Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/01/13
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
1215 PM PDT SAT MAR 30 2013
UPDATED CLIMATE SECTION
.DISCUSSION...AS OF 8:29 AM PDT SATURDAY...IR SATELLITE AND KMUX
PRETTY MUCH SAY IT ALL...A STORM SYSTEM IS APPROACHING THE BAY
AREA WITH A MIXTURE OF CLOUDS AND SHOWERS. AS MENTIONED ON THE
PREVIOUS DISCUSSION...MUCH OF THE SHORT TERM WEATHER CONCERNS WILL
BE ASSOCIATED WITH A SFC LOW NEAR 34N/132W. KMUX RADAR IMAGERY
CONTINUES TO INDICATE SHOWER ACTIVITY OFF THE NORTH BAY COAST AND
PARTS OF THE NORTH BAY. HOWEVER...THESE SHOWERS ARE BEING DETECTED AT
ROUGHLY 10-12K FEET AGL. THE MORNING KOAK SOUNDING SHOWS A MOIST
LAYER AROUND 10K FEET...BUT A LARGE DRY POCKET OF AIR JUST BELOW
10K FEET. THE ECHOES DETECTED ON RADAR ARE PROBABLY NOT REACHING
THE GROUND. THIS IS FURTHER CONFIRMED BY THE LACK OF SFC REPORTS
FOR MEASURABLE PRECIP. THAT BEING SAID...PATCHY STRATUS DOES EXIST
ALONG THE COAST WITH LIGHT DRIZZLE BEING REPORTED. ALSO...DURING
THE MORNING HOURS A FEW SPRINKLES MAY BE POSSIBLE WITH THE RADAR
ECHOES...BUT WIDESPREAD SHOWERS SEEMS UNLIKELY.
NO UPDATE PLANNED AT THIS TIME. WILL CONTINUE TO MONITOR
DEVELOPING SHOWERS AND APPROACHING STORM SYSTEM. THERE WILL BE A
BETTER CHANCE FOR SHOWERS LATE THIS AFTERNOON AND EVENING AS THE
PARENT SFC LOW MOVES CLOSER TO THE COAST. IN FACT...SOME OF THE
12Z MODEL GUIDANCE...INCLUDING THE RAP AND HRRR...KEEP THE BULK OF
THE MOISTURE OFF THE COAST UNTIL AFTER 00Z SUNDAY. THE OTHER
INTERESTING ITEM OF NOTE...THE NAM12 FCST SOUNDINGS STILL DEVELOP
CONVECTION OVER THE NORTH BAY THIS AFTERNOON...CAPE 500 J/KG WITH
LITTLE CIN AND LI/S MINUS 3. NOT TOTALLY BUYING OFF ON THIS YET
GIVEN THE CLOUD COVER/WEAK MARINE LAYER AND LACK OF SOLAR HEATING
EXPECTED. BETTER CHANCE FOR CONVECTION ON SUNDAY AS THE UPPER LOW
AND COLD AIR ALOFT PASS OVERHEAD.
THE BULK OF THE RAIN STILL LOOKS TO OCCUR DURING THE OVERNIGHT
HOURS TONIGHT AND SUNDAY. HIGH PRESSURE BUILDS OVER THE REGION ON
MONDAY AND ANY LINGERING SHOWERS WILL DIMINISH. NAILING DOWN
PRECIP AMOUNTS IS SOMEWHAT PROBLEMATIC GIVEN THE CONVECTIVE NATURE
OF PRECIP TONIGHT THROUGH EARLY MONDAY. FOR NOW...BEST GUESS
CONTINUES INDICATE A FEW TENTHS OVER THE LOWER ELEVATIONS AND UP
TO ONE INCH OVER THE COASTAL MOUNTAINS.
PREVIOUS...THE NEXT RAIN CHANCES WILL OCCUR WEDNESDAY NIGHT AND
THURSDAY AS AN UPPER TROUGH MOVES ONTO THE COAST...WITH ANOTHER
SYSTEM POSSIBLE BY NEXT WEEKEND.
&&
.AVIATION...AS OF 11:45 AM PDT SATURDAY...FOR 18Z TAFS. SOUTHERLY
FLOW ASSOCIATED WITH UPPER LOW IS KEEPING STUBBORN LOW CLOUDS
AROUND THE REGION ALONG WITH MID AND HIGH DECKS. AIRPORT LEAST
IMPACTED CONTINUES TO BE SAN JOSE WHILE MVFR CLOUD DECKS CONTINUE
TO COME IN AND OUT OF KSFO AND KOAK WITH SHOWERS AND IFR
CONDITIONS IN THE NORTH BAY. IN GENERAL LOOK FOR LIFTING CLOUD
DECKS THIS AFTERNOON AND EVENING AS THE AREA WILL BE IN A LULL
REGION BEFORE THE NEXT SPOKE OF ENERGY ROTATES ONSHORE AFTER 06Z.
VICINITY OF KSFO...MVFR CONDITIONS CONTINUE THROUGH 21Z BUT WITH
CIG HEIGHTS CONTINUING TO LIFT THROUGH THE LATE AFTERNOON AND
EVENING HOURS. NEXT BAND OF SHOWERS LOOKS TO HOLD OFF UNTIL
SOMETIME AROUND MIDNIGHT.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO BUT WITH LESS LOW CLOUDS
EXPECTED SOUTH OF THE BRIDGE AND TOWARDS KSJC THIS AFTERNOON AND EVENING.
MONTEREY BAY AREA TERMINALS...STUBBORN CIGS CONTINUE TO IMPACT
KMRY AND KSNS BUT WITH CLEAR SKIES JUST WEST OF KMRY AND OVER THE
OCEAN EXPECTED TO DEVELOP BY LATER THIS AFTERNOON. -SHRA EXPECTED
TO DEVELOP LATER THIS EVENING NEAR KMRY IN SW FLOW AHEAD OF NEXT
UPPER DISTURBANCE.
&&
.CLIMATE...DOWNTOWN SAN FRANCISCO IS ON TRACK TO HAVE ITS DRIEST
JANUARY THROUGH MARCH ON RECORD. THE CITY HAS A CONTINUAL DATA SET
GOING BACK TO 1850, SO IT IS NOTABLE WHEN RECORDS ARE BROKEN
THERE. AS OF NOON TODAY, ONLY 1.73" OF RAIN HAS BEEN RECORDED.
THIS AMOUNT IS NEARLY 1.5" BELOW THE CURRENT JANUARY THROUGH MARCH
RECORD OF 3.20" SET ALL OF THE WAY BACK IN 1850. THE AVERAGE
RAINFALL FOR THE SAME TIME PERIOD IS 12.22". WE WILL PROVIDE
UPDATED NUMBERS AS RAIN FALLS IN SAN FRANCISCO THIS WEEKEND.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...NONE.
$$
PUBLIC FORECAST: MM
AVIATION/MARINE: RWW
CLIMATE: BELL
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AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
1145 AM PDT SAT MAR 30 2013
.DISCUSSION...AS OF 8:29 AM PDT SATURDAY...IR SATELLITE AND KMUX
PRETTY MUCH SAY IT ALL...A STORM SYSTEM IS APPROACHING THE BAY
AREA WITH A MIXTURE OF CLOUDS AND SHOWERS. AS MENTIONED ON THE
PREVIOUS DISCUSSION...MUCH OF THE SHORT TERM WEATHER CONCERNS WILL
BE ASSOCIATED WITH A SFC LOW NEAR 34N/132W. KMUX RADAR IMAGERY
CONTINUES TO INDICATE SHOWER ACTIVITY OFF THE NORTH BAY COAST AND
PARTS OF THE NORTH BAY. HOWEVER...THESE SHOWERS ARE BEING DETECTED AT
ROUGHLY 10-12K FEET AGL. THE MORNING KOAK SOUNDING SHOWS A MOIST
LAYER AROUND 10K FEET...BUT A LARGE DRY POCKET OF AIR JUST BELOW
10K FEET. THE ECHOES DETECTED ON RADAR ARE PROBABLY NOT REACHING
THE GROUND. THIS IS FURTHER CONFIRMED BY THE LACK OF SFC REPORTS
FOR MEASURABLE PRECIP. THAT BEING SAID...PATCHY STRATUS DOES EXIST
ALONG THE COAST WITH LIGHT DRIZZLE BEING REPORTED. ALSO...DURING
THE MORNING HOURS A FEW SPRINKLES MAY BE POSSIBLE WITH THE RADAR
ECHOES...BUT WIDESPREAD SHOWERS SEEMS UNLIKELY.
NO UPDATE PLANNED AT THIS TIME. WILL CONTINUE TO MONITOR
DEVELOPING SHOWERS AND APPROACHING STORM SYSTEM. THERE WILL BE A
BETTER CHANCE FOR SHOWERS LATE THIS AFTERNOON AND EVENING AS THE
PARENT SFC LOW MOVES CLOSER TO THE COAST. IN FACT...SOME OF THE
12Z MODEL GUIDANCE...INCLUDING THE RAP AND HRRR...KEEP THE BULK OF
THE MOISTURE OFF THE COAST UNTIL AFTER 00Z SUNDAY. THE OTHER
INTERESTING ITEM OF NOTE...THE NAM12 FCST SOUNDINGS STILL DEVELOP
CONVECTION OVER THE NORTH BAY THIS AFTERNOON...CAPE 500 J/KG WITH
LITTLE CIN AND LI/S MINUS 3. NOT TOTALLY BUYING OFF ON THIS YET
GIVEN THE CLOUD COVER/WEAK MARINE LAYER AND LACK OF SOLAR HEATING
EXPECTED. BETTER CHANCE FOR CONVECTION ON SUNDAY AS THE UPPER LOW
AND COLD AIR ALOFT PASS OVERHEAD.
THE BULK OF THE RAIN STILL LOOKS TO OCCUR DURING THE OVERNIGHT
HOURS TONIGHT AND SUNDAY. HIGH PRESSURE BUILDS OVER THE REGION ON
MONDAY AND ANY LINGERING SHOWERS WILL DIMINISH. NAILING DOWN
PRECIP AMOUNTS IS SOMEWHAT PROBLEMATIC GIVEN THE CONVECTIVE NATURE
OF PRECIP TONIGHT THROUGH EARLY MONDAY. FOR NOW...BEST GUESS
CONTINUES INDICATE A FEW TENTHS OVER THE LOWER ELEVATIONS AND UP
TO ONE INCH OVER THE COASTAL MOUNTAINS.
PREVIOUS...THE NEXT RAIN CHANCES WILL OCCUR WEDNESDAY NIGHT AND
THURSDAY AS AN UPPER TROUGH MOVES ONTO THE COAST...WITH ANOTHER
SYSTEM POSSIBLE BY NEXT WEEKEND.
&&
.AVIATION...AS OF 11:45 AM PDT SATURDAY...FOR 18Z TAFS. SOUTHERLY
FLOW ASSOCIATED WITH UPPER LOW IS KEEPING STUBBORN LOW CLOUDS
AROUND THE REGION ALONG WITH MID AND HIGH DECKS. AIRPORT LEAST
IMPACTED CONTINUES TO BE SAN JOSE WHILE MVFR CLOUD DECKS CONTINUE
TO COME IN AND OUT OF KSFO AND KOAK WITH SHOWERS AND IFR
CONDITIONS IN THE NORTH BAY. IN GENERAL LOOK FOR LIFTING CLOUD
DECKS THIS AFTERNOON AND EVENING AS THE AREA WILL BE IN A LULL
REGION BEFORE THE NEXT SPOKE OF ENERGY ROTATES ONSHORE AFTER 06Z.
VICINITY OF KSFO...MVFR CONDITIONS CONTINUE THROUGH 21Z BUT WITH
CIG HEIGHTS CONTINUING TO LIFT THROUGH THE LATE AFTERNOON AND
EVENING HOURS. NEXT BAND OF SHOWERS LOOKS TO HOLD OFF UNTIL
SOMETIME AROUND MIDNIGHT.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO BUT WITH LESS LOW CLOUDS
EXPECTED SOUTH OF THE BRIDGE AND TOWARDS KSJC THIS AFTERNOON AND EVENING.
MONTEREY BAY AREA TERMINALS...STUBBORN CIGS CONTINUE TO IMPACT
KMRY AND KSNS BUT WITH CLEAR SKIES JUST WEST OF KMRY AND OVER THE
OCEAN EXPECTED TO DEVELOP BY LATER THIS AFTERNOON. -SHRA EXPECTED
TO DEVELOP LATER THIS EVENING NEAR KMRY IN SW FLOW AHEAD OF NEXT
UPPER DISTURBANCE.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...NONE.
$$
PUBLIC FORECAST: MM
AVIATION/MARINE: RWW
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AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
831 AM PDT SAT MAR 30 2013
.DISCUSSION...AS OF 8:29 AM PDT SATURDAY...IR SATELLITE AND KMUX
PRETTY MUCH SAY IT ALL...A STORM SYSTEM IS APPROACHING THE BAY
AREA WITH A MIXTURE OF CLOUDS AND SHOWERS. AS MENTIONED ON THE
PREVIOUS DISCUSSION...MUCH OF THE SHORT TERM WEATHER CONCERNS WILL
BE ASSOCIATED WITH A SFC LOW NEAR 34N/132W. KMUX RADAR IMAGERY
CONTINUES TO INDICATE SHOWER ACTIVITY OFF THE NORTH BAY COAST AND
PARTS OF THE NORTH BAY. HOWEVER...THESE SHOWERS ARE BEING DETECTED AT
ROUGHLY 10-12K FEET AGL. THE MORNING KOAK SOUNDING SHOWS A MOIST
LAYER AROUND 10K FEET...BUT A LARGE DRY POCKET OF AIR JUST BELOW
10K FEET. THE ECHOES DETECTED ON RADAR ARE PROBABLY NOT REACHING
THE GROUND. THIS IS FURTHER CONFIRMED BY THE LACK OF SFC REPORTS
FOR MEASURABLE PRECIP. THAT BEING SAID...PATCHY STRATUS DOES EXIST
ALONG THE COAST WITH LIGHT DRIZZLE BEING REPORTED. ALSO...DURING
THE MORNING HOURS A FEW SPRINKLES MAY BE POSSIBLE WITH THE RADAR
ECHOES...BUT WIDESPREAD SHOWERS SEEMS UNLIKELY.
NO UPDATE PLANNED AT THIS TIME. WILL CONTINUE TO MONITOR
DEVELOPING SHOWERS AND APPROACHING STORM SYSTEM. THERE WILL BE A
BETTER CHANCE FOR SHOWERS LATE THIS AFTERNOON AND EVENING AS THE
PARENT SFC LOW MOVES CLOSER TO THE COAST. IN FACT...SOME OF THE
12Z MODEL GUIDANCE...INCLUDING THE RAP AND HRRR...KEEP THE BULK OF
THE MOISTURE OFF THE COAST UNTIL AFTER 00Z SUNDAY. THE OTHER
INTERESTING ITEM OF NOTE...THE NAM12 FCST SOUNDINGS STILL DEVELOP
CONVECTION OVER THE NORTH BAY THIS AFTERNOON...CAPE 500 J/KG WITH
LITTLE CIN AND LI/S MINUS 3. NOT TOTALLY BUYING OFF ON THIS YET
GIVEN THE CLOUD COVER/WEAK MARINE LAYER AND LACK OF SOLAR HEATING
EXPECTED. BETTER CHANCE FOR CONVECTION ON SUNDAY AS THE UPPER LOW
AND COLD AIR ALOFT PASS OVERHEAD.
THE BULK OF THE RAIN STILL LOOKS TO OCCUR DURING THE OVERNIGHT
HOURS TONIGHT AND SUNDAY. HIGH PRESSURE BUILDS OVER THE REGION ON
MONDAY AND ANY LINGERING SHOWERS WILL DIMINISH. NAILING DOWN
PRECIP AMOUNTS IS SOMEWHAT PROBLEMATIC GIVEN THE CONVECTIVE NATURE
OF PRECIP TONIGHT THROUGH EARLY MONDAY. FOR NOW...BEST GUESS
CONTINUES INDICATE A FEW TENTHS OVER THE LOWER ELEVATIONS AND UP
TO ONE INCH OVER THE COASTAL MOUNTAINS.
PREVIOUS...THE NEXT RAIN CHANCES WILL OCCUR WEDNESDAY NIGHT AND THURSDAY AS
AN UPPER TROUGH MOVES ONTO THE COAST...WITH ANOTHER SYSTEM
POSSIBLE BY NEXT WEEKEND.
&&
.AVIATION...AS OF 4:47 AM PDT SATURDAY...CURRENTLY THE IR
SATELLITE IMAGE IS SHOWING MID TO HIGH CLOUDS AND SOUTHERLY FLOW
OVER THE FORECAST AREA. THE GOES IFR PROB PROD IS INDICATING IFR
PROB GREATER THAN 60% OVER PORTIONS OF SAN FRANCISCO BAY WITH KOAK
OB INDICATING BKN005. SOUTHERLY FLOW SHOULD HELP TO KEEP THE LOW
CIGS OUT OF KSFO BUT THERE MAY BE SOME IFR CIGS OVER THE APPROACH.
RUNWAYS SHOULD REMAIN DRY THIS MORNING WITH SHOWERS EXPECTED TO
DEVELOP LATER THIS EVENING.
VICINITY OF KSFO...VFR IS ANTICIPATED TODAY WITH A LOW PROBABILITY
OF IFR CIGS THIS MORNING. IF IFR DOES DEVELOP CONDITIONS SHOULD
IMPROVE NO LATER THAN 1700Z. GENERALLY LIGHT WINDS WILL INCREASE
OUT OF THE SOUTHWEST TO 10 TO 12 KT BY 2100Z.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO WITH A HIGHER PROB OF IFR
CIGS THIS MORNING. IF IFR CIGS DO DEVELOP CONDITIONS SHOULD
IMPROVE BY 1700Z.
MONTEREY BAY AREA TERMINALS...LIFR CIGS THIS MORNING WILL IMPROVE
TO IFR BY 1700Z WITH CONTINUED IMPROVEMENT TO VFR BY 2000Z.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...NONE.
$$
PUBLIC FORECAST: MM
AVIATION/MARINE: LARRY
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AREA FORECAST DISCUSSION
NWS TAUNTON MA
706 AM EDT SAT MAR 30 2013
.SYNOPSIS...
HIGH PRESSURE WILL BRING DRY AND MILD WEATHER TO THE REGION TODAY
INTO MOST OF SUNDAY AFTERNOON. AN APPROACHING COLD FRONT WILL BRING
A PERIOD OF SHOWERS TO THE REGION SUN NIGHT WITH EVEN THE RISK FOR
AN ISOLATED THUNDERSTORM. ANOTHER COLD FRONT WILL BRING COLDER
WEATHER INTO THE MID PART OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
7 AM UPDATE...
MID LVL SHORTWAVE IS NOW BEGINNING TO SHIFT E OF THE FORECAST AREA
EARLY THIS MORNING. THIS IS ALLOWING BOTH SOME LOW TO MID STRATO-
CU AND SOME LIGHT SHOWERS OVER THE ISLANDS TO BEGIN SHIFTING E OF
THE AREA...GIVING WAY TO MOSTLY SKC CONDITIONS ACROSS MUCH OF THE
INTERIOR. THE TREND WILL BE TOWARD THIS CLEARING EVEN IN THE E.
WILL STILL NEED TO MONITOR FOR THE SLIGHT CHANCE OF AN AFTERNOON
SHOWER PARTICULARLY IN THE SE...BUT IT APPEARS MUCH OF THE AY WILL
BE DRY. THEREFORE WILL CONTINUE WITH NIL POPS. ADJUSTED SKIES
TOWARD LATEST RAP AND ALSO UPDATED TEMPS AND DWPTS TO BRING THEM
UP TO CURRENT TRENDS.
PREVIOUS DISCUSSION...
A MID LEVEL SHORTWAVE WAS RESULTING IN A FEW LINGERING
SPRINKLES/LIGHT SHOWERS ACROSS THE CAPE AND ISLANDS VERY EARLY THIS
MORNING. THIS ACTIVITY SHOULD EXIT THE REGION BY DAYBREAK.
OTHERWISE...A PARTLY TO MOSTLY SUNNY AND MILD DAY IS ON TAP FOR THE
REGION. ALTHOUGH 850 MB TEMPS ARE AROUND -3C...DRY NORTHWEST FLOW
AND A WELL MIXED ATMOSPHERE WILL YIELD A SUPER ADIABATIC ATMOSPHERE.
HIGH TEMPS SHOULD RISE INTO THE MID TO UPPER 50S...AND ITS NOT OUT
OF THE QUESTION THAT A FEW SPOTS HIT THE 60 DEGREE MARK. GIVEN THE
RELATIVELY WEAK PRESSURE GRADIENT...SEA BREEZES MAY DEVELOP ALONG
THE VERY IMMEDIATE COAST RESULTING IN LOCALIZED COOLER CONDITIONS IN
THOSE REGIONS DURING AFTERNOON.
WE KEPT THE FORECAST DRY AS UPPER LEVEL TROUGH IS MOVING EAST AND
ALLOWING FOR RISING HEIGHT FIELDS IN SOUTHERN NEW ENGLAND. GUESS
THERE IS STILL A LOW RISK OF AN ISOLATED SPOT SHOWER NEAR THE
SOUTHEAST NEW ENGLAND COAST THIS AFTERNOON...BUT NOT WORTH
MENTIONING IN THE FORECAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
TONIGHT...
A RIDGE OF HIGH PRESSURE BUILDS OVER THE REGION. THIS WILL RESULT
IN MAINLY CLEAR SKIES/LIGHT WINDS AND A GOOD NIGHT OF RADIATIONAL
COOLING. DESPITE THE MILD DAY...LOW TEMPS SHOULD FALL WELL DOWN
INTO THE 20S TO LOWER 30S IN MOST LOCALES BY DAYBREAK SUN.
SUNDAY AND SUNDAY NIGHT...
THE RIDGE OF HIGH PRESSURE MOVES OFF THE
COAST EARLY ON SUN...ALLOWING FOR A SOUTHERLY FLOW OF MILD AIR TO
WORK INTO THE REGION. WHILE CLOUDS WILL INCREASE DURING THE
AFTERNOON FROM WEST TO EAST...A FAIR AMOUNT OF SUNSHINE IS EXPECTED
FOR THE FIRST PART OF THE DAY. THIS SHOULD ALLOW HIGH TEMPS TO
REACH INTO THE UPPER 50S TO AROUND 60 NORTHWEST OF BOS TO PVD LINE.
SOUTHERLY FLOW OFF THE OCEAN WILL RESULT IN TEMPS A BIT COOLER
SOUTHEAST OF THIS REGION...WITH HIGHS HELD DOWN INTO THE UPPER 40S
AND LOWER 50S ACROSS THE CAPE/ISLANDS.
EXPECT THE WEATHER TO PRETTY MUCH REMAIN DRY DURING THE DAY SUNDAY.
A COLD FRONT APPROACHING FROM THE WEST WILL BRING A BAND OF SHOWERS
ACROSS THE REGION SUNDAY NIGHT FOR A FEW HOURS. THERE MAY BE JUST
ENOUGH ELEVATED INSTABILITY FOR A FEW EMBEDDED THUNDERSTORMS...WITH
THE BEST CHANCE ALONG THE SOUTHEAST NEW ENGLAND COAST. THE MODELS
INDICATE THAT TOTAL TOTALS MAY RISE INTO THE MID 50S WITH SHOWALTERS
DROPPING TO AROUND ZERO...SO HAVE INSERTED SOME ISOLATED THUNDER
INTO THE FORECAST. THE FRONT WILL BE FAST MOVING SO SHOWERS SHOULD
ONLY LAST A FEW HOURS IN A GIVEN LOCATION...WITH RAINFALL AMOUNTS
LESS THAN A HALF INCH.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
* WARMER TEMPERATURES EXPECTED MON THEN COOLING
* COOLER WEATHER MOVES BACK IN TUES AND WED
* WARMING THU AND FRI...BUT WILL HAVE TO WATCH OCEAN STORM
OVERVIEW AND MODEL PREFERENCES...
30/00Z MODEL GUIDANCE SUITE CONTINUES TO SHOW REASONABLY GOOD
AGREEMENT THROUGH MUCH OF THE LONG TERM AND HAS BEEN DELAYING THE
BREAKDOWN OF BLOCKING GREENLAND RIDGE. CPC CONTINUES TO SHOW A
NEGATIVE AO PATTERN NOW INTO EARLY APRIL...WHICH SUPPORTS THIS
THINKING. THE RIDGE LOOKS TO REMAIN IN PLACE THROUGH MUCH OF THE
COMING WEEK AND THEREFORE HOLDS CUTOFF LOW PRES IN VICINITY OF
NEWFOUNDLAND AND LABRADOR. THIS SETUP SUGGESTS TEMPERATURES
GENERALLY REMAIN ON THE COOL SIDE OF NORMAL FOR MUCH OF THE WEEK.
OPERATIONAL GFS AND ECMWF ARE BOTH IN AGREEMENT HERE...BUT THE
ECMWF CONTINUES TO BE A BIT COLDER...AND SEEMS TO HAVE BEEN MORE
PERSISTENT. THEREFORE...WILL CONTINUE WITH USING IT AS A BASELINE.
DETAILS...
MON INTO MON NIGHT...
FOLLOWING OCCLUSION IN THE MORNING EXPECT A BRIEF LULL IN
PRECIPITATION LIKELY UNTIL MID TO LATE AFTERNOON THANKS TO A
FAIRLY ROBUST DRY SLOT IN ADVANCE OF AN ARCTIC COLD FRONT. THIS
SECONDARY FRONT IS EXPECTED TO MOVE THROUGH BETWEEN 18Z AND 00Z
TUE...WITH SOME ISOLATED RAIN SHOWERS INITIALLY. GIVEN A FAIR
AMOUNT OF COLD DRY AIR ADVECTING IN RAPIDLY...MAY ACTUALLY SEE A
BRIEF CHANGE OVER TO SOME SNOW SHOWERS TOWARD THE END OF THE DAY.
AT THIS POINT...GIVEN THE WARM START /H85 TEMPS START HIGHER THAN
0C/ WILL LIKELY SEE LITTLE ACCUMULATION IF ANY UNLESS A BRIEF
HEAVIER SNOW SHOWER OCCURS IN WHICH DYNAMIC COOLING IS ENOUGH FOR
BETTER SNOW DEVELOPMENT. MAY SEE SOME WIND GUSTS EXCEEDING 30 MPH
ESPECIALLY WITH THE FRONT...BUT EXPECT THAT MOST GUSTS SHOULD
REMAIN BELOW WIND ADVISORY CRITERIA.
TUE AND WED...
ARCTIC FRONT MOVES FURTHER OFFSHORE TUE AND DRY HIGH PRES BEGINS
TO BUILD IN FROM THE W. THIS ALLOWS THE CONTINUED COOL NW FLOW
OVER THE REGION. MAY SEE SOME CLOUDS AND LIGHT SHOWERS
PARTICULARLY IN THE NW THANKS TO DECENT MID LVL COLD
ADVECTION...BUT OTHERWISE THE BEGINNING OF A MOSTLY DRY PERIOD IS
EXPECTED. EXPECTING THE CONTINUATION OF SOME 20 TO 30 MPH WIND
GUSTS PARTICULARLY DURING THE DAY...SO IT WILL BE BLUSTERY. H85
TEMPERATURES ARE EXPECTED TO HOVER CLOSE TO ABOUT -10C...SO
TEMPERATURES IN THE LOW TO MID 40S ARE LIKELY GIVEN THE EARLY
APRIL SUN.
THU INTO FRI...
HIGH PRES BUILDS OVER THE REGION DURING THIS PERIOD. AT THIS
POINT...MOST LONG RANGE GUIDANCE SUGGESTS THE BLOCKING HIGH SHIFTS
INTO THE MARITIMES AND SETS UP SUCH THAT SRN STREAM WAVE STAYS TOO
FAR OFFSHORE TO AFFECT THE REGION. HOWEVER...THIS WILL NEED TO BE
MONITORED SHOULD THE BLOCK SHIFT TO THE N...WHICH MAY ALLOW THIS
COASTAL LOW TO AFFECT THE REGION. THE 00Z ECMWF DOES SHOW THIS
MAKING A CLOSE ENOUGH PASS...SUCH THAT PRECIP MAY FALL...HOWEVER
WILL CONTINUE TO HOLD THE DRY TREND CONSIDERING THIS IS THE FIRST
RUN AND MANY OF ITS ENSEMBLE MEMBERS CONTINUE TO BE FURTHER
OFFSHORE. EXPECTING A SLIGHT MODERATING TREND IN TEMPERATURES AS
HIGH PRES SLIDES E AND SOME WEAK WARM ADVECTION DEVELOPS.
NEXT WEEKEND...
WHILE THIS WILL BE DEPENDENT SOMEWHAT ON EXACTLY WHAT THE SRN
STREAM WAVE DOES...IT APPEARS THAT SOME HIGH PRES WILL BUILD BACK
OVER THE REGION BY NEXT WEEKEND. ALLOWING FOR A GENERAL DRYING
TREND.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...HIGH CONFIDENCE THROUGH SUNDAY AFTERNOON. MODERATE
CONFIDENCE SUNDAY NIGHT.
VFR CONDITIONS TODAY THROUGH SUNDAY AFTERNOON.
OTHERWISE...MVFR CONDITIONS BEGIN WITH A BAND OF RAIN MOVING FROM
W TO E BY SUN AFTERNOON...MVFR WILL LIKELY ACCOMPANY THIS RAIN
ALTHOUGH CAN/T RULE OUT A BRIEF PERIOD OF IFR. THERE ALSO MAY BE
A FEW EMBEDDED THUNDERSTORMS WITH THE BEST CHANCE ALONG THE
COASTAL PLAIN DURING THE EVENING AND EARLY OVERNIGHT SUN NIGHT..
KBOS TAF...HIGH CONFIDENCE IN VFR CONDITIONS TODAY AND TONIGHT.
WILL HAVE TO MONITOR FOR ANOTHER WEAK SEA BREEZE FOR A COUPLE OF
HOURS THIS AFTERNOON. WILL TIME THIS IN THE TAF...AND WILL HAVE TO
MONITOR THE STRENGTH OF THE SFC WIND...SHOULD IT DIMINISH THIS
AFTERNOON THE CHANCE OF THE SEA BREEZE COMING ON SHORE IS HIGHER.
KBDL TAF...HIGH CONFIDENCE IN TAF TODAY AND TONIGHT.
OUTLOOK...MONDAY THROUGH WEDNESDAY...
MONDAY...MODERATE CONFIDENCE IN MAINLY VFR CONDITIONS. HOWEVER...A
SECONDARY FRONT MAY BRING ISOLATED MVFR CONDITIONS LATE DAY MON.
TUESDAY AND WEDNESDAY...HIGH CONFIDENCE.
MAINLY VFR.
&&
.MARINE...
HIGH CONFIDENCE THROUGH SUNDAY AFTERNOON THAT WINDS/SEAS WILL REMAIN
BELOW SCA THRESHOLDS WITH A RELATIVELY WEAK PRESSURE GRADIENT IN
PLACE. AN APPROACHING COLD FRONT WILL LIKELY BRING A PERIOD OF
SOUTHERLY SCA WIND GUSTS AND SEAS TO THE WATERS SUNDAY NIGHT. SINCE
ITS A 4TH PERIOD EVENT...IT WAS TOO EARLY TO ISSUE ANY MARINE
HEADLINES.
OUTLOOK...MONDAY THROUGH WEDNESDAY...
MODERATE TO HIGH CONFIDENCE.
AFTER A SERIES OF FRONTS SUN NIGHT AND MONDAY...EXPECT NW WINDS TO
BUILD AND MAINTAIN AROUND 25 TO 30 KT AT TIMES FROM LATE DAY MON
INTO WED. SEAS MAY DROP A BIT ESPECIALLY ON NEAR SHORE
WATERS...BUT WILL LIKELY REMAIN ABOVE 5 FT OVER OUT WATERS. SMALL
CRAFT ADVISORIES ARE LIKELY FROM MON INTO WED.
LOW PROBABILITY OF SOME ISOLATED GALE FORCE WIND GUSTS DURING THIS
PERIOD AS WELL.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...FRANK/DOODY
NEAR TERM...FRANK/DOODY
SHORT TERM...FRANK
LONG TERM...DOODY
AVIATION...FRANK/DOODY
MARINE...FRANK/DOODY
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
355 AM EDT SAT MAR 30 2013
.SYNOPSIS...
07Z WATER VAPOR AND H4 RAP ANALYSIS CONTINUES TO SHOW A GENERALLY
BENIGN UPPER LEVEL PATTERN IN PLACE OVER THE CONUS THIS MORNING.
CONVERGENT FLOW ARRIVES OVER THE PACIFIC NORTHWEST AND THEN FORMS A
GENERAL WEST TO NORTHWEST FLOW PATTERN ACROSS THE REMAINDER OF THE
CONUS. ONLY SIGNIFICANT ONGOING SENSIBLE WEATHER ARE THUNDERSTORMS
ACROSS THE PLAINS IN ASSOCIATION WITH A WEAK IMPULSE EJECTING OUT OF
THE INTER-MOUNTAIN WEST WITHIN THE MAIN FLOW. WV IMAGERY SHOWS OUR
FORECAST AREA RESIDES UNDER THIS GENERAL WESTERLY FLOW ALOFT AND
THIS IS CONFIRMED BY THE 30/00Z KTBW SOUNDING PROFILE. THE PROFILE
FROM LAST EVENING WAS STILL QUITE DRY THROUGH THE EXTENT OF THE
COLUMN...HOWEVER WE SHOULD SEE THE MID/UPPER LEVELS BEGIN TO MOISTEN
SOMEWHAT OVER THE NEXT 12-18 HOURS AS THE WEAK IMPULSE NOTED ABOVE
APPROACHES FROM THE NORTHWEST.
AT THE SURFACE...SURFACE HIGH PRESSURE IS RIDGING BACK WESTWARD OVER
THE PENINSULA AND EASTERN GULF FROM A POSITION CENTERED NORTH OF THE
BAHAMAS EARLY THIS MORNING. THE RIDGE AXIS AND CLEAR SKIES OVERHEAD
ARE ALLOWING YET ANOTHER COOL OVERNIGHT FOR LATE MARCH...HOWEVER
UNLIKE PREVIOUS MORNING...IT DOES NOT APPEAR AS THOUGH TEMPERATURES
WILL DROP ENOUGH FOR FROST TO BE A REAL CONCERN.
&&
.SHORT TERM (TODAY THROUGH MONDAY)...
TODAY/TONIGHT...
SURFACE HIGH PRESSURE OFF THE SE CONUS COAST WILL RIDGE BACK ACROSS
THE CENTRAL FL PENINSULA. EFFICIENT DIURNAL MIXING AND MODIFIED LOW
LEVEL AIRMASS SHOULD ALLOW AFTERNOON TEMPS TO REACH WELL UP INTO THE
70S NORTH AND INTO THE LOWER 80S SOUTH AWAY FROM THE BEACHES.
VIRTUALLY ALL NWP GUIDANCE IS SHOWING SEA-BREEZE DEVELOPMENT BY
EARLY AFTERNOON...AND WILL FOLLOW LOCAL HI-RES GUIDANCE FOR THE WIND
GRIDS IN TERMS OF TIMING AND STRENGTH FOR THE INLAND PROPAGATION OF
THE INITIAL BOUNDARY. THE SEA-BREEZE WILL HAVE MORE POTENTIAL FOR
SIGNIFICANT INLAND PENETRATION TO THE NORTH OF TAMPA BAY WHERE THE
GRADIENT FLOW ON THE NORTH SIDE OF THE RIDGE AXIS WILL AID IN THE
EASTWARD EXPANSION OF THE CIRCULATION. THE COOLEST SHELF WATERS IN
THE LOWER TO MIDDLE 60S ARE STILL FOUND OFF THE NATURE COAST...AND
THE ONSHORE FLOW OFF THESE WATERS IS LIKELY TO DROP TEMPS BACK DOWN
TOWARD THE UPPER 60S/LOW 70S NEAR THE COAST DURING THE SECOND HALF
OF THE AFTERNOON. WILL SEE SOME COOLING FOR THE SUNCOAST BEACHES
SOUTH OF TAMPA BAY AS WELL...HOWEVER THE WEAKER SEA-BREEZE AND
RELATIVELY WARMER SHELF WATERS SHOULD LIMIT THE COOLING. PLENTY OF
SUNSHINE WILL START THE DAY. DURING THE MIDDLE TO LATER PORTION OF
THE AFTERNOON TIME-HEIGHT PLOTS FROM THE GFS/NAM/ECMWF ALL SHOW AN
EVENTUAL INCREASE IN MID/HIGH LEVEL CLOUDS TO FILTER THE SUN IN
RESPONSE TO THE APPROACH OF A SHORTWAVE IMPULSE. TONIGHT STILL LOOKS
DRY AND SEASONABLY COOL. NO FROST CONCERNS EXPECTED WITH THE COOLEST
LOCATIONS ONLY DROPPING INTO THE UPPER 40S BY SUNRISE. SEVERAL MODEL
RUNS NOW HAVE SHOWN A DECENT SWATH OF MOISTURE COINCIDENT WITH
SYNOPTIC LIFT IN THE MID/UPPER LEVELS ASSOCIATED WITH THIS SHORTWAVE
DURING THE OVERNIGHT PERIOD. APPEARS TO BE ENOUGH FOR SKIES TO
POTENTIALLY GO MOSTLY CLOUDY NORTH OF I-4 FOR A PERIOD.
SUNDAY/SUNDAY NIGHT...
INITIAL SHORTWAVE QUICKLY PULLS EAST OF THE AREA DURING THE MORNING.
THE NEXT SHORTWAVE IN LINE ROTATING AROUND AN AMPLIFYING LONGWAVE
TROUGH WELL TO OUR NORTH WILL BE APPROACHING DURING THE DAY...BUT
SHOULD REMAIN FAR ENOUGH WEST TO HAVE LITTLE IMPACT DURING THE
DAYLIGHT HOURS. LEADING THIS ENERGY...A COLD FRONT WILL PUSH INTO
THE SOUTHEASTERN CONUS DURING THE DAY. THIS FRONT LOOKS TO STALL
NORTH OF I-10 LATER SUNDAY OR SUNDAY NIGHT. THE FORECAST PHILOSOPHY
HAS NOT CHANGED IN THE PAST 24 HOURS...AND ALTHOUGH IT IS NOT OUT OF
THE QUESTION TO SEE A BRIEF SHOWER OR TWO ACROSS LEVY/CITRUS
COUNTIES LATER SUNDAY/SUNDAY NIGHT...THE BETTER LOW LEVEL FOCUS FOR
LIFT REMAINS PROGGED TO STAY NORTH OF OUR ZONES. OF NOTE...THE
CONVECTIVE PARAMETRIZATION SCHEMES FROM A FEW OF THE SREF MEMBERS
ARE STILL KICKING OFF OVER THE PENINSULA (SOUTH OF I-4) DURING
SUNDAY AFTERNOON. THE GFS HAS BACKED OFF ON THIS SCENARIO...AND
SURFACE DEWPOINTS IN THE 50S SEEM TO ARGUE AGAINST ANY INSTABILITY
THAT WOULD CURRENTLY WARRANT SHOWER MENTION IN THE FORECAST.
AVAILABLE CONVECTION ALLOWING GUIDANCE ALSO SHOW LITTLE SHOWER
POTENTIAL AND WILL KEEP POPS AT SILENT 10%. TEMPERATURES WILL BE
SEASONABLE WITH UPPER 70S TO AROUND 80 NORTH OF I-4 AND LOW/MID 80S
FURTHER SOUTH. AFTERNOON SEA-BREEZES WILL AGAIN KEEP THE BEACHES
COOLER.
MONDAY...
SURFACE RIDGE AXIS WILL SETTLE A BIT SOUTH WHILE THE SURFACE COLD
FRONT REMAINS STALLED JUST TO THE NORTH OF I-10. AS THE NEXT
SHORTWAVE IN LINE CROSSES THE AREA...BETTER CHANCES FOR SHOWERS WILL
ARRIVE FOR THE NATURE COAST...ESPECIALLY NORTH OF HERNANDO COUNTY...
IN CLOSER PROXIMITY TO THE FRONTAL FOCUS. ALSO...SLIGHTLY BETTER
CHANCES FOR A FEW SEA-BREEZE FORCED SHOWERS MONDAY AFTERNOON FURTHER
SOUTH ACROSS THE PENINSULA DUE TO BETTER LOW LEVEL MOISTURE AND SOME
AIDED SUPPORT BY THE PASSING SHORTWAVE. BEST CHANCES TO SEE A BRIEF
SHOWER MONDAY AFTERNOON LOOK TO BE WELL INLAND FROM THE GULF...AND
MOST LIKELY OVER BY THE I-95 CORRIDOR WHERE SEA-BREEZE FOCUS WILL BE
MAXIMIZED. FOR NOW WILL SHOW A SLIGHT 20% CHANCE FOR THE AFTERNOON
SHOWERS TO THE EAST OF THE I-75 CORRIDOR. HIGH TEMPS INTO THE 80S
FOR MOST LOCATIONS AWAY FROM THE WATER.
&&
.LONG TERM (MONDAY NIGHT THROUGH NEXT FRIDAY)...
THE PERIOD BEGINS WITH ONE UPPER LOW OVER THE SIERRA NEVADA/GREAT
BASIN REGION AND A SECOND LOW OVER ONTARIO/QUEBEC...RESULTING IN
WESTERLY FLOW ALOFT THE GULF AND FL. AT THE SURFACE A FRONTAL
BOUNDARY WAS STRUNG OUT ALONG THE GULF COAST AND SE U.S. AS HIGH
PRESSURE RIDGED ACROSS FL FROM THE ATLANTIC TO THE GULF. THROUGH THE
REST OF THE WEEK - THE WESTERN LOW BECOMES AN OPEN TROUGH AS IT
TRACKS EASTWARD...REACHING THE EASTERN SEABOARD AND EAST GULF LATE
FRI. THE SURFACE RIDGE RETREATS EAST ALLOWING THE FRONTAL BOUNDARY
TO SAG IN ACROSS THE STATE AND WEAKEN THROUGH WED. MEANWHILE THE
APPROACHING UPPER TROUGH FORMS A INVERTED TROUGH/LOW OVER THE
WESTERN GULF THAT MOVES NORTHEASTWARD CROSSING THE GULF TO THE SE
U.S COASTAL WATERS FRI WITH A COLD FRONT SWEEPING INTO FL.
WITH SOME TIMING AND LOCATION DIFFERENCES BETWEEN THE MODELS HAVE
OPTED TO MAKE FEW CHANGES TO THE CURRENT FORECAST. CLOUDS ALONG WITH
RAIN CHANCES WILL BE INCREASING BUT HAVE KEPT POPS AT 40 PERCENT OR
LESS AND JUST SHOWERS FOR NOW. WINDS WILL BE PICKING UP MID AND LATE
WEEK BUT THAT WILL BE MORE OF A MARINE ISSUE AND HAVE CAPPED WINDS
AROUND 20 KNOTS. TEMPERATURES WILL RUN ABOVE NORMAL ALTHOUGH THEY
WILL COOL SLIGHTLY BY WEEKS END.
&&
.AVIATION...
VFR CONDITIONS FOR THE NEXT 24 HOURS WITH FEW-SCT CUMULUS UNDER SOME
CIRRUS. LIGHT VARIABLE WINDS INCREASE DURING THE MORNING THEN SHIFT
TO ONSHORE IN THE AFTERNOON.
&&
.MARINE...
HIGH PRESSURE WILL CONTINUE TO RIDGE WESTWARD ACROSS THE EASTERN
GULF OF MEXICO THROUGH THE WEEKEND. A WEAK COLD FRONT WILL APPROACH
FROM THE NORTH LATER MONDAY...BUT LIKELY WASH OUT BEFORE REACHING
THE NORTHERN WATERS ON TUESDAY. WINDS AND SEAS ARE FORECAST TO
REMAIN BELOW HEADLINE CRITERIA DURING THE NEXT SEVERAL DAYS.
SEA-BREEZE CIRCULATIONS DEVELOPING THIS AFTERNOON AND AGAIN ON
SUNDAY AFTERNOON WILL TURN WINDS ONSHORE NEAR THE COAST.
&&
.FIRE WEATHER...
ANOTHER DRY DAY ACROSS THE REGION WITH SURFACE HIGH PRESSURE IN
CONTROL. MINIMUM RELATIVE HUMIDITY VALUES AWAY FROM THE COAST WILL
DROP INTO THE UPPER 20S...WITH UP TO 6 HOUR OF CRITICAL RELATIVE
HUMIDITY VALUES POSSIBLE. A DEVELOPING SEA-BREEZE SHOULD HELP TO
BRING INCREASED LOW LEVEL MOISTURE TO LOCATIONS CLOSE TO THE COAST
DURING THE SECOND HALF OF THE AFTERNOON. A RED FLAG WARNING REMAINS
IN EFFECT FOR POLK...HIGHLANDS...AND LEE COUNTIES WHERE RELATIVE
HUMIDITY AND ERC VALUES MEET CRITERIA. A SLOW INCREASE IN LOW LEVEL
MOISTURE WILL LIKELY PREVENT CRITICAL DURATIONS OF LOW RELATIVE
HUMIDITY ON SUNDAY ALTHOUGH A FEW HOURS OF SUB 35 PERCENT READINGS
WILL BE POSSIBLE EAST OF THE I-75 CORRIDOR. A FURTHER INCREASE OF
LOW LEVEL MOISTURE SHOULD END FIRE WEATHER CONCERNS BY MONDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 75 58 79 63 / 0 0 0 10
FMY 80 60 85 63 / 0 0 10 10
GIF 79 55 82 61 / 0 0 10 10
SRQ 74 58 78 62 / 0 0 0 10
BKV 77 49 81 57 / 0 10 0 10
SPG 75 62 79 65 / 0 0 0 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...RED FLAG WARNING FROM NOON TODAY TO 8 PM EDT THIS EVENING
FOR HIGHLANDS-LEE-POLK.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM/AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
920 PM EDT SUN MAR 31 2013
.UPDATE...
WEAK CONVERGENCE BOUNDARY SITUATED ACROSS CENTRAL GA THIS EVENING.
WV ANALYSIS SHOWS A MID LEVEL SHORTWAVE AXIS MOVING THROUGH CENTRAL
AL. THIS FEATURE...ALONG WITH SOME MARGINAL INSTABILITY AT THE
SURFACE...HAS HELPED FIRE AND SUSTAIN CONVECTION ACROSS THE SOUTHERN
CWFA THIS EVENING. FOR THE PAST HOUR...CONVECTION HAS DECREASED IN
INTENSITY AND A LITTLE IN COVERAGE.
MADE A FEW UPDATES TO THE ONGOING FORECAST. HAVE REDUCED POPS ACROSS
NORTHERN SECTIONS FROM CATEGORICAL TO LIKELY/HIGH END CHANCE. THERE
IS VERY LITTLE FORCING ALONG THE CONVERGENCE ZONE ITSELF. MESOSCALE
OUTFLOW BOUNDARY ACROSS THE CENTRAL CWFA CONTINUES MOVE NORTH...AND
HAS PROVIDED SOME LIFT FOR SCT SHOWERS.
ALSO...BUMPED MIN TEMPS UP A FEW DEGREES.
&&
.PREV DISCUSSION... /ISSUED 744 PM EDT SUN MAR 31 2013/
PREV DISCUSSION... /ISSUED 329 PM EDT SUN MAR 31 2013/
SHORT TERM /TONIGHT THROUGH TUESDAY/...
SCATTERED SHOWERS WILL BECOME MORE WIDESPREAD THIS EVENING AS THE
COLD FRONT MOVES INTO THE TENNESSEE VALLEY. THE ATMOSPHERE AHEAD OF
THE FRONT IS TROPICAL IN NATURE AND THE SMALL SHOWERS ARE PUTTING
OUT SOME HEAVY RAINFALL. THERE WILL ALSO BE ISOLATED TO SCATTERED
THUNDER MIXED IN WITH THE SHOWERS. THE PRECIP WILL END FROM THE
NORTHWEST LATE TONIGHT WITH MOST AREAS BECOMING PARTLY SUNNY BY LATE
MORNING ON MONDAY. GUIDANCE TEMPS LOOK REASONABLE AND HAVE MADE ONLY
MINOR CHANGES TO TEMPS FOR TONIGHT AND MONDAY.
/17
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE LATEST 12Z ECMWF AND GFS MODEL RUNS ARE NOW IN MUCH BETTER
AGREEMENT WITH RESPECT TO OVERALL POSITION AND TIMING OF OUR LOW
PRESSURE SYSTEM TOWARD END WEEK. BOTH MODELS NOW TRACK THE SURFACE
LOW OVER MAINLY SOUTH GA THURSDAY NIGHT... WITH MOST OF THE FORECAST
AREA REMAINING IN A COOLER NORTHEAST WEDGE FLOW AT THE SURFACE...
RESULTING IN MORE OF A STABLE OVERRUNNING RAIN EVENT FOR THURSDAY
AND THURSDAY NIGHT. HOWEVER... APPEARS THAT PARTS OF CENTRAL GA COULD
GET IN THE WARM SECTOR THURSDAY EVENING AND OVERNIGHT... WHICH WOULD
SUPPORT MORE SURFACE BASED CONVECTION IN THAT AREA. WITH MUCH UNCERTAINTY
ON THE PROGRESSION OF THE WARM FRONT NORTHWARD INTO CENTRAL GEORGIA...
ALL INTEREST ARE ADVISED TO MONITOR LATER FORECAST CLOSELY FOR POTENTIAL
SEVERE WEATHER RISK DEVELOPING ALONG AND SOUTH OF THE WARM FRONT ON
THURSDAY AND THURSDAY NIGHT. AT THIS TIME... IT APPEARS THIS EVENT
COULD BE MORE OF A HEAVY RAIN EVENT... WHERE 1 TO 3 INCHES OF RAIN
LOOKS POSSIBLE OVER THE FORECAST AREA FROM EARLY THURSDAY THROUGH EARLY
FRIDAY... WITH THE GREATER AMOUNTS EXPECTED OVER CENTRAL GA WHERE THE
HEAVIER...MORE UNSTABLE CONVECTION APPEARS MORE LIKELY TO OCCUR AT
THIS TIME. EXPECT TO CLEAR OUT ON FRIDAY WITH HIGH PRESSURE AND
DRIER CONDITIONS ON TAP FOR THE WEEKEND. /39
PREVIOUS LONG TERM ... /MONDAY NIGHT THROUGH SATURDAY/
/ISSUED AT 415 AM EDT SUN MAR 31 2013/
MAIN RAIN EVENT WILL ENCOMPASS THE SECOND HALF OF THE WEEK.
GFS/EUROPEAN SIMILAR WITH BRINGING RAIN TO THE AREA POSSIBLY AS
EARLY AS TUESDAY NIGHT/WEDNESDAY BUT MORE SO WEDNESDAY NIGHT INTO
FRIDAY. A WARM FRONT DEVELOPS ALONG THE GULF COAST WITH
OVERRUNNING MOIST FLOW SETTING UP. THE MAIN DIFFERENCE BETWEEN THE
GFS AND EUROPEAN IS THE EUROPEAN BRINGS SURFACE LOW PRESSURE
ACROSS CENTRAL TO S GA THURSDAY NIGHT AND FRIDAY WHILE THE GFS
TAKES THE SURFACE LOW ACROSS N FL. GFS BRINGS ONLY MINIMAL MUCAPE
INTO CENTRAL GA THURSDAY/THURSDAY NIGHT. IF THE EUROPEAN SURFACE
SOLUTION COMES TO PASS THE CHANCES FOR THUNDERSTORMS WOULD BE
GREATER WITH THE WARM FRONT POSSIBLY GETTING INTO CENTRAL GA WITH
A LOW END THREAT FOR SEVERE WEATHER. EITHER WAY A GOOD RAIN EVENT
WITH 1 TO 2 INCHES ACROSS CENTRAL GA. THE UPPER TROUGH MOVES TO
THE AREA FRIDAY WITH THE GFS A LITTLE FASTER WITH THE TROUGH AND
MOISTURE EXITING THAN THE EUROPEAN. A DAMPENING SHORT WAVE RIDGE
AND SURFACE HIGH PRESSURE MOVE TO THE AREA SATURDAY WITH DRY
CONDITIONS EXPECTED AND THIS LOOKS TO CONTINUE FOR SUNDAY.
BDL
AVIATION...
00Z UPDATE...
WEAK CONVERGENCE BOUNDARY REMAINS SITUATED ACROSS SOUTH CENTRAL GA
THIS EVENING. 500MB ANALYSIS SHOWS A MID LEVEL SHORTWAVE TROUGH AXIS
ACROSS WESTERN AL MOVING EAST. THIS FEATURE HAS HELPED FIRE AND
SUSTAIN CONVECTION. LATEST HRRR RUN DOES SHOW SHOWERS MOVING IN FROM
THE NW OVERNIGHT...WITH THE MID LEVEL TROUGH AXIS. REDUCED
CIGS/VSBYS IN SHRA THROUGH 8Z. PATCHY FOG WILL LIKELY DEVELOP WITH
VSBYS IN THE 4-6SM RANGE. IFR CIGS WITH RAIN SHOULD HANG AROUND
THROUGH SUNRISE. A WIND SHIFT TO THE NW SHOULD OCCUR AROUND 12Z MON.
//ATL CONFIDENCE...00Z UPDATE...
MEDIUM CONFIDENCE ALL ELEMENTS.
NLISTEMAA
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 54 75 46 65 / 80 10 10 10
ATLANTA 54 71 50 62 / 80 10 10 10
BLAIRSVILLE 47 67 39 60 / 90 10 20 10
CARTERSVILLE 51 72 43 60 / 80 10 10 10
COLUMBUS 59 77 52 75 / 80 30 5 10
GAINESVILLE 51 72 47 60 / 80 10 10 10
MACON 58 77 48 73 / 80 30 5 10
ROME 50 72 43 60 / 80 10 20 10
PEACHTREE CITY 54 73 45 66 / 80 10 5 10
VIDALIA 60 76 53 77 / 70 60 10 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...LISTEMAA
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
744 PM EDT SUN MAR 31 2013
.PREV DISCUSSION... /ISSUED 329 PM EDT SUN MAR 31 2013/
SHORT TERM /TONIGHT THROUGH TUESDAY/...
SCATTERED SHOWERS WILL BECOME MORE WIDESPREAD THIS EVENING AS THE
COLD FRONT MOVES INTO THE TENNESSEE VALLEY. THE ATMOSPHERE AHEAD OF
THE FRONT IS TROPICAL IN NATURE AND THE SMALL SHOWERS ARE PUTTING
OUT SOME HEAVY RAINFALL. THERE WILL ALSO BE ISOLATED TO SCATTERED
THUNDER MIXED IN WITH THE SHOWERS. THE PRECIP WILL END FROM THE
NORTHWEST LATE TONIGHT WITH MOST AREAS BECOMING PARTLY SUNNY BY LATE
MORNING ON MONDAY. GUIDANCE TEMPS LOOK REASONABLE AND HAVE MADE ONLY
MINOR CHANGES TO TEMPS FOR TONIGHT AND MONDAY.
/17
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE LATEST 12Z ECMWF AND GFS MODEL RUNS ARE NOW IN MUCH BETTER
AGREEMENT WITH RESPECT TO OVERALL POSITION AND TIMING OF OUR LOW
PRESSURE SYSTEM TOWARD END WEEK. BOTH MODELS NOW TRACK THE SURFACE
LOW OVER MAINLY SOUTH GA THURSDAY NIGHT... WITH MOST OF THE FORECAST
AREA REMAINING IN A COOLER NORTHEAST WEDGE FLOW AT THE SURFACE...
RESULTING IN MORE OF A STABLE OVERRUNNING RAIN EVENT FOR THURSDAY
AND THURSDAY NIGHT. HOWEVER... APPEARS THAT PARTS OF CENTRAL GA COULD
GET IN THE WARM SECTOR THURSDAY EVENING AND OVERNIGHT... WHICH WOULD
SUPPORT MORE SURFACE BASED CONVECTION IN THAT AREA. WITH MUCH UNCERTAINTY
ON THE PROGRESSION OF THE WARM FRONT NORTHWARD INTO CENTRAL GEORGIA...
ALL INTEREST ARE ADVISED TO MONITOR LATER FORECAST CLOSELY FOR POTENTIAL
SEVERE WEATHER RISK DEVELOPING ALONG AND SOUTH OF THE WARM FRONT ON
THURSDAY AND THURSDAY NIGHT. AT THIS TIME... IT APPEARS THIS EVENT
COULD BE MORE OF A HEAVY RAIN EVENT... WHERE 1 TO 3 INCHES OF RAIN
LOOKS POSSIBLE OVER THE FORECAST AREA FROM EARLY THURSDAY THROUGH EARLY
FRIDAY... WITH THE GREATER AMOUNTS EXPECTED OVER CENTRAL GA WHERE THE
HEAVIER...MORE UNSTABLE CONVECTION APPEARS MORE LIKELY TO OCCUR AT
THIS TIME. EXPECT TO CLEAR OUT ON FRIDAY WITH HIGH PRESSURE AND
DRIER CONDITIONS ON TAP FOR THE WEEKEND. /39
PREVIOUS LONG TERM ... /MONDAY NIGHT THROUGH SATURDAY/
/ISSUED AT 415 AM EDT SUN MAR 31 2013/
MAIN RAIN EVENT WILL ENCOMPASS THE SECOND HALF OF THE WEEK.
GFS/EUROPEAN SIMILAR WITH BRINGING RAIN TO THE AREA POSSIBLY AS
EARLY AS TUESDAY NIGHT/WEDNESDAY BUT MORE SO WEDNESDAY NIGHT INTO
FRIDAY. A WARM FRONT DEVELOPS ALONG THE GULF COAST WITH
OVERRUNNING MOIST FLOW SETTING UP. THE MAIN DIFFERENCE BETWEEN THE
GFS AND EUROPEAN IS THE EUROPEAN BRINGS SURFACE LOW PRESSURE
ACROSS CENTRAL TO S GA THURSDAY NIGHT AND FRIDAY WHILE THE GFS
TAKES THE SURFACE LOW ACROSS N FL. GFS BRINGS ONLY MINIMAL MUCAPE
INTO CENTRAL GA THURSDAY/THURSDAY NIGHT. IF THE EUROPEAN SURFACE
SOLUTION COMES TO PASS THE CHANCES FOR THUNDERSTORMS WOULD BE
GREATER WITH THE WARM FRONT POSSIBLY GETTING INTO CENTRAL GA WITH
A LOW END THREAT FOR SEVERE WEATHER. EITHER WAY A GOOD RAIN EVENT
WITH 1 TO 2 INCHES ACROSS CENTRAL GA. THE UPPER TROUGH MOVES TO
THE AREA FRIDAY WITH THE GFS A LITTLE FASTER WITH THE TROUGH AND
MOISTURE EXITING THAN THE EUROPEAN. A DAMPENING SHORT WAVE RIDGE
AND SURFACE HIGH PRESSURE MOVE TO THE AREA SATURDAY WITH DRY
CONDITIONS EXPECTED AND THIS LOOKS TO CONTINUE FOR SUNDAY.
BDL
&&
.AVIATION...
00Z UPDATE...
WEAK CONVERGENCE BOUNDARY REMAINS SITUATED ACROSS SOUTH CENTRAL GA
THIS EVENING. 500MB ANALYSIS SHOWS A MID LEVEL SHORTWAVE TROUGH AXIS
ACROSS WESTERN AL MOVING EAST. THIS FEATURE HAS HELPED FIRE AND
SUSTAIN CONVECTION. LATEST HRRR RUN DOES SHOW SHOWERS MOVING IN FROM
THE NW OVERNIGHT...WITH THE MID LEVEL TROUGH AXIS. REDUCED
CIGS/VSBYS IN SHRA THROUGH 8Z. PATCHY FOG WILL LIKELY DEVELOP WITH
VSBYS IN THE 4-6SM RANGE. IFR CIGS WITH RAIN SHOULD HANG AROUND
THROUGH SUNRISE. A WIND SHIFT TO THE NW SHOULD OCCUR AROUND 12Z MON.
//ATL CONFIDENCE...00Z UPDATE...
MEDIUM CONFIDENCE ALL ELEMENTS.
NLISTEMAA
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 54 75 46 65 / 80 10 10 10
ATLANTA 54 71 50 62 / 80 10 10 10
BLAIRSVILLE 47 67 39 60 / 90 10 20 10
CARTERSVILLE 51 72 43 60 / 80 10 10 10
COLUMBUS 59 77 52 75 / 80 30 5 10
GAINESVILLE 51 72 47 60 / 80 10 10 10
MACON 58 77 48 73 / 80 30 5 10
ROME 50 72 43 60 / 80 10 20 10
PEACHTREE CITY 54 73 45 66 / 80 10 5 10
VIDALIA 60 76 53 77 / 70 60 10 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
404 PM CDT SAT MAR 30 2013
...UPDATED SHORT TERM AND LONG TERM SECTIONS...
.SYNOPSIS...
ISSUED AT 215 PM CDT SAT MAR 30 2013
THE LONGWAVE PATTERN WAS CHARACTERIZED BY NORTHWEST FLOW FROM
WESTERN CANADA INTO THE CENTRAL CONUS. SEVERAL SHORTWAVE TROUGHS
EMBEDDED IN THE NORTHWEST FLOW PATTERN COULD BE IDENTIFIED ON WATER
VAPOR LOOP AND RAP ANALYSIS. THE DISTURBANCE WHICH LED TO LAST
NIGHT`S SEVERE WEATHER EVENT WAS LOCATED OVER MISSOURI AND ARKANSAS
EARLY THIS AFTERNOON. FARTHER UPSTREAM...ANOTHER SHORTWAVE TROUGH
WAS EVIDENT FROM WYOMING TO SOUTH DAKOTA. MEANWHILE...A FAIRLY LARGE
UPPER LOW WAS CENTERED OFF THE COAST OF CALIFORNIA DISCONNECTED FROM
THE POLAR JET STREAM FLOW. A SUBTROPICAL JET CONTAINED A FAIR AMOUNT
OF HIGH LEVEL CIRRUS IN THE LOW LATITUDES SOUTH OF THE
AFOREMENTIONED UPPER LOW INTO WESTERN MEXICO. AT THE SURFACE...A
WEAK TROUGH AXIS EXTENDED FROM NORTHEAST KANSAS INTO WESTERN
OKLAHOMA. THE NORTH TO NORTHWEST WINDS BEHIND THE TROUGH AXIS HAD
LOWER MOISTURE CONTENT WITH DEWPOINTS IN THE UPPER 30S TO LOWER 40S.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 403 PM CDT SAT MAR 30 2013
THE SHORTWAVE TROUGH MOVING SOUTHEAST ACROSS WESTERN NEBRASKA WILL
AID IN THE DEVELOPMENT OF SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS LATE THIS AFTERNOON ACROSS SOUTHWEST NEBRASKA AND
NORTHEAST COLORADO. THE AIRMASS IN THIS REGION IS DRY WITH DEWPOINT
TEMPERATURES ONLY IN THE LOWER TO MID 30S. STEEP LAPSE RATES WERE
FOUND AHEAD OF THIS SHORTWAVE TROUGH AS SURFACE TEMPERATURES WARM
INTO THE LOWER TO MID 60S...AND MID LEVEL TEMPERATURES WERE COLD
(-20 TO -22C AT 500MB, 0 TO -4C AT 700MB). THIS THERMODYNAMIC
SETTING RESULTED IN A LITTLE BIT OF CONVECTIVE INSTABILITY WITH
SBCAPE AROUND A COUPLE HUNDRED J/KG. THERE WILL BE LOOSELY ORGANIZED
SHOWERS AND EMBEDDED THUNDER MOVING SOUTHEAST FROM THE CO/NE/KS
TRI-BORDER REGION TO WESTERN/CENTRAL KANSAS LATE TONIGHT. MID LEVEL
COLD ADVECTION AND DEEP TROPOSPHERIC ASCENT AHEAD OF THE WAVE WILL
AID IN SUSTAINING SHOWER AND THUNDER ACTIVITY THROUGH THE NIGHT.
AREAS CLOSER TO CENTRAL KANSAS (I.E. ELLIS COUNTY) WILL STAND A
BETTER CHANCE AT MORE ORGANIZED CONVECTION AS REMNANT LOW LEVEL
MOISTURE WAS HANGING AROUND AFTER THE TROUGH PASSAGE FROM EARLIER
TODAY. POPS WERE RAISED TO 40 TO 50 PERCENT...ESPECIALLY IN THE
NORTHEASTERN DDC FORECAST AREA (CLOSER TO CENTRAL KANSAS).
SUBSIDENCE IN THE WAKE OF THE SHORTWAVE TROUGH WILL MOVE INTO WEST
CENTRAL KANSAS DURING THE 09-12Z TIME FRAME...AND THE SHOWER
ACTIVITY WILL MOVE INTO SOUTH CENTRAL KANSAS AND NORTHERN OKLAHOMA.
AS FAR AS TEMPERATURES GO...COLD ADVECTION WILL BE RATHER WEAK AT
THE SURFACE WITH SOME DOWNSLOPE MODIFICATION...SO LOWS TONIGHT AFTER
THE SHOWERS MOVE THROUGH WILL ONLY BOTTOM OUT IN THE UPPER 30S TO
LOWER 40S. ON SUNDAY...SUBSIDENCE WILL PREVAIL WITH WEAK SURFACE
HIGH YIELDING LIGHT WINDS THROUGH THE DAY. HIGHS WERE LOWERED JUST
A COUPLE DEGREES INTO THE UPPER 60S GIVEN THE SLIGHTLY COOLER LOWER
TROPOSPHERE BEHIND THE WAVE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 403 PM CDT SAT MAR 30 2013
A COLD CANADIAN HIGH PRESSURE WILL AGAIN INFLUENCE THE WEATHER FOR
AT LEAST THE MONDAY THROUGH WEDNESDAY TIMEFRAME. BOTH THE GFS AND
ECMWF ALLOW A SURFACE BACKDOOR COLD FRONT TO SLIDE INTO WESTERN
KANSAS SUNDAY NIGHT INTO EARLY MONDAY, BRINGING EASTERLY UPSLOPE
WINDS THAT REMAIN ESTABLISHED THROUGH ABOUT WEDNESDAY MORNING.
ADDITIONALLY, THE MODELS HAVE BEEN VERY CONSISTENT NOW FOR SEVERAL
DAYS IN DEVELOPING A PROGRESSIVE TROUGH OVER THE WESTERN UNITED
STATES WHICH DIGS INTO THE SOUTHERN ROCKIES BY TUESDAY AND TUESDAY
NIGHT. THE RESULT WILL BE AN INCREASING CHANCE OF PRECIPITATION
(EITHER RAIN/SNOW OR BOTH) FROM THE LATE MONDAY TIMEFRAME THROUGH
TUESDAY AND WEDNESDAY MORNING. WITH THE COOL AND EASTERLY UPSLOPE
EXPECTED BY MONDAY, TEMPERATURES WILL DROP 20 TO 30 DEGREES FROM
SUNDAY AFTERNOON`S LOW 70`S. STRATUS WILL LIKELY IMPEDE INSOLATION
SIGNIFICANTLY DURING THE TIMEFRAME BASED ON MODEL 925-850 MB
RELATIVE HUMIDITY FIELDS. THROUGH THE DAY THE LAYER BECOME THICKER
WITH TIME, WHICH MIGHT SUGGEST SOME LIGHT FOG OR EVEN DRIZZLE
POTENTIAL THROUGH THE OVERNIGHT SUNDAY WITH TEMPERATURES REMAINING
ABOVE FREEZING. SNOW PRECIPITATION TYPE REALLY WON`T BE DEPENDENT ON
THE ARRIVAL OF COLD ENOUGH AIR ALOFT, BUT RATHER THE MOISTENING UP OF A
DEEP ENOUGH SATURATED LAYER THROUGH THE QG-FRONTOGENESIS/ISENTROPIC
LIFTING PROCESS ON TUESDAY.
THE LATEST ECMWF MODEL RUN DEPICT THE HEAVIER SNOWFALL TO OCCUR
FARTHER SOUTHWEST OVER SOUTHEAST COLORADO AND THE PANHANDLES, THAN
THE GFS MODEL RUNS WHICH FORECASTS HEAVY SNOW ACROSS SOUTHWEST
KANSAS. AT A MINIMUM THE MODEL TRENDS LEND CONFIDENCE TO HIGHER
CHANCES FOR PRECIPITATION DURING THIS TIMEFRAME, AND INFLUENCING
COOLER TEMPERATURES FOR WEDNESDAY. THE REMAINDER OF THE WEEK SHOULD
BRING A WARMING TREND BACK TOWARD CLIMATOLOGY AS UPPER LEVEL RIDGING
TO FLAT ZONAL UPPER LEVEL FLOW AND SOUTHERLY SURFACE WINDS BECOME
RE-ESTABLISHED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 215 PM CDT SAT MAR 30 2013
SHOWERS AND ISOLATED THUNDERSTORMS WILL MOVE SOUTHEAST ACROSS
WESTERN KANSAS DURING THE LATE EVENING HOURS. A COLD FRONT WILL MOVE
SOUTH TIED TO A SHORTWAVE TROUGH MOVING SOUTHEAST OUT OF NEBRASKA.
BEHIND THE FRONT...CEILINGS WILL DEVELOP IN THE MVFR RANGE AND WILL
FORECAST 1500 TO 2500 CEILING IN THE 09-15Z TIME FRAME. THERE WILL
BE A 2 OR 3 HOUR PERIOD OF FAIRLY STRONG NORTH TO NORTHWEST WINDS
IMMEDIATELY BEHIND THE FRONT OF 20 TO 25 KNOTS WITH SOME GUSTS ABOVE
30 KNOTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 40 68 35 45 / 40 10 40 40
GCK 38 68 35 44 / 40 10 30 40
EHA 41 68 40 44 / 30 10 30 40
LBL 41 68 42 45 / 30 10 30 40
HYS 38 67 34 44 / 50 10 40 40
P28 47 69 40 46 / 40 10 50 50
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...RUSSELL
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
216 PM CDT SAT MAR 30 2013
...UPDATED AVIATION AND SYNOPSIS SECTIONS...
.SYNOPSIS...
ISSUED AT 215 PM CDT SAT MAR 30 2013
THE LONGWAVE PATTERN WAS CHARACTERIZED BY NORTHWEST FLOW FROM
WESTERN CANADA INTO THE CENTRAL CONUS. SEVERAL SHORTWAVE TROUGHS
EMBEDDED IN THE NORTHWEST FLOW PATTERN COULD BE IDENTIFIED ON WATER
VAPOR LOOP AND RAP ANALYSIS. THE DISTURBANCE WHICH LED TO LAST
NIGHT`S SEVERE WEATHER EVENT WAS LOCATED OVER MISSOURI AND ARKANSAS
EARLY THIS AFTERNOON. FARTHER UPSTREAM...ANOTHER SHORTWAVE TROUGH
WAS EVIDENT FROM WYOMING TO SOUTH DAKOTA. MEANWHILE...A FAIRLY LARGE
UPPER LOW WAS CENTERED OFF THE COAST OF CALIFORNIA DISCONNECTED FROM
THE POLAR JET STREAM FLOW. A SUBTROPICAL JET CONTAINED A FAIR AMOUNT
OF HIGH LEVEL CIRRUS IN THE LOW LATITUDES SOUTH OF THE
AFOREMENTIONED UPPER LOW INTO WESTERN MEXICO. AT THE SURFACE...A
WEAK TROUGH AXIS EXTENDED FROM NORTHEAST KANSAS INTO WESTERN
OKLAHOMA. THE NORTH TO NORTHWEST WINDS BEHIND THE TROUGH AXIS HAD
LOWER MOISTURE CONTENT WITH DEWPOINTS IN THE UPPER 30S TO LOWER 40S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 234 AM CDT SAT MAR 30 2013
TODAY:
NORTHWESTERLY FLOW ALOFT AND AN EMBEDDED SHORTWAVE TROF WILL MOVE ACROSS
THE NORTHERN PRAIRIES AND ACROSS THE CENTRAL PLAINS TODAY. THIS UL FEATURE
WILL USHER IN THE PASSAGE FOR A COLD FRONT WITH MUCH DRIER AIR ADVECTING
IN ACROSS THE REGION. NNW WINDS WILL STILL BE DOWNSLOPE AND A WARM 850
HPA PLUME WILL ADVECT ACROSS THE REGION, SO TEMPERATURES ARE EXPECTED
TO BE WARM. FORECASTING HIGHS IN THE MID TO UPPER 70S DEG F, WHICH IS
IN LINE WITH MOS GUIDANCE.
TONIGHT:
AN AREA OF ENHANCED 800-600 HPA FRONTOGENESIS WILL MOVE ACROSS THE REGION
AND COULD RESULT IN A FEW SHOWERS TONIGHT. EVEN THOUGH 500 HPA TEMPERATURES
ARE FAIRLY COLD /-20 DEG C/ NOT EXPECTING MUCH INSTABILITY AS THE DRY
AIR ADVECTS IN AND THE HIGHER THETA-E AXIS MOVES EAST OF THE REGION.
OVERNIGHT LOWS INTO SUNDAY WILL BE COOLER WITH THE DRIER AIRMASS - 30S
AND 40S DEG F.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 347 AM CDT SAT MAR 30 2013
A STRONG COLD FRONT IS STILL ADVERTISED TO PUSH SOUTH ACROSS THE
CENTRAL HIGH PLAINS LATE SUNDAY NIGHT INTO EARLY MONDAY. THE MEDIUM
RANGE MODELS ARE FOR THE MOST PART CONTINUING TO TREND TOWARD A
LESSENING IMPACT OF COLD AIR BEHIND THE FRONT. THE CANADIAN AND
ECMWF KEEP 850 MB TEMPERATURES ABOVE 0C ON MONDAY WHILE THE GFS IS
THE COLDEST WITH BELOW 0C TEMPERATURES SPREADING SOUTH THROUGH
NEARLY ALL OF SOUTHWEST KANSAS. HOWEVER, EVEN THIS MODEL IS NOT AS
COLD AS IT WAS A FEW DAYS AGO. HAVE BACKED OFF A BIT ON THE MENTION
OF SNOW FOR MONDAY...KEEPING IT CONFINED TO THE AREA ALONG AND NORTH
OF HIGHWAY 96 DURING THE DAY. WILL KEEP SOME SLIGHT CHANCES FOR RAIN
OR SNOW GOING MONDAY NIGHT INTO TUESDAY OVER FAR SOUTHWEST KANSAS AS
THE REMAINS OF THE WEST COAST SYSTEM MOVE OUT INTO THE CENTRAL AND
SOUTHERN PLAINS. THROUGH THE REMAINDER OF THE EXTENDED PERIOD WE
SHOULD SEE WARMER TEMPERATURES RETURN AS UPPER LEVEL RIDGING BUILDS
BACK INTO THE CENTRAL PART OF THE COUNTRY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 215 PM CDT SAT MAR 30 2013
SHOWERS AND ISOLATED THUNDERSTORMS WILL MOVE SOUTHEAST ACROSS
WESTERN KANSAS DURING THE LATE EVENING HOURS. A COLD FRONT WILL MOVE
SOUTH TIED TO A SHORTWAVE TROUGH MOVING SOUTHEAST OUT OF NEBRASKA.
BEHIND THE FRONT...CEILINGS WILL DEVELOP IN THE MVFR RANGE AND WILL
FORECAST 1500 TO 2500 CEILING IN THE 09-15Z TIME FRAME. THERE WILL
BE A 2 OR 3 HOUR PERIOD OF FAIRLY STRONG NORTH TO NORTHWEST WINDS
IMMEDIATELY BEHIND THE FRONT OF 20 TO 25 KNOTS WITH SOME GUSTS ABOVE
30 KNOTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 39 71 35 45 / 40 10 40 40
GCK 38 71 35 44 / 40 10 30 40
EHA 41 71 40 44 / 30 10 30 40
LBL 41 71 42 45 / 30 10 30 40
HYS 38 70 34 44 / 50 10 40 40
P28 47 72 40 46 / 40 10 50 50
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...SUGDEN
LONG TERM...GERARD
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1006 AM CDT SAT MAR 30 2013
.UPDATE...
ISSUED AT 955 AM CDT SAT MAR 30 2013
UPDATED FORECAST TO REMOVE POPS THIS MORNING ACROSS MUCH OF THE
AREA. SCATTERED SHOWERS WILL CONTINUE ACROSS BROWN...NORTHERN
JACKSON AND NORTHERN JEFFERSON THROUGH NOON.
SHOWERS AND THUNDERSTORMS WILL REDEVELOP AHEAD OF A COLD FRONT
ACROSS NORTHEAST AND EAST CENTRAL KS THIS AFTERNOON. IF WE GET
INSOLATION LATE THIS MORNING AND DURING THE AFTERNOON HOURS...THE
ATMOSPHERE MAY DESTABILIZE ENOUGH DURING THE AFTERNOON HOURS FOR SOME
OF THE THUNDERSTORMS TO BECOME STRONG TO POSSIBLY SEVER...WITH THE
PRIMARY HAZARD BEING QUARTER SIZE HAIL AND STRONG WIND GUSTS.
GARGAN
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
WATER VAPOR IMAGERY SHOWING ONE SHORTWAVE TROUGH OVER NE MOVING
SOUTHEAST WITH CONVECTION OUT AHEAD OF IT WITHIN WAA REGIME ACROSS
SOUTHERN NE INTO CENTRAL KS. THIS AREA OF CONVECTION WILL CONTINUE
TO MOVE EAST AND SOUTHEAST ACROSS THE CWA THROUGH SUNRISE BEFORE
DIMINISHING. A COLD FRONT OVER CENTRAL NE WILL MOVE SOUTHEAST ACROSS
THE CWA THROUGH THE MIDDAY/AFTERNOON HOURS. IF SUFFICIENT
HEATING/DESTABILIZATION IN THE WAKE OF THIS MORNINGS ACTIVITY
OCCURS...MUCAPES OF 1500-2000 J/KG ARE POSSIBLE ACROSS THE SOUTHEAST
CWA...PRIMARILY ALONG AND SOUTHEAST OF THE I 35 CORRIDOR AT THE TIME
OF THE FROPA. IF ANY ISOLATED TO SCATTERED CONVECTION IS ABLE TO
REDEVELOP ALONG/AHEAD OF THE FRONT WITHIN THIS ENVIRONMENT...THEY
MAY BECOME CAPABLE OF PRODUCING SOME HAIL TO QUARTER SIZE AND STRONG
GUSTY WINDS. THIS ACTIVITY WOULD LIKELY EXIT THE FAR SOUTHEAST CWA
BY EARLY EVENING...ALTHOUGH MORE POST FRONTAL SHOWERS COULD STILL
REDEVELOP FURTHER TOWARDS THE NORTHWEST IN ADVANCE OF THE SHORTWAVE
TROUGH CURRENTLY MOVING INTO WY. ANY SHOWERS ASSOCIATED WITH THIS
SHOULD DISSIPATE BY MIDNIGHT...LEAVING THE REMAINDER OF NIGHT DRY
AND COOLER.
SUNDAY STILL LOOKING DRY AND MILD WITH HIGHS GENERALLY 65 TO 70 IN
ADVANCE OF THE NEXT MUCH STRONGER COLD FRONT TO THE NORTH. THIS
FRONT WILL PASS THROUGH THE CWA NORTH TO SOUTH THROUGH THE EVENING
WITH A CHANCE FOR RAIN...THEN A CHANCE FOR RAIN OR SNOW OVERNIGHT
INTO MONDAY AS THE COLDER AIR PLUNGES SOUTHWARD. ANY SNOWFALL APPEAR
SHOULD PRIMARILY BE UNDER HALF AN INCH AT THIS TIME. THE WINTRY MIX
POTENTIAL WILL SHIFT TO THE SOUTHERN CWA THROUGH AFTERNOON THEN END
BY EVENING...BUT AGAIN AMOUNTS SHOULD BE VERY LIGHT. 63
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 955 AM CDT SAT MAR 30 2013*
ISSUED AT 955 AM CDT SAT MAR 30 2013
MODELS STILL KEEPING THE NEXT TROUGH IN THE ROCKIES TO THE SOUTH OF
THE AREA THROUGH MID WEEK WITH DRY CONDITIONS AND A GRADUAL
MODERATION IN TEMPS AS THE AREA GRADUALLY TRANSITIONS FROM NORTHWEST
FLOW ALOFT TO A MORE ZONAL FLOW. HIGHS SHOULD RISE FROM NEAR 40 ON
MONDAY TO THE 50S BY WEDNESDAY...THEN THE 60S AGAIN BY FRIDAY. LOWS
IN THE 20S EARLY IN THE WEEK SHOULD RISE TO NEAR 40 BY FRIDAY. 63
&&
.AVIATION...
LOW CIGS HAVE HAD A HARD TIME MOVING INTO THE TERMINALS AND THINK
THE MODELS CONTINUE TO BE TO COOL IN THE BOUNDARY LAYER AND
OVERDOING THE RH. OUTSIDE OF SOME LIGHT SHOWERS...THINK CONDITIONS
WILL TEND TO BE VFR. ONLY EXCEPTION WOULD BE IF WE CLEAR OUT. THEN
THERE COULD BE SOME RADIATIONAL FOG...BUT THINK THE CLOUDS WILL HANG
IN UNTIL AFTER SUNRISE. FROPA SHOULD OCCUR IN THE EARLY TO MID
AFTERNOON. SOME OF THE HIGH RES SOLUTIONS SHOW SOME WEAK POP UP
SHOWERS POSSIBLE UNTIL THE FRONT MOVES THROUGH. THE HRRR SEEMS TO BE
DOING THE BEST WITH THIS MORNINGS PRECIP AND TAKES MOST OF THE
ACTIVITY EAST OF TOP AND FOE BY 15Z. SO WILL KEEP A DRY FORECAST DUE
TO LOW CONFIDENCE IN LOCATION OF ANY ISOLATED SHOWER ACTIVITY THIS
AFTERNOON.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GARGAN
SHORT TERM...63
LONG TERM...63
AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
617 AM CDT SAT MAR 30 2013
.DISCUSSION...
SEE PREV DISCUSSION.
&&
.AVIATION...
LOW CIGS HAVE HAD A HARD TIME MOVING INTO THE TERMINALS AND THINK
THE MODELS CONTINUE TO BE TO COOL IN THE BOUNDARY LAYER AND
OVERDOING THE RH. OUTSIDE OF SOME LIGHT SHOWERS...THINK CONDITIONS
WILL TEND TO BE VFR. ONLY EXCEPTION WOULD BE IF WE CLEAR OUT. THEN
THERE COULD BE SOME RADIATIONAL FOG...BUT THINK THE CLOUDS WILL HANG
IN UNTIL AFTER SUNRISE. FROPA SHOULD OCCUR IN THE EARLY TO MID
AFTERNOON. SOME OF THE HIGH RES SOLUTIONS SHOW SOME WEAK POP UP
SHOWERS POSSIBLE UNTIL THE FRONT MOVES THROUGH. THE HRRR SEEMS TO BE
DOING THE BEST WITH THIS MORNINGS PRECIP AND TAKES MOST OF THE
ACTIVITY EAST OF TOP AND FOE BY 15Z. SO WILL KEEP A DRY FORECAST DUE
TO LOW CONFIDENCE IN LOCATION OF ANY ISOLATED SHOWER ACTIVITY THIS
AFTERNOON.
WOLTERS
&&
.PREV DISCUSSION... /415 AM CDT SAT MAR 30 2013/
WATER VAPOR IMAGERY SHOWING ONE SHORTWAVE TROUGH OVER NE MOVING
SOUTHEAST WITH CONVECTION OUT AHEAD OF IT WITHIN WAA REGIME ACROSS
SOUTHERN NE INTO CENTRAL KS. THIS AREA OF CONVECTION WILL CONTINUE
TO MOVE EAST AND SOUTHEAST ACROSS THE CWA THROUGH SUNRISE BEFORE
DIMINISHING. A COLD FRONT OVER CENTRAL NE WILL MOVE SOUTHEAST ACROSS
THE CWA THROUGH THE MIDDAY/AFTERNOON HOURS. IF SUFFICIENT
HEATING/DESTABILIZATION IN THE WAKE OF THIS MORNINGS ACTIVITY
OCCURS...MUCAPES OF 1500-2000 J/KG ARE POSSIBLE ACROSS THE SOUTHEAST
CWA...PRIMARILY ALONG AND SOUTHEAST OF THE I 35 CORRIDOR AT THE TIME
OF THE FROPA. IF ANY ISOLATED TO SCATTERED CONVECTION IS ABLE TO
REDEVELOP ALONG/AHEAD OF THE FRONT WITHIN THIS ENVIRONMENT...THEY
MAY BECOME CAPABLE OF PRODUCING SOME HAIL TO QUARTER SIZE AND STRONG
GUSTY WINDS. THIS ACTIVITY WOULD LIKELY EXIT THE FAR SOUTHEAST CWA
BY EARLY EVENING...ALTHOUGH MORE POST FRONTAL SHOWERS COULD STILL
REDEVELOP FURTHER TOWARDS THE NORTHWEST IN ADVANCE OF THE SHORTWAVE
TROUGH CURRENTLY MOVING INTO WY. ANY SHOWERS ASSOCIATED WITH THIS
SHOULD DISSIPATE BY MIDNIGHT...LEAVING THE REMAINDER OF NIGHT DRY
AND COOLER.
SUNDAY STILL LOOKING DRY AND MILD WITH HIGHS GENERALLY 65 TO 70 IN
ADVANCE OF THE NEXT MUCH STRONGER COLD FRONT TO THE NORTH. THIS
FRONT WILL PASS THROUGH THE CWA NORTH TO SOUTH THROUGH THE EVENING
WITH A CHANCE FOR RAIN...THEN A CHANCE FOR RAIN OR SNOW OVERNIGHT
INTO MONDAY AS THE COLDER AIR PLUNGES SOUTHWARD. ANY SNOWFALL APPEAR
SHOULD PRIMARILY BE UNDER HALF AN INCH AT THIS TIME. THE WINTRY MIX
POTENTIAL WILL SHIFT TO THE SOUTHERN CWA THROUGH AFTERNOON THEN END
BY EVENING...BUT AGAIN AMOUNTS SHOULD BE VERY LIGHT.
MODELS STILL KEEPING THE NEXT TROUGH IN THE ROCKIES TO THE SOUTH OF
THE AREA THROUGH MID WEEK WITH DRY CONDITIONS AND A GRADUAL
MODERATION IN TEMPS AS THE AREA GRADUALLY TRANSITIONS FROM NORTHWEST
FLOW ALOFT TO A MORE ZONAL FLOW. HIGHS SHOULD RISE FROM NEAR 40 ON
MONDAY TO THE 50S BY WEDNESDAY...THEN THE 60S AGAIN BY FRIDAY. LOWS
IN THE 20S EARLY IN THE WEEK SHOULD RISE TO NEAR 40 BY FRIDAY. 63
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1000 PM EDT SUN MAR 31 2013
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL MOVE ACROSS SOUTHERN VIRGINIA AND
NORTHEAST NORTH CAROLINA LATER TONIGHT INTO EARLY MONDAY. WARM
AND BREEZY CONDITIONS WILL PREVAIL MONDAY AHEAD OF AN APPROACHING
COLD FRONT. THIS FRONT WILL CROSS THE REGION MONDAY NIGHT...FOLLOWED
BY MUCH COOLER AND DRY WEATHER TUESDAY AND WEDNESDAY...AS HIGH
PRESSURE BUILDS INTO THE AREA FROM THE NORTHWEST.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
LATEST WX ANALYSIS DEPICTS A WARM FRONT NORTH OF THE AREA...AND A
SFC TROUGH OF LOW PRESSURE (OR A WEAK COLD FRONT) TO THE LEE OF
THE MTNS. MODELS SHOW THIS SFC TROUGH SETTING UP OVER FAR SOUTHERN
VA AND NE NC LATER TONIGHT AND GIVEN ZONAL/WESTERLY FLOW ALOFT PER
LATEST 00Z SOUNDINGS EXPECT THE BOUNDARY TO BE SLOW TO PUSH SOUTH
OVERNIGHT. LATEST RADAR SHOWS A FAIR AMOUNT OF SHOWER ACTIVITY
ACRS NORTH CENTRAL NC MOVING EAST AND EXPECTED TO AFFECT OUR FAR
SOUTHERN VA AND NE NC COUNTIES OVER THE NEXT FEW HRS. HAVE RAISED
POPS FOR THE REMAINDER OF THE EVENING/EARLY AM HRS TO HIGH CHANCE
OR LIKELY ACRS THESE ZONES. MEANWHILE...SKIES ARE STARTING TO
CLEAR OVER NORTHERN PORTIONS OF THE CWA...AND SOME PATCHY FOG IS
DEVELOPING. WITH THE LOW LEVEL FLOW GENLY BEING RATHER
LIGHT...WILL CONTINUE TO SEE FOG DEVELOPMENT SLOWLY SPREAD SOUTH
ALTHOUGH NOT SURE HOW FAR SOUTH IT GETS AS CLOUDS ACRS SOUTHERN
ZONES WILL BE SLOW TO CLEAR OVERNIGHT. LATEST RUC AND NAM12
SOUNDINGS SHOW THIS POTENTIAL ESPECIALLY FROM 06-09Z SO HAVE ADDED
PATCHY FOG TO PORTIONS OF CENTRAL VA AND THE MD ERN SHORE. LITTLE
UPDATE TO OVERNIGHT TEMPERATURE FORECAST...LOWS 40-45 FAR
NORTH...45-50 ACRS MOST OF THE CWA AND LOWER 50S IN NE NC WHERE
SKIES STAY CLOUDY WITH MORE MIXING THROUGH THE NIGHT.
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
SOME BRIEF CLEARING WILL TAKE PLACE MONDAY AHEAD OF THE NEXT STRONG
COLD FRONT THAT WILL MOVE THROUGH MONDAY NIGHT. THE MAJOR IMPACT OF
THIS FRONT WILL BE THE SHOT OF COLDER AIR IT BRINGS TO THE MID-
ATLANTIC. DUE TO THE LIMITED MOISTURE AVAILABLE...ONLY A SLIGHT
CHANCE/20% FOR A BRIEF PERIOD OF SHOWERS EXPECTED WITH AN AREA OF
CONVERGENCE AHEAD OF THE FRONT LATE MON AFTN INTO MONDAY NIGHT.
WINDS WILL SHIFT TO THE N/NW BEHIND THE FRONT USHERING IN THE
COLDER AIR.
DRIER/COOLER AIR WILL BE MAINTAINED THROUGH WED DUE TO MID LEVEL
FLOW OUT OF THE WNW-NW AND HIGH PRESSURE MOVING E FROM THE
NORTHERN PLAINS KEEPS A PERSISTENT...COOLER W/WNW FLOW AT THE SURFACE.
PARTY CLOUDY CONDITIONS WILL PREVAIL DUE SHORT WAVES MOVING ACROSS
THE MID-ATLANTIC TUE AND WED.
HIGH TEMPS WILL RANGE FROM THE LOWER 70S SOUTH TO MID 60S NORTH
FOR MON...COOLING INTO THE LOW TO MID 50S FOR TUE AND WED. LOW
TEMPS TUE MORNING WILL BE ~40 ACROSS NE NC AND IN THE LOWER TO MID
30S WELL INLAND.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
SOME BRIEF CLEARING WILL TAKE PLACE MONDAY AHEAD OF THE NEXT STRONG
COLD FRONT THAT WILL MOVE THROUGH MONDAY NIGHT. THE MAJOR IMPACT OF
THIS FRONT WILL BE THE SHOT OF COLDER AIR IT BRINGS TO THE MID-
ATLANTIC. DUE TO THE LIMITED MOISTURE AVAILABLE...ONLY A SLIGHT
CHANCE/20% FOR A BRIEF PERIOD OF SHOWERS EXPECTED WITH AN AREA OF
CONVERGENCE AHEAD OF THE FRONT LATE MON AFTN INTO MONDAY NIGHT.
WINDS WILL SHIFT TO THE N/NW BEHIND THE FRONT USHERING IN THE
COLDER AIR.
DRIER/COOLER AIR WILL BE MAINTAINED THROUGH WED DUE TO MID LEVEL
FLOW OUT OF THE WNW-NW AND HIGH PRESSURE MOVING E FROM THE
NORTHERN PLAINS KEEPS A PERSISTENT...COOLER W/WNW FLOW AT THE SURFACE.
PARTY CLOUDY CONDITIONS WILL PREVAIL DUE SHORT WAVES MOVING ACROSS
THE MID-ATLANTIC TUE AND WED.
HIGH TEMPS WILL RANGE FROM THE LOWER 70S SOUTH TO MID 60S NORTH
FOR MON...COOLING INTO THE LOW TO MID 50S FOR TUE AND WED. LOW
TEMPS TUE MORNING WILL BE ~40 ACROSS NE NC AND IN THE LOWER TO MID
30S WELL INLAND.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AN UPPER LEVEL TROUGH OF COLDER CANADIAN AIR SLOWLY MOVES ACROSS
THE NE CONUS ON THU AS SFC HIGH PRESSURE CROSSES THE MID ATLANTIC
STATES. EXPECT MORNING LOWS IN THE 30S (NEAR 40 IMMEDIATE COAST)
AND HIGHS IN THE MID TO UPPER 50S (NEAR 50 IMMEDIATE COAST). THE
SFC HIGH MOVES OFF THE COAST BY THU NIGHT...CAUSING WINDS TO
BECOME ONSHORE/SELY AND ALSO CREATING THE POTENTIAL FOR A COLD AIR
WEDGE TO DEVELOP OVER NW PORTIONS OF THE FA. A LOW PRESSURE SYSTEM
PASSING ACROSS THE GULF COAST STATES FROM TX TO FL DURING THE
MIDDLE OF THE WEEK IS STILL EXPECTED TO LIFT NORTH TWD THE MID
ATLANTIC STATES THU NIGHT INTO FRI. IT IS TOO SOON TO DETERMINE
THE EXACT TRACK OF THIS SYSTEM OR HOW MUCH IT WILL IMPACT THE
REGION DUE TO TIMING/PLACEMENT DIFFERENCES AMONG EXTENDED MODELS.
THE GFS IS FASTER/MORE PROGRESSIVE WHILE THE ECMWF IS SLOWER. HAVE
CONTINUED A GENERAL INCREASE IN PRECIP DURING THIS TIMEFRAME WITH
PRECIP SHUTTING OFF QUICKLY BEHIND THE DEPARTING SYSTEM. P-TYPE
APPEARS TO BE ALL RAIN AT THIS TIME REGARDLESS OF MODEL
DIFFERENCES. HAVE COOLED TEMPERATURES A FEW DEGREES FOR FRI OVER
NW PORTIONS OF THE FA DUE TO THE POSSIBLE COLD AIR WEDGE. HIGH
PRESSURE RETURNS TO THE AREA ON SAT...FOLLOWED BY A LOW PRESSURE
SYSTEM CROSSING THE UPPER OH VALLEY AND ERN GREAT LAKES REGION ON
SUN. THIS SYSTEM IS EXPECTED TO DRAG A COLD FRONT ACROSS THE AREA
SUN NIGHT INTO MON...ONLY A SLIGHT CHANCE FOR PRECIP OVER FAR NW
COUNTIES OF FA IN VA AND MD ATTM.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
CLOUD CEILINGS HAVE IMPROVED TO MOSTLY VFR ACROSS THE REGION.
SATELLITE AND RADAR SHOWING AREA OF RAIN OVER NC MOVG EAST AND
LIKELY TO AFFECT ECG AND PSBLY ORF THRU MIDNIGHT. WNDS GENERALLY
SW-WSW 5 TO 10 KT TONIGHT. SOME PTCHY FOG STARTING TO DEVELOP IN
WESTERN PORTIONS OF THE CWA. WENT WITH 3-4 MILES VISBILITY AND FOG
FOR TAF SITES BUT WOULD NOT BE SURPRISED TO GET PERIOD OF IFR
OVERNIGHT. EXPECT OCNL -RA TONIGHT FOR ECG WITH CIGS PSBLY DOWN TO
MVFR. CONFIDENCE LOW FOR ANY DENSE FOG DEVELOPMENT.
FRONTL BNDRY WILL PUSH THRU THE REGION OVERNIGHT AND INTO FAR SE
VA/NE NC BY MORNING. WEAK WAVES ALONG THE BNDRY WILL CONT TO BRING
CHC OF -RA IN SOUTHERN PORTIONS OVERNIGHT AND FOR ENTIRE CWA MON.
EXPECT MVFR/VFR CONDS ON MON WITH CHC OF SCT RAIN THRU THE DAY.
ANOTHER FRONT MOVES THRU MON EVENING. HI PRES THEN BUILDS INTO THE
REGION FOR TUE AND WED WITH VFR CONDS.
&&
.MARINE...
UPDATE...SCA FLAGS FOR SRN CHES BAY ALLOWED TO EXPIRE AT 6 PM EDT
THIS EVENING. WINDS HAVE SUBSIDED TO SPEEDS AOB 15 KT.
PREVIOUS DISCUSSION...A WARM FRONT WILL SLOWLY LIFT NWD OVER CTRL
AND NRN WATERS THROUGH THIS EVENING. A COLD FRONT THEN CROSSES
THE WATERS LATER TONIGHT. OCCASIONAL WIND GUSTS OF 20-30 KT MAY BE
POSSIBLE DURING THE FRONTAL PASSAGE AND WILL COVER THIS POTENTIAL
HAZARD WITH MWW OR SMW HEADLINES IF NEEDED. BEHIND THE COLD
FRONT...WINDS TO SWITCH TO THE W. SPEEDS ARE EXPECTED TO REMAIN
AOB 15 KT DUE TO LACK OF CAA...THEN BECOME SWLY ON MON AS THE
FRONT STALLS OVER THE CAROLINAS. A STRONGER FRONTAL BOUNDARY
ASSOCIATED WITH AN UPPER LEVEL TROUGH OVER THE NE U.S. WILL CROSS
THE WATERS OVERNIGHT MON NIGHT INTO TUE...FOLLOWED BY MUCH COLDER
AIR THROUGH AT LEAST WED. NW-N WINDS SHOULD AVERAGE AROUND 15-20
KT WITH GUSTS UP TO 30 KT OVER THE BAY AND COASTAL WATERS. BEST
CHANCES FOR SCA FLAGS CONTINUE TO BE MON NIGHT WITH THE FIRST
SURGE OF COLD AIR/CAA...AND THEN AGAIN ON TUE NIGHT INTO WED
MORNING. 12Z MODEL RUNS HAVE BACKED OFF A LITTLE BIT ON THE
OVERALL STRENGTH OF WINDS THAT CAN MIX DOWN ON MON NIGHT...AND
HAVE DECIDED TO HOLD OFF ON ISSUING SCA HEADLINES ATTM. HIGH
PRESSURE THEN BUILDS OVER THE MID ATLANTIC REGION WED INTO WED
NIGHT...SLIDING OFF THE COAST ON THU. A MORE ROBUST LOW PRESSURE
SYSTEM APPROACHES THE MID ATLANTIC REGION THU NIGHT AND MOVES
ACROSS THE WATERS FRI INTO FRI NIGHT. SCA FLAGS WILL LIKELY BE
NEEDED FOR THIS SYSTEM AS WELL. STAY TUNED.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LKB
NEAR TERM...LKB/DAP
SHORT TERM...DAP
LONG TERM...BMD
AVIATION...JEF
MARINE...BMD
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
929 PM EDT SUN MAR 31 2013
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL MOVE ACROSS SOUTHERN VIRGINIA AND
NORTHEAST NORTH CAROLINA LATER TONIGHT INTO EARLY MONDAY. WARM
AND BREEZY CONDITIONS WILL PREVAIL MONDAY AHEAD OF AN APPROACHING
COLD FRONT. THIS FRONT WILL CROSS THE REGION MONDAY NIGHT...FOLLOWED
BY MUCH COOLER AND DRY WEATHER TUESDAY AND WEDNESDAY...AS HIGH
PRESSURE BUILDS INTO THE AREA FROM THE NORTHWEST.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
LATEST WX ANALYSIS DEPICTS A WARM FRONT NORTH OF THE AREA...AND A
SFC TROUGH OF LOW PRESSURE (OR A WEAK COLD FRONT) TO THE LEE OF
THE MTNS. MODELS SHOW THIS SFC TROUGH SETTING UP OVER FAR SOUTHERN
VA AND NE NC LATER TONIGHT AND GIVEN ZONAL/WESTERLY FLOW ALOFT PER
LATEST 00Z SOUNDINGS EXPECT THE BOUNDARY TO BE SLOW TO PUSH SOUTH
OVERNIGHT. LATEST RADAR SHOWS A FAIR AMOUNT OF SHOWER ACTIVITY
ACRS NORTH CENTRAL NC MOVING EAST AND EXPECTED TO AFFECT OUR FAR
SOUTHERN VA AND NE NC COUNTIES OVER THE NEXT FEW HRS. HAVE RAISED
POPS FOR THE REMAINDER OF THE EVENING TO HIGH CHANCE ACRS THESE
ZONES. MEANWHILE...SKIES ARE STARTING TO CLEAR OVER NW PORTIONS OF
THE CWA...AND WITH THE LOW LEVEL FLOW GENLY BEING RATHER
LIGHT...SHOULD SEE SOME FOG DEVELOPMENT OVER THE NEXT FEW HRS ACRS
NORTHERN AREAS. LATEST RUC AND NAM12 SOUNDINGS SHOW THIS POTENTIAL
ESPECIALLY FROM 06-09Z SO HAVE ADDED PATCHY FOG TO PORTIONS OF
CENTRAL VA AND THE MD ERN SHORE. LITTLE UPDATE TO OVERNIGHT
TEMPERATURE FORECAST...LOWS 40-45 FAR NORTH...45-50 ACRS MOST OF
THE CWA AND LOWER 50S IN NE NC WHERE SKIES STAY CLOUDY WITH MORE
MIXING THROUGH THE NIGHT.
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
SOME BRIEF CLEARING WILL TAKE PLACE MONDAY AHEAD OF THE NEXT STRONG
COLD FRONT THAT WILL MOVE THROUGH MONDAY NIGHT. THE MAJOR IMPACT OF
THIS FRONT WILL BE THE SHOT OF COLDER AIR IT BRINGS TO THE MID-
ATLANTIC. DUE TO THE LIMITED MOISTURE AVAILABLE...ONLY A SLIGHT
CHANCE/20% FOR A BRIEF PERIOD OF SHOWERS EXPECTED WITH AN AREA OF
CONVERGENCE AHEAD OF THE FRONT LATE MON AFTN INTO MONDAY NIGHT.
WINDS WILL SHIFT TO THE N/NW BEHIND THE FRONT USHERING IN THE
COLDER AIR.
DRIER/COOLER AIR WILL BE MAINTAINED THROUGH WED DUE TO MID LEVEL
FLOW OUT OF THE WNW-NW AND HIGH PRESSURE MOVING E FROM THE
NORTHERN PLAINS KEEPS A PERSISTENT...COOLER W/WNW FLOW AT THE SURFACE.
PARTY CLOUDY CONDITIONS WILL PREVAIL DUE SHORT WAVES MOVING ACROSS
THE MID-ATLANTIC TUE AND WED.
HIGH TEMPS WILL RANGE FROM THE LOWER 70S SOUTH TO MID 60S NORTH
FOR MON...COOLING INTO THE LOW TO MID 50S FOR TUE AND WED. LOW
TEMPS TUE MORNING WILL BE ~40 ACROSS NE NC AND IN THE LOWER TO MID
30S WELL INLAND.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
SOME BRIEF CLEARING WILL TAKE PLACE MONDAY AHEAD OF THE NEXT STRONG
COLD FRONT THAT WILL MOVE THROUGH MONDAY NIGHT. THE MAJOR IMPACT OF
THIS FRONT WILL BE THE SHOT OF COLDER AIR IT BRINGS TO THE MID-
ATLANTIC. DUE TO THE LIMITED MOISTURE AVAILABLE...ONLY A SLIGHT
CHANCE/20% FOR A BRIEF PERIOD OF SHOWERS EXPECTED WITH AN AREA OF
CONVERGENCE AHEAD OF THE FRONT LATE MON AFTN INTO MONDAY NIGHT.
WINDS WILL SHIFT TO THE N/NW BEHIND THE FRONT USHERING IN THE
COLDER AIR.
DRIER/COOLER AIR WILL BE MAINTAINED THROUGH WED DUE TO MID LEVEL
FLOW OUT OF THE WNW-NW AND HIGH PRESSURE MOVING E FROM THE
NORTHERN PLAINS KEEPS A PERSISTENT...COOLER W/WNW FLOW AT THE SURFACE.
PARTY CLOUDY CONDITIONS WILL PREVAIL DUE SHORT WAVES MOVING ACROSS
THE MID-ATLANTIC TUE AND WED.
HIGH TEMPS WILL RANGE FROM THE LOWER 70S SOUTH TO MID 60S NORTH
FOR MON...COOLING INTO THE LOW TO MID 50S FOR TUE AND WED. LOW
TEMPS TUE MORNING WILL BE ~40 ACROSS NE NC AND IN THE LOWER TO MID
30S WELL INLAND.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AN UPPER LEVEL TROUGH OF COLDER CANADIAN AIR SLOWLY MOVES ACROSS
THE NE CONUS ON THU AS SFC HIGH PRESSURE CROSSES THE MID ATLANTIC
STATES. EXPECT MORNING LOWS IN THE 30S (NEAR 40 IMMEDIATE COAST)
AND HIGHS IN THE MID TO UPPER 50S (NEAR 50 IMMEDIATE COAST). THE
SFC HIGH MOVES OFF THE COAST BY THU NIGHT...CAUSING WINDS TO
BECOME ONSHORE/SELY AND ALSO CREATING THE POTENTIAL FOR A COLD AIR
WEDGE TO DEVELOP OVER NW PORTIONS OF THE FA. A LOW PRESSURE SYSTEM
PASSING ACROSS THE GULF COAST STATES FROM TX TO FL DURING THE
MIDDLE OF THE WEEK IS STILL EXPECTED TO LIFT NORTH TWD THE MID
ATLANTIC STATES THU NIGHT INTO FRI. IT IS TOO SOON TO DETERMINE
THE EXACT TRACK OF THIS SYSTEM OR HOW MUCH IT WILL IMPACT THE
REGION DUE TO TIMING/PLACEMENT DIFFERENCES AMONG EXTENDED MODELS.
THE GFS IS FASTER/MORE PROGRESSIVE WHILE THE ECMWF IS SLOWER. HAVE
CONTINUED A GENERAL INCREASE IN PRECIP DURING THIS TIMEFRAME WITH
PRECIP SHUTTING OFF QUICKLY BEHIND THE DEPARTING SYSTEM. P-TYPE
APPEARS TO BE ALL RAIN AT THIS TIME REGARDLESS OF MODEL
DIFFERENCES. HAVE COOLED TEMPERATURES A FEW DEGREES FOR FRI OVER
NW PORTIONS OF THE FA DUE TO THE POSSIBLE COLD AIR WEDGE. HIGH
PRESSURE RETURNS TO THE AREA ON SAT...FOLLOWED BY A LOW PRESSURE
SYSTEM CROSSING THE UPPER OH VALLEY AND ERN GREAT LAKES REGION ON
SUN. THIS SYSTEM IS EXPECTED TO DRAG A COLD FRONT ACROSS THE AREA
SUN NIGHT INTO MON...ONLY A SLIGHT CHANCE FOR PRECIP OVER FAR NW
COUNTIES OF FA IN VA AND MD ATTM.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
CLOUD CEILINGS HAVE IMPROVED TO MOSTLY VFR ACROSS THE REGION.
SATELLITE AND RADAR SHOWING AREA OF RAIN OVER NC MOVG EAST AND
LIKELY TO AFFECT ECG AND PSBLY ORF THRU MIDNIGHT. WNDS GENERALLY
SW-WSW 5 TO 10 KT TONIGHT. SOME PTCHY FOG STARTING TO DEVELOP IN
WESTERN PORTIONS OF THE CWA. WENT WITH 3-4 MILES VISBILITY AND FOG
FOR TAF SITES BUT WOULD NOT BE SURPRISED TO GET PERIOD OF IFR
OVERNIGHT. EXPECT OCNL -RA TONIGHT FOR ECG WITH CIGS PSBLY DOWN TO
MVFR. CONFIDENCE LOW FOR ANY DENSE FOG DEVELOPMENT.
FRONTL BNDRY WILL PUSH THRU THE REGION OVERNIGHT AND INTO FAR SE
VA/NE NC BY MORNING. WEAK WAVES ALONG THE BNDRY WILL CONT TO BRING
CHC OF -RA IN SOUTHERN PORTIONS OVERNIGHT AND FOR ENTIRE CWA MON.
EXPECT MVFR/VFR CONDS ON MON WITH CHC OF SCT RAIN THRU THE DAY.
ANOTHER FRONT MOVES THRU MON EVENING. HI PRES THEN BUILDS INTO THE
REGION FOR TUE AND WED WITH VFR CONDS.
&&
.MARINE...
UPDATE...SCA FLAGS FOR SRN CHES BAY ALLOWED TO EXPIRE AT 6 PM EDT
THIS EVENING. WINDS HAVE SUBSIDED TO SPEEDS AOB 15 KT.
PREVIOUS DISCUSSION...A WARM FRONT WILL SLOWLY LIFT NWD OVER CTRL
AND NRN WATERS THROUGH THIS EVENING. A COLD FRONT THEN CROSSES
THE WATERS LATER TONIGHT. OCCASIONAL WIND GUSTS OF 20-30 KT MAY BE
POSSIBLE DURING THE FRONTAL PASSAGE AND WILL COVER THIS POTENTIAL
HAZARD WITH MWW OR SMW HEADLINES IF NEEDED. BEHIND THE COLD
FRONT...WINDS TO SWITCH TO THE W. SPEEDS ARE EXPECTED TO REMAIN
AOB 15 KT DUE TO LACK OF CAA...THEN BECOME SWLY ON MON AS THE
FRONT STALLS OVER THE CAROLINAS. A STRONGER FRONTAL BOUNDARY
ASSOCIATED WITH AN UPPER LEVEL TROUGH OVER THE NE U.S. WILL CROSS
THE WATERS OVERNIGHT MON NIGHT INTO TUE...FOLLOWED BY MUCH COLDER
AIR THROUGH AT LEAST WED. NW-N WINDS SHOULD AVERAGE AROUND 15-20
KT WITH GUSTS UP TO 30 KT OVER THE BAY AND COASTAL WATERS. BEST
CHANCES FOR SCA FLAGS CONTINUE TO BE MON NIGHT WITH THE FIRST
SURGE OF COLD AIR/CAA...AND THEN AGAIN ON TUE NIGHT INTO WED
MORNING. 12Z MODEL RUNS HAVE BACKED OFF A LITTLE BIT ON THE
OVERALL STRENGTH OF WINDS THAT CAN MIX DOWN ON MON NIGHT...AND
HAVE DECIDED TO HOLD OFF ON ISSUING SCA HEADLINES ATTM. HIGH
PRESSURE THEN BUILDS OVER THE MID ATLANTIC REGION WED INTO WED
NIGHT...SLIDING OFF THE COAST ON THU. A MORE ROBUST LOW PRESSURE
SYSTEM APPROACHES THE MID ATLANTIC REGION THU NIGHT AND MOVES
ACROSS THE WATERS FRI INTO FRI NIGHT. SCA FLAGS WILL LIKELY BE
NEEDED FOR THIS SYSTEM AS WELL. STAY TUNED.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LKB
NEAR TERM...LKB/DAP
SHORT TERM...DAP
LONG TERM...BMD
AVIATION...JEF
MARINE...BMD
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
859 PM EDT SUN MAR 31 2013
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL MOVE ACROSS SOUTHERN VIRGINIA AND
NORTHEAST NORTH CAROLINA LATER TONIGHT INTO EARLY MONDAY. WARM
AND BREEZY CONDITIONS WILL PREVAIL MONDAY AHEAD OF AN APPROACHING
COLD FRONT. THIS FRONT WILL CROSS THE REGION MONDAY NIGHT...FOLLOWED
BY MUCH COOLER AND DRY WEATHER TUESDAY AND WEDNESDAY...AS HIGH
PRESSURE BUILDS INTO THE AREA FROM THE NORTHWEST.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
LATEST WX ANALYSIS DEPICTS A WARM FRONT NORTH OF THE AREA...AND A
SFC TROUGH OF LOW PRESSURE (OR A WEAK COLD FRONT) TO THE LEE OF
THE MTNS. MODELS SHOW THIS SFC TROUGH SETTING UP OVER FAR SOUTHERN
VA AND NE NC LATER TONIGHT AND GIVEN ZONAL/WESTERLY FLOW ALOFT PER
LATEST 00Z SOUNDINGS EXPECT THE BOUNDARY TO BE SLOW TO PUSH SOUTH
OVERNIGHT. LATEST RADAR SHOWS A FAIR AMOUNT OF SHOWER ACTIVITY
ACRS NORTH CENTRAL NC MOVING EAST AND EXPECTED TO AFFECT OUR FAR
SOUTHERN VA AND NE NC COUNTIES OVER THE NEXT FEW HRS. HAVE RAISED
POPS FOR THE REMAINDER OF THE EVENING TO HIGH CHANCE ACRS THESE
ZONES. MEANWHILE...SKIES ARE STARTING TO CLEAR OVER NW PORTIONS OF
THE CWA...AND WITH THE LOW LEVEL FLOW GENLY BEING RATHER
LIGHT...SHOULD SEE SOME FOG DEVELOPMENT OVER THE NEXT FEW HRS ACRS
NORTHERN AREAS. LATEST RUC AND NAM12 SOUNDINGS SHOW THIS POTENTIAL
ESPECIALLY FROM 06-09Z SO HAVE ADDED PATCHY FOG TO PORTIONS OF
CENTRAL VA AND THE MD ERN SHORE. LITTLE UPDATE TO OVERNIGHT
TEMPERATURE FORECAST...LOWS 40-45 FAR NORTH...45-50 ACRS MOST OF
THE CWA AND LOWER 50S IN NE NC WHERE SKIES STAY CLOUDY WITH MORE
MIXING THROUGH THE NIGHT.
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
SOME BRIEF CLEARING WILL TAKE PLACE MONDAY AHEAD OF THE NEXT STRONG
COLD FRONT THAT WILL MOVE THROUGH MONDAY NIGHT. THE MAJOR IMPACT OF
THIS FRONT WILL BE THE SHOT OF COLDER AIR IT BRINGS TO THE MID-
ATLANTIC. DUE TO THE LIMITED MOISTURE AVAILABLE...ONLY A SLIGHT
CHANCE/20% FOR A BRIEF PERIOD OF SHOWERS EXPECTED WITH AN AREA OF
CONVERGENCE AHEAD OF THE FRONT LATE MON AFTN INTO MONDAY NIGHT.
WINDS WILL SHIFT TO THE N/NW BEHIND THE FRONT USHERING IN THE
COLDER AIR.
DRIER/COOLER AIR WILL BE MAINTAINED THROUGH WED DUE TO MID LEVEL
FLOW OUT OF THE WNW-NW AND HIGH PRESSURE MOVING E FROM THE
NORTHERN PLAINS KEEPS A PERSISTENT...COOLER W/WNW FLOW AT THE SURFACE.
PARTY CLOUDY CONDITIONS WILL PREVAIL DUE SHORT WAVES MOVING ACROSS
THE MID-ATLANTIC TUE AND WED.
HIGH TEMPS WILL RANGE FROM THE LOWER 70S SOUTH TO MID 60S NORTH
FOR MON...COOLING INTO THE LOW TO MID 50S FOR TUE AND WED. LOW
TEMPS TUE MORNING WILL BE ~40 ACROSS NE NC AND IN THE LOWER TO MID
30S WELL INLAND.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AN UPPER LEVEL TROUGH OF COLDER CANADIAN AIR SLOWLY MOVES ACROSS
THE NE CONUS ON THU AS SFC HIGH PRESSURE CROSSES THE MID ATLANTIC
STATES. EXPECT MORNING LOWS IN THE 30S (NEAR 40 IMMEDIATE COAST)
AND HIGHS IN THE MID TO UPPER 50S (NEAR 50 IMMEDIATE COAST). THE
SFC HIGH MOVES OFF THE COAST BY THU NIGHT...CAUSING WINDS TO
BECOME ONSHORE/SELY AND ALSO CREATING THE POTENTIAL FOR A COLD AIR
WEDGE TO DEVELOP OVER NW PORTIONS OF THE FA. A LOW PRESSURE SYSTEM
PASSING ACROSS THE GULF COAST STATES FROM TX TO FL DURING THE
MIDDLE OF THE WEEK IS STILL EXPECTED TO LIFT NORTH TWD THE MID
ATLANTIC STATES THU NIGHT INTO FRI. IT IS TOO SOON TO DETERMINE
THE EXACT TRACK OF THIS SYSTEM OR HOW MUCH IT WILL IMPACT THE
REGION DUE TO TIMING/PLACEMENT DIFFERENCES AMONG EXTENDED MODELS.
THE GFS IS FASTER/MORE PROGRESSIVE WHILE THE ECMWF IS SLOWER. HAVE
CONTINUED A GENERAL INCREASE IN PRECIP DURING THIS TIMEFRAME WITH
PRECIP SHUTTING OFF QUICKLY BEHIND THE DEPARTING SYSTEM. P-TYPE
APPEARS TO BE ALL RAIN AT THIS TIME REGARDLESS OF MODEL
DIFFERENCES. HAVE COOLED TEMPERATURES A FEW DEGREES FOR FRI OVER
NW PORTIONS OF THE FA DUE TO THE POSSIBLE COLD AIR WEDGE. HIGH
PRESSURE RETURNS TO THE AREA ON SAT...FOLLOWED BY A LOW PRESSURE
SYSTEM CROSSING THE UPPER OH VALLEY AND ERN GREAT LAKES REGION ON
SUN. THIS SYSTEM IS EXPECTED TO DRAG A COLD FRONT ACROSS THE AREA
SUN NIGHT INTO MON...ONLY A SLIGHT CHANCE FOR PRECIP OVER FAR NW
COUNTIES OF FA IN VA AND MD ATTM.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
MANAGED IFR CONDS FOR A PD AT RIC SO FAR...LO PROB FOR SBY IN THE
NEXT FEW HRS AS RA CONTS TO MOVE TO THE E REACHING THE CST.
OTRW...DRYING EVIDENT ON VSBL IMAGERY ENTERING SRN VA/NE NC W/
ANY CIGS RISING TO 5KFT AND ABV. WNDS BECOMING MORE SSW AS WELL.
TRAILING SFC TROUGH TO CROSS THE RGN THIS EVE W/ PSBL SCT-BKN CIGS
(GENLY ABV 3KFT) AND PTNTLLY ISOLD/SCT CNVTN. LO PROB FOR MVFR/IFR
IN CIGS/FG LT TNGT/ERY MON (AFT RA TDA...AND RELATIVE LGT WNDS AFT
MDNGT). VFR CONDS MON AHD OF APPROACHING CDFNT. MDLS CONTG W/
TREND OF DCRSG MSTR ASSOCIATED W/ THAT FNTL PASSAGE MON NGT
(TSECTIONS SUGGEST ANY CIGS 5-10KFT). SFC HI PRES BUILDING INTO
THE RGN MIDWEEK RESULTS IN VFR CONDS.
&&
.MARINE...
UPDATE...SCA FLAGS FOR SRN CHES BAY ALLOWED TO EXPIRE AT 6 PM EDT
THIS EVENING. WINDS HAVE SUBSIDED TO SPEEDS AOB 15 KT.
PREVIOUS DISCUSSION...A WARM FRONT WILL SLOWLY LIFT NWD OVER CTRL
AND NRN WATERS THROUGH THIS EVENING. A COLD FRONT THEN CROSSES
THE WATERS LATER TONIGHT. OCCASIONAL WIND GUSTS OF 20-30 KT MAY BE
POSSIBLE DURING THE FRONTAL PASSAGE AND WILL COVER THIS POTENTIAL
HAZARD WITH MWW OR SMW HEADLINES IF NEEDED. BEHIND THE COLD
FRONT...WINDS TO SWITCH TO THE W. SPEEDS ARE EXPECTED TO REMAIN
AOB 15 KT DUE TO LACK OF CAA...THEN BECOME SWLY ON MON AS THE
FRONT STALLS OVER THE CAROLINAS. A STRONGER FRONTAL BOUNDARY
ASSOCIATED WITH AN UPPER LEVEL TROUGH OVER THE NE U.S. WILL CROSS
THE WATERS OVERNIGHT MON NIGHT INTO TUE...FOLLOWED BY MUCH COLDER
AIR THROUGH AT LEAST WED. NW-N WINDS SHOULD AVERAGE AROUND 15-20
KT WITH GUSTS UP TO 30 KT OVER THE BAY AND COASTAL WATERS. BEST
CHANCES FOR SCA FLAGS CONTINUE TO BE MON NIGHT WITH THE FIRST
SURGE OF COLD AIR/CAA...AND THEN AGAIN ON TUE NIGHT INTO WED
MORNING. 12Z MODEL RUNS HAVE BACKED OFF A LITTLE BIT ON THE
OVERALL STRENGTH OF WINDS THAT CAN MIX DOWN ON MON NIGHT...AND
HAVE DECIDED TO HOLD OFF ON ISSUING SCA HEADLINES ATTM. HIGH
PRESSURE THEN BUILDS OVER THE MID ATLANTIC REGION WED INTO WED
NIGHT...SLIDING OFF THE COAST ON THU. A MORE ROBUST LOW PRESSURE
SYSTEM APPROACHES THE MID ATLANTIC REGION THU NIGHT AND MOVES
ACROSS THE WATERS FRI INTO FRI NIGHT. SCA FLAGS WILL LIKELY BE
NEEDED FOR THIS SYSTEM AS WELL. STAY TUNED.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LKB
NEAR TERM...LKB/DAP
SHORT TERM...DAP
LONG TERM...BMD
AVIATION...ALB
MARINE...BMD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
914 PM EDT SUN MAR 31 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 451 PM EDT SUN MAR 31 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF DEEPENING INTO THE
GREAT LAKES REGION. VIGOROUS SHORTWAVE WAS PASSING OVER LAKE
SUPERIOR. PER SATELLITE IMAGERY AND CANADIAN RADAR IMAGERY...AN
ASSOCIATED IMPRESSIVE LOOKING SMALL SWATH OF MDT TO HVY SNOW HAS
PASSED JUST N OF THE FCST AREA ACROSS FAR NRN LAKE SUPERIOR/ADJACENT
ONTARIO TODAY...ALONG/JUST N OF SHORTWAVE TRACK. AN INCREASINGLY
WELL-DEFINED SFC LOW PRES IS ORGANIZING OVER EASTERN LAKE ATTM PER
VIS SATELLITE IMAGERY. TO THE S...-SHSN TODAY HAVE DEFINITELY TAKEN
ON A SPRINGTIME DIURNAL LAND BASED LOOK WITH UNORGANIZED SCT/NMRS
COVERAGE. WELL-MIXED LAYER HAS PREVENTED SOME OF THE PCPN FROM
REACHING THE GROUND. UPSTREAM 12Z KINL SOUNDING SHOWED A DEEP
MOISTURE PROFILE TO 650MB (AROUND 11KFT)... AND MODIFYING SOUNDING
FOR A SFC T/TD IN THE LWR 30S/LWR 20S YIELDED SBCAPE AROUND
100J/KG...AND THUS THE DIURNAL COMPONENT TO THE -SHSN THIS AFTN.
MAIN FCST ISSUES TONIGHT/MON ARE POTENTIAL LES ACCUMULATIONS AS WELL
AS WINDS. FIRST UP...WINDS. EXPECT STRONGEST WINDS TO OCCUR FROM NOW
THRU THE ABOUT MID EVENING AS AREA OF 4MB/3HR PRES RISES CURRENTLY
JUST NW OF LAKE SUPERIOR SETTLES SE. THE DEEPENING INCREASINGLY
WELL-DEFINED SFC LOW OVER ERN LAKE SUPERIOR IS A CONCERN AS IT WILL
SERVE TO STRENGTHEN ISALLOBARIC WINDS. SOME OF THE HIGHER RES MODEL
GUIDANCE SEEMS TO BE PICKING UP ON THIS AS A SMALL 5-6MB/3HR PRES
RISE MAX DEVELOPS OVER CNTRL/ERN LAKE SUPERIOR WITHIN THE LARGER
SCALE PRES RISES. THE IMPACT OF THE DEEPENING LOW HAS ALREADY MADE
AN IMPACT AS WINDS HAVE GUSTED TO 50MPH AT KP59. THIS SHOULD BE A
GOOD INDICATION OF WHAT IS TO COME IN THE NEXT FEW HRS TO THE E OF
MARQUETTE. WIND ADVY HAS BEEN ISSUED FOR KEWEENAW COUNTY INTO MID
EVENING TO ACCOUNT FOR STRONG WINDS OVER THE NEXT FEW HRS.
AS FOR SNOW...NNW CYCLONIC FLOW SHOULD ALLOW SOME OF THE DEEPER
MOISTURE IN NRN ONTARIO PER 12Z CWPL SOUNDING WHICH SHOWED DEEP
MOISTURE TO 425MB (20500FT) TO SLIP INTO THE UPPER LAKES. WITH 850MB
TEMPS FALLING TO -18C BY 12Z MON...A 3KFT THICK DGZ LAYER FALLS
NICELY INTO THE CONVECTIVE LAYER WHERE NAM INDICATES RATHER VIGOROUS
UPWARD MOTION TONIGHT. WITH EQUILIBRIUM LEVELS LIKELY ABOVE 10KFT...
LES SHOULD GET GOING AT A PRETTY GOOD CLIP...BUT THE LES WILL
LIKELY TAKE SOME TIME TO GET FULLY DEVELOPED AND ORGANIZED AS THE
TYPICAL DISRUPTIVE EFFECTS OF SPRING DAYTIME HEATING ON LES WILL
NEED TO BE ERODED AWAY FIRST. ALTHOUGH IT`S NOT ESPECIALLY COLD
YET...NOTE THAT THE LAKE IS HAVING MORE OF A STABILIZING INFLUENCE
WITH LESS CLOUD OVER THE WATER THAN LAND...EXCEPT RIGHT IN THE VCNTY
OF THE SFC LOW. THE OVERNIGHT PERIOD THRU MON MORNING SHOULD BE THE
PRIME PERIOD OF LES...AND THE GOING ADVY LOOKS ON TRACK FOR THE ERN
COUNTIES ALONG LAKE SUPERIOR. WILL PROBABLY SEE SOME ACCUMULATIONS
UP TO 6-7 INCHES BY MON AFTN. CONSIDERABLE BLSN WILL ALSO BE AN
ISSUE...ESPECIALLY IN OPEN AREAS NEAR LAKE SUPERIOR. THE W WILL BE
MORE ON THE FRINGE OF THE DEEPER MOISTURE PLUS FCST SOUNDINGS SHOW
MORE OF A WELL MIXED BOUNDARY LAYER LINGERING THRU THE NIGHT WHICH
ARGUES FOR LIGHTER LES THAN OVER THE E. ACCUMULATIONS TONIGHT THRU
EARLY MON AFTN SHOULD BE IN THE 1-4 INCH RANGE OVER THE W...
INCLUDING INTO THE HIGHER TERRAIN OF NW MARQUETTE COUNTY.
CONDITIONS REMAIN FAVORABLE FOR LES MON AS 850MB TEMPS ONLY RISE A
DEGREE OR TWO IN THE AFTN. MOISTURE PROFILE REMAINS DEEP OVER THE
E...BUT DOES BECOME MORE SHALLOW OVER THE W. SO LES WILL DIMINISH
OVER THE W. EVEN OVER THE E...EXPECT LES TO BEGIN TO DIMINISH IN THE
AFTN AS STRONG DAYTIME HEATING DISRUPTS LES PROCESSES.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 451 PM EDT SUN MAR 31 2013
LAKE EFFECT WILL BE ONGOING AT THE START OF THE LONGER TERM PERIOD
ON MONDAY NIGHT. INVERSIONS 6-8KFT AND DELTA T/S AROUND 18C WITH
LAKE EQL NEARING 10KFT INDICATE NW FLOW AREAS EAST OF MARQUETTE WILL
CONTINUE TO SEE LIGHT AND MAYBE MODERATE SNOW ACCUMS AND CONTINUING
BLOWING SNOW. HEAVIER SNOW LIKELY OCCURS OVERNIGHT MONDAY NIGHT
THROUGH EARLY TUESDAY MORNING WHEN DIURNAL DISRUPTION IS MINIMAL
AND WHEN LOW-LEVEL CONVERGENCE IS STRONGEST. POSSIBLE THAT MORE
ADVISORIES MAY BE NEEDED MONDAY NIGHT THROUGH TUESDAY MORNING IN
AREAS THAT ARE CURRENTLY IN A HEADLINE.
SFC-H85 FLOW BECOMES INCREASINGLY ANTICYCLONIC TUESDAY WHICH OFFSETS
SUFFICIENT OVER-WATER INSTABILITY AS H85 TEMPS STAY AOB -15C THROUGH
18Z TUESDAY. GFS SOUNDINGS SHOW INVERSION FALLING BLO 5KFT OVR WEST
AFT 12Z AND TO AROUND 5KFT FOR AREAS OVR EASTERN CWA. NO ADDITIONAL
DEEPER MOISTURE AND CYCLONIC FLOW AT A MINIMUM SHOULD COMBINE WITH
HIGHER EARLY APRIL SUN ANGLE/BLYR HEATING TO CONSIDERABLY DISRUPT
LAKE EFFECT BY TUESDAY AFTN. GFS/GEM-NH SLIGHTLY LOWER WITH HEIGHTS
AND COLDER AT H85 FARTHER WEST TUESDAY NIGHT INTO EARLY WEDNESDAY
MORNING. RESULT IS AT LEAST ISOLD LK EFFECT CONTINUING OVER FAR
EASTERN CWA. ECMWF MORE PROGRESSIVE WITH HEIGHTS AND KEEPS COLDER
AIR ON THE MOVE LEADING TO LESS OF CHANCE OF LK EFFECT INTO
WEDNESDAY. SOME HINT OF ANOTHER WEAKER TROUGH UPSTREAM THAT WILL
HAVE TO DROP ACROSS THE UPPER LAKES AS LARGER TROUGH MOVES TO EAST.
WILL HEDGE FORECAST TOWARD GFS/GEM-NH IDEA.
SHORTWAVE RIDGING SLIDES ACROSS AREA FOR WEDNESDAY. LINGERING LK
EFFECT CLOUDS/FLURRIES IN THE MORNING EAST...BUT THIS SHOULD BREAK
UP IN AFTN WITH ARRIVAL OF SFC-H925 RIDGE. MAY SEE INCREASING HIGH
CLOUDS OVER WEST BY LATE AFTN. OTHERWISE...A WARMER DAY SHAPING UP
WITH LIGHT WINDS/LAKE BREEZES. MIXING TO H9-H85 SUPPORTS MAX TEMPS
AS WARM AS LOWER 40S IN THE WEST AND STILL ABOVE THE FREEZING MARK
ELSEWHERE.
HIGH CLOUDS SPILLING IN LATE ON WEDNESDAY ARE IN ADVANCE OF
SHORTWAVE TROUGH TRACKING ACROSS NORTHERN MANITOBA AND NORTHERN
ONTARIO. MODELS STILL AT ODDS HOW QUICKLY THIS SYSTEM MOVES
THROUGH WEDNESDAY NIGHT AND THURSDAY. 00Z GFS WAS SLOWER BUT 06Z
LOOKS MORE LIKE ECMWF. GEM-NH WRAPPED UP AND SLOWER. HEIGHT FALLS
AND H7-H5 Q-VECTOR CONVERGENCE FOCUS MOST PRECIPITATION WELL TO
NORTH OF LK SUPERIOR. SFC-H85 FRONT/1000-850MB MOISTURE CONVERGENCE
SWINGING ACROSS LK SUPERIOR AND UPR MICHIGAN...ALONG WITH RIBBON OF
HIGHER H85-H7 MOISTURE...H85 MOISTURE/TEMPERATURE ADVECTION AND
STEEPER H7-H5 LAPSE RATES AOA 6.5C/KM NOSING IN FROM WEST ADD UP TO
BRIEF PERIOD OF SCATTERED PRECIPITATION AS FRONT WORKS THROUGH. IF
TIMING IS LIKE ECMWF...THEN BETTER CHANCES WILL BE IN THE NORTH. IF
TIMING ENDS UP SLOWER...THEN MORE AREAS SEE CHANCES AS HEATING
OF THE DAY COMBINES WITH THE FORCING. EVEN WITH SLOWER IDEA...MOST
PRECIP SHOULD BE OUT OF AREA BY MID AFTN. PTYPE ALSO DEPENDS ON
TIMING AS A LATER ARRIVAL WOULD BRING RAIN POTENTIAL INTO MIX.
FOR NOW...LOOKS LIKE MOSTLY SNOW AS SOUNDINGS INDICATE WET BULB
FALLS BLO ZERO EXCEPT FOR FAR LOWEST REACHES OF BLYR. ONCE FRONT
MOVES THROUGH QUIET WEATHER EXPECTED THROUGH FRIDAY AS HIGH PRESSURE
DRIFTS ACROSS. GFS A FEW DEGREES COLDER AT H85 ON FRIDAY COMPARED TO
ECMWF AND THUS HAS MORE IN WAY OF LAKE EFFECT CLOUDS.
SYSTEM FOR NEXT WEEKEND STILL SHOWING UP...BUT THERE REMAIN SOME
BIG QUESTIONS. UPPER LAKES REMAINS ON SOUTHERN EDGE OF STRONGER JET
STREAM RIDING ALONG SOUTHERN TIER OF CANADA...WHICH WILL HELP
ENHANCE PRECIPITATION ALONG SFC-H85 BAROCLINIC ZONE. WHERE THAT ZONE
IS LOCATED IS UNCERTAIN. AS MID-LEVEL FLOW BECOMES MORE WESTERLY...
SHORTWAVE TROUGH AND SFC-H85 LOWS MOVE FROM ROCKIES ACROSS THE
NORTHERN PLAINS INTO WESTERN GREAT LAKES. OPERATIONAL MODELS FROM
LAST NIGHT AND NAEFS ENSEMBLES INDICATED SLOWER ARRIVAL TO
PRECIPITATION NOT IMPACTING MUCH OF UPR MICHIGAN UNTIL SATURDAY
NIGHT. OF COURSE THE 12Z MODELS HAVE TRENDED QUICKER AGAIN. ECMWF IS
A LOT QUICKER...BRINGING QPF OVER MOST OF UPR MICHIGAN BY 12Z
SATURDAY...AND BASED ON 1000-500MB THICKNESS/H85 TEMPS IS SHOWING
BETTER SHOT AT MIXED PRECIPITATION. KIND OF SEEMS LIKE ECMWF IS
SHOWING TWO SEPARATE WAVES OF QPF AND THAT IS WHY IT APPEARS MUCH
FASTER WITH QPF ARRIVAL. POOR RUN-TO-RUN CONSISTENCY CONTINUES WITH
THE SYSTEM. UNTIL CONSISTENCY IMPROVES WILL KEEP WITH CONSENSUS OF
MODELS FOR THIS SYSTEM FOR POPS. ENOUGH OF A SIGNAL FROM MODELS OVER
LAST COUPLE DAYS TO GO WITH RAIN AND SNOW FOR PTYPE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 846 PM EDT SUN MAR 31 2013
WITH NOCTURNAL COOLING AND THE ARRIVAL OF SOME DEEPER
MOISTURE...EXPECT MVFR CONDITIONS WITH -SHSN TONIGHT AT ALL 3 SITES
AS THE GUSTY NW WINDS CONTINUE TO DRAW COLDER AIR INTO THE UPPER
LAKES. MAY SEE SOME VERY BRIEF PERIODS OF IFR VIS AT KIWD AND KCMX.
LAKE EFFECT SNOW SHOWERS AND MVFR CONDITIONS SHOULD PERSIST AT KIWD
AND KCMX AS UNSTABLE CONDITIONS REMAIN IN PLACE. WINDS BACKING A BIT
MORE TO THE WNW...SHOULD REDUCE CHCS FOR LAKE EFFECT SNOW SHOWERS AT
KSAW ON MONDAY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 451 PM EDT SUN MAR 31 2013
STRONG NORTH TO NORTHWEST GALES TO 45 KTS INTO EARLY THIS EVENING
AS COLD FRONT CROSSES LK SUPERIOR. STRONGEST WINDS OCCUR THROUGH
LATE EVENING IN CORRIDOR FROM CNTRL LK SUPERIOR BUOY TO STANNARD
ROCK AND ACROSS REST OF EASTERN LK SUPERIOR. GALES CONTINUE THROUGH
MONDAY AND MONDAY NIGHT OVER SAME AREAS...BUT NOT QUITE AS STRONG.
WINDS DIMINISH TO LESS THAN 25 KTS BY WEDNESDAY MORNING AS BRIEF
RIDGING MOVES ACROSS. STRONGER SOUTHWEST WINDS TO 30 KTS THEN
EXPECTED WEDNESDAY NIGHT AND THURSDAY MORNING AS LOW PRESSURE
CROSSES NORTHERN ONTARIO AND DRAGS COLD FRONT ACROSS LK SUPERIOR.
NORTHWEST WINDS TO 25 KTS DEVELOP BEHIND THE FRONT INTO NEXT
WEEKEND. THE STRONG WINDS WILL DRAW MUCH COLDER AIR INTO THE UPPER
LAKES EARLY THIS WEEK RESULTING IN FREEZING SPRAY THROUGH TUESDAY
NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND ADVISORY UNTIL 9 PM EDT THIS EVENING FOR MIZ001.
WINTER WEATHER ADVISORY UNTIL 2 PM EDT MONDAY FOR MIZ006-007-085.
LAKE SUPERIOR...
GALE WARNING UNTIL 6 AM EDT TUESDAY FOR LSZ250-251-266-267.
GALE WARNING UNTIL 6 PM EDT MONDAY FOR LSZ244-245-264-265.
GALE WARNING UNTIL 5 PM EDT MONDAY FOR LSZ249.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...VOSS
MARINE...JLA
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
723 PM EDT SUN MAR 31 2013
.AVIATION...
//DISCUSSION...
WELL MIXED WEST-NORTHWEST GRADIENT WILL PERSIST IN ADVANCE OF A COLD
FRONT THROUGH THE LATTER HALF OF THE EVENING. INTERMITTENT GUSTS
INTO THE 20 KNOT RANGE...WITH GUST FREQUENCY TENDING TO DECREASE
WITH TIME COINCIDING WITH THE LOSS OF HEATING. A LOWER STABILITY
ENVIRONMENT WILL ALLOW WIDELY SCATTERED LIGHT SHOWERS TO DEVELOP
DURING THIS TIME...BUT LIMITED COVERAGE AND DURATION WILL PRECLUDE A
MENTION. UPSTREAM RADAR DOES INDICATE A GREATER POTENTIAL FOR A
BRIEF PERIOD OF LIGHT PRECIPITATION IN MVFR ACROSS THE NORTHERN TAF
SITES AS THE FRONTAL BOUNDARY MOVES THROUGH 03-05Z. OTHERWISE...
OBSERVATIONS CONFIRM RECENT MODEL GUIDANCE IN MAINTAINING A CEILING
PREDOMINATELY WITHIN LOWER VFR THROUGH THE NIGHT...MVFR CONDITIONS
MORE WORTHY OF A TEMPO TO HIGHLIGHT THE MOST LIKELY WINDOW.
CEILINGS LIFT INTO THE 5-6K FT RANGE AS DEEPER MIXING ENSUES ON
MONDAY. GUSTY NORTHWEST WINDS FOR MONDAY AFTERNOON...PEAK GUST
POTENTIAL IN THE 25-28 KNOT RANGE.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET TONIGHT AND MONDAY
MORNING.
&&
.PREV DISCUSSION...ISSUED 339 PM EDT SUN MAR 31 2013
SHORT TERM...THROUGH TONIGHT
DEEPENING LOW PRESSURE SYSTEM OVER THE NORTHERN GREAT LAKES SENT A
WEAK TROUGH/COLD FRONTAL BOUNDARY THROUGH THE AREA THIS MORNING WITH
LITTLE IN THE WAY OF PRECIP ASSOCIATED WITH IT. IMPRESSIVE DRY SLOT
BEHIND THE TROUGH WITHIN A REGION OF DEEP MIXING HAS CLEARED OUT
MOST OF THE CLOUDS ALLOWING TEMPS TO SPIKE INTO THE MID 50S. THE
DEEP MIXING HAS ALSO PRODUCED GUSTS TO AROUND 20 KNOTS THIS
AFTERNOON. A STRONGER TROUGH/FRONT WILL GET SENT THROUGH THE REGION
THIS EVENING. MODELS INDICATE STEEP LOW LEVEL LAPSE RATES AND CAPE
VALUES BETWEEN 50-100 J/KG WITH A NARROW BAND OF THETA E JUST AHEAD
OF THE TROUGH. THEY ALSO SHOW FAIRLY LOW PWATS TIED IN THE LOW
LEVELS BRIEFLY SPIKING WITH THE THETA E AXIS BUT DRYING OUT RAPIDLY
BEHIND THE TROUGH. THE HRRR AND HIRES WRF BOTH SHOW A PERIOD OF
SHOWERS...RAIN BECOMING A MIX OF RAIN AND SNOW...BETWEEN 00Z AND 06Z
WITH POSSIBLE FLURRIES OR LIGHT SNOW SHOWERS AFTER THAT. AN AREA OF
PRECIP IS CURRENTLY SHOWING UP ON REGIONAL RADAR WITHIN THE TROUGH
SO BESIDES FINE TUNING SOME TIMING ISSUES...SEE NO REASONS TO CHANGE
MUCH WITH THE OVERNIGHT POPS/WX. WITH THE POSSIBLE CONVECTIVE NATURE
OF THE PRECIP AND LONGER DURATION...WILL LEAVE A FEW TENTHS OF SNOW
ACCUMULATIONS TO THE NORTH. WINDS WILL STAY ELEVATED OVERNIGHT WHICH
WOULD TYPICALLY LEAD TOWARD WARMER MIN TEMPS BUT CAA BEHIND THE
TROUGH WILL DROP 850MB TEMPS FROM +1C TO -11C OVERNIGHT. DEWPOINTS
UPSTREAM IN THE TEENS WILL TRY TO WORK THEIR WAY INTO THE SAGINAW
VALLEY AS WELL SO WE WILL STILL COOL OFF QUITE A BIT TONIGHT.
LONG TERM... MONDAY THROUGH NEXT SUNDAY
POLAR AIR NOW INFILTRATING THE UPPER MS VALLEY WILL BE OVER THE
GREAT LAKES REGION BY MONDAY MORNING. THIS AIRMASS IS ASSOCIATED
WITH A POLAR VORTEX NOW LOCATED OVER NRN ONTARIO. THIS UPPER LOW IS
FORECAST TO DEEPEN AS IT TRACKS NORTHEAST OF LAKE HURON AND INTO
QUEBEC ON MONDAY AND WILL REMAIN RATHER PROGRESSIVE...LIFTING INTO
NEWFOUNDLAND BY MIDWEEK. BY 12Z MON...850MB TEMPS ARE STILL FORECAST
TO PLUNGE TO -12 TO -14C OVER SE MI. WEAK MID LEVEL IMPULSES
TRACKING INTO THE REGION TUES/TUES NIGHT WILL HOLD SOME DEGREE OF
MID LEVEL TROUGHING OVER THE GREAT LAKES...WITH SE MI REMAINING
FIRMLY WITHIN THE LOW LEVEL THERMAL TROUGH. DESPITE SOME INTERVALS
OF SUN AND MIXING HEIGHTS EXTENDING UP TO 800MB...THE DEPTH OF COLD
AIR WILL REMAIN SUPPORTIVE OF DAYTIME HIGHS MON AND TUES MAINLY IN
THE 30S. NIGHTTIME MINS ARE EXPECTED TO DROP OFF INTO THE 20S
/POSSIBLY SOME TEENS IF THE BOUNDARY LAYER CAN DECOUPLE/. THESE
TEMPS ARE A GOOD 10 TO 15 DEGREES BELOW SEASONAL AVERAGES. W-NW
WINDS WILL BE QUITE GUSTY ON MONDAY AS DEEPENING SFC LOW PRESSURE
OVER QUEBEC SUSTAINS A TIGHT LOW LEVEL GRADIENT OVER THE REGION.
SOME GUSTINESS TO THE WINDS IS LIKELY TO HOLD THROUGH MUCH OF
TUESDAY AS THE LAKE AGGREGATE MAINTAINS A HEALTHY GRADIENT OVER SRN
LOWER MI. THIS WILL PUT WIND CHILL READINGS IN THE TEENS AND 20S MON
AND TUES.
THE STEEP LOW LEVEL LAPSE RATES COURTESY OF THE COLD AIR WILL ALLOW
A DIURNAL ENHANCEMENT TO THE CLOUDS MON AND TUES AFTERNOON. THE CORE
OF THE MID LEVEL COLD POOL WILL HOWEVER TRACK TO THE NORTHEAST OF
THE FORECAST AREA...THUS KEEPING CONVECTIVE CLOUD DEPTHS RATHER
SHALLOW UNDER A MID LEVEL INVERSION. THIS ALONG WITH SUBSTANTIAL LOW
LEVEL DRY AIR ADVECTION WILL SUPPORT JUST SCATTERED SNOW SHOWERS ON
MONDAY. THE 12Z MODEL SUITE DO SHOW A MID LEVEL IMPULSE /NOW LOCATED
OVER FAR NORTHERN CANADA/ DIVING INTO THE WESTERN GREAT LAKES LATE
TUES. THE CURRENT MODEL SUITE SUGGEST THIS FEATURE WILL ARRIVE INTO
SE MI TOWARD THE END OF THE DIURNAL CYCLE...WHICH SUPPORTS HOLDING
ONTO THE DRY FORECAST AT THIS TIME.
A SPLIT FLOW PATTERN IS FORECAST ACROSS NORTH AMERICA BY MID-LATE
NEXT WEEK...WITH A FAST MOVING NORTHERN STREAM WAVE EXPECTED TO
BRING A COLD FRONT INTO SRN MI IN THE THURS NIGHT/FRIDAY TIME FRAME.
STEADY WARM AIR ADVECTION WILL ALLOW TEMPS TO RISE BACK UP INTO THE
50S ON THURSDAY PRIOR TO THE COLD FRONT PASSAGE. WHILE THE MEDIUM
RANGE MODEL SUITE ARE IN GOOD AGREEMENT IN SHOWING A STRONG LOWER
TROPOSPHERIC BAROCLINIC ZONE SETTING UP ACROSS THE NRN PLAINS AND
GREAT LAKES REGION BY NEXT WEEKEND...THERE IS CONSIDERABLE
DIFFERENCES WITH RESPECT TO THE TIMING AND AMPLITUDE OF MID LEVEL
SHORT WAVE ENERGY EMANATING FROM THE PACIFIC AND TRACKING ALONG THE
BAROCLINIC ZONE. LARGE SPREAD AMONG ENSEMBLE MEMBERS ADDS TO THE
UNCERTAINTY. THERE IS HOWEVER ENOUGH CONFIDENCE TO CARRY A CHANCE OF
PRECIP NEXT WEEKEND.
MARINE...
DEEPENING LOW PRESSURE SYSTEM OVER THE NORTHERN GREAT LAKES WILL
DROP THE SECOND OF TWO SURFACE TROUGHS THROUGH THE GREAT LAKES THIS
EVENING...USHERING A MUCH COLDER AIRMASS INTO THE REGION. STRONG
WESTERLY WINDS WILL VEER TO THE NORTHWEST BEHIND THIS TROUGH AND
INCREASE WITH A TIGHTENING PRESSURE GRADIENT...ESPECIALLY OVER THE
NORTHERN HALF OF LAKE HURON OVERNIGHT. A GALE WARNING HAS BEEN
ISSUED FOR THE OPEN WATERS OF NORTHERN LAKE HURON WITH SMALL CRAFT
ADVISORIES FOR ALL NEARSHORE WATERS OF LAKE HURON. WINDS WILL REMAIN
ELEVATED THROUGH MONDAY NIGHT.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
GALE WARNING...LHZ361-LHZ362-LHZ363-LHZ462...UNTIL 10 PM MONDAY.
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS
FROM PORT AUSTIN TO HARBOR BEACH...UNTIL 8 AM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO PORT
HURON...FROM 4 AM MONDAY TO 8 AM TUESDAY.
SMALL CRAFT ADVISORY...INNER SAGINAW BAY...FROM 4 AM MONDAY TO 10
PM MONDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....MR
SHORT TERM...DRK
LONG TERM....SC
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
458 PM EDT SAT MAR 30 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 453 PM EDT SAT MAR 30 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A RIDGE OVER THE FAR WRN
CONUS INTO WRN CANADA WHILE DOWNSTREAM TROF WAS AMPLIFYING S THRU
CNTRL CANADA INTO THE NCNTRL CONUS. WITHIN THE DEEPENING TROF...A
SHORTWAVE MOVING ACROSS THE UPPER GREAT LAKES HAS BROUGHT A BAND OF
PCPN TO UPPER MI TODAY. PCPN WAS MAINLY RAIN OVER THE W...BUT MIXED
WITH/CHANGED TO SNOW OVER THE CNTRL/E. SNOW WAS MDT/HVY ACROSS
IRON/DICKINSON COUNTIES WHERE A FEW INCHES OF WET SNOW ACCUMULATION
HAS BEEN REPORTED. THE HEAVIER SNOW IS NOW STREAKING E TOWARD LUCE
COUNTY. BACKEDGE OF THE MAIN PCPN AREA WAS OVER CNTRL UPPER MI AS OF
20Z. WITH DEPARTURE OF THIS AREA OF PCPN...ATTENTION IN THE SHORT
TERM SHIFTS TO SHORTWAVE DIGGING SHARPLY INTO THE UPPER GREAT LAKES
LATE TONIGHT/SUN AND THE INCREASINGLY COLDER AIR IT WILL BRING.
INCORPORATING EXTRAPOLATION FOR ENDING PCPN...EXPECT STEADIER PCPN
TO EXIT THE ERN FCST AREA AROUND 03Z WITH ALL OF THE AREA DRY BY
06Z. MAY SEE AN INCH OR SO OF WET SNOW OVER THE INTERIOR E DURING
THE LATE AFTN. LOW CLOUDS AND FOG WERE PRESENT EARLY TODAY BEHIND
THE PCPN AREA IN MN...AND WILL PROBABLY SEE SOME OF THAT AND PERHAPS
SOME -DZ IN MAINLY AREAS THAT SEE UPSLOPING WITH A W WIND FOR A FEW
HRS AFTER PCPN ENDS AND BEFORE THE ONSET OF CAA OVERNIGHT INCREASES
LOW-LEVEL MIXING. BY 12Z...850MB TEMPS ARE PROGGED AT -8/-9C OVER
WRN LAKE SUPERIOR. WHILE THAT IS SHY OF THE THRESHOLD FOR LES GIVEN
WATER TEMPS AROUND 1C...SRN EDGE OF DEEP LAYER FORCING ASSOCIATED
WITH APPROACHING SHORTWAVE AND PRESENCE OF CYCLONIC FLOW MAY
GENERATE SOME LAKE ENHANCED -SHSN OVER NW UPPER MI LATE IN THE
NIGHT.
DURING THE DAY SUN...SHORTWAVE DIGS S ACROSS THE UPPER GREAT
LAKES...BRINGING 100-120M HEIGHT FALLS AT 500MB. ALTHOUGH BEST DEEP
LAYER FORCING PASSES N AND NE OF UPPER MI...DEEP CYCLONIC FLOW AND
SUFFICIENT INCREASE IN MOISTURE DEPTH TO AROUND 10KFT SUGGESTS SCT
TO NMRS -SHSN ARE A GOOD BET. LATE MAR SOLAR INSOLATION WILL ADD A
DIURNAL COMPONENT TO -SHSN COVERAGE OVER THE INTERIOR WHILE
DISRUPTING NORMAL LAKE EFFECT PROCESSES THAT WOULD BE GETTING
UNDERWAY OVER LAKE SUPERIOR AS 850MB TEMPS FALL TOWARD -14C IN THE
AFTN. ALTHOUGH COLUMN BECOMES MORE SUPPORTIVE OF SNOW AS PTYPE AS
THE DAY PROGRESSES...DAYTIME HEATING SHOULD RESULT IN MIX WITH -SHRA
INTO THE MID AFTN OVER THE SCNTRL. WINDS MAY APPROACH ADVY CRITERIA
OVER THE KEWEENAW...BUT WITH MIXED LAYER WINDS LOW/MID 30KT AT MOST
AND ONLY MODEST PRES RISES APPROACHING FROM THE NW...DO NOT
ANTICIPATE WIND ADVY BEING NEEDED AT THIS POINT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 453 PM EDT SAT MAR 30 2013
CONTINUE TO SEE GOOD AGREEMENT FROM GFS/ECMWF/GEM-NH IN OVERALL
LARGER SCALE PATTERN FOR THE LONG TERM. DEEP AND COLD TROUGHING
INITIALLY IN PLACE LEADS TO A PERIOD OF LAKE ENHANCED SNOW FOR
SNOWBELTS FAVORED BY NORTHWEST WINDS SUNDAY NIGHT THROUGH TUESDAY
MORNING. FOCUSED IN ON MORE OF THE DETAILS THIS GO AROUND. WAVE
THAT MOVES THROUGH TO BRING IN THE TROUGHING ON SUNDAY NIGHT PRETTY
SHARP UPSTREAM THIS MORNING OVER NORTHERN MANITOBA INTO NINAVUT.
WENT WITH MODELS THAT WERE SHARPER WITH H5 WAVE AND RESULTING SFC
TROUGH DROPPING ACROSS LK SUPERIOR LATE SUNDAY AFTN INTO SUNDAY
EVENING. SOUNDINGS DURING THAT TIME INDICATE MORE OF A WIDESPREAD
SNOW JUST IN WAKE OF FRONT...ALONG WITH PUSH OF NORTH WINDS TO AROUND
40 MPH. EXPANDED POPS OVER MUCH OF THE NORTH HALF OF CWA SUNDAY
EVENING. SNOWFALL RATES MAY EXCEED 1"/HOUR FOR A COUPLE HOURS AS
THIS BAND OF SNOW MOVES THROUGH. BY MIDNIGHT...MODELS INDICATE
WIDESPREAD DEEPER H8-H7 MOISTURE DEPARTS LEAVING MOST OF THE SNOW
SET UP OVER HIGHER TERRAIN OF WEST AND NCNTRL CWA AND ALSO FOR
SNOWBELTS FROM MUNISING TO NEWBERRY.
LAKE ENHANCED SNOW THAT OCCURS FOR THOSE SNOWBELTS LATER SUNDAY
NIGHT INTO MONDAY MAY BE HEAVY AT TIMES AS SOUNDINGS INDICATE
MOISTURE THROUGH H8 AND INVERSION HEIGHTS UP TO 10KFT. OVER-WATER
INSTABILITY IS SUFFICIENT AS H85 TEMPS ARE AROUND -16C. AT FIRST
GLANCE SEEMS LIKE LAKE EFFECT SNOW WATCH MAY BE IN ORDER. THERE ARE
A COUPLE NEGATIVE FACTORS THOUGH THAT PROHIBITED ISSUANCE OF WATCH.
FIRST OF WHICH IS DRYING NOTED BLO 5KFT LEADING TO MORE OF AN
INVERTED-V LOOK TO SOUNDING...ESPECIALLY OVERNIGHT SUNDAY NIGHT INTO
MONDAY. SECOND NEGATIVE IS SHEAR IN THE MOIST CONVECTIVE LAYER AT
LEAST TO START OUT...BUT THIS DOES EASE LATE SUNDAY NIGHT THOUGH BLYR
WINDS STAY UP TO 30 KTS FROM THE NORTHWEST. BEST SHOT AT HEAVIER SNOW
WOULD BE THROUGH MID-LATE MORNING ON MONDAY AS DAYTIME HEATING/HIGHER
SUN ANGLE WILL ACT TO DISRUPT SNOW SHOWERS AS THE DAY GOES ON. LAKE
EFFECT SNOW SHOWERS MAY INCREASE AGAIN MONDAY NIGHT. DUE TO COMBO OF
THE LAKE EFFECT SNOWS AND BLOWING SNOW...LIKELY WILL NEED ADVISORY
HEADLINES INTO MONDAY NIGHT AND TUESDAY MORNING.
SINCE THERE IS NOT MUCH BLOCKINESS DOWNSTREAM...DEEP TROUGH WILL REMAIN
PROGRESSIVE WITH RISING HEIGHTS DEVELOPING OVER UPPER LAKES AS EARLY
AS TUESDAY. SUFFICIENTLY COLD AND MOIST ENOUGH FOR LK EFFECT BUT
LARGER SCALE NEGATIVES SHOULD RESULT IN DIMINISHING TREND TO LK
EFFECT BY TUESDAY AFTN. POPS REFLECTED THIS FOR MOST PART...JUST
NEEDED SOME MINOR TWEAKS.
AFTER PARTIAL CLEARING AND WARMER CONDITIONS FOR WEDNESDAY ANOTHER
SHORTWAVE TROUGH THEN SWINGS ACROSS MANITOBA AND NORTHERN ONTARIO
WEDNESDAY NIGHT AND THURSDAY. ASSOCIATED COLD FRONT MOVES ACROSS
UPPER LAKES ON THURSDAY. DPROG/DT FROM EARLIER GFS/ECMWF RUNS
INDICATED A SLOWER TREND WITH SHORTWAVE POINTING TO MOST OF
PRECIPITATION FROM THE SYSTEM TAKING PLACE ON THURSDAY OVER UPPER
MICHIGAN. 12Z GFS REALLY SPED UP AND SEEMS OUT OF PLACE NOW WITH
PCPN TIMING. 1000-500MB AND 1000-850MB THICKNESSES INDICATE MIX OF
RAIN/SNOW. LIMITED MOISTURE WILL KEEP AMOUNTS LIGHT. COOLER AND DRY
IN WAKE OF COLD FRONT INTO FRIDAY.
QUESTIONS INCREASE FOR NEXT WEEKEND. GOOD BET THAT UPPER LAKES WILL
BE ON THE SOUTHERN EDGE OF STRONGER JET STREAM RIDING ALONG SOUTHERN
TIER OF CANADA. AS MID-LEVEL FLOW BECOMES MORE WESTERLY MODELS
INDICATE SHORTWAVE TROUGH AND SFC-H85 LOWS VCNTY OF NORTHERN PLAINS
INTO WESTERN GREAT LAKES BY 12Z SATURDAY. POOR CONSISTENCY ON WHERE
SFC-H85 LOWS SET UP THOUGH. LATEST ECMWF/GFS CONTINUE TO INDICATE
FARTHER NORTH LOW WITH QPF INTO UPPER LAKES BY NEXT SATURDAY WHILE
EARLIER RUNS KEPT MOST OF QPF TO SOUTH. 1000-500MB AND 1000-850MB
THICKNESSES AT OR ABOVE 540DAM AND 1305M AND H85 TEMPS OVER 0C INTO
WESTERN CWA INDICATE MIX OF RAIN AND SNOW. CONSENSUS OF MODELS CAME
UP WITH HIGHER CHANCE POPS WHICH WILL WORK IF THE NORTHERN TREND
CONTINUES IN THE MODELS. JUST CANNOT SEEM TO SHAKE THIS COOLER AND
ACTIVE WEATHER PATTERN AS WE HEAD INTO THE FIRST WEEK OF APRIL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 134 PM EDT SAT MAR 30 2013
AREA OF PCPN ASSOCIATED WITH LOW PRES TROF HAS SHIFTED E OF KIWD AND
WILL SOON BE E OF KCMX. PER SATELLITE IMAGERY AND PER SFC OBS
SHOWING INCREASING SFC T/TD SPREADS UPSTREAM...THERE SHOULD BE
SUFFICIENT DRYING BEHIND TROF TO ALLOW IFR CONDITIONS TO IMPROVE TO
MVFR AND THEN VFR AT KIWD BY LATE AFTN. MEANWHILE...AT KCMX...EXPECT
IFR/LIFR CONDITIONS TO IMPROVE TO MVFR LATE IN THE AFTN. APPROACH OF
NEXT DISTURBANCE WILL BRING A RETURN TO MVFR CONDITIONS AT KIWD
OVERNIGHT. EXPECT INCREASING POTENTIAL OF -SHSN AND CONTINUED MVFR
AT KIWD/KCMX LATE TONIGHT/SUN MORNING AS DISTURBANCE ARRIVES. GUSTY
WNW WINDS WILL DEVELOP FOLLOWING NEXT SFC TROF PASSAGE LATE MORNING.
AT KSAW...IFR/LIFR CONDITIONS WITH -SN/-RA SHOULD IMPROVE TO MVFR
LATE AFTN AS PCPN EXITS. DRYING IS MORE UNCERTAIN AT KSAW DUE TO
LIGHTER WIND REGIME AND LESS POTENTIAL TO ADVECT DRIER AIR INTO THE
AREA. ALTHOUGH WESTERLY WIND WOULD FAVOR DOWNSLOPE DRYING...OPTED TO
MAINTAIN MVFR THRU THE EVENING AS WINDS ARE LIGHT. AS WINDS DIMINISH
FURTHER OVERNIGHT...MAY SEE IFR CIGS DEVELOP. EXPECT IMPROVEMENT TO
MVFR IN THE MORNING UNDER STRENGTHENING CAA.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 453 PM EDT SAT MAR 30 2013
STRONGER DISTURBANCE MOVING INTO THE UPPER LAKES SUN WILL USHER
COLDER AIR OVER LAKE SUPERIOR WHILE SFC LOW PRES DEEPENS TO THE E
AND NE. THIS WILL RESULT IN STRENGTHENING NW WINDS ACROSS THE LAKE.
IN FACT...NW GALES ARE EXPECTED TO DEVELOP OVER CNTRL AND ERN LAKE
SUPERIOR SUN AFTN. UNDER SLOW MOVING WEATHER PATTERN WITH COLD
UNSTABLE AIR OVER THE LAKE...THE GALES WILL LIKELY CONTINUE INTO
TUE. FREEZING SPRAY WILL ALSO DEVELOP SUN NIGHT AND LINGER INTO TUE
AS UNSEASONABLY COLD AIR SETTLES OVER THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 2 PM SUNDAY TO 8 PM EDT TUESDAY FOR LSZ264>267.
GALE WARNING FROM 2 PM SUNDAY TO 6 PM EDT MONDAY FOR LSZ244-245-
249>251.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
909 PM CDT SUN MAR 31 2013
.UPDATE...THE FORECAST HAS BEEN UPDATED TO REMOVE POPS FOR THE
SOUTHEASTERN CWA FOR THE REMAINDER OF THE NIGHT...AS SHWRS AND TSTMS
HAVE MOVED EAST OF THE FORECAST AREA. HOURLY TEMPERATURES WERE ALSO
SLIGHTLY TWEAKED TO ACCOUNT FOR THE LATEST TRENDS. AREAS OF LOW
CLOUDS AND FOG WILL REDEVELOP THIS EVENING WITH AREAS OF DENSE FOG
POSSIBLE THROUGH EARLY MONDAY MORNING. /27/
&&
.AVIATION...AREAS OF IFR/MVFR CLOUDS DECKS WILL CONTINUE THIS
EVENING WITH PATCHES OF IFR/LIFR CIG/VSBY IN FOG. LOW CLOUDS AND FOG
WILL BE ON THE INCREASE LATER TONIGHT BECOMING WIDESPREAD AFTER
MIDNIGHT. FOG WILL CLEAR AND LOW CLOUDS WILL LIFT 13-15Z MONDAY
FOR VFR CONDITIONS BY MID MORNING.
&&
PREV DISCUSSION...
TODAY THROUGH EARLY WEDNESDAY
WEAKENING SQUALL LINE PUSHING THROUGH THE REGION TO THE SOUTHEAST
TONIGHT WITH QUIETER WEATHER MONDAY AND TUESDAY BEFORE MORE RAIN FOR
MIDDLE TO LATE WEEK.
SEVERAL REPORTS OF TREES AND POWERLINES DOWN HAVE COME IN FROM
NORTHEAST LA AND WEST MS AS THE ONCE STRONGER SQUALL LINE MOVED
THROUGH. HOWEVER, AN OVERALL WEAKENING TREND OVER THE PAST HOUR AS
BEEN OBSERVED AS IT ENCOUNTERS A LESS FAVORABLE AIRMASS TO THE EAST.
WARMING CLOUD TOPS VIA IR SAT AND WEAKENING REFLECTIVITY GRADIENT
FURTHER SUGGEST MCS IS BECOMING COLD POOL DOMINATED WHILE BEING
FARTHER REMOVED FROM LARGER SCALE FORCING. HAVE CANCELED PORTIONS OF
THE SEVERE TSTORM WATCH TO THE WEST OF THE CURRENT LINE. THE BEST
ENVIRONMENT FOR MARGINAL STRONG TO BRIEFLY SEVERE STORMS IS ACROSS
FAR S/SE AREAS WHERE RAP OUTPUT SUGGEST 500-1000 J/KG SBCAPE AND ~30
KT ORGANIZATIONAL DEEP LAYER SHEAR. HOWEVER, FEEL THE COLD POOL
DOMINATION AND LACK OF FORCING SHOULD KEEP MOST STORMS IN CHECK FROM
BEING SEVERE ACROSS THE REMAINDER OF THE AREA. BUT ONE OR TWO STORMS
COULD BRIEFLY BECOME SEVERE ACROSS THIS AREA TROUGH EARLY EVENING.
AS THE TSTORM LINE AND CLOUDS CLEAR TONIGHT FROM THE NORTH,
DEVELOPMENT OF FOG WILL BE LIKELY ACROSS A MAJORITY OF THE REGION.
SOME ISOLATED LOCATIONS OF DENSE FOG ARE PSBL TONIGHT THROUGH 8AM
TOMORROW MRNG. FOG WILL DISSIPATE THROUGH 9AM AS MIXING STEADILY
INCREASES.
THE WEAKENING TSTORM LINE WAS INITIATED ON A LOW-LVL FRONTAL
BOUNDARY AND A NRN STREAM H5 S/WV TROUGH PIVOTING ACROSS THE LOWER
PLAINS. THIS FRONTAL BOUNDARY WILL STALL ALONG THE I-10 TO HIGHWAY
84 CORRIDOR SECTOR OVERNIGHT AND MONDAY. ANOTHER QUICK MOVING
IMPULSE IN THE NW FLOW MAY HELP SOME SHOWERS LINGER THROUGH THE
EARLY MRNG HOURS ACROSS FAR SOUTHERN LOCATIONS. THIS BOUNDARY WILL
SERVE AS A IMPETUS FOR A FEW SHOWERS AND THUNDERSTORMS MON AFTN ALSO
AS DIURNALLY DRIVEN INSTABILITY BUILDS INVOF GREATEST SFC
CONVERGENCE. MAV POPS CAME IN QUITE LOW DESPITE GFS HOLDING UP THE
FRONT ACROSS THIS REGION. THE EC AND NAM ARE IN AGREEMENT OF
DIURNALLY DRIVEN QPF ALSO. THEREFORE, BUMPED POPS UP ACROSS SRN TIER
OVER MAV. FOR CNTRL AND NORTH AREAS HOWEVER, BUFR SOUNDINGS SUGGEST
AMPLE SUN WITH TEMPS RISING INTO THE MID 70S AS SFC HIGH PRESSURE
AXIS NOSES IN.
THE SFC HIGH PRESSURE WILL ALSO AID IN A REINFORCING SHOT OF
COOLER/DRIER AIR IN THE LOW LEVELS TUESDAY MRNG THAT WILL QUELL
TEMPS FROM REACHING MONDAY`S LEVELS. MID AND HIGH LEVEL CLOUDS WILL
BE ON THE INCREASE TUESDAY INTO TUESDAY NIGHT AS OUR NEXT SYSTEM
TAKES SHAPE ACROSS THE INTER-MOUNTAIN WEST. A SUPPRESSED PACIFIC H5
S/WV TROUGH WILL SWING ACROSS THE FOUR CORNERS REGION LATE TUESDAY
AND HELP SFC LOW CYCLOGENESIS ACROSS TEXAS. A DECENT PRESSURE
GRADIENT APPEARS TO BE IN PLACE GOING INTO TUES NIGHT WITH SFC HIGH
JUST OFF TO NORTH AND THE DEVELOPING SFC LOW. SMALL PERTURBATIONS/
IMPULSES IN THE H5 FLOW WILL MOVE OVER TOP THE ARKLAMISS LATE TUES
INTO EARLY WEDS AIDING IN ISENTROPIC ASCENT. LIGHT SHOWER ACTIVITY
WILL BE ON THE INCREASE LATE TUES NIGHT INTO WED MRNG FOR WESTERN
AND CENTRAL ARKLAMISS AREAS.
FOR FORECAST ELEMENTS...WINDS WERE BUMPED UP IN ASSOCIATION WITH THE
TSTORM COMPLEX. MAV POPS WERE BUMPED DOWN DRAMATICALLY TONIGHT THEN
SLIGHTLY UP FOR SOUTHERN AREAS DAY PERIOD MONDAY. FOG WAS ADDED TO
THE OVRNGT PERIOD ALSO. MAV POPS WERE GENERALLY FOLLOWED TUESDAY
NIGHT INTO WEDNESDAY. MAV TEMPS WERE DROPPED A TOUCH FOR NRN AREAS
TOMORROW GIVEN BUFR SOUNDINGS AND MAX HEATING POTENTIAL. /ALLEN/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 54 78 49 69 / 10 14 4 20
MERIDIAN 53 77 45 72 / 14 13 4 12
VICKSBURG 54 78 51 68 / 9 14 3 31
HATTIESBURG 60 79 51 74 / 14 22 5 13
NATCHEZ 54 77 54 70 / 10 20 3 28
GREENVILLE 52 75 46 61 / 7 10 3 36
GREENWOOD 51 75 46 65 / 9 10 4 26
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
27/ALLEN
AREA FORECAST DISCUSSION
NWS JACKSON MS
755 PM CDT SUN MAR 31 2013
.UPDATE...THE FORECAST HAS BEEN UPDATED TO REMOVE SEVERE POTENTIAL
FOR THE AREA. THE WATCH HAS BEEN CANCELLED AND THE TSTMS HAVE MOVED
TO THE EAST OF THE FORECAST AREA. POPS AND CLOUD COVER WAS ALSO
ADJUSTED IN THE WAKE OF THE BAND OF STORMS AND TEMPERATURES WERE
TWEAKED SLIGHTLY COOLER DUE TO CLEARING SKIES IN THE IMMEDIATE WAKE
OF THE RAINFALL. AREAS OF LOW CLOUDS AND FOG WILL REDEVELOP AFTER
DARK WITH PATCHES OF DENSE FOG POSSIBLE THROUGH EARLY MONDAY MORNING.
&&
.PREV DISCUSSION...
TODAY THROUGH EARLY WEDNESDAY
WEAKENING SQUALL LINE PUSHING THROUGH THE REGION TO THE SOUTHEAST
TONIGHT WITH QUIETER WEATHER MONDAY AND TUESDAY BEFORE MORE RAIN FOR
MIDDLE TO LATE WEEK.
SEVERAL REPORTS OF TREES AND POWERLINES DOWN HAVE COME IN FROM
NORTHEAST LA AND WEST MS AS THE ONCE STRONGER SQUALL LINE MOVED
THROUGH. HOWEVER, AN OVERALL WEAKENING TREND OVER THE PAST HOUR AS
BEEN OBSERVED AS IT ENCOUNTERS A LESS FAVORABLE AIRMASS TO THE EAST.
WARMING CLOUD TOPS VIA IR SAT AND WEAKENING REFLECTIVITY GRADIENT
FURTHER SUGGEST MCS IS BECOMING COLD POOL DOMINATED WHILE BEING
FARTHER REMOVED FROM LARGER SCALE FORCING. HAVE CANCELED PORTIONS OF
THE SEVERE TSTORM WATCH TO THE WEST OF THE CURRENT LINE. THE BEST
ENVIRONMENT FOR MARGINAL STRONG TO BRIEFLY SEVERE STORMS IS ACROSS
FAR S/SE AREAS WHERE RAP OUTPUT SUGGEST 500-1000 J/KG SBCAPE AND ~30
KT ORGANIZATIONAL DEEP LAYER SHEAR. HOWEVER, FEEL THE COLD POOL
DOMINATION AND LACK OF FORCING SHOULD KEEP MOST STORMS IN CHECK FROM
BEING SEVERE ACROSS THE REMAINDER OF THE AREA. BUT ONE OR TWO STORMS
COULD BRIEFLY BECOME SEVERE ACROSS THIS AREA TROUGH EARLY EVENING.
AS THE TSTORM LINE AND CLOUDS CLEAR TONIGHT FROM THE NORTH,
DEVELOPMENT OF FOG WILL BE LIKELY ACROSS A MAJORITY OF THE REGION.
SOME ISOLATED LOCATIONS OF DENSE FOG ARE PSBL TONIGHT THROUGH 8AM
TOMORROW MRNG. FOG WILL DISSIPATE THROUGH 9AM AS MIXING STEADILY
INCREASES.
THE WEAKENING TSTORM LINE WAS INITIATED ON A LOW-LVL FRONTAL
BOUNDARY AND A NRN STREAM H5 S/WV TROUGH PIVOTING ACROSS THE LOWER
PLAINS. THIS FRONTAL BOUNDARY WILL STALL ALONG THE I-10 TO HIGHWAY
84 CORRIDOR SECTOR OVERNIGHT AND MONDAY. ANOTHER QUICK MOVING
IMPULSE IN THE NW FLOW MAY HELP SOME SHOWERS LINGER THROUGH THE
EARLY MRNG HOURS ACROSS FAR SOUTHERN LOCATIONS. THIS BOUNDARY WILL
SERVE AS A IMPETUS FOR A FEW SHOWERS AND THUNDERSTORMS MON AFTN ALSO
AS DIURNALLY DRIVEN INSTABILITY BUILDS INVOF GREATEST SFC
CONVERGENCE. MAV POPS CAME IN QUITE LOW DESPITE GFS HOLDING UP THE
FRONT ACROSS THIS REGION. THE EC AND NAM ARE IN AGREEMENT OF
DIURNALLY DRIVEN QPF ALSO. THEREFORE, BUMPED POPS UP ACROSS SRN TIER
OVER MAV. FOR CNTRL AND NORTH AREAS HOWEVER, BUFR SOUNDINGS SUGGEST
AMPLE SUN WITH TEMPS RISING INTO THE MID 70S AS SFC HIGH PRESSURE
AXIS NOSES IN.
THE SFC HIGH PRESSURE WILL ALSO AID IN A REINFORCING SHOT OF
COOLER/DRIER AIR IN THE LOW LEVELS TUESDAY MRNG THAT WILL QUELL
TEMPS FROM REACHING MONDAY`S LEVELS. MID AND HIGH LEVEL CLOUDS WILL
BE ON THE INCREASE TUESDAY INTO TUESDAY NIGHT AS OUR NEXT SYSTEM
TAKES SHAPE ACROSS THE INTER-MOUNTAIN WEST. A SUPPRESSED PACIFIC H5
S/WV TROUGH WILL SWING ACROSS THE FOUR CORNERS REGION LATE TUESDAY
AND HELP SFC LOW CYCLOGENESIS ACROSS TEXAS. A DECENT PRESSURE
GRADIENT APPEARS TO BE IN PLACE GOING INTO TUES NIGHT WITH SFC HIGH
JUST OFF TO NORTH AND THE DEVELOPING SFC LOW. SMALL PERTURBATIONS/
IMPULSES IN THE H5 FLOW WILL MOVE OVER TOP THE ARKLAMISS LATE TUES
INTO EARLY WEDS AIDING IN ISENTROPIC ASCENT. LIGHT SHOWER ACTIVITY
WILL BE ON THE INCREASE LATE TUES NIGHT INTO WED MRNG FOR WESTERN
AND CENTRAL ARKLAMISS AREAS.
FOR FORECAST ELEMENTS...WINDS WERE BUMPED UP IN ASSOCIATION WITH THE
TSTORM COMPLEX. MAV POPS WERE BUMPED DOWN DRAMATICALLY TONIGHT THEN
SLIGHTLY UP FOR SOUTHERN AREAS DAY PERIOD MONDAY. FOG WAS ADDED TO
THE OVRNGT PERIOD ALSO. MAV POPS WERE GENERALLY FOLLOWED TUESDAY
NIGHT INTO WEDNESDAY. MAV TEMPS WERE DROPPED A TOUCH FOR NRN AREAS
TOMORROW GIVEN BUFR SOUNDINGS AND MAX HEATING POTENTIAL. /ALLEN/
&&
.AVIATION...AREAS OF IFR/MVFR CLOUDS DECKS WILL CONTINUE THIS
EVENING WITH ISOLATED LIGHT SHOWERS OVER ERN ZONES THROUGH 9 PM.
CLOUDS WILL BE ON THE INCREASE LATER TONIGHT WITH WIDESPREAD IFR
CIGS AND PATCHES OF IFR/LIFR VSBYS DUE IN FOG. FOG WILL CLEAR AND
LOW CLOUDS WILL LIFTS BY 14Z MONDAY FOR VFR CONDITIONS BY LATE
MORNING.
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
ALLEN/15/03
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1213 PM CDT SAT MAR 30 2013
.UPDATE...
ISSUED AT 1212 PM CDT SAT MAR 30 2013
STRATUS CONTS TO MIX OUT. ONLY THE FAR SE FRINGE OF THE FCST AREA
HAS ANY STRATUS OVC BUT IT IS RAPIDLY THINNING/DISSIPATING. FCST
TEMPS WERE RUNNING TOO WARM WHERE STRATUS HAS IMPEDED WARMING. SO
MERGED CURRENT OBS WITH THE FCST 3 HRS IN ADVANCE TO GET BACK ON
THE TEMP CURVE. DWPTS CONT MUCH HIGHER THAN FCST. SO USED HRRR FOR
18Z AND NAM FOR 21Z/00Z AND INTERPOLATED WITH CURRENT OBS.
THE STRATUS WILL CLEAR RESULTING IN A RAPID INCREASE IN TEMPS. GRI
IS ALREADY 60F. SO WE MAY NEED TO INCREASE HIGH TEMPS. THE FIRST
BATCH OF MID-LEVEL SHWRS WILL BE MOVING INTO VALLEY/GREELEY
COUNTIES WITHIN THE HR. AT THIS POINT BELIEVE THE SUB-CLOUD LAYER
IS TOO DRY FOR SPRINKLES. CLOUD BASES ARE AVERAGING AROUND 10K FT.
THE 4 AM FCST EMPHASIZES SHWR CHANCES OVER THE WRN FRINGE OF THE
FCST AREA THIS AFTN. BASED ON CURRENT SATL WE MADE NEED TO
RECONFIGURE THEM MORE ACROSS OUR NRN COUNTIES.
UPDATE ISSUED AT 915 AM CDT SAT MAR 30 2013
ESTF UPDATE EXTENDED THE DENSE FOG ADVY THRU 16Z BUT WE WERE ABLE
TO REMOVE SOME COUNTIES. VIS SATL SHOWS STRATUS/FOG IS SHIFTING S.
IT/S THIN AND SUN WARMING THE GROUND AROUND ITS EDGES...EXPECT
MIXING WILL DISSIPATE THE FOG/STRATUS BY NO LATER THAN 18Z.
SOME ADJUSTMENTS TO SHORT-TERM CLOUDS WERE ALSO MADE. WE MAY NEED
TO ADJUST TEMP CURVES AS STRATUS WILL HAMPER HEATING OVER THE NEXT
COUPLE HRS.
PLEASE SEE UPDATED AVN SECTION.
UPDATE ISSUED AT 650 AM CDT SAT MAR 30 2013
AS MENTIONED IN THE SHORT-TERM DISCUSSION BELOW...REMNANT MOISTURE
FROM LAST NIGHTS RAIN HAS PROVIDED HIGH DEWPOINTS AND WITH THE
LOWER TROPOSPHERE READILY RADIATING OUT...NEAR-ZERO TO ZERO LOW
LEVEL DEWPOINT DEPRESSIONS HAVE RESULTED ACROSS MUCH OF THE CWA.
IN ADDITION...AS OF 11Z THE SURFACE TROUGH WAS NOTED BISECTING THE
CWA FROM NORTHEAST TO SOUTHWEST. THE LOW LEVEL WIND FIELD ACROSS
OUR CWA HAS BECOME VERY LIGHT AS A RESULT. THE COMBINATION OF LOW
DEWPOINT DEPRESSIONS AND A LIGHT WIND HAS RESULTED IN WIDESPREAD
FOG DEVELOPMENT ACROSS THE CWA...WITH MANY LOCATIONS NEAR OR BELOW
1/4SM. THIS FOG SHOULD DIMINISH RAPIDLY POST SUNRISE AS DIABATIC
HEATING COMMENCES THUS PROVIDING INCREASING BOUNDARY LAYER HEIGHT
AND MIXING. UNTIL THAT TIME HOWEVER...DENSE FOG WILL PERSIST
ACROSS MUCH OF THE AREA AND AS A RESULT...WENT AHEAD WITH A DENSE
FOG ADVISORY...IN EFFECT UNTIL 14Z...FOR LOCATIONS GENERALLY ALONG
AND NORTHWEST OF A LINE FROM OSBORNE TO OSCEOLA. REMAINDER OF THE
FORECAST REMAINS IN GOOD SHAPE WITH ONLY MINOR TWEAKS MADE TO
HOURLY TEMPERATURE...DEWPOINT AND WIND GRIDS TO BETTER REFLECT
CURRENT CONDITIONS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 441 AM CDT SAT MAR 30 2013
OVERNIGHT UPPER AIR ANALYSIS INDICATES NORTHWESTERLY MID AND UPPER
LEVEL FLOW OVER THE WESTERN HALF OF THE CONUS...WITH QUASI-ZONAL
FLOW PERSISTING ACROSS THE EAST. MID AND UPPER LEVEL FLOW OVER OUR
AREA MAXES OUT AT AROUND 55KTS NEAR 200MB PER 00Z SOUNDING DATA
FROM KOAX. WATER VAPOR IMAGERY INDICATES A MID LEVEL PERTURBATION
MOVING OVER THE CENTRAL PLAINS...WITH ANOTHER MID LEVEL
PERTURBATION OVER THE NORTHERN PLAINS. AT THE SURFACE A TROUGH OF
LOW BAROMETRIC PRESSURE EXISTS FROM EASTERN SOUTH DAKOTA INTO
WESTERN NEBRASKA AND WESTERN KANSAS. THE SYNOPTIC LOW LEVEL WIND
FIELD REMAINS FROM THE SOUTHEAST ACROSS OUR CWA AS A
RESULT...ALTHOUGH REMNANT OUTFLOW FROM EARLIER CONVECTION HAS
DISRUPTED THE SYNOPTIC FLOW AT A FEW LOCATIONS ACROSS OUR CWA.
RADAR DATA FROM KUEX INDICATES LINGERING CONVECTION OVER EASTERN
NEBRASKA...WITH SOME OF THIS ACTIVITY STILL IMPACTING EXTREME
EASTERN PORTIONS OF OUR CWA. REGIONAL RADAR DATA ALSO INDICATES
ADDITIONAL CONVECTION ONGOING ACROSS PORTIONS OF CENTRAL AND
EASTERN KANSAS. CLOUDY SKIES PERSIST OVER EAST/SOUTHEASTERN
PORTIONS OF OUR CWA WHERE CONVECTION IS NEAR AND ALTHOUGH CLEARING
SKIES HAVE BEEN NOTED FARTHER WEST/NORTHWEST ACROSS THE
AREA...PATCHY FOG IS QUICKLY REPLACING MUCH OF THE CLEARING WHICH
HAS BEEN OBSERVED.
0.37" OF RAIN WAS OBSERVED HERE AT THE OFFICE FROM OVERNIGHT
CONVECTION...WITH ANYWHERE FROM A FEW TENTHS OF AN INCH TO AROUND
A HALF INCH OF RAIN...MAYBE MORE...LIKELY OBSERVED ACROSS MUCH OF
THE CWA. REMNANT MOISTURE FROM THIS RAINFALL IS PROVIDING
RELATIVELY HIGH SURFACE DEWPOINTS EARLY THIS MORNING...GENERALLY
IN THE MID 40S TO LOWER 50S ACROSS OUR CWA. WITH THE
AFOREMENTIONED CLEARING SKIES BEHIND THE PRIMARY AREA OF
CONVECTION...THE LOWER TROPOSPHERE IS RADIATING OUT VERY QUICKLY
THUS RESULTING IN NEAR-ZERO LOW LEVEL DEWPOINT DEPRESSIONS. IN
ADDITION THE LOW DEWPOINT DEPRESSION...THE LOW LEVEL WIND FIELD IS
ALSO DECREASING IN INTENSITY AS THE SURFACE TROUGH...CURRENTLY
OVER WESTERN NEBRASKA AND WESTERN KANSAS...APPROACHES FROM THE
WEST. THESE INGREDIENTS ARE PROVIDING THE DEVELOPING FOG WE HAVE
NOTICED ACROSS OUR WESTERN CWA THROUGH THE PAST FEW HOURS AND
THESE ARE TRENDS WHICH ARE EXPECTED TO CONTINUE THROUGH SUNRISE OR
SHORTLY THEREAFTER. GIVEN THIS...WENT AHEAD AND INTRODUCED PATCHY
FOG TO THE FORECAST FOR THIS MORNING.
MODEL GUIDANCE SUGGESTS DRY CONDITIONS WILL BE OBSERVED ACROSS OUR
AREA THROUGH MUCH OF TODAY ONCE THE CURRENT BATCH OF CONVECTION
PUSHES OFF TO THE EAST. AS A RESULT...DRY CONDITIONS ARE IN THE
FORECAST THROUGH MID AFTERNOON. BY MID TO LATE AFTERNOON
HOWEVER...FORECAST PROXIMITY SOUNDINGS FROM ACROSS OUR
SOUTH/SOUTHEASTERN CWA...PER THE NAM AND OPERATIONAL GFS...SUGGEST
THE CONVECTIVE TEMPERATURE WILL BE REACHED THUS PROVIDING THE
OPPORTUNITY FOR ISOLATED CONVECTION. WENT AHEAD WITH 20% POPS
ACROSS OUR SOUTH/SOUTHEAST DURING THE MID AND LATE AFTERNOON HOURS
AS A RESULT. IN ADDITION TO THE POSSIBILITY OF AFTERNOON
CONVECTION...GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC...AND
SREF-MEAN ALL SUGGEST THE MID LEVEL PERTURBATION...CURRENTLY OVER
THE NORTHERN PLAINS...WILL CONTINUE MOVING SOUTHEAST AND NEAR OUR
AREA LATE THIS AFTERNOON. GUIDANCE CURRENTLY SUGGESTS THERE SHOULD
BE JUST ENOUGH LOW TO MID TROPOSPHERIC MOISTURE AND JUST ENOUGH
OMEGA...PERHAPS APPROACHING 5-UBAR/S...FOR PRECIPITATION
PRODUCTION ACROSS WESTERN PORTIONS OF OUR CWA BEGINNING MID TO
LATE THIS AFTERNOON. WENT AHEAD WITH ~20% POPS ACROSS OUR WEST MID
TO LATE AFTERNOON AS A RESULT.
ANY SURFACE-BASED CONVECTION ACROSS OUR SOUTH/SOUTHEAST SHOULD
DIMINISH SHORTLY AFTER SUNSET THIS EVENING AS DIABATIC HEATING IS
LOST. PRECIPITATION ACROSS OUR WEST HOWEVER SHOULD SPREAD ACROSS
THE SOUTHWESTERN HALF OF OUR CWA TONIGHT AS OMEGA...AHEAD OF THE
APPROACHING MID LEVEL PERTURBATION...CONTINUES OVERTAKING THE
AREA. TAKING AN EVEN-AVERAGE OF THE NAM...OPERATIONAL
GFS...EC...AND SREF-MEAN PROVIDES RAINFALL AMOUNTS OF ~0.05"
ACROSS SOUTHWESTERN PORTIONS OF OUR CWA 00Z-06Z AND AS A
RESULT...WENT AHEAD WITH 30%-40% POPS ACROSS OUR SOUTHWESTERN CWA
00Z-06Z. PRECIPITATION CHANCES QUICKLY COME TO AN END ACROSS OUR
CWA BY 06Z HOWEVER AS THE MID LEVEL PERTURBATION CLEARS THE AREA
AND OMEGA IS LOST. DRY CONDITIONS ARE CURRENTLY FORECAST 06Z-12Z.
SHOULD AFTERNOON CONVECTION ACROSS OUR SOUTH/SOUTHEAST BE
REALIZED...FORECAST PROXIMITY SOUNDINGS...PER THE NAM AND
OPERATIONAL GFS...SUGGEST 500 TO 600J/KG 0-1KM MLCAPE WILL BE
AVAILABLE FOR UPDRAFT PRODUCTION. NOT OVERLY IMPRESSIVE BUT GIVEN
THE LOW FREEZING HEIGHTS TYPICAL THIS TIME OF YEAR...WILL GO AHEAD
AND MENTION SMALL HAIL IN THE HWO. IN ADDITION TO THE SMALL HAIL
THREAT...FORECAST PROXIMITY SOUNDINGS...IN PARTICULAR FROM THE
NAM...SUGGEST DEEP INVERTED-V SOUNDINGS TO AROUND 800MB WILL BE IN
EXISTENCE...THUS PRESENTING THE OPPORTUNITY FOR BRIEF GUSTY WINDS.
GIVEN THIS THREAT...WILL ALSO MENTION SUB-SEVERE WIND GUSTS IN THE
HWO.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 441 AM CDT SAT MAR 30 2013
PRIMARY FORECAST CONCERN FOR THE LONG TERM RESIDES SUNDAY NIGHT
AND MONDAY AS A COLD FRONT PUSHES IN FROM THE NORTH ACROSS THE
CWA. THE MAIN CHALLENGES DURING THE LONG TERM WILL BE
PRECIPITATION AND TEMPERATURES...MAINLY SUNDAY THROUGH MONDAY.
PRESSURE RISES ON THE ORDER OF 10 TO 15 MB WILL BE REALIZED BEHIND
THE FRONT SUNDAY NIGHT. TEMPERATURES ACROSS THE CWA WILL DROP
ROUGHLY 40 DEGREES IN MOST LOCATIONS FROM SUNDAY AFTERNOON TO
MONDAY MORNING...BRINGING A COLD REMINDER OF WINTER-LIKE
TEMPERATURES TO THE AREA. IN OTHER WORDS...WE WILL GO FROM
SLIGHTLY ABOVE NORMAL TEMPERATURES SUNDAY AFTERNOON...TO WELL
BELOW NORMAL TEMPERATURES MONDAY WHEN HIGHS ARE FORECAST TO BE
AROUND 20 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. NORMAL HIGH
TEMPERATURES FOR THIS TIME OF YEAR RANGE FROM THE MID 50S TO THE
UPPER 50S...AND NORMAL LOW TEMPERATURES FOR THIS TIME OF YEAR
RANGE FROM THE LOWER 30S TO THE MID 30S. 850MB TEMPERATURES ARE
TRENDING WARMER INITIALLY BEHIND THE COLD FRONT...SO NOT MUCH SNOW
IS EXPECTED AT THE BEGINNING OF THE EVENT. FORECAST SOUNDINGS ARE
DEPICTING A RELATIVELY WARM LAYER NEAR THE SURFACE...AND THE
REALITY IS THIS LAYER NEAR THE SURFACE WOULD NEED TO COOL MUCH
QUICKER TO GET ANY SNOW TO REACH THE SURFACE. GOING TO HOLD OFF ON
THE MENTION OF ANY SNOW UNTIL AFTER MIDNIGHT ON SUNDAY. THESE
PRECIPITATION CHANCES APPEAR TO BE MOSTLY SYNOPTICALLY DRIVEN. THE
RIGHT REAR QUADRANT OF THE UPPER LEVEL JET WILL SET UP OVER THE
CWA...AND HENCE AN AREA OF DIVERGENT AIR ALOFT WILL BE
REALIZED...HELPING INDUCE RISING AIR BELOW THE JET MONDAY MORNING.
HOWEVER...LITTLE TO NO PRECIPITATION IS EXPECTED AFTER 12Z MONDAY.
IF ANYTHING...THERE MIGHT BE SOME ACTIVITY ACROSS OUR KANSAS
COUNTIES MONDAY MORNING WHERE A SLIGHT CHANCES OF PRECIPITATION
WILL EXIST. CONFIDENCE IS PRETTY HIGH REGARDING THE OUTLOOK OF
PRECIPITATION AFTER 12Z AS THERE IS GOOD AGREEMENT BETWEEN THE
NAM...GFS AND EC.
NORTHWESTERLY FLOW ALOFT WILL DOMINATE THE WEATHER PATTERN THROUGH
MOST OF THE LONG TERM PERIOD. OUTSIDE OF MONDAY...PRECIPITATION
CHANCES ARE LOOKING VERY SLIM. THE LATEST RUN OF THE EC IS NOW
HINTING AT SOME POTENTIAL RAINFALL ACROSS THE CWA WEDNESDAY NIGHT
THROUGH THURSDAY. HOWEVER...THE GFS DOES NOT HAVE ANYTHING NEAR
THE AMOUNT OF COVERAGE OR INTENSITY. SINCE THE LATEST RUN OF THE
EC IS VASTLY DIFFERENT THAN THE PREVIOUS RUN...GOING TO LEAVE THIS
RAIN MENTION OUT FOR NOW UNTIL SOME CONSISTENCY BECOMES EVIDENT
BETWEEN THE MODELS.
HIGH TEMPERATURES WILL BE NEAR NORMAL FOR BOTH WEDNESDAY AND
THURSDAY. TUESDAY HIGHS...ON THE OTHER HAND...WILL BE ROUGHLY 10
DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. AND LASTLY...FRIDAY
AFTERNOON HIGHS WILL BE ABOVE NORMAL...WITH LOCATIONS ACROSS THE
SOUTH FLIRTING WITH 70 DEGREES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1212 PM CDT SAT MAR 30 2013
THIS AFTN: VFR WITH A 7-10K FT MID-LEVEL CIGS GRADUALLY INVADING
FROM THE NW. N WINDS GUST TO 20 KTS AT TIMES.
TNGT: VFR MID-LEVEL CIGS WILL CONT WITH A CHANCE FOR A BRIEF SHWR
OR SPRINKLES. AFTER 08Z CLEARING. WINDS DIMINISH TO LESS THAN 10
KTS AND THEN SHIFT TO WNW.
SUN THRU 18Z: VFR WITH ESSENTIALLY SKC. NW WINDS AVERAGE 10 KTS.
CIG CONFIDENCE: HIGH
VSBY CONFIDENCE: HIGH
WIND CONFIDENCE: HIGH
WX CONFIDENCE: HIGH
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...BRYANT
LONG TERM...GUERRERO
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1122 PM CDT FRI MAR 29 2013
.SYNOPSIS...
ISSUED AT 318 PM CDT FRI MAR 29 2013
H5 HAND ANALYSIS THIS MORNING IS INDICATING BROAD LOW
AMPLITUDE FLOW ACROSS THE LOWER 48...WITH EMBEDDED SHORTWAVES NOTED
OVER THE NORTHERN ROCKIES OF IDAHO AND MONTANA. ABUNDANT MID LEVEL
INSTABILITY AND MID LEVEL ALTO CU HAS TRACKED INTO WESTERN AND
CENTRAL NEBRASKA THIS MORNING...WITH RADAR INDICATING HIGHLY
ELEVATED SHOWERS...NONE OF WHICH IS REACHING THE GROUND ATTM. AT THE
SURFACE...A LEE SIDE TROUGH HAS BEGUN TO DEEPEN ACROSS THE PANHANDLE
AND FAR EASTERN COLORADO OVER THE PAST COUPLE OF HOURS. THIS HAS
RESULTED IN INCREASED SRLY WINDS THIS AFTERNOON AND INCREASED LOW
LEVEL MOISTURE...WITH DEW POINTS BEGINNING TO REACH INTO THE LOWER
40S AS OF 3 PM CDT. TEMPERATURES AS OF 3 PM CDT RANGED FROM 64
DEGREES AT VALENTINE TO 71 DEGREES AT OGALLALA.
&&
.UPDATE...
ISSUED AT 817 PM CDT FRI MAR 29 2013
THE SHOWERS AND THUNDERSTORMS HAVE LARGELY MOVED OFF TO THE EAST.
GIVEN THE RESIDUAL MOISTURE ALOFT WHICH WILL REMAIN IN PLACE THROUGH
SATURDAY EVENING. ISOLATED SHOWERS ARE POSSIBLE THROUGH MIDNIGHT
TONIGHT AND THEN AGAIN SATURDAY MORNING WITH SHOWERS AND
THUNDERSTORMS POSSIBLE SATURDAY AFTERNOON AS ANOTHER DISTURBANCE
MOVES THROUGH IN THE NORTHWEST FLOW ALOFT.
A NEW FORECAST IS OUT.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 318 PM CDT FRI MAR 29 2013
MAIN FORECASTING CHALLENGES
OVER THE NEXT 24 HOURS ARE THUNDERSTORM POTENTIAL AND ASSOCIATED
PRECIPITATION CHANCES TONIGHT...THEN LOW PRECIPITATION CHANCES FOR
SATURDAY...IN PARTICULAR SATURDAY AFTERNOON. FOR TONIGHT...AM
EXPECTING SOME ISOLATED TSRA INITIATION INVOF OF SURFACE TROUGH AXIS
LATER THIS AFTERNOON. BASED ON THE LATEST NAM AND RUC SOLNS...THIS
SHOULD BE SOMEWHERE FROM AROUND OGALLALA TO NORTHERN CHERRY COUNTY
BY 21Z THIS AFTERNOON. AM EXPECTING ISOLATED CONVECTION TO FIRE
INVOF OF THIS FEATURE DURING THE 21Z TO 00Z TIME FRAME LATER THIS
AFTERNOON. DECENT MID LEVEL FLOW...WILL TRACK ANY ISOLATED
CONVECTION QUICKLY EAST INTO THE CENTRAL AND EASTERN CWFA LATER THIS
EVENING AND OVERNIGHT. CONVECTION IS EXPECTED TO BECOME BETTER
ORGANIZED IN THE EASTERN CWFA OVERNIGHT AS A NICE LOW LEVEL JET
PUSHES NORTH INTO EASTERN NEBR...THE NOSE OF WHICH PUSHES INTO OUR
NERN ZONES. FOR PRECIPITATION CHANCES TONIGHT...FAVORED POPS AROUND
20 PERCENT...ALONG AND WEST OF HIGHWAY 83...INCREASING THEM EASTWARD
TO AROUND 50 PERCENT IN THE NERN CWA. AS FOR THE THREAT OF SEVERE
THUNDERSTORMS TONIGHT...THE LATEST SWODY1 HAS A SEE TEXT ACROSS OUR
SWRN ZONES AND CENTRAL SANDHILLS MAINLY FOR EARLY EVENING CONVECTION
TIED TO PEAK HEATING. AT THIS JUNCTURE...SOME GUSTY WINDS MAY
ACCOMPANY THE STRONGEST STORMS GIVEN THE DRY CONDS BLO 10000 FT AGL
AND EXPECTED HIGH BASED TSRAS IN THE WEST. EVEN IN LIGHT OF WET BULB
ZEROES OF AROUND 9000 FT MSL...LARGE HAIL THREAT WILL BE MINIMAL AS
DEEP LAYER SHEAR IS ONLY AROUND 30 KTS AND FREEZING LEVELS ARE
AROUND 5 TO 7 THOUSAND FT AGL.
FOR SATURDAY...NORTHWESTERLY WINDS WILL DEVELOP BEHIND EXITING LOW
PRESSURE AND MAY BECOME GUSTY DURING THE AFTERNOON HOURS. WITH
SURFACE HEATING...MID LEVEL LAPSE RATES WILL STEEPEN SIGNIFICANTLY
DURING THE AFTERNOON HOURS...AND WILL CONTINUE MENTION OF ISOLATED
SHOWERS. LI`S ARE BARELY NEGATIVE TOMORROW AFTERNOON AND WILL FORGO
MENTION OF THUNDER ATTM. HIGHS SATURDAY WILL BE COOLER THAN TDYS
READINGS. BASED ON H85 TEMPS AND GOOD MIXING...HIGHS WILL RANGE FROM
THE 50S NORTH...TO THE LOWER 60S IN THE SOUTH.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 318 PM CDT FRI MAR 29 2013
SATURDAY NIGHT WILL SEE A DISTURBANCE PUSHING SOUTH AND AN ARCTIC
COLD FRONT DIPPING SOUTH ACROSS THE NORTHERN PLAINS. BY SUNDAY
AFTERNOON THE COLD FRONT WILL BE PUSHING INTO NRN NEBRASKA. SHOULD
SQUEAK OUT ANOTHER NICE DAY WITH HIGHS IN THE 60S FOR MOST OF THE
CWA. PORTIONS OF NORTH CENTRAL WILL SEE HIGHS ONLY IN THE 50S AS THE
COLD FRONT ARRIVES BEFORE PEAK HEAT. ALSO GOING TO SEE SOME SHOWERS
DEVELOP ALONG/AHEAD OF THE FRONT...MAINLY WHERE THERE IS BETTER
MOISTURE TO THE EAST. BY SUNDAY NIGHT COLD AIR WILL PUSH ACROSS THE
AREA. NOT A GREAT CHANCE FOR PRECIP...BUT COLD AIR ALOFT WILL CREATE
SOME STEEP LAPSE RATES. ALSO AS TEMPS FALL A MIX OR CHANGE TO SNOW
CAN BE EXPECTED.
MONDAY WILL FEEL THE COLD ARCTIC AIR AS HIGHS ONLY WARM INTO THE MID
30S TO MID 40S. PRECIP WILL BE PUSHING SOUTH...SO HIGHS MAY ACTUALLY
BE ABLE TO WARM UP A LITTLE MORE THAN FORECAST AS APRIL SUNSHINE
ARRIVES FOR THE AFTERNOON.
COLD AIR IS SHORT LIVED AS CENTER OF HIGH SHIFTS TO THE EAST FOR
TUESDAY...WITH RETURN SOUTHERLY FLOW BY TUESDAY AFTERNOON. NOT A
FAST REBOUND ON TUESDAY AS HIGHS ONLY IN THE 40S TO LOW 50S.
WEDNESDAY INTO THURSDAY WILL CONTINUE TO SEE A REBOUND OF TEMPS.
SURF HIGH CONTINUES TO PUSH TO THE SE WITH MORE WARM AIR TO PUSH
NORTHWARD AND THE BACKSIDE OF THE HIGH. 850 MB TEMPS PUSH INTO THE
SINGLE DIGITS ABOVE ZERO AND CLOSE TO 10 IN THE WEST WITH GUIDANCE
CLOSE TO 60. PRECIP CHANCES DO NOT LOOK GOOD THROUGH THE WEEK...AS
GULF MOISTURE REMAINS SHUT OFF AND MODELS CONTINUE A DRY BL. AN
UPPER LEVEL DISTURBANCE LATE IN THE WEEK MAY BRING SOME LIGHT
PRECIP...BUT WILL HAVE TO BE A TOP DOWN SATURATION AND DO NOT HAVE
IN THE FORECAST ATTM.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1122 PM CDT FRI MAR 29 2013
VFR IS GENERALLY EXPECTED OVERNIGHT THROUGH 20Z.
THEREAFTER...ANOTHER UPPER LEVEL DISTURBANCE...CURRENTLY ACROSS
SCNTL MT...WILL MOVE SOUTHEAST THROUGH WESTERN AND SOUTH CENTRAL
NEBRASKA PRODUCING ISOLATED TO SCATTERED SHRA AND TSTM COVERAGE.
THESE STORMS ARE EXPECTED TO EXIT THE FCST AREA BY AROUND 03Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CDC
SYNOPSIS...CLB
SHORT TERM...CLB
LONG TERM...MASEK
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
739 PM EDT SUN MAR 31 2013
.SYNOPSIS...
MILD CONDITIONS AND SCATTERED SHOWERS AND POSSIBLY AN ISOLATED
THUNDERSTORM CAN BE EXPECTED THROUGH MONDAY. THE FIRST OF TWO
COLD FRONTS WILL CROSS THE AREA MONDAY MORNING ACCOMPANIED BY
SHOWERS. THE SECOND FRONT WILL BE DRY AND MOVE ACROSS THE AREA
EARLY TUE. CANADIAN HIGH PRESSURE WILL BRING A RETURN OF CHILLY
AIR THROUGH THE MIDDLE OF THE WEEK. UNSETTLED WEATHER WILL ARRIVE
FROM THE GULF OF MEXICO THURSDAY AND FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 645 PM SUNDAY...LATEST KLTX AND SURROUNDING 88DS ILLUSTRATE
SCATTERED CONVECTION MOVING ENE AT A GOOD CLIP...WITH ACTIVITY
AFFECTING THE WESTERN PORTIONS OF THE ILM CWA AT THE MOMENT. THE
PCPN TO CONTINUE ITS TREK EASTWARD THIS EVENING...WITH POPS RE-
ORIENTED TO CURRENT ACTIVITY AND ITS PROGRESSION ACROSS THE FA
THIS EVENING. A WEAK RESULTANT WIND/SEA BREEZE BOUNDARY HAS PUSHED
SLIGHTLY INLAND THIS AFTERNOON AND EVENING...AND WILL PROVIDE A
WEAKENING TREND TO THE CONVECTION THAT PUSHES ACROSS IT AND INTO A
COOL STABLE MARINE LAYER ALONG THE IMMEDIATE COAST. POPS HAVE BEEN
RE-ALIGNED ALONG THE IMMEDIATE COAST FOR THIS EVENING. IN
ADDITION...PCPN PROGGED TO DROP SOUTHWARD WITH TIME AS A SFC COLD
FRONT SLOWLY SUPPRESSES TO THE SOUTH OVERNIGHT AND MONDAY. LATEST
NAM AND HRRR OUTPUT ILLUSTRATE AND BASICALLY CONFIRM THIS
INCREASING PCPN COVERAGE AT THE MOMENT...AND CONTINUING OVERNIGHT
ACROSS THE FA. CURRENT MIN TEMPS LOOKING AOK WITH VERY LITTLE IF
ANY TWEAKING NEEDED AT THIS TIME.
PREVIOUS DISCUSSION..............................................
AS OF 3 PM SUNDAY...DEEP AND MODERATE SW FLOW PREVAILS ACROSS THE
REGION PRESENTLY AND SO FAR THIS SWIFT FLOW HAS OVERPOWERED AND
PREVENTED WHAT MINUSCULE INSTABILITY AND LIFT DOES EXIST FROM
BLOSSOMING INTO PRECIPITATING CONVECTION. A FEW LIGHT SHOWERS HAVE
FORMED BRIEFLY BUT HAVE BEEN INSIGNIFICANT THUS FAR. ALSO THERE
APPEARS TO BE A BIT OF MID-LEVEL DRY AIR INDUCING A WEAK CAP FOR
ADDED INHIBITION. TEMPERATURES HAD RISEN INTO THE 70S THIS AFTN
AWAY FROM THE IMMEDIATE COAST WHERE CHILLY SEA SFC TEMPS RESIDE.
OVERNIGHT IT SEEMS APPARENT THAT COLUMN MOISTURE WILL DEEPEN AND
ALL SHORT-RANGE MODELS POINT TO INCREASING CHANCES OF SHOWERS IN
SOME DEGREE OR ANOTHER...MOST NOTABLY AFTER MIDNIGHT INTO EARLY
MORNING OF MONDAY. SEVERAL NOTEWORTHY PERTURBATIONS ALOFT IN THE
WSW FLOW WILL TRACK OVERHEAD LATE TONIGHT...AND OVERALL WE CAN
EXPECT UPPER TROUGHING OVER THE REGION TO DEEPEN SLIGHTLY. ALL
THESE FACTORS POINT TO AN INCREASING CHANCE OF PCPN AND TONIGHTS
FORECAST WILL ADVERTISE LIKELY POP VALUES.
EXPECT MILD MINIMUM TEMPERATURES OVERNIGHT GIVEN WINDS AND CLOUD
COVER IN A WARM SECTOR REGIME AS A WARM FRONT HAS ALREADY LIFTED
WELL NORTH OF THE REGION. IN FACT TEMPERATURE CURVES WILL HOLD
PRETTY DARN FLAT FROM LATE EVENING ONWARD. COMPLICATING THIS ARE
COLD NEAR-SHORE WATERS IN ONSHORE FLOW TONIGHT...BUT THINK UPPER
50S TO LOWER 60S COASTAL ZONES TO THE MIDDLE AND UPPER 50S INLAND
LOOKS GOOD.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...TWO SEPARATE COLD FRONTS ARE SET TO IMPACT
THE REGION DURING THE PERIOD. FIRST FRONT WILL BE NEAR THE COAST
MON MORNING...SLOWLY PUSHING OFF THE COAST AS THE DAY WEARS ON.
EXITING SHORTWAVE AND WEAKLY DIVERGENT FLOW ALOFT...ALONG WITH THE
SLOW TO MOVE BOUNDARY AND DIURNAL INSTABILITY WILL KEEP PRECIP
CHANCES ELEVATED MON. COAST IS FAVORED OVER INLAND WITH SUBSIDENCE
BEHIND EXITING WAVE AND DRY AIR MOVING IN FROM THE NORTH HELPING
DRY INLAND AREAS OUT. LOW CLOUD WILL HOLD ON INTO THE AFTERNOON
BEFORE DRY AIR ARRIVES. INTERIOR NC WILL CLEAR OUT FIRST FOLLOWED
BY INLAND SC AND FINALLY THE COAST. HIGHS WILL BE NEAR TO ABOVE
CLIMO MON...LOW TO MID 70S IN MOST AREAS.
FIRST FRONT MOVES OFF THE COAST MON NIGHT WITH SKIES CLEARING AND
WINDS VEERING FROM WEST-NORTHWEST TO NORTHEAST BU TUE MORNING.
RELATIVELY DRY MID LEVELS COMBINED WITH LITTLE FORCING AHEAD OF AND
ALONG THE NEXT FRONT. MAY SEE AN INCREASE IN MID CLOUDS WITH THE
PASSAGE OF THE FRONT TUE MORNING BUT PRECIP IS NOT ANTICIPATED.
ALTHOUGH COLD FRONT WILL BE SOUTH OF THE AREA THE RELATIVELY FLAT
UPPER PATTERN KEEPS THE COLDEST AIR TRAPPED TO THE NORTH.
TEMPERATURES MON NIGHT SHOULD BE FAIRLY UNIFORM WITH MOST AREAS IN
THE UPPER 40S. GRADUAL COLD ADVECTION TUE...INCREASING A LITTLE IN
THE AFTERNOON...WILL KEEP HIGHS IN THE MID 60S. WEAK WARM
ADVECTION JUST ABOVE THE SURFACE STARTS LATE TUE NIGHT. WITH
COLDER AIR IN PLACE THIS IS NOT LIKELY TO HAVE MUCH OF AN
IMPACT...THOUGH PORTIONS OF SC MAY RUN A FEW DEGREES WARMER THAN
THE REST OF THE FORECAST AREA AS CLOUDS INCREASE.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 3 PM SUNDAY...SURFACE HIGH PRESSURE WILL RIDGE INTO AREA ON
WED FROM SYSTEM OVER THE UPPER MID WEST. THIS HIGH WILL SHIFT EAST
OVER THE MID ATLANTIC STATES THROUGH THURS AS A LOW PRESSURE SYSTEM
DEVELOPS OVER THE GULF COAST. A SHALLOW COOL AIR MASS FROM THE NORTH
WILL REACH INTO THE LOCAL AREA WHILE WARM MOIST AIR WILL BEGIN TO
PUSH UP FROM THE SOUTH. SHOULD SQUEEZE OUT A DECENT DAY ON WED BUT
MAY SEE SOME CLOUDS DEVELOP AS WARM MOIST LOW LEVEL SW FLOW RUNS
OVER THE COOL NE FLOW AT THE SURFACE. PCP WATER VALUES REMAIN AROUND
A QUARTER OF INCH OVER NORTHERN TIER ZONES WHILE NORTHEAST SC MAKES
IT UP TO AN INCH. CLOUDS AND PCP WILL EVENTUALLY SPREAD NORTH
THROUGH WED NIGHT INTO THURS. BY THURS THE HIGH SHIFTS EAST INTO THE
ATLANTIC WHILE LOW PRESSURE DEEPENS AS IT SHIFTS EAST OVER THE GULF
COAST. OVERALL MOISTURE WILL INCREASE THROUGH THURS WITH PCP WATER
VALUES REACHING UP NEAR 1.25 INCHES BY THURS MORNING AND UP TO 1.5
INCHES LATE THURS AND CLOSE TO 1.75 INCHES EARLY FRI. LOOKS LIKE
GREATEST QPF WITH THIS EVENT WILL COME THURS NIGHT INTO EARLY FRI AS
LOW LIFTS OFF TO THE NORTHEAST TRACKING UP ALONG THE SOUTHEAST
COAST. LOW LEVEL WINDS INCREASE OUT OF THE SOUTH UP CLOSE TO 50 KTS
BY THURS NIGHT. EXPECT BEST LIFT AND MOISTURE THROUGH THURS NIGHT
WITH MODERATE TO HEAVY RAIN POSSIBLE ESPECIALLY AS CONVECTION
DEVELOPS ON THE EAST SIDE OF LOW.
DEEP NW FLOW WILL DEVELOP ON THE BACK END OF THE LOW PRESSURE SYSTEM
AS IT LIFTS RAPIDLY OFF TO THE NORTHEAST THROUGH LATE FRI. THE LOW
SHOULD REACH HATTERAS BY FRI AFTERNOON AND THE NEW ENGLAND COAST BY
FRI NIGHT. COOL AND DRY CANADIAN HIGH PRESSURE WILL BUILD IN BEHIND
IT THROUGH SATURDAY. AIR MASS WILL BEGIN TO MODIFY THROUGH THE
WEEKEND AS HIGH PRESSURE CENTER MOVES OVER THE SOUTHEAST WITH RETURN
FLOW SETTING UP BY SUNDAY AS THE HIGH SHIFTS OFF THE COAST.
AS FOR TEMPS...SHALLOW COOL AIR WILL BE IN PLACE WED INTO THURS WITH
TEMPS ONLY REACHING AROUND 60 DEGREES ON WED AND HOLDING IN THE 50S
IN PLACES WITH CLOUDS. WINDS WILL COME AROUND TO THE E-SE BRINGING
WITH WAA HEADING INTO THURS NIGHT. THIS SHOULD KEEP TEMPS UP CLOSER
TO 50 FOR LOWS THURS NIGHT IN CLOUDS AND RAIN. TEMPS SHOULD START
OUT WARMER ON FRI BUT ONCE DEEP NW WINDS DEVELOP ON BACK END OF LOW
THROUGH FRI AFTN INTO THE EVENING...COOL AIR WILL BRING TEMPS DOWN.
OVERNIGHT LOWS SHOULD DROP INTO THE 40S MOST PLACES. COOLING WILL BE
BRIEF AS MID TO UPPER RIDGE BUILDS UP THE SOUTHEAST COAST THROUGH
SAT WITH H5 HEIGHTS RISING AND LOW LEVEL RETURN FLOW DEVELOPING.
OVERALL...LONG TERM PERIOD WILL START OUT COOL WITH OVERNIGHT LOWS
IN THE 30S POSSIBLY WED NIGHT BUT WILL END UP WITH SPRING LIKE
WEATHER BY THE END OF THE WEEKEND WITH SUNSHINE AND TEMPS IN THE
70S.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 00Z...RADAR IMAGERY SHOWS A LINE OF SHRA/TSRA OVER OUR WESTERN
COUNTIES CURRENTLY MOVING THROUGH KFLO. TEMPO MVFR VSBYS ARE
CERTAINLY POSSIBLE IN HEAVIER SHOWERS AS THIS LINE MOVES ACROSS OUR
CWA THIS EVENING.
A WET TAF PERIOD IS IN STORE WITH AN APPROACHING SHORTWAVE AND A
WEAK COLD FRONT SAGGING TOWARDS OUR AREA. EXPECT LIGHT TO MODERATE
SHOWERS WITH ISO T-STORMS OVERNIGHT THROUGH MONDAY MORNING. VFR CIGS
WILL LIKELY PREVAIL TONIGHT...BUT MVFR CIGS COULD DEVELOP MONDAY
MORNING IN AREAS THAT RECEIVE MORE PERSISTENT RAINFALL. SOUTHWEST
WINDS 8 TO 12 KTS WILL PERSIST FOR MUCH OF THE PERIOD...BECOMING
MORE WESTERLY TMRW AFTERNOON. HAVE INCLUDED VCSH INTO THE AFTERNOON
HOURS AS THE SFC BOUNDARY MAY LINGER NEAR THE COAST.
EXTENDED OUTLOOK...VFR TUESDAY AND WEDNESDAY. SHOWERS AND SUB-VFR
CONDITIONS LIKELY THURSDAY AND FRIDAY AS LOW PRESSURE MOVES UP THE
ATLANTIC COAST.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 645 PM SUNDAY...WEAK RESULTANT/SEA BREEZE BOUNDARY NOTED BY
FINE LINE PUSHING INLAND FROM THE COAST WITH THE 0.5 DEGREE KLTX
88D. THIS HAS RESULTED WITH S TO SSW 15+ KT WINDS NEARSHORE. WITH
TIME THIS EVENING AND OVERNIGHT...WINDS WILL RE-ORIENT THEMSELVES
BACK TO A SYNOPTIC SW AT 15-25 KT. SSTS IN THE 50S PREVENTING THE
30KT OR STRONGER WIND GUSTS FROM REACHING THE OCEAN SFC ACROSS THE
ILM COASTAL WATERS. THE TIGHTENED SFC PG WILL CONTINUE TO SUPPORT
THE SUSTAINED 15-25 KT WIND SPEEDS ACROSS THE LOCAL WATERS
OVERNIGHT. SIGNIFICANT SEAS PRIMARILY DOMINATED BY THE 5 TO 6 SECOND
AVERAGE PERIOD WIND DRIVEN WAVES. OF NOTE...A 1 TO 2 FOOT ESE
GROUND SWELL AT 13+ SECOND PERIODS IS AFFECTING THE LOCAL WATERS.
OVERALL...LOOKING AT 3 TO 6 FOOT SIGNIFICANT SEAS WITH 7 FOOTERS
POSSIBLE ACROSS THE OUTER WATERS OFF CAPE FEAR.
PREVIOUS DISCUSSION..............................................
AS OF 3 PM SUNDAY...SMALL CRAFT ADVISORIES WILL REMAIN HOISTED
OVERNIGHT FOR ALL WATERS FOR GUSTS TO 25-30 KT AND GENERALLY 3-6
FOOT SEAS AND HIGHEST OFFSHORE. IT APPEARS THE PRESSURE GRADIENT
WILL LOOSEN INTO DAYBREAK MONDAY AS A WEAK COLD FRONT SAGS S INTO
THE FORECAST AREA FROM THE NW...ALLOWING WINDS TO MELLOW WELL
BELOW ADVISORY CRITERIA. SEAS MAY REQUIRE ANOTHER FEW HOURS TO
RECOVER AND THE ADVISORIES WILL RUN TO 9AM NC WATERS AND 6AM SC
WATERS DUE TO THE BUILDING TREND EXPECTED TONIGHT...HIGHEST SEAS
OUTER PORTION AROUND THE FRYING PAN SHOAL. SHORT-CRESTED WAVES
DUE TO SHORT WAVE PERIODS/INTERVALS WILL MAKE FOR STEEP WAVES
ADDING TO THE WIND HAZARD. ADDITIONALLY MARINERS SHOULD BE AWARE
THAT A FEW TSTMS WILL BE FAVORED OVER THE OUTER WATERS AND WEST
WALL OF THE GULF STREAM OVERNIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...SOUTHWEST FLOW MON BECOMES WEST-NORTHWEST AS
COLD FRONT MOVES SOUTH ACROSS THE WATERS. FRONT WILL BE SLOW TO MOVE
WITH OFFSHORE FLOW NOT DEVELOPING UNTIL MON NIGHT. SPEEDS WILL BE
10 TO 15 KT INTO MON AFTERNOON BUT DROP AS BOUNDARY REACHES THE
WATERS. WEAK GRADIENT BEHIND THE FRONT AND LACK OF SIGNIFICANT
COLD ADVECTION KEEP WINDS 10 KT OR LESS INTO TUE. A SECOND FRONT
WILL PUSH SOUTH TUE MORNING...REINFORCING NORTHERLY FLOW. THIS
FRONT ALSO LACKS A SIGNIFICANT COLD SURGE WITH PROLONGED STEADY
COLD ADVECTION BEHIND IT INSTEAD. SPEEDS WILL NOT INCREASE
APPRECIABLY BEHIND THE FRONT. WINDS MAY OCCASIONALLY EXCEED 10 KT
BUT OVERALL 10 KT SHOULD BE SUFFICIENT. REDUCTION IN WINDS THROUGH
THE PERIOD WILL TRANSLATE TO SEAS FALLING FROM 3 TO 5 FT AT THE
START OF THE PERIOD TO 2 TO 4 FT MON NIGHT AND 2 TO 3 FT TUE/TUE
NIGHT.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 3 PM SUNDAY...WINDS WILL VEER AROUND FROM THE N TO THE NE AS
HIGH PRESSURE BUILDS INTO THE WATERS WED. IN GENERAL EXPECT WINDS 15
KTS OR LESS AND SEAS 3 FT OR LESS THROUGH WED.
BY WED NIGHT INTO THURS HIGH PRESSURE WILL SHIFT OFF SHORE AS LOW
PRESSURE DEEPENS OVER THE GULF COAST AND THEN MOVES UP THROUGH THE
SOUTHEAST THURS NIGHT INTO FRI. NORTHEAST WINDS WILL INCREASE AND
VEER AROUND FROM THE NE TO E WED NIGHT THROUGH THURS AS GRADIENT
TIGHTENS BETWEEN THESE TWO SYSTEMS. WINDS WILL EVENTUALLY SHIFT
AROUND BECOMING INCREASINGLY ON SHORE THURS NIGHT. SEAS SHOULD REACH
UP INTO SCA THRESHOLDS BY THURS AFTN WITH INCREASING ON SHORE WINDS
UP TO 25 TO 30 KTS DRIVING SEAS UP TO 4 TO 6 FT NEAR SHORE BY THURS
EVENING AND UP TO 9 TO 11 FT OVER THE OUTER WATERS THROUGH THURS
NIGHT.
WINDS WILL SHIFT AROUND TO THE W-NW THROUGH FRI ON THE BACK END OF
THE LOW PRESSURE SYSTEM AS IT LIFTS OFF TO THE NORTHEAST. THIS OFF
SHORE FLOW WILL HELP TO LOWER SEAS NEAR SHORE BUT CAA AND TIGHTENED
GRADIENT FLOW WILL KEEP SEAS UP NEAR SCA IN OUTER WATERS THROUGH FRI
EVENING. BY SAT MORNING WINDS WILL DIMINISH TO 15 KTS OR LESS AND
SEAS WILL BE DOWN TO 2 TO 4 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR AMZ254-256.
SMALL CRAFT ADVISORY UNTIL 9 AM EDT MONDAY FOR AMZ250-252.
&&
$$
NEAR TERM...DCH/MJC
SHORT TERM...III
LONG TERM...RGZ
AVIATION...BJR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
727 PM EDT SUN MAR 31 2013
.SYNOPSIS...
MILD CONDITIONS AND SCATTERED SHOWERS AND POSSIBLY AN ISOLATED
THUNDERSTORM CAN BE EXPECTED THROUGH MONDAY. THE FIRST OF TWO
COLD FRONTS WILL CROSS THE AREA MONDAY MORNING ACCOMPANIED BY
SHOWERS. THE SECOND FRONT WILL BE DRY AND MOVE ACROSS THE AREA
EARLY TUE. CANADIAN HIGH PRESSURE WILL BRING A RETURN OF CHILLY
AIR THROUGH THE MIDDLE OF THE WEEK. UNSETTLED WEATHER WILL ARRIVE
FROM THE GULF OF MEXICO THURSDAY AND FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 645 PM SUNDAY...LATEST KLTX AND SURROUNDING 88DS ILLUSTRATE
SCATTERED CONVECTION MOVING ENE AT A GOOD CLIP...WITH ACTIVITY
AFFECTING THE WESTERN PORTIONS OF THE ILM CWA AT THE MOMENT. THE
PCPN TO CONTINUE ITS TREK EASTWARD THIS EVENING...WITH POPS RE-
ORIENTED TO CURRENT ACTIVITY AND ITS PROGRESSION ACROSS THE FA
THIS EVENING. A WEAK RESULTANT WIND/SEA BREEZE BOUNDARY HAS PUSHED
SLIGHTLY INLAND THIS AFTERNOON AND EVENING...AND WILL PROVIDE A
WEAKENING TREND TO THE CONVECTION THAT PUSHES ACROSS IT AND INTO A
COOL STABLE MARINE LAYER ALONG THE IMMEDIATE COAST. POPS HAVE BEEN
RE-ALIGNED ALONG THE IMMEDIATE COAST FOR THIS EVENING. IN
ADDITION...PCPN PROGGED TO DROP SOUTHWARD WITH TIME AS A SFC COLD
FRONT SLOWLY SUPPRESSES TO THE SOUTH OVERNIGHT AND MONDAY. LATEST
NAM AND HRRR OUTPUT ILLUSTRATE AND BASICALLY CONFIRM THIS
INCREASING PCPN COVERAGE AT THE MOMENT...AND CONTINUING OVERNIGHT
ACROSS THE FA. CURRENT MIN TEMPS LOOKING AOK WITH VERY LITTLE IF
ANY TWEAKING NEEDED AT THIS TIME.
PREVIOUS DISCUSSION..............................................
AS OF 3 PM SUNDAY...DEEP AND MODERATE SW FLOW PREVAILS ACROSS THE
REGION PRESENTLY AND SO FAR THIS SWIFT FLOW HAS OVERPOWERED AND
PREVENTED WHAT MINUSCULE INSTABILITY AND LIFT DOES EXIST FROM
BLOSSOMING INTO PRECIPITATING CONVECTION. A FEW LIGHT SHOWERS HAVE
FORMED BRIEFLY BUT HAVE BEEN INSIGNIFICANT THUS FAR. ALSO THERE
APPEARS TO BE A BIT OF MID-LEVEL DRY AIR INDUCING A WEAK CAP FOR
ADDED INHIBITION. TEMPERATURES HAD RISEN INTO THE 70S THIS AFTN
AWAY FROM THE IMMEDIATE COAST WHERE CHILLY SEA SFC TEMPS RESIDE.
OVERNIGHT IT SEEMS APPARENT THAT COLUMN MOISTURE WILL DEEPEN AND
ALL SHORT-RANGE MODELS POINT TO INCREASING CHANCES OF SHOWERS IN
SOME DEGREE OR ANOTHER...MOST NOTABLY AFTER MIDNIGHT INTO EARLY
MORNING OF MONDAY. SEVERAL NOTEWORTHY PERTURBATIONS ALOFT IN THE
WSW FLOW WILL TRACK OVERHEAD LATE TONIGHT...AND OVERALL WE CAN
EXPECT UPPER TROUGHING OVER THE REGION TO DEEPEN SLIGHTLY. ALL
THESE FACTORS POINT TO AN INCREASING CHANCE OF PCPN AND TONIGHTS
FORECAST WILL ADVERTISE LIKELY POP VALUES.
EXPECT MILD MINIMUM TEMPERATURES OVERNIGHT GIVEN WINDS AND CLOUD
COVER IN A WARM SECTOR REGIME AS A WARM FRONT HAS ALREADY LIFTED
WELL NORTH OF THE REGION. IN FACT TEMPERATURE CURVES WILL HOLD
PRETTY DARN FLAT FROM LATE EVENING ONWARD. COMPLICATING THIS ARE
COLD NEAR-SHORE WATERS IN ONSHORE FLOW TONIGHT...BUT THINK UPPER
50S TO LOWER 60S COASTAL ZONES TO THE MIDDLE AND UPPER 50S INLAND
LOOKS GOOD.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...TWO SEPARATE COLD FRONTS ARE SET TO IMPACT
THE REGION DURING THE PERIOD. FIRST FRONT WILL BE NEAR THE COAST
MON MORNING...SLOWLY PUSHING OFF THE COAST AS THE DAY WEARS ON.
EXITING SHORTWAVE AND WEAKLY DIVERGENT FLOW ALOFT...ALONG WITH THE
SLOW TO MOVE BOUNDARY AND DIURNAL INSTABILITY WILL KEEP PRECIP
CHANCES ELEVATED MON. COAST IS FAVORED OVER INLAND WITH SUBSIDENCE
BEHIND EXITING WAVE AND DRY AIR MOVING IN FROM THE NORTH HELPING
DRY INLAND AREAS OUT. LOW CLOUD WILL HOLD ON INTO THE AFTERNOON
BEFORE DRY AIR ARRIVES. INTERIOR NC WILL CLEAR OUT FIRST FOLLOWED
BY INLAND SC AND FINALLY THE COAST. HIGHS WILL BE NEAR TO ABOVE
CLIMO MON...LOW TO MID 70S IN MOST AREAS.
FIRST FRONT MOVES OFF THE COAST MON NIGHT WITH SKIES CLEARING AND
WINDS VEERING FROM WEST-NORTHWEST TO NORTHEAST BU TUE MORNING.
RELATIVELY DRY MID LEVELS COMBINED WITH LITTLE FORCING AHEAD OF AND
ALONG THE NEXT FRONT. MAY SEE AN INCREASE IN MID CLOUDS WITH THE
PASSAGE OF THE FRONT TUE MORNING BUT PRECIP IS NOT ANTICIPATED.
ALTHOUGH COLD FRONT WILL BE SOUTH OF THE AREA THE RELATIVELY FLAT
UPPER PATTERN KEEPS THE COLDEST AIR TRAPPED TO THE NORTH.
TEMPERATURES MON NIGHT SHOULD BE FAIRLY UNIFORM WITH MOST AREAS IN
THE UPPER 40S. GRADUAL COLD ADVECTION TUE...INCREASING A LITTLE IN
THE AFTERNOON...WILL KEEP HIGHS IN THE MID 60S. WEAK WARM
ADVECTION JUST ABOVE THE SURFACE STARTS LATE TUE NIGHT. WITH
COLDER AIR IN PLACE THIS IS NOT LIKELY TO HAVE MUCH OF AN
IMPACT...THOUGH PORTIONS OF SC MAY RUN A FEW DEGREES WARMER THAN
THE REST OF THE FORECAST AREA AS CLOUDS INCREASE.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 3 PM SUNDAY...SURFACE HIGH PRESSURE WILL RIDGE INTO AREA ON
WED FROM SYSTEM OVER THE UPPER MID WEST. THIS HIGH WILL SHIFT EAST
OVER THE MID ATLANTIC STATES THROUGH THURS AS A LOW PRESSURE SYSTEM
DEVELOPS OVER THE GULF COAST. A SHALLOW COOL AIR MASS FROM THE NORTH
WILL REACH INTO THE LOCAL AREA WHILE WARM MOIST AIR WILL BEGIN TO
PUSH UP FROM THE SOUTH. SHOULD SQUEEZE OUT A DECENT DAY ON WED BUT
MAY SEE SOME CLOUDS DEVELOP AS WARM MOIST LOW LEVEL SW FLOW RUNS
OVER THE COOL NE FLOW AT THE SURFACE. PCP WATER VALUES REMAIN AROUND
A QUARTER OF INCH OVER NORTHERN TIER ZONES WHILE NORTHEAST SC MAKES
IT UP TO AN INCH. CLOUDS AND PCP WILL EVENTUALLY SPREAD NORTH
THROUGH WED NIGHT INTO THURS. BY THURS THE HIGH SHIFTS EAST INTO THE
ATLANTIC WHILE LOW PRESSURE DEEPENS AS IT SHIFTS EAST OVER THE GULF
COAST. OVERALL MOISTURE WILL INCREASE THROUGH THURS WITH PCP WATER
VALUES REACHING UP NEAR 1.25 INCHES BY THURS MORNING AND UP TO 1.5
INCHES LATE THURS AND CLOSE TO 1.75 INCHES EARLY FRI. LOOKS LIKE
GREATEST QPF WITH THIS EVENT WILL COME THURS NIGHT INTO EARLY FRI AS
LOW LIFTS OFF TO THE NORTHEAST TRACKING UP ALONG THE SOUTHEAST
COAST. LOW LEVEL WINDS INCREASE OUT OF THE SOUTH UP CLOSE TO 50 KTS
BY THURS NIGHT. EXPECT BEST LIFT AND MOISTURE THROUGH THURS NIGHT
WITH MODERATE TO HEAVY RAIN POSSIBLE ESPECIALLY AS CONVECTION
DEVELOPS ON THE EAST SIDE OF LOW.
DEEP NW FLOW WILL DEVELOP ON THE BACK END OF THE LOW PRESSURE SYSTEM
AS IT LIFTS RAPIDLY OFF TO THE NORTHEAST THROUGH LATE FRI. THE LOW
SHOULD REACH HATTERAS BY FRI AFTERNOON AND THE NEW ENGLAND COAST BY
FRI NIGHT. COOL AND DRY CANADIAN HIGH PRESSURE WILL BUILD IN BEHIND
IT THROUGH SATURDAY. AIR MASS WILL BEGIN TO MODIFY THROUGH THE
WEEKEND AS HIGH PRESSURE CENTER MOVES OVER THE SOUTHEAST WITH RETURN
FLOW SETTING UP BY SUNDAY AS THE HIGH SHIFTS OFF THE COAST.
AS FOR TEMPS...SHALLOW COOL AIR WILL BE IN PLACE WED INTO THURS WITH
TEMPS ONLY REACHING AROUND 60 DEGREES ON WED AND HOLDING IN THE 50S
IN PLACES WITH CLOUDS. WINDS WILL COME AROUND TO THE E-SE BRINGING
WITH WAA HEADING INTO THURS NIGHT. THIS SHOULD KEEP TEMPS UP CLOSER
TO 50 FOR LOWS THURS NIGHT IN CLOUDS AND RAIN. TEMPS SHOULD START
OUT WARMER ON FRI BUT ONCE DEEP NW WINDS DEVELOP ON BACK END OF LOW
THROUGH FRI AFTN INTO THE EVENING...COOL AIR WILL BRING TEMPS DOWN.
OVERNIGHT LOWS SHOULD DROP INTO THE 40S MOST PLACES. COOLING WILL BE
BRIEF AS MID TO UPPER RIDGE BUILDS UP THE SOUTHEAST COAST THROUGH
SAT WITH H5 HEIGHTS RISING AND LOW LEVEL RETURN FLOW DEVELOPING.
OVERALL...LONG TERM PERIOD WILL START OUT COOL WITH OVERNIGHT LOWS
IN THE 30S POSSIBLY WED NIGHT BUT WILL END UP WITH SPRING LIKE
WEATHER BY THE END OF THE WEEKEND WITH SUNSHINE AND TEMPS IN THE
70S.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 17Z...VFR WITH VCSH. POTENTIAL FOR MVFR/IFR DUE TO LOWERED
CIGS AND REDUCED VISIBILITIES IN AREAS OF RAINFALL LATE OVERNIGHT
INTO EARLY MONDAY MORNING...IMPROVING TO VFR BY LATE MONDAY MORNING.
RAIN FROM EARLIER HAS FOR THE MOST PART TAPERED OFF...WITH CURRENT
SATELLITE DEPICTING A FEW BREAKS IN THE CLOUDS UPSTREAM. EXPECT VFR
TO PREVAIL...WITH SCATTERED TO MOSTLY CLOUDY SKIES AND SOUTHWEST
WINDS INCREASING TO AOB 15 KTS WITH GUSTS UP TO 25 KTS POSSIBLE. AS
THE DAY GOES ON...ANTICIPATE POSSIBILITY OF ISOLATED SHOWERS AND
EVEN AN ISOLATED THUNDERSTORM BEFORE TONIGHT. INTO THE OVERNIGHT
HOURS AND THROUGH MONDAY MORNING...ANTICIPATE SOUTHWEST WINDS AOB 8
KTS WITH SCATTERED SHOWERS AND THE POTENTIAL FOR MVFR/IFR DUE TO
LOWERED CIGS. ANY LINGERING RESTRICTIONS WILL GRADUALLY IMPROVE TO
VFR BY LATE MONDAY MORNING WITH WEST-NORTHWEST WINDS AOB 10 KTS.
EXTENDED OUTLOOK...SHOWERS AND ISOLATED THUNDERSTORMS POSSIBLE ON
MONDAY. OTHERWISE EXPECT VFR THROUGH EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 645 PM SUNDAY...WEAK RESULTANT/SEA BREEZE BOUNDARY NOTED BY
FINE LINE PUSHING INLAND FROM THE COAST WITH THE 0.5 DEGREE KLTX
88D. THIS HAS RESULTED WITH S TO SSW 15+ KT WINDS NEARSHORE. WITH
TIME THIS EVENING AND OVERNIGHT...WINDS WILL RE-ORIENT THEMSELVES
BACK TO A SYNOPTIC SW AT 15-25 KT. SSTS IN THE 50S PREVENTING THE
30KT OR STRONGER WIND GUSTS FROM REACHING THE OCEAN SFC ACROSS THE
ILM COASTAL WATERS. THE TIGHTENED SFC PG WILL CONTINUE TO SUPPORT
THE SUSTAINED 15-25 KT WIND SPEEDS ACROSS THE LOCAL WATERS
OVERNIGHT. SIGNIFICANT SEAS PRIMARILY DOMINATED BY THE 5 TO 6 SECOND
AVERAGE PERIOD WIND DRIVEN WAVES. OF NOTE...A 1 TO 2 FOOT ESE
GROUND SWELL AT 13+ SECOND PERIODS IS AFFECTING THE LOCAL WATERS.
OVERALL...LOOKING AT 3 TO 6 FOOT SIGNIFICANT SEAS WITH 7 FOOTERS
POSSIBLE ACROSS THE OUTER WATERS OFF CAPE FEAR.
PREVIOUS DISCUSSION..............................................
AS OF 3 PM SUNDAY...SMALL CRAFT ADVISORIES WILL REMAIN HOISTED
OVERNIGHT FOR ALL WATERS FOR GUSTS TO 25-30 KT AND GENERALLY 3-6
FOOT SEAS AND HIGHEST OFFSHORE. IT APPEARS THE PRESSURE GRADIENT
WILL LOOSEN INTO DAYBREAK MONDAY AS A WEAK COLD FRONT SAGS S INTO
THE FORECAST AREA FROM THE NW...ALLOWING WINDS TO MELLOW WELL
BELOW ADVISORY CRITERIA. SEAS MAY REQUIRE ANOTHER FEW HOURS TO
RECOVER AND THE ADVISORIES WILL RUN TO 9AM NC WATERS AND 6AM SC
WATERS DUE TO THE BUILDING TREND EXPECTED TONIGHT...HIGHEST SEAS
OUTER PORTION AROUND THE FRYING PAN SHOAL. SHORT-CRESTED WAVES
DUE TO SHORT WAVE PERIODS/INTERVALS WILL MAKE FOR STEEP WAVES
ADDING TO THE WIND HAZARD. ADDITIONALLY MARINERS SHOULD BE AWARE
THAT A FEW TSTMS WILL BE FAVORED OVER THE OUTER WATERS AND WEST
WALL OF THE GULF STREAM OVERNIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...SOUTHWEST FLOW MON BECOMES WEST-NORTHWEST AS
COLD FRONT MOVES SOUTH ACROSS THE WATERS. FRONT WILL BE SLOW TO MOVE
WITH OFFSHORE FLOW NOT DEVELOPING UNTIL MON NIGHT. SPEEDS WILL BE
10 TO 15 KT INTO MON AFTERNOON BUT DROP AS BOUNDARY REACHES THE
WATERS. WEAK GRADIENT BEHIND THE FRONT AND LACK OF SIGNIFICANT
COLD ADVECTION KEEP WINDS 10 KT OR LESS INTO TUE. A SECOND FRONT
WILL PUSH SOUTH TUE MORNING...REINFORCING NORTHERLY FLOW. THIS
FRONT ALSO LACKS A SIGNIFICANT COLD SURGE WITH PROLONGED STEADY
COLD ADVECTION BEHIND IT INSTEAD. SPEEDS WILL NOT INCREASE
APPRECIABLY BEHIND THE FRONT. WINDS MAY OCCASIONALLY EXCEED 10 KT
BUT OVERALL 10 KT SHOULD BE SUFFICIENT. REDUCTION IN WINDS THROUGH
THE PERIOD WILL TRANSLATE TO SEAS FALLING FROM 3 TO 5 FT AT THE
START OF THE PERIOD TO 2 TO 4 FT MON NIGHT AND 2 TO 3 FT TUE/TUE
NIGHT.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 3 PM SUNDAY...WINDS WILL VEER AROUND FROM THE N TO THE NE AS
HIGH PRESSURE BUILDS INTO THE WATERS WED. IN GENERAL EXPECT WINDS 15
KTS OR LESS AND SEAS 3 FT OR LESS THROUGH WED.
BY WED NIGHT INTO THURS HIGH PRESSURE WILL SHIFT OFF SHORE AS LOW
PRESSURE DEEPENS OVER THE GULF COAST AND THEN MOVES UP THROUGH THE
SOUTHEAST THURS NIGHT INTO FRI. NORTHEAST WINDS WILL INCREASE AND
VEER AROUND FROM THE NE TO E WED NIGHT THROUGH THURS AS GRADIENT
TIGHTENS BETWEEN THESE TWO SYSTEMS. WINDS WILL EVENTUALLY SHIFT
AROUND BECOMING INCREASINGLY ON SHORE THURS NIGHT. SEAS SHOULD REACH
UP INTO SCA THRESHOLDS BY THURS AFTN WITH INCREASING ON SHORE WINDS
UP TO 25 TO 30 KTS DRIVING SEAS UP TO 4 TO 6 FT NEAR SHORE BY THURS
EVENING AND UP TO 9 TO 11 FT OVER THE OUTER WATERS THROUGH THURS
NIGHT.
WINDS WILL SHIFT AROUND TO THE W-NW THROUGH FRI ON THE BACK END OF
THE LOW PRESSURE SYSTEM AS IT LIFTS OFF TO THE NORTHEAST. THIS OFF
SHORE FLOW WILL HELP TO LOWER SEAS NEAR SHORE BUT CAA AND TIGHTENED
GRADIENT FLOW WILL KEEP SEAS UP NEAR SCA IN OUTER WATERS THROUGH FRI
EVENING. BY SAT MORNING WINDS WILL DIMINISH TO 15 KTS OR LESS AND
SEAS WILL BE DOWN TO 2 TO 4 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR AMZ254-256.
SMALL CRAFT ADVISORY UNTIL 9 AM EDT MONDAY FOR AMZ250-252.
&&
$$
SYNOPSIS...
NEAR TERM...DCH/MJC
SHORT TERM...III
LONG TERM...RGZ
AVIATION...BJR
MARINE...
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
847 PM CDT SUN MAR 31 2013
.DISCUSSION...
MADE A FEW MINOR TWEAKS TO TEMPERATURES BUT NO REALLY MAJOR
CHANGES FOR THE EVENING UPDATE. HIGH PRESSURE CONTINUES TO EXTEND
FROM SASKATCHEWAN INTO THE DAKOTAS. STRATOCU HAS MOSTLY DISSIPATED
AFTER SUNSET AS EXPECT...ALTHOUGH SAT LOOP SHOWS A FEW LINGERING
CLOUDS OVER THE EASTERN CWA. CONTINUE TO SEEM ON TRACK FOR A CLEAR
AND COLD NIGHT. MOST MOS GUIDANCE KEEPS US IN THE POSITIVE
DIGITS...BUT THE GEM AND RAP DROP US TO NEAR -10 IN SOME SPOTS.
THINK THIS IS OVERDONE GIVEN THE DEW POINTS UPSTREAM...BUT EVEN
THE SREF HAS SOME LOCATIONS DROPPING TO AROUND 5 BELOW ZERO.
LEANED A BIT ON THE COLDER SIDE AND DROPPED LOWS ANOTHER DEGREE OR
SO. THINK THAT WINDS WILL STAY UP AROUND 5 KTS AND FOG WILL STAY
WEST OF THE AREA...BUT WILL KEEP AN EYE ON ANYTHING DEVELOPING.
&&
.AVIATION...
VFR CONDITIONS WILL RETURN TO ALL THE TAF SITES IN THE NEXT HOUR
OR SO AS STRATOCU CONTINUES TO DISSIPATE. CLEAR SKIES AND
DECREASING NORTHWEST WINDS TO AROUND 10 KTS WILL BE FOUND ACROSS
MOST OF THE AREA. SOME STRATOCU REDEVELOPMENT TOMORROW AFTERNOON
WILL BE POSSIBLE TOWARDS THE END OF THE PERIOD.
&&
.PREV DISCUSSION... /ISSUED 238 PM CDT SUN MAR 31 2013/
SHORT TERM...
MAIN FORECAST CHALLENGE IN THE SHORT TERM WILL BE TEMPS. MODELS
IN FAIR AGREEMENT ON DETAILS SO WILL USE A MODEL BLEND.
TONIGHT...QUITE A BIT OF STRATOCU DEVELOPED ALONG AND EAST OF THE
RED RIVER VALLEY BY LATE MORNING AND EARLY AFTERNOON. EXPECT MOST
OF THIS TO FADE AWAY WITH LOSS OF DAYTIME HEATING LEAVING MOST OF
THE AREA MOSTLY CLEAR TONIGHT. NORTH/NORTHWEST WINDS ARE STILL
FAIRLY BRISK AND WOULD ALSO EXPECT THESE TO DROP OFF SLOWLY THIS
EVENING. THIS SETS THE STAGE FOR A COLD NIGHT AGAIN. UNDER SIMILAR
CIRCUMSTANCES LAST WEEK THE TOWNER/BENSON COUNTY AREA DROPPED DOWN
INTO THE FIVE BELOW TO TEN BELOW ZERO RANGE. HOWEVER IT IS NOW
ALMOST APRIL SO IT DOES NOT SEEM LOGICAL THAT LOWS CAN STILL DROP
THAT LOW. EVEN SO WILL UNDERCUT MOST GUIDANCE AND GO WITH SUBZERO
TEMPS AROUND THE KDVL REGION. THIS AREA HAS ALSO EXPERIENCED QUITE
A BIT OF FOG RECENTLY BUT HAVE MY DOUBTS ABOUT TONIGHT. STIFF
NORTHWEST FLOW AND LITTLE MELTING TODAY ARE NOT GREAT CONTRIBUTORS
TO FOG SO WILL LET THE NEXT SHIFT TAKE ANOTHER LOOK AT THAT.
MON-WED...SHOULD BASICALLY BE LOOKING AT CONTINUED SFC HIGH
PRESSURE THROUGHOUT THE MON-TUE NIGHT TIME FRAME WITH NO PCPN
EXPECTED. SHOULD SEE A LITTLE BIT OF WARMING FOR DAYTIME HIGHS
FROM MON INTO TUE. MODELS ADVERTISING THE BEST CHANCE OF WARMER
TEMPS FOR WED WITH MODELS SHOWING 850MB TEMPS RISING BACK ABOVE
ZERO. NEXT SHOT OF PCPN COMES ON WED AS THE MAIN SFC LOW TRACKS
ACROSS SOUTHERN CANADA. FRONTAL BOUNDARY DOES PUSH ACROSS THE AREA
WITH SLIGHTLY BETTER CHANCES FOR PCPN BEING ALONG AND NORTH OF
HIGHWAY 200. AT THIS POINT PCPN TYPE LOOKS TO BE RAIN BUT COULD BE
A MIX IN THE MORNING.
LONG TERM (WED NIGHT-SUN)...
A POTENTIALLY ACTIVE PATTERN MAY DEVELOP BY NEXT FRIDAY INTO SUNDAY.
TEMPS SHOULD REMAIN BELOW NORMAL WITH THE COLDEST DAY ON THU WITH
HIGH PRESSURE. ON FRI...A HYBRID SYSTEM SHOULD SPREAD MOSTLY SNOW
INTO THE SOUTHERN 2/3 OF THE AREA...WITH PERHAPS SOME RAIN MIXING
IN. THE GFS AND LATEST INDICATIONS OF THE OTHER DETERMINISTIC MODELS
WOULD INDICATE ACCUMULATING SNOW IS POSSIBLE FRIDAY NIGHT INTO SAT.
THIS COULD DELAY THE LARGE SCALE SPRING MELTING A BIT FURTHER IF
LATEST TRENDS CONTINUE...ALTHOUGH THERE ARE DIFFERENCES AFTER THU SO
STAY TUNED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
JR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
359 PM EDT SAT MAR 30 2013
.SYNOPSIS...
HIGH PRESSURE WILL MOVE EAST OF THE REGION TONIGHT. A TROUGH OF
LOW PRESSURE WILL MOVE THROUGH THE OHIO VALLEY ON
SUNDAY...PROVIDING A CHANCE OF RAIN. A COLD FRONT WILL THEN MOVE
THROUGH SUNDAY NIGHT...PROVIDING COOLER TEMPERATURES FOR THE FIRST
PART OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A RELATIVELY DRY SURFACE AIR MASS HAS INHIBITED CUMULUS
DEVELOPMENT TODAY. A LOOK AT SURFACE OBS SHOWS THAT DEWPOINTS OVER
THE REGION REMAIN IN THE 20S TO LOWER 30S...WITH DEWPOINTS OVER 40
SOUTH AND WEST OF A BOUNDARY THAT CUTS THROUGH THE FAR
SOUTHWESTERN TIP OF INDIANA. AT THE SAME TIME...HIGH CLOUDS HAVE
BEEN INCREASING...AND MOISTURE IS EXPECTED TO CONTINUE TO LOWER
THROUGH THE NEAR TERM OF THE FORECAST.
THE FOCUS FOR PRECIPITATION WILL BE ON A SHORTWAVE CURRENTLY
MOVING ACROSS MISSOURI AND INTO ILLINOIS. THERE WILL BE EFFECTS ON
THE CWA BEFORE MORNING...BUT FOR THE SAKE OF EASE...THIS FEATURE
WILL BE DISCUSSED IN THE SHORT TERM SECTION OF THE AFD.
WITH CLOUDS MOVING IN...AND WARM ADVECTION AHEAD OF THE
SHORTWAVE...OVERNIGHT TEMPS WILL BE AT LEAST TEN DEGREES WARMER
THAN LAST NIGHT. MIN TEMP VALUES ARE NEAR OR SLIGHTLY WARMER THAN
THE MODEL BLEND...WHICH EXHIBITS A RELATIVELY SMALL
SPREAD. HOWEVER...THE FORECAST IS NOT AS WARM AS THE RAP13.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
A SHORTWAVE CURRENTLY MOVING THROUGH THE MIDDLE MISSISSIPPI VALLEY
WILL BEGIN TO AFFECT THE WESTERN CWA BY 06Z. THE AMPLITUDE OF THIS
SHORTWAVE IS NOT ESPECIALLY STRONG...AND IT IS SOMEWHAT TOUGH TO
DISCERN WHEN LOOKING ONLY AT 500MB HEIGHT CONTOURS. WITH THE DRY
AIR IN PLACE OVER MUCH OF THE OHIO VALLEY RIGHT NOW...IT IS NOT
ENTIRELY SURPRISING THAT THE TREND HAS BEEN TOWARD SLIGHTLY DRIER
SOLUTIONS FOR SUNDAY MORNING. THE SIGNAL FROM THE HIGH-
RESOLUTION OUTPUT IS CONFLICTING...WITH THE 12Z SPC-WRF INDICATING
ONLY SCATTERED SHOWERS (AND SOME BIG DRY PATCHES)...AND THE MOST
RECENT HRRR RUN SHOWING A SOLID AREA OF PRECIPITATION FOR THE
SOUTHERN HALF OF THE CWA. TIMING WAS ADJUSTED ON THE POPS...WITH A
SLIGHTLY ADJUSTMENT DOWNWARD IN VALUE AS WELL...AND NO HIGHER THAN
LIKELY FOR THE SOUTHERN CWA.
AN ASPECT OF THE SYSTEM THAT IS AGREED UPON FROM ALL SOURCES IS A
SPLIT IN THE PRECIPITATION BETWEEN A SOUTHERN AREA OF
PRECIPITATION (PRIMARILY AFFECTING KENTUCKY AND TENNESSEE) AND
WITH A NORTHERN STREAM SYSTEM MOVING THROUGH MICHIGAN. THE
NORTHERN SYSTEM WILL LAG BEHIND THE SOUTHERN SYSTEM BY SEVERAL
HOURS...BUT THIS WILL LIKELY ACT TO INITIATE MORE SHOWERS OVER THE
EASTERN CWA THROUGH MID-AFTERNOON. SPC SREF PARAMETERS INDICATE
THAT SOME WEAK INSTABILITY COULD BUILD IN TO THE SOUTHEASTERN AND
EASTERN CWA DURING THIS TIME FRAME...SO THUNDER WAS KEPT IN THE
FORECAST.
BY SUNDAY NIGHT...A COLD FRONT WILL BE MOVING INTO THE NORTHERN
PORTIONS OF THE CWA. WHILE THE COLD ADVECTION IS NOTABLE BEHIND
THE FRONT...THE SURFACE PRESSURE PATTERN IS WEAK...AND FORCING
IS ALMOST NON-EXISTENT. AS A RESULT OF THIS...THE FRONT SHOULD
PASS THROUGH DRY. HOWEVER...IN A REGION OF COLD ADVECTION BEHIND
THE FRONT...A WEAK RIPPLE IN THE FLOW (ROUNDING THE SOUTHWESTERN
EDGE OF THE LARGE UPPER TROUGH) WILL PASS INTO THE CWA. THIS
FEATURE MAY BRING A BAND OF LIGHT PRECIPITATION DURING THE FIRST
TWO-THIRDS OF MONDAY. HOWEVER...THIS HAS BEEN MODELED DRIER ON THE
LAST SET OF RUNS...SO POPS HAVE BEEN LIMITED TO 20 PERCENT.
TEMPERATURES SUPPORT A MIX OF SNOW AND RAIN (WITH GENERALLY SNOW
IN THE NORTH AND GENERALLY RAIN IN THE SOUTH)...BUT AS QPF IS
EXTREMELY LIGHT...THE DAY SHOULD NOT BE A STRIKEOUT.
WITH THE ONLY SIGNIFICANT TEMPERATURE ADVECTION OCCURRING SUNDAY
NIGHT WITH THE COLD FRONT...TEMPS SHOULD REMAIN GENERALLY DIURNAL
THROUGH THE PERIOD. AFTER A DAY OF COLD ADVECTION AND AS SKIES
CLEAR OUT MONDAY NIGHT...TEMPS APPEAR TO BE SET TO DROP INTO THE
20S...10-15 DEGREES BELOW NORMAL FOR EARLY APRIL.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
DEEP MID LVL TROUGH WILL PROGRESS EASTWARD TUESDAY INTO WEDNESDAY
...ALLOWING SFC HIGH PRESSURE TO SETTLE INTO THE GREAT LAKES AND
OHIO VALLEY. ON TUESDAY...THERE COULD BE SOME DIURNALLY DRIVEN
CUMULUS BUT IT LOOKS LIKE MOST OF THE REGION WILL BE MOSTLY SUNNY. IT
SHOULD BE MOSTLY CLEAR TUESDAY NIGHT AND MOSTLY SUNNY ON WEDNESDAY.
COLDEST TEMPERATURES ARE EXPECTED TUESDAY INTO TUESDAY NIGHT. HIGHS
ON TUESDAY WILL RANGE FROM THE UPPER 30S NORTH TO THE MID 40S SOUTH.
LOWS TUESDAY NIGHT WILL DROP INTO THE LOWER AND MID 20S. SOME
MODIFICATION IS EXPECTED ON WEDNESDAY BUT TEMPERATURES WILL REMAIN
BELOW NORMAL FOR EARLY APRIL. HIGHS WILL RANGE FROM THE LOWER 40S NE
TO THE UPPER 40S SOUTHWEST.
UPR LVL FLOW WILL TRANSITION TO A MORE ZONAL PATTERN LATE IN THE
WEEK. THERE WILL BE A SPLIT FLOW BETWEEN NRN STREAM ENERGY AND SRN
STREAM ENERGY. MODELS HAVE BEEN OSCILLATING ON HOW THE NRN STREAM
ENERGY WILL INTERACT WITH THE SRN STREAM ENERGY. FOR NOW...HAVE KEPT
AN UPR LVL LOW AND PCPN WITH THE SRN STREAM ENERGY TO OUR SOUTH AND
EAST THURSDAY INTO FRIDAY WHILE A WEAK COLD FRONT DROPS SOUTHEAST
THROUGH THE REGION THURSDAY NIGHT INTO FRIDAY. TEMPERATURES WILL
CONTINUE TO MODERATE WITH HIGHS IN THE 50S ON THURSDAY AND 50S TO
NEAR 60 ON FRIDAY.
FOR FRIDAY NIGHT INTO SATURDAY...SURFACE HIGH PRESSURE WILL PUSH
INTO THE REGION AND WILL EVENTUALLY MOVE EAST. DRY WEATHER WITH
TEMPERATURES NEAR SEASONAL NORMALS ARE EXPECTED.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
LOCATIONS OF GREATEST CONFIDENCE FOR SHRA WILL BE KCVG/KLUK WITH
BEING ON THE NORTHERN FRINGE OF TONIGHTS SHORTWAVE PUSHING ACROSS
THE TN/CUMBERLAND VALLEYS. CARRIED THUNDER IN THE 10-13Z
TIMEFRAME...THOUGH CONFIDENCE NOT WITH THE LATEST MODEL RUNS.
WOULD STILL EXPECT PERIOD OF MVFR CIGS MAINLY AT KDAY/KCVG/KLUK
AND POSSIBLY KILN CLOSER TO THE SOUTHERN STREAM S/WV. SECONDARY
WAVE SWINGING ACROSS NORTHERN AREA MAY NOT HAVE AS MUCH OF AN
EFFECT ON TAF SITES AS CURRENT MODELS PLACE BEST CHANCE FOR
PRECIPITATION FURTHER NORTH THAN TAF SITES. AS A RESULT...MVFR
LIMITED TO MAINLY THE SOUTHERN SYSTEM FROM THE 10Z-15Z
TIMEFRAME...WITH WESTERLY WINDS BECOMING A LITTLE MORE GUSTY AFTER
20Z.
OUTLOOK...MVFR CONDITIONS AGAIN ON MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...HICKMAN
AVIATION...JDR
AREA FORECAST DISCUSSION
NWS TULSA OK
1225 PM CDT SAT MAR 30 2013
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
MORNING ROUND OF SHOWERS AND STORMS EXITING THIS MORNING WITH
GENERALLY VFR CONDITIONS IN ITS WAKE...BUT SOME MVFR CEILINGS MAY
LINGER AN HOUR OR SO OVER WESTERN ARKANSAS. SOME ADDITIONAL
THUNDERSTORMS MAY DEVELOP LATE IN THE AFTERNOON TOWARD 00Z WITH AN
INCREASE TONIGHT AS A COLD FRONT PUSHES THROUGH 06-12Z. WHILE
PREVAILING CONDITIONS SHOULD REMAIN JUST ABOVE VFR LEVELS...A
PERIOD OF MVFR OR EVEN IFR CONDITIONS WITHIN THAT TIME FRAME IS
LIKELY AS THE FRONT PASSES. CONDITIONS WILL IMPROVE FROM THE NORTH
AFTER 12Z.
&&
.PREV DISCUSSION... /ISSUED 1026 AM CDT SAT MAR 30 2013/
DISCUSSION...
SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE ACROSS EAST CENTRAL OK
AND NORTHWEST AR THIS MORNING BUT CONTINUE TO DECREASE IN
INTENSITY AS THEY SHIFT SOUTHEAST. EXPECT THIS ROUND TO MOVE OUT
OF THE FORECAST AREA AROUND 19-20Z WITH ENOUGH BREAKS IN CLOUDS TO
SEND TEMPS WELL INTO 70S ACROSS MUCH OF EASTERN OK...AND REMAINING
A BIT COOLER IN FAR EASTERN AREAS. RE-DEVELOPMENT OF STORMS ALONG
ANY BOUNDARIES THIS AFTERNOON APPEARS QUESTIONABLE...THOUGH
CERTAINLY NOT A ZERO CHANCE IN UNSTABLE AND WEAKLY CAPPED
ENVIRONMENT. HAVE UPDATED POPS BASED ON RADAR TRENDS FOR THE
MORNING AND HAVE REDUCED THEM SOME FOR THE AFTERNOON ACROSS
WESTERN AREAS. ALSO KNOCKED A FEW DEGREES OFF FORECAST HIGHS IN
FAR NW ARKANSAS.
PREV DISCUSSION... /ISSUED 623 AM CDT SAT MAR 30 2013/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VARIABLE SKY CONDITIONS WILL PERSIST THROUGH THE MORNING
HOURS...WITH AREAS OF MVFR/IFR CIGS MAINLY ACROSS SOUTHEAST
OK AND WEST CENTRAL AR. LOCALIZED LOWER CIGS/VSBYS WILL
OCCUR WITH SHOWERS/THUNDERSTORMS THROUGH THE MORNING HOURS.
SOME IMPROVEMENT IS EXPECTED INTO THE AFTERNOON...WITH
AREAS OF SHOWERS/THUNDERSTORMS DEVELOPING AGAIN BY LATE
AFTERNOON OR EARLY EVENING.
PREV DISCUSSION... /ISSUED 457 AM CDT SAT MAR 30 2013/
DISCUSSION...
WAVE TRAIN ROLLING ALONG IN NORTHWEST FLOW HAULING
CLUSTERS OF SHOWERS AND THUNDERSTORMS THIS MORNING.
SOME OF THE STRONGER THUNDERSTORMS PROVED EFFICIENT
HAIL PRODUCERS OVERNIGHT.
IN THE SHORT TERM FOLLOWED HRRR MODEL WHICH HAS BEEN
GOOD LAST SIX HOURS WITH CONVECTIVE ACTION. BULK OF
CURRENT PRECIP EAST OF NORTHWEST AR ZONES AROUND 18Z.
QUESTION THEN BECOMES WHAT BOUNDARIES ARE LEFT BEHIND
TO FIRE LATE AFTERNOON..OR EVENING. TEMPERATURES INTO
THE MID 70S THIS AFTERNOON..IN ADVANCE OF A WEAK COOL
FRONTAL BOUNDARY SAGGING INTO THE FORECAST AREA WILL
LIKELY IGNITE ANOTHER ROUND OF THUNDER. CAPE VALUES
IN THE 2000 J/KG NEIGHBORHOOD AND SUFFICIENT SHEAR
WILL BE CAPABLE OF LARGE HAIL PRODUCTION.
CONVECTION MIGRATING SOUTHEAST OVERNIGHT LEAVING MOST
AREAS NORTH OF INTERSTATE 40 WITH A DRY WARM EASTER.
SHOWERS THUNDER MOST LIKELY NEAR OR SOUTH OF THE RED
RIVER.
NEXT WAVE AND REAL COLD FRONT ARRIVE SOMETIME MONDAY.
WRF VERY FAST AND THE OUTLIER IN BRINGING IN THE COLD
AIR COMPARED TO MOST OF THE OTHER MODELS. RESULTING
WRF MOS BASED MAX TEMPS SOME 15 TO 20 DEGREES COLDER
FOR NORTHERN LOCATIONS. USED FOUR MODEL MAX TEMP.
MODEL DIFFERENCES CONTINUE TO PLAGUE THE MIDWEEK TIME
PERIOD. ECMWF CONSISTENT WITH ITSELF BRINGING AN UPPER
LOW DIRECTLY OVER FORECAST AREA. MEANWHILE GFS WEAKER
DRIER... MORE PROGRESSIVE WITH THE FEATURE. ECMWF TOO
GOOD TO TOTALLY IGNORE..CHANCE POPS MIDWEEK.
GW
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...99
LONG TERM....99
AVIATION...14
AREA FORECAST DISCUSSION
NWS TULSA OK
1026 AM CDT SAT MAR 30 2013
.DISCUSSION...
SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE ACROSS EAST CENTRAL OK
AND NORTHWEST AR THIS MORNING BUT CONTINUE TO DECREASE IN
INTENSITY AS THEY SHIFT SOUTHEAST. EXPECT THIS ROUND TO MOVE OUT
OF THE FORECAST AREA AROUND 19-20Z WITH ENOUGH BREAKS IN CLOUDS TO
SEND TEMPS WELL INTO 70S ACROSS MUCH OF EASTERN OK...AND REMAINING
A BIT COOLER IN FAR EASTERN AREAS. RE-DEVELOPMENT OF STORMS ALONG
ANY BOUNDARIES THIS AFTERNOON APPEARS QUESTIONABLE...THOUGH
CERTAINLY NOT A ZERO CHANCE IN UNSTABLE AND WEAKLY CAPPED
ENVIRONMENT. HAVE UPDATED POPS BASED ON RADAR TRENDS FOR THE
MORNING AND HAVE REDUCED THEM SOME FOR THE AFTERNOON ACROSS
WESTERN AREAS. ALSO KNOCKED A FEW DEGREES OFF FORECAST HIGHS IN
FAR NW ARKANSAS.
&&
.PREV DISCUSSION... /ISSUED 623 AM CDT SAT MAR 30 2013/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VARIABLE SKY CONDITIONS WILL PERSIST THROUGH THE MORNING
HOURS...WITH AREAS OF MVFR/IFR CIGS MAINLY ACROSS SOUTHEAST
OK AND WEST CENTRAL AR. LOCALIZED LOWER CIGS/VSBYS WILL
OCCUR WITH SHOWERS/THUNDERSTORMS THROUGH THE MORNING HOURS.
SOME IMPROVEMENT IS EXPECTED INTO THE AFTERNOON...WITH
AREAS OF SHOWERS/THUNDERSTORMS DEVELOPING AGAIN BY LATE
AFTERNOON OR EARLY EVENING.
PREV DISCUSSION... /ISSUED 457 AM CDT SAT MAR 30 2013/
DISCUSSION...
WAVE TRAIN ROLLING ALONG IN NORTHWEST FLOW HAULING
CLUSTERS OF SHOWERS AND THUNDERSTORMS THIS MORNING.
SOME OF THE STRONGER THUNDERSTORMS PROVED EFFICIENT
HAIL PRODUCERS OVERNIGHT.
IN THE SHORT TERM FOLLOWED HRRR MODEL WHICH HAS BEEN
GOOD LAST SIX HOURS WITH CONVECTIVE ACTION. BULK OF
CURRENT PRECIP EAST OF NORTHWEST AR ZONES AROUND 18Z.
QUESTION THEN BECOMES WHAT BOUNDARIES ARE LEFT BEHIND
TO FIRE LATE AFTERNOON..OR EVENING. TEMPERATURES INTO
THE MID 70S THIS AFTERNOON..IN ADVANCE OF A WEAK COOL
FRONTAL BOUNDARY SAGGING INTO THE FORECAST AREA WILL
LIKELY IGNITE ANOTHER ROUND OF THUNDER. CAPE VALUES
IN THE 2000 J/KG NEIGHBORHOOD AND SUFFICIENT SHEAR
WILL BE CAPABLE OF LARGE HAIL PRODUCTION.
CONVECTION MIGRATING SOUTHEAST OVERNIGHT LEAVING MOST
AREAS NORTH OF INTERSTATE 40 WITH A DRY WARM EASTER.
SHOWERS THUNDER MOST LIKELY NEAR OR SOUTH OF THE RED
RIVER.
NEXT WAVE AND REAL COLD FRONT ARRIVE SOMETIME MONDAY.
WRF VERY FAST AND THE OUTLIER IN BRINGING IN THE COLD
AIR COMPARED TO MOST OF THE OTHER MODELS. RESULTING
WRF MOS BASED MAX TEMPS SOME 15 TO 20 DEGREES COLDER
FOR NORTHERN LOCATIONS. USED FOUR MODEL MAX TEMP.
MODEL DIFFERENCES CONTINUE TO PLAGUE THE MIDWEEK TIME
PERIOD. ECMWF CONSISTENT WITH ITSELF BRINGING AN UPPER
LOW DIRECTLY OVER FORECAST AREA. MEANWHILE GFS WEAKER
DRIER... MORE PROGRESSIVE WITH THE FEATURE. ECMWF TOO
GOOD TO TOTALLY IGNORE..CHANCE POPS MIDWEEK.
GW
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 77 51 73 43 / 90 60 10 10
FSM 73 56 74 48 / 70 60 30 10
MLC 75 55 73 48 / 70 60 30 10
BVO 76 46 72 40 / 40 50 10 10
FYV 67 51 70 42 / 100 70 20 0
BYV 65 49 69 41 / 90 70 10 0
MKO 75 54 72 46 / 60 60 20 10
MIO 71 47 71 42 / 90 60 0 10
F10 76 54 72 47 / 50 60 20 10
HHW 74 57 72 53 / 50 60 60 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...14
AREA FORECAST DISCUSSION
NWS TULSA OK
623 AM CDT SAT MAR 30 2013
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VARIABLE SKY CONDITIONS WILL PERSIST THROUGH THE MORNING
HOURS...WITH AREAS OF MVFR/IFR CIGS MAINLY ACROSS SOUTHEAST
OK AND WEST CENTRAL AR. LOCALIZED LOWER CIGS/VSBYS WILL
OCCUR WITH SHOWERS/THUNDERSTORMS THROUGH THE MORNING HOURS.
SOME IMPROVEMENT IS EXPECTED INTO THE AFTERNOON...WITH
AREAS OF SHOWERS/THUNDERSTORMS DEVELOPING AGAIN BY LATE
AFTERNOON OR EARLY EVENING.
&&
.PREV DISCUSSION... /ISSUED 457 AM CDT SAT MAR 30 2013/
DISCUSSION...
WAVE TRAIN ROLLING ALONG IN NORTHWEST FLOW HAULING
CLUSTERS OF SHOWERS AND THUNDERSTORMS THIS MORNING.
SOME OF THE STRONGER THUNDERSTORMS PROVED EFFICIENT
HAIL PRODUCERS OVERNIGHT.
IN THE SHORT TERM FOLLOWED HRRR MODEL WHICH HAS BEEN
GOOD LAST SIX HOURS WITH CONVECTIVE ACTION. BULK OF
CURRENT PRECIP EAST OF NORTHWEST AR ZONES AROUND 18Z.
QUESTION THEN BECOMES WHAT BOUNDARIES ARE LEFT BEHIND
TO FIRE LATE AFTERNOON..OR EVENING. TEMPERATURES INTO
THE MID 70S THIS AFTERNOON..IN ADVANCE OF A WEAK COOL
FRONTAL BOUNDARY SAGGING INTO THE FORECAST AREA WILL
LIKELY IGNITE ANOTHER ROUND OF THUNDER. CAPE VALUES
IN THE 2000 J/KG NEIGHBORHOOD AND SUFFICIENT SHEAR
WILL BE CAPABLE OF LARGE HAIL PRODUCTION.
CONVECTION MIGRATING SOUTHEAST OVERNIGHT LEAVING MOST
AREAS NORTH OF INTERSTATE 40 WITH A DRY WARM EASTER.
SHOWERS THUNDER MOST LIKELY NEAR OR SOUTH OF THE RED
RIVER.
NEXT WAVE AND REAL COLD FRONT ARRIVE SOMETIME MONDAY.
WRF VERY FAST AND THE OUTLIER IN BRINGING IN THE COLD
AIR COMPARED TO MOST OF THE OTHER MODELS. RESULTING
WRF MOS BASED MAX TEMPS SOME 15 TO 20 DEGREES COLDER
FOR NORTHERN LOCATIONS. USED FOUR MODEL MAX TEMP.
MODEL DIFFERENCES CONTINUE TO PLAGUE THE MIDWEEK TIME
PERIOD. ECMWF CONSISTENT WITH ITSELF BRINGING AN UPPER
LOW DIRECTLY OVER FORECAST AREA. MEANWHILE GFS WEAKER
DRIER... MORE PROGRESSIVE WITH THE FEATURE. ECMWF TOO
GOOD TO TOTALLY IGNORE..CHANCE POPS MIDWEEK.
GW
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 77 51 73 43 / 50 60 10 10
FSM 73 56 74 48 / 80 60 30 10
MLC 75 55 73 48 / 50 60 30 10
BVO 76 46 72 40 / 40 50 10 10
FYV 69 51 70 42 / 90 70 20 0
BYV 67 49 69 41 / 90 70 10 0
MKO 75 54 72 46 / 60 60 20 10
MIO 71 47 71 42 / 70 60 0 10
F10 76 54 72 47 / 50 60 20 10
HHW 74 57 72 53 / 60 60 60 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...18
AREA FORECAST DISCUSSION
NWS TULSA OK
457 AM CDT SAT MAR 30 2013
.DISCUSSION...
WAVE TRAIN ROLLING ALONG IN NORTHWEST FLOW HAULING
CLUSTERS OF SHOWERS AND THUNDERSTORMS THIS MORNING.
SOME OF THE STRONGER THUNDERSTORMS PROVED EFFICIENT
HAIL PRODUCERS OVERNIGHT.
IN THE SHORT TERM FOLLOWED HRRR MODEL WHICH HAS BEEN
GOOD LAST SIX HOURS WITH CONVECTIVE ACTION. BULK OF
CURRENT PRECIP EAST OF NORTHWEST AR ZONES AROUND 18Z.
QUESTION THEN BECOMES WHAT BOUNDARIES ARE LEFT BEHIND
TO FIRE LATE AFTERNOON..OR EVENING. TEMPERATURES INTO
THE MID 70S THIS AFTERNOON..IN ADVANCE OF A WEAK COOL
FRONTAL BOUNDARY SAGGING INTO THE FORECAST AREA WILL
LIKELY IGNITE ANOTHER ROUND OF THUNDER. CAPE VALUES
IN THE 2000 J/KG NEIGHBORHOOD AND SUFFICIENT SHEAR
WILL BE CAPABLE OF LARGE HAIL PRODUCTION.
CONVECTION MIGRATING SOUTHEAST OVERNIGHT LEAVING MOST
AREAS NORTH OF INTERSTATE 40 WITH A DRY WARM EASTER.
SHOWERS THUNDER MOST LIKELY NEAR OR SOUTH OF THE RED
RIVER.
NEXT WAVE AND REAL COLD FRONT ARRIVE SOMETIME MONDAY.
WRF VERY FAST AND THE OUTLIER IN BRINGING IN THE COLD
AIR COMPARED TO MOST OF THE OTHER MODELS. RESULTING
WRF MOS BASED MAX TEMPS SOME 15 TO 20 DEGREES COLDER
FOR NORTHERN LOCATIONS. USED FOUR MODEL MAX TEMP.
MODEL DIFFERENCES CONTINUE TO PLAGUE THE MIDWEEK TIME
PERIOD. ECMWF CONSISTENT WITH ITSELF BRINGING AN UPPER
LOW DIRECTLY OVER FORECAST AREA. MEANWHILE GFS WEAKER
DRIER... MORE PROGRESSIVE WITH THE FEATURE. ECMWF TOO
GOOD TO TOTALLY IGNORE..CHANCE POPS MIDWEEK.
GW
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 77 51 73 43 / 50 60 10 10
FSM 73 56 74 48 / 80 60 30 10
MLC 75 55 73 48 / 50 60 30 10
BVO 76 46 72 40 / 40 50 10 10
FYV 69 51 70 42 / 90 70 20 0
BYV 67 49 69 41 / 90 70 10 0
MKO 75 54 72 46 / 60 60 20 10
MIO 71 47 71 42 / 70 60 0 10
F10 76 54 72 47 / 50 60 20 10
HHW 74 57 72 53 / 60 60 60 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...18
LONG TERM....21
AREA FORECAST DISCUSSION...CORRECTED
NWS MEDFORD OR
256 PM PDT SAT MAR 30 2013
.SHORT TERM...A CUTOFF LOW OFF THE CENTRAL CALIFORNIA COAST
REMAINS THE MAIN WEATHER MAKER FOR THE NEXT COUPLE DAYS. THIS LOW
IS MOVING TOWARDS REGION TODAY AND IS FORECAST TO MOVE INLAND
SUNDAY AND MONDAY. THEN A HIGH PRESSURE RIDGE WILL BRING WARM AND
DRY CONDITIONS BEGINNING TUESDAY.
AHEAD OF THIS LOW...MOISTURE AND INSTABILITY ARE INCREASING TODAY.
ISOLATED THUNDERSTORMS HAVE DEVELOPED EARLY THIS AFTERNOON TO THE
SOUTH IN LASSEN AND SHASTA COUNTY WHERE THE BEST LIFT IS INDICATED
IN THE MESO ANALYSIS AND RAP FORECAST. ALSO MESO ANALYSIS SHOWS
PRECIPITABLE WATER VALUES OF 0.8 INCHES ALONG THE NORTHERN
CALIFORNIA COAST. INLAND PW AMOUNTS RANGE FROM 0.4 TO 0.7 INCHES AND
WILL INCREASE LATE THIS AFTERNOON AND THIS EVENING AS MOISTURE
MOVES UP FROM THE SOUTH AND SOUTHEAST INTO THE AREA. DAYTIME
HEATING WILL RESULT IN SURFACE BASED INSTABILITY AND MODELS SHOW
INCREASING LIFT OVER CENTRAL PORTIONS AND SOUTHERN PORTIONS OF
THE AREA IN THE LATE AFTERNOON AND EVENING. ALSO MODELS SHOW
THAT CAPE WILL INCREASE FROM THE CASCADES WEST DURING THIS PERIOD.
THE INCREASE IN MOISTURE...LIFT AND INSTABILITY WILL ALLOW SHOWERS
AND ISOLATED THUNDERSTORMS TO DEVELOP LATE THIS AFTERNOON INTO
THIS EVENING OVER SISKIYOU AND MODOC COUNTIES IN NORTHERN
CALIFORNIA AND OVER SOUTHWESTERN PORTIONS OF SOUTHERN
OREGON....MAINLY FROM KLAMATH COUNTY WEST. ADDITIONALLY A BAND OF
SHOWERS IS EXPECTED TO MOVE INTO THE CWA FROM THE SOUTH LATE THIS
EVENING AND TONIGHT. SOME ISOLATED EMBEDDED THUNDERSTORMS AS WELL
AS AREAS OF MODERATE TO HEAVY RAIN ARE ALSO POSSIBLE WITH THIS
LINE.
ON SUNDAY...THE LOW BEGINS TO MOVES INLAND TO THE SOUTH AND WILL
BRING CONTINUED MOISTURE AND SHOWERS TO THE AREA. BY
AFTERNOON...EXPECT SHOWERS TO BECOME WIDESPREAD OVER MOST THE
AREA. INSTABILITY INCREASES OVER THE AREA AGAIN SUNDAY
AFTERNOON. HAVE EXPANDED THE SLIGHT RISK OF THUNDERSTORMS OVER THE
INLAND AREAS SUNDAY AFTERNOON INTO SUNDAY EVENING GIVEN THE MODEL
CONSENSUS ON BETTER INSTABILITY...AS WELL AS INCREASED DIVERGENCE
ALOFT AND CONTINUED MOISTURE CONVERGENCE OVER PORTIONS OF THE CWA.
ON MONDAY...MODELS CONTINUE TO SHOW DIFFERENCES ON THE SPEED OF
THE LOW AS IT MOVES EAST INTO NEVADA AND UTAH WITH THE ECMWF
BEING SHOWER THAN THE GFS AND NAM. HAVE COMPROMISED IN THE
FORECAST WITH CHANCE POPS OVER THE CENTRAL AND EASTERN PORTIONS
OF THE CWA AND A SLIGHT CHANCE ELSEWHERE. BY MONDAY NIGHT EXPECT
SHOWER ACTIVITY TO DIMINISH ACROSS THE AREA AS A STRONG RIDGE OF
HIGH PRESSURE BUILDS INTO PLACE.
ON TUESDAY...A RIDGE WILL BRING DRY AND VERY WARM CONDITIONS WITH
HIGHS IN THE UPPER 60S TO MID 70S FOR VALLEYS WEST OF THE CASCADES
AND IN THE MID 60S EAST OF THE CASCADES. THESE WARM AND DRY
CONDITIONS CONTINUE INTO WEDNESDAY.
.LONG TERM...AN ACTIVE PATTERN IS IN THE WORKS STARTING NEXT
THURSDAY AND COULD LAST THROUGH NEXT WEEKEND. THE EC AND GFS
OPERATIONAL AND ENSEMBLE MEANS HAVE BEEN TRENDING IN THIS DIRECTION
FOR THE PAST FEW DAYS. SO CONFIDENCE IS BECOMING HIGHER WE`LL BE
HEADING INTO A COOLER AND WETTER PATTERN....BUT LESS CONFIDENT ON
THE TIMING OF EACH INDIVIDUAL SYSTEM. THE EC IS SLOWER THEN THE
GFS WITH A NEGATIVE TILTED TROUGH MOVING INTO THE AREA THURSDAY
AFTERNOON. SO WE`LL CONTINUE TO GO ABOVE CLIMO FROM THURSDAY
ONWARD IN THE EXTENDED. TEMPERATURES ARE ALSO LIKELY TO BE BELOW
NORMAL DURING THE DAY...BUT NEAR OR SLIGHTLY ABOVE NORMAL AT NIGHT
DUE TO CLOUD COVER AND PRECIPITATION. -PETRUCELLI
&&
.AVIATION...VFR CONDITIONS WILL CONTINUE INTO TONIGHT. HIGH AND MID
LEVEL CLOUDS WILL GRADUALLY INCREASE IN THE AFTERNOON WITH LIGHT
TO MODERATE EAST TO NORTHEAST WINDS ALOFT VEERING TO SOUTHERLY.
THE AIR MASS WILL DESTABILIZE LATE THIS THE AFTERNOON WITH SHOWERS
AND ISOLATED THUNDERSTORMS POSSIBLE OVER THE MOUNTAINS OF SISKIYOU
COUNTY. TEMPORARY MVFR CIGS ARE POSSIBLE EARLY SUNDAY MORNING IN
THE ROGUE VALLEY AND UMPQUA BASIN WITH PARTIAL MOUNTAIN
OBSCURATIONS. -PETRUCELLI
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
CC
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
949 AM EDT SAT MAR 30 2013
.DISCUSSION...
LOW LEVEL MOISTURE APPEARS TO BE TRAPPED IN THE TN VALLEY. WITH
VERY WEAK FLOW FROM THE SURFACE TO 850 MB...THE CLOUDS WILL
PROBABLY BE SLOWER TO CLEAR THAN MODELS INDICATE. EXPECT THAT
CLEARING WILL NOT COME UNTIL AROUND 18Z OR LATER BASED ON THE
LATEST RUC SOUNDINGS. THIS WILL AFFECT TEMPS...SO THE UPDATE WILL
MAKE SOME DOWNWARD ADJUSTMENTS.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DGS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1224 PM EDT SAT MAR 30 2013
.SYNOPSIS...
HIGH PRESSURE ACROSS THE REGION WILL GRADUALLY SHIFT EAST AND
OFFSHORE THIS AFTERNOON INTO TONIGHT. THIS WILL RESULT IN MILDER
TEMPERATURES AHEAD OF A COLD FRONT THAT WILL BRING A CHANCE OF
RAIN SHOWERS LATER TONIGHT INTO SUNDAY. ANOTHER COLD FRONT SHOULD
PROVIDE A RETURN TO COLDER CONDITIONS DURING NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1210 PM EDT SATURDAY...
ADJUSTED CLOUD COVER TO AC/CU
FIELDS IN THE MOUNTAINS. MODIFIED TEMPERATURES AND RAISE HIGH
TEMPERATURES A FEW DEGREES ESPECAILLY IN THE SOUTHEAST. WAITING TO
SEE IF ANY SHOWERS DEVELOP THIS AFTERNOON ACROSS THE HIGHER
TERRAIN.
AS OF 943 AM EDT SATURDAY...
THIS MORNING 8AM/12Z RNK SOUNDING DISPLAYED AN INVERSION AROUND
910MB WITH A POCKET OF MOISTURE ABOUT 720 MB AND A WEST TO
NORTHWEST FLOW. HIGH PRESSURE OVER OHIO THIS MORNING WILL TRAVEL
EAST TODAY INTO TONIGHT. THIS WILL RESULT IN PLEASANT WEATHER THIS
AFTERNOON FOR OUR REGION WITH SEASONABLE TEMPERATURES. RNK WRFARW
AND HRRR SUPPORT THE MENTION OF ISOLATED SHOWERS ACROSS SOUTHWEST
PORTIONS OF CWA THIS AFTERNOON AND EVENING. THE MAIN AREA OF RAIN
ASSOCIATED WITH THE WARM FRONT ON TRACK TO DEVELOP OVERNIGHT.
MADE SOME MINOR MODIFICATIONS TO TEMPERATURES...CLOUD COVER AND
POPS FOR TODAY.
AS OF 252 AM EDT SATURDAY...
WARMING TREND CONTINUES OVER THE NEXT 24 HOURS AS HIGH PRESSURE
ACROSS THE REGION THIS MORNING GRADUALLY SHIFTS EAST AND OFFSHORE
ALLOWING A WEAK WARM ADVECTION PATTERN TO TAKE SHAPE. WILL HAVE A
WEAK IMPULSE PASSING TO THE SOUTH EARLY THIS MORNING BEFORE THE
AREA WORKS INTO A WEAK SUBSIDENCE REGION BETWEEN THE RIDGE AND A
WARM FRONT TO THE SW THIS AFTERNOON. THIS LOOKS TO HELP DIMINISH
CLOUDS IN ALL AREAS EXCEPT PERHAPS THE FAR SW WHERE SOME MOISTURE
MAY GET STUCK FROM THE NW NC RIDGES INTO SW VA. MAY ALSO LEAVE IN
THE GOING ISOLATED -RA MENTION IN NW NC EARLY BEFORE DEEPER
MOISTURE EXITS WITH MORE OF AN AC TO CU FIELD ELSW THIS AFTERNOON.
LATEST MODEL THICKNESS COMBO WITH WEAK SW FLOW AND BASED ON MORE
INSOLATION SUPPORTS HIGHS LOW/MID 60S BLUE RIDGE EAST TODAY...AND
MID/UPPER 50S WEST OUTSIDE OF THE HIGHER ELEVATIONS.
WARM FRONT AND ASSOCIATED WEAK VORT AXIS WILL APPROACH FROM THE
SW OVERNIGHT HELPING TURN THE LOW LEVEL FLOW MORE SE THIS EVENING
AHEAD OF THE MAIN BODY OF DEEPER MOISTURE/SHRA THAT WILL BE
NEARING THE WEST SHORTLY AFTER MIDNIGHT. MODELS REMAIN RATHER
CONSISTENT IN SHOWING A SWATH OF BETTER LIFT ACROSS THE NW CLOSER
TO THE MAIN SHORTWAVE AXIS...AND ALONG THE SRN BLUE RIDGE WHERE
AIDED BY WEAK UPSLOPE AND PERHAPS A SECONDARY BAGGY WAVE ALONG THE
WARM FRONT LATE. THIS INITIAL UPSLOPE FLOW SUPPORTS GOING A BIT
FASTER WITH POPS OVERNIGHT WITH ALL EXCEPT THE EASTERN THIRD
SEEING LIKELY/CAT POPS BY DAYBREAK. CANT TOTALLY RULE OUT A RUMBLE
OF THUNDER ESPCLY SW GIVEN DECENT LIFT AND PUNCH OF WARM AIR
COMING IN WITH AN INCREASING 85H JET LIKELY WITH WHATS LEFT OF AN
EARLIER MCS. HOWEVER GIVEN FCST LOW LEVEL STABILITY WONT INCLUDE
FOR NOW. HEAVIEST QPF THRU DAWN LOOKS TO BE OVER THE FAR WEST WITH
AROUND A QUARTER TO ONE HALF INCH POSSIBLE ESPCLY WHERE ENHANCED
BY WEAK UPSLOPE AND SOME EMBEDDED CONVECTION ALOFT. LOW TEMPS
SHOULD BE MUCH MILDER THAN SEEN IN A WHILE WITH UPPER 30S TO MID
40S...WITH PERHAPS A FEW VALLEYS AND EASTERN SPOTS A BIT COLDER
EARLY ON BEFORE RISING LATE AS CLOUDS/SHRA ARRIVE.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 315 AM EDT SATURDAY...
A WARM FRONT WILL SPREAD A QUICK SHOT OF RAIN ACROSS THE REGION
DURING THE FIRST HALF OF SUNDAY. THE COLD FRONT HOLDS TO THE NW LONG
ENOUGH SO THAT MONDAY WILL FEATURE MANY HIGHS IN THE 60S WITH H85
TEMPS FROM +4C TO +8C. ALTHOUGH ITS BEEN SAID WAY TOO MANY TIMES
THIS MARCH...THE COLD SHOT ARRIVING MONDAY NIGHT THROUGH TUESDAY MAY
BE WINTER`S LAST GASP...WITH -10C AT H85 ONCE AGAIN TOUCHING SE WEST
VA. ALTHOUGH THE OP GFS IS GENERATING LIGHT SNOW ACROSS MOSTLY
GREENBRIER MONDAY NIGHT...ALL OTHER MODELS SAY NO...AND ARE MUCH
DRIER AT H85 AND H7.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 115 PM EDT FRIDAY...
COLDER AIR PUSHING IN WITH STRONG CANADIAN HIGH MOVING SE INTO
THE PLAINS. THIS HIGH MOVES INTO THE OHIO VALLEY BY WEDNESDAY AND
SHIFTS EAST OF US THURSDAY. TEMPS WILL AGAIN BE FALLING WELL BELOW
NORMAL WITH HIGHS TUE-WED IN THE UPPER 30S TO MID 40S MTNS...AND
MID 40S TO LOWER 50S EAST.
FOR THE THU NIGHT-FRI TIME FRAME...THE 00Z ECMWF SHOWS THE NEXT
SHORTWAVE PUSHING INTO THE OHIO VALLEY SOUTH TO THE GULF COAST.
MEANWHILE...THE 12Z GFS IS FASTER AND FURTHER SOUTH WITH ITS SYSTEM
KEEPING PRECIP MORE OVER THE SOUTHEAST. THE ECMWF WORKS A WARM FRONT
AND LOW NE TO THE AREA FRIDAY WITH RAIN...AND RETREATING HIGH
PRESSURE. LEANED THE FORECAST TOWARD A WETTER SOLUTION SIMILAR TO
THE ECMWF. SHOULD BE MAINLY RAIN BUT CANNOT RULE OUT SOME WINTRY
PRECIP IF THE COLD AIR IS SLOW TO DISLODGE.
BOTH MODELS AFTER FRIDAY CLOSE OFF AN UPPER LOW ALONG THE EAST
COAST...DELMARVA AREA FOR ECMWF AND EAST OF SOUTH CAROLINA FOR THE
GFS.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
AS OF 1205 PM EDT SATURDAY...
EXPECT GOOD FLYING CONDITIONS TO PREVAIL IN MOST AREAS
INTO/THROUGH EARLY THIS EVENING BEFORE THE APPROACH OF A WARM
FRONT BRINGS AN INCREASING THREAT OF SHOWERS ALONG WITH FLIGHT
RESTRICTIONS BACK INTO MVFR OR IFR RANGE LATER TONIGHT INTO MUCH
OF SUNDAY. LOOKS LIKE MOST OF THE RAINFALL WILL AFFECT THE WESTERN
TAF LOCATIONS SUCH AS KBLF/KBCB SHORTLY AFTER MIDNIGHT...AND THEN
PROGRESS NORTH/EAST OVER THE REMAINDER OF THE FORECAST POINTS BY
DAYBREAK. COULD SEE CIGS/VSBYS RAPIDLY LOWER AS WELL AROUND DAWN
ON SUNDAY AS A PERIOD OF MODERATE TO HEAVY RAIN TRACKS ACROSS
PARTS OF THE AREA AS WELL. AN ISOLATED THUNDERSTORM IS POSSIBLE.
BECAUSE OF THE LIMITED COVERAGE...LEFT OUT OF TAFS FOR NOW.
PASSAGE OF THE WARM FRONT EARLY AND SUBSEQUENT COLD FRONT LATER IN
THE DAY SHOULD BRING END TO RAIN THREAT ALONG WITH CLEARING SKIES
IN DOWNSLOPING AREAS EAST OF THE BLUE RIDGE BY LATE SUNDAY
AFTERNOON. HOWEVER TYPICAL UPSLOPING CLOUDS..AND POSSIBLY SOME
ISOLATED SHOWERS SHOULD MAINTAIN A THREAT FOR AT LEAST OCCASIONAL
MVFR CEILINGS THROUGH SUNDAY NIGHT ACROSS SOUTHEASTERN WV TERMINAL
FORECAST POINTS.
APPROACH OF MUCH MORE POTENT COLD FRONT WILL MAINTAIN MVFR TO
POSSIBLY IFR RESTRICTIONS WITH INCREASING THREAT OF PRECIPITATION
ACROSS UPSLOPE AREAS OF THE WEST LATER MONDAY INTO MONDAY
NIGHT. EXPECT VFR CONDITIONS EAST OF THE BLUE RIDGE TO BE OVERTAKEN
BY AT LEAST MVFR RESTRICTIONS MONDAY NIGHT INTO TUESDAY MORNING AS
COLD FRONT AND ASSOCIATED PRECIPITATION MOVE EAST THROUGH THE
AREA.
PROLONGED PERIOD OF COLD UPSLOPING WINDS AND SNOW SHOWERS WILL
AGAIN MAINTAIN MVFR TO OCCASIONAL IFR RESTRICTIONS TO WESTERN
FLANKS OF THE APPALACHIANS TUESDAY THROUGH WEDNESDAY...BUT WITH A
RETURN TO VFR WEATHER EXPECTED IN DOWNSLOPING AREAS EAST OF THE
BLUE RIDGE FOLLOWING FRONTAL PASSAGE TUESDAY AFTERNOON CONTINUING
INTO WEDNESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/WP
NEAR TERM...JH/KK
SHORT TERM...KM
LONG TERM...WP
AVIATION...JH/KK/WERT
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1008 AM EDT SAT MAR 30 2013
.SYNOPSIS...
HIGH PRESSURE ACROSS THE REGION WILL GRADUALLY SHIFT EAST AND
OFFSHORE THIS AFTERNOON INTO TONIGHT. THIS WILL RESULT IN MILDER
TEMPERATURES AHEAD OF A COLD FRONT THAT WILL BRING A CHANCE OF
RAIN SHOWERS LATER TONIGHT INTO SUNDAY. ANOTHER COLD FRONT SHOULD
PROVIDE A RETURN TO COLDER CONDITIONS DURING NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 943 AM EDT SATURDAY...
THIS MORNING 8AM/12Z RNK SOUNDING DISPLAYED AN INVERSION AROUND
910MB WITH A POCKET OF MOISTURE ABOUT 720 MB AND A WEST TO
NORTHWEST FLOW. HIGH PRESSURE OVER OHIO THIS MORNING WILL TRAVEL
EAST TODAY INTO TONIGHT. THIS WILL RESULT IN PLEASANT WEATHER THIS
AFTERNOON FOR OUR REGION WITH SEASONABLE TEMPERATURES. RNK WRFARW
AND HRRR SUPPORT THE MENTION OF ISOLATED SHOWERS ACROSS SOUTHWEST
PORTIONS OF CWA THIS AFTERNOON AND EVENING. THE MAIN AREA OF RAIN
ASSOCIATED WITH THE WARM FRONT ON TRACK TO DEVELOP OVERNIGHT.
MADE SOME MINOR MODIFICATIONS TO TEMPERATURES...CLOUD COVER AND
POPS FOR TODAY.
AS OF 252 AM EDT SATURDAY...
WARMING TREND CONTINUES OVER THE NEXT 24 HOURS AS HIGH PRESSURE
ACROSS THE REGION THIS MORNING GRADUALLY SHIFTS EAST AND OFFSHORE
ALLOWING A WEAK WARM ADVECTION PATTERN TO TAKE SHAPE. WILL HAVE A
WEAK IMPULSE PASSING TO THE SOUTH EARLY THIS MORNING BEFORE THE
AREA WORKS INTO A WEAK SUBSIDENCE REGION BETWEEN THE RIDGE AND A
WARM FRONT TO THE SW THIS AFTERNOON. THIS LOOKS TO HELP DIMINISH
CLOUDS IN ALL AREAS EXCEPT PERHAPS THE FAR SW WHERE SOME MOISTURE
MAY GET STUCK FROM THE NW NC RIDGES INTO SW VA. MAY ALSO LEAVE IN
THE GOING ISOLATED -RA MENTION IN NW NC EARLY BEFORE DEEPER
MOISTURE EXITS WITH MORE OF AN AC TO CU FIELD ELSW THIS AFTERNOON.
LATEST MODEL THICKNESS COMBO WITH WEAK SW FLOW AND BASED ON MORE
INSOLATION SUPPORTS HIGHS LOW/MID 60S BLUE RIDGE EAST TODAY...AND
MID/UPPER 50S WEST OUTSIDE OF THE HIGHER ELEVATIONS.
WARM FRONT AND ASSOCIATED WEAK VORT AXIS WILL APPROACH FROM THE
SW OVERNIGHT HELPING TURN THE LOW LEVEL FLOW MORE SE THIS EVENING
AHEAD OF THE MAIN BODY OF DEEPER MOISTURE/SHRA THAT WILL BE
NEARING THE WEST SHORTLY AFTER MIDNIGHT. MODELS REMAIN RATHER
CONSISTENT IN SHOWING A SWATH OF BETTER LIFT ACROSS THE NW CLOSER
TO THE MAIN SHORTWAVE AXIS...AND ALONG THE SRN BLUE RIDGE WHERE
AIDED BY WEAK UPSLOPE AND PERHAPS A SECONDARY BAGGY WAVE ALONG THE
WARM FRONT LATE. THIS INITIAL UPSLOPE FLOW SUPPORTS GOING A BIT
FASTER WITH POPS OVERNIGHT WITH ALL EXCEPT THE EASTERN THIRD
SEEING LIKELY/CAT POPS BY DAYBREAK. CANT TOTALLY RULE OUT A RUMBLE
OF THUNDER ESPCLY SW GIVEN DECENT LIFT AND PUNCH OF WARM AIR
COMING IN WITH AN INCREASING 85H JET LIKELY WITH WHATS LEFT OF AN
EARLIER MCS. HOWEVER GIVEN FCST LOW LEVEL STABILITY WONT INCLUDE
FOR NOW. HEAVIEST QPF THRU DAWN LOOKS TO BE OVER THE FAR WEST WITH
AROUND A QUARTER TO ONE HALF INCH POSSIBLE ESPCLY WHERE ENHANCED
BY WEAK UPSLOPE AND SOME EMBEDDED CONVECTION ALOFT. LOW TEMPS
SHOULD BE MUCH MILDER THAN SEEN IN A WHILE WITH UPPER 30S TO MID
40S...WITH PERHAPS A FEW VALLEYS AND EASTERN SPOTS A BIT COLDER
EARLY ON BEFORE RISING LATE AS CLOUDS/SHRA ARRIVE.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 315 AM EDT SATURDAY...
A WARM FRONT WILL SPREAD A QUICK SHOT OF RAIN ACROSS THE REGION
DURING THE FIRST HALF OF SUNDAY. THE COLD FRONT HOLDS TO THE NW LONG
ENOUGH SO THAT MONDAY WILL FEATURE MANY HIGHS IN THE 60S WITH H85
TEMPS FROM +4C TO +8C. ALTHOUGH ITS BEEN SAID WAY TOO MANY TIMES
THIS MARCH...THE COLD SHOT ARRIVING MONDAY NIGHT THROUGH TUESDAY MAY
BE WINTER`S LAST GASP...WITH -10C AT H85 ONCE AGAIN TOUCHING SE WEST
VA. ALTHOUGH THE OP GFS IS GENERATING LIGHT SNOW ACROSS MOSTLY
GREENBRIER MONDAY NIGHT...ALL OTHER MODELS SAY NO...AND ARE MUCH
DRIER AT H85 AND H7.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 115 PM EDT FRIDAY...
COLDER AIR PUSHING IN WITH STRONG CANADIAN HIGH MOVING SE INTO
THE PLAINS. THIS HIGH MOVES INTO THE OHIO VALLEY BY WEDNESDAY AND
SHIFTS EAST OF US THURSDAY. TEMPS WILL AGAIN BE FALLING WELL BELOW
NORMAL WITH HIGHS TUE-WED IN THE UPPER 30S TO MID 40S MTNS...AND
MID 40S TO LOWER 50S EAST.
FOR THE THU NIGHT-FRI TIME FRAME...THE 00Z ECMWF SHOWS THE NEXT
SHORTWAVE PUSHING INTO THE OHIO VALLEY SOUTH TO THE GULF COAST.
MEANWHILE...THE 12Z GFS IS FASTER AND FURTHER SOUTH WITH ITS SYSTEM
KEEPING PRECIP MORE OVER THE SOUTHEAST. THE ECMWF WORKS A WARM FRONT
AND LOW NE TO THE AREA FRIDAY WITH RAIN...AND RETREATING HIGH
PRESSURE. LEANED THE FORECAST TOWARD A WETTER SOLUTION SIMILAR TO
THE ECMWF. SHOULD BE MAINLY RAIN BUT CANNOT RULE OUT SOME WINTRY
PRECIP IF THE COLD AIR IS SLOW TO DISLODGE.
BOTH MODELS AFTER FRIDAY CLOSE OFF AN UPPER LOW ALONG THE EAST
COAST...DELMARVA AREA FOR ECMWF AND EAST OF SOUTH CAROLINA FOR THE
GFS.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
AS OF 650 AM EDT SATURDAY...
AN UPPER LEVEL DISTURBANCE WILL CONTINUE TO TRACK SE OF THE AREA
THIS MORNING ALLOWING A REDUCTION IN COVERAGE OF LOW/MID CLOUDS
THROUGH MIDDAY. APPEARS ANY LEFTOVER MID DECK OR STRATO-CU LAYER
ALONG WITH PATCHY FOG WILL QUICKLY MIX OUT THIS MORNING PER
HEATING TO MORE SCTD/BKN VFR LEVEL CU BY AFTERNOON. THUS EXPECT
GOOD FLYING CONDITIONS TO PREVAIL IN MOST AREAS INTO/THROUGH EARLY
THIS EVENING BEFORE THE APPROACH OF A WARM FRONT BRINGS AN
INCREASING THREAT OF SHOWERS ALONG WITH FLIGHT RESTRICTIONS BACK
INTO MVFR OR IFR RANGE LATER TONIGHT INTO MUCH OF SUNDAY. LOOKS
LIKE MOST OF THE RAINFALL WILL AFFECT THE WESTERN TAF LOCATIONS
SUCH AS KBLF/KBCB SHORTLY AFTER MIDNIGHT...AND THEN PROGRESS
NORTH/EAST OVER THE REMAINDER OF THE FORECAST POINTS BY DAYBREAK.
COULD SEE CIGS/VSBYS RAPIDLY LOWER AS WELL AROUND DAWN ON SUNDAY
AS A PERIOD OF MODERATE TO HEAVY RAIN TRACKS ACROSS PARTS OF THE
AREA AS WELL.
PASSAGE OF THE WARM FRONT EARLY AND SUBSEQUENT COLD FRONT LATER IN
THE DAY SHOULD BRING END TO RAIN THREAT ALONG WITH CLEARING SKIES
IN DOWNSLOPING AREAS EAST OF THE BLUE RIDGE BY LATE SUNDAY
AFTERNOON. HOWEVER TYPICAL UPSLOPING CLOUDS..AND POSSIBLY SOME
ISOLATED SHOWERS SHOULD MAINTAIN A THREAT FOR AT LEAST OCCASIONAL
MVFR CEILINGS THROUGH SUNDAY NIGHT ACROSS SOUTHEASTERN WV TERMINAL
FORECAST POINTS.
APPROACH OF MUCH MORE POTENT COLD FRONT WILL MAINTAIN MVFR TO
POSSIBLY IFR RESTRICTIONS WITH INCREASING THREAT OF PRECIPITATION
ACROSS UPSLOPE AREAS OF THE WEST LATER MONDAY INTO MONDAY
NIGHT. EXPECT VFR CONDITIONS EAST OF THE BLUE RIDGE TO BE OVERTAKEN
BY AT LEAST MVFR RESTRICTIONS MONDAY NIGHT INTO TUESDAY MORNING AS
COLD FRONT AND ASSOCIATED PRECIPITATION MOVE EAST THROUGH THE
AREA.
PROLONGED PERIOD OF COLD UPSLOPING WINDS AND SNOW SHOWERS WILL
AGAIN MAINTAIN MVFR TO OCCASIONAL IFR RESTRICTIONS TO WESTERN
FLANKS OF THE APPALACHIANS TUESDAY THROUGH WEDNESDAY...BUT WITH A
RETURN TO VFR WEATHER EXPECTED IN DOWNSLOPING AREAS EAST OF THE
BLUE RIDGE FOLLOWING FRONTAL PASSAGE TUESDAY AFTERNOON CONTINUING
INTO WEDNESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/WP
NEAR TERM...JH/KK
SHORT TERM...KM
LONG TERM...WP
AVIATION...JH/WERT
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
126 AM EDT MON APR 1 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL OVERNIGHT. A COLD FRONT WILL
MOVE ACROSS THE AREA LATE MONDAY AFTERNOON INTO MONDAY
EVENING...FOLLOWED BY HIGH PRESSURE BUILDING FROM THE NORTH
THROUGH THE MIDDLE OF THE WEEK. A LOW PRESSURE SYSTEM WILL THEN
PASS ALONG THE SOUTHEAST COAST LATE IN THE WEEK INTO EARLY NEXT
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
UPSTREAM PCPN TRENDS AND LATEST RAP MODEL DATA HAVE TRENDED A BIT
SLOWER WITH RAIN REACHING THE I-95 CORRIDOR THROUGH 6 AM. WE KNOCKED
BACK POPS ALONG AND E OF I-95 DOWN ON THE MIDNIGHT UPDATE. TEMPS
WILL BE NO LOWER THAN THE UPPER 50S AND LOWER 60S...MAKING THEM
THE WARMEST NIGHT TIME LOWS IN MANY LOCALES SINCE FEBRUARY 11TH.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
MONDAY...A COLD FRONT WILL BE SITUATED ACROSS THE SOUTH CAROLINA
MIDLANDS AND EAST-CENTRAL GEORGIA TO START THE DAY...WITH AN AXIS OF
DEEP MOISTURE IN PLACE OVER THE AREA AHEAD OF THE FRONT WHERE
PRECIPITABLE WATER VALUES WILL PEAK AROUND 1.3 TO 1.4 INCHES. THE
DEEP MOISTURE COMBINED WITH FORCING FROM THE RIGHT ENTRANCE REGION
OF A WEAKENING H25 JET WILL SUPPORT NUMEROUS SHOWERS ACROSS THE AREA
IN THE MORNING. THE SHOWERS WILL THEN BEGIN TO TAPER OFF FROM THE
WEST DURING THE AFTERNOON AS THE FRONT SHIFTS ACROSS THE AREA AND
OFFSHORE BY LATE IN THE DAY. SOME THUNDERSTORMS ARE POSSIBLE...A FEW
OF WHICH COULD BE STRONG/SEVERE AT TIMES WITH SURFACE BASED CAPE
VALUES OF 800-1000 J/KG AND...LI VALUES OF -3C TO -5C AND MID LEVEL
LAPSE RATES OF 6-7 C/KM. WET BULB ZERO HEIGHTS POSSIBLY REACHING AS
LOW AS 8-9K FT WILL SUPPORT A HAIL THREAT...WITH DAMAGING WINDS ALSO
POSSIBLE. THE GREATEST POTENTIAL FOR ANY STRONG/SEVERE THUNDERSTORMS
APPEARS TO BE ACROSS SOUTHEAST GEORGIA...BUT GIVEN UNCERTAINTY IN
THE EXTENT OF DIURNAL HEATING THAT CAN TAKE PLACE DUE TO EXTENSIVE
CLOUD COVER AND PRECIPITATION...WILL KEEP MENTION OUT OF THE
HAZARDOUS WEATHER OUTLOOK FOR NOW. DESPITE THE EXTENSIVE CLOUD COVER
INITIALLY...A GOOD SOUTHWEST FLOW AND WEAK COMPRESSIONAL HEATING
AHEAD OF THE FRONT FOLLOWED BY A WARM WESTERLY FLOW IN ITS WAKE
SHOULD ALLOW TEMPERATURES TO REACH HIGHS IN THE MID 70S ACROSS THE
AREA AWAY FROM THE COOLER IMMEDIATE COAST.
MONDAY NIGHT...A SECONDARY COLD FRONT WILL SWING THROUGH THE AREA
DURING THE EVENING...WITH A DEVELOPING NORTHWEST/NORTH FLOW
ADVECTING A DRIER AIRMASS INTO THE REGION. ANY LINGERING ISOLATED
SHOWERS EARLY IN THE EVENING WILL QUICKLY COME TO AN END...WITH
MOSTLY CLEAR TO PARTLY CLOUDY SKIES EXPECTED THROUGH THE REMAINDER
OF THE NIGHT. LOW TEMPERATURES WILL BE IN THE UPPER 40S TO LOWER
50S.
TUESDAY AND TUESDAY NIGHT...A WEAK BUBBLE HIGH WILL SETTLE OVER THE
CAROLINAS WITH A NEARLY ZONAL FLOW IN PLACE ALOFT. RAIN-FREE
CONDITIONS AND PARTLY CLOUDY SKIES ARE EXPECTED. A WEAK DOWNSLOPE
FLOW ALOFT SHOULD HELP TEMPERATURES REACHES HIGH ON TUESDAY IN THE
LOWER TO MID 70S ACROSS MUCH OF THE AREA AWAY FROM THE IMMEDIATE
COAST...WITH SOME UPPER 70S EVEN POSSIBLE SOUTH OF THE I-16
CORRIDOR. LOWS TUESDAY NIGHT WILL BE IN THE UPPER 40S TO LOWER 50S
ONCE AGAIN.
WEDNESDAY...IT APPEARS THAT A WEAK BACKDOOR COLD FRONT DROPS THROUGH
THE AREA IN RESPONSE TO A STRONGER WEDGE OF HIGH PRESSURE BUILDING
FROM THE NORTH. THERE IS SOME MODEL DISAGREEMENT WITH RESPECT TO THE
EXTENT OF MOISTURE ACCOMPANYING THE BUILDING WEDGE...WITH THE NAM
MUCH MORE AGGRESSIVE THAN THE OTHER MODELS. WHILE THE CONSENSUS IS
FOR NOT MUCH IN THE WAY OF RAINFALL STILL FEEL THAN AN ISOLATED
SHOWER CANNOT BE RULED OUT AND THE FORECAST INDICATES A SLIGHT
CHANCE OF RAIN AS A RESULT. THE TEMPERATURE FORECAST IS ALSO TRICKY
AND THERE WILL LIKELY BE A LARGE GRADIENT ACROSS THE AREA...BUT FEEL
THE SAFEST BET IS TO FORECAST HIGHS RANGING FROM THE LOWER AND MID
60S IN SOUTHEAST SOUTH CAROLINA TO THE UPPER 60S AND LOWER 70S IN
SOUTHEAST GEORGIA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
WEDNESDAY NIGHT THROUGH FRIDAY...WE WILL SEE A TRANSITION TO A MUCH
WETTER PATTERN AS A SFC LOW DEEPENS OVER THE NORTHERN GULF WHILE AN
H5 SHORTWAVE DIGS OVER THE DEEP SOUTH. PRECIP CHANCES WILL INCREASE
IN SOUTHEAST GEORGIA..THEN INTO SOUTHEAST SOUTH CAROLINA AS AN
EASTWARD EXTENDING WARM FRONT DEVELOPS WEDNESDAY NIGHT AND BECOMES
POSITIONED ALONG THE SOUTHEAST COAST THURSDAY. THE AMOUNT OF
RAINFALL ASSOCIATED WITH THIS SYSTEM WILL BE HIGHLY DEPENDENT ON THE
POSITION OF THE WARM FRONT AND THE TRACK OF THE SFC LOW FROM THE
NORTHERN GULF OF MEXICO TO THE SOUTHEAST COAST.
AT THIS TIME...HIGH PRESSURE LOOKS TO MAINTAIN SOME HOLD OVER THE
FORECAST AREA...THUS FORCING A MORE SOUTHERN TRACK OF THE SFC LOW
OVER NORTHERN FLORIDA AND THEN ALONG THE SOUTHEAST COAST. WITH THIS
TRACK IN MIND...HAVE INTRODUCED LIKELY POPS OVER SOUTHEAST GEORGIA
AND CHANCE POPS OVER SOUTHEAST SOUTH CAROLINA WEDNESDAY NIGHT...WITH
LIKELY POPS ACROSS THE AREA THURSDAY AND THURSDAY NIGHT BEFORE THE
SFC LOW RAPIDLY DEEPENS AND SHIFTS TO THE NORTHEAST FRIDAY. SHOULD A
MORE NORTHERN TRACK TAKE PLACE...A CHANCE OF THUNDERSTORMS WILL
LIKELY NEED TO BE INTRODUCED OVER THE AREA. OVERALL TEMPS SHOULD
REMAIN COOL ON THURSDAY WITH HIGH PRESSURE MAINTAINING A HOLD.
OVERALL TEMPS SHOULD RANGE BETWEEN THE UPPER 50S NORTH...TO LOW/MID
60S SOUTH. BY FRIDAY...TEMPS SHOULD MODIFY A FEW DEGREES WITH THE
WARM FRONT ALONG THE COAST. OVERNIGHT LOWS SHOULD REACH THE LOW/MID
40S WEDNESDAY NIGHT AND UPPER 40S TO LOWER 50S THURSDAY AND FRIDAY
NIGHT.
SATURDAY AND SUNDAY...A DRY AND WARMING TREND IS ANTICIPATED FOR THE
SECOND HALF OF THE WEEKEND AS MID LVL RIDGING GRADUALLY EXPANDS INTO
THE SOUTHEAST. WITH LITTLE CLOUD ANTICIPATED...OVERALL TEMPS SHOULD
REACH THE UPPER 60S TO LOWER 70S SATURDAY AND LOWER 70S OVER MOST
LOCATIONS ON SUNDAY.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
OVERNIGHT WE HAVE MAINTAINED VFR WITH DRY WEATHER AT KSAV AND KCHS.
LATEST MODEL GUIDANCE SUGGESTS THE BEST TIMING FOR SCATTERED SHOWERS
WILL BE FROM 8 AM TO ABOUT NOON TODAY. TSTMS ARE POSSIBLE BUT TOO
EARLY/UNCERTAIN TO INTRO TSRA/CB AT THIS TIME. THIS AFTERNOON...WEST
WINDS WILL DIMINISH RAIN CHANCES AND MVFR CIG POTENTIAL BUT WILL
HAVE TO WATCH FOR ISOLATED TSTMS AHEAD OF THE COLD FRONT. AFTER
SUNSET...VFR CONDITIONS TO ALSO PREVAIL.
EXTENDED AVIATION OUTLOOK...VFR CONDITIONS SHOULD PREVAIL THROUGH
WEDNESDAY. MVFR OR LOWER CIGS/VSBYS ARE POSSIBLE WEDNESDAY NIGHT
THROUGH FRIDAY MORNING DUE TO RAIN/SHOWERS ASSOCIATED WITH A SFC
LOW TRACKING OVER NORTHERN FLORIDA AND THEN ALONG THE SOUTHEAST
COAST.
&&
.MARINE...
OVERNIGHT...THE COASTAL WATERS WILL BE SITUATED UNDER THE NW
FRINGES OF ATLANTIC RIDGING...WITH AN UPSTREAM COLD FRONT OVER THE
SE UNITED STATES. THE PRESSURE GRADIENT BETWEEN THESE TWO SYNOPTIC
FEATURES WILL BE TIGHT ENOUGH WHERE SOUTH AND SW WINDS WILL REMAIN
ELEVATED. SPEEDS WILL BE A SOLID 15 OR 20 KT OVER THE OCEAN...WITH
FREQUENT GUSTS OF 25 KT ACROSS THE OUTER GA WATERS. IT IS THERE
WHERE WE HAVE MAINTAINED THE SCA. IN CHARLESTON HARBOR WINDS WILL
GENERALLY HOLD UNDER 15 KT. DUE TO THESE WINDS AND A SOMEWHAT
FAVORABLE FETCH...SEAS WILL BE AS HIGH AS 3-5 FT WITHIN 20 NM OF THE
SHORE...BUT 4-6 FT ACROSS THE GA WATERS 20-60 NM OUT.
MONDAY THROUGH FRIDAY...SOUTHWEST FLOW WILL PREVAIL AHEAD OF AN
APPROACHING COLD FRONT MONDAY...WITH A TIGHT SURFACE PRESSURE
GRADIENT SUPPORTING MARGINAL SMALL CRAFT ADVISORY CONDITIONS OVER
PORTIONS OF THE OUTER GEORGIA WATERS DURING THE MORNING. CONDITIONS
WILL IMPROVE FOLLOWING THE PASSAGE OF A COLD FRONT MONDAY EVENING AS
WINDS SHIFT OFFSHORE. BUILDING HIGH PRESSURE WILL ALLOW A NORTHEAST
SURGE TO DEVELOP LATE MONDAY NIGHT INTO TUESDAY...WITH WINDS PEAKING
AROUND 15-20 KT. WEAK HIGH PRESSURE OVER THE CAROLINAS WILL THEN
KEEP CONDITIONS RATHER BENIGN OVER THE WATERS THROUGH TUESDAY NIGHT.
A WEAK BACK DOOR COLD FRONT WILL DROP THROUGH AS STRONGER HIGH
PRESSURE BUILDS FROM THE NORTH ON WEDNESDAY...CAUSING WINDS/SEAS TO
BEGIN DETERIORATING LATE WEDNESDAY AND WEDNESDAY NIGHT. SMALL CRAFT
ADVISORY CONDITIONS ARE THEN LIKELY LATE WEEK AS CONDITIONS
DETERIORATE FURTHER DUE TO AN ENHANCED PRESSURE GRADIENT BETWEEN
HIGH PRESSURE OVER THE WESTERN ATLANTIC AND LOW PRESSURE OVER THE
NORTHERN GULF ON THURSDAY FOLLOWED BY THE PASSAGE OF A COASTAL LOW
ALONG THE SOUTHEAST COAST THURSDAY NIGHT INTO FRIDAY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR AMZ374.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...JAQ
LONG TERM...DPB/JAQ
AVIATION...
MARINE...
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
415 AM EDT MON APR 1 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 353 AM EDT MON APR 1 2013
A WEAK UPPER WAVE WILL MOVE THROUGH THE AREA THIS MORNING BUT HIGH
PRESSURE WILL BUILD IN THIS AFTERNOON AND KEEP DRY WEATHER ACROSS
THE AREA THROUGH SATURDAY. SATURDAY NIGHT A LOW PRESSURE SYSTEM WILL
APPROACH AND BRING CHANCES FOR RAIN. TEMPERATURES WILL BE WELL BELOW
NORMAL TODAY THROUGH TUESDAY NIGHT AND THEN REBOUND TO ABOVE NORMAL
BY THE WEEKEND.
&&
.NEAR TERM /TODAY/...
ISSUED AT 353 AM EDT MON APR 1 2013
FORECAST FOCUS IS ON NEED FOR ANY POPS FROM EARLY TO MID MORNING.
UPPER WAVE IS CURRENTLY MOVING SOUTHEAST THROUGH SOUTHERN IOWA AND
WESTERN ILLINOIS. RADAR MOSAIC SHOWS WEAK ECHOES OVER WESTERN AND
CENTRAL ILLINOIS AS WELL AS SOME ENTERING WESTERN INDIANA BUT
SURFACE OBS SHOW NO PRECIP AT THE GROUND. GFS AND NAM ARE BOTH DRY
AND GUIDANCE IS AS WELL. RAPID REFRESH AND RAP SHOW SOME DEVELOPMENT
OCCURRING ACROSS THE SOUTHERN COUNTIES AROUND 11-12Z AND MOVING
THROUGH BY 15Z. WITH BOTH OF THE RAPID UPDATE MODELS SHOWING THIS
DEVELOPMENT WILL GO AHEAD AND LEAVE A SLIGHT CHANCE FOR RAIN AND
SNOW MOVING ACROSS THE SOUTH FROM 11 TO 15Z AND DRY FROM 15Z ON.
SHOULD NOT AMOUNT TO ANYTHING. WILL DROP ANY MENTION OF FLURRIES
ELSEWHERE.
CLOUDS SHOULD SCATTER OUT AS THE DAY GOES ON. WILL SEE COLD
ADVECTION THROUGHOUT THE DAY SO TEMPERATURES SHOULD STRUGGLE TO WARM
AND THUS WENT WITH A CONSENSUS OF RAW MODEL NUMBERS SINCE
CLIMATOLOGY COULD BIAS THINGS UP.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 353 AM EDT MON APR 1 2013
HIGH PRESSURE WILL DOMINATE THE WEATHER IN THE SHORT TERM. MODELS
ARE IN GOOD AGREEMENT AND WILL USE A CONSENSUS. WITH MOSTLY CLEAR TO
CLEAR SKIES THROUGHOUT THE SHORT TERM STUCK CLOSE TO COOLER GUIDANCE
NUMBERS AT NIGHT OF LOW TO MIDDLE 20S. FOR HIGHS TUESDAY AGAIN THOUGHT
GUIDANCE WAS BIASED A BIT WARM FROM CLIMATOLOGY SO STUCK WITH A RAW
MODEL CONSENSUS IN THE LOW TO MID 40S...BUT BY WEDNESDAY THE AIR
MASS SHOULD BE REBOUNDING UNDER WARM ADVECTION AND A COMPLETE
CONSENSUS LOOKED GOOD IN THE UPPER 40S TO LOW 50S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ISSUED AT 324 AM EDT MON APR 1 2013
A LARGE AREA OF HIGH PRESSURE WILL BE MOVING AWAY TO THE EAST ON
THURSDAY WITH A SPLIT FLOW PATTERN ALOFT AS A WEAK FRONT
APPROACHES FROM THE NORTHWEST AND AN UPPER LOW TRACKS ACROSS THE
SOUTHERN PLAINS. MODEL CONSENSUS HAS BEEN TRACKING THE UPPER WAVE
FURTHER NORTH OVER THE LAST COUPLE DAYS AND BRINGS THE NORTHERN
FRINGES OF THE RAINFALL ASSOCIATED WITH THE UPPER LOW INTO THE
OHIO RIVER VALLEY THURSDAY NIGHT. CONSIDERING THE NORTHERLY LOW
LEVEL FLOW...PRESENCE OF DRIER AIR OVER THE REGION AND THE BULK OF
THE DEEPER FORCING REMAINING TO THE SOUTH OF THE FORECAST
AREA...WILL CONTINUE TO KEEP A DRY FORECAST GOING THURSDAY NIGHT.
DO ANTICIPATE AN INCREASE IN CLOUDS OVER THE SOUTHERN COUNTIES
THURSDAY NIGHT AND EARLY FRIDAY AS THE UPPER WAVE PASSES TO THE
SOUTH. THE AFOREMENTIONED WEAK FRONT APPROACHING FROM THE
NORTHWEST SET TO WASH OUT ACROSS THE LOWER GREAT LAKES THURSDAY
NIGHT.
AS THE UPPER WAVE WEAKENS AND SHIFTS INTO THE SOUTHEAST STATES BY
FRIDAY AFTERNOON...HIGH PRESSURE WILL REESTABLISH ACROSS THE OHIO
VALLEY WITH AN EXPANSION OF RIDGING ALOFT BRINGING WARMER AIR INTO
THE REGION. LOW LEVEL THERMALS SUPPORT HIGH TEMPS RISING INTO THE 60S
BY SATURDAY. FORECAST MORE MUDDLED FOR THE SECOND HALF OF THE
WEEKEND AS A DEVELOPING WARM FRONT SETS UP OVER THE LOWER GREAT
LAKES AND A SURFACE WAVE TRACKS ALONG THE BOUNDARY ON SUNDAY. WILL
CARRY LOW CHANCE POPS SATURDAY NIGHT INTO SUNDAY AS THE SURFACE
WAVE PASSES THROUGH THE AREA. APPEARS THE BOUNDARY MAY SETTLE
FURTHER SOUTH NEAR THE OHIO RIVER BY LATE SUNDAY WITH THE PASSAGE
OF THE LOW...BEFORE THE BOUNDARY RETURNS BACK NORTH EARLY NEXT
WEEK. LOW LEVEL THERMALS STILL SUGGESTIVE OF HIGHS IN THE 60S FOR
SUNDAY EVEN AS THE BOUNDARY SHIFTS SOUTH...WITH POSSIBILITY FOR
WARMER DAYTIME HIGHS EARLY NEXT WEEK ONCE THE FRONT LIFTS BACK
NORTH.
&&
.AVIATION /DISCUSSION FOR THE 010900Z TAF UPDATE/...
ISSUED AT 415 AM EDT MON APR 1 2013
MID LEVEL CLOUDS EXPANDING BACK ACROSS THE TERMINALS EARLY THIS
MORNING AS THE UPPER TROUGH SHARPENS OVER THE REGION. TWEAKED CLOUDS
AND WIND SPEEDS BASED ON CURRENT OBS WITH EXPECTATION OF SOME GUSTS
APPROACHING 20KTS THROUGH THE MORNING. AREA OF SCATTERED LIGHT SNOW
SHOWERS/FLURRIES OVER NORTHEAST MISSOURI AND WESTERN ILLINOIS WILL
MOVE EAST TOWARDS THE REGION BY DAYBREAK. AT THIS POINT HOWEVER...
STILL APPEARS THIS AREA OF PRECIP WILL CONTINUE TO WEAKEN WITH
POSSIBILITY OF JUST A FEW FLURRIES AT KBMG/KHUF/KIND IN THE 12-15Z
PERIOD. WILL MAINTAIN NO PRECIP MENTION IN TERMINALS AT THIS TIME.
06Z DISCUSSION FOLLOWS.
VFR THROUGH THE PERIOD.
SCT TO BKN MID CLOUD LIKELY THE ONLY SKY COVER THROUGH THE NIGHT.
WINDS WILL ONCE AGAIN GUST TOMORROW TO NEAR 20KT...AND DIURNAL
CUMULUS WILL FORM AROUND 5KFT.
NO VISIBILITY ISSUES ANTICIPATED THROUGH THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....RYAN
AVIATION...NIELD/RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
400 AM EDT MON APR 1 2013
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 353 AM EDT MON APR 1 2013
A WEAK UPPER WAVE WILL MOVE THROUGH THE AREA THIS MORNING BUT HIGH
PRESSURE WILL BUILD IN THIS AFTERNOON AND KEEP DRY WEATHER ACROSS
THE AREA THROUGH SATURDAY. SATURDAY NIGHT A LOW PRESSURE SYSTEM WILL
APPROACH AND BRING CHANCES FOR RAIN. TEMPERATURES WILL BE WELL BELOW
NORMAL TODAY THROUGH TUESDAY NIGHT AND THEN REBOUND TO ABOVE NORMAL
BY THE WEEKEND.
&&
.NEAR TERM /TODAY/...
ISSUED AT 353 AM EDT MON APR 1 2013
FORECAST FOCUS IS ON NEED FOR ANY POPS FROM EARLY TO MID MORNING.
UPPER WAVE IS CURRENTLY MOVING SOUTHEAST THROUGH SOUTHERN IOWA AND
WESTERN ILLINOIS. RADAR MOSAIC SHOWS WEAK ECHOES OVER WESTERN AND
CENTRAL ILLINOIS AS WELL AS SOME ENTERING WESTERN INDIANA BUT
SURFACE OBS SHOW NO PRECIP AT THE GROUND. GFS AND NAM ARE BOTH DRY
AND GUIDANCE IS AS WELL. RAPID REFRESH AND RAP SHOW SOME DEVELOPMENT
OCCURRING ACROSS THE SOUTHERN COUNTIES AROUND 11-12Z AND MOVING
THROUGH BY 15Z. WITH BOTH OF THE RAPID UPDATE MODELS SHOWING THIS
DEVELOPMENT WILL GO AHEAD AND LEAVE A SLIGHT CHANCE FOR RAIN AND
SNOW MOVING ACROSS THE SOUTH FROM 11 TO 15Z AND DRY FROM 15Z ON.
SHOULD NOT AMOUNT TO ANYTHING. WILL DROP ANY MENTION OF FLURRIES
ELSEWHERE.
CLOUDS SHOULD SCATTER OUT AS THE DAY GOES ON. WILL SEE COLD
ADVECTION THROUGHOUT THE DAY SO TEMPERATURES SHOULD STRUGGLE TO WARM
AND THUS WENT WITH A CONSENSUS OF RAW MODEL NUMBERS SINCE
CLIMATOLOGY COULD BIAS THINGS UP.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 353 AM EDT MON APR 1 2013
HIGH PRESSURE WILL DOMINATE THE WEATHER IN THE SHORT TERM. MODELS
ARE IN GOOD AGREEMENT AND WILL USE A CONSENSUS. WITH MOSTLY CLEAR TO
CLEAR SKIES THROUGHOUT THE SHORT TERM STUCK CLOSE TO COOLER GUIDANCE
NUMBERS AT NIGHT OF LOW TO MIDDLE 20S. FOR HIGHS TUESDAY AGAIN THOUGHT
GUIDANCE WAS BIASED A BIT WARM FROM CLIMATOLOGY SO STUCK WITH A RAW
MODEL CONSENSUS IN THE LOW TO MID 40S...BUT BY WEDNESDAY THE AIR
MASS SHOULD BE REBOUNDING UNDER WARM ADVECTION AND A COMPLETE
CONSENSUS LOOKED GOOD IN THE UPPER 40S TO LOW 50S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ISSUED AT 324 AM EDT MON APR 1 2013
A LARGE AREA OF HIGH PRESSURE WILL BE MOVING AWAY TO THE EAST ON
THURSDAY WITH A SPLIT FLOW PATTERN ALOFT AS A WEAK FRONT
APPROACHES FROM THE NORTHWEST AND AN UPPER LOW TRACKS ACROSS THE
SOUTHERN PLAINS. MODEL CONSENSUS HAS BEEN TRACKING THE UPPER WAVE
FURTHER NORTH OVER THE LAST COUPLE DAYS AND BRINGS THE NORTHERN
FRINGES OF THE RAINFALL ASSOCIATED WITH THE UPPER LOW INTO THE
OHIO RIVER VALLEY THURSDAY NIGHT. CONSIDERING THE NORTHERLY LOW
LEVEL FLOW...PRESENCE OF DRIER AIR OVER THE REGION AND THE BULK OF
THE DEEPER FORCING REMAINING TO THE SOUTH OF THE FORECAST
AREA...WILL CONTINUE TO KEEP A DRY FORECAST GOING THURSDAY NIGHT.
DO ANTICIPATE AN INCREASE IN CLOUDS OVER THE SOUTHERN COUNTIES
THURSDAY NIGHT AND EARLY FRIDAY AS THE UPPER WAVE PASSES TO THE
SOUTH. THE AFOREMENTIONED WEAK FRONT APPROACHING FROM THE
NORTHWEST SET TO WASH OUT ACROSS THE LOWER GREAT LAKES THURSDAY
NIGHT.
AS THE UPPER WAVE WEAKENS AND SHIFTS INTO THE SOUTHEAST STATES BY
FRIDAY AFTERNOON...HIGH PRESSURE WILL REESTABLISH ACROSS THE OHIO
VALLEY WITH AN EXPANSION OF RIDGING ALOFT BRINGING WARMER AIR INTO
THE REGION. LOW LEVEL THERMALS SUPPORT HIGH TEMPS RISING INTO THE 60S
BY SATURDAY. FORECAST MORE MUDDLED FOR THE SECOND HALF OF THE
WEEKEND AS A DEVELOPING WARM FRONT SETS UP OVER THE LOWER GREAT
LAKES AND A SURFACE WAVE TRACKS ALONG THE BOUNDARY ON SUNDAY. WILL
CARRY LOW CHANCE POPS SATURDAY NIGHT INTO SUNDAY AS THE SURFACE
WAVE PASSES THROUGH THE AREA. APPEARS THE BOUNDARY MAY SETTLE
FURTHER SOUTH NEAR THE OHIO RIVER BY LATE SUNDAY WITH THE PASSAGE
OF THE LOW...BEFORE THE BOUNDARY RETURNS BACK NORTH EARLY NEXT
WEEK. LOW LEVEL THERMALS STILL SUGGESTIVE OF HIGHS IN THE 60S FOR
SUNDAY EVEN AS THE BOUNDARY SHIFTS SOUTH...WITH POSSIBILITY FOR
WARMER DAYTIME HIGHS EARLY NEXT WEEK ONCE THE FRONT LIFTS BACK
NORTH.
&&
.AVIATION /DISCUSSION FOR THE 01/06Z TAFS/...
ISSUED AT 104 AM EDT MON APR 1 2013
VFR THROUGH THE PERIOD.
SCT TO BKN MID CLOUD LIKELY THE ONLY SKY COVER THROUGH THE NIGHT.
WINDS WILL ONCE AGAIN GUST TOMORROW TO NEAR 20KT...AND DIURNAL
CUMULUS WILL FORM AROUND 5KFT.
NO VISIBILITY ISSUES ANTICIPATED THROUGH THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....RYAN
AVIATION...NIELD
AREA FORECAST DISCUSSION
NWS WICHITA KS
335 AM CDT MON APR 1 2013
.SYNOPSIS...
ISSUED AT 332 AM CDT MON APR 1 2013
A POTENT DISTURBANCE IS PLUNGING SOUTHWARD INTO THE GREAT LAKES
REGION...CAUSING A COLD FRONT TO DIVE SOUTHWARD ACROSS THE CENTRAL
PLAINS. THE COLD FRONT HAS MADE IT HALF WAY THROUGH KANSAS AS OF
THIS ISSUANCE AND WILL CONTINUE TO MOVE SOUTHWARD THROUGH OKLAHOMA
DURING THE DAY. WINDS ARE GUSTY BEHIND THE FRONT WITH LOW TO MID
LEVEL CLOUDS. LOOKING WEST...ANOTHER DISTURBANCE IS LOCATED OVER
MID-CALIFORNIA/NEVADA/UTAH. THIS WILL BE THE WEATHER MAKER FOR THE
FIRST PART OF THE WEEK.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 332 AM CDT MON APR 1 2013
THIS PERIOD WILL BE RAINY OFF AND ON AND COOLER FOR MUCH OF SOUTHERN
KANSAS. THE LATEST GUIDANCE...NAM/GFS/ECMWF AND HRRR INDICATE
PRECIPITATION DEVELOPING ACROSS SOUTH CENTRAL KANSAS AROUND MID
AFTERNOON TODAY BEFORE SPREADING EAST ACROSS SOUTHERN KANSAS THROUGH
THE DAY AND OVERNIGHT. PRECIPITATION WILL DEVELOP NEAR THE 850MB
FRONT. THE UPPER LEVEL WAVE OVER THE WEST WILL CONTINUE TO MOVE
TOWARDS THE AREA...ENHANCING UPPER LEVEL SUPPORT. THE 850MB FRONT
WILL REMAIN STATIONARY...KEEPING THE PRECIPITATION CHANCES THROUGH
WEDNESDAY. NOT EXPECTING THUNDER WITH THIS EVENT WITH VERY LOW
MUCAPE VALUES...BUT CANNOT RULE OUT AN ISOLATED LIGHTNING STRIKE.
THIS PERIOD WILL REMAIN COOLER...AS THE COLD FRONT USHERED IN
UNSEASONABLY COOL AIR. WITH COLD AIR ADVECTION...CLOUDY SKIES AND
RAIN...TEMPERATURES WILL BE 10 TO 20 DEGREES BELOW NORMAL. TUESDAY
LOOKS TO BE THE COOLEST DAY WITH CLOUD COVER AND RAIN.
BILLINGS
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 332 AM CDT MON APR 1 2013
BY THURSDAY THE UPPER LEVEL DISTURBANCE THAT WILL IMPACT THE AREA
FOR THE FIRST HALF OF THE FORECAST WILL FINALLY BE ON ITS WAY EAST.
SURFACE HIGH PRESSURE WILL MOVE OVERHEAD THURSDAY WITH CLEARING
SKIES IN THE SUBSIDENCE ZONE OF THE UPPER WAVE. THIS WILL ALLOW
TEMPERATURES TO WARM BACK INTO THE UPPER 50S AND LOW 60S.
TEMPERATURES WILL CONTINUE TO INCREASE FOR FRIDAY AND SATURDAY AHEAD
OF THE NEXT SYSTEM. LEE CYCLOGENESIS WILL DEEPEN AHEAD OF THE NEXT
WAVE...WITH STRONG WARM AIR ADVECTION AND MIXING...TEMPS WILL REACH
BACK INTO THE 60S AND 70S. THE NEXT DISTURBANCE WILL MOVE ACROSS
THE NORTHERN PLAINS...DRAGGING A COLD FRONT ACROSS THE REGION. THE
MAIN LIFT ASSOCIATED WITH THIS FRONT WILL BE ACROSS THE NORTHERN
PLAINS...SO NOT EXPECTING MUCH IN THE WAY OF PRECIPITATION ALONG THE
FRONTAL BOUNDARY AND HAVE LEFT THE FORECAST DRY FOR SATURDAY AND
SUNDAY. TEMPERATURES BEHIND THE FRONT WILL ONLY DECREASE SLIGHTLY.
ANOTHER WAVE WILL APPROACH FOR THE VERY END OF THE FORECAST AND
PRECIPITATION MAY RETURN FOR SUNDAY AND INTO THE EARLY PART OF NEXT
WEEK. WILL CONTINUE TO WATCH THIS PERIOD AS THE FORECAST EVOLVES AS
THE TIME PERIOD NEARS.
BILLINGS
&&
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
ISSUED AT 1208 AM CDT MON APR 1 2013
AT 05Z A STRONG ALMOST E-W ORIENTED COLD FRONT THAT HAS BEEN MOVING S
THIS EVENING ENTERED NRN KS ~03Z & SHOULD STILL ARRIVE KRSL & KSLN 08Z.
THE COLD FRONT SHOULD REACH SC & SE KS ~10Z. DURING FRONTAL PASSAGE
WINDS THAT ARE VARIABLE <7KTS WILL QUICKLY & ABRUPTLY SHIFT TOWARD THE
NE & INCREASE TO A SUSTAINED ~17KTS/20MPH WITH GUSTS ~25KTS. POST-COLD
FRONTAL ~1,500FT STRATOCU WILL SPREAD OVER PRIMARILY KSLN ~11Z BUT ONLY
LAST TIL ~15Z. NE WINDS WILL GRADUALLY DIMINISH IN A N-S MANNER AS HIGH
PRESSURE SPREADS S/SE FROM THE DAKOTAS TO NEBRASKA.
ES
&&
.FIRE WEATHER...
ISSUED AT 332 AM CDT MON APR 1 2013
VERY LITTLE IN THE WAY OF FIRE CONCERN FOR MUCH OF THE FORECAST.
LIGHT WINDS AND PRECIPITATION WILL KEEP GRASSLAND FIRE DANGER LOW.
WITH STRONGER WINDS AND WARMER TEMPERATURES ON FRIDAY...GRASSLAND
FIRE DANGER WILL BE VERY HIGH.
BILLINGS
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 51 35 43 35 / 40 60 50 30
HUTCHINSON 50 33 45 32 / 30 40 40 20
NEWTON 51 32 43 31 / 30 30 30 20
ELDORADO 51 33 44 33 / 30 40 40 20
WINFIELD-KWLD 53 36 42 36 / 40 70 70 40
RUSSELL 51 30 48 30 / 20 30 20 10
GREAT BEND 50 31 46 31 / 20 30 30 20
SALINA 52 31 50 33 / 20 20 10 10
MCPHERSON 51 32 46 32 / 30 30 20 10
COFFEYVILLE 55 37 44 36 / 40 60 70 40
CHANUTE 53 34 44 34 / 30 30 30 10
IOLA 52 33 45 33 / 30 20 20 10
PARSONS-KPPF 53 35 44 35 / 30 50 50 30
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS GAYLORD MI
523 AM EDT MON APR 1 2013
.SYNOPSIS...
ISSUED AT 422 AM EDT MON APR 1 2013
A SYSTEM IN QUEBEC IS BRINGING COLD AIR AND NORTHWEST WINDS TO THE
STATE TODAY. THE COLDER AIR IS PRODUCING LAKE EFFECT SNOW SHOWERS
WHICH WILL PERSIST OVER NORTHERN MICHIGAN THROUGH TUESDAY. THE MOST
PERSISTENT SNOW SHOWERS WITH THE BEST CHANCE OF ACCUMULATION WILL BE
IN THE TYPICAL SNOW BELTS OF NORTHWEST LOWER AND EAST UPPER
MICHIGAN.
&&
.UPDATE...
ISSUED AT 519 AM EDT MON APR 1 2013
CHANGES THIS HOUR: BAND HESITATED LONG ENOUGH FOR ME...AND HAVE
ISSUED A WINTER WEATHER ADVISORY FOR 4 OF THE BIG 5 /EXCLUDED
KALKASKA/ THROUGH NOON. RADAR ESTIMATES HAVE REACHED 2-3" IN
SPOTS...WITH BIG FLUFFY FLAKES FALLING HERE AT THE OFFICE
INDICATING 20:1 RATIOS LOOK GOOD. WINDS AMPLE TO BLOW THIS SNOW
AROUND AS WELL. EXPECT 2-4 OVER THE NEXT FEW HOURS AS BAND STARTS
TO EDGE EAST FROM ITS CURRENT LOCATION...BEFORE LIKELY BREAKING UP
BY LATE MORNING.
NO OTHER CHANGES ATTM.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 422 AM EDT MON APR 1 2013
HIGH IMPACT WEATHER POTENTIAL: GALE FORCE WIND GUSTS POSSIBLE ALL
MARINE WATERS THROUGH TODAY. SNOW/BLOWING SNOW WILL BRING SOME
SLICK TRAVEL AND REDUCED VISIBILITIES TO THE SNOWBELTS OF EASTERN
UPPER/NORTHERN LOWER...WITH SNOW SHOWERS REACHING ALL OTHER LOCALES
AS WELL.
OVERVIEW: WISHING THE EARLY MORNING WATER VAPOR IMAGERY WAS AN APRIL
FOOLS JOKE THIS MORNING AS IMPRESSIVE TROUGH CARVES ITSELF OUT OVER
THE GREAT LAKES REGION. PICKLE LAKE /ONTARIO/ 00Z RAOB SHOWS -42C AT
H5...-25C AT H7 AND -20C AT H8...AN ARCTIC AIRMASS INDEED WITH SURFACE
TEMPS UPSTREAM OF THE GREAT LAKES IN THE LOWER TEENS AND DEWPOINTS
FALLING TO NEAR ZERO. WITH SUBSTANTIAL DOWNSTREAM BLOCKING IN PLACE
FROM GREENLAND SOUTH AND EAST...THE DEVELOPING LONGWAVE TROUGH
OVERHEAD WILL BE IN NO HURRY TO DEPART...WITH ITS IMPACTS DOMINATING
THE SHORT TERM PORTION OF THE FORECAST.
THROUGH DAYBREAK: APX WSR-88D SHOWING LAKE EFFECT SNOW GETTING IT/S
ACT TOGETHER OVER NORTHERN LOWER...WITH PRIMARY BAND FROM ACB-GOV
STRENGTHENING WITH GOOD LAKE SUPERIOR CONNECTION. EXPECT THIS TREND
TO CONTINUE THROUGH DAYBREAK WITH AN INCH OR TWO OF SNOW POSSIBLE
OVER THE BIG 5 OF NW LOWER. WILL COVER THIS BAND WITH AN SPS FOR A
QUICK 1-2 INCHES WHICH WILL LIKELY IMPACT THE MONDAY MORNING
COMMUTE.
WINDS REMAIN QUITE BRISK AS 6MB/6HR PRESSURE RISE CENTER OVER
NORTHERN LAKE SUPERIOR SLIDES SOUTH AND EAST...WITH 15-25 MPH WINDS
THROUGHOUT NORTHERN MICHIGAN...GUSTING AS HIGH AS 35 MPH NEAR THE
COASTS.
TODAY: WITH THE CORE OF THE H5 LOW PUSHING FROM JUST NORTH OF THE
SOO EARLY THIS MORNING TO SOUTHWESTERN QUEBEC BY THSI EVENING...OUR
FLOW ALOFT WILL BACK SLIGHTLY AS THE COLDEST AIR ALOFT MAKES ITS
CLOSEST APPROACH. T8 AROUND -17C WITH WHAT LOOKS TO BE ROBUST
LLEVEL MOISTURE /SEE FOG PRODUCT IMAGERY SHOWING ALL KINDS OF
MOISTURE JUST WEST OF THE H5 LOW CENTER /AND THUS...OVERHEAD
TODAY/. THIS SPELLS CONTINUED LAKE EFFECT SNOW SHOWERS UNDER STRONG
NW WINDS. ALL HIGH RESOLUTION GUIDANCE CONTINUES TO SHOW A DOMINANT
BAND TO START THE DAY...WITH THE HRRR LOOKING TO CAPTURE IT/S
LOCATION BEST /FURTHER WEST THAN THE RAP AND LOCAL WRF/. GIVEN THAT
WE ALREADY HAVE A BAND OF THIS NATURE...SEE NO REASON TO DISAGREE
WITH THE GUDIANCE SUGGESTION...WHICH SHOWS THIS BAND STARTING THE
DAY CENTERED FROM CVX-ACB-GOV PUSHING EAST GIVEN THE AFOREMENTIONED
BACKING FLOW...WITH SOMEWHAT LIGHTER SHSN SURROUNDING IT. THE BAND
LOOKS TO BE QUITE MOBILE THROUGH THE MORNING BEFORE CAPE/SHEAR
NOMOGRAM SUGGESTS THAT BY LATE MORNING IT WIL BEGIN TO BREAK UP AS
OVERLAND INSTABILITY STRENGTHENS. THIS BACKING FLOW SHOULD HELP GET
WESTERN CHIPPEWA/MACKINAC BACK INTO THE ACTION DURING THE DAY AS
WELL.
SNOWFALL: MOBILE SNOWBAND WILL KEEP A LID ON SNOW AMOUNTS...BUT
COULD SEE 1-3" FOR THE DAY TODAY OVER THE NW SNOWBELTS...WITH MOST
OF THIS FALLING BEFORE ACTIVITY BECOMES MORE CELLULAR THIS
AFTERNOON.
WHILE WE LOSE HELP FROM ANY ISALLOBARIC COMPONENT TO THE LLEVEL
WINDS TODAY...H9 WINDS 25-30KTS AND AMPLE LLEVEL MIXING SUGGEST
WINDS 15-25 MPH WINDS WITH GUSTS WELL INTO THE 30S...PARTICULARLY
NEAR THE LAKESHORES AND OVER EASTERN UPPER.
TEMPS WILL BE VERY SLOW TO CLIMB WITH T9 AROUND -10C SUGGESTING MID
20S /SOME 20F BELOW NORMAL/ WILL BE ABOUT ALL WE CAN MUSTER. WITH
THE STRONG WINDS...WIND CHILLS WILL REMAIN IN THE TEENS THROUGH THE
DAY.
HEADLINES: WILL GO AHEAD AND DROP WINTER WEATHER ADVISORY FOR
CHIPPEWA GIVEN LOCATION OF SNOWFALL ACTIVITY WELL WEST OF COUNTY
WITH ACCUMS THUS FAR NOT SUFFICIENT TO WARRANT THE HEADLINE.
AS DISCUSSED ABOVE...HEAVIEST SNOW IS NOW OVER THE BIG 5 IN NW
LOWER...AND WILL MONITOR FOR POTENTIAL HEADLINE THROUGH
DAYBREAK...ALTHOUGH EXPECTATION IS THAT THE BAND WILL BEGIN TO
MOVE...REDUCING THE THREAT OF SIGNIFICANT ACCUMS.
TONIGHT: SYNOPTIC MOISTURE BEGINS TO SLOWLY ERODE WITH TEMPS ALOFT
STEADY OR JUST SLIGHTLY WARING UNDER A FAIRLY STEADY 300-310 FLOW
REGIME. SOME RESIDUAL LAND-BASED CAPE CONTINUES THROUGH THE
OVERNIGHT WHICH MAY NOT FULLY ALLOW THE LAKE EFFECT TO RE-SOLIDIFY
INTO BANDS. SHSN WILL CERTAINLY CONTINUE...HOWEVER...WITH
ADDITIONAL LIGHT ACCUMULATIONS LIKELY. INHERITED ACCUMS OF 1-2
INCHES /PERHAPS 3 OVER WESTERN CHIPPEWA/ LOOK REASONABLE AND HAVE NO
COMPELLING REASON TO DEVIATE SIGNIFICANTLY.
CLOUDS WILL LIKELY KEEP TEMPERATURES FROM FALLING ALL THAT FAR...
GENERALLY IN THE UPPER TEENS TO AROUND 20.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 422 AM EDT MON APR 1 2013
TUESDAY...AS THE SFC HIGH BEGINS TO MOVE INTO THE REGION, THE 850 MB
TEMPERATURES BEGIN TO WARM SLIGHTLY, JUST ENOUGH THAT WE MAY LOSE
THE INSTABILITY NEEDED FOR THE LES. THE MOISTURE IN THE 850-700 MB
LAYER FALLS OFF TO BELOW 60% ON ALL THE MODELS SO WOULD EXPECT LIGHT
SNOW AND FLURRIES. ALTHOUGH WILL HAVE LIKELY POPS SINCE MEASURABLE
SNOW IS EXPECTED FROM THIS PATTERN IN THE MORNING. BY THE AFTERNOON,
THE MOISTURE CONTINUES TO FALL OFF IN THE 850-700 MB LAYER. THE ONE
THING THAT I HAVE NOTICED ABOUT THESE LATE SEASON LES EVENTS IS THAT
IT HAS BECOME HARD FOR THE LOWER END OF THE SOUNDINGS TO SATURATE.
THIS HAS BEEN LEADING TO INVERTED V SOUNDINGS AND REALIZING LESS
SNOW THAN WE WOULD HAVE EVEN A MONTH AGO DURING THE AFTERNOON.
TUESDAY NIGHT...AS THE RIDGE BUILDS INTO THE REGION, THE DRIER AIR
REALLY BEGINS TO OVERWHELM THE REGION, SHUTTING OFF MOST OF THE SNOW
LEAVING ONLY CHANCE POPS IN THE EVENING IN E UPPER, WHILE N LOWER
WILL BE DRY ENOUGH TO NOT HAVE ANY SNOW.
WEDNESDAY...HIGH PRESSURE AT THE SFC AND 500 MB RIDGE MOVES THROUGH
THE REGION SO THAT WE WILL REMAIN DRY FOR THE DAY. OVERNIGHT, A COLD
FRONT AND 500 MB SHORTWAVE TROUGH MOVE INTO THE REGION. THE GFS IS A
LITTLE FASTER THAN THE ECMWF AND NAM. WILL HOLD OFF THE SNOW BY
ALLOWING IT TO JUST TOUCH E UPPER BY 12Z.
EXTENDED (THURSDAY THROUGH SUNDAY)...THURSDAY, THE MODELS DRY THINGS
OUT WITH THE FRONTAL PASSAGE DURING THE DAY. SO WILL HAVE CHANCE
POPS WITH A MIX OF THE RAIN AND SNOW IN E UPPER AND JUST RAIN IN N
LOWER. WITH THE SFC TEMPERATURES IN THE 40S, WOULD NOT BE SURPRISED
IF THIS TURNS OUT TO BE FLURRIES AND SPRINKLES. FRIDAY, THE HIGH
BUILDS INTO THE UPPER GREAT LAKES REGION AND DRIES THINGS OUT AGAIN.
SO DRY WEATHER WILL BE EXPECTED. SATURDAY, THE WARM FRONT WILL BE
MOVING INTO THE REGION. THE ECMWF HAS THE WARM AIR INTO E UPPER SO
THAT IT COULD BE ALL RAIN, WHILE THE GFS HAS IT PLACED A LITTLE
SOUTH. PUT THE DIVIDING LINE AT THE STRAITS SINCE THAT SEEMED TO BE
THE MIDDLE GROUND. WHICH WOULD CONTINUE THROUGH THE NIGHT AS THE
SYSTEM MOVES EAST. SUNDAY, THE LOW MOVES EAST OF THE REGION AND THE
COLD AIR MOVES BACK IN ALLOWING FOR A CHANGE OVER TO SNOW. THE GFS
DRIES THINGS OUT. WILL LEAN TOWARD THE ECMWF WHICH WOULD BE THE
PESSIMISTIC FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 128 AM EDT MON APR 1 2013
SUMMARY: STRONG NORTHWEST FLOW WILL CONTINUE THROUGH THE UPCOMING
TAF PERIOD...WITH LAKE EFFECT SNOW SHOWERS OCCASIONALLY IMPACTING
THE TERMINALS.
RESTRICTIONS: EXPECT VFR CONDITIONS TO DOMINATE MOST OF THE TAF
PERIOD...WITH HEAVIEST LES OVERNIGHT TONIGHT REMAINING BETWEEN PLN
AND TVC. BANDING LOOKS TO TARGET PLN SOMETIME LATER THIS
MORNING/EARLY AFTERNOON...ALTHOUGH IT WILL LIKELY BE BREAKING UP
INTO MORE CELLULAR ACTIVITY BY THIS TIME. SO...WILL ONLY INCLUDE
A PERIOD OF MVFR WITH THIS TAF PACKAGE...AND AWAIT LATER TRENDS TO
POTENTIALLY ADD A SHORT PERIOD OF IFR.
AT THE OTHER TERMINALS...WHILE A QUICK DROP TO MVFR IN SHSN IS
POSSIBLE...THERE IS LOW CONFIDENCE IN TIMING...SO WILL FOLLOW TRENDS
THROUGH THE REMAINDER OF THE OVERNIGHT BEFORE ADDING ANY TEMPOS AT
TVC/APN. AT THIS TIME...MBL LOOKS TO REMAIN VFR.
WINDS: NORTHWEST WINDS 14G22KTS TONIGHT WILL CONTINUE 18G28KTS FOR
THE DAY ON MONDAY BEFORE DIMINISHING TO 10-15KTS MONDAY NIGHT.
&&
.MARINE...
ISSUED AT 422 AM EDT MON APR 1 2013
SUMMARY: STRONG NORTHWESTERLY WINDS TO CONTINUE THROUGH TUESDAY AS
LOW PRESSURE MOVES INTO EASTERN CANADA. HIGH PRESSURE ARRIVES BY
MIDWEEK WITH QUIETER CONDITIONS EXPECTED.
HEADLINES: MARGINAL GALES WILL BE ALLOWED TO CONTINUE ALL ZONES
THROUGH THIS EVENING. SMALL CRAFTS WILL CERTAINLY BE NEEDED BEYOND
THIS...WITH ADDITIONAL GALE FORCE GUSTS POSSIBLE AGAIN
TUESDAY...PARTICULARLY FOR NORTHWESTERLY FLOW FAVORED REGIONS.
BEYOND THIS...NEXT ROUND OF SMALL CRAFTS LOOKS LIKELY BY WEDNESDAY
NIGHT OVER LAKE MICHIGAN AS SOUTHWESTERLY WINDS STRENGTHEN AHEAD OF
NEXT APPROACHING SYSTEM.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL NOON EDT TODAY FOR MIZ019-021-022-
028.
LH...GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LHZ345>349.
LM...GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LMZ323-341-342-
344>346.
LS...GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LSZ321-322.
&&
$$
UPDATE...ARNOTT
SYNOPSIS...JL
SHORT TERM...ARNOTT
LONG TERM...JL
AVIATION...ARNOTT
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
444 AM EDT MON APR 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 440 AM EDT MON APR 1 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF
CENTERED FM HUDSON BAY INTO THE GRT LKS DOWNSTREAM OF UPR RDG OVER
WRN CANADA. 00Z H5/H85 TEMPS ARE AS LO AS -42C/-20C AT THE CORE OF
THE COLDEST AIR AT YPL. CYC NNW FLOW ON THE WRN FLANK OF LO PRES
MOVING SLOWLY E INTO QUEBEC IS DRAWING THIS VERY COLD AIR SWD INTO
THE UPR LKS OVER THE RELATIVELY WARM WATERS OF LAKE SUP...WITH THE
RESULT NMRS LES BANDS AS SHOWN ON MQT RADAR. WELL DEFINED AXIS OF
COLDER CLD TOPS AS SHOWN ON IR STLT IMAGERY IS PRESENT OVER THE E
HALF OF THE LK AND ASSOCIATED WITH FAIRLY SHARP H7-3 QVECTOR CNVGC.
THIS AXIS OF DEEPER MSTR HAS CAUSED SOME ENHANCEMENT TO THE SHSN.
THE HEAVIEST BAND IS STREAMING INTO CENTRAL ALGER COUNTY/SCHOOLCRAFT
COUTY...WITH SOME RETURNS AOA 30 DBZ AT 06Z. SN UNDER THIS BAND IS
LIKELY FALLING AT THE RATE OF AT LEAST AN INCH/HR GIVEN FAVORABLE
LOCATION OF UVV MAX WITHIN DGZ AS SHOWN BY PROFILE FM LOCAL HI RES
MODEL. SINCE THE COLDER CLD TOPS ARE TENDING TO DRIFT TO THE E AND
DRIER LLVL AIR SHOWN ON THE 00Z INL RAOB IS PRESSING TO THE E...
DROPPING THE SFC DEWPT TO NEAR 7F AT IWD AT 06Z...THE INTENSITY OF
THE LES W OF MQT HAS TENDED TO DIMINISH OVER TIME PER RADAR TRENDS
EVEN THOUGH IR STLT IMAGERY INDICATES SOME LES BANDS OVER THE W HALF
OF THE LK THAT HAVE FORMED IN THE PRESENCE OF NOCTURNAL COOLING THAT
IS SO IMPORTANT TO ACHIEVE BETTER LES BAND STRUCTURE THIS TIME OF
YEAR. NW WINDS ARE STILL GUSTING AS HI AS 40 KTS AT STANNARD ROCK AS
OF 06Z...BUT PASSAGE OF PRES RISE CENTER TRAILING THE SFC LO INTO
ONTARIO E OF LK SUP HAS CAUSED A SLOW DIMINISHING TREND TO THE WINDS.
MAIN FCST CONCERNS THIS PACKAGE ARE LES TRENDS/GOIND HEADLINES.
TODAY...MODELS INDICATE UPR TROF AXIS WL DRIFT SLOWLY TO THE E. AREA
OF DEEP LYR QVECTOR CNVGC ENHANCING COMMA HEAD/COLDER CLD TOPS NOW
OVER THE E HALF OF LK SUP IS PROGGED TO DRIFT INTO ONTARIO IN THE
09Z-12Z TIME FRAME. IN CONCERT WITH THE ARRIVAL OF SOME DRYING FM
THE W...LES INTENSITY/COVERAGE SHUD DIMINISH BY SUNRISE. BUT GIVEN
PERSISTENCE OF SGNFT BAND OVER CENTRAL ALGER COUNTY INTO NRN
SCHOOLCRAFT COUNTY IN PERSISTENT NNW FLOW THRU THE EARLY MRNG
HRS...FVRBL SN/WATER RATIOS UNDER COLDEST H85 TEMPS...AND HIER RES
MODEL FCSTS THAT SHOWING FAIRLY HI QPF THRU 18Z WITH DEEPER MSTR
PERSISTING LONGEST IN THAT AREA CLOSER TO DEPARTING LO...OPTED TO
UPGRADE GOING ADVY FOR THOSE ZONES TO AN LES WARNING. OTRW...RISING
H5 HGTS/DEEP LYR QVECTOR CNVGC/SUBSIDENCE IN THE PRESENCE OF DIURNAL
HEATING THAT TENDS TO DISRUPT THE LES PROCESS IN EARLY SPRING SHOULD
CAUSE THE LES BANDS TO WEAKEN AND TRANSITION TO A MORE BLOTCHY
APPEARANCE. SLOWLY BACKING FLOW TOWARD MORE WNW BY THE LATE IN THE
DAY WL ALSO CAUSE AREA OF HEAVIER SHSN TO SHIFT. ADDITIONAL SN
AMOUNTS OVER THE W WL BE LIGHT WITH LLVL DRY AIR HAVING A MORE SGNFT
IMPACT THERE AND MODELS HINTING TOWARD A TRANSITION TO LLVL ACYC
FLOW IN THE AFTN.
TONIGHT...STEADILY RISING HGTS/DEEP LYR QVECTOR CNVGC THAT DROPS
FCST INVRN BASE TOWARD 5-6K FT OVER EVEN THE E SUG LES INTENSITY WL
BE SOMEWHAT DIMINISHED EVEN THOUGH PERSISTENT NW FLOW/H85 TEMPS IN
THE -16 TO -17C RANGE WL ALLOW FOR CONTINUED WDSPRD LES...ESPECIALLY
AFTER MID EVNG WHEN IMPACTS OF DAYTIME HEATING WOULD TEND TO
SUBSIDE. WITH INVRN BASE OVER THE W FALLING TO ARND 4K FT OVER THE
W...SHSN INTENSITY IN THIS AREA WL BE WEAKER WITH SHORTER FETCH/LESS
MODERATION OF UPSTREAM AIRMASS. BUT STILL WENT WITH LIKELY POPS
GIVEN FVRBL NW FLOW/OVERWATER INSTABILITY/NOCTURNAL COOLING THAT WL
ALLOW LES BANDS TO REDEVELOP.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 440 AM EDT MON APR 1 2013
DESPITE ADEQUATE DELTA TS PERSISTING INTO TUESDAY FOR LAKE
EFFECT...SFC-H85 FLOW WILL BECOME INCREASINGLY ANTICYCLONIC THROUGH
THE DAY. IN ADDITION...INVERSION HEIGHTS BEGIN TO FALL OFF
SIGNIFICANTLY BELOW 5KFT. THUS...EXPECT OVERALL COVERAGE AND
INTENSITY OF LAKE EFFECT TO BE ON THE WANE AS THE DAY PROGRESSES.
TEMPERATURES WILL REMAIN WELL BELOW NORMAL WITH A SIGNIFICANT AMOUNT
OF CLOUDINESS DOWNWIND OF LAKE SUPERIOR.
LAKE CLOUDS AND EVEN A FEW FLURRIES WILL PERSIST INTO THE MORNING
WEDNESDAY OVER THE EAST. AS SURFACE RIDGE AXIS MOVES OVERHEAD
THROUGH THE DAY EXPECT SKIES TO BECOME MOSTLY SUNNY AREA WIDE.
TEMPERATURES SHOULD REBOUND BACK ABOVE FREEZING AND EVEN APPROACH 40
ACROSS THE WEST WITH WARM ADVECTION INCREASING DURING THE AFTERNOON
AND MORE SUNSHINE.
MODELS COMING INTO BETTER AGREEMENT WITH THE TIMING OF THE NEXT
SHORTWAVE AND SFC TROUGH EXPECTED TO MOVE ACROSS THE AREA WED
NIGHT/THU. THE TREND HAS BEEN TOWARD QUICKER MOVEMENT WITH THE TROUGH.
SYSTEM IS FAIRLY MOISTURE STARVED...SO DESPITE PRECIP TYPE BEING A
CHALLENGE BETWEEN RAIN AND SNOW...AMOUNTS WILL BE LIGHT ENOUGH TO BE
PRETTY INSIGNIFICANT. COLD ADVECTION BEHIND THE TROUGH SHOULD PUSH
85H TEMPS BACK DOWN TO THE -10 TO -14C RANGE BY FRIDAY. PROBABLY NOT
QUITE COLD ENOUGH FOR LAKE EFFECT THIS TIME AROUND...BUT COLDER AIR
WILL KEEP DAYTIME TEMPS BELOW AVERAGE ONLY IN THE 30S.
FORECAST FOR NEXT WEEKEND STILL PRETTY CHALLENGING...BUT MODELS
SHOWING SOME SIGNS THAT THEY ARE TRYING TO CONVERGE ON A MORE
PROBABLE OUTCOME. SHORTWAVE ENERGY AND ASSOCIATED SURFACE LOW MOVING
OUT OF THE PLAINS LOOKING LIKE THEY MAY NOW TRACK THROUGH THE LOWER
LAKES WHICH WOULD STILL RESULT IN SOME LIGHT SNOWFALL ACROSS
SOUTHERN AREAS SATURDAY INTO SUNDAY BUT SPARE THE AREA FROM A MORE
SIGNIFICANT STORM. IT IS STILL SOMETHING TO KEEP AN EYE ON AS WE
HEAD THROUGH THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 129 AM EDT MON APR 1 2013
INCREASINGLY COLDER AIR MOVING ACROSS LAKE SUPERIOR IN NW FLOW WILL
SUSTAIN PERIODS OF LAKE EFFECT SNOW SHOWERS AND MVFR CONDITIONS INTO
MONDAY AT ALL 3 TAF SITES. GUSTY NW WINDS TO 25 KTS AT TIMES COULD
ALSO CONTRIBUTE TO LOWER IFR VSBYS IN SNOW AND BLOWING SNOW...MAINLY
AT MORE EXPOSED KCMX SITE. WINDS BACKING A BIT MORE TO THE
WNW...SHOULD REDUCE CHCS FOR LAKE EFFECT SNOW SHOWERS AT KSAW BY
MONDAY AFTERNOON...PERHAPS EVEN LEADING TO VFR CONDITIONS BY MONDAY
EVENING. ARRIVAL OF DRIER NEAR SFC AIR SHOWN ON THE 00Z INL RAOB WILL
ALSO BRING ABOUT LONG PERIODS OF VFR CONDITIONS AT IWD. THE
COMBINATION OF THE DRYING AND DAYTIME HEATING THIS AFTN WILL DIMINISH
THE LES INTENSITY AT CMX AS WELL.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 440 AM EDT MON APR 1 2013
AS LO PRES OVER SE CANADA CONTINUES TO THE E AND THE PRES GRADIENT
WEAKENS...EXPECT NW WINDS TO SLOWLY DIMINISH AND BELOW GALE FORCE
OVER THE CENTRAL BY MID MORNING...SO HASTENED THE ENDING OF THE GALE
WARNINGS FOR THIS AREA. ALTHOUG NW GALES TO 35 KTS WILL CONTINUE
LONGER OVER THE E INTO THIS EVENING...ENDED THE GALES FOR THAT AREA
EARLIER AS WELL. WINDS/WAVES WILL BE SUFFICIENT TO MAINTAIN FREEZING
SPRAY OVER AT LEAST THE E HALF THRU TONIGHT.
WINDS WILL REMAIN PRETTY GUSTY UP TO 30 KNOTS OVER THE EASTERN LAKE
THROUGH THE DAY ON TUESDAY...BUT AS SURFACE RIDGE AXIS PUSHES IN
FROM THE WEST PRESSURE GRADIENT WILL RELAX AND WINDS WILL DIMINISH
DURING THE EVENING. UNTIL THAT TIME...FREEZING SPRAY SHOULD CONTINUE
ACROSS THE EASTERN LAKE. AFTER A BRIEF RESPITE ON
WEDNESDAY...SOUTHWESTERLY WINDS UP TO 25 KNOTS AHEAD OF THE NEXT
TROUGH CROSSING THE LAKE WILL INCREASE WEDNESDAY NIGHT INTO EARLY
THURSDAY BEFORE SHIFTING TO THE NORTHWEST DURING THE DAY THURSDAY
INTO THURSDAY NIGHT. WINDS FOR FRIDAY INTO NEXT WEEKEND SHOULD BE
BELOW 20 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR MIZ007.
LAKE EFFECT SNOW WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR
MIZ006-085.
LAKE SUPERIOR...
GALE WARNING UNTIL 2 AM EDT TUESDAY FOR LSZ266-267.
GALE WARNING UNTIL NOON EDT TODAY FOR LSZ265.
GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LSZ264.
GALE WARNING UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ249.
GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR LSZ244-245.
GALE WARNING UNTIL 6 AM EDT TUESDAY FOR LSZ250-251.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...MZ
AVIATION...VOSS/KC
MARINE...KC/MZ
AREA FORECAST DISCUSSION
NWS GAYLORD MI
430 AM EDT MON APR 1 2013
.SYNOPSIS...
ISSUED AT 422 AM EDT MON APR 1 2013
A SYSTEM IN QUEBEC IS BRINGING COLD AIR AND NORTHWEST WINDS TO THE
STATE TODAY. THE COLDER AIR IS PRODUCING LAKE EFFECT SNOW SHOWERS
WHICH WILL PERSIST OVER NORTHERN MICHIGAN THROUGH TUESDAY. THE MOST
PERSISTENT SNOW SHOWERS WITH THE BEST CHANCE OF ACCUMULATION WILL BE
IN THE TYPICAL SNOW BELTS OF NORTHWEST LOWER AND EAST UPPER
MICHIGAN.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 422 AM EDT MON APR 1 2013
HIGH IMPACT WEATHER POTENTIAL: GALE FORCE WIND GUSTS POSSIBLE ALL
MARINE WATERS THROUGH TODAY. SNOW/BLOWING SNOW WILL BRING SOME
SLICK TRAVEL AND REDUCED VISIBILITIES TO THE SNOWBELTS OF EASTERN
UPPER/NORTHERN LOWER...WITH SNOW SHOWERS REACHING ALL OTHER LOCALES
AS WELL.
OVERVIEW: WISHING THE EARLY MORNING WATER VAPOR IMAGERY WAS AN APRIL
FOOLS JOKE THIS MORNING AS IMPRESSIVE TROUGH CARVES ITSELF OUT OVER
THE GREAT LAKES REGION. PICKLE LAKE /ONTARIO/ 00Z RAOB SHOWS -42C AT
H5...-25C AT H7 AND -20C AT H8...AN ARCTIC AIRMASS INDEED WITH SURFACE
TEMPS UPSTREAM OF THE GREAT LAKES IN THE LOWER TEENS AND DEWPOINTS
FALLING TO NEAR ZERO. WITH SUBSTANTIAL DOWNSTREAM BLOCKING IN PLACE
FROM GREENLAND SOUTH AND EAST...THE DEVELOPING LONGWAVE TROUGH
OVERHEAD WILL BE IN NO HURRY TO DEPART...WITH ITS IMPACTS DOMINATING
THE SHORT TERM PORTION OF THE FORECAST.
THROUGH DAYBREAK: APX WSR-88D SHOWING LAKE EFFECT SNOW GETTING IT/S
ACT TOGETHER OVER NORTHERN LOWER...WITH PRIMARY BAND FROM ACB-GOV
STRENGTHENING WITH GOOD LAKE SUPERIOR CONNECTION. EXPECT THIS TREND
TO CONTINUE THROUGH DAYBREAK WITH AN INCH OR TWO OF SNOW POSSIBLE
OVER THE BIG 5 OF NW LOWER. WILL COVER THIS BAND WITH AN SPS FOR A
QUICK 1-2 INCHES WHICH WILL LIKELY IMPACT THE MONDAY MORNING
COMMUTE.
WINDS REMAIN QUITE BRISK AS 6MB/6HR PRESSURE RISE CENTER OVER
NORTHERN LAKE SUPERIOR SLIDES SOUTH AND EAST...WITH 15-25 MPH WINDS
THROUGHOUT NORTHERN MICHIGAN...GUSTING AS HIGH AS 35 MPH NEAR THE
COASTS.
TODAY: WITH THE CORE OF THE H5 LOW PUSHING FROM JUST NORTH OF THE
SOO EARLY THIS MORNING TO SOUTHWESTERN QUEBEC BY THSI EVENING...OUR
FLOW ALOFT WILL BACK SLIGHTLY AS THE COLDEST AIR ALOFT MAKES ITS
CLOSEST APPROACH. T8 AROUND -17C WITH WHAT LOOKS TO BE ROBUST
LLEVEL MOISTURE /SEE FOG PRODUCT IMAGERY SHOWING ALL KINDS OF
MOISTURE JUST WEST OF THE H5 LOW CENTER /AND THUS...OVERHEAD
TODAY/. THIS SPELLS CONTINUED LAKE EFFECT SNOW SHOWERS UNDER STRONG
NW WINDS. ALL HIGH RESOLUTION GUIDANCE CONTINUES TO SHOW A DOMINANT
BAND TO START THE DAY...WITH THE HRRR LOOKING TO CAPTURE IT/S
LOCATION BEST /FURTHER WEST THAN THE RAP AND LOCAL WRF/. GIVEN THAT
WE ALREADY HAVE A BAND OF THIS NATURE...SEE NO REASON TO DISAGREE
WITH THE GUDIANCE SUGGESTION...WHICH SHOWS THIS BAND STARTING THE
DAY CENTERED FROM CVX-ACB-GOV PUSHING EAST GIVEN THE AFOREMENTIONED
BACKING FLOW...WITH SOMEWHAT LIGHTER SHSN SURROUNDING IT. THE BAND
LOOKS TO BE QUITE MOBILE THROUGH THE MORNING BEFORE CAPE/SHEAR
NOMOGRAM SUGGESTS THAT BY LATE MORNING IT WIL BEGIN TO BREAK UP AS
OVERLAND INSTABILITY STRENGTHENS. THIS BACKING FLOW SHOULD HELP GET
WESTERN CHIPPEWA/MACKINAC BACK INTO THE ACTION DURING THE DAY AS
WELL.
SNOWFALL: MOBILE SNOWBAND WILL KEEP A LID ON SNOW AMOUNTS...BUT
COULD SEE 1-3" FOR THE DAY TODAY OVER THE NW SNOWBELTS...WITH MOST
OF THIS FALLING BEFORE ACTIVITY BECOMES MORE CELLULAR THIS
AFTERNOON.
WHILE WE LOSE HELP FROM ANY ISALLOBARIC COMPONENT TO THE LLEVEL
WINDS TODAY...H9 WINDS 25-30KTS AND AMPLE LLEVEL MIXING SUGGEST
WINDS 15-25 MPH WINDS WITH GUSTS WELL INTO THE 30S...PARTICULARLY
NEAR THE LAKESHORES AND OVER EASTERN UPPER.
TEMPS WILL BE VERY SLOW TO CLIMB WITH T9 AROUND -10C SUGGESTING MID
20S /SOME 20F BELOW NORMAL/ WILL BE ABOUT ALL WE CAN MUSTER. WITH
THE STRONG WINDS...WIND CHILLS WILL REMAIN IN THE TEENS THROUGH THE
DAY.
HEADLINES: WILL GO AHEAD AND DROP WINTER WEATHER ADVISORY FOR
CHIPPEWA GIVEN LOCATION OF SNOWFALL ACTIVITY WELL WEST OF COUNTY
WITH ACCUMS THUS FAR NOT SUFFICIENT TO WARRANT THE HEADLINE.
AS DISCUSSED ABOVE...HEAVIEST SNOW IS NOW OVER THE BIG 5 IN NW
LOWER...AND WILL MONITOR FOR POTENTIAL HEADLINE THROUGH
DAYBREAK...ALTHOUGH EXPECTATION IS THAT THE BAND WILL BEGIN TO
MOVE...REDUCING THE THREAT OF SIGNIFICANT ACCUMS.
TONIGHT: SYNOPTIC MOISTURE BEGINS TO SLOWLY ERODE WITH TEMPS ALOFT
STEADY OR JUST SLIGHTLY WARING UNDER A FAIRLY STEADY 300-310 FLOW
REGIME. SOME RESIDUAL LAND-BASED CAPE CONTINUES THROUGH THE
OVERNIGHT WHICH MAY NOT FULLY ALLOW THE LAKE EFFECT TO RE-SOLIDIFY
INTO BANDS. SHSN WILL CERTAINLY CONTINUE...HOWEVER...WITH
ADDITIONAL LIGHT ACCUMULATIONS LIKELY. INHERITED ACCUMS OF 1-2
INCHES /PERHAPS 3 OVER WESTERN CHIPPEWA/ LOOK REASONABLE AND HAVE NO
COMPELLING REASON TO DEVIATE SIGNIFICANTLY.
CLOUDS WILL LIKELY KEEP TEMPERATURES FROM FALLING ALL THAT FAR...
GENERALLY IN THE UPPER TEENS TO AROUND 20.
&&
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 422 AM EDT MON APR 1 2013
TUESDAY...AS THE SFC HIGH BEGINS TO MOVE INTO THE REGION, THE 850 MB
TEMPERATURES BEGIN TO WARM SLIGHTLY, JUST ENOUGH THAT WE MAY LOSE
THE INSTABILITY NEEDED FOR THE LES. THE MOISTURE IN THE 850-700 MB
LAYER FALLS OFF TO BELOW 60% ON ALL THE MODELS SO WOULD EXPECT LIGHT
SNOW AND FLURRIES. ALTHOUGH WILL HAVE LIKELY POPS SINCE MEASURABLE
SNOW IS EXPECTED FROM THIS PATTERN IN THE MORNING. BY THE AFTERNOON,
THE MOISTURE CONTINUES TO FALL OFF IN THE 850-700 MB LAYER. THE ONE
THING THAT I HAVE NOTICED ABOUT THESE LATE SEASON LES EVENTS IS THAT
IT HAS BECOME HARD FOR THE LOWER END OF THE SOUNDINGS TO SATURATE.
THIS HAS BEEN LEADING TO INVERTED V SOUNDINGS AND REALIZING LESS
SNOW THAN WE WOULD HAVE EVEN A MONTH AGO DURING THE AFTERNOON.
TUESDAY NIGHT...AS THE RIDGE BUILDS INTO THE REGION, THE DRIER AIR
REALLY BEGINS TO OVERWHELM THE REGION, SHUTTING OFF MOST OF THE SNOW
LEAVING ONLY CHANCE POPS IN THE EVENING IN E UPPER, WHILE N LOWER
WILL BE DRY ENOUGH TO NOT HAVE ANY SNOW.
WEDNESDAY...HIGH PRESSURE AT THE SFC AND 500 MB RIDGE MOVES THROUGH
THE REGION SO THAT WE WILL REMAIN DRY FOR THE DAY. OVERNIGHT, A COLD
FRONT AND 500 MB SHORTWAVE TROUGH MOVE INTO THE REGION. THE GFS IS A
LITTLE FASTER THAN THE ECMWF AND NAM. WILL HOLD OFF THE SNOW BY
ALLOWING IT TO JUST TOUCH E UPPER BY 12Z.
EXTENDED (THURSDAY THROUGH SUNDAY)...THURSDAY, THE MODELS DRY THINGS
OUT WITH THE FRONTAL PASSAGE DURING THE DAY. SO WILL HAVE CHANCE
POPS WITH A MIX OF THE RAIN AND SNOW IN E UPPER AND JUST RAIN IN N
LOWER. WITH THE SFC TEMPERATURES IN THE 40S, WOULD NOT BE SURPRISED
IF THIS TURNS OUT TO BE FLURRIES AND SPRINKLES. FRIDAY, THE HIGH
BUILDS INTO THE UPPER GREAT LAKES REGION AND DRIES THINGS OUT AGAIN.
SO DRY WEATHER WILL BE EXPECTED. SATURDAY, THE WARM FRONT WILL BE
MOVING INTO THE REGION. THE ECMWF HAS THE WARM AIR INTO E UPPER SO
THAT IT COULD BE ALL RAIN, WHILE THE GFS HAS IT PLACED A LITTLE
SOUTH. PUT THE DIVIDING LINE AT THE STRAITS SINCE THAT SEEMED TO BE
THE MIDDLE GROUND. WHICH WOULD CONTINUE THROUGH THE NIGHT AS THE
SYSTEM MOVES EAST. SUNDAY, THE LOW MOVES EAST OF THE REGION AND THE
COLD AIR MOVES BACK IN ALLOWING FOR A CHANGE OVER TO SNOW. THE GFS
DRIES THINGS OUT. WILL LEAN TOWARD THE ECMWF WHICH WOULD BE THE
PESSIMISTIC FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 128 AM EDT MON APR 1 2013
SUMMARY: STRONG NORTHWEST FLOW WILL CONTINUE THROUGH THE UPCOMING
TAF PERIOD...WITH LAKE EFFECT SNOW SHOWERS OCCASIONALLY IMPACTING
THE TERMINALS.
RESTRICTIONS: EXPECT VFR CONDITIONS TO DOMINATE MOST OF THE TAF
PERIOD...WITH HEAVIEST LES OVERNIGHT TONIGHT REMAINING BETWEEN PLN
AND TVC. BANDING LOOKS TO TARGET PLN SOMETIME LATER THIS
MORNING/EARLY AFTERNOON...ALTHOUGH IT WILL LIKELY BE BREAKING UP
INTO MORE CELLULAR ACTIVITY BY THIS TIME. SO...WILL ONLY INCLUDE
A PERIOD OF MVFR WITH THIS TAF PACKAGE...AND AWAIT LATER TRENDS TO
POTENTIALLY ADD A SHORT PERIOD OF IFR.
AT THE OTHER TERMINALS...WHILE A QUICK DROP TO MVFR IN SHSN IS
POSSIBLE...THERE IS LOW CONFIDENCE IN TIMING...SO WILL FOLLOW TRENDS
THROUGH THE REMAINDER OF THE OVERNIGHT BEFORE ADDING ANY TEMPOS AT
TVC/APN. AT THIS TIME...MBL LOOKS TO REMAIN VFR.
WINDS: NORTHWEST WINDS 14G22KTS TONIGHT WILL CONTINUE 18G28KTS FOR
THE DAY ON MONDAY BEFORE DIMINISHING TO 10-15KTS MONDAY NIGHT.
&&
.MARINE...
ISSUED AT 422 AM EDT MON APR 1 2013
SUMMARY: STRONG NORTHWESTERLY WINDS TO CONTINUE THROUGH TUESDAY AS
LOW PRESSURE MOVES INTO EASTERN CANADA. HIGH PRESSURE ARRIVES BY
MIDWEEK WITH QUIETER CONDITIONS EXPECTED.
HEADLINES: MARGINAL GALES WILL BE ALLOWED TO CONTINUE ALL ZONES
THROUGH THIS EVENING. SMALL CRAFTS WILL CERTAINLY BE NEEDED BEYOND
THIS...WITH ADDITIONAL GALE FORCE GUSTS POSSIBLE AGAIN
TUESDAY...PARTICULARLY FOR NORTHWESTERLY FLOW FAVORED REGIONS.
BEYOND THIS...NEXT ROUND OF SMALL CRAFTS LOOKS LIKELY BY WEDNESDAY
NIGHT OVER LAKE MICHIGAN AS SOUTHWESTERLY WINDS STRENGTHEN AHEAD OF
NEXT APPROACHING SYSTEM.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LHZ345>349.
LM...GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LMZ323-341-342-
344>346.
LS...GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LSZ321-322.
&&
$$
SYNOPSIS...JL
SHORT TERM...ARNOTT
LONG TERM...JL
AVIATION...ARNOTT
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
235 AM EDT MON APR 1 2013
.UPDATE...
ISSUED AT 233 AM EDT MON APR 1 2013
OPTED TO UPGRADE ADVY FOR ALGER/NRN SCHOOLCRAFT TO A WARNING GIVEN
PERSISTENCE OF INTENSE LES BAND JUST E OF MUNISING UNDER COLDER CLD
TOPS ASSOCIATED WITH DEEPENING UPR TROF...FVRBL SN/WATER RATIOS WITH
UVV MAX WITHIN DGZ...AND REPORTS OF SGNFT BLSN/WHITEOUT CONDITIONS
ALONG M-28. ALTHOUGH THE EXPECTED DEPARTURE OF THE COLDER CLD TOPS
BY 09Z WOULD SUG THE BAND WL DIMINISH...PERSISTENCE OF BAND SINCE
MID EVNG ARND 03Z AND ESTIMATED SN ACCUMS UP TO 2 INCHES/HR SINCE
BAND DVLPD SUG WARNING AMNTS ARE LIKELY FM SHINGLETON AND MELSTRAND
TO GRAND MARAIS AND SENEY.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 451 PM EDT SUN MAR 31 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF DEEPENING INTO THE
GREAT LAKES REGION. VIGOROUS SHORTWAVE WAS PASSING OVER LAKE
SUPERIOR. PER SATELLITE IMAGERY AND CANADIAN RADAR IMAGERY...AN
ASSOCIATED IMPRESSIVE LOOKING SMALL SWATH OF MDT TO HVY SNOW HAS
PASSED JUST N OF THE FCST AREA ACROSS FAR NRN LAKE SUPERIOR/ADJACENT
ONTARIO TODAY...ALONG/JUST N OF SHORTWAVE TRACK. AN INCREASINGLY
WELL-DEFINED SFC LOW PRES IS ORGANIZING OVER EASTERN LAKE ATTM PER
VIS SATELLITE IMAGERY. TO THE S...-SHSN TODAY HAVE DEFINITELY TAKEN
ON A SPRINGTIME DIURNAL LAND BASED LOOK WITH UNORGANIZED SCT/NMRS
COVERAGE. WELL-MIXED LAYER HAS PREVENTED SOME OF THE PCPN FROM
REACHING THE GROUND. UPSTREAM 12Z KINL SOUNDING SHOWED A DEEP
MOISTURE PROFILE TO 650MB (AROUND 11KFT)... AND MODIFYING SOUNDING
FOR A SFC T/TD IN THE LWR 30S/LWR 20S YIELDED SBCAPE AROUND
100J/KG...AND THUS THE DIURNAL COMPONENT TO THE -SHSN THIS AFTN.
MAIN FCST ISSUES TONIGHT/MON ARE POTENTIAL LES ACCUMULATIONS AS WELL
AS WINDS. FIRST UP...WINDS. EXPECT STRONGEST WINDS TO OCCUR FROM NOW
THRU THE ABOUT MID EVENING AS AREA OF 4MB/3HR PRES RISES CURRENTLY
JUST NW OF LAKE SUPERIOR SETTLES SE. THE DEEPENING INCREASINGLY
WELL-DEFINED SFC LOW OVER ERN LAKE SUPERIOR IS A CONCERN AS IT WILL
SERVE TO STRENGTHEN ISALLOBARIC WINDS. SOME OF THE HIGHER RES MODEL
GUIDANCE SEEMS TO BE PICKING UP ON THIS AS A SMALL 5-6MB/3HR PRES
RISE MAX DEVELOPS OVER CNTRL/ERN LAKE SUPERIOR WITHIN THE LARGER
SCALE PRES RISES. THE IMPACT OF THE DEEPENING LOW HAS ALREADY MADE
AN IMPACT AS WINDS HAVE GUSTED TO 50MPH AT KP59. THIS SHOULD BE A
GOOD INDICATION OF WHAT IS TO COME IN THE NEXT FEW HRS TO THE E OF
MARQUETTE. WIND ADVY HAS BEEN ISSUED FOR KEWEENAW COUNTY INTO MID
EVENING TO ACCOUNT FOR STRONG WINDS OVER THE NEXT FEW HRS.
AS FOR SNOW...NNW CYCLONIC FLOW SHOULD ALLOW SOME OF THE DEEPER
MOISTURE IN NRN ONTARIO PER 12Z CWPL SOUNDING WHICH SHOWED DEEP
MOISTURE TO 425MB (20500FT) TO SLIP INTO THE UPPER LAKES. WITH 850MB
TEMPS FALLING TO -18C BY 12Z MON...A 3KFT THICK DGZ LAYER FALLS
NICELY INTO THE CONVECTIVE LAYER WHERE NAM INDICATES RATHER VIGOROUS
UPWARD MOTION TONIGHT. WITH EQUILIBRIUM LEVELS LIKELY ABOVE 10KFT...
LES SHOULD GET GOING AT A PRETTY GOOD CLIP...BUT THE LES WILL
LIKELY TAKE SOME TIME TO GET FULLY DEVELOPED AND ORGANIZED AS THE
TYPICAL DISRUPTIVE EFFECTS OF SPRING DAYTIME HEATING ON LES WILL
NEED TO BE ERODED AWAY FIRST. ALTHOUGH IT`S NOT ESPECIALLY COLD
YET...NOTE THAT THE LAKE IS HAVING MORE OF A STABILIZING INFLUENCE
WITH LESS CLOUD OVER THE WATER THAN LAND...EXCEPT RIGHT IN THE VCNTY
OF THE SFC LOW. THE OVERNIGHT PERIOD THRU MON MORNING SHOULD BE THE
PRIME PERIOD OF LES...AND THE GOING ADVY LOOKS ON TRACK FOR THE ERN
COUNTIES ALONG LAKE SUPERIOR. WILL PROBABLY SEE SOME ACCUMULATIONS
UP TO 6-7 INCHES BY MON AFTN. CONSIDERABLE BLSN WILL ALSO BE AN
ISSUE...ESPECIALLY IN OPEN AREAS NEAR LAKE SUPERIOR. THE W WILL BE
MORE ON THE FRINGE OF THE DEEPER MOISTURE PLUS FCST SOUNDINGS SHOW
MORE OF A WELL MIXED BOUNDARY LAYER LINGERING THRU THE NIGHT WHICH
ARGUES FOR LIGHTER LES THAN OVER THE E. ACCUMULATIONS TONIGHT THRU
EARLY MON AFTN SHOULD BE IN THE 1-4 INCH RANGE OVER THE W...
INCLUDING INTO THE HIGHER TERRAIN OF NW MARQUETTE COUNTY.
CONDITIONS REMAIN FAVORABLE FOR LES MON AS 850MB TEMPS ONLY RISE A
DEGREE OR TWO IN THE AFTN. MOISTURE PROFILE REMAINS DEEP OVER THE
E...BUT DOES BECOME MORE SHALLOW OVER THE W. SO LES WILL DIMINISH
OVER THE W. EVEN OVER THE E...EXPECT LES TO BEGIN TO DIMINISH IN THE
AFTN AS STRONG DAYTIME HEATING DISRUPTS LES PROCESSES.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 451 PM EDT SUN MAR 31 2013
LAKE EFFECT WILL BE ONGOING AT THE START OF THE LONGER TERM PERIOD
ON MONDAY NIGHT. INVERSIONS 6-8KFT AND DELTA T/S AROUND 18C WITH
LAKE EQL NEARING 10KFT INDICATE NW FLOW AREAS EAST OF MARQUETTE WILL
CONTINUE TO SEE LIGHT AND MAYBE MODERATE SNOW ACCUMS AND CONTINUING
BLOWING SNOW. HEAVIER SNOW LIKELY OCCURS OVERNIGHT MONDAY NIGHT
THROUGH EARLY TUESDAY MORNING WHEN DIURNAL DISRUPTION IS MINIMAL
AND WHEN LOW-LEVEL CONVERGENCE IS STRONGEST. POSSIBLE THAT MORE
ADVISORIES MAY BE NEEDED MONDAY NIGHT THROUGH TUESDAY MORNING IN
AREAS THAT ARE CURRENTLY IN A HEADLINE.
SFC-H85 FLOW BECOMES INCREASINGLY ANTICYCLONIC TUESDAY WHICH OFFSETS
SUFFICIENT OVER-WATER INSTABILITY AS H85 TEMPS STAY AOB -15C THROUGH
18Z TUESDAY. GFS SOUNDINGS SHOW INVERSION FALLING BLO 5KFT OVR WEST
AFT 12Z AND TO AROUND 5KFT FOR AREAS OVR EASTERN CWA. NO ADDITIONAL
DEEPER MOISTURE AND CYCLONIC FLOW AT A MINIMUM SHOULD COMBINE WITH
HIGHER EARLY APRIL SUN ANGLE/BLYR HEATING TO CONSIDERABLY DISRUPT
LAKE EFFECT BY TUESDAY AFTN. GFS/GEM-NH SLIGHTLY LOWER WITH HEIGHTS
AND COLDER AT H85 FARTHER WEST TUESDAY NIGHT INTO EARLY WEDNESDAY
MORNING. RESULT IS AT LEAST ISOLD LK EFFECT CONTINUING OVER FAR
EASTERN CWA. ECMWF MORE PROGRESSIVE WITH HEIGHTS AND KEEPS COLDER
AIR ON THE MOVE LEADING TO LESS OF CHANCE OF LK EFFECT INTO
WEDNESDAY. SOME HINT OF ANOTHER WEAKER TROUGH UPSTREAM THAT WILL
HAVE TO DROP ACROSS THE UPPER LAKES AS LARGER TROUGH MOVES TO EAST.
WILL HEDGE FORECAST TOWARD GFS/GEM-NH IDEA.
SHORTWAVE RIDGING SLIDES ACROSS AREA FOR WEDNESDAY. LINGERING LK
EFFECT CLOUDS/FLURRIES IN THE MORNING EAST...BUT THIS SHOULD BREAK
UP IN AFTN WITH ARRIVAL OF SFC-H925 RIDGE. MAY SEE INCREASING HIGH
CLOUDS OVER WEST BY LATE AFTN. OTHERWISE...A WARMER DAY SHAPING UP
WITH LIGHT WINDS/LAKE BREEZES. MIXING TO H9-H85 SUPPORTS MAX TEMPS
AS WARM AS LOWER 40S IN THE WEST AND STILL ABOVE THE FREEZING MARK
ELSEWHERE.
HIGH CLOUDS SPILLING IN LATE ON WEDNESDAY ARE IN ADVANCE OF
SHORTWAVE TROUGH TRACKING ACROSS NORTHERN MANITOBA AND NORTHERN
ONTARIO. MODELS STILL AT ODDS HOW QUICKLY THIS SYSTEM MOVES
THROUGH WEDNESDAY NIGHT AND THURSDAY. 00Z GFS WAS SLOWER BUT 06Z
LOOKS MORE LIKE ECMWF. GEM-NH WRAPPED UP AND SLOWER. HEIGHT FALLS
AND H7-H5 Q-VECTOR CONVERGENCE FOCUS MOST PRECIPITATION WELL TO
NORTH OF LK SUPERIOR. SFC-H85 FRONT/1000-850MB MOISTURE CONVERGENCE
SWINGING ACROSS LK SUPERIOR AND UPR MICHIGAN...ALONG WITH RIBBON OF
HIGHER H85-H7 MOISTURE...H85 MOISTURE/TEMPERATURE ADVECTION AND
STEEPER H7-H5 LAPSE RATES AOA 6.5C/KM NOSING IN FROM WEST ADD UP TO
BRIEF PERIOD OF SCATTERED PRECIPITATION AS FRONT WORKS THROUGH. IF
TIMING IS LIKE ECMWF...THEN BETTER CHANCES WILL BE IN THE NORTH. IF
TIMING ENDS UP SLOWER...THEN MORE AREAS SEE CHANCES AS HEATING
OF THE DAY COMBINES WITH THE FORCING. EVEN WITH SLOWER IDEA...MOST
PRECIP SHOULD BE OUT OF AREA BY MID AFTN. PTYPE ALSO DEPENDS ON
TIMING AS A LATER ARRIVAL WOULD BRING RAIN POTENTIAL INTO MIX.
FOR NOW...LOOKS LIKE MOSTLY SNOW AS SOUNDINGS INDICATE WET BULB
FALLS BLO ZERO EXCEPT FOR FAR LOWEST REACHES OF BLYR. ONCE FRONT
MOVES THROUGH QUIET WEATHER EXPECTED THROUGH FRIDAY AS HIGH PRESSURE
DRIFTS ACROSS. GFS A FEW DEGREES COLDER AT H85 ON FRIDAY COMPARED TO
ECMWF AND THUS HAS MORE IN WAY OF LAKE EFFECT CLOUDS.
SYSTEM FOR NEXT WEEKEND STILL SHOWING UP...BUT THERE REMAIN SOME
BIG QUESTIONS. UPPER LAKES REMAINS ON SOUTHERN EDGE OF STRONGER JET
STREAM RIDING ALONG SOUTHERN TIER OF CANADA...WHICH WILL HELP
ENHANCE PRECIPITATION ALONG SFC-H85 BAROCLINIC ZONE. WHERE THAT ZONE
IS LOCATED IS UNCERTAIN. AS MID-LEVEL FLOW BECOMES MORE WESTERLY...
SHORTWAVE TROUGH AND SFC-H85 LOWS MOVE FROM ROCKIES ACROSS THE
NORTHERN PLAINS INTO WESTERN GREAT LAKES. OPERATIONAL MODELS FROM
LAST NIGHT AND NAEFS ENSEMBLES INDICATED SLOWER ARRIVAL TO
PRECIPITATION NOT IMPACTING MUCH OF UPR MICHIGAN UNTIL SATURDAY
NIGHT. OF COURSE THE 12Z MODELS HAVE TRENDED QUICKER AGAIN. ECMWF IS
A LOT QUICKER...BRINGING QPF OVER MOST OF UPR MICHIGAN BY 12Z
SATURDAY...AND BASED ON 1000-500MB THICKNESS/H85 TEMPS IS SHOWING
BETTER SHOT AT MIXED PRECIPITATION. KIND OF SEEMS LIKE ECMWF IS
SHOWING TWO SEPARATE WAVES OF QPF AND THAT IS WHY IT APPEARS MUCH
FASTER WITH QPF ARRIVAL. POOR RUN-TO-RUN CONSISTENCY CONTINUES WITH
THE SYSTEM. UNTIL CONSISTENCY IMPROVES WILL KEEP WITH CONSENSUS OF
MODELS FOR THIS SYSTEM FOR POPS. ENOUGH OF A SIGNAL FROM MODELS OVER
LAST COUPLE DAYS TO GO WITH RAIN AND SNOW FOR PTYPE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 129 AM EDT MON APR 1 2013
INCREASINGLY COLDER AIR MOVING ACROSS LAKE SUPERIOR IN NW FLOW WILL
SUSTAIN PERIODS OF LAKE EFFECT SNOW SHOWERS AND MVFR CONDITIONS INTO
MONDAY AT ALL 3 TAF SITES. GUSTY NW WINDS TO 25 KTS AT TIMES COULD
ALSO CONTRIBUTE TO LOWER IFR VSBYS IN SNOW AND BLOWING SNOW...MAINLY
AT MORE EXPOSED KCMX SITE. WINDS BACKING A BIT MORE TO THE
WNW...SHOULD REDUCE CHCS FOR LAKE EFFECT SNOW SHOWERS AT KSAW BY
MONDAY AFTERNOON...PERHAPS EVEN LEADING TO VFR CONDITIONS BY MONDAY
EVENING. ARRIVAL OF DRIER NEAR SFC AIR SHOWN ON THE 00Z INL RAOB WILL
ALSO BRING ABOUT LONG PERIODS OF VFR CONDITIONS AT IWD. THE
COMBINATION OF THE DRYING AND DAYTIME HEATING THIS AFTN WILL DIMINISH
THE LES INTENSITY AT CMX AS WELL.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 451 PM EDT SUN MAR 31 2013
STRONG NORTH TO NORTHWEST GALES TO 45 KTS INTO EARLY THIS EVENING
AS COLD FRONT CROSSES LK SUPERIOR. STRONGEST WINDS OCCUR THROUGH
LATE EVENING IN CORRIDOR FROM CNTRL LK SUPERIOR BUOY TO STANNARD
ROCK AND ACROSS REST OF EASTERN LK SUPERIOR. GALES CONTINUE THROUGH
MONDAY AND MONDAY NIGHT OVER SAME AREAS...BUT NOT QUITE AS STRONG.
WINDS DIMINISH TO LESS THAN 25 KTS BY WEDNESDAY MORNING AS BRIEF
RIDGING MOVES ACROSS. STRONGER SOUTHWEST WINDS TO 30 KTS THEN
EXPECTED WEDNESDAY NIGHT AND THURSDAY MORNING AS LOW PRESSURE
CROSSES NORTHERN ONTARIO AND DRAGS COLD FRONT ACROSS LK SUPERIOR.
NORTHWEST WINDS TO 25 KTS DEVELOP BEHIND THE FRONT INTO NEXT
WEEKEND. THE STRONG WINDS WILL DRAW MUCH COLDER AIR INTO THE UPPER
LAKES EARLY THIS WEEK RESULTING IN FREEZING SPRAY THROUGH TUESDAY
NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR MIZ007.
LAKE EFFECT SNOW WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR
MIZ006-085.
LAKE SUPERIOR...
GALE WARNING UNTIL 6 AM EDT TUESDAY FOR LSZ250-251-266-267.
GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR LSZ244-245-264-265.
GALE WARNING UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ249.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...VOSS/KC
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
138 AM EDT MON APR 1 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 451 PM EDT SUN MAR 31 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF DEEPENING INTO THE
GREAT LAKES REGION. VIGOROUS SHORTWAVE WAS PASSING OVER LAKE
SUPERIOR. PER SATELLITE IMAGERY AND CANADIAN RADAR IMAGERY...AN
ASSOCIATED IMPRESSIVE LOOKING SMALL SWATH OF MDT TO HVY SNOW HAS
PASSED JUST N OF THE FCST AREA ACROSS FAR NRN LAKE SUPERIOR/ADJACENT
ONTARIO TODAY...ALONG/JUST N OF SHORTWAVE TRACK. AN INCREASINGLY
WELL-DEFINED SFC LOW PRES IS ORGANIZING OVER EASTERN LAKE ATTM PER
VIS SATELLITE IMAGERY. TO THE S...-SHSN TODAY HAVE DEFINITELY TAKEN
ON A SPRINGTIME DIURNAL LAND BASED LOOK WITH UNORGANIZED SCT/NMRS
COVERAGE. WELL-MIXED LAYER HAS PREVENTED SOME OF THE PCPN FROM
REACHING THE GROUND. UPSTREAM 12Z KINL SOUNDING SHOWED A DEEP
MOISTURE PROFILE TO 650MB (AROUND 11KFT)... AND MODIFYING SOUNDING
FOR A SFC T/TD IN THE LWR 30S/LWR 20S YIELDED SBCAPE AROUND
100J/KG...AND THUS THE DIURNAL COMPONENT TO THE -SHSN THIS AFTN.
MAIN FCST ISSUES TONIGHT/MON ARE POTENTIAL LES ACCUMULATIONS AS WELL
AS WINDS. FIRST UP...WINDS. EXPECT STRONGEST WINDS TO OCCUR FROM NOW
THRU THE ABOUT MID EVENING AS AREA OF 4MB/3HR PRES RISES CURRENTLY
JUST NW OF LAKE SUPERIOR SETTLES SE. THE DEEPENING INCREASINGLY
WELL-DEFINED SFC LOW OVER ERN LAKE SUPERIOR IS A CONCERN AS IT WILL
SERVE TO STRENGTHEN ISALLOBARIC WINDS. SOME OF THE HIGHER RES MODEL
GUIDANCE SEEMS TO BE PICKING UP ON THIS AS A SMALL 5-6MB/3HR PRES
RISE MAX DEVELOPS OVER CNTRL/ERN LAKE SUPERIOR WITHIN THE LARGER
SCALE PRES RISES. THE IMPACT OF THE DEEPENING LOW HAS ALREADY MADE
AN IMPACT AS WINDS HAVE GUSTED TO 50MPH AT KP59. THIS SHOULD BE A
GOOD INDICATION OF WHAT IS TO COME IN THE NEXT FEW HRS TO THE E OF
MARQUETTE. WIND ADVY HAS BEEN ISSUED FOR KEWEENAW COUNTY INTO MID
EVENING TO ACCOUNT FOR STRONG WINDS OVER THE NEXT FEW HRS.
AS FOR SNOW...NNW CYCLONIC FLOW SHOULD ALLOW SOME OF THE DEEPER
MOISTURE IN NRN ONTARIO PER 12Z CWPL SOUNDING WHICH SHOWED DEEP
MOISTURE TO 425MB (20500FT) TO SLIP INTO THE UPPER LAKES. WITH 850MB
TEMPS FALLING TO -18C BY 12Z MON...A 3KFT THICK DGZ LAYER FALLS
NICELY INTO THE CONVECTIVE LAYER WHERE NAM INDICATES RATHER VIGOROUS
UPWARD MOTION TONIGHT. WITH EQUILIBRIUM LEVELS LIKELY ABOVE 10KFT...
LES SHOULD GET GOING AT A PRETTY GOOD CLIP...BUT THE LES WILL
LIKELY TAKE SOME TIME TO GET FULLY DEVELOPED AND ORGANIZED AS THE
TYPICAL DISRUPTIVE EFFECTS OF SPRING DAYTIME HEATING ON LES WILL
NEED TO BE ERODED AWAY FIRST. ALTHOUGH IT`S NOT ESPECIALLY COLD
YET...NOTE THAT THE LAKE IS HAVING MORE OF A STABILIZING INFLUENCE
WITH LESS CLOUD OVER THE WATER THAN LAND...EXCEPT RIGHT IN THE VCNTY
OF THE SFC LOW. THE OVERNIGHT PERIOD THRU MON MORNING SHOULD BE THE
PRIME PERIOD OF LES...AND THE GOING ADVY LOOKS ON TRACK FOR THE ERN
COUNTIES ALONG LAKE SUPERIOR. WILL PROBABLY SEE SOME ACCUMULATIONS
UP TO 6-7 INCHES BY MON AFTN. CONSIDERABLE BLSN WILL ALSO BE AN
ISSUE...ESPECIALLY IN OPEN AREAS NEAR LAKE SUPERIOR. THE W WILL BE
MORE ON THE FRINGE OF THE DEEPER MOISTURE PLUS FCST SOUNDINGS SHOW
MORE OF A WELL MIXED BOUNDARY LAYER LINGERING THRU THE NIGHT WHICH
ARGUES FOR LIGHTER LES THAN OVER THE E. ACCUMULATIONS TONIGHT THRU
EARLY MON AFTN SHOULD BE IN THE 1-4 INCH RANGE OVER THE W...
INCLUDING INTO THE HIGHER TERRAIN OF NW MARQUETTE COUNTY.
CONDITIONS REMAIN FAVORABLE FOR LES MON AS 850MB TEMPS ONLY RISE A
DEGREE OR TWO IN THE AFTN. MOISTURE PROFILE REMAINS DEEP OVER THE
E...BUT DOES BECOME MORE SHALLOW OVER THE W. SO LES WILL DIMINISH
OVER THE W. EVEN OVER THE E...EXPECT LES TO BEGIN TO DIMINISH IN THE
AFTN AS STRONG DAYTIME HEATING DISRUPTS LES PROCESSES.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 451 PM EDT SUN MAR 31 2013
LAKE EFFECT WILL BE ONGOING AT THE START OF THE LONGER TERM PERIOD
ON MONDAY NIGHT. INVERSIONS 6-8KFT AND DELTA T/S AROUND 18C WITH
LAKE EQL NEARING 10KFT INDICATE NW FLOW AREAS EAST OF MARQUETTE WILL
CONTINUE TO SEE LIGHT AND MAYBE MODERATE SNOW ACCUMS AND CONTINUING
BLOWING SNOW. HEAVIER SNOW LIKELY OCCURS OVERNIGHT MONDAY NIGHT
THROUGH EARLY TUESDAY MORNING WHEN DIURNAL DISRUPTION IS MINIMAL
AND WHEN LOW-LEVEL CONVERGENCE IS STRONGEST. POSSIBLE THAT MORE
ADVISORIES MAY BE NEEDED MONDAY NIGHT THROUGH TUESDAY MORNING IN
AREAS THAT ARE CURRENTLY IN A HEADLINE.
SFC-H85 FLOW BECOMES INCREASINGLY ANTICYCLONIC TUESDAY WHICH OFFSETS
SUFFICIENT OVER-WATER INSTABILITY AS H85 TEMPS STAY AOB -15C THROUGH
18Z TUESDAY. GFS SOUNDINGS SHOW INVERSION FALLING BLO 5KFT OVR WEST
AFT 12Z AND TO AROUND 5KFT FOR AREAS OVR EASTERN CWA. NO ADDITIONAL
DEEPER MOISTURE AND CYCLONIC FLOW AT A MINIMUM SHOULD COMBINE WITH
HIGHER EARLY APRIL SUN ANGLE/BLYR HEATING TO CONSIDERABLY DISRUPT
LAKE EFFECT BY TUESDAY AFTN. GFS/GEM-NH SLIGHTLY LOWER WITH HEIGHTS
AND COLDER AT H85 FARTHER WEST TUESDAY NIGHT INTO EARLY WEDNESDAY
MORNING. RESULT IS AT LEAST ISOLD LK EFFECT CONTINUING OVER FAR
EASTERN CWA. ECMWF MORE PROGRESSIVE WITH HEIGHTS AND KEEPS COLDER
AIR ON THE MOVE LEADING TO LESS OF CHANCE OF LK EFFECT INTO
WEDNESDAY. SOME HINT OF ANOTHER WEAKER TROUGH UPSTREAM THAT WILL
HAVE TO DROP ACROSS THE UPPER LAKES AS LARGER TROUGH MOVES TO EAST.
WILL HEDGE FORECAST TOWARD GFS/GEM-NH IDEA.
SHORTWAVE RIDGING SLIDES ACROSS AREA FOR WEDNESDAY. LINGERING LK
EFFECT CLOUDS/FLURRIES IN THE MORNING EAST...BUT THIS SHOULD BREAK
UP IN AFTN WITH ARRIVAL OF SFC-H925 RIDGE. MAY SEE INCREASING HIGH
CLOUDS OVER WEST BY LATE AFTN. OTHERWISE...A WARMER DAY SHAPING UP
WITH LIGHT WINDS/LAKE BREEZES. MIXING TO H9-H85 SUPPORTS MAX TEMPS
AS WARM AS LOWER 40S IN THE WEST AND STILL ABOVE THE FREEZING MARK
ELSEWHERE.
HIGH CLOUDS SPILLING IN LATE ON WEDNESDAY ARE IN ADVANCE OF
SHORTWAVE TROUGH TRACKING ACROSS NORTHERN MANITOBA AND NORTHERN
ONTARIO. MODELS STILL AT ODDS HOW QUICKLY THIS SYSTEM MOVES
THROUGH WEDNESDAY NIGHT AND THURSDAY. 00Z GFS WAS SLOWER BUT 06Z
LOOKS MORE LIKE ECMWF. GEM-NH WRAPPED UP AND SLOWER. HEIGHT FALLS
AND H7-H5 Q-VECTOR CONVERGENCE FOCUS MOST PRECIPITATION WELL TO
NORTH OF LK SUPERIOR. SFC-H85 FRONT/1000-850MB MOISTURE CONVERGENCE
SWINGING ACROSS LK SUPERIOR AND UPR MICHIGAN...ALONG WITH RIBBON OF
HIGHER H85-H7 MOISTURE...H85 MOISTURE/TEMPERATURE ADVECTION AND
STEEPER H7-H5 LAPSE RATES AOA 6.5C/KM NOSING IN FROM WEST ADD UP TO
BRIEF PERIOD OF SCATTERED PRECIPITATION AS FRONT WORKS THROUGH. IF
TIMING IS LIKE ECMWF...THEN BETTER CHANCES WILL BE IN THE NORTH. IF
TIMING ENDS UP SLOWER...THEN MORE AREAS SEE CHANCES AS HEATING
OF THE DAY COMBINES WITH THE FORCING. EVEN WITH SLOWER IDEA...MOST
PRECIP SHOULD BE OUT OF AREA BY MID AFTN. PTYPE ALSO DEPENDS ON
TIMING AS A LATER ARRIVAL WOULD BRING RAIN POTENTIAL INTO MIX.
FOR NOW...LOOKS LIKE MOSTLY SNOW AS SOUNDINGS INDICATE WET BULB
FALLS BLO ZERO EXCEPT FOR FAR LOWEST REACHES OF BLYR. ONCE FRONT
MOVES THROUGH QUIET WEATHER EXPECTED THROUGH FRIDAY AS HIGH PRESSURE
DRIFTS ACROSS. GFS A FEW DEGREES COLDER AT H85 ON FRIDAY COMPARED TO
ECMWF AND THUS HAS MORE IN WAY OF LAKE EFFECT CLOUDS.
SYSTEM FOR NEXT WEEKEND STILL SHOWING UP...BUT THERE REMAIN SOME
BIG QUESTIONS. UPPER LAKES REMAINS ON SOUTHERN EDGE OF STRONGER JET
STREAM RIDING ALONG SOUTHERN TIER OF CANADA...WHICH WILL HELP
ENHANCE PRECIPITATION ALONG SFC-H85 BAROCLINIC ZONE. WHERE THAT ZONE
IS LOCATED IS UNCERTAIN. AS MID-LEVEL FLOW BECOMES MORE WESTERLY...
SHORTWAVE TROUGH AND SFC-H85 LOWS MOVE FROM ROCKIES ACROSS THE
NORTHERN PLAINS INTO WESTERN GREAT LAKES. OPERATIONAL MODELS FROM
LAST NIGHT AND NAEFS ENSEMBLES INDICATED SLOWER ARRIVAL TO
PRECIPITATION NOT IMPACTING MUCH OF UPR MICHIGAN UNTIL SATURDAY
NIGHT. OF COURSE THE 12Z MODELS HAVE TRENDED QUICKER AGAIN. ECMWF IS
A LOT QUICKER...BRINGING QPF OVER MOST OF UPR MICHIGAN BY 12Z
SATURDAY...AND BASED ON 1000-500MB THICKNESS/H85 TEMPS IS SHOWING
BETTER SHOT AT MIXED PRECIPITATION. KIND OF SEEMS LIKE ECMWF IS
SHOWING TWO SEPARATE WAVES OF QPF AND THAT IS WHY IT APPEARS MUCH
FASTER WITH QPF ARRIVAL. POOR RUN-TO-RUN CONSISTENCY CONTINUES WITH
THE SYSTEM. UNTIL CONSISTENCY IMPROVES WILL KEEP WITH CONSENSUS OF
MODELS FOR THIS SYSTEM FOR POPS. ENOUGH OF A SIGNAL FROM MODELS OVER
LAST COUPLE DAYS TO GO WITH RAIN AND SNOW FOR PTYPE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 129 AM EDT MON APR 1 2013
INCREASINGLY COLDER AIR MOVING ACROSS LAKE SUPERIOR IN NW FLOW WILL
SUSTAIN PERIODS OF LAKE EFFECT SNOW SHOWERS AND MVFR CONDITIONS INTO
MONDAY AT ALL 3 TAF SITES. GUSTY NW WINDS TO 25 KTS AT TIMES COULD
ALSO CONTRIBUTE TO LOWER IFR VSBYS IN SNOW AND BLOWING SNOW...MAINLY
AT MORE EXPOSED KCMX SITE. WINDS BACKING A BIT MORE TO THE
WNW...SHOULD REDUCE CHCS FOR LAKE EFFECT SNOW SHOWERS AT KSAW BY
MONDAY AFTERNOON...PERHAPS EVEN LEADING TO VFR CONDITIONS BY MONDAY
EVENING. ARRIVAL OF DRIER NEAR SFC AIR SHOWN ON THE 00Z INL RAOB WILL
ALSO BRING ABOUT LONG PERIODS OF VFR CONDITIONS AT IWD. THE
COMBINATION OF THE DRYING AND DAYTIME HEATING THIS AFTN WILL DIMINISH
THE LES INTENSITY AT CMX AS WELL.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 451 PM EDT SUN MAR 31 2013
STRONG NORTH TO NORTHWEST GALES TO 45 KTS INTO EARLY THIS EVENING
AS COLD FRONT CROSSES LK SUPERIOR. STRONGEST WINDS OCCUR THROUGH
LATE EVENING IN CORRIDOR FROM CNTRL LK SUPERIOR BUOY TO STANNARD
ROCK AND ACROSS REST OF EASTERN LK SUPERIOR. GALES CONTINUE THROUGH
MONDAY AND MONDAY NIGHT OVER SAME AREAS...BUT NOT QUITE AS STRONG.
WINDS DIMINISH TO LESS THAN 25 KTS BY WEDNESDAY MORNING AS BRIEF
RIDGING MOVES ACROSS. STRONGER SOUTHWEST WINDS TO 30 KTS THEN
EXPECTED WEDNESDAY NIGHT AND THURSDAY MORNING AS LOW PRESSURE
CROSSES NORTHERN ONTARIO AND DRAGS COLD FRONT ACROSS LK SUPERIOR.
NORTHWEST WINDS TO 25 KTS DEVELOP BEHIND THE FRONT INTO NEXT
WEEKEND. THE STRONG WINDS WILL DRAW MUCH COLDER AIR INTO THE UPPER
LAKES EARLY THIS WEEK RESULTING IN FREEZING SPRAY THROUGH TUESDAY
NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR MIZ006-
007-085.
LAKE SUPERIOR...
GALE WARNING UNTIL 6 AM EDT TUESDAY FOR LSZ250-251-266-267.
GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR LSZ244-245-264-265.
GALE WARNING UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ249.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...VOSS/KC
MARINE...JLA
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1145 PM EDT SUN MAR 31 2013
.AVIATION...
//DISCUSSION...
LOWER VFR STRATUS WILL CONTINUE TO FUNNEL ACROSS SOUTHEAST MICHIGAN
OVERNIGHT IN THE WAKE OF A STRONG COLD FRONTAL PASSAGE. RECENT
OBSERVATIONS DO INDICATE THAT A BRIEF MVFR CEILING MAY EMERGE...BUT
CURRENT TRENDS SHOW TOO LIMITED OF COVERAGE AND DURATION TO WARRANT
A MENTION AT THIS STAGE. SOLID NORTHWEST GRADIENT IN PLACE WITH
10-15 KNOT SPEEDS PERSISTING THROUGH THE NIGHT. THE DEGREE OF COLD
AIR ADVECTION WILL PROVIDE SOME DEPTH TO THE MIXED LAYER...YIELDING
THE OCCASIONAL 20 KNOT GUST THROUGH THE EARLY MORNING. CEILINGS
GRADUALLY CLIMB MONDAY...SETTLING INTO THE 5-6K FT RANGE WITH
DIURNAL HEATING BY THE AFTERNOON. GUSTY NORTHWEST WINDS FOR
MONDAY AFTERNOON...PEAK GUST POTENTIAL IN THE 25-28 KNOT RANGE.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILINGS AT LEAST INTERMITTENTLY FALLING BELOW
5000 FEET THROUGH THE MORNING HOURS MONDAY.
&&
.PREV DISCUSSION...ISSUED 339 PM EDT SUN MAR 31 2013
SHORT TERM...THROUGH TONIGHT
DEEPENING LOW PRESSURE SYSTEM OVER THE NORTHERN GREAT LAKES SENT A
WEAK TROUGH/COLD FRONTAL BOUNDARY THROUGH THE AREA THIS MORNING WITH
LITTLE IN THE WAY OF PRECIP ASSOCIATED WITH IT. IMPRESSIVE DRY SLOT
BEHIND THE TROUGH WITHIN A REGION OF DEEP MIXING HAS CLEARED OUT
MOST OF THE CLOUDS ALLOWING TEMPS TO SPIKE INTO THE MID 50S. THE
DEEP MIXING HAS ALSO PRODUCED GUSTS TO AROUND 20 KNOTS THIS
AFTERNOON. A STRONGER TROUGH/FRONT WILL GET SENT THROUGH THE REGION
THIS EVENING. MODELS INDICATE STEEP LOW LEVEL LAPSE RATES AND CAPE
VALUES BETWEEN 50-100 J/KG WITH A NARROW BAND OF THETA E JUST AHEAD
OF THE TROUGH. THEY ALSO SHOW FAIRLY LOW PWATS TIED IN THE LOW
LEVELS BRIEFLY SPIKING WITH THE THETA E AXIS BUT DRYING OUT RAPIDLY
BEHIND THE TROUGH. THE HRRR AND HIRES WRF BOTH SHOW A PERIOD OF
SHOWERS...RAIN BECOMING A MIX OF RAIN AND SNOW...BETWEEN 00Z AND 06Z
WITH POSSIBLE FLURRIES OR LIGHT SNOW SHOWERS AFTER THAT. AN AREA OF
PRECIP IS CURRENTLY SHOWING UP ON REGIONAL RADAR WITHIN THE TROUGH
SO BESIDES FINE TUNING SOME TIMING ISSUES...SEE NO REASONS TO CHANGE
MUCH WITH THE OVERNIGHT POPS/WX. WITH THE POSSIBLE CONVECTIVE NATURE
OF THE PRECIP AND LONGER DURATION...WILL LEAVE A FEW TENTHS OF SNOW
ACCUMULATIONS TO THE NORTH. WINDS WILL STAY ELEVATED OVERNIGHT WHICH
WOULD TYPICALLY LEAD TOWARD WARMER MIN TEMPS BUT CAA BEHIND THE
TROUGH WILL DROP 850MB TEMPS FROM +1C TO -11C OVERNIGHT. DEWPOINTS
UPSTREAM IN THE TEENS WILL TRY TO WORK THEIR WAY INTO THE SAGINAW
VALLEY AS WELL SO WE WILL STILL COOL OFF QUITE A BIT TONIGHT.
LONG TERM... MONDAY THROUGH NEXT SUNDAY
POLAR AIR NOW INFILTRATING THE UPPER MS VALLEY WILL BE OVER THE
GREAT LAKES REGION BY MONDAY MORNING. THIS AIRMASS IS ASSOCIATED
WITH A POLAR VORTEX NOW LOCATED OVER NRN ONTARIO. THIS UPPER LOW IS
FORECAST TO DEEPEN AS IT TRACKS NORTHEAST OF LAKE HURON AND INTO
QUEBEC ON MONDAY AND WILL REMAIN RATHER PROGRESSIVE...LIFTING INTO
NEWFOUNDLAND BY MIDWEEK. BY 12Z MON...850MB TEMPS ARE STILL FORECAST
TO PLUNGE TO -12 TO -14C OVER SE MI. WEAK MID LEVEL IMPULSES
TRACKING INTO THE REGION TUES/TUES NIGHT WILL HOLD SOME DEGREE OF
MID LEVEL TROUGHING OVER THE GREAT LAKES...WITH SE MI REMAINING
FIRMLY WITHIN THE LOW LEVEL THERMAL TROUGH. DESPITE SOME INTERVALS
OF SUN AND MIXING HEIGHTS EXTENDING UP TO 800MB...THE DEPTH OF COLD
AIR WILL REMAIN SUPPORTIVE OF DAYTIME HIGHS MON AND TUES MAINLY IN
THE 30S. NIGHTTIME MINS ARE EXPECTED TO DROP OFF INTO THE 20S
/POSSIBLY SOME TEENS IF THE BOUNDARY LAYER CAN DECOUPLE/. THESE
TEMPS ARE A GOOD 10 TO 15 DEGREES BELOW SEASONAL AVERAGES. W-NW
WINDS WILL BE QUITE GUSTY ON MONDAY AS DEEPENING SFC LOW PRESSURE
OVER QUEBEC SUSTAINS A TIGHT LOW LEVEL GRADIENT OVER THE REGION.
SOME GUSTINESS TO THE WINDS IS LIKELY TO HOLD THROUGH MUCH OF
TUESDAY AS THE LAKE AGGREGATE MAINTAINS A HEALTHY GRADIENT OVER SRN
LOWER MI. THIS WILL PUT WIND CHILL READINGS IN THE TEENS AND 20S MON
AND TUES.
THE STEEP LOW LEVEL LAPSE RATES COURTESY OF THE COLD AIR WILL ALLOW
A DIURNAL ENHANCEMENT TO THE CLOUDS MON AND TUES AFTERNOON. THE CORE
OF THE MID LEVEL COLD POOL WILL HOWEVER TRACK TO THE NORTHEAST OF
THE FORECAST AREA...THUS KEEPING CONVECTIVE CLOUD DEPTHS RATHER
SHALLOW UNDER A MID LEVEL INVERSION. THIS ALONG WITH SUBSTANTIAL LOW
LEVEL DRY AIR ADVECTION WILL SUPPORT JUST SCATTERED SNOW SHOWERS ON
MONDAY. THE 12Z MODEL SUITE DO SHOW A MID LEVEL IMPULSE /NOW LOCATED
OVER FAR NORTHERN CANADA/ DIVING INTO THE WESTERN GREAT LAKES LATE
TUES. THE CURRENT MODEL SUITE SUGGEST THIS FEATURE WILL ARRIVE INTO
SE MI TOWARD THE END OF THE DIURNAL CYCLE...WHICH SUPPORTS HOLDING
ONTO THE DRY FORECAST AT THIS TIME.
A SPLIT FLOW PATTERN IS FORECAST ACROSS NORTH AMERICA BY MID-LATE
NEXT WEEK...WITH A FAST MOVING NORTHERN STREAM WAVE EXPECTED TO
BRING A COLD FRONT INTO SRN MI IN THE THURS NIGHT/FRIDAY TIME FRAME.
STEADY WARM AIR ADVECTION WILL ALLOW TEMPS TO RISE BACK UP INTO THE
50S ON THURSDAY PRIOR TO THE COLD FRONT PASSAGE. WHILE THE MEDIUM
RANGE MODEL SUITE ARE IN GOOD AGREEMENT IN SHOWING A STRONG LOWER
TROPOSPHERIC BAROCLINIC ZONE SETTING UP ACROSS THE NRN PLAINS AND
GREAT LAKES REGION BY NEXT WEEKEND...THERE IS CONSIDERABLE
DIFFERENCES WITH RESPECT TO THE TIMING AND AMPLITUDE OF MID LEVEL
SHORT WAVE ENERGY EMANATING FROM THE PACIFIC AND TRACKING ALONG THE
BAROCLINIC ZONE. LARGE SPREAD AMONG ENSEMBLE MEMBERS ADDS TO THE
UNCERTAINTY. THERE IS HOWEVER ENOUGH CONFIDENCE TO CARRY A CHANCE OF
PRECIP NEXT WEEKEND.
MARINE...
DEEPENING LOW PRESSURE SYSTEM OVER THE NORTHERN GREAT LAKES WILL
DROP THE SECOND OF TWO SURFACE TROUGHS THROUGH THE GREAT LAKES THIS
EVENING...USHERING A MUCH COLDER AIRMASS INTO THE REGION. STRONG
WESTERLY WINDS WILL VEER TO THE NORTHWEST BEHIND THIS TROUGH AND
INCREASE WITH A TIGHTENING PRESSURE GRADIENT...ESPECIALLY OVER THE
NORTHERN HALF OF LAKE HURON OVERNIGHT. A GALE WARNING HAS BEEN
ISSUED FOR THE OPEN WATERS OF NORTHERN LAKE HURON WITH SMALL CRAFT
ADVISORIES FOR ALL NEARSHORE WATERS OF LAKE HURON. WINDS WILL REMAIN
ELEVATED THROUGH MONDAY NIGHT.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
GALE WARNING...LHZ361-LHZ362-LHZ363-LHZ462...UNTIL 10 PM MONDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT
HURON INCLUDING OUTER SAGINAW BAY...UNTIL 8 AM TUESDAY.
SMALL CRAFT ADVISORY...INNER SAGINAW BAY...UNTIL 10 PM MONDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....MR
SHORT TERM...DRK
LONG TERM....SC
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS JACKSON MS
1025 PM CDT SUN MAR 31 2013
.UPDATE...A DENSE FOG ADVISORY HAS BEEN ISSUED FOR THE FORECAST AREA
FOR TONIGHT. MANY AREAS OF DENSE FOG HAVE DEVELOPED AND WITH LIGHT
WINDS AND NO CLOUD COVER EXPECTED TO DEVELOP FOG COVERAGE IS
EXPECTED TO INCREASE OVERNIGHT. TEMPERATURES HAVE ALSO BEEN TWEAKED
SLIGHTLY. &&
.PREV DISCUSSION...
TODAY THROUGH EARLY WEDNESDAY
WEAKENING SQUALL LINE PUSHING THROUGH THE REGION TO THE SOUTHEAST
TONIGHT WITH QUIETER WEATHER MONDAY AND TUESDAY BEFORE MORE RAIN FOR
MIDDLE TO LATE WEEK.
SEVERAL REPORTS OF TREES AND POWERLINES DOWN HAVE COME IN FROM
NORTHEAST LA AND WEST MS AS THE ONCE STRONGER SQUALL LINE MOVED
THROUGH. HOWEVER, AN OVERALL WEAKENING TREND OVER THE PAST HOUR AS
BEEN OBSERVED AS IT ENCOUNTERS A LESS FAVORABLE AIRMASS TO THE EAST.
WARMING CLOUD TOPS VIA IR SAT AND WEAKENING REFLECTIVITY GRADIENT
FURTHER SUGGEST MCS IS BECOMING COLD POOL DOMINATED WHILE BEING
FARTHER REMOVED FROM LARGER SCALE FORCING. HAVE CANCELED PORTIONS OF
THE SEVERE TSTORM WATCH TO THE WEST OF THE CURRENT LINE. THE BEST
ENVIRONMENT FOR MARGINAL STRONG TO BRIEFLY SEVERE STORMS IS ACROSS
FAR S/SE AREAS WHERE RAP OUTPUT SUGGEST 500-1000 J/KG SBCAPE AND ~30
KT ORGANIZATIONAL DEEP LAYER SHEAR. HOWEVER, FEEL THE COLD POOL
DOMINATION AND LACK OF FORCING SHOULD KEEP MOST STORMS IN CHECK FROM
BEING SEVERE ACROSS THE REMAINDER OF THE AREA. BUT ONE OR TWO STORMS
COULD BRIEFLY BECOME SEVERE ACROSS THIS AREA TROUGH EARLY EVENING.
AS THE TSTORM LINE AND CLOUDS CLEAR TONIGHT FROM THE NORTH,
DEVELOPMENT OF FOG WILL BE LIKELY ACROSS A MAJORITY OF THE REGION.
SOME ISOLATED LOCATIONS OF DENSE FOG ARE PSBL TONIGHT THROUGH 8AM
TOMORROW MRNG. FOG WILL DISSIPATE THROUGH 9AM AS MIXING STEADILY
INCREASES.
THE WEAKENING TSTORM LINE WAS INITIATED ON A LOW-LVL FRONTAL
BOUNDARY AND A NRN STREAM H5 S/WV TROUGH PIVOTING ACROSS THE LOWER
PLAINS. THIS FRONTAL BOUNDARY WILL STALL ALONG THE I-10 TO HIGHWAY
84 CORRIDOR SECTOR OVERNIGHT AND MONDAY. ANOTHER QUICK MOVING
IMPULSE IN THE NW FLOW MAY HELP SOME SHOWERS LINGER THROUGH THE
EARLY MRNG HOURS ACROSS FAR SOUTHERN LOCATIONS. THIS BOUNDARY WILL
SERVE AS A IMPETUS FOR A FEW SHOWERS AND THUNDERSTORMS MON AFTN ALSO
AS DIURNALLY DRIVEN INSTABILITY BUILDS INVOF GREATEST SFC
CONVERGENCE. MAV POPS CAME IN QUITE LOW DESPITE GFS HOLDING UP THE
FRONT ACROSS THIS REGION. THE EC AND NAM ARE IN AGREEMENT OF
DIURNALLY DRIVEN QPF ALSO. THEREFORE, BUMPED POPS UP ACROSS SRN TIER
OVER MAV. FOR CNTRL AND NORTH AREAS HOWEVER, BUFR SOUNDINGS SUGGEST
AMPLE SUN WITH TEMPS RISING INTO THE MID 70S AS SFC HIGH PRESSURE
AXIS NOSES IN.
THE SFC HIGH PRESSURE WILL ALSO AID IN A REINFORCING SHOT OF
COOLER/DRIER AIR IN THE LOW LEVELS TUESDAY MRNG THAT WILL QUELL
TEMPS FROM REACHING MONDAY`S LEVELS. MID AND HIGH LEVEL CLOUDS WILL
BE ON THE INCREASE TUESDAY INTO TUESDAY NIGHT AS OUR NEXT SYSTEM
TAKES SHAPE ACROSS THE INTER-MOUNTAIN WEST. A SUPPRESSED PACIFIC H5
S/WV TROUGH WILL SWING ACROSS THE FOUR CORNERS REGION LATE TUESDAY
AND HELP SFC LOW CYCLOGENESIS ACROSS TEXAS. A DECENT PRESSURE
GRADIENT APPEARS TO BE IN PLACE GOING INTO TUES NIGHT WITH SFC HIGH
JUST OFF TO NORTH AND THE DEVELOPING SFC LOW. SMALL PERTURBATIONS/
IMPULSES IN THE H5 FLOW WILL MOVE OVER TOP THE ARKLAMISS LATE TUES
INTO EARLY WEDS AIDING IN ISENTROPIC ASCENT. LIGHT SHOWER ACTIVITY
WILL BE ON THE INCREASE LATE TUES NIGHT INTO WED MRNG FOR WESTERN
AND CENTRAL ARKLAMISS AREAS.
FOR FORECAST ELEMENTS...WINDS WERE BUMPED UP IN ASSOCIATION WITH THE
TSTORM COMPLEX. MAV POPS WERE BUMPED DOWN DRAMATICALLY TONIGHT THEN
SLIGHTLY UP FOR SOUTHERN AREAS DAY PERIOD MONDAY. FOG WAS ADDED TO
THE OVRNGT PERIOD ALSO. MAV POPS WERE GENERALLY FOLLOWED TUESDAY
NIGHT INTO WEDNESDAY. MAV TEMPS WERE DROPPED A TOUCH FOR NRN AREAS
TOMORROW GIVEN BUFR SOUNDINGS AND MAX HEATING POTENTIAL. /ALLEN/
&&
.AVIATION...AREAS OF IFR/MVFR CLOUD DECKS AND IFR/LIFR CONDITIONS IN
FOG WILL CONTINUE THIS EVENING. FOG WILL BE ON THE INCREASE WITH
WIDESPREAD IFR/LIFR CIGS/VSBYS DUE TO FOG. FOG WILL CLEAR AND LOW
CLOUDS WILL LIFT BY 14Z MONDAY FOR VFR CONDITIONS BY LATE MORNING.
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...DENSE FOG ADVISORY UNTIL 9 AM CDT MONDAY FOR MSZ018-019-025>066-
072>074.
LA...DENSE FOG ADVISORY UNTIL 9 AM CDT MONDAY FOR LAZ007>009-015-016-
023>026.
AR...DENSE FOG ADVISORY UNTIL 9 AM CDT MONDAY FOR ARZ074-075.
&&
$$
03/ALLEN/15
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
241 AM MDT MON APR 1 2013
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 240 AM MDT MON APR 1 2013
ACTIVE PROGRESSIVE NORTHERN STREAM FLOW WILL DOMINATE
THE WEATHER IN THE PERIOD...WITH A LARGE SCALE SPLIT FLOW REGIME.
THIS WILL OFFER WARM DOWNSLOPE PAC ORIGIN FLOW INTO THE AREA...ESP
TUE. GREAT LAKES UPPER TROUGH WILL SLOWLY SHIFT EAST WITH DEEP LAYER
RIDGING DEVELOPING TODAY...INITIATING WAA BY THIS AFTERNOON OVER THE
WESTERN FA. THE ONLY FORECAST CONCERN TODAY WILL BE THE EVOLUTION OF
THE CURRENT STRATUS IN PLACE ACROSS THE EASTERN FA...WHICH MAY
HAMPER T RISES. THE ONLY FORECAST MODELS WHICH SEEMS TO HAVE ANY
SORT OF HANDLE ON THE EXISTENCE OF CLOUD COVER IS THE RAP AND LOCAL
WRF...WITH ALL OTHER GUIDANCE REMAINING TOO DRY IN THE LL/S.
RAP/LOCAL WRF BOTH INDICATE THAT INCREASING DRY WESTERLY FLOW AT THE
BL TOP SHOULD HELP ERODE CLOUD COVER WEST TO EAST THROUGH MORNING
AND TRIED TO INCORPORATE THIS IDEA INTO THE GRIDS. ONCE CLOUDS
CLEAR...SKIES WILL REMAIN MOSTLY CLEAR THROUGH THE PERIOD...SAVE FOR
SOME PASSING CIRRUS.
TEMPS WILL REMAIN ON THE COOL SIDE ACROSS MOST OF THE AREA
TODAY...WITH THE SD PLAINS BEING THE COOLEST. NE WY WILL SEE QUICK
RESPONSE TO ENSUING WAA WITH MANY PLACES EXPECTED TO BE IN THE 50S
THERE. HAVE ADJUSTED TEMPS UP SOME...GIVEN LATEST BLENDED GUIDANCE
WITH STRONG INSOLATION EXPECTED. MUCH WARMER CONDITIONS EXPECTED
TUE...WITH 50S AND 60S COMMON MOST PLACES. HAVE WARMED MOST PLACES
A FEW DEGREES TUE...ESP NE WY. STRONG INSOLATION SHOULD SUPPORT
SUPERADIABATS AT MOST LOCATIONS GIVEN WEAK LL FLOW...WITH TEMPS
WARMER THAN CURRENT FORECAST HIGHS CERTAINLY POSSIBLE. THE NEXT
NORTHERN STREAM IMPULSE WILL APPROACH THE REGION TUE...WITH WAA
RAMPING UP...AS WELL AS LL SOUTHERLY FLOW TUE NIGHT. THIS SHOULD
KEEP TEMPS UP AT MANY PLACES OVERNIGHT TUE...GIVEN TURBULENT
MIXING...ESP IN THE LEE DOWNSLOPE AREAS OF THE BH.
&&
.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 240 AM MDT MON APR 1 2013
UPPER LEVEL RIDGE FLATTENS LATE WEDNESDAY AS A COLD FRONT CROSSES
THE AREA...BRINGING A CHANCE FOR RAIN SHOWERS AND AN ISOLATED
THUNDERSTORM. RAIN SHOWERS WILL LINGER INTO THURSDAY...MAINLY ACROSS
NORTHERN PORTIONS OF THE AREA. A MORE UNSETTLED PATTERN WILL DEVELOP
BY THE WEEKEND AS A LARGE UPPER TROF DEVELOPS OVER THE WEST COAST
AND A SERIES OF DISTURBANCES MOVE ACROSS THE NORTHERN PLAINS IN WEST
TO SOUTHWEST FLOW. TEMPERATURES WILL GENERALLY STAY ABOVE AVERAGE
LATE IN THE WEEK AND LIKELY DROP CLOSER TO AVERAGE LEVELS DURING THE
WEEKEND.
&&
.AVIATION...FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT
ISSUED AT 240 AM MDT MON APR 1 2013
MVFR AND LOCAL IFR CIGS WILL PERSIST ACROSS WESTERN SOUTH DAKOTA
THROUGH THE MORNING HOURS BEFORE LIFTING AND SHIFTING EAST BY 18Z.
VFR CONDITIONS ARE THEN EXPECTED THROUGH TUESDAY MORNING.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...JC
LONG TERM...15
AVIATION...15
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
311 AM CDT MON APR 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 311 AM CDT MON APR 1 2013
A BROAD/DEEP MID TO UPPER LEVEL TROUGH HAS SET UP ACROSS
SOUTHEASTERN CANADA WHILE AN AMPLIFYING RIDGE DEVELOPS ACROSS THE
WESTERN US. AT THE SURFACE...CYCLONIC FLOW PERSISTS ACROSS THE
GREAT LAKES AND UPPER MISSISSIPPI RIVER VALLEY AS A RIDGE OF HIGH
PRESSURE PUSHES DOWN TO THE SOUTHEAST ACROSS THE DAKOTAS. SKIES
HAVE MAINLY CLEARED OUT THOUGH A FEW CU STREAKS HAVE STUCK AROUND
NORTHERN WISCONSIN. SHOULD NOT SEE MUCH IN THE WAY OF CHANGES IN
THE PATTERN FOR TODAY AS THE RIDGE UNDERCUTS THE REGION TO THE
SOUTHWEST AND STRONGLY SUBSIDENT AIR SHOULD KEEP SKIES MAINLY
CLEAR.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 311 AM CDT MON APR 1 2013
WITH 850MB TEMPERATURES STAYING BETWEEN -10C TO -15C INTO
WEDNESDAY MORNING...TEMPERATURES WILL STAY WELL BELOW NORMAL OVER
THIS PERIOD. THE COLDEST MORNING WILL LIKELY BE ON WEDNESDAY
MORNING AS THE CORE OF THE RIDGE MOVES OVERHEAD AND ALLOWS FOR
IDEAL RADIATIONAL COOLING WITH CLEAR SKIES AND LIGHT WINDS. THINK
THAT SOME OF THE MODELS ARE LEANING TOWARD CLIMO AND HAVE SOME
HIGHER VALUES IN THERE...SO HAVE UNDERCUT LOWS THERE A BIT FOR
WEDNESDAY MORNING. TEMPERATURES WILL BE ON THE INCREASE ON
WEDNESDAY AS THE RIDGE AXIS MOVES IN FROM THE WEST AND 850MB
TEMPERATURES IMPROVE TO AROUND -2C TO 0C. HIGH TEMPERATURES WILL
STILL BE BELOW NORMAL BUT AT LEAST WILL BE TRENDING IN THE RIGHT
DIRECTION.
A MID LEVEL TROUGH WILL THEN TRACK ACROSS SOUTHERN CANADA
WEDNESDAY NIGHT INTO THURSDAY AND IN TURN BRING A SURFACE LOW
ALONG WITH IT. A COLD FRONT WILL EXTEND SOUTH OF THIS LOW AND WILL
APPROACH CENTRAL MINNESOTA/NORTHERN WISCONSIN EARLY THURSDAY
MORNING. THE BETTER LIFT/MOISTURE CONVERGENCE STILL APPEARS TO BE
OFF TO THE NORTHEAST CLOSER TO THE MID LEVEL/SURFACE LOW...SO IT
DOES NOT LOOK LIKE THERE SHOULD BE MUCH PRECIPITATION THAT OCCURS
ALONG/AHEAD OF THE COLD FRONT. THERMAL PROFILES OFF OF THE 01.00Z
GFS SUGGEST THAT THE PRECIPITATION SHOULD MAINLY FALL AS LIGHT
RAIN...BUT CAN NOT RULE OUT THAT THERE COULD BE SOME SNOW THAT
MIXES IN AS THE PROFILE SATURATES DOWN TO THE WET BULB TEMPERATURE.
THE FOCUS THEN GOES TO A MORE POTENT SYSTEM THAT WILL BE
DEVELOPING IN THE CENTRAL PLAINS ON FRIDAY WITH THE AFOREMENTIONED
COLD FRONT TRANSITIONING TO A WARM FRONT. THE INITIAL QUESTION
REMAINS WITH HOW FAR NORTH THAT FRONT MAKES IT NEXT WEEKEND AS
TEMPERATURES WILL LIKELY BE IN THE 60S TO THE SOUTH OF IT AND IN
THE 30S WITH SNOW TO THE NORTH OF IT. THE ECMWF HAS FLIP FLOPPED
AROUND A BIT THE PAST FEW DAYS WITH THE TRACK OF THE SURFACE LOW
THAT EVENTUALLY COMES THROUGH THE REGION ON SUNDAY WHILE THE GFS
HAS BEEN FAIRLY STEADY WITH ITS TRACK. A FEW OF THE ECMWF RUNS
HAVE TAKEN A MORE NORTHERLY TRACK THROUGH SOUTHERN
MINNESOTA/CENTRAL WISCONSIN WHILE THE GFS HAS BEEN FAIRLY
CONSISTENT WITH TAKING THE LOW THROUGH IOWA. PRECIPITATION WILL
INITIALLY START OUT WELL AHEAD OF THIS LOW AS WARM AIR
ADVECTION/FRONTOGENESIS STRENGTHENS ALONG THE THERMAL GRADIENT. A
LOT OF DETAILS TO BE WORKED OUT AND HAVE BASICALLY DONE A BLEND
BETWEEN THE 01.00Z GFS/ECMWF WITH THIS SYSTEM BUT SOME DRASTIC
CHANGES COULD BE IN STORE DEPENDING ON WHETHER WE END UP IN THE
WARM OR COLD SECTOR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
1148 PM CDT SUN MAR 31 2013
SURFACE HIGH PRESSURE WILL BUILD SOUTHEAST FROM THE NORTHERN
PLAINS INTO THE UPPER MISSISSIPPI RIVER VALLEY THROUGH THE TAF
PERIOD. NORTHWEST WINDS WILL CONTINUE INTO THE 10 TO 15 KNOT
RANGE THROUGH 00Z TUESDAY...THEN DIMINISH AS THE SURFACE HIGH
SPREADS EASTWARD INTO THE AREA. SOME PATCHES OF MVFR CLOUDS SEEN
ON SATELLITE ACROSS NORTHERN MINNESOTA. MODELS...ESPECIALLY THE
NAM AND RAP ARE BOTH OVERDOING THE CURRENT MOISTURE FIELD. DID
MENTION SCATTERED CLOUDS WITH BASES BETWEEN 020-030K FEET AFTER
11Z AT KRST AND 15Z AT KLSE. THIS WILL THEN DISSIPATE AFTER 00Z
TUESDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1148 PM CDT SUN MAR 31 2013
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
321 PM CDT SUN MAR 31 2013
AT 3 PM...A CANADIAN COLD FRONT EXTENDED FROM TRAVERSE CITY MICHIGAN
TO COLUMBIA MISSOURI. ANOTHER MUCH STRONGER CANADIAN COLD FRONT EXTENDED
FROM IRONWOOD MICHIGAN TO MANKATO MINNESOTA. SCATTERED RAIN AND
SNOW SHOWERS WERE DEVELOPING AHEAD OF THIS SECOND FRONT ACROSS
WESTERN WISCONSIN. WITH 925-800 MB LAPSE RATES RUNNING AROUND 8C/KM...
THE STRONGER WINDS FROM ALOFT ARE MIXING DOWN TO THE SURFACE. JUST
IN THE PAST HOUR...THE WINDS HAVE BEEN GUSTING INTO THE 30 TO
35 MPH RANGE ACROSS NORTHEAST IOWA AND SOUTHEAST MINNESOTA. THE
STRONGEST WIND GUST /36 MPH/ WAS A MAYO HELIPAD IN ROCHESTER
MINNESOTA. THESE WIND GUST WILL QUICKLY WANE EARLY THIS EVENING
WITH THE LOSS OF DIURNAL HEATING.
FOR LATE TONIGHT AND MONDAY...THE 31.12Z NAM/WRF SHOWS THAT SOME
OF THE CLOUDS ACROSS NORTHERN MINNESOTA...WESTERN ONTARIO...AND
EASTERN MANITOBA WILL MOVE SOUTHEAST TOWARD THE FORECAST AREA. IN
ADDITION WITH CONVECTIVE TEMPERATURE IN THE MID TO UPPER
20S...THIS WOULD ALSO FAVOR THE DEVELOPMENT OF A SCATTERED TO
BROKEN DECK OF CUMULUS CLOUDS. IN ADDITION...THE 31.12Z NMM WOULD
SUGGEST THE POSSIBILITY OF A FEW SNOW SHOWERS ACROSS TAYLOR COUNTY
AND THE NORTHERN PORTIONS OF CLARK COUNTY IN CENTRAL AND NORTH CENTRAL
WISCONSIN. SINCE THIS IS THE ONLY MODEL SHOWING THIS...KEPT THE
FORECAST DRY FOR NOW.
ON TUESDAY AFTERNOON...THE MODELS CONTINUE TO SHOW THAT ANOTHER
SHORT WAVE TROUGH MOVE THROUGH THE NORTHERN AND EASTERN PORTIONS
OF WISCONSIN. THE SOUNDINGS SHOW A SLIGHT SATURATION OCCURRING
BETWEEN 850 AND 700 MB. WITH THE 270-280K ISENTROPIC CONDENSATION
PRESSURE DEFICITS GREATER THAN 100 MB NOT EXPECTING VERY MANY
CLOUDS OR PRECIPITATION FROM THIS SYSTEM.
ON WEDNESDAY...THE MODELS CONTINUE TO SLOW THE EASTWARD
PROGRESSION OF A FRONT MOVING TOWARD THE AREA FROM THE NORTHERN
PLAINS. DUE TO THIS...THE PRESSURE GRADIENT IS NOT AS TIGHT AND
THE AREA DOES NOT MIX AS DEEP. AS RESULT...COOLED THE HIGH
TEMPERATURES A FEW DEGREES.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
321 PM CDT SUN MAR 31 2013
ON THURSDAY...A FRONT WILL MOVE THROUGH THE AREA. IT CONTINUES TO
LOOK LIKE THE BEST SYNOPTIC AND ISENTROPIC LIFT AND THE BEST 925
TO 850 MB MOISTURE TRANSPORT WILL BE MAINLY TO OUR NORTHWEST. THE
GFS CONTINUES TO SHOW THAT THIS FRONT WILL PRODUCE A BAND OF
PRECIPITATION AS IT PROGRESSES SOUTHEAST ACROSS THE AREA.
MEANWHILE THE GEM AND ECMWF SHOW THAT THIS PRECIPITATION WILL
DEVELOP NORTH OF INTERSTATE 94 DURING THE MORNING AND THEN MOVES
THROUGH THE REMAINDER OF THE AREA DRY DURING THE AFTERNOON.
OVERALL PREFER THE ECMWF AND GEM SOLUTIONS DUE TO THE LACK OF
MOISTURE TRANSPORT DURING THE AFTERNOON...AND THAT THE GFS HAS
BEEN HAVING A LOT OF ISSUES WITH ITS LOW LEVEL MOISTURE DURING THE
PAST MONTH.
FROM FRIDAY AFTERNOON THROUGH THE UPCOMING WEEKEND...THE MODELS
CONTINUE TO STRUGGLE WITH THEIR TIMING AND LOCATION OF A SERIES OF
LOW PRESSURE SYSTEMS MOVING THROUGH THE REGION. MUCH OF THIS IS
HOW THEY HAVE BEEN TRYING TO DEVELOP A TROUGH OVER THE WESTERN
UNITED STATES AND A RIDGE OVER THE CENTRAL UNITED STATES. OVER THE
PAST DAY...THE MODELS HAVE BEEN SLOWING THIS DEVELOPMENT AND THIS
HAS KEPT OUR AREA MORE IN ZONAL FLOW ALOFT. AS A RESULT...THE
TEMPERATURES HAVE BEEN COOLING OVER THE PAST 4 MODEL RUNS. AS A
RESULT...HAD TO INTRODUCE MORE SNOW INTO THE FORECAST FOR THIS
TIME PERIOD. WITH THE FIRST SYSTEM /FRIDAY AFTERNOON THROUGH
SATURDAY/...THE GFS IS PRODUCING A 6 TO 12 INCH BAND OF SNOW ALONG
AND NORTH OF INTERSTATE 94. MEANWHILE THE ECMWF HAS A 3 TO 6 INCH
BAND OF SNOW ACROSS FAR NORTHERN WISCONSIN AND UPPER MICHIGAN. THE
GFS THEN MOVES YET ANOTHER LOW PRESSURE SYSTEM INTO SOUTHEAST
MINNESOTA...NORTHEAST IOWA...AND SOUTHWEST WISCONSIN ON SATURDAY.
THE ECMWF ALSO SHOWS ANOTHER LOW PRESSURE SYSTEM...BUT IT DOES NOT
AFFECT THE AREA UNTIL MONDAY. THE TEMPERATURES ALOFT LOOK A BIT
WARMER...SO THE PRECIPITATION WITH THIS SYSTEM LOOKS TO BE IN THE
FORM OF RAIN.
&&
.AVIATION...THROUGH 06Z TUESDAY
1148 PM CDT SUN MAR 31 2013
SURFACE HIGH PRESSURE WILL BUILD SOUTHEAST FROM THE NORTHERN
PLAINS INTO THE UPPER MISSISSIPPI RIVER VALLEY THROUGH THE TAF
PERIOD. NORTHWEST WINDS WILL CONTINUE INTO THE 10 TO 15 KNOT
RANGE THROUGH 00Z TUESDAY...THEN DIMINISH AS THE SURFACE HIGH
SPREADS EASTWARD INTO THE AREA. SOME PATCHES OF MVFR CLOUDS SEEN
ON SATELLITE ACROSS NORTHERN MINNESOTA. MODELS...ESPECIALLY THE
NAM AND RAP ARE BOTH OVERDOING THE CURRENT MOISTURE FIELD. DID
MENTION SCATTERED CLOUDS WITH BASES BETWEEN 020-030K FEET AFTER
11Z AT KRST AND 15Z AT KLSE. THIS WILL THEN DISSIPATE AFTER 00Z TUESDAY.
&&
.HYDROLOGY...TODAY AND TONIGHT
1235 PM CDT SUN MAR 31 2013
MANY RIVERS HAVE CLIMBED OVER THE PAST FEW DAYS DUE TO RECENT SNOW
MELT AND THE RAIN THAT FELL ON SATURDAY WHICH GENERALLY TOTALED UP
TO BETWEEN A QUARTER AND THREE QUARTERS OF AN INCH. THERE HAVE
BEEN REPORTS OF SOME ROADS BEING CLOSED DUE TO HIGH WATER...
PARTICULARLY IN PORTIONS OF SOUTHEAST MINNESOTA WHERE THERE HAD
BEEN QUITE A BIT OF SNOW STILL ON THE GROUND LEADING UP TO THIS
WEEKEND. APPEARS THAT HIGH WATER LEVELS ARE PAST THEIR PEAKS OVER
NORTHEAST IA AND SOUTHWEST WI...AND ARE RIGHT AROUND THEIR PEAK
NOW FOR SOUTHEAST MN. WITH THE COOLER WEATHER MOVING IN...
ANTICIPATE THAT THE RUNOFF WILL SLOW AND CEASE...ALLOWING THIS
WATER TO MOVE OFF DOWNSTREAM.
WILL CONTINUE TO MONITOR THE RIVERS CLOSELY. REFER TO THE LATEST
STATEMENTS FOR UP-TO-DATE INFO.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
321 PM CDT SUN MAR 31 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...RABERDING
HYDROLOGY....MW
AREA FORECAST DISCUSSION
NWS PUEBLO CO
421 AM MDT MON APR 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 420 AM MDT MON APR 1 2013
A SHORTWAVE TROF IS WRAPPING AROUND AN UPR LOW THAT IS OVR THE WRN
STATES...AND IS BRINGING CLOUDS AND SOME PCPN TO PORTIONS OF WRN
CO...SOME OF WHICH WL AFFECT THE CONTDVD THIS MORNING. ALSO THIS
MORNING A FRONT IS CONTINUING TO MOVE SOUTHWARD THROUGH THE SERN
PLAINS AS OF 3AM IT HAD MOVED SOUTH OF THE ARKANSAS RIVER VALLEY.
HAVE SEEN SOME STRATUS DEVELOP BEHIND THIS FRONT IN NE AND PORTIONS
OF NWRN KS. THE HRRR AND NAM12 SHOW LOW LEVEL RH VALUES/STRATUS
BACKING INTO THE FAR SERN PLAINS A LITTLE LATER THIS MORNING...AND
MAYBE BACKING INTO THE FAR ERN PORTIONS OF EL PASO COUNTY. THE NAM
AND THE HRRR KEEP THE FAR SERN PLAINS DRY THRU THE MORNING
HOURS...WHILE THE GFS PRINTS OUT SOME LIGHT QPF ASSOCIATED WITH THE
STRATUS. DO NOT FEEL THAT MEASURABLE PCPN WL OCCUR SO WL KEEP THE
FORECAST DRY OUT EAST...AND WL ONLY HAVE POPS ALONG THE CONTDVD THIS
MORNING. THIS AFTERNOON THE NAM AND GFS SHOW THE BEST PCPN CHANCES
BEING OVR THE CENTRAL CO MTS AND OVR PIKES PEAK AND TELLER COUNTY.
THE NSSL WRF SHOWS PCPN IN THESE AREAS AS WELL...BUT ALSO SHOWS A
BAND OF PCPN MOVING FROM THE SW ACRS THE SWRN MTS...THE SAN LUIS
VALLEY...THE SANGRE DE CRISTO MTS...AND THEN ONTO THE ADJACENT I-25
CORRIDOR BY EARLY EVENING...AND THEN MOVING ACRS THE SERN PLAINS
THRU THE EVENING. WL LEAN CLOSER TO THE WRF`S SOLUTION. SHOULD SEE
SOME LIGHT SNOW ACCUMS OVR THE HIGHEST ELEVATIONS. TEMPS TODAY WL BE
COOLER THAN YESTERDAY OVR THE SERN PLAINS IN THE WAKE OF THE
FRONT...BUT GUIDANCE TEMPS ARE NOT IN GOOD AGREEMENT SO WL SPLIT THE
DIFFERENCE. COULD SEE SOME LOW CLOUDS HANGING AROUND OVR THE FAR
SERN CORNER INTO THE AFTERNOON WHICH WOULD KEEP TEMPS EVEN COOLER
OUT THERE. SOME WRN AREAS WL BE A LITTLE COOLER TODAY...WHILE THE
SAN LUIS VALLEY WL LIKELY SEE TEMPS SIMILAR TO THOSE ON SUN.
OVERNIGHT THE UPR LOW WL MOVE INTO ERN UT AND MUCH OF THE FORECAST
AREA ENDS UP IN THE DRY SLOT...AS SHOW IN THE NAM12...THE NSSL WRF
AND THE GFS. THE CENTRAL MTS WL PROBABLY CONTINUE TO HAVE SOME PCPN
THRU THE NIGHT...BUT SHOULD GENERALLY BE LIGHT. WITH MOIST LOW LEVEL
UPSLOPE OVR THE ERN PLAINS TONIGHT...WIDESPREAD STRATUS IS EXPECTED.
THE ONLY AREA THAT ALL THE MODELS SHOW WIDESPREAD PCPN TONIGHT IS
OVR THE FAR SERN PLAINS...SO WL GO WITH LIKELY POPS IN THAT
AREA...WITH DECREASING POPS WESTWARD TO THE ERN MTS. THE NAM AND
GFS SHOW A FEW HUNDREDTHS OF PCPN OVR THE FAR ERN AREAS OVERNIGHT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 420 AM MDT MON APR 1 2013
TUESDAY AND WEDNESDAY...THE UPPER LOW PRES SYSTEM TRACKS FROM THE NW
TO THE SE DIRECTLY ACROSS COLORADO ON TUE AND WED...BRINGING A
DECENT SHOT AT SOME PCPN FOR THE FORECAST AREA. STARTING OUT TUE
MORNING...THE UPPER SYSTEM SHOULD BE PRODUCING SOME SHOWERS FOR THE
CENT MTS...WHILE LLVL EASTERLY UPSLOPE FLOW DUE TO SFC HI PRES OVER
NE AND KS WILL KEEP A SOLID THREAT OF PCPN FOR THE EASTERN PLAINS.
HOWEVER...AS THE UPPER LOW CONTINUES TO TRACK ACROSS THE
STATE...PCPN CHANCES SPREAD TO MUCH OF THE AREA BY TUE AFTN AND
REMAIN PROBABLE THROUGH THE NIGHT. ONGOING POP GRIDS LOOKED
REASONABLE FOR TUE NIGHT AND EARLY WED MORN WITH ONLY SLIGHT
ADJUSTMENTS NEEDED. THE TROUGH AXIS EXITS THE SE CORNER OF THE STATE
WED MID-MORNING...WITH PCPN THEN TAPERING OFF QUICKLY. AS FOR
TEMPS...MAX TEMPS IN THE 40S FOR TUE WILL GRADUALLY WARM INTO THE
50S FOR WED.
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT..THE REGION DRIES OUT AS AN
UPPER RIDGE OF HIGH PRESSURE MOVES ACROSS THE 4 CORNERS. TEMPS
SHOULD REMAIN COOL FOR WED...THEN REBOUND INTO THE MID TO UPPER 60S
FOR THU.
FRIDAY THROUGH SUNDAY...THE EXTENDED MODELS WANT TO KEEP THINGS A
BIT UNSETTLED OVER THE WEEKEND. ONE DISTURBANCE ROLLS ACROSS THE
ROCKIES ON FRIDAY BUT LOOKS LIKE IT WILL STAY MAINLY TO THE NORTH OF
THE STATE. A BRIEF BREAK ON SAT...THEN SAT NIGHT ANOTHER SHORTWAVE
TRACKS ACROSS THE GREAT BASIN AND DIGS FURTHER SOUTH...PROMISING A
BETTER SHOT AT SOME BENEFICIAL PCPN. FOR THE TIME BEING...KEPT
ISOLATED POPS OVER THE MTS OVER THE WEEKEND AS THE EXTENDED
PROCEDURE PRODUCED...AND WILL HAVE TO FINE TUNE AS THAT WINDOW
NEARS. FOR THE TIME BEING...FRIDAY LOOKS LIKE THE WARMEST DAY OF THE
EXTENDED FORECAST PERIOD. MOORE
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 420 AM MDT MON APR 1 2013
EXPECT VFR CONDITIONS TODAY AT KALS...KPUB AND KCOS. THERE COULD BE
A FEW LOW CLOUDS IN THE VCNTY OF KCOS THIS MORNING. EARLY THIS
EVENING THERE COULD BE A FEW SHOWERS AND MAYBE EVEN A THUNDERSTORMS
AT OR IN THE VCNTY OF KCOS...PROBABLY AFTER 22Z AND BEFORE 03Z.
KALS COULD ALSO SEE SOME SHOWERS OR A THUNDERSTORM IN THE
AREA...MAINLY AFTER 18Z AND BEFORE 01Z. KALS SHOULD HAVE VFR
CONDITIONS TONIGHT. KCOS AND KPUB SHOULD SEE LOW CLOUDS MOVE INTO
THE AREA AROUND 06Z WITH IFR CONDITIONS EXPECTED.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...28
LONG TERM...MOORE
AVIATION...28
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
340 AM MDT MON APR 1 2013
.SHORT TERM...AN UPPER LEVEL LOW WILL MOVE FROM NEVADA INTO UTAH
BY THIS EVENING. AHEAD OF THE LOW THE FLOW ALOFT WILL BE SWLY. AT
THE SURFACE HIGH PRES WILL BE OVER THE CNTRL PLAINS WITH LOW PRES
OVER WRN COLORADO. THIS WILL LEAD TO SELY LOW LVL FLOW OVER NERN
CO THRU TONIGHT. CROSS- SECTIONS SHOW AN INCREASE IN MOISTURE WITH
SOME MID LVL QG ASCENT MAINLY LATE TONIGHT. LAPSE RATES ARE BEST
OVER THE HIGHER TERRAIN WITH LESS INSTABILITY OVER THE PLAINS. AT
THIS TIME THE BEST CHC OF PCPN THRU THIS AFTN LOOKS TO BE IN THE
MTNS WITH DRY CONDITIONS OVER THE PLAINS. WILL MENTION SOME
THUNDER IN THE MTNS WHERE SOME CAPE EXISTS. HIGHS THIS AFTN OVER
NERN CO WILL RANGE FM THE UPPER 40S TO LOWER 50S EXCEPT POSSIBLY
ALONG THE FRONT RANGE WHERE SELY LOW LVL WINDS COMING OFF THE
PALMER DIVIDE COULD ALLOW FOR READINGS TO RISE INTO THE MID TO
UPPER 50S NR DENVER. THE RAP SHOWS HIGHS IN THE LOWER TO MID 60S
AROUND DENVER HOWEVER WILL NOT GO THIS WARM.
FOR TONIGHT SNOW SHOWERS WILL CONTINUE IN THE MTNS DUE TO INCREASING
QG ASCENT HOWEVER SWLY OROGRAPHIC FLOW MAY KEEP ACCUMULATIONS ON
THE LIGHT SIDE IN MOST AREAS. EAST OF THE MTNS THE LOW LVL FLOW
WILL REMAIN SELY. SHOULD SEE SOME SHOWERS DVLP IN THE FOOTHILLS BY
EARLY EVENING WITH SOME OF THE ACTIVITY SPREADING ACROSS THE
ADJACENT PLAINS OVERNIGHT. WITH SELY LOW LVL FLOW THE BEST CHC OF
PCPN MAY FOCUS IN THE NRN FOOTHILLS AND NORTH OF A DENVER TO LIMON
LINE. AT THIS TIME OVERALL CONFIDENCE IS NOT VERY HIGH AS TO WHERE
TO MENTION LIKELY POPS OVER THE PLAINS TONIGHT SO WILL KEEP POPS
IN THE CHC CATEGORY. SOUNDINGS SHOW WET BULB ZEROS WILL BECOME LOW
ENOUGH FOR SHOWERS TO MIX WITH OR CHANGE TO SOME SNOW AFTER
MIDNIGHT ACROSS THE PLAINS HOWEVER AT THIS TIME IT LOOKS LIKE ANY
ACCUMULATION WILL BE AN INCH OR LESS.
.LONG TERM...MODELS HAVE THE UPPER CLOSED LOW OVER EAST CENTRAL
UTAH...THEN OVER THE FOUR CORNERS AT 00Z TUESDAY AFTERNOON. BY 18Z
WEDNESDAY...ITS OVER SOUTHEASTERN/ WESTERN KANSAS. ON WEDNESDAY
NIGHT...INCREASING NORTHWESTERLY FLOW ALOFT IS PROGGED FOR THE
FORECAST AREA. THE QG VERTICAL VELOCITY FIELDS HAVE UPWARD MOTION
OVER THE CWA TUESDAY AND TUESDAY NIGHT ...HOWEVER IT IS NOT VERY
STRONG. WEAK DOWNWARD MOTION IS PROGGED WEDNESDAY AND WEDNESDAY
NIGHT. NORTHEAST TO SOUTHEASTERLY LOW LEVEL WINDS ARE PROGGED FOR
THE PLAINS AND FOOTHILLS TUESDAY AND TUESDAY EVENING. WEAK FLOW IS
PROGGED THE REST OF TUESDAY NIGHT THROUGH WEDNESDAY...WITH A
COMBINATION OF NORMAL DUIRNAL PATTERNS TO WEAK DOWNSLOPING
WEDNESDAY NIGHT. MOISTURE IS FAIRLY DEEP ON TUESDAY FOR MOST OF
THE CWA. IT IS PRETTY DEEP ON THE NAM TUESDAY NIGHT...DRIER ON THE
GFS. IT DRIES OUT SOMEWHAT ON WEDNESDAY. THERE IS SOME MOUNTAIN
MOISTURE WEDNESDAY NIGHT...BUT ITS DRIER ON THE PLAINS. MODELS
SHOW MINOR CAPE OVER THE MOUNTAINS AND FOOTHILLS LATE DAY TUESDAY
AND AGAIN WEDNESDAY AFTERNOON. THE QPF FIELDS SHOW MEASURABLE
PRECIPITATION TUESDAY AND TUESDAY EVENING FOR MOST AREAS...BEST
OVER THE FOOTHILLS AND EASTERN MOUNTIANS ZONES. THERE IS A TAD THE
REST OF TUESDAY NIGHT AND WEDNESDAY... MAINLY OVER THE MOUNTIANS.
FOR POPS...WILL KEEP THE "LIKELY"S IN OVER THE MOUNTAINS AND
"CHANCES" OUT ON THE PLAINS TUESDAY AND TUESDAY EVENING. THE
PLAINS WILL SEE BOTH SNOW AND RAIN...WITH LITTLE ACCUMULATION.
WILL DECREASE POPS THE REST OF TUESDAY NIGHT. ON WEDNESDAY...JUST
SOME MINOR ALPINE POPS. WILL PUT "ISOLATED" THUNDER IN BOTH
TUESDAY AND WEDNESDAY AFTERNOONS IN THE MOUNTIANS. FOR
TEMPERATURES...TUESDAY`S HIGHS ARE 2.0-3.5 C COOLER THAN TODAY`S
EXPECTED HIGHS. WEDNESDAY`S READINGS COME UP 3-7 C FROM TUESDAY`S.
FOR THE LATER DAYS...THURSDAY THROUGH SUNDAY...MODELS HAVE UPPER
RIDGING FOR COLORADO THROUGH MID DAY FRIDAY...THEN A WEAK UPPER
TROUGH IS PROGGED ACROSS THE STATE BY EARLY SATURDAY MORNING.
AFTER THAT...WEST-SOUTHWESTERLY FLOW ALOFT IS PROGGED OVER THE CWA
THROUGH SUNDAY. THERE IS LIMITED MOISTURE AROUND...BUT IT
INCREASES ON SUNDAY.
&&
.AVIATION...SO FAR ANY STRATUS WAS CONFINED TO THE FAR NERN CORNER
OF THE PLAINS SO AT THIS POINT IT DOES NOT APPEAR IT WILL AFFECT
THE AIRPORT THIS MORNING. AS FOR WINDS BOTH THE RAP AND HRR SHOW A
DENVER CYCLONE DEVELOPING SW OF DENVER WITH WINDS BEING E TO SE
THRU THE AFTN. COULD SEE SUSTAINED WINDS IN THE 15 TO 20 MPH BY
20Z. AT THIS TIME ANY CHC FOR RAIN SHOWERS WILL BE AFTER 00Z.
COULD SEE SHOWERS CHANGE TO SOME SNOW AFTER MIDNIGHT BUT ANY
ACCUMULATION WILL BE UNDER ONE HALF INCH AND CONFINED TO GRASSY
AREAS. LATEST NAM CONTINUES TO SHOW A CYCLONE OVERNIGHT OVER
DENVER WITH WINDS BECOMING MORE SLY AFTER MIDNIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM....RJK
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS MIAMI FL
1031 AM EDT MON APR 1 2013
.UPDATE...
THE MORNING SURFACE ANALYSIS SHOWED A HIGH PRESSURE RIDGE AXIS
EXTENDING WEST ACROSS SOUTH FLORIDA AND THE SOUTHEAST GULF OF
MEXICO AND A COLD FRONT APPROACHING FROM THE NORTH. SSW LOW-LEVEL
FLOW IS EXPECTED TO GRADUALLY VEER TOWARD THE WEST THROUGH THE
COURSE OF THE DAY AS THIS BOUNDARY CONTINUES SOUTH. THIS FLOW
COMBINED WITH THE AFTERNOON EAST COAST SEA BREEZE...A COUPLE OF
IMPULSES ALOFT AND MODERATE INSTABILITY AND SHEAR (0-6KM 30-35 KT)
COULD GENERATE A FEW STRONG TO EVEN SEVERE THUNDERSTORMS THROUGH
THE AFTERNOON/EVENING PERIOD TODAY OVER THE METRO/EAST COAST
LOCATIONS. THE LATEST WRF AND HRRR MODEL REFLECTIVITIES...
HOWEVER...ARE ONLY INDICATING ISOLATED COVERAGE OVER THESE AREAS
AT BEST THROUGH THIS TIME. ANY STORMS THAT DO INITIATE COULD BE
CAPABLE OF PRODUCING STRONG WINDS, HAIL AND POSSIBLY A TORNADO.
THE LATEST FORECAST HAS BEEN UPDATED TO REFLECT THIS POTENTIAL
THIS AFTERNOON. ELSEWHERE...VISIBILITIES HAVE BEGUN TO IMPROVE
OVER THE PAST HOUR ACROSS THE INTERIOR LOCATIONS FROM THE EARLY
MORNING FOG AND THIS TREND IS EXPECTED TO CONTINUE. THE LOCAL
OFFICIALS HAVE REPORTED THAT SEGMENTS OF I-75 HAVE BEEN CLOSED
TODAY DUE TO A COMBINATION OF THIS FOG EARLIER AND SMOKE FROM THE
ONGOING WILDFIRE IN COLLIER COUNTY.
&&
.PREV DISCUSSION... /ISSUED 739 AM EDT MON APR 1 2013/
AVIATION...
AN UPPER LEVEL SHORTWAVE ACROSS THE EASTERN GULF WILL MOVE ACROSS
THE FLORIDA PENINSULA TODAY. A FEW SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE MAINLY TO THE EAST OF THE EAST COAST TAF SITES THIS
MORNING. SEA BREEZE BOUNDARIES EARLY THIS AFTERNOON ARE EXPECTED TO
HELP GENERATE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS NEAR THE
EAST COAST TAF SITES. SO ADDED VCTS FOR THE EAST COAST TAFS. FOR
KAPF...THERE IS A SLIGHT CHANCE OF SHOWERS AHEAD OF THE
TROUGH...MAINLY BEFORE 18Z. WIND DIRECTION MAY VARY BETWEEN 160-210
DEGREES DURING THE DAY AT THE EAST COAST TAF SITES. WINDS WILL SHIFT
TO THE WEST TO NORTHWEST TONIGHT BEHIND THE BOUNDARY.
PREV DISCUSSION... /ISSUED 459 AM EDT MON APR 1 2013/
DISCUSSION...
CURRENTLY, A MID LEVEL TROUGH, ROUGHLY AT 700 MB, IS MOVING ACROSS
THE EASTERN GULF OF MEXICO. THIS HAS GENERATED A LINE OF
THUNDERSTORMS THAT IS EXPECTED TO FALL APART AS IT APPROACHES
CENTRAL FLORIDA. THIS TROUGH, ACCORDING TO THE HRRR, MAY SPARK OFF
A FEW SHOWERS OVER SOUTH FLORIDA THIS MORNING. ALSO, ANOTHER SHORT
WAVE HAS GENERATED SOME SHOWERS AND ISOLATED THUNDERSTORMS OVER
THE FLORIDA STRAITS. THESE ARE MOVING NORTH NORTHEAST. THE SHOWERS
WILL AFFECT THE SOUTHEASTERN PORTION OF THE CWA THIS MORNING. THE
QUESTION IS IF THERE WILL BE ANY THUNDERSTORMS THAT MOVE INTO THE
AREA AS WELL. THERE IS AROUND 1000 JOULES JUST ONSHORE, AROUND
HOMESTEAD AND MIAMI. SO, ALTHOUGH ORIGINAL THINKING WAS THEY WOULD
STAY OFFSHORE, MAY HAVE TO ADD A MENTION OF THUNDERSTORMS FOR THIS
AREA THIS MORNING.
AS FOR LATER TODAY, MODELS INDICATE THE TROUGH, OR REALLY, A
WEAKENING FRONT, WILL MOVE ONSHORE THE GULF COAST LATER THIS
MORNING. MODELS ARE INDICATING IT WILL NOT BE TOO ACTIVE,
CONVECTION WISE WHEN IT DOES. BUT, AS IT PROGRESS ACROSS THE
STATE, ALONG WITH DAYTIME HEATING, CONVECTION MAY BE ABLE TO
INITIATE. THE MODELS DO DIFFER GREATLY WITH HOW MUCH CAPE WILL BE
AVAILABLE. THE GFS KEEPS THE HIGHEST BOUNDARY LAYER CAPE VALUES
WELL OFFSHORE AND ONLY 500-600 JOULES OVER THE ATLANTIC COAST. THE
NAM, ON THE OTHER HAND, HAS 1200 TO 1600 JOULES OVER THE ATLANTIC
COAST, NEAT WEST PALM BEACH, AND DROPS TO 500-700 JOULES NEAR
MIAMI. NOW THE NAM MODEL SOUNDINGS HAVE 1200-1600 JOULES ALL OVER
THE ATLANTIC COAST. THEY DO SHOW A WEAK CAP FURTHER NORTH, BUT IT
IS SO WEAK, NOT THINKING IT WILL BE A REAL INHIBITOR. THERE IS
ALSO A TOUCH OF CIN TO THE NORTH AS WELL, BUT AGAIN, NOTHING THAT
REALLY SHOULD INHIBIT DEVELOPMENT. SO, WHAT WILL INHIBIT THEIR
DEVELOPMENT. WELL, MODELS DO SHOW THAT THE CAPE WILL BE PUSHING
OFF TO THE EAST, AHEAD OF THE TROUGH. SO, WE MAY BE LACKING THE
LIFTING MECHANISM. IT MAY ARRIVE WELL AFTER THE CAPE HAS PUSHED
OFF SHORE. SO, HAVE KEPT CHC POPS AND SLIGHT CHC TSTMS, BUT HAVE
BROADENED THE COVERAGE OF TSTMS THIS AFTERNOON.
BEHIND THE TROUGH TODAY, HIGH PRESSURE WILL BE BUILDING IN FAIRLY
QUICK. THIS WILL BRING QUIET WEATHER BACK TO SOUTH FLORIDA FOR A
FEW DAYS.
FOR FRIDAY AND THE WEEKEND, A LOW PRESSURE SYSTEM WILL DEVELOP
OVER THE WESTERN GULF AND MOVE OVER THE FLORIDA PANHANDLE THURSDAY
NIGHT/FRIDAY MORNING. A COLD FRONT WILL MOVE THROUGH SOUTH FLORIDA
FRIDAY. THIS SYSTEM WILL BRING OUR NEXT CHANCE FOR RAIN AND
POSSIBLY A THUNDERSTORM. MODELS ARE IN PRETTY GOOD AGREEMENT WITH
THE STRENGTH, POSITION, AND TIMING OF THIS SYSTEM. GIVEN THIS,
HAVE A HIGH CHC POP IN THE FORECAST FOR FRIDAY. BEHIND THE FRONT,
HIGH PRESSURE WILL BUILD IN ONCE AGAIN. TEMPERATURES WILL NOT BE
MUCH COOLER, ONLY A FEW DEGREES. THIS HIGH PRESSURE WILL LAST FOR
THE REMAINDER OF THE EXTENDED FORECAST.
MARINE...
WINDS AHEAD OF A WEAK FRONT/TROUGH WILL PICK UP OUT OF THE SOUTH
TO BETWEEN 13 AND 19 KTS OVER THE ATLANTIC WATERS. THEY SHOULD
REMAIN BELOW 10 KTS OVER THE GULF WATERS. THE HIGHER WIND SPEEDS
OVER THE ATLANTIC WATERS HAS PROMPTED A SMALL CRAFT SHOULD
EXERCISE CAUTION STATEMENT FOR THIS AFTERNOON. SEAS TODAY WILL BE
SUBSIDING SOMEWHAT, EVEN WITH THE WINDS, AND ARE EXPECTED TO BE 1
TO 3 FEET BY TOMORROW IN THE ATLANTIC WATERS. THE GULF WATERS WILL
BE AROUND 1 FOOT FOR THE NEXT COUPLE OF DAYS. HIGH PRESSURE WILL
BUILD IN BEGINNING TONIGHT. THIS WILL CAUSE WINDS TO WEAKEN SOME
TONIGHT TO 7-10 KTS OVER THE ATLANTIC AND SHIFT THEM OUT OF THE
NORTH TOMORROW.
FIRE WEATHER...
THE MAIN FIRE WEATHER CONCERN TODAY ARE THE SHIFTING WINDS. AN
APPROACHING FRONT/TROUGH WILL CAUSE WINDS TO PICK UP SOME TODAY TO
10 TO 15 MPH OVER GLADES, HENDRY, AND INTERIOR COLLIER COUNTIES.
THEY WILL BEGIN OUT OF THE SOUTHEAST, BUT TURN THROUGH THE DAY TO
THE SOUTH, THEN SOUTHWEST BY EARLY AFTERNOON. BY THIS EVENING,
THEY WILL BECOME WESTERLY BETWEEN 5 AND 10 MPH. ALONG WITH THIS
WIND SHIFT, WILL BE THE CHANCE FOR SOME RAIN SHOWERS AND A SLIGHT
CHANCE FOR A THUNDERSTORM. THE CHANCES INCREASE AS YOU GO EASTWARD
ACROSS SOUTH FLORIDA. IN THE INTERIOR PORTION OF THE AREA, THE
DIVIDING LINE FOR THE CHANCE OF AND THUNDERSTORMS IS A DIFFICULT
ONE AT BEST. SO, AREAS WEST OF THE FORECASTED AREA, SHOULD REMAIN
AWARE OF THE POSSIBILITY THAT THE FORECAST COULD CHANGE TO INCLUDE
THEM AS THE TROUGH GETS CLOSER. ONE THE OTHER HAND, IT COULD ALSO
BE PUSHED FURTHER EAST. THERE IS JUST GREAT UNCERTAINTY WITH THE
CONVECTIVE DEVELOPMENT TODAY.
BEHIND THE TROUGH, HIGH PRESSURE WILL BUILD IN THROUGH THURSDAY,
BRINGING QUIET WEATHER BACK TO SOUTH FLORIDA.
PREV DISCUSSION... /ISSUED 241 AM EDT MON APR 1 2013/
AVIATION...
ISOLATED SHOWERS WERE MOVING ACROSS THE ATLANTIC WATERS AND NEAR
KFLL AND FXE. ANOTHER AREA OF SHOWERS AND EMBEDDED THUNDERSTORMS
WERE MOVING JUST SOUTH OF THE KEYS. THIS AREA OF SHOWERS AND
STORMS WILL CONTINUE TO MOVE NORTHWARD OVERNIGHT...AND COULD GET
NEAR KTMB AND KMIA IN THE NEXT FEW HOURS IF THEY HOLD TOGETHER. A
SHORTWAVE TROUGH MOVING ACROSS THE EASTERN GULF WAS FORCING
SHOWERS AND THUNDERSTORMS TO DEVELOP WEST OF TAMPA. THE HRRR
KEEPS THIS LINE TOGETHER AND MOVES IT TOWARDS KAPF AROUND 16Z.
OTHER SHOWERS OR STORMS COULD ALSO BEGIN DEVELOPING ON THE EAST
COAST SEA BREEZE AROUND THIS TIME. THE WIND DIRECTION IS ALSO
TRICKY TODAY AS THE BOUNDARY LAYER WINDS SHIFT TO THE SOUTHWEST
AHEAD OF THE TROUGH AND WEAK COLD FRONT. SO THE WINDS MAY SHIFT TO
THE SOUTHWEST FOR A TIME LATE IN THE MORNING BEFORE THE EAST COAST
SEA BREEZE BOUNDARY TRIES TO PUSH THE WINDS BACK TO THE SOUTH OR
SOUTHEAST. BY 00Z...SOUTHWESTERLY FLOW IS EXPECTED TO
PREVAIL...WITH WEST TO NORTHWESTERLY FLOW BEHIND THE SURFACE
TROUGH AFTER 02-04Z. SO FOR THE TAFS...KEPT VCSH FOR NOW...BUT
MAY NEED TO ADD VCTS. MVFR CONDITIONS ARE POSSIBLE NEAR ANY
SHOWERS OR STORMS THAT FORM.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 65 81 68 / 50 20 10 -
FORT LAUDERDALE 82 66 82 69 / 50 20 10 -
MIAMI 82 67 83 69 / 50 20 10 -
NAPLES 79 63 79 63 / 20 10 10 -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
635 AM EDT MON APR 1 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 353 AM EDT MON APR 1 2013
A WEAK UPPER WAVE WILL MOVE THROUGH THE AREA THIS MORNING BUT HIGH
PRESSURE WILL BUILD IN THIS AFTERNOON AND KEEP DRY WEATHER ACROSS
THE AREA THROUGH SATURDAY. SATURDAY NIGHT A LOW PRESSURE SYSTEM WILL
APPROACH AND BRING CHANCES FOR RAIN. TEMPERATURES WILL BE WELL BELOW
NORMAL TODAY THROUGH TUESDAY NIGHT AND THEN REBOUND TO ABOVE NORMAL
BY THE WEEKEND.
&&
.NEAR TERM /TODAY/...
ISSUED AT 353 AM EDT MON APR 1 2013
FORECAST FOCUS IS ON NEED FOR ANY POPS FROM EARLY TO MID MORNING.
UPPER WAVE IS CURRENTLY MOVING SOUTHEAST THROUGH SOUTHERN IOWA AND
WESTERN ILLINOIS. RADAR MOSAIC SHOWS WEAK ECHOES OVER WESTERN AND
CENTRAL ILLINOIS AS WELL AS SOME ENTERING WESTERN INDIANA BUT
SURFACE OBS SHOW NO PRECIP AT THE GROUND. GFS AND NAM ARE BOTH DRY
AND GUIDANCE IS AS WELL. RAPID REFRESH AND RAP SHOW SOME DEVELOPMENT
OCCURRING ACROSS THE SOUTHERN COUNTIES AROUND 11-12Z AND MOVING
THROUGH BY 15Z. WITH BOTH OF THE RAPID UPDATE MODELS SHOWING THIS
DEVELOPMENT WILL GO AHEAD AND LEAVE A SLIGHT CHANCE FOR RAIN AND
SNOW MOVING ACROSS THE SOUTH FROM 11 TO 15Z AND DRY FROM 15Z ON.
SHOULD NOT AMOUNT TO ANYTHING. WILL DROP ANY MENTION OF FLURRIES
ELSEWHERE.
CLOUDS SHOULD SCATTER OUT AS THE DAY GOES ON. WILL SEE COLD
ADVECTION THROUGHOUT THE DAY SO TEMPERATURES SHOULD STRUGGLE TO WARM
AND THUS WENT WITH A CONSENSUS OF RAW MODEL NUMBERS SINCE
CLIMATOLOGY COULD BIAS THINGS UP.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 353 AM EDT MON APR 1 2013
HIGH PRESSURE WILL DOMINATE THE WEATHER IN THE SHORT TERM. MODELS
ARE IN GOOD AGREEMENT AND WILL USE A CONSENSUS. WITH MOSTLY CLEAR TO
CLEAR SKIES THROUGHOUT THE SHORT TERM STUCK CLOSE TO COOLER GUIDANCE
NUMBERS AT NIGHT OF LOW TO MIDDLE 20S. FOR HIGHS TUESDAY AGAIN THOUGHT
GUIDANCE WAS BIASED A BIT WARM FROM CLIMATOLOGY SO STUCK WITH A RAW
MODEL CONSENSUS IN THE LOW TO MID 40S...BUT BY WEDNESDAY THE AIR
MASS SHOULD BE REBOUNDING UNDER WARM ADVECTION AND A COMPLETE
CONSENSUS LOOKED GOOD IN THE UPPER 40S TO LOW 50S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ISSUED AT 324 AM EDT MON APR 1 2013
A LARGE AREA OF HIGH PRESSURE WILL BE MOVING AWAY TO THE EAST ON
THURSDAY WITH A SPLIT FLOW PATTERN ALOFT AS A WEAK FRONT
APPROACHES FROM THE NORTHWEST AND AN UPPER LOW TRACKS ACROSS THE
SOUTHERN PLAINS. MODEL CONSENSUS HAS BEEN TRACKING THE UPPER WAVE
FURTHER NORTH OVER THE LAST COUPLE DAYS AND BRINGS THE NORTHERN
FRINGES OF THE RAINFALL ASSOCIATED WITH THE UPPER LOW INTO THE
OHIO RIVER VALLEY THURSDAY NIGHT. CONSIDERING THE NORTHERLY LOW
LEVEL FLOW...PRESENCE OF DRIER AIR OVER THE REGION AND THE BULK OF
THE DEEPER FORCING REMAINING TO THE SOUTH OF THE FORECAST
AREA...WILL CONTINUE TO KEEP A DRY FORECAST GOING THURSDAY NIGHT.
DO ANTICIPATE AN INCREASE IN CLOUDS OVER THE SOUTHERN COUNTIES
THURSDAY NIGHT AND EARLY FRIDAY AS THE UPPER WAVE PASSES TO THE
SOUTH. THE AFOREMENTIONED WEAK FRONT APPROACHING FROM THE
NORTHWEST SET TO WASH OUT ACROSS THE LOWER GREAT LAKES THURSDAY
NIGHT.
AS THE UPPER WAVE WEAKENS AND SHIFTS INTO THE SOUTHEAST STATES BY
FRIDAY AFTERNOON...HIGH PRESSURE WILL REESTABLISH ACROSS THE OHIO
VALLEY WITH AN EXPANSION OF RIDGING ALOFT BRINGING WARMER AIR INTO
THE REGION. LOW LEVEL THERMALS SUPPORT HIGH TEMPS RISING INTO THE 60S
BY SATURDAY. FORECAST MORE MUDDLED FOR THE SECOND HALF OF THE
WEEKEND AS A DEVELOPING WARM FRONT SETS UP OVER THE LOWER GREAT
LAKES AND A SURFACE WAVE TRACKS ALONG THE BOUNDARY ON SUNDAY. WILL
CARRY LOW CHANCE POPS SATURDAY NIGHT INTO SUNDAY AS THE SURFACE
WAVE PASSES THROUGH THE AREA. APPEARS THE BOUNDARY MAY SETTLE
FURTHER SOUTH NEAR THE OHIO RIVER BY LATE SUNDAY WITH THE PASSAGE
OF THE LOW...BEFORE THE BOUNDARY RETURNS BACK NORTH EARLY NEXT
WEEK. LOW LEVEL THERMALS STILL SUGGESTIVE OF HIGHS IN THE 60S FOR
SUNDAY EVEN AS THE BOUNDARY SHIFTS SOUTH...WITH POSSIBILITY FOR
WARMER DAYTIME HIGHS EARLY NEXT WEEK ONCE THE FRONT LIFTS BACK
NORTH.
&&
.AVIATION /DISCUSSION FOR 011200Z TAF ISSUANCE/...
ISSUED AT 635 AM EDT MON APR 1 2013
VFR CONDITIONS ANTICIPATED THROUGHOUT THE FORECAST PERIOD.
MID LEVEL CLOUDS PRESENT EARLY THIS MORNING AS AN UPPER WAVE
MOVES THROUGH THE REGION. AREA OF RETURNS NOTED FROM WESTERN
INDIANA BACK INTO ILLINOIS BUT APPEARS LITTLE IF ANY OF THIS IS
REACHING THE GROUND BASED ON CURRENT OBS. MAY SEE A FEW FLURRIES
AT KBMG/KHUF/KIND THROUGH 15Z BUT EXPECT NO IMPACTS TO TERMINALS.
MODEL SOUNDINGS SHOW FAVORABLE CONDITIONS FOR CU DEVELOPMENT THIS
AFTERNOON WITH CONVECTIVE TEMPS IN THE UPPER 30S AND INCREASING COLD
ADVECTION. LIKELY TO SEE GUSTS TO AROUND 20KTS AS WELL THROUGH THE
AFTERNOON WITH GOOD LOW LEVEL MIXING.
AS HIGH PRESSURE SPREADS INCREASINGLY DRIER AIR INTO THE FORECAST
AREA...WILL SEE A GRADUAL DECREASE IN CU BY LATE DAY WITH SKIES
BECOMING MOSTLY CLEAR TONIGHT.NORTHWEST WINDS WILL BECOME LIGHT
THIS EVENING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....RYAN
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS WICHITA KS
1013 AM CDT MON APR 1 2013
.UPDATE...
ISSUED AT 1013 AM CDT MON APR 1 2013
SENT OUT A QUICK UPDATE TO KEEP UP WITH CURRENT PRECIP TRENDS.
ISENTROPIC LIFT ALONG THE 305K SURFACE HAS RESULTED IN PRECIP
EXPANDING OVER SW PORTIONS OF THE FORECAST AREA. THIS ACTIVITY
SHOULD CONTINUE TO PUSH EAST LATE THIS MORNING INTO THE EARLY
AFTERNOON HOURS. A COUPLE RUMBLES OF THUNDER MAY MIX WITH THE
SHOWERS.
LAWSON
&&
.SYNOPSIS...
ISSUED AT 332 AM CDT MON APR 1 2013
A POTENT DISTURBANCE IS PLUNGING SOUTHWARD INTO THE GREAT LAKES
REGION...CAUSING A COLD FRONT TO DIVE SOUTHWARD ACROSS THE CENTRAL
PLAINS. THE COLD FRONT HAS MADE IT HALF WAY THROUGH KANSAS AS OF
THIS ISSUANCE AND WILL CONTINUE TO MOVE SOUTHWARD THROUGH OKLAHOMA
DURING THE DAY. WINDS ARE GUSTY BEHIND THE FRONT WITH LOW TO MID
LEVEL CLOUDS. LOOKING WEST...ANOTHER DISTURBANCE IS LOCATED OVER
MID-CALIFORNIA/NEVADA/UTAH. THIS WILL BE THE WEATHER MAKER FOR THE
FIRST PART OF THE WEEK.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 332 AM CDT MON APR 1 2013
THIS PERIOD WILL BE RAINY OFF AND ON AND COOLER FOR MUCH OF SOUTHERN
KANSAS. THE LATEST GUIDANCE...NAM/GFS/ECMWF AND HRRR INDICATE
PRECIPITATION DEVELOPING ACROSS SOUTH CENTRAL KANSAS AROUND MID
AFTERNOON TODAY BEFORE SPREADING EAST ACROSS SOUTHERN KANSAS THROUGH
THE DAY AND OVERNIGHT. PRECIPITATION WILL DEVELOP NEAR THE 850MB
FRONT. THE UPPER LEVEL WAVE OVER THE WEST WILL CONTINUE TO MOVE
TOWARDS THE AREA...ENHANCING UPPER LEVEL SUPPORT. THE 850MB FRONT
WILL REMAIN STATIONARY...KEEPING THE PRECIPITATION CHANCES THROUGH
WEDNESDAY. NOT EXPECTING THUNDER WITH THIS EVENT WITH VERY LOW
MUCAPE VALUES...BUT CANNOT RULE OUT AN ISOLATED LIGHTNING STRIKE.
THIS PERIOD WILL REMAIN COOLER...AS THE COLD FRONT USHERED IN
UNSEASONABLY COOL AIR. WITH COLD AIR ADVECTION...CLOUDY SKIES AND
RAIN...TEMPERATURES WILL BE 10 TO 20 DEGREES BELOW NORMAL. TUESDAY
LOOKS TO BE THE COOLEST DAY WITH CLOUD COVER AND RAIN.
BILLINGS
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 332 AM CDT MON APR 1 2013
BY THURSDAY THE UPPER LEVEL DISTURBANCE THAT WILL IMPACT THE AREA
FOR THE FIRST HALF OF THE FORECAST WILL FINALLY BE ON ITS WAY EAST.
SURFACE HIGH PRESSURE WILL MOVE OVERHEAD THURSDAY WITH CLEARING
SKIES IN THE SUBSIDENCE ZONE OF THE UPPER WAVE. THIS WILL ALLOW
TEMPERATURES TO WARM BACK INTO THE UPPER 50S AND LOW 60S.
TEMPERATURES WILL CONTINUE TO INCREASE FOR FRIDAY AND SATURDAY AHEAD
OF THE NEXT SYSTEM. LEE CYCLOGENESIS WILL DEEPEN AHEAD OF THE NEXT
WAVE...WITH STRONG WARM AIR ADVECTION AND MIXING...TEMPS WILL REACH
BACK INTO THE 60S AND 70S. THE NEXT DISTURBANCE WILL MOVE ACROSS
THE NORTHERN PLAINS...DRAGGING A COLD FRONT ACROSS THE REGION. THE
MAIN LIFT ASSOCIATED WITH THIS FRONT WILL BE ACROSS THE NORTHERN
PLAINS...SO NOT EXPECTING MUCH IN THE WAY OF PRECIPITATION ALONG THE
FRONTAL BOUNDARY AND HAVE LEFT THE FORECAST DRY FOR SATURDAY AND
SUNDAY. TEMPERATURES BEHIND THE FRONT WILL ONLY DECREASE SLIGHTLY.
ANOTHER WAVE WILL APPROACH FOR THE VERY END OF THE FORECAST AND
PRECIPITATION MAY RETURN FOR SUNDAY AND INTO THE EARLY PART OF NEXT
WEEK. WILL CONTINUE TO WATCH THIS PERIOD AS THE FORECAST EVOLVES AS
THE TIME PERIOD NEARS.
BILLINGS
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 648 AM CDT MON APR 1 2013
A SHARP COLD FRONT HAS ALREADY MOVED ACROSS MOST LOCATIONS THIS
MORNING EXPECT SOME GUSTY WINDS TO 25 KTS FOR A FEW HOURS AFTER THE
FRONT MOVES THROUGH. WILL ALSO SEE SOME POST FRONTAL MVFR CEILINGS
ALSO DROP SOUTH ACROSS THE REGION FOR A FEW HOURS AFTER THE FRONT
PASSES...WITH CEILINGS OF 1500 FT AGL. EXPECT THIS MVFR CLOUD DECK
TO BE SHORT LIVED....WITH LOWER CLOUDS STAYING AROUND FOR ONLY 4 OR
5 HOURS. LIFT OVER THE TOP OF THE SHALLOW COLD AIR ACROSS SRN
KS...WILL LEAD TO A CHANCE OF SOME LIGHT RAIN SHOWERS FOR MAINLY SRN
KS. SO WILL INCLUDE A VCSH FOR THE KICT/KHUT AND KCNU TAF SITES
AFTER 22Z/MON. WILL SEE MORE OF WIDESPREAD LIGHT RAIN CHANCE DEVELOP
LATE TNGT INTO TUE AM...AFTER 12Z TUE. COULD ALSO SEE CEILINGS DROP
TO LOW MVFR OR POSSIBLY IFR ACROSS SRN KS ON TUE....BUT THIS IS
BEYOND THIS TAF TIME FRAME.
KETCHAM
&&
.FIRE WEATHER...
ISSUED AT 332 AM CDT MON APR 1 2013
VERY LITTLE IN THE WAY OF FIRE CONCERN FOR MUCH OF THE FORECAST.
LIGHT WINDS AND PRECIPITATION WILL KEEP GRASSLAND FIRE DANGER LOW.
WITH STRONGER WINDS AND WARMER TEMPERATURES ON FRIDAY...GRASSLAND
FIRE DANGER WILL BE VERY HIGH.
BILLINGS
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 51 35 43 35 / 40 60 50 30
HUTCHINSON 50 33 45 32 / 30 40 40 20
NEWTON 51 32 43 31 / 20 30 30 20
ELDORADO 51 33 44 33 / 30 40 40 20
WINFIELD-KWLD 53 36 42 36 / 40 70 70 40
RUSSELL 51 30 48 30 / 10 30 20 10
GREAT BEND 50 31 46 31 / 20 30 30 20
SALINA 52 31 50 33 / 10 20 10 10
MCPHERSON 51 32 46 32 / 20 30 20 10
COFFEYVILLE 55 37 44 36 / 30 60 70 40
CHANUTE 53 34 44 34 / 20 30 30 10
IOLA 52 33 45 33 / 20 20 20 10
PARSONS-KPPF 53 35 44 35 / 30 50 50 30
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
651 AM CDT MON APR 1 2013
.SYNOPSIS...
ISSUED AT 332 AM CDT MON APR 1 2013
A POTENT DISTURBANCE IS PLUNGING SOUTHWARD INTO THE GREAT LAKES
REGION...CAUSING A COLD FRONT TO DIVE SOUTHWARD ACROSS THE CENTRAL
PLAINS. THE COLD FRONT HAS MADE IT HALF WAY THROUGH KANSAS AS OF
THIS ISSUANCE AND WILL CONTINUE TO MOVE SOUTHWARD THROUGH OKLAHOMA
DURING THE DAY. WINDS ARE GUSTY BEHIND THE FRONT WITH LOW TO MID
LEVEL CLOUDS. LOOKING WEST...ANOTHER DISTURBANCE IS LOCATED OVER
MID-CALIFORNIA/NEVADA/UTAH. THIS WILL BE THE WEATHER MAKER FOR THE
FIRST PART OF THE WEEK.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 332 AM CDT MON APR 1 2013
THIS PERIOD WILL BE RAINY OFF AND ON AND COOLER FOR MUCH OF SOUTHERN
KANSAS. THE LATEST GUIDANCE...NAM/GFS/ECMWF AND HRRR INDICATE
PRECIPITATION DEVELOPING ACROSS SOUTH CENTRAL KANSAS AROUND MID
AFTERNOON TODAY BEFORE SPREADING EAST ACROSS SOUTHERN KANSAS THROUGH
THE DAY AND OVERNIGHT. PRECIPITATION WILL DEVELOP NEAR THE 850MB
FRONT. THE UPPER LEVEL WAVE OVER THE WEST WILL CONTINUE TO MOVE
TOWARDS THE AREA...ENHANCING UPPER LEVEL SUPPORT. THE 850MB FRONT
WILL REMAIN STATIONARY...KEEPING THE PRECIPITATION CHANCES THROUGH
WEDNESDAY. NOT EXPECTING THUNDER WITH THIS EVENT WITH VERY LOW
MUCAPE VALUES...BUT CANNOT RULE OUT AN ISOLATED LIGHTNING STRIKE.
THIS PERIOD WILL REMAIN COOLER...AS THE COLD FRONT USHERED IN
UNSEASONABLY COOL AIR. WITH COLD AIR ADVECTION...CLOUDY SKIES AND
RAIN...TEMPERATURES WILL BE 10 TO 20 DEGREES BELOW NORMAL. TUESDAY
LOOKS TO BE THE COOLEST DAY WITH CLOUD COVER AND RAIN.
BILLINGS
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 332 AM CDT MON APR 1 2013
BY THURSDAY THE UPPER LEVEL DISTURBANCE THAT WILL IMPACT THE AREA
FOR THE FIRST HALF OF THE FORECAST WILL FINALLY BE ON ITS WAY EAST.
SURFACE HIGH PRESSURE WILL MOVE OVERHEAD THURSDAY WITH CLEARING
SKIES IN THE SUBSIDENCE ZONE OF THE UPPER WAVE. THIS WILL ALLOW
TEMPERATURES TO WARM BACK INTO THE UPPER 50S AND LOW 60S.
TEMPERATURES WILL CONTINUE TO INCREASE FOR FRIDAY AND SATURDAY AHEAD
OF THE NEXT SYSTEM. LEE CYCLOGENESIS WILL DEEPEN AHEAD OF THE NEXT
WAVE...WITH STRONG WARM AIR ADVECTION AND MIXING...TEMPS WILL REACH
BACK INTO THE 60S AND 70S. THE NEXT DISTURBANCE WILL MOVE ACROSS
THE NORTHERN PLAINS...DRAGGING A COLD FRONT ACROSS THE REGION. THE
MAIN LIFT ASSOCIATED WITH THIS FRONT WILL BE ACROSS THE NORTHERN
PLAINS...SO NOT EXPECTING MUCH IN THE WAY OF PRECIPITATION ALONG THE
FRONTAL BOUNDARY AND HAVE LEFT THE FORECAST DRY FOR SATURDAY AND
SUNDAY. TEMPERATURES BEHIND THE FRONT WILL ONLY DECREASE SLIGHTLY.
ANOTHER WAVE WILL APPROACH FOR THE VERY END OF THE FORECAST AND
PRECIPITATION MAY RETURN FOR SUNDAY AND INTO THE EARLY PART OF NEXT
WEEK. WILL CONTINUE TO WATCH THIS PERIOD AS THE FORECAST EVOLVES AS
THE TIME PERIOD NEARS.
BILLINGS
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 648 AM CDT MON APR 1 2013
A SHARP COLD FRONT HAS ALREADY MOVED ACROSS MOST LOCATIONS THIS
MORNING EXPECT SOME GUSTY WINDS TO 25 KTS FOR A FEW HOURS AFTER THE
FRONT MOVES THROUGH. WILL ALSO SEE SOME POST FRONTAL MVFR CEILINGS
ALSO DROP SOUTH ACROSS THE REGION FOR A FEW HOURS AFTER THE FRONT
PASSES...WITH CEILINGS OF 1500 FT AGL. EXPECT THIS MVFR CLOUD DECK
TO BE SHORT LIVED....WITH LOWER CLOUDS STAYING AROUND FOR ONLY 4 OR
5 HOURS. LIFT OVER THE TOP OF THE SHALLOW COLD AIR ACROSS SRN
KS...WILL LEAD TO A CHANCE OF SOME LIGHT RAIN SHOWERS FOR MAINLY SRN
KS. SO WILL INCLUDE A VCSH FOR THE KICT/KHUT AND KCNU TAF SITES
AFTER 22Z/MON. WILL SEE MORE OF WIDESPREAD LIGHT RAIN CHANCE DEVELOP
LATE TNGT INTO TUE AM...AFTER 12Z TUE. COULD ALSO SEE CEILINGS DROP
TO LOW MVFR OR POSSIBLY IFR ACROSS SRN KS ON TUE....BUT THIS IS
BEYOND THIS TAF TIME FRAME.
KETCHAM
&&
.FIRE WEATHER...
ISSUED AT 332 AM CDT MON APR 1 2013
VERY LITTLE IN THE WAY OF FIRE CONCERN FOR MUCH OF THE FORECAST.
LIGHT WINDS AND PRECIPITATION WILL KEEP GRASSLAND FIRE DANGER LOW.
WITH STRONGER WINDS AND WARMER TEMPERATURES ON FRIDAY...GRASSLAND
FIRE DANGER WILL BE VERY HIGH.
BILLINGS
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 51 35 43 35 / 40 60 50 30
HUTCHINSON 50 33 45 32 / 30 40 40 20
NEWTON 51 32 43 31 / 30 30 30 20
ELDORADO 51 33 44 33 / 30 40 40 20
WINFIELD-KWLD 53 36 42 36 / 40 70 70 40
RUSSELL 51 30 48 30 / 20 30 20 10
GREAT BEND 50 31 46 31 / 20 30 30 20
SALINA 52 31 50 33 / 20 20 10 10
MCPHERSON 51 32 46 32 / 30 30 20 10
COFFEYVILLE 55 37 44 36 / 40 60 70 40
CHANUTE 53 34 44 34 / 30 30 30 10
IOLA 52 33 45 33 / 30 20 20 10
PARSONS-KPPF 53 35 44 35 / 30 50 50 30
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
927 AM EDT MON APR 1 2013
.SYNOPSIS...
NORTHWEST WINDS WILL PROVIDE BELOW NORMAL TEMPERATURES THROUGH
MIDWEEK. AN UPPER LEVEL SYSTEM WILL BRING THE RISK FOR RAIN OR
SNOW SHOWERS TODAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A MIX OF RAIN AND SNOW SHOWERS CONTINUE TO CROSS THE REGION ALONG
AND BEHIND THE COLD FRONT THIS MORNING. HAVE BUMPED UP THE POPS
ACCORDINGLY USING RUC DATA THAT SEEMS TO BE HANDLING THE TIMING
AND SCATTERED NATURE OF THE SHOWERS QUITE WELL. TEMPERATURES AHEAD
OF THIS BOUNDARY HAVE WARMED UP SLIGHTLY BUT THIS WILL BE BRIEF AS
COLD ADVECTION SHOULD GENERALLY KEEP A DOWNWARD TREND IN TEMPS
DURING THE DAY.
LATEST MODEL SOUNDINGS ARE SHOWING A DRY AIR MASS SETTLING IN THE
LOWER LEVELS THIS AFTERNOON. THIS WILL LIMIT LAKE EFFECT /UP-SLOPE
SNOW SHOWER DEVELOPMENT. THE HIGHEST RIDGES WILL HAVE THE BEST
CHANCE TO SEE MORE NUMEROUS SNOW SHOWERS AS ELEVATION WILL KEEP
THEM IN A THE SATURATED LAYER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
OUR BRIEF ACQUAINTANCE WITH SPRING WILL SADLY DEPART AS WE ONCE
AGAIN RETURN TO A PATTERN MORE REMINISCENT OF WINTER WITH THE
EASTERN HALF OF THE CONUS UNDER THE INFLUENCE OF A LARGE UPPER
LEVEL TROUGH THROUGH MUCH OF THE PERIOD. WHILE THE UPPER LEVEL
FLOW MAY KEEP A SLIGHTLY MORE WESTERLY THAN NORTHWESTERLY
COMPONENT...SHORTWAVES DIVING THROUGH THE COLD UPPER LEVEL FLOW
SHOULD PROVIDE AT LEAST CLOUD COVER THROUGH LATE TUESDAY AND SOME
LAKE ENHANCED SNOW SHOWERS POSSIBLE IMMEDIATELY DOWNWIND OF LAKE
ERIE...THOUGH IT IS QUESTIONABLE TO WHETHER IT WILL REALLY IMPACT
OUR NORTHERN ZONES VERY MUCH.
BY WEDNESDAY...MODELS SHOW A FEW INCONSISTENCIES IN THE PLACEMENT
AND STRENGTH OF A SHORTWAVE DIVING THROUGH THE TROUGH AND ITS
IMPACT TO THE REGION. AS SUCH...OPTED TO REMAIN CLOSER TO THE
ENSEMBLE MEANS WHICH KEEP THE REGION DRY. EVEN FOR THE START OF
APRIL....COLD ADVECTION AND CLOUD COVER SHOULD KEEP TEMPERATURES
BELOW SEASONAL AVERAGES THROUGH THE PERIOD.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MODEL AND ENSEMBLE SOLUTIONS ALL FAVOR A DRY EXTENDED FORECAST WITH
LOW PRES SUPPRESSED TO OUR SOUTH IN THE SPLIT FLOW PATTERN LATE IN
THE WEEK. HOWEVER...AS THE PRECIP SHIELD OF THAT SYSTEM MAY CLIP
THE SOUTHEASTERN PORTIONS OF THE FORECAST AREA...HAVE INCLUDED SLGT
TO CHC POPS FOR FRIDAY INTO FRIDAY NIGHT. HIGH PRESSURE IS
CURRENTLY TIMED TO BRING DRY WEATHER FOR SATURDAY....BUT ANOTHER
FRONT MAY BRING A CHANCE OF SHOWERS FOR SUNDAY..
TEMPERATURES THROUGH THE EXTENDED MODERATE TOWARD AVERAGE. WITH A
SPLIT FLOW LIKELY TO BE IN PLACE...OUR AREA SHOULD REMAIN LARGELY
LOCKED BETWEEN THE NORTHERN AND SOUTHERN STREAM. AS A RESULT...NO
WILD SWINGS OF TEMPS ARE ANTICIPATED.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
A RELATIVELY DRY COLD FRONT WILL CROSS THE TERMINALS THIS
MORNING...BRINGING A WIND SHIFT FROM SOUTHWESTERLY TO
NORTHWESTERLY WITH ITS PASSAGE. THE FRONT WILL CROSS THE TERMINALS
BETWEEN 09Z AND 13Z. WINDS BEHIND THE FRONT WILL INCREASE TO
AROUND 15KTS WITH GUSTS UP TO 25KTS LATE THIS MORNING INTO THE
AFTERNOON.
WITH LITTLE PRECIPITATION EXPECTED OTHER THAN A STRAY SPRINKLE OR
FLURRY...VFR CONDITIONS ARE FORECAST ACROSS MOST OF THE
TERMINALS THROUGH THE TAF PERIOD. THE EXCEPTION IS AT
KFKL/KDUJ...WHERE TEMPO GROUPS ARE FORECAST FOR MVFR CEILINGS LATE
THIS MORNING.
.OUTLOOK.../TUESDAY THROUGH FRIDAY/...
A COLD NORTHWESTERLY FLOW WILL LEAD TO POSSIBLE RESTRICTIONS AT
KFKL/KDUJ ON TUESDAY AND TUESDAY NIGHT. OTHERWISE...GENERAL VFR
CONDITIONS CAN BE EXPECTED THROUGH THURSDAY NIGHT AS HIGH PRESSURE
BUILDS OVER THE REGION. A LOW PRESSURE SYSTEM PASSING SOUTH OF THE
AREA MAY BRING RAIN TO LOCATIONS SOUTH OF KPIT ON FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GAYLORD MI
952 AM EDT MON APR 1 2013
.SYNOPSIS...
ISSUED AT 422 AM EDT MON APR 1 2013
A SYSTEM IN QUEBEC IS BRINGING COLD AIR AND NORTHWEST WINDS TO THE
STATE TODAY. THE COLDER AIR IS PRODUCING LAKE EFFECT SNOW SHOWERS
WHICH WILL PERSIST OVER NORTHERN MICHIGAN THROUGH TUESDAY. THE MOST
PERSISTENT SNOW SHOWERS WITH THE BEST CHANCE OF ACCUMULATION WILL BE
IN THE TYPICAL SNOW BELTS OF NORTHWEST LOWER AND EAST UPPER
MICHIGAN.
&&
.UPDATE...
ISSUED AT 951 AM EDT MON APR 1 2013
THE STORM SYSTEM WHICH SWEPT ACROSS THE GREAT LAKES THIS WEEKEND...
HAS PUSHED EAST OF THE STATE AND WILL CONTINUE TO LIFT INTO QUEBEC
THROUGH TUESDAY. COLD 850MB TEMPS...NORTHWEST WINDS AND LAKE EFFECT
SNOWS HAD ALREADY BEGUN TO FILTER INTO NRN MI EARLIER THIS MORNING.
850MB TEMPS DROPPED FROM AROUND 0C SUNDAY AFTERNOON TO ARND -16C BY
12Z THIS MORNING.
AS FOR THE REST OF THE AFTN...THE PARAMETERS WHICH ARE CURRENTLY
GENERATING LAKE INDUCED SNOWS OVER THE WRN LAKES...ARE NOT EXPECTED
TO CHANGE MUCH THROUGH 21Z. 850MB TEMPS WILL LINGER AROUND -16C AS
THE AXIS OF THE SFC AND 500MB FEATURES PUSH FURTHER EAST OF THE REGION
THIS AFTERNOON. SFC-850MB WINDS WOBBLE DURING THE AFTN...THOUGH
REMAIN GENERALLY NW (300-320) WHILE INVERSION HEIGHTS LINGER AROUND
5K FT. OVERALL EXPECT WIDESPREAD LAKE SNOWS TO CONT OVER THE WRN
LAKES THROUGH THE AFTN...THOUGH WITH THE HIGH SUN ANGLE...EXPECT
DOMINATE SNOW BANDS TO BECOME A LEAST SLIGHTLY DISRUPTED THROUGH THE
REST OF THE MORNING. OVERALL WILL KEEP CONT TO MENTION LAKE SNOWS
THROUGH THE AFTN. WILL MENTION UP TO 2 INCHES OF SNOW POSSIBLE IN
FAVORED SNOW BELTS...AND WILL EXTEND HEADLINES THRU THE AFTN.
UPDATE ISSUED AT 708 AM EDT MON APR 1 2013
CHANGES THIS HOUR: ADDITIONAL /UPWARD/ ADJUSTMENTS TO SNOWFALL AS
A BAND OF NEARLY 5 INCHES HAS OCCURRED OVER EXTREME SW OTSEGO
COUNTY AND NW CRAWFORD COUNTY. BANDING IS MAKING ITS EXPECTED
SHIFT EAST...AND IS BEGINNING TO BECOME A LITTLE MORE DIFFUSE.
EXPECT WE/VE GOT 2-3 MORE HOURS OF DECENT ACCUMS BEFORE THINGS
WIND DOWN. ADVISORY CONTINUES TO LOOK GOOD AND WILL MAKE NO
CHANGES TO THIS.
UPDATE ISSUED AT 519 AM EDT MON APR 1 2013
CHANGES THIS HOUR: BAND HESITATED LONG ENOUGH FOR ME...AND HAVE
ISSUED A WINTER WEATHER ADVISORY FOR 4 OF THE BIG 5 /EXCLUDED
KALKASKA/ THROUGH NOON. RADAR ESTIMATES HAVE REACHED 2-3" IN
SPOTS...WITH BIG FLUFFY FLAKES FALLING HERE AT THE OFFICE
INDICATING 20:1 RATIOS LOOK GOOD. WINDS AMPLE TO BLOW THIS SNOW
AROUND AS WELL. EXPECT 2-4 OVER THE NEXT FEW HOURS AS BAND STARTS
TO EDGE EAST FROM ITS CURRENT LOCATION...BEFORE LIKELY BREAKING UP
BY LATE MORNING.
NO OTHER CHANGES ATTM.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 422 AM EDT MON APR 1 2013
HIGH IMPACT WEATHER POTENTIAL: GALE FORCE WIND GUSTS POSSIBLE ALL
MARINE WATERS THROUGH TODAY. SNOW/BLOWING SNOW WILL BRING SOME
SLICK TRAVEL AND REDUCED VISIBILITIES TO THE SNOWBELTS OF EASTERN
UPPER/NORTHERN LOWER...WITH SNOW SHOWERS REACHING ALL OTHER LOCALES
AS WELL.
OVERVIEW: WISHING THE EARLY MORNING WATER VAPOR IMAGERY WAS AN APRIL
FOOLS JOKE THIS MORNING AS IMPRESSIVE TROUGH CARVES ITSELF OUT OVER
THE GREAT LAKES REGION. PICKLE LAKE /ONTARIO/ 00Z RAOB SHOWS -42C AT
H5...-25C AT H7 AND -20C AT H8...AN ARCTIC AIRMASS INDEED WITH SURFACE
TEMPS UPSTREAM OF THE GREAT LAKES IN THE LOWER TEENS AND DEWPOINTS
FALLING TO NEAR ZERO. WITH SUBSTANTIAL DOWNSTREAM BLOCKING IN PLACE
FROM GREENLAND SOUTH AND EAST...THE DEVELOPING LONGWAVE TROUGH
OVERHEAD WILL BE IN NO HURRY TO DEPART...WITH ITS IMPACTS DOMINATING
THE SHORT TERM PORTION OF THE FORECAST.
THROUGH DAYBREAK: APX WSR-88D SHOWING LAKE EFFECT SNOW GETTING IT/S
ACT TOGETHER OVER NORTHERN LOWER...WITH PRIMARY BAND FROM ACB-GOV
STRENGTHENING WITH GOOD LAKE SUPERIOR CONNECTION. EXPECT THIS TREND
TO CONTINUE THROUGH DAYBREAK WITH AN INCH OR TWO OF SNOW POSSIBLE
OVER THE BIG 5 OF NW LOWER. WILL COVER THIS BAND WITH AN SPS FOR A
QUICK 1-2 INCHES WHICH WILL LIKELY IMPACT THE MONDAY MORNING
COMMUTE.
WINDS REMAIN QUITE BRISK AS 6MB/6HR PRESSURE RISE CENTER OVER
NORTHERN LAKE SUPERIOR SLIDES SOUTH AND EAST...WITH 15-25 MPH WINDS
THROUGHOUT NORTHERN MICHIGAN...GUSTING AS HIGH AS 35 MPH NEAR THE
COASTS.
TODAY: WITH THE CORE OF THE H5 LOW PUSHING FROM JUST NORTH OF THE
SOO EARLY THIS MORNING TO SOUTHWESTERN QUEBEC BY THSI EVENING...OUR
FLOW ALOFT WILL BACK SLIGHTLY AS THE COLDEST AIR ALOFT MAKES ITS
CLOSEST APPROACH. T8 AROUND -17C WITH WHAT LOOKS TO BE ROBUST
LLEVEL MOISTURE /SEE FOG PRODUCT IMAGERY SHOWING ALL KINDS OF
MOISTURE JUST WEST OF THE H5 LOW CENTER /AND THUS...OVERHEAD
TODAY/. THIS SPELLS CONTINUED LAKE EFFECT SNOW SHOWERS UNDER STRONG
NW WINDS. ALL HIGH RESOLUTION GUIDANCE CONTINUES TO SHOW A DOMINANT
BAND TO START THE DAY...WITH THE HRRR LOOKING TO CAPTURE IT/S
LOCATION BEST /FURTHER WEST THAN THE RAP AND LOCAL WRF/. GIVEN THAT
WE ALREADY HAVE A BAND OF THIS NATURE...SEE NO REASON TO DISAGREE
WITH THE GUDIANCE SUGGESTION...WHICH SHOWS THIS BAND STARTING THE
DAY CENTERED FROM CVX-ACB-GOV PUSHING EAST GIVEN THE AFOREMENTIONED
BACKING FLOW...WITH SOMEWHAT LIGHTER SHSN SURROUNDING IT. THE BAND
LOOKS TO BE QUITE MOBILE THROUGH THE MORNING BEFORE CAPE/SHEAR
NOMOGRAM SUGGESTS THAT BY LATE MORNING IT WIL BEGIN TO BREAK UP AS
OVERLAND INSTABILITY STRENGTHENS. THIS BACKING FLOW SHOULD HELP GET
WESTERN CHIPPEWA/MACKINAC BACK INTO THE ACTION DURING THE DAY AS
WELL.
SNOWFALL: MOBILE SNOWBAND WILL KEEP A LID ON SNOW AMOUNTS...BUT
COULD SEE 1-3" FOR THE DAY TODAY OVER THE NW SNOWBELTS...WITH MOST
OF THIS FALLING BEFORE ACTIVITY BECOMES MORE CELLULAR THIS
AFTERNOON.
WHILE WE LOSE HELP FROM ANY ISALLOBARIC COMPONENT TO THE LLEVEL
WINDS TODAY...H9 WINDS 25-30KTS AND AMPLE LLEVEL MIXING SUGGEST
WINDS 15-25 MPH WINDS WITH GUSTS WELL INTO THE 30S...PARTICULARLY
NEAR THE LAKESHORES AND OVER EASTERN UPPER.
TEMPS WILL BE VERY SLOW TO CLIMB WITH T9 AROUND -10C SUGGESTING MID
20S /SOME 20F BELOW NORMAL/ WILL BE ABOUT ALL WE CAN MUSTER. WITH
THE STRONG WINDS...WIND CHILLS WILL REMAIN IN THE TEENS THROUGH THE
DAY.
HEADLINES: WILL GO AHEAD AND DROP WINTER WEATHER ADVISORY FOR
CHIPPEWA GIVEN LOCATION OF SNOWFALL ACTIVITY WELL WEST OF COUNTY
WITH ACCUMS THUS FAR NOT SUFFICIENT TO WARRANT THE HEADLINE.
AS DISCUSSED ABOVE...HEAVIEST SNOW IS NOW OVER THE BIG 5 IN NW
LOWER...AND WILL MONITOR FOR POTENTIAL HEADLINE THROUGH
DAYBREAK...ALTHOUGH EXPECTATION IS THAT THE BAND WILL BEGIN TO
MOVE...REDUCING THE THREAT OF SIGNIFICANT ACCUMS.
TONIGHT: SYNOPTIC MOISTURE BEGINS TO SLOWLY ERODE WITH TEMPS ALOFT
STEADY OR JUST SLIGHTLY WARING UNDER A FAIRLY STEADY 300-310 FLOW
REGIME. SOME RESIDUAL LAND-BASED CAPE CONTINUES THROUGH THE
OVERNIGHT WHICH MAY NOT FULLY ALLOW THE LAKE EFFECT TO RE-SOLIDIFY
INTO BANDS. SHSN WILL CERTAINLY CONTINUE...HOWEVER...WITH
ADDITIONAL LIGHT ACCUMULATIONS LIKELY. INHERITED ACCUMS OF 1-2
INCHES /PERHAPS 3 OVER WESTERN CHIPPEWA/ LOOK REASONABLE AND HAVE NO
COMPELLING REASON TO DEVIATE SIGNIFICANTLY.
CLOUDS WILL LIKELY KEEP TEMPERATURES FROM FALLING ALL THAT FAR...
GENERALLY IN THE UPPER TEENS TO AROUND 20.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 422 AM EDT MON APR 1 2013
TUESDAY...AS THE SFC HIGH BEGINS TO MOVE INTO THE REGION, THE 850 MB
TEMPERATURES BEGIN TO WARM SLIGHTLY, JUST ENOUGH THAT WE MAY LOSE
THE INSTABILITY NEEDED FOR THE LES. THE MOISTURE IN THE 850-700 MB
LAYER FALLS OFF TO BELOW 60% ON ALL THE MODELS SO WOULD EXPECT LIGHT
SNOW AND FLURRIES. ALTHOUGH WILL HAVE LIKELY POPS SINCE MEASURABLE
SNOW IS EXPECTED FROM THIS PATTERN IN THE MORNING. BY THE AFTERNOON,
THE MOISTURE CONTINUES TO FALL OFF IN THE 850-700 MB LAYER. THE ONE
THING THAT I HAVE NOTICED ABOUT THESE LATE SEASON LES EVENTS IS THAT
IT HAS BECOME HARD FOR THE LOWER END OF THE SOUNDINGS TO SATURATE.
THIS HAS BEEN LEADING TO INVERTED V SOUNDINGS AND REALIZING LESS
SNOW THAN WE WOULD HAVE EVEN A MONTH AGO DURING THE AFTERNOON.
TUESDAY NIGHT...AS THE RIDGE BUILDS INTO THE REGION, THE DRIER AIR
REALLY BEGINS TO OVERWHELM THE REGION, SHUTTING OFF MOST OF THE SNOW
LEAVING ONLY CHANCE POPS IN THE EVENING IN E UPPER, WHILE N LOWER
WILL BE DRY ENOUGH TO NOT HAVE ANY SNOW.
WEDNESDAY...HIGH PRESSURE AT THE SFC AND 500 MB RIDGE MOVES THROUGH
THE REGION SO THAT WE WILL REMAIN DRY FOR THE DAY. OVERNIGHT, A COLD
FRONT AND 500 MB SHORTWAVE TROUGH MOVE INTO THE REGION. THE GFS IS A
LITTLE FASTER THAN THE ECMWF AND NAM. WILL HOLD OFF THE SNOW BY
ALLOWING IT TO JUST TOUCH E UPPER BY 12Z.
EXTENDED (THURSDAY THROUGH SUNDAY)...THURSDAY, THE MODELS DRY THINGS
OUT WITH THE FRONTAL PASSAGE DURING THE DAY. SO WILL HAVE CHANCE
POPS WITH A MIX OF THE RAIN AND SNOW IN E UPPER AND JUST RAIN IN N
LOWER. WITH THE SFC TEMPERATURES IN THE 40S, WOULD NOT BE SURPRISED
IF THIS TURNS OUT TO BE FLURRIES AND SPRINKLES. FRIDAY, THE HIGH
BUILDS INTO THE UPPER GREAT LAKES REGION AND DRIES THINGS OUT AGAIN.
SO DRY WEATHER WILL BE EXPECTED. SATURDAY, THE WARM FRONT WILL BE
MOVING INTO THE REGION. THE ECMWF HAS THE WARM AIR INTO E UPPER SO
THAT IT COULD BE ALL RAIN, WHILE THE GFS HAS IT PLACED A LITTLE
SOUTH. PUT THE DIVIDING LINE AT THE STRAITS SINCE THAT SEEMED TO BE
THE MIDDLE GROUND. WHICH WOULD CONTINUE THROUGH THE NIGHT AS THE
SYSTEM MOVES EAST. SUNDAY, THE LOW MOVES EAST OF THE REGION AND THE
COLD AIR MOVES BACK IN ALLOWING FOR A CHANGE OVER TO SNOW. THE GFS
DRIES THINGS OUT. WILL LEAN TOWARD THE ECMWF WHICH WOULD BE THE
PESSIMISTIC FORECAST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 708 AM EDT MON APR 1 2013
SUMMARY: STRONG LOW PRESSURE...DEPARTING INTO EASTERN CANADA WILL
CAUSE STRONG NORTHWEST WINDS THROUGH THE UPCOMING TAF PERIOD...WITH
OCCASIONAL LAKE EFFECT SNOW SHOWERS IMPACTING THE TAF SITES.
RESTRICTIONS: LAKE EFFECT SNOW BANDS DOING A GOOD JOB AVOIDING THE
TERMINALS EARLY THIS MORNING. PRIMARY BAND FROM CHARLEVOIX TO
GAYLORD WILL START TO BREAK UP AS IT SHIFTS EAST...BUT WILL LIKELY
BRING A PERIOD OF MVFR/IFR TO PLN FOR A TIME THIS MORNING. LAKE
EFFECT SHSN WILL CONTINUE THIS AFTERNOON...BUT IN A MORE
CELLULAR/SCATTERED FASHION...WHICH WILL LIKELY ALLOW TVC/MBL/APN TO
REMAIN VFR WHILE PLN DEALS WITH OCCASIONAL MVFR VSBYS-CIGS /WITH
PERHAPS VERY BRIEF IFR VSBYS/. SHSN ACTIVITY WILL CONTINUE
TONIGHT...BUT WILL AVOID INCLUDING MVFR/IFR RESTRICTIONS IN THIS TAF
PACKAGE AS THESE SHSN WILL BE SHORT-LIVED AND CONFIDENCE NOT HIGH
ENOUGH ON LOCATION /ALTHOUGH BEST CHANCES WILL LIKELY CONTINUE TO BE
AT PLN/ TO INCLUDE.
WINDS: NORTHWEST WINDS WILL REACH 18G28KTS FOR THE DAY TODAY BEFORE
DIMINISHING TO 10-15KTS TONIGHT.
&&
.MARINE...
ISSUED AT 422 AM EDT MON APR 1 2013
UPDATE AT 708 AM...DROPPED GALE WARNINGS FOR ALL AREAS SAVE
WHITEFISH BAY AND THE COAST OF NORTHERN LAKE HURON. HIGH END SMALL
CRAFTS SHOULD SUFFICE THROUGH TODAY AND WILL NEED EXTENDING BEYOND
TONIGHT IN SUBSEQUENT UPDATES.
SUMMARY: STRONG NORTHWESTERLY WINDS TO CONTINUE THROUGH TUESDAY AS
LOW PRESSURE MOVES INTO EASTERN CANADA. HIGH PRESSURE ARRIVES BY
MIDWEEK WITH QUIETER CONDITIONS EXPECTED.
HEADLINES: MARGINAL GALES WILL BE ALLOWED TO CONTINUE ALL ZONES
THROUGH THIS EVENING. SMALL CRAFTS WILL CERTAINLY BE NEEDED BEYOND
THIS...WITH ADDITIONAL GALE FORCE GUSTS POSSIBLE AGAIN
TUESDAY...PARTICULARLY FOR NORTHWESTERLY FLOW FAVORED REGIONS.
BEYOND THIS...NEXT ROUND OF SMALL CRAFTS LOOKS LIKELY BY WEDNESDAY
NIGHT OVER LAKE MICHIGAN AS SOUTHWESTERLY WINDS STRENGTHEN AHEAD OF
NEXT APPROACHING SYSTEM.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL NOON EDT TODAY FOR MIZ019-021-022-
028.
LH...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LHZ345-346-
349.
GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LHZ347-348.
LM...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LMZ323-341-
342-344>346.
LS...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LSZ322.
GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LSZ321.
&&
$$
UPDATE...SR
SYNOPSIS...JL
SHORT TERM...ARNOTT
LONG TERM...JL
AVIATION...ARNOTT
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
728 AM EDT MON APR 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 440 AM EDT MON APR 1 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF
CENTERED FM HUDSON BAY INTO THE GRT LKS DOWNSTREAM OF UPR RDG OVER
WRN CANADA. 00Z H5/H85 TEMPS ARE AS LO AS -42C/-20C AT THE CORE OF
THE COLDEST AIR AT YPL. CYC NNW FLOW ON THE WRN FLANK OF LO PRES
MOVING SLOWLY E INTO QUEBEC IS DRAWING THIS VERY COLD AIR SWD INTO
THE UPR LKS OVER THE RELATIVELY WARM WATERS OF LAKE SUP...WITH THE
RESULT NMRS LES BANDS AS SHOWN ON MQT RADAR. WELL DEFINED AXIS OF
COLDER CLD TOPS AS SHOWN ON IR STLT IMAGERY IS PRESENT OVER THE E
HALF OF THE LK AND ASSOCIATED WITH FAIRLY SHARP H7-3 QVECTOR CNVGC.
THIS AXIS OF DEEPER MSTR HAS CAUSED SOME ENHANCEMENT TO THE SHSN.
THE HEAVIEST BAND IS STREAMING INTO CENTRAL ALGER COUNTY/SCHOOLCRAFT
COUTY...WITH SOME RETURNS AOA 30 DBZ AT 06Z. SN UNDER THIS BAND IS
LIKELY FALLING AT THE RATE OF AT LEAST AN INCH/HR GIVEN FAVORABLE
LOCATION OF UVV MAX WITHIN DGZ AS SHOWN BY PROFILE FM LOCAL HI RES
MODEL. SINCE THE COLDER CLD TOPS ARE TENDING TO DRIFT TO THE E AND
DRIER LLVL AIR SHOWN ON THE 00Z INL RAOB IS PRESSING TO THE E...
DROPPING THE SFC DEWPT TO NEAR 7F AT IWD AT 06Z...THE INTENSITY OF
THE LES W OF MQT HAS TENDED TO DIMINISH OVER TIME PER RADAR TRENDS
EVEN THOUGH IR STLT IMAGERY INDICATES SOME LES BANDS OVER THE W HALF
OF THE LK THAT HAVE FORMED IN THE PRESENCE OF NOCTURNAL COOLING THAT
IS SO IMPORTANT TO ACHIEVE BETTER LES BAND STRUCTURE THIS TIME OF
YEAR. NW WINDS ARE STILL GUSTING AS HI AS 40 KTS AT STANNARD ROCK AS
OF 06Z...BUT PASSAGE OF PRES RISE CENTER TRAILING THE SFC LO INTO
ONTARIO E OF LK SUP HAS CAUSED A SLOW DIMINISHING TREND TO THE WINDS.
MAIN FCST CONCERNS THIS PACKAGE ARE LES TRENDS/GOIND HEADLINES.
TODAY...MODELS INDICATE UPR TROF AXIS WL DRIFT SLOWLY TO THE E. AREA
OF DEEP LYR QVECTOR CNVGC ENHANCING COMMA HEAD/COLDER CLD TOPS NOW
OVER THE E HALF OF LK SUP IS PROGGED TO DRIFT INTO ONTARIO IN THE
09Z-12Z TIME FRAME. IN CONCERT WITH THE ARRIVAL OF SOME DRYING FM
THE W...LES INTENSITY/COVERAGE SHUD DIMINISH BY SUNRISE. BUT GIVEN
PERSISTENCE OF SGNFT BAND OVER CENTRAL ALGER COUNTY INTO NRN
SCHOOLCRAFT COUNTY IN PERSISTENT NNW FLOW THRU THE EARLY MRNG
HRS...FVRBL SN/WATER RATIOS UNDER COLDEST H85 TEMPS...AND HIER RES
MODEL FCSTS THAT SHOWING FAIRLY HI QPF THRU 18Z WITH DEEPER MSTR
PERSISTING LONGEST IN THAT AREA CLOSER TO DEPARTING LO...OPTED TO
UPGRADE GOING ADVY FOR THOSE ZONES TO AN LES WARNING. OTRW...RISING
H5 HGTS/DEEP LYR QVECTOR CNVGC/SUBSIDENCE IN THE PRESENCE OF DIURNAL
HEATING THAT TENDS TO DISRUPT THE LES PROCESS IN EARLY SPRING SHOULD
CAUSE THE LES BANDS TO WEAKEN AND TRANSITION TO A MORE BLOTCHY
APPEARANCE. SLOWLY BACKING FLOW TOWARD MORE WNW BY THE LATE IN THE
DAY WL ALSO CAUSE AREA OF HEAVIER SHSN TO SHIFT. ADDITIONAL SN
AMOUNTS OVER THE W WL BE LIGHT WITH LLVL DRY AIR HAVING A MORE SGNFT
IMPACT THERE AND MODELS HINTING TOWARD A TRANSITION TO LLVL ACYC
FLOW IN THE AFTN.
TONIGHT...STEADILY RISING HGTS/DEEP LYR QVECTOR CNVGC THAT DROPS
FCST INVRN BASE TOWARD 5-6K FT OVER EVEN THE E SUG LES INTENSITY WL
BE SOMEWHAT DIMINISHED EVEN THOUGH PERSISTENT NW FLOW/H85 TEMPS IN
THE -16 TO -17C RANGE WL ALLOW FOR CONTINUED WDSPRD LES...ESPECIALLY
AFTER MID EVNG WHEN IMPACTS OF DAYTIME HEATING WOULD TEND TO
SUBSIDE. WITH INVRN BASE OVER THE W FALLING TO ARND 4K FT OVER THE
W...SHSN INTENSITY IN THIS AREA WL BE WEAKER WITH SHORTER FETCH/LESS
MODERATION OF UPSTREAM AIRMASS. BUT STILL WENT WITH LIKELY POPS
GIVEN FVRBL NW FLOW/OVERWATER INSTABILITY/NOCTURNAL COOLING THAT WL
ALLOW LES BANDS TO REDEVELOP.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 440 AM EDT MON APR 1 2013
DESPITE ADEQUATE DELTA TS PERSISTING INTO TUESDAY FOR LAKE
EFFECT...SFC-H85 FLOW WILL BECOME INCREASINGLY ANTICYCLONIC THROUGH
THE DAY. IN ADDITION...INVERSION HEIGHTS BEGIN TO FALL OFF
SIGNIFICANTLY BELOW 5KFT. THUS...EXPECT OVERALL COVERAGE AND
INTENSITY OF LAKE EFFECT TO BE ON THE WANE AS THE DAY PROGRESSES.
TEMPERATURES WILL REMAIN WELL BELOW NORMAL WITH A SIGNIFICANT AMOUNT
OF CLOUDINESS DOWNWIND OF LAKE SUPERIOR.
LAKE CLOUDS AND EVEN A FEW FLURRIES WILL PERSIST INTO THE MORNING
WEDNESDAY OVER THE EAST. AS SURFACE RIDGE AXIS MOVES OVERHEAD
THROUGH THE DAY EXPECT SKIES TO BECOME MOSTLY SUNNY AREA WIDE.
TEMPERATURES SHOULD REBOUND BACK ABOVE FREEZING AND EVEN APPROACH 40
ACROSS THE WEST WITH WARM ADVECTION INCREASING DURING THE AFTERNOON
AND MORE SUNSHINE.
MODELS COMING INTO BETTER AGREEMENT WITH THE TIMING OF THE NEXT
SHORTWAVE AND SFC TROUGH EXPECTED TO MOVE ACROSS THE AREA WED
NIGHT/THU. THE TREND HAS BEEN TOWARD QUICKER MOVEMENT WITH THE TROUGH.
SYSTEM IS FAIRLY MOISTURE STARVED...SO DESPITE PRECIP TYPE BEING A
CHALLENGE BETWEEN RAIN AND SNOW...AMOUNTS WILL BE LIGHT ENOUGH TO BE
PRETTY INSIGNIFICANT. COLD ADVECTION BEHIND THE TROUGH SHOULD PUSH
85H TEMPS BACK DOWN TO THE -10 TO -14C RANGE BY FRIDAY. PROBABLY NOT
QUITE COLD ENOUGH FOR LAKE EFFECT THIS TIME AROUND...BUT COLDER AIR
WILL KEEP DAYTIME TEMPS BELOW AVERAGE ONLY IN THE 30S.
FORECAST FOR NEXT WEEKEND STILL PRETTY CHALLENGING...BUT MODELS
SHOWING SOME SIGNS THAT THEY ARE TRYING TO CONVERGE ON A MORE
PROBABLE OUTCOME. SHORTWAVE ENERGY AND ASSOCIATED SURFACE LOW MOVING
OUT OF THE PLAINS LOOKING LIKE THEY MAY NOW TRACK THROUGH THE LOWER
LAKES WHICH WOULD STILL RESULT IN SOME LIGHT SNOWFALL ACROSS
SOUTHERN AREAS SATURDAY INTO SUNDAY BUT SPARE THE AREA FROM A MORE
SIGNIFICANT STORM. IT IS STILL SOMETHING TO KEEP AN EYE ON AS WE
HEAD THROUGH THE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 726 AM EDT MON APR 1 2013
ALTHOUGH NW FLOW OF COLD AIR FLOWING ACRS LK SUP MAY CAUSE MVFR
CONDITIONS AT TIMES AT IWD/CMX WITH UPSLOPE WIND COMPONENT...EXPECT
VFR CONDITIONS TO PREDOMINATE AT THESE SITES GIVEN VERY DRY NATURE
OF THE LLVLS UPSTREAM AS SHOWN ON THE 00Z INL/YQD RAOBS. WITH A
DOWNSLOPE WIND COMPONENT AND THIS DRYNESS...SAW HAS THE BEST SHOT TO
REMAIN VFR FOR THE ENTIRE TIME. GUSTY NW WINDS WL LINGER...
ESPECIALLY AT THE MORE EXPOSED CMX LOCATION.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 440 AM EDT MON APR 1 2013
AS LO PRES OVER SE CANADA CONTINUES TO THE E AND THE PRES GRADIENT
WEAKENS...EXPECT NW WINDS TO SLOWLY DIMINISH AND BELOW GALE FORCE
OVER THE CENTRAL BY MID MORNING...SO HASTENED THE ENDING OF THE GALE
WARNINGS FOR THIS AREA. ALTHOUG NW GALES TO 35 KTS WILL CONTINUE
LONGER OVER THE E INTO THIS EVENING...ENDED THE GALES FOR THAT AREA
EARLIER AS WELL. WINDS/WAVES WILL BE SUFFICIENT TO MAINTAIN FREEZING
SPRAY OVER AT LEAST THE E HALF THRU TONIGHT.
WINDS WILL REMAIN PRETTY GUSTY UP TO 30 KNOTS OVER THE EASTERN LAKE
THROUGH THE DAY ON TUESDAY...BUT AS SURFACE RIDGE AXIS PUSHES IN
FROM THE WEST PRESSURE GRADIENT WILL RELAX AND WINDS WILL DIMINISH
DURING THE EVENING. UNTIL THAT TIME...FREEZING SPRAY SHOULD CONTINUE
ACROSS THE EASTERN LAKE. AFTER A BRIEF RESPITE ON
WEDNESDAY...SOUTHWESTERLY WINDS UP TO 25 KNOTS AHEAD OF THE NEXT
TROUGH CROSSING THE LAKE WILL INCREASE WEDNESDAY NIGHT INTO EARLY
THURSDAY BEFORE SHIFTING TO THE NORTHWEST DURING THE DAY THURSDAY
INTO THURSDAY NIGHT. WINDS FOR FRIDAY INTO NEXT WEEKEND SHOULD BE
BELOW 20 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR MIZ007.
LAKE EFFECT SNOW WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR
MIZ006-085.
LAKE SUPERIOR...
GALE WARNING UNTIL 2 AM EDT TUESDAY FOR LSZ250-251-266-267.
GALE WARNING UNTIL NOON EDT TODAY FOR LSZ265.
GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LSZ244-245-264.
GALE WARNING UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ249.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...MZ
AVIATION...KC
MARINE...KC/MZ
AREA FORECAST DISCUSSION...UPDATED
NWS GAYLORD MI
716 AM EDT MON APR 1 2013
.SYNOPSIS...
ISSUED AT 422 AM EDT MON APR 1 2013
A SYSTEM IN QUEBEC IS BRINGING COLD AIR AND NORTHWEST WINDS TO THE
STATE TODAY. THE COLDER AIR IS PRODUCING LAKE EFFECT SNOW SHOWERS
WHICH WILL PERSIST OVER NORTHERN MICHIGAN THROUGH TUESDAY. THE MOST
PERSISTENT SNOW SHOWERS WITH THE BEST CHANCE OF ACCUMULATION WILL BE
IN THE TYPICAL SNOW BELTS OF NORTHWEST LOWER AND EAST UPPER
MICHIGAN.
&&
.UPDATE...
ISSUED AT 708 AM EDT MON APR 1 2013
CHANGES THIS HOUR: ADDITIONAL /UPWARD/ ADJUSTMENTS TO SNOWFALL AS
A BAND OF NEARLY 5 INCHES HAS OCCURRED OVER EXTREME SW OTSEGO
COUNTY AND NW CRAWFORD COUNTY. BANDING IS MAKING ITS EXPECTED
SHIFT EAST...AND IS BEGINNING TO BECOME A LITTLE MORE DIFFUSE.
EXPECT WE/VE GOT 2-3 MORE HOURS OF DECENT ACCUMS BEFORE THINGS
WIND DOWN. ADVISORY CONTINUES TO LOOK GOOD AND WILL MAKE NO
CHANGES TO THIS.
UPDATE ISSUED AT 519 AM EDT MON APR 1 2013
CHANGES THIS HOUR: BAND HESITATED LONG ENOUGH FOR ME...AND HAVE
ISSUED A WINTER WEATHER ADVISORY FOR 4 OF THE BIG 5 /EXCLUDED
KALKASKA/ THROUGH NOON. RADAR ESTIMATES HAVE REACHED 2-3" IN
SPOTS...WITH BIG FLUFFY FLAKES FALLING HERE AT THE OFFICE
INDICATING 20:1 RATIOS LOOK GOOD. WINDS AMPLE TO BLOW THIS SNOW
AROUND AS WELL. EXPECT 2-4 OVER THE NEXT FEW HOURS AS BAND STARTS
TO EDGE EAST FROM ITS CURRENT LOCATION...BEFORE LIKELY BREAKING UP
BY LATE MORNING.
NO OTHER CHANGES ATTM.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 422 AM EDT MON APR 1 2013
HIGH IMPACT WEATHER POTENTIAL: GALE FORCE WIND GUSTS POSSIBLE ALL
MARINE WATERS THROUGH TODAY. SNOW/BLOWING SNOW WILL BRING SOME
SLICK TRAVEL AND REDUCED VISIBILITIES TO THE SNOWBELTS OF EASTERN
UPPER/NORTHERN LOWER...WITH SNOW SHOWERS REACHING ALL OTHER LOCALES
AS WELL.
OVERVIEW: WISHING THE EARLY MORNING WATER VAPOR IMAGERY WAS AN APRIL
FOOLS JOKE THIS MORNING AS IMPRESSIVE TROUGH CARVES ITSELF OUT OVER
THE GREAT LAKES REGION. PICKLE LAKE /ONTARIO/ 00Z RAOB SHOWS -42C AT
H5...-25C AT H7 AND -20C AT H8...AN ARCTIC AIRMASS INDEED WITH SURFACE
TEMPS UPSTREAM OF THE GREAT LAKES IN THE LOWER TEENS AND DEWPOINTS
FALLING TO NEAR ZERO. WITH SUBSTANTIAL DOWNSTREAM BLOCKING IN PLACE
FROM GREENLAND SOUTH AND EAST...THE DEVELOPING LONGWAVE TROUGH
OVERHEAD WILL BE IN NO HURRY TO DEPART...WITH ITS IMPACTS DOMINATING
THE SHORT TERM PORTION OF THE FORECAST.
THROUGH DAYBREAK: APX WSR-88D SHOWING LAKE EFFECT SNOW GETTING IT/S
ACT TOGETHER OVER NORTHERN LOWER...WITH PRIMARY BAND FROM ACB-GOV
STRENGTHENING WITH GOOD LAKE SUPERIOR CONNECTION. EXPECT THIS TREND
TO CONTINUE THROUGH DAYBREAK WITH AN INCH OR TWO OF SNOW POSSIBLE
OVER THE BIG 5 OF NW LOWER. WILL COVER THIS BAND WITH AN SPS FOR A
QUICK 1-2 INCHES WHICH WILL LIKELY IMPACT THE MONDAY MORNING
COMMUTE.
WINDS REMAIN QUITE BRISK AS 6MB/6HR PRESSURE RISE CENTER OVER
NORTHERN LAKE SUPERIOR SLIDES SOUTH AND EAST...WITH 15-25 MPH WINDS
THROUGHOUT NORTHERN MICHIGAN...GUSTING AS HIGH AS 35 MPH NEAR THE
COASTS.
TODAY: WITH THE CORE OF THE H5 LOW PUSHING FROM JUST NORTH OF THE
SOO EARLY THIS MORNING TO SOUTHWESTERN QUEBEC BY THSI EVENING...OUR
FLOW ALOFT WILL BACK SLIGHTLY AS THE COLDEST AIR ALOFT MAKES ITS
CLOSEST APPROACH. T8 AROUND -17C WITH WHAT LOOKS TO BE ROBUST
LLEVEL MOISTURE /SEE FOG PRODUCT IMAGERY SHOWING ALL KINDS OF
MOISTURE JUST WEST OF THE H5 LOW CENTER /AND THUS...OVERHEAD
TODAY/. THIS SPELLS CONTINUED LAKE EFFECT SNOW SHOWERS UNDER STRONG
NW WINDS. ALL HIGH RESOLUTION GUIDANCE CONTINUES TO SHOW A DOMINANT
BAND TO START THE DAY...WITH THE HRRR LOOKING TO CAPTURE IT/S
LOCATION BEST /FURTHER WEST THAN THE RAP AND LOCAL WRF/. GIVEN THAT
WE ALREADY HAVE A BAND OF THIS NATURE...SEE NO REASON TO DISAGREE
WITH THE GUDIANCE SUGGESTION...WHICH SHOWS THIS BAND STARTING THE
DAY CENTERED FROM CVX-ACB-GOV PUSHING EAST GIVEN THE AFOREMENTIONED
BACKING FLOW...WITH SOMEWHAT LIGHTER SHSN SURROUNDING IT. THE BAND
LOOKS TO BE QUITE MOBILE THROUGH THE MORNING BEFORE CAPE/SHEAR
NOMOGRAM SUGGESTS THAT BY LATE MORNING IT WIL BEGIN TO BREAK UP AS
OVERLAND INSTABILITY STRENGTHENS. THIS BACKING FLOW SHOULD HELP GET
WESTERN CHIPPEWA/MACKINAC BACK INTO THE ACTION DURING THE DAY AS
WELL.
SNOWFALL: MOBILE SNOWBAND WILL KEEP A LID ON SNOW AMOUNTS...BUT
COULD SEE 1-3" FOR THE DAY TODAY OVER THE NW SNOWBELTS...WITH MOST
OF THIS FALLING BEFORE ACTIVITY BECOMES MORE CELLULAR THIS
AFTERNOON.
WHILE WE LOSE HELP FROM ANY ISALLOBARIC COMPONENT TO THE LLEVEL
WINDS TODAY...H9 WINDS 25-30KTS AND AMPLE LLEVEL MIXING SUGGEST
WINDS 15-25 MPH WINDS WITH GUSTS WELL INTO THE 30S...PARTICULARLY
NEAR THE LAKESHORES AND OVER EASTERN UPPER.
TEMPS WILL BE VERY SLOW TO CLIMB WITH T9 AROUND -10C SUGGESTING MID
20S /SOME 20F BELOW NORMAL/ WILL BE ABOUT ALL WE CAN MUSTER. WITH
THE STRONG WINDS...WIND CHILLS WILL REMAIN IN THE TEENS THROUGH THE
DAY.
HEADLINES: WILL GO AHEAD AND DROP WINTER WEATHER ADVISORY FOR
CHIPPEWA GIVEN LOCATION OF SNOWFALL ACTIVITY WELL WEST OF COUNTY
WITH ACCUMS THUS FAR NOT SUFFICIENT TO WARRANT THE HEADLINE.
AS DISCUSSED ABOVE...HEAVIEST SNOW IS NOW OVER THE BIG 5 IN NW
LOWER...AND WILL MONITOR FOR POTENTIAL HEADLINE THROUGH
DAYBREAK...ALTHOUGH EXPECTATION IS THAT THE BAND WILL BEGIN TO
MOVE...REDUCING THE THREAT OF SIGNIFICANT ACCUMS.
TONIGHT: SYNOPTIC MOISTURE BEGINS TO SLOWLY ERODE WITH TEMPS ALOFT
STEADY OR JUST SLIGHTLY WARING UNDER A FAIRLY STEADY 300-310 FLOW
REGIME. SOME RESIDUAL LAND-BASED CAPE CONTINUES THROUGH THE
OVERNIGHT WHICH MAY NOT FULLY ALLOW THE LAKE EFFECT TO RE-SOLIDIFY
INTO BANDS. SHSN WILL CERTAINLY CONTINUE...HOWEVER...WITH
ADDITIONAL LIGHT ACCUMULATIONS LIKELY. INHERITED ACCUMS OF 1-2
INCHES /PERHAPS 3 OVER WESTERN CHIPPEWA/ LOOK REASONABLE AND HAVE NO
COMPELLING REASON TO DEVIATE SIGNIFICANTLY.
CLOUDS WILL LIKELY KEEP TEMPERATURES FROM FALLING ALL THAT FAR...
GENERALLY IN THE UPPER TEENS TO AROUND 20.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 422 AM EDT MON APR 1 2013
TUESDAY...AS THE SFC HIGH BEGINS TO MOVE INTO THE REGION, THE 850 MB
TEMPERATURES BEGIN TO WARM SLIGHTLY, JUST ENOUGH THAT WE MAY LOSE
THE INSTABILITY NEEDED FOR THE LES. THE MOISTURE IN THE 850-700 MB
LAYER FALLS OFF TO BELOW 60% ON ALL THE MODELS SO WOULD EXPECT LIGHT
SNOW AND FLURRIES. ALTHOUGH WILL HAVE LIKELY POPS SINCE MEASURABLE
SNOW IS EXPECTED FROM THIS PATTERN IN THE MORNING. BY THE AFTERNOON,
THE MOISTURE CONTINUES TO FALL OFF IN THE 850-700 MB LAYER. THE ONE
THING THAT I HAVE NOTICED ABOUT THESE LATE SEASON LES EVENTS IS THAT
IT HAS BECOME HARD FOR THE LOWER END OF THE SOUNDINGS TO SATURATE.
THIS HAS BEEN LEADING TO INVERTED V SOUNDINGS AND REALIZING LESS
SNOW THAN WE WOULD HAVE EVEN A MONTH AGO DURING THE AFTERNOON.
TUESDAY NIGHT...AS THE RIDGE BUILDS INTO THE REGION, THE DRIER AIR
REALLY BEGINS TO OVERWHELM THE REGION, SHUTTING OFF MOST OF THE SNOW
LEAVING ONLY CHANCE POPS IN THE EVENING IN E UPPER, WHILE N LOWER
WILL BE DRY ENOUGH TO NOT HAVE ANY SNOW.
WEDNESDAY...HIGH PRESSURE AT THE SFC AND 500 MB RIDGE MOVES THROUGH
THE REGION SO THAT WE WILL REMAIN DRY FOR THE DAY. OVERNIGHT, A COLD
FRONT AND 500 MB SHORTWAVE TROUGH MOVE INTO THE REGION. THE GFS IS A
LITTLE FASTER THAN THE ECMWF AND NAM. WILL HOLD OFF THE SNOW BY
ALLOWING IT TO JUST TOUCH E UPPER BY 12Z.
EXTENDED (THURSDAY THROUGH SUNDAY)...THURSDAY, THE MODELS DRY THINGS
OUT WITH THE FRONTAL PASSAGE DURING THE DAY. SO WILL HAVE CHANCE
POPS WITH A MIX OF THE RAIN AND SNOW IN E UPPER AND JUST RAIN IN N
LOWER. WITH THE SFC TEMPERATURES IN THE 40S, WOULD NOT BE SURPRISED
IF THIS TURNS OUT TO BE FLURRIES AND SPRINKLES. FRIDAY, THE HIGH
BUILDS INTO THE UPPER GREAT LAKES REGION AND DRIES THINGS OUT AGAIN.
SO DRY WEATHER WILL BE EXPECTED. SATURDAY, THE WARM FRONT WILL BE
MOVING INTO THE REGION. THE ECMWF HAS THE WARM AIR INTO E UPPER SO
THAT IT COULD BE ALL RAIN, WHILE THE GFS HAS IT PLACED A LITTLE
SOUTH. PUT THE DIVIDING LINE AT THE STRAITS SINCE THAT SEEMED TO BE
THE MIDDLE GROUND. WHICH WOULD CONTINUE THROUGH THE NIGHT AS THE
SYSTEM MOVES EAST. SUNDAY, THE LOW MOVES EAST OF THE REGION AND THE
COLD AIR MOVES BACK IN ALLOWING FOR A CHANGE OVER TO SNOW. THE GFS
DRIES THINGS OUT. WILL LEAN TOWARD THE ECMWF WHICH WOULD BE THE
PESSIMISTIC FORECAST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 708 AM EDT MON APR 1 2013
SUMMARY: STRONG LOW PRESSURE...DEPARTING INTO EASTERN CANADA WILL
CAUSE STRONG NORTHWEST WINDS THROUGH THE UPCOMING TAF PERIOD...WITH
OCCASIONAL LAKE EFFECT SNOW SHOWERS IMPACTING THE TAF SITES.
RESTRICTIONS: LAKE EFFECT SNOW BANDS DOING A GOOD JOB AVOIDING THE
TERMINALS EARLY THIS MORNING. PRIMARY BAND FROM CHARLEVOIX TO
GAYLORD WILL START TO BREAK UP AS IT SHIFTS EAST...BUT WILL LIKELY
BRING A PERIOD OF MVFR/IFR TO PLN FOR A TIME THIS MORNING. LAKE
EFFECT SHSN WILL CONTINUE THIS AFTERNOON...BUT IN A MORE
CELLULAR/SCATTERED FASHION...WHICH WILL LIKELY ALLOW TVC/MBL/APN TO
REMAIN VFR WHILE PLN DEALS WITH OCCASIONAL MVFR VSBYS-CIGS /WITH
PERHAPS VERY BRIEF IFR VSBYS/. SHSN ACTIVITY WILL CONTINUE
TONIGHT...BUT WILL AVOID INCLUDING MVFR/IFR RESTRICTIONS IN THIS TAF
PACKAGE AS THESE SHSN WILL BE SHORT-LIVED AND CONFIDENCE NOT HIGH
ENOUGH ON LOCATION /ALTHOUGH BEST CHANCES WILL LIKELY CONTINUE TO BE
AT PLN/ TO INCLUDE.
WINDS: NORTHWEST WINDS WILL REACH 18G28KTS FOR THE DAY TODAY BEFORE
DIMINISHING TO 10-15KTS TONIGHT.
&&
.MARINE...
ISSUED AT 422 AM EDT MON APR 1 2013
UPDATE AT 708 AM...DROPPED GALE WARNINGS FOR ALL AREAS SAVE
WHITEFISH BAY AND THE COAST OF NORTHERN LAKE HURON. HIGH END SMALL
CRAFTS SHOULD SUFFICE THROUGH TODAY AND WILL NEED EXTENDING BEYOND
TONIGHT IN SUBSEQUENT UPDATES.
SUMMARY: STRONG NORTHWESTERLY WINDS TO CONTINUE THROUGH TUESDAY AS
LOW PRESSURE MOVES INTO EASTERN CANADA. HIGH PRESSURE ARRIVES BY
MIDWEEK WITH QUIETER CONDITIONS EXPECTED.
HEADLINES: MARGINAL GALES WILL BE ALLOWED TO CONTINUE ALL ZONES
THROUGH THIS EVENING. SMALL CRAFTS WILL CERTAINLY BE NEEDED BEYOND
THIS...WITH ADDITIONAL GALE FORCE GUSTS POSSIBLE AGAIN
TUESDAY...PARTICULARLY FOR NORTHWESTERLY FLOW FAVORED REGIONS.
BEYOND THIS...NEXT ROUND OF SMALL CRAFTS LOOKS LIKELY BY WEDNESDAY
NIGHT OVER LAKE MICHIGAN AS SOUTHWESTERLY WINDS STRENGTHEN AHEAD OF
NEXT APPROACHING SYSTEM.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL NOON EDT TODAY FOR MIZ019-021-022-
028.
LH...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LHZ345-346-
349.
GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LHZ347-348.
LM...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LMZ323-341-
342-344>346.
LS...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LSZ322.
GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LSZ321.
&&
$$
UPDATE...ARNOTT
SYNOPSIS...JL
SHORT TERM...ARNOTT
LONG TERM...JL
AVIATION...ARNOTT
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1030 AM EDT MON APR 1 2013
.SYNOPSIS...
A WEAK FRONT WILL MOVE THROUGH AND BRING SCATTERED RAIN SHOWERS
THROUGH THIS AFTERNOON. A STRONGER FRONT WILL MOVE THROUGH TONIGHT
USHERING IN COOL AIR FOR THE MID WEEK PERIOD. GULF OF MEXICO LOW
PRESSURE WILL MOVE UP THE CAROLINA COAST FRIDAY BRINGING A SOAKING
RAIN. NEXT WEEKEND SHOULD BE FAIR AND SEASONABLE.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM MONDAY...SEVERAL FEATURES WORKING TOGETHER TO BRING US
SOME SHOWERS THIS MORNING...AND THESE WILL LINGER INTO THE EARLY
AFTN BEFORE RAPID DRYING OCCURS LATER TODAY.
PRECIP ONGOING AT THIS HOUR IS DRIVEN PRIMARILY BY A VORT MAX MOVING
ACROSS SC. THIS WILL CONTINUE TO WORK EAST THROUGH THE
AFTN...CONTINUING THE CHANCES FOR SHOWERS. BUFR PROFILES SUGGEST
INCREASING INSTABILITY AHEAD OF THE UPPER FEATURE...ESPECIALLY
ACROSS SOUTHERN ZONES WHICH WILL BE MORE DIRECTLY IMPACTED BY THE
IMPULSE MOVING OVERHEAD. HAVE INTRODUCED ISO -TRW FOR THE EXTREME
SOUTHERN ZONES SINCE THERE APPEARS TO BE ENOUGH LIFT AND INSTABILITY
FOR AN ISOLATED LIGHTNING STRIKE THROUGH THE AFTN...BUT NOTHING
WIDESPREAD...AND ANY CHC FOR THUNDER WILL END QUICKLY AS VORT SKIRTS
OFFSHORE.
WEAK COLD FRONT...AND I DON`T LIKE THE TERM COLD FRONT DUE TO LACK
OF ANY TEMP GRADIENT...WILL DROP SOUTH THIS AFTN BEHIND THE
DEPARTING SHORTWAVE. THE COMBINATION OF SOME SUBSIDENCE BEHIND THIS
SHORTWAVE AND DRYING BEHIND THE COLD FRONT (TROUGH) WILL BRING AN
END TO THE SHOWERS EARLY THIS AFTN...WITH RAPID DRYING OCCURRING IN
THE COLUMN THEREAFTER. THIS DRYING WILL ALLOW FOR SOME SUN TO PEEK
THROUGH THIS AFTN/EVE...AND HIGH TEMPS WILL STILL REACH TO 70 OR
HIGHER EVEN BEHIND THE "COLD FRONT" THANKS TO THE APRIL INSOLATION.
A MORE SIGNIFICANT COLD FRONT...THIS ONE ACCOMPANIED BY REAL
CAA...WILL DROP SOUTH TONIGHT AND TEMPS WILL PLUMMET BEHIND IT. THE
EXACT TIMING IS STILL IN QUESTION...BUT IT APPEARS THIS FRONT WILL
DROP THROUGH THE CWA AFTER MIDNIGHT AND HELP MINS FALL TO SEASONABLE
LEVELS...LOW 40S NORTH TO UPPER 40S SOUTH...AND HAVE LEANED ON THE
SLIGHTLY COOLER MAV NUMBERS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...DEEP UPPER CUTOFF NORTH OF NEW ENGLAND STATES ON
TUESDAY HELPING TO PUSH ARCTIC COLD FRONT AND ITS ASSOC MOISTURE OFF
TO THE SOUTH OF THE AREA. THE UPPER LOW WILL BE LIFTING OUT TO THE
NORTH A BIT HOWEVER AND THIS WILL TEMPER THE STRENGTH OF THE COLD
AIR ADVECTION INTO THE CAROLINAS. GUIDANCE HAS COME UP A FEW DEGREES
PAST SEVERAL RUNS BUT HAVE OPTED TO REMAIN A FEW DEGREES BELOW AS
THE VERY SHALLOW NATURE OF THE COLD AIR MAY BUST THE NUMBERS A BIT.
CURRENT FORECAST CAPS HIGHS AT ABOUT 10F BELOW CLIMO. THE SAME
DEVIATION FROM NORMAL IS EXPECTED TUESDAY NIGHT WITH LOWS UPPER
30S/NR 40. ATTENTION TURNS TO SOUTHERN BRANCH AS WE HEAD INTO
WEDNESDAY. THE NORTHERN STREAM UPPER LOW CONTINUES ITS SLOW
LIFTING/PROGRESSING ENERGY MOVING ACROSS TX WILL BEGIN CYCLOGENESIS
IN THE WESTERN GULF. WRF READILY SPREADS CLOUD COVER AND INCREASING
RAIN CHANCES INTO THE REGION LATE WEDNESDAY AND THEN VERY MUCH SO
WEDNESDAY NIGHT. GIVEN THE MID LEVEL CONFLUENCE ALLOWING THE HIGH TO
REALLY HANG ON AND THAT DEWPOINTS WILL INITIALIZE PRETTY LOW FEEL
THAT THIS IS TOO FAST. END OF PERIOD A COMPROMISE BETWEEN GFS AND
WRF.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 3 AM MONDAY...VERY RAINY PERIOD TO START THE LONG TERM AS
SOUTHERN BRANCH FEATURE TAPS COPIOUS GOMEX MOISTURE AND FLINGS IT UP
ACROSS THE CAROLINAS. THERE ARE SOME TIMING DIFFERENCES BETWEEN
VARIOUS GUIDANCE BUT THE BULK OF THE RAINFALL APPEARS TO BE SLATED
FOR THURSDAY NIGHT INTO FRIDAY MORNING. THEREAFTER DEPENDING ON THE
TRACK OF THE LOW A DRY SLOT MAY WORK UP THE COAST. TEMPS ALSO VERY
MUCH HINGE ON THE TRACK OF THE STORM AS EASTERN COUNTIES APPEAR
LIKELY TO SECURELY WARM SECTOR WHERE INLAND ZONES MAY STRUGGLE A
BIT. TOUGH TO SAY HOW QUICK THE DRYING IS LATER FRIDAY DUE TO THE
LAGGING OF THE UPPER TROUGH INCLUDING WRAPAROUND RAIN POTENTIAL
THOUGH SMALL. HIGH BUILDS IN BEHIND THIS SYSTEM FOR THE WEEKEND
AMIDST LOW AMPLITUDE MID LVL FLOW BRINGING A FAIR AMOUNT OF SUN AND
CLIMO TEMPS...EVEN PERHAPS A WARMING TREND.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
AS OF 12Z...MOST OF THE RAIN IS OVER THE WESTERN TERMINALS AT THIS
TIME. TIME HEIGHTS AND HRRR MODEL ARE IN REASONABLE AGREEMENT IN
MOVING THE PRECIP TOWARD THE COAST WITH A FRONT THAT BASICALLY
WASHES OUT AFTER IT EXITS THE COAST THIS AFTERNOON. LOOK FOR
CONDITIONS TO BOUNCE FROM VFR TO MVFR IN THE PRECIP. ALL AREAS WILL
BECOME VFR BY EARLY AFTERNOON AS THE BULK OF THE DEEP MOISTURE
SHIFTS TO THE SOUTHEAST. A STRONGER FRONT MOVES IN TONIGHT. NO
WEATHER ASSOCIATED WITH IT OTHER THAN A WIND SHIFT TO THE NORTH AND
A VFR STRATA CU CEILING.
EXTENDED OUTLOOK...VFR TUESDAY AND WEDNESDAY. SHOWERS AND SUB-VFR
CONDITIONS LIKELY THURSDAY AND FRIDAY AS LOW PRESSURE MOVES UP THE
ATLANTIC COAST.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM MONDAY...BUOY 41008 AND 41013 HAVE FINALLY SHOWN THE
RAPID DROP OFF WE WERE EXPECTING THIS MORNING...AND DROPPED THE SCA
FOR THE NC WATERS AS NEEDED. A SERIES OF COLD FRONTS...THE FIRST
QUITE WEAK...WILL DROP SOUTH ACROSS THE WATERS TODAY. THIS FIRST ONE
CROSSES LATE THIS AFTN...BRINGING A SLIGHT WIND SHIFT TO W/NW AND AN
END TO SHOWERS/TSTMS. THE STRONGER FRONT CROSSES LATE TONIGHT...AND
WILL BE ACCOMPANIED BY A STRONG BUT SHORT-LIVED SURGE OF N/NE WINDS
APPROACHING 20 KTS. WHILE SEAS MAY TICK UPWARD WITH THIS
SURGE...AFTER BEING 2-4 FT MUCH OF THE DAY...DO NOT ANTICIPATE THE
NEED FOR ANY CAUTIONARY STATEMENTS OR HEADLINES ATTM.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...MAIN AREA OF HIGH PRESSURE BUILDING IN FROM THE
NORTH AND WEST IN A FAIRLY RESTRAINED MANNER ON TUESDAY KEEPING THE
CENTER UP IN THE GREAT LAKES. A SMALLER AND POORLY DEFINED CENTER
SLIPS INTO THE CAROLINAS HOWEVER KEEPING GRADIENT VERY LIGHT LEADING
AND TAME WINDS OUT OF THE N/NE. SEAS BEGIN THE PERIOD STIRRED UP
FROM THE NEAR TERM BUT WILL QUICKLY ABATE. THE PARENT AIRMASS DRAWS
A LITTLE CLOSER WEDNESDAY PICKING UP AND SLIGHTLY VEERING THE WINDS.
AS THE HIGH SETTLES ACRS VA BY THE END OF THE PERIOD AND LOW
PRESSURE MARCHES EAST ACROSS THE GULF COAST THERE SHOULD BE AN
ADDITIONAL VEER AND SMALL INCREASE IN WINDS. THE SPEED AT WHICH THIS
HAPPENS IS A LITTLE UNCERTAIN.
.LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 AM MONDAY...MODERATELY STRONG SOUTHERN BRANCH FEATURE COMING
ACROSS THE GULF OF MEXICO ON THURSDAY WHILE WEST ATLANTIC HIGH
PRESSURE PROGRESSES EASTWARD BUT AT A SLOWER SPEED. THIS WILL
INCREASE THE GRADIENT UP AND DOWN THE SOUTHEAST COAST AND A SMALL
CRAFT ADVISORY WILL BE NEEDED. AS THE STORM SYSTEM TURNS TO THE NE
AND MOVES RIGHT UP THE CAROLINA COAST ON AN INLAND TRACK THE STRONG
SW FLOW WILL BE MAINTAINED IF NOT STRENGTHENED. EXPECT A FURTHER
BUILDING OF SEAS FROM ADDED FETCH DURATION IF NOTHING ELSE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TRA/JDW
NEAR TERM...JDW
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...TRA/BJR
MARINE...
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
651 AM EDT MON APR 1 2013
.SYNOPSIS...
A WEAK FRONT WILL MOVE THROUGH AND BRING WIDESPREAD RAIN THIS
MORNING. A STRONGER FRONT WILL MOVE THROUGH TONIGHT USHERING IN COOL
AIR FOR THE MID WEEK PERIOD. GULF OF MEXICO LOW PRESSURE WILL MOVE
UP THE CAROLINA COAST FRIDAY BRINGING A SOAKING RAIN. NEXT WEEKEND
SHOULD BE FAIR AND SEASONABLE.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM MONDAY...LINEAR EXTRAPOLATION OF THE BACK EDGE OF THE
RADAR ECHOES ACROSS EASTERN GEORGIA PLACES IT NEAR FLORENCE AROUND
15Z/10:00 AM EDT...AND IN WILMINGTON AROUND 1730Z/1:30 PM EDT.
THAT IS LIKELY A LITTLE SLOW GIVEN HOW QUICKLY THE UPPER LEVEL
FEATURE AND ITS SUBSEQUENT MID-LEVEL DRYING SHOULD ADVECT EAST
TOWARD THE COAST...SO I FEEL COMFORTABLE WITH A FORECAST STILL
CALLING FOR THE BULK OF THE PRECIP TO BE OFFSHORE BY NOON. 06Z
MODELS MADE NO SIGNIFICANT CHANGES WITH AFTERNOON TEMPERATURES
EITHER. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
A COLD FRONT LIES ACROSS NORTH CAROLINA FROM NEAR CHARLOTTE
NORTHEAST THROUGH FAYETTEVILLE AND GREENVILLE... SEPARATING
SUBTROPICAL AIR TO THE SOUTH FROM A HEAVILY MODIFIED ARCTIC AIRMASS
TO THE NORTH. THIS BOUNDARY WILL SAG SOUTH DURING THE DAY...CLEARING
THE COASTLINE BY MID TO LATE AFTERNOON. IN THE UPPER LEVELS A 500 MB
DISTURBANCE WILL SWEEP OFFSHORE DURING THE LATE MORNING
HOURS...TAKING MOST OF THE DEEP-LAYER MOISTURE WITH IT.
RADAR COMPOSITES SHOW A CONCENTRATED STREAK OF SHOWERS AND EMBEDDED
THUNDERSTORMS EXTENDING FROM CAPE FEAR WESTWARD ACROSS SC TO NEAR
ATLANTA. MODEL SOUNDINGS SHOW SOMETHING WE HAVEN`T SEEN A LOT OF
THIS YEAR: CONVECTIVE INSTABILITY THROUGH A DEEP LAYER OF THE
ATMOSPHERE. CAPE VALUES ARE NOT AND WILL NOT GET VERY HIGH...ONLY A
COUPLE HUNDRED J/KG FOR ANY INITIAL PARCEL LEVEL...BUT GIVEN THE
SYNOPTIC LIFT OCCURRING IN ADVANCE OF THE SHORTWAVE UPRIGHT
CONVECTION HAS DEVELOPED AND MAY CONTINUE THROUGH THE MORNING.
RAINFALL AMOUNTS COULD APPROACH HALF AN INCH ACROSS FLORENCE...
MARION AND WHITEVILLE THIS MORNING.
ONCE THE SHORTWAVE CLEARS THE COAST THERE IS VERY LITTLE SUPPORT
REMAINING FOR SHOWER ACTIVITY. CLOUDS SHOULD ALSO DIMINISH...
ALTHOUGH MODELS CONTINUE TO PAINT BOTH CIRRUS AND SOME BOUNDARY-
LAYER DRIVEN CUMULUS INTO LATE AFTERNOON. SINCE THERE IS LITTLE REAL
COLD ADVECTION BEHIND THIS FIRST COLD FRONT HIGHS SHOULD RISE INTO
THE LOWER TO MID 70S AWAY FROM THE BEACHES...ACTUALLY A FEW DEGREES
ABOVE NORMAL. TONIGHT A SECOND MUCH STRONGER COLD FRONT WILL DIVE IN
FROM THE NORTH SHORTLY AFTER MIDNIGHT...ACCOMPANIED BY A SHIFT TO
NORTH WINDS AND A MORE IMPRESSIVE SHOT OF COLD ADVECTION.
TEMPERATURES WILL FALL IN EARNEST LATE AND LOWS SHOULD REACH THE 40S
EVERYWHERE BY DAYBREAK TUESDAY.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...DEEP UPPER CUTOFF NORTH OF NEW ENGLAND STATES ON
TUESDAY HELPING TO PUSH ARCTIC COLD FRONT AND ITS ASSOC MOISTURE OFF
TO THE SOUTH OF THE AREA. THE UPPER LOW WILL BE LIFTING OUT TO THE
NORTH A BIT HOWEVER AND THIS WILL TEMPER THE STRENGTH OF THE COLD
AIR ADVECTION INTO THE CAROLINAS. GUIDANCE HAS COME UP A FEW DEGREES
PAST SEVERAL RUNS BUT HAVE OPTED TO REMAIN A FEW DEGREES BELOW AS
THE VERY SHALLOW NATURE OF THE COLD AIR MAY BUST THE NUMBERS A BIT.
CURRENT FORECAST CAPS HIGHS AT ABOUT 10F BELOW CLIMO. THE SAME
DEVIATION FROM NORMAL IS EXPECTED TUESDAY NIGHT WITH LOWS UPPER
30S/NR 40. ATTENTION TURNS TO SOUTHERN BRANCH AS WE HEAD INTO
WEDNESDAY. THE NORTHERN STREAM UPPER LOW CONTINUES ITS SLOW
LIFTING/PROGRESSING ENERGY MOVING ACROSS TX WILL BEGIN CYCLOGENESIS
IN THE WESTERN GULF. WRF READILY SPREADS CLOUD COVER AND INCREASING
RAIN CHANCES INTO THE REGION LATE WEDNESDAY AND THEN VERY MUCH SO
WEDNESDAY NIGHT. GIVEN THE MID LEVEL CONFLUENCE ALLOWING THE HIGH TO
REALLY HANG ON AND THAT DEWPOINTS WILL INITIALIZE PRETTY LOW FEEL
THAT THIS IS TOO FAST. END OF PERIOD A COMPROMISE BETWEEN GFS AND
WRF.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 3 AM MONDAY...VERY RAINY PERIOD TO START THE LONG TERM AS
SOUTHERN BRANCH FEATURE TAPS COPIOUS GOMEX MOISTURE AND FLINGS IT UP
ACROSS THE CAROLINAS. THERE ARE SOME TIMING DIFFERENCES BETWEEN
VARIOUS GUIDANCE BUT THE BULK OF THE RAINFALL APPEARS TO BE SLATED
FOR THURSDAY NIGHT INTO FRIDAY MORNING. THEREAFTER DEPENDING ON THE
TRACK OF THE LOW A DRY SLOT MAY WORK UP THE COAST. TEMPS ALSO VERY
MUCH HINGE ON THE TRACK OF THE STORM AS EASTERN COUNTIES APPEAR
LIKELY TO SECURELY WARM SECTOR WHERE INLAND ZONES MAY STRUGGLE A
BIT. TOUGH TO SAY HOW QUICK THE DRYING IS LATER FRIDAY DUE TO THE
LAGGING OF THE UPPER TROUGH INCLUDING WRAPAROUND RAIN POTENTIAL
THOUGH SMALL. HIGH BUILDS IN BEHIND THIS SYSTEM FOR THE WEEKEND
AMIDST LOW AMPLITUDE MID LVL FLOW BRINGING A FAIR AMOUNT OF SUN AND
CLIMO TEMPS...EVEN PERHAPS A WARMING TREND.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 12Z...MOST OF THE RAIN IS OVER THE WESTERN TERMINALS AT THIS
TIME. TIME HEIGHTS AND HRRR MODEL ARE IN REASONABLE AGREEMENT IN
MOVING THE PRECIP TOWARD THE COAST WITH A FRONT THAT BASICALLY
WASHES OUT AFTER IT EXITS THE COAST THIS AFTERNOON. LOOK FOR
CONDITIONS TO BOUNCE FROM VFR TO MVFR IN THE PRECIP. ALL AREAS WILL
BECOME VFR BY EARLY AFTERNOON AS THE BULK OF THE DEEP MOISTURE
SHIFTS TO THE SOUTHEAST. A STRONGER FRONT MOVES IN TONIGHT. NO
WEATHER ASSOCIATED WITH IT OTHER THAN A WIND SHIFT TO THE NORTH AND
A VFR STRATA CU CEILING.
EXTENDED OUTLOOK...VFR TUESDAY AND WEDNESDAY. SHOWERS AND SUB-VFR
CONDITIONS LIKELY THURSDAY AND FRIDAY AS LOW PRESSURE MOVES UP THE
ATLANTIC COAST.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM MONDAY...SEAS ARE FALLING VERY SLOWLY...BUT BASED ON 6
A.M. BUOY OBS IN THE CAPE FEAR VICINITY THE ADVISORY WILL NEED TO
REMAIN POSTED THROUGH AT LEAST 9 A.M.
NO SIGNIFICANT CHANGES HAVE BEEN MADE TO THE FORECAST. PREVIOUS
DISCUSSION FROM 300 AM FOLLOWS...
A COLD FRONT ACROSS INTERIOR NORTH CAROLINA WILL DROP SOUTHWARD
SLOWLY DURING THE DAY...REACHING THE NORTH AND SOUTH CAROLINA
COASTAL WATERS BY LATE AFTERNOON. WINDS WILL GRADUALLY VEER FROM
SOUTHWEST TO WEST IN THE VICINITY OF THIS RATHER WEAK FRONT. SHOWER
AND THUNDERSTORM ACTIVITY WILL OCCUR THIS MORNING MAINLY NORTH OF
MYRTLE BEACH...WITH SHOWERS BECOMING VERY ISOLATED IF NOT TOTALLY
ABSENT THIS AFTERNOON. A SECOND BUT MUCH STRONGER COLD FRONT WILL
ARRIVE FROM THE NORTH AFTER MIDNIGHT TONIGHT...ACCOMPANIED BY A
SHIFT TO NORTH WINDS WITH AN INCREASE IN SPEEDS TO 15-20 KNOTS. AT
THIS TIME IT DOESN`T APPEAR SMALL CRAFT ADVISORIES WILL BE
NEEDED...BUT CONDITIONS WILL CERTAINLY DETERIORATE LATE.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...MAIN AREA OF HIGH PRESSURE BUILDING IN FROM THE
NORTH AND WEST IN A FAIRLY RESTRAINED MANNER ON TUESDAY KEEPING THE
CENTER UP IN THE GREAT LAKES. A SMALLER AND POORLY DEFINED CENTER
SLIPS INTO THE CAROLINAS HOWEVER KEEPING GRADIENT VERY LIGHT LEADING
AND TAME WINDS OUT OF THE N/NE. SEAS BEGIN THE PERIOD STIRRED UP
FROM THE NEAR TERM BUT WILL QUICKLY ABATE. THE PARENT AIRMASS DRAWS
A LITTLE CLOSER WEDNESDAY PICKING UP AND SLIGHTLY VEERING THE WINDS.
AS THE HIGH SETTLES ACRS VA BY THE END OF THE PERIOD AND LOW
PRESSURE MARCHES EAST ACROSS THE GULF COAST THERE SHOULD BE AN
ADDITIONAL VEER AND SMALL INCREASE IN WINDS. THE SPEED AT WHICH THIS
HAPPENS IS A LITTLE UNCERTAIN.
.LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 AM MONDAY...MODERATELY STRONG SOUTHERN BRANCH FEATURE COMING
ACROSS THE GULF OF MEXICO ON THURSDAY WHILE WEST ATLANTIC HIGH
PRESSURE PROGRESSES EASTWARD BUT AT A SLOWER SPEED. THIS WILL
INCREASE THE GRADIENT UP AND DOWN THE SOUTHEAST COAST AND A SMALL
CRAFT ADVISORY WILL BE NEEDED. AS THE STORM SYSTEM TURNS TO THE NE
AND MOVES RIGHT UP THE CAROLINA COAST ON AN INLAND TRACK THE STRONG
SW FLOW WILL BE MAINTAINED IF NOT STRENGTHENED. EXPECT A FURTHER
BUILDING OF SEAS FROM ADDED FETCH DURATION IF NOTHING ELSE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM EDT THIS MORNING FOR AMZ250-
252.
&&
$$
SYNOPSIS...TRA
NEAR TERM...MBB
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...43
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
541 AM MDT MON APR 1 2013
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 240 AM MDT MON APR 1 2013
ACTIVE PROGRESSIVE NORTHERN STREAM FLOW WILL DOMINATE
THE WEATHER IN THE PERIOD...WITH A LARGE SCALE SPLIT FLOW REGIME.
THIS WILL OFFER WARM DOWNSLOPE PAC ORIGIN FLOW INTO THE AREA...ESP
TUE. GREAT LAKES UPPER TROUGH WILL SLOWLY SHIFT EAST WITH DEEP LAYER
RIDGING DEVELOPING TODAY...INITIATING WAA BY THIS AFTERNOON OVER THE
WESTERN FA. THE ONLY FORECAST CONCERN TODAY WILL BE THE EVOLUTION OF
THE CURRENT STRATUS IN PLACE ACROSS THE EASTERN FA...WHICH MAY
HAMPER T RISES. THE ONLY FORECAST MODELS WHICH SEEMS TO HAVE ANY
SORT OF HANDLE ON THE EXISTENCE OF CLOUD COVER IS THE RAP AND LOCAL
WRF...WITH ALL OTHER GUIDANCE REMAINING TOO DRY IN THE LL/S.
RAP/LOCAL WRF BOTH INDICATE THAT INCREASING DRY WESTERLY FLOW AT THE
BL TOP SHOULD HELP ERODE CLOUD COVER WEST TO EAST THROUGH MORNING
AND TRIED TO INCORPORATE THIS IDEA INTO THE GRIDS. ONCE CLOUDS
CLEAR...SKIES WILL REMAIN MOSTLY CLEAR THROUGH THE PERIOD...SAVE FOR
SOME PASSING CIRRUS.
TEMPS WILL REMAIN ON THE COOL SIDE ACROSS MOST OF THE AREA
TODAY...WITH THE SD PLAINS BEING THE COOLEST. NE WY WILL SEE QUICK
RESPONSE TO ENSUING WAA WITH MANY PLACES EXPECTED TO BE IN THE 50S
THERE. HAVE ADJUSTED TEMPS UP SOME...GIVEN LATEST BLENDED GUIDANCE
WITH STRONG INSOLATION EXPECTED. MUCH WARMER CONDITIONS EXPECTED
TUE...WITH 50S AND 60S COMMON MOST PLACES. HAVE WARMED MOST PLACES
A FEW DEGREES TUE...ESP NE WY. STRONG INSOLATION SHOULD SUPPORT
SUPERADIABATS AT MOST LOCATIONS GIVEN WEAK LL FLOW...WITH TEMPS
WARMER THAN CURRENT FORECAST HIGHS CERTAINLY POSSIBLE. THE NEXT
NORTHERN STREAM IMPULSE WILL APPROACH THE REGION TUE...WITH WAA
RAMPING UP...AS WELL AS LL SOUTHERLY FLOW TUE NIGHT. THIS SHOULD
KEEP TEMPS UP AT MANY PLACES OVERNIGHT TUE...GIVEN TURBULENT
MIXING...ESP IN THE LEE DOWNSLOPE AREAS OF THE BH.
.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 240 AM MDT MON APR 1 2013
UPPER LEVEL RIDGE FLATTENS LATE WEDNESDAY AS A COLD FRONT CROSSES
THE AREA...BRINGING A CHANCE FOR RAIN SHOWERS AND AN ISOLATED
THUNDERSTORM. RAIN SHOWERS WILL LINGER INTO THURSDAY...MAINLY ACROSS
NORTHERN PORTIONS OF THE AREA. A MORE UNSETTLED PATTERN WILL DEVELOP
BY THE WEEKEND AS A LARGE UPPER TROF DEVELOPS OVER THE WEST COAST
AND A SERIES OF DISTURBANCES MOVE ACROSS THE NORTHERN PLAINS IN WEST
TO SOUTHWEST FLOW. TEMPERATURES WILL GENERALLY STAY ABOVE AVERAGE
LATE IN THE WEEK AND LIKELY DROP CLOSER TO AVERAGE LEVELS DURING THE
WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 540 AM MDT MON APR 1 2013
MVFR CIGS WILL PERSIST ACROSS THE WESTERN SOUTH DAKOTA PLAINS
THROUGH THE MORNING HOURS BEFORE LIFTING AND SHIFTING EAST BY 18Z.
VFR CONDITIONS ARE THEN EXPECTED THROUGH TUESDAY MORNING.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...JC
LONG TERM...15
AVIATION...15
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1126 AM MDT MON APR 1 2013
.UPDATE...
ISSUED AT 1121 AM MDT MON APR 1 2013
PLAN TO DECREASE POPS SIGNIFICANTLY BETWEEN NOW AND MIDDAY
TOMORROW ACROSS MANY PARTS OF THE REGION. DRY SLOT WILL
SIGNIFICANTLY DECREASE PRECIP CHANCES BETWEEN NOW AND THEN. BEST
CHANCES OF POPS DURING THE NEXT 24H WILL BE OVER FAR E PLAINS AND
C MTN REGIONS. STILL EXPECT LOW CLOUDS TO INVADE ALL OF THE PLAINS
LATER THIS EVENING. UPDATE WILL BE ISSUED AROUND 1 PM.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 420 AM MDT MON APR 1 2013
A SHORTWAVE TROF IS WRAPPING AROUND AN UPR LOW THAT IS OVR THE WRN
STATES...AND IS BRINGING CLOUDS AND SOME PCPN TO PORTIONS OF WRN
CO...SOME OF WHICH WL AFFECT THE CONTDVD THIS MORNING. ALSO THIS
MORNING A FRONT IS CONTINUING TO MOVE SOUTHWARD THROUGH THE SERN
PLAINS AS OF 3AM IT HAD MOVED SOUTH OF THE ARKANSAS RIVER VALLEY.
HAVE SEEN SOME STRATUS DEVELOP BEHIND THIS FRONT IN NE AND PORTIONS
OF NWRN KS. THE HRRR AND NAM12 SHOW LOW LEVEL RH VALUES/STRATUS
BACKING INTO THE FAR SERN PLAINS A LITTLE LATER THIS MORNING...AND
MAYBE BACKING INTO THE FAR ERN PORTIONS OF EL PASO COUNTY. THE NAM
AND THE HRRR KEEP THE FAR SERN PLAINS DRY THRU THE MORNING
HOURS...WHILE THE GFS PRINTS OUT SOME LIGHT QPF ASSOCIATED WITH THE
STRATUS. DO NOT FEEL THAT MEASURABLE PCPN WL OCCUR SO WL KEEP THE
FORECAST DRY OUT EAST...AND WL ONLY HAVE POPS ALONG THE CONTDVD THIS
MORNING. THIS AFTERNOON THE NAM AND GFS SHOW THE BEST PCPN CHANCES
BEING OVR THE CENTRAL CO MTS AND OVR PIKES PEAK AND TELLER COUNTY.
THE NSSL WRF SHOWS PCPN IN THESE AREAS AS WELL...BUT ALSO SHOWS A
BAND OF PCPN MOVING FROM THE SW ACRS THE SWRN MTS...THE SAN LUIS
VALLEY...THE SANGRE DE CRISTO MTS...AND THEN ONTO THE ADJACENT I-25
CORRIDOR BY EARLY EVENING...AND THEN MOVING ACRS THE SERN PLAINS
THRU THE EVENING. WL LEAN CLOSER TO THE WRF`S SOLUTION. SHOULD SEE
SOME LIGHT SNOW ACCUMS OVR THE HIGHEST ELEVATIONS. TEMPS TODAY WL BE
COOLER THAN YESTERDAY OVR THE SERN PLAINS IN THE WAKE OF THE
FRONT...BUT GUIDANCE TEMPS ARE NOT IN GOOD AGREEMENT SO WL SPLIT THE
DIFFERENCE. COULD SEE SOME LOW CLOUDS HANGING AROUND OVR THE FAR
SERN CORNER INTO THE AFTERNOON WHICH WOULD KEEP TEMPS EVEN COOLER
OUT THERE. SOME WRN AREAS WL BE A LITTLE COOLER TODAY...WHILE THE
SAN LUIS VALLEY WL LIKELY SEE TEMPS SIMILAR TO THOSE ON SUN.
OVERNIGHT THE UPR LOW WL MOVE INTO ERN UT AND MUCH OF THE FORECAST
AREA ENDS UP IN THE DRY SLOT...AS SHOW IN THE NAM12...THE NSSL WRF
AND THE GFS. THE CENTRAL MTS WL PROBABLY CONTINUE TO HAVE SOME PCPN
THRU THE NIGHT...BUT SHOULD GENERALLY BE LIGHT. WITH MOIST LOW LEVEL
UPSLOPE OVR THE ERN PLAINS TONIGHT...WIDESPREAD STRATUS IS EXPECTED.
THE ONLY AREA THAT ALL THE MODELS SHOW WIDESPREAD PCPN TONIGHT IS
OVR THE FAR SERN PLAINS...SO WL GO WITH LIKELY POPS IN THAT
AREA...WITH DECREASING POPS WESTWARD TO THE ERN MTS. THE NAM AND
GFS SHOW A FEW HUNDREDTHS OF PCPN OVR THE FAR ERN AREAS OVERNIGHT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 420 AM MDT MON APR 1 2013
TUESDAY AND WEDNESDAY...THE UPPER LOW PRES SYSTEM TRACKS FROM THE NW
TO THE SE DIRECTLY ACROSS COLORADO ON TUE AND WED...BRINGING A
DECENT SHOT AT SOME PCPN FOR THE FORECAST AREA. STARTING OUT TUE
MORNING...THE UPPER SYSTEM SHOULD BE PRODUCING SOME SHOWERS FOR THE
CENT MTS...WHILE LLVL EASTERLY UPSLOPE FLOW DUE TO SFC HI PRES OVER
NE AND KS WILL KEEP A SOLID THREAT OF PCPN FOR THE EASTERN PLAINS.
HOWEVER...AS THE UPPER LOW CONTINUES TO TRACK ACROSS THE
STATE...PCPN CHANCES SPREAD TO MUCH OF THE AREA BY TUE AFTN AND
REMAIN PROBABLE THROUGH THE NIGHT. ONGOING POP GRIDS LOOKED
REASONABLE FOR TUE NIGHT AND EARLY WED MORN WITH ONLY SLIGHT
ADJUSTMENTS NEEDED. THE TROUGH AXIS EXITS THE SE CORNER OF THE STATE
WED MID-MORNING...WITH PCPN THEN TAPERING OFF QUICKLY. AS FOR
TEMPS...MAX TEMPS IN THE 40S FOR TUE WILL GRADUALLY WARM INTO THE
50S FOR WED.
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT..THE REGION DRIES OUT AS AN
UPPER RIDGE OF HIGH PRESSURE MOVES ACROSS THE 4 CORNERS. TEMPS
SHOULD REMAIN COOL FOR WED...THEN REBOUND INTO THE MID TO UPPER 60S
FOR THU.
FRIDAY THROUGH SUNDAY...THE EXTENDED MODELS WANT TO KEEP THINGS A
BIT UNSETTLED OVER THE WEEKEND. ONE DISTURBANCE ROLLS ACROSS THE
ROCKIES ON FRIDAY BUT LOOKS LIKE IT WILL STAY MAINLY TO THE NORTH OF
THE STATE. A BRIEF BREAK ON SAT...THEN SAT NIGHT ANOTHER SHORTWAVE
TRACKS ACROSS THE GREAT BASIN AND DIGS FURTHER SOUTH...PROMISING A
BETTER SHOT AT SOME BENEFICIAL PCPN. FOR THE TIME BEING...KEPT
ISOLATED POPS OVER THE MTS OVER THE WEEKEND AS THE EXTENDED
PROCEDURE PRODUCED...AND WILL HAVE TO FINE TUNE AS THAT WINDOW
NEARS. FOR THE TIME BEING...FRIDAY LOOKS LIKE THE WARMEST DAY OF THE
EXTENDED FORECAST PERIOD. MOORE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1121 AM MDT MON APR 1 2013
I DO NOT EXPECT ANY SIGNIF PRECIP IN THE TAFS (KCOS...KPUB...KALS)
NEXT 24H. MAIN CONCERN WILL BE LOW CIGS MOVING INTO KCOS AND KPUB
AROUND MIDNIGHT TONIGHT AND LASTING THROUGH THE END OF THE TAF PD.
MVFR CIGS ARE LIKELY AT KPUB AND KCOS AFTER MIDNIGHT TONIGHT.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HODANISH
SHORT TERM...28
LONG TERM...MOORE
AVIATION...HODANISH
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1018 AM MDT MON APR 1 2013
.UPDATE...NO CHANGES TO THE FORECAST ANTICIPATED THIS TIME AROUND.
UPPER LOW CENTER HAS MOVED INTO SOUTHWESTERN UTAH WITH DEFORMATION
BAND CLOUDINESS OUT AHEAD OF IT SPREADING OVER WESTERN AND CENTRAL
COLORADO. RECENT LIGHTNING DATA PLOTS HAVE SHOWN SOME STRIKES TO
THE SOUTH OF VERNAL...UTAH AND ONE OR TWO FLASHES AROUND KGJT.
THIS IS INDICATIVE OF THE INSTABILITY PRESENT IN THE DEFORMATION
ZONE. THE CURRENT FORECASTS ALREADY MENTION SOME THUNDER OVER THE
MOUNTAINS THIS AFTERNOON...WHICH WILL BE LEFT ALONE. KCCU IS ALSO
INDICATING SOME SNOW ALREADY FALLING OVER THE HIGHER MOUNTAINS.
ACROSS THE EASTERN COLORADO PLAINS...EASTERLY FLOW WILL PERSIST
THROUGH THE DAY WHICH MAY HELP SHOWER ACTIVITY TO DEVELOP ALONG
THE FOOTHILLS LATE IN THE AFTERNOON. EACH OF THESE FEATURES IS
ADEQUATELY COVERED IN THE CURRENT FORECAST.
&&
.AVIATION...HIGH CEILINGS WILL BE DEVELOPING BY EARLY AFTERNOON
AND THEN BEGIN LOWERING BY EVENING. SCATTERED SHOWERS WILL BE
POSSIBLE THROUGH THE EVENING...BUT MOST ACTIVITY SHOULD BE CLOSER
TO THE FOOTHILLS. WINDS SHOULD REMAIN OUT OF THE EAST AND
SOUTHEAST THROUGH THE AFTERNOON. A MIX OF RAIN AND SNOW SHOWERS
ARE EXPECTED OVERNIGHT WITH A COMPLETE CHANGEOVER TO SNOW POSSIBLE
BEFORE SUNRISE TUESDAY. TEMPERATURES SHOULD BE JUST COLD ENOUGH TO
ALLOW SNOW TO FALL...BUT GROUND TEMPERATURES SHOULD BE WARM ENOUGH
TO LIMIT ANY ACCUMULATION.
&&
.PREV DISCUSSION... /ISSUED 340 AM MDT MON APR 1 2013/
SHORT TERM...AN UPPER LEVEL LOW WILL MOVE FROM NEVADA INTO UTAH
BY THIS EVENING. AHEAD OF THE LOW THE FLOW ALOFT WILL BE SWLY. AT
THE SURFACE HIGH PRES WILL BE OVER THE CNTRL PLAINS WITH LOW PRES
OVER WRN COLORADO. THIS WILL LEAD TO SELY LOW LVL FLOW OVER NERN
CO THRU TONIGHT. CROSS- SECTIONS SHOW AN INCREASE IN MOISTURE WITH
SOME MID LVL QG ASCENT MAINLY LATE TONIGHT. LAPSE RATES ARE BEST
OVER THE HIGHER TERRAIN WITH LESS INSTABILITY OVER THE PLAINS. AT
THIS TIME THE BEST CHC OF PCPN THRU THIS AFTN LOOKS TO BE IN THE
MTNS WITH DRY CONDITIONS OVER THE PLAINS. WILL MENTION SOME
THUNDER IN THE MTNS WHERE SOME CAPE EXISTS. HIGHS THIS AFTN OVER
NERN CO WILL RANGE FM THE UPPER 40S TO LOWER 50S EXCEPT POSSIBLY
ALONG THE FRONT RANGE WHERE SELY LOW LVL WINDS COMING OFF THE
PALMER DIVIDE COULD ALLOW FOR READINGS TO RISE INTO THE MID TO
UPPER 50S NR DENVER. THE RAP SHOWS HIGHS IN THE LOWER TO MID 60S
AROUND DENVER HOWEVER WILL NOT GO THIS WARM.
FOR TONIGHT SNOW SHOWERS WILL CONTINUE IN THE MTNS DUE TO INCREASING
QG ASCENT HOWEVER SWLY OROGRAPHIC FLOW MAY KEEP ACCUMULATIONS ON
THE LIGHT SIDE IN MOST AREAS. EAST OF THE MTNS THE LOW LVL FLOW
WILL REMAIN SELY. SHOULD SEE SOME SHOWERS DVLP IN THE FOOTHILLS BY
EARLY EVENING WITH SOME OF THE ACTIVITY SPREADING ACROSS THE
ADJACENT PLAINS OVERNIGHT. WITH SELY LOW LVL FLOW THE BEST CHC OF
PCPN MAY FOCUS IN THE NRN FOOTHILLS AND NORTH OF A DENVER TO LIMON
LINE. AT THIS TIME OVERALL CONFIDENCE IS NOT VERY HIGH AS TO WHERE
TO MENTION LIKELY POPS OVER THE PLAINS TONIGHT SO WILL KEEP POPS
IN THE CHC CATEGORY. SOUNDINGS SHOW WET BULB ZEROS WILL BECOME LOW
ENOUGH FOR SHOWERS TO MIX WITH OR CHANGE TO SOME SNOW AFTER
MIDNIGHT ACROSS THE PLAINS HOWEVER AT THIS TIME IT LOOKS LIKE ANY
ACCUMULATION WILL BE AN INCH OR LESS.
LONG TERM...MODELS HAVE THE UPPER CLOSED LOW OVER EAST CENTRAL
UTAH...THEN OVER THE FOUR CORNERS AT 00Z TUESDAY AFTERNOON. BY 18Z
WEDNESDAY...ITS OVER SOUTHEASTERN/ WESTERN KANSAS. ON WEDNESDAY
NIGHT...INCREASING NORTHWESTERLY FLOW ALOFT IS PROGGED FOR THE
FORECAST AREA. THE QG VERTICAL VELOCITY FIELDS HAVE UPWARD MOTION
OVER THE CWA TUESDAY AND TUESDAY NIGHT ...HOWEVER IT IS NOT VERY
STRONG. WEAK DOWNWARD MOTION IS PROGGED WEDNESDAY AND WEDNESDAY
NIGHT. NORTHEAST TO SOUTHEASTERLY LOW LEVEL WINDS ARE PROGGED FOR
THE PLAINS AND FOOTHILLS TUESDAY AND TUESDAY EVENING. WEAK FLOW IS
PROGGED THE REST OF TUESDAY NIGHT THROUGH WEDNESDAY...WITH A
COMBINATION OF NORMAL DUIRNAL PATTERNS TO WEAK DOWNSLOPING
WEDNESDAY NIGHT. MOISTURE IS FAIRLY DEEP ON TUESDAY FOR MOST OF
THE CWA. IT IS PRETTY DEEP ON THE NAM TUESDAY NIGHT...DRIER ON THE
GFS. IT DRIES OUT SOMEWHAT ON WEDNESDAY. THERE IS SOME MOUNTAIN
MOISTURE WEDNESDAY NIGHT...BUT ITS DRIER ON THE PLAINS. MODELS
SHOW MINOR CAPE OVER THE MOUNTAINS AND FOOTHILLS LATE DAY TUESDAY
AND AGAIN WEDNESDAY AFTERNOON. THE QPF FIELDS SHOW MEASURABLE
PRECIPITATION TUESDAY AND TUESDAY EVENING FOR MOST AREAS...BEST
OVER THE FOOTHILLS AND EASTERN MOUNTIANS ZONES. THERE IS A TAD THE
REST OF TUESDAY NIGHT AND WEDNESDAY... MAINLY OVER THE MOUNTIANS.
FOR POPS...WILL KEEP THE "LIKELY"S IN OVER THE MOUNTAINS AND
"CHANCES" OUT ON THE PLAINS TUESDAY AND TUESDAY EVENING. THE
PLAINS WILL SEE BOTH SNOW AND RAIN...WITH LITTLE ACCUMULATION.
WILL DECREASE POPS THE REST OF TUESDAY NIGHT. ON WEDNESDAY...JUST
SOME MINOR ALPINE POPS. WILL PUT "ISOLATED" THUNDER IN BOTH
TUESDAY AND WEDNESDAY AFTERNOONS IN THE MOUNTIANS. FOR
TEMPERATURES...TUESDAY`S HIGHS ARE 2.0-3.5 C COOLER THAN TODAY`S
EXPECTED HIGHS. WEDNESDAY`S READINGS COME UP 3-7 C FROM TUESDAY`S.
FOR THE LATER DAYS...THURSDAY THROUGH SUNDAY...MODELS HAVE UPPER
RIDGING FOR COLORADO THROUGH MID DAY FRIDAY...THEN A WEAK UPPER
TROUGH IS PROGGED ACROSS THE STATE BY EARLY SATURDAY MORNING.
AFTER THAT...WEST-SOUTHWESTERLY FLOW ALOFT IS PROGGED OVER THE CWA
THROUGH SUNDAY. THERE IS LIMITED MOISTURE AROUND...BUT IT
INCREASES ON SUNDAY.
AVIATION...SO FAR ANY STRATUS WAS CONFINED TO THE FAR NERN CORNER
OF THE PLAINS SO AT THIS POINT IT DOES NOT APPEAR IT WILL AFFECT
THE AIRPORT THIS MORNING. AS FOR WINDS BOTH THE RAP AND HRR SHOW A
DENVER CYCLONE DEVELOPING SW OF DENVER WITH WINDS BEING E TO SE
THRU THE AFTN. COULD SEE SUSTAINED WINDS IN THE 15 TO 20 MPH BY
20Z. AT THIS TIME ANY CHC FOR RAIN SHOWERS WILL BE AFTER 00Z.
COULD SEE SHOWERS CHANGE TO SOME SNOW AFTER MIDNIGHT BUT ANY
ACCUMULATION WILL BE UNDER ONE HALF INCH AND CONFINED TO GRASSY
AREAS. LATEST NAM CONTINUES TO SHOW A CYCLONE OVERNIGHT OVER
DENVER WITH WINDS BECOMING MORE SLY AFTER MIDNIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DANKERS
LONG TERM....99
AVIATION...DANKERS
AREA FORECAST DISCUSSION
NWS MIAMI FL
150 PM EDT MON APR 1 2013
.AVIATION...
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE DEVELOPING
ACROSS THE EASTERN PORTION OF THE PENINSULA THIS AFTERNOON. FOR
THE VERY SHORT TERM...SHOWERS AND THUNDERSTORMS ARE IN THE
VICINITY OF TERMINALS KTMB...KMIA AND KOPF WITH BRIEF PERIODS OF
IFR CONDITIONS POSSIBLE. THERE IS A SLIGHT RISK OF SEVERE WEATHER
WITH ANY THUNDERSTORMS THAT DEVELOP THIS AFTERNOON AND EARLY
EVENING. AFTER THE EARLY EVENING HOURS THE POTENTIAL FOR
CONVECTION WILL START TO DECREASE. FOR THE EAST COAST
TERMINALS...AS SOUTHWESTERLY WINDS CONTINUE TO DEVELOP THE CHANCES
OF A SEA BREEZE THIS AFTERNOON ARE DIMINISHING BUT WINDS COULD BE
SOMEWHAT VARIABLE AT TIMES.
60
&&
.PREV DISCUSSION... /ISSUED 1031 AM EDT MON APR 1 2013/
UPDATE...
THE MORNING SURFACE ANALYSIS SHOWED A HIGH PRESSURE RIDGE AXIS
EXTENDING WEST ACROSS SOUTH FLORIDA AND THE SOUTHEAST GULF OF
MEXICO AND A COLD FRONT APPROACHING FROM THE NORTH. SSW LOW-LEVEL
FLOW IS EXPECTED TO GRADUALLY VEER TOWARD THE WEST THROUGH THE
COURSE OF THE DAY AS THIS BOUNDARY CONTINUES SOUTH. THIS FLOW
COMBINED WITH THE AFTERNOON EAST COAST SEA BREEZE...A COUPLE OF
IMPULSES ALOFT AND MODERATE INSTABILITY AND SHEAR (0-6KM 30-35 KT)
COULD GENERATE A FEW STRONG TO EVEN SEVERE THUNDERSTORMS THROUGH
THE AFTERNOON/EVENING PERIOD TODAY OVER THE METRO/EAST COAST
LOCATIONS. THE LATEST WRF AND HRRR MODEL REFLECTIVITIES...
HOWEVER...ARE ONLY INDICATING ISOLATED COVERAGE OVER THESE AREAS
AT BEST THROUGH THIS TIME. ANY STORMS THAT DO INITIATE COULD BE
CAPABLE OF PRODUCING STRONG WINDS, HAIL AND POSSIBLY A TORNADO.
THE LATEST FORECAST HAS BEEN UPDATED TO REFLECT THIS POTENTIAL
THIS AFTERNOON. ELSEWHERE...VISIBILITIES HAVE BEGUN TO IMPROVE
OVER THE PAST HOUR ACROSS THE INTERIOR LOCATIONS FROM THE EARLY
MORNING FOG AND THIS TREND IS EXPECTED TO CONTINUE. THE LOCAL
OFFICIALS HAVE REPORTED THAT SEGMENTS OF I-75 HAVE BEEN CLOSED
TODAY DUE TO A COMBINATION OF THIS FOG EARLIER AND SMOKE FROM THE
ONGOING WILDFIRE IN COLLIER COUNTY.
PREV DISCUSSION... /ISSUED 739 AM EDT MON APR 1 2013/
AVIATION...
AN UPPER LEVEL SHORTWAVE ACROSS THE EASTERN GULF WILL MOVE ACROSS
THE FLORIDA PENINSULA TODAY. A FEW SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE MAINLY TO THE EAST OF THE EAST COAST TAF SITES THIS
MORNING. SEA BREEZE BOUNDARIES EARLY THIS AFTERNOON ARE EXPECTED TO
HELP GENERATE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS NEAR THE
EAST COAST TAF SITES. SO ADDED VCTS FOR THE EAST COAST TAFS. FOR
KAPF...THERE IS A SLIGHT CHANCE OF SHOWERS AHEAD OF THE
TROUGH...MAINLY BEFORE 18Z. WIND DIRECTION MAY VARY BETWEEN 160-210
DEGREES DURING THE DAY AT THE EAST COAST TAF SITES. WINDS WILL SHIFT
TO THE WEST TO NORTHWEST TONIGHT BEHIND THE BOUNDARY.
PREV DISCUSSION... /ISSUED 459 AM EDT MON APR 1 2013/
DISCUSSION...
CURRENTLY, A MID LEVEL TROUGH, ROUGHLY AT 700 MB, IS MOVING ACROSS
THE EASTERN GULF OF MEXICO. THIS HAS GENERATED A LINE OF
THUNDERSTORMS THAT IS EXPECTED TO FALL APART AS IT APPROACHES
CENTRAL FLORIDA. THIS TROUGH, ACCORDING TO THE HRRR, MAY SPARK OFF
A FEW SHOWERS OVER SOUTH FLORIDA THIS MORNING. ALSO, ANOTHER SHORT
WAVE HAS GENERATED SOME SHOWERS AND ISOLATED THUNDERSTORMS OVER
THE FLORIDA STRAITS. THESE ARE MOVING NORTH NORTHEAST. THE SHOWERS
WILL AFFECT THE SOUTHEASTERN PORTION OF THE CWA THIS MORNING. THE
QUESTION IS IF THERE WILL BE ANY THUNDERSTORMS THAT MOVE INTO THE
AREA AS WELL. THERE IS AROUND 1000 JOULES JUST ONSHORE, AROUND
HOMESTEAD AND MIAMI. SO, ALTHOUGH ORIGINAL THINKING WAS THEY WOULD
STAY OFFSHORE, MAY HAVE TO ADD A MENTION OF THUNDERSTORMS FOR THIS
AREA THIS MORNING.
AS FOR LATER TODAY, MODELS INDICATE THE TROUGH, OR REALLY, A
WEAKENING FRONT, WILL MOVE ONSHORE THE GULF COAST LATER THIS
MORNING. MODELS ARE INDICATING IT WILL NOT BE TOO ACTIVE,
CONVECTION WISE WHEN IT DOES. BUT, AS IT PROGRESS ACROSS THE
STATE, ALONG WITH DAYTIME HEATING, CONVECTION MAY BE ABLE TO
INITIATE. THE MODELS DO DIFFER GREATLY WITH HOW MUCH CAPE WILL BE
AVAILABLE. THE GFS KEEPS THE HIGHEST BOUNDARY LAYER CAPE VALUES
WELL OFFSHORE AND ONLY 500-600 JOULES OVER THE ATLANTIC COAST. THE
NAM, ON THE OTHER HAND, HAS 1200 TO 1600 JOULES OVER THE ATLANTIC
COAST, NEAT WEST PALM BEACH, AND DROPS TO 500-700 JOULES NEAR
MIAMI. NOW THE NAM MODEL SOUNDINGS HAVE 1200-1600 JOULES ALL OVER
THE ATLANTIC COAST. THEY DO SHOW A WEAK CAP FURTHER NORTH, BUT IT
IS SO WEAK, NOT THINKING IT WILL BE A REAL INHIBITOR. THERE IS
ALSO A TOUCH OF CIN TO THE NORTH AS WELL, BUT AGAIN, NOTHING THAT
REALLY SHOULD INHIBIT DEVELOPMENT. SO, WHAT WILL INHIBIT THEIR
DEVELOPMENT. WELL, MODELS DO SHOW THAT THE CAPE WILL BE PUSHING
OFF TO THE EAST, AHEAD OF THE TROUGH. SO, WE MAY BE LACKING THE
LIFTING MECHANISM. IT MAY ARRIVE WELL AFTER THE CAPE HAS PUSHED
OFF SHORE. SO, HAVE KEPT CHC POPS AND SLIGHT CHC TSTMS, BUT HAVE
BROADENED THE COVERAGE OF TSTMS THIS AFTERNOON.
BEHIND THE TROUGH TODAY, HIGH PRESSURE WILL BE BUILDING IN FAIRLY
QUICK. THIS WILL BRING QUIET WEATHER BACK TO SOUTH FLORIDA FOR A
FEW DAYS.
FOR FRIDAY AND THE WEEKEND, A LOW PRESSURE SYSTEM WILL DEVELOP
OVER THE WESTERN GULF AND MOVE OVER THE FLORIDA PANHANDLE THURSDAY
NIGHT/FRIDAY MORNING. A COLD FRONT WILL MOVE THROUGH SOUTH FLORIDA
FRIDAY. THIS SYSTEM WILL BRING OUR NEXT CHANCE FOR RAIN AND
POSSIBLY A THUNDERSTORM. MODELS ARE IN PRETTY GOOD AGREEMENT WITH
THE STRENGTH, POSITION, AND TIMING OF THIS SYSTEM. GIVEN THIS,
HAVE A HIGH CHC POP IN THE FORECAST FOR FRIDAY. BEHIND THE FRONT,
HIGH PRESSURE WILL BUILD IN ONCE AGAIN. TEMPERATURES WILL NOT BE
MUCH COOLER, ONLY A FEW DEGREES. THIS HIGH PRESSURE WILL LAST FOR
THE REMAINDER OF THE EXTENDED FORECAST.
MARINE...
WINDS AHEAD OF A WEAK FRONT/TROUGH WILL PICK UP OUT OF THE SOUTH
TO BETWEEN 13 AND 19 KTS OVER THE ATLANTIC WATERS. THEY SHOULD
REMAIN BELOW 10 KTS OVER THE GULF WATERS. THE HIGHER WIND SPEEDS
OVER THE ATLANTIC WATERS HAS PROMPTED A SMALL CRAFT SHOULD
EXERCISE CAUTION STATEMENT FOR THIS AFTERNOON. SEAS TODAY WILL BE
SUBSIDING SOMEWHAT, EVEN WITH THE WINDS, AND ARE EXPECTED TO BE 1
TO 3 FEET BY TOMORROW IN THE ATLANTIC WATERS. THE GULF WATERS WILL
BE AROUND 1 FOOT FOR THE NEXT COUPLE OF DAYS. HIGH PRESSURE WILL
BUILD IN BEGINNING TONIGHT. THIS WILL CAUSE WINDS TO WEAKEN SOME
TONIGHT TO 7-10 KTS OVER THE ATLANTIC AND SHIFT THEM OUT OF THE
NORTH TOMORROW.
FIRE WEATHER...
THE MAIN FIRE WEATHER CONCERN TODAY ARE THE SHIFTING WINDS. AN
APPROACHING FRONT/TROUGH WILL CAUSE WINDS TO PICK UP SOME TODAY TO
10 TO 15 MPH OVER GLADES, HENDRY, AND INTERIOR COLLIER COUNTIES.
THEY WILL BEGIN OUT OF THE SOUTHEAST, BUT TURN THROUGH THE DAY TO
THE SOUTH, THEN SOUTHWEST BY EARLY AFTERNOON. BY THIS EVENING,
THEY WILL BECOME WESTERLY BETWEEN 5 AND 10 MPH. ALONG WITH THIS
WIND SHIFT, WILL BE THE CHANCE FOR SOME RAIN SHOWERS AND A SLIGHT
CHANCE FOR A THUNDERSTORM. THE CHANCES INCREASE AS YOU GO EASTWARD
ACROSS SOUTH FLORIDA. IN THE INTERIOR PORTION OF THE AREA, THE
DIVIDING LINE FOR THE CHANCE OF AND THUNDERSTORMS IS A DIFFICULT
ONE AT BEST. SO, AREAS WEST OF THE FORECASTED AREA, SHOULD REMAIN
AWARE OF THE POSSIBILITY THAT THE FORECAST COULD CHANGE TO INCLUDE
THEM AS THE TROUGH GETS CLOSER. ONE THE OTHER HAND, IT COULD ALSO
BE PUSHED FURTHER EAST. THERE IS JUST GREAT UNCERTAINTY WITH THE
CONVECTIVE DEVELOPMENT TODAY.
BEHIND THE TROUGH, HIGH PRESSURE WILL BUILD IN THROUGH THURSDAY,
BRINGING QUIET WEATHER BACK TO SOUTH FLORIDA.
PREV DISCUSSION... /ISSUED 241 AM EDT MON APR 1 2013/
AVIATION...
ISOLATED SHOWERS WERE MOVING ACROSS THE ATLANTIC WATERS AND NEAR
KFLL AND FXE. ANOTHER AREA OF SHOWERS AND EMBEDDED THUNDERSTORMS
WERE MOVING JUST SOUTH OF THE KEYS. THIS AREA OF SHOWERS AND
STORMS WILL CONTINUE TO MOVE NORTHWARD OVERNIGHT...AND COULD GET
NEAR KTMB AND KMIA IN THE NEXT FEW HOURS IF THEY HOLD TOGETHER. A
SHORTWAVE TROUGH MOVING ACROSS THE EASTERN GULF WAS FORCING
SHOWERS AND THUNDERSTORMS TO DEVELOP WEST OF TAMPA. THE HRRR
KEEPS THIS LINE TOGETHER AND MOVES IT TOWARDS KAPF AROUND 16Z.
OTHER SHOWERS OR STORMS COULD ALSO BEGIN DEVELOPING ON THE EAST
COAST SEA BREEZE AROUND THIS TIME. THE WIND DIRECTION IS ALSO
TRICKY TODAY AS THE BOUNDARY LAYER WINDS SHIFT TO THE SOUTHWEST
AHEAD OF THE TROUGH AND WEAK COLD FRONT. SO THE WINDS MAY SHIFT TO
THE SOUTHWEST FOR A TIME LATE IN THE MORNING BEFORE THE EAST COAST
SEA BREEZE BOUNDARY TRIES TO PUSH THE WINDS BACK TO THE SOUTH OR
SOUTHEAST. BY 00Z...SOUTHWESTERLY FLOW IS EXPECTED TO
PREVAIL...WITH WEST TO NORTHWESTERLY FLOW BEHIND THE SURFACE
TROUGH AFTER 02-04Z. SO FOR THE TAFS...KEPT VCSH FOR NOW...BUT
MAY NEED TO ADD VCTS. MVFR CONDITIONS ARE POSSIBLE NEAR ANY
SHOWERS OR STORMS THAT FORM.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 65 81 67 81 / 20 10 - 10
FORT LAUDERDALE 68 84 71 83 / 20 10 - 10
MIAMI 68 85 69 82 / 20 10 - 10
NAPLES 65 83 64 85 / 10 10 - 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
350 PM EDT MON APR 1 2013
...BRIEF DRY PERIOD BEFORE RAIN RETURNS MID WEEK...
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
LATEST SURFACE ANALYSIS SHOWS SEMI PERMANENT SURFACE TROUGH FROM
JUST SOUTH OF ATHENS THROUGH COLUMBUS. ALONG AND SOUTH OF THIS
FEATURE MOISTURE SURFACE CONVERGENCE HAS RESULTED IN SCATTERED TO
BROKEN CU DEVELOPMENT BUT SHOWER ACTIVITY HAS REMAINED OUTSIDE OF
THE FORECAST AREA. FURTHER NORTH...SURFACE FRONT CONTINUES TO SAG
INTO NORTH GA WITH MOISTURE POOLING ALONG ITS LEADING EDGE AS WELL
AND ADDITIONAL CLOUD DEVELOPMENT THE RESULT.
THIS SHOULD REMAIN JUST CLOUDS WITH NO PRECIP FOR THIS EVENING AS
MAIN FOCUS WILL BE ON SOUTHERN TROUGH AND IT AFFECTS ON CENTRAL
GEORGIA. LOOKING AT THE LATEST RAP ANALYSIS OF CAPE IN THIS
VICINITY AND WE SEE 500 J/KG TO 1000 J/KG OF AVAILABLE
ENERGY...SLIGHTLY HIGHER THAN MODEL PROJECTIONS. STILL LOOKING AT
500MN TEMPS IN THE VERY COLD RANGE OF -17C IN THIS AREA SO ANY
SUSTAINED UPDRAFTS WILL BE CAPABLE OF PRODUCING LARGE HAIL.
ACTIVITY WILL SHIFT EAST QUICKLY THIS EVENING WITH CLEARING
CONDITIONS TAKING PLACE. STILL SOME GRADIENT IN PLACE ACROSS THE
AREA WHICH WILL PREVENT OPTIMUM RADIATIONAL COOLING CONDITIONS.
WENT WITH A MAV/MET BLEND FOR THE OVERNIGHT TEMPS WHICH WILL BE
TRICKY TO THE SOUTH BASED ON HOW FAST CLOUDS CLEAR.
SURFACE FRONT LOOKS TO STALL ACROSS NORTH GEORGIA TUESDAY AND
IMPULSES OF ENERGY BEGIN TO ROUND PERIPHERY OF EAST COAST TROUGH.
THIS SHOULD ALLOW A FEW LIGHT SHOWERS TO DEVELOP ACROSS EXTREME
NORTH GEORGIA AND HAVE INCLUDED IN THIS GRID PACKAGE. AS HIGH
BRIDGES ACROSS THROUGH TUESDAY NIGHT...MAY SEE FRONT SAG FURTHER
SOUTH AND TAKE 20 POPS ALONG WITH IT INTO THE REMAINDER OF NORTH
GEORGIA.
DEESE
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
MAIN CONCERN FOR THE EXTENDED REMAINS THE SYSTEM MOVING THROUGH
THE STATE ON WEDNESDAY INTO THE END OF THE WORK WEEK.
DISCREPANCIES STILL REMAIN BETWEEN THE EURO AND GFS AS FAR AS
TIMING OF THE SYSTEM LEAVING THE CWA. THE 12Z MODELS ARE
STRIKINGLY SIMILAR TO THEIR OOZ COUNTERPARTS. AS SUCH...WAS NOT
ABLE TO NAIL DOWN AN ACCURATE END TO THE RAIN THIS WEEK. ACCORDING
TO HPC MODEL DISCUSSIONS THE EURO IS AN OUTLIER...MOVING THE
SYSTEM FURTHER SOUTH AND IS SLOWER. THAT SAID THEY DECIDED TO WITH
A BLEND BETWEEN THE 00Z EURO AND THE 06Z GEFS. WITH THIS MUCH
UNCERTAINTY DECIDED TO ONLY CHANGE THE COVERAGE OF THUNDER ON
WEDNESDAY AND LEAVE THE REST OF THE FORECAST ALONE. DID LOWER
TEMPS ON THURSDAY AS A PSEUDO WEDGE BUILDS IN. CLOUDS AND RAIN IN
ASSOCIATION WITH THIS WEDGE SHOULD HELP TO KEEP TEMPS LOW. HAVE
INCLUDED PREVIOUS EXTENDED BELOW/
ARG
&&
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... POTENTIAL FOR A HEAVY
RAIN/SEVERE WEATHER EVENT SETTING UP IN THE THURSDAY TO THURSDAY
NIGHT TIME FRAME. MODELS SIMILAR WITH SPREADING DEEPER MOISTURE
INTO THE AREA LATE WEDNESDAY BUT THE MAIN PRECIP PERIOD LOOKS TO
BE WEDNESDAY NIGHT THRU THURSDAY NIGHT. AN OVERRUNNING PATTERN
WILL SET LATE WEDNESDAY/WEDNESDAY NIGHT WITH MODELS DEVELOPING A
WARM FRONT ALONG THE GULF COAST. SURFACE LOW PRESSURE DEVELOPS
OVER THE WESTERN GULF AND MOVES TO THE WESTERN FL PANHANDLE LATE
THURSDAY AND THEN ACROSS CENTRAL TO S GA THURSDAY NIGHT/FRIDAY.
THE GFS IS FASTER WITH THIS PROGRESSION THAN THE EUROPEAN. THIS
TRACK COULD MOVE THE WARM FRONT INTO THE SE CWA AND GIVE POTENTIAL
FOR SEVERE THUNDERSTORMS MAINLY THURSDAY NIGHT. IT WILL ALSO GIVE
POTENTIAL FOR HEAVY RAIN ACROSS A LARGE PORTION OF EAST GEORGIA
AND MODELS IN GENERAL ARE LESS GUN-OH WITH PRECIP AMOUNTS WITH A
LARGE AREA OF 1-2 INCHES FORECAST. THE UPPER TROUGH MOVES ACROSS
THE AREA ON FRIDAY AND THE GFS IS FASTER WITH THIS PROGRESSION
THAN THE EUROPEAN. THE AIRMASS DRIES OUT FOR SATURDAY AND MOSTLY
LIKELY SUNDAY WITH THE EUROPEAN INDICATING SOME MOISTURE
ASSOCIATED WITH A SHORT WAVE ON SUNDAY...MOST SO FOR N GA. FOR NOW
WILL KEEP THINGS DRY AND MONITOR THE PROGRESSION. A SHORT WAVE
RIDGE BUILDS FOR MONDAY WITH THE EUROPEAN CONTINUING TO SHOW MORE
MOISTURE SKIRTING OVER N GA THAN THE GFS.
BDL
AVIATION...
18Z UPDATE...
VFR FORECAST IN STORE AS MAIN CLOUD SHIELD HAS SLIPPED TO THE
SOUTH OF THE TERMINALS. WILL BE WATCHING SECONDARY AREA OF CLOUDS
DEVELOPING OVER EXTREME NORTH GA IN ENHANCED MOISTURE ZONE BUT
JUST PLAYING AS FEW050 FOR NOW. OTHERWISE...STILL UNCERTAINTY
WITH WIND SHIFT POTENTIAL MID MORNING TUESDAY WITH NW VS NE STILL
IN QUESTION FOR ATL. WENT WITH CONSENSUS OF NW FOR NOW WHICH
AGREES WITH PARTNERS AND CONSENSUS.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM ON WIND SHIFT.
HIGH ON REMAINING ELEMENTS.
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 42 69 41 64 / 10 10 20 20
ATLANTA 47 67 44 64 / 5 5 20 20
BLAIRSVILLE 37 58 35 63 / 10 10 20 20
CARTERSVILLE 41 65 40 64 / 5 10 20 20
COLUMBUS 51 75 50 70 / 5 5 5 30
GAINESVILLE 44 65 43 61 / 10 10 20 20
MACON 45 75 44 69 / 5 5 5 30
ROME 38 65 38 64 / 5 10 20 20
PEACHTREE CITY 40 70 42 65 / 5 5 20 30
VIDALIA 55 76 51 74 / 20 0 5 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DEESE
LONG TERM....ARG
AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS WICHITA KS
1230 PM CDT MON APR 1 2013
.UPDATE...
ISSUED AT 1229 PM CDT MON APR 1 2013
PUT OUT ANOTHER UPDATE TO ADD LIGHT SNOW AS A PRECIP TYPE BASED ON
LATEST REPORTS. HOWEVER THE BIGGER REASON FOR THE UPDATE WAS TO DROP
HIGHS TODAY SEVERAL DEGREES.
ISENTROPIC LIFT NORTH OF THE SURFACE COLD FRONT HAS RESULTED IN
NUMEROUS RAIN/SNOW SHOWERS ACROSS MOST OF SOUTH CENTRAL KS. THIS
ACTIVITY SHOULD CONTINUE TRACKING OFF TO THE EAST-SOUTHEAST THIS
AFTERNOON. WITH WARM GROUND TEMPS...NO ACCUMULATION IS EXPECTED.
THE INCREASED CLOUD COVER WILL COMBINE WITH TEMPS WET-BULBING DOWN
TO KEEP TEMPS FROM CLIMBING MUCH THIS AFTERNOON. SO WENT AHEAD AND
DROPPED HIGHS SEVERAL DEGREES.
UPDATE ISSUED AT 1013 AM CDT MON APR 1 2013
SENT OUT A QUICK UPDATE TO KEEP UP WITH CURRENT PRECIP TRENDS.
ISENTROPIC LIFT ALONG THE 305K SURFACE HAS RESULTED IN PRECIP
EXPANDING OVER SW PORTIONS OF THE FORECAST AREA. THIS ACTIVITY
SHOULD CONTINUE TO PUSH EAST LATE THIS MORNING INTO THE EARLY
AFTERNOON HOURS. A COUPLE RUMBLES OF THUNDER MAY MIX WITH THE
SHOWERS.
LAWSON
&&
.SYNOPSIS...
ISSUED AT 332 AM CDT MON APR 1 2013
A POTENT DISTURBANCE IS PLUNGING SOUTHWARD INTO THE GREAT LAKES
REGION...CAUSING A COLD FRONT TO DIVE SOUTHWARD ACROSS THE CENTRAL
PLAINS. THE COLD FRONT HAS MADE IT HALF WAY THROUGH KANSAS AS OF
THIS ISSUANCE AND WILL CONTINUE TO MOVE SOUTHWARD THROUGH OKLAHOMA
DURING THE DAY. WINDS ARE GUSTY BEHIND THE FRONT WITH LOW TO MID
LEVEL CLOUDS. LOOKING WEST...ANOTHER DISTURBANCE IS LOCATED OVER
MID-CALIFORNIA/NEVADA/UTAH. THIS WILL BE THE WEATHER MAKER FOR THE
FIRST PART OF THE WEEK.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 332 AM CDT MON APR 1 2013
THIS PERIOD WILL BE RAINY OFF AND ON AND COOLER FOR MUCH OF SOUTHERN
KANSAS. THE LATEST GUIDANCE...NAM/GFS/ECMWF AND HRRR INDICATE
PRECIPITATION DEVELOPING ACROSS SOUTH CENTRAL KANSAS AROUND MID
AFTERNOON TODAY BEFORE SPREADING EAST ACROSS SOUTHERN KANSAS THROUGH
THE DAY AND OVERNIGHT. PRECIPITATION WILL DEVELOP NEAR THE 850MB
FRONT. THE UPPER LEVEL WAVE OVER THE WEST WILL CONTINUE TO MOVE
TOWARDS THE AREA...ENHANCING UPPER LEVEL SUPPORT. THE 850MB FRONT
WILL REMAIN STATIONARY...KEEPING THE PRECIPITATION CHANCES THROUGH
WEDNESDAY. NOT EXPECTING THUNDER WITH THIS EVENT WITH VERY LOW
MUCAPE VALUES...BUT CANNOT RULE OUT AN ISOLATED LIGHTNING STRIKE.
THIS PERIOD WILL REMAIN COOLER...AS THE COLD FRONT USHERED IN
UNSEASONABLY COOL AIR. WITH COLD AIR ADVECTION...CLOUDY SKIES AND
RAIN...TEMPERATURES WILL BE 10 TO 20 DEGREES BELOW NORMAL. TUESDAY
LOOKS TO BE THE COOLEST DAY WITH CLOUD COVER AND RAIN.
BILLINGS
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 332 AM CDT MON APR 1 2013
BY THURSDAY THE UPPER LEVEL DISTURBANCE THAT WILL IMPACT THE AREA
FOR THE FIRST HALF OF THE FORECAST WILL FINALLY BE ON ITS WAY EAST.
SURFACE HIGH PRESSURE WILL MOVE OVERHEAD THURSDAY WITH CLEARING
SKIES IN THE SUBSIDENCE ZONE OF THE UPPER WAVE. THIS WILL ALLOW
TEMPERATURES TO WARM BACK INTO THE UPPER 50S AND LOW 60S.
TEMPERATURES WILL CONTINUE TO INCREASE FOR FRIDAY AND SATURDAY AHEAD
OF THE NEXT SYSTEM. LEE CYCLOGENESIS WILL DEEPEN AHEAD OF THE NEXT
WAVE...WITH STRONG WARM AIR ADVECTION AND MIXING...TEMPS WILL REACH
BACK INTO THE 60S AND 70S. THE NEXT DISTURBANCE WILL MOVE ACROSS
THE NORTHERN PLAINS...DRAGGING A COLD FRONT ACROSS THE REGION. THE
MAIN LIFT ASSOCIATED WITH THIS FRONT WILL BE ACROSS THE NORTHERN
PLAINS...SO NOT EXPECTING MUCH IN THE WAY OF PRECIPITATION ALONG THE
FRONTAL BOUNDARY AND HAVE LEFT THE FORECAST DRY FOR SATURDAY AND
SUNDAY. TEMPERATURES BEHIND THE FRONT WILL ONLY DECREASE SLIGHTLY.
ANOTHER WAVE WILL APPROACH FOR THE VERY END OF THE FORECAST AND
PRECIPITATION MAY RETURN FOR SUNDAY AND INTO THE EARLY PART OF NEXT
WEEK. WILL CONTINUE TO WATCH THIS PERIOD AS THE FORECAST EVOLVES AS
THE TIME PERIOD NEARS.
BILLINGS
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1229 PM CDT MON APR 1 2013
MAIN AVIATION FORECAST CONCERNS WILL PRECIP THIS AFTERNOON ALONG
WITH LOWERING CIGS TONIGHT.
THE PRECIP AFFECTING SOUTH CENTRAL KS WILL CONTINUE SLOWLY TRACKING
OFF TO THE SOUTHEAST THIS AFTERNOON WITH MAINLY KICT BEING AFFECTED.
A RAIN-SNOW MIX WILL BE THE MAIN PRECIP TYPE. THERE SHOULD BE A
BREAK IN THE PRECIP LATE THIS AFTERNOON/EARLY THIS EVENING BEFORE
ISENTROPIC LIFT GETS CRANKED UP AGAIN AFTER DARK. HOWEVER FOR THIS
EVENING FEEL THAT THE BULK OF THE PRECIP WILL BE SOUTH OF THE KS-OK
BORDER WITH KICT BEING ON THE NORTHERN FRINGES OF THE PRECIP. IN
ADDITION...CIGS WILL START TO LOWER TOWARD SUNRISE ACROSS SOUTH
CENTRAL KS WITH KICT POSSIBLY GETTING INTO SOME MVFR CONDITIONS BY
12Z.
LAWSON
&&
.FIRE WEATHER...
ISSUED AT 332 AM CDT MON APR 1 2013
VERY LITTLE IN THE WAY OF FIRE CONCERN FOR MUCH OF THE FORECAST.
LIGHT WINDS AND PRECIPITATION WILL KEEP GRASSLAND FIRE DANGER LOW.
WITH STRONGER WINDS AND WARMER TEMPERATURES ON FRIDAY...GRASSLAND
FIRE DANGER WILL BE VERY HIGH.
BILLINGS
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 45 35 43 35 / 80 60 50 30
HUTCHINSON 42 33 45 32 / 50 40 40 20
NEWTON 43 32 43 31 / 50 30 30 20
ELDORADO 45 33 44 33 / 80 40 40 20
WINFIELD-KWLD 49 36 42 36 / 90 70 70 40
RUSSELL 43 30 48 30 / 10 30 20 10
GREAT BEND 42 31 46 31 / 20 30 30 20
SALINA 43 31 50 33 / 10 20 10 10
MCPHERSON 42 32 46 32 / 20 30 20 10
COFFEYVILLE 52 37 44 36 / 70 60 70 40
CHANUTE 48 34 44 34 / 40 30 30 10
IOLA 47 33 45 33 / 20 20 20 10
PARSONS-KPPF 50 35 44 35 / 60 50 50 30
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GAYLORD MI
154 PM EDT MON APR 1 2013
.SYNOPSIS...
ISSUED AT 422 AM EDT MON APR 1 2013
A SYSTEM IN QUEBEC IS BRINGING COLD AIR AND NORTHWEST WINDS TO THE
STATE TODAY. THE COLDER AIR IS PRODUCING LAKE EFFECT SNOW SHOWERS
WHICH WILL PERSIST OVER NORTHERN MICHIGAN THROUGH TUESDAY. THE MOST
PERSISTENT SNOW SHOWERS WITH THE BEST CHANCE OF ACCUMULATION WILL BE
IN THE TYPICAL SNOW BELTS OF NORTHWEST LOWER AND EAST UPPER
MICHIGAN.
&&
.UPDATE...
ISSUED AT 153 PM EDT MON APR 1 2013
CURRENT FORECAST IS IN LINE. LAKE EFFECT SNOWS CONTINUE OVER NRN
MI...AS SFC-850MB WINDS LINGER FROM THE NW AND 850MB TEMPS REMAIN
ARND -16C.
UPDATE ISSUED AT 951 AM EDT MON APR 1 2013
THE STORM SYSTEM WHICH SWEPT ACROSS THE GREAT LAKES THIS WEEKEND...
HAS PUSHED EAST OF THE STATE AND WILL CONTINUE TO LIFT INTO QUEBEC
THROUGH TUESDAY. COLD 850MB TEMPS...NORTHWEST WINDS AND LAKE EFFECT
SNOWS HAD ALREADY BEGUN TO FILTER INTO NRN MI EARLIER THIS MORNING.
850MB TEMPS DROPPED FROM AROUND 0C SUNDAY AFTERNOON TO ARND -16C BY
12Z THIS MORNING.
AS FOR THE REST OF THE AFTN...THE PARAMETERS WHICH ARE CURRENTLY
GENERATING LAKE INDUCED SNOWS OVER THE WRN LAKES...ARE NOT EXPECTED
TO CHANGE MUCH THROUGH 21Z. 850MB TEMPS WILL LINGER AROUND -16C AS
THE AXIS OF THE SFC AND 500MB FEATURES PUSH FURTHER EAST OF THE REGION
THIS AFTERNOON. SFC-850MB WINDS WOBBLE DURING THE AFTN...THOUGH
REMAIN GENERALLY NW (300-320) WHILE INVERSION HEIGHTS LINGER AROUND
5K FT. OVERALL EXPECT WIDESPREAD LAKE SNOWS TO CONT OVER THE WRN
LAKES THROUGH THE AFTN...THOUGH WITH THE HIGH SUN ANGLE...EXPECT
DOMINATE SNOW BANDS TO BECOME A LEAST SLIGHTLY DISRUPTED THROUGH THE
REST OF THE MORNING. OVERALL WILL KEEP CONT TO MENTION LAKE SNOWS
THROUGH THE AFTN. WILL MENTION UP TO 2 INCHES OF SNOW POSSIBLE IN
FAVORED SNOW BELTS...AND WILL EXTEND HEADLINES THRU THE AFTN.
UPDATE ISSUED AT 708 AM EDT MON APR 1 2013
CHANGES THIS HOUR: ADDITIONAL /UPWARD/ ADJUSTMENTS TO SNOWFALL AS
A BAND OF NEARLY 5 INCHES HAS OCCURRED OVER EXTREME SW OTSEGO
COUNTY AND NW CRAWFORD COUNTY. BANDING IS MAKING ITS EXPECTED
SHIFT EAST...AND IS BEGINNING TO BECOME A LITTLE MORE DIFFUSE.
EXPECT WE/VE GOT 2-3 MORE HOURS OF DECENT ACCUMS BEFORE THINGS
WIND DOWN. ADVISORY CONTINUES TO LOOK GOOD AND WILL MAKE NO
CHANGES TO THIS.
UPDATE ISSUED AT 519 AM EDT MON APR 1 2013
CHANGES THIS HOUR: BAND HESITATED LONG ENOUGH FOR ME...AND HAVE
ISSUED A WINTER WEATHER ADVISORY FOR 4 OF THE BIG 5 /EXCLUDED
KALKASKA/ THROUGH NOON. RADAR ESTIMATES HAVE REACHED 2-3" IN
SPOTS...WITH BIG FLUFFY FLAKES FALLING HERE AT THE OFFICE
INDICATING 20:1 RATIOS LOOK GOOD. WINDS AMPLE TO BLOW THIS SNOW
AROUND AS WELL. EXPECT 2-4 OVER THE NEXT FEW HOURS AS BAND STARTS
TO EDGE EAST FROM ITS CURRENT LOCATION...BEFORE LIKELY BREAKING UP
BY LATE MORNING.
NO OTHER CHANGES ATTM.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 422 AM EDT MON APR 1 2013
HIGH IMPACT WEATHER POTENTIAL: GALE FORCE WIND GUSTS POSSIBLE ALL
MARINE WATERS THROUGH TODAY. SNOW/BLOWING SNOW WILL BRING SOME
SLICK TRAVEL AND REDUCED VISIBILITIES TO THE SNOWBELTS OF EASTERN
UPPER/NORTHERN LOWER...WITH SNOW SHOWERS REACHING ALL OTHER LOCALES
AS WELL.
OVERVIEW: WISHING THE EARLY MORNING WATER VAPOR IMAGERY WAS AN APRIL
FOOLS JOKE THIS MORNING AS IMPRESSIVE TROUGH CARVES ITSELF OUT OVER
THE GREAT LAKES REGION. PICKLE LAKE /ONTARIO/ 00Z RAOB SHOWS -42C AT
H5...-25C AT H7 AND -20C AT H8...AN ARCTIC AIRMASS INDEED WITH SURFACE
TEMPS UPSTREAM OF THE GREAT LAKES IN THE LOWER TEENS AND DEWPOINTS
FALLING TO NEAR ZERO. WITH SUBSTANTIAL DOWNSTREAM BLOCKING IN PLACE
FROM GREENLAND SOUTH AND EAST...THE DEVELOPING LONGWAVE TROUGH
OVERHEAD WILL BE IN NO HURRY TO DEPART...WITH ITS IMPACTS DOMINATING
THE SHORT TERM PORTION OF THE FORECAST.
THROUGH DAYBREAK: APX WSR-88D SHOWING LAKE EFFECT SNOW GETTING IT/S
ACT TOGETHER OVER NORTHERN LOWER...WITH PRIMARY BAND FROM ACB-GOV
STRENGTHENING WITH GOOD LAKE SUPERIOR CONNECTION. EXPECT THIS TREND
TO CONTINUE THROUGH DAYBREAK WITH AN INCH OR TWO OF SNOW POSSIBLE
OVER THE BIG 5 OF NW LOWER. WILL COVER THIS BAND WITH AN SPS FOR A
QUICK 1-2 INCHES WHICH WILL LIKELY IMPACT THE MONDAY MORNING
COMMUTE.
WINDS REMAIN QUITE BRISK AS 6MB/6HR PRESSURE RISE CENTER OVER
NORTHERN LAKE SUPERIOR SLIDES SOUTH AND EAST...WITH 15-25 MPH WINDS
THROUGHOUT NORTHERN MICHIGAN...GUSTING AS HIGH AS 35 MPH NEAR THE
COASTS.
TODAY: WITH THE CORE OF THE H5 LOW PUSHING FROM JUST NORTH OF THE
SOO EARLY THIS MORNING TO SOUTHWESTERN QUEBEC BY THSI EVENING...OUR
FLOW ALOFT WILL BACK SLIGHTLY AS THE COLDEST AIR ALOFT MAKES ITS
CLOSEST APPROACH. T8 AROUND -17C WITH WHAT LOOKS TO BE ROBUST
LLEVEL MOISTURE /SEE FOG PRODUCT IMAGERY SHOWING ALL KINDS OF
MOISTURE JUST WEST OF THE H5 LOW CENTER /AND THUS...OVERHEAD
TODAY/. THIS SPELLS CONTINUED LAKE EFFECT SNOW SHOWERS UNDER STRONG
NW WINDS. ALL HIGH RESOLUTION GUIDANCE CONTINUES TO SHOW A DOMINANT
BAND TO START THE DAY...WITH THE HRRR LOOKING TO CAPTURE IT/S
LOCATION BEST /FURTHER WEST THAN THE RAP AND LOCAL WRF/. GIVEN THAT
WE ALREADY HAVE A BAND OF THIS NATURE...SEE NO REASON TO DISAGREE
WITH THE GUDIANCE SUGGESTION...WHICH SHOWS THIS BAND STARTING THE
DAY CENTERED FROM CVX-ACB-GOV PUSHING EAST GIVEN THE AFOREMENTIONED
BACKING FLOW...WITH SOMEWHAT LIGHTER SHSN SURROUNDING IT. THE BAND
LOOKS TO BE QUITE MOBILE THROUGH THE MORNING BEFORE CAPE/SHEAR
NOMOGRAM SUGGESTS THAT BY LATE MORNING IT WIL BEGIN TO BREAK UP AS
OVERLAND INSTABILITY STRENGTHENS. THIS BACKING FLOW SHOULD HELP GET
WESTERN CHIPPEWA/MACKINAC BACK INTO THE ACTION DURING THE DAY AS
WELL.
SNOWFALL: MOBILE SNOWBAND WILL KEEP A LID ON SNOW AMOUNTS...BUT
COULD SEE 1-3" FOR THE DAY TODAY OVER THE NW SNOWBELTS...WITH MOST
OF THIS FALLING BEFORE ACTIVITY BECOMES MORE CELLULAR THIS
AFTERNOON.
WHILE WE LOSE HELP FROM ANY ISALLOBARIC COMPONENT TO THE LLEVEL
WINDS TODAY...H9 WINDS 25-30KTS AND AMPLE LLEVEL MIXING SUGGEST
WINDS 15-25 MPH WINDS WITH GUSTS WELL INTO THE 30S...PARTICULARLY
NEAR THE LAKESHORES AND OVER EASTERN UPPER.
TEMPS WILL BE VERY SLOW TO CLIMB WITH T9 AROUND -10C SUGGESTING MID
20S /SOME 20F BELOW NORMAL/ WILL BE ABOUT ALL WE CAN MUSTER. WITH
THE STRONG WINDS...WIND CHILLS WILL REMAIN IN THE TEENS THROUGH THE
DAY.
HEADLINES: WILL GO AHEAD AND DROP WINTER WEATHER ADVISORY FOR
CHIPPEWA GIVEN LOCATION OF SNOWFALL ACTIVITY WELL WEST OF COUNTY
WITH ACCUMS THUS FAR NOT SUFFICIENT TO WARRANT THE HEADLINE.
AS DISCUSSED ABOVE...HEAVIEST SNOW IS NOW OVER THE BIG 5 IN NW
LOWER...AND WILL MONITOR FOR POTENTIAL HEADLINE THROUGH
DAYBREAK...ALTHOUGH EXPECTATION IS THAT THE BAND WILL BEGIN TO
MOVE...REDUCING THE THREAT OF SIGNIFICANT ACCUMS.
TONIGHT: SYNOPTIC MOISTURE BEGINS TO SLOWLY ERODE WITH TEMPS ALOFT
STEADY OR JUST SLIGHTLY WARING UNDER A FAIRLY STEADY 300-310 FLOW
REGIME. SOME RESIDUAL LAND-BASED CAPE CONTINUES THROUGH THE
OVERNIGHT WHICH MAY NOT FULLY ALLOW THE LAKE EFFECT TO RE-SOLIDIFY
INTO BANDS. SHSN WILL CERTAINLY CONTINUE...HOWEVER...WITH
ADDITIONAL LIGHT ACCUMULATIONS LIKELY. INHERITED ACCUMS OF 1-2
INCHES /PERHAPS 3 OVER WESTERN CHIPPEWA/ LOOK REASONABLE AND HAVE NO
COMPELLING REASON TO DEVIATE SIGNIFICANTLY.
CLOUDS WILL LIKELY KEEP TEMPERATURES FROM FALLING ALL THAT FAR...
GENERALLY IN THE UPPER TEENS TO AROUND 20.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 422 AM EDT MON APR 1 2013
TUESDAY...AS THE SFC HIGH BEGINS TO MOVE INTO THE REGION, THE 850 MB
TEMPERATURES BEGIN TO WARM SLIGHTLY, JUST ENOUGH THAT WE MAY LOSE
THE INSTABILITY NEEDED FOR THE LES. THE MOISTURE IN THE 850-700 MB
LAYER FALLS OFF TO BELOW 60% ON ALL THE MODELS SO WOULD EXPECT LIGHT
SNOW AND FLURRIES. ALTHOUGH WILL HAVE LIKELY POPS SINCE MEASURABLE
SNOW IS EXPECTED FROM THIS PATTERN IN THE MORNING. BY THE AFTERNOON,
THE MOISTURE CONTINUES TO FALL OFF IN THE 850-700 MB LAYER. THE ONE
THING THAT I HAVE NOTICED ABOUT THESE LATE SEASON LES EVENTS IS THAT
IT HAS BECOME HARD FOR THE LOWER END OF THE SOUNDINGS TO SATURATE.
THIS HAS BEEN LEADING TO INVERTED V SOUNDINGS AND REALIZING LESS
SNOW THAN WE WOULD HAVE EVEN A MONTH AGO DURING THE AFTERNOON.
TUESDAY NIGHT...AS THE RIDGE BUILDS INTO THE REGION, THE DRIER AIR
REALLY BEGINS TO OVERWHELM THE REGION, SHUTTING OFF MOST OF THE SNOW
LEAVING ONLY CHANCE POPS IN THE EVENING IN E UPPER, WHILE N LOWER
WILL BE DRY ENOUGH TO NOT HAVE ANY SNOW.
WEDNESDAY...HIGH PRESSURE AT THE SFC AND 500 MB RIDGE MOVES THROUGH
THE REGION SO THAT WE WILL REMAIN DRY FOR THE DAY. OVERNIGHT, A COLD
FRONT AND 500 MB SHORTWAVE TROUGH MOVE INTO THE REGION. THE GFS IS A
LITTLE FASTER THAN THE ECMWF AND NAM. WILL HOLD OFF THE SNOW BY
ALLOWING IT TO JUST TOUCH E UPPER BY 12Z.
EXTENDED (THURSDAY THROUGH SUNDAY)...THURSDAY, THE MODELS DRY THINGS
OUT WITH THE FRONTAL PASSAGE DURING THE DAY. SO WILL HAVE CHANCE
POPS WITH A MIX OF THE RAIN AND SNOW IN E UPPER AND JUST RAIN IN N
LOWER. WITH THE SFC TEMPERATURES IN THE 40S, WOULD NOT BE SURPRISED
IF THIS TURNS OUT TO BE FLURRIES AND SPRINKLES. FRIDAY, THE HIGH
BUILDS INTO THE UPPER GREAT LAKES REGION AND DRIES THINGS OUT AGAIN.
SO DRY WEATHER WILL BE EXPECTED. SATURDAY, THE WARM FRONT WILL BE
MOVING INTO THE REGION. THE ECMWF HAS THE WARM AIR INTO E UPPER SO
THAT IT COULD BE ALL RAIN, WHILE THE GFS HAS IT PLACED A LITTLE
SOUTH. PUT THE DIVIDING LINE AT THE STRAITS SINCE THAT SEEMED TO BE
THE MIDDLE GROUND. WHICH WOULD CONTINUE THROUGH THE NIGHT AS THE
SYSTEM MOVES EAST. SUNDAY, THE LOW MOVES EAST OF THE REGION AND THE
COLD AIR MOVES BACK IN ALLOWING FOR A CHANGE OVER TO SNOW. THE GFS
DRIES THINGS OUT. WILL LEAN TOWARD THE ECMWF WHICH WOULD BE THE
PESSIMISTIC FORECAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 153 PM EDT MON APR 1 2013
MVFR CIGS WILL CONTINUE OVR NRN MI THRU THE TAF PERIOD...A RESULT
OF COLD NORTHWEST FLOW ON THE BACKSIDE OF A SYSTEM WOBBLING OVER
QUEBEC. 850MB TEMPS WILL BE COLD ENOUGH TO GENERATE LAKE SNOWS OVER
NRN MI TAF SITES INTO TUESDAY AFTN. THE MOST PERSISTENT LAKE SNOWS AND
OCCASIONAL IFR VSBYS...WILL INFLUENCE TAF SITES KPLN AND KTVC INTO
TUESDAY AFTN.
&&
.MARINE...
ISSUED AT 422 AM EDT MON APR 1 2013
UPDATE AT 708 AM...DROPPED GALE WARNINGS FOR ALL AREAS SAVE
WHITEFISH BAY AND THE COAST OF NORTHERN LAKE HURON. HIGH END SMALL
CRAFTS SHOULD SUFFICE THROUGH TODAY AND WILL NEED EXTENDING BEYOND
TONIGHT IN SUBSEQUENT UPDATES.
SUMMARY: STRONG NORTHWESTERLY WINDS TO CONTINUE THROUGH TUESDAY AS
LOW PRESSURE MOVES INTO EASTERN CANADA. HIGH PRESSURE ARRIVES BY
MIDWEEK WITH QUIETER CONDITIONS EXPECTED.
HEADLINES: MARGINAL GALES WILL BE ALLOWED TO CONTINUE ALL ZONES
THROUGH THIS EVENING. SMALL CRAFTS WILL CERTAINLY BE NEEDED BEYOND
THIS...WITH ADDITIONAL GALE FORCE GUSTS POSSIBLE AGAIN
TUESDAY...PARTICULARLY FOR NORTHWESTERLY FLOW FAVORED REGIONS.
BEYOND THIS...NEXT ROUND OF SMALL CRAFTS LOOKS LIKELY BY WEDNESDAY
NIGHT OVER LAKE MICHIGAN AS SOUTHWESTERLY WINDS STRENGTHEN AHEAD OF
NEXT APPROACHING SYSTEM.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR
MIZ015>017-019-021>023-027-028.
LH...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LHZ345-346-
349.
GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LHZ347-348.
LM...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LMZ323-341-
342-344>346.
LS...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LSZ322.
GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LSZ321.
&&
$$
UPDATE...SR
SYNOPSIS...JL
SHORT TERM...ARNOTT
LONG TERM...JL
AVIATION...SR
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
126 PM EDT MON APR 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 440 AM EDT MON APR 1 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF
CENTERED FM HUDSON BAY INTO THE GRT LKS DOWNSTREAM OF UPR RDG OVER
WRN CANADA. 00Z H5/H85 TEMPS ARE AS LO AS -42C/-20C AT THE CORE OF
THE COLDEST AIR AT YPL. CYC NNW FLOW ON THE WRN FLANK OF LO PRES
MOVING SLOWLY E INTO QUEBEC IS DRAWING THIS VERY COLD AIR SWD INTO
THE UPR LKS OVER THE RELATIVELY WARM WATERS OF LAKE SUP...WITH THE
RESULT NMRS LES BANDS AS SHOWN ON MQT RADAR. WELL DEFINED AXIS OF
COLDER CLD TOPS AS SHOWN ON IR STLT IMAGERY IS PRESENT OVER THE E
HALF OF THE LK AND ASSOCIATED WITH FAIRLY SHARP H7-3 QVECTOR CNVGC.
THIS AXIS OF DEEPER MSTR HAS CAUSED SOME ENHANCEMENT TO THE SHSN.
THE HEAVIEST BAND IS STREAMING INTO CENTRAL ALGER COUNTY/SCHOOLCRAFT
COUTY...WITH SOME RETURNS AOA 30 DBZ AT 06Z. SN UNDER THIS BAND IS
LIKELY FALLING AT THE RATE OF AT LEAST AN INCH/HR GIVEN FAVORABLE
LOCATION OF UVV MAX WITHIN DGZ AS SHOWN BY PROFILE FM LOCAL HI RES
MODEL. SINCE THE COLDER CLD TOPS ARE TENDING TO DRIFT TO THE E AND
DRIER LLVL AIR SHOWN ON THE 00Z INL RAOB IS PRESSING TO THE E...
DROPPING THE SFC DEWPT TO NEAR 7F AT IWD AT 06Z...THE INTENSITY OF
THE LES W OF MQT HAS TENDED TO DIMINISH OVER TIME PER RADAR TRENDS
EVEN THOUGH IR STLT IMAGERY INDICATES SOME LES BANDS OVER THE W HALF
OF THE LK THAT HAVE FORMED IN THE PRESENCE OF NOCTURNAL COOLING THAT
IS SO IMPORTANT TO ACHIEVE BETTER LES BAND STRUCTURE THIS TIME OF
YEAR. NW WINDS ARE STILL GUSTING AS HI AS 40 KTS AT STANNARD ROCK AS
OF 06Z...BUT PASSAGE OF PRES RISE CENTER TRAILING THE SFC LO INTO
ONTARIO E OF LK SUP HAS CAUSED A SLOW DIMINISHING TREND TO THE WINDS.
MAIN FCST CONCERNS THIS PACKAGE ARE LES TRENDS/GOIND HEADLINES.
TODAY...MODELS INDICATE UPR TROF AXIS WL DRIFT SLOWLY TO THE E. AREA
OF DEEP LYR QVECTOR CNVGC ENHANCING COMMA HEAD/COLDER CLD TOPS NOW
OVER THE E HALF OF LK SUP IS PROGGED TO DRIFT INTO ONTARIO IN THE
09Z-12Z TIME FRAME. IN CONCERT WITH THE ARRIVAL OF SOME DRYING FM
THE W...LES INTENSITY/COVERAGE SHUD DIMINISH BY SUNRISE. BUT GIVEN
PERSISTENCE OF SGNFT BAND OVER CENTRAL ALGER COUNTY INTO NRN
SCHOOLCRAFT COUNTY IN PERSISTENT NNW FLOW THRU THE EARLY MRNG
HRS...FVRBL SN/WATER RATIOS UNDER COLDEST H85 TEMPS...AND HIER RES
MODEL FCSTS THAT SHOWING FAIRLY HI QPF THRU 18Z WITH DEEPER MSTR
PERSISTING LONGEST IN THAT AREA CLOSER TO DEPARTING LO...OPTED TO
UPGRADE GOING ADVY FOR THOSE ZONES TO AN LES WARNING. OTRW...RISING
H5 HGTS/DEEP LYR QVECTOR CNVGC/SUBSIDENCE IN THE PRESENCE OF DIURNAL
HEATING THAT TENDS TO DISRUPT THE LES PROCESS IN EARLY SPRING SHOULD
CAUSE THE LES BANDS TO WEAKEN AND TRANSITION TO A MORE BLOTCHY
APPEARANCE. SLOWLY BACKING FLOW TOWARD MORE WNW BY THE LATE IN THE
DAY WL ALSO CAUSE AREA OF HEAVIER SHSN TO SHIFT. ADDITIONAL SN
AMOUNTS OVER THE W WL BE LIGHT WITH LLVL DRY AIR HAVING A MORE SGNFT
IMPACT THERE AND MODELS HINTING TOWARD A TRANSITION TO LLVL ACYC
FLOW IN THE AFTN.
TONIGHT...STEADILY RISING HGTS/DEEP LYR QVECTOR CNVGC THAT DROPS
FCST INVRN BASE TOWARD 5-6K FT OVER EVEN THE E SUG LES INTENSITY WL
BE SOMEWHAT DIMINISHED EVEN THOUGH PERSISTENT NW FLOW/H85 TEMPS IN
THE -16 TO -17C RANGE WL ALLOW FOR CONTINUED WDSPRD LES...ESPECIALLY
AFTER MID EVNG WHEN IMPACTS OF DAYTIME HEATING WOULD TEND TO
SUBSIDE. WITH INVRN BASE OVER THE W FALLING TO ARND 4K FT OVER THE
W...SHSN INTENSITY IN THIS AREA WL BE WEAKER WITH SHORTER FETCH/LESS
MODERATION OF UPSTREAM AIRMASS. BUT STILL WENT WITH LIKELY POPS
GIVEN FVRBL NW FLOW/OVERWATER INSTABILITY/NOCTURNAL COOLING THAT WL
ALLOW LES BANDS TO REDEVELOP.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 440 AM EDT MON APR 1 2013
DESPITE ADEQUATE DELTA TS PERSISTING INTO TUESDAY FOR LAKE
EFFECT...SFC-H85 FLOW WILL BECOME INCREASINGLY ANTICYCLONIC THROUGH
THE DAY. IN ADDITION...INVERSION HEIGHTS BEGIN TO FALL OFF
SIGNIFICANTLY BELOW 5KFT. THUS...EXPECT OVERALL COVERAGE AND
INTENSITY OF LAKE EFFECT TO BE ON THE WANE AS THE DAY PROGRESSES.
TEMPERATURES WILL REMAIN WELL BELOW NORMAL WITH A SIGNIFICANT AMOUNT
OF CLOUDINESS DOWNWIND OF LAKE SUPERIOR.
LAKE CLOUDS AND EVEN A FEW FLURRIES WILL PERSIST INTO THE MORNING
WEDNESDAY OVER THE EAST. AS SURFACE RIDGE AXIS MOVES OVERHEAD
THROUGH THE DAY EXPECT SKIES TO BECOME MOSTLY SUNNY AREA WIDE.
TEMPERATURES SHOULD REBOUND BACK ABOVE FREEZING AND EVEN APPROACH 40
ACROSS THE WEST WITH WARM ADVECTION INCREASING DURING THE AFTERNOON
AND MORE SUNSHINE.
MODELS COMING INTO BETTER AGREEMENT WITH THE TIMING OF THE NEXT
SHORTWAVE AND SFC TROUGH EXPECTED TO MOVE ACROSS THE AREA WED
NIGHT/THU. THE TREND HAS BEEN TOWARD QUICKER MOVEMENT WITH THE TROUGH.
SYSTEM IS FAIRLY MOISTURE STARVED...SO DESPITE PRECIP TYPE BEING A
CHALLENGE BETWEEN RAIN AND SNOW...AMOUNTS WILL BE LIGHT ENOUGH TO BE
PRETTY INSIGNIFICANT. COLD ADVECTION BEHIND THE TROUGH SHOULD PUSH
85H TEMPS BACK DOWN TO THE -10 TO -14C RANGE BY FRIDAY. PROBABLY NOT
QUITE COLD ENOUGH FOR LAKE EFFECT THIS TIME AROUND...BUT COLDER AIR
WILL KEEP DAYTIME TEMPS BELOW AVERAGE ONLY IN THE 30S.
FORECAST FOR NEXT WEEKEND STILL PRETTY CHALLENGING...BUT MODELS
SHOWING SOME SIGNS THAT THEY ARE TRYING TO CONVERGE ON A MORE
PROBABLE OUTCOME. SHORTWAVE ENERGY AND ASSOCIATED SURFACE LOW MOVING
OUT OF THE PLAINS LOOKING LIKE THEY MAY NOW TRACK THROUGH THE LOWER
LAKES WHICH WOULD STILL RESULT IN SOME LIGHT SNOWFALL ACROSS
SOUTHERN AREAS SATURDAY INTO SUNDAY BUT SPARE THE AREA FROM A MORE
SIGNIFICANT STORM. IT IS STILL SOMETHING TO KEEP AN EYE ON AS WE
HEAD THROUGH THE WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 125 PM EDT MON APR 1 2013
DRY AIR MOVING ACROSS LAKE SUPERIOR SHOULD HELP TO KEEP CMX AND IWD
AT OR ABOVE MVFR THROUGH THE TAF PERIOD. CEILINGS SHOULD REMAIN AT
OR ABOVE 3KFT FOR EACH TAF SITE...WITH KSAW POSSIBLY REACHING VFR
CEILINGS THIS AFTERNOON AND EVENING AS WNW WINDS ALLOW FOR
DOWNSLOPING OVER THAT AREA. VISIBILITIES ARE A BIT TRICKY AS
INTERMITTENT SNOW SHOWERS PASS OVER EACH TAF SITE...OCCASIONALLY
REDUCING VISIBILITY TO MVFR OR LOWER AT TIMES...ESPECIALLY OVER THE
KEWEENAW WHERE WINDS MAY REMAIN GUSTY THROUGH THE TAF PERIOD
INCREASING THE POTENTIAL FOR BLOWING SNOW. WINDS ARE EXPECTED TO
DECREASE OVER THE REMAINING TAF SITES AS PRESSURE GRADIENT IS
REDUCED AS THE SURFACE LOW SHIFTS TO CENTRAL QUEBEC BY TUESDAY
MORNING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 440 AM EDT MON APR 1 2013
AS LO PRES OVER SE CANADA CONTINUES TO THE E AND THE PRES GRADIENT
WEAKENS...EXPECT NW WINDS TO SLOWLY DIMINISH AND BELOW GALE FORCE
OVER THE CENTRAL BY MID MORNING...SO HASTENED THE ENDING OF THE GALE
WARNINGS FOR THIS AREA. ALTHOUG NW GALES TO 35 KTS WILL CONTINUE
LONGER OVER THE E INTO THIS EVENING...ENDED THE GALES FOR THAT AREA
EARLIER AS WELL. WINDS/WAVES WILL BE SUFFICIENT TO MAINTAIN FREEZING
SPRAY OVER AT LEAST THE E HALF THRU TONIGHT.
WINDS WILL REMAIN PRETTY GUSTY UP TO 30 KNOTS OVER THE EASTERN LAKE
THROUGH THE DAY ON TUESDAY...BUT AS SURFACE RIDGE AXIS PUSHES IN
FROM THE WEST PRESSURE GRADIENT WILL RELAX AND WINDS WILL DIMINISH
DURING THE EVENING. UNTIL THAT TIME...FREEZING SPRAY SHOULD CONTINUE
ACROSS THE EASTERN LAKE. AFTER A BRIEF RESPITE ON
WEDNESDAY...SOUTHWESTERLY WINDS UP TO 25 KNOTS AHEAD OF THE NEXT
TROUGH CROSSING THE LAKE WILL INCREASE WEDNESDAY NIGHT INTO EARLY
THURSDAY BEFORE SHIFTING TO THE NORTHWEST DURING THE DAY THURSDAY
INTO THURSDAY NIGHT. WINDS FOR FRIDAY INTO NEXT WEEKEND SHOULD BE
BELOW 20 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR
MIZ006-085.
WINTER WEATHER ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR MIZ007.
LAKE SUPERIOR...
GALE WARNING UNTIL 2 AM EDT TUESDAY FOR LSZ250-251-266-267.
GALE WARNING UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ249.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...MZ
AVIATION...KEC
MARINE...KC/MZ
AREA FORECAST DISCUSSION
NWS BISMARCK ND
547 PM CDT MON APR 1 2013
.UPDATE...
ISSUED AT 546 PM CDT MON APR 1 2013
LATEST SUITE OF SATELLITE IMAGERY/SURFACE OBSERVATIONS SHOWS
CLEAR SKIES ACROSS WESTERN AND CENTRAL NORTH DAKOTA WITH THE
EXCEPTION OF A SCT/BKN CUMULUS DECK OVER THE HIGHER TERRAIN IN THE
SOUTHWEST...IN CONJUNCTION WITH A LOW LEVEL BAROCLINIC ZONE.
TEMPERATURES WERE IN THE 50S ACROSS SOUTHEAST MONTANA...WITH
TEMPERATURES AROUND 40 IN OUR SOUTHWEST ZONES. OTHERWISE...A
1030MB SURFACE HIGH PRESSURE SITS OVER NORTHERN NORTH DAKOTA THIS
EVENING PRODUCING CLEAR SKIES AND LIGHT WINDS.
FURTHER UPSTREAM...WATER VAPOR IMAGERY SHOWS A WEAK SHORTWAVE
TROUGH ALOFT OVER NORTHEAST SASKATCHEWAN ALONG WITH A SURFACE
REFLECTION/SURFACE TROUGH PER MSAS...ALL MOVING SOUTHEAST WITH
TIME. THIS SHORTWAVE IS FORECAST TO MOVE TO LAKE WINNIPEG BY 06Z
TUESDAY...THEN INTO NORTHERN MINNESOTA BY 12Z TUESDAY. BEST UPWARD
VERTICAL MOTION/H85-H3 OMEGA FIELD IS FORECAST OVER SOUTHERN
MANITOBA DURING THE 06Z-12Z TUESDAY TIME FRAME. HOWEVER THE 18Z
NAM/GFS AND LATEST RAP MODEL PRODUCE A SWATH OF 80 TO 90 PERCENT
H85-H7 RH LATER TONIGHT ASSOCIATED WITH THIS SHORTWAVE. THE
NAM/GFS ALSO PAINT LIGHT QPF OF 0.01 COVERING PORTIONS OF BOTTINEAU
AND ROLETTE COUNTIES BETWEEN 09Z AND 12Z TUESDAY. THE LATEST RAP
MODEL KEEPS THE PRECIPITATION JUST EAST OF BOTTINEAU/ROLETTE
COUNTIES. OBSERVATIONS AND PAST WEATHER IN LOCATION OF CURRENT
SHORTWAVE DOES REVEAL A POCKET OF LOW/MID LEVEL CLOUDS AND A BRIEF
PERIOD OF ISOLATED FLURRIES.
FOR THIS UPDATE...HAVE COLLABORATED WITH NEIGHBORING OFFICES TO
INCREASE THE SKY GRIDS FOR THE NORTHEAST TONIGHT...BUT HOLD OFF
ON ANY MENTION OF PRECIPITATION AS BEST VERTICAL MOTION IS
FORECAST NORTH/EAST. WILL AWAIT THE 00Z MODEL RUNS AND KEEP A
CLOSE EYE ON THE RAP MODEL THIS EVENING FOR ANY CHANGES. UNTIL
OBSERVATIONS SUGGEST SOMETHING DEVELOPING CLOSER TO OUR NORTHERN
BORDER...WILL STAY THE COURSE WITH THE DRY FORECAST. REST OF
FORECAST IS IN GOOD SHAPE.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 346 PM CDT MON APR 1 2013
HIGH PRESSURE WILL GRADUALLY SHIFT EAST OF THE REGION THROUGH THE
PERIOD. DRY CONDITIONS WILL PREVAIL AS A RESULT. BELOW NORMAL
TEMPERATURES WILL CONTINUE THIS AFTERNOON AND TONIGHT.
HOWEVER...RETURN FLOW DEVELOPING ACROSS THE REGION COMBINED WITH NO
SNOW PACK SOUTHWEST OF THE MISSOURI WILL ALLOW TUESDAY AFTERNOON
HIGHS TO BE ABOVE NORMAL SOUTHWEST. BELOW NORMAL TEMPERATURES WILL
CONTINUE NORTH AND EAST OF THE MISSOURI RIVER...WHERE THE SNOW PACK
IS LOCATED.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 346 PM CDT MON APR 1 2013
THE MAIN FORECAST CHALLENGES FOR THE EXTENDED PERIOD INCLUDE
PRECIPITATION CHANCES AND PRECIPITATION TYPE. 12Z SUITE OF MODEL
SOLUTIONS ARE IN AGREEMENT EARLY IN THE PERIOD...WITH SOLUTIONS
DIVERGING LATE THIS WEEK.
WARM AIR ADVECTION WILL CONTINUE ACROSS THE AREA TUESDAY NIGHT AND
WEDNESDAY AHEAD OF A UPPER LEVEL WAVE/SURFACE LOW PRESSURE SYSTEM
THAT IS FORECAST TO PASS OVER NORTH DAKOTA. WARM H850
TEMPERATURES OF +6 TO +10C WILL BE FIRMLY IN PLACE WEDNESDAY AS
PRECIPITATION BEGINS ACROSS THE NORTHWEST AND SPREADS SOUTHEAST
ACROSS THE AREA WEDNESDAY. PRECIPITATION WILL BEGIN AS LIGHT
FREEZING RAIN AND TRANSITION TO LIGHT RAIN DURING WEDNESDAY
AFTERNOON. ACROSS THE SOUTHWEST...ISOLATED WEAK THUNDERSTORMS ARE
POSSIBLE...WHERE TEMPERATURES WILL BE IN THE 60S WITH SURFACE BASED
CAPE IN THE 100 TO 200 J/KG ADVERTISED BY THE 12Z NAM. BEFORE
ENDING WEDNESDAY EVENING...A TRANSITION FROM LIGHT RAIN TO A
WINTRY MIX OF SNOW...FREEZING RAIN...AND POSSIBLY SLEET WILL BE
SEEN AS A COLD FRONT MOVES SOUTH FROM CANADA.
COOLER TEMPERATURES WILL BE SEEN WEDNESDAY NIGHT AND THURSDAY...AS
COLD AIR COMMENCES FOLLOWING THE PASSAGE OF THE AFOREMENTIONED
COLD FRONT. HOWEVER...ACROSS THE SNOW LESS AREAS...TEMPERATURES
WILL BE WARMEST WITH TEMPERATURES IN 50S ON THURSDAY. FOR
LOCATIONS ACROSS THE SNOWPACK...TEMPERATURES WILL BE IN THE LOW TO
MID 30S.
STARTING FRIDAY...AN ACTIVE PERIOD OF WEATHER IS EXPECTED
TO START AS A SERIES OF UPPER LEVEL WAVES AND THEIR SURFACE
REFLECTIONS ARE PROGGED TO MOVE ACROSS THE AREA IN NORTHWESTERLY
FLOW. UNCERTAINTY REMAINS IN THE PLACEMENT AND TYPE OF
PRECIPITATION ACROSS NORTH DAKOTA...AS THERE IS DISAGREEMENT
AMONGST THE 12Z MODEL SOLUTIONS. THE 12Z GEM/GFS ARE MORE
AGGRESSIVE WITH QPF ACROSS THE WEST AND CENTRAL VERSUS THE 12Z EC
SOLUTION. THE 12Z EC KEEPS THE BULK OF THE PRECIPITATION FURTHER
NORTH ACROSS SOUTHERN MANITOBA AND SASKATCHEWAN.
AT THIS TIME HAVE UTILIZED A BLEND OF MODEL SOLUTIONS DURING THE
FRIDAY TO MONDAY PERIOD...WHICH GIVE A WIDE ARRAY OF PRECIPITATION
TYPES. AT THIS MOMENT...IT LOOKS LIKE THE SOUTHWEST WILL REMAIN
MOSTLY RAIN AS IT REMAINS IN THE WARM H850 TEMPERATURES OF +4 TO
+8 C. ELSEWHERE...A LIGHT WINTRY MIX OF SNOW...FREEZING RAIN...AND
POSSIBLY SLEET MAY OCCUR. BY SUNDAY EVENING AND
MONDAY...PRECIPITATION TYPE WILL BE SNOW...AS ANOTHER COLD FRONT
DROPS SOUTH OUT OF CANADA. FOLLOWING THE PASSAGE OF THE COLD
FRONT...COLDER H850 TEMPERATURES OF -8 TO -12 C ARE POSSIBLE AT
THE BEGINNING OF NEXT WEEK...AS A SURFACE HIGH PRESSURE STARTS TO
MOVE SOUTH.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING...
ISSUED AT 546 PM CDT MON APR 1 2013
GENERALLY CLEAR SKIES/VFR CONDITIONS WILL PREVAIL OVER WESTERN AND
CENTRAL NORTH DAKOTA THROUGH THE 00Z TAF PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...TM
LONG TERM...LTH
AVIATION...KS
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1113 AM MDT MON APR 1 2013
.UPDATE...
ISSUED AT 1047 AM MDT MON APR 1 2013
CURRENT SURFACE ANALYSIS SHOWS CANADIAN HIGH PRESSURE OVER EASTERN
PORTIONS OF THE DAKOTAS. UPPER LEVEL ANALYSIS SHOWS LARGE TROF
CENTERED OVER THE GREAT LAKES REGION...WITH RIDGING OVER THE
PACIFIC NW. A CUTOFF LOW IS SLOWLY MOVING EAST-SOUTHEAST ACROSS
NV. SKIES CURRENTLY RANGE FROM SUNNY ACROSS NORTHEAST WY AND
SOUTHWESTERN SD TO PARTLY TO MOSTLY CLOUDY FROM NORTHWESTERN INTO
CENTRAL SD. BAND OF CLOUDS IS SLOWLY DISSIPATING ACROSS THESE
AREAS...WITH MOSTLY SUNNY SKIES EXPECTED BY EARLY AFTERNOON.
NEAR TO SLIGHTLY BELOW AVERAGE TEMPERATURES CAN BE EXPECTED THIS
AFTERNOON...WITH HIGHS IN THE MID 40S TO MID 50S...WARMEST OVER
NORTHEASTERN WY AND COOLEST OVER FAR EASTERN AREAS. WINDS WILL
REMAIN RELATIVELY LIGHT AND VARIABLE THROUGH THE AFTERNOON. MAIN
ADJUSTMENTS TO THE FORECAST WERE TO TWEAK CLOUD COVER AND WINDS
FOR THE REST OF TODAY.
&&
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 240 AM MDT MON APR 1 2013
ACTIVE PROGRESSIVE NORTHERN STREAM FLOW WILL DOMINATE
THE WEATHER IN THE PERIOD...WITH A LARGE SCALE SPLIT FLOW REGIME.
THIS WILL OFFER WARM DOWNSLOPE PAC ORIGIN FLOW INTO THE AREA...ESP
TUE. GREAT LAKES UPPER TROUGH WILL SLOWLY SHIFT EAST WITH DEEP LAYER
RIDGING DEVELOPING TODAY...INITIATING WAA BY THIS AFTERNOON OVER THE
WESTERN FA. THE ONLY FORECAST CONCERN TODAY WILL BE THE EVOLUTION OF
THE CURRENT STRATUS IN PLACE ACROSS THE EASTERN FA...WHICH MAY
HAMPER T RISES. THE ONLY FORECAST MODELS WHICH SEEMS TO HAVE ANY
SORT OF HANDLE ON THE EXISTENCE OF CLOUD COVER IS THE RAP AND LOCAL
WRF...WITH ALL OTHER GUIDANCE REMAINING TOO DRY IN THE LL/S.
RAP/LOCAL WRF BOTH INDICATE THAT INCREASING DRY WESTERLY FLOW AT THE
BL TOP SHOULD HELP ERODE CLOUD COVER WEST TO EAST THROUGH MORNING
AND TRIED TO INCORPORATE THIS IDEA INTO THE GRIDS. ONCE CLOUDS
CLEAR...SKIES WILL REMAIN MOSTLY CLEAR THROUGH THE PERIOD...SAVE FOR
SOME PASSING CIRRUS.
TEMPS WILL REMAIN ON THE COOL SIDE ACROSS MOST OF THE AREA
TODAY...WITH THE SD PLAINS BEING THE COOLEST. NE WY WILL SEE QUICK
RESPONSE TO ENSUING WAA WITH MANY PLACES EXPECTED TO BE IN THE 50S
THERE. HAVE ADJUSTED TEMPS UP SOME...GIVEN LATEST BLENDED GUIDANCE
WITH STRONG INSOLATION EXPECTED. MUCH WARMER CONDITIONS EXPECTED
TUE...WITH 50S AND 60S COMMON MOST PLACES. HAVE WARMED MOST PLACES
A FEW DEGREES TUE...ESP NE WY. STRONG INSOLATION SHOULD SUPPORT
SUPERADIABATS AT MOST LOCATIONS GIVEN WEAK LL FLOW...WITH TEMPS
WARMER THAN CURRENT FORECAST HIGHS CERTAINLY POSSIBLE. THE NEXT
NORTHERN STREAM IMPULSE WILL APPROACH THE REGION TUE...WITH WAA
RAMPING UP...AS WELL AS LL SOUTHERLY FLOW TUE NIGHT. THIS SHOULD
KEEP TEMPS UP AT MANY PLACES OVERNIGHT TUE...GIVEN TURBULENT
MIXING...ESP IN THE LEE DOWNSLOPE AREAS OF THE BH.
.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 240 AM MDT MON APR 1 2013
UPPER LEVEL RIDGE FLATTENS LATE WEDNESDAY AS A COLD FRONT CROSSES
THE AREA...BRINGING A CHANCE FOR RAIN SHOWERS AND AN ISOLATED
THUNDERSTORM. RAIN SHOWERS WILL LINGER INTO THURSDAY...MAINLY ACROSS
NORTHERN PORTIONS OF THE AREA. A MORE UNSETTLED PATTERN WILL DEVELOP
BY THE WEEKEND AS A LARGE UPPER TROF DEVELOPS OVER THE WEST COAST
AND A SERIES OF DISTURBANCES MOVE ACROSS THE NORTHERN PLAINS IN WEST
TO SOUTHWEST FLOW. TEMPERATURES WILL GENERALLY STAY ABOVE AVERAGE
LATE IN THE WEEK AND LIKELY DROP CLOSER TO AVERAGE LEVELS DURING THE
WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1109 AM MDT MON APR 1 2013
LEFTOVER MARGINALLY MVFR CIGS FROM KPHP TO KVTN WILL MOVE SLOWLY
EAST AND DISSIPATE EARLY THIS AFTERNOON AS BOUNDARY LAYER MIXES
OUT. SOME VFR CU IS EXPECTED FROM K2WX TO KVTN FOR THE AFTERNOON.
OTHERWISE...VFR CONDITIONS WILL BE THE RULE THROUGH THE PERIOD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...26
SHORT TERM...JC
LONG TERM...15
AVIATION...HELGESON
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1047 AM MDT MON APR 1 2013
.UPDATE...
ISSUED AT 1047 AM MDT MON APR 1 2013
CURRENT SURFACE ANALYSIS SHOWS CANADIAN HIGH PRESSURE OVER EASTERN
PORTIONS OF THE DAKOTAS. UPPER LEVEL ANALYSIS SHOWS LARGE TROF
CENTERED OVER THE GREAT LAKES REGION...WITH RIDGING OVER THE
PACIFIC NW. A CUTOFF LOW IS SLOWLY MOVING EAST-SOUTHEAST ACROSS
NV. SKIES CURRENTLY RANGE FROM SUNNY ACROSS NORTHEAST WY AND
SOUTHWESTERN SD TO PARTLY TO MOSTLY CLOUDY FROM NORTHWESTERN INTO
CENTRAL SD. BAND OF CLOUDS IS SLOWLY DISSIPATING ACROSS THESE
AREAS...WITH MOSTLY SUNNY SKIES EXPECTED BY EARLY AFTERNOON.
NEAR TO SLIGHTLY BELOW AVERAGE TEMPERATURES CAN BE EXPECTED THIS
AFTERNOON...WITH HIGHS IN THE MID 40S TO MID 50S...WARMEST OVER
NORTHEASTERN WY AND COOLEST OVER FAR EASTERN AREAS. WINDS WILL
REMAIN RELATIVELY LIGHT AND VARIABLE THROUGH THE AFTERNOON. MAIN
ADJUSTMENTS TO THE FORECAST WERE TO TWEAK CLOUD COVER AND WINDS
FOR THE REST OF TODAY.
&&
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 240 AM MDT MON APR 1 2013
ACTIVE PROGRESSIVE NORTHERN STREAM FLOW WILL DOMINATE
THE WEATHER IN THE PERIOD...WITH A LARGE SCALE SPLIT FLOW REGIME.
THIS WILL OFFER WARM DOWNSLOPE PAC ORIGIN FLOW INTO THE AREA...ESP
TUE. GREAT LAKES UPPER TROUGH WILL SLOWLY SHIFT EAST WITH DEEP LAYER
RIDGING DEVELOPING TODAY...INITIATING WAA BY THIS AFTERNOON OVER THE
WESTERN FA. THE ONLY FORECAST CONCERN TODAY WILL BE THE EVOLUTION OF
THE CURRENT STRATUS IN PLACE ACROSS THE EASTERN FA...WHICH MAY
HAMPER T RISES. THE ONLY FORECAST MODELS WHICH SEEMS TO HAVE ANY
SORT OF HANDLE ON THE EXISTENCE OF CLOUD COVER IS THE RAP AND LOCAL
WRF...WITH ALL OTHER GUIDANCE REMAINING TOO DRY IN THE LL/S.
RAP/LOCAL WRF BOTH INDICATE THAT INCREASING DRY WESTERLY FLOW AT THE
BL TOP SHOULD HELP ERODE CLOUD COVER WEST TO EAST THROUGH MORNING
AND TRIED TO INCORPORATE THIS IDEA INTO THE GRIDS. ONCE CLOUDS
CLEAR...SKIES WILL REMAIN MOSTLY CLEAR THROUGH THE PERIOD...SAVE FOR
SOME PASSING CIRRUS.
TEMPS WILL REMAIN ON THE COOL SIDE ACROSS MOST OF THE AREA
TODAY...WITH THE SD PLAINS BEING THE COOLEST. NE WY WILL SEE QUICK
RESPONSE TO ENSUING WAA WITH MANY PLACES EXPECTED TO BE IN THE 50S
THERE. HAVE ADJUSTED TEMPS UP SOME...GIVEN LATEST BLENDED GUIDANCE
WITH STRONG INSOLATION EXPECTED. MUCH WARMER CONDITIONS EXPECTED
TUE...WITH 50S AND 60S COMMON MOST PLACES. HAVE WARMED MOST PLACES
A FEW DEGREES TUE...ESP NE WY. STRONG INSOLATION SHOULD SUPPORT
SUPERADIABATS AT MOST LOCATIONS GIVEN WEAK LL FLOW...WITH TEMPS
WARMER THAN CURRENT FORECAST HIGHS CERTAINLY POSSIBLE. THE NEXT
NORTHERN STREAM IMPULSE WILL APPROACH THE REGION TUE...WITH WAA
RAMPING UP...AS WELL AS LL SOUTHERLY FLOW TUE NIGHT. THIS SHOULD
KEEP TEMPS UP AT MANY PLACES OVERNIGHT TUE...GIVEN TURBULENT
MIXING...ESP IN THE LEE DOWNSLOPE AREAS OF THE BH.
.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 240 AM MDT MON APR 1 2013
UPPER LEVEL RIDGE FLATTENS LATE WEDNESDAY AS A COLD FRONT CROSSES
THE AREA...BRINGING A CHANCE FOR RAIN SHOWERS AND AN ISOLATED
THUNDERSTORM. RAIN SHOWERS WILL LINGER INTO THURSDAY...MAINLY ACROSS
NORTHERN PORTIONS OF THE AREA. A MORE UNSETTLED PATTERN WILL DEVELOP
BY THE WEEKEND AS A LARGE UPPER TROF DEVELOPS OVER THE WEST COAST
AND A SERIES OF DISTURBANCES MOVE ACROSS THE NORTHERN PLAINS IN WEST
TO SOUTHWEST FLOW. TEMPERATURES WILL GENERALLY STAY ABOVE AVERAGE
LATE IN THE WEEK AND LIKELY DROP CLOSER TO AVERAGE LEVELS DURING THE
WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 540 AM MDT MON APR 1 2013
MVFR CIGS WILL PERSIST ACROSS THE WESTERN SOUTH DAKOTA PLAINS
THROUGH THE MORNING HOURS BEFORE LIFTING AND SHIFTING EAST BY 18Z.
VFR CONDITIONS ARE THEN EXPECTED THROUGH TUESDAY MORNING.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...26
SHORT TERM...JC
LONG TERM...15
AVIATION...15
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
329 PM CDT MON APR 1 2013
.SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...ANOTHER ONE OF THESE
FORECASTS WHERE MESO-SCALE INFLUENCES MAY PLAY HAVOC ON WHAT
TRANSPIRES TONIGHT. MAIN FLY IN OINTMENT NOW IS THAT LOTS OF
STRATUS IS JUST ACROSS THE RIVER AND TEMPERATURES OUT WEST ARE NOT
THAT WARM...SO SEA BREEZE LIMITED OUT THERE AS WELL AS DAYTIME
HEATING. THUS...CONVERGING BOUNDARIES LIKE LAST NIGHT NOT PRESENT
AND STORMS MAY HAVE A HARD TIME FIRING UP DIRECTLY WEST OF
FORECAST AREA. HOWEVER...STORMS ARE DEVELOPING FARTHER NORTHWEST
OF STRATUS DECK (HAVE A LONG WAY TO GO THOUGH). STILL AM GOING
TO GO WITH LOW CHANCE POPS NEAR RIO GRANDE AND DIMINISH THEM
FARTHER EAST. THING THAT HELPS CONVECTION TO DEVELOP IS EASTERLY
UPSLOPE FLOW SO DO NOT WANT TO GO TOO LOW ON POPS (ESPECIALLY WITH
SLIGHT RISK IN AREA)...AND WITH SPC 4 KM MODEL AND HRRR MODEL
SHOWING ACTIVITY MOVING IN THERE. OTHERWISE...TEMPERATURES SHOULD
BE SIMILAR TO LAST NIGHT...EXCEPT WHERE CONVECTION COULD COOL
AIR SOME. NO SIGNIFICANT FOG EXPECTED.
UPPER LEVEL JET IMPACTS AREA ON TUESDAY AS CAP BREAKS/WEAKENS. AM
GOING HIGH CHANCE POPS EASTERN AREAS...TAD LOWER OUT WEST. MORE
CLOUDS AND RAIN-COOLED AIR MEANS LOWER TEMPERATURES TUESDAY. SOME
JET DYNAMICS REMAIN TUESDAY NIGHT AS FRONT APPROACHES...SO PRETTY
MUCH HAVE KEPT POPS SIMILAR TO PREVIOUS FORECAST WITH SLIGHT
ADJUSTMENT OF HIGHER POPS A BIT MORE TOWARD THE NORTHEAST (AREA
ADJUSTEMENT...STILL NO MORE THAN 70 POPS). WITH COOLER AIR
REMAINING NORTH OF AREA (BUT PROBABLY SOME CONVECTION AROUND
COOLING THINGS OFF)...WILL GO A BIT COOLER TUESDAY NIGHT THAN
TONIGHT. SPECIAL WEATHER STATEMENT HAS BEEN ISSUED TO HIGHLIGHT
UPCOMING EVENT.
&&
.MARINE (TONIGHT THROUGH TUESDAY NIGHT)...SEA FOG ALBEIT LIGHT
REMAINS IN THE FORECAST AS VISIBLE SATELLITE AND OBSERVATIONS SHOW
SOME OUT THERE. OVERALL VISIBILITIES SHOULD REMAIN ABOVE 2 NM.
GENERALLY WEAK TO MODERATE ESE/SE FLOW THROUGH THE PERIOD. RAIN
CHANCES INCREASE MAINLY LATE TUESDAY AND TUESDAY NIGHT.
&&
.LONG TERM (WEDNESDAY THROUGH SUNDAY)...OVERALL TREND CONTINUES
ABUNDANT GULF MOISTURE ACROSS THE REGION WITH PWATS 1.3 TO 1.5
INCHES...WHICH IS JUST OVER 75 PERCENT OF NORMAL PWATS FOR THIS TIME
OF YEAR. TIMING OF THE FRONT STILL REMAINS A CHALLENGE ALTHOUGH
MODEST AGREEMENT BETWEEN THE EURO/CANADIAN/NAM AROUND 00Z...WITH THE
GFS LAGGING A FEW HOURS BEHIND. A PREFRONTAL WIND SHIFT SHOULD TAKE
PLACE BETWEEN 18Z-00Z. WITH MULTIPLE SHORTWAVES ROUNDING THE
SOUTHERN PERIPHERY OF THE MIDLEVEL LOW //POSITIONED OVER THE CENTRAL
PLAINS//...CONTINUED HIGH END CHANCE TO LIKELY POPS GOING INTO
WEDNESDAY...WITH MOST ACTIVITY IN THE MORNING BEING MORE OF A SHOWER
ACTIVITY UNDER A WEAK CAP. HOWEVER...DID CONTINUE THUNDER WORDING AS
A VORT MAX AND 60 KNOT JET MOVE OVER THE AREA. DID SHOW THE INCREASE
IN CHANCES INTO THE AFTERNOON AS FURTHER COOLING IN THE MIDLEVELS
TAKES PLACE WITH THE FRONT SLOWLY MOVING SOUTHWARD. CONCERN DOES
EXIST IN THE AFTERNOON TO EARLY EVENING FOR STRONG TO SEVERE AS
LAPSE RATES STEEPEN WITH LI VALUES OF -7C TO -9C. HOWEVER...THE
ONSHORE IS WEAK TO FEED INTO ANY STORMS. CURRENTLY IF ANYTHING
DEVELOPS INTO THE STRONG TO SEVERE CATEGORY...SHOULD BE MORE OF
PULSE STORMS...WITH BETTER CHANCES ALONG THE FRONT ITSELF. WILL
CONTINUE TO MONITOR THE DEVELOPMENT OF THIS WEATHER EVENT. MOISTURE
AND THE MIDLEVEL LOW PULLS TO THE NORTHEAST WITH DRYING FROM WEST TO
EAST LATE WEDNESDAY INTO THURSDAY WITH HIGH PRESSURE ENTERING THE
REGION. QUIET WEATHER TO PERSIST INTO THE WEEKEND WITH A ONSHORE
FLOW DEVELOPING SATURDAY. TEMPERATURES TO COOL INTO THE 70S AREAWIDE
THURSDAY...WITH A WARMING TREND INTO THE WEEKEND UNDER MOSTLY CLEAR
TO PARTLY CLOUDY SKIES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 68 82 69 81 55 / 10 50 50 70 40
VICTORIA 66 80 66 76 52 / 10 50 70 70 40
LAREDO 67 86 70 83 58 / 40 30 30 40 10
ALICE 68 86 69 83 55 / 10 50 50 60 30
ROCKPORT 68 77 68 75 55 / 10 50 60 70 40
COTULLA 65 83 67 78 53 / 30 30 50 50 10
KINGSVILLE 67 84 69 82 55 / 10 50 40 60 40
NAVY CORPUS 68 78 69 76 58 / 10 50 50 70 40
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...SHORT TERM
CB/85...LONG TERM
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
208 PM CDT MON APR 1 2013
.SHORT TERM /NOW THROUGH TUESDAY NIGHT/...THE AREA REMAINS IN
QUASI-ZONAL FLOW ALOFT WITH AN UPPER LEVEL TROUGH LOCATED OVER THE
GREAT BASIN AND A WEAK IMPULSE RIDING WESTERLY FLOW IN NORTHERN
MEXICO SOUTH OF THE TEXAS BIG BEND. AT THE SURFACE...SOUTHEASTERLY
FLOW CONTINUES TO ADVECT MOISTURE FROM THE GULF OF MEXICO WITH A
COLD FRONT LOCATED ACROSS OKLAHOMA AND THE TEXAS PANHANDLE. A
1020MB HIGH IS LOCATED ACROSS THE ARKLAMISS.
FOR THE REST OF THE AFTERNOON AND INTO THIS EVENING...WILL CONTINUE
TO SEE CLOUDS BREAK UP AS MIXING AND DAYTIME HEATING CONTINUES.
THICKER STRATOCU RESIDES OVER ZAPATA/JIM HOGG/STARR COUNTIES AND MAY
BE A LITTLE HARDER TO BREAK UP CLOUDS IN THIS AREA. EVEN THOUGH
THICK CLOUDS ARE LOCATED HERE...TEMPERATURES HAVE WARMED NICELY AND
ARE ACTUALLY ABOVE FORECASTED HOURLY TEMPERATURES BUT LOOK GOOD FOR
THE HIGHS THIS AFTERNOON. WEAK IMPULSE TO OUR WEST IS FORECAST TO
SPARK CONVECTION ON THE SIERRA MADRE LATER THIS AFTERNOON AS IT
MOVES EAST. LATEST HRRR AND SPC 4KM WRF CONTINUE TO ROLL CONVECTION
OFF THE HIGHER TERRAIN AND MAKE A RUN AT OUR WESTERN ZONES. CURRENT
20 POPS OUT WEST LOOK GOOD FOR THIS EVENING AND MADE ONLY MINOR
ADJUSTMENTS TO MOVE JUST A LITTLE EASTWARD. ANY STORMS THAT DO CREEP
INTO OUR AREA WILL QUICKLY DISSIPATE TOWARDS MID EVENING AS BOUNDARY
LEVEL STABILIZES.
FOR TONIGHT...LOW CLOUDS WILL MOVE BACK IN ON SOUTHEASTERLY LOW
LEVEL WINDS BY MID TO LATE EVENING. NAM12/RAP/HRRR SHOW SIGNALS OF
SEA FOG DEVELOPING AND/OR ADVECTING IN TO THE COASTAL AREAS
OVERNIGHT. ADDED AREAS OF FOG ALONG THE COASTLINE WITH PATCHY FOG
INLAND. WILL HOLD OFF ON ANY DENSE FOG ADVISORY AT THIS TIME AND LET
SWING SHIFT MAKE THE CALL. INCREASED LOW TEMPERATURES SLIGHTLY WITH
EXPECTED ABUNDANCE OF LOW CLOUDS AND LOOKING AT MAINLY UPPER 60S TO
LOWER 70S.
FOR TUESDAY...WE WILL START OUT WITH THOSE LOW CLOUDS AND WILL BREAK
OUT AND DISSIPATE BY LATE MORNING. MIXING WILL TAKE PLACE BY MID
MORNING WITH GUSTY WINDS BY LATE MORNING. ANOTHER IMPULSE IS PROGGED
TO MOVE ACROSS THE AREA EARLY TUESDAY AFTERNOON. THERE IS PLACEMENT
ISSUES BETWEEN THE NAM AND GFS WITH THE NAM FURTHER NORTH AND THE
GFS IS ACROSS THE NORTHERN PORTION OF THE AREA AND IS WEAKER THAN
THE PREVIOUS RUN. KEPT POPS AS IS AND JUST TWEAKED LOCATION BASED ON
12Z GFS. A STRONG TO SEVERE STORM IS POSSIBLE GIVEN THE
THERMODYNAMIC ENVIRONMENT.
FOR TUESDAY NIGHT...THAT IMPULSE IS WELL NORTH OF THE AREA WITH JUST
A FEW SHOWERS LEFT OVER IN THE COASTAL WATERS. ATMOSPHERE WILL
STABILIZE RATHER RAPIDLY AFTER SUNSET WITH SKIES BECOMING CLOUDY
ONCE AGAIN. COLD FRONT WILL SAG INTO NORTH CENTRAL TEXAS WITH A SFC
LOW SOUTH OF THE TEXAS BIG BEND. CLOUDS WILL KEEP LOWS
UP...COMPARABLE TO TONIGHT.
.LONG TERM /WEDNESDAY THROUGH MONDAY/...12Z MODEL RUN REMAINS
PERSISTENT ON THE TRACK AND STRENGTH OF THE MID TO UPPER LEVEL
TROUGH CURRENTLY OVER THE GREAT BASIN. BY 18Z WEDNESDAY GFS PLACES
THE UPPER TROUGH AXIS ACROSS NORTHWEST TEXAS AROUND 18Z WITH ITS
ASSOCIATED COLD FRONT APPROACHING THE NORTHERN PORTIONS OF THE
CWA. LARGE SCALE ASCENT COUPLED WITH LOW LEVEL CONVERGENCE ALONG
THE FRONT SHOULD BE THE COMBINATION NEEDED TO BRING ABOUT THE
CHANCE OF RAIN WE HAVE SEEN IN A WHILE. MODEST LOW LEVEL MOISTURE
WILL BE IN PLACE AND A LATE AFTERNOON FRONTAL PASSAGE SHOULD ALLOW
FOR SURFACE HEATING TO EXCEED GUIDANCE VALUES. SPC MAINTAINS
GENERAL THUNDERSTORM CHANCES FOR WEDNESDAY BUT CAN NOT RULE OUT
ISOLATED SEVERE STORMS AS THE ATMOSPHERE BECOMES INCREASINGLY
UNSTABLE. A DAY TO DAY ANALYSIS TO TAKE PLACE BEFORE WE ADD SEVERE
WORDING INTO THE FORECAST/GRIDS. POP GUIDANCE REMAINS AT LOW END
CHANCE BUT THIS MIGHT BE ON THE LOW END WITH DYNAMICS LOOKING A
BETTER THEN YESTERDAY AT THIS TIME. KEEP WED AND WEDNESDAY NIGHT
POPS CLOSE TO THE PREVIOUS FORECAST. AS MENTIONED TEMPERATURES
SHOULD CLIMB AHEAD OF THE COLD FRONT WITH A LATE AFTERNOON OR
EARLY EVENING PASSAGE. FORECAST HIGHS TO REMAIN ABOVE GUIDANCE
VALUES ESPECIALLY IF WE SEE MORE SUN PEAK THROUGH.
TROUGH AXIS AND SURFACE LOW PRESSURE QUICKLY EXITS TO THE EAST
THURSDAY MORNING. HUNG ON TO LOW POPS ACROSS THE COASTAL COUNTIES
BEFORE ENDING THURSDAY AFTERNOON AS THIS SYSTEM OPENS AND PUSHES
TO THE EAST. FAIR WEATHER ENSUES THURSDAY AFTERNOON INTO FRIDAY AS
SHORTWAVE RIDGING BUILDS OVERHEAD. COOL TO MILD TEMPERATURES
THURSDAY MORNING WITH SOME RECOVERY THURSDAY WITH HIGHS DROPPING
TO SLIGHTLY EARLY APRIL NORMALS.
GFS HAS BEEN INDICATING A QUICK RETURN OF GULF MOISTURE FRIDAY
NIGHT INTO SATURDAY. A WEAK DISTURBANCE IN THE ZONAL FLOW HAS BEEN
SEEN THE LAST FEW RUNS. ALTHOUGH GUIDANCE IS SHOWING VERY LOW POPS
ON SATURDAY WILL UP THE CHANCES SLIGHTLY TO MENTION ISOLATED
SHOWERS. MODEST DIVERGENCE AND SUFFICIENT MOISTURE...IF OCCURS
MIGHT BE ENOUGH FOR A FEW SHOWERS. WIND MACHINE TO POSSIBLY TURN
ON SUNDAY AND MONDAY AS NEXT TROUGH AND SURFACE LOW DEVELOP OUT
WEST. TEMPERATURES TO CLIMB AS USUAL.
&&
.MARINE /NOW THROUGH TUESDAY/GENERALLY FAVORABLE MARINE CONDITIONS
ARE EXPECTED THROUGH TUESDAY NIGHT WITH MODERATE EASTERLY TO
SOUTHEASTERLY WINDS. CONDITIONS MAY APPROACH EXERCISE CAUTION
LEVELS ON THE GULF OF MEXICO TONIGHT. SEAS SHOULD REMAIN LOW TO
MODERATE.
WEDNESDAY THROUGH SUNDAY...COLD FRONT ON TAP FOR A LATE WEDNESDAY OR
WEDNESDAY EVENING PASSAGE. LIGHT WINDS IN ADVANCE OF THE FRONT TO
SHIFT AND INCREASE FROM THE NORTH. SMALL CRAFT ADVISORIES STILL
EXPECTED WITH A 6 TO 12 HOUR WINDOW OF STRONG NORTH FLOW WEDNESDAY
NIGHT INTO EARLY THURSDAY AS SURFACE LOW PRESSURE DEVELOPS EAST OF
PADRE ISLAND ALONG THE FRONT. WITH THE SURFACE LOW TRACKING EAST
FAIRLY QUICKLY THURSDAY NORTH TO NORTHEAST WINDS TO WEAKEN. WINDS
VEER FRIDAY TO THE EAST AND SOUTHEAST BY FRIDAY NIGHT BUT THE
RETURN FLOW REMAINS LIGHT TO MODERATE. MORE SUBSTANTIAL INCREASE
OF SOUTHEAST WINDS RESUME SUNDAY INTO MONDAY AS THE GRADIENT
TIGHTENS WITH LOW PRESSURE DEEPENING ACROSS WESTERN TEXAS AND
NORTHEAST MEXICO.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 70 82 68 82 / 10 20 30 40
BROWNSVILLE 69 84 68 84 / 10 20 30 40
HARLINGEN 70 86 68 84 / 10 20 20 40
MCALLEN 70 87 70 86 / 10 30 20 40
RIO GRANDE CITY 70 90 70 87 / 20 30 20 30
SOUTH PADRE ISLAND 69 76 68 78 / 10 20 30 40
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
55...SHORT TERM
59...LONG TERM