEMENT...MAINTAINED A FORECAST CLOSE TO
HPC GUIDANCE WITH HEAVY EMPHASIS ON THE MOST RECENT GFS RUN WHICH
BRINGS THE COLD FRONT THROUGH THE REGION THE FASTEST MONDAY NIGHT
AND TUESDAY.
A SURFACE RIDGE PROGGED TO BUILD IN FROM THE MIDWEST LATE WEDNESDAY
INTO THURSDAY SHOULD PROVIDE A RETURN TO DRY WEATHER FOR THE MIDDLE
OF THE WEEK.
TEMPERATURES ARE FORECAST TO RANGE FROM 5 TO 10 DEGREES ABOVE NORMAL
THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD AS SURFACE HIGH
PRESSURE SLIDES EASTWARD FROM THE GREAT LAKES AND OVER NEW ENGLAND.
LGT NE SFC WND WL VEER TO THE E ON FRIDAY WITH PROGRESS OF THE HIGH.
.OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY...
HIGH PRESSURE WILL CONTINUE TO SUPPORT VFR CONDITIONS THROUGH THE
WEEKEND. A COLD FRONT APPROACHING FROM THE WEST WILL BRING SCATTERED
SHOWERS AND THUNDERSTORMS WITH THE POTENTIAL FOR RESTRICTIONS LATE
MONDAY THROUGH TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
152 PM EDT FRI MAY 18 2012
.UPDATE...
ISSUED AT 1005 AM EDT FRI MAY 18 2012
INCREASED POPS TO CATEGORICAL AND INCREASED SKY COVER FOR REST OF
MORNING AS BATCH OF SHRA/SCT TSRA MAINLY AFFECT AREAS FM MUNISING TO
NEWBERRY INTO EASTERN UPR MICHIGAN. BASED ON REPORTS SO FAR...EXPECT
RAIN AMOUNTS TO END UP LESS THAN 0.25 INCH MOST AREAS. SKIES HAVE
ALREADY CLEARED OVER WEST AND SOUTHWEST UPR MICHIGAN. 12Z GRB
SOUNDING POINTS TO MAX TEMPS AS WARM AS LOWER 90S. MAY NEED TO RAISE
TEMPS SOME OVER FCST...BUT WILL WAIT FOR TEMP TRENDS NEXT FEW HOURS
BEFORE MAKING SIGNIFICANT ADJUSTMENTS. REST OF FCST ON TRACK FOR
NOW.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 421 AM EDT FRI MAY 18 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG OVER CNTRL
NAMERICA BTWN TROFS ALONG THE W COAST AND OVER QUEBEC. ALTHOUGH NO
REAL STRONG SHRTWV IS NOTICEABLE ROUNDING THE TOP OF THE RDG AND
AIRMASS TO THE S IS QUITE DRY PER 00Z MPX RAOB...A CLUSTER OF
SHRA/TS HAS DEVELOPED ON A WNW-ESE AXIS IN AREA OF VIGOROUS H85
THETA-E ADVCTN UNDER AREA OF UPR DVGC INDICATED BY VARIOUS MODELS
AT NOSE OF NOCTURNAL STRENGTHENING H85 SW LLJ BTWN HI PRES OVER LWR
MI AND LO PRES IN ERN NDAKOTA. SPC ANALYSIS INDICATES MUCAPE 500-
1000 J/KG IN THIS AREA NEAR H85 WARM FNT WITH THE STRONG H85 WARMING
SHARPENING LAPSE RATES. EVEN THOUGH THESE STORMS APPEAR TO BE
ELEVATED...SOME OF THEM HAVE CAUSED WIND GUSTS UP TO 30-40 KTS.
FARTHER TO THE S...THE AIRMASS IN THE WARM SECTOR IS VERY WARM AND
DRY. HI TEMPS OVER SW MN ROSE INTO THE LO 90S YDAY WITH DEWPTS AS LO
AS 35 TO 40 UNDER MOSUNNY SKIES. LLVL MSTR AT OMAHA WAS QUITE A BIT
GREATER AT 00Z THAN JUST TO THE N
MAIN FCST CONCERNS IN THE SHORT TERM ARE SHRA/TS CHCS THRU THIS MRNG
AND THEN FIRE WX THIS AFTN/SAT AS WARM AND DRY AIR TO THE S SURGES
INTO THE UPR LKS.
TODAY...EXPECT LINGERING SHRA/TS OVER THE KEWEENAW/NRN TIER IN THE
MRNG TO DRIFT TO THE NE WITH PASSAGE OF H85 WARM FNT UNDER BLDG UPR
RDG TO THE E OF DEEPENING TROF OVER THE W. STEADY SSW FLOW IN THE
WAKE OF THE WARM FROPA IS FCST TO PUSH H85 TEMPS AS HI AS 18C OVER
THE W HALF. MIXING TO H8 ON NAM FCST SDNGS INDICATES HI TEMPS WL
REACH 85 OVER THE W HALF WITH INCRSG SUNSHINE...BUT LOCATIONS
DOWNSTREAM OF LK MI WL BE COOLER. FORTUNATELY FOR FIRE WX
CONCERNS...MODELS ARE IN GOOD AGREEMENT SHOWING HIER LLVL MSTR
RETURNING INTO THE W HALF THRU THE DAY AS THE FLOW TAPS THE GREATER
MSTR SHOWN ON THE OMAHA RAOB AND THE SW WIND DIMINISHING A BIT WITH
ARRIVAL OF WEAKER PRES FALLS TO THE N. AXIS OF DRIER AIR WL REMAIN
OVER THE E HALF...BUT MODERATION OFF LK MI WL HOLD TEMPS DOWN IN
THAT AREA SOMEWHAT. SFC HEATING WL SUPPORT MIXING OF H95-9 WINDS UP
TO 35 KTS...STRONGEST OVER THE E. SEE THE FIRE WX DISCUSSION FOR
MORE DETAILS ON FIRE WX CONCERNS.
TNGT...CWA WL BE IN WARM SECTOR TNGT WITH UPR RDG OVER THE CNTRL GRT
LKS. STEADY SW FLOW/H925 WIND UP TO 35 KTS UNDER SHARP PRES GRADIENT
BTWN HI PRES RETREATING TO THE E AND LO PRES ADVANCING SLOWLY THRU
THE PLAINS WL LIMIT THE DIURNAL FALL OF TEMP DESPITE A MOCLR
SKY...ESPECIALLY ACRS THE DOWNSLOPE AREAS OF THE W AND NCNTRL AS
REFLECTED IN PREVIOUS FCST.
SAT...UPR MI WL REMAIN UNDER THE STEADY SSW FLOW BTWN HI PRES TO THE
E AND LO PRES TROF/COLD FNT ADVANCING THRU MN. WITH HI AMPLITUDE UPR
RDG OVER THE GRT LKS/NE CONUS...PREFER A SLOWER EWD PROGRESSION FOR
THE TROF AS SHOWN BY THE 00Z CNDN MODEL. SO RESTRICTED ANY POPS TO
FAR WRN LK SUP LATE IN THE DAY. MIXING TO H8-75 YIELDS HI TEMPS
APRCHG 90 OVER THE W HALF AWAY FM THE MODERATING INFLUENCE OF LK MI.
THIS DAYTIME MIXING WL ONCE AGAIN TAP H925 WINDS UP TO 35 KTS.
AXIS OF DRIEST AIR REMAINS OVER THE E...BUT FLOW OFF LK MI WL LIKELY
MODERATE MIXING/IMPACT ON SFC DEWPTS.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 421 AM EDT FRI MAY 18 2012
THE PERIOD STARTS 00Z SUN WITH A 500MB RIDGE AXIS JUST E OF THE CWA.
MORE IMPORTANTLY...TO OUR W WILL BE A 500MB TROUGH FROM NRN SASK TO
THE CENTRAL PLAINS STATES. THERE WILL BE A SHORTWAVE TROUGH PUSHING
THROUGH FAR WRN ONTARIO...WITH A 1002MB SFC LOW BENEATH IT. MODELS
SHOW FAIRLY GOOD AGREEMENT ON POSITION OF THESE FEATURES AND WITH
THE POSITION OF A SFC TROUGH/COLD FRONT JUST W OF THE CWA AT 00Z
SUN.
SAT NIGHT THROUGH MON...MODELS SHOW SAME GENERAL IDEA THAT THE
COLD FRONT WILL CROSS THE CWA...PRODUCING PRECIP ACROSS THE
AREA...BUT DIFFER IN TIMING. THE 00Z/18 GFS CONTINUES TO BE A FAST
OUTLIER WITH FROPA. THE 12Z/17 ECMWF CONTINUES TO BE ON THE SLOWER
SIDE...BUT IS CLOSER TO THE MORE MIDDLE GROUND 00Z/18 NAM AND 00Z/18
GEM MODELS THAN THE GFS IS. THE SLOWER SOLUTION IS ALSO SUPPORTED BY
THE FACT THAT THE SYSTEM WILL BE PUSHING INTO THE UPPER
RIDGE...WHICH TYPICALLY RESULTS IN SLOWER MOVEMENT OF THE SYSTEM.
USED A NAM/GEM/ECMWF MIX FOR THIS PART OF THE FORECAST. THIS RESULTS
IN THE FRONT MOVING INTO WRN UPPER MI AROUND 15Z SUN...THEN MOVING
THE CENTRAL UPPER MI AROUND 00Z MON...AND MOVING TO FAR ERN UPPER BY
AROUND 09Z MON. BULK OF MOISTURE...CLOUDS AND PRECIP WILL BE ALONG
AND BEHIND THIS ANAFRONT...ALLOWING FOR PLENTY OF TIME FOR SFC
HEATING AND DESTABILIZATION SUN OVER CENTRAL AND WESTERN UPPER MI.
HIGHS SUN LOOK TO BE IN THE MID TO UPPER 70S OVER CENTRAL AND PARTS
OF WRN UPPER MI...AND EVEN AS HIGH AS THE MID 80S OVER SOUTH CENTRAL
AND FAR ERN UPPER MI. MODELS SHOW SBCAPE OF 1000-1500J/KG AHEAD OF
TO JUST BEHIND THE COLD FRONT....WITH 0-6KM BULK SHEAR AROUND 30KTS.
CANNOT RULE OUT POSSIBILITY OF AN ISOLATED SEVERE THREAT FROM
CONVECTION SUN AFTERNOON/EVENING...BUT NOT CONFIDENT ENOUGH TO
MENTION SPECIFICALLY IN HWO. I THINK THE BEST CHANCE FOR SEVERE
THUNDERSTORMS WOULD BE OVER SOUTH CENTRAL UPPER MI AS THE FRONT
INTERACTS WITH LAKE MICHIGAN LAKE BREEZE BOUNDARIES. DID UP POPS FOR
THE PERIOD TO INCLUDE SOME LIKELY POPS...WHICH I WAS COMFORTABLE
DOING GIVEN PWATS AT 200 PERCENT OF NORMAL AND SLOW MOVEMENT OF THE
FRONT THROUGH GOOD INSTABILITY.
SFC HIGH PRESSURE MOVES IN BEHIND THE SFC TROUGH...AND MOVES E OF
THE CWA WED AS AN UPPER RIDGE MOVES OVERHEAD. THIS UPPER RIDGE GETS
SHUNTED E AS A LOW PRESSURE SYSTEM MOVES IN THE NRN PLAINS...BUT
THERE IS A LOT OF DISAGREEMENT BETWEEN MODELS ON THE STRENGTH AND
LOCATION OF THIS SYSTEM. MOST OF THE CWA SHOULD STAY DRY TUE THROUGH
THU...WITH A GENERAL WARMING TREND MON THROUGH THU.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 150 PM EDT FRI MAY 18 2012
WARM FRONT IS NORTH OF THE AREA AND ONLY CLOUDS THROUGH SATURDAY
AFTN WILL BE HIGH AND SCATTERED VARIETY. VFR CONDITIONS DOMINATE. SW
WINDS COULD BE GUSTY THIS AFTN AT IWD AND SAW. LATER THIS EVENING
THROUGH DAYBREAK ON SATURDAY...EXPECT MORE LLWS AS DIURNAL MIXING
DIMINISHES SFC WINDS BUT LOW-LVL JET MAX OF 35 TO 40 KT REMAINS OVER
THE AREA. MORE GUSTY SW WINDS EXPECTED ON SATURDAY...ESPECIALLY AT
IWD AND SAW. &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 421 AM EDT FRI MAY 18 2012
WINDS ACROSS LAKE SUPERIOR SHOULD REMAIN BELOW 25KTS THROUGH THE
PERIOD. HIGH PRESSURE ACROSS THE LOWER GREAT LAKES WILL SLOWLY MOVE
TO NEW ENGLAND TODAY INTO SATURDAY. LOW PRESSURE OVER SOUTHERN
SASKATCHEWAN AND THE DAKOTAS WILL PUSH ACROSS THE NORTHERN AND
CENTRAL PLAINS 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.
&&
.FIRE WEATHER...
ISSUED AT 421 AM EDT FRI MAY 18 2012
DRY SPELL THIS SPRING IS LEADING TO ANOTHER ACTIVE PERIOD OF FIRE
WX. FIRE WEATHER WATCHES ARE IN EFFECT FOR ALL OF UPR MI. A
PROLONGED PERIOD OF AT LEAST NEAR CRITICAL FIRE WX CONDITIONS IS ON
TAP FOR THIS AFTERNOON THROUGH SAT AFTERNOON.
AXIS OF STRONGER WINDS/LOWEST H95-85 SPECIFIC HUMIDITY LINES UP OVER
THE E THIS AFTN...BUT SW FLOW OFF LK MI PRESENTS A CHALLENGE AS TO
HOW MUCH COOLING/MOISTENING WILL OCCUR RELATED TO THE LAKE
MODERATION. ALTHOUGH MAX TEMPS OVER THE W WILL BE HIER...GRADUAL
ARRIVAL OF MOISTER AIR WILL TEND TO MITIGATE THE DIURNAL FALL OF RH.
CONSIDERING THE SHOWERS THAT FELL OVER MOST OF THE AREA EARLY THIS
MRNG AND EXPECTED MIN RH IN THE 25-30 PERCENT RANGE...OPTED TO ISSUE
A WILDFIRE POTENTIAL STATEMENT IN LIEU OF A RED FLAG WARNING EVEN
THOUGH DEEP MIXING THIS AFTERNOON WILL TRANSPORT STRONGER WINDS TO
THE SFC AT TIMES.
STEADY S WIND TNGT WL LIMIT DIURNAL FALL OF TEMP...EXACERBATING THE
DRYNESS.
ON SAT...ANOTHER DAY WHERE THE AXIS OF DRIEST AIR WILL BE ACROSS ERN
UPR MI. ALTHOUGH DEEP MIXING THAT WILL TAP STRONGER WINDS OFF THE
SFC WOULD ALSO TEND TO LOWER THE MIN RH...FLOW OFF LAKE MI WILL
MODERATE THE FALL OF RH. EXPECTED MIN RH AND POTENTIAL FOR GUSTY
WINDS AFTER A NIGHT OF LIMITED RH RECOVERY JUSTIFIED MAINTAINING THE
GOING FIRE WX WATCH IN THE AFTERNOON.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR MIZ001>015-084-085.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...JLA
MARINE...TITUS
FIRE WEATHER...KC
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1006 AM EDT FRI MAY 18 2012
.UPDATE...
ISSUED AT 1005 AM EDT FRI MAY 18 2012
INCREASED POPS TO CATEGORICAL AND INCREASED SKY COVER FOR REST OF
MORNING AS BATCH OF SHRA/SCT TSRA MAINLY AFFECT AREAS FM MUNISING TO
NEWBERRY INTO EASTERN UPR MICHIGAN. BASED ON REPORTS SO FAR...EXPECT
RAIN AMOUNTS TO END UP LESS THAN 0.25 INCH MOST AREAS. SKIES HAVE
ALREADY CLEARED OVER WEST AND SOUTHWEST UPR MICHIGAN. 12Z GRB
SOUNDING POINTS TO MAX TEMPS AS WARM AS LOWER 90S. MAY NEED TO RAISE
TEMPS SOME OVER FCST...BUT WILL WAIT FOR TEMP TRENDS NEXT FEW HOURS
BEFORE MAKING SIGNIFICANT ADJUSTMENTS. REST OF FCST ON TRACK FOR
NOW.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 421 AM EDT FRI MAY 18 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG OVER CNTRL
NAMERICA BTWN TROFS ALONG THE W COAST AND OVER QUEBEC. ALTHOUGH NO
REAL STRONG SHRTWV IS NOTICEABLE ROUNDING THE TOP OF THE RDG AND
AIRMASS TO THE S IS QUITE DRY PER 00Z MPX RAOB...A CLUSTER OF
SHRA/TS HAS DEVELOPED ON A WNW-ESE AXIS IN AREA OF VIGOROUS H85
THETA-E ADVCTN UNDER AREA OF UPR DVGC INDICATED BY VARIOUS MODELS
AT NOSE OF NOCTURNAL STRENGTHENING H85 SW LLJ BTWN HI PRES OVER LWR
MI AND LO PRES IN ERN NDAKOTA. SPC ANALYSIS INDICATES MUCAPE 500-
1000 J/KG IN THIS AREA NEAR H85 WARM FNT WITH THE STRONG H85 WARMING
SHARPENING LAPSE RATES. EVEN THOUGH THESE STORMS APPEAR TO BE
ELEVATED...SOME OF THEM HAVE CAUSED WIND GUSTS UP TO 30-40 KTS.
FARTHER TO THE S...THE AIRMASS IN THE WARM SECTOR IS VERY WARM AND
DRY. HI TEMPS OVER SW MN ROSE INTO THE LO 90S YDAY WITH DEWPTS AS LO
AS 35 TO 40 UNDER MOSUNNY SKIES. LLVL MSTR AT OMAHA WAS QUITE A BIT
GREATER AT 00Z THAN JUST TO THE N
MAIN FCST CONCERNS IN THE SHORT TERM ARE SHRA/TS CHCS THRU THIS MRNG
AND THEN FIRE WX THIS AFTN/SAT AS WARM AND DRY AIR TO THE S SURGES
INTO THE UPR LKS.
TODAY...EXPECT LINGERING SHRA/TS OVER THE KEWEENAW/NRN TIER IN THE
MRNG TO DRIFT TO THE NE WITH PASSAGE OF H85 WARM FNT UNDER BLDG UPR
RDG TO THE E OF DEEPENING TROF OVER THE W. STEADY SSW FLOW IN THE
WAKE OF THE WARM FROPA IS FCST TO PUSH H85 TEMPS AS HI AS 18C OVER
THE W HALF. MIXING TO H8 ON NAM FCST SDNGS INDICATES HI TEMPS WL
REACH 85 OVER THE W HALF WITH INCRSG SUNSHINE...BUT LOCATIONS
DOWNSTREAM OF LK MI WL BE COOLER. FORTUNATELY FOR FIRE WX
CONCERNS...MODELS ARE IN GOOD AGREEMENT SHOWING HIER LLVL MSTR
RETURNING INTO THE W HALF THRU THE DAY AS THE FLOW TAPS THE GREATER
MSTR SHOWN ON THE OMAHA RAOB AND THE SW WIND DIMINISHING A BIT WITH
ARRIVAL OF WEAKER PRES FALLS TO THE N. AXIS OF DRIER AIR WL REMAIN
OVER THE E HALF...BUT MODERATION OFF LK MI WL HOLD TEMPS DOWN IN
THAT AREA SOMEWHAT. SFC HEATING WL SUPPORT MIXING OF H95-9 WINDS UP
TO 35 KTS...STRONGEST OVER THE E. SEE THE FIRE WX DISCUSSION FOR
MORE DETAILS ON FIRE WX CONCERNS.
TNGT...CWA WL BE IN WARM SECTOR TNGT WITH UPR RDG OVER THE CNTRL GRT
LKS. STEADY SW FLOW/H925 WIND UP TO 35 KTS UNDER SHARP PRES GRADIENT
BTWN HI PRES RETREATING TO THE E AND LO PRES ADVANCING SLOWLY THRU
THE PLAINS WL LIMIT THE DIURNAL FALL OF TEMP DESPITE A MOCLR
SKY...ESPECIALLY ACRS THE DOWNSLOPE AREAS OF THE W AND NCNTRL AS
REFLECTED IN PREVIOUS FCST.
SAT...UPR MI WL REMAIN UNDER THE STEADY SSW FLOW BTWN HI PRES TO THE
E AND LO PRES TROF/COLD FNT ADVANCING THRU MN. WITH HI AMPLITUDE UPR
RDG OVER THE GRT LKS/NE CONUS...PREFER A SLOWER EWD PROGRESSION FOR
THE TROF AS SHOWN BY THE 00Z CNDN MODEL. SO RESTRICTED ANY POPS TO
FAR WRN LK SUP LATE IN THE DAY. MIXING TO H8-75 YIELDS HI TEMPS
APRCHG 90 OVER THE W HALF AWAY FM THE MODERATING INFLUENCE OF LK MI.
THIS DAYTIME MIXING WL ONCE AGAIN TAP H925 WINDS UP TO 35 KTS.
AXIS OF DRIEST AIR REMAINS OVER THE E...BUT FLOW OFF LK MI WL LIKELY
MODERATE MIXING/IMPACT ON SFC DEWPTS.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 421 AM EDT FRI MAY 18 2012
THE PERIOD STARTS 00Z SUN WITH A 500MB RIDGE AXIS JUST E OF THE CWA.
MORE IMPORTANTLY...TO OUR W WILL BE A 500MB TROUGH FROM NRN SASK TO
THE CENTRAL PLAINS STATES. THERE WILL BE A SHORTWAVE TROUGH PUSHING
THROUGH FAR WRN ONTARIO...WITH A 1002MB SFC LOW BENEATH IT. MODELS
SHOW FAIRLY GOOD AGREEMENT ON POSITION OF THESE FEATURES AND WITH
THE POSITION OF A SFC TROUGH/COLD FRONT JUST W OF THE CWA AT 00Z
SUN.
SAT NIGHT THROUGH MON...MODELS SHOW SAME GENERAL IDEA THAT THE
COLD FRONT WILL CROSS THE CWA...PRODUCING PRECIP ACROSS THE
AREA...BUT DIFFER IN TIMING. THE 00Z/18 GFS CONTINUES TO BE A FAST
OUTLIER WITH FROPA. THE 12Z/17 ECMWF CONTINUES TO BE ON THE SLOWER
SIDE...BUT IS CLOSER TO THE MORE MIDDLE GROUND 00Z/18 NAM AND 00Z/18
GEM MODELS THAN THE GFS IS. THE SLOWER SOLUTION IS ALSO SUPPORTED BY
THE FACT THAT THE SYSTEM WILL BE PUSHING INTO THE UPPER
RIDGE...WHICH TYPICALLY RESULTS IN SLOWER MOVEMENT OF THE SYSTEM.
USED A NAM/GEM/ECMWF MIX FOR THIS PART OF THE FORECAST. THIS RESULTS
IN THE FRONT MOVING INTO WRN UPPER MI AROUND 15Z SUN...THEN MOVING
THE CENTRAL UPPER MI AROUND 00Z MON...AND MOVING TO FAR ERN UPPER BY
AROUND 09Z MON. BULK OF MOISTURE...CLOUDS AND PRECIP WILL BE ALONG
AND BEHIND THIS ANAFRONT...ALLOWING FOR PLENTY OF TIME FOR SFC
HEATING AND DESTABILIZATION SUN OVER CENTRAL AND WESTERN UPPER MI.
HIGHS SUN LOOK TO BE IN THE MID TO UPPER 70S OVER CENTRAL AND PARTS
OF WRN UPPER MI...AND EVEN AS HIGH AS THE MID 80S OVER SOUTH CENTRAL
AND FAR ERN UPPER MI. MODELS SHOW SBCAPE OF 1000-1500J/KG AHEAD OF
TO JUST BEHIND THE COLD FRONT....WITH 0-6KM BULK SHEAR AROUND 30KTS.
CANNOT RULE OUT POSSIBILITY OF AN ISOLATED SEVERE THREAT FROM
CONVECTION SUN AFTERNOON/EVENING...BUT NOT CONFIDENT ENOUGH TO
MENTION SPECIFICALLY IN HWO. I THINK THE BEST CHANCE FOR SEVERE
THUNDERSTORMS WOULD BE OVER SOUTH CENTRAL UPPER MI AS THE FRONT
INTERACTS WITH LAKE MICHIGAN LAKE BREEZE BOUNDARIES. DID UP POPS FOR
THE PERIOD TO INCLUDE SOME LIKELY POPS...WHICH I WAS COMFORTABLE
DOING GIVEN PWATS AT 200 PERCENT OF NORMAL AND SLOW MOVEMENT OF THE
FRONT THROUGH GOOD INSTABILITY.
SFC HIGH PRESSURE MOVES IN BEHIND THE SFC TROUGH...AND MOVES E OF
THE CWA WED AS AN UPPER RIDGE MOVES OVERHEAD. THIS UPPER RIDGE GETS
SHUNTED E AS A LOW PRESSURE SYSTEM MOVES IN THE NRN PLAINS...BUT
THERE IS A LOT OF DISAGREEMENT BETWEEN MODELS ON THE STRENGTH AND
LOCATION OF THIS SYSTEM. MOST OF THE CWA SHOULD STAY DRY TUE THROUGH
THU...WITH A GENERAL WARMING TREND MON THROUGH THU.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 726 AM EDT FRI MAY 18 2012
A WARM FRONT MAKING ITS WAY ACROSS THE REGION THIS MORNING WILL
CONTINUE TO MOVE NORTH THROUGH THE MORNING...TAKING THE RAIN OVER
THE AREA WITH IT. LLWS WILL END AROUND SUNRISE TODAY. GUSTY SW WINDS
AOA 25 KT WILL DEVELOP TODAY AS MID CLOUDS SCATTER OUT. LOOK FOR
LLWS AGAIN BY FRI EVENING AS DIURNAL MIXING DIMINISHES SFC WIND
SOMEWHAT BUT LOW-LVL JET MAX OF 35 TO 40 KT REMAINS OVER THE AREA.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 421 AM EDT FRI MAY 18 2012
WINDS ACROSS LAKE SUPERIOR SHOULD REMAIN BELOW 25KTS THROUGH THE
PERIOD. HIGH PRESSURE ACROSS THE LOWER GREAT LAKES WILL SLOWLY MOVE
TO NEW ENGLAND TODAY INTO SATURDAY. LOW PRESSURE OVER SOUTHERN
SASKATCHEWAN AND THE DAKOTAS WILL PUSH ACROSS THE NORTHERN AND
CENTRAL PLAINS 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.
&&
.FIRE WEATHER...
ISSUED AT 421 AM EDT FRI MAY 18 2012
DRY SPELL THIS SPRING IS LEADING TO ANOTHER ACTIVE PERIOD OF FIRE
WX. FIRE WEATHER WATCHES ARE IN EFFECT FOR ALL OF UPR MI. A
PROLONGED PERIOD OF AT LEAST NEAR CRITICAL FIRE WX CONDITIONS IS ON
TAP FOR THIS AFTERNOON THROUGH SAT AFTERNOON.
AXIS OF STRONGER WINDS/LOWEST H95-85 SPECIFIC HUMIDITY LINES UP OVER
THE E THIS AFTN...BUT SW FLOW OFF LK MI PRESENTS A CHALLENGE AS TO
HOW MUCH COOLING/MOISTENING WILL OCCUR RELATED TO THE LAKE
MODERATION. ALTHOUGH MAX TEMPS OVER THE W WILL BE HIER...GRADUAL
ARRIVAL OF MOISTER AIR WILL TEND TO MITIGATE THE DIURNAL FALL OF RH.
CONSIDERING THE SHOWERS THAT FELL OVER MOST OF THE AREA EARLY THIS
MRNG AND EXPECTED MIN RH IN THE 25-30 PERCENT RANGE...OPTED TO ISSUE
A WILDFIRE POTENTIAL STATEMENT IN LIEU OF A RED FLAG WARNING EVEN
THOUGH DEEP MIXING THIS AFTERNOON WILL TRANSPORT STRONGER WINDS TO
THE SFC AT TIMES.
STEADY S WIND TNGT WL LIMIT DIURNAL FALL OF TEMP...EXACERBATING THE
DRYNESS.
ON SAT...ANOTHER DAY WHERE THE AXIS OF DRIEST AIR WILL BE ACROSS ERN
UPR MI. ALTHOUGH DEEP MIXING THAT WILL TAP STRONGER WINDS OFF THE
SFC WOULD ALSO TEND TO LOWER THE MIN RH...FLOW OFF LAKE MI WILL
MODERATE THE FALL OF RH. EXPECTED MIN RH AND POTENTIAL FOR GUSTY
WINDS AFTER A NIGHT OF LIMITED RH RECOVERY JUSTIFIED MAINTAINING THE
GOING FIRE WX WATCH IN THE AFTERNOON.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR MIZ001>015-084-085.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...TITUS
MARINE...TITUS
FIRE WEATHER...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
727 AM EDT FRI MAY 18 2012
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 421 AM EDT FRI MAY 18 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG OVER CNTRL
NAMERICA BTWN TROFS ALONG THE W COAST AND OVER QUEBEC. ALTHOUGH NO
REAL STRONG SHRTWV IS NOTICEABLE ROUNDING THE TOP OF THE RDG AND
AIRMASS TO THE S IS QUITE DRY PER 00Z MPX RAOB...A CLUSTER OF
SHRA/TS HAS DEVELOPED ON A WNW-ESE AXIS IN AREA OF VIGOROUS H85
THETA-E ADVCTN UNDER AREA OF UPR DVGC INDICATED BY VARIOUS MODELS
AT NOSE OF NOCTURNAL STRENGTHENING H85 SW LLJ BTWN HI PRES OVER LWR
MI AND LO PRES IN ERN NDAKOTA. SPC ANALYSIS INDICATES MUCAPE 500-
1000 J/KG IN THIS AREA NEAR H85 WARM FNT WITH THE STRONG H85 WARMING
SHARPENING LAPSE RATES. EVEN THOUGH THESE STORMS APPEAR TO BE
ELEVATED...SOME OF THEM HAVE CAUSED WIND GUSTS UP TO 30-40 KTS.
FARTHER TO THE S...THE AIRMASS IN THE WARM SECTOR IS VERY WARM AND
DRY. HI TEMPS OVER SW MN ROSE INTO THE LO 90S YDAY WITH DEWPTS AS LO
AS 35 TO 40 UNDER MOSUNNY SKIES. LLVL MSTR AT OMAHA WAS QUITE A BIT
GREATER AT 00Z THAN JUST TO THE N
MAIN FCST CONCERNS IN THE SHORT TERM ARE SHRA/TS CHCS THRU THIS MRNG
AND THEN FIRE WX THIS AFTN/SAT AS WARM AND DRY AIR TO THE S SURGES
INTO THE UPR LKS.
TODAY...EXPECT LINGERING SHRA/TS OVER THE KEWEENAW/NRN TIER IN THE
MRNG TO DRIFT TO THE NE WITH PASSAGE OF H85 WARM FNT UNDER BLDG UPR
RDG TO THE E OF DEEPENING TROF OVER THE W. STEADY SSW FLOW IN THE
WAKE OF THE WARM FROPA IS FCST TO PUSH H85 TEMPS AS HI AS 18C OVER
THE W HALF. MIXING TO H8 ON NAM FCST SDNGS INDICATES HI TEMPS WL
REACH 85 OVER THE W HALF WITH INCRSG SUNSHINE...BUT LOCATIONS
DOWNSTREAM OF LK MI WL BE COOLER. FORTUNATELY FOR FIRE WX
CONCERNS...MODELS ARE IN GOOD AGREEMENT SHOWING HIER LLVL MSTR
RETURNING INTO THE W HALF THRU THE DAY AS THE FLOW TAPS THE GREATER
MSTR SHOWN ON THE OMAHA RAOB AND THE SW WIND DIMINISHING A BIT WITH
ARRIVAL OF WEAKER PRES FALLS TO THE N. AXIS OF DRIER AIR WL REMAIN
OVER THE E HALF...BUT MODERATION OFF LK MI WL HOLD TEMPS DOWN IN
THAT AREA SOMEWHAT. SFC HEATING WL SUPPORT MIXING OF H95-9 WINDS UP
TO 35 KTS...STRONGEST OVER THE E. SEE THE FIRE WX DISCUSSION FOR
MORE DETAILS ON FIRE WX CONCERNS.
TNGT...CWA WL BE IN WARM SECTOR TNGT WITH UPR RDG OVER THE CNTRL GRT
LKS. STEADY SW FLOW/H925 WIND UP TO 35 KTS UNDER SHARP PRES GRADIENT
BTWN HI PRES RETREATING TO THE E AND LO PRES ADVANCING SLOWLY THRU
THE PLAINS WL LIMIT THE DIURNAL FALL OF TEMP DESPITE A MOCLR
SKY...ESPECIALLY ACRS THE DOWNSLOPE AREAS OF THE W AND NCNTRL AS
REFLECTED IN PREVIOUS FCST.
SAT...UPR MI WL REMAIN UNDER THE STEADY SSW FLOW BTWN HI PRES TO THE
E AND LO PRES TROF/COLD FNT ADVANCING THRU MN. WITH HI AMPLITUDE UPR
RDG OVER THE GRT LKS/NE CONUS...PREFER A SLOWER EWD PROGRESSION FOR
THE TROF AS SHOWN BY THE 00Z CNDN MODEL. SO RESTRICTED ANY POPS TO
FAR WRN LK SUP LATE IN THE DAY. MIXING TO H8-75 YIELDS HI TEMPS
APRCHG 90 OVER THE W HALF AWAY FM THE MODERATING INFLUENCE OF LK MI.
THIS DAYTIME MIXING WL ONCE AGAIN TAP H925 WINDS UP TO 35 KTS.
AXIS OF DRIEST AIR REMAINS OVER THE E...BUT FLOW OFF LK MI WL LIKELY
MODERATE MIXING/IMPACT ON SFC DEWPTS.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 421 AM EDT FRI MAY 18 2012
THE PERIOD STARTS 00Z SUN WITH A 500MB RIDGE AXIS JUST E OF THE CWA.
MORE IMPORTANTLY...TO OUR W WILL BE A 500MB TROUGH FROM NRN SASK TO
THE CENTRAL PLAINS STATES. THERE WILL BE A SHORTWAVE TROUGH PUSHING
THROUGH FAR WRN ONTARIO...WITH A 1002MB SFC LOW BENEATH IT. MODELS
SHOW FAIRLY GOOD AGREEMENT ON POSITION OF THESE FEATURES AND WITH
THE POSITION OF A SFC TROUGH/COLD FRONT JUST W OF THE CWA AT 00Z
SUN.
SAT NIGHT THROUGH MON...MODELS SHOW SAME GENERAL IDEA THAT THE
COLD FRONT WILL CROSS THE CWA...PRODUCING PRECIP ACROSS THE
AREA...BUT DIFFER IN TIMING. THE 00Z/18 GFS CONTINUES TO BE A FAST
OUTLIER WITH FROPA. THE 12Z/17 ECMWF CONTINUES TO BE ON THE SLOWER
SIDE...BUT IS CLOSER TO THE MORE MIDDLE GROUND 00Z/18 NAM AND 00Z/18
GEM MODELS THAN THE GFS IS. THE SLOWER SOLUTION IS ALSO SUPPORTED BY
THE FACT THAT THE SYSTEM WILL BE PUSHING INTO THE UPPER
RIDGE...WHICH TYPICALLY RESULTS IN SLOWER MOVEMENT OF THE SYSTEM.
USED A NAM/GEM/ECMWF MIX FOR THIS PART OF THE FORECAST. THIS RESULTS
IN THE FRONT MOVING INTO WRN UPPER MI AROUND 15Z SUN...THEN MOVING
THE CENTRAL UPPER MI AROUND 00Z MON...AND MOVING TO FAR ERN UPPER BY
AROUND 09Z MON. BULK OF MOISTURE...CLOUDS AND PRECIP WILL BE ALONG
AND BEHIND THIS ANAFRONT...ALLOWING FOR PLENTY OF TIME FOR SFC
HEATING AND DESTABILIZATION SUN OVER CENTRAL AND WESTERN UPPER MI.
HIGHS SUN LOOK TO BE IN THE MID TO UPPER 70S OVER CENTRAL AND PARTS
OF WRN UPPER MI...AND EVEN AS HIGH AS THE MID 80S OVER SOUTH CENTRAL
AND FAR ERN UPPER MI. MODELS SHOW SBCAPE OF 1000-1500J/KG AHEAD OF
TO JUST BEHIND THE COLD FRONT....WITH 0-6KM BULK SHEAR AROUND 30KTS.
CANNOT RULE OUT POSSIBILITY OF AN ISOLATED SEVERE THREAT FROM
CONVECTION SUN AFTERNOON/EVENING...BUT NOT CONFIDENT ENOUGH TO
MENTION SPECIFICALLY IN HWO. I THINK THE BEST CHANCE FOR SEVERE
THUNDERSTORMS WOULD BE OVER SOUTH CENTRAL UPPER MI AS THE FRONT
INTERACTS WITH LAKE MICHIGAN LAKE BREEZE BOUNDARIES. DID UP POPS FOR
THE PERIOD TO INCLUDE SOME LIKELY POPS...WHICH I WAS COMFORTABLE
DOING GIVEN PWATS AT 200 PERCENT OF NORMAL AND SLOW MOVEMENT OF THE
FRONT THROUGH GOOD INSTABILITY.
SFC HIGH PRESSURE MOVES IN BEHIND THE SFC TROUGH...AND MOVES E OF
THE CWA WED AS AN UPPER RIDGE MOVES OVERHEAD. THIS UPPER RIDGE GETS
SHUNTED E AS A LOW PRESSURE SYSTEM MOVES IN THE NRN PLAINS...BUT
THERE IS A LOT OF DISAGREEMENT BETWEEN MODELS ON THE STRENGTH AND
LOCATION OF THIS SYSTEM. MOST OF THE CWA SHOULD STAY DRY TUE THROUGH
THU...WITH A GENERAL WARMING TREND MON THROUGH THU.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 726 AM EDT FRI MAY 18 2012
A WARM FRONT MAKING ITS WAY ACROSS THE REGION THIS MORNING WILL
CONTINUE TO MOVE NORTH THROUGH THE MORNING...TAKING THE RAIN OVER
THE AREA WITH IT. LLWS WILL END AROUND SUNRISE TODAY. GUSTY SW WINDS
AOA 25 KT WILL DEVELOP TODAY AS MID CLOUDS SCATTER OUT. LOOK FOR
LLWS AGAIN BY FRI EVENING AS DIURNAL MIXING DIMINISHES SFC WIND
SOMEWHAT BUT LOW-LVL JET MAX OF 35 TO 40 KT REMAINS OVER THE AREA.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 421 AM EDT FRI MAY 18 2012
WINDS ACROSS LAKE SUPERIOR SHOULD REMAIN BELOW 25KTS THROUGH THE
PERIOD. HIGH PRESSURE ACROSS THE LOWER GREAT LAKES WILL SLOWLY MOVE
TO NEW ENGLAND TODAY INTO SATURDAY. LOW PRESSURE OVER SOUTHERN
SASKATCHEWAN AND THE DAKOTAS WILL PUSH ACROSS THE NORTHERN AND
CENTRAL PLAINS 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.
&&
.FIRE WEATHER...
ISSUED AT 421 AM EDT FRI MAY 18 2012
DRY SPELL THIS SPRING IS LEADING TO ANOTHER ACTIVE PERIOD OF FIRE
WX. FIRE WEATHER WATCHES ARE IN EFFECT FOR ALL OF UPR MI. A
PROLONGED PERIOD OF AT LEAST NEAR CRITICAL FIRE WX CONDITIONS IS ON
TAP FOR THIS AFTERNOON THROUGH SAT AFTERNOON.
AXIS OF STRONGER WINDS/LOWEST H95-85 SPECIFIC HUMIDITY LINES UP OVER
THE E THIS AFTN...BUT SW FLOW OFF LK MI PRESENTS A CHALLENGE AS TO
HOW MUCH COOLING/MOISTENING WILL OCCUR RELATED TO THE LAKE
MODERATION. ALTHOUGH MAX TEMPS OVER THE W WILL BE HIER...GRADUAL
ARRIVAL OF MOISTER AIR WILL TEND TO MITIGATE THE DIURNAL FALL OF RH.
CONSIDERING THE SHOWERS THAT FELL OVER MOST OF THE AREA EARLY THIS
MRNG AND EXPECTED MIN RH IN THE 25-30 PERCENT RANGE...OPTED TO ISSUE
A WILDFIRE POTENTIAL STATEMENT IN LIEU OF A RED FLAG WARNING EVEN
THOUGH DEEP MIXING THIS AFTERNOON WILL TRANSPORT STRONGER WINDS TO
THE SFC AT TIMES.
STEADY S WIND TNGT WL LIMIT DIURNAL FALL OF TEMP...EXACERBATING THE
DRYNESS.
ON SAT...ANOTHER DAY WHERE THE AXIS OF DRIEST AIR WILL BE ACROSS ERN
UPR MI. ALTHOUGH DEEP MIXING THAT WILL TAP STRONGER WINDS OFF THE
SFC WOULD ALSO TEND TO LOWER THE MIN RH...FLOW OFF LAKE MI WILL
MODERATE THE FALL OF RH. EXPECTED MIN RH AND POTENTIAL FOR GUSTY
WINDS AFTER A NIGHT OF LIMITED RH RECOVERY JUSTIFIED MAINTAINING THE
GOING FIRE WX WATCH IN THE AFTERNOON.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR MIZ001>015-084-085.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...TITUS
MARINE...TITUS
FIRE WEATHER...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
422 AM EDT FRI MAY 18 2012
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 421 AM EDT FRI MAY 18 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG OVER CNTRL
NAMERICA BTWN TROFS ALONG THE W COAST AND OVER QUEBEC. ALTHOUGH NO
REAL STRONG SHRTWV IS NOTICEABLE ROUNDING THE TOP OF THE RDG AND
AIRMASS TO THE S IS QUITE DRY PER 00Z MPX RAOB...A CLUSTER OF
SHRA/TS HAS DEVELOPED ON A WNW-ESE AXIS IN AREA OF VIGOROUS H85
THETA-E ADVCTN UNDER AREA OF UPR DVGC INDICATED BY VARIOUS MODELS
AT NOSE OF NOCTURNAL STRENGTHENING H85 SW LLJ BTWN HI PRES OVER LWR
MI AND LO PRES IN ERN NDAKOTA. SPC ANALYSIS INDICATES MUCAPE 500-
1000 J/KG IN THIS AREA NEAR H85 WARM FNT WITH THE STRONG H85 WARMING
SHARPENING LAPSE RATES. EVEN THOUGH THESE STORMS APPEAR TO BE
ELEVATED...SOME OF THEM HAVE CAUSED WIND GUSTS UP TO 30-40 KTS.
FARTHER TO THE S...THE AIRMASS IN THE WARM SECTOR IS VERY WARM AND
DRY. HI TEMPS OVER SW MN ROSE INTO THE LO 90S YDAY WITH DEWPTS AS LO
AS 35 TO 40 UNDER MOSUNNY SKIES. LLVL MSTR AT OMAHA WAS QUITE A BIT
GREATER AT 00Z THAN JUST TO THE N
MAIN FCST CONCERNS IN THE SHORT TERM ARE SHRA/TS CHCS THRU THIS MRNG
AND THEN FIRE WX THIS AFTN/SAT AS WARM AND DRY AIR TO THE S SURGES
INTO THE UPR LKS.
TODAY...EXPECT LINGERING SHRA/TS OVER THE KEWEENAW/NRN TIER IN THE
MRNG TO DRIFT TO THE NE WITH PASSAGE OF H85 WARM FNT UNDER BLDG UPR
RDG TO THE E OF DEEPENING TROF OVER THE W. STEADY SSW FLOW IN THE
WAKE OF THE WARM FROPA IS FCST TO PUSH H85 TEMPS AS HI AS 18C OVER
THE W HALF. MIXING TO H8 ON NAM FCST SDNGS INDICATES HI TEMPS WL
REACH 85 OVER THE W HALF WITH INCRSG SUNSHINE...BUT LOCATIONS
DOWNSTREAM OF LK MI WL BE COOLER. FORTUNATELY FOR FIRE WX
CONCERNS...MODELS ARE IN GOOD AGREEMENT SHOWING HIER LLVL MSTR
RETURNING INTO THE W HALF THRU THE DAY AS THE FLOW TAPS THE GREATER
MSTR SHOWN ON THE OMAHA RAOB AND THE SW WIND DIMINISHING A BIT WITH
ARRIVAL OF WEAKER PRES FALLS TO THE N. AXIS OF DRIER AIR WL REMAIN
OVER THE E HALF...BUT MODERATION OFF LK MI WL HOLD TEMPS DOWN IN
THAT AREA SOMEWHAT. SFC HEATING WL SUPPORT MIXING OF H95-9 WINDS UP
TO 35 KTS...STRONGEST OVER THE E. SEE THE FIRE WX DISCUSSION FOR
MORE DETAILS ON FIRE WX CONCERNS.
TNGT...CWA WL BE IN WARM SECTOR TNGT WITH UPR RDG OVER THE CNTRL GRT
LKS. STEADY SW FLOW/H925 WIND UP TO 35 KTS UNDER SHARP PRES GRADIENT
BTWN HI PRES RETREATING TO THE E AND LO PRES ADVANCING SLOWLY THRU
THE PLAINS WL LIMIT THE DIURNAL FALL OF TEMP DESPITE A MOCLR
SKY...ESPECIALLY ACRS THE DOWNSLOPE AREAS OF THE W AND NCNTRL AS
REFLECTED IN PREVIOUS FCST.
SAT...UPR MI WL REMAIN UNDER THE STEADY SSW FLOW BTWN HI PRES TO THE
E AND LO PRES TROF/COLD FNT ADVANCING THRU MN. WITH HI AMPLITUDE UPR
RDG OVER THE GRT LKS/NE CONUS...PREFER A SLOWER EWD PROGRESSION FOR
THE TROF AS SHOWN BY THE 00Z CNDN MODEL. SO RESTRICTED ANY POPS TO
FAR WRN LK SUP LATE IN THE DAY. MIXING TO H8-75 YIELDS HI TEMPS
APRCHG 90 OVER THE W HALF AWAY FM THE MODERATING INFLUENCE OF LK MI.
THIS DAYTIME MIXING WL ONCE AGAIN TAP H925 WINDS UP TO 35 KTS.
AXIS OF DRIEST AIR REMAINS OVER THE E...BUT FLOW OFF LK MI WL LIKELY
MODERATE MIXING/IMPACT ON SFC DEWPTS.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 421 AM EDT FRI MAY 18 2012
THE PERIOD STARTS 00Z SUN WITH A 500MB RIDGE AXIS JUST E OF THE CWA.
MORE IMPORTANTLY...TO OUR W WILL BE A 500MB TROUGH FROM NRN SASK TO
THE CENTRAL PLAINS STATES. THERE WILL BE A SHORTWAVE TROUGH PUSHING
THROUGH FAR WRN ONTARIO...WITH A 1002MB SFC LOW BENEATH IT. MODELS
SHOW FAIRLY GOOD AGREEMENT ON POSITION OF THESE FEATURES AND WITH
THE POSITION OF A SFC TROUGH/COLD FRONT JUST W OF THE CWA AT 00Z
SUN.
SAT NIGHT THROUGH MON...MODELS SHOW SAME GENERAL IDEA THAT THE
COLD FRONT WILL CROSS THE CWA...PRODUCING PRECIP ACROSS THE
AREA...BUT DIFFER IN TIMING. THE 00Z/18 GFS CONTINUES TO BE A FAST
OUTLIER WITH FROPA. THE 12Z/17 ECMWF CONTINUES TO BE ON THE SLOWER
SIDE...BUT IS CLOSER TO THE MORE MIDDLE GROUND 00Z/18 NAM AND 00Z/18
GEM MODELS THAN THE GFS IS. THE SLOWER SOLUTION IS ALSO SUPPORTED BY
THE FACT THAT THE SYSTEM WILL BE PUSHING INTO THE UPPER
RIDGE...WHICH TYPICALLY RESULTS IN SLOWER MOVEMENT OF THE SYSTEM.
USED A NAM/GEM/ECMWF MIX FOR THIS PART OF THE FORECAST. THIS RESULTS
IN THE FRONT MOVING INTO WRN UPPER MI AROUND 15Z SUN...THEN MOVING
THE CENTRAL UPPER MI AROUND 00Z MON...AND MOVING TO FAR ERN UPPER BY
AROUND 09Z MON. BULK OF MOISTURE...CLOUDS AND PRECIP WILL BE ALONG
AND BEHIND THIS ANAFRONT...ALLOWING FOR PLENTY OF TIME FOR SFC
HEATING AND DESTABILIZATION SUN OVER CENTRAL AND WESTERN UPPER MI.
HIGHS SUN LOOK TO BE IN THE MID TO UPPER 70S OVER CENTRAL AND PARTS
OF WRN UPPER MI...AND EVEN AS HIGH AS THE MID 80S OVER SOUTH CENTRAL
AND FAR ERN UPPER MI. MODELS SHOW SBCAPE OF 1000-1500J/KG AHEAD OF
TO JUST BEHIND THE COLD FRONT....WITH 0-6KM BULK SHEAR AROUND 30KTS.
CANNOT RULE OUT POSSIBILITY OF AN ISOLATED SEVERE THREAT FROM
CONVECTION SUN AFTERNOON/EVENING...BUT NOT CONFIDENT ENOUGH TO
MENTION SPECIFICALLY IN HWO. I THINK THE BEST CHANCE FOR SEVERE
THUNDERSTORMS WOULD BE OVER SOUTH CENTRAL UPPER MI AS THE FRONT
INTERACTS WITH LAKE MICHIGAN LAKE BREEZE BOUNDARIES. DID UP POPS FOR
THE PERIOD TO INCLUDE SOME LIKELY POPS...WHICH I WAS COMFORTABLE
DOING GIVEN PWATS AT 200 PERCENT OF NORMAL AND SLOW MOVEMENT OF THE
FRONT THROUGH GOOD INSTABILITY.
SFC HIGH PRESSURE MOVES IN BEHIND THE SFC TROUGH...AND MOVES E OF
THE CWA WED AS AN UPPER RIDGE MOVES OVERHEAD. THIS UPPER RIDGE GETS
SHUNTED E AS A LOW PRESSURE SYSTEM MOVES IN THE NRN PLAINS...BUT
THERE IS A LOT OF DISAGREEMENT BETWEEN MODELS ON THE STRENGTH AND
LOCATION OF THIS SYSTEM. MOST OF THE CWA SHOULD STAY DRY TUE THROUGH
THU...WITH A GENERAL WARMING TREND MON THROUGH THU.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 138 AM EDT FRI MAY 18 2012
A LINE OF CONVECTION FORMING NORTH OF A WARM FRONT OVER CNTRL MN IS
BRUSHING FAR WRN UPR MI WITH SHRA AND POSSIBLE ISOLD TSRA. AS THIS
WARM FRONT LIFTS NORTH ACROSS THE AREA TONIGHT SO WILL THE LINE OF
CONVECTION LIFT NORTH ACROSS THE WRN CWA. ALTHOUGH THE CONVECTION IS
LIKELY TO WEAKEN SLOWLY...OPTED TO INCLUDE MENTION OF TS AT CMX FROM
08Z-11Z. 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 AOA 25 KT
WILL DEVELOP FRIDAY AS MID CLOUDS SCATTER OUT. GIVEN THE DRY AIR OVR
THE REGION...EVEN IF SHRA/TSRA OCCUR...EXPECT VFR CONDITIONS. LOOK
FOR LLWS AGAIN BY FRI EVENING AS DIURNAL MIXING DIMINISHES SFC WIND
SOMEWHAT BUT LOW-LVL JET MAX OF 35 TO 40 KT REMAINS OVER THE AREA.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 421 AM EDT FRI MAY 18 2012
WINDS ACROSS LAKE SUPERIOR SHOULD REMAIN BELOW 25KTS THROUGH THE
PERIOD. HIGH PRESSURE ACROSS THE LOWER GREAT LAKES WILL SLOWLY MOVE
TO NEW ENGLAND TODAY INTO SATURDAY. LOW PRESSURE OVER SOUTHERN
SASKATCHEWAN AND THE DAKOTAS WILL PUSH ACROSS THE NORTHERN AND
CENTRAL PLAINS 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.
&&
.FIRE WEATHER...
ISSUED AT 421 AM EDT FRI MAY 18 2012
DRY SPELL THIS SPRING IS LEADING TO ANOTHER ACTIVE PERIOD OF FIRE
WX. FIRE WEATHER WATCHES ARE IN EFFECT FOR ALL OF UPR MI. A
PROLONGED PERIOD OF AT LEAST NEAR CRITICAL FIRE WX CONDITIONS IS ON
TAP FOR THIS AFTERNOON THROUGH SAT AFTERNOON.
AXIS OF STRONGER WINDS/LOWEST H95-85 SPECIFIC HUMIDITY LINES UP OVER
THE E THIS AFTN...BUT SW FLOW OFF LK MI PRESENTS A CHALLENGE AS TO
HOW MUCH COOLING/MOISTENING WILL OCCUR RELATED TO THE LAKE
MODERATION. ALTHOUGH MAX TEMPS OVER THE W WILL BE HIER...GRADUAL
ARRIVAL OF MOISTER AIR WILL TEND TO MITIGATE THE DIURNAL FALL OF RH.
CONSIDERING THE SHOWERS THAT FELL OVER MOST OF THE AREA EARLY THIS
MRNG AND EXPECTED MIN RH IN THE 25-30 PERCENT RANGE...OPTED TO ISSUE
A WILDFIRE POTENTIAL STATEMENT IN LIEU OF A RED FLAG WARNING EVEN
THOUGH DEEP MIXING THIS AFTERNOON WILL TRANSPORT STRONGER WINDS TO
THE SFC AT TIMES.
STEADY S WIND TNGT WL LIMIT DIURNAL FALL OF TEMP...EXACERBATING THE
DRYNESS.
ON SAT...ANOTHER DAY WHERE THE AXIS OF DRIEST AIR WILL BE ACROSS ERN
UPR MI. ALTHOUGH DEEP MIXING THAT WILL TAP STRONGER WINDS OFF THE
SFC WOULD ALSO TEND TO LOWER THE MIN RH...FLOW OFF LAKE MI WILL
MODERATE THE FALL OF RH. EXPECTED MIN RH AND POTENTIAL FOR GUSTY
WINDS AFTER A NIGHT OF LIMITED RH RECOVERY JUSTIFIED MAINTAINING THE
GOING FIRE WX WATCH IN THE AFTERNOON.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR MIZ001>015-084-085.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...VOSS/KC
MARINE...TITUS
FIRE WEATHER...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
414 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.../18Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED THROUGH MUCH OF THE PERIOD...WITH PERHAPS
SOME MVFR CONDITIONS DEVELOPING OVER WESTERN AREAS AFTER 12Z SAT.
STRONG SOUTH WINDS WILL BE THE MAIN WEATHER FEATURE THIS AFTERNOON.
SOME GUSTS IN EXCESS OF 30 KNOTS OVER WESTERN AREAS IN THE AFTERNOON.
SHOULD SLACKEN A BIT OVERNIGHT AHEAD OF DAKOTAS COLD FRONT. THIS
FRONT IS PROGGED TO MOVE INTO CENTRAL MINNESOTA BY 00Z SUN.
MENTIONED A PROB30 -SHRA DEVELOPING AFTER 14Z SAT...WITH A BETTER
CHANCE OF TSRA WEST DURING THE AFTERNOON. SHOULD SEE JUST A MIX OF
MID/HIGH LEVEL CLOUDS UNTIL FRONT MOVES INTO MINNESOTA. THE FRONT
WILL GRADUALLY MOVE EAST LATE AFTERNOON AND SATURDAY EVENING INTO
WESTERN WISCONSIN SUNDAY.
KMSP...VFR CONDS CONTINUE. MAINLY HIGH CLOUDS WITH LOWERING CEILING
DEVELOPING DURING THE DAY SATURDAY. MENTIONED VCSH BEGINNING AT 19Z
SAT FOR NOW...AS MODELS ARE HINTING AT A WEAK SHORT WAVE LIFTING OUT
AHEAD OF THE COLD FRONT SATURDAY MORNING. WILL HAVE TO MONITOR THIS
FOR LATER TAF ISSUANCE. HELD OFF ON ANY THUNDER MENTION...AS BEST
CHANCE COMES IN WITH THE FRONT SATURDAY NIGHT. STRONG SOUTH WINDS
WILL CONTINUE THIS AFTERNOON...WITH GUST POTENTIAL TO 30 KNOTS
POSSIBLE. THEN WINDS EXPECTED TO SLACKEN A BIT THE
EVENING...INCREASING AHEAD OF THE FRONT AGAIN BY 14Z SAT.
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...WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR BLUE EARTH-BROWN-
CHIPPEWA-FARIBAULT-KANDIYOHI-LAC QUI PARLE-MARTIN-NICOLLET-
POPE-REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT-WATONWAN-YELLOW
MEDICINE.
WI...NONE.
&&
$$
JRB/DWE
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1237 PM CDT FRI MAY 18 2012
.AVIATION...18Z TAF ISSUANCE...
GUSTY SOUTH WINDS THIS AFTERNOON UNDER VFR AND MOSTLY CLEAR SKIES.
COULD SEE SOME MID-LEVEL CONVECTION DEVELOP AROUND OR NORTH OF INL
LATE THIS AFTERNOON. OTHERWISE...MOST AREAS WILL REMAIN VFR
THROUGH TOMORROW MORNING. LLWS WILL DEVELOP ONCE AGAIN
TONIGHT...AND DIMINISH BY MID MORNING SATURDAY. COULD SEE TS IN
THE VICINITY OF BRD AND INL SAT MORNING AS THE MAIN SFC TROUGH
APPROACHES THE AREA FROM THE WEST.
&&
.PREV DISCUSSION... /ISSUED 1158 AM CDT FRI MAY 18 2012/
UPDATE...INCREASED MAX TEMPS TODAY A FEW DEGREES BASED ON SFC OBS
AND 85H TEMPS. LAKEFRONT TEMPS TRICKY AS HI RES MDLS SHOW NE WIND
AT IMMEDIATE LAKEFRONT...EXPANDING INLAND TODAY. SFC TEMPS
ALREADY APPROACHING 80 AT KDYT. ONLY ISSUE OF NOTE TODAY BESIDES
HIGH TEMPS IS POTENTIAL FOR AFTN CONVECTION ACROSS FAR
NORTH. LATEST RUC13 SHOWS MID LVL WARMING CONTINUES TO ADVECT INTO
CWA FROM WEST AND SOUTH...SUGGESTING INCREASED INHIBITION. FCST
DEEP LYR SHEAR/INSTABILITY PARAMETERS SHOW ANY OPPORTUNITY FOR
ORGANIZED ACTIVITY WOULD BE ALONG BORDER AND NORTH INTO CANADA.
REST OF FCST ON TRACK WITH SIGNIFICANT PRECIP POTENTIAL FOR SAT
AFTN INTO SUNDAY AS COLD FRONT MARCHES ACROSS REGION.
PREV DISCUSSION... /ISSUED 633 AM CDT FRI MAY 18 2012/
AVIATION...12Z TAFS
VFR CONDITIONS ARE FORECASTED THROUGH TONIGHT...WITH SCT/BKN HIGH
CLOUDS. HOWEVER...SHOWERS AND THUNDERSTORMS ARE POSSIBLE NEAR AND
NORTH OF THE INTERNATIONAL BORDER THIS AFTERNOON AND INTO
TONIGHT...BUT CONFIDENCE IS LOW AS TO WHETHER KINL WILL BE
AFFECTED BY ANY STORMS. AT THIS POINT...FORECASTED VCTS AT KINL
FROM 22Z TO 03Z. THERE IS ALSO A VERY SLIGHT CHANCE THAT KBRD AND
KHIB COULD BE AFFECTED BY SHOWERS AND STORMS TONIGHT...TOO...BUT
LEFT IT OUT OF THE FORECAST FOR NOW. GUSTY SOUTHERLY WINDS WILL
DEVELOP BY THIS AFTERNOON...AND SOMEWHAT RELAX TONIGHT. WIND
SHEAR WILL REMAIN AN ISSUE THIS MORNING AT KDLH/KHIB/KBRD/KHYR DUE
TO STRONG SOUTHWESTERLY WINDS...BUT THOSE WINDS WILL SIGNIFICANTLY
WEAKEN BY THIS AFTERNOON. WIND SHEAR WILL BE AN ISSUE AGAIN
TONIGHT WHEN THE SOUTHWESTERLY WINDS INCREASE AGAIN.
PREV DISCUSSION... /ISSUED 347 AM CDT FRI MAY 18 2012/
SHORT TERM...THE MAIN SHORT TERM FOCUS IS TEMPERATURES...WINDS
AND PRECIPITATION CHANCES.
SHOWERS AND THUNDERSTORMS HAD GENERALLY MOVED OUT OF THE CWA AS OF
330 AM. SOME SHOWERS WERE STILL NOTED JUST SOUTH OF GRAND PORTAGE
OVER LAKE SUPERIOR. THE WARM FRONT WAS FAIRLY EASY TO PICK OUT
THIS MORNING. THE 3 AM TEMPERATURE AT GRAND RAPIDS WAS 57
DEGREES... WHILE IT WAS 70 AT LONGVILLE AND AITKIN...WITH A SUBTLE
WIND SHIFT FROM SOUTHEAST TO SOUTHWEST.
AS THE WARM SECTOR CONTINUES TO BUILD ACROSS THE NORTHLAND
TODAY...WITH THE WARM FRONT CONTINUING TO MOVE NORTHWARD...WE
SHOULD SEE GENERALLY DRY CONDITIONS FOR MOST OF THE NORTHLAND.
STILL THINK THERE WILL BE SOME SHOWERS AND STORMS ACROSS THE
NORTHERN 1/3 OF THE CWA...AND WILL CONTINUE TO MENTION POPS FOR
THOSE AREAS. TEMPS ARE A BIT TRICKY GIVEN SOME LINGERING CLOUDS...
BUT THINK MOST AREAS WILL REACH THE LOWER TO MIDDLE 80S FOR
DAYTIME HIGHS. H85 TEMPS REACH +18 TO +19C TODAY. THE OTHER ISSUE
TODAY WILL BE GUSTY WINDS...WITH SUSTAINED SOUTHERLY WINDS OF 10
TO 20 MPH WITH GUSTS INTO THE MID 20 MPH RANGE.
THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL CONTINUE TO BE
CONFINED TO THE INTERNATIONAL BORDER REGION TONIGHT...BUT AS THE
NIGHT WEARS ON...THE FOCUS WILL SHIFT NORTHWARD INTO SC CANADA.
WITH LOW PRESSURE MOVING IN FROM THE WEST TONIGHT...SOME SHOWERS
AND STORMS MAY REACH THE WESTERN BORDER OF THE CWA LATE. TEMPS
OVERNIGHT SHOULD REMAIN MILD AS WE REMAIN IN THE WARM SECTOR.
THE COLD FRONT WILL FINALLY MOVE EASTWARD INTO THE CWA ON
SATURDAY. WILL SLOW DOWN THE EASTWARD MOVEMENT ACROSS THE CWA
BASED ON THE 00Z MODEL SET...WITH SHOWERS AND THUNDERSTORMS
BECOMING LIKELY IN THE WESTERN HALF OF THE CWA IN THE AFTERNOON.
TEMPS AHEAD OF THE FRONT SHOULD EASILY GET INTO THE 80S...BUT THEN
BACK OFF AS THE RAIN MOVES IN FOR THE WESTERN ZONES.
LONG TERM...[SATURDAY NIGHT - THURSDAY]
THE MODELS ARE IN REASONABLE AGREEMENT FOR MOST OF THE PERIOD...SO
LEANED ON A BLEND. WET WEATHER IS LIKELY ACROSS THE NORTHLAND AS A
COLD FRONT CONTINUES TO MOVE THROUGH THE EASTERN FA SATURDAY NIGHT
AND SUNDAY. THUNDERSTORMS ARE POSSIBLE THROUGH SUNDAY...BUT MOSTLY
ACROSS THE EASTERN FA. HIGH PRESSURE WILL BEGIN TO TAKE A HOLD OF
THE NORTHLAND SUNDAY NIGHT...BUT THERE MAY BE LINGERING SHOWERS
ACROSS THE EASTERN FA. MONDAY THROUGH TUESDAY LOOKS MILD AND DRY
ACROSS THE NORTHLAND AS HIGH PRESSURE CONTINUES TO INFLUENCE THE
REGION. LOW PRESSURE WILL BEGIN TO ORGANIZE IN THE WESTERN PLAINS IN
EARLY NEXT WEEK...AND SHOWERS AND THUNDERSTORMS ARE POSSIBLE TUESDAY
NIGHT INTO THURSDAY ACROSS THE NORTHLAND AS WARM SOUTHERLY FLOW
INCREASES ACROSS THE REGION.
&&
.POINT TEMPS/POPS...
DLH 82 60 82 57 / 10 0 50 70
INL 87 62 78 48 / 30 50 70 60
BRD 87 65 78 51 / 10 10 70 70
HYR 84 63 85 61 / 10 0 10 70
ASX 84 62 85 58 / 10 0 10 70
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...CANNON
AVIATION...TENTINGER
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1158 AM CDT FRI MAY 18 2012
.UPDATE...INCREASED MAX TEMPS TODAY A FEW DEGREES BASED ON SFC OBS
AND 85H TEMPS. LAKEFRONT TEMPS TRICKY AS HI RES MDLS SHOW NE WIND
AT IMMEDIATE LAKEFRONT...EXPANDING INLAND TODAY. SFC TEMPS
ALREADY APPROACHING 80 AT KDYT. ONLY ISSUE OF NOTE TODAY BESIDES
HIGH TEMPS IS POTENTIAL FOR AFTN CONVECTION ACROSS FAR
NORTH. LATEST RUC13 SHOWS MID LVL WARMING CONTINUES TO ADVECT INTO
CWA FROM WEST AND SOUTH...SUGGESTING INCREASED INHIBITION. FCST
DEEP LYR SHEAR/INSTABILITY PARAMETERS SHOW ANY OPPORTUNITY FOR
ORGANIZED ACTIVITY WOULD BE ALONG BORDER AND NORTH INTO CANADA.
REST OF FCST ON TRACK WITH SIGNIFICANT PRECIP POTENTIAL FOR SAT
AFTN INTO SUNDAY AS COLD FRONT MARCHES ACROSS REGION.
&&
.PREV DISCUSSION... /ISSUED 633 AM CDT FRI MAY 18 2012/
AVIATION...12Z TAFS
VFR CONDITIONS ARE FORECASTED THROUGH TONIGHT...WITH SCT/BKN HIGH
CLOUDS. HOWEVER...SHOWERS AND THUNDERSTORMS ARE POSSIBLE NEAR AND
NORTH OF THE INTERNATIONAL BORDER THIS AFTERNOON AND INTO
TONIGHT...BUT CONFIDENCE IS LOW AS TO WHETHER KINL WILL BE
AFFECTED BY ANY STORMS. AT THIS POINT...FORECASTED VCTS AT KINL
FROM 22Z TO 03Z. THERE IS ALSO A VERY SLIGHT CHANCE THAT KBRD AND
KHIB COULD BE AFFECTED BY SHOWERS AND STORMS TONIGHT...TOO...BUT
LEFT IT OUT OF THE FORECAST FOR NOW. GUSTY SOUTHERLY WINDS WILL
DEVELOP BY THIS AFTERNOON...AND SOMEWHAT RELAX TONIGHT. WIND
SHEAR WILL REMAIN AN ISSUE THIS MORNING AT KDLH/KHIB/KBRD/KHYR DUE
TO STRONG SOUTHWESTERLY WINDS...BUT THOSE WINDS WILL SIGNIFICANTLY
WEAKEN BY THIS AFTERNOON. WIND SHEAR WILL BE AN ISSUE AGAIN
TONIGHT WHEN THE SOUTHWESTERLY WINDS INCREASE AGAIN.
PREV DISCUSSION... /ISSUED 347 AM CDT FRI MAY 18 2012/
SHORT TERM...THE MAIN SHORT TERM FOCUS IS TEMPERATURES...WINDS
AND PRECIPITATION CHANCES.
SHOWERS AND THUNDERSTORMS HAD GENERALLY MOVED OUT OF THE CWA AS OF
330 AM. SOME SHOWERS WERE STILL NOTED JUST SOUTH OF GRAND PORTAGE
OVER LAKE SUPERIOR. THE WARM FRONT WAS FAIRLY EASY TO PICK OUT
THIS MORNING. THE 3 AM TEMPERATURE AT GRAND RAPIDS WAS 57
DEGREES... WHILE IT WAS 70 AT LONGVILLE AND AITKIN...WITH A SUBTLE
WIND SHIFT FROM SOUTHEAST TO SOUTHWEST.
AS THE WARM SECTOR CONTINUES TO BUILD ACROSS THE NORTHLAND
TODAY...WITH THE WARM FRONT CONTINUING TO MOVE NORTHWARD...WE
SHOULD SEE GENERALLY DRY CONDITIONS FOR MOST OF THE NORTHLAND.
STILL THINK THERE WILL BE SOME SHOWERS AND STORMS ACROSS THE
NORTHERN 1/3 OF THE CWA...AND WILL CONTINUE TO MENTION POPS FOR
THOSE AREAS. TEMPS ARE A BIT TRICKY GIVEN SOME LINGERING CLOUDS...
BUT THINK MOST AREAS WILL REACH THE LOWER TO MIDDLE 80S FOR
DAYTIME HIGHS. H85 TEMPS REACH +18 TO +19C TODAY. THE OTHER ISSUE
TODAY WILL BE GUSTY WINDS...WITH SUSTAINED SOUTHERLY WINDS OF 10
TO 20 MPH WITH GUSTS INTO THE MID 20 MPH RANGE.
THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL CONTINUE TO BE
CONFINED TO THE INTERNATIONAL BORDER REGION TONIGHT...BUT AS THE
NIGHT WEARS ON...THE FOCUS WILL SHIFT NORTHWARD INTO SC CANADA.
WITH LOW PRESSURE MOVING IN FROM THE WEST TONIGHT...SOME SHOWERS
AND STORMS MAY REACH THE WESTERN BORDER OF THE CWA LATE. TEMPS
OVERNIGHT SHOULD REMAIN MILD AS WE REMAIN IN THE WARM SECTOR.
THE COLD FRONT WILL FINALLY MOVE EASTWARD INTO THE CWA ON
SATURDAY. WILL SLOW DOWN THE EASTWARD MOVEMENT ACROSS THE CWA
BASED ON THE 00Z MODEL SET...WITH SHOWERS AND THUNDERSTORMS
BECOMING LIKELY IN THE WESTERN HALF OF THE CWA IN THE AFTERNOON.
TEMPS AHEAD OF THE FRONT SHOULD EASILY GET INTO THE 80S...BUT THEN
BACK OFF AS THE RAIN MOVES IN FOR THE WESTERN ZONES.
LONG TERM...[SATURDAY NIGHT - THURSDAY]
THE MODELS ARE IN REASONABLE AGREEMENT FOR MOST OF THE PERIOD...SO
LEANED ON A BLEND. WET WEATHER IS LIKELY ACROSS THE NORTHLAND AS A
COLD FRONT CONTINUES TO MOVE THROUGH THE EASTERN FA SATURDAY NIGHT
AND SUNDAY. THUNDERSTORMS ARE POSSIBLE THROUGH SUNDAY...BUT MOSTLY
ACROSS THE EASTERN FA. HIGH PRESSURE WILL BEGIN TO TAKE A HOLD OF
THE NORTHLAND SUNDAY NIGHT...BUT THERE MAY BE LINGERING SHOWERS
ACROSS THE EASTERN FA. MONDAY THROUGH TUESDAY LOOKS MILD AND DRY
ACROSS THE NORTHLAND AS HIGH PRESSURE CONTINUES TO INFLUENCE THE
REGION. LOW PRESSURE WILL BEGIN TO ORGANIZE IN THE WESTERN PLAINS IN
EARLY NEXT WEEK...AND SHOWERS AND THUNDERSTORMS ARE POSSIBLE TUESDAY
NIGHT INTO THURSDAY ACROSS THE NORTHLAND AS WARM SOUTHERLY FLOW
INCREASES ACROSS THE REGION.
&&
.POINT TEMPS/POPS...
DLH 82 60 82 57 / 10 0 50 70
INL 87 62 78 48 / 30 50 70 60
BRD 87 65 78 51 / 10 10 70 70
HYR 84 63 85 61 / 10 0 10 70
ASX 84 62 85 58 / 10 0 10 70
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...CANNON
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
947 PM CDT Sat May 19 2012
.UPDATE...
/938 PM CDT Sat May 19 2012/
00Z TOP sounding and latest AMDAR soundings out of MCI show quite a
bit of low-level dry air and convective inhibition which has made it
very difficult for convection to survive into eastern KS this evening.
As we continue to lose daytime heating this evening, convective
potential will become more dependent on the placement of the 850 hPa
jet and the slightly enhanced elevated theta-e that it feeds into
these storms. Latest RUC analysis shows a somewhat split pattern to
the LLJ with a northern focus near Omaha and a secondary maximum over
southern KS. Not surprisingly the best convective development has
been focused across these areas this evening. Still cannot rule out
some convective development in between these two areas later tonight
as the two jet maxima merge toward 06Z. Would need quite a bit of
theta-e advection at 850 hPa to break the capping inversion that is
evident on the 00Z TOP sounding, so will keep PoPs limited to low
chance overnight. Any storm that does develop over our area should
remain sub severe as better midlevel winds remain to the north and
west of the forecast area.
Hawblitzel
&&
.DISCUSSION...
Short Range (Today through Monday)...
This morning showers and thunderstorms developed on the edge of the
low level jet, where moisture convergence was maximized, though by
noon the storms had mostly dissipated as the jet mixed out with the
expanding boundary layer, leaving only isolated sprinkles and a
modest mid-level cloud deck moving east into Missouri. Farther
afield, a cold front is noted stretched from Minnesota south
southwest through eastern Nebraska, central Kansas, into the
panhandles of Oklahoma and Texas, and it will be this fronts
movement through Kansas and Missouri tonight into Sunday which will
be the focus for stormy activity. Otherwise, of note is a shortwave
currently exiting eastern Colorado, which will lift towards the
upper Great Lakes overnight and through Sunday. This movement will
help push the cold front wallowing to our west through eastern
Kansas and western Missouri late tonight through Sunday.
Tonight and Sunday...afternoon SPC analysis shows shows 1500-2000
J/KG of MLCAPE across east central Kansas and northwest Missouri
this afternoon, but it also shows MLCIN greater than -150 J/KG which
seems reasonable given the local ascent soundings from 1830Z at the
KMCI terminal, which shows a decent dry layer present between 850mb
and 600mb. Add to this the cloud cover across the region due to this
mornings fading storms, and convective initiation looks like it will
have to wait till late this afternoon to occur, likely in the
vicinity of the front which will still be in north central to
northeast Kansas. Moisture will be a somewhat limiting factor as
dewpoints have struggled to rise much beyond 60 degrees, with many
locations not even achieving that. Shear, especially in the cloud
baring layers away from the immediate vicinity of the front, is not
particularly high in the pre-frontal environment, so expectations
are that storms will have a very low potential for severe weather
outside of the far northwest corner of Missouri and adjacent areas
of extreme northeast Kansas, where large hail and strong winds would
be possible as the front arrives coincident with any thunderstorms.
Verity of models all share this outlook on the forecast, though they
also share an expectation that the main focus for activity will
shift to our north, as a jet streak rounds to shortwave and heads
northeast, and south, as what little low level jet is present late
tonight enhances convergences across south central Kansas and
Oklahoma. So, while confidence that some precipitation will develop
and fall in the forecast area tonight, the advertised scattered
nature of the storms that will move in seem to warrant only a
chance POP for the overnight hours. Otherwise, storms may persist
through Sunday, shifting east into areas from northeast to central
and west central Missouri during the afternoon hours. While shear is
better in the post-frontal environment, instability will not be, so
no severe thunderstorm activity is expected.
Otherwise, looking at Monday, expect temperatures to range around to
just below normal for the day (which in later half of May means
beautiful conditions) as mostly sunny skies and north to northeast
winds make for a pleasant start to the work week.
Cutter
Medium Range (Tuesday through Saturday)...
This extended period of the forecast will be marked by dry
conditions and temperatures jumping to 10F+ degrees above normal.
Through the middle of this upcoming week, an area of surface high
pressure will shift just east of the area, dominating much of the
eastern and southeastern U.S. This surface pattern will result in a steady
southerly flow into the region, which will help support the rise in
temperatures. Tuesday into Wednesday, models show an area of low
pressure moving eastward into the Northern Plains and sagging
southward into the western part of the Central Plains. However,
thanks to an upper level ridge that will build in across much of the
eastern CONUS, this surface low will essentially be blocked from
entering into the forecast area due to this strong ridge. As a
result, any precipitation associated with this area of low pressure
looks to stay north and west of the region. Models show this
upper ridge remaining firmly in place through the end of the period.
One discrepancy amongst the models comes into play for the end of
the week with regards to whether or not the potential for
precipitation exists. GFS shows an upper level trough dropping
southward enough into the extreme Northern Plains that it may push
some of the precipitation from the surface low down into extreme
northeast Kansas and extreme northwest Missouri. Other models though
keep the trough in southern Canada which would limit the potential
for the precipitation to be pushed southward into the area. As a
result, have nothing more than slight chance pops Thursday night and
Friday across the extreme northwest corner of the forecast area.
As for temperatures, with the persistent southerly flow in place,
conditions on Tuesday will be a few degrees above normal and the
warming trend will continue through the period. Mild conditions are
expected for the latter half of the week and into next weekend as
temperatures steadily soar into the middle to upper 80s -- and
possibly into the lower 90s.
ACH
&&
.AVIATION...
For the 00Z TAFs...cold front over central KS has sparked off a
broken line of strong convection that is slowly progressing eastward.
This activity is expected to have a difficult time making it as far
east as the MO/KS border due to dry air in place per latest AMDAR
soundings out of MCI. Still, cannot rule out some weaker convection
developing later tonight as the cold front approaches and a weak LLJ
transports better moisture into the area. Will therefore keep the
VCTS wording for later this evening due to low chances of convection
near the western MO terminals. May see some MVFR cigs after the front
pushes through early Sunday morning, but upstream obs indicate more
VFR than MVFR so kept cigs more optimistic for now.
Hawblitzel
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
918 PM MDT SAT MAY 19 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH MONDAY...
SHALLOW UPPER TROUGH AND WEAK BOUNDARY ALONG THE INTERNATIONAL
BORDER HAS SPREAD LOW BROKEN CLOUDS ACROSS THE AREA WITH
ISOLATED SHOWERS. WENT AHEAD AND SPREAD ISOLATED SHOWERS WITH LOW
QPF FARTHER EAST ACROSS NEMONT TONIGHT BASED ON RAP GUIDANCE AND
RADAR. MADE ADDITIONAL MINOR TWEAKS TO TEMPERATURES AND WINDS. SCT
EARLY UPDATE BASED ON RADAR ECHOES...
A WEAK SHORTWAVE MOVING ACROSS NORTHEAST MONTANA THIS EVENING IS
PRODUCING LOW LEVEL CLOUDS AND RADAR ECHOES IN NORTHERN PHILLIPS
COUNTY AND NORTHERN VALLEY COUNTY. THE ONLY MODEL THAT IS PICKING
UP ON THIS NOW IS THE RAPID REFRESH MODEL (RAP). WITH A SURFACE
HIGH IN PLACE OVER NEMONT MOST OF THE ECHOES ARE LIKELY NOT
REACHING THE GROUND WITH ENOUGH RAIN TO AMOUNT TO MUCH. BUT WENT
AHEAD A BUMPED POPS A BIT TO ISOLATED FOR THE POSSIBILITY OF A FEW
AREAS OF SHOWERS REACHING THE GROUND...SINCE TEMPERATURES ARE ONLY
IN THE 50S ALONG THE INTERNATIONAL BORDER. THE RAP INDICATES THAT
THE SHOWERS WILL DIMINISH AS THEY MOVE EAST THIS EVENING. SO
CONFINED SHOWERS TO THE NW. SCT
PREVIOUS DISCUSSION...
WATER VAPOR IMAGERY AND 500 MB HEIGHT FIELD SHOWS A SIMILAR AND
SLIGHTLY LESS ACTIVE PATTERN THAN YESTERDAY. A LOW PRESSURE
CIRCULATION OFF THE SOUTH CAROLINA COAST HAS BECOME THE FIRST
TROPICAL OF THE ATLANTIC HURRICANE SEASON WHILE INTRODUCING SOME
SCATTERED THUNDERSTORMS INTO THE INTERIOR SOUTHEAST. HIGH PRESSURE
CONTINUES TO HOLD SWAY OVER THE LOWER MISSISSIPPI AND OHIO RIVER
VALLEYS. THE SLOW- MOVING UPPER TROUGH WHICH HAS FINALLY EMERGED
ONTO THE CENTRAL HIGH PLAINS CONTINUES TO SPAWN THUNDERSTORMS
THERE. THUNDERSTORMS ARE ALSO SETTING OFF OVER SOUTHERN FLORIDA.
REGIONALLY FOR US...AS THE NORTHERN ROCKIES AND NORTHERN HIGH
PLAINS COMES AWAY FROM THE LARGER UPPER LEVEL TROUGH...ZONAL FLOW
IS OSCILLATING WITH A WEAK TROUGH TO STILL ALLOW PARTLY CLOUDY
SKIES AND A FEW SPRINKLES...ESPECIALLY OVER NORTH CENTRAL MONTANA.
LOCALLY...SURFACE HIGH PRESSURE IS KEEPING SKIES MOSTLY SUNNY OVER
OUR CENTRAL AND EASTERN ZONES...WHILE A WEAK INVERTED SURFACE
TROUGH IS PROVIDING ENOUGH LIFT TO SPREAD SOME MID TO UPPER LEVEL
CLOUDS OVER CENTRAL MONTANA AND INTO OUR FAR WESTERN ZONES THIS
AFTERNOON. TODAY...WITH THE RELATIVELY DRY AIR IN PLACE...I DO NOT
EXPECT THIS INCREASE IN CLOUDINESS TO BRING MUCH MORE THAN SOME
ISOLATED LIGHT VIRGA RAIN SHOWERS OR SPRINKLES TO OUR WESTERN AND
NORTHWESTERN ZONES TODAY AND TONIGHT.
SUNDAY AND MONDAY...WEAK UPPER LEVEL RIDGING TAKES OVER ACROSS
MONTANA AS TEMPERATURES CLIMB INTO THE 70S AND 80S RESPECTFULLY.
THERE MAY BE JUST ENOUGH MID LEVEL MOISTURE TO SET OF SOME AREA
VIRGA SHOWERS OR SPRINKLES AROUND THE PERIMETER EDGES OF OUR
CWA...SIMILAR TO TODAY.
A LARGE AND STRONG UPPER LEVEL TROUGH THEN SPREADS INTO THE
PACIFIC NORTHWEST TOWARD THE END OF THIS SHORT TERM FORECAST
PERIOD...BRINGING A SOUTHWEST FLOW ALOFT AND INCREASED CLOUDINESS
TO OUR REGION. BMICKELSON
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...
LONG WAVE TROF DIGGING ACROSS THE WESTERN STATES DOMINATES THE
EXTENDED PERIOD. MODELS DIFFERING MAINLY ON WHERE THE MOISTURE
AND ENERGY WILL AT VARIOUS TIMES IN THE EVOLUTION OF THE SYSTEM.
OVERALL MAIN ADJUSTMENT WAS TO BACK OFF SLIGHTLY ON THE POPS WITH
THE SUGGESTED SPLITTING OF THE SYSTEM AND FOCUS OF THE MAIN LOW
OVER THE GREAT BASIN. EBERT
PREVIOUS LONG TERM DISCUSSION...UPPER RIDGE MOVES TO THE EAST
MONDAY NIGHT AND SOUTHWEST FLOW ALOFT WILL PREVAIL AHEAD OF AN
UPPER LOW THAT MOVES INTO THE AREA BY WEDNESDAY. THERE WILL BE A
COLD FRONT MOVING THROUGH EASTERN MONTANA DURING THE DAY ON
TUESDAY. AIRMASS ALONG AND AHEAD OF THE FRONT SHOULD BE UNSTABLE
ENOUGH TO SUPPORT SOME THUNDERSTORMS. MODELS HAVE VARIED ON WHERE
THE BEST INSTABILITY WILL BE. WILL MENTION A CHANCE OF
THUNDERSTORMS.
THE GFS AND ECMWF PLACE THE UPPER LOW DIFFERENTLY ON WEDNESDAY AND
WEDNESDAY NIGHT WITH GFS FAVORING MONTANA AND ECMWF PUTTING THE
LOW IN SASKATCHEWAN. BOTH MODELS HAVE EASTERN MONTANA IN A DRY
SLOT FOR AT LEAST PART OF THE DAY. HOWEVER...THAT WILL ALLOW FOR
DAYTIME HEATING TO DESTABILIZE THE ATMOSPHERE. MAY SEE SOME
SHOWERS AND THUNDERSTORMS DEVELOP AS A RESULT. WILL MENTION A
CHANCE FOR NOW.
THE MODEL DIFFERENCES CONTINUE THURSDAY WITH THE ECMWF KEEPING THE
UPPER LOW IN SASKATCHEWAN AND DRY SLOT OVER EASTERN MONTANA WHILE
THE GFS TRACKS ITS UPPER LOW INTO NORTH DAKOTA AND MANITOBA. WILL
MAINTAIN A CHANCE OF SHOWERS GIVEN THE UNCERTAINTY.
FRIDAY AND SATURDAY...THE NEXT UPPER LOW DIGS SOUTH INTO NORTHERN
CALIFORNIA WITH RIDGE TO THE EAST. MONTANA WILL BE IN A SOMEWHAT
MOIST SOUTHWEST FLOW ALOFT. WILL MAINTAIN A CHANCE OF SHOWERS FOR
NOW. FORRESTER
&&
.AVIATION...
VFR. A FEW EVENING SHOWERS WILL MOVE THROUGH THE REGION. THEN
AFTER 06Z LOOK FOR CLEARING SKIES AND LIGHT WIND WHICH WILL
DOMINATE THROUGH SUNDAY. PROTON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
707 PM MDT SAT MAY 19 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH MONDAY...
EARLY UPDATE BASED ON RADAR ECHOES...A WEAK SHORTWAVE MOVING
ACROSS NORTHEAST MONTANA THIS EVENING IS PRODUCING LOW LEVEL
CLOUDS AND RADAR ECHOES IN NORTHERN PHILLIPS COUNTY AND NORTHERN
VALLEY COUNTY. THE ONLY MODEL THAT IS PICKING UP ON THIS NOW IS
THE RAPID REFRESH MODEL (RAP). WITH A SURFACE HIGH IN PLACE OVER
NEMONT MOST OF THE ECHOES ARE LIKELY NOT REACHING THE GROUND WITH
ENOUGH RAIN TO AMOUNT TO MUCH. BUT WENT AHEAD A BUMPED POPS A BIT
TO ISOLATED FOR THE POSSIBILITY OF A FEW AREAS OF SHOWERS REACHING
THE GROUND...SINCE TEMPERATURES ARE ONLY IN THE 50S ALONG THE
INTERNATIONAL BORDER. THE RAP INDICATES THAT THE SHOWERS WILL
DIMINISH AS THEY MOVE EAST THIS EVENING. SO CONFINED SHOWERS TO
THE NW. SCT
PREVIOUS DISCUSSION...
WATER VAPOR IMAGERY AND 500 MB HEIGHT FIELD SHOWS A SIMILAR AND
SLIGHTLY LESS ACTIVE PATTERN THAN YESTERDAY. A LOW PRESSURE
CIRCULATION OFF THE SOUTH CAROLINA COAST HAS BECOME THE FIRST
TROPICAL OF THE ATLANTIC HURRICANE SEASON WHILE INTRODUCING SOME
SCATTERED THUNDERSTORMS INTO THE INTERIOR SOUTHEAST. HIGH PRESSURE
CONTINUES TO HOLD SWAY OVER THE LOWER MISSISSIPPI AND OHIO RIVER
VALLEYS. THE SLOW-MOVING UPPER TROUGH WHICH HAS FINALLY EMERGED
ONTO THE CENTRAL HIGH PLAINS CONTINUES TO SPAWN THUNDERSTORMS
THERE. THUNDERSTORMS ARE ALSO SETTING OFF OVER SOUTHERN FLORIDA.
REGIONALLY FOR US...AS THE NORTHERN ROCKIES AND NORTHERN HIGH
PLAINS COMES AWAY FROM THE LARGER UPPER LEVEL TROUGH...ZONAL FLOW
IS OSCILLATING WITH A WEAK TROUGH TO STILL ALLOW PARTLY CLOUDY
SKIES AND A FEW SPRINKLES...ESPECIALLY OVER NORTH CENTRAL MONTANA.
LOCALLY...SURFACE HIGH PRESSURE IS KEEPING SKIES MOSTLY SUNNY OVER
OUR CENTRAL AND EASTERN ZONES...WHILE A WEAK INVERTED SURFACE
TROUGH IS PROVIDING ENOUGH LIFT TO SPREAD SOME MID TO UPPER LEVEL
CLOUDS OVER CENTRAL MONTANA AND INTO OUR FAR WESTERN ZONES THIS
AFTERNOON. TODAY...WITH THE RELATIVELY DRY AIR IN PLACE...I DO NOT
EXPECT THIS INCREASE IN CLOUDINESS TO BRING MUCH MORE THAN SOME
ISOLATED LIGHT VIRGA RAIN SHOWERS OR SPRINKLES TO OUR WESTERN AND
NORTHWESTERN ZONES TODAY AND TONIGHT.
SUNDAY AND MONDAY...WEAK UPPER LEVEL RIDGING TAKES OVER ACROSS
MONTANA AS TEMPERATURES CLIMB INTO THE 70S AND 80S RESPECTFULLY.
THERE MAY BE JUST ENOUGH MID LEVEL MOISTURE TO SET OF SOME AREA
VIRGA SHOWERS OR SPRINKLES AROUND THE PERIMETER EDGES OF OUR
CWA...SIMILAR TO TODAY.
A LARGE AND STRONG UPPER LEVEL TROUGH THEN SPREADS INTO THE
PACIFIC NORTHWEST TOWARD THE END OF THIS SHORT TERM FORECAST
PERIOD...BRINGING A SOUTHWEST FLOW ALOFT AND INCREASED CLOUDINESS TO
OUR REGION. BMICKELSON
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...
LONG WAVE TROF DIGGING ACROSS THE WESTERN STATES DOMINATES THE
EXTENDED PERIOD. MODELS DIFFERING MAINLY ON WHERE THE MOISTURE
AND ENERGY WILL AT VARIOUS TIMES IN THE EVOLUTION OF THE SYSTEM.
OVERALL MAIN ADJUSTMENT WAS TO BACK OFF SLIGHTLY ON THE POPS WITH
THE SUGGESTED SPLITTING OF THE SYSTEM AND FOCUS OF THE MAIN LOW
OVER THE GREAT BASIN. EBERT
PREVIOUS LONG TERM DISCUSSION...UPPER RIDGE MOVES TO THE EAST
MONDAY NIGHT AND SOUTHWEST FLOW ALOFT WILL PREVAIL AHEAD OF AN
UPPER LOW THAT MOVES INTO THE AREA BY WEDNESDAY. THERE WILL BE A
COLD FRONT MOVING THROUGH EASTERN MONTANA DURING THE DAY ON
TUESDAY. AIRMASS ALONG AND AHEAD OF THE FRONT SHOULD BE UNSTABLE
ENOUGH TO SUPPORT SOME THUNDERSTORMS. MODELS HAVE VARIED ON WHERE
THE BEST INSTABILITY WILL BE. WILL MENTION A CHANCE OF
THUNDERSTORMS.
THE GFS AND ECMWF PLACE THE UPPER LOW DIFFERENTLY ON WEDNESDAY AND
WEDNESDAY NIGHT WITH GFS FAVORING MONTANA AND ECMWF PUTTING THE
LOW IN SASKATCHEWAN. BOTH MODELS HAVE EASTERN MONTANA IN A DRY
SLOT FOR AT LEAST PART OF THE DAY. HOWEVER...THAT WILL ALLOW FOR
DAYTIME HEATING TO DESTABILIZE THE ATMOSPHERE. MAY SEE SOME
SHOWERS AND THUNDERSTORMS DEVELOP AS A RESULT. WILL MENTION A
CHANCE FOR NOW.
THE MODEL DIFFERENCES CONTINUE THURSDAY WITH THE ECMWF KEEPING THE
UPPER LOW IN SASKATCHEWAN AND DRY SLOT OVER EASTERN MONTANA WHILE
THE GFS TRACKS ITS UPPER LOW INTO NORTH DAKOTA AND MANITOBA. WILL
MAINTAIN A CHANCE OF SHOWERS GIVEN THE UNCERTAINTY.
FRIDAY AND SATURDAY...THE NEXT UPPER LOW DIGS SOUTH INTO NORTHERN
CALIFORNIA WITH RIDGE TO THE EAST. MONTANA WILL BE IN A SOMEWHAT
MOIST SOUTHWEST FLOW ALOFT. WILL MAINTAIN A CHANCE OF SHOWERS FOR
NOW. FORRESTER
&&
.AVIATION...
VFR. A FEW EVENING SHOWERS WILL MOVE THROUGH THE REGION. THEN
AFTER 06Z LOOK FOR CLEARING SKIES AND LIGHT WIND WHICH WILL
DOMINATE THROUGH SUNDAY. PROTON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
307 PM MDT FRI MAY 18 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY...
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...
SCATTERED SHOWERS THIS EVENING WILL MOVE EAST INTO NORTH DAKOTA
THIS EVENING WITH CLEARING SKIES TO FOLLOW. WINDS WILL SWITCH
AROUND TO THE NORTHWEST AND INCREASE SLIGHTLY TO 10 TO 20 KTS THIS
EVENING. THE WINDS ARE EXPECTED TO CONTINUE AT SIMILAR SPEEDS
SATURDAY. JAMBA
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
949 AM MDT FRI MAY 18 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SUNDAY...
RAIN SHOWERS THIS MORNING DIMINISHING OVER SOME LOCATIONS AND
PERSISTING AND EVEN INCREASING OVER OTHERS. UPDATED THE FORECAST
TODAY TO REFLECT THE MORE ACCURATE HRRR DEPICTION OF EXPECTED
PRECIPITATION WHICH INCREASES OVER OUR SOUTHEASTERN ZONES THIS
AFTERNOON. ALSO INCLUDED A SLIVER OF THUNDERSTORM MENTION OVER OUR
FAR EASTERN ZONES TO SUPPORT SPC OUTLOOK FOR GENERAL THUNDERSTORMS
THIS AFTERNOON. BMICKELSON
PREVIOUS SHORT TERM DISCUSSION...BROAD AREA OF RAIN LIFTING
ACROSS NORTHEAST MONTANA EARLY THIS MORNING. HEAVIEST RAINFALL
LOOKS TO BE ASSOCIATED WITH FORCING ALONG THE 700MB FRONT AS IT
MOVES INTO THE WESTERN ZONES...AND PUSHED NORTH BY SHORTWAVE
LIFTING ACROSS SOUTH CENTRAL MONTANA. AS UPPER TROF CONTINUES TO
PUSH THROUGH THE GREAT BASIN...MOISTURE STREAMING NORTH COULD
RESULT IN ADDITIONAL SHOWERS ACROSS EASTERN MONTANA TODAY.
UPPER TROF AXIS SWINGS ACROSS MONTANA OVERNIGHT BRINGING THE
THREAT OF SHOWERS TO AN END. SATURDAY WILL BE DRY BUT COOL WITH
HIGH PRESSURE OVER THE STATE AND WEAK CYCLONIC FLOW. UPPER RIDGE
BEGINS TO REBOUND OVER THE NORTHERN ROCKIES ON SUNDAY AND HIGH
PRESSURE MOVING EAST WILL ALLOW FOR RETURN FLOW PUSHING WARMER AIR
INTO THE STATE. EBERT
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
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...
VFR WITH ANY MVFR CONDITIONS TO THE NORTH OF THE TAF SITES
EVAPORATING TODAY. SOME CEILINGS OF 4K TO 7K ARE EXPECTED AT MOST
SITES TODAY THAT WILL LIFT THIS EVENING. ISOLATED SHOWERS ARE POSSIBLE.
WINDS WILL BECOME NW FROM WEST TO EAST THIS AFTERNOON AT 10 TO 15
KTS. JAMBA
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
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...TAYLOR
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1213 AM CDT FRI MAY 18 2012
.AVIATION...06Z KGRI TAF. VFR CONDITIONS TO CONTINUE THROUGH THE
NEXT 24 HOURS. PRIMARY CONCERN THROUGH THE NEXT 24 HOURS WILL BE
SURFACE WINDS...WITH SUSTAINED SOUTHERLY WINDS INCREASING TO
AROUND 25KTS...AND GUSTING TO AROUND 35KTS...BY LATE FRIDAY
MORNING OR EARLY FRIDAY AFTERNOON AS BOUNDARY LAYER MIXING DEEPENS
DUE TO DIABATIC HEATING. SURFACE WINDS WILL THEN DIMINISH BY 02Z
AS DIABATIC HEATING IS LOST AND THE BOUNDARY LAYER DECOUPLES FROM
THE STRONGER WINDS ALOFT. THE LOW LEVEL PRESSURE GRADIENT SHOULD
KEEP SUSTAINED SURFACE WINDS UP AROUND 15KTS THROUGH SUNRISE
FRIDAY...THUS PREVENTING THE ONSET OF LLWS. LLWS HAS BEEN KEPT OUT
OF THE TAF AS A RESULT...BUT IT IS IMPORTANT TO NOTE THAT LLWS
INSERTION MAY BE NEEDED IF SURFACE WINDS DO MANAGE TO WEAKEN MUCH
BELOW 15KTS THROUGH SUNRISE FRIDAY.
&&
.PREV DISCUSSION... /ISSUED 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.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION...BRYANT
SHORT TERM...ROSSI
LONG TERM...WESELY
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
406 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 /20Z FRIDAY THROUGH WEDNESDAY/...
HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH THE TAF PERIOD.
INCREASING LOW LEVEL MOISTURE ALONG THE OHIO RIVER WILL BRING SOME
RIVER FOG TO THE SRN TAF SITES. KCVG SHOULD HAVE A PERIOD OF MVFR
VSBY RESTRICTIONS WITH KLUK LIKELY FLUCTUATING BETWEEN IFR TO
VLIFR CONDITIONS. FOG SHOULD BE SHALLOW AND SHOULD BURN OFF BY
13Z. SOME DIURNAL CUMULUS CLOUDS ALONG WITH A MIX OF SOME HIGH
CLOUDS ARE EXPECTED BY SATURDAY AFTERNOON.
OUTLOOK...THUNDERSTORMS 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...HICKMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1022 AM EDT FRI MAY 18 2012
.SYNOPSIS...
A HIGH PRESSURE RIDGE WILL BE ACROSS THE AREA THROUGH THE
WEEKEND. A WEAK COLD FRONT WILL MOVE ACROSS THE REGION MONDAY.
&&
.NEAR TERM /UNTIL 9 PM THIS EVENING/...
12Z SOUNDINGS SHOW A SHARP SURFACE INVERSION AGAIN THIS MORNING
WITH VERY DRY LOW LEVEL CONDITIONS. THE DTX SOUNDING SHOWS THE MID
LEVEL MOISTURE FROM 600-700 MB WHICH AGREES WELL WITH THE PATCHY
MID LEVEL CLOUDS THAT ARE ERODING AS THEY MOVE SOUTHEAST TOWARD LAKE
ERIE. THE MORNING SOUNDINGS SUPPORT WARMER TEMPERATURES THAN
CURRENTLY FORECAST ESPECIALLY AWAY FROM LAKE ERIE SO WILL RAISE
READINGS TO NEAR THE HRRR MODEL WHERE HIGHS WILL REACH INTO THE
LOWER 80S. SINCE CLOUDS ARE ERODING AS THE MOVE SOUTHEAST...WILL
LESSEN FORECAST CLOUD COVER FOR THE AFTERNOON AND GO WITH SUNNY TO
MOSTLY SUNNY.
&&
.SHORT TERM /9 PM THIS EVENING THROUGH MONDAY NIGHT/...
HIGH PRESSURE AND DRY AIR REMAIN IN PLACE THROUGH THE WEEKEND WITH
TEMPS WARMING INTO THE LOWER AND MID 80S SATURDAY AND SUNDAY.
MONDAY A WEAK COLD FRONT WILL MOVE THROUGH THE AREA. WILL BRING IN
LOW CHANCE POPS FROM THE WEST SUNDAY NIGHT. MONDAY WILL HAVE LOW
CHANCE POPS WEST HALF AND SLIGHT CHANCE EAST...RAISING TO CHANCE
EVERYWHERE TUESDAY. GFS SHOWS WEAK LOW PRESSURE ACROSS CENTRAL
OHIO IN A...BY THEN...FAIRLY MOIST ENVIRONMENT. TEMPS STILL ABOVE
NORMAL ALTHOUGH DOWN A FEW DEGREES FROM THE WEEKEND.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
FAIRLY BROAD DISORGANIZED UPPER LEVEL TROUGH WILL PERSIST OVER THE
AREA TUESDAY AND WEDNESDAY AND THEN FINALLY EJECT OUT TO THE EAST
COAST BY NEXT THURSDAY. MEANWHILE...UPPER LEVEL RIDGE BUILDS EAST
OVER THE LOCAL REGION FOR THE END OF THE WEEK.
WEAK SURFACE LOW PRESSURE IS RATHER SLUGGISH IN ITS FORWARD MOTION
MOVING EAST OUT OF THE AREA. MOISTURE ASSOCIATED WITH THE LOW
PRESSURE SYSTEM WILL LINGER IN THE AREA AS WELL TUESDAY AND
WEDNESDAY.
WEAK HIGH PRESSURE AT THE SURFACE BUILDS IN OVER THE AREA WEDNESDAY
AFTERNOON INTO THURSDAY. WARM FRONT LIFTS WELL NORTH BY THURSDAY
AFTERNOON PLACING THE AREA INTO THE WARM SECTOR. MODELS ARE REALLY
HINTING AT SUMMER RETURNING TO THE FORECAST AREA AS WE APPROACH THE
WEEKEND. EXPECTING VALUES AROUND 570 AT 1000 TO 500 MB THICKNESS BY
THURSDAY AFTERNOON. SOUTH FLOW WILL ALSO DEVELOP IN THE WAKE OF THE
WARM FRONT AND THIS SHOULD ORIGINATE RIGHT OUT OF THE DEEP SOUTH.
LONG RANGE MODELS SEEM TO BE IN AGREEMENT WITH THIS SCENARIO AS IT
UNFOLDS.
DROPPED BACK TEMPERATURES A FEW DEGREES TUESDAY DUE TO SHOWER THREAT
BUT BOOSTED THEM A COUPLE WEDNESDAY INTO THURSDAY AS SHOWERS BEGIN
TO EXIT THE AREA.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
MID LEVEL CLOUDS COMING ACROSS THE LAKE FROM THE NORTHEAST ARE
DISSIPATING AS THEY ARE ENTERING DRIER AIR. THE REGION REMAINS UNDER
THE INFLUENCE OF HIGH PRESSURE WHICH IS INHIBITING CLOUD GROWTH.
LAKE BREEZE EXPECTED TO DEVELOP AT ERIE AND CLEVELAND DURING THE DAY
AND THEN LAND BREEZE SETS UP. WINDS SHOULD REMAIN BELOW 10 KNOTS.
.OUTLOOK...NON-VFR CONDITIONS MAY DEVELOP NEAR THUNDERSTORMS MONDAY
AND TUESDAY.
&&
.MARINE...
RELATIVELY QUIET ON THE LAKE THROUGH THE NEXT 5 DAYS. GENERALLY
LOOKING AT WAVES OF 2 FEET OR LESS. STAGNANT LIGHT OR WEAK FLOW WILL
PERSIST THROUGH THE PERIOD.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...REL
SHORT TERM...TK
LONG TERM...LOMBARDY
AVIATION...SJ/LOMBARDY
MARINE...LOMBARDY
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
932 AM EDT FRI MAY 18 2012
.SYNOPSIS...
A HIGH PRESSURE RIDGE WILL BE ACROSS THE AREA THROUGH THE
WEEKEND. A WEAK COLD FRONT WILL MOVE ACROSS THE REGION MONDAY.
&&
.NEAR TERM /UNTIL 9 PM THIS EVENING/...
12Z SOUNDINGS SHOW A SHARP SURFACE INVERSION AGAIN THIS MORNING
WITH VERY DRY LOW LEVEL CONDITIONS. THE DTX SOUNDING SHOWS THE MID
LEVEL MOISTURE FROM 600-700 MB WHICH AGREES WELL WITH THE PATCHY
MID LEVEL CLOUDS THAT ARE ERODING AS THEY MOVE SOUTHEAST TOWARD LAKE
ERIE. THE MORNING SOUNDINGS SUPPORT WARMER TEMPERATURES THAN
CURRENTLY FORECAST ESPECIALLY AWAY FROM LAKE ERIE SO WILL RAISE
READINGS TO NEAR THE HRRR MODEL WHERE HIGHS WILL REACH INTO THE
LOWER 80S. SINCE CLOUDS ARE ERODING AS THE MOVE SOUTHEAST...WILL
LESSEN FORECAST CLOUD COVER FOR THE AFTERNOON AND GO WITH SUNNY TO
MOSTLY SUNNY.
&&
.SHORT TERM /9 PM THIS EVENING THROUGH MONDAY NIGHT/...
HIGH PRESSURE AND DRY AIR REMAIN IN PLACE THROUGH THE WEEKEND WITH
TEMPS WARMING INTO THE LOWER AND MID 80S SATURDAY AND SUNDAY.
MONDAY A WEAK COLD FRONT WILL MOVE THROUGH THE AREA. WILL BRING IN
LOW CHANCE POPS FROM THE WEST SUNDAY NIGHT. MONDAY WILL HAVE LOW
CHANCE POPS WEST HALF AND SLIGHT CHANCE EAST...RAISING TO CHANCE
EVERYWHERE TUESDAY. GFS SHOWS WEAK LOW PRESSURE ACROSS CENTRAL
OHIO IN A...BY THEN...FAIRLY MOIST ENVIRONMENT. TEMPS STILL ABOVE
NORMAL ALTHOUGH DOWN A FEW DEGREES FROM THE WEEKEND.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
FAIRLY BROAD DISORGANIZED UPPER LEVEL TROUGH WILL PERSIST OVER THE
AREA TUESDAY AND WEDNESDAY AND THEN FINALLY EJECT OUT TO THE EAST
COAST BY NEXT THURSDAY. MEANWHILE...UPPER LEVEL RIDGE BUILDS EAST
OVER THE LOCAL REGION FOR THE END OF THE WEEK.
WEAK SURFACE LOW PRESSURE IS RATHER SLUGGISH IN ITS FORWARD MOTION
MOVING EAST OUT OF THE AREA. MOISTURE ASSOCIATED WITH THE LOW
PRESSURE SYSTEM WILL LINGER IN THE AREA AS WELL TUESDAY AND
WEDNESDAY.
WEAK HIGH PRESSURE AT THE SURFACE BUILDS IN OVER THE AREA WEDNESDAY
AFTERNOON INTO THURSDAY. WARM FRONT LIFTS WELL NORTH BY THURSDAY
AFTERNOON PLACING THE AREA INTO THE WARM SECTOR. MODELS ARE REALLY
HINTING AT SUMMER RETURNING TO THE FORECAST AREA AS WE APPROACH THE
WEEKEND. EXPECTING VALUES AROUND 570 AT 1000 TO 500 MB THICKNESS BY
THURSDAY AFTERNOON. SOUTH FLOW WILL ALSO DEVELOP IN THE WAKE OF THE
WARM FRONT AND THIS SHOULD ORIGINATE RIGHT OUT OF THE DEEP SOUTH.
LONG RANGE MODELS SEEM TO BE IN AGREEMENT WITH THIS SCENARIO AS IT
UNFOLDS.
DROPPED BACK TEMPERATURES A FEW DEGREES TUESDAY DUE TO SHOWER THREAT
BUT BOOSTED THEM A COUPLE WEDNESDAY INTO THURSDAY AS SHOWERS BEGIN
TO EXIT THE AREA.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
MID LEVEL DECK DEVELOPED DURING THE NIGHT OVER NORTHERN LOWER
MICHIGAN AND IS HEADED TOWARD ERIE. SHOULD SEE THIS DECK FOR THE
MORNING HOURS UNTIL SOME MID LEVEL DRYING TAKES PLACE TO DISSIPATE
THE CLOUDS. OTHERWISE...HIGH LEVEL SCATTERED CIRRUS WILL AFFECT
THE REGION TODAY AS REGION REMAINS UNDER THE INFLUENCE OF HIGH
PRESSURE. LAKE BREEZE EXPECTED TO DEVELOP AT ERIE AND CLEVELAND
DURING THE DAY AND THEN LAND BREEZE SETS UP. WINDS SHOULD REMAIN
BELOW 10 KNOTS.
.OUTLOOK...NON-VFR CONDITIONS MAY DEVELOP NEAR THUNDERSTORMS MONDAY
AND TUESDAY.
&&
.MARINE...
RELATIVELY QUIET ON THE LAKE THROUGH THE NEXT 5 DAYS. GENERALLY
LOOKING AT WAVES OF 2 FEET OR LESS. STAGNANT LIGHT OR WEAK FLOW WILL
PERSIST THROUGH THE PERIOD.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...REL
SHORT TERM...TK
LONG TERM...LOMBARDY
AVIATION...LOMBARDY
MARINE...LOMBARDY
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1120 PM MDT THU MAY 17 2012
.AVIATION...
A SFC TROUGH WILL REMAIN IN PLACE OVER THE REGION...WITH VARIABLE
WINDS ALONG AND NEAR THE SFC TROUGH. THIS INCLUDES KRAP. ISOLD
SHRA/TS WILL BE POSSIBLE THROUGH DAWN...WITH GUSTY WINDS POSSIBLE
FROM OUTFLOW. A STRONGER UPPER LEVEL IMPULSE WILL TRAVERSE THE
NORTHERN PLAINS FRIDAY AFTERNOON/EVENING...FORCING THE DEEPENING
OF SFC LOW PRESSURE WITH INCREASING CHANCES FOR SHRA/TS IN THE
AFTERNOON. WINDS WILL STRENGTHEN OUT OF THE NW BEHIND THE SFC
TROUGH...WITH GUSTY SSW WINDS TO THE EAST OVER SOUTH CENTRAL SD.
NORTH WINDS WILL BECOME QUITE GUSTY IN THE LEE OF THE BLACK HILLS
FRIDAY EVENING AND OVERNIGHT INTO SATURDAY...WITH GUSTS OF 40 TO
50 KNOTS OR HIGHER NOT OUT OF THE QUESTION.
&&
.PREV DISCUSSION... /ISSUED 752 PM MDT THU MAY 17 2012/
UPDATE...
PERTURBED SW FLOW CONTINUES TO SUPPORT AN ARRAY OF IMPULSES OVER
THE NORTHERN PLAINS AND CENTRAL ROCKIES...WITH EACH DISTURBANCE
SUPPORTING ISOLD/SCT SHRA/TS. STRONGEST LOCAL MID LEVEL FORCING
SEEMS TO BE ASSOCIATED WITH THE A COMPLEX OF TS OVER NORTHERN
CAMPBELL COUNTY...WHICH IS ON TRACK TO SKIRT MUCH OF THE FAR NW
THIS EVENING. HIGH LCL/S WITH STEEP LL/MID LAPSE RATES LOOKS TO
SUPPORT A STRONG GUSTY WIND AND SMALL HAIL THREAT WITH THE
STRONGEST CELLS. ADJUSTED POPS TO ACCOUNT FOR ONGOING
ACTIVITY/TRENDS...WITH EXPANSION OF SLIGHT CHANCE POPS TO COVER
THE FAR SE.
PREV DISCUSSION... /ISSUED 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 BRINGING 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.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...BARBER
LONG TERM...77
AVIATION/UPDATE...JC
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
314 PM CDT FRI MAY 18 2012
.SHORT TERM...
QUIET CONDITIONS EXPECTED THE REMAINDER OF TODAY THOUGH WINDS WILL
REMAIN BREEZY EAST OF THE DRYLINE. DRYLINE HAS PUSHED ALMOST TO THE
27/87 CORRIDOR EARLY THIS AFTERNOON THOUGH BEST CONVERGENCE REMAINS
SOME 60 OR SO MILES EAST ACROSS OUR CWFA. UPPER LEVEL TROUGH AXIS
STRETCHING FROM SRN ID TO NWRN SONORA WILL PIVOT AND BECOME
NEGATIVELY TILTED INTO SATURDAY AS THE BULK OF THE ENERGY ENTERS THE
CENTRAL PLAINS. IN RESPONSE 40-50KT LLJ WILL ASSIST IN ENHANCED
SHALLOW MOISTURE ADVECTION OVERNIGHT AND SATURDAY MORNING ACROSS THE
REGION. MIGHT SEE SOME LOW CLOUDS FORM INVOF THE LLJ IN THE MOIST
SECTOR. DRYLINE SHOULD QUICKLY MIX EASTWARD TO THE ESCARPMENT
/POSSIBLY FURTHER EAST/ ONCE AGAIN THOUGH THIS TIME...WITH THE ADDED
MOISTURE IN PLACE...AND FAVORABLE RR QUADRANT OF JETLET SOUTHEAST OF
THE TROUGH TO OUR NORTHWEST...WE COULD SEE SHOWERS AND THUNDERSTORMS
DEVELOP ALONG/E OF DRYLINE. AT THIS POINT...ACTIVITY LOOKS AS IF IT
WILL BE HIGH BASED WITH CONDITIONAL SUPPORT FOR SEVERE WIND GUSTS
AND LOW END SEVERE HAIL.
&&
.LONG TERM...
EXTENDED FORECAST IS PLAGUED WITH A LINGERING FRONTAL PASSAGE...CHANCES
FOR PRECIP WITH ACCOMPANIED COOLER TEMPS...FOLLOWED BY A RETURN OF
ABOVE SEASONAL NORMS.
UA TROUGH CURRENTLY ACROSS EASTERN NEVADA/WESTERN UTAH WILL EJECT
ENE TO ACROSS THE CENTRAL PLAINS TOMORROW EVENING...WITH ITS
ASSOCIATED COLD FRONT SURGING SOUTH ACROSS THE NORTHERN SOUTH PLAINS
LATE TOMORROW NIGHT/EARLY SUNDAY MORNING. THE SPATIAL AND TEMPORAL
DISTRIBUTION OF THE FROPA IS A BIT QUESTIONABLE AS THE NAM SOLUTION
QUICKLY PUSHES IT SOUTH OF THE CWA BY SUNDAY MORNING...VERSUS
STALLING IT ACROSS THE SOUTHERN ZONES SUNDAY EVENING PER THE GFS.
CONCURRENTLY...A DRYLINE DISPLACED ACROSS THE ROLLING PLAINS WILL BE
QUICKLY SHUNTED WEST OF THE FA THANKS TO THE FRONTAL INTRUSION...BUT
NOT BEFORE FORECAST SOLUTIONS DISPLAY PRECIP DEVELOPING ALONG THE
INTERSECTION OF THE FROPA AND DRYLINE ACROSS WESTERN
OKLAHOMA...EASTERN PANHANDLES AND FAR NERN SOUTH PLAINS LATE TOMORROW
NIGHT/EARLY SUNDAY MORNING. CURRENT THINKING IS THAT BETTER CHANCES
FOR PRECIP WILL EXIST ACROSS THE EASTERN PANHANDLES AND WESTERN
OKLAHOMA NEAREST TO THE BEST SYNOPTIC LIFT. HOWEVER...PROGGED PWATS
OVER 1.00 INCH AND MESOSCALE LIFTING MECHANISMS SUCH AS THE COLD
FRONT AND RETREATING DRYLINE CAN NOT BE OVERLOOKED...AND WILL
THEREFORE MAINTAIN SLIGHT CHANCE POPS ACROSS THE NERN ZONES TOMORROW
NIGHT.
SFC RIDGE NE OF THE REGION WILL INDUCE SFC WINDS TO VEER TO A
NORTHEAST/UPSLOPE WIND COMPONENT THROUGHOUT THE DAY ON SUNDAY...AND
THUS PROMOTE MOISTENING LOW LEVELS /PWATS OVER 1.00 INCH/. NEAR
ZONAL FLOW ALOFT WILL ENSUE...HOWEVER THIS DOES NOT NECESSARILY
EQUATE QUIET WEATHER CONDITIONS GIVEN THE DEPICTION OF THE FROPA PER
THE GFS. AS SUCH...THIS WOULD SUGGEST PRECIP INCREASING IN COVERAGE
FROM EAST TO WEST...WHICH WOULD HAVE A DIRECT EFFECT ON DAYTIME
HIGHS DUE TO THE INCREASED CLOUD COVER. THE NAM SOLUTION IS DRY GIVEN
THE FARTHER SOUTHERN DISPLACEMENT OF THE FRONT...HOWEVER THE ECMWF
HINTS AT PRECIP DEVELOPING ACROSS THE EASTERN AND SOUTHERN ZONES
SUNDAY NIGHT NEAR THE STALLED BOUNDARY. WILL THEREFORE LEAN TOWARDS
A BLEND OF THE GFS AND ECMWF IN REGARD TO THE FROPA BEHAVIOR LEADING
TOWARDS TEMPS IN MID 70S NW TO MID 80S SE...AND MAINTAIN A GRADUAL
INCREASE IN POPS THROUGHOUT THE DAY SUNDAY.
THE COLD FRONTAL BOUNDARY THAT IS STALLED ACROSS THE SOUTHERN ZONES
OR JUST SOUTH OF THE CWA WILL RETREAT NORTH AS A WARM FRONT LATE
SUNDAY NIGHT/EARLY MONDAY MORNING. LONG TERM SOLUTIONS REVEAL
PRECIP ACROSS THE NORTHERN ZONES ON MONDAY ALONG THE RETREATING
FRONT...BUT DRYING CONDITIONS /PWATS DROPPING BELOW 1.00 INCH/ AND
WARMER TEMPS /LOWER 90S/ WILL COMMENCE BY TUESDAY AS UA RIDGING
TRANSLATES EAST ACROSS THE REGION. THEREAFTER...BOTH THE GFS AND
ECMWF SOLUTIONS ARE SIMILAR IN DEPICTING A BROAD UA LOW BECOMING
QUASI-STATIONARY NEAR NORTHWESTERN NEVADA THURSDAY NIGHT/FRIDAY
MORNING. THIS WILL PROMOTE SW FLOW ALOFT...THE RETURN OF THE
SLOSHING DRYLINE AND PERHAPS INCREASING CHANCES FOR PRECIP AS GULF
MOISTURE RETURNS TO THE REGION /THE PREVIOUS MODEL RUNS WERE
DIFFERENT IN REGARD TO THE SYNOPTIC FLOW/. WILL MAINTAIN
MENTIONABLE POPS ONLY ON SATURDAY AND SUNDAY WHERE THE POTENTIAL
FOR STORMS TO APPROACH SEVERE LEVELS EXIST GIVEN SFC BASED CAPE OF
1000-2000 J/KG...AND SILENT POPS THEREAFTER DUE TO FORECAST MODELS
STRUGGLING WITH THE EXTENDED SYNOPTIC PATTERN.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 57 88 51 76 53 / 0 0 10 20 20
TULIA 62 90 55 74 56 / 0 10 10 20 20
PLAINVIEW 64 92 56 75 56 / 0 10 10 20 20
LEVELLAND 64 91 56 79 57 / 0 10 10 20 30
LUBBOCK 64 93 58 79 59 / 0 10 10 20 30
DENVER CITY 63 91 56 82 58 / 0 10 10 20 30
BROWNFIELD 64 93 59 82 59 / 0 10 10 20 30
CHILDRESS 66 96 63 79 63 / 10 20 20 20 30
SPUR 63 96 63 82 61 / 0 20 20 30 30
ASPERMONT 65 93 64 85 65 / 0 10 10 20 30
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
26/29
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
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AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1031 PM CDT SAT MAY 19 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.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...FOR 06Z TAF ISSUANCE. QUIET WX EXPECTED ACRS MOST OF
THE AREA TNGT...THOUGH CONVECTION MAY BRUSH N-C WI OVERNIGHT...AND
BEGIN TO IMPACT THE REST OF THE WRN PART OF THE FCST AREA LATE
TNGT. ANOTHER LOW-END LLWS SITUATION. BEST CHC OF TSRA WL BE IN
CENTRAL WI MID-DAY TOMORROW...AND IN ERN WI TOMORROW DURING THE
MID-LATE AFTN.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...CORRECTED
NWS MILWAUKEE/SULLIVAN WI
1000 PM CDT SAT MAY 19 2012
CORRECTED DUE TO MISSING UPDATE CODING.
.UPDATE...
00Z/20 NAM RUN REMAINING CONSISTENT WITH KEEPING QPF WEST OF CWA
OVERNIGHT...AND FROM MADISON WEST THROUGH 18Z SUNDAY. LATEST RUNS
OF THE HRRR AND RAP ALSO KEEPING CWA DRY OVERNIGHT...SO WILL KEEP
DRY FORECAST GOING FOR TONIGHT.
AS FOR TOMORROW...FIRST LOOK HAS NAM SHOWING BEST LAYER Q-VECTOR
CONVERGENCE STAYING NORTH AND WEST UNTIL LATE AFTERNOON...SHIFTING
EAST OF REGION BY 06Z SUNDAY. USING THE LATEST 00Z NAM RUN...LOCAL
SEVERE WEATHER PROBABILITY OUTPUT SHOWS 60 TO 70 PCT OVER THE
ENTIRE CWA AT 21Z...PEAK HEATING OF THE DAY...THEN DIMINISHING
RAPIDLY BETWEEN 00Z AND 03Z. HOWEVER...MODEL DEW POINTS AGAIN
APPEAR TOO HIGH/66F AT BLUE RIVER AT 18Z...SO PREVIOUS FORECAST
DEW POINTS OF UPPER 50S TO AROUND 60 MAY BE BETTER AND ARE
SUPPORTED BY LOWER DEW POINTS CURRENTLY UPSTREAM ALONG THE
FRONT...WITH THE ONLY 63 TO 65 DEW POINTS BOTTLED UP IN LOUISIANA
AND ARKANSAS. WILL AWAIT FULL MODEL SETS...BUT COULD STILL HAVE
ENOUGH CAPE AND SHEAR FOR AN ISOLATED STORM OR TWO THAT COULD
PRODUCE HAIL AND GUSTY WINDS APPROACHING SEVERE LEVELS DURING
TIME OF MAX HEATING/INSTABILITY SUNDAY AFTERNOON/EARLY EVENING.
&&
.AVIATION/06Z TAFS/...
WILL KEEP LOW-LEVEL WIND SHEAR GOING OVERNIGHT WITH LATEST RAP
SOUNDINGS STILL INDICATING 33 TO 35 KNOT WINDS ABOVE THE NOCTURNAL
INVERSION AROUND 1500 FEET. THREAT ENDS WITH MORNING MIX OUT AS
SURFACE WINDS RAPIDLY INCREASE AND BECOME GUSTY WITHIN 2 HOURS OR
SO OF SUNRISE. VFR CONDITIONS WITH ONLY SCT MID-LEVEL AND BROKEN HIGH
LEVEL CLOUDS OVERNIGHT. LATEST NAM STILL HOLDS OFF ON PCPN AT KMSN
UNTIL AFTER 15Z...REACHING KUES BETWEEN 18Z AND 21Z...AND KMKE AND
KENW AFTER 21Z. PCPN ENDS FROM WEST TO EAST WITH SURFACE TROUGH
PASSAGE...ENDING AT EASTERN TAF SITES BY 06Z MONDAY.
&&
.MARINE...
WINDS WILL STRENGTHEN SUNDAY MORNING AS GRADIENT TIGHTENS AHEAD OF
SURFACE LOW WHICH CROSSES FROM SE MINNESOTA TO NEAR GRB DURING THE
AFTERNOON/EARLY EVENING. HOWEVER THEY APPEAR TO REMAIN BELOW
CRITERIA. WINDS WILL SLACKEN IN THE AFTERNOON WITH THE GRADIENT
RELAXING AS THE LOW PASSES NEARBY...THEN SHIFT WEST WITH PASSAGE
OF COLD FRONT...AND NORTH OVERNIGHT AS LOW MOVES TO THE EAST-
NORTHEAST.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...REM
TONIGHT/SUNDAY AND AVIATION/MARINE...MRC
SUNDAY NIGHT THROUGH SATURDAY...DAVIS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
635 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...TONIGHT AND SUNDAY
635 PM CDT SAT MAY 19 2012
CONVECTION WAS OCCURRING ALONG A COLD FRONT OVER MINNESOTA...WITH
SOUTHERLY WINDS CONTINUING AHEAD OF IT. RADAR WAS INDICATING SOME
LIGHT ECHOES OVER SOUTHEAST MINNESOTA...BUT LOW LEVELS VERY DRY AND
THUS FAR NOTHING MAKING IT TO THE GROUND. MAINLY VFR CONDITIONS
EXPECTED THROUGH THE TAF PERIOD. AS COLD FRONT MOVES EAST
OVERNIGHT...SHOWERS WILL BEGIN TO AFFECT THE TAF SITES BY LATE
EVENING. AT THIS POINT...INSTABILITIES QUITE LOW AND NOT
EXPECTING ANY THUNDER. CANNOT RULE OUT A BRIEF DROP INTO THE
CEILINGS TO MVFR FOR A SHORT PERIOD OF TIME LATER TONIGHT...BUT
VFR CONDITIONS EXPECTED. FRONT PUSHES THROUGH SUNDAY MORNING...WITH
SHOWERS ENDING AT KRST AROUND 15Z AND KLSE AROUND 20Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
253 PM CDT SAT MAY 19 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
558 PM CDT SAT MAY 19 2012
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.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...QUIET WX EXPECTED AGAIN TNGT. DECOUPLING WL AGAIN
RESULT IN APPROACHING LLWS CRITERIA. REMNANTS OF MN CONVECTION
COULD WORK INTO N-C WI LATE. BEST CHC OF TSRA WL BE IN CENTRAL WI
MID-DAY TOMORROW...AND IN ERN WI TOMORROW DURING THE MID-LATE
AFTN.
SKOWRONSKI
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
526 PM CDT FRI MAY 18 2012
UPDATED AVIATION PORTION FOR 00Z 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 00Z TAF ISSUANCE. VFR CONDITIONS EXPECTED
THROUGHOUT. DECOUPLING THIS EVENING WL ALLOW SOME WIND SHEAR TO
DEVELOP...BUT SITN IS MARGINAL FOR INCLUSION OF LLWS IN THE TAFS.
WL KEEP LLWS FOR THE THE WRN TAF SITES...BUT TONE DOWN A BIT FM
PREV FCST.
SKOWRONSKI
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
243 PM CDT FRI MAY 18 2012
.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...VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH AT LEAST
MIDDAY ON SATURDAY. GUSTY SOUTH-SOUTHWEST WINDS WILL CONTINUE
THROUGH EARLY THIS EVENING BEFORE DIMINISHING. BUT LLWS TO DEVELOP
OVER CENTRAL AND NORTH-CENTRAL WISCONSIN TONIGHT. SOUTH WINDS WILL
BECOME GUSTY ONCE AGAIN BY LATE MORNING ON SATURDAY.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/RDM
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
335 AM CDT SUN MAY 20 2012
...UPDATED SYNOPSIS...SHORT TERM AND LONG TERM DISCUSSIONS...
.SYNOPSIS...
ISSUED AT 335 AM CDT SUN MAY 20 2012
WATER VAPOR LOOPS SHOW A WEAK VORT MAX TRAILING THE MAIN SHORTWAVE
TROUGH THAT MOVED OUT OVER THE CENTRAL HIGH PLAINS SUNDAY
AFTERNOON. A SMALL AREA OF LIGHT RAIN SHOWERS WAS MOVING INTO FAR
WEST CENTRAL KANSAS...APPARENTLY BEING FORCED ALONG A BAND OF MID
LEVEL FRONTOGENETIC FORCING. FARTHER WEST...AN UPPER LEVEL RIDGE WAS
BUILDING OVER THE ROCKIES AS EVIDENT IN THE WIDESPREAD 50-70 METER
HEIGHT RISES AT 500 MILLIBARS FROM WASHINGTON STATE TO COLORADO
AND NEW MEXICO. SURFACE HIGH PRESSURE CONTINUED TO NOSE SOUTHWARD
INTO THE CENTRAL HIGH PLAINS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 335 AM CDT SUN MAY 20 2012
THE LATEST NAM AND RUC MODEL GUIDANCE SHOWS THE BAND OF 700 MILLIBAR
FRONTOGENETIC FORCING ACROSS FAR WESTERN KANSAS EARLY THIS MORNING.
THE MODELS MOVE THIS AREA OF FORCING EASTWARD AND WEAKEN IT
THROUGH SUNRISE. GIVEN THE GOING RADAR TRENDS, EXPECT THE
PRECIPITATION TO BE MOVING OUT OF WESTERN KANSAS AND THROUGH
CENTRAL KANSAS BY 12Z AS THE FORCING MOVES EAST AND WEAKENS.
WINDS HAVE BECOME LIGHT AND VARIABLE AS THE BOUNDARY LAYER
DECOUPLED THIS EVENING. SURFACE HIGH PRESSURE WILL BE BUILDING
INTO WESTERN KANSAS THROUGH THIS MORNING. WE SHOULD SEE A PERIOD
OF WINDS GUSTING TO AROUND 20 KNOTS OR SO DEVELOPING AFTER
SUNRISE. WINDS WILL DIMINISH AND SWITCH TO THE EAST/NORTHEAST THIS
AFTERNOON AS THE HIGH PRESSURE MOVES OFF TO THE EAST.
WIDELY SCATTERED THUNDERSTORMS WILL LIKELY DEVELOP OFF THE FRONT
RANGE OF THE ROCKIES THIS AFTERNOON AS SOME LIMITED INSTABILITY
DEVELOPS WITH CAPE VALUES AROUND 500 J/KG OR SO. MODEL SOUNDINGS
ACROSS FAR SOUTHWEST KANSAS ARE MORE STABLE SO EXPECT THAT ANY
THUNDERSTORMS THAT DEVELOP WILL PROBABLY STAY IN EASTERN COLORADO
BEFORE DIMINISHING WITH SUNSET.
SKIES SHOULD BE MOSTLY CLEAR TONIGHT AS UPPER LEVEL RIDGING CONTINUES
TO DEVELOP. LOW TEMPERATURES MAY FALL INTO THE UPPER 40S AROUND HAYS
AND LARNED CLOSER TO THE SURFACE HIGH PRESSURE. FARTHER WEST...LOWS
SHOULD STAY IN THE MID 50S AROUND ELKHART WHERE WINDS WILL STAY UP
A LITTLE MORE TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 335 AM CDT SUN MAY 20 2012
SHORT RANGE MODELS INDICATE A WEAK UPPER LEVEL RIDGE OF HIGH
PRESSURE DEVELOPING ACROSS THE ROCKIES EARLY MONDAY SETTING UP A
NORTHWESTERLY FLOW ALOFT ACROSS THE WESTERN HIGH PLAINS. MEANWHILE,
SURFACE HIGH PRESSURE WILL BE TRACKING EAST OUT OF THE NORTHERN
PLAINS INTO THE UPPER MIDWEST HELPING TO INFLUENCE A SOUTHEASTERLY
UPSLOPE FLOW ACROSS THE WESTERN HIGH PLAINS. AS A RESULT, DIURNALLY
DRIVEN ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ARE EXPECTED TO
DEVELOP JUST LEE OF THE ROCKIES MONDAY AFTERNOON AND EVENING,
POTENTIALLY DRIFTING EASTWARD INTO FAR SOUTHWESTERN KANSAS. WILL
RETAIN THE SLIGHT POPS ACROSS OUR FAR SOUTHWEST DUE TO THE EXPECTED
WEAK FLOW ALOFT COMBINED WITH THE UNCERTAINTY AS TO HOW FAR EAST
ANY DEVELOPING STORMS MAY REACH BEFORE DISSIPATING.
MEDIUM RANGE MODELS SHOW AN UPPER LEVEL TROUGH TRACKING SOUTHEAST
ACROSS THE PACIFIC NORTHWEST INTO THE ROCKY MOUNTAIN REGION TUESDAY
SETTING UP FOR ANOTHER CHANCE FOR PRECIP TO PORTIONS OF CENTRAL AND
WESTERN KANSAS. AS THE SYSTEM APPROACHES, INCREASING FIELDS OF
DIVERGENCE ALOFT WILL DEVELOP DOWNSTREAM OF THE TROUGH AXIS.
ADDITIONALLY, A PREVAILING LOW LEVEL SOUTHEASTERLY UPSLOPE FLOW
ACROSS THE WESTERN HIGH PLAINS WILL HELP WITH INCREASED FORCING AS
WELL AS ADVECT MORE MOISTURE NORTHWARD INTO THE REGION. AS A RESULT,
THE CHANCE FOR A FEW SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS
PORTIONS OF CENTRAL AND WESTERN KANSAS INTO TUESDAY. DRIER
CONDITIONS ARE EXPECTED ACROSS WESTERN KANSAS WEDNESDAY AS A
DEVELOPING SURFACE LOW LEE OF THE ROCKIES STRENGTHENS HELPING TO
DRAW DRIER AIR NORTHEASTWARD INTO SOUTHWEST KANSAS.
TEMPERATURES WILL BE SLIGHTLY WARMER GOING INTO MONDAY AS SURFACE
HIGH PRESSURE DROPS SOUTHEAST OUT OF THE NORTHERN PLAINS INTO THE
MID MISSISSIPPI RIVER VALLEY. THIS WILL HELP KEEP A SOUTHEASTERLY
LOW LEVEL FLOW IN PLACE ACROSS WESTERN KANSAS ALLOWING FOR SOME
MODEST WARM AIR ADVECTION. THE NAM, GFS, AND ECMWF SHOW H85
TEMPERATURES RANGING FROM THE MID TEENS(C) ACROSS CENTRAL KANSAS
TO NEAR 20C ALONG THE COLORADO BORDER. LOOK FOR HIGHS TO BE NEAR
TO JUST ABOVE 80F MONDAY AFTERNOON WITH A FEW UPPER 70S(F) STILL
POSSIBLE IN SOME LOCATIONS...MAINLY IN CENTRAL KANSAS. THE WARMING
TREND WILL CONTINUE INTO TUESDAY AS LEE SIDE TROUGHING STRENGTHENS
ACROSS EASTERN COLORADO. ENHANCED WARM AIR ADVECTION WITHIN A
STRONGER SOUTH TO SOUTHWESTERLY FLOW WILL RAISE H85 TEMPERATURES
UP TO NEAR 20C ACROSS CENTRAL KANSAS TO THE UPPER 20S(C) ACROSS
FAR SOUTHWEST KANSAS. EXPECT HIGHS FROM THE MID TO UPPER 80S(F) IN
CENTRAL KANSAS TUESDAY AFTERNOON TO THE LOWER TO MID 90S(F) IN
EXTREME SOUTHWEST KANSAS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1257 AM CDT SUN MAY 20 2012
WILL SHOW SOME SCATTERED TO BROKEN MID/UPPER LEVEL CLOUDINESS ACROSS
CENTRAL AND SOUTHWEST KANSAS THROUGH THE EARLY MORNING HOURS AS A WEAK
DISTURBANCE MOVES OVER THE AREA. AN ASSOCIATED SMALL AREA OF LIGHT RAIN
SHOWERS OR SPRINKLES WILL ALSO MOVE THROUGH THE AREA. THIS PRECIPITATION
IS VERY LIGHT SO VISIBILITIES SHOULD REMAIN IN THE VFR CATEGORY. NORTHERLY
WINDS MAY BECOME GUSTY FOR A TIME AFTER SUNRISE BUT SHOULD DECREASE
AGAIN AND SWITCH AROUND TO THE NORTHEAST AFTER 18Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 77 55 81 60 / 0 0 10 10
GCK 76 54 81 60 / 0 10 10 10
EHA 76 56 82 60 / 0 10 20 20
LBL 77 57 82 61 / 0 10 20 20
HYS 76 53 81 60 / 0 0 10 10
P28 80 57 80 61 / 0 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GERARD
SHORT TERM...GERARD
LONG TERM...JJOHNSON
AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS WICHITA KS
1155 PM CDT SAT MAY 19 2012
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
LINGERING CONVECTION WILL FESTER OVER SOUTHEAST KS
OVERNIGHT...AFFECTING MAINLY KCNU AND POSSIBLY KICT...AS COLD
FRONT CONTINUES TO SLOWLY ADVANCE SOUTHEAST. CANNOT RULE OUT A FEW
SHOWERS/THUNDERSTORMS OVER FAR SOUTHERN KS SUNDAY ALONG MID-LEVEL
BAROCLINIC ZONE...WHICH COULD FLIRT WITH KICT-KCNU. LEFT OUT OF
TAFS FOR NOW.
ADK
&&
.PREV DISCUSSION... /ISSUED 959 PM CDT SAT MAY 19 2012/
UPDATE...
STRONG/SEVERE STORMS ARE HANGING AROUND A BIT LONGER THAN
PREVIOUSLY EXPECTED...AND ARE REMAINING FAIRLY STOUT FURTHER EAST
THAN PREVIOUSLY THOUGHT...DESPITE SHARPLY DECREASING INSTABILITY
EAST OF THE FLINT HILLS AND A STOUT CAPPING INVERSION PER TOPEKA
AND SPRINGFIELD EVENING SOUNDINGS. ONE POSSIBILITY FOR THE RECENT
70-80 MPH WIND GUST OVER GREENWOOD COUNTY IS EVAPORATIVE COOLING
DUE TO DRY LOW-LEVELS. ACTIVITY OVER SOUTH-CENTRAL KANSAS ALONG
THE OK BORDER IS STILL ABLE TO TAP A MODESTLY UNSTABLE
AIRMASS TO THE SOUTH OF THE COLD FRONT...SO STRONG/SEVERE MAKES
SENSE THERE. OVERALL TREND SHOULD BE FOR A GRADUAL DECREASE IN
THUNDERSTORM INTENSITY...ALTHOUGH COVERAGE COULD STAY UP DUE TO
LOW-LEVEL JET ACTING ON COLD FRONT. WILL CONTINUE SEVERE
THUNDERSTORM WATCH GENERALLY SOUTHEAST OF THE KS TURNPIKE IN
EFFECT UNTIL 4 AM...ALTHOUGH ENVISION OVERNIGHT SHIFT WILL BE ABLE
TO CANCEL EARLY.
ADK
PREV DISCUSSION... /ISSUED 805 PM CDT SAT MAY 19 2012/
UPDATE...
IT APPEARS TORNADO THREAT IS RAPIDLY WANING AS LOW-LEVEL CAPE
DECREASES DUE TO ONSET OF DIURNAL COOLING.
ADDITIONALLY...MAGNITUDE OF SEVERE WEATHER SHOULD GRADUALLY WANE
WITH EASTWARD EXTENT...AS LOW-LEVEL THETA-E AND INSTABILITY DROPS
OFF SHARPLY EAST OF THE FLINT HILLS. HOWEVER...DID END UP
INCLUDING GREENWOOD-ELK-CHAUTAUQUA-COWLEY COUNTIES IN THE SEVERE
THUNDERSTORM WATCH UNTIL 10 PM. SUB-SEVERE SHOWERS/THUNDERSTORMS
COULD CONTINUE REDEVELOPING/FESTERING OVER PORTIONS OF
CENTRAL/SOUTH- CENTRAL KS IN WAKE OF THE SURFACE COLD
FRONT...ALONG ELEVATED FRONTAL SURFACE PUSHING EAST.
ADK
PREV DISCUSSION... /ISSUED 659 PM CDT SAT MAY 19 2012/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
SCATTERED STRONG/SEVERE STORMS ALONG AN EASTWARD ADVANCING COLD
FRONT WILL CONTINUE MOVING EAST/NORTHEAST THIS
EVENING...AFFECTING KSLN-KICT WITHIN THE NEXT FEW HOURS AND
POSSIBLY KHUT. VERY HEAVY RAIN...GUSTY WINDS AND HAIL CAN BE
EXPECTED. THREAT SHOULD PASS KHUT-KICT-KSLN BY 02-03Z OR SO...WITH
THUNDERSTORMS MAYBE NOT EVEN MAKING IT TO KCNU. WILL CONTINUE TO
MONITOR.
ADK
PREV DISCUSSION... /ISSUED 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 LATTER 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 / 60 20 10 0
HUTCHINSON 56 78 54 80 / 60 10 0 0
NEWTON 57 77 53 78 / 60 20 10 0
ELDORADO 59 78 54 79 / 60 20 10 0
WINFIELD-KWLD 61 79 58 80 / 60 30 20 10
RUSSELL 52 77 51 81 / 10 10 0 0
GREAT BEND 53 78 52 81 / 10 10 0 0
SALINA 56 78 51 80 / 60 10 0 0
MCPHERSON 57 77 52 79 / 60 10 0 0
COFFEYVILLE 65 81 59 79 / 40 40 30 10
CHANUTE 64 79 57 78 / 50 40 10 10
IOLA 64 78 57 77 / 50 40 10 10
PARSONS-KPPF 65 80 58 78 / 50 40 20 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
329 AM EDT SUN MAY 20 2012
.SYNOPSIS...
HIGH PRES OVR NRN NEW ENGLAND CONTINUES TO NOSE DOWN THE ERN
SEABOARD TDA. THE ARE TWO AREAS OF LOW PRESSURE - A WEAK SYSTEM
WELL E OF VIRGINIA BEACH AND TROPICAL STORM ALBERTO - OFF THE
SOUTH CAROLINA COAST. LOW PRESSURE WILL GRADUALLY LIFT
NORTHEASTWARD MONDAY THROUGH THE MID-ATLANTIC...AS A FRONT MOVES
IN FROM THE WEST FOR TUESDAY AND WEDNESDAY. HIGH PRESSURE SLOWLY
BUILDS IN FOR THE END OF THE WEEK.
&&
.NEAR TERM /TODAY/...
WX SURE HAS BEEN NICE FOR THE PAST SVRL DAYS...40S DWPTS HV MADE
THINGS VERY COMFORTABLE. TDA SHOULD BE ANOTHER FINE DAY OF
WX...ALTHO DWPTS HV CREPT BACK INTO THE 50S. HIGH PRES WHICH HAS
BEEN RESPONSIBLE FOR THIS HAS DONE A SLOW CRAWL OVR THE PAST 48
HRS FM NY STATE TO CT AND NOW TO NRN NH. TDA A WK AREA OF LOW
PRES HAS FORMED E OF ORF...AND IN A REAL RARITY TS ALBERTO HAS
DVLPD OFF THE S CAROLINA CST. FOR TDA ALL THESE SHOULD DO FOR MID
ATLC IS CONT TO PRODUCE CI. YDA TEMPS REACHED LM80S ACROSS MUCH OF
THE AREA. LK LAST NGT WE`LL BE BEGINNING THE DAY FM A HIGHER TEMP
STARTING PT THAN DURG THE LAST DAYS OF THE WORKWEEK...SO WE CAN
XPCT TO SEE LM80S AGN THIS AFTN.
&&
.SHORT TERM /TONIGHT/...
FOR TNGT MDLS..ESPECIALLY THE NAM...SEEM SOMEWHAT AGGRESSIVE ON
BRINGING RAFL INTO THE RGN IN ASSO W/ THE NRN CSTL LOW (NOT
ALBERTO...WHICH IS RMNG FURTHER S). IT`S INTERESTING TO NOTE THAT
THE HRRR IS SHOWING EVEN NOW A FAIRLY DVLPD SPIRAL BANDING OF PCPN
OFF THE DELMARVA...BUT ON IR STLT IT LOOKS AS IF THERE`S BARELY
EVEN ANY CLD IN ASSO W/ IT. SREF SHOWS THE LOW APRCHG THE CST LN
THIS EVE WHILE WEAKENING ERLY ONSHORE FLOW WL ADVECT SOME MOISTURE
INTO CWA. QUSTN THEN IS HOW FAR W AND HOW MUCH? AND WL ALBERTO
TAKE ENERGY FM THE NRN LOW? I HV CUT BACK ON QPF...AND PUSHED
BACK THE TIMING ABT 6 HRS...PSBLY LGT RA REACHING DC BY 06Z.
WOULDN`T BE SURPRISED IF NO PCPN OCCURS W OF THE BLUE RDG...AND HV
CUT WRN CWA POPS TO LO CHC. BEST CHC FOR RAFL OVRNGT WL LKLY BE LWR
SRN MD.
LOWS IN THE 50S XCPT L60S IN THE CITIES/ALONG THE BAY.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
STACKED LOPRES...MOSTLY UNRELATED TO TROPICAL STORM ALBERTO...WILL CONT WWD
DRIFT INTO MID-ATLC MON. HIGH CHC/LOW LIKELY SHWRS AND ISOLATED
THUNDER FOR MON...WITH DIURNAL PEAK IN CNVCTN. MON NGT PCPN WANES AS
CLOSED LOW OPENS AND IS PULLED NEWD/ABSORBED BY APPROACHING NRN
STREAM ULVL TROF. TROF WILL BE BLOCKED BY STRONG BERMUDA RDGG AND
DRAW STATIONARY TUE...EVOLVING INTO CLOSED LOPRES CNTRD S OF RGN ON
WED. AT SFC...TROF/CDFNT WILL CROSS APLCNS TUE...INDUCING SCT/NUM
SHWRS/TSTMS. TEMPS SHUD BE REGULATED BY XTNSV CLOUD COVER
MON...SUPPRESSING MAXIMA TO L/M70S. TUE SHUD HAVE SOME BREAKS IN
CLOUDS...ALLOWING TEMPS TO REACH AOA 80F MOST RGN...THUS THE BETTER
TSTM CHCS. CONFIDENCE IN AFOREMENTIONED IS LOW...AS GUIDANCE IS NOT
IN AGREEMENT AND ALBERTO IS ESPECIALLY NOT WELL HANDLED BY MODELS
ATTM.
WITH M/ULVL LOPRES S/W OF RGN TUE NGT/WED...SFC TROF AXIS WILL
MEANDER THRU CWA AND GRADUALLY WASH OUT...WITH PLENTY MOISTURE IN
PLACE...CHC POPS WARRANTED. GUIDANCE SUGGESTS THAT ANOTHER NRN
BRANCH TROF WILL BCM DOMINATE ACRS PLAINS THU/FRI...ALLOWING SWLY
FLOW TO ESTABLISH ACRS ERN CONUS. WITH THIS...BERMUDA RIDGE WOULD
BUILD INTO ERN CONUS...TRIGGERING DRIER/WARMER CONDS FOR MID-ATLC
FOR WKS END. STILL...LLVL MOISTURE WILL BE DECENT...SO ISOLATED/SCT
MAINLY DIURNAL CNVCTN CANT BE RULED OUT THRU XTDD FCST.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
VFR CONDS TDA. CLDS XPCTD TO BEGIN TO LOWER TNGT...W/ CIGS PSBLY
DROPPING INTO THE MVFR RANGE LATE THIS EVE. LGT RA PSBL OVRNGT BUT
NOT XPCTD TO CAUSE A REDUCTION TO VSBY.
SCT/NUM SHWRS/PSBLY TSTMS WILL IMPACT TERMINALS MON THRU WED.
HIGHLY UNCERTAIN AS TO EXTENT OF PREVAILING FLIGHT
RESTRICTIONS...BUT AT LEAST PERIODS OF SUB-VFR CIGS/VBSYS APPEAR
PLAUSIBLE WITH MOIST ELY FLOW IN PLACE. POPS GRADUALLY DIMINISH FOR
SECOND HALF OF WEEK...AS HIPRES BUILDS IN.
&&
.MARINE...
WINDS HV BEEN BLO SCA LVLS IN EVEN OUR LWR PTMC/BAY..SO HV PUSHED
THE START TIME OF THE SCA TO 8 AM. AS OFFSHORE LOW MOVES CLOSER TO
THE CST XPCT TO SEE MORE 20 KT NRLY GUSTS TDA FM S CHES BAY OF
SANDY PT AND TDL PTMC E OF COBB ISLAND.
NELY FLOW CONTS MON/TUE. GUSTS ON MON MAY APPROACH SCA
THRESHOLD...BUT CONFIDENCE TO LOW ATTM FOR EXTENSION OF HEADLINES.
LOPRES RMNS IN VICINITY THRU MIDWK...WITH SCT/NUM SHWRS/TSTMS XPCD.
SFC TROF/CDFNT APPROACHES TUE NGT/WED...WITH HIPRES SLOWLY BUILDING
IN THEREAFTER.
&&
.TIDES/COASTAL FLOODING...
WITH PROLONGED ELY FLOW AND LWRG PRESSURE ACRS CHESAPEAKE BAY...
MINOR COASTAL FLOODING LOOKS LIKELY WITH MON MRNGS HIGH TIDE.
FAVORABLE FLOW WILL CONT MON INTO TUE...SO ADDITIONAL COASTAL
FLOODING OF SENSITIVE LOCATIONS IS POSSIBLE AGAIN DURING HIGH
TIDES THIS PERIOD.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 6 AM EDT MONDAY
FOR ANZ532>534-537-540>543.
&&
$$
PRODUCTS...WOODY!/SBK
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
423 AM CDT SUN MAY 20 2012
.DISCUSSION...
RAP H5 ANALYSIS ALONG WITH WATER VAPOR IMAGERY SHOWING NEG TILTED
AND FAIRLY STRONG SHORTWAVE MOVING INTO SRN MN THIS MORNING...THAT
IS FLANKED BY FAIRLY ROBUST RIDGING OVER THE ERN GREAT LAKES AND A
WEAK RIDGE NOW MOVING ACROSS THE ROCKIES. A STRONG UPPER JET AND
DEEP UPPER LOW CAN BE SEEN ACROSS THE NRN PAC THAT IS ON ITS WAY
TOWARD WRN CANADA. AT THE SFC...A COUPLE OF COLD FRONTS WERE
ANALYZED ACROSS THE AREA THIS MORNING. THE MAIN COLD FRONT AT 330
AM STRETCHED FROM NEAR ALBERT LEA UP TO THE ASHLAND...WI
AREA...WITH A SECONDARY COLD FRONT SPLAYED OUT ACROSS MN FROM NEAR
DULUTH TO FARGO. ALONG THE PRIMARY FRONT...THERE IS A SFC
CIRCULATION NEAR ROCHESTER. TO THE WEST OF ALL OF THIS...A
SPRAWLING AREA OF HIGH PRESSURE SITS ON OUR DOORSTEP ACROSS THE
NORTHERN PLAINS.
UPPER LOW MOVING INTO SRN MN WILL BE OVER THE U.P. OF MICH BY
TONIGHT AS IT SLOWLY DE-AMPLIFIES AS IT RUNS INTO THE ERN RIDGE.
UPPER RIDGE CURRENTLY OVER THE ROCKIES WILL SLIP ACROSS THE AREA
MON/TUE AS THE UPPER LOW CURRENTLY IN THE NRN PAC MOVES TO THE BC
COAST AS SIGNIFICANT TROUGH SETS UP OVER THE NRN ROCKIES. THIS
GENERAL TROUGH/RIDGE PATTERN WILL BASICALLY REMAIN IN PLACE INTO
THE HOLIDAY WEEKEND...THOUGH BECOME CONSIDERABLY MORE
AMPLIFIED...WITH H5 HEIGHTS IN SUBTROPICAL RIDGE OVER THE OHIO
VALLEY PEGGED TO RISE ABOVE 590 DM.
AT THE SFC...COLD FRONT LOOKS TO CLEAR THE ERN MPX CWA AROUND
18Z...WITH THE SFC LOW TRACKING FROM RST UP THROUGH EAU. HIGH
PRESSURE WILL QUICKLY MOVE ACROSS THE AREA MONDAY...WITH A STRONG
LEE SIDE LOW EXPECTED TO DEVELOP OVER WRN NODAK TUESDAY. FRONTAL
FEATURE WITH THIS LOW STILL ON TRACK TO MOVE INTO WRN MN
WED...THEN STALL OUT THU NIGHT AS IT RUNS INTO THE AMPLIFYING
RIDGE TO THE SOUTH AND EAST. THE GFS/ECMWF SHOW THIS FRONT HANGING
OUT NEAR THE MPX AREA AS A WARM/STATIONARY FRONT THROUGH THE
WEEKEND...WITH NO STRONG KICKER SYSTEM INDICATED UNTIL MEMORIAL
DAY AT THE EARLIEST.
FOR TODAY THE MAIN ISSUES REVOLVE AROUND MOVING POPS OUT OF THE
AREA...HOW MUCH IF AT ALL DO TEMPS WARM UP OUTSIDE OF WRN MN...AND
HOW STRONG WILL THE WINDS BE THIS MORNING. FOR POPS...THE RAP
SHOWS THE DEFORMATION BAND OF PRECIP FOLLOWING JUST W/NW OF THE
SFC LOW. USED A BLEND OF THE HRRR/GEM/NAM TO CRAWL PRECIP ACROSS
THE AREA...WITH MOST PRECIP OUT OF MN BY 18Z...WITH RAIN CLEARING
EAU/LADYSMITH AROUND 21Z. FOR TEMPS...CONTINUED NORTH
WINDS...COMBINED WITH RAINFALL BEHIND THE COLD FRONT HAS STEADILY
BEAT TEMPERATURES BACK INTO THE 50S ACROSS THE MN PORTION OF THE
CWA...WITH 40S NOT TOO FAR AWAY. GIVEN PREFERENCE FOR HANDLING OF
PRECIP THIS MORNING BY THE GEM/NAM...USED THESE MODELS FOR HIGHS
TODAY...WHICH ENDED UP BEING FAIRLY AGGRESSIVE ON THE COLD SIDE OF
THINGS...WITH HIGHS ONLY AROUND 60 UP THE I-35 CORRIDOR. THIS COULD
BUST IN A BIG WAY IF WE CLEAR OUT FOR A COUPLE OF HOURS THIS
AFTERNOON...BUT CLEARING DOES NOT LOOK TO GET TO THE 35 CORRIDOR
SOON ENOUGH TO ALLOW MUCH OF AN IMPROVEMENT IN TEMPS TODAY. FOR
WRN WI...HIGHS WILL BE ACHIEVED BY 18Z...WITH FALLING TEMPS
EXPECTED THROUGH THE AFTERNOON. AS FOR WINDS...HAVE SEEN SOME 40
TO 50 MPH WINDS GUSTS OVERNIGHT IN CENTRAL MN. THOUGH NOT
EXPECTING ANYTHING LIKE THAT TODAY...THE HRRR DOES SHOW A FAIRLY
TIGHT PRESSURE GRADIENT DEVELOPING ON THE WRN EDGE OF THE SFC LOW
WORKING THROUGH SE MN RIGHT NOW. THE HRRR HAS BEEN DOING PRETTY
GOOD AT PICKING UP THE STRONGER WINDS THROUGH THE NIGHT...SO
LEANED HEAVILY ON IT FOR WINDS THIS MORNING...WITH SOME 20-25 MPH
SUSTAINED NORTH WINDS ACROSS ERN MN THROUGH THE MORNING.
TONIGHT...SFC RIDGE OVER THE HIGHS PLAINS WILL MOVE
OVERHEAD...WITH CLEAR SKIES...CALM WINDS...AND A LOW STARTING
POINT WITH TEMPS THIS EVENING ALL CONSPIRING FOR A RATHER COOL
MORNING ON MONDAY...WITH 40S EXPECTED AND A FEW LOWS IN THE 30S
NOT OUT OF THE QUESTION ACROSS CENTRAL MN. MONDAY WILL BE VERY
PLEASANT...WITH ONLY REAL QUESTION BEING HOW LOW DO DEWPS GO IN
THE AFTERNOON. SOUNDINGS CERTAINLY INDICATE STRONG POTENTIAL FOR
SOME GOOD MIXING OF DRIER AIR TO THE SFC AND FAVORED DEWPS MONDAY
TOWARD THE MUCH DRIER MET.
FOR MONDAY NIGHT...STRONG WAA WILL BE COMING IN ALOFT OUT AHEAD OF
THE SYSTEM DEVELOPING OVER THE WRN DAKOTAS. 20.00 GFS GENERATES
SOME ELEVATED THUNDERSTORMS IN WRN MN MON NIGHT IN THIS WAA...BUT
QUICK LOOK AT SOUNDINGS AND RH HEIGHT PROFILES SHOWS ATMO BELOW
10K FT BEING QUITE DRY...SO KEPT THE FORECAST DRY WITH THE
EXPECTATION OF ANOTHER GOOD ROUND OF ACCUS/VIRGA BREAKING OUT. OF
COURSE WITH THAT WAA...A SIGNIFICANT WARM TONGUE AT H85 IS
FORECAST BY ALL MODELS TO COME INTO WRN MN...WITH TEMPS BETWEEN 16
AND 18C NOTED. LAST WEEK THIS RESULTED IN HIGHS IN THE 90S AND
THERE IS GUIDANCE SHOWING PLACES LIKE MADISON GETTING BACK INTO
THE 90S TUESDAY. HOWEVER...THE WARM FRONT SHOULD STAY OFF TO OUR
SW...SO NOT FEELING CONFIDENT IN 90S OCCURRING AGAIN...BUT DID BUMP
WRN MN UP INTO THE MID/UPPER 80S.
AFTER THAT...WHAT LOOKS LIKE A GOOD BET IS ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS WED AFTERNOON INTO THU AS ANOTHER COLD
FRONT MOVES IN. THERE ARE TIMING DIFFERENCES WITH THIS
FRONT...WITH THE GFS SHOWING MORE WED/WED NIGHT WHILE THE ECMWF IS
MORE WED NIGHT/THU. EITHER WAY...DOES LOOK LIKE ANOTHER GOOD SHOT
AT SOME HEALTHY RAINS AS THE FRONT STALLS OUT OVER/NEAR MN
THURSDAY. BEYOND THURSDAY...CONFIDENCE DECREASES QUITE A BIT ON
THE FORECAST AS THE GFS/ECMWF DIFFER ON WHERE TO PLACE THE
STATIONARY/WARM FRONT FRIDAY RIGHT THROUGH MEMORIAL DAY. GIVEN THE
STRENGTHENING RIDGE TO THE SOUTH AND EAST OVER NEXT WEEKEND...THE
FRONT COULD CERTAINLY BE A BREEDING GROUND FOR SEVERAL ROUNDS OF
THUNDERSTORMS AS MOISTURE RIDES UP OVER IT. IF WE EVER END UP ON
THE SOUTH END OF THE FRONT NEXT WEEKEND...RECORD TEMPS CERTAINLY
LOOK LIKE A POSSIBILITY AS H85 TEMPS ARE PROGGED TO GET UP INTO
THE MID/UPPER 20S C OVER THE CENTRAL PLAINS. THE 20.00
ECMWF/GFS...BOTH SHOW THIS FRONT WELL SOUTH OF THE AREA
FRIDAY...WITH IT SLOWLY LIFTING TO NORTH OF THE MPX AREA BY
SUNDAY.
&&
.AVIATION.../06Z TAF ISSUANCE/
THE MAIN AVIATION CONCERN REMAINS THE THREAT OF THUNDERSTORMS
THROUGH SUNDAY MORNING. MESOSCALE CONVECTIVE COMPLEX WAS CENTERED
OVER SOUTHERN MN. THE BACK OF THE COMPLEX EXTENDS OVER EASTERN
SOUTH DAKOTA AND SOUTHWEST IOWA AT THIS TIME. SYSTEM WILL CONTINUE
TO ADVANCE NORTHEAST OVERNIGHT WITH SHOWERS AND THUNDERSTORMS
CONTINUING OVER MUCH OF THE FORECAST AREA. CEILINGS/VISIBILITIES
LOWER TO IFR CONDITIONS IN HEAVY RAIN. SOME SMALL HAIL IS ALSO
POSSIBLE. CONDITIONS WILL BEGIN TO IMPROVE FROM WEST TO EAST
TOWARD DAYBREAK SUNDAY IN WESTERN MN AND DURING THE AFTERNOON
SUNDAY OVER IN WESTERN WISCONSIN. EXPECT CONDS TO IMPROVE TO VFR
BEFORE NOON SUNDAY IN THE KAXN AREA...AND NOT IN THE KEAU AREA
UNTIL AFTER 300 PM. NORTH-NORTHWEST WINDS WILL CONTINUE TO USHER
IN DRIER AIR...ESPECIALLY DURING THE DAY ON SUNDAY.
KMSP...LARGE CLUSTER OF SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
LIFT OVER THE AREA OVERNIGHT. EXPECT OCCASIONAL IFR WEATHER
CONDITIONS IN HEAVY RAIN AND THUNDERSTORMS. CONDITIONS WILL BEGIN
TO IMPROVE SUNDAY AFTERNOON AS DRIER AIR FILTER OVER THE AREA. SOME
PATCHY OR AREAS OF FOG DEVELOPING IN LOW LYING AREAS SUNDAY NIGHT.
OUTLOOK...
SUN NIGHT AND MONDAY MORNING...PATCHY AREAS OF FOG.
MON-TUE...VFR.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/JVM
AREA FORECAST DISCUSSION
NWS HASTINGS NE
440 AM CDT SUN MAY 20 2012
.SHORT TERM...THROUGH TUESDAY NIGHT. OFFICIALLY...THE FORECAST
REMAINS DRY THROUGH THESE 72 HOURS. HOWEVER...THIS WILL NEED
WATCHED CLOSELY AS THERE ARE AT LEAST A FEW OPPORTUNITIES FOR
THUNDERSTORMS TO POTENTIALLY SNEAK INTO THE FORECAST. OF HIGHER
CONFIDENCE IS POSSIBLE ADVISORY-CRITERIA WINDS ON TUESDAY.
08Z OBJECTIVE SURFACE ANALYSIS PLACES THE CWA BETWEEN A 1010MB LOW
OVER WESTERN IA...AND A 1021MB HIGH STRETCHED NORTH-SOUTH ACROSS
THE PANHANDLE INTO EASTERN CO. AS A RESULT...BREEZES EARLY THIS
MORNING ARE LARGELY FROM THE WEST-NORTHWEST AREA WIDE...BUT
RANGING FROM VERY LIGHT IN THE FAR WESTERN COUNTIES...TO GUSTS
STILL AROUND 20 MPH IN THE EAST WHERE THE GRADIENT REMAINS
TIGHTEST. WATER VAPOR IMAGERY CLEARLY DEPICTS THE DEPARTING
SHORTWAVE RESPONSIBLE FOR YESTERDAY/S ROUND OF SEVERE WEATHER NOW
OVER NORTHEAST NEB...WITH BROAD QUASI-ZONAL FLOW ALOFT EXTENDING
BACK UPSTREAM TO THE EASTERN PACIFIC. RADAR AND 11-3.9 MICRON
SATELLITE IMAGERY CONFIRMS A STUBBORN AREA OF LINGERING LIGHT RAIN
THAT HAS FINALLY PUSHED OUT OF THE NORTHEASTERN CWA...IN ASSOCIATION
WITH THE PARENT AREA OF MID LEVEL CONVERGENCE/SATURATION ON THE
BACKSIDE OF THE EXITING SHORTWAVE. MEANWHILE...OFF TO THE SOUTH A
VERY NARROW BAND OF LIGHT RAIN/SPRINKLES IS MAKING ITS WAY ACROSS
PARTS OF CENTRAL KS...LIKELY DUE TO SOME SUBTLE MID LEVEL
FRONTOGENESIS IN THE ENTRANCE REGION OF A MID-UPPER JET STREAK
PULLING ACROSS NORTHERN KS/SOUTHEAST NEB.
FOLLOWING THE 05Z HRRR REFLECTIVITY CLOSELY...ALONG WITH LATEST
RADAR TRENDS...LOOKS LIKE ANY SPRINKLES IN NEB ZONES SHOULD
PRETTY MUCH BE GONE BY SUNRISE...SO WILL NOT CARRY A PRE-FIRST
PERIOD ZONE ISSUANCE TO COVER IT. AS FOR THE KS SPRINKLES...NOT
EXPECTING THESE TO BE AN ISSUE PAST SUNRISE EITHER...BUT WILL
CARRY A SLIGHT CHANCE SPRINKLE MENTION ACROSS THE FAR SOUTHERN CWA
THROUGH 12Z JUST IN CASE SOMETHING SNEAKS IN. OTHERWISE...A DRY
AND SEASONABLY PLEASANT DAY IS IN STORE. ALOFT...THE DEPARTING
SHORTWAVE AXIS WILL BE WELL UP INTO WESTERN WI BY 00Z...WITH
BROAD...MODESTLY AMPLIFIED RIDGING EXTENDING FROM THE WEST COAST
TO CENTRAL PLAINS IN ITS WAKE. AT THE SURFACE...A RIDGE AXIS WILL
GRADUALLY PASS ACROSS THE CWA THROUGH THE DAY...TRANSITIONING
WINDS FROM NORTHERLY THROUGH MUCH OF THE DAY TO MORE EASTERLY BY
DAY/S END. WITH THIS CENTER OF THIS HIGH TO THE NORTH OF THE AREA
THIS MORNING...THERE SHOULD BE AN INCREASE IN WIND SPEEDS MOST
AREAS AS BOUNDARY LAYER MIXING COMMENCES...WITH SUSTAINED SPEEDS
EASILY 10-15 MPH FOR SEVERAL HOURS...BEFORE SUBSIDING A BIT DURING
THE AFTERNOON. ALTHOUGH COULD SEE SOME LINGERING CLOUDS THIS
MORNING...AND MAYBE EVEN SOME DAYTIME FAIR WEATHER CUMULUS
DEVELOPMENT MAINLY IN EASTERN ZONES...THE CWA AS A WHOLE SHOULD
AVERAGE MOSTLY SUNNY TODAY. AS A RESULT...ANTICIPATE A FAIRLY
EFFICIENT WARM UP...AND KEPT HIGHS SIMILAR TO PREVIOUS
FORECAST...AND FAVORING THE WARMER MET GUIDANCE/RAW NAM SOLUTION
VERSUS COOLER MAV/GFS. THUS HAVE THE MAJORITY OF THE CWA REACHING
THE 72-76 RANGE.
TONIGHT...THE BROAD WESTERN TO CENTRAL CONUS RIDGE AMPLIFIES A
BIT...WITH MODEST MID LEVEL HEIGHT RISES OVER THE CENTRAL PLAINS
AS THE UPPER LEVEL FLOW BECOMES MORE NORTHERLY VERSUS WESTERLY
AROUND THE EASTERN PERIPHERY OF THE RIDGE. ALTHOUGH HAVE LEFT ALL
THUNDERSTORM MENTION OUT OF THE FORECAST FOR NOW...WILL HAVE TO KEEP
A CLOSE EYE ON FAR NORTHWEST ZONES AFTER MIDNIGHT AND ESPECIALLY
TOWARD SUNRISE...AS BOTH THE NAM/GFS ADVERTISE MODEST ELEVATED
THETA-E ADVECTION EVIDENT AT 700MB PUSHING EAST OUT OF WESTERN
NEB...ALONG WITH MAYBE UP TO A FEW HUNDRED J/KG MUCAPE ROOTED IN
THE 850-700MB LAYER. BOTH OF THESE MODELS KEEP CONVECTIVE QPF AT
LEAST SLIGHTLY NORTHWEST OF THE CWA OVER THE SANDHILLS...AND THE
00Z 4KM WRF-NMM SHOWS LITTLE HINT OF DEVELOPING CONVECTION...BUT
THIS WILL NEED CLOSELY WATCHED AS THIS KIND OF FORCING OFTEN LEADS
TO CLASSIC SUNRISE SURPRISE SHOWERS/WEAK STORMS. FOR LOW TEMPS
TONIGHT...WITH GENERALLY LIGHT EAST-SOUTHEAST BREEZES AND MOSTLY
CLEAR SKIES...OPTED TO LOWER LOWS 1-3 DEGREES FROM PREVIOUS
FORECAST...WITH MOST AREAS BETWEEN 44-48.
MONDAY...RIDGING WILL CONTINUE TO DOMINATE THE MID/UPPER
LEVELS...WITH THE AXIS GENERALLY ALIGNED ALONG THE ROCKIES...AND
CONTINUED NORTH-NORTHWEST FLOW ALOFT OVER THE CENTRAL PLAINS. AS
THE SURFACE RIDGE AXIS DEPARTS FARTHER EAST AND MODEST PRESSURE
FALLS OCCUR OVER THE HIGH PLAINS...SOUTHERLY WINDS WILL BECOME
ESTABLISHED...AND UPPED SUSTAINED SPEEDS SLIGHTLY WITH MOST OF THE
CWA SOLIDLY INTO THE 15-20 MPH RANGE MUCH OF THE DAY. DESPITE
MODEST LOW LEVEL MOISTURE RETURN WITH SURFACE DEWPOINTS POSSIBLY
APPROACHING 50 ACROSS THE WESTERN CWA...THE PRIMARY LOW LEVEL
INSTABILITY AXIS SHOULD SET UP AT LEAST 1-2 COUNTIES WEST OF THE
CWA DURING THE AFTERNOON...WITH THE NAM KEEPING ANY LATE AFTERNOON
CONVECTION SAFELY NORTHWEST OF THE AREA ACROSS THE SANDHILLS.
ASSUMING THAT NO SHOWERS/WEAK STORMS DO IN FACT DEVELOP EARLY IN
THE MORNING AS DISCUSSED ABOVE...HAVE FAIRLY HIGH CONFIDENCE IN
LEAVING STORMS OUT THROUGH THE AFTERNOON HOURS...DESPITE SPC
ASSIGNING A GENERAL THUNDER AREA TO MUCH OF THE WESTERN CWA ON THE
DAY2 OUTLOOK. WITH SOUTHERLY FLOW AND AFTERNOON MIXING TO AROUND
800MB PER NAM SOUNDINGS...KEPT HIGH TEMPS SIMILAR TO PREVIOUS
FORECAST...AND GENERALLY 2-4 DEGREES ABOVE MET/MAV GUIDANCE
CONSENSUS...WITH MOST AREAS 79-82.
MONDAY NIGHT...THE MID/UPPER RIDGE AXIS BECOMES MORE POSITIVELY
TILTED AND EXTENDS DIRECTLY THROUGH THE CENTRAL PLAINS...AS THE
RIDGE STARTS ITS EASTWARD PUSH IN RESPONSE TO AN INCOMING
SHORTWAVE AND ASSOCIATED UPPER JET STREAK MOVING INTO THE PACIFIC
NORTHWEST. ASSUMING THAT NO SANDHILLS CONVECTION SNEAKS INTO THE
CWA DURING THE EVENING...WILL STAY THE COURSE WITH A STORM-FREE
FORECAST THROUGH THE NIGHT...ALTHOUGH THIS WILL ALSO BEAR WATCHING
AS BOTH THE NAM/GFS ADVERTISE A BATCH OF ELEVATED INSTABILITY ON
THE ORDER OF 500-1000 J/KG SLIDING EAST OVER THE CWA DURING THE
NIGHT. THINKING AT THIS POINT IS THAT THESE PARCELS SHOULD REMAIN
CAPPED IN THE PRESENCE OF VERY LITTLE UPPER FORCING...WITH BETTER
CONVERGENCE ALONG THE NOSE OF THE LOW LEVEL JET AIMED MORE INTO
THE OAX CWA TOWARD THE MO RIVER...WHERE THE NAM ACTUALLY DOES
DEVELOP SOME CONVECTIVE QPF. CERTAINLY CANNOT COMPLETELY RULE OUT
A FEW SHOWERS/STORMS FLARING UP AND LATER SHIFTS MAY HAVE TO
CONSIDER ADDING A SLIGHT POP SOMEWHERE.
TUESDAY...INSTABILITY INCREASES FURTHER...AS SURFACE DEWPOINTS
CLIMB BACK INTO THE LOW-MID 50S...BUT WITH INCOMING NORTHWEST
CONUS SHORTWAVE REMAINING TO THE WEST...THIS SHOULD BE NOTHING
MORE THAN A WARM AND RATHER WINDY DAY...WITH NEAR-SURFACE PARCELS
CAPPED OFF AS SUGGESTED BY 700MB TEMPS INTO THE 11-13C RANGE. ANY
LATE AFTERNOON STORMS THAT MIGHT MANAGE TO DEVELOP IN THE REGION
SHOULD FOCUS WEST OF THE CWA NEARER THE PRIMARY SYNOPTIC DRYLINE.
AS A RESULT...EXPECT THE BIG STORY TUESDAY TO BE STRONG SOUTHERLY
WINDS...AS BOTH THE NAM/GFS DEEPEN A 989-992MB LOW OVER THE HIGH
PLAINS OVER THE COURSE OF THE DAY. THE RESULTANT STRENGTHENING
PRESSURE GRADIENT...ALONG WITH MIXING TO AT LEAST 750MB MOST
AREAS...SHOULD REALLY GET SOUTHERLY WINDS GOING. PREVIOUS FORECAST
ALREADY HAD PARTS OF THE AREA REACHING ADVISORY CRITERIA OF
SUSTAINED 30 MPH...AND GENERALLY KEPT THIS THEME INTACT...WITH THE
HIGHEST SPEEDS FOCUSED ACROSS THE WESTERN 1/2 OF THE CWA. WITH
THIS STILL BEING 5 PERIODS OUT...WAY TOO EARLY FOR A
HEADLINE...BUT WILL CONTINUE TO HIGHLIGHT IN THE HAZARDOUS WEATHER
OUTLOOK. EXPECTING MINIMAL CLOUD COVER...THIS SHOULD BE A CLASSIC
BIG WARM UP...DECENT DEWPOINT MIX-DOWN KIND OF DAY...AND HAVE
DEWPOINTS FALLING A BIT IN THE AFTERNOON...ESPECIALLY WEST. TEMP
WISE...NUDGED UP HIGHS 2-3 DEGREES FROM PREVIOUS FORECAST MOST
AREAS...AIMING FOR 89-92 MOST AREAS...AND EVEN MID 90S SOUTHWEST.
ALTHOUGH THIS IS SEVERAL DEGREES ABOVE MET/MAV GUIDANCE
CONSENSUS...IT IS MORE IN LINE WITH RAW NAM TEMPS...AND DAYS LIKE
THIS HAVE PROVEN SEVERAL TIMES IN THE PAST FEW WEEKS THAT WARMER
IS THE WAY TO GO.
TUESDAY NIGHT...YET AGAIN KEPT THE AREA FREE OF STORM
MENTION...DESPITE THE GFS TRYING TO SNEAK SOME ACTIVITY INTO
NORTHEAST ZONES AFTER MIDNIGHT. DESPITE INCREASING FORCING FROM
THE INCOMING SHORTWAVE...MOST OF THIS ENERGY WILL REMAIN BACK OVER
THE NORTHERN ROCKIES/NORTHERN PLAINS...AND BESIDES BOTH THE
NAM/GFS ADVERTISE A CONSIDERABLE CAPPING INVERSION WITH A 700MB
THERMAL RIDGE OF 13C+ SETTING UP OVER THE CWA DURING THE NIGHT.
NOT SURPRISINGLY...MODEL CONSENSUS IS TO FOCUS CONVECTION NORTH OF
THE CWA THROUGH THE NIGHT...NEAR AND JUST BEHIND AN INCOMING
SURFACE COLD FRONT AND IN AREA OF SLIGHTLY COOLER MID LEVEL TEMPS.
WILL HAVE TO IRON OUT SOME DETAILS REGARDING THE SPEED OF THIS
INCOMING COLD FRONT HOWEVER...AS BY 12Z WEDNESDAY THE NAM ALREADY
HAS THE FRONT INTO THE WESTERN CWA...WHILE THE ECMWF STILL HAS IT
BACK IN WESTERN NEB. IF ANY STORMS DO MANAGE TO DEVELOP INTO THE
NORTHERN CWA DURING THE NIGHT...STRONG TO SEVERE IS CERTAINLY
POSSIBLE...BUT CONFIDENCE STILL REMAINS LOW ENOUGH REGARDING
STORM DEVELOPMENT TO KEEP POPS BELOW THE 20 PERCENT SLIGHT CHANCE
THRESHOLD.
.LONG TERM...TARTING 12Z WEDNESDAY. GUIDANCE FROM THE OPERATIONAL
GFS AND EC SUGGEST A MID LEVEL SHORT WAVE...PERHAPS A CLOSED LOW
PER THE GFS...WILL PUSH ACROSS THE NORTHERN PLAINS AND SOUTH
CENTRAL CANADA WEDNESDAY AND THURSDAY. AN ASSOCIATED SURFACE LOW
IS ALSO EXPECTED TO PUSH EAST ACROSS THE NORTHERN PLAINS AND SOUTH
CENTRAL CANADA THUS ALLOWING A LOW LEVEL BAROCLINIC ZONE TO PUSH
ACROSS OUR AREA DURING THE DAY WEDNESDAY. SURFACE RIDGING IS THEN
EXPECTED TO INFILTRATE THE CENTRAL PLAINS LATE WEDNESDAY THROUGH
EARLY FRIDAY BEFORE LOW LEVEL RETURN FLOW IS REALIZED ACROSS OUR
AREA LATE FRIDAY INTO SATURDAY.
THE OPERATIONAL GFS AND EC BOTH CONTINUE TO INDICATE CONVECTION
ALONG THE LOW LEVEL BAROCLINIC ZONE WEDNESDAY AFTERNOON AND EVENING.
THE OPERATIONAL GFS IS BECOMING SOMEWHAT MORE PROGRESSIVE AND NOW
SUGGESTS CONVECTION WILL FIRE EAST OF OUR CWA WELL AFTER THE LOW
LEVEL BAROCLINIC ZONE HAS CLEARED OUR AREA. THE EC ON THE OTHER HAND
SUGGESTS A SLIGHTLY SLOWER FROPA WITH CONVECTION POSSIBLE ALONG THE
EASTERN HALF OF OUR CWA LATE WEDNESDAY AFTERNOON INTO WEDNESDAY
EVENING. WITH 0-1KM MLCAPE VALUES PERHAPS APPROACHING 1500J/KG AND
DEEP LAYER BULK SHEAR VALUES IN THE NEIGHBORHOOD OF 40KTS...LARGE
HAIL AND PERHAPS STRONG WINDS CANNOT BE RULED OUT SHOULD
CONVECTION BE REALIZED OVER OUR AREA ALONG THE LOW LEVEL BAROCLINIC
ZONE WEDNESDAY. OPTED TO PLAY IT SAFE SINCE THE EC CONTINUES TO
SUGGEST THIS POSSIBILITY AND KEPT CONVECTION IN THE FORECAST ACROSS
THE EASTERN HALF OF THE CWA...WITH A SEVERE MENTION ALSO IN THE HWO
FOR LATE WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING.
MID AND UPPER LEVEL JET ENERGY IS EXPECTED TO PUSH OVERHEAD
THE CENTRAL PLAINS LATE WEDNESDAY...WITH THE LEFT-FRONT QUAD OF A
60-70KT MID LEVEL JET STREAK EXPECTED TO SET UP SHOP OVER OUR AREA
WEDNESDAY NIGHT INTO THURSDAY MORNING. AN INDIRECT THERMAL
CIRCULATION MAY PRODUCE ENOUGH LIFT FOR PRECIPITATION
PRODUCTION...ASSUMING ENOUGH LOW TO MID LEVEL MOISTURE...AND QPF
FIELDS FROM THE OPERATIONAL GFS AND EC BOTH SUGGEST PRECIPITATION
WILL BE REALIZED WEDNESDAY NIGHT/THURSDAY MORNING. WENT AHEAD WITH
POPS LATE WEDNESDAY INTO EARLY THURSDAY AS A RESULT. THE RIGHT-REAR
QUADRANT OF THE SAME MID LEVEL JET STREAK IS THEN EXPECTED TO PUSH
OVER NORTHERN PORTIONS OF THE CWA THURSDAY NIGHT INTO FRIDAY
MORNING...THUS BRINGING ANOTHER CHANCE FOR PRECIPITATION TO NORTHERN
PORTIONS OF OUR AREA. THE INTRODUCTION OF A ~40KT LOW LEVEL JET
STREAK WILL THEN BRING FURTHER CHANCES OF PRECIPITATION TO THE AREA
FRIDAY NIGHT INTO EARLY SATURDAY. BEYOND WEDNESDAY EVENING...LOW
LEVEL MOISTURE IS NOT OVERLY IMPRESSIVE AS SURFACE RIDGING REMAINS
ENTRENCHED ACROSS THE AREA AND AS A RESULT...INSTABILITY SUFFERS
GREATLY. LOW LEVEL MOISTURE FINALLY IMPROVES BY LATE FRIDAY AS LOW
LEVEL RETURN FLOW IS REALIZED ACROSS THE AREA...WITH DEEP LAYER
MUCAPE VALUES PERHAPS CLIMBING TO AROUND 1000J/KG BY FRIDAY NIGHT.
GIVEN ALL THIS...AM NOT INCLINED TO GO WITH ANY SEVERE WORDING IN
THE HWO BEYOND WEDNESDAY EVENING.
A SUBTLE COOLING TREND SHOULD BE NOTED ACROSS THE AREA WEDNESDAY AND
THURSDAY AS SURFACE RIDGING REMAINS OVER THE AREA. LOW LEVEL RETURN
FLOW AND RESULTANT LOW LEVEL WARM AIR ADVECTION WILL THEN PROMOTE A
WARMING TREND TO FINISH OUT THE EXTENDED FORECAST PERIOD. DESPITE
ANY TRENDS...TEMPERATURES DURING THE EXTENDED FORECAST PERIOD WILL
REMAIN AT NEAR OR ABOVE-NORMAL LEVELS FOR THIS TIME OF YEAR.
&&
.PREV DISCUSSION... /ISSUED 1044 PM CDT SAT MAY 19 2012/
AVIATION...06Z KGRI TAF. MAY START OFF WITH MVFR CONDITIONS AS
LOWER CLOUDS JUST TO THE WEST WRAPPING AROUND MID LEVEL
CIRCULATION CURRENTLY OVERHEAD AND MOVING ENE. CLEAR SLOT SOUTH
WILL BE CLOSE AND WILL NEED TO MONITOR...AS WE SHOULD EVENTUALLY
BECOME VFR AND HOW QUICKLY DEPENDS ON EXTENT OF WRAP AROUND
CLOUDS. SHOULD SEE CLEAR SKIES FOR MOST OF THE DAYTIME AND
EVENING ON SUNDAY AS SURFACE HIGH PRESSURE MOVES EAST OVER THE
AREA WITH MUCH DRIER AIR AND SUBSIDENCE ALOFT. THIS WILL ALLOW
WINDS TO BE A LITTLE LIGHTER ON SUNDAY STARTING OUT FROM THE
NORTH...THEN NORTHEAST AND EVENTUALLY EASTERLY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...BRYANT
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
328 AM CDT SUN MAY 20 2012
.SHORT TERM (TODAY-TUESDAY NIGHT)...CHALLENGE WILL BE NEAR TERM
SHOWERS ACROSS THE SOUTHEAST AND THEN PRECIP CHANCES MONDAY
AFTERNOON INTO TUESDAY NIGHT. 00Z MODELS IN DECENT AGREEMENT AND
WILL FOLLOW A BLEND FOR DETAILS. WILL USE ECMWF/NAM FOR LOW-LEVEL
MOISTURE AS GFS IS LIKELY TOO MOIST.
UPPER WAVE AND ASSOCIATED SHOWERS MAY LINGER ACROSS THE EXTREME SE
FA EARLY THIS MORNING...BUT SHOULD MOVE EAST BY 15Z. CURRENTLY...LOW-
LEVEL DRY AIR COMBINED WITH WEAKENING SHOWERS ACROSS THE FAR SE FA
ARE CREATING GUSTY WINDS 30-50 MPH. THESE GUSTY WINDS SHOULD BE
SHORT LIVED...AND ISSUED A SPS TO MENTION THE POSSIBILITY.
OTHERWISE...SURFACE RIDGING WILL MOVE INTO THE REGION TODAY. THERE
WILL BE AN UPPER LEVEL COLD POOL AND LIKELY AFTERNOON CU
DEVELOPMENT...BUT LARGE SCALE SUBSIDENCE SHOULD LIMIT COVERAGE TO
SCATTERED. THINKING THERE WILL BE ENOUGH SOLAR FOR MAX TEMPS INTO
THE 60S...POSSIBLY 70F ACROSS SOME LOCATIONS. RETURN FLOW BEGINS
TONIGHT ACROSS THE WESTERN FA...WITH MIN TEMPS LIKELY UPPER 30S
EAST TO MID 40S WEST.
SYSTEM BEGINS TO APPROACH THE REGION ON MONDAY. MUCH OF MONDAY
SHOULD BE PARTLY SUNNY WITH TEMPS INTO THE 70S. MODELS SUGGEST
THAT AN 850MB JET AND ASSOCIATED WARM AIR ADVECTION WILL LEAD TO
SCATTERED SHOWERS/THUNDER ACROSS THE NORTHERN FA LATE MONDAY
AFTERNOON INTO MONDAY NIGHT AND TUESDAY MORNING (PROPAGATING
EAST). INSTABILITY IS VERY WEAK.
ON TUESDAY...COLD FRONT WILL BE LOCATED SOMEWHERE ACROSS CENTRAL
DAKOTAS BY 00Z WED. MUCH OF TUESDAY AFTERNOON SHOULD REMAIN DRY AS
LOW-LEVEL MOISTURE IS MARGINAL AND CAPPING HOLDS. STRONG FORCING
FROM APPROACHING MID-LEVEL WAVE WILL BE REQUIRED TO INITIATE
CONVECTION. STRONG DEEP LAYER SHEAR AND SHOWALTER INDEX OF -4C TO
-6C COULD LEAD TO A PERIOD OF POSSIBLE SEVERE STORMS TUESDAY
EVENING INTO THE OVERNIGHT HOURS.
.LONG TERM (WEDNESDAY-SATURDAY)... ODELS CONTINUE TO REMAIN IN
DECENT AGREEMENT WITH THE EXTENDED PERIOD WITH ACTIVE 500MB SW
FLOW TO BRING POPS TO MOST PERIODS IN LATTER HALF OF THE WEEK.
SHORT WAVE MOVING ACROSS THE FA ON WEDNESDAY SHOULD HAVE AMPLE
MOISTURE TO WORK WITH AS DEW POINTS ARE EXPECTED TO LIFT INTO THE
50S AND NEAR 60 AHEAD OF FROPA... INITIATING SHOWERS AND TSTORMS.
SOME UNCERTAINTY ON THURSDAY WITH AREAL COVERAGE OF SHOWER
ACTIVITY AS GFS IS A SLOWER THAN THE ECMWF IN MOVING THE VORT MAX
OVER THE FA WITH LINGERING SHOWERS. A BRIEF BREAK IN THE AREAL
POPS COVERAGE ON FRIDAY BEFORE THE WARM SECTOR SURGES NORTH INTO
THE FA WITH THE INCREASED RIDGING IN THE CENTRAL PLAINS IN
RESPONSE TO THE DEEPENING WEST COAST TROUGH. THIS WAA WARRANTS
SLIGHT CHC POPS ON FRIDAY AND SATURDAY. TEMPS FOR THE PERIOD WILL
BE SEASONAL WITH HIGHS IN THE UPPER 60S AND MID 70S.
&&
.AVIATION...MVFR CIGS REMAIN AT BEMIDJI...AND CLEARING TREND IS
DIFFICULT TO FORECAST. WILL NEED TO MONITOR...THINKING MVFR
THRU 12Z-14Z USING 06Z RUC 925-850MB RELATIVE HUMIDITY. VFR
CONDITIONS THROUGH THE DAY WITH HIGH BASED CU POSSIBLE DURING THE
AFTERNOON HOURS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
TG/JK
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
215 AM EDT SUN MAY 20 2012
.SYNOPSIS...
THE STRONG 500 HPA RIDGE AND WEAK SURFACE RIDGE SHOULD PROVIDE FOR
ANOTHER FINE DAY SUNDAY. A NORTHERN STREAM WAVE APPROACHING COULD
PULL THE FIRST NAMED STORM OF THE YEAR...ALBERTO...UP THE COAST
MONDAY-TUESDAY WHICH COULD BRING A CHANCE OF RAIN TO EASTERN PA
MONDAY EVENING AND TUESDAY. A WEAK TROUGH WILL DOMINATE THROUGH
LATE WEDNESDAY...THEN A 500 HPA RIDGE SHOULD BUILD OVER THE
EASTERN UNITED STATES. BY THE END OF THE WEEK A 5880M RIDGE WITH
+1 TO +2 STANDARD DEVIATIONS HEIGHTS WILL BE OVER THE OHIO
VALLEY. IT SHOULD RAPIDLY WARM UP HERE THURSDAY INTO SATURDAY.
SHOULD BE WELL ABOVE NORMAL HERE TEMPERATURE WISE THUR-SUNDAY.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
HIGH PRESSURE OVER THE REGION WILL PROVIDE ANOTHER MCLEAR NIGHT
ACROSS CENTRAL PA WITH LIGHT WINDS. ORIGINALLY COOL/DRY AIR MASS
HAS MODIFIED CONSIDERABLY OVER THE LAST COUPLE DAYS. 06Z
TEMPS/DWPTS SEVERAL DEG ABV THOSE OF 24HRS AGO...SUGGESTING LOWS
THIS AM RANGING FROM THE U40S N MTNS...TO THE M50S ACROSS THE
LOWER SUSQ VALLEY.
CAN/T RULE OUT A BIT OF FOG ARND DAWN OVR THE SUSQ VALLEY...WHERE
NAM AND HRRR SFC RH RISES TO NR 100PCT BY 09Z. HOWEVER...HAVE
REMOVED MENTION IN FCST...GIVEN UNCERTAINTY AND ISOLATED NATURE IF
IT DOES FORM.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM MONDAY/...
FAIR WX CONTINUES SUNDAY AS A RIDGE OVER THE ATLANTIC EXTENDS INTO
OUR REGION. WE SHOULD HAVE WEAK EASTERLY FLOW SLIGHT RISE IN
RELATIVE HUMIDITY.
SHOULD BE A GOOD DAY AND NEW GUIDANCE STILL SEEMS TO KEEP HINTS OF
RAIN OFF UNTIL MONDAY. STILL NOT AN ENSEMBLE MEMBER HAS ANY RAIN
OVER OUR AREA UNTIL AFTER ABOUT ABOUT 1200 UTC ON MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
UPDATED GRIDS/FORECAST TO SHOW THE LATEST GEFS/SREF WITH BEST
CHANCE RAIN IN EXTREME SOUTHEAST PA A FEW HOURS EITHER SIDE OF 8
AM MONDAY. 18Z GEFS WOULD FAVOR SOME LIGHT RAIN IN EASTERN PA
BETWEEN 8 AND 4 PM ON MONDAY. SOME LOCALLY ENHANCED POPS IN NW PA
TOO MONDAY WITH THE MODEST PW SURGE AHEAD OF THE NORTHERN STREAM
FRONTAL SYSTEM. WOULD BE SHRA WITH TSTMS IN NW PA WITH CAPE VALUES
IN THE 600 TO 800JK-1 RANGE. IN EASTERN PA THE RAIN WOULD BE ON
COOLER MORE STABLE EASTERLY FLOW.
THE FRONT AND MOISTURE GET HUNG UP OVER PA TUESDAY. THUS THE
MODELS PRODUCE OVER 800JKG-1 OF CAPE TUESDAY. NO WINDS TO SPEAK
OF. BUT MODEST PROBABILITIES SHOWERS AND THUNDER LATE MORNING INTO
THE EVENING ON TUESDAY.
STILL SOME INSTABILITY TO DEAL WITH IN EASTERN PA WED. A FEW MORE
SHOWERS/TSTMS WITH MODEST CAPE MAINLY BELOW ABOUT 800JKG-1.
WE COOL OFF MONDAY-TUES WITH CLOUDS AND RAIN...EASTERLY FLOW
MONDAY IN EASTERN PA WITH COASTAL SYSTEM (ALBERTO). ALBERTO TO SE
AND AND SHORT WAVE AND FRONT TO NW MAKE MON-TUES BEST RAINFALL
POTENTIAL DAYS. AT THIS TIME LOOKING AT A FEW TENTHS. NOTHING BIG
AS PROBABILITIES OF 0.50 AND 1.00 INCHES STAY TO OUR EAST.
TRIED TO KEEP AS MUCH OF THE LATER PART OF THE WEEK DRY...GIVEN
BUILDING RIDGE ALOFT.
KEY THING IS WITH CLOSE 5880M RIDGE BUILDING IN LATER IN
WEEK...SURGE OF ABOVE NORMAL 850 HPA TEMPS WITH RELATIVELY LOW PW
VALUES SUGGESTING WARMING UP THURSDAY AND WARMER STILL FRIDAY AND
SATURDAY.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
A RIDGE OF HIGH PRESSURE WILL REMAIN NEARLY STATIONARY OVER
PENNSYLVANIA THROUGH SUNDAY...CONTINUING A PERIOD OF VFR
CONDITIONS WITH CLEAR SKIES AND LIGHT WINDS.
EASTERLY FLOW BEGINS TO INCREASE ACROSS THE REGION ON SUNDAY.
CLOUDS INCREASE SUNDAY NIGHT INTO MONDAY AS A DEEP LOW BACKS INTO
THE REGION FROM THE SOUTHEAST. SHOWERY WEATHER RETURNS EARLY
MONDAY WITH MVFR TO IFR CONDITIONS IN LOW CIGS AND VSBY POSSIBLE
IN RAIN SHOWERS ALONG THE LOWER SUSQ TAF SITES /MDT-LNS AND POSS
IPT/.
OUTLOOK...
SUN...VFR WITH A LIGHT...MAINLY EASTERLY WIND.
MON...SCATTERED MVFR CIGS AND VSBYS IN SHOWERS AND ISOLD
THUNDERSTORMS.
MON NIGHT THROUGH WEDNESDAY...MORE WIDESPREAD
REDUCED CIGS AND VSBYS LIKELY IN SHOWERS AND SCTD TSRA.
THU...PRIMARILY VFR. SCT SHRA/TSTM POSS MAINLY SE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...FITZGERALD
SHORT TERM...GRUMM
LONG TERM...GRUMM/MARTIN
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1152 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...THROUGH 06Z MONDAY
1152 PM CDT SAT MAY 19 2012
MAIN FORECAST CONCERN IS ON TIMING OF FRONT THROUGH THE TAF SITES
AND CONVECTION POTENTIAL. COLD FRONT NOW EXTENDING FROM NORTHWEST
WISCONSIN...SOUTHWEST INTO NORTHWEST IOWA. CONVECTION HAS BEEN
ONGOING ALL ALONG AND BEHIND IT...BUT HAS MADE VERY LITTLE
PROGRESS EASTWARD THIS EVENING. FRONT WILL MAKE SLOW PROGRESS
OVERNIGHT AND MOVE THROUGH TAF SITES BETWEEN 12Z-15Z. WITH WANING
INSTABILITIES AT THIS TIME DID ONLY MENTION -SHRA. 21.00Z NAM DOES
SHOW AN INVERTED TROUGH OVER THE AREA THIS AFTERNOON AS THE MAIN
SURFACE LOW MOVES EAST AND THUS LINGERS PRECIPITATION THROUGHOUT
MUCH OF THE DAY. INSTABILITIES ARE IN QUESTION WITH CLOUDS AND
FRONTAL POSITION...AS HIGHER INSTABILITIES WILL RESIDE EAST OF THE
TAF SITES. DID JUST KEPT MENTION OF SHOWERS GOING. PRECIPITATION
WILL END DURING THE LATE AFTERNOON/EARLY EVENING WITH SOME
DECREASE IN CLOUDS...ESPECIALLY AT KRST BEFORE 06Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
253 PM CDT SAT MAY 19 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...RABERDING
AREA FORECAST DISCUSSION...RETRANSMITTED...
NWS QUAD CITIES IA IL
641 AM CDT SUN MAY 20 2012
.UPDATE...
TRENDS IN SATELLITE/RADAR AND THE RAP MODEL NOW QUESTION IF
ANYTHING OTHER THAN SPRINKLES WILL OCCUR DURING THE MORNING HOURS.
RAP TRENDS ALSO INDICATE THE OVERALL FORCING WITH THE FRONT IS
WEAK BUT IT WILL BE MOVING ACROSS THE CWFA DURING PEAK HEATING.
MCS...LIFT...AND HEAVY RAIN TOOLS ALONG WITH THE OVERALL SYNOPTIC
FORCING SUGGEST CONVECTION MAY BE POSSIBLE THIS AFTERNOON WITH
DEVELOPMENT GENERALLY EAST OF THE MISSISSIPPI WHERE TEMPERATURES
WILL BE THE WARMEST. FCST SOUNDINGS FROM THE RAP ARE SUGGESTING
CONVECTIVE TEMPERATURES ARE AROUND 90 WHICH MAY NOT BE ACHIEVABLE
DUE TO CLOUD COVER.
WILL CONTINUE TO MONITOR TRENDS FOR A POSSIBLE UPDATE PRIOR TO 8
AM. ..08..
&&
.AVIATION...
COLD FRONT WILL MOVE THROUGH EASTERN IOWA/NORTHERN ILLINOIS AFT
18Z/20. VFR WX IS STILL GENERALLY EXPECTED AT ALL TAF SITES.
CONVECTION IS STILL IN QUESTION THIS AFTERNOON BUT TRENDS FROM THE
RAP MODEL SUGGEST IT WOULD OCCUR EAST OF KMLI/KBRL. SATELLITE
TRENDS INDICATE MVFR CONDITIONS DVLPG BEHIND THE FRONT WHICH
SHOULD AFFECT KCID/KDBQ AFT 21Z/20. HIGH PRESSURE BUILDING IN AFT
00Z/21 WILL EVENTUALLY ALLOW VFR CONDITIONS TO DVLP AGAIN BY
12Z/21 AT ALL TAF SITES. ..08..
&&
.PREV DISCUSSION... /ISSUED 327 AM CDT SUN MAY 20 2012/
SYNOPSIS...
06Z SFC ANALYSIS HAS A LOW IN SOUTHERN MINNESOTA WITH AN INFERRED
LOW JUST EAST OF KOFF. THE FRONTAL BOUNDARY CONNECTS WITH THE
SOUTHERN MINNESOTA LOW INTO CENTRAL KANSAS WHILE ANOTHER COLD
FRONT EXTENDED FROM THE KOFF LOW THROUGH EASTERN KANSAS AND INTO
WEST TEXAS. DEW POINTS AHEAD OF THE FRONTAL BOUNDARY WERE IN THE
50S WITH POCKETS OF LOW 60 DEW POINTS. BEHIND THE FRONT DEW POINTS
QUICKLY DROPPED OFF INTO THE 40S WITH SOME 30S IN THE FRONT RANGE
OF THE ROCKIES. SATELLITE/RADAR TRENDS SHOW THE PRECIPITATION
CONTINUING TO DECREASE ACROSS THE MIDWEST AS CLOUD TOPS WARM.
SHORT TERM...TODAY AND TONIGHT...
THE OVERALL FORCING ALONG THE FRONTAL BOUNDARY IS NOT GREAT WHICH
BRINGS INTO QUESTION THE POTENTIAL FOR PRECIPITATION THIS
AFTERNOON. CLOUD COVER MAY KEEP TEMPERATURES BELOW THE CONVECTIVE
TEMPERATURE. BASED ON CURRENT RADAR/SATELLITE TRENDS ALONG WITH
INPUT FROM THE RAP...WILL GO WITH SCHC POPS IN THE WESTERN 40
PERCENT OF THE CWFA THIS MORNING FOR ISOLATED SHOWERS. THE LIFT
TOOL SHOWS THE OVERALL CONVERGENCE CONTINUING TO WEAKEN SO
SPRINKLES MAY BE MORE APPROPRIATE THAN ISOLATED SHRA.
THIS AFTERNOON...ONCE THE COLD FRONT PASSES ANY PARTICULAR
LOCATION THE THREAT FOR ANY PRECIPITATION IS OVER. BASED ON
OBSERVATIONS AND INPUT FROM THE RAP...ROUGHLY THE EASTERN HALF TO
TWO THIRDS OF THE CWFA WILL HAVE A CHANCE FOR PRECIPITATION THIS
AFTERNOON. THE WEAK FORCING AND QUESTIONS ABOUT ACHIEVING
CONVECTIVE TEMPERATURE HAS RESULTED IN POPS BEING LOWERED. THE
EASTERN THIRD OF THE CWFA PROBABLY HAS THE BEST CHANCE AT SEEING
SOME SCATTERED SHRA/TSRA. THE CAA BEHIND THE FRONT IS QUITE STRONG
AS THE OVERALL SYSTEM CONTINUES TO STRENGTHEN SO TEMPERATURES
SHOULD SLOWLY FALL DURING THE AFTERNOON IN THE WESTERN PARTS OF
THE CWFA.
TONIGHT...LINGERING SHRA WILL END AROUND SUNSET IN THE FAR EASTERN
PARTS OF THE CWFA WHILE DRY CONDITIONS ARE EXPECTED ELSEWHERE.
SKIES WILL CLEAR FROM WEST TO EAST OVERNIGHT RESULTING IN A CHILLY
NIGHT. IT IS WITHIN THE REALM OF POSSIBILITY THAT FAVORED AREAS IN
THE NORTHWEST PART OF THE CWFA MAY DROP INTO THE LOWER 40S BEFORE
SUNRISE MONDAY. ..08..
LONG TERM...MONDAY THROUGH SATURDAY...
THE PERIOD FROM MONDAY INTO TUESDAY NIGHT APPEARS TO BE PREDICTABLY
QUIET AND PLEASANT WITH WIDE DIURNAL TEMPERATURE RANGES. AFTER A
CHILLY START TO THE DAY MONDAY...DEEP MIXING AND SUNSHINE WILL HELP
BOOST READINGS BACK TO THE LOWER 70S OVER THE CWA...WITH SOME
POSSIBLE MID 70S FAR SOUTH AND WEST. HIGH PRESSURE AND DRY AIR IN
PLACE MONDAY NIGHT WILL ALLOW FOR LOWS IN THE UPPER 40S TO LOWER
50S...WITH SOME LOCAL COLD SPOTS POSSIBLY DIPPING TO THE MID 40S.
MODERATION ALOFT BY TUESDAY SHOULD HELP JUMP WESTERN 1/2
TEMPERATURES INTO THE UPPER 70S TO LOWER 80S...WHILE THE EAST SEES
HIGHS IN THE MID 70S. WEDNESDAY THROUGH THURSDAY...HEAT WILL
CERTAINLY BUILD...WITH HIGHS IN THE LOWER TO UPPER 80S.
THE PATTERN MUCH DEBATED IN THE EXTENDED HAS BEEN THE POSITION OF A
LARGE SYNOPTIC RIDGE...AND THE CLOSENESS...OR LACK THERE OF OF A
BROAD WESTERN TROF...AS WELL AS JET ENERGY. THE DIFFERENCE BETWEEN
THE TWO HAS BEEN THE GFS/UKMET CAMP OF EPISODES OF THUNDERSTORMS
WITH A FRONT NEARBY...OF THE ECMWF/GEM CAMP SHOWING SUPER STRONG
UPPER RIDGING AND INTENSE MIDWEST HEAT. TONIGHTS 00Z MODELS ARE IN
BETTER AGREEMENT...AND THERE IS HOPE THAT CONFIDENCE ON A PATTERN IS
GOING UP. THE GFS AND EC CAMPS ARE NOW IN APPROXIMATE AGREEMENT WITH
THE FRONT NEARING THE CWA TOWARDS THURSDAY...AND REMAINING INTO
FRIDAY NIGHT. CONVECTION IS POSSIBLE...BUT ALSO MAY DEAL WITH STRONG
CAPPING. THUS...WE WILL SHOW A SLIGHT CHANCE FOR STORMS IN THE LATE
WEEK. TEMPERATURES SHOULD BE WARM THROUGH SATURDAY...AND IF THE
RIDGE CAN BUILD AS SHOWN BY THE EC SATURDAY...WE WILL BE HOT THIS
HOLIDAY WEEKEND. ERVIN
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
525 AM CDT SUN MAY 20 2012
...UPDATE FOR THE SHORT TERM FORECAST...
.UPDATE...
ISSUED AT 519 AM CDT SUN MAY 20 2012
UPDATED THE FORECAST TO INCLUDE THUNDER WITH THE ONGOING SMALL
AREA OF SHOWERS OVER PARTS OF WEST CENTRAL AND SOUTHWEST KANSAS
EARLY THIS MORNING. REFLECTIVITY IN THE CELLS HAS INCREASED A BIT
OVER THE PAST HOUR AND LIGHTNING DETECTION NETWORK HAS BEEN
INDICATING A FEW STRIKES. EXTRAPOLATION OF THE VORT MAX IN THE
WATER VAPOR IMAGERY SHOWS THE AREA OF PRECIPITATION MOVING INTO
CENTRAL KANSAS AROUND 13-15Z SO WILL HANG ON TO SOME SMALL POPS
AROUND LARNED AND LACROSSE THROUGH THAT TIME.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 335 AM CDT SUN MAY 20 2012
THE LATEST NAM AND RUC MODEL GUIDANCE SHOWS THE BAND OF 700 MILLIBAR
FRONTOGENETIC FORCING ACROSS FAR WESTERN KANSAS EARLY THIS MORNING.
THE MODELS MOVE THIS AREA OF FORCING EASTWARD AND WEAKEN IT
THROUGH SUNRISE. GIVEN THE GOING RADAR TRENDS, EXPECT THE
PRECIPITATION TO BE MOVING OUT OF WESTERN KANSAS AND THROUGH
CENTRAL KANSAS BY 12Z AS THE FORCING MOVES EAST AND WEAKENS.
WINDS HAVE BECOME LIGHT AND VARIABLE AS THE BOUNDARY LAYER
DECOUPLED THIS EVENING. SURFACE HIGH PRESSURE WILL BE BUILDING
INTO WESTERN KANSAS THROUGH THIS MORNING. WE SHOULD SEE A PERIOD
OF WINDS GUSTING TO AROUND 20 KNOTS OR SO DEVELOPING AFTER
SUNRISE. WINDS WILL DIMINISH AND SWITCH TO THE EAST/NORTHEAST THIS
AFTERNOON AS THE HIGH PRESSURE MOVES OFF TO THE EAST.
WIDELY SCATTERED THUNDERSTORMS WILL LIKELY DEVELOP OFF THE FRONT
RANGE OF THE ROCKIES THIS AFTERNOON AS SOME LIMITED INSTABILITY
DEVELOPS WITH CAPE VALUES AROUND 500 J/KG OR SO. MODEL SOUNDINGS
ACROSS FAR SOUTHWEST KANSAS ARE MORE STABLE SO EXPECT THAT ANY
THUNDERSTORMS THAT DEVELOP WILL PROBABLY STAY IN EASTERN COLORADO
BEFORE DIMINISHING WITH SUNSET.
SKIES SHOULD BE MOSTLY CLEAR TONIGHT AS UPPER LEVEL RIDGING CONTINUES
TO DEVELOP. LOW TEMPERATURES MAY FALL INTO THE UPPER 40S AROUND HAYS
AND LARNED CLOSER TO THE SURFACE HIGH PRESSURE. FARTHER WEST...LOWS
SHOULD STAY IN THE MID 50S AROUND ELKHART WHERE WINDS WILL STAY UP
A LITTLE MORE TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 335 AM CDT SUN MAY 20 2012
SHORT RANGE MODELS INDICATE A WEAK UPPER LEVEL RIDGE OF HIGH
PRESSURE DEVELOPING ACROSS THE ROCKIES EARLY MONDAY SETTING UP A
NORTHWESTERLY FLOW ALOFT ACROSS THE WESTERN HIGH PLAINS. MEANWHILE,
SURFACE HIGH PRESSURE WILL BE TRACKING EAST OUT OF THE NORTHERN
PLAINS INTO THE UPPER MIDWEST HELPING TO INFLUENCE A SOUTHEASTERLY
UPSLOPE FLOW ACROSS THE WESTERN HIGH PLAINS. AS A RESULT, DIURNALLY
DRIVEN ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ARE EXPECTED TO
DEVELOP JUST LEE OF THE ROCKIES MONDAY AFTERNOON AND EVENING,
POTENTIALLY DRIFTING EASTWARD INTO FAR SOUTHWESTERN KANSAS. WILL
RETAIN THE SLIGHT POPS ACROSS OUR FAR SOUTHWEST DUE TO THE EXPECTED
WEAK FLOW ALOFT COMBINED WITH THE UNCERTAINTY AS TO HOW FAR EAST
ANY DEVELOPING STORMS MAY REACH BEFORE DISSIPATING.
MEDIUM RANGE MODELS SHOW AN UPPER LEVEL TROUGH TRACKING SOUTHEAST
ACROSS THE PACIFIC NORTHWEST INTO THE ROCKY MOUNTAIN REGION TUESDAY
SETTING UP FOR ANOTHER CHANCE FOR PRECIP TO PORTIONS OF CENTRAL AND
WESTERN KANSAS. AS THE SYSTEM APPROACHES, INCREASING FIELDS OF
DIVERGENCE ALOFT WILL DEVELOP DOWNSTREAM OF THE TROUGH AXIS.
ADDITIONALLY, A PREVAILING LOW LEVEL SOUTHEASTERLY UPSLOPE FLOW
ACROSS THE WESTERN HIGH PLAINS WILL HELP WITH INCREASED FORCING AS
WELL AS ADVECT MORE MOISTURE NORTHWARD INTO THE REGION. AS A RESULT,
THE CHANCE FOR A FEW SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS
PORTIONS OF CENTRAL AND WESTERN KANSAS INTO TUESDAY. DRIER
CONDITIONS ARE EXPECTED ACROSS WESTERN KANSAS WEDNESDAY AS A
DEVELOPING SURFACE LOW LEE OF THE ROCKIES STRENGTHENS HELPING TO
DRAW DRIER AIR NORTHEASTWARD INTO SOUTHWEST KANSAS.
TEMPERATURES WILL BE SLIGHTLY WARMER GOING INTO MONDAY AS SURFACE
HIGH PRESSURE DROPS SOUTHEAST OUT OF THE NORTHERN PLAINS INTO THE
MID MISSISSIPPI RIVER VALLEY. THIS WILL HELP KEEP A SOUTHEASTERLY
LOW LEVEL FLOW IN PLACE ACROSS WESTERN KANSAS ALLOWING FOR SOME
MODEST WARM AIR ADVECTION. THE NAM, GFS, AND ECMWF SHOW H85
TEMPERATURES RANGING FROM THE MID TEENS(C) ACROSS CENTRAL KANSAS
TO NEAR 20C ALONG THE COLORADO BORDER. LOOK FOR HIGHS TO BE NEAR
TO JUST ABOVE 80F MONDAY AFTERNOON WITH A FEW UPPER 70S(F) STILL
POSSIBLE IN SOME LOCATIONS...MAINLY IN CENTRAL KANSAS. THE WARMING
TREND WILL CONTINUE INTO TUESDAY AS LEE SIDE TROUGHING STRENGTHENS
ACROSS EASTERN COLORADO. ENHANCED WARM AIR ADVECTION WITHIN A
STRONGER SOUTH TO SOUTHWESTERLY FLOW WILL RAISE H85 TEMPERATURES
UP TO NEAR 20C ACROSS CENTRAL KANSAS TO THE UPPER 20S(C) ACROSS
FAR SOUTHWEST KANSAS. EXPECT HIGHS FROM THE MID TO UPPER 80S(F) IN
CENTRAL KANSAS TUESDAY AFTERNOON TO THE LOWER TO MID 90S(F) IN
EXTREME SOUTHWEST KANSAS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1257 AM CDT SUN MAY 20 2012
WILL SHOW SOME SCATTERED TO BROKEN MID/UPPER LEVEL CLOUDINESS ACROSS
CENTRAL AND SOUTHWEST KANSAS THROUGH THE EARLY MORNING HOURS AS A WEAK
DISTURBANCE MOVES OVER THE AREA. AN ASSOCIATED SMALL AREA OF LIGHT RAIN
SHOWERS OR SPRINKLES WILL ALSO MOVE THROUGH THE AREA. THIS PRECIPITATION
IS VERY LIGHT SO VISIBILITIES SHOULD REMAIN IN THE VFR CATEGORY. NORTHERLY
WINDS MAY BECOME GUSTY FOR A TIME AFTER SUNRISE BUT SHOULD DECREASE
AGAIN AND SWITCH AROUND TO THE NORTHEAST AFTER 18Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 77 52 81 60 / 0 0 10 10
GCK 77 51 81 60 / 10 10 10 10
EHA 77 55 82 60 / 0 10 20 20
LBL 78 56 82 61 / 0 10 20 20
HYS 77 48 81 60 / 10 0 10 10
P28 78 55 80 61 / 20 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GERARD
SYNOPSIS...GERARD
SHORT TERM...GERARD
LONG TERM...JJOHNSON
AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS JACKSON KY
1132 AM EDT SUN MAY 20 2012
.UPDATE...
ISSUED AT 1131 AM EDT SUN MAY 20 2012
UPDATED THE NDFD FOR LATEST OBSERVATIONAL TRENDS. MADE SOME MINOR
ADJUSTMENTS TO AFTERNOON MAXIMUM TEMPERATURES IN A FEW SPOTS...WITH A
FEW SPOTS MAINLY IN THE SOUTH LOWERED SLIGHTLY...AND A FEW SPOTS
MAINLY IN THE NORTH INCREASED SLIGHTLY. THESE CHANGES WERE MINOR AND
DID NOT AFFECT THE ZFP...BUT THE ZFP WAS SENT TO UPDATE AFTERNOON
WORDING. HAVE DECIDED TO CONTINUE WITH THE ISOLATED...20 PERCENT
CHANCE OF SHOWERS AND THUNDERSTORMS IN THE HIGHER TERRAIN ALONG THE
VA BORDER...WITH THIS IDEA SUPPORTED BY THE 12Z NAM. THE RECENT RUNS
OF THE HRRR STILL SHOWING ISOLATED CONVECTION THIS AFTERNOON OVER THE
WESTERN PART OF THE FORECAST AREA...BUT NOT QUITE AS MUCH AS EARLIER
RUNS. DID NOT EXPAND THE AREA OF SLIGHT CHANCE THUNDERSTORMS
FROM THE CURRENT AREA BUT WILL CONTINUE TO MONITOR.
UPDATE ISSUED AT 942 AM EDT SUN MAY 20 2012
HAVE UPDATED NDFD FOR LATEST OBSERVATIONAL TRENDS...MAKING ONLY MINOR
MODIFICATIONS TO THE FORECAST DATABASE. SATELLITE SHOWS THE HIGH
CLOUDINESS OVER E KY THINNING. EXPECT THINNING TO CONTINUE PER
LATEST SATELLITE TRENDS...WITH THIS IDEA SUPPORTED BY 06Z NAM
GUIDANCE. MAIN QUESTION TO RESOLVE FOR THIS AFTERNOON IS WHETHER
THERE WILL BE ANY ISOLATED CONVECTION AND WHERE IT WOULD BE. FOR NOW
HAVE DECIDED TO CONTINUE WITH THE PREVIOUS FORECAST OF ISOLATED
CONVECTION FOR LETCHER...HARLAN AND BELL COUNTIES.
HOWEVER THERE ARE INDICATIONS ISOLATED CONVECTION COULD DEVELOP
FURTHER WEST...MORE ALONG THE EDGE OF WHERE THE HIGH CLOUD HAS BEEN.
VISIBLE SATELLITE SHOWING CU OVER PARTS OF E AND CENTRAL KY WEST OF A
LINE FROM CAMPTON TO MIDDLESBORO. CAN SEE THE CU THAT IS JUST WEST
OF JACKSON FROM THE NWS OFFICE. THE RECENT RUNS OF THE HRRR HAVE
POINTED TOWARDS ISOLATED CONVECTION WEST OF A LINE FROM SANDY HOOK TO
HARLAN THIS AFTERNOON. THINK THE NORTHERN EXTENT OF THIS MAY BE OVERDONE...AS
THERE WAS A SLIGHT CAP IN THE ILN SOUNDING...BUT THE NASHVILLE
SOUNDING WAS NOT CAPPED. THE SREF SUPPORTS THE IDEA OF CONVECTION
OVER OUR SW COUNTIES THIS AFTERNOON...AND THE HRRR INDICATES THE
GREATEST COVERAGE IN OUR FORECAST AREA WOULD BE OVER THE SOUTHWEST.
WILL MONITOR AS THE MORNING CONTINUES...AND MAY ADD ISOLATED
CONVECTION ALONG OUR SOUTHERN BORDER ALL THE WAY TO LAKE CUMBERLAND.
UPDATE ISSUED AT 638 AM EDT SUN MAY 20 2012
LOT MORE HIGH CLOUDS DEVELOPING UPSTREAM OVER THE PAST FEW HOURS. IF
THE HIGH CLOUDS PERSIST LIKE THEY APPEAR TO BE...WE MAY NOT DEVELOP
AS MUCH CU TODAY...AND THUS THE ISOLATED SHOWER/THUNDERSTORM CHANCES
IN THE SOUTHEAST COULD BE IN JEOPARDY. HOWEVER...STILL TIME FOR THIS
TO CHANGE...AND WON`T MAKE ANY CHANGES AT THIS TIME. ONCOMING
DAYSHIFT CAN REEVALUATE THE NEED FOR POPS IN THE SOUTHEAST.
OTHERWISE...TWEAKED MORNING TEMPERATURES AND DEWPOINTS TO BETTER
MATCH UP WITH OBSERVATIONS. THESE CHANGES WERE VERY MINOR...SO NO
NEED TO SEND OUT AN UPDATED FORECAST AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 305 AM EDT SUN MAY 20 2012
TROPICAL STORM ALBERTA CONTINUES TO SPIN OFF THE SOUTH CAROLINA COAST
THIS MORNING WITH A MID LEVEL TROUGH PUSHING ACROSS THE CENTRAL
PLAINS. BETWEEN THESE TWO SYSTEMS...A STRONG RIDGE OF HIGH PRESSURE
CONTINUES TO PRODUCE QUIET WEATHER FROM THE GREAT LAKES...SOUTHWARD
INTO THE OHIO VALLEY. THE SETUP WILL REMAIN VERY SIMILAR TO
YESTERDAY...WITH ANOTHER ROUND OF ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS DEVELOPING ACROSS THE TENNESSEE VALLEY REGION AS STRONG
INSTABILITY DEVELOPS MY MID AFTERNOON. MUCH LIKE YESTERDAY...A FEW
SHOWERS OR STORMS COULD SCRAPE THE COUNTIES IN KENTUCKY NEAR THE
VIRGINIA AND TENNESSEE BORDERS THIS AFTERNOON. THUS...WENT WITH
ISOLATED COVERAGE AS ANY SHOWERS AND STORMS WILL NOT AFFECT ANY LARGE
AREAS. THE SHOWERS AND STORMS WILL DISSIPATE BY SUNSET.
MEANWHILE...THE MID LEVEL TROUGH TO OUR WEST WILL PUSH INTO WESTERN
AND CENTRAL KENTUCKY LATE TONIGHT. SHOWERS AND PERHAPS A FEW
THUNDERSTORMS MAY ACCOMPANY THIS FEATURE...BUT ARE EXPECTED TO BE
WEAKENING AS THEY OUTRUN THE BETTER MID LEVEL SUPPORT. A FEW OF THESE
SHOWERS OR STORMS COULD SNEAK INTO OUR SOUTHWEST COUNTIES AROUND
DAYBREAK MONDAY. AS THE SHORTWAVE TROUGH PUSHES INTO THE OHIO VALLEY
ON MONDAY...THIS WILL PROVIDE BETTER MID/UPPER LEVEL SUPPORT FOR
SHOWER AND THUNDERSTORM DEVELOPMENT. IN ADDITION...INSTABILITY IS
EXPECTED TO INCREASE ACROSS THE REGION. THIS COMBINATION WILL LEAD TO
THE DEVELOPMENT OF A LINE OF SHOWERS AND STORMS AND WILL TRACK
EASTWARD ACROSS THE AREA MONDAY AFTERNOON. SHEAR IS VERY WEAK...IF
NOT NON-EXISTENT...SO NO THREAT FOR ANY SEVERE STORMS THIS TIME
AROUND. THIS LINE WILL WEAKEN AND DISSIPATE AS IT PUSHES TO OUR EAST
MONDAY NIGHT. IN THE WAKE OF THIS ACTIVITY...NOT MUCH SUPPORT FOR
ADDITIONAL DEVELOPMENT...ALTHOUGH AN ISOLATED SHOWER OR STORM IS
STILL POSSIBLE AS THE MID LEVEL THROUGH REMAINS ANCHORED ACROSS OUR
REGION. WENT WITH LIKELY POPS ON MONDAY WITH THE GOOD DYNAMICS AND
INSTABILITY AROUND...AND DROPPED POPS BACK TO MAINLY SLIGHT CHANCE
FOR MONDAY NIGHT.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 305 AM EDT SUN MAY 20 2012
THE MODELS CONTINUE TO HAVE SOME DIFFERENCES ALOFT WITH THE TROUGH
DIVING THROUGH THE OHIO VALLEY AT THE START OF THE EXTENDED. THE NAM
APPEARS TO BE THE MAIN OUTLIER HERE WITH A DEEPER AND SLOWER CLOSED
LOW SETTLING INTO OHIO THAN THE OTHER MODELS. BY CONTRAST THEY
REMAIN PROGRESSIVE INTO WEDNESDAY...THOUGH THE ECMWF DOES CLOSE OFF
A WEAKER VERSION OF ITS LOW FROM YESTERDAY OVER THE SOUTHERN
APPALACHIANS. THE GFS...IN CONTRAST...BRINGS IN RIDGING DURING THIS
TIME KEEPING JUST A WEAK HINT OF A LOW WELL EAST OF THE OTHER
MODELS. BY THURSDAY MORNING...THE ECMWF TAKES THE UPPER LOW EAST...
THOUGH IT STILL LAGS THE OTHER MODELS. THROUGH THE FIRST PART OF THE
EXTENDED...A BLEND IS PREFERRED...WITH SOME FAVORING THE
SLOWER/DEEPER ECMWF SOLUTION. LATER...THOUGH...THE MODELS ARE IN
BETTER AGREEMENT...AT LEAST LOCALLY...WITH RIDGING BUILDING OVERHEAD
IN RESPONSE TO A DEEP LOW PUSHING ASHORE ON THE WEST COAST. THIS
RIDGE SHOULD PROVIDE A PROTECTIVE DOME OVER THE OHIO VALLEY AND EAST
KENTUCKY HEADING INTO THE WEEKEND WHILE SHORTWAVES MOVE PAST WELL TO
THE NORTH.
SENSIBLE WEATHER WILL FEATURE STILL DECENT CHANCES OF SHOWERS AND
THUNDERSTORMS DURING THE DAY TUESDAY...FAVORING THE EAST...BENEATH
THE UPPER LOW AND ITS WEAK SFC REFLECTION OVER THE EASTERN OHIO
VALLEY. HAVE GONE WITH A DIURNAL PEAK IN THE MID TO LATE AFTERNOON
FOR POPS AND SKY COVER. A SMALL THREAT FOR CONVECTION WILL REMAIN IN
THE AREA ON WEDNESDAY AS WEAK HIGH PRESSURE SLOWLY BUILDS INTO THE
AREA FROM THE WEST AND THE UPPER LOW STARTS TO FILL AND MOVE OFF TO
THE EAST. THE CLOUDS AND PCPN WILL BE ENOUGH TO KEEP TEMPERATURES ON
THE COOL SIDE OF NORMAL FOR MOST PLACES TUESDAY AND WEDNESDAY BEFORE
A SIGNIFICANT WARMUP BEGINS IN EARNEST FRIDAY WITH THE ARRIVAL OF
SFC HIGH PRESSURE AND RIDGING ALOFT. THESE WILL COMBINE TO LIMIT
PCPN CHANCES THROUGH THE REMAINDER OF THE EXTENDED AND ALLOW
TEMPERATURES TO TAKE A RUN AT 90 DEGREES IN MANY EAST KENTUCKY
LOCATIONS BY SATURDAY AFTERNOON.
THE GRID LOAD CAME IN FAIRLY DECENT WITH A REASONABLE EMPHASIS ON
THE ECMWF SOLUTION. DID FINE TUNE THE POPS THROUGH WEDNESDAY FOR
MORE OF A DIURNAL FACTOR AND LESS IN THE SOUTHWEST THAN WAS LOADED.
ALSO...ADDED SOME USUAL TERRAIN BASED DETAILS TO THE LOW TEMPERATURE
GRIDS WEDNESDAY THROUGH FRIDAY NIGHT AS WE CONTINUE TO DRY OUT AND
SOUTHWEST FLOW KICKS IN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 638 AM EDT SUN MAY 20 2012
AFTER MORNING FOG BURNS OFF...VFR CONDITIONS WILL PREVAIL ACROSS
EASTERN KENTUCKY THROUGH THIS EVENING. DEPENDING ON HOW WELL
DEWPOINTS CAN OR CANNOT MIX OUT THIS AFTERNOON...WE COULD BE LOOKING
AT ANOTHER NIGHT OF PATCHY VALLEY FOG...MAINLY IMPACTING KLOZ WITH
ANOTHER BRIEF PERIOD OF MVFR FOG EARLY TOMORROW MORNING.
HOWEVER...WITH DRIER AIR OFF TO OUR EAST...IF SOME OF THIS CAN ADVECT
INTO OUR REGION TODAY...THE FOG THREAT MAY BE MUCH LESS TONIGHT.
OTHERWISE...HIGH CLOUDS WILL DOMINATE THE SKIES TODAY...BUT IF WE CAN
THIN OUT THESE CLOUDS ENOUGH...WE COULD GET SOME 5-6KFT CU TO
DEVELOP.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...KAS
LONG TERM....GREIF
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
942 AM EDT SUN MAY 20 2012
.UPDATE...
ISSUED AT 942 AM EDT SUN MAY 20 2012
HAVE UPDATED NDFD FOR LATEST OBSERVATIONAL TRENDS...MAKING ONLY MINOR
MODIFICATIONS TO THE FORECAST DATABASE. SATELLITE SHOWS THE HIGH
CLOUDINESS OVER E KY THINNING. EXPECT THINNING TO CONTINUE PER
LATEST SATELLITE TRENDS...WITH THIS IDEA SUPPORTED BY 06Z NAM
GUIDANCE. MAIN QUESTION TO RESOLVE FOR THIS AFTERNOON IS WHETHER
THERE WILL BE ANY ISOLATED CONVECTION AND WHERE IT WOULD BE. FOR NOW
HAVE DECIDED TO CONTINUE WITH THE PREVIOUS FORECAST OF ISOLATED
CONVECTION FOR LETCHER...HARLAN AND BELL COUNTIES.
HOWEVER THERE ARE INDICATIONS ISOLATED CONVECTION COULD DEVELOP
FURTHER WEST...MORE ALONG THE EDGE OF WHERE THE HIGH CLOUD HAS BEEN.
VISIBLE SATELLITE SHOWING CU OVER PARTS OF E AND CENTRAL KY WEST OF A
LINE FROM CAMPTON TO MIDDLESBORO. CAN SEE THE CU THAT IS JUST WEST
OF JACKSON FROM THE NWS OFFICE. THE RECENT RUNS OF THE HRRR HAVE
POINTED TOWARDS ISOLATED CONVECTION WEST OF A LINE FROM SANDY HOOK TO
HARLAN THIS AFTERNOON. THINK THE NORTHERN EXTENT OF THIS MAY BE OVERDONE...AS
THERE WAS A SLIGHT CAP IN THE ILN SOUNDING...BUT THE NASHVILLE
SOUNDING WAS NOT CAPPED. THE SREF SUPPORTS THE IDEA OF CONVECTION
OVER OUR SW COUNTIES THIS AFTERNOON...AND THE HRRR INDICATES THE
GREATEST COVERAGE IN OUR FORECAST AREA WOULD BE OVER THE SOUTHWEST.
WILL MONITOR AS THE MORNING CONTINUES...AND MAY ADD ISOLATED
CONVECTION ALONG OUR SOUTHERN BORDER ALL THE WAY TO LAKE CUMBERLAND.
UPDATE ISSUED AT 638 AM EDT SUN MAY 20 2012
LOT MORE HIGH CLOUDS DEVELOPING UPSTREAM OVER THE PAST FEW HOURS. IF
THE HIGH CLOUDS PERSIST LIKE THEY APPEAR TO BE...WE MAY NOT DEVELOP
AS MUCH CU TODAY...AND THUS THE ISOLATED SHOWER/THUNDERSTORM CHANCES
IN THE SOUTHEAST COULD BE IN JEOPARDY. HOWEVER...STILL TIME FOR THIS
TO CHANGE...AND WON`T MAKE ANY CHANGES AT THIS TIME. ONCOMING
DAYSHIFT CAN REEVALUATE THE NEED FOR POPS IN THE SOUTHEAST.
OTHERWISE...TWEAKED MORNING TEMPERATURES AND DEWPOINTS TO BETTER
MATCH UP WITH OBSERVATIONS. THESE CHANGES WERE VERY MINOR...SO NO
NEED TO SEND OUT AN UPDATED FORECAST AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 305 AM EDT SUN MAY 20 2012
TROPICAL STORM ALBERTA CONTINUES TO SPIN OFF THE SOUTH CAROLINA COAST
THIS MORNING WITH A MID LEVEL TROUGH PUSHING ACROSS THE CENTRAL
PLAINS. BETWEEN THESE TWO SYSTEMS...A STRONG RIDGE OF HIGH PRESSURE
CONTINUES TO PRODUCE QUIET WEATHER FROM THE GREAT LAKES...SOUTHWARD
INTO THE OHIO VALLEY. THE SETUP WILL REMAIN VERY SIMILAR TO
YESTERDAY...WITH ANOTHER ROUND OF ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS DEVELOPING ACROSS THE TENNESSEE VALLEY REGION AS STRONG
INSTABILITY DEVELOPS MY MID AFTERNOON. MUCH LIKE YESTERDAY...A FEW
SHOWERS OR STORMS COULD SCRAPE THE COUNTIES IN KENTUCKY NEAR THE
VIRGINIA AND TENNESSEE BORDERS THIS AFTERNOON. THUS...WENT WITH
ISOLATED COVERAGE AS ANY SHOWERS AND STORMS WILL NOT AFFECT ANY LARGE
AREAS. THE SHOWERS AND STORMS WILL DISSIPATE BY SUNSET.
MEANWHILE...THE MID LEVEL TROUGH TO OUR WEST WILL PUSH INTO WESTERN
AND CENTRAL KENTUCKY LATE TONIGHT. SHOWERS AND PERHAPS A FEW
THUNDERSTORMS MAY ACCOMPANY THIS FEATURE...BUT ARE EXPECTED TO BE
WEAKENING AS THEY OUTRUN THE BETTER MID LEVEL SUPPORT. A FEW OF THESE
SHOWERS OR STORMS COULD SNEAK INTO OUR SOUTHWEST COUNTIES AROUND
DAYBREAK MONDAY. AS THE SHORTWAVE TROUGH PUSHES INTO THE OHIO VALLEY
ON MONDAY...THIS WILL PROVIDE BETTER MID/UPPER LEVEL SUPPORT FOR
SHOWER AND THUNDERSTORM DEVELOPMENT. IN ADDITION...INSTABILITY IS
EXPECTED TO INCREASE ACROSS THE REGION. THIS COMBINATION WILL LEAD TO
THE DEVELOPMENT OF A LINE OF SHOWERS AND STORMS AND WILL TRACK
EASTWARD ACROSS THE AREA MONDAY AFTERNOON. SHEAR IS VERY WEAK...IF
NOT NON-EXISTENT...SO NO THREAT FOR ANY SEVERE STORMS THIS TIME
AROUND. THIS LINE WILL WEAKEN AND DISSIPATE AS IT PUSHES TO OUR EAST
MONDAY NIGHT. IN THE WAKE OF THIS ACTIVITY...NOT MUCH SUPPORT FOR
ADDITIONAL DEVELOPMENT...ALTHOUGH AN ISOLATED SHOWER OR STORM IS
STILL POSSIBLE AS THE MID LEVEL THROUGH REMAINS ANCHORED ACROSS OUR
REGION. WENT WITH LIKELY POPS ON MONDAY WITH THE GOOD DYNAMICS AND
INSTABILITY AROUND...AND DROPPED POPS BACK TO MAINLY SLIGHT CHANCE
FOR MONDAY NIGHT.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 305 AM EDT SUN MAY 20 2012
THE MODELS CONTINUE TO HAVE SOME DIFFERENCES ALOFT WITH THE TROUGH
DIVING THROUGH THE OHIO VALLEY AT THE START OF THE EXTENDED. THE NAM
APPEARS TO BE THE MAIN OUTLIER HERE WITH A DEEPER AND SLOWER CLOSED
LOW SETTLING INTO OHIO THAN THE OTHER MODELS. BY CONTRAST THEY
REMAIN PROGRESSIVE INTO WEDNESDAY...THOUGH THE ECMWF DOES CLOSE OFF
A WEAKER VERSION OF ITS LOW FROM YESTERDAY OVER THE SOUTHERN
APPALACHIANS. THE GFS...IN CONTRAST...BRINGS IN RIDGING DURING THIS
TIME KEEPING JUST A WEAK HINT OF A LOW WELL EAST OF THE OTHER
MODELS. BY THURSDAY MORNING...THE ECMWF TAKES THE UPPER LOW EAST...
THOUGH IT STILL LAGS THE OTHER MODELS. THROUGH THE FIRST PART OF THE
EXTENDED...A BLEND IS PREFERRED...WITH SOME FAVORING THE
SLOWER/DEEPER ECMWF SOLUTION. LATER...THOUGH...THE MODELS ARE IN
BETTER AGREEMENT...AT LEAST LOCALLY...WITH RIDGING BUILDING OVERHEAD
IN RESPONSE TO A DEEP LOW PUSHING ASHORE ON THE WEST COAST. THIS
RIDGE SHOULD PROVIDE A PROTECTIVE DOME OVER THE OHIO VALLEY AND EAST
KENTUCKY HEADING INTO THE WEEKEND WHILE SHORTWAVES MOVE PAST WELL TO
THE NORTH.
SENSIBLE WEATHER WILL FEATURE STILL DECENT CHANCES OF SHOWERS AND
THUNDERSTORMS DURING THE DAY TUESDAY...FAVORING THE EAST...BENEATH
THE UPPER LOW AND ITS WEAK SFC REFLECTION OVER THE EASTERN OHIO
VALLEY. HAVE GONE WITH A DIURNAL PEAK IN THE MID TO LATE AFTERNOON
FOR POPS AND SKY COVER. A SMALL THREAT FOR CONVECTION WILL REMAIN IN
THE AREA ON WEDNESDAY AS WEAK HIGH PRESSURE SLOWLY BUILDS INTO THE
AREA FROM THE WEST AND THE UPPER LOW STARTS TO FILL AND MOVE OFF TO
THE EAST. THE CLOUDS AND PCPN WILL BE ENOUGH TO KEEP TEMPERATURES ON
THE COOL SIDE OF NORMAL FOR MOST PLACES TUESDAY AND WEDNESDAY BEFORE
A SIGNIFICANT WARMUP BEGINS IN EARNEST FRIDAY WITH THE ARRIVAL OF
SFC HIGH PRESSURE AND RIDGING ALOFT. THESE WILL COMBINE TO LIMIT
PCPN CHANCES THROUGH THE REMAINDER OF THE EXTENDED AND ALLOW
TEMPERATURES TO TAKE A RUN AT 90 DEGREES IN MANY EAST KENTUCKY
LOCATIONS BY SATURDAY AFTERNOON.
THE GRID LOAD CAME IN FAIRLY DECENT WITH A REASONABLE EMPHASIS ON
THE ECMWF SOLUTION. DID FINE TUNE THE POPS THROUGH WEDNESDAY FOR
MORE OF A DIURNAL FACTOR AND LESS IN THE SOUTHWEST THAN WAS LOADED.
ALSO...ADDED SOME USUAL TERRAIN BASED DETAILS TO THE LOW TEMPERATURE
GRIDS WEDNESDAY THROUGH FRIDAY NIGHT AS WE CONTINUE TO DRY OUT AND
SOUTHWEST FLOW KICKS IN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 638 AM EDT SUN MAY 20 2012
AFTER MORNING FOG BURNS OFF...VFR CONDITIONS WILL PREVAIL ACROSS
EASTERN KENTUCKY THROUGH THIS EVENING. DEPENDING ON HOW WELL
DEWPOINTS CAN OR CANNOT MIX OUT THIS AFTERNOON...WE COULD BE LOOKING
AT ANOTHER NIGHT OF PATCHY VALLEY FOG...MAINLY IMPACTING KLOZ WITH
ANOTHER BRIEF PERIOD OF MVFR FOG EARLY TOMORROW MORNING.
HOWEVER...WITH DRIER AIR OFF TO OUR EAST...IF SOME OF THIS CAN ADVECT
INTO OUR REGION TODAY...THE FOG THREAT MAY BE MUCH LESS TONIGHT.
OTHERWISE...HIGH CLOUDS WILL DOMINATE THE SKIES TODAY...BUT IF WE CAN
THIN OUT THESE CLOUDS ENOUGH...WE COULD GET SOME 5-6KFT CU TO
DEVELOP.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...KAS
LONG TERM....GREIF
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1110 AM EDT SUN MAY 20 2012
.SYNOPSIS...
HIGH PRES OVR NRN NEW ENGLAND CONTINUES TO NOSE DOWN THE ERN
SEABOARD THIS AFTERNOON. THE ARE TWO AREAS OF LOW PRESSURE - A
WEAK SYSTEM WELL E OF VIRGINIA BEACH AND TROPICAL STORM ALBERTO -
OFF THE SOUTH CAROLINA COAST. LOW PRESSURE WILL GRADUALLY LIFT
NORTHEASTWARD MONDAY THROUGH THE MID-ATLANTIC...AS A FRONT MOVES
IN FROM THE WEST FOR TUESDAY AND WEDNESDAY. HIGH PRESSURE SLOWLY
BUILDS IN FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE WILL REMAIN OVER THE REGION TODAY WHILE LOW PRESSURE
RETROGRADES WESTWARD TOWARD THE NORTH CAROLINA COAST. TROPICAL
STORM ALBERTO REMAINS OFF THE SOUTH CAROLINA COAST...BUT IT WILL
NOT HAVE AN IMPACT ON OUR WEATHER.
MOISTURE WILL WRAP AROUND THE LOW OFF THE NORTH CAROLINA
COAST...CAUSING CLOUDS TO INCREASE ESPECIALLY ACROSS LOWER
SOUTHERN MARYLAND INTO CENTRAL VIRGINIA. ELSEWHERE...PLENTY OF
SUNSHINE IS EXPECTED ALONG WITH DRY CONDITIONS. MAX TEMPS WILL
RANGE FROM THE MID 70S ACROSS LOWER SOUTHERN MARYLAND WHERE MORE
CLOUD COVER IS EXPECTED...TO THE LOWER AND MIDDLE 80S ACROSS MOST
OTHER LOCATIONS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
FOR TNGT MDLS..ESPECIALLY THE NAM...SEEM SOMEWHAT AGGRESSIVE ON
BRINGING RAFL INTO THE RGN IN ASSO W/ THE NRN CSTL LOW (NOT
ALBERTO...WHICH IS RMNG FURTHER S). IT`S INTERESTING TO NOTE THAT
THE HRRR IS SHOWING EVEN NOW A FAIRLY DVLPD SPIRAL BANDING OF PCPN
OFF THE DELMARVA...BUT ON IR STLT IT LOOKS AS IF THERE`S BARELY
EVEN ANY CLD IN ASSO W/ IT. SREF SHOWS THE LOW APRCHG THE CST LN
THIS EVE WHILE WEAKENING ERLY ONSHORE FLOW WL ADVECT SOME MOISTURE
INTO CWA. QUSTN THEN IS HOW FAR W AND HOW MUCH? AND WL ALBERTO
TAKE ENERGY FM THE NRN LOW? I HV CUT BACK ON QPF...AND PUSHED
BACK THE TIMING ABT 6 HRS...PSBLY LGT RA REACHING DC BY 06Z.
WOULDN`T BE SURPRISED IF NO PCPN OCCURS W OF THE BLUE RDG...AND HV
CUT WRN CWA POPS TO LO CHC. BEST CHC FOR RAFL OVRNGT WL LKLY BE LWR
SRN MD.
LOWS IN THE 50S XCPT L60S IN THE CITIES/ALONG THE BAY.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
STACKED LOPRES...MOSTLY UNRELATED TO TROPICAL STORM ALBERTO...WILL CONT WWD
DRIFT INTO MID-ATLC MON. HIGH CHC/LOW LIKELY SHWRS AND ISOLATED
THUNDER FOR MON...WITH DIURNAL PEAK IN CNVCTN. MON NGT PCPN WANES AS
CLOSED LOW OPENS AND IS PULLED NEWD/ABSORBED BY APPROACHING NRN
STREAM ULVL TROF. TROF WILL BE BLOCKED BY STRONG BERMUDA RDGG AND
DRAW STATIONARY TUE...EVOLVING INTO CLOSED LOPRES CNTRD S OF RGN ON
WED. AT SFC...TROF/CDFNT WILL CROSS APLCNS TUE...INDUCING SCT/NUM
SHWRS/TSTMS. TEMPS SHUD BE REGULATED BY XTNSV CLOUD COVER
MON...SUPPRESSING MAXIMA TO L/M70S. TUE SHUD HAVE SOME BREAKS IN
CLOUDS...ALLOWING TEMPS TO REACH AOA 80F MOST RGN...THUS THE BETTER
TSTM CHCS. CONFIDENCE IN AFOREMENTIONED IS LOW...AS GUIDANCE IS NOT
IN AGREEMENT AND ALBERTO IS ESPECIALLY NOT WELL HANDLED BY MODELS
ATTM.
WITH M/ULVL LOPRES S/W OF RGN TUE NGT/WED...SFC TROF AXIS WILL
MEANDER THRU CWA AND GRADUALLY WASH OUT...WITH PLENTY MOISTURE IN
PLACE...CHC POPS WARRANTED. GUIDANCE SUGGESTS THAT ANOTHER NRN
BRANCH TROF WILL BCM DOMINATE ACRS PLAINS THU/FRI...ALLOWING SWLY
FLOW TO ESTABLISH ACRS ERN CONUS. WITH THIS...BERMUDA RIDGE WOULD
BUILD INTO ERN CONUS...TRIGGERING DRIER/WARMER CONDS FOR MID-ATLC
FOR WKS END. STILL...LLVL MOISTURE WILL BE DECENT...SO ISOLATED/SCT
MAINLY DIURNAL CNVCTN CANT BE RULED OUT THRU XTDD FCST.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
VFR CONDS TDA. CLDS XPCTD TO BEGIN TO LOWER TNGT...W/ CIGS DROPPING
INTO THE MVFR RANGE OVERNIGHT. IFR CIGS ARE POSSIBLE AS WELL. LGT
RAIN MAY IMPACT THE TERMINALS OVERNIGHT.
SCT/NUM SHWRS/PSBLY TSTMS WILL IMPACT TERMINALS MON THRU WED.
HIGHLY UNCERTAIN AS TO EXTENT OF PREVAILING FLIGHT
RESTRICTIONS...BUT AT LEAST PERIODS OF SUB-VFR CIGS/VBSYS APPEAR
PLAUSIBLE WITH MOIST ELY FLOW IN PLACE. POPS GRADUALLY DIMINISH FOR
SECOND HALF OF WEEK...AS HIPRES BUILDS IN.
&&
.MARINE...
HIGH PRESSURE WILL REMAIN OVER THE WATERS THIS AFTERNOON...BUT LOW
PRESSURE WILL RETROGRADE INTO NORTH CAROLINA THROUGH TONIGHT. THE
PRESSURE GRADIENT BETWEEN THESE TWO SYSTEMS WILL CAUSE WIND GUSTS
AROUND 20 KNOTS ACROSS THE WATERS THIS AFTERNOON AND EARLY
EVENING. A SMALL CRAFT ADVISORY IS IN EFFECT DURING THIS TIME. THE
SMALL CRAFT ADVISORY CONTINUES THROUGH TONIGHT FOR THE MARYLAND
CHESAPEAKE BAY SOUTH OF SANDY POINT AND THE LOWER TIDAL POTOMAC
RIVER FROM COBB ISLAND TO SMITH POINT.
NELY FLOW CONTS MON/TUE. GUSTS ON MON MAY APPROACH SCA
THRESHOLD...BUT CONFIDENCE TO LOW ATTM FOR EXTENSION OF HEADLINES.
LOPRES RMNS IN VICINITY THRU MIDWK...WITH SCT/NUM SHWRS/TSTMS XPCD.
SFC TROF/CDFNT APPROACHES TUE NGT/WED...WITH HIPRES SLOWLY BUILDING
IN THEREAFTER.
&&
.TIDES/COASTAL FLOODING...
WITH PROLONGED ELY FLOW AND LWRG PRESSURE ACRS CHESAPEAKE BAY...
MINOR COASTAL FLOODING LOOKS LIKELY WITH MON MRNGS HIGH TIDE.
FAVORABLE FLOW WILL CONT MON INTO TUE...SO ADDITIONAL COASTAL
FLOODING OF SENSITIVE LOCATIONS IS POSSIBLE AGAIN DURING HIGH
TIDES THIS PERIOD.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ530-
531-535-536-538-539.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ532>534-537-
540>543.
&&
$$
PRODUCTS...LASORSA/WOODY!/SBK
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
931 AM EDT SUN MAY 20 2012
.SYNOPSIS...
HIGH PRES OVR NRN NEW ENGLAND CONTINUES TO NOSE DOWN THE ERN
SEABOARD THIS AFTERNOON. THE ARE TWO AREAS OF LOW PRESSURE - A
WEAK SYSTEM WELL E OF VIRGINIA BEACH AND TROPICAL STORM ALBERTO -
OFF THE SOUTH CAROLINA COAST. LOW PRESSURE WILL GRADUALLY LIFT
NORTHEASTWARD MONDAY THROUGH THE MID-ATLANTIC...AS A FRONT MOVES
IN FROM THE WEST FOR TUESDAY AND WEDNESDAY. HIGH PRESSURE SLOWLY
BUILDS IN FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE WILL REMAIN OVER THE REGION TODAY WHILE LOW PRESSURE
RETROGRADES WESTWARD TOWARD THE NORTH CAROLINA COAST. TROPICAL
STORM ALBERTO REMAINS OFF THE SOUTH CAROLINA COAST...BUT IT WILL
NOT HAVE AN IMPACT ON OUR WEATHER.
MOISTURE WILL WRAP AROUND THE LOW OFF THE NORTH CAROLINA
COAST...CAUSING CLOUDS TO INCREASE ESPECIALLY ACROSS LOWER
SOUTHERN MARYLAND INTO CENTRAL VIRGINIA. ELSEWHERE...PLENTY OF
SUNSHINE IS EXPECTED ALONG WITH DRY CONDITIONS. MAX TEMPS WILL
RANGE FROM THE MID 70S ACROSS LOWER SOUTHERN MARYLAND WHERE MORE
CLOUD COVER IS EXPECTED...TO THE LOWER AND MIDDLE 80S ACROSS MOST
OTHER LOCATIONS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
FOR TNGT MDLS..ESPECIALLY THE NAM...SEEM SOMEWHAT AGGRESSIVE ON
BRINGING RAFL INTO THE RGN IN ASSO W/ THE NRN CSTL LOW (NOT
ALBERTO...WHICH IS RMNG FURTHER S). IT`S INTERESTING TO NOTE THAT
THE HRRR IS SHOWING EVEN NOW A FAIRLY DVLPD SPIRAL BANDING OF PCPN
OFF THE DELMARVA...BUT ON IR STLT IT LOOKS AS IF THERE`S BARELY
EVEN ANY CLD IN ASSO W/ IT. SREF SHOWS THE LOW APRCHG THE CST LN
THIS EVE WHILE WEAKENING ERLY ONSHORE FLOW WL ADVECT SOME MOISTURE
INTO CWA. QUSTN THEN IS HOW FAR W AND HOW MUCH? AND WL ALBERTO
TAKE ENERGY FM THE NRN LOW? I HV CUT BACK ON QPF...AND PUSHED
BACK THE TIMING ABT 6 HRS...PSBLY LGT RA REACHING DC BY 06Z.
WOULDN`T BE SURPRISED IF NO PCPN OCCURS W OF THE BLUE RDG...AND HV
CUT WRN CWA POPS TO LO CHC. BEST CHC FOR RAFL OVRNGT WL LKLY BE LWR
SRN MD.
LOWS IN THE 50S XCPT L60S IN THE CITIES/ALONG THE BAY.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
STACKED LOPRES...MOSTLY UNRELATED TO TROPICAL STORM ALBERTO...WILL CONT WWD
DRIFT INTO MID-ATLC MON. HIGH CHC/LOW LIKELY SHWRS AND ISOLATED
THUNDER FOR MON...WITH DIURNAL PEAK IN CNVCTN. MON NGT PCPN WANES AS
CLOSED LOW OPENS AND IS PULLED NEWD/ABSORBED BY APPROACHING NRN
STREAM ULVL TROF. TROF WILL BE BLOCKED BY STRONG BERMUDA RDGG AND
DRAW STATIONARY TUE...EVOLVING INTO CLOSED LOPRES CNTRD S OF RGN ON
WED. AT SFC...TROF/CDFNT WILL CROSS APLCNS TUE...INDUCING SCT/NUM
SHWRS/TSTMS. TEMPS SHUD BE REGULATED BY XTNSV CLOUD COVER
MON...SUPPRESSING MAXIMA TO L/M70S. TUE SHUD HAVE SOME BREAKS IN
CLOUDS...ALLOWING TEMPS TO REACH AOA 80F MOST RGN...THUS THE BETTER
TSTM CHCS. CONFIDENCE IN AFOREMENTIONED IS LOW...AS GUIDANCE IS NOT
IN AGREEMENT AND ALBERTO IS ESPECIALLY NOT WELL HANDLED BY MODELS
ATTM.
WITH M/ULVL LOPRES S/W OF RGN TUE NGT/WED...SFC TROF AXIS WILL
MEANDER THRU CWA AND GRADUALLY WASH OUT...WITH PLENTY MOISTURE IN
PLACE...CHC POPS WARRANTED. GUIDANCE SUGGESTS THAT ANOTHER NRN
BRANCH TROF WILL BCM DOMINATE ACRS PLAINS THU/FRI...ALLOWING SWLY
FLOW TO ESTABLISH ACRS ERN CONUS. WITH THIS...BERMUDA RIDGE WOULD
BUILD INTO ERN CONUS...TRIGGERING DRIER/WARMER CONDS FOR MID-ATLC
FOR WKS END. STILL...LLVL MOISTURE WILL BE DECENT...SO ISOLATED/SCT
MAINLY DIURNAL CNVCTN CANT BE RULED OUT THRU XTDD FCST.
&&
.AVIATION /13Z SUNDAY THROUGH THURSDAY/...
VFR CONDS TDA. CLDS XPCTD TO BEGIN TO LOWER TNGT...W/ CIGS DROPPING
INTO THE MVFR RANGE OVERNIGHT. IFR CIGS ARE POSSIBLE AS WELL. LGT
RAIN MAY IMPACT THE TERMINALS OVERNIGHT.
SCT/NUM SHWRS/PSBLY TSTMS WILL IMPACT TERMINALS MON THRU WED.
HIGHLY UNCERTAIN AS TO EXTENT OF PREVAILING FLIGHT
RESTRICTIONS...BUT AT LEAST PERIODS OF SUB-VFR CIGS/VBSYS APPEAR
PLAUSIBLE WITH MOIST ELY FLOW IN PLACE. POPS GRADUALLY DIMINISH FOR
SECOND HALF OF WEEK...AS HIPRES BUILDS IN.
&&
.MARINE...
HIGH PRESSURE WILL REMAIN OVER THE WATERS THIS AFTERNOON...BUT LOW
PRESSURE WILL RETROGRADE ONTO THE NORTH CAROLINA COAST INTO
TONIGHT. THE PRESSURE GRADIENT BETWEEN THESE TWO SYSTEMS WILL
CAUSE WIND GUSTS AROUND 20 KNOTS ACROSS THE MIDDLE PORTION OF THE
BAY AND LOWER TIDAL POTOMAC RIVER. A SMALL CRAFT ADVISORY IS IN
EFFECT FOR THESE AREAS THROUGH TONIGHT.
NELY FLOW CONTS MON/TUE. GUSTS ON MON MAY APPROACH SCA
THRESHOLD...BUT CONFIDENCE TO LOW ATTM FOR EXTENSION OF HEADLINES.
LOPRES RMNS IN VICINITY THRU MIDWK...WITH SCT/NUM SHWRS/TSTMS XPCD.
SFC TROF/CDFNT APPROACHES TUE NGT/WED...WITH HIPRES SLOWLY BUILDING
IN THEREAFTER.
&&
.TIDES/COASTAL FLOODING...
WITH PROLONGED ELY FLOW AND LWRG PRESSURE ACRS CHESAPEAKE BAY...
MINOR COASTAL FLOODING LOOKS LIKELY WITH MON MRNGS HIGH TIDE.
FAVORABLE FLOW WILL CONT MON INTO TUE...SO ADDITIONAL COASTAL
FLOODING OF SENSITIVE LOCATIONS IS POSSIBLE AGAIN DURING HIGH
TIDES THIS PERIOD.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ532>534-537-
540>543.
&&
$$
PRODUCTS...LASORSA/WOODY!/SBK
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
704 AM CDT SUN MAY 20 2012
.UPDATE...
UPDATED FOR AVIATION DISCUSSION BELOW.
&&
.DISCUSSION...
/ISSUED 423 AM CDT SUN MAY 20 2012/
RAP H5 ANALYSIS ALONG WITH WATER VAPOR IMAGERY SHOWING NEG TILTED
AND FAIRLY STRONG SHORTWAVE MOVING INTO SRN MN THIS MORNING...THAT
IS FLANKED BY FAIRLY ROBUST RIDGING OVER THE ERN GREAT LAKES AND A
WEAK RIDGE NOW MOVING ACROSS THE ROCKIES. A STRONG UPPER JET AND
DEEP UPPER LOW CAN BE SEEN ACROSS THE NRN PAC THAT IS ON ITS WAY
TOWARD WRN CANADA. AT THE SFC...A COUPLE OF COLD FRONTS WERE
ANALYZED ACROSS THE AREA THIS MORNING. THE MAIN COLD FRONT AT 330
AM STRETCHED FROM NEAR ALBERT LEA UP TO THE ASHLAND...WI
AREA...WITH A SECONDARY COLD FRONT SPLAYED OUT ACROSS MN FROM NEAR
DULUTH TO FARGO. ALONG THE PRIMARY FRONT...THERE IS A SFC
CIRCULATION NEAR ROCHESTER. TO THE WEST OF ALL OF THIS...A
SPRAWLING AREA OF HIGH PRESSURE SITS ON OUR DOORSTEP ACROSS THE
NORTHERN PLAINS.
UPPER LOW MOVING INTO SRN MN WILL BE OVER THE U.P. OF MICH BY
TONIGHT AS IT SLOWLY DE-AMPLIFIES AS IT RUNS INTO THE ERN RIDGE.
UPPER RIDGE CURRENTLY OVER THE ROCKIES WILL SLIP ACROSS THE AREA
MON/TUE AS THE UPPER LOW CURRENTLY IN THE NRN PAC MOVES TO THE BC
COAST AS SIGNIFICANT TROUGH SETS UP OVER THE NRN ROCKIES. THIS
GENERAL TROUGH/RIDGE PATTERN WILL BASICALLY REMAIN IN PLACE INTO
THE HOLIDAY WEEKEND...THOUGH BECOME CONSIDERABLY MORE
AMPLIFIED...WITH H5 HEIGHTS IN SUBTROPICAL RIDGE OVER THE OHIO
VALLEY PEGGED TO RISE ABOVE 590 DM.
AT THE SFC...COLD FRONT LOOKS TO CLEAR THE ERN MPX CWA AROUND
18Z...WITH THE SFC LOW TRACKING FROM RST UP THROUGH EAU. HIGH
PRESSURE WILL QUICKLY MOVE ACROSS THE AREA MONDAY...WITH A STRONG
LEE SIDE LOW EXPECTED TO DEVELOP OVER WRN NODAK TUESDAY. FRONTAL
FEATURE WITH THIS LOW STILL ON TRACK TO MOVE INTO WRN MN
WED...THEN STALL OUT THU NIGHT AS IT RUNS INTO THE AMPLIFYING
RIDGE TO THE SOUTH AND EAST. THE GFS/ECMWF SHOW THIS FRONT HANGING
OUT NEAR THE MPX AREA AS A WARM/STATIONARY FRONT THROUGH THE
WEEKEND...WITH NO STRONG KICKER SYSTEM INDICATED UNTIL MEMORIAL
DAY AT THE EARLIEST.
FOR TODAY THE MAIN ISSUES REVOLVE AROUND MOVING POPS OUT OF THE
AREA...HOW MUCH IF AT ALL DO TEMPS WARM UP OUTSIDE OF WRN MN...AND
HOW STRONG WILL THE WINDS BE THIS MORNING. FOR POPS...THE RAP
SHOWS THE DEFORMATION BAND OF PRECIP FOLLOWING JUST W/NW OF THE
SFC LOW. USED A BLEND OF THE HRRR/GEM/NAM TO CRAWL PRECIP ACROSS
THE AREA...WITH MOST PRECIP OUT OF MN BY 18Z...WITH RAIN CLEARING
EAU/LADYSMITH AROUND 21Z. FOR TEMPS...CONTINUED NORTH
WINDS...COMBINED WITH RAINFALL BEHIND THE COLD FRONT HAS STEADILY
BEAT TEMPERATURES BACK INTO THE 50S ACROSS THE MN PORTION OF THE
CWA...WITH 40S NOT TOO FAR AWAY. GIVEN PREFERENCE FOR HANDLING OF
PRECIP THIS MORNING BY THE GEM/NAM...USED THESE MODELS FOR HIGHS
TODAY...WHICH ENDED UP BEING FAIRLY AGGRESSIVE ON THE COLD SIDE OF
THINGS...WITH HIGHS ONLY AROUND 60 UP THE I-35 CORRIDOR. THIS COULD
BUST IN A BIG WAY IF WE CLEAR OUT FOR A COUPLE OF HOURS THIS
AFTERNOON...BUT CLEARING DOES NOT LOOK TO GET TO THE 35 CORRIDOR
SOON ENOUGH TO ALLOW MUCH OF AN IMPROVEMENT IN TEMPS TODAY. FOR
WRN WI...HIGHS WILL BE ACHIEVED BY 18Z...WITH FALLING TEMPS
EXPECTED THROUGH THE AFTERNOON. AS FOR WINDS...HAVE SEEN SOME 40
TO 50 MPH WINDS GUSTS OVERNIGHT IN CENTRAL MN. THOUGH NOT
EXPECTING ANYTHING LIKE THAT TODAY...THE HRRR DOES SHOW A FAIRLY
TIGHT PRESSURE GRADIENT DEVELOPING ON THE WRN EDGE OF THE SFC LOW
WORKING THROUGH SE MN RIGHT NOW. THE HRRR HAS BEEN DOING PRETTY
GOOD AT PICKING UP THE STRONGER WINDS THROUGH THE NIGHT...SO
LEANED HEAVILY ON IT FOR WINDS THIS MORNING...WITH SOME 20-25 MPH
SUSTAINED NORTH WINDS ACROSS ERN MN THROUGH THE MORNING.
TONIGHT...SFC RIDGE OVER THE HIGHS PLAINS WILL MOVE
OVERHEAD...WITH CLEAR SKIES...CALM WINDS...AND A LOW STARTING
POINT WITH TEMPS THIS EVENING ALL CONSPIRING FOR A RATHER COOL
MORNING ON MONDAY...WITH 40S EXPECTED AND A FEW LOWS IN THE 30S
NOT OUT OF THE QUESTION ACROSS CENTRAL MN. MONDAY WILL BE VERY
PLEASANT...WITH ONLY REAL QUESTION BEING HOW LOW DO DEWPS GO IN
THE AFTERNOON. SOUNDINGS CERTAINLY INDICATE STRONG POTENTIAL FOR
SOME GOOD MIXING OF DRIER AIR TO THE SFC AND FAVORED DEWPS MONDAY
TOWARD THE MUCH DRIER MET.
FOR MONDAY NIGHT...STRONG WAA WILL BE COMING IN ALOFT OUT AHEAD OF
THE SYSTEM DEVELOPING OVER THE WRN DAKOTAS. 20.00 GFS GENERATES
SOME ELEVATED THUNDERSTORMS IN WRN MN MON NIGHT IN THIS WAA...BUT
QUICK LOOK AT SOUNDINGS AND RH HEIGHT PROFILES SHOWS ATMO BELOW
10K FT BEING QUITE DRY...SO KEPT THE FORECAST DRY WITH THE
EXPECTATION OF ANOTHER GOOD ROUND OF ACCUS/VIRGA BREAKING OUT. OF
COURSE WITH THAT WAA...A SIGNIFICANT WARM TONGUE AT H85 IS
FORECAST BY ALL MODELS TO COME INTO WRN MN...WITH TEMPS BETWEEN 16
AND 18C NOTED. LAST WEEK THIS RESULTED IN HIGHS IN THE 90S AND
THERE IS GUIDANCE SHOWING PLACES LIKE MADISON GETTING BACK INTO
THE 90S TUESDAY. HOWEVER...THE WARM FRONT SHOULD STAY OFF TO OUR
SW...SO NOT FEELING CONFIDENT IN 90S OCCURRING AGAIN...BUT DID BUMP
WRN MN UP INTO THE MID/UPPER 80S.
AFTER THAT...WHAT LOOKS LIKE A GOOD BET IS ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS WED AFTERNOON INTO THU AS ANOTHER COLD
FRONT MOVES IN. THERE ARE TIMING DIFFERENCES WITH THIS
FRONT...WITH THE GFS SHOWING MORE WED/WED NIGHT WHILE THE ECMWF IS
MORE WED NIGHT/THU. EITHER WAY...DOES LOOK LIKE ANOTHER GOOD SHOT
AT SOME HEALTHY RAINS AS THE FRONT STALLS OUT OVER/NEAR MN
THURSDAY. BEYOND THURSDAY...CONFIDENCE DECREASES QUITE A BIT ON
THE FORECAST AS THE GFS/ECMWF DIFFER ON WHERE TO PLACE THE
STATIONARY/WARM FRONT FRIDAY RIGHT THROUGH MEMORIAL DAY. GIVEN THE
STRENGTHENING RIDGE TO THE SOUTH AND EAST OVER NEXT WEEKEND...THE
FRONT COULD CERTAINLY BE A BREEDING GROUND FOR SEVERAL ROUNDS OF
THUNDERSTORMS AS MOISTURE RIDES UP OVER IT. IF WE EVER END UP ON
THE SOUTH END OF THE FRONT NEXT WEEKEND...RECORD TEMPS CERTAINLY
LOOK LIKE A POSSIBILITY AS H85 TEMPS ARE PROGGED TO GET UP INTO
THE MID/UPPER 20S C OVER THE CENTRAL PLAINS. THE 20.00
ECMWF/GFS...BOTH SHOW THIS FRONT WELL SOUTH OF THE AREA
FRIDAY...WITH IT SLOWLY LIFTING TO NORTH OF THE MPX AREA BY
SUNDAY.
&&
.AVIATION.../12Z TAF ISSUANCE/
MAIN ISSUES WILL BE THUNDER IN WISCONSIN AND IFR/MVFR CEILINGS IN
MN AND EVENTUALLY WISC. FRONT IS MAKING VERY SLOW PROGRESS. STILL
ONLY AT KRNH NOW AND SEEMS LIKE THE SLOWER APPROACH WILL BE
CORRECT. THUS WILL NOT BRING IT TO KEAU UNTIL EARLY AFTERNOON AND
WILL INTRODUCE ANOTHER ROUND OF THUNDER AT KEAU AT 17Z. FIRST
BATCH OF STORMS THERE NOW AND WILL MENTI0N TSRA FOR AN HOUR OR SO.
OTHER CONCERN IS MVFR/IFR CEILINGS IN RAIN-COOLED AIR.
KSTC/KRWF/KMSP ALL IFR AT THIS TIME AND EXPECT KAXN WILL GO IFR
WITH RAIN AT THEIR DOORSTEP. ONCE DEFORMATION RAIN DEPARTS AND/OR
WEAKENS... CEILINGS SHOULD SCATTER OUT LATE THIS AFTERNOON.
KMSP...
IFR CEILINGS ACROSS THE ENTIRE METRO AS WELL AS SOUTH/WEST/NORTH
OF KMSP. WITH FRONT OVER THE EASTERN METRO THERE HAVE BEEN POCKETS
OF CLEARING AND SOME SITES HAVE SEEN THEIR VISIBILITY DROP TO IFR
IN THE LAST HOUR. LAKE ELMO IS EVEN AT 1/4SM. KMSP IS NOT AS PRONE
TO FOG AS SOME OF THE EASTERN METRO AIRPORTS BUT THIS WILL NEED TO
BE WATCHED CLOSELY. OTHERWISE...THUNDER THREAT IS TO THE EAST AND
IT IS MAINLY A MATTER OF TIMING FOR THE IFR CEILINGS TO IMPROVE TO
MVFR AND THEN SCATTER OUT LATER THIS AFTERNOON.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/TDK
AREA FORECAST DISCUSSION
NWS HASTINGS NE
550 AM CDT SUN MAY 20 2012
.AVIATION...12Z KGRI TAF. VFR CONDITIONS TO CONTINUE THROUGH THE
NEXT 24 HOURS. SATELLITE IMAGERY INDICATES SKIES ARE CLEARING OUT
ACROSS SOUTH CENTRAL NEBRASKA...WITH CLEAR SKIES EXPECTED BY 15Z.
SURFACE WINDS WILL REMAIN FROM THE NORTH/NORTHWEST BUT WEAKEN
THROUGH THE DAY...BECOMING LIGHT AND VARIABLE OVERNIGHT. VISIBILITY
RESTRICTIONS ARE NOT EXPECTED THROUGH THE NEXT 24 HOURS.
&&
.PREV DISCUSSION... /ISSUED 440 AM CDT SUN MAY 20 2012/
SHORT TERM...THROUGH TUESDAY NIGHT. OFFICIALLY...THE FORECAST
REMAINS DRY THROUGH THESE 72 HOURS. HOWEVER...THIS WILL NEED
WATCHED CLOSELY AS THERE ARE AT LEAST A FEW OPPORTUNITIES FOR
THUNDERSTORMS TO POTENTIALLY SNEAK INTO THE FORECAST. OF HIGHER
CONFIDENCE IS POSSIBLE ADVISORY-CRITERIA WINDS ON TUESDAY.
08Z OBJECTIVE SURFACE ANALYSIS PLACES THE CWA BETWEEN A 1010MB LOW
OVER WESTERN IA...AND A 1021MB HIGH STRETCHED NORTH-SOUTH ACROSS
THE PANHANDLE INTO EASTERN CO. AS A RESULT...BREEZES EARLY THIS
MORNING ARE LARGELY FROM THE WEST-NORTHWEST AREA WIDE...BUT
RANGING FROM VERY LIGHT IN THE FAR WESTERN COUNTIES...TO GUSTS
STILL AROUND 20 MPH IN THE EAST WHERE THE GRADIENT REMAINS
TIGHTEST. WATER VAPOR IMAGERY CLEARLY DEPICTS THE DEPARTING
SHORTWAVE RESPONSIBLE FOR YESTERDAY/S ROUND OF SEVERE WEATHER NOW
OVER NORTHEAST NEB...WITH BROAD QUASI-ZONAL FLOW ALOFT EXTENDING
BACK UPSTREAM TO THE EASTERN PACIFIC. RADAR AND 11-3.9 MICRON
SATELLITE IMAGERY CONFIRMS A STUBBORN AREA OF LINGERING LIGHT RAIN
THAT HAS FINALLY PUSHED OUT OF THE NORTHEASTERN CWA...IN ASSOCIATION
WITH THE PARENT AREA OF MID LEVEL CONVERGENCE/SATURATION ON THE
BACKSIDE OF THE EXITING SHORTWAVE. MEANWHILE...OFF TO THE SOUTH A
VERY NARROW BAND OF LIGHT RAIN/SPRINKLES IS MAKING ITS WAY ACROSS
PARTS OF CENTRAL KS...LIKELY DUE TO SOME SUBTLE MID LEVEL
FRONTOGENESIS IN THE ENTRANCE REGION OF A MID-UPPER JET STREAK
PULLING ACROSS NORTHERN KS/SOUTHEAST NEB.
FOLLOWING THE 05Z HRRR REFLECTIVITY CLOSELY...ALONG WITH LATEST
RADAR TRENDS...LOOKS LIKE ANY SPRINKLES IN NEB ZONES SHOULD
PRETTY MUCH BE GONE BY SUNRISE...SO WILL NOT CARRY A PRE-FIRST
PERIOD ZONE ISSUANCE TO COVER IT. AS FOR THE KS SPRINKLES...NOT
EXPECTING THESE TO BE AN ISSUE PAST SUNRISE EITHER...BUT WILL
CARRY A SLIGHT CHANCE SPRINKLE MENTION ACROSS THE FAR SOUTHERN CWA
THROUGH 12Z JUST IN CASE SOMETHING SNEAKS IN. OTHERWISE...A DRY
AND SEASONABLY PLEASANT DAY IS IN STORE. ALOFT...THE DEPARTING
SHORTWAVE AXIS WILL BE WELL UP INTO WESTERN WI BY 00Z...WITH
BROAD...MODESTLY AMPLIFIED RIDGING EXTENDING FROM THE WEST COAST
TO CENTRAL PLAINS IN ITS WAKE. AT THE SURFACE...A RIDGE AXIS WILL
GRADUALLY PASS ACROSS THE CWA THROUGH THE DAY...TRANSITIONING
WINDS FROM NORTHERLY THROUGH MUCH OF THE DAY TO MORE EASTERLY BY
DAY/S END. WITH THIS CENTER OF THIS HIGH TO THE NORTH OF THE AREA
THIS MORNING...THERE SHOULD BE AN INCREASE IN WIND SPEEDS MOST
AREAS AS BOUNDARY LAYER MIXING COMMENCES...WITH SUSTAINED SPEEDS
EASILY 10-15 MPH FOR SEVERAL HOURS...BEFORE SUBSIDING A BIT DURING
THE AFTERNOON. ALTHOUGH COULD SEE SOME LINGERING CLOUDS THIS
MORNING...AND MAYBE EVEN SOME DAYTIME FAIR WEATHER CUMULUS
DEVELOPMENT MAINLY IN EASTERN ZONES...THE CWA AS A WHOLE SHOULD
AVERAGE MOSTLY SUNNY TODAY. AS A RESULT...ANTICIPATE A FAIRLY
EFFICIENT WARM UP...AND KEPT HIGHS SIMILAR TO PREVIOUS
FORECAST...AND FAVORING THE WARMER MET GUIDANCE/RAW NAM SOLUTION
VERSUS COOLER MAV/GFS. THUS HAVE THE MAJORITY OF THE CWA REACHING
THE 72-76 RANGE.
TONIGHT...THE BROAD WESTERN TO CENTRAL CONUS RIDGE AMPLIFIES A
BIT...WITH MODEST MID LEVEL HEIGHT RISES OVER THE CENTRAL PLAINS
AS THE UPPER LEVEL FLOW BECOMES MORE NORTHERLY VERSUS WESTERLY
AROUND THE EASTERN PERIPHERY OF THE RIDGE. ALTHOUGH HAVE LEFT ALL
THUNDERSTORM MENTION OUT OF THE FORECAST FOR NOW...WILL HAVE TO KEEP
A CLOSE EYE ON FAR NORTHWEST ZONES AFTER MIDNIGHT AND ESPECIALLY
TOWARD SUNRISE...AS BOTH THE NAM/GFS ADVERTISE MODEST ELEVATED
THETA-E ADVECTION EVIDENT AT 700MB PUSHING EAST OUT OF WESTERN
NEB...ALONG WITH MAYBE UP TO A FEW HUNDRED J/KG MUCAPE ROOTED IN
THE 850-700MB LAYER. BOTH OF THESE MODELS KEEP CONVECTIVE QPF AT
LEAST SLIGHTLY NORTHWEST OF THE CWA OVER THE SANDHILLS...AND THE
00Z 4KM WRF-NMM SHOWS LITTLE HINT OF DEVELOPING CONVECTION...BUT
THIS WILL NEED CLOSELY WATCHED AS THIS KIND OF FORCING OFTEN LEADS
TO CLASSIC SUNRISE SURPRISE SHOWERS/WEAK STORMS. FOR LOW TEMPS
TONIGHT...WITH GENERALLY LIGHT EAST-SOUTHEAST BREEZES AND MOSTLY
CLEAR SKIES...OPTED TO LOWER LOWS 1-3 DEGREES FROM PREVIOUS
FORECAST...WITH MOST AREAS BETWEEN 44-48.
MONDAY...RIDGING WILL CONTINUE TO DOMINATE THE MID/UPPER
LEVELS...WITH THE AXIS GENERALLY ALIGNED ALONG THE ROCKIES...AND
CONTINUED NORTH-NORTHWEST FLOW ALOFT OVER THE CENTRAL PLAINS. AS
THE SURFACE RIDGE AXIS DEPARTS FARTHER EAST AND MODEST PRESSURE
FALLS OCCUR OVER THE HIGH PLAINS...SOUTHERLY WINDS WILL BECOME
ESTABLISHED...AND UPPED SUSTAINED SPEEDS SLIGHTLY WITH MOST OF THE
CWA SOLIDLY INTO THE 15-20 MPH RANGE MUCH OF THE DAY. DESPITE
MODEST LOW LEVEL MOISTURE RETURN WITH SURFACE DEWPOINTS POSSIBLY
APPROACHING 50 ACROSS THE WESTERN CWA...THE PRIMARY LOW LEVEL
INSTABILITY AXIS SHOULD SET UP AT LEAST 1-2 COUNTIES WEST OF THE
CWA DURING THE AFTERNOON...WITH THE NAM KEEPING ANY LATE AFTERNOON
CONVECTION SAFELY NORTHWEST OF THE AREA ACROSS THE SANDHILLS.
ASSUMING THAT NO SHOWERS/WEAK STORMS DO IN FACT DEVELOP EARLY IN
THE MORNING AS DISCUSSED ABOVE...HAVE FAIRLY HIGH CONFIDENCE IN
LEAVING STORMS OUT THROUGH THE AFTERNOON HOURS...DESPITE SPC
ASSIGNING A GENERAL THUNDER AREA TO MUCH OF THE WESTERN CWA ON THE
DAY2 OUTLOOK. WITH SOUTHERLY FLOW AND AFTERNOON MIXING TO AROUND
800MB PER NAM SOUNDINGS...KEPT HIGH TEMPS SIMILAR TO PREVIOUS
FORECAST...AND GENERALLY 2-4 DEGREES ABOVE MET/MAV GUIDANCE
CONSENSUS...WITH MOST AREAS 79-82.
MONDAY NIGHT...THE MID/UPPER RIDGE AXIS BECOMES MORE POSITIVELY
TILTED AND EXTENDS DIRECTLY THROUGH THE CENTRAL PLAINS...AS THE
RIDGE STARTS ITS EASTWARD PUSH IN RESPONSE TO AN INCOMING
SHORTWAVE AND ASSOCIATED UPPER JET STREAK MOVING INTO THE PACIFIC
NORTHWEST. ASSUMING THAT NO SANDHILLS CONVECTION SNEAKS INTO THE
CWA DURING THE EVENING...WILL STAY THE COURSE WITH A STORM-FREE
FORECAST THROUGH THE NIGHT...ALTHOUGH THIS WILL ALSO BEAR WATCHING
AS BOTH THE NAM/GFS ADVERTISE A BATCH OF ELEVATED INSTABILITY ON
THE ORDER OF 500-1000 J/KG SLIDING EAST OVER THE CWA DURING THE
NIGHT. THINKING AT THIS POINT IS THAT THESE PARCELS SHOULD REMAIN
CAPPED IN THE PRESENCE OF VERY LITTLE UPPER FORCING...WITH BETTER
CONVERGENCE ALONG THE NOSE OF THE LOW LEVEL JET AIMED MORE INTO
THE OAX CWA TOWARD THE MO RIVER...WHERE THE NAM ACTUALLY DOES
DEVELOP SOME CONVECTIVE QPF. CERTAINLY CANNOT COMPLETELY RULE OUT
A FEW SHOWERS/STORMS FLARING UP AND LATER SHIFTS MAY HAVE TO
CONSIDER ADDING A SLIGHT POP SOMEWHERE.
TUESDAY...INSTABILITY INCREASES FURTHER...AS SURFACE DEWPOINTS
CLIMB BACK INTO THE LOW-MID 50S...BUT WITH INCOMING NORTHWEST
CONUS SHORTWAVE REMAINING TO THE WEST...THIS SHOULD BE NOTHING
MORE THAN A WARM AND RATHER WINDY DAY...WITH NEAR-SURFACE PARCELS
CAPPED OFF AS SUGGESTED BY 700MB TEMPS INTO THE 11-13C RANGE. ANY
LATE AFTERNOON STORMS THAT MIGHT MANAGE TO DEVELOP IN THE REGION
SHOULD FOCUS WEST OF THE CWA NEARER THE PRIMARY SYNOPTIC DRYLINE.
AS A RESULT...EXPECT THE BIG STORY TUESDAY TO BE STRONG SOUTHERLY
WINDS...AS BOTH THE NAM/GFS DEEPEN A 989-992MB LOW OVER THE HIGH
PLAINS OVER THE COURSE OF THE DAY. THE RESULTANT STRENGTHENING
PRESSURE GRADIENT...ALONG WITH MIXING TO AT LEAST 750MB MOST
AREAS...SHOULD REALLY GET SOUTHERLY WINDS GOING. PREVIOUS FORECAST
ALREADY HAD PARTS OF THE AREA REACHING ADVISORY CRITERIA OF
SUSTAINED 30 MPH...AND GENERALLY KEPT THIS THEME INTACT...WITH THE
HIGHEST SPEEDS FOCUSED ACROSS THE WESTERN 1/2 OF THE CWA. WITH
THIS STILL BEING 5 PERIODS OUT...WAY TOO EARLY FOR A
HEADLINE...BUT WILL CONTINUE TO HIGHLIGHT IN THE HAZARDOUS WEATHER
OUTLOOK. EXPECTING MINIMAL CLOUD COVER...THIS SHOULD BE A CLASSIC
BIG WARM UP...DECENT DEWPOINT MIX-DOWN KIND OF DAY...AND HAVE
DEWPOINTS FALLING A BIT IN THE AFTERNOON...ESPECIALLY WEST. TEMP
WISE...NUDGED UP HIGHS 2-3 DEGREES FROM PREVIOUS FORECAST MOST
AREAS...AIMING FOR 89-92 MOST AREAS...AND EVEN MID 90S SOUTHWEST.
ALTHOUGH THIS IS SEVERAL DEGREES ABOVE MET/MAV GUIDANCE
CONSENSUS...IT IS MORE IN LINE WITH RAW NAM TEMPS...AND DAYS LIKE
THIS HAVE PROVEN SEVERAL TIMES IN THE PAST FEW WEEKS THAT WARMER
IS THE WAY TO GO.
TUESDAY NIGHT...YET AGAIN KEPT THE AREA FREE OF STORM
MENTION...DESPITE THE GFS TRYING TO SNEAK SOME ACTIVITY INTO
NORTHEAST ZONES AFTER MIDNIGHT. DESPITE INCREASING FORCING FROM
THE INCOMING SHORTWAVE...MOST OF THIS ENERGY WILL REMAIN BACK OVER
THE NORTHERN ROCKIES/NORTHERN PLAINS...AND BESIDES BOTH THE
NAM/GFS ADVERTISE A CONSIDERABLE CAPPING INVERSION WITH A 700MB
THERMAL RIDGE OF 13C+ SETTING UP OVER THE CWA DURING THE NIGHT.
NOT SURPRISINGLY...MODEL CONSENSUS IS TO FOCUS CONVECTION NORTH OF
THE CWA THROUGH THE NIGHT...NEAR AND JUST BEHIND AN INCOMING
SURFACE COLD FRONT AND IN AREA OF SLIGHTLY COOLER MID LEVEL TEMPS.
WILL HAVE TO IRON OUT SOME DETAILS REGARDING THE SPEED OF THIS
INCOMING COLD FRONT HOWEVER...AS BY 12Z WEDNESDAY THE NAM ALREADY
HAS THE FRONT INTO THE WESTERN CWA...WHILE THE ECMWF STILL HAS IT
BACK IN WESTERN NEB. IF ANY STORMS DO MANAGE TO DEVELOP INTO THE
NORTHERN CWA DURING THE NIGHT...STRONG TO SEVERE IS CERTAINLY
POSSIBLE...BUT CONFIDENCE STILL REMAINS LOW ENOUGH REGARDING
STORM DEVELOPMENT TO KEEP POPS BELOW THE 20 PERCENT SLIGHT CHANCE
THRESHOLD.
LONG TERM...TARTING 12Z WEDNESDAY. GUIDANCE FROM THE OPERATIONAL
GFS AND EC SUGGEST A MID LEVEL SHORT WAVE...PERHAPS A CLOSED LOW
PER THE GFS...WILL PUSH ACROSS THE NORTHERN PLAINS AND SOUTH
CENTRAL CANADA WEDNESDAY AND THURSDAY. AN ASSOCIATED SURFACE LOW
IS ALSO EXPECTED TO PUSH EAST ACROSS THE NORTHERN PLAINS AND SOUTH
CENTRAL CANADA THUS ALLOWING A LOW LEVEL BAROCLINIC ZONE TO PUSH
ACROSS OUR AREA DURING THE DAY WEDNESDAY. SURFACE RIDGING IS THEN
EXPECTED TO INFILTRATE THE CENTRAL PLAINS LATE WEDNESDAY THROUGH
EARLY FRIDAY BEFORE LOW LEVEL RETURN FLOW IS REALIZED ACROSS OUR
AREA LATE FRIDAY INTO SATURDAY.
THE OPERATIONAL GFS AND EC BOTH CONTINUE TO INDICATE CONVECTION
ALONG THE LOW LEVEL BAROCLINIC ZONE WEDNESDAY AFTERNOON AND EVENING.
THE OPERATIONAL GFS IS BECOMING SOMEWHAT MORE PROGRESSIVE AND NOW
SUGGESTS CONVECTION WILL FIRE EAST OF OUR CWA WELL AFTER THE LOW
LEVEL BAROCLINIC ZONE HAS CLEARED OUR AREA. THE EC ON THE OTHER HAND
SUGGESTS A SLIGHTLY SLOWER FROPA WITH CONVECTION POSSIBLE ALONG THE
EASTERN HALF OF OUR CWA LATE WEDNESDAY AFTERNOON INTO WEDNESDAY
EVENING. WITH 0-1KM MLCAPE VALUES PERHAPS APPROACHING 1500J/KG AND
DEEP LAYER BULK SHEAR VALUES IN THE NEIGHBORHOOD OF 40KTS...LARGE
HAIL AND PERHAPS STRONG WINDS CANNOT BE RULED OUT SHOULD
CONVECTION BE REALIZED OVER OUR AREA ALONG THE LOW LEVEL BAROCLINIC
ZONE WEDNESDAY. OPTED TO PLAY IT SAFE SINCE THE EC CONTINUES TO
SUGGEST THIS POSSIBILITY AND KEPT CONVECTION IN THE FORECAST ACROSS
THE EASTERN HALF OF THE CWA...WITH A SEVERE MENTION ALSO IN THE HWO
FOR LATE WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING.
MID AND UPPER LEVEL JET ENERGY IS EXPECTED TO PUSH OVERHEAD
THE CENTRAL PLAINS LATE WEDNESDAY...WITH THE LEFT-FRONT QUAD OF A
60-70KT MID LEVEL JET STREAK EXPECTED TO SET UP SHOP OVER OUR AREA
WEDNESDAY NIGHT INTO THURSDAY MORNING. AN INDIRECT THERMAL
CIRCULATION MAY PRODUCE ENOUGH LIFT FOR PRECIPITATION
PRODUCTION...ASSUMING ENOUGH LOW TO MID LEVEL MOISTURE...AND QPF
FIELDS FROM THE OPERATIONAL GFS AND EC BOTH SUGGEST PRECIPITATION
WILL BE REALIZED WEDNESDAY NIGHT/THURSDAY MORNING. WENT AHEAD WITH
POPS LATE WEDNESDAY INTO EARLY THURSDAY AS A RESULT. THE RIGHT-REAR
QUADRANT OF THE SAME MID LEVEL JET STREAK IS THEN EXPECTED TO PUSH
OVER NORTHERN PORTIONS OF THE CWA THURSDAY NIGHT INTO FRIDAY
MORNING...THUS BRINGING ANOTHER CHANCE FOR PRECIPITATION TO NORTHERN
PORTIONS OF OUR AREA. THE INTRODUCTION OF A ~40KT LOW LEVEL JET
STREAK WILL THEN BRING FURTHER CHANCES OF PRECIPITATION TO THE AREA
FRIDAY NIGHT INTO EARLY SATURDAY. BEYOND WEDNESDAY EVENING...LOW
LEVEL MOISTURE IS NOT OVERLY IMPRESSIVE AS SURFACE RIDGING REMAINS
ENTRENCHED ACROSS THE AREA AND AS A RESULT...INSTABILITY SUFFERS
GREATLY. LOW LEVEL MOISTURE FINALLY IMPROVES BY LATE FRIDAY AS LOW
LEVEL RETURN FLOW IS REALIZED ACROSS THE AREA...WITH DEEP LAYER
MUCAPE VALUES PERHAPS CLIMBING TO AROUND 1000J/KG BY FRIDAY NIGHT.
GIVEN ALL THIS...AM NOT INCLINED TO GO WITH ANY SEVERE WORDING IN
THE HWO BEYOND WEDNESDAY EVENING.
A SUBTLE COOLING TREND SHOULD BE NOTED ACROSS THE AREA WEDNESDAY AND
THURSDAY AS SURFACE RIDGING REMAINS OVER THE AREA. LOW LEVEL RETURN
FLOW AND RESULTANT LOW LEVEL WARM AIR ADVECTION WILL THEN PROMOTE A
WARMING TREND TO FINISH OUT THE EXTENDED FORECAST PERIOD. DESPITE
ANY TRENDS...TEMPERATURES DURING THE EXTENDED FORECAST PERIOD WILL
REMAIN AT NEAR OR ABOVE-NORMAL LEVELS FOR THIS TIME OF YEAR.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
AVIATION/LONG TERM...BRYANT
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1006 AM CDT SUN MAY 20 2012
.UPDATE...LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW
SURFACE LOW PRESSURE MOVING ACROSS WESTERN WISCONSIN AND ITS
TRAILING COLD FRONT EXTENDING SOUTHWEST OVER EASTERN IOWA AND
CENTRAL MISSOURI. ELEVATED CONVECTION IS ONGOING OVER N-C
WISCONSIN IN THE DIVERGENCE REGION AHEAD OF A DECENT LOOKING
SHORTWAVE WHICH IS MOVING NORTHEAST OVER MINNESOTA. MOSTLY CLEAR
SKIES EXIST OVER MUCH OF EASTERN WISCONSIN WHERE TEMPS ARE ALREADY
IN THE LOWER 80S.
THE STORMS NEAR HAYWARD AND MEDFORD WILL PUSH ACROSS NORTH-CENTRAL
WISCONSIN LATER THIS MORNING. MEANWHILE...SURFACE LOW PRESSURE
WILL MOVE NORTHEAST...FROM ABOUT WAUSAU TO IRON MOUNTAIN THIS
AFTERNOON. FURTHER SURFACE DESTABILIZATION ALONG WITH LARGE SCALE
ASCENT VIA SHORTWAVE AND UPPER DIVERGENCE POINTS TOWARDS SURFACE
BASED CONVECTION DEVELOPING EARLY THIS AFTERNOON. BEST GUESS AT
THE MOMENT IS FROM IRON MOUNTAIN TO WAUSHARA CORRIDOR...THEN
TRANSLATING EAST THROUGH THE AFTERNOON. AN 83/61 SURFACE PARCEL
WILL YIELD ABOUT 1700 J/KG OF ML CAPE. DEEP LAYER UNI-DIRECTIONAL
SHEAR OF 25-30 KTS (UP TO 35 KTS OVER FAR NE WISCONSIN) SUPPORTS
ISOLATED TO SLIGHT RISK CHANCES OF SEVERE THUNDERSTORMS. DAMAGING
WIND GUSTS AND LARGE HAIL WILL CONTINUE TO BE THE PRIMARY THREATS.
IF SURFACE WINDS CAN REMAINED BACK OVER FAR NE WISCONSIN DUE TO A
LAKE COMPONENT...MAY ALSO SEE AN ISOLATED TORNADO THREAT DEVELOP...BUT
NOT CONFIDENT IN THIS OCCURRING. THE FRONT STILL LOOKS TO EXIT
EARLY THIS EVENING SO THINK MOST OF THE ACTION WILL OCCUR BEFORE
THAT TIME.
MPC
&&
.PREV DISCUSSION...ISSUED AT 647 AM CDT SUN MAY 20 2012...
SHORT TERM...TODAY THROUGH MONDAY...PCPN TRENDS...THE THREAT OF
SVR TSTMS AND HEAVY RAINFALL THIS AFTERNOON AND EVG...AND TEMPERATURES
ARE THE MAIN FCST CONCERNS.
A COLD FRONT WAS SITUATED FROM WSTRN LK SUP SWWD THROUGH NW WI...
SE MN AND IA. WEAK LOW PRESSURE WAS LIFTING NE ALONG THIS BOUNDARY...
WITH ONE CIRCULATION NEAR MSP AND ANOTHER IN CENTRAL IA. WV IMAGERY
SHOWED A POTENT S/W TROF MOVG THROUGH EASTERN SD/NE...AND HEADED
TOWARD THE WSTRN GREAT LKS. IN ADDITION...THE RRQ OF AN UPPER JET
WAS SITUATED OVER THE UPPER MISS VALLEY...AND WAS PROVIDING THE
FORCING FOR A LARGE AREA OF POST-FRONTAL SHOWERS AND TSTMS OVER
EASTERN SD AND MN. MOISTURE WAS POOLING NEAR THE COLD FRONT...WITH
DEW POINTS IN THE MID 50S TO LOWER 60S. 00Z SOUNDINGS SHOWED PCPN
WATER VALUES 200 PERCENT OF NORMAL OVER MN.
THE COLD FRONT WILL EDGE EAST DURING THE DAY...AS THE S/W TROF
APPROACHES FROM THE SOUTHWEST AND THE RRQ OF THE UPPER JET
POSITIONS ITSELF OVER GRB CWA DURING THE AFTERNOON. PRECIPITABLE
WATER VALUES ARE EXPECTED TO INCREASE TO 150-200 PERCENT OF
NORMAL...WITH SFC DEW POINTS INCREASING INTO THE UPPER 50S AND
LOWER 60S...AND H8 DEW POINTS AROUND 10-12 C. ALTHOUGH MID-LEVEL
CLOUDS WILL LIMIT HEATING TO SOME DEGREE...FILTERED SUNSHINE
SHOULD ALLOW TEMPS TO WARM INTO THE LOW TO MID 80S IN NE/EC WI...
BOOSTING CAPES TO 1500-2000 J/KG THIS AFTERNOON. THE COMBINATION
OF STRONG DYNAMIC FORCING...ABUNDANT MOISTURE AND MODERATE
INSTABILITY SUPPORTS WIDESPREAD SHOWER/TSTM DEVELOPMENT LATER THIS
MORNING AND AFTERNOON. LIKELY POPS ARE WARRANTED OVER THE ENTIRE
CWA...AND HAVE BOOSTED POPS TO CATEGORICAL OVER NC WI. INGREDIENTS
ARE IN PLACE FOR HEAVY RAINFALL...AND A HANDFUL OF REPORTS OF AN
INCH OR GREATER HAVE ALREADY BEEN REPORTED UPSTREAM...INCLUDING A
4+ INCH AMOUNT IN NW IA. HAVE ADDED THE MENTION OF HEAVY RAINFALL
TO THE GRIDS/ZFP. SPC ALSO HAS MUCH OF C/NE/EC WI IN A SLGT RISK
TODAY. NOT CONFIDENT ENOUGH TO MENTION THIS EXPLICITLY IN THE
FCST...DUE TO CONCERNS ABOUT CLOUD COVER...BUT WILL MENTION AT
LEAST AN ISOLD THREAT OF DAMAGING WINDS AND HAIL IN THE HAZARDOUS
WEATHER OUTLOOK. WENT WITH A NON- DIURNAL TEMPERATURE TREND IN THE
GRIDS DUE TO THE FRONTAL PASSAGE/PCPN.
WILL HAVE A DECREASING TREND IN THE PCPN THIS EVG AS THE FRONT
EXITS THE REGION...WITH PARTIAL CLEARING OCCURRING OVERNIGHT.
STAYED CLOSE TO THE PREVIOUS FCST FOR MIN TEMPS...MAINLY 40S AND
LOWER 50S.
ON MONDAY...PARTLY CLOUDY SKIES AND MIXING THROUGH 800-775 MB
SHOULD YIELD MAX TEMPS IN THE UPPER 60S AND LOWER 70S...CLOSER
TO NORMAL.
LONG TERM...MONDAY NIGHT THROUGH SATURDAY.
A QUIET PATTERN EXPECTED MONDAY NIGHT AND TUESDAY AS CANADIAN
HIGH PRESSURE DOMINATES THE WEATHER PATTERN. A COMBINATION OF CLEAR
SKIES...LIGHT WINDS AND DEW POINTS IN THE 30S MONDAY NIGHT WILL
ALLOW TEMPERATURES TO FALL CONSIDERABLY LOWER THAN PREVIOUS FORECAST.
DID LOWER THEM SEVERAL DEGREES AND ALSO MENTIONED AREAS OF FROST
ACROSS THE NORTH. TUESDAY WILL BE SUNNY AND MILD WITH HIGHS IN
THE UPPER 60S TO MIDDLE 70S. THE HIGH WILL SLIDE EAST OF THE
AREA TUESDAY NIGHT AND WEDNESDAY. SOUTHERLY FLOW WILL ALLOW FOR
WARMER TEMPERATURES TO WORK INTO THE AREA.
THE NEXT SYSTEM WILL AFFECT THE AREA FROM LATE WEDNESDAY NIGHT INTO
THURSDAY AND THURSDAY NIGHT. HAVE A HIGH CHANCE FOR SHOWERS AND
THUNDERSTORMS THURSDAY AND THURSDAY NIGHT.
MODEL DIVERGE ON THE DETAILS OF A BUILDING 500MB RIDGE FRIDAY THROUGH
THE MEMORIAL DAY WEEKEND. 00Z GFS NOW HAS THE FRONT WELL SOUTH OF
THE AREA AND TEMPERATURES WOULD BE SOMEWHAT ABOVE NORMAL DESPITE
BEING ON THE COOL SIDE OF THE BOUNDARY. THE ECMWF ON THE OTHER HAND...
HAS THE BOUNDARY LURKING ACROSS THE STATE WITH PERIODIC CHANCES
FOR SHOWERS AND THUNDERSTORMS AS COMPLEXES OF STORMS ROLL ACROSS
THE STATE. THE ECMWF WOULD BE CONSIDERABLY WARMER THAN THE GFS.
THE CANADIAN TRENDED TOWARD THE ECMWF WITH 500MB HEIGHTS...BUT
BOUNDARY WAS JUST TO THE SOUTH OF THE AREA. DID NOT MAKE MANY
CHANGES TO THE FRIDAY AND SATURDAY PERIOD FOR NOW DUE TO THE
DIFFERENCES ON HOW THE MODELS HANDLE THE UPPER LEVEL/SURFACE
FEATURES.
&&
.AVIATION...A COLD FRONT AND UPPER LEVEL DISTURBANCE WILL BRING
INCREASING SHOWER AND THUNDERSTORM ACTIVITY TO THE REGION TODAY.
THE BEST BET FOR TSTMS WILL BE LATE MORNING TO MID-AFTERNOON FOR
RHI/CWA/AUW...AND MID-AFTERNOON TO EARLY EVG AT GRB/ATW. MVFR/IFR
CONDITIONS ARE EXPECTED WITH THE TSTMS...ALONG WITH HEAVY RAINFALL
AND THE POTENTIAL FOR ISOLD SVR STORMS. PCPN SHOULD TAPER OFF
DURING THE EVG. IN THE WAKE OF THE COLD FRONT...MORE WIDESPREAD
MVFR/IFR CIGS ARE EXPECTED TO SPREAD ACROSS THE REGION. IN
ADDITION...SOME LLWS MAY DEVELOP AT RHI/AUW/CWA BY MID TO LATE
EVG..AS NORTH WINDS INCREASE TO AROUND 40 KTS AT ABOUT 1500 FEET
AGL.
KIECKBUSCH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
308 PM CDT SUN MAY 20 2012
...UPDATED LONG TERM SECTION...
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 335 AM CDT SUN MAY 20 2012
THE LATEST NAM AND RUC MODEL GUIDANCE SHOWS THE BAND OF 700 MILLIBAR
FRONTOGENETIC FORCING ACROSS FAR WESTERN KANSAS EARLY THIS MORNING.
THE MODELS MOVE THIS AREA OF FORCING EASTWARD AND WEAKEN IT
THROUGH SUNRISE. GIVEN THE GOING RADAR TRENDS, EXPECT THE
PRECIPITATION TO BE MOVING OUT OF WESTERN KANSAS AND THROUGH
CENTRAL KANSAS BY 12Z AS THE FORCING MOVES EAST AND WEAKENS.
WINDS HAVE BECOME LIGHT AND VARIABLE AS THE BOUNDARY LAYER
DECOUPLED THIS EVENING. SURFACE HIGH PRESSURE WILL BE BUILDING
INTO WESTERN KANSAS THROUGH THIS MORNING. WE SHOULD SEE A PERIOD
OF WINDS GUSTING TO AROUND 20 KNOTS OR SO DEVELOPING AFTER
SUNRISE. WINDS WILL DIMINISH AND SWITCH TO THE EAST/NORTHEAST THIS
AFTERNOON AS THE HIGH PRESSURE MOVES OFF TO THE EAST.
WIDELY SCATTERED THUNDERSTORMS WILL LIKELY DEVELOP OFF THE FRONT
RANGE OF THE ROCKIES THIS AFTERNOON AS SOME LIMITED INSTABILITY
DEVELOPS WITH CAPE VALUES AROUND 500 J/KG OR SO. MODEL SOUNDINGS
ACROSS FAR SOUTHWEST KANSAS ARE MORE STABLE SO EXPECT THAT ANY
THUNDERSTORMS THAT DEVELOP WILL PROBABLY STAY IN EASTERN COLORADO
BEFORE DIMINISHING WITH SUNSET.
SKIES SHOULD BE MOSTLY CLEAR TONIGHT AS UPPER LEVEL RIDGING CONTINUES
TO DEVELOP. LOW TEMPERATURES MAY FALL INTO THE UPPER 40S AROUND HAYS
AND LARNED CLOSER TO THE SURFACE HIGH PRESSURE. FARTHER WEST...LOWS
SHOULD STAY IN THE MID 50S AROUND ELKHART WHERE WINDS WILL STAY UP
A LITTLE MORE TONIGHT.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 306 PM CDT SUN MAY 20 2012
MONDAY NIGHT THROUGH WEDNESDAY:
MID-UPPER TROPOSPHERIC RIDGING WILL MOVE QUICKLY EAST FROM THE
ROCKIES MONDAY NIGHT TO THE EASTERN CONUS BY WEDNESDAY. IN ITS
WAKE...A STRONG PACIFIC JET WILL NOSE INTO THE INTERMOUNTAIN
WEST/CENTRAL ROCKIES BY WEDNESDAY. WHAT THIS WILL RESULT IN IS A
CONTINUED SLOW DEEPENING OF THE LEE TROUGH ACROSS EASTERN
COLORADO...WITH LOW DEVELOPMENT ALONG THE LEE TROUGH WEDNESDAY AHEAD
OF AN APPROACHING COLD FRONT. ON MONDAY NIGHT WILL HAVE SOME 15 TO
20 POPS GOING FROM ELKHART TO SYRACUSE FOR ANY COLORADO STORMS
(PARTICULARLY OFF THE PALMER DIVIDE) WHICH MAY FORM AND DRIFT
SOUTHEAST TOWARD THE STATE BORDER. THE LATEST NAM12 DOES SUPPORT
CONVECTION APPROACHING THE STATE BORDER DURING THE MID TO LATE
EVENING HOURS BEFORE DISSIPATING DUE TO LACK OF LARGE SCALE ASCENT.
FROM 09-15Z TUESDAY...WILL HAVE TO WATCH FOR THE DEVELOPMENT OF SOME
ELEVATED CONVECTION ON THE NOSE OF A RETURNING MOISTURE PLUME.
THE GFS MODEL IS THE ONLY MODEL WHICH SHOWS A SOMEWHAT COHERENT
CONVECTIVE QPF SIGNAL WHEREAS THE ECMWF AND NAM ARE MORE OR LESS
DRY. A LOOK AT THE 09Z RUN OF THE SREF ALSO SUPPORTS THE DRIER
SOLUTION SO WILL KEEP POPS OUT OF THE GRIDS FOR 09-18Z TUESDAY. AN
ISOLATED THUNDERSTORM OR TWO MAY FORM NEAR THE SPRINGFIELD LOW LATE
TUESDAY AFTERNOON AS TEMPERATURES WARM TO THE LOWER-MID 90S SO WILL
INCLUDE SOME 15-20 POPS FOR MAINLY THE MORTON COUNTY AREA LATE TUES
AFTERNOON INTO THE EVENING HOURS. HAVE BUMPED UP THE WIND SPEEDS
TUESDAY (TO 22-25 KNOTS SUSTAINED DURING THE AFTERNOON) AS THE LEE
TROUGH PRESSURE GRADIENT WILL BE QUITE STRONG IN ADVANCE OF THE
ROCKIES UPPER JET STREAK. 13 TO 18 KNOTS OF SOUTH TO SOUTHWEST WIND
SHOULD LAST THROUGH MUCH OF THE NIGHT TUESDAY NIGHT KEEPING
TEMPERATURES RATHER MILD WITH LOWS IN THE LOWER TO MID 60S.
WEDNESDAY FORECAST IS DIFFICULT DEPENDING ON THE STRENGTH OF THE
FRONT. IF THE FRONT IS SLOWER PER THE 00Z RUN OF THE ECMWF...THEN
VERY HOT CONDITIONS WILL DEVELOP ACROSS SOUTHWEST KANSAS WEDNESDAY
AFTERNOON WITH WIDESPREAD 100 DEGREE HEAT. THE 12Z RUNS OF THE GFS
AND ESPECIALLY THE NAM SUPPORT A MORE AGGRESSIVE PUSH OF THE COLD
FRONT AND KEEPING TEMPERATURES QUITE A BIT COOLER. THE OFFICIAL
FORECAST WILL CONTINUE TO REFLECT LOWER 90S FOR MOST AREAS...BUT
THIS IS SUBJECT TO CHANGE IN FUTURE UPDATES.
THURSDAY THROUGH SUNDAY:
THE FIRST JET STREAK THAT APPROACHES THE ROCKIES WEDNESDAY/WEDNESDAY
NIGHT WILL EJECT NORTHEAST INTO THE NORTHERN PLAINS. THE FRONT THAT
PUSHES SOUTH DUE TO THIS JET WILL EVENTUALLY STALL OUT WEDNESDAY
NIGHT/THURSDAY SOMEWHERE OVER OR NEAR SOUTHWEST KANSAS. THE NEXT
DEEP TROUGH WILL DEVELOP OVER CALIFORNIA/GREAT BASIN REGION LATE
THURSDAY INTO FRIDAY. THE FRONT SHOULD LIFT BACK NORTH AS A WARM
FRONT...ESPECIALLY IF THE ECMWF IS BELIEVED. THE DETERMINISTIC GFS
AND ECMWF SOLUTIONS DO NOT AGREE ON THE DOWNSTREAM JET CONFIGURATION
AND THE STRENGTH OF THE UPPER HIGH TO ITS SOUTH. THE ECMWF MODEL
WOULD YIELD MUCH MORE SUMMER-LIKE WEATHER WITH HOT TEMPERATURES IN
THE MID TO UPPER 90S EACH DAY AND PRETTY MUCH NO PRECIPITATION WITH
THE FRONT WELL TO THE NORTH. THE GFS ON THE OTHER HAND HAS A MORE
ROBUST SURFACE HIGH TO THE NORTH KEEPING THE FRONT ACROSS THE
CENTRAL PLAINS AND YIELDING QUITE A BIT OF PRECIPITATION FOR WESTERN
KANSAS. THE TEMPTATION IS TO GO WITH THE ECMWF GIVEN ITS BETTER
LONG-TERM SKILL AT THESE FORECAST HOURS OVER THE GFS. AS SUCH...ALL
POPS ARE KEPT BELOW 15 PERCENT FOR NOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1256 PM CDT SUN MAY 20 2012
SURFACE HIGH PRESSURE WILL SETTLE ACROSS WESTERN KANSAS THIS AFTERNOON
AND TONIGHT, RESULTING IN DECREASING WINDS AND A CHANGE IN DIRECTION
FROM NORTHEAST TO SOUTHEAST. WINDS WILL BEGIN TO INCREASE BY
13-15Z MONDAY AS A TROUGH OF LOW PRESSURE DEVELOPS IN THE LEE OF
THE ROCKIES.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 48 82 58 92 / 0 10 10 10
GCK 49 82 58 95 / 10 10 10 10
EHA 54 82 58 95 / 10 20 20 20
LBL 53 82 59 94 / 10 20 20 10
HYS 48 81 58 91 / 0 10 10 10
P28 53 81 59 87 / 0 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GERARD
LONG TERM...UMSCHEID
AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1259 PM CDT SUN MAY 20 2012
...UPATED FOR AVIATION DISCUSSION...
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 335 AM CDT SUN MAY 20 2012
THE LATEST NAM AND RUC MODEL GUIDANCE SHOWS THE BAND OF 700 MILLIBAR
FRONTOGENETIC FORCING ACROSS FAR WESTERN KANSAS EARLY THIS MORNING.
THE MODELS MOVE THIS AREA OF FORCING EASTWARD AND WEAKEN IT
THROUGH SUNRISE. GIVEN THE GOING RADAR TRENDS, EXPECT THE
PRECIPITATION TO BE MOVING OUT OF WESTERN KANSAS AND THROUGH
CENTRAL KANSAS BY 12Z AS THE FORCING MOVES EAST AND WEAKENS.
WINDS HAVE BECOME LIGHT AND VARIABLE AS THE BOUNDARY LAYER
DECOUPLED THIS EVENING. SURFACE HIGH PRESSURE WILL BE BUILDING
INTO WESTERN KANSAS THROUGH THIS MORNING. WE SHOULD SEE A PERIOD
OF WINDS GUSTING TO AROUND 20 KNOTS OR SO DEVELOPING AFTER
SUNRISE. WINDS WILL DIMINISH AND SWITCH TO THE EAST/NORTHEAST THIS
AFTERNOON AS THE HIGH PRESSURE MOVES OFF TO THE EAST.
WIDELY SCATTERED THUNDERSTORMS WILL LIKELY DEVELOP OFF THE FRONT
RANGE OF THE ROCKIES THIS AFTERNOON AS SOME LIMITED INSTABILITY
DEVELOPS WITH CAPE VALUES AROUND 500 J/KG OR SO. MODEL SOUNDINGS
ACROSS FAR SOUTHWEST KANSAS ARE MORE STABLE SO EXPECT THAT ANY
THUNDERSTORMS THAT DEVELOP WILL PROBABLY STAY IN EASTERN COLORADO
BEFORE DIMINISHING WITH SUNSET.
SKIES SHOULD BE MOSTLY CLEAR TONIGHT AS UPPER LEVEL RIDGING CONTINUES
TO DEVELOP. LOW TEMPERATURES MAY FALL INTO THE UPPER 40S AROUND HAYS
AND LARNED CLOSER TO THE SURFACE HIGH PRESSURE. FARTHER WEST...LOWS
SHOULD STAY IN THE MID 50S AROUND ELKHART WHERE WINDS WILL STAY UP
A LITTLE MORE TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 335 AM CDT SUN MAY 20 2012
SHORT RANGE MODELS INDICATE A WEAK UPPER LEVEL RIDGE OF HIGH
PRESSURE DEVELOPING ACROSS THE ROCKIES EARLY MONDAY SETTING UP A
NORTHWESTERLY FLOW ALOFT ACROSS THE WESTERN HIGH PLAINS. MEANWHILE,
SURFACE HIGH PRESSURE WILL BE TRACKING EAST OUT OF THE NORTHERN
PLAINS INTO THE UPPER MIDWEST HELPING TO INFLUENCE A SOUTHEASTERLY
UPSLOPE FLOW ACROSS THE WESTERN HIGH PLAINS. AS A RESULT, DIURNALLY
DRIVEN ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ARE EXPECTED TO
DEVELOP JUST LEE OF THE ROCKIES MONDAY AFTERNOON AND EVENING,
POTENTIALLY DRIFTING EASTWARD INTO FAR SOUTHWESTERN KANSAS. WILL
RETAIN THE SLIGHT POPS ACROSS OUR FAR SOUTHWEST DUE TO THE EXPECTED
WEAK FLOW ALOFT COMBINED WITH THE UNCERTAINTY AS TO HOW FAR EAST
ANY DEVELOPING STORMS MAY REACH BEFORE DISSIPATING.
MEDIUM RANGE MODELS SHOW AN UPPER LEVEL TROUGH TRACKING SOUTHEAST
ACROSS THE PACIFIC NORTHWEST INTO THE ROCKY MOUNTAIN REGION TUESDAY
SETTING UP FOR ANOTHER CHANCE FOR PRECIP TO PORTIONS OF CENTRAL AND
WESTERN KANSAS. AS THE SYSTEM APPROACHES, INCREASING FIELDS OF
DIVERGENCE ALOFT WILL DEVELOP DOWNSTREAM OF THE TROUGH AXIS.
ADDITIONALLY, A PREVAILING LOW LEVEL SOUTHEASTERLY UPSLOPE FLOW
ACROSS THE WESTERN HIGH PLAINS WILL HELP WITH INCREASED FORCING AS
WELL AS ADVECT MORE MOISTURE NORTHWARD INTO THE REGION. AS A RESULT,
THE CHANCE FOR A FEW SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS
PORTIONS OF CENTRAL AND WESTERN KANSAS INTO TUESDAY. DRIER
CONDITIONS ARE EXPECTED ACROSS WESTERN KANSAS WEDNESDAY AS A
DEVELOPING SURFACE LOW LEE OF THE ROCKIES STRENGTHENS HELPING TO
DRAW DRIER AIR NORTHEASTWARD INTO SOUTHWEST KANSAS.
TEMPERATURES WILL BE SLIGHTLY WARMER GOING INTO MONDAY AS SURFACE
HIGH PRESSURE DROPS SOUTHEAST OUT OF THE NORTHERN PLAINS INTO THE
MID MISSISSIPPI RIVER VALLEY. THIS WILL HELP KEEP A SOUTHEASTERLY
LOW LEVEL FLOW IN PLACE ACROSS WESTERN KANSAS ALLOWING FOR SOME
MODEST WARM AIR ADVECTION. THE NAM, GFS, AND ECMWF SHOW H85
TEMPERATURES RANGING FROM THE MID TEENS(C) ACROSS CENTRAL KANSAS
TO NEAR 20C ALONG THE COLORADO BORDER. LOOK FOR HIGHS TO BE NEAR
TO JUST ABOVE 80F MONDAY AFTERNOON WITH A FEW UPPER 70S(F) STILL
POSSIBLE IN SOME LOCATIONS...MAINLY IN CENTRAL KANSAS. THE WARMING
TREND WILL CONTINUE INTO TUESDAY AS LEE SIDE TROUGHING STRENGTHENS
ACROSS EASTERN COLORADO. ENHANCED WARM AIR ADVECTION WITHIN A
STRONGER SOUTH TO SOUTHWESTERLY FLOW WILL RAISE H85 TEMPERATURES
UP TO NEAR 20C ACROSS CENTRAL KANSAS TO THE UPPER 20S(C) ACROSS
FAR SOUTHWEST KANSAS. EXPECT HIGHS FROM THE MID TO UPPER 80S(F) IN
CENTRAL KANSAS TUESDAY AFTERNOON TO THE LOWER TO MID 90S(F) IN
EXTREME SOUTHWEST KANSAS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1256 PM CDT SUN MAY 20 2012
SURFACE HIGH PRESSURE WILL SETTLE ACROSS WESTERN KANSAS THIS AFTERNOON
AND TONIGHT, RESULTING IN DECREASING WINDS AND A CHANGE IN DIRECTION
FROM NORTHEAST TO SOUTHEAST. WINDS WILL BEGIN TO INCREASE BY
13-15Z MONDAY AS A TROUGH OF LOW PRESSURE DEVELOPS IN THE LEE OF
THE ROCKIES.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 77 52 81 60 / 50 0 10 10
GCK 77 51 81 60 / 40 10 10 10
EHA 77 55 82 60 / 0 10 20 20
LBL 78 56 82 61 / 0 10 20 20
HYS 77 48 81 60 / 0 0 10 10
P28 78 55 80 61 / 10 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GERARD
LONG TERM...JJOHNSON
AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS JACKSON KY
111 PM EDT SUN MAY 20 2012
.UPDATE...
ISSUED AT 111 PM EDT SUN MAY 20 2012
VISIBLE SATELLITE SHOWS CU FIELD HAS BECOME MORE EXTENSIVE OVER THE
CUMBERLAND PLATEAU OF TN AND NORTHWARD INTO THE SW PART OF OUR
FORECAST AREA. A FEW RADAR RETURNS ALSO BEGINNING TO POP UP...MAINLY
W AND S OF FORECAST AREA. HAVE ADDED ISOLATED SHOWERS AND
THUNDERSTORMS IN THE FORECAST GRIDS OVER THE SOUTHWEST PART OF
FORECASTA AREA AND HAVE ALSO UPDATED THE ZFP.
UPDATE ISSUED AT 1131 AM EDT SUN MAY 20 2012
UPDATED THE NDFD FOR LATEST OBSERVATIONAL TRENDS. MADE SOME MINOR
ADJUSTMENTS TO AFTERNOON MAXIMUM TEMPERATURES IN A FEW SPOTS...WITH A
FEW SPOTS MAINLY IN THE SOUTH LOWERED SLIGHTLY...AND A FEW SPOTS
MAINLY IN THE NORTH INCREASED SLIGHTLY. THESE CHANGES WERE MINOR AND
DID NOT AFFECT THE ZFP...BUT THE ZFP WAS SENT TO UPDATE AFTERNOON
WORDING. HAVE DECIDED TO CONTINUE WITH THE ISOLATED...20 PERCENT
CHANCE OF SHOWERS AND THUNDERSTORMS IN THE HIGHER TERRAIN ALONG THE
VA BORDER...WITH THIS IDEA SUPPORTED BY THE 12Z NAM. THE RECENT RUNS
OF THE HRRR STILL SHOWING ISOLATED CONVECTION THIS AFTERNOON OVER THE
WESTERN PART OF THE FORECAST AREA...BUT NOT QUITE AS MUCH AS EARLIER
RUNS. DID NOT EXPAND THE AREA OF SLIGHT CHANCE THUNDERSTORMS
FROM THE CURRENT AREA BUT WILL CONTINUE TO MONITOR.
UPDATE ISSUED AT 942 AM EDT SUN MAY 20 2012
HAVE UPDATED NDFD FOR LATEST OBSERVATIONAL TRENDS...MAKING ONLY MINOR
MODIFICATIONS TO THE FORECAST DATABASE. SATELLITE SHOWS THE HIGH
CLOUDINESS OVER E KY THINNING. EXPECT THINNING TO CONTINUE PER
LATEST SATELLITE TRENDS...WITH THIS IDEA SUPPORTED BY 06Z NAM
GUIDANCE. MAIN QUESTION TO RESOLVE FOR THIS AFTERNOON IS WHETHER
THERE WILL BE ANY ISOLATED CONVECTION AND WHERE IT WOULD BE. FOR NOW
HAVE DECIDED TO CONTINUE WITH THE PREVIOUS FORECAST OF ISOLATED
CONVECTION FOR LETCHER...HARLAN AND BELL COUNTIES.
HOWEVER THERE ARE INDICATIONS ISOLATED CONVECTION COULD DEVELOP
FURTHER WEST...MORE ALONG THE EDGE OF WHERE THE HIGH CLOUD HAS BEEN.
VISIBLE SATELLITE SHOWING CU OVER PARTS OF E AND CENTRAL KY WEST OF A
LINE FROM CAMPTON TO MIDDLESBORO. CAN SEE THE CU THAT IS JUST WEST
OF JACKSON FROM THE NWS OFFICE. THE RECENT RUNS OF THE HRRR HAVE
POINTED TOWARDS ISOLATED CONVECTION WEST OF A LINE FROM SANDY HOOK TO
HARLAN THIS AFTERNOON. THINK THE NORTHERN EXTENT OF THIS MAY BE OVERDONE...AS
THERE WAS A SLIGHT CAP IN THE ILN SOUNDING...BUT THE NASHVILLE
SOUNDING WAS NOT CAPPED. THE SREF SUPPORTS THE IDEA OF CONVECTION
OVER OUR SW COUNTIES THIS AFTERNOON...AND THE HRRR INDICATES THE
GREATEST COVERAGE IN OUR FORECAST AREA WOULD BE OVER THE SOUTHWEST.
WILL MONITOR AS THE MORNING CONTINUES...AND MAY ADD ISOLATED
CONVECTION ALONG OUR SOUTHERN BORDER ALL THE WAY TO LAKE CUMBERLAND.
UPDATE ISSUED AT 638 AM EDT SUN MAY 20 2012
LOT MORE HIGH CLOUDS DEVELOPING UPSTREAM OVER THE PAST FEW HOURS. IF
THE HIGH CLOUDS PERSIST LIKE THEY APPEAR TO BE...WE MAY NOT DEVELOP
AS MUCH CU TODAY...AND THUS THE ISOLATED SHOWER/THUNDERSTORM CHANCES
IN THE SOUTHEAST COULD BE IN JEOPARDY. HOWEVER...STILL TIME FOR THIS
TO CHANGE...AND WON`T MAKE ANY CHANGES AT THIS TIME. ONCOMING
DAYSHIFT CAN REEVALUATE THE NEED FOR POPS IN THE SOUTHEAST.
OTHERWISE...TWEAKED MORNING TEMPERATURES AND DEWPOINTS TO BETTER
MATCH UP WITH OBSERVATIONS. THESE CHANGES WERE VERY MINOR...SO NO
NEED TO SEND OUT AN UPDATED FORECAST AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 305 AM EDT SUN MAY 20 2012
TROPICAL STORM ALBERTA CONTINUES TO SPIN OFF THE SOUTH CAROLINA COAST
THIS MORNING WITH A MID LEVEL TROUGH PUSHING ACROSS THE CENTRAL
PLAINS. BETWEEN THESE TWO SYSTEMS...A STRONG RIDGE OF HIGH PRESSURE
CONTINUES TO PRODUCE QUIET WEATHER FROM THE GREAT LAKES...SOUTHWARD
INTO THE OHIO VALLEY. THE SETUP WILL REMAIN VERY SIMILAR TO
YESTERDAY...WITH ANOTHER ROUND OF ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS DEVELOPING ACROSS THE TENNESSEE VALLEY REGION AS STRONG
INSTABILITY DEVELOPS MY MID AFTERNOON. MUCH LIKE YESTERDAY...A FEW
SHOWERS OR STORMS COULD SCRAPE THE COUNTIES IN KENTUCKY NEAR THE
VIRGINIA AND TENNESSEE BORDERS THIS AFTERNOON. THUS...WENT WITH
ISOLATED COVERAGE AS ANY SHOWERS AND STORMS WILL NOT AFFECT ANY LARGE
AREAS. THE SHOWERS AND STORMS WILL DISSIPATE BY SUNSET.
MEANWHILE...THE MID LEVEL TROUGH TO OUR WEST WILL PUSH INTO WESTERN
AND CENTRAL KENTUCKY LATE TONIGHT. SHOWERS AND PERHAPS A FEW
THUNDERSTORMS MAY ACCOMPANY THIS FEATURE...BUT ARE EXPECTED TO BE
WEAKENING AS THEY OUTRUN THE BETTER MID LEVEL SUPPORT. A FEW OF THESE
SHOWERS OR STORMS COULD SNEAK INTO OUR SOUTHWEST COUNTIES AROUND
DAYBREAK MONDAY. AS THE SHORTWAVE TROUGH PUSHES INTO THE OHIO VALLEY
ON MONDAY...THIS WILL PROVIDE BETTER MID/UPPER LEVEL SUPPORT FOR
SHOWER AND THUNDERSTORM DEVELOPMENT. IN ADDITION...INSTABILITY IS
EXPECTED TO INCREASE ACROSS THE REGION. THIS COMBINATION WILL LEAD TO
THE DEVELOPMENT OF A LINE OF SHOWERS AND STORMS AND WILL TRACK
EASTWARD ACROSS THE AREA MONDAY AFTERNOON. SHEAR IS VERY WEAK...IF
NOT NON-EXISTENT...SO NO THREAT FOR ANY SEVERE STORMS THIS TIME
AROUND. THIS LINE WILL WEAKEN AND DISSIPATE AS IT PUSHES TO OUR EAST
MONDAY NIGHT. IN THE WAKE OF THIS ACTIVITY...NOT MUCH SUPPORT FOR
ADDITIONAL DEVELOPMENT...ALTHOUGH AN ISOLATED SHOWER OR STORM IS
STILL POSSIBLE AS THE MID LEVEL THROUGH REMAINS ANCHORED ACROSS OUR
REGION. WENT WITH LIKELY POPS ON MONDAY WITH THE GOOD DYNAMICS AND
INSTABILITY AROUND...AND DROPPED POPS BACK TO MAINLY SLIGHT CHANCE
FOR MONDAY NIGHT.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 305 AM EDT SUN MAY 20 2012
THE MODELS CONTINUE TO HAVE SOME DIFFERENCES ALOFT WITH THE TROUGH
DIVING THROUGH THE OHIO VALLEY AT THE START OF THE EXTENDED. THE NAM
APPEARS TO BE THE MAIN OUTLIER HERE WITH A DEEPER AND SLOWER CLOSED
LOW SETTLING INTO OHIO THAN THE OTHER MODELS. BY CONTRAST THEY
REMAIN PROGRESSIVE INTO WEDNESDAY...THOUGH THE ECMWF DOES CLOSE OFF
A WEAKER VERSION OF ITS LOW FROM YESTERDAY OVER THE SOUTHERN
APPALACHIANS. THE GFS...IN CONTRAST...BRINGS IN RIDGING DURING THIS
TIME KEEPING JUST A WEAK HINT OF A LOW WELL EAST OF THE OTHER
MODELS. BY THURSDAY MORNING...THE ECMWF TAKES THE UPPER LOW EAST...
THOUGH IT STILL LAGS THE OTHER MODELS. THROUGH THE FIRST PART OF THE
EXTENDED...A BLEND IS PREFERRED...WITH SOME FAVORING THE
SLOWER/DEEPER ECMWF SOLUTION. LATER...THOUGH...THE MODELS ARE IN
BETTER AGREEMENT...AT LEAST LOCALLY...WITH RIDGING BUILDING OVERHEAD
IN RESPONSE TO A DEEP LOW PUSHING ASHORE ON THE WEST COAST. THIS
RIDGE SHOULD PROVIDE A PROTECTIVE DOME OVER THE OHIO VALLEY AND EAST
KENTUCKY HEADING INTO THE WEEKEND WHILE SHORTWAVES MOVE PAST WELL TO
THE NORTH.
SENSIBLE WEATHER WILL FEATURE STILL DECENT CHANCES OF SHOWERS AND
THUNDERSTORMS DURING THE DAY TUESDAY...FAVORING THE EAST...BENEATH
THE UPPER LOW AND ITS WEAK SFC REFLECTION OVER THE EASTERN OHIO
VALLEY. HAVE GONE WITH A DIURNAL PEAK IN THE MID TO LATE AFTERNOON
FOR POPS AND SKY COVER. A SMALL THREAT FOR CONVECTION WILL REMAIN IN
THE AREA ON WEDNESDAY AS WEAK HIGH PRESSURE SLOWLY BUILDS INTO THE
AREA FROM THE WEST AND THE UPPER LOW STARTS TO FILL AND MOVE OFF TO
THE EAST. THE CLOUDS AND PCPN WILL BE ENOUGH TO KEEP TEMPERATURES ON
THE COOL SIDE OF NORMAL FOR MOST PLACES TUESDAY AND WEDNESDAY BEFORE
A SIGNIFICANT WARMUP BEGINS IN EARNEST FRIDAY WITH THE ARRIVAL OF
SFC HIGH PRESSURE AND RIDGING ALOFT. THESE WILL COMBINE TO LIMIT
PCPN CHANCES THROUGH THE REMAINDER OF THE EXTENDED AND ALLOW
TEMPERATURES TO TAKE A RUN AT 90 DEGREES IN MANY EAST KENTUCKY
LOCATIONS BY SATURDAY AFTERNOON.
THE GRID LOAD CAME IN FAIRLY DECENT WITH A REASONABLE EMPHASIS ON
THE ECMWF SOLUTION. DID FINE TUNE THE POPS THROUGH WEDNESDAY FOR
MORE OF A DIURNAL FACTOR AND LESS IN THE SOUTHWEST THAN WAS LOADED.
ALSO...ADDED SOME USUAL TERRAIN BASED DETAILS TO THE LOW TEMPERATURE
GRIDS WEDNESDAY THROUGH FRIDAY NIGHT AS WE CONTINUE TO DRY OUT AND
SOUTHWEST FLOW KICKS IN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 111 PM EDT SUN MAY 20 2012
ISOLATED SHOWERS HAVE DEVELOPED ACROSS THE FAR SW PART OF FORECAST
AREA IN THE LAKE CUMBERLAND AREA AS OF 17Z...WITH MORE CONVECTION S AND
WEST OF THE FORECAST AREA. EXPECT MOST SHOWERS AND THUNDERSTORMS TO
BE REMAIN S OR SW OF SME AND LOZ...AND WILL NOT MENTION IN THE TAFS.
ANY CONVECTION WILL DISSIPATE THIS EVENING...BUT EXPECT SOME FOG TO
DEVELOP IN VALLEYS AND OPEN AREAS LATE TONIGHT. HAVE INTRODUCED MVFR
VSIBILITY WITH FOG IN THE LOZ AND SME TAFS FOR LATE TONIGHT AND EARLY
MONDAY MORNING. RIDGE TOP AIRPORTS SUCH AS JKL SHOULD REMAIN FOG
FREE. A COLD FRONT WILL BE APPROACHING THE REGION ON MONDAY...AND
THIS WILL BRING MORE ORGANIZED SHOWERS AND THUNDERSTORMS FROM MONDAY
AFTERNOON INTO MONDAY NIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...KAS
LONG TERM....GREIF
AVIATION...SBH
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
128 PM CDT SUN MAY 20 2012
.UPDATE...
UPDATED FOR THE 18Z AVIATION DISCUSSION BELOW.
.DISCUSSION...
/ISSUED 423 AM CDT SUN MAY 20 2012/
RAP H5 ANALYSIS ALONG WITH WATER VAPOR IMAGERY SHOWING NEG TILTED
AND FAIRLY STRONG SHORTWAVE MOVING INTO SRN MN THIS MORNING...THAT
IS FLANKED BY FAIRLY ROBUST RIDGING OVER THE ERN GREAT LAKES AND A
WEAK RIDGE NOW MOVING ACROSS THE ROCKIES. A STRONG UPPER JET AND
DEEP UPPER LOW CAN BE SEEN ACROSS THE NRN PAC THAT IS ON ITS WAY
TOWARD WRN CANADA. AT THE SFC...A COUPLE OF COLD FRONTS WERE
ANALYZED ACROSS THE AREA THIS MORNING. THE MAIN COLD FRONT AT 330
AM STRETCHED FROM NEAR ALBERT LEA UP TO THE ASHLAND...WI
AREA...WITH A SECONDARY COLD FRONT SPLAYED OUT ACROSS MN FROM NEAR
DULUTH TO FARGO. ALONG THE PRIMARY FRONT...THERE IS A SFC
CIRCULATION NEAR ROCHESTER. TO THE WEST OF ALL OF THIS...A
SPRAWLING AREA OF HIGH PRESSURE SITS ON OUR DOORSTEP ACROSS THE
NORTHERN PLAINS.
UPPER LOW MOVING INTO SRN MN WILL BE OVER THE U.P. OF MICH BY
TONIGHT AS IT SLOWLY DE-AMPLIFIES AS IT RUNS INTO THE ERN RIDGE.
UPPER RIDGE CURRENTLY OVER THE ROCKIES WILL SLIP ACROSS THE AREA
MON/TUE AS THE UPPER LOW CURRENTLY IN THE NRN PAC MOVES TO THE BC
COAST AS SIGNIFICANT TROUGH SETS UP OVER THE NRN ROCKIES. THIS
GENERAL TROUGH/RIDGE PATTERN WILL BASICALLY REMAIN IN PLACE INTO
THE HOLIDAY WEEKEND...THOUGH BECOME CONSIDERABLY MORE
AMPLIFIED...WITH H5 HEIGHTS IN SUBTROPICAL RIDGE OVER THE OHIO
VALLEY PEGGED TO RISE ABOVE 590 DM.
AT THE SFC...COLD FRONT LOOKS TO CLEAR THE ERN MPX CWA AROUND
18Z...WITH THE SFC LOW TRACKING FROM RST UP THROUGH EAU. HIGH
PRESSURE WILL QUICKLY MOVE ACROSS THE AREA MONDAY...WITH A STRONG
LEE SIDE LOW EXPECTED TO DEVELOP OVER WRN NODAK TUESDAY. FRONTAL
FEATURE WITH THIS LOW STILL ON TRACK TO MOVE INTO WRN MN
WED...THEN STALL OUT THU NIGHT AS IT RUNS INTO THE AMPLIFYING
RIDGE TO THE SOUTH AND EAST. THE GFS/ECMWF SHOW THIS FRONT HANGING
OUT NEAR THE MPX AREA AS A WARM/STATIONARY FRONT THROUGH THE
WEEKEND...WITH NO STRONG KICKER SYSTEM INDICATED UNTIL MEMORIAL
DAY AT THE EARLIEST.
FOR TODAY THE MAIN ISSUES REVOLVE AROUND MOVING POPS OUT OF THE
AREA...HOW MUCH IF AT ALL DO TEMPS WARM UP OUTSIDE OF WRN MN...AND
HOW STRONG WILL THE WINDS BE THIS MORNING. FOR POPS...THE RAP
SHOWS THE DEFORMATION BAND OF PRECIP FOLLOWING JUST W/NW OF THE
SFC LOW. USED A BLEND OF THE HRRR/GEM/NAM TO CRAWL PRECIP ACROSS
THE AREA...WITH MOST PRECIP OUT OF MN BY 18Z...WITH RAIN CLEARING
EAU/LADYSMITH AROUND 21Z. FOR TEMPS...CONTINUED NORTH
WINDS...COMBINED WITH RAINFALL BEHIND THE COLD FRONT HAS STEADILY
BEAT TEMPERATURES BACK INTO THE 50S ACROSS THE MN PORTION OF THE
CWA...WITH 40S NOT TOO FAR AWAY. GIVEN PREFERENCE FOR HANDLING OF
PRECIP THIS MORNING BY THE GEM/NAM...USED THESE MODELS FOR HIGHS
TODAY...WHICH ENDED UP BEING FAIRLY AGGRESSIVE ON THE COLD SIDE OF
THINGS...WITH HIGHS ONLY AROUND 60 UP THE I-35 CORRIDOR. THIS COULD
BUST IN A BIG WAY IF WE CLEAR OUT FOR A COUPLE OF HOURS THIS
AFTERNOON...BUT CLEARING DOES NOT LOOK TO GET TO THE 35 CORRIDOR
SOON ENOUGH TO ALLOW MUCH OF AN IMPROVEMENT IN TEMPS TODAY. FOR
WRN WI...HIGHS WILL BE ACHIEVED BY 18Z...WITH FALLING TEMPS
EXPECTED THROUGH THE AFTERNOON. AS FOR WINDS...HAVE SEEN SOME 40
TO 50 MPH WINDS GUSTS OVERNIGHT IN CENTRAL MN. THOUGH NOT
EXPECTING ANYTHING LIKE THAT TODAY...THE HRRR DOES SHOW A FAIRLY
TIGHT PRESSURE GRADIENT DEVELOPING ON THE WRN EDGE OF THE SFC LOW
WORKING THROUGH SE MN RIGHT NOW. THE HRRR HAS BEEN DOING PRETTY
GOOD AT PICKING UP THE STRONGER WINDS THROUGH THE NIGHT...SO
LEANED HEAVILY ON IT FOR WINDS THIS MORNING...WITH SOME 20-25 MPH
SUSTAINED NORTH WINDS ACROSS ERN MN THROUGH THE MORNING.
TONIGHT...SFC RIDGE OVER THE HIGHS PLAINS WILL MOVE
OVERHEAD...WITH CLEAR SKIES...CALM WINDS...AND A LOW STARTING
POINT WITH TEMPS THIS EVENING ALL CONSPIRING FOR A RATHER COOL
MORNING ON MONDAY...WITH 40S EXPECTED AND A FEW LOWS IN THE 30S
NOT OUT OF THE QUESTION ACROSS CENTRAL MN. MONDAY WILL BE VERY
PLEASANT...WITH ONLY REAL QUESTION BEING HOW LOW DO DEWPS GO IN
THE AFTERNOON. SOUNDINGS CERTAINLY INDICATE STRONG POTENTIAL FOR
SOME GOOD MIXING OF DRIER AIR TO THE SFC AND FAVORED DEWPS MONDAY
TOWARD THE MUCH DRIER MET.
FOR MONDAY NIGHT...STRONG WAA WILL BE COMING IN ALOFT OUT AHEAD OF
THE SYSTEM DEVELOPING OVER THE WRN DAKOTAS. 20.00 GFS GENERATES
SOME ELEVATED THUNDERSTORMS IN WRN MN MON NIGHT IN THIS WAA...BUT
QUICK LOOK AT SOUNDINGS AND RH HEIGHT PROFILES SHOWS ATMO BELOW
10K FT BEING QUITE DRY...SO KEPT THE FORECAST DRY WITH THE
EXPECTATION OF ANOTHER GOOD ROUND OF ACCUS/VIRGA BREAKING OUT. OF
COURSE WITH THAT WAA...A SIGNIFICANT WARM TONGUE AT H85 IS
FORECAST BY ALL MODELS TO COME INTO WRN MN...WITH TEMPS BETWEEN 16
AND 18C NOTED. LAST WEEK THIS RESULTED IN HIGHS IN THE 90S AND
THERE IS GUIDANCE SHOWING PLACES LIKE MADISON GETTING BACK INTO
THE 90S TUESDAY. HOWEVER...THE WARM FRONT SHOULD STAY OFF TO OUR
SW...SO NOT FEELING CONFIDENT IN 90S OCCURRING AGAIN...BUT DID BUMP
WRN MN UP INTO THE MID/UPPER 80S.
AFTER THAT...WHAT LOOKS LIKE A GOOD BET IS ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS WED AFTERNOON INTO THU AS ANOTHER COLD
FRONT MOVES IN. THERE ARE TIMING DIFFERENCES WITH THIS
FRONT...WITH THE GFS SHOWING MORE WED/WED NIGHT WHILE THE ECMWF IS
MORE WED NIGHT/THU. EITHER WAY...DOES LOOK LIKE ANOTHER GOOD SHOT
AT SOME HEALTHY RAINS AS THE FRONT STALLS OUT OVER/NEAR MN
THURSDAY. BEYOND THURSDAY...CONFIDENCE DECREASES QUITE A BIT ON
THE FORECAST AS THE GFS/ECMWF DIFFER ON WHERE TO PLACE THE
STATIONARY/WARM FRONT FRIDAY RIGHT THROUGH MEMORIAL DAY. GIVEN THE
STRENGTHENING RIDGE TO THE SOUTH AND EAST OVER NEXT WEEKEND...THE
FRONT COULD CERTAINLY BE A BREEDING GROUND FOR SEVERAL ROUNDS OF
THUNDERSTORMS AS MOISTURE RIDES UP OVER IT. IF WE EVER END UP ON
THE SOUTH END OF THE FRONT NEXT WEEKEND...RECORD TEMPS CERTAINLY
LOOK LIKE A POSSIBILITY AS H85 TEMPS ARE PROGGED TO GET UP INTO
THE MID/UPPER 20S C OVER THE CENTRAL PLAINS. THE 20.00
ECMWF/GFS...BOTH SHOW THIS FRONT WELL SOUTH OF THE AREA
FRIDAY...WITH IT SLOWLY LIFTING TO NORTH OF THE MPX AREA BY
SUNDAY.
&&
.AVIATION.../18Z TAF ISSUANCE/
IFR/MVFR CEILINGS WILL SLOWLY WALK ACROSS MN/WI THIS AFTERNOON AND
EARLY EVENING. SATELLITE TRENDS SHOW VFR CONDITIONS AND FILTERED
SUNSHINE IN WESTERN MN. THIS IS TRENDING EAST...SO MUCH OF MN WILL
BE VFR BY 00Z. A COMBINATION OF LIGHT RAIN/DRIZZLE IS
CONTRIBUTING TO THE REDUCED VIS...WHICH IS ABOUT HALF WAY ACROSS
MN. DRIER AIR IS MOVING IN BEHIND THE FRONT...BUT ITS VERY SLOW
AND AS A RESULT...WONDERING IF PATCHY FOG WON`T BE AN ISSUE EARLY
FRIDAY MORNING IN EASTERN MN AND WEST CENTRAL WI.
KMSP...PROBABLY SHOULD HAVE STARTED THE TAF OUT WITH AN HOUR OF
IFR...AND TRANSITIONED BACK TO MVFR. THE CEILINGS HAVE SHOWN SOME
VARIABILITY...WITH BASES RANGING FROM 600-1300FT OVER THE LAST FEW
HOURS. STARTED THE TAF REALLY WITH WHAT`S EXPECTED SHORTLY. THINK
THE WORST OF THE CIGS/VIS WILL BE FINISHED BY THE LATE AFTERNOON.
VFR THEREAFTER ALONG WITH DECREASING WIND.
OUTLOOK...
MON-TUE...VFR.
WED-WED...MVFR POSSIBLE WITH SHOWERS AND THUNDERSTORMS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/CLF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1244 PM CDT SUN MAY 20 2012
.AVIATION...18Z TAF. QUIET WEATHER EXPECTED FOR THIS TAF
PERIOD...AND OUTSIDE OF THE POSSIBILITY FOR AN OCCASIONAL HIGH END
MVFR CEILING FOR A COUPLE HOURS EARLY THIS AFTERNOON...VFR
CONDITIONS WILL REIGN. SURFACE HIGH PRESSURE CURRENTLY CENTERED
OVER WRN NEB...WHICH WILL KEEP WINDS GENERALLY NORTHERLY THROUGH
THE AFTERNOON...WITH DIMINISHING SPEEDS. THROUGH THE
EVENING/OVERNIGHT HOURS AND INTO TOMORROW...WINDS WILL REMAIN
FAIRLY LIGHT...AND GRADUALLY BECOME MORE EASTERLY...THEN
SOUTHEASTERLY AS THE SURFACE HIGH SLIDES OFF TO THE EAST OF THE
CWA.
&&
PREV DISCUSSION... /ISSUED 440 AM CDT SUN MAY 20 2012/
SHORT TERM...THROUGH TUESDAY NIGHT. OFFICIALLY...THE FORECAST
REMAINS DRY THROUGH THESE 72 HOURS. HOWEVER...THIS WILL NEED
WATCHED CLOSELY AS THERE ARE AT LEAST A FEW OPPORTUNITIES FOR
THUNDERSTORMS TO POTENTIALLY SNEAK INTO THE FORECAST. OF HIGHER
CONFIDENCE IS POSSIBLE ADVISORY-CRITERIA WINDS ON TUESDAY.
08Z OBJECTIVE SURFACE ANALYSIS PLACES THE CWA BETWEEN A 1010MB LOW
OVER WESTERN IA...AND A 1021MB HIGH STRETCHED NORTH-SOUTH ACROSS
THE PANHANDLE INTO EASTERN CO. AS A RESULT...BREEZES EARLY THIS
MORNING ARE LARGELY FROM THE WEST-NORTHWEST AREA WIDE...BUT
RANGING FROM VERY LIGHT IN THE FAR WESTERN COUNTIES...TO GUSTS
STILL AROUND 20 MPH IN THE EAST WHERE THE GRADIENT REMAINS
TIGHTEST. WATER VAPOR IMAGERY CLEARLY DEPICTS THE DEPARTING
SHORTWAVE RESPONSIBLE FOR YESTERDAY/S ROUND OF SEVERE WEATHER NOW
OVER NORTHEAST NEB...WITH BROAD QUASI-ZONAL FLOW ALOFT EXTENDING
BACK UPSTREAM TO THE EASTERN PACIFIC. RADAR AND 11-3.9 MICRON
SATELLITE IMAGERY CONFIRMS A STUBBORN AREA OF LINGERING LIGHT RAIN
THAT HAS FINALLY PUSHED OUT OF THE NORTHEASTERN CWA...IN ASSOCIATION
WITH THE PARENT AREA OF MID LEVEL CONVERGENCE/SATURATION ON THE
BACKSIDE OF THE EXITING SHORTWAVE. MEANWHILE...OFF TO THE SOUTH A
VERY NARROW BAND OF LIGHT RAIN/SPRINKLES IS MAKING ITS WAY ACROSS
PARTS OF CENTRAL KS...LIKELY DUE TO SOME SUBTLE MID LEVEL
FRONTOGENESIS IN THE ENTRANCE REGION OF A MID-UPPER JET STREAK
PULLING ACROSS NORTHERN KS/SOUTHEAST NEB.
FOLLOWING THE 05Z HRRR REFLECTIVITY CLOSELY...ALONG WITH LATEST
RADAR TRENDS...LOOKS LIKE ANY SPRINKLES IN NEB ZONES SHOULD
PRETTY MUCH BE GONE BY SUNRISE...SO WILL NOT CARRY A PRE-FIRST
PERIOD ZONE ISSUANCE TO COVER IT. AS FOR THE KS SPRINKLES...NOT
EXPECTING THESE TO BE AN ISSUE PAST SUNRISE EITHER...BUT WILL
CARRY A SLIGHT CHANCE SPRINKLE MENTION ACROSS THE FAR SOUTHERN CWA
THROUGH 12Z JUST IN CASE SOMETHING SNEAKS IN. OTHERWISE...A DRY
AND SEASONABLY PLEASANT DAY IS IN STORE. ALOFT...THE DEPARTING
SHORTWAVE AXIS WILL BE WELL UP INTO WESTERN WI BY 00Z...WITH
BROAD...MODESTLY AMPLIFIED RIDGING EXTENDING FROM THE WEST COAST
TO CENTRAL PLAINS IN ITS WAKE. AT THE SURFACE...A RIDGE AXIS WILL
GRADUALLY PASS ACROSS THE CWA THROUGH THE DAY...TRANSITIONING
WINDS FROM NORTHERLY THROUGH MUCH OF THE DAY TO MORE EASTERLY BY
DAY/S END. WITH THIS CENTER OF THIS HIGH TO THE NORTH OF THE AREA
THIS MORNING...THERE SHOULD BE AN INCREASE IN WIND SPEEDS MOST
AREAS AS BOUNDARY LAYER MIXING COMMENCES...WITH SUSTAINED SPEEDS
EASILY 10-15 MPH FOR SEVERAL HOURS...BEFORE SUBSIDING A BIT DURING
THE AFTERNOON. ALTHOUGH COULD SEE SOME LINGERING CLOUDS THIS
MORNING...AND MAYBE EVEN SOME DAYTIME FAIR WEATHER CUMULUS
DEVELOPMENT MAINLY IN EASTERN ZONES...THE CWA AS A WHOLE SHOULD
AVERAGE MOSTLY SUNNY TODAY. AS A RESULT...ANTICIPATE A FAIRLY
EFFICIENT WARM UP...AND KEPT HIGHS SIMILAR TO PREVIOUS
FORECAST...AND FAVORING THE WARMER MET GUIDANCE/RAW NAM SOLUTION
VERSUS COOLER MAV/GFS. THUS HAVE THE MAJORITY OF THE CWA REACHING
THE 72-76 RANGE.
TONIGHT...THE BROAD WESTERN TO CENTRAL CONUS RIDGE AMPLIFIES A
BIT...WITH MODEST MID LEVEL HEIGHT RISES OVER THE CENTRAL PLAINS
AS THE UPPER LEVEL FLOW BECOMES MORE NORTHERLY VERSUS WESTERLY
AROUND THE EASTERN PERIPHERY OF THE RIDGE. ALTHOUGH HAVE LEFT ALL
THUNDERSTORM MENTION OUT OF THE FORECAST FOR NOW...WILL HAVE TO KEEP
A CLOSE EYE ON FAR NORTHWEST ZONES AFTER MIDNIGHT AND ESPECIALLY
TOWARD SUNRISE...AS BOTH THE NAM/GFS ADVERTISE MODEST ELEVATED
THETA-E ADVECTION EVIDENT AT 700MB PUSHING EAST OUT OF WESTERN
NEB...ALONG WITH MAYBE UP TO A FEW HUNDRED J/KG MUCAPE ROOTED IN
THE 850-700MB LAYER. BOTH OF THESE MODELS KEEP CONVECTIVE QPF AT
LEAST SLIGHTLY NORTHWEST OF THE CWA OVER THE SANDHILLS...AND THE
00Z 4KM WRF-NMM SHOWS LITTLE HINT OF DEVELOPING CONVECTION...BUT
THIS WILL NEED CLOSELY WATCHED AS THIS KIND OF FORCING OFTEN LEADS
TO CLASSIC SUNRISE SURPRISE SHOWERS/WEAK STORMS. FOR LOW TEMPS
TONIGHT...WITH GENERALLY LIGHT EAST-SOUTHEAST BREEZES AND MOSTLY
CLEAR SKIES...OPTED TO LOWER LOWS 1-3 DEGREES FROM PREVIOUS
FORECAST...WITH MOST AREAS BETWEEN 44-48.
MONDAY...RIDGING WILL CONTINUE TO DOMINATE THE MID/UPPER
LEVELS...WITH THE AXIS GENERALLY ALIGNED ALONG THE ROCKIES...AND
CONTINUED NORTH-NORTHWEST FLOW ALOFT OVER THE CENTRAL PLAINS. AS
THE SURFACE RIDGE AXIS DEPARTS FARTHER EAST AND MODEST PRESSURE
FALLS OCCUR OVER THE HIGH PLAINS...SOUTHERLY WINDS WILL BECOME
ESTABLISHED...AND UPPED SUSTAINED SPEEDS SLIGHTLY WITH MOST OF THE
CWA SOLIDLY INTO THE 15-20 MPH RANGE MUCH OF THE DAY. DESPITE
MODEST LOW LEVEL MOISTURE RETURN WITH SURFACE DEWPOINTS POSSIBLY
APPROACHING 50 ACROSS THE WESTERN CWA...THE PRIMARY LOW LEVEL
INSTABILITY AXIS SHOULD SET UP AT LEAST 1-2 COUNTIES WEST OF THE
CWA DURING THE AFTERNOON...WITH THE NAM KEEPING ANY LATE AFTERNOON
CONVECTION SAFELY NORTHWEST OF THE AREA ACROSS THE SANDHILLS.
ASSUMING THAT NO SHOWERS/WEAK STORMS DO IN FACT DEVELOP EARLY IN
THE MORNING AS DISCUSSED ABOVE...HAVE FAIRLY HIGH CONFIDENCE IN
LEAVING STORMS OUT THROUGH THE AFTERNOON HOURS...DESPITE SPC
ASSIGNING A GENERAL THUNDER AREA TO MUCH OF THE WESTERN CWA ON THE
DAY2 OUTLOOK. WITH SOUTHERLY FLOW AND AFTERNOON MIXING TO AROUND
800MB PER NAM SOUNDINGS...KEPT HIGH TEMPS SIMILAR TO PREVIOUS
FORECAST...AND GENERALLY 2-4 DEGREES ABOVE MET/MAV GUIDANCE
CONSENSUS...WITH MOST AREAS 79-82.
MONDAY NIGHT...THE MID/UPPER RIDGE AXIS BECOMES MORE POSITIVELY
TILTED AND EXTENDS DIRECTLY THROUGH THE CENTRAL PLAINS...AS THE
RIDGE STARTS ITS EASTWARD PUSH IN RESPONSE TO AN INCOMING
SHORTWAVE AND ASSOCIATED UPPER JET STREAK MOVING INTO THE PACIFIC
NORTHWEST. ASSUMING THAT NO SANDHILLS CONVECTION SNEAKS INTO THE
CWA DURING THE EVENING...WILL STAY THE COURSE WITH A STORM-FREE
FORECAST THROUGH THE NIGHT...ALTHOUGH THIS WILL ALSO BEAR WATCHING
AS BOTH THE NAM/GFS ADVERTISE A BATCH OF ELEVATED INSTABILITY ON
THE ORDER OF 500-1000 J/KG SLIDING EAST OVER THE CWA DURING THE
NIGHT. THINKING AT THIS POINT IS THAT THESE PARCELS SHOULD REMAIN
CAPPED IN THE PRESENCE OF VERY LITTLE UPPER FORCING...WITH BETTER
CONVERGENCE ALONG THE NOSE OF THE LOW LEVEL JET AIMED MORE INTO
THE OAX CWA TOWARD THE MO RIVER...WHERE THE NAM ACTUALLY DOES
DEVELOP SOME CONVECTIVE QPF. CERTAINLY CANNOT COMPLETELY RULE OUT
A FEW SHOWERS/STORMS FLARING UP AND LATER SHIFTS MAY HAVE TO
CONSIDER ADDING A SLIGHT POP SOMEWHERE.
TUESDAY...INSTABILITY INCREASES FURTHER...AS SURFACE DEWPOINTS
CLIMB BACK INTO THE LOW-MID 50S...BUT WITH INCOMING NORTHWEST
CONUS SHORTWAVE REMAINING TO THE WEST...THIS SHOULD BE NOTHING
MORE THAN A WARM AND RATHER WINDY DAY...WITH NEAR-SURFACE PARCELS
CAPPED OFF AS SUGGESTED BY 700MB TEMPS INTO THE 11-13C RANGE. ANY
LATE AFTERNOON STORMS THAT MIGHT MANAGE TO DEVELOP IN THE REGION
SHOULD FOCUS WEST OF THE CWA NEARER THE PRIMARY SYNOPTIC DRYLINE.
AS A RESULT...EXPECT THE BIG STORY TUESDAY TO BE STRONG SOUTHERLY
WINDS...AS BOTH THE NAM/GFS DEEPEN A 989-992MB LOW OVER THE HIGH
PLAINS OVER THE COURSE OF THE DAY. THE RESULTANT STRENGTHENING
PRESSURE GRADIENT...ALONG WITH MIXING TO AT LEAST 750MB MOST
AREAS...SHOULD REALLY GET SOUTHERLY WINDS GOING. PREVIOUS FORECAST
ALREADY HAD PARTS OF THE AREA REACHING ADVISORY CRITERIA OF
SUSTAINED 30 MPH...AND GENERALLY KEPT THIS THEME INTACT...WITH THE
HIGHEST SPEEDS FOCUSED ACROSS THE WESTERN 1/2 OF THE CWA. WITH
THIS STILL BEING 5 PERIODS OUT...WAY TOO EARLY FOR A
HEADLINE...BUT WILL CONTINUE TO HIGHLIGHT IN THE HAZARDOUS WEATHER
OUTLOOK. EXPECTING MINIMAL CLOUD COVER...THIS SHOULD BE A CLASSIC
BIG WARM UP...DECENT DEWPOINT MIX-DOWN KIND OF DAY...AND HAVE
DEWPOINTS FALLING A BIT IN THE AFTERNOON...ESPECIALLY WEST. TEMP
WISE...NUDGED UP HIGHS 2-3 DEGREES FROM PREVIOUS FORECAST MOST
AREAS...AIMING FOR 89-92 MOST AREAS...AND EVEN MID 90S SOUTHWEST.
ALTHOUGH THIS IS SEVERAL DEGREES ABOVE MET/MAV GUIDANCE
CONSENSUS...IT IS MORE IN LINE WITH RAW NAM TEMPS...AND DAYS LIKE
THIS HAVE PROVEN SEVERAL TIMES IN THE PAST FEW WEEKS THAT WARMER
IS THE WAY TO GO.
TUESDAY NIGHT...YET AGAIN KEPT THE AREA FREE OF STORM
MENTION...DESPITE THE GFS TRYING TO SNEAK SOME ACTIVITY INTO
NORTHEAST ZONES AFTER MIDNIGHT. DESPITE INCREASING FORCING FROM
THE INCOMING SHORTWAVE...MOST OF THIS ENERGY WILL REMAIN BACK OVER
THE NORTHERN ROCKIES/NORTHERN PLAINS...AND BESIDES BOTH THE
NAM/GFS ADVERTISE A CONSIDERABLE CAPPING INVERSION WITH A 700MB
THERMAL RIDGE OF 13C+ SETTING UP OVER THE CWA DURING THE NIGHT.
NOT SURPRISINGLY...MODEL CONSENSUS IS TO FOCUS CONVECTION NORTH OF
THE CWA THROUGH THE NIGHT...NEAR AND JUST BEHIND AN INCOMING
SURFACE COLD FRONT AND IN AREA OF SLIGHTLY COOLER MID LEVEL TEMPS.
WILL HAVE TO IRON OUT SOME DETAILS REGARDING THE SPEED OF THIS
INCOMING COLD FRONT HOWEVER...AS BY 12Z WEDNESDAY THE NAM ALREADY
HAS THE FRONT INTO THE WESTERN CWA...WHILE THE ECMWF STILL HAS IT
BACK IN WESTERN NEB. IF ANY STORMS DO MANAGE TO DEVELOP INTO THE
NORTHERN CWA DURING THE NIGHT...STRONG TO SEVERE IS CERTAINLY
POSSIBLE...BUT CONFIDENCE STILL REMAINS LOW ENOUGH REGARDING
STORM DEVELOPMENT TO KEEP POPS BELOW THE 20 PERCENT SLIGHT CHANCE
THRESHOLD.
LONG TERM...TARTING 12Z WEDNESDAY. GUIDANCE FROM THE OPERATIONAL
GFS AND EC SUGGEST A MID LEVEL SHORT WAVE...PERHAPS A CLOSED LOW
PER THE GFS...WILL PUSH ACROSS THE NORTHERN PLAINS AND SOUTH
CENTRAL CANADA WEDNESDAY AND THURSDAY. AN ASSOCIATED SURFACE LOW
IS ALSO EXPECTED TO PUSH EAST ACROSS THE NORTHERN PLAINS AND SOUTH
CENTRAL CANADA THUS ALLOWING A LOW LEVEL BAROCLINIC ZONE TO PUSH
ACROSS OUR AREA DURING THE DAY WEDNESDAY. SURFACE RIDGING IS THEN
EXPECTED TO INFILTRATE THE CENTRAL PLAINS LATE WEDNESDAY THROUGH
EARLY FRIDAY BEFORE LOW LEVEL RETURN FLOW IS REALIZED ACROSS OUR
AREA LATE FRIDAY INTO SATURDAY.
THE OPERATIONAL GFS AND EC BOTH CONTINUE TO INDICATE CONVECTION
ALONG THE LOW LEVEL BAROCLINIC ZONE WEDNESDAY AFTERNOON AND EVENING.
THE OPERATIONAL GFS IS BECOMING SOMEWHAT MORE PROGRESSIVE AND NOW
SUGGESTS CONVECTION WILL FIRE EAST OF OUR CWA WELL AFTER THE LOW
LEVEL BAROCLINIC ZONE HAS CLEARED OUR AREA. THE EC ON THE OTHER HAND
SUGGESTS A SLIGHTLY SLOWER FROPA WITH CONVECTION POSSIBLE ALONG THE
EASTERN HALF OF OUR CWA LATE WEDNESDAY AFTERNOON INTO WEDNESDAY
EVENING. WITH 0-1KM MLCAPE VALUES PERHAPS APPROACHING 1500J/KG AND
DEEP LAYER BULK SHEAR VALUES IN THE NEIGHBORHOOD OF 40KTS...LARGE
HAIL AND PERHAPS STRONG WINDS CANNOT BE RULED OUT SHOULD
CONVECTION BE REALIZED OVER OUR AREA ALONG THE LOW LEVEL BAROCLINIC
ZONE WEDNESDAY. OPTED TO PLAY IT SAFE SINCE THE EC CONTINUES TO
SUGGEST THIS POSSIBILITY AND KEPT CONVECTION IN THE FORECAST ACROSS
THE EASTERN HALF OF THE CWA...WITH A SEVERE MENTION ALSO IN THE HWO
FOR LATE WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING.
MID AND UPPER LEVEL JET ENERGY IS EXPECTED TO PUSH OVERHEAD
THE CENTRAL PLAINS LATE WEDNESDAY...WITH THE LEFT-FRONT QUAD OF A
60-70KT MID LEVEL JET STREAK EXPECTED TO SET UP SHOP OVER OUR AREA
WEDNESDAY NIGHT INTO THURSDAY MORNING. AN INDIRECT THERMAL
CIRCULATION MAY PRODUCE ENOUGH LIFT FOR PRECIPITATION
PRODUCTION...ASSUMING ENOUGH LOW TO MID LEVEL MOISTURE...AND QPF
FIELDS FROM THE OPERATIONAL GFS AND EC BOTH SUGGEST PRECIPITATION
WILL BE REALIZED WEDNESDAY NIGHT/THURSDAY MORNING. WENT AHEAD WITH
POPS LATE WEDNESDAY INTO EARLY THURSDAY AS A RESULT. THE RIGHT-REAR
QUADRANT OF THE SAME MID LEVEL JET STREAK IS THEN EXPECTED TO PUSH
OVER NORTHERN PORTIONS OF THE CWA THURSDAY NIGHT INTO FRIDAY
MORNING...THUS BRINGING ANOTHER CHANCE FOR PRECIPITATION TO NORTHERN
PORTIONS OF OUR AREA. THE INTRODUCTION OF A ~40KT LOW LEVEL JET
STREAK WILL THEN BRING FURTHER CHANCES OF PRECIPITATION TO THE AREA
FRIDAY NIGHT INTO EARLY SATURDAY. BEYOND WEDNESDAY EVENING...LOW
LEVEL MOISTURE IS NOT OVERLY IMPRESSIVE AS SURFACE RIDGING REMAINS
ENTRENCHED ACROSS THE AREA AND AS A RESULT...INSTABILITY SUFFERS
GREATLY. LOW LEVEL MOISTURE FINALLY IMPROVES BY LATE FRIDAY AS LOW
LEVEL RETURN FLOW IS REALIZED ACROSS THE AREA...WITH DEEP LAYER
MUCAPE VALUES PERHAPS CLIMBING TO AROUND 1000J/KG BY FRIDAY NIGHT.
GIVEN ALL THIS...AM NOT INCLINED TO GO WITH ANY SEVERE WORDING IN
THE HWO BEYOND WEDNESDAY EVENING.
A SUBTLE COOLING TREND SHOULD BE NOTED ACROSS THE AREA WEDNESDAY AND
THURSDAY AS SURFACE RIDGING REMAINS OVER THE AREA. LOW LEVEL RETURN
FLOW AND RESULTANT LOW LEVEL WARM AIR ADVECTION WILL THEN PROMOTE A
WARMING TREND TO FINISH OUT THE EXTENDED FORECAST PERIOD. DESPITE
ANY TRENDS...TEMPERATURES DURING THE EXTENDED FORECAST PERIOD WILL
REMAIN AT NEAR OR ABOVE-NORMAL LEVELS FOR THIS TIME OF YEAR.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION...ADO
SHORT...PFANNKUCH
LONG...BRYANT
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
616 PM EDT SUN MAY 20 2012
.SYNOPSIS...
HIGH PRESSURE CENTERED OVER PENNSYLVANIA AND NEW YORK WILL WEAKEN
OVER THE AREA THROUGH TONIGHT. A COLD FRONT WILL MOVE THROUGH THE
AREA TOMORROW...BUT THEN BECOME STATIONARY ALONG THE APPALACHIANS
EARLY NEXT WEEK. HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE
WEST THROUGH TUESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
FOR 630 PM UPDATE...ONLY CHANGE WAS TO RAISE LOWS A DEG OR TWO WEST
TWO-THIRDS DUE TO EXPECTED INCREASED CLOUDS AND SOUTH WINDS AHEAD OF
COLD FRONT THAT ARRIVES ON MON. DRY LOW LEVELS SHOULD KEEP RAIN WEST
OF AREA THROUGH DAYBREAK ALTHOUGH FIRST BAND OF WEAKENING SHRA/TSRA
COULD MAKE A RUN TOWARD THE WESTERN OH BORDER BY MIDNIGHT BEFORE
DISSIPATING.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
MODELS STARTING OFF MONDAY MAINLY DRY ACROSS THE FORECAST AREA.
BRING IN LOW POPS ACROSS THE FAR WEST WITH COLD FRONT EXPECTED TO
BE MOVING INTO NW OH AROUND 12Z. FROM THERE INCREASE POPS QUICKLY
IN THE MORNING AS QUICK HEATING WILL PROVIDE GOOD SFC INSTABILITY
WITH CAPE INCREASING TOWARD 1500 J/KG AND LI/S DROPPING DOWN
AROUND -5. EXPAND CHC/S OF SHOWERS AND THUNDERSTORMS EAST ACROSS
THE AREA THROUGH THE AFTERNOON. FOR NOW WENT WITH CHC POPS GIVEN
SCATTERED COVERAGE OF ACTIVITY...BUT IF A MORE DEFINED LINE OF
CONVECTION DOES DEVELOP OR ANTICIPATED BASED ON GUIDANCE TONIGHT
THEN PERHAPS POPS COULD BE RAISED TO LIKELY WITH SOME REFINED
TIMING.
THINKING THAT SHRA/TS WILL GET INTO CENTRAL AREAS FROM CLE-MFD
EARLY TO MID AFTERNOON...THEN BY AROUND 20Z-22Z ACROSS THE EAST.
NOT VERY CONFIDENT ON PRECIP SPREADING WESTWARD FROM THE EAST
COAST...BUT IT MAY PROVIDE SOME ADDITIONAL MOISTURE FOR THE FRONT
TO WORK WITH LATER TOMORROW/EARLY TOMORROW NIGHT. WITH MORE CU
AROUND TOMORROW AND PRECIP CHANCES DID GO A BIT COOLER TODAY...BUT
WILL HAVE TO WATCH EASTERN AREAS AS DEPENDING ON TIMING THEY MAY
HAVE ANOTHER MID 80S DAY.
MODELS DIFFER A BIT MONDAY NIGHT AND TUESDAY WITH THE SPEED ON
DRYING OUT THE AREA. THE FRONT LOOKS TO BE STALLING EAST OF THE
AREA...PLUS AN UPPER LOW/TROUGH SOUTH OF THE AREA MAY KEEP THE
POSSIBILITY OF SHOWERS ACROSS EASTERN AREAS THROUGH TUESDAY. HIGH
PRESSURE LOOKS LIKE IT WILL BE STRONG ENOUGH TO RIDGE INTO WESTERN
AREAS ALLOWING FOR DRY CONDITIONS ACROSS PERHAPS THE WESTERN HALF
OF THE FORECAST AREA. GIVEN MODEL DIFFERENCES CONFIDENCE A BIT
LOWER AT THIS TIME BUT FOR NOW LEANED TOWARD DRY CONDITIONS
EVERYWHERE WITH HIGH PRESSURE BY WEDNESDAY AND WEDNESDAY NIGHT.
WITH THE FRONT SOUTH AND EAST OF THE AREA TUESDAY MODEL TEMPS
SHOWING COOLER CONDITIONS WITH HIGH MAINLY AROUND 70...WITH
MODERATING TEMPS TO THE MID 70S WEDNESDAY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AN UPPER RIDGE WILL BE BUILDING INTO THE AREA STARTING THURSDAY AS
THE UPPER LOW WILL BE MOVING EAST FROM THE MIDDLE ATLANTIC STATES.
SOME QUESTION HOW QUICKLY THE LOW WILL MOVE EAST AND WHETHER SOME
SHOWERS COULD BE LINGERING OVER NORTHWEST PA THURSDAY. BASED ON THE
LOCATION OF THE UPPER LOW...WILL KEEP IT DRY.
FOR FRIDAY AND THE WEEKEND A WEAK COLD FRONT IS EXPECTED TO MOVE
ACROSS THE REGION FRIDAY...THE GFS AND 12Z ECMWF AGREE. THE
DISAGREEMENT IS WHAT WILL HAPPEN SATURDAY AND SUNDAY. THE GFS HAS
HIGH PRESSURE BUILDING IN STRONGLY FROM THE NORTH...WHILE THE ECMWF
KEEPS A FRONTAL BOUNDARY WEST TO EAST ACROSS OHIO. AT THIS TIME
LEANED TOWARD KEEPING IT DRY AND WENT CLOSE TO HPC GUIDANCE FOR THE
TEMPERATURES.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
VFR CONDITIONS CONTINUING THROUGH MONDAY MORNING. A LAKE BREEZE
DEVELOPED VERY QUICKLY TODAY AND CONTINUES TO MOVE SLOWLY SOUTH.
THE LAKE BREEZE WILL DISSIPATE AROUND DAYBREAK. THE LAKE BREEZE
WAS ENOUGH CONVERGENCE TO GENERATE A FEW CUMULUS CLOUDS OVER
NORTHEAST OHIO. OTHERWISE JUST SOME CIRRUS THIS AFTERNOON...INTO
TONIGHT. THE HRRR MODELS HAS SHOWERS ON THE IN AND OH BORDER BY
05Z...IT LOOKS LIKE THEY SHOULD DISSIPATE. THIS WILL HAVE TO BE
WATCHED.
TWO WEATHER SYSTEMS WILL BE AFFECTING THE REGION MONDAY. A COLD
FRONT WILL BE MOVING IN FROM THE WEST WITH INCREASING CLOUDS. AN
UPPER LOW WILL BE MOVING SOUTH TO NORTH OVER PENNSYLVANIA AND THIS
MAY BRING SOME CLOUDS AND POSSIBLY SHOWERS INTO NORTHWEST
PA MONDAY AFTERNOON. THE TIMING OF THE SHOWERS AND THUNDERSTORMS
OVER NORTHWEST OH IS A LITTLE TRICKY...GOING WITH MID TO LATE
AFTERNOON MONDAY.
.OUTLOOK...NON-VFR CONDITIONS WILL OCCUR WITH SCATTERED
SHOWERS/THUNDERSTORMS MONDAY AFTERNOON AND TUESDAY. EARLY
MORNING FOG/HAZE MAY ALSO OCCUR TUESDAY AND WEDNESDAY.
&&
.MARINE...
RIDGE ACROSS THE LAKE WILL WEAKEN AND MOVE EAST TONIGHT AS A WEAK
COLD FRONT MOVES TOWARD THE AREA. THE COLD FRONT WILL MOVE ACROSS
THE LAKE MONDAY THROUGH MONDAY EVENING...THEN HIGH PRESSURE WILL
BUILD BACK IN. ANOTHER WEAK COLD FRONT WILL MOVE ACROSS THE LAKE
FRIDAY. HIGH PRESSURE WILL THEN BEGIN TO BUILD IN FROM THE NORTH FOR
THE WEEKEND.
THE CONCERNS ON THE LAKE ARE SOME THUNDERSTORMS COULD DEVELOP MONDAY
AFTERNOON NEEDING A SPECIAL MARINE WARNING. BEHIND THE COLD FRONT
MONDAY NIGHT THE WINDS PICK UP AND THE WAVES COULD BE CLOSE TO SMALL
CRAFT ADVISORY CRITERIA...THIS WILL HAVE TO BE MONITORED. THE NEXT
THREAT FOR A SMALL CRAFT ADVISORY COULD BE OVER THE WEEKEND...WITH A
NORTHEAST FLOW AND HIGH PRESSURE TO THE NORTH. SOME MODEL
DIFFERENCES ON THIS FEATURE.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...ABE
NEAR TERM...ABE/ADAMS
SHORT TERM...ABE
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
340 PM EDT SUN MAY 20 2012
.SYNOPSIS...
HIGH PRESSURE CENTERED OVER PENNSYLVANIA AND NEW YORK WILL WEAKEN
OVER THE AREA THROUGH TONIGHT. A COLD FRONT WILL MOVE THROUGH THE
AREA TOMORROW...BUT THEN BECOME STATIONARY ALONG THE APPALACHIANS
EARLY NEXT WEEK. HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE
WEST THROUGH TUESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
HIGH PRESSURE CENTERED OVER NY AND PA WILL CONTINUE TO KEEP
CONDITIONS DRY ACROSS THE FORECAST AREA TONIGHT. EXPECTING SOME
CIRRUS CLOUDS TO CONTINUE ACROSS THE AREA WITH LITTLE IMPACT.
TEMPS WILL BE TRICKY WITH RADIATING CONDITIONS LIKELY ACROSS THE
COOLER SPOTS INCLUDING INTERIOR NW PA...BUT WESTERN AREAS MAY SEE
MILDER LOWS GIVEN INCREASING MOISTURE AND SOUTHERLY FLOW
DEVELOPING/OR INCREASING DURING THE OVERNIGHT. USED MAINLY MAV
TEMPS WITH SOME LOCAL ADJUSTMENTS. OVERALL WENT WITH MID TO UPPER
50S ACROSS THE EASTERN 2/3 OF THE AREA AND LOWS AROUND 60 ACROSS
THE FAR WEST.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
MODELS STARTING OFF MONDAY MAINLY DRY ACROSS THE FORECAST AREA.
BRING IN LOW POPS ACROSS THE FAR WEST WITH COLD FRONT EXPECTED TO
BE MOVING INTO NW OH AROUND 12Z. FROM THERE INCREASE POPS QUICKLY
IN THE MORNING AS QUICK HEATING WILL PROVIDE GOOD SFC INSTABILITY
WITH CAPE INCREASING TOWARD 1500 J/KG AND LI/S DROPPING DOWN
AROUND -5. EXPAND CHC/S OF SHOWERS AND THUNDERSTORMS EAST ACROSS
THE AREA THROUGH THE AFTERNOON. FOR NOW WENT WITH CHC POPS GIVEN
SCATTERED COVERAGE OF ACTIVITY...BUT IF A MORE DEFINED LINE OF
CONVECTION DOES DEVELOP OR ANTICIPATED BASED ON GUIDANCE TONIGHT
THEN PERHAPS POPS COULD BE RAISED TO LIKELY WITH SOME REFINED
TIMING.
THINKING THAT SHRA/TS WILL GET INTO CENTRAL AREAS FROM CLE-MFD
EARLY TO MID AFTERNOON...THEN BY AROUND 20Z-22Z ACROSS THE EAST.
NOT VERY CONFIDENT ON PRECIP SPREADING WESTWARD FROM THE EAST
COAST...BUT IT MAY PROVIDE SOME ADDITIONAL MOISTURE FOR THE FRONT
TO WORK WITH LATER TOMORROW/EARLY TOMORROW NIGHT. WITH MORE CU
AROUND TOMORROW AND PRECIP CHANCES DID GO A BIT COOLER TODAY...BUT
WILL HAVE TO WATCH EASTERN AREAS AS DEPENDING ON TIMING THEY MAY
HAVE ANOTHER MID 80S DAY.
MODELS DIFFER A BIT MONDAY NIGHT AND TUESDAY WITH THE SPEED ON
DRYING OUT THE AREA. THE FRONT LOOKS TO BE STALLING EAST OF THE
AREA...PLUS AN UPPER LOW/TROUGH SOUTH OF THE AREA MAY KEEP THE
POSSIBILITY OF SHOWERS ACROSS EASTERN AREAS THROUGH TUESDAY. HIGH
PRESSURE LOOKS LIKE IT WILL BE STRONG ENOUGH TO RIDGE INTO WESTERN
AREAS ALLOWING FOR DRY CONDITIONS ACROSS PERHAPS THE WESTERN HALF
OF THE FORECAST AREA. GIVEN MODEL DIFFERENCES CONFIDENCE A BIT
LOWER AT THIS TIME BUT FOR NOW LEANED TOWARD DRY CONDITIONS
EVERYWHERE WITH HIGH PRESSURE BY WEDNESDAY AND WEDNESDAY NIGHT.
WITH THE FRONT SOUTH AND EAST OF THE AREA TUESDAY MODEL TEMPS
SHOWING COOLER CONDITIONS WITH HIGH MAINLY AROUND 70...WITH
MODERATING TEMPS TO THE MID 70S WEDNESDAY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AN UPPER RIDGE WILL BE BUILDING INTO THE AREA STARTING THURSDAY AS
THE UPPER LOW WILL BE MOVING EAST FROM THE MIDDLE ATLANTIC STATES.
SOME QUESTION HOW QUICKLY THE LOW WILL MOVE EAST AND WHETHER SOME
SHOWERS COULD BE LINGERING OVER NORTHWEST PA THURSDAY. BASED ON THE
LOCATION OF THE UPPER LOW...WILL KEEP IT DRY.
FOR FRIDAY AND THE WEEKEND A WEAK COLD FRONT IS EXPECTED TO MOVE
ACROSS THE REGION FRIDAY...THE GFS AND 12Z ECMWF AGREE. THE
DISAGREEMENT IS WHAT WILL HAPPEN SATURDAY AND SUNDAY. THE GFS HAS
HIGH PRESSURE BUILDING IN STRONGLY FROM THE NORTH...WHILE THE ECMWF
KEEPS A FRONTAL BOUNDARY WEST TO EAST ACROSS OHIO. AT THIS TIME
LEANED TOWARD KEEPING IT DRY AND WENT CLOSE TO HPC GUIDANCE FOR THE
TEMPERATURES.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
VFR CONDITIONS CONTINUING THROUGH MONDAY MORNING. A LAKE BREEZE
DEVELOPED VERY QUICKLY TODAY AND CONTINUES TO MOVE SLOWLY SOUTH.
THE LAKE BREEZE WILL DISSIPATE AROUND DAYBREAK. THE LAKE BREEZE
WAS ENOUGH CONVERGENCE TO GENERATE A FEW CUMULUS CLOUDS OVER
NORTHEAST OHIO. OTHERWISE JUST SOME CIRRUS THIS AFTERNOON...INTO
TONIGHT. THE HRRR MODELS HAS SHOWERS ON THE IN AND OH BORDER BY
05Z...IT LOOKS LIKE THEY SHOULD DISSIPATE. THIS WILL HAVE TO BE WATCHED.
TWO WEATHER SYSTEMS WILL BE AFFECTING THE REGION MONDAY. A COLD
FRONT WILL BE MOVING IN FROM THE WEST WITH INCREASING CLOUDS. AN
UPPER LOW WILL BE MOVING SOUTH TO NORTH OVER PENNSYLVANIA AND THIS
MAY BRING SOME CLOUDS AND POSSIBLY SHOWERS INTO NORTHWEST
PA MONDAY AFTERNOON. THE TIMING OF THE SHOWERS AND THUNDERSTORMS
OVER NORTHWEST OH IS A LITTLE TRICKY...GOING WITH MID TO LATE
AFTERNOON MONDAY.
.OUTLOOK...NON-VFR CONDITIONS WILL OCCUR WITH SCATTERED
SHOWERS/THUNDERSTORMS MONDAY AFTERNOON AND TUESDAY. EARLY
MORNING FOG/HAZE MAY ALSO OCCUR TUESDAY AND WEDNESDAY.
&&
.MARINE...
RIDGE ACROSS THE LAKE WILL WEAKEN AND MOVE EAST TONIGHT AS A WEAK
COLD FRONT MOVES TOWARD THE AREA. THE COLD FRONT WILL MOVE ACROSS
THE LAKE MONDAY THROUGH MONDAY EVENING...THEN HIGH PRESSURE WILL
BUILD BACK IN. ANOTHER WEAK COLD FRONT WILL MOVE ACROSS THE LAKE
FRIDAY. HIGH PRESSURE WILL THEN BEGIN TO BUILD IN FROM THE NORTH FOR
THE WEEKEND.
THE CONCERNS ON THE LAKE ARE SOME THUNDERSTORMS COULD DEVELOP MONDAY
AFTERNOON NEEDING A SPECIAL MARINE WARNING. BEHIND THE COLD FRONT
MONDAY NIGHT THE WINDS PICK UP AND THE WAVES COULD BE CLOSE TO SMALL
CRAFT ADVISORY CRITERIA...THIS WILL HAVE TO BE MONITORED. THE NEXT
THREAT FOR A SMALL CRAFT ADVISORY COULD BE OVER THE WEEKEND...WITH A
NORTHEAST FLOW AND HIGH PRESSURE TO THE NORTH. SOME MODEL
DIFFERENCES ON THIS FEATURE.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...ABE
NEAR TERM...ABE
SHORT TERM...ABE
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
146 PM EDT SUN MAY 20 2012
.SYNOPSIS...
HIGH PRESSURE CENTERED OVER PENNSYLVANIA AND NEW YORK WILL MOVE
GRADUALLY EAST TO THE EAST COAST BY THIS EVENING. LOW PRESSURE WILL
MOVE EAST TO THE LOWER GREAT LAKES WITH A TRAILING COLD FRONT ON
MONDAY. A WEAK WAVE OF LOW PRESSURE WILL MOVE NORTH ALONG THE
APPALACHIAN MOUNTAINS TO CENTRAL NEW YORK BY TUESDAY AFTERNOON. A
RIDGE OF HIGH PRESSURE WILL BUILD SOUTH ACROSS THE AREA ON
WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MOSTLY SUNNY SKIES ACROSS MUCH OF THE AREA THIS AFTERNOON. SOME
THIN CIRRUS ACROSS THE WEST CONTINUES TO MOVE NORTHWARD. ADJUSTED
TEMPS ESPECIALLY WITH LAKE BREEZE KICKING IN WITH TEMPS MAXED OUT
AT ERI AND ALONG THE REMAINING LAKESHORE LOCATIONS. RADAR SHOWS
ONLY FAINT LAKE BREEZE RETURN NEAR CLE AS OF 16Z.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
COLD FRONT AND ASSOCIATED LOW PRESSURE ARRIVE ON MONDAY AND BRING
WITH IT DEEPER MOISTURE AND A CHANCE FOR SHOWERS AND THUNDERSTORMS.
DUE TO THE WARM AIR ADVECTION EXPECTED...SOME INSTABILITY WILL
DEVELOP ACROSS THE AREA TO PRODUCE THUNDERSTORMS. I STILL THINK THE
CENTRAL PORTIONS OF THE FORECAST AREA COULD ESCAPE THE SHOWERS UNTIL
LATER IN THE EVENING AS MODELS ARE CONSISTENT IN HOLDING MOISTURE
BACK IN THE CENTRAL AND EASTERN PORTIONS UNTIL EVENING. BUT...WILL
STICK WITH EARLIER FORECAST AND KEEP THE SLIGHT CHANCE GOING IN THE
FORECAST FOR NOW.
MOISTURE ASSOCIATED WITH THE TROPICAL SYSTEM OFF THE CAROLINA COAST
WILL STREAM NORTH JUST WEST OF THE APPALACHIAN MOUNTAINS BY MONDAY
EVENING. THE MOISTURE SOURCE TO THE WEST AND THE TROPICAL MOISTURE
WILL MERGE OVER THE FORECAST AREA MONDAY NIGHT AND KEEP THE THREAT
FOR SHOWERS AND THUNDERSTORMS GOING.
THE COLD FRONT AND MERGED LOW PRESSURE SYSTEMS TAKE THERE GOOD OLD
TIME GETTING OUT OF THE AREA AND WILL LEAVE A LINGERING THREAT FOR
SHOWERS AND THUNDERSTORMS INTO TUESDAY...TUESDAY NIGHT AND EXITING
FINALLY ON WEDNESDAY. HIGH PRESSURE BUILDS SOUTH ACROSS THE AREA
ENDING THE THREAT FOR PRECIPITATION BY WEDNESDAY NIGHT.
DUE TO THE WEAK COLD AIR ADVECTION EXPECTED ALONG WITH THE CLOUD
COVER AND THREAT FOR SHOWERS...WILL SLIDE TEMPERATURES DOWN A COUPLE
DEGREES FROM MONDAY NIGHT THROUGH WEDNESDAY NIGHT.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
THE GFS CONTINUES TO BRING A WEAKENING COLD FRONT OR TROUGH ACROSS
THE AREA ON FRIDAY. THERE IS SOME UNCERTAINTY WITH THE FRONT... AND
THE CONSENSUS IS TO GO WITH A LESS AGGRESSIVE FRONTAL MOVEMENT...
WITH THE FRONT STAYING JUST NORTH OF THE AREA LATE IN THE WEEK. THIS
WOULD KEEP THE AREA WITHIN THE BUILDING RIDGE AND THE SOUTHWEST
FLOW. TEMPERATURES WOULD WARM WELL ABOVE NORMAL WITH HIGHS WELL INTO
THE 80S TO AROUND 90 BY THE WEEKEND.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
VFR CONDITIONS CONTINUING THROUGH MONDAY MORNING. A LAKE BREEZE
DEVELOPED VERY QUICKLY TODAY AND CONTINUES TO MOVE SLOWLY SOUTH.
THE LAKE BREEZE WILL DISSIPATE AROUND DAYBREAK. THE LAKE BREEZE
WAS ENOUGH CONVERGENCE TO GENERATE A FEW CUMULUS CLOUDS OVER
NORTHEAST OHIO. OTHERWISE JUST SOME CIRRUS THIS AFTERNOON...INTO
TONIGHT. THE HRRR MODELS HAS SHOWERS ON THE IN AND OH BORDER BY
05Z...IT LOOKS LIKE THEY SHOULD DISSIPATE. THIS WILL HAVE TO BE WATCHED.
TWO WEATHER SYSTEMS WILL BE AFFECTING THE REGION MONDAY. A COLD
FRONT WILL BE MOVING IN FROM THE WEST WITH INCREASING CLOUDS. AN
UPPER LOW WILL BE MOVING SOUTH TO NORTH OVER PENNSYLVANIA AND THIS
MAY BRING SOME CLOUDS AND POSSIBLY SHOWERS INTO NORTHWEST
PA MONDAY AFTERNOON. THE TIMING OF THE SHOWERS AND THUNDERSTORMS
OVER NORTHWEST OH IS A LITTLE TRICKY...GOING WITH MID TO LATE
AFTERNOON MONDAY.
.OUTLOOK...NON-VFR CONDITIONS WILL OCCUR WITH SCATTERED
SHOWERS/THUNDERSTORMS MONDAY AFTERNOON AND TUESDAY. EARLY
MORNING FOG/HAZE MAY ALSO OCCUR TUESDAY AND WEDNESDAY.
&&
.MARINE...
QUIET AGAIN TODAY ON LAKE ERIE WITH HIGH PRESSURE CENTERED OVER
EASTERN LAKE ERIE. WINDS WILL ESSENTIALLY BE LIGHT AND VARIABLE WITH
ONSHORE WINDS DOMINATING BY AFTERNOON.
AS THE HIGH MOVES OFF TO THE EAST THE WIND WILL COME AROUND FROM THE
SOUTH TONIGHT AND CONTINUE FROM THE SOUTH AHEAD OF A COLD FRONT ON
MONDAY. STILL SOME QUESTION AS TO THE TIMING OF THE FRONT. WINDS
COULD BECOME ONSHORE MONDAY AFTERNOON OR VARIABLE AS THE PRESSURE
GRADIENT BECOME LIGHT AND SURFACE PRESSURES FALL.
A NORTH FLOW WILL DEVELOP AFTER THE FRONT MONDAY NIGHT INTO
TUESDAY...THEN THE FLOW WILL VEER MORE FROM THE NORTHEAST AS THE
SURFACE HIGH BUILDS IN DURING THE MIDWEEK. THE GRADIENT APPEARS
LIGHT ENOUGH THAT WIND SPEEDS AND WAVES SHOULD STAY BELOW SMALL
CRAFT ADVISORY CRITERIA.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...ABE
SHORT TERM...LOMBARDY
LONG TERM...KOSARIK
AVIATION...KIELTYKA
MARINE...KOSARIK
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
557 PM CDT SUN MAY 20 2012
.UPDATE...STORMS OVER FAR NE WI STILL FLIRTING WITH SVR CRITERIA
AT TIMES. SITN OVER E-C WI STILL MARGINAL AT BEST. FRONTAL
BOUNDARY SHOWING UP AS FINE-LINE ON RADAR. THE SVR RISK IS OVER
FOR AREAS BEHIND THE FINE-LINE. STILL A LITTLE NERVOUS ABOUT AREAS
TO THE E...AND IT/S NOT OUT OF THE QUESTION YET THAT SOMETHING
COULD DEVELOP FARTHER E WHEN FINE-LINE STARTS TO INTERACT WITH THE LAKE
BREEZE. ADMITTEDLY...THE CHCS OF THIS KICKING OFF A SVR STORM ARE
RATHER LOW. BUT HARD TO CANCEL WATCH WITH THIS MESO-SCALE
BOUNDARY INTERACTING STILL LURKING OUT THERE. PLAN TO JUST KEEP
NIPPING AWAY AT THE WESTERN EDGE OF THE WATCH FOR NOW.
SKOWRONSKI
&&
.PREV DISCUSSION...ISSUED AT 456 PM CDT SUN MAY 20 2012...
UPDATE...SVR THREAT CONTINUES OVER NERN WI. STORMS OVER NE WI ARE
IN THE AREA OF STRONGEST MOISTURE CONVERGENCE...AND ARE LIKELY TO
POSE A RISK OF SVR UNTIL THEY EXIT THE AREA. LOCAL MESO PLOTS
SUGGEST SOME INHIBITION STILL EXISTS FM DOOR CO NWD...SO WL SEE
HOW STORMS BEHAVE AS THEY NEAR THE LAKE.
SITN OVER E-C WI LESS CLEAR CUT. STILL SOME INSTABILITY AND INCRG
MOISTURE CONVERGENCE. BUT NOT MUCH HAS HAPPENED IN THIS AREA YET.
QG FORCING SWINGING THROUGH THE AREA AND INCREASED LOW-LEVEL
CONVERGENCE SUPPORT HOLDING ONTO THE WATCH FOR A WHILE LONGER
DESPITE LIMITED DEVELOPMENT THUS FAR. SVR THREAT MAY NOT BE AS
GREAT AS IT APPEARED EARLIER...BUT NOT COMFORTABLE CANCELING THE
WATCH UNTIL FRONT GOES THROUGH AND WINDS SHIFT W.
SKOWRONSKI
DISCUSSION ISSUED AT 419 PM CDT SUN MAY 20 2012...
UPDATE...SVR THREAT ENDING BEHIND ONGOING STORMS. WL BE CLEARING
THE SWRN/FAR WRN PART OF THE FCST AREA.
ALSO ADDED SC.Y TO THE NEARSHORE WATERS. WINDS MAY NOT BE QUITE AS
GUSTY OVER THE LAKE RIGHT NOW DUE TO STABILITY CONCERNS AND SLY
FLOW UP THE LENGTH OF THE LAKE...BUT SHOULD BE QUITE STG ON THE
BAY. SHOULD SEE A BRIEF PERIOD OF G30-35 KTS WINDS RIGHT BEHIND
THE COLD FRONT...AND WLY FLOW THEN SHOULD DRIVE STRONGER GUSTS OUT
OVER THE NSH WATERS.
SKOWRONSKI
DISCUSSION ISSUED AT 238 PM CDT SUN MAY 20 2012...
SHORT TERM...TONIGHT AND MONDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE
MOVING NORTHEAST OVER CENTRAL WISCONSIN EARLY THIS AFTERNOON...JUST
AHEAD OF A SHORTWAVE TROUGH OVER EASTERN MINNESOTA. LINES OF
CONVECTION DEVELOPED AHEAD OF THIS SHORTWAVE TROUGH OVER
NORTH-CENTRAL AND NORTHWEST WISCONSIN BY MIDDAY WHERE WIND DAMAGE
AND HALF INCH HAIL OCCURRED EARLIER. INTENSIFICATION OF THE STORMS
REMAINS POSSIBLE THROUGH THE AFTERNOON...AS THE STORMS ENCOUNTER THE
INSTABILITY AXIS FROM WAUSHARA TO LAND O LAKES WHERE ML CAPES RANGE
FROM 1000-1500 J/KG. CAPES MAY NOT GET AS HIGH AS PREVIOUSLY
THOUGHT...SINCE SOME DRIER AIR IS MIXING DOWN TO THE SURFACE. DEEP
LAYER SHEAR REMAINS ABOUT 30-35 KTS...THOUGH THE VAD IS PICKING UP
ON 40KTS AT 2KFT. DAMAGING WIND GUSTS AND LARGE HAIL WILL REMAIN
THE PRIMARY THREATS WITH THE STORMS UNTIL THE SURFACE LOW AND COLD
FRONT DEPART EARLY THIS EVENING.
TONIGHT...LOW PRESSURE WILL MOVE NORTHEAST TONIGHT FROM FAR
NORTHEAST WISCONSIN TO EASTERN LAKE SUPERIOR. THE FRONT WILL STILL
HAVE TO CLEAR DOOR COUNTY AND WILL LEAVE LIKELY POPS FOR THE FIRST
PART OF THE EVENING. BEHIND THE FRONT...THINK WILL SEE SCATTERED
SHOWERS AND ISOLD THUNDERSTORMS EARLY THIS EVENING...THEN LIGHT
SHOWERS THROUGH MIDNIGHT AS COLDER AIR ARRIVES BEHIND THE
FRONT...AND A WIDESPREAD LOW STRATUS DECK SPREADS ACROSS THE AREA.
NORTHERN WISCONSIN MAY SEE THE LIGHT SHOWER ACTIVITY CONTINUE INTO
THE EARLY OVERNIGHT HOURS AS SOUNDINGS STILL LOOK SATURATED UP TO
ABOUT 700MB AT 06Z...BUT WILL GO DRY TO LINE UP WITH SURROUNDING
OFFICES. AT LEAST PARTIAL CLEARING WILL ARRIVE INTO NORTH-CENTRAL
WISCONSIN LATE TONIGHT WHEN DRIER AIR MOVES INTO THAT REGION. LOW
TEMPS RANGING FROM THE LOW 40S NORTH TO LOW 50S SE.
MONDAY...LOW STRATUS WILL PROBABLY HANG ON OVER EASTERN WISCONSIN TO
START THE DAY BUT SHOULD QUICKLY MOVE TO THE EAST DUE TO THE ARRIVAL
OF A MUCH DRIER AIRMASS AND REBOUNDING LOW LEVEL TEMPS. AS SKIES
TURN MOSTLY CLEAR TO PARTLY CLOUDY EVERYWHERE BY LATE IN THE
MORNING...HIGHS WILL REACH FROM THE MIDDLE 60S NORTH TO LOW 70S
SOUTH.
LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY. A COOL SURFACE HIGH
PRESSURE SYSTEM WITH UPPER RIDGE WILL SETTLE INTO THE AREA FOR THE
FIRST HALF OF THE WORK WEEK WITH QUIET WEATHER AND COMFORTABLE
TEMPERATURES. THE PREVIOUS FORECAST RUN LOWERED TEMPS FOR MONDAY
NIGHT TO WARRANT NON HEADLINE FROST WORDING FOR NORTHERN
WISCONSIN. LATEST RUNS INDICATE LIGHT RETURN FLOW PCPN ALREADY
NEAR THE MN/WI BORDER AT 12Z TUESDAY. CLOUDS MAY ADVANCE INTO
NROTHERN WISCONSIN OVERNIGHT IN THE WESTERLY FLOW TO LIMIT TEMPS
FALLING. THIS TREND SUGGESTS LESS OF A TREND TOWARD ANY FROST
ADVISORY AT THIS TIME SO WILL CONTINUE WITH THE GOING FORECAST.
MAIN FORECAST CHALLENGE ARRIVES LATER IN THE NEW WORK WEEK AS A
BROAD UPPER TROUGH WORKS INTO THE WESTERN STATES AND NORTHERN
PLAINS. MEDIUM RANGE MODELS RUNS IN BETTER AGREEMENT WITH
CONFINING BEST POTENTIAL OF CONVECTION WITH THE RETURN FLOW OVER
THE NORTHERN PLAINS WITH PERHAPS BRUSHING NORTHWEST THIRD OF THE
STATE WEDNESDAY THROUGH WEDNESDAY NIGHT. SHORT WAVE TROUGH WITH
FRONTAL SYSTEM IS PROGGED TO SLIDE OVER STATE SOMETIME FROM
THURSDAY INTO THURSDAY NIGHT TO WARRANT THE HIGHEST PCPN CHC
DURING THIS PERIOD.
FRIDAY INTO SUNDAY...THE REGION WILL BE ON THE NORTHERN PERIPHERY
OF BROAD UPPER RIDGE OVER THE SOUTHERN PLAINS INTO THE SOUTHEAST
STATES. HOWEVER MODELS DIVERT ON CRITICAL LOCATION OF SURFACE
BOUNDARY SEPARATING DEEPER MOISTURE TO THE SOUTH FROM CONTINUED
DRIER CANADA AIR. 00Z ECMWF MAINLY POSITIONS THIS BOUNDARY ALONG
THE WISCONSIN ILLINOIS BORDER WHILE THE GFS IS FURTHER SOUTH. THE
12Z GFS KEEPS THE PCPN SOUTH...WHILE DEVELOPING CONVECTION THIS
SUNDAY AFTERNOON WILL LIKELY PREVENT A CHANCE TO LOOK AT THE
LATEST ECMWF RUN.
&&
.AVIATION...LOW PRESSURE WILL TRACK OVER CENTRAL AND NORTHEAST
WISCONSIN THIS AFTERNOON AND INTO EARLY THIS EVENING. AHEAD OF THE
LOW AND ALONG ITS COLD FRONT...NUMEROUS SHOWERS AND THUNDERSTORMS
WILL DEVELOP EARLY THIS AFTERNOON AND MOVE EAST ACROSS THE AREA
BEFORE EXITING EARLY THIS EVENING. SOME STORMS MAY BECOME SEVERE
WITH DAMAGING WINDS AND LARGE HAIL AS THE PRIMARY THREATS. BEHIND
THE LOW AND FRONT...A WIDESPREAD AREA OF IFR/MVFR STRATUS WILL MOVE
ACROSS THE AREA THROUGH LATE TONIGHT. SCATTERED SHOWERS OR DRIZZLE
WILL BE POSSIBLE OUT OF THIS STRATUS DECK...MAINLY OVER N-C
WISCONSIN. SKY CONDITIONS IMPROVE TOMORROW MORNING TO VFR.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
456 PM CDT SUN MAY 20 2012
.UPDATE...SVR THREAT CONTINUES OVER NERN WI. STORMS OVER NE WI ARE
IN THE AREA OF STRONGEST MOISTURE CONVERGENCE...AND ARE LIKELY TO
POSE A RISK OF SVR UNTIL THEY EXIT THE AREA. LOCAL MESO PLOTS
SUGGEST SOME INHIBITION STILL EXISTS FM DOOR CO NWD...SO WL SEE
HOW STORMS BEHAVE AS THEY NEAR THE LAKE.
SITN OVER E-C WI LESS CLEAR CUT. STILL SOME INSTABILITY AND INCRG
MOISTURE CONVERGENCE. BUT NOT MUCH HAS HAPPENED IN THIS AREA YET.
QG FORCING SWINGING THROUGH THE AREA AND INCREASED LOW-LEVEL
CONVERGENCE SUPPORT HOLDING ONTO THE WATCH FOR A WHILE LONGER
DESPITE LIMITED DEVELOPMENT THUS FAR. SVR THREAT MAY NOT BE AS
GREAT AS IT APPEARED EARLIER...BUT NOT COMFORTABLE CANCELING THE
WATCH UNTIL FRONT GOES THROUGH AND WINDS SHIFT W.
SKOWRONSKI
&&
.PREV DISCUSSION...ISSUED AT 419 PM CDT SUN MAY 20 2012...
UPDATE...SVR THREAT ENDING BEHIND ONGOING STORMS. WL BE CLEARING
THE SWRN/FAR WRN PART OF THE FCST AREA.
ALSO ADDED SC.Y TO THE NEARSHORE WATERS. WINDS MAY NOT BE QUITE AS
GUSTY OVER THE LAKE RIGHT NOW DUE TO STABILITY CONCERNS AND SLY
FLOW UP THE LENGTH OF THE LAKE...BUT SHOULD BE QUITE STG ON THE
BAY. SHOULD SEE A BRIEF PERIOD OF G30-35 KTS WINDS RIGHT BEHIND
THE COLD FRONT...AND WLY FLOW THEN SHOULD DRIVE STRONGER GUSTS OUT
OVER THE NSH WATERS.
SKOWRONSKI
DISCUSSION ISSUED AT 238 PM CDT SUN MAY 20 2012...
SHORT TERM...TONIGHT AND MONDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE
MOVING NORTHEAST OVER CENTRAL WISCONSIN EARLY THIS AFTERNOON...JUST
AHEAD OF A SHORTWAVE TROUGH OVER EASTERN MINNESOTA. LINES OF
CONVECTION DEVELOPED AHEAD OF THIS SHORTWAVE TROUGH OVER
NORTH-CENTRAL AND NORTHWEST WISCONSIN BY MIDDAY WHERE WIND DAMAGE
AND HALF INCH HAIL OCCURRED EARLIER. INTENSIFICATION OF THE STORMS
REMAINS POSSIBLE THROUGH THE AFTERNOON...AS THE STORMS ENCOUNTER THE
INSTABILITY AXIS FROM WAUSHARA TO LAND O LAKES WHERE ML CAPES RANGE
FROM 1000-1500 J/KG. CAPES MAY NOT GET AS HIGH AS PREVIOUSLY
THOUGHT...SINCE SOME DRIER AIR IS MIXING DOWN TO THE SURFACE. DEEP
LAYER SHEAR REMAINS ABOUT 30-35 KTS...THOUGH THE VAD IS PICKING UP
ON 40KTS AT 2KFT. DAMAGING WIND GUSTS AND LARGE HAIL WILL REMAIN
THE PRIMARY THREATS WITH THE STORMS UNTIL THE SURFACE LOW AND COLD
FRONT DEPART EARLY THIS EVENING.
TONIGHT...LOW PRESSURE WILL MOVE NORTHEAST TONIGHT FROM FAR
NORTHEAST WISCONSIN TO EASTERN LAKE SUPERIOR. THE FRONT WILL STILL
HAVE TO CLEAR DOOR COUNTY AND WILL LEAVE LIKELY POPS FOR THE FIRST
PART OF THE EVENING. BEHIND THE FRONT...THINK WILL SEE SCATTERED
SHOWERS AND ISOLD THUNDERSTORMS EARLY THIS EVENING...THEN LIGHT
SHOWERS THROUGH MIDNIGHT AS COLDER AIR ARRIVES BEHIND THE
FRONT...AND A WIDESPREAD LOW STRATUS DECK SPREADS ACROSS THE AREA.
NORTHERN WISCONSIN MAY SEE THE LIGHT SHOWER ACTIVITY CONTINUE INTO
THE EARLY OVERNIGHT HOURS AS SOUNDINGS STILL LOOK SATURATED UP TO
ABOUT 700MB AT 06Z...BUT WILL GO DRY TO LINE UP WITH SURROUNDING
OFFICES. AT LEAST PARTIAL CLEARING WILL ARRIVE INTO NORTH-CENTRAL
WISCONSIN LATE TONIGHT WHEN DRIER AIR MOVES INTO THAT REGION. LOW
TEMPS RANGING FROM THE LOW 40S NORTH TO LOW 50S SE.
MONDAY...LOW STRATUS WILL PROBABLY HANG ON OVER EASTERN WISCONSIN TO
START THE DAY BUT SHOULD QUICKLY MOVE TO THE EAST DUE TO THE ARRIVAL
OF A MUCH DRIER AIRMASS AND REBOUNDING LOW LEVEL TEMPS. AS SKIES
TURN MOSTLY CLEAR TO PARTLY CLOUDY EVERYWHERE BY LATE IN THE
MORNING...HIGHS WILL REACH FROM THE MIDDLE 60S NORTH TO LOW 70S
SOUTH.
LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY. A COOL SURFACE HIGH
PRESSURE SYSTEM WITH UPPER RIDGE WILL SETTLE INTO THE AREA FOR THE
FIRST HALF OF THE WORK WEEK WITH QUIET WEATHER AND COMFORTABLE
TEMPERATURES. THE PREVIOUS FORECAST RUN LOWERED TEMPS FOR MONDAY
NIGHT TO WARRANT NON HEADLINE FROST WORDING FOR NORTHERN
WISCONSIN. LATEST RUNS INDICATE LIGHT RETURN FLOW PCPN ALREADY
NEAR THE MN/WI BORDER AT 12Z TUESDAY. CLOUDS MAY ADVANCE INTO
NROTHERN WISCONSIN OVERNIGHT IN THE WESTERLY FLOW TO LIMIT TEMPS
FALLING. THIS TREND SUGGESTS LESS OF A TREND TOWARD ANY FROST
ADVISORY AT THIS TIME SO WILL CONTINUE WITH THE GOING FORECAST.
MAIN FORECAST CHALLENGE ARRIVES LATER IN THE NEW WORK WEEK AS A
BROAD UPPER TROUGH WORKS INTO THE WESTERN STATES AND NORTHERN
PLAINS. MEDIUM RANGE MODELS RUNS IN BETTER AGREEMENT WITH
CONFINING BEST POTENTIAL OF CONVECTION WITH THE RETURN FLOW OVER
THE NORTHERN PLAINS WITH PERHAPS BRUSHING NORTHWEST THIRD OF THE
STATE WEDNESDAY THROUGH WEDNESDAY NIGHT. SHORT WAVE TROUGH WITH
FRONTAL SYSTEM IS PROGGED TO SLIDE OVER STATE SOMETIME FROM
THURSDAY INTO THURSDAY NIGHT TO WARRANT THE HIGHEST PCPN CHC
DURING THIS PERIOD.
FRIDAY INTO SUNDAY...THE REGION WILL BE ON THE NORTHERN PERIPHERY
OF BROAD UPPER RIDGE OVER THE SOUTHERN PLAINS INTO THE SOUTHEAST
STATES. HOWEVER MODELS DIVERT ON CRITICAL LOCATION OF SURFACE
BOUNDARY SEPARATING DEEPER MOISTURE TO THE SOUTH FROM CONTINUED
DRIER CANADA AIR. 00Z ECMWF MAINLY POSITIONS THIS BOUNDARY ALONG
THE WISCONSIN ILLINOIS BORDER WHILE THE GFS IS FURTHER SOUTH. THE
12Z GFS KEEPS THE PCPN SOUTH...WHILE DEVELOPING CONVECTION THIS
SUNDAY AFTERNOON WILL LIKELY PREVENT A CHANCE TO LOOK AT THE
LATEST ECMWF RUN.
&&
.AVIATION...LOW PRESSURE WILL TRACK OVER CENTRAL AND NORTHEAST
WISCONSIN THIS AFTERNOON AND INTO EARLY THIS EVENING. AHEAD OF THE
LOW AND ALONG ITS COLD FRONT...NUMEROUS SHOWERS AND THUNDERSTORMS
WILL DEVELOP EARLY THIS AFTERNOON AND MOVE EAST ACROSS THE AREA
BEFORE EXITING EARLY THIS EVENING. SOME STORMS MAY BECOME SEVERE
WITH DAMAGING WINDS AND LARGE HAIL AS THE PRIMARY THREATS. BEHIND
THE LOW AND FRONT...A WIDESPREAD AREA OF IFR/MVFR STRATUS WILL MOVE
ACROSS THE AREA THROUGH LATE TONIGHT. SCATTERED SHOWERS OR DRIZZLE
WILL BE POSSIBLE OUT OF THIS STRATUS DECK...MAINLY OVER N-C
WISCONSIN. SKY CONDITIONS IMPROVE TOMORROW MORNING TO VFR.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
419 PM CDT SUN MAY 20 2012
.UPDATE...SVR THREAT ENDING BEHIND ONGOING STORMS. WL BE CLEARING
THE SWRN/FAR WRN PART OF THE FCST AREA.
ALSO ADDED SC.Y TO THE NEARSHORE WATERS. WINDS MAY NOT BE QUITE AS
GUSTY OVER THE LAKE RIGHT NOW DUE TO STABILITY CONCERNS AND SLY
FLOW UP THE LENGTH OF THE LAKE...BUT SHOULD BE QUITE STG ON THE
BAY. SHOULD SEE A BRIEF PERIOD OF G30-35 KTS WINDS RIGHT BEHIND
THE COLD FRONT...AND WLY FLOW THEN SHOULD DRIVE STRONGER GUSTS OUT
OVER THE NSH WATERS.
SKOWRONSKI
&&
.PREV DISCUSSION...ISSUED AT 238 PM CDT SUN MAY 20 2012...
SHORT TERM...TONIGHT AND MONDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE
MOVING NORTHEAST OVER CENTRAL WISCONSIN EARLY THIS AFTERNOON...JUST
AHEAD OF A SHORTWAVE TROUGH OVER EASTERN MINNESOTA. LINES OF
CONVECTION DEVELOPED AHEAD OF THIS SHORTWAVE TROUGH OVER
NORTH-CENTRAL AND NORTHWEST WISCONSIN BY MIDDAY WHERE WIND DAMAGE
AND HALF INCH HAIL OCCURRED EARLIER. INTENSIFICATION OF THE STORMS
REMAINS POSSIBLE THROUGH THE AFTERNOON...AS THE STORMS ENCOUNTER THE
INSTABILITY AXIS FROM WAUSHARA TO LAND O LAKES WHERE ML CAPES RANGE
FROM 1000-1500 J/KG. CAPES MAY NOT GET AS HIGH AS PREVIOUSLY
THOUGHT...SINCE SOME DRIER AIR IS MIXING DOWN TO THE SURFACE. DEEP
LAYER SHEAR REMAINS ABOUT 30-35 KTS...THOUGH THE VAD IS PICKING UP
ON 40KTS AT 2KFT. DAMAGING WIND GUSTS AND LARGE HAIL WILL REMAIN
THE PRIMARY THREATS WITH THE STORMS UNTIL THE SURFACE LOW AND COLD
FRONT DEPART EARLY THIS EVENING.
TONIGHT...LOW PRESSURE WILL MOVE NORTHEAST TONIGHT FROM FAR
NORTHEAST WISCONSIN TO EASTERN LAKE SUPERIOR. THE FRONT WILL STILL
HAVE TO CLEAR DOOR COUNTY AND WILL LEAVE LIKELY POPS FOR THE FIRST
PART OF THE EVENING. BEHIND THE FRONT...THINK WILL SEE SCATTERED
SHOWERS AND ISOLD THUNDERSTORMS EARLY THIS EVENING...THEN LIGHT
SHOWERS THROUGH MIDNIGHT AS COLDER AIR ARRIVES BEHIND THE
FRONT...AND A WIDESPREAD LOW STRATUS DECK SPREADS ACROSS THE AREA.
NORTHERN WISCONSIN MAY SEE THE LIGHT SHOWER ACTIVITY CONTINUE INTO
THE EARLY OVERNIGHT HOURS AS SOUNDINGS STILL LOOK SATURATED UP TO
ABOUT 700MB AT 06Z...BUT WILL GO DRY TO LINE UP WITH SURROUNDING
OFFICES. AT LEAST PARTIAL CLEARING WILL ARRIVE INTO NORTH-CENTRAL
WISCONSIN LATE TONIGHT WHEN DRIER AIR MOVES INTO THAT REGION. LOW
TEMPS RANGING FROM THE LOW 40S NORTH TO LOW 50S SE.
MONDAY...LOW STRATUS WILL PROBABLY HANG ON OVER EASTERN WISCONSIN TO
START THE DAY BUT SHOULD QUICKLY MOVE TO THE EAST DUE TO THE ARRIVAL
OF A MUCH DRIER AIRMASS AND REBOUNDING LOW LEVEL TEMPS. AS SKIES
TURN MOSTLY CLEAR TO PARTLY CLOUDY EVERYWHERE BY LATE IN THE
MORNING...HIGHS WILL REACH FROM THE MIDDLE 60S NORTH TO LOW 70S
SOUTH.
LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY. A COOL SURFACE HIGH
PRESSURE SYSTEM WITH UPPER RIDGE WILL SETTLE INTO THE AREA FOR THE
FIRST HALF OF THE WORK WEEK WITH QUIET WEATHER AND COMFORTABLE
TEMPERATURES. THE PREVIOUS FORECAST RUN LOWERED TEMPS FOR MONDAY
NIGHT TO WARRANT NON HEADLINE FROST WORDING FOR NORTHERN
WISCONSIN. LATEST RUNS INDICATE LIGHT RETURN FLOW PCPN ALREADY
NEAR THE MN/WI BORDER AT 12Z TUESDAY. CLOUDS MAY ADVANCE INTO
NROTHERN WISCONSIN OVERNIGHT IN THE WESTERLY FLOW TO LIMIT TEMPS
FALLING. THIS TREND SUGGESTS LESS OF A TREND TOWARD ANY FROST
ADVISORY AT THIS TIME SO WILL CONTINUE WITH THE GOING FORECAST.
MAIN FORECAST CHALLENGE ARRIVES LATER IN THE NEW WORK WEEK AS A
BROAD UPPER TROUGH WORKS INTO THE WESTERN STATES AND NORTHERN
PLAINS. MEDIUM RANGE MODELS RUNS IN BETTER AGREEMENT WITH
CONFINING BEST POTENTIAL OF CONVECTION WITH THE RETURN FLOW OVER
THE NORTHERN PLAINS WITH PERHAPS BRUSHING NORTHWEST THIRD OF THE
STATE WEDNESDAY THROUGH WEDNESDAY NIGHT. SHORT WAVE TROUGH WITH
FRONTAL SYSTEM IS PROGGED TO SLIDE OVER STATE SOMETIME FROM
THURSDAY INTO THURSDAY NIGHT TO WARRANT THE HIGHEST PCPN CHC
DURING THIS PERIOD.
FRIDAY INTO SUNDAY...THE REGION WILL BE ON THE NORTHERN PERIPHERY
OF BROAD UPPER RIDGE OVER THE SOUTHERN PLAINS INTO THE SOUTHEAST
STATES. HOWEVER MODELS DIVERT ON CRITICAL LOCATION OF SURFACE
BOUNDARY SEPARATING DEEPER MOISTURE TO THE SOUTH FROM CONTINUED
DRIER CANADA AIR. 00Z ECMWF MAINLY POSITIONS THIS BOUNDARY ALONG
THE WISCONSIN ILLINOIS BORDER WHILE THE GFS IS FURTHER SOUTH. THE
12Z GFS KEEPS THE PCPN SOUTH...WHILE DEVELOPING CONVECTION THIS
SUNDAY AFTERNOON WILL LIKELY PREVENT A CHANCE TO LOOK AT THE
LATEST ECMWF RUN.
&&
.AVIATION...LOW PRESSURE WILL TRACK OVER CENTRAL AND NORTHEAST
WISCONSIN THIS AFTERNOON AND INTO EARLY THIS EVENING. AHEAD OF THE
LOW AND ALONG ITS COLD FRONT...NUMEROUS SHOWERS AND THUNDERSTORMS
WILL DEVELOP EARLY THIS AFTERNOON AND MOVE EAST ACROSS THE AREA
BEFORE EXITING EARLY THIS EVENING. SOME STORMS MAY BECOME SEVERE
WITH DAMAGING WINDS AND LARGE HAIL AS THE PRIMARY THREATS. BEHIND
THE LOW AND FRONT...A WIDESPREAD AREA OF IFR/MVFR STRATUS WILL MOVE
ACROSS THE AREA THROUGH LATE TONIGHT. SCATTERED SHOWERS OR DRIZZLE
WILL BE POSSIBLE OUT OF THIS STRATUS DECK...MAINLY OVER N-C
WISCONSIN. SKY CONDITIONS IMPROVE TOMORROW MORNING TO VFR.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
358 PM CDT SUN MAY 20 2012
...THIS AFTERNOON INTO EARLY EVENING...FORECAST CONFIDENCE MEDIUM.
SURFACE CONVERGENCE RIGHT ALONG THE PRE-FRONTAL TROUGH LOCATED NEAR
MADISON AND JANESVILLE AT 230 PM...IDENTIFIED BY A WIND SHIFT IN THE
SURFACE OBS...WILL BE THE FOCUS FOR SOME INITIAL CONVECTION PRIOR TO
THE MAIN FRONTAL BOUNDARY LOCATED IN THE FAR WESTERN FORECAST AREA
/CWA/...WHERE THERE IS ANOTHER WIND SHIFT. A FEW QUICK-MOVING POP-UP
SHOWERS WITH ISOLATED THUNDER ARE DEVELOPING JUST AHEAD OF THE
PRE-FRONTAL TROUGH EARLY THIS AFTERNOON AS WELL. THESE ARE A RESULT
AS GENERAL INSTABILITY WITH MIXED LAYER CAPE AROUND 1000 J/KG.
STEEP LOW LEVEL LAPSE RATES WITH A WELL-MIXED LAYER UP TO 7000 FEET
ARE ALLOWING FOR WINDS GUSTING UP TO 30 KNOTS. EXPECT HIGHER GUSTS
BENEATH SHOWERS WITH VIRGA.
EXPECT MORE THUNDERSTORM DEVELOPMENT OVER THE NEXT TWO HOURS IN THE
CENTRAL CWA...ESPECIALLY BETWEEN THE PRE-FRONTAL TROUGH AND MAIN
TROUGH WHERE THERE IS A PLUME OF HIGHER CAPE VALUES PER LATEST SPC
MESOSCALE ANALYSIS. POTENTIAL FOR SEVERE STORMS IS HIGHEST AS THIS
CORRIDOR SHIFTS INTO SOUTHEAST WI BETWEEN 21Z AND 00Z THIS
AFTERNOON. VERY ISOLATED ONE-INCH HAIL AND DAMAGING WIND GUSTS TO 60
MPH WOULD BE THE SEVERE THREAT. THERE IS NOT ENOUGH 6KM BULK SHEAR
OR LOW LEVEL SHEAR TO SUPPORT WELL-ORGANIZED SUPERCELLS OR
LONG-LIVED STORMS THAT WOULD PRODUCE WIDESPREAD SEVERE STORMS.
17Z HRRR CONTINUES TO SHOW A N-S ORIENTED UNORGANIZED LINE OF
THUNDERSTORMS THAT DEVELOP EAST OF MADISON AT 20Z AND TRACK DUE EAST
TO THE SHORELINE AT 23Z. MODELS AGREE ON ALL TSTORMS OUT OF CWA BY
00Z. LEFT SMALL CHANCE POPS IN THE FAR EAST THROUGH 03Z TO ACCOUNT
FOR POSSIBLE SLOWER MOVEMENT...THEN DRY WEATHER FOR THE REST OF THE
NIGHT.
.TONIGHT AND MONDAY...FORECAST CONFIDENCE HIGH.
VISIBLE SATELLITE AND SURFACE OBSERVATIONS SHOW PLENTY OF CLOUDS
BEHIND THE COLD FRONT THIS AFTERNOON...BUT THESE MIGHT SCATTER OUT
THIS EVENING WITH THE LOSS OF DAYTIME HEATING AND THE STEEP LOW
LEVEL LAPSE RATES...IN COMBINATION WITH SUBSIDENCE BEHIND THE FRONT.
THIS MEANS THAT THERE IS AN OUTSIDE CHANCE THAT PEOPLE IN SOUTHERN
WI COULD VIEW THE PARTIAL SOLAR ECLIPSE EARLY THIS EVENING...
FILTERED THROUGH THE THINNER CLOUDS.
A SECONDARY 500MB TROUGH WILL TRACK ACROSS WI BETWEEN MIDNIGHT
TONIGHT AND NOON MONDAY. TOO DRY FOR PRECIP. A PERIOD OF LOW STRATUS
IS EXPECTED WITH THIS FEATURE IN COMBINATION WITH COLD AIR
ADVECTION...AND THEN SKIES SHOULD CLEAR FROM WEST TO EAST JUST AFTER
SUNRISE MONDAY MORNING. EXPECT DIURNAL CUMULUS CLOUDS TO DEVELOP IN
THE EARLY AFTERNOON.
WINDS WILL BE GUSTY OUT OF THE NORTH MONDAY MORNING WITH THE COLD
AIR ADVECTION AND STEEP LOW LEVEL LAPSE RATES. WINDS WILL TAPER OFF
IN THE AFTERNOON AS HIGH PRESSURE MOVES OVER WISCONSIN. A LAKE
BREEZE WILL DEVELOP WITH THE WEAKENING PRESSURE GRADIENT AND KEEP
AREAS NEAR THE LAKE IN THE LOWER 60S/POSSIBLY UPPER 50S. INLAND
TEMPS SHOULD MAKE IT UP TO AROUND 70.
.MONDAY NIGHT THROUGH WEDNESDAY...FORECAST CONFIDENCE IS HIGH.
HIGH PRESSURE MOVES OVERHEAD MONDAY NIGHT...SLIPPING SOUTHEAST OF
WISCONSIN BY EARLY TUESDAY EVENING WITH RETURN FLOW BRINGING
WARMER TEMPS TO THE AREA ON WEDNESDAY. DRY THROUGH THIS PERIOD. A
LAKE BREEZE WILL BE FELT TUESDAY AND WEDNESDAY FOR COOLER READINGS
ALONG THE LAKE MICHIGAN SHORE. DWPNTS SHOULD MIX OUT DURING THE
DAY...SETTING UP SOME DECENT COOLING POTENTIAL BOTH MONDAY NIGHT
AND TUESDAY NIGHT.
.THURSDAY THROUGH SATURDAY...FORECAST CONFIDENCE LOW TO MEDIUM.
THE ECMWF/GFS/CANADIAN NH ARE GETTING INTO BETTER AGREEMENT WITH
THE LATE WEEK/MEMORIAL DAY WEEKEND PERIOD...AND IT IS THE
ECMWF/CANADIAN THAT ARE COMING IN LINE WITH THE GFS. THERE ARE
TIMING DIFFERENCES...BUT THEY ALL EVENTUALLY BRING A FRONT THROUGH
THE AREA...PUTTING A DAMPER ON THE ONCE EXPECTED VERY WARM
WEEKEND...AT LEAST FOR THE START OF IT. WILL HAVE A SMALL CHANCE
OF SHOWERS AND STORMS REACHING THE FORECAST AREA ON THURSDAY...BASED
ON THE FASTER GFS/CANADIAN WITH THE APPROACHING TROF/FRONT. THE
ECMWF IS DRY FOR THURSDAY...THAT MAY WELL BE TRUE.
THE ASSOCIATED LOW PRESSURE SYSTEM WITH THIS SYSTEM WILL LIFT
NORTHEAST OF THE AREA...DRAGGING A COLD FRONT THROUGH SOUTHERN
WISCONSIN PROBABLY BY FRIDAY MORNING. THIS WILL PUSH THE WARM/HOT
TEMPS SOUTH OF THE BORDER...PUTTING US IN A COOLER NORTHERLY
FLOW. THE BOUNDARY REMAINS TO THE SOUTH OF WISCONSIN THROUGH
SATURDAY WITH A COOL EAST TO NORTHEAST SETTLING IN KEEPING THE
STATIONARY SFC FRONT SOUTH OF WISCONSIN FOR THE FIRST PART OF THE
WEEKEND. IN ADDITION...WITH THE BAROCLINIC ZONE IN THE VCNTY...WE
COULD SEE SOME SHOWERS AND STORMS FROM TIME TO TIME THROUGH FRIDAY
NIGHT.
THE FRONT COULD LIFT NORTH BY SUNDAY AS SOUTHERLY WINDS INCREASE
WITH LOW PRESSURE DEVELOPING WEST OF WISCONSIN. THIS WOULD BRING
THE WARM SECTOR BACK IN FOR WARMER AND DRY CONDITIONS FOR SUNDAY
AND MEMORIAL DAY.
&&
.AVIATION/00Z TAFS/...
CONVECTION AHEAD OF A COLD FRONT MOVING ACROSS WI THIS AFTERNOON.
BULK OF THUNDERSTORMS WILL BE EAST OF MADISON BETWEEN 21Z AND
23Z...EXITING FAR EASTERN WI BY 00Z. THERE IS UNCERTAINTY ABOUT
COVERAGE OF THESE THUNDERSTORMS...AS STRONGEST FORCING WILL BE NORTH
AND SOUTH OF THE TAF SITES. SHORT TERM MODELS SUGGEST AN UNORGANIZED
LINE OF MULTI-CELL THUNDERSTORMS ORIENTED NORTH-SOUTH TRACKING
STRAIGHT EAST.
WEAK SHEAR SHOULD INHIBIT STRONG AND LONG-LASTING THUNDERSTORM
DEVELOPMENT THIS AFTERNOON...HOWEVER SHORT BURSTS OF MARGINALLY
SEVERE HAIL AND DAMAGING WINDS ARE NOT OUT OF THE QUESTION WITH ANY
STRONGER STORMS.
WEST WINDS WILL DECREASE DURING THE EVENING AND BECOME NORTH BY
MONDAY MORNING. THE NORTH WINDS WILL BE GUSTY DURING THE MORNING
HOURS WITH COLD AIR ADVECTION BEHIND DEPARTING LOW PRESSURE SYSTEM.
THEN WINDS WILL DECREASE IN THE AFTERNOON AS HIGH PRESSURE SETTLES
INTO WI.
CLOUDS SHOULD SCATTER OUT FOR A PERIOD OF TIME BEHIND THE FRONT
EARLY THIS EVENING. THEN A PERIOD OF LOW STRATUS IN THE FUEL
ALTERNATE CATEGORY IS EXPECTED WITH THIS FEATURE IN COMBINATION WITH
COLD AIR ADVECTION...AND THEN SKIES SHOULD CLEAR FROM WEST TO EAST
JUST AFTER SUNRISE MONDAY MORNING. EXPECT VFR DIURNAL CUMULUS CLOUDS
TO DEVELOP IN THE EARLY AFTERNOON.
&&
.MARINE...
WINDS HAVE POTENTIAL TO FREQUENTLY GUST TO 25 KNOTS FOR A 4 TO 6
HOUR PERIOD OF TIME MONDAY MORNING IN THE WAKE OF THE DEPARTING LOW
PRESSURE SYSTEM. HIGHEST RISK OF SMALL CRAFT ADVISORY CONDITIONS
WILL BE FROM THE NORTH POINT LIGHT AND SOUTHWARD. TOO MARGINAL AT
THIS TIME TO ISSUE A HEADLINE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/MONDAY AND AVIATION/MARINE...MRC
MONDAY NIGHT THROUGH SUNDAY...DAVIS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
321 PM CDT SUN MAY 20 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
321 PM CDT SUN MAY 20 2012
AFTER AN ACTIVE EARLY AFTERNOON...MAIN FORECAST CONCERNS SWITCH TO
TEMPERATURES THROUGH THE ENTIRE SHORT TERM PERIOD.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING BUILDING UP OVER THE WESTERN U.S....A SHORTWAVE
TROUGH OVER MINNESOTA INTO WESTERN WISCONSIN...AND UPPER RIDGING
OVER THE EASTERN GREAT LAKES. DPVA AHEAD OF THE SHORTWAVE TROUGH...
COMBINED WITH INSTABILITY AND A SURFACE COLD FRONT TO ACT AS A
TRIGGER MECHANISM...HAS LED TO THE DEVELOPMENT OF A LINE OF SHOWERS
AND THUNDERSTORMS. THIS LINE AND COLD FRONT STRETCHES ALONG I-39 IN
WISCONSIN. MLCAPE VALUES OF 1000-1500 J/KG ARE PRESENT AHEAD OF THE
COLD FRONT. OTHER SHOWERS WERE PRESENT OVER NORTHWEST WISCONSIN...IN
AN AREA OF DEFORMATION ON THE NORTHWEST SIDE OF A SURFACE LOW IN
NORTHEAST WISCONSIN. MUCH OF THE FORECAST AREA NOW LIES IN COLD
ADVECTION BEHIND THE COLD FRONT...ALONG WITH A LOT OF STRATUS STUCK
IN THE FRONTAL INVERSION AS INDICATED ON THE 12Z MPX SOUNDING AT
915MB. A LITTLE LIGHT SHOWER/DRIZZLE ACTIVITY IS OCCURRING FROM
THESE CLOUDS TOO. TEMPERATURES HAVE FALLEN INTO THE UPPER 50S ACROSS
MUCH OF SOUTHEAST MINNESOTA...ABOUT 30 DEGREES COLDER THAN THIS TIME
YESTERDAY! CLOUDS CLEAR OUT BACK OVER WESTERN MINNESOTA AND THE
DAKOTAS WHERE DRIER AIR IS PRESENT...SEEN ON THE 12Z BIS AND ABR
SOUNDINGS. 850MB TEMPS DROP OFF QUITE A BIT TOO OVER THE
DAKOTAS...AROUND 6C AT BIS AND ABR COMPARED TO 16C AT GRB AND DVN
PER 12Z SOUNDINGS.
TONIGHT AND MONDAY...HIGH PRESSURE OVER THE DAKOTAS WILL SLIDE EAST
INTO THE FORECAST AREA ON MONDAY...IN THE WAKE OF THE CURRENT
SHORTWAVE TROUGH MOVING INTO MICHIGAN. SUBSIDENCE IN THE WAKE OF THE
TROUGH COMBINED WITH DRY AIR ADVECTION WILL ALLOW THE CLOUDS TO
GRADUALLY CLEAR OUT TONIGHT. MAY STILL BE DEALING WITH SOME
DEFORMATION LIGHT SHOWERS OVER TAYLOR AND CLARK COUNTIES THIS
EVENING...BUT EXPECT THESE TO END AS WELL WITH THE EASTWARD MOVEMENT
OF THE TROUGH. THIS LEAVES TEMPERATURES THE MAIN CONCERN. LOWS THIS
MORNING UNDER THE SURFACE HIGH WERE IN THE UPPER 30S. SINCE THE
HIGH REALLY DOES NOT BUILD INTO THE AREA TONIGHT...NOT
ANTICIPATING THE LOWS TO GET QUITE THAT COOL. HOWEVER...LOW TO
MIDDLE 40S DO SEEM LIKELY. PLENTY OF SUN ON MONDAY...COMBINED WITH
850MB TEMPS AROUND 6C AT MID DAY AND DRY AIR FOR GOOD MIXING
SUPPORT HIGHS REACHING THE LOWER 70S IN MOST LOCATIONS.
MONDAY NIGHT AND TUESDAY...UPPER RIDGING THAT HAS BEEN BUILDING OVER
THE WESTERN U.S. IS FORECAST TO BUILD INTO THE FORECAST AREA ON
TUESDAY...IN RESPONSE TO SOME FAIRLY DEEP TROUGHING DROPPING DOWN
INTO THE PACIFIC NORTHWEST. ALL MODELS AGREE THAT A DEEP LOW AROUND
OR JUST BELOW 990MB FORMS IN THE DAKOTAS DOWNSTREAM OF THIS
TROUGHING. STRENGTHENING WARM ADVECTION AHEAD OF THIS LOW AND
RIDGING BUILDING IN IS LIKELY TO RESULT IN AN EXPANSIVE AREA OF
ALTOSTRATUS AND CIRROSTRATUS. GOOD AGREEMENT EXISTS THAT THESE
CLOUDS WILL SPREAD INTO THE FORECAST AREA MONDAY NIGHT...THEN SLOWLY
SHIFT OFF TO THE EAST ON TUESDAY. RAISED CLOUD COVER CONSIDERABLY
GIVEN THE GOOD MODEL AGREEMENT ON THIS MOISTURE/CLOUDS. NO
ISENTROPIC LIFT IS NOTED WHERE THE CLOUD DECK EXISTS...THEREFORE
HAVE KEPT THE FORECAST DRY. TEMPERATURES ARE DEFINITELY
TRICKY...ESPECIALLY MONDAY NIGHT OVER WISCONSIN. WITH HIGH PRESSURE
AND DRY AIR IN PLACE OVER WISCONSIN MONDAY NIGHT...COULD SEE
TEMPERATURES DROP QUICKLY. THE CLOUDS THEN MOVE IN LATE IN THE
NIGHT. HAVE ONLY DROPPED LOWS TO NEAR 40 IN THE TYPICAL COLD SPOTS
OF WISCONSIN. SHOULD THE CLOUDS BE DELAYED...SOME FROST MENTION
WOULD BE NEEDED. TEMPERATURES MAY RISE LATE IN THE NIGHT OUT IN
SOUTHEAST MINNESOTA AS THE HIGH DEPARTS. STRENGTHENING SOUTHERLY
WINDS ON TUESDAY DUE TO A TIGHTENING PRESSURE GRADIENT...INCREASING
SUNSHINE ESPECIALLY WEST OF THE MISSISSIPPI RIVER...AND 850MB TEMPS
CLIMBING TO 10-14C BY 00Z SUPPORT HIGHS IN THE LOW 70S EAST TO NEAR
80 FAR WEST.
TUESDAY NIGHT AND WEDNESDAY...TROUGHING IS PROGGED TO CONTINUE TO
DEEPEN OVER THE WESTERN U.S. DURING THIS PERIOD...WHILE A MULTITUDE
OF SHORTWAVES EJECT OUT OF THIS TROUGH TOWARDS SOUTH CENTRAL CANADA.
THESE SHORTWAVES WILL HELP TO PUSH THE LOW INTO SOUTHEAST MANITOBA
BY 00Z THURSDAY...AND DRAG ITS COLD FRONT AT LEAST TO NEAR I-35...IF
NOT SLIGHTLY FARTHER EAST AS PROGGED BY THE 20.12Z NAM. A BIG HEAT
PLUME DEVELOPS UNDER THE LOW ON TUESDAY WHICH GETS SHUNTED EAST OVER
OUR AREA ON WEDNESDAY. 850MB TEMPS CLIMB TO AT LEAST 16-18C...IF NOT
HIGHER. IF PLENTY OF SUN OCCURS ON WEDNESDAY...GIVEN A TIGHT
PRESSURE GRADIENT IN PLACE TO MAINTAIN STRONG WINDS FOR MIXING...WE
COULD PUSH 90 AGAIN. HOWEVER...UPPER LEVEL RH PROGS SUGGEST WE MAY
BE DEALING WITH A LOT OF CIRRUS...TEMPERING THE HIGHS SOME.
CERTAINLY TUESDAY NIGHT WILL BE ABOVE NORMAL GIVEN THE BREEZY
SOUTHERLY FLOW FORECAST. LEANED TOWARD THE HIGH SIDE OF GUIDANCE FOR
LOWS. REGARDING PRECIPITATION CHANCES...WE WILL HAVE TO WAIT FOR THE
FRONT TO APPROACH GIVEN THE AREA BEING IN THE WARM SECTOR. SOME
CONCERN EXISTS THAT THE FRONT MAY NOT EVEN GET HERE AS REFERENCED
EARLIER...WITH EVEN THE 20.12Z ECMWF SLOWER STILL. THEREFORE...HAVE
KEPT PRECIPITATION CHANCES MAINLY TO THE AFTERNOON...DOWN NEAR 20
PERCENT...AND FOR WESTERN PORTIONS OF SOUTHEAST MINNESOTA ONLY.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
321 PM CDT SUN MAY 20 2012
THE LONG TERM FORECAST CONTINUES TO REMAIN PROBLEMATIC...WITH ISSUES
ON WHEN THE FRONT FROM WEDNESDAY MOVES INTO THE FORECAST AREA...THEN
POSSIBLE SUMMER HEAT FOR THE WEEKEND.
GOOD MODEL AGREEMENT EXISTS THAT ANOTHER SHORTWAVE EJECTING OUT OF
THE WESTERN TROUGH WILL DEVELOP A SURFACE LOW IN WESTERN KANSAS
WEDNESDAY EVENING. AS THIS SHORTWAVE LIFTS NORTHEAST...SO DOES THE
LOW...CAUSING THE WEDNESDAYS COLD FRONT EASTWARD PROGRESS TO STALL.
THE 20.12Z GEM IS BY FAR THE FASTEST BRINGING THIS SYSTEM
NORTHEAST...CROSSING THE AREA BY 18Z THURSDAY. MEANWHILE...THE GFS
JUST HAS IT GETTING INTO SOUTHEAST MINNESOTA AT 18Z THURSDAY AND THE
NEW 20.12Z ECMWF STILL HAS IT BACK IN NORTHWEST IOWA. THE VARIOUS
SPEEDS HAVE A GREAT IMPACT ON BOTH TEMPERATURES AND WHEN DPVA AND
POSSIBLY FRONTAL FORCED SHOWERS AND THUNDERSTORMS MOVE THROUGH. FOR
NOW...HAVE WENT TOWARDS A CONSENSUS SOLUTION WITH A SLIGHT LEAN
TOWARDS THE SLOWER GFS/ECMWF. THE ECMWF HAS BEEN VARYING BACK AND
FORTH TOO ON THE SPEED OF THIS SYSTEM.
NEXT PROBLEM FOR THURSDAY NIGHT AND RIGHT INTO THE WEEKEND IS THE
LOW PRESSURE SYSTEMS COLD FRONT AND HOW FAR SOUTH IT ENDS UP.
THIS ALL DEPENDS ON HOW FAST/MUCH RIDGING BUILDS OVER THE
MID-MISSISSIPPI VALLEY DOWNSTREAM OF A WELL AGREED UPON DEEP TROUGH
THAT FORMS NEAR CALIFORNIA. THE NEW 20.12Z ECMWF IS STRONGER THAN
ITS PREVIOUS RUN WITH THIS RIDGING...ALLOWING THE FRONT TO ONLY
STALL IN SOUTHERN IOWA BY FRIDAY EVENING. THE 20.12Z GEM IS SIMILAR.
ON THE OTHER HAND...THE GFS REMAINS FARTHER SOUTH DROPPING INTO
SOUTHERN MISSOURI. A CONSENSUS OF THE LAST 6 ECMWF RUNS AND TRENDS
IN THE CFSV2 MODEL SUGGEST A LEAN TOWARDS THE STRONGER RIDGING WOULD
BE PRUDENT. THEREFORE...THE FORECAST FROM THURSDAY NIGHT AND BEYOND
FOLLOWS AN OVERALL MODEL CONSENSUS WITH A LEAN TOWARDS THE 20.12Z
ECMWF. NO MATTER WHAT SOLUTION IS FOLLOWED...THE FRONT WILL MOVE
BACK NORTH AS A WARM FRONT AS THE WESTERN TROUGH SLOWLY PUSHES EAST.
MUCH OF THE EXTENDED HAS 20-40 PERCENT CHANCES FOR PRECIPITATION...
DUE TO TIMING ISSUES WITH THE WEDNESDAY NIGHT/THURSDAY/THURSDAY
NIGHT SYSTEM AND THEN THE FRONTAL BOUNDARY EVENTUALLY LIFTING BACK
NORTH FOR THE WEEKEND. IT DOES APPEAR THAT THE FRONTAL BOUNDARY MAY
GET CAPPED OFF TOWARDS SATURDAY NIGHT...ESPECIALLY SOUTH OF
I-90...SO A DRIER FORECAST IS IN PLACE THERE. TEMPERATURES SHOULD
STAY ABOVE NORMAL...AND POSSIBLY IF THE ECMWF IS RIGHT TO CLIMB INTO
THE 90S FOR SUNDAY. WILL NOT GO THAT HIGH BECAUSE OF THE VARYING
MODEL DIFFERENCES THAT EXIST.
&&
.AVIATION...THROUGH 18Z MONDAY
1239 PM CDT SUN MAY 20 2012
COLD FRONT QUICKLY MOVING EAST INTO WESTERN WISCONSIN THIS
AFTERNOON. SCATTERED THUNDERSTORMS AREA DEVELOPING AHEAD OF THIS
FRONT. A FEW OF THESE THUNDERSTORMS MAY BECOME SEVERE WITH LARGE
HAIL AND DAMAGING WINDS THE MAIN THREATS MAINLY EAST OF AN
EAU CLAIRE TO LANCASTER WISCONSIN LINE. SINCE THIS FRONT WILL BE
SHORTLY PASSING THROUGH KLSE DID NOT INCLUDE THE MENTION OF
THUNDER IN THE TAF.
BEHIND THE COLD FRONT IFR/MVFR CEILINGS EXIST. THESE LOW CLOUDS
HAVE ALREADY MOVED INTO KRST AND THEY WILL BE IN KLSE SHORTLY.
THESE LOW CLOUDS WILL PERSIST THROUGH 21.00Z AT KRST AND THROUGH
21.02Z AT KLSE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
321 PM CDT SUN MAY 20 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
317 PM CDT SUN MAY 20 2012
...THIS AFTERNOON INTO EARLY EVENING...FORECAST CONFIDENCE MEDIUM.
SURFACE CONVERGENCE RIGHT ALONG THE PRE-FRONTAL TROUGH LOCATED NEAR
MADISON AND JANESVILLE AT 230 PM...IDENTIFIED BY A WIND SHIFT IN THE
SURFACE OBS...WILL BE THE FOCUS FOR SOME INITIAL CONVECTION PRIOR TO
THE MAIN FRONTAL BOUNDARY LOCATED IN THE FAR WESTERN FORECAST AREA
/CWA/...WHERE THERE IS ANOTHER WIND SHIFT. A FEW QUICK-MOVING POP-UP
SHOWERS WITH ISOLATED THUNDER ARE DEVELOPING JUST AHEAD OF THE
PRE-FRONTAL TROUGH EARLY THIS AFTERNOON AS WELL. THESE ARE A RESULT
AS GENERAL INSTABILITY WITH MIXED LAYER CAPE AROUND 1000 J/KG.
STEEP LOW LEVEL LAPSE RATES WITH A WELL-MIXED LAYER UP TO 7000 FEET
ARE ALLOWING FOR WINDS GUSTING UP TO 30 KNOTS. EXPECT HIGHER GUSTS
BENEATH SHOWERS WITH VIRGA.
EXPECT MORE THUNDERSTORM DEVELOPMENT OVER THE NEXT TWO HOURS IN THE
CENTRAL CWA...ESPECIALLY BETWEEN THE PRE-FRONTAL TROUGH AND MAIN
TROUGH WHERE THERE IS A PLUME OF HIGHER CAPE VALUES PER LATEST SPC
MESOSCALE ANALYSIS. POTENTIAL FOR SEVERE STORMS IS HIGHEST AS THIS
CORRIDOR SHIFTS INTO SOUTHEAST WI BETWEEN 21Z AND 00Z THIS
AFTERNOON. VERY ISOLATED ONE-INCH HAIL AND DAMAGING WIND GUSTS TO 60
MPH WOULD BE THE SEVERE THREAT. THERE IS NOT ENOUGH 6KM BULK SHEAR
OR LOW LEVEL SHEAR TO SUPPORT WELL-ORGANIZED SUPERCELLS OR
LONG-LIVED STORMS THAT WOULD PRODUCE WIDESPREAD SEVERE STORMS.
17Z HRRR CONTINUES TO SHOW A N-S ORIENTED UNORGANIZED LINE OF
THUNDERSTORMS THAT DEVELOP EAST OF MADISON AT 20Z AND TRACK DUE EAST
TO THE SHORELINE AT 23Z. MODELS AGREE ON ALL TSTORMS OUT OF CWA BY
00Z. LEFT SMALL CHANCE POPS IN THE FAR EAST THROUGH 03Z TO ACCOUNT
FOR POSSIBLE SLOWER MOVEMENT...THEN DRY WEATHER FOR THE REST OF THE
NIGHT.
.TONIGHT AND MONDAY...WILL BE UPDATED SOON.
.MONDAY NIGHT THROUGH WEDNESDAY...FORECAST CONFIDENCE IS HIGH.
HIGH PRESSURE MOVES OVERHEAD MONDAY NIGHT...SLIPPING SOUTHEAST OF
WISCONSIN BY EARLY TUESDAY EVENING WITH RETURN FLOW BRINGING
WARMER TEMPS TO THE AREA ON WEDNESDAY. DRY THROUGH THIS PERIOD. A
LAKE BREEZE WILL BE FELT TUESDAY AND WEDNESDAY FOR COOLER READINGS
ALONG THE LAKE MICHIGAN SHORE. DWPNTS SHOULD MIX OUT DURING THE
DAY...SETTING UP SOME DECENT COOLING POTENTIAL BOTH MONDAY NIGHT
AND TUESDAY NIGHT.
.THURSDAY THROUGH SATURDAY...FORECAST CONFIDENCE LOW TO MEDIUM.
THE ECMWF/GFS/CANADIAN NH ARE GETTING INTO BETTER AGREEMENT WITH
THE LATE WEEK/MEMORIAL DAY WEEKEND PERIOD...AND IT IS THE
ECMWF/CANADIAN THAT ARE COMING IN LINE WITH THE GFS. THERE ARE
TIMING DIFFERENCES...BUT THEY ALL EVENTUALLY BRING A FRONT THROUGH
THE AREA...PUTTING A DAMPER ON THE ONCE EXPECTED VERY WARM
WEEKEND...AT LEAST FOR THE START OF IT. WILL HAVE A SMALL CHANCE
OF SHOWERS AND STORMS REACHING THE FORECAST AREA ON THURSDAY...BASED
ON THE FASTER GFS/CANADIAN WITH THE APPROACHING TROF/FRONT. THE
ECMWF IS DRY FOR THURSDAY...THAT MAY WELL BE TRUE.
THE ASSOCIATED LOW PRESSURE SYSTEM WITH THIS SYSTEM WILL LIFT
NORTHEAST OF THE AREA...DRAGGING A COLD FRONT THROUGH SOUTHERN
WISCONSIN PROBABLY BY FRIDAY MORNING. THIS WILL PUSH THE WARM/HOT
TEMPS SOUTH OF THE BORDER...PUTTING US IN A COOLER NORTHERLY
FLOW. THE BOUNDARY REMAINS TO THE SOUTH OF WISCONSIN THROUGH
SATURDAY WITH A COOL EAST TO NORTHEAST SETTLING IN KEEPING THE
STATIONARY SFC FRONT SOUTH OF WISCONSIN FOR THE FIRST PART OF THE
WEEKEND. IN ADDITION...WITH THE BAROCLINIC ZONE IN THE VCNTY...WE
COULD SEE SOME SHOWERS AND STORMS FROM TIME TO TIME THROUGH FRIDAY
NIGHT.
THE FRONT COULD LIFT NORTH BY SUNDAY AS SOUTHERLY WINDS INCREASE
WITH LOW PRESSURE DEVELOPING WEST OF WISCONSIN. THIS WOULD BRING
THE WARM SECTOR BACK IN FOR WARMER AND DRY CONDITIONS FOR SUNDAY
AND MEMORIAL DAY.
&&
.AVIATION/00Z TAFS/...COMING SOON.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/MONDAY AND AVIATION/MARINE...MRC
MONDAY NIGHT THROUGH SUNDAY...DAVIS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
238 PM CDT SUN MAY 20 2012
.SHORT TERM...TONIGHT AND MONDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE
MOVING NORTHEAST OVER CENTRAL WISCONSIN EARLY THIS AFTERNOON...JUST
AHEAD OF A SHORTWAVE TROUGH OVER EASTERN MINNESOTA. LINES OF
CONVECTION DEVELOPED AHEAD OF THIS SHORTWAVE TROUGH OVER
NORTH-CENTRAL AND NORTHWEST WISCONSIN BY MIDDAY WHERE WIND DAMAGE
AND HALF INCH HAIL OCCURRED EARLIER. INTENSIFICATION OF THE STORMS
REMAINS POSSIBLE THROUGH THE AFTERNOON...AS THE STORMS ENCOUNTER THE
INSTABILITY AXIS FROM WAUSHARA TO LAND O LAKES WHERE ML CAPES RANGE
FROM 1000-1500 J/KG. CAPES MAY NOT GET AS HIGH AS PREVIOUSLY
THOUGHT...SINCE SOME DRIER AIR IS MIXING DOWN TO THE SURFACE. DEEP
LAYER SHEAR REMAINS ABOUT 30-35 KTS...THOUGH THE VAD IS PICKING UP
ON 40KTS AT 2KFT. DAMAGING WIND GUSTS AND LARGE HAIL WILL REMAIN
THE PRIMARY THREATS WITH THE STORMS UNTIL THE SURFACE LOW AND COLD
FRONT DEPART EARLY THIS EVENING.
TONIGHT...LOW PRESSURE WILL MOVE NORTHEAST TONIGHT FROM FAR
NORTHEAST WISCONSIN TO EASTERN LAKE SUPERIOR. THE FRONT WILL STILL
HAVE TO CLEAR DOOR COUNTY AND WILL LEAVE LIKELY POPS FOR THE FIRST
PART OF THE EVENING. BEHIND THE FRONT...THINK WILL SEE SCATTERED
SHOWERS AND ISOLD THUNDERSTORMS EARLY THIS EVENING...THEN LIGHT
SHOWERS THROUGH MIDNIGHT AS COLDER AIR ARRIVES BEHIND THE
FRONT...AND A WIDESPREAD LOW STRATUS DECK SPREADS ACROSS THE AREA.
NORTHERN WISCONSIN MAY SEE THE LIGHT SHOWER ACTIVITY CONTINUE INTO
THE EARLY OVERNIGHT HOURS AS SOUNDINGS STILL LOOK SATURATED UP TO
ABOUT 700MB AT 06Z...BUT WILL GO DRY TO LINE UP WITH SURROUNDING
OFFICES. AT LEAST PARTIAL CLEARING WILL ARRIVE INTO NORTH-CENTRAL
WISCONSIN LATE TONIGHT WHEN DRIER AIR MOVES INTO THAT REGION. LOW
TEMPS RANGING FROM THE LOW 40S NORTH TO LOW 50S SE.
MONDAY...LOW STRATUS WILL PROBABLY HANG ON OVER EASTERN WISCONSIN TO
START THE DAY BUT SHOULD QUICKLY MOVE TO THE EAST DUE TO THE ARRIVAL
OF A MUCH DRIER AIRMASS AND REBOUNDING LOW LEVEL TEMPS. AS SKIES
TURN MOSTLY CLEAR TO PARTLY CLOUDY EVERYWHERE BY LATE IN THE
MORNING...HIGHS WILL REACH FROM THE MIDDLE 60S NORTH TO LOW 70S
SOUTH.
.LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY. A COOL SURFACE HIGH
PRESSURE SYSTEM WITH UPPER RIDGE WILL SETTLE INTO THE AREA FOR THE
FIRST HALF OF THE WORK WEEK WITH QUIET WEATHER AND COMFORTABLE
TEMPERATURES. THE PREVIOUS FORECAST RUN LOWERED TEMPS FOR MONDAY
NIGHT TO WARRANT NON HEADLINE FROST WORDING FOR NORTHERN
WISCONSIN. LATEST RUNS INDICATE LIGHT RETURN FLOW PCPN ALREADY
NEAR THE MN/WI BORDER AT 12Z TUESDAY. CLOUDS MAY ADVANCE INTO
NROTHERN WISCONSIN OVERNIGHT IN THE WESTERLY FLOW TO LIMIT TEMPS
FALLING. THIS TREND SUGGESTS LESS OF A TREND TOWARD ANY FROST
ADVISORY AT THIS TIME SO WILL CONTINUE WITH THE GOING FORECAST.
MAIN FORECAST CHALLENGE ARRIVES LATER IN THE NEW WORK WEEK AS A
BROAD UPPER TROUGH WORKS INTO THE WESTERN STATES AND NORTHERN
PLAINS. MEDIUM RANGE MODELS RUNS IN BETTER AGREEMENT WITH
CONFINING BEST POTENTIAL OF CONVECTION WITH THE RETURN FLOW OVER
THE NORTHERN PLAINS WITH PERHAPS BRUSHING NORTHWEST THIRD OF THE
STATE WEDNESDAY THROUGH WEDNESDAY NIGHT. SHORT WAVE TROUGH WITH
FRONTAL SYSTEM IS PROGGED TO SLIDE OVER STATE SOMETIME FROM
THURSDAY INTO THURSDAY NIGHT TO WARRANT THE HIGHEST PCPN CHC
DURING THIS PERIOD.
FRIDAY INTO SUNDAY...THE REGION WILL BE ON THE NORTHERN PERIPHERY
OF BROAD UPPER RIDGE OVER THE SOUTHERN PLAINS INTO THE SOUTHEAST
STATES. HOWEVER MODELS DIVERT ON CRITICAL LOCATION OF SURFACE
BOUNDARY SEPARATING DEEPER MOISTURE TO THE SOUTH FROM CONTINUED
DRIER CANADA AIR. 00Z ECMWF MAINLY POSITIONS THIS BOUNDARY ALONG
THE WISCONSIN ILLINOIS BORDER WHILE THE GFS IS FURTHER SOUTH. THE
12Z GFS KEEPS THE PCPN SOUTH...WHILE DEVELOPING CONVECTION THIS
SUNDAY AFTERNOON WILL LIKELY PREVENT A CHANCE TO LOOK AT THE
LATEST ECMWF RUN.
&&
.AVIATION...LOW PRESSURE WILL TRACK OVER CENTRAL AND NORTHEAST
WISCONSIN THIS AFTERNOON AND INTO EARLY THIS EVENING. AHEAD OF THE
LOW AND ALONG ITS COLD FRONT...NUMEROUS SHOWERS AND THUNDERSTORMS
WILL DEVELOP EARLY THIS AFTERNOON AND MOVE EAST ACROSS THE AREA
BEFORE EXITING EARLY THIS EVENING. SOME STORMS MAY BECOME SEVERE
WITH DAMAGING WINDS AND LARGE HAIL AS THE PRIMARY THREATS. BEHIND
THE LOW AND FRONT...A WIDESPREAD AREA OF IFR/MVFR STRATUS WILL MOVE
ACROSS THE AREA THROUGH LATE TONIGHT. SCATTERED SHOWERS OR DRIZZLE
WILL BE POSSIBLE OUT OF THIS STRATUS DECK...MAINLY OVER N-C
WISCONSIN. SKY CONDITIONS IMPROVE TOMORROW MORNING TO VFR.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/TDH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
221 PM CDT SUN MAY 20 2012
.SHORT TERM...TONIGHT AND MONDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE
MOVING NORTHEAST OVER CENTRAL WISCONSIN EARLY THIS AFTERNOON...JUST
AHEAD OF A SHORTWAVE TROUGH OVER EASTERN MINNESOTA. LINES OF
CONVECTION DEVELOPED AHEAD OF THIS SHORTWAVE TROUGH OVER
NORTH-CENTRAL AND NORTHWEST WISCONSIN BY MIDDAY WHERE WIND DAMAGE
AND HALF INCH HAIL OCCURRED EARLIER. INTENSIFICATION OF THE STORMS
REMAINS POSSIBLE THROUGH THE AFTERNOON...AS THE STORMS ENCOUNTER THE
INSTABILITY AXIS FROM WAUSHARA TO LAND O LAKES WHERE ML CAPES RANGE
FROM 1000-1500 J/KG. CAPES MAY NOT GET AS HIGH AS PREVIOUSLY
THOUGHT...SINCE SOME DRIER AIR IS MIXING DOWN TO THE SURFACE. DEEP
LAYER SHEAR REMAINS ABOUT 30-35 KTS...THOUGH THE VAD IS PICKING UP
ON 40KTS AT 2KFT. DAMAGING WIND GUSTS AND LARGE HAIL WILL REMAIN
THE PRIMARY THREATS WITH THE STORMS UNTIL THE SURFACE LOW AND COLD
FRONT DEPART EARLY THIS EVENING.
TONIGHT...LOW PRESSURE WILL MOVE NORTHEAST TONIGHT FROM FAR
NORTHEAST WISCONSIN TO EASTERN LAKE SUPERIOR. THE FRONT WILL STILL
HAVE TO CLEAR DOOR COUNTY AND WILL LEAVE LIKELY POPS FOR THE FIRST
PART OF THE EVENING. BEHIND THE FRONT...THINK WILL SEE SCATTERED
SHOWERS AND ISOLD THUNDERSTORMS EARLY THIS EVENING...THEN LIGHT
SHOWERS THROUGH MIDNIGHT AS COLDER AIR ARRIVES BEHIND THE
FRONT...AND A WIDESPREAD LOW STRATUS DECK SPREADS ACROSS THE AREA.
NORTHERN WISCONSIN MAY SEE THE LIGHT SHOWER ACTIVITY CONTINUE INTO
THE EARLY OVERNIGHT HOURS AS SOUNDINGS STILL LOOK SATURATED UP TO
ABOUT 700MB AT 06Z...BUT WILL GO DRY TO LINE UP WITH SURROUNDING
OFFICES. AT LEAST PARTIAL CLEARING WILL ARRIVE INTO NORTH-CENTRAL
WISCONSIN LATE TONIGHT WHEN DRIER AIR MOVES INTO THAT REGION. LOW
TEMPS RANGING FROM THE LOW 40S NORTH TO LOW 50S SE.
MONDAY...LOW STRATUS WILL PROBABLY HANG ON OVER EASTERN WISCONSIN TO
START THE DAY BUT SHOULD QUICKLY MOVE TO THE EAST DUE TO THE ARRIVAL
OF A MUCH DRIER AIRMASS AND REBOUNDING LOW LEVEL TEMPS. AS SKIES
TURN MOSTLY CLEAR TO PARTLY CLOUDY EVERYWHERE BY LATE IN THE
MORNING...HIGHS WILL REACH FROM THE MIDDLE 60S NORTH TO LOW 70S
SOUTH.
.LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY. A COOL SURFACE HIGH
PRESSURE SYSTEM WITH UPPER RIDGE WILL SETTLE INTO THE AREA FOR THE
FIRST HALF OF THE WORK WEEK WITH QUIET WEATHER AND COMFORTABLE
TEMPERATURES. THE PREVIOUS FORECAST RUN LOWERED TEMPS FOR MONDAY
NIGHT TO WARRANT NON HEADLINE FROST WORDING FOR NORTHERN
WISCONSIN. LATEST RUNS INDICATE LIGHT RETURN FLOW PCPN ALREADY
NEAR THE MN/WI BORDER AT 12Z TUESDAY. CLOUDS MAY ADVANCE INTO
NROTHERN WISCONSIN OVERNIGHT IN THE WESTERLY FLOW TO LIMIT TEMPS
FALLING. THIS TREND SUGGESTS LESS OF A TREND TOWARD ANY FROST
ADVISORY AT THIS TIME SO WILL CONTINUE WITH THE GOING FORECAST.
MAIN FORECAST CHALLENGE ARRIVES LATER IN THE NEW WORK WEEK AS A
BROAD UPPER TROUGH WORKS INTO THE WESTERN STATES AND NORTHERN
PLAINS. MEDIUM RANGE MODELS RUNS IN BETTER AGREEMENT WITH
CONFINING BEST POTENTIAL OF CONVECTION WITH THE RETURN FLOW OVER
THE NORTHERN PLAINS WITH PERHAPS BRUSHING NORTHWEST THIRD OF THE
STATE WEDNESDAY THROUGH WEDNESDAY NIGHT. SHORT WAVE TROUGH WITH
FRONTAL SYSTEM IS PROGGED TO SLIDE OVER STATE SOMETIME FROM
THURSDAY INTO THURSDAY NIGHT TO WARRANT THE HIGHEST PCPN CHC
DURING THIS PERIOD.
FRIDAY INTO SUNDAY...THE REGION WILL BE ON THE NORTHERN PERIPHERY
OF BROAD UPPER RIDGE OVER THE SOUTHERN PLAINS INTO THE SOUTHEAST
STATES. HOWEVER MODELS DIVERT ON CRITICAL LOCATION OF SURFACE
BOUNDARY SEPARATING DEEPER MOISTURE TO THE SOUTH FROM CONTINUED
DRIER CANADA AIR. 00Z ECMWF MAINLY POSITIONS THIS BOUNDARY ALONG
THE WISCONSIN ILLINOIS BORDER WHILE THE GFS IS FURTHER SOUTH. THE
12Z GFS KEEPS THE PCPN SOUTH...WHILE DEVELOPING CONVECTION THIS
SUNDAY AFTERNOON WILL LIKELY PREVENT A CHANCE TO LOOK AT THE
LATEST ECMWF RUN.
&&
.AVIATION...LOW PRESSURE WILL TRACK OVER CENTRAL AND NORTHEAST
WISCONSIN THIS AFTERNOON AND INTO EARLY THIS EVENING. AHEAD OF THE
LOW AND ALONG ITS COLD FRONT...NUMEROUS SHOWERS AND THUNDERSTORMS
WILL DEVELOP EARLY THIS AFTERNOON AND MOVE EAST ACROSS THE AREA
BEFORE EXITING EARLY THIS EVENING. SOME STORMS MAY BECOME SEVERE
WITH DAMAGING WINDS AND LARGE HAIL AS THE PRIMARY THREATS. BEHIND
THE LOW AND FRONT...A WIDESPREAD AREA OF IFR/MVFR STRATUS WILL MOVE
ACROSS THE AREA THROUGH LATE TONIGHT. SCATTERED SHOWERS OR DRIZZLE
WILL BE POSSIBLE OUT OF THIS STRATUS DECK...MAINLY OVER N-C
WISCONSIN. SKY CONDITIONS IMPROVE TOMORROW MORNING TO VFR.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/TDH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1234 PM CDT SUN MAY 20 2012
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE.
.UPDATE...LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW
SURFACE LOW PRESSURE MOVING ACROSS WESTERN WISCONSIN AND ITS
TRAILING COLD FRONT EXTENDING SOUTHWEST OVER EASTERN IOWA AND
CENTRAL MISSOURI. ELEVATED CONVECTION IS ONGOING OVER N-C
WISCONSIN IN THE DIVERGENCE REGION AHEAD OF A DECENT LOOKING
SHORTWAVE WHICH IS MOVING NORTHEAST OVER MINNESOTA. MOSTLY CLEAR
SKIES EXIST OVER MUCH OF EASTERN WISCONSIN WHERE TEMPS ARE ALREADY
IN THE LOWER 80S.
THE STORMS NEAR HAYWARD AND MEDFORD WILL PUSH ACROSS NORTH-CENTRAL
WISCONSIN LATER THIS MORNING. MEANWHILE...SURFACE LOW PRESSURE
WILL MOVE NORTHEAST...FROM ABOUT WAUSAU TO IRON MOUNTAIN THIS
AFTERNOON. FURTHER SURFACE DESTABILIZATION ALONG WITH LARGE SCALE
ASCENT VIA SHORTWAVE AND UPPER DIVERGENCE POINTS TOWARDS SURFACE
BASED CONVECTION DEVELOPING EARLY THIS AFTERNOON. BEST GUESS AT
THE MOMENT IS FROM IRON MOUNTAIN TO WAUSHARA CORRIDOR...THEN
TRANSLATING EAST THROUGH THE AFTERNOON. AN 83/61 SURFACE PARCEL
WILL YIELD ABOUT 1700 J/KG OF ML CAPE. DEEP LAYER UNI-DIRECTIONAL
SHEAR OF 25-30 KTS (UP TO 35 KTS OVER FAR NE WISCONSIN) SUPPORTS
ISOLATED TO SLIGHT RISK CHANCES OF SEVERE THUNDERSTORMS. DAMAGING
WIND GUSTS AND LARGE HAIL WILL CONTINUE TO BE THE PRIMARY THREATS.
IF SURFACE WINDS CAN REMAINED BACK OVER FAR NE WISCONSIN DUE TO A
LAKE COMPONENT...MAY ALSO SEE AN ISOLATED TORNADO THREAT DEVELOP...BUT
NOT CONFIDENT IN THIS OCCURRING. THE FRONT STILL LOOKS TO EXIT
EARLY THIS EVENING SO THINK MOST OF THE ACTION WILL OCCUR BEFORE
THAT TIME.
MPC
&&
.PREV DISCUSSION...ISSUED AT 647 AM CDT SUN MAY 20 2012...
SHORT TERM...TODAY THROUGH MONDAY...PCPN TRENDS...THE THREAT OF
SVR TSTMS AND HEAVY RAINFALL THIS AFTERNOON AND EVG...AND TEMPERATURES
ARE THE MAIN FCST CONCERNS.
A COLD FRONT WAS SITUATED FROM WSTRN LK SUP SWWD THROUGH NW WI...
SE MN AND IA. WEAK LOW PRESSURE WAS LIFTING NE ALONG THIS BOUNDARY...
WITH ONE CIRCULATION NEAR MSP AND ANOTHER IN CENTRAL IA. WV IMAGERY
SHOWED A POTENT S/W TROF MOVG THROUGH EASTERN SD/NE...AND HEADED
TOWARD THE WSTRN GREAT LKS. IN ADDITION...THE RRQ OF AN UPPER JET
WAS SITUATED OVER THE UPPER MISS VALLEY...AND WAS PROVIDING THE
FORCING FOR A LARGE AREA OF POST-FRONTAL SHOWERS AND TSTMS OVER
EASTERN SD AND MN. MOISTURE WAS POOLING NEAR THE COLD FRONT...WITH
DEW POINTS IN THE MID 50S TO LOWER 60S. 00Z SOUNDINGS SHOWED PCPN
WATER VALUES 200 PERCENT OF NORMAL OVER MN.
THE COLD FRONT WILL EDGE EAST DURING THE DAY...AS THE S/W TROF
APPROACHES FROM THE SOUTHWEST AND THE RRQ OF THE UPPER JET
POSITIONS ITSELF OVER GRB CWA DURING THE AFTERNOON. PRECIPITABLE
WATER VALUES ARE EXPECTED TO INCREASE TO 150-200 PERCENT OF
NORMAL...WITH SFC DEW POINTS INCREASING INTO THE UPPER 50S AND
LOWER 60S...AND H8 DEW POINTS AROUND 10-12 C. ALTHOUGH MID-LEVEL
CLOUDS WILL LIMIT HEATING TO SOME DEGREE...FILTERED SUNSHINE
SHOULD ALLOW TEMPS TO WARM INTO THE LOW TO MID 80S IN NE/EC WI...
BOOSTING CAPES TO 1500-2000 J/KG THIS AFTERNOON. THE COMBINATION
OF STRONG DYNAMIC FORCING...ABUNDANT MOISTURE AND MODERATE
INSTABILITY SUPPORTS WIDESPREAD SHOWER/TSTM DEVELOPMENT LATER THIS
MORNING AND AFTERNOON. LIKELY POPS ARE WARRANTED OVER THE ENTIRE
CWA...AND HAVE BOOSTED POPS TO CATEGORICAL OVER NC WI. INGREDIENTS
ARE IN PLACE FOR HEAVY RAINFALL...AND A HANDFUL OF REPORTS OF AN
INCH OR GREATER HAVE ALREADY BEEN REPORTED UPSTREAM...INCLUDING A
4+ INCH AMOUNT IN NW IA. HAVE ADDED THE MENTION OF HEAVY RAINFALL
TO THE GRIDS/ZFP. SPC ALSO HAS MUCH OF C/NE/EC WI IN A SLGT RISK
TODAY. NOT CONFIDENT ENOUGH TO MENTION THIS EXPLICITLY IN THE
FCST...DUE TO CONCERNS ABOUT CLOUD COVER...BUT WILL MENTION AT
LEAST AN ISOLD THREAT OF DAMAGING WINDS AND HAIL IN THE HAZARDOUS
WEATHER OUTLOOK. WENT WITH A NON- DIURNAL TEMPERATURE TREND IN THE
GRIDS DUE TO THE FRONTAL PASSAGE/PCPN.
WILL HAVE A DECREASING TREND IN THE PCPN THIS EVG AS THE FRONT
EXITS THE REGION...WITH PARTIAL CLEARING OCCURRING OVERNIGHT.
STAYED CLOSE TO THE PREVIOUS FCST FOR MIN TEMPS...MAINLY 40S AND
LOWER 50S.
ON MONDAY...PARTLY CLOUDY SKIES AND MIXING THROUGH 800-775 MB
SHOULD YIELD MAX TEMPS IN THE UPPER 60S AND LOWER 70S...CLOSER
TO NORMAL.
LONG TERM...MONDAY NIGHT THROUGH SATURDAY.
A QUIET PATTERN EXPECTED MONDAY NIGHT AND TUESDAY AS CANADIAN
HIGH PRESSURE DOMINATES THE WEATHER PATTERN. A COMBINATION OF CLEAR
SKIES...LIGHT WINDS AND DEW POINTS IN THE 30S MONDAY NIGHT WILL
ALLOW TEMPERATURES TO FALL CONSIDERABLY LOWER THAN PREVIOUS FORECAST.
DID LOWER THEM SEVERAL DEGREES AND ALSO MENTIONED AREAS OF FROST
ACROSS THE NORTH. TUESDAY WILL BE SUNNY AND MILD WITH HIGHS IN
THE UPPER 60S TO MIDDLE 70S. THE HIGH WILL SLIDE EAST OF THE
AREA TUESDAY NIGHT AND WEDNESDAY. SOUTHERLY FLOW WILL ALLOW FOR
WARMER TEMPERATURES TO WORK INTO THE AREA.
THE NEXT SYSTEM WILL AFFECT THE AREA FROM LATE WEDNESDAY NIGHT INTO
THURSDAY AND THURSDAY NIGHT. HAVE A HIGH CHANCE FOR SHOWERS AND
THUNDERSTORMS THURSDAY AND THURSDAY NIGHT.
MODEL DIVERGE ON THE DETAILS OF A BUILDING 500MB RIDGE FRIDAY THROUGH
THE MEMORIAL DAY WEEKEND. 00Z GFS NOW HAS THE FRONT WELL SOUTH OF
THE AREA AND TEMPERATURES WOULD BE SOMEWHAT ABOVE NORMAL DESPITE
BEING ON THE COOL SIDE OF THE BOUNDARY. THE ECMWF ON THE OTHER HAND...
HAS THE BOUNDARY LURKING ACROSS THE STATE WITH PERIODIC CHANCES
FOR SHOWERS AND THUNDERSTORMS AS COMPLEXES OF STORMS ROLL ACROSS
THE STATE. THE ECMWF WOULD BE CONSIDERABLY WARMER THAN THE GFS.
THE CANADIAN TRENDED TOWARD THE ECMWF WITH 500MB HEIGHTS...BUT
BOUNDARY WAS JUST TO THE SOUTH OF THE AREA. DID NOT MAKE MANY
CHANGES TO THE FRIDAY AND SATURDAY PERIOD FOR NOW DUE TO THE
DIFFERENCES ON HOW THE MODELS HANDLE THE UPPER LEVEL/SURFACE
FEATURES.
&&
.AVIATION...LOW PRESSURE WILL TRACK OVER CENTRAL AND NORTHEAST
WISCONSIN THIS AFTERNOON AND INTO EARLY THIS EVENING. AHEAD OF THE
LOW AND ALONG ITS COLD FRONT...NUMEROUS SHOWERS AND THUNDERSTORMS
WILL DEVELOP EARLY THIS AFTERNOON AND MOVE EAST ACROSS THE AREA
BEFORE EXITING EARLY THIS EVENING. SOME STORMS MAY BECOME SEVERE
WITH DAMAGING WINDS AND LARGE HAIL AS THE PRIMARY THREATS. BEHIND
THE LOW AND FRONT...A WIDESPREAD AREA OF IFR/MVFR STRATUS WILL MOVE
ACROSS THE AREA THROUGH LATE TONIGHT. SCATTERED SHOWERS OR DRIZZLE
WILL BE POSSIBLE OUT OF THIS STRATUS DECK...MAINLY OVER N-C
WISCONSIN. SKY CONDITIONS IMPROVE TOMORROW MORNING TO VFR.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1206 PM CDT SUN MAY 20 2012
.UPDATE...
TEMPS WARMING QUICKLY THIS MORNING IN THE WARM SECTOR...WITH AN
APPROACHING COLD FRONT LINED UP FROM NW WI TO EASTERN IOWA. BUMPED
UP TEMPS A BIT TO ACCOUNT FOR SEVERAL MORE HOURS OF HEATING BEFORE
THE FRONT ARRIVES.
LAKE BREEZE DEVELOPED ONCE AGAIN TODAY...ALTHOUGH IT IS NOT MAKING
MUCH HEADWAY TOWARD MITCHELL OR KENOSHA AIRPORTS DUE TO THE STRONG
SOUTHWEST SYNOPTIC FLOW.
AS FOR THUNDERSTORM POTENTIAL...DEVELOPMENT IS STILL LIKELY RIGHT
ALONG THE FRONT...WITH SCATTERED TO NUMEROUS COVERAGE. DEWPOINT
TEMPS AROUND 60 IN THE VICINITY OF THE FRONT SHOULD BE ENOUGH TO
SUPPORT AFTERNOON CONVECTION...HOWEVER THE DEWPOINTS ARE MIXING DOWN
INTO THE LOW TO MID 50S ALREADY. UPPER DIVERGENCE FROM THE RIGHT
ENTRANCE REGION OF THE UPPER JET OVERHEAD WILL COINCIDE WITH THE
COLD FRONT. MID LEVEL FORCING WILL BE RATHER WEAK...WITH THE
STRONGEST VORTICITY MAX MOVING ACROSS CENTRAL/NORTHERN WI THIS
AFTERNOON. ANOTHER VORT MAX WILL ROLL ACROSS MO/SOUTHERN IL...AND
SOUTHERN WI WILL BE CAUGHT IN THE WEAKER FORCING AREA.
13Z HRRR AND 12Z LOCAL WRF MODELS SHOW CONVECTION MOVING ACROSS OUR
FORECAST AREA IN A NORTH-SOUTH ORIENTED...UNORGANIZED MULTI-CELL
LINE THIS AFTERNOON...DEVELOPING JUST WEST OF MADISON AROUND 20-21Z
AND REACHING MILWAUKEE AROUND 23Z. THE HRRR MODEL COLUMN MAX
REFLECTIVITY HAS BEEN SHOWING A WEAKENING TREND THE PAST FEW
RUNS...BUT WE SHALL SEE WHAT THE NEXT COUPLE DO.
THERE WILL BE SUFFICIENT CAPE AROUND 1500 J/KG AND ALSO CAPE WITHIN
THE HAIL GROWTH REGION TO SUPPORT HAIL DEVELOPMENT WITH ANY OF THE
STRONGER THUNDERSTORMS THAT DEVELOP LATE THIS AFTERNOON. IN
ADDITION...DAMAGING WIND GUSTS ARE A POSSIBILITY WITH THE STEEP LOW
LEVEL LAPSE RATES. THE LIMITING FACTOR FOR WIDESPREAD SEVERE STORMS
IN OUR AREA WILL BE THE LACK OF WIND SHEAR. 6KM BULK SHEAR WILL BE
IN THE 20 TO 25 KNOT RANGE AT BEST...WHICH WOULD NOT SUSTAIN STRONG
SUPERCELL DEVELOPMENT OR LONG-DURATION STORMS.
THE BEST POTENTIAL FOR SEVERE THUNDERSTORMS WILL BE IN CENTRAL AND
NORTHERN WI...AND OUR FORECAST AREA WILL BE ON THE SOUTHERN
PERIPHERY OF THAT REGION. WILL NOT MAKE CHANGES TO THE FCST POPS FOR
THIS AFTERNOON AT THIS TIME.
&&
.AVIATION/18Z TAFS/...
THE LAKE BREEZE DEVELOPED THIS MORNING...BUT IS STALLED JUST EAST OF
MKE DUE TO THE STRONG SOUTHWEST SYNOPTIC FLOW. CURRENT THINKING IS
THAT THE LAKE BREEZE WILL NOT MAKE IT INLAND TO KENOSHA TO CAUSE THE
WIND SHIFT. THE LAKE BREEZE SHOULD AFFECT MILWAUKEE FOR A COUPLE OF
HOURS...THEN PUSH BACK TOWARD THE LAKE JUST AHEAD OF THE COLD FRONT.
CONVECTION EXPECTED TO DEVELOP JUST AHEAD OF A COLD FRONT MOVING
ACROSS WI THIS AFTERNOON...ARRIVING AT MSN AROUND 20-21Z AND MKE
AROUND 23Z. THERE IS UNCERTAINTY ABOUT COVERAGE OF THESE
THUNDERSTORMS...AS STRONGEST FORCING WILL BE NORTH OF THE TAF
SITES...TOWARD CENTRAL AND NORTHERN WI. SHORT TERM MODELS SUGGEST AN
UNORGANIZED LINE OF MULTI-CELL THUNDERSTORMS ORIENTED NORTH-SOUTH
TRACKING STRAIGHT EAST.
WEAK SHEAR SHOULD INHIBIT STRONG AND LONG-LASTING THUNDERSTORM
DEVELOPMENT THIS AFTERNOON...HOWEVER SHORT BURSTS OF MARGINALLY
SEVERE HAIL AND DAMAGING WINDS ARE NOT OUT OF THE QUESTION WITH ANY
STRONGER STORMS.
&&
.PREV DISCUSSION... /ISSUED 416 AM CDT SUN MAY 20 2012/
TODAY AND TONIGHT...CONFIDENCE...MEDIUM
THE SHORTWAVE TROUGH OVER ERN NE WILL LIFT NEWD TO WEST CENTRAL WI
BY 00Z AND CONTINUE NEWD AFTERWARD BUT ANOTHER WEAK SHORTWAVE
APPROACHING FROM THE NRN PLAINS WILL DROP SEWD INTO SRN WI FOR MON
AM. THE COLD FRONT OVER MN AND IA WILL PROGRESS FROM WEST TO EAST
ACROSS THE CWA FROM 21Z TO 02Z BUT CONVERGENCE AND FRONTOGENESIS IS
EXPECTED TO BE WEAK. VARIOUS MODELS HAVE BACKED OFF SOME ON QPF
PROBABLY DUE TO THE SHORTWAVE TROUGH TRACKING MORE NWD AND THE
AFOREMENTIONED WEAK SFC CONVERGENCE. SATELLITE TRENDS DO INDICATE
GOOD HEATING WILL OCCUR TODAY SO INCREASED TEMPS TO MID TO UPPER 80S
WITH EXPECTED MLCAPE VALUES APPROACHING 1500 J/KG FOR THIS AFTERNOON
WITH LITTLE TO NO CIN. ULTIMATELY WENT WITH LIKELY POPS IN THE NRN
CWA WHERE BETTER PVA WILL AID SFC CONVERGENCE AND CONVECTIVE
INITIATION WHILE GOING WITH 40-50 POPS IN THE SOUTH. SVR POTENTIAL
IS VERY MARGINAL GIVEN WEAK DEEP LAYER WIND SHEAR. THE SHORTWAVE
TROUGH FOR LATE TNT SHOULD NOT HAVE AN IMPACT WITH PCPN BUT WILL
PROBABLY AID IN STRATUS DEVELOPMENT IN THE COLD ADVECTION REGIME.
MONDAY - CONFIDENCE...MEDIUM
SURFACE BOUNDARY TO THE SOUTHEAST TO START THE DAY WITH 850 COOL AIR
ADVECTION BEGINNING. MID LEVEL DRY AIR IS PLENTIFUL. CONCERNED
THOUGH WITH 500 MILLIBAR VORT MAX STILL TO THE WEST AND TROUGH AXIS
NOT TO THE EAST UNTIL THE AFTERNOON. NAM IS THE SLOWEST AND ONLY
MODEL TO GENERATE LINGERING PRECIP. GFS 925-850 RH PROG IS
COMPROMISE WITH REGARD TO MORNING CLOUD TRENDS.
TUESDAY - CONFIDENCE...MEDIUM
MID LEVEL RIDGING BUILDS IN FROM THE WEST. A FEW WEAK RIPPLES IN THE
FLOW. SOUNDINGS LARGELY DRY AND QUITE STABLE...WITH GFS SHOWING SOME
MID LEVEL MOISTURE. SURFACE HIGH PROGGD TO GRADUALLY SHIFT EAST.
WEDNESDAY - CONFIDENCE...MEDIUM
UPPER RIDGE SHIFTS EAST AND BROAD SOUTHWEST FLOW DEVELOPS. WARMER
AIR HEADS NORTH ON SOUTHERLY SURFACE/850 FLOW. 850 TEMPS WELL INTO
THE TEENS. STILL ENOUGH EASTERLY COMPONENT IN THE SOUTHERLY FLOW TO
KEEP THE FAR EASTERN CWA COOLER. PREFER THE DRIER LOOK OF THE
ECMWF/GEM KEEPING PRECIP WELL TO OUR WEST AND NORTHWEST.
THURSDAY AND THURSDAY NIGHT - CONFIDENCE...MEDIUM
UPPER FLOW BECOMES INCREASINGLY CYCLONIC AS TROUGH AXIS DRAWS
CLOSER. SURFACE/850 FRONTS ALSO APPROACH AND INCREASE POTENTIAL FOR
SHRA/TSRA. FAIRLY DECENT AGREEMENT AMONGST THE MODELS WITH THIS
FROPA AND ASSOCIATED QPF FIELDS.
FRIDAY AND SATURDAY - CONFIDENCE...LOW
LOTS OF UNCERTAINTY IN THIS TIME FRAME AS ECMWF BUILDS HEIGHTS WITH
RIDGE RIDERS WHILE GFS HAS A FLATTER FLOW BUT KEEPS PRECIP FURTHER
SOUTH AND WEST CLOSER TO MORE SOUTHERN DISPLACED 850 BAROCLINIC
ZONE. ECMWF SUGGESTING A FEW PERIODS OF STORMS BEFORE FOCUS SHIFTS
FURTHER NORTH WITH THE BUILDING RIDGE AXIS. LARGE TEMPERATURE
SPREAD...AS BIG AS 25 DEGREES...CONTINUES BETWEEN GFS AND ECMWF FOR
SATURDAY. THE ALLBLEND POPS ARE QUITE LOW BOTH FRIDAY AND SATURDAY
AND THIS IS CONCERNING...ESPECIALLY FRIDAY. THIS MAY BE UNDERDONE
BUT WILL LEAVE AS IS FOR NOW BASED ON COLLAB.
AVIATION/12Z TAFS/...LOW LEVEL WIND SHEAR WILL CONTINUE UNTIL
13-14Z WHEN SFC WINDS INCREASE. OTHERWISE BREEZY SLY WINDS AND VFR
CONDITIONS EXPECTED AHEAD OF THE COLD FRONT TODAY. SCT TSTORMS ARE
EXPECTED ALONG THE COLD FRONT FROM MID TO LATE AFTERNOON INTO THE
EVENING. AFTER FROPA...MVFR CIGS WILL DEVELOP WITH CIGS EVENTUALLY
FALLING TO POSSIBLY 1 KFT. THIS WILL CONTINUE FOR MUCH OF THE NIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...GEHRING
MONDAY THROUGH SATURDAY...COLLAR