Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/22/13
AREA FORECAST DISCUSSION
NWS PUEBLO CO
312 PM MDT SAT APR 20 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 312 PM MDT SAT APR 20 2013
SHORTWAVE PUSHING EASTWARD ACROSS COLORADO THIS AFTERNOON WAS
PRODUCING A GOOD DEAL OF VIRGA/LIGHT SHOWERS OVER THE
MOUNTAINS...THOUGH AMOUNT OF PRECIP REACHING THE GROUND IS LIKELY
MUCH LESS THAN RADAR SUGGESTS. HAVE EVEN SEE A COUPLE LIGHTNING
STRIKES OVER THE SRN SAN LUIS VALLEY NEAR THE NM BORDER...AS
LAPS/HRRR SUGGEST A LOCAL MAX OF INSTABILITY OVER THE VALLEY. NOT
SEEING MUCH SNOW YET ON CENTRAL MOUNTAIN WEB CAMS...THOUGH WILL KEEP
SNOW ADVISORY IN PLACE THE NEXT FEW HOURS TO ACCOUNT FOR SOME BRIEF
BURSTS OF SNOW UNDER HEAVIER CONVECTIVE SHOWERS. ELSEWHERE...WILL
KEEP SCATTERED POPS OVER THE MOUNTAINS INTO THE EVENING...WITH SOME
ISOLATED POPS FOR MAINLY VIRGA/SPRINKLES ALONG THE I-25 CORRIDOR.
COULD ALSO SEE SOME BRIEF GUSTY/ERRATIC WINDS OVER LOWER ELEVATIONS
AS PRECIP EVAPORATES WITHIN THE DRY SUB-CLOUD LAYER. DIDN`T INCLUDE
A MENTION OF THUNDER IN ANY AREAS...AS LATEST HRRR KEEP BEST
INSTABILITY NORTH OF THE PALMER DIVIDE. EXPECT MOST PRECIP TO END
QUICKLY WITH SUNSET AS INSTABILITY WANES AND UPPER WAVE MOVES
RAPIDLY INTO THE CENTRAL PLAINS. ON SUNDAY...WEAK SHORTWAVE MAY
SPARK SOME VIRGA/SPRINKLES OVER THE MTNS...BUT COVERAGE WILL BE MUCH
LESS THAN TODAY. MODELS TRY TO BREAK OUT SOME SPRINKLES OVER THE FAR
EASTERN PLAINS AS WELL...AS MODEST LOW LEVEL MOISTURE RETURNS
NORTHWARD. WILL IGNORE THIS FOR NOW...AS ANY PRECIP WILL BE VERY
LIGHT. WEST WINDS WILL PICK UP MOST AREAS AS UPPER JET MOVES ACROSS
AND FLOW IN THE 500/700 MB LAYER INCREASES TO 30-40 KNOTS...AND
LOCATIONS ACROSS THE HIGHER ELEVATIONS OF THE SANGRES/SAWATCH RANGES
WILL BECOME FAIRLY GUSTY BY AFTERNOON. MAX TEMPS LOOK WARMER MOST
AREA WITH BETTER MIXING AND A SUBTLE RISE IN 700 MB TEMPS...THOUGH
AT BEST...READINGS WILL STILL COME UP A COUPLE DEGF SHORT OF
SEASONAL MAXES.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 312 PM MDT SAT APR 20 2013
...ANOTHER STRONG COLD FRONT TO AFFECT THE AREA MONDAY AFTERNOON
THROUGH TUESDAY...
SUNDAY NIGHT-TUESDAY...LATEST MODELS IN DECENT AGREEMENT ON
DEVELOPING SYNOPTIC PATTERN THROUGH THE PERIOD...THOUGH CONTINUE TO
DIFFER ON AMOUNTS OF GENERATED PRECIPITATION. AT ANY RATE...WILL SEE
INCREASING WESTERLY FLOW ALOFT ACROSS THE REGION SUNDAY NIGHT AS AN
EMBEDDED SHORT WAVE EJECTS ACROSS THE NORTHERN ROCKIES AHEAD OF
PARENT TROUGH DIGGING INTO THE NORTHERN GREAT BASIN. COULD SEE A FEW
SHOWERS ACROSS MAINLY THE CENTRAL MTS THROUGH THE PIKES PEAK REGION
EARLY SUNDAY EVENING WITH FIRST PASSING WAVE WITH AN ASSOCIATED LEE
TROUGH TRANSLATING ACROSS THE EASTERN PLAINS KEEPING OVERNIGHT LOWS
ON THE MILD SIDE.
MODERATE TO STRONG WEST TO SOUTHWEST FLOW ALOFT PERSISTS ACROSS
THE AREA MONDAY AS PARENT SYSTEM CONTINUES TO TRANSLATE ACROSS THE
ROCKIES WITH FLOW ALOFT BECOMING MORE WEST TO NORTHWEST MONDAY NIGHT
AND TUESDAY AS UPPER TROUGH CONTINUES TO LIFT OUT ACROSS THE CENTRAL
HIGH PLAINS. MID LEVEL MOISTURE SLOWLY INCREASES FROM WEST TO EAST
ACROSS THE AREA MONDAY MORNING WITH A STRONG BACKDOOR COLD PUSHING
ACROSS EASTERN COLORADO LATE MONDAY MORNING AND AFTERNOON. MODELS A
TAD SLOWER WITH FRONT AND HAVE WARMED UP HIGHS SOME ACROSS EASTERN
COLORADO...WITH THE WARMEST READINGS EXPECTED SOUTH AND WEST OF THE
HIGHWAY 50 CORRIDOR. WITH THE INCREASING OROGRAPHIC FLOW AND UVV
AHEAD OF WAVE...SHOULD SEE SNOW INCREASING IN COVERAGE AND INTENSITY
ACROSS THE CENTRAL MTS MONDAY MORNING AND SPREADING EAST ACROSS THE
UPPER ARKANSAS RIVER VALLEY INTO THE PIKES PEAK REGION THROUGH THE
EARLY AFTERNOON. MODEL SOUNDINGS INDICATING LOWER ELEVATIONS RAPIDLY
SATURATING BEHIND FRONT WITH RAIN DEVELOPING ALONG AND BEHIND THE
FRONT. RAIN BECOMES MIXED WITH AND CHANGES TO SNOW LATE IN THE
AFTERNOON AND EARLY EVENING...ESPECIALLY ACROSS THE PALMER
DVD...WITH A POSSIBLE MESSY MONDAY EVENING COMMUTE. MODELS DIFFER ON
AMOUNT OF QPF ACROSS THE SE MTS MONDAY NIGHT THOUGH AGREE ON A BAND
OF MODERATE PRECIP DEVELOPING ACROSS THE CENTRAL MTS THROUGH THE
PIKES REGION MONDAY NIGHT THROUGH EARLY TUESDAY MORNING AS RRQUAD OF
JET TRANSLATES ACROSS SOUTH CENTRAL COLORADO. MAY NEED SOME
HIGHLIGHTS ACROSS THE CENTRAL MTS AND POSSIBLE THE PIKES PEAK REGION
IF LATEST MODELS REMAIN TRUE. COOL UPSLOPE FLOW PERSISTS ACROSS THE
PLAINS ON TUESDAY...WITH HIGHS WELL BELOW SEASONAL
AVERAGES...ESPECIALLY ACROSS THE EASTERN PLAINS.
WEDNESDAY-SATURDAY...A WARMING TREND TO NEAR SEASONAL AVERAGES
EXPECTED THROUGH THE PERIOD AS MODERATE NORTHWEST FLOW ALOFT
PERSISTS ACROSS THE REGION. A FEW EMBEDDED SHORT WAVE PROGGED TO
TRANSLATE THROUGH THE FLOW THURSDAY AND FRIDAY...OWNING TO A FEW
AFTERNOON AND EVENING SHOWERS ACROSS MAINLY THE HIGHER TERRAIN.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 312 PM MDT SAT APR 20 2013
UPPER WAVE OVER COLORADO WILL PRODUCE SHOWERS OVER THE HIGHER
TERRAIN UNTIL 03Z...AND PERIODS OF MVFR/IFR CONDITIONS MAY OCCUR
UNDER SOME OF THE HEAVIER PRECIPITATION. AT THE TAF SITES...KEPT A
MENTION OF VCSH AT KCOS AND KALS UNTIL 02Z-03Z...THOUGH WITH DRY LOW
LEVELS...SUSPECT WE`LL SEE MORE VIRGA AND GUSTY WINDS THAN ANY LOWER
CIGS/VIS. MAY ALSO SEE SOME -SHRA/VIRGA W/NW OF KPUB UNTIL 02Z...AND
GUSTY/ERRATIC WINDS WILL BE POSSIBLE AT THE TERMINAL THROUGH SUNSET.
VFR CONDITIONS RETURN TO ALL AREAS BY 06-09Z AS ANY SHOWERS
DISSIPATE. ON SUNDAY...VFR CONDITIONS EXPECTED MOST AREAS WITH ONLY
MINOR/ISOLATED LATE AFTERNOON -SHRA OVER THE MTS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR COZ060.
&&
$$
SHORT TERM...PETERSEN
LONG TERM...MW
AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1040 AM MDT SAT APR 20 2013
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 343 AM MDT SAT APR 20 2013
TODAY...SHORTWAVE AND ASSOCIATED SFC FRONT MAKING QUICK PROGRESS
ACROSS THE GREAT BASIN THIS MORNING AND WILL BE PUSHING EAST
ACROSS WESTERN COLORADO TODAY. AREAS OF LIGHT RAIN AND SNOW FALLING
ACROSS THE REGION WILL PEAK IN AREAL COVERAGE THIS MORNING AS THE
MAIN FORCING ASSOCIATED WITH THE PASSING WAVE ARRIVES. RADAR
ECHOES HAVE BEEN ON THE INCREASE THIS MORNING AND MORNING HRRR AND
RAP MODELS BOTH INDICATING A FAIRLY ACTIVE START TO THE DAY WITH
SNOW LEVELS RUNNING AROUND 6K. BEST ACCUMULATIONS LOOKS TO BE
CONFINED TO THE HIGHER ELEVATIONS...WITH THE NORTHERN MOUNTAINS
REMAINING FAVORED ATTM...WITH CURRENT ADVISORIES ON TRACK. HAVE
BOOSTED POPS AND SHAVED TEMPS A BIT FROM MOS VALUES.
TONIGHT...THOUGH DYNAMICAL SUPPORT HAS SHIFTED EAST SNOW WILL
CONTINUE ACROSS NW COLORADO WITH FORECAST SOUNDINGS INDICATING A
MOIST NW OROGRAPHIC FLOW THROUGH MIDNIGHT. THEN THE FLOW SLACKENS
SOMEWHAT AND BACKS TO SW. THE MOIST LAYER ALSO SHRINKS TO BELOW
12KFT FOR LITTLE TO NO ACCUMULATING SNOWFALL. TEMPERATURES STAY
NEAR NORMAL NORTH UNDER CLOUD COVER...ABOUT 5 DEGREES BELOW NORMAL
FOR THE CENTRAL AND SOUTH UNDER MOSTLY CLEAR SKIES.
SUNDAY...WEST WINDS INCREASE AS THE NEXT OPEN WAVE WORKS IN FROM THE
NW. THE JET REMAINS ORIENTED NEAR THE CO-WY BORDER EFFECTIVELY
KEEPING THE COLD AIR AND DYNAMICS NORTH OF THIS FORECAST AREA.
AFTERNOON HEATING AND MARGINAL MOISTURE PRODUCE A SLIVER OF
AFTERNOON CAPE MAINLY IN THE NW CO MTNS FOR SCATTERED SNOW SHOWERS.
SNOW LEVEL WILL BE AROUND 8KFT NORTH TO 9KFT CENTRAL.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 343 AM MDT SAT APR 20 2013
SUNDAY NIGHT-MONDAY NIGHT...ENHANCING ENERGY DEVELOPS A TROUGH AND
BEGINS TO PUSH THE JET AND ASSOCIATED COLD FRONT NW-SE THROUGH THE
REGION. THE BEST DYNAMICAL SUPPORT SHIFTS EAST OF THE CONTINENTAL
DIVIDE WITH SNOW ACCUMULATIONS NOW LOOKING MEAGER EXCEPT ALONG THE
COLORADO SPINE WHERE A CONVECTIVE COMPONENT MAY PRODUCE LOCALIZED
ENHANCED SNOW ACCUMULATIONS. BREEZY TO WINDY CONDITIONS CONTINUE ON
MONDAY AS THE COLD FRONT WORKS THROUGH THE REGION WITH A COOLER
DRIER AIR MASS WORKING IN OVERNIGHT.
TUESDAY THROUGH FRIDAY...EXITING WAVE WILL CLIP THE NORTHERN AND
CENTRAL MOUNTAINS WITH BRIEF PERIOD OF SNOWFALL ON TUESDAY. THE
ECMWF REMAINS A BIT STRONGER WITH THIS WAVE...WHICH WOULD RESULT
IN A BIT MORE ACTIVITY ACROSS THE FORECAST AREA. WILL SPLIT THE
DIFFERENCE AND KEEP HIGHER POPS CONFINED TO THE NORTHERN AND
CENTRAL MOUNTAINS. YET ANOTHER VERY WEAK SYSTEM BRUSHES BY ON
WEDNESDAY...BRINGING A SLIGHT CHANCE FOR HIGH MOUNTAIN SNOW
SHOWERS...OTHERWISE A DRY PERIOD IN STORE FROM TUESDAY NIGHT
THROUGH EARLY FRIDAY. THE GFS AND EC BOTH DRIVE ANOTHER SYSTEM
DOWN THE SPINE OF THE ROCKIES TO CLOSE OUT THE WEEK. THIS WOULD
BRING ANOTHER GLANCING SHOT OF PRECIPITATION TO THE
AREA...GENERALLY CONFINED TO THE NORTHERN ZONES. TEMPERATURES WILL
BE MODERATING A BIT THROUGH THE PERIOD...WITH READINGS CLIMBING TO
THE PLUS SIDE OF NORMAL AS WE CLOSE OUT THE WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1040 AM MDT SAT APR 20 2013
RAIN AND MOUNTAIN SNOW SHOWERS WILL CONTINUE OVER MUCH OF NORTHERN
AND CENTRAL CO AND THE SAN JUAN MOUNTAINS...WITH ISOLATED
PRECIPITATION OVER NE UTAH. MOST MOUNTAIN RANGES AND HIGH MOUNTAIN
PASSES WILL BE OBSCURED THROUGH THIS EVENING. SLOW IMPROVEMENT
WILL BEGIN BY 00Z THIS AFTERNOON WITH MORES STEADILY IMPROVING
CONDITIONS OVERNIGHT THROUGH SUNDAY. THROUGH THIS EVENING KASE...
KEGE...KRIL...KCAG...AND KHDN CAN EXPECT MVFR CIGS AND OCCASIONAL
MVFR VSBY IN PRECIP...WITH BRIEF PERIODS OF IFR CIGS AND VSBYS IN
STRONGER SHOWERS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR COZ004-
010-013.
UT...NONE.
&&
$$
SHORT TERM...JDC
LONG TERM...JOE
AVIATION...CC
AREA FORECAST DISCUSSION...CORRECTED
NWS GRAND JUNCTION CO
414 AM MDT SAT APR 20 2013
CORRECTED TIMING OF AVIATION SECTION
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 343 AM MDT SAT APR 20 2013
TODAY...SHORTWAVE AND ASSOCIATED SFC FRONT MAKING QUICK PROGRESS
ACROSS THE GREAT BASIN THIS MORNING AND WILL BE PUSHING EAST
ACROSS WESTERN COLORADO TODAY. AREAS OF LIGHT RAIN AND SNOW FALLING
ACROSS THE REGION WILL PEAK IN AREAL COVERAGE THIS MORNING AS THE
MAIN FORCING ASSOCIATED WITH THE PASSING WAVE ARRIVES. RADAR
ECHOES HAVE BEEN ON THE INCREASE THIS MORNING AND MORNING HRRR AND
RAP MODELS BOTH INDICATING A FAIRLY ACTIVE START TO THE DAY WITH
SNOW LEVELS RUNNING AROUND 6K. BEST ACCUMULATIONS LOOKS TO BE
CONFINED TO THE HIGHER ELEVATIONS...WITH THE NORTHERN MOUNTAINS
REMAINING FAVORED ATTM...WITH CURRENT ADVISORIES ON TRACK. HAVE
BOOSTED POPS AND SHAVED TEMPS A BIT FROM MOS VALUES.
TONIGHT...THOUGH DYNAMICAL SUPPORT HAS SHIFTED EAST SNOW WILL
CONTINUE ACROSS NW COLORADO WITH FORECAST SOUNDINGS INDICATING A
MOIST NW OROGRAPHIC FLOW THROUGH MIDNIGHT. THEN THE FLOW SLACKENS
SOMEWHAT AND BACKS TO SW. THE MOIST LAYER ALSO SHRINKS TO BELOW
12KFT FOR LITTLE TO NO ACCUMULATING SNOWFALL. TEMPERATURES STAY
NEAR NORMAL NORTH UNDER CLOUD COVER...ABOUT 5 DEGREES BELOW NORMAL
FOR THE CENTRAL AND SOUTH UNDER MOSTLY CLEAR SKIES.
SUNDAY...WEST WINDS INCREASE AS THE NEXT OPEN WAVE WORKS IN FROM THE
NW. THE JET REMAINS ORIENTED NEAR THE CO-WY BORDER EFFECTIVELY
KEEPING THE COLD AIR AND DYNAMICS NORTH OF THIS FORECAST AREA.
AFTERNOON HEATING AND MARGINAL MOISTURE PRODUCE A SLIVER OF
AFTERNOON CAPE MAINLY IN THE NW CO MTNS FOR SCATTERED SNOW SHOWERS.
SNOW LEVEL WILL BE AROUND 8KFT NORTH TO 9KFT CENTRAL.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 343 AM MDT SAT APR 20 2013
SUNDAY NIGHT-MONDAY NIGHT...ENHANCING ENERGY DEVELOPS A TROUGH AND
BEGINS TO PUSH THE JET AND ASSOCIATED COLD FRONT NW-SE THROUGH THE
REGION. THE BEST DYNAMICAL SUPPORT SHIFTS EAST OF THE CONTINENTAL
DIVIDE WITH SNOW ACCUMULATIONS NOW LOOKING MEAGER EXCEPT ALONG THE
COLORADO SPINE WHERE A CONVECTIVE COMPONENT MAY PRODUCE LOCALIZED
ENHANCED SNOW ACCUMULATIONS. BREEZY TO WINDY CONDITIONS CONTINUE ON
MONDAY AS THE COLD FRONT WORKS THROUGH THE REGION WITH A COOLER
DRIER AIR MASS WORKING IN OVERNIGHT.
TUESDAY THROUGH FRIDAY...EXITING WAVE WILL CLIP THE NORTHERN AND
CENTRAL MOUNTAINS WITH BRIEF PERIOD OF SNOWFALL ON TUESDAY. THE
ECMWF REMAINS A BIT STRONGER WITH THIS WAVE...WHICH WOULD RESULT
IN A BIT MORE ACTIVITY ACROSS THE FORECAST AREA. WILL SPLIT THE
DIFFERENCE AND KEEP HIGHER POPS CONFINED TO THE NORTHERN AND
CENTRAL MOUNTAINS. YET ANOTHER VERY WEAK SYSTEM BRUSHES BY ON
WEDNESDAY...BRINGING A SLIGHT CHANCE FOR HIGH MOUNTAIN SNOW
SHOWERS...OTHERWISE A DRY PERIOD IN STORE FROM TUESDAY NIGHT
THROUGH EARLY FRIDAY. THE GFS AND EC BOTH DRIVE ANOTHER SYSTEM
DOWN THE SPINE OF THE ROCKIES TO CLOSE OUT THE WEEK. THIS WOULD
BRING ANOTHER GLANCING SHOT OF PRECIPITATION TO THE
AREA...GENERALLY CONFINED TO THE NORTHERN ZONES. TEMPERATURES WILL
BE MODERATING A BIT THROUGH THE PERIOD...WITH READINGS CLIMBING TO
THE PLUS SIDE OF NORMAL AS WE CLOSE OUT THE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY NIGHT)
ISSUED AT 343 AM MDT SAT APR 20 2013
WIDESPREAD RAIN AND SNOW SHOWERS WILL OCCUR THROUGH THIS
AFTERNOON...WITH MOUNTAINS FQTLY OBSCD. EXPECT AREAS OF MVFR CIGS
AND VSBYS...WITH LOCAL IFR CONDITIONS AS THE SHOWERS PASS THROUGH.
SLOW IMPROVEMENT WILL OCCUR FROM WEST TO EAST AFTER 21Z THIS
AFTERNOON...ALTHOUGH AREAS NEAR THE DIVIDE WILL CONTINUE TO BE
IMPACTED THROUGH 06Z SUNDAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR COZ004-
010-013.
UT...NONE.
&&
$$
SHORT TERM...JDC
LONG TERM...JOE
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
344 AM MDT SAT APR 20 2013
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 343 AM MDT SAT APR 20 2013
TODAY...SHORTWAVE AND ASSOCIATED SFC FRONT MAKING QUICK PROGRESS
ACROSS THE GREAT BASIN THIS MORNING AND WILL BE PUSHING EAST
ACROSS WESTERN COLORADO TODAY. AREAS OF LIGHT RAIN AND SNOW FALLING
ACROSS THE REGION WILL PEAK IN AREAL COVERAGE THIS MORNING AS THE
MAIN FORCING ASSOCIATED WITH THE PASSING WAVE ARRIVES. RADAR
ECHOES HAVE BEEN ON THE INCREASE THIS MORNING AND MORNING HRRR AND
RAP MODELS BOTH INDICATING A FAIRLY ACTIVE START TO THE DAY WITH
SNOW LEVELS RUNNING AROUND 6K. BEST ACCUMULATIONS LOOKS TO BE
CONFINED TO THE HIGHER ELEVATIONS...WITH THE NORTHERN MOUNTAINS
REMAINING FAVORED ATTM...WITH CURRENT ADVISORIES ON TRACK. HAVE
BOOSTED POPS AND SHAVED TEMPS A BIT FROM MOS VALUES.
TONIGHT...THOUGH DYNAMICAL SUPPORT HAS SHIFTED EAST SNOW WILL
CONTINUE ACROSS NW COLORADO WITH FORECAST SOUNDINGS INDICATING A
MOIST NW OROGRAPHIC FLOW THROUGH MIDNIGHT. THEN THE FLOW SLACKENS
SOMEWHAT AND BACKS TO SW. THE MOIST LAYER ALSO SHRINKS TO BELOW
12KFT FOR LITTLE TO NO ACCUMULATING SNOWFALL. TEMPERATURES STAY
NEAR NORMAL NORTH UNDER CLOUD COVER...ABOUT 5 DEGREES BELOW NORMAL
FOR THE CENTRAL AND SOUTH UNDER MOSTLY CLEAR SKIES.
SUNDAY...WEST WINDS INCREASE AS THE NEXT OPEN WAVE WORKS IN FROM THE
NW. THE JET REMAINS ORIENTED NEAR THE CO-WY BORDER EFFECTIVELY
KEEPING THE COLD AIR AND DYNAMICS NORTH OF THIS FORECAST AREA.
AFTERNOON HEATING AND MARGINAL MOISTURE PRODUCE A SLIVER OF
AFTERNOON CAPE MAINLY IN THE NW CO MTNS FOR SCATTERED SNOW SHOWERS.
SNOW LEVEL WILL BE AROUND 8KFT NORTH TO 9KFT CENTRAL.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 343 AM MDT SAT APR 20 2013
SUNDAY NIGHT-MONDAY NIGHT...ENHANCING ENERGY DEVELOPS A TROUGH AND
BEGINS TO PUSH THE JET AND ASSOCIATED COLD FRONT NW-SE THROUGH THE
REGION. THE BEST DYNAMICAL SUPPORT SHIFTS EAST OF THE CONTINENTAL
DIVIDE WITH SNOW ACCUMULATIONS NOW LOOKING MEAGER EXCEPT ALONG THE
COLORADO SPINE WHERE A CONVECTIVE COMPONENT MAY PRODUCE LOCALIZED
ENHANCED SNOW ACCUMULATIONS. BREEZY TO WINDY CONDITIONS CONTINUE ON
MONDAY AS THE COLD FRONT WORKS THROUGH THE REGION WITH A COOLER
DRIER AIR MASS WORKING IN OVERNIGHT.
TUESDAY THROUGH FRIDAY...EXITING WAVE WILL CLIP THE NORTHERN AND
CENTRAL MOUNTAINS WITH BRIEF PERIOD OF SNOWFALL ON TUESDAY. THE
ECMWF REMAINS A BIT STRONGER WITH THIS WAVE...WHICH WOULD RESULT
IN A BIT MORE ACTIVITY ACROSS THE FORECAST AREA. WILL SPLIT THE
DIFFERENCE AND KEEP HIGHER POPS CONFINED TO THE NORTHERN AND
CENTRAL MOUNTAINS. YET ANOTHER VERY WEAK SYSTEM BRUSHES BY ON
WEDNESDAY...BRINGING A SLIGHT CHANCE FOR HIGH MOUNTAIN SNOW
SHOWERS...OTHERWISE A DRY PERIOD IN STORE FROM TUESDAY NIGHT
THROUGH EARLY FRIDAY. THE GFS AND EC BOTH DRIVE ANOTHER SYSTEM
DOWN THE SPINE OF THE ROCKIES TO CLOSE OUT THE WEEK. THIS WOULD
BRING ANOTHER GLANCING SHOT OF PRECIPITATION TO THE
AREA...GENERALLY CONFINED TO THE NORTHERN ZONES. TEMPERATURES WILL
BE MODERATING A BIT THROUGH THE PERIOD...WITH READINGS CLIMBING TO
THE PLUS SIDE OF NORMAL AS WE CLOSE OUT THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 343 AM MDT SAT APR 20 2013
WIDESPREAD RAIN AND SNOW SHOWERS WILL OCCUR THROUGH THIS
AFTERNOON...WITH MOUNTAINS FQTLY OBSCD. EXPECT AREAS OF MVFR CIGS
AND VSBYS...WITH LOCAL IFR CONDITIONS AS THE SHOWERS PASS THROUGH.
SLOW IMPROVEMENT WILL OCCUR FROM WEST TO EAST AFTER 21Z THIS
AFTERNOON...ALTHOUGH AREAS NEAR THE DIVIDE WILL CONTINUE TO BE
IMPACTED THROUGH 06Z SUNDAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR COZ004-
010-013.
UT...NONE.
&&
$$
SHORT TERM...JDC
LONG TERM...JOE
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS TAUNTON MA
428 AM EDT SAT APR 20 2013
.SYNOPSIS...
WIDESPREAD RAIN WITH EMBEDDED HEAVIER SHOWERS WILL CONTINUE INTO
THE MORNING HOURS AS A COLD FRONT GRADUALLY SWEEPS ACROSS THE AREA
AND OFFSHORE. STRONG SOUTHERLY WINDS WITH GUSTS UP TO 35 MPH CAN
BE EXPECTED AHEAD OF THE FRONT...BACKING OUT OF THE WEST IN WAKE
WITH CONTINUED GUSTS AROUND 25 MPH. COLDER AND DRIER AIR WILL
ADVECT INTO THE REGION FOR THE REMAINDER OF THIS WEEKEND INTO THE
EARLY PART OF NEXT WEEK. A DEVELOPING COASTAL STORM WILL BRING
SHOWERS AROUND TUESDAY...THEN ANOTHER COLD FRONT MOVES THROUGH
LATER IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
INTO THE MORNING...
WIDESPREAD RAIN CONTINUES WITH EMBEDDED HEAVIER SHOWERS. HAVE
REMOVED ALL MENTION OF THUNDER. WINDS HAVE BEGUN TO SLACKEN LIKELY
AS A RESULT OF BOUNDARY LAYER DECOUPLING. GUSTS UP TO 35 MPH ARE
ONLY ANTICIPATED ACROSS THE SOUTHEASTERN FORECAST AREA AND ACROSS
THE ADJACENT WATERS. CONTINUED BLEND OF NEAR-TERM MESOSCALE
GUIDANCE OF THE WRF AND RAP HAS DONE IMPRESSIVELY WELL IN HANDLING
THE PARTICULAR OUTCOMES.
TODAY...
SHOWERS AND CLOUDS LINGER ACROSS SOUTHEASTERN MASSACHUSETTS AND THE
ADJACENT WATERS DURING THE MORNING HOURS...GRADUALLY CLEARING INTO
MIDDAY. SOUTHWEST GUSTS CONTINUING AHEAD OF THE FRONT BACKING OUT
OF THE WEST AND USHERING COOLER AND DRIER AIR INTO THE REGION
ASSOCIATED WITH HIGH PRESSURE. THIS WILL ALLOW THE BOUNDARY LAYER
TO BECOME WELL-MIXED UP TO H8 ALLOWING THE MIX-DOWN OF DRIER AIR
AND FASTER MOMENTUM. SO THE EXPECTATION FOR THE DAY IS HIGHS
AROUND THE UPPER 50S TO LOW 60S WITH WESTERLY WINDS GUSTING AROUND
25 MPH. SHOULD SEE A MIX-OUT OF RESIDUAL MOISTURE OF THE PREVIOUS
EVENINGS RAINS ALLOWING FOR SCATTERED TO BROKEN DIURNAL CUMULUS.
THIS COULD POTENTIAL HAVING ADVERSE AFFECT ON SURFACE TEMPERATURES
RESULTING IN COOLER VALUES THAN PRESENTLY FORECAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
TONIGHT...
WEST-NORTHWEST FLOW CONTINUING YET GRADUALLY DYING DOWN AS
CONDITIONS GRADUALLY CLEAR. EXPECTING TEMPERATURES TO FALL DOWN TO
THE FREEZING MARK WITH LOWS INTO THE UPPER 20S ACROSS THE CENTRAL
INTERIOR AND HIGHER ELEVATIONS. SHOULD SHELTERED VALLEY LOCALES
BECOME CALM...THERE IS THE POTENTIAL FOR EFFECTIVE RADIATIONAL
COOLING ALLOWING COLDER CONDITIONS. THE EXPECTATION FOR IS A VERY
DRY COLUMN EARLIER IN THE DAY CONTINUING OVERNIGHT...SO HAVE LOW
EXPECTATIONS FOR FOG.
SUNDAY...
HIGH PRESSURE IN CONTROL WITH MOSTLY CLEAR CONDITIONS. LIGHT AND
VARIABLE WINDS UNDER A CONTINUED COOL AND DRY AIRMASS. ANTICIPATING
SEA-BREEZES ALONG THE IMMEDIATE SHORES AS HIGHS WILL GET UP INTO THE
MID TO UPPER 50S /COOLER ALONG THE SHORES CONSEQUENTIAL OF SEA-
BREEZES/.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
BIG PICTURE...
UPPER RIDGE SHIFTS OVER THE WESTERN ATLANTIC. SECOND UPPER RIDGE
TAKES UP POSITION OFF THE PACIFIC COAST. THIS MAKES ROOM FOR A
BROAD TROUGH TO DIG OVER THE INTERIOR USA. A SHORTWAVE IN THIS
BROAD FLOW MOVES FROM THE PACIFIC NORTHWEST TO THE SOUTHERN USA
OVER THIS WEEKEND...THEN GENERATES A INVERTED TROUGH AT THE
SURFACE OFF THE CAROLINA COAST. THIS FULL COMPLEX MOVES PAST NEW
ENGLAND WEDNESDAY. ANOTHER BETTER DEFINED SHORTWAVE DIVES SOUTH
FROM NORTHERN CANADA INTO THE INTERIOR USA TROUGH AND THEN SWINGS
ACROSS NEW ENGLAND LATE NEXT WEEK.
UPPER JET OVER NEW ENGLAND MOVES NORTHEAST PAST GREENLAND/ICELAND.
ANOTHER JET SEGMENT TRACES THE PACIFIC NORTHWEST/SOUTHERN ROCKIES.
THIS EVENTUALLY SWINGS NORTHEAST THROUGH THE GREAT LAKES MIDWEEK
AND THE NORTHEAST USA LATE WEEK.
MODEL PREFERENCES...
SMALL DIFFERENCE IN GFS AND ECMWF UPPER CONTOUR FIELDS REGARDING
COASTAL SYSTEM NEXT WEEK. OTHERWISE THE LONG RANGE MODELS ARE IN
GOOD AGREEMENT SURFACE AND ALOFT. WE USED A BLEND OF 20/00Z
GFS/ECMWF VALUES...AND BLEND WITH GRIDDED MOS/HPC GRIDS WHERE
AVAILABLE.
THE DAILIES...
SUNDAY NIGHT-MONDAY...
HIGH PRESSURE MOVES OFFSHORE MONDAY. GENERALLY FAIR WEATHER WITH
INCREASING CIRRUS DURING MONDAY. TEMPERATURES ALOFT RISE A LITTLE
MONDAY...BUT THE BUFFERING OF THE INCREASED EAST FLOW SHOULD
BALANCE ANY WARMING AND KEEP HIGH TEMPERATURES SIMILAR TO SUNDAY.
MONDAY NIGHT-TUESDAY...
INVERTED TROUGH/DEVELOPING COASTAL LOW WILL START PUSHING DEEPER
MOISTURE UP THE COAST. ALL MODEL PRECIPITATION FORECASTS ARE WELL
SOUTH OF NEW ENGLAND MONDAY EVENING...BUT MOVE MEASURABLE PCPN
INTO THE AREA...ESPECIALLY THE SOUTH COAST...AFTER 06Z/2 AM.
20/00Z GFS IS FARTHER EAST THAN THE OTHER MEMBERS OF THE 20/00Z
GUIDANCE SUITE. THIS LOOKS SUSPICIOUS WITH SUCH A STRONG HIGH
PRESSURE ANCHORED OVER THE MARITIMES. AS SUCH...FAVORED THE MORE
WESTERN CONSENSUS TRACK LED BY THE ECMWF. BASED ON THAT TRACK...
INCREASED POPS TO LIKELY ACROSS EASTERN MA TUESDAY...WITH CHANCE
POPS TUESDAY NIGHT AS THIS SYSTEM PULLS AWAY.
WEDNESDAY-THURSDAY...
PLAINS/GREAT LAKES TROUGH AND SUPPORTING UPPER JET MOVE UP THE ST
LAWRENCE VALLEY INTO CANADA. THIS FEATURE WILL SUPPORT A COLD
FRONT THAT WILL SWING THROUGH NEW ENGLAND WEDNESDAY NIGHT-
THURSDAY. ON WEDNESDAY POPS SHOW A BRIEF BREAK AFTER A COASTAL
SYSTEM MOVES OFF...BUT THEN A RESUMPTION OF CHANCE POPS AS THE
GREAT LAKES COLD FRONT MOVES THROUGH. THE DEPICTION OF TWO
DISTINCT SYSTEMS IS REASONABLE GIVEN THAT ONE IS SOUTHERN STREAM
AND THE OTHER IS NORTHERN STREAM...BUT THE DISTINCTNESS/LENGTH OF
TIME BETWEEN THE TWO PCPN SHIELDS IS LESS CERTAIN.
FRIDAY...
HIGH PRESSURE BUILDS AT THE SURFACE WHILE THE SUPPORTING UPPER
TROUGH FROM THURSDAY/S FRONT WILL STILL BE IN THE NEIGHBORHOOD. NO
DESTABILIZATION EXPECTED AS UPPER TEMPERATURES SHOW LITTLE CHANGE
AND MOISTURE IS LIMITED. EXPECTING A DRY DAY WITH SIMILAR MAX/MIN
TEMPERATURES TO THURSDAY.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...
* MODERATE CONFIDENCE INTO SATURDAY MORNING...
* HIGH CONFIDENCE SATURDAY AFTERNOON INTO SUNDAY...
A MIX OF MVFR-IFR CIGS AND VSBYS CONTINUE WITH THE BROAD AREA OF
RAIN WITH EMBEDDED HEAVIER SHOWERS. ALREADY BEGINNING TO SEE WINDS
BACKING OUT OF THE WEST-NORTHWEST WITH THE COLD FRONTAL PASSAGE
INTO THE CONNECTICUT RIVER VALLEY...THOUGH CIGS ARE SLOW TO LIFT.
WHILE DIFFICULTIES PERSIST IN TIMING OF IMPROVEMENT WEST TO
EAST...HAVE CONFIDENCE CONCERNING THE OVERALL TREND THAT VSBYS
WILL QUICKLY IMPROVE BEHIND THE COLD FRONT AND CIGS WILL GRADUALLY
LIFT. WINDS WILL BACK OUT OF THE WEST-NORTHWEST WITH GUSTS UP TO
25 KTS WITH SCT-BKN DIURNAL CU DURING TODAY. IMPROVING TO VFR.
INTO THE EVENING AND ON INTO SUNDAY...WINDS SHOULD BECOME LIGHT
AND VARIABLE. SEA-BREEZE LIKELY TO IMPACT COASTAL TERMINALS. WILL
NEED TO MONITOR CLOSELY FOR THE DEVELOPMENT OF FOG OVERNIGHT IN
LOW LYING LOCATIONS AS MUCH COLDER AIR SETTLES INTO THE REGION.
MOSTLY CLEAR CONDITIONS. VFR.
KBOS TERMINAL...MODERATE CONFIDENCE.
WHILE FAIRLY CERTAIN ON TRENDS...THE TIMING OF IMPACTS OVER THE
NEXT SEVERAL HOURS COUPLED WITH IMPROVEMENT REMAINS CHALLENGING.
COULD SEE SEA-BREEZE IMPACTS ON SUNDAY.
KBDL TERMINAL...MODERATE CONFIDENCE.
GRADUAL IMPROVEMENT SHOULD BEGIN AS THE COLD FRONT HAS SWEPT
ACROSS THE TERMINAL...THE TIMING OF WHICH REMAINS TRICKY. COULD
SEE SOME FOG IMPACTS SATURDAY NIGHT INTO SUNDAY MORNING.
OUTLOOK...SUNDAY THROUGH WEDNESDAY...
SUNDAY NIGHT-MONDAY...VFR. LIGHT WINDS SUNDAY NIGHT. INCREASING
EAST WINDS MONDAY WITH GUSTS TO 25 KNOTS ALONG THE CAPE AND
ISLANDS/SOUTH COAST. HIGH CONFIDENCE.
MONDAY NIGHT-TUESDAY...CONDITIONS LOWERING LATER MONDAY NIGHT
WITH MVFR/IFR CIGS/VSBY POSSIBLE TUESDAY ESPECIALLY RI AND
SOUTHEAST MASS. MODERATE CONFIDENCE.
WEDNESDAY...CONDITIONS IMPROVING TO VFR DURING THE MORNING AND
AFTERNOON AS TUESDAY/S STORM MOVES OFF. A COLD FRONT APPROACHES
LATE IN THE DAY...BUT EFFECTS MAY HOLD OFF UNTIL WEDNESDAY NIGHT
WHEN CONDITIONS MAY LOWER TO MVFR/IFR IN SHOWERS/SCATTERED TSTMS.
MODERATE CONFIDENCE.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...MODERATE CONFIDENCE THROUGH SUNDAY.
GALE WARNINGS WILL CONTINUE FOR A BRIEF PERIOD THIS MORNING...
REVERTING TO SMALL CRAFT ADVISORIES AS WINDS GRADUALLY RELAX BELOW
35 KTS.
THE EXPECTATION IS FOR WESTERLY FLOW BEHIND A COLD FRONT WHICH WILL
SWEEP ACROSS THE WATERS THIS MORNING INTO MIDDAY TO GUST UP TO 25
KTS AND KEEP SEAS IN EXCESS OF 5 FEET /UP TO 10 FEET ON THE OUTER
WATERS/. ANTICIPATE WIDESPREAD RAIN WITH EMBEDDED HEAVIER SHOWERS
RESULTING IN SOME MINOR VISIBILITY IMPACTS AHEAD OF THE COLD FRONT.
WINDS AND SEAS ARE ANTICIPATED TO FALL BELOW SMALL CRAFT ADVISORY
THRESHOLDS ON SUNDAY AS HIGH PRESSURE SETTLES ACROSS THE REGION.
OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY...
HIGH CONFIDENCE SUNDAY TO TUESDAY. MODERATE CONFIDENCE WEDNESDAY.
MONDAY...INCREASING EAST WIND WITH POTENTIAL WIND GUSTS TO 25 KT
AND SEAS 5 FEET OR HIGHER IN THE AFTERNOON AND AT NIGHT...
ESPECIALLY ACROSS THE SOUTHERN WATERS. SMALL CRAFT ADVISORIES
LIKELY...ESPECIALLY FOR THE OUTER COASTAL WATERS.
TUESDAY...SEAS AT OR ABOVE 5 FEET ACROSS THE OPEN WATERS. EAST
WINDS GUSTING AROUND 25 KT. SMALL CRAFT ADVISORIES LIKELY.
WEDNESDAY...A SHORT BREAK BETWEEN WEATHER SYSTEMS. WINDS GENERALLY
BELOW 25 KT...BUT MAY INCREASE TO NEAR 25 KT ACROSS THE EASTERN
WATERS LATE IN THE DAY. SEAS UP TO 7 FEET...MAINLY ACROSS THE
OUTER WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...GALE WARNING UNTIL 6 AM EDT EARLY THIS MORNING FOR ANZ231>234-
250-251.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR ANZ230-
236.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT SUNDAY FOR ANZ235-237.
GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR ANZ254-255.
SMALL CRAFT ADVISORY UNTIL 2 PM EDT SUNDAY FOR ANZ256.
&&
$$
SYNOPSIS...SIPPRELL/BELK
NEAR TERM...SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...BELK
AVIATION...SIPPRELL/BELK
MARINE...SIPPRELL/BELK
AREA FORECAST DISCUSSION
NWS TAUNTON MA
341 AM EDT SAT APR 20 2013
.SYNOPSIS...
WIDESPREAD RAIN WITH EMBEDDED HEAVIER SHOWERS WILL CONTINUE INTO
THE MORNING HOURS AS A COLD FRONT GRADUALLY SWEEPS ACROSS THE AREA
AND OFFSHORE. STRONG SOUTHERLY WINDS WITH GUSTS UP TO 35 MPH CAN
BE EXPECTED AHEAD OF THE FRONT...BACKING OUT OF THE WEST IN WAKE
WITH CONTINUED GUSTS AROUND 25 MPH. COLDER AND DRIER AIR WILL
ADVECT INTO THE REGION FOR THE REMAINDER OF THE WEEKEND INTO THE
EARLY PART OF NEXT WEEK. A DEVELOPING COASTAL STORM WILL BRING
SHOWERS AROUND TUESDAY...THEN ANOTHER COLD FRONT MOVES THROUGH
LATER IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
INTO THE MORNING...
WIDESPREAD RAIN CONTINUES WITH EMBEDDED HEAVIER SHOWERS. HAVE
REMOVED ALL MENTION OF THUNDER. WINDS HAVE BEGUN TO SLACKEN LIKELY
AS A RESULT OF BOUNDARY LAYER DECOUPLING. GUSTS UP TO 35 MPH ARE
ONLY ANTICIPATED ACROSS THE SOUTHEASTERN FORECAST AREA AND ACROSS
THE ADJACENT WATERS. CONTINUED BLEND OF NEAR-TERM MESOSCALE
GUIDANCE OF THE WRF AND RAP HAS DONE IMPRESSIVELY WELL IN HANDLING
THE PARTICULAR OUTCOMES.
TODAY...
SHOWERS AND CLOUDS LINGER ACROSS SOUTHEASTERN MASSACHUSETTS AND THE
ADJACENT WATERS DURING THE MORNING HOURS...GRADUALLY CLEARING INTO
MIDDAY. SOUTHWEST GUSTS CONTINUING AHEAD OF THE FRONT BACKING OUT
OF THE WEST AND USHERING COOLER AND DRIER AIR INTO THE REGION
ASSOCIATED WITH HIGH PRESSURE. THIS WILL ALLOW THE BOUNDARY LAYER
TO BECOME WELL-MIXED UP TO H8 ALLOWING THE MIX-DOWN OF DRIER AIR
AND FASTER MOMENTUM. SO THE EXPECTATION FOR THE DAY IS HIGHS
AROUND THE UPPER 50S TO LOW 60S WITH WESTERLY WINDS GUSTING AROUND
25 MPH. SHOULD SEE A MIX-OUT OF RESIDUAL MOISTURE OF THE PREVIOUS
EVENINGS RAINS ALLOWING FOR SCATTERED TO BROKEN DIURNAL CUMULUS.
THIS COULD POTENTIAL HAVING ADVERSE AFFECT ON SURFACE TEMPERATURES
RESULTING IN COOLER VALUES THAN PRESENTLY FORECAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
TONIGHT...
WEST-NORTHWEST FLOW CONTINUING YET GRADUALLY DYING DOWN AS
CONDITIONS GRADUALLY CLEAR. EXPECTING TEMPERATURES TO FALL DOWN TO
THE FREEZING MARK WITH LOWS INTO THE UPPER 20S ACROSS THE CENTRAL
INTERIOR AND HIGHER ELEVATIONS. SHOULD SHELTERED VALLEY LOCALES
BECOME CALM...THERE IS THE POTENTIAL FOR EFFECTIVE RADIATIONAL
COOLING ALLOWING COLDER CONDITIONS. THE EXPECTATION FOR IS A VERY
DRY COLUMN EARLIER IN THE DAY CONTINUING OVERNIGHT...SO HAVE LOW
EXPECTATIONS FOR FOG.
SUNDAY...
HIGH PRESSURE IN CONTROL WITH MOSTLY CLEAR CONDITIONS. LIGHT AND
VARIABLE WINDS UNDER A CONTINUED COOL AND DRY AIRMASS. ANTICIPATING
SEA-BREEZES ALONG THE IMMEDIATE SHORES AS HIGHS WILL GET UP INTO THE
MID TO UPPER 50S /COOLER ALONG THE SHORES CONSEQUENTIAL OF SEA-
BREEZES/.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
BIG PICTURE...
UPPER RIDGE SHIFTS OVER THE WESTERN ATLANTIC. SECOND UPPER RIDGE
TAKES UP POSITION OFF THE PACIFIC COAST. THIS MAKES ROOM FOR A
BROAD TROUGH TO DIG OVER THE INTERIOR USA. SHORTWAVE IN THIS BROAD
FLOW MOVES FROM THE PACIFIC NORTHWEST TO THE SOUTHERN USA OVER THE
WEEKEND...THEN GENERATES A INVERTED TROUGH AT THE SURFACE OFF THE
CAROLINA COAST. THE FULL COMPLEX MOVES PAST NEW ENGLAND WEDNESDAY.
ANOTHER BETTER DEFINED SHORTWAVE DIVES SOUTH FROM NORTHERN CANADA
INTO THE INTERIOR USA TROUGH AND THEN SWINGS ACROSS NEW ENGLAND
LATE WEEK.
UPPER JET OVER NEW ENGLAND MOVES NORTHEAST PAST GREENLAND/ICELAND.
ANOTHER JET SEGMENT TRACES THE PACIFIC NORTHWEST/SOUTHERN
ROCKIES...THIS EVENTUALLY SWINGS NORTHEAST THROUGH THE GREAT LAKES
MIDWEEK AND THE NORTHEAST USA LATE WEEK.
MODEL PREFERENCES...
SMALL DIFFERENCE IN GFS AND ECMWF UPPER CONTOUR FIELDS REGARDING
COASTAL SYSTEM NEXT WEEK. OTHERWISE THE LONG RANGE MODELS ARE IN
GOOD AGREEMENT SURFACE AND ALOFT. WE USED A BLEND OF GFS/ECMWF
VALUES...AND BLEND WITH GMOS/HPC GRIDS WHERE AVAILABLE.
THE DAILIES...
SUNDAY-MONDAY...
HIGH PRESSURE BUILDS OVER THE REGION SUNDAY AND THEN MOVES
OFFSHORE MONDAY. GENERALLY FAIR WEATHER WITH INCREASING CIRRUS
DURING MONDAY. AS WIND FIELDS LIGHTEN SUNDAY AFTERNOON THERE WILL
BE THE POTENTIAL FOR A SEA BREEZE. THE OVERALL GRADIENT FLOW THEN
SUPPORTS AN EAST FLOW ON MONDAY. TEMPS IN THE MIXED LAYER WILL BE
-3C TO -5C SUNDAY WHICH WOULD SUPPORT 50S AT THE SURFACE. CLEAR
SKIES AND LIGHT WINDS WILL ALLOW RADIATIONAL COOLING SUNDAY
NIGHT...WITH DEWPOINTS IN THE 20S THAT SHOULD ALLOW FOR MIN TEMPS
IN THE 20S AND LOWER 30S EXCEPT A LITTLE MILDER ALONG THE COAST.
TEMPS ALOFT WARM A LITTLE ON MONDAY...BUT THE BUFFERING OF THE
INCREASED EAST FLOW SHOULD BALANCE OFF ANY WARMING.
MONDAY NIGHT-TUESDAY...
INVERTED TROUGH/DEVELOPING COASTAL LOW WILL START PUSHING DEEPER
MOISTURE UP THE COAST. ALL MODEL PCPN FORECASTS ARE WELL SOUTH OF
NEW ENGLAND MONDAY EVENING BUT MOVE MEASURABLE PCPN INTO THE
AREA...ESPECIALLY THE SOUTH COAST...AFTER 06Z/2AM. WE SLOWED THE
HOURLY POP VALUES A FEW HOURS BASED ON THIS MODEL AGREEMENT. NEW
ENGLAND IS IN THE RIGHT ENTRANCE REGION OF THE DEPARTING UPPER JET
THROUGH TUESDAY SO DEVELOPMENT AND PCPN ARE REASONABLE. CHANCE
POPS UNTIL THE SURFACE LOW/UPPER SHORTWAVE MOVE PAST ON TUESDAY
NIGHT.
WEDNESDAY-THURSDAY...
PLAINS/GREAT LAKES TROUGH AND SUPPORTING UPPER JET MOVE UP THE ST
LAWRENCE VALLEY INTO CANADA. THIS FEATURE WILL SUPPORT A COLD
FRONT THAT WILL SWING THROUGH NEW ENGLAND WEDNESDAY NIGHT-
THURSDAY. ON WEDNESDAY POPS SHOW A BREAK AFTER THE COASTAL SYSTEM
MOVES OFF...BUT THEN A RESUMPTION OF CHANCE POPS AS THE GREAT
LAKES COLD FRONT MOVES THROUGH. THE DEPICTION OF TWO DISTINCT
SYSTEMS IS REASONABLE GIVEN THAT ONE IS SOUTHERN STREAM AND THE
OTHER IS NORTHERN STREAM...BUT THE DISTINCTNESS/LENGTH OF TIME
BETWEEN THE TWO PCPN SHIELDS IS LESS CERTAIN.
FRIDAY...
HIGH PRESSURE BUILDS AT THE SURFACE WHILE THE SUPPORTING UPPER
TROUGH FROM THURSDAY/S FRONT WILL STILL BE IN THE NEIGHBORHOOD. NO
DESTABILIZING EXPECTED AS UPPER TEMPS SHOW LITTLE CHANGE AND
MOISTURE IS LIMITED. EXPECT A DRY DAY WITH SIMILAR MAX/MIN TEMPS.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...
* MODERATE CONFIDENCE INTO SATURDAY MORNING...
* HIGH CONFIDENCE SATURDAY AFTERNOON INTO SUNDAY...
A MIX OF MVFR-IFR CIGS AND VSBYS CONTINUE WITH THE BROAD AREA OF
RAIN WITH EMBEDDED HEAVIER SHOWERS. ALREADY BEGINNING TO SEE WINDS
BACKING OUT OF THE WEST-NORTHWEST WITH THE COLD FRONTAL PASSAGE
INTO THE CONNECTICUT RIVER VALLEY...THOUGH CIGS ARE SLOW TO LIFT.
WHILE DIFFICULTIES PERSIST IN TIMING OF IMPROVEMENT WEST TO
EAST...HAVE CONFIDENCE CONCERNING THE OVERALL TREND THAT VSBYS
WILL QUICKLY IMPROVE BEHIND THE COLD FRONT AND CIGS WILL GRADUALLY
LIFT. WINDS WILL BACK OUT OF THE WEST-NORTHWEST WITH GUSTS UP TO
25 KTS WITH SCT-BKN DIURNAL CU DURING TODAY. IMPROVING TO VFR.
INTO THE EVENING AND ON INTO SUNDAY...WINDS SHOULD BECOME LIGHT
AND VARIABLE. SEA-BREEZE LIKELY TO IMPACT COASTAL TERMINALS. WILL
NEED TO MONITOR CLOSELY FOR THE DEVELOPMENT OF FOG OVERNIGHT IN
LOW LYING LOCATIONS AS MUCH COLDER AIR SETTLES INTO THE REGION.
MOSTLY CLEAR CONDITIONS. VFR.
KBOS TERMINAL...MODERATE CONFIDENCE.
WHILE FAIRLY CERTAIN ON TRENDS...THE TIMING OF IMPACTS OVER THE
NEXT SEVERAL HOURS COUPLED WITH IMPROVEMENT REMAINS CHALLENGING.
COULD SEE SEA-BREEZE IMPACTS ON SUNDAY.
KBDL TERMINAL...MODERATE CONFIDENCE.
GRADUAL IMPROVEMENT SHOULD BEGIN AS THE COLD FRONT HAS SWEPT
ACROSS THE TERMINAL...THE TIMING OF WHICH REMAINS TRICKY. COULD
SEE SOME FOG IMPACTS SATURDAY NIGHT INTO SUNDAY MORNING.
OUTLOOK...SUNDAY THROUGH WEDNESDAY...
SUNDAY NIGHT-MONDAY...VFR. LIGHT WINDS SUNDAY NIGHT. INCREASING
EAST WINDS MONDAY WITH GUSTS TO 25 KNOTS ALONG THE CAPE AND
ISLANDS/SOUTH COAST. HIGH CONFIDENCE.
MONDAY NIGHT-TUESDAY...CONDITIONS LOWERING LATER MONDAY NIGHT
WITH MVFR/IFR CIGS/VSBY POSSIBLE TUESDAY ESPECIALLY RI AND
SOUTHEAST MASS. MODERATE CONFIDENCE.
WEDNESDAY...CONDITIONS IMPROVING TO VFR DURING THE MORNING AND
AFTERNOON AS TUESDAY/S STORM MOVES OFF. A COLD FRONT APPROACHES
LATE IN THE DAY...BUT EFFECTS MAY HOLD OFF UNTIL WEDNESDAY NIGHT
WHEN CONDITIONS MAY LOWER TO MVFR/IFR IN SHOWERS/SCATTERED TSTMS.
LOW TO MODERATE CONFIDENCE.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...MODERATE CONFIDENCE THROUGH SUNDAY.
GALE WARNINGS WILL CONTINUE FOR A BRIEF PERIOD THIS MORNING...
REVERTING TO SMALL CRAFT ADVISORIES AS WINDS GRADUALLY RELAX BELOW
35 KTS.
THE EXPECTATION IS FOR WESTERLY FLOW BEHIND A COLD FRONT WHICH WILL
SWEEP ACROSS THE WATERS THIS MORNING INTO MIDDAY TO GUST UP TO 25
KTS AND KEEP SEAS IN EXCESS OF 5 FEET /UP TO 10 FEET ON THE OUTER
WATERS/. ANTICIPATE WIDESPREAD RAIN WITH EMBEDDED HEAVIER SHOWERS
RESULTING IN SOME MINOR VISIBILITY IMPACTS AHEAD OF THE COLD FRONT.
WINDS AND SEAS ARE ANTICIPATED TO FALL BELOW SMALL CRAFT ADVISORY
THRESHOLDS ON SUNDAY AS HIGH PRESSURE SETTLES ACROSS THE REGION.
OUTLOOK...SUNDAY THROUGH WEDNESDAY...
MODERATE CONFIDENCE SUNDAY TO TUESDAY. LOW TO MODERATE CONFIDENCE
WEDNESDAY.
SUNDAY...DIMINISHING WIND. LINGERING 5 FOOT SEAS EARLY ON THE OUTER
WATERS...SUBSIDING.
MONDAY...INCREASING EAST WIND WITH POTENTIAL SMALL CRAFT WIND GUSTS
TO 25 KNOTS AND SEAS 5 FEET OR HIGHER IN THE AFTERNOON AND AT NIGHT
ESPECIALLY ON THE SOUTHERN WATERS.
TUESDAY...SEAS AT OR ABOVE 5 FEET ON THE OPEN WATERS. EAST WINDS
GUSTING AROUND 25 KNOTS. SMALL CRAFT ADVISORY LIKELY. SHOWERS.
WEDNESDAY...A SHORT BREAK BETWEEN WEATHER SYSTEMS. WINDS GENERALLY
BELOW 25 KNOTS...BUT MAY INCREASE TO NEAR 25 KNOTS ON THE EASTERN
WATERS LATE IN THE DAY. SEAS 5-6 FEET MAINLY ON THE OUTER WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...GALE WARNING UNTIL 6 AM EDT EARLY THIS MORNING FOR ANZ231>234-
250-251.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR ANZ230-
236.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT SUNDAY FOR ANZ235-237.
GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR ANZ254-255.
SMALL CRAFT ADVISORY UNTIL 2 PM EDT SUNDAY FOR ANZ256.
&&
$$
SYNOPSIS...WTB/SIPPRELL
NEAR TERM...SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...WTB
AVIATION...WTB/BELK/SIPPRELL
MARINE...WTB/SIPPRELL
AREA FORECAST DISCUSSION
NWS TAUNTON MA
158 AM EDT SAT APR 20 2013
.SYNOPSIS...
WIDESPREAD RAIN WITH EMBEDDED HEAVIER SHOWERS AND THE POSSIBILITY
OF ISOLATED THUNDERSTORMS WILL CONTINUE INTO THE MORNING HOURS AS
A COLD FRONT GRADUALLY SWEEPS ACROSS THE AREA AND OFFSHORE. STRONG
SOUTHERLY WINDS WITH GUSTS UP TO 40 MPH CAN BE EXPECTED AHEAD OF
THE FRONT...BACKING OUT OF THE WEST IN WAKE WITH CONTINUED GUSTS
AROUND 25 MPH. COLDER AND DRIER AIR WILL ADVECT INTO THE REGION
FOR THE REMAINDER OF THE WEEKEND INTO THE EARLY PART OF NEXT WEEK.
A DEVELOPING COASTAL STORM WILL BRING SHOWERS AROUND TUESDAY...THEN
ANOTHER COLD FRONT MOVES THROUGH LATER IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
2 AM UPDATE...
IT HAS BEEN QUITE A BUSY NIGHT. CONTINUE TO MONITOR WIDESPREAD
RAIN WITH EMBEDDED HEAVIER SHOWERS. HAVE DIMINISHED THUNDERSTORM
POSSIBILITIES WITHIN THE FORECAST. LESSER CONFIDENCE. THERE ARE
STILL CONCERNS OF FASTER WINDS ALOFT BEING DRAGGED DOWN TO THE
SURFACE. THERE HAVE BEEN SEVERAL OBSERVATIONS ALREADY OF WINDS
GUSTING 40 TO 50 MPH. WILL BE CLOSELY MONITORING TOWARDS THE
ISSUANCE OF SPECIAL WEATHER STATEMENTS AND MARINE WARNINGS. GALE
WARNINGS CONTINUE ACROSS A MAJORITY OF THE WATERS.
MUCH OF THE RAIN AND ASSOCIATED GUSTY WINDS SHOULD BE ALONG THE
EAST SHORELINE AND OFFSHORE TOWARDS MORNING ALONG AND AHEAD OF THE
ATTENDANT COLD FRONT PRESENTLY /AS OF 2 AM/ ENTERING THE
CONNECTICUT RIVER VALLEY. NEAR-TERM MESOSCALE GUIDANCE HAS BEEN
DOING FAIRLY WELL IN HANDLING OUTCOMES...MOST ESPECIALLY A BLEND
OF THE WRF AND RAP FORECAST GUIDANCE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/...
SATURDAY INTO SATURDAY NIGHT...
COLD FRONT WILL EXIT THE REGION BY THE MID-MORNING HOURS. EXPECT
CONDITIONS TO LINGER ON ACK A LITTLE LONGER. OTHERWISE DRY AIR WILL
PUSH THROUGH BEHIND THE FRONT BRINGING IN SOME CAA. TEMPS TOMORROW
WILL BE ALMOST 10-15 DEGREES COOLER THEN TODAY WITH HIGHS IN THE
UPPER 50S TO LOW 60S. NW WINDS WILL INCREASE TOMORROW...GUSTING TO
20-25 MPH.
LOWS OVERNIGHT WILL DROP BACK BELOW THE FREEZING MARK EXCEPT FOR
AREAS ALONG THE COASTLINE. HIGH PRESSURE WILL SLOWLY TRY TO BUILD
ALLOWING FOR CLEARING SKIES AND LIGHT WINDS...PERFECT FOR
RADIATIONAL COOLING.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
BIG PICTURE...
UPPER RIDGE SHIFTS OVER THE WESTERN ATLANTIC. SECOND UPPER RIDGE
TAKES UP POSITION OFF THE PACIFIC COAST. THIS MAKES ROOM FOR A
BROAD TROUGH TO DIG OVER THE INTERIOR USA. SHORTWAVE IN THIS BROAD
FLOW MOVES FROM THE PACIFIC NORTHWEST TO THE SOUTHERN USA OVER THE
WEEKEND...THEN GENERATES A INVERTED TROUGH AT THE SURFACE OFF THE
CAROLINA COAST. THE FULL COMPLEX MOVES PAST NEW ENGLAND WEDNESDAY.
ANOTHER BETTER DEFINED SHORTWAVE DIVES SOUTH FROM NORTHERN CANADA
INTO THE INTERIOR USA TROUGH AND THEN SWINGS ACROSS NEW ENGLAND
LATE WEEK.
UPPER JET OVER NEW ENGLAND MOVES NORTHEAST PAST GREENLAND/ICELAND.
ANOTHER JET SEGMENT TRACES THE PACIFIC NORTHWEST/SOUTHERN
ROCKIES...THIS EVENTUALLY SWINGS NORTHEAST THROUGH THE GREAT LAKES
MIDWEEK AND THE NORTHEAST USA LATE WEEK.
MODEL PREFERENCES...
SMALL DIFFERENCE IN GFS AND ECMWF UPPER CONTOUR FIELDS REGARDING
COASTAL SYSTEM NEXT WEEK. OTHERWISE THE LONG RANGE MODELS ARE IN
GOOD AGREEMENT SURFACE AND ALOFT. WE USED A BLEND OF GFS/ECMWF
VALUES...AND BLEND WITH GMOS/HPC GRIDS WHERE AVAILABLE.
THE DAILIES...
SUNDAY-MONDAY...
HIGH PRESSURE BUILDS OVER THE REGION SUNDAY AND THEN MOVES
OFFSHORE MONDAY. GENERALLY FAIR WEATHER WITH INCREASING CIRRUS
DURING MONDAY. AS WIND FIELDS LIGHTEN SUNDAY AFTERNOON THERE WILL
BE THE POTENTIAL FOR A SEA BREEZE. THE OVERALL GRADIENT FLOW THEN
SUPPORTS AN EAST FLOW ON MONDAY. TEMPS IN THE MIXED LAYER WILL BE
-3C TO -5C SUNDAY WHICH WOULD SUPPORT 50S AT THE SURFACE. CLEAR
SKIES AND LIGHT WINDS WILL ALLOW RADIATIONAL COOLING SUNDAY
NIGHT...WITH DEWPOINTS IN THE 20S THAT SHOULD ALLOW FOR MIN TEMPS
IN THE 20S AND LOWER 30S EXCEPT A LITTLE MILDER ALONG THE COAST.
TEMPS ALOFT WARM A LITTLE ON MONDAY...BUT THE BUFFERING OF THE
INCREASED EAST FLOW SHOULD BALANCE OFF ANY WARMING.
MONDAY NIGHT-TUESDAY...
INVERTED TROUGH/DEVELOPING COASTAL LOW WILL START PUSHING DEEPER
MOISTURE UP THE COAST. ALL MODEL PCPN FORECASTS ARE WELL SOUTH OF
NEW ENGLAND MONDAY EVENING BUT MOVE MEASURABLE PCPN INTO THE
AREA...ESPECIALLY THE SOUTH COAST...AFTER 06Z/2AM. WE SLOWED THE
HOURLY POP VALUES A FEW HOURS BASED ON THIS MODEL AGREEMENT. NEW
ENGLAND IS IN THE RIGHT ENTRANCE REGION OF THE DEPARTING UPPER JET
THROUGH TUESDAY SO DEVELOPMENT AND PCPN ARE REASONABLE. CHANCE
POPS UNTIL THE SURFACE LOW/UPPER SHORTWAVE MOVE PAST ON TUESDAY
NIGHT.
WEDNESDAY-THURSDAY...
PLAINS/GREAT LAKES TROUGH AND SUPPORTING UPPER JET MOVE UP THE ST
LAWRENCE VALLEY INTO CANADA. THIS FEATURE WILL SUPPORT A COLD
FRONT THAT WILL SWING THROUGH NEW ENGLAND WEDNESDAY NIGHT-
THURSDAY. ON WEDNESDAY POPS SHOW A BREAK AFTER THE COASTAL SYSTEM
MOVES OFF...BUT THEN A RESUMPTION OF CHANCE POPS AS THE GREAT
LAKES COLD FRONT MOVES THROUGH. THE DEPICTION OF TWO DISTINCT
SYSTEMS IS REASONABLE GIVEN THAT ONE IS SOUTHERN STREAM AND THE
OTHER IS NORTHERN STREAM...BUT THE DISTINCTNESS/LENGTH OF TIME
BETWEEN THE TWO PCPN SHIELDS IS LESS CERTAIN.
FRIDAY...
HIGH PRESSURE BUILDS AT THE SURFACE WHILE THE SUPPORTING UPPER
TROUGH FROM THURSDAY/S FRONT WILL STILL BE IN THE NEIGHBORHOOD. NO
DESTABILIZING EXPECTED AS UPPER TEMPS SHOW LITTLE CHANGE AND
MOISTURE IS LIMITED. EXPECT A DRY DAY WITH SIMILAR MAX/MIN TEMPS.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...
* MODERATE CONFIDENCE INTO SATURDAY MORNING...
* HIGH CONFIDENCE SATURDAY AFTERNOON INTO SUNDAY...
A MIX OF MVFR-IFR CIGS AND VSBYS CONTINUE WITH THE BROAD AREA OF
RAIN WITH EMBEDDED HEAVIER SHOWERS. ALREADY BEGINNING TO SEE WINDS
BACKING OUT OF THE WEST-NORTHWEST WITH THE COLD FRONTAL PASSAGE
INTO THE CONNECTICUT RIVER VALLEY...THOUGH CIGS ARE SLOW TO LIFT.
WHILE DIFFICULTIES PERSIST IN TIMING OF IMPROVEMENT WEST TO
EAST...HAVE CONFIDENCE CONCERNING THE OVERALL TREND THAT VSBYS
WILL QUICKLY IMPROVE BEHIND THE COLD FRONT AND CIGS WILL GRADUALLY
LIFT. WINDS WILL BACK OUT OF THE WEST-NORTHWEST WITH GUSTS UP TO
25 KTS WITH SCT-BKN DIURNAL CU DURING TODAY. IMPROVING TO VFR.
INTO THE EVENING AND ON INTO SUNDAY...WINDS SHOULD BECOME LIGHT
AND VARIABLE. SEA-BREEZE LIKELY TO IMPACT COASTAL TERMINALS. WILL
NEED TO MONITOR CLOSELY FOR THE DEVELOPMENT OF FOG OVERNIGHT IN
LOW LYING LOCATIONS AS MUCH COLDER AIR SETTLES INTO THE REGION.
MOSTLY CLEAR CONDITIONS. VFR.
KBOS TERMINAL...MODERATE CONFIDENCE.
WHILE FAIRLY CERTAIN ON TRENDS...THE TIMING OF IMPACTS OVER THE
NEXT SEVERAL HOURS COUPLED WITH IMPROVEMENT REMAINS CHALLENGING.
COULD SEE SEA-BREEZE IMPACTS ON SUNDAY.
KBDL TERMINAL...MODERATE CONFIDENCE.
GRADUAL IMPROVEMENT SHOULD BEGIN AS THE COLD FRONT HAS SWEPT
ACROSS THE TERMINAL...THE TIMING OF WHICH REMAINS TRICKY. COULD
SEE SOME FOG IMPACTS SATURDAY NIGHT INTO SUNDAY MORNING.
OUTLOOK...SUNDAY THROUGH WEDNESDAY...
SUNDAY NIGHT-MONDAY...VFR. LIGHT WINDS SUNDAY NIGHT. INCREASING
EAST WINDS MONDAY WITH GUSTS TO 25 KNOTS ALONG THE CAPE AND
ISLANDS/SOUTH COAST. HIGH CONFIDENCE.
MONDAY NIGHT-TUESDAY...CONDITIONS LOWERING LATER MONDAY NIGHT
WITH MVFR/IFR CIGS/VSBY POSSIBLE TUESDAY ESPECIALLY RI AND
SOUTHEAST MASS. MODERATE CONFIDENCE.
WEDNESDAY...CONDITIONS IMPROVING TO VFR DURING THE MORNING AND
AFTERNOON AS TUESDAY/S STORM MOVES OFF. A COLD FRONT APPROACHES
LATE IN THE DAY...BUT EFFECTS MAY HOLD OFF UNTIL WEDNESDAY NIGHT
WHEN CONDITIONS MAY LOWER TO MVFR/IFR IN SHOWERS/SCATTERED TSTMS.
LOW TO MODERATE CONFIDENCE.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...MODERATE CONFIDENCE THROUGH SUNDAY.
QUICK UPDATE TO NARRANGANSETT BAY...NOW UNDER A GALE WARNING.
WIND GUSTS HAVE BEEN APPROACHING GALE FORCE ALREADY AND
EXPECTATIONS ARE FOR SEVERAL MORE HOURS OF GUSTS THIS STRONG OR
EVEN STRONGER AS CONVECTION APPROACHES.
STRONG SOUTHERLY WINDS WITH GUSTS TO 25KTS. AS A STRONG COLD
FRONT APPROACHES GUSTS WILL INCREASE TO STRONG SCA TO MARGINAL
GALES. DECIDED TO HOIST THE GALE WARNING UP DUE TO COLD FRONT
PASSAGE ALLOWING FOR STRONGER WINDS ALOFT TO MIX DOWN. THESE GALES
MAY REACH TO 40KTS. SHOWERS AND THUNDERSTORMS EXPECTED OVERNIGHT
INTO EARLY SAT MORNING WILL LIKELY RESULT IN SOME TEMPORARY
VISIBILITY RESTRICTIONS.
BEHIND THE COLD FRONT...WINDS WILL BACK OUT OF THE WEST-NORTHWEST
CONTINUALLY GUSTING IN EXCESS OF 25 KTS. SMALL CRAFT ADVISORIES
WILL NEED TO BE ISSUED ACCORDINGLY. AS SEAS WILL STILL REMAIN
CHOPPY AND GREATER THAN 5 FEET. HIGH PRESSURE WILL BUILD SATURDAY
NIGHT ALLOWING FOR CALM WINDS AND SEAS TO SLOWLY RELAX.
OUTLOOK...SUNDAY THROUGH WEDNESDAY...
MODERATE CONFIDENCE SUNDAY TO TUESDAY. LOW TO MODERATE CONFIDENCE
WEDNESDAY.
SUNDAY...DIMINISHING WIND. LINGERING 5 FOOT SEAS EARLY ON THE OUTER
WATERS...SUBSIDING.
MONDAY...INCREASING EAST WIND WITH POTENTIAL SMALL CRAFT WIND GUSTS
TO 25 KNOTS AND SEAS 5 FEET OR HIGHER IN THE AFTERNOON AND AT NIGHT
ESPECIALLY ON THE SOUTHERN WATERS.
TUESDAY...SEAS AT OR ABOVE 5 FEET ON THE OPEN WATERS. EAST WINDS
GUSTING AROUND 25 KNOTS. SMALL CRAFT ADVISORY LIKELY. SHOWERS.
WEDNESDAY...A SHORT BREAK BETWEEN WEATHER SYSTEMS. WINDS GENERALLY
BELOW 25 KNOTS...BUT MAY INCREASE TO NEAR 25 KNOTS ON THE EASTERN
WATERS LATE IN THE DAY. SEAS 5-6 FEET MAINLY ON THE OUTER WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...GALE WARNING UNTIL 6 AM EDT EARLY THIS MORNING FOR ANZ231>234-
250-251-256.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR ANZ230.
GALE WARNING UNTIL 3 AM EDT EARLY THIS MORNING FOR ANZ235>237.
GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR ANZ254-255.
&&
$$
SYNOPSIS...WTB/DUNTEN
NEAR TERM...SIPPRELL
SHORT TERM...DUNTEN
LONG TERM...WTB
AVIATION...WTB/BELK/SIPPRELL
MARINE...WTB/DUNTEN
AREA FORECAST DISCUSSION
NWS MIAMI FL
217 PM EDT SAT APR 20 2013
.DISCUSSION...
SATURDAY THROUGH MONDAY...
IN THE SHORT TERM FOR THIS AFTERNOON AND EVENING THERE IS NOT MUCH
CHANGE FROM THE PREVIOUS THINKING. THE SHOWERS AND THUNDERSTORMS
OVER THE ATLANTIC WATERS HAVE DIMINISHED IN COVERAGE BUT A FEW
SHOWERS ARE BEGINNING TO DEVELOP ALONG THE SEA BREEZE EXTENDING FROM
SOUTH MIAMI-DADE TO COASTAL PALM BEACH COUNTY AS WELL AS WEST OF
LAKE OKEECHOBEE ASSOCIATED WITH THE FRONT ITSELF. THIS PATTERN IS
CONSISTENT WITH THE FORECAST OF HIGH RESOLUTION MODELS FOR THIS
AFTERNOON AND EVENING. FAVORING FACTORS FOR THE FORMATION OF SHOWERS
AND THUNDERSTORMS ALONG THE EAST COAST ARE: THE WEAK SOUTHWESTERLY
FLOW AND THE TROUGH OF LOW PRESSURE NEAR THE FLORIDA EAST COAST. THE
LIMITING FACTORS ARE THE WARM 500 MB TEMPERATURES AND THE CAP AROUND
15KFT. IT IS POSSIBLE THAT ONCE THE ACTIVITY ALONG THE SEA BREEZE
REACHES THE CAP IT COULD DIMINISH IN INTENSITY BUT STILL PRODUCE
HEAVY RAINS, GUSTY WINDS, AND LIGHTNING. IN OTHER WORDS, IT COULD
START ACTIVE IN THE NEXT FEW HOURS AND THEN WEAKEN A BIT AS THE
STORMS START REACHING THE CAP. THE ADVANCE OF THE FRONT IS ALSO A
FAVORABLE FACTOR THAT IT COULD BECOME MORE IMPORTANT AS THE DAY
PROGRESSES. THE STEERING FLOW WILL MOVE STORMS GENERALLY FROM WEST
TO EAST. THIS WILL INCREASE THE POTENTIAL FOR THUNDERSTORMS FOR
THE EAST COAST.
THE CURRENT 500 MB PATTERN SHOWS A TROUGH OF LOW PRESSURE OVER THE
EASTERN AND CENTRAL US AND A STRONG BLOCKING RIDGE OF HIGH PRESSURE
OVER THE WESTERN ATLANTIC. AS THE HIGH CONTINUES TO MOVE FURTHER
EAST COOLER 500 MB TEMPERATURES WILL SPREAD OVER SOUTH FLORIDA ON
SUNDAY. THIS IS EXPECTED TO INCREASE THE POTENTIAL FOR STRONG OR
EVEN SEVERE STORMS ON SUNDAY IF HEATING IS FAVORABLE.
LONG TERM /TUESDAY THROUGH FRIDAY/...
BEHIND THE SURFACE TROUGH...A MORE TYPICAL SPRING WEATHER REGIME
WILL TAKE HOLD OVER FLORIDA...WITH EASTERLY LOW-LEVEL FLOW AND
HIGH PRESSURE BUILDING BOTH NEAR SURFACE AND ALOFT. ISOLATED
MAINLY DIURNAL SHOWERS ARE EXPECTED...WITH PARTLY TO MOSTLY SUNNY
SKIES AND TEMPERATURES REMAINING SLIGHTLY ABOVE AVERAGE.
&&
.AVIATION...ISSUED AT 147 PM EDT SAT APR 20 2013...
SHOWERS AND THUNDERSTORMS ARE BEGINNING TO SAG INTO THE NORTHWEST
INTERIOR AREAS. WITH AN ESTABLISHED GULF COAST SEA BREEZE...THIS
ACTIVITY SHOULD CONTINUE TO PUSH TO THE EAST. ADDITIONAL
CONVECTION WILL ALSO BE POSSIBLE ACROSS THE EAST COAST TERMINALS
OVER THE NEXT FEW HOURS OF PEAK HEATING. KEPT TEMPO GROUPS AT ALL
EAST COAST SITES FROM 20Z-23Z. WILL AMEND IF NECESSARY.
&&
MARINE...
LONG-FUSED ADVISORIES AND WARNINGS ARE NOT EXPECTED THIS WEEKEND
OR NEXT WEEK OVER THE WATERS. LOCALLY HIGH WAVES AND WINDS CAN BE
EXPECTED IN SCATTERED TO NUMEROUS THUNDERSTORMS TODAY THROUGH
MONDAY...AND SPECIAL MARINE WARNINGS MAY BE ISSUED FROM TIME TO
TIME.
&&
FIRE WEATHER...
MINIMUM RELATIVE HUMIDITY VALUES WILL BE ABOVE 50 PERCENT THIS
WEEKEND AND EARLY NEXT WEEK...AS MOIST ATMOSPHERE CONTRIBUTES TO
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. WINDS WILL MAINLY
SOUTH TODAY...BUT TRANSITION TO THE NORTHEAST TONIGHT AS COLD FRONT
MOVES IN. LOW WIND SPEEDS ARE EXPECTED OUTSIDE OF SHOWERS AND
THUNDERSTORMS.
&&
.PREV DISCUSSION... /ISSUED 947 AM EDT SAT APR 20 2013/
UPDATE...
SHOWERS AND THUNDERSTORMS OVER THE ATLANTIC WATERS HAVE DEVELOPED
THIS MORNING DUE TO THE CONVERGENCE OF SE FLOW OVER THE BAHAMAS
AND MORE SOUTHERLY FLOW OVER SOUTH FLORIDA. THE 12Z SOUNDING FROM
THIS MORNING SHOWS A CAP AROUND 650 MB ASSOCIATED WITH THE
SUBTROPICAL HIGH PRESSURE OVER THE ATLANTIC AND THE GULF. 500 MB
TEMPERATURES ARE AROUND -6C AND ARE NOT EXPECTED TO COOL BEYOND
-7C THIS AFTERNOON. HOWEVER, THE INFLUENCE OF A COLD FRONT MOVING
SOUTHWARD IS EXPECTED TO INTERACT WITH A WEAK EAST COAST SEA
BREEZE TO TRIGGER SHOWERS AND THUNDERSTORMS, ESPECIALLY IN PALM
BEACH AND BROWARD COUNTIES. SOME STORMS CAN ALSO EXTEND INTO
MIAMI-DADE. FOR THE WEST COAST THERE IS ONLY A SMALL CHANCE OF
THUNDERSTORMS, SINCE MOST OF THE SURFACE TROUGH IS ALIGNED FROM
NORTHEAST TO SOUTHWEST OVER THE ATLANTIC WATERS.
AS MENTIONED IN THE PREVIOUS DISCUSSION THE UPPER LEVEL
TEMPERATURES ARE FORECAST TO COOL ON SUNDAY ALLOWING FOR A GREATER
CHANCE OF THUNDERSTORMS THAN TODAY.
FOR TODAY THE HIGHEST POPS ARE STILL INCLUDED FOR PALM BEACH AND
BROWARD.
PREV DISCUSSION... /ISSUED 725 AM EDT SAT APR 20 2013/
AVIATION...
MOSTLY VFR CONDITIONS WILL OCCUR EARLY IN THE FORECAST ALTHOUGH
THERE COULD BE A BRIEF MVFR CIG AS A FEW SHOWERS MOVE ACROSS SOUTH
FLORIDA. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP BY THIS AFTERNOON AHEAD OF A WEAKENING COLD
FRONT THAT WILL SAG ACROSS THE REGION. THE HRRR INDICATES
CONVECTION TO BEGIN DEVELOPING IN EARNEST BETWEEN 18-20Z WITH THE
STEERING FLOW TAKING THE STORMS TO THE EAST COAST. THEREFORE, HAVE
LEFT TEMPO 18-22Z FOR ALL EAST TERMINALS WITH SOME OF THE ACTIVITY
POSSIBLY PERSISTING BEYOND THIS TIME FRAME. SURFACE WINDS ARE
QUESTIONABLE WITH A SLOW MOVING FRONTAL BOUNDARY BUT GENERALLY
SSW-SSE AHEAD OF THE FRONT AND NE BEHIND THE FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 73 84 70 83 / 40 60 40 60
FORT LAUDERDALE 74 85 72 84 / 30 60 40 60
MIAMI 75 86 73 85 / 30 50 40 60
NAPLES 69 86 70 84 / 20 40 40 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...71/JE
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS MIAMI FL
147 PM EDT SAT APR 20 2013
.AVIATION...
SHOWERS AND THUNDERSTORMS ARE BEGINNING TO SAG INTO THE NORTHWEST
INTERIOR AREAS. WITH AN ESTABLISHED GULF COAST SEA BREEZE...THIS
ACTIVITY SHOULD CONTINUE TO PUSH TO THE EAST. ADDITIONAL
CONVECTION WILL ALSO BE POSSIBLE ACROSS THE EAST COAST TERMINALS
OVER THE NEXT FEW HOURS OF PEAK HEATING. KEPT TEMPO GROUPS AT ALL
EAST COAST SITES FROM 20Z-23Z. WILL AMEND IF NECESSARY.
&&
.PREV DISCUSSION... /ISSUED 947 AM EDT SAT APR 20 2013/
UPDATE...
SHOWERS AND THUNDERSTORMS OVER THE ATLANTIC WATERS HAVE DEVELOPED
THIS MORNING DUE TO THE CONVERGENCE OF SE FLOW OVER THE BAHAMAS
AND MORE SOUTHERLY FLOW OVER SOUTH FLORIDA. THE 12Z SOUNDING FROM
THIS MORNING SHOWS A CAP AROUND 650 MB ASSOCIATED WITH THE
SUBTROPICAL HIGH PRESSURE OVER THE ATLANTIC AND THE GULF. 500 MB
TEMPERATURES ARE AROUND -6C AND ARE NOT EXPECTED TO COOL BEYOND
-7C THIS AFTERNOON. HOWEVER, THE INFLUENCE OF A COLD FRONT MOVING
SOUTHWARD IS EXPECTED TO INTERACT WITH A WEAK EAST COAST SEA
BREEZE TO TRIGGER SHOWERS AND THUNDERSTORMS, ESPECIALLY IN PALM
BEACH AND BROWARD COUNTIES. SOME STORMS CAN ALSO EXTEND INTO
MIAMI-DADE. FOR THE WEST COAST THERE IS ONLY A SMALL CHANCE OF
THUNDERSTORMS, SINCE MOST OF THE SURFACE TROUGH IS ALIGNED FROM
NORTHEAST TO SOUTHWEST OVER THE ATLANTIC WATERS.
AS MENTIONED IN THE PREVIOUS DISCUSSION THE UPPER LEVEL
TEMPERATURES ARE FORECAST TO COOL ON SUNDAY ALLOWING FOR A GREATER
CHANCE OF THUNDERSTORMS THAN TODAY.
FOR TODAY THE HIGHEST POPS ARE STILL INCLUDED FOR PALM BEACH AND
BROWARD.
PREV DISCUSSION... /ISSUED 725 AM EDT SAT APR 20 2013/
AVIATION...
MOSTLY VFR CONDITIONS WILL OCCUR EARLY IN THE FORECAST ALTHOUGH
THERE COULD BE A BRIEF MVFR CIG AS A FEW SHOWERS MOVE ACROSS SOUTH
FLORIDA. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP BY THIS AFTERNOON AHEAD OF A WEAKENING COLD
FRONT THAT WILL SAG ACROSS THE REGION. THE HRRR INDICATES
CONVECTION TO BEGIN DEVELOPING IN EARNEST BETWEEN 18-20Z WITH THE
STEERING FLOW TAKING THE STORMS TO THE EAST COAST. THEREFORE, HAVE
LEFT TEMPO 18-22Z FOR ALL EAST TERMINALS WITH SOME OF THE ACTIVITY
POSSIBLY PERSISTING BEYOND THIS TIME FRAME. SURFACE WINDS ARE
QUESTIONABLE WITH A SLOW MOVING FRONTAL BOUNDARY BUT GENERALLY
SSW-SSE AHEAD OF THE FRONT AND NE BEHIND THE FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 71 83 72 84 / 40 60 40 60
FORT LAUDERDALE 75 84 74 85 / 30 60 40 60
MIAMI 73 85 73 85 / 30 50 40 60
NAPLES 69 86 69 87 / 20 40 40 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...71/JE
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS MIAMI FL
947 AM EDT SAT APR 20 2013
.UPDATE...
SHOWERS AND THUNDERSTORMS OVER THE ATLANTIC WATERS HAVE DEVELOPED
THIS MORNING DUE TO THE CONVERGENCE OF SE FLOW OVER THE BAHAMAS
AND MORE SOUTHERLY FLOW OVER SOUTH FLORIDA. THE 12Z SOUNDING FROM
THIS MORNING SHOWS A CAP AROUND 650 MB ASSOCIATED WITH THE
SUBTROPICAL HIGH PRESSURE OVER THE ATLANTIC AND THE GULF. 500 MB
TEMPERATURES ARE AROUND -6C AND ARE NOT EXPECTED TO COOL BEYOND
-7C THIS AFTERNOON. HOWEVER, THE INFLUENCE OF A COLD FRONT MOVING
SOUTHWARD IS EXPECTED TO INTERACT WITH A WEAK EAST COAST SEA
BREEZE TO TRIGGER SHOWERS AND THUNDERSTORMS, ESPECIALLY IN PALM
BEACH AND BROWARD COUNTIES. SOME STORMS CAN ALSO EXTEND INTO
MIAMI-DADE. FOR THE WEST COAST THERE IS ONLY A SMALL CHANCE OF
THUNDERSTORMS, SINCE MOST OF THE SURFACE TROUGH IS ALIGNED FROM
NORTHEAST TO SOUTHWEST OVER THE ATLANTIC WATERS.
AS MENTIONED IN THE PREVIOUS DISCUSSION THE UPPER LEVEL
TEMPERATURES ARE FORECAST TO COOL ON SUNDAY ALLOWING FOR A GREATER
CHANCE OF THUNDERSTORMS THAN TODAY.
FOR TODAY THE HIGHEST POPS ARE STILL INCLUDED FOR PALM BEACH AND
BROWARD.
&&
.PREV DISCUSSION... /ISSUED 725 AM EDT SAT APR 20 2013/
AVIATION...
MOSTLY VFR CONDITIONS WILL OCCUR EARLY IN THE FORECAST ALTHOUGH
THERE COULD BE A BRIEF MVFR CIG AS A FEW SHOWERS MOVE ACROSS SOUTH
FLORIDA. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP BY THIS AFTERNOON AHEAD OF A WEAKENING COLD
FRONT THAT WILL SAG ACROSS THE REGION. THE HRRR INDICATES
CONVECTION TO BEGIN DEVELOPING IN EARNEST BETWEEN 18-20Z WITH THE
STEERING FLOW TAKING THE STORMS TO THE EAST COAST. THEREFORE, HAVE
LEFT TEMPO 18-22Z FOR ALL EAST TERMINALS WITH SOME OF THE ACTIVITY
POSSIBLY PERSISTING BEYOND THIS TIME FRAME. SURFACE WINDS ARE
QUESTIONABLE WITH A SLOW MOVING FRONTAL BOUNDARY BUT GENERALLY
SSW-SSE AHEAD OF THE FRONT AND NE BEHIND THE FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 85 71 83 72 / 60 40 60 40
FORT LAUDERDALE 85 75 84 74 / 50 30 60 40
MIAMI 87 73 85 73 / 40 30 50 40
NAPLES 86 69 86 69 / 40 20 40 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...71/JE
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS MIAMI FL
725 AM EDT SAT APR 20 2013
.AVIATION...
MOSTLY VFR CONDITIONS WILL OCCUR EARLY IN THE FORECAST ALTHOUGH
THERE COULD BE A BRIEF MVFR CIG AS A FEW SHOWERS MOVE ACROSS SOUTH
FLORIDA. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP BY THIS AFTERNOON AHEAD OF A WEAKENING COLD
FRONT THAT WILL SAG ACROSS THE REGION. THE HRRR INDICATES
CONVECTION TO BEGIN DEVELOPING IN EARNEST BETWEEN 18-20Z WITH THE
STEERING FLOW TAKING THE STORMS TO THE EAST COAST. THEREFORE, HAVE
LEFT TEMPO 18-22Z FOR ALL EAST TERMINALS WITH SOME OF THE ACTIVITY
POSSIBLY PERSISTING BEYOND THIS TIME FRAME. SURFACE WINDS ARE
QUESTIONABLE WITH A SLOW MOVING FRONTAL BOUNDARY BUT GENERALLY
SSW-SSE AHEAD OF THE FRONT AND NE BEHIND THE FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 85 71 83 72 / 60 40 60 40
FORT LAUDERDALE 85 75 84 74 / 50 30 60 40
MIAMI 87 73 85 73 / 40 30 50 40
NAPLES 86 69 86 69 / 40 20 40 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MELBOURNE FL
427 AM EDT SAT APR 20 2013
.DISCUSSION...
TODAY...
A THIN BAND OF SHOWERS ACCOMPANYING A COLD FRONT...STRETCHING FROM
DAYTONA BEACH TO TAMPA...WILL SLOWLY CROSS EC FL AND SETTLE OVER
SOUTH FLORIDA BY EVE. SOME HEATING SHOULD OCCUR SOUTH OF ORLANDO
PRIOR TO FRONTAL PASSAGE THIS MORNING AND EARLY AFTERNOON WHICH
SHOULD PRODUCE A BETTER CHANCE FOR DEEP CONVECTION (THUNDER). WILL
HOLD ONTO SCATTERED SHOWERS ACROSS THE NORTH EVEN AFTER THE BAND
MOVES THROUGH AS A MID LEVEL DISTURBANCE CROSSES NORTH FLORIDA LATER
TODAY AND THIS EVENING. MOS GUIDANCE POPS LOOK TOO HIGH THOUGH AND
HAVE DRAWN 50 POPS MOST AREAS. IN FACT...THINK COVERAGE SHOULD BE A
LITTLE HIGHER ACROSS THE SOUTHERN 1/3 OF FA...WITH 60 POPS.
TEMPERATURES ARE TRICKY TODAY ESP ACROSS THE NORTH. IN SOME PLACES
THE HIGH MAY OCCUR EARLY THIS MORNING JUST BEFORE FRONTAL PASSAGE.
NORTH WINDS 15 MPH AND WIDESPREAD LOW CLOUDS BEHIND THE FRONT WILL
LIMIT SFC HEATING. FOR EXAMPLE...DAYTONA BEACH WILL LIKELY FALL
INTO THE 60S BEHIND THE FRONT AND NOT CLIMB BACK OUT. ON THE OTHER
HAND...MAX TEMPS SHOULD REACH THE MID 80S AROUND LAKE OKEECHOBEE/
MARTIN COUNTY.
TONIGHT...
FRONT IS FORECAST TO HANG UP JUST TO OUR SOUTH BUT CONSIDERABLE
MOISTURE WILL REMAIN OVER THE AREA. THERE MAY BE SOME RESIDUAL
SHOWERS ACROSS THE NORTH ASSOCD WITH DEPARTING MID LEVEL SHORTWAVE
AND UPPER JET. SO WILL HOLD ONTO 30 POPS FOR SHOWERS IN LAKE AND
VOLUSIA IN THE EVENING. PERSISTENT ONSHORE FLOW WILL REQUIRE A 20
POP ALONG THE COAST MAINLY FOR POTENTIAL FOR A FEW BANDS TO SET UP
AND CROSS THE COAST.
SUN-MON...
UNSEASONABLE WET WX PATTERN FOR CENTRAL FL...GIVEN THAT APR IS
CLIMATOLOGICALLY THE DRIEST MONTH OF THE YEAR. A COLD FRONT
EXTENDING FROM THE MID ATLC TO THE YUCATAN PENINSULA WILL GRIND TO A
HALT AGAINST A LARGE HI PRES RIDGE OVER THE WRN ATLC. DEEP MOISTURE
POOLING WITHIN THE FRONTAL TROF WILL MERGE WITH RELATIVELY HIGH
MOISTURE OVER THE WRN ATLC/NW CARIB...ALLOWING PWAT VALUES TO REACH
AS HIGH AS 1.5"-1.7" ALONG THE TREASURE COAST. LOWER PWATS
(1.3"-1.5") ALONG AND N OF THE I-4 CORRIDOR AS POST FRONTAL DRY AIR
WORKS ITS WAY DOWN THE PENINSULA.
H30-H20 LIFTING JET OVER THE ERN CONUS/NRN GOMEX WILL GENERATE
STRONG UPR LVL DIVERGENCE ACRS THE REGION. UPSTREAM MID LVL ENERGY
IS RATHER SPARSE AS THE LATEST RUC ANALYSIS SHOWS LITTLE IN THE WAY
OF ORGANIZED H85-H50 VORTICITY OVER THE SRN TIER STATES. OMEGA LIFT
ALONG THE FRONTAL BOUNDARY...HOWEVER...SHOULD PROVIDE SUFFICIENT MID
LVL SUPPORT TO KEEP POPS AOA 50PCT. WILL GO WITH 50 POPS ALONG AND N
OF I-4...60 POPS TO THE S DUE TO DEEPER AND MORE ABUNDANT MOISTURE.
WILL KEEP THUNDER IN THE SLGT CHC CATEGORY TUE TO THE LACK OF
LOW/MID LVL INSTABILITY.
NE BREEZE WILL PREVAIL...ALLOWING OCEAN MODIFIED AIR TO ADVECT ACRS
THE CENTRAL PENINSULA. MAX TEMPS IN THE U70S/L80S ALONG THE COAST...
L/M80S INTERIOR. MIN TEMPS M/U60S ALONG THE COAST...L/M60S INTERIOR.
TUE-FRI...
PRECIP TO LINGER INTO TUE AS MOISTURE CONTINUES TO POOL WITHIN THE
WEAKENING FRONTAL BOUNDARY. GFS/ECMWF MODELS IN GOOD AGREEMENT WITH
THE DVLPMNT OF A WEAK SPOT LOW OFF THE CAROLINA COAST BY DAYBREAK
TUE. THE NEWLY DVLPD LOW WILL PROVIDE THE TORQUE NECESSARY TO CRANK
THE FRONTAL REMNANTS INTO S FL WHILE HELPING DRIER CONTINENTAL AIR
TO FILTER INTO CENTRAL FL.
MODELS HAVE BACKED OFF THEIR PREVIOUS SOLUTION OF BRINGING A NEW
COLD FRONT INTO CENTRAL FL LATE WED INTO THU. GFS STALLS IT OVER THE
PANHANDLE WHILE ECMWF INDICATES ITS SRN EXTENSION WILL DISSIPATE AS
IT PUSHES DOWN THE PENINSULA. INCLINED TO GO WITH THE DRIER SOLUTION
GIVEN THIS TIME OF YEAR IS THE PEAK OF THE DRY SEASON. WILL KEEP
SMALL POPS IN THE FCST FOR THU TO ACCOUNT FOR THE PRESENCE OF THE
FRONT...POPS TOO LOW TO MENTION THRU THE REMAINDER OF THE FCST.
NO INDICATIONS OF UNUSUALLY HIGH OR LOW TEMPS THRU THE UPCOMING
WEEK...READINGS SHOULD BE WITHIN ABOUT 5F DEG OF CLIMO AVGS.
&&
.AVIATION...
FRONT WILL PRESS E/SE AND CROSS LEE/DAB/SFB/MCO BY 8 AM...FPR/SUA
BY 18Z. THIN BAND OF SHRA WILL ACCOMPANY THE FRONT WITH SCATTERED
SHRA/ISOLATED TSRA POSSIBLE AHEAD OF THE FRONT WHERE SFC HEATING
CAN OCCUR SOUTH OF MCO. PRIMARY IMPACT WILL BE PREVAILING MVFR
CIGS BEHIND THE FRONT WITH TEMPO IFR CIGS POSS ESP THROUGH 13Z MCO
NORTHWARD. THERE SHOULD BE A PERIOD OF VFR CIGS DURING THE AFTN
AND EARLY EVE ACROSS MANY TERMINALS BUT EXPECT PREVAILING MVFR
CIGS TO RETURN AFT 00Z.
&&
.MARINE...
TODAY...AS EXPECTED THE SOUTHERLY FLOW HAS WEAKENED A BIT AS PRES
GRAD BECOMES BAGGY ASSOCD WITH FRONTAL ZONE. BUT A SURGE OF NORTH
WINDS WILL OVERSPREAD THE NORTHERN WATERS EARLY THIS MORNING
BEHIND THE FRONT SO HAVE RAISED SMALL CRAFT ADVISORY FOR THE
OFFSHORE VOLUSIA WATERS FOR 20 KNOTS. CLOSER TO THE COAST AND TO
THE SOUTH EXPECT 15-20 KNOTS SO WILL HEADLINE CAUTION. BUT
CONDITIONS WILL BE QUITE UNFAVORABLE ESPECIALLY IN THE GULF
STREAM. IN ADDITION...A BAND OF SHOWERS WILL PUSH OFFSHORE ASSOCD
WITH THE FRONT WITH A FEW STORMS PUSHING OFFSHORE BREVARD TO THE
TREASURE COAST.
TONIGHT...WEAK FRONTAL TROUGH IS FORECAST TO STALL JUST TO THE
SOUTH AND EAST OF THE OUR COASTAL WATERS. THE NORTH TO NORTHEAST
PRES GRAD WILL SUPPORT 15 KNOTS SO WILL LIKELY NEED A CAUTION IN
THE GULF STREAM WITH SEAS UP TO 6 FT.
SUN-SUN NIGHT...A STRONG HIGH PRES RIDGE WILL BUILD ACRS THE ERN
CONUS...GENERATING A MODERATE TO FRESH NE BREEZE. WINDS BCMG A LIGHT
TO GENTLE SE BREEZE S OF SEBASTIAN INLET AFT SUNSET AS AN INVERTED
TROF BEGINS TO FORM OVER S FL ALONG A STALLED FRONTAL BNDRY.
SCT/NMRS SHRAS AND ISOLD TSRAS. SEAS BUILDING TO 6-8FT N OF
SEBASTIAN INLET...4-6FT TO THE SOUTH.
MON-MON NIGHT...THE HIGH PRES RIDGE WILL LIFT INTO THE CANADIAN
MARITIMES...TRAILING ITS RIDGE AXIS DOWN THE ERN CONUS AND INTO THE
LWR MS VALLEY. A WEAK LOW WILL DVLP OFF THE CAROLINA COAST AND
INTERACT WITH THE RIDGE...GENERATING A MODERATE TO FRESH NE BREEZE N
OF SEBASTIAN INLET. S OF THE INLET PGRAD WILL BE WEAKER DUE TO THE
FURTHER PROXIMITY TO THE DLVPG LOW...GENTLE TO MODERATE E/NE BREEZE
WILL RESULT. SEAS 6-8FT N OF SEBASTIAN INLET...4-6FT TO THE SOUTH.
TUE-TUE NIGHT...WINDS WILL DIMINISH AS THE LOW LIFTS UP THE ERN
SEABOARD...BCMG A GENTLE TO MODERATE NE BREEZE AREAWIDE BY LATE
AFTN. PERSISTENT E/NERLY FETCH OVER THE WRN ATLC WILL PUSH A SWELL
INTO THE E FL COAST...KEEPING SEAS 4-6FT NEARSHORE AND 5-7FT
OFFSHORE.
WED-WED NIGHT...A HIGH PRES RIDGE WILL BUILD OFF THE SE COAST...
GENERATING A LIGHT TO GENTLE E/SE BREEZE. COMBINED SEAS 3-4FT
NEARSHORE...4-5FT OFFSHORE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 67 63 76 67 / 50 30 50 40
MCO 75 62 81 65 / 50 30 50 40
MLB 76 67 78 70 / 50 20 60 50
VRB 80 68 79 69 / 50 20 60 50
LEE 73 60 79 65 / 50 30 50 40
SFB 73 61 79 66 / 50 30 50 40
ORL 76 62 81 66 / 50 30 50 40
FPR 81 68 79 69 / 50 20 60 50
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR WATERS
FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO 60
NM OFFSHORE.
&&
$$
SHORT TERM/AVIATION...KELLY
LONG TERM/IMPACT WX...BRAGAW
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
411 AM EDT SAT APR 20 2013
.DISCUSSION...
TODAY...A THIN BAND OF SHOWERS ACCOMPANYING A COLD FRONT...
STRETCHING FROM DAYTONA BEACH TO TAMPA...WILL SLOWLY CROSS EC FL
AND SETTLE OVER SOUTH FLORIDA BY EVE. SOME HEATING SHOULD OCCUR
SOUTH OF ORLANDO PRIOR TO FRONTAL PASSAGE THIS MORNING AND EARLY
AFTERNOON WHICH SHOULD PRODUCE A BETTER CHANCE FOR DEEP CONVECTION
(THUNDER). WILL HOLD ONTO SCATTERED SHOWERS ACROSS THE NORTH EVEN
AFTER THE BAND MOVES THROUGH AS A MID LEVEL DISTURBANCE CROSSES
NORTH FLORIDA LATER TODAY AND THIS EVENING. MOS GUIDANCE POPS LOOK
TOO HIGH THOUGH AND HAVE DRAWN 50 POPS MOST AREAS. IN FACT...THINK
COVERAGE SHOULD BE A LITTLE HIGHER ACROSS THE SOUTHERN 1/3 OF
FA...WITH 60 POPS.
TEMPERATURES ARE TRICKY TODAY ESP ACROSS THE NORTH. IN SOME PLACES
THE HIGH MAY OCCUR EARLY THIS MORNING JUST BEFORE FRONTAL PASSAGE.
NORTH WINDS 15 MPH AND WIDESPREAD LOW CLOUDS BEHIND THE FRONT WILL
LIMIT SFC HEATING. FOR EXAMPLE...DAYTONA BEACH WILL LIKELY FALL
INTO THE 60S BEHIND THE FRONT AND NOT CLIMB BACK OUT. ON THE OTHER
HAND...MAX TEMPS SHOULD REACH THE MID 80S AROUND LAKE OKEECHOBEE/
MARTIN COUNTY.
TONIGHT...FRONT IS FORECAST TO HANG UP JUST TO OUR SOUTH BUT
CONSIDERABLE MOISTURE WILL REMAIN OVER THE AREA. THERE MAY BE
SOME RESIDUAL SHOWERS ACROSS THE NORTH ASSOCD WITH DEPARTING MID
LEVEL SHORTWAVE AND UPPER JET. SO WILL HOLD ONTO 30 POPS FOR
SHOWERS IN LAKE AND VOLUSIA IN THE EVENING. PERSISTENT ONSHORE
FLOW WILL REQUIRE A 20 POP ALONG THE COAST MAINLY FOR POTENTIAL
FOR A FEW BANDS TO SET UP AND CROSS THE COAST.
SUN-MON...
UNSEASONABLE WET WX PATTERN FOR CENTRAL FL...GIVEN THAT APR IS
CLIMATOLOGICALLY THE DRIEST MONTH OF THE YEAR. A COLD FRONT
EXTENDING FROM THE MID ATLC TO THE YUCATAN PENINSULA WILL GRIND TO A
HALT AGAINST A LARGE HI PRES RIDGE OVER THE WRN ATLC. DEEP MOISTURE
POOLING WITHIN THE FRONTAL TROF WILL MERGE WITH RELATIVELY HIGH
MOISTURE OVER THE WRN ATLC/NW CARIB...ALLOWING PWAT VALUES TO REACH
AS HIGH AS 1.5"-1.7" ALONG THE TREASURE COAST. LOWER PWATS
(1.3"-1.5") ALONG AND N OF THE I-4 CORRIDOR AS POST FRONTAL DRY AIR
WORKS ITS WAY DOWN THE PENINSULA.
H30-H20 LIFTING JET OVER THE ERN CONUS/NRN GOMEX WILL GENERATE
STRONG UPR LVL DIVERGENCE ACRS THE REGION. UPSTREAM MID LVL ENERGY
IS RATHER SPARSE AS THE LATEST RUC ANALYSIS SHOWS LITTLE IN THE WAY
OF ORGANIZED H85-H50 VORTICITY OVER THE SRN TIER STATES. OMEGA LIFT
ALONG THE FRONTAL BOUNDARY...HOWEVER...SHOULD PROVIDE SUFFICIENT MID
LVL SUPPORT TO KEEP POPS AOA 50PCT. WILL GO WITH 50 POPS ALONG AND N
OF I-4...60 POPS TO THE S DUE TO DEEPER AND MORE ABUNDANT MOISTURE.
WILL KEEP THUNDER IN THE SLGT CHC CATEGORY TUE TO THE LACK OF
LOW/MID LVL INSTABILITY.
NE BREEZE WILL PREVAIL...ALLOWING OCEAN MODIFIED AIR TO ADVECT ACRS
THE CENTRAL PENINSULA. MAX TEMPS IN THE U70S/L80S ALONG THE COAST...
L/M80S INTERIOR. MIN TEMPS M/U60S ALONG THE COAST...L/M60S INTERIOR.
TUE-FRI...
UPDATE TO FOLLOW.
&&
.AVIATION...
FRONT WILL PRESS E/SE AND CROSS LEE/DAB/SFB/MCO BY 8 AM...FPR/SUA
BY 18Z. THIN BAND OF SHRA WILL ACCOMPANY THE FRONT WITH SCATTERED
SHRA/ISOLATED TSRA POSSIBLE AHEAD OF THE FRONT WHERE SFC HEATING
CAN OCCUR SOUTH OF MCO. PRIMARY IMPACT WILL BE PREVAILING MVFR
CIGS BEHIND THE FRONT WITH TEMPO IFR CIGS POSS ESP THROUGH 13Z MCO
NORTHWARD. THERE SHOULD BE A PERIOD OF VFR CIGS DURING THE AFTN
AND EARLY EVE ACROSS MANY TERMINALS BUT EXPECT PREVAILING MVFR
CIGS TO RETURN AFT 00Z.
&&
.MARINE...
TODAY...AS EXPECTED THE SOUTHERLY FLOW HAS WEAKENED A BIT AS PRES
GRAD BECOMES BAGGY ASSOCD WITH FRONTAL ZONE. BUT A SURGE OF NORTH
WINDS WILL OVERSPREAD THE NORTHERN WATERS EARLY THIS MORNING
BEHIND THE FRONT SO HAVE RAISED SMALL CRAFT ADVISORY FOR THE
OFFSHORE VOLUSIA WATERS FOR 20 KNOTS. CLOSER TO THE COAST AND TO
THE SOUTH EXPECT 15-20 KNOTS SO WILL HEADLINE CAUTION. BUT
CONDITIONS WILL BE QUITE UNFAVORABLE ESPECIALLY IN THE GULF
STREAM. IN ADDITION...A BAND OF SHOWERS WILL PUSH OFFSHORE ASSOCD
WITH THE FRONT WITH A FEW STORMS PUSHING OFFSHORE BREVARD TO THE
TREASURE COAST.
TONIGHT...WEAK FRONTAL TROUGH IS FORECAST TO STALL JUST TO THE
SOUTH AND EAST OF THE OUR COASTAL WATERS. THE NORTH TO NORTHEAST
PRES GRAD WILL SUPPORT 15 KNOTS SO WILL LIKELY NEED A CAUTION IN
THE GULF STREAM WITH SEAS UP TO 6 FT.
SUN-SUN NIGHT...A STRONG HIGH PRES RIDGE WILL BUILD ACRS THE ERN
CONUS...GENERATING A MODERATE TO FRESH NE BREEZE. WINDS BCMG A LIGHT
TO GENTLE SE BREEZE S OF SEBASTIAN INLET AFT SUNSET AS AN INVERTED
TROF BEGINS TO FORM OVER S FL ALONG A STALLED FRONTAL BNDRY.
SCT/NMRS SHRAS AND ISOLD TSRAS. SEAS BUILDING TO 6-8FT N OF
SEBASTIAN INLET...4-6FT TO THE SOUTH.
MON-MON NIGHT...THE HIGH PRES RIDGE WILL LIFT INTO THE CANADIAN
MARITIMES...TRAILING ITS RIDGE AXIS DOWN THE ERN CONUS AND INTO THE
LWR MS VALLEY. A WEAK LOW WILL DVLP OFF THE CAROLINA COAST AND
INTERACT WITH THE RIDGE...GENERATING A MODERATE TO FRESH NE BREEZE N
OF SEBASTIAN INLET. S OF THE INLET PGRAD WILL BE WEAKER DUE TO THE
FURTHER PROXIMITY TO THE DLVPG LOW...GENTLE TO MODERATE E/NE BREEZE
WILL RESULT. SEAS 6-8FT N OF SEBASTIAN INLET...4-6FT TO THE SOUTH.
TUE-TUE NIGHT...WINDS WILL DIMINISH AS THE LOW LIFTS UP THE ERN
SEABOARD...BCMG A GENTLE TO MODERATE NE BREEZE AREAWIDE BY LATE
AFTN. PERSISTENT E/NERLY FETCH OVER THE WRN ATLC WILL PUSH A SWELL
INTO THE E FL COAST...KEEPING SEAS 4-6FT NEARSHORE AND 5-7FT
OFFSHORE.
WED-WED NIGHT...A HIGH PRES RIDGE WILL BUILD OFF THE SE COAST...
GENERATING A LIGHT TO GENTLE E/SE BREEZE. COMBINED SEAS 3-4FT
NEARSHORE...4-5FT OFFSHORE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 67 63 76 67 / 50 30 50 40
MCO 75 62 81 65 / 50 30 50 40
MLB 76 67 78 70 / 50 20 60 50
VRB 80 68 79 69 / 50 20 60 50
LEE 73 60 79 65 / 50 30 50 40
SFB 73 61 79 66 / 50 30 50 40
ORL 76 62 81 66 / 50 30 50 40
FPR 81 68 79 69 / 50 20 60 50
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR WATERS
FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO 60
NM OFFSHORE.
&&
$$
SHORT TERM...KELLY
LONG TERM....BRAGAW
AREA FORECAST DISCUSSION
NWS MIAMI FL
125 AM EDT SAT APR 20 2013
.AVIATION...
MOSTLY VFR IS EXPECTED THROUGH THE FORECAST BUT BRIEF MVFR CIGS
MAY OCCUR EARLY AS SCATTERED SHOWERS MOVE TO THE NORTH OVER THE
ATLANTIC AND A FEW MOVE ONSHORE NEAR THE EAST COAST TERMINALS.
MOISTURE AND INSTABILITY WILL BE ON THE INCREASE THROUGH THE DAY
SO SOME CONVECTION IS EXPECTED AFT 18Z WITH STEERING MOTION TAKING
THE CELLS TOWARDS THE EAST COAST. SURFACE WIND WILL GENERALLY BE
SSE WITH A GULF SEA BREEZE AFT 16Z. COLD FRONT WILL SAG SOUTHWARD
AND MAY MOVE FAR ENOUGH SOUTH TO ALLOW SURFACE FLOW AT KPBI TO
BECOME NE LATE IN THE DAY.
KOB
&&
.PREV DISCUSSION... /ISSUED 814 PM EDT FRI APR 19 2013/
AVIATION...
OVERNIGHT SHOWERS WILL REMAIN POSSIBLE AS A COLD FRONT APPROACHES
THE LOCAL AREA TONIGHT INTO SATURDAY. ALTHOUGH THERE REMAINS SOME
UNCERTAINTY REGARDING THE OVERNIGHT COVERAGE DUE MODEL DIFFERENCES
BETWEEN THE HRRR AND WRF GUIDANCE...WE WILL KEEP LATE NIGHT/EARLY
MORNING VCSH IN THIS PACKAGE ALONG THE EAST COAST AND UPGRADE AS
NECESSARY. BRIEF PERIODS WITH MVFR CIGS/VSBYS CAN`T BE RULED OUT
AS THESE SHOWERS DEVELOP AND SPREAD ASHORE THROUGH THIS TIME.
LATER TOMORROW...WINDS WILL BEGIN TO SHIFT TO THE NNW TO NNE AT
APF AND POSSIBLY PBI THROUGH THE AFTERNOON PERIOD AS THE FRONT
MAKES ITS WAY INTO THE AREA. FARTHER SOUTH ALONG THE EAST COAST
ALONG AND AHEAD OF THE BOUNDARY...TEMPOS FOR POTENTIAL TSTMS HAVE
BEEN INCLUDED.
PREV DISCUSSION... /ISSUED 655 PM EDT FRI APR 19 2013/
UPDATE...
THERE HAS BEEN JUST ONE LONE CLOUD TO GROUND LIGHTNING STRIKE
THIS AFTERNOON...AND IT OCCURRED OVER THE PAST HOUR. HIGH RES
MODELS INDICATE THAT THE ACTIVITY OVER INLAND COLLIER...HENDRY AND
GLADES COUNTIES WILL TAPER OFF A FEW HOURS AFTER SUNSET. ISOLATED
TO SCATTERED SHOWERS ARE EXPECTED OVER THE ATLANTIC WATERS...AND
THESE SHOWERS WILL MAKE THEIR WAY TOWARDS THE EAST COAST. SO LEFT
THE CHANCE OF SHOWERS FOR THE EAST COAST...AND LOWERED POPS FOR
THE REST OF THE REGION. A COLD FRONT IS EXPECTED TO STALL OVER
SOUTH CENTRAL FLORIDA LATE TONIGHT INTO THE DAY ON SATURDAY...WITH
INCREASING RAIN CHANCES FOR SOUTH FLORIDA THIS WEEKEND. LOCALLY
HEAVY RAINFALL...GUSTY WINDS...AND FREQUENT CLOUD TO GROUND
LIGHTNING ARE THE MAIN THREATS ON SATURDAY...WITH THE BEST CHANCE
OF STORMS FOR THE EASTERN HALF OF THE REGION. STRONG STORMS MAY
BE POSSIBLE ON SUNDAY AS TEMPERATURES ALOFT COOL...WITH
HAIL...LOCALLY HEAVY RAINFALL...AND STRONG GUSTY WINDS THE MAIN
THREATS.
PREV DISCUSSION... /ISSUED 338 PM EDT FRI APR 19 2013/
UPDATE...
QUICK UPDATE TO ADD A HIGH RISK OF RIP CURRENTS AT THE EAST COAST
BEACHES. OBSERVATIONS SHOW SOUTHEAST WINDS AROUND 20 MPH...AND
MIAMI BEACH OCEAN RESCUE REPORTED RESCUES DUE TO RIP CURRENTS THIS
AFTERNOON. THE HIGH RISK OF RIPS IS IN EFFECT UNTIL 9 PM THIS
EVENING. WINDS ARE FORECAST TO BE MORE PARALLEL TO THE COAST AND
WEAKER ON SATURDAY AHEAD OF THE WEAKENING FRONTAL BOUNDARY.
PREV DISCUSSION... /ISSUED 239 PM EDT FRI APR 19 2013/
DISCUSSION...
DEEPER MOISTURE CONTINUES TO SPREAD ACROSS THE SOUTH FLORIDA
PENINSULA THIS AFTERNOON AHEAD OF AN APPROACHING COLD FRONT. THIS
HAS ALLOWED SCATTERED SHOWERS TO CONTINUE TO DOT THE AREA EARLY
THIS AFTERNOON MAINLY ACROSS THE INTERIOR WHERE TEMPERATURES ARE
CURRENTLY RUNNING SEVERAL DEGREES WARMER THAN COASTAL AREAS.
LATEST GUIDANCE KEEPS THESE SHOWERS ACROSS NORTHERN INTERIOR AREAS
THROUGH THE REMAINDER OF THE AFTERNOON AND INTO THE EARLY EVENING.
THE COLD FRONT IS STILL EXPECTED TO PUSH INTO THE SOUTH FLORIDA AREA
SATURDAY MORNING AND STALL AROUND THE LAKE OKEECHOBEE REGION. THE
STALLED BOUNDARY COMBINED WITH DECENT INSTABILITY...LIFTED INDICES
-2C TO -4C ALONG WITH SBCAPE VALUES AROUND 1400 J/KG...WILL RESULT
IN SHOWERS AND THUNDERSTORMS AREA WIDE SATURDAY AFTERNOON. COULD NOT
RULE OUT A FEW STRONG STORMS BUT BELIEVE MID LEVEL RIDGING WILL STAY
FAIRLY STRONG THROUGH THE PEAK HEATING HOURS WHICH SHOULD INHIBIT
WIDESPREAD STRONG TO SEVERE THUNDERSTORMS.
BY SUNDAY HOWEVER UPPER RIDGING BEGINS TO BREAK DOWN ACROSS THE AREA
AS A LONGWAVE TROUGH BEGINS TO SWEEP THROUGH THE DEEP SOUTH. THIS
WILL ALLOW FOR BETTER COOLING ALOFT. MODEL SOUNDINGS SUNDAY DEPICT
500 MB TEMPERATURES AROUND -12C...DOWN FROM -8C ON SATURDAY. THIS
COMBINED WITH THE STALLED FRONT LINGERING ACROSS THE AREA WILL
ENHANCE SHOWER AND THUNDERSTORM DEVELOPMENT ACROSS THE AREA. A FEW
STORMS COULD BE STRONG AND COULD NOT RULE OUT AN ISOLATED SEVERE
STORM WITH GUSTY WINDS...HAIL...AND HEAVY DOWNPOURS BEING THE MAIN
IMPACTS. SHOWERS AND POSSIBLY A FEW THUNDERSTORMS SHOULD LINGER
THROUGH THE EVENING AND INTO THE OVERNIGHT HOURS AS A FEW MID LEVEL
DISTURBANCES SWING THROUGH THE AREA.
MODELS DO INDICATE A REMNANT TROUGH FROM THE STALLED FRONT LINGERING
AROUND THE AREA THROUGH MONDAY WHICH WILL KEEP CHANCES FOR SHOWERS
AND THUNDERSTORMS THROUGH MONDAY. THERMODYNAMICS SHOULD BE SIMILAR
MONDAY AFTERNOON AS OVER THE WEEKEND...SO CAN/T RULE OUT A FEW
STRONG STORMS AGAIN DURING PEAK HEATING HOURS.
A PREVAILING EASTERLY FLOW WILL RETURN TUESDAY THROUGH WEDNESDAY
WITH SLIGHT CHANCES OF SEA BREEZE INDUCED SHOWERS AND THUNDERSTORMS
EACH DAY. A WEAK COLD FRONT WILL PUSH INTO THE AREA THURSDAY BUT
SHOULD DO LITTLE MORE THAN DECREASE TEMPERATURES A FEW DEGREES.
MARINE...
WINDS AND SEAS MAINLY EXPECTED TO BE BELOW ADVISORY LEVELS THROUGH
THE PERIOD. WINDS AND SEAS COULD BE LOCALLY HIGHER IN OR NEAR ANY
THUNDERSTORMS THAT DEVELOP OVER THE WEEKEND.
FIRE WEATHER...
MINIMUM RELATIVE HUMIDITY VALUES SHOULD STAY ABOVE CRITICAL
THRESHOLDS THROUGH THE PERIOD WITH PLENTY OF LOW LEVEL MOISTURE IN
PLACE. A FEW STRONG STORMS WILL BE POSSIBLE BOTH SATURDAY AND
SUNDAY AS A COLD FRONT STALLS ACROSS THE AREA.
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
632 PM EDT SAT APR 20 2013
.SYNOPSIS...
A STATIONARY FRONT WILL LINGER OFF THE SOUTHEAST COAST INTO EARLY
NEXT WEEK...AS HIGH PRESSURE BUILDS FROM THE NORTH. A COLD FRONT
WILL MOVE ACROSS THE AREA WEDNESDAY OR THURSDAY...FOLLOWED BY HIGH
PRESSURE LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
EARLY SATURDAY EVENING...BACK EDGE OF MID/HIGH LEVEL CLOUD SHIELD
CONTINUED TO STREAM OVER COASTAL COUNTIES BUT WAS POISED TO
ADVANCE OFFSHORE...LEAVING MAINLY CLEAR SKIES ONLY PUNCTUATED BY
ADDITIONAL CIRRUS PUSHING INTO THE REGION FROM THE WEST OVERNIGHT.
ONGOING FORECASTS REMAINED IN DECENT SHAPE AND REQUIRED ONLY
MINOR ADJUSTMENTS TO HOUR;LY PARAMETERS THIS EVENING.
LARGE HIGH PRES WL MOVE INTO THE OHIO VALLEY TNGT WHILE XTNDG
WELL TO THE S. RAP FCST SOUNDINGS SUGGEST THE BNDRY LYR WL GRADUALLY
DECOUPLE THIS EVNG EVENTUALLY YIELDING A LIGHT/CALM WND REGIME.
THIS COUPLED WITH CLR SKIES AND LOW DEWPTS WL SUPPORT A DECENT
RADIATIONAL SETUP WITH LOWS DROPPING INTO THE LWR 40S INLAND TO
THE LWR-MID 50S AT THE BEACHES WHERE WNDS WL LIKELY STAY UP A BIT.
IT IS NOT OUT OF THE REALM OF POSSIBILITY THAT A FEW UPR 30S COULD
OCCUR IN SOME OF THE NORMALLY COLDER LOCATIONS SUCH AS ALLENDALE
AND JAMESTOWN. 20/12Z GFS-COOP GUIDANCE IS FCSTG UPR 30S IN
SEVERAL OF THE FAR INLAND STATIONS. FROST IS NOT A CONCERN EVEN IF
UPR 30S WHERE TO OCCUR.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
SUNDAY...A COLD FRONT WILL STALL WELL OFF THE SOUTHEAST COAST SUNDAY
WHILE LARGE SFC HIGH PRESSURE BECOMES CENTERED OVER THE NORTHEASTERN
UNITED STATES. THIS WILL RESULT IN UNSEASONABLY COOL CONDITIONS OVER
THE SOUTHEASTERN UNITED STATES AS BRISK NORTHEAST WINDS DEVELOP IN
RESPONSE TO A TIGHT PRESSURE GRADIENT BETWEEN THE STALLED BOUNDARY
AND HIGH PRESSURE TO THE NORTH. WE COULD SEE A PERIOD OF GUSTY WINDS
BETWEEN 25-30 MPH SUNDAY AFTERNOON AS TEMPS APPROACH THE UPPER 60S
TO AROUND 70...BUT CONDITIONS SHOULD FALL SHORT OF WIND ADVISORY
CRITERIA. CHANCES OF RAIN/SHOWERS WILL THEN INCREASE ALONG COASTAL
COUNTIES THROUGH SUNDAY EVENING AS ISENTROPIC ASCENT AND LOW LVL
MOISTURE INCREASE OVER THE AREA IN RESPONSE TO LOW PRESSURE
DEVELOPING ALONG THE STALLED BOUNDARY OFFSHORE. HAVE MAINTAINED THE
CURRENT PRECIP FORECAST WITH A SLIGHT CHANCE OF SHOWERS INLAND AND
CHANCE OF SHOWERS ALONG COASTAL COUNTIES.
MONDAY AND TUESDAY...CLOUDY AND COOL CONDITIONS WILL LIKELY PERSIST
INTO EARLY NEXT WEEK AS MOISTURE LINGERS ALONG THE WESTERN EDGE OF
LOW PRESSURE DEEPENING ALONG THE SOUTHEAST COAST AND HIGH PRESSURE
WEDGING OVER LAND. A SLIGHT CHANCE OF RAIN/SHOWERS AND GUSTY WINDS
WILL BE POSSIBLE ON MONDAY...MAINLY ALONG COASTAL COUNTIES WHERE
MOISTURE IS GREATEST AND THE PRESSURE GRADIENT REMAINS PINCHED
BETWEEN THE DEPARTING LOW TO THE NORTHEAST AND HIGH PRESSURE OVER
LAND. BY TUESDAY...CONDITIONS WILL GRADUALLY WARM AND DRY UNDER
ZONAL FLOW WHILE SFC HIGH PRESSURE SLIDES TO THE COAST AND THE OFFSHORE
LOW SHIFTS FURTHER NORTH AND EAST AWAY FROM THE REGION. OVERALL HIGH
TEMPS SHOULD REACH THE UPPER 60S TO AROUND 70 ON MONDAY...BEFORE
WARMING INTO THE LOW 70S ON TUESDAY.
LAKE WINDS...STRONG NORTHEAST WINDS ARE EXPECTED SUNDAY AFTERNOON
AND SUNDAY NIGHT AS HIGH PRESSURE BUILDS FROM THE NORTH AND
TEMPERATURES PROFILES BECOME FAVORABLE FOR MIXING OF STRONG
LOW-LEVEL WINDS DOWN OVER THE RELATIVELY WARMER LAKE WATERS.
THUS...A LAKE WIND ADVISORY MAY BE NEEDED DURING THIS TIME.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE WILL BE SLIPPING OFFSHORE TUESDAY NIGHT INTO WEDNESDAY
AS A COLD FRONT APPROACHES FROM THE WEST. THERE IS STILL SOME
UNCERTAINTY REGARDING THE TIMING OF THE COLD FRONTAL PASSAGE
WEDNESDAY OR THURSDAY...AND IT COULD EVEN STALL OUT OVER OR NEAR THE
AREA. FOR NOW WE HAVE KEPT RAIN CHANCES LOW AND MAINLY THROUGH
THURSDAY WITH DRIER CONDITIONS FRIDAY. RAIN CHANCES COULD INCREASE
AGAIN LATER SATURDAY AS ANOTHER COLD FRONT BEGINS TO APPROACH FROM
THE WEST. TEMPERATURES ARE TRICKY AS MUCH DEPENDS ON THE TIMING OF
THE FRONTAL PASSAGE BUT FOR NOW HAVE KEPT THEM NEAR TO BELOW NORMAL.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
VFR IS EXPECTED TO PREVAIL THROUGH THE VALID TAF PERIOD. CLOUDS WILL
CONTINUE TO SHIFT EAST...WITH CLEAR SKIES EXPECTED TONIGHT. MAIN
AVIATION CONCERN WILL BE THE WINDS TOMORROW. A TIGHTENED PRESSURE
GRADIENT WILL RESULT IN GUSTY WINDS DEVELOPING LATE MORNING.
GENERALLY EXPECT NORTHEAST WINDS SUSTAINED AROUND 15 KTS...WITH
GUSTS UP TO AROUND 23 KTS.
EXTENDED AVIATION OUTLOOK....MVFR CIGS EXPECTED BY SUNDAY EVENING
AND COULD POSSIBLY LAST INTO EARLY TUESDAY. BREEZY/GUSTY
CONDITIONS EXPECTED SUNDAY AND MONDAY.
&&
.MARINE...
TONIGHT...N WNDS WL GRADLY VEER TO THE NE AS HIGH PRES BUILDS IN
FROM THE S. SPEEDS WL BEGIN TO STEADILY INCR AFT MIDNGT AS THE
PRES GRADIENT BETWEEN HIGH PRES TO THE N AND THE REMNANT CDFNT
DEGENERATES INTO A SHARPENING COASTAL TROUGH. XPCT NE WINDS OF
15-20 KT TO DOMINATE NEARSHORE WTRS AND 20-25 KT OFFSHORE WTRS
BY SUNRISE SUN. SEAS WL BUILD IN RESPONSE TO THE STRENGTHENING
WINDS...BUILDING TO 3-5 FT NEARSHORE WATERS EDISTO BEACH S...4-6
FT FOR THE CHARLESTON COUNTY COASTAL WATERS AND 5-7 FT OFFSHORE
WATERS. WL HOIST A SMALL CRAFT ADVISORY FOR THE GEORGIA OFFSHORE LEG
BEGINNING AND MIDNIGHT AND THE CHARLESTON COUNTY WATERS BEGINNING
A 5 AM SUNDAY.
SUNDAY THROUGH THURSDAY...MARINE CONDITIONS WILL DETERIORATE DURING
THE BEGINNING OF THE WEEK AS AN ENHANCED PRESSURE GRADIENT DEVELOPS
BETWEEN A STALLING COLD FRONT OFFSHORE AND STRONG HIGH PRESSURE
BUILDING OVER LAND. STRONG COLD AIR ADVECTION FROM THE
NORTH/NORTHWEST ALONG WITH 40-45 KT 1000 MB GEOSTROPHIC WINDS
SUGGEST GALE FORCE WIND GUSTS BETWEEN 35-40 KT OVER ALL WATERS
SUNDAY AFTERNOON INTO EARLY MONDAY. THE BEST CHANCE OF GALE FORCE
WINDS WILL REMAIN OVER WARMER WATER TEMPS IN NORTHERN SC WATERS AND
OUTER GEORGIA WATERS. SEAS MAY ALSO APPROACH 10-12 FT BEYOND 10 NM
FROM THE COAST SUNDAY NIGHT INTO EARLY MONDAY. CONDITIONS SHOULD
DROP BELOW ADVISORY LEVELS FOR MUCH OF THE NEARSHORE WATERS MONDAY
NIGHT AND ACROSS THE OUTER WATERS TUESDAY. A COLD FRONT WILL LIKELY
PUSH THROUGH THE WATERS WEDNESDAY OR THURSDAY BUT CONDITIONS LOOK TO
REMAIN BELOW ADVISORY LEVELS.
RIP CURRENTS...THE COMBINATION OF INCREASING WINDS ALONG THE
BEACHES AND BUILDING SURF WILL SUPPORT A MODERATE RISK FOR RIP
CURRENTS ALONG THE SOUTH CAROLINA BEACHES AND A HIGH RISK FOR THE
GEORGIA BEACHES ON SUNDAY. THERE ARE SOME INDICATIONS IN THE
LATEST WW4 OUTPUT THAT THE UNDERLYING SWELL PERIOD COULD REACH AS
HIGH AS 10 SECONDS. SHOULD THIS VERIFY...THEN THE RISK WOULD TIP
INTO THE HIGH CATEGORY FOR THE SOUTH CAROLINA BEACHES AS WELL. AN
ENHANCED RISK FOR RIP CURRENTS WILL PERSIST FOR THE NEXT SEVERAL
DAYS.
&&
.TIDES/COASTAL FLOODING...
STRONG NORTHEAST WINDS SUNDAY AND SUNDAY NIGHT WILL LEAD TO
BUILDING SEAS...ROUGH SURF...BEACH EROSION AND SHALLOW COASTAL
FLOODING. A COASTAL FLOOD ADVISORY AND HIGH SURF ADVISORY MAY
EVENTUALLY BE NEEDED.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...HIGH RISK FOR RIP CURRENTS FROM SUNDAY MORNING THROUGH SUNDAY
EVENING FOR GAZ117-119-139-141.
SC...NONE.
MARINE...GALE WATCH FROM SUNDAY MORNING THROUGH MONDAY MORNING FOR
AMZ330-352-354.
GALE WATCH FROM SUNDAY MORNING THROUGH MONDAY AFTERNOON FOR
AMZ350-374.
SMALL CRAFT ADVISORY FROM 5 AM TO 11 AM EDT SUNDAY FOR AMZ350.
SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 11 AM EDT SUNDAY
FOR AMZ374.
&&
$$
SYNOPSIS...
NEAR TERM...SPR/ST
SHORT TERM...DPB
LONG TERM...RJB
AVIATION...SPR
MARINE...SPR/DPB/ST
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
309 PM EDT SAT APR 20 2013
...HIGH RISK FOR RIP CURRENTS ALONG THE BEACHES OF NORTH COASTAL
GEORGIA SUNDAY...
.SYNOPSIS...
A COLD FRONT WILL STALL OFF THE SOUTHEAST COAST AND LINGER INTO EARLY
NEXT WEEK...AS HIGH PRESSURE BUILDS FROM THE NORTH. ANOTHER COLD
FRONT WILL MOVE ACROSS THE AREA WEDNESDAY OR THURSDAY...FOLLOWED
BY HIGH PRESSURE LATE IN THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE BACK EDGE OF THE CLRG LINE WL CONT TO MOVE SLOWLY E FOR THE
REMAINDER OF THE AFTN HRS WITH MAINLY CLR SKIES XPCTD TO DOMINATE
FOR THE OVRNGT PERIOD. LARGE HIGH PRES WL MOVE INTO THE OHIO
VALLEY TNGT WHILE XTNDG WELL TO THE S. RAP FCST SOUNDINGS SUGGEST
THE BNDRY LYR WL GRADLY DECOUPLE THIS EVNG EVENTUALLY YIELDING A
LIGHT/CALM WND REGIME. THIS COUPLED WITH CLR SKIES AND LOW DEWPTS
WL SUPPORT A DECENT RADIATIONAL SETUP WITH LOWS DROPPING INTO THE
LWR 40S INLAND TO THE LWR-MID 50S AT THE BEACHES WHERE WNDS WL
LIKELY STAY UP A BIT. IT IS NOT OUT OF THE REALM OF POSSIBILITY
THAT A FEW UPR 30S COULD OCCUR IN SOME OF THE NORMALLY COLDER
LOCATIONS SUCH AS ALLENDALE AND JAMESTOWN. 20/12Z GFS-COOP
GUIDANCE IS FCSTG UPR 30S IN SEVERAL OF THE FAR INLAND STATIONS.
FROST IS NOT A CONCERN EVEN IF UPR 30S WHERE TO OCCUR.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
SUNDAY...A COLD FRONT WILL STALL WELL OFF THE SOUTHEAST COAST SUNDAY
WHILE LARGE SFC HIGH PRESSURE BECOMES CENTERED OVER THE NORTHEASTERN
UNITED STATES. THIS WILL RESULT IN UNSEASONABLY COOL CONDITIONS OVER
THE SOUTHEASTERN UNITED STATES AS BRISK NORTHEAST WINDS DEVELOP IN
RESPONSE TO A TIGHT PRESSURE GRADIENT BETWEEN THE STALLED BOUNDARY
AND HIGH PRESSURE TO THE NORTH. WE COULD SEE A PERIOD OF GUSTY WINDS
BETWEEN 25-30 MPH SUNDAY AFTERNOON AS TEMPS APPROACH THE UPPER 60S
TO AROUND 70...BUT CONDITIONS SHOULD FALL SHORT OF WIND ADVISORY
CRITERIA. CHANCES OF RAIN/SHOWERS WILL THEN INCREASE ALONG COASTAL
COUNTIES THROUGH SUNDAY EVENING AS ISENTROPIC ASCENT AND LOW LVL
MOISTURE INCREASE OVER THE AREA IN RESPONSE TO LOW PRESSURE
DEVELOPING ALONG THE STALLED BOUNDARY OFFSHORE. HAVE MAINTAINED THE
CURRENT PRECIP FORECAST WITH A SLIGHT CHANCE OF SHOWERS INLAND AND
CHANCE OF SHOWERS ALONG COASTAL COUNTIES.
MONDAY AND TUESDAY...CLOUDY AND COOL CONDITIONS WILL LIKELY PERSIST
INTO EARLY NEXT WEEK AS MOISTURE LINGERS ALONG THE WESTERN EDGE OF
LOW PRESSURE DEEPENING ALONG THE SOUTHEAST COAST AND HIGH PRESSURE
WEDGING OVER LAND. A SLIGHT CHANCE OF RAIN/SHOWERS AND GUSTY WINDS
WILL BE POSSIBLE ON MONDAY...MAINLY ALONG COASTAL COUNTIES WHERE
MOISTURE IS GREATEST AND THE PRESSURE GRADIENT REMAINS PINCHED
BETWEEN THE DEPARTING LOW TO THE NORTHEAST AND HIGH PRESSURE OVER
LAND. BY TUESDAY...CONDITIONS WILL GRADUALLY WARM AND DRY UNDER
ZONAL FLOW WHILE SFC HIGH PRESSURE SLIDES TO THE COAST AND THE OFFSHORE
LOW SHIFTS FURTHER NORTH AND EAST AWAY FROM THE REGION. OVERALL HIGH
TEMPS SHOULD REACH THE UPPER 60S TO AROUND 70 ON MONDAY...BEFORE
WARMING INTO THE LOW 70S ON TUESDAY.
LAKE WINDS...STRONG NORTHEAST WINDS ARE EXPECTED SUNDAY AFTERNOON
AND SUNDAY NIGHT AS HIGH PRESSURE BUILDS FROM THE NORTH AND
TEMPERATURES PROFILES BECOME FAVORABLE FOR MIXING OF STRONG
LOW-LEVEL WINDS DOWN OVER THE RELATIVELY WARMER LAKE WATERS.
THUS...A LAKE WIND ADVISORY MAY BE NEEDED DURING THIS TIME.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
HIGH PRESSURE WILL BE SLIPPING OFFSHORE TUESDAY NIGHT INTO WEDNESDAY
AS A COLD FRONT APPROACHES FROM THE WEST. THERE IS STILL SOME
UNCERTAINTY REGARDING THE TIMING OF THE COLD FRONTAL PASSAGE
WEDNESDAY OR THURSDAY...AND IT COULD EVEN STALL OUT OVER OR NEAR THE
AREA. FOR NOW WE HAVE KEPT RAIN CHANCES LOW AND MAINLY THROUGH
THURSDAY WITH DRIER CONDITIONS FRIDAY. RAIN CHANCES COULD INCREASE
AGAIN LATER SATURDAY AS ANOTHER COLD FRONT BEGINS TO APPROACH FROM
THE WEST. TEMPERATURES ARE TRICKY AS MUCH DEPENDS ON THE TIMING OF
THE FRONTAL PASSAGE BUT FOR NOW HAVE KEPT THEM NEAR TO BELOW NORMAL.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
VFR IS EXPECTED TO PREVAIL THROUGH THE VALID TAF PERIOD. CLOUDS WILL
CONTINUE TO SHIFT EAST...WITH CLEAR SKIES EXPECTED TONIGHT. MAIN
AVIATION CONCERN WILL BE THE WINDS TOMORROW. A TIGHTENED PRESSURE
GRADIENT WILL RESULT IN GUSTY WINDS DEVELOPING LATE MORNING.
GENERALLY EXPECT NORTHEAST WINDS SUSTAINED AROUND 15 KTS...WITH
GUSTS UP TO AROUND 23 KTS.
EXTENDED AVIATION OUTLOOK....MVFR CIGS EXPECTED BY SUNDAY EVENING
AND COULD POSSIBLY LAST INTO EARLY TUESDAY. BREEZY/GUSTY
CONDITIONS EXPECTED SUNDAY AND MONDAY.
&&
.MARINE...
TONIGHT...N WNDS WL GRADLY VEER TO THE NE AS HIGH PRES BUILDS IN
FROM THE S. SPEEDS WL BEGIN TO STEADILY INCR AFT MIDNGT AS THE
PRES GRADIENT BETWEEN HIGH PRES TO THE N AND THE REMNANT CDFNT
DEGENERATES INTO A SHARPENING COASTAL TROUGH. XPCT NE WINDS OF
15-20 KT TO DOMINATE NEARSHORE WTRS AND 20-25 KT OFFSHORE WTRS
BY SUNRISE SUN. SEAS WL BUILD IN RESPONSE TO THE STRENGTHENING
WINDS...BUILDING TO 3-5 FT NEARSHORE WATERS EDISTO BEACH S...4-6
FT FOR THE CHARLESTON COUNTY COASTAL WATERS AND 5-7 FT OFFSHORE
WATERS. WL HOIST A SMALL CRAFT ADVISORY FOR THE GEORGIA OFFSHORE LEG
BEGINNING AND MIDNIGHT AND THE CHARLESTON COUNTY WATERS BEGINNING
A 5 AM SUNDAY.
SUNDAY THROUGH THURSDAY...MARINE CONDITIONS WILL DETERIORATE DURING
THE BEGINNING OF THE WEEK AS AN ENHANCED PRESSURE GRADIENT DEVELOPS
BETWEEN A STALLING COLD FRONT OFFSHORE AND STRONG HIGH PRESSURE
BUILDING OVER LAND. STRONG COLD AIR ADVECTION FROM THE
NORTH/NORTHWEST ALONG WITH 40-45 KT 1000 MB GEOSTROPHIC WINDS
SUGGEST GALE FORCE WIND GUSTS BETWEEN 35-40 KT OVER ALL WATERS
SUNDAY AFTERNOON INTO EARLY MONDAY. THE BEST CHANCE OF GALE FORCE
WINDS WILL REMAIN OVER WARMER WATER TEMPS IN NORTHERN SC WATERS AND
OUTER GEORGIA WATERS. SEAS MAY ALSO APPROACH 10-12 FT BEYOND 10 NM
FROM THE COAST SUNDAY NIGHT INTO EARLY MONDAY. CONDITIONS SHOULD
DROP BELOW ADVISORY LEVELS FOR MUCH OF THE NEARSHORE WATERS MONDAY
NIGHT AND ACROSS THE OUTER WATERS TUESDAY. A COLD FRONT WILL LIKELY
PUSH THROUGH THE WATERS WEDNESDAY OR THURSDAY BUT CONDITIONS LOOK TO
REMAIN BELOW ADVISORY LEVELS.
RIP CURRENTS...THE COMBINATION OF INCREASING WINDS ALONG THE
BEACHES AND BUILDING SURF WILL SUPPORT A MODERATE RISK FOR RIP
CURRENTS ALONG THE SOUTH CAROLINA BEACHES AND A HIGH RISK FOR THE
GEORGIA BEACHES ON SUNDAY. THERE ARE SOME INDICATIONS IN THE
LATEST WW4 OUTPUT THAT THE UNDERLYING SWELL PERIOD COULD REACH AS
HIGH AS 10 SECONDS. SHOULD THIS VERIFY...THEN THE RISK WOULD TIP
INTO THE HIGH CATEGORY FOR THE SOUTH CAROLINA BEACHES AS WELL. AN
ENHANCED RISK FOR RIP CURRENTS WILL PERSIST FOR THE NEXT SEVERAL
DAYS.
&&
.TIDES/COASTAL FLOODING...
STRONG NORTHEAST WINDS SUNDAY AND SUNDAY NIGHT WILL LEAD TO
BUILDING SEAS...ROUGH SURF...BEACH EROSION AND SHALLOW COASTAL
FLOODING. A COASTAL FLOOD ADVISORY AND HIGH SURF ADVISORY MAY
EVENTUALLY BE NEEDED.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...HIGH RISK FOR RIP CURRENTS FROM SUNDAY MORNING THROUGH SUNDAY
EVENING FOR GAZ117-119-139-141.
SC...NONE.
MARINE...GALE WATCH FROM SUNDAY MORNING THROUGH MONDAY MORNING FOR
AMZ330-352-354.
GALE WATCH FROM SUNDAY MORNING THROUGH MONDAY AFTERNOON FOR
AMZ350-374.
SMALL CRAFT ADVISORY FROM 5 AM TO 11 AM EDT SUNDAY FOR AMZ350.
SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 11 AM EDT SUNDAY
FOR AMZ374.
&&
$$
ST/DPB/ECT
AREA FORECAST DISCUSSION...UPDATED
NWS COLUMBIA SC
1017 AM EDT SAT APR 20 2013
.SYNOPSIS...
THE COLD FRONT THAT HAS MOVED THROUGH THE FORECAST AREA WILL STALL
JUST OFF THE COAST TODAY. THE FRONT WILL REMAIN JUST OFFSHORE
THROUGH MONDAY. HIGH PRESSURE MOVING INTO THE NORTHEAST STATES
WILL RIDGE SOUTHWARD AND INTO THE FORECAST AREA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A COLD FRONT PUSHED ACROSS THE FORECAST AREA OVERNIGHT...SHIFTING
RAIN SHOWERS OFF THE COAST BY THIS MORNING. LATEST VISIBLE SAT
IMAGERY SHOWING LINGERING HIGH CLOUDS ACROSS THE FORECAST AREA
WITH CLEARING ACROSS THE WESTERN CAROLINAS.
THESE HIGHER CLOUDS WILL SLOWLY SHIFT EAST THROUGH THE DAY AS THE
UPPER TROUGH AXIS MOVES EAST ACROSS THE AREA. DRY HIGH PRESSURE
CONTINUES TO BUILD INTO THE REGION FROM THE NORTHWEST WITH
NORTHERLY SURFACE WINDS PREVAILING IN THE LOWEST 3000 FT. 14Z LAPS
AND RUC ANALYSIS SOUNDINGS INDICATE THE SIGNIFICANT DRY AIR
THROUGH THE ATMOSPHERIC COLUMN WITH PRECIPITABLE WATER VALUES DOWN
TO AROUND 0.3 INCHES. DO NOT EXPECT ANY CUMULUS DEVELOPMENT TODAY
WITH THE DRY AIRMASS AND SKIES SHOULD CLEAR FROM WEST TO EAST
THROUGH THE DAY. TEMPERATURES MAY BE A BIT COOLER THAN PREVIOUSLY
THOUGHT DUE TO LINGERING HIGH CLOUDS...ESPECIALLY ACROSS THE
EASTERN PORTIONS OF THE FORECAST AREA. HAVE ADJUSTED MAX
TEMPERATURES DOWN A COUPLE OF DEGREES TO BETTER REFLECT THIS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
HIGH PRESSURE MOVING INTO THE NORTHEAST STATES WILL RIDGE
SOUTHWARD AND INTO THE FORECAST AREA. THE NAM AND GFS KEEP THE AIR
MASS DRY THROUGH TONIGHT. MOISTURE APPEARS TO INCREASE WITH A
DEVELOPING EASTERLY FLOW WITH WEAK ISENTROPIC LIFT FOR SUNDAY AND
SUNDAY NIGHT. THE MODELS KEEP THE MOISTURE SHALLOW AND LIFT WEAK.
MAINTAINED JUST CHANCE POPS SUNDAY NIGHT. THE HIGH TEMPERATURE
GUIDANCE MAY BE TOO WARM SUNDAY BECAUSE OF A DEVELOPING WEDGE
PATTERN. USED THE GUIDANCE CONSENSUS FOR THE LOW TEMPERATURE
FORECAST.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE NAM AND GFS SHOW A WEAK WEDGE PATTERN MONDAY. THE MOISTURE
STILL APPEARS SHALLOW WITH WEAK ISENTROPIC LIFT. THE NAM AND GFS
MOS INDICATE LOW POPS. EXPECT ANY RAIN WILL BE LIGHT. THE
TEMPERATURE GUIDANCE APPEARS TOO WARM BECAUSE OF THE WEDGE
PATTERN. THE WEDGE PATTERN APPEARS TO FURTHER WEAKEN TUESDAY. THE
GFS SHOWS THE NEXT COLD FRONT AFFECTING THE AREA WEDNESDAY INTO
THURSDAY SUPPORTING A CHANCE OF SHOWERS AND THUNDERSTORMS. DRYING
BEHIND THIS FRONT SHOULD DOMINATE FRIDAY.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS EXPECTED THROUGH THE 24 HR FORECAST PERIOD.
HIGH PRESSURE CONTINUES TO BUILD INTO THE REGION WITH NORTHERLY
WINDS THIS MORNING AROUND 10 KNOTS OR SO GRADUALLY DIMINISHING AND
SHIFTING MORE NORTHEASTERLY BY 00Z THROUGH THE OVERNIGHT HOURS.
VFR HIGH CLOUDS WILL GRADUALLY CLEAR FROM WEST TO EAST THROUGH
THE DAY WITH NO AVIATION IMPACTS EXPECTED.
EXTENDED AVIATION OUTLOOK...SOME CIG/VSBY RESTRICTIONS POSSIBLE
SUNDAY NIGHT INTO MONDAY AS A STALLED FRONT OFF THE ATLANTIC COAST
MAY SPREAD CLOUDS AND SOME PRECIPITATION BACK INTO THE AREA. ANOTHER
COLD FRONT WILL CROSS AREA WEDNESDAY WITH CIG/VSBY RESTRICTIONS
POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
NEAR TERM...HC
AVIATION...HC
AREA FORECAST DISCUSSION
NWS BOISE ID
814 PM MDT SUN APR 21 2013
.DISCUSSION...HAVE UPDATED THE FORECAST FOR ISOLATED SHOWERS
ACROSS THE OWYHEE MOUNTAINS THROUGH MIDNIGHT AS RADAR ECHOES
THERE AND THICK CLOUDS INDICATE AT LEAST A SLIGHT CHANCE OF RAIN
/SNOW LEVEL 7K FT/ SHOWERS. HRRR MODEL HAS THIS WELL DEPICTED AS
DO SOME OF THE BIAS CORRECTED MOS/MODEL GUIDANCE POPS. BOISE HIGH
OF 64 WAS RIGHT ON. ISOLATED THUNDERSTORMS TODAY WERE NORTH OF OUR
AREA NEAR A COLD FRONT WHICH BY 8PM HAD MOVED TO OVER NE OREGON...THE
SOUTH PART OF THE IDAHO PANHANDLE...PASSED KSMN TO ACROSS NW WY.
HIGHER PRESSURE OFF THE OREGON COAST COMBINED WITH LOW PRESSURE
CENTERED OVER CENTRAL WY BROUGHT GUSTY WINDS OF 20-30 MPH ACROSS
SE OREGON...25-38 MPH ACROSS THE WESTERN MAGIC VALLEY...AND 10-20
MPH ACROSS THE REST OF SW IDAHO. FRONT WILL DROP ACROSS SW IDAHO
/WITH NUMEROUS SHOWERS ACROSS THE WEST CENTRAL MOUNTAINS/ THROUGH
EARLY MONDAY. LIGHTNING PROBABILITIES ARE MOSTLY ZERO EXCEPT
BRIEFLY ACROSS THE BOISE MOUNTAINS IN THE WEE MORNING HOURS WITH
THE FROPA...TOO SMALL TO MAKE CHANGES TO THE FORECAST. IT WILL BE
COOLER MONDAY WITH LOCALLY VERY WINDY CONDITIONS IN THE AFTERNOON
ACROSS SOUTHERN ELMORE COUNTY INCLUDING THE MOUNTAIN HOME AREA.
&&
.AVIATION...WEST CENTRAL IDAHO MOUNTAINS...ISOLATED SHOWERS WITH
LOCAL MVFR CONDITIONS AND MOUNTAIN OBSCURATION. SNOW LEVEL AROUND
6500 FEET MSL LOWERING TO 4K FEET MSL BY 12Z. ELSEWHERE...VFR
CONDITIONS WITH SCATTERED TO BROKEN MID LEVEL CLOUDS. WEST TO
NORTHWEST SURFACE WINDS 10 KNOTS OR LESS AFTER SUNSET EXCEPT
SUSTAINED WINDS AROUND 15 KNOTS IN THE MAGIC VALLEY. WINDS ALOFT
WILL BE WESTERLY AROUND 30 KNOTS UP THROUGH 10K FEET MSL.
&&
.PREV DISCUSSION...
SHORT TERM...TONIGHT THROUGH TUESDAY...COLD FRONT WILL MOVE
SOUTHWARD THROUGH THE CWA LATE TONIGHT THROUGH MONDAY MORNING.
SCATTERED SHOWERS WILL DEVELOP ALONG THE FRONT AS IT CROSSES THE
BOISE AND WEST CENTRAL MTNS...ENHANCED BY UPSLOPE FLOW OVER THE
HIGHER TERRAIN. MOISTURE WILL SHIFT TO THE EAST AS THE FRONT MOVES
INTO THE VALLEY...SO NOT EXPECTING ANY SHOWERS FROM THE
TREASURE/WESTERN MAGIC VALLEYS SOUTH TO THE NEVADA BORDER. IT ALSO
LOOKS TO BE TOO DRY FOR SHOWERS IN MOST OF SE OREGON...EXCEPT FOR
THE HIGHER TERRAIN IN BAKER COUNTY. THE FRONT WILL BE ACCOMPANIED BY
GUSTY NORTHWEST WINDS...BECOMING WINDY MONDAY AFTERNOON AS A COOLER
DRY AIR MASS SETTLES IN BEHIND THE FRONT. THE COOL DRY
NORTH-NORTHWEST FLOW WILL CONTINUE THROUGH TUESDAY. WINDS WILL BE
LIGHTER ON TUESDAY DUE TO A WEAKER SURFACE PRESSURE GRADIENT. HIGHS
WILL BE 5-10 DEGREES BELOW NORMAL ON MONDAY WITH SLIGHTLY WARMER
TEMPS ANTICIPATED ON TUESDAY.
LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...MODELS CONTINUE TO FAVOR
PERSISTENCE OF THE OFFSHORE RIDGE AND NORTH AMERICAN TROUGH IN THE
LONG TERM. BOTH THE ECMWF AND GFS ENSEMBLE MEANS AGREE ON
MAINTAINING THIS SCENARIO THROUGH SUNDAY. OVER THE NORTHWEST
STATES...THE PATTERN BRIEFLY DE-AMPLIFIES THURSDAY AND FRIDAY...
SHIFTING UPPER LEVEL WINDS FROM NORTHWEST ON WEDNESDAY TO WEST ON
THURSDAY AND FRIDAY...RESULTING IN SLIGHTLY WARMER TEMPERATURES.
MOST OF OUR AREA WILL REMAIN DRY AT LEAST THROUGH FRIDAY.
PRECIPITATION FOR THE WEEKEND IS UNCERTAIN...AS SOLUTIONS DIFFER
CONSIDERABLY IN TIMING SHORTWAVES IN THE WESTERLY FLOW. SO WE ARE
TRENDING POPS TOWARD CLIMATOLOGY FOR FRIDAY NIGHT THROUGH
SUNDAY...WITH THE BEST CHANCE OF SHOWERS OVER THE CENTRAL IDAHO
MOUNTAINS AND LITTLE IF ANY PRECIPITATION IN THE VALLEYS.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
DISCUSSION...VM
AVIATION.....JA
PREV SHORT TERM...BW
PREV LONG TERM....JT/DD
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
220 PM EDT SAT APR 20 2013
.UPDATE...
ISSUED AT 1206 PM EDT SAT APR 20 2013
FAIRLY STRONG NEGATIVE VORTICITY ADVECTION ALOFT IN ASSOCIATION
WITH DEPARTING UPPER LEVEL TROUGH WILL AID LARGE SCALE SUBSIDENCE
THIS AFTERNOON. LACK OF CU FORMATION NOTED FROM NORTHEAST ILLINOIS
INTO FAR NORTHWEST INDIANA IN ASSOCIATION WITH THIS INCREASING
SUBSIDENCE SHOULD EVENTUALLY BECOME THE RULE ACROSS THE LOCAL AREA
LATE THIS AFTERNOON. LINGERING LAKE EFFECT CLOUDINESS WILL
DIMINISH OVER THE NEXT FEW HOURS AS LOW LEVEL FLOW ACROSS SOUTHERN
LAKE MICHIGAN BEGINS TO TRANSITION TO MAINLY A DIVERGENT/ONSHORE
TYPE. CU APPEARS TO BE FAIRLY THICK AND OF GOOD COVERAGE ACROSS
PORTIONS OF EASTERN HALF OF CWA...ALTHOUGH GRADUALLY EXPECTING
THIS CU FIELD TO BECOME LESS VERTICALLY DEVELOPED AND THINNER
THROUGH TIME. DESPITE MAINTENANCE OF LOW LEVEL THERMAL
TROUGH...INCREASED INSOLATION SHOULD SUPPORT HIGHS CLOSE TO THAT
OF GOING FORECAST OR PERHAPS JUST SHORT OF THAT IN SOME INSTANCES.
WITH GOING FORECAST IN GOOD SHAPE...ONLY MADE SOME MARGINAL TWEAKS
TO SKY COVER TO ACCOUNT FOR CURRENT TRENDS...OTHERWISE PREVIOUS
FORECAST KEPT INTACT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM EDT SAT APR 20 2013
SCATTERED SNOW SHOWERS CONTINUE ACROSS THE CWA AT PRESS TIME...AIDED
BY PERSISTENT MOIST CYCLONIC FLOW ASSOCIATED WITH PASSING MIDLEVEL
TROUGH AXIS. HI-RES FORECAST SOUNDINGS ALSO SHOW BOUNDARY LAYER HAS
REMAINED WELL MIXED THROUGH THE OVERNIGHT HOURS...FURTHER SUPPORTING
CONVECTIVE SNOW SHOWERS. QUESTION WILL BE WHETHER OR NOT ACTIVITY
CAN PERSIST BEYOND 12Z. A FEW PREVIOUS RAP MODEL RUNS SUGGESTED
ISOLATED RAIN/SNOW SHOWERS PERSISTING FOR MUCH OF THE MORNING AS ONE
LAST RIBBON OF SHEAR VORTICITY ROTATES THROUGH THE AREA.
HOWEVER...MIDLEVEL HEIGHTS WILL BE CLIMBING QUICKLY BY LATER THIS
MORNING AND NAM BUFR DATA SHOWS LOWER TROPOSPHERIC DRY AIR
INCREASING AS WELL AS A STRENGTHENING SUBSIDENCE INVERSION.
THEREFORE EXPECT LITTLE MORE THAN ISOLATED FLURRIES AFTER 12Z WITH
INCREASINGLY ANTICYCLONIC FLOW BRINGING DRY CONDITIONS EVERYWHERE BY
MIDDAY. THERMAL TROUGH WILL BE SHIFTING EAST BY THE AFTERNOON BUT
850MB TEMPS STILL EXPECTED TO BE AROUND -8C DURING PEAK HEATING.
MIXING THIS TO THE SURFACE ONLY GIVES HIGHS IN THE LOW 40S. WILL
LIKELY BE ENOUGH RESIDUAL BOUNDARY LAYER MOISTURE TO SUPPORT SOME
AFTERNOON STRATOCU BUT EXPECT A FAIR AMOUNT OF INSOLATION TO ADD A
DEGREE OR TWO TO THAT. GIVEN YESTERDAYS EXTREME WARM BIAS IN MOS
GUIDANCE...WILL NUDGE THE FORECAST TOWARD COOLER RAW TEMPS. HESITANT
TO DEVIATE LARGELY THOUGH. THIS IS AN ANOMALOUSLY COLD AIRMASS BUT
THERMAL PROFILES WILL BE RECOVERING BY THE AFTERNOON AND DECREASING
CLOUDS SHOULD ALLOW HIGHS TO CLIMB A BIT WARMER THAN
YESTERDAY...GENERALLY LOW TO MID 40S. DIFFICULT MIN TEMP FORECAST
TONIGHT. SURFACE ANTICYCLONE WILL BE OVERHEAD DURING THE EVENING
HOURS BUT MODELS SUGGEST LIGHT SOUTHEAST WINDS DEVELOPING BY EARLY
SUNDAY MORNING ALONG WITH PERHAPS SOME INCREASING MID/UPPER LEVEL
CLOUDS. CURRENT TIMING INDICATES THESE CONDITIONS WILL BE TOO LATE
TO PREVENT SUBSTANTIAL RADIATIVE LOSSES THOUGH AND HAVE THEREFORE
PUSHED TEMPS DOWN A BIT. EXPECT GENERALLY MID TO UPPER 20S BUT A FEW
ISOLATED LOWER 20S ARE POSSIBLE ACROSS THE NORTH.
&&
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 352 AM EDT SAT APR 20 2013
MODELS SUGGEST PERSISTENT PATTERN WITH A CONTINUATION OF A SERIES OF
SHRTWVS DIGGING SE FROM WRN CANADA INTO THE PLAINS AND THEN LIFTING
OUT TO THE NE ACROSS THE GRTLKS RESULTING IN PERIODIC BOUTS OF
INCLEMENT WX WITH TEMPS GENERALLY AOB NORMAL.
HIGH PRESSURE OVER THE NRN PLAINS THIS MORNING IS EXPECTED TO MOVE
TO THE ERN GRTLKS AND NEW ENGLAND BY SUNDAY AND THEN SLOWLY EAST
INTO THE WRN ATLANTIC MONDAY AS NEXT SHRTWV DIGGING INTO THE PLAINS
AMPLIFIES THE FLOW ALOFT. THIS SHOULD RESULT IN FAIR WX WITH A
WARMING TREND SUNDAY-MONDAY. ANOTHER STRENGTHENING LOW PRESSURE
SYSTEM IS EXPECTED TO LIFT NE FROM THE SRN PLAINS MONDAY ACROSS THE
WRN GRTLKS TUE-TUE NGT RESULTING IN A PERIOD OF SHOWERS AND PSBLY A
FEW TSTMS IN THIS TIMEFRAME. GENERALLY DRY AND COOLER WX SHOULD
FOLLOW IN THE WAKE OF THIS SYSTEM WED-THU... THOUGH DID MENTION A
SLIGHT CHC OF SHOWERS DURING THE DAYS AS LONGWAVE TROF MOVES SLOWLY
EAST ACROSS THE GRTLKS. DRY WX WITH WARMER TEMPS EXPECTED FRI AS
SWLY FLOW DVLPS ACROSS OUR AREA ONCE AGAIN AHEAD OF NEXT
SHRTWV/CDFNT MOVG INTO THE PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 210 PM EDT SAT APR 20 2013
DIURNAL VFR CU WILL DIMISH THIS EVENING LEAVING MOSTLY CLEAR
SKIES IN PLACE FOR MUCH OF THE NIGHT. HIGH CLOUDINESS SHOULD
INCREASE BY MORNING...LOWERING TO A MID LEVEL CIG SUNDAY MORNING.
NORTHWEST WINDS AROUND 10 KNOTS WILL BECOME LIGHT AND VARIABLE AS
SFC RIDGE AXIS OVERSPREADS THE SOUTHERN GREAT LAKES. SOUTHEAST
WINDS 10 TO 15 KNOTS TO DEVELOP MID TO LATE MORNING SUNDAY AS THE
SFC HIGH MOVES OFF TO THE EAST.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LMZ043-
046.
&&
$$
UPDATE...MARSILI
SHORT TERM...AGD
LONG TERM...JT
AVIATION...MARSILI
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1215 PM EDT SAT APR 20 2013
.UPDATE...
ISSUED AT 1206 PM EDT SAT APR 20 2013
FAIRLY STRONG NEGATIVE VORTICITY ADVECTION ALOFT IN ASSOCIATION
WITH DEPARTING UPPER LEVEL TROUGH WILL AID LARGE SCALE SUBSIDENCE
THIS AFTERNOON. LACK OF CU FORMATION NOTED FROM NORTHEAST ILLINOIS
INTO FAR NORTHWEST INDIANA IN ASSOCIATION WITH THIS INCREASING
SUBSIDENCE SHOULD EVENTUALLY BECOME THE RULE ACROSS THE LOCAL AREA
LATE THIS AFTERNOON. LINGERING LAKE EFFECT CLOUDINESS WILL
DIMINISH OVER THE NEXT FEW HOURS AS LOW LEVEL FLOW ACROSS SOUTHERN
LAKE MICHIGAN BEGINS TO TRANSITION TO MAINLY A DIVERGENT/ONSHORE
TYPE. CU APPEARS TO BE FAIRLY THICK AND OF GOOD COVERAGE ACROSS
PORTIONS OF EASTERN HALF OF CWA...ALTHOUGH GRADUALLY EXPECTING
THIS CU FIELD TO BECOME LESS VERTICALLY DEVELOPED AND THINNER
THROUGH TIME. DESPITE MAINTENANCE OF LOW LEVEL THERMAL
TROUGH...INCREASED INSOLTATION SHOULD SUPPORT HIGHS CLOSE TO THAT
OF GOING FORECAST OR PERHAPS JUST SHORT OF THAT IN SOME INSTANCES.
WITH GOING FORECAST IN GOOD SHAPE...ONLY MADE SOME MARGINAL TWEAKS
TO SKY COVER TO ACCOUNT FOR CURRENT TRENDS...OTHERWISE PREVIOUS
FORECAST KEPT INTACT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM EDT SAT APR 20 2013
SCATTERED SNOW SHOWERS CONTINUE ACROSS THE CWA AT PRESS TIME...AIDED
BY PERSISTENT MOIST CYCLONIC FLOW ASSOCIATED WITH PASSING MIDLEVEL
TROUGH AXIS. HI-RES FORECAST SOUNDINGS ALSO SHOW BOUNDARY LAYER HAS
REMAINED WELL MIXED THROUGH THE OVERNIGHT HOURS...FURTHER SUPPORTING
CONVECTIVE SNOW SHOWERS. QUESTION WILL BE WHETHER OR NOT ACTIVITY
CAN PERSIST BEYOND 12Z. A FEW PREVIOUS RAP MODEL RUNS SUGGESTED
ISOLATED RAIN/SNOW SHOWERS PERSISTING FOR MUCH OF THE MORNING AS ONE
LAST RIBBON OF SHEAR VORTICITY ROTATES THROUGH THE AREA.
HOWEVER...MIDLEVEL HEIGHTS WILL BE CLIMBING QUICKLY BY LATER THIS
MORNING AND NAM BUFR DATA SHOWS LOWER TROPOSPHERIC DRY AIR
INCREASING AS WELL AS A STRENGTHENING SUBSIDENCE INVERSION.
THEREFORE EXPECT LITTLE MORE THAN ISOLATED FLURRIES AFTER 12Z WITH
INCREASINGLY ANTICYCLONIC FLOW BRINGING DRY CONDITIONS EVERYWHERE BY
MIDDAY. THERMAL TROUGH WILL BE SHIFTING EAST BY THE AFTERNOON BUT
850MB TEMPS STILL EXPECTED TO BE AROUND -8C DURING PEAK HEATING.
MIXING THIS TO THE SURFACE ONLY GIVES HIGHS IN THE LOW 40S. WILL
LIKELY BE ENOUGH RESIDUAL BOUNDARY LAYER MOISTURE TO SUPPORT SOME
AFTERNOON STRATOCU BUT EXPECT A FAIR AMOUNT OF INSOLATION TO ADD A
DEGREE OR TWO TO THAT. GIVEN YESTERDAYS EXTREME WARM BIAS IN MOS
GUIDANCE...WILL NUDGE THE FORECAST TOWARD COOLER RAW TEMPS. HESITANT
TO DEVIATE LARGELY THOUGH. THIS IS AN ANOMALOUSLY COLD AIRMASS BUT
THERMAL PROFILES WILL BE RECOVERING BY THE AFTERNOON AND DECREASING
CLOUDS SHOULD ALLOW HIGHS TO CLIMB A BIT WARMER THAN
YESTERDAY...GENERALLY LOW TO MID 40S. DIFFICULT MIN TEMP FORECAST
TONIGHT. SURFACE ANTICYCLONE WILL BE OVERHEAD DURING THE EVENING
HOURS BUT MODELS SUGGEST LIGHT SOUTHEAST WINDS DEVELOPING BY EARLY
SUNDAY MORNING ALONG WITH PERHAPS SOME INCREASING MID/UPPER LEVEL
CLOUDS. CURRENT TIMING INDICATES THESE CONDITIONS WILL BE TOO LATE
TO PREVENT SUBSTANTIAL RADIATIVE LOSSES THOUGH AND HAVE THEREFORE
PUSHED TEMPS DOWN A BIT. EXPECT GENERALLY MID TO UPPER 20S BUT A FEW
ISOLATED LOWER 20S ARE POSSIBLE ACROSS THE NORTH.
&&
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 352 AM EDT SAT APR 20 2013
MODELS SUGGEST PERSISTENT PATTERN WITH A CONTINUATION OF A SERIES OF
SHRTWVS DIGGING SE FROM WRN CANADA INTO THE PLAINS AND THEN LIFTING
OUT TO THE NE ACROSS THE GRTLKS RESULTING IN PERIODIC BOUTS OF
INCLEMENT WX WITH TEMPS GENERALLY AOB NORMAL.
HIGH PRESSURE OVER THE NRN PLAINS THIS MORNING IS EXPECTED TO MOVE
TO THE ERN GRTLKS AND NEW ENGLAND BY SUNDAY AND THEN SLOWLY EAST
INTO THE WRN ATLANTIC MONDAY AS NEXT SHRTWV DIGGING INTO THE PLAINS
AMPLIFIES THE FLOW ALOFT. THIS SHOULD RESULT IN FAIR WX WITH A
WARMING TREND SUNDAY-MONDAY. ANOTHER STRENGTHENING LOW PRESSURE
SYSTEM IS EXPECTED TO LIFT NE FROM THE SRN PLAINS MONDAY ACROSS THE
WRN GRTLKS TUE-TUE NGT RESULTING IN A PERIOD OF SHOWERS AND PSBLY A
FEW TSTMS IN THIS TIMEFRAME. GENERALLY DRY AND COOLER WX SHOULD
FOLLOW IN THE WAKE OF THIS SYSTEM WED-THU... THOUGH DID MENTION A
SLIGHT CHC OF SHOWERS DURING THE DAYS AS LONGWAVE TROF MOVES SLOWLY
EAST ACROSS THE GRTLKS. DRY WX WITH WARMER TEMPS EXPECTED FRI AS
SWLY FLOW DVLPS ACROSS OUR AREA ONCE AGAIN AHEAD OF NEXT
SHRTWV/CDFNT MOVG INTO THE PLAINS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 557 AM EDT SAT APR 20 2013
SNOW SHOWERS ARE GRADUALLY TAPERING OFF AS MIDLEVEL TROUGH AXIS
LIFTS NORTHEAST AND SUBSIDENCE BUILDS ACROSS THE REGION. A FEW
BRIEF PERIODS OF MVFR CONDITIONS REMAIN POSSIBLE OVER THE NEXT FEW
HOURS THOUGH. STRATOCU WILL GRADUALLY CLEAR OUT OVER THE COURSE
OF THE DAY AS DRIER AIR ADVECTS INTO THE REGION. DEEP MIXING
HEIGHTS WILL KEEP CEILINGS WELL INTO VFR CATEGORY REGARDLESS.
WEAKENING GRADIENT WILL ALSO BRING DECREASING WINDS THROUGH THE
TAF PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LMZ043-
046.
&&
$$
UPDATE...MARSILI
SHORT TERM...AGD
LONG TERM...JT
AVIATION...AGD
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
558 AM EDT SAT APR 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM EDT SAT APR 20 2013
SCATTERED SNOW SHOWERS CONTINUE ACROSS THE CWA AT PRESS TIME...AIDED
BY PERSISTENT MOIST CYCLONIC FLOW ASSOCIATED WITH PASSING MIDLEVEL
TROUGH AXIS. HI-RES FORECAST SOUNDINGS ALSO SHOW BOUNDARY LAYER HAS
REMAINED WELL MIXED THROUGH THE OVERNIGHT HOURS...FURTHER SUPPORTING
CONVECTIVE SNOW SHOWERS. QUESTION WILL BE WHETHER OR NOT ACTIVITY
CAN PERSIST BEYOND 12Z. A FEW PREVIOUS RAP MODEL RUNS SUGGESTED
ISOLATED RAIN/SNOW SHOWERS PERSISTING FOR MUCH OF THE MORNING AS ONE
LAST RIBBON OF SHEAR VORTICITY ROTATES THROUGH THE AREA.
HOWEVER...MIDLEVEL HEIGHTS WILL BE CLIMBING QUICKLY BY LATER THIS
MORNING AND NAM BUFR DATA SHOWS LOWER TROPOSPHERIC DRY AIR
INCREASING AS WELL AS A STRENGTHENING SUBSIDENCE INVERSION.
THEREFORE EXPECT LITTLE MORE THAN ISOLATED FLURRIES AFTER 12Z WITH
INCREASINGLY ANTICYCLONIC FLOW BRINGING DRY CONDITIONS EVERYWHERE BY
MIDDAY. THERMAL TROUGH WILL BE SHIFTING EAST BY THE AFTERNOON BUT
850MB TEMPS STILL EXPECTED TO BE AROUND -8C DURING PEAK HEATING.
MIXING THIS TO THE SURFACE ONLY GIVES HIGHS IN THE LOW 40S. WILL
LIKELY BE ENOUGH RESIDUAL BOUNDARY LAYER MOISTURE TO SUPPORT SOME
AFTERNOON STRATOCU BUT EXPECT A FAIR AMOUNT OF INSOLATION TO ADD A
DEGREE OR TWO TO THAT. GIVEN YESTERDAYS EXTREME WARM BIAS IN MOS
GUIDANCE...WILL NUDGE THE FORECAST TOWARD COOLER RAW TEMPS. HESITANT
TO DEVIATE LARGELY THOUGH. THIS IS AN ANOMALOUSLY COLD AIRMASS BUT
THERMAL PROFILES WILL BE RECOVERING BY THE AFTERNOON AND DECREASING
CLOUDS SHOULD ALLOW HIGHS TO CLIMB A BIT WARMER THAN
YESTERDAY...GENERALLY LOW TO MID 40S. DIFFICULT MIN TEMP FORECAST
TONIGHT. SURFACE ANTICYCLONE WILL BE OVERHEAD DURING THE EVENING
HOURS BUT MODELS SUGGEST LIGHT SOUTHEAST WINDS DEVELOPING BY EARLY
SUNDAY MORNING ALONG WITH PERHAPS SOME INCREASING MID/UPPER LEVEL
CLOUDS. CURRENT TIMING INDICATES THESE CONDITIONS WILL BE TOO LATE
TO PREVENT SUBSTANTIAL RADIATIVE LOSSES THOUGH AND HAVE THEREFORE
PUSHED TEMPS DOWN A BIT. EXPECT GENERALLY MID TO UPPER 20S BUT A FEW
ISOLATED LOWER 20S ARE POSSIBLE ACROSS THE NORTH.
&&
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 352 AM EDT SAT APR 20 2013
MODELS SUGGEST PERSISTENT PATTERN WITH A CONTINUATION OF A SERIES OF
SHRTWVS DIGGING SE FROM WRN CANADA INTO THE PLAINS AND THEN LIFTING
OUT TO THE NE ACROSS THE GRTLKS RESULTING IN PERIODIC BOUTS OF
INCLEMENT WX WITH TEMPS GENERALLY AOB NORMAL.
HIGH PRESSURE OVER THE NRN PLAINS THIS MORNING IS EXPECTED TO MOVE
TO THE ERN GRTLKS AND NEW ENGLAND BY SUNDAY AND THEN SLOWLY EAST
INTO THE WRN ATLANTIC MONDAY AS NEXT SHRTWV DIGGING INTO THE PLAINS
AMPLIFIES THE FLOW ALOFT. THIS SHOULD RESULT IN FAIR WX WITH A
WARMING TREND SUNDAY-MONDAY. ANOTHER STRENGTHENING LOW PRESSURE
SYSTEM IS EXPECTED TO LIFT NE FROM THE SRN PLAINS MONDAY ACROSS THE
WRN GRTLKS TUE-TUE NGT RESULTING IN A PERIOD OF SHOWERS AND PSBLY A
FEW TSTMS IN THIS TIMEFRAME. GENERALLY DRY AND COOLER WX SHOULD
FOLLOW IN THE WAKE OF THIS SYSTEM WED-THU... THOUGH DID MENTION A
SLIGHT CHC OF SHOWERS DURING THE DAYS AS LONGWAVE TROF MOVES SLOWLY
EAST ACROSS THE GRTLKS. DRY WX WITH WARMER TEMPS EXPECTED FRI AS
SWLY FLOW DVLPS ACROSS OUR AREA ONCE AGAIN AHEAD OF NEXT
SHRTWV/CDFNT MOVG INTO THE PLAINS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 557 AM EDT SAT APR 20 2013
SNOW SHOWERS ARE GRADUALLY TAPERING OFF AS MIDLEVEL TROUGH AXIS
LIFTS NORTHEAST AND SUBSIDENCE BUILDS ACROSS THE REGION. A FEW
BRIEF PERIODS OF MVFR CONDITIONS REMAIN POSSIBLE OVER THE NEXT FEW
HOURS THOUGH. STRATOCU WILL GRADUALLY CLEAR OUT OVER THE COURSE
OF THE DAY AS DRIER AIR ADVECTS INTO THE REGION. DEEP MIXING
HEIGHTS WILL KEEP CEILINGS WELL INTO VFR CATEGORY REGARDLESS.
WEAKENING GRADIENT WILL ALSO BRING DECREASING WINDS THROUGH THE
TAF PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LMZ043-
046.
&&
$$
SHORT TERM...AGD
LONG TERM...JT
AVIATION...AGD
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
353 AM EDT SAT APR 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM EDT SAT APR 20 2013
SCATTERED SNOW SHOWERS CONTINUE ACROSS THE CWA AT PRESS TIME...AIDED
BY PERSISTENT MOIST CYCLONIC FLOW ASSOCIATED WITH PASSING MIDLEVEL
TROUGH AXIS. HI-RES FORECAST SOUNDINGS ALSO SHOW BOUNDARY LAYER HAS
REMAINED WELL MIXED THROUGH THE OVERNIGHT HOURS...FURTHER SUPPORTING
CONVECTIVE SNOW SHOWERS. QUESTION WILL BE WHETHER OR NOT ACTIVITY
CAN PERSIST BEYOND 12Z. A FEW PREVIOUS RAP MODEL RUNS SUGGESTED
ISOLATED RAIN/SNOW SHOWERS PERSISTING FOR MUCH OF THE MORNING AS ONE
LAST RIBBON OF SHEAR VORTICITY ROTATES THROUGH THE AREA.
HOWEVER...MIDLEVEL HEIGHTS WILL BE CLIMBING QUICKLY BY LATER THIS
MORNING AND NAM BUFR DATA SHOWS LOWER TROPOSPHERIC DRY AIR
INCREASING AS WELL AS A STRENGTHENING SUBSIDENCE INVERSION.
THEREFORE EXPECT LITTLE MORE THAN ISOLATED FLURRIES AFTER 12Z WITH
INCREASINGLY ANTICYCLONIC FLOW BRINGING DRY CONDITIONS EVERYWHERE BY
MIDDAY. THERMAL TROUGH WILL BE SHIFTING EAST BY THE AFTERNOON BUT
850MB TEMPS STILL EXPECTED TO BE AROUND -8C DURING PEAK HEATING.
MIXING THIS TO THE SURFACE ONLY GIVES HIGHS IN THE LOW 40S. WILL
LIKELY BE ENOUGH RESIDUAL BOUNDARY LAYER MOISTURE TO SUPPORT SOME
AFTERNOON STRATOCU BUT EXPECT A FAIR AMOUNT OF INSOLATION TO ADD A
DEGREE OR TWO TO THAT. GIVEN YESTERDAYS EXTREME WARM BIAS IN MOS
GUIDANCE...WILL NUDGE THE FORECAST TOWARD COOLER RAW TEMPS. HESITANT
TO DEVIATE LARGELY THOUGH. THIS IS AN ANOMALOUSLY COLD AIRMASS BUT
THERMAL PROFILES WILL BE RECOVERING BY THE AFTERNOON AND DECREASING
CLOUDS SHOULD ALLOW HIGHS TO CLIMB A BIT WARMER THAN
YESTERDAY...GENERALLY LOW TO MID 40S. DIFFICULT MIN TEMP FORECAST
TONIGHT. SURFACE ANTICYCLONE WILL BE OVERHEAD DURING THE EVENING
HOURS BUT MODELS SUGGEST LIGHT SOUTHEAST WINDS DEVELOPING BY EARLY
SUNDAY MORNING ALONG WITH PERHAPS SOME INCREASING MID/UPPER LEVEL
CLOUDS. CURRENT TIMING INDICATES THESE CONDITIONS WILL BE TOO LATE
TO PREVENT SUBSTANTIAL RADIATIVE LOSSES THOUGH AND HAVE THEREFORE
PUSHED TEMPS DOWN A BIT. EXPECT GENERALLY MID TO UPPER 20S BUT A FEW
ISOLATED LOWER 20S ARE POSSIBLE ACROSS THE NORTH.
&&
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 352 AM EDT SAT APR 20 2013
MODELS SUGGEST PERSISTENT PATTERN WITH A CONTINUATION OF A SERIES OF
SHRTWVS DIGGING SE FROM WRN CANADA INTO THE PLAINS AND THEN LIFTING
OUT TO THE NE ACROSS THE GRTLKS RESULTING IN PERIODIC BOUTS OF
INCLEMENT WX WITH TEMPS GENERALLY AOB NORMAL.
HIGH PRESSURE OVER THE NRN PLAINS THIS MORNING IS EXPECTED TO MOVE
TO THE ERN GRTLKS AND NEW ENGLAND BY SUNDAY AND THEN SLOWLY EAST
INTO THE WRN ATLANTIC MONDAY AS NEXT SHRTWV DIGGING INTO THE PLAINS
AMPLIFIES THE FLOW ALOFT. THIS SHOULD RESULT IN FAIR WX WITH A
WARMING TREND SUNDAY-MONDAY. ANOTHER STRENGTHENING LOW PRESSURE
SYSTEM IS EXPECTED TO LIFT NE FROM THE SRN PLAINS MONDAY ACROSS THE
WRN GRTLKS TUE-TUE NGT RESULTING IN A PERIOD OF SHOWERS AND PSBLY A
FEW TSTMS IN THIS TIMEFRAME. GENERALLY DRY AND COOLER WX SHOULD
FOLLOW IN THE WAKE OF THIS SYSTEM WED-THU... THOUGH DID MENTION A
SLIGHT CHC OF SHOWERS DURING THE DAYS AS LONGWAVE TROF MOVES SLOWLY
EAST ACROSS THE GRTLKS. DRY WX WITH WARMER TEMPS EXPECTED FRI AS
SWLY FLOW DVLPS ACROSS OUR AREA ONCE AGAIN AHEAD OF NEXT
SHRTWV/CDFNT MOVG INTO THE PLAINS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 125 AM EDT SAT APR 20 2013
LOW LEVEL CYCLONIC FLOW AND WELL MIXED BOUNDARY LAYER/STEEP LOW
LEVEL LAPSE RATES ARE SUPPORTING SCATTERED SNOW SHOWERS ACROSS THE
AREA IN THE WAKE OF DEPARTING LOW PRESSURE SYSTEM. COVERAGE IS
TOO LOW TO INCLUDE IN THE TAFS AT THIS TIME BUT BRIEF PERIODS OF
MVFR CONDITIONS ARE POSSIBLE THROUGH 12Z. DRY AIR AND SUBSIDENCE
WILL INCREASE BY LATER THIS MORNING AS HIGH PRESSURE RETURNS TO
THE REGION. THIS WILL RESULT IN VFR CONDITIONS THROUGH THE END OF
THE TAF PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LMZ043-
046.
&&
$$
SHORT TERM...AGD
LONG TERM...JT
AVIATION...AGD
AREA FORECAST DISCUSSION
NWS GAYLORD MI
120 PM EDT SAT APR 20 2013
.SYNOPSIS...
ISSUED AT 1058 AM EDT SAT APR 20 2013
LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO IMPACT NORTHERN MICHIGAN
THROUGH THE EARLY AFTERNOON HOURS...TARGETING THE TYPICAL SNOWBELT
REGIONS OF EASTERN UPPER AND NORTHWEST LOWER MICHIGAN FOR THE MOST
PERSISTENT AND HEAVIEST SNOW SHOWERS. HIGH PRESSURE WILL BEGIN TO
SETTLE INTO THE GREAT LAKES REGION THIS AFTERNOON...BRINGING QUIET
AND SEASONABLY CHILLY WEATHER TO NORTHERN MICHIGAN THROUGH THE REST
OF THE WEEKEND. THE NEXT CHANCE OF RAIN ARRIVES FOR THE BEGINNING OF
THE WORK WEEK AS SEVERAL WAVES OF LOW PRESSURE PUSH ACROSS THE
REGION.
&&
.UPDATE...
ISSUED AT 1246 PM EDT SAT APR 20 2013
DIURNAL "HEATING" PROCESSES DOING ITS PART IN CREATING A MORE
CELLULAR LOOK TO THE SNOW ON LATEST RADAR. THE PREVIOUS DOMINANT
BAND IS STILL VISIBLE...WITH IT`S EXTENSION REACHING BACK TOWARD
BEAVER ISLAND...BUT ALL OF THE BETTER SNOWS HAVE INDEED DWINDLED
AND BECOME BRIEF. MOST OF THE TIME...FLURRIES CAN BE EXPECTED. NO
SIGNIFICANT CHANGES THIS UPDATE. DID EXTEND SEEING FLURRIES FOR AN
HOUR OR SO INTO THIS AFTERNOON...EVEN FURTHER INLAND AWAY FROM THE
LAKES.
UPDATE ISSUED AT 1052 AM EDT SAT APR 20 2013
DOMINANT BAND OF MODERATE SNOWFALL CONTINUES TO DRIFT NE INTO
OTSEGO...CHARLEVOIX AND NRN CRAWFORD COUNTIES. ALTHOUGH THE
SNOWFALL IS RATHER IMPRESSIVE...ESPECIALLY FOR MID-LATE
APRIL...THE TIME OF YEAR/SUN ANGLE IS NOT ALLOWING SNOW TO
ACCUMULATE MUCH ANYMORE. WE DID HAVE REPORTS OF 1-2 INCHES OF SNOW
OVERNIGHT...AND THESE AMOUNTS WILL NOT BE MET TODAY. THIS IS ALSO
SUPPORTED BY AN EXPECTED TRANSITION TO MORE CELLULAR SHOWERS WITH
INCREASED LOW LEVEL LAPSE RATES...A LOSS OF CYCLONIC CONVERGENCE
AND DRY AIR ENTRAINMENT FROM INVADING HIGH PRESSURE UPSTREAM. WILL
HAVE SOME PEEKS OF SUN AT TIMES...BUT SKIES ARE EXPECTED TO CLEAR
MORE SO LATER THIS AFTERNOON...AS THE BETTER DRY AIR UPSTREAM
FILLS IN BEHIND FINAL SFC TROUGH FROM NRN WISCONSIN THROUGH
EASTERN LAKE SUPERIOR.
WILL ALLOW WINTER HEADLINES TO EXPIRE...WITH IMPACTS FROM
CONTINUED SNOW TO BE MINIMAL. ROADS WILL JUST BE WET FOR MOST ALL
AREAS WITHIN THE ADVISORY.
UPDATE ISSUED AT 717 AM EDT SAT APR 20 2013
MULTI-BAND LAKE EFFECT SNOW SHOWERS HAVE FULLY DEVELOPED ACROSS
OUR CWA...WITH THE DOMINANT BAND EXTENDING FROM NEAR ALDEN TO
KALKASKA. HEAVIER SNOW SHOWERS REMAIN EMBEDDED WITHIN THIS
DOMINANT BAND...WITH SNOWFALL RATES OF AROUND AN INCH AN HOUR.
WILL MAINTAIN THE LAKE SNOW ADVISORY FOR THE SNOWBELT REGION OF NW
AND N CENTRAL LWR MICHIGAN THRU LATE MORNING...AT WHICH TIME SNOW
SHOWERS SHOULD BEGIN TO BREAK DOWN AS HIGH PRESSURE AND DRIER AIR
BEGIN TO BUILD INTO THE WRN GREAT LAKES.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 300 AM EDT SAT APR 20 2013
WELL...THIS JUST ISN`T RIGHT FOR MID APRIL...COLD AND GUSTY
NORTHWEST WINDS...WITH NUMEROUS GROUND WHITENING LAKE INDUCED SNOW
SHOWERS TARGETING THE TRADITIONAL SNOW BELTS. CULPRIT BEHIND THIS
NONSENSE IS ANOMALOUSLY DEEP TROUGH EXTENDING FROM THE MID
MISSISSIPPI VALLEY UP THROUGH JAMES BAY. ATTENDANT BEHEMOTH SURFACE
LOW NOW WELL TO OUR NORTHEAST UP ACROSS CENTRAL QUEBEC...WITH
SURFACE TROUGH AXIS EXTENDING BACK SOUTHWEST INTO OUR AREA. COMBO OF
DEEP MOISTURE AND MORE THAN PLENTIFUL OVER-WATER INSTABILITY (H8
TEMPERATURES DOWN AROUND -14/-15C PER RAP ANALYSIS) HELPING DRIVE
THOSE LAKE SNOWS. FORECAST CONCERNS THROUGH THE SHORT TERM REAL CENTERED
WITHIN THE FIRST HALF OF TODAY...CENTERING ON LINGERING LAKE INDUCED
SNOW POTENTIAL AND POSSIBLE ADDITIONAL ACCUMULATIONS.
RESPECTABLE LAKE SNOW PARAMETERS REMAIN IN PLACE EARLY ON THIS
MORNING...WITH MORE THAN SUFFICIENT DELTA T/S AUGMENTED BY REMNANT
DEEPER MOISTURE AND GOOD INVERSION LEVELS UP THROUGH H7 LEVELS. NNW
(LAKE SUPERIOR) TO NW (NORTHERN LAKE MICHIGAN) FLOW REGIME WILL
LOCKED IN BY SUNRISE...TARGETING THE NORTHWEST LOWER SNOWBELTS FOR
THE MOST PERSISTENT AND HEAVIEST ACTIVITY. GIVEN FLOW...WOULD EXPECT
BETTER LAKE SUPERIOR ACTIVITY TO REMAIN JUST WEST OF CHIPPEWA
COUNTY. DECISIVE DOWNTURN IN LAKE SNOW PARAMETERS EXPECTED AFTER
ABOUT 15Z...WITH STEADY LOSS OF SYNOPTIC MOISTURE SUPPORT AND
LOWERING INVERSION LEVELS. DIURNAL DISRUPTION WILL ONLY HELP THE
CAUSE..AS WILL DEEPENING OF SURFACE BASED DRY WEDGE. WOULD EXPECT
SCATTERED LATE MORNING ACTIVITY TO COMPLETELY END BY EARLY AFTERNOON
(YUP...SAID THAT BEFORE). UPSHOT TO ALL THE ABOVE...THINKING PERHAPS
ANOTHER INCH OR SO IN NORTHWEST LOWER SNOWBELTS THIS MORNING...LEAVING
THE INHERITED LAKE SNOW ADVISORY THROUGH ITS DURATION ENDING AT 15Z.
LESS ACCUMULATION EXPECTED ELSEWHERE. DRYING REMAINS AGGRESSIVE
THROUGH THE AFTERNOON...AND STILL EXPECT SKIES TO TREND PARTLY SUNNY
TO SUNNY ALL AREAS. UNFORTUNATELY...EVEN MID APRIL SUN WILL DO
LITTLE TO HELP THE TEMPERATURE CAUSE...WITH READINGS A SOLID 15 TO
20 DEGREES BELOW NORMAL. GUSTY NORTHWEST WINDS WILL SUBSIDE THROUGH
THE DAY...BUT NOT BEFORE MAKING IT FEEL DOWNRIGHT COLD THROUGH THE
EARLY AFTERNOON.
MUCH QUIETER HEADING INTO TONIGHT AS DRYING BECOMES COMPLETE AND
HIGH PRESSURE BUILDS DIRECTLY OVERHEAD. MOSTLY CLEAR SKIES...WITH
PERHAPS A TOUCH OF HIGH CLOUDS LATE. RADIATION COOLING TRIFECTA...
WITH QUICK LOSS OF WINDS...CLEAR SKIES..AND DRY LOW LEVELS. GUIDANCE
CONTINUES TO TREND COLDER...NOW SHOWING THE TRADITIONAL ICE BOX
LOCALES FLIRTING WITH THE UPPER SINGLE DIGITS. WILL NOT GO QUITE
THIS AGGRESSIVE...USING LOWER TEENS FOR THE COLDER LOCATIONS. THESE
NUMBERS FLIRT WITH RECORD LOWS FOR THE DAY...WITHIN A FEW DEGREES AT
SEVERAL SITES. COULD EASILY SEE A RECORD TO TWO BROKEN BY SUNRISE
SUNDAY.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 300 AM EDT SAT APR 20 2013
.SUNDAY AND MONDAY...STRONG SURFACE HIGH PRESSURE CENTER SHIFTS EAST
OF MICHIGAN BY 12Z SUNDAY. AFTER A FRIGID START TO THE DAY...WITH
EARLY MORNING LOWS IN THE TEENS (WHICH IS ROUGHLY 20 DEGREES BELOW
NORMAL)...TEMPS WILL REBOUND NICELY AS SOUTHERLY FLOW KICKS IN ON
THE BACK SIDE OF THE HIGH CENTER. CLOUDS WILL INCREASE/THICKEN/LOWER
FROM WEST TO EAST AS MAINLY MID/UPPER LEVEL MOISTURE BEGINS TO
ADVECT INTO THE WRN GREAT LAKES IN ADVANCE OF A COLD FRONT DRIVING
EAST THRU MINNESOTA. STILL APPEARS ANY PRECIP CHANCES WILL HOLD OFF
UNTIL SUNDAY NIGHT...AND WILL BE CONFINED TO MAINLY ERN UPR
MICHIGAN. ONCE THE COLD FRONT REACHES WRN UPR MICHIGAN AND
WISCONSIN...UPPER LEVEL FLOW BECOMES NEARLY PARALLEL WITH THE FRONT
ITSELF...WHICH WILL SLOW ITS EASTWARD PROGRESS. ALSO...A WAVE
DEVELOPS ALONG THE FRONT...DEEPENING INTO A CLOSED LOW THAT DRIVES
NE THRU THE STRAITS ON TUESDAY (MORE ON THIS BELOW). WITH THE SLOW
EASTWARD PUSH OF THE FRONT AND ASSOCIATED MOISTURE...POPS WILL
GRADUALLY SPREAD FROM ERN UPR MICHIGAN SUNDAY NIGHT INTO THE STRAITS
AND ALONG THE LAKE MICHIGAN SHORELINE TO LEELANAU COUNTY ON
MONDAY...AND THEN FINALLY MAKE SOME HEADWAY INTO NRN LWR MICHIGAN
WEST OF A LINE FROM ROGERS CITY TO HTL LATE MONDAY NIGHT AS THAT
WAVE (MENTIONED ABOVE) BEGINS TO LIFT INTO OUR CWA. AGAIN...TEMPS
WILL RECOVER NICELY DURING THE FIRST PART OF NEXT WEEK THANKS TO WAA
AHEAD OF THE SLOW COLD FRONT. HIGHS ON SUNDAY WILL WARM INTO THE MID
40S TO LOWER 50S...BUT WILL COOL BACK INTO THE 30S AT NIGHT.
HOWEVER...PRECIP SUNDAY NIGHT IN ERN UPR MICHIGAN SHOULD BE ALL
LIQUID PER NAM BUFR SOUNDINGS SHOWING A SURFACE-BASED ABOVE FREEZING
LAYER THRU 850 MB. WAA FURTHER STRENGTHENS ON MONDAY...WITH TEMPS
CLIMBING TO NEAR 50 IN ERN UPR MICHIGAN AND WELL INTO THE 50S TO
NEAR 60 ACROSS NRN LWR MICHIGAN. COLD FRONT REMAINS WEST OF OUR CWA
MONDAY NIGHT. TEMPS WILL COOLING MAINLY BACK INTO THE 40S MONDAY
NIGHT...KEEPING ANY PRECIP ALL LIQUID.
TUESDAY THRU FRIDAY...AS MENTIONED ABOVE...FIRST WAVE TRACKS ALONG
THE COLD FRONT AND THRU THE STRAITS TUESDAY MORNING. THIS FEATURE
COMBINED WITH DEEP MOISTURE WILL PRODUCE RAIN SHOWERS ACROSS MUCH OF
OUR CWA ON TUESDAY. SECOND WAVE DEVELOPS ALONG THE FRONT AND TRACKS
THRU SRN LWR MICHIGAN TUESDAY NIGHT...SPREADING ANOTHER AREA OF RAIN
SHOWERS THRU MOST OF MICHIGAN. WITH AREA RIVERS ALREADY RUNNING HIGH
FROM RECENT RAIN AND SNOWMELT...WILL NEED TO KEEP AN EYE ON THE
POTENTIAL FOR HEAVY RAINFALL ESPECIALLY WITH THIS SECOND WAVE AS IT
BEGINS TO TAP INTO GULF MOISTURE TUESDAY NIGHT. FOR NOW...WILL STICK
WITH LIKELY POPS FOR TUESDAY AND TUESDAY NIGHT ACROSS MOST OF OUR
CWA. PRECIP CHANCES DIMINISH ON WEDNESDAY AS THE FRONT EXITS TO THE
EAST COAST AND SURFACE RIDGING BUILDS INTO MICHIGAN. A WEAK
MOISTURE-STARVED NRN STREAM WAVE QUICKLY SWINGS THRU MICHIGAN
THURSDAY...PRODUCING A QUICK CHANCE OF LIGHT RAIN. DEEPER MOISTURE
WILL BEGIN TO ADVECT INTO THE WRN GREAT LAKES ON FRIDAY ONCE
SOUTHERLY RETURN FLOW KICKS IN ON THE BACK SIDE OF HIGH PRESSURE.
FIRST LOOK AT NEXT WEEKEND LOOKS UNSETTLED WITH NEAR NORMAL TEMPS IN
THE 50S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1246 PM EDT SAT APR 20 2013
ANY LINGERING LAKE EFFECT SNOW SHOWERS WILL END WITHIN THE FIRST
FEW HOURS OF THE TAF PERIOD...AS HIGH PRESSURE BUILDS BEHIND THE
DEPARTING STORM SYSTEM OVER QUEBEC. VFR CONDITIONS WILL PREVAIL
THROUGHOUT THE ENTIRE TAF PERIOD FOR ALL TAF SITES. SKIES WILL
CLEAR OUT THIS EVENING UNTIL A DECK OF MID-LEVEL CLOUDS OVERTAKE
NORTHERN MICHIGAN TOMORROW MORNING.
&&
.MARINE...
ISSUED AT 120 PM EDT SAT APR 20 2013
WINDS KEEP GUSTING INTO ADVISORY LEVELS..GALES ACROSS PRESQUE ISLE
DUE TO TIGHT GRADIENT AND VERY UNSTABLE CONDITIONS OVER THE GREAT
LAKES. RAPIDLY APPROACHING HIGH PRESSURE WILL ALLOW THESE
HEADLINES TO END BY EVENING. NO WORRIES THROUGH MUCH OF TOMORROW
SUNDAY...HOWEVER NEXT FRONT APPROACHES AND TIGHTENS UP THE
GRADIENT AGAIN. SOUTHERLY WINDS WILL BE BLOWING TO ADVISORY LEVEL
ACROSS MAINLY THE LAKE MICHIGAN NEARSHORE WATERS LATE SUNDAY
THROUGH MONDAY. TIMING OF THIS FRONT IS UNCERTAIN...BUT CHANCES
FOR RAIN ARRIVE PRIMARILY TUESDAY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LHZ345-
346-349.
GALE WARNING UNTIL 5 PM EDT THIS AFTERNOON FOR LHZ347-348.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LMZ323-
341-342-344>346.
LS...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ321-
322.
&&
$$
UPDATE...SD
SYNOPSIS...MR
SHORT TERM...MB
LONG TERM...MR
AVIATION...TL
MARINE...SD
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1252 PM EDT SAT APR 20 2013
.SYNOPSIS...
ISSUED AT 1058 AM EDT SAT APR 20 2013
LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO IMPACT NORTHERN MICHIGAN
THROUGH THE EARLY AFTERNOON HOURS...TARGETING THE TYPICAL SNOWBELT
REGIONS OF EASTERN UPPER AND NORTHWEST LOWER MICHIGAN FOR THE MOST
PERSISTENT AND HEAVIEST SNOW SHOWERS. HIGH PRESSURE WILL BEGIN TO
SETTLE INTO THE GREAT LAKES REGION THIS AFTERNOON...BRINGING QUIET
AND SEASONABLY CHILLY WEATHER TO NORTHERN MICHIGAN THROUGH THE REST
OF THE WEEKEND. THE NEXT CHANCE OF RAIN ARRIVES FOR THE BEGINNING OF
THE WORK WEEK AS SEVERAL WAVES OF LOW PRESSURE PUSH ACROSS THE
REGION.
&&
.UPDATE...
ISSUED AT 1246 PM EDT SAT APR 20 2013
DIURNAL "HEATING" PROCESSES DOING ITS PART IN CREATING A MORE
CELLULAR LOOK TO THE SNOW ON LATEST RADAR. THE PREVIOUS DOMINANT
BAND IS STILL VISIBLE...WITH IT`S EXTENSION REACHING BACK TOWARD
BEAVER ISLAND...BUT ALL OF THE BETTER SNOWS HAVE INDEED DWINDLED
AND BECOME BRIEF. MOST OF THE TIME...FLURRIES CAN BE EXPECTED. NO
SIGNIFICANT CHANGES THIS UPDATE. DID EXTEND SEEING FLURRIES FOR AN
HOUR OR SO INTO THIS AFTERNOON...EVEN FURTHER INLAND AWAY FROM THE
LAKES.
UPDATE ISSUED AT 1052 AM EDT SAT APR 20 2013
DOMINANT BAND OF MODERATE SNOWFALL CONTINUES TO DRIFT NE INTO
OTSEGO...CHARLEVOIX AND NRN CRAWFORD COUNTIES. ALTHOUGH THE
SNOWFALL IS RATHER IMPRESSIVE...ESPECIALLY FOR MID-LATE
APRIL...THE TIME OF YEAR/SUN ANGLE IS NOT ALLOWING SNOW TO
ACCUMULATE MUCH ANYMORE. WE DID HAVE REPORTS OF 1-2 INCHES OF SNOW
OVERNIGHT...AND THESE AMOUNTS WILL NOT BE MET TODAY. THIS IS ALSO
SUPPORTED BY AN EXPECTED TRANSITION TO MORE CELLULAR SHOWERS WITH
INCREASED LOW LEVEL LAPSE RATES...A LOSS OF CYCLONIC CONVERGENCE
AND DRY AIR ENTRAINMENT FROM INVADING HIGH PRESSURE UPSTREAM. WILL
HAVE SOME PEEKS OF SUN AT TIMES...BUT SKIES ARE EXPECTED TO CLEAR
MORE SO LATER THIS AFTERNOON...AS THE BETTER DRY AIR UPSTREAM
FILLS IN BEHIND FINAL SFC TROUGH FROM NRN WISCONSIN THROUGH
EASTERN LAKE SUPERIOR.
WILL ALLOW WINTER HEADLINES TO EXPIRE...WITH IMPACTS FROM
CONTINUED SNOW TO BE MINIMAL. ROADS WILL JUST BE WET FOR MOST ALL
AREAS WITHIN THE ADVISORY.
UPDATE ISSUED AT 717 AM EDT SAT APR 20 2013
MULTI-BAND LAKE EFFECT SNOW SHOWERS HAVE FULLY DEVELOPED ACROSS
OUR CWA...WITH THE DOMINANT BAND EXTENDING FROM NEAR ALDEN TO
KALKASKA. HEAVIER SNOW SHOWERS REMAIN EMBEDDED WITHIN THIS
DOMINANT BAND...WITH SNOWFALL RATES OF AROUND AN INCH AN HOUR.
WILL MAINTAIN THE LAKE SNOW ADVISORY FOR THE SNOWBELT REGION OF NW
AND N CENTRAL LWR MICHIGAN THRU LATE MORNING...AT WHICH TIME SNOW
SHOWERS SHOULD BEGIN TO BREAK DOWN AS HIGH PRESSURE AND DRIER AIR
BEGIN TO BUILD INTO THE WRN GREAT LAKES.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 300 AM EDT SAT APR 20 2013
WELL...THIS JUST ISN`T RIGHT FOR MID APRIL...COLD AND GUSTY
NORTHWEST WINDS...WITH NUMEROUS GROUND WHITENING LAKE INDUCED SNOW
SHOWERS TARGETING THE TRADITIONAL SNOW BELTS. CULPRIT BEHIND THIS
NONSENSE IS ANOMALOUSLY DEEP TROUGH EXTENDING FROM THE MID
MISSISSIPPI VALLEY UP THROUGH JAMES BAY. ATTENDANT BEHEMOTH SURFACE
LOW NOW WELL TO OUR NORTHEAST UP ACROSS CENTRAL QUEBEC...WITH
SURFACE TROUGH AXIS EXTENDING BACK SOUTHWEST INTO OUR AREA. COMBO OF
DEEP MOISTURE AND MORE THAN PLENTIFUL OVER-WATER INSTABILITY (H8
TEMPERATURES DOWN AROUND -14/-15C PER RAP ANALYSIS) HELPING DRIVE
THOSE LAKE SNOWS. FORECAST CONCERNS THROUGH THE SHORT TERM REAL CENTERED
WITHIN THE FIRST HALF OF TODAY...CENTERING ON LINGERING LAKE INDUCED
SNOW POTENTIAL AND POSSIBLE ADDITIONAL ACCUMULATIONS.
RESPECTABLE LAKE SNOW PARAMETERS REMAIN IN PLACE EARLY ON THIS
MORNING...WITH MORE THAN SUFFICIENT DELTA T/S AUGMENTED BY REMNANT
DEEPER MOISTURE AND GOOD INVERSION LEVELS UP THROUGH H7 LEVELS. NNW
(LAKE SUPERIOR) TO NW (NORTHERN LAKE MICHIGAN) FLOW REGIME WILL
LOCKED IN BY SUNRISE...TARGETING THE NORTHWEST LOWER SNOWBELTS FOR
THE MOST PERSISTENT AND HEAVIEST ACTIVITY. GIVEN FLOW...WOULD EXPECT
BETTER LAKE SUPERIOR ACTIVITY TO REMAIN JUST WEST OF CHIPPEWA
COUNTY. DECISIVE DOWNTURN IN LAKE SNOW PARAMETERS EXPECTED AFTER
ABOUT 15Z...WITH STEADY LOSS OF SYNOPTIC MOISTURE SUPPORT AND
LOWERING INVERSION LEVELS. DIURNAL DISRUPTION WILL ONLY HELP THE
CAUSE..AS WILL DEEPENING OF SURFACE BASED DRY WEDGE. WOULD EXPECT
SCATTERED LATE MORNING ACTIVITY TO COMPLETELY END BY EARLY AFTERNOON
(YUP...SAID THAT BEFORE). UPSHOT TO ALL THE ABOVE...THINKING PERHAPS
ANOTHER INCH OR SO IN NORTHWEST LOWER SNOWBELTS THIS MORNING...LEAVING
THE INHERITED LAKE SNOW ADVISORY THROUGH ITS DURATION ENDING AT 15Z.
LESS ACCUMULATION EXPECTED ELSEWHERE. DRYING REMAINS AGGRESSIVE
THROUGH THE AFTERNOON...AND STILL EXPECT SKIES TO TREND PARTLY SUNNY
TO SUNNY ALL AREAS. UNFORTUNATELY...EVEN MID APRIL SUN WILL DO
LITTLE TO HELP THE TEMPERATURE CAUSE...WITH READINGS A SOLID 15 TO
20 DEGREES BELOW NORMAL. GUSTY NORTHWEST WINDS WILL SUBSIDE THROUGH
THE DAY...BUT NOT BEFORE MAKING IT FEEL DOWNRIGHT COLD THROUGH THE
EARLY AFTERNOON.
MUCH QUIETER HEADING INTO TONIGHT AS DRYING BECOMES COMPLETE AND
HIGH PRESSURE BUILDS DIRECTLY OVERHEAD. MOSTLY CLEAR SKIES...WITH
PERHAPS A TOUCH OF HIGH CLOUDS LATE. RADIATION COOLING TRIFECTA...
WITH QUICK LOSS OF WINDS...CLEAR SKIES..AND DRY LOW LEVELS. GUIDANCE
CONTINUES TO TREND COLDER...NOW SHOWING THE TRADITIONAL ICE BOX
LOCALES FLIRTING WITH THE UPPER SINGLE DIGITS. WILL NOT GO QUITE
THIS AGGRESSIVE...USING LOWER TEENS FOR THE COLDER LOCATIONS. THESE
NUMBERS FLIRT WITH RECORD LOWS FOR THE DAY...WITHIN A FEW DEGREES AT
SEVERAL SITES. COULD EASILY SEE A RECORD TO TWO BROKEN BY SUNRISE
SUNDAY.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 300 AM EDT SAT APR 20 2013
.SUNDAY AND MONDAY...STRONG SURFACE HIGH PRESSURE CENTER SHIFTS EAST
OF MICHIGAN BY 12Z SUNDAY. AFTER A FRIGID START TO THE DAY...WITH
EARLY MORNING LOWS IN THE TEENS (WHICH IS ROUGHLY 20 DEGREES BELOW
NORMAL)...TEMPS WILL REBOUND NICELY AS SOUTHERLY FLOW KICKS IN ON
THE BACK SIDE OF THE HIGH CENTER. CLOUDS WILL INCREASE/THICKEN/LOWER
FROM WEST TO EAST AS MAINLY MID/UPPER LEVEL MOISTURE BEGINS TO
ADVECT INTO THE WRN GREAT LAKES IN ADVANCE OF A COLD FRONT DRIVING
EAST THRU MINNESOTA. STILL APPEARS ANY PRECIP CHANCES WILL HOLD OFF
UNTIL SUNDAY NIGHT...AND WILL BE CONFINED TO MAINLY ERN UPR
MICHIGAN. ONCE THE COLD FRONT REACHES WRN UPR MICHIGAN AND
WISCONSIN...UPPER LEVEL FLOW BECOMES NEARLY PARALLEL WITH THE FRONT
ITSELF...WHICH WILL SLOW ITS EASTWARD PROGRESS. ALSO...A WAVE
DEVELOPS ALONG THE FRONT...DEEPENING INTO A CLOSED LOW THAT DRIVES
NE THRU THE STRAITS ON TUESDAY (MORE ON THIS BELOW). WITH THE SLOW
EASTWARD PUSH OF THE FRONT AND ASSOCIATED MOISTURE...POPS WILL
GRADUALLY SPREAD FROM ERN UPR MICHIGAN SUNDAY NIGHT INTO THE STRAITS
AND ALONG THE LAKE MICHIGAN SHORELINE TO LEELANAU COUNTY ON
MONDAY...AND THEN FINALLY MAKE SOME HEADWAY INTO NRN LWR MICHIGAN
WEST OF A LINE FROM ROGERS CITY TO HTL LATE MONDAY NIGHT AS THAT
WAVE (MENTIONED ABOVE) BEGINS TO LIFT INTO OUR CWA. AGAIN...TEMPS
WILL RECOVER NICELY DURING THE FIRST PART OF NEXT WEEK THANKS TO WAA
AHEAD OF THE SLOW COLD FRONT. HIGHS ON SUNDAY WILL WARM INTO THE MID
40S TO LOWER 50S...BUT WILL COOL BACK INTO THE 30S AT NIGHT.
HOWEVER...PRECIP SUNDAY NIGHT IN ERN UPR MICHIGAN SHOULD BE ALL
LIQUID PER NAM BUFR SOUNDINGS SHOWING A SURFACE-BASED ABOVE FREEZING
LAYER THRU 850 MB. WAA FURTHER STRENGTHENS ON MONDAY...WITH TEMPS
CLIMBING TO NEAR 50 IN ERN UPR MICHIGAN AND WELL INTO THE 50S TO
NEAR 60 ACROSS NRN LWR MICHIGAN. COLD FRONT REMAINS WEST OF OUR CWA
MONDAY NIGHT. TEMPS WILL COOLING MAINLY BACK INTO THE 40S MONDAY
NIGHT...KEEPING ANY PRECIP ALL LIQUID.
TUESDAY THRU FRIDAY...AS MENTIONED ABOVE...FIRST WAVE TRACKS ALONG
THE COLD FRONT AND THRU THE STRAITS TUESDAY MORNING. THIS FEATURE
COMBINED WITH DEEP MOISTURE WILL PRODUCE RAIN SHOWERS ACROSS MUCH OF
OUR CWA ON TUESDAY. SECOND WAVE DEVELOPS ALONG THE FRONT AND TRACKS
THRU SRN LWR MICHIGAN TUESDAY NIGHT...SPREADING ANOTHER AREA OF RAIN
SHOWERS THRU MOST OF MICHIGAN. WITH AREA RIVERS ALREADY RUNNING HIGH
FROM RECENT RAIN AND SNOWMELT...WILL NEED TO KEEP AN EYE ON THE
POTENTIAL FOR HEAVY RAINFALL ESPECIALLY WITH THIS SECOND WAVE AS IT
BEGINS TO TAP INTO GULF MOISTURE TUESDAY NIGHT. FOR NOW...WILL STICK
WITH LIKELY POPS FOR TUESDAY AND TUESDAY NIGHT ACROSS MOST OF OUR
CWA. PRECIP CHANCES DIMINISH ON WEDNESDAY AS THE FRONT EXITS TO THE
EAST COAST AND SURFACE RIDGING BUILDS INTO MICHIGAN. A WEAK
MOISTURE-STARVED NRN STREAM WAVE QUICKLY SWINGS THRU MICHIGAN
THURSDAY...PRODUCING A QUICK CHANCE OF LIGHT RAIN. DEEPER MOISTURE
WILL BEGIN TO ADVECT INTO THE WRN GREAT LAKES ON FRIDAY ONCE
SOUTHERLY RETURN FLOW KICKS IN ON THE BACK SIDE OF HIGH PRESSURE.
FIRST LOOK AT NEXT WEEKEND LOOKS UNSETTLED WITH NEAR NORMAL TEMPS IN
THE 50S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1246 PM EDT SAT APR 20 2013
ANY LINGERING LAKE EFFECT SNOW SHOWERS WILL END WITHIN THE FIRST
FEW HOURS OF THE TAF PERIOD...AS HIGH PRESSURE BUILDS BEHIND THE
DEPARTING STORM SYSTEM OVER QUEBEC. VFR CONDITIONS WILL PREVAIL
THROUGHOUT THE ENTIRE TAF PERIOD FOR ALL TAF SITES. SKIES WILL
CLEAR OUT THIS EVENING UNTIL A DECK OF MID-LEVEL CLOUDS OVERTAKE
NORTHERN MICHIGAN TOMORROW MORNING.
&&
.MARINE...
ISSUED AT 1052 AM EDT SAT APR 20 2013
UPDATE...GALES CONTINUE ACROSS PRESQUE ISLE...AND WILL EXTEND THE
GALE WARNING THROUGH 1-2 PM. ALL OTHER AREAS WILL BE IN THE SMALL
CRAFT ADVISORY FOR THE DAY. HEADLINES ARE EXPECTED TO BE LIFTED
MOST ALL AREAS BY EVENING (MAYBE NOT PRESQUE ISLE)...AS A QUICK
TRANSITION TO LIGHTER WINDS ARRIVES WITH HIGH PRESSURE.
SLOW...BUT STEADY...IMPROVEMENT EXPECTED ACROSS ALL WATERS
TODAY AS HIGH PRESSURE BUILDS INTO THE REGION. REMNANT GUSTY
NORTHWEST WINDS AND CHOPPY WAVES WILL REQUIRE SCA/S FOR NEARLY ALL
WATERS...BUT ALL GALE WARNINGS WILL BE ALLOWED TO EXPIRE BY 12Z.
RAPID IMPROVEMENT EXPECTED LATE THIS AFTERNOON AND EVENING AS WINDS
GO LIGHT UNDER OVERHEAD HIGH PRESSURE. GUSTY SOUTHEAST WINDS DEVELOP
SUNDAY...POSSIBLY REQUIRING ADDITIONAL SCA/S FOR SOME NEARSHORE
WATERS.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LHZ345-
346-349.
GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR LHZ347-348.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LMZ323-
341-342-344>346.
LS...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ321-
322.
&&
$$
UPDATE...SD
SYNOPSIS...MR
SHORT TERM...MB
LONG TERM...MR
AVIATION...TL
MARINE...MB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1248 PM EDT SAT APR 20 2013
.SYNOPSIS...
ISSUED AT 1058 AM EDT SAT APR 20 2013
LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO IMPACT NORTHERN MICHIGAN
THROUGH THE EARLY AFTERNOON HOURS...TARGETING THE TYPICAL SNOWBELT
REGIONS OF EASTERN UPPER AND NORTHWEST LOWER MICHIGAN FOR THE MOST
PERSISTENT AND HEAVIEST SNOW SHOWERS. HIGH PRESSURE WILL BEGIN TO
SETTLE INTO THE GREAT LAKES REGION THIS AFTERNOON...BRINGING QUIET
AND SEASONABLY CHILLY WEATHER TO NORTHERN MICHIGAN THROUGH THE REST
OF THE WEEKEND. THE NEXT CHANCE OF RAIN ARRIVES FOR THE BEGINNING OF
THE WORK WEEK AS SEVERAL WAVES OF LOW PRESSURE PUSH ACROSS THE
REGION.
&&
.UPDATE...
ISSUED AT 1052 AM EDT SAT APR 20 2013
DOMINANT BAND OF MODERATE SNOWFALL CONTINUES TO DRIFT NE INTO
OTSEGO...CHARLEVOIX AND NRN CRAWFORD COUNTIES. ALTHOUGH THE
SNOWFALL IS RATHER IMPRESSIVE...ESPECIALLY FOR MID-LATE
APRIL...THE TIME OF YEAR/SUN ANGLE IS NOT ALLOWING SNOW TO
ACCUMULATE MUCH ANYMORE. WE DID HAVE REPORTS OF 1-2 INCHES OF SNOW
OVERNIGHT...AND THESE AMOUNTS WILL NOT BE MET TODAY. THIS IS ALSO
SUPPORTED BY AN EXPECTED TRANSITION TO MORE CELLULAR SHOWERS WITH
INCREASED LOW LEVEL LAPSE RATES...A LOSS OF CYCLONIC CONVERGENCE
AND DRY AIR ENTRAINMENT FROM INVADING HIGH PRESSURE UPSTREAM. WILL
HAVE SOME PEEKS OF SUN AT TIMES...BUT SKIES ARE EXPECTED TO CLEAR
MORE SO LATER THIS AFTERNOON...AS THE BETTER DRY AIR UPSTREAM
FILLS IN BEHIND FINAL SFC TROUGH FROM NRN WISCONSIN THROUGH
EASTERN LAKE SUPERIOR.
WILL ALLOW WINTER HEADLINES TO EXPIRE...WITH IMPACTS FROM
CONTINUED SNOW TO BE MINIMAL. ROADS WILL JUST BE WET FOR MOST ALL
AREAS WITHIN THE ADVISORY.
UPDATE ISSUED AT 717 AM EDT SAT APR 20 2013
MULTI-BAND LAKE EFFECT SNOW SHOWERS HAVE FULLY DEVELOPED ACROSS
OUR CWA...WITH THE DOMINANT BAND EXTENDING FROM NEAR ALDEN TO
KALKASKA. HEAVIER SNOW SHOWERS REMAIN EMBEDDED WITHIN THIS
DOMINANT BAND...WITH SNOWFALL RATES OF AROUND AN INCH AN HOUR.
WILL MAINTAIN THE LAKE SNOW ADVISORY FOR THE SNOWBELT REGION OF NW
AND N CENTRAL LWR MICHIGAN THRU LATE MORNING...AT WHICH TIME SNOW
SHOWERS SHOULD BEGIN TO BREAK DOWN AS HIGH PRESSURE AND DRIER AIR
BEGIN TO BUILD INTO THE WRN GREAT LAKES.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 300 AM EDT SAT APR 20 2013
WELL...THIS JUST ISN`T RIGHT FOR MID APRIL...COLD AND GUSTY
NORTHWEST WINDS...WITH NUMEROUS GROUND WHITENING LAKE INDUCED SNOW
SHOWERS TARGETING THE TRADITIONAL SNOW BELTS. CULPRIT BEHIND THIS
NONSENSE IS ANOMALOUSLY DEEP TROUGH EXTENDING FROM THE MID
MISSISSIPPI VALLEY UP THROUGH JAMES BAY. ATTENDANT BEHEMOTH SURFACE
LOW NOW WELL TO OUR NORTHEAST UP ACROSS CENTRAL QUEBEC...WITH
SURFACE TROUGH AXIS EXTENDING BACK SOUTHWEST INTO OUR AREA. COMBO OF
DEEP MOISTURE AND MORE THAN PLENTIFUL OVER-WATER INSTABILITY (H8
TEMPERATURES DOWN AROUND -14/-15C PER RAP ANALYSIS) HELPING DRIVE
THOSE LAKE SNOWS. FORECAST CONCERNS THROUGH THE SHORT TERM REAL CENTERED
WITHIN THE FIRST HALF OF TODAY...CENTERING ON LINGERING LAKE INDUCED
SNOW POTENTIAL AND POSSIBLE ADDITIONAL ACCUMULATIONS.
RESPECTABLE LAKE SNOW PARAMETERS REMAIN IN PLACE EARLY ON THIS
MORNING...WITH MORE THAN SUFFICIENT DELTA T/S AUGMENTED BY REMNANT
DEEPER MOISTURE AND GOOD INVERSION LEVELS UP THROUGH H7 LEVELS. NNW
(LAKE SUPERIOR) TO NW (NORTHERN LAKE MICHIGAN) FLOW REGIME WILL
LOCKED IN BY SUNRISE...TARGETING THE NORTHWEST LOWER SNOWBELTS FOR
THE MOST PERSISTENT AND HEAVIEST ACTIVITY. GIVEN FLOW...WOULD EXPECT
BETTER LAKE SUPERIOR ACTIVITY TO REMAIN JUST WEST OF CHIPPEWA
COUNTY. DECISIVE DOWNTURN IN LAKE SNOW PARAMETERS EXPECTED AFTER
ABOUT 15Z...WITH STEADY LOSS OF SYNOPTIC MOISTURE SUPPORT AND
LOWERING INVERSION LEVELS. DIURNAL DISRUPTION WILL ONLY HELP THE
CAUSE..AS WILL DEEPENING OF SURFACE BASED DRY WEDGE. WOULD EXPECT
SCATTERED LATE MORNING ACTIVITY TO COMPLETELY END BY EARLY AFTERNOON
(YUP...SAID THAT BEFORE). UPSHOT TO ALL THE ABOVE...THINKING PERHAPS
ANOTHER INCH OR SO IN NORTHWEST LOWER SNOWBELTS THIS MORNING...LEAVING
THE INHERITED LAKE SNOW ADVISORY THROUGH ITS DURATION ENDING AT 15Z.
LESS ACCUMULATION EXPECTED ELSEWHERE. DRYING REMAINS AGGRESSIVE
THROUGH THE AFTERNOON...AND STILL EXPECT SKIES TO TREND PARTLY SUNNY
TO SUNNY ALL AREAS. UNFORTUNATELY...EVEN MID APRIL SUN WILL DO
LITTLE TO HELP THE TEMPERATURE CAUSE...WITH READINGS A SOLID 15 TO
20 DEGREES BELOW NORMAL. GUSTY NORTHWEST WINDS WILL SUBSIDE THROUGH
THE DAY...BUT NOT BEFORE MAKING IT FEEL DOWNRIGHT COLD THROUGH THE
EARLY AFTERNOON.
MUCH QUIETER HEADING INTO TONIGHT AS DRYING BECOMES COMPLETE AND
HIGH PRESSURE BUILDS DIRECTLY OVERHEAD. MOSTLY CLEAR SKIES...WITH
PERHAPS A TOUCH OF HIGH CLOUDS LATE. RADIATION COOLING TRIFECTA...
WITH QUICK LOSS OF WINDS...CLEAR SKIES..AND DRY LOW LEVELS. GUIDANCE
CONTINUES TO TREND COLDER...NOW SHOWING THE TRADITIONAL ICE BOX
LOCALES FLIRTING WITH THE UPPER SINGLE DIGITS. WILL NOT GO QUITE
THIS AGGRESSIVE...USING LOWER TEENS FOR THE COLDER LOCATIONS. THESE
NUMBERS FLIRT WITH RECORD LOWS FOR THE DAY...WITHIN A FEW DEGREES AT
SEVERAL SITES. COULD EASILY SEE A RECORD TO TWO BROKEN BY SUNRISE
SUNDAY.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 300 AM EDT SAT APR 20 2013
.SUNDAY AND MONDAY...STRONG SURFACE HIGH PRESSURE CENTER SHIFTS EAST
OF MICHIGAN BY 12Z SUNDAY. AFTER A FRIGID START TO THE DAY...WITH
EARLY MORNING LOWS IN THE TEENS (WHICH IS ROUGHLY 20 DEGREES BELOW
NORMAL)...TEMPS WILL REBOUND NICELY AS SOUTHERLY FLOW KICKS IN ON
THE BACK SIDE OF THE HIGH CENTER. CLOUDS WILL INCREASE/THICKEN/LOWER
FROM WEST TO EAST AS MAINLY MID/UPPER LEVEL MOISTURE BEGINS TO
ADVECT INTO THE WRN GREAT LAKES IN ADVANCE OF A COLD FRONT DRIVING
EAST THRU MINNESOTA. STILL APPEARS ANY PRECIP CHANCES WILL HOLD OFF
UNTIL SUNDAY NIGHT...AND WILL BE CONFINED TO MAINLY ERN UPR
MICHIGAN. ONCE THE COLD FRONT REACHES WRN UPR MICHIGAN AND
WISCONSIN...UPPER LEVEL FLOW BECOMES NEARLY PARALLEL WITH THE FRONT
ITSELF...WHICH WILL SLOW ITS EASTWARD PROGRESS. ALSO...A WAVE
DEVELOPS ALONG THE FRONT...DEEPENING INTO A CLOSED LOW THAT DRIVES
NE THRU THE STRAITS ON TUESDAY (MORE ON THIS BELOW). WITH THE SLOW
EASTWARD PUSH OF THE FRONT AND ASSOCIATED MOISTURE...POPS WILL
GRADUALLY SPREAD FROM ERN UPR MICHIGAN SUNDAY NIGHT INTO THE STRAITS
AND ALONG THE LAKE MICHIGAN SHORELINE TO LEELANAU COUNTY ON
MONDAY...AND THEN FINALLY MAKE SOME HEADWAY INTO NRN LWR MICHIGAN
WEST OF A LINE FROM ROGERS CITY TO HTL LATE MONDAY NIGHT AS THAT
WAVE (MENTIONED ABOVE) BEGINS TO LIFT INTO OUR CWA. AGAIN...TEMPS
WILL RECOVER NICELY DURING THE FIRST PART OF NEXT WEEK THANKS TO WAA
AHEAD OF THE SLOW COLD FRONT. HIGHS ON SUNDAY WILL WARM INTO THE MID
40S TO LOWER 50S...BUT WILL COOL BACK INTO THE 30S AT NIGHT.
HOWEVER...PRECIP SUNDAY NIGHT IN ERN UPR MICHIGAN SHOULD BE ALL
LIQUID PER NAM BUFR SOUNDINGS SHOWING A SURFACE-BASED ABOVE FREEZING
LAYER THRU 850 MB. WAA FURTHER STRENGTHENS ON MONDAY...WITH TEMPS
CLIMBING TO NEAR 50 IN ERN UPR MICHIGAN AND WELL INTO THE 50S TO
NEAR 60 ACROSS NRN LWR MICHIGAN. COLD FRONT REMAINS WEST OF OUR CWA
MONDAY NIGHT. TEMPS WILL COOLING MAINLY BACK INTO THE 40S MONDAY
NIGHT...KEEPING ANY PRECIP ALL LIQUID.
TUESDAY THRU FRIDAY...AS MENTIONED ABOVE...FIRST WAVE TRACKS ALONG
THE COLD FRONT AND THRU THE STRAITS TUESDAY MORNING. THIS FEATURE
COMBINED WITH DEEP MOISTURE WILL PRODUCE RAIN SHOWERS ACROSS MUCH OF
OUR CWA ON TUESDAY. SECOND WAVE DEVELOPS ALONG THE FRONT AND TRACKS
THRU SRN LWR MICHIGAN TUESDAY NIGHT...SPREADING ANOTHER AREA OF RAIN
SHOWERS THRU MOST OF MICHIGAN. WITH AREA RIVERS ALREADY RUNNING HIGH
FROM RECENT RAIN AND SNOWMELT...WILL NEED TO KEEP AN EYE ON THE
POTENTIAL FOR HEAVY RAINFALL ESPECIALLY WITH THIS SECOND WAVE AS IT
BEGINS TO TAP INTO GULF MOISTURE TUESDAY NIGHT. FOR NOW...WILL STICK
WITH LIKELY POPS FOR TUESDAY AND TUESDAY NIGHT ACROSS MOST OF OUR
CWA. PRECIP CHANCES DIMINISH ON WEDNESDAY AS THE FRONT EXITS TO THE
EAST COAST AND SURFACE RIDGING BUILDS INTO MICHIGAN. A WEAK
MOISTURE-STARVED NRN STREAM WAVE QUICKLY SWINGS THRU MICHIGAN
THURSDAY...PRODUCING A QUICK CHANCE OF LIGHT RAIN. DEEPER MOISTURE
WILL BEGIN TO ADVECT INTO THE WRN GREAT LAKES ON FRIDAY ONCE
SOUTHERLY RETURN FLOW KICKS IN ON THE BACK SIDE OF HIGH PRESSURE.
FIRST LOOK AT NEXT WEEKEND LOOKS UNSETTLED WITH NEAR NORMAL TEMPS IN
THE 50S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1247 PM EDT SAT APR 20 2013
ANY LINGERING LAKE EFFECT SNOW SHOWERS WILL END WITHIN THE FIRST
FEW HOURS OF THE TAF PERIOD...AS HIGH PRESSURE BUILDS BEHIND THE
DEPARTING STORM SYSTEM OVER QUEBEC. VFR CONDITIONS WILL PREVAIL
THROUGHOUT THE ENTIRE TAF PERIOD FOR ALL TAF SITES. SKIES WILL
CLEAR OUT THIS EVENING UNTIL A DECK OF MID-LEVEL CLOUDS OVERTAKE
NORTHERN MICHIGAN TOMORROW MORNING.
&&
.MARINE...
ISSUED AT 1052 AM EDT SAT APR 20 2013
UPDATE...GALES CONTINUE ACROSS PRESQUE ISLE...AND WILL EXTEND THE
GALE WARNING THROUGH 1-2 PM. ALL OTHER AREAS WILL BE IN THE SMALL
CRAFT ADVISORY FOR THE DAY. HEADLINES ARE EXPECTED TO BE LIFTED
MOST ALL AREAS BY EVENING (MAYBE NOT PRESQUE ISLE)...AS A QUICK
TRANSITION TO LIGHTER WINDS ARRIVES WITH HIGH PRESSURE.
SLOW...BUT STEADY...IMPROVEMENT EXPECTED ACROSS ALL WATERS
TODAY AS HIGH PRESSURE BUILDS INTO THE REGION. REMNANT GUSTY
NORTHWEST WINDS AND CHOPPY WAVES WILL REQUIRE SCA/S FOR NEARLY ALL
WATERS...BUT ALL GALE WARNINGS WILL BE ALLOWED TO EXPIRE BY 12Z.
RAPID IMPROVEMENT EXPECTED LATE THIS AFTERNOON AND EVENING AS WINDS
GO LIGHT UNDER OVERHEAD HIGH PRESSURE. GUSTY SOUTHEAST WINDS DEVELOP
SUNDAY...POSSIBLY REQUIRING ADDITIONAL SCA/S FOR SOME NEARSHORE
WATERS.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LHZ345-
346-349.
GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR LHZ347-348.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LMZ323-
341-342-344>346.
LS...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ321-
322.
&&
$$
UPDATE...SD
SYNOPSIS...TL
SHORT TERM...MB
LONG TERM...MR
AVIATION...TL
MARINE...MB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1054 AM EDT SAT APR 20 2013
.SYNOPSIS...
ISSUED AT 300 AM EDT SAT APR 20 2013
LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO IMPACT NORTHERN MICHIGAN
THIS MORNING...TARGETING THE TYPICAL SNOWBELT REGIONS OF EASTERN
UPPER AND NORTHWEST LOWER MICHIGAN FOR THE MOST PERSISTENT AND
HEAVIEST SNOW SHOWERS. HIGH PRESSURE WILL BEGIN TO SETTLE INTO THE
GREAT LAKES REGION THIS AFTERNOON...BRINGING QUIET AND SEASONABLY
CHILLY WEATHER TO NORTHERN MICHIGAN THROUGH THE REST OF THE WEEKEND.
THE NEXT CHANCE OF RAIN ARRIVES FOR THE BEGINNING OF THE WORK WEEK AS
WAVES OF LOW PRESSURE PUSH ACROSS THE REGION.
&&
.UPDATE...
ISSUED AT 1052 AM EDT SAT APR 20 2013
DOMINANT BAND OF MODERATE SNOWFALL CONTINUES TO DRIFT NE INTO
OTSEGO...CHARLEVOIX AND NRN CRAWFORD COUNTIES. ALTHOUGH THE
SNOWFALL IS RATHER IMPRESSIVE...ESPECIALLY FOR MID-LATE
APRIL...THE TIME OF YEAR/SUN ANGLE IS NOT ALLOWING SNOW TO
ACCUMULATE MUCH ANYMORE. WE DID HAVE REPORTS OF 1-2 INCHES OF SNOW
OVERNIGHT...AND THESE AMOUNTS WILL NOT BE MET TODAY. THIS IS ALSO
SUPPORTED BY AN EXPECTED TRANSITION TO MORE CELLULAR SHOWERS WITH
INCREASED LOW LEVEL LAPSE RATES...A LOSS OF CYCLONIC CONVERGENCE
AND DRY AIR ENTRAINMENT FROM INVADING HIGH PRESSURE UPSTREAM. WILL
AHVE SOME PEEKS OF SUN AT TIMES...BUT SKIES ARE EXPECTED TO CLEAR
MORE SO LATER THIS AFTERNOON...AS THE BETTER DRY AIR UPSTREAM
FILLS IN BEHIND FINAL SFC TROUGH FROM NRN WISCONSIN THROUGH
EASTERN LAKE SUPERIOR.
WILL ALLOW WINTER HEADLINES TO EXPIRE...WITH IMPACTS FROM
CONTINUED SNOW TO BE MINIMAL. ROADS WILL JUST BE WET FOR MOST ALL
AREAS WITHIN THE ADVISORY.
UPDATE ISSUED AT 717 AM EDT SAT APR 20 2013
MULTI-BAND LAKE EFFECT SNOW SHOWERS HAVE FULLY DEVELOPED ACROSS
OUR CWA...WITH THE DOMINANT BAND EXTENDING FROM NEAR ALDEN TO
KALKASKA. HEAVIER SNOW SHOWERS REMAIN EMBEDDED WITHIN THIS
DOMINANT BAND...WITH SNOWFALL RATES OF AROUND AN INCH AN HOUR.
WILL MAINTAIN THE LAKE SNOW ADVISORY FOR THE SNOWBELT REGION OF NW
AND N CENTRAL LWR MICHIGAN THRU LATE MORNING...AT WHICH TIME SNOW
SHOWERS SHOULD BEGIN TO BREAK DOWN AS HIGH PRESSURE AND DRIER AIR
BEGIN TO BUILD INTO THE WRN GREAT LAKES.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 300 AM EDT SAT APR 20 2013
WELL...THIS JUST ISN`T RIGHT FOR MID APRIL...COLD AND GUSTY
NORTHWEST WINDS...WITH NUMEROUS GROUND WHITENING LAKE INDUCED SNOW
SHOWERS TARGETING THE TRADITIONAL SNOW BELTS. CULPRIT BEHIND THIS
NONSENSE IS ANOMALOUSLY DEEP TROUGH EXTENDING FROM THE MID
MISSISSIPPI VALLEY UP THROUGH JAMES BAY. ATTENDANT BEHEMOTH SURFACE
LOW NOW WELL TO OUR NORTHEAST UP ACROSS CENTRAL QUEBEC...WITH
SURFACE TROUGH AXIS EXTENDING BACK SOUTHWEST INTO OUR AREA. COMBO OF
DEEP MOISTURE AND MORE THAN PLENTIFUL OVER-WATER INSTABILITY (H8
TEMPERATURES DOWN AROUND -14/-15C PER RAP ANALYSIS) HELPING DRIVE
THOSE LAKE SNOWS. FORECAST CONCERNS THROUGH THE SHORT TERM REAL CENTERED
WITHIN THE FIRST HALF OF TODAY...CENTERING ON LINGERING LAKE INDUCED
SNOW POTENTIAL AND POSSIBLE ADDITIONAL ACCUMULATIONS.
RESPECTABLE LAKE SNOW PARAMETERS REMAIN IN PLACE EARLY ON THIS
MORNING...WITH MORE THAN SUFFICIENT DELTA T/S AUGMENTED BY REMNANT
DEEPER MOISTURE AND GOOD INVERSION LEVELS UP THROUGH H7 LEVELS. NNW
(LAKE SUPERIOR) TO NW (NORTHERN LAKE MICHIGAN) FLOW REGIME WILL
LOCKED IN BY SUNRISE...TARGETING THE NORTHWEST LOWER SNOWBELTS FOR
THE MOST PERSISTENT AND HEAVIEST ACTIVITY. GIVEN FLOW...WOULD EXPECT
BETTER LAKE SUPERIOR ACTIVITY TO REMAIN JUST WEST OF CHIPPEWA
COUNTY. DECISIVE DOWNTURN IN LAKE SNOW PARAMETERS EXPECTED AFTER
ABOUT 15Z...WITH STEADY LOSS OF SYNOPTIC MOISTURE SUPPORT AND
LOWERING INVERSION LEVELS. DIURNAL DISRUPTION WILL ONLY HELP THE
CAUSE..AS WILL DEEPENING OF SURFACE BASED DRY WEDGE. WOULD EXPECT
SCATTERED LATE MORNING ACTIVITY TO COMPLETELY END BY EARLY AFTERNOON
(YUP...SAID THAT BEFORE). UPSHOT TO ALL THE ABOVE...THINKING PERHAPS
ANOTHER INCH OR SO IN NORTHWEST LOWER SNOWBELTS THIS MORNING...LEAVING
THE INHERITED LAKE SNOW ADVISORY THROUGH ITS DURATION ENDING AT 15Z.
LESS ACCUMULATION EXPECTED ELSEWHERE. DRYING REMAINS AGGRESSIVE
THROUGH THE AFTERNOON...AND STILL EXPECT SKIES TO TREND PARTLY SUNNY
TO SUNNY ALL AREAS. UNFORTUNATELY...EVEN MID APRIL SUN WILL DO
LITTLE TO HELP THE TEMPERATURE CAUSE...WITH READINGS A SOLID 15 TO
20 DEGREES BELOW NORMAL. GUSTY NORTHWEST WINDS WILL SUBSIDE THROUGH
THE DAY...BUT NOT BEFORE MAKING IT FEEL DOWNRIGHT COLD THROUGH THE
EARLY AFTERNOON.
MUCH QUIETER HEADING INTO TONIGHT AS DRYING BECOMES COMPLETE AND
HIGH PRESSURE BUILDS DIRECTLY OVERHEAD. MOSTLY CLEAR SKIES...WITH
PERHAPS A TOUCH OF HIGH CLOUDS LATE. RADIATION COOLING TRIFECTA...
WITH QUICK LOSS OF WINDS...CLEAR SKIES..AND DRY LOW LEVELS. GUIDANCE
CONTINUES TO TREND COLDER...NOW SHOWING THE TRADITIONAL ICE BOX
LOCALES FLIRTING WITH THE UPPER SINGLE DIGITS. WILL NOT GO QUITE
THIS AGGRESSIVE...USING LOWER TEENS FOR THE COLDER LOCATIONS. THESE
NUMBERS FLIRT WITH RECORD LOWS FOR THE DAY...WITHIN A FEW DEGREES AT
SEVERAL SITES. COULD EASILY SEE A RECORD TO TWO BROKEN BY SUNRISE
SUNDAY.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 300 AM EDT SAT APR 20 2013
.SUNDAY AND MONDAY...STRONG SURFACE HIGH PRESSURE CENTER SHIFTS EAST
OF MICHIGAN BY 12Z SUNDAY. AFTER A FRIGID START TO THE DAY...WITH
EARLY MORNING LOWS IN THE TEENS (WHICH IS ROUGHLY 20 DEGREES BELOW
NORMAL)...TEMPS WILL REBOUND NICELY AS SOUTHERLY FLOW KICKS IN ON
THE BACK SIDE OF THE HIGH CENTER. CLOUDS WILL INCREASE/THICKEN/LOWER
FROM WEST TO EAST AS MAINLY MID/UPPER LEVEL MOISTURE BEGINS TO
ADVECT INTO THE WRN GREAT LAKES IN ADVANCE OF A COLD FRONT DRIVING
EAST THRU MINNESOTA. STILL APPEARS ANY PRECIP CHANCES WILL HOLD OFF
UNTIL SUNDAY NIGHT...AND WILL BE CONFINED TO MAINLY ERN UPR
MICHIGAN. ONCE THE COLD FRONT REACHES WRN UPR MICHIGAN AND
WISCONSIN...UPPER LEVEL FLOW BECOMES NEARLY PARALLEL WITH THE FRONT
ITSELF...WHICH WILL SLOW ITS EASTWARD PROGRESS. ALSO...A WAVE
DEVELOPS ALONG THE FRONT...DEEPENING INTO A CLOSED LOW THAT DRIVES
NE THRU THE STRAITS ON TUESDAY (MORE ON THIS BELOW). WITH THE SLOW
EASTWARD PUSH OF THE FRONT AND ASSOCIATED MOISTURE...POPS WILL
GRADUALLY SPREAD FROM ERN UPR MICHIGAN SUNDAY NIGHT INTO THE STRAITS
AND ALONG THE LAKE MICHIGAN SHORELINE TO LEELANAU COUNTY ON
MONDAY...AND THEN FINALLY MAKE SOME HEADWAY INTO NRN LWR MICHIGAN
WEST OF A LINE FROM ROGERS CITY TO HTL LATE MONDAY NIGHT AS THAT
WAVE (MENTIONED ABOVE) BEGINS TO LIFT INTO OUR CWA. AGAIN...TEMPS
WILL RECOVER NICELY DURING THE FIRST PART OF NEXT WEEK THANKS TO WAA
AHEAD OF THE SLOW COLD FRONT. HIGHS ON SUNDAY WILL WARM INTO THE MID
40S TO LOWER 50S...BUT WILL COOL BACK INTO THE 30S AT NIGHT.
HOWEVER...PRECIP SUNDAY NIGHT IN ERN UPR MICHIGAN SHOULD BE ALL
LIQUID PER NAM BUFR SOUNDINGS SHOWING A SURFACE-BASED ABOVE FREEZING
LAYER THRU 850 MB. WAA FURTHER STRENGTHENS ON MONDAY...WITH TEMPS
CLIMBING TO NEAR 50 IN ERN UPR MICHIGAN AND WELL INTO THE 50S TO
NEAR 60 ACROSS NRN LWR MICHIGAN. COLD FRONT REMAINS WEST OF OUR CWA
MONDAY NIGHT. TEMPS WILL COOLING MAINLY BACK INTO THE 40S MONDAY
NIGHT...KEEPING ANY PRECIP ALL LIQUID.
TUESDAY THRU FRIDAY...AS MENTIONED ABOVE...FIRST WAVE TRACKS ALONG
THE COLD FRONT AND THRU THE STRAITS TUESDAY MORNING. THIS FEATURE
COMBINED WITH DEEP MOISTURE WILL PRODUCE RAIN SHOWERS ACROSS MUCH OF
OUR CWA ON TUESDAY. SECOND WAVE DEVELOPS ALONG THE FRONT AND TRACKS
THRU SRN LWR MICHIGAN TUESDAY NIGHT...SPREADING ANOTHER AREA OF RAIN
SHOWERS THRU MOST OF MICHIGAN. WITH AREA RIVERS ALREADY RUNNING HIGH
FROM RECENT RAIN AND SNOWMELT...WILL NEED TO KEEP AN EYE ON THE
POTENTIAL FOR HEAVY RAINFALL ESPECIALLY WITH THIS SECOND WAVE AS IT
BEGINS TO TAP INTO GULF MOISTURE TUESDAY NIGHT. FOR NOW...WILL STICK
WITH LIKELY POPS FOR TUESDAY AND TUESDAY NIGHT ACROSS MOST OF OUR
CWA. PRECIP CHANCES DIMINISH ON WEDNESDAY AS THE FRONT EXITS TO THE
EAST COAST AND SURFACE RIDGING BUILDS INTO MICHIGAN. A WEAK
MOISTURE-STARVED NRN STREAM WAVE QUICKLY SWINGS THRU MICHIGAN
THURSDAY...PRODUCING A QUICK CHANCE OF LIGHT RAIN. DEEPER MOISTURE
WILL BEGIN TO ADVECT INTO THE WRN GREAT LAKES ON FRIDAY ONCE
SOUTHERLY RETURN FLOW KICKS IN ON THE BACK SIDE OF HIGH PRESSURE.
FIRST LOOK AT NEXT WEEKEND LOOKS UNSETTLED WITH NEAR NORMAL TEMPS IN
THE 50S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 717 AM EDT SAT APR 20 2013
THE MOST PERSISTENT AND HEAVIEST LAKE EFFECT SNOW SHOWERS WILL
CONTINUE TO IMPACT LOCATIONS BETWEEN PLN...TVC AND APN. OVERALL
CONDITIONS AT OUR TAF SITES WILL BE VFR...OCCASIONALLY DROPPING TO
MVFR WITHIN SNOW SHOWERS THIS MORNING. SNOW SHOWERS WILL END BY
EARLY AFTERNOON AS HIGH PRESSURE BEGINS TO BUILD INTO THE WRN
GREAT LAKES REGION...WITH DECREASING CLOUDS THEREAFTER. GUSTY NW
WINDS WILL ALSO DIMINISH LATER THIS AFTERNOON AND EVENING.
&&
.MARINE...
ISSUED AT 1052 AM EDT SAT APR 20 2013
UPDATE...GALES CONTINUE ACROSS PRESQUE ISLE...AND WILL EXTEND THE
GALE WARNING THROUGH 1-2 PM. ALL OTHER AREAS WILL BE IN THE SMALL
CRAFT ADVISORY FOR THE DAY. HEADLINES ARE EXPECTED TO BE LIFTED
MOST ALL AREAS BY EVENING (MAYBE NOT PRESQUE ISLE)...AS A QUICK
TRANSITION TO LIGHTER WINDS ARRIVES WITH HIGH PRESSURE.
SLOW...BUT STEADY...IMPROVEMENT EXPECTED ACROSS ALL WATERS
TODAY AS HIGH PRESSURE BUILDS INTO THE REGION. REMNANT GUSTY
NORTHWEST WINDS AND CHOPPY WAVES WILL REQUIRE SCA/S FOR NEARLY ALL
WATERS...BUT ALL GALE WARNINGS WILL BE ALLOWED TO EXPIRE BY 12Z.
RAPID IMPROVEMENT EXPECTED LATE THIS AFTERNOON AND EVENING AS WINDS
GO LIGHT UNDER OVERHEAD HIGH PRESSURE. GUSTY SOUTHEAST WINDS DEVELOP
SUNDAY...POSSIBLY REQUIRING ADDITIONAL SCA/S FOR SOME NEARSHORE
WATERS.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LHZ345-
346-349.
GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR LHZ347-348.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LMZ323-
341-342-344>346.
LS...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ321-
322.
&&
$$
UPDATE...SD
SYNOPSIS...MR
SHORT TERM...MB
LONG TERM...MR
AVIATION...MR
MARINE...MB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
718 AM EDT SAT APR 20 2013
.SYNOPSIS...
ISSUED AT 300 AM EDT SAT APR 20 2013
LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO IMPACT NORTHERN MICHIGAN
THIS MORNING...TARGETING THE TYPICAL SNOWBELT REGIONS OF EASTERN
UPPER AND NORTHWEST LOWER MICHIGAN FOR THE MOST PERSISTENT AND
HEAVIEST SNOW SHOWERS. HIGH PRESSURE WILL BEGIN TO SETTLE INTO THE
GREAT LAKES REGION THIS AFTERNOON...BRINGING QUIET AND SEASONABLY
CHILLY WEATHER TO NORTHERN MICHIGAN THROUGH THE REST OF THE WEEKEND.
THE NEXT CHANCE OF RAIN ARRIVES FOR THE BEGINNING OF THE WORK WEEK AS
WAVES OF LOW PRESSURE PUSH ACROSS THE REGION.
&&
.UPDATE...
ISSUED AT 717 AM EDT SAT APR 20 2013
MULTI-BAND LAKE EFFECT SNOW SHOWERS HAVE FULLY DEVELOPED ACROSS
OUR CWA...WITH THE DOMINANT BAND EXTENDING FROM NEAR ALDEN TO
KALKASKA. HEAVIER SNOW SHOWERS REMAIN EMBEDDED WITHIN THIS
DOMINANT BAND...WITH SNOWFALL RATES OF AROUND AN INCH AN HOUR.
WILL MAINTAIN THE LAKE SNOW ADVISORY FOR THE SNOWBELT REGION OF NW
AND N CENTRAL LWR MICHIGAN THRU LATE MORNING...AT WHICH TIME SNOW
SHOWERS SHOULD BEGIN TO BREAK DOWN AS HIGH PRESSURE AND DRIER AIR
BEGIN TO BUILD INTO THE WRN GREAT LAKES.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 300 AM EDT SAT APR 20 2013
WELL...THIS JUST ISN`T RIGHT FOR MID APRIL...COLD AND GUSTY
NORTHWEST WINDS...WITH NUMEROUS GROUND WHITENING LAKE INDUCED SNOW
SHOWERS TARGETING THE TRADITIONAL SNOW BELTS. CULPRIT BEHIND THIS
NONSENSE IS ANOMALOUSLY DEEP TROUGH EXTENDING FROM THE MID
MISSISSIPPI VALLEY UP THROUGH JAMES BAY. ATTENDANT BEHEMOTH SURFACE
LOW NOW WELL TO OUR NORTHEAST UP ACROSS CENTRAL QUEBEC...WITH
SURFACE TROUGH AXIS EXTENDING BACK SOUTHWEST INTO OUR AREA. COMBO OF
DEEP MOISTURE AND MORE THAN PLENTIFUL OVER-WATER INSTABILITY (H8
TEMPERATURES DOWN AROUND -14/-15C PER RAP ANALYSIS) HELPING DRIVE
THOSE LAKE SNOWS. FORECAST CONCERNS THROUGH THE SHORT TERM REAL CENTERED
WITHIN THE FIRST HALF OF TODAY...CENTERING ON LINGERING LAKE INDUCED
SNOW POTENTIAL AND POSSIBLE ADDITIONAL ACCUMULATIONS.
RESPECTABLE LAKE SNOW PARAMETERS REMAIN IN PLACE EARLY ON THIS
MORNING...WITH MORE THAN SUFFICIENT DELTA T/S AUGMENTED BY REMNANT
DEEPER MOISTURE AND GOOD INVERSION LEVELS UP THROUGH H7 LEVELS. NNW
(LAKE SUPERIOR) TO NW (NORTHERN LAKE MICHIGAN) FLOW REGIME WILL
LOCKED IN BY SUNRISE...TARGETING THE NORTHWEST LOWER SNOWBELTS FOR
THE MOST PERSISTENT AND HEAVIEST ACTIVITY. GIVEN FLOW...WOULD EXPECT
BETTER LAKE SUPERIOR ACTIVITY TO REMAIN JUST WEST OF CHIPPEWA
COUNTY. DECISIVE DOWNTURN IN LAKE SNOW PARAMETERS EXPECTED AFTER
ABOUT 15Z...WITH STEADY LOSS OF SYNOPTIC MOISTURE SUPPORT AND
LOWERING INVERSION LEVELS. DIURNAL DISRUPTION WILL ONLY HELP THE
CAUSE..AS WILL DEEPENING OF SURFACE BASED DRY WEDGE. WOULD EXPECT
SCATTERED LATE MORNING ACTIVITY TO COMPLETELY END BY EARLY AFTERNOON
(YUP...SAID THAT BEFORE). UPSHOT TO ALL THE ABOVE...THINKING PERHAPS
ANOTHER INCH OR SO IN NORTHWEST LOWER SNOWBELTS THIS MORNING...LEAVING
THE INHERITED LAKE SNOW ADVISORY THROUGH ITS DURATION ENDING AT 15Z.
LESS ACCUMULATION EXPECTED ELSEWHERE. DRYING REMAINS AGGRESSIVE
THROUGH THE AFTERNOON...AND STILL EXPECT SKIES TO TREND PARTLY SUNNY
TO SUNNY ALL AREAS. UNFORTUNATELY...EVEN MID APRIL SUN WILL DO
LITTLE TO HELP THE TEMPERATURE CAUSE...WITH READINGS A SOLID 15 TO
20 DEGREES BELOW NORMAL. GUSTY NORTHWEST WINDS WILL SUBSIDE THROUGH
THE DAY...BUT NOT BEFORE MAKING IT FEEL DOWNRIGHT COLD THROUGH THE
EARLY AFTERNOON.
MUCH QUIETER HEADING INTO TONIGHT AS DRYING BECOMES COMPLETE AND
HIGH PRESSURE BUILDS DIRECTLY OVERHEAD. MOSTLY CLEAR SKIES...WITH
PERHAPS A TOUCH OF HIGH CLOUDS LATE. RADIATION COOLING TRIFECTA...
WITH QUICK LOSS OF WINDS...CLEAR SKIES..AND DRY LOW LEVELS. GUIDANCE
CONTINUES TO TREND COLDER...NOW SHOWING THE TRADITIONAL ICE BOX
LOCALES FLIRTING WITH THE UPPER SINGLE DIGITS. WILL NOT GO QUITE
THIS AGGRESSIVE...USING LOWER TEENS FOR THE COLDER LOCATIONS. THESE
NUMBERS FLIRT WITH RECORD LOWS FOR THE DAY...WITHIN A FEW DEGREES AT
SEVERAL SITES. COULD EASILY SEE A RECORD TO TWO BROKEN BY SUNRISE
SUNDAY.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 300 AM EDT SAT APR 20 2013
.SUNDAY AND MONDAY...STRONG SURFACE HIGH PRESSURE CENTER SHIFTS EAST
OF MICHIGAN BY 12Z SUNDAY. AFTER A FRIGID START TO THE DAY...WITH
EARLY MORNING LOWS IN THE TEENS (WHICH IS ROUGHLY 20 DEGREES BELOW
NORMAL)...TEMPS WILL REBOUND NICELY AS SOUTHERLY FLOW KICKS IN ON
THE BACK SIDE OF THE HIGH CENTER. CLOUDS WILL INCREASE/THICKEN/LOWER
FROM WEST TO EAST AS MAINLY MID/UPPER LEVEL MOISTURE BEGINS TO
ADVECT INTO THE WRN GREAT LAKES IN ADVANCE OF A COLD FRONT DRIVING
EAST THRU MINNESOTA. STILL APPEARS ANY PRECIP CHANCES WILL HOLD OFF
UNTIL SUNDAY NIGHT...AND WILL BE CONFINED TO MAINLY ERN UPR
MICHIGAN. ONCE THE COLD FRONT REACHES WRN UPR MICHIGAN AND
WISCONSIN...UPPER LEVEL FLOW BECOMES NEARLY PARALLEL WITH THE FRONT
ITSELF...WHICH WILL SLOW ITS EASTWARD PROGRESS. ALSO...A WAVE
DEVELOPS ALONG THE FRONT...DEEPENING INTO A CLOSED LOW THAT DRIVES
NE THRU THE STRAITS ON TUESDAY (MORE ON THIS BELOW). WITH THE SLOW
EASTWARD PUSH OF THE FRONT AND ASSOCIATED MOISTURE...POPS WILL
GRADUALLY SPREAD FROM ERN UPR MICHIGAN SUNDAY NIGHT INTO THE STRAITS
AND ALONG THE LAKE MICHIGAN SHORELINE TO LEELANAU COUNTY ON
MONDAY...AND THEN FINALLY MAKE SOME HEADWAY INTO NRN LWR MICHIGAN
WEST OF A LINE FROM ROGERS CITY TO HTL LATE MONDAY NIGHT AS THAT
WAVE (MENTIONED ABOVE) BEGINS TO LIFT INTO OUR CWA. AGAIN...TEMPS
WILL RECOVER NICELY DURING THE FIRST PART OF NEXT WEEK THANKS TO WAA
AHEAD OF THE SLOW COLD FRONT. HIGHS ON SUNDAY WILL WARM INTO THE MID
40S TO LOWER 50S...BUT WILL COOL BACK INTO THE 30S AT NIGHT.
HOWEVER...PRECIP SUNDAY NIGHT IN ERN UPR MICHIGAN SHOULD BE ALL
LIQUID PER NAM BUFR SOUNDINGS SHOWING A SURFACE-BASED ABOVE FREEZING
LAYER THRU 850 MB. WAA FURTHER STRENGTHENS ON MONDAY...WITH TEMPS
CLIMBING TO NEAR 50 IN ERN UPR MICHIGAN AND WELL INTO THE 50S TO
NEAR 60 ACROSS NRN LWR MICHIGAN. COLD FRONT REMAINS WEST OF OUR CWA
MONDAY NIGHT. TEMPS WILL COOLING MAINLY BACK INTO THE 40S MONDAY
NIGHT...KEEPING ANY PRECIP ALL LIQUID.
TUESDAY THRU FRIDAY...AS MENTIONED ABOVE...FIRST WAVE TRACKS ALONG
THE COLD FRONT AND THRU THE STRAITS TUESDAY MORNING. THIS FEATURE
COMBINED WITH DEEP MOISTURE WILL PRODUCE RAIN SHOWERS ACROSS MUCH OF
OUR CWA ON TUESDAY. SECOND WAVE DEVELOPS ALONG THE FRONT AND TRACKS
THRU SRN LWR MICHIGAN TUESDAY NIGHT...SPREADING ANOTHER AREA OF RAIN
SHOWERS THRU MOST OF MICHIGAN. WITH AREA RIVERS ALREADY RUNNING HIGH
FROM RECENT RAIN AND SNOWMELT...WILL NEED TO KEEP AN EYE ON THE
POTENTIAL FOR HEAVY RAINFALL ESPECIALLY WITH THIS SECOND WAVE AS IT
BEGINS TO TAP INTO GULF MOISTURE TUESDAY NIGHT. FOR NOW...WILL STICK
WITH LIKELY POPS FOR TUESDAY AND TUESDAY NIGHT ACROSS MOST OF OUR
CWA. PRECIP CHANCES DIMINISH ON WEDNESDAY AS THE FRONT EXITS TO THE
EAST COAST AND SURFACE RIDGING BUILDS INTO MICHIGAN. A WEAK
MOISTURE-STARVED NRN STREAM WAVE QUICKLY SWINGS THRU MICHIGAN
THURSDAY...PRODUCING A QUICK CHANCE OF LIGHT RAIN. DEEPER MOISTURE
WILL BEGIN TO ADVECT INTO THE WRN GREAT LAKES ON FRIDAY ONCE
SOUTHERLY RETURN FLOW KICKS IN ON THE BACK SIDE OF HIGH PRESSURE.
FIRST LOOK AT NEXT WEEKEND LOOKS UNSETTLED WITH NEAR NORMAL TEMPS IN
THE 50S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 717 AM EDT SAT APR 20 2013
THE MOST PERSISTENT AND HEAVIEST LAKE EFFECT SNOW SHOWERS WILL
CONTINUE TO IMPACT LOCATIONS BETWEEN PLN...TVC AND APN. OVERALL
CONDITIONS AT OUR TAF SITES WILL BE VFR...OCCASIONALLY DROPPING TO
MVFR WITHIN SNOW SHOWERS THIS MORNING. SNOW SHOWERS WILL END BY
EARLY AFTERNOON AS HIGH PRESSURE BEGINS TO BUILD INTO THE WRN
GREAT LAKES REGION...WITH DECREASING CLOUDS THEREAFTER. GUSTY NW
WINDS WILL ALSO DIMINISH LATER THIS AFTERNOON AND EVENING.
&&
.MARINE...
ISSUED AT 300 AM EDT SAT APR 20 2013
SLOW...BUT STEADY...IMPROVEMENT EXPECTED ACROSS ALL WATERS
TODAY AS HIGH PRESSURE BUILDS INTO THE REGION. REMNANT GUSTY
NORTHWEST WINDS AND CHOPPY WAVES WILL REQUIRE SCA/S FOR NEARLY ALL
WATERS...BUT ALL GALE WARNINGS WILL BE ALLOWED TO EXPIRE BY 12Z.
RAPID IMPROVEMENT EXPECTED LATE THIS AFTERNOON AND EVENING AS WINDS
GO LIGHT UNDER OVERHEAD HIGH PRESSURE. GUSTY SOUTHEAST WINDS DEVELOP
SUNDAY...POSSIBLY REQUIRING ADDITIONAL SCA/S FOR SOME NEARSHORE
WATERS.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...LAKE EFFECT SNOW ADVISORY UNTIL 11 AM EDT THIS MORNING FOR
MIZ021-022-027-028.
LH...GALE WARNING UNTIL 11 AM EDT THIS MORNING FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR
LMZ323- 341-342-344>346.
LS...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR
LSZ321- 322.
&&
$$
UPDATE...MR
SYNOPSIS...MR
SHORT TERM...MB
LONG TERM...MR
AVIATION...MR
MARINE...MB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
300 AM EDT SAT APR 20 2013
.SYNOPSIS...
ISSUED AT 300 AM EDT SAT APR 20 2013
LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO IMPACT NORTHERN MICHIGAN
THIS MORNING...TARGETING THE TYPICAL SNOWBELT REGIONS OF EASTERN
UPPER AND NORTHWEST LOWER MICHIGAN FOR THE MOST PERSISTENT AND
HEAVIEST SNOW SHOWERS. HIGH PRESSURE WILL BEGIN TO SETTLE INTO THE
GREAT LAKES REGION THIS AFTERNOON...BRINGING QUIET AND SEASONABLY
CHILLY WEATHER TO NORTHERN MICHIGAN THROUGH THE REST OF THE WEEKEND.
THE NEXT CHANCE OF RAIN ARRIVES FOR THE BEGINNING OF THE WORK WEEK AS
WAVES OF LOW PRESSURE PUSH ACROSS THE REGION.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 300 AM EDT SAT APR 20 2013
WELL...THIS JUST ISN`T RIGHT FOR MID APRIL...COLD AND GUSTY
NORTHWEST WINDS...WITH NUMEROUS GROUND WHITENING LAKE INDUCED SNOW
SHOWERS TARGETING THE TRADITIONAL SNOW BELTS. CULPRIT BEHIND THIS
NONSENSE IS ANOMALOUSLY DEEP TROUGH EXTENDING FROM THE MID
MISSISSIPPI VALLEY UP THROUGH JAMES BAY. ATTENDANT BEHEMOTH SURFACE
LOW NOW WELL TO OUR NORTHEAST UP ACROSS CENTRAL QUEBEC...WITH
SURFACE TROUGH AXIS EXTENDING BACK SOUTHWEST INTO OUR AREA. COMBO OF
DEEP MOISTURE AND MORE THAN PLENTIFUL OVER-WATER INSTABILITY (H8
TEMPERATURES DOWN AROUND -14/-15C PER RAP ANALYSIS) HELPING DRIVE
THOSE LAKE SNOWS. FORECAST CONCERNS THROUGH THE SHORT TERM REAL CENTERED
WITHIN THE FIRST HALF OF TODAY...CENTERING ON LINGERING LAKE INDUCED
SNOW POTENTIAL AND POSSIBLE ADDITIONAL ACCUMULATIONS.
RESPECTABLE LAKE SNOW PARAMETERS REMAIN IN PLACE EARLY ON THIS
MORNING...WITH MORE THAN SUFFICIENT DELTA T/S AUGMENTED BY REMNANT
DEEPER MOISTURE AND GOOD INVERSION LEVELS UP THROUGH H7 LEVELS. NNW
(LAKE SUPERIOR) TO NW (NORTHERN LAKE MICHIGAN) FLOW REGIME WILL
LOCKED IN BY SUNRISE...TARGETING THE NORTHWEST LOWER SNOWBELTS FOR
THE MOST PERSISTENT AND HEAVIEST ACTIVITY. GIVEN FLOW...WOULD EXPECT
BETTER LAKE SUPERIOR ACTIVITY TO REMAIN JUST WEST OF CHIPPEWA
COUNTY. DECISIVE DOWNTURN IN LAKE SNOW PARAMETERS EXPECTED AFTER
ABOUT 15Z...WITH STEADY LOSS OF SYNOPTIC MOISTURE SUPPORT AND
LOWERING INVERSION LEVELS. DIURNAL DISRUPTION WILL ONLY HELP THE
CAUSE..AS WILL DEEPENING OF SURFACE BASED DRY WEDGE. WOULD EXPECT
SCATTERED LATE MORNING ACTIVITY TO COMPLETELY END BY EARLY AFTERNOON
(YUP...SAID THAT BEFORE). UPSHOT TO ALL THE ABOVE...THINKING PERHAPS
ANOTHER INCH OR SO IN NORTHWEST LOWER SNOWBELTS THIS MORNING...LEAVING
THE INHERITED LAKE SNOW ADVISORY THROUGH ITS DURATION ENDING AT 15Z.
LESS ACCUMULATION EXPECTED ELSEWHERE. DRYING REMAINS AGGRESSIVE
THROUGH THE AFTERNOON...AND STILL EXPECT SKIES TO TREND PARTLY SUNNY
TO SUNNY ALL AREAS. UNFORTUNATELY...EVEN MID APRIL SUN WILL DO
LITTLE TO HELP THE TEMPERATURE CAUSE...WITH READINGS A SOLID 15 TO
20 DEGREES BELOW NORMAL. GUSTY NORTHWEST WINDS WILL SUBSIDE THROUGH
THE DAY...BUT NOT BEFORE MAKING IT FEEL DOWNRIGHT COLD THROUGH THE
EARLY AFTERNOON.
MUCH QUIETER HEADING INTO TONIGHT AS DRYING BECOMES COMPLETE AND
HIGH PRESSURE BUILDS DIRECTLY OVERHEAD. MOSTLY CLEAR SKIES...WITH
PERHAPS A TOUCH OF HIGH CLOUDS LATE. RADIATION COOLING TRIFECTA...
WITH QUICK LOSS OF WINDS...CLEAR SKIES..AND DRY LOW LEVELS. GUIDANCE
CONTINUES TO TREND COLDER...NOW SHOWING THE TRADITIONAL ICE BOX
LOCALES FLIRTING WITH THE UPPER SINGLE DIGITS. WILL NOT GO QUITE
THIS AGGRESSIVE...USING LOWER TEENS FOR THE COLDER LOCATIONS. THESE
NUMBERS FLIRT WITH RECORD LOWS FOR THE DAY...WITHIN A FEW DEGREES AT
SEVERAL SITES. COULD EASILY SEE A RECORD TO TWO BROKEN BY SUNRISE
SUNDAY.
&&
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 300 AM EDT SAT APR 20 2013
.SUNDAY AND MONDAY...STRONG SURFACE HIGH PRESSURE CENTER SHIFTS EAST
OF MICHIGAN BY 12Z SUNDAY. AFTER A FRIGID START TO THE DAY...WITH
EARLY MORNING LOWS IN THE TEENS (WHICH IS ROUGHLY 20 DEGREES BELOW
NORMAL)...TEMPS WILL REBOUND NICELY AS SOUTHERLY FLOW KICKS IN ON
THE BACK SIDE OF THE HIGH CENTER. CLOUDS WILL INCREASE/THICKEN/LOWER
FROM WEST TO EAST AS MAINLY MID/UPPER LEVEL MOISTURE BEGINS TO
ADVECT INTO THE WRN GREAT LAKES IN ADVANCE OF A COLD FRONT DRIVING
EAST THRU MINNESOTA. STILL APPEARS ANY PRECIP CHANCES WILL HOLD OFF
UNTIL SUNDAY NIGHT...AND WILL BE CONFINED TO MAINLY ERN UPR
MICHIGAN. ONCE THE COLD FRONT REACHES WRN UPR MICHIGAN AND
WISCONSIN...UPPER LEVEL FLOW BECOMES NEARLY PARALLEL WITH THE FRONT
ITSELF...WHICH WILL SLOW ITS EASTWARD PROGRESS. ALSO...A WAVE
DEVELOPS ALONG THE FRONT...DEEPENING INTO A CLOSED LOW THAT DRIVES
NE THRU THE STRAITS ON TUESDAY (MORE ON THIS BELOW). WITH THE SLOW
EASTWARD PUSH OF THE FRONT AND ASSOCIATED MOISTURE...POPS WILL
GRADUALLY SPREAD FROM ERN UPR MICHIGAN SUNDAY NIGHT INTO THE STRAITS
AND ALONG THE LAKE MICHIGAN SHORELINE TO LEELANAU COUNTY ON
MONDAY...AND THEN FINALLY MAKE SOME HEADWAY INTO NRN LWR MICHIGAN
WEST OF A LINE FROM ROGERS CITY TO HTL LATE MONDAY NIGHT AS THAT
WAVE (MENTIONED ABOVE) BEGINS TO LIFT INTO OUR CWA. AGAIN...TEMPS
WILL RECOVER NICELY DURING THE FIRST PART OF NEXT WEEK THANKS TO WAA
AHEAD OF THE SLOW COLD FRONT. HIGHS ON SUNDAY WILL WARM INTO THE MID
40S TO LOWER 50S...BUT WILL COOL BACK INTO THE 30S AT NIGHT.
HOWEVER...PRECIP SUNDAY NIGHT IN ERN UPR MICHIGAN SHOULD BE ALL
LIQUID PER NAM BUFR SOUNDINGS SHOWING A SURFACE-BASED ABOVE FREEZING
LAYER THRU 850 MB. WAA FURTHER STRENGTHENS ON MONDAY...WITH TEMPS
CLIMBING TO NEAR 50 IN ERN UPR MICHIGAN AND WELL INTO THE 50S TO
NEAR 60 ACROSS NRN LWR MICHIGAN. COLD FRONT REMAINS WEST OF OUR CWA
MONDAY NIGHT. TEMPS WILL COOLING MAINLY BACK INTO THE 40S MONDAY
NIGHT...KEEPING ANY PRECIP ALL LIQUID.
TUESDAY THRU FRIDAY...AS MENTIONED ABOVE...FIRST WAVE TRACKS ALONG
THE COLD FRONT AND THRU THE STRAITS TUESDAY MORNING. THIS FEATURE
COMBINED WITH DEEP MOISTURE WILL PRODUCE RAIN SHOWERS ACROSS MUCH OF
OUR CWA ON TUESDAY. SECOND WAVE DEVELOPS ALONG THE FRONT AND TRACKS
THRU SRN LWR MICHIGAN TUESDAY NIGHT...SPREADING ANOTHER AREA OF RAIN
SHOWERS THRU MOST OF MICHIGAN. WITH AREA RIVERS ALREADY RUNNING HIGH
FROM RECENT RAIN AND SNOWMELT...WILL NEED TO KEEP AN EYE ON THE
POTENTIAL FOR HEAVY RAINFALL ESPECIALLY WITH THIS SECOND WAVE AS IT
BEGINS TO TAP INTO GULF MOISTURE TUESDAY NIGHT. FOR NOW...WILL STICK
WITH LIKELY POPS FOR TUESDAY AND TUESDAY NIGHT ACROSS MOST OF OUR
CWA. PRECIP CHANCES DIMINISH ON WEDNESDAY AS THE FRONT EXITS TO THE
EAST COAST AND SURFACE RIDGING BUILDS INTO MICHIGAN. A WEAK
MOISTURE-STARVED NRN STREAM WAVE QUICKLY SWINGS THRU MICHIGAN
THURSDAY...PRODUCING A QUICK CHANCE OF LIGHT RAIN. DEEPER MOISTURE
WILL BEGIN TO ADVECT INTO THE WRN GREAT LAKES ON FRIDAY ONCE
SOUTHERLY RETURN FLOW KICKS IN ON THE BACK SIDE OF HIGH PRESSURE.
FIRST LOOK AT NEXT WEEKEND LOOKS UNSETTLED WITH NEAR NORMAL TEMPS IN
THE 50S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1204 AM EDT SAT APR 20 2013
LOW PRESSURE NORTH OF GEORGIAN BAY WILL WEAKEN AND RAPIDLY MOVE
EAST. BLUSTERY W TO NW WINDS WILL CONTINUE INTO SATURDAY...THEN GO
LIGHT/VARIABLE. COLDER AIR WILL CONTINUE TO SPILL INTO THE
REGION...AND LAKE EFFECT SNOW SHOWERS ARE ORGANIZING. HOWEVER...THE
MAIN IMPACT WILL BE BETWEEN TVC AND PLN. DO EXPECT CIGS/VSBYS AT
TVC/PLN TO LOWER TO MVFR LEVELS...AND VSBYS WILL REACH IFR
CONDITIONS IN -SHSN AT TIMES...ESPECIALLY AT TVC. PRECIP AND
CLOUDS DIMINISH DURING THE DAY ON SATURDAY.
&&
.MARINE...
ISSUED AT 300 AM EDT SAT APR 20 2013
SLOW...BUT STEADY...IMPROVEMENT EXPECTED ACROSS ALL WATERS
TODAY AS HIGH PRESSURE BUILDS INTO THE REGION. REMNANT GUSTY
NORTHWEST WINDS AND CHOPPY WAVES WILL REQUIRE SCA/S FOR NEARLY ALL
WATERS...BUT ALL GALE WARNINGS WILL BE ALLOWED TO EXPIRE BY 12Z.
RAPID IMPROVEMENT EXPECTED LATE THIS AFTERNOON AND EVENING AS WINDS
GO LIGHT UNDER OVERHEAD HIGH PRESSURE. GUSTY SOUTHEAST WINDS DEVELOP
SUNDAY...POSSIBLY REQUIRING ADDITIONAL SCA/S FOR SOME NEARSHORE
WATERS.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...LAKE EFFECT SNOW ADVISORY UNTIL 11 AM EDT THIS MORNING FOR
MIZ021-022-027-028.
WINTER WEATHER ADVISORY UNTIL 5 AM EDT EARLY THIS MORNING FOR
MIZ008.
LH...GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LMZ323-
341-342-344>346.
LS...GALE WARNING UNTIL 6 AM EDT EARLY THIS MORNING FOR LSZ321-322.
&&
$$
SYNOPSIS...MR
SHORT TERM...MB
LONG TERM...MR
AVIATION...JZ
MARINE...MB
AREA FORECAST DISCUSSION
NWS DULUTH MN
1025 PM CDT SUN APR 21 2013
.UPDATE...
RADAR SHOWS THE MAIN PRECIPITATION AREA MOVING THROUGH FAR EASTERN
MINNESOTA AND NORTHWEST WISCONSIN...AND IT WAS DECREASING IN
INTENSITY. DRIZZLE OR LIGHT SNOW WAS STILL OCCURRING FROM COOK
THROUGH THE TWIN PORTS TOWARD SIREN...BUT THIS SHOULD BE
DIMINISHING AS WELL.
LOOKING AHEAD...THE LATEST NAM IS INDICATING A GREATER THREAT FOR
SOME SIGNIFICANT SNOW OVER A PORTION OF OUR CWA...MAINLY OVER
NORTHWEST WISCONSIN. EVEN AREAS AS FAR WEST AND NORTH AS
BRAINERD...THE TWIN PORTS AND THE NORTH SHORE AREA WILL SEE SOME
ACCUMULATING SNOW. HOW MUCH IS STILL IN QUESTION...AS WE WANT TO
SEE THE GFS/ECMWF BEFORE JUMPING ON HEADLINES. THE NAM DOES SHOW
IMPRESSIVE FGEN OVER OUR CWA...ALONG THE TIGHT THERMAL GRADIENT. IT
DOES LOOK LIKELY WE`LL NEED AT LEAST SOME ADVISORIES...AND IF THE
NAM IS CORRECT...WARNINGS MAY ALSO BE NEEDED ACROSS MUCH OF OUR NORTHWEST
WISCONSIN ZONES. THERE WILL BE A TRANSITION TO MIXED PRECIPITATION OR
LIQUID OVER PORTIONS OF PRICE/SAWYER/IRON COUNTIES WHICH WILL
FURTHER COMPLICATE SNOW AMOUNTS THERE. STAY TUNED TO LATER
FORECASTS AND DISCUSSIONS ON THIS DEVELOPING SPRING STORM.
&&
.PREV DISCUSSION... /ISSUED 642 PM CDT SUN APR 21 2013/
UPDATE...
RAIN AND SNOW WAS OCCURRING OVER A GOOD PORTION OF THE EASTERN
HALF OF MINNESOTA INTO WESTERN WISCONSIN THIS EVENING. SNOW WAS
DOMINANT ACROSS THE FAR NORTHERN PORTION OF OUR CWA...AND WAS
OCCURRING AT KDLH. THE RAP AND NAM BOTH INDICATE WET BULB ZERO
LEVELS SHOULD HAVE INCREASED QUITE A BIT BETWEEN 21Z AND 00Z
OVER THE SOUTHERN HALF OF THE CWA. HOWEVER...KDLH REMAINS MOSTLY
SNOW BUT WE DO EXPECT A MIX TO OCCUR AS PRECIP RATES DIMINISH. WE
ADJUSTED PRECIP TYPE/POPS A BIT EARLIER THIS EVENING...AND WILL DO
SO AS THE PRECIP DIMINISHES FROM WEST TO EAST OVERNIGHT.
AVIATION...00Z TAFS
IFR OR MVFR CONDITIONS COVERED THE NORTHLAND THIS EVENING...AND
THAT IS EXPECTED TO CONTINUE OVERNIGHT. AN AREA OF SNOW/RAIN
COVERED MOST OF NORTHEAST MINNESOTA AND NORTHWEST WISCONSIN...WITH
RADAR SHOWING THE PRECIPITATION DIMINISHING FROM WEST TO EAST. THAT
TREND WILL CONTINUE OVERNIGHT...WITH MOST OF THE PRECIPITATION
EXITING EASTERN MINNESOTA BETWEEN 03-06Z...AND NORTHWEST
WISCONSIN BETWEEN 05-08Z. IFR OR MVFR CONDITIONS WILL REMAIN...AND
WE EXPECT IMPROVEMENT MONDAY MORNING...BEFORE YET ANOTHER SYSTEM
WILL BRING LOWER CEILINGS AND MORE SNOW TO THE NORTHLAND. THE BEST
CHANCE FOR ADDITIONAL SNOW WILL BE OVER EAST CENTRAL MINNESOTA AND
NORTHWEST WISCONSIN OVER OUR CWA.
PREV DISCUSSION... /ISSUED 306 PM CDT SUN APR 21 2013/
SHORT TERM.../NOW - MONDAY/
THROUGH TONIGHT...THE FOCUS FOR THIS FORECAST IS THE PCPN
ASSOCIATED WITH AN APPROACHING COLD FRONT THAT IS ALREADY MOVING
INTO THE WESTERN FORECAST AREA. THE NORTHLAND IS EXPECTED TO HAVE
THIS PCPN MOVE THROUGH THE REGION FROM WEST TO EAST THROUGH
TONIGHT. WHILE ARE MOSTLY FORECASTING RAIN WITH LITTLE TO NO SNOW
ACCUMULATION...THERE IS STILL SOME UNCERTAINTY AS TO PCPN TYPE AND
SNOWFALL ACCUMULATION SINCE THE TEMPERATURES ACROSS THE NORTHLAND
ARE ONLY IN THE MID TO UPPER 30S. BASED ON MODEL SOUNDINGS...THE
SNOW IS DEFINITELY FALLING AS SNOW ALOFT...BUT THEN ENCOUNTERING
MELTING CLOSE TO THE SURFACE. IT MAY BE THAT THE PCPN BEGINS AS
RAIN...BUT AS THE TEMPERATURES FALL WITH THE PCPN...TRANSITIONS TO
SNOW. FOR AREAS THAT DO GET SNOW...THERE IS THE QUESTION OF
ACCUMULATION BECAUSE THE TEMPERATURES IN THE LOW TO MID 30S MAY
MELT MUCH OF WHAT FALLS. I AM ONLY REASONABLY CONFIDENT THAT THE
ARROWHEAD WILL SEE ANY SIGNIFICANT ACCUMULATION...PERHAPS UP TO 2
INCHES...DUE TO THE LOWER TEMPERATURES. I INCREASED THE SNOWFALL
FORECAST ACROSS THE REST OF THE NORTHLAND TOO...BUT GENERALLY GAVE
A HALF INCH OR LESS OF ACCUMULATION. WE WILL NEED TO MONITOR THE
PCPN OVER THE NEXT FEW HOURS AND SEE HOW QUICKLY THE PCPN
TRANSITIONS TO SNOW. IT MAY BE SOME AREAS GET A SURPRISE 1 OR 2
INCHES OF SNOW. THE COLD FRONT...CURRENTLY IN THE EASTERN
DAKOTAS...WILL MOVE THROUGH THE NORTHLAND THIS EVENING. THERE
SHOULD BE SOME PARTIAL CLEARING ACROSS THE FORECAST AREA IN THE
WAKE OF THE FRONT LATE TONIGHT. OVERNIGHT LOWS WILL RANGE FROM THE
MID 30S ACROSS THE FAR SE FORECAST AREA TO THE MID TO UPPER 20S
ACROSS THE WEST AND NORTH.
MONDAY...THE COLD FRONT WILL STALL FROM IOWA TO UPPER PENINSULA
MICHIGAN AS A LOW PRESSURE CENTER BEGINS TO DEVELOP ALONG THE
FRONT IN THE MISSOURI AREA. THE MODELS CONTINUE TO INDICATE PCPN
ON THE WESTERN SIDE OF THE FRONT WILL BEGIN TO SPREAD FROM EASTERN
SOUTH DAKOTA AND SOUTHERN MINNESOTA INTO NE MINNESOTA AND NW
WISCONSIN DURING THE AFTERNOON. THE MODELS AND SOUNDINGS SEEM TO
FAVOR SNOW...BUT THE SURFACE TEMPERATURES IN THE UPPER 30S TO MID
40S WILL PROBABLY RESULT IN SOME MELTING TO RAIN DURING THE
AFTERNOON...ESPECIALLY FOR NW WISCONSIN. HOWEVER...THIS WILL BE
ANOTHER TRICKY SITUATION THAT WILL NEED TO BE LOOKED INTO MORE
BECAUSE IT COULD JUST AS EASILY MEAN IN UP TO A FEW INCHES OF SNOW
ACCUMULATION FOR SOME PARTS OF THE FORECAST AREA DURING THE
AFTERNOON. THE PCPN WILL LIKELY THAN TRANSITION TO SNOW MONDAY
EVENING.
LONG TERM.../MONDAY NIGHT - SATURDAY/
SNOW WILL LIKELY BE ONGOING AT THE START OF THE PERIOD...AS
FAVORABLE JET DYNAMICS COME INTO PLAY ACROSS THE NORTHLAND. STRONG
ASCENT IN THE RIGHT ENTRANCE REGION OF THE 115 KNOT JET SEGMENT
MOVING ACROSS MN AND INTO ONTARIO WILL AID IN PROVIDING PLENTY OF
FORCING FOR WIDESPREAD PRECIPITATION ACROSS PORTIONS OF MN AND WI.
THE MODELS GENERALLY SHOW A GREAT DEAL OF UPPER LEVEL DIVERGENCE AS
ANOTHER STRONG JET SEGMENT ALSO LIFTS INTO THE WESTERN GREAT LAKES
FROM THE PLAINS. THE NAM...GFS AND ECMWF ALL SHOW A STRONG
BAROCLINIC ZONE ACROSS SE MN AND MUCH OF THE NW 1/2 OF WI...ALONG
WITH A STRONG LLJ OF 30-40 KT. COULD BE A FEW INCHES OF SNOW ACROSS
NE MN AND SEVERAL INCHES OF SNOW ACROSS NW WI. A DISTINCT WARMING
TREND WILL THEN TAKE PLACE ACROSS THE REGION...ALTHOUGH IT WILL BE A
BIT UNSETTLED FOR THE REMAINDER OF THE EXTENDED AS A FEW LOW
PRESSURE SYSTEMS WILL MOVE THROUGH THE REGION.
&&
.POINT TEMPS/POPS...
DLH 30 41 26 41 / 100 50 60 20
INL 26 39 20 39 / 100 0 10 10
BRD 29 40 24 41 / 60 40 20 10
HYR 34 46 28 42 / 100 60 80 30
ASX 33 45 31 41 / 100 40 80 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...MELDE
AREA FORECAST DISCUSSION
NWS DULUTH MN
642 PM CDT SUN APR 21 2013
.UPDATE...
RAIN AND SNOW WAS OCCURRING OVER A GOOD PORTION OF THE EASTERN
HALF OF MINNESOTA INTO WESTERN WISCONSIN THIS EVENING. SNOW WAS
DOMINANT ACROSS THE FAR NORTHERN PORTION OF OUR CWA...AND WAS
OCCURRING AT KDLH. THE RAP AND NAM BOTH INDICATE WET BULB ZERO
LEVELS SHOULD HAVE INCREASED QUITE A BIT BETWEEN 21Z AND 00Z
OVER THE SOUTHERN HALF OF THE CWA. HOWEVER...KDLH REMAINS MOSTLY
SNOW BUT WE DO EXPECT A MIX TO OCCUR AS PRECIP RATES DIMINISH. WE
ADJUSTED PRECIP TYPE/POPS A BIT EARLIER THIS EVENING...AND WILL DO
SO AS THE PRECIP DIMINISHES FROM WEST TO EAST OVERNIGHT.
&&
.AVIATION...00Z TAFS
IFR OR MVFR CONDITIONS COVERED THE NORTHLAND THIS EVENING...AND
THAT IS EXPECTED TO CONTINUE OVERNIGHT. AN AREA OF SNOW/RAIN
COVERED MOST OF NORTHEAST MINNESOTA AND NORTHWEST WISCONSIN...WITH
RADAR SHOWING THE PRECIPITATION DIMINISHING FROM WEST TO EAST. THAT
TREND WILL CONTINUE OVERNIGHT...WITH MOST OF THE PRECIPITATION
EXITING EASTERN MINNESOTA BETWEEN 03-06Z...AND NORTHWEST
WISCONSIN BETWEEN 05-08Z. IFR OR MVFR CONDITIONS WILL REMAIN...AND
WE EXPECT IMPROVEMENT MONDAY MORNING...BEFORE YET ANOTHER SYSTEM
WILL BRING LOWER CEILINGS AND MORE SNOW TO THE NORTHLAND. THE BEST
CHANCE FOR ADDITIONAL SNOW WILL BE OVER EAST CENTRAL MINNESOTA AND
NORTHWEST WISCONSIN OVER OUR CWA.
&&
.PREV DISCUSSION... /ISSUED 306 PM CDT SUN APR 21 2013/
SHORT TERM.../NOW - MONDAY/
THROUGH TONIGHT...THE FOCUS FOR THIS FORECAST IS THE PCPN
ASSOCIATED WITH AN APPROACHING COLD FRONT THAT IS ALREADY MOVING
INTO THE WESTERN FORECAST AREA. THE NORTHLAND IS EXPECTED TO HAVE
THIS PCPN MOVE THROUGH THE REGION FROM WEST TO EAST THROUGH
TONIGHT. WHILE ARE MOSTLY FORECASTING RAIN WITH LITTLE TO NO SNOW
ACCUMULATION...THERE IS STILL SOME UNCERTAINTY AS TO PCPN TYPE AND
SNOWFALL ACCUMULATION SINCE THE TEMPERATURES ACROSS THE NORTHLAND
ARE ONLY IN THE MID TO UPPER 30S. BASED ON MODEL SOUNDINGS...THE
SNOW IS DEFINITELY FALLING AS SNOW ALOFT...BUT THEN ENCOUNTERING
MELTING CLOSE TO THE SURFACE. IT MAY BE THAT THE PCPN BEGINS AS
RAIN...BUT AS THE TEMPERATURES FALL WITH THE PCPN...TRANSITIONS TO
SNOW. FOR AREAS THAT DO GET SNOW...THERE IS THE QUESTION OF
ACCUMULATION BECAUSE THE TEMPERATURES IN THE LOW TO MID 30S MAY
MELT MUCH OF WHAT FALLS. I AM ONLY REASONABLY CONFIDENT THAT THE
ARROWHEAD WILL SEE ANY SIGNIFICANT ACCUMULATION...PERHAPS UP TO 2
INCHES...DUE TO THE LOWER TEMPERATURES. I INCREASED THE SNOWFALL
FORECAST ACROSS THE REST OF THE NORTHLAND TOO...BUT GENERALLY GAVE
A HALF INCH OR LESS OF ACCUMULATION. WE WILL NEED TO MONITOR THE
PCPN OVER THE NEXT FEW HOURS AND SEE HOW QUICKLY THE PCPN
TRANSITIONS TO SNOW. IT MAY BE SOME AREAS GET A SURPRISE 1 OR 2
INCHES OF SNOW. THE COLD FRONT...CURRENTLY IN THE EASTERN
DAKOTAS...WILL MOVE THROUGH THE NORTHLAND THIS EVENING. THERE
SHOULD BE SOME PARTIAL CLEARING ACROSS THE FORECAST AREA IN THE
WAKE OF THE FRONT LATE TONIGHT. OVERNIGHT LOWS WILL RANGE FROM THE
MID 30S ACROSS THE FAR SE FORECAST AREA TO THE MID TO UPPER 20S
ACROSS THE WEST AND NORTH.
MONDAY...THE COLD FRONT WILL STALL FROM IOWA TO UPPER PENINSULA
MICHIGAN AS A LOW PRESSURE CENTER BEGINS TO DEVELOP ALONG THE
FRONT IN THE MISSOURI AREA. THE MODELS CONTINUE TO INDICATE PCPN
ON THE WESTERN SIDE OF THE FRONT WILL BEGIN TO SPREAD FROM EASTERN
SOUTH DAKOTA AND SOUTHERN MINNESOTA INTO NE MINNESOTA AND NW
WISCONSIN DURING THE AFTERNOON. THE MODELS AND SOUNDINGS SEEM TO
FAVOR SNOW...BUT THE SURFACE TEMPERATURES IN THE UPPER 30S TO MID
40S WILL PROBABLY RESULT IN SOME MELTING TO RAIN DURING THE
AFTERNOON...ESPECIALLY FOR NW WISCONSIN. HOWEVER...THIS WILL BE
ANOTHER TRICKY SITUATION THAT WILL NEED TO BE LOOKED INTO MORE
BECAUSE IT COULD JUST AS EASILY MEAN IN UP TO A FEW INCHES OF SNOW
ACCUMULATION FOR SOME PARTS OF THE FORECAST AREA DURING THE
AFTERNOON. THE PCPN WILL LIKELY THAN TRANSITION TO SNOW MONDAY
EVENING.
LONG TERM.../MONDAY NIGHT - SATURDAY/
SNOW WILL LIKELY BE ONGOING AT THE START OF THE PERIOD...AS
FAVORABLE JET DYNAMICS COME INTO PLAY ACROSS THE NORTHLAND. STRONG
ASCENT IN THE RIGHT ENTRANCE REGION OF THE 115 KNOT JET SEGMENT
MOVING ACROSS MN AND INTO ONTARIO WILL AID IN PROVIDING PLENTY OF
FORCING FOR WIDESPREAD PRECIPITATION ACROSS PORTIONS OF MN AND WI.
THE MODELS GENERALLY SHOW A GREAT DEAL OF UPPER LEVEL DIVERGENCE AS
ANOTHER STRONG JET SEGMENT ALSO LIFTS INTO THE WESTERN GREAT LAKES
FROM THE PLAINS. THE NAM...GFS AND ECMWF ALL SHOW A STRONG
BAROCLINIC ZONE ACROSS SE MN AND MUCH OF THE NW 1/2 OF WI...ALONG
WITH A STRONG LLJ OF 30-40 KT. COULD BE A FEW INCHES OF SNOW ACROSS
NE MN AND SEVERAL INCHES OF SNOW ACROSS NW WI. A DISTINCT WARMING
TREND WILL THEN TAKE PLACE ACROSS THE REGION...ALTHOUGH IT WILL BE A
BIT UNSETTLED FOR THE REMAINDER OF THE EXTENDED AS A FEW LOW
PRESSURE SYSTEMS WILL MOVE THROUGH THE REGION.
&&
.POINT TEMPS/POPS...
DLH 30 41 26 41 / 100 50 60 20
INL 26 39 20 39 / 100 0 10 10
BRD 29 40 24 41 / 60 40 20 10
HYR 34 46 28 42 / 100 60 80 30
ASX 33 45 31 41 / 90 40 80 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...MELDE
AVIATION.....MELDE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
118 PM CDT SAT APR 20 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 335 AM CDT SAT APR 20 2013
THERE ARE A FEW FORECAST ISSUES OF CONCERN OVER THE NEXT SEVERAL
DAYS... AND THE S-WORD IS INVOLVED YET AGAIN. IN THE BIG
PICTURE... WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES CONTINUE
TO SHOW AN ALL TOO FAMILIAR PATTERN OF RIDGING OFF THE WEST COAST
WITH NORTHWEST UPPER FLOW INTO OUR AREA. THE UPPER TROUGH
ASSOCIATED WITH OUR RECENT STORM HAS PUSHED EAST INTO THE GREAT
LAKES... AND WE NOW AWAIT THE ARRIVAL OF SHORTWAVE ENERGY DROPPING
SOUTHEAST INTO ALBERTA AND ANOTHER SHORTWAVE NEAR THE NEVADA/UTAH
BORDER. THE SOUTHERN FEATURE WON/T DIRECTLY EFFECT US... ALTHOUGH
IT WILL HELP IN PUSHING THE ELEVATED WARM FRONT THROUGH THE AREA
LATE TONIGHT AND SUNDAY. THE NORTHERN WAVE WILL PASS BY TO OUR
NORTH... BUT WILL STILL MANAGE TO DRAG A COLD FRONT BACK THROUGH
THE AREA SUNDAY NIGHT. A SHORTWAVE FARTHER UPSTREAM OVER ALASKA
WILL DROP INTO THE MEAN TROUGH SUNDAY INTO MONDAY AND MAKE THE
TURN TO OUR SOUTH... LIFTING NORTHEAST THROUGH THE REGION LATE
MONDAY INTO TUESDAY. THE GFS AND ECMWF HAVE COME INTO DECENT
AGREEMENT IN THEIR HANDLING OF THIS FEATURE... ALTHOUGH THE ECMWF
IS A BIT FARTHER WEST IN ITS PLACEMENT OF THE INVERTED TROUGH AND
EVENTUAL SURFACE LOW TRACK... AND HAS THE RAIN/SNOW LINE A BIT
FARTHER WEST AS A RESULT. FOR NOW... A COMPROMISE BETWEEN THE GFS
AND ECMWF SEEMS TO BE THE MOST LOGICAL COURSE OF ACTION...
ESPECIALLY GIVEN THE ECMWF SHIFTED TOWARD THE GFS SOLUTION WITH
ITS MOST RECENT RUN.
LOOK FOR THE SURFACE RIDGE TO DRIFT EAST ACROSS THE AREA TODAY...
WITH SOME INCREASE IN MID-HIGH CLOUDS THROUGH THE DAY AS WE GET
INTO RETURN FLOW AND SEE A BIT OF AN UPPER LEVEL RIDGE WORK ACROSS
THE AREA. WARM ADVECTION PCPN SHOULD GET GOING TO OUR SOUTHWEST
LATE THIS AFTERNOON AND SPREAD EAST ACROSS THE AREA TONIGHT. THE
290-295K ISENTROPIC LAYER OFF THE NAM AND GFS DOES A NICE JOB OF
HIGHLIGHTING THE TIMING OF THINGS AND SUGGESTING WHERE THE BEST
PCPN SHOULD OCCUR. FORECAST SOUNDINGS ARE GENERALLY SUPPORTIVE OF
SNOW... AT LEAST INITIALLY... BEFORE WE SEE A BIT OF A WARM FRONT
LIFT THROUGH SUNDAY MORNING AND CHANGE ANY LINGERING PCPN OVER TO
RAIN. BEFORE THAT OCCURS THERE COULD BE SOME LIGHT
ACCUMULATIONS... ALTHOUGH WOULDN/T EXPECT MUCH MORE THAN AN INCH
WITH PCPN TOTALS GENERALLY MAXING OUT FROM ONE TO TWO TENTHS OF AN
INCH. AS THE SHORTWAVE MOVES BY TO OUR NORTH TONIGHT WE WILL SEE A
COLD FRONT MOVE THROUGH THE AREA. EXACTLY HOW FAR THAT BOUNDARY
GETS DRAGGED SOUTHEAST WILL DICTATE WHERE THE BAROCLINIC ZONE...
AND EVENTUALLY SURFACE LOW TRACK... WILL SETUP FOR THE MONDAY STORM
SYSTEM.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 335 AM CDT SAT APR 20 2013
THE NAM APPEARS TOO FAR EAST... MUCH LIKE WITH THE LAST
SYSTEM... WHILE THE ECMWF IS THE WESTERNMOST OF THE DETERMINISTIC
SOLUTIONS. THE SREF MEAN IS EAST OF THE NAM AND WILL BE DISCOUNTED
AT THIS POINT. ALL IN ALL... A BLEND OF THE GFS AND ECMWF LOOKS TO
BE THE BEST GUESS AT THIS POINT... WHICH MEANS WE WILL ONCE AGAIN
BE DEALING WITH A DECENT PCPN EVENT ACROSS THE AREA WITH MANY
LOCATIONS LIKELY SEEING THINGS OCCUR IN THE FORM OF SNOW.
FRONTOGENESIS IN THE 700-800MB LAYER REALLY GETS GOING MONDAY
AFTERNOON... WITH WEAKLY STABLE AIR IN THE ZONE OF BEST FORCING...
SO EXPECT TO SEE GOOD UPWARD MOTION IN ASSOCIATION WITH THE LOW-
MID LEVEL DEFORMATION AND FRONTOGENESIS. THE GFS AND ECMWF BOTH
MANAGE TO SQUEEZE OUT 0.5-0.75 INCHES OR SO OF PCPN... SO THERE IS
DEFINITELY THE POTENTIAL FOR SEVERAL INCHES OF SNOW AND PERHAPS A
BIT MORE DEPENDING ON WHERE THE RAIN/SNOW LINE SETS UP WITH
RESPECT TO THE HEAVIEST PCPN. INCLUDED SOME 2 TO 5 INCH AMOUNTS IN
THE FORECAST GRIDS... WITH A RAIN/SNOW LINE SIMILAR TO THE LAST
EVENT... BUT CERTAINLY DON/T HAVE HIGH CONFIDENCE AT THIS POINT.
SOME LIGHT PCPN COULD LINGER INTO TUESDAY ACROSS THE EAST... BUT
ANY ADDITIONAL PCPN AMOUNTS SHOULD BE LIGHT. HIGH PRESSURE WILL
THEN BUILD INTO THE AREA THROUGH WEDNESDAY... WITH SOME PERIODIC
PCPN CHANCES RETURNING TO THE REGION FOR THE LATTER HALF OF THE
WEEK AS A FEW QUICKLY MOVING SHORTWAVES EMBEDDED IN THE
WEST/NORTHWEST FLOW ROTATE THROUGH THE AREA. PCPN-TYPE WITH EACH
SYSTEM WILL DEPEND TO SOME EXTENT ON THE TIME OF DAY... SINCE
TEMPERATURES ALOFT WILL BE SUFFICIENTLY COLD FOR SNOW UNTIL
FRIDAY... BUT BOUNDARY LAYER TEMPERATURES DURING THE DAYTIME
SHOULD KEEP THINGS RAIN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1258 PM CDT SAT APR 20 2013
VFR EXPECTED FOR THE FIRST 9-12 HOURS OF THE TAF. MODERATE SNOW
CURRENTLY IN SD WILL MOVE EAST WITH TIME AND EVENTUALLY PRODUCE
MVFR TO IFR CONDITIONS IN MN FROM 04-09Z TONIGHT. SNOW PERIOD
SHOULD BE RELATIVELY BRIEF...FOLLOWED BY A LULL...AND THEN
DETERIORATING CONDITIONS AND A LIGHT TO MODERATE BAND OF RAIN
DURING THE DAY ON SUNDAY.
KMSP...
NO PROBLEMS THROUGH THE REMAINDER OF THE DAY TODAY. LOOK FOR A 2-3
HOUR WINDOW FOR LIGHT SNOW LATE TONIGHT. MVFR CONDITIONS POSSIBLE
WITH VERY MINOR SNOW ACCUMULATION. RAIN AND MVFR/IFR IS EXPECTED
ON SUNDAY...THERE WILL BE A LONGER PERIOD OF RAIN...PERHAPS 3-6
HOURS.
/OUTLOOK FOR KMSP/
SUN NGT...MVFR WITH -RA/-SN PSBL. WIND BCMG NW 5 TO 10 KTS.
MON...MVFR WITH -SN. IFR CIGS PSBL. NW WIND 15-20 KTS.
TUE...VFR. NW WIND 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...WRB
LONG TERM...TRH
AVIATION...CLF
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
654 AM CDT SAT APR 20 2013
.DISCUSSION...
THERE ARE A FEW FORECAST ISSUES OF CONCERN OVER THE NEXT SEVERAL
DAYS... AND THE S-WORD IS INVOLVED YET AGAIN. IN THE BIG
PICTURE... WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES CONTINUE
TO SHOW AN ALL TOO FAMILIAR PATTERN OF RIDGING OFF THE WEST COAST
WITH NORTHWEST UPPER FLOW INTO OUR AREA. THE UPPER TROUGH
ASSOCIATED WITH OUR RECENT STORM HAS PUSHED EAST INTO THE GREAT
LAKES... AND WE NOW AWAIT THE ARRIVAL OF SHORTWAVE ENERGY DROPPING
SOUTHEAST INTO ALBERTA AND ANOTHER SHORTWAVE NEAR THE NEVADA/UTAH
BORDER. THE SOUTHERN FEATURE WON/T DIRECTLY EFFECT US... ALTHOUGH
IT WILL HELP IN PUSHING THE ELEVATED WARM FRONT THROUGH THE AREA
LATE TONIGHT AND SUNDAY. THE NORTHERN WAVE WILL PASS BY TO OUR
NORTH... BUT WILL STILL MANAGE TO DRAG A COLD FRONT BACK THROUGH
THE AREA SUNDAY NIGHT. A SHORTWAVE FARTHER UPSTREAM OVER ALASKA
WILL DROP INTO THE MEAN TROUGH SUNDAY INTO MONDAY AND MAKE THE
TURN TO OUR SOUTH... LIFTING NORTHEAST THROUGH THE REGION LATE
MONDAY INTO TUESDAY. THE GFS AND ECMWF HAVE COME INTO DECENT
AGREEMENT IN THEIR HANDLING OF THIS FEATURE... ALTHOUGH THE ECMWF
IS A BIT FARTHER WEST IN ITS PLACEMENT OF THE INVERTED TROUGH AND
EVENTUAL SURFACE LOW TRACK... AND HAS THE RAIN/SNOW LINE A BIT
FARTHER WEST AS A RESULT. FOR NOW... A COMPROMISE BETWEEN THE GFS
AND ECMWF SEEMS TO BE THE MOST LOGICAL COURSE OF ACTION...
ESPECIALLY GIVEN THE ECMWF SHIFTED TOWARD THE GFS SOLUTION WITH
ITS MOST RECENT RUN.
LOOK FOR THE SURFACE RIDGE TO DRIFT EAST ACROSS THE AREA TODAY...
WITH SOME INCREASE IN MID-HIGH CLOUDS THROUGH THE DAY AS WE GET
INTO RETURN FLOW AND SEE A BIT OF AN UPPER LEVEL RIDGE WORK ACROSS
THE AREA. WARM ADVECTION PCPN SHOULD GET GOING TO OUR SOUTHWEST
LATE THIS AFTERNOON AND SPREAD EAST ACROSS THE AREA TONIGHT. THE
290-295K ISENTROPIC LAYER OFF THE NAM AND GFS DOES A NICE JOB OF
HIGHLIGHTING THE TIMING OF THINGS AND SUGGESTING WHERE THE BEST
PCPN SHOULD OCCUR. FORECAST SOUNDINGS ARE GENERALLY SUPPORTIVE OF
SNOW... AT LEAST INITIALLY... BEFORE WE SEE A BIT OF A WARM FRONT
LIFT THROUGH SUNDAY MORNING AND CHANGE ANY LINGERING PCPN OVER TO
RAIN. BEFORE THAT OCCURS THERE COULD BE SOME LIGHT
ACCUMULATIONS... ALTHOUGH WOULDN/T EXPECT MUCH MORE THAN AN INCH
WITH PCPN TOTALS GENERALLY MAXING OUT FROM ONE TO TWO TENTHS OF AN
INCH. AS THE SHORTWAVE MOVES BY TO OUR NORTH TONIGHT WE WILL SEE A
COLD FRONT MOVE THROUGH THE AREA. EXACTLY HOW FAR THAT BOUNDARY
GETS DRAGGED SOUTHEAST WILL DICTATE WHERE THE BAROCLINIC ZONE...
AND EVENTUALLY SURFACE LOW TRACK... WILL SETUP FOR THE MONDAY STORM
SYSTEM. THE NAM APPEARS TOO FAR EAST... MUCH LIKE WITH THE LAST
SYSTEM... WHILE THE ECMWF IS THE WESTERNMOST OF THE DETERMINISTIC
SOLUTIONS. THE SREF MEAN IS EAST OF THE NAM AND WILL BE DISCOUNTED
AT THIS POINT. ALL IN ALL... A BLEND OF THE GFS AND ECMWF LOOKS TO
BE THE BEST GUESS AT THIS POINT... WHICH MEANS WE WILL ONCE AGAIN
BE DEALING WITH A DECENT PCPN EVENT ACROSS THE AREA WITH MANY
LOCATIONS LIKELY SEEING THINGS OCCUR IN THE FORM OF SNOW.
FRONTOGENESIS IN THE 700-800MB LAYER REALLY GETS GOING MONDAY
AFTERNOON... WITH WEAKLY STABLE AIR IN THE ZONE OF BEST FORCING...
SO EXPECT TO SEE GOOD UPWARD MOTION IN ASSOCIATION WITH THE LOW-
MID LEVEL DEFORMATION AND FRONTOGENESIS. THE GFS AND ECMWF BOTH
MANAGE TO SQUEEZE OUT 0.5-0.75 INCHES OR SO OF PCPN... SO THERE IS
DEFINITELY THE POTENTIAL FOR SEVERAL INCHES OF SNOW AND PERHAPS A
BIT MORE DEPENDING ON WHERE THE RAIN/SNOW LINE SETS UP WITH
RESPECT TO THE HEAVIEST PCPN. INCLUDED SOME 2 TO 5 INCH AMOUNTS IN
THE FORECAST GRIDS... WITH A RAIN/SNOW LINE SIMILAR TO THE LAST
EVENT... BUT CERTAINLY DON/T HAVE HIGH CONFIDENCE AT THIS POINT.
SOME LIGHT PCPN COULD LINGER INTO TUESDAY ACROSS THE EAST... BUT
ANY ADDITIONAL PCPN AMOUNTS SHOULD BE LIGHT. HIGH PRESSURE WILL
THEN BUILD INTO THE AREA THROUGH WEDNESDAY... WITH SOME PERIODIC
PCPN CHANCES RETURNING TO THE REGION FOR THE LATTER HALF OF THE
WEEK AS A FEW QUICKLY MOVING SHORTWAVES EMBEDDED IN THE
WEST/NORTHWEST FLOW ROTATE THROUGH THE AREA. PCPN-TYPE WITH EACH
SYSTEM WILL DEPEND TO SOME EXTENT ON THE TIME OF DAY... SINCE
TEMPERATURES ALOFT WILL BE SUFFICIENTLY COLD FOR SNOW UNTIL
FRIDAY... BUT BOUNDARY LAYER TEMPERATURES DURING THE DAYTIME
SHOULD KEEP THINGS RAIN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 643 AM CDT SAT APR 20 2013
A RIDGE AXIS WILL SLIDE OVER THE CWA TODAY PROVIDING CLEAR SKIES
AND LIGHT WINDS. AS THE RIDGE PUSHES EAST...LGT/VAR WINDS WILL
BECOME SOUTHEAST AND STRENGTHEN THIS EVENING. A WARM FRONT WILL
BRING A BAND OF SNOW ACROSS THE REGION TONIGHT WITH MVFR VIS
EXPECTED. CIGS ARE MORE QUESTIONABLE DUE TO LOW LEVEL DRY
AIR...HOVERING AROUND THE 3KFT LEVEL.
KMSP...VFR UNTIL LATE TONIGHT WITH THE ARRIVAL OF THE SNOW.
THEREAFTER...MVFR CONDITIONS EXPECTED.
/OUTLOOK FOR KMSP/
SUN AFTN...MVFR WITH -RA. IFR CIGS PSBL. SSE WIND 10-15 KTS.
SUN NGT...MVFR WITH -RA/-SN PSBL. WIND BCMG NW 5 TO 10 KTS.
MON...MVFR WITH -SN. IFR CIGS PSBL. NW WIND 15-20 KTS.
TUE...VFR. NW WIND 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
DISCUSSION...TRH
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
335 AM CDT SAT APR 20 2013
.DISCUSSION...
THERE ARE A FEW FORECAST ISSUES OF CONCERN OVER THE NEXT SEVERAL
DAYS... AND THE S-WORD IS INVOLVED YET AGAIN. IN THE BIG
PICTURE... WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES CONTINUE
TO SHOW AN ALL TOO FAMILIAR PATTERN OF RIDGING OFF THE WEST COAST
WITH NORTHWEST UPPER FLOW INTO OUR AREA. THE UPPER TROUGH
ASSOCIATED WITH OUR RECENT STORM HAS PUSHED EAST INTO THE GREAT
LAKES... AND WE NOW AWAIT THE ARRIVAL OF SHORTWAVE ENERGY DROPPING
SOUTHEAST INTO ALBERTA AND ANOTHER SHORTWAVE NEAR THE NEVADA/UTAH
BORDER. THE SOUTHERN FEATURE WON/T DIRECTLY EFFECT US... ALTHOUGH
IT WILL HELP IN PUSHING THE ELEVATED WARM FRONT THROUGH THE AREA
LATE TONIGHT AND SUNDAY. THE NORTHERN WAVE WILL PASS BY TO OUR
NORTH... BUT WILL STILL MANAGE TO DRAG A COLD FRONT BACK THROUGH
THE AREA SUNDAY NIGHT. A SHORTWAVE FARTHER UPSTREAM OVER ALASKA
WILL DROP INTO THE MEAN TROUGH SUNDAY INTO MONDAY AND MAKE THE
TURN TO OUR SOUTH... LIFTING NORTHEAST THROUGH THE REGION LATE
MONDAY INTO TUESDAY. THE GFS AND ECMWF HAVE COME INTO DECENT
AGREEMENT IN THEIR HANDLING OF THIS FEATURE... ALTHOUGH THE ECMWF
IS A BIT FARTHER WEST IN ITS PLACEMENT OF THE INVERTED TROUGH AND
EVENTUAL SURFACE LOW TRACK... AND HAS THE RAIN/SNOW LINE A BIT
FARTHER WEST AS A RESULT. FOR NOW... A COMPROMISE BETWEEN THE GFS
AND ECMWF SEEMS TO BE THE MOST LOGICAL COURSE OF ACTION...
ESPECIALLY GIVEN THE ECMWF SHIFTED TOWARD THE GFS SOLUTION WITH
ITS MOST RECENT RUN.
LOOK FOR THE SURFACE RIDGE TO DRIFT EAST ACROSS THE AREA TODAY...
WITH SOME INCREASE IN MID-HIGH CLOUDS THROUGH THE DAY AS WE GET
INTO RETURN FLOW AND SEE A BIT OF AN UPPER LEVEL RIDGE WORK ACROSS
THE AREA. WARM ADVECTION PCPN SHOULD GET GOING TO OUR SOUTHWEST
LATE THIS AFTERNOON AND SPREAD EAST ACROSS THE AREA TONIGHT. THE
290-295K ISENTROPIC LAYER OFF THE NAM AND GFS DOES A NICE JOB OF
HIGHLIGHTING THE TIMING OF THINGS AND SUGGESTING WHERE THE BEST
PCPN SHOULD OCCUR. FORECAST SOUNDINGS ARE GENERALLY SUPPORTIVE OF
SNOW... AT LEAST INITIALLY... BEFORE WE SEE A BIT OF A WARM FRONT
LIFT THROUGH SUNDAY MORNING AND CHANGE ANY LINGERING PCPN OVER TO
RAIN. BEFORE THAT OCCURS THERE COULD BE SOME LIGHT
ACCUMULATIONS... ALTHOUGH WOULDN/T EXPECT MUCH MORE THAN AN INCH
WITH PCPN TOTALS GENERALLY MAXING OUT FROM ONE TO TWO TENTHS OF AN
INCH. AS THE SHORTWAVE MOVES BY TO OUR NORTH TONIGHT WE WILL SEE A
COLD FRONT MOVE THROUGH THE AREA. EXACTLY HOW FAR THAT BOUNDARY
GETS DRAGGED SOUTHEAST WILL DICTATE WHERE THE BAROCLINIC ZONE...
AND EVENTUALLY SURFACE LOW TRACK... WILL SETUP FOR THE MONDAY STORM
SYSTEM. THE NAM APPEARS TOO FAR EAST... MUCH LIKE WITH THE LAST
SYSTEM... WHILE THE ECMWF IS THE WESTERNMOST OF THE DETERMINISTIC
SOLUTIONS. THE SREF MEAN IS EAST OF THE NAM AND WILL BE DISCOUNTED
AT THIS POINT. ALL IN ALL... A BLEND OF THE GFS AND ECMWF LOOKS TO
BE THE BEST GUESS AT THIS POINT... WHICH MEANS WE WILL ONCE AGAIN
BE DEALING WITH A DECENT PCPN EVENT ACROSS THE AREA WITH MANY
LOCATIONS LIKELY SEEING THINGS OCCUR IN THE FORM OF SNOW.
FRONTOGENESIS IN THE 700-800MB LAYER REALLY GETS GOING MONDAY
AFTERNOON... WITH WEAKLY STABLE AIR IN THE ZONE OF BEST FORCING...
SO EXPECT TO SEE GOOD UPWARD MOTION IN ASSOCIATION WITH THE LOW-
MID LEVEL DEFORMATION AND FRONTOGENESIS. THE GFS AND ECMWF BOTH
MANAGE TO SQUEEZE OUT 0.5-0.75 INCHES OR SO OF PCPN... SO THERE IS
DEFINITELY THE POTENTIAL FOR SEVERAL INCHES OF SNOW AND PERHAPS A
BIT MORE DEPENDING ON WHERE THE RAIN/SNOW LINE SETS UP WITH
RESPECT TO THE HEAVIEST PCPN. INCLUDED SOME 2 TO 5 INCH AMOUNTS IN
THE FORECAST GRIDS... WITH A RAIN/SNOW LINE SIMILAR TO THE LAST
EVENT... BUT CERTAINLY DON/T HAVE HIGH CONFIDENCE AT THIS POINT.
SOME LIGHT PCPN COULD LINGER INTO TUESDAY ACROSS THE EAST... BUT
ANY ADDITIONAL PCPN AMOUNTS SHOULD BE LIGHT. HIGH PRESSURE WILL
THEN BUILD INTO THE AREA THROUGH WEDNESDAY... WITH SOME PERIODIC
PCPN CHANCES RETURNING TO THE REGION FOR THE LATTER HALF OF THE
WEEK AS A FEW QUICKLY MOVING SHORTWAVES EMBEDDED IN THE
WEST/NORTHWEST FLOW ROTATE THROUGH THE AREA. PCPN-TYPE WITH EACH
SYSTEM WILL DEPEND TO SOME EXTENT ON THE TIME OF DAY... SINCE
TEMPERATURES ALOFT WILL BE SUFFICIENTLY COLD FOR SNOW UNTIL
FRIDAY... BUT BOUNDARY LAYER TEMPERATURES DURING THE DAYTIME
SHOULD KEEP THINGS RAIN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1145 PM CDT FRI APR 19 2013
A RIDGE OF HIGH PRESSURE OVER THE NORTHERN PLAINS WILL MOVE
ACROSS THE TAF SITES ON SATURDAY. LIGHT NW WINDS OVERNIGHT WILL
BECOME SE ON THE BACKSIDE OF THE HIGH SATURDAY AFTERNOON. THE MAIN
CONCERNS DURING THE TAF PERIOD ARE MVFR CEILINGS AND LIGHT SNOW
SPREADING ACROSS THE TAF SITES SATURDAY NIGHT AND EARLY SUNDAY FROM
WEST TO EAST. CONFIDENCE IS HIGH ON BOTH OCCURRING. FOR
NOW...STARTED MVFR/-SN IN THE KRWF AND KAXN TAFS IN THE 03Z/04Z
TIME FRAME RESPECTIVELY WITH THE ACTIVITY REACHING KMSP AROUND
21/08Z.
KMSP...NO PROBLEMS OVERNIGHT AND SATURDAY AS HIGH PRESSURE BUILDS
IN. NW WINDS THROUGH DAYBREAK UP TO 10 KNOTS THEN BECOMING MORE
330-350 AT 4-6 KNOTS DURING THE MORNING. THE WINDS WILL
TRANSITION TO SE (110-130) DURING THE AFTERNOON WITH SPEEDS
INCREASING TO 7-9 KNOTS BY EVENING. MVFR WITH -SN EXPECTED EARLY
SUNDAY MORNING.
/OUTLOOK FOR KMSP/
SUN AFTN...MVFR WITH -RA. IFR CIGS PSBL. SSE WIND 10-15 KTS.
SUN NGT...MVFR WITH -RA/-SN PSBL. WIND BCMG NW 5 TO 10 KTS.
MON...MVFR WITH -SN. IFR CIGS PSBL. NW WIND 15-20 KTS.
TUE...VFR. NW WIND 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DULUTH MN
1150 PM CDT FRI APR 19 2013
.UPDATE...
WE DROPPED THE WARNING FOR ASHLAND/IRON COUNTIES. RADAR/SATELLITE
AND THE MODELS ALL SHOW AN IMPROVING TREND. VSBY HAS RISEN AT
KIWD TO 10SM AS OF 1130 PM. DRIER AIR SHOULD CAUSE THE SNOW
SHOWERS TO BECOME LESS NUMEROUS AND DECREASE FURTHER IN INTENSITY.
WE ADDED SOME FOG TO NORTHWEST WISCONSIN AS KHYR AS BRIEFLY
DROPPED TO 0.75SM IN FOG.
&&
.AVIATION...06Z TAFS
MAINLY VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD. SOME MVFR OR
IFR CONDITIONS WILL REMAIN POSSIBLE THROUGH THE EARLY MORNING HOURS ALONG
THE SNOWBELT REGION OF ASHLAND AND IRON COUNTIES DUE TO LAKE
EFFECT SNOW/CLOUDS. SOME PATCHY FOG WILL ALSO BE POSSIBLE...AS
KHYR VSBY HAS DROPPED THIS EVENING.
NORTHWEST WINDS WILL GRADUALLY TURN SOUTHERLY ON SATURDAY. ANOTHER
DISTURBANCE WILL CAUSE MID TO HIGH CLOUDS TO THICKEN SATURDAY
AFTERNOON/EVENING...BUT ANY PRECIPITATION SHOULD HOLD OFF UNTIL
AFTER 06Z.
&&
.PREV DISCUSSION... /ISSUED 645 PM CDT FRI APR 19 2013/
UPDATE...
RADAR SHOWS COVERAGE OF THE SNOW SHOWERS WERE DIMINISHING ACROSS
THE ARROWHEAD AND EXTREME NORTHWEST WISCONSIN...AND VSBYS CONFIRM WITH
KCKC UP TO 1.5SM. WE MAY BE ABLE TO CANCEL THE WARNINGS IN THE
ARROWHEAD EARLY. GRAVITY WAVED INDUCED AREA OF SNOW SHOWERS ALSO
SEEMS TO BE DIMINISHING...AND A CROSS SECTION THROUGH THAT AREA
FROM THE RAP INDICATED CONDITIONS BECOMING LESS FAVORABLE AS DRIER
AIR MOVES IN. WE MAY ALSO DROP THE WARNING ACROSS DOUGLAS COUNTY
EARLY IF CURRENT TRENDS CONDITIONS.
STRONG WINDS AND A FAVORABLE SET UP FOR LAKE EFFECT SNOW WILL KEEP
SNOW SHOWERS GOING LONGER ACROSS PORTIONS OF BAYFIELD...BUT
ESPECIALLY ASHLAND AND IRON COUNTIES. STRONG WINDS WERE ALSO
CREATING ISSUES WITH BLOWING/DRIFTING.
WE EXPECT THE WINDS TO DIMINISH AS THE EVENING PROGRESSES.
AVIATION...00Z TAFS
CLOUDS WERE DIMINISHING THIS EVENING OVER MINNESOTA...WITH THE
SNOW SHOWERS ALSO DIMINISHING IN COVERAGE OVER NORTHEAST MINNESOTA
AND EXTREME NORTHWEST WISCONSIN. WE EXPECT THE TAF SITES TO BECOME
VFR THIS EVENING...WITH THE WIND DIMINISHING OVER THE NEXT 1-3
HOURS. MVFR TO LIFR CONDITIONS WILL CONTINUE THROUGH MOST OF THE
EVENING ACROSS THE SNOWBELT OF THE SOUTH SHORE.
VFR CONDITIONS WILL PREVAIL THROUGH THE DAY SATURDAY...WITH SOME
SCATTERED TO PERHAPS BROKEN CUMULUS DEVELOPING BY AFTERNOON.
PREV DISCUSSION... /ISSUED 347 PM CDT FRI APR 19 2013/
SHORT TERM...TONIGHT THROUGH SATURDAY...
THE POWERFUL WINTER STORM THAT BROUGHT 1 TO 2 FEET OF SNOW TO MUCH
OF THE NORTHLAND OVER THE LAST 1-2 DAYS WILL CONTINUE TO GRADUALLY
WIND DOWN ACROSS THE REGION OVERNIGHT. HEAVY SNOW CONTINUED ACROSS
THE ARROWHEAD...AND LOCALLY ACROSS THE SOUTH SHORE OF LAKE
SUPERIOR. COOK COUNTY CONTINUES TO HAVE A TOUGH TIME KEEPING ROADS
CLEARED WITH HEAVY SNOW AND INTENSE WINDS OF 40 TO 50 MPH AT
TIMES. IT APPEARS THE STANDING WAVE SHOWING UP ON 88D RADAR
EXTENDS NORTHWARD INTO COOK COUNTY WITH VISIBILITIES OF A QUARTER
MILE OR LESS AT TIMES. ACROSS THE SOUTH SHORE...LOCALLY HEAVY SNOW
SHOWERS CONTINUED ACROSS THAT AREA AS WELL. LOOKING FOR ANOTHER
GOOD 1 TO 3 INCHES IN THE ARROWHEAD AND LOCALLY UP TO ANOTHER 6
INCHES FOR THE SOUTH SHORE OF LAKE SUPERIOR.
HIGH PRESSURE WILL BUILD EASTWARD ACROSS THE NORTHLAND
OVERNIGHT...BRINGING A GRADUAL END TO THE SNOW FROM WEST TO EAST.
SOME CLEARING HAD ALREADY TAKEN PLACE IN THE WESTERN PORTION OF
THE CWA. THIS CLEARING WILL SET THE STAGE FOR SOME POTENTIALLY
RECORD BREAKING COLD TEMPERATURES BY SATURDAY MORNING. LOWS SHOULD
RANGE FROM THE SINGLE DIGITS TO THE TEENS DUE TO CLEARING
SKIES...DRIER AIR AND A SOLID SNOW PACK THAT IS QUITE UNUSUAL FOR
THIS TIME OF YEAR.
THERE SHOULD BE PLENTY OF SUNSHINE ON SATURDAY WITH TEMPERATURES
IN THE 30S FOR DAYTIME HIGHS...WELL BELOW OUR NORMAL HIGH AROUND
THE 50 DEGREE MARK.
LONG TERM...SATURDAY NIGHT THROUGH FRIDAY...
THE NEXT STORM SYSTEM WILL BE AFFECTING THE FORECAST AREA. THE
MODELS ARE DIFFERENT IN THEIR SOLUTIONS WITH THE MOVEMENT OF THE
LOW PRESSURE CENTER. THE NAM AND GFS HAS THE CENTER IN SOUTHERN
CANADA WITH A TROUGH ACROSS THE FORECAST AREA. THE ECMWF AND GEM
HAS THE CENTER MOVING ACROSS THE BORDER. PRECIP MOVES INTO THE
SOUTHERN PORTIONS OF THE FORECAST AREA SUNDAY MORNING AND SPREADS
NORTH. THE PTYPE WILL BE SNOW THIS MORNING AND SWITCH OVER TO RAIN
BY MIDDAY. THE LOW MOVES EAST BY MONDAY MORNING ENDING THE MAIN
PART OF PRECIP WEST TO EAST SUNDAY NIGHT. THERE WILL BE A BREAK
BEFORE THE NEXT STORM SYSTEM AFFECT THE REGION MONDAY NIGHT.
MODELS INDICATE THE PRECIP WILL BE MAINLY CONFINED TO NW WI. THE
QUESTION FOR THIS SYSTEM IS IF THE RAIN/SNOW SPREADS INTO DULUTH.
RIGHT NOW...WE WILL KEEP IT MAINLY SOUTH OF THE TWIN PORTS. THE
PROBLEMS WITH THE TWO SYSTEM WILL BE THE PRECIP AMOUNTS OF 0.33 TO
0.75 INCHES WHICH WILL ADD ADDITIONAL MOISTURE TO THE SNOW PACK.
THERE WILL BE A WARMUP NEXT WEEK WITH TEMPS INTO THE 40S WHICH
START THE SNOWMELT.
&&
.POINT TEMPS/POPS...
DLH 13 36 24 40 / 0 0 50 60
INL 7 36 23 42 / 0 0 50 60
BRD 12 37 28 45 / 0 10 70 60
HYR 8 37 24 45 / 70 0 60 70
ASX 16 36 23 43 / 80 0 40 50
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 9 AM CDT SATURDAY FOR LSZ121-146>148.
SMALL CRAFT ADVISORY UNTIL 4 AM CDT SATURDAY FOR LSZ140>142.
&&
$$
SHORT TERM...MELDE
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
352 PM EDT SAT APR 20 2013
.SYNOPSIS...
A BRISK AND COLD NORTHWEST FLOW OF AIR WILL BRING SCATTERED LIGHT
RAIN AND SNOW SHOWERS TO THE REGION INTO THIS EVENING. HIGH
PRESSURE WILL THEN BUILD IN ACROSS THE REGION LATE TONIGHT, WITH
CHILLY TEMPERATURES FOR THIS TIME OF YEAR. THE HIGH WILL LINGER
OVER THE NORTHEAST UNITED STATES INTO TUESDAY, WITH FAIR SKIES
AND SLOWLY MODERATING TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
330 PM UPDATE...
SHORT WAVE MOVING THROUGH NOW WITH SOME FLURRIES AND SPRINKLES
ACROSS MOST OF THE CWA. COLD AIR ADVECTION OCCURRING BEHIND A SFC
TROF. 850 MB TEMPS FALL TO -12C WHICH IS COLD ENOUGH FOR AT LEAST
LAKE EFFECT CLOUDS AND PROBABLY SNOW FLURRIES TOO. WITH THE WARM
GROUND IT WILL BE DIFFICULT FOR ANY SNOW TO STICK. AS USUAL MOST
LIKELY AT THE HIGHEST ELEVATIONS OF THE UPPER SUSQUEHANNA AND TUG
HILL. SNOW AMOUNTS DUSTING AT MOST. LOW LEVEL FLOW SHIFTS FROM
WEST TO NW THIS EVENING KEEPING CLOUDS IN NY AND THE NRN TIER OF
PA. WINDS WILL CONTINUE TO GUST INTO THE EVENING THEN FALL AS A
LARGE SURFACE HIGH MOVES IN LATE. THIS WILL SHUT DOWN THE SNOW
FLURRIES BUT NOT KILL ALL THE CLOUDS UNTIL DURING THE DAY SUNDAY
WITH SUNSHINE TO MIX IT OUT. COLD TONIGHT WITH TEMPS FALLING INTO
THE 20S. TONIGHT AND SUNDAY NIGHT WILL END UP WITHIN 5 DEGREES OF
THE RECORD DAILY LOWS.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
330 PM UPDATE...
SUNDAY MORNING SOME LINGERING LAKE MOISTURE IN THE FORM OF LOWER
CLOUDS BUT WITH WINDS SHIFTING TO NORTH AND NE NOTHING SHOULD BE
FALLING OUT OF IT. SUNDAY SURFACE HIGH PRESSURE OVER THE AREA WITH
THE WEAK UPPER LEVEL TROF MOVING EAST. WEAK WARM AIR ADVECTION
ALOFT AND TEMPERATURES MODERATING AT THE SURFACE. WITH THE HIGH
OVER THE AREA SUNDAY NIGHT LOW TEMPS WILL FALL BACK INTO THE 20S.
THE HIGH PRESSURE MOVES TO NOVA SCOTIA MONDAY AND SLOWS. A RIDGE
OF HIGH PRESSURE EXTENDS ALONG THE EAST COAST. AFTER A MOSTLY
SUNNY SUNDAY AFTERNOON AN ONSHORE FLOW WILL BRING MOISTURE IN FROM
THE SOUTHEAST SUNDAY NIGHT TO TUESDAY. SOME MODELS EVEN BRINGING
SOME LIGHT QPF. HAVE A SLIGHT CHANCE OF LIGHT RAIN SHOWERS AND
DRIZZLE MONDAY NIGHT AS A STORM MOVES NORTHEAST PARALLEL TO THE
COAST BUT WELL OFFSHORE. THE COLD FRONT DUE WED IS CLOSE ENOUGH TO
SHIFT THE WINDS TO SOUTH SCOURING OUT THE ATLANTIC MOISTURE TUE
AFTN.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A FAIRLY QUITE PD WX-WISE FOR THE MED RNG. OVERALL PTRN WILL
FEATURE THE DVLPMNT OF A FAIRLY BROAD TROF OVER THE CNTRL U.S..
A S/WV MOVING THRU THIS FEATURE AND IT`S ASSCD FNTL SYSTEM WILL
APRCH LATER TUE NGT AND CROSS THE FCST AREA ON WED WITH A BATCH OF
RAIN OR SHOWERS. AFTER THIS TIME...MDLS SUGGEST ONLY WEAK UPR LVL
IMPULSES WITH SFC RIDGING OCCURING...SO DRY WX WILL PREVAIL. NXT
FNTL SYSTEM MAY GET INTO THE RGN BY NXT WEEKEND. SO AFTER WED`S
RAIN...PARTLY TO MOSTLY SUNNY SKIES AND TEMPS GETTING BACK TO
SEASONAL NORMS. HPC GUIDANCE LOOKED GOOD AND WAS UTILZED WITH SOME
MINOR TWEEKS TO CLD GRIDS.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
VFR WILL PREVAIL THRU 18Z SUNDAY. SCT -SHRA ACRS CNTRL NY THIS
AFTN ASSCD WITH AN UPR LVL S/WV AND WEAK SFC TROF...BUT LTL IN THE
WAY OF RESTRICTIONS. XPCT THIS ACTIVITY TO WANE LATER THIS AFTN
AND EVNG. MAIN FCST CHALLENGE WAS DETERMINING THE POTNL FOR A PD
OF MVFR CIGS ACRS PORTIONS OF CNTRL NY LATER TNGT DUE TO COLD NW
FLOW ACRS THE LAKES. RUC PROFILES BCM VERY MOIST AT LOW LVLS
TNGT...IN CONTRAST TO OTHER MDLS INDICATING MUCH LESS SATURATION
OF LOWER LVLS. GIVEN THE STREAMERS ACRS THE GTLAKES TDA...BELIEVE
LAKE CLDS ARE LIKELY LATER TNGT SPCLY SYR/ITH AND PSBLY BGM...BUT
FOR NOW JUST INDICATED A BKN035 DECK. ANY CLDS TMRW MRNG WILL DSPT
RAPIDLY LEAVING SUNNY SKIES.
WINDS THIS AFTN WRLY 15-20 G25-30...DIMINISHING THIS EVNG...THEN
N TO NW WINDS 5-10 KTS SUN MRNG.
.OUTLOOK...
SUN NGT THROUGH MON...VFR UNDER HIGH PRESSURE.
MON NGT...PSBL MVFR FAR SRN NY AND NE PA DUE TO SE FLOW/MARINE
LAYER.
TUE/TUE NGT...VFR.
WED/WED NGT...MVFR IN SHRA.
THU...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN/TAC
NEAR TERM...TAC
SHORT TERM...TAC
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
153 PM EDT SAT APR 20 2013
.SYNOPSIS...
A BRISK AND COLD NORTHWEST FLOW OF AIR WILL BRING SCATTERED RAIN
SHOWERS, MIXED WITH A FEW SNOW SHOWERS AT TIMES TO THE REGION
TODAY. HIGH PRESSURE WILL THEN BUILD IN ACROSS THE REGION LATE
TONIGHT WITH VERY CHILLY TEMPERATURES FOR THIS TIME OF YEAR.
THIS HIGH PRESSURE SYSTEM WILL LINGER OVER THE NORTHEAST UNITED
STATES THROUGH EARLY NEXT WEEK, WITH FAIR SKIES AND SLOWLY
MODERATING TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
1030 AM UPDATE...
MINOR CHANGES. THE GRIDS ARE CLOSE TO ACTUAL. FOR THIS AFTERNOON
AND EVENING THE LOW LEVEL FLOW SHIFTS TO NW WITH VERY COLD AIR
ALOFT FOR LATE APRIL. UPPED CLOUDS, QPF, AND POPS MOSTLY IN
CENTRAL NY. LITTLE TO WORRY ABOUT TODAY AND TONIGHT. ONE SHORT
WAVE AND A NE TO SW LINE OF SHOWERS MOVING THROUGH NOW WITH MIXED
PRECIP. LITTLE IF ANY SNOW ACCUMULATION. ANOTHER SHORT WAVE AROUND
00Z WILL HELP THE LAKE ENHANCEMENT.
PREVIOUS DISCUSSION...
RADAR STILL SHOWS LINGERING SHOWERS IN NE PA AND THE CATSKILLS IN
ASSCTN WITH ANOTHER SHORT WAVE LIFTG NORTHEASTARD THRU THE ERN OH
VLLY TWD THE LOWER LAKES. THIS WAVE WAS APPARENT ON THE WV IMAGERY
AND ALSO CAPTURED WELL IN THE NAM12 DYNAMIC TROPAPAUSE FIELDS. THE
1.5 PV UNIT SFC DROPS DOWN TO ALMOST 600 MB IN NC OH ATTM. THIS
WAVE WILL CONT NORTHEAST EARLY THIS MORNING AND THIS LAST
LINGERING BATCH OF RAINS WILL ADVECT N AND E AND FINALLY EXIT NE
PA AND THE CATSKILLS BY ARND 10Z OR SO AS PER THE LATEST HRRR
MODEL WHICH SEEMS TO HAVE THE BEST HANDL ON THE PRECIP. HV POPS IN
THE SERN PART OF THE FORECAST AREA UNTIL 9-10Z.
ONCE THIS SHRT WAVE RAPIDLY LIFTS NORTHEAST LATER THIS MORNING
INTO SERN CANADA A STRG COLD AIR ADVECTION PATTERN SETS UP ACRS
ALL OF CENTRAL NY AND NORTHEAST PA. H85 TEMPS FALL TO BETWEEN -8 AND
-12C BY THIS EVE ACROSS MUCH OF CWA AS PER 00Z NAM AND GFS. THIS
IS REALLY CHILLY FOR THIS TIME OF YEAR. MODEL SOUNDINGS FOR ALL
AVBL MODELS SHOW PATCHY CLOUDS THIS MORNING RAPIDLY FILLING IN TO
A BKN-OVC SC/CU LAYER WITH INSOLATION GIVE THE CHILLY AIR ALOFT
AND A SHARP INVERSION ARND 800 TO 750 MB. SOUNDINGS SHOW SOME
SHALLOW CAPE UNDER THIS INVERSION SUGGESTING SHRA AND EVEN A MIX
OF RAIN AND SNOW DEVELOPING. NO SNOW ACCUMULATIONS EXPECTED BUT
IT WILL BE COLD ENUF AT TIMES FOR SNOW TO BE OBSERVED. SO WILL
HAVE SCT SHRA AND SN ESP THIS MORNING IN GRIDS. BY AFTERNOON BNDRY
LAYER DRIES OUT SOME AS MUCH LOWER SFC DEWPOINTS START WORKING IN
COUPLED WITH DRIER AIR ALOFT WHICH WILL MIX DOWN FROM ABV THE
INVERSION. I SEE CLDS EVENTUALLY SCATTERING OUT LATE IN THE DAY
INTO THE EVE WITH MINIMAL CHC/S FOR PRECIP BY THEN. HIGHEST POPS WILL
BE LATE MORNING TO MID AFTERNOON...THEN WANING.
PRESSURE GRADIENT WILL BECOME FAIRLY STRONG TODAY AND WITH
INSTABILITY PRESENT IN THE LL/S THERE IS SOME GUST POTENTIAL.
LOOKS LIKE THERE WILL BE A CHANCE OF WINDS TO COME CLOSE TO ADVY
AGAIN...ESP IN C NY. 12 HR PRESSURE RISES WERE ARND 10-12 MB/6 HR
WHICH IS MARGINAL FOR ADVY BASED ON LOCAL STUDY. SO THINK WE WILL SEE
A FEW GUSTS APPROACH 40 MPH AND NOT ISSUE AN ADVY AT THIS TIME.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
FOR TONIGHT...LARGE COLD SURFACE HIGH RAPIDLY BUILDS IN ACRS THE
EASTERN LAKES BY 12Z SUN. THIS WILL LEAD TO MAINLY CLEAR SKIES AND
WITH COLD TEMPERATURES PRESENT FROM THE STRG COLD AIR ADVECTION
TODAY...TONIGHT WILL BE A VERY COLD NIGHT FOR LATE APRIL. NAM MET
GUIDC HAS BGM DROPPING TO 20F WITH 6-7 KTS OF WIND....THIS IS ONE
DEGREE BELOW THE RECORD LOW FOR THE DATE! IN FACT THE MET GUIDC
HAS MIN/S TONIGHT ARND 20F ALL SITES WHICH IS CLOSE TO RECORD
LOWS. ALL SITES WILL MAINTAIN SOME WIND TOO WHICH IS INDICATIVE OF
HOW COLD THIS AIR MASS IS. THE GFS MOS IS A FEW DEGREES WARMER AND
AGAIN ALSO KEEPS THE WINDS UP WHICH WILL LIMIT THE NET RADITIONAL
COOLING POTENTIAL IN THE DEEPER VALLEYS. WILL GO WITH A BLEND OF
THE MET AND MOS FOR MINS TONIGHT. GROWING SEASON HAS NOT BEGUN YET
FOR ANY OF OUR FORECAST AREA SO NO HEADLINES FOR THE PROLONGED FREEZE
CONDITIONS.
THIS LARGE HIGH PRESSURE SYSTEM SLOWLY DRIFTS EASTWARD COVERING
NEW ENGLAND BY 00Z MON. THUS SUNDAY WILL START OFF VERY COLD BUT
THERE WILL BE AMPLE SUNSHINE. 850 MB TEMPS REMAIN BELOW -5C MOST
OF THE DAY INDICATIVE OF ANOTHER CHILLY DAY...BUT THE WIND WILL BE
MUCH LIGHTER. WITH SUCH DRY AIR IN THE LOW-LEVELS THERE WILL BE
LITTLE IF ANY CU FORMATION SUNDAY. SO I EXPECT SUNNY SKIES.
FOR SUNDAY NIGHT AND MONDAY THIS LARGE HIGH WILL CONT TO SLIDE
FARTHER EAST WELL OFF THE MARITIMES WITH A SIGNIFICANT COOL AIR
DAMMING SIGNATURE SETTING UP E OF THE APPLCNS. DWPTS WILL REMAIN
IN THE 20S AND LOW 30S FOR MOST OF THIS TIME PERIOD WITH LITTLE
CLD CVR EXPECTED. H85 TEMPS WILL REMAIN SLIGHTLY BELOW 0C
CONTINUING BELOW NORMAL TEMPERATURES. FOR MONDAY NIGHT...ONCE
AGAIN COOL AIR DAMMING SIGNATURE WILL REMAIN IN PLACE AS LOW
PRESSURE DEVELOPS SOUTH OF THE ABOVE MENTIONED LARGE HIGH PRESSURE
SYSTEM OFF THE MARITIMES AND TRACKS SLOWLY NORTHEAST WELL OFF THE
EAST COAST. HENCE PA AND NY WILL REMAIN IN BETWEEN THIS STORM AND
THE NEXT SYSTEM MOVING THRU THE GREAT LAKES WHICH REACHES NRN LWR
MI BY 12Z TUE. THUS I SEE A CONTINUATION OF FAIR AND DRY WEATHER
MON NGT AS WELL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
A FAIRLY QUITE PD WX-WISE FOR THE MED RNG. OVERALL PTRN WILL
FEATURE THE DVLPMNT OF A FAIRLY BROAD TROF OVER THE CNTRL U.S..
A S/WV MOVING THRU THIS FEATURE AND IT`S ASSCD FNTL SYSTEM WILL
APRCH LATER TUE NGT AND CROSS THE FCST AREA ON WED WITH A BATCH OF
RAIN OR SHOWERS. AFTER THIS TIME...MDLS SUGGEST ONLY WEAK UPR LVL
IMPULSES WITH SFC RIDGING OCCURING...SO DRY WX WILL PREVAIL. NXT
FNTL SYSTEM MAY GET INTO THE RGN BY NXT WEEKEND. SO AFTER WED`S
RAIN...PARTLY TO MOSTLY SUNNY SKIES AND TEMPS GETTING BACK TO
SEASONAL NORMS. HPC GUIDANCE LOOKED GOOD AND WAS UTILZED WITH SOME
MINOR TWEEKS TO CLD GRIDS.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
VFR WILL PREVAIL THRU 18Z SUNDAY. SCT -SHRA ACRS CNTRL NY THIS
AFTN ASSCD WITH AN UPR LVL S/WV AND WEAK SFC TROF...BUT LTL IN THE
WAY OF RESTRICTIONS. XPCT THIS ACTIVITY TO WANE LATER THIS AFTN
AND EVNG. MAIN FCST CHALLENGE WAS DETERMINING THE POTNL FOR A PD
OF MVFR CIGS ACRS PORTIONS OF CNTRL NY LATER TNGT DUE TO COLD NW
FLOW ACRS THE LAKES. RUC PROFILES BCM VERY MOIST AT LOW LVLS
TNGT...IN CONTRAST TO OTHER MDLS INDICATING MUCH LESS SATURATION
OF LOWER LVLS. GIVEN THE STREAMERS ACRS THE GTLAKES TDA...BELIEVE
LAKE CLDS ARE LIKELY LATER TNGT SPCLY SYR/ITH AND PSBLY BGM...BUT
FOR NOW JUST INDICATED A BKN035 DECK. ANY CLDS TMRW MRNG WILL DSPT
RAPIDLY LEAVING SUNNY SKIES.
WINDS THIS AFTN WRLY 15-20 G25-30...DIMINISHING THIS EVNG...THEN
N TO NW WINDS 5-10 KTS SUN MRNG.
.OUTLOOK...
SUN NGT THROUGH MON...VFR UNDER HIGH PRESSURE.
MON NGT...PSBL MVFR FAR SRN NY AND NE PA DUE TO SE FLOW/MARINE
LAYER.
TUE/TUE NGT...VFR.
WED/WED NGT...MVFR IN SHRA.
THU...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN/TAC
SHORT TERM...MDP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
640 AM EDT SAT APR 20 2013
.SYNOPSIS...
A STRONG COLD FRONT SWEEPS OFFSHORE THIS MORNING. IN THE WAKE OF THE
COLD FRONT...COOLER HIGH PRESSURE BUILDS INTO THE REGION FROM THE
NORTH OVER THE WEEKEND. A WEAK LOW PRESSURE SYSTEM DEVELOPS OFF THE
CAROLINA COAST LATE SUNDAY NIGHT INTO MONDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 640 AM SATURDAY...
DRY AIR IN THE MID-LEVELS CONTINUED TO SLOWLY MOVE OVER THE
WESTERN PART OF THE STATE ON WATER VAPOR IMAGERY...THOUGH APPARENT
MID-LEVEL SHORTWAVES IN THE SOUTHWEST FLOW ALOFT WERE RESULTING IN A
RIPPLED APPEARANCE TO THE MOISTURE ON WATER VAPOR LOOPS. THE LATEST
WSR-88D COMPOSITE WAS FAIRLY SIMILAR TO AN EVENING RUN OF THE
HIGH-RES RAPID REFRESH WRF...AND NUMEROUS SHOWERS HAD JUST MOVED
EAST OF THE INTERSTATE 95 CORRIDOR. IN THE SOUTHWEST FLOW ALOFT...
HIGH-LEVEL RELATIVE HUMIDITY FORECASTS FROM THE NAM...RUC...AND
THE GFS SUGGEST A SLOW CLEARING TREND TO THE HIGH CLOUDS DURING THE
DAY...WITH THE GFS AND RUC SLOWEST AND SUGGESTIVE OF THE WESTERN
EDGE OF THE CIRRUS SHIELD NOT GETTING MUCH PAST INTERSTATE 95 UNTIL
AS LATE AS 20Z. THE FORECAST FOR TODAY WILL FEATURE A GRADUAL
WEST-TO-EAST CLEARING TREND WITH HIGHS IN THE MID 60S...NEAR THE
WARMER GUIDANCE OF THE MAV TOWARD THE TRIAD AND NEAR COOLER VALUES
OR EVEN A DEGREE OR TWO BELOW GUIDANCE FARTHER EAST. WINDS WILL
BECOME NORTHWEST IN THE FRONTAL TROUGH EARLY THIS MORNING ACROSS
CENTRAL NORTH CAROLINA...WITH A SLACKENING GRADIENT FORECAST BY BOTH
THE NAM AND THE GFS BY AFTERNOON AS WINDS VEER TO NORTH TO NORTHEAST
AND BECOME LIGHT BY EVENING.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
AS OF 305 AM SATURDAY...
TONIGHT AND SUNDAY...
HIGH PRESSURE BUILDS INTO CENTRAL NORTH CAROLINA OVERNIGHT...AND THE
GRADIENT TIGHTENS WITH THE RIDGING. IN ADDITION...IN THE
WEST-SOUTHWEST FLOW ALOFT...BOTH THE NAM AND THE GFS SUGGEST AN
INCREASE IN UPPER-LEVEL MOISTURE MOVING INTO THE REGION OVERNIGHT.
THE MIXING THAT SHOULD OCCUR OVERNIGHT AS THE HIGH BUILDS IN...WITH
AN INCREASE IN THE WIND...ALONG WITH SOME HIGH CLOUDS...SHOULD KEEP
TEMPERATURES FROM FALLING TOO FAR. GUIDANCE MINS APPEAR REASONABLE...
WITH MOST LOCATIONS SEEING LOWS IN THE UPPER 30S TO AROUND 40
DEGREES...POSSIBLY A CATEGORY COOLER IN THE TYPICALLY COOLER AREAS
NORTHEAST OF THE TRIANGLE...WHERE ANY HIGH CLOUDS WILL ARRIVE LATER.
SUNDAY...HIGH PRESSURE REMAINS OVER THE AREA AND SUBSIDENCE
CONTINUES. UNDER AREAS OF HIGH CLOUDS BASED ON THE UPPER-LEVEL
RELATIVE HUMIDITY FIELDS OF THE NAM AND GFS...AND WITH A MODEERATELY
GUSTY NORTHEAST WIND WITH 1000-850MB THICKNESSES ABOUT 10METERS LESS
ON AVERAGE COMPARED TO TODAY...HIGHS SHOULD BE SLIGHTLY COOLER...
MAINLY 60 TO 65.
SUNDAY NIGHT...DIFFERENCES IN THE NAM AND GFS START TO SHOW
THEMSELVES MORE PROMINENTLY. THE GFS IS FLATTER WITH THE UPPER FLOW
AND THE 500MB JET IS ORIENTED MORE WEST-TO-EAST AND FARTHER SOUTH
OVER SOUTHERN SOUTH CAROLINA BY 12Z MONDAY. THIS KEEPS THE BEST LIFT
AND MOISTURE ALONG AND NEAR THE COAST...POSSIBLY PENETRATING INLAND
TOWARD KCTZ. ON THE OTHER HAND...THE NAM IS JUST SLIGHTLY SHARPER
WITH THE UPPER TROUGH AND ITS MID-LEVEL JET BECOMES ORIENTED A
LITTLE MORE SOUTHWEST-TO-NORTHEAST. THIS RESULTS IN CLOUDS
PENETRATING FARTHER INLAND ALONG WITH CHANCES FOR PRECIPITATION. THE
NAM PRECIPITABLE WATER OVER THE SOUTHWEST PIEDMONT...WHERE IT
FORECASTS MEAGER QPF LATE SUNDAY NIGHT...IS ONLY ABOUT AS HIGH AS A
HALF-INCH UNDER MID-LEVEL NVA...AND BUFR SOUNDINGS FROM THE NAM
CLEARLY SHOW AMPLE MID-LEVEL DRYING PERSISTING UNTIL 12Z MONDAY OVER
MUCH OF CENTRAL NORTH CAROLINA. THINK THE BETTER CHANCES OF ANY
MEASURABLE RAIN WILL BE AS PREVIOUSLY FORECAST AND MAINLY ORIENTED
LATE SUNDAY NIGHT ALONG AND EAST OF A LINE FROM ABOUT KMEB TO KGSB...
A LITTLE MORE SIMILAR TO THE GFS. HOWEVER...THERE IS CONCERN ABOUT
THE DEGREE IN WHICH SOME LOW-LEVEL MOISTURE WILL BE ABLE TO
PENETRATE INLAND IN A PERSISTENT NORTHEAST FLOW THAT BECOMES MORE
EASTERLY OVERNIGHT. LEANED A LITTLE MORE TOWARD THE NAM IN THAT
RESPECT. REGARDLESS...CONFIDENCE DOES START TO DECREASE WITH THE
FORECAST OVERNIGHT SUNDAY...BUT FOR THIS FORECAST WILL FEATURE AN
INCREASE IN CLOUDS WITH ONLY A CHANCE OF RAIN MAINLY SOUTHEAST WITH
OVERNIGHT LOWS A BLEND OF THE MAV AND MET MOS GUIDANCE...MAINLY 40
TO 45. -DJF
MONDAY AND MONDAY NIGHT...
DIFFICULT FORECAST FOR THIS PERIOD...AS A WEAK SHORTWAVE IS
EXPECTED TO MOVE ACROSS THE AREA IN THE BROAD CYCLONIC FLOW ACROSS
THE CONUS AND INDUCE CYCLOGENESIS JUST OFF THE SOUTHEAST U.S. COAST
ALONG THE LINGERING OLD FRONTAL ZONE. THIS SURFACE LOW IS EXPECTED
TO TRACK NORTH-NORTHEASTWARD JUST OFF THE COAST OF THE CAROLINAS
MONDAY AND MONDAY NIGHT. HOW CLOSE TO THE COAST THIS SURFACE LOW
TRACKS AS IT PASSES BY THE COAST OF THE CAROLINAS WILL HAVE A
SIGNIFICANT IMPACT ON HOW MUCH RAIN AND CLOUD COVER WE WILL SEE...
ALONG WITH A BIG IMPACT ON HIGH AND LOW TEMPS. THUS...FORECAST
CONFIDENCE WITH REGARD TO THESE ITEMS IS LOW AT THIS TIME.
THE 00Z NAM AND 12Z ECMWF SHOW THE SURFACE LOW TRACKING CLOSER TO
OUR COAST THAN THE 00Z GFS...WITH THE 12Z ECENS MEAN GIVEN SUPPORT
TO A NAM/ECMWF BLEND. THUS...WILL GO WITH A BLEND OF THE
NAM/ECMWF...WHICH FAVORS A CHANCE FOR LIGHT RAIN ACROSS AT LEAST
EASTERN PORTIONS OF CENTRAL NC...AND MOSTLY CLOUDY TO OVERCAST
SKIES. WILL CONTINUE TO TREND HIGH TEMPS COOLER THAN GUIDANCE...
GIVEN THE STRONG 1043-1045 MB SURFACE HIGH EXTENDING SOUTHWARD INTO
OUR AREA DURING THIS TIME FROM NEW ENGLAND/SOUTHEAST CANADA. THIS
WOULD FAVOR THE DEVELOPMENT OF A CAD AIRMASS ACROSS CENTRAL NC...
SO WILL GO WITH HIGH TEMPS IN THE UPPER 50S ACROSS THE AREA...WITH
THE POTENTIAL FOR HIGHS POSSIBLY A CATEGORY COOLER IF MORE PRECIP IS
REALIZED THAN CURRENTLY EXPECTED (TRACE WEST TO NEAR A TENTH OF AN
INCH EAST). WITH RESPECT TO POPS WILL KEEP CHANCE EAST TO SLIGHT
CHANCE WEST FOR NOW MONDAY INTO MONDAY EVENING...WITH ONLY LIGHT
RAINFALL AMOUNTS EXPECTED THOUGH. THE SURFACE LOW SHOULD BE LIFTING
OFF TO THE NORTHEAST EARLY TUESDAY MORNING...ALONG WITH THE PASSAGE
OF THE MID LEVEL SHORTWAVE. THIS SHOULD USHER DRIER AIR ALOFT INTO
THE AREA...ALONG WITH A MORE NORTHERLY COMPONENT TO THE LOW LEVEL
FLOW (VS THE MOIST EASTERLY FLOW). WILL SHOW CHANCES FOR PRECIP
ENDING EARLY TUESDAY MORNING...HOWEVER...STILL THINK WE WILL HOLD
ONTO OUR LOW CLOUD UNTIL AT LEAST SUNRISE. THUS...EXPECT LOWS TO BE
ON THE WARMER SIDE OF GUIDANCE...GIVEN THE EXPECTED CLOUD COVER (AS
THE GFS HAS MUCH LESS CLOUD COVER)...AND WILL GO WITH LOW TEMPS
RANGING FROM THE MID 40S WEST TO AROUND 50 EAST. -BSD
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 305 AM SATURDAY...
BRIEF SHORTWAVE RIDGING IS EXPECTED TO BUILD ACROSS THE REGION ON
TUESDAY... BEFORE THE NEXT SIGNIFICANT TROUGH AND ASSOCIATED COLD
FRONT APPROACH THE AREA ON WEDNESDAY AND CROSS THE REGION LATE
WEDNESDAY INTO WEDNESDAY NIGHT.... WITH SHOWERS AND/OR STORMS
POSSIBLY LINGERING INTO THURSDAY MORNING. HOWEVER... GIVEN THE
SURFACE RIDGE IS EXPECTED TO HOLD ACROSS THE AREA UNTIL TUESDAY
NIGHT... THERE WILL ONLY BE A BRIEF PERIOD OF A MOISTENING SOUTHERLY
RETURN FLOW. THUS... GIVEN THIS AND THE POSSIBILITY OF THE TROUGH
ALOFT BEGIN A BIT WEAKER... THINK THIS SYSTEM (AS IT STANDS NOW)
SHOULD BE MUCH WEAKER THAN THE ONE WHICH JUST MOVED THROUGH THE AREA
YESTERDAY/EARLY THIS MORNING. THINK WE SHOULD SEE A BAND OF SHOWERS
AND PERHAPS A FEW THUNDERSTORMS LATE WEDNESDAY INTO WEDNESDAY
NIGHT/THURSDAY MORNING AS THE LOW LEVEL FRONTAL ZONE MOVES ACROSS
THE AREA. HIGH PRESSURE WILL BUILD INTO CENTRAL NC IN THE WAKE OF
THE SYSTEM ON THURSDAY AFTERNOON... AND REMAIN ACROSS THE AREA
THROUGH THE END OF THE FORECAST PERIOD (FRIDAY).
HIGH TEMPS DURING THE EXTEND WILL GENERALLY RUN BELOW NORMAL... WITH
THE WARMEST DAY EXPECTED TO BE WEDNESDAY. WILL FORECAST HIGHS IN THE
70S AREAWIDE WEDNESDAY... WITH GENERALLY MID TO UPPER 60S (NEAR 70
SOUTH) FOR TUESDAY AND THURSDAY/FRIDAY. LOW TEMPS ARE EXPECTED TO BE
IN THE LOWER 50S ON WEDNESDAY MORNING IN ADVANCE OF THE FRONT...
WITH GENERALLY 40S THURSDAY AND FRIDAY MORNINGS.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 640 AM SATURDAY...
VFR CONDITIONS ARE EXPECTED THROUGH THE 12Z VALID TAF PERIOD...
OUTSIDE OF A FEW AREAS OF MVFR CONDITIONS IN RAIN SHOWERS VERY EARLY
THIS MORNING SOUTH AND EAST OF KRWI AS A COLD FRONT MOVES OFFSHORE.
IN THE SOUTHWEST FLOW ALOFT...THE BACK EDGE OF HIGH CLOUDS SHOULD BE
SLOW TO MOVE EAST. EVENTUALLY...BY 20Z...THAT BACK EDGE SHOULD BE
THROUGH THE CENTRAL NORTH CAROLINA COASTAL PLAIN.
BEYOND THE 12Z VALID TAF PERIOD...VFR CONDITIONS OCCUR SUNDAY INTO
SUNDAY NIGHT. THERE IS A CHANCE OF MVFR CONDITIONS IN LOWER CLOUDS
SPREADING FROM THE COAST TOWARD CENTRAL NORTH CAROLINA BY LATE
SUNDAY NIGHT. THIS WILL DEPEND ON HOW CLOSE TO THE COAST WEAK LOW
PRESSURE DEVELOPS WITH THE GUIDANCE DIFFERING ON THE AMOUNT AND TYPE
OF CLOUD COVER THAT OCCURS OVER CENTRAL NORTH CAROLINA THEN. HIGHER
CHANCES OF THESE CLOUDS WILL BE TOWARD KFAY AND KRWI. THERE IS THEN
A CHANCE OF IFR CONDITIONS IN LOW CLOUDS MONDAY NIGHT INTO EARLY
TUESDAY...AND AGAIN EARLY WEDNESDAY...WITH AREAS OF MVFR CLOUDS
POSSIBLE BEFORE MIXING LIFTS ANY MVFR CLOUD HEIGHTS TO VFR DURING
WEDNESDAY AFTERNOON.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF
SHORT TERM...DJF/BSD
LONG TERM...BSD
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1259 AM CDT SAT APR 20 2013
.UPDATE...
ISSUED AT 1259 AM CDT SAT APR 20 2013
LATEST RADAR IMAGERY AT 0545Z SHOWS SOME LIGHT RETURNS OVER THE
FAR WEST AND SOUTHWEST. HOWEVER...AT THIS TIME THERE HAVE BEEN NO
SURFACE OBSERVATIONS REPORTING ANY PRECIP REACHING THE SURFACE. SO
BASED OFF THE LATEST RUN OF THE RAP (04Z)...HAVE SCALED BACK POPS
OVER THE NEXT FEW HOURS FOR THE WEST. OTHERWISE...FORECAST IS IN
GOOD SHAPE AND MADE ADJUSTMENTS BASED OFF LATEST OBSERVATIONS AND
TRENDS AT 05Z.
UPDATE ISSUED AT 956 PM CDT FRI APR 19 2013
BASED ON LATEST SHORT RANGE MODEL TRENDS...HAVE SLOWED TIMING OF
POPS FROM WEST TO EAST...OVERNIGHT THROUGH SATURDAY. EXPECTED QPF
AMOUNTS STILL SUPPORT AROUND AN INCH OF NEW SNOW THROUGH THE AFTERNOON.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 325 PM CDT FRI APR 19 2013
LATEST SATELLITE IMAGERY SHOWS CLEAR SKIES OVER ALL BUT THE FAR
SOUTHWEST PORTION OF THE CWA THIS AFTERNOON. SURFACE LOW PRESSURE
IS DEEPENING OVER THE CANADIAN AND NORTHERN U.S. ROCKIES WHILE
SURFACE HIGH PRESSURE REMAINS OVER THE CENTRAL DAKOTAS INTO
MANITOBA AND SASKATCHEWAN. AREA RADARS INDICATED LIGHT
REFLECTIVITIES OVER CENTRAL MONTANA...WEST OF GLASGOW AND MILES
CITY.
THE MAIN FORECAST PROBLEM FOR TONIGHT AND SATURDAY WILL BE
TRACKING THIS AREA OF WARM ADVECTION EAST ACROSS THE LOCAL AREA.
MODELS ARE CONSISTENT IN BRINGING A BAND OF WARM ADVECTION WEST TO
EAST ACROSS THE AREA...BEGINNING THIS EVENING IN THE FAR WEST.
MODELS ARE A LITTLE SLOWER THAN THE PREVIOUS FORECAST AND
THEREFORE THE MAIN CHANGE WAS TO SLOW THE TIMING OF THIS SYSTEM.
WITH THE LEADING EDGE MOVING INTO THE FAR WEST THIS EVENING...WE
COULD SEE A PRECIPITATION BEGIN AS RAIN OR A RAIN/SNOW MIX IN THE
FAR SOUTHWEST. FORECAST SOUNDINGS INDICATE THIS WOULD BE SHORT
LIVED BEFORE A CHANGE TO ALL SNOW. THE MAJORITY OF PRECIPITATION
SHOULD FALL AS SNOW AS IT WORKS ITS WAY INTO CENTRAL NORTH DAKOTA
TONIGHT...THEN ACROSS THE CENTRAL ON SATURDAY.
ON SATURDAY...AFTER THE MAIN WARM ADVECTION FORCING...UPPER LEVEL
FLOW REMAINS CONDUCIVE FOR SHORTWAVES TO TRAVERSE THE FORECAST
AREA. WITH AFTERNOON HEATING WE ALSO BECOME SLIGHTLY UNSTABLE IN
THE FAR SOUTHWEST. WOULD NOT BE SURPRISED TO SEE SOME THUNDERSTORM
ACTIVITY APPROACH THE SOUTHWEST SATURDAY AFTERNOON...BUT WITH
SOME SNOW REMAINING ON THE GROUND...THINK THIS MAY BE JUST ENOUGH
TO SUPPRESS SURFACE HEATING ENOUGH FOR CONVECTION. WILL KEEP IT
OUT FOR NOW. WE WILL SEE WARMER TEMPERATURES IN THE WEST WITH
HIGHS APPROACHING 50 DEGREES...WHICH STILL REMAINS BELOW NORMAL.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 325 PM CDT FRI APR 19 2013
THE HIGHLIGHT OF THE EXTENDED FORECAST IS THE CONTINUATION OF BELOW
NORMAL TEMPERATURES ACROSS WESTERN AND CENTRAL NORTH DAKOTA UNDER A
BROAD UPPER LEVEL LONGWAVE CONUS TROUGH. THE 12 UTC DETERMINISTIC
SUITE IS IN GOOD AGREEMENT ON THE OVERALL PATTERN THROUGH THE
EXTENDED AND UTILIZED A BLEND FOR MOST FORECAST FIELDS.
THIS WEEKEND DOES LOOK TO BE A BIT UNSETTLED AS ENERGY CURRENTLY
ACROSS FAR NORTHWEST BRITISH COLUMBIA PROPAGATES INTO THE NORTHERN
PLAINS. SCATTERED PRECIPITATION IS EXPECTED DURING THE DAYTIME
SATURDAY WITH MORE WIDESPREAD AND RELATIVELY HEAVIER PRECIPITATION
SATURDAY NIGHT INTO SUNDAY...ESPECIALLY ACROSS NORTHERN NORTH DAKOTA
CLOSER TO THE SHORTWAVE. RAIN IS FAVORED ACROSS SOUTHERN NORTH
DAKOTA DURING THE DAYTIME...WITH A MIX OR ALL SNOW AT NIGHT. MOSTLY
SNOW IS EXPECTED ACROSS NORTHERN NORTH DAKOTA WITH COOLER AIR IN
PLACE. ANY SNOWFALL AMOUNTS WILL BE MINIMAL...WITH PERHAPS AN INCH
OF ACCUMULATION ALONG AND NORTH OF US HIGHWAY 2. WHILE TEMPERATURES
ARE EXPECTED TO REMAIN BELOW AVERAGE THROUGH NEXT WEEK UNDER
NORTHWEST FLOW ALOFT...THE UPPER LEVEL TROUGH AXIS DOES SLOWLY SHIFT
EAST NEXT WEEK...ALLOWING FOR A SLOW WARM UP RELATIVE TO THE CHILLY
WEEKEND. THE 12 UTC DETERMINISTIC SOLUTIONS AND ENSEMBLES CONTINUE
TO PUSH BACK THE PATTERN CHANGE TO NEAR NORMAL TEMPERATURES WITH
UPPER LEVEL RIDGING TO PERHAPS THE APRIL 30 OR MAY 1 TIMEFRAME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1259 AM CDT SAT APR 20 2013
SOUTHEAST FLOW WILL INCREASE THROUGH THIS MORNING FROM WEST TO
EAST ACROSS ALL TERMINALS. LIGHT SNOW WILL DEVELOP FOR KDIK/KISN
AFTER 10Z...KBIS/KMOT AFTER 15Z...AND KJMS AFTER 21Z. THERE WILL
BE A PERIOD OF A RAIN/SNOW MIX AT KDIK/KISN/KBIS DURING THE LATE
MORNING...AND CONTINUE THROUGH 03/04Z FOR KBIS/ISN...AND THROUGH
THE REMAINDER OF THE 06Z TAF CYCLE FOR KDIK.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...LTH
SHORT TERM...TWH
LONG TERM...AYD
AVIATION...LTH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1132 PM CDT FRI APR 19 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 313 PM CDT FRI APR 19 2013
MAIN FORECAST CONCERNS ARE ON LINGERING SNOW/RAIN SHOWERS THIS
EVENING. FOCUS THEN TURNS TO PRECIPITATION CHANCES AND TEMPERATURES
SATURDAY NIGHT INTO SUNDAY.
LATEST WATER VAPOR IMAGERY AND 500 MB RAP ANALYSIS PLACED LOW
PRESSURE OVER CENTRAL LAKE SUPERIOR...MOVING NORTHEAST. CYCLONIC
FLOW WAS IMPACTING THE FORECAST AREA ON THE BACK SIDE OF THE
LOW. THIS CYCLONIC FLOW COUPLED WITH STEEP LAPSE RATES HAS
PRODUCED WIDESPREAD SNOW SHOWERS THROUGH MUCH OF THE DAY.
SCATTERED SNOW SHOWERS WILL LINGER INTO THE EARLY EVENING THEN
DISSIPATE AS THE LOW LIFTS NORTHEAST AND SURFACE TEMPERATURES COOL.
HIGH PRESSURE WILL GRADUALLY BUILD INTO THE FORECAST AREA TONIGHT
INTO EARLY SATURDAY MORNING. IT WILL TAKE SOME TIME TO SCOUR OUT THE
LOW LEVEL MOISTURE AND THE NAM AND GFS HANG ONTO THIS MOISTURE WELL
INTO THE EVENING HOURS. LOOKING AT OBSERVATIONS AND VISIBLE SATELLITE
UPSTREAM ACROSS WESTERN INTO CENTRAL MINNESOTA THERE IS A WELL
DEFINED CLEARING LINE AND A LACK OF CUMULUS DEVELOPMENT TODAY
THANKS TO THE FRESH SNOW COVER IN PLACE KEEPING SURFACE
TEMPERATURES COOL. PLAN ON A GRADUAL CLEARING TREND FROM WEST TO
EAST TONIGHT...WITH THE CLEARING APPROACHING THE MISSISSIPPI RIVER
LATE IN THE EVENING THEN PROGRESSING EAST THROUGH THE OVERNIGHT
HOURS. SKIES WILL BE MOSTLY SUNNY SATURDAY MORNING AS COOL HIGH
PRESSURE SLIDES OVERHEAD. THE SUNNY SKIES WILL BE SHORT LIVED ON
SATURDAY AS A SHORTWAVE TROUGH APPROACHES FROM THE NORTHERN PLAINS
WITH INCREASING HIGH CLOUDS EXPECTED DURING THE LATE AFTERNOON
HOURS. THE HIGH WILL QUICKLY PUSH EAST OF THE REGION SATURDAY
EVENING AS THE SHORTWAVE APPROACHES THE UPPER MISSISSIPPI RIVER
VALLEY AND SURFACE LOW PRESSURE DEEPENS OVER THE CENTRAL/NORTHERN
PLAINS. PLAN ON HIGH TEMPERATURES ON SATURDAY RANGING FROM THE
UPPER 30S OVER NORTH CENTRAL WISCONSIN TO THE MID 40S ACROSS
NORTHEAST IOWA.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 313 PM CDT FRI APR 19 2013
SOUTHERLY FLOW WILL INCREASE ACROSS THE REGION AHEAD OF THE LOW.
STRONG 850MB WARM AIR ADVECTION INCREASES ACROSS THE FORECAST AREA
IN THE 6Z-12Z TIMEFRAME. PLAN ON RAIN/SNOW SHOWERS DEVELOPING ACROSS
THE AREA AS THIS SHORTWAVE MOVES IN AND WARM AIR ADVECTION
INCREASES. FORECAST SOUNDINGS SHOW A DRY LAYER NEAR THE
SURFACE...MAINLY BELOW 3KFT. AS PRECIPITATION FALLS INTO THIS
LAYER...EVAPORATION WILL COOL THE LOWER LEVELS LEADING TO A SWITCH
FROM RAIN INITIALLY OVER TO A PERIOD OF SNOW. SURFACE TEMPERATURES
WARM IN THE 12 TO 15Z...SOUTH OF INTERSTATE 94...SO EXPECTING TO
SEE A SWITCH OVER TO ALL RAIN ACROSS THESE AREAS. NORTH OF I-94 IT
WILL TAKE A LITTLE LONGER FOR SURFACE TEMPERATURES TO WARM WHERE
THE SWITCH OVER LOOKS TO OCCUR AFTER 17Z. A SLIGHTLY WARMER AND
UNSTABLE AIRMASS MOVES INTO THE AREA SUNDAY AFTERNOON WITH 0-3 KM
MUCAPE VALUES INCREASING TO AROUND 500 J/KG. COULD SEE SOME
ISOLATED TO SCATTERED THUNDERSTORMS SUNDAY AFTERNOON INTO SUNDAY
EVENING. THERE IS THE POTENTIAL FOR SOME SMALL HAIL WITH ANY
THUNDERSTORMS THAT DEVELOP WEST OF THE MISSISSIPPI RIVER. CAPE AND
SHEAR PROFILES ARE RATHER WEAK SO NOT ANTICIPATING SEVERE
THUNDERSTORMS AT THIS TIME. THERE ARE SOME INDICATIONS THAT THE
FRONT COULD SLIDE THROUGH LATER...PLACING THUNDERSTORM POTENTIAL
OVER THE FORECAST AREA AGAIN ON MONDAY. IF THIS SCENARIO PLAYS
OUT...THERE IS THE POSSIBILITY OF THUNDERSTORMS AGAIN ON MONDAY
MAINLY ALONG AND SOUTH OF INTERSTATE 90. A SECONDARY TROUGH DIVES
SOUTHEAST OUT OF WESTERN CANADA AND INTO THE PLAINS SUNDAY NIGHT
INTO MONDAY. A COLD FRONT...STRETCHING FROM NORTHEAST MINNESOTA
SOUTHWEST INTO SOUTHEASTERN SOUTH DAKOTA...WILL SLIDE SOUTHEAST
SUNDAY NIGHT THROUGH MONDAY AS THE WAVE DIGS SOUTH. SOME
DIFFERENCES NOTED IN THE FORECAST MODELS MONDAY INTO TUESDAY AS
ANOTHER WAVE DIVES SOUTH OUT OF THE PACIFIC NORTHWEST AND INTO THE
CENTRAL PLAINS. THE GFS PUSHES THE COLD FRONT SOUTH ON MONDAY AS
THE SHORTWAVE EJECTS OUT OF THE CENTRAL PLAINS AND INTERACTS WITH
THE FRONT OVER THE FORECAST AREA. THIS SCENARIO WOULD PRODUCE
SIGNIFICANT RAINFALL AND EVEN SOME SNOW ACROSS PORTIONS OF
SOUTHEAST MINNESOTA THROUGH NORTH CENTRAL WISCONSIN MONDAY NIGHT
INTO TUESDAY. THE GEM SOLUTION IS ALSO ON BOARD WITH THE GFS BUT
IS SLOWER WITH THE WAVE BRINGING IT INTO THE FORECAST AREA TUESDAY
INTO TUESDAY NIGHT. THE 19.12 ECMWF IS MORE IN LINE WITH THE GEM
SOLUTION AND ALSO PRODUCES A SWATH OF ACCUMULATING SNOW ACROSS
SOUTHEAST MINNESOTA THROUGH NORTH CENTRAL WISCONSIN WITH
TEMPERATURES WARM ENOUGH FOR RAIN TO MIX IN OVER PORTIONS OF
NORTHEAST IOWA INTO FAR SOUTHWEST WISCONSIN. GIVEN THE
UNCERTAINTIES IN THE TRACK AND TINNING OF THIS SYSTEM ITS DIFFICULT
TO PIN DOWN EXACT PRECIPITATION TYPE AND AMOUNTS. WILL HAVE TO
KEEP A VERY CLOSE WATCH ON THIS SYSTEM IMPACTING THE REGION IN THE
MONDAY THROUGH WEDNESDAY TIMEFRAME. WELL BELOW NORMAL TEMPERATURES
ARE EXPECTED THE LAST HALF OF THE WORK WEEK AS NORTHWEST FLOW
ALOFT SETS UP OVER THE REGION. AFTER A BRIEF RETURN TO SLIGHTLY
MORE SEASONABLE TEMPERATURES SUN-MON WITH HIGHS IN THE 50S...HIGHS
WILL FALL BACK INTO THE 40S TO AROUND 50 WEDNESDAY INTO THURSDAY.
THE ACTIVE PATTERN CONTINUES THURSDAY INTO FRIDAY AS ANOTHER
TROUGH TAKES AIM ON THE REGION VIA NORTHWEST FLOW ALOFT. THIS
FEATURE WILL BRING RAIN AND SNOW CHANCES TO THE AREA ON THURSDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1132 PM CDT FRI APR 19 2013
SKIES HAVE GRADUALLY BEEN CLEARING ACROSS THE REGION WITH SNOW
SHOWER ACTIVITY GREATLY DECREASING AS WELL. EXPECT THAT SKY
CONDITIONS WILL CONTINUE TO CLEAR THROUGH THE OVERNIGHT HOURS WITH
SOME FAIR WEATHER VFR CU POSSIBLY FORMING LATE TOMORROW
MORNING/EARLY AFTERNOON. WINDS WILL GO LIGHT AS A RIDGE OF HIGH
PRESSURE MOVES INTO THE REGION. MID LEVEL CLOUD COVER WILL THEN BE
ON THE INCREASE TOMORROW EVENING AS THE NEXT SYSTEM MOVES INTO THE
REGION FROM THE WEST.
&&
.HYDROLOGY...
ISSUED AT 313 PM CDT FRI APR 19 2013
FLOODING IS CURRENTLY OCCURRING ALONG PORTIONS OF THE BLACK RIVER.
PORTIONS OF THE TREMPEALEAU RIVER ARE RUNNING NEAR OR SLIGHTLY
ABOVE FLOOD STAGE. RECENT RAINFALL WILL KEEP THESE RIVERS NEAR OR
ABOVE FLOOD STAGE THROUGH THE WEEKEND. WET CONDITIONS WILL PERSIST
INTO THE EARLY PART OF THE WORK WEEK.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...HALBACH
HYDROLOGY...WETENKAMP
AREA FORECAST DISCUSSION
NWS MIAMI FL
328 AM EDT MON APR 22 2013
.SHORT TERM (TODAY THROUGH WEDNESDAY)...
THE GLOBAL MODELS ARE IN GENERAL AGREEMENT WITH THE OVERALL SYNOPTIC
SHORT TERM PATTERN IN DEPICTING A NEAR ZONAL FLOW ACROSS MUCH OF
SOUTHEASTERN STATES ALONG WITH A STATIONARY SURFACE FRONTAL TROUGH
ACROSS SOUTH CENTRAL FLORIDA. A FAST MOVING SOUTHERN STREAM MID
LEVEL TROUGH EMBEDDED WITHIN THIS FLOW IS CURRENTLY MOVING INTO THE
EASTERN GULF OF MEXICO AND WILL MOVE ACROSS THE PENINSULA THIS
MORNING. THIS FEATURE IS ALREADY GENERATING CONVECTION OVER THE
FLORIDA KEYS. THE SHORT TERM HIGH RESOLUTION MODELS HOWEVER DO NOT
HAVE A GOOD HANDLE ON WHAT EFFECTS THIS WILL HAVE FOR SOUTH FLORIDA
ESPECIALLY PARTICULARLY FOR TODAY. THE LOCALLY RUN WRF DID NOT
INITIALIZE WELL AT ALL AND IGNORES MUCH OF THE ONGOING CONVECTION.
THE HRRR DEPICTS THE AREA SHIFTING EAST DURING THE COURSE OF THIS
MORNING AND THIS SEEMS THE MOST REASONABLE GIVEN THE LATEST RADAR
AND SATELLITE ANIMATIONS. THE REAL DILEMMA IN TODAY`S FORECAST IS
JUST HOW MUCH DESTABILIZATION WILL OCCUR CONSIDERING THE EXTENSIVE
MID AND HIGH CLOUD COVER. GIVEN THE UNCERTAINTIES BUT THE FACT THAT
WE ARE BEING INFLUENCED BY A BROAD CYCLONIC FLOW ALOFT WITH 500 MB
TEMPERATURES OF AROUND -11C WILL SUPPORT MODEST INSTABILITY. IN
ADDITION, THE PWAT FROM THE 00Z MFL SOUNDING IS AT 1.87 INCHES WHICH
IS NEAR THE MAXIMUM FOR LATE APRIL WHICH SHOWS THE CHANCE FOR
LOCALLY HEAVY RAINFALL TO OCCUR. THEREFORE, ANY SUNSHINE THAT CAN
OCCUR TODAY WILL PROVIDE SUFFICIENT LIFT WITH SOME CHANCE FOR STRONG
WIND GUSTS AND SMALL HAIL ALONG WITH THE THREAT FOR LIGHTNING.
THE MID LEVEL AND SURFACE TROUGHS WILL SHIFT SOUTH AND EAST OF THE
PENINSULA BY THIS EVENING AS THEY GET KICKED OUT BY A DEEPENING
TROUGH INTO THE CENTRAL PLAINS STATES. THIS WILL ALSO BUILD A RIDGE
ACROSS THE AREA WITH A MUCH DRIER AND MORE STABLE ATMOSPHERE. SO A
MUCH QUIETER WEATHER PATTERN IS EXPECTED BY TUESDAY AND WEDNESDAY.
THAT BEING SAID, THE MENTION OF THUNDER ON TUESDAY HAS BEEN TAKEN
OUT OF THE GRIDS WITH FORECAST SOUNDINGS INDICATING PWAT DROPPING
TO LESS THAN AN INCH AND A QUARTER WITH VERY DRY ABOVE 5-10 K FEET.
.LONG TERM (WEDNESDAY NIGHT THROUGH SUNDAY)...
LOOKING AHEAD TO THE END OF THE WEEK AND THE UPCOMING WEEKEND, MUCH
OF THE PERIOD WILL BE IN A BENIGN WEATHER PATTERN WITH MID LEVEL
RIDGING AND SURFACE HIGH PRESSURE STRETCHING ACROSS SOUTH FLORIDA.
ANOTHER WEAKENING COLD FRONT WILL MOVE INTO NORTH FLORIDA BY LATE
THURSDAY OR FRIDAY AND THEN RAPIDLY BECOMES DIFFUSE. SO LITTLE
CHANCE FOR RAINFALL AFTER TODAY THROUGH THE FORECAST PERIOD.
&&
.MARINE...
A NORTHEAST SWELL WILL BEGIN TO AFFECT THE ATLANTIC WATERS OFF OF
THE PALM BEACH COUNTY COAST THIS AFTERNOON AND CONTINUE THROUGH
LATE TONIGHT. THIS WILL RESULT IN ROUGH WATERS AND A SCA HAS BEEN
ISSUED FOR THIS REASON. OTHER THAN THAT, AN UPPER LEVEL
DISTURBANCE ALONG WITH A SURFACE TROUGH WILL MOVE ACROSS THE SOUTH
FLORIDA WATERS TODAY WITH NUMEROUS SHOWERS AND THUNDERSTORMS. SOME
OF THE STRONGER STORMS MAY PRODUCE STRONG WIND GUSTS. HIGH
PRESSURE WILL RETURN TO THE REGION TONIGHT AND CONTINUE THROUGH
THE END OF THE WEEK.
&&
.FIRE WEATHER...
THE RELATIVE HUMIDITY WILL REMAIN WELL ABOVE CRITICAL LEVELS
THROUGH MID WEEK AS HIGH PRESSURE BUILDS BACK ACROSS SOUTH FLORIDA
TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 81 67 83 69 / 80 30 10 -
FORT LAUDERDALE 81 72 84 74 / 70 30 10 -
MIAMI 83 71 86 73 / 70 30 10 -
NAPLES 82 67 88 67 / 70 20 10 -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 2 PM THIS AFTERNOON
TO 5 AM EDT TUESDAY FOR COASTAL WATERS FROM JUPITER INLET
TO DEERFIELD BEACH, FL OUT 20 NM-WATERS FROM JUPITER INLET
TO DEERFIELD BEACH, FL EXTENDING FROM 20 NM TO 60 NM.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...23/SK
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
315 AM EDT MON APR 22 2013
...ONE MORE UNSETTLED DAY BEFORE DRIER CONDITIONS ARRIVE FOR
MIDWEEK...
.SYNOPSIS
07Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS BROAD MID/UPPER LEVEL
TROUGHING IN PLACE OVER THE SOUTHEASTERN CONUS. WEAK SHORTWAVE
IMPULSE IS CURRENTLY PASSING TO OUR NORTH EARLY THIS MORNING WITHIN
THE MAIN FLOW...WITH ANOTHER WEAK IMPULSE NOT FAR BEHIND AND PROGGED
TO PASS THROUGH LATER TODAY. PLENTY OF MID/UPPER LEVEL MOISTURE SEEN
IN WV IMAGERY OVER THE PENINSULA...WITH A SHARP GRADIENT IN THE
MOISTURE BEGINNING TO ERODE SOUTHWARD FROM THE BIG BEND. DEEP LAYER
QG FORCING ASSOCIATED WITH THE PASSING SHORTWAVE ALONG WITH A
COUPLED UPPER JET PATTERN OVERHEAD HAVE PROVIDED AMPLE LIFT TO
SUPPORT WIDESPREAD SHOWERS/ISOLATED STORMS EARLY THIS MORNING FROM
THE I-4 CORRIDOR SOUTHWARD. SHOWERS HAVE BEEN MORE SPARSE FURTHER
NORTH THROUGH THE NATURE COAST AS THE DRIER AIR IS TRYING TO ARRIVE.
AT THE SURFACE...FORECAST AREA RESIDES BETWEEN AN OLD
QUASI-STATIONARY FRONTAL BOUNDARY OVER THE SOUTHERN FL
PENINSULA...AND STRONG HIGH PRESSURE RIDGING DOWN THE ATLANTIC
SEABOARD INTO GA/AL. LARGE AREA OF WIDESPREAD RAIN FROM TAMPA
SOUTHWARD CONTINUES TO WEAKEN ON REGIONAL RADARS...HOWEVER EVEN IN
ITS WAKE...RESIDUAL LIFT AND MOISTURE WILL KEEP THE CHANCE OF
ADDITIONAL SHOWER DEVELOPMENT IN THE FORECAST AT JUST ABOUT ANY
TIME.
&&
.SHORT TERM (TODAY THROUGH WEDNESDAY)...
TODAY...
EXPECTING A GENERALLY UNSETTLED DAY IN TERMS OF SHOWERS AND ISOLATED
STORMS FOR AT LEAST THE SOUTHERN 2/3RDS OF THE FORECAST AREA. THE
FURTHER NORTH ONE TRAVELS FROM THE I-4 CORRIDOR...DEEP LAYER
MOISTURE WILL BE DECREASING QUICKLY...AND SHOULD LIMIT THE DEGREE OF
OVERALL SHOWER ACTIVITY. WILL SHOW CHANCE 30-50% POPS FOR MAINLY
MORNING/EARLY AFTERNOON SHOWERS UP TOWARD CITRUS/LEVY COUNTIES.
ALONG THE I-4 CORRIDOR AND ESPECIALLY SOUTHWARD...NUMEROUS SHOWERS
AND ISOLATED STORMS WILL REMAIN IN THE FORECAST. THIS CONVECTIVE
ACTIVITY WILL LIKELY PEAK IN THE AFTERNOON/EARLY EVENING DUE TO THE
APPROACH OF THE NEXT SHORTWAVE AND ASSOCIATED SYNOPTIC SUPPORT/QG
FORCING ALONG WITH RETAINING A COUPLET JET DIVERGENT PATTERN...AND
THE DIURNAL HEATING MAXIMUM. WILL SHOW 60-70% POPS FOR THESE
CENTRAL/SOUTHERN ZONES...WITH BETTER RAIN CHANCES LIKELY SHIFTING
SOMEWHAT EAST AND SOUTH BY LATE DAY FOLLOWING THE RETREAT OF THE
DEEP LAYER MOISTURE. EXPECTING A MOSTLY CLOUDY DAY...HOWEVER
THE COLUMN POTENTIAL IS QUITE HIGH IN TERMS OF TEMPERATURES...AND
THEREFORE EVEN A FEW SUNNY BREAKS WILL HELP TEMPS REACH THE LOWER
80S. WILL SHOW THESE NUMBERS FOR HIGH TEMPERATURES...HOWEVER ANY
AREAS WITH EARLY OR ROBUST CONVECTIVE COVERAGE TODAY MAY VERY LIKELY
BE HELD IN THE 70S.
TONIGHT...
ANY EVENING SHOWERS SOUTH AND EAST OF THE TAMPA BAY AREA SHOULD END
RATHER QUICKLY AFTER SUNSET AS SHORTWAVE SUPPORT EXITS AND TAKES
THE SURFACE BOUNDARY EAST INTO THE ATLANTIC. AT THE SAME
TIME...SUBSIDENCE BEHIND THIS IMPULSE WILL HELP TO FURTHER ADVECT A
DRY MID/UPPER LEVEL COLUMN OVER OUR HEADS. AT THE SURFACE... THE
RIDGING THAT EXTENDS DOWN THE LEE OF THE APPALACHIANS WILL BUILD
SOUTHWARD INTO THE NORTHERN/CENTRAL FL PENINSULA. ALTHOUGH THE DEEP
LAYER MOISTURE WILL BE GONE...TIME-HEIGHT AND CROSS SECTION ANALYSIS
SHOWS THAT THERE WILL BE PLENTY OF LOW LEVEL MOISTURE TRAPPED UNDER
700MB. THE VERY DRY COLUMN OVERTOP THIS MOISTURE AND THE NE FLOW
SUGGEST THE DEVELOPMENT OF AREAS OF LOW LEVEL STRATUS OVERNIGHT.
THESE CLOUDS WILL HAVE LITTLE IMPACT ON OUR SENSIBLE WEATHER...BUT
WOULD HAVE IMPACTS FOR AVIATION.
TUESDAY/WEDNESDAY...
SHORTWAVE ENERGY EJECTING EASTWARD ACROSS THE CENTRAL PORTION OF THE
NATION WILL FORCE DOWNSTREAM MID/UPPER LEVEL RIDGE AMPLIFICATION
OVER THE EASTERN GULF AND FL PENINSULA THROUGH THE PERIOD. THIS
RIDGING WILL EXIST OVERTOP SURFACE HIGH PRESSURE THAT WILL FIRMLY BE
IN CONTROL OF THE REGION. THE STACKED RIDGING AND GENERALLY DRY
COLUMN ABOVE 850MB WILL RESULT IN A RAIN-FREE FORECAST INTO THE
MIDDLE OF THE WEEK...ALONG WITH SEASONABLE DAYTIME TEMPERATURES...
AND SEASONABLY COOL OVERNIGHT TEMPS. HIGH TEMPS TUESDAY AND
WEDNESDAY SHOULD REACH INTO THE 80S. LOW TEMPS TUESDAY NIGHT FROM
THE LOW/MID 60S SOUTH...TO THE MID/UPPER 50S NORTH.
&&
.LONG TERM (THURSDAY THROUGH NEXT SUNDAY)...
UPPER LEVEL RIDGING GENERALLY DOMINATES THE GULF OF MEXICO AND FL
THROUGH THE END OF THE WORK WEEK AS AN UPPER LEVEL TROUGH MOVES
ACROSS THE EASTERN STATES. THIS TROUGH PUSHES A FRONTAL BOUNDARY
INTO THE SE U.S THURSDAY THEN NORTHERN FL FRI WHERE IT WASHES OUT. A
SURFACE HIGH MOVES FROM THE EASTERN PLAINS TO THE OHIO
VALLEY...BRIDGING THE BOUNDARY BY FRI.
OVER THE WEEKEND THE UPPER RIDGE SLIDES ACROSS FL AS A UPPER TROUGH
MOVES INTO THE SOUTHERN PLAINS AND WESTERN GULF WITH ANOTHER FRONTAL
BOUNDARY SAGGING IN ALONG THE WEST/CENTRAL GULF COAST. THE OHIO
VALLEY SURFACE HIGH MOVES ACROSS THE EASTERN SEABOARD TO THE
ATLANTIC WITH LOW LEVEL FLOW ACROSS THE AREA VEERING FROM NORTHEAST
TO EAST AND SOUTHEAST.
THE UPPER LEVEL RIDGING AND THE BOUNDARY WASHING OUT TO THE NORTH
WILL KEEP ANY RAIN CHANCES OUT OF THE FORECAST THROUGH SAT. BY SUN
THE UPPER RIDGE EAST OF THE STATE AND INCREASING MOISTURE ON EAST
AND SE LOW LEVEL FLOW...WITH A GRADIENT RELAXED ENOUGH FOR AN
AFTERNOON SEA BREEZE...COMBINE TO PROVIDE A SLIGHT CHANCE OF
THUNDERSTORMS. TEMPERATURES WILL RUN NEAR TO SLIGHTLY ABOVE
NORMAL.
&&
.MARINE...
A STRONG RIDGE OF HIGH PRESSURE BUILDS SOUTH INTO THE EASTERN GULF
OF MEXICO LATER TODAY AND TONIGHT. EASTERLY WINDS WILL INCREASE BY
THIS EVENING IN ASSOCIATED WITH THIS FEATURE AND LIKELY RESULT IN A
PERIOD OF CAUTIONARY WINDS INTO TUESDAY MORNING...ESPECIALLY FOR
MARINE AREAS ADJACENT TO TAMPA BAY AND NORTHWARD. THE HIGH CENTER TO
THE NORTH OF THE AREA TUESDAY NIGHT WILL AGAIN SET UP FAVORABLE
CONDITIONS FOR A NOCTURNAL EASTERLY WIND SURGE TO CAUTIONARY
LEVELS...WHICH SHOULD LINGER INTO EARLY WEDNESDAY MORNING. A
WEAKENING GRADIENT IS THEN EXPECTED TO KEEP WINDS AND SEAS BELOW
HEADLINE CRITERIA FOR THE LATER PORTION OF THE WEEK.
&&
.AVIATION...
LARGE AREA OF CLOUDINESS WITH SHRA/RA WILL KEEP TAF/S MVFR TO LCL
IFR. ANTICIPATE VFR RETURN AFTER SUNRISE WITH SOME TSRA IN THE
AFTERNOON.
&&
.FIRE WEATHER...
ABUNDANT LOW LEVEL MOISTURE AND SCATTERED TO NUMEROUS SHOWERS WILL
KEEP RELATIVE HUMIDITY VALUES WELL ABOVE CRITICAL LEVELS TODAY. A
DRIER AIRMASS WILL ARRIVE FOR TUESDAY AND WEDNESDAY WHEN A FEW
INLAND LOCATIONS MAY BRIEFLY SEE RELATIVE HUMIDITY VALUES DROP INTO
THE MIDDLE 30S DURING THE AFTERNOON HOURS. NO RED FLAG CONDITIONS
ARE CURRENTLY EXPECTED THROUGH THE MIDDLE OF THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 83 67 85 65 / 60 10 10 10
FMY 85 66 88 64 / 60 20 10 10
GIF 85 63 87 61 / 70 10 10 10
SRQ 82 66 85 63 / 60 10 10 10
BKV 82 62 85 57 / 60 10 10 10
SPG 82 69 84 68 / 60 10 10 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM/AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS DULUTH MN
1210 AM CDT MON APR 22 2013
.AVIATION...06Z TAFS.
IFR/MVFR CEILINGS COVERED MOST OF THE NORTHLAND THIS EVENING...WITH
DRIZZLE/LIGHT RAIN OR LIGHT SNOW STILL FALLING OVER PORTIONS OF FAR
EASTERN MINNESOTA AND NORTHWEST WISCONSIN. THE PRECIPITATION SHOULD
DIMINISH THROUGH THE REST OF THE NIGHT. CEILINGS WERE STARTING TO
RISE OVER THE WESTERN ZONES...WITH A LARGE CLEAR AREA OVER PORTIONS
OF NORTHWEST MINNESOTA/EASTERN NORTH DAKOTA AND SOUTHEAST MANITOBA.
WE EXPECT THIS TO EXPAND SOUTHEAST OVERNIGHT.
ANOTHER SPRING STORM WILL THEN TAKE AIM ON THE NORTHLAND AS EARLY AS
MONDAY AFTERNOON...BUT MORE SO MONDAY NIGHT. IT WILL BRING LOWER
CEILINGS BACK INTO THE REGION...AND REDUCE VISIBILITIES IN SNOW OVER
MUCH OF NORTHWEST WISCONSIN AND OVER EASTERN MINNESOTA.
&&
.PREV DISCUSSION... /ISSUED 1025 PM CDT SUN APR 21 2013/
UPDATE...
RADAR SHOWS THE MAIN PRECIPITATION AREA MOVING THROUGH FAR EASTERN
MINNESOTA AND NORTHWEST WISCONSIN...AND IT WAS DECREASING IN
INTENSITY. DRIZZLE OR LIGHT SNOW WAS STILL OCCURRING FROM COOK
THROUGH THE TWIN PORTS TOWARD SIREN...BUT THIS SHOULD BE
DIMINISHING AS WELL.
LOOKING AHEAD...THE LATEST NAM IS INDICATING A GREATER THREAT FOR
SOME SIGNIFICANT SNOW OVER A PORTION OF OUR CWA...MAINLY OVER
NORTHWEST WISCONSIN. EVEN AREAS AS FAR WEST AND NORTH AS
BRAINERD...THE TWIN PORTS AND THE NORTH SHORE AREA WILL SEE SOME
ACCUMULATING SNOW. HOW MUCH IS STILL IN QUESTION...AS WE WANT TO
SEE THE GFS/ECMWF BEFORE JUMPING ON HEADLINES. THE NAM DOES SHOW
IMPRESSIVE FGEN OVER OUR CWA...ALONG THE TIGHT THERMAL GRADIENT. IT
DOES LOOK LIKELY WE`LL NEED AT LEAST SOME ADVISORIES...AND IF THE
NAM IS CORRECT...WARNINGS MAY ALSO BE NEEDED ACROSS MUCH OF OUR NORTHWEST
WISCONSIN ZONES. THERE WILL BE A TRANSITION TO MIXED PRECIPITATION OR
LIQUID OVER PORTIONS OF PRICE/SAWYER/IRON COUNTIES WHICH WILL
FURTHER COMPLICATE SNOW AMOUNTS THERE. STAY TUNED TO LATER
FORECASTS AND DISCUSSIONS ON THIS DEVELOPING SPRING STORM.
PREV DISCUSSION... /ISSUED 642 PM CDT SUN APR 21 2013/
UPDATE...
RAIN AND SNOW WAS OCCURRING OVER A GOOD PORTION OF THE EASTERN
HALF OF MINNESOTA INTO WESTERN WISCONSIN THIS EVENING. SNOW WAS
DOMINANT ACROSS THE FAR NORTHERN PORTION OF OUR CWA...AND WAS
OCCURRING AT KDLH. THE RAP AND NAM BOTH INDICATE WET BULB ZERO
LEVELS SHOULD HAVE INCREASED QUITE A BIT BETWEEN 21Z AND 00Z
OVER THE SOUTHERN HALF OF THE CWA. HOWEVER...KDLH REMAINS MOSTLY
SNOW BUT WE DO EXPECT A MIX TO OCCUR AS PRECIP RATES DIMINISH. WE
ADJUSTED PRECIP TYPE/POPS A BIT EARLIER THIS EVENING...AND WILL DO
SO AS THE PRECIP DIMINISHES FROM WEST TO EAST OVERNIGHT.
AVIATION...00Z TAFS
IFR OR MVFR CONDITIONS COVERED THE NORTHLAND THIS EVENING...AND
THAT IS EXPECTED TO CONTINUE OVERNIGHT. AN AREA OF SNOW/RAIN
COVERED MOST OF NORTHEAST MINNESOTA AND NORTHWEST WISCONSIN...WITH
RADAR SHOWING THE PRECIPITATION DIMINISHING FROM WEST TO EAST. THAT
TREND WILL CONTINUE OVERNIGHT...WITH MOST OF THE PRECIPITATION
EXITING EASTERN MINNESOTA BETWEEN 03-06Z...AND NORTHWEST
WISCONSIN BETWEEN 05-08Z. IFR OR MVFR CONDITIONS WILL REMAIN...AND
WE EXPECT IMPROVEMENT MONDAY MORNING...BEFORE YET ANOTHER SYSTEM
WILL BRING LOWER CEILINGS AND MORE SNOW TO THE NORTHLAND. THE BEST
CHANCE FOR ADDITIONAL SNOW WILL BE OVER EAST CENTRAL MINNESOTA AND
NORTHWEST WISCONSIN OVER OUR CWA.
PREV DISCUSSION... /ISSUED 306 PM CDT SUN APR 21 2013/
SHORT TERM.../NOW - MONDAY/
THROUGH TONIGHT...THE FOCUS FOR THIS FORECAST IS THE PCPN
ASSOCIATED WITH AN APPROACHING COLD FRONT THAT IS ALREADY MOVING
INTO THE WESTERN FORECAST AREA. THE NORTHLAND IS EXPECTED TO HAVE
THIS PCPN MOVE THROUGH THE REGION FROM WEST TO EAST THROUGH
TONIGHT. WHILE ARE MOSTLY FORECASTING RAIN WITH LITTLE TO NO SNOW
ACCUMULATION...THERE IS STILL SOME UNCERTAINTY AS TO PCPN TYPE AND
SNOWFALL ACCUMULATION SINCE THE TEMPERATURES ACROSS THE NORTHLAND
ARE ONLY IN THE MID TO UPPER 30S. BASED ON MODEL SOUNDINGS...THE
SNOW IS DEFINITELY FALLING AS SNOW ALOFT...BUT THEN ENCOUNTERING
MELTING CLOSE TO THE SURFACE. IT MAY BE THAT THE PCPN BEGINS AS
RAIN...BUT AS THE TEMPERATURES FALL WITH THE PCPN...TRANSITIONS TO
SNOW. FOR AREAS THAT DO GET SNOW...THERE IS THE QUESTION OF
ACCUMULATION BECAUSE THE TEMPERATURES IN THE LOW TO MID 30S MAY
MELT MUCH OF WHAT FALLS. I AM ONLY REASONABLY CONFIDENT THAT THE
ARROWHEAD WILL SEE ANY SIGNIFICANT ACCUMULATION...PERHAPS UP TO 2
INCHES...DUE TO THE LOWER TEMPERATURES. I INCREASED THE SNOWFALL
FORECAST ACROSS THE REST OF THE NORTHLAND TOO...BUT GENERALLY GAVE
A HALF INCH OR LESS OF ACCUMULATION. WE WILL NEED TO MONITOR THE
PCPN OVER THE NEXT FEW HOURS AND SEE HOW QUICKLY THE PCPN
TRANSITIONS TO SNOW. IT MAY BE SOME AREAS GET A SURPRISE 1 OR 2
INCHES OF SNOW. THE COLD FRONT...CURRENTLY IN THE EASTERN
DAKOTAS...WILL MOVE THROUGH THE NORTHLAND THIS EVENING. THERE
SHOULD BE SOME PARTIAL CLEARING ACROSS THE FORECAST AREA IN THE
WAKE OF THE FRONT LATE TONIGHT. OVERNIGHT LOWS WILL RANGE FROM THE
MID 30S ACROSS THE FAR SE FORECAST AREA TO THE MID TO UPPER 20S
ACROSS THE WEST AND NORTH.
MONDAY...THE COLD FRONT WILL STALL FROM IOWA TO UPPER PENINSULA
MICHIGAN AS A LOW PRESSURE CENTER BEGINS TO DEVELOP ALONG THE
FRONT IN THE MISSOURI AREA. THE MODELS CONTINUE TO INDICATE PCPN
ON THE WESTERN SIDE OF THE FRONT WILL BEGIN TO SPREAD FROM EASTERN
SOUTH DAKOTA AND SOUTHERN MINNESOTA INTO NE MINNESOTA AND NW
WISCONSIN DURING THE AFTERNOON. THE MODELS AND SOUNDINGS SEEM TO
FAVOR SNOW...BUT THE SURFACE TEMPERATURES IN THE UPPER 30S TO MID
40S WILL PROBABLY RESULT IN SOME MELTING TO RAIN DURING THE
AFTERNOON...ESPECIALLY FOR NW WISCONSIN. HOWEVER...THIS WILL BE
ANOTHER TRICKY SITUATION THAT WILL NEED TO BE LOOKED INTO MORE
BECAUSE IT COULD JUST AS EASILY MEAN IN UP TO A FEW INCHES OF SNOW
ACCUMULATION FOR SOME PARTS OF THE FORECAST AREA DURING THE
AFTERNOON. THE PCPN WILL LIKELY THAN TRANSITION TO SNOW MONDAY
EVENING.
LONG TERM.../MONDAY NIGHT - SATURDAY/
SNOW WILL LIKELY BE ONGOING AT THE START OF THE PERIOD...AS
FAVORABLE JET DYNAMICS COME INTO PLAY ACROSS THE NORTHLAND. STRONG
ASCENT IN THE RIGHT ENTRANCE REGION OF THE 115 KNOT JET SEGMENT
MOVING ACROSS MN AND INTO ONTARIO WILL AID IN PROVIDING PLENTY OF
FORCING FOR WIDESPREAD PRECIPITATION ACROSS PORTIONS OF MN AND WI.
THE MODELS GENERALLY SHOW A GREAT DEAL OF UPPER LEVEL DIVERGENCE AS
ANOTHER STRONG JET SEGMENT ALSO LIFTS INTO THE WESTERN GREAT LAKES
FROM THE PLAINS. THE NAM...GFS AND ECMWF ALL SHOW A STRONG
BAROCLINIC ZONE ACROSS SE MN AND MUCH OF THE NW 1/2 OF WI...ALONG
WITH A STRONG LLJ OF 30-40 KT. COULD BE A FEW INCHES OF SNOW ACROSS
NE MN AND SEVERAL INCHES OF SNOW ACROSS NW WI. A DISTINCT WARMING
TREND WILL THEN TAKE PLACE ACROSS THE REGION...ALTHOUGH IT WILL BE A
BIT UNSETTLED FOR THE REMAINDER OF THE EXTENDED AS A FEW LOW
PRESSURE SYSTEMS WILL MOVE THROUGH THE REGION.
&&
.POINT TEMPS/POPS...
DLH 41 26 41 23 / 50 60 20 10
INL 39 20 39 22 / 0 10 10 10
BRD 40 24 41 23 / 40 20 10 10
HYR 46 28 42 23 / 60 80 30 10
ASX 45 31 41 25 / 40 80 40 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...GSF
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
334 AM CDT MON APR 22 2013
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 330 AM CDT MON APR 22 2013
FORECAST CHALLENGES CONCERN SNOW CHANCES ACROSS THE FAR SOUTH
TODAY AND TEMPERATURES. MODELS OVERALL IN GOOD AGREEMENT THROUGH
THE SHORT TERM AND WILL USE BLEND.
FOR TODAY FAR SOUTHERN FA WILL BE IN ENTRANCE REGION OF PASSING UPPER
JET MAXIMA. MAIN BAROCLINIC ZONE WELL SOUTH OF FA HOWEVER LOWER
CONDENSATION PRESSURE DEFICITS CLIP FAR SOUTHERN FA. MODELS HAVE
INITIALIZED PRETTY WELL WITH W SD SNOW BAND. NORTHERN EXTENT
SOMEWHAT IN QUESTION WITH RADAR COVERAGE HOWEVER HETTINGER AT THIS
POINT DRY SO SNOW SHOULD BE RIGHT ALONG OR JUST SOUTH OF BORDER.
BASED ON GOOD MODEL AGREEMENT FAR SOUTH WILL BE ON NORTHERN FRINGE
OF PCPN. WILL FOLLOW HIGH RESOLUTION RAP MODEL SOLUTION AND
INCREASE POPS ALONG ND/SD/MN BORDER AREA TODAY. STEADY COLD
ADVECTION AND SOME DEGREE OF CLOUD COVER WILL REALLY LIMIT ANY
TEMPERATURE RECOVERY. DVL BASIN MAY STRUGGLE TO GET TO
FREEZING/MELTING VALUES.
HIGH PRESSURE WILL BUILD INTO CENTRAL/NORTHERN PLAINS TONIGHT.
WITH LIGHT WINDS/MINIMAL CLOUD COVER AND COLD COLUMN WILL RESULT
IN COLD TEMPERATURES WITH RECORD LOWS POSSIBLE.
COLUMN WARMS SLIGHTLY TUESDAY AND ALONG WITH SOLAR AND MODEST
WESTERLY FLOW TEMPERATURES SHOULD BE A BIT WARMER.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM CDT MON APR 22 2013
MODEST TEMPERATURE RECOVERY WILL CONTINUE INTO MIDWEEK HOWEVER
WITH TEMPERATURES DROPPING BLO FREEZING AT NIGHT SNOW MELT PROCESS
WILL CONTINUE TO BE SLOW. NEXT WAVE TO SWING THROUGH BROAD CENTRAL
PLAINS MID LEVEL TROUGH WEDNESDAY HOWEVER LOOKS TO BE A LIGHT PCPN
EVENT.
THURSDAY TO SUNDAY...CONFIDENT IN A GENERALLY DRY PERIOD WITH
TEMPERATURES MODERATING TOWARD NEAR NORMAL BY NEXT WEEKEND. NW FLOW
ALOFT WITH SFC RIDGE AXIS IS EXPECTED TO DEPART THE REGION THURSDAY
WITH MORE ZONAL 500MB FLOW AND SOUTHERN RETURN FLOW ALLOWING FOR
850MB TEMPS TO WARM FROM 5 TO 10 BLO C THURS MORNING TO 5 TO 10
ABOVE BY FRI MORNING. WEAK SW AND FROPA WILL BRING SCHC OF SHRA FRI
AFTN. ANOTHER PERIOD OF WAA IS EXPECTED TO LIFT INTO THE REGION
SATURDAY AND SUNDAY WITH WEAK 500MB RIDGING WITH 850MB TEMPS PUSHING
INTO THE 10 TO 15 C RANGE.
HOW THESE TEMPS WILL INTERACT WITH SNOWPACK...ESPECIALLY IN THE
DEEPER SNOWS OF THE DEVILS LAKE BASIN AND NORTHERN RED RIVER
VALLEY...CAUSES SOME UNCERTAINTY IN THE OVERALL EXTENT OF THE WARM
UP. IF MIXING IS LESS THAN EXPECTED FOG WOULD BE LIKELY TO DEVELOP
OVERNIGHT LIMITING SOLAR INFLUENCES THE NEXT DAY OF THE WARM UP.
NONETHELESS LIKELY THAT THE GRADUAL SNOW MELT ENDS WITH OVERNIGHT
TEMPS ABOVE FREEZING BEGINNING FRIDAY NIGHT AND THRU THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1138 PM CDT SUN APR 21 2013
CENTRAL TAF SITES HAVE CLEARED OFF WITH ONLY SOME CIRRUS
REMAINING. KBJI REMAINS MVFR AND SOME STRATUS WITH 2500-3500 FT
CIGS HAS STARTED TO MOVE INTO THE KDVL REGION. THIS SHOULD SPREAD
SOUTH AND EAST OVERNIGHT...BUT COVERAGE IS BROKEN AND CLEAR SPOTS
WILL CONTINUE. INCLUDED SOME TEMPO GROUPS FOR VARIATION BETWEEN
VFR AND MVFR CONDITIONS WITH THE PARTIAL STRATUS COVERAGE. THERE
COULD BE SOME BREAK IN THE CIGS THIS MORNING BUT STRATOCU WILL
REDEVELOP AND BRING CIGS AROUND 3500-5000 FT FOR AFTERNOON. MORE
WIDESPREAD CLEARING LATE IN THE PERIOD.
&&
.HYDROLOGY...
ISSUED AT 330 AM CDT MON APR 22 2013
RIVER FLOOD WARNINGS IN EFFECT FOR SABIN ALONG THE S BR BUFFALO
RIVER...DILWORTH ALONG THE BUFFALO RIVER...AND WAHPETON ALONG THE
RED RIVER. DESPITE THE RELATIVELY COOL TEMPS...LOCALIZED RUNOFF
ALONG SOME OF THE MN TRIBS...INCLUDING ALONG THE BUFFALO... HAS
LEAD TO INCREASED RIVER STAGES. SIMILARLY...GRADUAL RISES HAVE
BEEN NOTED ALONG THE MAINSTEM RED AS WATER BEGINS TO MAKE ITS WAY
INTO THE SYSTEM. THIS IS ESPECIALLY TRUE ACROSS THE SOUTH TOWARDS
WAHPETON...WHERE MINOR FLOOD STAGE WILL LIKELY BE APPROACHED BY
EARLY THIS WEEK. COOLER TEMPS THROUGH THE MIDDLE OF THE WEEK WILL
LIMIT THE SNOWMELT PROCESS WITH WELL BELOW FREEZING TEMPS AT
NIGHT. IT APPEARS MORE SIGNIFICANT WARMING WILL OCCUR BY LATE THIS
WEEK. THIS WILL LEAD TO INCREASED SNOWMELT RUNOFF...AND MORE RAPID
RIVER RESPONSES BY NEXT WEEKEND. SOME UNCERTAINTY EXISTS REGARDING
THE DEGREE AND TIMING OF THE WARMER TEMPS...WHICH WILL AFFECT HOW
QUICKLY THE RIVERS RESPOND. NO SIGNIFICANT PRECIP EVENTS ARE
EXPECTED AT THIS TIME THROUGH THE COMING WEEK.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...VOELKER
LONG TERM...JK
AVIATION...JR
HYDROLOGY...VOELKER
AREA FORECAST DISCUSSION
NWS SPOKANE WA
908 PM PDT Sun Apr 21 2013
.SYNOPSIS...
A cold front will generate showers over the eastern Columbia basin
and light accumulating snow in the mountains of the Idaho
Panhandle this evening. Monday morning will be cold with
temperatures well below freezing region-wide. A warming and
drying trend is expected this week. By Thursday and Friday,
temperatures will be 8 to 10 degrees above average.
&&
.DISCUSSION...
Evening update: Shower activity along today`s cold front is
beginning to wane and push south of the region. As of 830PM...the bulk
of the showers were south of a line from Clarkia to Walla Walla.
This should be out of the region by midnight. Looking upstream, a
second batch of showers has redeveloped over the Northern Idaho
Panhandle between Sandpoint and Porthill, associated with one more
vort max within the cusp of the trof. HRRR has initialized this
activity well and suggest it will struggle to make it south of
I-90 but not I totally buy into this idea given similar
atmospheric conditions. As such, we have added a slight chance for
rain/snow showers along the spine of the WA/ID border.
Snow shower activity has also ceased at Lookout Pass and the main
travel threat at this time will be slick to icy roadways. I will
wait to see the evolution of this band of showers dropping in from
the north before totally cancelling.
Temperatures will be tricky tonight. There is a distinct boundary
of dry continental air from roughly Colville to Omak in which
dewpoints are in the teens to 20s and generally in the upper 20`s
to 30`s south of the boundary. All guidance suggest the drier air will
continue to seep southward with most locations drying out into the
20`s overnight. What makes the forecast difficult is determining
whether winds will remain breezy enough to keep temperatures from
bottoming out, especially at locations like Wenatchee and Moses
Lake which begin growing season tomorrow (4/23). Most guidance
cool these locations between 32-35F so a hard freeze is not
anticipated but outlying areas may dip closer to 30F and any
persons with sensitive plants may want to take proper precautions.
Given these locations were below freezing four nights ago and
growing season starts tomorrow, we will hold off on any freeze
highlights this evening. /sb
&&
.AVIATION...
00Z TAFS: A cold front laying from KEAT to KMLP at 00z will move
south through this evening into central ID by 06Z tonight.
Numerous valley rain and mountain snow showers along the front
will impact the KPUW and KLWS TAF sites through 06Z...with
scattered and decreasing showers from the north at the KGEG area
TAF sites until 02-03Z. MVFR Ceilings will be common with these
showers. Behind this front very dry low level air will move into
the region and bring clearing skies with VFR conditions to the
entire region after 06Z tonight and lasting through 00Z Tuesday.
Breezy north to northeast winds will impact the KEAT...KMWH and
KGEG through 15Z-18Z Monday as this dry dense air moves through
northern mountain gaps and fills the basin. /MJF
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 28 53 32 57 35 62 / 0 0 0 10 0 0
Coeur d`Alene 27 52 28 57 32 61 / 20 0 0 20 10 0
Pullman 28 51 29 56 33 62 / 20 0 0 0 0 0
Lewiston 34 57 32 62 37 68 / 70 10 0 0 0 0
Colville 28 59 28 63 33 66 / 0 0 0 20 10 0
Sandpoint 27 51 27 55 30 59 / 20 0 0 20 10 0
Kellogg 26 47 29 52 32 59 / 20 0 0 20 20 0
Moses Lake 31 61 32 67 37 70 / 10 0 0 0 0 0
Wenatchee 33 60 36 64 40 67 / 0 0 0 0 0 0
Omak 26 60 29 64 35 68 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory until 6 AM PDT Monday for Central
Panhandle Mountains.
WA...None.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
1006 AM EDT MON APR 22 2013
...A FEW STRONG STORMS POSSIBLE LATE THIS AFTERNOON INTO EARLY
THIS EVENING...
.UPDATE...
A MID LEVEL SHORT WAVE MOVED THROUGH SOUTH FLORIDA LAST NIGHT AND
WAS LOCATED OVER THE WESTERN ATLANTIC WATERS THIS MORNING. THIS
SHORT WAVE WILL CONTINUE TO MOVE EAST AWAY FROM SOUTH FLORIDA
THROUGH THE AFTERNOON HOURS TAKING THE SHOWERS AND THUNDERSTORMS
OVER THE LOCAL ATLANTIC WATERS WITH IT...AND ALLOWING FOR THE
SKIES TO BECOME PARTLY CLOUDY BY AFTERNOON. THIS WILL ALSO ALLOW
FOR TEMPERATURES TO WARM UP INTO THE MID 80S ALONG THE METRO AREAS
TO UPPER 80S OVER THE INTERIOR AREAS THIS AFTERNOON.
ANOTHER SHORT WAVE OVER EASTERN GULF OF MEXICO WILL ALSO MOVE EAST
AND THROUGH SOUTH FLORIDA THIS AFTERNOON INTO THIS EVENING...AS A
THROUGH OF LOW PRESSURE OVER SOUTH CENTRAL FLORIDA MOVES SOUTH
INTO THE LAKE OKEECHOBEE AREA. AT THE SAME TIME...BOTH THE EAST
AND WEST COAST SEA BREEZES WILL DEVELOP AND PUSH INLAND WITH THE
WEST COAST SEA BREEZE PUSHING ACROSS THE AREA. SO WILL KEEP THE
POPS LIKELY OVER MOST OF SOUTH FLORIDA FOR THIS AFTERNOON...EXCEPT
CHANCE OVER THE WEST COAST AREAS.
A FEW OF THE STORMS COULD EVEN BECOME STRONG OVER THE INTERIOR AND EAST
COAST METRO AREAS LATE THIS AFTERNOON INTO EARLY THIS EVENING
ESPECIALLY WHERE THE SEA BREEZES COLLIDE. THE PRIMARY IMPACTS WILL
BE FREQUENT LIGHTNING STRIKES...GUSTY WINDS...SMALL HAIL...AND
HEAVY RAINFALL.
A NORTHEAST SWELL OF 2 TO 4 FEET WILL ALSO CONTINUE TO WORK INTO
THE NORTHERN WATERS OF PALM BEACH COUNTY THIS AFTERNOON.
HOWEVER...THE WIND FLOW WILL BE FROM THE EAST TO SOUTH DIRECTION
AT 5 TO 10 KNOTS. THIS WILL ONLY ALLOW FOR THE SEAS TO BUILD UP TO
6 FEET THIS AFTERNOON INTO THIS EVENING. THEREFORE...THE SCA WILL
BE DROP AND A SCEC WILL BE PUT UP FOR THE WEST PALM BEACH WATERS
FOR THIS AFTERNOON INTO THIS EVENING.
REST OF THE FORECAST LOOKS GOOD AT THIS TIME AND NO OTHER CHANGES
ARE PLANNED.
&&
.UPDATE...54/BNB
.PREV DISCUSSION... /ISSUED 741 AM EDT MON APR 22 2013/
AVIATION...
A LOW PRESSURE TROUGH WILL CROSS THE REGION TODAY...BRINGING
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. WIDESPREAD ACTIVITY
THIS MORNING IMPACTING ATLANTIC WATERS WILL MOSTLY STAY
OFFSHORE...AND LATEST GUIDANCE HINTS AT FAIRLY LOW COVERAGE OF
PRECIPITATION THROUGH THE MORNING HOURS. THUS...NO PREVAILING
SHRA/TSRA IN 12Z TAFS. INSTEAD...VCSH THROUGH 18Z...THEN VCTS. LOW
STRATUS IMPACTING BROWARD AND MIAMI-DADE TERMINALS...BUT THIS SHOULD
BREAK AWAY BY 13-14Z...THEN VFR PREVAILS. TEMPORARY BUT SIGNIFICANT
RESTRICTIONS ARE POSSIBLE THROUGHOUT THE DAY...IN AND NEAR PCPN.
HIGH PRESSURE BUILDS IN TONIGHT...WITH CLEARING SKIES EXPECTED.
GENERAL EASTERLY FLOW AT AROUND 10 KTS TODAY...BECOMING NORTH
TONIGHT. GUSTY WINDS ARE POSSIBLE NEAR THUNDERSTORMS.
&&
PREV DISCUSSION... /ISSUED 328 AM EDT MON APR 22 2013/
SHORT TERM (TODAY THROUGH WEDNESDAY)...
THE GLOBAL MODELS ARE IN GENERAL AGREEMENT WITH THE OVERALL SYNOPTIC
SHORT TERM PATTERN IN DEPICTING A NEAR ZONAL FLOW ACROSS MUCH OF
SOUTHEASTERN STATES ALONG WITH A STATIONARY SURFACE FRONTAL TROUGH
ACROSS SOUTH CENTRAL FLORIDA. A FAST MOVING SOUTHERN STREAM MID
LEVEL TROUGH EMBEDDED WITHIN THIS FLOW IS CURRENTLY MOVING INTO THE
EASTERN GULF OF MEXICO AND WILL MOVE ACROSS THE PENINSULA THIS
MORNING. THIS FEATURE IS ALREADY GENERATING CONVECTION OVER THE
FLORIDA KEYS. THE SHORT TERM HIGH RESOLUTION MODELS HOWEVER DO NOT
HAVE A GOOD HANDLE ON WHAT EFFECTS THIS WILL HAVE FOR SOUTH FLORIDA
ESPECIALLY PARTICULARLY FOR TODAY. THE LOCALLY RUN WRF DID NOT
INITIALIZE WELL AT ALL AND IGNORES MUCH OF THE ONGOING CONVECTION.
THE HRRR DEPICTS THE AREA SHIFTING EAST DURING THE COURSE OF THIS
MORNING AND THIS SEEMS THE MOST REASONABLE GIVEN THE LATEST RADAR
AND SATELLITE ANIMATIONS. THE REAL DILEMMA IN TODAY`S FORECAST IS
JUST HOW MUCH DESTABILIZATION WILL OCCUR CONSIDERING THE EXTENSIVE
MID AND HIGH CLOUD COVER. GIVEN THE UNCERTAINTIES BUT THE FACT THAT
WE ARE BEING INFLUENCED BY A BROAD CYCLONIC FLOW ALOFT WITH 500 MB
TEMPERATURES OF AROUND -11C WILL SUPPORT MODEST INSTABILITY. IN
ADDITION, THE PWAT FROM THE 00Z MFL SOUNDING IS AT 1.87 INCHES WHICH
IS NEAR THE MAXIMUM FOR LATE APRIL WHICH SHOWS THE CHANCE FOR
LOCALLY HEAVY RAINFALL TO OCCUR. THEREFORE, ANY SUNSHINE THAT CAN
OCCUR TODAY WILL PROVIDE SUFFICIENT LIFT WITH SOME CHANCE FOR STRONG
WIND GUSTS AND SMALL HAIL ALONG WITH THE THREAT FOR LIGHTNING.
THE MID LEVEL AND SURFACE TROUGHS WILL SHIFT SOUTH AND EAST OF THE
PENINSULA BY THIS EVENING AS THEY GET KICKED OUT BY A DEEPENING
TROUGH INTO THE CENTRAL PLAINS STATES. THIS WILL ALSO BUILD A RIDGE
ACROSS THE AREA WITH A MUCH DRIER AND MORE STABLE ATMOSPHERE. SO A
MUCH QUIETER WEATHER PATTERN IS EXPECTED BY TUESDAY AND WEDNESDAY.
THAT BEING SAID, THE MENTION OF THUNDER ON TUESDAY HAS BEEN TAKEN
OUT OF THE GRIDS WITH FORECAST SOUNDINGS INDICATING PWAT DROPPING
TO LESS THAN AN INCH AND A QUARTER WITH VERY DRY ABOVE 5-10 K FEET.
LONG TERM (WEDNESDAY NIGHT THROUGH SUNDAY)...
LOOKING AHEAD TO THE END OF THE WEEK AND THE UPCOMING WEEKEND, MUCH
OF THE PERIOD WILL BE IN A BENIGN WEATHER PATTERN WITH MID LEVEL
RIDGING AND SURFACE HIGH PRESSURE STRETCHING ACROSS SOUTH FLORIDA.
ANOTHER WEAKENING COLD FRONT WILL MOVE INTO NORTH FLORIDA BY LATE
THURSDAY OR FRIDAY AND THEN RAPIDLY BECOMES DIFFUSE. SO LITTLE
CHANCE FOR RAINFALL AFTER TODAY THROUGH THE FORECAST PERIOD.
MARINE...
A NORTHEAST SWELL WILL BEGIN TO AFFECT THE ATLANTIC WATERS OFF OF
THE PALM BEACH COUNTY COAST THIS AFTERNOON AND CONTINUE THROUGH
LATE TONIGHT. THIS WILL RESULT IN ROUGH WATERS AND A SCA HAS BEEN
ISSUED FOR THIS REASON. OTHER THAN THAT, AN UPPER LEVEL
DISTURBANCE ALONG WITH A SURFACE TROUGH WILL MOVE ACROSS THE SOUTH
FLORIDA WATERS TODAY WITH NUMEROUS SHOWERS AND THUNDERSTORMS. SOME
OF THE STRONGER STORMS MAY PRODUCE STRONG WIND GUSTS. HIGH
PRESSURE WILL RETURN TO THE REGION TONIGHT AND CONTINUE THROUGH
THE END OF THE WEEK.
FIRE WEATHER...
THE RELATIVE HUMIDITY WILL REMAIN WELL ABOVE CRITICAL LEVELS
THROUGH MID WEEK AS HIGH PRESSURE BUILDS BACK ACROSS SOUTH FLORIDA
TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 84 67 83 69 / 70 30 10 -
FORT LAUDERDALE 83 72 84 74 / 60 40 10 -
MIAMI 85 71 86 73 / 70 40 10 -
NAPLES 85 67 88 67 / 50 20 10 -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 2 PM THIS AFTERNOON
TO 5 AM EDT TUESDAY FOR COASTAL WATERS FROM JUPITER INLET
TO DEERFIELD BEACH, FL OUT 20 NM-WATERS FROM JUPITER INLET
TO DEERFIELD BEACH, FL EXTENDING FROM 20 NM TO 60 NM.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...54/BNB
AVIATION/RADAR...13/SI
AREA FORECAST DISCUSSION
NWS MIAMI FL
741 AM EDT MON APR 22 2013
.AVIATION...
A LOW PRESSURE TROUGH WILL CROSS THE REGION TODAY...BRINGING
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. WIDESPREAD ACTIVITY
THIS MORNING IMPACTING ATLANTIC WATERS WILL MOSTLY STAY
OFFSHORE...AND LATEST GUIDANCE HINTS AT FAIRLY LOW COVERAGE OF
PRECIPITATION THROUGH THE MORNING HOURS. THUS...NO PREVAILING
SHRA/TSRA IN 12Z TAFS. INSTEAD...VCSH THROUGH 18Z...THEN VCTS. LOW
STRATUS IMPACTING BROWARD AND MIAMI-DADE TERMINALS...BUT THIS SHOULD
BREAK AWAY BY 13-14Z...THEN VFR PREVAILS. TEMPORARY BUT SIGNIFICANT
RESTRICTIONS ARE POSSIBLE THROUGHOUT THE DAY...IN AND NEAR PCPN.
HIGH PRESSURE BUILDS IN TONIGHT...WITH CLEARING SKIES EXPECTED.
GENERAL EASTERLY FLOW AT AROUND 10 KTS TODAY...BECOMING NORTH
TONIGHT. GUSTY WINDS ARE POSSIBLE NEAR THUNDERSTORMS.
&&
.PREV DISCUSSION... /ISSUED 328 AM EDT MON APR 22 2013/
SHORT TERM (TODAY THROUGH WEDNESDAY)...
THE GLOBAL MODELS ARE IN GENERAL AGREEMENT WITH THE OVERALL SYNOPTIC
SHORT TERM PATTERN IN DEPICTING A NEAR ZONAL FLOW ACROSS MUCH OF
SOUTHEASTERN STATES ALONG WITH A STATIONARY SURFACE FRONTAL TROUGH
ACROSS SOUTH CENTRAL FLORIDA. A FAST MOVING SOUTHERN STREAM MID
LEVEL TROUGH EMBEDDED WITHIN THIS FLOW IS CURRENTLY MOVING INTO THE
EASTERN GULF OF MEXICO AND WILL MOVE ACROSS THE PENINSULA THIS
MORNING. THIS FEATURE IS ALREADY GENERATING CONVECTION OVER THE
FLORIDA KEYS. THE SHORT TERM HIGH RESOLUTION MODELS HOWEVER DO NOT
HAVE A GOOD HANDLE ON WHAT EFFECTS THIS WILL HAVE FOR SOUTH FLORIDA
ESPECIALLY PARTICULARLY FOR TODAY. THE LOCALLY RUN WRF DID NOT
INITIALIZE WELL AT ALL AND IGNORES MUCH OF THE ONGOING CONVECTION.
THE HRRR DEPICTS THE AREA SHIFTING EAST DURING THE COURSE OF THIS
MORNING AND THIS SEEMS THE MOST REASONABLE GIVEN THE LATEST RADAR
AND SATELLITE ANIMATIONS. THE REAL DILEMMA IN TODAY`S FORECAST IS
JUST HOW MUCH DESTABILIZATION WILL OCCUR CONSIDERING THE EXTENSIVE
MID AND HIGH CLOUD COVER. GIVEN THE UNCERTAINTIES BUT THE FACT THAT
WE ARE BEING INFLUENCED BY A BROAD CYCLONIC FLOW ALOFT WITH 500 MB
TEMPERATURES OF AROUND -11C WILL SUPPORT MODEST INSTABILITY. IN
ADDITION, THE PWAT FROM THE 00Z MFL SOUNDING IS AT 1.87 INCHES WHICH
IS NEAR THE MAXIMUM FOR LATE APRIL WHICH SHOWS THE CHANCE FOR
LOCALLY HEAVY RAINFALL TO OCCUR. THEREFORE, ANY SUNSHINE THAT CAN
OCCUR TODAY WILL PROVIDE SUFFICIENT LIFT WITH SOME CHANCE FOR STRONG
WIND GUSTS AND SMALL HAIL ALONG WITH THE THREAT FOR LIGHTNING.
THE MID LEVEL AND SURFACE TROUGHS WILL SHIFT SOUTH AND EAST OF THE
PENINSULA BY THIS EVENING AS THEY GET KICKED OUT BY A DEEPENING
TROUGH INTO THE CENTRAL PLAINS STATES. THIS WILL ALSO BUILD A RIDGE
ACROSS THE AREA WITH A MUCH DRIER AND MORE STABLE ATMOSPHERE. SO A
MUCH QUIETER WEATHER PATTERN IS EXPECTED BY TUESDAY AND WEDNESDAY.
THAT BEING SAID, THE MENTION OF THUNDER ON TUESDAY HAS BEEN TAKEN
OUT OF THE GRIDS WITH FORECAST SOUNDINGS INDICATING PWAT DROPPING
TO LESS THAN AN INCH AND A QUARTER WITH VERY DRY ABOVE 5-10 K FEET.
LONG TERM (WEDNESDAY NIGHT THROUGH SUNDAY)...
LOOKING AHEAD TO THE END OF THE WEEK AND THE UPCOMING WEEKEND, MUCH
OF THE PERIOD WILL BE IN A BENIGN WEATHER PATTERN WITH MID LEVEL
RIDGING AND SURFACE HIGH PRESSURE STRETCHING ACROSS SOUTH FLORIDA.
ANOTHER WEAKENING COLD FRONT WILL MOVE INTO NORTH FLORIDA BY LATE
THURSDAY OR FRIDAY AND THEN RAPIDLY BECOMES DIFFUSE. SO LITTLE
CHANCE FOR RAINFALL AFTER TODAY THROUGH THE FORECAST PERIOD.
MARINE...
A NORTHEAST SWELL WILL BEGIN TO AFFECT THE ATLANTIC WATERS OFF OF
THE PALM BEACH COUNTY COAST THIS AFTERNOON AND CONTINUE THROUGH
LATE TONIGHT. THIS WILL RESULT IN ROUGH WATERS AND A SCA HAS BEEN
ISSUED FOR THIS REASON. OTHER THAN THAT, AN UPPER LEVEL
DISTURBANCE ALONG WITH A SURFACE TROUGH WILL MOVE ACROSS THE SOUTH
FLORIDA WATERS TODAY WITH NUMEROUS SHOWERS AND THUNDERSTORMS. SOME
OF THE STRONGER STORMS MAY PRODUCE STRONG WIND GUSTS. HIGH
PRESSURE WILL RETURN TO THE REGION TONIGHT AND CONTINUE THROUGH
THE END OF THE WEEK.
FIRE WEATHER...
THE RELATIVE HUMIDITY WILL REMAIN WELL ABOVE CRITICAL LEVELS
THROUGH MID WEEK AS HIGH PRESSURE BUILDS BACK ACROSS SOUTH FLORIDA
TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 81 67 83 69 / 80 30 10 -
FORT LAUDERDALE 81 72 84 74 / 70 30 10 -
MIAMI 83 71 86 73 / 70 30 10 -
NAPLES 82 67 88 67 / 70 20 10 -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 2 PM THIS AFTERNOON
TO 5 AM EDT TUESDAY FOR COASTAL WATERS FROM JUPITER INLET
TO DEERFIELD BEACH, FL OUT 20 NM-WATERS FROM JUPITER INLET
TO DEERFIELD BEACH, FL EXTENDING FROM 20 NM TO 60 NM.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...23/SK
AREA FORECAST DISCUSSION
NWS RALEIGH NC
950 AM EDT MON APR 22 2013
.SYNOPSIS...
AN AREA OF HIGH PRESSURE WILL EXTEND ACROSS THE PIEDMONT TODAY
THROUGH TUESDAY. MEANWHILE A LOW PRESSURE SYSTEM WILL DEVELOP OFF
THE SOUTHEAST COAST TODAY...THEN TRACK NORTHEAST JUST OFF THE EAST
COAST TONIGHT THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 950 AM MONDAY...
A COLD NORTHEASTERLY BREEZE CONTINUES THIS MORNING BETWEEN A STRONG
HIGH PRESSURE RIDGE OVER THE PIEDMONT AND AN AMPLIFYING COASTAL
TROUGH. STRATUS OVER THE COASTAL AREAS IS BEGINNING TO PUSH INLAND
AND 1000-2000 FT CEILINGS ARE SHOWING UP IN A FEW OBSERVATIONS EAST
OF I-95. THIS TREND WILL CONTINUE THROUGHOUT THE DAY AS ANOTHER
SHALLOW UPPER LEVEL DISTURBANCE CROSSES THE AREA THIS AFTERNOON AND
CAUSES WEAK CYCLOGENESIS EAST OF WILMINGTON THIS EVENING. 12Z RAOB
ANALYSIS SHOWS AN EASTERLY 850MB WIND AT KMHX AND KWAL...WHICH THE
LARGER SCALE MODELS WERE FORECASTING TO BE NORTH-NORTHEASTERLY AT
THIS TIME. STRONGER WARM ADVECTION AT 850MB MAY LEAD TO A MORE
AGGRESSIVE INLAND PUSH OF LOW CLOUDS...BUT MOISTURE IS VERY SHALLOW
AND THE RAP MODEL KEEPS MEASURABLE PRECIP MOSTLY EAST OF THE CWA.
THERMAL ADVECTION BELOW 850MB APPEARS TO NEARLY NEUTRAL...BUT
STRENGTHENING NORTHEASTERLY FLOW THIS AFTERNOON WILL STILL KEEP
HIGHS 10-15 DEGREES NORMAL. THUS...THE ONLY CHANGES THIS MORNING
WILL BE TO ADJUST SKY COVER TRENDS AND LOWER HIGHS A COUPLE DEGREES
OVER THE COASTAL PLAIN. HIGHS IN THE MID 50S EAST TO LOWER 60S
WEST. -SMITH
TONIGHT...LOW CLOUDS WILL LINGER AS THE SFC WAVE LIFTS NEWD JUST OFF
THE NC COAST. LOW LEVEL WINDS WILL BECOME MORE NLY VERSUS NELY BY
DAYBREAK. OVERCAST SKIES AND STEADY SFC WINDS WILL MAINTAIN TEMPS IN
THE LOW-MID 40S OVERNIGHT. IF CLOUD DECK THINS/DISSIPATE IN THE
WEST...COULD SEE A FEW SPOTS COOL INTO THE UPPER 30S.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 305 AM MONDAY...
TUESDAY...SFC WAVE OFF THE NC COAST EARLY TUESDAY MORNING WILL LIFT
QUICKLY NWD AS MID LEVEL TROUGH EXITS OFFSHORE. SUBSIDENCE BEHIND
THE DEPARTING SYSTEM AND ADVECTION OF DRIER AIR WILL AID TO
DISSIPATE THE LOW CLOUDS ACROSS THE REGION FROM WEST-TO-EAST.
INCREASING SUN WILL AID TO WARM TEMPS BACK INTO THE 60S TO NEAR 70
IN THE AFTERNOON WITH THE COOLER TEMPS IN THE FAR NORTHERN COASTAL
PLAIN WHICH WILL LIKELY HOLD ONTO SOME DECENT CLOUD COVERAGE UNTIL
MID AFTERNOON.
TUESDAY NIGHT...WEAK HIGH PRESSURE WILL EXTEND ACROSS THE REGION AT
THE SURFACE WHILE S/W RIDGE ALOFT SCOOTS EWD. BACKING W-SW FLOW
BEHIND THE DEPARTING MID LEVEL RIDGE WILL ADVECT MID-HIGH LEVEL
MOISTURE INTO CENTRAL NC. THIS WILL LEAD TO AN INCREASE IN HIGH
CLOUDS BY EARLY WEDNESDAY MORNING. RESIDUAL LOW LEVEL MOISTURE WILL
LIKELY CAUSE PATCHES OF FOG OR LOW CLOUDS TO DEVELOP. HOWEVER IF
HIGH CLOUDS ARRIVE SOONER OR THICKER THAN EXPECTED...THIS WILL DETER
DEVELOPMENT OF SIGNIFICANT FOG/LOW CLOUDS. MIN TEMPS TUESDAY NIGHT
3-6 DEGREES WARMER THAN TONIGHT WITH MIN TEMPS MID-UPPER 40S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 305 AM MONDAY...
WEDNESDAY THROUGH THURSDAY NIGHT:
THE NEXT SYSTEM WILL QUICKLY MOVE INTO THE AREA LATE WEDNESDAY INTO
WEDNESDAY NIGHT... LINGERING INTO THURSDAY. HOWEVER... WITH A
SOUTHERLY RETURN FLOW DEVELOPING ON WEDNESDAY MORNING... THERE WILL
BE LITTLE TIME FOR LOW LEVEL MOISTURE RECOVERY. GIVEN THE BEST
DYNAMICS WITH THE SYSTEM ARE EXPECTED TO PASS TO THE NORTH OF THE
REGION... WITH GENERALLY WEST TO WEST-SOUTHWESTERLY MID LEVEL
FLOW... OVERALL MOISTURE TRANSPORT DOES NOT LOOK OVERLY IMPRESSIVE
WITH THIS SYSTEM. THUS... CHANCES FOR ANY SVR STORMS LOOKS TO VERY
LOW. INSTEAD EXPECT A BAND OF SHOWERS AND MAYBE A FEW STORMS TO MOVE
INTO NORTHERN PORTIONS OF THE AREA ON WEDNESDAY... WITH A DECENT MID
LEVEL CAP GENERALLY HOLDING FOR THE DAYLIGHT HOURS ON WEDNESDAY.
EXPECT THE COLD FRONT SHOULD BEGIN SLOWLY SINKING
SOUTH-SOUTHEASTWARD THROUGH THE AREA OVERNIGHT WEDNESDAY/THURSDAY
MORNING... WITH THE FRONT EXPECTED TO BE LOCATED ACROSS OUR
SOUTHERN/SOUTHEASTERN COUNTIES BY 12Z THURSDAY BEFORE EVENTUALLY
PUSHING SOUTH OF THE AREA SOMETIME LATE THURSDAY MORNING/AFTERNOON.
A BULK OF THE SHOWERS MAY BE MORE ANAFRONTAL AND ASSOCIATED MORE
WITH THE 925-850 MB FRONT AND SECONDARY S/W TROUGH EXPECTED TO CROSS
THE AREA ON THURSDAY. FOR NOW WILL SHOW LIKELY POPS FROM AROUND
MIDNIGHT THURSDAY ACROSS THE NORTHWESTERN HALF OF THE AREA UNTIL
AROUND NOON FOR THE SOUTHEASTERN/EASTERN HALF OF THE CWA... WITH
SHOWERS POSSIBLY LINGERING INTO THE AFTERNOON ACROSS OUR EASTERN AND
SOUTHEASTERN COUNTIES. BEHIND THE EXITING S/W THURSDAY AFTERNOON
EXPECT DRIER AIR TO ADVECT INTO THE AREA AT THE SURFACE AND ALOFT.
WAA AHEAD OF THE FRONT SHOULD LEAD TO AFTERNOON LOW LEVEL THICKNESS
VALUES SOARING INTO THE 1380S... POSSIBLY 1390S ON WEDNESDAY
AFTERNOON. EVEN WITH THE INCREASING CLOUD COVER EXPECT HIGH TEMPS
SHOULD BE IN THE MID TO UPPER 70S... WITH A FEW LOCATIONS ACROSS THE
SOUTH AND EAST TOUGHING 80 DEGREES. GIVEN THE POSSIBLE ANAFRONTAL
PRECIP BY EARLY THURSDAY MORNING AND DURING THE DAY ON THURSDAY...
LOW AND HIGH TEMPS WILL BE VERY TRICKY AND DEPENDENT ON THE TIMING
OF THE FRONT...QPF... AND HOW MUCH OF A SURGE OF DRY AIR AT THE
SURFACE MAKES IT INTO THE AREA BEHIND THE FRONT WHILE PRECIP IS
STILL EXPECTED. WRT THE TIMING OF THE FRONT THE 00Z NAM AND GFS ARE
PRETTY CONSISTENT SHOWING THE FRONT ACROSS OUR FAR
SOUTHERN/SOUTHEASTERN COUNTIES BY 12Z THURSDAY... WITH THE 12Z ECMWF
A BIT FARTHER TO THE NORTH (BUT NOT MUCH... MAYBE A ROW OF COUNTIES
FURTHER NORTH). WILL USE A BEND OF THE 12Z ECMWF AND 00Z GFS.
THUS... WILL GO WITH LOW TEMPS BY THURSDAY MORNING RANDING FROM
AROUND 50 NORTH TO THE LOWER 60S FAR SOUTH. HIGH TEMPS WILL BE QUITE
TRICKY FOR THURSDAY AFTERNOON AND BE DRIVEN LARGELY BY THE QPF AND
IF WE SEE ANY CLEARING ACROSS THE WEST IN THE AFTERNOON. WILL GO ON
THE COOL SIDE OF THE GUIDANCE... ESPECIALLY ACROSS THE
EASTERN/NORTHEASTERN PORTION OF THE CWA WHERE SHOWERS AND CLOUD
COVER WILL LIKELY LINGER THE LONGEST. THIS YIELDS HIGH RANGING FROM
NEAR 60 NE TO AROUND 70 ACROSS THE FAR SOUTH (VERY LOW CONFIDENCE
TEMP FORECAST). WITH SURFACE HIGH PRESSURE BUILDING INTO THE AREA ON
THURSDAY NIGHT/FRIDAY MORNING EXPECT CLEARING SKIES... WITH MUCH
COOLER TEMPS EXPECTED BY FRIDAY MORNING. EXPECT LOW TEMPS FRIDAY
MORNING WILL BE GENERALLY IN THE 40S... WITH MAYBE EVEN A FEW OF THE
USUAL COLD SPOTS ACROSS THE NORTH PIEDMONT DROPPING TO AROUND 40
DEGREES.
FRIDAY THROUGH SUNDAY:
VERY BRIEF S/W RIDGING WILL BUILD ACROSS THE AREA FRIDAY/FRIDAY
EVENING... BEFORE THE NEXT DISTURBANCE APPROACHES THE AREA FROM THE
SW IN GENERAL BROAD CYCLONIC FLOW ACROSS THE CONUS. MEDIUM RANGE
MODELS ARE STRUGGLING WITH THE STRENGTH AND PROGRESSION OF THIS S/W
TROUGH. WILL FOLLOW CLOSE TO WPC FOR NOW AND HEDGE TOWARDS THE
SLOWER SIDE OF GUIDANCE. THIS SCENARIO GENERALLY KEEPS THE AREA DRY
FOR SATURDAY... WITH SHOWERS/RAIN EXPECTED SATURDAY NIGHT INTO
SUNDAY... WITH POSSIBLY SOME FORM OF DAMMING AIRMASS. TEMPS DURING
THIS PERIOD ARE EXPECTED TO RUN SLIGHTLY BELOW NORMAL TO POSSIBLY
WELL BELOW NORMAL IN THE HEART OF THE DAMMING REGION WITH PRECIP
SPREADING INTO THE AREA AND THE SURFACE RIDGE AXIS EXTENDING BACK
INTO OUR AREA FROM THE NORTHEAST ON SUNDAY.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 730 AM MONDAY...
VFR CONDITIONS AT 7 AM WILL GRADUALLY DETERIORATE FROM THE EAST
LATER THIS MORNING AS A STRENGTHENING LOW LEVEL NE FETCH OFF THE
ATLANTIC ADVECTS MOISTURE IN THE FORM OF A STRATUS INTO EASTERN AND
CENTRAL NC. THIS MVFR CEILING SHOULD REACH THE KRWI VICINITY BY
10-11 AM...AND THE KRDU AND KFAY TERMINAL SITES BY MID-DAY OR EARLY
AFTERNOON. THE MOISTURE APPEARS TO BE SHALLOW...SO NOT EXPECTING
MUCH IF ANY PRECIP ASIDE FROM SPOTS OF DRIZZLE OR LIGHT RAIN...MOST
LIKELY (BUT STILL LESS THAN A 30 PERCENT CHANCE) AT KRWI.
DUE TO THE DIFFERENCE IN PRESSURE BETWEEN A SURFACE RIDGE OVER THE
PIEDMONT AND A DEVELOPING LOW PRESSURE SYSTEM OFF THE SE U.S.
COAST...NE WINDS WILL STRENGTHEN THIS MORNING WITH SUSTAINED SPEEDS
CLOSE TO 15KTS AND GUSTS NEAR 25KTS...ESPECIALLY AT KFAY AND KRWI.
TONIGHT...THE STRATUS WILL REACH THE TRIAD TERMINALS SHORTLY BEFORE
SUNSET...RESULTING IN MVFR CEILINGS ACROSS A LARGE PORTION OF
CENTRAL NC OVERNIGHT. NE WINDS 10-15KTS WILL SLOWLY BACK TO A MORE
N-NE DIRECTION AS THE SURFACE LOW LIFTS NE ALONG THE NC COAST.
THE LOW WILL CONTINUE TO LIFT NE AWAY FROM NC TUESDAY MORNING. AS
THE LOW PULLS AWAY...SURFACE WINDS WILL BACK TO A MORE NW
DIRECTION...ADVECTING DRIER AIR INTO THE REGION. THIS WILL LEAD TO A
DISSIPATION OF THE STRATUS DECK AND IMPROVING AVIATION CONDITIONS.
VFR CONDITIONS SHOULD PREVAIL MOST TAF SITES BY MID DAY TUESDAY.
AN APPROACHING FRONTAL SYSTEM WILL BRING THE NEXT CHANCE FOR SUB-VFR
CONDITIONS WEDNESDAY NIGHT INTO THURSDAY. IMPROVING AVIATION
CONDITIONS ANTICIPATED THURSDAY NIGHT INTO FRIDAY AS HIGH PRESSURE
BUILDS INTO THE REGION FROM THE NORTHWEST.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS/SMITH
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
944 AM CDT MON APR 22 2013
.UPDATE...
ISSUED AT 945 AM CDT MON APR 22 2013
THE MAIN CHALLENGE WILL BE SNOW CHANCES IN THE FAR SOUTHERN
FORECAST AREA. THE 12Z NAM IS BRUSHING THE FAR SOUTH WITH PERHAPS
AN INCH OF SNOW...AND WILL INCREASE POPS HERE FROM 15-21Z IN THE
EXTREME SOUTHERN AREAS...WITH SOUTHERN GRANT COUNTY SEEING THE
BEST POTENTIAL FOR AN INCH OR PERHAPS 2. OTHERWISE...THE FORECAST
IS IN GOOD SHAPE WITH NO MAJOR CHANGES PLANNED.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 330 AM CDT MON APR 22 2013
FORECAST CHALLENGES CONCERN SNOW CHANCES ACROSS THE FAR SOUTH
TODAY AND TEMPERATURES. MODELS OVERALL IN GOOD AGREEMENT THROUGH
THE SHORT TERM AND WILL USE BLEND.
FOR TODAY FAR SOUTHERN FA WILL BE IN ENTRANCE REGION OF PASSING UPPER
JET MAXIMA. MAIN BAROCLINIC ZONE WELL SOUTH OF FA HOWEVER LOWER
CONDENSATION PRESSURE DEFICITS CLIP FAR SOUTHERN FA. MODELS HAVE
INITIALIZED PRETTY WELL WITH W SD SNOW BAND. NORTHERN EXTENT
SOMEWHAT IN QUESTION WITH RADAR COVERAGE HOWEVER HETTINGER AT THIS
POINT DRY SO SNOW SHOULD BE RIGHT ALONG OR JUST SOUTH OF BORDER.
BASED ON GOOD MODEL AGREEMENT FAR SOUTH WILL BE ON NORTHERN FRINGE
OF PCPN. WILL FOLLOW HIGH RESOLUTION RAP MODEL SOLUTION AND
INCREASE POPS ALONG ND/SD/MN BORDER AREA TODAY. STEADY COLD
ADVECTION AND SOME DEGREE OF CLOUD COVER WILL REALLY LIMIT ANY
TEMPERATURE RECOVERY. DVL BASIN MAY STRUGGLE TO GET TO
FREEZING/MELTING VALUES.
HIGH PRESSURE WILL BUILD INTO CENTRAL/NORTHERN PLAINS TONIGHT.
WITH LIGHT WINDS/MINIMAL CLOUD COVER AND COLD COLUMN WILL RESULT
IN COLD TEMPERATURES WITH RECORD LOWS POSSIBLE.
COLUMN WARMS SLIGHTLY TUESDAY AND ALONG WITH SOLAR AND MODEST
WESTERLY FLOW TEMPERATURES SHOULD BE A BIT WARMER.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM CDT MON APR 22 2013
MODEST TEMPERATURE RECOVERY WILL CONTINUE INTO MIDWEEK HOWEVER
WITH TEMPERATURES DROPPING BLO FREEZING AT NIGHT SNOW MELT PROCESS
WILL CONTINUE TO BE SLOW. NEXT WAVE TO SWING THROUGH BROAD CENTRAL
PLAINS MID LEVEL TROUGH WEDNESDAY HOWEVER LOOKS TO BE A LIGHT PCPN
EVENT.
THURSDAY TO SUNDAY...CONFIDENT IN A GENERALLY DRY PERIOD WITH
TEMPERATURES MODERATING TOWARD NEAR NORMAL BY NEXT WEEKEND. NW FLOW
ALOFT WITH SFC RIDGE AXIS IS EXPECTED TO DEPART THE REGION THURSDAY
WITH MORE ZONAL 500MB FLOW AND SOUTHERN RETURN FLOW ALLOWING FOR
850MB TEMPS TO WARM FROM 5 TO 10 BLO C THURS MORNING TO 5 TO 10
ABOVE BY FRI MORNING. WEAK SW AND FROPA WILL BRING SCHC OF SHRA FRI
AFTN. ANOTHER PERIOD OF WAA IS EXPECTED TO LIFT INTO THE REGION
SATURDAY AND SUNDAY WITH WEAK 500MB RIDGING WITH 850MB TEMPS PUSHING
INTO THE 10 TO 15 C RANGE.
HOW THESE TEMPS WILL INTERACT WITH SNOWPACK...ESPECIALLY IN THE
DEEPER SNOWS OF THE DEVILS LAKE BASIN AND NORTHERN RED RIVER
VALLEY...CAUSES SOME UNCERTAINTY IN THE OVERALL EXTENT OF THE WARM
UP. IF MIXING IS LESS THAN EXPECTED FOG WOULD BE LIKELY TO DEVELOP
OVERNIGHT LIMITING SOLAR INFLUENCES THE NEXT DAY OF THE WARM UP.
NONETHELESS LIKELY THAT THE GRADUAL SNOW MELT ENDS WITH OVERNIGHT
TEMPS ABOVE FREEZING BEGINNING FRIDAY NIGHT AND THRU THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 945 AM CDT MON APR 22 2013
SEEING EXTENSIVE MID AND HIGH LEVEL CLOUDS ALONG AND SOUTH OF A LINE
FROM KBIS TO KGFK TO KBDE. OF MAIN CONCERN TO THE AVIATION FORECAST
ARE SOME LOWER BATCHES OF CLOUDS...ONE AROUND THE KDVL AREA AND
ANOTHER UP AROUND THE LAKE OF THE WOODS. BOTH THESE BATCHES OF
CLOUDS ARE IN THE MVFR RANGE. THE AREA AROUND KDVL APPEARS TO BE
SINKING SLOWLY SOUTHWARD AND WILL AFFECT KDVL AND POSSIBLY KGFK.
&&
.HYDROLOGY...
ISSUED AT 330 AM CDT MON APR 22 2013
RIVER FLOOD WARNINGS IN EFFECT FOR SABIN ALONG THE S BR BUFFALO
RIVER...DILWORTH ALONG THE BUFFALO RIVER...AND WAHPETON ALONG THE
RED RIVER. DESPITE THE RELATIVELY COOL TEMPS...LOCALIZED RUNOFF
ALONG SOME OF THE MN TRIBS...INCLUDING ALONG THE BUFFALO... HAS
LEAD TO INCREASED RIVER STAGES. SIMILARLY...GRADUAL RISES HAVE
BEEN NOTED ALONG THE MAINSTEM RED AS WATER BEGINS TO MAKE ITS WAY
INTO THE SYSTEM. THIS IS ESPECIALLY TRUE ACROSS THE SOUTH TOWARDS
WAHPETON...WHERE MINOR FLOOD STAGE WILL LIKELY BE APPROACHED BY
EARLY THIS WEEK. COOLER TEMPS THROUGH THE MIDDLE OF THE WEEK WILL
LIMIT THE SNOWMELT PROCESS WITH WELL BELOW FREEZING TEMPS AT
NIGHT. IT APPEARS MORE SIGNIFICANT WARMING WILL OCCUR BY LATE THIS
WEEK. THIS WILL LEAD TO INCREASED SNOWMELT RUNOFF...AND MORE RAPID
RIVER RESPONSES BY NEXT WEEKEND. SOME UNCERTAINTY EXISTS REGARDING
THE DEGREE AND TIMING OF THE WARMER TEMPS...WHICH WILL AFFECT HOW
QUICKLY THE RIVERS RESPOND. NO SIGNIFICANT PRECIP EVENTS ARE
EXPECTED AT THIS TIME THROUGH THE COMING WEEK.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...DK
SHORT TERM...VOELKER
LONG TERM...JK
AVIATION...GODON
HYDROLOGY...JK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
650 AM CDT MON APR 22 2013
.UPDATE...
ISSUED AT 645 AM CDT MON APR 22 2013
ONLY CHANGES THIS UPDATE WERE TO DELAY SLIGHTLY SNOW CHANCES
ACROSS FAR SOUTHERN FA IN THE NEAR TERM. ANY -SN HAS YET TO REACH
THIS PORTION OF THE FA. REMAINDER OF FORECAST LOOKS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 330 AM CDT MON APR 22 2013
FORECAST CHALLENGES CONCERN SNOW CHANCES ACROSS THE FAR SOUTH
TODAY AND TEMPERATURES. MODELS OVERALL IN GOOD AGREEMENT THROUGH
THE SHORT TERM AND WILL USE BLEND.
FOR TODAY FAR SOUTHERN FA WILL BE IN ENTRANCE REGION OF PASSING UPPER
JET MAXIMA. MAIN BAROCLINIC ZONE WELL SOUTH OF FA HOWEVER LOWER
CONDENSATION PRESSURE DEFICITS CLIP FAR SOUTHERN FA. MODELS HAVE
INITIALIZED PRETTY WELL WITH W SD SNOW BAND. NORTHERN EXTENT
SOMEWHAT IN QUESTION WITH RADAR COVERAGE HOWEVER HETTINGER AT THIS
POINT DRY SO SNOW SHOULD BE RIGHT ALONG OR JUST SOUTH OF BORDER.
BASED ON GOOD MODEL AGREEMENT FAR SOUTH WILL BE ON NORTHERN FRINGE
OF PCPN. WILL FOLLOW HIGH RESOLUTION RAP MODEL SOLUTION AND
INCREASE POPS ALONG ND/SD/MN BORDER AREA TODAY. STEADY COLD
ADVECTION AND SOME DEGREE OF CLOUD COVER WILL REALLY LIMIT ANY
TEMPERATURE RECOVERY. DVL BASIN MAY STRUGGLE TO GET TO
FREEZING/MELTING VALUES.
HIGH PRESSURE WILL BUILD INTO CENTRAL/NORTHERN PLAINS TONIGHT.
WITH LIGHT WINDS/MINIMAL CLOUD COVER AND COLD COLUMN WILL RESULT
IN COLD TEMPERATURES WITH RECORD LOWS POSSIBLE.
COLUMN WARMS SLIGHTLY TUESDAY AND ALONG WITH SOLAR AND MODEST
WESTERLY FLOW TEMPERATURES SHOULD BE A BIT WARMER.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM CDT MON APR 22 2013
MODEST TEMPERATURE RECOVERY WILL CONTINUE INTO MIDWEEK HOWEVER
WITH TEMPERATURES DROPPING BLO FREEZING AT NIGHT SNOW MELT PROCESS
WILL CONTINUE TO BE SLOW. NEXT WAVE TO SWING THROUGH BROAD CENTRAL
PLAINS MID LEVEL TROUGH WEDNESDAY HOWEVER LOOKS TO BE A LIGHT PCPN
EVENT.
THURSDAY TO SUNDAY...CONFIDENT IN A GENERALLY DRY PERIOD WITH
TEMPERATURES MODERATING TOWARD NEAR NORMAL BY NEXT WEEKEND. NW FLOW
ALOFT WITH SFC RIDGE AXIS IS EXPECTED TO DEPART THE REGION THURSDAY
WITH MORE ZONAL 500MB FLOW AND SOUTHERN RETURN FLOW ALLOWING FOR
850MB TEMPS TO WARM FROM 5 TO 10 BLO C THURS MORNING TO 5 TO 10
ABOVE BY FRI MORNING. WEAK SW AND FROPA WILL BRING SCHC OF SHRA FRI
AFTN. ANOTHER PERIOD OF WAA IS EXPECTED TO LIFT INTO THE REGION
SATURDAY AND SUNDAY WITH WEAK 500MB RIDGING WITH 850MB TEMPS PUSHING
INTO THE 10 TO 15 C RANGE.
HOW THESE TEMPS WILL INTERACT WITH SNOWPACK...ESPECIALLY IN THE
DEEPER SNOWS OF THE DEVILS LAKE BASIN AND NORTHERN RED RIVER
VALLEY...CAUSES SOME UNCERTAINTY IN THE OVERALL EXTENT OF THE WARM
UP. IF MIXING IS LESS THAN EXPECTED FOG WOULD BE LIKELY TO DEVELOP
OVERNIGHT LIMITING SOLAR INFLUENCES THE NEXT DAY OF THE WARM UP.
NONETHELESS LIKELY THAT THE GRADUAL SNOW MELT ENDS WITH OVERNIGHT
TEMPS ABOVE FREEZING BEGINNING FRIDAY NIGHT AND THRU THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 645 AM CDT MON APR 22 2013
WILL SEE PRIMARILY VFR CONDITIONS ACROSS ALL TAF SITES TODAY.
COULD SEE A BRIEF MVFR PERIOD THIS MORNING ACROSS DVL BASIN WITH
MVFR CIGS JUST WEST OF THE FORECAST AREA. CONVECTIVE TEMPERATURES
ONLY AROUND 30 SO WILL LIKELY SEE SOME SC DEVELOPMENT HOWEVER CIGS
LOOK TO BE VFR.
&&
.HYDROLOGY...
ISSUED AT 330 AM CDT MON APR 22 2013
RIVER FLOOD WARNINGS IN EFFECT FOR SABIN ALONG THE S BR BUFFALO
RIVER...DILWORTH ALONG THE BUFFALO RIVER...AND WAHPETON ALONG THE
RED RIVER. DESPITE THE RELATIVELY COOL TEMPS...LOCALIZED RUNOFF
ALONG SOME OF THE MN TRIBS...INCLUDING ALONG THE BUFFALO... HAS
LEAD TO INCREASED RIVER STAGES. SIMILARLY...GRADUAL RISES HAVE
BEEN NOTED ALONG THE MAINSTEM RED AS WATER BEGINS TO MAKE ITS WAY
INTO THE SYSTEM. THIS IS ESPECIALLY TRUE ACROSS THE SOUTH TOWARDS
WAHPETON...WHERE MINOR FLOOD STAGE WILL LIKELY BE APPROACHED BY
EARLY THIS WEEK. COOLER TEMPS THROUGH THE MIDDLE OF THE WEEK WILL
LIMIT THE SNOWMELT PROCESS WITH WELL BELOW FREEZING TEMPS AT
NIGHT. IT APPEARS MORE SIGNIFICANT WARMING WILL OCCUR BY LATE THIS
WEEK. THIS WILL LEAD TO INCREASED SNOWMELT RUNOFF...AND MORE RAPID
RIVER RESPONSES BY NEXT WEEKEND. SOME UNCERTAINTY EXISTS REGARDING
THE DEGREE AND TIMING OF THE WARMER TEMPS...WHICH WILL AFFECT HOW
QUICKLY THE RIVERS RESPOND. NO SIGNIFICANT PRECIP EVENTS ARE
EXPECTED AT THIS TIME THROUGH THE COMING WEEK.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...VOELKER
LONG TERM...JK
AVIATION...VOELKER
HYDROLOGY...VOELKER
AREA FORECAST DISCUSSION
NWS TULSA OK
1048 AM CDT MON APR 22 2013
.DISCUSSION...
ELEVATED SHOWERS HAVE DEVELOPED ACROSS NORTH-CENTRAL OKLAHOMA AND
INTO OSAGE AND PAWNEE COUNTIES IN NORTHEAST OKLAHOMA. THIS ACTIVITY
WILL MOVE OFF TO THE NORTHEAST THROUGH THE REMAINDER OF THE MORNING
AND EARLY AFTERNOON. LOCAL MODELS AND THE LATEST HRRR KEEP SURFACE
BASED CONVECTION ALONG THE FRONT WHICH IS CURRENTLY ADVANCING INTO
NORTHERN KANSAS. THIS ACTIVITY LOOKS TO AFFECT NORTHEAST OKLAHOMA
AFTER 00Z.
TEMPERATURES LOOKS TO BE REASONABLE AND HAVE ONLY MADE SIGNIFICANT
ADJUSTMENTS TO THE SKY...POP AND WX GRIDS FOR TODAY.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...10
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
949 AM CDT MON APR 22 2013
.UPDATE...
WITH LESS CLOUDS THIS MORNING THAN PREVIOUSLY FORECASTED...HAVE
BUMPED UP HIGHS A COUPLE OF DEGREES ACROSS MOST OF THE AREA. DID
NOT GO QUITE AS HIGH AS WHAT THE RAP WAS FORECASTING /MID-80S/.
OTHERWISE...MADE MINOR CHANGES TO THE OTHER HOURLY GRIDS TO
ACCOUNT FOR CHANGES.
HAMPSHIRE
&&
.AVIATION...
/12Z TAFS/
CONCERNS...GUSTY WINDS TODAY AND MVFR CIGS TUESDAY MORNING.
STRATUS THIS MORNING HAS REMAINED WELL WEST OF THE TAF SITES.
SOUTH WINDS WILL INCREASE LATE THIS MORNING TO 15-18 KTS WITH
GUSTS AROUND 25 KTS. SPEEDS WILL DECREASE A LITTLE AROUND SUNSET
BUT CONTINUE TO BE BREEZY THROUGH THE END OF THE TAF PERIOD.
STRATUS WITH CIGS BETWEEN 1000-2000 FEET WILL SURGE NORTH OVER THE
REGION OVERNIGHT...REACHING WACO AROUND 08Z AND THE DFW
METROPLEX AROUND 09Z. LATE TUESDAY MORNING...A COLD FRONT WILL
ARRIVE IN THE METROPLEX WITH BREEZY NORTHWEST WINDS BEHIND THE
FRONT. THE FRONT WILL REACH WACO AROUND MIDDAY TOMORROW. THERE IS
A SMALL CHANCE FOR SHOWERS ALONG THE FRONT. MVFR CIGS WILL
CONTINUE BEHIND THE FRONT.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 353 AM CDT MON APR 22 2013/
TODAY WILL BE BREEZY AND WARMER WITH PLENTY OF SUNSHINE BUT
CHANGES ARE ON THE WAY TOMORROW AS AN UNSEASONABLY STRONG COLD
FRONT MOVES THROUGH. WE CONTINUE TO FAVOR THE SLIGHTLY FASTER
FRONTAL TIMING OF NAM/WRF MODELS...WHICH SUGGEST THE FRONT WILL
REACH THE DFW METROPLEX AROUND 9-10 AM TUESDAY...WACO AROUND
NOON...AND PUSH OUT OF THE SE ZONES BY 4 PM. HIGH TEMPS TUESDAY
WILL OCCUR AHEAD OF THE FRONT...AND WILL BE VERY SENSITIVE TO
EXACT FRONTAL TIMING. TEMPS BEHIND THE FRONT WILL PLUNGE 15-25
DEGREES...AND EXPECT THE NW HALF OF THE CWA TO BE IN THE UPPER 40S
BY MID-LATE AFTERNOON TUESDAY WITH A BRISK NORTHERLY WIND MAKING
IT FEEL EVEN COLDER. THE AIRMASS ACROSS NORTH TEXAS WILL BE CAPPED
BY A STRONG TEMPERATURE INVERSION NEAR 750MB...AND THEREFORE DEEP
CONVECTION ALONG THE FRONT APPEARS UNLIKELY. HOWEVER...THE FRONT
WILL PLOW INTO A SATURATED COLUMN BENEATH THIS INVERSION...AND
RAPID MECHANICAL LIFTING WILL LIKELY SQUEEZE OUT A THIN LINE OF
SHOWERS ALONG THE FRONTAL BOUNDARY. WOULD EXPECT MOST LOCATIONS TO
SEE BRIEF LIGHT RAIN TOMORROW...BUT THE CHANCE OF MEASURABLE
RAINFALL IS LOW AND THEREFORE WILL KEEP POPS AT 20 PERCENT.
OTHERWISE SOME AREAS OF DRIZZLE MAY DEVELOP OVER NORTH TEXAS
BEHIND THE FRONT IN THE AFTERNOON HOURS.
COLD AIR ADVECTION WILL CONTINUE INTO TUESDAY NIGHT AND EXPECT
TEMPS TO FALL INTO THE MID-UPPER 30S ACROSS THE NORTHERN ZONES TO
MID-UPPER 40S IN THE SOUTH FOR LOWS. SOUTHWEST FLOW ALOFT WILL
PREVAIL IN THE WAKE OF THE FRONT WHICH WILL SET UP AN OVERRUNNING
TYPE PATTERN. A SHORTWAVE TROUGH WILL MOVE THROUGH CENTRAL/EAST
TEXAS TUESDAY NIGHT. ELEVATED MOISTURE/INSTABILITY ARE SUFFICIENT
FOR WIDELY SCATTERED ELEVATED SHOWERS AND A FEW STORMS WITH BEST
CHANCES OVER THE SOUTHEAST HALF OF THE AREA WITH THIS WAVE TUESDAY
NIGHT. MODEL GUIDANCE IS STRUGGLING WITH TRYING TO TIME A SECOND
SUBSEQUENT SHORTWAVE. THE ECMWF IS POINTING AT WEDNESDAY NIGHT AND
THE GFS SEEMS TO HINT AT THIS AS WELL BUT SHOWS LITTLE QPF. THE
NAM/CANADIAN ARE EARLIER AND MORE FOCUSED ON WEDNESDAY. WILL BRUSH
SOME LOW POPS INTO WEDNESDAY BUT HOLD OFF ON BRINGING THEM INTO
WEDNESDAY NIGHT UNTIL WE GET MORE MODEL CONSISTENCY. THERE MAY BE
ENOUGH INSTABILITY FOR ELEVATED THUNDERSTORMS WITH THIS SECOND
SHORTWAVE BUT HAVE KEPT IT WORDED AS JUST SHOWERS FOR NOW. TEMPS
WEDNESDAY WILL BE IMPACTED SIGNIFICANTLY BY ANY POST-FRONTAL
CLOUDS/RAIN. WITH NORTH WINDS PREVAILING INTO WEDNESDAY AND CLOUDS
LIKELY TO PERSIST ACROSS AT LEAST THE SOUTHERN ZONES...HAVE
UNDERCUT GUIDANCE AND PUT HIGHS ONLY IN THE 50S THERE. THE
NORTHERN ZONES HAVE A BETTER CHANCE AT SEEING SOME LATE APRIL SUN
AND THEREFORE HAVE FORECAST WARMER TEMPS IN THE LOW 60S THERE.
COLD ADVECTION SHOULD WANE WEDNESDAY NIGHT AS WINDS TURN TO THE
EAST BUT CLOUDS SHOULD KEEP TEMPS FROM FALLING AS COOL AS GUIDANCE
SUGGESTS. BY THURSDAY...WINDS WILL TURN AROUND TO THE SOUTH BUT
STILL THINK THAT CLOUDS WILL BE PREVALENT AND TEMPER THE WARM UP.
HAVE UNDERCUT HIGHS FOR THURSDAY AND JUST WENT MID-UPPER 60S.
THE NEXT UPPER LEVEL SYSTEM IS A CLOSED LOW IN THE SUBTROPICAL
PACIFIC THAT WILL MELD WITH AN UPPER TROUGH OVER THE CONTINENT AND
MOVE ACROSS THE SOUTHERN PLAINS FRIDAY AND SATURDAY. STILL NOT
GETTING GREAT AGREEMENT IN THE MODELS WITH THIS FEATURE AND THE
ECMWF REMAINS THE STRONGEST/SLOWEST WITH IT. THE CANADIAN/UKMET
ARE PRETTY WEAK WITH THE FEATURE AND SUGGEST LIMITED QPF. THE GFS
SEEMS TO OFFER A COMPROMISE. WILL KEEP THE LOW POPS SPREAD ACROSS
THE AREA FRIDAY AND END THEM FROM WEST TO EAST SATURDAY. THE
AIRMASS ACROSS NORTH TEXAS WILL REMAIN FAIRLY COOL AND NOT HAVE
MUCH TIME TO RECHARGE OR DESTABILIZE AHEAD OF THIS SYSTEM...AND
THEREFORE WE MAY BE TOO STABLE OR CAPPED FOR A SIGNIFICANT
CONVECTIVE EVENT. THE CAP WOULD BE THE WEAKEST ACROSS THE
NORTHERN ZONES NEARER TO THE BETTER UPPER FORCING AND THEREFORE
HAVE BUMPED UP POPS TO 30 PERCENT IN THE NORTHEAST FRIDAY NIGHT.
OTHERWISE...THE ECMWF IS THE ONLY MODEL SHOWING A COLD FRONT
BEHIND THIS SYSTEM ON SATURDAY...AND THEREFORE HAVE KEPT WINDS
SOUTHERLY WITH TEMPS NEAR NORMAL SUNDAY INTO MONDAY.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 80 62 65 39 61 / 0 5 20 20 20
WACO, TX 81 62 72 42 58 / 0 5 20 30 20
PARIS, TX 77 58 65 40 62 / 0 10 20 20 10
DENTON, TX 80 59 59 37 62 / 0 10 20 20 10
MCKINNEY, TX 78 61 64 38 62 / 0 10 20 20 10
DALLAS, TX 80 63 66 42 61 / 0 5 20 20 20
TERRELL, TX 79 60 69 41 61 / 0 5 20 20 20
CORSICANA, TX 81 62 74 44 59 / 0 5 20 30 20
TEMPLE, TX 81 62 74 43 58 / 0 5 20 30 20
MINERAL WELLS, TX 81 55 55 36 60 / 0 5 20 20 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
85/85
AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
356 PM PDT MON APR 22 2013
SYNOPSIS... DRY AND UNSEASONABLY WARM WEATHER CONTINUES THROUGH
THIS WEEK AS HIGH PRESSURE RIDGING DOMINATES THE PATTERN. THERE
WILL BE BREEZY AND LOCALLY WINDY NORTH TO NORTHEAST WINDS
CONTINUING OVERNIGHT INTO TUESDAY. TEMPERATURES WILL GRADUALLY
COOL THROUGH THE THURSDAY AS RIDGING OVER THE AREA WEAKENS BUT
HIGHS WILL REMAIN ABOVE NORMAL.
.SHORT TERM DISCUSSION...
AT 3 PM SURFACE OBSERVATIONS SHOWED SACRAMENTO INTERNATIONAL
AIRPORT WAS 89 DEGREES...88 AT SACRAMENTO EXECUTIVE AIRPORT...88
IN FAIRFIELD AND 87 IN MARYSVILLE AND MODESTO. SACRAMENTO MAY SEE
THE FIRST 90 DEGREE DAY OF THE YEAR. REDDING AND RED BLUFF STARTED
THE DAY VERY MILD AT 64 DEGREES. IF TEMPERATURES DO NOT COOL BELOW
64 BY MIDNIGHT (WHICH IS UNLIKELY) THIS WILL BREAK THE RECORD HIGH
MINIMUM TEMPERATURE FOR THE DATE. THE TEMPERATURES THERE AT 3 PM
WERE ACTUALLY A COUPLE DEGREES COOLER THAN YESTERDAY AT THIS TIME.
AN UPPER LEVEL WAVE IS DIGGING INTO THE GREAT BASIN AND THIS
IS CREATING A RELATIVELY STRONG NORTH-SOUTH SURFACE PRESSURE GRADIENT.
SOME STRONGER WINDS ALOFT ARE MIXING DOWN AS GUSTS THIS
AFTERNOON. WINDS AT 3 PM WERE GUSTING UP TO 30 TO 37 MPH OVER
PORTIONS OF THE NORTHERN AND CENTRAL SACRAMENTO VALLEY. SOME
BLOWING DUST WAS REPORTED BY AN NWS EMPLOYEE ALONG INTERSTATE 5
NEAR CORNING. THE CURRENT GRADIENT IS AROUND 9.1 MB BETWEEN
MEDFORD AND SACRAMENTO WHICH IS A LITTLE WEAKER THAN THE 10 MB
THIS MORNING. THIS SHOULD WEAKEN FURTHER...THEN STRENGTHEN AGAIN
OVERNIGHT BUT WITH LIGHTER GUSTS. THE HRRR MODEL ALSO SHOWS SOME
WEAKENING IN WINDS FOR LATER AFTERNOON AND EVENING. THE STRONGEST
GRADIENT WILL BE OVERNIGHT WHEN MIXING SHOULD BE MORE LIMITED.
BREEZY WINDS ARE EXPECTED FOR TUESDAY. LOCALLY WINDY CONDITIONS
ARE FORECAST ALONG THE WEST SIDE OF THE VALLEY ON TUESDAY. WILL
HOLD OFF FOR NOW ON A WIND ADVISORY DUE TO THE LOCALIZED NATURE
OF THE STRONGER WINDS.
ANOTHER WAVE PASSES EAST OF THE AREA ON WEDNESDAY. THERE WILL BE
SOME FURTHER COOLING FOR THE FORECAST AREA AND IN INCREASE IN
CLOUDS OVER THE MOUNTAINS. HAVE LEFT A SLIGHT CHANCE OF RAIN
SHOWERS OVER THE SIERRA CREST SOUTH OF HIGHWAY 50 BUT EXPECT
LITTLE IN THE WAY OF PRECIPITATION THERE. WINDS WILL BE MORE
FOCUSED OVER SIERRA RIDGES AND CANYONS. THURSDAY SHOULD BE DRY
WITH LIGHT SOUTHWESTERLY WINDS AND SEASONABLY MILD TEMPERATURES. EK
&&
.EXTENDED DISCUSSION (FRIDAY THROUGH MONDAY)
WEAKENING 580DM RIDGE ALIGNED JUST OFFSHORE OF THE PACIFIC
COASTLINE THIS FRIDAY. HIGH PRESSURE RIDGE FLATTENS AND DROPS
SOUTHWARD SATURDAY AHEAD OF AN APPROACHING LOW AMPLITUDE TROUGH.
BOTH THE GFS AND EURO MODELS SHOW THE BASE OF THIS TROUGH ROUNDING
OUT THROUGH CENTRAL OREGON LATER IN THE WEEKEND WHICH WOULD KEEP
MOST OF THE ENERGY OUT OF CALIFORNIA. THE EUROPEAN MODEL SHOWS THE
UPPER LOW EJECTING A VORTICITY IMPULSE LATE SUNDAY TOWARDS OUR
AREA... HOWEVER WITH LIMITED SUPPORT THIS WILL ONLY RESULT IN
INCREASED CLOUDINESS OVER THE SOUTHERN CASCADES AND SIERRA NEVADA
EARLY NEXT WEEK. GFS RUN TO RUN CONSISTENCY RATHER LOW... WITH
FEATURES MOVING OUT OF PHASE. THE EUROPEAN MODEL SHOWS A MORE
CONSISTENT PICTURE FOR THE MIDDLE OF NEXT WEEK WITH WEAK HIGH
PRESSURE SET TO RETURN OVERHEAD. EXPECT DRY CONDITIONS WITH
SLIGHTLY ABOVE AVERAGE TEMPERATURES THROUGHOUT THE EXTENDED PERIOD.
&&
.AVIATION...
VFR CONDITIONS CONTINUE TONIGHT INTO TOMORROW FOR INTERIOR NORCAL
TAF SITES. A TROUGH BRUSHING TO THE NE WILL SETUP A NE-SW SURFACE
PRESSURE GRADIENT WHICH WILL BRING BREEZY WINDS TO THE AREA.
NORTHERLY WINDS OF 10-22 KTS AND GUSTS UP TO 34 KTS WILL CONTINUE
INTO THIS EVENING...WITH THE STRONGEST GUSTS IN THE NORTHERN SAC
VALLEY. INTERMITTENT GUSTY WINDS ARE POSSIBLE OVERNIGHT. SITES
THAT DECOUPLE TO WINDS LESS THAN 8 KNOTS OVERNIGHT WILL HAVE
STRONG WIND SHEAR AS NORTHEAST WINDS 20-30KTS CONTINUE SEVERAL
HUNDRED FEET ABOVE THE SURFACE. WINDS AT ALL SITES WILL RETURN BY
SUNRISE TOMORROW. -DVC
&&
.STO WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
259 PM CDT MON APR 22 2013
.DISCUSSION...
ISSUED 259 PM CDT MON APR 22 2013
MAIN WEATHER STORY CONTINUES TO BE THE RAIN EVENT COMING INTO THE
PICTURE LATE TONIGHT THROUGH TUESDAY NIGHT.
19Z/2PM SURFACE MAP SHOWS HIGH PRESSURE EXTENDING FROM NEW ENGLAND
TO THE WESTERN GULF OF MEXICO. FURTHER NORTHWEST...LOW PRESSURE IS
CENTERED NEAR HUDSON BAY...WITH STRONG COLD FRONT TRAILING
SOUTHWESTWARD INTO THE CENTRAL PLAINS. ALOFT...LARGE RIDGE IS IN
PLACE OVER THE EASTERN PACIFIC...WHILE A VIGOROUS SHORT-WAVE
DROPPING INTO THE CENTRAL ROCKIES IS BEGINNING TO DIG A TROUGH
DOWNSTREAM ACROSS THE CENTRAL CONUS.
SHORT TERM...TONIGHT THROUGH THURSDAY
LEAD SHORT-WAVE CURRENTLY EVIDENT ON WATER VAPOR IMAGERY OVER
WESTERN NEBRASKA/KANSAS WILL TRACK EASTWARD THIS EVENING. CLUSTER
OF THUNDERSTORMS ASSOCIATED WITH THIS FEATURE WEST OF KANSAS CITY
WILL SHIFT EASTWARD AND WEAKEN WITH TIME AS IT ENCOUNTERS A MUCH
DRIER AIRMASS FURTHER EAST ACROSS ILLINOIS. 3KM HRRR SHOWS REMNANTS
OF THIS CONVECTION TRYING TO WORK ITS WAY INTO WEST-CENTRAL
ILLINOIS BETWEEN 00Z AND 03Z...HOWEVER QPF AMOUNTS ARE PALTRY.
BASED ON INITIALLY VERY DRY FORECAST SOUNDINGS...THINK THIS FIRST
WAVE WILL DO LITTLE MORE THAN TO MOISTEN THE AIRMASS FOR THE MAIN
WAVE ON TUESDAY. HAVE THEREFORE DOWNPLAYED RAIN CHANCES EARLY
TONIGHT...FEATURING ONLY LOW CHANCE POPS FOR SHOWERS WEST OF I-55
THROUGH MIDNIGHT. RAIN CHANCES BEGIN TO INCREASE OVERNIGHT...AS
MAIN WAVE AND ASSOCIATED COLD FRONT APPROACHES FROM THE WEST.
SOUNDINGS SHOW AT LEAST MODEST ELEVATED INSTABILITY...SO WILL
MENTION CHANCE FOR THUNDER AFTER MIDNIGHT.
FRONTAL BOUNDARY SLOWLY PUSHES EASTWARD THROUGH CENTRAL ILLINOIS
ON TUESDAY...WITH SURFACE LOW PRESSURE EXPECTED TO RIDE ALONG THE
BOUNDARY AS IT DOES SO. COMBINATION OF STRONG LOW-LEVEL FORCING
ALONG FRONT...VIGOROUS UPPER DYNAMICS COMING IN FROM THE WEST...AND
INCREASINGLY DEEP MOISTURE WITH PRECIPITABLE WATER VALUES
EXCEEDING 1 INCH...WILL LEAD TO THE DEVELOPMENT OF WIDESPREAD
SHOWERS AND THUNDERSTORMS ACROSS THE AREA. AM NOT ANTICIPATING
SEVERE WEATHER...HOWEVER A FEW STRONG THUNDERSTORMS WILL BE
POSSIBLE EAST OF I-55 DURING THE AFTERNOON. BEST INSTABILITY AND
SHEAR PARAMETERS WILL REMAIN FOCUSED A BIT FURTHER SOUTHWEST
ACROSS THE OZARKS AND LOWER OHIO RIVER VALLEY.
ONCE SURFACE LOW LIFTS INTO THE GREAT LAKES...FRONT WILL GET
PULLED EASTWARD INTO INDIANA BY EARLY EVENING. ALL OPERATIONAL
MODELS SUGGEST PLENTY OF SHOWERS LINGERING BEHIND THE BOUNDARY AT
LEAST THROUGH MIDNIGHT. HAVE THEREFORE MAINTAINED HIGH POPS
THROUGH THE EVENING...WITH STEADILY DECREASING CHANCES AFTER
MIDNIGHT. MAY EVEN BE ENOUGH COLD AIR ADVECTING INTO THE AREA
BEHIND THE FRONT TO CHANGE THE RAIN SHOWERS TO A BRIEF PERIOD OF
SNOW SHOWERS ACROSS THE ILLINOIS RIVER VALLEY OVERNIGHT...HOWEVER
THINK MOST OF THE MOISTURE WILL DEPART BEFORE IT GETS COLD ENOUGH
FOR THAT TO HAPPEN. WILL HOWEVER MENTION JUST A SLIGHT CHANCE FOR
SNOW SHOWERS ACROSS THE FAR WESTERN KILX CWA IN CASE MOISTURE
LINGERS. TOTAL RAINFALL FROM THIS SYSTEM WILL GENERALLY BE BETWEEN
THREE QUARTERS AND ONE INCH...HOWEVER AMOUNTS IN EXCESS OF ONE
INCH WILL BE LIKELY EAST OF I-55 WHERE A FEW STRONGER STORMS MAY OCCUR.
MUCH COOLER/DRIER AIRMASS WILL ARRIVE ON WEDNESDAY AND
THURSDAY...WITH HIGHS DROPPING BACK INTO THE 50S AND OVERNIGHT
LOWS DIPPING INTO THE 30S. MODELS STILL SHOW A NORTHERN-STREAM
SHORT-WAVE TRACKING ACROSS THE UPPER MIDWEST AND GREAT LAKES
WEDNESDAY NIGHT...HOWEVER THINK MOISTURE WILL BE LACKING AND
STRONGEST LIFT WILL REMAIN WELL TO THE NORTH. HAVE THEREFORE ONLY
MENTIONED A CHANCE FOR SPRINKLES/FLURRIES FROM THE PEORIA AREA
NORTHWARD.
LONG TERM...FRIDAY THROUGH MONDAY
MODELS CONTINUE TO STRUGGLE WITH THE POTENTIAL SYSTEM AT THE END
OF THE WEEK. SYSTEM IN QUESTION IS A CUT-OFF LOW OFF THE COAST OF
SOUTHERN CALIFORNIA THAT WILL EVENTUALLY GET ABSORBED INTO THE
PREVAILING W/NW FLOW ACROSS THE CONUS AND GET EJECTED EASTWARD BY
FRIDAY/SATURDAY. GFS HAS CONSISTENTLY BEEN FASTER AND FURTHER
NORTH WITH ITS TRACK...SPREADING RAIN INTO CENTRAL ILLINOIS
FRIDAY/FRIDAY NIGHT. MEANWHILE...ECMWF HAS BEEN CONSISTENTLY
SLOWER AND FURTHER SOUTH...KEEPING MUCH OF THE RAIN ACROSS THE
TENNESSEE AND OHIO RIVER VALLEYS ON SATURDAY/SUNDAY. GEM SUPPORTS
THE SLOWER ECMWF...SO WILL TREND TOWARD THIS SOLUTION FOR THE
EXTENDED. AS A RESULT...HAVE OPTED TO KEEP FRIDAY DRY...WITH LOW
CHANCE POPS ARRIVING FRIDAY NIGHT. AFTER THAT...HAVE CONFINED RAIN
CHANCES TO MAINLY THE SOUTHERN CWA ON SATURDAY...WITH MAIN FOCUS
FOR MORE SIGNIFICANT RAINFALL REMAINING SOUTH OF THE AREA.
BARNES
&&
.AVIATION...
ISSUED 1230 PM CDT MON APR 22 2013
VFR CONDITIONS EXPECTED THROUGH AT LEAST 06Z OVER CENTRAL
ILLINOIS...WITH JUST SOME LOWERING MID AND HIGH CLOUDS. HOWEVER...
CU-RULE AND SOUNDINGS SHOWING SOME SCATTERED CLOUDS AS LOW AS
4000 FEET THIS AFTERNOON FROM KSPI-KCMI. INCOMING COLD FRONT FROM
THE WEST HAS BEEN SLOWING DOWN...SO HAVE BACKED OFF ON THE VCSH
MENTION FOR A FEW HOURS UNTIL AROUND 05Z OR LATER...AND MAY BE
CLOSER TO 12Z TOWARD KDEC/KCMI. ONCE THE FRONT PASSES...SHOWERS
WILL BECOME MORE STEADY AND CEILINGS SHOULD FALL TO AROUND 2000
FEET. CURRENTLY DOES NOT APPEAR TO BE A MAJOR THREAT OF THUNDER...
BUT NAM MODEL INDICATES A LOW POTENTIAL AROUND KCMI TOWARD THE END
OF THE TAF PERIOD...SO WILL NEED TO KEEP AN EYE ON THIS.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
118 PM CDT MON APR 22 2013
.UPDATE...
ISSUED AT 1215 PM CDT MON APR 22 2013
NO MAJOR CHANGES WITH THE ASSORTMENT OF SHORT-RANGE GUIDANCE
COMING IN THIS MORNING. WE ARE SEEING THE HIGHER END POTENTIAL
THROUGH THE ASSORTMENT OF HIGH RESOLUTION WRF SOLUTIONS WE HAVE
ACCESS TO...IN ADDITION TO THE RAP AND HRRR RUNS BETWEEN 14-16Z. THE
HOPWRF /WHICH CAN BE FOUND AT HOPWRF.INFO/ IS NOW OUT THROUGH 06Z
AND THE ENSEMBLE MEAN GIVES MUCH OF SOUTHERN MN AND FAR WEST
CENTRAL WI 0.75"-1.00" LIQUID AND EVEN GIVES SOME AREAS IN SOUTH
CENTRAL MN OVER 1.00". SOUTH CENTRAL MN WAS ALSO AN AREA
HIGHLIGHTED BY THE 22.09Z SREF WITH AT LEAST SOME PERCENT CHANCE
OF >12" SNOW IN 12 HOURS. THE SHORT-TERM GUIDANCE CONTINUES TO
PAINT A 1-2 COUNTY- WIDE SWATH OF 8-12 INCHES SNOWFALL JUST ON THE
NORTH SIDE OF THE RAIN/SNOW LINE. MODEL CONSENSUS PUTS THE
MESOSCALE HEAVY SNOW BAND ALONG A LINE FROM MANKATO...THROUGH THE
TWIN CITIES METRO...AND UP THROUGH RICE LAKE WI. THE 12Z SOUNDING
HERE AT MPX THIS MORNING HAD AT LEAST THE WEST METRO COLD ENOUGH
FOR SNOW RIGHT AT THE ONSET OF PRECIP AND THAT`S WHAT WE ARE
SEEING IN SOUTHWEST MN. FORECAST SOUNDINGS ONLY COOL WITH TIME
TODAY...SO ABOVE THE SURFACE WE ARE GOOD TO GO FOR HEAVY SNOW
ALONG THE LINE MENTIONED ABOVE. THE CAVEAT IS THE NEAR SURFACE
LAYER DUE TO DAYTIME HEATING. WE ARE NOW NEAR 40 OR IN THE LOWER
40S...SO THE SNOWFLAKES MAY TURN TO RAINDROPS 500-1000 FT ABOVE
THE GROUND. SO...WE COULD STILL SEE A 2-3 HOUR WINDOW OF RAIN/SNOW
BEFORE THE CHANGE OVER HAPPENS...AND WE QUICKLY FIND OURSELVES WITH
1-2" PER HOUR RATES. THE SNOW GRADIENT WILL BE EXTREMELY TIGHT.
PERHAPS A 7-8" INCH SNOW GRADIENT OVER THE SPAN OF A SINGLE
COUNTY. WE WILL UNDOUBTEDLY MISS IN SOME AREA WITH THIS KIND OF
GRADIENT. THE TIGHTEST GRADIENT SHOULD BE ALONG THE RAIN/SNOW
LINE...BUT TOTALS SHOULD ALSO QUICKLY FALL TO THE NORTHWEST. SO
EVEN PORTIONS OF THE WESTERN TWIN CITIES METRO AND CERTAINLY ST.
CLOUD WILL SEE LESSER TOTALS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 414 AM CDT MON APR 22 2013
MOTHER NATURE IS AT IT AGAIN! MAJOR CHANGES HAVE BEEN MADE TO THE
SHORT TERM WITH REGARDS TO THE SYSTEM WE HAVE BEEN FOLLOWING FOR THE
PAST FEW DAYS. THE 00Z MODEL RUNS...INCLUDING THE GLOBAL ENSEMBLES
AND MESOSCALE MODELS...HAVE REALLY COME INTO LINE IN SHOWING A
QUICK-HITTING MAJOR WINTER STORM TAKING SHAPE LATER THIS AFTERNOON
AND INTO TONIGHT. IN FACT...THE NAM...GFS...CANADIAN... SREF...AND
GEFS MODELS ARE ALL IN VERY GOOD AGREEMENT LEADING TO A RELATIVELY
HIGH CONFIDENCE FORECAST.
LOW PRESSURE WILL TRACK NORTHEAST FROM THE SOUTHERN PLAINS TO
SOUTHWESTERN WISCONSIN BY MIDNIGHT TONIGHT...THEN TO NORTHEAST
WISCONSIN BY EARLY TUESDAY MORNING. A COLD FRONT WILL SINK SOUTH
ACROSS THE AREA AND STALL ACROSS SCTRL MN/WCTRL WI THIS EVENING.
PRECIPITATION WILL SPREAD OVERHEAD FROM THE SOUTHWEST LATER THIS
MORNING OR INTO THE AFTERNOON. IT WILL BEGIN INITIALLY AS SNOW
ACROSS WRN MN...BUT WARMER AIR ALOFT FURTHER EAST WILL KEEP IT RAIN
UNTIL CAA TO THE NORTH AND WEST OF THE SURFACE LOW TURNS IT TO ALL
SNOW. THIS TRANSITION WILL TAKE PLACE AT NEW ULM AROUND 3 PM...TWIN
CITIES AROUND 5 PM...AND NEW RICHMOND/RICE LAKE AROUND 7 PM.
THINK THE ARRIVAL OF THE COLD AIR WILL BE QUICK ENOUGH ALONG
A LINE FROM A NEW ULM...TWIN CITIES...MORA LINE TO KEEP THE MAJORITY
OF SIGNIFICANT PRECIP AS SNOW WITH THIS SYSTEM. LOCATIONS NEAR THE
STALLED FRONT WILL STILL HAVE MARGINAL THERMAL PROFILES...FAVORING
MORE OF A RAIN/SNOW MIX FOR THE MAJORITY OF THE EVENT. THIS WOULD
INCLUDE EAU CLAIRE AND ALBERT LEA.
VERY IMPRESSIVE FRONTOGENESIS WITHIN THE DENDRITIC GROWTH ZONE TAKES
SHAPE EARLY THIS EVENING WITHIN 40 MILES OF THE AFOREMENTIONED LINE.
THUS...THERE SHOULD BE INTENSE BANDING WITHIN THE LARGER DEFORMATION
AREA WITH SNOW RATES OF 1 TO 2+ INCHES PER HOUR SETTING UP. LATE
SEASON SYSTEMS ARE NOTORIOUS FOR PRODUCING THUNDERSNOW...ESPECIALLY
WITH THIS LEVEL OF FRONTOGENESIS SO ALSO MENTIONED ISOLATED
THUNDERSTORMS TONIGHT.
QPF IS VERY SIMILAR ON THE MODELS MENTIONED...AND WENT WITH A
GFS/NAM/SREF COMBO FOR LIQUID. USING ROUGHLY A 10:1 RATIO TONIGHT
YIELDS A GOOD 6 TO 9 INCHES OF SNOW FROM SWRN MN TO ECTRL MN AND
NWRN WI. THE HIGHEST AMOUNTS ARE EXPECTED IN AND NORTHEAST OF THE
TWIN CITIES METRO WHERE THE DEFORMATION BAND WILL REACH ITS MATURE
PHASE. ISSUED A WINTER STORM WARNING FOR THE MOST OF SRN MN AND WRN
WI...WITH A WINTER WEATHER ADVISORY FOR A ROW OF COUNTIES
SURROUNDING THE WARNING WHERE 3 TO 6 INCHES ARE FORECAST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 347 AM CDT MON APR 22 2013
FORECAST BEGINS WITH THE VESTIGES OF THE LAST HEAVY SNOW
EVENT FOR THE WINTER/SPRING SEASON ENDING ON TUESDAY MORNING
OVER WEST CENTRAL WI. COULD BE ANOTHER QUICK FEW TENTHS TO
NEAR ONE HALF INCH OVER THIS REGION FROM 12Z TO 18Z. EXPECT
SOME SLIGHT BLOWING AND DRIFTING OF HEAVY SNOW OVER EAST CENTRAL
MN AND WEST CENTRAL WI DURING THIS TIME FRAME AS WELL...ASSOCIATED
WITH SUSTAINED NORTHERLY WINDS IN THE 10 TO 20 MPH RANGE. NEW
COATING OF 2 TO 8 INCHES OF SNOW WILL PUT A CAP ON MAX READINGS
FOR TUESDAY. CLOUD COVER SHOULD DECREASE MARKEDLY ON TUESDAY NIGHT.
ONLY ELEMENT KEEPING US FROM PLUNGING BACK INTO THE UPPER SINGLE
DIGITS TO MID TEENS TOMORROW NIGHT IS FAIRLY ROBUST PRESSURE
GRADIENT. THAT SAID...TEMPERATURES WILL STILL BE 10 TO NEAR 15
DEGREES BELOW NORMAL FOR MUCH OF THE CWA.
WEAK SURFACE TROUGH AND MODERATE 50H TROUGH JUST TO ITS LEE WILL
BE THE IMPETUS FOR ANOTHER ROUND OF PCPN WED MORNING INTO THE
EVENING HOURS. USED GFS40 285K ISENTROPIC ANAL FOR PLACEMENT
OF PCPN TRENDS. 850 TEMPS AT THIS JUNCTURE PRETTY MUCH GUARANTEEING
MOST OF EVENT WILL BE OF LIQUID VARIETY. ALTHOUGH MOISTURE WILL
BE LACKING WHEN SUB ZERO TEMPS ALOFT ARE PRESENT WED EVENING
...COULD BE ENOUGH MOISTURE AND FORCING STILL PREVALENT TO PRODUCE
A QUICK FEW TENTHS TO JUST OVER ONE HALF INCH OF SNOW ACROSS
MAINLY WEST CENTRAL WI AND PORTION OF EAST CENTRAL MN.
ZONAL FLOW TAKES OVER AGAIN OVER MUCH OF LOWER 48 BY THURSDAY AFTN.
MID LEVEL TROUGH COULD BRING SLT POPS TO MUCH OF FA FRI AFTN/EVE.
ANOTHER SURFACE TROUGH IMPETUS FOR CHANCE POPS ACROSS MUCH OF FA
SATURDAY NIGHT INTO EARLY MONDAY MORNING. FORCING WITH BOTH SYSTEMS
APPEARS TO BE MINIMAL...WITH QPF READINGS MAINLY IN THE TWO TENTHS
OF AN INCH RANGE OR LESS RANGE ANTICIPATED WITH BOTH SYSTEMS. SOUTH
CENTRAL MN COULD ENCOUNTER A FEW TENTHS OF AN INCH MORE LATE SAT
NIGHT...ASSOCIATED WITH ISOLATED THUNDERSTORM ACTIVITY AS INSTABILITY
INCREASES NOTICEABLY.
TEMPERATURES WILL FINALLY BREACH THE 60 DEGREE MARK ACROSS MUCH OF
THE FA ON FRIDAY...AS WAA INCREASES WITH STRONG SOUTHWESTERLY FLOW
THROUGHOUT THE DAY. TEMPERATURES WILL SLOWLY INCREASE RIGHT INTO THE
WEEKEND...AND RIGHT INTO THE LAST WEEK OF APRIL. FAR AND AWAY THE MOST
NEWSWORTHY ITEM OF THE EXTENDED INVOLVES THE LONG AWAITED APPEARANCE
OF A SIGNIFICANT 50H RIDGE OVER THE UPPER MIDWEST...WHICH WILL
COMMENCE OVER THE DAKOTAS NEXT TUESDAY...AND ENCOMPASS MN AND WI
BY NEXT WEDNESDAY. TEMPERATURES SHOULD EASILY LIFT INTO THE 70S
OVER OUR FA DURING THIS PERIOD...WITH EVEN A CHANCE FOR A FEW
80 DEGREE READINGS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1242 PM CDT MON APR 22 2013
BIG CHANGES TO OUR WEATHER AT THE TERMINALS IS RIGHT ON THE DOOR
STEP. THE SHORT TERM MODELS ARE IN GOOD AGREEMENT SO NO
SIGNIFICANT CHANGES TO THIS SET OF TERMINAL FORECASTS. LOW
PRESSURE OVER WESTERN KANSAS WILL MOVE NORTHEAST TOWARD SOUTHEAST
MINNESOTA THIS EVENING AND THEN INTO THE UPPER PENINSULA OF
MICHIGAN BY MORNING. TREMENDOUS VERTICAL MOTION AND OTHER
ATMOSPHERIC DYNAMICS IN PLACE TO CREATE VERY IMPRESSIVE SNOW
RATES AT KMSP/KRNH. IN FACT THERE IS A SLIGHT CHANCE OF THUNDER
FROM CENTRAL IOWA TO NEAR DLH. WILL NOT CARRY THUNDER IN THE TAFS
AS IT WILL BE EXTREMELY ISOLATED. WITH THE GREAT SNOW RATES WILL
COME REDUCED VISIBILITIES. TEMPERATURES ARE COLD ENOUGH WEST AND
NORTH OF KMSP FOR THE PRECIPITATION TO BEGIN AS SNOW AND REMAIN
ALL SNOW. AS THE LOW MOVES NORTHEAST INTO WISCONSIN THIS EVENING
COLDER AIR WILL FILTER INTO THE EASTERN TERMINALS WITH KEAU
SWITCHING TO ALL SNOW BY 10Z TUESDAY. AIRCRAFT SOUNDINGS INDICATE
THERE IS A 1400 FOOT LAYER OF WARM AIR AT KMSP...THEREFORE EXPECT
KMSP TO HAVE A RASN MIXTURE UNTIL 23-00Z AND THEN ALL SNOW. EAU
SHOULD KEEP A RA/SN MIX GOING THROUGH THE EVENING. A PERIOD OF
HEAVY SNOW EXPECTED FROM EAST OF RWF TO MSP AND RNH THIS EVENING
WITH 1-2 IN/HR SNOW RATES POSSIBLE. THE SNOW WILL TAPER OFF OVER
MIDNIGHT EXCEPT FOR KEAU.
KMSP...VFR CONDITIONS CURRENTLY...WHICH WILL DETERIORATE QUICKLY
AFTER 21Z. RAIN WILL ARRIVE AROUND 1930Z AND A RAIN SNOW MIX WILL
BE NOTED AROUND THE 21Z TIME FRAME. ALL SNOW AROUND 00Z. A PERIOD
OF HEAVY SNOW IS LIKELY THIS EVENING WITH LIFR CONDITIONS...THEN
CONDITIONS WILL IMPROVE AFTER 07Z WITH FLURRIES AFTER 10Z FOR A
FEW HOURS. WINDS WILL BE GUSTY FROM THE NORTH.
/OUTLOOK FOR KMSP/
WED...VFR. CHC MVFR/-RASN AFTN. SW WINDS 10-15 KTS.
THU...VFR. SW WINDS 8-15 KTS.
FRI...VFR. SW WINDS 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 7 AM CDT
TUESDAY FOR MNZ044-045-050>052-058>061-066-068-069-076.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 7 AM CDT
TUESDAY FOR MNZ043-049.
WINTER WEATHER ADVISORY UNTIL 1 AM CDT TUESDAY FOR MNZ048-
054>057-064.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 AM CDT TUESDAY
FOR MNZ053-062-063-070-077.
WINTER STORM WARNING UNTIL 1 AM CDT TUESDAY FOR MNZ065-067-
073>075-082-083-091.
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM CDT
TUESDAY FOR MNZ078-084-085-092.
WI...WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 AM CDT TUESDAY
FOR WIZ014>016-023.
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM CDT
TUESDAY FOR WIZ024-025-027.
&&
$$
UPDATE...CLF
SHORT TERM...BORGHOFF
LONG TERM...AJZ
AVIATION...DRL
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1238 PM CDT MON APR 22 2013
.UPDATE...
ISSUED AT 1215 PM CDT MON APR 22 2013
NO MAJOR CHANGES WITH THE ASSORTMENT OF SHORT-RANGE GUIDANCE
COMING IN THIS MORNING. WE ARE SEEING THE HIGHER END POTENTIAL
THROUGH THE ASSORTMENT OF HIGH RESOLUTION WRF SOLUTIONS WE HAVE
ACCESS TO...IN ADDITION TO THE RAP AND HRRR RUNS BETWEEN 14-16Z. THE
HOPWRF /WHICH CAN BE FOUND AT HOPWRF.INFO/ IS NOW OUT THROUGH 06Z
AND THE ENSEMBLE MEAN GIVES MUCH OF SOUTHERN MN AND FAR WEST
CENTRAL WI 0.75"-1.00" LIQUID AND EVEN GIVES SOME AREAS IN SOUTH
CENTRAL MN OVER 1.00". SOUTH CENTRAL MN WAS ALSO AN AREA
HIGHLIGHTED BY THE 22.09Z SREF WITH AT LEAST SOME PERCENT CHANCE
OF >12" SNOW IN 12 HOURS. THE SHORT-TERM GUIDANCE CONTINUES TO
PAINT A 1-2 COUNTY- WIDE SWATH OF 8-12 INCHES SNOWFALL JUST ON THE
NORTH SIDE OF THE RAIN/SNOW LINE. MODEL CONSENSUS PUTS THE
MESOSCALE HEAVY SNOW BAND ALONG A LINE FROM MANKATO...THROUGH THE
TWIN CITIES METRO...AND UP THROUGH RICE LAKE WI. THE 12Z SOUNDING
HERE AT MPX THIS MORNING HAD AT LEAST THE WEST METRO COLD ENOUGH
FOR SNOW RIGHT AT THE ONSET OF PRECIP AND THAT`S WHAT WE ARE
SEEING IN SOUTHWEST MN. FORECAST SOUNDINGS ONLY COOL WITH TIME
TODAY...SO ABOVE THE SURFACE WE ARE GOOD TO GO FOR HEAVY SNOW
ALONG THE LINE MENTIONED ABOVE. THE CAVEAT IS THE NEAR SURFACE
LAYER DUE TO DAYTIME HEATING. WE ARE NOW NEAR 40 OR IN THE LOWER
40S...SO THE SNOWFLAKES MAY TURN TO RAINDROPS 500-1000 FT ABOVE
THE GROUND. SO...WE COULD STILL SEE A 2-3 HOUR WINDOW OF RAIN/SNOW
BEFORE THE CHANGE OVER HAPPENS...AND WE QUICKLY FIND OURSELVES WITH
1-2" PER HOUR RATES. THE SNOW GRADIENT WILL BE EXTREMELY TIGHT.
PERHAPS A 7-8" INCH SNOW GRADIENT OVER THE SPAN OF A SINGLE
COUNTY. WE WILL UNDOUBTEDLY MISS IN SOME AREA WITH THIS KIND OF
GRADIENT. THE TIGHTEST GRADIENT SHOULD BE ALONG THE RAIN/SNOW
LINE...BUT TOTALS SHOULD ALSO QUICKLY FALL TO THE NORTHWEST. SO
EVEN PORTIONS OF THE WESTERN TWIN CITIES METRO AND CERTAINLY ST.
CLOUD WILL SEE LESSER TOTALS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 414 AM CDT MON APR 22 2013
MOTHER NATURE IS AT IT AGAIN! MAJOR CHANGES HAVE BEEN MADE TO THE
SHORT TERM WITH REGARDS TO THE SYSTEM WE HAVE BEEN FOLLOWING FOR THE
PAST FEW DAYS. THE 00Z MODEL RUNS...INCLUDING THE GLOBAL ENSEMBLES
AND MESOSCALE MODELS...HAVE REALLY COME INTO LINE IN SHOWING A
QUICK-HITTING MAJOR WINTER STORM TAKING SHAPE LATER THIS AFTERNOON
AND INTO TONIGHT. IN FACT...THE NAM...GFS...CANADIAN... SREF...AND
GEFS MODELS ARE ALL IN VERY GOOD AGREEMENT LEADING TO A RELATIVELY
HIGH CONFIDENCE FORECAST.
LOW PRESSURE WILL TRACK NORTHEAST FROM THE SOUTHERN PLAINS TO
SOUTHWESTERN WISCONSIN BY MIDNIGHT TONIGHT...THEN TO NORTHEAST
WISCONSIN BY EARLY TUESDAY MORNING. A COLD FRONT WILL SINK SOUTH
ACROSS THE AREA AND STALL ACROSS SCTRL MN/WCTRL WI THIS EVENING.
PRECIPITATION WILL SPREAD OVERHEAD FROM THE SOUTHWEST LATER THIS
MORNING OR INTO THE AFTERNOON. IT WILL BEGIN INITIALLY AS SNOW
ACROSS WRN MN...BUT WARMER AIR ALOFT FURTHER EAST WILL KEEP IT RAIN
UNTIL CAA TO THE NORTH AND WEST OF THE SURFACE LOW TURNS IT TO ALL
SNOW. THIS TRANSITION WILL TAKE PLACE AT NEW ULM AROUND 3 PM...TWIN
CITIES AROUND 5 PM...AND NEW RICHMOND/RICE LAKE AROUND 7 PM.
THINK THE ARRIVAL OF THE COLD AIR WILL BE QUICK ENOUGH ALONG
A LINE FROM A NEW ULM...TWIN CITIES...MORA LINE TO KEEP THE MAJORITY
OF SIGNIFICANT PRECIP AS SNOW WITH THIS SYSTEM. LOCATIONS NEAR THE
STALLED FRONT WILL STILL HAVE MARGINAL THERMAL PROFILES...FAVORING
MORE OF A RAIN/SNOW MIX FOR THE MAJORITY OF THE EVENT. THIS WOULD
INCLUDE EAU CLAIRE AND ALBERT LEA.
VERY IMPRESSIVE FRONTOGENESIS WITHIN THE DENDRITIC GROWTH ZONE TAKES
SHAPE EARLY THIS EVENING WITHIN 40 MILES OF THE AFOREMENTIONED LINE.
THUS...THERE SHOULD BE INTENSE BANDING WITHIN THE LARGER DEFORMATION
AREA WITH SNOW RATES OF 1 TO 2+ INCHES PER HOUR SETTING UP. LATE
SEASON SYSTEMS ARE NOTORIOUS FOR PRODUCING THUNDERSNOW...ESPECIALLY
WITH THIS LEVEL OF FRONTOGENESIS SO ALSO MENTIONED ISOLATED
THUNDERSTORMS TONIGHT.
QPF IS VERY SIMILAR ON THE MODELS MENTIONED...AND WENT WITH A
GFS/NAM/SREF COMBO FOR LIQUID. USING ROUGHLY A 10:1 RATIO TONIGHT
YIELDS A GOOD 6 TO 9 INCHES OF SNOW FROM SWRN MN TO ECTRL MN AND
NWRN WI. THE HIGHEST AMOUNTS ARE EXPECTED IN AND NORTHEAST OF THE
TWIN CITIES METRO WHERE THE DEFORMATION BAND WILL REACH ITS MATURE
PHASE. ISSUED A WINTER STORM WARNING FOR THE MOST OF SRN MN AND WRN
WI...WITH A WINTER WEATHER ADVISORY FOR A ROW OF COUNTIES
SURROUNDING THE WARNING WHERE 3 TO 6 INCHES ARE FORECAST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 347 AM CDT MON APR 22 2013
FORECAST BEGINS WITH THE VESTIGES OF THE LAST HEAVY SNOW
EVENT FOR THE WINTER/SPRING SEASON ENDING ON TUESDAY MORNING
OVER WEST CENTRAL WI. COULD BE ANOTHER QUICK FEW TENTHS TO
NEAR ONE HALF INCH OVER THIS REGION FROM 12Z TO 18Z. EXPECT
SOME SLIGHT BLOWING AND DRIFTING OF HEAVY SNOW OVER EAST CENTRAL
MN AND WEST CENTRAL WI DURING THIS TIME FRAME AS WELL...ASSOCIATED
WITH SUSTAINED NORTHERLY WINDS IN THE 10 TO 20 MPH RANGE. NEW
COATING OF 2 TO 8 INCHES OF SNOW WILL PUT A CAP ON MAX READINGS
FOR TUESDAY. CLOUD COVER SHOULD DECREASE MARKEDLY ON TUESDAY NIGHT.
ONLY ELEMENT KEEPING US FROM PLUNGING BACK INTO THE UPPER SINGLE
DIGITS TO MID TEENS TOMORROW NIGHT IS FAIRLY ROBUST PRESSURE
GRADIENT. THAT SAID...TEMPERATURES WILL STILL BE 10 TO NEAR 15
DEGREES BELOW NORMAL FOR MUCH OF THE CWA.
WEAK SURFACE TROUGH AND MODERATE 50H TROUGH JUST TO ITS LEE WILL
BE THE IMPETUS FOR ANOTHER ROUND OF PCPN WED MORNING INTO THE
EVENING HOURS. USED GFS40 285K ISENTROPIC ANAL FOR PLACEMENT
OF PCPN TRENDS. 850 TEMPS AT THIS JUNCTURE PRETTY MUCH GUARANTEEING
MOST OF EVENT WILL BE OF LIQUID VARIETY. ALTHOUGH MOISTURE WILL
BE LACKING WHEN SUB ZERO TEMPS ALOFT ARE PRESENT WED EVENING
...COULD BE ENOUGH MOISTURE AND FORCING STILL PREVALENT TO PRODUCE
A QUICK FEW TENTHS TO JUST OVER ONE HALF INCH OF SNOW ACROSS
MAINLY WEST CENTRAL WI AND PORTION OF EAST CENTRAL MN.
ZONAL FLOW TAKES OVER AGAIN OVER MUCH OF LOWER 48 BY THURSDAY AFTN.
MID LEVEL TROUGH COULD BRING SLT POPS TO MUCH OF FA FRI AFTN/EVE.
ANOTHER SURFACE TROUGH IMPETUS FOR CHANCE POPS ACROSS MUCH OF FA
SATURDAY NIGHT INTO EARLY MONDAY MORNING. FORCING WITH BOTH SYSTEMS
APPEARS TO BE MINIMAL...WITH QPF READINGS MAINLY IN THE TWO TENTHS
OF AN INCH RANGE OR LESS RANGE ANTICIPATED WITH BOTH SYSTEMS. SOUTH
CENTRAL MN COULD ENCOUNTER A FEW TENTHS OF AN INCH MORE LATE SAT
NIGHT...ASSOCIATED WITH ISOLATED THUNDERSTORM ACTIVITY AS INSTABILITY
INCREASES NOTICEABLY.
TEMPERATURES WILL FINALLY BREACH THE 60 DEGREE MARK ACROSS MUCH OF
THE FA ON FRIDAY...AS WAA INCREASES WITH STRONG SOUTHWESTERLY FLOW
THROUGHOUT THE DAY. TEMPERATURES WILL SLOWLY INCREASE RIGHT INTO THE
WEEKEND...AND RIGHT INTO THE LAST WEEK OF APRIL. FAR AND AWAY THE MOST
NEWSWORTHY ITEM OF THE EXTENDED INVOLVES THE LONG AWAITED APPEARANCE
OF A SIGNIFICANT 50H RIDGE OVER THE UPPER MIDWEST...WHICH WILL
COMMENCE OVER THE DAKOTAS NEXT TUESDAY...AND ENCOMPASS MN AND WI
BY NEXT WEDNESDAY. TEMPERATURES SHOULD EASILY LIFT INTO THE 70S
OVER OUR FA DURING THIS PERIOD...WITH EVEN A CHANCE FOR A FEW
80 DEGREE READINGS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 645 AM CDT MON APR 22 2013
CONDITIONS AT TAF ISSUANCE TIME RANGE FROM VFR AT AXN/STC TO MVFR
AT RWF/MSP AND IFR AT RNH/EAU. THE STRATUS HAS BEEN ERODING ACROSS
CENTRAL MN AS DRIER AIR ADVECTS IN. CONFIDENCE IS NOT ALL THAT
HIGH OF THIS DRIER AIR REACHING MSP AND EAU...BUT IT COULD REACH
RNH WHERE A TEMPO HAS BEEN INTRODUCED LATE MORNING. PRECIPITATION
WILL SPREAD INTO WRN MN LATE THIS MORNING...AND ACROSS ERN MN/WRN
WI BY MID AFTERNOON. COLDER AIR WILL SINK SOUTH AS THE LOW
APPROACHES AND SHOULD TURN RA TO SN AT MSP AND RNH AROUND 00Z. EAU
SHOULD KEEP A RA/SN MIX GOING THROUGH THE EVENING. A PERIOD OF
HEAVY SNOW EXPECTED FROM RWF TO MSP AND RNH THIS EVENING WITH 1-2
IN/HR SNOW RATES POSSIBLE. CANNOT RULE OUT A RUMBLE OF THUNDER
EITHER. THE SNOW WILL TAPER OFF OVER MIDNIGHT.
KMSP...MVFR CONDITIONS CURRENTLY...WHICH SHOULD PERSIST FOR JUST
ABOUT THE ENTIRE TAF PERIOD. DRIER AIR ACROSS CENTRAL MN COULD
MAKE IT DOWN TO MSP BRIEFLY THIS MORNING...BUT CONFIDENCE WASNT
HIGH ENOUGH TO MENTION IN THE TAFS YET. RAIN WILL ARRIVE MID
AFTERNOON...AND TURN TO SNOW AROUND 00Z. A PERIOD OF HEAVY SNOW IS
LIKELY THIS EVENING WITH LIFR CONDITIONS...THEN CONDITIONS WILL
IMPROVE AFTER 07Z.
/OUTLOOK FOR KMSP/
TUE...MVFR IN THE MRNG...THEN VFR. NW WINDS 10-15 KTS.
WED...VFR. CHC MVFR/-RASN AFTN. SW WINDS 10-15 KTS.
THU...VFR. W WINDS 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 7 AM CDT
TUESDAY FOR MNZ044-045-050>052-058>061-066-068-069-076.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 7 AM CDT
TUESDAY FOR MNZ043-049.
WINTER WEATHER ADVISORY UNTIL 1 AM CDT TUESDAY FOR MNZ048-
054>057-064.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 AM CDT TUESDAY
FOR MNZ053-062-063-070-077.
WINTER STORM WARNING UNTIL 1 AM CDT TUESDAY FOR MNZ065-067-
073>075-082-083-091.
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM CDT
TUESDAY FOR MNZ078-084-085-092.
WI...WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 AM CDT TUESDAY
FOR WIZ014>016-023.
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM CDT
TUESDAY FOR WIZ024-025-027.
&&
$$
UPDATE...CLF
SHORT TERM...BORGHOFF
LONG TERM...AJZ
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
245 PM EDT MON APR 22 2013
.SYNOPSIS...
AN AREA OF HIGH PRESSURE WILL EXTEND ACROSS THE PIEDMONT TODAY
THROUGH TUESDAY. MEANWHILE A LOW PRESSURE SYSTEM WILL DEVELOP OFF
THE SOUTHEAST COAST TODAY...THEN TRACK NORTHEAST JUST OFF THE EAST
COAST TONIGHT THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 950 AM MONDAY...
A COLD NORTHEASTERLY BREEZE CONTINUES THIS MORNING BETWEEN A STRONG
HIGH PRESSURE RIDGE OVER THE PIEDMONT AND AN AMPLIFYING COASTAL
TROUGH. STRATUS OVER THE COASTAL AREAS IS BEGINNING TO PUSH INLAND
AND 1000-2000 FT CEILINGS ARE SHOWING UP IN A FEW OBSERVATIONS EAST
OF I-95. THIS TREND WILL CONTINUE THROUGHOUT THE DAY AS ANOTHER
SHALLOW UPPER LEVEL DISTURBANCE CROSSES THE AREA THIS AFTERNOON AND
CAUSES WEAK CYCLOGENESIS EAST OF WILMINGTON THIS EVENING. 12Z RAOB
ANALYSIS SHOWS AN EASTERLY 850MB WIND AT KMHX AND KWAL...WHICH THE
LARGER SCALE MODELS WERE FORECASTING TO BE NORTH-NORTHEASTERLY AT
THIS TIME. STRONGER WARM ADVECTION AT 850MB MAY LEAD TO A MORE
AGGRESSIVE INLAND PUSH OF LOW CLOUDS...BUT MOISTURE IS VERY SHALLOW
AND THE RAP MODEL KEEPS MEASURABLE PRECIP MOSTLY EAST OF THE CWA.
THERMAL ADVECTION BELOW 850MB APPEARS TO NEARLY NEUTRAL...BUT
STRENGTHENING NORTHEASTERLY FLOW THIS AFTERNOON WILL STILL KEEP
HIGHS 10-15 DEGREES NORMAL. THUS...THE ONLY CHANGES THIS MORNING
WILL BE TO ADJUST SKY COVER TRENDS AND LOWER HIGHS A COUPLE DEGREES
OVER THE COASTAL PLAIN. HIGHS IN THE MID 50S EAST TO LOWER 60S
WEST. -SMITH
TONIGHT...LOW CLOUDS WILL LINGER AS THE SFC WAVE LIFTS NEWD JUST OFF
THE NC COAST. LOW LEVEL WINDS WILL BECOME MORE NLY VERSUS NELY BY
DAYBREAK. OVERCAST SKIES AND STEADY SFC WINDS WILL MAINTAIN TEMPS IN
THE LOW-MID 40S OVERNIGHT. IF CLOUD DECK THINS/DISSIPATE IN THE
WEST...COULD SEE A FEW SPOTS COOL INTO THE UPPER 30S.
TUESDAY...SFC WAVE OFF THE NC COAST EARLY TUESDAY MORNING WILL LIFT
QUICKLY NWD AS MID LEVEL TROUGH EXITS OFFSHORE. SUBSIDENCE BEHIND
THE DEPARTING SYSTEM AND ADVECTION OF DRIER AIR WILL AID TO
DISSIPATE THE LOW CLOUDS ACROSS THE REGION FROM WEST-TO-EAST.
INCREASING SUN WILL AID TO WARM TEMPS BACK INTO THE 60S TO NEAR 70
IN THE AFTERNOON WITH THE COOLER TEMPS IN THE FAR NORTHERN COASTAL
PLAIN WHICH WILL LIKELY HOLD ONTO SOME DECENT CLOUD COVERAGE UNTIL
MID AFTERNOON.
TUESDAY NIGHT...WEAK HIGH PRESSURE WILL EXTEND ACROSS THE REGION AT
THE SURFACE WHILE S/W RIDGE ALOFT SCOOTS EWD. BACKING W-SW FLOW
BEHIND THE DEPARTING MID LEVEL RIDGE WILL ADVECT MID-HIGH LEVEL
MOISTURE INTO CENTRAL NC. THIS WILL LEAD TO AN INCREASE IN HIGH
CLOUDS BY EARLY WEDNESDAY MORNING. RESIDUAL LOW LEVEL MOISTURE WILL
LIKELY CAUSE PATCHES OF FOG OR LOW CLOUDS TO DEVELOP. HOWEVER IF
HIGH CLOUDS ARRIVE SOONER OR THICKER THAN EXPECTED...THIS WILL DETER
DEVELOPMENT OF SIGNIFICANT FOG/LOW CLOUDS. MIN TEMPS TUESDAY NIGHT
3-6 DEGREES WARMER THAN TONIGHT WITH MIN TEMPS MID-UPPER 40S.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 235 PM MONDAY...
FOR WEDNESDAY: RISING SURFACE DEW POINTS WITHIN FAIRLY STABLE LOW
LEVELS... A DEPARTING SURFACE RIDGE... VERY LIGHT SURFACE FLOW FROM
THE SOUTHWEST... AND A LACK OF CLOUDS ALL SUPPORT AT LEAST PATCHY
FOG HOLDING INTO MID MORNING... ALTHOUGH WITH A BIT MORE MOISTURE
AND STRONGER LOW LEVEL FLOW IN THE TRIAD REGION... STRATUS MAY
DOMINATE HERE. AS THE WEAK SURFACE HIGH SHIFTS OFF THE SOUTHEAST
COAST WEDNESDAY... SOUTHWESTERLY FLOW FLOW WILL STRENGTHEN OVER
CENTRAL NC AHEAD OF THE COLD FRONT PROJECTED TO PUSH INTO WRN NC
EARLY-MID AFTERNOON. WE WILL STILL BE DOMINATED BY THE MID LEVEL
RIDGING AND DRY AIR HOWEVER... WITH A PROMINENT WARM NOSE AT 800-700
MB... SO INSTABILITY WILL BE LOW TO ABSENT AND MUCH OF THE DAY WILL
REMAIN DRY. THE EXCEPTION WILL BE THE TRIAD... WHICH SHOULD SEE A
FEW SHOWERS/STORMS MOVING IN VERY LATE IN THE AFTERNOON...
ACCOMPANYING THE RISING MID LEVEL LAPSE RATES TO OVER 6 C/KM AND THE
INCREASING LOW LEVEL MOISTURE TRANSPORT. BUT WITH THE MID LEVEL
VORTICITY SHEARING OFF QUICKLY NE ALONG THE APPALACHIANS ALONG WITH
THE MEAGER LOW LEVEL JET (JUST 20-25 KTS)... ANY PRECIP SHOULD BE
VERY LIGHT AND PATCHY. SREF PROBABILITIES OF MEASURABLE RAIN SUPPORT
THIS WITH ONLY LOW CHANCES GETTING INTO THE NW CWA TOWARD EVENING.
ABOVE-NORMAL THICKNESSES (PROJECTED TO CLIMB ABOVE 1380 METERS)
TEMPERED BY INCREASING HIGH CLOUDS THROUGH THE DAY AND SCATTERED
FLAT CUMULUS IN THE AFTERNOON SUPPORT HIGHS OF 74-80... VALUES ALSO
INDICATED BY THE DRY ADIABATIC LOW LEVEL THERMAL STRUCTURE.
FOR WEDNESDAY NIGHT/THURSDAY: AS THE MID LEVEL FLOW OVER OUR REGION
BECOMES ROUGHLY PARALLEL TO THE SURFACE FRONT... BETWEEN THE FIRST
SHORTWAVE TROUGH THAT SHEARS TO THE NORTHEAST TOWARD SE CANADA AND
THE SECOND SHOT OF SHORTWAVE ENERGY WHICH CROSSES THE UPPER MIDWEST
AND GREAT LAKES...THE SURFACE FRONT IS LIKELY TO MAKE ONLY A VERY
SLOW SOUTHEASTWARD PROGRESSION ACROSS NC WEDNESDAY NIGHT INTO EARLY
THURSDAY. GIVEN THE ANAFRONTAL STRUCTURE TO THIS SYSTEM... WE SHOULD
SEE RAIN AND A FEW STORMS SPREADING SLOWLY EAST WEDNESDAY NIGHT JUST
BEHIND THE FRONT. THE MID LEVEL VORTICITY AND LOW LEVEL JET BOTH
SHEARING OFF TO OUR NORTHEAST... ALONG WITH THE UPPER DIVERGENCE
MAX... WILL RESULT IN WANING DYNAMIC FORCING FOR ASCENT. BUT
STEEPENING MID LEVEL LAPSE RATES (TO OVER 6.25 C/KM) AND THE
POTENTIAL FOR ELEVATED CONVECTION (MUCAPE OF 100-200 J/KG) SHOULD
OFFSET THIS ENOUGH FOR CHANCE POPS... GIVEN THE ANTICIPATED CLIMB IN
PRECIP WATER VALUES TO AROUND 1.25 IN. WILL FOCUS THE HIGHEST POPS
LATE WEDNESDAY EVENING THROUGH EARLY THURSDAY MORNING OVER THE WRN
AND NRN PIEDMONT... BUT WILL LIMIT POPS TO JUST CHANCE. SREF
PROBABILITIES OF MEASURABLE RAIN START OFF NEAR 50% OVER THE
MOUNTAINS WEDNESDAY EVENING BUT FALL OFF QUICKLY WEDNESDAY NIGHT AS
THE FRONT SWEEPS EASTWARD... FURTHER SUPPORTING KEEPING POPS AND
AMOUNTS ON THE LOW END. PRECIP SHOULD TAPER OFF TO PATCHY DRIZZLE
LATE WEDNESDAY NIGHT (IN NW) THROUGH THURSDAY MORNING AS THE MID
LEVEL DRY OUT A BIT. AS THE MID LEVEL TROUGH MOVES THROUGH THE GREAT
LAKES INTO THE ST LAWRENCE VALLEY AND HELPS KICK THE SURFACE-850 MB
FRONTAL ZONE TO OUR SE THURSDAY AFTERNOON... MODEL FORECAST
SOUNDINGS SHOW ENOUGH DRYING JUST OFF THE SURFACE WITH AN INCREASING
DOWNSLOPE COMPONENT FOR SLOWLY CLEARING SKIES WEST-TO-EAST IN THE
AFTERNOON. HOWEVER.. CONFIDENCE IN SUCH CLEARING IS USUALLY REDUCED
IN THESE SITUATIONS WITH A MESOHIGH BEHIND AN ANAFRONT... AS THE
FLOW IS TYPICALLY TOO LIGHT AND VERTICAL MOTIONS TOO WEAK TO
DISPERSE THE RESIDUAL LOW LEVEL MOISTURE. AS A RESULT WILL BE MORE
PESSIMISTIC WITH CLOUD COVER THURSDAY... AND WILL HOLD ONTO THE
EARLIER FORECAST OF BELOW NORMAL TEMPS... ALTHOUGH A GREATER
DURATION OF LOW LEVEL DOWNSLOPE COMPONENT FLOW SHOULD YIELD SOME
AFTERNOON RECOVERY IN THE WRN FORECAST AREA... PLUS THE BRUNT OF THE
COOLER POST-FRONTAL AIR WILL BE SLOWED BY THE MOUNTAINS. MORNING
LOWS 50-58. HIGHS 64-72. -GIH
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 245 PM MONDAY...
FOR THURSDAY NIGHT THROUGH FRIDAY NIGHT: THE MID LEVEL TROUGH AXIS
WILL PUSH TO OUR EAST THURSDAY NIGHT WITH THE COLD FRONT SLIPPING TO
OUR SOUTHEAST... AS A LARGE HIGH PRESSURE AREA BUILDS IN FROM THE
MISS VALLEY. EXPECT GRADUALLY CLEARING SKIES OVERNIGHT... ALTHOUGH
FORECAST SOUNDINGS SUGGEST THAT SHALLOW FOG BANKS ARE POSSIBLE.
PLEASANT AND DRY WEATHER AND SLIGHTLY BELOW-NORMAL TEMPS SHOULD
FOLLOW ON FRIDAY AS THE SURFACE HIGH RIDGES INTO NC WHILE ITS CENTER
CROSSES THE OHIO VALLEY HEADING TOWARD THE MIDATLANTIC REGION.
MODELS SHOW THE HIGH SHIFTING NE OFF THE MIDATLANTIC COAST TO NEW
ENGLAND FRIDAY NIGHT... PROPELLED BY ANOTHER SHORTWAVE TROUGH
CROSSING THE CENTRAL CONUS. THE ENSUING RETURN FLOW FROM THE
SOUTHEAST ALONG WITH INCREASING MID-HIGH LEVEL MOISTURE FROM THE WSW
SHOULD BRING AN INCREASE IN CLOUDS THROUGH FRIDAY NIGHT. TEMPS ABOUT
A CATEGORY BELOW NORMAL.
FOR SATURDAY THROUGH MONDAY: HIGH DEGREE OF FORECAST UNCERTAINTY AS
THE GFS/ECMWF BEGIN TO DIFFER CONSIDERABLY REGARDING THE CENTRAL US
TROUGH. BOTH INDICATE A POSITIVE TILT TO THE TROUGH ON SATURDAY...
BUT THE ECMWF EVOLVES INTO A SPLIT FLOW WITH A MORE AMPLIFIED AND
SLOWER WAVE THROUGH THE PLAINS COMPARED TO THE GFS. THE ECMWF THEN
DEVELOPS THIS INTO A CLOSED LOW TO OUR NORTH WITH A TROUGH COVERING
THE EASTERN CONUS SATURDAY NIGHT THROUGH MONDAY... WHILE THE GFS
TAKES THE WEAKER WAVE SWIFTLY OFFSHORE SUNDAY WITH MID LEVEL RIDGING
BUILDING OVER THE EASTERN CONUS BY MONDAY. RECENT GFS RUNS HAVE BEEN
TRENDING MORE AMPLIFIED AND SLOWER WITH THE WAVE... AND IT MAY BE
TOO EASILY KEEPING THE STREAMS PHASED... SO A LEAN TOWARD THE ECMWF
IS PREFERRED. THIS WILL MEAN A SLOWLY APPROACHING TROUGH FROM THE
WEST THROUGH MONDAY... RESULTING IN RAIN CHANCES FROM SATURDAY NIGHT
INTO MONDAY. THE OFFSHORE-DRIFTING SURFACE HIGH MAY DEPOSIT ENOUGH
COOL AIR IN THE PIEDMONT FOR AN IN SITU DAMMING EVENT. WILL LEAVE
TEMPS BELOW NORMAL THROUGH THE PERIOD... WITH SOME REBOUND IN TEMPS
MONDAY AS AN EDGE BACK TOWARD CLIMATOLOGY WITH A POSSIBLE WEAKENING
OF ANY WEDGE AIR MASS. -GIH
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 140 PM MONDAY...
DESPITE QUITE A BIT OF LOW LEVEL MOISTURE ALONG THE NC COAST AND A
STEADY 10-15KT NORTHEASTERLY WIND...LOW CLOUDS HAVE STRUGGLED TO
MOVE INLAND PAST THE I-95 CORRIDOR TODAY. KRWI AND KFAY HAVE
REPORTED PERIODS OF MVFR CEILINGS...TYPICALLY LASTING NO LONGER THAN
THAN AN HOUR OR TWO. BECAUSE OF THIS...CONFIDENCE IS BELOW AVERAGE
REGARDING WHEN LOW CLOUDS WILL SPREAD WEST TO KRDU AND EVENTUALLY
KGSO/KINT TONIGHT. EXPECT CEILINGS WILL REDEVELOP AT KRWI AND KFAY
BY THIS EVENING AS A LOW PRESSURE DEVELOPS OFFSHORE AND MOVES ALONG
THE COAST...LOWERING BELOW 2000FT AROUND MIDNIGHT AND REMAINING
THERE UNTIL LATE TUESDAY MORNING. FURTHER WEST...MVFR CEILINGS WILL
BE A LITTLE HIGHER AT KRDU BUT SHOULD STILL FALL BELOW 2000 FT BY
09Z. AT KGSO/KINT...CEILINGS MAY HOLD AT 2500 FT AND SCATTER OUT BY
MID MORNING AS THE SURFACE LOW MOVES NORTHEAST AWAY FROM THE AREA.
SURFACE WINDS WILL REMAIN UP OVERNIGHT...RANGING FROM 6-8KT IN THE
WEST TO AS HIGH AS 12-14KT IN THE EAST.
OUTLOOK...
AN APPROACHING FRONTAL SYSTEM WILL BRING THE NEXT CHANCE FOR SUB-VFR
CONDITIONS WEDNESDAY NIGHT INTO THURSDAY. IMPROVING AVIATION
CONDITIONS ANTICIPATED THURSDAY NIGHT INTO FRIDAY AS HIGH PRESSURE
BUILDS INTO THE REGION FROM THE NORTHWEST.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS/SMITH
SHORT TERM...HARTFIELD
LONG TERM...HARTFIELD
AVIATION...WSS/SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
140 PM EDT MON APR 22 2013
.SYNOPSIS...
AN AREA OF HIGH PRESSURE WILL EXTEND ACROSS THE PIEDMONT TODAY
THROUGH TUESDAY. MEANWHILE A LOW PRESSURE SYSTEM WILL DEVELOP OFF
THE SOUTHEAST COAST TODAY...THEN TRACK NORTHEAST JUST OFF THE EAST
COAST TONIGHT THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 950 AM MONDAY...
A COLD NORTHEASTERLY BREEZE CONTINUES THIS MORNING BETWEEN A STRONG
HIGH PRESSURE RIDGE OVER THE PIEDMONT AND AN AMPLIFYING COASTAL
TROUGH. STRATUS OVER THE COASTAL AREAS IS BEGINNING TO PUSH INLAND
AND 1000-2000 FT CEILINGS ARE SHOWING UP IN A FEW OBSERVATIONS EAST
OF I-95. THIS TREND WILL CONTINUE THROUGHOUT THE DAY AS ANOTHER
SHALLOW UPPER LEVEL DISTURBANCE CROSSES THE AREA THIS AFTERNOON AND
CAUSES WEAK CYCLOGENESIS EAST OF WILMINGTON THIS EVENING. 12Z RAOB
ANALYSIS SHOWS AN EASTERLY 850MB WIND AT KMHX AND KWAL...WHICH THE
LARGER SCALE MODELS WERE FORECASTING TO BE NORTH-NORTHEASTERLY AT
THIS TIME. STRONGER WARM ADVECTION AT 850MB MAY LEAD TO A MORE
AGGRESSIVE INLAND PUSH OF LOW CLOUDS...BUT MOISTURE IS VERY SHALLOW
AND THE RAP MODEL KEEPS MEASURABLE PRECIP MOSTLY EAST OF THE CWA.
THERMAL ADVECTION BELOW 850MB APPEARS TO NEARLY NEUTRAL...BUT
STRENGTHENING NORTHEASTERLY FLOW THIS AFTERNOON WILL STILL KEEP
HIGHS 10-15 DEGREES NORMAL. THUS...THE ONLY CHANGES THIS MORNING
WILL BE TO ADJUST SKY COVER TRENDS AND LOWER HIGHS A COUPLE DEGREES
OVER THE COASTAL PLAIN. HIGHS IN THE MID 50S EAST TO LOWER 60S
WEST. -SMITH
TONIGHT...LOW CLOUDS WILL LINGER AS THE SFC WAVE LIFTS NEWD JUST OFF
THE NC COAST. LOW LEVEL WINDS WILL BECOME MORE NLY VERSUS NELY BY
DAYBREAK. OVERCAST SKIES AND STEADY SFC WINDS WILL MAINTAIN TEMPS IN
THE LOW-MID 40S OVERNIGHT. IF CLOUD DECK THINS/DISSIPATE IN THE
WEST...COULD SEE A FEW SPOTS COOL INTO THE UPPER 30S.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 305 AM MONDAY...
TUESDAY...SFC WAVE OFF THE NC COAST EARLY TUESDAY MORNING WILL LIFT
QUICKLY NWD AS MID LEVEL TROUGH EXITS OFFSHORE. SUBSIDENCE BEHIND
THE DEPARTING SYSTEM AND ADVECTION OF DRIER AIR WILL AID TO
DISSIPATE THE LOW CLOUDS ACROSS THE REGION FROM WEST-TO-EAST.
INCREASING SUN WILL AID TO WARM TEMPS BACK INTO THE 60S TO NEAR 70
IN THE AFTERNOON WITH THE COOLER TEMPS IN THE FAR NORTHERN COASTAL
PLAIN WHICH WILL LIKELY HOLD ONTO SOME DECENT CLOUD COVERAGE UNTIL
MID AFTERNOON.
TUESDAY NIGHT...WEAK HIGH PRESSURE WILL EXTEND ACROSS THE REGION AT
THE SURFACE WHILE S/W RIDGE ALOFT SCOOTS EWD. BACKING W-SW FLOW
BEHIND THE DEPARTING MID LEVEL RIDGE WILL ADVECT MID-HIGH LEVEL
MOISTURE INTO CENTRAL NC. THIS WILL LEAD TO AN INCREASE IN HIGH
CLOUDS BY EARLY WEDNESDAY MORNING. RESIDUAL LOW LEVEL MOISTURE WILL
LIKELY CAUSE PATCHES OF FOG OR LOW CLOUDS TO DEVELOP. HOWEVER IF
HIGH CLOUDS ARRIVE SOONER OR THICKER THAN EXPECTED...THIS WILL DETER
DEVELOPMENT OF SIGNIFICANT FOG/LOW CLOUDS. MIN TEMPS TUESDAY NIGHT
3-6 DEGREES WARMER THAN TONIGHT WITH MIN TEMPS MID-UPPER 40S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 305 AM MONDAY...
WEDNESDAY THROUGH THURSDAY NIGHT:
THE NEXT SYSTEM WILL QUICKLY MOVE INTO THE AREA LATE WEDNESDAY INTO
WEDNESDAY NIGHT... LINGERING INTO THURSDAY. HOWEVER... WITH A
SOUTHERLY RETURN FLOW DEVELOPING ON WEDNESDAY MORNING... THERE WILL
BE LITTLE TIME FOR LOW LEVEL MOISTURE RECOVERY. GIVEN THE BEST
DYNAMICS WITH THE SYSTEM ARE EXPECTED TO PASS TO THE NORTH OF THE
REGION... WITH GENERALLY WEST TO WEST-SOUTHWESTERLY MID LEVEL
FLOW... OVERALL MOISTURE TRANSPORT DOES NOT LOOK OVERLY IMPRESSIVE
WITH THIS SYSTEM. THUS... CHANCES FOR ANY SVR STORMS LOOKS TO VERY
LOW. INSTEAD EXPECT A BAND OF SHOWERS AND MAYBE A FEW STORMS TO MOVE
INTO NORTHERN PORTIONS OF THE AREA ON WEDNESDAY... WITH A DECENT MID
LEVEL CAP GENERALLY HOLDING FOR THE DAYLIGHT HOURS ON WEDNESDAY.
EXPECT THE COLD FRONT SHOULD BEGIN SLOWLY SINKING
SOUTH-SOUTHEASTWARD THROUGH THE AREA OVERNIGHT WEDNESDAY/THURSDAY
MORNING... WITH THE FRONT EXPECTED TO BE LOCATED ACROSS OUR
SOUTHERN/SOUTHEASTERN COUNTIES BY 12Z THURSDAY BEFORE EVENTUALLY
PUSHING SOUTH OF THE AREA SOMETIME LATE THURSDAY MORNING/AFTERNOON.
A BULK OF THE SHOWERS MAY BE MORE ANAFRONTAL AND ASSOCIATED MORE
WITH THE 925-850 MB FRONT AND SECONDARY S/W TROUGH EXPECTED TO CROSS
THE AREA ON THURSDAY. FOR NOW WILL SHOW LIKELY POPS FROM AROUND
MIDNIGHT THURSDAY ACROSS THE NORTHWESTERN HALF OF THE AREA UNTIL
AROUND NOON FOR THE SOUTHEASTERN/EASTERN HALF OF THE CWA... WITH
SHOWERS POSSIBLY LINGERING INTO THE AFTERNOON ACROSS OUR EASTERN AND
SOUTHEASTERN COUNTIES. BEHIND THE EXITING S/W THURSDAY AFTERNOON
EXPECT DRIER AIR TO ADVECT INTO THE AREA AT THE SURFACE AND ALOFT.
WAA AHEAD OF THE FRONT SHOULD LEAD TO AFTERNOON LOW LEVEL THICKNESS
VALUES SOARING INTO THE 1380S... POSSIBLY 1390S ON WEDNESDAY
AFTERNOON. EVEN WITH THE INCREASING CLOUD COVER EXPECT HIGH TEMPS
SHOULD BE IN THE MID TO UPPER 70S... WITH A FEW LOCATIONS ACROSS THE
SOUTH AND EAST TOUGHING 80 DEGREES. GIVEN THE POSSIBLE ANAFRONTAL
PRECIP BY EARLY THURSDAY MORNING AND DURING THE DAY ON THURSDAY...
LOW AND HIGH TEMPS WILL BE VERY TRICKY AND DEPENDENT ON THE TIMING
OF THE FRONT...QPF... AND HOW MUCH OF A SURGE OF DRY AIR AT THE
SURFACE MAKES IT INTO THE AREA BEHIND THE FRONT WHILE PRECIP IS
STILL EXPECTED. WRT THE TIMING OF THE FRONT THE 00Z NAM AND GFS ARE
PRETTY CONSISTENT SHOWING THE FRONT ACROSS OUR FAR
SOUTHERN/SOUTHEASTERN COUNTIES BY 12Z THURSDAY... WITH THE 12Z ECMWF
A BIT FARTHER TO THE NORTH (BUT NOT MUCH... MAYBE A ROW OF COUNTIES
FURTHER NORTH). WILL USE A BEND OF THE 12Z ECMWF AND 00Z GFS.
THUS... WILL GO WITH LOW TEMPS BY THURSDAY MORNING RANDING FROM
AROUND 50 NORTH TO THE LOWER 60S FAR SOUTH. HIGH TEMPS WILL BE QUITE
TRICKY FOR THURSDAY AFTERNOON AND BE DRIVEN LARGELY BY THE QPF AND
IF WE SEE ANY CLEARING ACROSS THE WEST IN THE AFTERNOON. WILL GO ON
THE COOL SIDE OF THE GUIDANCE... ESPECIALLY ACROSS THE
EASTERN/NORTHEASTERN PORTION OF THE CWA WHERE SHOWERS AND CLOUD
COVER WILL LIKELY LINGER THE LONGEST. THIS YIELDS HIGH RANGING FROM
NEAR 60 NE TO AROUND 70 ACROSS THE FAR SOUTH (VERY LOW CONFIDENCE
TEMP FORECAST). WITH SURFACE HIGH PRESSURE BUILDING INTO THE AREA ON
THURSDAY NIGHT/FRIDAY MORNING EXPECT CLEARING SKIES... WITH MUCH
COOLER TEMPS EXPECTED BY FRIDAY MORNING. EXPECT LOW TEMPS FRIDAY
MORNING WILL BE GENERALLY IN THE 40S... WITH MAYBE EVEN A FEW OF THE
USUAL COLD SPOTS ACROSS THE NORTH PIEDMONT DROPPING TO AROUND 40
DEGREES.
FRIDAY THROUGH SUNDAY:
VERY BRIEF S/W RIDGING WILL BUILD ACROSS THE AREA FRIDAY/FRIDAY
EVENING... BEFORE THE NEXT DISTURBANCE APPROACHES THE AREA FROM THE
SW IN GENERAL BROAD CYCLONIC FLOW ACROSS THE CONUS. MEDIUM RANGE
MODELS ARE STRUGGLING WITH THE STRENGTH AND PROGRESSION OF THIS S/W
TROUGH. WILL FOLLOW CLOSE TO WPC FOR NOW AND HEDGE TOWARDS THE
SLOWER SIDE OF GUIDANCE. THIS SCENARIO GENERALLY KEEPS THE AREA DRY
FOR SATURDAY... WITH SHOWERS/RAIN EXPECTED SATURDAY NIGHT INTO
SUNDAY... WITH POSSIBLY SOME FORM OF DAMMING AIRMASS. TEMPS DURING
THIS PERIOD ARE EXPECTED TO RUN SLIGHTLY BELOW NORMAL TO POSSIBLY
WELL BELOW NORMAL IN THE HEART OF THE DAMMING REGION WITH PRECIP
SPREADING INTO THE AREA AND THE SURFACE RIDGE AXIS EXTENDING BACK
INTO OUR AREA FROM THE NORTHEAST ON SUNDAY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 140 PM MONDAY...
DESPITE QUITE A BIT OF LOW LEVEL MOISTURE ALONG THE NC COAST AND A
STEADY 10-15KT NORTHEASTERLY WIND...LOW CLOUDS HAVE STRUGGLED TO
MOVE INLAND PAST THE I-95 CORRIDOR TODAY. KRWI AND KFAY HAVE
REPORTED PERIODS OF MVFR CEILINGS...TYPICALLY LASTING NO LONGER THAN
THAN AN HOUR OR TWO. BECAUSE OF THIS...CONFIDENCE IS BELOW AVERAGE
REGARDING WHEN LOW CLOUDS WILL SPREAD WEST TO KRDU AND EVENTUALLY
KGSO/KINT TONIGHT. EXPECT CEILINGS WILL REDEVELOP AT KRWI AND KFAY
BY THIS EVENING AS A LOW PRESSURE DEVELOPS OFFSHORE AND MOVES ALONG
THE COAST...LOWERING BELOW 2000FT AROUND MIDNIGHT AND REMAINING
THERE UNTIL LATE TUESDAY MORNING. FURTHER WEST...MVFR CEILINGS WILL
BE A LITTLE HIGHER AT KRDU BUT SHOULD STILL FALL BELOW 2000 FT BY
09Z. AT KGSO/KINT...CEILINGS MAY HOLD AT 2500 FT AND SCATTER OUT BY
MID MORNING AS THE SURFACE LOW MOVES NORTHEAST AWAY FROM THE AREA.
SURFACE WINDS WILL REMAIN UP OVERNIGHT...RANGING FROM 6-8KT IN THE
WEST TO AS HIGH AS 12-14KT IN THE EAST.
OUTLOOK...
AN APPROACHING FRONTAL SYSTEM WILL BRING THE NEXT CHANCE FOR SUB-VFR
CONDITIONS WEDNESDAY NIGHT INTO THURSDAY. IMPROVING AVIATION
CONDITIONS ANTICIPATED THURSDAY NIGHT INTO FRIDAY AS HIGH PRESSURE
BUILDS INTO THE REGION FROM THE NORTHWEST.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS/SMITH
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...WSS/SMITH
AREA FORECAST DISCUSSION
NWS TULSA OK
1221 PM CDT MON APR 22 2013
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
ELEVATED SHOWERS EARLY THIS AFTERNOON MAY AFFECT KBVO.
ADDITIONAL THUNDERSTORMS ARE EXPECTED TO AFFECT AREA
TAF SITES THIS EVENING AND INTO TUESDAY MORNING AS A COLD
FRONT MOVES THROUGH THE AREA. MVFR CEILINGS WILL DEVELOP
BEHIND THE COLD FRONT.
&&
.PREV DISCUSSION... /ISSUED 1048 AM CDT MON APR 22 2013/
DISCUSSION...
ELEVATED SHOWERS HAVE DEVELOPED ACROSS NORTH-CENTRAL OKLAHOMA AND
INTO OSAGE AND PAWNEE COUNTIES IN NORTHEAST OKLAHOMA. THIS ACTIVITY
WILL MOVE OFF TO THE NORTHEAST THROUGH THE REMAINDER OF THE MORNING
AND EARLY AFTERNOON. LOCAL MODELS AND THE LATEST HRRR KEEP SURFACE
BASED CONVECTION ALONG THE FRONT WHICH IS CURRENTLY ADVANCING INTO
NORTHERN KANSAS. THIS ACTIVITY LOOKS TO AFFECT NORTHEAST OKLAHOMA
AFTER 00Z.
TEMPERATURES LOOKS TO BE REASONABLE AND HAVE ONLY MADE SIGNIFICANT
ADJUSTMENTS TO THE SKY...POP AND WX GRIDS FOR TODAY.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...10
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
341 PM CDT MON APR 22 2013
.SHORT TERM...
A STRONG COLD FRONT LOOKING TO BE A LITTLE AHEAD OF SCHEDULE HAVING
ALREADY NOSED INTO THE OKLAHOMA PANHANDLE AS OF 19Z...ALTHOUGH THE
COLD AIR LAGGING THE INITIAL WIND SHIFT BY ABOUT 150 TO 200 MILES.
MORNING RAP RUNS FASTEST WITH THE FRONT LOOK TO BE THE MODEL TO LEAN
TOWARD...AND POSSIBLY SLIGHTLY FASTER THAN THAT. WINDS WILL LIKELY
ACCELERATE TOWARD ADVISORY CRITERIA WITH PRESSURE RISES BEHIND IT...
ALTHOUGH FOR NOW WILL KEEP SPEEDS JUST BELOW THAT LEVEL. WILL RUN
WITH LOW TEMPS JUST BELOW LOW END OF MOS NUMBERS GIVEN STRENGTH OF
THE COLD AIR. THAT WOULD PUT POTENTIAL FOR A LIGHT FREEZE ACROSS THE
EXTREME SW PANHANDLE WHERE JUST NOW REACHING AVG DATE TO THE
BEGINNING OF THE GROWING SEASON. BETTER CANDIDATE FOR FREEZE PRODUCT
TO COME TUESDAY NIGHT WITH POTENTIAL FOR A HARD FREEZE. LOW CLOUDS
TO FILTER IN BEHIND THE FRONT. WHILE LOW CLOUDS PROGGED TO LIFT
TUESDAY MORNING...PERSISTENT MID LEVEL MOISTURE SHOULD KEEP SOME
CLOUD COVER OVER THE AREA. THAT COMBINED WITH LOW LEVEL COLD
ADVECTION THROUGH THE DAY WILL RESULT IN A DIURNAL RANGE OF 10 TO 15
DEGREES. OTHER ISSUE IS CHANCE FOR LIGHT PRECIP IN POST-FRONTAL AIR
MASS LATE TONIGHT AND EARLY TUESDAY. LOW LEVEL FRONTOGENESIS MAY BE
SUFFICIENT TO GENERATE SOME DRIZZLE OR VERY LIGHT RAIN ACROSS THE
NERN ZONES...BUT MEASURABLE PRECIP CHANCES LOOK VERY SLIM WITH BEST
LIFT ASSOCIATED WITH MID LEVEL TROUGH/JET REMAINING NORTH OF THE
FCST AREA. FINALLY...WHILE COLD FRONT WILL BE MOVING INTO AIR WITH
DEW POINTS IN THE 40S AND THUS SOME CAPE...CAP STRENGTH LOOKS TO BE
VERY STRONG WITH LITTLE POTENTIAL THAT ENERGY CAN BE RELEASED.
&&
.LONG TERM...
THE PRIMARY CONCERN FOR TUESDAY NIGHT AND WEDNESDAY MORNING WILL BE
THE POTENTIAL FOR A WIDESPREAD FREEZE ON THE HEELS OF THE PREVIOUS
NIGHTS FROPA. MODELS SEEM TO AGREE THAT H850 TEMPS WILL SETTLE
SOMEWHERE BETWEEN 0 TO -3 DEGREES... WITH THE NAM BEING THE COLD
OUTLIER OF THE BUNCH. IN ADDITION... A 1025-1030MB SURFACE RIDGE
WILL SLIDE JUST TO THE NE OF THE AREA OVERNIGHT...WHICH WILL KEEP
WINDS VERY LIGHT. ON THE OTHER HAND... SOME LINGERING JET ENERGY
AND MID-LEVEL MOISTURE COULD KEEP A BIT OF CLOUD COVER IN THE
AREA... INHIBITING RADIATIONAL COOLING IN SOME SPOTS... PARTICULARLY
IN THE EASTERN ZONES. REGARDLESS... CLOUD COVER SHOULD BREAK UP
BEFORE SUNRISE... AND TEMPERATURES ACROSS THE CAPROCK WILL LIKELY
FALL TO AROUND 4-8 DEGREES BELOW FREEZING BEFORE ALL IS SAID AND
DONE. TEMPERATURES WILL GRADUALLY RISE WEDNESDAY AND THURSDAY AHEAD
OF AN APPROACHING WAVE... WHICH WILL BE OUR NEXT ITEM OF CONCERN.
BY THURSDAY... A MEANDERING CLOSED LOW WILL WORK ITS WAY EASTWARD
FROM THE SUBTROPICAL PACIFIC BEFORE OPENING UP AND PHASING WITH A
BROAD CENTRAL CONUS TROUGH. BEFORE COMPLETELY BEING ABSORBED...
THIS WAVE WILL TRAVERSE THE TX PANHANDLE SOMETIME LATE THURSDAY
NIGHT... ALTHOUGH THERE IS STILL ABOUT 6 HOURS OF DISAGREEMENT
BETWEEN THE THE GFS AND ECMWF. AHEAD OF THIS WAVE... PRESSURE FALLS
ACROSS THE SOUTHERN FRONT RANGE WILL BEGIN TO FORCE SOUTHERLY FLOW
ACROSS TX...AND IN TURN ALLOW MODEST MOISTURE TO RETURN TO THE SOUTH
PLAINS AND EASTERN NM. DUE TO TUESDAYS COLD FRONT PINNING DEEP
MOISTURE WELL TO THE SOUTH... THE TIMING AND EXTENT OF THIS MOISTURE
RETURN IS IN QUESTION... AND AT THIS TIME IT APPEARS THAT THE BEST
MOISTURE WILL STRUGGLE TO ARRIVE UNTIL OVERNIGHT THURSDAY AND EVEN
EARLY FRIDAY MORNING. IN ADDITION... A STOUT CAP AND LOW-LEVEL
STRATUS WILL LIKELY ELIMINATE THE POSSIBILITY FOR AFTERNOON
THUNDERSTORM INITIATION EXCEPT FOR POSSIBLY ALONG THE
DRYLINE/PACIFIC FRONT IN EASTERN NM. AS THE WAVE PROGRESSES
EASTWARD... A PACIFIC FRONT WILL ALSO PUSH EASTWARD AND LIKELY
TRAVERSE THE AREA VERY LATE THURSDAY/EARLY FRIDAY...ALTHOUGH AGAIN
THE TIMING OF THIS FEATURE IS STILL SOMEWHAT IN QUESTION. AS THIS
FRONT MOVES EAST... IMPROVING MOISTURE ACROSS THE SOUTH PLAINS COULD
YIELD AT MARGINAL CHANCES FOR SHOWER/THUNDERSTORM
DEVELOPMENT...MOSTLY ACROSS THE NORTHERN ZONES WITH THE ADDED
FORCING FROM THE FRONT AND PASSING WAVE.
BEYOND FRIDAY MORNING... MODEL SOLUTIONS DIVERGE SIGNIFICANTLY...
ALTHOUGH THE GENERAL TREND WILL BE FOR BUILDING HEIGHTS AND WARMER
TEMPERATURES THROUGH THE END OF THE WEEK AND INTO THE
WEEKEND....FOLLOWING A BENIGN COLD FRONT FRIDAY NIGHT/SATURDAY
MORNING. MODELS ARE NOT IN AGREEMENT REGARDING THE ADVANCEMENT OF
THIS FRONT... AS THE ECMWF SENDS IT WELL SOUTH INTO THE TRANS PECOS
REGION WHILE THE GFS STALLS IT HALFWAY THROUGH THE LBB CWA. GIVEN
THE WEAKENING STATE OF THE PASSING WAVE AND LACK OF SIGNIFICANT COLD
ADVECTION... GFS SEEMS MORE REASONABLE HERE... ALTHOUGH CONVECTIVE
SIGNAL IN GFS FOR SUNDAY AFTERNOON SEEMS SUSPECT GIVEN THE ANEMIC
UPPER FLOW AND LACK OF FORCING. BOTH MODELS SEEM TO HINT AT A
SLOW-APPROACHING TROUGH/CLOSED LOW SOMETIME EARLY NEXT WEEK... BUT
AT THIS POINT SOLUTIONS ARE TOO FAR APART AND TOO FAR AWAY TO PUT
MUCH STOCK IN.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 30 45 25 59 36 / 10 10 10 0 10
TULIA 31 46 26 60 38 / 10 10 10 0 10
PLAINVIEW 32 48 27 60 38 / 10 10 10 0 10
LEVELLAND 35 50 28 60 38 / 10 10 10 0 10
LUBBOCK 35 50 30 60 39 / 10 10 10 0 10
DENVER CITY 39 54 26 61 33 / 10 10 10 0 10
BROWNFIELD 38 51 28 61 35 / 10 10 10 0 10
CHILDRESS 36 48 33 62 40 / 10 10 10 0 10
SPUR 39 49 32 61 44 / 10 10 10 0 10
ASPERMONT 43 50 33 62 43 / 10 10 10 0 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07/16
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
108 PM CDT MON APR 22 2013
.AVIATION...
FOR THE 18Z TAFS...THE TIMING OF AN UNSEASONABLY STRONG COLD FRONT
THROUGH AREA AIRPORTS IS THE PRIMARY CONCERN.
LATEST MODEL GUIDANCE INDICATES THAT THE FRONT WILL MOVE THROUGH
THE DFW AREA IN THE 14 TO 16Z TIMEFRAME. HAVE 14Z FOR THE WESTERN
TAFS AND 15Z FOR THE EASTERN SITES. WE WILL BE ABLE TO REFINE THE
TIMING OF THE FRONT ONCE IT GETS CLOSER TO NORTH TX AND WE CAN
TRACK ITS SOUTHWARD MOVEMENT. EXPECT AREAS OF LIGHT RAIN OR
DRIZZLE TO PERSIST ALONG AND BEHIND THE FRONTAL BOUNDARY TOMORROW.
BETWEEN THE VERY LIGHT PRECIPITATION AND THE LOW-LEVEL COLD AIR
ADVECTION BEHIND THE FRONT...EXPECT CLOUDS TO REMAIN AT LOW MVFR
LEVELS THRU MUCH OF THE DAY WHICH IS ABNORMAL FOR LATE APRIL. CIGS
MAY CLIMB BRIEFLY ABOVE 2 KFT IN THE LATE AFTERNOON HRS...BUT WILL
LIKELY FALL BACK BELOW 2 KFT TUESDAY EVENING.
OTHERWISE...EXPECT THAT MVFR STRATUS WILL BUILD OVER AREA AIRPORTS
AFTER MIDNIGHT TONIGHT AS SLIGHTLY DEEPER GULF MOISTURE WORKS OVER
THE REGION DUE TO PERSISTENT SOUTHERLY FLOW TONIGHT. DESPITE SOME
BETTER GULF MOISTURE MOVING IN OUT AHEAD OF THE COLD
FRONT...THUNDERSTORM AND SIGNIFICANT PRECIPITATION CHANCES WILL
REMAIN STRONGLY CAPPED BY WARM AIR ALOFT.
CAVANAUGH
&&
.UPDATE...
WITH LESS CLOUDS THIS MORNING THAN PREVIOUSLY FORECASTED...HAVE
BUMPED UP HIGHS A COUPLE OF DEGREES ACROSS MOST OF THE AREA. DID
NOT GO QUITE AS HIGH AS WHAT THE RAP WAS FORECASTING /MID-80S/.
OTHERWISE...MADE MINOR CHANGES TO THE OTHER HOURLY GRIDS TO
ACCOUNT FOR CHANGES.
HAMPSHIRE
&&
.PREV DISCUSSION... /ISSUED 353 AM CDT MON APR 22 2013/
TODAY WILL BE BREEZY AND WARMER WITH PLENTY OF SUNSHINE BUT
CHANGES ARE ON THE WAY TOMORROW AS AN UNSEASONABLY STRONG COLD
FRONT MOVES THROUGH. WE CONTINUE TO FAVOR THE SLIGHTLY FASTER
FRONTAL TIMING OF NAM/WRF MODELS...WHICH SUGGEST THE FRONT WILL
REACH THE DFW METROPLEX AROUND 9-10 AM TUESDAY...WACO AROUND
NOON...AND PUSH OUT OF THE SE ZONES BY 4 PM. HIGH TEMPS TUESDAY
WILL OCCUR AHEAD OF THE FRONT...AND WILL BE VERY SENSITIVE TO
EXACT FRONTAL TIMING. TEMPS BEHIND THE FRONT WILL PLUNGE 15-25
DEGREES...AND EXPECT THE NW HALF OF THE CWA TO BE IN THE UPPER 40S
BY MID-LATE AFTERNOON TUESDAY WITH A BRISK NORTHERLY WIND MAKING
IT FEEL EVEN COLDER. THE AIRMASS ACROSS NORTH TEXAS WILL BE CAPPED
BY A STRONG TEMPERATURE INVERSION NEAR 750MB...AND THEREFORE DEEP
CONVECTION ALONG THE FRONT APPEARS UNLIKELY. HOWEVER...THE FRONT
WILL PLOW INTO A SATURATED COLUMN BENEATH THIS INVERSION...AND
RAPID MECHANICAL LIFTING WILL LIKELY SQUEEZE OUT A THIN LINE OF
SHOWERS ALONG THE FRONTAL BOUNDARY. WOULD EXPECT MOST LOCATIONS TO
SEE BRIEF LIGHT RAIN TOMORROW...BUT THE CHANCE OF MEASURABLE
RAINFALL IS LOW AND THEREFORE WILL KEEP POPS AT 20 PERCENT.
OTHERWISE SOME AREAS OF DRIZZLE MAY DEVELOP OVER NORTH TEXAS
BEHIND THE FRONT IN THE AFTERNOON HOURS.
COLD AIR ADVECTION WILL CONTINUE INTO TUESDAY NIGHT AND EXPECT
TEMPS TO FALL INTO THE MID-UPPER 30S ACROSS THE NORTHERN ZONES TO
MID-UPPER 40S IN THE SOUTH FOR LOWS. SOUTHWEST FLOW ALOFT WILL
PREVAIL IN THE WAKE OF THE FRONT WHICH WILL SET UP AN OVERRUNNING
TYPE PATTERN. A SHORTWAVE TROUGH WILL MOVE THROUGH CENTRAL/EAST
TEXAS TUESDAY NIGHT. ELEVATED MOISTURE/INSTABILITY ARE SUFFICIENT
FOR WIDELY SCATTERED ELEVATED SHOWERS AND A FEW STORMS WITH BEST
CHANCES OVER THE SOUTHEAST HALF OF THE AREA WITH THIS WAVE TUESDAY
NIGHT. MODEL GUIDANCE IS STRUGGLING WITH TRYING TO TIME A SECOND
SUBSEQUENT SHORTWAVE. THE ECMWF IS POINTING AT WEDNESDAY NIGHT AND
THE GFS SEEMS TO HINT AT THIS AS WELL BUT SHOWS LITTLE QPF. THE
NAM/CANADIAN ARE EARLIER AND MORE FOCUSED ON WEDNESDAY. WILL BRUSH
SOME LOW POPS INTO WEDNESDAY BUT HOLD OFF ON BRINGING THEM INTO
WEDNESDAY NIGHT UNTIL WE GET MORE MODEL CONSISTENCY. THERE MAY BE
ENOUGH INSTABILITY FOR ELEVATED THUNDERSTORMS WITH THIS SECOND
SHORTWAVE BUT HAVE KEPT IT WORDED AS JUST SHOWERS FOR NOW. TEMPS
WEDNESDAY WILL BE IMPACTED SIGNIFICANTLY BY ANY POST-FRONTAL
CLOUDS/RAIN. WITH NORTH WINDS PREVAILING INTO WEDNESDAY AND CLOUDS
LIKELY TO PERSIST ACROSS AT LEAST THE SOUTHERN ZONES...HAVE
UNDERCUT GUIDANCE AND PUT HIGHS ONLY IN THE 50S THERE. THE
NORTHERN ZONES HAVE A BETTER CHANCE AT SEEING SOME LATE APRIL SUN
AND THEREFORE HAVE FORECAST WARMER TEMPS IN THE LOW 60S THERE.
COLD ADVECTION SHOULD WANE WEDNESDAY NIGHT AS WINDS TURN TO THE
EAST BUT CLOUDS SHOULD KEEP TEMPS FROM FALLING AS COOL AS GUIDANCE
SUGGESTS. BY THURSDAY...WINDS WILL TURN AROUND TO THE SOUTH BUT
STILL THINK THAT CLOUDS WILL BE PREVALENT AND TEMPER THE WARM UP.
HAVE UNDERCUT HIGHS FOR THURSDAY AND JUST WENT MID-UPPER 60S.
THE NEXT UPPER LEVEL SYSTEM IS A CLOSED LOW IN THE SUBTROPICAL
PACIFIC THAT WILL MELD WITH AN UPPER TROUGH OVER THE CONTINENT AND
MOVE ACROSS THE SOUTHERN PLAINS FRIDAY AND SATURDAY. STILL NOT
GETTING GREAT AGREEMENT IN THE MODELS WITH THIS FEATURE AND THE
ECMWF REMAINS THE STRONGEST/SLOWEST WITH IT. THE CANADIAN/UKMET
ARE PRETTY WEAK WITH THE FEATURE AND SUGGEST LIMITED QPF. THE GFS
SEEMS TO OFFER A COMPROMISE. WILL KEEP THE LOW POPS SPREAD ACROSS
THE AREA FRIDAY AND END THEM FROM WEST TO EAST SATURDAY. THE
AIRMASS ACROSS NORTH TEXAS WILL REMAIN FAIRLY COOL AND NOT HAVE
MUCH TIME TO RECHARGE OR DESTABILIZE AHEAD OF THIS SYSTEM...AND
THEREFORE WE MAY BE TOO STABLE OR CAPPED FOR A SIGNIFICANT
CONVECTIVE EVENT. THE CAP WOULD BE THE WEAKEST ACROSS THE
NORTHERN ZONES NEARER TO THE BETTER UPPER FORCING AND THEREFORE
HAVE BUMPED UP POPS TO 30 PERCENT IN THE NORTHEAST FRIDAY NIGHT.
OTHERWISE...THE ECMWF IS THE ONLY MODEL SHOWING A COLD FRONT
BEHIND THIS SYSTEM ON SATURDAY...AND THEREFORE HAVE KEPT WINDS
SOUTHERLY WITH TEMPS NEAR NORMAL SUNDAY INTO MONDAY.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 80 62 65 39 61 / 0 5 20 20 20
WACO, TX 81 62 72 42 58 / 0 5 20 30 20
PARIS, TX 77 58 65 40 62 / 0 10 20 20 10
DENTON, TX 80 59 59 37 62 / 0 10 20 20 10
MCKINNEY, TX 78 61 64 38 62 / 0 10 20 20 10
DALLAS, TX 80 63 66 42 61 / 0 5 20 20 20
TERRELL, TX 79 60 69 41 61 / 0 5 20 20 20
CORSICANA, TX 81 62 74 44 59 / 0 5 20 30 20
TEMPLE, TX 81 62 74 43 58 / 0 5 20 30 20
MINERAL WELLS, TX 81 55 55 36 60 / 0 5 20 20 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
347 PM CDT MON APR 22 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 347 PM CDT MON APR 22 2013
POSITIVITY TILTED UPPER LEVEL TROUGH MOVING THROUGH WITH A FEW
EMBEDDED SHORTWAVES NOTED THAT WILL IMPACT THE REGION TONIGHT AND
TUESDAY...ONE ACROSS THE NORTHERN PLAINS...AND A SECOND ROTATING
THROUGH THE INTERMOUNTAIN WEST. AT THE SURFACE...MAIN AREA OF LOW
PRESSURE IS SITUATED IN SOUTHWESTERN KANSAS...WITH A SECONDARY LOW
DEVELOPING NEAR KANSAS CITY. A WARM FRONTAL BOUNDARY EXTENDS
NORTHEAST TO NEAR DES MONIES...LA CROSSE...AND WAUSAU. DEFORMATION
BANDING PRECIPITATION IS DEVELOPING ALONG AND NORTH OF THE
FRONT...LIFTING THROUGH THE AREA THIS AFTERNOON.
NEAR-TERM GUIDANCE AND MESO-MODEL SOLUTIONS IN GOOD AGREEMENT
SHOWING LOW PRESSURE RIDING ALONG THIS BOUNDARY TONIGHT...CENTERING
NEAR LA CROSSE BY 06Z. STRONG FRONTOGENETICAL FORCING ON THE
NORTHWEST SIDE WILL KEEP DEFORMATION BAND PRECIPITATION IN PLACE
ACROSS SOUTHERN MINNESOTA INTO PARTS OF WESTERN WISCONSIN.
BIGGEST FORECAST CONCERN REMAINS ON WHEN PRECIPITATION WILL
TRANSITION FROM RAIN TO A RAIN/SNOW MIX...THEN TO ALL SNOW...AND
WHAT SNOWFALL ACCUMULATIONS RESULT. 22.12Z PROBABILISTIC AND
DETERMINISTIC GUIDANCE DID NOT VARY TOO MUCH FROM PREVIOUS
RUNS...AND STILL POINT TO SOUTHERN INTO CENTRAL MINNESOTA...AND
THEN INTO NORTHWEST WISCONSIN WITH THE HIGHER THREAT OF
ACCUMULATING SNOW. LOCALLY...THE MOST CONCERN IS FOR EXTREME
NORTHWEST DODGE/WABASHA COUNTIES IN MINNESOTA...AND TAYLOR COUNTY
IN WISCONSIN WHERE 1 TO 2 INCHES ARE POSSIBLE. THIS CHANGE OVER IS
EXPECTED AROUND MIDNIGHT OR SO...SLOWLY WORKING EAST DURING THE
OVERNIGHT.
CROSS SECTIONS THROUGH SOUTHEAST MINNESOTA SHOW STRONG SLOPING
FRONTOGENETIC SIGNAL WITH NEGATIVE EPV ABOVE...SO CONVECTIVE ELEMENTS
ARE POSSIBLE. THIS WOULD ENHANCE PRECIPITATION RATES...AND ALLOW
DYNAMIC COOLING TO WIN OUT. END RESULT...THERE COULD BE QUICK
BURSTS OF SNOW IN THESE AREAS AND THIS WILL BE SOMETHING TO WATCH
CLOSELY TONIGHT. RIGHT NOW THE HIGHER THREAT IS JUST OFF TO THE
NORTHWEST.
SOUNDINGS SHOW THE ATMOSPHERE LOSES ICE SATURATION OVERNIGHT AS
SURFACE TEMPERATURES COOL TO NEAR FREEZING. COMBINED WITH A
RETREATING WARM NOSE AT 850 MB....THERE IS A BRIEF FREEZING RAIN
OR FREEZING DRIZZLE THREAT ACROSS PORTIONS OF SOUTHEAST MINNESOTA
INTO NORTH CENTRAL WISCONSIN. 22.09Z SREF PROBABILITIES DEPICT A
10 TO 30 PERCENT PROBABILITY AS WELL. HAVE INCREASED THIS SOME
FROM PREVIOUS FORECAST...AND A VERY MINOR GLAZE IS POSSIBLE.
FOR TUESDAY...THE SURFACE LOW IS EXPECTED TO LIFT INTO THE GREAT
LAKES AND THERE SHOULD BE A QUICK WEST TO EAST END TO PRECIPITATION
IN THE MORNING HOURS. PLAN ON BLUSTERY NORTHWEST WINDS 10 TO 20
MPH...WITH HIGHER GUSTS UP TO 30 MPH. SKIES WILL CLEAR DURING THE
AFTERNOON AS DRIER AIR WORKS IN ACROSS THE AREA ALONG WITH SURFACE
HIGH PRESSURE BUILDING IN. FINALLY...TEMPERATURES WILL BE NEARLY 20
DEGREES BELOW NORMAL..WITH LOWER 40S COMMON ACROSS THE AREA.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 347 PM CDT MON APR 22 2013
FOCUS IN THE LONG TERM IS ON A RATHER VIGOROUS NORTHERN STREAM
SHORTWAVE FOR WED/WED NIGHT...THEN LOOKING FORWARD TO THE
MUCH-ANTICIPATED FIRST SPRING WARM UP THAT IS POSSIBLE THIS WEEKEND.
FOR WEDNESDAY A POTENT SHORTWAVE TROUGH IS EXPECTED TO QUICKLY DIVE
OUT OF THE NORTHERN PLAINS IN THE AFTERNOON AND EVENING HOURS. THIS
SYSTEM IS CHARACTERIZED BY VERY STEEP LOW-LEVEL LAPSE RATES THANKS
TO AN ANOMALOUSLY COLD MID/UPPER LEVEL CORE. 500 MB STANDARDIZED
ANOMALIES OFF THE 22.00Z ECMWF VARY FROM 2 TO 2.5 SD BELOW NORMAL.
ALTHOUGH MOISTURE CONVERGENCE IS LACKING...THE MID/UPPER LEVEL
DYNAMICS LOOK TO BE SUFFICIENT ENOUGH TO WARRANT HIGHER
PRECIPITATION CHANCES. THERE REMAINS SOME TIMING DIFFERENCE BETWEEN
22.12 GUIDANCE...AND THE LATER ARRIVAL WOULD POINT TOWARD MORE A
RAIN/SNOW MIX. LOCATIONS NORTH OF I-94 COULD PICK UP A 1/2 INCH OF
SNOW LATE WEDNESDAY NIGHT AS COOLING CHANGES RAIN OVER TO WET SNOW.
THE LATE WEEK INTO THE UPCOMING WEEKEND FEATURES RETURN SOUTHWESTERLY
FLOW AS THE UPPER LEVEL FLOW RIDGING TAKES SHAPE. 850 MB
TEMPERATURES RISE FROM AROUND -5C ON THURSDAY...TO AS HIGH AS +10 TO
+14C BY SUNDAY. HIGHS FRIDAY/SATURDAY WILL RISE INTO THE 60S...WITH
LOW 70S POSSIBLE SUNDAY/MONDAY. DESPITE WARM TEMPERATURES...A
LINGERING BOUNDARY TO THE NORTH WARRANTS SLIGHT CHANCES NORTH OF
I-90 SATURDAY NIGHT INTO SUNDAY. THIS WILL BE WELCOME NEWS TO THOSE
WHO ARE LOOKING FORWARD TO SOME SPRING WEATHER...HOWEVER THIS COULD
POTENTIALLY CREATE HYDROLOGY ISSUES...SO SEE HYDROLOGY SECTION FOR
MORE DETAILS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1218 PM CDT MON APR 22 2013
SURFACE FRONT IS BISECTING THE AREA EXTENDING FROM ABOUT KMCW TO
KLSE TO KRRL. THE 22.15Z RAP ALONG WITH THE 22.12Z HRRR AND 22.06Z
HI-RES ARW AND NMM ALL SUGGEST THE EASTERN PART OF THE FRONT WILL
LIFT SLOWLY NORTH THROUGH THE AFTERNOON WHILE THE WESTERN PART
REMAINS NEARLY STATIONARY. THIS WOULD ALLOW THE FRONT TO LIFT
BACK THROUGH KLSE BRINGING IN THE WARM SECTOR WHILE KRST WOULD
STAY ON THE COOL SIDE OF THE FRONT. HAVE INDICATED THESE TRENDS
WITH THE WINDS COMING AROUND TO THE EAST/SOUTHEAST AT KLSE WITH
VFR CONDITIONS FOR THE MID TO LATE AFTERNOON. WITH KRST STAYING ON
THE COOL SIDE OF THE FRONT...EXPECTING IFR CONDITIONS FOR THE
REMAINDER OF THE AFTERNOON. THE NEXT SHORT WAVE TROUGH...CURRENTLY
OVER SOUTH DAKOTA AND NEBRASKA...WILL MOVE IN THIS EVENING WITH AN
INCREASE IN THE FORCING. AT THE SAME TIME...THE FRONTOGENESIS IN
THE 1000-700 MB LAYER IS EXPECTED TO BE STRONG ALONG THE FRONT
CAUSING A WIDESPREAD AREA OF RAIN TO DEVELOP AND MOVE ACROSS THE
REGION OVERNIGHT. ENOUGH COLD AIR IS EXPECTED TO COME IN AT KRST
FOR THE RAIN TO MIX WITH SNOW AROUND 06Z. THE NAM SOUNDINGS
SUGGEST THE POTENTIAL FOR ICE IN THE CLOUDS TO BE LOST AND THE
PRECIPITATION POSSIBLY BECOMING DRIZZLE OR FREEZING DRIZZLE BASED
ON TEMPERATURES. SOME POTENTIAL FOR A SHORT PERIOD OF FREEZING
DRIZZLE AND HAVE INCLUDED THIS FOR LATE TONIGHT BEFORE THE
PRECIPITATION ENDS AROUND 12Z. KLSE IS EXPECTED TO REMAIN WARM
ENOUGH FOR JUST RAIN AT THIS POINT BEFORE THE IT ENDS SHORTLY
AFTER 12Z.
&&
.HYDROLOGY...TONIGHT/TUESDAY
ISSUED AT 347 PM CDT MON APR 22 2013
THE TONIGHT/TUESDAY EVENT IS EXPECTED TO RESULT IN 0.5 TO UP 1.0
INCH OF LIQUID ACROSS PORTIONS OF SOUTHEAST MINNESOTA AND WESTERN
INTO CENTRAL WISCONSIN. SATURATED GROUND FROM THE RECENT
RAINFALL...ALONG WITH SNOWPACK REMAINING IN PLACE ACROSS CENTRAL
MINNESOTA INTO NORTH CENTRAL WISCONSIN WILL KEEP AN ELEVATED RISK
OF HYDROLOGY ISSUES. FORECAST RAINFALL AMOUNTS BRING THE
TREMPEALEAU RIVER AT DODGE POTENTIALLY ABOVE FLOOD STAGE LATER
THIS WEEK BUT GIVEN SOME UNCERTAINTY IN WHAT BASINS WILL EXPERIENCE
THE HIGHER AMOUNTS...AT THIS TIME A FLOOD WATCH WAS POSTED.
LOOKING AHEAD...THE POSSIBLE SIGNIFICANT WARM UP ACROSS THE UPPER
MIDWEST THIS WEEKEND INTO EARLY NEXT WEEK COULD LEAD TO RAPID
SNOWMELT ACROSS CENTRAL MINNESOTA AND THE NORTHERN HALF OF
WISCONSIN. THIS WOULD LEAD TO SIGNIFICANT RISES ON AREA
TRIBUTARIES SUCH AS THE BLACK AND TREMPEALEAU RIVER...AND
EVENTUALLY ON THE MAIN STEM OF THE MISSISSIPPI RIVER. CURRENT
FORECASTS SHOW 1 TO 2 FEET RISES ON THE MISSISSIPPI BY THIS
WEEKEND...ABOVE ACTION STAGE AT MANY SITES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 9 AM CDT
TUESDAY FOR WIZ017.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...ZT
LONG TERM...ZT
AVIATION...04
HYDROLOGY...ZT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1218 PM CDT MON APR 22 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 255 AM CDT MON APR 22 2013
SHOWERS CONTINUE TO TRACK ALONG A NORTHEAST-SOUTHWEST RUNNING COLD
FRONT...EXTENDING FROM NORTHEAST WI...ACROSS THE HEART OF THE
FORECAST AREA...AND THEN ACROSS SOUTHERN IA. THE FRONT MAKES VERY
SLOW PROGRESS TO THE EAST...ESSENTIALLY STAYING HUNG UP ACROSS THE
FORECAST AREA INTO TONIGHT. EXPECTING SOME DECREASE IN AREAL EXTENT
OF THE SHOWERS THIS MORNING AS THE LOW LEVEL MOISTURE TRANSPORT
WEAKENS. THESE SHOULD START TO BECOME MORE NUMEROUS THIS AFTERNOON
AS THE FRONTOGENETIC FORCING INCREASES...MOSTLY ALONG AND NORTH OF
THE SFC BOUNDARY...ACTING MORE AS A WARM FRONT NOW. BETTER CHANCES
IN THE NORTH.
TONIGHT...PRECIPITATION WILL CONTINUE TO EXPAND AS A SFC LOW MOVES
OUT OF THE PLAINS TO ACROSS THE FORECAST AREA BETWEEN 03-06Z. GOOD
AMOUNT OF LOW LEVEL WARM AIR ADVECTION...WITH SLOPING FRONTOGENETIC
FORCING INDICATED IN A NORTHWEST-SOUTHEAST X-SECTION. SOME UPPER
LEVEL PIECES OF SHORTWAVE ENERGY WILL BE ADDED TO THE FORCING
MIX...WITH A COUPLED UPPER LEVEL JET AS THE CHERRY ON TOP. THE BULK
OF THIS PRECIPITATION WILL FALL IN THE TRADITIONAL DEFORMATION
REGION NORTHWEST OF THE SFC LOW...SO WHERE THIS TRACKS WILL BE
PARAMOUNT TO REFINING THE HIGHER PCPN CHANCES...AND AMOUNTS. THERE
WILL STILL BE SOME SHOWER CHANCES ALONG THE SOUTHERN PART OF THE
BOUNDARY...THE COLD FRONT PORTION OF THE LOW PRESSURE SYSTEM. THIS
AREA COULD SEE A FEW ISOLATED THUNDERSTORMS WITH A BIT OF
INSTABILITY TO TAP INTO.
IN THE NORTHWEST/DEFORMATION REGION...TEMP PROFILES VIA X-SECTIONS
AND BUFKIT SOUNDINGS WOULD SUPPORT A RAIN/SNOW TO SNOW PCPN TYPE.
LOOKING AT SIGNIFICANT SNOW ACCUMULATIONS OVER CENTRAL MN INTO
NORTHWEST WI. LOCALLY...THE BEST CHANCES FOR SNOW ACCUMS WILL BE
NORTH OF HIGHWAY 29 IN NORTH CENTRAL WI WHERE 1 TO 4 INCHES COULD BE
ON THE GROUND FOR THE TUE MORNING COMMUTE. MOST OF THIS WILL BE ON
COLDER/GRASSY SFCS...BUT MOST ROADS WILL LIKELY HAVE SOME SNOW ON
THEM. WITH THIS IN MIND...WILL ISSUE A WINTER WEATHER ADVISORY FOR
LATE THIS EVENING THROUGH THE MORNING RUSH HOUR ON TUESDAY FOR
TAYLOR COUNTY.
.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 255 AM CDT MON APR 22 2013
22.00Z GFS AND NAM SOLUTIONS CONTINUE TO FAVOR A 500 MB SHORTWAVE
TROUGH DROPPING SOUTHEAST ACROSS THE NORTHERN PLAINS...TO ACROSS THE
UPPER MISSISSIPPI RIVER VALLEY BY 06Z THU. GOOD PUNCH OF MID/UPPER
LEVEL QG CONVERGENCE WITH THE FEATURE...ESPECIALLY IN THE 700-300 MB
LAYER. NOT MUCH LOW LEVEL THERMODYNAMICS NOR APPRECIABLE SOUTHERN
MOISTURE FETCH. STILL...ENOUGH FOR A GOOD/LIKELY SHOT FOR PCPN.
TIMING OF THE SHORTWAVE WOULD MAKE A RAIN...TO RAIN/SNOW...TO SNOW
TRANSITION ALSO LIKELY. COULD SEE MINOR SNOW ACCUMULATIONS ON
GRASSY/COLD SFCS. WINTER CERTAINLY ISN/T DONE WITH US QUITE YET.
THE UPPER LEVEL FLOW TURNS MORE ZONAL AND IS FAIRLY PROGRESSIVE
HEADING INTO THE WEEKEND. MOST BITS OF SHORTWAVE ENERGY ARE SHUNTED
NORTH OR SOUTH OF THE FORECAST AREA...BUT THE GFS AND EC DO SUGGEST
THAT A SHORTWAVE COULD SLIDE ACROSS NORTHERN PARTS OF THE REGION SAT
NIGHT/SUN. PCPN WOULD RESULT...BETTER IN THE NORTH...BUT ALSO ALONG
THE SYSTEM/S LEADING FRONT...WHICH COULD IMPACT US.
MORE SIGNIFICANTLY IS THE LIKELIHOOD THAT
SPRING...NORMAL...TEMPERATURES FINALLY MAKE AN APPEARANCE.
SOUTHERLY WINDS OUT AHEAD OF THE SAT NIGHT SYSTEM WILL PUSH TEMPS
UP...AND ITS LOOKING MORE AND MORE LIKELY THAT HIGHS WILL JUMP INTO
THE 60S FOR FRI/SAT/SUN. CAN/T RULE OUT A FEW 70S THIS WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1218 PM CDT MON APR 22 2013
SURFACE FRONT IS BISECTING THE AREA EXTENDING FROM ABOUT KMCW TO
KLSE TO KRRL. THE 22.15Z RAP ALONG WITH THE 22.12Z HRRR AND 22.06Z
HI-RES ARW AND NMM ALL SUGGEST THE EASTERN PART OF THE FRONT WILL
LIFT SLOWLY NORTH THROUGH THE AFTERNOON WHILE THE WESTERN PART
REMAINS NEARLY STATIONARY. THIS WOULD ALLOW THE FRONT TO LIFT
BACK THROUGH KLSE BRINGING IN THE WARM SECTOR WHILE KRST WOULD
STAY ON THE COOL SIDE OF THE FRONT. HAVE INDICATED THESE TRENDS
WITH THE WINDS COMING AROUND TO THE EAST/SOUTHEAST AT KLSE WITH
VFR CONDITIONS FOR THE MID TO LATE AFTERNOON. WITH KRST STAYING ON
THE COOL SIDE OF THE FRONT...EXPECTING IFR CONDITIONS FOR THE
REMAINDER OF THE AFTERNOON. THE NEXT SHORT WAVE TROUGH...CURRENTLY
OVER SOUTH DAKOTA AND NEBRASKA...WILL MOVE IN THIS EVENING WITH AN
INCREASE IN THE FORCING. AT THE SAME TIME...THE FRONTOGENESIS IN
THE 1000-700 MB LAYER IS EXPECTED TO BE STRONG ALONG THE FRONT
CAUSING A WIDESPREAD AREA OF RAIN TO DEVELOP AND MOVE ACROSS THE
REGION OVERNIGHT. ENOUGH COLD AIR IS EXPECTED TO COME IN AT KRST
FOR THE RAIN TO MIX WITH SNOW AROUND 06Z. THE NAM SOUNDINGS
SUGGEST THE POTENTIAL FOR ICE IN THE CLOUDS TO BE LOST AND THE
PRECIPITATION POSSIBLY BECOMING DRIZZLE OR FREEZING DRIZZLE BASED
ON TEMPERATURES. SOME POTENTIAL FOR A SHORT PERIOD OF FREEZING
DRIZZLE AND HAVE INCLUDED THIS FOR LATE TONIGHT BEFORE THE
PRECIPITATION ENDS AROUND 12Z. KLSE IS EXPECTED TO REMAIN WARM
ENOUGH FOR JUST RAIN AT THIS POINT BEFORE THE IT ENDS SHORTLY
AFTER 12Z.
&&
.HYDROLOGY...
ISSUED AT 255 AM CDT MON APR 22 2013
STILL LOOKING AT AN ADDITIONAL 1/3 TO 1 INCH OF LIQUID EQUIVALENT
PCPN TODAY AND TONIGHT...MORE ACROSS WESTERN/NORTHERN PARTS OF THE
FORECAST AREA. GROUNDS ARE SATURATED AND MUCH OF WHAT FALLS COULD GO
INTO RUNOFF INTO THE WATER WAYS. THIS WOULD LEAD TO WITHIN BANK
RISES...BUT ADDITIONAL FLOODING IS NOT ANTICIPATED. IF THE AMOUNTS
ARE HIGHER THAN EXPECTED...OR IT COMES DOWN IN A SHORTER PERIOD OF
TIME...THE FLOOD THREAT WOULD INCREASE. THE CURRENT FLOODING ON THE
BLACK RIVER WILL CONTINUE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 9 AM CDT
TUESDAY FOR WIZ017.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM....RIECK
LONG TERM.....RIECK
AVIATION...04
HYDROLOGY.....RIECK