Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/14/13
AREA FORECAST DISCUSSION
NWS MIAMI FL
922 AM EDT SUN MAY 12 2013
.UPDATE...
NO CHANGES ARE PLANNED FOR THE MORNING UPDATES. THE 12Z MFL
SOUNDING SHOWS ONLY MODEST INSTABILITY WITH TWO SMALL INVERSIONS,
ONE AT AROUND THE 850 MB LEVEL AND ANOTHER AT 500 MB. THUS, IT
WOULD APPEAR THAT CONVECTION WILL STRUGGLE TO GET GOING MUCH LIKE
YESTERDAY AND MAY EVEN BE MORE SO TODAY. MODIFIED CAPE IS AROUND
1500 J/KG OR SLIGHTLY LESS AND THAT IS ALSO SIMILAR TO SATURDAY.
STEERING FLOW REMAINS WNW-ESE AT 5-7 KT AND BASED ON ALL OF THIS
THE HRRR DOES SHOW CONVECTION FIRING UP AT 18-19Z AND THEN
BUILDING AFTER 20Z AS IT DRIFTS TOWARDS THE EAST COAST METRO
REGION. SO ALL IN ALL, THE FORECAST LOOKS GOOD WITH A LATE
AFTERNOON/EARLY EVENING STRONG STORM POSSIBLY CAPABLE OF PRODUCING
A WIND GUST AND/OR SMALL HAIL ALTHOUGH THE PRIMARY RISK APPEARS TO
BE THE WIND GUSTS.
KOB
&&
.PREV DISCUSSION... /ISSUED 720 AM EDT SUN MAY 12 2013/
AVIATION...
CLEAR SKIES AND CALM WINDS THIS MORNING WILL GRADUALLY TRANSITION TO
SCATTERED/BROKEN CUMULUS WITH ONSHORE WINDS OF 10-15 KTS BY MIDDAY.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED AWAY FROM THE GULF
COAST. HAVE ELECTED TO PLACE VCSH AT ALL AIRPORTS EXCEPT KAPF...DUE
TO LOW CONFIDENCE IN COVERAGE AND TIMING OF THUNDERSTORMS. GUSTY
WINDS AND SIGNIFICANT BUT BRIEF FLIGHT RESTRICTIONS COULD OCCUR IN
AND NEAR SHOWERS AND THUNDERSTORMS THIS AFTERNOON. ACTIVITY LIKELY
DIMINISHES BY SUNSET...THEN CLEARING SKIES AND CALM WINDS TONIGHT.
FOG OVER INTERIOR SOUTH FLORIDA COULD IMPACT APF LATE TONIGHT...BUT
ATTM THIS RISK APPEARS LOW.
PREV DISCUSSION... /ISSUED 350 AM EDT SUN MAY 12 2013/
DISCUSSION...
AN UPPER TROUGH WAS DIGGING INTO THE SOUTHEAST THIS
MORNING...WITH MAINLY ZONAL FLOW ACROSS SOUTH FLORIDA. A SURFACE
LOW WAS LOCATED OVER CANADA TO THE NORTH OF THE GREAT LAKES AND A
COLD FRONT WAS MOVING INTO NORTHERN FLORIDA. WINDS NEAR THE
SURFACE ARE EXPECTED TO BE OUT OF THE SOUTH TO SOUTHEAST...WITH
WESTERLY FLOW ALOFT. THE MORE SOUTHERLY LOW LEVEL FLOW WILL PUSH
THE SEA BREEZE BOUNDARY NORTHWARD AWAY FROM THE SOUTHEAST
COAST...AND THE WESTERLY FLOW ALOFT WILL PUSH STORMS BACK TOWARDS
THE EAST COAST. LOW LEVEL MOISTURE WILL POOL SOUTH OF THE FRONTAL
BOUNDARY THIS AFTERNOON...WITH PWATS AROUND 1.6-1.7 INCHES. SO THE
BEST CHANCE OF RAIN WILL BE ACROSS PALM BEACH AND BROWARD
COUNTIES. SHEAR VALUES ARE NOT AS HIGH AS YESTERDAY...AND
TEMPERATURES ALOFT ARE SLIGHTLY WARMER AS WELL. HOWEVER...AS THE
TROUGH DIGS INTO THE SOUTHEAST AND NORTHERN FLORIDA...DIVERGENCE
ALOFT WILL INCREASE. SO STRONG STORMS WILL BE POSSIBLE...AND A
STRAY SEVERE STORM CANNOT BE RULED OUT ACROSS THE INTERIOR AND
ACROSS PALM BEACH COUNTY. THE MAIN THREAT WILL BE STRONG WINDS.
HIGHS WILL BE IN THE MID 80S COASTAL AREAS TO LOWER 90S INTERIOR.
THE FRONTAL BOUNDARY WILL MOVE INTO SOUTH FLORIDA MONDAY
MORNING...AND PATCHY FOG IS POSSIBLE...ESPECIALLY FOR THE
NORTHWESTERN HALF OF THE REGION. ALTHOUGH NOT CURRENTLY IN THE
FORECAST...DENSE FOG COULD ALSO OCCUR ACROSS THE NORTHWEST
INTERIOR. THE UPPER TROUGH WILL DIG DOWN THE PENINSULA...AND THE
REGION WILL MOVE INTO THE RIGHT ENTRANCE REGION OF A 100 KNOT
250MB JET STREAK. 0-6KM SHEAR WILL INCREASE TO AROUND 30 KNOTS AS
WELL. THE SURFACE BOUNDARY IS EXPECTED TO PUSH INTO DEEP SOUTH
FLORIDA AROUND 18Z WITH NORTHERLY LOW LEVEL FLOW. HOWEVER...DRY
AIR WILL LAG BEHIND ACROSS CENTRAL FLORIDA. AS THE EAST COAST SEA
BREEZE DEVELOPS...SCATTERED SHOWERS AND STORMS ARE EXPECTED TO
DEVELOP ALONG IT...WITH STORM MOTION TO THE SOUTH OR SOUTHEAST.
STRONG TO ISOLATED SEVERE STORMS ARE POSSIBLE..ESPECIALLY TOWARDS
THE SOUTHEAST PORTIONS OF THE AREA.
DRIER AIR WILL BEGIN TO MOVE INTO THE LAKE REGION IN THE LATE
AFTERNOON TO EARLY EVENING...WITH MUCH DRIER AIR ENCOMPASSING
SOUTH FLORIDA OVERNIGHT. PRECIPITABLE WATER VALUES WILL DROP TO
AROUND 0.75 INCHES...WHICH IS WELL BELOW NORMAL FOR THIS TIME OF
YEAR. SURFACE HIGH PRESSURE WILL BUILD INTO THE SOUTHEAST AND
WESTERN ATLANTIC...AND BREEZY NORTHEASTERLY WINDS ARE EXPECTED ON
TUESDAY. TEMPERATURES TUESDAY MORNING WILL BE COOLER...ESPECIALLY
ACROSS THE NORTHWEST INTERIOR...WHERE LOWS WILL BE IN THE 50S. MID
60S TO AROUND 70 IS STILL EXPECTED FOR THE EAST COAST...BUT IT
WILL FEEL MUCH MORE COMFORTABLE AS DEWPOINTS DROP INTO THE 50S TO
AROUND 60. VERY PLEASANT MID MAY TEMPERATURES ARE EXPECTED ON
TUESDAY THROUGH THE END OF THE WEEK. HIGHS WILL BE NEAR 80 TO THE
MID 80S ON TUESDAY.
AN UPPER LEVEL RIDGE WILL BUILD TO THE EAST ACROSS THE GULF ON
WEDNESDAY AND HEIGHTS WILL INCREASE. HOWEVER...TEMPERATURES WILL
REMAIN AT OR BELOW NORMAL THROUGH THE END OF THE WEEK AS DRY AND
COOL EAST TO NORTHEASTERLY FLOW CONTINUES. PWATS WILL REMAIN AT
OR BELOW 1 INCH THROUGH THE END OF THE WEEK. A WEAK SHORTWAVE WILL
MOVE ACROSS THE SOUTHERN PLAINS AND INTO THE SOUTHEAST ON
THURSDAY...WITH WEAK TROUGHING THEN REMAINING OVER THE SOUTHEAST
AND FLORIDA INTO THE WEEKEND.
AVIATION...
VFR CONDITIONS WILL PREVAIL THROUGH EARLY THIS WEEK. MOSTLY CLEAR
SKIES AND NEAR-CALM WINDS EARLY THIS MORNING WILL GIVE WAY TO
INCREASING CUMULUS WITH SOUTHEAST BREEZES AT 10-15 KTS BY MIDDAY.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE
AFTERNOON ACROSS SOUTH FLORIDA...MAINLY EAST OF NAPLES.
THUS...PROB30S MAINTAINED FOR EASTERN TERMINALS. GUSTY WINDS AND
SIGNIFICANT BUT BRIEF FLIGHT RESTRICTIONS ARE LIKELY IN/NEAR
SHOWERS/THUNDERSTORMS. PRECIPITATION SHOULD DIURNALLY WANE THIS
EVENING...WITH CLEARING SKIES AND CALMING WINDS EXPECTED TODAY.
MARINE...
TRANQUIL WIND AND SEAS WILL CONTINUE TODAY OUTSIDE OF ISOLATED
STRONG CONVECTION. A COLD FRONT WILL MOVE ACROSS THE SOUTH FLORIDA
WATERS LATE MONDAY WITH STRONG HIGH PRESSURE BUILDING BEHIND THE
FRONT WITH INCREASING WIND AND SEAS MONDAY NIGHT INTO MID WEEK.
FIRE WEATHER...
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY
AND MONDAY...MAINLY DURING THE AFTERNOON AND EARLY EVENING
HOURS. A FRONT WILL BRING IN MUCH DRIER AIR MONDAY NIGHT INTO
TUESDAY. RELATIVE HUMIDITY VALUES ACROSS GLADES HENDRY AND
COLLIER COUNTIES MAY FALL BELOW 35 PERCENT BOTH TUESDAY AND
WEDNESDAY AFTERNOONS...WITH WINDS OF 10-15 MPH POSSIBLE. THERE IS
A SLIGHT CHANCE THAT PATCHY FOG WILL FORM LATE TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 86 69 85 65 / 60 30 30 10
FORT LAUDERDALE 87 74 85 69 / 50 20 50 20
MIAMI 88 72 86 69 / 40 20 50 20
NAPLES 86 71 86 64 / 10 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1235 PM CDT SUN MAY 12 2013
.DISCUSSION...
327 AM CDT
MAIN FORECAST CHALLENGES/CONCERNS ARE WITH THE COLD TEMPS AND
FROST TONIGHT WITH A FROST ADVISORY NOW IN PLACE FOR ALL OF THE
CWA TONIGHT...THE ANTICIPATED WARM UP THIS WEEK...AND SIGNS OF A
MORE ACTIVE WEATHER PATTERN BEGINNING TO APPEAR IN THE EXTENDED.
IN THE NEAR TERM...QUIET WEATHER ONGOING ACROSS THE CWA WITH
MOSTLY CLEAR SKIES IN PLACE OVER MUCH OF NORTHEAST ILLINOIS AND
NORTHWEST INDIANA. THE EXCEPTION IS NEAR THE WISCONSIN BORDER
WHERE MID LEVEL CLOUDS ARE TRYING TO SPILL INTO THE AREA THIS
MORNING. THIS IS IN RESPONSE TO SEVERAL WAVES OF ENERGY DROPPING
SOUTHEAST AROUND THE BASE OF THE STRONG UPPER LEVEL LOW TO THE
NORTHEAST. STEEP LOW/MID LEVEL LAPSE RATES STILL IN PLACE EARLY
THIS MORNING WITHIN THIS CYCLONIC WILL CONTINUE TO ALLOW FOR SOME
SCATTERED CLOUD DEVELOPMENT BUT PRIMARILY FOR AREAS IN FAR
NORTHEAST ILLINOIS...AS THIS LOCATION NORTHWARD IS WHERE THE BEST
FORCING/STEEPER LAPSE CURRENTLY RESIDE. ALTHOUGH THERE MAY BE
PERIODS OF THIS SCATTERED MID DECK OR EVEN AN ISOLATED AND BRIEF
CEILING...THINK SKIES SHOULD REMAIN MORE ON THE CLEARER SIDE
THROUGH MID MORNING. TEMPERATURES RIGHT NOW ARE STILL HOLDING
AROUND 40 DEGREES DESPITE THE CLEAR SKIES AND MUCH COLDER AIRMASS
IN PLACE. AS WAS EXPECTED...THE SURFACE LOW TO THE NORTHEAST WITH
TIGHT PRESSURE GRADIENT OVER THE CWA HAS ALLOWED FOR SURFACE WINDS
TO STAY UP NEAR THE 10KT RANGE. SO ONLY EXPECT TEMPS TO FALL A
COUPLE OF MORE DEGREES HERE THIS MORNING BEFORE RISING TO WELL
BELOW NORMAL MAX TEMPS IN THE LOW TO MID 50S TODAY. SHOULD BE A
RATHER QUIET DAY TODAY...ALTHOUGH LOW LEVEL LAPSE RATES REALLY
STEEPEN UP ONCE AGAIN TODAY ACROSS THE CWA. ONCE AGAIN...THESE
LAPSE RATES WITHIN THIS CYCLONIC FLOW WILL PROVIDE FOR SOME
STRATOCU DEVELOPMENT BY MID TO LATE MORNING WITH ANY CLEAR SKIES
BECOMING BROKEN/PARTLY SUNNY. EXPECT THIS TO BE THE CASE THROUGH
THE AFTERNOON AND INTO THE EARLY EVENING. ALTHOUGH CONDITIONS
APPEAR DRY AT THE MOMENT FOR THIS AFTERNOON...LATEST SHORT TERM
GUIDANCE IS TRYING TO INDICATE SOME ISOLATED SHOWER DEVELOPMENT
ACROSS NORTHEAST ILLINOIS LATER THIS AFTERNOON. NOT COMPLETELY
SOLD ON ANY WIDESPREAD DEVELOPMENT LATER THIS AFTERNOON AND SO
HAVE REMAINED DRY...BUT IT WOULD NOT BE OUT OF THE QUESTION FOR
SOME ISOLATED SHOWERS ACROSS NORTHEAST ILLINOIS...ESPECIALLY IF
ANY LOW LEVEL CONVERGENCE COULD DEVELOP WHICH THE RAP IS BEGINNING
TO SHOW.
ATTENTION SHIFTS TOWARDS ANOTHER COLD NIGHT TONIGHT AS FORECAST
TEMPS IN THE LOW TO MID 30S ARE FORECAST AS WELL AS A FROST
EXPECTED FOR THE ENTIRE CWA...MINUS THE WARMER METRO AREA. AS THE
LARGE UPPER LEVEL LOW AND ATTENDANT SURFACE LOW/TROUGH EXIT TO THE
EAST TONIGHT...SURFACE RIDGE SETTLES IN. WITH THIS IN PLACE EXPECT
SURFACE WINDS TO RAPIDLY DROP OFF THIS EVENING WITH TEMPS COOLING.
THERE IS SOME CONCERN THAT CLOUD COVER AND THE BEGINNING STAGES OF
WAA COULD AFFECT NIGHT TIME LOWS...BUT STILL FEEL THAT THESE
SHOULD NOT PLAY TOO MUCH OF A ROLE WITH TEMPS FALLING TONIGHT.
CLOUD DEVELOPMENT COULD POSSIBLY HANG ON INTO THE EVENING AT LEAST
TOWARDS 3Z TONIGHT BUT THEN BEGIN TO ERODE AND SHIFT TO THE EAST
TOWARDS MIDNIGHT...WITH ANY HIGH LEVEL CLOUD COVER APPROACHING
FROM THE WEST REMAINING TO THE WEST. ALSO...ALTHOUGH STRONG WAA
WILL BE OCCURRING TO THE WEST OVER IOWA...THIS SHOULD NOT AFFECT
AREAS IN NORTHERN ILLINOIS AND NORTHWEST INDIANA TONIGHT. IN THE
END...SETTING THE STAGE FOR GOOD RADIATIONAL COOLING. SO HAVE
ISSUED A FROST ADVISORY FOR THE ENTIRE CWA...FROM 6Z TONIGHT TO
12Z MONDAY.
TEMPS WILL BEGIN TO RECOVER ON MONDAY AS THE PREVIOUSLY MENTIONED
WAA SHIFTS EAST TOWARDS THE CWA ON MONDAY...WITH TEMPS RISING BACK
INTO THE LOW TO MID 60S. HAVE MAINTAINED CHANCES FOR PRECIP MONDAY
NIGHT INTO EARLY TUESDAY AS THE WAA WING SHOULD SWING SOME
MOISTURE ACROSS PRIMARILY THE NORTHERN HALF OF THE CWA. SHOULD
REMAIN JUST SHOWERS WITH THUNDER NOT EXPECTED AS INSTABILITY IS
APPEARING TO REMAIN TO THE WEST. WITH STRONG WAA STILL OCCURRING
ACROSS THE AREA MONDAY NIGHT INTO TUESDAY...A RATHER WARM DAY IS
APPEARING TO BE LIKELY ON TUESDAY. HAVE RAISED MAX TEMPS FURTHER
FOR TUESDAY AND HAVE HIGHS IN THE MID TO UPPER 80S...AS THERMAL
AXIS WITH 850MB TEMPS NEAR 20C MOVING OVERHEAD. HAVE NOT PUT IN 90
DEGREE TEMPS FOR TUESDAY JUST QUITE YET AS THERE IS STILL SOME
UNCERTAINTY WITH THE EXTENT OF THIS THERMAL AXIS...BUT COULD
EASILY SEE THAT 90 DEGREE WEATHER INCLUDED IN THE FORECAST FOR
TUESDAY AT A LATER TIME. WEDNESDAY LOOKS WARM AGAIN WITH TEMPS
RISING TO THE 80S ONCE AGAIN...BUT WITH CONFIDENCE LOWERING EVEN
FURTHER. GUIDANCE BEGINS TO DIVERGE WITH HANDLING AN APPROACHING
SURFACE LOW AND FRONTAL BOUNDARY. THIS WILL IMPACT HIGHS FOR
WEDNESDAY AS WELL AS PRECIP CHANCES. A SLIGHT CHANCE FOR
THUNDERSTORMS HAS BEEN MAINTAINED DURING THE DAY WEDNESDAY...BUT
IT APPEARS THAT THERE WILL BE BETTER CHANCES FOR THUNDERSTORMS
WEDNESDAY NIGHT. BEYOND THIS POINT FROM THURSDAY INTO
SATURDAY...MODELS BEGIN TO DIVERGE FURTHER. DESPITE THIS MODEL
VARIABILITY...MODELS ARE AGREEING ON A WARMER AND MORE MOIST
AIRMASS REMAINING IN PLACE WITH 850MB DEWPOINTS REALLY INCREASING
ACROSS THE REGION AS WELL AS THE POTENTIAL SETUP FOR LINGERING
BOUNDARIES. THIS WILL HAVE TO BE RESOLVED ONCE GUIDANCE COMES INTO
BETTER AGREEMENT...BUT WITH THE GENERAL PATTERN IS BEGINNING TO
APPEAR MORE ACTIVE WITH PERIODS OF SHOWERS/THUNDERSTORMS POSSIBLE
INTO THE END OF THIS WEEK.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* NORTHWEST WINDS GUSTING TO 18-20KT THIS AFTERNOON.
KREIN
//DISCUSSION...UPDATED 18Z...
A VERY QUIET WEATHER SETUP FOR AVIATION CONCERNS FOR THE PERIOD.
MAIN CONCERN WILL CONTINUE TO BE WIND DIRECTION AS WINDS CONTINUE
TO BE BRISK. HOWEVER...SUSTAINED WINDS AND GUSTS ARE DIMINISHING
THIS AFTERNOON AS HIGH PRESSURE CONTINUES TO BUILD ACROSS THE
MISSISSIPPI VALLEY. ALSO...LATEST SATELITE IMAGERY SHOWER DIURNAL
STRATOCU DEVELOPMENT...WITH A BKN DECK EXPECTED TO DEVELOP EARLY
THIS AFTERNOON...WHICH WILL ALSO HELP LIMIT MIXING. SO...THE
GENERAL TREND FOR WINDS WILL BE TO DECREASE THROUGH THE
AFTERNOON...WHILE BACKING SLIGHTLY TO OUT OF 300 DEGREES. WINDS
WILL THEN GO CALM AND SKIES WILL GO SKC OVERNIGHT.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT AND TUESDAY...VFR.
WEDNESDAY...SLIGHT CHANCE OF SHRA/TSRA.
THURSDAY THROUGH SATURDAY...A PERIOD OR TWO OF SHRA/TSRA POSSIBLE.
IZZI
&&
.MARINE...
255 AM CDT
SOME SHIP OBS AND COASTAL OBS ON EASTERN SHORE SUPPORT MAINTAINING
THE GALE WARNING AS IS THIS MORNING WITH CONTINUED UNSTABLE
CONDITIONS LIKELY TO ALLOW GALES TO LINGER INTO THE MORNING HOURS.
FAR NORTHERN LAKE MICHIGAN COULD SEE GALES LINGER INTO THE EARLY
AFTERNOON DUE TO TIGHTER GRADIENT BUT WINDS ACROSS THE LAKE SHOULD
BE TRENDING DOWNWARD THIS AFTERNOON INTO TONIGHT AS RIDGE AXIS
APPROACHES FROM THE WEST. RIDGE WILL MOVE ACROSS THE LAKE TONIGHT
INTO MONDAY WITH SOUTHERLY WINDS DEVELOPING AND STRENGTHENING AS
SEASONABLY STRONG LOW PRESSURE DEVELOPS OVER THE SOUTHERN CANADIAN
PLAINS TUESDAY. DESPITE FAIRLY TIGHT GRADIENT...SURGE OF VERY WARM
AIR OVER VERY COLD LAKE SHOULD KEEP WINDS AND WAVES SOMEWHAT IN
CHECK TUESDAY INTO WEDNESDAY.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FROST ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...1 AM MONDAY TO 7 AM MONDAY.
IN...FROST ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...1 AM
MONDAY TO 7 AM MONDAY.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 3 PM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 3 PM SUNDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1106 AM CDT SUN MAY 12 2013
.DISCUSSION...
327 AM CDT
MAIN FORECAST CHALLENGES/CONCERNS ARE WITH THE COLD TEMPS AND
FROST TONIGHT WITH A FROST ADVISORY NOW IN PLACE FOR ALL OF THE
CWA TONIGHT...THE ANTICIPATED WARM UP THIS WEEK...AND SIGNS OF A
MORE ACTIVE WEATHER PATTERN BEGINNING TO APPEAR IN THE EXTENDED.
IN THE NEAR TERM...QUIET WEATHER ONGOING ACROSS THE CWA WITH
MOSTLY CLEAR SKIES IN PLACE OVER MUCH OF NORTHEAST ILLINOIS AND
NORTHWEST INDIANA. THE EXCEPTION IS NEAR THE WISCONSIN BORDER
WHERE MID LEVEL CLOUDS ARE TRYING TO SPILL INTO THE AREA THIS
MORNING. THIS IS IN RESPONSE TO SEVERAL WAVES OF ENERGY DROPPING
SOUTHEAST AROUND THE BASE OF THE STRONG UPPER LEVEL LOW TO THE
NORTHEAST. STEEP LOW/MID LEVEL LAPSE RATES STILL IN PLACE EARLY
THIS MORNING WITHIN THIS CYCLONIC WILL CONTINUE TO ALLOW FOR SOME
SCATTERED CLOUD DEVELOPMENT BUT PRIMARILY FOR AREAS IN FAR
NORTHEAST ILLINOIS...AS THIS LOCATION NORTHWARD IS WHERE THE BEST
FORCING/STEEPER LAPSE CURRENTLY RESIDE. ALTHOUGH THERE MAY BE
PERIODS OF THIS SCATTERED MID DECK OR EVEN AN ISOLATED AND BRIEF
CEILING...THINK SKIES SHOULD REMAIN MORE ON THE CLEARER SIDE
THROUGH MID MORNING. TEMPERATURES RIGHT NOW ARE STILL HOLDING
AROUND 40 DEGREES DESPITE THE CLEAR SKIES AND MUCH COLDER AIRMASS
IN PLACE. AS WAS EXPECTED...THE SURFACE LOW TO THE NORTHEAST WITH
TIGHT PRESSURE GRADIENT OVER THE CWA HAS ALLOWED FOR SURFACE WINDS
TO STAY UP NEAR THE 10KT RANGE. SO ONLY EXPECT TEMPS TO FALL A
COUPLE OF MORE DEGREES HERE THIS MORNING BEFORE RISING TO WELL
BELOW NORMAL MAX TEMPS IN THE LOW TO MID 50S TODAY. SHOULD BE A
RATHER QUIET DAY TODAY...ALTHOUGH LOW LEVEL LAPSE RATES REALLY
STEEPEN UP ONCE AGAIN TODAY ACROSS THE CWA. ONCE AGAIN...THESE
LAPSE RATES WITHIN THIS CYCLONIC FLOW WILL PROVIDE FOR SOME
STRATOCU DEVELOPMENT BY MID TO LATE MORNING WITH ANY CLEAR SKIES
BECOMING BROKEN/PARTLY SUNNY. EXPECT THIS TO BE THE CASE THROUGH
THE AFTERNOON AND INTO THE EARLY EVENING. ALTHOUGH CONDITIONS
APPEAR DRY AT THE MOMENT FOR THIS AFTERNOON...LATEST SHORT TERM
GUIDANCE IS TRYING TO INDICATE SOME ISOLATED SHOWER DEVELOPMENT
ACROSS NORTHEAST ILLINOIS LATER THIS AFTERNOON. NOT COMPLETELY
SOLD ON ANY WIDESPREAD DEVELOPMENT LATER THIS AFTERNOON AND SO
HAVE REMAINED DRY...BUT IT WOULD NOT BE OUT OF THE QUESTION FOR
SOME ISOLATED SHOWERS ACROSS NORTHEAST ILLINOIS...ESPECIALLY IF
ANY LOW LEVEL CONVERGENCE COULD DEVELOP WHICH THE RAP IS BEGINNING
TO SHOW.
ATTENTION SHIFTS TOWARDS ANOTHER COLD NIGHT TONIGHT AS FORECAST
TEMPS IN THE LOW TO MID 30S ARE FORECAST AS WELL AS A FROST
EXPECTED FOR THE ENTIRE CWA...MINUS THE WARMER METRO AREA. AS THE
LARGE UPPER LEVEL LOW AND ATTENDANT SURFACE LOW/TROUGH EXIT TO THE
EAST TONIGHT...SURFACE RIDGE SETTLES IN. WITH THIS IN PLACE EXPECT
SURFACE WINDS TO RAPIDLY DROP OFF THIS EVENING WITH TEMPS COOLING.
THERE IS SOME CONCERN THAT CLOUD COVER AND THE BEGINNING STAGES OF
WAA COULD AFFECT NIGHT TIME LOWS...BUT STILL FEEL THAT THESE
SHOULD NOT PLAY TOO MUCH OF A ROLE WITH TEMPS FALLING TONIGHT.
CLOUD DEVELOPMENT COULD POSSIBLY HANG ON INTO THE EVENING AT LEAST
TOWARDS 3Z TONIGHT BUT THEN BEGIN TO ERODE AND SHIFT TO THE EAST
TOWARDS MIDNIGHT...WITH ANY HIGH LEVEL CLOUD COVER APPROACHING
FROM THE WEST REMAINING TO THE WEST. ALSO...ALTHOUGH STRONG WAA
WILL BE OCCURRING TO THE WEST OVER IOWA...THIS SHOULD NOT AFFECT
AREAS IN NORTHERN ILLINOIS AND NORTHWEST INDIANA TONIGHT. IN THE
END...SETTING THE STAGE FOR GOOD RADIATIONAL COOLING. SO HAVE
ISSUED A FROST ADVISORY FOR THE ENTIRE CWA...FROM 6Z TONIGHT TO
12Z MONDAY.
TEMPS WILL BEGIN TO RECOVER ON MONDAY AS THE PREVIOUSLY MENTIONED
WAA SHIFTS EAST TOWARDS THE CWA ON MONDAY...WITH TEMPS RISING BACK
INTO THE LOW TO MID 60S. HAVE MAINTAINED CHANCES FOR PRECIP MONDAY
NIGHT INTO EARLY TUESDAY AS THE WAA WING SHOULD SWING SOME
MOISTURE ACROSS PRIMARILY THE NORTHERN HALF OF THE CWA. SHOULD
REMAIN JUST SHOWERS WITH THUNDER NOT EXPECTED AS INSTABILITY IS
APPEARING TO REMAIN TO THE WEST. WITH STRONG WAA STILL OCCURRING
ACROSS THE AREA MONDAY NIGHT INTO TUESDAY...A RATHER WARM DAY IS
APPEARING TO BE LIKELY ON TUESDAY. HAVE RAISED MAX TEMPS FURTHER
FOR TUESDAY AND HAVE HIGHS IN THE MID TO UPPER 80S...AS THERMAL
AXIS WITH 850MB TEMPS NEAR 20C MOVING OVERHEAD. HAVE NOT PUT IN 90
DEGREE TEMPS FOR TUESDAY JUST QUITE YET AS THERE IS STILL SOME
UNCERTAINTY WITH THE EXTENT OF THIS THERMAL AXIS...BUT COULD
EASILY SEE THAT 90 DEGREE WEATHER INCLUDED IN THE FORECAST FOR
TUESDAY AT A LATER TIME. WEDNESDAY LOOKS WARM AGAIN WITH TEMPS
RISING TO THE 80S ONCE AGAIN...BUT WITH CONFIDENCE LOWERING EVEN
FURTHER. GUIDANCE BEGINS TO DIVERGE WITH HANDLING AN APPROACHING
SURFACE LOW AND FRONTAL BOUNDARY. THIS WILL IMPACT HIGHS FOR
WEDNESDAY AS WELL AS PRECIP CHANCES. A SLIGHT CHANCE FOR
THUNDERSTORMS HAS BEEN MAINTAINED DURING THE DAY WEDNESDAY...BUT
IT APPEARS THAT THERE WILL BE BETTER CHANCES FOR THUNDERSTORMS
WEDNESDAY NIGHT. BEYOND THIS POINT FROM THURSDAY INTO
SATURDAY...MODELS BEGIN TO DIVERGE FURTHER. DESPITE THIS MODEL
VARIABILITY...MODELS ARE AGREEING ON A WARMER AND MORE MOIST
AIRMASS REMAINING IN PLACE WITH 850MB DEWPOINTS REALLY INCREASING
ACROSS THE REGION AS WELL AS THE POTENTIAL SETUP FOR LINGERING
BOUNDARIES. THIS WILL HAVE TO BE RESOLVED ONCE GUIDANCE COMES INTO
BETTER AGREEMENT...BUT WITH THE GENERAL PATTERN IS BEGINNING TO
APPEAR MORE ACTIVE WITH PERIODS OF SHOWERS/THUNDERSTORMS POSSIBLE
INTO THE END OF THIS WEEK.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* NORTHWEST WINDS GUSTING TO 20-25KT TODAY
KREIN
//DISCUSSION...UPDATED 12Z...
WEATHER NOT EXPECTED TO ADVERSELY AFFECT AVIATION OPERATIONS
TODAY. NORTHWEST WINDS WILL ATTAIN SOME GUSTINESS BY MID MORNING
WITH GUSTS FAIRLY STEADY GUSTS OF 20 TO 25KT EXPECTED THROUGH THE
AFTERNOON. WINDS WILL QUICKLY SUBSIDE THIS EVENING. SCT V BKN VFR
DECK OF HIGH BASED STRATOCUMULUS LIKELY TO BLOSSOM THIS MORNING
AND LINGER INTO THE EARLY EVENING BEFORE SKIES GO CLEAR TONIGHT.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT AND TUESDAY...VFR.
WEDNESDAY...SLIGHT CHANCE OF SHRA/TSRA.
THURSDAY THROUGH SATURDAY...A PERIOD OR TWO OF SHRA/TSRA POSSIBLE.
IZZI
&&
.MARINE...
255 AM CDT
SOME SHIP OBS AND COASTAL OBS ON EASTERN SHORE SUPPORT MAINTAINING
THE GALE WARNING AS IS THIS MORNING WITH CONTINUED UNSTABLE
CONDITIONS LIKELY TO ALLOW GALES TO LINGER INTO THE MORNING HOURS.
FAR NORTHERN LAKE MICHIGAN COULD SEE GALES LINGER INTO THE EARLY
AFTERNOON DUE TO TIGHTER GRADIENT BUT WINDS ACROSS THE LAKE SHOULD
BE TRENDING DOWNWARD THIS AFTERNOON INTO TONIGHT AS RIDGE AXIS
APPROACHES FROM THE WEST. RIDGE WILL MOVE ACROSS THE LAKE TONIGHT
INTO MONDAY WITH SOUTHERLY WINDS DEVELOPING AND STRENGTHENING AS
SEASONABLY STRONG LOW PRESSURE DEVELOPS OVER THE SOUTHERN CANADIAN
PLAINS TUESDAY. DESPITE FAIRLY TIGHT GRADIENT...SURGE OF VERY WARM
AIR OVER VERY COLD LAKE SHOULD KEEP WINDS AND WAVES SOMEWHAT IN
CHECK TUESDAY INTO WEDNESDAY.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FROST ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...1 AM MONDAY TO 7 AM MONDAY.
IN...FROST ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...1 AM
MONDAY TO 7 AM MONDAY.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 3 PM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 3 PM SUNDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
910 AM CDT SUN MAY 12 2013
.DISCUSSION...
327 AM CDT
MAIN FORECAST CHALLENGES/CONCERNS ARE WITH THE COLD TEMPS AND
FROST TONIGHT WITH A FROST ADVISORY NOW IN PLACE FOR ALL OF THE
CWA TONIGHT...THE ANTICIPATED WARM UP THIS WEEK...AND SIGNS OF A
MORE ACTIVE WEATHER PATTERN BEGINNING TO APPEAR IN THE EXTENDED.
IN THE NEAR TERM...QUIET WEATHER ONGOING ACROSS THE CWA WITH
MOSTLY CLEAR SKIES IN PLACE OVER MUCH OF NORTHEAST ILLINOIS AND
NORTHWEST INDIANA. THE EXCEPTION IS NEAR THE WISCONSIN BORDER
WHERE MID LEVEL CLOUDS ARE TRYING TO SPILL INTO THE AREA THIS
MORNING. THIS IS IN RESPONSE TO SEVERAL WAVES OF ENERGY DROPPING
SOUTHEAST AROUND THE BASE OF THE STRONG UPPER LEVEL LOW TO THE
NORTHEAST. STEEP LOW/MID LEVEL LAPSE RATES STILL IN PLACE EARLY
THIS MORNING WITHIN THIS CYCLONIC WILL CONTINUE TO ALLOW FOR SOME
SCATTERED CLOUD DEVELOPMENT BUT PRIMARILY FOR AREAS IN FAR
NORTHEAST ILLINOIS...AS THIS LOCATION NORTHWARD IS WHERE THE BEST
FORCING/STEEPER LAPSE CURRENTLY RESIDE. ALTHOUGH THERE MAY BE
PERIODS OF THIS SCATTERED MID DECK OR EVEN AN ISOLATED AND BRIEF
CEILING...THINK SKIES SHOULD REMAIN MORE ON THE CLEARER SIDE
THROUGH MID MORNING. TEMPERATURES RIGHT NOW ARE STILL HOLDING
AROUND 40 DEGREES DESPITE THE CLEAR SKIES AND MUCH COLDER AIRMASS
IN PLACE. AS WAS EXPECTED...THE SURFACE LOW TO THE NORTHEAST WITH
TIGHT PRESSURE GRADIENT OVER THE CWA HAS ALLOWED FOR SURFACE WINDS
TO STAY UP NEAR THE 10KT RANGE. SO ONLY EXPECT TEMPS TO FALL A
COUPLE OF MORE DEGREES HERE THIS MORNING BEFORE RISING TO WELL
BELOW NORMAL MAX TEMPS IN THE LOW TO MID 50S TODAY. SHOULD BE A
RATHER QUIET DAY TODAY...ALTHOUGH LOW LEVEL LAPSE RATES REALLY
STEEPEN UP ONCE AGAIN TODAY ACROSS THE CWA. ONCE AGAIN...THESE
LAPSE RATES WITHIN THIS CYCLONIC FLOW WILL PROVIDE FOR SOME
STRATOCU DEVELOPMENT BY MID TO LATE MORNING WITH ANY CLEAR SKIES
BECOMING BROKEN/PARTLY SUNNY. EXPECT THIS TO BE THE CASE THROUGH
THE AFTERNOON AND INTO THE EARLY EVENING. ALTHOUGH CONDITIONS
APPEAR DRY AT THE MOMENT FOR THIS AFTERNOON...LATEST SHORT TERM
GUIDANCE IS TRYING TO INDICATE SOME ISOLATED SHOWER DEVELOPMENT
ACROSS NORTHEAST ILLINOIS LATER THIS AFTERNOON. NOT COMPLETELY
SOLD ON ANY WIDESPREAD DEVELOPMENT LATER THIS AFTERNOON AND SO
HAVE REMAINED DRY...BUT IT WOULD NOT BE OUT OF THE QUESTION FOR
SOME ISOLATED SHOWERS ACROSS NORTHEAST ILLINOIS...ESPECIALLY IF
ANY LOW LEVEL CONVERGENCE COULD DEVELOP WHICH THE RAP IS BEGINNING
TO SHOW.
ATTENTION SHIFTS TOWARDS ANOTHER COLD NIGHT TONIGHT AS FORECAST
TEMPS IN THE LOW TO MID 30S ARE FORECAST AS WELL AS A FROST
EXPECTED FOR THE ENTIRE CWA...MINUS THE WARMER METRO AREA. AS THE
LARGE UPPER LEVEL LOW AND ATTENDANT SURFACE LOW/TROUGH EXIT TO THE
EAST TONIGHT...SURFACE RIDGE SETTLES IN. WITH THIS IN PLACE EXPECT
SURFACE WINDS TO RAPIDLY DROP OFF THIS EVENING WITH TEMPS COOLING.
THERE IS SOME CONCERN THAT CLOUD COVER AND THE BEGINNING STAGES OF
WAA COULD AFFECT NIGHT TIME LOWS...BUT STILL FEEL THAT THESE
SHOULD NOT PLAY TOO MUCH OF A ROLE WITH TEMPS FALLING TONIGHT.
CLOUD DEVELOPMENT COULD POSSIBLY HANG ON INTO THE EVENING AT LEAST
TOWARDS 3Z TONIGHT BUT THEN BEGIN TO ERODE AND SHIFT TO THE EAST
TOWARDS MIDNIGHT...WITH ANY HIGH LEVEL CLOUD COVER APPROACHING
FROM THE WEST REMAINING TO THE WEST. ALSO...ALTHOUGH STRONG WAA
WILL BE OCCURRING TO THE WEST OVER IOWA...THIS SHOULD NOT AFFECT
AREAS IN NORTHERN ILLINOIS AND NORTHWEST INDIANA TONIGHT. IN THE
END...SETTING THE STAGE FOR GOOD RADIATIONAL COOLING. SO HAVE
ISSUED A FROST ADVISORY FOR THE ENTIRE CWA...FROM 6Z TONIGHT TO
12Z MONDAY.
TEMPS WILL BEGIN TO RECOVER ON MONDAY AS THE PREVIOUSLY MENTIONED
WAA SHIFTS EAST TOWARDS THE CWA ON MONDAY...WITH TEMPS RISING BACK
INTO THE LOW TO MID 60S. HAVE MAINTAINED CHANCES FOR PRECIP MONDAY
NIGHT INTO EARLY TUESDAY AS THE WAA WING SHOULD SWING SOME
MOISTURE ACROSS PRIMARILY THE NORTHERN HALF OF THE CWA. SHOULD
REMAIN JUST SHOWERS WITH THUNDER NOT EXPECTED AS INSTABILITY IS
APPEARING TO REMAIN TO THE WEST. WITH STRONG WAA STILL OCCURRING
ACROSS THE AREA MONDAY NIGHT INTO TUESDAY...A RATHER WARM DAY IS
APPEARING TO BE LIKELY ON TUESDAY. HAVE RAISED MAX TEMPS FURTHER
FOR TUESDAY AND HAVE HIGHS IN THE MID TO UPPER 80S...AS THERMAL
AXIS WITH 850MB TEMPS NEAR 20C MOVING OVERHEAD. HAVE NOT PUT IN 90
DEGREE TEMPS FOR TUESDAY JUST QUITE YET AS THERE IS STILL SOME
UNCERTAINTY WITH THE EXTENT OF THIS THERMAL AXIS...BUT COULD
EASILY SEE THAT 90 DEGREE WEATHER INCLUDED IN THE FORECAST FOR
TUESDAY AT A LATER TIME. WEDNESDAY LOOKS WARM AGAIN WITH TEMPS
RISING TO THE 80S ONCE AGAIN...BUT WITH CONFIDENCE LOWERING EVEN
FURTHER. GUIDANCE BEGINS TO DIVERGE WITH HANDLING AN APPROACHING
SURFACE LOW AND FRONTAL BOUNDARY. THIS WILL IMPACT HIGHS FOR
WEDNESDAY AS WELL AS PRECIP CHANCES. A SLIGHT CHANCE FOR
THUNDERSTORMS HAS BEEN MAINTAINED DURING THE DAY WEDNESDAY...BUT
IT APPEARS THAT THERE WILL BE BETTER CHANCES FOR THUNDERSTORMS
WEDNESDAY NIGHT. BEYOND THIS POINT FROM THURSDAY INTO
SATURDAY...MODELS BEGIN TO DIVERGE FURTHER. DESPITE THIS MODEL
VARIABILITY...MODELS ARE AGREEING ON A WARMER AND MORE MOIST
AIRMASS REMAINING IN PLACE WITH 850MB DEWPOINTS REALLY INCREASING
ACROSS THE REGION AS WELL AS THE POTENTIAL SETUP FOR LINGERING
BOUNDARIES. THIS WILL HAVE TO BE RESOLVED ONCE GUIDANCE COMES INTO
BETTER AGREEMENT...BUT WITH THE GENERAL PATTERN IS BEGINNING TO
APPEAR MORE ACTIVE WITH PERIODS OF SHOWERS/THUNDERSTORMS POSSIBLE
INTO THE END OF THIS WEEK.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* NORTHWEST WINDS GUSTING TO 20-25KT TODAY
KREIN
//DISCUSSION...UPDATED 12Z...
WEATHER NOT EXPECTED TO ADVERSELY AFFECT AVIATION OPERATIONS
TODAY. NORTHWEST WINDS WILL ATTAIN SOME GUSTINESS BY MID MORNING
WITH GUSTS FAIRLY STEADY GUSTS OF 20 TO 25KT EXPECTED THROUGH THE
AFTERNOON. WINDS WILL QUICKLY SUBSIDE THIS EVENING. SCT V BKN VFR
DECK OF HIGH BASED STRATOCUMULUS LIKELY TO BLOSSOM THIS MORNING
AND LINGER INTO THE EARLY EVENING BEFORE SKIES GO CLEAR TONIGHT.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT AND TUESDAY...VFR.
WEDNESDAY...SLIGHT CHANCE OF SHRA/TSRA.
THURSDAY THROUGH SATURDAY...A PERIOD OR TWO OF SHRA/TSRA POSSIBLE.
IZZI
&&
.MARINE...
255 AM CDT
SOME SHIP OBS AND COASTAL OBS ON EASTERN SHORE SUPPORT MAINTAINING
THE GALE WARNING AS IS THIS MORNING WITH CONTINUED UNSTABLE
CONDITIONS LIKELY TO ALLOW GALES TO LINGER INTO THE MORNING HOURS.
FAR NORTHERN LAKE MICHIGAN COULD SEE GALES LINGER INTO THE EARLY
AFTERNOON DUE TO TIGHTER GRADIENT BUT WINDS ACROSS THE LAKE SHOULD
BE TRENDING DOWNWARD THIS AFTERNOON INTO TONIGHT AS RIDGE AXIS
APPROACHES FROM THE WEST. RIDGE WILL MOVE ACROSS THE LAKE TONIGHT
INTO MONDAY WITH SOUTHERLY WINDS DEVELOPING AND STRENGTHENING AS
SEASONABLY STRONG LOW PRESSURE DEVELOPS OVER THE SOUTHERN CANADIAN
PLAINS TUESDAY. DESPITE FAIRLY TIGHT GRADIENT...SURGE OF VERY WARM
AIR OVER VERY COLD LAKE SHOULD KEEP WINDS AND WAVES SOMEWHAT IN
CHECK TUESDAY INTO WEDNESDAY.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FROST ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...1 AM MONDAY TO 7 AM MONDAY.
IN...FROST ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...1 AM
MONDAY TO 7 AM MONDAY.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 3 PM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 3 PM SUNDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
600 AM CDT SUN MAY 12 2013
.DISCUSSION...
327 AM CDT
MAIN FORECAST CHALLENGES/CONCERNS ARE WITH THE COLD TEMPS AND
FROST TONIGHT WITH A FROST ADVISORY NOW IN PLACE FOR ALL OF THE
CWA TONIGHT...THE ANTICIPATED WARM UP THIS WEEK...AND SIGNS OF A
MORE ACTIVE WEATHER PATTERN BEGINNING TO APPEAR IN THE EXTENDED.
IN THE NEAR TERM...QUIET WEATHER ONGOING ACROSS THE CWA WITH
MOSTLY CLEAR SKIES IN PLACE OVER MUCH OF NORTHEAST ILLINOIS AND
NORTHWEST INDIANA. THE EXCEPTION IS NEAR THE WISCONSIN BORDER
WHERE MID LEVEL CLOUDS ARE TRYING TO SPILL INTO THE AREA THIS
MORNING. THIS IS IN RESPONSE TO SEVERAL WAVES OF ENERGY DROPPING
SOUTHEAST AROUND THE BASE OF THE STRONG UPPER LEVEL LOW TO THE
NORTHEAST. STEEP LOW/MID LEVEL LAPSE RATES STILL IN PLACE EARLY
THIS MORNING WITHIN THIS CYCLONIC WILL CONTINUE TO ALLOW FOR SOME
SCATTERED CLOUD DEVELOPMENT BUT PRIMARILY FOR AREAS IN FAR
NORTHEAST ILLINOIS...AS THIS LOCATION NORTHWARD IS WHERE THE BEST
FORCING/STEEPER LAPSE CURRENTLY RESIDE. ALTHOUGH THERE MAY BE
PERIODS OF THIS SCATTERED MID DECK OR EVEN AN ISOLATED AND BRIEF
CEILING...THINK SKIES SHOULD REMAIN MORE ON THE CLEARER SIDE
THROUGH MID MORNING. TEMPERATURES RIGHT NOW ARE STILL HOLDING
AROUND 40 DEGREES DESPITE THE CLEAR SKIES AND MUCH COLDER AIRMASS
IN PLACE. AS WAS EXPECTED...THE SURFACE LOW TO THE NORTHEAST WITH
TIGHT PRESSURE GRADIENT OVER THE CWA HAS ALLOWED FOR SURFACE WINDS
TO STAY UP NEAR THE 10KT RANGE. SO ONLY EXPECT TEMPS TO FALL A
COUPLE OF MORE DEGREES HERE THIS MORNING BEFORE RISING TO WELL
BELOW NORMAL MAX TEMPS IN THE LOW TO MID 50S TODAY. SHOULD BE A
RATHER QUIET DAY TODAY...ALTHOUGH LOW LEVEL LAPSE RATES REALLY
STEEPEN UP ONCE AGAIN TODAY ACROSS THE CWA. ONCE AGAIN...THESE
LAPSE RATES WITHIN THIS CYCLONIC FLOW WILL PROVIDE FOR SOME
STRATOCU DEVELOPMENT BY MID TO LATE MORNING WITH ANY CLEAR SKIES
BECOMING BROKEN/PARTLY SUNNY. EXPECT THIS TO BE THE CASE THROUGH
THE AFTERNOON AND INTO THE EARLY EVENING. ALTHOUGH CONDITIONS
APPEAR DRY AT THE MOMENT FOR THIS AFTERNOON...LATEST SHORT TERM
GUIDANCE IS TRYING TO INDICATE SOME ISOLATED SHOWER DEVELOPMENT
ACROSS NORTHEAST ILLINOIS LATER THIS AFTERNOON. NOT COMPLETELY
SOLD ON ANY WIDESPREAD DEVELOPMENT LATER THIS AFTERNOON AND SO
HAVE REMAINED DRY...BUT IT WOULD NOT BE OUT OF THE QUESTION FOR
SOME ISOLATED SHOWERS ACROSS NORTHEAST ILLINOIS...ESPECIALLY IF
ANY LOW LEVEL CONVERGENCE COULD DEVELOP WHICH THE RAP IS BEGINNING
TO SHOW.
ATTENTION SHIFTS TOWARDS ANOTHER COLD NIGHT TONIGHT AS FORECAST
TEMPS IN THE LOW TO MID 30S ARE FORECAST AS WELL AS A FROST
EXPECTED FOR THE ENTIRE CWA...MINUS THE WARMER METRO AREA. AS THE
LARGE UPPER LEVEL LOW AND ATTENDANT SURFACE LOW/TROUGH EXIT TO THE
EAST TONIGHT...SURFACE RIDGE SETTLES IN. WITH THIS IN PLACE EXPECT
SURFACE WINDS TO RAPIDLY DROP OFF THIS EVENING WITH TEMPS COOLING.
THERE IS SOME CONCERN THAT CLOUD COVER AND THE BEGINNING STAGES OF
WAA COULD AFFECT NIGHT TIME LOWS...BUT STILL FEEL THAT THESE
SHOULD NOT PLAY TOO MUCH OF A ROLE WITH TEMPS FALLING TONIGHT.
CLOUD DEVELOPMENT COULD POSSIBLY HANG ON INTO THE EVENING AT LEAST
TOWARDS 3Z TONIGHT BUT THEN BEGIN TO ERODE AND SHIFT TO THE EAST
TOWARDS MIDNIGHT...WITH ANY HIGH LEVEL CLOUD COVER APPROACHING
FROM THE WEST REMAINING TO THE WEST. ALSO...ALTHOUGH STRONG WAA
WILL BE OCCURRING TO THE WEST OVER IOWA...THIS SHOULD NOT AFFECT
AREAS IN NORTHERN ILLINOIS AND NORTHWEST INDIANA TONIGHT. IN THE
END...SETTING THE STAGE FOR GOOD RADIATIONAL COOLING. SO HAVE
ISSUED A FROST ADVISORY FOR THE ENTIRE CWA...FROM 6Z TONIGHT TO
12Z MONDAY.
TEMPS WILL BEGIN TO RECOVER ON MONDAY AS THE PREVIOUSLY MENTIONED
WAA SHIFTS EAST TOWARDS THE CWA ON MONDAY...WITH TEMPS RISING BACK
INTO THE LOW TO MID 60S. HAVE MAINTAINED CHANCES FOR PRECIP MONDAY
NIGHT INTO EARLY TUESDAY AS THE WAA WING SHOULD SWING SOME
MOISTURE ACROSS PRIMARILY THE NORTHERN HALF OF THE CWA. SHOULD
REMAIN JUST SHOWERS WITH THUNDER NOT EXPECTED AS INSTABILITY IS
APPEARING TO REMAIN TO THE WEST. WITH STRONG WAA STILL OCCURRING
ACROSS THE AREA MONDAY NIGHT INTO TUESDAY...A RATHER WARM DAY IS
APPEARING TO BE LIKELY ON TUESDAY. HAVE RAISED MAX TEMPS FURTHER
FOR TUESDAY AND HAVE HIGHS IN THE MID TO UPPER 80S...AS THERMAL
AXIS WITH 850MB TEMPS NEAR 20C MOVING OVERHEAD. HAVE NOT PUT IN 90
DEGREE TEMPS FOR TUESDAY JUST QUITE YET AS THERE IS STILL SOME
UNCERTAINTY WITH THE EXTENT OF THIS THERMAL AXIS...BUT COULD
EASILY SEE THAT 90 DEGREE WEATHER INCLUDED IN THE FORECAST FOR
TUESDAY AT A LATER TIME. WEDNESDAY LOOKS WARM AGAIN WITH TEMPS
RISING TO THE 80S ONCE AGAIN...BUT WITH CONFIDENCE LOWERING EVEN
FURTHER. GUIDANCE BEGINS TO DIVERGE WITH HANDLING AN APPROACHING
SURFACE LOW AND FRONTAL BOUNDARY. THIS WILL IMPACT HIGHS FOR
WEDNESDAY AS WELL AS PRECIP CHANCES. A SLIGHT CHANCE FOR
THUNDERSTORMS HAS BEEN MAINTAINED DURING THE DAY WEDNESDAY...BUT
IT APPEARS THAT THERE WILL BE BETTER CHANCES FOR THUNDERSTORMS
WEDNESDAY NIGHT. BEYOND THIS POINT FROM THURSDAY INTO
SATURDAY...MODELS BEGIN TO DIVERGE FURTHER. DESPITE THIS MODEL
VARIABILITY...MODELS ARE AGREEING ON A WARMER AND MORE MOIST
AIRMASS REMAINING IN PLACE WITH 850MB DEWPOINTS REALLY INCREASING
ACROSS THE REGION AS WELL AS THE POTENTIAL SETUP FOR LINGERING
BOUNDARIES. THIS WILL HAVE TO BE RESOLVED ONCE GUIDANCE COMES INTO
BETTER AGREEMENT...BUT WITH THE GENERAL PATTERN IS BEGINNING TO
APPEAR MORE ACTIVE WITH PERIODS OF SHOWERS/THUNDERSTORMS POSSIBLE
INTO THE END OF THIS WEEK.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* NORTHWEST WINDS GUSTING TO 20-25KT TODAY
IZZI
//DISCUSSION...UPDATED 12Z...
WEATHER NOT EXPECTED TO ADVERSELY AFFECT AVIATION OPERATIONS
TODAY. NORTHWEST WINDS WILL ATTAIN SOME GUSTINESS BY MID MORNING
WITH GUSTS FAIRLY STEADY GUSTS OF 20 TO 25KT EXPECTED THROUGH THE
AFTERNOON. WINDS WILL QUICKLY SUBSIDE THIS EVENING. SCT V BKN VFR
DECK OF HIGH BASED STRATOCUMULUS LIKELY TO BLOSSOM THIS MORNING
AND LINGER INTO THE EARLY EVENING BEFORE SKIES GO CLEAR TONIGHT.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT AND TUESDAY...VFR.
WEDNESDAY...SLIGHT CHANCE OF SHRA/TSRA.
THURSDAY THROUGH SATURDAY...A PERIOD OR TWO OF SHRA/TSRA POSSIBLE.
IZZI
&&
.MARINE...
255 AM CDT
SOME SHIP OBS AND COASTAL OBS ON EASTERN SHORE SUPPORT MAINTAINING
THE GALE WARNING AS IS THIS MORNING WITH CONTINUED UNSTABLE
CONDITIONS LIKELY TO ALLOW GALES TO LINGER INTO THE MORNING HOURS.
FAR NORTHERN LAKE MICHIGAN COULD SEE GALES LINGER INTO THE EARLY
AFTERNOON DUE TO TIGHTER GRADIENT BUT WINDS ACROSS THE LAKE SHOULD
BE TRENDING DOWNWARD THIS AFTERNOON INTO TONIGHT AS RIDGE AXIS
APPROACHES FROM THE WEST. RIDGE WILL MOVE ACROSS THE LAKE TONIGHT
INTO MONDAY WITH SOUTHERLY WINDS DEVELOPING AND STRENGTHENING AS
SEASONABLY STRONG LOW PRESSURE DEVELOPS OVER THE SOUTHERN CANADIAN
PLAINS TUESDAY. DESPITE FAIRLY TIGHT GRADIENT...SURGE OF VERY WARM
AIR OVER VERY COLD LAKE SHOULD KEEP WINDS AND WAVES SOMEWHAT IN
CHECK TUESDAY INTO WEDNESDAY.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FROST ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...1 AM MONDAY TO 7 AM MONDAY.
IN...FROST ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...1 AM
MONDAY TO 7 AM MONDAY.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 3 PM SUNDAY.
GALE WARNING...LMZ366-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ868-
LMZ870-LMZ872-LMZ874 UNTIL 9 AM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 3 PM SUNDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
405 AM CDT SUN MAY 12 2013
.DISCUSSION...
327 AM CDT
MAIN FORECAST CHALLENGES/CONCERNS ARE WITH THE COLD TEMPS AND
FROST TONIGHT WITH A FROST ADVISORY NOW IN PLACE FOR ALL OF THE
CWA TONIGHT...THE ANTICIPATED WARM UP THIS WEEK...AND SIGNS OF A
MORE ACTIVE WEATHER PATTERN BEGINNING TO APPEAR IN THE EXTENDED.
IN THE NEAR TERM...QUIET WEATHER ONGOING ACROSS THE CWA WITH
MOSTLY CLEAR SKIES IN PLACE OVER MUCH OF NORTHEAST ILLINOIS AND
NORTHWEST INDIANA. THE EXCEPTION IS NEAR THE WISCONSIN BORDER
WHERE MID LEVEL CLOUDS ARE TRYING TO SPILL INTO THE AREA THIS
MORNING. THIS IS IN RESPONSE TO SEVERAL WAVES OF ENERGY DROPPING
SOUTHEAST AROUND THE BASE OF THE STRONG UPPER LEVEL LOW TO THE
NORTHEAST. STEEP LOW/MID LEVEL LAPSE RATES STILL IN PLACE EARLY
THIS MORNING WITHIN THIS CYCLONIC WILL CONTINUE TO ALLOW FOR SOME
SCATTERED CLOUD DEVELOPMENT BUT PRIMARILY FOR AREAS IN FAR
NORTHEAST ILLINOIS...AS THIS LOCATION NORTHWARD IS WHERE THE BEST
FORCING/STEEPER LAPSE CURRENTLY RESIDE. ALTHOUGH THERE MAY BE
PERIODS OF THIS SCATTERED MID DECK OR EVEN AN ISOLATED AND BRIEF
CEILING...THINK SKIES SHOULD REMAIN MORE ON THE CLEARER SIDE
THROUGH MID MORNING. TEMPERATURES RIGHT NOW ARE STILL HOLDING
AROUND 40 DEGREES DESPITE THE CLEAR SKIES AND MUCH COLDER AIRMASS
IN PLACE. AS WAS EXPECTED...THE SURFACE LOW TO THE NORTHEAST WITH
TIGHT PRESSURE GRADIENT OVER THE CWA HAS ALLOWED FOR SURFACE WINDS
TO STAY UP NEAR THE 10KT RANGE. SO ONLY EXPECT TEMPS TO FALL A
COUPLE OF MORE DEGREES HERE THIS MORNING BEFORE RISING TO WELL
BELOW NORMAL MAX TEMPS IN THE LOW TO MID 50S TODAY. SHOULD BE A
RATHER QUIET DAY TODAY...ALTHOUGH LOW LEVEL LAPSE RATES REALLY
STEEPEN UP ONCE AGAIN TODAY ACROSS THE CWA. ONCE AGAIN...THESE
LAPSE RATES WITHIN THIS CYCLONIC FLOW WILL PROVIDE FOR SOME
STRATOCU DEVELOPMENT BY MID TO LATE MORNING WITH ANY CLEAR SKIES
BECOMING BROKEN/PARTLY SUNNY. EXPECT THIS TO BE THE CASE THROUGH
THE AFTERNOON AND INTO THE EARLY EVENING. ALTHOUGH CONDITIONS
APPEAR DRY AT THE MOMENT FOR THIS AFTERNOON...LATEST SHORT TERM
GUIDANCE IS TRYING TO INDICATE SOME ISOLATED SHOWER DEVELOPMENT
ACROSS NORTHEAST ILLINOIS LATER THIS AFTERNOON. NOT COMPLETELY
SOLD ON ANY WIDESPREAD DEVELOPMENT LATER THIS AFTERNOON AND SO
HAVE REMAINED DRY...BUT IT WOULD NOT BE OUT OF THE QUESTION FOR
SOME ISOLATED SHOWERS ACROSS NORTHEAST ILLINOIS...ESPECIALLY IF
ANY LOW LEVEL CONVERGENCE COULD DEVELOP WHICH THE RAP IS BEGINNING
TO SHOW.
ATTENTION SHIFTS TOWARDS ANOTHER COLD NIGHT TONIGHT AS FORECAST
TEMPS IN THE LOW TO MID 30S ARE FORECAST AS WELL AS A FROST
EXPECTED FOR THE ENTIRE CWA...MINUS THE WARMER METRO AREA. AS THE
LARGE UPPER LEVEL LOW AND ATTENDANT SURFACE LOW/TROUGH EXIT TO THE
EAST TONIGHT...SURFACE RIDGE SETTLES IN. WITH THIS IN PLACE EXPECT
SURFACE WINDS TO RAPIDLY DROP OFF THIS EVENING WITH TEMPS COOLING.
THERE IS SOME CONCERN THAT CLOUD COVER AND THE BEGINNING STAGES OF
WAA COULD AFFECT NIGHT TIME LOWS...BUT STILL FEEL THAT THESE
SHOULD NOT PLAY TOO MUCH OF A ROLE WITH TEMPS FALLING TONIGHT.
CLOUD DEVELOPMENT COULD POSSIBLY HANG ON INTO THE EVENING AT LEAST
TOWARDS 3Z TONIGHT BUT THEN BEGIN TO ERODE AND SHIFT TO THE EAST
TOWARDS MIDNIGHT...WITH ANY HIGH LEVEL CLOUD COVER APPROACHING
FROM THE WEST REMAINING TO THE WEST. ALSO...ALTHOUGH STRONG WAA
WILL BE OCCURRING TO THE WEST OVER IOWA...THIS SHOULD NOT AFFECT
AREAS IN NORTHERN ILLINOIS AND NORTHWEST INDIANA TONIGHT. IN THE
END...SETTING THE STAGE FOR GOOD RADIATIONAL COOLING. SO HAVE
ISSUED A FROST ADVISORY FOR THE ENTIRE CWA...FROM 6Z TONIGHT TO
12Z MONDAY.
TEMPS WILL BEGIN TO RECOVER ON MONDAY AS THE PREVIOUSLY MENTIONED
WAA SHIFTS EAST TOWARDS THE CWA ON MONDAY...WITH TEMPS RISING BACK
INTO THE LOW TO MID 60S. HAVE MAINTAINED CHANCES FOR PRECIP MONDAY
NIGHT INTO EARLY TUESDAY AS THE WAA WING SHOULD SWING SOME
MOISTURE ACROSS PRIMARILY THE NORTHERN HALF OF THE CWA. SHOULD
REMAIN JUST SHOWERS WITH THUNDER NOT EXPECTED AS INSTABILITY IS
APPEARING TO REMAIN TO THE WEST. WITH STRONG WAA STILL OCCURRING
ACROSS THE AREA MONDAY NIGHT INTO TUESDAY...A RATHER WARM DAY IS
APPEARING TO BE LIKELY ON TUESDAY. HAVE RAISED MAX TEMPS FURTHER
FOR TUESDAY AND HAVE HIGHS IN THE MID TO UPPER 80S...AS THERMAL
AXIS WITH 850MB TEMPS NEAR 20C MOVING OVERHEAD. HAVE NOT PUT IN 90
DEGREE TEMPS FOR TUESDAY JUST QUITE YET AS THERE IS STILL SOME
UNCERTAINTY WITH THE EXTENT OF THIS THERMAL AXIS...BUT COULD
EASILY SEE THAT 90 DEGREE WEATHER INCLUDED IN THE FORECAST FOR
TUESDAY AT A LATER TIME. WEDNESDAY LOOKS WARM AGAIN WITH TEMPS
RISING TO THE 80S ONCE AGAIN...BUT WITH CONFIDENCE LOWERING EVEN
FURTHER. GUIDANCE BEGINS TO DIVERGE WITH HANDLING AN APPROACHING
SURFACE LOW AND FRONTAL BOUNDARY. THIS WILL IMPACT HIGHS FOR
WEDNESDAY AS WELL AS PRECIP CHANCES. A SLIGHT CHANCE FOR
THUNDERSTORMS HAS BEEN MAINTAINED DURING THE DAY WEDNESDAY...BUT
IT APPEARS THAT THERE WILL BE BETTER CHANCES FOR THUNDERSTORMS
WEDNESDAY NIGHT. BEYOND THIS POINT FROM THURSDAY INTO
SATURDAY...MODELS BEGIN TO DIVERGE FURTHER. DESPITE THIS MODEL
VARIABILITY...MODELS ARE AGREEING ON A WARMER AND MORE MOIST
AIRMASS REMAINING IN PLACE WITH 850MB DEWPOINTS REALLY INCREASING
ACROSS THE REGION AS WELL AS THE POTENTIAL SETUP FOR LINGERING
BOUNDARIES. THIS WILL HAVE TO BE RESOLVED ONCE GUIDANCE COMES INTO
BETTER AGREEMENT...BUT WITH THE GENERAL PATTERN IS BEGINNING TO
APPEAR MORE ACTIVE WITH PERIODS OF SHOWERS/THUNDERSTORMS POSSIBLE
INTO THE END OF THIS WEEK.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* NORTHWEST WINDS BECOME A BIT GUSTY SUNDAY
IZZI
//DISCUSSION...UPDATED 06Z...
DEEP TROUGH WILL CONTINUE TO INFLUENCE THE REGION THIS TAF CYCLE
WITH COLD AIR ALOFT RESULTING IN PERIODIC SCT V BKN VFR
CIGS...PARTICULARLY DURING PEAK HEATING SUNDAY. NORTHWEST WINDS
WILL BECOME GUSTY AGAIN SUNDAY MORNING INTO THE AFTERNOON...THOUGH
LIGHTER THAN ON SATURDAY WITH PEAK GUSTS GENERALLY IN THE 20-25KT
RANGE. SKIES WILL CLEAR OUT AND WINDS GO CALM SUNDAY EVENING.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...SLT CHC OF SHRA DURING THE NIGHT.
TUESDAY...VFR. GUSTY SSW WINDS.
WEDNESDAY...SLT CHC OF TSRA.
THURSDAY-FRIDAY...CHC OF TSRA.
MTF
&&
.MARINE...
255 AM CDT
SOME SHIP OBS AND COASTAL OBS ON EASTERN SHORE SUPPORT MAINTAINING
THE GALE WARNING AS IS THIS MORNING WITH CONTINUED UNSTABLE
CONDITIONS LIKELY TO ALLOW GALES TO LINGER INTO THE MORNING HOURS.
FAR NORTHERN LAKE MICHIGAN COULD SEE GALES LINGER INTO THE EARLY
AFTERNOON DUE TO TIGHTER GRADIENT BUT WINDS ACROSS THE LAKE SHOULD
BE TRENDING DOWNWARD THIS AFTERNOON INTO TONIGHT AS RIDGE AXIS
APPROACHES FROM THE WEST. RIDGE WILL MOVE ACROSS THE LAKE TONIGHT
INTO MONDAY WITH SOUTHERLY WINDS DEVELOPING AND STRENGTHENING AS
SEASONABLY STRONG LOW PRESSURE DEVELOPS OVER THE SOUTHERN CANADIAN
PLAINS TUESDAY. DESPITE FAIRLY TIGHT GRADIENT...SURGE OF VERY WARM
AIR OVER VERY COLD LAKE SHOULD KEEP WINDS AND WAVES SOMEWHAT IN
CHECK TUESDAY INTO WEDNESDAY.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FROST ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...1 AM MONDAY TO 7 AM MONDAY.
IN...FROST ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...1 AM
MONDAY TO 7 AM MONDAY.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 3 PM SUNDAY.
GALE WARNING...LMZ366-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ868-
LMZ870-LMZ872-LMZ874 UNTIL 9 AM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 3 PM SUNDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
333 AM CDT SUN MAY 12 2013
.DISCUSSION...
327 AM CDT
MAIN FORECAST CHALLENGES/CONCERNS ARE WITH THE COLD TEMPS AND
FROST TONIGHT WITH A FROST ADVISORY NOW IN PLACE FOR ALL OF THE
CWA TONIGHT...THE ANTICIPATED WARM UP THIS WEEK...AND SIGNS OF A
MORE ACTIVE WEATHER PATTERN BEGINNING TO APPEAR IN THE EXTENDED.
IN THE NEAR TERM...QUIET WEATHER ONGOING ACROSS THE CWA WITH
MOSTLY CLEAR SKIES IN PLACE OVER MUCH OF NORTHEAST ILLINOIS AND
NORTHWEST INDIANA. THE EXCEPTION IS NEAR THE WISCONSIN BORDER
WHERE MID LEVEL CLOUDS ARE TRYING TO SPILL INTO THE AREA THIS
MORNING. THIS IS IN RESPONSE TO SEVERAL WAVES OF ENERGY DROPPING
SOUTHEAST AROUND THE BASE OF THE STRONG UPPER LEVEL LOW TO THE
NORTHEAST. STEEP LOW/MID LEVEL LAPSE RATES STILL IN PLACE EARLY
THIS MORNING WITHIN THIS CYCLONIC WILL CONTINUE TO ALLOW FOR SOME
SCATTERED CLOUD DEVELOPMENT BUT PRIMARILY FOR AREAS IN FAR
NORTHEAST ILLINOIS...AS THIS LOCATION NORTHWARD IS WHERE THE BEST
FORCING/STEEPER LAPSE CURRENTLY RESIDE. ALTHOUGH THERE MAY BE
PERIODS OF THIS SCATTERED MID DECK OR EVEN AN ISOLATED AND BRIEF
CEILING...THINK SKIES SHOULD REMAIN MORE ON THE CLEARER SIDE
THROUGH MID MORNING. TEMPERATURES RIGHT NOW ARE STILL HOLDING
AROUND 40 DEGREES DESPITE THE CLEAR SKIES AND MUCH COLDER AIRMASS
IN PLACE. AS WAS EXPECTED...THE SURFACE LOW TO THE NORTHEAST WITH
TIGHT PRESSURE GRADIENT OVER THE CWA HAS ALLOWED FOR SURFACE WINDS
TO STAY UP NEAR THE 10KT RANGE. SO ONLY EXPECT TEMPS TO FALL A
COUPLE OF MORE DEGREES HERE THIS MORNING BEFORE RISING TO WELL
BELOW NORMAL MAX TEMPS IN THE LOW TO MID 50S TODAY. SHOULD BE A
RATHER QUIET DAY TODAY...ALTHOUGH LOW LEVEL LAPSE RATES REALLY
STEEPEN UP ONCE AGAIN TODAY ACROSS THE CWA. ONCE AGAIN...THESE
LAPSE RATES WITHIN THIS CYCLONIC FLOW WILL PROVIDE FOR SOME
STRATOCU DEVELOPMENT BY MID TO LATE MORNING WITH ANY CLEAR SKIES
BECOMING BROKEN/PARTLY SUNNY. EXPECT THIS TO BE THE CASE THROUGH
THE AFTERNOON AND INTO THE EARLY EVENING. ALTHOUGH CONDITIONS
APPEAR DRY AT THE MOMENT FOR THIS AFTERNOON...LATEST SHORT TERM
GUIDANCE IS TRYING TO INDICATE SOME ISOLATED SHOWER DEVELOPMENT
ACROSS NORTHEAST ILLINOIS LATER THIS AFTERNOON. NOT COMPLETELY
SOLD ON ANY WIDESPREAD DEVELOPMENT LATER THIS AFTERNOON AND SO
HAVE REMAINED DRY...BUT IT WOULD NOT BE OUT OF THE QUESTION FOR
SOME ISOLATED SHOWERS ACROSS NORTHEAST ILLINOIS...ESPECIALLY IF
ANY LOW LEVEL CONVERGENCE COULD DEVELOP WHICH THE RAP IS BEGINNING
TO SHOW.
ATTENTION SHIFTS TOWARDS ANOTHER COLD NIGHT TONIGHT AS FORECAST
TEMPS IN THE LOW TO MID 30S ARE FORECAST AS WELL AS A FROST
EXPECTED FOR THE ENTIRE CWA...MINUS THE WARMER METRO AREA. AS THE
LARGE UPPER LEVEL LOW AND ATTENDANT SURFACE LOW/TROUGH EXIT TO THE
EAST TONIGHT...SURFACE RIDGE SETTLES IN. WITH THIS IN PLACE EXPECT
SURFACE WINDS TO RAPIDLY DROP OFF THIS EVENING WITH TEMPS COOLING.
THERE IS SOME CONCERN THAT CLOUD COVER AND THE BEGINNING STAGES OF
WAA COULD AFFECT NIGHT TIME LOWS...BUT STILL FEEL THAT THESE
SHOULD NOT PLAY TOO MUCH OF A ROLE WITH TEMPS FALLING TONIGHT.
CLOUD DEVELOPMENT COULD POSSIBLY HANG ON INTO THE EVENING AT LEAST
TOWARDS 3Z TONIGHT BUT THEN BEGIN TO ERODE AND SHIFT TO THE EAST
TOWARDS MIDNIGHT...WITH ANY HIGH LEVEL CLOUD COVER APPROACHING
FROM THE WEST REMAINING TO THE WEST. ALSO...ALTHOUGH STRONG WAA
WILL BE OCCURRING TO THE WEST OVER IOWA...THIS SHOULD NOT AFFECT
AREAS IN NORTHERN ILLINOIS AND NORTHWEST INDIANA TONIGHT. IN THE
END...SETTING THE STAGE FOR GOOD RADIATIONAL COOLING. SO HAVE
ISSUED A FROST ADVISORY FOR THE ENTIRE CWA...FROM 6Z TONIGHT TO
12Z MONDAY.
TEMPS WILL BEGIN TO RECOVER ON MONDAY AS THE PREVIOUSLY MENTIONED
WAA SHIFTS EAST TOWARDS THE CWA ON MONDAY...WITH TEMPS RISING BACK
INTO THE LOW TO MID 60S. HAVE MAINTAINED CHANCES FOR PRECIP MONDAY
NIGHT INTO EARLY TUESDAY AS THE WAA WING SHOULD SWING SOME
MOISTURE ACROSS PRIMARILY THE NORTHERN HALF OF THE CWA. SHOULD
REMAIN JUST SHOWERS WITH THUNDER NOT EXPECTED AS INSTABILITY IS
APPEARING TO REMAIN TO THE WEST. WITH STRONG WAA STILL OCCURRING
ACROSS THE AREA MONDAY NIGHT INTO TUESDAY...A RATHER WARM DAY IS
APPEARING TO BE LIKELY ON TUESDAY. HAVE RAISED MAX TEMPS FURTHER
FOR TUESDAY AND HAVE HIGHS IN THE MID TO UPPER 80S...AS THERMAL
AXIS WITH 850MB TEMPS NEAR 20C MOVING OVERHEAD. HAVE NOT PUT IN 90
DEGREE TEMPS FOR TUESDAY JUST QUITE YET AS THERE IS STILL SOME
UNCERTAINTY WITH THE EXTENT OF THIS THERMAL AXIS...BUT COULD
EASILY SEE THAT 90 DEGREE WEATHER INCLUDED IN THE FORECAST FOR
TUESDAY AT A LATER TIME. WEDNESDAY LOOKS WARM AGAIN WITH TEMPS
RISING TO THE 80S ONCE AGAIN...BUT WITH CONFIDENCE LOWERING EVEN
FURTHER. GUIDANCE BEGINS TO DIVERGE WITH HANDLING AN APPROACHING
SURFACE LOW AND FRONTAL BOUNDARY. THIS WILL IMPACT HIGHS FOR
WEDNESDAY AS WELL AS PRECIP CHANCES. A SLIGHT CHANCE FOR
THUNDERSTORMS HAS BEEN MAINTAINED DURING THE DAY WEDNESDAY...BUT
IT APPEARS THAT THERE WILL BE BETTER CHANCES FOR THUNDERSTORMS
WEDNESDAY NIGHT. BEYOND THIS POINT FROM THURSDAY INTO
SATURDAY...MODELS BEGIN TO DIVERGE FURTHER. DESPITE THIS MODEL
VARIABILITY...MODELS ARE AGREEING ON A WARMER AND MORE MOIST
AIRMASS REMAINING IN PLACE WITH 850MB DEWPOINTS REALLY INCREASING
ACROSS THE REGION AS WELL AS THE POTENTIAL SETUP FOR LINGERING
BOUNDARIES. THIS WILL HAVE TO BE RESOLVED ONCE GUIDANCE COMES INTO
BETTER AGREEMENT...BUT WITH THE GENERAL PATTERN IS BEGINNING TO
APPEAR MORE ACTIVE WITH PERIODS OF SHOWERS/THUNDERSTORMS POSSIBLE
INTO THE END OF THIS WEEK.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* NORTHWEST WINDS BECOME A BIT GUSTY SUNDAY
IZZI
//DISCUSSION...UPDATED 06Z...
DEEP TROUGH WILL CONTINUE TO INFLUENCE THE REGION THIS TAF CYCLE
WITH COLD AIR ALOFT RESULTING IN PERIODIC SCT V BKN VFR
CIGS...PARTICULARLY DURING PEAK HEATING SUNDAY. NORTHWEST WINDS
WILL BECOME GUSTY AGAIN SUNDAY MORNING INTO THE AFTERNOON...THOUGH
LIGHTER THAN ON SATURDAY WITH PEAK GUSTS GENERALLY IN THE 20-25KT
RANGE. SKIES WILL CLEAR OUT AND WINDS GO CALM SUNDAY EVENING.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...SLT CHC OF SHRA DURING THE NIGHT.
TUESDAY...VFR. GUSTY SSW WINDS.
WEDNESDAY...SLT CHC OF TSRA.
THURSDAY-FRIDAY...CHC OF TSRA.
MTF
&&
.MARINE...
255 AM CDT
SOME SHIP OBS AND COASTAL OBS ON EASTERN SHORE SUPPORT MAINTAINING
THE GALE WARNING AS IS THIS MORNING WITH CONTINUED UNSTABLE
CONDITIONS LIKELY TO ALLOW GALES TO LINGER INTO THE MORNING HOURS.
FAR NORTHERN LAKE MICHIGAN COULD SEE GALES LINGER INTO THE EARLY
AFTERNOON DUE TO TIGHTER GRADIENT BUT WINDS ACROSS THE LAKE SHOULD
BE TRENDING DOWNWARD THIS AFTERNOON INTO TONIGHT AS RIDGE AXIS
APPROACHES FROM THE WEST. RIDGE WILL MOVE ACROSS THE LAKE TONIGHT
INTO MONDAY WITH SOUTHERLY WINDS DEVELOPING AND STRENGTHENING AS
SEASONABLY STRONG LOW PRESSURE DEVELOPS OVER THE SOUTHERN CANADIAN
PLAINS TUESDAY. DESPITE FAIRLY TIGHT GRADIENT...SURGE OF VERY WARM
AIR OVER VERY COLD LAKE SHOULD KEEP WINDS AND WAVES SOMEWHAT IN
CHECK TUESDAY INTO WEDNESDAY.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 3 PM SUNDAY.
GALE WARNING...LMZ366-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ868-
LMZ870-LMZ872-LMZ874 UNTIL 9 AM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 3 PM SUNDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
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AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
145 AM EDT SUN MAY 12 2013
.UPDATE...
ISSUED AT 145 AM EDT SUN MAY 12 2013
LINE OF SCATTERED SHOWERS CROSSING THE CWFA. NOT MUCH PCPN WITH THIS
LINE. AT CURRENT SPEED THE SHRA SHOULD BE EAST OF THE STATE BY 9Z.
THEN THE COLD AIR BEFINS TO MOVE IN. NOT EXPECTING DRAMATIC DROP IN
TEMPS TONIGHT DUE TO THE EXTENSIVE LOW LEVEL CLOUD COVER AND ENUF
WIND TO KEEP SOME OF THE BNDRY LAYER MIXED. SHOULD CLEAR ON SUN SO
SUN NIGHT WILL SEE THE REAL DROP IN OVERNIGHT TEMPS TO RECORD LEVELS
LIKELY. UPDATED GRIDS WITH CURRENT CONDITIONS. WILL UPDATE ZONES WHEN
THE SHRA EXIT THE AREA.
UPDATE ISSUED AT 1115 PM EDT SAT MAY 11 2013
A RECENT UPDATE WAS MADE TO THE GRIDS TO FINE TUNE TIMING OF SHOWER
CHANCES OVER THE NEXT FEW HOURS AND FRESHEN UP HOURLY
TEMPS...DEWPOINTS AND WINDS. THE COLD FRONT IS NOW MOVING THROUGH
CENTRAL KY WITH A BAND OF SHOWERS PRECEDING IT. COLDER AND DRIER AIR
WILL MOVE INTO THE AREA LATER TONIGHT BEHIND THE FRONT.
UPDATE ISSUED AT 810 PM EDT SAT MAY 11 2013
AT PRESENT...SOUTH CENTRAL AND EASTERN KY ARE IN A LULL BETWEEN THE
DEPARTED INITIAL FIRST COLD FRONT AND THE STRONGER SECOND COLD FRONT.
THIS COLD FRONT IS THE LEADING EDGE OF A MUCH COLDER AND DRIER
AIRMASS. ISOLATED TO SCATTERED SHOWERS ARE CURRENTLY ALONG THE
BOUNDARY...BUT OPERATIONAL MODELS INCLUDING THE HRRR AND NAM SHOW SOME
DECREASE IN ACTIVITY ALONG THE BOUNDARY WITH LOSS OF DAYTIME HEATING.
EXTRAPOLATION AND OPERATIONAL MODELS GENERALLY BRING THESE INTO THE
WESTERN COUNTIES AROUND OR A LITTLE BEFORE MIDNIGHT AND THEN DURING
THE OVERNIGHT HOURS ACROSS THE EASTERN HALF OF THE CWA. FEW CHANGES
WERE NEEDED TO THE PREVIOUS TIMING AND THE RECENT UPDATE WAS MAINLY
TO REMOVE AFTERNOON REFERENCES FROM THE ZFP AND ADJUST HOURLY
TEMPS...DEWPOINTS...SKY AND WINDS TO REFLECT RECENT TRENDS. THIS
SCENARIO BRING SOME PARTIAL CLEARING ACROSS THE CWA FOR AN HOUR OR
TWO BEFORE MORE CLOUDS MOVE IN ALONG THE BOUNDARY. ALTHOUGH THE
CURRENT BAND OF CLOUDS IS RATHER NARROW POST FRONTAL FLOW THAT IS OUT
OF THE NORTHWEST SHOULD TEND TO LINGER CLOUDS A LITTLE LONGER THAN
BAND OF CLOUDS TO THE WEST WOULD INDICATE AND THIS WAS ALREADY
HANDLED WELL IN THE PREVIOUS FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 354 PM EDT SAT MAY 11 2013
ISOLATED TO SCATTERED SHOWERS WILL WIND DOWN OVER THE NEXT COUPLE OF
HOURS AS THE SURFACE COLD FRONT HAS SHIFTED OFF TO THE SOUTHEAST OF
THE AREA. THE NEXT COLD FRONT IS CURRENTLY ALIGNED FROM NORTHEAST
INDIANA DOWN THROUGH SOUTHEAST MISSOURI. MOST OF THE SHOWER ACTIVITY
ASSOCIATED WITH THIS BOUNDARY IS LOCATED NORTH OF THE OHIO RIVER.
THE MODELS ARE IN GOOD AGREEMENT WITH BRINGING THIS SECONDARY
BOUNDARY THROUGH THE AREA LATER THIS EVENING...WITH ISOLATED TO
SCATTERED SHOWERS THREATENING ONCE AGAIN...ALTHOUGH MOST GUIDANCE
INDICATES A DOWNTREND IN CONVECTION AS THE BOUNDARY MOVES ACROSS
EASTERN KENTUCKY. LOWS TONIGHT WILL BOTTOM IN THE LOW TO MID 40S FOR
MOST LOCATIONS.
AFTER AN UNSEASONABLY COOL MOTHER/S DAY WITH HIGHS TOPPING OUT AT
AROUND 60 DEGREES...A CHILLY SUNDAY NIGHT WILL BE IN STORE. THE MODEL
GUIDANCE CONTINUES TO SHOW NEAR RECORD LOWS OF LOWER TO MIDDLE 30S.
HAVE THEREFORE HIGHLIGHTED THE COOLER TEMPERATURES AND THE
POSSIBILITY OF FROST IN AN SPS...ALTHOUGH WITH THE GREEN PRETTY MUCH
IN FULL SWING AND SATURATED GROUND FROM RECENT RAINFALL...THE FOG MAY
WIND UP BEING MORE PREVALENT THAN THE FROST.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 310 PM EDT SAT MAY 11 2013
THE MODELS START OUT THE EXTENDED IN EXCELLENT AGREEMENT ALOFT AS
THEY ALL HAVE A DEEP TROUGH EXTENDING FROM THE GREAT LAKES...
THROUGH THE OHIO VALLEY...AND TO THE DEEP SOUTH. THIS TROUGH WILL
QUICKLY PULL EAST DURING THE DAY MONDAY ALLOWING HEIGHTS TO RISE
OVER EAST KENTUCKY INTO MONDAY NIGHT. MODERATE RIDGING WILL THEN
BUILD INTO THE STATE FROM THE WEST AND LATER NORTH FROM THE CENTRAL
GULF COAST. BY WEDNESDAY MORNING...THOUGH...SOME DISTINCT
DIFFERENCES START TO CROP UP AMONGST THE MODELS IN BOTH THE NORTHERN
AND SOUTHERN STREAMS. A WELL DEFINED MID LEVEL LOW RUNNING EAST
ALONG THE CANADIAN BORDER...IN THE GFS...IS REPRESENTED AS A
WEAKER...MORE PROGRESSIVE...OPEN WAVE IN THE 00Z ECMWF. THE LATEST
GEM APPEARS TO BE SIDING WITH THE GFS WITH THIS FEATURE. THE NET
RESULT FOR EAST KENTUCKY WILL BE SIMILAR REGARDLESS OF WHICH SOLUTION
PANS OUT AS THERE REMAINS GOOD AGREEMENT THAT RIDGING WILL BE IN
PLACE OVER OUR AREA THROUGH MIDWEEK. WHILE THE NORTHERN DETAILS WORK
THEMSELVES OUT...TO THE SOUTH A WEAKENING IMPULSE WILL MOVE THROUGH
THE SOUTHERN PLAINS LIKELY SERVING TO SUPPRESS THE LOCAL RIDGING AS
IT MOVES CLOSER TO THE CWA ON THURSDAY. IN FACT...BY 00Z FRIDAY THE
GFS IS SHOWING A FLAT TO SLIGHTLY TROUGHING PATTERN OVER EAST
KENTUCKY WHILE THE ECMWF STILL HAS THE BACK EDGE OF RIDGING HOLDING
ON THROUGH THE APPALACHIANS. DESPITE THE PATTERN DIFFERENCES...THE
HEIGHTS ARE RATHER SIMILAR OVER THE AREA INTO FRIDAY...ALONG WITH A
HEALTHY MIX OF ENERGY...KEEPING THINGS UNSETTLED. FOR SATURDAY...
WEAK RIDGING WILL REMAIN IN PLACE THROUGH THE AREA AS ANY IMPRESSIVE
WAVES STAY WELL NORTH OF THE AREA...MORE BEFITTING OF THIS TIME OF
YEAR. GIVEN THE SIMILARITY AND GENERAL CONSENSUS EXHIBITED BY THE
MODELS OVER EAST KENTUCKY THROUGH THE PERIOD...WILL FOLLOW A BLENDED
SOLUTION WITH LITTLE APPREHENSION...AND SOME CONFIDENCE THAT A MORE
NORMAL LATE SPRING WX PATTERN IS NEARLY UPON US.
AS FOR SENSIBLE WEATHER...MONDAY WILL START OUT CHILLY AND FROSTY
BUT MODERATE QUICKLY A HIGH PRESSURE MOVES INTO THE OHIO VALLEY. THE
WARMING WILL CONTINUE INTO TUESDAY AS A WARM FRONT PASSES TO THE
NORTH OF THE AREA. THIS WILL SET THE STAGE FOR A RARITY OF THIS
SPRING...A DAY OF ABOVE NORMAL TEMPERATURES...ON WEDNESDAY. ABOUT
THIS TIME A DEVELOPING FRONT SETS UP NORTH OF THE OHIO RIVER AND
INCREASING MOISTURE WILL BRING WITH IT BETTER CHANCES FOR CONVECTION
ON THURSDAY. THIS NEARBY FRONT...A MOIST BOUNDARY LAYER...AND WARM
TEMPERATURES WILL LIKELY KEEP...AT LEAST DIURNALLY DRIVEN...SHOWERS
AND THUNDERSTORMS AROUND THROUGH THE END OF THE WEEK AND INTO
SATURDAY. THE PRICE OF A MORE NORMAL SPRING PATTERN...AND A LACK OF
STRONG HIGH PRESSURE...DURING THE LATTER PART OF THE FORECAST WILL
BE A PATTERN MORE SIMILAR TO EARLY SUMMER MAKING AFTERNOON AND
EVENING CONVECTION A GOOD BET.
THE CR GRID LOAD CAME IN PRETTY GOOD...DID MAKE HOURLY ADJUSTMENTS
TO THE POPS AND SKY COVER TO BETTER HONE IN ON THE TIMES OF PEAK
CONVECTION FROM THURSDAY ON. ALSO...MADE SOME TERRAIN BASED
ADJUSTMENTS TO LOW TEMPERATURES EACH NIGHT FROM MONDAY THROUGH
WEDNESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 815 PM EDT SAT MAY 11 2013
DURING THE FIRST 3 TO 7 HOURS OF THE PERIOD...THE REGION WILL BE A
RELATIVE LULL IN CLOUDS BETWEEN THE DEPARTED COLD FRONT AND ANOTHER
APPROACHING COLD FRONT AND ASSOCIATED BAND OF CLOUDS AND SCATTERED
SHOWERS. DURING THE LULL AN IMPROVEMENT TO VFR SHOULD OCCUR IN ALL
BUT THE HIGHEST TERRAIN THE SOUTHEAST WHERE SKIES SHOULD IMPROVE TO
MVFR FROM IFR. A DROP DOWN TO MVFR OR PERHAPS LOWER IS ANTICIPATED
ALONG AND FOR ABOUT 3 HOURS BEHIND THE BOUNDARY. DRY AIR ADVECTION IN
LOWER LEVELS SHOULD LEAD TO IMPROVEMENTS BACK TO VFR AFTER THAT PERIOD.
WINDS WILL BE A BIT GUSTY FROM NW OR NNW...ESPECIALLY 15Z TO 22Z.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DUSTY
SHORT TERM...GEOGERIAN
LONG TERM...GREIF
AVIATION...JP
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1010 PM EDT MON MAY 13 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD EAST OVERNIGHT THROUGH TUESDAY...THEN CROSS
THE REGION THROUGH WEDNESDAY. A WARM FRONT WILL CROSS THE REGION
WEDNESDAY NIGHT INTO THURSDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
1000 PM UPDATE: ADJUSTED THE SKY CONDITIONS TO ADD MORE CLOUDINESS
ACROSS THE EASTERN 3RD OF THE CWA IN RESPONSE THE LOW PASSING WELL
E OF THE REGION. MOST OF THIS CLOUDINESS IS OF MID/HIGH LEVEL.
CANADIAN GEM AND HRRR DOING WELL IN CATCHING THESE CLOUDS AND
LATEST FCST HAS THESE CLOUDS PULLING E OVERNIGHT W/CLEARING TAKING
PLACE. FROST ADVISORY REMAINS IN PLACE FOR THE CENTRAL HIGHLANDS
AND DOWNEAST.
WINDS WILL BECOME LIGHT AND THE COOL DRY AIR WILL ALLOW TEMPS TO
FALL TO NEAR OR JUST BELOW FREEZING ACROSS THE NORTH OVERNIGHT.
LOWS IN THE MID 30S OVER INTERIOR DOWNEAST LOCATIONS WILL ALLOW
FROST TO FORM INLAND FROM THE COAST. A FROST ADVISORY WILL BE
ISSUED FOR INTERIOR DOWNEAST LOCATIONS WHERE THE OUTDOOR GROWING
SEASON MAY HAVE STARTED FOR SOME GARDENERS. A FREEZE IS LIKELY
ACROSS THE NORTH. HIGH PRESSURE WILL BRING LIGHT WINDS AND A
MODERATELY COOL DAY ACROSS THE AREA ON TUESDAY. CUMULUS CLOUDS
WILL BRING PARTIAL SUNSHINE DURING THE MIDDAY. SOME HIGH THIN
CLOUDS MAY BRUSH EASTERN AREAS FROM THE WESTERN EDGE OF A LOW
PRESSURE SYSTEM PASSING SOUTHEAST OF NOVA SCOTIA.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
LOW PRESSURE WILL LIFT NORTH ACROSS NOVA SCOTIA TUESDAY NIGHT
WHILE HIGH PRESSURE BUILDS EAST ACROSS THE FORECAST AREA. EXPECT
PRECIPITATION WITH THE MARITIMES LOW WILL REMAIN JUST EAST OF THE
REGION...THOUGH THE EDGE OF THE CLOUD SHIELD WILL CLIP EASTERN
PORTIONS OF THE FORECAST AREA EARLY TUESDAY NIGHT. CLOUD COVER
WILL THEN DECREASE ACROSS THE REGION OVERNIGHT WITH BUILDING HIGH
PRESSURE. FREEZING TEMPERATURES WILL BE A CONCERN ACROSS NORTHERN
AREAS TUESDAY NIGHT...WITH THE COLDEST TEMPERATURES ACROSS
NORTHWEST AREAS. FROST ADVISORIES COULD BE NEEDED DOWNEAST WHERE
THE GROWING SEASON HAS ALREADY STARTED. HIGH PRESSURE WILL CROSS
THE REGION WEDNESDAY. CLOUD COVER WILL BEGIN TO INCREASE WEDNESDAY
AFTERNOON IN ADVANCE OF AN APPROACHING WARM/OCCLUDED FRONT. THE
FRONT WILL CROSS THE REGION WEDNESDAY NIGHT INTO THURSDAY...THOUGH
UNCERTAINTY WITH THE EXACT TIMING OF THE FRONT AND RAIN TOTALS
STILL EXIST. EXPECT AN AREA OF RAIN WILL CROSS THE REGION
WEDNESDAY NIGHT IN ADVANCE OF THE FRONT...WITH THE STEADIER RAIN
TAPERING TO SHOWERS LATE. COULD STILL HAVE A CHANCE OF SHOWERS
ACROSS THE REGION THURSDAY INTO THURSDAY NIGHT...WITH THE BETTER
CHANCES OF SHOWERS AND MORE EXTENSIVE CLOUD COVER ACROSS NORTHERN
AREAS. HIGH TEMPERATURES WILL BE AT NEAR NORMAL LEVELS
WEDNESDAY/THURSDAY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
THE BASE OF A UPPER LEVEL LOW WILL BE MOVING ACROSS THE NORTHERN
PART OF THE REGION TO BEGIN THE FORECAST PERIOD. THIS WILL BRING
CLOUDS AND SHOWERS MAINLY ACROSS THE NORTH FOR FRIDAY. THE UPPER
LEVEL LOW WILL KEEP CLOUDS AND SOME SHOWERS FRIDAY NIGHT AS SYSTEM
SLIDES EAST. THE DIVERGENCE IN THE MODELS COMES WITH RESPECT TO
TIMING OF THE NEXT SYSTEM. THE 06Z GFS BRINGS A BOUNDARY INTO THE
REGION BY SUNDAY AFTERNOON WHILE THE 00Z ECMWF IS QUITE A BIT
SLOWER BRING PRECIP IN MONDAY NIGHT. 00Z GFS ENSEMBLE MEAN ALSO
BRINGS THIS SYSTEM INTO THE SUNDAY EVENING. THE LATEST 12Z GFS
ALSO WANTS TO HINT AT THE POSSIBILITY OF SOME SHOWER ACTIVITY BY
SUNDAY AFTERNOON BUT BRINGS LESS LIFT ACROSS THE REGION. RIGHT NOW
WITH LOW CONFIDENCE WILL BRING SHOWERS MAINLY IN THE WESTERN
PORTIONS OF THE AREA FOR SUNDAY AFTERNOON INTO MONDAY. WILL LOAD
WITH GMOS AND ADJUST ACCORDINGLY LEANING TOWARD PREVIOUS FORECAST
TO KEEP SOME CONSISTENCY AT THE END OF THE PERIOD.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: VFR CONDITIONS ARE EXPECTED ACROSS THE AREA TONIGHT AND
TUESDAY.
SHORT TERM: VFR CONDITIONS ARE EXPECTED ACROSS THE REGION TUESDAY
NIGHT THROUGH WEDNESDAY. CONDITIONS WILL LOWER TO MVFR/IFR LEVELS
WEDNESDAY NIGHT INTO EARLY THURSDAY. OCCASIONAL MVFR CONDITIONS
ARE POSSIBLE ACROSS THE REGION THURSDAY INTO THURSDAY NIGHT. THE
POSSIBILITY OF MVFR CONDITIONS WITH SHOWERS MAINLY ACROSS THE NORTH
FOR FRIDAY WITH SITES GOING VFR FOR SATURDAY.
&&
.MARINE...
NEAR TERM: WINDS WILL DIMINISH TONIGHT. SEAS WILL REMAIN ABOVE 5
FT OVERNIGHT REQUIRING AN SCA FOR HAZARDOUS SEAS. SEAS ARE
EXPECTED TO DROP BELOW 5 FT TUESDAY AND WIND WILL BE LIGHT WITH
HIGH PRESSURE BUILDING OVER.
SHORT TERM: WINDS/SEAS ARE EXPECTED TO BE BELOW SMALL CRAFT
ADVISORY LEVELS TUESDAY NIGHT. MARGINAL SMALL CRAFT ADVISORY
LEVEL SEAS ARE POSSIBLE WEDNESDAY. SMALL CRAFT ADVISORY
CONDITIONS ARE POSSIBLE WEDNESDAY NIGHT INTO THURSDAY...WITH SMALL
CRAFT ADVISORY LEVEL SEAS PERSISTING INTO THURSDAY NIGHT.
VISIBILITIES WILL BE REDUCED IN RAIN/FOG WEDNESDAY NIGHT...WITH
LINGERING SHOWERS THURSDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...FROST ADVISORY FROM 2 AM TO 6 AM EDT TUESDAY FOR MEZ011-
015>017-031-032.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 AM EDT TUESDAY
FOR ANZ050-051.
&&
$$
NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1255 AM EDT SUN MAY 12 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH LATER TONIGHT AND CROSS THE REGION ON
SUNDAY WITH ADDITIONAL AFTERNOON SHOWERS. COLDER AND DRIER AIR WILL
FOLLOW FOR EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
1255 AM UPDATE...MAIN CHANGES WITH THIS UPDATE WERE TO POPS TO
MATCH THEM TO CURRENT RADAR TRENDS. THE FRONT IS BISECTING THE
FORECAST AREA RIGHT NOW AND SHOWERS HAVE PRETTY MUCH HAVE COME TO
AN END ACROSS NORTHWESTERN MAINE. THE BEST CHANCES FOR
PRECIPITATION FOR THE REMAINDER OF TONIGHT/THIS MORNING WILL BE
ACROSS FAR DOWNEAST AREAS, AS RADAR SHOWS AN OFFSHORE BAND OF
WIDESPREAD SHOWERS WILL CONTINUE BRUSH COASTAL AREAS. ELSEWHERE,
SHOWERS WILL BE SCATTERED IN NATURE. OTHER THAN POPS, THE GOING
FORECAST WAS ON TRACK, SO NO OTHER CHANGES WERE NEEDED.
PREVIOUS DISCUSSION: MAIN CHALLENGES WILL BE TIMING OF RAIN
TONIGHT INTO SUNDAY AND TEMPERATURES.
FIRST AREA OF RAIN MOVING TO THE E INTO NEW BRUNSWICK WHILE SEND
AREA OF RAIN AND POSSIBLE TSTMS MOVING INTO SWRN AREAS ATTM PER
THE LATEST RADAR. THIS SECOND AREA OF RAIN WILL OVERSPREAD THE CWA
LATER THIS AFTERNOON INTO EARLY TONIGHT. 12Z UA INDICATED A STRONG
40KT JETLET AT 700MBS ACROSS ONTARIO AND WRN NYS. THIS AREA OF
FORCING WAS PICKED UP BY THE GFS AND CANADIAN GEM. THEREFORE, A
BLEND OF THESE 2 MODELS WERE USED INTO EARLY TONIGHT AS THEY SHOW
A SIGNIFICANT AREA OF RAIN MOVING ACROSS THE REGION. ATMOSPHERE
LOOKS LIKE IT STABILIZES AFTER 22Z AND THEREFORE CUT BACK ON THE
MENTION OF TSTMS FOR OUR CWA. THE LATEST RAP FROM THE SPC MESO-
ANALYSIS PAGE INDICATED SOME POSSIBLE TSTMS EDGING INTO GYX/S WRN
ZONES THIS AFTERNOON AND THEN WEAKENING BY 22Z OR SO. A BLEND OF
THE NERFC/GFS AND SREF WAS USED FOR THE QPF WHICH SHOWED AN
ADDITIONAL 0.15-0.30 THROUGH 06Z AND THEN RAIN END AS THE BEST
FORCING EXITS INTO NEW BRUNSWICK. ADDED FOG FOR ALL THE CWA
OVERNIGHT W/THE MOST DENSE FOG FROM MLT REGION ON SOUTH.
TEMPERATURES WILL BE HELD UP TONIGHT AND FOLLOWED A BLEND OF THE
NAM12 AND REGIONAL GEM FOR TONIGHT`S LOWS SHOWING UPPER 40S OUT
WEST TO LOW TO MID 50S EASTERN AND CENTRAL AREAS.
FOR SUNDAY, DRY W/SOME FOG TO START AND THEN ANOTHER BATCH OF
SHOWERS EXPECTED BY MIDDAY DUE TO THE COLD FRONT APCHG FROM THE W.
STAYED W/A GEM/GFS BLEND FOR TIMING OF THE SHOWERS USING THE MID
LEVEL FORCING FOR THE QPF WHICH SHOWED ANOTHER .10-.20, MAINLY
NORTHERN AND CENTRAL AREAS. HELD BACK THE TEMPERATURES FROM PREVIOUS
THINKING AND LEANED W/LOWER 60S NORTH AND MID 60S CENTRAL AND
DOWNEAST AS CAA LOOKS TO TAKE HOLD IN THE AFTERNOON. TSTM
POTENTIAL LOOKS TO BE LESS LIKELY ESPECIALLY ACROSS THE DOWNEAST
AND COAST DUE TO THE ONSHORE FLOW. BEST CHANCES IF ANY WILL BE
ACROSS THE NORTHERN AND WESTERN AREAS DUE TO SOME ELEVATED
INSTABILITY. ATTM, KEPT ISOLATED THUNDER IN THERE FOR CONTINUITY.
MIDNIGHT CREW CAN ASSESS THIS FURTHER TONIGHT.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
THE FIRST PART OF THE PERIOD WILL BEGIN WITH SHOWERS ACROSS THE
NORTHERN AND CENTRAL PARTS OF THE REGION SUNDAY NIGHT. THESE
SHOWERS ARE DUE TO A BOUNDARY THAT WILL MOVE FROM WEST TO EAST.
THE BEST LIFT LOOKS TO BE ACROSS THE NORTH. ONCE THIS FRONTAL
BOUNDARY PUSHES THROUGH THE REGION TEMPERATURES WILL COOL OFF FOR
MONDAY WITH HIGHS IN THE 50S NORTH AND THE UPPER 50S TO LOWER 60S
SOUTH. AS THE UPPER LEVEL TROUGH MOVES EAST THE 12Z GFS IS TRYING
TO CLOSE THE TROUGH TO THE NORTH WHILE THE 12Z NAM/00Z ECMWF
CONTINUE TO DEVELOP THE CLOSED LOW AROUND THE BASE OF THE TROUGH.
RIGHT NOW WILL LEAN WITH THE SURFACE LOW DEVELOPS TRACKING MAINLY
EAST OF THE AREA LATE TUESDAY INTO TUESDAY NIGHT. MAIN AFFECT TO
THE FORECAST FOR THIS PERIOD WILL BE THE INCREASE IN CLOUDS
COVERAGE WITH HIGHEST COVERAGE SEEN ACROSS THE EASTERN AND
SOUTHEASTERN PARTS OF THE REGION.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
BOTH MEDIUM RANGE MODELS ARE IN GENERAL AGREEMENT IN THE TUESDAY
NIGHT THROUGH THROUGH SUNDAY TIME FRAME. THE FORECAST FOR
WEDNESDAY CONTINUES TO BE DRY. MOISTURE INCREASES WEDNESDAY
NIGHT...AHEAD OF THE NEXT SYSTEM EXPECTED TO MOVE THROUGH THE
AREA...BRINGING A CHANCE OF RAIN MAINLY ON THURSDAY. AT THIS POINT
IT APPEARS WE MAY HAVE A BREAK BETWEEN SYSTEMS ON FRIDAY HOWEVER
LATE FRIDAY INTO SATURDAY SHOULD SEE RAIN CHANCES INCREASE ACROSS
THE REGION ONCE AGAIN. SEASONAL TEMPERATURES ARE EXPECTED THROUGH
THE PERIOD WITH SOME DAYS A LITTLE ABOVE NORMAL AND OTHERS WITH
READINGS A LITTLE BELOW.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: IFR INTO SUNDAY MORNING AND THEN CONDITIONS GO TO MVFR
ESPECIALLY NORTHERN TERMINALS.
SHORT TERM: MOST TAF SITES WILL STAY VFR THROUGH THE PERIOD
EXCEPT FOR SUNDAY NIGHT WITH HEAVIER SHOWERS THERE COULD BE
PERIODS OF MVFR OR IFR.
&&
.MARINE...
NEAR TERM: DECIDED TO TRANSITION THE SCA TO HAZARDOUS SEAS INTO
SUNDAY. WAVES ARE CLIMBING TO 6 ATTM W/A SWELL GENERATED. WILL
CARRY THE MENTION OF THE SWELL INTO SUNDAY. WINDS ARE BELOW SCA
AND EXPECTING THEM TO STAY BELOW INTO SUNDAY. FOLLOWED THE
NAM12/GFS40 BLEND FOR THE WINDS AND FOLLOWED CLOSELY W/THE
MIDNIGHT CREW`S WAVE HEIGHTS OF 4-7 FT.
SHORT TERM: SCA CONDITIONS SUBSIDE BY THE SHORT TERM PERIOD.
KEPT CONSISTENCY WITH LAST NIGHTS SHIFT FOR WAVE AND WIND GRIDS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 PM EDT THIS
AFTERNOON FOR ANZ050>052.
&&
$$
NEAR TERM...HASTINGS/HEWITT
SHORT TERM...JORDAN
LONG TERM...RUNYAN
AVIATION...HASTINGS/HEWITT/JORDAN
MARINE...HASTINGS/HEWITT/JORDAN
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
738 PM EDT MON MAY 13 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 351 PM EDT MON MAY 13 2013
TWO WAVES/DISTURBANCES WILL BE THE FOCUS FOR THE FORECAST...WITH
THE FIRST ONE AFFECTING THE AREA TONIGHT AND THE OTHER TOMORROW
AFTERNOON/EVENING.
LATEST WV IMAGERY AND RUC ANALYSIS SHOWS THE AREA UNDER RIDGING
ALOFT AS THE UPPER TROUGH THAT HAD BEEN AFFECTING THE AREA THIS
WEEKEND SHIFTING EAST ACROSS QUEBEC AND AN UPPER RIDGE OVER THE
WESTERN CONUS. THERE IS A DECENT AMOUNT OF MOISTURE ROUNDING THE
RIDGE WITH A 996MB LOW JUST TO THE WEST OF LAKE WINNIPEG. CLOSER TO
HOME...SKIES WERE CLEAR OVER MUCH OF UPPER MICHIGAN THIS
MORNING...BUT INCREASING MID-HIGH CLOUDS ARE SPREADING ACROSS THE
AREA THIS AFTERNOON. BAND OF RAIN IS STARTING TO MOVE INTO WESTERN
LAKE SUPERIOR AT THIS TIME AND IS ASSOCIATED WITH A THIN AREA OF
800-500MB MOISTURE AND 700MB F-GEN.
EXPECT THE BAND TO CONTINUE EAST-SOUTHEAST THIS EVENING AS THE
700MB F-GEN AND BROAD 850-700MB WARM AIR ADVECTION CONTINUE.
BUT...WITH THE 500MB SHORTWAVE AND ASSOCIATED HEIGHT FALLS SHIFTING
EAST THROUGH ONTARIO AND WELL NORTH OF THE AREA ALONG WITH BEING
UNDER THE WRONG AREA OF THE UPPER JET /RIGHT EXIT/ THE BETTER
FORCING ISN/T OVER THE AREA. PLUS...WITH THE DRY AIR IT WILL BE
RUNNING INTO...WONDERING IF THAT WILL LIMIT THE INTENSITY SOME.
WITH AS PERSISTENT AS IT HAS BEEN TODAY...DID BUMP UP POPS A
TOUCH TO GET MORE CHANCE/SCATTERED WORDING IN FOR THIS
EVENING...BUT BASED OFF THE LIMITED RAIN AMOUNTS SEEN UPSTREAM
/TRACE TO A COUPLE HUNDREDTHS/ DIDN/T WANT TO GO MUCH ABOVE THAT. AS
ADDITIONAL 850-700MB MOISTURE SLIDES SOUTHEAST ACROSS THE EASTERN
CWA TONIGHT...WOULD THINK THE PRECIPITATION CHANCES SHOULD INCREASE
SOME OVERNIGHT. THERE IS LITTLE OR NO INSTABILITY WITH THIS PASSING
WAA...AS MID LEVEL LAPSE RATES ARE ONLY AROUND 3-5 C/KM...SO WILL
KEEP THUNDER OUT OF THE FORECAST. WITH THE BETTER CONSISTENCY IN
THIS MOISTURE ARRIVING OVER THE EAST...DID BUMP UP VALUES TO HIGH
CHANCE POPS THERE.
EXPECT TO SEE A BRIEF REPRIEVE ON TUESDAY MORNING BEHIND THE INITIAL
AREA OF WAA TONIGHT. THIS WILL LIKELY PRODUCE SOME BREAKS OR
CLEARING OVER AT LEAST THE WEST HALF OF THE CWA DURING THE MORNING
HOURS BEFORE MID-HIGH CLOUDS STREAM BACK INTO THE AREA. THEN...THE
SHORTWAVE THAT IS CURRENTLY ENTERING THE PACIFIC NORTHWEST WILL BE
MOVING EAST-NORTHEAST ALONG THE US/CANADIAN BORDER AND BE NEAR LAKE
WINNIPEG BY 18Z TUESDAY. WARM AIR ADVECTION WILL AGAIN BE ON THE
INCREASE FROM WEST TO EAST DURING THE AFTERNOON. MOISTURE WILL ALSO
BE LIMITED AS IT MOVES THROUGH THE AREA DURING THE AFTERNOON. BEST
MOISTURE AND CLOSEST PROXIMITY TO THE SHORTWAVE WILL BE OVER THE
NORTHWEST HALF OF THE CWA...SO WILL HAVE HIGHEST POPS THEIR DURING
THE LATTER PART OF THE AFTERNOON. QPF/REFLECTIVITY FROM HIGH
RESOLUTION MODEL RUNS SEEM TO MATCH THIS IDEA AND LEADS TO GREATER
CONFIDENCE.
ELEVATED INSTABILITY IS MARGINAL ALONG/NORTH THE WARM FRONT...WITH
THE BEST INSTABILITY FARTHER SOUTHWEST AND AHEAD OF THE COLD
FRONT. THIS IS LARGELY DUE TO THE MID-LEVEL LAPSE RATES STRUGGLING
TO GET ABOVE 6C/KM. THUS...THUNDER POTENTIAL WILL BE SLIM THROUGH
THE AFTERNOON HOURS. IF ANY ELEVATED THUNDERSTORMS
DEVELOP...WOULDN/T EXPECT THEM TO BE TOO STRONG...AS EFFECTIVE SHEAR
VALUES WILL LIKELY BE BELOW 30KTS THROUGH 00Z ACROSS ALL BUT THE FAR
SOUTHWEST CWA.
AFTER A COOL WEEKEND...TEMPERATURES HAVE STARTED TO REBOUND TODAY
AND EXPECT IT TO CONTINUE ON TUESDAY. THE WARM AIR ADVECTING INTO
THE AREA ON TUESDAY ALONG WITH INCREASING SOUTHERLY FLOW SHOULD LEAD
TO HIGHS IN THE LOWER 70S OVER THE FAR WEST AND A GRADIENT TO THE
50S OVER THE EAST HALF.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 351 PM EDT MON MAY 13 2013
MUCH OF THIS PERIOD WILL BE MARKED BY THE PRESENCE OF A 70KT OR
GREATER 250MB JET OVER UPPER MICHIGAN AND/OR LAKE SUPERIOR...AT
LEAST FROM TUESDAY NIGHT THROUGH SATURDAY MORNING. THIS WILL KEEP
THE AREA IN A RELATIVELY BUSY WEATHER PATTERN...IN BETWEEN THE DOME
OF HOT AIR OVER MUCH OF THE WESTERN HALF OF THE NATION...AND COLDER
AIR RESIDING OVER CANADA.
WE WILL START OUT TUESDAY NIGHT WITH A STACKED 500MB TROUGH-SFC LOW
SET UP JUST NORTH OF CYRL IN WESTERN MANITOBA. A COLD FRONT WILL
EXTEND S FROM THE SFC LOW...THROUGH THE EASTERN THIRD OF MN TO A
SECONDARY SFC LOW/TRIPLE POINT THAT MAY BE DEVELOPING NEAR KDLH.
THE LOCATION OF THE WARM FRONT IS KEY...LIKELY SET UP FROM THE
ARROWHEAD OF MN DOWN AND NEAR THE WI BORDER OF UPPER MI AT 00Z
WEDNESDAY. AS IS TYPICAL...THESE SPLITTING SYSTEMS CAN DEVELOP AND
ROB US OF MOISTURE...AS CONVECTION POPS UP OVER WI. EXPECT
WAA...LIMITED FORCING WILL LIKELY PERSIST...WITH MUCH OF THE BEST
FORCING CLOSER TO THE MAIN SFC/500MB TROUGH ACROSS ONTARIO /WHERE AN
AVERAGE QUARTER OF AN INCH OR MORE OF RAIN IS EXPECTED/. WE LOOK TO
BE IN A PRETTY CAPPED ENVIRONMENT...WITH THE BEST CHANCE FOR ANY
STRONGER SHOWERS OR THUNDERSTORMS OVER SOUTH CENTRAL AND EASTERN
UPPER MI DURING THE LATE EVENING HOURS...AND EVEN THEN LIKELY
ELEVATED ABOVE THE DRY AIR. THE SOUTHERN LOW/COLD FRONT WILL BE OVER
EASTERN UPPER MI/LAKE SUPERIOR BY 09Z WEDNESDAY...AND EAST OF UPPER
MI BY 12Z.
COOLER/DRIER AIR WILL SWEEP IN FOR WEDNESDAY...WITH 850MB TEMPS
FALLING FROM A MAX 14-18C OVERNIGHT TO AN AVERAGE 7-8C DURING THE
DAY WEDNESDAY. PW VALUES FALL TO 0.37 TO 0.44IN...OR 60-70 PERCENT
OF NORMAL...WITH THE LOWEST VALUES AWAY FROM THE KEWEENAW PENINSULA
AND EXTREME S CENTRAL UPPER MI. EXPECT A MORE MODERATED AIRMASS FROM
MUNISING EASTWARD AS MORE MOIST AIR SLIDES IN NEAR THE SHORELINE. A
WORST CASE SCENARIO...WITH THE NAM MIXING UP TO 650-700MB DURING THE
AFTERNOON HOURS...DEW POINTS MIXING DOWN INTO THE UPPER 20S
/F/ WOULD RESULT IN AFTERNOON MIN RH VALUES OF 19-25 PERCENT FROM
JUST E OF IWD TO NORTHERN DELTA COUNTY...WITH GUSTS 25-30KTS. ON A
POSITIVE NOTE...THE LATEST MODEL RUNS ARE NOT QUITE AS STRONG WITH
THE WINDS. WILL NEED TO WAIT AND SEE IF THIS TREND HOLDS. IF
LIMITED...OR NO...PRECIPITATION FALLS TUESDAY NIGHT...FIRE CONCERNS
WILL BE ELEVATED.
BEHIND THE ELONGATED LOW SHIFTING EAST INTO QUEBEC WEDNESDAY
NIGHT...DRY WEATHER WILL REMAIN THROUGH FRIDAY MORNING...WITH COOL
WEST TO NORTHWEST FLOW LINGERING. EXPECT THE RIDGE OF HIGH PRESSURE
TO BE DIRECTLY OVERHEAD ON THURSDAY...WITH LIGHT WINDS AND LAKE
BREEZES EXPECTED.
OUR NEXT WEATHER MAKER WILL BE ORGANIZING ACROSS THE CENTRAL PLAINS
FRIDAY NIGHT THROUGH SATURDAY...BEFORE SHIFTING TOWARD MN AND IA
SATURDAY NIGHT. THE SFC LOW WILL SIT AND SPIN BEFORE FINALLY EXITING
NORTHEASTWARD ACROSS W LAKE SUPERIOR AROUND 06Z MONDAY AND SOUTHERN
ONTARIO DURING THE DAY MONDAY...AS THE 500MB TROUGH/LOW DIVES ACROSS
THE NORTHERN PLAINS SUNDAY INTO SUNDAY NIGHT. ADDED TS CHANCES
SATURDAY THROUGH MONDAY MORNING...BEFORE THE END TO THE BULK OF
MOISTURE. AT THIS POINT IT LOOKS LIKE THERE WILL BE A GOOD CHANCE OF
SOAKING RAIN OVER THE FAR W PORTIONS OF UPPER MI FRIDAY NIGHT
THROUGH SATURDAY...WITH ANOTHER ROUND POSSIBLE LATER SUNDAY INTO
MONDAY AS THE COLD FRONT SWINGS THROUGH.
OTHER THAN SUNDAY TIMING DIFFERENCES BETWEEN THE 12Z RUNS OF THE GFS
AND ECMWF...THE FCST MODELS ARE IN NORMAL TO SLIGHTLY ABOVE NORMAL
AGREEMENT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 737 PM EDT MON MAY 13 2013
VFR CONDITIONS TO PERSIST AT ALL THREE TAF SITES THROUGH THE
FORECAST. UPPER LEVEL DISTURBANCE PUSHING CLOUD COVER AND RAIN
SHOWERS INTO THE AREA THIS EVENING...BUT PRECIPITATION HAS BEEN VERY
SPOTTY DUE TO DRY AIR IN PLACE ASSOCIATED WITH RETREATING HIGH
PRESSURE. KIWD IS ON THE BACKSIDE OF THE BETTER FORCING AND THUS
HAVE REMOVED MENTION OF VCSH THERE...BUT KEPT IT IN FOR KCMX AND
KSAW. DISTURBANCE WILL SHIFT EAST OVERNIGHT WITH CLOUD COVER
DECREASING. WILL LEAVE IN MENTION OF LLWS AT KSAW AND KIWD AS BUFKIT
SOUNDINGS SHOW STRONG WINDS ALOFT THIS EVENING AS THE DISTURBANCE
MOVES THROUGH. NEXT DISTURBANCE APPROACHES THE REGION IN THE MORNING
WITH INCREASING HIGH AND MID LEVEL CLOUDS...WITH A POSSIBILITY OF
LIGHT SHOWERS OVER KCMX BY 0Z. HAVE LEFT OUT OF FORECAST FOR NOW AS
TIMING OF ARRIVAL MAY BE DELAYED SLIGHTLY BEYOND THE CURRENT
FORECAST PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 351 PM EDT MON MAY 13 2013
HIGH PRESSURE WILL DEPART THE AREA THIS EVENING. THIS WILL LEAD TO
INCREASING SOUTHERLY FLOW TONIGHT INTO TUESDAY AHEAD OF A LOW
PRESSURE SYSTEM MOVING EAST THROUGH SOUTHERN CANADA. AT THIS
POINT...THE INCREASING WARM AIR ABOVE THE SURFACE SHOULD LIMIT GUST
TO 20KTS IN MOST LOCATIONS FOR OVERNIGHT TONIGHT AND TUESDAY.
DISPITE A COUPLE OF SIGNIFICANT SYSTEMS PUSHING THROUGH THE AREA
TUESDAY-TUESDAY NIGHT...AND AGAIN THIS WEEKEND...WINDS ARE CURRENTLY
ANTICIPATED TO REMAIN BELOW 30KTS. IT IS THAT TIME OF YEAR
AGAIN...THERE WILL BE A ROUND OF THUNDERSTORMS POSSIBLE TUESDAY
AFTERNOON OVER WESTERN LAKE SUPERIOR...PUSHING EASTWARD OVERNIGHT
AND ENDING EARLY WEDNESDAY. ANOTHER ROUND OF THUNDERSTORMS WILL BE
POSSIBLE WEST ON SATURDAY/SATURDAY NIGHT...AND ACROSS ALL OF LAKE
SUPERIOR SUNDAY THROUGH MONDAY MORNING.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KF
AVIATION...RJT
MARINE...SRF/KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
406 PM EDT SUN MAY 12 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 404 PM EDT SUN MAY 12 2013
WV IMAGERY AND RUC ANALYSIS INDICATED AN AMPLIFIED PATTERN WITH A
RIDGE OVER WRN NOAM AND A TROUGH OVER THE EAST. THE MID LEVEL LOW
CENTER WAS SLOWLY MOVING OFF TO THE EAST OF CYSB INTO QUEBEC. AT THE
SFC...THE PRES GRADIENT ACROSS LAKE SUPERIOR WAS GRADUALLY WEAKENING
AS THE 998 MB LOW ALSO MOVES INTO QUEBEC AND A RIDGE RIDGE FROM NW
ONTARIO THROUGH WRN MN BUILDS INTO THE UPPER MS VALLEY. RADAR
INDICATED THAT THE LINGERING FLURRIES BTWN MQT-ESC-ISQ WERE
DIMINISHING AS DRIER AIR MOVES IN .
TONIGHT...EXPECT THAT THE REST OF THE LOWER CLOUDS WILL DISSIPATE
DURING THE LATE AFTERNOON AND EARLY EVENING...PER SATELLITE
TRENDS...BUT MAY LINGER A BIT LONGER THAN WHAT SHORT TERM MODEL LOW
LEVEL RH GUIDANCE SUGGESTS. WITH GOOD RADIATIONAL COOLING CONDITIONS
BY LATE THIS EVENING WEST AND OVER NIGHT EAST AND PWAT VALUES BELOW
0.25 INCH...MIN TEMPS SHOULD FALL TOWARD THE LOWER END OF GUIDANCE
AND NEAR RECORD VALUES. THE RECORD FOR THE NWS OFFICE ON 5/12 IS 24
AND ON 5/13 IS 25. READINGS INTO THE UPPER TEENS INTERIOR WEST TO THE
MID 20S EAST ARE EXPECTED WHILE TEMPS AROUND 30 PREVAIL NEAR THE
GREAT LAKES.
MONDAY...AS THE MID/UPPER LEVEL RIDGE OVER THE PLAINS BUILDS TO THE
EAST...A BROAD WAA PATTERN WILL DEVELOP OVER THE UPPER MS VALLEY AND
WRN GREAT LAKES. 295-305K ISENTRPOPIC ASCENT AHEAD OF A TROUGH
MOVING TOWARD MN WILL BRING INCREASING HIGH CLOUDS ACROSS UPPER MI
DURING THE AFTERNOON. THE INITIAL DRY LOW LEVELS AHEAD OF THE BAND
OF MOISTURE/ASCENT WILL LIMIT EASTWARD PROGRESSION OF THE LIGHT PCPN
BAND TO THE FAR WEST DURING THE LATE AFTERNOON WHERE ONLY SLIGHT
CHANCE POPS WERE INCLUDED.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 157 PM EDT SUN MAY 12 2013
SLY FLOW WILL DOMINATE BETWEEN A SFC RIDGE OVER THE ERN CWA AND A
TROUGH OVER THE MN/ND/SD BORDERS AT 00Z TUE. WAA AND ASSOCIATED THIN
BAND OF LIGHT SHOWERS WILL BE OVER THE WRN CWA. COVERAGE OF THESE
RAIN SHOWERS WILL BE LIMITED BY LIMITED MOISTURE...SO WILL KEEP POPS
ON THE LOWER SIDE SIMILAR TO LAST FORECAST. THE PRECIP MOVES TO THE
FAR ERN CWA BY 12Z TUE.
BY 00Z WED...A SHORTWAVE TROUGH AND SFC LOW WILL MOVE TO SRN
MANITOBA...BRINGING A WARM FRONT INTO THE CWA AND A COLD FRONT TO
CENTRAL MN. BY THIS TIME...850MB TEMPS WILL HAVE INCREASED TO AROUND
16C OVER THE WRN CWA AND 9C OVER THE ERN CWA /14C AND 11C WARMER
THAN 24 HOURS BEFORE...RESPECTIVELY/. THE WARM FRONT WILL MOVE
THROUGH THE CWA FOLLOWED SHORTLY AFTER BY THE COLD FRONT WED NIGHT
INTO EARLY WED. WHILE THUNDERSTORMS APPEAR LIKELY GIVEN INSTABILITY
AND STEEP LAPSE RATES...THERE IS SOME UNCERTAINTY WITH CONVECTIVE
STRENGTH. MODEL FORECAST SOUNDINGS INDICATE POTENTIAL FOR OVER
1000J/KG OF ELEVATED CAPE...BUT MODELS SHORT THE DRY SLOT ROTATING
THROUGH AROUND THE SAME TIME AS THE SHORTWAVE...BRINGING AN ELEVATED
MIXED LAYER THAT LEADS TO 100-200J/KG OF CIN. WHETHER THE COLD FRONT
CAN LIFT PARCELS THROUGH THE DRY LAYER AND THE EXACT TIMING OF THE
DRYER AIR REALLY LOWERS CONFIDENCE IN STRONGER THUNDERSTORMS.
ALSO...MODELS NOW AGREE FAIRLY WELL ON TIMING OF THE SYSTEM...BUT
VARY MORE SIGNIFICANTLY ON HOW FAR N OR S TO BRING THE
SYSTEM...WHICH IMPACTS POTENTIAL FORCING FOR ASCENT AND THE STRENGTH
OF THE LOW LEVEL JET. PRECIP DOES APPEAR LIKELY ENOUGH WED NIGHT TO
GO WITH LIKELY POPS /AT LEAST OVER THE NRN AND ERN CWA/...AND
THUNDER ALSO SEEMS LIKE A GOOD BET IN MOST LOCATIONS THAT RECEIVE
RAIN. DEFINITELY NOT SURE ON SEVERE POTENTIAL YET...BUT THERE IS
SOME INDICATION THAT ISOLATED SEVERE WX MAY BE POSSIBLE.
EVEN THOUGH 850MB TEMPS ARE COOLER DURING THE DAY WED THAN
TUE...GOOD MIXING AND SUNSHINE BEHIND THE COLD FRONT WILL LEAD TO
WARMER HIGH TEMPS AND LOWER RH VALUES...COMBINED WITH BREEZY WLY
WINDS. EXPECT HIGHS IN THE 70S INLAND...WITH AROUND 60 EXPECTED
CLOSER TO LAKE SUPERIOR. WILL CONTINUE TREND FROM PREVIOUS SHIFT OF
LOWERING DEW PTS LOWER GIVEN GOOD MIXING AND DRY AIRMASS BEHIND THE
FRONT...LEADING TO MIN RH VALUES IN THE 25-30 PERCENT /OR LOWER/
RANGE OVER INTERIOR CENTRAL AND WEST UPPER MI. INCREASED WINDS ON WED
TO GUSTS TO 30KTS OVER THE WRN CWA /COULD BE HIGHER IF NAM
VERIFIES...BUT IT IS ON THE STRONGER SIDE/. IT IS WORTH NOTING THAT
THE WARMEST TEMPS...LOWEST RH AND HIGHEST WINDS ARE EXPECTED OVER
THE INTERIOR WRN CWA...WHERE THE CHANCES FOR SIGNIFICANT PRECIP TUE
NIGHT ARE THE LOWEST. WILL NEED TO CONTINUE TO MONITOR CONDITIONS
FOR WED...BUT MAY SEE CRITICAL FIRE WEATHER CONDITIONS OVER AT LEAST
PORTIONS OF UPPER MI.
HIGH TEMPS WILL BE A A DEGREE OR TWO COOLER THU...BUT STILL EXPECT
70S INLAND AND AROUND 60 NEAR LAKE SUPERIOR. MIN RH VALUES LOOK TO
BE SIMILAR TO WED ON THE LOW END OF THE COMFORT SCALE FOR FIRE
WX...BUT WINDS WILL BE MUCH LIGHTER AS BROAD HIGH PRESSURE SETTLES
OVER THE REGION.
FOR FRI THROUGH SUN...JUST LOADED A CONSENSUS OF MODEL GUIDANCE DUE
TO INCREASED UNCERTAINTY AND GREATER FOCUS ON FORECAST TUE-THU.
OVERALL...EXPECT TEMPS AROUND SEASONAL NORMALS /A REGULAR SEASONAL
NORMAL...NOT THIS SEASONS NORMAL/ WITH HIGHS IN THE 60S TO LOW 70S.
PRECIP WILL BE POSSIBLE AS FRONTAL ZONES WILL BE NEARBY...BUT
GETTING TOO SPECIFIC AT THIS POINT WOULD BE FUTILE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 134 PM EDT SUN MAY 12 2013
AS A RIDGE AND DRIER AIR MOVES INTO THE REGION FROM THE WEST THIS
AFTERNOON...ANY LINGERING CIGS AT CMX/SAW WILL GIVE WAY TO SCT CLOUDS BY
MID TO LATE AFTERNOON. SO...MVFR CIGS AT KSAW WILL BE LAST TO SCATTER
OUT. CLEAR SKIES WILL THEN PREVAIL THIS EVENING THROUGH MON MORNING.
IT WILL REMAIN BLUSTERY AT CMX/SAW THROUGH THIS AFTERNOON WITH NW
GUSTS TO AROUND 30 MPH.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 404 PM EDT SUN MAY 12 2013
GALES WILL SUBSIDE BY EARLY EVENING AND WINDS OVER THE EAST WILL
DROP BELOW 20 KNOTS OVERNIGHT AS A RIDGE BUILDS INTO THE REGION
WINDS WILL INCREASE OUT OF THE S/SE TO 25 KTS MON NIGHT THROUGH TUE
NIGHT AHEAD OF A LOW PRESSURE SYSTEM MOVING NORTH OF LAKE SUPERIOR
ON WED. A WARM FRONT SLIDING ACROSS LAKE SUPERIOR TUESDAY NIGHT AHEAD
OF THE LOW MAY RESULT IN A FEW STRONGER THUNDERSTORMS. LIGHTNING AND
HEAVY DOWNPOURS WOULD BE THE PRIMARY HAZARDS. EXPECT WINDS TO SHIFT
WESTERLY ON WEDNESDAY BEHIND THE COLD FRONT. POSSIBLE THAT GUSTS
COULD REACH 30 KTS. LIGHTER WINDS ARE EXPECTED AGAIN LATE IN THE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR LSZ249>251-266-267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
158 PM EDT SUN MAY 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 549 AM EDT SUN MAY 12 2013
WV IMAGERY AND RUC ANALYSIS SHOW STRONG SHORTWAVE/CLOSED LOW SYSTEM
NE OF LAKE SUPERIOR EARLY THIS MORNING. ENHANCEMENT ON THE BACK EDGE
OF THIS SYSTEM COMBINED WITH COLD ADVECTION IN ITS WAKE...HELPED
PRODUCE SOME MODERATE SNOW ACCUMULATION FROM NEGAUNEE/ISHPEMING EAST
THROUGH ALGER AND NRN SCHOOLCRAFT COUNTIES EARLIER THIS MORNING.
HOWEVER...IN THE PAST HR OR TWO RADAR RETURNS HAVE DIMINISHED
DRAMATICALLY IN AREAL EXTENT AND INTENSITY. HERE AT NWS MQT...SNOW
HAS DIMINISHED TO FLURRIES AND EXPECT THIS IS THE CASE AT MANY
LOCATIONS BASED ON RADAR RETURNS. LATEST VAD WIND PROFILE FROM MQT
RADAR ALSO SHOWS INDICATION OF SHARP LOWERING OF SUBSIDENCE
INVERSION FROM 9-10 KFT TO 6 KFT IN PAST HR WHICH IS ALSO CONSISTENT
WITH DIMINISHED RADAR RETURNS.
TODAY...GIVEN RECENT DIMINISHING RADAR TRENDS AND FACT THAT MODELS
SHOW BEST Q-VECT CONV FOR LAKE ENHANCEMENT TO BE MOVING EAST WITH
TIME THIS MORNING...HAVE DECIDED TO CANCEL THE WINTER WEATHER
ADVISORIES FOR NORTH CENTRAL COUNTIES. MOST PLACES FROM MQT COUNTY
EASTWARD WILL BE HARD PRESSED TO SEE MORE THAN HALF AN INCH OF
ADDITIONAL SNOW ACCUMULATION WITH ONLY A FEW LINGERING FLURRIES
NOTED TO THE WEST. UPDATED POPS TO REFLECT SHARP DIMINISHING TREND
TO PCPN THIS MORNING. LINGERING CYCLONIC FLOW AND -10C 8H TEMPS
MOVING ACROSS LAKE SUPERIOR COULD STILL SUPPORT PLENTY OF LAKE
STRATOCU CLOUDS THROUGH THE MORNING HRS...ESPECIALLY FOR
EASTERN COUNTIES DOWNWIND OF LONGER NNW FETCH ACROSS ERN LAKE
SUPERIOR. SHARP SUBSIDENCE/DRYING WITH A TRANSITION TO MORE NEUTRAL
OR ANTICYCLONIC FLOW FROM THE WEST BY AFTERNOON SHOULD ALLOW FOR
CLEARING SKIES FROM THE WEST THIS AFTERNOON. FAIRLY TIGHT NW PRES
GRAD ON THE BACKSIDE OF EXITING LOW WILL KEEP WINDS GUSTING TO NEAR
35 MPH OVER THE ERN HALF COUNTIES ESPECIALLY NEAR LAKE SUPERIOR.
OTHERWISE...UNSEASONABLY COLD CONDITIONS WILL CONTINUE WITH HIGHS
RANGING FROM AROUND 40 NORTH AND EAST TO MID 40S SOUTH CENTRAL.
TONIGHT...GIVEN RELATIVELY COLD HIGH TEMPS EXPECTED TODAY...SFC
RIDGING AND ASSOCIATED CLEARING BUILDING IN FROM THE W SHOULD ALLOW
SFC TEMPS TO PLUMMET TONIGHT TO RECORD OR NEAR RECORD LOW READINGS
ESPECIALLY OVER THE WRN CWA. LEANED ON THE LOWER END OF MODEL
GUIDANCE FOR MIN TEMPS WITH EXPECTED READINGS IN THE MID TO UPPER
TEENS OVER THE TYPICALLY COLD WRN INTERIOR LOCATIONS AND LOWER TO
MID 20S ACROSS THE REST OF THE INTERIOR CWA. TEMPS WILL STAY A BIT
WARMER NEAR THE GREAT LAKES...GENERALLY IN THE UPPER 20S.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 157 PM EDT SUN MAY 12 2013
SLY FLOW WILL DOMINATE BETWEEN A SFC RIDGE OVER THE ERN CWA AND A
TROUGH OVER THE MN/ND/SD BORDERS AT 00Z TUE. WAA AND ASSOCIATED THIN
BAND OF LIGHT SHOWERS WILL BE OVER THE WRN CWA. COVERAGE OF THESE
RAIN SHOWERS WILL BE LIMITED BY LIMITED MOISTURE...SO WILL KEEP POPS
ON THE LOWER SIDE SIMILAR TO LAST FORECAST. THE PRECIP MOVES TO THE
FAR ERN CWA BY 12Z TUE.
BY 00Z WED...A SHORTWAVE TROUGH AND SFC LOW WILL MOVE TO SRN
MANITOBA...BRINGING A WARM FRONT INTO THE CWA AND A COLD FRONT TO
CENTRAL MN. BY THIS TIME...850MB TEMPS WILL HAVE INCREASED TO AROUND
16C OVER THE WRN CWA AND 9C OVER THE ERN CWA /14C AND 11C WARMER
THAN 24 HOURS BEFORE...RESPECTIVELY/. THE WARM FRONT WILL MOVE
THROUGH THE CWA FOLLOWED SHORTLY AFTER BY THE COLD FRONT WED NIGHT
INTO EARLY WED. WHILE THUNDERSTORMS APPEAR LIKELY GIVEN INSTABILITY
AND STEEP LAPSE RATES...THERE IS SOME UNCERTAINTY WITH CONVECTIVE
STRENGTH. MODEL FORECAST SOUNDINGS INDICATE POTENTIAL FOR OVER
1000J/KG OF ELEVATED CAPE...BUT MODELS SHORT THE DRY SLOT ROTATING
THROUGH AROUND THE SAME TIME AS THE SHORTWAVE...BRINGING AN ELEVATED
MIXED LAYER THAT LEADS TO 100-200J/KG OF CIN. WHETHER THE COLD FRONT
CAN LIFT PARCELS THROUGH THE DRY LAYER AND THE EXACT TIMING OF THE
DRYER AIR REALLY LOWERS CONFIDENCE IN STRONGER THUNDERSTORMS.
ALSO...MODELS NOW AGREE FAIRLY WELL ON TIMING OF THE SYSTEM...BUT
VARY MORE SIGNIFICANTLY ON HOW FAR N OR S TO BRING THE
SYSTEM...WHICH IMPACTS POTENTIAL FORCING FOR ASCENT AND THE STRENGTH
OF THE LOW LEVEL JET. PRECIP DOES APPEAR LIKELY ENOUGH WED NIGHT TO
GO WITH LIKELY POPS /AT LEAST OVER THE NRN AND ERN CWA/...AND
THUNDER ALSO SEEMS LIKE A GOOD BET IN MOST LOCATIONS THAT RECEIVE
RAIN. DEFINITELY NOT SURE ON SEVERE POTENTIAL YET...BUT THERE IS
SOME INDICATION THAT ISOLATED SEVERE WX MAY BE POSSIBLE.
EVEN THOUGH 850MB TEMPS ARE COOLER DURING THE DAY WED THAN
TUE...GOOD MIXING AND SUNSHINE BEHIND THE COLD FRONT WILL LEAD TO
WARMER HIGH TEMPS AND LOWER RH VALUES...COMBINED WITH BREEZY WLY
WINDS. EXPECT HIGHS IN THE 70S INLAND...WITH AROUND 60 EXPECTED
CLOSER TO LAKE SUPERIOR. WILL CONTINUE TREND FROM PREVIOUS SHIFT OF
LOWERING DEW PTS LOWER GIVEN GOOD MIXING AND DRY AIRMASS BEHIND THE
FRONT...LEADING TO MIN RH VALUES IN THE 25-30 PERCENT /OR LOWER/
RANGE OVER INTERIOR CENTRAL AND WEST UPPER MI. INCREASED WINDS ON WED
TO GUSTS TO 30KTS OVER THE WRN CWA /COULD BE HIGHER IF NAM
VERIFIES...BUT IT IS ON THE STRONGER SIDE/. IT IS WORTH NOTING THAT
THE WARMEST TEMPS...LOWEST RH AND HIGHEST WINDS ARE EXPECTED OVER
THE INTERIOR WRN CWA...WHERE THE CHANCES FOR SIGNIFICANT PRECIP TUE
NIGHT ARE THE LOWEST. WILL NEED TO CONTINUE TO MONITOR CONDITIONS
FOR WED...BUT MAY SEE CRITICAL FIRE WEATHER CONDITIONS OVER AT LEAST
PORTIONS OF UPPER MI.
HIGH TEMPS WILL BE A A DEGREE OR TWO COOLER THU...BUT STILL EXPECT
70S INLAND AND AROUND 60 NEAR LAKE SUPERIOR. MIN RH VALUES LOOK TO
BE SIMILAR TO WED ON THE LOW END OF THE COMFORT SCALE FOR FIRE
WX...BUT WINDS WILL BE MUCH LIGHTER AS BROAD HIGH PRESSURE SETTLES
OVER THE REGION.
FOR FRI THROUGH SUN...JUST LOADED A CONSENSUS OF MODEL GUIDANCE DUE
TO INCREASED UNCERTAINTY AND GREATER FOCUS ON FORECAST TUE-THU.
OVERALL...EXPECT TEMPS AROUND SEASONAL NORMALS /A REGULAR SEASONAL
NORMAL...NOT THIS SEASONS NORMAL/ WITH HIGHS IN THE 60S TO LOW 70S.
PRECIP WILL BE POSSIBLE AS FRONTAL ZONES WILL BE NEARBY...BUT
GETTING TOO SPECIFIC AT THIS POINT WOULD BE FUTILE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 134 PM EDT SUN MAY 12 2013
AS A RIDGE AND DRIER AIR MOVES INTO THE REGION FROM THE WEST THIS
AFTERNOON...ANY LINGERING CIGS AT CMX/SAW WILL GIVE WAY TO SCT CLOUDS BY
MID TO LATE AFTERNOON. SO...MVFR CIGS AT KSAW WILL BE LAST TO SCATTER
OUT. CLEAR SKIES WILL THEN PREVAIL THIS EVENING THROUGH MON MORNING.
IT WILL REMAIN BLUSTERY AT CMX/SAW THROUGH THIS AFTERNOON WITH NW
GUSTS TO AROUND 30 MPH.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 549 AM EDT SUN MAY 12 2013
GALES CONTINUE OVER EASTERN SECTIONS INTO THIS AFTN THEN WINDS
DIMINISH BY TONIGHT AS HIGH PRESSURE RIDGE MOVES ACROSS. WINDS
INCREASE OUT OF THE S/SE TO 25 KTS MON NIGHT THROUGH TUE NIGHT
AHEAD OF A LOW PRESSURE SYSTEM MOVING NORTH OF LAKE SUPERIOR ON
WED. WARM FRONT SLIDING ACROSS LK SUPERIOR TUESDAY NIGHT AHEAD OF
THE LOW MAY RESULT IN A FEW STRONGER THUNDERSTORMS. LIGHTNING AND
HEAVY DOWNPOURS WOULD BE THE PRIMARY HAZARDS. EXPECT WINDS TO SHIFT
WESTERLY ON WEDNESDAY BEHIND THE COLD FRONT. POSSIBLE THAT GUSTS
COULD REACH 30 KTS. LIGHTER WINDS AGAIN LATE IN THE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR LSZ249>251-266-267.
GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR LSZ243>245-264-
265.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
136 PM EDT SUN MAY 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 549 AM EDT SUN MAY 12 2013
WV IMAGERY AND RUC ANALYSIS SHOW STRONG SHORTWAVE/CLOSED LOW SYSTEM
NE OF LAKE SUPERIOR EARLY THIS MORNING. ENHANCEMENT ON THE BACK EDGE
OF THIS SYSTEM COMBINED WITH COLD ADVECTION IN ITS WAKE...HELPED
PRODUCE SOME MODERATE SNOW ACCUMULATION FROM NEGAUNEE/ISHPEMING EAST
THROUGH ALGER AND NRN SCHOOLCRAFT COUNTIES EARLIER THIS MORNING.
HOWEVER...IN THE PAST HR OR TWO RADAR RETURNS HAVE DIMINISHED
DRAMATICALLY IN AREAL EXTENT AND INTENSITY. HERE AT NWS MQT...SNOW
HAS DIMINISHED TO FLURRIES AND EXPECT THIS IS THE CASE AT MANY
LOCATIONS BASED ON RADAR RETURNS. LATEST VAD WIND PROFILE FROM MQT
RADAR ALSO SHOWS INDICATION OF SHARP LOWERING OF SUBSIDENCE
INVERSION FROM 9-10 KFT TO 6 KFT IN PAST HR WHICH IS ALSO CONSISTENT
WITH DIMINISHED RADAR RETURNS.
TODAY...GIVEN RECENT DIMINISHING RADAR TRENDS AND FACT THAT MODELS
SHOW BEST Q-VECT CONV FOR LAKE ENHANCEMENT TO BE MOVING EAST WITH
TIME THIS MORNING...HAVE DECIDED TO CANCEL THE WINTER WEATHER
ADVISORIES FOR NORTH CENTRAL COUNTIES. MOST PLACES FROM MQT COUNTY
EASTWARD WILL BE HARD PRESSED TO SEE MORE THAN HALF AN INCH OF
ADDITIONAL SNOW ACCUMULATION WITH ONLY A FEW LINGERING FLURRIES
NOTED TO THE WEST. UPDATED POPS TO REFLECT SHARP DIMINISHING TREND
TO PCPN THIS MORNING. LINGERING CYCLONIC FLOW AND -10C 8H TEMPS
MOVING ACROSS LAKE SUPERIOR COULD STILL SUPPORT PLENTY OF LAKE
STRATOCU CLOUDS THROUGH THE MORNING HRS...ESPECIALLY FOR
EASTERN COUNTIES DOWNWIND OF LONGER NNW FETCH ACROSS ERN LAKE
SUPERIOR. SHARP SUBSIDENCE/DRYING WITH A TRANSITION TO MORE NEUTRAL
OR ANTICYCLONIC FLOW FROM THE WEST BY AFTERNOON SHOULD ALLOW FOR
CLEARING SKIES FROM THE WEST THIS AFTERNOON. FAIRLY TIGHT NW PRES
GRAD ON THE BACKSIDE OF EXITING LOW WILL KEEP WINDS GUSTING TO NEAR
35 MPH OVER THE ERN HALF COUNTIES ESPECIALLY NEAR LAKE SUPERIOR.
OTHERWISE...UNSEASONABLY COLD CONDITIONS WILL CONTINUE WITH HIGHS
RANGING FROM AROUND 40 NORTH AND EAST TO MID 40S SOUTH CENTRAL.
TONIGHT...GIVEN RELATIVELY COLD HIGH TEMPS EXPECTED TODAY...SFC
RIDGING AND ASSOCIATED CLEARING BUILDING IN FROM THE W SHOULD ALLOW
SFC TEMPS TO PLUMMET TONIGHT TO RECORD OR NEAR RECORD LOW READINGS
ESPECIALLY OVER THE WRN CWA. LEANED ON THE LOWER END OF MODEL
GUIDANCE FOR MIN TEMPS WITH EXPECTED READINGS IN THE MID TO UPPER
TEENS OVER THE TYPICALLY COLD WRN INTERIOR LOCATIONS AND LOWER TO
MID 20S ACROSS THE REST OF THE INTERIOR CWA. TEMPS WILL STAY A BIT
WARMER NEAR THE GREAT LAKES...GENERALLY IN THE UPPER 20S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 549 AM EDT SUN MAY 12 2013
UPPER PATTERN FEATURING WESTERN CONUS RIDGING AND EASTERN CONUS
TROUGHING BECOMES MORE ZONAL THROUGH THE WEEK...RESULTING IN
WARMING TREND FOR UPPER GREAT LAKES. AS THE UPPER PATTERN BECOMES
MORE ZONAL EXPECT SFC LOW AND FRONTAL BOUNDARIES TO MOVE FROM
CENTRAL CANADA ACROSS THE GREAT LAKES TUESDAY THROUGH THURSDAY. BEST
CHANCE OF RAIN IN THIS PATTERN SHOULD BE LATER TUESDAY THROUGH
TUESDAY NIGHT AS WARM FRONT SLIDES ACROSS UPPER GREAT LAKES. EXTENT
OF COOLING BEHIND COLD FRONT WEDNESDAY INTO THURSDAY UNCERTAIN. EVEN
THE MODELS THAT ARE SHOWING THE MOST EMPHATIC COOLING /GFS AND NAM/
SHOW NOTHING TO THE EXTENT OF CURRENT COOLDOWN THAT IS CURRENTLY
OCCURRING. SO...BEYOND THIS TASTE OF WINTER AFFECTING THE REGION
THIS MORNING...EXPECT EXTENDED TO HOLD ONLY LIQUID PRECIPITATION.
HIGH PRESSURE BEGINS THE EXTENDED PERIOD OVER WESTERN GREAT LAKES.
RIDGE AXIS HEADS ACROSS REST OF GREAT LAKES BY MONDAY NIGHT ALLOWING
WARM AIR ADVECTION/RETURN FLOW TO DEVELOP. THROUGH DAY 2 LEANED ON
THE NAM/GFS SOUNDINGS TO TRY TO GAGE PRECIP CHANCES. MOISTURE
ADVECTION FOCUSED MAINLY ALOFT H85-H7 MONDAY NIGHT. SOME LGT SHOWERS
SEEM LIKELY IN MAX ADVECTION AREA MOVING WEST TO EAST ACROSS CWA.
ONCE MID-LEVEL MOISTURE/LIFT IS STRIPPED AWAY...SHALLOW MOISTURE
MAINLY BLO H9 IS ALL THAT IS LEFT ON TUESDAY. HINTS FROM MODELS THAT
MOISTURE MAY MIX OUT BY AFTN. LOWERED POPS BASED ON LIMITED MOISTURE
INTO TUESDAY AFTN. NEXT SURGE OF MOISTURE/TEMPERATURE ADVECTION AND
ELEVATED INSTABILITY COULD BRING SHOWERS/TSRA OVER GENERALLY WESTERN
CWA LATE TUESDAY AFTN. SE WINDS AHEAD OF WARM FRONT WITH MORE
INFLUENCE OFF LK MICHIGAN FOR MUCH OF CWA SHOULD KEEP TEMPS FROM
GETTING TOO WARM EVEN WITH ONLY SCT CLOUDS BY AFTN. WARMEST READINGS
INTO THE 70S INLAND WEST AND SOUTHWEST CWA WITH LESS LAKE MODIFIED
COOLER AIR. UPR 50S TO UPR 60S ELSEWHERE.
WARM FRONT PASSAGE/MAXIMUM LOW-LEVEL MOISTURE AND TEMP ADVECTION
STILL ON TRACK FOR TUESDAY NIGHT. HAS LOOKED THIS WAY FOR A WHILE
NOW. STILL THINKING THIS IS THE BEST CHANCE FOR SHOWERS AND TSRA
ACROSS CWA...BUT STILL MAY NOT BE WIDESPREAD EVENT FOR ALL CWA. SOME
DIFFERENCE HOW FAR SOUTH SHORTWAVE TROUGH/MID-LEVEL HEIGHT FALLS DIP
INTO UPR LAKES AND THIS IMPACTS SOUTHERN EXTENT OF PRIMARY UPPER
LEVEL JET AND ASSOCIATED DIVERGENCE TO ENHANCE PRECIP. PLACED LIKELY
POPS OVER NORTH AND EAST AND KEPT POPS SCATTERED FARTHER SOUTH. GIVEN
H85 DWPNTS OVER +12C AND 1-6KM MUCAPES OVER 1000J/KG AND SINCE AXIS
OF 925-850MB WIND MAX IS OVERHEAD...SHRA AND TSRA CANNOT BE COUNTED
OUT ANYWHERE THOUGH. STRONGST WINDS ALOFT ARE MORE OVER LAKE SUPERIOR
AND NORTH INTO ONTARIO SO THINK THIS IS WHERE BETTER CHANCE OF
STRONGER STORMS WOULD BE LOCATED. SEEMS THAT LIGHTNING AND HEAVY
DOWNPOURS WILL BE THE PRIMARY HAZARDS. THOUGH WBZERO HEIGHTS
11-12KFT IS ON THE HIGHER SIDE TO SEE LARGE HAIL...IT IS POSSIBLE
GIVEN STRONGER SHEAR AND H7-H5 LAPSE RATES OVER 7C/KM.
GOOD AGREEMENT THAT AREA OF ENHANCED PRECIP SWIFTLY CROSSES THE AREA
LATER TUESDAY NIGHT WITH COLD FRONTAL PASSAGE NOT TOO FAR BEHIND ON
WEDNESDAY MORNING. SUBSTANTIAL CLEARING IN THE OFFING ON WEDNESDAY
IN WAKE OF THE FRONT. 00Z ECMWF TRENDED SLIGHTLY TOWARD COLDER GFS
IDEA FOR H85 TEMPS IN WAKE OF COLD FRONT...BUT EVEN SO...EXPECT
SUNSHINE AND DEEP MIXING TO OFFSET THIS AND LEAD TO MAX TEMPS INTO
THE 70S SOUTHWEST AND SOUTH CENTRAL. READINGS IN THE 60S CLOSER TO
LK SUPERIOR. WINDS MAY END UP STRONGER THAN WHAT CONSENSUS SHOWED
BUT LEFT THEM ALONE FOR NOW. DID GO WITH LOWER BIAS CORRECTED MOS
DWPNTS IN THE AFTN GIVEN THE DEEP MIXING.
THURSDAY AND FRIDAY....A BIT UNSETTLED POTENTIALLY. PRIMARY SFC
FRONTAL BOUNDARY WILL REMAIN SOUTH OF UPR MICHIGAN. YET SINCE THE
AREA IS ON SOUTHERN EDGE OF TROUGH OVR CANADA...THE JET STREAM IS
TOO CLOSE BY TO NOT HAVE AT LEAST SLIGHT CHANCE POPS. MODELS HAVE
SHOWN SOME QPF FROM TIME TO TIME...ESPECIALLY LATER FRIDAY AND
FRIDAY NIGHT AS SECONDARY SFC TROUGH DIPS SOUTH ACROSS THE UPPER
GREAT LAKES.
BY NEXT WEEKEND THE MAIN ISSUE WILL BE INFLUENCE OF DEVELOPING LOW
PRESSURE OVER PLAINS. 12Z ECMWF FARTHER TO THE EAST...WHILE GFS AND
WPC HAND DRAWN PROGS KEEP LOW SHUNTED MORE OVER THE PLAINS AND SFC
RIDGE OVER THE UPR LAKES. CONSENSUS OF MODELS WHICH HAS DOUBLE
WEIGHTING OF THE TYPICALLY BETTER PERFORMING ECMWF SHOWS INCREASING
CHANCES OF SHOWERS BY LATER IN THE WEEKEND. TEMPS TO END THE
EXTENDED WILL BE AROUND NORMAL...THOUGH MAY REMAIN SLIGHTLY BELOW
NORMAL ALONG LK SUPERIOR DUE TO PREVAILING NORTHERLY SFC WINDS.
EVEN IF IT DOES END UP BELOW NORMAL...NO SNOW IS IN THE
FORECAST...WHICH IS CERTAINLY WELCOME NEWS FOR THOSE WEARY OF THE
WINTER THAT HAS BEEN RELUCTANT TO END.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 134 PM EDT SUN MAY 12 2013
AS A RIDGE AND DRIER AIR MOVES INTO THE REGION FROM THE WEST THIS
AFTERNOON...ANY LINGERING CIGS AT CMX/SAW WILL GIVE WAY TO SCT CLOUDS BY
MID TO LATE AFTERNOON. SO...MVFR CIGS AT KSAW WILL BE LAST TO SCATTER
OUT. CLEAR SKIES WILL THEN PREVAIL THIS EVENING THROUGH MON MORNING.
IT WILL REMAIN BLUSTERY AT CMX/SAW THROUGH THIS AFTERNOON WITH NW
GUSTS TO AROUND 30 MPH.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 549 AM EDT SUN MAY 12 2013
GALES CONTINUE OVER EASTERN SECTIONS INTO THIS AFTN THEN WINDS
DIMINISH BY TONIGHT AS HIGH PRESSURE RIDGE MOVES ACROSS. WINDS
INCREASE OUT OF THE S/SE TO 25 KTS MON NIGHT THROUGH TUE NIGHT
AHEAD OF A LOW PRESSURE SYSTEM MOVING NORTH OF LAKE SUPERIOR ON
WED. WARM FRONT SLIDING ACROSS LK SUPERIOR TUESDAY NIGHT AHEAD OF
THE LOW MAY RESULT IN A FEW STRONGER THUNDERSTORMS. LIGHTNING AND
HEAVY DOWNPOURS WOULD BE THE PRIMARY HAZARDS. EXPECT WINDS TO SHIFT
WESTERLY ON WEDNESDAY BEHIND THE COLD FRONT. POSSIBLE THAT GUSTS
COULD REACH 30 KTS. LIGHTER WINDS AGAIN LATE IN THE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR LSZ249>251-266-267.
GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR LSZ243>245-264-
265.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...JLA
AVIATION...JLB
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
727 AM EDT SUN MAY 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 549 AM EDT SUN MAY 12 2013
WV IMAGERY AND RUC ANALYSIS SHOW STRONG SHORTWAVE/CLOSED LOW SYSTEM
NE OF LAKE SUPERIOR EARLY THIS MORNING. ENHANCEMENT ON THE BACK EDGE
OF THIS SYSTEM COMBINED WITH COLD ADVECTION IN ITS WAKE...HELPED
PRODUCE SOME MODERATE SNOW ACCUMULATION FROM NEGAUNEE/ISHPEMING EAST
THROUGH ALGER AND NRN SCHOOLCRAFT COUNTIES EARLIER THIS MORNING.
HOWEVER...IN THE PAST HR OR TWO RADAR RETURNS HAVE DIMINISHED
DRAMATICALLY IN AREAL EXTENT AND INTENSITY. HERE AT NWS MQT...SNOW
HAS DIMINISHED TO FLURRIES AND EXPECT THIS IS THE CASE AT MANY
LOCATIONS BASED ON RADAR RETURNS. LATEST VAD WIND PROFILE FROM MQT
RADAR ALSO SHOWS INDICATION OF SHARP LOWERING OF SUBSIDENCE
INVERSION FROM 9-10 KFT TO 6 KFT IN PAST HR WHICH IS ALSO CONSISTENT
WITH DIMINISHED RADAR RETURNS.
TODAY...GIVEN RECENT DIMINISHING RADAR TRENDS AND FACT THAT MODELS
SHOW BEST Q-VECT CONV FOR LAKE ENHANCEMENT TO BE MOVING EAST WITH
TIME THIS MORNING...HAVE DECIDED TO CANCEL THE WINTER WEATHER
ADVISORIES FOR NORTH CENTRAL COUNTIES. MOST PLACES FROM MQT COUNTY
EASTWARD WILL BE HARD PRESSED TO SEE MORE THAN HALF AN INCH OF
ADDITIONAL SNOW ACCUMULATION WITH ONLY A FEW LINGERING FLURRIES
NOTED TO THE WEST. UPDATED POPS TO REFLECT SHARP DIMINISHING TREND
TO PCPN THIS MORNING. LINGERING CYCLONIC FLOW AND -10C 8H TEMPS
MOVING ACROSS LAKE SUPERIOR COULD STILL SUPPORT PLENTY OF LAKE
STRATOCU CLOUDS THROUGH THE MORNING HRS...ESPECIALLY FOR
EASTERN COUNTIES DOWNWIND OF LONGER NNW FETCH ACROSS ERN LAKE
SUPERIOR. SHARP SUBSIDENCE/DRYING WITH A TRANSITION TO MORE NEUTRAL
OR ANTICYCLONIC FLOW FROM THE WEST BY AFTERNOON SHOULD ALLOW FOR
CLEARING SKIES FROM THE WEST THIS AFTERNOON. FAIRLY TIGHT NW PRES
GRAD ON THE BACKSIDE OF EXITING LOW WILL KEEP WINDS GUSTING TO NEAR
35 MPH OVER THE ERN HALF COUNTIES ESPECIALLY NEAR LAKE SUPERIOR.
OTHERWISE...UNSEASONABLY COLD CONDITIONS WILL CONTINUE WITH HIGHS
RANGING FROM AROUND 40 NORTH AND EAST TO MID 40S SOUTH CENTRAL.
TONIGHT...GIVEN RELATIVELY COLD HIGH TEMPS EXPECTED TODAY...SFC
RIDGING AND ASSOCIATED CLEARING BUILDING IN FROM THE W SHOULD ALLOW
SFC TEMPS TO PLUMMET TONIGHT TO RECORD OR NEAR RECORD LOW READINGS
ESPECIALLY OVER THE WRN CWA. LEANED ON THE LOWER END OF MODEL
GUIDANCE FOR MIN TEMPS WITH EXPECTED READINGS IN THE MID TO UPPER
TEENS OVER THE TYPICALLY COLD WRN INTERIOR LOCATIONS AND LOWER TO
MID 20S ACROSS THE REST OF THE INTERIOR CWA. TEMPS WILL STAY A BIT
WARMER NEAR THE GREAT LAKES...GENERALLY IN THE UPPER 20S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 549 AM EDT SUN MAY 12 2013
UPPER PATTERN FEATURING WESTERN CONUS RIDGING AND EASTERN CONUS
TROUGHING BECOMES MORE ZONAL THROUGH THE WEEK...RESULTING IN
WARMING TREND FOR UPPER GREAT LAKES. AS THE UPPER PATTERN BECOMES
MORE ZONAL EXPECT SFC LOW AND FRONTAL BOUNDARIES TO MOVE FROM
CENTRAL CANADA ACROSS THE GREAT LAKES TUESDAY THROUGH THURSDAY. BEST
CHANCE OF RAIN IN THIS PATTERN SHOULD BE LATER TUESDAY THROUGH
TUESDAY NIGHT AS WARM FRONT SLIDES ACROSS UPPER GREAT LAKES. EXTENT
OF COOLING BEHIND COLD FRONT WEDNESDAY INTO THURSDAY UNCERTAIN. EVEN
THE MODELS THAT ARE SHOWING THE MOST EMPHATIC COOLING /GFS AND NAM/
SHOW NOTHING TO THE EXTENT OF CURRENT COOLDOWN THAT IS CURRENTLY
OCCURRING. SO...BEYOND THIS TASTE OF WINTER AFFECTING THE REGION
THIS MORNING...EXPECT EXTENDED TO HOLD ONLY LIQUID PRECIPITATION.
HIGH PRESSURE BEGINS THE EXTENDED PERIOD OVER WESTERN GREAT LAKES.
RIDGE AXIS HEADS ACROSS REST OF GREAT LAKES BY MONDAY NIGHT ALLOWING
WARM AIR ADVECTION/RETURN FLOW TO DEVELOP. THROUGH DAY 2 LEANED ON
THE NAM/GFS SOUNDINGS TO TRY TO GAGE PRECIP CHANCES. MOISTURE
ADVECTION FOCUSED MAINLY ALOFT H85-H7 MONDAY NIGHT. SOME LGT SHOWERS
SEEM LIKELY IN MAX ADVECTION AREA MOVING WEST TO EAST ACROSS CWA.
ONCE MID-LEVEL MOISTURE/LIFT IS STRIPPED AWAY...SHALLOW MOISTURE
MAINLY BLO H9 IS ALL THAT IS LEFT ON TUESDAY. HINTS FROM MODELS THAT
MOISTURE MAY MIX OUT BY AFTN. LOWERED POPS BASED ON LIMITED MOISTURE
INTO TUESDAY AFTN. NEXT SURGE OF MOISTURE/TEMPERATURE ADVECTION AND
ELEVATED INSTABILITY COULD BRING SHOWERS/TSRA OVER GENERALLY WESTERN
CWA LATE TUESDAY AFTN. SE WINDS AHEAD OF WARM FRONT WITH MORE
INFLUENCE OFF LK MICHIGAN FOR MUCH OF CWA SHOULD KEEP TEMPS FROM
GETTING TOO WARM EVEN WITH ONLY SCT CLOUDS BY AFTN. WARMEST READINGS
INTO THE 70S INLAND WEST AND SOUTHWEST CWA WITH LESS LAKE MODIFIED
COOLER AIR. UPR 50S TO UPR 60S ELSEWHERE.
WARM FRONT PASSAGE/MAXIMUM LOW-LEVEL MOISTURE AND TEMP ADVECTION
STILL ON TRACK FOR TUESDAY NIGHT. HAS LOOKED THIS WAY FOR A WHILE
NOW. STILL THINKING THIS IS THE BEST CHANCE FOR SHOWERS AND TSRA
ACROSS CWA...BUT STILL MAY NOT BE WIDESPREAD EVENT FOR ALL CWA. SOME
DIFFERENCE HOW FAR SOUTH SHORTWAVE TROUGH/MID-LEVEL HEIGHT FALLS DIP
INTO UPR LAKES AND THIS IMPACTS SOUTHERN EXTENT OF PRIMARY UPPER
LEVEL JET AND ASSOCIATED DIVERGENCE TO ENHANCE PRECIP. PLACED LIKELY
POPS OVER NORTH AND EAST AND KEPT POPS SCATTERED FARTHER SOUTH. GIVEN
H85 DWPNTS OVER +12C AND 1-6KM MUCAPES OVER 1000J/KG AND SINCE AXIS
OF 925-850MB WIND MAX IS OVERHEAD...SHRA AND TSRA CANNOT BE COUNTED
OUT ANYWHERE THOUGH. STRONGST WINDS ALOFT ARE MORE OVER LAKE SUPERIOR
AND NORTH INTO ONTARIO SO THINK THIS IS WHERE BETTER CHANCE OF
STRONGER STORMS WOULD BE LOCATED. SEEMS THAT LIGHTNING AND HEAVY
DOWNPOURS WILL BE THE PRIMARY HAZARDS. THOUGH WBZERO HEIGHTS
11-12KFT IS ON THE HIGHER SIDE TO SEE LARGE HAIL...IT IS POSSIBLE
GIVEN STRONGER SHEAR AND H7-H5 LAPSE RATES OVER 7C/KM.
GOOD AGREEMENT THAT AREA OF ENHANCED PRECIP SWIFTLY CROSSES THE AREA
LATER TUESDAY NIGHT WITH COLD FRONTAL PASSAGE NOT TOO FAR BEHIND ON
WEDNESDAY MORNING. SUBSTANTIAL CLEARING IN THE OFFING ON WEDNESDAY
IN WAKE OF THE FRONT. 00Z ECMWF TRENDED SLIGHTLY TOWARD COLDER GFS
IDEA FOR H85 TEMPS IN WAKE OF COLD FRONT...BUT EVEN SO...EXPECT
SUNSHINE AND DEEP MIXING TO OFFSET THIS AND LEAD TO MAX TEMPS INTO
THE 70S SOUTHWEST AND SOUTH CENTRAL. READINGS IN THE 60S CLOSER TO
LK SUPERIOR. WINDS MAY END UP STRONGER THAN WHAT CONSENSUS SHOWED
BUT LEFT THEM ALONE FOR NOW. DID GO WITH LOWER BIAS CORRECTED MOS
DWPNTS IN THE AFTN GIVEN THE DEEP MIXING.
THURSDAY AND FRIDAY....A BIT UNSETTLED POTENTIALLY. PRIMARY SFC
FRONTAL BOUNDARY WILL REMAIN SOUTH OF UPR MICHIGAN. YET SINCE THE
AREA IS ON SOUTHERN EDGE OF TROUGH OVR CANADA...THE JET STREAM IS
TOO CLOSE BY TO NOT HAVE AT LEAST SLIGHT CHANCE POPS. MODELS HAVE
SHOWN SOME QPF FROM TIME TO TIME...ESPECIALLY LATER FRIDAY AND
FRIDAY NIGHT AS SECONDARY SFC TROUGH DIPS SOUTH ACROSS THE UPPER
GREAT LAKES.
BY NEXT WEEKEND THE MAIN ISSUE WILL BE INFLUENCE OF DEVELOPING LOW
PRESSURE OVER PLAINS. 12Z ECMWF FARTHER TO THE EAST...WHILE GFS AND
WPC HAND DRAWN PROGS KEEP LOW SHUNTED MORE OVER THE PLAINS AND SFC
RIDGE OVER THE UPR LAKES. CONSENSUS OF MODELS WHICH HAS DOUBLE
WEIGHTING OF THE TYPICALLY BETTER PERFORMING ECMWF SHOWS INCREASING
CHANCES OF SHOWERS BY LATER IN THE WEEKEND. TEMPS TO END THE
EXTENDED WILL BE AROUND NORMAL...THOUGH MAY REMAIN SLIGHTLY BELOW
NORMAL ALONG LK SUPERIOR DUE TO PREVAILING NORTHERLY SFC WINDS.
EVEN IF IT DOES END UP BELOW NORMAL...NO SNOW IS IN THE
FORECAST...WHICH IS CERTAINLY WELCOME NEWS FOR THOSE WEARY OF THE
WINTER THAT HAS BEEN RELUCTANT TO END.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 721 AM EDT SUN MAY 12 2013
MVFR CONDITIONS WILL GRADUALLY IMPROVE TO VFR AT KCMX AND KSAW WITH
ADVECTION OF DRIER AIR FROM THE WEST AND WEAK DIURNAL HEATING. KIWD
SHOULD SEE VFR STRATOCU DECK SCT OUT BY LATE MORNING AS DRIER DRY
AIR WORKS IN FM WEST. NW WINDS WILL BE GUSTY TO AROUND 25 KT AT KCMX
AND KSAW THROUGH AT LEAST MID AFTERNOON. LOOK FOR WINDS TO DIE OFF
THIS EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 549 AM EDT SUN MAY 12 2013
GALES CONTINUE OVER EASTERN SECTIONS INTO THIS AFTN THEN WINDS
DIMINISH BY TONIGHT AS HIGH PRESSURE RIDGE MOVES ACROSS. WINDS
INCREASE OUT OF THE S/SE TO 25 KTS MON NIGHT THROUGH TUE NIGHT
AHEAD OF A LOW PRESSURE SYSTEM MOVING NORTH OF LAKE SUPERIOR ON
WED. WARM FRONT SLIDING ACROSS LK SUPERIOR TUESDAY NIGHT AHEAD OF
THE LOW MAY RESULT IN A FEW STRONGER THUNDERSTORMS. LIGHTNING AND
HEAVY DOWNPOURS WOULD BE THE PRIMARY HAZARDS. EXPECT WINDS TO SHIFT
WESTERLY ON WEDNESDAY BEHIND THE COLD FRONT. POSSIBLE THAT GUSTS
COULD REACH 30 KTS. LIGHTER WINDS AGAIN LATE IN THE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR LSZ249>251-266-267.
GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR LSZ243>245-264-
265.
GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LSZ248.
LAKE MICHIGAN...
GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LMZ250.
&&
$$
SHORT TERM...VOSS
LONG TERM...JLA
AVIATION...VOSS
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
554 AM EDT SUN MAY 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 549 AM EDT SUN MAY 12 2013
WV IMAGERY AND RUC ANALYSIS SHOW STRONG SHORTWAVE/CLOSED LOW SYSTEM
NE OF LAKE SUPERIOR EARLY THIS MORNING. ENHANCEMENT ON THE BACK EDGE
OF THIS SYSTEM COMBINED WITH COLD ADVECTION IN ITS WAKE...HELPED
PRODUCE SOME MODERATE SNOW ACCUMULATION FROM NEGAUNEE/ISHPEMING EAST
THROUGH ALGER AND NRN SCHOOLCRAFT COUNTIES EARLIER THIS MORNING.
HOWEVER...IN THE PAST HR OR TWO RADAR RETURNS HAVE DIMINISHED
DRAMATICALLY IN AREAL EXTENT AND INTENSITY. HERE AT NWS MQT...SNOW
HAS DIMINISHED TO FLURRIES AND EXPECT THIS IS THE CASE AT MANY
LOCATIONS BASED ON RADAR RETURNS. LATEST VAD WIND PROFILE FROM MQT
RADAR ALSO SHOWS INDICATION OF SHARP LOWERING OF SUBSIDENCE
INVERSION FROM 9-10 KFT TO 6 KFT IN PAST HR WHICH IS ALSO CONSISTENT
WITH DIMINISHED RADAR RETURNS.
TODAY...GIVEN RECENT DIMINISHING RADAR TRENDS AND FACT THAT MODELS
SHOW BEST Q-VECT CONV FOR LAKE ENHANCEMENT TO BE MOVING EAST WITH
TIME THIS MORNING...HAVE DECIDED TO CANCEL THE WINTER WEATHER
ADVISORIES FOR NORTH CENTRAL COUNTIES. MOST PLACES FROM MQT COUNTY
EASTWARD WILL BE HARD PRESSED TO SEE MORE THAN HALF AN INCH OF
ADDITIONAL SNOW ACCUMULATION WITH ONLY A FEW LINGERING FLURRIES
NOTED TO THE WEST. UPDATED POPS TO REFLECT SHARP DIMINISHING TREND
TO PCPN THIS MORNING. LINGERING CYCLONIC FLOW AND -10C 8H TEMPS
MOVING ACROSS LAKE SUPERIOR COULD STILL SUPPORT PLENTY OF LAKE
STRATOCU CLOUDS THROUGH THE MORNING HRS...ESPECIALLY FOR
EASTERN COUNTIES DOWNWIND OF LONGER NNW FETCH ACROSS ERN LAKE
SUPERIOR. SHARP SUBSIDENCE/DRYING WITH A TRANSITION TO MORE NEUTRAL
OR ANTICYCLONIC FLOW FROM THE WEST BY AFTERNOON SHOULD ALLOW FOR
CLEARING SKIES FROM THE WEST THIS AFTERNOON. FAIRLY TIGHT NW PRES
GRAD ON THE BACKSIDE OF EXITING LOW WILL KEEP WINDS GUSTING TO NEAR
35 MPH OVER THE ERN HALF COUNTIES ESPECIALLY NEAR LAKE SUPERIOR.
OTHERWISE...UNSEASONABLY COLD CONDITIONS WILL CONTINUE WITH HIGHS
RANGING FROM AROUND 40 NORTH AND EAST TO MID 40S SOUTH CENTRAL.
TONIGHT...GIVEN RELATIVELY COLD HIGH TEMPS EXPECTED TODAY...SFC
RIDGING AND ASSOCIATED CLEARING BUILDING IN FROM THE W SHOULD ALLOW
SFC TEMPS TO PLUMMET TONIGHT TO RECORD OR NEAR RECORD LOW READINGS
ESPECIALLY OVER THE WRN CWA. LEANED ON THE LOWER END OF MODEL
GUIDANCE FOR MIN TEMPS WITH EXPECTED READINGS IN THE MID TO UPPER
TEENS OVER THE TYPICALLY COLD WRN INTERIOR LOCATIONS AND LOWER TO
MID 20S ACROSS THE REST OF THE INTERIOR CWA. TEMPS WILL STAY A BIT
WARMER NEAR THE GREAT LAKES...GENERALLY IN THE UPPER 20S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 549 AM EDT SUN MAY 12 2013
UPPER PATTERN FEATURING WESTERN CONUS RIDGING AND EASTERN CONUS
TROUGHING BECOMES MORE ZONAL THROUGH THE WEEK...RESULTING IN
WARMING TREND FOR UPPER GREAT LAKES. AS THE UPPER PATTERN BECOMES
MORE ZONAL EXPECT SFC LOW AND FRONTAL BOUNDARIES TO MOVE FROM
CENTRAL CANADA ACROSS THE GREAT LAKES TUESDAY THROUGH THURSDAY. BEST
CHANCE OF RAIN IN THIS PATTERN SHOULD BE LATER TUESDAY THROUGH
TUESDAY NIGHT AS WARM FRONT SLIDES ACROSS UPPER GREAT LAKES. EXTENT
OF COOLING BEHIND COLD FRONT WEDNESDAY INTO THURSDAY UNCERTAIN. EVEN
THE MODELS THAT ARE SHOWING THE MOST EMPHATIC COOLING /GFS AND NAM/
SHOW NOTHING TO THE EXTENT OF CURRENT COOLDOWN THAT IS CURRENTLY
OCCURRING. SO...BEYOND THIS TASTE OF WINTER AFFECTING THE REGION
THIS MORNING...EXPECT EXTENDED TO HOLD ONLY LIQUID PRECIPITATION.
HIGH PRESSURE BEGINS THE EXTENDED PERIOD OVER WESTERN GREAT LAKES.
RIDGE AXIS HEADS ACROSS REST OF GREAT LAKES BY MONDAY NIGHT ALLOWING
WARM AIR ADVECTION/RETURN FLOW TO DEVELOP. THROUGH DAY 2 LEANED ON
THE NAM/GFS SOUNDINGS TO TRY TO GAGE PRECIP CHANCES. MOISTURE
ADVECTION FOCUSED MAINLY ALOFT H85-H7 MONDAY NIGHT. SOME LGT SHOWERS
SEEM LIKELY IN MAX ADVECTION AREA MOVING WEST TO EAST ACROSS CWA.
ONCE MID-LEVEL MOISTURE/LIFT IS STRIPPED AWAY...SHALLOW MOISTURE
MAINLY BLO H9 IS ALL THAT IS LEFT ON TUESDAY. HINTS FROM MODELS THAT
MOISTURE MAY MIX OUT BY AFTN. LOWERED POPS BASED ON LIMITED MOISTURE
INTO TUESDAY AFTN. NEXT SURGE OF MOISTURE/TEMPERATURE ADVECTION AND
ELEVATED INSTABILITY COULD BRING SHOWERS/TSRA OVER GENERALLY WESTERN
CWA LATE TUESDAY AFTN. SE WINDS AHEAD OF WARM FRONT WITH MORE
INFLUENCE OFF LK MICHIGAN FOR MUCH OF CWA SHOULD KEEP TEMPS FROM
GETTING TOO WARM EVEN WITH ONLY SCT CLOUDS BY AFTN. WARMEST READINGS
INTO THE 70S INLAND WEST AND SOUTHWEST CWA WITH LESS LAKE MODIFIED
COOLER AIR. UPR 50S TO UPR 60S ELSEWHERE.
WARM FRONT PASSAGE/MAXIMUM LOW-LEVEL MOISTURE AND TEMP ADVECTION
STILL ON TRACK FOR TUESDAY NIGHT. HAS LOOKED THIS WAY FOR A WHILE
NOW. STILL THINKING THIS IS THE BEST CHANCE FOR SHOWERS AND TSRA
ACROSS CWA...BUT STILL MAY NOT BE WIDESPREAD EVENT FOR ALL CWA. SOME
DIFFERENCE HOW FAR SOUTH SHORTWAVE TROUGH/MID-LEVEL HEIGHT FALLS DIP
INTO UPR LAKES AND THIS IMPACTS SOUTHERN EXTENT OF PRIMARY UPPER
LEVEL JET AND ASSOCIATED DIVERGENCE TO ENHANCE PRECIP. PLACED LIKELY
POPS OVER NORTH AND EAST AND KEPT POPS SCATTERED FARTHER SOUTH. GIVEN
H85 DWPNTS OVER +12C AND 1-6KM MUCAPES OVER 1000J/KG AND SINCE AXIS
OF 925-850MB WIND MAX IS OVERHEAD...SHRA AND TSRA CANNOT BE COUNTED
OUT ANYWHERE THOUGH. STRONGST WINDS ALOFT ARE MORE OVER LAKE SUPERIOR
AND NORTH INTO ONTARIO SO THINK THIS IS WHERE BETTER CHANCE OF
STRONGER STORMS WOULD BE LOCATED. SEEMS THAT LIGHTNING AND HEAVY
DOWNPOURS WILL BE THE PRIMARY HAZARDS. THOUGH WBZERO HEIGHTS
11-12KFT IS ON THE HIGHER SIDE TO SEE LARGE HAIL...IT IS POSSIBLE
GIVEN STRONGER SHEAR AND H7-H5 LAPSE RATES OVER 7C/KM.
GOOD AGREEMENT THAT AREA OF ENHANCED PRECIP SWIFTLY CROSSES THE AREA
LATER TUESDAY NIGHT WITH COLD FRONTAL PASSAGE NOT TOO FAR BEHIND ON
WEDNESDAY MORNING. SUBSTANTIAL CLEARING IN THE OFFING ON WEDNESDAY
IN WAKE OF THE FRONT. 00Z ECMWF TRENDED SLIGHTLY TOWARD COLDER GFS
IDEA FOR H85 TEMPS IN WAKE OF COLD FRONT...BUT EVEN SO...EXPECT
SUNSHINE AND DEEP MIXING TO OFFSET THIS AND LEAD TO MAX TEMPS INTO
THE 70S SOUTHWEST AND SOUTH CENTRAL. READINGS IN THE 60S CLOSER TO
LK SUPERIOR. WINDS MAY END UP STRONGER THAN WHAT CONSENSUS SHOWED
BUT LEFT THEM ALONE FOR NOW. DID GO WITH LOWER BIAS CORRECTED MOS
DWPNTS IN THE AFTN GIVEN THE DEEP MIXING.
THURSDAY AND FRIDAY....A BIT UNSETTLED POTENTIALLY. PRIMARY SFC
FRONTAL BOUNDARY WILL REMAIN SOUTH OF UPR MICHIGAN. YET SINCE THE
AREA IS ON SOUTHERN EDGE OF TROUGH OVR CANADA...THE JET STREAM IS
TOO CLOSE BY TO NOT HAVE AT LEAST SLIGHT CHANCE POPS. MODELS HAVE
SHOWN SOME QPF FROM TIME TO TIME...ESPECIALLY LATER FRIDAY AND
FRIDAY NIGHT AS SECONDARY SFC TROUGH DIPS SOUTH ACROSS THE UPPER
GREAT LAKES.
BY NEXT WEEKEND THE MAIN ISSUE WILL BE INFLUENCE OF DEVELOPING LOW
PRESSURE OVER PLAINS. 12Z ECMWF FARTHER TO THE EAST...WHILE GFS AND
WPC HAND DRAWN PROGS KEEP LOW SHUNTED MORE OVER THE PLAINS AND SFC
RIDGE OVER THE UPR LAKES. CONSENSUS OF MODELS WHICH HAS DOUBLE
WEIGHTING OF THE TYPICALLY BETTER PERFORMING ECMWF SHOWS INCREASING
CHANCES OF SHOWERS BY LATER IN THE WEEKEND. TEMPS TO END THE
EXTENDED WILL BE AROUND NORMAL...THOUGH MAY REMAIN SLIGHTLY BELOW
NORMAL ALONG LK SUPERIOR DUE TO PREVAILING NORTHERLY SFC WINDS.
EVEN IF IT DOES END UP BELOW NORMAL...NO SNOW IS IN THE
FORECAST...WHICH IS CERTAINLY WELCOME NEWS FOR THOSE WEARY OF THE
WINTER THAT HAS BEEN RELUCTANT TO END.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 549 AM EDT SUN MAY 12 2013
SOME LAKE ENHANCEMENT SNOW SHOWERS WILL CONTINUE AT CMX AND SAW
OVERNIGHT WITH MVFR CONDITIONS AT CMX AND IFR CONDITIONS AT SAW IN
THE HEAVIER SNOW SHOWERS. DRY AIR COMES IN LATE SUN MORNING AND IWD
AND CMX WILL GO BACK TO VFR CONDITIONS. IT WILL TAKE A BIT LONGER TO
GET THE DRY AIR INTO SAW AND THE MVFR CIGS WILL SCATTER OUT BY SUN
AFTERNOON. WILL BE GUSTY THROUGH SUN AFTERNOON AT CMX AND SAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 549 AM EDT SUN MAY 12 2013
GALES CONTINUE OVER EASTERN SECTIONS INTO THIS AFTN THEN WINDS
DIMINISH BY TONIGHT AS HIGH PRESSURE RIDGE MOVES ACROSS. WINDS
INCREASE OUT OF THE S/SE TO 25 KTS MON NIGHT THROUGH TUE NIGHT
AHEAD OF A LOW PRESSURE SYSTEM MOVING NORTH OF LAKE SUPERIOR ON
WED. WARM FRONT SLIDING ACROSS LK SUPERIOR TUESDAY NIGHT AHEAD OF
THE LOW MAY RESULT IN A FEW STRONGER THUNDERSTORMS. LIGHTNING AND
HEAVY DOWNPOURS WOULD BE THE PRIMARY HAZARDS. EXPECT WINDS TO SHIFT
WESTERLY ON WEDNESDAY BEHIND THE COLD FRONT. POSSIBLE THAT GUSTS
COULD REACH 30 KTS. LIGHTER WINDS AGAIN LATE IN THE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR LSZ249>251-266-267.
GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR LSZ243>245-264-
265.
GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LSZ248.
LAKE MICHIGAN...
GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LMZ250.
&&
$$
SHORT TERM...VOSS
LONG TERM...JLA
AVIATION...07
MARINE...JLA
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1219 PM CDT SUN MAY 12 2013
.UPDATE...
ISSUED AT 820 AM CDT SUN MAY 12 2013
LIGHT SHOWERS CONTINUE TO SLIDE THROUGH PORTIONS OF THE REGION
THIS MORNING. A FEW LIGHTNING STRIKES HAVE BEEN REPORTED WITH
THESE SHOWERS. THEREFORE WENT AHEAD AND ADDED ISOLATED THUNDER TO
THE FORECAST THIS MORNING.
UPDATE ISSUED AT 543 AM CDT SUN MAY 12 2013
HAVE BEEN WATCHING TEMPERATURES WARM PRIOR TO DAWN AS THE CLOUDS
HAVE MOVED IN. THIS WAS PRETTY MUCH EXPECTED THAT WE WOULD WARM
ONCE THE CLOUDS MOVED IN THIS MORNING. THUS WE HAVE EXPIRED THE
FROST ADVISORY ACROSS NORTHWEST ZONES WHERE TEMPERATURES HAVE NOW
RISEN FROM THE LOWER AND MID 30S INTO THE MID AND UPPER 30S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 305 AM CDT SUN MAY 12 2013
THE PRIMARY FORECAST CONCERNS CENTER AROUND AREAS OF FROST ACROSS
NORTHEAST ZONES THIS MORNING...AS WELL AS ISOLATED MORNING
SPRINKLES FROM THE TRI CITES WEST AND SOUTH.
AS OF 3 AM...AN AREA OF SFC HIGH PRESSURE WAS SITUATED OVER
EASTERN NEBRASKA RESULTING IN CALM WINDS ALONG AND EAST OF HIGHWAY
281...WHICH IS RESULTING IN GOOD RADIATIONAL COOLING SINCE THIS AREA
HAS ALSO BEEN LARGELY CLOUD FREE THUS FAR. THE 3 AM TEMPERATURE AT
YORK WAS DOWN TO 34F AND IT IS LIKELY THAT LOW LYING AREAS ALONG
HIGHWAY 81...ESPECIALLY NORTH OF HIGHWAY 6 ARE ALREADY STARTING TO
SEE SOME FROST. HOWEVER...CLOUDS ARE ON THE INCREASE WEST OF
HIGHWAY 81 AND SHOULD QUICKLY MOVE OVER THE REST OF OUR FORECAST
AREA PRIOR TO DAWN. THIS WILL LIKELY RESULT IN RISING TEMPERATURES
ONCE THE CLOUDS MOVE IN NEAR DAWN. THEREFORE...FROST WILL BE
CONFINED TO LOW LYING AREAS OF OUR FAR NORTHEAST AND SHOULD NOT
LAST LONG. WILL LIKELY BE ABLE TO END THE FROST ADVISORY A BIT
EARLY.
PRECIPITATION CHANCES THIS MORNING ARE LOW AND THE RADAR HAS BEEN
RATHER QUIET THROUGH THE OVERNIGHT HOURS...WITH JUST A MINOR
RETURN OR TWO. MOST FORECAST MODELS CONTINUE TO INDICATE NO
QPF...BUT THE HRRR DOES SHOW A FEW ISOLATED SHOWERS.
THEREFORE...LOWERED POPS AND WILL JUST CALL FOR A SLIGHT CHANCE OF
ISOLATED SPRINKLES EARLY THIS MORNING. THERE COULD BE A FEW
SHOWERS AROUND...BUT JUST DO NOT THINK MOST OF THEM WILL MEASURE
MORE THAN A TRACE.
THE CLOUDS WILL BE MORE OF A MORNING FEATURE WITH CLEARING SKIES
BY AFTERNOON AND WARMER TEMPERATURES THANKS TO RETURN
SOUTHEASTERLY FLOW ON THE BACK SIDE OF THE SFC HIGH AS WELL AS
UPPER LEVEL RIDGING. AFTERNOON HIGHS WILL RANGE FROM THE UPPER 60S
EAST TO THE MID 70S WEST.
TONIGHT...THE UPPER RIDGE WILL CONTINUE TO BUILD INTO THE HIGH
PLAINS...SFC WINDS WILL REMAIN SOUTHERLY AND LOW TEMPERATURES WILL
BE MORE MILD. LOW TEMPERATURES WILL PRIMARILY BE IN THE MID TO
UPPER 40S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 305 AM CDT SUN MAY 12 2013
MAIN STORY: WE ARE ENTERING A DECIDELY MORE SUMMERLIKE PATTERN THAT
OFFERS POTENT HEAT AND MULTIPLE TSTM CHANCES. TEMPS WILL AVERAGE
ABOVE NORMAL THRU NEXT SAT WITH MUCH ABOVE NORMAL MON-TUE AS THE
ENTIRE FCST AREA WILL REACH 90F FOR THE FIRST TIME THIS SEASON.
AREAS W OF HWY 281 PROBABLY REACH OR EXCEED 90 BOTH DAYS. THEN THE
FOCUS SHIFTS TO TSTM CHANCES WITH A WRN TROF NEXT WEEKEND THAT COULD
THREATEN SEVERE WX.
PATTERN: THE PNA IS CURRENTLY PEAKING POSITIVE WITH A HIGH-AMPLITUDE
WRN N AMERICA RIDGE AND ERN TROF...WITH A CUT-OFF LOW OVER NRN MEX.
THE +PNA WILL HEAD BACK TO NEUTRAL BY THE MIDDLE OF NEXT WEEK...
INDICATING DEAMPLIFICATION OF THE LONG-WAVE /LGWV/ FLOW. TEMPS WILL
BE WARMER THAN NORMAL THRU NEXT SUN THEN SHOULD RETURN TO NEAR TO
POSSIBLY A LITTLE COOLER THAN NORMAL BY MON 5/20.
ALOFT: THE HIGH-AMPLITUDE WRN USA RIDGE WILL GET MOWED DOWN BY A
POTENT NEGATIVE TILT PV ANOMALY THAT MOVES ONSHORE IN THE PAC NW
LATE MON. THIS PV ANOMALY WILL TRACK E ACROSS SRN CANADA TUE
INITIATING ZONAL FLOW FOR WED-THU. IN THE MEANTIME...THE NRN MEX
CUT-OFF LOW WILL BECOME MOBILE AND HEAD ACROSS THE SRN PLAINS...TOO
LATE TO INFUSE ANY MSTR THIS FAR N. A BROAD TROF THEN DEVELOPS OVER
THE WRN USA FRI AND LASTS INTO EARLY THE FOLLOWING WEEK. MULTIPLE
LOW AMPLITUDE PV ANOMALIES WILL SHOULD INSTIGATE PERIODIC TSTM
THREATS.
SFC: THE WARM FRONT DEPARTS TO THE E MON AS LOW PRES MIGRATES ACROSS
SRN CANADA. ITS ASSOCIATED COOL FRONT WILL MOVE THRU TUE NGT AND
BECOME STATIONARY NEAR THE NEB-KS BORDER WED-THU. IT MAY HEAD BACK N
TO NEAR THE NEB-SD BORDER FRI-SAT. THE DRYLINE WILL INTERSECT THIS
FRONT JUST W OF THE FCST AREA.
MODELS: 00Z GEM / 12Z AND 00Z EC / 18Z AND 00Z GFS / 12Z AND 00Z
UKMET ARE IN GOOD AGREEMENT ON THE OVERALL THEME THRU 00Z/SAT...
DEAMPLIFICATION TO ZONAL FLOW THEN A MODEST AMPLITUDE TROF MOVING
INTO THE WRN USA NEXT WEEKEND. TYPICAL TIMING DIFFERENCES BEGIN TO
SHOW UP NEXT SAT WITH THE 00Z GFS FASTER THAN ALL THE OTHER GUIDANCE
/AND EVEN ITS 18Z RUN/ ADVANCING THE TROF INTO THE ROCKIES.
HAZARDS: NOTHING DEFINABLE AT THIS POINT BUT MULTIPLE CHANCES FOR
TSTMS EXIST TUE NGT-SAT. IT/S TOO EARLY TO PIN DOWN LOCATION/TIMING/
COVERAGE AND INTENSITY...BUT ODDS ARE INCREASING THAT WE COULD HAVE
TO DEAL WITH AT LEAST ONE EPISODE OF SEVERE.
THE DAILY DETAILS...
MON: THE WARM FRONT WILL BISECT THE FCST AREA AT DAYBREAK. ANY
FRONTAL CLOUDS WILL CLEAR THE AREA AS THE FRONT DEPARTS TO THE E.
THIS WILL RESULT IN A SUNNY VERY WARM DAY...BUT W OF HWY 281 IT WILL
BE HOT /90-95F/. +24C AT H8 AND 582 HGTS AT H5.
TUE: SUNNY AND HOT. 93-98F. +26C AT H8 AND 582 HGTS AT H5. H8 TEMPS
2 STANDARD DEVIATIONS ABOVE NORMAL. HIGHS WILL BE 25F ABOVE NORMAL.
GRI AND HSI WILL BE WITHIN ABOUT 4F OF RECORD HIGHS BUT THEY SHOULD
BE SAFELY OUT OF REACH. GRI 99-1941. HSI 97-1941.
TUE NGT: COOL FRONTAL PASSAGE. IT/S PROBABLY DRY MOST LOCATIONS. AN
ISOLATE TSTM IS POSSIBLE.
WHILE THIS COOL FRONT WILL END THE HEAT...TEMPS WILL STILL REMAIN
8-15F ABOVE NORMAL WED-SAT.
WED: POSSIBLY A LEFT OVER SHWR OR TSTM ALONG THE FRONT?
THU-SAT: OVERALL SHOULD AVERAGE P/CLOUDY AND DRY MOST OF THE TIME.
HOWEVER...MULTIPLE EPISODES OF TSTMS APPEAR POSSIBLE ALONG THE
FRONT/DRYLINE.
OF PARTICULAR INTEREST IS THE RISING HGTS OVER THE ERN USA. THIS
WILL PREVENT TUE NGT/S COOL FRONT FROM PENETRATING FAR TO THE S.
HIGH PRES WILL PARK ITSELF OFF THE CAROLINA/S...SETTING UP SEVERAL
DAYS OF UNINTERRUPTED RICH GULF MSTR FLUX N INTO THE PLAINS. BY WED
AFTN H8 DWPTS OF 8+C WILL BE IN PLACE WITH SFC DWPTS INTO THE 50S
THU AND AROUND 60 FRI-SAT. DIURNAL OSCILLATIONS IN THE LLJ WILL
PROBABLY TRIGGER MCS ACTIVITY OVER THE NRN/CNTRL PLAINS. INSTABILITY
WILL BUILD A LITTLE MORE EACH DAY.
SEVERE: AM GROWING INCREASINGLY CONCERNED ABOUT THE POTENTIAL FOR A
COUPLE EPISODES OF SVR TSTMS IN THE THU-MON TIME FRAME. THU-SAT
WOULD PROBABLY TAKE THE FORM OF A FORWARD PROPAGATING MCS. SUN COULD
BE SUBSTANTIALLY MORE INTERESTING AS THE LFQ OF A 120 KT ULJ EJECTS
INTO THE CNTRL PLAINS.
IF WE DO GET AN MCS THRU HERE IT COULD SERIOUSLY IMPACT OUR TEMPS
THE FOLLOWING DAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1220 PM CDT SUN MAY 12 2013
VFR CONDITIONS WILL CONTINUE THROUGHOUT THE TAF PERIOD. AS A
SURFACE LOW PRESSURE SYSTEM SKIRTS TO OUR SOUTHWEST...SUSTAINED SOUTHEAST
WINDS WILL CONTINUE AROUND 12 KTS THROUGHOUT THE AFTERNOON. WINDS
WILL THEN DECREASE TO NEAR 10 KTS FOR THE EVENING HOURS. AN UPPER
LEVEL RIDGE WILL CONTINUE TO SHIFT EASTWARD TOWARDS THE PLAINS
TODAY WHICH WILL RESULT IN AT LEAST SOME PARTIAL HIGH LEVEL CIRRUS
CLOUDS ACROSS THE AREA OVERNIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...SALTZMAN
SHORT TERM...WESELY
LONG TERM...HALBLAUB
AVIATION...SALTZMAN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
820 AM CDT SUN MAY 12 2013
.UPDATE...
ISSUED AT 820 AM CDT SUN MAY 12 2013
LIGHT SHOWERS CONTINUE TO SLIDE THROUGH PORTIONS OF THE REGION
THIS MORNING. A FEW LIGHTNING STRIKES HAVE BEEN REPORTED WITH
THESE SHOWERS. THEREFORE WENT AHEAD AND ADDED ISOLATED THUNDER TO
THE FORECAST THIS MORNING.
UPDATE ISSUED AT 543 AM CDT SUN MAY 12 2013
HAVE BEEN WATCHING TEMPERATURES WARM PRIOR TO DAWN AS THE CLOUDS
HAVE MOVED IN. THIS WAS PRETTY MUCH EXPECTED THAT WE WOULD WARM
ONCE THE CLOUDS MOVED IN THIS MORNING. THUS WE HAVE EXPIRED THE
FROST ADVISORY ACROSS NORTHWEST ZONES WHERE TEMPERATURES HAVE NOW
RISEN FROM THE LOWER AND MID 30S INTO THE MID AND UPPER 30S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 305 AM CDT SUN MAY 12 2013
THE PRIMARY FORECAST CONCERNS CENTER AROUND AREAS OF FROST ACROSS
NORTHEAST ZONES THIS MORNING...AS WELL AS ISOLATED MORNING
SPRINKLES FROM THE TRI CITES WEST AND SOUTH.
AS OF 3 AM...AN AREA OF SFC HIGH PRESSURE WAS SITUATED OVER
EASTERN NEBRASKA RESULTING IN CALM WINDS ALONG AND EAST OF HIGHWAY
281...WHICH IS RESULTING IN GOOD RADIATIONAL COOLING SINCE THIS AREA
HAS ALSO BEEN LARGELY CLOUD FREE THUS FAR. THE 3 AM TEMPERATURE AT
YORK WAS DOWN TO 34F AND IT IS LIKELY THAT LOW LYING AREAS ALONG
HIGHWAY 81...ESPECIALLY NORTH OF HIGHWAY 6 ARE ALREADY STARTING TO
SEE SOME FROST. HOWEVER...CLOUDS ARE ON THE INCREASE WEST OF
HIGHWAY 81 AND SHOULD QUICKLY MOVE OVER THE REST OF OUR FORECAST
AREA PRIOR TO DAWN. THIS WILL LIKELY RESULT IN RISING TEMPERATURES
ONCE THE CLOUDS MOVE IN NEAR DAWN. THEREFORE...FROST WILL BE
CONFINED TO LOW LYING AREAS OF OUR FAR NORTHEAST AND SHOULD NOT
LAST LONG. WILL LIKELY BE ABLE TO END THE FROST ADVISORY A BIT
EARLY.
PRECIPITATION CHANCES THIS MORNING ARE LOW AND THE RADAR HAS BEEN
RATHER QUIET THROUGH THE OVERNIGHT HOURS...WITH JUST A MINOR
RETURN OR TWO. MOST FORECAST MODELS CONTINUE TO INDICATE NO
QPF...BUT THE HRRR DOES SHOW A FEW ISOLATED SHOWERS.
THEREFORE...LOWERED POPS AND WILL JUST CALL FOR A SLIGHT CHANCE OF
ISOLATED SPRINKLES EARLY THIS MORNING. THERE COULD BE A FEW
SHOWERS AROUND...BUT JUST DO NOT THINK MOST OF THEM WILL MEASURE
MORE THAN A TRACE.
THE CLOUDS WILL BE MORE OF A MORNING FEATURE WITH CLEARING SKIES
BY AFTERNOON AND WARMER TEMPERATURES THANKS TO RETURN
SOUTHEASTERLY FLOW ON THE BACK SIDE OF THE SFC HIGH AS WELL AS
UPPER LEVEL RIDGING. AFTERNOON HIGHS WILL RANGE FROM THE UPPER 60S
EAST TO THE MID 70S WEST.
TONIGHT...THE UPPER RIDGE WILL CONTINUE TO BUILD INTO THE HIGH
PLAINS...SFC WINDS WILL REMAIN SOUTHERLY AND LOW TEMPERATURES WILL
BE MORE MILD. LOW TEMPERATURES WILL PRIMARILY BE IN THE MID TO
UPPER 40S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 305 AM CDT SUN MAY 12 2013
MAIN STORY: WE ARE ENTERING A DECIDELY MORE SUMMERLIKE PATTERN THAT
OFFERS POTENT HEAT AND MULTIPLE TSTM CHANCES. TEMPS WILL AVERAGE
ABOVE NORMAL THRU NEXT SAT WITH MUCH ABOVE NORMAL MON-TUE AS THE
ENTIRE FCST AREA WILL REACH 90F FOR THE FIRST TIME THIS SEASON.
AREAS W OF HWY 281 PROBABLY REACH OR EXCEED 90 BOTH DAYS. THEN THE
FOCUS SHIFTS TO TSTM CHANCES WITH A WRN TROF NEXT WEEKEND THAT COULD
THREATEN SEVERE WX.
PATTERN: THE PNA IS CURRENTLY PEAKING POSITIVE WITH A HIGH-AMPLITUDE
WRN N AMERICA RIDGE AND ERN TROF...WITH A CUT-OFF LOW OVER NRN MEX.
THE +PNA WILL HEAD BACK TO NEUTRAL BY THE MIDDLE OF NEXT WEEK...
INDICATING DEAMPLIFICATION OF THE LONG-WAVE /LGWV/ FLOW. TEMPS WILL
BE WARMER THAN NORMAL THRU NEXT SUN THEN SHOULD RETURN TO NEAR TO
POSSIBLY A LITTLE COOLER THAN NORMAL BY MON 5/20.
ALOFT: THE HIGH-AMPLITUDE WRN USA RIDGE WILL GET MOWED DOWN BY A
POTENT NEGATIVE TILT PV ANOMALY THAT MOVES ONSHORE IN THE PAC NW
LATE MON. THIS PV ANOMALY WILL TRACK E ACROSS SRN CANADA TUE
INITIATING ZONAL FLOW FOR WED-THU. IN THE MEANTIME...THE NRN MEX
CUT-OFF LOW WILL BECOME MOBILE AND HEAD ACROSS THE SRN PLAINS...TOO
LATE TO INFUSE ANY MSTR THIS FAR N. A BROAD TROF THEN DEVELOPS OVER
THE WRN USA FRI AND LASTS INTO EARLY THE FOLLOWING WEEK. MULTIPLE
LOW AMPLITUDE PV ANOMALIES WILL SHOULD INSTIGATE PERIODIC TSTM
THREATS.
SFC: THE WARM FRONT DEPARTS TO THE E MON AS LOW PRES MIGRATES ACROSS
SRN CANADA. ITS ASSOCIATED COOL FRONT WILL MOVE THRU TUE NGT AND
BECOME STATIONARY NEAR THE NEB-KS BORDER WED-THU. IT MAY HEAD BACK N
TO NEAR THE NEB-SD BORDER FRI-SAT. THE DRYLINE WILL INTERSECT THIS
FRONT JUST W OF THE FCST AREA.
MODELS: 00Z GEM / 12Z AND 00Z EC / 18Z AND 00Z GFS / 12Z AND 00Z
UKMET ARE IN GOOD AGREEMENT ON THE OVERALL THEME THRU 00Z/SAT...
DEAMPLIFICATION TO ZONAL FLOW THEN A MODEST AMPLITUDE TROF MOVING
INTO THE WRN USA NEXT WEEKEND. TYPICAL TIMING DIFFERENCES BEGIN TO
SHOW UP NEXT SAT WITH THE 00Z GFS FASTER THAN ALL THE OTHER GUIDANCE
/AND EVEN ITS 18Z RUN/ ADVANCING THE TROF INTO THE ROCKIES.
HAZARDS: NOTHING DEFINABLE AT THIS POINT BUT MULTIPLE CHANCES FOR
TSTMS EXIST TUE NGT-SAT. IT/S TOO EARLY TO PIN DOWN LOCATION/TIMING/
COVERAGE AND INTENSITY...BUT ODDS ARE INCREASING THAT WE COULD HAVE
TO DEAL WITH AT LEAST ONE EPISODE OF SEVERE.
THE DAILY DETAILS...
MON: THE WARM FRONT WILL BISECT THE FCST AREA AT DAYBREAK. ANY
FRONTAL CLOUDS WILL CLEAR THE AREA AS THE FRONT DEPARTS TO THE E.
THIS WILL RESULT IN A SUNNY VERY WARM DAY...BUT W OF HWY 281 IT WILL
BE HOT /90-95F/. +24C AT H8 AND 582 HGTS AT H5.
TUE: SUNNY AND HOT. 93-98F. +26C AT H8 AND 582 HGTS AT H5. H8 TEMPS
2 STANDARD DEVIATIONS ABOVE NORMAL. HIGHS WILL BE 25F ABOVE NORMAL.
GRI AND HSI WILL BE WITHIN ABOUT 4F OF RECORD HIGHS BUT THEY SHOULD
BE SAFELY OUT OF REACH. GRI 99-1941. HSI 97-1941.
TUE NGT: COOL FRONTAL PASSAGE. IT/S PROBABLY DRY MOST LOCATIONS. AN
ISOLATE TSTM IS POSSIBLE.
WHILE THIS COOL FRONT WILL END THE HEAT...TEMPS WILL STILL REMAIN
8-15F ABOVE NORMAL WED-SAT.
WED: POSSIBLY A LEFT OVER SHWR OR TSTM ALONG THE FRONT?
THU-SAT: OVERALL SHOULD AVERAGE P/CLOUDY AND DRY MOST OF THE TIME.
HOWEVER...MULTIPLE EPISODES OF TSTMS APPEAR POSSIBLE ALONG THE
FRONT/DRYLINE.
OF PARTICULAR INTEREST IS THE RISING HGTS OVER THE ERN USA. THIS
WILL PREVENT TUE NGT/S COOL FRONT FROM PENETRATING FAR TO THE S.
HIGH PRES WILL PARK ITSELF OFF THE CAROLINA/S...SETTING UP SEVERAL
DAYS OF UNINTERRUPTED RICH GULF MSTR FLUX N INTO THE PLAINS. BY WED
AFTN H8 DWPTS OF 8+C WILL BE IN PLACE WITH SFC DWPTS INTO THE 50S
THU AND AROUND 60 FRI-SAT. DIURNAL OSCILLATIONS IN THE LLJ WILL
PROBABLY TRIGGER MCS ACTIVITY OVER THE NRN/CNTRL PLAINS. INSTABILITY
WILL BUILD A LITTLE MORE EACH DAY.
SEVERE: AM GROWING INCREASINGLY CONCERNED ABOUT THE POTENTIAL FOR A
COUPLE EPISODES OF SVR TSTMS IN THE THU-MON TIME FRAME. THU-SAT
WOULD PROBABLY TAKE THE FORM OF A FORWARD PROPAGATING MCS. SUN COULD
BE SUBSTANTIALLY MORE INTERESTING AS THE LFQ OF A 120 KT ULJ EJECTS
INTO THE CNTRL PLAINS.
IF WE DO GET AN MCS THRU HERE IT COULD SERIOUSLY IMPACT OUR TEMPS
THE FOLLOWING DAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 543 AM CDT SUN MAY 12 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF VALID PERIOD. THE WIND
WILL REMAIN OUT OF THE SOUTHEAST. THERE ARE A FEW ISOLATED
SPRINKLES AROUND THE AREA THIS MORNING BUT THESE WILL BE HIT AND
MISS AND QUICKLY OUT OF THE AREA BY MID MORNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...SALTZMAN
SHORT TERM...WESELY
LONG TERM...HALBLAUB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
556 AM CDT SUN MAY 12 2013
.UPDATE...
ISSUED AT 543 AM CDT SUN MAY 12 2013
HAVE BEEN WATCHING TEMPERATURES WARM PRIOR TO DAWN AS THE CLOUDS
HAVE MOVED IN. THIS WAS PRETTY MUCH EXPECTED THAT WE WOULD WARM
ONCE THE CLOUDS MOVED IN THIS MORNING. THUS WE HAVE EXPIRED THE
FROST ADVISORY ACROSS NORTHWEST ZONES WHERE TEMPERATURES HAVE NOW
RISEN FROM THE LOWER AND MID 30S INTO THE MID AND UPPER 30S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 305 AM CDT SUN MAY 12 2013
THE PRIMARY FORECAST CONCERNS CENTER AROUND AREAS OF FROST ACROSS
NORTHEAST ZONES THIS MORNING...AS WELL AS ISOLATED MORNING
SPRINKLES FROM THE TRI CITES WEST AND SOUTH.
AS OF 3 AM...AN AREA OF SFC HIGH PRESSURE WAS SITUATED OVER
EASTERN NEBRASKA RESULTING IN CALM WINDS ALONG AND EAST OF HIGHWAY
281...WHICH IS RESULTING IN GOOD RADIATIONAL COOLING SINCE THIS AREA
HAS ALSO BEEN LARGELY CLOUD FREE THUS FAR. THE 3 AM TEMPERATURE AT
YORK WAS DOWN TO 34F AND IT IS LIKELY THAT LOW LYING AREAS ALONG
HIGHWAY 81...ESPECIALLY NORTH OF HIGHWAY 6 ARE ALREADY STARTING TO
SEE SOME FROST. HOWEVER...CLOUDS ARE ON THE INCREASE WEST OF
HIGHWAY 81 AND SHOULD QUICKLY MOVE OVER THE REST OF OUR FORECAST
AREA PRIOR TO DAWN. THIS WILL LIKELY RESULT IN RISING TEMPERATURES
ONCE THE CLOUDS MOVE IN NEAR DAWN. THEREFORE...FROST WILL BE
CONFINED TO LOW LYING AREAS OF OUR FAR NORTHEAST AND SHOULD NOT
LAST LONG. WILL LIKELY BE ABLE TO END THE FROST ADVISORY A BIT
EARLY.
PRECIPITATION CHANCES THIS MORNING ARE LOW AND THE RADAR HAS BEEN
RATHER QUIET THROUGH THE OVERNIGHT HOURS...WITH JUST A MINOR
RETURN OR TWO. MOST FORECAST MODELS CONTINUE TO INDICATE NO
QPF...BUT THE HRRR DOES SHOW A FEW ISOLATED SHOWERS.
THEREFORE...LOWERED POPS AND WILL JUST CALL FOR A SLIGHT CHANCE OF
ISOLATED SPRINKLES EARLY THIS MORNING. THERE COULD BE A FEW
SHOWERS AROUND...BUT JUST DO NOT THINK MOST OF THEM WILL MEASURE
MORE THAN A TRACE.
THE CLOUDS WILL BE MORE OF A MORNING FEATURE WITH CLEARING SKIES
BY AFTERNOON AND WARMER TEMPERATURES THANKS TO RETURN
SOUTHEASTERLY FLOW ON THE BACK SIDE OF THE SFC HIGH AS WELL AS
UPPER LEVEL RIDGING. AFTERNOON HIGHS WILL RANGE FROM THE UPPER 60S
EAST TO THE MID 70S WEST.
TONIGHT...THE UPPER RIDGE WILL CONTINUE TO BUILD INTO THE HIGH
PLAINS...SFC WINDS WILL REMAIN SOUTHERLY AND LOW TEMPERATURES WILL
BE MORE MILD. LOW TEMPERATURES WILL PRIMARILY BE IN THE MID TO
UPPER 40S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 305 AM CDT SUN MAY 12 2013
MAIN STORY: WE ARE ENTERING A DECIDELY MORE SUMMERLIKE PATTERN THAT
OFFERS POTENT HEAT AND MULTIPLE TSTM CHANCES. TEMPS WILL AVERAGE
ABOVE NORMAL THRU NEXT SAT WITH MUCH ABOVE NORMAL MON-TUE AS THE
ENTIRE FCST AREA WILL REACH 90F FOR THE FIRST TIME THIS SEASON.
AREAS W OF HWY 281 PROBABLY REACH OR EXCEED 90 BOTH DAYS. THEN THE
FOCUS SHIFTS TO TSTM CHANCES WITH A WRN TROF NEXT WEEKEND THAT COULD
THREATEN SEVERE WX.
PATTERN: THE PNA IS CURRENTLY PEAKING POSITIVE WITH A HIGH-AMPLITUDE
WRN N AMERICA RIDGE AND ERN TROF...WITH A CUT-OFF LOW OVER NRN MEX.
THE +PNA WILL HEAD BACK TO NEUTRAL BY THE MIDDLE OF NEXT WEEK...
INDICATING DEAMPLIFICATION OF THE LONG-WAVE /LGWV/ FLOW. TEMPS WILL
BE WARMER THAN NORMAL THRU NEXT SUN THEN SHOULD RETURN TO NEAR TO
POSSIBLY A LITTLE COOLER THAN NORMAL BY MON 5/20.
ALOFT: THE HIGH-AMPLITUDE WRN USA RIDGE WILL GET MOWED DOWN BY A
POTENT NEGATIVE TILT PV ANOMALY THAT MOVES ONSHORE IN THE PAC NW
LATE MON. THIS PV ANOMALY WILL TRACK E ACROSS SRN CANADA TUE
INITIATING ZONAL FLOW FOR WED-THU. IN THE MEANTIME...THE NRN MEX
CUT-OFF LOW WILL BECOME MOBILE AND HEAD ACROSS THE SRN PLAINS...TOO
LATE TO INFUSE ANY MSTR THIS FAR N. A BROAD TROF THEN DEVELOPS OVER
THE WRN USA FRI AND LASTS INTO EARLY THE FOLLOWING WEEK. MULTIPLE
LOW AMPLITUDE PV ANOMALIES WILL SHOULD INSTIGATE PERIODIC TSTM
THREATS.
SFC: THE WARM FRONT DEPARTS TO THE E MON AS LOW PRES MIGRATES ACROSS
SRN CANADA. ITS ASSOCIATED COOL FRONT WILL MOVE THRU TUE NGT AND
BECOME STATIONARY NEAR THE NEB-KS BORDER WED-THU. IT MAY HEAD BACK N
TO NEAR THE NEB-SD BORDER FRI-SAT. THE DRYLINE WILL INTERSECT THIS
FRONT JUST W OF THE FCST AREA.
MODELS: 00Z GEM / 12Z AND 00Z EC / 18Z AND 00Z GFS / 12Z AND 00Z
UKMET ARE IN GOOD AGREEMENT ON THE OVERALL THEME THRU 00Z/SAT...
DEAMPLIFICATION TO ZONAL FLOW THEN A MODEST AMPLITUDE TROF MOVING
INTO THE WRN USA NEXT WEEKEND. TYPICAL TIMING DIFFERENCES BEGIN TO
SHOW UP NEXT SAT WITH THE 00Z GFS FASTER THAN ALL THE OTHER GUIDANCE
/AND EVEN ITS 18Z RUN/ ADVANCING THE TROF INTO THE ROCKIES.
HAZARDS: NOTHING DEFINABLE AT THIS POINT BUT MULTIPLE CHANCES FOR
TSTMS EXIST TUE NGT-SAT. IT/S TOO EARLY TO PIN DOWN LOCATION/TIMING/
COVERAGE AND INTENSITY...BUT ODDS ARE INCREASING THAT WE COULD HAVE
TO DEAL WITH AT LEAST ONE EPISODE OF SEVERE.
THE DAILY DETAILS...
MON: THE WARM FRONT WILL BISECT THE FCST AREA AT DAYBREAK. ANY
FRONTAL CLOUDS WILL CLEAR THE AREA AS THE FRONT DEPARTS TO THE E.
THIS WILL RESULT IN A SUNNY VERY WARM DAY...BUT W OF HWY 281 IT WILL
BE HOT /90-95F/. +24C AT H8 AND 582 HGTS AT H5.
TUE: SUNNY AND HOT. 93-98F. +26C AT H8 AND 582 HGTS AT H5. H8 TEMPS
2 STANDARD DEVIATIONS ABOVE NORMAL. HIGHS WILL BE 25F ABOVE NORMAL.
GRI AND HSI WILL BE WITHIN ABOUT 4F OF RECORD HIGHS BUT THEY SHOULD
BE SAFELY OUT OF REACH. GRI 99-1941. HSI 97-1941.
TUE NGT: COOL FRONTAL PASSAGE. IT/S PROBABLY DRY MOST LOCATIONS. AN
ISOLATE TSTM IS POSSIBLE.
WHILE THIS COOL FRONT WILL END THE HEAT...TEMPS WILL STILL REMAIN
8-15F ABOVE NORMAL WED-SAT.
WED: POSSIBLY A LEFT OVER SHWR OR TSTM ALONG THE FRONT?
THU-SAT: OVERALL SHOULD AVERAGE P/CLOUDY AND DRY MOST OF THE TIME.
HOWEVER...MULTIPLE EPISODES OF TSTMS APPEAR POSSIBLE ALONG THE
FRONT/DRYLINE.
OF PARTICULAR INTEREST IS THE RISING HGTS OVER THE ERN USA. THIS
WILL PREVENT TUE NGT/S COOL FRONT FROM PENETRATING FAR TO THE S.
HIGH PRES WILL PARK ITSELF OFF THE CAROLINA/S...SETTING UP SEVERAL
DAYS OF UNINTERRUPTED RICH GULF MSTR FLUX N INTO THE PLAINS. BY WED
AFTN H8 DWPTS OF 8+C WILL BE IN PLACE WITH SFC DWPTS INTO THE 50S
THU AND AROUND 60 FRI-SAT. DIURNAL OSCILLATIONS IN THE LLJ WILL
PROBABLY TRIGGER MCS ACTIVITY OVER THE NRN/CNTRL PLAINS. INSTABILITY
WILL BUILD A LITTLE MORE EACH DAY.
SEVERE: AM GROWING INCREASINGLY CONCERNED ABOUT THE POTENTIAL FOR A
COUPLE EPISODES OF SVR TSTMS IN THE THU-MON TIME FRAME. THU-SAT
WOULD PROBABLY TAKE THE FORM OF A FORWARD PROPAGATING MCS. SUN COULD
BE SUBSTANTIALLY MORE INTERESTING AS THE LFQ OF A 120 KT ULJ EJECTS
INTO THE CNTRL PLAINS.
IF WE DO GET AN MCS THRU HERE IT COULD SERIOUSLY IMPACT OUR TEMPS
THE FOLLOWING DAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 543 AM CDT SUN MAY 12 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF VALID PERIOD. THE WIND
WILL REMAIN OUT OF THE SOUTHEAST. THERE ARE A FEW ISOLATED
SPRINKLES AROUND THE AREA THIS MORNING BUT THESE WILL BE HIT AND
MISS AND QUICKLY OUT OF THE AREA BY MID MORNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...WESELY
SHORT TERM...WESELY
LONG TERM...HALBLAUB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
352 AM CDT SUN MAY 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 305 AM CDT SUN MAY 12 2013
THE PRIMARY FORECAST CONCERNS CENTER AROUND AREAS OF FROST ACROSS
NORTHEAST ZONES THIS MORNING...AS WELL AS ISOLATED MORNING
SPRINKLES FROM THE TRI CITES WEST AND SOUTH.
AS OF 3 AM...AN AREA OF SFC HIGH PRESSURE WAS SITUATED OVER
EASTERN NEBRASKA RESULTING IN CALM WINDS ALONG AND EAST OF HIGHWAY
281...WHICH IS RESULTING IN GOOD RADIATIONAL COOLING SINCE THIS AREA
HAS ALSO BEEN LARGELY CLOUD FREE THUS FAR. THE 3 AM TEMPERATURE AT
YORK WAS DOWN TO 34F AND IT IS LIKELY THAT LOW LYING AREAS ALONG
HIGHWAY 81...ESPECIALLY NORTH OF HIGHWAY 6 ARE ALREADY STARTING TO
SEE SOME FROST. HOWEVER...CLOUDS ARE ON THE INCREASE WEST OF
HIGHWAY 81 AND SHOULD QUICKLY MOVE OVER THE REST OF OUR FORECAST
AREA PRIOR TO DAWN. THIS WILL LIKELY RESULT IN RISING TEMPERATURES
ONCE THE CLOUDS MOVE IN NEAR DAWN. THEREFORE...FROST WILL BE
CONFINED TO LOW LYING AREAS OF OUR FAR NORTHEAST AND SHOULD NOT
LAST LONG. WILL LIKELY BE ABLE TO END THE FROST ADVISORY A BIT
EARLY.
PRECIPITATION CHANCES THIS MORNING ARE LOW AND THE RADAR HAS BEEN
RATHER QUIET THROUGH THE OVERNIGHT HOURS...WITH JUST A MINOR
RETURN OR TWO. MOST FORECAST MODELS CONTINUE TO INDICATE NO
QPF...BUT THE HRRR DOES SHOW A FEW ISOLATED SHOWERS.
THEREFORE...LOWERED POPS AND WILL JUST CALL FOR A SLIGHT CHANCE OF
ISOLATED SPRINKLES EARLY THIS MORNING. THERE COULD BE A FEW
SHOWERS AROUND...BUT JUST DO NOT THINK MOST OF THEM WILL MEASURE
MORE THAN A TRACE.
THE CLOUDS WILL BE MORE OF A MORNING FEATURE WITH CLEARING SKIES
BY AFTERNOON AND WARMER TEMPERATURES THANKS TO RETURN
SOUTHEASTERLY FLOW ON THE BACK SIDE OF THE SFC HIGH AS WELL AS
UPPER LEVEL RIDGING. AFTERNOON HIGHS WILL RANGE FROM THE UPPER 60S
EAST TO THE MID 70S WEST.
TONIGHT...THE UPPER RIDGE WILL CONTINUE TO BUILD INTO THE HIGH
PLAINS...SFC WINDS WILL REMAIN SOUTHERLY AND LOW TEMPERATURES WILL
BE MORE MILD. LOW TEMPERATURES WILL PRIMARILY BE IN THE MID TO
UPPER 40S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 305 AM CDT SUN MAY 12 2013
MAIN STORY: WE ARE ENTERING A DECIDELY MORE SUMMERLIKE PATTERN THAT
OFFERS POTENT HEAT AND MULTIPLE TSTM CHANCES. TEMPS WILL AVERAGE
ABOVE NORMAL THRU NEXT SAT WITH MUCH ABOVE NORMAL MON-TUE AS THE
ENTIRE FCST AREA WILL REACH 90F FOR THE FIRST TIME THIS SEASON.
AREAS W OF HWY 281 PROBABLY REACH OR EXCEED 90 BOTH DAYS. THEN THE
FOCUS SHIFTS TO TSTM CHANCES WITH A WRN TROF NEXT WEEKEND THAT COULD
THREATEN SEVERE WX.
PATTERN: THE PNA IS CURRENTLY PEAKING POSITIVE WITH A HIGH-AMPLITUDE
WRN N AMERICA RIDGE AND ERN TROF...WITH A CUT-OFF LOW OVER NRN MEX.
THE +PNA WILL HEAD BACK TO NEUTRAL BY THE MIDDLE OF NEXT WEEK...
INDICATING DEAMPLIFICATION OF THE LONG-WAVE /LGWV/ FLOW. TEMPS WILL
BE WARMER THAN NORMAL THRU NEXT SUN THEN SHOULD RETURN TO NEAR TO
POSSIBLY A LITTLE COOLER THAN NORMAL BY MON 5/20.
ALOFT: THE HIGH-AMPLITUDE WRN USA RIDGE WILL GET MOWED DOWN BY A
POTENT NEGATIVE TILT PV ANOMALY THAT MOVES ONSHORE IN THE PAC NW
LATE MON. THIS PV ANOMALY WILL TRACK E ACROSS SRN CANADA TUE
INITIATING ZONAL FLOW FOR WED-THU. IN THE MEANTIME...THE NRN MEX
CUT-OFF LOW WILL BECOME MOBILE AND HEAD ACROSS THE SRN PLAINS...TOO
LATE TO INFUSE ANY MSTR THIS FAR N. A BROAD TROF THEN DEVELOPS OVER
THE WRN USA FRI AND LASTS INTO EARLY THE FOLLOWING WEEK. MULTIPLE
LOW AMPLITUDE PV ANOMALIES WILL SHOULD INSTIGATE PERIODIC TSTM
THREATS.
SFC: THE WARM FRONT DEPARTS TO THE E MON AS LOW PRES MIGRATES ACROSS
SRN CANADA. ITS ASSOCIATED COOL FRONT WILL MOVE THRU TUE NGT AND
BECOME STATIONARY NEAR THE NEB-KS BORDER WED-THU. IT MAY HEAD BACK N
TO NEAR THE NEB-SD BORDER FRI-SAT. THE DRYLINE WILL INTERSECT THIS
FRONT JUST W OF THE FCST AREA.
MODELS: 00Z GEM / 12Z AND 00Z EC / 18Z AND 00Z GFS / 12Z AND 00Z
UKMET ARE IN GOOD AGREEMENT ON THE OVERALL THEME THRU 00Z/SAT...
DEAMPLIFICATION TO ZONAL FLOW THEN A MODEST AMPLITUDE TROF MOVING
INTO THE WRN USA NEXT WEEKEND. TYPICAL TIMING DIFFERENCES BEGIN TO
SHOW UP NEXT SAT WITH THE 00Z GFS FASTER THAN ALL THE OTHER GUIDANCE
/AND EVEN ITS 18Z RUN/ ADVANCING THE TROF INTO THE ROCKIES.
HAZARDS: NOTHING DEFINABLE AT THIS POINT BUT MULTIPLE CHANCES FOR
TSTMS EXIST TUE NGT-SAT. IT/S TOO EARLY TO PIN DOWN LOCATION/TIMING/
COVERAGE AND INTENSITY...BUT ODDS ARE INCREASING THAT WE COULD HAVE
TO DEAL WITH AT LEAST ONE EPISODE OF SEVERE.
THE DAILY DETAILS...
MON: THE WARM FRONT WILL BISECT THE FCST AREA AT DAYBREAK. ANY
FRONTAL CLOUDS WILL CLEAR THE AREA AS THE FRONT DEPARTS TO THE E.
THIS WILL RESULT IN A SUNNY VERY WARM DAY...BUT W OF HWY 281 IT WILL
BE HOT /90-95F/. +24C AT H8 AND 582 HGTS AT H5.
TUE: SUNNY AND HOT. 93-98F. +26C AT H8 AND 582 HGTS AT H5. H8 TEMPS
2 STANDARD DEVIATIONS ABOVE NORMAL. HIGHS WILL BE 25F ABOVE NORMAL.
GRI AND HSI WILL BE WITHIN ABOUT 4F OF RECORD HIGHS BUT THEY SHOULD
BE SAFELY OUT OF REACH. GRI 99-1941. HSI 97-1941.
TUE NGT: COOL FRONTAL PASSAGE. IT/S PROBABLY DRY MOST LOCATIONS. AN
ISOLATE TSTM IS POSSIBLE.
WHILE THIS COOL FRONT WILL END THE HEAT...TEMPS WILL STILL REMAIN
8-15F ABOVE NORMAL WED-SAT.
WED: POSSIBLY A LEFT OVER SHWR OR TSTM ALONG THE FRONT?
THU-SAT: OVERALL SHOULD AVERAGE P/CLOUDY AND DRY MOST OF THE TIME.
HOWEVER...MULTIPLE EPISODES OF TSTMS APPEAR POSSIBLE ALONG THE
FRONT/DRYLINE.
OF PARTICULAR INTEREST IS THE RISING HGTS OVER THE ERN USA. THIS
WILL PREVENT TUE NGT/S COOL FRONT FROM PENETRATING FAR TO THE S.
HIGH PRES WILL PARK ITSELF OFF THE CAROLINA/S...SETTING UP SEVERAL
DAYS OF UNINTERRUPTED RICH GULF MSTR FLUX N INTO THE PLAINS. BY WED
AFTN H8 DWPTS OF 8+C WILL BE IN PLACE WITH SFC DWPTS INTO THE 50S
THU AND AROUND 60 FRI-SAT. DIURNAL OSCILLATIONS IN THE LLJ WILL
PROBABLY TRIGGER MCS ACTIVITY OVER THE NRN/CNTRL PLAINS.
SEVERE: AM GROWING INCREASINGLY CONCERNED ABOUT THE POTENTIAL FOR A
COUPLE EPISODES OF SVR TSTMS IN THE THU-MON TIME FRAME. THU-SAT
WOULD PROBABLY TAKE THE FORM OF A FORWARD PROPAGATING MCS. SUN COULD
BE SUBSTANTIALLY MORE INTERESTING AS THE LFQ OF A 120 KT ULJ EJECTS
INTO THE CNTRL PLAINS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1231 AM CDT SUN MAY 12 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF VALID PERIOD. THE WIND
WILL REMAIN OUT OF THE SOUTHEAST. THERE IS A SLIGHT CHANCE OF A
FEW SPRINKLES AROUND DAWN...BUT NOTHING SIGNIFICANT ENOUGH TO
WARRANT BEING PLACED IN THE TAF.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...FROST ADVISORY UNTIL 9 AM CDT THIS MORNING FOR NEZ039>041-048-
049-064.
KS...NONE.
&&
$$
SHORT TERM...WESELY
LONG TERM...HALBLAUB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
148 AM EDT SUN MAY 12 2013
.SYNOPSIS...
A SLOW-MOVING UPPER LEVEL LOW PRESSURE SYSTEM WILL MOVE EASTWARD
FROM THE GREAT LAKES FOR SUNDAY AND MONDAY...BRINGING THE CHANCE
FOR A FEW ISOLATED RAIN SHOWERS. THE AIR MASS WILL BE COLD ENOUGH
TO SUPPORT A FEW SNOW SHOWERS IN THE ADIRONDACKS DURING SUNDAY
NIGHT. CLEARING SKIES ARE EXPECTED MONDAY NIGHT AS A SURFACE RIDGE
CRESTS OVER THE NORTH COUNTRY. ASSOCIATED LIGHT WINDS WILL BRING
THE POSSIBILITY FOR PATCHY FROST DURING MONDAY NIGHT AS
TEMPERATURES FALL BACK INTO THE LOW TO MID 30S. A GRADUAL
MODERATING TREND IS EXPECTED BEGINNING TUESDAY AND THROUGH THE
MIDDLE OF NEXT WEEK. AN APPROACHING WARM FRONT MAY BRING
ADDITIONAL SHOWERS LATE WEDNESDAY INTO WEDNESDAY NIGHT.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
AS OF 113 AM EDT SUNDAY...MOSTLY CLOUDY SKIES CONTINUE TONIGHT
WITH THE NORTH COUNTRY UNDER WEAK SFC RIDGING IN THE WAKE OF THE
COLD FRONT THAT PASSED THROUGH EARLIER. THE MORE SIGNIFICANT COLD
FRONT IS NOW ENTERING FAR WESTERN NEW YORK STATE AND IS MOVING
QUICKLY EASTWARD AIDED BY A 70-KT MID-LEVEL JET MAX. THE FRONTAL
POSITION IS PRETTY EVIDENT IN IR SATELLITE IMAGERY BY A LINE OF
COOLER CLOUD TOP TEMPERATURES. GIVEN THE FASTER FRONTAL APPROACH
HAVE SPED UP THE TIMING OF THE FRONT BY A COUPLE HOURS BRINGING IT
INTO THE SAINT LAWRENCE VALLEY AROUND SUNRISE. INTRODUCED A SLIGHT
CHANCE OF SHOWERS BASED ON RADAR AND SFC OBSERVATIONAL TRENDS AND
RECENT RAP MODEL OUTPUT. WINDS ALSO WILL BEGIN TO PICK UP FROM THE
SOUTHWEST IN THE SAINT LAWRENCE VALLEY. THE REST OF THE NORTH
COUNTRY WILL BE CLOUDY BUT DRY THROUGH THE REST OF THE OVERNIGHT.
NO CHANGES TO LOW TEMPERATURES...GENERALLY IN THE 40S TO AROUND 50
DEGREES.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH MONDAY NIGHT/...
AS OF 337 PM EDT SATURDAY...UPPER-LEVEL LOW ACROSS THE GREAT
LAKES REGION TONIGHT AMPLIFIES AS IT SHIFTS EWD WITH LOW CENTER
ACROSS SERN ONTARIO AT 18Z SUNDAY...AND THEN LIFTS NEWD ACROSS
SRN QUEBEC DURING THE DAY MONDAY. MAIN IMPACT WILL BE COOLER
TEMPERATURES ACROSS THE NORTH COUNTRY WITH THIS FEATURE.
SECONDARY FRONTAL BNDRY CROSSES THE REGION FROM W-E DURING SUNDAY
AFTN AND MAY BRING ISOLD/SCATTERED LIGHT RAIN SHOWERS. MOST OF
THIS ACTIVITY WILL BE HIT OR MISS AND KEPT POPS GENERALLY ON THE
LOW SIDE (20-30 PERCENT). STEEP LAPSE RATES AND MODERATE GRADIENT
FLOW COULD YIELD SOME WIND GUSTS 35-40 MPH ACROSS THE NRN
ADIRONDACKS AND ST. LAWRENCE VALLEY. SHOULD REMAIN BELOW WIND
ADVISORY CRITERIA...BUT WILL BE BREEZY FOR MUCH OF SUNDAY
AFTN...ESPECIALLY ACROSS NRN NY. HIGHS SUNDAY AFTN GENERALLY IN
THE LOW-MID 50S ACROSS NRN NY...BUT INTO THE LOWER 60S FOR THE
VALLEYS OF VT...AND CLOSER TO 64-65F IN THE CT RIVER VALLEY.
ADDITIONAL LOW-LEVEL COLD ADVECTION SUNDAY NIGHT BRINGS 850MB
TEMPS OF -7 TO -8C ACROSS LAKE ONTARIO WITH SUFFICIENT LAKE
INDUCED INSTABILITY TO GENERATE SOME LAKE EFFECT RAIN/SNOW
SHOWERS DURING SUNDAY NIGHT. HAVE INDICATED A REGION OF 40-60
POPS ACROSS SRN ST. LAWRENCE INTO SRN FRANKLIN COUNTY NY DURING
SUNDAY NIGHT TO ACCOUNT FOR THIS LAKE EFFECT ACTIVITY. COULD SEE
A LIGHT COATING OF SNOW IN THE ADIRONDACKS 06-12Z MONDAY WITH
LOWS AROUND 30-32F. ELSEWHERE...NOT MUCH FORCING FOR ASCENT...SO
REMAINDER OF THE FORECAST AREA SHOULD BE DRY WITH LOWS IN THE MID
30S. ENOUGH GRADIENT WIND IN THE CHAMPLAIN VALLEY SHOULD PRECLUDE
ANY FROST POTENTIAL FOR SUNDAY NIGHT WHERE THE GROWING SEASON IS
CONSIDERED ACTIVE.
ON MONDAY...MID-LEVEL TROUGH AXIS SHIFTS EWD ACROSS THE REGION
WITH 850MB TEMPS AROUND -4C. SHOULD BE THE COOLEST DAY OF THE
STRETCH WITH VALLEY HIGH TEMPERATURES MONDAY ONLY IN THE LOW-MID
50S. STEEP LAPSE RATES MAY YIELD A FEW SHOWERS WITH DAYTIME
HEATING...ESPECIALLY OVER THE NRN MTNS. OTHERWISE...ANTICIPATE A
MIX OF SUN AND CLOUDS ACROSS THE REGION.
SFC RIDGE AXIS CRESTS OVERHEAD DURING MONDAY NIGHT WITH
ASSOCIATED LIGHT WINDS AND CLEARING SKIES. GROWING SEASON IS
UNDERWAY IN THE CHAMPLAIN VALLEY...AND ANTICIPATE PATCHY FROST
FORMATION WITH LOWS 33-35F THAT MAY REQUIRE COVERING OF TENDER
VEGETATION. HAVE INCLUDED MENTION IN THE HAZARDOUS WEATHER
OUTLOOK AND IN THE FORECAST AT THIS TIME.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 430 PM EDT SATURDAY...PROGRESSIVE UPPER LEVEL FLOW SETS UP
ACROSS THE NORTH COUNTRY FOR THE TUESDAY THROUGH SATURDAY TIME
FRAME. THERE WILL BE SEVERAL CHANCES FOR SHOWERS AS BLOCKING
PATTERN SETS UP TO OUR EAST AND WILL CAUSE SEVERAL SHORTWAVES TO
CROSS OUR FORECAST AREA. DEVELOPING OMEGA BLOCK OVER THE NORTH
CENTRAL ATLANTIC OCEAN AND HEAT RIDGE ACROSS SOUTHEASTERN UNITED
STATES KEEPS NORTHEAST US RIGHT ALONG THE PERIPHERY OF A BUILDING
UPPER RIDGE. IN THE THU-SAT TIME FRAME A LOW PRESSURE SYSTEM WILL
PASS NORTH OF THE REGION AND BRING CHANCE FOR SHOWERS TO THE AREA.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
THROUGH 06Z MONDAY...COLD FRONT APPROACHING FROM THE WEST THIS
MORNING WITH SOME MVFR CIGS AND LIGHT RA OR DZ SPOTTY ALONG THE
FRONT. MVFR CONDITIONS MAINLY TO AFFECT KMSS AND KSLK WITH THE
FRONT...WITH KMPV AND KRUT EXPERIENCING SOME MVFR CIGS ASSOCIATED
WITH MOISTURE FROM YESTERDAYS FRONTAL SYSTEM. BEHIND THE FRONT
WILL SEE FEW BREAKS...WITH VFR CIGS AT ALL TAF SITES FOR AT LEAST
A FEW HRS IN THE LATE MORNING. OTHERWISE...SW FLOW WILL KEEP
MOISTURE STREAMING OVER KSLK...WITH MVFR CIGS EXPECTED ONCE AGAIN
IN THE AFTN...WHILE REST OF THE TAF SITES EXPERIENCE VFR
CONDITIONS.
OF CONCERN WILL BE WINDS AND WIND GUSTS. AROUND AND BEHIND THE
FRONT...SW-WSW FLOW WILL DEVELOP WITH WIND SPEEDS OF 8-16 KTS AND
GUSTS OF 20-35 KTS DEVELOPING THIS MORNING...INCREASING IN THE
AFTN AND EARLY EVENING HRS. GUSTS WILL LIKELY SUBSIDE A BIT AFTER
SUNSET...BUT BREEZY CONDITIONS WILL CONTINUE INTO THE OVERNIGHT.
OUTLOOK 06Z MONDAY THROUGH THURSDAY...
06Z MONDAY THROUGH 00Z TUESDAY...MAINLY VFR THOUGH SPOTTY
INSTABILITY-DRIVEN LIGHT SHOWERS COULD PRODUCE PERIODS OF MVFR.
00Z TUESDAY THROUGH 12Z WEDNESDAY...VFR UNDER HIGH PRESSURE.
12Z WEDNESDAY THROUGH THURSDAY...VFR WITH MVFR PSBL WITHIN SCT
SHOWERS.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...EVENSON/LOCONTO
SHORT TERM...BANACOS
LONG TERM...NEILES
AVIATION...KGM
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
113 AM EDT SUN MAY 12 2013
.SYNOPSIS...
A SLOW-MOVING UPPER LEVEL LOW PRESSURE SYSTEM WILL MOVE EASTWARD
FROM THE GREAT LAKES FOR SUNDAY AND MONDAY...BRINGING THE CHANCE
FOR A FEW ISOLATED RAIN SHOWERS. THE AIR MASS WILL BE COLD ENOUGH
TO SUPPORT A FEW SNOW SHOWERS IN THE ADIRONDACKS DURING SUNDAY
NIGHT. CLEARING SKIES ARE EXPECTED MONDAY NIGHT AS A SURFACE RIDGE
CRESTS OVER THE NORTH COUNTRY. ASSOCIATED LIGHT WINDS WILL BRING
THE POSSIBILITY FOR PATCHY FROST DURING MONDAY NIGHT AS
TEMPERATURES FALL BACK INTO THE LOW TO MID 30S. A GRADUAL
MODERATING TREND IS EXPECTED BEGINNING TUESDAY AND THROUGH THE
MIDDLE OF NEXT WEEK. AN APPROACHING WARM FRONT MAY BRING
ADDITIONAL SHOWERS LATE WEDNESDAY INTO WEDNESDAY NIGHT.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
AS OF 113 AM EDT SUNDAY...MOSTLY CLOUDY SKIES CONTINUE TONIGHT
WITH THE NORTH COUNTRY UNDER WEAK SFC RIDGING IN THE WAKE OF THE
COLD FRONT THAT PASSED THROUGH EARLIER. THE MORE SIGNIFICANT COLD
FRONT IS NOW ENTERING FAR WESTERN NEW YORK STATE AND IS MOVING
QUICKLY EASTWARD AIDED BY A 70-KT MID-LEVEL JET MAX. THE FRONTAL
POSITION IS PRETTY EVIDENT IN IR SATELLITE IMAGERY BY A LINE OF
COOLER CLOUD TOP TEMPERATURES. GIVEN THE FASTER FRONTAL APPROACH
HAVE SPED UP THE TIMING OF THE FRONT BY A COUPLE HOURS BRINGING IT
INTO THE SAINT LAWRENCE VALLEY AROUND SUNRISE. INTRODUCED A SLIGHT
CHANCE OF SHOWERS BASED ON RADAR AND SFC OBSERVATIONAL TRENDS AND
RECENT RAP MODEL OUTPUT. WINDS ALSO WILL BEGIN TO PICK UP FROM THE
SOUTHWEST IN THE SAINT LAWRENCE VALLEY. THE REST OF THE NORTH
COUNTRY WILL BE CLOUDY BUT DRY THROUGH THE REST OF THE OVERNIGHT.
NO CHANGES TO LOW TEMPERATURES...GENERALLY IN THE 40S TO AROUND 50
DEGREES.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH MONDAY NIGHT/...
AS OF 337 PM EDT SATURDAY...UPPER-LEVEL LOW ACROSS THE GREAT
LAKES REGION TONIGHT AMPLIFIES AS IT SHIFTS EWD WITH LOW CENTER
ACROSS SERN ONTARIO AT 18Z SUNDAY...AND THEN LIFTS NEWD ACROSS
SRN QUEBEC DURING THE DAY MONDAY. MAIN IMPACT WILL BE COOLER
TEMPERATURES ACROSS THE NORTH COUNTRY WITH THIS FEATURE.
SECONDARY FRONTAL BNDRY CROSSES THE REGION FROM W-E DURING SUNDAY
AFTN AND MAY BRING ISOLD/SCATTERED LIGHT RAIN SHOWERS. MOST OF
THIS ACTIVITY WILL BE HIT OR MISS AND KEPT POPS GENERALLY ON THE
LOW SIDE (20-30 PERCENT). STEEP LAPSE RATES AND MODERATE GRADIENT
FLOW COULD YIELD SOME WIND GUSTS 35-40 MPH ACROSS THE NRN
ADIRONDACKS AND ST. LAWRENCE VALLEY. SHOULD REMAIN BELOW WIND
ADVISORY CRITERIA...BUT WILL BE BREEZY FOR MUCH OF SUNDAY
AFTN...ESPECIALLY ACROSS NRN NY. HIGHS SUNDAY AFTN GENERALLY IN
THE LOW-MID 50S ACROSS NRN NY...BUT INTO THE LOWER 60S FOR THE
VALLEYS OF VT...AND CLOSER TO 64-65F IN THE CT RIVER VALLEY.
ADDITIONAL LOW-LEVEL COLD ADVECTION SUNDAY NIGHT BRINGS 850MB
TEMPS OF -7 TO -8C ACROSS LAKE ONTARIO WITH SUFFICIENT LAKE
INDUCED INSTABILITY TO GENERATE SOME LAKE EFFECT RAIN/SNOW
SHOWERS DURING SUNDAY NIGHT. HAVE INDICATED A REGION OF 40-60
POPS ACROSS SRN ST. LAWRENCE INTO SRN FRANKLIN COUNTY NY DURING
SUNDAY NIGHT TO ACCOUNT FOR THIS LAKE EFFECT ACTIVITY. COULD SEE
A LIGHT COATING OF SNOW IN THE ADIRONDACKS 06-12Z MONDAY WITH
LOWS AROUND 30-32F. ELSEWHERE...NOT MUCH FORCING FOR ASCENT...SO
REMAINDER OF THE FORECAST AREA SHOULD BE DRY WITH LOWS IN THE MID
30S. ENOUGH GRADIENT WIND IN THE CHAMPLAIN VALLEY SHOULD PRECLUDE
ANY FROST POTENTIAL FOR SUNDAY NIGHT WHERE THE GROWING SEASON IS
CONSIDERED ACTIVE.
ON MONDAY...MID-LEVEL TROUGH AXIS SHIFTS EWD ACROSS THE REGION
WITH 850MB TEMPS AROUND -4C. SHOULD BE THE COOLEST DAY OF THE
STRETCH WITH VALLEY HIGH TEMPERATURES MONDAY ONLY IN THE LOW-MID
50S. STEEP LAPSE RATES MAY YIELD A FEW SHOWERS WITH DAYTIME
HEATING...ESPECIALLY OVER THE NRN MTNS. OTHERWISE...ANTICIPATE A
MIX OF SUN AND CLOUDS ACROSS THE REGION.
SFC RIDGE AXIS CRESTS OVERHEAD DURING MONDAY NIGHT WITH
ASSOCIATED LIGHT WINDS AND CLEARING SKIES. GROWING SEASON IS
UNDERWAY IN THE CHAMPLAIN VALLEY...AND ANTICIPATE PATCHY FROST
FORMATION WITH LOWS 33-35F THAT MAY REQUIRE COVERING OF TENDER
VEGETATION. HAVE INCLUDED MENTION IN THE HAZARDOUS WEATHER
OUTLOOK AND IN THE FORECAST AT THIS TIME.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 430 PM EDT SATURDAY...PROGRESSIVE UPPER LEVEL FLOW SETS UP
ACROSS THE NORTH COUNTRY FOR THE TUESDAY THROUGH SATURDAY TIME
FRAME. THERE WILL BE SEVERAL CHANCES FOR SHOWERS AS BLOCKING
PATTERN SETS UP TO OUR EAST AND WILL CAUSE SEVERAL SHORTWAVES TO
CROSS OUR FORECAST AREA. DEVELOPING OMEGA BLOCK OVER THE NORTH
CENTRAL ATLANTIC OCEAN AND HEAT RIDGE ACROSS SOUTHEASTERN UNITED
STATES KEEPS NORTHEAST US RIGHT ALONG THE PERIPHERY OF A BUILDING
UPPER RIDGE. IN THE THU-SAT TIME FRAME A LOW PRESSURE SYSTEM WILL
PASS NORTH OF THE REGION AND BRING CHANCE FOR SHOWERS TO THE AREA.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
THROUGH 00Z MONDAY...VFR CONDITIONS WILL START THE PERIOD WITH A
TREND TOWARD VFR/MVFR CEILINGS WITH QUITE A BIT OF CLOUD COVER
UPSTREAM. VISIBILITIES WILL REMAIN IN THE VFR CATEGORY THROUGH THE
PERIOD. WEST TO SOUTHWEST WINDS WILL DIMINISH A BIT OVERNIGHT...THEN
INCREASE A LITTLE ON SUNDAY WITH STRONGER WIND GUSTS OVER THE SAINT
LAWRENCE VALLEY OF NEW YORK AFTER 18Z...GENERALLY IN THE 25 TO 35
KNOT RANGE.
OUTLOOK 00Z MONDAY THROUGH WEDNESDAY...
00Z MONDAY THROUGH 00Z TUESDAY...MAINLY VFR THOUGH SPOTTY
INSTABILITY-DRIVEN LIGHT SHOWERS COULD PRODUCE MVFR PERIODS.
00Z TUESDAY THROUGH THURSDAY...VFR UNDER HIGH PRESSURE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...EVENSON/LOCONTO
SHORT TERM...BANACOS
LONG TERM...NEILES
AVIATION...EVENSON/NEILES
AREA FORECAST DISCUSSION
NWS TULSA OK
1239 PM CDT SUN MAY 12 2013
.DISCUSSION...
LARGE UPPER TROUGH OVER THE EASTERN CONUS CONTINUES TO SHIFT EAST
TODAY. NW FLOW ALOFT PREVAILS OVER THE PLAINS IN BETWEEN THE
TROUGH TO THE EAST AND THE AMPLIFYING RIDGE OVER THE WEST. HIGH
BASED SHOWERS AND EVEN A FEW RUMBLES OF THUNDER ARE OBSERVED TO
OUR NORTH AND WEST...MOST LIKELY DUE TO MID LVL WARM
ADVECTION/FRONTOGENESIS ALONG THE NW FLOW BAROCLINIC ZONE. WILL
MONITOR LIGHTNING ACTIVITY TO SEE IF THUNDER NEEDS TO BE INSERTED
INTO THE GRIDS. CURRENT FORECAST 20 POP FOR SHOWERS OVER NE OK AND
NW AR LOOKS GOOD BASED ON RECENT HRRR MODEL DATA. NO MAJOR CHANGES
HAVE BEEN REQUIRED TO THE GOING FORECAST.
LACY
&&
.PREV DISCUSSION... /ISSUED 1207 PM CDT SUN MAY 12 2013/
DISCUSSION...
THE 18Z TAF DISCUSSION CAN BE FOUND BELOW.
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VFR CONDITIONS WILL PREVAIL WITH SCT TO BKN MID CLOUDS AOA 10KFT.
ISOLD TO WDLY SCT SHRA COULD BE NEAR THE NE OK AND NW AR TAF SITES
THIS AFTERNOON SO INSERTED VCSH. LIGHT WINDS TODAY WILL SWITCH TO
SOUTHWEST AND BECOME GUSTY AFT 15Z MONDAY AS LEE TROF DVLPS ON THE
HI PLNS.
LACY
PREV DISCUSSION... /ISSUED 542 AM CDT SUN MAY 12 2013/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VFR CONDITIONS EXPECTED THROUGH THE PERIOD...WITH INCREASING MID
CLOUDS EXPECTED DURING THE AFTERNOON. SMALL CHANCE OF SHRA ACROSS
NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS...BUT CONFIDENCE AND
EXPECTED COVERAGE LOW ENOUGH TO NOT INCLUDE ATTM.
PREV DISCUSSION... /ISSUED 304 AM CDT SUN MAY 12 2013/
DISCUSSION...
COOL START THIS MORNING AS SURFACE HIGH PRESSURE CONTINUES TO
BUILD INTO THE REGION WITH MOSTLY CLEAR SKIES/NORTHWEST FLOW
ALOFT. WEAK UPPER LEVEL DISTURBANCE WILL DIVE SOUTH INTO THE
AREA TODAY WITH INCREASING MID CLOUDS AND THE POTENTIAL FOR A FEW
ISOLATED/WIDELY SCATTERED SHOWERS INTO THE AFTERNOON HOURS. THIS
WILL KEEP HIGH TEMPERATURES ON THE MILD SIDE...ESPECIALLY ACROSS
FAR NORTHEAST OKLAHOMA/NORTHWEST ARKANSAS WHERE THE CLOUD COVER IS
EXPECTED TO BE THE THICKEST/MORE WIDESPREAD.
WARMING TREND WILL DEVELOP MONDAY AS UPPER RIDGE QUICKLY BUILDS
INTO THE PLAINS WITH UNSEASONABLY WARM/BREEZY CONDITIONS TUESDAY
AS GUSTY SOUTHWEST WINDS DEVELOP. UPPER LOW...CURRENTLY OVER THE
BAJA OF MEXICO...WILL LIFT INTO OKLAHOMA ON WEDNESDAY WITH SCATTERED
SHOWERS/THUNDERSTORMS POSSIBLE. PRECIPITATION CHANCES WILL LINGER
INTO THURSDAY BEFORE UPPER LOW WEAKENS/SHIFTS EAST OF THE AREA BY
FRIDAY.
SLOW WARMING TREND RETURNS INTO THE WEEKEND AS UPPER RIDGE BUILDS
BACK INTO THE SOUTHERN PLAINS. PRECIPITATION CHANCES APPEAR TO BE
LIMITED WITH MILD NIGHTS/WARM AFTERNOONS EXPECTED BOTH FRIDAY AND
SATURDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 51 85 63 86 / 10 10 0 10
FSM 50 83 57 87 / 10 10 0 10
MLC 52 85 62 86 / 10 10 0 0
BVO 48 83 56 87 / 10 10 10 10
FYV 43 78 56 83 / 10 10 0 10
BYV 46 78 57 86 / 10 10 0 10
MKO 50 83 60 86 / 10 10 0 10
MIO 47 81 58 86 / 10 10 10 10
F10 52 85 62 85 / 10 10 0 10
HHW 51 83 60 84 / 10 10 0 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...30
AREA FORECAST DISCUSSION
NWS PORTLAND OR
855 AM PDT SUN MAY 12 2013
.SYNOPSIS...A FRONTAL SYSTEM NEAR THE COAST WILL WEAKEN AND DISSIPATE
AS IT MOVES ACROSS THE AREA TODAY. THE BULK OF THE RAINFALL WITH THIS
SYSTEM WILL REMAIN WELL TO THE NORTH...BUT WILL LIKELY CONTINUE TO
SEE SOME LIGHT PRECIP IN OUR NORTHERN ZONES TODAY. A REINFORCING
UPPER LEVEL SHORTWAVE WILL BRING MORE WIDESPREAD AND HEAVIER RAIN TO
THE REGION MONDAY. A FEW THUNDERSTORMS MAY DEVELOP ACROSS THE
NORTHERN ZONES ON MONDAY AS WELL. SEVERAL WEAK STORM SYSTEMS WILL
SKIRT THE REGION NEXT WEEK BRINGING CLOUDS...PERIODIC SHOWER
ACTIVITY AND TEMPERATURES NEAR SEASONAL NORMALS.
&&
.SHORT TERM...THE STRONG RIDGE OF HIGH PRESSURE THAT DOMINATED THE
WEATHER OVER THE PACNW FOR THE PAST SEVERAL DAYS HAS MOVED EASTWARD.
NEAR THE COAST...A FRONTAL SYSTEM WILL WEAKEN AND DISSIPATE AS IT
PUSHES INLAND TODAY. MOST OF THE ENERGY AND HEAVIER PRECIP WITH THIS
FRONT CONTINUES TO BE AIMED WELL TO THE NORTH TOWARD BC AND THE
OLYMPIC PENINSULA. THE HRRR MODEL SHOWS THE FRONT DISSIPATING AS IT
MOVES OVER THE COAST RANGE...WITH ANY SIGNIFICANT PRECIP MAINLY
AFFECTING THE NORTH COAST AND THE SOUTH WA AND NORTH OR CASCADES AND
FOOTHILLS. GIVEN THE RECENT WARM AIRMASS THERE MAY BE ENOUGH ENERGY
TO ENHANCE SHOWER ACTIVITY THIS AFTERNOON ACROSS THE INTERIOR AS WHAT
REMAINS OF THE FRONT MOVES THROUGH.
A MORE POTENT SHORTWAVE WILL MOVE INTO THE REGION ON MONDAY. THIS
SYSTEM WILL DROP FURTHER SOUTH...WITH THE BASE OF THE TROUGH MOVING
THROUGH OREGON. THIS TRACK WOULD RESULT IN SIGNIFICANTLY MORE FORCING
OVER SW WASHINGTON AND NW OREGON WITH INCREASED WESTERLY OROGRAPHIC
FLOW. SO...MONDAY APPEARS TO HOLD A MUCH BETTER SHOT FOR RECEIVING
SOME DECENT RAINFALL ACROSS OUR DISTRICT. MODELS ALSO SHOW QUITE
A BIT OF INSTABILITY FROM ABOUT SALEM NORTHWARD ON MONDAY
AFTERNOON...SO THERE IS ALSO A THREAT OF THUNDERSTORM ACTIVITY
MONDAY AFTERNOON INTO THE EARLY EVENING HOURS.
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
TUE THROUGH FRIDAY...AFTER THE SYSTEM ON MON PASSES THROUGH...THE PAC
NW WILL BE LEFT IN A RELATIVELY ZONAL PATTERN FOR THE REST OF THE
WEEK. A COUPLE OF WEAK TROUGHS ARE DEPICTED MOVING THROUGH THE UPPER
FLOW...SO WE WILL HAVE THE POTENTIAL FOR SOME SOME PERIODIC SHOWER
ACTIVITY. HOWEVER...NOTHING VERY WELL ORGANIZED IS EXPECTED.
OTHERWISE...EXPECT CLOUDS AND COOLER MORE SEASONAL TEMPS FOR NEXT
WEEK. PYLE
&&
.AVIATION...A COLD FRONT IS SLOWLY PUSHING ONSHORE THIS MORNING.
EXPECT LIGHT SHOWERS AND PERIODS OF MVFR CIGS AS THE FRONT SLOWLY
MOVES THROUGH...ESPECIALLY THROUGH ABOUT 20Z. CHANCES FOR MORE
WIDESPREAD MVFR INCREASE THIS EVENING AS THE WINDS TURN MORE
SOUTHWESTERLY. A STRONGER FRONT WILL MOVE IN OVERNIGHT INTO
MON...BRINGING HEAVIER RAIN AND LOWERED CIGS.
KPDX AND APPROACHES...EXPECT PERIODIC LIGHT RAIN AND MVFR CIGS
TODAY AS A WEAK FRONT SLOWLY PUSHES THROUGH. A STRONGER FRONT WILL
BRING HEAVIER RAIN AND PREDOMINANTLY MVFR CIGS BETWEEN 12Z AND 18Z
TOMORROW MORNING. PYLE
&&
.MARINE...A WEAK COLD FRONT IS PUSHING INLAND THIS MORNING. WINDS
ARE RUNNING LOWER THAN THE MODELS ARE SUGGESTING...SO DECIDED TO
END THE SMALL CRAFT ADVISORY FOR WINDS THIS MORNING. A STRONGER
WAVE WILL MOVE ALONG THE FRONTAL BOUNDARY ON TOMORROW MORNING AND
MON...WHICH SHOULD BRING A MORE SOLID SMALL CRAFT ADVISORY EVENT.
SEAS SHOULD REMAIN 4 TO 6 FT RANGE TODAY THEN INCREASE FURTHER
WITH THE SYSTEM ON MON...POTENTIALLY REACHING NEAR 10 FT LATE MON.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS PORTLAND OR
310 AM PDT SUN MAY 12 2013
.SYNOPSIS...A FRONTAL SYSTEM NEAR THE COAST WILL WEAKEN AND DISSIPATE
AS MOVES ACROSS THE AREA TODAY. THE BULK OF THE RAINFALL WITH THIS
SYSTEM WILL REMAIN WELL TO THE NORTH...BUT WILL LIKELY SEE SOME LIGHT
PRECIP IN OUR NORTHERN ZONES TODAY. A REINFORCING UPPER LEVEL
SHORTWAVE WILL BRING MORE WIDESPREAD AND HEAVIER RAIN TO THE REGION
MONDAY. A FEW THUNDERSTORMS MAY DEVELOP ACROSS THE NORTHERN ZONES ON
MONDAY AS WELL. SEVERAL WEAK STORM SYSTEMS WILL SKIRT THE REGION NEXT
WEEK BRINGING CLOUDS...PERIODIC SHOWER ACTIVITY AND TEMPERATURES NEAR
SEASONAL NORMALS.
&&
.SHORT TERM...THE STRONG RIDGE OF HIGH PRESSURE THAT DOMINATED THE
WEATHER OVER THE PACNW FOR THE PAST SEVERAL DAYS HAS MOVED EASTWARD.
NEAR THE COAST...A FRONTAL SYSTEM WILL WEAKEN AND DISSIPATE AS IT
PUSHES INLAND TODAY. MOST OF THE ENERGY AND HEAVIER PRECIP WITH THIS
FRONT CONTINUES TO BE AIMED WELL TO THE NORTH TOWARD BC AND THE
OLYMPIC PENINSULA. THE HRRR MODEL SHOWS THE FRONT DISSIPATING AS IT
MOVES OVER THE COAST RANGE...WITH ANY SIGNIFICANT PRECIP MAINLY
AFFECTING THE NORTH COAST AND THE SOUTH WA AND NORTH OR CASCADES AND
FOOTHILLS.
A MORE POTENT SHORTWAVE WILL MOVE INTO THE REGION ON MONDAY. THIS
SYSTEM WILL DROP FURTHER SOUTH...WITH THE BASE OF THE TROUGH MOVING
THROUGH OREGON. THIS TRACK WOULD RESULT IN SIGNIFICANTLY MORE FORCING
OVER SW WASHINGTON AND NW OREGON WITH INCREASED WESTERLY OROGRAPHIC
FLOW. SO...MONDAY APPEARS TO HOLD A MUCH BETTER SHOT FOR RECEIVING
SOME DECENT RAINFALL ACROSS OUR DISTRICT. MODELS ALSO SHOW QUITE
ABIT OF INSTABILITY FROM ABOUT SALEM NORTHWARD ON MONDAY
AFTERNOON...SO THERE IS ALSO A THREAT OF THUNDERSTORM ACTIVITY
MONDAY AFTERNOON INTO THE EARLY EVENING HOURS. TW
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
TUE THROUGH FRIDAY...AFTER THE SYSTEM ON MON PASSES THROUGH...THE PAC
NW WILL BE LEFT IN A RELATIVELY ZONAL PATTERN FOR THE REST OF THE
WEEK. A COUPLE OF WEAK TROUGHS ARE DEPICTED MOVING THROUGH THE UPPER
FLOW...SO WE WILL HAVE THE POTENTIAL FOR SOME SOME PERIODIC SHOWER
ACTIVITY. HOWEVER...NOTHING VERY WELL ORGANIZED IS EXPECTED.
OTHERWISE...EXPECT CLOUDS AND COOLER MORE SEASONAL TEMPS FOR NEXT
WEEK. PYLE
&&
.AVIATION...A COLD FRONT IS STALLED OFFSHORE THROUGH TONIGHT.
EXPECT SOME LIGHT RAIN AT TIMES ON THE COAST AND FAR NW OREGON AND
SW WASHINGTON. ON THE COAST...GENERALLY VFR CONDITIONS THIS
MORNING WITH OCCASIONAL MVFR CONDITIONS ESPECIALLY NORTH. CHANCES
FOR MORE WIDESPREAD MVFR INCREASE IN THE AFTERNOON AS THE WINDS
TURN MORE SOUTHWESTERLY. INLAND AREAS ARE EXPECTED TO REMAIN VFR
TODAY WITH MVFR CIGS POSSIBLE LATER TONIGHT.
KPDX AND APPROACHES...VFR EXPECTED THROUGH 06Z MON. AFTER THAT
MODELS ARE INDICATING INCREASING CHANCES FOR MVFR CIGS AROUND
2500-3000 FEET. BUT CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE MVFR
CONDITIONS IN THE 12Z TAFS.
&&
.MARINE...FRONT REMAINS OFFSHORE WITH SLOW EASTWARD PROGRESS AS
SEVERAL WAVES RIDE ALONG THE FRONT. MAIN CHANGES FOR TODAY IS TO
ADJUST TIMING OF THE MARGINAL SMALL CRAFT ADVISORY FOR THE
NORTHERN OUTER WATERS TO 5 AM TO 11 AM TODAY. A STRONGER WAVE WILL
MOVE ALONG THE FRONTAL BOUNDARY ON MON AND WILL PROBABLY BRING A
MORE SOLID SMALL CRAFT ADVISORY EVENT.
SEAS SHOULD REMAIN 4 TO 6 FT RANGE TODAY THEN INCREASE FURTHER
WITH THE SYSTEM ON MON...POTENTIALLY REACHING NEAR 10 FT LATE MON.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 5 AM TO 11 AM PDT THIS
MORNING FOR WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD
OR FROM 10 TO 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 5 AM
TO 9 AM PDT THIS MORNING.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION...UPDATED
NWS PENDLETON OR
1025 PM PDT SAT MAY 11 2013
UPDATED AVIATION DISCUSSION
.UPDATE...THE UPPER LEVEL HIGH PRESSURE RIDGE THAT HAS BROUGHT
UNSEASONABLY HOT CONDITIONS FOR SEVERAL DAYS IS SHIFTING
EASTWARD...AND THE UPPER FLOW IS BACKING TO THE SOUTHWEST. HIGH
LEVEL CLOUDS HAVE SPREAD THROUGHOUT WA/OR WHICH WILL KEEP
OVERNIGHT LOWS VERY MILD. LOW TEMPERATURES MAY NEED TO BE
INCREASED IN SEVERAL ZONES. FORECAST WAS UPDATED TO REMOVE
THUNDERSTORMS THIS EVENING EXCEPT IN THE HIGHER TERRAIN...BUT
THERE IS NO INDICATION OF ANY CONVECTIVE ACTIVITY SO WILL REMOVE
ALTOGETHER FOR THIS EVENING. HOWEVER...THERE WILL BE ELEVATED
INSTABILITY OVERNIGHT...AND THE HRRR AND OTHER RAP INSTABILITY
PARAMETERS HAVE HINTED ON SOME CONVECTIVE PRECIPITATION MOVING
ACROSS THE AREA. BASED ON PREVIOUS HRRR RUNS...I ADDED A SLIGHT
CHANCE OF THUNDERSTORMS OVERNIGHT TO CENTRAL AND NORTH CENTRAL
OREGON AND SPRINKLES TO THE LOWER COLUMBIA BASIN AND BLUE MOUNTAIN
FOOTHILLS EARLY SUNDAY MORNING. IT COULD BE ALTOCUMULUS
CASTELLANUS CLOUDS...BUT WILL NOT RULE OUT SOME VERY LIGHT
PRECIPITATION OR A HIGH BASED THUNDERSTORM OR TWO. THE LATEST HRRR
IS FARTHER WEST WITH THE SMALL BAND OF CONVECTIVE PCPN...BUT WILL
KEEP WHERE THE ELEVATED INSTABILITY IS GREATEST. WISTER
&&
.AVIATION...06Z TAFS. BROKEN MID AND HIGH LEVEL CLOUDS WITH VARYING
BASES ABOVE 10K FEET WILL BLANKET THE REGION THROUGH THE PERIOD.
DUE TO ELEVATED INSTABILITY...THERE WILL LIKELY BE ACCAS CLOUDS
EARLY SUNDAY MORNING. CUMULUS CLOUDS WITH BASES AROUND 6K FEET ARE
POSSIBLE SUNDAY AFTN/EVE. WINDS WILL INCREASE SUNDAY AND WILL BE
SUSTAINED AT 10-15 KNOTS GUSTING TO 20-25 KNOTS. THERE IS A SLIGHT
CHANCE OF THUNDERSTORMS OVER THE CENTRAL AND NORTHEAST MOUNTAINS
SUNDAY. WISTER
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 59 80 53 69 / 10 20 30 40
ALW 63 82 57 72 / 10 20 30 40
PSC 61 85 57 74 / 10 20 20 30
YKM 60 81 52 72 / 10 20 20 30
HRI 58 82 55 74 / 0 20 20 30
ELN 59 76 51 68 / 10 30 20 30
RDM 55 81 48 67 / 20 20 20 20
LGD 52 80 50 70 / 10 30 30 40
GCD 51 81 50 71 / 10 30 30 40
DLS 60 76 53 69 / 10 40 30 30
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
THREAT INDEX
SUNDAY : GREEN
MONDAY : YELLOW
TUESDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
85
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
256 PM MDT SUN MAY 12 2013
.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 255 PM MDT SUN MAY 12 2013
MASSIVE WESTERN CONUS UPPER RIDGE CONTINUES TO PUSH
EAST WITH DEEP LAYER THETA-E RIDGING ONGOING. LEE SIDE TROUGH
WILL ADVECT EAST AWAY FORM THE ROCKIES ON THE LEADING EDGE OF
UPPER LEVEL HEIGHT RISES...WITH A STRONG UPPER LEVEL TROUGH
EXPECTED TO ADVANCE INTO THE NORTHERN PLAINS MONDAY
NIGHT...SUPPORTING ANOTHER MORE PRONOUNCED LL TROUGH INTO THE
REGION. OVERALL...MAINLY DRY WEATHER EXPECTED...SAVE FOR PORTIONS
OF THE BLACK HILLS WHERE LL THETA-E ADV COUPLED WITH STEEPENING
MID LEVEL LAPSE RATES AND LOCAL OROGRAPHIC CONVERGENCE MAY
SUPPORT ISOLD SHRA/TS LATE THIS AFTERNOON/EARLY EVENING AND AGAIN
MONDAY AFTERNOON/EVENING. OTHERWISE...A SIG WARM NOSE ASSOCIATED
WITH THE ADVANCING RIDGE IS EXPECTED TO KEEP CONVECTION AT BAY
ELSEWHERE.
LATE THIS AFTERNOON/TONIGHT...REMOVED LOW POPS OVER THE
CENTRAL/SOUTHERN BH. NEARLY ALL HIRES MODELS DO NOT GENERATE ANY
CONVECTION...WITH THE NAM BEING THE ONLY MODEL/OUTLIER THAT DOES.
LATEST RAP BUFR PROGS INDICATE MID LEVEL WARMING IS STRONGER/FASTER
THAN PREVIOUS INDICATIONS...WITH A DOWNTREND IN CU NOTED IN SAT
TRENDS. OTHERWISE...A WARM NIGHT EXPECTED WITH LOWS IN THE 50S AT
MANY PLACES. THERE IS A SMALL POTENTIAL FOR AN ELEVATED SHOWER
ACROSS THE FAR NORTH GIVEN THETA-E ADV AT THE BASE OVER THE GROWING
WARM NOSE WITH NEGATIVE SW INDICES. HOWEVER...GIVEN THE LOW
POTENTIAL HAVE LEFT OUT AND WILL LET THE NEXT SHIFT ASSESS.
MONDAY...LEAD LL TROUGH WILL ADVECT EAST ACROSS THE AREA IN THE
MORNING...WITH ONGOING DEEP LAYER WAA. INCREASED LL MOISTURE MAY BE
SUFFICIENT ENOUGH TO GENERATE ISOLD CONVECTION OVER THE BH...ESP
WITH A WEAK MESO LOW AS INDICATED IN THE NAM. RETAINED SLIGHT CHANCE
POPS THERE. OTHERWISE...VERY WARM CONDITIONS EXPECTED WITH LOW TO
MID 90S OVER THE SD PLAINS...COOLER WEST. CURRENT FORECAST TEMPS
SURPASSES THE RECORD OF 92 AT THE RAPID CITY AIRPORT...NEARING THE
DOWNTOWN RECORD OF 94. A VERY WARM NIGHT IS IN STORE FOR MONDAY
NIGHT...WITH LOWS IN THE 60S AT MANY PLACES GIVEN ONGOING SFC
PRESSURE FALLS PER THE ADVANCING DEEP NORTHERN STREAM UPPER IMPULSE.
THIS WILL SUPPORT A MIXED BL WITH GUSTY WINDS POTENTIALLY AT MANY
LOCATIONS...ESP OVER THE NORTHERN BH FOOTHILLS...GIVEN A NEAR 5 MB
SFC PRESSURE DIFFERENTIAL FROM THE BH TO THE PLAINS. RECORD HIGH
MIN/S MAY BE SET AT RAPID CITY.
&&
.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 255 PM MDT SUN MAY 12 2013
UPPER LEVEL RIDGE BREAKS DOWN BY TUESDAY MORNING AS A SURFACE LOW
PASSES TO THE NORTH AND A STRONG COLD FRONT SLIDES QUICKLY ACROSS
THE FORECAST AREA DURING THE MORNING. STRONG NORTHWEST WINDS CAN BE
EXPECTED ACROSS THE NORTHWEST AND WEST CENTRAL SOUTH DAKOTA PLAINS
BEHIND THE FRONT. THE STRONGEST WINDS LOOK TO BE NEAR THE ND BORDER.
HAVE DECIDED TO ISSUE A HIGH WIND WATCH FOR HARDING AND PERKINS
COUNTIES...WHERE SUSTAINED WINDS OF 40 MPH OR MORE LOOK POSSIBLE...
ESPECIALLY DURING THE LATE MORNING AND EARLY AFTERNOON HOURS. HIGH
TEMPERATURES WILL RANGE FROM THE LOWER 70S OVER FAR NORTHWESTERN SD
AND PORTIONS OF NORTHEASTERN WY TO THE UPPER 80S ACROSS SOUTH
CENTRAL SD. DEPENDING ON THE EXACT TIMING OF THE FRONT AND HOW
QUICKLY THE DRIER AIR PUSHES IN BEHIND THE FRONT...THERE IS SOME
POTENTIAL FOR CRITICAL FIRE WEATHER CONDITIONS TO DEVELOP ACROSS
PORTIONS OF THE SD PLAINS TUESDAY AFTERNOON. WILL LET LATER SHIFTS
HAVE A LOOK AT UPDATED MODEL DAYA FOR THIS POTENTIAL AND WHETHER A
FIRE WX WATCH MAY BE NEEDED.
MORE SEASONABLE TEMPS ARE EXPECTED FOR THE REMAINDER OF THE
WEEK...THOUGH STILL ABOVE AVERAGE...AS AREA REMAINS UNDER ZONAL
FLOW. WEAK DISTURBANCES WITHIN THIS FLOW WILL BRING SOME CHANCES FOR
MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS LATE IN THE
WEEK...WITH CHANCES LIKELY INCREASING BY THE WEEKEND. LATEST GFS AND
ECMWF BOTH CONTINUE TO SHOW A STRONGER UPPER TROF IMPACTING THE
REGION FROM LATE FRIDAY THROUGH THE WEEKEND...BRINGING THE POTENTIAL
FOR MORE WIDESPREAD PCPN AND OUR FIRST SEVERE WX OF THE SEASON.
&&
.AVIATION...FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON
ISSUED AT 255 PM MDT SUN MAY 12 2013
VFR CONDITIONS ARE EXPECTED THROUGH MONDAY MORNING.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...HIGH WIND WATCH FROM TUESDAY MORNING THROUGH TUESDAY AFTERNOON
FOR SDZ001-002.
WY...NONE.
&&
$$
SHORT TERM...JC
LONG TERM...26
AVIATION...26
AREA FORECAST DISCUSSION
NWS SPOKANE WA
223 PM PDT Sun May 12 2013
.SYNOPSIS...
A cold front will arrive this evening, and bring breezy
conditions to much of the Inland Northwest. On Monday a vigorous
upper level disturbance will bring the first period of widespread
precipitation to the region in over three weeks with locally heavy
downpours and thunderstorms. The arrival of cooler, more seasonal
temperatures Tuesday through the upcoming weekend will allow many
rivers to recede.
&&
.DISCUSSION...
Tonight: There will be two features of note where showers will
focus through this evening into tonight. This first is a mid level
front that has stalled across northwest Oregon into north-central
Washington. We have seen some very light shower activity along the
eastern edge of this front and much of this precip is likely
evaporating before reaching the surface. Radar imagery showed some
enhancement over southwest Washington around 1:30 in the
afternoon indicating a bit more lift across this area possibly due
to a little ripple moving in. The HRRR model takes this
enhancement moves it northeast ward over Wenatchee to Colville
through this evening. As a result, I kept some minor mention of
showers along this area; however, I am not that confident that we
will generate much in the way of measurable rainfall along the front.
The second area of note is a ridge axis in the equivalent
potential temperature field between 850-700 mbs from northeast
Oregon, across the Central Panhandle and into western Montana.
Visible satellite imagery is showing signs of some surface based
convection beginning to fire along this axis and should continue
to develop through at least the early evening hours. There isn`t
much of a trigger coming through to keep convection going through
the night, but the mid level front looks to nudge a bit more
eastward this evening. This may be enough to keep showers going
through the evening from the Northeast Blue Mountains into the
Central Panhandle Mountains. I kept a mention of isolated
thunderstorms in these areas as sounding profiles would suggest
that it is possible. The HRRR model does show the possibility of
40+ dbz echoes as well, but I am not too excited for thunderstorms
this evening. /SVH
Monday and Monday night...This period promises to be a very active
weather period for much of the forecast area as a transition into
a much cooler and spring-like weather pattern arrives. Satellite
indicates a deep and long fetch of moisture impacting the
Northwest Pacific Coast this afternoon...ahead of a deep Gulf of
Alaska trough with the outriding showers creeping into the
forecast area this evening. This situation will be aggravated on
Monday as a vigorous upper level short wave now faintly visible as
a digging wave near 150W tears into the region providing copious
dynamic support with jet divergence...cyclonic diffluence and
differential PVA as well as a healthy surface cold front.
Precipitable water values available for exploitation by this lift
will be on the order of an inch or more...almost 200 percent of
normal. The confluence of all these elements will bring a number
of meteorological inconveniences to the region Monday afternoon
and evening.
Rain showers...
For the first time in weeks a very moist air mass will be
exploited by synoptic forcing into a dense area of hefty and
widespread shower activity...mainly focused over the eastern and
northern zones...but with hit-and-miss showers possible just about
anywhere in the region. On average most locations in the western
basin will experience only a few hundredths of an inch...but
amounts may exceed 1/4 to 1/2 inch east of a line from Republic
to Pomeroy and near the Cascade Crest...with some locations being
run over by multiple showers through the afternoon.
Thunderstorms...While the thunder potential will be fairly small
at any given location...the best chance for appreciable surface
based instability on the order of a few hundred Joules/Kg will be
over the southeastern zones during the afternoon and evening
hours. The magnitude of the forcing and wind shear in the lower
atmosphere suggests that any storms that get going south of a line
from about La Crosse to Mullan Pass have the potential to become
organized and strong producers of hail and gusty winds. north of
this line there will likely be too much cloud cover early in the
day to generate significant SB CAPE any any storms will be hit-
and-miss isolated embedded cells in the predominant shower
activity. These storm cores may also produce brief torrential
downpours but will likely also be fast movers for only a remote
threat of flash flooding.
Synoptic wind...The surface cold front will cross the region from
west to east during the afternoon period. Windy and gusty conditions
will develop over the deep basin during the afternoon and over the
eastern basin in the late afternoon and early evening hours as the
precipitation band exits to the east. The gradient magnitude and
gust potential from mixing does not appear to support Wind
Advisory criteria at this time...but solid 15 to 25 mph sustained
winds with gusts possibly as high as 40 mph will be possible into
the evening over exposed locations of the basin during the
evening hours.
Monday night...After the evening activity dies down...windy
condiitons will gradually abate to merely breezy and should keep
overnight lows elevated even with partial clearing.
Tuesday through Wednesday...A general zonal flow regime off the
Pacific will settle over the region during this period. This flow
should keep shower activity to a minimum over the basin...with a
chance of mountain showers (of the snow variety on the higher
peaks) each afternoon and evening north and east of the basin. No
further organized storms or frontal complexes are forecast through
Wednesday. The main story will be cooler and more seasonably
normal temperatures with occasionally breezy conditions. /Fugazzi
Wednesday night to Sunday: A progressive pattern with mean
continued shower chances, especially in the mountains, and near
seasonal temperatures. Models point to at least 2 organized
disturbances entering the West: one around Thursday and Friday and
another toward the weekend. There remains disagreement over
precise timing and track. Regardless embedded smaller-scale
vorticity maxima slip by. With Moisture and instability deepens
later Thursday and especially Friday, with PWATs rising to
120-170% of normal and CAPE values between 100-400 J/kg roughly
across north-central and east WA and north ID. Combined with any
forcing that comes through this will lead to an above average
threat of shower, with a chance of thunderstorms mixed in. Subtle
ridging develops going into Saturday before the next wave rides in
Sunday. This suggests a brief shift in the precipitation threat to
the mountains going into Saturday and early Sunday, before being
chances are renewed by later Sunday. Yet given limited agreement
over precise timing I kept PoPs closer to climatological values
between Saturday and early Sunday. This means while precipitation
chances decline from Friday, they do not end. The main exception
looks to be in the lee of the Cascades and deer Columbia Basin
where the westerly flow and its shadowing effects will hold PoPs
lower. /J. Cote`
&&
.AVIATION...
18Z TAFS: A mid level front will stall over the region today from
KEAT into the mountains of NE WA. Very light rain or sprinkles is
expected ahead of the front, which may impact the KEAT and KMWH
taf sites. Some isolated showers and thunderstorms may begin to
fire off over the higher terrain of the northeast Blue Mountains
over into the Idaho Panhandle after 21Z, but confidence is low as
there is some CIN to overcome without much of a kicker pushing
through. Breezy westerly winds are expected this afternoon as well
with gusts up to 25 to 30 mph possible. /SVH
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 55 67 41 62 43 66 / 10 80 50 0 10 10
Coeur d`Alene 52 68 43 62 41 67 / 20 80 50 10 10 10
Pullman 51 69 40 61 40 65 / 10 80 50 0 10 10
Lewiston 58 79 44 71 45 74 / 20 70 40 0 10 10
Colville 50 67 43 67 39 72 / 30 80 60 10 10 20
Sandpoint 49 65 42 62 39 67 / 30 80 80 20 10 10
Kellogg 53 68 42 59 40 64 / 20 80 70 10 10 10
Moses Lake 55 72 46 70 44 74 / 20 40 10 0 0 0
Wenatchee 55 70 47 69 45 72 / 10 60 10 0 10 10
Omak 49 71 42 69 39 73 / 10 60 20 10 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
919 PM PDT Sat May 11 2013
.SYNOPSIS...
Changes in the weather pattern will arrive on Sunday with the
arrival of a cold front. There will be a chance of showers and
thunderstorms Sunday and again on Monday. The best chances however
will be on Monday...with some thunderstorms possibly strong to severe.
Gusty winds will be possible Sunday and Monday as well. Temperatures
will return closer to average by Monday. Tuesday and Wednesday
should be mainly dry over the Inland Northwest. A return of showers
is expected Thursday or Friday.
&&
.DISCUSSION...
Overall the forecast for tonight looks in good shape with only
very minor upward temperature adjustments for a few locations.
Abundant mid and high level clouds passing through the area will
reduce radiational cooling potential tonight which will allow for
a very mild night. For most locations...lows in the mid 50s to
lower 60s will end up being around 15 degrees above normal.
For Sunday...most model guidance shows only marginal instability
for showers...and especially thunderstorm development as a
weakening front crosses the Cascades in the afternoon. However
ahead of the front the NAM model continues to show an area of
negative 700-500mb theta-e lapse rates with elevated CAPES of
50-100 J/KG mainly east of a line from Moses Lake to Republic in
the morning. This could result in a stray lightning strike...but
more likely just high based shower activity with just sprinkles
reaching the ground. The latest 02z HRRR supports this idea. All
in all...Sunday likely will be dry for most of the day for most
locations in the Inland Northwest with temperatures still well
above normal. However enough instability and mid level moisture
will be present to warrant a chance for showers that could moves
over areas for a brief duration. The front will also bring
breezy to locally windy conditions Sunday afternoon. JW
&&
.AVIATION...
06Z TAFS: Mid and high clouds will continue to move into the Inland
Northwest through 06z Monday. High pressure will begin to shift
east on Sunday with a weak cold front passage. This may provide
enough lift for a better chance for showers and isolated thunderstorms
mainly over Northeast Washington and the North Idaho Panhandle.
However models have backed off a bit on the coverage of showers
and instability such that most...if not all...TAF sites may stay
dry through Sunday evening. The front will kick up some gusty
winds...with southwest winds gusting to 15-25 kts for most TAF
sites. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 60 80 55 69 43 63 / 10 30 20 60 50 10
Coeur d`Alene 57 79 54 69 43 61 / 0 30 40 60 60 10
Pullman 58 79 52 68 40 60 / 10 20 40 70 50 10
Lewiston 62 87 59 76 47 69 / 10 20 40 70 50 0
Colville 55 84 50 72 41 68 / 0 50 20 50 70 20
Sandpoint 53 78 52 69 41 61 / 0 50 40 60 90 20
Kellogg 59 79 52 68 42 57 / 0 40 50 80 70 20
Moses Lake 62 85 56 74 46 73 / 10 20 10 40 20 0
Wenatchee 62 80 56 70 46 69 / 10 20 10 40 20 0
Omak 56 81 51 71 41 70 / 10 10 10 50 40 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1034 PM CDT MON MAY 13 2013
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 233 PM CDT MON MAY 13 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE
CENTERED OVER THE CENTRAL GREAT LAKES AND A WARM FRONT EXTENDING
SOUTH ACROSS THE GREAT PLAINS. LEADING EDGE OF THE WARM/MOIST AIR
ALOFT IS PRODUCING A NARROW BAND OF LIGHT RAIN ALONG THE WI/MN
BORDER THIS AFTERNOON...WHICH IS MEASURING A HUNDREDTH OR TWO
ACCORDING TO THE OBS. BAND OF LIGHT RAIN ALONG THIS 295-300K
MOISTURE ADVECTION WILL PUSH INTO CENTRAL WISCONSIN AROUND
5PM...DESPITE VERY DRY AIR PRESENTLY AT THE SURFACE. WEST OF THE
WARM FRONT...TEMPERATURES ARE MAINLY IN THE 80S AND A COUPLE 90
DEGREE READINGS ARE OUT THERE AS WELL. THE MAIN FORECAST CONCERNS
ARE TIMING OF THE PRECIP LATER THIS AFTERNOON INTO THIS
EVENING...FOLLOWED BY TEMPS AND SMALL THUNDER CHANCES TOMORROW.
TONIGHT...295-300K MOISTURE ADVECTION WILL PUSH A BAND OF LIGHT RAIN
ACROSS THE AREA LATER THIS AFTERNOON AND THROUGH THE EVENING.
MID-LEVEL LAPSE RATES ARE POOR AND SURFACE HUMIDITIES ARE IN THE
20S...SO SHOWERS SHOULD NOT AMOUNT TO MUCH. BUT OBS UPSTREAM
INDICATE A HUNDREDTH OR TWO OF ACCUM...SO WILL SHOW THIS IN THE
FORECAST AND RAISE POPS INTO THE LIKELY RANGE. THIS BAND WILL EXIT
LATE THIS EVENING...BUT A SECONDARY SURGE OF MOISTURE MAY CAUSE
ADDITIONAL REDEVELOPMENT OF SHOWERS OVER THE EASTERN HALF OR THIRD
OF THE FORECAST AREA AFTER MIDNIGHT. THINK PRECIP CHANCES WILL
LIKELY BE OVER BY THE START OF THE MORNING COMMUTE WHILE SKIES WILL
BE CLEARING FROM WEST TO EAST AT THE SAME TIME. PLENTY OF CLOUDS
AND A LIGHT SE WIND WILL KEEP TEMPS CONSIDERABLY WARMER THAN LAST
NIGHT AND WILL GO WITH LOWS IN THE LOW TO MID 40S.
TUESDAY...ELEVATED WARM FRONT WILL BE SHIFTING ACROSS LAKE MICHIGAN
EARLY TUESDAY MORNING...WHICH WILL RESULT IN CLEARING SKIES ACROSS
EASTERN WISCONSIN EARLY ON. EVEN THOUGH WILL LIKELY SEE CIRRUS
OVERHEAD...MODELS FORECAST VERY DRY AIR ARRIVING IN THE LOW TO MID
LEVELS SO DO NOT SEE A THREAT OF PRECIP THROUGH MID-AFTERNOON. BY
MID TO LATE AFTERNOON...LOW PRESSURE WILL BE ACROSS CENTRAL
MINNESOTA...AND A 850MB LLJ WILL PUSH A WARM FRONT INTO SW
WISCONSIN. ORDINARILY...MASS CONVERGENCE ON THE NOSE OF THE LLJ
WOULD BE CONDUCIVE FOR THUNDERSTORMS...ESPECIALLY WITH MID-LEVEL
LAPSE RATES AROUND 8 C/KM....BUT THE INCOMING AIRMASS IS SO DRY
BELOW 600MB...AND EXPECT SURFACE DEWPOINTS TO FALL THROUGH THE
AFTERNOON. THIS RESULTS IN PROGGED CONVECTIVE INHIBITION OF 200-300
J/KG LATE IN THE AFTERNOON WHEN THE FORCING ARRIVES...WHICH LOOKS
AWFULLY TOUGH TO OVERCOME. WILL LEAVE AN ISOLATED MENTION IN THE
FORECAST OVER CENTRAL AND NORTH-CENTRAL WISCONSIN. STRONG WARM
ADVECTION WILL PUSH TEMPS INTO THE LOWER 80S OVER CENTRAL
WISCONSIN...BUT A NE WIND WILL KEEP TEMPS IN THE 50S AND 60S OVER
FAR NE WISCONSIN.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 233 PM CDT MON MAY 13 2013
MAIN FCST CONCERNS INCLUDE SVR TSTM POTENTIAL TUESDAY EVENING...
A DRY PERIOD FOR THE MIDDLE TO LATE PART OF THE WORK WEEK...THEN
A RETURN TO SHOWERY BUT SEASONABLE PERIOD FOR THE WEEKEND AND
EARLY NEXT WEEK.
NOTHING HAS CHANGED FOR TUESDAY NIGHT...WITH ENOUGH ELEVATED INSTABILITY
(MUCAPES 750-1500 J/KG) AND SHEAR (STG DEEP LAYER SHEAR AND 0-3 KM
HELICITIES OF 500-700) TO SUPPORT ELEVATED SUPERCELL TSTMS...BUT A
DRY AND CAPPED ATMOSPHERE LIKELY SUPPRESSING CONVECTIVE INITIATION.
HAD TO LIFT PARCELS FROM THE 850-750 MB LAYER TO GET CONVECTIVE
INHIBITION UNDER 50 J/KG...AND LOWER LEVEL PARCELS ARE MUCH MORE
STRONGLY CAPPED. BEST BEST FOR CONVECTIVE INITIATION WILL LIKELY BE
ON THE NOSE OF A 40 KT LLJ AS IT MOVES INTO NE WI DURING THE EVENING.
HAVE LOWERED POPS SLIGHTLY FROM THE PREVIOUS FEW FCSTS...BUT CAN`T
RISK A DRY FCST...GIVEN THE SVR WX PARAMETERS THAT ARE IN PLACE. SPC
HAS OUR AREA IN THE DAY 2 SEE TEXT...WHICH SEEMS REASONABLE. ANY
THREAT OF CONVECTION SHOULD END BY 06Z/WED AS THE H8 MOISTURE
CONVERGENCE SHIFTS EAST...AND THE COLD/OCCLUDED FRONT REACHES LAKE
MICHIGAN.
LOOKS LIKE A DRY PERIOD FROM LATE TUESDAY NIGHT THROUGH THURSDAY
NIGHT OR FRIDAY MORNING...AS THE COLD FRONT SAGS WELL SOUTH OF THE
REGION AND WEAK HIGH PRESSURE ARRIVES. DEEP MIXING ON WEDNESDAY AND
THURSDAY SHOULD ALLOW TEMPERATURES TO WARM INTO THE LOWER TO MIDDLE
70S IN MOST PLACES...AND ALSO CAUSE DEW POINTS/RELATIVE HUMIDITIES
TO CRASH DURING THE AFTERNOONS. GIVEN THE DRYNESS OF THE AIR MASS...
HAVE LOWERED MIN TEMPS CONSIDERABLY ON WEDNESDAY NIGHT...ESPECIALLY
IN THE TYPICAL COLD SPOTS IN NC WI.
THE PATTERN WILL UNDERGO A SIGNIFICANT CHANGE FOR THE WEEKEND AND
EARLY NEXT WEEK. AN UPPER LEVEL TROF IS EXPECTED TO DEVELOP OVER
THE ROCKIES ON FRIDAY...THEN TRACK EAST TO THE WESTERN GREAT LAKES
BY SUNDAY/MONDAY. AS THIS OCCURS...LOW PRESSURE WILL DEVELOP OVER
THE HIGH PLAINS...THEN LIFT EAST-NORTHEAST TOWARD THE REGION. THIS
WILL CAUSE THE OLD COLD FRONT TO LIFT BACK TO THE NORTH AS A WARM
FRONT...THEN BECOME STATIONARY ACROSS WI LATE IN THE PERIOD. THIS
WILL SET THE STAGE FOR AN EXTENDED PERIOD OF SHOWERS AND SCT TSTMS...
WITH THE POTENTIAL FOR SIGNIFICANT RAINFALL AMOUNTS. TEMPERATURES
SHOULD REMAIN NEAR SEASONAL NORMALS...WITH HIGHS IN THE 60S TO
AROUND 70.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1034 PM CDT MON MAY 13 2013
MID LEVEL CLOUDS WITH ISOLATED SHOWERS WILL LINGER
EASTERN WISCONSIN OVERNIGHT. LLWS CONDITIONS TO PERSIST THROUGH
15Z TUESDAY. VFR CONDITIONS WILL CONTINUE TUESDAY...WITH PERHAPS A
CHANCE OF A MVFR CIGS WITH SHOWERS OR A THUNDERSTORM TUESDAY NIGHT
WITH THE PASSAGE OF A COLD FRONT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......TDH
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 232 PM CDT SUN MAY 12 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE HIGH
PRESSURE STRETCHING FROM SOUTH-CENTRAL CANADA TO THE WESTERN GULF
COAST EARLY THIS AFTERNOON WHILE LOW PRESSURE PEELS AWAY OVER
QUEBEC. AS CYCLONIC FLOW ABATES AND DRIER AIR BUILDS IN FROM THE
WEST...WIDESPREAD MORNING STRATO-CU HAS BEEN RETREATING TO THE
NORTHEAST...TURNING SKIES MOSTLY CLEAR TO PARTLY CLOUDY OVER MUCH OF
CENTRAL AND NORTHEAST WISCONSIN. PLENTY OF CLEAR SKIES BENEATH THE
SURFACE HIGH OFF TO THE WEST...WHICH WILL MOVE INTO THE AREA
TONIGHT. EVEN FARTHER WEST...A WARM FRONT OVER THE LEE OF THE
ROCKIES WILL ENTER THE REGION TOMORROW AFTERNOON. FIRST CONCERN
IS TEMPS TONIGHT...FOLLOWED BY SMALL PRECIP CHANCES TOMORROW
AFTERNOON.
TONIGHT...HIGH PRESSURE OVER THE GREAT PLAINS WILL SHIFT ACROSS THE
WESTERN HALF OF WISCONSIN TONIGHT. AS CLOUDS CONTINUE TO MIX OUT
THIS AFTERNOON...SKIES WILL BECOME CLEAR AND WINDS WILL BECOME LIGHT
AND VARIABLE BY EARLY TO MID-EVENING. GOOD RADIATIONAL CONDITIONS
WILL THEN EXIST FOR THE REST OF THE NIGHT. LOW TEMPS UPSTREAM OVER
WESTERN WISCONSIN AND MINNESOTA WERE MOSTLY AT OR BELOW 32 DEGREES
AND EXPECT SIMILAR READINGS LATE TONIGHT. TEMPS WERE ALSO IN THE 34
TO 36 DEGREE RANGE OVER THE FOX VALLEY AND LAKESHORE LAST
NIGHT...WHEN THERE WAS CONSIDERABLY MORE WIND AND CLOUDS. WILL NOT
HAVE THIS LUXURY TONIGHT...SO FIGURE TEMPS WILL FALL BELOW FREEZING
ACROSS MOST OF THE CWA. WILL EXPAND THE FREEZE WARNING.
MONDAY...HIGH PRESSURE WILL SLIDE TO THE EAST ACROSS THE CENTRAL
GREAT LAKES. WARM ADVECTION WILL RAMP UP ON THE BACKSIDE OF THE
HIGH AT THE SAME TIME AS MID AND HIGH CLOUDS SPILL OVER THE
MID-LEVEL RIDGE AXIS. AS A RESULT...WILL SEE A SLOW INCREASE OF
CLOUDS OVER THE COURSE OF THE DAY. AFTER 21Z...ENOUGH MOISTURE
ADVECTION LOOKS TO TAKE PLACE TO NEARLY SATURATE THE COLUMN OVER
CENTRAL AND NORTH-CENTRAL WISCONSIN. MID-LEVEL LAPSE RATES ARE VERY
POOR...BUT MID-LEVEL FGEN APPEARS SUFFICIENT FOR THE POSSIBILITY OF
SCATTERED LIGHT SHOWERS DEVELOPING. WILL INCREASE POPS INTO THE
40-50 PERCENT RANGE. THERE IS A FAIRLY LARGE RANGE IN GUIDANCE FOR
TEMPS TOMORROW AFTERNOON...BETWEEN THE COLD ECMWF AND WARM NAM.
SPLITTING THE DIFFERENCE SHOULD GET TEMPS CLOSE AND WILL GO WITH
HIGHS IN THE UPPER 50S TO LOW 60S BUT COOLER LAKE SIDE.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 232 PM CDT SUN MAY 12 2013
PCPN TRENDS MONDAY NIGHT INTO TUESDAY NIGHT...THE POTENTIAL FOR
SVR TSTMS TUESDAY NIGHT...GUSTY WINDS ON WEDNESDAY...PCPN TRENDS
NEXT WEEKEND...AND TEMPERATURES THROUGHOUT THE PERIOD ARE THE
MAIN FCST CONCERNS.
STRONG H8 WAA/MOISTURE CONVERGENCE WILL BRING A BAND OF SHOWERS THROUGH
THE AREA ON MONDAY NIGHT. ALTHOUGH THE RAIN WILL NOT LAST LONG AND QPF
AMOUNTS ARE EXPECTED TO BE LIGHT...FELT THAT POPS NEEDED TO BE RAISED
A LITTLE BIT. WAA/ISENT LIFT WILL CONTINUE ON TUESDAY AS A WARM FRONT
LIFTS INTO WISCONSIN. THIS FRONT IS EXPECTED TO MOVE INTO CENTRAL WI
LATE IN THE AFTERNOON. DESPITE SOME PERSISTENT FORCING...AN
INCREASINGLY CAPPED ATMOSPHERE AND LATE ARRIVAL OF THE INSTABILITY
AXIS PRECLUDES ADDING ANYTHING MORE THAN SLGT CHC/CHC POPS...MAINLY
OVER NORTHERN WI. TEMPERATURES WILL VARY GREATLY...WITH READINGS IN
THE MID 50S TO LOWER 60S NEAR THE LAKE...AND INLAND TEMPS RANGING
FROM THE UPPER 60S FAR NE WI TO THE LOWER TO MIDDLE 80S IN C WI.
THE WARM FRONT WILL LIFT NORTH TUESDAY...QUICKLY FOLLOWED BY THE COLD
FRONTAL PASSAGE DURING THE LATE EVENING AND OVERNIGHT HOURS. ELEVATED
CAPE OF 1500-2000 J/KG...VERY STEEP LAPSE RATES OF 7-8 C/KM...DEEP
LAYER SHEAR OF 40-50+ KTS AND 0-3 KM HELICITIES OF 400-500 WILL
PROVIDE PLENTY OF SUPPORT FOR SEVERE TSTMS...BUT CAPPING MAY BE
PROHIBITIVE FOR CONVECTIVE INITIATION. BEST CASE SCENARIO FROM THE
NAM AND A FEW OF THE SREF ENSEMBLE MEMBERS SHOW CINH OF 40-70
J/KG FOR A PARCEL LIFTED FROM THE 850-800 MB LEVEL OVER FAR
NORTHERN WI...BUT OTHER FCST SOUNDINGS SHOWED MUCH HIGHER CINH...
EVEN FROM ELEVATED PARCELS. WILL CONTINUE WITH CHC POPS TUESDAY
EVENING...AND A MENTION OF THE SVR TSTM POTENTIAL IN THE HAZARDOUS
WEATHER OUTLOOK...BUT HAVE TO ACKNOWLEDGE THE POTENTIAL FOR A MAINLY
DRY FCST. ANY PCPN THAT DOES DEVELOP WILL COME TO AN END OVERNIGHT
AS THE COLD FRONT SHIFTS EAST.
CAA...AN INCREASING NW PRESSURE GRADIENT AND DEEP MIXING WILL LEAD
TO A BREEZY/WINDY DAY ON WEDNESDAY. MIXING THROUGH 825-775 MB SUPPORTS
HIGH TEMPS IN THE LOWER TO MIDDLE 70S IN MOST LOCATIONS.
THE COLD FRONT WILL SETTLE SOUTH OF WISCONSIN FROM WEDNESDAY THROUGH
FRIDAY...AS ANOTHER COLD FRONT SAGS SOUTH OUT OF CANADA. WITH THE
REGION IN BETWEEN SYSTEMS...EXPECT A GENERALLY DRY PERIOD OVER THE
LATTER HALF OF THE WORK WEEK...WITH TEMPERATURES AT OR A LITTLE
ABOVE NORMAL.
LOW PRESSURE IS EXPECTED TO APPROACH FROM THE CENTRAL PLAINS THIS
WEEKEND...AND REACH THE IOWA VCNTY BY SUNDAY. AS THIS HAPPENS...
THE FRONT THAT STALLED TO OUR SOUTH WILL LIFT BACK INTO SOUTHERN
WISCONSIN...ALONG WITH ITS ASSOCIATED MOISTURE/ELEVATED INSTABILITY.
THIS SHOULD LEAD TO SHOWERS AND SCT TSTMS OVER THE REGION...ALONG
WITH COOLER TEMPERATURES DUE TO EAST WINDS AND ABUNDANT CLOUD COVER.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1230 PM CDT SUN MAY 12 2013
SCATTERED TO BROKEN CLOUDS BETWEEN 3500 FT AND 5000 FT WILL
GRADUALLY DISSIPATE DURING THE AFTERNOON. THIS WILL SET UP A CLEAR
AND COLD NIGHT. FROST WILL LIKELY FORM ON AIRCRAFT LATE TONIGHT.
MONDAY WILL START OUT SUNNY THOUGH MIDDLE AND HIGH CLOUDS WILL BE
ON THE INCREASE THROUGH THE DAY. A FEW SHOWERS ARE POSSIBLE OVER
CENTRAL AND NORTH-CENTRAL WISCONSIN LATE IN THE AFTERNOON.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ020-022-030-
031-035>040-045-048>050-073-074.
&&
$$
SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1146 AM CDT SUN MAY 12 2013
.UPDATE...
ISSUED AT 1146 AM CDT SUN MAY 12 2013
WILL EXPAND FROST ADVISORY WEST TO INCLUDE WABASHA...WINONA...
HOUSTON...ALLAMAKEE AND CLAYTON COUNTIES ON WEST SIDE OF THE MS
RIVER. TERRAIN IN THESE COUNTIES INCLUDES A LOT OF SHELTERED
VALLEYS DUE TO THE STEEP TERRAIN AND TRIBUTARY RIVERS/STREAMS
FLOWING TOWARD THE MS RIVER. WINDS IN THESE VALLEYS LIKELY TO STAY
DECOUPLED THRU THE NIGHT...WITH STRONG RADIATIONAL COOLING AND COLD
AIR DRAINAGE. PATCHY TO AREAS OF FROST EXPECTED IN THESE COUNTIES
WITH LOWS IN THE LOWER 30S...NOT THAT DIFFERENT FROM NEIGHBORING
AREAS/COUNTIES ON THE EAST SIDE OF THE MS RIVER.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT SUN MAY 12 2013
MAIN FORECAST CONCERN IS ON FROST/FREEZE CONDITIONS TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE WESTERN U.S. INTO ALBERTA WHILE ANOMALOUSLY
DEEP TROUGHING WAS PRESENT FROM HUDSON BAY INTO THE WESTERN GREAT
LAKES REGION. THE FORECAST AREA LIES ON THE BACK SIDE OF THE
TROUGHING...BUT STILL EAST OF THE INFLECTION POINT...WHICH RESULTS
IN NORTHWEST FLOW FROM THE SURFACE TO 500MB. THE FLOW CONTINUED TO
DRAG COLDER AIR SOUTHEAST WITH RAP 850MB TEMPS RANGING FROM -3C OVER
NORTHEAST IOWA TO -9C IN TAYLOR COUNTY WISCONSIN. DESPITE THE COLD
850MB TEMPS...READINGS ARE GENERALLY IN THE MID 30S TO AROUND 40...
STAYING UP BECAUSE OF THAT NORTHWEST WIND OF 5-10 KT AT THE SURFACE
KEEPING THE BOUNDARY LAYER MIXED. A LOT OF DRY AIR CONTINUES TO FLOW
IN TOO ON THE NORTHWEST WINDS FROM HIGH PRESSURE IN THE PLAINS.
DEWPOINTS ARE IN THE TEENS ACROSS MUCH OF THE DAKOTAS INTO MN AND
20S OVER WISCONSIN. COMBINATION OF THE WIND...TEMPERATURES AND DRY
AIR PRECLUDING ANY FROST DEVELOPMENT THUS FAR. THE AFOREMENTIONED
DRY AIR IS ALSO QUITE DEEP...REFLECTIVE FROM 00Z SOUNDINGS AT BIS...
ABR AND MPX HAVING PRECIPITABLE WATER VALUES OF 0.1-0.2 INCHES...OR
20-40 PERCENT OF NORMAL. THIS DRY AIR HAS HELPED CLEAR SKIES OUT
WEST OF WISCONSIN. SCT-BKN CLOUDS HAVE BEEN FLOWING ACROSS WISCONSIN
IN THE CYCLONIC FLOW IN THE UPPER TROUGH. FARTHER TO THE WEST UNDER
THE UPPER RIDGE...00Z SOUNDINGS FROM SAN FRANSISCO TO SALT LAKE CITY
AND NORTH TO GREAT FALLS MT ALL REPORTED 850MB TEMPS OF 20C OR
GREATER. THESE ARE 1.5-2.5 STANDARD DEVIATIONS ABOVE NORMAL.
BOTH THE UPPER RIDGE AND ANOMALOUSLY DEEP TROUGH ARE PROGGED TO
PROGRESS EASTWARD DURING THE NEXT 24 HOURS...PUSHED ALONG BY A
FAIRLY POTENT SHORTWAVE TROUGH APPROACHING THE PACIFIC NORTHWEST
COAST AT 12Z MONDAY. IT APPEARS THIS EVENING IS WHEN THE INFLECTION
POINT BETWEEN THE UPPER RIDGE AND DEEP TROUGH WILL REACH THE
FORECAST AREA. THIS MEANS TO PLAN ON THE SURFACE HIGH OVERHEAD AT
ABOUT THE SAME TIME.
TODAY...THE COMBINATION OF DRY AIR AND BEING FARTHER AWAY FROM THE
COLD POOL OF THE UPPER TROUGH WILL RESULT IN SUNNY SKIES. SINCE THE
AREA STAYS IN A GRADIENT AHEAD OF THE SURFACE HIGH AND WE HAVE FULL
SUN FOR DEEP MIXING...ANOTHER BREEZY DAY IS LIKELY...BUT NOT NEARLY
AS WINDY AS YESTERDAY. TEMPERATURES ARE DEFINITELY GOING TO STAY ON
THE COOL SIDE...THOUGH...WITH 850MB TEMPS HOLDING STEADY THROUGH
18Z. HIGHS SHOULD END UP VERY SIMILAR TO YESTERDAY.
TONIGHT...A REALLY GOOD RADIATIONAL COOLING SETUP IS FORECAST. WITH
THE SURFACE HIGH MOVING OVER THE AREA DURING THE EVENING...WINDS
WILL DECOUPLE EVERYWHERE. ADDITIONALLY...WE HAVE ALL OF THE DRY AIR
ACCOMPANYING THE SURFACE HIGH. THUS...TEMPERATURES SHOULD PLUMMET
DURING THE EVENING HOURS AFTER SUNSET. NOW...AFTER MIDNIGHT...THE
SURFACE RIDGE BEGINS TO PUSH EAST INTO CENTRAL WISCONSIN. THIS MEANS
A SOUTHERLY WARM ADVECTION FLOW WILL COMMENCE OVER WESTERN PORTIONS
OF THE FORECAST AREA. THEREFORE...OUR WISCONSIN COUNTIES CONTINUE TO
LOOK THE MOST FAVORABLE FOR THE COLDEST CONDITIONS...AND THE COLDEST
OVERALL OVER CENTRAL WISCONSIN. STAYED TOWARDS THE COLD SIDE OF
GUIDANCE FOR LOWS. GIVEN THE CONSISTENCY FOR TONIGHT TO BE COLD...
HAVE ISSUED FREEZE WARNINGS FOR THE PREVIOUS FREEZE WATCH AREA AND A
FEW EXTRA COUNTIES WHERE TEMPS ARE NOW FORECAST COLDER...WITH FROST
ADVISORIES FOR THE REST OF OUR WISCONSIN COUNTIES.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 320 AM CDT SUN MAY 12 2013
MONDAY THROUGH TUESDAY NIGHT...THE UPPER RIDGING OVER THE WESTERN
U.S. IS PROGGED TO CONTINUE TO GET PUSHED EASTWARD WHILE FLATTENING
WITH TIME. THIS IN RESPONSE TO THE POTENT SHORTWAVE OFF THE PACIFIC
NORTHWEST AT 12Z MONDAY TRACKING EASTWARD ALONG THE U.S./CANADIAN
BORDER. OVERALL MODELS ARE IN PRETTY GOOD AGREEMENT ON THE TRACK AND
SPEED OF THIS SHORTWAVE...WITH THE EXCEPTION OF THE 12.00Z NAM
WHICH BECOMES SLIGHTLY FASTER COME TUESDAY AND TUESDAY NIGHT. HAVE
DISCOUNTED THE NAM PROGRESSION AS AN OUTLIER FOR NOW. THE
PROGRESSIVE NATURE OF THE RIDGE AND SHORTWAVE RESULTS IN A VARIETY
OF ISSUES TO CONTEND WITH...
1. PRECIPITATION CHANCES AND TEMPERATURES MONDAY INTO MONDAY NIGHT.
A WARM FRONT AHEAD OF THE UPPER RIDGE AXIS IS FORECAST TO CROSS THE
AREA MONDAY NIGHT. PACIFIC MOISTURE MOVING THROUGH THE UPPER RIDGE
IN CONJUNCTION WITH ISENTROPIC LIFT AHEAD OF THIS WARM FRONT WILL
LIKELY TO LEAD TO EXTENSIVE MID AND HIGH CLOUDS. ADDITIONALLY...THE
LIFT APPEARS STRONG ENOUGH TO GENERATE PRECIPITATION FROM THESE
CLOUDS. THE BIG PROBLEM...THOUGH...IS LOW LEVEL DRY AIR LEFT OVER
FROM THE CURRENT CANADIAN HIGH PRESSURE AREA. OVERALL...12.00Z MODEL
GUIDANCE HAS BACKED OFF ON THE AMOUNT OF QPF POSSIBLE FROM THESE
CLOUDS...ESPECIALLY THE GFS...SUGGESTING THE DRY AIR MAY BE ABLE TO
ABSORB MUCH OF THE PRECIPITATION. HOWEVER...ALL GUIDANCE DOES
SUGGEST SOME LIGHT QPF POSSIBLE...THUS THE 20-40 PERCENT CHANCES
FROM THE PREVIOUS FORECAST STILL SEEMS REASONABLE. TIMING BETWEEN
18Z MONDAY TO 06Z TUESDAY ALSO STILL LOOKS GOOD. SHOULD SEE THE
CLOUDS AND PRECIPITATION PROGRESS EASTWARD THROUGH TIME DUE TO THE
PROGRESSION OF THE UPPER RIDGE. THE CLOUDS COMBINED WITH 850MB TEMPS
AT 18Z MONDAY OF 1C EAST TO 6C WEST ARE LIKELY TO KEEP TEMPERATURES
BELOW NORMAL...BUT NOT AS COLD AS TODAY.
2. HOW WARM TEMPERATURES WILL GET ON TUESDAY. THE SIGNAL OF A
CHINOOK WARM FRONT OFF THE ROCKIES...ACCOMPANYING THAT POTENT
SHORTWAVE...REMAINS FORECAST TO PUSH EAST THROUGH MUCH OF THE
FORECAST AREA DURING THE DAY TUESDAY. INCREDIBLY WARM 850MB TEMPS
FOR MID MAY ARE PROGGED TO FOLLOW IN ITS WAKE...WITH READINGS BY 00Z
OF 18-20C OVER CENTRAL WISCONSIN TO 22-24C WEST OF THE MISSISSIPPI
RIVER...OR 2 TO 3 STANDARD DEVIATIONS ABOVE NORMAL. SEEING THE
OBSERVED 850MB TEMPS UNDER THE UPPER RIDGE RIGHT NOW OVER THE
WESTERN U.S...THESE SEEM REASONABLE. THE QUESTION IS WITH A WARM
ADVECTION PATTERN THROUGH THE DAY...CAN WE MIX TO THESE 850MB TEMPS.
MODELS CONTINUE TO BE NOTORIOUSLY HIGH WITH SURFACE DEWPOINTS IN
THIS SITUATION...PREVENTING MODELS FROM MIXING ENOUGH. FOR
EXAMPLE...THE 12.00Z GFS/ECMWF/CANADIAN JUMP THEM OVER IOWA FROM
50-55 AT 12Z TO 60-65 AT 18Z...ALL LIKELY DUE TO EVAPOTRANSPIRATION
THAT IS NOT THERE YET. ADDITIONALLY...A DOWN-SLOPE FLOW FROM THE
ROCKIES USUALLY ENDS UP WITH DRIER DEWPOINTS...ESPECIALLY THIS TIME
OF YEAR. THUS...HAVE CONTINUED TO STAY TOWARDS THE WARM SIDE OF
GUIDANCE. ALTHOUGH THE 12.00Z NAM IS SLIGHTLY TOO PROGRESSIVE...ITS
TEMPERATURES SEEM REASONABLE. FOLLOWED MOS GUIDANCE MORE FOR
DEWPOINTS SINCE MOS HAS BEEN DOING MUCH BETTER IN THIS DEPARTMENT.
3. COLD FRONT CROSSING TUESDAY NIGHT AND POTENTIAL FOR PRECIPITATION
WITH IT. 12.00Z NAM AND GFS ARE JUST SLIGHTLY FARTHER SOUTH WITH THE
TRACK OF THE SHORTWAVE TRACKING ALONG THE CANADIAN BORDER...COMPARED
TO THE 12.00Z ECMWF/UKMET/CANADIAN. THIS DIFFERENCE RESULTS IN THE
NAM/GFS ADDING EXTRA FORCING TO THE LOW LEVEL FRONTOGENESIS ZONE ON
AND BEHIND THE COLD FRONT...AND THUS THE MODELS PRODUCE A BAND OF
PRECIPITATION OVER THE AREA. THE ECMWF/UKMET/CANADIAN ARE DRY. FEEL
THE LATTER MODEL GROUP IS MORE LIKELY TO OCCUR...BUT CONTINUED TO
HONOR THE NAM/GFS SCENARIO WITH A 20 PERCENT CHANCE JUST IN CASE.
WEDNESDAY INTO NEXT WEEKEND...
GOOD MODEL AGREEMENT EXISTS OF THE FLOW STARTING OFF AS ZONAL TO
BEGIN THIS PERIOD. ANY LOW LEVEL FRONTOGENETICAL FORCING BEHIND
TUESDAY NIGHTS COLD FRONT IS SOUTH OF THE AREA FOR WEDNESDAY...SO
WENT DRY DURING THIS TIME. THE ZONAL FLOW DOES NOT LAST LONG...WITH
A NEW TROUGH PROGGED TO COME INTO THE PACIFIC NORTHWEST THURSDAY
NIGHT. THIS CAUSES THE FLOW DOWNSTREAM TO BUCKLE...WITH THE 12.00Z
ECMWF/GFS/CANADIAN ALL SHOWING A SHORTWAVE TROUGH TRACKING ACROSS MN
AND WI THURSDAY INTO THURSDAY NIGHT. HAVE HONORED THE SHORTWAVE WITH
SOME SMALL CHANCES OF PRECIPITATION. WE COULD END UP WITH A DRY DAY
FRIDAY WITH SUBSIDENCE AND HIGH PRESSURE BUILDING IN. LOWERED
PRECIPITATION CHANCES FURTHER AND MAY BE ABLE TO COMPLETELY PULL
THEM WITH THE NEXT EXTENDED FORECAST UPDATE. THINGS LOOK TO PERHAPS
TO GET MORE ACTIVE FOR FRIDAY NIGHT INTO THE WEEKEND AS THE PACIFIC
NORTHWEST TROUGH BEGINS TO APPROACH THE PLAINS. SURPRISINGLY GOOD
MODEL AGREEMENT BETWEEN THE ECMWF AND GFS...ALONG WITH PREVIOUS
RUNS...OF A DEEPENING LOW DOWNSTREAM OVER NEBRASKA. AS ONE WOULD
EXPECT...A SURGE OF MOISTURE TRANSPORT OUT OF THE GULF OF MEXICO IS
AIMED DIRECTLY TOWARDS THE FORECAST AREA AHEAD OF THE LOW.
THUS...PRECIPITATION CHANCES INCREASE...ESPECIALLY ON SATURDAY WHERE
THE CONSENSUS EVEN RESULTS IN 50-60 PROBABILITIES. TEMPERATURES
SHOULD SLOWLY COOL THROUGH THE EXTENDED...BUT STILL STAY AT OR ABOVE
NORMAL WITH A FLOW GENERALLY OFF THE PACIFIC.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1146 AM CDT SUN MAY 12 2013
GENERALLY QUIET VFR CONDITIONS ACROSS THE TAF SITES THIS AFTERNOON
THROUGH MONDAY MORNING AS COOL CANADIAN HIGH PRESSURE DRIFTS EAST
ACROSS THE UPPER MIDWEST. CLOUDS THIS PERIOD LOOK LIMITED TO A FEW
HIGH-BASED DIURNAL CUMULUS THIS AFTERNOON THEN SCT CIRRUS LATE
TONIGHT/MON MORNING. DIURNAL WARMING/MIXING TO PRODUCE NORTHWEST
WINDS 10-15KTS G20KTS THIS AFTERNOON...BECOMING LGT/VARIABLE AS THE
SFC RIDGE AXIS DRIFTS OVERHEAD TONIGHT...THEN SOUTH TO SOUTHWEST 8-
14KT ON THE BACK SIDE OF THE HIGH ON MONDAY. MON AFTERNOON WILL SEE
AN INCREASE OF MID LEVEL MOISTURE/CLOUDS AND A SMALL SHRA CHANCE AT
THE TAF SITES.
&&
.FIRE WEATHER...TUESDAY
ISSUED AT 320 AM CDT SUN MAY 12 2013
AFTER HAVING BREEZY...DRYING AND UNSEASONABLY COOL WEATHER THIS
WEEKEND...INCLUDING FROST/FREEZE CONDITIONS TONIGHT ACROSS
WISCONSIN...CONCERN CONTINUES TO INCREASE ABOUT CRITICAL FIRE
WEATHER CONDITIONS ON TUESDAY. MOST LOCATIONS SHOULD SEE HIGHS
CLIMB INTO THE 80S...WITH SOME WEST OF THE MISSISSIPPI RIVER
REACHING 90. DEWPOINT FORECASTS REMAIN TRICKY...BUT MINIMUM
RELATIVE HUMIDITY VALUES SHOULD HAVE NO PROBLEM FALLING INTO THE
30 TO 40 PERCENT RANGE. IT IS POSSIBLE LOCATIONS SAY ALONG AND
WEST OF US-52 COULD END UP DROPPING TOWARDS 25 PERCENT. COMBINED
WITH SOUTHWEST WINDS OF 15 TO 20 MPH AND HIGHER GUSTS...THE
SITUATION BEARS WATCHING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FROST ADVISORY FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ032-041-
054- 061.
FREEZE WARNING FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ017-029-
033-034-042>044-053-055.
MN...FROST ADVISORY FROM 1 AM TO 7 AM CDT MONDAY FOR MNZ079-088-
096.
IA...FROST ADVISORY FROM 1 AM TO 7 AM CDT MONDAY FOR IAZ011-030.
&&
$$
UPDATE.........RRS
SHORT TERM.....AJ
LONG TERM......AJ
AVIATION.......RRS
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1100 AM CDT SUN MAY 12 2013
.UPDATE...NO CHANGE TO FROST/FREEZE HEADLINES FOR TONIGHT.
PC
&&
.AVIATION/18Z TAFS/...VERY COLD AND BROAD UPPER TROUGH CONTINUES
ACROSS THE UPPER MIDWEST. -34C 500 MILLIBAR TEMP AT KGRB FROM 12Z
RESULTING IN VFR VFR CU FIELD AFFECTING ERN HALF OF WI. SKIES
WILL BE CLEAR TONIGHT. WINDS DIMINISH AS WELL WITH SURFACE RIDGE
AXIS SLIDING ACROSS. MID DECK WILL INCREASE MONDAY AFTERNOON WITH
700 MILLIBAR WARM ADVECTION. BEST POTENTIAL FOR SHRA WILL BE IN SC
WI LATER IN THE AFTERNOON.
PC
&&
.PREV DISCUSSION... /ISSUED 345 AM CDT SUN MAY 12 2013/
TODAY...FORECAST CONFIDENCE...MEDIUM TO HIGH
NOT AS MUCH INSTABILITY OR DYNAMIC PUNCH AS THERE WAS
YESTERDAY...BUT STILL HAVE THE THE WESTERN EDGE OF THE COLD POOL
OVER US...ESPECIALLY OVER THE EASTERN CWA THIS MORNING. SHOULD SEE
CU POP BY MID MORNING. RAP SOUNDINGS SHOW A DEEPER CLOUD LAYER
THAN NAM OR GFS...WITH SOME MINIMAL CAPE DEVELOPING SOME SPRINKLES
IN THE SOUTHEAST IN THE AFTERNOON. WILL LEAVE OUT FOR NOW...BUT
WILL NEED TO BE WATCHED WITH SHEARED VORT DROPPING THROUGH REGION
THIS AFTERNOON PROVIDING A BIT OF EXTRA LIFT. THE COLD AIR
ADVECTION HAS BROUGHT 925 MB TEMPERATURES DOWN TO -1C TO -4C...BUT
MODELS AGREE THAT THEY WILL RECOVER TO +3 TO +5C BY 00Z. THOUGH
WARMEST 925 MB TEMPS WILL ARRIVE TOWARD THE END OF THE
DAY...ENOUGH OF AN INFLUENCE TO LEAN TOWARD WARMER GUIDANCE WITH
MID 50S IN THE WEST...TO AROUND 50 IN THE FAR EAST.
TONIGHT...FORECAST CONFIDENCE...HIGH
GIVEN THE EXPECTED GOOD RADIATIONAL COOLING CONDITIONS AS SURFACE
RIDGE AXIS MOVES OVER THE STATE TONIGHT ...AND WITH BUFKIT SOUNDINGS
SUPPORTING THE THE NAM/GFS 2-METER TEMPERATURES AND MOS GUIDANCE...
WILL ISSUE A FREEZE WARNING FOR THE FAR NW COUNTIES WHERE LOWS TO
BOTTOM OUT IN THE UPPER 20S...AND A FROST ADVISORY FOR THE REST OF
THE CWA WITH LOW 30S AWAY FROM THE IMMEDIATE LAKESHORE. EVEN
MILWAUKEE AND OZAUKEE COUNTIES SHOULD SEE AREAS OF FROST IN THEIR
FAR WEST. THE LOWEST TEMPERATURES ARE CURRENTLY LIMITED TO NORTHERN
SECTIONS OF THE FREEZE WARNING COUNTIES...BUT WARNING WOULD HAVE TO
BE EXPANDED IF THE COLDER NAM IS CORRECT.
MONDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE...MEDIUM
THE AXIS OF SURFACE HIGH PRESSURE WILL BE OVERHEAD MONDAY
MORNING...SO THERE SHOULD BE PLENTY OF SUNSHINE TO START THE DAY.
THE HIGH WILL SLIDE EAST DURING THE DAY...WITH STRONG WARM ADVECTION
ALOFT SLIDING INTO THE WEST BY LATE AFTERNOON. THIS WILL BRING
INCREASING CLOUDS ALONG WITH A CHANCE FOR SHOWERS TO MAINLY WESTERN
PORTIONS OF THE FORECAST AREA.
THE MAX OF THE WARM ADVECTION WILL SLIDE THROUGH MAINLY DURING THE
EVENING HOURS...SO KEPT HIGHEST POPS DURING THAT PERIOD. SHOULD BE
MAINLY DRY THEN TUESDAY AS A WARMER AND CAPPED AIRMASS MOVES INTO
THE FORECAST AREA.
THE SURFACE COLD FRONT IS EXPECTED TO DROP THROUGH SOUTHERN
WISCONSIN TUESDAY EVENING AND OVERNIGHT. MODELS ARE NOT SHOWING MUCH
LIFT WITH THIS FRONT...SO KEPT POPS ON THE LOW END.
TEMPERATURES MONDAY WILL CLIMB BACK TOWARD NORMAL VALUES UNDER
SOUTHERLY WINDS BEHIND THE EXITING HIGH PRESSURE. MUCH WARMER
TEMPERATURES ARE THEN EXPECTED TUESDAY...WITH HIGH TEMPERATURES
EXPECTED TO CLIMB WELL ABOVE NORMAL INTO THE 80S ACROSS THE WESTERN
FORECAST AREA. THERE IS MUCH LESS CERTAINTY WITH TEMPERATURES IN THE
EAST THOUGH. MODELS VARY A BIT ON THE TIMING OF THE SYSTEM...THUS
IMPACTING WIND DIRECTION. IF THE WINDS STAY SOUTHEAST THROUGH THE
DAY AS THE SLOWER ECMWF SUGGESTS...HIGH TEMPS WILL LIKELY BE COOLER
THAN WHAT IS CURRENTLY FORECAST. THE QUICKER NAM AND CANADIAN WOULD
HAVE SOUTHWEST WINDS FOR A GOOD PART OF THE DAY...RESULTING IN
WARMER TEMPS THAN FORECAST. OPTED TO GO DOWN THE MIDDLE FOR TEMPS
TOWARD THE LAKE FOR NOW UNTIL MODELS COME INTO BETTER AGREEMENT.
THOUGH THE SURFACE FRONT WILL LIKELY HAVE PUSHED SOUTH BY WEDNESDAY
MORNING...MODELS ARE STILL SHOWING A FAIR AMOUNT OF WARM AIR
LINGERING ACROSS SOUTHERN WISCONSIN. HIGH TEMPS ARE THUS EXPECTED TO
REMAIN ABOVE NORMAL.
THURSDAY THROUGH SATURDAY...FORECAST CONFIDENCE...LOW TO MEDIUM
HAVE SHOWER AND STORM CHANCES THROUGH THE LATTER HALF OF THE WEEK AS
MODELS CONTINUE TO SHOW THE FRONTAL BOUNDARY STALLING IN THE AREA.
WILL LIKELY SEE SYSTEMS MOVE THROUGH ALONG THE BOUNDARY. BIGGEST
ISSUE IS HOW FAR SOUTH THE BOUNDARY WILL STALL AND THEN TIMING OF
THE INDIVIDUAL SYSTEMS AND RESULTANT PRECIP CHANCES.
ALSO...DIFFERING PLACEMENTS OF THE STALLED FRONT ARE PRODUCING
DECENT SPREADS IN TEMPS AMONG MODELS. NOT A HIGH CONFIDENCE
SETUP...SO STUCK WITH A CONSENSUS APPROACH FOR TEMPERATURES.
AVIATION/12Z TAFS/...
SHOULD SEE VFR CU DEVELOP/4-5K FT/ BY MID-MORNING AND BECOME BROKEN.
WINDS WILL BE GUSTY TO START AFTER MORNING MIX OUT...THEN SLOWLY
SUBSIDE THROUGH THE AFTERNOON AND REALLY EASE THIS EVENING AS
SURFACE RIDGE BUILDS INTO THE AREA. VFR FOR REMAINDER OF THE PERIOD
WITH LIGHT WINDS AND CLEAR SKIES TONIGHT.
MARINE...
CURRENT FORECAST WIND GUSTS STILL INDICATE 3 PM CDT END TIME FOR
SMALL CRAFT ADVISORY HOLDS...THOUGH THERE COULD BE A FEW CRITERIA
GUSTS UNTIL AFTER SUNSET...ESPECIALLY IN THE NORTHERN ZONES. WINDS
WILL EASE TONIGHT AS SURFACE RIDGE PASSES THROUGH...TURNING SOUTH
MONDAY AFTERNOON AND INCREASING MONDAY NIGHT AHEAD OF NEXT LOW.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...FROST ADVISORY FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ051-052-
057>060-062>072.
FREEZE WARNING FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ046-047-056.
LM...SMALL CRAFT ADVISORY UNTIL 3 PM CDT THIS AFTERNOON FOR
LMZ643>646.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...REM
MONDAY THROUGH SATURDAY...DDV
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
611 AM CDT SUN MAY 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT SUN MAY 12 2013
MAIN FORECAST CONCERN IS ON FROST/FREEZE CONDITIONS TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE WESTERN U.S. INTO ALBERTA WHILE ANOMALOUSLY
DEEP TROUGHING WAS PRESENT FROM HUDSON BAY INTO THE WESTERN GREAT
LAKES REGION. THE FORECAST AREA LIES ON THE BACK SIDE OF THE
TROUGHING...BUT STILL EAST OF THE INFLECTION POINT...WHICH RESULTS
IN NORTHWEST FLOW FROM THE SURFACE TO 500MB. THE FLOW CONTINUED TO
DRAG COLDER AIR SOUTHEAST WITH RAP 850MB TEMPS RANGING FROM -3C OVER
NORTHEAST IOWA TO -9C IN TAYLOR COUNTY WISCONSIN. DESPITE THE COLD
850MB TEMPS...READINGS ARE GENERALLY IN THE MID 30S TO AROUND 40...
STAYING UP BECAUSE OF THAT NORTHWEST WIND OF 5-10 KT AT THE SURFACE
KEEPING THE BOUNDARY LAYER MIXED. A LOT OF DRY AIR CONTINUES TO FLOW
IN TOO ON THE NORTHWEST WINDS FROM HIGH PRESSURE IN THE PLAINS.
DEWPOINTS ARE IN THE TEENS ACROSS MUCH OF THE DAKOTAS INTO MN AND
20S OVER WISCONSIN. COMBINATION OF THE WIND...TEMPERATURES AND DRY
AIR PRECLUDING ANY FROST DEVELOPMENT THUS FAR. THE AFOREMENTIONED
DRY AIR IS ALSO QUITE DEEP...REFLECTIVE FROM 00Z SOUNDINGS AT BIS...
ABR AND MPX HAVING PRECIPITABLE WATER VALUES OF 0.1-0.2 INCHES...OR
20-40 PERCENT OF NORMAL. THIS DRY AIR HAS HELPED CLEAR SKIES OUT
WEST OF WISCONSIN. SCT-BKN CLOUDS HAVE BEEN FLOWING ACROSS WISCONSIN
IN THE CYCLONIC FLOW IN THE UPPER TROUGH. FARTHER TO THE WEST UNDER
THE UPPER RIDGE...00Z SOUNDINGS FROM SAN FRANSISCO TO SALT LAKE CITY
AND NORTH TO GREAT FALLS MT ALL REPORTED 850MB TEMPS OF 20C OR
GREATER. THESE ARE 1.5-2.5 STANDARD DEVIATIONS ABOVE NORMAL.
BOTH THE UPPER RIDGE AND ANOMALOUSLY DEEP TROUGH ARE PROGGED TO
PROGRESS EASTWARD DURING THE NEXT 24 HOURS...PUSHED ALONG BY A
FAIRLY POTENT SHORTWAVE TROUGH APPROACHING THE PACIFIC NORTHWEST
COAST AT 12Z MONDAY. IT APPEARS THIS EVENING IS WHEN THE INFLECTION
POINT BETWEEN THE UPPER RIDGE AND DEEP TROUGH WILL REACH THE
FORECAST AREA. THIS MEANS TO PLAN ON THE SURFACE HIGH OVERHEAD AT
ABOUT THE SAME TIME.
TODAY...THE COMBINATION OF DRY AIR AND BEING FARTHER AWAY FROM THE
COLD POOL OF THE UPPER TROUGH WILL RESULT IN SUNNY SKIES. SINCE THE
AREA STAYS IN A GRADIENT AHEAD OF THE SURFACE HIGH AND WE HAVE FULL
SUN FOR DEEP MIXING...ANOTHER BREEZY DAY IS LIKELY...BUT NOT NEARLY
AS WINDY AS YESTERDAY. TEMPERATURES ARE DEFINITELY GOING TO STAY ON
THE COOL SIDE...THOUGH...WITH 850MB TEMPS HOLDING STEADY THROUGH
18Z. HIGHS SHOULD END UP VERY SIMILAR TO YESTERDAY.
TONIGHT...A REALLY GOOD RADIATIONAL COOLING SETUP IS FORECAST. WITH
THE SURFACE HIGH MOVING OVER THE AREA DURING THE EVENING...WINDS
WILL DECOUPLE EVERYWHERE. ADDITIONALLY...WE HAVE ALL OF THE DRY AIR
ACCOMPANYING THE SURFACE HIGH. THUS...TEMPERATURES SHOULD PLUMMET
DURING THE EVENING HOURS AFTER SUNSET. NOW...AFTER MIDNIGHT...THE
SURFACE RIDGE BEGINS TO PUSH EAST INTO CENTRAL WISCONSIN. THIS MEANS
A SOUTHERLY WARM ADVECTION FLOW WILL COMMENCE OVER WESTERN PORTIONS
OF THE FORECAST AREA. THEREFORE...OUR WISCONSIN COUNTIES CONTINUE TO
LOOK THE MOST FAVORABLE FOR THE COLDEST CONDITIONS...AND THE COLDEST
OVERALL OVER CENTRAL WISCONSIN. STAYED TOWARDS THE COLD SIDE OF
GUIDANCE FOR LOWS. GIVEN THE CONSISTENCY FOR TONIGHT TO BE COLD...
HAVE ISSUED FREEZE WARNINGS FOR THE PREVIOUS FREEZE WATCH AREA AND A
FEW EXTRA COUNTIES WHERE TEMPS ARE NOW FORECAST COLDER...WITH FROST
ADVISORIES FOR THE REST OF OUR WISCONSIN COUNTIES.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 320 AM CDT SUN MAY 12 2013
MONDAY THROUGH TUESDAY NIGHT...THE UPPER RIDGING OVER THE WESTERN
U.S. IS PROGGED TO CONTINUE TO GET PUSHED EASTWARD WHILE FLATTENING
WITH TIME. THIS IN RESPONSE TO THE POTENT SHORTWAVE OFF THE PACIFIC
NORTHWEST AT 12Z MONDAY TRACKING EASTWARD ALONG THE U.S./CANADIAN
BORDER. OVERALL MODELS ARE IN PRETTY GOOD AGREEMENT ON THE TRACK AND
SPEED OF THIS SHORTWAVE...WITH THE EXCEPTION OF THE 12.00Z NAM
WHICH BECOMES SLIGHTLY FASTER COME TUESDAY AND TUESDAY NIGHT. HAVE
DISCOUNTED THE NAM PROGRESSION AS AN OUTLIER FOR NOW. THE
PROGRESSIVE NATURE OF THE RIDGE AND SHORTWAVE RESULTS IN A VARIETY
OF ISSUES TO CONTEND WITH...
1. PRECIPITATION CHANCES AND TEMPERATURES MONDAY INTO MONDAY NIGHT.
A WARM FRONT AHEAD OF THE UPPER RIDGE AXIS IS FORECAST TO CROSS THE
AREA MONDAY NIGHT. PACIFIC MOISTURE MOVING THROUGH THE UPPER RIDGE
IN CONJUNCTION WITH ISENTROPIC LIFT AHEAD OF THIS WARM FRONT WILL
LIKELY TO LEAD TO EXTENSIVE MID AND HIGH CLOUDS. ADDITIONALLY...THE
LIFT APPEARS STRONG ENOUGH TO GENERATE PRECIPITATION FROM THESE
CLOUDS. THE BIG PROBLEM...THOUGH...IS LOW LEVEL DRY AIR LEFT OVER
FROM THE CURRENT CANADIAN HIGH PRESSURE AREA. OVERALL...12.00Z MODEL
GUIDANCE HAS BACKED OFF ON THE AMOUNT OF QPF POSSIBLE FROM THESE
CLOUDS...ESPECIALLY THE GFS...SUGGESTING THE DRY AIR MAY BE ABLE TO
ABSORB MUCH OF THE PRECIPITATION. HOWEVER...ALL GUIDANCE DOES
SUGGEST SOME LIGHT QPF POSSIBLE...THUS THE 20-40 PERCENT CHANCES
FROM THE PREVIOUS FORECAST STILL SEEMS REASONABLE. TIMING BETWEEN
18Z MONDAY TO 06Z TUESDAY ALSO STILL LOOKS GOOD. SHOULD SEE THE
CLOUDS AND PRECIPITATION PROGRESS EASTWARD THROUGH TIME DUE TO THE
PROGRESSION OF THE UPPER RIDGE. THE CLOUDS COMBINED WITH 850MB TEMPS
AT 18Z MONDAY OF 1C EAST TO 6C WEST ARE LIKELY TO KEEP TEMPERATURES
BELOW NORMAL...BUT NOT AS COLD AS TODAY.
2. HOW WARM TEMPERATURES WILL GET ON TUESDAY. THE SIGNAL OF A
CHINOOK WARM FRONT OFF THE ROCKIES...ACCOMPANYING THAT POTENT
SHORTWAVE...REMAINS FORECAST TO PUSH EAST THROUGH MUCH OF THE
FORECAST AREA DURING THE DAY TUESDAY. INCREDIBLY WARM 850MB TEMPS
FOR MID MAY ARE PROGGED TO FOLLOW IN ITS WAKE...WITH READINGS BY 00Z
OF 18-20C OVER CENTRAL WISCONSIN TO 22-24C WEST OF THE MISSISSIPPI
RIVER...OR 2 TO 3 STANDARD DEVIATIONS ABOVE NORMAL. SEEING THE
OBSERVED 850MB TEMPS UNDER THE UPPER RIDGE RIGHT NOW OVER THE
WESTERN U.S...THESE SEEM REASONABLE. THE QUESTION IS WITH A WARM
ADVECTION PATTERN THROUGH THE DAY...CAN WE MIX TO THESE 850MB TEMPS.
MODELS CONTINUE TO BE NOTORIOUSLY HIGH WITH SURFACE DEWPOINTS IN
THIS SITUATION...PREVENTING MODELS FROM MIXING ENOUGH. FOR
EXAMPLE...THE 12.00Z GFS/ECMWF/CANADIAN JUMP THEM OVER IOWA FROM
50-55 AT 12Z TO 60-65 AT 18Z...ALL LIKELY DUE TO EVAPOTRANSPORATION
THAT IS NOT THERE YET. ADDITIONALLY...A DOWNSLOPE FLOW FROM THE
ROCKIES USUALLY ENDS UP WITH DRIER DEWPOINTS...ESPECIALLY THIS TIME
OF YEAR. THUS...HAVE CONTINUED TO STAY TOWARDS THE WARM SIDE OF
GUIDANCE. ALTHOUGH THE 12.00Z NAM IS SLIGHTLY TOO PROGRESSIVE...ITS
TEMPERATURES SEEM REASONABLE. FOLLOWED MOS GUIDANCE MORE FOR
DEWPOINTS SINCE MOS HAS BEEN DOING MUCH BETTER IN THIS DEPARTMENT.
3. COLD FRONT CROSSING TUESDAY NIGHT AND POTENTIAL FOR PRECIPITATION
WITH IT. 12.00Z NAM AND GFS ARE JUST SLIGHTLY FARTHER SOUTH WITH THE
TRACK OF THE SHORTWAVE TRACKING ALONG THE CANADIAN BORDER...COMPARED
TO THE 12.00Z ECMWF/UKMET/CANADIAN. THIS DIFFERENCE RESULTS IN THE
NAM/GFS ADDING EXTRA FORCING TO THE LOW LEVEL FRONTOGENESIS ZONE ON
AND BEHIND THE COLD FRONT...AND THUS THE MODELS PRODUCE A BAND OF
PRECIPITATION OVER THE AREA. THE ECMWF/UKMET/CANADIAN ARE DRY. FEEL
THE LATTER MODEL GROUP IS MORE LIKELY TO OCCUR...BUT CONTINUED TO
HONOR THE NAM/GFS SCENARIO WITH A 20 PERCENT CHANCE JUST IN CASE.
WEDNESDAY INTO NEXT WEEKEND...
GOOD MODEL AGREEMENT EXISTS OF THE FLOW STARTING OFF AS ZONAL TO
BEGIN THIS PERIOD. ANY LOW LEVEL FRONTOGENETICAL FORCING BEHIND
TUESDAY NIGHTS COLD FRONT IS SOUTH OF THE AREA FOR WEDNESDAY...SO
WENT DRY DURING THIS TIME. THE ZONAL FLOW DOES NOT LAST LONG...WITH
A NEW TROUGH PROGGED TO COME INTO THE PACIFIC NORTHWEST THURSDAY
NIGHT. THIS CAUSES THE FLOW DOWNSTREAM TO BUCKLE...WITH THE 12.00Z
ECMWF/GFS/CANADIAN ALL SHOWING A SHORTWAVE TROUGH TRACKING ACROSS MN
AND WI THURSDAY INTO THURSDAY NIGHT. HAVE HONORED THE SHORTWAVE WITH
SOME SMALL CHANCES OF PRECIPITATION. WE COULD END UP WITH A DRY DAY
FRIDAY WITH SUBSIDENCE AND HIGH PRESSURE BUILDING IN. LOWERED
PRECIPITATION CHANCES FURTHER AND MAY BE ABLE TO COMPLETELY PULL
THEM WITH THE NEXT EXTENDED FORECAST UPDATE. THINGS LOOK TO PERHAPS
TO GET MORE ACTIVE FOR FRIDAY NIGHT INTO THE WEEKEND AS THE PACIFIC
NORTHWEST TROUGH BEGINS TO APPROACH THE PLAINS. SURPRISINGLY GOOD
MODEL AGREEMENT BETWEEN THE ECMWF AND GFS...ALONG WITH PREVIOUS
RUNS...OF A DEEPENING LOW DOWNSTREAM OVER NEBRASKA. AS ONE WOULD
EXPECT...A SURGE OF MOISTURE TRANSPORT OUT OF THE GULF OF MEXICO IS
AIMED DIRECTLY TOWARDS THE FORECAST AREA AHEAD OF THE LOW.
THUS...PRECIPITATION CHANCES INCREASE...ESPECIALLY ON SATURDAY WHERE
THE CONSENSUS EVEN RESULTS IN 50-60 PROBABILITIES. TEMPERATURES
SHOULD SLOWLY COOL THROUGH THE EXTENDED...BUT STILL STAY AT OR ABOVE
NORMAL WITH A FLOW GENERALLY OFF THE PACIFIC.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 611 AM CDT SUN MAY 12 2013
PLAN ON VFR CONDITIONS AT KLSE/KRST TODAY THROUGH TONIGHT AS HIGH
PRESSURE BUILDS INTO THE AREA. LOOK FOR BREEZY NORTHWEST WINDS
TODAY IN THE 12-20KT RANGE...TAPERING OFF AFTER SUNSET.
&&
.FIRE WEATHER...TUESDAY
ISSUED AT 320 AM CDT SUN MAY 12 2013
AFTER HAVING BREEZY...DRYING AND UNSEASONABLY COOL WEATHER THIS
WEEKEND...INCLUDING FROST/FREEZE CONDITIONS TONIGHT ACROSS
WISCONSIN...CONCERN CONTINUES TO INCREASE ABOUT CRITICAL FIRE
WEATHER CONDITIONS ON TUESDAY. MOST LOCATIONS SHOULD SEE HIGHS
CLIMB INTO THE 80S...WITH SOME WEST OF THE MISSISSIPPI RIVER
REACHING 90. DEWPOINT FORECASTS REMAIN TRICKY...BUT MINIMUM
RELATIVE HUMIDITY VALUES SHOULD HAVE NO PROBLEM FALLING INTO THE
30 TO 40 PERCENT RANGE. IT IS POSSIBLE LOCATIONS SAY ALONG AND
WEST OF US-52 COULD END UP DROPPING TOWARDS 25 PERCENT. COMBINED
WITH SOUTHWEST WINDS OF 15 TO 20 MPH AND HIGHER GUSTS...THE
SITUATION BEARS WATCHING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FROST ADVISORY FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ032-041-054-
061.
FREEZE WARNING FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ017-029-033-
034-042>044-053-055.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
345 AM CDT SUN MAY 12 2013
.TODAY...FORECAST CONFIDENCE...MEDIUM TO HIGH
NOT AS MUCH INSTABILITY OR DYNAMIC PUNCH AS THERE WAS
YESTERDAY...BUT STILL HAVE THE THE WESTERN EDGE OF THE COLD POOL
OVER US...ESPECIALLY OVER THE EASTERN CWA THIS MORNING. SHOULD SEE
CU POP BY MID MORNING. RAP SOUNDINGS SHOW A DEEPER CLOUD LAYER
THAN NAM OR GFS...WITH SOME MINIMAL CAPE DEVELOPING SOME SPRINKLES
IN THE SOUTHEAST IN THE AFTERNOON. WILL LEAVE OUT FOR NOW...BUT
WILL NEED TO BE WATCHED WITH SHEARED VORT DROPPING THROUGH REGION
THIS AFTERNOON PROVIDING A BIT OF EXTRA LIFT. THE COLD AIR
ADVECTION HAS BROUGHT 925 MB TEMPERATURES DOWN TO -1C TO -4C...BUT
MODELS AGREE THAT THEY WILL RECOVER TO +3 TO +5C BY 00Z. THOUGH
WARMEST 925 MB TEMPS WILL ARRIVE TOWARD THE END OF THE
DAY...ENOUGH OF AN INFLUENCE TO LEAN TOWARD WARMER GUIDANCE WITH
MID 50S IN THE WEST...TO AROUND 50 IN THE FAR EAST.
.TONIGHT...FORECAST CONFIDENCE...HIGH
GIVEN THE EXPECTED GOOD RADIATIONAL COOLING CONDITIONS AS SURFACE
RIDGE AXIS MOVES OVER THE STATE TONIGHT ...AND WITH BUFKIT SOUNDINGS
SUPPORTING THE THE NAM/GFS 2-METER TEMPERATURES AND MOS GUIDANCE...
WILL ISSUE A FREEZE WARNING FOR THE FAR NW COUNTIES WHERE LOWS TO
BOTTOM OUT IN THE UPPER 20S...AND A FROST ADVISORY FOR THE REST OF
THE CWA WITH LOW 30S AWAY FROM THE IMMEDIATE LAKESHORE. EVEN
MILWAUKEE AND OZAUKEE COUNTIES SHOULD SEE AREAS OF FROST IN THEIR
FAR WEST. THE LOWEST TEMPERATURES ARE CURRENTLY LIMITED TO NORTHERN
SECTIONS OF THE FREEZE WARNING COUNTIES...BUT WARNING WOULD HAVE TO
BE EXPANDED IF THE COLDER NAM IS CORRECT.
.MONDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE...MEDIUM
THE AXIS OF SURFACE HIGH PRESSURE WILL BE OVERHEAD MONDAY
MORNING...SO THERE SHOULD BE PLENTY OF SUNSHINE TO START THE DAY.
THE HIGH WILL SLIDE EAST DURING THE DAY...WITH STRONG WARM ADVECTION
ALOFT SLIDING INTO THE WEST BY LATE AFTERNOON. THIS WILL BRING
INCREASING CLOUDS ALONG WITH A CHANCE FOR SHOWERS TO MAINLY WESTERN
PORTIONS OF THE FORECAST AREA.
THE MAX OF THE WARM ADVECTION WILL SLIDE THROUGH MAINLY DURING THE
EVENING HOURS...SO KEPT HIGHEST POPS DURING THAT PERIOD. SHOULD BE
MAINLY DRY THEN TUESDAY AS A WARMER AND CAPPED AIRMASS MOVES INTO
THE FORECAST AREA.
THE SURFACE COLD FRONT IS EXPECTED TO DROP THROUGH SOUTHERN
WISCONSIN TUESDAY EVENING AND OVERNIGHT. MODELS ARE NOT SHOWING MUCH
LIFT WITH THIS FRONT...SO KEPT POPS ON THE LOW END.
TEMPERATURES MONDAY WILL CLIMB BACK TOWARD NORMAL VALUES UNDER
SOUTHERLY WINDS BEHIND THE EXITING HIGH PRESSURE. MUCH WARMER
TEMPERATURES ARE THEN EXPECTED TUESDAY...WITH HIGH TEMPERATURES
EXPECTED TO CLIMB WELL ABOVE NORMAL INTO THE 80S ACROSS THE WESTERN
FORECAST AREA. THERE IS MUCH LESS CERTAINTY WITH TEMPERATURES IN THE
EAST THOUGH. MODELS VARY A BIT ON THE TIMING OF THE SYSTEM...THUS
IMPACTING WIND DIRECTION. IF THE WINDS STAY SOUTHEAST THROUGH THE
DAY AS THE SLOWER ECMWF SUGGESTS...HIGH TEMPS WILL LIKELY BE COOLER
THAN WHAT IS CURRENTLY FORECAST. THE QUICKER NAM AND CANADIAN WOULD
HAVE SOUTHWEST WINDS FOR A GOOD PART OF THE DAY...RESULTING IN
WARMER TEMPS THAN FORECAST. OPTED TO GO DOWN THE MIDDLE FOR TEMPS
TOWARD THE LAKE FOR NOW UNTIL MODELS COME INTO BETTER AGREEMENT.
THOUGH THE SURFACE FRONT WILL LIKELY HAVE PUSHED SOUTH BY WEDNESDAY
MORNING...MODELS ARE STILL SHOWING A FAIR AMOUNT OF WARM AIR
LINGERING ACROSS SOUTHERN WISCONSIN. HIGH TEMPS ARE THUS EXPECTED TO
REMAIN ABOVE NORMAL.
.THURSDAY THROUGH SATURDAY...FORECAST CONFIDENCE...LOW TO MEDIUM
HAVE SHOWER AND STORM CHANCES THROUGH THE LATTER HALF OF THE WEEK AS
MODELS CONTINUE TO SHOW THE FRONTAL BOUNDARY STALLING IN THE AREA.
WILL LIKELY SEE SYSTEMS MOVE THROUGH ALONG THE BOUNDARY. BIGGEST
ISSUE IS HOW FAR SOUTH THE BOUNDARY WILL STALL AND THEN TIMING OF
THE INDIVIDUAL SYSTEMS AND RESULTANT PRECIP CHANCES.
ALSO...DIFFERING PLACEMENTS OF THE STALLED FRONT ARE PRODUCING
DECENT SPREADS IN TEMPS AMONG MODELS. NOT A HIGH CONFIDENCE
SETUP...SO STUCK WITH A CONSENSUS APPROACH FOR TEMPERATURES.
&&
.AVIATION/12Z TAFS/...
SHOULD SEE VFR CU DEVELOP/4-5K FT/ BY MID-MORNING AND BECOME BROKEN.
WINDS WILL BE GUSTY TO START AFTER MORNING MIX OUT...THEN SLOWLY
SUBSIDE THROUGH THE AFTERNOON AND REALLY EASE THIS EVENING AS
SURFACE RIDGE BUILDS INTO THE AREA. VFR FOR REMAINDER OF THE PERIOD
WITH LIGHT WINDS AND CLEAR SKIES TONIGHT.
&&
.MARINE...
CURRENT FORECAST WIND GUSTS STILL INDICATE 3 PM CDT END TIME FOR
SMALL CRAFT ADVISORY HOLDS...THOUGH THERE COULD BE A FEW CRITERIA
GUSTS UNTIL AFTER SUNSET...ESPECIALLY IN THE NORTHERN ZONES. WINDS
WILL EASE TONIGHT AS SURFACE RIDGE PASSES THROUGH...TURNING SOUTH
MONDAY AFTERNOON AND INCREASING MONDAY NIGHT AHEAD OF NEXT LOW.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...FROST ADVISORY FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ051-052-
057>060-062>072.
FREEZE WARNING FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ046-047-056.
LM...SMALL CRAFT ADVISORY UNTIL 3 PM CDT THIS AFTERNOON FOR
LMZ643>646.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...REM
MONDAY THROUGH SATURDAY...DDV
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
320 AM CDT SUN MAY 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT SUN MAY 12 2013
MAIN FORECAST CONCERN IS ON FROST/FREEZE CONDITIONS TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE WESTERN U.S. INTO ALBERTA WHILE ANOMALOUSLY
DEEP TROUGHING WAS PRESENT FROM HUDSON BAY INTO THE WESTERN GREAT
LAKES REGION. THE FORECAST AREA LIES ON THE BACK SIDE OF THE
TROUGHING...BUT STILL EAST OF THE INFLECTION POINT...WHICH RESULTS
IN NORTHWEST FLOW FROM THE SURFACE TO 500MB. THE FLOW CONTINUED TO
DRAG COLDER AIR SOUTHEAST WITH RAP 850MB TEMPS RANGING FROM -3C OVER
NORTHEAST IOWA TO -9C IN TAYLOR COUNTY WISCONSIN. DESPITE THE COLD
850MB TEMPS...READINGS ARE GENERALLY IN THE MID 30S TO AROUND 40...
STAYING UP BECAUSE OF THAT NORTHWEST WIND OF 5-10 KT AT THE SURFACE
KEEPING THE BOUNDARY LAYER MIXED. A LOT OF DRY AIR CONTINUES TO FLOW
IN TOO ON THE NORTHWEST WINDS FROM HIGH PRESSURE IN THE PLAINS.
DEWPOINTS ARE IN THE TEENS ACROSS MUCH OF THE DAKOTAS INTO MN AND
20S OVER WISCONSIN. COMBINATION OF THE WIND...TEMPERATURES AND DRY
AIR PRECLUDING ANY FROST DEVELOPMENT THUS FAR. THE AFOREMENTIONED
DRY AIR IS ALSO QUITE DEEP...REFLECTIVE FROM 00Z SOUNDINGS AT BIS...
ABR AND MPX HAVING PRECIPITABLE WATER VALUES OF 0.1-0.2 INCHES...OR
20-40 PERCENT OF NORMAL. THIS DRY AIR HAS HELPED CLEAR SKIES OUT
WEST OF WISCONSIN. SCT-BKN CLOUDS HAVE BEEN FLOWING ACROSS WISCONSIN
IN THE CYCLONIC FLOW IN THE UPPER TROUGH. FARTHER TO THE WEST UNDER
THE UPPER RIDGE...00Z SOUNDINGS FROM SAN FRANSISCO TO SALT LAKE CITY
AND NORTH TO GREAT FALLS MT ALL REPORTED 850MB TEMPS OF 20C OR
GREATER. THESE ARE 1.5-2.5 STANDARD DEVIATIONS ABOVE NORMAL.
BOTH THE UPPER RIDGE AND ANOMALOUSLY DEEP TROUGH ARE PROGGED TO
PROGRESS EASTWARD DURING THE NEXT 24 HOURS...PUSHED ALONG BY A
FAIRLY POTENT SHORTWAVE TROUGH APPROACHING THE PACIFIC NORTHWEST
COAST AT 12Z MONDAY. IT APPEARS THIS EVENING IS WHEN THE INFLECTION
POINT BETWEEN THE UPPER RIDGE AND DEEP TROUGH WILL REACH THE
FORECAST AREA. THIS MEANS TO PLAN ON THE SURFACE HIGH OVERHEAD AT
ABOUT THE SAME TIME.
TODAY...THE COMBINATION OF DRY AIR AND BEING FARTHER AWAY FROM THE
COLD POOL OF THE UPPER TROUGH WILL RESULT IN SUNNY SKIES. SINCE THE
AREA STAYS IN A GRADIENT AHEAD OF THE SURFACE HIGH AND WE HAVE FULL
SUN FOR DEEP MIXING...ANOTHER BREEZY DAY IS LIKELY...BUT NOT NEARLY
AS WINDY AS YESTERDAY. TEMPERATURES ARE DEFINITELY GOING TO STAY ON
THE COOL SIDE...THOUGH...WITH 850MB TEMPS HOLDING STEADY THROUGH
18Z. HIGHS SHOULD END UP VERY SIMILAR TO YESTERDAY.
TONIGHT...A REALLY GOOD RADIATIONAL COOLING SETUP IS FORECAST. WITH
THE SURFACE HIGH MOVING OVER THE AREA DURING THE EVENING...WINDS
WILL DECOUPLE EVERYWHERE. ADDITIONALLY...WE HAVE ALL OF THE DRY AIR
ACCOMPANYING THE SURFACE HIGH. THUS...TEMPERATURES SHOULD PLUMMET
DURING THE EVENING HOURS AFTER SUNSET. NOW...AFTER MIDNIGHT...THE
SURFACE RIDGE BEGINS TO PUSH EAST INTO CENTRAL WISCONSIN. THIS MEANS
A SOUTHERLY WARM ADVECTION FLOW WILL COMMENCE OVER WESTERN PORTIONS
OF THE FORECAST AREA. THEREFORE...OUR WISCONSIN COUNTIES CONTINUE TO
LOOK THE MOST FAVORABLE FOR THE COLDEST CONDITIONS...AND THE COLDEST
OVERALL OVER CENTRAL WISCONSIN. STAYED TOWARDS THE COLD SIDE OF
GUIDANCE FOR LOWS. GIVEN THE CONSISTENCY FOR TONIGHT TO BE COLD...
HAVE ISSUED FREEZE WARNINGS FOR THE PREVIOUS FREEZE WATCH AREA AND A
FEW EXTRA COUNTIES WHERE TEMPS ARE NOW FORECAST COLDER...WITH FROST
ADVISORIES FOR THE REST OF OUR WISCONSIN COUNTIES.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 320 AM CDT SUN MAY 12 2013
MONDAY THROUGH TUESDAY NIGHT...THE UPPER RIDGING OVER THE WESTERN
U.S. IS PROGGED TO CONTINUE TO GET PUSHED EASTWARD WHILE FLATTENING
WITH TIME. THIS IN RESPONSE TO THE POTENT SHORTWAVE OFF THE PACIFIC
NORTHWEST AT 12Z MONDAY TRACKING EASTWARD ALONG THE U.S./CANADIAN
BORDER. OVERALL MODELS ARE IN PRETTY GOOD AGREEMENT ON THE TRACK AND
SPEED OF THIS SHORTWAVE...WITH THE EXCEPTION OF THE 12.00Z NAM
WHICH BECOMES SLIGHTLY FASTER COME TUESDAY AND TUESDAY NIGHT. HAVE
DISCOUNTED THE NAM PROGRESSION AS AN OUTLIER FOR NOW. THE
PROGRESSIVE NATURE OF THE RIDGE AND SHORTWAVE RESULTS IN A VARIETY
OF ISSUES TO CONTEND WITH...
1. PRECIPITATION CHANCES AND TEMPERATURES MONDAY INTO MONDAY NIGHT.
A WARM FRONT AHEAD OF THE UPPER RIDGE AXIS IS FORECAST TO CROSS THE
AREA MONDAY NIGHT. PACIFIC MOISTURE MOVING THROUGH THE UPPER RIDGE
IN CONJUNCTION WITH ISENTROPIC LIFT AHEAD OF THIS WARM FRONT WILL
LIKELY TO LEAD TO EXTENSIVE MID AND HIGH CLOUDS. ADDITIONALLY...THE
LIFT APPEARS STRONG ENOUGH TO GENERATE PRECIPITATION FROM THESE
CLOUDS. THE BIG PROBLEM...THOUGH...IS LOW LEVEL DRY AIR LEFT OVER
FROM THE CURRENT CANADIAN HIGH PRESSURE AREA. OVERALL...12.00Z MODEL
GUIDANCE HAS BACKED OFF ON THE AMOUNT OF QPF POSSIBLE FROM THESE
CLOUDS...ESPECIALLY THE GFS...SUGGESTING THE DRY AIR MAY BE ABLE TO
ABSORB MUCH OF THE PRECIPITATION. HOWEVER...ALL GUIDANCE DOES
SUGGEST SOME LIGHT QPF POSSIBLE...THUS THE 20-40 PERCENT CHANCES
FROM THE PREVIOUS FORECAST STILL SEEMS REASONABLE. TIMING BETWEEN
18Z MONDAY TO 06Z TUESDAY ALSO STILL LOOKS GOOD. SHOULD SEE THE
CLOUDS AND PRECIPITATION PROGRESS EASTWARD THROUGH TIME DUE TO THE
PROGRESSION OF THE UPPER RIDGE. THE CLOUDS COMBINED WITH 850MB TEMPS
AT 18Z MONDAY OF 1C EAST TO 6C WEST ARE LIKELY TO KEEP TEMPERATURES
BELOW NORMAL...BUT NOT AS COLD AS TODAY.
2. HOW WARM TEMPERATURES WILL GET ON TUESDAY. THE SIGNAL OF A
CHINOOK WARM FRONT OFF THE ROCKIES...ACCOMPANYING THAT POTENT
SHORTWAVE...REMAINS FORECAST TO PUSH EAST THROUGH MUCH OF THE
FORECAST AREA DURING THE DAY TUESDAY. INCREDIBLY WARM 850MB TEMPS
FOR MID MAY ARE PROGGED TO FOLLOW IN ITS WAKE...WITH READINGS BY 00Z
OF 18-20C OVER CENTRAL WISCONSIN TO 22-24C WEST OF THE MISSISSIPPI
RIVER...OR 2 TO 3 STANDARD DEVIATIONS ABOVE NORMAL. SEEING THE
OBSERVED 850MB TEMPS UNDER THE UPPER RIDGE RIGHT NOW OVER THE
WESTERN U.S...THESE SEEM REASONABLE. THE QUESTION IS WITH A WARM
ADVECTION PATTERN THROUGH THE DAY...CAN WE MIX TO THESE 850MB TEMPS.
MODELS CONTINUE TO BE NOTORIOUSLY HIGH WITH SURFACE DEWPOINTS IN
THIS SITUATION...PREVENTING MODELS FROM MIXING ENOUGH. FOR
EXAMPLE...THE 12.00Z GFS/ECMWF/CANADIAN JUMP THEM OVER IOWA FROM
50-55 AT 12Z TO 60-65 AT 18Z...ALL LIKELY DUE TO EVAPOTRANSPORATION
THAT IS NOT THERE YET. ADDITIONALLY...A DOWNSLOPE FLOW FROM THE
ROCKIES USUALLY ENDS UP WITH DRIER DEWPOINTS...ESPECIALLY THIS TIME
OF YEAR. THUS...HAVE CONTINUED TO STAY TOWARDS THE WARM SIDE OF
GUIDANCE. ALTHOUGH THE 12.00Z NAM IS SLIGHTLY TOO PROGRESSIVE...ITS
TEMPERATURES SEEM REASONABLE. FOLLOWED MOS GUIDANCE MORE FOR
DEWPOINTS SINCE MOS HAS BEEN DOING MUCH BETTER IN THIS DEPARTMENT.
3. COLD FRONT CROSSING TUESDAY NIGHT AND POTENTIAL FOR PRECIPITATION
WITH IT. 12.00Z NAM AND GFS ARE JUST SLIGHTLY FARTHER SOUTH WITH THE
TRACK OF THE SHORTWAVE TRACKING ALONG THE CANADIAN BORDER...COMPARED
TO THE 12.00Z ECMWF/UKMET/CANADIAN. THIS DIFFERENCE RESULTS IN THE
NAM/GFS ADDING EXTRA FORCING TO THE LOW LEVEL FRONTOGENESIS ZONE ON
AND BEHIND THE COLD FRONT...AND THUS THE MODELS PRODUCE A BAND OF
PRECIPITATION OVER THE AREA. THE ECMWF/UKMET/CANADIAN ARE DRY. FEEL
THE LATTER MODEL GROUP IS MORE LIKELY TO OCCUR...BUT CONTINUED TO
HONOR THE NAM/GFS SCENARIO WITH A 20 PERCENT CHANCE JUST IN CASE.
WEDNESDAY INTO NEXT WEEKEND...
GOOD MODEL AGREEMENT EXISTS OF THE FLOW STARTING OFF AS ZONAL TO
BEGIN THIS PERIOD. ANY LOW LEVEL FRONTOGENETICAL FORCING BEHIND
TUESDAY NIGHTS COLD FRONT IS SOUTH OF THE AREA FOR WEDNESDAY...SO
WENT DRY DURING THIS TIME. THE ZONAL FLOW DOES NOT LAST LONG...WITH
A NEW TROUGH PROGGED TO COME INTO THE PACIFIC NORTHWEST THURSDAY
NIGHT. THIS CAUSES THE FLOW DOWNSTREAM TO BUCKLE...WITH THE 12.00Z
ECMWF/GFS/CANADIAN ALL SHOWING A SHORTWAVE TROUGH TRACKING ACROSS MN
AND WI THURSDAY INTO THURSDAY NIGHT. HAVE HONORED THE SHORTWAVE WITH
SOME SMALL CHANCES OF PRECIPITATION. WE COULD END UP WITH A DRY DAY
FRIDAY WITH SUBSIDENCE AND HIGH PRESSURE BUILDING IN. LOWERED
PRECIPITATION CHANCES FURTHER AND MAY BE ABLE TO COMPLETELY PULL
THEM WITH THE NEXT EXTENDED FORECAST UPDATE. THINGS LOOK TO PERHAPS
TO GET MORE ACTIVE FOR FRIDAY NIGHT INTO THE WEEKEND AS THE PACIFIC
NORTHWEST TROUGH BEGINS TO APPROACH THE PLAINS. SURPRISINGLY GOOD
MODEL AGREEMENT BETWEEN THE ECMWF AND GFS...ALONG WITH PREVIOUS
RUNS...OF A DEEPENING LOW DOWNSTREAM OVER NEBRASKA. AS ONE WOULD
EXPECT...A SURGE OF MOISTURE TRANSPORT OUT OF THE GULF OF MEXICO IS
AIMED DIRECTLY TOWARDS THE FORECAST AREA AHEAD OF THE LOW.
THUS...PRECIPITATION CHANCES INCREASE...ESPECIALLY ON SATURDAY WHERE
THE CONSENSUS EVEN RESULTS IN 50-60 PROBABILITIES. TEMPERATURES
SHOULD SLOWLY COOL THROUGH THE EXTENDED...BUT STILL STAY AT OR ABOVE
NORMAL WITH A FLOW GENERALLY OFF THE PACIFIC.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1015 PM CDT SAT MAY 11 2013
CLOUDS AND -SHRA HAVE DISSIPATED FOR KRST/KLSE EARLY IN THE
EVENING...WHILE WINDS WERE LESSENING WITH THE LOSS OF MIXING FROM
DAYTIME HEATING. THE WINDS WILL CONTINUE TO DECREASE OVERNIGHT AS
HIGH PRESSURE APPROACHES FROM THE WEST...ALLOWING FOR THE SFC
PRESSURE GRADIENT TO SLACKEN. HOWEVER...EXPECTED SUNSHINE ON SUNDAY
WILL RESULT IN MORE MIXING. EXPECT SOME GUSTS SUNDAY AFTERNOON...BUT
ABOUT 1/2 OF WHAT THEY WERE TODAY. VFR CONDITIONS WILL BE THE RULE
THROUGH SUNDAY NIGHT AS THAT HIGH SETTLES OVERHEAD.
CLOUDS WILL RETURN ON MONDAY AS AN UPPER LEVEL SHORTWAVE TROUGH
MOVES ACROSS NORTHERN PORTIONS OF THE UPPER MISSISSIPPI RIVER
VALLEY. A FEW SHOWERS WILL DEVELOP ALONG ITS ASSOCIATED WARM
FRONT...BUT THESE SHOULD STAY NORTH OF KRST/KLSE. LOOK FOR MUCH
WARMER CONDITIONS FOR TUE/WED POST THE FRONT.
&&
.FIRE WEATHER...TUESDAY
ISSUED AT 320 AM CDT SUN MAY 12 2013
AFTER HAVING BREEZY...DRYING AND UNSEASONABLY COOL WEATHER THIS
WEEKEND...INCLUDING FROST/FREEZE CONDITIONS TONIGHT ACROSS
WISCONSIN...CONCERN CONTINUES TO INCREASE ABOUT CRITICAL FIRE
WEATHER CONDITIONS ON TUESDAY. MOST LOCATIONS SHOULD SEE HIGHS
CLIMB INTO THE 80S...WITH SOME WEST OF THE MISSISSIPPI RIVER
REACHING 90. DEWPOINT FORECASTS REMAIN TRICKY...BUT MINIMUM
RELATIVE HUMIDITY VALUES SHOULD HAVE NO PROBLEM FALLING INTO THE
30 TO 40 PERCENT RANGE. IT IS POSSIBLE LOCATIONS SAY ALONG AND
WEST OF US-52 COULD END UP DROPPING TOWARDS 25 PERCENT. COMBINED
WITH SOUTHWEST WINDS OF 15 TO 20 MPH AND HIGHER GUSTS...THE
SITUATION BEARS WATCHING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FROST ADVISORY FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ032-041-054-
061.
FREEZE WARNING FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ017-029-033-
034-042>044-053-055.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RIECK
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS TUCSON AZ
235 AM MST TUE MAY 14 2013
.SYNOPSIS...A WEAK LOW IN NORTHERN MEXICO WILL PUSH NORTHEAST
THROUGH THE AREA TODAY...WITH A CHANCE OF MAINLY MOUNTAIN
THUNDERSTORMS THIS AFTERNOON AND EVENING. OTHERWISE...TEMPERATURES
WILL CONTINUE TO HEAT UP DURING THE WORK WEEK WITH HIGHS NEAR 100
DEGREES IN THE LOWER DESERT LOCATIONS AND 90S ELSEWHERE. A STRONGER
SYSTEM WILL MOVE NORTH OF THE REGION THIS COMING WEEKEND...RESULTING
IN SEVERAL DEGREES OF COOLING AND BREEZY CONDITIONS.
&&
.DISCUSSION...SOME MID CLOUD ENHANCEMENT THIS MORNING ON THE
NORTHERN PERIPHERY OF THE WEAKENING LOW IN NORTHWEST MEXICO. A FEW
SPRINKLES REACHING THE GROUND UNDER MOSTLY VIRGA EARLY THIS MORNING.
SOME BOUNDARY LAYER MOISTURE INCREASE UNDER THE MID LEVEL
MOISTURE...AS THE LOW SHEARS INTO NEW MEXICO ON IT`S WAY TO HIGHER
LATITUDES OVER THE NEXT 12 TO 24 HOURS. WE SHOULD MANAGE ENOUGH
INSTABILITY FOR UNSEASONABLE MODERATE CONVECTIVE DEVELOPMENT OVER
THE MOUNTAINS AS REFLECTED BY LATEST HRRR AND NAMDNG5 TRENDS. LATEST
RAPID REFRESH AND PREVIOUS UOFAZ WRF OUTPUT SUGGEST DEVELOPING 250
TO 400 VALLEY CAPE THIS AFTERNOON. COMBINED WITH A LESS FAVORABLE
FLOW WE STILL DON`T EXPECT TO BE ABLE TO SUPPORT MUCH CONVECTION IN
MOST VALLEY LOCATIONS...HOWEVER SOME ORGANIZED OUTFLOW FROM
COLLAPSING STORMS AS THEY TRY TO PUSH INTO VALLEYS EXPECTED AND FEW
HUNDREDTHS HERE AND THERE NOT OUT OF THE QUESTION.
THE RIDGE CLEANS UP A BIT AS THIS WEAKNESS KICKS WELL NORTHEAST
TONIGHT...BUT LOSES GEOMETRY AS THE AXIS SHIFTS EAST OF US THURSDAY
WITH A DEVELOPING SYSTEM NEAR THE PACIFIC NORTHWEST. AFTER A PAUSE
IN THE HEATING TREND TODAY...WE`LL HAVE TIME TO JUMP BACK INTO
HOTTER TEMPERATURES WEDNESDAY AND THURSDAY BUT STILL HAVING A HARD
TIME JUSTIFYING THE FIRST 100 AT TIA...98 OR 99 IS ABOUT ALL WE CAN
CURRENTLY SQUEEZE OUT OF THE FORECASTED THICKNESS AND HEIGHT TRENDS.
TROUGH PUSHING THROUGH THE REGION FRIDAY INTO THE WEEKEND. AS ONE
MIGHT EXPECT FOR THE SECOND HALF OF MAY...DYNAMICS AND BEST MOISTURE
WELL NORTH OF OUR CWA BUT WE CAN EXPECT A MODEST COOLING TREND AND
GUSTY WINDS OUT OF THE SYSTEM.
WEAKENING RIDGE PHASING ACROSS THE AREA EARLY NEXT WEEK COULD BRING
THE FIRST 100 FOR TIA MONDAY OR TUESDAY IF WE CAN`T MANAGE IT THIS
WEEK.
&&
.AVIATION...SKC-SCT 12KFT AGL LCL BKN 10KFT AGL WITH ISOLD -SHRA.
FROM 14/20Z THRU 15/04Z SCT-BKN 12KFT WDLY SCTD -SHRA/TS BKN 8KFT
AGL...MAINLY E AND S OF KTUS. AFT 15/04Z...FEW-SCT LCLY BKN 10KFT
AGL. SFC WIND E-S 5-10 KTS WITH LCL GUSTS TO 18 KTS...FROM 14/19Z
THRU 15/04Z SFC WND W-S 8-15 KTS WITH OCNL GUSTS 18-24 KTS...HIGHER
GUSTS NR SHRA/TS E AND S OF KTUS...AFT 15/04Z WIND TERRAIN DRIVEN
LESS THAN 10 KTS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...A WEAK UPPER LOW OVER NORTHERN MEXICO WILL MOVE
NORTHEAST TODAY INTO THIS EVENING. ENOUGH MOISTURE IS AROUND FOR THE
DEVELOPMENT OF ISOLATED SHOWERS...POSSIBLY A THUNDERSTORM...FROM
TUCSON EAST AND SOUTH. WEAK RIDGE OF HIGH PRESSURE OVER THE AREA
WEDNESDAY AND THURSDAY BEFORE AN UPPER LEVEL TROUGH MOVES THROUGH
THE INTERMOUNTAIN WEST FRIDAY AND SATURDAY BRINGING BREEZY TO
LOCALLY WINDY CONDITIONS TO THE REGION.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
MEYER/GLUECK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
408 AM CDT TUE MAY 14 2013
.SHORT TERM.../TODAY /...
ISSUED AT 407 AM CDT TUE MAY 14 2013
FORECAST CHALLENGE TODAY IS WITH RECORD OR
NEAR RECORD HIGH MAX TEMPS...DEW POINTS AND WINDS. MODELS STILL
INITIALIZING TOO MOIST WITH THE RAP CONTINUING TO BE THE DRY
SOLUTION TODAY. RAP ALSO HAS THE BETTER HANDLE ON THE TEMPS
TODAY...SO LEANED CLOSER TO THE RAP SOLUTION.
WINDS WILL INCREASE LATE THIS MORNING AND CONTINUE TO MIX DURING THE
AFTERNOON WITH RAP SHOWING THE BEST DRY ADIABATIC SOUNDING. MIXING
TO 850MB SHOULD TAP INTO THE +25C TEMPERATURES ADVECTING INTO
WESTERN TO NORTHERN IOWA BY THIS AFTERNOON. NAM/GFS/ECMWF SOUNDINGS
ARE NOT AS AGGRESSIVE WITH THE MIXING TODAY...AND POSSIBLY ONE
REASON THESE MODELS OVERDOING THE DEW POINTS. TEMPS OVERNIGHT
REMAINING IN THE UPPER 50S/LOWER 60S ACROSS MUCH OF THE FORECAST
AREA...AND WITH THE NORTHWEST FORECAST AREA RISING 2-4 DEGREES
WARMER MONDAY THAN ANTICIPATED...CONFIDENT ENOUGH TO TWEAK MAX TEMPS
UP SLIGHTLY OVER THE WEST AND NORTH. WENT ROUGHLY 3 TO 5 DEGREES
ABOVE THE WARMEST GUIDANCE TODAY. WITH THE DRIER DEW POINTS AND RH
VALUES COMBINED WITH THE GUSTY SOUTHWEST WINDS...DECIDED TO UPGRADE
TO A RED FLAG WARNING. SEE FIRE WEATHER DISCUSSION FOR FURTHER
DETAILS.
.LONG TERM.../TONIGHT THROUGH MONDAY/...
ISSUED AT 400 AM CDT TUE MAY 14 2013
THE FRONTAL BOUNDARY WILL DROP SLOWLY SOUTH THROUGH THE STATE
OVERNIGHT BEFORE STALLING IN THE ZONAL FLOW JUST SOUTH INTO
MISSOURI ON WEDNESDAY. MOISTURE REMAINS QUITE LIMITED WITH THE
SYSTEM. ANY SHOWERS AND THUNDERSTORMS THAT DO FORM WILL BE
EXTREMELY HIGH BASED AND ABOVE THE PRIMARY AREA OF FORCING. THIS
COMBINED WITH THE LACK OF ASSOCIATED MOISTURE WILL KEEP ANY
ACTIVITY QUITE SPARSE. BROAD AREA OF LOW PRESSURE WILL BECOME
REFOCUSED OVER WYOMING AND THE WESTERN DAKOTAS THURSDAY INTO
FRIDAY. THIS WILL HELP DRIVE THE FRONTAL BOUNDARY BACK NORTH AS A
WARM FRONT. PRECIPITATION CHANCES WILL CONTINUE MAINLY OVER THE
SOUTH WEDNESDAY BEFORE SPREADING BACK NORTH WITH THE FRONTAL
PASSAGE THROUGH THE END OF THE WEEK.
HAVE MAINTAINED THUNDERSTORM CHANCES ON SATURDAY THOUGH THE SIGNS
BEGINNING TO POINT TO THE STATE BEING IN THE WARM SECTOR WITH THE
WARM FRONT MOVING NORTH OF THE STATE. WARM AIR ALOFT WOULD LEAVE A
FAIR AMOUNT OF CONVECTIVE INHIBITION TO OVERCOME ON SATURDAY.
BETTER CHANCE FOR THUNDERSTORMS AND POSSIBLY SEVERE WEATHER WOULD
BE SUNDAY AS A THE UPPER LEVEL RIDGE BEGINS TO BE SHOVED EAST BY
AN UPPER LEVEL SYSTEM ENTERING THE NORTHWESTERN CONUS. THIS WILL
INCREASE THE SOUTHWEST FLOW INTO THE STATE EARLY SUNDAY WITH A
COLD FRONT ARRIVING LATER IN THE DAY. CERTAINLY A FAVORABLE SETUP
FOR SURFACE BASED CONVECTION WITH THE PRIMARY THREATS OF WIND AND
HAIL WITH THE TRIPLE POINT WELL TO THE NORTH...BUT IT IS STILL
SEVERAL DAYS AWAY.
TEMPERATURES THROUGH THE PERIOD WILL BE SEASONAL TO ABOVE NORMAL.
POSSIBLY CLOUD COVER ON WEDNESDAY AND THURSDAY WILL HAVE AN IMPACT
ON TEMPERATURES. THURSDAY ESPECIALLY WILL BE COOLER THAN THE NORTH
DUE TO PRECIPITATION AND CLOUDS. LIKELY A RETURN TO THE 80S ON
SATURDAY WITH DEWPOINTS POSSIBLY RISING INTO THE 60S.
&&
.AVIATION...14/06Z
ISSUED AT 1145 PM CDT MON MAY 13 2013
VFR CONDITIONS THROUGH THE TAF PERIOD...WITH SOUTHERLY WINDS
INCREASING THROUGH THE DAY TUESDAY. WINDS TO BECOME MORE
SOUTHWESTERLY TO WESTERLY AS A FRONTAL BOUNDARY APPROACHES TUESDAY
EVENING. SCT-BKN150 HIGH CLOUDS POSSIBLE THROUGH THE PERIOD.
&&
.FIRE WEATHER...
STRONGEST WIND GUSTS AND LOWEST RELATIVE HUMIDITY VALUES ARE
EXPECTED BETWEEN NOON AND 7PM TODAY OVER WESTERN AND NORTHERN
PORTIONS OF THE FORECAST AREA. RH VALUES RANGING FROM 17 TO 22
PERCENT AND SUSTAINED WINDS AROUND 25 MPH OR SLIGHTLY HIGHER ARE
LIKELY DURING THE AFTERNOON. GFDI VALUES RANGES IN THE MODERATE TO
HIGH CATEGORY PAST NOON TODAY AND MAY BARELY BUMP INTO THE EXTREME
CATEGORY FOR A FEW HOURS BETWEEN 2PM AND 5PM THIS AFTERNOON.
MIXING HEIGHT LOOKS TO BE IN THE 3000 TO 3500 FEET LATE THIS
MORNING AND INTO THE AFTERNOON...WITH A SHORT STINT OF MIXING
HIGHER. REPLACED THE FIRE WEATHER WATCH WITH A RED FLAG WARNING
DUE TO THE VERY LOW RH VALUES...STRONG WINDS...AND FUELS NOT
ENTIRELY GREEN YET.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
ADAIR-ADAMS-AUDUBON-BOONE-CALHOUN-CARROLL-CASS-CERRO GORDO-
CRAWFORD-DALLAS-EMMET-FRANKLIN-GREENE-GUTHRIE-HAMILTON-HANCOCK-
HUMBOLDT-KOSSUTH-PALO ALTO-POCAHONTAS-SAC-WEBSTER-WINNEBAGO-
WORTH-WRIGHT.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...DONAVON
AVIATION...BEERENDS
FIRE WEATHER...PODRAZIK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
142 AM EDT TUE MAY 14 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 351 PM EDT MON MAY 13 2013
TWO WAVES/DISTURBANCES WILL BE THE FOCUS FOR THE FORECAST...WITH
THE FIRST ONE AFFECTING THE AREA TONIGHT AND THE OTHER TOMORROW
AFTERNOON/EVENING.
LATEST WV IMAGERY AND RUC ANALYSIS SHOWS THE AREA UNDER RIDGING
ALOFT AS THE UPPER TROUGH THAT HAD BEEN AFFECTING THE AREA THIS
WEEKEND SHIFTING EAST ACROSS QUEBEC AND AN UPPER RIDGE OVER THE
WESTERN CONUS. THERE IS A DECENT AMOUNT OF MOISTURE ROUNDING THE
RIDGE WITH A 996MB LOW JUST TO THE WEST OF LAKE WINNIPEG. CLOSER TO
HOME...SKIES WERE CLEAR OVER MUCH OF UPPER MICHIGAN THIS
MORNING...BUT INCREASING MID-HIGH CLOUDS ARE SPREADING ACROSS THE
AREA THIS AFTERNOON. BAND OF RAIN IS STARTING TO MOVE INTO WESTERN
LAKE SUPERIOR AT THIS TIME AND IS ASSOCIATED WITH A THIN AREA OF
800-500MB MOISTURE AND 700MB F-GEN.
EXPECT THE BAND TO CONTINUE EAST-SOUTHEAST THIS EVENING AS THE
700MB F-GEN AND BROAD 850-700MB WARM AIR ADVECTION CONTINUE.
BUT...WITH THE 500MB SHORTWAVE AND ASSOCIATED HEIGHT FALLS SHIFTING
EAST THROUGH ONTARIO AND WELL NORTH OF THE AREA ALONG WITH BEING
UNDER THE WRONG AREA OF THE UPPER JET /RIGHT EXIT/ THE BETTER
FORCING ISN/T OVER THE AREA. PLUS...WITH THE DRY AIR IT WILL BE
RUNNING INTO...WONDERING IF THAT WILL LIMIT THE INTENSITY SOME.
WITH AS PERSISTENT AS IT HAS BEEN TODAY...DID BUMP UP POPS A
TOUCH TO GET MORE CHANCE/SCATTERED WORDING IN FOR THIS
EVENING...BUT BASED OFF THE LIMITED RAIN AMOUNTS SEEN UPSTREAM
/TRACE TO A COUPLE HUNDREDTHS/ DIDN/T WANT TO GO MUCH ABOVE THAT. AS
ADDITIONAL 850-700MB MOISTURE SLIDES SOUTHEAST ACROSS THE EASTERN
CWA TONIGHT...WOULD THINK THE PRECIPITATION CHANCES SHOULD INCREASE
SOME OVERNIGHT. THERE IS LITTLE OR NO INSTABILITY WITH THIS PASSING
WAA...AS MID LEVEL LAPSE RATES ARE ONLY AROUND 3-5 C/KM...SO WILL
KEEP THUNDER OUT OF THE FORECAST. WITH THE BETTER CONSISTENCY IN
THIS MOISTURE ARRIVING OVER THE EAST...DID BUMP UP VALUES TO HIGH
CHANCE POPS THERE.
EXPECT TO SEE A BRIEF REPRIEVE ON TUESDAY MORNING BEHIND THE INITIAL
AREA OF WAA TONIGHT. THIS WILL LIKELY PRODUCE SOME BREAKS OR
CLEARING OVER AT LEAST THE WEST HALF OF THE CWA DURING THE MORNING
HOURS BEFORE MID-HIGH CLOUDS STREAM BACK INTO THE AREA. THEN...THE
SHORTWAVE THAT IS CURRENTLY ENTERING THE PACIFIC NORTHWEST WILL BE
MOVING EAST-NORTHEAST ALONG THE US/CANADIAN BORDER AND BE NEAR LAKE
WINNIPEG BY 18Z TUESDAY. WARM AIR ADVECTION WILL AGAIN BE ON THE
INCREASE FROM WEST TO EAST DURING THE AFTERNOON. MOISTURE WILL ALSO
BE LIMITED AS IT MOVES THROUGH THE AREA DURING THE AFTERNOON. BEST
MOISTURE AND CLOSEST PROXIMITY TO THE SHORTWAVE WILL BE OVER THE
NORTHWEST HALF OF THE CWA...SO WILL HAVE HIGHEST POPS THEIR DURING
THE LATTER PART OF THE AFTERNOON. QPF/REFLECTIVITY FROM HIGH
RESOLUTION MODEL RUNS SEEM TO MATCH THIS IDEA AND LEADS TO GREATER
CONFIDENCE.
ELEVATED INSTABILITY IS MARGINAL ALONG/NORTH THE WARM FRONT...WITH
THE BEST INSTABILITY FARTHER SOUTHWEST AND AHEAD OF THE COLD
FRONT. THIS IS LARGELY DUE TO THE MID-LEVEL LAPSE RATES STRUGGLING
TO GET ABOVE 6C/KM. THUS...THUNDER POTENTIAL WILL BE SLIM THROUGH
THE AFTERNOON HOURS. IF ANY ELEVATED THUNDERSTORMS
DEVELOP...WOULDN/T EXPECT THEM TO BE TOO STRONG...AS EFFECTIVE SHEAR
VALUES WILL LIKELY BE BELOW 30KTS THROUGH 00Z ACROSS ALL BUT THE FAR
SOUTHWEST CWA.
AFTER A COOL WEEKEND...TEMPERATURES HAVE STARTED TO REBOUND TODAY
AND EXPECT IT TO CONTINUE ON TUESDAY. THE WARM AIR ADVECTING INTO
THE AREA ON TUESDAY ALONG WITH INCREASING SOUTHERLY FLOW SHOULD LEAD
TO HIGHS IN THE LOWER 70S OVER THE FAR WEST AND A GRADIENT TO THE
50S OVER THE EAST HALF.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 351 PM EDT MON MAY 13 2013
MUCH OF THIS PERIOD WILL BE MARKED BY THE PRESENCE OF A 70KT OR
GREATER 250MB JET OVER UPPER MICHIGAN AND/OR LAKE SUPERIOR...AT
LEAST FROM TUESDAY NIGHT THROUGH SATURDAY MORNING. THIS WILL KEEP
THE AREA IN A RELATIVELY BUSY WEATHER PATTERN...IN BETWEEN THE DOME
OF HOT AIR OVER MUCH OF THE WESTERN HALF OF THE NATION...AND COLDER
AIR RESIDING OVER CANADA.
WE WILL START OUT TUESDAY NIGHT WITH A STACKED 500MB TROUGH-SFC LOW
SET UP JUST NORTH OF CYRL IN WESTERN MANITOBA. A COLD FRONT WILL
EXTEND S FROM THE SFC LOW...THROUGH THE EASTERN THIRD OF MN TO A
SECONDARY SFC LOW/TRIPLE POINT THAT MAY BE DEVELOPING NEAR KDLH.
THE LOCATION OF THE WARM FRONT IS KEY...LIKELY SET UP FROM THE
ARROWHEAD OF MN DOWN AND NEAR THE WI BORDER OF UPPER MI AT 00Z
WEDNESDAY. AS IS TYPICAL...THESE SPLITTING SYSTEMS CAN DEVELOP AND
ROB US OF MOISTURE...AS CONVECTION POPS UP OVER WI. EXPECT
WAA...LIMITED FORCING WILL LIKELY PERSIST...WITH MUCH OF THE BEST
FORCING CLOSER TO THE MAIN SFC/500MB TROUGH ACROSS ONTARIO /WHERE AN
AVERAGE QUARTER OF AN INCH OR MORE OF RAIN IS EXPECTED/. WE LOOK TO
BE IN A PRETTY CAPPED ENVIRONMENT...WITH THE BEST CHANCE FOR ANY
STRONGER SHOWERS OR THUNDERSTORMS OVER SOUTH CENTRAL AND EASTERN
UPPER MI DURING THE LATE EVENING HOURS...AND EVEN THEN LIKELY
ELEVATED ABOVE THE DRY AIR. THE SOUTHERN LOW/COLD FRONT WILL BE OVER
EASTERN UPPER MI/LAKE SUPERIOR BY 09Z WEDNESDAY...AND EAST OF UPPER
MI BY 12Z.
COOLER/DRIER AIR WILL SWEEP IN FOR WEDNESDAY...WITH 850MB TEMPS
FALLING FROM A MAX 14-18C OVERNIGHT TO AN AVERAGE 7-8C DURING THE
DAY WEDNESDAY. PW VALUES FALL TO 0.37 TO 0.44IN...OR 60-70 PERCENT
OF NORMAL...WITH THE LOWEST VALUES AWAY FROM THE KEWEENAW PENINSULA
AND EXTREME S CENTRAL UPPER MI. EXPECT A MORE MODERATED AIRMASS FROM
MUNISING EASTWARD AS MORE MOIST AIR SLIDES IN NEAR THE SHORELINE. A
WORST CASE SCENARIO...WITH THE NAM MIXING UP TO 650-700MB DURING THE
AFTERNOON HOURS...DEW POINTS MIXING DOWN INTO THE UPPER 20S
/F/ WOULD RESULT IN AFTERNOON MIN RH VALUES OF 19-25 PERCENT FROM
JUST E OF IWD TO NORTHERN DELTA COUNTY...WITH GUSTS 25-30KTS. ON A
POSITIVE NOTE...THE LATEST MODEL RUNS ARE NOT QUITE AS STRONG WITH
THE WINDS. WILL NEED TO WAIT AND SEE IF THIS TREND HOLDS. IF
LIMITED...OR NO...PRECIPITATION FALLS TUESDAY NIGHT...FIRE CONCERNS
WILL BE ELEVATED.
BEHIND THE ELONGATED LOW SHIFTING EAST INTO QUEBEC WEDNESDAY
NIGHT...DRY WEATHER WILL REMAIN THROUGH FRIDAY MORNING...WITH COOL
WEST TO NORTHWEST FLOW LINGERING. EXPECT THE RIDGE OF HIGH PRESSURE
TO BE DIRECTLY OVERHEAD ON THURSDAY...WITH LIGHT WINDS AND LAKE
BREEZES EXPECTED.
OUR NEXT WEATHER MAKER WILL BE ORGANIZING ACROSS THE CENTRAL PLAINS
FRIDAY NIGHT THROUGH SATURDAY...BEFORE SHIFTING TOWARD MN AND IA
SATURDAY NIGHT. THE SFC LOW WILL SIT AND SPIN BEFORE FINALLY EXITING
NORTHEASTWARD ACROSS W LAKE SUPERIOR AROUND 06Z MONDAY AND SOUTHERN
ONTARIO DURING THE DAY MONDAY...AS THE 500MB TROUGH/LOW DIVES ACROSS
THE NORTHERN PLAINS SUNDAY INTO SUNDAY NIGHT. ADDED TS CHANCES
SATURDAY THROUGH MONDAY MORNING...BEFORE THE END TO THE BULK OF
MOISTURE. AT THIS POINT IT LOOKS LIKE THERE WILL BE A GOOD CHANCE OF
SOAKING RAIN OVER THE FAR W PORTIONS OF UPPER MI FRIDAY NIGHT
THROUGH SATURDAY...WITH ANOTHER ROUND POSSIBLE LATER SUNDAY INTO
MONDAY AS THE COLD FRONT SWINGS THROUGH.
OTHER THAN SUNDAY TIMING DIFFERENCES BETWEEN THE 12Z RUNS OF THE GFS
AND ECMWF...THE FCST MODELS ARE IN NORMAL TO SLIGHTLY ABOVE NORMAL
AGREEMENT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 139 AM EDT TUE MAY 14 2013
VFR CONDITIONS REMAIN THE RULE AT ALL THREE TAF SITES THROUGH THE
FORECAST PERIOD. CLOUD COVER AND RAIN SHOWERS HAVE ALL BUT EXITED
KIWD AREA AND WILL MOVE OUT OF KCMX BY 8Z...AND KSAW SHORTLY AFTER
THEN. WEAK RIDGING ALOFT BEHIND THE DISTURBANCE WILL REDUCE CLOUD
COVER UNTIL THE APPROACH OF THE NEXT SHORT WAVE BRINGS INCREASING MID
AND HIGH CLOUDS TO THE AREA IN THE LATE AFTERNOON/EVENING. AT THIS
TIME...BETTER MOISTURE AND LOW LEVEL FORCING TO BE FOUND SOUTH OF THE
AREA IN WI...WHILE BETTER DYNAMIC LIFT LOCATED NORTH OF THE
BORDER...LEAVING THE THREE TAF SITES IN BETWEEN. WITH NO STRONG
SIGNAL...WILL JUST MENTION VCSH AT KIWD AND KCMX AND WILL LEAVE OUT
OF KSAW FOR NOW. &&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 351 PM EDT MON MAY 13 2013
HIGH PRESSURE WILL DEPART THE AREA THIS EVENING. THIS WILL LEAD TO
INCREASING SOUTHERLY FLOW TONIGHT INTO TUESDAY AHEAD OF A LOW
PRESSURE SYSTEM MOVING EAST THROUGH SOUTHERN CANADA. AT THIS
POINT...THE INCREASING WARM AIR ABOVE THE SURFACE SHOULD LIMIT GUST
TO 20KTS IN MOST LOCATIONS FOR OVERNIGHT TONIGHT AND TUESDAY.
DISPITE A COUPLE OF SIGNIFICANT SYSTEMS PUSHING THROUGH THE AREA
TUESDAY-TUESDAY NIGHT...AND AGAIN THIS WEEKEND...WINDS ARE CURRENTLY
ANTICIPATED TO REMAIN BELOW 30KTS. IT IS THAT TIME OF YEAR
AGAIN...THERE WILL BE A ROUND OF THUNDERSTORMS POSSIBLE TUESDAY
AFTERNOON OVER WESTERN LAKE SUPERIOR...PUSHING EASTWARD OVERNIGHT
AND ENDING EARLY WEDNESDAY. ANOTHER ROUND OF THUNDERSTORMS WILL BE
POSSIBLE WEST ON SATURDAY/SATURDAY NIGHT...AND ACROSS ALL OF LAKE
SUPERIOR SUNDAY THROUGH MONDAY MORNING.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KF
AVIATION...RJT
MARINE...SRF/KF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
443 AM CDT TUE MAY 14 2013
.FIRE WEATHER...
ISSUED AT 440 AM CDT TUE MAY 14 2013
A RED FLAG WARNING NOW COVERS ALL OF OUR MN COUNTIES FOR THIS
AFTERNOON AND EARLY EVENING. A DRY SURGE OF HEAT WILL OCCUR TODAY
WITH AFTERNOON HUMIDITY VALUES LOWERING TO A FEW PERCENT ABOVE AND
BELOW 20. THE VERY LOW HUMIDITY COUPLED WITH SOUTHWEST TO WEST
WINDS FROM 20 TO 25 MPH ...WITH GUSTS TO 35 MPH... COULD LEAD TO
DANGEROUS WILDFIRE CONDITIONS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 440 AM CDT TUE MAY 14 2013
THERE ARE MANY CONCERNS TODAY AS A LOW PRESSURE SYSTEM AND COLD
FRONT MOVE ACROSS THE FA DURING THE AFTERNOON AND EVENING. A SMALL
COMPLEX OF THUNDERSTORMS DID DEVELOP OVER NORTH DAKOTA OVERNIGHT AS
EXPECTED. THIS AREA OF PRECIPITATION WILL ADVANCE ACROSS NORTHERN
MN THIS MORNING. CONSENSUS FROM THE WRF MODELS WAS LITTLE
(SPRINKLES) OR NOTHING REACHING DOWN INTO CENTRAL MN OTHER THAN
SOME CLOUDS. BY LATE MORNING...THE LOW AND COLD FRONT SHOULD BE
INTO FAR WESTERN AREAS OF MN. SOUTH TO SOUTHWEST WINDS WILL INCREASE
AHEAD OF THE FRONT WHILE RATHER STRONG WEST/NORTHWEST WINDS OCCUR
IN THE WAKE OF THE FRONT. A LOW LEVEL THERMAL RIDGE WILL ADVANCE
NORTHEAST FROM THE CENTRAL PLAINS AND REACH INTO THE TWIN CITIES
BY LATE IN THE AFTERNOON. THE SHORT TERM MODELS REMAIN CONSISTENT
ON 23-26 DEG C AIR AT 850MB FROM THE TWIN CITIES ON SOUTHWEST INTO
NORTHERN IA RESPECTIVELY. HIGHS RECENTLY TO OUR WEST AND NORTHWEST
(CANADA) HAVE BEEN RUNNING REAL CLOSE TO 20 DEGREES ABOVE THESE
CONVERTED VALUES. THIS WOULD YIELD HIGHS FROM 93 TO 99 DEGREES.
AS A RESULT... OUR CURRENT FORECAST WAS RAISED A FEW DEGREES...
ESPECIALLY ACROSS SOUTH CENTRAL MN... WHERE THE RAP SOUNDINGS WERE
SHOWING HIGHS OF 100-103. THIS ALSO RESULTED IN A RECORD HIGH BEING
FORECAST FOR THE TWIN CITIES.
THE HEAT TODAY HAS LEAD TO THE ISSUANCE OF A HEAT ADVISORY FROM
THE TWIN CITIES ON SOUTH AND SOUTHWEST TO ALBERT LEA AND REDWOOD
FALLS. THIS IS A DRY HEAT BEING ACCOMPANIED BY 20 TO 25 MPH WINDS
DURING THE AFTERNOON... WHICH MAY LEAD TO DEHYDRATION ISSUES FOR
THOSE WORKING OUTSIDE. ANOTHER IMPORTANT ISSUE IS THAT THE TWIN
CITIES HAS ONLY BEEN IN THE 80S ONCE SO FAR THIS YEAR WITH 81
DEGREES ON APRIL 28TH. THIS BURST OF HEAT MAY LEAD TO HEALTH
ISSUES.
ANOTHER CONCERN TODAY IS THE POTENTIAL FOR WIND ADVISORY CRITERIA
BEING MET IN THE NORTHWEST CWA IN THE MID TO LATE AFTERNOON HOURS.
THE RAP LOW LEVEL WINDS IN THE 200-300 FOOT RANGE ARE FORECAST IN
THE UPPER 20 KNOT RANGE. THIS IS THE HIGHEST OF ALL THE GUIDANCE.
THE NAM WINDS WERE MORE IN THE 23-24 KNOT RANGE WHICH BLENDED WELL
WITH THE LAMP GUIDANCE. CRITERIA FOR A WIND ADVISORY HAS A BETTER
CHANCE OF BEGIN MET OVER NORTH DAKOTA. AT THIS POINT WE HELD OFF
ON ISSUING AN ADVISORY.
FINALLY...ALTHOUGH A STRONG CAP EXISTS IN THE 700-750MB RANGE
TODAY...THERE REMAINS SOME POTENTIAL FOR CONVECTION TO BREACH THE
CAP AND DEVELOP DURING THE LATE AFTERNOON/EVENING ALONG THE
FRONT... MAINLY TO THE EAST AND SOUTH OF THE TWIN CITIES. WE KEPT
THE SMALL CHANCES FOR THUNDERSTORMS AS IS. OUR LOCAL WRF WAS THE
MOST AGGRESSIVE WITH ACTIVITY DEVELOPING FROM JUST SOUTH OF THE
TWIN CITIES TO OMAHA AROUND 21Z...WHILE THE NMM WRF HAS SOME
STORMS JUST EAST OF US. MOST OF THE SOLUTIONS SHOW A HIGHER CHANCE
FOR STORMS OVER IA TONIGHT AS WELL AS IN NORTHEAST WI. GIVEN THE
SHEAR FORECAST...STORMS THAT DO DEVELOP COULD BECOME SEVERE WITH
LARGE HAIL AND DAMAGING WINDS... ESPECIALLY WITH THE INVERTED V
SOUNDING. NAM DOWNDRAFT CAPE VALUES ARE ON THE ORDER OF 1000 J/KG
OVER WEST CENTRAL WI AND SE MN LATE THIS AFTERNOON AND EVENING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 415 AM CDT TUE MAY 14 2013
WEDNESDAY THROUGH MONDAY...QUIET AND SEASONABLE WEATHER WILL GIVE
WAY TO A WETTER PATTERN AT THE END OF THE PERIOD. SEVERE WEATHER IS
ALSO POSSIBLE FOR THE WEEKEND. EARLY MORNING NORTHERN HEMISPHERIC IR
IMAGERY TOGETHER WITH THE ECMWF 250MB HEIGHTS AND WINDS IDENTIFIED
ZONAL FLOW ACROSS THE WESTERN CONUS...WITH A LOW AMPLITUDE PATTERN
ACROSS THE PACIFIC. FOR WEDNESDAY AND THURSDAY THIS ZONAL FLOW WILL
SET UP ACROSS INTERNATIONAL BORDER...WITH NEGATIVE VORTICITY
ADVECTION AND WEAK SUBSIDENCE ACROSS THE UPPER MIDWEST. THIS WILL
RESULT IN TWO DRY DAYS WITH LIGHT WINDS AND TEMPERATURES 5 TO 10
DEGREES ABOVE THE SEASONAL AVERAGE FOR MID MAY.
BY THURSDAY NIGHT THE AFOREMENTIONED LOW AMPLITUDE JET ACROSS THE
PACIFIC WILL BEGIN TO DIG ACROSS THE WESTERN US...WITH A BROAD AREA
OF LEE SIDE TROUGHING ALONG THE EASTERN SPINE OF THE ROCKIES. THIS
WILL INDUCE SOUTHERLY FLOW WITH GULF MOISTURE TRANSPORT ACROSS THE
CENTRAL CONUS...AND GRADUALLY BUILD AN UPPER LEVEL RIDGE THURSDAY
NIGHT INTO FRIDAY. MEANWHILE THE COLD FRONT THAT WILL HAVE PASSED
THROUGH THE AREA ON TUESDAY AND STALL OUT ACROSS SOUTHERN IOWA WILL
LIFT NORTHWARD AS A WARM FRONT. LOW LEVEL THETA_E ADVECTION AS SEEN
IN THE H925-850 LAYER SHOULD PROMOTE THUNDERSTORM DEVELOPMENT ALONG
THE WARM FRONT...WHILE THE UPPER LEVEL ANTICYCLONIC FLOW ALOFT
ALLOWS EVACUATES THE OUTFLOW FROM THESES STORMS AND ALLOWS THEM TO
PERSIST. DIFFICULT TO QUANTIFY THE CONVECTIVE POTENTIAL SINCE THE
LOW LEVEL MOISTURE HAS BEEN UNRELIABLE LATELY. HOWEVER...THE
SYNOPTIC SETUP WITH GULF MOISTURE ADVECTION INCREASES CONFIDENCE
THAT THESE MOISTURE DEPENDENT VARIABLES...A.K.A. CAPE...ARE
REASONABLY REPRESENTED. DEEP LAYER SHEAR PROFILES VARY DEPENDING ON
THE TIMING AND PLACEMENT OF THE WARM FRONT...BUT BOTH THE 14.12 GFS
AND ECMWF ARE IN GOOD AGREEMENT AND LIFT THE FRONT THROUGH THE CWA
ON FRIDAY. MEANWHILE THE UPPER LEVEL JET WILL CONTINUE TO CARVE OUT
A TROUGH OVER THE FOUR CORNERS REGION. THE GFS...GEM...AND ECMWF ALL
DEVELOP A SURFACE LOW AND TRACK IT ACROSS THE UPPER MIDWEST FOR THE
WEEKEND...BRINGING CONTINUED CHANCES FOR PRECIP. THE RUN TOTAL
PRECIP FROM THE GFS AND ECMWF INDICATE THAT OVER 3 INCHES OF RAIN
ARE POSSIBLE. WITH THIS PROLONGED PERIOD OF PRECIP. IN
SUMMATION...EXPECT AN MCS TO DEVELOP THURSDAY NIGHT AND MOVE ACROSS
THE REGION FRIDAY AS THE WARM FRONT LIFTS NORTHWARD. THEN WILL SEE
CONTINUES CHANCES FOR THUNDERSTORMS SATURDAY AND SUNDAY AS THE UPPER
LEVEL DYNAMICS BECOME MORE FAVORABLE FOR ASCENT. SEVERE WEATHER
REMAINS POSSIBLE...BUT CONFIDENCE IN THE EXACT PLACEMENT OF THE
MESOSCALE FEATURES IS LOW AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1201 AM CDT TUE MAY 14 2013
VFR CONDITIONS THROUGH THE TAF PERIOD WITH JUST SOME HIGH CLOUDS
POSSIBLE. WIND WILL BE THE BIGGEST AVIATION WEATHER CONCERN
TOMORROW. WE SHOULD SEE PLENTY OF GUSTS BETWEEN 20-30 KTS IN MN BY
THE LATE MORNING OUT OF THE S-SW. WIND WILL FOLLOW IN WI 2-3 HOURS
LATER. EXPECT GUSTS NEAR OR OVER 30 KTS IN MANY LOCATIONS BY THE
AFTERNOON. NO REAL CONCERN WITH SHOWERS AND THUNDERSTORMS OUTSIDE
OF FAR EASTERN MN AND WESTERN WI TOMORROW AFTERNOON AND EVENING.
INCLUDE VCTS IN THE FORECAST FOR KEAU...BUT CONFIDENCE IN STORM
DEVELOPMENT AND COVERAGE IS STILL A BIG QUESTION MARK.
KMSP...
NO CONCERNS WITH THE CEILINGS OR VISIBILITY OVER THE NEXT 30
HOURS. THERE IS A SLIM CHANCE FOR A SHOWER OR THUNDERSTORM
TOMORROW AFTERNOON...BUT EVEN IF WE WERE CONFIDENT IN
DEVELOPMENT...THE COVERAGE LOOKS BETTER TO THE EAST AND IT SHOULD
EVEN BE ISOLATED WHERE IT DOES OCCUR. WINDS WILL BE STRONG OUT OF
THE S-SW BY THE AFTERNOON AND SLOWLY VEER AND REMAIN STRONG
THROUGH THE EVENING PUSH.
/OUTLOOK FOR KMSP/
WED...VFR. NW WINDS 10 KTS.
THU...VFR. WINDS W 5 KTS.
FRI...MVFR POSSIBLE WITH CHC -TSRA. WINDS SE 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...RED FLAG WARNING FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
MNZ041>045-047>070-073>078-082>085-091>093.
HEAT ADVISORY FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
MNZ059>063-065>070-073>077-082>085-091>093.
WI...NONE.
&&
$$
FIRE WEATHER...RAH
SHORT TERM...RAH
LONG TERM...JRB
AVIATION...CLF
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
355 AM CDT TUE MAY 14 2013
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 355 AM CDT TUE MAY 14 2013
FORECAST CHALLENGES INCLUDE SHOWERS AND THUNDERSTORMS THIS
MORNING...FOLLOWED BY STRONG WINDS AND CRITICAL FIRE WEATHER
CONDITIONS THIS AFTERNOON. GFS/NAM/ECMWF/GEM ARE IN GOOD
AGREEMENT...BUT WILL USE LATEST HRRR FOR PRECIPITATION TRENDS
THROUGH 18 UTC. THEREAFTER...A BLENDED SOLUTION SHOULD SUFFICE.
08 UTC WATER VAPOR LOOP SHOWS A STRONG...YET PROGRESSIVE SHORT
WAVE MOVING ALONG THE CANADIAN BORDER AND INTO NORTHEAST MT. A
CLUSTER OF SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ACROSS CENTRAL
ND IN AN AREA OF WEAK ELEVATED INSTABILITY AND INCREASED
DIVERGENCE ALOFT AHEAD OF A SURFACE COLD FRONT WHICH STRETCHES
FROM NEAR WILLISTON TO MILES CITY MT. LATEST HRRR SHOWS THIS
CONVECTIVE ACTIVITY MOVING EASTWARD THROUGH THE EARLY MORNING AND
INTO THE MN ARROWHEAD AFTER 15 UTC. INCREASED POPS FROM 60 TO 80
PERCENT ACROSS THE NORTHERN HALF OF THE FORECAST AREA THIS MORNING
WHERE A QUICK QUARTER INCH OF RAIN IS POSSIBLE... ESPECIALLY FOR
THOSE AREAS THAT SEE THUNDERSTORMS.
THE COLD FRONT IS FORECAST TO REACH THE VALLEY FLOOR BY 18 UTC.
WITH STRONG LOW-MID LEVEL COLD AIR ADVECTION IN ITS WAKE...AN
ADIABATIC BOUNDARY LAYER TO 750 HPA AND 30 TO 40 KTS TO MIX
DOWN...EXPECT WINDY CONDITIONS TO DEVELOP FROM WEST TO EAST
THROUGH THE AFTERNOON. WEST WINDS FROM 30 TO 40 MPH WITH GUSTS UP
TO 50 MPH ACROSS THE HIGHER TERRAIN OF EASTERN ND NECESSITATES A
WIND ADVISORY FROM 17 TO 02 UTC FOR ALL AREAS EXPECT THE FAR
EASTERN COUNTIES. WILL CANCEL THE HIGH WIND WATCH AS WINDS ARE NOT
EXPECTED TO REACH CRITERIA. HIGH TEMPERATURES TODAY STILL
EXPECTED TO CLIMB INTO THE MID 70S TO MID 80S BEFORE FRONTAL
PASSAGE AND WHEN COMBINED WITH STRONG WINDS AND LOW RH WILL CREATE
DANGEROUS FIRE WEATHER CONDITIONS. SEE DISCUSSION BELOW FOR MORE
DETAIL.
THIS AFTERNOON THROUGH WEDNESDAY WILL BE DRY AS SURFACE HIGH
PRESSURE BUILDS ACROSS THE REGION. WINDS WILL DIMINISH SOMEWHAT
AFTER SUNSET...BUT REMAIN ELEVATED FROM THE WEST-NORTHWEST TONIGHT
THROUGH WEDNESDAY. TOMORROW WILL BE A BIT COOLER WITH AFTERNOON
HIGHS IN THE 70S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 355 AM CDT TUE MAY 14 2013
WEDNESDAY NIGHT THROUGH MOST OF THURSDAY WILL BE DRY...BUT EXPECT
PRECIPITATION CHANCES TO INCREASE THURSDAY NIGHT AHEAD OF THE NEXT
PACIFIC TROUGH. GFS/ECMWF BOTH SHOW A WIDE SWATH OF SHOWERS AND
STORMS MOVING INTO EASTERN ND BY 12 UTC FRIDAY. INCREASED POPS
INTO THE HIGH CHANCE CATEGORY...BUT IF MODEL TRENDS CONTINUE...
WILL NEED TO INCREASE FURTHER. DON/T EXPECT MUCH TEMPERATURE
CHANGE FROM WEDNESDAY WITH THURSDAY/S HIGHS IN THE 70S.
00Z ECMWF/GFS WERE IN GOOD AGREEMENT WITH OVERALL PATTERN FRI-MON
IN SHOWING A LARGE 500 MB TROUGH OVER THE ROCKIES LIFTING
NORTHEAST INTO THE NRN PLAINS AND EVENTUAL 500 MB LOW FORMATION IN
MINNESOTA. THIS LEADS TO AN EXTENDED PERIOD OF PRECIPITATION
CHANCES THRU THE PD. SHOWWALTERS FROM THE MODELS PROG INDICATE
SOME THUNDERSTORM POTENTIAL FRI-SUN THEN MOSTLY SHOWERS ON MONDAY.
OVER THE 4 DAY PERIOD...SOME HEAVY RAINFALL TOTALS ARE POSSIBLE
SOMEWHERE IN OUR REGION AS PWATS INCREASE TO 1.50 INCHES OVER SE
ND INTO NRN MN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1154 PM CDT MON MAY 13 2013
VFR CONDITIONS WILL CONTINUE THROUGHOUT THE PERIOD. A FEW SHOWERS
OR THUNDERSTORMS ARE POSSIBLE 09Z AND AFTER AROUND KDVL AND
FURTHER EAST LATER ON. WINDS WILL PICK UP OUT OF THE WEST AFTER
18Z WITH 20 TO 30 KTS AND GUSTS ABOVE 35 KTS. WINDS WILL DIMINISH
AFTER 01Z WEDNESDAY.
&&
.FIRE WEATHER...
ISSUED AT 355 AM CDT TUE MAY 14 2013
WILL ISSUE RED FLAG WARNING FOR ALL OF ERN ND INTO MUCH OF NW/WCNTRL
MN (EXCEPT LAKE OF THE WOODS AND NORTH BELTRAMI REGIONS) FOR 17Z TUE
TO 02Z WED. EVENING DISCUSSION WITH MN FIRE AGENCY INDICATES FUELS
ARE DRY AND PRIME. WILDFIRE ONGOING NEAR GRYGLA IN SOUTHEASTERN
MARSHALL COUNTY. FUELS REMAIN DRY IN ERN ND AS WELL...THOUGH PARTS
OF NE ND AND FAR NW MN WILL SEE SOME RAINFALL THIS MORNING. THE
EXTENT OF RAINFALL THIS MORNING IS STILL UNCERTAIN. AIDING IN FIRE
POTENTIAL IS STRONG WESTERLY WINDS THAT WILL SPREAD EAST BEHIND
THE COLD FRONT INTO ERN ND MIDDAY AND INTO NW/WCNTRL MN THIS AFTN
WITH GUSTS 40-50 MPH IN ERN ND AND 35 TO 45 MPH IN THE PRAIRIE
REGIONS OF NW/WCNTRL MN. THUS RED FLAG WARNING ISSUED. NOW HOURLY
TRENDS OF RELATIVE HUMIDITY WILL BE A CHALLENGE AND VERY DIFFICULT
TO FORECAST FOR DUE TO IMPACTS OF ANY MORNING PRECIP AND LOCATION.
THUS COULD HAVE WIDE VARIATIONS THIS MORNING-MIDDAY UNTIL THE
FRONT AND WESTERLY WINDS ARRIVE.
&&
.HYDROLOGY...
ISSUED AT 1258 PM CDT MON MAY 13 2013
RIVER FLOOD WARNINGS CONTINUE ON THE RED RIVER AT OSLO...DRAYTON
AND PEMBINA. RIVER STAGES AT DRAYTON AND PEMBINA ARE CONTINUING A
SLOW RECESSION...WITH STAGES AT OSLO FALLING MORE RAPIDLY.
OTHERWISE...MOST OTHER POINTS ON THE MAINSTEM RED AND ON THE ND/MN
TRIBUTARIES SHOW RECEDING OR NEARLY STEADY LEVELS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...RED FLAG WARNING FROM NOON TODAY TO 9 PM CDT THIS EVENING FOR
NDZ006>008-014>016-024-026>030-038-039-049-052>054.
WIND ADVISORY FROM NOON TODAY TO 9 PM CDT THIS EVENING FOR
NDZ006>008-014>016-024-026>030-038-039-049-052>054.
MN...RED FLAG WARNING FROM NOON TODAY TO 9 PM CDT THIS EVENING FOR
MNZ001>005-007-008-013>017-022>024-027>032-040.
WIND ADVISORY FROM NOON TODAY TO 9 PM CDT THIS EVENING FOR
MNZ001>005-007-008-013>016-022-023-027>031-040.
&&
$$
SHORT TERM...ROGERS
LONG TERM...ROGERS/RIDDLE
AVIATION...JR
FIRE WEATHER...RIDDLE
HYDROLOGY...SPEICHER
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
343 AM CDT TUE MAY 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CDT TUE MAY 14 2013
MAIN CHALLENGE FOR TODAY WILL BE WINDS/HUMIDITY LEVELS/ASSOCIATED
FIRE WEATHER CONCERNS IN MIXY ENVIRONMENT AHEAD OF AND BEHIND COOL
FRONT WHICH WILL PUSH SOUTHEAST ACROSS THE REGION THROUGH THE DAY.
LOW LEVEL TEMPERATURES AHEAD OF THE FRONT EASILY SUPPORTIVE OF MID
90S ACROSS MUCH OF NORTHWEST IOWA THIS AFTERNOON...WITH SOME MODELS
SHOWING POTENTIAL FOR HIGHS CLOSER TO OR JUST ABOVE THE CENTURY MARK.
WITH THE STRONG MIXING COMES LIKELIHOOD OF MIXING DRIER AIR ALOFT TO
THE SURFACE. MODELS HAVE BEEN HAVING DIFFICULTY CAPTURING THE DIURNAL
DRYING TREND WITH AFTERNOON MIXING...HANGING ONTO SHALLOW MOISTURE OR
MIXING BOUNDARY LAYER MOISTURE UPWARD RATHER THAN BRINGING DRIER AIR
TO SURFACE AS DEEPER MIXING COMMENCES. RUC SEEMS TO HANDLE IT BETTER
THAN NAM/GFS...AND MORE CLOSELY FOLLOWED THAT IDEA THROUGH THE LATE
MORNING/AFTERNOON...THOUGH NOT QUITE AS DRY AS RUC INDICATES AT THIS
POINT GIVEN EXTREME DISPARITY FROM OTHER MODELS /AS MUCH AS 10-15F
DRIER THAN MOST OTHER GUIDANCE FOR 21Z/. DRIEST AIR SHOULD BE OVER
FAR SOUTHEAST AND WESTERN PARTS OF THE FORECAST AREA DURING PEAK
HEATING...WITH SLIGHT MOISTURE POOLING IN SOMEWHAT LESS MIXY AREA
RIGHT ALONG THE FRONT...FORECAST TO BE JUST EAST OF KYKN-KFSD-KMML
LINE AT 21Z. ALL THIS LEADS TO MINIMUM HUMIDITY LEVELS OF 15-25
PERCENT THIS AFTERNOON... AND THIS ALONG WITH WINDS GUSTING IN THE
25-30KT RANGE STILL SUPPORTIVE OF RED FLAG WARNING WHICH WAS ISSUED
ON THE DAY SHIFT YESTERDAY.
COLD FRONT SETTLES SOUTH OF THE AREA TONIGHT...WITH COOLING
TEMPERATURES AND DYING WINDS OVERNIGHT. LOWS LOOK TO DROP INTO THE
UPPER 40S NORTHWEST...TO MID 50S THROUGH THE LOWER MISSOURI RIVER
VALLEY INTO NORTHWESTERN IOWA.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 343 AM CDT TUE MAY 14 2013
SURFACE HIGH PRESSURE BUILDS SOUTHWARD INTO THE REGION ON WEDNESDAY
AND WEDNESDAY NIGHT...PROVIDING FOR PLEASANT CONDITIONS WITH
TEMPERATURES CLOSE TO NORMAL FOR THIS TIME OF YEAR. THIS WILL PLAY
OUT TO HIGHS IN THE MID AND UPPER 70S...WITH LOWS EARLY ON THURSDAY
IN THE UPPER 40S TO LOWER 50S.
THE HIGH MOVES EASTWARD ON THURSDAY WITH A SOUTHERLY FLOW RETURNING
TO OUR AREA ON THE BACKSIDE OF THE HIGH. THINK MOST OF THE DAY WILL
REMAIN DRY WITH WARMING TEMPERATURES...INTO THE UPPER 70S TO AROUND
80 FOR AFTERNOON HIGHS. CANNOT RULE OUT SOME THUNDERSTORM
DEVELOPMENT IN OUR SOUTHWEST LATER IN THE AFTERNOON...WITH A BETTER
CHANCE ON THURSDAY NIGHT AS A WARM FRONT BEGINS TO LIFT THROUGH
NEBRASKA AND 850 MB CONVERGENCE IS ENHANCED AS A LOW LEVEL JET
DEVELOPS THROUGH THE REGION. DOES APPEAR TO BE ENOUGH ELEVATED
CAPE...500 TO 1000 J/KG...AND EFFECTIVE SHEAR OF AROUND 30 KTS IN
THE EVENING THAT CANNOT RULE OUT A COUPLE OF SEVERE STORMS WITH
LARGE HAIL.
A MESSY PATTERN CONTINUES THROUGH THE EXTENDED...FRIDAY INTO MONDAY
OF NEXT WEEK...WITH PERIODIC CHANCES OF CONVECTION THROUGH THE
PERIOD WITH A BOUNDARY MEANDERING AROUND THE AREA AND A SERIES OF
SUBTLE WAVES TRACKING ACROSS THE REGION. HARD TO TIME THIS
CONVECTION DEPENDENT ON WHERE SYNOPTIC/MESOSCALE FEATURES SET
UP...BUT WITH INCREASING LOW LEVEL MOISTURE AND INSTABILITY ACROSS
THE REGION THROUGH THE WEEKEND THERE IS FAIRLY HIGH CONFIDENCE THAT
CONVECTION WILL OCCUR. CONVECTIVE PARAMETERS WOULD ALSO SUGGEST THAT
SEVERE STORMS WILL BE POSSIBLE FOR THOSE DAYS. AN UPPER LEVEL TROUGH
FINALLY SWINGS OUT OF THE WESTERN U.S. ON SUNDAY AND
MONDAY...KEEPING A CHANCE OF CONVECTION ACROSS THE REGION...AS WELL
AS BRINGING A COOLING TREND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1045 PM CDT MON MAY 13 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. LIGHT WESTERLY
FLOW SHOULD GRADUALLY BECOME MORE SOUTHERLY THROUGH THE OVERNIGHT.
GUSTY CONDITIONS WILL RETURN 14-15 Z WITH WINDS SHIFTING TO THE
NORTHWEST THROUGHOUT THE DAY TUESDAY AS A COLD FRONT MOVES
THROUGH. THE GUSTY CONDITIONS SHOULD SUBSIDE WITH SUNSET.
&&
.FIRE WEATHER...
ISSUED AT 343 AM CDT TUE MAY 14 2013
RED FLAG WARNING STILL LOOKS WARRANTED FOR THE AFTERNOON AND EARLY
EVENING. GUSTY SOUTHWEST WINDS OF 25 TO 35 MPH AHEAD OF COOL FRONT
WILL SWITCH TO NORTHWEST BEHIND THE FRONT AND REMAIN AS STRONG. ALONG
WITH THE GUSTY WINDS WILL BE DRY RELATIVE HUMIDITY LEVELS IN THE 15
TO 25 PERCENT RANGE...AS DRY AND UNSEASONABLY WARM AIR ALOFT MIXES TO
THE SURFACE. AREAS RIGHT ALONG THE FRONT MAY NOT SEE AS SUSTAINED A
PERIOD OF RED FLAG CRITERIA DUE TO MOISTURE POOLING AND LIGHTER/LESS
GUSTY WINDS WITHIN THE FRONTAL ZONE...BUT SHOULD STILL REACH CRITERIA
AT TIMES. RECENT GREENING OF COOL SEASON GRASSES MAY SLOW FIRE STARTS
ACROSS THE AREA...BUT ANY FIRES THAT DO IGNITE WILL SPREAD VERY
QUICKLY IN THE LINGERING DORMANT TALL GRASSES.
SOME MODELS ALSO INDICATE POTENTIAL FOR EVEN WARMER/DRIER AIR MIXING
TO THE SURFACE AHEAD OF THE FRONT...MAINLY IN NORTHWEST IOWA THIS
AFTERNOON...SO THIS WILL BE WATCHED CLOSELY THROUGHOUT THE DAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...RED FLAG WARNING FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
SDZ255>258.
MN...RED FLAG WARNING FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
MNZ900.
IA...RED FLAG WARNING FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
IAZ300-301.
NE...RED FLAG WARNING FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
NEZ249.
&&
$$
SHORT TERM...JH/JM
LONG TERM...JM
AVIATION...
FIRE WEATHER...JH
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND WEDNESDAY
ISSUED AT 436 AM CDT TUE MAY 14 2013
FORECAST CONCERNS ON TEMPERATURES TODAY AND CHANCE FOR
THUNDERSTORMS LATER THIS AFTERNOON AND THIS EVENING. HAVE TRENDED
TOWARDS GEM/NAM FOR GUIDANCE ON THIS PACKAGE. ECMWF NOW TRENDING
TOWARDS NAM WITH BETTER CHANCE FOR PCPN A BIT FURTHER SOUTH INTO
CENTRAL WI CLOSER TO WARM FRONT POSITION.
LAST EVENING SOUNDINGS SHOWS WHAT THE ISSUE WITH THIS
FORECAST...THAT BEING TOO DRY. AREA OF HIGH BASED SHOWERS WENT
THROUGH LAST NIGHT AROUND MIDNIGHT ASSOCIATED WITH STRONG WAA/850
WARM FRONT. NOTHING MORE THAN SPRINKLES SEEN. MID CLOUDINESS NOW
EXITING EASTERN WI.
FOCUS ON FAST MOVING SHORT WAVE ALONG CANADIAN BORDER AND FRONTAL
SYSTEM NOW MOVING THROUGH NORTHERN PLAINS. BY MID AFTERNOON...WARM FRONT
TO LIFT NORTH INTO SOUTHWEST WI. RATHER WARM AIR MASS TO PUSH INTO
STATE TODAY WITH 850 TEMPS INTO THE 20S OVER CENTRAL WI. WITH STEEP
MID-LEVEL LAPSE RATES BETWEEN 8 AND 9 C/KM....AND WARM
FRONT...WILL CONTINUE TO CARRY SMALL/ISOLD CHANCE FOR
THUNDERSTORMS. MODEL SOUNDINGS SUGGEST STRONG CIN THROUGH THE DAY
GIVEN DRY AIRMASS BELOW 600MB. SOUNDINGS ALSO SHOW CAPE HIGH
BASED...MAINLY ABOVE 600MB. THIS TO LEAD TO HIGH BASED
THUNDERSTORM THREAT...WHICH IF STORMS DO DEVELOP WOULD LIKELY LEAD TO
GUSTY WINDS...POSSIBLY HAIL. COLD FRONT TO PUSH THROUGH STATE BY
MIDNIGHT LEADING TO DRY FORECAST FOR REST OF NIGHT AND WEDNESDAY.
ON WEDNESDAY...GUSTY NORTHWEST WINDS BEHIND FRONT AND LOW
HUMIDITIES WITH MIXING TO 5K FEET OR HIGHER MAY LEAD TO INCREASED
FIRE DANGER.
TEMPERATURES TO BE WELL ABOVE NORM TODAY...DROPPING CLOSER TO
NORMS ON WEDNESDAY. FEW MODELS...INCLUDING HRRR SUGGEST 90 INTO
SOUTHWEST WI. HAVE BUMPED TEMPS UP SLIGHTLY THROUGHOUT CWA.
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY
ISSUED AT 436 AM CDT TUE MAY 14 2013
SURFACE HIGH PRESSURE MOVING ACROSS THE REGION AHEAD OF AN UPPER
LEVEL RIDGE SHOULD KEEP THE EARLY PART OF THE LONG TERM FORECAST
DRY. THE 00Z NAM AND 00Z GFS GENERATED SOME QPF DURING THE DAY ON
THURSDAY...BUT SINCE THE 00Z ECMWF...PREVIOUS FORECAST AND
SURROUNDING GRIDS WERE DRY...A DRY FORECAST APPEARED TO BE THE WAY
TO GO.
A SHORT WAVE AND WARM ADVECTION AHEAD OF A SURFACE TROUGH
APPROACHING FROM THE PLAINS WILL BRING A CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE AREA STARTING ON FRIDAY. VARIOUS SHORT WAVES
AHEAD OF THE MAIN UPPER TROUGH AND A SURFACE FRONTAL
BOUNDARY...COMBINED WITH A FEED OF GULF MOISTURE AHEAD OF A
DEVELOPING SURFACE LOW WILL KEEP AT LEAST A CHANCE OF SHOWERS AND
THUNDERSTORMS THROUGH THE END OF THE FORECAST PERIOD.
CLOUDS AND PRECIPITATION WILL KEEP TEMPERATURES FROM WARMING TOO
MUCH ABOVE NORMAL DURING THE DAYTIME...BUT THE SAME FACTORS SHOULD
KEEP TEMPERATURES WELL ABOVE NORMAL AT NIGHT.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1034 PM CDT MON MAY 13 2013
MID LEVEL CLOUDS WITH ISOLATED SHOWERS WILL LINGER
EASTERN WISCONSIN OVERNIGHT. LLWS CONDITIONS TO PERSIST THROUGH
15Z TUESDAY. VFR CONDITIONS WILL CONTINUE TUESDAY...WITH PERHAPS A
CHANCE OF A MVFR CIGS WITH SHOWERS OR A THUNDERSTORM TUESDAY NIGHT
WITH THE PASSAGE OF A COLD FRONT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....TE
LONG TERM......MG
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
932 AM MDT TUE MAY 14 2013
.UPDATE...OVERALL JUST MINOR ADJUSTMENTS TO THE GRIDS TODAY. MDLS
INDICATE MORE OF AN INVERTED PROFILE WITH THE SOUNDINGS THIS
AFTERNOON AS THE LOW LEVEL MOISTURE MIXES OUT...SO LIGHT RAINFALL
AND GUSTY OUTFLOW WINDS THE MAIN PRODUCTS OF THESE STORMS. ISOLD
COVERAGE EAST OF I-25 SHOULD NOT BECOME A REALITY UNTIL THIS
EVENING. HRRR INDICATES THE BEST TSTM COVERAGE THIS AFTN WILL BE
ALONG THE PALMER DIVIDE. FCST CAPES AROUND 500 J/KG...WITH
TEMPERATURES LIKELY EQUALING OR EXCEEDING OUR RECORD HIGH IN
DENVER FOR THIS DATE. WEAK FRONTAL BOUNDARY SHOULD BACK ITS WAY
INTO THE CWFA THIS EVENING.
&&
.AVIATION...NO BIG ADJUSTMENTS PLANNED AT THIS TIME. GUSTY OUTFLOW
WINDS THE PRIMARY ISSUE WITH THE TSTMS THIS AFTN SO ADDED TEMPO
PERIOD IN THE 23-01Z TIME FRAME TO REFLECT THIS...OTHERWISE THE
REST OF THE TAF LOOKS ON TRACK.
&&
.PREV DISCUSSION... /ISSUED 356 AM MDT TUE MAY 14 2013/
SHORT TERM...A FLAT UPPER LEVEL RIDGE WILL BE OVER THE AREA THRU
TONIGHT WITH WEAK FLOW ALOFT. AT THE SURFACE THERE WILL BE A WK
BNDRY MOVING ACROSS NERN CO BY MIDDAY WITH LOW LVL WINDS BECOMING
NNE BY MIDDAY AND THEN MORE ELY BY LATE AFTN. OVERALL INSTABILITY
IS NOT THAT GREAT BASED ON CURRENT SOUNDINGS WITH CAPES UNDER 500
J/KG. HOWEVER WITH SOME INCREASE IN MID LEVEL MOISTURE WILL SEE
SOME HIGH BASED STORMS OVER THE HIGHER TERRAIN THIS AFTN. OVER
NERN CO THE NAM SHOWS SOME ISOLD TO WDLY SCT CONVECTION BY 21Z
WHILE GFS KEEPS ALL OF THE ACTIVITY IN THE FOOTHILLS AND MTNS THRU
00Z. FOR NOW WILL JUST KEEP SOME LOW POPS ALONG THE FRONT RANGE AND
ACROSS THE PALMER DIVIDE IN THE 21Z-00Z TIME PERIOD. AS FOR HIGHS
WK BNDRY MOVING ACROSS NERN CO DOES NOT HAVE ANY COOL AIR SO WITH
LITTLE CHANGE TO 850-700 MB TEMPS HIGHS SHOULD BE SIMILAR TO MON.
RECORD HIGH AT DENVER IS 87 WHICH COULD BE TIED OR BKN.
FOR TONIGHT THE NAM AND GFS INCREASE THE LOW LEVEL MOISTURE
ACROSS NERN CO THIS EVENING AS A COOL FNT MOVES INTO THE AREA.
THE GFS BLOWS UP CONVECTION IN THE 00Z-06Z TIMEFRAME OVER NERN CO
WHILE THE NAM HAS FAR LESS ACTIVITY AS WELL AS THE ECMWF. FOR NOW
WILL TREND MORE TOWARDS THE NAM AND ECMWF AND KEEP A SLIGHT CHC
ACROSS THE PLAINS.
LONG TERM...GENERALLY SPEAKING...THE NEXT WEEK OF WEATHER WILL
PRIMARILY BE ISOLATED-SCATTERED AFTERNOON CONVECTION OVER THE
MOUNTAINS AND A SLIGHT CHANCE OF AFTERNOON OR EVENING SHOWERS ON
THE PLAINS. WHEN LOOKING AT THE DETAILS...WEDNESDAY AFTERNOON WILL
FEATURE A SPLIT IN THE UPPER FLOW...THURSDAY WILL HAVE INCREASING
SOUTHWEST FLOW ALOFT...WHILE FRIDAY NIGHT AND SATURDAY FEATURE A
BROAD UPPER TROUGH MOVING OVER THE STATE. NONE OF THESE PATTERNS
LOOKS LIKE THEY WILL HAVE THE STRENGTH TO GENERATE SIGNIFICANT
SHOWER ACTIVITY...BUT UNCERTAINTY EXISTS OVER HOW MUCH LOW LEVEL
MOISTURE WILL ADVECT INTO THE REGION WHILE A SURFACE LOW RESIDES
OVER EASTERN COLORADO FROM WEDNESDAY THROUGH SATURDAY.
THEREFORE...WILL NOT MAKE ANY BIG CHANGES TO THE PREVIOUS
FORECAST. IT STILL LOOKS LIKE THURSDAY...FRIDAY AND SATURDAY WILL
BE WARMER THAN NORMAL BEFORE A COOL SURGE MOVES IN SATURDAY NIGHT
CAUSING COOLER TEMPERATURES ON SUNDAY AND MONDAY. AT THAT
TIME...THE ECMWF AND GFS INDICATE THERE WILL ALSO BE A BROAD UPPER
TROUGH OVER THE STATE WHICH MAY HELP ORGANIZE SOME SHOWER
ACTIVITY...ASSUMING ENOUGH MOISTURE IS PRESENT TO FEED INTO THE
DEVELOPING CONVECTION. SATURDAY EVENING COULD ALSO BE A LITTLE BIT
BREEZY AROUND THE PASSAGE OF THE UPPER TROUGH AXIS.
AVIATION...DRAINAGE WINDS EARLY THIS MORNING WILL BECOME LIGHT
NWLY BY 16Z AND THEN MORE NLY BY 18Z. BY 21Z WINDS WILL BECOME
MORE ENE WITH SPEEDS AROUND 10 MPH AND THEN ELY BY 00Z. THERE
COULD BE ISOLD HIGH BASED TSTMS MAINLY AFTER 23Z WHICH COULD
PRODUCE SOME VARIABLE GUSTY WINDS FOR A BRIEF PERIOD OF TIME. AT
THIS TIME WILL JUST MENTION VCTS IN THE 23Z-03Z TIME PERIOD. WINDS
EARLY THIS EVENING WILL BECOME MORE SELY AND THEN MAY TREND MORE
SWLY AFTER 03Z. A COOL FRONT MAY AFFECT THE AIRPORT BY 12Z WED
WITH WINDS BECOMING MORE NLY.
HYDROLOGY...RAINFALL AMOUNTS WILL BE UNDER ONE QUARTER INCH SO NO
ISSUES ARE EXPECTED.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...COOPER
LONG TERM....DANKERS
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS DES MOINES IA
643 AM CDT TUE MAY 14 2013
...UPDATED AVIATION DISCUSSION...
.SHORT TERM.../TODAY /...
ISSUED AT 407 AM CDT TUE MAY 14 2013
FORECAST CHALLENGE TODAY IS WITH RECORD OR
NEAR RECORD HIGH MAX TEMPS...DEW POINTS AND WINDS. MODELS STILL
INITIALIZING TOO MOIST WITH THE RAP CONTINUING TO BE THE DRY
SOLUTION TODAY. RAP ALSO HAS THE BETTER HANDLE ON THE TEMPS
TODAY...SO LEANED CLOSER TO THE RAP SOLUTION.
WINDS WILL INCREASE LATE THIS MORNING AND CONTINUE TO MIX DURING THE
AFTERNOON WITH RAP SHOWING THE BEST DRY ADIABATIC SOUNDING. MIXING
TO 850MB SHOULD TAP INTO THE +25C TEMPERATURES ADVECTING INTO
WESTERN TO NORTHERN IOWA BY THIS AFTERNOON. NAM/GFS/ECMWF SOUNDINGS
ARE NOT AS AGGRESSIVE WITH THE MIXING TODAY...AND POSSIBLY ONE
REASON THESE MODELS OVERDOING THE DEW POINTS. TEMPS OVERNIGHT
REMAINING IN THE UPPER 50S/LOWER 60S ACROSS MUCH OF THE FORECAST
AREA...AND WITH THE NORTHWEST FORECAST AREA RISING 2-4 DEGREES
WARMER MONDAY THAN ANTICIPATED...CONFIDENT ENOUGH TO TWEAK MAX TEMPS
UP SLIGHTLY OVER THE WEST AND NORTH. WENT ROUGHLY 3 TO 5 DEGREES
ABOVE THE WARMEST GUIDANCE TODAY. WITH THE DRIER DEW POINTS AND RH
VALUES COMBINED WITH THE GUSTY SOUTHWEST WINDS...DECIDED TO UPGRADE
TO A RED FLAG WARNING. SEE FIRE WEATHER DISCUSSION FOR FURTHER
DETAILS.
.LONG TERM.../TONIGHT THROUGH MONDAY/...
ISSUED AT 400 AM CDT TUE MAY 14 2013
THE FRONTAL BOUNDARY WILL DROP SLOWLY SOUTH THROUGH THE STATE
OVERNIGHT BEFORE STALLING IN THE ZONAL FLOW JUST SOUTH INTO
MISSOURI ON WEDNESDAY. MOISTURE REMAINS QUITE LIMITED WITH THE
SYSTEM. ANY SHOWERS AND THUNDERSTORMS THAT DO FORM WILL BE
EXTREMELY HIGH BASED AND ABOVE THE PRIMARY AREA OF FORCING. THIS
COMBINED WITH THE LACK OF ASSOCIATED MOISTURE WILL KEEP ANY
ACTIVITY QUITE SPARSE. BROAD AREA OF LOW PRESSURE WILL BECOME
REFOCUSED OVER WYOMING AND THE WESTERN DAKOTAS THURSDAY INTO
FRIDAY. THIS WILL HELP DRIVE THE FRONTAL BOUNDARY BACK NORTH AS A
WARM FRONT. PRECIPITATION CHANCES WILL CONTINUE MAINLY OVER THE
SOUTH WEDNESDAY BEFORE SPREADING BACK NORTH WITH THE FRONTAL
PASSAGE THROUGH THE END OF THE WEEK.
HAVE MAINTAINED THUNDERSTORM CHANCES ON SATURDAY THOUGH THE SIGNS
BEGINNING TO POINT TO THE STATE BEING IN THE WARM SECTOR WITH THE
WARM FRONT MOVING NORTH OF THE STATE. WARM AIR ALOFT WOULD LEAVE A
FAIR AMOUNT OF CONVECTIVE INHIBITION TO OVERCOME ON SATURDAY.
BETTER CHANCE FOR THUNDERSTORMS AND POSSIBLY SEVERE WEATHER WOULD
BE SUNDAY AS A THE UPPER LEVEL RIDGE BEGINS TO BE SHOVED EAST BY
AN UPPER LEVEL SYSTEM ENTERING THE NORTHWESTERN CONUS. THIS WILL
INCREASE THE SOUTHWEST FLOW INTO THE STATE EARLY SUNDAY WITH A
COLD FRONT ARRIVING LATER IN THE DAY. CERTAINLY A FAVORABLE SETUP
FOR SURFACE BASED CONVECTION WITH THE PRIMARY THREATS OF WIND AND
HAIL WITH THE TRIPLE POINT WELL TO THE NORTH...BUT IT IS STILL
SEVERAL DAYS AWAY.
TEMPERATURES THROUGH THE PERIOD WILL BE SEASONAL TO ABOVE NORMAL.
POSSIBLY CLOUD COVER ON WEDNESDAY AND THURSDAY WILL HAVE AN IMPACT
ON TEMPERATURES. THURSDAY ESPECIALLY WILL BE COOLER THAN THE NORTH
DUE TO PRECIPITATION AND CLOUDS. LIKELY A RETURN TO THE 80S ON
SATURDAY WITH DEWPOINTS POSSIBLY RISING INTO THE 60S.
&&
.AVIATION...14/12Z
ISSUED AT 641 AM CDT TUE MAY 14 2013
WINDS WILL INCREASE LATE THIS MORNING AND EXPECTING STRONGEST
WINDS TO MIX DURING THE AFTERNOON. SHOULD SEE SOME GUSTS AT
MCW/DSM/FOD TO AROUND 30 KNOTS...SLIGHTLY LESS AT ALO/OTM.
OTHERWISE...VFR CONDITIONS WILL PREVAIL.
&&
.FIRE WEATHER...
STRONGEST WIND GUSTS AND LOWEST RELATIVE HUMIDITY VALUES ARE
EXPECTED BETWEEN NOON AND 7PM TODAY OVER WESTERN AND NORTHERN
PORTIONS OF THE FORECAST AREA. RH VALUES RANGING FROM 17 TO 22
PERCENT AND SUSTAINED WINDS AROUND 25 MPH OR SLIGHTLY HIGHER ARE
LIKELY DURING THE AFTERNOON. GFDI VALUES RANGES IN THE MODERATE TO
HIGH CATEGORY PAST NOON TODAY AND MAY BARELY BUMP INTO THE EXTREME
CATEGORY FOR A FEW HOURS BETWEEN 2PM AND 5PM THIS AFTERNOON.
MIXING HEIGHT LOOKS TO BE IN THE 3000 TO 3500 FEET LATE THIS
MORNING AND INTO THE AFTERNOON...WITH A SHORT STINT OF MIXING
HIGHER. REPLACED THE FIRE WEATHER WATCH WITH A RED FLAG WARNING
DUE TO THE VERY LOW RH VALUES...STRONG WINDS...AND FUELS NOT
ENTIRELY GREEN YET.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
ADAIR-ADAMS-AUDUBON-BOONE-CALHOUN-CARROLL-CASS-CERRO GORDO-
CRAWFORD-DALLAS-EMMET-FRANKLIN-GREENE-GUTHRIE-HAMILTON-HANCOCK-
HUMBOLDT-KOSSUTH-PALO ALTO-POCAHONTAS-SAC-WEBSTER-WINNEBAGO-
WORTH-WRIGHT.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...DONAVON
AVIATION...PODRAZIK
FIRE WEATHER...PODRAZIK
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
633 AM CDT TUE MAY 14 2013
.FIRE WEATHER...
ISSUED AT 440 AM CDT TUE MAY 14 2013
A RED FLAG WARNING NOW COVERS ALL OF OUR MN COUNTIES FOR THIS
AFTERNOON AND EARLY EVENING. A DRY SURGE OF HEAT WILL OCCUR TODAY
WITH AFTERNOON HUMIDITY VALUES LOWERING TO A FEW PERCENT ABOVE AND
BELOW 20. THE VERY LOW HUMIDITY COUPLED WITH SOUTHWEST TO WEST
WINDS FROM 20 TO 25 MPH ...WITH GUSTS TO 35 MPH... COULD LEAD TO
DANGEROUS WILDFIRE CONDITIONS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 440 AM CDT TUE MAY 14 2013
THERE ARE MANY CONCERNS TODAY AS A LOW PRESSURE SYSTEM AND COLD
FRONT MOVE ACROSS THE FA DURING THE AFTERNOON AND EVENING. A SMALL
COMPLEX OF THUNDERSTORMS DID DEVELOP OVER NORTH DAKOTA OVERNIGHT AS
EXPECTED. THIS AREA OF PRECIPITATION WILL ADVANCE ACROSS NORTHERN
MN THIS MORNING. CONSENSUS FROM THE WRF MODELS WAS LITTLE
(SPRINKLES) OR NOTHING REACHING DOWN INTO CENTRAL MN OTHER THAN
SOME CLOUDS. BY LATE MORNING...THE LOW AND COLD FRONT SHOULD BE
INTO FAR WESTERN AREAS OF MN. SOUTH TO SOUTHWEST WINDS WILL INCREASE
AHEAD OF THE FRONT WHILE RATHER STRONG WEST/NORTHWEST WINDS OCCUR
IN THE WAKE OF THE FRONT. A LOW LEVEL THERMAL RIDGE WILL ADVANCE
NORTHEAST FROM THE CENTRAL PLAINS AND REACH INTO THE TWIN CITIES
BY LATE IN THE AFTERNOON. THE SHORT TERM MODELS REMAIN CONSISTENT
ON 23-26 DEG C AIR AT 850MB FROM THE TWIN CITIES ON SOUTHWEST INTO
NORTHERN IA RESPECTIVELY. HIGHS RECENTLY TO OUR WEST AND NORTHWEST
(CANADA) HAVE BEEN RUNNING REAL CLOSE TO 20 DEGREES ABOVE THESE
CONVERTED VALUES. THIS WOULD YIELD HIGHS FROM 93 TO 99 DEGREES.
AS A RESULT... OUR CURRENT FORECAST WAS RAISED A FEW DEGREES...
ESPECIALLY ACROSS SOUTH CENTRAL MN... WHERE THE RAP SOUNDINGS WERE
SHOWING HIGHS OF 100-103. THIS ALSO RESULTED IN A RECORD HIGH BEING
FORECAST FOR THE TWIN CITIES.
THE HEAT TODAY HAS LEAD TO THE ISSUANCE OF A HEAT ADVISORY FROM
THE TWIN CITIES ON SOUTH AND SOUTHWEST TO ALBERT LEA AND REDWOOD
FALLS. THIS IS A DRY HEAT BEING ACCOMPANIED BY 20 TO 25 MPH WINDS
DURING THE AFTERNOON... WHICH MAY LEAD TO DEHYDRATION ISSUES FOR
THOSE WORKING OUTSIDE. ANOTHER IMPORTANT ISSUE IS THAT THE TWIN
CITIES HAS ONLY BEEN IN THE 80S ONCE SO FAR THIS YEAR WITH 81
DEGREES ON APRIL 28TH. THIS BURST OF HEAT MAY LEAD TO HEALTH
ISSUES.
ANOTHER CONCERN TODAY IS THE POTENTIAL FOR WIND ADVISORY CRITERIA
BEING MET IN THE NORTHWEST CWA IN THE MID TO LATE AFTERNOON HOURS.
THE RAP LOW LEVEL WINDS IN THE 200-300 FOOT RANGE ARE FORECAST IN
THE UPPER 20 KNOT RANGE. THIS IS THE HIGHEST OF ALL THE GUIDANCE.
THE NAM WINDS WERE MORE IN THE 23-24 KNOT RANGE WHICH BLENDED WELL
WITH THE LAMP GUIDANCE. CRITERIA FOR A WIND ADVISORY HAS A BETTER
CHANCE OF BEGIN MET OVER NORTH DAKOTA. AT THIS POINT WE HELD OFF
ON ISSUING AN ADVISORY.
FINALLY...ALTHOUGH A STRONG CAP EXISTS IN THE 700-750MB RANGE
TODAY...THERE REMAINS SOME POTENTIAL FOR CONVECTION TO BREACH THE
CAP AND DEVELOP DURING THE LATE AFTERNOON/EVENING ALONG THE
FRONT... MAINLY TO THE EAST AND SOUTH OF THE TWIN CITIES. WE KEPT
THE SMALL CHANCES FOR THUNDERSTORMS AS IS. OUR LOCAL WRF WAS THE
MOST AGGRESSIVE WITH ACTIVITY DEVELOPING FROM JUST SOUTH OF THE
TWIN CITIES TO OMAHA AROUND 21Z...WHILE THE NMM WRF HAS SOME
STORMS JUST EAST OF US. MOST OF THE SOLUTIONS SHOW A HIGHER CHANCE
FOR STORMS OVER IA TONIGHT AS WELL AS IN NORTHEAST WI. GIVEN THE
SHEAR FORECAST...STORMS THAT DO DEVELOP COULD BECOME SEVERE WITH
LARGE HAIL AND DAMAGING WINDS... ESPECIALLY WITH THE INVERTED V
SOUNDING. NAM DOWNDRAFT CAPE VALUES ARE ON THE ORDER OF 1000 J/KG
OVER WEST CENTRAL WI AND SE MN LATE THIS AFTERNOON AND EVENING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 415 AM CDT TUE MAY 14 2013
WEDNESDAY THROUGH MONDAY...QUIET AND SEASONABLE WEATHER WILL GIVE
WAY TO A WETTER PATTERN AT THE END OF THE PERIOD. SEVERE WEATHER IS
ALSO POSSIBLE FOR THE WEEKEND. EARLY MORNING NORTHERN HEMISPHERIC IR
IMAGERY TOGETHER WITH THE ECMWF 250MB HEIGHTS AND WINDS IDENTIFIED
ZONAL FLOW ACROSS THE WESTERN CONUS...WITH A LOW AMPLITUDE PATTERN
ACROSS THE PACIFIC. FOR WEDNESDAY AND THURSDAY THIS ZONAL FLOW WILL
SET UP ACROSS INTERNATIONAL BORDER...WITH NEGATIVE VORTICITY
ADVECTION AND WEAK SUBSIDENCE ACROSS THE UPPER MIDWEST. THIS WILL
RESULT IN TWO DRY DAYS WITH LIGHT WINDS AND TEMPERATURES 5 TO 10
DEGREES ABOVE THE SEASONAL AVERAGE FOR MID MAY.
BY THURSDAY NIGHT THE AFOREMENTIONED LOW AMPLITUDE JET ACROSS THE
PACIFIC WILL BEGIN TO DIG ACROSS THE WESTERN US...WITH A BROAD AREA
OF LEE SIDE TROUGHING ALONG THE EASTERN SPINE OF THE ROCKIES. THIS
WILL INDUCE SOUTHERLY FLOW WITH GULF MOISTURE TRANSPORT ACROSS THE
CENTRAL CONUS...AND GRADUALLY BUILD AN UPPER LEVEL RIDGE THURSDAY
NIGHT INTO FRIDAY. MEANWHILE THE COLD FRONT THAT WILL HAVE PASSED
THROUGH THE AREA ON TUESDAY AND STALL OUT ACROSS SOUTHERN IOWA WILL
LIFT NORTHWARD AS A WARM FRONT. LOW LEVEL THETA_E ADVECTION AS SEEN
IN THE H925-850 LAYER SHOULD PROMOTE THUNDERSTORM DEVELOPMENT ALONG
THE WARM FRONT...WHILE THE UPPER LEVEL ANTICYCLONIC FLOW ALOFT
ALLOWS EVACUATES THE OUTFLOW FROM THESES STORMS AND ALLOWS THEM TO
PERSIST. DIFFICULT TO QUANTIFY THE CONVECTIVE POTENTIAL SINCE THE
LOW LEVEL MOISTURE HAS BEEN UNRELIABLE LATELY. HOWEVER...THE
SYNOPTIC SETUP WITH GULF MOISTURE ADVECTION INCREASES CONFIDENCE
THAT THESE MOISTURE DEPENDENT VARIABLES...A.K.A. CAPE...ARE
REASONABLY REPRESENTED. DEEP LAYER SHEAR PROFILES VARY DEPENDING ON
THE TIMING AND PLACEMENT OF THE WARM FRONT...BUT BOTH THE 14.12 GFS
AND ECMWF ARE IN GOOD AGREEMENT AND LIFT THE FRONT THROUGH THE CWA
ON FRIDAY. MEANWHILE THE UPPER LEVEL JET WILL CONTINUE TO CARVE OUT
A TROUGH OVER THE FOUR CORNERS REGION. THE GFS...GEM...AND ECMWF ALL
DEVELOP A SURFACE LOW AND TRACK IT ACROSS THE UPPER MIDWEST FOR THE
WEEKEND...BRINGING CONTINUED CHANCES FOR PRECIP. THE RUN TOTAL
PRECIP FROM THE GFS AND ECMWF INDICATE THAT OVER 3 INCHES OF RAIN
ARE POSSIBLE. WITH THIS PROLONGED PERIOD OF PRECIP. IN
SUMMATION...EXPECT AN MCS TO DEVELOP THURSDAY NIGHT AND MOVE ACROSS
THE REGION FRIDAY AS THE WARM FRONT LIFTS NORTHWARD. THEN WILL SEE
CONTINUES CHANCES FOR THUNDERSTORMS SATURDAY AND SUNDAY AS THE UPPER
LEVEL DYNAMICS BECOME MORE FAVORABLE FOR ASCENT. SEVERE WEATHER
REMAINS POSSIBLE...BUT CONFIDENCE IN THE EXACT PLACEMENT OF THE
MESOSCALE FEATURES IS LOW AT THIS TIME.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 548 AM CDT TUE MAY 14 2013
A COLD FRONT ACROSS THE EASTERN DAKOTAS WILL MOVE INTO WESTERN MN
BY 15Z. THE FRONT SHOULD REACH THE TWIN CITIES AROUND 22Z AND PASS
KEAU BY 15/02Z. SOME STORMS HAVE DEVELOPED ALONG THE FRONT THIS
MORNING AND WILL BE PASSING THROUGH KAXN THROUGH 15Z. GUSTY WINDS
TO 40 KNOTS MAY OCCUR WITH THESE STORMS. THE ACTIVITY IS EXPECTED
TO WANE DURING THE MORNING AS A MID LEVEL CAP DEVELOPS. THIS
SHOULD HOLD OFF CONVECTION OVER EASTERN AREAS FOR MUCH OF THE
AFTERNOON... BUT BY 22Z OR SO SEVERAL WRF MODELS ARE HINTING AT
STORMS DEVELOPING JUST SOUTH AND EAST OF KMSP. THE SITE WITH THE
GREATEST RISK FOR SEEING A STORM IS KEAU AND A PROB GROUP FOR TSRA
REMAINS. ANOTHER CONCERN TODAY IS THE WIND. THE PREVIOUS TAF
FORECASTS HAD THIS HANDLED WELL AND LITTLE CHANGE WAS MADE.
INITIALLY S TO SW WINDS WILL INCREASE AHEAD OF THE FRONT TO 15
KNOTS WITH GUSTS INTO THE 20-25 KNOT RANGE AND THEN BECOME W TO NW
WITH FROPA NEAR 20 KNOTS WITH GUSTS TO NEAR 30 KNOTS. THE WIND
WILL THEN DIMINISH DURING THE EVENING.
KMSP...SOUTH WINDS (180-200) INCREASING TO 12 KNOTS WITH GUSTS 18
KNOTS BY 16Z THEN BECOMING MORE SW FOR THE AFTERNOON (210-230)
WITH A FURTHER INCREASE TO 15-20 KNOTS. GUSTS AROUND 25 KNOTS WILL
ALSO OCCUR. WEST WINDS AROUND 20 KNOTS FOR THE LATE
AFTERNOON/EVENING PUSH. GUSTS WILL CONTINUE. THERE IS ALSO A
THREAT FOR STORMS TO DEVELOP...BUT AT THIS TIME THEY ARE EXPECTED
TO BE EAST AND SOUTH OF THE AIRFIELD. DIMINISHING WIND AFTER 15/03Z.
/OUTLOOK FOR KMSP/
WED...VFR. NW WINDS 10 KTS.
THU...VFR. LGT AND VRBL WINDS.
FRI...VFR WITH MVFR/-TSRA POSSIBLE. SE WINDS 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...RED FLAG WARNING FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
MNZ041>045-047>070-073>078-082>085-091>093.
HEAT ADVISORY FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
MNZ059>063-065>070-073>077-082>085-091>093.
WI...NONE.
&&
$$
FIRE WEATHER...RAH
SHORT TERM...RAH
LONG TERM...JRB
AVIATION...RAH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
959 AM CDT TUE MAY 14 2013
.UPDATE...
ISSUED AT 959 AM CDT TUE MAY 14 2013
SHOWERS HAVE EXITED THE AREA AND HAVE REMOVED POPS FOR ALL BUT THE
NORTHERN RRV INTO THE LAKE OF THE WOODS AREA FOR POSSIBLE
REDEVELOPMENT THIS AFTERNOON. AS OF 14Z WEST WIND SHIFT JUST EAST
OF BISMARCK NORTH TO MCCLUSKY NEAR RUGBY TO BOTTINEAU. BEHIND THE
FROPA STILL EXPECTING EFFICIENT MIXING TO 750MB...ALLOWING FOR
RAPID WARM UP. GUSTS BETWEEN 40 AND 50 MPH STILL EXPECTED.
UPDATE ISSUED AT 658 AM CDT TUE MAY 14 2013
SHOWERS AND THUNDERSTORMS HAVE BECOME MORE NUMEROUS ACROSS THE
FORECAST AREA...WITH A STRONG LINE SEGMENT PRODUCING SPORADIC
SEVERE (50+ KTS) DOWNBURST WINDS ACROSS BARNES/CASS COUNTIES.
INCREASED POPS TO 100 PERCENT TO ACCOUNT FOR CURRENT CONVECTIVE
ACTIVITY. ISOLATED STRONG TO SEVERE WINDS ARE POSSIBLE ELSEWHERE
WITH THIS LINE AS ITS FORWARD PROPAGATION IS NEAR 60 MPH. PERSONS
IN THE PATH OF THIS STORM SHOULD PAY CLOSE ATTENTION TO THE LATEST
STATEMENTS AND/OR WARNINGS. REST OF THE FORECAST OK FOR NOW WITH
NO OTHER MAJOR CHANGES.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 355 AM CDT TUE MAY 14 2013
FORECAST CHALLENGES INCLUDE SHOWERS AND THUNDERSTORMS THIS
MORNING...FOLLOWED BY STRONG WINDS AND CRITICAL FIRE WEATHER
CONDITIONS THIS AFTERNOON. GFS/NAM/ECMWF/GEM ARE IN GOOD
AGREEMENT...BUT WILL USE LATEST HRRR FOR PRECIPITATION TRENDS
THROUGH 18 UTC. THEREAFTER...A BLENDED SOLUTION SHOULD SUFFICE.
08 UTC WATER VAPOR LOOP SHOWS A STRONG...YET PROGRESSIVE SHORT
WAVE MOVING ALONG THE CANADIAN BORDER AND INTO NORTHEAST MT. A
CLUSTER OF SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ACROSS CENTRAL
ND IN AN AREA OF WEAK ELEVATED INSTABILITY AND INCREASED
DIVERGENCE ALOFT AHEAD OF A SURFACE COLD FRONT WHICH STRETCHES
FROM NEAR WILLISTON TO MILES CITY MT. LATEST HRRR SHOWS THIS
CONVECTIVE ACTIVITY MOVING EASTWARD THROUGH THE EARLY MORNING AND
INTO THE MN ARROWHEAD AFTER 15 UTC. INCREASED POPS FROM 60 TO 80
PERCENT ACROSS THE NORTHERN HALF OF THE FORECAST AREA THIS MORNING
WHERE A QUICK QUARTER INCH OF RAIN IS POSSIBLE... ESPECIALLY FOR
THOSE AREAS THAT SEE THUNDERSTORMS.
THE COLD FRONT IS FORECAST TO REACH THE VALLEY FLOOR BY 18 UTC.
WITH STRONG LOW-MID LEVEL COLD AIR ADVECTION IN ITS WAKE...AN
ADIABATIC BOUNDARY LAYER TO 750 HPA AND 30 TO 40 KTS TO MIX
DOWN...EXPECT WINDY CONDITIONS TO DEVELOP FROM WEST TO EAST
THROUGH THE AFTERNOON. WEST WINDS FROM 30 TO 40 MPH WITH GUSTS UP
TO 50 MPH ACROSS THE HIGHER TERRAIN OF EASTERN ND NECESSITATES A
WIND ADVISORY FROM 17 TO 02 UTC FOR ALL AREAS EXPECT THE FAR
EASTERN COUNTIES. WILL CANCEL THE HIGH WIND WATCH AS WINDS ARE NOT
EXPECTED TO REACH CRITERIA. HIGH TEMPERATURES TODAY STILL
EXPECTED TO CLIMB INTO THE MID 70S TO MID 80S BEFORE FRONTAL
PASSAGE AND WHEN COMBINED WITH STRONG WINDS AND LOW RH WILL CREATE
DANGEROUS FIRE WEATHER CONDITIONS. SEE DISCUSSION BELOW FOR MORE
DETAIL.
THIS AFTERNOON THROUGH WEDNESDAY WILL BE DRY AS SURFACE HIGH
PRESSURE BUILDS ACROSS THE REGION. WINDS WILL DIMINISH SOMEWHAT
AFTER SUNSET...BUT REMAIN ELEVATED FROM THE WEST-NORTHWEST TONIGHT
THROUGH WEDNESDAY. TOMORROW WILL BE A BIT COOLER WITH AFTERNOON
HIGHS IN THE 70S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 355 AM CDT TUE MAY 14 2013
WEDNESDAY NIGHT THROUGH MOST OF THURSDAY WILL BE DRY...BUT EXPECT
PRECIPITATION CHANCES TO INCREASE THURSDAY NIGHT AHEAD OF THE NEXT
PACIFIC TROUGH. GFS/ECMWF BOTH SHOW A WIDE SWATH OF SHOWERS AND
STORMS MOVING INTO EASTERN ND BY 12 UTC FRIDAY. INCREASED POPS
INTO THE HIGH CHANCE CATEGORY...BUT IF MODEL TRENDS CONTINUE...
WILL NEED TO INCREASE FURTHER. DON/T EXPECT MUCH TEMPERATURE
CHANGE FROM WEDNESDAY WITH THURSDAY/S HIGHS IN THE 70S.
00Z ECMWF/GFS WERE IN GOOD AGREEMENT WITH OVERALL PATTERN FRI-MON
IN SHOWING A LARGE 500 MB TROUGH OVER THE ROCKIES LIFTING
NORTHEAST INTO THE NRN PLAINS AND EVENTUAL 500 MB LOW FORMATION IN
MINNESOTA. THIS LEADS TO AN EXTENDED PERIOD OF PRECIPITATION
CHANCES THRU THE PD. SHOWWALTERS FROM THE MODELS PROG INDICATE
SOME THUNDERSTORM POTENTIAL FRI-SUN THEN MOSTLY SHOWERS ON MONDAY.
OVER THE 4 DAY PERIOD...SOME HEAVY RAINFALL TOTALS ARE POSSIBLE
SOMEWHERE IN OUR REGION AS PWATS INCREASE TO 1.50 INCHES OVER SE
ND INTO NRN MN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 959 AM CDT TUE MAY 14 2013
EXPECT STRONG WEST- NORTHWEST WIND TO DEVELOP AND CONTINUE THROUGH
THE AFTERNOON WITH GUSTS UP TO 40 KTS POSSIBLE... ESPECIALLY AT
KDVL/KGFK/KFAR. CONDITIONS WILL IMPROVE MARKEDLY LATER THIS
EVENING AND OVERNIGHT.
&&
.FIRE WEATHER...
ISSUED AT 959 AM CDT TUE MAY 14 2013
RED FLAG WARNING CONTINUES FOR ALL OF ERN ND INTO MUCH OF NW/WCNTRL
MN (EXCEPT LAKE OF THE WOODS AND NORTH BELTRAMI REGIONS) FOR 17Z TUE
TO 02Z WED. FUELS REMAIN DRY AND PRIME. WILDFIRE ONGOING NEAR GRYGLA
IN SOUTHEASTERN MARSHALL COUNTY. FUELS REMAIN DRY IN ERN ND AS
WELL...THOUGH PARTS OF NE ND AND FAR NW MN WILL SEE SOME RAINFALL
THIS MORNING. BELIEVE THAT EARLY MORNING LOW PCPN AMTS WILL NOT HAVE
GREAT IMPACT ON DECREASING HUMIDITIES THIS AFTERNOON AS DEEP MIXING
LAYER COMBINES WITH STRONG WEST NORTHWEST WINDS TO YIELD VALUES
BELOW 25 PERCENT EVEN IN WEST CENTRAL MN. WILL MONITOR HUMIDITY
LEVELS THROUGHOUT THE DAY AND ADJUST ACCORDINGLY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...RED FLAG WARNING UNTIL 9 PM CDT THIS EVENING FOR NDZ006>008-
014>016-024-026>030-038-039-049-052>054.
WIND ADVISORY UNTIL 9 PM CDT THIS EVENING FOR NDZ006>008-014>016-
024-026>030-038-039-049-052>054.
MN...RED FLAG WARNING UNTIL 9 PM CDT THIS EVENING FOR MNZ001>005-007-
008-013>017-022>024-027>032-040.
WIND ADVISORY UNTIL 9 PM CDT THIS EVENING FOR MNZ001>005-007-008-
013>016-022-023-027>031-040.
&&
$$
UPDATE...JK
SHORT TERM...ROGERS
LONG TERM...ROGERS/RIDDLE
AVIATION...TG
FIRE WEATHER...WJB
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
658 AM CDT TUE MAY 14 2013
.UPDATE...
ISSUED AT 658 AM CDT TUE MAY 14 2013
SHOWERS AND THUNDERSTORMS HAVE BECOME MORE NUMEROUS ACROSS THE
FORECAST AREA...WITH A STRONG LINE SEGMENT PRODUCING SPORADIC
SEVERE (50+ KTS) DOWNBURST WINDS ACROSS BARNES/CASS COUNTIES.
INCREASED POPS TO 100 PERCENT TO ACCOUNT FOR CURRENT CONVECTIVE
ACTIVITY. ISOLATED STRONG TO SEVERE WINDS ARE POSSIBLE ELSEWHERE
WITH THIS LINE AS ITS FORWARD PROPAGATION IS NEAR 60 MPH. PERSONS
IN THE PATH OF THIS STORM SHOULD PAY CLOSE ATTENTION TO THE LATEST
STATEMENTS AND/OR WARNINGS. REST OF THE FORECAST OK FOR NOW WITH
NO OTHER MAJOR CHANGES.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 355 AM CDT TUE MAY 14 2013
FORECAST CHALLENGES INCLUDE SHOWERS AND THUNDERSTORMS THIS
MORNING...FOLLOWED BY STRONG WINDS AND CRITICAL FIRE WEATHER
CONDITIONS THIS AFTERNOON. GFS/NAM/ECMWF/GEM ARE IN GOOD
AGREEMENT...BUT WILL USE LATEST HRRR FOR PRECIPITATION TRENDS
THROUGH 18 UTC. THEREAFTER...A BLENDED SOLUTION SHOULD SUFFICE.
08 UTC WATER VAPOR LOOP SHOWS A STRONG...YET PROGRESSIVE SHORT
WAVE MOVING ALONG THE CANADIAN BORDER AND INTO NORTHEAST MT. A
CLUSTER OF SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ACROSS CENTRAL
ND IN AN AREA OF WEAK ELEVATED INSTABILITY AND INCREASED
DIVERGENCE ALOFT AHEAD OF A SURFACE COLD FRONT WHICH STRETCHES
FROM NEAR WILLISTON TO MILES CITY MT. LATEST HRRR SHOWS THIS
CONVECTIVE ACTIVITY MOVING EASTWARD THROUGH THE EARLY MORNING AND
INTO THE MN ARROWHEAD AFTER 15 UTC. INCREASED POPS FROM 60 TO 80
PERCENT ACROSS THE NORTHERN HALF OF THE FORECAST AREA THIS MORNING
WHERE A QUICK QUARTER INCH OF RAIN IS POSSIBLE... ESPECIALLY FOR
THOSE AREAS THAT SEE THUNDERSTORMS.
THE COLD FRONT IS FORECAST TO REACH THE VALLEY FLOOR BY 18 UTC.
WITH STRONG LOW-MID LEVEL COLD AIR ADVECTION IN ITS WAKE...AN
ADIABATIC BOUNDARY LAYER TO 750 HPA AND 30 TO 40 KTS TO MIX
DOWN...EXPECT WINDY CONDITIONS TO DEVELOP FROM WEST TO EAST
THROUGH THE AFTERNOON. WEST WINDS FROM 30 TO 40 MPH WITH GUSTS UP
TO 50 MPH ACROSS THE HIGHER TERRAIN OF EASTERN ND NECESSITATES A
WIND ADVISORY FROM 17 TO 02 UTC FOR ALL AREAS EXPECT THE FAR
EASTERN COUNTIES. WILL CANCEL THE HIGH WIND WATCH AS WINDS ARE NOT
EXPECTED TO REACH CRITERIA. HIGH TEMPERATURES TODAY STILL
EXPECTED TO CLIMB INTO THE MID 70S TO MID 80S BEFORE FRONTAL
PASSAGE AND WHEN COMBINED WITH STRONG WINDS AND LOW RH WILL CREATE
DANGEROUS FIRE WEATHER CONDITIONS. SEE DISCUSSION BELOW FOR MORE
DETAIL.
THIS AFTERNOON THROUGH WEDNESDAY WILL BE DRY AS SURFACE HIGH
PRESSURE BUILDS ACROSS THE REGION. WINDS WILL DIMINISH SOMEWHAT
AFTER SUNSET...BUT REMAIN ELEVATED FROM THE WEST-NORTHWEST TONIGHT
THROUGH WEDNESDAY. TOMORROW WILL BE A BIT COOLER WITH AFTERNOON
HIGHS IN THE 70S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 355 AM CDT TUE MAY 14 2013
WEDNESDAY NIGHT THROUGH MOST OF THURSDAY WILL BE DRY...BUT EXPECT
PRECIPITATION CHANCES TO INCREASE THURSDAY NIGHT AHEAD OF THE NEXT
PACIFIC TROUGH. GFS/ECMWF BOTH SHOW A WIDE SWATH OF SHOWERS AND
STORMS MOVING INTO EASTERN ND BY 12 UTC FRIDAY. INCREASED POPS
INTO THE HIGH CHANCE CATEGORY...BUT IF MODEL TRENDS CONTINUE...
WILL NEED TO INCREASE FURTHER. DON/T EXPECT MUCH TEMPERATURE
CHANGE FROM WEDNESDAY WITH THURSDAY/S HIGHS IN THE 70S.
00Z ECMWF/GFS WERE IN GOOD AGREEMENT WITH OVERALL PATTERN FRI-MON
IN SHOWING A LARGE 500 MB TROUGH OVER THE ROCKIES LIFTING
NORTHEAST INTO THE NRN PLAINS AND EVENTUAL 500 MB LOW FORMATION IN
MINNESOTA. THIS LEADS TO AN EXTENDED PERIOD OF PRECIPITATION
CHANCES THRU THE PD. SHOWWALTERS FROM THE MODELS PROG INDICATE
SOME THUNDERSTORM POTENTIAL FRI-SUN THEN MOSTLY SHOWERS ON MONDAY.
OVER THE 4 DAY PERIOD...SOME HEAVY RAINFALL TOTALS ARE POSSIBLE
SOMEWHERE IN OUR REGION AS PWATS INCREASE TO 1.50 INCHES OVER SE
ND INTO NRN MN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 658 AM CDT TUE MAY 14 2013
AN AREA OF SHOWERS AND THUNDERSTORMS ALONG AND EAST OF THE VALLEY
WILL MOVE RAPIDLY INTO THE MN ARROWHEAD LATER THIS MORNING.
CEILINGS ARE VFR...BUT BRIEF HIGH WIND GUSTS ARE POSSIBLE WITH THE
LEADING EDGE OF STORMS. EXPECT STRONG WEST-NORTHWEST WIND TO
DEVELOP LATER THIS MORNING AND CONTINUE THROUGH THE AFTERNOON WITH
GUSTS UP TO 40 KTS POSSIBLE...ESPECIALLY AT KDVL/KGFK/KFAR.
CONDITIONS WILL IMPROVE MARKEDLY LATER THIS EVENING AND OVERNIGHT.
&&
.FIRE WEATHER...
ISSUED AT 355 AM CDT TUE MAY 14 2013
WILL ISSUE RED FLAG WARNING FOR ALL OF ERN ND INTO MUCH OF NW/WCNTRL
MN (EXCEPT LAKE OF THE WOODS AND NORTH BELTRAMI REGIONS) FOR 17Z TUE
TO 02Z WED. EVENING DISCUSSION WITH MN FIRE AGENCY INDICATES FUELS
ARE DRY AND PRIME. WILDFIRE ONGOING NEAR GRYGLA IN SOUTHEASTERN
MARSHALL COUNTY. FUELS REMAIN DRY IN ERN ND AS WELL...THOUGH PARTS
OF NE ND AND FAR NW MN WILL SEE SOME RAINFALL THIS MORNING. THE
EXTENT OF RAINFALL THIS MORNING IS STILL UNCERTAIN. AIDING IN FIRE
POTENTIAL IS STRONG WESTERLY WINDS THAT WILL SPREAD EAST BEHIND
THE COLD FRONT INTO ERN ND MIDDAY AND INTO NW/WCNTRL MN THIS AFTN
WITH GUSTS 40-50 MPH IN ERN ND AND 35 TO 45 MPH IN THE PRAIRIE
REGIONS OF NW/WCNTRL MN. THUS RED FLAG WARNING ISSUED. NOW HOURLY
TRENDS OF RELATIVE HUMIDITY WILL BE A CHALLENGE AND VERY DIFFICULT
TO FORECAST FOR DUE TO IMPACTS OF ANY MORNING PRECIP AND LOCATION.
THUS COULD HAVE WIDE VARIATIONS THIS MORNING-MIDDAY UNTIL THE
FRONT AND WESTERLY WINDS ARRIVE.
&&
.HYDROLOGY...
ISSUED AT 1258 PM CDT MON MAY 13 2013
RIVER FLOOD WARNINGS CONTINUE ON THE RED RIVER AT OSLO...DRAYTON
AND PEMBINA. RIVER STAGES AT DRAYTON AND PEMBINA ARE CONTINUING A
SLOW RECESSION...WITH STAGES AT OSLO FALLING MORE RAPIDLY.
OTHERWISE...MOST OTHER POINTS ON THE MAINSTEM RED AND ON THE ND/MN
TRIBUTARIES SHOW RECEDING OR NEARLY STEADY LEVELS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...RED FLAG WARNING FROM NOON TODAY TO 9 PM CDT THIS EVENING FOR
NDZ006>008-014>016-024-026>030-038-039-049-052>054.
WIND ADVISORY FROM NOON TODAY TO 9 PM CDT THIS EVENING FOR
NDZ006>008-014>016-024-026>030-038-039-049-052>054.
MN...RED FLAG WARNING FROM NOON TODAY TO 9 PM CDT THIS EVENING FOR
MNZ001>005-007-008-013>017-022>024-027>032-040.
WIND ADVISORY FROM NOON TODAY TO 9 PM CDT THIS EVENING FOR
MNZ001>005-007-008-013>016-022-023-027>031-040.
&&
$$
UPDATE...ROGERS
SHORT TERM...ROGERS
LONG TERM...ROGERS/RIDDLE
AVIATION...ROGERS
FIRE WEATHER...RIDDLE
HYDROLOGY...SPEICHER
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1038 AM CDT TUE MAY 14 2013
.UPDATE...
ISSUED AT 1029 AM CDT TUE MAY 14 2013
FORECAST LOOKS IN PRETTY GOOD SHAPE. RED FLAG WARNING LOOKS
GOOD...WITH BLUSTERY SOUTHWEST WINDS AHEAD OF THE COLD
FRONT...TRANSITIONING TO NORTHWEST BEHIND IT. EXPECT FREQUENT GUSTS
INTO THE 25 TO 35 MPH RANGE WITH RELATIVE HUMIDITY DROPPING TO AROUND
20 PERCENT...OR EVEN A LITTLE LOWER AHEAD OF THE FRONT THIS
AFTERNOON. LEADING EDGE OF THE ACCAS IS A SOME SORT OF BOUNDARY WITH
WINDS TURNING MORE WEST SOUTHWESTERLY BEHIND IT. HOWEVER THE TRUE
COLD FRONT IS BEHIND THIS...HAVING JUST GONE THROUGH CHAMBERLAIN AND
HURON WITH THEIR WINDS TURNING NORTHWEST. WENT AHEAD AND RAISED
HIGHS A FEW DEGREES FOR TODAY...WITH READINGS AROUND 100 LOOKING
LIKELY ACROSS NORTHEAST NEBRASKA AND NORTHWEST IOWA...LOCATIONS THAT
WILL STAY JUST AHEAD OF THE COLD FRONT THROUGH THE PEAK OF DAYTIME
HEATING. CONVECTION CHANCES WITH THE FRONT STILL LOOK LOW WITH
DEWPOINTS MIXING OUT. HOWEVER HRRR IS SHOWING SOME ACTIVITY AFTER
21Z. AND GIVEN THAT ITS BOUNDARY LAYER DEPICTION SEEMS DECENT...CAN
NOT COMPLETELY IGNORE THE CHANCE. HOWEVER IT DOES APPEAR THAT THE
BEST CHANCE WILL STAY SOUTH OF OUR CWA ACROSS NEBRASKA...THUS WILL
KEEP THE FORECAST DRY FOR NOW. ALTHOUGH ANY STORM THAT IS ABLE TO
FORM WOULD BE CAPABLE OF POTENTIALLY SEVERE WIND GUSTS GIVEN THE DRY
PROFILES.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CDT TUE MAY 14 2013
MAIN CHALLENGE FOR TODAY WILL BE WINDS/HUMIDITY LEVELS/ASSOCIATED
FIRE WEATHER CONCERNS IN MIXY ENVIRONMENT AHEAD OF AND BEHIND COOL
FRONT WHICH WILL PUSH SOUTHEAST ACROSS THE REGION THROUGH THE DAY.
LOW LEVEL TEMPERATURES AHEAD OF THE FRONT EASILY SUPPORTIVE OF MID
90S ACROSS MUCH OF NORTHWEST IOWA THIS AFTERNOON...WITH SOME MODELS
SHOWING POTENTIAL FOR HIGHS CLOSER TO OR JUST ABOVE THE CENTURY MARK.
WITH THE STRONG MIXING COMES LIKELIHOOD OF MIXING DRIER AIR ALOFT TO
THE SURFACE. MODELS HAVE BEEN HAVING DIFFICULTY CAPTURING THE DIURNAL
DRYING TREND WITH AFTERNOON MIXING...HANGING ONTO SHALLOW MOISTURE OR
MIXING BOUNDARY LAYER MOISTURE UPWARD RATHER THAN BRINGING DRIER AIR
TO SURFACE AS DEEPER MIXING COMMENCES. RUC SEEMS TO HANDLE IT BETTER
THAN NAM/GFS...AND MORE CLOSELY FOLLOWED THAT IDEA THROUGH THE LATE
MORNING/AFTERNOON...THOUGH NOT QUITE AS DRY AS RUC INDICATES AT THIS
POINT GIVEN EXTREME DISPARITY FROM OTHER MODELS /AS MUCH AS 10-15F
DRIER THAN MOST OTHER GUIDANCE FOR 21Z/. DRIEST AIR SHOULD BE OVER
FAR SOUTHEAST AND WESTERN PARTS OF THE FORECAST AREA DURING PEAK
HEATING...WITH SLIGHT MOISTURE POOLING IN SOMEWHAT LESS MIXY AREA
RIGHT ALONG THE FRONT...FORECAST TO BE JUST EAST OF KYKN-KFSD-KMML
LINE AT 21Z. ALL THIS LEADS TO MINIMUM HUMIDITY LEVELS OF 15-25
PERCENT THIS AFTERNOON... AND THIS ALONG WITH WINDS GUSTING IN THE
25-30KT RANGE STILL SUPPORTIVE OF RED FLAG WARNING WHICH WAS ISSUED
ON THE DAY SHIFT YESTERDAY.
COLD FRONT SETTLES SOUTH OF THE AREA TONIGHT...WITH COOLING
TEMPERATURES AND DYING WINDS OVERNIGHT. LOWS LOOK TO DROP INTO THE
UPPER 40S NORTHWEST...TO MID 50S THROUGH THE LOWER MISSOURI RIVER
VALLEY INTO NORTHWESTERN IOWA.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 343 AM CDT TUE MAY 14 2013
SURFACE HIGH PRESSURE BUILDS SOUTHWARD INTO THE REGION ON WEDNESDAY
AND WEDNESDAY NIGHT...PROVIDING FOR PLEASANT CONDITIONS WITH
TEMPERATURES CLOSE TO NORMAL FOR THIS TIME OF YEAR. THIS WILL PLAY
OUT TO HIGHS IN THE MID AND UPPER 70S...WITH LOWS EARLY ON THURSDAY
IN THE UPPER 40S TO LOWER 50S.
THE HIGH MOVES EASTWARD ON THURSDAY WITH A SOUTHERLY FLOW RETURNING
TO OUR AREA ON THE BACKSIDE OF THE HIGH. THINK MOST OF THE DAY WILL
REMAIN DRY WITH WARMING TEMPERATURES...INTO THE UPPER 70S TO AROUND
80 FOR AFTERNOON HIGHS. CANNOT RULE OUT SOME THUNDERSTORM
DEVELOPMENT IN OUR SOUTHWEST LATER IN THE AFTERNOON...WITH A BETTER
CHANCE ON THURSDAY NIGHT AS A WARM FRONT BEGINS TO LIFT THROUGH
NEBRASKA AND 850 MB CONVERGENCE IS ENHANCED AS A LOW LEVEL JET
DEVELOPS THROUGH THE REGION. DOES APPEAR TO BE ENOUGH ELEVATED
CAPE...500 TO 1000 J/KG...AND EFFECTIVE SHEAR OF AROUND 30 KTS IN
THE EVENING THAT CANNOT RULE OUT A COUPLE OF SEVERE STORMS WITH
LARGE HAIL.
A MESSY PATTERN CONTINUES THROUGH THE EXTENDED...FRIDAY INTO MONDAY
OF NEXT WEEK...WITH PERIODIC CHANCES OF CONVECTION THROUGH THE
PERIOD WITH A BOUNDARY MEANDERING AROUND THE AREA AND A SERIES OF
SUBTLE WAVES TRACKING ACROSS THE REGION. HARD TO TIME THIS
CONVECTION DEPENDENT ON WHERE SYNOPTIC/MESOSCALE FEATURES SET
UP...BUT WITH INCREASING LOW LEVEL MOISTURE AND INSTABILITY ACROSS
THE REGION THROUGH THE WEEKEND THERE IS FAIRLY HIGH CONFIDENCE THAT
CONVECTION WILL OCCUR. CONVECTIVE PARAMETERS WOULD ALSO SUGGEST THAT
SEVERE STORMS WILL BE POSSIBLE FOR THOSE DAYS. AN UPPER LEVEL TROUGH
FINALLY SWINGS OUT OF THE WESTERN U.S. ON SUNDAY AND
MONDAY...KEEPING A CHANCE OF CONVECTION ACROSS THE REGION...AS WELL
AS BRINGING A COOLING TREND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 634 AM CDT TUE MAY 14 2013
MAIN AVIATION CONCERN TODAY WILL BE GUSTY WINDS...FIRST OUT OF THE
SOUTHWEST BY 14Z AHEAD OF APPROACHING COLD FRONT...WITH THE WINDS
BECOMING NORTHWEST AS THE FRONT PROGRESSES SOUTHEAST ACROSS THE
FORECAST AREA THROUGH THE DAY. GUSTY WINDS WILL SUBSIDE WITH SUNSET
AROUND 15/01Z. VFR CONDITIONS THROUGH THE PERIOD.
&&
.FIRE WEATHER...
ISSUED AT 343 AM CDT TUE MAY 14 2013
RED FLAG WARNING STILL LOOKS WARRANTED FOR THE AFTERNOON AND EARLY
EVENING. GUSTY SOUTHWEST WINDS OF 25 TO 35 MPH AHEAD OF COOL FRONT
WILL SWITCH TO NORTHWEST BEHIND THE FRONT AND REMAIN AS STRONG. ALONG
WITH THE GUSTY WINDS WILL BE DRY RELATIVE HUMIDITY LEVELS IN THE 15
TO 25 PERCENT RANGE...AS DRY AND UNSEASONABLY WARM AIR ALOFT MIXES TO
THE SURFACE. AREAS RIGHT ALONG THE FRONT MAY NOT SEE AS SUSTAINED A
PERIOD OF RED FLAG CRITERIA DUE TO MOISTURE POOLING AND LIGHTER/LESS
GUSTY WINDS WITHIN THE FRONTAL ZONE...BUT SHOULD STILL REACH CRITERIA
AT TIMES. RECENT GREENING OF COOL SEASON GRASSES MAY SLOW FIRE STARTS
ACROSS THE AREA...BUT ANY FIRES THAT DO IGNITE WILL SPREAD VERY
QUICKLY IN THE LINGERING DORMANT TALL GRASSES.
SOME MODELS ALSO INDICATE POTENTIAL FOR EVEN WARMER/DRIER AIR MIXING
TO THE SURFACE AHEAD OF THE FRONT...MAINLY IN NORTHWEST IOWA THIS
AFTERNOON...SO THIS WILL BE WATCHED CLOSELY THROUGHOUT THE DAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR SDZ255>258.
MN...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR MNZ900.
IA...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR IAZ300-301.
NE...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR NEZ249.
&&
$$
UPDATE...CHENARD
SHORT TERM...JH/JM
LONG TERM...JM
AVIATION...JH
FIRE WEATHER...JH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
634 AM CDT TUE MAY 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CDT TUE MAY 14 2013
MAIN CHALLENGE FOR TODAY WILL BE WINDS/HUMIDITY LEVELS/ASSOCIATED
FIRE WEATHER CONCERNS IN MIXY ENVIRONMENT AHEAD OF AND BEHIND COOL
FRONT WHICH WILL PUSH SOUTHEAST ACROSS THE REGION THROUGH THE DAY.
LOW LEVEL TEMPERATURES AHEAD OF THE FRONT EASILY SUPPORTIVE OF MID
90S ACROSS MUCH OF NORTHWEST IOWA THIS AFTERNOON...WITH SOME MODELS
SHOWING POTENTIAL FOR HIGHS CLOSER TO OR JUST ABOVE THE CENTURY MARK.
WITH THE STRONG MIXING COMES LIKELIHOOD OF MIXING DRIER AIR ALOFT TO
THE SURFACE. MODELS HAVE BEEN HAVING DIFFICULTY CAPTURING THE DIURNAL
DRYING TREND WITH AFTERNOON MIXING...HANGING ONTO SHALLOW MOISTURE OR
MIXING BOUNDARY LAYER MOISTURE UPWARD RATHER THAN BRINGING DRIER AIR
TO SURFACE AS DEEPER MIXING COMMENCES. RUC SEEMS TO HANDLE IT BETTER
THAN NAM/GFS...AND MORE CLOSELY FOLLOWED THAT IDEA THROUGH THE LATE
MORNING/AFTERNOON...THOUGH NOT QUITE AS DRY AS RUC INDICATES AT THIS
POINT GIVEN EXTREME DISPARITY FROM OTHER MODELS /AS MUCH AS 10-15F
DRIER THAN MOST OTHER GUIDANCE FOR 21Z/. DRIEST AIR SHOULD BE OVER
FAR SOUTHEAST AND WESTERN PARTS OF THE FORECAST AREA DURING PEAK
HEATING...WITH SLIGHT MOISTURE POOLING IN SOMEWHAT LESS MIXY AREA
RIGHT ALONG THE FRONT...FORECAST TO BE JUST EAST OF KYKN-KFSD-KMML
LINE AT 21Z. ALL THIS LEADS TO MINIMUM HUMIDITY LEVELS OF 15-25
PERCENT THIS AFTERNOON... AND THIS ALONG WITH WINDS GUSTING IN THE
25-30KT RANGE STILL SUPPORTIVE OF RED FLAG WARNING WHICH WAS ISSUED
ON THE DAY SHIFT YESTERDAY.
COLD FRONT SETTLES SOUTH OF THE AREA TONIGHT...WITH COOLING
TEMPERATURES AND DYING WINDS OVERNIGHT. LOWS LOOK TO DROP INTO THE
UPPER 40S NORTHWEST...TO MID 50S THROUGH THE LOWER MISSOURI RIVER
VALLEY INTO NORTHWESTERN IOWA.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 343 AM CDT TUE MAY 14 2013
SURFACE HIGH PRESSURE BUILDS SOUTHWARD INTO THE REGION ON WEDNESDAY
AND WEDNESDAY NIGHT...PROVIDING FOR PLEASANT CONDITIONS WITH
TEMPERATURES CLOSE TO NORMAL FOR THIS TIME OF YEAR. THIS WILL PLAY
OUT TO HIGHS IN THE MID AND UPPER 70S...WITH LOWS EARLY ON THURSDAY
IN THE UPPER 40S TO LOWER 50S.
THE HIGH MOVES EASTWARD ON THURSDAY WITH A SOUTHERLY FLOW RETURNING
TO OUR AREA ON THE BACKSIDE OF THE HIGH. THINK MOST OF THE DAY WILL
REMAIN DRY WITH WARMING TEMPERATURES...INTO THE UPPER 70S TO AROUND
80 FOR AFTERNOON HIGHS. CANNOT RULE OUT SOME THUNDERSTORM
DEVELOPMENT IN OUR SOUTHWEST LATER IN THE AFTERNOON...WITH A BETTER
CHANCE ON THURSDAY NIGHT AS A WARM FRONT BEGINS TO LIFT THROUGH
NEBRASKA AND 850 MB CONVERGENCE IS ENHANCED AS A LOW LEVEL JET
DEVELOPS THROUGH THE REGION. DOES APPEAR TO BE ENOUGH ELEVATED
CAPE...500 TO 1000 J/KG...AND EFFECTIVE SHEAR OF AROUND 30 KTS IN
THE EVENING THAT CANNOT RULE OUT A COUPLE OF SEVERE STORMS WITH
LARGE HAIL.
A MESSY PATTERN CONTINUES THROUGH THE EXTENDED...FRIDAY INTO MONDAY
OF NEXT WEEK...WITH PERIODIC CHANCES OF CONVECTION THROUGH THE
PERIOD WITH A BOUNDARY MEANDERING AROUND THE AREA AND A SERIES OF
SUBTLE WAVES TRACKING ACROSS THE REGION. HARD TO TIME THIS
CONVECTION DEPENDENT ON WHERE SYNOPTIC/MESOSCALE FEATURES SET
UP...BUT WITH INCREASING LOW LEVEL MOISTURE AND INSTABILITY ACROSS
THE REGION THROUGH THE WEEKEND THERE IS FAIRLY HIGH CONFIDENCE THAT
CONVECTION WILL OCCUR. CONVECTIVE PARAMETERS WOULD ALSO SUGGEST THAT
SEVERE STORMS WILL BE POSSIBLE FOR THOSE DAYS. AN UPPER LEVEL TROUGH
FINALLY SWINGS OUT OF THE WESTERN U.S. ON SUNDAY AND
MONDAY...KEEPING A CHANCE OF CONVECTION ACROSS THE REGION...AS WELL
AS BRINGING A COOLING TREND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 634 AM CDT TUE MAY 14 2013
MAIN AVIATION CONCERN TODAY WILL BE GUSTY WINDS...FIRST OUT OF THE
SOUTHWEST BY 14Z AHEAD OF APPROACHING COLD FRONT...WITH THE WINDS
BECOMING NORTHWEST AS THE FRONT PROGRESSES SOUTHEAST ACROSS THE
FORECAST AREA THROUGH THE DAY. GUSTY WINDS WILL SUBSIDE WITH SUNSET
AROUND 15/01Z. VFR CONDITIONS THROUGH THE PERIOD.
&&
.FIRE WEATHER...
ISSUED AT 343 AM CDT TUE MAY 14 2013
RED FLAG WARNING STILL LOOKS WARRANTED FOR THE AFTERNOON AND EARLY
EVENING. GUSTY SOUTHWEST WINDS OF 25 TO 35 MPH AHEAD OF COOL FRONT
WILL SWITCH TO NORTHWEST BEHIND THE FRONT AND REMAIN AS STRONG. ALONG
WITH THE GUSTY WINDS WILL BE DRY RELATIVE HUMIDITY LEVELS IN THE 15
TO 25 PERCENT RANGE...AS DRY AND UNSEASONABLY WARM AIR ALOFT MIXES TO
THE SURFACE. AREAS RIGHT ALONG THE FRONT MAY NOT SEE AS SUSTAINED A
PERIOD OF RED FLAG CRITERIA DUE TO MOISTURE POOLING AND LIGHTER/LESS
GUSTY WINDS WITHIN THE FRONTAL ZONE...BUT SHOULD STILL REACH CRITERIA
AT TIMES. RECENT GREENING OF COOL SEASON GRASSES MAY SLOW FIRE STARTS
ACROSS THE AREA...BUT ANY FIRES THAT DO IGNITE WILL SPREAD VERY
QUICKLY IN THE LINGERING DORMANT TALL GRASSES.
SOME MODELS ALSO INDICATE POTENTIAL FOR EVEN WARMER/DRIER AIR MIXING
TO THE SURFACE AHEAD OF THE FRONT...MAINLY IN NORTHWEST IOWA THIS
AFTERNOON...SO THIS WILL BE WATCHED CLOSELY THROUGHOUT THE DAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...RED FLAG WARNING FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
SDZ255>258.
MN...RED FLAG WARNING FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
MNZ900.
IA...RED FLAG WARNING FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
IAZ300-301.
NE...RED FLAG WARNING FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
NEZ249.
&&
$$
SHORT TERM...JH/JM
LONG TERM...JM
AVIATION...JH
FIRE WEATHER...JH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
627 AM CDT TUE MAY 14 2013
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND WEDNESDAY
ISSUED AT 436 AM CDT TUE MAY 14 2013
FORECAST CONCERNS ON TEMPERATURES TODAY AND CHANCE FOR
THUNDERSTORMS LATER THIS AFTERNOON AND THIS EVENING. HAVE TRENDED
TOWARDS GEM/NAM FOR GUIDANCE ON THIS PACKAGE. ECMWF NOW TRENDING
TOWARDS NAM WITH BETTER CHANCE FOR PCPN A BIT FURTHER SOUTH INTO
CENTRAL WI CLOSER TO WARM FRONT POSITION.
LAST EVENING SOUNDINGS SHOWS WHAT THE ISSUE WITH THIS
FORECAST...THAT BEING TOO DRY. AREA OF HIGH BASED SHOWERS WENT
THROUGH LAST NIGHT AROUND MIDNIGHT ASSOCIATED WITH STRONG WAA/850
WARM FRONT. NOTHING MORE THAN SPRINKLES SEEN. MID CLOUDINESS NOW
EXITING EASTERN WI.
FOCUS ON FAST MOVING SHORT WAVE ALONG CANADIAN BORDER AND FRONTAL
SYSTEM NOW MOVING THROUGH NORTHERN PLAINS. BY MID AFTERNOON...WARM FRONT
TO LIFT NORTH INTO SOUTHWEST WI. RATHER WARM AIR MASS TO PUSH INTO
STATE TODAY WITH 850 TEMPS INTO THE 20S OVER CENTRAL WI. WITH STEEP
MID-LEVEL LAPSE RATES BETWEEN 8 AND 9 C/KM....AND WARM
FRONT...WILL CONTINUE TO CARRY SMALL/ISOLD CHANCE FOR
THUNDERSTORMS. MODEL SOUNDINGS SUGGEST STRONG CIN THROUGH THE DAY
GIVEN DRY AIRMASS BELOW 600MB. SOUNDINGS ALSO SHOW CAPE HIGH
BASED...MAINLY ABOVE 600MB. THIS TO LEAD TO HIGH BASED
THUNDERSTORM THREAT...WHICH IF STORMS DO DEVELOP WOULD LIKELY LEAD TO
GUSTY WINDS...POSSIBLY HAIL. COLD FRONT TO PUSH THROUGH STATE BY
MIDNIGHT LEADING TO DRY FORECAST FOR REST OF NIGHT AND WEDNESDAY.
ON WEDNESDAY...GUSTY NORTHWEST WINDS BEHIND FRONT AND LOW
HUMIDITIES WITH MIXING TO 5K FEET OR HIGHER MAY LEAD TO INCREASED
FIRE DANGER.
TEMPERATURES TO BE WELL ABOVE NORM TODAY...DROPPING CLOSER TO
NORMS ON WEDNESDAY. FEW MODELS...INCLUDING HRRR SUGGEST 90 INTO
SOUTHWEST WI. HAVE BUMPED TEMPS UP SLIGHTLY THROUGHOUT CWA.
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY
ISSUED AT 436 AM CDT TUE MAY 14 2013
SURFACE HIGH PRESSURE MOVING ACROSS THE REGION AHEAD OF AN UPPER
LEVEL RIDGE SHOULD KEEP THE EARLY PART OF THE LONG TERM FORECAST
DRY. THE 00Z NAM AND 00Z GFS GENERATED SOME QPF DURING THE DAY ON
THURSDAY...BUT SINCE THE 00Z ECMWF...PREVIOUS FORECAST AND
SURROUNDING GRIDS WERE DRY...A DRY FORECAST APPEARED TO BE THE WAY
TO GO.
A SHORT WAVE AND WARM ADVECTION AHEAD OF A SURFACE TROUGH
APPROACHING FROM THE PLAINS WILL BRING A CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE AREA STARTING ON FRIDAY. VARIOUS SHORT WAVES
AHEAD OF THE MAIN UPPER TROUGH AND A SURFACE FRONTAL
BOUNDARY...COMBINED WITH A FEED OF GULF MOISTURE AHEAD OF A
DEVELOPING SURFACE LOW WILL KEEP AT LEAST A CHANCE OF SHOWERS AND
THUNDERSTORMS THROUGH THE END OF THE FORECAST PERIOD.
CLOUDS AND PRECIPITATION WILL KEEP TEMPERATURES FROM WARMING TOO
MUCH ABOVE NORMAL DURING THE DAYTIME...BUT THE SAME FACTORS SHOULD
KEEP TEMPERATURES WELL ABOVE NORMAL AT NIGHT.
&&
.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 612 AM CDT TUE MAY 14 2013
LLWS CONDITIONS TO PERSIST THROUGH 15Z IN THE EAST...OTHERWISE VFR
CONDITIONS WILL CONTINUE THROUGH THE PERIOD. ISOLD TO SCT
THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON INTO TONIGHT AS A
WARM/COLD FRONT MOVE THROUGH THE STATE. THUNDERSTORMS EXPECTED TO
BE HIGH BASED WITH STRONG...GUSTY WINDS POSSIBLE WITH ANY THUNDERSTORM
THAT DEVELOPS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....TE
LONG TERM......MG
AVIATION.......TE
AREA FORECAST DISCUSSION
NWS TAUNTON MA
705 PM EDT TUE MAY 14 2013
.SYNOPSIS...
COOL CONDITIONS WILL PERSIST TONIGHT AS A HIGH PRESSURE RIDGE
BUILDS ACROSS NEW ENGLAND. A WARM FRONT WILL APPROACH...BRINGING
SHOWERS INTO THE REGION WEDNESDAY AFTERNOON AND NIGHT. HIGH
PRESSURE BUILDS SOUTH FROM CANADA WITH DRY WEATHER AND SEASONABLE
TEMPERATURES FOR MOST OF THURSDAY THROUGH NEXT TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
7 PM UPDATE...
CLOUDS IN PLACE OVER SOUTHERN NEW ENGLAND MOVING SOUTHEAST.
CONTINUE TO EXPECT THEM TO DIMINISH/DISSIPATE AFTER SUNSET. RADAR
SHOWS LIGHT SHOWERS...MOSTLY MOVING OFF THE COASTS OF MAINE AND NH
AND PASSING JUST EAST OF CAPE ANN.
NO CHANGES IN FORECAST THINKING. ADJUSTED TEMPS AND WINDS TOWARD
OBSERVED VALUES AND PROJECTED THE NEXT FEW HOURS USING A BLEND OF
THE GLAMP AND HRRR MODELS.
PREVIOUS DISCUSSION...
HIGH PRES RIDGE WILL BUILD OUT OF NY STATE ACROSS NEW ENGLAND
TONIGHT...BRINGING DIMINISHING WINDS. HOWEVER...APPEARS THERE WILL
BE JUST ENOUGH WIND THROUGH MOST OF THE NIGHT ESPECIALLY ACROSS
CENTRAL AND EASTERN AREAS TO ESCAPE A LONG FROST. MAY SEE PATCHY
FROST FOR AN HOUR OR TWO AFTER 06Z ACROSS THESE AREAS. BEST SHOT
OF PATCHY FROST WILL OCCUR ACROSS S NH/N CENTRAL AND NW MA...WHERE
THE GROWING SEASON HAS NOT BEGUN YET.
EXPECT OVERNIGHT LOWS IN THE MID TO UPPER 30S ACROSS THE NORMALLY
COLDER INLAND LOCATIONS...RANGING TO THE MID 40S ALONG THE
IMMEDIATE COAST.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
WEDNESDAY...
UPPER LEVEL PATTERN REMAINS PROGRESSIVE ACROSS THE LOWER 48...SO
EXPECT NEXT DISTURBANCE TO WORK OUT OF THE GREAT LAKES DURING WED.
WILL SEE CLOUDS INCREASE STEADILY DURING THE DAY WITH THE APPROACH
OF A WARM FRONT. SHOWERS WILL MOVE INTO THE CT VALLEY IN THE
AFTERNOON AND MOVE STEADILY E. MAY HAVE MARGINAL INSTABILITY...
WITH TOTAL TOTALS FROM 48 TO 50 MOVING ACROSS SOUTHERN AREAS.
HAVE MENTIONED ISOLD THUNDER THERE...BUT LOW CONFIDENCE ON THIS
ASPECT. TOTAL QFP WILL BE AROUND 0.25 INCHES...BUT CAN NOT RULE
OUT LOCALIZED SPOTTY DOWNPOURS.
AS WARM FRONT PASSES...S-SW WINDS WILL PICK UP WITH GUSTS UP TO
20-25 KT FROM AROUND 18Z INTO THE EVENING...HIGHEST ALONG THE S
COAST.
EXPECT HIGHS IN THE 60S...EXCEPT THE MID-UPPER 50S ALONG THE S
COAST.
WEDNESDAY NIGHT...
TRAILING COLD FRONT WILL STEADILY MOVE ACROSS THE REGION EARLY.
SHOWERS SHOULD PUSH E AFTER MIDNIGHT...EXITING THE CAPE AND
ISLANDS BY 10Z OR SO. WINDS WILL SHIFT TO W AND DIMINISH. WITH
CLOUDS LINGERING...EXPECT TEMPS TO ONLY FALL BACK TO THE MID 40S
TO LOWER 50S.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
BIG PICTURE...
UPPER TROUGH OVER NEW ENGLAND AND THE MARITIMES LATE WEEK AND
OVER THE WEEKEND. UPPER RIDGE BUILDS ON MONDAY-TUESDAY.
MODEL PREFERENCES...
MODEL MASS FIELDS THIS SIDE OF THE GREAT LAKES LOOK RATHER
SIMILAR THROUGH THE PERIOD. WE USED A BLEND OF THE LONG RANGE
HPC/GMOS TEMPS AND GFS/ECMWF SKY COVER. POP CONTOURS WERE HAND
DRAWN BASED ON OVERLAID QPF FIELDS.
THE DAILIES...
THURSDAY... COLD FRONT MOVES OFFSHORE EARLY. UPPER TROUGH AND COLD
POOL MOVE ACROSS DURING THE DAY. SOME DESTABILIZATION/CAA ALOFT/
OVER OUR AREA...BUT THE FOCUS OF THIS WILL TAKE PLACE OVER
VT/NH/MAINE. EXPECT DIURNAL CUMULUS BUT AIRMASS LOOKS TOO DRY FOR
SHOWERS. MIXING WILL BE DEEP...REACHING ABOVE 800 MB. WINDS IN
THIS LAYER ARE EXPECTED TO REACH 35 KNOTS...EVEN A FEW INDICATIONS
OF NEAR 40 KNOTS HIGH IN THE LAYER. SO WIND GUSTS ABOVE 30 KNOTS
ARE ALSO EXPECTED DURING THE AFTERNOON. CLOUDS AND WIND DIMINISH
IN THE EVENING. TEMPS ARE A BLEND OF MOS.
FRIDAY THROUGH SUNDAY... DRY THROUGH THE PERIOD AS HIGH PRESSURE
BUILDS SOUTH FROM NORTHERN QUEBEC. THE HIGH SHIFTS OFFSHORE DURING
SUNDAY. THERE MAY BE ADDITIONAL DIURNAL CUMULUS ESPECIALLY ON FRIDAY-
SATURDAY AND IN THIS RESPECT THE FORECAST MAY BE TOO OPTIMISTIC WITH
SUNSHINE. BUT THE AIRMASS LOOKS SUFFICIENTLY DRY TO LIMIT CLOUD
DEVELOPMENT. TEMPS ARE A BLEND OF LONG-RANGE MOS.
SUNDAY NIGHT-MONDAY-TUESDAY... BUILDING RIDGE ALOFT WILL WORK TO
KEEP THE WEATHER DRY. WARM ADVECTION WEST OF THE SURFACE HIGH WILL
BRING ISENTROPIC LIFT AND WORK TO INCREASE SKY COVER. CLOUDS OVER
THE MID ATLANTIC/OHIO VALLEY WILL GET CAUGHT UP IN THE RETURN FLOW
AND GET DRAWN NORTH. NOT A LOT OF CONFIDENCE IN THIS PART OF THE
FORECAST...BUT MOST OF THE FAVORABLE PARAMETERS FOR SHOWERS WILL
REMAIN TO OUR WEST OVER NY/PA THIS PERIOD. SOME SEMBLANCE OF A
WARM FRONT MOVES THROUGH LATER SUNDAY NIGHT/MONDAY...AND WE HAVE
INCLUDED CHANCE POPS DURING THIS PERIOD IN OUR WESTERN AND
NORTHERN ZONES. MORE SHOWERS APPROACH FROM THE WEST LATE
TUESDAY...AND SO WE HAVE CHANCE POPS ENTER FROM THE WEST TUESDAY
NIGHT. STAY TUNED FOR LATER FORECAST CYCLES AS THIS SETUP BECOMES
CLEARER.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH WEDNESDAY NIGHT/...
TONIGHT...HIGH CONFIDENCE. VFR WITH DIMINISHING WIND. DIMINISHING
SKY COVER BETWEEN 9 PM AND MIDNIGHT.
WEDNESDAY...MODERATE TO HIGH CONFIDENCE. VFR MOST OF THE DAY. MAY
SEE PATCHY MVFR CIGS/VSBYS MOVE INTO CT VALLEY LATE IN THE DAY.
SCT SHOWERS MOVE IN FROM W-E DURING THE DAY AS WARM FRONT
APPROACHES.
WEDNESDAY NIGHT...MODERATE CONFIDENCE. CIGS/VSBYS LOWERING TO MVFR
WITH POCKETS OF IFR CONDITIONS IN SCT-WIDESPREAD SHOWERS AND FOG.
S-SW WINDS MAY GUST TO 25 KT EARLY BEFORE WIND SHIFT. LOW
CONFIDENCE OF ISOLD THUNDER. CONDITIONS IMPROVE ACROSS WESTERN
AREAS AFTER MIDNIGHT ON W-NW WINDS.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK...THURSDAY THROUGH SUNDAY...
THURSDAY... AREAS OF IFR IN MORNING FOG...OTHERWISE VFR. VFR
LEVEL CLOUDS DEVELOP MIDDAY/AFTERNOON ESPECIALLY SOUTHERN
NH/NORTHERN MASS. WEST-NORTHWEST WINDS INCREASE DURING THE
MORNING...WITH GUSTS TO 35 KNOTS EXPECTED IN THE AFTERNOON AND
DIMINISHING IN THE EVENING.
FRIDAY THROUGH SUNDAY... VFR THROUGH THE PERIOD. LIGHTER WINDS
WITH POTENTIAL FOR MIDDAY/AFTERNOON SEABREEZES EACH DAY.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH WEDNESDAY NIGHT/...
HIGH CONFIDENCE THROUGH PERIOD.
EXPECT WINDS AND SEAS TO REMAIN BELOW SMALL CRAFT THROUGH
WEDNESDAY MORNING. S-SW WINDS WILL PICK UP...GUSTING TO 25 KT OVER
THE OPEN WATERS. SEAS WILL ALSO BUILD...UP TO 8 FT ON THE OUTER
WATERS. WINDS WILL SHIFT TO W AND GRADUALLY DIMINISH LATE WED AS
COLD FRONT PASSES. SEAS WILL REMAIN AOA 5 FT THROUGH WED NIGHT.
OUTLOOK...THURSDAY THROUGH SUNDAY...
THURSDAY...SEAS 5 TO 7 FEET ON THE OUTER WATERS AND RI/BID
SOUNDS...SO A SMALL CRAFT ADVISORY FOR SEAS WILL CONTINUE TO BE
NEEDED. WINDS OVER LAND WILL INCREASE TO 25-35 KNOTS MIDDAY AND
AFTERNOON. SOME OF THIS WIND MAY AFFECT THE NEARSHORE WATERS AND
REQUIRE A SMALL CRAFT HEADLINE AS WELL.
FRIDAY THROUGH SUNDAY... WINDS AND SEAS EXPECTED TO REMAIN BELOW
SMALL CRAFT CRITERIA MOST OF THE PERIOD. SEAS ON THE OUTER WATERS
MAY APPROACH 5 FEET ON SUNDAY.
&&
.FIRE WEATHER...
WEDNESDAY...EXPECT MINIMUM RH VALUES TO RANGE FROM THE MID 30S
ACROSS E MA TO 50-60 PERCENT ACROSS S COAST...CAPE COD AND THE
ISLANDS EARLY WED...THEN WILL INCREASE AS CLOUDS AND SHOWERS MOVE
IN. GREEN-UP ALSO CONTINUES...AS MUCH OF THE REGION REMAINS BELOW
NORMAL FOR TOTAL RAINFALL OVER THE LAST TWO MONTHS. S-SW WINDS
WILL BECOME GUSTY...UP TO 20-25 KT WED AFTERNOON AND NIGHT BUT
SHOULD SEE WIDESPREAD SHOWERS MOVING IN. NOT EXPECTING A LOT OF
RAINFALL LATE WED AND WED NIGHT...MAINLY AROUND 0.25 INCHES.
THE FORECASTED RAINFALL WILL BE OF SOME HELP TOWARDS THE BELOW
NORMAL RAINFALL CONDITIONS. HOWEVER...THE REGION REMAINS DRY
POSSIBLY CONDUCIVE TOWARDS FUTURE FIRE WEATHER POTENTIAL.
OUTLOOK...
MINIMUM RELATIVE HUMIDITY FOR THURSDAY AND FRIDAY IS EXPECTED AT
20 TO 30 PERCENT EACH DAY. WEST-NORTHWEST WINDS ON THURSDAY WILL
INCREASE BY MIDDAY WITH AFTERNOON GUSTS TO 30 KNOTS AND POSSIBLY
35 KNOTS. THESE CONDITIONS ON THURSDAY WILL NEED TO BE WATCHED.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 PM WEDNESDAY TO 2 AM EDT THURSDAY
FOR ANZ232.
SMALL CRAFT ADVISORY FROM 2 PM WEDNESDAY TO 8 AM EDT THURSDAY
FOR ANZ235-237-250-254>256.
SMALL CRAFT ADVISORY FROM 2 PM WEDNESDAY TO 6 AM EDT THURSDAY
FOR ANZ251.
&&
$$
SYNOPSIS...WTB/EVT
NEAR TERM...WTB/EVT/THOMPSON
SHORT TERM...EVT
LONG TERM...WTB
AVIATION...WTB/EVT/THOMPSON
MARINE...WTB/EVT
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
540 PM EDT TUE MAY 14 2013
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE SOUTHEAST COAST TONIGHT AND OUT TO
SEA INTO THURSDAY. A WARM FRONT IS FORECAST TO LIFT THROUGH OUR AREA
ON EARLY WEDNESDAY, FOLLOWED BY A COLD FRONT WEDNESDAY NIGHT. THIS
FRONT WILL SAG TO OUR SOUTH AND STALL FOR THE LATE WEEK PERIOD AND
INTO THE WEEKEND. THE FRONT MAY LIFT BACK NORTHWARD ACROSS THE AREA
AS A WARM FRONT EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
USED THE LATEST RAP AND HR3 TO MAKE SOME SOUTHWARD ADJUSTMENTS TO
MENTION OF PCPN AT ONSET EARLY OVERNIGHT. SO FAR AIRPORTS IN WRN
PA ARE OBSERVING TRACES. OTHERWISE TEMPS WERE TWEAKED SLIGHTLY
DOWNWARD BASED ON CURRENT TEMPS. MOST OTHER PARAMETERS AND GRIDS
DID NOT NEED MUCH CHANGE.
RAPIDLY THICKENING AND LOWERING CIGS ...THE BAND YOU SEE ON 19Z
SATELLITE IMAGERY FROM MICHIGAN TO W PTNS PA AND NYS. SCT LIGHT
SHOWERS EXPECTED...MOSTLY TRACE...AFTER MIDNIGHT AND MODELED IMO
PRETTY WELL BY THE 00Z/14 NSSL WRF AND NOW THE 18Z RAP...FLYING
SEWD 30-40 KT. LIGHT S WIND IN THE WAA PATTERN BEHIND THE
DEPARTING SFC HIGH OFF THE SE USA COAST.
50 50 BLENDED 12Z/14 NCEP MOS GUIDANCE FOR TEMPS/WINDS/DEWS.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
WEDNESDAY...THE 12Z GFS LOOKS LIKE MY IDEA OF A BEST MODEL SOLN OF
THE 12Z INTERNATIONAL SUITE. THE 12/14 GFS IMO HAS THE RIGHT IDEA
ABOUT STRONG CONVECTION AND PROBABLY STREAMING EAST SOUTHEAST FROM
SOUTHERN PA ACROSS S NJ AND OR THE DELMARVA LATE IN THE DAY WEDNESDAY.
SPC 1715Z SWODY2 ASSESSMENT MATCHES MY THINKING.
THE INCREASING BOUNDARY LAYER MOISTURE MAY BE OVERDONE BY THE MODELS,
THUS LIMITING INSTABILITY AND THE POTENTIAL FOR INITIATING CONVECTION.
THE 18Z GFS LAMP HAS GRIDDED LAMP TSTM PROBS IN W NYS AND NW PA BY
14Z.
MODEL REMNANTS OF AN EML NOW SPREADING EWD FROM THE MIDWEST THAT
SUPPORTS CONCERN FOR HAILERS....INCREASING THE 700-500MB LAPSE
RATES LATE IN THE DAY.
MORE THAN ADEQUATE BULK SHEAR FOR SVR WIND... AND SO THE QUESTION
BECOMES...IS THERE ENOUGH MOISTURE TO SUPPORT TSTM GENERATION. 12Z/14
GFS ML CAPE IS ONLY 600J LATER IN THE DAY AND SO DID NOT WORD HAIL
OR GUSTY WINDS IN THE ZONE PRODUCTS.
OTRW TEMPS/WINDS/DEWS ARE 50 50 BLENDED 12Z/14 NCEP MOS GUIDANCE
WITH A LEAN TO A WARMER TEMP SOLN SINCE MOST OF THE DAY SHOULD
BE RAINFREE.
CONFIDENCE ON POPS IS BELOW AVG AND I MAY BE OVER FCST THE CHC OF
A SHOWER OR TSTM WED AFTN.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
THE PRE-FRONTAL SURFACE TROUGH AND ANY ASSOCIATED CONVECTION SHOULD
BE PROGRESSING THROUGH THE AREA DURING THE EARLY EVENING TIME
WEDNESDAY. ONCE THE TROUGH MOVES THROUGH AND THE SUN GOES DOWN,
ANY CONVECTION SHOULD DIMINISH. THE ACTUAL COLD FRONT IS NOT
EXPECTED TO MOVE THROUGH THE AREA UNTIL WEDNESDAY NIGHT. THERE
STILL COULD BE A FEW SHOWERS AROUND UNTIL THE FRONT ACTUALLY MOVES
THROUGH, BUT ANY THUNDERSTORM ACTIVITY SHOULD HAVE ENDED BY THE
TIME THE FRONT APPROACHES.
THE AFOREMENTIONED COLD FRONT WILL SAG TO OUR SOUTH THURSDAY INTO
FRIDAY, WHILE THE PARENT LOW WILL SPIN THROUGH NEW ENGLAND AND
INTO THE CANADIAN MARITIMES. THIS WILL KEEP A STEADY WEST TO
NORTHWEST FLOW ACROSS THE AREA. EVEN THOUGH A WEAK SURFACE TROUGH
IS FORECAST TO CROSS THE AREA ON THURSDAY, MOST OF THE AREA SHOULD
REMAIN DRY THURSDAY AND FRIDAY. THE EXCEPTION TO THIS WILL BE
ACROSS THE SOUTHERN THIRD OF THE AREA, WHICH WOULD BE CLOSE TO THE
OLD COLD FRONT AS IT SLOWLY SAGS TO OUR SOUTH, BEFORE STALLING.
THERE MAY BE ENOUGH MOISTURE AND LIFT TO CREATE A FEW SCATTERED
SHOWERS/THUNDERSTORMS ACROSS SOUTHERN NEW JERSEY AND THE DELMARVA.
AS WE MOVE INTO THE WEEKEND, THE LOW TO OUR NORTHEAST WILL SLIDE OUT
TO SEA, ALLOWING FOR HIGH PRESSURE TO BUILD ACROSS THE NORTHEAST.
THIS HIGH IS EXPECTED TO PUSH OFF THE NEW ENGLAND COAST AND TO
OUR EAST THROUGH THE WEEKEND. THIS WILL PUT OUR AREA INTO AN
EASTERLY/SOUTHEASTERLY FLOW FOR MUCH OF THE WEEKEND, WHICH COULD
HELP KEEP OUR TEMPERATURES FRONT RISING VERY MUCH. IT MAY ALSO
KEEP SOME CLOUD COVER ACROSS THE AREA, AND WITH AN INCREASE IN
MOISTURE, ANY ADDITIONAL LIFT COULD LEAD TO SOME PRECIPITATION.
FOR NOW WE ONLY KEEP CHANCE/SLIGHT CHANCE POPS THROUGH THE
WEEKEND.
THE FRONT THAT STALLS TO OUR SOUTH IS EXPECTED TO BEGIN LIFTING
BACK NORTHWARD AS A WARM FRONT BY LATE SUNDAY INTO MONDAY. THIS
COULD LEAD TO SOME SHOWER ACTIVITY SUNDAY NIGHT INTO MONDAY. THEN
WE WAIT AND SEE WHAT HAPPENS WITH THE NEXT SYSTEM AS IT MOVES OUT
OF THE CENTRAL/NORTHERN PLAINS AND THROUGH THE GREAT LAKES.
GFS/ECMWF DIFFER ON HOW FAST THEY MOVE THE SYSTEM. IT`S POSSIBLE
IT COULD GET HERE AS EARLY AS WEDNESDAY, BUT WE WILL SEE HOW
MODELS HANDLE IT OVER THE NEXT FEW DAYS.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR CIGS AOA 7000 FT DEVELOPING FM WNW TO ESE WITH SCT
SPRINKLES OR LIGHT .02/HR SHOWERS STREAMING SEWD 30-40 KT AFTER
04Z. LIGHT SOUTH SFC WIND.
WEDNESDAY...VFR SCT-BKN CLOUDS AOA 5000 FT WITH ONLY A SMALL
CHANCE OF A LEFTOVER SHOWER POSSIBLE IN THE MORNING BUT A BAND OF
SCT-BKN SHOWERS AND ISO STRONG TSTMS EXPECTED LATE IN THE DAY...
PROBABLY MOVING ESEWD THRU SE PA NEAR KPHL. SSW WIND GUSTS 15 KT
IN THE AFTN. STRONGER WLY GUST TO 35 KT `POSSIBLE` IN A LATE DAY
TSTM VCNTY KPHL. CONFIDENCE ON THUNDERSTORM INITIATION WED AFTN IN
SRN PA IS BELOW AVG DUE TO MOST MODELS NOT FCSTG MUCH IF ANY
SHOWER ACTIVITY.
OUTLOOK...
WEDNESDAY NIGHT...MOSTLY VFR CONDITIONS. MVFR POSSIBLE WITH ANY
SHOWERS/THUNDERSTORMS EARLY.
THURSDAY-FRIDAY...MOSTLY VFR CONDITIONS.
SATURDAY-SUNDAY...MAINLY VFR CONDITIONS...POSSIBLE PERIODS OF MVFR
SATURDAY NIGHT. SHOWERS ALSO POSSIBLE
&&
.MARINE...
HIGH PRESSURE WILL MOVE OVER THE SERN CONUS TODAY AND THEN FURTHER
EWD OVER THE SERN COASTAL WATERS TONIGHT. AS A RESULT THE WIND
AND SEAS ARE EXPECTED TO REMAIN BELOW SCA CRITERIA THRU THE NEAR
PERIOD.
WEDNESDAY...GUIDANCE INDICATES OUR COASTAL WATERS WILL REACH SCA
WIND GUSTS DURING THE DAYTIME WEDNESDAY WITH SEAS BUILDING TO 5
FT ON THE ATLC WATERS DURING THE AFTN GENERATED BY THE SLY FLOW
AHEAD OF AN APPROACHING WFRONT. FOR LOWER DE BAY THERE MAY BE A
PERIOD OF SCA WIND GUSTS WEDNESDAY BUT CONFIDENCE WAS NOT HIGH
ENOUGH AT THIS TIME TO INCLUDE THIS AS A HEADLINE.
AM STARTING THE SCA A BIT SOONER ON THE ATLC WATERS WEDNESDAY...
AROUND 12Z. WILL LEAVE IT TO THE MID SHIFT TO ISSUE FOR DE BAY.
OUTLOOK...
THE SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT THROUGH WEDNESDAY
NIGHT AS SEAS WILL LIKELY REMAIN ABOVE 5 FEET AND WINDS COULD GUST
AROUND 25 KNOTS EARLY. HOWEVER, AFTER THE COLD FRONT MOVES
THROUGH, WINDS ARE EXPECTED TO DROP BELOW ADVISORY LEVELS THROUGH
FRIDAY NIGHT. SEAS MAY REMAIN AROUND 5 FEET INTO EARLY THURSDAY,
BUT NOT CONFIDENT ENOUGH TO EXTEND THE ADVISORY OUT ANOTHER DAY
YET. ONCE SEAS DROP BELOW 5 FEET, THEY WILL REMAIN SO THROUGH
FRIDAY NIGHT.
AS WE MOVE INTO THE WEEKEND, HIGH PRESSURE BUILDS TO OUR
NORTH/NORTHEAST, WHICH WILL PRESENT AN EAST/SOUTHEAST FETCH ACROSS
THE WATERS. WINDS COULD BEGIN APPROACHING SMALL CRAFT CONDITIONS
STARTING SATURDAY NIGHT AND SEAS COULD BEGIN INCREASING AS WELL
CLOSE TO 5 FEET BY SUNDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 AM WEDNESDAY TO 8 AM EDT THURSDAY
FOR ANZ450>455.
&&
$$
SYNOPSIS...ROBERTSON
NEAR TERM...DRAG/GIGI
SHORT TERM...DRAG
LONG TERM...ROBERTSON
AVIATION...DRAG/ROBERTSON
MARINE...DRAG/ROBERTSON
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1233 PM CDT TUE MAY 14 2013
...UPDATED AVIATION AND PUBLIC DISCUSSION...
.UPDATE...
ISSUED AT 1233 PM CDT TUE MAY 14 2013
HOT CONDITIONS CONTINUE TO STREAM INTO WESTERN AND NORTHWEST IOWA...
ALREADY BREAKING RECORDS IN SOME PORTIONS OF THE STATE TODAY. WINDS
GENERALLY FULLY MIXED NOW SO WARMING OVER THESE AREAS WILL SLOW...
BUT STILL MANAGE TO PUSH A FEW SPOTS IN OUR WEST TO NORTHWEST
FORECAST AREA IN EXCESS OF 100F THIS AFTERNOON. HIGHS ACROSS CENTRAL
AND SOUTHEAST LOOK REASONABLE...AND HAVE RAISED HIGHS NORTH AND WEST
PORTIONS FOR TODAY. DEW POINTS HAVE RISEN MOST AREAS THROUGH THE
MORNING HOURS AND HAVE MADE ADJUSTMENTS...SOME POOLING TAKING PLACE
OVER CENTRAL IOWA NOW...WITH AREAS SEEING MIXING DEW POINTS RAPIDLY
TANKING BACK INTO THE 40S.
.SHORT TERM.../TODAY/...
ISSUED AT 407 AM CDT TUE MAY 14 2013
FORECAST CHALLENGE TODAY IS WITH RECORD OR
NEAR RECORD HIGH MAX TEMPS...DEW POINTS AND WINDS. MODELS STILL
INITIALIZING TOO MOIST WITH THE RAP CONTINUING TO BE THE DRY
SOLUTION TODAY. RAP ALSO HAS THE BETTER HANDLE ON THE TEMPS
TODAY...SO LEANED CLOSER TO THE RAP SOLUTION.
WINDS WILL INCREASE LATE THIS MORNING AND CONTINUE TO MIX DURING THE
AFTERNOON WITH RAP SHOWING THE BEST DRY ADIABATIC SOUNDING. MIXING
TO 850MB SHOULD TAP INTO THE +25C TEMPERATURES ADVECTING INTO
WESTERN TO NORTHERN IOWA BY THIS AFTERNOON. NAM/GFS/ECMWF SOUNDINGS
ARE NOT AS AGGRESSIVE WITH THE MIXING TODAY...AND POSSIBLY ONE
REASON THESE MODELS OVERDOING THE DEW POINTS. TEMPS OVERNIGHT
REMAINING IN THE UPPER 50S/LOWER 60S ACROSS MUCH OF THE FORECAST
AREA...AND WITH THE NORTHWEST FORECAST AREA RISING 2-4 DEGREES
WARMER MONDAY THAN ANTICIPATED...CONFIDENT ENOUGH TO TWEAK MAX TEMPS
UP SLIGHTLY OVER THE WEST AND NORTH. WENT ROUGHLY 3 TO 5 DEGREES
ABOVE THE WARMEST GUIDANCE TODAY. WITH THE DRIER DEW POINTS AND RH
VALUES COMBINED WITH THE GUSTY SOUTHWEST WINDS...DECIDED TO UPGRADE
TO A RED FLAG WARNING. SEE FIRE WEATHER DISCUSSION FOR FURTHER
DETAILS.
.LONG TERM.../TONIGHT THROUGH MONDAY/...
ISSUED AT 400 AM CDT TUE MAY 14 2013
THE FRONTAL BOUNDARY WILL DROP SLOWLY SOUTH THROUGH THE STATE
OVERNIGHT BEFORE STALLING IN THE ZONAL FLOW JUST SOUTH INTO
MISSOURI ON WEDNESDAY. MOISTURE REMAINS QUITE LIMITED WITH THE
SYSTEM. ANY SHOWERS AND THUNDERSTORMS THAT DO FORM WILL BE
EXTREMELY HIGH BASED AND ABOVE THE PRIMARY AREA OF FORCING. THIS
COMBINED WITH THE LACK OF ASSOCIATED MOISTURE WILL KEEP ANY
ACTIVITY QUITE SPARSE. BROAD AREA OF LOW PRESSURE WILL BECOME
REFOCUSED OVER WYOMING AND THE WESTERN DAKOTAS THURSDAY INTO
FRIDAY. THIS WILL HELP DRIVE THE FRONTAL BOUNDARY BACK NORTH AS A
WARM FRONT. PRECIPITATION CHANCES WILL CONTINUE MAINLY OVER THE
SOUTH WEDNESDAY BEFORE SPREADING BACK NORTH WITH THE FRONTAL
PASSAGE THROUGH THE END OF THE WEEK.
HAVE MAINTAINED THUNDERSTORM CHANCES ON SATURDAY THOUGH THE SIGNS
BEGINNING TO POINT TO THE STATE BEING IN THE WARM SECTOR WITH THE
WARM FRONT MOVING NORTH OF THE STATE. WARM AIR ALOFT WOULD LEAVE A
FAIR AMOUNT OF CONVECTIVE INHIBITION TO OVERCOME ON SATURDAY.
BETTER CHANCE FOR THUNDERSTORMS AND POSSIBLY SEVERE WEATHER WOULD
BE SUNDAY AS A THE UPPER LEVEL RIDGE BEGINS TO BE SHOVED EAST BY
AN UPPER LEVEL SYSTEM ENTERING THE NORTHWESTERN CONUS. THIS WILL
INCREASE THE SOUTHWEST FLOW INTO THE STATE EARLY SUNDAY WITH A
COLD FRONT ARRIVING LATER IN THE DAY. CERTAINLY A FAVORABLE SETUP
FOR SURFACE BASED CONVECTION WITH THE PRIMARY THREATS OF WIND AND
HAIL WITH THE TRIPLE POINT WELL TO THE NORTH...BUT IT IS STILL
SEVERAL DAYS AWAY.
TEMPERATURES THROUGH THE PERIOD WILL BE SEASONAL TO ABOVE NORMAL.
POSSIBLY CLOUD COVER ON WEDNESDAY AND THURSDAY WILL HAVE AN IMPACT
ON TEMPERATURES. THURSDAY ESPECIALLY WILL BE COOLER THAN THE NORTH
DUE TO PRECIPITATION AND CLOUDS. LIKELY A RETURN TO THE 80S ON
SATURDAY WITH DEWPOINTS POSSIBLY RISING INTO THE 60S.
&&
.AVIATION...14/18Z
ISSUED AT 1233 PM CDT TUE MAY 14 2013
MAIN CONCERNS THIS PERIOD REMAIN WINDS AND POTENTIAL FOR SOME
THUNDER FOR THE LATE AFTERNOON AND OVERNIGHT HOURS. WINDS CONTINUE
STRONG NORTHWEST AND NORTH AREAS WHERE MIXED LAYER RAPIDLY REACHING
FULL DEPTH EARLY THIS AFTERNOON. WILL CONTINUE TO SEE STRONG WINDS
THROUGH 23Z DIMINISHING THEREAFTER. WITH MOISTURE POOLING OVER
PORTIONS OF CENTRAL IOWA...SOME CONCERNS OF INSTABILITY THOUGH NO
FOCUSING MECHANISM UNTIL BOUNDARY APPROACHES THIS EVENING. WITH
BOUNDARY SOUTH OF AREA OVERNIGHT...SOME RETURN FLOW ALOFT SHOWS MORE
PROMISE TO INITIATE SCATTERED CONVECTION OVER THE SOUTH. HAVE
INCLUDED VCSH FOR KDSM AND KOTM...BUT OTHERWISE WILL KEEP DRY FOR
THIS PERIOD UNTIL ANY BETTER ORGANIZATION SHOWS ITS HAND.
&&
.FIRE WEATHER...
UPDATE AT 1233 PM TUE...NO CHANGES TO GOING CONDITIONS AND AREAL
EXTENT FOR THE REMAINDER OF THIS AFTERNOON.
STRONGEST WIND GUSTS AND LOWEST RELATIVE HUMIDITY VALUES ARE
EXPECTED BETWEEN NOON AND 7PM TODAY OVER WESTERN AND NORTHERN
PORTIONS OF THE FORECAST AREA. RH VALUES RANGING FROM 17 TO 22
PERCENT AND SUSTAINED WINDS AROUND 25 MPH OR SLIGHTLY HIGHER ARE
LIKELY DURING THE AFTERNOON. GFDI VALUES RANGES IN THE MODERATE TO
HIGH CATEGORY PAST NOON TODAY AND MAY BARELY BUMP INTO THE EXTREME
CATEGORY FOR A FEW HOURS BETWEEN 2PM AND 5PM THIS AFTERNOON.
MIXING HEIGHT LOOKS TO BE IN THE 3000 TO 3500 FEET LATE THIS
MORNING AND INTO THE AFTERNOON...WITH A SHORT STINT OF MIXING
HIGHER. REPLACED THE FIRE WEATHER WATCH WITH A RED FLAG WARNING
DUE TO THE VERY LOW RH VALUES...STRONG WINDS...AND FUELS NOT
ENTIRELY GREEN YET.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
ADAIR-ADAMS-AUDUBON-BOONE-CALHOUN-CARROLL-CASS-CERRO GORDO-
CRAWFORD-DALLAS-EMMET-FRANKLIN-GREENE-GUTHRIE-HAMILTON-HANCOCK-
HUMBOLDT-KOSSUTH-PALO ALTO-POCAHONTAS-SAC-WEBSTER-WINNEBAGO-
WORTH-WRIGHT.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...DONAVON
AVIATION...REV
FIRE WEATHER...PODRAZIK
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
355 PM CDT TUE MAY 14 2013
...UPDATED LONG TERM SECTION...
.SYNOPSIS...
ISSUED AT 931 AM CDT TUE MAY 14 2013
THE 14.12Z 250 HPA RAOB MAP SHOWED TWO JETS ACROSS NORTH AMERICA. THE
POLAR JET WAS LOCATED ACROSS THE NORTHERN PORTIONS OF UNITED STATES
AND INTO CANADA. THE STRONGEST WINDS WERE LOCATED FROM NOVA SCOTIA AND
INTO THE CANADIAN MARITIMES WITH MAGNITUDES AROUND 180 KT. NEXT, THE
SUBTROPICAL JET WAS LOCATED FARTHER SOUTH WITH HIGHEST MAGNITUDES AROUND
90 KT ACROSS FLORIDA. CLOSER TO KANSAS, FLOW WAS QUITE WEAK AT 15 KT. AT
500 HPA, A TROF WAS MOVING ONSHORE ACROSS CENTRAL CALIFORNIA. DAMPENING
SHORTWAVE RIDGING WAS DOWNSTREAM OF THIS FEATURE ACROSS THE 4 CORNERS
REGION. A WEAK LOW WAS LOCATED ACROSS PORTIONS OF MEXICO. A SHORTWAVE
TROF WAS MOVING ACROSS THE CENTRAL CANADIAN PRAIRIES. AN ELONGATED TROF
WAS LOCATED ACROSS THE NE U.S. AND SE CANADA. AT 700 HPA, TEMPERATURES
ACROSS SW KANSAS WERE FAIRLY WARM (10 DEG C). AT 850 HPA, 25 DEG C AT
KDDC WAS SLIGHTLY UNDER THE +2 STANDARD DEVIATION STATISTICAL MARK.
AT THE SFC, A COLD FRONT WAS LOCATED ACROSS THE NORTHERN PLAINS AND
A SURFACE LEE TROF WAS LOCATED ACROSS FAR WESTERN KANSAS.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 252 PM CDT TUE MAY 14 2013
TONIGHT:
EARLY AFTERNOON VISIBLE SATELLITE IMAGERY SHOWS A FIELD OF CUMULUS HUMILIS
CLOUDS ACROSS NORTHWEST KANSAS. THESE CLOUDS ARE IN ASSOCIATION WITH
A LEE SURFACE TROF ACROSS NORTHWEST KANSAS AND WEAK INSTABILITY. RAP
AND HRRR KEEPS THIS ACTIVITY NORTHWEST OF THE FORECAST AREA OF RESPONSIBILITY
THROUGH TONIGHT. I HAVE 14 PERCENT PRECIPITATION PROBABILITIES IN THE
GRIDS THROUGH EARLY EVENING ACROSS WEST CENTRAL KANSAS. OTHERWISE, TONIGHT
WILL BE CLEAR AND PRECIPITATION FREE. LEE TROUGHING WILL CONTINUE THROUGH
THE OVERNIGHT PERIOD. SOUTHERLY WINDS IN ASSOCIATION WITH THIS FEATURE
WILL CONTINUE OVERNIGHT AS WELL. THESE WINDS WILL KEEP TEMPERATURES
MILD WITH LOWS IN THE UPPER 50S AND LOWER 60S DEG F.
TOMORROW:
ON WEDNESDAY, A LEE INDUCED LOW/TROF ACROSS SOUTHEASTERN COLORADO WILL DEEPEN
THROUGH THE AFTERNOON. THIS WILL CAUSE A WARM FRONT TO LIFT NORTHWARD
ACROSS PORTIONS OF WESTERN KANSAS. HIGHS TOMORROW IN THE WARM SECTOR
WILL BE WARM TO HOT AGAIN WITH HIGHS IN THE 86-91 DEG F RANGE. RAMPED
UP POPS IN THE AFTERNOON ACROSS THE EASTERN PORTIONS OF THE FORECAST
AREA OF RESPONSIBILITY. THERE IS SOME UNCERTAINTY IN WHERE CONVECTION
WILL DEVELOP ALONG THE FRONT AS MODELS DIFFER WITH THE FRONT POSITION.
12Z NAM DEVELOPS THUNDERSTORMS FROM LIBERAL TO HAYS, WHILE 12Z GFS KEEPS
PRECIPITATION MAINLY EAST OF HIGHWAY 183. THE WRF-NMM ECHOES THE NAM
SOLUTION, WHERE THE WRF-ARW KEEPS THE REGION DRY. DUE TO THE UNCERTAINTY,
WILL LIMIT PRECIPITATION PROBABILITIES IN THE SLIGHT CHANCE CATEGORY.
IF THE NAM SOLUTION IS CORRECT WITH MOISTURE, MLCAPE LOOKS TO BE AROUND
1500-3000 J/KG, MAINLY ACROSS SC KANSAS. 0-6 KM BULK SHEAR IS ON THE
WEAKER SIDE AT 30-35 KT. UPPER LEVEL WIND SHEAR IS VERY WEAK AT 15-30
KT. LCL`S WILL BE FAIRLY HIGH AS WELL. PUTTING THIS ALL TOGETHER, THE
OVERALL THREAT FOR HIGH END SEVERE WEATHER IS VERY LOW. THE MAIN THREAT
TOMORROW IS MARGINAL HAIL SIZE PERHAPS UP TO QUARTERS AND 50-60 MPH
OUTFLOW FROM THUNDERSTORMS.
LASTLY, LESS FIRE WEATHER CONCERNS ARE EXPECTED TOMORROW AFTERNOON AS
SLIGHTLY HIGHER DEWPOINTS AND RESULTANT HIGHER RELATIVE HUMIDITIES ARE
EXPECTED.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 354 PM CDT TUE MAY 14 2013
PRECIPITATION CHANCES, SEVERITY, AND COVERAGE WILL BE CHALLENGES IN
THE FORECAST LATE WEEK INTO THE WEEKEND...ALONG WITH AFTERNOON
TEMPERATURES WITH DRYLINE POSITION UNCERTAINTY.
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT:
A LOW AMPLITUDE SHORTWAVE TROUGH (CURRENTLY SEEN ON WATER VAPOR
SPINNING ACROSS CENTRAL CALIFORNIA) WILL BE MOVING TOWARD THE
CENTRAL HIGH PLAINS DURING THIS TIME FRAME. A WEAK FRONT MOVING
INTO EAST-CENTRAL COLORADO AND WEST-CENTRAL KANSAS WILL BE THE FOCUS
FOR THUNDERSTORMS LATE AFTERNOON WEDNESDAY...BUT THIS FRONT WILL
DISSOLVE BY WEDNESDAY NIGHT. A SMALL...LOOSELY ORGANIZED AREA OF
CONVECTION AHEAD OF THE APPROACHING WAVE MAY HOLD TOGETHER AS IT
APPROACHES FAR WEST-CENTRAL KANSAS...BUT CONFIDENCE IN THIS IS VERY
LOW AND ONLY SLIGHT CHANCE POPS ARE WARRANTED AT THIS TIME. ON
THURSDAY...THERE IS A LOT OF DISAGREEMENT ON THE 850MB
THERMODYNAMICS/MOISTURE BETWEEN THE NCEP MODELS AND THE ECMWF MODEL.
THE GFS AND NAM SHOW COPIOUS AMOUNTS OF MOISTURE AND NEAR-SATURATED
RH AT 850MB THROUGH 18Z THURSDAY WHICH IS AFFECTING THE BOUNDARY
LAYER TEMPERATURES TO THE POINT THAT THE NCEP MODELS KEEP
TEMPERATURES IN THE 70S FOR MUCH OF THE DAY. THE NCEP MODELS TEND TO
BE A BIT TOO AGGRESSIVE IN HOLDING ONTO STRATUS TOO LONG SO THE
OFFICIAL FORECAST FOR HIGHS THURSDAY WILL REFLECT MORE CLOSELY THE
ECMWF MODEL.
A DRYLINE WILL NO DOUBT BE A PREVAILING FEATURE, HOWEVER, WHICH
SHOULD FOCUS A FEW ISOLATED STORMS BY LATE AFTERNOON/EARLY
EVENING...ESPECIALLY SINCE THE AFOREMENTIONED LOW AMPLITUDE
SHORTWAVE TROUGH WILL BE PASSING JUST TO THE NORTH AIDING IN SOME
SLIGHT MID LEVEL COOLING AND OVERALL SLIGHT ENHANCEMENT OF DEEP
TROPOSPHERIC UPWARD VERTICAL MOTION. MID LEVEL FLOW AT THE BASE OF
THIS TROUGH AXIS OF 25 TO 35 KNOTS (500MB) ACROSS WESTERN KANSAS
WILL PROVIDE THE NECESSARY SHEAR ALONG WITH SOUTH-SOUTHEAST BOUNDARY
LAYER FLOW FOR SUPERCELL STORMS (ALONG WITH THE UPPER 50S TO NEAR 60
DEWPOINTS AT THE SURFACE). ANY THUNDERSTORMS LATE THURSDAY/THURSDAY
EVENING SHOULD DISSOLVE AFTER SUNSET AS INSOLATION GOES AWAY AND THE
SHORTWAVE TROUGH EXITS THE CENTRAL PLAINS.
FRIDAY AND SATURDAY:
A MUCH MORE IMPRESSIVE PACIFIC JET WILL ENTER THE SOUTHWEST/GREAT
BASIN REGION DURING THIS TIME FRAME...ENTERING THE ROCKIES AND
WESTERN PLAINS SATURDAY. THE DRYLINE WILL BE THE FOCUS FOR
THUNDERSTORMS BOTH OF THESE DAYS...BUT SATURDAY WILL BE THE BETTER
DAY OF THE TWO FOR MORE ORGANIZED SUPERCELL STORMS GIVEN THE GREATER
LOW LEVEL CONVERGENCE EXPECTED ALONG THE DRYLINE NEAR AND JUST SOUTH
OF THE SURFACE LOW. WILL HAVE CHANCE POPS NORTH OF A DIGHTON TO
LACROSSE LINE WHERE THE FORECAST SURFACE LOW WILL BE PER THE ECMWF
MODEL. SOUTH AND SOUTHWEST OF THE SURFACE LOW...HOT TEMPERATURES
WILL BE FOUND OVER A LARGER AREA THAN PREVIOUS DAYS WITH SOME UPPER
90S EVEN POSSIBLE.
SUNDAY AND BEYOND:
THE INITIAL JET STREAK WILL LIFT NORTH INTO THE NORTHERN PLAINS
LEADING TO THE FORMATION OF AN UPPER LOW...HOWEVER AN ENERGETIC JET
WILL STILL REMAIN ACROSS THE GREAT BASIN INTO THE CENTRAL ROCKIES
WHICH COULD LEAD TO DEVELOPMENT OF A SECONDARY LOW LATE SUNDAY INTO
MONDAY. SOME SLIGHT CHANCE POPS WERE INCLUDED THROUGH THE ALLBLEND
GUIDANCE ON SUNDAY AND MONDAY GIVEN THE PROSPECTS OF SOME POTENTIAL
POST-FRONTAL CONVECTION ROLLING EAST OFF THE EASTERN COLORADO
TERRAIN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1200 PM CDT TUE MAY 14 2013
VFR CIGS EXPECTED THROUGH PD. SOUTHWESTERLY WINDS 18-23 KT WILL CONTINUE
THIS AFTERNOON AND EVENTUALLY BACK SOUTHERLY 10-15 KT BY DUSK.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 60 89 60 86 / 0 20 20 10
GCK 58 92 59 88 / 10 10 10 20
EHA 56 91 58 92 / 0 10 10 20
LBL 57 92 60 92 / 0 10 10 10
HYS 59 90 60 83 / 10 20 20 10
P28 63 86 63 84 / 0 20 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR KSZ043>045-
062>064-075>078-084>088.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...SUGDEN
LONG TERM...UMSCHEID
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
252 PM CDT TUE MAY 14 2013
...UPDATE TO SHORT TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 931 AM CDT TUE MAY 14 2013
THE 14.12Z 250 HPA RAOB MAP SHOWED TWO JETS ACROSS NORTH AMERICA. THE
POLAR JET WAS LOCATED ACROSS THE NORTHERN PORTIONS OF UNITED STATES
AND INTO CANADA. THE STRONGEST WINDS WERE LOCATED FROM NOVA SCOTIA AND
INTO THE CANADIAN MARITIMES WITH MAGNITUDES AROUND 180 KT. NEXT, THE
SUBTROPICAL JET WAS LOCATED FARTHER SOUTH WITH HIGHEST MAGNITUDES AROUND
90 KT ACROSS FLORIDA. CLOSER TO KANSAS, FLOW WAS QUITE WEAK AT 15 KT. AT
500 HPA, A TROF WAS MOVING ONSHORE ACROSS CENTRAL CALIFORNIA. DAMPENING
SHORTWAVE RIDGING WAS DOWNSTREAM OF THIS FEATURE ACROSS THE 4 CORNERS
REGION. A WEAK LOW WAS LOCATED ACROSS PORTIONS OF MEXICO. A SHORTWAVE
TROF WAS MOVING ACROSS THE CENTRAL CANADIAN PRAIRIES. AN ELONGATED TROF
WAS LOCATED ACROSS THE NE U.S. AND SE CANADA. AT 700 HPA, TEMPERATURES
ACROSS SW KANSAS WERE FAIRLY WARM (10 DEG C). AT 850 HPA, 25 DEG C AT
KDDC WAS SLIGHTLY UNDER THE +2 STANDARD DEVIATION STATISTICAL MARK.
AT THE SFC, A COLD FRONT WAS LOCATED ACROSS THE NORTHERN PLAINS AND
A SURFACE LEE TROF WAS LOCATED ACROSS FAR WESTERN KANSAS.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 252 PM CDT TUE MAY 14 2013
TONIGHT:
EARLY AFTERNOON VISIBLE SATELLITE IMAGERY SHOWS A FIELD OF CUMULUS HUMILIS
CLOUDS ACROSS NORTHWEST KANSAS. THESE CLOUDS ARE IN ASSOCIATION WITH
A LEE SURFACE TROF ACROSS NORTHWEST KANSAS AND WEAK INSTABILITY. RAP
AND HRRR KEEPS THIS ACTIVITY NORTHWEST OF THE FORECAST AREA OF RESPONSIBILITY
THROUGH TONIGHT. I HAVE 14 PERCENT PRECIPITATION PROBABILITIES IN THE
GRIDS THROUGH EARLY EVENING ACROSS WEST CENTRAL KANSAS. OTHERWISE, TONIGHT
WILL BE CLEAR AND PRECIPITATION FREE. LEE TROUGHING WILL CONTINUE THROUGH
THE OVERNIGHT PERIOD. SOUTHERLY WINDS IN ASSOCIATION WITH THIS FEATURE
WILL CONTINUE OVERNIGHT AS WELL. THESE WINDS WILL KEEP TEMPERATURES
MILD WITH LOWS IN THE UPPER 50S AND LOWER 60S DEG F.
TOMORROW:
ON WEDNESDAY, A LEE INDUCED LOW/TROF ACROSS SOUTHEASTERN COLORADO WILL DEEPEN
THROUGH THE AFTERNOON. THIS WILL CAUSE A WARM FRONT TO LIFT NORTHWARD
ACROSS PORTIONS OF WESTERN KANSAS. HIGHS TOMORROW IN THE WARM SECTOR
WILL BE WARM TO HOT AGAIN WITH HIGHS IN THE 86-91 DEG F RANGE. RAMPED
UP POPS IN THE AFTERNOON ACROSS THE EASTERN PORTIONS OF THE FORECAST
AREA OF RESPONSIBILITY. THERE IS SOME UNCERTAINTY IN WHERE CONVECTION
WILL DEVELOP ALONG THE FRONT AS MODELS DIFFER WITH THE FRONT POSITION.
12Z NAM DEVELOPS THUNDERSTORMS FROM LIBERAL TO HAYS, WHILE 12Z GFS KEEPS
PRECIPITATION MAINLY EAST OF HIGHWAY 183. THE WRF-NMM ECHOES THE NAM
SOLUTION, WHERE THE WRF-ARW KEEPS THE REGION DRY. DUE TO THE UNCERTAINTY,
WILL LIMIT PRECIPITATION PROBABILITIES IN THE SLIGHT CHANCE CATEGORY.
IF THE NAM SOLUTION IS CORRECT WITH MOISTURE, MLCAPE LOOKS TO BE AROUND
1500-3000 J/KG, MAINLY ACROSS SC KANSAS. 0-6 KM BULK SHEAR IS ON THE
WEAKER SIDE AT 30-35 KT. UPPER LEVEL WIND SHEAR IS VERY WEAK AT 15-30
KT. LCL`S WILL BE FAIRLY HIGH AS WELL. PUTTING THIS ALL TOGETHER, THE
OVERALL THREAT FOR HIGH END SEVERE WEATHER IS VERY LOW. THE MAIN THREAT
TOMORROW IS MARGINAL HAIL SIZE PERHAPS UP TO QUARTERS AND 50-60 MPH
OUTFLOW FROM THUNDERSTORMS.
LASTLY, LESS FIRE WEATHER CONCERNS ARE EXPECTED TOMORROW AFTERNOON AS
SLIGHTLY HIGHER DEWPOINTS AND RESULTANT HIGHER RELATIVE HUMIDITIES ARE
EXPECTED.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 342 AM CDT TUE MAY 14 2013
.THROUGH FRIDAY...
AN ACTIVE WEATHER PATTERN IS FORECAST FOR THE REMAINDER OF THE
WEEK INTO THE WEEKEND AS A FEW DISTURBANCES MOVE THROUGH THE PLAINS.
AN UPPER LEVEL LOW WILL BE MOVING ACROSS KANSAS AS THE LONG TERM
PERIOD BEGINS ON WEDNESDAY WITH A WEAK UPPER LEVEL SHORTWAVE MOVING
ACROSS NORTHERN KANSAS ON THURSDAY. TOWARDS THE SURFACE, A COLD
FRONT IS PROGGED TO MOVE SOUTH ACROSS NEBRASKA AND INTO NORTHERN
KANSAS WEDNESDAY AFTERNOON BEFORE BECOMING STATIONARY WEDNESDAY
NIGHT. MEANWHILE, A DRYLINE WILL FORM ACROSS WESTERN KANSAS IN THE
AFTERNOON. A FEW THUNDERSTORMS MAY FORM IN THE LATE AFTERNOON ACROSS
CENTRAL AND SOUTH CENTRAL KANSAS IN THE LATE AFTERNOON INTO THE
EARLY EVENING. A FEW THUNDERSTORMS WILL THEN BE POSSIBLE ACROSS THE
AFOREMENTIONED FRONT ACROSS CENTRAL AND WEST CENTRAL KANSAS IN THE
EVENING. SKIES WILL GENERALLY BE PARTLY CLOUDY DURING THE DAY
BECOMING MOSTLY CLOUDY ACROSS MUCH OF WESTERN KANSAS DURING THE
OVERNIGHT PERIOD. ALTHOUGH, FAR WESTERN KANSAS SHOULD REMAIN MOSTLY
CLEAR THROUGHOUT THE DAY AND NIGHT. WINDS WEDNESDAY WILL GENERALLY
BE FROM A SOUTHERLY DIRECTION DURING THE DAY BECOMING LIGHT AND
VARIABLE OVERNIGHT.
THE FRONTAL BOUNDARY THEN MOVES BACK NORTH AS A WARM FRONT ON
THURSDAY WITH PARTLY CLOUDY SKIES ACROSS WESTERN KANSAS. A DRYLINE
WILL REMAIN PERSISTENT ACROSS WESTERN KANSAS AND MAY ALLOW FOR AN
ISOLATED THUNDERSTORM OR TWO TO FORM EAST OF HIGHWAY 83 THURSDAY
AFTERNOON. THESE STORMS WILL LIKELY PERISH SHORTLY AFTER SUNSET
GIVEN ABSENCE OF LARGE SCALE FORCING FOR ASCENT. ALSO, A FEW MODELS
SUGGEST A CLUSTER OF THUNDERSTORMS OR A MCS TO MOVE ACROSS NEBRASKA
OR NORTHERN KANSAS. THIS WILL NEED TO BE MONITORED IN CASE FUTURE
MODELS PLACE THIS CHANCE FARTHER SOUTH.
UPPER LEVEL RIDGING BUILDS ACROSS THE PLAINS FRIDAY WITH AN UPPER
LEVEL TROUGH DIGGING INTO THE WESTERN UNITED STATES. THERE WILL ONCE
AGAIN BE A VERY SLIGHT CHANCE OF ISOLATED THUNDERSTORMS ACROSS
CENTRAL AND SOUTH CENTRAL KANSAS IN THE AFTERNOON. HOWEVER, AN EML
BECOMES MORE PREVALENT AND MAY CAP ANY CONVECTION FROM OCCURRING.
MOSTLY CLEAR SKIES WILL BE FOUND ACROSS WESTERN KANSAS WITH A FEW
CUMULUS CLOUDS IN THE AFTERNOON.
.THIS WEEKEND INTO EARLY NEXT WEEK...
SATURDAY CONTINUES TO BE THE BEST CHANCE OF PRECIPITATION, BUT ONCE
AGAIN GENERALLY CONFINED TO CENTRAL AND SOUTH CENTRAL KANSAS. THIS
IS DUE TO THE AFOREMENTIONED UPPER LEVEL TROUGH SPINNING INTO THE
ROCKIES AND AN UPPER LEVEL JET NOSING INTO WESTERN KANSAS. TOWARDS
THE SURFACE, AN AREA OF LOW PRESSURE AND DRYLINE WILL INTENSIFY
ACROSS WESTERN KANSAS AS THE DAY PROGRESSES. LOW LEVEL CONVERGENCE
SHOULD BE STRONG ENOUGH GIVEN THE INCREASED LARGER SCALE UPWARD
VERTICAL MOTION TO PROMOTE A FEW SEVERE STORMS. MID RANGE MODELS
CONTINUE TO INDICATE AMPLE LOW LEVEL MOISTURE AHEAD OF THIS LOW WITH
ENOUGH WIND SHEAR TO PROMOTE SUPERCELL DEVELOPMENT. THUNDERSTORMS
CONTINUE ACROSS THIS AREA SATURDAY NIGHT INTO SUNDAY MORNING BUT
SHOULD BECOME LESS INTENSE DUE TO THE LACK OF DAYTIME HEATING. A
COLD FRONT IS FORECAST TO MOVE THROUGH THE AREA SUNDAY SHIFTING
WINDS TO MORE OF A NORTHERLY DIRECTION. DRIER CONDITIONS ARE THEN
SUGGESTED BY THE LONG RANGE MODELS DURING THE FIRST PART OF NEXT
WEEK AS AN UPPER LEVEL RIDGE BUILDS ACROSS THE WESTERN UNITED STATES
AND SURFACE HIGH PRESSURE BUILDS INTO THE AREA.
.TEMPERATURES...
TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGHOUT THE REMAINDER OF
THE WEEK INTO THE WEEKEND. HIGHS WILL GENERALLY BE IN THE 80S WITH
THE EXCEPTION OF FRIDAY AND SATURDAY WHERE 90S WILL BE POSSIBLE.
LOWS WILL GENERALLY BE IN THE LOWER 60S WITH THE EXCEPTION OF FAR
WESTERN KANSAS WHERE UPPER 50S WILL BE POSSIBLE. MODELS SUGGEST A
SLIGHT COOL DOWN BY THE BEGINNING OF NEXT WEEK WITH HIGHS IN THE 70S
AND LOW 80S WITH LOWS IN THE 50S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1200 PM CDT TUE MAY 14 2013
VFR CIGS EXPECTED THROUGH PD. SOUTHWESTERLY WINDS 18-23 KT WILL CONTINUE
THIS AFTERNOON AND EVENTUALLY BACK SOUTHERLY 10-15 KT BY DUSK.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 60 89 60 85 / 0 20 10 20
GCK 58 92 59 86 / 10 10 10 20
EHA 56 91 58 89 / 0 10 10 10
LBL 57 92 60 88 / 0 10 10 10
HYS 59 90 60 84 / 10 20 20 30
P28 63 86 63 83 / 0 20 20 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR KSZ043>045-
062>064-075>078-084>088.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...SUGDEN
LONG TERM...HOVORKA_42
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
446 PM EDT TUE MAY 14 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 422 PM EDT TUE MAY 14 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A ZONAL MID/UPPER LEVEL
PATTERN ACROSS THE NRN CONUS WITH A PROMINENT SHORTWAVE TROUGH NEAR
WINNIPEG. AT THE SFC...A 992 MB LOW WAS ALSO LOCATED OVER SE
MANITOBA WITH A COLD FRONT THROUGH NW MN INTO ERN SD. A WARM FRONT
STRETCHED FROM CNTRL MN INTO SRN WI. RADAR INDICATED WEAK RETURNS
WITH VERY LIGHT SHOWERS(VIRGA OR SPRINKLES) THROUGH CNTRL UPPER MI
AS THE BAND OF 310K (750-600 MB)ISENTROPIC LIFT MOVES THROUGH THE
AREA. SATELLITE SHOWED SKIES CLEARING OVER THE WEST AS DRIER AIR
BEHIND THE PCPN BAND MOVES IN.
TONIGHT...MODELS SUGGEST THAT AS THE MID LEVEL SHRTWV TROUGH AND
ASSOCIATED SFC TROUGH MOVES THROUGH UPPER MI SOME SHOWERS MAY
DEVELOP...MAINLY ACROSS NRN LAKE SUPERIOR AND POSSIBLY INTO THE NRN
PORTIONS OF UPPER MI ON THE SRN TAIL OF THE STRONGER QVECTOR CONV
AND FAVORABLE ISENTROPIC ASCENT JUST AHEAD OF THE SFC TROUGH. MUCAPE
VALUES (LIFTING FROM NEAR 750 MB) OF 500-1000 J/KG STILL SUPPORT A
CONDITIONAL THREAT OF TSRA. ALTHOUGH EFFECTIVE SHEAR VALUES ARE
MARGINAL (20-30 KT) SOME SMALL HAIL MAY BE POSSIBLE WITH ANY TSRA
THAT DEVELOP. CONFIDENCE IN SHRA/TSRA DEVELOPMENT IS LIMITED AS
MODELS HAVE TRENDED TOO HIGH WITH LOW LEVEL MOISTURE AVAILABILITY.
SO...ONLY LOWER END CHANCE POPS WERE INCLUDED.
WED...MODEL SOUNDINGS SHOW STRONG MID-LVL DRYING/SUBSIDENCE IN THE WAKE OF
THE COLD FRONT AS 850 MB TEMPS DROP TO AROUND 5C EARLY WED BUT
REBOUND TO TO AROUND 8C-9C WED AFTERNOON. MIXING HEIGHTS ABOVE 800
MB SHOULD MIX A SIGNIFICANT ENOUGH PORTION OF THE VERY DRY 800-650 MB
LAYER TO DROP DEWPOINTS INLAND TO AROUND 30F. WITH TEMPS INTO THE
LOWER TO MID 70S...RH VALUES WILL DROP TO AROUND 20 PERCENT. NW WIND
SHOULD ALSO INCREASE TO AROUND 15 MPH WITH GUSTS OF 20-25 MPH IN THE
AFTERNOON. SO...A FIRE WEATHER WATCH WAS ISSUED FOR MOST OF INLAND
WEST AND CENTRAL UPPER MICHIGAN.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 444 PM EDT TUE MAY 14 2013
OUR STRONGER WINDS WILL QUICKLY DIMINISH WEDNESDAY NIGHT...EVEN WITH
A REINFORCING SFC TROUGH STRETCHED W-E OVER LAKE SUPERIOR AT 06Z
THURSDAY SINKING SE ACROSS EASTERN UPPER MI BY 12Z THURSDAY. WITH
THAT RH VALUES SHOULD QUICKLY REBOUND TO 35 PERCENT OR BETTER BY 03Z
THURSDAY.
BEHIND THE EXITING TROUGH...HIGH PRESSURE SITUATED OVER S CENTRAL
CANADA WEDNESDAY NIGHT WILL PUSH ACROSS THE CWA AND BE DIRECTLY
OVERHEAD DURING THE DAY THURSDAY...BEFORE SLOWLY EXITING EASTERN
UPPER MI/LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY.
THURSDAY WILL BE DRY ONCE AGAIN FOR SOUTH CENTRAL AREAS...AND IN
PARTICULAR GOGEBIC...ONTONAGON...IRON...AND DICKINSON COUNTIES.
WINDS WILL BE MUCH LIGHTER THAN WEDNESDAY GIVEN THE DIMINISHED
PRESSURE GRADIENT...AVERAGING 5-10KTS. A WILDFIRE POTENTIAL
STATEMENT MAY BE NEEDED...BUT IS REALLY MARGINAL GIVEN THE NEAR
NORMAL TEMPS FOR THIS TIME OF YEAR...AND LIGHTER WINDS. THE WINDS
ARE THE MAIN THREAT THIS TIME OF YEAR...GIVEN THAT THE MAIN CARRIER
OF FIRES IS THE DRY GRASSES.
THE LINGERING HIGH OVER THE EAST WILL KEEP DRIER AIR IN
PLACE...LIMITING THE POTENTIAL FOR ANY SHOWERS TO MOVE MUCH EAST OF
A LINE FROM MQT TO ESC UNTIL SATURDAY MORNING.
EXPECT INCREASED S FLOW STARTING FRIDAY NIGHT...IN ADVANCE OF A
NEARING LOW DEVELOPING ACROSS THE CENTRAL PLAINS STATES. SEVERAL
WARMER NIGHTS ARE FIGURED WITH MID 40S FOR LOWS FRIDAY NIGHT...NEAR
50F SATURDAY NIGHT AND AGAIN SUNDAY NIGHT. THE LATEST TREND IS TO
MINIMIZE THE POTENTIAL FOR THUNDERSTORM ACTIVITY UNTIL THE SFC LOW
AND 500MB TROUGH GET A BIT CLOSER TO THE CWA...AROUND OR AFTER THE
SUNDAY TIME PERIOD. EXPECT THE ELONGATED LOW STRETCHING FROM
NORTHEAST MN TO N TX AT 18Z SUNDAY /ECMWF FARTHEST EAST/ TO
CONSOLIDATE OVER WESTERN UPPER MICHIGAN SUNDAY EVENING. THE 12Z GFS
DOES NOT BRING THE LOW TO WESTERN UPPER MI UNTIL TUESDAY. NEEDLESS
TO SAY THIS WILL BE A SLOW MOVING SYSTEM...WITH SEVERAL ROUNDS OF
PRECIP ROTING INTO THE REGION. WILL GO WITH A MODEL CONSENSUS BEYOND
SUNDAY...GIVEN THE LARGER DISCREPANCIES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 139 PM EDT TUE MAY 14 2013
VFR CONDITIONS SHOULD PREVAIL AT ALL THREE TAF SITES THROUGH THE
FORECAST PERIOD. A PERIOD OF MID CLOUDS IS EXPECTED THROUGH MID
AFTERNOON AS A BAND OF DISSIPATING LIGHT SHOWERS OR SPRINKLES MOVES
THROUGH WRN UPPER MI. ANOTHER ROUND OF ISOLD SHRA/TSRA POSSIBLE THIS
EVENING AS PRIMARY SFC FRONT ARRIVES. PLENTY OF DRY AIR REMAINS OVER
THE AREA WHICH MAY INHIBIT DEVELOPMENT. WENT FOR SHORT PERIOD OF
VCSH AT CMX WHICH IS IN BEST PROXIMITY TO A DISTURANCE TO THE NORTH
AND LIFT AHEAD OF A WARM FRONT...THEN SHARP DRYING/CLEARING
OVERNIGHT TONIGHT. WILL ALSO SEE GUSTY WEST WINDS IN WAKE OF THE
FRONT...STRONGEST AT THE MORE EXPOSED KCMX.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 422 PM EDT TUE MAY 14 2013
SOUTHERLY FLOW WAS INCREASING AHEAD OF A LOW PRESSURE SYSTEM MOVING
EAST THROUGH SOUTHERN CANADA. WINDS INCREASE TO 25 KTS TONIGHT INTO WED
BUT WILL BE LIMITED AS LOW LEVEL WARM AIR ADVECTION RESULTS IN
INCREASING STABILITY. WINDS ARE EXPECTED TO REMAIN BELOW
30KTS LATER THIS WEEK AND INTO THE WEEKEND. AFTER COOL AND WINTRY
WEATHER FOR THE SPRING SO FAR...SUMMERTIME WEATHER IS BECOMING MORE
COMMON. THUNDERSTORMS ARE POSSIBLE TONIGHT AND ENDING BY
EARLY WEDNESDAY. ANOTHER ROUND OF THUNDERSTORMS WILL BE POSSIBLE
WEST ON SATURDAY/SATURDAY NIGHT...AND ACROSS ALL OF LAKE SUPERIOR
SUNDAY THROUGH MONDAY MORNING.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR MIZ002-004>006-009>014-084-085.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
423 PM EDT TUE MAY 14 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 422 PM EDT TUE MAY 14 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A ZONAL MID/UPPER LEVEL
PATTERN ACROSS THE NRN CONUS WITH A PROMINENT SHORTWAVE TROUGH NEAR
WINNIPEG. AT THE SFC...A 992 MB LOW WAS ALSO LOCATED OVER SE
MANITOBA WITH A COLD FRONT THROUGH NW MN INTO ERN SD. A WARM FRONT
STRETCHED FROM CNTRL MN INTO SRN WI. RADAR INDICATED WEAK RETURNS
WITH VERY LIGHT SHOWERS(VIRGA OR SPRINKLES) THROUGH CNTRL UPPER MI
AS THE BAND OF 310K (750-600 MB)ISENTROPIC LIFT MOVES THROUGH THE
AREA. SATELLITE SHOWED SKIES CLEARING OVER THE WEST AS DRIER AIR
BEHIND THE PCPN BAND MOVES IN.
TONIGHT...MODELS SUGGEST THAT AS THE MID LEVEL SHRTWV TROUGH AND
ASSOCIATED SFC TROUGH MOVES THROUGH UPPER MI SOME SHOWERS MAY
DEVELOP...MAINLY ACROSS NRN LAKE SUPERIOR AND POSSIBLY INTO THE NRN
PORTIONS OF UPPER MI ON THE SRN TAIL OF THE STRONGER QVECTOR CONV
AND FAVORABLE ISENTROPIC ASCENT JUST AHEAD OF THE SFC TROUGH. MUCAPE
VALUES (LIFTING FROM NEAR 750 MB) OF 500-1000 J/KG STILL SUPPORT A
CONDITIONAL THREAT OF TSRA. ALTHOUGH EFFECTIVE SHEAR VALUES ARE
MARGINAL (20-30 KT) SOME SMALL HAIL MAY BE POSSIBLE WITH ANY TSRA
THAT DEVELOP. CONFIDENCE IN SHRA/TSRA DEVELOPMENT IS LIMITED AS
MODELS HAVE TRENDED TOO HIGH WITH LOW LEVEL MOISTURE AVAILABILITY.
SO...ONLY LOWER END CHANCE POPS WERE INCLUDED.
WED...MODEL SOUNDINGS SHOW STRONG MID-LVL DRYING/SUBSIDENCE IN THE WAKE OF
THE COLD FRONT AS 850 MB TEMPS DROP TO AROUND 5C EARLY WED BUT
REBOUND TO TO AROUND 8C-9C WED AFTERNOON. MIXING HEIGHTS ABOVE 800
MB SHOULD MIX A SIGNIFICANT ENOUGH PORTION OF THE VERY DRY 800-650 MB
LAYER TO DROP DEWPOINTS INLAND TO AROUND 30F. WITH TEMPS INTO THE
LOWER TO MID 70S...RH VALUES WILL DROP TO AROUND 20 PERCENT. NW WIND
SHOULD ALSO INCREASE TO AROUND 15 MPH WITH GUSTS OF 20-25 MPH IN THE
AFTERNOON. SO...A FIRE WEATHER WATCH WAS ISSUED FOR MOST OF INLAND
WEST AND CENTRAL UPPER MICHIGAN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 625 AM EDT TUE MAY 14 2013
MODEL SNDGS SHOW GOOD MID-LVL DRYING/SUBSIDENCE IN THE WAKE OF THE
COLD FRONT AS 8H TEMPS DROP TO 8-9C. MODELS INDICATE PW VALUES DROP
BLO .5 INCH OR OR 60-70 PERCENT OF NORMAL. GFE MIXED DEWPOINT TOOL
FOR THE NAM AND GFS SHOWS POTENTIAL FOR DEWPOINTS TO DROP INTO THE
LOWER TO MID 20S OVER THE WRN INTERIOR. LOOKING AT HOW DRY MODEL
SNDGS ARE ABV 825 MB THESE DEWPOINTS WOULD NOT BE FAR-FETCHED AT
ALL...ESPECIALLY IF WE MIX NEAR 800 MB. WITH T/TD OF 74/24 MIN RH
VALUES WOULD DROP NEAR 15 PERCENT. NW WIND SHOULD STAY JUST BLO RED
FLAG CRITERIA WITH SUSTAINED WINDS AROUND 15 KT AND GUSTS AROUND 20
KT. HOWEVER IF PCPN IS LIMITED TUE NIGHT...FIRE DANGER WILL
DEFINITELY BE A CONCERN FOR WEDNESDAY. DAY SHIFT MAY NEED TO
COORDINATE WITH FIRE WX USERS TODAY TO SEE IF FIRE WEATHER WATCH MAY
BE NEEDED FOR WED AFTERNOON.
MODELS SHOW A TROUGH MOVING THROUGH THE AREA WED NIGHT BUT NO PCPN
IS EXPECTED FM THIS FEATURE AS THE AIRMASS AND FCST WILL REMAIN DRY
INTO FRI MORNING UNDER CONFLUENT FLOW ALOFT AND BUILDING 5H RDG
HEIGHTS. EXPECT THE SURFACE RIDGE OF HIGH PRESSURE TO BE DIRECTLY
OVERHEAD ON THURSDAY WHICH WILL RESULT IN LIGHT WINDS AND LAKE
BREEZES CIRCULATIONS.
INCREASING WAA/ISENTROPIC LIFT FRI AFTERNOON INTO SAT MORNING
SPREADING FM WEST TO EAST ACROSS THE CWA WILL BRING AN INCREASED CHC
OF SHOWERS FRI NIGHT INTO SATURDAY MORNING FOR MUCH OF THE CWA. FCST
SHOWALTER INDICES AND MUCAPE VALUES INDICATE CHC OF THUNDERSTORMS
DURING THIS TIME WILL BE MAINLY CONFINED TO THE WEST HALF OF THE CWA
LATE FRI NIGHT INTO SAT MORNING. AS 850 MB WARM FRONT LIFTS NORTH OF
THE CWA BY SATURDAY AFTERNOON...MODEL SNDGS SUGGEST ENVIRONMENT WILL
BECOME CAPPED BY WARMER/DRIER AIR AND THUS EXPECT A LULL IN SHOWER
ACTIVITY FOR SAT AFTERNOON INTO AT LEAST SAT EVENING.
BOTH THE 00Z ECMWF AND GFS INDICATE A SHORTWAVE LIFTING OUT FM BASE
OF UPR TROUGH OVER THE SRN PLAINS AND TOWARD THE UPPER MS VALLEY ON
SUNDAY. THIS SHORTWAVE WILL HELP PUSH FRONTAL BOUNDARY CLOSER TO THE
UPPER MS VALLEY AND OUR WRN CWA ESPECIALLY SUN AFTERNOON. 8H THETA-E
MAXIMUM ALONG THE FRONTAL BOUNDARY AND CORRESPONDING INCREASE IN
INSTABILITY (MLCAPES REACH 700-1200 J/KG OVER WEST HALF) WILL
WARRANT AN INCREASED CHC OF SHRA AND TSRA FOR SUNDAY ESPECIALLY OVER
THE WEST HALF. WILL MAINTAIN HIGH CHC POPS FOR SHRA/TSRA SUN NIGHT
INTO MONDAY ACROSS THE CWA AS MAIN SHORTWAVE AND ASSOC COLD FRONT
MOVE ACROSS THE UPPER GREAT LAKES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 139 PM EDT TUE MAY 14 2013
VFR CONDITIONS SHOULD PREVAIL AT ALL THREE TAF SITES THROUGH THE
FORECAST PERIOD. A PERIOD OF MID CLOUDS IS EXPECTED THROUGH MID
AFTERNOON AS A BAND OF DISSIPATING LIGHT SHOWERS OR SPRINKLES MOVES
THROUGH WRN UPPER MI. ANOTHER ROUND OF ISOLD SHRA/TSRA POSSIBLE THIS
EVENING AS PRIMARY SFC FRONT ARRIVES. PLENTY OF DRY AIR REMAINS OVER
THE AREA WHICH MAY INHIBIT DEVELOPMENT. WENT FOR SHORT PERIOD OF
VCSH AT CMX WHICH IS IN BEST PROXIMITY TO A DISTURANCE TO THE NORTH
AND LIFT AHEAD OF A WARM FRONT...THEN SHARP DRYING/CLEARING
OVERNIGHT TONIGHT. WILL ALSO SEE GUSTY WEST WINDS IN WAKE OF THE
FRONT...STRONGEST AT THE MORE EXPOSED KCMX.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 422 PM EDT TUE MAY 14 2013
SOUTHERLY FLOW WAS INCREASING AHEAD OF A LOW PRESSURE SYSTEM MOVING
EAST THROUGH SOUTHERN CANADA. WINDS INCREASE TO 25 KTS TONIGHT INTO WED
BUT WILL BE LIMITED AS LOW LEVEL WARM AIR ADVECTION RESULTS IN
INCREASING STABILITY. WINDS ARE EXPECTED TO REMAIN BELOW
30KTS LATER THIS WEEK AND INTO THE WEEKEND. AFTER COOL AND WINTRY
WEATHER FOR THE SPRING SO FAR...SUMMERTIME WEATHER IS BECOMING MORE
COMMON. THUNDERSTORMS ARE POSSIBLE TONIGHT AND ENDING BY
EARLY WEDNESDAY. ANOTHER ROUND OF THUNDERSTORMS WILL BE POSSIBLE
WEST ON SATURDAY/SATURDAY NIGHT...AND ACROSS ALL OF LAKE SUPERIOR
SUNDAY THROUGH MONDAY MORNING.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR MIZ002-004>006-009>014-084-085.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...VOSS
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
126 PM CDT TUE MAY 14 2013
.UPDATE...
ISSUED AT 1241 PM CDT TUE MAY 14 2013
DECAYING CLOUDS AND SHOWERS NOW OVER WRN WI HAS GENERATED A STRONG
WARM FRONT ACROSS MN FROM ABOUT ABOUT DODGE CENTER...TO LE SEUR
AND UP TO ABOUT MORRIS...WHERE IT MEETS UP WITH A N-S ORIENTED
"COLD" FRONT THAT SITS JUST EAST OF FERGUS FALLS TO MARSHALL AT 1
PM. THIS WARM FRONT IS PROBABLY LEADING TO SOME COLD FEET FOR
FORECASTERS IN THE TWIN CITIES AND CENTRAL MN...WHERE AT 1 PM IT
WAS ONLY 81 AT MSP. HOWEVER...TO THOSE QUESTIONING 90S OCCURRING
IN THE TWIN CITIES...BE PATIENT...TEMPERATURES ON THE OTHER SIDE
OF THE WARM REALLY TAKE OFF. FOR INSTANCE...OLIVIA WENT FROM 81
TO 95 IN 90 MINUTES AND MANKATO WENT FROM 84 AT NOON TO 97 AT 1
PM. SO BE PATIENT...ALL IT WILL TAKE IS AN HOUR OR TWO IN THE WARM
SECTOR TO START PUSHING TEMPERATURES INTO THE MID 90S! STILL
CONFIDENT THAT THE RECORD OF 95 AT MSP IS VERY MUCH IN JEOPARDY
TODAY.
FINALLY...18Z AVIATION DISCUSSION ADDED BELOW.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 440 AM CDT TUE MAY 14 2013
THERE ARE MANY CONCERNS TODAY AS A LOW PRESSURE SYSTEM AND COLD
FRONT MOVE ACROSS THE FA DURING THE AFTERNOON AND EVENING. A SMALL
COMPLEX OF THUNDERSTORMS DID DEVELOP OVER NORTH DAKOTA OVERNIGHT AS
EXPECTED. THIS AREA OF PRECIPITATION WILL ADVANCE ACROSS NORTHERN
MN THIS MORNING. CONSENSUS FROM THE WRF MODELS WAS LITTLE
(SPRINKLES) OR NOTHING REACHING DOWN INTO CENTRAL MN OTHER THAN
SOME CLOUDS. BY LATE MORNING...THE LOW AND COLD FRONT SHOULD BE
INTO FAR WESTERN AREAS OF MN. SOUTH TO SOUTHWEST WINDS WILL INCREASE
AHEAD OF THE FRONT WHILE RATHER STRONG WEST/NORTHWEST WINDS OCCUR
IN THE WAKE OF THE FRONT. A LOW LEVEL THERMAL RIDGE WILL ADVANCE
NORTHEAST FROM THE CENTRAL PLAINS AND REACH INTO THE TWIN CITIES
BY LATE IN THE AFTERNOON. THE SHORT TERM MODELS REMAIN CONSISTENT
ON 23-26 DEG C AIR AT 850MB FROM THE TWIN CITIES ON SOUTHWEST INTO
NORTHERN IA RESPECTIVELY. HIGHS RECENTLY TO OUR WEST AND NORTHWEST
(CANADA) HAVE BEEN RUNNING REAL CLOSE TO 20 DEGREES ABOVE THESE
CONVERTED VALUES. THIS WOULD YIELD HIGHS FROM 93 TO 99 DEGREES.
AS A RESULT... OUR CURRENT FORECAST WAS RAISED A FEW DEGREES...
ESPECIALLY ACROSS SOUTH CENTRAL MN... WHERE THE RAP SOUNDINGS WERE
SHOWING HIGHS OF 100-103. THIS ALSO RESULTED IN A RECORD HIGH BEING
FORECAST FOR THE TWIN CITIES.
THE HEAT TODAY HAS LEAD TO THE ISSUANCE OF A HEAT ADVISORY FROM
THE TWIN CITIES ON SOUTH AND SOUTHWEST TO ALBERT LEA AND REDWOOD
FALLS. THIS IS A DRY HEAT BEING ACCOMPANIED BY 20 TO 25 MPH WINDS
DURING THE AFTERNOON... WHICH MAY LEAD TO DEHYDRATION ISSUES FOR
THOSE WORKING OUTSIDE. ANOTHER IMPORTANT ISSUE IS THAT THE TWIN
CITIES HAS ONLY BEEN IN THE 80S ONCE SO FAR THIS YEAR WITH 81
DEGREES ON APRIL 28TH. THIS BURST OF HEAT MAY LEAD TO HEALTH
ISSUES.
ANOTHER CONCERN TODAY IS THE POTENTIAL FOR WIND ADVISORY CRITERIA
BEING MET IN THE NORTHWEST CWA IN THE MID TO LATE AFTERNOON HOURS.
THE RAP LOW LEVEL WINDS IN THE 200-300 FOOT RANGE ARE FORECAST IN
THE UPPER 20 KNOT RANGE. THIS IS THE HIGHEST OF ALL THE GUIDANCE.
THE NAM WINDS WERE MORE IN THE 23-24 KNOT RANGE WHICH BLENDED WELL
WITH THE LAMP GUIDANCE. CRITERIA FOR A WIND ADVISORY HAS A BETTER
CHANCE OF BEGIN MET OVER NORTH DAKOTA. AT THIS POINT WE HELD OFF
ON ISSUING AN ADVISORY.
FINALLY...ALTHOUGH A STRONG CAP EXISTS IN THE 700-750MB RANGE
TODAY...THERE REMAINS SOME POTENTIAL FOR CONVECTION TO BREACH THE
CAP AND DEVELOP DURING THE LATE AFTERNOON/EVENING ALONG THE
FRONT... MAINLY TO THE EAST AND SOUTH OF THE TWIN CITIES. WE KEPT
THE SMALL CHANCES FOR THUNDERSTORMS AS IS. OUR LOCAL WRF WAS THE
MOST AGGRESSIVE WITH ACTIVITY DEVELOPING FROM JUST SOUTH OF THE
TWIN CITIES TO OMAHA AROUND 21Z...WHILE THE NMM WRF HAS SOME
STORMS JUST EAST OF US. MOST OF THE SOLUTIONS SHOW A HIGHER CHANCE
FOR STORMS OVER IA TONIGHT AS WELL AS IN NORTHEAST WI. GIVEN THE
SHEAR FORECAST...STORMS THAT DO DEVELOP COULD BECOME SEVERE WITH
LARGE HAIL AND DAMAGING WINDS... ESPECIALLY WITH THE INVERTED V
SOUNDING. NAM DOWNDRAFT CAPE VALUES ARE ON THE ORDER OF 1000 J/KG
OVER WEST CENTRAL WI AND SE MN LATE THIS AFTERNOON AND EVENING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 415 AM CDT TUE MAY 14 2013
WEDNESDAY THROUGH MONDAY...QUIET AND SEASONABLE WEATHER WILL GIVE
WAY TO A WETTER PATTERN AT THE END OF THE PERIOD. SEVERE WEATHER IS
ALSO POSSIBLE FOR THE WEEKEND. EARLY MORNING NORTHERN HEMISPHERIC IR
IMAGERY TOGETHER WITH THE ECMWF 250MB HEIGHTS AND WINDS IDENTIFIED
ZONAL FLOW ACROSS THE WESTERN CONUS...WITH A LOW AMPLITUDE PATTERN
ACROSS THE PACIFIC. FOR WEDNESDAY AND THURSDAY THIS ZONAL FLOW WILL
SET UP ACROSS INTERNATIONAL BORDER...WITH NEGATIVE VORTICITY
ADVECTION AND WEAK SUBSIDENCE ACROSS THE UPPER MIDWEST. THIS WILL
RESULT IN TWO DRY DAYS WITH LIGHT WINDS AND TEMPERATURES 5 TO 10
DEGREES ABOVE THE SEASONAL AVERAGE FOR MID MAY.
BY THURSDAY NIGHT THE AFOREMENTIONED LOW AMPLITUDE JET ACROSS THE
PACIFIC WILL BEGIN TO DIG ACROSS THE WESTERN US...WITH A BROAD AREA
OF LEE SIDE TROUGHING ALONG THE EASTERN SPINE OF THE ROCKIES. THIS
WILL INDUCE SOUTHERLY FLOW WITH GULF MOISTURE TRANSPORT ACROSS THE
CENTRAL CONUS...AND GRADUALLY BUILD AN UPPER LEVEL RIDGE THURSDAY
NIGHT INTO FRIDAY. MEANWHILE THE COLD FRONT THAT WILL HAVE PASSED
THROUGH THE AREA ON TUESDAY AND STALL OUT ACROSS SOUTHERN IOWA WILL
LIFT NORTHWARD AS A WARM FRONT. LOW LEVEL THETA_E ADVECTION AS SEEN
IN THE H925-850 LAYER SHOULD PROMOTE THUNDERSTORM DEVELOPMENT ALONG
THE WARM FRONT...WHILE THE UPPER LEVEL ANTICYCLONIC FLOW ALOFT
ALLOWS EVACUATES THE OUTFLOW FROM THESES STORMS AND ALLOWS THEM TO
PERSIST. DIFFICULT TO QUANTIFY THE CONVECTIVE POTENTIAL SINCE THE
LOW LEVEL MOISTURE HAS BEEN UNRELIABLE LATELY. HOWEVER...THE
SYNOPTIC SETUP WITH GULF MOISTURE ADVECTION INCREASES CONFIDENCE
THAT THESE MOISTURE DEPENDENT VARIABLES...A.K.A. CAPE...ARE
REASONABLY REPRESENTED. DEEP LAYER SHEAR PROFILES VARY DEPENDING ON
THE TIMING AND PLACEMENT OF THE WARM FRONT...BUT BOTH THE 14.12 GFS
AND ECMWF ARE IN GOOD AGREEMENT AND LIFT THE FRONT THROUGH THE CWA
ON FRIDAY. MEANWHILE THE UPPER LEVEL JET WILL CONTINUE TO CARVE OUT
A TROUGH OVER THE FOUR CORNERS REGION. THE GFS...GEM...AND ECMWF ALL
DEVELOP A SURFACE LOW AND TRACK IT ACROSS THE UPPER MIDWEST FOR THE
WEEKEND...BRINGING CONTINUED CHANCES FOR PRECIP. THE RUN TOTAL
PRECIP FROM THE GFS AND ECMWF INDICATE THAT OVER 3 INCHES OF RAIN
ARE POSSIBLE. WITH THIS PROLONGED PERIOD OF PRECIP. IN
SUMMATION...EXPECT AN MCS TO DEVELOP THURSDAY NIGHT AND MOVE ACROSS
THE REGION FRIDAY AS THE WARM FRONT LIFTS NORTHWARD. THEN WILL SEE
CONTINUES CHANCES FOR THUNDERSTORMS SATURDAY AND SUNDAY AS THE UPPER
LEVEL DYNAMICS BECOME MORE FAVORABLE FOR ASCENT. SEVERE WEATHER
REMAINS POSSIBLE...BUT CONFIDENCE IN THE EXACT PLACEMENT OF THE
MESOSCALE FEATURES IS LOW AT THIS TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1241 PM CDT TUE MAY 14 2013
WARM FRONT MENTIONED IN UPDATE LEADING TO BIGGEST AVIATION ISSUE
THIS PERIOD...WIND DIRECTIONS. NORTH OF THE WARM FRONT...WINDS
HAVE BACKED CONSIDERABLY MORE THAN EXPECTED...WITH STC/MSP/RNH/EAU
ALL EXPERIENCING ESE WINDS. COLD FRONT IN THE AREA OF AXN RIGHT
NOW AND 12Z TAFS STILL HAD FROPA AND WIND SHIFT TIMED WELL...SO
MADE FEW CHANGES TO THE TIMING OF THE FROPA WITH THESE TAFS. WARM
SECTOR JUST TO HOT/DRY TO THINK THERE IS EVEN A REMOTE CHANCE FOR
A TSRA...SO DID NOT CONTINUE MENTION OF TS AT EAU. REST OF TAF
LOOKS GOOD...WITH WEAKER NW WINDS AND MAINLY CLEAR SKIES EXPECTED
FROM TONIGHT THROUGH WEDNESDAY.
KMSP...OUTSIDE OF TWEAKING WIND DIRECTION TO BE MORE SE AT THE
BEGINNING...FEW CHANGES WERE NEEDED FOR THE TAF. EXPECT A FAIRLY
RAPID VEERING OF WINDS THIS AFTERNOON AS THE COLD FRONT MOVES
THROUGH BETWEEN 21 AND 22Z. DURING THIS HOUR WIND SPEEDS WILL
LIKELY BACK OFF SOME..BUT EXPECT 270-300 WINDS TO QUICKLY PICK UP
IN STRENGTH AND GUSTINESS IN ITS WAKE. LOOKS LIKE THE WIND SHIFT
SHOULD COME IN JUST BEFORE THE EVENING PUSH STARTS...SO SHOULD BE
ABLE TO GET RUNWAYS TURNED AROUND BEFORE PEAK VOLUME HITS.
/OUTLOOK FOR KMSP/
THU...VFR. LGT AND VRBL WINDS.
FRI...VFR WITH MVFR/-TSRA LIKELY. SE WINDS 10 KTS.
SAT...MVFR OR LOWER WITH -TSRA LIKELY. SE WINDS 5-10 KTS.
&&
.FIRE WEATHER...
ISSUED AT 440 AM CDT TUE MAY 14 2013
A RED FLAG WARNING NOW COVERS ALL OF OUR MN COUNTIES FOR THIS
AFTERNOON AND EARLY EVENING. A DRY SURGE OF HEAT WILL OCCUR TODAY
WITH AFTERNOON HUMIDITY VALUES LOWERING TO A FEW PERCENT ABOVE AND
BELOW 20. THE VERY LOW HUMIDITY COUPLED WITH SOUTHWEST TO WEST
WINDS FROM 20 TO 25 MPH ...WITH GUSTS TO 35 MPH... COULD LEAD TO
DANGEROUS WILDFIRE CONDITIONS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR MNZ041>045-
047>070-073>078-082>085-091>093.
HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR MNZ059>063-065>070-
073>077-082>085-091>093.
WI...NONE.
&&
$$
UPDATE...MPG
SHORT TERM...RAH
LONG TERM...JRB
AVIATION...MPG
FIRE WEATHER...RAH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1239 PM CDT TUE MAY 14 2013
.UPDATE...
ISSUED AT 1238 PM CDT TUE MAY 14 2013
LITTLE CHANGE FOR THIS UPDATE. TWEAKED TEMPS AND DEW POINTS TO
MATCH THE CURVE HOWEVER DID NOT ALTER MAX T OR MIN RH. IN THE LAST
HOUR HAVE HAD WINDS STARTING TO PICK UP WITH GUSTS BETWEEN 30 AND
38 KTS. WIND AND RED FLAG HEADLINES IN EFFECT TO 9PM LOOK APROPOS.
UPDATE ISSUED AT 959 AM CDT TUE MAY 14 2013
SHOWERS HAVE EXITED THE AREA AND HAVE REMOVED POPS FOR ALL BUT THE
NORTHERN RRV INTO THE LAKE OF THE WOODS AREA FOR POSSIBLE
REDEVELOPMENT THIS AFTERNOON. AS OF 14Z WEST WIND SHIFT JUST EAST
OF BISMARCK NORTH TO MCCLUSKY NEAR RUGBY TO BOTTINEAU. BEHIND THE
FROPA STILL EXPECTING EFFICIENT MIXING TO 750MB...ALLOWING FOR
RAPID WARM UP. GUSTS BETWEEN 40 AND 50 MPH STILL EXPECTED.
UPDATE ISSUED AT 658 AM CDT TUE MAY 14 2013
SHOWERS AND THUNDERSTORMS HAVE BECOME MORE NUMEROUS ACROSS THE
FORECAST AREA...WITH A STRONG LINE SEGMENT PRODUCING SPORADIC
SEVERE (50+ KTS) DOWNBURST WINDS ACROSS BARNES/CASS COUNTIES.
INCREASED POPS TO 100 PERCENT TO ACCOUNT FOR CURRENT CONVECTIVE
ACTIVITY. ISOLATED STRONG TO SEVERE WINDS ARE POSSIBLE ELSEWHERE
WITH THIS LINE AS ITS FORWARD PROPAGATION IS NEAR 60 MPH. PERSONS
IN THE PATH OF THIS STORM SHOULD PAY CLOSE ATTENTION TO THE LATEST
STATEMENTS AND/OR WARNINGS. REST OF THE FORECAST OK FOR NOW WITH
NO OTHER MAJOR CHANGES.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 355 AM CDT TUE MAY 14 2013
FORECAST CHALLENGES INCLUDE SHOWERS AND THUNDERSTORMS THIS
MORNING...FOLLOWED BY STRONG WINDS AND CRITICAL FIRE WEATHER
CONDITIONS THIS AFTERNOON. GFS/NAM/ECMWF/GEM ARE IN GOOD
AGREEMENT...BUT WILL USE LATEST HRRR FOR PRECIPITATION TRENDS
THROUGH 18 UTC. THEREAFTER...A BLENDED SOLUTION SHOULD SUFFICE.
08 UTC WATER VAPOR LOOP SHOWS A STRONG...YET PROGRESSIVE SHORT
WAVE MOVING ALONG THE CANADIAN BORDER AND INTO NORTHEAST MT. A
CLUSTER OF SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ACROSS CENTRAL
ND IN AN AREA OF WEAK ELEVATED INSTABILITY AND INCREASED
DIVERGENCE ALOFT AHEAD OF A SURFACE COLD FRONT WHICH STRETCHES
FROM NEAR WILLISTON TO MILES CITY MT. LATEST HRRR SHOWS THIS
CONVECTIVE ACTIVITY MOVING EASTWARD THROUGH THE EARLY MORNING AND
INTO THE MN ARROWHEAD AFTER 15 UTC. INCREASED POPS FROM 60 TO 80
PERCENT ACROSS THE NORTHERN HALF OF THE FORECAST AREA THIS MORNING
WHERE A QUICK QUARTER INCH OF RAIN IS POSSIBLE... ESPECIALLY FOR
THOSE AREAS THAT SEE THUNDERSTORMS.
THE COLD FRONT IS FORECAST TO REACH THE VALLEY FLOOR BY 18 UTC.
WITH STRONG LOW-MID LEVEL COLD AIR ADVECTION IN ITS WAKE...AN
ADIABATIC BOUNDARY LAYER TO 750 HPA AND 30 TO 40 KTS TO MIX
DOWN...EXPECT WINDY CONDITIONS TO DEVELOP FROM WEST TO EAST
THROUGH THE AFTERNOON. WEST WINDS FROM 30 TO 40 MPH WITH GUSTS UP
TO 50 MPH ACROSS THE HIGHER TERRAIN OF EASTERN ND NECESSITATES A
WIND ADVISORY FROM 17 TO 02 UTC FOR ALL AREAS EXPECT THE FAR
EASTERN COUNTIES. WILL CANCEL THE HIGH WIND WATCH AS WINDS ARE NOT
EXPECTED TO REACH CRITERIA. HIGH TEMPERATURES TODAY STILL
EXPECTED TO CLIMB INTO THE MID 70S TO MID 80S BEFORE FRONTAL
PASSAGE AND WHEN COMBINED WITH STRONG WINDS AND LOW RH WILL CREATE
DANGEROUS FIRE WEATHER CONDITIONS. SEE DISCUSSION BELOW FOR MORE
DETAIL.
THIS AFTERNOON THROUGH WEDNESDAY WILL BE DRY AS SURFACE HIGH
PRESSURE BUILDS ACROSS THE REGION. WINDS WILL DIMINISH SOMEWHAT
AFTER SUNSET...BUT REMAIN ELEVATED FROM THE WEST-NORTHWEST TONIGHT
THROUGH WEDNESDAY. TOMORROW WILL BE A BIT COOLER WITH AFTERNOON
HIGHS IN THE 70S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 355 AM CDT TUE MAY 14 2013
WEDNESDAY NIGHT THROUGH MOST OF THURSDAY WILL BE DRY...BUT EXPECT
PRECIPITATION CHANCES TO INCREASE THURSDAY NIGHT AHEAD OF THE NEXT
PACIFIC TROUGH. GFS/ECMWF BOTH SHOW A WIDE SWATH OF SHOWERS AND
STORMS MOVING INTO EASTERN ND BY 12 UTC FRIDAY. INCREASED POPS
INTO THE HIGH CHANCE CATEGORY...BUT IF MODEL TRENDS CONTINUE...
WILL NEED TO INCREASE FURTHER. DON/T EXPECT MUCH TEMPERATURE
CHANGE FROM WEDNESDAY WITH THURSDAY/S HIGHS IN THE 70S.
00Z ECMWF/GFS WERE IN GOOD AGREEMENT WITH OVERALL PATTERN FRI-MON
IN SHOWING A LARGE 500 MB TROUGH OVER THE ROCKIES LIFTING
NORTHEAST INTO THE NRN PLAINS AND EVENTUAL 500 MB LOW FORMATION IN
MINNESOTA. THIS LEADS TO AN EXTENDED PERIOD OF PRECIPITATION
CHANCES THRU THE PD. SHOWWALTERS FROM THE MODELS PROG INDICATE
SOME THUNDERSTORM POTENTIAL FRI-SUN THEN MOSTLY SHOWERS ON MONDAY.
OVER THE 4 DAY PERIOD...SOME HEAVY RAINFALL TOTALS ARE POSSIBLE
SOMEWHERE IN OUR REGION AS PWATS INCREASE TO 1.50 INCHES OVER SE
ND INTO NRN MN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1238 PM CDT TUE MAY 14 2013
IT WILL BE VERY WINDY THROUGH THIS EVENING...WITH WEST TO NORTHWEST
WINDS GUSTING TO AROUND 35KT AT TIMES. CIGS WILL REMAIN IN THE VFR
CATEGORY WITH MAINLY HIGH CLOUDS AND SOME SHALLOW CUMULUS THIS
AFTERNOON MAINLY IN THE NORTH. WINDS WILL TURN MORE NORTHERLY AFTER
SUNSET AND DECREASE OVERNIGHT.
&&
.FIRE WEATHER...
ISSUED AT 959 AM CDT TUE MAY 14 2013
RED FLAG WARNING CONTINUES FOR ALL OF ERN ND INTO MUCH OF NW/WCNTRL
MN (EXCEPT LAKE OF THE WOODS AND NORTH BELTRAMI REGIONS) FOR 17Z TUE
TO 02Z WED. FUELS REMAIN DRY AND PRIME. WILDFIRE ONGOING NEAR GRYGLA
IN SOUTHEASTERN MARSHALL COUNTY. FUELS REMAIN DRY IN ERN ND AS
WELL...THOUGH PARTS OF NE ND AND FAR NW MN WILL SEE SOME RAINFALL
THIS MORNING. BELIEVE THAT EARLY MORNING LOW PCPN AMTS WILL NOT HAVE
GREAT IMPACT ON DECREASING HUMIDITIES THIS AFTERNOON AS DEEP MIXING
LAYER COMBINES WITH STRONG WEST NORTHWEST WINDS TO YIELD VALUES
BELOW 25 PERCENT EVEN IN WEST CENTRAL MN. WILL MONITOR HUMIDITY
LEVELS THROUGHOUT THE DAY AND ADJUST ACCORDINGLY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...RED FLAG WARNING UNTIL 9 PM CDT THIS EVENING FOR NDZ006>008-
014>016-024-026>030-038-039-049-052>054.
WIND ADVISORY UNTIL 9 PM CDT THIS EVENING FOR NDZ006>008-014>016-
024-026>030-038-039-049-052>054.
MN...RED FLAG WARNING UNTIL 9 PM CDT THIS EVENING FOR MNZ001>005-007-
008-013>017-022>024-027>032-040.
WIND ADVISORY UNTIL 9 PM CDT THIS EVENING FOR MNZ001>005-007-008-
013>016-022-023-027>031-040.
&&
$$
UPDATE...JK
SHORT TERM...ROGERS
LONG TERM...ROGERS/RIDDLE
AVIATION...DK
FIRE WEATHER...WJB
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
325 PM CDT TUE MAY 14 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 211 PM CDT TUE MAY 14 2013
FRONT CONTINUES TO MOVE ACROSS THE CWA THIS AFTERNOON. RECORD HEAT
OUT AHEAD OF THE FRONT WITH LOW TO EVEN MID 100S ACROSS NORTHWEST
IOWA AND PORTIONS OF SOUTHWEST MINNESOTA...AND STILL LOW TO MID 90S
BEHIND THE FRONT ACROSS SOUTHEAST SOUTH DAKOTA. WITH DEWPOINTS
MIXING OUT...NOT MUCH IN THE WAY OF INSTABILITY AHEAD OF THE FRONT.
ALTHOUGH THE HRRR AND RUC HAVE CONTINUED TO SHOW SOME ISOLATED
DEVELOPMENT ALONG THE FRONT BY 22Z. GIVEN THAT BOTH OF THESE SHORT
RANGE MODELS ARE DOING A PRETTY GOOD JOB WITH SURFACE TEMPS AND
DEWPOINTS..THINK SOME ISOLATED CONVECTION MAY FIRE AS WE MIX THROUGH
WHATEVER CAP THERE IS. HOWEVER LOOKS LIKE THIS THREAT IS MAINLY
SOUTH AND SOUTHEAST OF OUR CWA...THUS WILL KEEP THE FORECAST DRY
THROUGH THE EVENING. WEAK COLD AIR ADVECTION CONTINUES THROUGH THE
NIGHT...WITH WINDS WEAKENING. THUS WHILE LOWS WILL BE ABOVE
NORMAL...MAY STILL SEE THEM GET DOWN INTO THE LOW TO MID 50S BY
MORNING IN MOST LOCATIONS.
MID LEVEL FRONTAL BOUNDARY LINGERS OVERHEAD TONIGHT INTO
TOMORROW...WITH A WEAK WAVE RIDING OVER THE RIDGE. SO WILL SEE A
REGION OF WEAK LIFT AND DECENT MID LEVEL LAPSE RATES. HOWEVER THETAE
ADVECTION IS PRETTY WEEK...AND LOW LEVELS WILL REMAIN VERY DRY. WILL
PROBABLY SEE SOME ELEVATED CONVECTION FORM ACROSS WESTERN NEBRASKA
AND SOUTH DAKOTA TONIGHT...WHICH WILL TRY TO MOVE EAST TOWARDS OUR
AREA. HOWEVER GIVEN THE ABOVE LIMITATIONS...THINK THE CHANCE OF
MEASURABLE PRECIP IN OUR CWA IS TOO LOW TO MENTION AT THIS TIME.
HOWEVER CAN NOT RULE OUT AN ISOLATED SHOWER OR SOME SPRINKLES
REACHING THE GROUND ANYTIME FROM LATE TONIGHT THROUGH THE DAY
TOMORROW. HIGH TEMPERATURES A BIT TRICKY GIVEN CLOUD COVER
POTENTIAL. BUT FEEL WE WILL SEE PERIODS OF SUN AS WELL...WITH
GENERALLY PARTLY TO AT TIMES MOSTLY SUNNY SKIES. AND RECENTLY WE
HAVE BEEN GETTING WARMER THAN JUST ABOUT EVERY GUIDANCE...SO DESPITE
CLOUD COVER CONCERNS WENT AHEAD AND RAISED HIGHS A COUPLE
DEGREES...GENERALLY IN THE UPPER 70S TO AROUND 80.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 325 PM CDT TUE MAY 14 2013
THE FRONT SOUTH OF THE AREA WILL BEGIN TO MOVE NORTH AS A WARM
FRONT WEDNESDAY NIGHT AND SHOULD BEGIN TO BRING SOME MORE MOIST
AND UNSTABLE AIR INTO THE AREA BY THE END OF THE NIGHT. LOW
TEMEPRATURES SHOULD BE NEAR SEASONAL VALUES BEFORE MOST OF THE
HUMID AIR GETS HERE ON THURSDAY. THE THREAT OF THUNDERSTORMS IN
WARM ADVECTION PATTERN NORTH OF THE FRONT MAY BEGIN IN THE SOUTH
LATE WEDNESDAY NIGHT. THIS THREAT SHOULD GENERALLY BE AROUND FOR
THE REST OF THE FORECAST...ALTHOUGH WILL KEEP POPS MINIMAL ON
FRIDAY AS IT LOOKS LIKE THERE MAY BE A BREAK ON THAT DAY. THEN THE
THREAT WILL INCREASE AGAIN FOR THE WEEKEND AS MAIN UPPER TROUGH
APPROACHES...WITH THE PEAK THREAT SATURDAY NIGHT. A SEVERE THREAT
OR MODESTLY HEAVY RAIN SEEMS POSSIBLE OVER THE WEEKEND.
INSTABILITY AND MOISTURE UNCERTAIN WITH IT BEING WELL DISCUSSED
ABOUT THE TOO HIGH GFS DEW POINTS. IN ANY EVENT TEMPERATURES WILL
BE WARM DURING THE DAY BUT EVEN WARMER RELATIVE TO NORMAL AT
NIGHT...OR NO REAL HOT SPELL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1227 PM CDT TUE MAY 14 2013
VFR CONDITIONS EXPECTED THROUGH THE PERIOD. WINDS GUSTING TO AROUND
30 KTS WILL CONTINUE THROUGH THE DAY...FROM THE SOUTHWEST AHEAD OF AN
APPROACHING COLD FRONT AND THE NORTHWEST BEHIND IT. WINDS WILL
DIMINISH TONIGHT. WILL LIKELY SEE SOME INCREASING MID CLOUDS LATER
TONIGHT INTO TOMORROW. CHANCE OF A FEW SHOWERS OUT OF THESE
CLOUDS...BUT WITH DRY LOW LEVELS DO NOT THINK MUCH OF ANYTHING WILL
REACH THE SURFACE.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR SDZ255>258.
MN...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR MNZ900.
IA...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR IAZ300-301.
NE...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR NEZ249.
&&
$$
SHORT TERM...CHENARD
LONG TERM...
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
212 PM CDT TUE MAY 14 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 211 PM CDT TUE MAY 14 2013
FRONT CONTINUES TO MOVE ACROSS THE CWA THIS AFTERNOON. RECORD HEAT
OUT AHEAD OF THE FRONT WITH LOW TO EVEN MID 100S ACROSS NORTHWEST
IOWA AND PORTIONS OF SOUTHWEST MINNESOTA...AND STILL LOW TO MID 90S
BEHIND THE FRONT ACROSS SOUTHEAST SOUTH DAKOTA. WITH DEWPOINTS
MIXING OUT...NOT MUCH IN THE WAY OF INSTABILITY AHEAD OF THE FRONT.
ALTHOUGH THE HRRR AND RUC HAVE CONTINUED TO SHOW SOME ISOLATED
DEVELOPMENT ALONG THE FRONT BY 22Z. GIVEN THAT BOTH OF THESE SHORT
RANGE MODELS ARE DOING A PRETTY GOOD JOB WITH SURFACE TEMPS AND
DEWPOINTS..THINK SOME ISOLATED CONVECTION MAY FIRE AS WE MIX THROUGH
WHATEVER CAP THERE IS. HOWEVER LOOKS LIKE THIS THREAT IS MAINLY
SOUTH AND SOUTHEAST OF OUR CWA...THUS WILL KEEP THE FORECAST DRY
THROUGH THE EVENING. WEAK COLD AIR ADVECTION CONTINUES THROUGH THE
NIGHT...WITH WINDS WEAKENING. THUS WHILE LOWS WILL BE ABOVE
NORMAL...MAY STILL SEE THEM GET DOWN INTO THE LOW TO MID 50S BY
MORNING IN MOST LOCATIONS.
MID LEVEL FRONTAL BOUNDARY LINGERS OVERHEAD TONIGHT INTO
TOMORROW...WITH A WEAK WAVE RIDING OVER THE RIDGE. SO WILL SEE A
REGION OF WEAK LIFT AND DECENT MID LEVEL LAPSE RATES. HOWEVER THETAE
ADVECTION IS PRETTY WEEK...AND LOW LEVELS WILL REMAIN VERY DRY. WILL
PROBABLY SEE SOME ELEVATED CONVECTION FORM ACROSS WESTERN NEBRASKA
AND SOUTH DAKOTA TONIGHT...WHICH WILL TRY TO MOVE EAST TOWARDS OUR
AREA. HOWEVER GIVEN THE ABOVE LIMITATIONS...THINK THE CHANCE OF
MEASURABLE PRECIP IN OUR CWA IS TOO LOW TO MENTION AT THIS TIME.
HOWEVER CAN NOT RULE OUT AN ISOLATED SHOWER OR SOME SPRINKLES
REACHING THE GROUND ANYTIME FROM LATE TONIGHT THROUGH THE DAY
TOMORROW. HIGH TEMPERATURES A BIT TRICKY GIVEN CLOUD COVER
POTENTIAL. BUT FEEL WE WILL SEE PERIODS OF SUN AS WELL...WITH
GENERALLY PARTLY TO AT TIMES MOSTLY SUNNY SKIES. AND RECENTLY WE
HAVE BEEN GETTING WARMER THAN JUST ABOUT EVERY GUIDANCE...SO DESPITE
CLOUD COVER CONCERNS WENT AHEAD AND RAISED HIGHS A COUPLE
DEGREES...GENERALLY IN THE UPPER 70S TO AROUND 80.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 343 AM CDT TUE MAY 14 2013
SURFACE HIGH PRESSURE BUILDS SOUTHWARD INTO THE REGION ON WEDNESDAY
AND WEDNESDAY NIGHT...PROVIDING FOR PLEASANT CONDITIONS WITH
TEMPERATURES CLOSE TO NORMAL FOR THIS TIME OF YEAR. THIS WILL PLAY
OUT TO HIGHS IN THE MID AND UPPER 70S...WITH LOWS EARLY ON THURSDAY
IN THE UPPER 40S TO LOWER 50S.
THE HIGH MOVES EASTWARD ON THURSDAY WITH A SOUTHERLY FLOW RETURNING
TO OUR AREA ON THE BACKSIDE OF THE HIGH. THINK MOST OF THE DAY WILL
REMAIN DRY WITH WARMING TEMPERATURES...INTO THE UPPER 70S TO AROUND
80 FOR AFTERNOON HIGHS. CANNOT RULE OUT SOME THUNDERSTORM
DEVELOPMENT IN OUR SOUTHWEST LATER IN THE AFTERNOON...WITH A BETTER
CHANCE ON THURSDAY NIGHT AS A WARM FRONT BEGINS TO LIFT THROUGH
NEBRASKA AND 850 MB CONVERGENCE IS ENHANCED AS A LOW LEVEL JET
DEVELOPS THROUGH THE REGION. DOES APPEAR TO BE ENOUGH ELEVATED
CAPE...500 TO 1000 J/KG...AND EFFECTIVE SHEAR OF AROUND 30 KTS IN
THE EVENING THAT CANNOT RULE OUT A COUPLE OF SEVERE STORMS WITH
LARGE HAIL.
A MESSY PATTERN CONTINUES THROUGH THE EXTENDED...FRIDAY INTO MONDAY
OF NEXT WEEK...WITH PERIODIC CHANCES OF CONVECTION THROUGH THE
PERIOD WITH A BOUNDARY MEANDERING AROUND THE AREA AND A SERIES OF
SUBTLE WAVES TRACKING ACROSS THE REGION. HARD TO TIME THIS
CONVECTION DEPENDENT ON WHERE SYNOPTIC/MESOSCALE FEATURES SET
UP...BUT WITH INCREASING LOW LEVEL MOISTURE AND INSTABILITY ACROSS
THE REGION THROUGH THE WEEKEND THERE IS FAIRLY HIGH CONFIDENCE THAT
CONVECTION WILL OCCUR. CONVECTIVE PARAMETERS WOULD ALSO SUGGEST THAT
SEVERE STORMS WILL BE POSSIBLE FOR THOSE DAYS. AN UPPER LEVEL TROUGH
FINALLY SWINGS OUT OF THE WESTERN U.S. ON SUNDAY AND
MONDAY...KEEPING A CHANCE OF CONVECTION ACROSS THE REGION...AS WELL
AS BRINGING A COOLING TREND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1227 PM CDT TUE MAY 14 2013
VFR CONDITIONS EXPECTED THROUGH THE PERIOD. WINDS GUSTING TO AROUND
30 KTS WILL CONTINUE THROUGH THE DAY...FROM THE SOUTHWEST AHEAD OF AN
APPROACHING COLD FRONT AND THE NORTHWEST BEHIND IT. WINDS WILL
DIMINISH TONIGHT. WILL LIKELY SEE SOME INCREASING MID CLOUDS LATER
TONIGHT INTO TOMORROW. CHANCE OF A FEW SHOWERS OUT OF THESE
CLOUDS...BUT WITH DRY LOW LEVELS DO NOT THINK MUCH OF ANYTHING WILL
REACH THE SURFACE.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR SDZ255>258.
MN...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR MNZ900.
IA...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR IAZ300-301.
NE...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR NEZ249.
&&
$$
SHORT TERM...CHENARD
LONG TERM...JM
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1229 PM CDT TUE MAY 14 2013
.UPDATE...
ISSUED AT 1029 AM CDT TUE MAY 14 2013
FORECAST LOOKS IN PRETTY GOOD SHAPE. RED FLAG WARNING LOOKS
GOOD...WITH BLUSTERY SOUTHWEST WINDS AHEAD OF THE COLD
FRONT...TRANSITIONING TO NORTHWEST BEHIND IT. EXPECT FREQUENT GUSTS
INTO THE 25 TO 35 MPH RANGE WITH RELATIVE HUMIDITY DROPPING TO AROUND
20 PERCENT...OR EVEN A LITTLE LOWER AHEAD OF THE FRONT THIS
AFTERNOON. LEADING EDGE OF THE ACCAS IS A SOME SORT OF BOUNDARY WITH
WINDS TURNING MORE WEST SOUTHWESTERLY BEHIND IT. HOWEVER THE TRUE
COLD FRONT IS BEHIND THIS...HAVING JUST GONE THROUGH CHAMBERLAIN AND
HURON WITH THEIR WINDS TURNING NORTHWEST. WENT AHEAD AND RAISED
HIGHS A FEW DEGREES FOR TODAY...WITH READINGS AROUND 100 LOOKING
LIKELY ACROSS NORTHEAST NEBRASKA AND NORTHWEST IOWA...LOCATIONS THAT
WILL STAY JUST AHEAD OF THE COLD FRONT THROUGH THE PEAK OF DAYTIME
HEATING. CONVECTION CHANCES WITH THE FRONT STILL LOOK LOW WITH
DEWPOINTS MIXING OUT. HOWEVER HRRR IS SHOWING SOME ACTIVITY AFTER
21Z. AND GIVEN THAT ITS BOUNDARY LAYER DEPICTION SEEMS DECENT...CAN
NOT COMPLETELY IGNORE THE CHANCE. HOWEVER IT DOES APPEAR THAT THE
BEST CHANCE WILL STAY SOUTH OF OUR CWA ACROSS NEBRASKA...THUS WILL
KEEP THE FORECAST DRY FOR NOW. ALTHOUGH ANY STORM THAT IS ABLE TO
FORM WOULD BE CAPABLE OF POTENTIALLY SEVERE WIND GUSTS GIVEN THE DRY
PROFILES.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CDT TUE MAY 14 2013
MAIN CHALLENGE FOR TODAY WILL BE WINDS/HUMIDITY LEVELS/ASSOCIATED
FIRE WEATHER CONCERNS IN MIXY ENVIRONMENT AHEAD OF AND BEHIND COOL
FRONT WHICH WILL PUSH SOUTHEAST ACROSS THE REGION THROUGH THE DAY.
LOW LEVEL TEMPERATURES AHEAD OF THE FRONT EASILY SUPPORTIVE OF MID
90S ACROSS MUCH OF NORTHWEST IOWA THIS AFTERNOON...WITH SOME MODELS
SHOWING POTENTIAL FOR HIGHS CLOSER TO OR JUST ABOVE THE CENTURY MARK.
WITH THE STRONG MIXING COMES LIKELIHOOD OF MIXING DRIER AIR ALOFT TO
THE SURFACE. MODELS HAVE BEEN HAVING DIFFICULTY CAPTURING THE DIURNAL
DRYING TREND WITH AFTERNOON MIXING...HANGING ONTO SHALLOW MOISTURE OR
MIXING BOUNDARY LAYER MOISTURE UPWARD RATHER THAN BRINGING DRIER AIR
TO SURFACE AS DEEPER MIXING COMMENCES. RUC SEEMS TO HANDLE IT BETTER
THAN NAM/GFS...AND MORE CLOSELY FOLLOWED THAT IDEA THROUGH THE LATE
MORNING/AFTERNOON...THOUGH NOT QUITE AS DRY AS RUC INDICATES AT THIS
POINT GIVEN EXTREME DISPARITY FROM OTHER MODELS /AS MUCH AS 10-15F
DRIER THAN MOST OTHER GUIDANCE FOR 21Z/. DRIEST AIR SHOULD BE OVER
FAR SOUTHEAST AND WESTERN PARTS OF THE FORECAST AREA DURING PEAK
HEATING...WITH SLIGHT MOISTURE POOLING IN SOMEWHAT LESS MIXY AREA
RIGHT ALONG THE FRONT...FORECAST TO BE JUST EAST OF KYKN-KFSD-KMML
LINE AT 21Z. ALL THIS LEADS TO MINIMUM HUMIDITY LEVELS OF 15-25
PERCENT THIS AFTERNOON... AND THIS ALONG WITH WINDS GUSTING IN THE
25-30KT RANGE STILL SUPPORTIVE OF RED FLAG WARNING WHICH WAS ISSUED
ON THE DAY SHIFT YESTERDAY.
COLD FRONT SETTLES SOUTH OF THE AREA TONIGHT...WITH COOLING
TEMPERATURES AND DYING WINDS OVERNIGHT. LOWS LOOK TO DROP INTO THE
UPPER 40S NORTHWEST...TO MID 50S THROUGH THE LOWER MISSOURI RIVER
VALLEY INTO NORTHWESTERN IOWA.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 343 AM CDT TUE MAY 14 2013
SURFACE HIGH PRESSURE BUILDS SOUTHWARD INTO THE REGION ON WEDNESDAY
AND WEDNESDAY NIGHT...PROVIDING FOR PLEASANT CONDITIONS WITH
TEMPERATURES CLOSE TO NORMAL FOR THIS TIME OF YEAR. THIS WILL PLAY
OUT TO HIGHS IN THE MID AND UPPER 70S...WITH LOWS EARLY ON THURSDAY
IN THE UPPER 40S TO LOWER 50S.
THE HIGH MOVES EASTWARD ON THURSDAY WITH A SOUTHERLY FLOW RETURNING
TO OUR AREA ON THE BACKSIDE OF THE HIGH. THINK MOST OF THE DAY WILL
REMAIN DRY WITH WARMING TEMPERATURES...INTO THE UPPER 70S TO AROUND
80 FOR AFTERNOON HIGHS. CANNOT RULE OUT SOME THUNDERSTORM
DEVELOPMENT IN OUR SOUTHWEST LATER IN THE AFTERNOON...WITH A BETTER
CHANCE ON THURSDAY NIGHT AS A WARM FRONT BEGINS TO LIFT THROUGH
NEBRASKA AND 850 MB CONVERGENCE IS ENHANCED AS A LOW LEVEL JET
DEVELOPS THROUGH THE REGION. DOES APPEAR TO BE ENOUGH ELEVATED
CAPE...500 TO 1000 J/KG...AND EFFECTIVE SHEAR OF AROUND 30 KTS IN
THE EVENING THAT CANNOT RULE OUT A COUPLE OF SEVERE STORMS WITH
LARGE HAIL.
A MESSY PATTERN CONTINUES THROUGH THE EXTENDED...FRIDAY INTO MONDAY
OF NEXT WEEK...WITH PERIODIC CHANCES OF CONVECTION THROUGH THE
PERIOD WITH A BOUNDARY MEANDERING AROUND THE AREA AND A SERIES OF
SUBTLE WAVES TRACKING ACROSS THE REGION. HARD TO TIME THIS
CONVECTION DEPENDENT ON WHERE SYNOPTIC/MESOSCALE FEATURES SET
UP...BUT WITH INCREASING LOW LEVEL MOISTURE AND INSTABILITY ACROSS
THE REGION THROUGH THE WEEKEND THERE IS FAIRLY HIGH CONFIDENCE THAT
CONVECTION WILL OCCUR. CONVECTIVE PARAMETERS WOULD ALSO SUGGEST THAT
SEVERE STORMS WILL BE POSSIBLE FOR THOSE DAYS. AN UPPER LEVEL TROUGH
FINALLY SWINGS OUT OF THE WESTERN U.S. ON SUNDAY AND
MONDAY...KEEPING A CHANCE OF CONVECTION ACROSS THE REGION...AS WELL
AS BRINGING A COOLING TREND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1227 PM CDT TUE MAY 14 2013
VFR CONDITIONS EXPECTED THROUGH THE PERIOD. WINDS GUSTING TO AROUND
30 KTS WILL CONTINUE THROUGH THE DAY...FROM THE SOUTHWEST AHEAD OF AN
APPROACHING COLD FRONT AND THE NORTHWEST BEHIND IT. WINDS WILL
DIMINISH TONIGHT. WILL LIKELY SEE SOME INCREASING MID CLOUDS LATER
TONIGHT INTO TOMORROW. CHANCE OF A FEW SHOWERS OUT OF THESE
CLOUDS...BUT WITH DRY LOW LEVELS DO NOT THINK MUCH OF ANYTHING WILL
REACH THE SURFACE.
&&
.FIRE WEATHER...
ISSUED AT 343 AM CDT TUE MAY 14 2013
RED FLAG WARNING STILL LOOKS WARRANTED FOR THE AFTERNOON AND EARLY
EVENING. GUSTY SOUTHWEST WINDS OF 25 TO 35 MPH AHEAD OF COOL FRONT
WILL SWITCH TO NORTHWEST BEHIND THE FRONT AND REMAIN AS STRONG. ALONG
WITH THE GUSTY WINDS WILL BE DRY RELATIVE HUMIDITY LEVELS IN THE 15
TO 25 PERCENT RANGE...AS DRY AND UNSEASONABLY WARM AIR ALOFT MIXES TO
THE SURFACE. AREAS RIGHT ALONG THE FRONT MAY NOT SEE AS SUSTAINED A
PERIOD OF RED FLAG CRITERIA DUE TO MOISTURE POOLING AND LIGHTER/LESS
GUSTY WINDS WITHIN THE FRONTAL ZONE...BUT SHOULD STILL REACH CRITERIA
AT TIMES. RECENT GREENING OF COOL SEASON GRASSES MAY SLOW FIRE STARTS
ACROSS THE AREA...BUT ANY FIRES THAT DO IGNITE WILL SPREAD VERY
QUICKLY IN THE LINGERING DORMANT TALL GRASSES.
SOME MODELS ALSO INDICATE POTENTIAL FOR EVEN WARMER/DRIER AIR MIXING
TO THE SURFACE AHEAD OF THE FRONT...MAINLY IN NORTHWEST IOWA THIS
AFTERNOON...SO THIS WILL BE WATCHED CLOSELY THROUGHOUT THE DAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR SDZ255>258.
MN...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR MNZ900.
IA...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR IAZ300-301.
NE...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR NEZ249.
&&
$$
UPDATE...CHENARD
SHORT TERM...JH/JM
LONG TERM...JM
AVIATION...CHENARD
FIRE WEATHER...JH
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
155 PM CDT TUE MAY 14 2013
.SHORT TERM.../TONIGHT THROUGH WEDNESDAY NIGHT/...EVEN THOUGH THE
LATEST RUC13 MODEL RUNS CONTINUE TO SHOW SHOWERS DEVELOPING
ACROSS THE CWA THIS AFTERNOON...RADAR AND SATELLITE IMAGES INDICATE
NOT MUCH IN THE WAY OF RAIN DEVELOPING AS OF YET. SURFACE
INSTABILITY IS MARGINAL ACROSS THE RIO GRANDE VALLEY AND THE CLOUD
COVER MAY BE INHIBITING THE INSTABILITY. IN ADDITION...WATER VAPOR
SAT IMAGES AND NAM80 500MB VORTICITY ANALYSIS INDICATE NEGATIVE VORT
CENTER JUST TO THE WEST OF THE AREA. CURRENT FORECAST THINKING IS
THAT AS THE 500MB LOW ACROSS NORTHWEST MEXICO IS KICKED EASTWARD
WITH THE SHORTWAVE TROUGH MOVING INTO SOUTHERN CALIFORNIA...SHOWERS
AND THUNDERSTORMS WILL DEVELOP LATER THIS AFTERNOON INTO THIS
EVENING ACROSS THE MEXICAN PLATEAU AND MOVE EASTWARD INTO THE
WESTERN PORTIONS OF THE CWA TONIGHT INTO EARLY WEDNESDAY. WITH THAT
SAID...WILL ADJUST TIMING OF POPS TONIGHT INTO WED NIGHT AND KEEP AT
LEAST A CHANCE OF RAIN ACROSS MOST OF THE AREA THROUGH WED
AFTERNOON. RAIN CHANCES SHOULD DIMINISH WED AFTERNOON INTO WED
EVENING AS SUBSIDENCE WILL INCREASE ACROSS SOUTHWEST TX AS THE UPPER
LEVEL LOW MOVES ACROSS NORTHWEST TX WEDNESDAY.
.LONG TERM.../THURSDAY THROUGH TUESDAY NIGHT/...
LOW PRESSURE SYSTEM OVER BAJA CA WILL QUICKLY MOVE ACROSS SOUTH
CENTRAL TEXAS WED INTO THU WITH SURFACE HIGH PRESSURE TO THE EAST
MOVING SOUTHWARD OVER THE GULF WATERS AS IT INTERACTS WITH THE LOW
PRESSURE OVER WEST TEXAS. AS THIS SYSTEM LIFTS TO THE NORTHEAST...
THE SURFACE WINDS WILL RETURN TO THE SOUTHEAST ACROSS SOUTH TEXAS
AND THE GRADIENT IN RETURN WILL STRENGTHEN. EXPECT BREEZE CONDITIONS
BETWEEN 20 TO 25 MPH THURSDAY AFTERNOON. MOST OF THE MOISTURE SEEN
IN THE LAST FEW DAYS WILL DROP DRAMATICALLY ACROSS THE AREA WITH THE
BUFF SOUNDING NEAR KBRO SHOWING THE INFILTRATION OF THE DRIER AIR IN
THE UPPER AND MID LEVEL OF THE ATMOSPHERE AND A DROP IN THE PWAT
VALUES TO 1.34 INCHES AND INTO 1.10 INCHES TOWARDS THE WEST. THE
DRIER AIR MASS FROM THE RIDGE BUILDING ACROSS THE WESTERN PLAINS
WILL SET UP THAT DRIER AND WARM PATTERN FOR MOST OF THE LONG TERM
FORECAST. HIGH TEMPERATURES THURSDAY THROUGH SUNDAY WILL BE WARM AND
HUMID REACHING THE MID TO UPPER 90S THROUGH THE WEEK. ANOTHER TROUGH
DIGS SOUTHWARD ALONG BAJA CALIFORNIA AND SWING NORTHEASTWARD INTO
THE CENTRAL PLAINS SATURDAY AND SUNDAY. THE MAIN IMPACT WITH THIS
SYSTEM FOR SOUTH TEXAS WILL BE THE SE WINDS AND THE ABUNDANT WARM
TEMPERATURES ACROSS THE CWA WITH NO CONVECTION AS THE SYSTEM REMAINS
NORTH OF THE CWA. EXPECT SURFACE GRADIENT TO INCREASE WITH BREEZE TO
CONDITIONS THIS WEEKEND.
NEXT WEEK...THE TROUGH WILL CONTINUE TO MOVE NORTHEAST AND STRENGTHEN
ITS SURFACE TROUGH OVER NORTH CENTRAL PLAINS. THIS WILL CONTINUE TO
KEEP THE AREA UNDER SOUTHEAST WINDS ACROSS THE CWA. BY TUESDAY...THE
HIGH PRESSURE ALOFT BUILDS FROM THE SOUTH AND A VERY WEAK GRADIENT
AT THE SURFACE RETURNS. LOW TEMPERATURES FOR MUCH OF THE LONG TERM
FORECAST REMAIN IN THE MID 70S ACROSS THE AREA.
&&
.MARINE...TONIGHT THROUGH WEDNESDAY NIGHT...SEAS WERE NEAR 4 FEET WITH
SOUTHEAST WINDS NEAR 10 KNOTS AT BUOY020 EARLY THIS AFTERNOON. WINDS
WILL INCREASE ACROSS THE COASTAL WATERS TONIGHT AS THE PRESSURE
GRADIENT INCREASES ACROSS THE WESTERN GULF OF MEXICO. MODERATE TO
STRONG SOUTHEAST WINDS WILL PREVAIL TONIGHT WITH SCEC CONDITIONS
LIKELY OFFSHORE. THE SCEC CONDITIONS WILL PERSIST WEDNESDAY INTO WED
NIGHT...ESPECIALLY OFFSHORE...AS THE PRESSURE GRADIENT REMAINS
STRONG ACROSS THE LOWER TEXAS COAST.
THURSDAY THROUGH TUESDAY...
THE UPPER LEVEL SYSTEM OVER THE BAJA CA WILL FINALLY BEGIN TO MOVE
NORTHEAST WEDNESDAY INTO THURSDAY LIMITING THE AREA OF ANY
CONVECTION. THE SURFACE HIGH PRESSURE OVER THE SOUTHEAST PLAINS WILL
BEGIN TO SHIFT SOUTH OVER THE GULF WATERS SHIFTING WINDS ACROSS THE
GULF TOWARDS THE SE. WINDS WILL INCREASE THURSDAY AFTERNOON WITH
POSSIBLE SCA FOR MUCH OF THE DAY AND EARLY EVENING AS WINDS INCREASE.
THIS SE FLOW WILL PREVAIL FOR MUCH OF THE LONG TERM FORECAST BUT WILL
WEAKEN BY NEXT WEEK. SEAS WILL BE BETWEEN 4 TO 5 FEET OVER THE GULF
WATERS AS THERE WILL BE A LONG DURATION FETCH OVER THE GULF. THE UPPER
AND LOWER FLOW WILL WEAKEN AND KEEP THE WAVE HEIGHT 5 FEET OR LESS.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 75 83 74 86 / 40 40 20 10
BROWNSVILLE 72 84 72 89 / 40 40 20 10
HARLINGEN 72 87 73 92 / 40 40 20 10
MCALLEN 74 90 74 95 / 50 40 20 0
RIO GRANDE CITY 73 92 73 98 / 50 30 10 0
SOUTH PADRE ISLAND 75 80 75 81 / 40 40 20 10
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
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FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT
ISSUED AT 327 PM CDT TUE MAY 14 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A REMNANT
NOCTURNAL MCS DIMINISHING ACROSS NORTHERN AND CENTRAL WISCONSIN
EARLY THIS AFTERNOON AFTER IT PRODUCED LIGHT SHOWERS OVER PARTS OF
THE AREA. AT THE SURFACE...A WARM FRONT EXTENDS FROM AN AREA OF LOW
PRESSURE OVER SOUTH-CENTRAL MINNESOTA TO NORTHEAST ILLINOIS. AND A
COLD FRONT ALSO EXTENDS FROM THAT SURFACE LOW SOUTHWEST TO THE
PANHANDLE OF NEBRASKA. TEMPERATURES TO THE SOUTHWEST OF THE WARM
FRONT ARE IN THE UPPER 80S TO 100 DEGREES...BUT STILL PLENTY OF 70S
TO THE NORTH OF THE BOUNDARY. CONVECTION ALONG EITHER BOUNDARY HAS
FAILED TO DEVELOP SO FAR. THE LATEST MESOANALYSIS SUGGESTS SB CIN
HAS BEEN ERODING OVER NE IOWA WHICH APPEARS TO BE THE MOSTLY LIKELY
LOCATION OF THUNDERSTORM DEVELOPMENT LATER THIS AFTERNOON. WITH
TEMPS EXPECTED TO TOP OUT ONLY IN THE 70S TO LOWER 80S ACROSS OUR
REGION THIS AFTERNOON...HAVING A HARD TIME SEEING ANY THUNDERSTORM
DEVELOPMENT IN OUR AREA...ESPECIALLY SINCE THERE IS NO SURFACE BASED
NOR MOST UNSTABLE CAPE AS OF YET...AND DEWPOINTS ARE IN THE LOWER
40S. WILL CONSEQUENTLY REMOVE ANY THUNDERSTORM CHANCES FOR THE REST
OF THE AFTERNOON. AS THE LOW MOVES ACROSS THE REGION
TONIGHT...SMALL PRECIP CHANCES ARE THE MAIN FORECAST CONCERN.
TONIGHT...WEAK LOW PRESSURE WILL MOVE FROM FAR NW WISCONSIN ACROSS
THE UPPER PENINSULA THIS EVENING. AS THIS OCCURS...AN 850MB WARM
FRONT WILL LIFT ACROSS NE WISCONSIN EARLY IN THE EVENING WHILE THE
COLD FRONT WILL SWEEP FROM NW TO SE ACROSS THE STATE MID TO LATE
EVENING. DESPITE THE WARM SECTOR REACHING INTO CENTRAL AND
EAST-CENTRAL WISCONSIN THIS EVENING...12Z SOUNDINGS FROM MPX AND DVN
AND PROGGED SOUNDINGS ALL INDICATE AMPLE DRY AIR BELOW 600 AND
700MB. ONLY SB CAPES EXISTING ACROSS THE REGION CURRENTLY ARE OVER
SW MN AND IOWA WHERE TEMPS RANGE FROM THE UPPER 80S TO THE UPPER
90S. NOT GOING TO COME CLOSE TO REACHING THOSE READINGS THIS
EVENING...SO THE POSSIBILITY OF STORMS DEVELOPING WITHIN THE WARM
SECTOR SEEMS TOO LOW TO MENTION IN THE FORECAST. IF STORMS WERE TO
DEVELOP...THE BEST CHANCES APPEAR TO BE OVER FAR N-C TO FAR NE
WISCONSIN EARLY TO MID EVENING DUE TO SOME INDICATIONS FROM THE RUC
OF THE NOSE OF THE LLJ POINTED IN THAT DIRECTION. IN ADDITION...THERE
IS SOME ELEVATED CAPE IN THE 850-800MB LAYER AROUND 850 J/KG AND
THAT REGION WOULD BE CLOSER TO THE EDGE OF THE MID-LEVEL CAP.
CAPPING WILL REMAIN TOUGH TO OVERCOME...SINCE BUFKIT SOUNDINGS
INDICATE ELEVATED CIN UPWARDS OF 150 J/KG. WILL LEAVE AN ISOLATED
STORM IN THE FORECAST FOR THIS REGION TONIGHT...BUT
ADMITTEDLY...CHANCES ARE QUITE SMALL. IF STORMS DO FIRE...STRONG
SHEAR WOULD SUPPORT ORGANIZATION THAT COULD LEAD TO HAIL AND STRONG
GUSTY WINDS. THE THREAT OF ISOLATED STORMS WILL DEPART LATE THIS
EVENING AND SKIES WILL BECOME CLEAR OVERNIGHT. WARM EVENING TEMPS
WILL FALL INTO THE 50S FOR LOWS TONIGHT.
.LONG TERM...WEDNESDAY THROUGH TUESDAY
ISSUED AT 327 PM CDT TUE MAY 14 2013
MAIN FCST CONCERNS INCLUDE FIRE WEATHER POTENTIAL ON WEDS/THURS...THEN
PCPN TRENDS FOR THE END OF THIS WEEK AND EARLY NEXT WEEK.
A VERY DRY AIR MASS WILL RESIDE OVER THE REGION FROM WEDNESDAY INTO
THURSDAY...WITH DEEP MIXING ALLOWING TEMPERATURES TO WARM NICELY...
AND ALSO CAUSING DEW POINTS TO PLUMMET DURING THE AFTERNOONS. HIGH
TEMPERATURES WILL BE WELL INTO THE 70S BOTH DAYS.
MODELS AGREE ON A GRADUAL RETURN OF PCPN CHANCES FROM THE WEST LATE
THURSDAY NIGHT AND INTO THE WEEKEND. THE LATEST TRENDS DON`T SUPPORT
AS MUCH OF A WASHOUT FOR THE WEEKEND AS WAS PREVIOUSLY SUSPECTED...
SO POPS HAVE BEEN LOWERED A BIT AND TEMPERATURES ARE EXPECTED TO BE
A LITTLE WARMER. RIGHT NOW...THE GREATEST THREAT OF SIGNIFICANT PCPN
APPEARS TO BE DURING THE SUNDAY NIGHT THROUGH MONDAY NIGHT TIME FRAME...
AS A LOW PRESSURE SYSTEM AND ASSOCIATED FRONTAL SYSTEM MOVES THROUGH.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1230 PM CDT TUE MAY 14 2013
WEAKENING MID-LEVEL DISTURBANCE WILL GENERATE SCT VERY
LIGHT SHOWERS OVER NORTH-CENTRAL AND CENTRAL WISCONSIN THROUGH
MID-AFTERNOON...BUT CONDITIONS TO REMAIN VFR. THEN LOW PRESSURE
WILL MOVE ACROSS CENTRAL MINNESOTA AND THE UPPER PENINSULA TONIGHT.
ISOLATED STORMS ARE POSSIBLE AHEAD OF THIS LOW...MAINLY ACROSS THE
UPPER PENINSULA...BUT THINK THE AIRMASS WILL BE TOO DRY FOR
THUNDERSTORM DEVELOPMENT OVER CENTRAL AND NORTHERN WISCONSIN. LLWS
TO DEVELOPMENT THIS EVENING AHEAD OF THE LOW...AND THEN BEHIND THE
LOW AS WELL. VFR CONDITIONS EXPECTED TOMORROW WITH GUSTY NORTHWEST
WINDS.
&&
.FIRE WEATHER...
ISSUED AT 327 PM CDT TUE MAY 14 2013
TEMPERATURES IN THE 70S AND MINIMUM RELATIVE HUMIDITIES OF 20 TO 25
PERCENT IN THE SANDY SOIL AREAS CAN BE EXPECTED ON WEDS AND THURS.
NORTHWEST WINDS WILL GUST TO AROUND 30 MPH IN FAR NE WI ON WEDNESDAY
AFTERNOON...SETTING THE STAGE FOR A CRITICAL FIRE WEATHER DAY. A
FIRE WEATHER WATCH WILL BE ISSUED FOR FAR NE WI FROM NOON THROUGH
7 PM ON WEDNESDAY. WINDS WILL NOT BE AS STRONG ON THURSDAY...SO
HEADLINES SHOULD NOT BE NEEDED THEN.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR WIZ012-013-073.
&&
$$
SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......MPC
FIRE WEATHER...KIECKBUSCH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1230 PM CDT TUE MAY 14 2013
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND WEDNESDAY
ISSUED AT 436 AM CDT TUE MAY 14 2013
FORECAST CONCERNS ON TEMPERATURES TODAY AND CHANCE FOR
THUNDERSTORMS LATER THIS AFTERNOON AND THIS EVENING. HAVE TRENDED
TOWARDS GEM/NAM FOR GUIDANCE ON THIS PACKAGE. ECMWF NOW TRENDING
TOWARDS NAM WITH BETTER CHANCE FOR PCPN A BIT FURTHER SOUTH INTO
CENTRAL WI CLOSER TO WARM FRONT POSITION.
LAST EVENING SOUNDINGS SHOWS WHAT THE ISSUE WITH THIS
FORECAST...THAT BEING TOO DRY. AREA OF HIGH BASED SHOWERS WENT
THROUGH LAST NIGHT AROUND MIDNIGHT ASSOCIATED WITH STRONG WAA/850
WARM FRONT. NOTHING MORE THAN SPRINKLES SEEN. MID CLOUDINESS NOW
EXITING EASTERN WI.
FOCUS ON FAST MOVING SHORT WAVE ALONG CANADIAN BORDER AND FRONTAL
SYSTEM NOW MOVING THROUGH NORTHERN PLAINS. BY MID AFTERNOON...WARM FRONT
TO LIFT NORTH INTO SOUTHWEST WI. RATHER WARM AIR MASS TO PUSH INTO
STATE TODAY WITH 850 TEMPS INTO THE 20S OVER CENTRAL WI. WITH STEEP
MID-LEVEL LAPSE RATES BETWEEN 8 AND 9 C/KM....AND WARM
FRONT...WILL CONTINUE TO CARRY SMALL/ISOLD CHANCE FOR
THUNDERSTORMS. MODEL SOUNDINGS SUGGEST STRONG CIN THROUGH THE DAY
GIVEN DRY AIRMASS BELOW 600MB. SOUNDINGS ALSO SHOW CAPE HIGH
BASED...MAINLY ABOVE 600MB. THIS TO LEAD TO HIGH BASED
THUNDERSTORM THREAT...WHICH IF STORMS DO DEVELOP WOULD LIKELY LEAD TO
GUSTY WINDS...POSSIBLY HAIL. COLD FRONT TO PUSH THROUGH STATE BY
MIDNIGHT LEADING TO DRY FORECAST FOR REST OF NIGHT AND WEDNESDAY.
ON WEDNESDAY...GUSTY NORTHWEST WINDS BEHIND FRONT AND LOW
HUMIDITIES WITH MIXING TO 5K FEET OR HIGHER MAY LEAD TO INCREASED
FIRE DANGER.
TEMPERATURES TO BE WELL ABOVE NORM TODAY...DROPPING CLOSER TO
NORMS ON WEDNESDAY. FEW MODELS...INCLUDING HRRR SUGGEST 90 INTO
SOUTHWEST WI. HAVE BUMPED TEMPS UP SLIGHTLY THROUGHOUT CWA.
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY
ISSUED AT 436 AM CDT TUE MAY 14 2013
SURFACE HIGH PRESSURE MOVING ACROSS THE REGION AHEAD OF AN UPPER
LEVEL RIDGE SHOULD KEEP THE EARLY PART OF THE LONG TERM FORECAST
DRY. THE 00Z NAM AND 00Z GFS GENERATED SOME QPF DURING THE DAY ON
THURSDAY...BUT SINCE THE 00Z ECMWF...PREVIOUS FORECAST AND
SURROUNDING GRIDS WERE DRY...A DRY FORECAST APPEARED TO BE THE WAY
TO GO.
A SHORT WAVE AND WARM ADVECTION AHEAD OF A SURFACE TROUGH
APPROACHING FROM THE PLAINS WILL BRING A CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE AREA STARTING ON FRIDAY. VARIOUS SHORT WAVES
AHEAD OF THE MAIN UPPER TROUGH AND A SURFACE FRONTAL
BOUNDARY...COMBINED WITH A FEED OF GULF MOISTURE AHEAD OF A
DEVELOPING SURFACE LOW WILL KEEP AT LEAST A CHANCE OF SHOWERS AND
THUNDERSTORMS THROUGH THE END OF THE FORECAST PERIOD.
CLOUDS AND PRECIPITATION WILL KEEP TEMPERATURES FROM WARMING TOO
MUCH ABOVE NORMAL DURING THE DAYTIME...BUT THE SAME FACTORS SHOULD
KEEP TEMPERATURES WELL ABOVE NORMAL AT NIGHT.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1230 PM CDT TUE MAY 14 2013
WEAKENING MID-LEVEL DISTURBANCE WILL GENERATE SCT VERY
LIGHT SHOWERS OVER NORTH-CENTRAL AND CENTRAL WISCONSIN THROUGH
MID-AFTERNOON...BUT CONDITIONS TO REMAIN VFR. THEN LOW PRESSURE
WILL MOVE ACROSS CENTRAL MINNESOTA AND THE UPPER PENINSULA TONIGHT.
ISOLATED STORMS ARE POSSIBLE AHEAD OF THIS LOW...MAINLY ACROSS THE
UPPER PENINSULA...BUT THINK THE AIRMASS WILL BE TOO DRY FOR
THUNDERSTORM DEVELOPMENT OVER CENTRAL AND NORTHERN WISCONSIN. LLWS
TO DEVELOPMENT THIS EVENING AHEAD OF THE LOW...AND THEN BEHIND THE
LOW AS WELL. VFR CONDITIONS EXPECTED TOMORROW WITH GUSTY NORTHWEST
WINDS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....TE
LONG TERM......MG
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
407 PM MDT TUE MAY 14 2013
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 234 PM MDT TUE MAY 14 2013
WIDESPREAD CUMULUS HAVE DEVELOPED ALONG THE SOUTHERN ZONES THIS
AFTERNOON IN A VERY DEEP BOUNDARY LAYER. RADAR IS SHOWING SOME
WEAK SHOWERS OUT THERE...HOWEVER ITS PROBABLY MOSTLY VIRGA WITH
GUSTY WINDS. THIS ISOLATED SHOWER ACTIVITY WILL LIKELY CONTINUE
INTO THE EVENING AS THE RUC SHOWS AROUND 100-200 J/KG OF CAPE
THROUGH AROUND 03Z. LAPS ANALYSIS SHOWS A WEAK FRONT LOCATED FROM
DOUGLAS TO SIDNEY WITH HIGHER LLVL MOISTURE (DEWPOINTS IN THE 40S)
BEHIND IT AND THE MUCH DRIER AIR TO THE SOUTH OF IT. THE MODELS
HAVE THIS BOUNDARY PUSHING TO THE SOUTHWEST OVERNIGHT AND STALLING
ALONG THE LARAMIE RANGE IN THE MORNING. BOTH THE GFS AND NAM SHOW
SOME IMPRESSIVE LLVL MOISTURE BEING ADVECTED IN ON EAST-TO-
SOUTHEAST WINDS BY THE MORNING. INCREASED DEWPOINTS INTO THE LOW-
TO-MID 40S OVER THE PLAINS OF SOUTHEAST WY FROM WEDNESDAY MORNING
THROUGH THE AFTERNOON.
THE COMBINATION OF HIGHER LLVL MOISTURE AND SLIGHTLY COOLER
MIDLEVEL TEMPS ON WEDNESDAY AFTERNOON WILL RESULT IN GOOD SFC
INSTABILITY ALONG AND EAST OF THE LARAMIE RANGE. THE GFS AND NAM
BOTH SHOW LIFTED INDICES OF -3C TO -5C WHICH TRANSLATES INTO
1000-1250 J/KG OF CAPE. THE TREND OF THE MODELS HAS BEEN TO
INCREASE CONVECTIVE POTENTIAL AND QPF FOR WEDNESDAY AFTERNOON AND
EVENING. FOR THIS REASON...UP POPS INTO THE CHANCE CATEGORY OVER
THE MTNS AND PLAINS. THE DEEP LAYER SHEAR DOES NOT LOOK IMPRESSIVE
OVER THE SOUTHERN ZONES (AROUND 20 KTS)...HOWEVER FURTHER TO THE
NORTH ACROSS CONVERSE/NIOBRARA COUNTIES THE MIDLEVEL WINDS ARE
STRONGER AND 0-6KM SHEAR APPROACHES 40 KTS. SO IT LOOKS LIKE THAT
WILL BE THE REGION TO MONITOR FOR STRONGER STORMS WITH SOME SMALL
HAIL POTENTIAL. THE STORMS THAT DEVELOP OVER THE LARAMIE RANGE IN
THE EARLY AFTERNOON WILL PROGRESS EASTWARD INTO PORTIONS OF THE
WESTERN NEBRASKA PANHANDLE BY THE EARLY EVENING. TEMPS WILL BE
AROUND 10 DEGREES COOLER ON WEDNESDAY WITH THE MOIST SE SFC WINDS
AND GREATER CLOUD COVER.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 234 PM MDT TUE MAY 14 2013
THURSDAY...WEAK SHORTWAVE RIDGING ALOFT. WILL SEE ISOLATED AFTERNOON
AND EVENING THUNDERSTORMS...PRIMARILY ORIENTED ALONG THE SURFACE
TROUGH AXIS FROM EASTERN WYOMING SOUTHWARD THROUGH EASTERN COLORADO.
FRIDAY...FLOW ALOFT BACKS TO SOUTHWEST IN ADVANCE OF NEXT SHORTWAVE
TROUGH ALOFT. QUITE WARM WITH A DECENT LOW LEVEL THERMAL RIDGE
ORIENTED NORTH TO SOUTH ALONG A DECENT SURFACE TROUGH OVER OUR
COUNTIES. ISOLATED AFTERNOON AND EVENING THUNDERSTORMS ALONG A LOW
LEVEL CONVERGENCE AXIS FROM CASPER TO CHADRON TO SIDNEY...WITH AREAL
COVERAGE OF THUNDERSTORMS MINIMIZED BY WARM TEMPERATURES ALOFT
PROVIDING SIGNIFICANT CONVECTIVE INHIBITION...CIN.
SATURDAY...DECENT NEGATIVELY TILTED SHORTWAVE TROUGH ALOFT ROTATES
EASTWARD ACROSS OUR COUNTIES AND ALONG WITH ITS ASSOCIATED PACIFIC
ORIGIN COLD FRONT...EXPECT ISOLATED TO SCATTERED AFTERNOON AND
EVENING THUNDERSTORMS...MOST NUMEROUS NEAR THE MOUNTAINS DUE TO
DIFFERENTIAL HEATING AND OROGRAPHIC EFFECTS.
SUNDAY...A DEFINITE BRITISH ISLES COASTAL FEEL TYPE DAY. BRISK
WINDS...COOLER TEMPERATURES AND ISOLATED TO SCATTERED AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS ON TAP WITH NORTHWEST FLOW ALOFT
AND ENOUGH LOW AND MID LEVEL MOISTURE TO BE LIFTED BY DAYTIME
HEATING EFFECTS AND CYCLONIC FLOW ALOFT. LOW LEVEL DOWNSLOPE WINDS
WILL PRODUCE A RAIN SHADOW EFFECT FROM WHEATLAND TO CHEYENNE AND
MINIMIZE PRECIPITATION COVERAGE.
MONDAY...REFRESHINGLY COOL START TO THE TRADITIONAL WORKWEEK IN THE
WAKE OF THE RELATIVELY STRONG SHORTWAVE TROUGH PASSAGE AND WITH COOL
NORTH WINDS IN USHERING IN RELATIVELY COOL CANADIAN AIR. ISOLATED
AFTERNOON SHOWERS AND THUNDERSTORMS. TEMPERATURES WILL STILL BE NEAR
NORMAL THOUGH.
TUESDAY...TRANSITORY SHORTWAVE RIDGE ALOFT MOVES ACROSS OUR COUNTIES
AND ALONG WITH MUCH LESS LOW AND MID LEVEL MOISTURE...ONLY ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS EXPECTED.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY AFTERNOON)
ISSUED AT 402 PM MDT TUE MAY 14 2013
VFR PREVAILS.
THROUGH 02Z TONIGHT...ISOLATED HIGH BASED SHOWERS AND THUNDERSTORMS
WILL AFFECT THE LARAMIE AND CHEYENNE TAFS WITH GUSTY AND ERRATIC
WINDS AS ISOLATED SHOWERS AND THUNDERSTORMS DEVELOP OVER AND NEAR
THE SNOWY...SIERRA MADRE AND SOUTHERN LARAMIE RANGES. SHOWERS AND
THUNDERSTORMS WILL PRODUCE LOCALIZED TURBULENCE.
PERIODS OF SCATTERED TO BROKEN LOW AND MIDDLE CLOUDS AT OR ABOVE
6000 FEET AGL.
A WEAK COLD FRONT WILL MOVE SOUTHWESTWARD TO THE LEE OF THE LARAMIE
RANGE THIS EVENING. SURFACE HIGH PRESSURE WILL MOVE INTO SOUTH
DAKOTA TONIGHT PRODUCING WEAK LOW LEVEL UPSLOPE SOUTH AND
SOUTHEAST WINDS ACROSS TAF SITES. LOW LEVEL SOUTH AND SOUTHEAST
WINDS WILL STRENGTHEN WEDNESDAY MORNING...WITH SCATTERED CUMULUS
AND TOWERING CUMULUS DEVELOPMENT ALONG AND WEST OF INTERSTATE 25
BY LATE MORNING...ALONG WITH ISOLATED THUNDERSTORMS IN THIS AREA
TOWARDS NOON. SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP
OVER SOUTHEAST WYOMING AFTER NOON WEDNESDAY PRODUCING LOCALIZED
MVFR AND ERRATIC AND GUSTY WINDS TO 50 MPH.
&&
.FIRE WEATHER...
ISSUED AT 234 PM MDT TUE MAY 14 2013
RELATIVE HUMIDITY VALUES HAVE DROPPED BELOW 15 PERCENT THIS
AFTERNOON ACROSS MUCH OF THE LOWER ELEVATIONS IN A VERY WARM
AIRMASS. WINDS HAVE BECOME WEAK NORTHERLY OVER THE PANHANDLE
BEHIND A WEAK FRONT...WITH GUSTS GENERALLY BELOW 20 MPH.
TEMPERATURES ON WEDNESDAY ARE EXPECTED TO BE AROUND 10 DEGREES
COOLER WITH SOUTHEAST WINDS ALONG AND EAST OF THE LARAMIE RANGE.
THE INCREASING LOW LEVEL MOISTURE WILL PROMOTE SCATTERED SHOWERS
AND THUNDERSTORMS ON WEDNESDAY AFTERNOON AND EVENING.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...FINCH
LONG TERM...RUBIN
AVIATION...RUBIN
FIRE WEATHER...FINCH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
303 PM MDT TUE MAY 14 2013
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 234 PM MDT TUE MAY 14 2013
WIDESPREAD CUMULUS HAVE DEVELOPED ALONG THE SOUTHERN ZONES THIS
AFTERNOON IN A VERY DEEP BOUNDARY LAYER. RADAR IS SHOWING SOME
WEAK SHOWERS OUT THERE...HOWEVER ITS PROBABLY MOSTLY VIRGA WITH
GUSTY WINDS. THIS ISOLATED SHOWER ACTIVITY WILL LIKELY CONTINUE
INTO THE EVENING AS THE RUC SHOWS AROUND 100-200 J/KG OF CAPE
THROUGH AROUND 03Z. LAPS ANALYSIS SHOWS A WEAK FRONT LOCATED FROM
DOUGLAS TO SIDNEY WITH HIGHER LLVL MOISTURE (DEWPOINTS IN THE 40S)
BEHIND IT AND THE MUCH DRIER AIR TO THE SOUTH OF IT. THE MODELS
HAVE THIS BOUNDARY PUSHING TO THE SOUTHWEST OVERNIGHT AND STALLING
ALONG THE LARAMIE RANGE IN THE MORNING. BOTH THE GFS AND NAM SHOW
SOME IMPRESSIVE LLVL MOISTURE BEING ADVECTED IN ON EAST-TO-
SOUTHEAST WINDS BY THE MORNING. INCREASED DEWPOINTS INTO THE LOW-
TO-MID 40S OVER THE PLAINS OF SOUTHEAST WY FROM WEDNESDAY MORNING
THROUGH THE AFTERNOON.
THE COMBINATION OF HIGHER LLVL MOISTURE AND SLIGHTLY COOLER
MIDLEVEL TEMPS ON WEDNESDAY AFTERNOON WILL RESULT IN GOOD SFC
INSTABILITY ALONG AND EAST OF THE LARAMIE RANGE. THE GFS AND NAM
BOTH SHOW LIFTED INDICES OF -3C TO -5C WHICH TRANSLATES INTO
1000-1250 J/KG OF CAPE. THE TREND OF THE MODELS HAS BEEN TO
INCREASE CONVECTIVE POTENTIAL AND QPF FOR WEDNESDAY AFTERNOON AND
EVENING. FOR THIS REASON...UP POPS INTO THE CHANCE CATEGORY OVER
THE MTNS AND PLAINS. THE DEEP LAYER SHEAR DOES NOT LOOK IMPRESSIVE
OVER THE SOUTHERN ZONES (AROUND 20 KTS)...HOWEVER FURTHER TO THE
NORTH ACROSS CONVERSE/NIOBRARA COUNTIES THE MIDLEVEL WINDS ARE
STRONGER AND 0-6KM SHEAR APPROACHES 40 KTS. SO IT LOOKS LIKE THAT
WILL BE THE REGION TO MONITOR FOR STRONGER STORMS WITH SOME SMALL
HAIL POTENTIAL. THE STORMS THAT DEVELOP OVER THE LARAMIE RANGE IN
THE EARLY AFTERNOON WILL PROGRESS EASTWARD INTO PORTIONS OF THE
WESTERN NEBRASKA PANHANDLE BY THE EARLY EVENING. TEMPS WILL BE
AROUND 10 DEGREES COOLER ON WEDNESDAY WITH THE MOIST SE SFC WINDS
AND GREATER CLOUD COVER.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 234 PM MDT TUE MAY 14 2013
THURSDAY...WEAK SHORTWAVE RIDGING ALOFT. WILL SEE ISOLATED AFTERNOON
AND EVENING THUNDERSTORMS...PRIMARILY ORIENTED ALONG THE SURFACE
TROUGH AXIS FROM EASTERN WYOMING SOUTHWARD THROUGH EASTERN COLORADO.
FRIDAY...FLOW ALOFT BACKS TO SOUTHWEST IN ADVANCE OF NEXT SHORTWAVE
TROUGH ALOFT. QUITE WARM WITH A DECENT LOW LEVEL THERMAL RIDGE
ORIENTED NORTH TO SOUTH ALONG A DECENT SURFACE TROUGH OVER OUR
COUNTIES. ISOLATED AFTERNOON AND EVENING THUNDERSTORMS ALONG A LOW
LEVEL CONVERGENCE AXIS FROM CASPER TO CHADRON TO SIDNEY...WITH AREAL
COVERAGE OF THUNDERSTORMS MINIMIZED BY WARM TEMPERATURES ALOFT
PROVIDING SIGNIFICANT CONVECTIVE INHIBITION...CIN.
SATURDAY...DECENT NEGATIVELY TILTED SHORTWAVE TROUGH ALOFT ROTATES
EASTWARD ACROSS OUR COUNTIES AND ALONG WITH ITS ASSOCIATED PACIFIC
ORIGIN COLD FRONT...EXPECT ISOLATED TO SCATTERED AFTERNOON AND
EVENING THUNDERSTORMS...MOST NUMEROUS NEAR THE MOUNTAINS DUE TO
DIFFERENTIAL HEATING AND OROGRAPHIC EFFECTS.
SUNDAY...A DEFINITE BRITISH ISLES COASTAL FEEL TYPE DAY. BRISK
WINDS...COOLER TEMPERATURES AND ISOLATED TO SCATTERED AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS ON TAP WITH NORTHWEST FLOW ALOFT
AND ENOUGH LOW AND MID LEVEL MOISTURE TO BE LIFTED BY DAYTIME
HEATING EFFECTS AND CYCLONIC FLOW ALOFT. LOW LEVEL DOWNSLOPE WINDS
WILL PRODUCE A RAIN SHADOW EFFECT FROM WHEATLAND TO CHEYENNE AND
MINIMIZE PRECIPITATION COVERAGE.
MONDAY...REFRESHINGLY COOL START TO THE TRADITIONAL WORKWEEK IN THE
WAKE OF THE RELATIVELY STRONG SHORTWAVE TROUGH PASSAGE AND WITH COOL
NORTH WINDS IN USHERING IN RELATIVELY COOL CANADIAN AIR. ISOLATED
AFTERNOON SHOWERS AND THUNDERSTORMS. TEMPERATURES WILL STILL BE NEAR
NORMAL THOUGH.
TUESDAY...TRANSITORY SHORTWAVE RIDGE ALOFT MOVES ACROSS OUR COUNTIES
AND ALONG WITH MUCH LESS LOW AND MID LEVEL MOISTURE...ONLY ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS EXPECTED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY MORNING)
ISSUED AT 1106 AM MDT TUE MAY 14 2013
VFR PREVAILS.
THROUGH 02Z TONIGHT...ISOLATED HIGH BASED SHOWERS AND THUNDERSTORMS
MAY AFFECT THE LARAMIE AND CHEYENNE TAFS WITH GUSTY AND ERRATIC
WINDS AS ISOLATED SHOWERS AND THUNDERSTORMS DEVELOP OVER AND NEAR
THE SNOWY...SIERRA MADRE AND SOUTHERN LARAMIE RANGES. SHOWERS
AND THUNDERSTORMS WILL PRODUCE LOCALIZED TURBULENCE.
PERIODS OF SCATTERED TO BROKEN LOW AND MIDDLE CLOUDS AT OR ABOVE
6000 FEET AGL.
A WEAK COLD FRONT WILL MOVE SOUTHWESTWARD TO THE LEE OF THE LARAMIE
RANGE THIS AFTERNOON AND THIS EVENING. SURFACE HIGH PRESSURE WILL
MOVE INTO SOUTH DAKOTA TONIGHT PRODUCING WEAK LOW LEVEL UPSLOPE
SOUTH AND SOUTHEAST WINDS ACROSS TAF SITES. LOW LEVEL SOUTH AND
SOUTHEAST WINDS WILL STRENGTHEN WEDNESDAY MORNING...WITH
SCATTERED CUMULUS AND TOWERING CUMULUS DEVELOPMENT ALONG AND
WEST OF INTERSTATE 25 BY LATE MORNING...ALONG WITH ISOLATED
THUNDERSTORMS IN THIS AREA TOWARDS NOON.
&&
.FIRE WEATHER...
ISSUED AT 234 PM MDT TUE MAY 14 2013
RELATIVE HUMIDITY VALUES HAVE DROPPED BELOW 15 PERCENT THIS
AFTERNOON ACROSS MUCH OF THE LOWER ELEVATIONS IN A VERY WARM
AIRMASS. WINDS HAVE BECOME WEAK NORTHERLY OVER THE PANHANDLE
BEHIND A WEAK FRONT...WITH GUSTS GENERALLY BELOW 20 MPH.
TEMPERATURES ON WEDNESDAY ARE EXPECTED TO BE AROUND 10 DEGREES
COOLER WITH SOUTHEAST WINDS ALONG AND EAST OF THE LARAMIE RANGE.
THE INCREASING LOW LEVEL MOISTURE WILL PROMOTE SCATTERED SHOWERS
AND THUNDERSTORMS ON WEDNESDAY AFTERNOON AND EVENING.
&&
.HYDROLOGY...
ISSUED AT 234 PM MDT TUE MAY 14 2013
TEMPERATURES THIS AFTERNOON HAVE CLIMBED INTO THE 60S ACROSS THE
SNOWY AND SIERRA MADRE RANGES. LATEST RIVER GAGES ON THE
RIVERS IN CARBON AND ALBANY COUNTY ARE SHOWING A STEADY INCREASE
IN RIVER LEVELS...PEAKING OUT DURING THE LATE EVENING. THOUGH
RIVERS ARE EXPECTED TO STAY WITHIN THEIR BANKS...OUTDOOR
ENTHUSIASTS OR PERSONS LIVING NEAR THESE RIVERS IN SOUTHEAST
WYOMING NEED TO MONITOR RIVERS AND STREAMS NEAR THEIR CAMPSITES OR
HOMES IN CASE RAPID RISES DO OCCUR. THERE IS STILL PLENTY OF SNOW
PACK THAT WILL MELT OVER THE NEXT FEW DAYS AS TEMPERATURES WILL
REMAIN ABOVE NORMAL THROUGH FRIDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...FINCH
LONG TERM...RUBIN
AVIATION...RUBIN
FIRE WEATHER...FINCH
HYDROLOGY...FINCH