Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 03/31/13
AREA FORECAST DISCUSSION
NWS TAUNTON MA
709 AM EDT FRI MAR 29 2013
.SYNOPSIS...
MILD AND MAINLY DRY WEATHER IS EXPECTED THROUGH THE FIRST PART OF
THE WEEKEND. A SERIES OF FRONTS WILL BRING SOME WET WEATHER SUNDAY
NIGHT INTO MONDAY...WITH COLDER WEATHER EXPECTED INTO THE MID PART
OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
7 AM UPDATE...
ONLY MINOR TWEAKS NEEDED TO THE FORECAST THIS MORNING. UPDATED
SKIES TOWARD LATEST RAP SOLUTION GIVEN IT IS HANDLING SOME MID
CLOUDS OVER SRN NEW HAMPSHIRE AND CLOUDS UPSTREAM ASSOCIATED WITH
A SHORTWAVE EXPECTED TO MOVE OVER THE AREA TODAY. STILL EXPECTING
ANOTHER ROUND OF DIURNALLY DRIVEN SHOWERS PARTICULARLY CENTRAL AND
EASTERN PORTIONS OF THE FORECAST AREA...SO HAVE ADJUSTED POPS
SOMEWHAT AS WELL. OTHERWISE...ASIDE FROM BRINGING TEMPS AND DWPTS
UP TO CURRENT TRENDS...OTHER PARAMETERS REMAIN ON TRACK.
PREVIOUS DISCUSSION...
A MIXTURE OF CLOUDS AND SUNSHINE THIS MORNING WILL PROBABLY GIVE WAY
TO MORE IN THE WAY OF CLOUDINESS DURING THE AFTERNOON. THIS A
RESULT OF A MID LEVEL SHORTWAVE APPROACHING FROM THE WEST AND 500 MB
TEMPS DROPPING BELOW -30C. THIS SHOULD RESULT IN ENOUGH INSTABILITY
FOR ISOLATED SHOWERS TO DEVELOP DURING THE AFTERNOON.
HOWEVER...AREAL COVERAGE OF ANY ACTIVITY THAT DEVELOPS SHOULD BE
LIMITED AND THE VAST MAJORITY OF THE DAY SHOULD BE DRY IN A GIVEN
LOCATION. THEREFORE...JUST WILL INCLUDE LOW POPS IN THE FORECAST.
AS FOR HIGH TEMPS...THE ATMOSPHERE SHOULD BE WELL MIXED WITH
NORTHWEST SURFACE WINDS. SO DESPITE 850 MB TEMPS AROUND -3C...HIGH
TEMPS SHOULD REACH WELL INTO THE 50S ACROSS MOST LOCATIONS. WEAK
GRADIENT MAY ALLOW FOR SEA BREEZES TO DEVELOP ALONG THE VERY
IMMEDIATE COAST...RESULTING LOCALLY COOLER TEMPS IN THIS REGION
DURING THE AFTERNOON.
&&
.SHORT TERM /SATURDAY/...
TONIGHT...
ISOLATED DIURNALLY DRIVEN SHOWERS SHOULD DISSIPATE DURING THE
EVENING HOURS. HOWEVER...CONSIDERABLE CLOUDINESS MAY LINGER WELL
INTO THE OVERNIGHT HOURS GIVEN COLD POOL ALOFT AND A FAIR AMOUNT OF
MID LEVEL MOISTURE. THEREFORE...THINK GUIDANCE NUMBERS MAY BE A BIT
TOO COOL AND LOW TEMPS WILL MAINLY BE IN THE UPPER 20S TO THE MIDDLE
30S IN MOST LOCALES.
SATURDAY...
A NICE START TO THE WEEKEND IS ON TAP FOR SOUTHERN NEW ENGLAND. THE
UPPER TROUGH BEGINS TO MOVE EAST OF THE REGION ALLOWING FOR RISING
HEIGHT FIELDS. THIS SHOULD YIELD MAINLY DRY WEATHER AND MORE
SUNSHINE THAN TODAY. HIGHS AGAIN SHOULD BE IN THE LOWER TO MIDDLE
50S ACROSS MOST LOCALES.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
* WARMER TEMPERATURES EXPECTED THROUGH THE WEEKEND
* SHOWERS EXPECTED AHEAD OF WARM FRONT SUN AND MON
* COOLER WEATHER MOVES BACK IN TUES AND WED
OVERVIEW AND MODEL PREFERENCES...
29/00Z MODEL GUIDANCE SUITE IS BEGINNING TO CONVERGE ON BROAD
SCALE PATTERN THROUGH MUCH OF THE LONG TERM. MAINLY IN THAT THEY
CONTINUE THE GREENLAND BLOCK THAT HAS BEEN IN PLACE FOR MUCH OF
THE LAST MONTH OR SO. THEREFORE THE CUTOFF LOW PRES ASSOCIATED
WITH THE EARLY WEEK OCCLUSION/COLD FRONTAL PASSAGE WILL STALL IN
THE NEWFOUNDLAND LABRADOR REGION...DRAWING A FAIR AMOUNT OF COLD
AIR INTO SRN NEW ENGLAND THROUGH NEXT WEEK. WILL CONTINUE TO ERR
TOWARD A GFS/ECMWF BLEND AS A BASELINE. THE ONLY CAVEAT WILL BE A
SECONDARY ARCTIC FROPA STALLING S OF THE REGION AND SECONDARY
SHORTWAVE AND SFC LOW WHICH WILL PASS ALONG IT ON TUE. LATEST GFS
IS MORE SUPPRESSED...LEANING CLOSER TO ITS ENSEMBLE MEAN...WHILE
ECMWF HAS ALWAYS BEEN AB IT MORE SUPPRESSED. THERE IS STILL THE
SLIGHT THREAT FOR SOME LIGHT PRECIP /WHAT WOULD LIKELY BE SNOW/
ALONG THE S COAST WITH THIS WAVE...SO WILL MAINTAIN AT LEAST
SLIGHT CHANCE POPS /CLOSER TO THE ECWMF SOLUTION/ ON TUE.
DETAILS...
SAT NIGHT INTO SUN...
UPPER LVL RIDGE AND SFC HIGH PRES CREST OVER THE REGION AND
BEGINS TO SLIDE E. THIS ALLOWS FOR WARM ADVECTION UNDER RETURN
FLOW INTO SUN. THEREFORE...WARM TEMPS /POSSIBLY APPROACHING 60/
ARE LIKELY DISPUTE INCREASING CLOUDS IN ADVANCE OF OCCLUDED
FRONT. MUCH OF THE DAY REMAINS DRY ALTHOUGH AREAS NEAR AND W OF
THE CT VALLEY MAY BEGIN TO SEE SOME RAIN BY LATE AFTERNOON AND
EVENING.
SUN NIGHT AND MON...
MODELS STILL SHOWING DECENT OCCLUSION PUSHING THROUGH THE AREA AS
LOW PRES PASSES WELL N OF THE ST LAWRENCE VALLEY. DECENT MOISTURE
AND LIFT SUPPORT WIDESPREAD QPF VALUES AROUND A HALF INCH ALTHOUGH
WITH PWAT VALUES CLOSER TO 0.75-1.0 INCHES...A FEW LOCALLY HIGHER
AMOUNTS ARE POSSIBLE. GIVEN THE WARM START AND DECENT RIDGING THE
PRECIP WILL LIKELY REMAIN MOSTLY RAIN...ALTHOUGH THERMAL PROFILES
DO SUGGEST THAT HIGHER TERRAIN OF SRN MA AND NRN MA MAY CHANGE
OVER BRIEFLY LATE SUN NIGHT...WITH LITTLE ACCUMULATION.
STEERING FLOW SUGGESTS THIS FRONT IS A FAST MOVER AND PRECIP MAY
LIKELY DONE EVERYWHERE SAVE FOR MAYBE EXTREME N AND E LOCATIONS
NOT LONG AFTER 06Z. HOWEVER...AFTER A BRIEF LULL...A SECONDARY
ARCTIC FRONT IS EXPECTED TO PUSH THROUGH DURING THE
AFTERNOON...PRECIP FROM THIS TOO WILL LIKELY BE SHOWERY AND MOSTLY
RAIN TO START BUT A BRIEF CHANGE-OVER TO SNOW CANNOT BE RULED OUT
THANKS TO A VERY COLD AIRMASS BUILDING IN FROM THE W BEHIND THE
FRONT ESPECIALLY TOWARD THE OVERNIGHT HOURS. EXPECTING THAT THE
FRONT SHOULD BE OFFSHORE BY EARLY OVERNIGHT MON NIGHT.
TUE....
THE KEY HERE IS A MIX OF HOW QUICKLY SFC RIDGING MOVES IN AND
WHERE THE ARCTIC FRONT STALLS IN PROXIMITY TO SRN NEW ENGLAND. THE
ECMWF AND SOME ECENS/GEFS MEMBERS CONTINUE TO KEEP THE BAROCLINIC
ZONE FROM THE DELMARVA TO ABOUT THE BENCHMARK...WHILE THE GFS AND
A FEW ENSEMBLE MEMBERS ARE FURTHER S. WHEN A SECONDARY WAVE MOVES
THROUGH A WEAK LOW PRES IS EXPECTED TO MOVE ALONG THIS WAVE. THE
CLOSER PASS /ECMWF/ WOULD SUGGEST SOME PRECIP /LIKELY MOSTLY
SNOW...ALTHOUGH SOME RAIN COULD STILL MIX IN GIVEN THE EARLY APRIL
SUN ANGLE/ ESPECIALLY S OF THE MA PIKE WHILE THE GFS IS DRY. WILL
STILL AT LEAST HAVE POPS BECAUSE THE POTENTIAL IS THERE GIVEN THE
UPSTREAM BLOCK...BUT WILL NEED TO MONITOR THE SHORTWAVE ONCE IT
BECOMES BETTER SAMPLED.
WED INTO FRI...
UPPER LVL CUTOFF HOLDS NEAR LABRADOR-NEWFOUNDLAND ALLOWING FOR A
DRAW OF SEASONABLY COLD AIR INTO THE REGION AS STRONG HIGH PRES
BUILDS OVER FROM THE W. LIKELY SEE MOSTLY DRY CONDITIONS WITH
TEMPERATURES GENERALLY BELOW NORMAL FOR EARLY APRIL.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...HIGH CONFIDENCE THROUGH SATURDAY AFTERNOON.
VFR CONDITIONS DOMINATE MUCH OF THE DAY WITH SOME EVEN WITH SOME
LOWER STRATO-CU EXPECTED TO BUILD IN THROUGH THE DAY. CAN/T RULE
OUT SOME ISOLATED MVFR CIGS/VSBYS ASSOCIATED WITH SOME DIURNALLY
DRIVEN SHOWERS PARTICULARLY DURING THE AFTERNOON HOURS.
KBOS TAF...HIGH CONFIDENCE IN VFR BUT LOWER CONFIDENCE IN WIND
DIRECTION. MAIN CONCERN IS THE POTENTIAL FOR A WEAK SEABREEZE
DEVELOPMENT DURING THE AFTERNOON. WILL CARRY IT IN THE TAF DUE TO
POTENTIAL...BUT SHOULD WINDS NEVER QUITE DIMINISH BELOW 10 KT MAY
BE VERY LOW POTENTIAL IN SEA BREEZE COMING ONSHORE. WILL NEED TO
KEEP AN EYE ON WINDS THROUGH THE DAY.
KBDL TAF...HIGH CONFIDENCE IN TAF.
OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...
SAT NIGHT INTO EARLY SUN AFTERNOON...HIGH CONFIDENCE.
VFR. LIGHT AND VRB WINDS BECOME MORE SW INTO SUN.
LATE DAY SUN INTO MON...MODERATE CONFIDENCE.
VFR GIVES WAY TO MIX OF MVFR AND POTENTIALLY IFR IN RAIN. BULK OF
RAIN OCCURS EVENING AND EARLY OVERNIGHT SUN NIGHT WITH A BREAK
EARLY MON. POSSIBLE MVFR AGAIN WITH COLD FRONT DURING MON
AFTERNOON.
TUESDAY...MODERATE TO HIGH CONFIDENCE.
MAINLY VFR.
&&
.MARINE...
HIGH CONFIDENCE THROUGH SATURDAY AFTERNOON. WEAK PRESSURE GRADIENT
WILL KEEP WINDS/SEAS BELOW SCA THRESHOLDS THROUGH THAT TIME.
OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...
SAT NIGHT INTO EARLY SUN...HIGH CONFIDENCE.
WINDS AND SEAS REMAIN BELOW SMALL CRAFT THRESHOLDS THROUGH THE
PERIOD.
SUN NIGHT THROUGH TUE...MODERATE CONFIDENCE.
A SERIES OF FRONTS CROSS THE WATERS SUN NIGHT AND MON. THIS WILL
ALLOW WINDS TO APPROACH 25 KT AT TIMES PARTICULARLY ON THE OUTER
WATERS. SEAS ALSO GRADUALLY BUILD TO 5-8 FT ON OUTER WATERS WHICH
WILL LIKELY LINGER INTO TUE. SMALL CRAFT ADVISORIES ARE LIKELY
NEEDED THROUGH THE PERIOD.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...FRANK/DOODY
NEAR TERM...FRANK/DOODY
SHORT TERM...FRANK
LONG TERM...DOODY
AVIATION...FRANK/DOODY
MARINE...FRANK/DOODY
AREA FORECAST DISCUSSION...CORRECTED
NWS TAMPA BAY RUSKIN FL
320 AM EDT FRI MAR 29 2013
.SYNOPSIS...
07Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A GENERALLY BENIGN UPPER
LEVEL PATTERN ACROSS THE CONUS THIS MORNING. NORTHERN STREAM FLOW
FORMS A BROAD LONGWAVE RIDGE OVER THE INTER-MOUNTAIN WEST AND
CENTRAL PLAINS BEFORE SLIPPING BACK TO THE SOUTHEAST INTO A BROAD
TROUGH NOW EXITING INTO THE WESTERN ATLANTIC. 29/00Z KTBW SOUNDING
PROFILE CONTINUED TO SHOW A DRY COLUMN THROUGH THE EXTENT OF THE
TROP WITH A PW VALUE OF ONLY AROUND 0.3". WITH LITTLE MOISTURE AND
ESSENTIALLY NO SYNOPTIC SUPPORT FOR LIFT...SKIES ARE MOSTLY CLEAR
OVER THE REGION THIS MORNING.
AT THE SURFACE...HIGH PRESSURE IS RIDGING DOWN OVER THE PENINSULA
FROM THE SOUTHERN/CENTRAL APPALACHIANS. ONCE AGAIN THE LIGHT
GRADIENT...AND DRY ATMOSPHERE ARE ALLOWING TEMPERATURES TO BECOME
QUITE COOL FOR LATE MARCH DUE TO THE GOOD RADIATIONAL COOLING SETUP.
DUE TO CURRENTLY SLIGHTLY HIGHER DEWPOINTS COMPARED TO PREVIOUS
NIGHTS...NOT ANTICIPATING LOW TEMPERATURES TO DROP DOWN AS LOW AS
WAS SEEN THE PAST COUPLE NIGHTS. HOWEVER...A FEW NORMALLY COLDER
LOCATIONS OVER THE INTERIOR NATURE COAST AND ALSO DOWN ACROSS DE
SOTO...HARDEE... AND HIGHLANDS COUNTIES MAY BRIEFLY DIP INTO THE
MIDDLE 30S TOWARD SUNRISE WITH A THREAT FOR SOME PATCHY FROST.
&&
.SHORT TERM (TODAY THROUGH SUNDAY)...
TODAY/TONIGHT...A PLEASANT AND QUIET DAY ON TAP IN TERMS OF SENSIBLE
WEATHER. SURFACE HIGH PRESSURE WILL HOLD IN CONTROL OF THE REGION
UNDER A DEEP LAYER WEST TO NORTHWEST FLOW REGIME. THE LIGHT GRADIENT
WILL NOT BE IDEAL FOR MIXING...HOWEVER ABUNDANT SUNSHINE WOULD HELP
TEMPERATURES RISE INTO THE LOW/MID 70S NORTH OF I-4 AND MID/UPPER
70S SOUTH. SHOULD SEE JUST ENOUGH TERRESTRIAL WARMING TO FORCE A
FEEBLE SEA-BREEZE NEAR THE COAST THIS AFTERNOON...WHICH WILL HELP
KEEP THINGS A BIT COOLER AT THE BEACHES. LOW TEMPERATURES TONIGHT
WILL CONTINUE THE SLOW WARMING TREND...BUT STILL BE QUITE A BIT
BELOW AVERAGE FOR MANY LOCATIONS. LOOKS AS THROUGH TEMPS WILL STAY
WARM ENOUGH TO PREVENT ANY FROST CONCERNS...WITH THE COLDEST SPOTS
ACROSS THE NATURE COAST AND INTERIOR CENTRAL COUNTIES DROPPING DOWN
TO AROUND 40. ELSEWHERE WIDESPREAD MID/UPPER 40S LOOK COMMON AWAY
FROM THE WARMER SUNCOAST BEACHES.
SATURDAY/SATURDAY NIGHT...THE WARMING TREND CONTINUES! SURFACE HIGH
PRESSURE WILL SLIP OFF THE SE CONUS COAST...BUT CONTINUE TO RIDGE
BACK ACROSS THE CENTRAL FL PENINSULA. SLIGHTLY BETTER MIXING AND
MODIFIED LOW LEVEL AIRMASS SHOULD ALLOW AFTERNOON TEMPS TO REACH
WELL UP INTO THE 70S NORTH AND INTO THE LOWER 80S SOUTH AWAY FROM
THE BEACHES. THE BETTER WARMING SHOULD CERTAINLY HELP TO FORCE
SEA-BREEZE CIRCULATIONS SATURDAY AFTERNOON AND KEEP THE BEACHES
COOLER. THE SEA-BREEZES WILL HAVE MORE POTENTIAL TO MOVE INLAND
NORTH OF TAMPA BAY WHERE THE GRADIENT FLOW ON THE NORTH SIDE OF THE
RIDGE AXIS WILL AID IN THE EASTWARD EXPANSION OF THE CIRCULATION.
THE COOLEST SHELF WATERS ARE STILL FOUND OFF THE NATURE COAST...AND
WITH THIS IN MIND...HAVE TEMPERATURES DROPPING BACK DOWN TOWARD THE
UPPER 60S/LOW 70S NEAR THE COAST TO THE NORTH OF TAMPA BAY DURING
THE SECOND HALF OF THE AFTERNOON. PLENTY OF SUNSHINE IS LIKELY TO
START THE DAY...HOWEVER DURING THE MIDDLE TO LATER PORTION OF THE
AFTERNOON WOULD EXPECT A SLOW INCREASE IN MID/HIGH LEVEL CLOUDS
TO FILTER THE SUN IN RESPONSE TO THE APPROACH OF A WEAK IMPULSE.
SATURDAY NIGHT LOOKS TO BE DRY AND SEASONABLY COOL. COLDEST SPOTS
WILL ONLY DROP INTO THE UPPER 40S WITH MOST LOCATIONS STAYING ABOVE
50. THESE NUMBERS ARE CLOSE TO THE MOS CONSENSUS...HOWEVER COULD SEE
LOW TEMPS BEING EVEN WARMER...ESPECIALLY ACROSS THE NATURE COAST.
LATEST GFS/NAM CROSS SECTIONS BOTH SHOWING A BRIEF BY DECENT SWATH
OF MID/HIGH LEVEL MOISTURE AND SYNOPTIC LIFT ASSOCIATED WITH THE
PASSAGE OF THE PRE-MENTIONED IMPULSE. ALL THE DYNAMICS AND MOISTURE
ARE PRETTY HIGH...SO NOT ANTICIPATING ANY PRECIP POTENTIAL.
HOWEVER...IF SKIES DO END UP MOSTLY CLOUDY...THEN TEMPS SHOULD HAVE
A MORE DIFFICULT TIME FALLING FOR THE MAJORITY OF THE NIGHT.
SUNDAY...INITIAL IMPULSE QUICKLY PULLS EAST OF THE AREA DURING THE
MORNING. LOOKING WELL TO OUR NORTH...AN AMPLIFYING UPPER TROUGH
WILL HELP PUSH A WEAK COLD FRONT INTO THE SOUTHEASTERN CONUS DURING
THE DAY. THIS FRONT LOOKS TO STALL NORTH OF I-10 AND NEVER GET DOWN
THIS FAR DURING THE UPCOMING WEEKEND. NOT OUT OF THE QUESTION TO SEE
A BRIEF SHOWER OR TWO ACROSS LEVY/CITRUS COUNTIES ON SUNDAY...
HOWEVER THE BETTER LOW LEVEL FOCUS FOR LIFT ASSOCIATED WITH THE FRONT
IS CURRENTLY PROGGED TO STAY NORTH OF OUR ZONES. OF NOTE...THE
CONVECTIVE PARAMETRIZATION SCHEMES FROM THE GFS AND SOME SREF
MEMBERS ARE KICKING OFF OVER THE PENINSULA (SOUTH OF I-4) DURING
SUNDAY AFTERNOON. AGAIN...NOT OUT OF THE QUESTION TO SEE A BRIEF
SHOWER...HOWEVER...SURFACE DEWPOINTS IN THE 50S ARGUE AGAINST ANY
INSTABILITY THAT WOULD CURRENTLY WARRANT SHOWER MENTION IN THE
FORECAST. WILL KEEP POPS AT SILENT 10%. TEMPERATURES WILL CONTINUE
TO CLIMB ANOTHER COUPLE OF DEGREES FROM HIGHS ON SATURDAY.
&&
.LONG TERM (SUNDAY NIGHT THROUGH NEXT THURSDAY)...
HE PERIOD BEGINS WITH AN UPPER TROUGH JUST NORTH OF THE UPPER GREAT
LAKES WITH NEARLY ZONAL FLOW ALOFT THE GULF REGION...A FRONTAL
BOUNDARY STRETCHED ALONG THE GULF COAST/SE STATES...AND ATLANTIC
HIGH PRESSURE RIDGING WEST ACROSS FL TO THE GULF. THROUGH ABOUT
MID-WEEK THE UPPER TROUGH SAGS SOUTHWARD SOME AS IT TRACKS ALONG THE
GREAT LAKES...WITH THE FRONTAL BOUNDARY SHIFTING INTO NORTHERN GULF
WATERS AND THE NORTHERN HALF OF FL AS THE SURFACE RIDGE MOVES EAST
AND SOUTH. BY MID-WEEK THE UPPER TROUGH LIFTS NORTHEAST AS A SHORT
WAVE TROUGH MOVES FROM THE ROCKIES INTO THE SOUTHERN PLAINS THEN
EAST TO THE CENTRAL GULF COAST. THIS FORMS A SURFACE TROUGH/LOW
INITIALLY OVER THE WEST OR SOUTHWEST GULF THAT MOVES UP TO THE
NORTH-CENTRAL OR NORTHEAST GULF BY THE END OF THE PERIOD...WITH THE
BOUNDARY ACROSS THE STATE MOVING NORTH AS A WARM FRONT.
A SLIGHT CHANCE OF SHOWERS WILL ONLY REACH THE NORTHERN CWA MON AND
TUE BUT THEN SPREAD SOUTHWARD ACROSS THE REST OF THE CWA WED AND
THU...INCREASING TO LOW END CHANCE. TEMPERATURES WILL RUN ABOVE
NORMAL ALTHOUGH THEY WILL DECREASE SLIGHTLY AFTER MID-WEEK DUE TO AN
INCREASE IN CLOUDS AND RAIN CHANCES.
&&
.AVIATION...
VFR FOR THE NEXT 24 HOURS. LIGHT VARIABLE WINDS OVERNIGHT INCREASE
AND BECOME NE OR EAST IN THE MORNING THEN SHIFT TO NORTH OR NW IN
THE AFTERNOON.
&&
.MARINE...
HIGH PRESSURE WILL REMAIN IN CONTROL OF THE EASTERN GULF THROUGH
THE UPCOMING WEEKEND. WINDS AND SEAS ARE FORECAST TO REMAIN BELOW
HEADLINE CRITERIA WITH WINDS BECOME VARIABLE NEAR THE COAST EACH
AFTERNOON WITH THE DEVELOPMENT OF SEA-BREEZE CIRCULATIONS. A WEAK
FRONT WILL SETTLE INTO THE NORTHERN GULF AROUND TUESDAY OF NEXT WEEK
FOLLOWED BY WHAT LOOKS TO BE A PERIOD OF INCLEMENT WEATHER FOR THE
MIDDLE AND END OF THE WEEK.
&&
.FIRE WEATHER...
HIGH PRESSURE WILL REMAIN IN CONTROL OF THE REGION THE NEXT COUPLE
OF DAYS PROVIDING DRY CONDITIONS. WIDESPREAD DURATIONS OF CRITICALLY
LOW RELATIVE HUMIDITY ARE EXPECTED TODAY WITH MINIMUM VALUES
DROPPING INTO THE LOWER 20S FOR MANY LOCATIONS. RED FLAG WARNINGS
REMAIN IN EFFECT FOR PINELLAS...HIGHLANDS...POLK...SARASOTA...AND
LEE COUNTIES WHERE FORECASTED ERC VALUES ARE AT OR GREATER THAN 37.
ANOTHER DAY WITH WIDESPREAD CRITICALLY LOW RELATIVE HUMIDITY VALUES
EXPECTED FOR SATURDAY...HOWEVER THE MINIMUM VALUES SHOULD BE IN THE
MIDDLE AND UPPER 20S. A FIRE WEATHER WATCH HAS BEEN ISSUED FOR
POLK...HIGHLANDS...SARASOTA...AND LEE COUNTIES. PINELLAS AS BEEN
LEFT OUT OF THE WATCH AS CRITICAL DURATIONS OF LOW RELATIVE HUMIDITY
ARE NOT CURRENTLY EXPECTED ALONG THE COAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 73 53 75 60 / 0 0 0 10
FMY 79 54 81 59 / 0 0 0 10
GIF 76 48 80 55 / 0 0 0 10
SRQ 73 51 75 57 / 0 0 0 10
BKV 75 42 78 49 / 0 0 0 10
SPG 73 59 76 62 / 0 0 0 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...RED FLAG WARNING FROM 11 AM THIS MORNING TO 8 PM EDT THIS
EVENING FOR HIGHLANDS-LEE-PINELLAS-POLK-SARASOTA.
FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH
SATURDAY EVENING FOR HIGHLANDS-LEE-POLK-SARASOTA.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM/AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1220 PM CDT FRI MAR 29 2013
.DISCUSSION...
ISSUED 948 AM CDT FRI MAR 29 2013
HIGH PRESSURE AXIS CURRENTLY ANALYZED FROM WISCONSIN SOUTHEAST
INTO THE CAROLINAS. EARLIER WARM AIR ADVECTION SHOWERS HAVE
SHIFTED INTO THE OHIO VALLEY...ALTHOUGH SOME ALTOCUMULUS LINGERS
IN THE FORECAST AREA AND HAVE EVEN HAD A FEW SPRINKLES OUT OF IT
AROUND CHAMPAIGN. WHILE THE ALTOCUMULUS SHOULD DIMINISH WITH
TIME...CU-RULE OFF THE RAP MODEL SHOWS SOME DIURNAL CUMULUS
POTENTIAL FOR THIS AFTERNOON...WITH THE NET RESULT BEING PARTLY TO
MOSTLY SUNNY SKIES. MORNING COOPERATIVE OBSERVATIONS SHOWING ONLY
1 TO 3 INCHES OF SNOW LINGERING FROM NEAR LINCOLN SOUTHWEST TO
PITTSFIELD AND TRACE AMOUNTS EASTWARD...AND MUCH OF THIS SHOULD
DISAPPEAR TODAY AS HIGHS REACH INTO THE 50S.
HAVE SENT SOME UPDATED GRIDS TO ADJUST HOURLY TRENDS...BUT NO
CHANGES NEEDED TO THE ZONE FORECASTS AT THIS TIME.
GEELHART
&&
.AVIATION...
ISSUED 1220 PM CDT FRI MAR 29 2013
VFR CONDITIONS EXPECTED THE NEXT 24 HOURS. SOME SCATTERED TO
BROKEN CLOUDS AROUND 5000 FEET ARE EXPECTED THROUGH THE AFTERNOON.
WOULD NOT BE SURPRISED TO SEE THESE LINGER NEAR KSPI/KDEC FURTHER
INTO THE EVENING. SATURDAY MORNING...WILL BEGIN TO SEE A GENERAL
INCREASE IN CLOUDS FROM THE WEST...ALTHOUGH REMAINING VERY HIGH
THROUGH THE MORNING. WINDS THROUGH THIS EVENING WILL GENERALLY
REMAIN EASTERLY DUE TO AN AREA OF HIGH PRESSURE OVER THE
MIDWEST...THEN TREND TOWARD THE SOUTHEAST AND INCREASE ON SATURDAY
AHEAD OF A COLD FRONT APPROACHING FROM THE WEST.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 236 AM CDT FRI MAR 29 2013
SHORT TERM...TODAY THROUGH SATURDAY
SURFACE RIDGE AXIS EXTENDING FROM THE UPPER MS VALLEY SOUTHEAST
INTO THE OHIO VALLEY PROVIDED LIGHT WINDS OVERNIGHT. SCATTERED
SHOWERS WERE AFFECTING SOUTHERN MO IN THE VICINITY OF A SFC WARM
FRONT...WHILE ELEVATED WARM ADVECTION WAS PRODUCING SHOWERS INTO
SOUTHERN IL. OBSERVATIONAL TRENDS SUGGEST THIS ACTIVITY WILL
REMAIN SOUTH OF THE AREA THIS MORNING...BUT MAIN AFFECT FOR MOST
AREAS WILL BE AREAS OF AC AND MOSTLY CLOUDY SKIES THIS MORNING. AS
THE SYSTEM SINKS SOUTHEAST...A CLEARING TREND WORKS IN FROM THE
NORTH THIS AFTERNOON. WILL ADD A FEW DEGREES TO YESTERDAYS HIGHS
WITH MOST AREAS GETTING INTO THE LOW/MID 50S.
A COLD FRONT MOVING ACROSS THE STATE SATURDAY AFTERNOON/NIGHT
BRINGS SCATTERED SHOWERS WITH GENERALLY LIGHT QPF OF A QUARTER TO
LESS THAN A HALF INCH. 00Z NAM HAD TRENDED MUCH QUICKER WITH THIS
FEATURE BRINGING SHOWERS ALL THE WAY TO EASTERN IL BY SAT
AFTERNOON. FEEL THIS IS A BIT FAST AND HAVE BASED FORECAST ON
SREF/GFS BLEND WHICH BRINGS RAIN WEST OF THE IL RIVER BY MID TO
LATE AFTERNOON...THEN SHIFTS EAST ACROSS THE REMAINDER OF THE CWA
THROUGH EVENING. SOUTHERLY FLOW AHEAD OF THE FRONT WILL PRODUCE
THE WARMEST DAY OF THE MONTH FOR MANY AREAS WITH HIGHS IN THE
UPPER 50S.
LONG TERM...SUNDAY THROUGH THURSDAY
NOT MUCH OF A COOL PUSH BEHIND THE INITIAL FRONT AND READINGS
EXPECTED TO GET BACK UP INTO THE 50S SUNDAY ALONG WITH A FAIR
AMOUNT OF SUNSHINE. AN ARCTIC FRONT DIVING IN FROM THE NORTH
SUNDAY NIGHT SENDS TEMPERATURES CRASHING BACK WELL BELOW NORMAL.
FRONTOGENETIC FORCING ALONG/BEHIND THE BOUNDARY WILL WRING OUT
WHAT MOISTURE REMAINS AFTER THE PREVIOUS FRONTAL PASSAGE. THERMAL
PROFILES SUGGEST THE BULK OF THE PRECIP TO FALL AS SNOW AFTER A
BRIEF RAIN/SNOW MIX AT ONSET SUNDAY NIGHT. NAM MOST AGGRESSIVE AT
BRINGING ACCUMULATING SNOW...BUT GIVEN PROGRESSIVE NATURE OF FRONT
AND WARM GROUND FEEL ANY ACCUMULATIONS WILL BE MINOR. SNOW SHOULD
EXIT THE SOUTH/EAST MONDAY MORNING. BRISK NORTHERLY WINDS ON THE
EASTERN FLANK OF STRONG LATE SEASON 1035 MB ARCTIC HIGH BUILDING
INTO THE NORTHERN PLAINS...BRINGS STRONG COLD ADVECTION. 850 MB
TEMPS DIP AS LOW AS -12C ACROSS CENTRAL IL MONDAY AFTERNOON
THROUGH TUESDAY. THIS PRODUCES TEMPERATURES 20+ DEGREES BELOW
NORMAL WHICH MAY NOT BE TOO FAR FROM RECORD TERRITORY. IN CONTRAST
TO THE LAST ARCTIC AIR MASS...CYCLONIC FLOW IS DISPLACED MUCH
FARTHER NORTHEAST THIS TIME AROUND AND SHOULD RESULT IN MORE
SUNSHINE BY DAY AND CLEAR COLD NIGHTS. UNSEASONABLY COLD AND DRY
WEATHER CONTINUES THROUGH MID WEEK AS THE MODIFIED ARCTIC RIDGE
SETTLES OVERHEAD.
25
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
949 AM CDT FRI MAR 29 2013
.DISCUSSION...
ISSUED 948 AM CDT FRI MAR 29 2013
HIGH PRESSURE AXIS CURRENTLY ANALYZED FROM WISCONSIN SOUTHEAST
INTO THE CAROLINAS. EARLIER WARM AIR ADVECTION SHOWERS HAVE
SHIFTED INTO THE OHIO VALLEY...ALTHOUGH SOME ALTOCUMULUS LINGERS
IN THE FORECAST AREA AND HAVE EVEN HAD A FEW SPRINKLES OUT OF IT
AROUND CHAMPAIGN. WHILE THE ALTOCUMULUS SHOULD DIMINISH WITH
TIME...CU-RULE OFF THE RAP MODEL SHOWS SOME DIURNAL CUMULUS
POTENTIAL FOR THIS AFTERNOON...WITH THE NET RESULT BEING PARTLY TO
MOSTLY SUNNY SKIES. MORNING COOPERATIVE OBSERVATIONS SHOWING ONLY
1 TO 3 INCHES OF SNOW LINGERING FROM NEAR LINCOLN SOUTHWEST TO
PITTSFIELD AND TRACE AMOUNTS EASTWARD...AND MUCH OF THIS SHOULD
DISAPPEAR TODAY AS HIGHS REACH INTO THE 50S.
HAVE SENT SOME UPDATED GRIDS TO ADJUST HOURLY TRENDS...BUT NO
CHANGES NEEDED TO THE ZONE FORECASTS AT THIS TIME.
GEELHART
&&
.AVIATION...
ISSUED 615 AM CDT FRI MAR 29 2013
MAIN FORECAST CONCERN THIS PERIOD WILL BE COVERAGE OF LOW VFR
CIGS...ESP ACRS OUR SOUTHERN TAF (KSPI...KDEC AND KCMI) SITES
LATER THIS MORNING INTO THE AFTERNOON HOURS. NOT MANY CHANGES
PLANNED TO CURRENT SET OF TAFS AS MOISTURE FROM A DISTURBANCE
PASSING TO OUR SOUTH MAY KEEP THE LOWER VFR CIGS AROUND A BIT
LONGER ACROSS THE SOUTH BEFORE THEY PUSH OFF TO THE EAST AND
SOUTH BY LATE AFTN...LEAVING MAINLY VFR CONDITIONS FOR TNT.
WILL HAVE TO WATCH FOR THE POSSIBILITY OF SOME PATCHY FOG DEVELOP
LATE TONIGHT BUT AT THIS TIME IT APPEARS THAT PROBABILITY IS TOO
LOW TO INCLUDE IN THIS SET OF TAFS. WINDS WILL NOT BE A FACTOR
THRU TNT WITH SPEEDS OF LESS THAN 10 KTS...MOSTLY OUT OF AN
EASTERLY DIRECTION.
SMITH
&&
.PREV DISCUSSION...
ISSUED 236 AM CDT FRI MAR 29 2013
SHORT TERM...TODAY THROUGH SATURDAY
SURFACE RIDGE AXIS EXTENDING FROM THE UPPER MS VALLEY SOUTHEAST
INTO THE OHIO VALLEY PROVIDED LIGHT WINDS OVERNIGHT. SCATTERED
SHOWERS WERE AFFECTING SOUTHERN MO IN THE VICINITY OF A SFC WARM
FRONT...WHILE ELEVATED WARM ADVECTION WAS PRODUCING SHOWERS INTO
SOUTHERN IL. OBSERVATIONAL TRENDS SUGGEST THIS ACTIVITY WILL
REMAIN SOUTH OF THE AREA THIS MORNING...BUT MAIN AFFECT FOR MOST
AREAS WILL BE AREAS OF AC AND MOSTLY CLOUDY SKIES THIS MORNING. AS
THE SYSTEM SINKS SOUTHEAST...A CLEARING TREND WORKS IN FROM THE
NORTH THIS AFTERNOON. WILL ADD A FEW DEGREES TO YESTERDAYS HIGHS
WITH MOST AREAS GETTING INTO THE LOW/MID 50S.
A COLD FRONT MOVING ACROSS THE STATE SATURDAY AFTERNOON/NIGHT
BRINGS SCATTERED SHOWERS WITH GENERALLY LIGHT QPF OF A QUARTER TO
LESS THAN A HALF INCH. 00Z NAM HAD TRENDED MUCH QUICKER WITH THIS
FEATURE BRINGING SHOWERS ALL THE WAY TO EASTERN IL BY SAT
AFTERNOON. FEEL THIS IS A BIT FAST AND HAVE BASED FORECAST ON
SREF/GFS BLEND WHICH BRINGS RAIN WEST OF THE IL RIVER BY MID TO
LATE AFTERNOON...THEN SHIFTS EAST ACROSS THE REMAINDER OF THE CWA
THROUGH EVENING. SOUTHERLY FLOW AHEAD OF THE FRONT WILL PRODUCE
THE WARMEST DAY OF THE MONTH FOR MANY AREAS WITH HIGHS IN THE
UPPER 50S.
LONG TERM...SUNDAY THROUGH THURSDAY
NOT MUCH OF A COOL PUSH BEHIND THE INITIAL FRONT AND READINGS
EXPECTED TO GET BACK UP INTO THE 50S SUNDAY ALONG WITH A FAIR
AMOUNT OF SUNSHINE. AN ARCTIC FRONT DIVING IN FROM THE NORTH
SUNDAY NIGHT SENDS TEMPERATURES CRASHING BACK WELL BELOW NORMAL.
FRONTOGENETIC FORCING ALONG/BEHIND THE BOUNDARY WILL WRING OUT
WHAT MOISTURE REMAINS AFTER THE PREVIOUS FRONTAL PASSAGE. THERMAL
PROFILES SUGGEST THE BULK OF THE PRECIP TO FALL AS SNOW AFTER A
BRIEF RAIN/SNOW MIX AT ONSET SUNDAY NIGHT. NAM MOST AGGRESSIVE AT
BRINGING ACCUMULATING SNOW...BUT GIVEN PROGRESSIVE NATURE OF FRONT
AND WARM GROUND FEEL ANY ACCUMULATIONS WILL BE MINOR. SNOW SHOULD
EXIT THE SOUTH/EAST MONDAY MORNING. BRISK NORTHERLY WINDS ON THE
EASTERN FLANK OF STRONG LATE SEASON 1035 MB ARCTIC HIGH BUILDING
INTO THE NORTHERN PLAINS...BRINGS STRONG COLD ADVECTION. 850 MB
TEMPS DIP AS LOW AS -12C ACROSS CENTRAL IL MONDAY AFTERNOON
THROUGH TUESDAY. THIS PRODUCES TEMPERATURES 20+ DEGREES BELOW
NORMAL WHICH MAY NOT BE TOO FAR FROM RECORD TERRITORY. IN CONTRAST
TO THE LAST ARCTIC AIR MASS...CYCLONIC FLOW IS DISPLACED MUCH
FARTHER NORTHEAST THIS TIME AROUND AND SHOULD RESULT IN MORE
SUNSHINE BY DAY AND CLEAR COLD NIGHTS. UNSEASONABLY COLD AND DRY
WEATHER CONTINUES THROUGH MID WEEK AS THE MODIFIED ARCTIC RIDGE
SETTLES OVERHEAD.
25
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1227 PM EDT FRI MAR 29 2013
.UPDATE...
ISSUED AT 1227 PM EDT FRI MAR 29 2013
GRID UPDATE COMPLETED TO ADJUST FOR GENERALLY FASTER TRENDS IN
TEMP CLIMB...MUCH LOWER DEWPTS ACROSS THE NORTH AND SKY COVER.
SLOWLY DECREASING AREA OF MID CLOUDS THAT ORIGINATED OVER N
ILLINOIS WAS SLOWLY DRIFTING SE IMPACTING MAINLY ALONG AND SOUTH
OF US 30. WARMING CLOUD TOPS AND OVERALL APPEARANCE OF THE CLOUDS
WOULD SUGGEST A CONTINUATION OF MIXING OUT SHOULD OCCUR OVER THE
NEXT COUPLE OF HOURS...LEADING TO SUNNY TO MOSTLY SUNNY SKIES.
TEMPS CLIMBED FAIRLY RAPIDLY THIS MORNING BUT HAVE SINCE SHOWED
SIGNS OF SLOWING DOWN. IN AREAS WHERE THE SNOW PACK HAS BEEN GONE
MUCH DRIER SFC DEWPTS WERE IN PLACE WITH READINGS IN THE UPR TEENS
TO LOWER 20S VS UPR 20S TO AROUND 30 IN FAR S SECTIONS. DO EXPECT
THESE HIGHER DEWPTS TO MIX SOMEWHAT THROUGH THE DAY AS THE CLOUD
COVER LEAVES.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 523 AM EDT FRI MAR 29 2013
WEAK SHORT WAVE AND ASSOCIATED JET STREAK MOVING
ACROSS THE GREAT LAKES THIS MORNING. COUPLED WITH WEAK MID LEVEL
THETA E ADVECTION THESE FEATURES HAVE HELPED GENERATE AN AREA OF MID
LEVEL CLOUDS THIS MORNING JUST TO OUR WEST. RAP13 SEEMS TO HAVE BEST
HANDLE ON THIS MOISTURE WITH ITS 850-700MB LAYER RH. HRRR IS TRYING
TO CATCH UP BUT STILL DOES NOT APPEAR TO HAVE THE SCOPE SEEN ON
SATELLITE. SPECTRAL MODELS GENERALLY CLUELESS. SHORT WAVE WILL PASS
THROUGH OUR AREA DURING EARLY TO MID MORNING HOURS. RAP13 MOVES
HIGHER RH VALUES ACROSS WESTERN HALF OF OUR AREA THIS MORNING AND
GRADUALLY SINKS THIS AREA SOUTH WHILE MIXING ALSO HELPS TO ERODE
CLOUDS. HAVE INCREASED CLOUD COVER THIS MORNING SUBSTANTIALLY ACROSS
WESTERN AREAS USING SATELLITE TRENDS AND RAP AS GUIDANCE. GRADUALLY
DECREASED AMOUNT OF SKY COVER BY EARLY AFTERNOON SO SHOULD SEE A
PARTLY TO MOSTLY CLOUDY MORNING TRANSITIONING TO MOSTLY SUNNY THIS
AFTERNOON. EASTERN AREAS TO REMAIN FAR ENOUGH REMOVED PER
TRAJECTORIES TO KEEP MOSTLY SUNNY THROUGH THE DAY. RESULT OF THIS
MAY HELP KEEP TEMPS DOWN A FEW DEGREES WEST BUT EXPECT RAPID
INCREASE ONCE CLOUDS DEPART. OTHERWISE TEMPS WILL BE A FEW DEGREES
WARMER THAN THURSDAY OUTSIDE OF CLOUDS.
WARMER TEMPS ON SATURDAY AHEAD OF NEXT SHORT WAVE WITH HIGHS NEARING
60. INCREASING HIGH CLOUDS IN AFTERNOON MAY SLOW WARMING BUT IF
SKIES REMAIN CLEAR WOULD EXPECT SOME AREAS INTO 60S GIVEN MOS COOL
BIAS YESTERDAY WITH FULL SUN.
STRONG THETA E SURGE WITH MID LEVEL TROUGH APPROACHING SAT NIGHT
SHOULD LEAD TO RAIN SHOWERS. MODELS CONTINUE TO TREND FASTER WITH
NAM12 SHOWING PCPN DURING FIRST HALF OF NIGHT. USED COMPROMISE OF
SOLUTIONS FOR TIMING BUT LOOKS LIKE ALL AREAS WILL RECEIVE A NICE
RAINFALL OF ONE QUARTER TO ONE HALF INCH. ELEVATED THUNDER STILL NOT
OUT OF QUESTION BUT REMAINS LOW PROB EVENT SO NO INCLUSION JUST YET.
IF WE CAN GET SOME LIGHTNING WITH THIS RAIN RAPID GREEN UP WOULD BE
EXPECTED IN WAKE OF RAIN.
.LONG TERM...(SUNDAY THROUGH THURSDAY) ISSUED AT 523 AM EDT FRI MAR
29 2013
SUNDAY THROUGH THURSDAY...A WEAK UPPER LEVEL TROF WILL BE MOVING
ACROSS THE AREA SUNDAY...FOLLOWED BY A COLD FRONT SUNDAY NIGHT.
THERMAL PROFILES SUNDAY ARE BORDERLINE BETWEEN RAIN AND A RAIN/SNOW
MIX SUNDAY MORNING OVER NORTHERN AREAS...ESPECIALLY THE GFS. FOR NOW
LEFT JUST RAIN IN THE FCST GIVEN SFC TEMPERATURES MAINLY IN THE 40S
AND NAM 1000/850 MB THICKNESSES ALMOST EXCLUSIVELY ABOVE 1300
METERS. VERY CHILLY AIR WILL ONCE AGAIN SPREAD ACROSS THE AREA
SUNDAY NIGHT AND MONDAY. DELTA T VALUES SUPPORT SOME LAKE EFFECT
SNOW SHOWERS...HOWEVER...VERY LITTLE PRECONDITIONING IS EXPECTED. A
300 TO 310 FETCH WITH UPSTREAM DEW PTS IN THE SINGLE DIGITS MAY NOT
ALLOW MUCH MORE THAN LAKE EFFECT CLOUDS. OTHERWISE...ATTEMPTED TO
TREND TEMPERATURES DOWN MONDAY NIGHT THROUGH WEDNESDAY IN LINE WITH
THE GFS MEX MOS. 850 MB TEMPS TUESDAY MORNING NEAR -14C TUESDAY WILL
HELP KEEP HIGHS IN THE 30S...ESPECIALLY NEAR THE LAKE WITH LAKE
ENHANCED CLOUDS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1227 PM EDT FRI MAR 29 2013
A VFR MID DECK OF CLOUDS HAS BEEN PROGRESSIVELY MIXING
OUT...IMPACTING ONLY FT WAYNE AT THIS TIME. OVER THE NEXT COUPLE
OF HOURS CLEAR SKIES SHOULD SETTLE IN WITH CONTINUATION OF LIGHT
WINDS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...FISHER
SHORT TERM...LASHLEY
LONG TERM...SKIPPER
AVIATION...FISHER
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
623 AM EDT FRI MAR 29 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 523 AM EDT FRI MAR 29 2013
WEAK SHORT WAVE AND ASSOCIATED JET STREAK MOVING
ACROSS THE GREAT LAKES THIS MORNING. COUPLED WITH WEAK MID LEVEL
THETA E ADVECTION THESE FEATURES HAVE HELPED GENERATE AN AREA OF MID
LEVEL CLOUDS THIS MORNING JUST TO OUR WEST. RAP13 SEEMS TO HAVE BEST
HANDLE ON THIS MOISTURE WITH ITS 850-700MB LAYER RH. HRRR IS TRYING
TO CATCH UP BUT STILL DOES NOT APPEAR TO HAVE THE SCOPE SEEN ON
SATELLITE. SPECTRAL MODELS GENERALLY CLUELESS. SHORT WAVE WILL PASS
THROUGH OUR AREA DURING EARLY TO MID MORNING HOURS. RAP13 MOVES
HIGHER RH VALUES ACROSS WESTERN HALF OF OUR AREA THIS MORNING AND
GRADUALLY SINKS THIS AREA SOUTH WHILE MIXING ALSO HELPS TO ERODE
CLOUDS. HAVE INCREASED CLOUD COVER THIS MORNING SUBSTANTIALLY ACROSS
WESTERN AREAS USING SATELLITE TRENDS AND RAP AS GUIDANCE. GRADUALLY
DECREASED AMOUNT OF SKY COVER BY EARLY AFTERNOON SO SHOULD SEE A
PARTLY TO MOSTLY CLOUDY MORNING TRANSITIONING TO MOSTLY SUNNY THIS
AFTERNOON. EASTERN AREAS TO REMAIN FAR ENOUGH REMOVED PER
TRAJECTORIES TO KEEP MOSTLY SUNNY THROUGH THE DAY. RESULT OF THIS
MAY HELP KEEP TEMPS DOWN A FEW DEGREES WEST BUT EXPECT RAPID
INCREASE ONCE CLOUDS DEPART. OTHERWISE TEMPS WILL BE A FEW DEGREES
WARMER THAN THURSDAY OUTSIDE OF CLOUDS.
WARMER TEMPS ON SATURDAY AHEAD OF NEXT SHORT WAVE WITH HIGHS NEARING
60. INCREASING HIGH CLOUDS IN AFTERNOON MAY SLOW WARMING BUT IF
SKIES REMAIN CLEAR WOULD EXPECT SOME AREAS INTO 60S GIVEN MOS COOL
BIAS YESTERDAY WITH FULL SUN.
STRONG THETA E SURGE WITH MID LEVEL TROUGH APPROACHING SAT NIGHT
SHOULD LEAD TO RAIN SHOWERS. MODELS CONTINUE TO TREND FASTER WITH
NAM12 SHOWING PCPN DURING FIRST HALF OF NIGHT. USED COMPROMISE OF
SOLUTIONS FOR TIMING BUT LOOKS LIKE ALL AREAS WILL RECEIVE A NICE
RAINFALL OF ONE QUARTER TO ONE HALF INCH. ELEVATED THUNDER STILL NOT
OUT OF QUESTION BUT REMAINS LOW PROB EVENT SO NO INCLUSION JUST YET.
IF WE CAN GET SOME LIGHTNING WITH THIS RAIN RAPID GREEN UP WOULD BE
EXPECTED IN WAKE OF RAIN.
&&
.LONG TERM...(SUNDAY THROUGH THURSDAY) ISSUED AT 523 AM EDT FRI MAR
29 2013
SUNDAY THROUGH THURSDAY...A WEAK UPPER LEVEL TROF WILL BE MOVING
ACROSS THE AREA SUNDAY...FOLLOWED BY A COLD FRONT SUNDAY NIGHT.
THERMAL PROFILES SUNDAY ARE BORDERLINE BETWEEN RAIN AND A RAIN/SNOW
MIX SUNDAY MORNING OVER NORTHERN AREAS...ESPECIALLY THE GFS. FOR NOW
LEFT JUST RAIN IN THE FCST GIVEN SFC TEMPERATURES MAINLY IN THE 40S
AND NAM 1000/850 MB THICKNESSES ALMOST EXCLUSIVELY ABOVE 1300
METERS. VERY CHILLY AIR WILL ONCE AGAIN SPREAD ACROSS THE AREA
SUNDAY NIGHT AND MONDAY. DELTA T VALUES SUPPORT SOME LAKE EFFECT
SNOW SHOWERS...HOWEVER...VERY LITTLE PRECONDITIONING IS EXPECTED. A
300 TO 310 FETCH WITH UPSTREAM DEW PTS IN THE SINGLE DIGITS MAY NOT
ALLOW MUCH MORE THAN LAKE EFFECT CLOUDS. OTHERWISE...ATTEMPTED TO
TREND TEMPERATURES DOWN MONDAY NIGHT THROUGH WEDNESDAY IN LINE WITH
THE GFS MEX MOS. 850 MB TEMPS TUESDAY MORNING NEAR -14C TUESDAY WILL
HELP KEEP HIGHS IN THE 30S...ESPECIALLY NEAR THE LAKE WITH LAKE
ENHANCED CLOUDS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 622 AM EDT FRI MAR 29 2013
VFR CONDITIONS EXPECTED THROUGH THE PERIOD. SATELLITE
SHOWS AREA OF MID LEVEL CLOUDS THINNING WITH TIME AS THEY MOVE EAST
INTO DRIER AIR AND MID LEVEL JET MAX EXITS REGION. A FEW MORE HOURS
OF OCCASIONAL BKN080 POSSIBLE THIS MORNING BEFORE BECOMING SCT.
WINDS WILL REMAIN LIGHT THIS MORNING AND SHOULD STAY UNDER 10 KNOTS
TODAY. CLEAR SKIES AND LIGHT WINDS AGAIN TONIGHT.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...LASHLEY
LONG TERM...SKIPPER
AVIATION...LASHLEY
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
525 AM EDT FRI MAR 29 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 523 AM EDT FRI MAR 29 2013
WEAK SHORT WAVE AND ASSOCIATED JET STREAK MOVING
ACROSS THE GREAT LAKES THIS MORNING. COUPLED WITH WEAK MID LEVEL
THETA E ADVECTION THESE FEATURES HAVE HELPED GENERATE AN AREA OF MID
LEVEL CLOUDS THIS MORNING JUST TO OUR WEST. RAP13 SEEMS TO HAVE BEST
HANDLE ON THIS MOISTURE WITH ITS 850-700MB LAYER RH. HRRR IS TRYING
TO CATCH UP BUT STILL DOES NOT APPEAR TO HAVE THE SCOPE SEEN ON
SATELLITE. SPECTRAL MODELS GENERALLY CLUELESS. SHORT WAVE WILL PASS
THROUGH OUR AREA DURING EARLY TO MID MORNING HOURS. RAP13 MOVES
HIGHER RH VALUES ACROSS WESTERN HALF OF OUR AREA THIS MORNING AND
GRADUALLY SINKS THIS AREA SOUTH WHILE MIXING ALSO HELPS TO ERODE
CLOUDS. HAVE INCREASED CLOUD COVER THIS MORNING SUBSTANTIALLY ACROSS
WESTERN AREAS USING SATELLITE TRENDS AND RAP AS GUIDANCE. GRADUALLY
DECREASED AMOUNT OF SKY COVER BY EARLY AFTERNOON SO SHOULD SEE A
PARTLY TO MOSTLY CLOUDY MORNING TRANSITIONING TO MOSTLY SUNNY THIS
AFTERNOON. EASTERN AREAS TO REMAIN FAR ENOUGH REMOVED PER
TRAJECTORIES TO KEEP MOSTLY SUNNY THROUGH THE DAY. RESULT OF THIS
MAY HELP KEEP TEMPS DOWN A FEW DEGREES WEST BUT EXPECT RAPID
INCREASE ONCE CLOUDS DEPART. OTHERWISE TEMPS WILL BE A FEW DEGREES
WARMER THAN THURSDAY OUTSIDE OF CLOUDS.
WARMER TEMPS ON SATURDAY AHEAD OF NEXT SHORT WAVE WITH HIGHS NEARING
60. INCREASING HIGH CLOUDS IN AFTERNOON MAY SLOW WARMING BUT IF
SKIES REMAIN CLEAR WOULD EXPECT SOME AREAS INTO 60S GIVEN MOS COOL
BIAS YESTERDAY WITH FULL SUN.
STRONG THETA E SURGE WITH MID LEVEL TROUGH APPROACHING SAT NIGHT
SHOULD LEAD TO RAIN SHOWERS. MODELS CONTINUE TO TREND FASTER WITH
NAM12 SHOWING PCPN DURING FIRST HALF OF NIGHT. USED COMPROMISE OF
SOLUTIONS FOR TIMING BUT LOOKS LIKE ALL AREAS WILL RECEIVE A NICE
RAINFALL OF ONE QUARTER TO ONE HALF INCH. ELEVATED THUNDER STILL NOT
OUT OF QUESTION BUT REMAINS LOW PROB EVENT SO NO INCLUSION JUST YET.
IF WE CAN GET SOME LIGHTNING WITH THIS RAIN RAPID GREEN UP WOULD BE
EXPECTED IN WAKE OF RAIN.
&&
.LONG TERM...(SUNDAY THROUGH THURSDAY) ISSUED AT 523 AM EDT FRI MAR
29 2013
SUNDAY THROUGH THURSDAY...A WEAK UPPER LEVEL TROF WILL BE MOVING
ACROSS THE AREA SUNDAY...FOLLOWED BY A COLD FRONT SUNDAY NIGHT.
THERMAL PROFILES SUNDAY ARE BORDERLINE BETWEEN RAIN AND A RAIN/SNOW
MIX SUNDAY MORNING OVER NORTHERN AREAS...ESPECIALLY THE GFS. FOR NOW
LEFT JUST RAIN IN THE FCST GIVEN SFC TEMPERATURES MAINLY IN THE 40S
AND NAM 1000/850 MB THICKNESSES ALMOST EXCLUSIVELY ABOVE 1300
METERS. VERY CHILLY AIR WILL ONCE AGAIN SPREAD ACROSS THE AREA
SUNDAY NIGHT AND MONDAY. DELTA T VALUES SUPPORT SOME LAKE EFFECT
SNOW SHOWERS...HOWEVER...VERY LITTLE PRECONDITIONING IS EXPECTED. A
300 TO 310 FETCH WITH UPSTREAM DEW PTS IN THE SINGLE DIGITS MAY NOT
ALLOW MUCH MORE THAN LAKE EFFECT CLOUDS. OTHERWISE...ATTEMPTED TO
TREND TEMPERATURES DOWN MONDAY NIGHT THROUGH WEDNESDAY IN LINE WITH
THE GFS MEX MOS. 850 MB TEMPS TUESDAY MORNING NEAR -14C TUESDAY WILL
HELP KEEP HIGHS IN THE 30S...ESPECIALLY NEAR THE LAKE WITH LAKE
ENHANCED CLOUDS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY) ISSUED AT 123
AM EDT FRI MAR 29 2013
VFR CONDITIONS EXPECTED AT TAF SITES BUT SATELLITE SHOWS
A LARGE AREA OF MID LEVEL CLOUDS ACROSS IL ASSOCIATED WITH WEAK
SHORT WAVE AND MID LEVEL MOISTURE ADVECTION. RUC13 AND HRRR TO SOME
EXTENT ONLY MODELS PICKING UP ON THESE CLOUDS WITH RUC13 850-700MB
RH FIELDS HANDLING IT THE BEST. THIS GUIDANCE AND SATELLITE LOOPS
SUPPPORT A SOUTHEAST MOVEMENT AND EXPECT THESE CLOUDS INTO KSBN IN
NEXT FEW HOURS AND KFWA TOWARD DAYBREAK. SOUNDINGS AND CROSS
SECTIONS SUGGEST CLOUDS TO LINGER THROUGH MID TO LATE MORNING BEFORE
MIXING AND MOVING SOUTH. OTHERWISE LIGHT AND VARIABLE WINDS
GENERALLY UNDER 10 KNOTS THROUGH THE PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...LASHLEY
LONG TERM...SKIPPER
AVIATION...LASHLEY
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
141 AM EDT FRI MAR 29 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 327 PM EDT THU MAR 28 2013
NO SENSIBLE WEATHER CONCERNS THROUGH THE PERIOD WITH
SFC RIDGE AXIS...CURRENTLY LOCATED FROM THE ARROWHEAD OF MN INTO
CENTRAL TENNESSEE...SET TO DRIFT SLOWLY EAST. EVEN ON THE "COLD"
SIDE OF THE RIDGE...TEMPS HAVE REBOUNDED NICELY WITH MOST LOCATIONS
IN THE MID 40S. SNOW PACK STILL EXISTS IN THE FAR SOUTHERN
COUNTIES...HAMPERING THE WARM UP SLIGHTLY. HOWEVER...INCREASING LATE
MARCH SUN ANGLE HELPING OFFSET THE USUAL COLD CONTRIBUTION WITH MOST
SITES NOW PUSHING 40 AND SNOW PACK DWINDLING EACH HOUR.
GENERALLY CLEAR SKIES WILL PREVAIL WITH OVERNIGHT LOWS VERY SIMILAR
TO LAST NIGHT IN THE MID TO UPPER 20S. TEMPS WILL REBOUND ONCE AGAIN
ON FRIDAY...WITH SOUNDING INDICATE MIXING THROUGH TO AT LEAST 900
MB. AFTERNOON HIGHS WILL BE AT LEAST AS HIGH...IF NOT A FEW DEGREES
WARMER FRI AFTERNOON WITH MOST LOCATIONS IN THE UPR 40S TO AROUND
50.
&&
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 327 PM EDT THU MAR 28 2013
UPR LOW OVER NW TERRITORIES THIS AFTN WILL STRENGTHEN AND DIG SE TO
ONTARIO OVER THE WEEKEND AS JET STREAK OVER THE GULF OF ALASKA
PROPAGATES EAST INTO BASE OF THE TROF. LEAD SHRTWV TO S-SE OF UPR
LOW WILL MOVE ACROSS THE GRTLKS SAT NGT/SUNDAY. LOW LEVEL WAA AND
LINGERING DRY AIRMASS SHOULD ALLOW FOR ABOVE NORMAL TEMPS AHEAD OF
THIS SYSTEM SAT. NAM APPEARS TO BE SUFFERING FROM LOW LEVEL COOL
BIAS LATELY THUS LEANED TOWARD WARMER GFS/MAV GUIDANCE FOR HIGHS
SAT FCST IN THE M-U50S. STRONG/DEEP UVM... LOW LEVEL THETA-E
ADVECTION... AND WK INSTABILITY EXPECTED TO ACCOMPANY SHRTWV/CDFNT
SAT NGT AS IT MOVES INTO THE CWA... THUS TRENDED POPS/QPF UP FOR
THIS PERIOD... SOME POTENTIAL FOR ELEVATED TSTMS REACHING AS FAR
NORTH AS OUR CWA... BUT HELD OFF ADDING TO FCST ATTM. FRONTAL
BOUNDARY MOVG THROUGH ERN PORTION OF THE CWA SUNDAY MORNING WILL
LIKELY RESULT IN SHOWERS CONTG THERE... WITH JUST A CHC FARTHER
WEST. SHOULD BE A LITTLE COOLER SUNDAY BUT MAIN BLAST OF COLD AIR
EXPECTED TO MOVE INTO THE AREA SUNDAY NIGHT. ALONG WITH THE
SECONDARY CDFNT... SERIES OF MID LEVEL SHRTWV`S ROTATING AROUND
ONTARIO LOW WILL MOVE THROUGH THE GRTLKS SUNDAY
NIGHT/MONDAY...PSBLY ACCOMPANIED BY RAIN/SNOW SHOWERS. STRONG
CANADIAN SFC HIGH EXPECTED TO MOVE SE ACROSS THE PLAINS AND INTO
GRTLKS/OH VALLEY TUE-WED RESULTING IN DRY PERIOD. UNSEASONABLY
COLD CONDITIONS EXPECTED WITH HIGHS 35-40 MON-TUE. TEMPS SHOULD
WARM INTO THE 40S WED AS AIRMASS MODIFIES AND BACK TO NEAR NORMAL
BY THU AS WAA ON BACKSIDE OF THE RIDGE AND AHEAD OF A WK CDFNT
OVERSPREADS THE CWA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 134 AM EDT FRI MAR 29 2013
VFR CONDITIONS EXPECTED AT TAF SITES BUT SATELLITE SHOWS A LARGE
AREA OF MID LEVEL CLOUDS ACROSS IL ASSOCIATED WITH WEAK SHORT WAVE
AND MID LEVEL MOISTURE ADVECTION. RUC13 AND HRRR TO SOME EXTENT
ONLY MODELS PICKING UP ON THESE CLOUDS WITH RUC13 850-700MB RH
FIELDS HANDLING IT THE BEST. THIS GUIDANCE AND SATELLITE LOOPS
SUPPPORT A SOUTHEAST MOVEMENT AND EXPECT THESE CLOUDS INTO KSBN IN
NEXT FEW HOURS AND KFWA TOWARD DAYBREAK. SOUNDINGS AND CROSS SECTIONS
SUGGEST CLOUDS TO LINGER THROUGH MID TO LATE MORNING BEFORE MIXING
AND MOVING SOUTH. OTHERWISE LIGHT AND VARIABLE WINDS GENERALLY
UNDER 10 KNOTS THROUGH THE PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...FISHER
LONG TERM...JT
AVIATION...LASHLEY
AREA FORECAST DISCUSSION
NWS JACKSON KY
133 PM EDT FRI MAR 29 2013
.UPDATE...
ISSUED AT 1253 PM EDT FRI MAR 29 2013
HAVE UPDATED NDFD AND ZFP FOR LATEST OBSERVATIONAL TRENDS. RAIN HAS
MEASURED AT MONTICELLO AND IT HAS STARTED RAINING AT SME. MAIN
CHANGES WERE TO REDUCE THE NORTHERN EXTENT OF ANY RAIN CHANCES. HAVE
ALSO LOWERED MAXIMUM TEMPERATURES IN THE SOUTH WHERE EXTENSIVE CLOUD
COVER WILL PERSIST THIS AFTERNOON.
UPDATE ISSUED AT 948 AM EDT FRI MAR 29 2013
MESONET DATA SHOWING MEASURABLE RAIN HAS OCCURRED OVER MOST OF WESTERN
KY AND AS FAR SOUTHEAST AS CUMBERLAND COUNTY. RAIN ALSO FALLING AS
FAR NORTH AS EVV INDIANA. RADAR SHOWS MOVEMENT OF RAIN TO THE ESE...SO
EXPECT NUMEROUS SHOWERS TO AFFECT THE FAR SOUTHWEST AND FAR SOUTHERN
PART OF THE FORECAST AREA. THIS IS SUPPORTED BY SREF PROBABILITIES
AND LATEST DATA FROM THE HRRR AND NAM. AS SUCH HAVE UPDATED NDFD AND
ZFP TO INCREASE RAIN PROBABILITIES IN THE FAR SOUTHWEST AND FAR SOUTH
TODAY.
UPDATE ISSUED AT 740 AM EDT FRI MAR 29 2013
UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL
TRENDS. ONLY MADE SOME SLIGHT CHANGES TO TEMPERATURES...DEW POINTS
CLOUDS AND WINDS IN THE FIRST TWO PERIODS. THE REST OF THE FORECAST
IS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 308 AM EDT FRI MAR 29 2013
A WEAK WEATHER SYSTEM WILL BRING SOME LIGHT RAIN TO THE SOUTHWESTERN
HALF OF EASTERN KENTUCKY TODAY. THIS SYSTEM IS A WARM FRONT WHICH
WILL TRY MOVING INTO THE AREA BUT THEN BE PUSHED BACK TO THE SOUTH
TONIGHT. THIS WILL MAKE FOR A DRY SATURDAY BEFORE THE NEXT SYSTEM
STARTS PUSHING ITS WAY INTO THE AREA ON SATURDAY NIGHT. THE JURY IS
OUT ABOUT HOW MUCH RAIN THE WEAK SYSTEM TODAY WILL BE ABLE TO
PRODUCE. IT MAY BE A LOT OF CLOUDS AND SOME SPRINKLES...AT BEST AND
JUST A COUPLE OF HUNDREDTHS OF AN INCH OF RAIN AT THE WORST. AS YOU
MOVE TO THE NORTHEAST FROM WAYNE COUNTY...THE CHANCE FOR MEASURABLE
RAIN DECREASES. EXPECTING HIGHS IN THE MID 50S TODAY AND THEN NEAR 60
ON SATURDAY AS SOME WARMER AIR WORKS ITS WAY INTO THE AREA.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 412 AM EDT FRI MAR 29 2013
THE GFS AND ECMWF ARE IN GOOD AGREEMENT THROUGH THE PERIOD. FOR THE
LOCAL AREA THEY SHOW A WARM AIR ADVECTION REGIME DEVELOPING IN
ADVANCE OF A COLD FRONT SATURDAY NIGHT...WITH THE COLD FRONT THEN
PASSING THROUGH ON SUNDAY. THERE APPEARS TO BE A DECENT AMOUNT OF
MOISTURE WHICH MAKES ITS WAY IN FROM THE GULF BEFORE THE FRONT
ARRIVES...AND LIKELY POPS FROM GFS MEXMOS SEEM REASONABLE. MARGINAL
DEEP INSTABILITY IS ALSO INDICATED...AND IS WORTH A MENTION OF A
SLIGHT CHANCE OF THUNDER.
ANY LINGERING PRECIP IN THE SOUTH AND EAST ASSOCIATED WITH THE COLD
FRONT SHOULD EXIT MONDAY EVENING. HOWEVER...THERE IS ADDITIONAL
POTENTIAL FOR MORE PRECIP TOWARD THE END OF THE NIGHT...ALBEIT SMALL.
THE NAM SHOWS A WAVE PASSING TO OUR SOUTH AND GRAZING OUR
AREA...WHILE THE GFS AND ECMWF ARE FURTHER SOUTH WITH IT. WITH THE
NAM BEING THE ONLY MODEL THAT EVEN GETS PRECIP TO THE EDGE OF OUR
AREA...WILL NOT BRING ANY PRECIP INTO THE LOCAL AREA WITH THIS
SYSTEM. HOWEVER...ALL THREE MODELS SHOW ANOTHER COLD FRONT MOVING IN
FROM THE NW TOWARD MONDAY MORNING. WHILE THEY KEEP THE DEEP MOISTURE
WITH THE FRONT NEAR OR NORTH OF THE OHIO RIVER...CONFIDENCE IN
TIMING IS NOT GOOD ENOUGH TO PRECLUDE PRECIP HERE...AND HAVE ALLOWED
FOR A SLIGHT CHANCE IN THE NORTH AT DAWN. WILL USE CHANCE POPS FOR
RAIN ON MONDAY AS THE FRONT MOVES THROUGH. HAVE RESERVED THE HIGHEST
POPS WITH THIS FRONT...STILL IN CHANCE CATEGORY...FOR MONDAY NIGHT
AS A WAVE MOVES ALONG THE FRONT AFTER IT HAS PASSED. UP UNTIL MONDAY
THE PRECIP FORM SHOULD BE LIQUID...BUT ENOUGH COLD AIR ARRIVES TO
THREATEN SNOW BEFORE POPS DROP OFF LATE MONDAY NIGHT.
LARGE...COLD...SPRAWLING SURFACE HIGH PRESSURE THEN HEADS IN FROM THE
NW AND IS EXPECTED TO BRING DRY WEATHER INTO THURSDAY. LOW PRESSURE
PASSING WELL TO OUR SOUTH THURSDAY AND THURSDAY NIGHT LOOKS AT THIS
POINT LIKE IT WILL GRAZE THE SOUTHERN PART OF THE FORECAST AREA WITH
RAIN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 133 PM EDT FRI MAR 29 2013
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD. A WEAK
WEATHER DISTURBANCE WILL BRING LIGHT RAIN TO THE EXTREME SOUTHERN
PART OF THE FORECAST AREA THIS AFTERNOON...WELL SOUTH OF JKL...AND
MAINLY SOUTH OF SME AND LOZ AS WELL. WHERE THE RAIN OCCURS LOCAL MVFR
TO IFR CONDITIONS ARE POSSIBLE...MAINLY WITH LOWER VISIBILITIES.
OUTSIDE OF THE RAIN AREA VFR CONDITIONS WILL PREVAIL TODAY. DEWPOINTS
HAVE INCREASED IN THE FAR SOUTH TODAY...AND IF CLOUDS BREAK TONIGHT
SOME FOG IS POSSIBLE. HOWEVER...AT THIS POINT EXPECT EXTENSIVE
CLOUDINESS IN THE SOUTHERN PART OF THE FORECAST AREA TO LIMIT FOG
FORMATION TONIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...JJ
LONG TERM...HAL
AVIATION...SBH
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
109 PM EDT FRI MAR 29 2013
...Updated Aviation Discussion...
.Short Term (Now - Saturday)...
Issued at 300 AM EDT Fri Mar 29 2013
An upper level shortwave and weak sfc boundary were located to our
WSW early this morning producing showers and t-storms from eastern
KS to western KY. The latest RAP model guidance seems to be
handling this area of precip quite well, so have relied on it for
short term POPs. Rain showers look likely across portions of south
central KY this morning before moving south of the area into TN this
afternoon. Think that better lapse rates out west are producing the
t-storms with this wave and do not anticipate those better lapse
rates to translate eastward so will not include thunder in this
forecast. For high temperatures today, have gone with mid 50s over
southern Indiana and north central KY which will see less cloud
cover overall and no precip. Lower 50s can be expected for highs
over south central KY where rain is anticipated.
Tonight sfc high pressure will quickly work in from the north
allowing for dry conditions and only partly cloudy skies across
southern IN and northern KY. Went with a decent temp gradient due
to cloud cover with low to mid 30s for lows over southern
IN/northern KY to upper 30s and lower 40s over south central KY.
The next push of moisture doesn`t look to arrive until late Sat
afternoon or evening as a warm front pushes into south central KY.
Therefore, limited POP chances to just the afternoon hours over
south central KY for Sat. The rest of the area should be dry and
warm up quite nicely. With only partly cloudy skies anticipated
during the morning and early afternoon, went with high temps in the
low to mid 60s.
.Long Term (Saturday Night - Thursday)...
Issued at 300 AM EDT Fri Mar 29 2013
Cold front number one will be fast approaching from the northwest
Saturday night. Rain and a few embedded rumbles of thunder will
overspread the forecast area Saturday night and through the morning
hours Sunday. Rain chances will diminish from west to east late
Sunday morning, with a dry period anticipated from roughly Sunday
afternoon through Sunday night. A second cold front will quickly
enter the forecast area from the north Monday and sag south through
Monday night. Expect rain chances to increase through the day Monday
and rain should exit the southern CWA by Tuesday morning.
Temperatures will fall behind the front Monday night and soundings
indicate the potential for some smaller ice crystal growth. It
appears the loss of moisture/ice crystals within the dendritic
growth layer will limit large snowflake generation. So, there could
be some light snow mixed with the rain overnight as the system
exits.
Then, high pressure will build across the Ohio Valley, with the
active storm track being pushed well to our south. The only question
is whether a southern track system Thursday will be deep enough to
increase moisture and rain potential across the Ohio and Tennessee
Valleys as it tracks across the Gulf States. Rain probabilities are
low for Thursday, with an overall slower trend noted in latest
guidance. Will go with a dry forecast Tuesday through Thursday, with
perhaps a slight rain chance across our south and southeast CWA just
beyond the long-term period.
The cold front that swings through the area early Sunday will not be
followed by a cold air mass. Still expect temperatures in the 60s
Sunday afternoon. However, the passage of the second front on Monday
will bring a return to unseasonably cool conditions through
Thursday. The good news is temperatures appear to moderate some
through the work week. So, while highs in the 40s are expected
Tuesday, highs Thursday appear to reach the middle 50s.
&&
.Aviation (18Z TAF Issuance)...
Issued at 109 PM EDT Fri Mar 29 2013
Ceilings are the main challenge with this forecast package.
Mesoscale models are showing MVFR clouds forming to our west early
this afternoon and spreading eastward by mid and late afternoon,
particularly over southern Kentucky. Recent obs show that some low
stratus has indeed formed across southeast Missouri and southern
Illinois. In southern Kentucky, GLW has started reporting a ceiling
at 032. Will go ahead and bring an MVFR ceiling into BWG, but will
keep it on the high side of MVFR -- above 2000 feet. Will monitor
to see if we need to go lower.
The rain at BWG should cease around 19Z.
The northern TAF sites should stay VFR. Winds at all three sites
will remain light and variable.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......AMS
Long Term........MJP
Aviation.........13
AREA FORECAST DISCUSSION
NWS JACKSON KY
1254 PM EDT FRI MAR 29 2013
.UPDATE...
ISSUED AT 1253 PM EDT FRI MAR 29 2013
HAVE UPDATED NDFD AND ZFP FOR LATEST OBSERVATIONAL TRENDS. RAIN HAS
MEASURED AT MONTICELLO AND IT HAS STARTED RAINING AT SME. MAIN
CHANGES WERE TO REDUCE THE NORTHERN EXTENT OF ANY RAIN CHANCES. HAVE
ALSO LOWERED MAXIMUM TEMPERATURES IN THE SOUTH WHERE EXTENSIVE CLOUD
COVER WILL PERSIST THIS AFTERNOON.
UPDATE ISSUED AT 948 AM EDT FRI MAR 29 2013
MESONET DATA SHOWING MEASURABLE RAIN HAS OCCURRED OVER MOST OF WESTERN
KY AND AS FAR SOUTHEAST AS CUMBERLAND COUNTY. RAIN ALSO FALLING AS
FAR NORTH AS EVV INDIANA. RADAR SHOWS MOVEMENT OF RAIN TO THE ESE...SO
EXPECT NUMEROUS SHOWERS TO AFFECT THE FAR SOUTHWEST AND FAR SOUTHERN
PART OF THE FORECAST AREA. THIS IS SUPPORTED BY SREF PROBABILITIES
AND LATEST DATA FROM THE HRRR AND NAM. AS SUCH HAVE UPDATED NDFD AND
ZFP TO INCREASE RAIN PROBABILITIES IN THE FAR SOUTHWEST AND FAR SOUTH
TODAY.
UPDATE ISSUED AT 740 AM EDT FRI MAR 29 2013
UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL
TRENDS. ONLY MADE SOME SLIGHT CHANGES TO TEMPERATURES...DEW POINTS
CLOUDS AND WINDS IN THE FIRST TWO PERIODS. THE REST OF THE FORECAST
IS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 308 AM EDT FRI MAR 29 2013
A WEAK WEATHER SYSTEM WILL BRING SOME LIGHT RAIN TO THE SOUTHWESTERN
HALF OF EASTERN KENTUCKY TODAY. THIS SYSTEM IS A WARM FRONT WHICH
WILL TRY MOVING INTO THE AREA BUT THEN BE PUSHED BACK TO THE SOUTH
TONIGHT. THIS WILL MAKE FOR A DRY SATURDAY BEFORE THE NEXT SYSTEM
STARTS PUSHING ITS WAY INTO THE AREA ON SATURDAY NIGHT. THE JURY IS
OUT ABOUT HOW MUCH RAIN THE WEAK SYSTEM TODAY WILL BE ABLE TO
PRODUCE. IT MAY BE A LOT OF CLOUDS AND SOME SPRINKLES...AT BEST AND
JUST A COUPLE OF HUNDREDTHS OF AN INCH OF RAIN AT THE WORST. AS YOU
MOVE TO THE NORTHEAST FROM WAYNE COUNTY...THE CHANCE FOR MEASURABLE
RAIN DECREASES. EXPECTING HIGHS IN THE MID 50S TODAY AND THEN NEAR 60
ON SATURDAY AS SOME WARMER AIR WORKS ITS WAY INTO THE AREA.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 412 AM EDT FRI MAR 29 2013
THE GFS AND ECMWF ARE IN GOOD AGREEMENT THROUGH THE PERIOD. FOR THE
LOCAL AREA THEY SHOW A WARM AIR ADVECTION REGIME DEVELOPING IN
ADVANCE OF A COLD FRONT SATURDAY NIGHT...WITH THE COLD FRONT THEN
PASSING THROUGH ON SUNDAY. THERE APPEARS TO BE A DECENT AMOUNT OF
MOISTURE WHICH MAKES ITS WAY IN FROM THE GULF BEFORE THE FRONT
ARRIVES...AND LIKELY POPS FROM GFS MEXMOS SEEM REASONABLE. MARGINAL
DEEP INSTABILITY IS ALSO INDICATED...AND IS WORTH A MENTION OF A
SLIGHT CHANCE OF THUNDER.
ANY LINGERING PRECIP IN THE SOUTH AND EAST ASSOCIATED WITH THE COLD
FRONT SHOULD EXIT MONDAY EVENING. HOWEVER...THERE IS ADDITIONAL
POTENTIAL FOR MORE PRECIP TOWARD THE END OF THE NIGHT...ALBEIT SMALL.
THE NAM SHOWS A WAVE PASSING TO OUR SOUTH AND GRAZING OUR
AREA...WHILE THE GFS AND ECMWF ARE FURTHER SOUTH WITH IT. WITH THE
NAM BEING THE ONLY MODEL THAT EVEN GETS PRECIP TO THE EDGE OF OUR
AREA...WILL NOT BRING ANY PRECIP INTO THE LOCAL AREA WITH THIS
SYSTEM. HOWEVER...ALL THREE MODELS SHOW ANOTHER COLD FRONT MOVING IN
FROM THE NW TOWARD MONDAY MORNING. WHILE THEY KEEP THE DEEP MOISTURE
WITH THE FRONT NEAR OR NORTH OF THE OHIO RIVER...CONFIDENCE IN
TIMING IS NOT GOOD ENOUGH TO PRECLUDE PRECIP HERE...AND HAVE ALLOWED
FOR A SLIGHT CHANCE IN THE NORTH AT DAWN. WILL USE CHANCE POPS FOR
RAIN ON MONDAY AS THE FRONT MOVES THROUGH. HAVE RESERVED THE HIGHEST
POPS WITH THIS FRONT...STILL IN CHANCE CATEGORY...FOR MONDAY NIGHT
AS A WAVE MOVES ALONG THE FRONT AFTER IT HAS PASSED. UP UNTIL MONDAY
THE PRECIP FORM SHOULD BE LIQUID...BUT ENOUGH COLD AIR ARRIVES TO
THREATEN SNOW BEFORE POPS DROP OFF LATE MONDAY NIGHT.
LARGE...COLD...SPRAWLING SURFACE HIGH PRESSURE THEN HEADS IN FROM THE
NW AND IS EXPECTED TO BRING DRY WEATHER INTO THURSDAY. LOW PRESSURE
PASSING WELL TO OUR SOUTH THURSDAY AND THURSDAY NIGHT LOOKS AT THIS
POINT LIKE IT WILL GRAZE THE SOUTHERN PART OF THE FORECAST AREA WITH
RAIN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 740 AM EDT FRI MAR 29 2013
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. HIGH CLOUDS AND
MIDDLE CLOUDS HAVE ARRIVED AND WILL BE LOWERING THROUGH THE DAY
TODAY. ISOLATED LIGHT SHOWER POSSIBLE BY MID DAY IN THE CUMBERLAND
VALLEY. MAINTAINED A VCSH AND CIGS AROUND 5K FEET FOR THIS IN THE LOZ
AND SME TAFS. WINDS WILL HAVE A W TO WNW TENDENCY...AT 5 KTS OR LESS
THROUGH THE PERIOD AS WELL.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...JJ
LONG TERM...HAL
AVIATION...JJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
948 AM EDT FRI MAR 29 2013
.UPDATE...
ISSUED AT 948 AM EDT FRI MAR 29 2013
MESONET DATA SHOWING MEASURABLE RAIN HAS OCCURRED OVER MOST OF WESTERN
KY AND AS FAR SOUTHEAST AS CUMBERLAND COUNTY. RAIN ALSO FALLING AS
FAR NORTH AS EVV INDIANA. RADAR SHOWS MOVEMENT OF RAIN TO THE ESE...SO
EXPECT NUMEROUS SHOWERS TO AFFECT THE FAR SOUTHWEST AND FAR SOUTHERN
PART OF THE FORECAST AREA. THIS IS SUPPORTED BY SREF PROBABILITIES
AND LATEST DATA FROM THE HRRR AND NAM. AS SUCH HAVE UPDATED NDFD AND
ZFP TO INCREASE RAIN PROBABILITIES IN THE FAR SOUTHWEST AND FAR SOUTH
TODAY.
UPDATE ISSUED AT 740 AM EDT FRI MAR 29 2013
UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL
TRENDS. ONLY MADE SOME SLIGHT CHANGES TO TEMPERATURES...DEW POINTS
CLOUDS AND WINDS IN THE FIRST TWO PERIODS. THE REST OF THE FORECAST
IS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 308 AM EDT FRI MAR 29 2013
A WEAK WEATHER SYSTEM WILL BRING SOME LIGHT RAIN TO THE SOUTHWESTERN
HALF OF EASTERN KENTUCKY TODAY. THIS SYSTEM IS A WARM FRONT WHICH
WILL TRY MOVING INTO THE AREA BUT THEN BE PUSHED BACK TO THE SOUTH
TONIGHT. THIS WILL MAKE FOR A DRY SATURDAY BEFORE THE NEXT SYSTEM
STARTS PUSHING ITS WAY INTO THE AREA ON SATURDAY NIGHT. THE JURY IS
OUT ABOUT HOW MUCH RAIN THE WEAK SYSTEM TODAY WILL BE ABLE TO
PRODUCE. IT MAY BE A LOT OF CLOUDS AND SOME SPRINKLES...AT BEST AND
JUST A COUPLE OF HUNDREDTHS OF AN INCH OF RAIN AT THE WORST. AS YOU
MOVE TO THE NORTHEAST FROM WAYNE COUNTY...THE CHANCE FOR MEASURABLE
RAIN DECREASES. EXPECTING HIGHS IN THE MID 50S TODAY AND THEN NEAR 60
ON SATURDAY AS SOME WARMER AIR WORKS ITS WAY INTO THE AREA.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 412 AM EDT FRI MAR 29 2013
THE GFS AND ECMWF ARE IN GOOD AGREEMENT THROUGH THE PERIOD. FOR THE
LOCAL AREA THEY SHOW A WARM AIR ADVECTION REGIME DEVELOPING IN
ADVANCE OF A COLD FRONT SATURDAY NIGHT...WITH THE COLD FRONT THEN
PASSING THROUGH ON SUNDAY. THERE APPEARS TO BE A DECENT AMOUNT OF
MOISTURE WHICH MAKES ITS WAY IN FROM THE GULF BEFORE THE FRONT
ARRIVES...AND LIKELY POPS FROM GFS MEXMOS SEEM REASONABLE. MARGINAL
DEEP INSTABILITY IS ALSO INDICATED...AND IS WORTH A MENTION OF A
SLIGHT CHANCE OF THUNDER.
ANY LINGERING PRECIP IN THE SOUTH AND EAST ASSOCIATED WITH THE COLD
FRONT SHOULD EXIT MONDAY EVENING. HOWEVER...THERE IS ADDITIONAL
POTENTIAL FOR MORE PRECIP TOWARD THE END OF THE NIGHT...ALBEIT SMALL.
THE NAM SHOWS A WAVE PASSING TO OUR SOUTH AND GRAZING OUR
AREA...WHILE THE GFS AND ECMWF ARE FURTHER SOUTH WITH IT. WITH THE
NAM BEING THE ONLY MODEL THAT EVEN GETS PRECIP TO THE EDGE OF OUR
AREA...WILL NOT BRING ANY PRECIP INTO THE LOCAL AREA WITH THIS
SYSTEM. HOWEVER...ALL THREE MODELS SHOW ANOTHER COLD FRONT MOVING IN
FROM THE NW TOWARD MONDAY MORNING. WHILE THEY KEEP THE DEEP MOISTURE
WITH THE FRONT NEAR OR NORTH OF THE OHIO RIVER...CONFIDENCE IN
TIMING IS NOT GOOD ENOUGH TO PRECLUDE PRECIP HERE...AND HAVE ALLOWED
FOR A SLIGHT CHANCE IN THE NORTH AT DAWN. WILL USE CHANCE POPS FOR
RAIN ON MONDAY AS THE FRONT MOVES THROUGH. HAVE RESERVED THE HIGHEST
POPS WITH THIS FRONT...STILL IN CHANCE CATEGORY...FOR MONDAY NIGHT
AS A WAVE MOVES ALONG THE FRONT AFTER IT HAS PASSED. UP UNTIL MONDAY
THE PRECIP FORM SHOULD BE LIQUID...BUT ENOUGH COLD AIR ARRIVES TO
THREATEN SNOW BEFORE POPS DROP OFF LATE MONDAY NIGHT.
LARGE...COLD...SPRAWLING SURFACE HIGH PRESSURE THEN HEADS IN FROM THE
NW AND IS EXPECTED TO BRING DRY WEATHER INTO THURSDAY. LOW PRESSURE
PASSING WELL TO OUR SOUTH THURSDAY AND THURSDAY NIGHT LOOKS AT THIS
POINT LIKE IT WILL GRAZE THE SOUTHERN PART OF THE FORECAST AREA WITH
RAIN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 740 AM EDT FRI MAR 29 2013
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. HIGH CLOUDS AND
MIDDLE CLOUDS HAVE ARRIVED AND WILL BE LOWERING THROUGH THE DAY
TODAY. ISOLATED LIGHT SHOWER POSSIBLE BY MID DAY IN THE CUMBERLAND
VALLEY. MAINTAINED A VCSH AND CIGS AROUND 5K FEET FOR THIS IN THE LOZ
AND SME TAFS. WINDS WILL HAVE A W TO WNW TENDENCY...AT 5 KTS OR LESS
THROUGH THE PERIOD AS WELL.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...JJ
LONG TERM...HAL
AVIATION...JJ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
926 AM EDT FRI MAR 29 2013
.Forecast Update...
Issued at 926 AM EDT Fri Mar 29 2013
Quick update to raise PoPs to 100% where it is currently raining and
sky cover to 100% where it is currently overcast. Also bumped up
precipitation amounts a bit based on totals coming in from western
Kentucky this morning.
&&
.Short Term (Now - Saturday)...
Issued at 300 AM EDT Fri Mar 29 2013
An upper level shortwave and weak sfc boundary were located to our
WSW early this morning producing showers and t-storms from eastern
KS to western KY. The latest RAP model guidance seems to be
handling this area of precip quite well, so have relied on it for
short term POPs. Rain showers look likely across portions of south
central KY this morning before moving south of the area into TN this
afternoon. Think that better lapse rates out west are producing the
t-storms with this wave and do not anticipate those better lapse
rates to translate eastward so will not include thunder in this
forecast. For high temperatures today, have gone with mid 50s over
southern Indiana and north central KY which will see less cloud
cover overall and no precip. Lower 50s can be expected for highs
over south central KY where rain is anticipated.
Tonight sfc high pressure will quickly work in from the north
allowing for dry conditions and only partly cloudy skies across
southern IN and northern KY. Went with a decent temp gradient due
to cloud cover with low to mid 30s for lows over southern
IN/northern KY to upper 30s and lower 40s over south central KY.
The next push of moisture doesn`t look to arrive until late Sat
afternoon or evening as a warm front pushes into south central KY.
Therefore, limited POP chances to just the afternoon hours over
south central KY for Sat. The rest of the area should be dry and
warm up quite nicely. With only partly cloudy skies anticipated
during the morning and early afternoon, went with high temps in the
low to mid 60s.
.Long Term (Saturday Night - Thursday)...
Issued at 300 AM EDT Fri Mar 29 2013
Cold front number one will be fast approaching from the northwest
Saturday night. Rain and a few embedded rumbles of thunder will
overspread the forecast area Saturday night and through the morning
hours Sunday. Rain chances will diminish from west to east late
Sunday morning, with a dry period anticipated from roughly Sunday
afternoon through Sunday night. A second cold front will quickly
enter the forecast area from the north Monday and sag south through
Monday night. Expect rain chances to increase through the day Monday
and rain should exit the southern CWA by Tuesday morning.
Temperatures will fall behind the front Monday night and soundings
indicate the potential for some smaller ice crystal growth. It
appears the loss of moisture/ice crystals within the dendritic
growth layer will limit large snowflake generation. So, there could
be some light snow mixed with the rain overnight as the system
exits.
Then, high pressure will build across the Ohio Valley, with the
active storm track being pushed well to our south. The only question
is whether a southern track system Thursday will be deep enough to
increase moisture and rain potential across the Ohio and Tennessee
Valleys as it tracks across the Gulf States. Rain probabilities are
low for Thursday, with an overall slower trend noted in latest
guidance. Will go with a dry forecast Tuesday through Thursday, with
perhaps a slight rain chance across our south and southeast CWA just
beyond the long-term period.
The cold front that swings through the area early Sunday will not be
followed by a cold air mass. Still expect temperatures in the 60s
Sunday afternoon. However, the passage of the second front on Monday
will bring a return to unseasonably cool conditions through
Thursday. The good news is temperatures appear to moderate some
through the work week. So, while highs in the 40s are expected
Tuesday, highs Thursday appear to reach the middle 50s.
&&
.Aviation (12Z TAF Issuance)...
Issued at 645 AM EDT Fri Mar 29 2013
VFR conditions are expected for this TAF period. Mid and upper
level clouds will continue to stream into the area this morning and
continue through the day as an upper level shortwave passes through
south central KY. This wave looks to bring precip in the form of
rain showers to BWG today. These showers have made it into the BWG
terminal with the main push of moisture progged to occur from
roughly 13Z-20Z. SDF/LEX still look to remain dry although will
need to monitor the northern extent of the precip shield to make
sure it doesn`t creep into SDF. The 0Z NAM indicates MVFR
conditions will develop at BWG today, but feel it is an outlier at
this point compared to other model runs and upstream obs. Still
will need to watch BWG for some cig/vsby restrictions today.
Winds will be hard to pin down throughout the TAF period. Generally
they will remain light (under 5 kts). Variable winds can be
expected during the early morning hours and again tonight.
Think that the predominant wind direction at BWG this afternoon will
be SSE with SDF/LEX winds predominantly SSW.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........13
Short Term.......AMS
Long Term........MJP
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
648 AM EDT FRI MAR 29 2013
...Updated Aviation Discussion...
.Short Term (Now - Saturday)...
Issued at 300 AM EDT Fri Mar 29 2013
An upper level shortwave and weak sfc boundary were located to our
WSW early this morning producing showers and t-storms from eastern
KS to western KY. The latest RAP model guidance seems to be
handling this area of precip quite well, so have relied on it for
short term POPs. Rain showers look likely across portions of south
central KY this morning before moving south of the area into TN this
afternoon. Think that better lapse rates out west are producing the
t-storms with this wave and do not anticipate those better lapse
rates to translate eastward so will not include thunder in this
forecast. For high temperatures today, have gone with mid 50s over
southern Indiana and north central KY which will see less cloud
cover overall and no precip. Lower 50s can be expected for highs
over south central KY where rain is anticipated.
Tonight sfc high pressure will quickly work in from the north
allowing for dry conditions and only partly cloudy skies across
southern IN and northern KY. Went with a decent temp gradient due
to cloud cover with low to mid 30s for lows over southern
IN/northern KY to upper 30s and lower 40s over south central KY.
The next push of moisture doesn`t look to arrive until late Sat
afternoon or evening as a warm front pushes into south central KY.
Therefore, limited POP chances to just the afternoon hours over
south central KY for Sat. The rest of the area should be dry and
warm up quite nicely. With only partly cloudy skies anticipated
during the morning and early afternoon, went with high temps in the
low to mid 60s.
.Long Term (Saturday Night - Thursday)...
Issued at 300 AM EDT Fri Mar 29 2013
Cold front number one will be fast approaching from the northwest
Saturday night. Rain and a few embedded rumbles of thunder will
overspread the forecast area Saturday night and through the morning
hours Sunday. Rain chances will diminish from west to east late
Sunday morning, with a dry period anticipated from roughly Sunday
afternoon through Sunday night. A second cold front will quickly
enter the forecast area from the north Monday and sag south through
Monday night. Expect rain chances to increase through the day Monday
and rain should exit the southern CWA by Tuesday morning.
Temperatures will fall behind the front Monday night and soundings
indicate the potential for some smaller ice crystal growth. It
appears the loss of moisture/ice crystals within the dendritic
growth layer will limit large snowflake generation. So, there could
be some light snow mixed with the rain overnight as the system
exits.
Then, high pressure will build across the Ohio Valley, with the
active storm track being pushed well to our south. The only question
is whether a southern track system Thursday will be deep enough to
increase moisture and rain potential across the Ohio and Tennessee
Valleys as it tracks across the Gulf States. Rain probabilities are
low for Thursday, with an overall slower trend noted in latest
guidance. Will go with a dry forecast Tuesday through Thursday, with
perhaps a slight rain chance across our south and southeast CWA just
beyond the long-term period.
The cold front that swings through the area early Sunday will not be
followed by a cold air mass. Still expect temperatures in the 60s
Sunday afternoon. However, the passage of the second front on Monday
will bring a return to unseasonably cool conditions through
Thursday. The good news is temperatures appear to moderate some
through the work week. So, while highs in the 40s are expected
Tuesday, highs Thursday appear to reach the middle 50s.
&&
.Aviation (12Z TAF Issuance)...
Issued at 645 AM EDT Fri Mar 29 2013
VFR conditions are expected for this TAF period. Mid and upper
level clouds will continue to stream into the area this morning and
continue through the day as an upper level shortwave passes through
south central KY. This wave looks to bring precip in the form of
rain showers to BWG today. These showers have made it into the BWG
terminal with the main push of moisture progged to occur from
roughly 13Z-20Z. SDF/LEX still look to remain dry although will
need to monitor the northern extent of the precip shield to make
sure it doesn`t creep into SDF. The 0Z NAM indicates MVFR
conditions will develop at BWG today, but feel it is an outlier at
this point compared to other model runs and upstream obs. Still
will need to watch BWG for some cig/vsby restrictions today.
Winds will be hard to pin down throughout the TAF period. Generally
they will remain light (under 5 kts). Variable winds can be
expected during the early morning hours and again tonight.
Think that the predominant wind direction at BWG this afternoon will
be SSE with SDF/LEX winds predominantly SSW.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......AMS
Long Term........MJP
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
317 AM EDT FRI MAR 29 2013
.Short Term (Now - Saturday)...
Issued at 300 AM EDT Fri Mar 29 2013
An upper level shortwave and weak sfc boundary were located to our
WSW early this morning producing showers and t-storms from eastern
KS to western KY. The latest RAP model guidance seems to be
handling this area of precip quite well, so have relied on it for
short term POPs. Rain showers look likely across portions of south
central KY this morning before moving south of the area into TN this
afternoon. Think that better lapse rates out west are producing the
t-storms with this wave and do not anticipate those better lapse
rates to translate eastward so will not include thunder in this
forecast. For high temperatures today, have gone with mid 50s over
southern Indiana and north central KY which will see less cloud
cover overall and no precip. Lower 50s can be expected for highs
over south central KY where rain is anticipated.
Tonight sfc high pressure will quickly work in from the north
allowing for dry conditions and only partly cloudy skies across
southern IN and northern KY. Went with a decent temp gradient due
to cloud cover with low to mid 30s for lows over southern
IN/northern KY to upper 30s and lower 40s over south central KY.
The next push of moisture doesn`t look to arrive until late Sat
afternoon or evening as a warm front pushes into south central KY.
Therefore, limited POP chances to just the afternoon hours over
south central KY for Sat. The rest of the area should be dry and
warm up quite nicely. With only partly cloudy skies anticipated
during the morning and early afternoon, went with high temps in the
low to mid 60s.
.Long Term (Saturday Night - Thursday)...
Issued at 300 AM EDT Fri Mar 29 2013
Cold front number one will be fast approaching from the northwest
Saturday night. Rain and a few embedded rumbles of thunder will
overspread the forecast area Saturday night and through the morning
hours Sunday. Rain chances will diminish from west to east late
Sunday morning, with a dry period anticipated from roughly Sunday
afternoon through Sunday night. A second cold front will quickly
enter the forecast area from the north Monday and sag south through
Monday night. Expect rain chances to increase through the day Monday
and rain should exit the southern CWA by Tuesday morning.
Temperatures will fall behind the front Monday night and soundings
indicate the potential for some smaller ice crystal growth. It
appears the loss of moisture/ice crystals within the dendritic
growth layer will limit large snowflake generation. So, there could
be some light snow mixed with the rain overnight as the system
exits.
Then, high pressure will build across the Ohio Valley, with the
active storm track being pushed well to our south. The only question
is whether a southern track system Thursday will be deep enough to
increase moisture and rain potential across the Ohio and Tennessee
Valleys as it tracks across the Gulf States. Rain probabilities are
low for Thursday, with an overall slower trend noted in latest
guidance. Will go with a dry forecast Tuesday through Thursday, with
perhaps a slight rain chance across our south and southeast CWA just
beyond the long-term period.
The cold front that swings through the area early Sunday will not be
followed by a cold air mass. Still expect temperatures in the 60s
Sunday afternoon. However, the passage of the second front on Monday
will bring a return to unseasonably cool conditions through
Thursday. The good news is temperatures appear to moderate some
through the work week. So, while highs in the 40s are expected
Tuesday, highs Thursday appear to reach the middle 50s.
&&
.Aviation (06Z TAF Issuance)...
Issued at 105 AM EDT Fri Mar 29 2013
VFR conditions are expected for this TAF period. Mid and upper
level clouds will continue to stream into the area overnight and
continue through the day as an upper level shortwave passes through
south central KY. This wave looks to bring precip in the form of
rain showers to BWG today. These showers have made it as far east
as western KY and a few will likely make it into the BWG TAF within
the next 1-3 hrs. The main push of moisture should hold off until
later this morning with light steady rain showers expected from
roughly 13Z-20Z. SDF/LEX still look to remain dry. The 0Z NAM
indicates MVFR conditions will develop at BWG today, but feel it is
an outlier at this point compared to other model runs and upstream
obs. Still will need to watch BWG for some cig/vsby restrictions
today.
Winds will be hard to pin down throughout the TAF period. Generally
they will remain light (under 5 kts). Variable winds can be
expected during the early morning hours and again this evening.
Think that the predominant wind direction at BWG this afternoon will
be SSE with SDF/LEX winds predominantly SSW.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......AMS
Long Term........MJP
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
840 PM EDT SAT MAR 30 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 453 PM EDT SAT MAR 30 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A RIDGE OVER THE FAR WRN
CONUS INTO WRN CANADA WHILE DOWNSTREAM TROF WAS AMPLIFYING S THRU
CNTRL CANADA INTO THE NCNTRL CONUS. WITHIN THE DEEPENING TROF...A
SHORTWAVE MOVING ACROSS THE UPPER GREAT LAKES HAS BROUGHT A BAND OF
PCPN TO UPPER MI TODAY. PCPN WAS MAINLY RAIN OVER THE W...BUT MIXED
WITH/CHANGED TO SNOW OVER THE CNTRL/E. SNOW WAS MDT/HVY ACROSS
IRON/DICKINSON COUNTIES WHERE A FEW INCHES OF WET SNOW ACCUMULATION
HAS BEEN REPORTED. THE HEAVIER SNOW IS NOW STREAKING E TOWARD LUCE
COUNTY. BACKEDGE OF THE MAIN PCPN AREA WAS OVER CNTRL UPPER MI AS OF
20Z. WITH DEPARTURE OF THIS AREA OF PCPN...ATTENTION IN THE SHORT
TERM SHIFTS TO SHORTWAVE DIGGING SHARPLY INTO THE UPPER GREAT LAKES
LATE TONIGHT/SUN AND THE INCREASINGLY COLDER AIR IT WILL BRING.
INCORPORATING EXTRAPOLATION FOR ENDING PCPN...EXPECT STEADIER PCPN
TO EXIT THE ERN FCST AREA AROUND 03Z WITH ALL OF THE AREA DRY BY
06Z. MAY SEE AN INCH OR SO OF WET SNOW OVER THE INTERIOR E DURING
THE LATE AFTN. LOW CLOUDS AND FOG WERE PRESENT EARLY TODAY BEHIND
THE PCPN AREA IN MN...AND WILL PROBABLY SEE SOME OF THAT AND PERHAPS
SOME -DZ IN MAINLY AREAS THAT SEE UPSLOPING WITH A W WIND FOR A FEW
HRS AFTER PCPN ENDS AND BEFORE THE ONSET OF CAA OVERNIGHT INCREASES
LOW-LEVEL MIXING. BY 12Z...850MB TEMPS ARE PROGGED AT -8/-9C OVER
WRN LAKE SUPERIOR. WHILE THAT IS SHY OF THE THRESHOLD FOR LES GIVEN
WATER TEMPS AROUND 1C...SRN EDGE OF DEEP LAYER FORCING ASSOCIATED
WITH APPROACHING SHORTWAVE AND PRESENCE OF CYCLONIC FLOW MAY
GENERATE SOME LAKE ENHANCED -SHSN OVER NW UPPER MI LATE IN THE
NIGHT.
DURING THE DAY SUN...SHORTWAVE DIGS S ACROSS THE UPPER GREAT
LAKES...BRINGING 100-120M HEIGHT FALLS AT 500MB. ALTHOUGH BEST DEEP
LAYER FORCING PASSES N AND NE OF UPPER MI...DEEP CYCLONIC FLOW AND
SUFFICIENT INCREASE IN MOISTURE DEPTH TO AROUND 10KFT SUGGESTS SCT
TO NMRS -SHSN ARE A GOOD BET. LATE MAR SOLAR INSOLATION WILL ADD A
DIURNAL COMPONENT TO -SHSN COVERAGE OVER THE INTERIOR WHILE
DISRUPTING NORMAL LAKE EFFECT PROCESSES THAT WOULD BE GETTING
UNDERWAY OVER LAKE SUPERIOR AS 850MB TEMPS FALL TOWARD -14C IN THE
AFTN. ALTHOUGH COLUMN BECOMES MORE SUPPORTIVE OF SNOW AS PTYPE AS
THE DAY PROGRESSES...DAYTIME HEATING SHOULD RESULT IN MIX WITH -SHRA
INTO THE MID AFTN OVER THE SCNTRL. WINDS MAY APPROACH ADVY CRITERIA
OVER THE KEWEENAW...BUT WITH MIXED LAYER WINDS LOW/MID 30KT AT MOST
AND ONLY MODEST PRES RISES APPROACHING FROM THE NW...DO NOT
ANTICIPATE WIND ADVY BEING NEEDED AT THIS POINT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 453 PM EDT SAT MAR 30 2013
CONTINUE TO SEE GOOD AGREEMENT FROM GFS/ECMWF/GEM-NH IN OVERALL
LARGER SCALE PATTERN FOR THE LONG TERM. DEEP AND COLD TROUGHING
INITIALLY IN PLACE LEADS TO A PERIOD OF LAKE ENHANCED SNOW FOR
SNOWBELTS FAVORED BY NORTHWEST WINDS SUNDAY NIGHT THROUGH TUESDAY
MORNING. FOCUSED IN ON MORE OF THE DETAILS THIS GO AROUND. WAVE
THAT MOVES THROUGH TO BRING IN THE TROUGHING ON SUNDAY NIGHT PRETTY
SHARP UPSTREAM THIS MORNING OVER NORTHERN MANITOBA INTO NINAVUT.
WENT WITH MODELS THAT WERE SHARPER WITH H5 WAVE AND RESULTING SFC
TROUGH DROPPING ACROSS LK SUPERIOR LATE SUNDAY AFTN INTO SUNDAY
EVENING. SOUNDINGS DURING THAT TIME INDICATE MORE OF A WIDESPREAD
SNOW JUST IN WAKE OF FRONT...ALONG WITH PUSH OF NORTH WINDS TO AROUND
40 MPH. EXPANDED POPS OVER MUCH OF THE NORTH HALF OF CWA SUNDAY
EVENING. SNOWFALL RATES MAY EXCEED 1"/HOUR FOR A COUPLE HOURS AS
THIS BAND OF SNOW MOVES THROUGH. BY MIDNIGHT...MODELS INDICATE
WIDESPREAD DEEPER H8-H7 MOISTURE DEPARTS LEAVING MOST OF THE SNOW
SET UP OVER HIGHER TERRAIN OF WEST AND NCNTRL CWA AND ALSO FOR
SNOWBELTS FROM MUNISING TO NEWBERRY.
LAKE ENHANCED SNOW THAT OCCURS FOR THOSE SNOWBELTS LATER SUNDAY
NIGHT INTO MONDAY MAY BE HEAVY AT TIMES AS SOUNDINGS INDICATE
MOISTURE THROUGH H8 AND INVERSION HEIGHTS UP TO 10KFT. OVER-WATER
INSTABILITY IS SUFFICIENT AS H85 TEMPS ARE AROUND -16C. AT FIRST
GLANCE SEEMS LIKE LAKE EFFECT SNOW WATCH MAY BE IN ORDER. THERE ARE
A COUPLE NEGATIVE FACTORS THOUGH THAT PROHIBITED ISSUANCE OF WATCH.
FIRST OF WHICH IS DRYING NOTED BLO 5KFT LEADING TO MORE OF AN
INVERTED-V LOOK TO SOUNDING...ESPECIALLY OVERNIGHT SUNDAY NIGHT INTO
MONDAY. SECOND NEGATIVE IS SHEAR IN THE MOIST CONVECTIVE LAYER AT
LEAST TO START OUT...BUT THIS DOES EASE LATE SUNDAY NIGHT THOUGH BLYR
WINDS STAY UP TO 30 KTS FROM THE NORTHWEST. BEST SHOT AT HEAVIER SNOW
WOULD BE THROUGH MID-LATE MORNING ON MONDAY AS DAYTIME HEATING/HIGHER
SUN ANGLE WILL ACT TO DISRUPT SNOW SHOWERS AS THE DAY GOES ON. LAKE
EFFECT SNOW SHOWERS MAY INCREASE AGAIN MONDAY NIGHT. DUE TO COMBO OF
THE LAKE EFFECT SNOWS AND BLOWING SNOW...LIKELY WILL NEED ADVISORY
HEADLINES INTO MONDAY NIGHT AND TUESDAY MORNING.
SINCE THERE IS NOT MUCH BLOCKINESS DOWNSTREAM...DEEP TROUGH WILL REMAIN
PROGRESSIVE WITH RISING HEIGHTS DEVELOPING OVER UPPER LAKES AS EARLY
AS TUESDAY. SUFFICIENTLY COLD AND MOIST ENOUGH FOR LK EFFECT BUT
LARGER SCALE NEGATIVES SHOULD RESULT IN DIMINISHING TREND TO LK
EFFECT BY TUESDAY AFTN. POPS REFLECTED THIS FOR MOST PART...JUST
NEEDED SOME MINOR TWEAKS.
AFTER PARTIAL CLEARING AND WARMER CONDITIONS FOR WEDNESDAY ANOTHER
SHORTWAVE TROUGH THEN SWINGS ACROSS MANITOBA AND NORTHERN ONTARIO
WEDNESDAY NIGHT AND THURSDAY. ASSOCIATED COLD FRONT MOVES ACROSS
UPPER LAKES ON THURSDAY. DPROG/DT FROM EARLIER GFS/ECMWF RUNS
INDICATED A SLOWER TREND WITH SHORTWAVE POINTING TO MOST OF
PRECIPITATION FROM THE SYSTEM TAKING PLACE ON THURSDAY OVER UPPER
MICHIGAN. 12Z GFS REALLY SPED UP AND SEEMS OUT OF PLACE NOW WITH
PCPN TIMING. 1000-500MB AND 1000-850MB THICKNESSES INDICATE MIX OF
RAIN/SNOW. LIMITED MOISTURE WILL KEEP AMOUNTS LIGHT. COOLER AND DRY
IN WAKE OF COLD FRONT INTO FRIDAY.
QUESTIONS INCREASE FOR NEXT WEEKEND. GOOD BET THAT UPPER LAKES WILL
BE ON THE SOUTHERN EDGE OF STRONGER JET STREAM RIDING ALONG SOUTHERN
TIER OF CANADA. AS MID-LEVEL FLOW BECOMES MORE WESTERLY MODELS
INDICATE SHORTWAVE TROUGH AND SFC-H85 LOWS VCNTY OF NORTHERN PLAINS
INTO WESTERN GREAT LAKES BY 12Z SATURDAY. POOR CONSISTENCY ON WHERE
SFC-H85 LOWS SET UP THOUGH. LATEST ECMWF/GFS CONTINUE TO INDICATE
FARTHER NORTH LOW WITH QPF INTO UPPER LAKES BY NEXT SATURDAY WHILE
EARLIER RUNS KEPT MOST OF QPF TO SOUTH. 1000-500MB AND 1000-850MB
THICKNESSES AT OR ABOVE 540DAM AND 1305M AND H85 TEMPS OVER 0C INTO
WESTERN CWA INDICATE MIX OF RAIN AND SNOW. CONSENSUS OF MODELS CAME
UP WITH HIGHER CHANCE POPS WHICH WILL WORK IF THE NORTHERN TREND
CONTINUES IN THE MODELS. JUST CANNOT SEEM TO SHAKE THIS COOLER AND
ACTIVE WEATHER PATTERN AS WE HEAD INTO THE FIRST WEEK OF APRIL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 808 PM EDT SAT MAR 30 2013
AREA OF PCPN ASSOCIATED WITH LOW PRES TROF HAS SHIFTED E OF THE TAF
SITES. PER SATELLITE IMAGERY AND PER SFC OBS DRIER AIR ADVECTING IN
BEHIND TROUGH HAS ERODED LOW CLOUDS AND FOG OVER KIWD AND KCMX WHERE
CONDITIONS SHOULD BE VFR AND MVFR FOR A TIME THIS EVENING
RESPECTIVELY. DRIER AIR WILL BE SLOWER TO REACH KSAW WHERE LIFR
CONDITIONS WILL SLOWLY IMPROVE TO IFR LATE THIS EVENING/OVERNIGHT.
APPROACH OF NEXT DISTURBANCE WILL BRING A RETURN TO MVFR CONDITIONS
AT KIWD OVERNIGHT. EXPECT INCREASING POTENTIAL OF -SHSN AND CONTINUED
MVFR CONDITIONS AT KIWD/KCMX LATE TONIGHT INTO SUNDAY AS DISTURBANCE
ARRIVES. GUSTY WNW WINDS WILL DEVELOP FOLLOWING NEXT SFC TROF PASSAGE
LATE MORNING. AT KSAW...ONSET OF WESTERLY WIND WILL FAVOR DOWNSLOPE
DRYING AFT 12Z SUNDAY SO EXPECT CIGS TO IMPROVE TO MVFR AT THAT
TIME. WNW AND COLD ADVECTION BEHIND FRONT WILL BRING A CHANCE OF
-SHSN SUNDAY AFTERNOON AT KSAW. &&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 453 PM EDT SAT MAR 30 2013
STRONGER DISTURBANCE MOVING INTO THE UPPER LAKES SUN WILL USHER
COLDER AIR OVER LAKE SUPERIOR WHILE SFC LOW PRES DEEPENS TO THE E
AND NE. THIS WILL RESULT IN STRENGTHENING NW WINDS ACROSS THE LAKE.
IN FACT...NW GALES ARE EXPECTED TO DEVELOP OVER CNTRL AND ERN LAKE
SUPERIOR SUN AFTN. UNDER SLOW MOVING WEATHER PATTERN WITH COLD
UNSTABLE AIR OVER THE LAKE...THE GALES WILL LIKELY CONTINUE INTO
TUE. FREEZING SPRAY WILL ALSO DEVELOP SUN NIGHT AND LINGER INTO TUE
AS UNSEASONABLY COLD AIR SETTLES OVER THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 2 PM SUNDAY TO 8 PM EDT TUESDAY FOR LSZ264>267.
GALE WARNING FROM 2 PM SUNDAY TO 6 PM EDT MONDAY FOR LSZ244-245-
249>251.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...VOSS
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS GAYLORD MI
130 PM EDT FRI MAR 29 2013
.SYNOPSIS...
ISSUED AT 329 AM EDT FRI MAR 29 2013
HIGH PRESSURE WILL ADVANCE FROM THE UPPER MIDWEST THROUGH THE GREAT
LAKES TO ROUND OUT TODAY. THIS PATTERN WILL BRING SUNSHINE THROUGH
THE FIRST HALF OF SATURDAY. TEMPERATURES WILL ALSO FINALLY...ALTHOUGH
BRIEFLY...WARM ABOVE NORMAL FOR THE FIRST HALF OF THE WEEKEND.
THAT TREND WILL BE SHORT LIVED...AS A STRONG COLD FRONT ARRIVES
SATURDAY NIGHT...WITH A ROUND OF RAIN OR SNOW SHOWERS LIKELY. AS
THE FRONT PASSES...MUCH COLDER WEATHER WILL ARRIVE LATER SUNDAY
AND STICK AROUND THROUGH AT LEAST TUESDAY...WITH PERIODIC LAKE
EFFECT SNOW SHOWERS AND WINDY CONDITIONS.
&&
.UPDATE...
ISSUED AT 129 PM EDT FRI MAR 29 2013
STRATUS IS GONE OVER EASTERN UPPER. A FEW CU HAVE FIRED SOUTH OF
CAD/HTL...AND INLAND OF OSC/TAWAS...OTHERWISE SKIES ARE CLEAR.
OSC BRIEFLY TWEAKED UP TO 47F...BUT A LAKE BREEZE HAS BROUGHT THEM
BACK TO EARTH. MOST SITES NEAR 40S TO THE MID 40S...SOME OF THE MORE
MARITIME LOCALES STILL STUCK IN THE 30S. NO MAJOR CHANGES MADE.
UPDATE ISSUED AT 959 AM EDT FRI MAR 29 2013
PATCHY STRATUS CONTINUES IN EASTERN CHIPPEWA CO AND OVER WHITEFISH
BAY...THOUGH HAS BROKEN UP SOMEWHAT OVER THE SAULTS PROPER.
THE STRATUS SHOULD ERODE AND MIX OUT OVER THE NEXT 3 HOURS. TEMPS
HAVE REBOUNDED INTO THE MID 20S TO MID 30S...DO NOT PLAN ON ANY
SIGNIFICANT CHANGES TO THE MAX TEMP FORECAST.
UPDATE ISSUED AT 613 AM EDT FRI MAR 29 2013
CHANGES THIS HOUR: COULDN/T QUITE GET THROUGH THE OVERNIGHT
WITHOUT DEALING WITH SOME STRATUS. A PATCH HAS POPPED UP OVER THE
PAST HOUR FROM KANJ NORTH INTO THE HIGH TERRAIN EAST OF WHITEFISH
BAY ACROSS THE BORDER IN ONTARIO. NEAR TERM RUC PROGS SUGGEST THAT
SOMEWHAT ENHANCED H9 MOISTURE FROM THIS AREA EAST WILL MOVE EAST
AND AWAY FROM THE REGION THIS MORNING. DON/T EXPECT THIS TO GET
TOO OUT OF HAND/WIDESPREAD...BUT WILL CARRY SOME ADDITIONAL
CLOUDINESS THROUGH THE NEXT FEW HOURS AS EARLY MORNING INVERSION
WILL ALLOW ANYTHING THAT DEVELOPS TO PERSIST FOR A TIME.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 329 AM EDT FRI MAR 29 2013
HIGH IMPACT WEATHER POTENTIAL: NONE.
OVERVIEW: EARLY MORNING WATER VAPOR IMAGERY REVEALS RECENT BLOCKING
OVER EASTERN CANADA RETREATING EAST AS BROAD NORTHWEST FLOW BEGINS
TO TAKE OVER ALOFT ACROSS THE GREAT LAKES REGION. THE CLOSED HIGH
ASSOCIATED WITH THIS BLOCK HAS OPENED UP...AND WAS OVERHEAD AS
SHORTWAVE RIDGING YESTERDAY AND HAS NOW PUSHED INTO THE NORTHEASTERN
CONUS AS OF THIS MORNING. MOVING DOWN TO THE SURFACE...A MODEST
SURFACE RIDGE AXIS IS DRAPED FROM JUST WEST OF THE WESTERN LAKES
INTO INDIANA/KENTUCKY...WHICH HAS PROVIDED CALM/QUIET WEATHER ACROSS
THE GREAT LAKES REGION. 00Z APX RAOB SHOWED -4C AT H8...JUST ABOUT
NORMAL FOR THIS TIME OF YEAR WITH OUR AVERAGE TEMPERATURE FOR THE
DATE YESTERDAY SIMILARLY CLOSE TO NORMAL. WITH THIS HIGH OVERHEAD
AND THE MAJORITY OF ANY JET ENERGY RESIDING OVER THE SOUTHEASTERN
STATES...THE WEATHER LOOKS QUIET THROUGH THE SHORT TERM PORTION OF
THE FORECAST...BUT THE AFOREMENTIONED BREAKING DOWN OF THE BLOCK
OVER CANADA PORTENDS THAT THIS QUIET STRETCH OF WEATHER WILL BE
COMING TO AN END SOON...SO DON/T GET USED TO WHAT YOU SEE TODAY!
THROUGH DAYBREAK: TERRIFIC RADIATIONAL COOLING CONDITIONS ALLOWING
SOME SPOTS TO REACH 20F AS OF THIS WRITING...WITH A WEAK WIND
KEEPING SOME HIGHER TERRAIN SPOTS AS WELL AS THE NE LOWER COAST IN
THE UPPER 20S TO AROUND 30 UNDER CLEAR SKIES. LITTLE CHANGE THROUGH
DAYBREAK...WITH SOME LOCAL SLICK SPOTS LIKELY AS AFTERNOON PUDDLES
REFREEZE.
TODAY: WEAK SHORTWAVE TROUGH NOW EXITING TO THE SOUTHEAST OF THE
REGION WILL ALLOW FOR GRADUALLY BUILDING MID LEVEL HEIGHTS /ALONG
WITH MID LEVEL NVA/ TODAY WITH THE RIDGE OF SURFACE HIGH PRESSURE
SLIDING EAST INTO THE REGION. LLEVEL TRAJECTORIES SHOW TODAY/S
AIRMASS ARRIVING FROM WESTERN ONTARIO 24 HOURS PREVIOUSLY...AND A
LOOK AT YESTERDAY/S CONDITIONS THERE SHOW NO CUMULUS DEVELOPMENT
/DEWPOINTS FALLING INTO THE LOWER-MID TEENS/ ALONG WITH LOWER 40S
FOR HIGHS. GIVEN THE OVERHEAD HIGH PRESSURE AND NVA...WILL ALLOW
FOR SOME WARMING TO THIS AIRMASS THROUGH SUBSIDENCE WHICH SUGGESTS
TRENDING TOWARDS THE WARMER ECMWF-MOS GUIDANCE TODAY...YIELDING
HIGHS IN THE MID-UPPER 40S MOST LOCATIONS UNDER SUNNY SKIES...
WARMEST SOUTHEASTERN AREAS WHERE LAKE INFLUENCE ON TEMPS WILL BE
LESS.
TONIGHT: HIGH PRESSURE SETTLES OVERHEAD WITH SHORT-WAVE RIDGING
CONTINUING/SHARPENING AT MID LEVELS IN RESPONSE TO OUR NEXT WEATHER
MAKER DROPPING SOUTH OUT OF CENTRAL CANADA. THIS WILL LIKELY SPREAD
SOME HIGH CLOUDINESS INTO THE REGION AFTER MIDNIGHT...BUT FOR THE
MOST PART EXPECT ANOTHER CALM/CLEAR/QUIET NIGHT WITH TERRIFIC
RADIATIONAL COOLING CONDITIONS YET AGAIN. AFTERNOON CROSSOVER TEMPS
WILL LIKELY BE IN THE LOWER-MIDDLE TEENS...SO LOWS SHOULD HAVE NO
PROBLEM FALLING INTO THE MIDDLE-UPPER TEENS IN THE COLD SPOTS YET
AGAIN WITH LOWS GENERALLY IN THE LOWER 20S ELSEWHERE.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 329 AM EDT FRI MAR 29 2013
SATURDAY...AS THE SFC HIGH MOVES EAST, THE COLD FRONT FROM THE WEST
BEARS DOWN ON THE FORECAST AREA. AIDING THE COLD FRONT IS THE 500 MB
SHORTWAVE TROUGH THAT IS CHASING THE RIDGE EAST AS WELL. THE MORNING
LOOKS TO REMAIN DRY AS THE MOISTURE AT 850 MB AND IN THE 700-500 MB
LAYER TAKES UNTIL AROUND 18Z TO BEGIN GETTING MOIST ENOUGH TO
SUPPORT PRECIPITATION. THE PROFILE WOULD SUGGEST THAT THE
PRECIPITATION WOULD BE ALL RAIN THROUGH 00Z.
SATURDAY NIGHT...MOISTURE CONTINUES OVER THE REGION AND THE PROFILES
BEGIN TO MOVE TOWARD 0C SO THAT THERE WILL BE A MIX IN E UPPER AND
PROBABLY RAIN IN N LOWER. THE PROFILES DON`T CHANGE MUCH OVERNIGHT
SO THAT A MIX IS WHAT WILL BE EXPECTED. ALSO, THE 700-500 MB LAYER
BEGINS TO DRY OUT SIGNIFICANTLY ENOUGH THAT IT MAY STOP
PRECIPITATING. SO WILL GO WITH THE CHANCE POPS IN E UPPER AND OVER
LAKE MICHIGAN. STILL LOTS OF MOISTURE OVER N LOWER AND LAKE HURON TO
CONTINUE THE LIKELY POPS.
SUNDAY...THE MOISTURE CONTINUES TO MOVE EAST, WITH COLD AIR SPILLING
INTO THE FORECAST AREA. AS THE COLD AIR MOVES IN THE MOISTURE
BEGINS TO MOVE INTO THE REGION WITH SATURATION REACHING -10C. THIS
GETS THE LIGHT SNOW/FLURRIES STARTED AS THE STABILITY BEGINS TO
DECREASE AND UNDER THE 500 MB LOW AND SHORTWAVES ROTATING AROUND
IT. OVERNIGHT, THE 850 MB TEMPERATURES FALL TO AROUND -13C ON THE
ECMWF BY 12Z. THE GFS IS SIGNIFICANTLY COLDER (-17C) AND WOULD
PRODUCE LES FAIRLY WELL WITH THE 500 MB LOW. WILL HEDGE
PESSIMISTIC AS THIS SEASON HAS REMAINED COLDER THAN FIRST THOUGHT.
EXTENDED (MONDAY THROUGH THURSDAY)...MONDAY, LOOKS LIKE THE
TEMPERATURES FALL ENOUGH TO HAVE LES ON BOTH MODELS AS THE ECMWF HAS
-14C AT 850 MB BY 00Z. EARLIER IN THE WEEK, THE WINDS LOOKED
STRONGER, NOW IT LOOKS BREEZY. WILL CONTINUE THE GUSTY WINDS IN THE
HWO. TUESDAY, AS THE SFC HIGH BEGINS TO MOVE INTO THE REGION, THE
850 MB TEMPERATURES BEGIN TO WARM SLIGHTLY, JUST ENOUGH THAT WE MAY
LOSE THE INSTABILITY NEEDED FOR THE LES. THIS CONTINUES INTO THE
NIGHT SO WOULD EXPECT THAT THE SNOW WOULD STOP. 00Z ECMWF SAYS
THAT IT SHOULD. WEDNESDAY, HIGH PRESSURE AT THE SFC AND 500 MB
RIDGE MOVES THROUGH THE REGION SO THAT WE WILL REMAIN DRY FOR THE
DAY. OVERNIGHT, THE ANOTHER COLD FRONT AND 500 MB SHORTWAVE TROUGH
MOVE THROUGH THE REGION. ONE SOLUTION IS WARM ENOUGH FOR RAIN AND
ONE COLD ENOUGH FOR SNOW. SO WILL GO WITH A MIX AT THIS POINT.
THURSDAY, THINK THAT THE GFS IS A LITTLE TOO WET AT 850 MB AND
THINK THAT THE THE ECMWF HAS THE RIGHT IDEA, THAT IS IT IS IN LINE
WITH THE CURRENT FORECAST SO WILL CONTINUE THE DRY DAY AND NIGHT
AT HIGH PRESSURE BEGINS TO BUILD INTO THE REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 129 PM EDT FRI MAR 29 2013
VFR. CLOUDS INCREASING ON SATURDAY.
HIGH PRESSURE OVER THE PRESSURE PROVIDING NEARLY CLEAR SKIES THIS
AFTERNOON AND MOST OF TONIGHT. THE HIGH MOVES EAST TONIGHT AND
MORE RAPIDLY SO ON SATURDAY...ALLOWING CLOUDS TO FILTER IN FROM
THE WEST. ANY PRECIP THREAT WILL WAIT UNTIL AFTER 18Z SATURDAY.
LIGHT NW WINDS TODAY...INTERRUPTED BY LAKE BREEZES. LIGHT WINDS
TONIGHT...SOUTHERLY WINDS SATURDAY.
&&
.MARINE...
ISSUED AT 329 AM EDT FRI MAR 29 2013
SUMMARY: HIGH PRESSURE WILL REMAIN IN CONTROL OF THE REGION/S
WEATHER THROUGH SATURDAY WITH QUIET CONDITIONS OVER THE LAKES. A
COLD FRONT WILL APPROACH SUNDAY...BRINGING STRENGTHENING SOUTHERLY
WINDS. IN IT/S WAKE...NORTHWEST WINDS WILL DEVELOP AND STRENGTHEN
SUNDAY NIGHT INTO MONDAY WITH STRONG WINDS CONTINUING THROUGH
TUESDAY BEFORE HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION FROM
THE WEST.
HEADLINE POTENTIAL: SMALL CRAFT POTENTIAL UNDER SOUTHERLY FLOW
SATURDAY WITH A PROLONGED PERIOD OF SMALL CRAFT WINDS DEVELOPING
BEHIND A STRONG COLD FRONT SUNDAY NIGHT AND CONTINUING THROUGH NEXT
TUESDAY. THERE IS SOME POTENTIAL FOR LOW-END GALE FORCE WINDS IN
THE MONDAY-TUESDAY TIMEFRAME FOR NW FLOW FAVORED AREAS /NEAR
WHITEFISH POINT AND ALONG THE LAKE HURON COAST FROM THE BRIDGE
SOUTHEAST TO PRESQUE ISLE LIGHT/.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JZ
SYNOPSIS...JL
SHORT TERM...ARNOTT
LONG TERM...JL
AVIATION...JZ
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS GAYLORD MI
959 AM EDT FRI MAR 29 2013
.SYNOPSIS...
ISSUED AT 329 AM EDT FRI MAR 29 2013
HIGH PRESSURE WILL ADVANCE FROM THE UPPER MIDWEST THROUGH THE GREAT
LAKES TO ROUND OUT TODAY. THIS PATTERN WILL BRING SUNSHINE THROUGH
THE FIRST HALF OF SATURDAY. TEMPERATURES WILL ALSO FINALLY...ALTHOUGH
BRIEFLY...WARM ABOVE NORMAL FOR THE FIRST HALF OF THE WEEKEND.
THAT TREND WILL BE SHORT LIVED...AS A STRONG COLD FRONT ARRIVES
SATURDAY NIGHT...WITH A ROUND OF RAIN OR SNOW SHOWERS LIKELY. AS
THE FRONT PASSES...MUCH COLDER WEATHER WILL ARRIVE LATER SUNDAY
AND STICK AROUND THROUGH AT LEAST TUESDAY...WITH PERIODIC LAKE
EFFECT SNOW SHOWERS AND WINDY CONDITIONS.
&&
.UPDATE...
ISSUED AT 959 AM EDT FRI MAR 29 2013
PATCHY STRATUS CONTINUES IN EASTERN CHIPPEWA CO AND OVER WHITEFISH
BAY...THOUGH HAS BROKEN UP SOMEWHAT OVER THE SAULTS PROPER.
THE STRATUS SHOULD ERODE AND MIX OUT OVER THE NEXT 3 HOURS. TEMPS
HAVE REBOUNDED INTO THE MID 20S TO MID 30S...DO NOT PLAN ON ANY
SIGNIFICANT CHANGES TO THE MAX TEMP FORECAST.
UPDATE ISSUED AT 613 AM EDT FRI MAR 29 2013
CHANGES THIS HOUR: COULDN/T QUITE GET THROUGH THE OVERNIGHT
WITHOUT DEALING WITH SOME STRATUS. A PATCH HAS POPPED UP OVER THE
PAST HOUR FROM KANJ NORTH INTO THE HIGH TERRAIN EAST OF WHITEFISH
BAY ACROSS THE BORDER IN ONTARIO. NEAR TERM RUC PROGS SUGGEST THAT
SOMEWHAT ENHANCED H9 MOISTURE FROM THIS AREA EAST WILL MOVE EAST
AND AWAY FROM THE REGION THIS MORNING. DON/T EXPECT THIS TO GET
TOO OUT OF HAND/WIDESPREAD...BUT WILL CARRY SOME ADDITIONAL
CLOUDINESS THROUGH THE NEXT FEW HOURS AS EARLY MORNING INVERSION
WILL ALLOW ANYTHING THAT DEVELOPS TO PERSIST FOR A TIME.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 329 AM EDT FRI MAR 29 2013
HIGH IMPACT WEATHER POTENTIAL: NONE.
OVERVIEW: EARLY MORNING WATER VAPOR IMAGERY REVEALS RECENT BLOCKING
OVER EASTERN CANADA RETREATING EAST AS BROAD NORTHWEST FLOW BEGINS
TO TAKE OVER ALOFT ACROSS THE GREAT LAKES REGION. THE CLOSED HIGH
ASSOCIATED WITH THIS BLOCK HAS OPENED UP...AND WAS OVERHEAD AS
SHORTWAVE RIDGING YESTERDAY AND HAS NOW PUSHED INTO THE NORTHEASTERN
CONUS AS OF THIS MORNING. MOVING DOWN TO THE SURFACE...A MODEST
SURFACE RIDGE AXIS IS DRAPED FROM JUST WEST OF THE WESTERN LAKES
INTO INDIANA/KENTUCKY...WHICH HAS PROVIDED CALM/QUIET WEATHER ACROSS
THE GREAT LAKES REGION. 00Z APX RAOB SHOWED -4C AT H8...JUST ABOUT
NORMAL FOR THIS TIME OF YEAR WITH OUR AVERAGE TEMPERATURE FOR THE
DATE YESTERDAY SIMILARLY CLOSE TO NORMAL. WITH THIS HIGH OVERHEAD
AND THE MAJORITY OF ANY JET ENERGY RESIDING OVER THE SOUTHEASTERN
STATES...THE WEATHER LOOKS QUIET THROUGH THE SHORT TERM PORTION OF
THE FORECAST...BUT THE AFOREMENTIONED BREAKING DOWN OF THE BLOCK
OVER CANADA PORTENDS THAT THIS QUIET STRETCH OF WEATHER WILL BE
COMING TO AN END SOON...SO DON/T GET USED TO WHAT YOU SEE TODAY!
THROUGH DAYBREAK: TERRIFIC RADIATIONAL COOLING CONDITIONS ALLOWING
SOME SPOTS TO REACH 20F AS OF THIS WRITING...WITH A WEAK WIND
KEEPING SOME HIGHER TERRAIN SPOTS AS WELL AS THE NE LOWER COAST IN
THE UPPER 20S TO AROUND 30 UNDER CLEAR SKIES. LITTLE CHANGE THROUGH
DAYBREAK...WITH SOME LOCAL SLICK SPOTS LIKELY AS AFTERNOON PUDDLES
REFREEZE.
TODAY: WEAK SHORTWAVE TROUGH NOW EXITING TO THE SOUTHEAST OF THE
REGION WILL ALLOW FOR GRADUALLY BUILDING MID LEVEL HEIGHTS /ALONG
WITH MID LEVEL NVA/ TODAY WITH THE RIDGE OF SURFACE HIGH PRESSURE
SLIDING EAST INTO THE REGION. LLEVEL TRAJECTORIES SHOW TODAY/S
AIRMASS ARRIVING FROM WESTERN ONTARIO 24 HOURS PREVIOUSLY...AND A
LOOK AT YESTERDAY/S CONDITIONS THERE SHOW NO CUMULUS DEVELOPMENT
/DEWPOINTS FALLING INTO THE LOWER-MID TEENS/ ALONG WITH LOWER 40S
FOR HIGHS. GIVEN THE OVERHEAD HIGH PRESSURE AND NVA...WILL ALLOW
FOR SOME WARMING TO THIS AIRMASS THROUGH SUBSIDENCE WHICH SUGGESTS
TRENDING TOWARDS THE WARMER ECMWF-MOS GUIDANCE TODAY...YIELDING
HIGHS IN THE MID-UPPER 40S MOST LOCATIONS UNDER SUNNY SKIES...
WARMEST SOUTHEASTERN AREAS WHERE LAKE INFLUENCE ON TEMPS WILL BE
LESS.
TONIGHT: HIGH PRESSURE SETTLES OVERHEAD WITH SHORT-WAVE RIDGING
CONTINUING/SHARPENING AT MID LEVELS IN RESPONSE TO OUR NEXT WEATHER
MAKER DROPPING SOUTH OUT OF CENTRAL CANADA. THIS WILL LIKELY SPREAD
SOME HIGH CLOUDINESS INTO THE REGION AFTER MIDNIGHT...BUT FOR THE
MOST PART EXPECT ANOTHER CALM/CLEAR/QUIET NIGHT WITH TERRIFIC
RADIATIONAL COOLING CONDITIONS YET AGAIN. AFTERNOON CROSSOVER TEMPS
WILL LIKELY BE IN THE LOWER-MIDDLE TEENS...SO LOWS SHOULD HAVE NO
PROBLEM FALLING INTO THE MIDDLE-UPPER TEENS IN THE COLD SPOTS YET
AGAIN WITH LOWS GENERALLY IN THE LOWER 20S ELSEWHERE.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 329 AM EDT FRI MAR 29 2013
SATURDAY...AS THE SFC HIGH MOVES EAST, THE COLD FRONT FROM THE WEST
BEARS DOWN ON THE FORECAST AREA. AIDING THE COLD FRONT IS THE 500 MB
SHORTWAVE TROUGH THAT IS CHASING THE RIDGE EAST AS WELL. THE MORNING
LOOKS TO REMAIN DRY AS THE MOISTURE AT 850 MB AND IN THE 700-500 MB
LAYER TAKES UNTIL AROUND 18Z TO BEGIN GETTING MOIST ENOUGH TO
SUPPORT PRECIPITATION. THE PROFILE WOULD SUGGEST THAT THE
PRECIPITATION WOULD BE ALL RAIN THROUGH 00Z.
SATURDAY NIGHT...MOISTURE CONTINUES OVER THE REGION AND THE PROFILES
BEGIN TO MOVE TOWARD 0C SO THAT THERE WILL BE A MIX IN E UPPER AND
PROBABLY RAIN IN N LOWER. THE PROFILES DON`T CHANGE MUCH OVERNIGHT
SO THAT A MIX IS WHAT WILL BE EXPECTED. ALSO, THE 700-500 MB LAYER
BEGINS TO DRY OUT SIGNIFICANTLY ENOUGH THAT IT MAY STOP
PRECIPITATING. SO WILL GO WITH THE CHANCE POPS IN E UPPER AND OVER
LAKE MICHIGAN. STILL LOTS OF MOISTURE OVER N LOWER AND LAKE HURON TO
CONTINUE THE LIKELY POPS.
SUNDAY...THE MOISTURE CONTINUES TO MOVE EAST, WITH COLD AIR SPILLING
INTO THE FORECAST AREA. AS THE COLD AIR MOVES IN THE MOISTURE
BEGINS TO MOVE INTO THE REGION WITH SATURATION REACHING -10C. THIS
GETS THE LIGHT SNOW/FLURRIES STARTED AS THE STABILITY BEGINS TO
DECREASE AND UNDER THE 500 MB LOW AND SHORTWAVES ROTATING AROUND
IT. OVERNIGHT, THE 850 MB TEMPERATURES FALL TO AROUND -13C ON THE
ECMWF BY 12Z. THE GFS IS SIGNIFICANTLY COLDER (-17C) AND WOULD
PRODUCE LES FAIRLY WELL WITH THE 500 MB LOW. WILL HEDGE
PESSIMISTIC AS THIS SEASON HAS REMAINED COLDER THAN FIRST THOUGHT.
EXTENDED (MONDAY THROUGH THURSDAY)...MONDAY, LOOKS LIKE THE
TEMPERATURES FALL ENOUGH TO HAVE LES ON BOTH MODELS AS THE ECMWF HAS
-14C AT 850 MB BY 00Z. EARLIER IN THE WEEK, THE WINDS LOOKED
STRONGER, NOW IT LOOKS BREEZY. WILL CONTINUE THE GUSTY WINDS IN THE
HWO. TUESDAY, AS THE SFC HIGH BEGINS TO MOVE INTO THE REGION, THE
850 MB TEMPERATURES BEGIN TO WARM SLIGHTLY, JUST ENOUGH THAT WE MAY
LOSE THE INSTABILITY NEEDED FOR THE LES. THIS CONTINUES INTO THE
NIGHT SO WOULD EXPECT THAT THE SNOW WOULD STOP. 00Z ECMWF SAYS
THAT IT SHOULD. WEDNESDAY, HIGH PRESSURE AT THE SFC AND 500 MB
RIDGE MOVES THROUGH THE REGION SO THAT WE WILL REMAIN DRY FOR THE
DAY. OVERNIGHT, THE ANOTHER COLD FRONT AND 500 MB SHORTWAVE TROUGH
MOVE THROUGH THE REGION. ONE SOLUTION IS WARM ENOUGH FOR RAIN AND
ONE COLD ENOUGH FOR SNOW. SO WILL GO WITH A MIX AT THIS POINT.
THURSDAY, THINK THAT THE GFS IS A LITTLE TOO WET AT 850 MB AND
THINK THAT THE THE ECMWF HAS THE RIGHT IDEA, THAT IS IT IS IN LINE
WITH THE CURRENT FORECAST SO WILL CONTINUE THE DRY DAY AND NIGHT
AT HIGH PRESSURE BEGINS TO BUILD INTO THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 638 AM EDT FRI MAR 29 2013
SUMMARY: HIGH PRESSURE CENTERED JUST WEST OF THE WESTERN GREAT LAKES
WILL SHIFT EAST...MOVING OVERHEAD THROUGH MOST OF THE UPCOMING TAF
PERIOD...ALLOWING FOR CONTINUED GOOD FLYING CONDITIONS.
RESTRICTIONS: NONE EXPECTED THROUGH THE TAF PERIOD. CONFIDENCE
HIGH.
WINDS: CALM WINDS WILL BECOME NORTHWEST 5-10KTS BY MID-LATE MORNING
AND THROUGH THE AFTERNOON BEFORE RETURNING TO CALM TONIGHT. A
LAKE BREEZE MAY CAUSE THESE NORTHWEST WINDS TO DIE OFF/SHIFT WEAK
SOUTHEAST AT APN BY MID/LATE AFTERNOON.
&&
.MARINE...
ISSUED AT 329 AM EDT FRI MAR 29 2013
SUMMARY: HIGH PRESSURE WILL REMAIN IN CONTROL OF THE REGION/S
WEATHER THROUGH SATURDAY WITH QUIET CONDITIONS OVER THE LAKES. A
COLD FRONT WILL APPROACH SUNDAY...BRINGING STRENGTHENING SOUTHERLY
WINDS. IN IT/S WAKE...NORTHWEST WINDS WILL DEVELOP AND STRENGTHEN
SUNDAY NIGHT INTO MONDAY WITH STRONG WINDS CONTINUING THROUGH
TUESDAY BEFORE HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION FROM
THE WEST.
HEADLINE POTENTIAL: SMALL CRAFT POTENTIAL UNDER SOUTHERLY FLOW
SATURDAY WITH A PROLONGED PERIOD OF SMALL CRAFT WINDS DEVELOPING
BEHIND A STRONG COLD FRONT SUNDAY NIGHT AND CONTINUING THROUGH NEXT
TUESDAY. THERE IS SOME POTENTIAL FOR LOW-END GALE FORCE WINDS IN
THE MONDAY-TUESDAY TIMEFRAME FOR NW FLOW FAVORED AREAS /NEAR
WHITEFISH POINT AND ALONG THE LAKE HURON COAST FROM THE BRIDGE
SOUTHEAST TO PRESQUE ISLE LIGHT/.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JZ
SYNOPSIS...JL
SHORT TERM...ARNOTT
LONG TERM...JL
AVIATION...ARNOTT
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS GAYLORD MI
639 AM EDT FRI MAR 29 2013
.SYNOPSIS...
ISSUED AT 329 AM EDT FRI MAR 29 2013
HIGH PRESSURE WILL ADVANCE FROM THE UPPER MIDWEST THROUGH THE GREAT
LAKES TO ROUND OUT TODAY. THIS PATTERN WILL BRING SUNSHINE THROUGH
THE FIRST HALF OF SATURDAY. TEMPERATURES WILL ALSO FINALLY...ALTHOUGH
BRIEFLY...WARM ABOVE NORMAL FOR THE FIRST HALF OF THE WEEKEND.
THAT TREND WILL BE SHORT LIVED...AS A STRONG COLD FRONT ARRIVES
SATURDAY NIGHT...WITH A ROUND OF RAIN OR SNOW SHOWERS LIKELY. AS
THE FRONT PASSES...MUCH COLDER WEATHER WILL ARRIVE LATER SUNDAY
AND STICK AROUND THROUGH AT LEAST TUESDAY...WITH PERIODIC LAKE
EFFECT SNOW SHOWERS AND WINDY CONDITIONS.
&&
.UPDATE...
ISSUED AT 613 AM EDT FRI MAR 29 2013
CHANGES THIS HOUR: COULDN/T QUITE GET THROUGH THE OVERNIGHT
WITHOUT DEALING WITH SOME STRATUS. A PATCH HAS POPPED UP OVER THE
PAST HOUR FROM KANJ NORTH INTO THE HIGH TERRAIN EAST OF WHITEFISH
BAY ACROSS THE BORDER IN ONTARIO. NEAR TERM RUC PROGS SUGGEST THAT
SOMEWHAT ENHANCED H9 MOISTURE FROM THIS AREA EAST WILL MOVE EAST
AND AWAY FROM THE REGION THIS MORNING. DON/T EXPECT THIS TO GET
TOO OUT OF HAND/WIDESPREAD...BUT WILL CARRY SOME ADDITIONAL
CLOUDINESS THROUGH THE NEXT FEW HOURS AS EARLY MORNING INVERSION
WILL ALLOW ANYTHING THAT DEVELOPS TO PERSIST FOR A TIME.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 329 AM EDT FRI MAR 29 2013
HIGH IMPACT WEATHER POTENTIAL: NONE.
OVERVIEW: EARLY MORNING WATER VAPOR IMAGERY REVEALS RECENT BLOCKING
OVER EASTERN CANADA RETREATING EAST AS BROAD NORTHWEST FLOW BEGINS
TO TAKE OVER ALOFT ACROSS THE GREAT LAKES REGION. THE CLOSED HIGH
ASSOCIATED WITH THIS BLOCK HAS OPENED UP...AND WAS OVERHEAD AS
SHORTWAVE RIDGING YESTERDAY AND HAS NOW PUSHED INTO THE NORTHEASTERN
CONUS AS OF THIS MORNING. MOVING DOWN TO THE SURFACE...A MODEST
SURFACE RIDGE AXIS IS DRAPED FROM JUST WEST OF THE WESTERN LAKES
INTO INDIANA/KENTUCKY...WHICH HAS PROVIDED CALM/QUIET WEATHER ACROSS
THE GREAT LAKES REGION. 00Z APX RAOB SHOWED -4C AT H8...JUST ABOUT
NORMAL FOR THIS TIME OF YEAR WITH OUR AVERAGE TEMPERATURE FOR THE
DATE YESTERDAY SIMILARLY CLOSE TO NORMAL. WITH THIS HIGH OVERHEAD
AND THE MAJORITY OF ANY JET ENERGY RESIDING OVER THE SOUTHEASTERN
STATES...THE WEATHER LOOKS QUIET THROUGH THE SHORT TERM PORTION OF
THE FORECAST...BUT THE AFOREMENTIONED BREAKING DOWN OF THE BLOCK
OVER CANADA PORTENDS THAT THIS QUIET STRETCH OF WEATHER WILL BE
COMING TO AN END SOON...SO DON/T GET USED TO WHAT YOU SEE TODAY!
THROUGH DAYBREAK: TERRIFIC RADIATIONAL COOLING CONDITIONS ALLOWING
SOME SPOTS TO REACH 20F AS OF THIS WRITING...WITH A WEAK WIND
KEEPING SOME HIGHER TERRAIN SPOTS AS WELL AS THE NE LOWER COAST IN
THE UPPER 20S TO AROUND 30 UNDER CLEAR SKIES. LITTLE CHANGE THROUGH
DAYBREAK...WITH SOME LOCAL SLICK SPOTS LIKELY AS AFTERNOON PUDDLES
REFREEZE.
TODAY: WEAK SHORTWAVE TROUGH NOW EXITING TO THE SOUTHEAST OF THE
REGION WILL ALLOW FOR GRADUALLY BUILDING MID LEVEL HEIGHTS /ALONG
WITH MID LEVEL NVA/ TODAY WITH THE RIDGE OF SURFACE HIGH PRESSURE
SLIDING EAST INTO THE REGION. LLEVEL TRAJECTORIES SHOW TODAY/S
AIRMASS ARRIVING FROM WESTERN ONTARIO 24 HOURS PREVIOUSLY...AND A
LOOK AT YESTERDAY/S CONDITIONS THERE SHOW NO CUMULUS DEVELOPMENT
/DEWPOINTS FALLING INTO THE LOWER-MID TEENS/ ALONG WITH LOWER 40S
FOR HIGHS. GIVEN THE OVERHEAD HIGH PRESSURE AND NVA...WILL ALLOW
FOR SOME WARMING TO THIS AIRMASS THROUGH SUBSIDENCE WHICH SUGGESTS
TRENDING TOWARDS THE WARMER ECMWF-MOS GUIDANCE TODAY...YIELDING
HIGHS IN THE MID-UPPER 40S MOST LOCATIONS UNDER SUNNY SKIES...
WARMEST SOUTHEASTERN AREAS WHERE LAKE INFLUENCE ON TEMPS WILL BE
LESS.
TONIGHT: HIGH PRESSURE SETTLES OVERHEAD WITH SHORT-WAVE RIDGING
CONTINUING/SHARPENING AT MID LEVELS IN RESPONSE TO OUR NEXT WEATHER
MAKER DROPPING SOUTH OUT OF CENTRAL CANADA. THIS WILL LIKELY SPREAD
SOME HIGH CLOUDINESS INTO THE REGION AFTER MIDNIGHT...BUT FOR THE
MOST PART EXPECT ANOTHER CALM/CLEAR/QUIET NIGHT WITH TERRIFIC
RADIATIONAL COOLING CONDITIONS YET AGAIN. AFTERNOON CROSSOVER TEMPS
WILL LIKELY BE IN THE LOWER-MIDDLE TEENS...SO LOWS SHOULD HAVE NO
PROBLEM FALLING INTO THE MIDDLE-UPPER TEENS IN THE COLD SPOTS YET
AGAIN WITH LOWS GENERALLY IN THE LOWER 20S ELSEWHERE.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 329 AM EDT FRI MAR 29 2013
SATURDAY...AS THE SFC HIGH MOVES EAST, THE COLD FRONT FROM THE WEST
BEARS DOWN ON THE FORECAST AREA. AIDING THE COLD FRONT IS THE 500 MB
SHORTWAVE TROUGH THAT IS CHASING THE RIDGE EAST AS WELL. THE MORNING
LOOKS TO REMAIN DRY AS THE MOISTURE AT 850 MB AND IN THE 700-500 MB
LAYER TAKES UNTIL AROUND 18Z TO BEGIN GETTING MOIST ENOUGH TO
SUPPORT PRECIPITATION. THE PROFILE WOULD SUGGEST THAT THE
PRECIPITATION WOULD BE ALL RAIN THROUGH 00Z.
SATURDAY NIGHT...MOISTURE CONTINUES OVER THE REGION AND THE PROFILES
BEGIN TO MOVE TOWARD 0C SO THAT THERE WILL BE A MIX IN E UPPER AND
PROBABLY RAIN IN N LOWER. THE PROFILES DON`T CHANGE MUCH OVERNIGHT
SO THAT A MIX IS WHAT WILL BE EXPECTED. ALSO, THE 700-500 MB LAYER
BEGINS TO DRY OUT SIGNIFICANTLY ENOUGH THAT IT MAY STOP
PRECIPITATING. SO WILL GO WITH THE CHANCE POPS IN E UPPER AND OVER
LAKE MICHIGAN. STILL LOTS OF MOISTURE OVER N LOWER AND LAKE HURON TO
CONTINUE THE LIKELY POPS.
SUNDAY...THE MOISTURE CONTINUES TO MOVE EAST, WITH COLD AIR SPILLING
INTO THE FORECAST AREA. AS THE COLD AIR MOVES IN THE MOISTURE
BEGINS TO MOVE INTO THE REGION WITH SATURATION REACHING -10C. THIS
GETS THE LIGHT SNOW/FLURRIES STARTED AS THE STABILITY BEGINS TO
DECREASE AND UNDER THE 500 MB LOW AND SHORTWAVES ROTATING AROUND
IT. OVERNIGHT, THE 850 MB TEMPERATURES FALL TO AROUND -13C ON THE
ECMWF BY 12Z. THE GFS IS SIGNIFICANTLY COLDER (-17C) AND WOULD
PRODUCE LES FAIRLY WELL WITH THE 500 MB LOW. WILL HEDGE
PESSIMISTIC AS THIS SEASON HAS REMAINED COLDER THAN FIRST THOUGHT.
EXTENDED (MONDAY THROUGH THURSDAY)...MONDAY, LOOKS LIKE THE
TEMPERATURES FALL ENOUGH TO HAVE LES ON BOTH MODELS AS THE ECMWF HAS
-14C AT 850 MB BY 00Z. EARLIER IN THE WEEK, THE WINDS LOOKED
STRONGER, NOW IT LOOKS BREEZY. WILL CONTINUE THE GUSTY WINDS IN THE
HWO. TUESDAY, AS THE SFC HIGH BEGINS TO MOVE INTO THE REGION, THE
850 MB TEMPERATURES BEGIN TO WARM SLIGHTLY, JUST ENOUGH THAT WE MAY
LOSE THE INSTABILITY NEEDED FOR THE LES. THIS CONTINUES INTO THE
NIGHT SO WOULD EXPECT THAT THE SNOW WOULD STOP. 00Z ECMWF SAYS
THAT IT SHOULD. WEDNESDAY, HIGH PRESSURE AT THE SFC AND 500 MB
RIDGE MOVES THROUGH THE REGION SO THAT WE WILL REMAIN DRY FOR THE
DAY. OVERNIGHT, THE ANOTHER COLD FRONT AND 500 MB SHORTWAVE TROUGH
MOVE THROUGH THE REGION. ONE SOLUTION IS WARM ENOUGH FOR RAIN AND
ONE COLD ENOUGH FOR SNOW. SO WILL GO WITH A MIX AT THIS POINT.
THURSDAY, THINK THAT THE GFS IS A LITTLE TOO WET AT 850 MB AND
THINK THAT THE THE ECMWF HAS THE RIGHT IDEA, THAT IS IT IS IN LINE
WITH THE CURRENT FORECAST SO WILL CONTINUE THE DRY DAY AND NIGHT
AT HIGH PRESSURE BEGINS TO BUILD INTO THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 638 AM EDT FRI MAR 29 2013
SUMMARY: HIGH PRESSURE CENTERED JUST WEST OF THE WESTERN GREAT LAKES
WILL SHIFT EAST...MOVING OVERHEAD THROUGH MOST OF THE UPCOMING TAF
PERIOD...ALLOWING FOR CONTINUED GOOD FLYING CONDITIONS.
RESTRICTIONS: NONE EXPECTED THROUGH THE TAF PERIOD. CONFIDENCE
HIGH.
WINDS: CALM WINDS WILL BECOME NORTHWEST 5-10KTS BY MID-LATE MORNING
AND THROUGH THE AFTERNOON BEFORE RETURNING TO CALM TONIGHT. A
LAKE BREEZE MAY CAUSE THESE NORTHWEST WINDS TO DIE OFF/SHIFT WEAK
SOUTHEAST AT APN BY MID/LATE AFTERNOON.
&&
.MARINE...
ISSUED AT 329 AM EDT FRI MAR 29 2013
SUMMARY: HIGH PRESSURE WILL REMAIN IN CONTROL OF THE REGION/S
WEATHER THROUGH SATURDAY WITH QUIET CONDITIONS OVER THE LAKES. A
COLD FRONT WILL APPROACH SUNDAY...BRINGING STRENGTHENING SOUTHERLY
WINDS. IN IT/S WAKE...NORTHWEST WINDS WILL DEVELOP AND STRENGTHEN
SUNDAY NIGHT INTO MONDAY WITH STRONG WINDS CONTINUING THROUGH
TUESDAY BEFORE HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION FROM
THE WEST.
HEADLINE POTENTIAL: SMALL CRAFT POTENTIAL UNDER SOUTHERLY FLOW
SATURDAY WITH A PROLONGED PERIOD OF SMALL CRAFT WINDS DEVELOPING
BEHIND A STRONG COLD FRONT SUNDAY NIGHT AND CONTINUING THROUGH NEXT
TUESDAY. THERE IS SOME POTENTIAL FOR LOW-END GALE FORCE WINDS IN
THE MONDAY-TUESDAY TIMEFRAME FOR NW FLOW FAVORED AREAS /NEAR
WHITEFISH POINT AND ALONG THE LAKE HURON COAST FROM THE BRIDGE
SOUTHEAST TO PRESQUE ISLE LIGHT/.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...ARNOTT
SYNOPSIS...JL
SHORT TERM...ARNOTT
LONG TERM...JL
AVIATION...ARNOTT
MARINE...ARNOTT
AREA FORECAST DISCUSSION...UPDATED
NWS GAYLORD MI
619 AM EDT FRI MAR 29 2013
.SYNOPSIS...
ISSUED AT 329 AM EDT FRI MAR 29 2013
HIGH PRESSURE WILL ADVANCE FROM THE UPPER MIDWEST THROUGH THE GREAT
LAKES TO ROUND OUT TODAY. THIS PATTERN WILL BRING SUNSHINE THROUGH
THE FIRST HALF OF SATURDAY. TEMPERATURES WILL ALSO FINALLY...ALTHOUGH
BRIEFLY...WARM ABOVE NORMAL FOR THE FIRST HALF OF THE WEEKEND.
THAT TREND WILL BE SHORT LIVED...AS A STRONG COLD FRONT ARRIVES
SATURDAY NIGHT...WITH A ROUND OF RAIN OR SNOW SHOWERS LIKELY. AS
THE FRONT PASSES...MUCH COLDER WEATHER WILL ARRIVE LATER SUNDAY
AND STICK AROUND THROUGH AT LEAST TUESDAY...WITH PERIODIC LAKE
EFFECT SNOW SHOWERS AND WINDY CONDITIONS.
&&
.UPDATE...
ISSUED AT 613 AM EDT FRI MAR 29 2013
CHANGES THIS HOUR: COULDN/T QUITE GET THROUGH THE OVERNIGHT
WITHOUT DEALING WITH SOME STRATUS. A PATCH HAS POPPED UP OVER THE
PAST HOUR FROM KANJ NORTH INTO THE HIGH TERRAIN EAST OF WHITEFISH
BAY ACROSS THE BORDER IN ONTARIO. NEAR TERM RUC PROGS SUGGEST THAT
SOMEWHAT ENHANCED H9 MOISTURE FROM THIS AREA EAST WILL MOVE EAST
AND AWAY FROM THE REGION THIS MORNING. DON/T EXPECT THIS TO GET
TOO OUT OF HAND/WIDESPREAD...BUT WILL CARRY SOME ADDITIONAL
CLOUDINESS THROUGH THE NEXT FEW HOURS AS EARLY MORNING INVERSION
WILL ALLOW ANYTHING THAT DEVELOPS TO PERSIST FOR A TIME.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 329 AM EDT FRI MAR 29 2013
HIGH IMPACT WEATHER POTENTIAL: NONE.
OVERVIEW: EARLY MORNING WATER VAPOR IMAGERY REVEALS RECENT BLOCKING
OVER EASTERN CANADA RETREATING EAST AS BROAD NORTHWEST FLOW BEGINS
TO TAKE OVER ALOFT ACROSS THE GREAT LAKES REGION. THE CLOSED HIGH
ASSOCIATED WITH THIS BLOCK HAS OPENED UP...AND WAS OVERHEAD AS
SHORTWAVE RIDGING YESTERDAY AND HAS NOW PUSHED INTO THE NORTHEASTERN
CONUS AS OF THIS MORNING. MOVING DOWN TO THE SURFACE...A MODEST
SURFACE RIDGE AXIS IS DRAPED FROM JUST WEST OF THE WESTERN LAKES
INTO INDIANA/KENTUCKY...WHICH HAS PROVIDED CALM/QUIET WEATHER ACROSS
THE GREAT LAKES REGION. 00Z APX RAOB SHOWED -4C AT H8...JUST ABOUT
NORMAL FOR THIS TIME OF YEAR WITH OUR AVERAGE TEMPERATURE FOR THE
DATE YESTERDAY SIMILARLY CLOSE TO NORMAL. WITH THIS HIGH OVERHEAD
AND THE MAJORITY OF ANY JET ENERGY RESIDING OVER THE SOUTHEASTERN
STATES...THE WEATHER LOOKS QUIET THROUGH THE SHORT TERM PORTION OF
THE FORECAST...BUT THE AFOREMENTIONED BREAKING DOWN OF THE BLOCK
OVER CANADA PORTENDS THAT THIS QUIET STRETCH OF WEATHER WILL BE
COMING TO AN END SOON...SO DON/T GET USED TO WHAT YOU SEE TODAY!
THROUGH DAYBREAK: TERRIFIC RADIATIONAL COOLING CONDITIONS ALLOWING
SOME SPOTS TO REACH 20F AS OF THIS WRITING...WITH A WEAK WIND
KEEPING SOME HIGHER TERRAIN SPOTS AS WELL AS THE NE LOWER COAST IN
THE UPPER 20S TO AROUND 30 UNDER CLEAR SKIES. LITTLE CHANGE THROUGH
DAYBREAK...WITH SOME LOCAL SLICK SPOTS LIKELY AS AFTERNOON PUDDLES
REFREEZE.
TODAY: WEAK SHORTWAVE TROUGH NOW EXITING TO THE SOUTHEAST OF THE
REGION WILL ALLOW FOR GRADUALLY BUILDING MID LEVEL HEIGHTS /ALONG
WITH MID LEVEL NVA/ TODAY WITH THE RIDGE OF SURFACE HIGH PRESSURE
SLIDING EAST INTO THE REGION. LLEVEL TRAJECTORIES SHOW TODAY/S
AIRMASS ARRIVING FROM WESTERN ONTARIO 24 HOURS PREVIOUSLY...AND A
LOOK AT YESTERDAY/S CONDITIONS THERE SHOW NO CUMULUS DEVELOPMENT
/DEWPOINTS FALLING INTO THE LOWER-MID TEENS/ ALONG WITH LOWER 40S
FOR HIGHS. GIVEN THE OVERHEAD HIGH PRESSURE AND NVA...WILL ALLOW
FOR SOME WARMING TO THIS AIRMASS THROUGH SUBSIDENCE WHICH SUGGESTS
TRENDING TOWARDS THE WARMER ECMWF-MOS GUIDANCE TODAY...YIELDING
HIGHS IN THE MID-UPPER 40S MOST LOCATIONS UNDER SUNNY SKIES...
WARMEST SOUTHEASTERN AREAS WHERE LAKE INFLUENCE ON TEMPS WILL BE
LESS.
TONIGHT: HIGH PRESSURE SETTLES OVERHEAD WITH SHORT-WAVE RIDGING
CONTINUING/SHARPENING AT MID LEVELS IN RESPONSE TO OUR NEXT WEATHER
MAKER DROPPING SOUTH OUT OF CENTRAL CANADA. THIS WILL LIKELY SPREAD
SOME HIGH CLOUDINESS INTO THE REGION AFTER MIDNIGHT...BUT FOR THE
MOST PART EXPECT ANOTHER CALM/CLEAR/QUIET NIGHT WITH TERRIFIC
RADIATIONAL COOLING CONDITIONS YET AGAIN. AFTERNOON CROSSOVER TEMPS
WILL LIKELY BE IN THE LOWER-MIDDLE TEENS...SO LOWS SHOULD HAVE NO
PROBLEM FALLING INTO THE MIDDLE-UPPER TEENS IN THE COLD SPOTS YET
AGAIN WITH LOWS GENERALLY IN THE LOWER 20S ELSEWHERE.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 329 AM EDT FRI MAR 29 2013
SATURDAY...AS THE SFC HIGH MOVES EAST, THE COLD FRONT FROM THE WEST
BEARS DOWN ON THE FORECAST AREA. AIDING THE COLD FRONT IS THE 500 MB
SHORTWAVE TROUGH THAT IS CHASING THE RIDGE EAST AS WELL. THE MORNING
LOOKS TO REMAIN DRY AS THE MOISTURE AT 850 MB AND IN THE 700-500 MB
LAYER TAKES UNTIL AROUND 18Z TO BEGIN GETTING MOIST ENOUGH TO
SUPPORT PRECIPITATION. THE PROFILE WOULD SUGGEST THAT THE
PRECIPITATION WOULD BE ALL RAIN THROUGH 00Z.
SATURDAY NIGHT...MOISTURE CONTINUES OVER THE REGION AND THE PROFILES
BEGIN TO MOVE TOWARD 0C SO THAT THERE WILL BE A MIX IN E UPPER AND
PROBABLY RAIN IN N LOWER. THE PROFILES DON`T CHANGE MUCH OVERNIGHT
SO THAT A MIX IS WHAT WILL BE EXPECTED. ALSO, THE 700-500 MB LAYER
BEGINS TO DRY OUT SIGNIFICANTLY ENOUGH THAT IT MAY STOP
PRECIPITATING. SO WILL GO WITH THE CHANCE POPS IN E UPPER AND OVER
LAKE MICHIGAN. STILL LOTS OF MOISTURE OVER N LOWER AND LAKE HURON TO
CONTINUE THE LIKELY POPS.
SUNDAY...THE MOISTURE CONTINUES TO MOVE EAST, WITH COLD AIR SPILLING
INTO THE FORECAST AREA. AS THE COLD AIR MOVES IN THE MOISTURE
BEGINS TO MOVE INTO THE REGION WITH SATURATION REACHING -10C. THIS
GETS THE LIGHT SNOW/FLURRIES STARTED AS THE STABILITY BEGINS TO
DECREASE AND UNDER THE 500 MB LOW AND SHORTWAVES ROTATING AROUND
IT. OVERNIGHT, THE 850 MB TEMPERATURES FALL TO AROUND -13C ON THE
ECMWF BY 12Z. THE GFS IS SIGNIFICANTLY COLDER (-17C) AND WOULD
PRODUCE LES FAIRLY WELL WITH THE 500 MB LOW. WILL HEDGE
PESSIMISTIC AS THIS SEASON HAS REMAINED COLDER THAN FIRST THOUGHT.
EXTENDED (MONDAY THROUGH THURSDAY)...MONDAY, LOOKS LIKE THE
TEMPERATURES FALL ENOUGH TO HAVE LES ON BOTH MODELS AS THE ECMWF HAS
-14C AT 850 MB BY 00Z. EARLIER IN THE WEEK, THE WINDS LOOKED
STRONGER, NOW IT LOOKS BREEZY. WILL CONTINUE THE GUSTY WINDS IN THE
HWO. TUESDAY, AS THE SFC HIGH BEGINS TO MOVE INTO THE REGION, THE
850 MB TEMPERATURES BEGIN TO WARM SLIGHTLY, JUST ENOUGH THAT WE MAY
LOSE THE INSTABILITY NEEDED FOR THE LES. THIS CONTINUES INTO THE
NIGHT SO WOULD EXPECT THAT THE SNOW WOULD STOP. 00Z ECMWF SAYS
THAT IT SHOULD. WEDNESDAY, HIGH PRESSURE AT THE SFC AND 500 MB
RIDGE MOVES THROUGH THE REGION SO THAT WE WILL REMAIN DRY FOR THE
DAY. OVERNIGHT, THE ANOTHER COLD FRONT AND 500 MB SHORTWAVE TROUGH
MOVE THROUGH THE REGION. ONE SOLUTION IS WARM ENOUGH FOR RAIN AND
ONE COLD ENOUGH FOR SNOW. SO WILL GO WITH A MIX AT THIS POINT.
THURSDAY, THINK THAT THE GFS IS A LITTLE TOO WET AT 850 MB AND
THINK THAT THE THE ECMWF HAS THE RIGHT IDEA, THAT IS IT IS IN LINE
WITH THE CURRENT FORECAST SO WILL CONTINUE THE DRY DAY AND NIGHT
AT HIGH PRESSURE BEGINS TO BUILD INTO THE REGION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 129 AM EDT FRI MAR 29 2013
SUMMARY: HIGH PRESSURE JUST WEST OF THE GREAT LAKES REGION WILL PUSH
OVERHEAD BRINGING VERY QUIET CONDITIONS THROUGH THE UPCOMING TAF
PERIOD. OUTSIDE OF A FEW HIGH CLOUDS...EXPECT CLEAR SKIES THROUGH
THE TAF PERIOD.
RESTRICTIONS: NONE EXPECTED THROUGH THE TAF PERIOD. CONFIDENCE
HIGH.
WINDS: CALM WINDS THROUGH DAYBREAK WILL BECOME NORTHWEST 5-10KTS BY
MID-LATE MORNING AND THROUGH THE AFTERNOON BEFORE RETURNING TO CALM
FRIDAY NIGHT. A LAKE BREEZE MAY CAUSE THESE NORTHWEST WINDS TO DIE
OFF/SHIFT WEAK SOUTHEAST AT APN BY MID/LATE AFTERNOON.
&&
.MARINE...
ISSUED AT 329 AM EDT FRI MAR 29 2013
SUMMARY: HIGH PRESSURE WILL REMAIN IN CONTROL OF THE REGION/S
WEATHER THROUGH SATURDAY WITH QUIET CONDITIONS OVER THE LAKES. A
COLD FRONT WILL APPROACH SUNDAY...BRINGING STRENGTHENING SOUTHERLY
WINDS. IN IT/S WAKE...NORTHWEST WINDS WILL DEVELOP AND STRENGTHEN
SUNDAY NIGHT INTO MONDAY WITH STRONG WINDS CONTINUING THROUGH
TUESDAY BEFORE HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION FROM
THE WEST.
HEADLINE POTENTIAL: SMALL CRAFT POTENTIAL UNDER SOUTHERLY FLOW
SATURDAY WITH A PROLONGED PERIOD OF SMALL CRAFT WINDS DEVELOPING
BEHIND A STRONG COLD FRONT SUNDAY NIGHT AND CONTINUING THROUGH NEXT
TUESDAY. THERE IS SOME POTENTIAL FOR LOW-END GALE FORCE WINDS IN
THE MONDAY-TUESDAY TIMEFRAME FOR NW FLOW FAVORED AREAS /NEAR
WHITEFISH POINT AND ALONG THE LAKE HURON COAST FROM THE BRIDGE
SOUTHEAST TO PRESQUE ISLE LIGHT/.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...ARNOTT
SYNOPSIS...JL
SHORT TERM...ARNOTT
LONG TERM...JL
AVIATION...ARNOTT
MARINE...ARNOTT
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1003 PM CDT SAT MAR 30 2013
.UPDATE...
DESPITE ELEVATED WIND SPEEDS ACROSS WRN AND SRN MN...DEW POINTS IN
THE LOW-MID 30S IN AREAS WHERE DEEP SNOW PACK REMAINS HAS
PROMOTED THE DEVELOPMENT OF AREAS OF FOG. WINDS HAVE ACTUALLY
BECOME CALM ACROSS WRN WI UNDER CLEAR SKIES WHICH IS A BIT MORE
CONCERNING AND A FEW OBS HAVE REPORTED VIS LESS THAN 1/2 MILE.
DECIDED TO POST A DENSE FOG ADVISORY FOR THESE AREAS WHERE DENSE
FOG HAD BEEN REPORTED EVEN LATE THIS AFTERNOON. ADDED AREAS OF
FOG TO THE GRIDS OVER MUCH OF THE REST OF THE AREA...EXCEPT IN
THE TC METRO AND NORTH ALONG I-35 WHERE VISIBILITIES ARE STILL 10
MILES. A COLD FRONT WILL PUSH THROUGH LATE TONIGHT. INCREASING
CLOUDS...STRONGER WINDS...AND DRIER AIR WILL PUT AN END TO THE FOG
THREAT BETWEEN 4 AND 7 AM FROM WEST TO EAST.
&&
.PREV DISCUSSION.../ISSUED AT 237 PM CDT SAT MAR 30 2013/
OUR RECENT WARM-UP WILL BE COMING TO AN ABRUPT END TONIGHT...
MAKING FOR A CHILLY START TO THE MONTH OF APRIL. IN THE BIG
PICTURE... THE SEEMINGLY EVER- PRESENT EASTERN NORTH AMERICAN
UPPER TROUGH WILL REASSERT ITSELF THROUGH THE FIRST PART OF THE
UPCOMING WEEK... KEEPING UP IN NORTHWEST FLOW WITH PREDOMINANTLY
COLD TEMPERATURES AND DRY WEATHER. HOWEVER... THE FLOW LOOKS TO
FLATTEN OUT WITH A WARMING TREND OVER THE SECOND HALF OF THE WEEK.
THE GFS AND ECMWF ARE ALSO SUGGESTING A MORE SUBSTANTIAL SHIFT IN
THE PATTERN AS WE MOVE INTO THE FOLLOWING WEEK... WITH BOTH 12Z
RUNS SUGGESTING A PROMINENT UPPER RIDGE OVER THE EASTERN CONUS BY
THE 8TH AND 9TH OF APRIL... WITH A DEEP TROUGH OVER THE WESTERN
CONUS DIGGING INTO FAR NORTHERN MEXICO. IF THAT WORKS OUT IT WOULD
MEAN QUITE THE SUBSTANTIAL WARM-UP AS WE MOVE INTO THE START OF
NEXT WEEK... WITH PERHAPS SOME INTERESTING WEATHER OVER THE
CENTRAL PART OF THE COUNTY ONCE THE TROUGH EJECTS EAST. BUT...
THAT/S OBVIOUSLY MANY DAYS AWAY... AND NOT ALL OF THE ENSEMBLE
SOLUTIONS ARE IN LINE WITH THAT THINKING... SO WILL BE SOMETHING
TO MULL OVER AND KEEP AN EYE ON THROUGH THE UPCOMING WEEK. IN THE
MEANTIME... THINGS WILL BE FAIRLY QUIET AND COOL... WITH A FEW
CHANCES FOR PCPN OVER THE UPCOMING SEVEN DAYS.
PCPN ASSOCIATED WITH THE INITIAL FRONTAL PASSAGE HAS EXITED THE
FORECAST AREA... WITH MAINLY PARTLY CLOUDY SKIES DEVELOPING IN ITS
WAKE. HOWEVER... THERE IS AN AREA OF STRATUS AND FOG NORTH OF THE
MINNESOTA RIVER VALLEY AND ALSO ACROSS THE NORTHWEST CWFA NEAR
KAXN. THESE HAVE MIXED OUT SOME DURING THE DAY... BUT LIKELY WILL
NOT GO AWAY ENTIRELY BEFORE NIGHT DESCENDS ON THE AREA. THE
ARCTIC COLD FRONT WILL DROP ACROSS THE AREA TONIGHT BRINGING THE
RETURN OF MUCH BELOW NORMAL TEMPERATURES FOR SEVERAL DAYS. EXPECT
TO SEE SOME SNOW SHOWERS/FLURRIES SQUEEZED OUT AS THE FRONT MOVES
THROUGH THE AREA... WITH PERHAPS SOME FLURRIES LINGERING OVER THE
EAST INTO SUNDAY AS CYCLONIC FLOW AND DECENT BOUNDARY LAYER
MOISTURE PERSIST. STRONG NORTHWEST WINDS WILL OCCUR BEHIND THE
FRONT... ADDING AND ADDITIONAL NIP TO THE AIR THROUGH SUNDAY
BEFORE ARCTIC HIGH PRESSURE BUILDS IN AND WORKS TO KEEP THINGS
COLD AND DRY THROUGH WEDNESDAY. THE GFS AND ECMWF ARE IN
REMARKABLY GOOD AGREEMENT THROUGH THE FORECAST PERIOD... WITH BOTH
BRINGING US INTO RETURN FLOW ON THE BACKSIDE OF THE HIGH BY LATE
WEDNESDAY... THEN SWINGING ANOTHER COLD FRONT THROUGH THE AREA ON
THURSDAY. THAT FRONT WON/T HAVE NEARLY THE PUNCH AS TONIGHT/S...
BUT WILL STILL DELAY THE RETURN OF MUCH WARMER TEMPERATURES. WE
WILL ALSO SEE SOME CHANCE FOR LIGHT PCPN WEDNESDAY INTO EARLY
THURSDAY AHEAD OF THE FRONT. WENT WITH CHANCES FOR RAIN AND SNOW
AT THIS POINT... SINCE IT/S TOUGH TO SAY EXACTLY HOW MUCH WE/LL
WARM BEFORE WE COOL DOWN SLIGHTLY AGAIN. CHANCES FOR MORE
WIDESPREAD PCPN LOOK TO WORK INTO THE AREA LATE FRIDAY INTO
SATURDAY AS WE GET INTO MORE ROBUST RETURN FLOW AND WARM ADVECTION
AHEAD OF A SURFACE LOW THAT LOOKS TO LIFT NORTHEAST ACROSS
MINNESOTA ON SATURDAY. ALLOWED FOR A TRANSITION FROM SNOW TO RAIN
CHANCES WITH THAT SYSTEM... AND A SOMEWHAT EARLIER ARRIVAL THAN
THE 12Z GUIDANCE WOULD SUGGEST. HOWEVER... PREVIOUS RUNS HAD A BIT
MORE UNCERTAINTY WITH THE TIMING... SO WANTED TO TREND THINGS
TOWARD A LATER START WITHOUT ENTIRELY DITCHING EARLIER FORECASTS.
LATEST GUIDANCE WOULD ALSO SHIFT ANY CHANCE OF SNOW WELL NORTH ON
SATURDAY... BUT KEPT SOME MIXED POTENTIAL OVER THE FAR NORTHERN
CWFA TO AT LEAST ALLOW FOR SOME AT THE START OF THE DAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 06Z SUNDAY EVENING)
WATCHING SHORTWAVE ACROSS THE DAKOTAS...ALONG WITH SECONDARY COLD
FRONT MOVING SOUTH ACROSS SRN CAN. SREF IN PARTICULAR WANTING TO
BREAK OUT SOME LIGHT PRECIP NORTH OF I-94 AS THE SHORT WAVE MOVES
ACROSS THE AREA THIS EVENING. DEEP MOISTURE LOOKS TO BE
LACKING...SO HELD ANY PRECIP MENTION IN TAFS TO A VC.
AGAIN...LOCAL HOPWRF HI-RES ENSEMBLE LOOKS TO HAVE A GOOD HANDEL
ON THIS FEATURE...SO USED IT TO TIME ANY VC MENTION IN TAFS. AS
FOR THE COLD FRONT...UNLIKE THIS MORNINGS...THIS SECOND COLD FRONT
WILL BRING WITH IT STRONG COLD AIR ADVECTION AND WITH THAT...A
BANK OF POST FRONTAL STRATUS. 925-850 LAYER RH FROM THE NAM/RAP WAS
USED TO TIME THESE CIGS INTO TERMINALS LATE TONIGHT. HOPWRF
ENSEMBLE SHOWS MVFR CIGS RETURNING AS WELL...THOUGH SEVERAL HOURS
EARLIER. GIVEN THE LACK OF MVFR CIGS CURRENTLY BEING OBS ACROSS
CANADA...FAVORED THE SLOWER TIMING IN THESE TAFS. GIVEN STEEP
LAPSE RATES EXPECTED SUNDAY...SHOULD HAVE NO PROBLEM MAINTAINING
BKN-OVC STRATOCU...QUESTION IS HOW LOW. FOR NOW...PLAYED CONDS TO
TREND TOWARD VFR BY THE AFTERNOON...BUT WE COULD VERY WELL HOLD
CIGS IN THE 020-030 RANGE THROUGH MONDAY NIGHT. OUT IN WRN
MN...BR/HZ OBS HAVE BEEN SLOW TO IMPROVE FROM REMNANT FOG THIS
MORNING...AND WITH A WEAKNESS IN THE PRESSURE FIELD SEEN OUT
THERE...FOLLOWED THE IDEA OF THE HRRR WITH MVFR OR LOWER VSBYS
RETURNING FOR AXN/RWF AHEAD OF THE SECONDARY BOUNDARY...THOUGH
CONFIDENCE IS LOW IN THIS SCENARIO PLAYING OUT AT RWF/AXN.
FINALLY...ON WINDS...DEEP MIXING IS A CERTAINTY TOMORROW...AND
CONFIDENCE IS QUITE HIGH IN NW WINDS GUSTING TO BETWEEN 25 AND 30
KTS MUCH OF THE DAY ON SUNDAY ACROSS MN.
KMSP...CONFIDENCE PRETTY HIGH IN FORECAST THROUGH FIRST 8
HOURS...BUT DECREASES AFTER THAT AS NEXT UPPER LEVEL AND SFC
BOUNDARY APPROACH. HELD BACK ON MVFR CIGS UNTIL 12Z...WHICH IS
WHEN COLD AIR ADVECTION ARRIVES IN FORCE...THOUGH MVFR CONDS COULD
COME IN EARLIER BASED ON HOPWRF PROBS FOR CIGS LESS THAN 3K FT.
FOR NOW...KEPT CIGS ABOVE 017..BUT WOULD NOT RULE OUT CIGS BETWEEN
010 AND 015 SUNDAY MORNING. FOR NOW...SHOW CIGS TRENDING TO
VFR...BUT CONFIDENCE NOT VERY HIGH ON THAT. CONFIDENCE IS HIGH
HOWEVER IN THE WIND FORECAST AND IF ANYTHING...WOULD SAY THE
SPEEDS ARE CONSERVATIVE...THOUGH A 300-320 DIRECTION WILL BE
FAVORABLE FOR AIRPORT OPS.
/OUTLOOK FOR KMSP/
MON...MVFR CIGS POSSIBLE. WINDS NW 15G25KTS.
TUE...VFR. WIND NW 10 KTS.
WED...VFR. WIND S 5-10 KTS BCMG 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...DENSE FOG ADVISORY UNTIL 7 AM CDT SUNDAY FOR WIZ015-016-025-027-
028.
&&
$$
UPDATE...BORGHOFF
PREV DISCUSSION...TRH
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
712 PM CDT SAT MAR 30 2013
.UPDATE...
00Z AVIATION DISCUSSION ADDED BELOW.
&&
.PREVIOUS DISCUSSION...
/ISSUED AT 237 PM CDT SAT MAR 30 2013/
OUR RECENT WARM-UP WILL BE COMING TO AN ABRUPT END TONIGHT...
MAKING FOR A CHILLY START TO THE MONTH OF APRIL. IN THE BIG
PICTURE... THE SEEMINGLY EVER- PRESENT EASTERN NORTH AMERICAN
UPPER TROUGH WILL REASSERT ITSELF THROUGH THE FIRST PART OF THE
UPCOMING WEEK... KEEPING UP IN NORTHWEST FLOW WITH PREDOMINANTLY
COLD TEMPERATURES AND DRY WEATHER. HOWEVER... THE FLOW LOOKS TO
FLATTEN OUT WITH A WARMING TREND OVER THE SECOND HALF OF THE WEEK.
THE GFS AND ECMWF ARE ALSO SUGGESTING A MORE SUBSTANTIAL SHIFT IN
THE PATTERN AS WE MOVE INTO THE FOLLOWING WEEK... WITH BOTH 12Z
RUNS SUGGESTING A PROMINENT UPPER RIDGE OVER THE EASTERN CONUS BY
THE 8TH AND 9TH OF APRIL... WITH A DEEP TROUGH OVER THE WESTERN
CONUS DIGGING INTO FAR NORTHERN MEXICO. IF THAT WORKS OUT IT WOULD
MEAN QUITE THE SUBSTANTIAL WARM-UP AS WE MOVE INTO THE START OF
NEXT WEEK... WITH PERHAPS SOME INTERESTING WEATHER OVER THE
CENTRAL PART OF THE COUNTY ONCE THE TROUGH EJECTS EAST. BUT...
THAT/S OBVIOUSLY MANY DAYS AWAY... AND NOT ALL OF THE ENSEMBLE
SOLUTIONS ARE IN LINE WITH THAT THINKING... SO WILL BE SOMETHING
TO MULL OVER AND KEEP AN EYE ON THROUGH THE UPCOMING WEEK. IN THE
MEANTIME... THINGS WILL BE FAIRLY QUIET AND COOL... WITH A FEW
CHANCES FOR PCPN OVER THE UPCOMING SEVEN DAYS.
PCPN ASSOCIATED WITH THE INITIAL FRONTAL PASSAGE HAS EXITED THE
FORECAST AREA... WITH MAINLY PARTLY CLOUDY SKIES DEVELOPING IN ITS
WAKE. HOWEVER... THERE IS AN AREA OF STRATUS AND FOG NORTH OF THE
MINNESOTA RIVER VALLEY AND ALSO ACROSS THE NORTHWEST CWFA NEAR
KAXN. THESE HAVE MIXED OUT SOME DURING THE DAY... BUT LIKELY WILL
NOT GO AWAY ENTIRELY BEFORE NIGHT DESCENDS ON THE AREA. THE
ARCTIC COLD FRONT WILL DROP ACROSS THE AREA TONIGHT BRINGING THE
RETURN OF MUCH BELOW NORMAL TEMPERATURES FOR SEVERAL DAYS. EXPECT
TO SEE SOME SNOW SHOWERS/FLURRIES SQUEEZED OUT AS THE FRONT MOVES
THROUGH THE AREA... WITH PERHAPS SOME FLURRIES LINGERING OVER THE
EAST INTO SUNDAY AS CYCLONIC FLOW AND DECENT BOUNDARY LAYER
MOISTURE PERSIST. STRONG NORTHWEST WINDS WILL OCCUR BEHIND THE
FRONT... ADDING AND ADDITIONAL NIP TO THE AIR THROUGH SUNDAY
BEFORE ARCTIC HIGH PRESSURE BUILDS IN AND WORKS TO KEEP THINGS
COLD AND DRY THROUGH WEDNESDAY. THE GFS AND ECMWF ARE IN
REMARKABLY GOOD AGREEMENT THROUGH THE FORECAST PERIOD... WITH BOTH
BRINGING US INTO RETURN FLOW ON THE BACKSIDE OF THE HIGH BY LATE
WEDNESDAY... THEN SWINGING ANOTHER COLD FRONT THROUGH THE AREA ON
THURSDAY. THAT FRONT WON/T HAVE NEARLY THE PUNCH AS TONIGHT/S...
BUT WILL STILL DELAY THE RETURN OF MUCH WARMER TEMPERATURES. WE
WILL ALSO SEE SOME CHANCE FOR LIGHT PCPN WEDNESDAY INTO EARLY
THURSDAY AHEAD OF THE FRONT. WENT WITH CHANCES FOR RAIN AND SNOW
AT THIS POINT... SINCE IT/S TOUGH TO SAY EXACTLY HOW MUCH WE/LL
WARM BEFORE WE COOL DOWN SLIGHTLY AGAIN. CHANCES FOR MORE
WIDESPREAD PCPN LOOK TO WORK INTO THE AREA LATE FRIDAY INTO
SATURDAY AS WE GET INTO MORE ROBUST RETURN FLOW AND WARM ADVECTION
AHEAD OF A SURFACE LOW THAT LOOKS TO LIFT NORTHEAST ACROSS
MINNESOTA ON SATURDAY. ALLOWED FOR A TRANSITION FROM SNOW TO RAIN
CHANCES WITH THAT SYSTEM... AND A SOMEWHAT EARLIER ARRIVAL THAN
THE 12Z GUIDANCE WOULD SUGGEST. HOWEVER... PREVIOUS RUNS HAD A BIT
MORE UNCERTAINTY WITH THE TIMING... SO WANTED TO TREND THINGS
TOWARD A LATER START WITHOUT ENTIRELY DITCHING EARLIER FORECASTS.
LATEST GUIDANCE WOULD ALSO SHIFT ANY CHANCE OF SNOW WELL NORTH ON
SATURDAY... BUT KEPT SOME MIXED POTENTIAL OVER THE FAR NORTHERN
CWFA TO AT LEAST ALLOW FOR SOME AT THE START OF THE DAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 06Z SUNDAY EVENING)
WATCHING SHORTWAVE ACROSS THE DAKOTAS...ALONG WITH SECONDARY COLD
FRONT MOVING SOUTH ACROSS SRN CAN. SREF IN PARTICULAR WANTING TO
BREAK OUT SOME LIGHT PRECIP NORTH OF I-94 AS THE SHORT WAVE MOVES
ACROSS THE AREA THIS EVENING. DEEP MOISTURE LOOKS TO BE
LACKING...SO HELD ANY PRECIP MENTION IN TAFS TO A VC.
AGAIN...LOCAL HOPWRF HI-RES ENSEMBLE LOOKS TO HAVE A GOOD HANDEL
ON THIS FEATURE...SO USED IT TO TIME ANY VC MENTION IN TAFS. AS
FOR THE COLD FRONT...UNLIKE THIS MORNINGS...THIS SECOND COLD FRONT
WILL BRING WITH IT STRONG COLD AIR ADVECTION AND WITH THAT...A
BANK OF POST FRONTAL STRATUS. 925-850 LAYER RH FROM THE NAM/RAP WAS
USED TO TIME THESE CIGS INTO TERMINALS LATE TONIGHT. HOPWRF
ENSEMBLE SHOWS MVFR CIGS RETURNING AS WELL...THOUGH SEVERAL HOURS
EARLIER. GIVEN THE LACK OF MVFR CIGS CURRENTLY BEING OBS ACROSS
CANADA...FAVORED THE SLOWER TIMING IN THESE TAFS. GIVEN STEEP
LAPSE RATES EXPECTED SUNDAY...SHOULD HAVE NO PROBLEM MAINTAINING
BKN-OVC STRATOCU...QUESTION IS HOW LOW. FOR NOW...PLAYED CONDS TO
TREND TOWARD VFR BY THE AFTERNOON...BUT WE COULD VERY WELL HOLD
CIGS IN THE 020-030 RANGE THROUGH MONDAY NIGHT. OUT IN WRN
MN...BR/HZ OBS HAVE BEEN SLOW TO IMPROVE FROM REMNANT FOG THIS
MORNING...AND WITH A WEAKNESS IN THE PRESSURE FIELD SEEN OUT
THERE...FOLLOWED THE IDEA OF THE HRRR WITH MVFR OR LOWER VSBYS
RETURNING FOR AXN/RWF AHEAD OF THE SECONDARY BOUNDARY...THOUGH
CONFIDENCE IS LOW IN THIS SCENARIO PLAYING OUT AT RWF/AXN.
FINALLY...ON WINDS...DEEP MIXING IS A CERTAINTY TOMORROW...AND
CONFIDENCE IS QUITE HIGH IN NW WINDS GUSTING TO BETWEEN 25 AND 30
KTS MUCH OF THE DAY ON SUNDAY ACROSS MN.
KMSP...CONFIDENCE PRETTY HIGH IN FORECAST THROUGH FIRST 8
HOURS...BUT DECREASES AFTER THAT AS NEXT UPPER LEVEL AND SFC
BOUNDARY APPROACH. HELD BACK ON MVFR CIGS UNTIL 12Z...WHICH IS
WHEN COLD AIR ADVECTION ARRIVES IN FORCE...THOUGH MVFR CONDS COULD
COME IN EARLIER BASED ON HOPWRF PROBS FOR CIGS LESS THAN 3K FT.
FOR NOW...KEPT CIGS ABOVE 017..BUT WOULD NOT RULE OUT CIGS BETWEEN
010 AND 015 SUNDAY MORNING. FOR NOW...SHOW CIGS TRENDING TO
VFR...BUT CONFIDENCE NOT VERY HIGH ON THAT. CONFIDENCE IS HIGH
HOWEVER IN THE WIND FORECAST AND IF ANYTHING...WOULD SAY THE
SPEEDS ARE CONSERVATIVE...THOUGH A 300-320 DIRECTION WILL BE
FAVORABLE FOR AIRPORT OPS.
/OUTLOOK FOR KMSP/
MON...MVFR CIGS POSSIBLE. WINDS NW 15G25KTS.
TUE...VFR. WIND NW 10 KTS.
WED...VFR. WIND S 5-10 KTS BCMG 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
318 PM CDT FRI MAR 29 2013
.SYNOPSIS...
ISSUED AT 318 PM CDT FRI MAR 29 2013
H5 HAND ANALYSIS THIS MORNING IS INDICATING BROAD LOW
AMPLITUDE FLOW ACROSS THE LOWER 48...WITH EMBEDDED SHORTWAVES NOTED
OVER THE NORTHERN ROCKIES OF IDAHO AND MONTANA. ABUNDANT MID LEVEL
INSTABILITY AND MID LEVEL ALTO CU HAS TRACKED INTO WESTERN AND
CENTRAL NEBRASKA THIS MORNING...WITH RADAR INDICATING HIGHLY
ELEVATED SHOWERS...NONE OF WHICH IS REACHING THE GROUND ATTM. AT THE
SURFACE...A LEE SIDE TROUGH HAS BEGUN TO DEEPEN ACROSS THE PANHANDLE
AND FAR EASTERN COLORADO OVER THE PAST COUPLE OF HOURS. THIS HAS
RESULTED IN INCREASED SRLY WINDS THIS AFTERNOON AND INCREASED LOW
LEVEL MOISTURE...WITH DEW POINTS BEGINNING TO REACH INTO THE LOWER
40S AS OF 3 PM CDT. TEMPERATURES AS OF 3 PM CDT RANGED FROM 64
DEGREES AT VALENTINE TO 71 DEGREES AT OGALLALA.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 318 PM CDT FRI MAR 29 2013
MAIN FORECASTING CHALLENGES
OVER THE NEXT 24 HOURS ARE THUNDERSTORM POTENTIAL AND ASSOCIATED
PRECIPITATION CHANCES TONIGHT...THEN LOW PRECIPITATION CHANCES FOR
SATURDAY...IN PARTICULAR SATURDAY AFTERNOON. FOR TONIGHT...AM
EXPECTING SOME ISOLATED TSRA INITIATION INVOF OF SURFACE TROUGH AXIS
LATER THIS AFTERNOON. BASED ON THE LATEST NAM AND RUC SOLNS...THIS
SHOULD BE SOMEWHERE FROM AROUND OGALLALA TO NORTHERN CHERRY COUNTY
BY 21Z THIS AFTERNOON. AM EXPECTING ISOLATED CONVECTION TO FIRE
INVOF OF THIS FEATURE DURING THE 21Z TO 00Z TIME FRAME LATER THIS
AFTERNOON. DECENT MID LEVEL FLOW...WILL TRACK ANY ISOLATED
CONVECTION QUICKLY EAST INTO THE CENTRAL AND EASTERN CWFA LATER THIS
EVENING AND OVERNIGHT. CONVECTION IS EXPECTED TO BECOME BETTER
ORGANIZED IN THE EASTERN CWFA OVERNIGHT AS A NICE LOW LEVEL JET
PUSHES NORTH INTO EASTERN NEBR...THE NOSE OF WHICH PUSHES INTO OUR
NERN ZONES. FOR PRECIPITATION CHANCES TONIGHT...FAVORED POPS AROUND
20 PERCENT...ALONG AND WEST OF HIGHWAY 83...INCREASING THEM EASTWARD
TO AROUND 50 PERCENT IN THE NERN CWA. AS FOR THE THREAT OF SEVERE
THUNDERSTORMS TONIGHT...THE LATEST SWODY1 HAS A SEE TEXT ACROSS OUR
SWRN ZONES AND CENTRAL SANDHILLS MAINLY FOR EARLY EVENING CONVECTION
TIED TO PEAK HEATING. AT THIS JUNCTURE...SOME GUSTY WINDS MAY
ACCOMPANY THE STRONGEST STORMS GIVEN THE DRY CONDS BLO 10000 FT AGL
AND EXPECTED HIGH BASED TSRAS IN THE WEST. EVEN IN LIGHT OF WET BULB
ZEROES OF AROUND 9000 FT MSL...LARGE HAIL THREAT WILL BE MINIMAL AS
DEEP LAYER SHEAR IS ONLY AROUND 30 KTS AND FREEZING LEVELS ARE
AROUND 5 TO 7 THOUSAND FT AGL.
FOR SATURDAY...NORTHWESTERLY WINDS WILL DEVELOP BEHIND EXITING LOW
PRESSURE AND MAY BECOME GUSTY DURING THE AFTERNOON HOURS. WITH
SURFACE HEATING...MID LEVEL LAPSE RATES WILL STEEPEN SIGNIFICANTLY
DURING THE AFTERNOON HOURS...AND WILL CONTINUE MENTION OF ISOLATED
SHOWERS. LI`S ARE BARELY NEGATIVE TOMORROW AFTERNOON AND WILL FORGO
MENTION OF THUNDER ATTM. HIGHS SATURDAY WILL BE COOLER THAN TDYS
READINGS. BASED ON H85 TEMPS AND GOOD MIXING...HIGHS WILL RANGE FROM
THE 50S NORTH...TO THE LOWER 60S IN THE SOUTH.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 318 PM CDT FRI MAR 29 2013
SATURDAY NIGHT WILL SEE A DISTURBANCE PUSHING SOUTH AND AN ARCTIC
COLD FRONT DIPPING SOUTH ACROSS THE NORTHERN PLAINS. BY SUNDAY
AFTERNOON THE COLD FRONT WILL BE PUSHING INTO NRN NEBRASKA. SHOULD
SQUEAK OUT ANOTHER NICE DAY WITH HIGHS IN THE 60S FOR MOST OF THE
CWA. PORTIONS OF NORTH CENTRAL WILL SEE HIGHS ONLY IN THE 50S AS THE
COLD FRONT ARRIVES BEFORE PEAK HEAT. ALSO GOING TO SEE SOME SHOWERS
DEVELOP ALONG/AHEAD OF THE FRONT...MAINLY WHERE THERE IS BETTER
MOISTURE TO THE EAST. BY SUNDAY NIGHT COLD AIR WILL PUSH ACROSS THE
AREA. NOT A GREAT CHANCE FOR PRECIP...BUT COLD AIR ALOFT WILL CREATE
SOME STEEP LAPSE RATES. ALSO AS TEMPS FALL A MIX OR CHANGE TO SNOW
CAN BE EXPECTED.
MONDAY WILL FEEL THE COLD ARCTIC AIR AS HIGHS ONLY WARM INTO THE MID
30S TO MID 40S. PRECIP WILL BE PUSHING SOUTH...SO HIGHS MAY ACTUALLY
BE ABLE TO WARM UP A LITTLE MORE THAN FORECAST AS APRIL SUNSHINE
ARRIVES FOR THE AFTERNOON.
COLD AIR IS SHORT LIVED AS CENTER OF HIGH SHIFTS TO THE EAST FOR
TUESDAY...WITH RETURN SOUTHERLY FLOW BY TUESDAY AFTERNOON. NOT A
FAST REBOUND ON TUESDAY AS HIGHS ONLY IN THE 40S TO LOW 50S.
WEDNESDAY INTO THURSDAY WILL CONTINUE TO SEE A REBOUND OF TEMPS.
SURF HIGH CONTINUES TO PUSH TO THE SE WITH MORE WARM AIR TO PUSH
NORTHWARD AND THE BACKSIDE OF THE HIGH. 850 MB TEMPS PUSH INTO THE
SINGLE DIGITS ABOVE ZERO AND CLOSE TO 10 IN THE WEST WITH GUIDANCE
CLOSE TO 60. PRECIP CHANCES DO NOT LOOK GOOD THROUGH THE WEEK...AS
GULF MOISTURE REMAINS SHUT OFF AND MODELS CONTINUE A DRY BL. AN
UPPER LEVEL DISTURBANCE LATE IN THE WEEK MAY BRING SOME LIGHT
PRECIP...BUT WILL HAVE TO BE A TOP DOWN SATURATION AND DO NOT HAVE
IN THE FORECAST ATTM.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1250 CDT FRI MAR 29 2013
GENERALLY VRF CONDITIONS THE NEXT 24 HOURS. TROUGH MOVING ACROSS
THE AREA THIS EVENING. WEAK INSTABILITY SHOULD BE ENOUGH FOR
ISOLD TO SCT THUNDERSTORM DEVELOPMENT. DEVELOPMENT IS EXPECTED
ACROSS WESTERN NEBRASKA AROUND 22Z TO 23Z AND PROGRESS EASTWARD.
AM EXPECTING IMPACT AT BOTH TERMINALS...KLBF AND KVTN...HOWEVER
DURATION WILL NOT BE LONG. COULD SEE A BRIEF REDUCTION TO MVFR
VSBY...HOWEVER THE THUNDER WILL BE THE MAIN CONCERN. BY 01Z THE
STORMS SHOULD BE EAST OF THE TERMINALS. WINDS TODAY WILL BE
SOUTHERLY...BECOMING NORTHWESTERLY OVERNIGHT...BEHIND THE TROUGH.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...CLB
LONG TERM...MASEK
AVIATION...MASEK
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1244 PM CDT FRI MAR 29 2013
.AVIATION...
18Z TAFS FOR KOMA...KLNK AND KOFK.
VFR CONDITIONS ARE EXPECTED THROUGH AT LEAST 04Z THEN ARE EXPECTED
TO DETERIORATE AS AN AREA OF SHOWERS DEVELOPS TO THE WEST AND
DRIFTS SOUTHEAST AHEAD OF AN APPROCHING COLD FRONT. A FEW
ISOLATED THUNDERSTORMS ARE POSSIBLE BUT WILL LEAVE THE MENTION OUT
OF THE TAFS FOR NOW WITH ANOTHER MAIN TAF ISSUANCE BETWEEN NOW
AND THE TIME ANY DEVELOPMENT WOULD OCCUR. CIGS MAY DROP TO MVFR OR
EVEN AS LOW AS IFR IN THE SHOWERS. SFC WINDS WILL TURN TO THE
NORTHWEST AROUND 12Z AS THE SFC COLD FRONT PUSHES ACROSS THE
SITES.
&&
.PREV DISCUSSION... /ISSUED 340 AM CDT FRI MAR 29 2013/
SHORT TERM...TODAY THROUGH SATURDAY NIGHT.
THE MAIN FORECAST CONCERNS IN THIS PERIOD ARE CHANCES FOR SHOWERS/
THUNDERSTORMS AND TEMPERATURES.
TEMPERATURES YESTERDAY TOPPED OUT MAINLY IN THE UPPER 50S AND LOWER
60S ACROSS THE FORECAST AREA. HIGHS TODAY SHOULD BE ABOUT 3 TO 5
DEGREES WARMER...BASED ON A SMALL INCREASE IN 850 MB TEMPS. THERE
IS SOME CONCERN THAT PCPN COULD DEVELOP LATE THIS AFTERNOON AS LOW
LEVEL MOISTURE AND INSTABILITY INCREASE. BUT BASED ON MOST RECENT
FORECASTS OF MOST UNSTABLE CAPE FORECASTS FROM RAP MODEL...KEPT
THINGS DRY UNTIL THIS EVENING. 850 MB DEWPOINTS WERE IN THE 5 TO
10 DEGREE CELSIUS RANGE LAST EVENING ACROSS THE SOUTHERN
PLAINS... MAINLY FROM OKLAHOMA SOUTH. MODEL SHOW MOISTURE
INCREASING IN OUR AREA...BUT MAIN AXIS STAYS MAINLY TO OUR WEST IN
CENTRAL NEBRASKA THROUGH 00Z THIS EVENING. THIS 850 MB MOISTURE
SHOULD SPREAD OVER OUR AREA TONIGHT AND THEN OUT OF THE AREA
SATURDAY. KEPT FAIRLY HIGH POPS GOING FOR TONIGHT AND SATURDAY
MORNING. SOME OF THE MODEL QPFS LOOK A LITTLE HIGH...BUT CERTAINLY
AMOUNTS BETWEEN A TENTH AND A QUARTER OF AN INCH SEEM
REASONABLE...WITH LOCALLY HIGHER AMOUNTS POSSIBLE. COMBINATION OF
CLOUD COVER AND WIND SHOULD HELP KEEP LOWS TONIGHT IN THE 40S MOST
SPOTS.
ON SATURDAY...A WIND SHIFT WILL MOVE ACROSS THE AREA...BUT 850 MB
TEMPERATURES DO NOT CHANGE MUCH AND MIXING SHOULD BE GOOD. STAYED
FAIRLY CLOSE TO PREVIOUS FORECAST FOR HIGHS SATURDAY...RANGING
FROM UPPER 50S NORTH TO MID OR UPPER 60S FAR SOUTH. IF CLOUDS AND
PCPN CLEAR OUT FASTER THAN CURRENTLY EXPECTED...HIGHS COULD BE A
LITTLE WARMER NORTHERN AND CENTRAL ZONES. SATURDAY NIGHT WE ARE
BETWEEN SYSTEMS AND FOR NOW KEPT THINGS DRY. SOME SHOWERS COULD
DEVELOP TO OUR WEST IN THE AFTERNOON BUT FOR NOW EXPECTED THESE TO
DISSIPATE SATURDAY EVENING BEFORE REACHING SOUTHEAST NEBRASKA.
LOWS WILL DROP INTO THE 30S SATURDAY NIGHT.
MILLER
LONG TERM...SUNDAY THROUGH THURSDAY.
MAIN CONCERNS IN THIS PERIOD ARE TEMPERATURES SUNDAY AND PCPN
CHANCES FOR SUNDAY INTO SUNDAY NIGHT. A STRONG COLD FRONT WILL BE
PUSHING INTO OUR NORTHERN ZONES SUNDAY AFTERNOON...SO JUST HOW WARM
IT WILL GET IS PROBLEMATIC. AIRMASS WILL BE STARTING OUT QUITE
MILD...BUT TEMPERATURES SHOULD BE FALLING IN THE AFTERNOON ACROSS
NORTHEAST NEBRASKA AS WINDS SHIFT TO THE NORTH. WENT WITH HIGHS
CLOSE TO NOON NORTH IN THE 50S...BUT IN THE 60S MID OR LATE
AFTERNOON SOUTH. BUT AGAIN THIS WILL DEPEND ON FRONTAL TIMING.
AREAS ALONG THE KANSAS BORDER COULD APPROACH 70...BUT DID NOT
WANT TO GET TOO OPTIMISTIC AT THIS POINT. FAIRLY DECENT FORCING IS
EXPECTED ALONG AND BEHIND THE FRONT...SO KEPT POPS 20 TO 30
PERCENT MOST AREAS SUNDAY AFTERNOON. PCPN TYPE WILL BE AN ISSUE
AS THE COLD AIR POURS IN FOR SUNDAY NIGHT...WITH RAIN CHANGING TO
SNOW. TRIED TO ADD SOME DETAIL TO PCPN TYPE SUNDAY NIGHT BUT
THIS WILL BE REFINED AS WE GET CLOSER. DID NOT MENTION ANY SNOW
ACCUMULATION AT THIS POINT...BUT THAT WILL NEED TO BE MONITORED
CLOSELY. HIGHS MONDAY SHOULD ONLY REACH THE 30S...BUT THEN LOOK
FOR MODERATING TEMPERATURES THROUGH THURSDAY AS MILDER AIR MOVES
IN FROM THE SOUTH AND WEST.
MILLER
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
628 AM CDT FRI MAR 29 2013
.AVIATION...
12Z TAFS FOR KOMA...KLNK...KOFK.
VFR CONDITIONS EXPECTED THROUGH 03Z THEN CONDITIONS EXPECTED TO
DETERIORATE FOR THE REMAINDER OF THE PERIOD AS APPROACHING COLD
FRONT BRINGS SCATTERED SHOWERS AND THUNDERSTORMS INTO THE AREA
WITH MVFR CIGS AND VSBYS.
&&
.PREV DISCUSSION... /ISSUED 340 AM CDT FRI MAR 29 2013/
SHORT TERM...TODAY THROUGH SATURDAY NIGHT.
THE MAIN FORECAST CONCERNS IN THIS PERIOD ARE CHANCES FOR SHOWERS/
THUNDERSTORMS AND TEMPERATURES.
TEMPERATURES YESTERDAY TOPPED OUT MAINLY IN THE UPPER 50S AND LOWER
60S ACROSS THE FORECAST AREA. HIGHS TODAY SHOULD BE ABOUT 3 TO 5
DEGREES WARMER...BASED ON A SMALL INCREASE IN 850 MB TEMPS. THERE
IS SOME CONCERN THAT PCPN COULD DEVELOP LATE THIS AFTERNOON AS LOW
LEVEL MOISTURE AND INSTABILITY INCREASE. BUT BASED ON MOST RECENT
FORECASTS OF MOST UNSTABLE CAPE FORECASTS FROM RAP MODEL...KEPT
THINGS DRY UNTIL THIS EVENING. 850 MB DEWPOINTS WERE IN THE 5 TO
10 DEGREE CELSIUS RANGE LAST EVENING ACROSS THE SOUTHERN
PLAINS... MAINLY FROM OKLAHOMA SOUTH. MODEL SHOW MOISTURE
INCREASING IN OUR AREA...BUT MAIN AXIS STAYS MAINLY TO OUR WEST IN
CENTRAL NEBRASKA THROUGH 00Z THIS EVENING. THIS 850 MB MOISTURE
SHOULD SPREAD OVER OUR AREA TONIGHT AND THEN OUT OF THE AREA
SATURDAY. KEPT FAIRLY HIGH POPS GOING FOR TONIGHT AND SATURDAY
MORNING. SOME OF THE MODEL QPFS LOOK A LITTLE HIGH...BUT CERTAINLY
AMOUNTS BETWEEN A TENTH AND A QUARTER OF AN INCH SEEM
REASONABLE...WITH LOCALLY HIGHER AMOUNTS POSSIBLE. COMBINATION OF
CLOUD COVER AND WIND SHOULD HELP KEEP LOWS TONIGHT IN THE 40S MOST
SPOTS.
ON SATURDAY...A WIND SHIFT WILL MOVE ACROSS THE AREA...BUT 850 MB
TEMPERATURES DO NOT CHANGE MUCH AND MIXING SHOULD BE GOOD. STAYED
FAIRLY CLOSE TO PREVIOUS FORECAST FOR HIGHS SATURDAY...RANGING
FROM UPPER 50S NORTH TO MID OR UPPER 60S FAR SOUTH. IF CLOUDS AND
PCPN CLEAR OUT FASTER THAN CURRENTLY EXPECTED...HIGHS COULD BE A
LITTLE WARMER NORTHERN AND CENTRAL ZONES. SATURDAY NIGHT WE ARE
BETWEEN SYSTEMS AND FOR NOW KEPT THINGS DRY. SOME SHOWERS COULD
DEVELOP TO OUR WEST IN THE AFTERNOON BUT FOR NOW EXPECTED THESE TO
DISSIPATE SATURDAY EVENING BEFORE REACHING SOUTHEAST NEBRASKA.
LOWS WILL DROP INTO THE 30S SATURDAY NIGHT.
MILLER
LONG TERM...SUNDAY THROUGH THURSDAY.
MAIN CONCERNS IN THIS PERIOD ARE TEMPERATURES SUNDAY AND PCPN
CHANCES FOR SUNDAY INTO SUNDAY NIGHT. A STRONG COLD FRONT WILL BE
PUSHING INTO OUR NORTHERN ZONES SUNDAY AFTERNOON...SO JUST HOW WARM
IT WILL GET IS PROBLEMATIC. AIRMASS WILL BE STARTING OUT QUITE
MILD...BUT TEMPERATURES SHOULD BE FALLING IN THE AFTERNOON ACROSS
NORTHEAST NEBRASKA AS WINDS SHIFT TO THE NORTH. WENT WITH HIGHS
CLOSE TO NOON NORTH IN THE 50S...BUT IN THE 60S MID OR LATE
AFTERNOON SOUTH. BUT AGAIN THIS WILL DEPEND ON FRONTAL TIMING.
AREAS ALONG THE KANSAS BORDER COULD APPROACH 70...BUT DID NOT
WANT TO GET TOO OPTIMISTIC AT THIS POINT. FAIRLY DECENT FORCING IS
EXPECTED ALONG AND BEHIND THE FRONT...SO KEPT POPS 20 TO 30
PERCENT MOST AREAS SUNDAY AFTERNOON. PCPN TYPE WILL BE AN ISSUE
AS THE COLD AIR POURS IN FOR SUNDAY NIGHT...WITH RAIN CHANGING TO
SNOW. TRIED TO ADD SOME DETAIL TO PCPN TYPE SUNDAY NIGHT BUT
THIS WILL BE REFINED AS WE GET CLOSER. DID NOT MENTION ANY SNOW
ACCUMULATION AT THIS POINT...BUT THAT WILL NEED TO BE MONITORED
CLOSELY. HIGHS MONDAY SHOULD ONLY REACH THE 30S...BUT THEN LOOK
FOR MODERATING TEMPERATURES THROUGH THURSDAY AS MILDER AIR MOVES
IN FROM THE SOUTH AND WEST.
MILLER
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
FOBERT
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
340 AM CDT FRI MAR 29 2013
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT.
THE MAIN FORECAST CONCERNS IN THIS PERIOD ARE CHANCES FOR SHOWERS/
THUNDERSTORMS AND TEMPERATURES.
TEMPERATURES YESTERDAY TOPPED OUT MAINLY IN THE UPPER 50S AND LOWER
60S ACROSS THE FORECAST AREA. HIGHS TODAY SHOULD BE ABOUT 3 TO 5
DEGREES WARMER...BASED ON A SMALL INCREASE IN 850 MB TEMPS. THERE
IS SOME CONCERN THAT PCPN COULD DEVELOP LATE THIS AFTERNOON AS LOW
LEVEL MOISTURE AND INSTABILITY INCREASE. BUT BASED ON MOST RECENT
FORECASTS OF MOST UNSTABLE CAPE FORECASTS FROM RAP MODEL...KEPT
THINGS DRY UNTIL THIS EVENING. 850 MB DEWPOINTS WERE IN THE 5 TO
10 DEGREE CELSIUS RANGE LAST EVENING ACROSS THE SOUTHERN
PLAINS... MAINLY FROM OKLAHOMA SOUTH. MODEL SHOW MOISTURE
INCREASING IN OUR AREA...BUT MAIN AXIS STAYS MAINLY TO OUR WEST IN
CENTRAL NEBRASKA THROUGH 00Z THIS EVENING. THIS 850 MB MOISTURE
SHOULD SPREAD OVER OUR AREA TONIGHT AND THEN OUT OF THE AREA
SATURDAY. KEPT FAIRLY HIGH POPS GOING FOR TONIGHT AND SATURDAY
MORNING. SOME OF THE MODEL QPFS LOOK A LITTLE HIGH...BUT CERTAINLY
AMOUNTS BETWEEN A TENTH AND A QUARTER OF AN INCH SEEM
REASONABLE...WITH LOCALLY HIGHER AMOUNTS POSSIBLE. COMBINATION OF
CLOUD COVER AND WIND SHOULD HELP KEEP LOWS TONIGHT IN THE 40S MOST
SPOTS.
ON SATURDAY...A WIND SHIFT WILL MOVE ACROSS THE AREA...BUT 850 MB
TEMPERATURES DO NOT CHANGE MUCH AND MIXING SHOULD BE GOOD. STAYED
FAIRLY CLOSE TO PREVIOUS FORECAST FOR HIGHS SATURDAY...RANGING
FROM UPPER 50S NORTH TO MID OR UPPER 60S FAR SOUTH. IF CLOUDS AND
PCPN CLEAR OUT FASTER THAN CURRENTLY EXPECTED...HIGHS COULD BE A
LITTLE WARMER NORTHERN AND CENTRAL ZONES. SATURDAY NIGHT WE ARE
BETWEEN SYSTEMS AND FOR NOW KEPT THINGS DRY. SOME SHOWERS COULD
DEVELOP TO OUR WEST IN THE AFTERNOON BUT FOR NOW EXPECTED THESE TO
DISSIPATE SATURDAY EVENING BEFORE REACHING SOUTHEAST NEBRASKA.
LOWS WILL DROP INTO THE 30S SATURDAY NIGHT.
MILLER
.LONG TERM...SUNDAY THROUGH THURSDAY.
MAIN CONCERNS IN THIS PERIOD ARE TEMPERATURES SUNDAY AND PCPN
CHANCES FOR SUNDAY INTO SUNDAY NIGHT. A STRONG COLD FRONT WILL BE
PUSHING INTO OUR NORTHERN ZONES SUNDAY AFTERNOON...SO JUST HOW WARM
IT WILL GET IS PROBLEMATIC. AIRMASS WILL BE STARTING OUT QUITE
MILD...BUT TEMPERATURES SHOULD BE FALLING IN THE AFTERNOON ACROSS
NORTHEAST NEBRASKA AS WINDS SHIFT TO THE NORTH. WENT WITH HIGHS
CLOSE TO NOON NORTH IN THE 50S...BUT IN THE 60S MID OR LATE
AFTERNOON SOUTH. BUT AGAIN THIS WILL DEPEND ON FRONTAL TIMING.
AREAS ALONG THE KANSAS BORDER COULD APPROACH 70...BUT DID NOT
WANT TO GET TOO OPTIMISTIC AT THIS POINT. FAIRLY DECENT FORCING IS
EXPECTED ALONG AND BEHIND THE FRONT...SO KEPT POPS 20 TO 30
PERCENT MOST AREAS SUNDAY AFTERNOON. PCPN TYPE WILL BE AN ISSUE
AS THE COLD AIR POURS IN FOR SUNDAY NIGHT...WITH RAIN CHANGING TO
SNOW. TRIED TO ADD SOME DETAIL TO PCPN TYPE SUNDAY NIGHT BUT
THIS WILL BE REFINED AS WE GET CLOSER. DID NOT MENTION ANY SNOW
ACCUMULATION AT THIS POINT...BUT THAT WILL NEED TO BE MONITORED
CLOSELY. HIGHS MONDAY SHOULD ONLY REACH THE 30S...BUT THEN LOOK
FOR MODERATING TEMPERATURES THROUGH THURSDAY AS MILDER AIR MOVES
IN FROM THE SOUTH AND WEST.
MILLER
&&
.AVIATION...
06Z TAFS FOR KOMA...KLNK...KOFK.
LIGHT FOG REMAINS A SMALL RISK AT TAF SITES LATE TONIGHT...BUT
DWPTS HAVE REMAINED LOW ENOUGH SO THAT CHANCES APPEARED TOO SMALL
TO INCLUDE IN 06Z TAFS. A DISTURBANCE TRACKING ACROSS THE DAKOTAS
LATE FRIDAY WILL BRING INCREASING MID CLOUDS AND POSSIBLY MVFR
CIGS TO TAF SITES FRIDAY NIGHT...ALONG WITH SCT SHOWERS/
THUNDERSTORMS. IT APPEARED MVFR OR LOWER CIGS...IF THEY OCCURRED...
WOULD HOLD OFF UNTIL AFTER 30/06Z. SHOWERS COULD APPROACH KOFK
VICINITY BEFORE 30/06Z AND A PROB30 GROUP WAS INCLUDED AT THAT
SITE LAST 3 HRS OF TAF PERIOD. APPEARS SHOWER CHANCES AT KOMA AND
KLNK WOULD BE MAINLY AFTER 30/06Z.
CHERMOK
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
704 PM EDT FRI MAR 29 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE AND ASSOCIATED SURFACE COLD FRONT WILL
SHIFT SOUTHEASTWARD ACROSS THE NORTH COUNTRY DURING THE LATE
AFTERNOON AND EVENING HOURS...BRINGING SCATTERED RAIN SHOWERS AND
HIGHER ELEVATION SNOW SHOWERS. PRECIPITATION WILL END DURING THE
PRE-DAWN HOURS SATURDAY. SURFACE HIGH PRESSURE BUILDS INTO THE
NORTH COUNTRY DURING SATURDAY BRINGING MOSTLY SUNNY SKIES AND
VALLEY TEMPERATURES IN THE UPPER 40S TO LOWER 50S. CLOUDS WILL
INCREASE DURING SUNDAY...WITH THE NEXT FRONTAL SYSTEM BRINGING
RAIN LATE SUNDAY AFTERNOON INTO SUNDAY NIGHT.
&&
.NEAR TERM /UNTIL 7 AM SATURDAY MORNING/...
AS OF 651 PM EDT FRIDAY...RECENT COMPOSITE RADAR IMAGERY SHOWS AN
OVERALL DECREASE IN COVERAGE OF INSTABILITY RAIN/MTN SNOW SHOWERS
ACROSS THE NORTH COUNTRY LATE THIS AFTERNOON. WATER VAPOR IMAGERY
AND RAP OBJECTIVE ANALYSES SUGGEST THE THE WEAK SHORTWAVE
DISTURBANCE IN NORTHWEST FLOW ALOFT AND ITS ASSOCIATED COLD POCKET
OF AIR IN LOW/MID-LEVELS IS CURRENTLY PUSHING INTO SOUTHERN NEW
ENGLAND...WITH DRIER SUBSIDENT FLOW ENTERING INTO THE SAINT
LAWRENCE VALLEY. COMBINATION OF LOSS OF DAYTIME HEATING AND THE
CONTINUED SOUTHEASTWARD MOVEMENT OF THE SHORTWAVE TROUGH SHOULD
CONTINUE TO RESULT IN A DECREASE IN RAIN/SNOW SHOWER COVERAGE AND
SKY COVER OVER THE NEXT FEW HOURS. BY LATE EVENING...WOULD EXPECT
THAT ANY SHOWER ACTIVITY WOULD HAVE ENDED. MAINLY DRY FORECAST
WITH SKIES CONTINUING TO CLEAR OUT DURING THE OVERNIGHT. THERE
COULD BE A FEW SHELTERED VALLEYS AND HOLLOWS THAT MAY SEE SOME
GROUND FOG/MIST BUT WILL LEAVE OUT OF THE FORECAST FOR NOW DUE TO
THE LIMITED EXTENT OF ANY MIST/FOG. NO CHANGES TO LOW TEMPERATURES
FOR THIS EVENING...GENERALLY IN THE 20S TO LOWER 30S.
PREVIOUS NEAR-TERM DISCUSSION ISSUED AT 337 PM EDT FOLLOWS...
MARGINALLY UNSTABLE AIR MASS IN PLACE LATE THIS AFTERNOON (RAP-
BASED LAPS ANALYSIS SHOWS SBCAPE VALUES AROUND 100 J/KG AT 19Z)
WITH TEMPS IN THE UPR 40S IN THE VALLEYS. WEAK UPR TROUGH AND
ASSOCIATED SFC COLD FRONT ACROSS THE ST. LAWRENCE VALLEY WILL
TRANSLATE STEADILY SEWD ACROSS THE NORTH COUNTRY THIS
EVENING...AND ASSOCIATED WEAK SYNOPTIC ASCENT AND INSTABILITY WILL
MAINTAIN SCATTERED CONVECTIVE SHOWERS ALONG AND IN ADVANCE OF THE
FRONT THROUGH 03Z. THEREAFTER...CLEARING IS RATHER SHARP BEHIND
THE SHORTWAVE TROUGH...AND PRECIPITATION SHOULD GENERALLY END. MAY
SEE A FEW LINGERING SNOW SHOWERS THRU 06-09Z ACROSS THE NRN MTNS
WITH 1-2 ACCUMULATION ACROSS THE SUMMITS...BUT SKIES WILL
GRADUALLY CLEAR IN VALLEY LOCATIONS. NW WINDS 5-10 MPH OVERNIGHT
SHOULD PRECLUDE MUCH IN THE WAY OF FOG...BUT CAN/T COMPLETELY RULE
OUT A BIT OF GROUND FOG IN THE SHELTERED VALLEYS DURING THE PRE-
DAWN HOURS. STAYED SLIGHTLY ABOVE GUIDANCE FOR OVERNIGHT
LOWS...MAINLY IN THE LOW 30S ACROSS THE CHAMPLAIN VALLEY AND UPR
20S ELSEWHERE.
&&
.SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 337 PM EDT FRIDAY...MUCH DRIER AIR MASS IN PLACE SATURDAY WITH
SURFACE RIDGE AXIS MOVING IN AND CRESTING OVER THE NORTH COUNTRY
LATE SATURDAY AFTN/EVE. LOOKING AT MOSTLY CLEAR SKIES AND LIGHT
NWLY WINDS. HAVE RAISED HIGH TEMPS 5 DEG FROM MAV/MET BLEND BASED
ON RECENT TRENDS...YIELDING A HIGH AROUND 50F IN BURLINGTON.
OVERALL...A PLEASANT SATURDAY EXPECTED. CLEAR SKIES PERSIST MOST
OF SATURDAY NIGHT WITH GOOD RADIATIONAL COOLING. LIGHT AND
VARIABLE WINDS BECOME LIGHT S-SW ACROSS ST. LAWRENCE COUNTY AND
INTO THE CHAMPLAIN VALLEY LATE AS RIDGE AXIS SLIDES TO THE MAINE
COAST. LOWS AROUND 30F IN THE CHAMPLAIN/ST. LAWRENCE VALLEYS...BUT
WILL LOCALLY DROP TO AROUND 20F IN THE MORE SHELTERED LOCATIONS OF
THE ADIRONDACKS AND NE KINGDOM OF VERMONT GIVEN GOOD RADIATIVE
COOLING SETUP IN THOSE LOCATIONS.
A BREEZY DAY AND MILD DAY IS EXPECTED SUNDAY AS P-GRADIENT
INCREASES. GRADIENT FLOW INCREASES FROM THE SOUTH AS OCCLUDED FRONT
REACHES WRN NY/WRN PA BY 18Z SUNDAY. LOOKING AT 15-25 MPH WITH GUSTS
TO 30 MPH EXPECTED. INCREASING HIGH CLOUDS DURING THE MORNING...THEN
INTRODUCED INCREASING CHANCES FOR RAIN FROM WEST TO EAST DURING THE
AFTN AND EVENING HOURS CONSISTENT WITH MOST OF THE MODEL GUIDANCE
(12Z ECMWF IS A BIT SLOWER). WENT A COULD DEGREES ABOVE MOS
CONSENSUS FOR HIGH TEMPS (MAINLY IN THE MID 50S IN THE VALLEYS).
OCCLUDED FRONT SWINGS THRU 00-06Z MONDAY AND HAVE A PERIOD OF 80-100
POPS WITH SYSTEM BRINGING 0.2-0.4" RAINFALL AMTS MOST SECTIONS.
SHOULD SEE ENOUGH COOLING ACROSS THE NRN ADIRONDACKS FOR A SWITCH TO
SNOW ACROSS THE HIGHER TERRAIN LATE SUNDAY NIGHT WITH LIGHT SNOW
ACCUMULATION POSSIBLE. LOW TEMPS WILL GENERALLY BE IN THE 30S SUNDAY
NIGHT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 337 PM EDT FRIDAY...OCCLUDED FRONT FROM THE ABOVE MENTIONED SYSTEM
SHIFTS EAST OFF THE ATLANTIC COAST MONDAY LEAVING THE CWA IN A
SEMI-DRY SLOT MONDAY MORNING. PRECIPITATION WILL FILL BACK IN
ACROSS THE REGION BY MID-DAY THOUGH AS SURFACE COLD FRONT MOVES IN
ASSOCIATED WITH PARENT LOW MOVING THROUGH SOUTHERN ONTARIO/QUEBEC.
BOUNDARY LAYER PROFILES CONTINUE TO SHOW MAIN PTYPE WILL BE RAIN
THROUGH MONDAY...BUT TRANSITIONS TO SNOW SHOWERS AS THE FRONT
PUSHES THROUGH MONDAY NIGHT. CHANCES FOR SNOW/RAIN SHOWERS
CONTINUE TUESDAY AND WEDNESDAY AS WELL AS UPPER LOW IS SLOW TO
SHIFT EAST ACROSS QUEBEC AND A SERIES OF SHORTWAVES ROTATE AROUND
THE UPPER FLOW. WITH THE COLD CORE UPPER LOW OVER THE REGION AND
STRONG COLD AIR ADVECTION AT THE SURFACE...HIGH TEMPS
TUESDAY/WEDNESDAY WILL BE WELL BELOW NORMAL IN THE 30S. LOOKS LIKE
A FAIRLY COLD NIGHT TOO FOR TUESDAY NIGHT WITH 925-850MB TEMPS IN
THE TEENS BELOW ZERO SUPPORTING LOWS MAINLY IN THE TEENS AND DOWN
INTO THE SINGLE NUMBERS IN THE COLDER HOLLOWS OF THE DACKS (IE
KSLK). PRECIP CHANCES DECREASE GOING INTO WEDNESDAY NIGHT AS HIGH
PRESSURE BUILDS EAST FROM THE GREAT LAKES AND ANOTHER BELOW NORMAL
NIGHT IS EXPECTED WITH LOWS IN THE TEENS TO LOWER 20S. UPPER RIDGE
CRESTS OVER THE NORTH COUNTRY THURSDAY WITH A NICE SPRING DAY
LIKELY WITH SUNNY SKIES AND TEMPS WARMING INTO THE 40S. RIDGE
BREAKS DOWN THOUGH GOING INTO THURSDAY NIGHT AND FRIDAY TURNING
INTO FAIRLY ZONAL FLOW. NO REAL SYSTEMS ON THE OUTLOOK THROUGH
THIS PERIOD BUT WITH WESTERLY FLOW ALOFT WE`LL LIKELY SEE A MIX OF
SUN AND CLOUDS AND TEMPS RUNNING NEAR NORMAL WITH HIGHS IN THE 40S
AND LOWS IN THE 20S TO LOW 30S.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
THROUGH 00Z SUNDAY...ANY LINGERING LIGHT SHOWERS/SPRINKLES ENDING
THIS EVENING AS BKN/OVC VFR CIGS TREND TOWARD SKC AFTER 04-08Z AS
HIGH PRESSURE BUILDS INTO THE REGION. ONLY EXCEPTION AT KSLK
TERMINAL WHERE SOME PESKY MVFR CIGS AROUND FL025 WILL PERSIST
THROUGH 03-05Z. WINDS GENERALLY LIGHT WEST TO NORTHWESTERLY AT 5
KTS OR LESS. WE COULD ALSO SEE SOME PATCHY BR SFC VISIBILITIES
LATER TONIGHT AS LOWER LEVELS NEAR SATURATION...BUT FEEL ENOUGH
MIXING IN THE LOWER LEVELS TO PRECLUDE MENTION AT ANY DISCRETE
TERMINAL AT THIS TIME. AFTER 14Z SATURDAY...CLEAR SKIES AND LIGHT
WEST TO NORTHWESTERLY WINDS OF 5-10 KTS ARE EXPECTED AS
AFOREMENTIONED HIGH PRESSURE BUILDS INTO THE REGION.
OUTLOOK 00Z SUNDAY THROUGH WEDNESDAY...
00Z SUNDAY THROUGH 18Z SUNDAY...VFR CONDITIONS UNDER HIGH
PRESSURE.
18Z SUNDAY THROUGH 12Z WEDNESDAY...FRONTAL SYSTEM MOVING THROUGH SOUTHERN
ONTARIO/QUEBEC WILL BRING LOWERING CEILINGS AND MVFR CONDITIONS IN
SCATTERED RAIN/SNOW SHOWERS.
12Z WEDNESDAY THROUGH 00Z THURSDAY...MVFR TRENDING TO VFR AS HIGH
PRESSURE BUILDS INTO THE REGION.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS/LOCONTO
SHORT TERM...BANACOS
LONG TERM...LAHIFF
AVIATION...JMG/LAHIFF
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
651 PM EDT FRI MAR 29 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE AND ASSOCIATED SURFACE COLD FRONT WILL
SHIFT SOUTHEASTWARD ACROSS THE NORTH COUNTRY DURING THE LATE
AFTERNOON AND EVENING HOURS...BRINGING SCATTERED RAIN SHOWERS AND
HIGHER ELEVATION SNOW SHOWERS. PRECIPITATION WILL END DURING THE
PRE-DAWN HOURS SATURDAY. SURFACE HIGH PRESSURE BUILDS INTO THE
NORTH COUNTRY DURING SATURDAY BRINGING MOSTLY SUNNY SKIES AND
VALLEY TEMPERATURES IN THE UPPER 40S TO LOWER 50S. CLOUDS WILL
INCREASE DURING SUNDAY...WITH THE NEXT FRONTAL SYSTEM BRINGING
RAIN LATE SUNDAY AFTERNOON INTO SUNDAY NIGHT.
&&
.NEAR TERM /UNTIL 7 AM SATURDAY MORNING/...
AS OF 651 PM EDT FRIDAY...RECENT COMPOSITE RADAR IMAGERY SHOWS AN
OVERALL DECREASE IN COVERAGE OF INSTABILITY RAIN/MTN SNOW SHOWERS
ACROSS THE NORTH COUNTRY LATE THIS AFTERNOON. WATER VAPOR IMAGERY
AND RAP OBJECTIVE ANALYSES SUGGEST THE THE WEAK SHORTWAVE
DISTURBANCE IN NORTHWEST FLOW ALOFT AND ITS ASSOCIATED COLD POCKET
OF AIR IN LOW/MID-LEVELS IS CURRENTLY PUSHING INTO SOUTHERN NEW
ENGLAND...WITH DRIER SUBSIDENT FLOW ENTERING INTO THE SAINT
LAWRENCE VALLEY. COMBINATION OF LOSS OF DAYTIME HEATING AND THE
CONTINUED SOUTHEASTWARD MOVEMENT OF THE SHORTWAVE TROUGH SHOULD
CONTINUE TO RESULT IN A DECREASE IN RAIN/SNOW SHOWER COVERAGE AND
SKY COVER OVER THE NEXT FEW HOURS. BY LATE EVENING...WOULD EXPECT
THAT ANY SHOWER ACTIVITY WOULD HAVE ENDED. MAINLY DRY FORECAST
WITH SKIES CONTINUING TO CLEAR OUT DURING THE OVERNIGHT. THERE
COULD BE A FEW SHELTERED VALLEYS AND HOLLOWS THAT MAY SEE SOME
GROUND FOG/MIST BUT WILL LEAVE OUT OF THE FORECAST FOR NOW DUE TO
THE LIMITED EXTENT OF ANY MIST/FOG. NO CHANGES TO LOW TEMPERATURES
FOR THIS EVENING...GENERALLY IN THE 20S TO LOWER 30S.
PREVIOUS NEAR-TERM DISCUSSION ISSUED AT 337 PM EDT FOLLOWS...
MARGINALLY UNSTABLE AIR MASS IN PLACE LATE THIS AFTERNOON (RAP-
BASED LAPS ANALYSIS SHOWS SBCAPE VALUES AROUND 100 J/KG AT 19Z)
WITH TEMPS IN THE UPR 40S IN THE VALLEYS. WEAK UPR TROUGH AND
ASSOCIATED SFC COLD FRONT ACROSS THE ST. LAWRENCE VALLEY WILL
TRANSLATE STEADILY SEWD ACROSS THE NORTH COUNTRY THIS
EVENING...AND ASSOCIATED WEAK SYNOPTIC ASCENT AND INSTABILITY WILL
MAINTAIN SCATTERED CONVECTIVE SHOWERS ALONG AND IN ADVANCE OF THE
FRONT THROUGH 03Z. THEREAFTER...CLEARING IS RATHER SHARP BEHIND
THE SHORTWAVE TROUGH...AND PRECIPITATION SHOULD GENERALLY END. MAY
SEE A FEW LINGERING SNOW SHOWERS THRU 06-09Z ACROSS THE NRN MTNS
WITH 1-2 ACCUMULATION ACROSS THE SUMMITS...BUT SKIES WILL
GRADUALLY CLEAR IN VALLEY LOCATIONS. NW WINDS 5-10 MPH OVERNIGHT
SHOULD PRECLUDE MUCH IN THE WAY OF FOG...BUT CAN/T COMPLETELY RULE
OUT A BIT OF GROUND FOG IN THE SHELTERED VALLEYS DURING THE PRE-
DAWN HOURS. STAYED SLIGHTLY ABOVE GUIDANCE FOR OVERNIGHT
LOWS...MAINLY IN THE LOW 30S ACROSS THE CHAMPLAIN VALLEY AND UPR
20S ELSEWHERE.
&&
.SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 337 PM EDT FRIDAY...MUCH DRIER AIR MASS IN PLACE SATURDAY WITH
SURFACE RIDGE AXIS MOVING IN AND CRESTING OVER THE NORTH COUNTRY
LATE SATURDAY AFTN/EVE. LOOKING AT MOSTLY CLEAR SKIES AND LIGHT
NWLY WINDS. HAVE RAISED HIGH TEMPS 5 DEG FROM MAV/MET BLEND BASED
ON RECENT TRENDS...YIELDING A HIGH AROUND 50F IN BURLINGTON.
OVERALL...A PLEASANT SATURDAY EXPECTED. CLEAR SKIES PERSIST MOST
OF SATURDAY NIGHT WITH GOOD RADIATIONAL COOLING. LIGHT AND
VARIABLE WINDS BECOME LIGHT S-SW ACROSS ST. LAWRENCE COUNTY AND
INTO THE CHAMPLAIN VALLEY LATE AS RIDGE AXIS SLIDES TO THE MAINE
COAST. LOWS AROUND 30F IN THE CHAMPLAIN/ST. LAWRENCE VALLEYS...BUT
WILL LOCALLY DROP TO AROUND 20F IN THE MORE SHELTERED LOCATIONS OF
THE ADIRONDACKS AND NE KINGDOM OF VERMONT GIVEN GOOD RADIATIVE
COOLING SETUP IN THOSE LOCATIONS.
A BREEZY DAY AND MILD DAY IS EXPECTED SUNDAY AS P-GRADIENT
INCREASES. GRADIENT FLOW INCREASES FROM THE SOUTH AS OCCLUDED FRONT
REACHES WRN NY/WRN PA BY 18Z SUNDAY. LOOKING AT 15-25 MPH WITH GUSTS
TO 30 MPH EXPECTED. INCREASING HIGH CLOUDS DURING THE MORNING...THEN
INTRODUCED INCREASING CHANCES FOR RAIN FROM WEST TO EAST DURING THE
AFTN AND EVENING HOURS CONSISTENT WITH MOST OF THE MODEL GUIDANCE
(12Z ECMWF IS A BIT SLOWER). WENT A COULD DEGREES ABOVE MOS
CONSENSUS FOR HIGH TEMPS (MAINLY IN THE MID 50S IN THE VALLEYS).
OCCLUDED FRONT SWINGS THRU 00-06Z MONDAY AND HAVE A PERIOD OF 80-100
POPS WITH SYSTEM BRINGING 0.2-0.4" RAINFALL AMTS MOST SECTIONS.
SHOULD SEE ENOUGH COOLING ACROSS THE NRN ADIRONDACKS FOR A SWITCH TO
SNOW ACROSS THE HIGHER TERRAIN LATE SUNDAY NIGHT WITH LIGHT SNOW
ACCUMULATION POSSIBLE. LOW TEMPS WILL GENERALLY BE IN THE 30S SUNDAY
NIGHT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 337 PM EDT FRIDAY...OCCLUDED FRONT FROM THE ABOVE MENTIONED SYSTEM
SHIFTS EAST OFF THE ATLANTIC COAST MONDAY LEAVING THE CWA IN A
SEMI-DRY SLOT MONDAY MORNING. PRECIPITATION WILL FILL BACK IN
ACROSS THE REGION BY MID-DAY THOUGH AS SURFACE COLD FRONT MOVES IN
ASSOCIATED WITH PARENT LOW MOVING THROUGH SOUTHERN ONTARIO/QUEBEC.
BOUNDARY LAYER PROFILES CONTINUE TO SHOW MAIN PTYPE WILL BE RAIN
THROUGH MONDAY...BUT TRANSITIONS TO SNOW SHOWERS AS THE FRONT
PUSHES THROUGH MONDAY NIGHT. CHANCES FOR SNOW/RAIN SHOWERS
CONTINUE TUESDAY AND WEDNESDAY AS WELL AS UPPER LOW IS SLOW TO
SHIFT EAST ACROSS QUEBEC AND A SERIES OF SHORTWAVES ROTATE AROUND
THE UPPER FLOW. WITH THE COLD CORE UPPER LOW OVER THE REGION AND
STRONG COLD AIR ADVECTION AT THE SURFACE...HIGH TEMPS
TUESDAY/WEDNESDAY WILL BE WELL BELOW NORMAL IN THE 30S. LOOKS LIKE
A FAIRLY COLD NIGHT TOO FOR TUESDAY NIGHT WITH 925-850MB TEMPS IN
THE TEENS BELOW ZERO SUPPORTING LOWS MAINLY IN THE TEENS AND DOWN
INTO THE SINGLE NUMBERS IN THE COLDER HOLLOWS OF THE DACKS (IE
KSLK). PRECIP CHANCES DECREASE GOING INTO WEDNESDAY NIGHT AS HIGH
PRESSURE BUILDS EAST FROM THE GREAT LAKES AND ANOTHER BELOW NORMAL
NIGHT IS EXPECTED WITH LOWS IN THE TEENS TO LOWER 20S. UPPER RIDGE
CRESTS OVER THE NORTH COUNTRY THURSDAY WITH A NICE SPRING DAY
LIKELY WITH SUNNY SKIES AND TEMPS WARMING INTO THE 40S. RIDGE
BREAKS DOWN THOUGH GOING INTO THURSDAY NIGHT AND FRIDAY TURNING
INTO FAIRLY ZONAL FLOW. NO REAL SYSTEMS ON THE OUTLOOK THROUGH
THIS PERIOD BUT WITH WESTERLY FLOW ALOFT WE`LL LIKELY SEE A MIX OF
SUN AND CLOUDS AND TEMPS RUNNING NEAR NORMAL WITH HIGHS IN THE 40S
AND LOWS IN THE 20S TO LOW 30S.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
THROUGH 12Z SATURDAY...GENERALLY VFR CONDITIONS EXPECTED THROUGH
THE NEXT 24 HOURS. WIDESPREAD BKN-OVC VFR DECK THIS AFTERNOON WITH
A SOME ISOLATED SHOWERS OUT THERE ASSOCIATED WITH A WEAK DISTURBANCE
PASSING THROUGH THE FLOW ALOFT. AS THIS EXITS THE REGION TO THE
EAST LATER THIS EVENING AND HIGH PRESSURE BUILDS IN...SKIES WILL
BEGIN TO CLEAR FROM WEST TO EAST AFTER 22Z AT KMSS...AND BY 02/03Z
AT KMPV/KRUT. FOR THE REMAINDER OF THE OVERNIGHT HOURS...GOOD
LIKELIHOOD OF SOME BR FORMING WITH CLEARING SKIES...ABATING WINDS AND
LOTS OF SOIL MOISTURE ACROSS THE REGION. DON`T THINK WE`LL SEE
ANYTHING LOWER THEN MVFR THOUGH AS BOUNDARY LAYER WINDS STAY
AROUND 5-10KTS UP TO 1 KFT. AFTER 14Z...CLEAR SKIES AND LIGHT NW
WINDS OF 5-10 KTS IS EXPECTED FOR SATURDAY.
OUTLOOK 18Z SATURDAY THROUGH WEDNESDAY...
18Z SATURDAY THROUGH 18Z SUNDAY...VFR CONDITIONS UNDER HIGH PRESSURE.
18Z SUNDAY THROUGH 12Z WEDNESDAY...FRONTAL SYSTEM MOVING THROUGH SOUTHERN
ONTARIO/QUEBEC WILL BRING LOWERING CEILINGS AND MVFR CONDITIONS IN
SCATTERED RAIN/SNOW SHOWERS.
12Z WEDNESDAY THROUGH 00Z THURSDAY...MVFR TRENDING TO VFR AS HIGH
PRESSURE BUILDS INTO THE REGION.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS/LOCONTO
SHORT TERM...BANACOS
LONG TERM...LAHIFF
AVIATION...LAHIFF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
106 PM EDT FRI MAR 29 2013
.SYNOPSIS...
SURFACE HIGH PRESSURE WILL CONTINUE TO MOVE SLOWLY EAST THROUGH
SATURDAY. AN UPPER LEVEL DISTURBANCE MOVES THROUGH THE REGION
OVERNIGHT THROUGH EARLY SATURDAY. A WARM FRONT LIFTS NORTH ACROSS
PARTS OF THE CAROLINAS SUNDAY...WITH A WEAK COLD FRONT SWEEPING EAST
OVER THE REGION SUNDAY AFTERNOON AND SUNDAY NIGHT.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 955 AM FRIDAY...
THROUGH TONIGHT:
THE LATEST SURFACE ANALYSIS SHOWED THE SURFACE RIDGE OF HIGH
PRESSURE DIRECTLY OVER CENTRAL NORTH CAROLINA...AND THIS WILL
GRADUALLY MOVE TO THE EAST DURING THE AFTERNOON AS MID-LEVEL
SHORTWAVE APPROACHES THE AREA FROM THE WEST AND NORTHWEST. IR IMAGES
SHOW A SMALL REGION OF COLD-TOPPED CLOUDS ASSOCIATED WITH
PRECIPITATION OVER PARTS OF KENTUCKY AND TENNESSEE...THOUGH GUIDANCE
SUGGESTS THESE CLOUDS SHOULD WARM AND PRECIPITATION WEAKEN AS DRY
AIR IS ENCOUNTERED TO THE EAST. THE MORNING KGSO SOUNDING SHOWED A
PRECIPITABLE WATER VALUE UNDER A QUARTER-INCH...AND CENTRAL NORTH
CAROLINA WAS REGIONALLY THE MINIMUM IN SURFACE THETA-E...ALONG WITH
BUFR SOUNDINGS FROM THE NAM AND THE GFS MAINTAINING A FAIRLY DRY AIR
MASS THROUGH THE AFTERNOON. A LARGE PATCH OF COOL HIGH SC/LOW AC
TOWARD KRZZ AND KETC SHOULD GRADUALLY SHIFT EAST-SOUTHEAST LATE THIS
MORNING AND THIS AFTERNOON IN CONCERT WITH THE LOW-LEVEL MOISTURE
FIELDS OF THE RUC AND NAM...SUCH THAT MOST OF CENTRAL NORTH CAROLINA
WILL SEE CONSIDERABLE SUNSHINE FOR MUCH OF THE DAY. MID-LEVEL CLOUDS
WILL INCREASE LATE...AND WHILE MOISTURE INCREASES IN THE ICE
NUCLEATION ZONE BETWEEN -10C AND -15C VERY LATE TODAY AND ESPECIALLY
THIS EVENING...THE DEPTH OF MOISTURE IS SHALLOW WITH DRY AIR
REMAINING IN THE BOUNDARY LAYER. KEPT HIGH TEMPERATURES AS IS THOUGH
THE IMMEDIATE TRIAD MAY BE ON THE HIGH END OF THE EXPECTED
RANGE...BUT GOOD SUN FOR MUCH OF THE DAY AND WEST WINDS WITH A FEW
GUSTS IN THE LOWER TEENS KTS SHOULD HELP WARM THE AIR MASS.
THE LATEST BUFR SOUNDINGS FROM THE NAM AND THE GFS SUGGEST THAT THE
SOUTHWEST PIEDMONT INTO THE SANDHILLS HAVE A CHANCE OF SPRINKLES
OVERNIGHT. TOWARD KGSO...KRDU...AND KRWI...THE MOISTURE DEPTH
REMAINS SHALLOW...HOWEVER...TOWARD KFAY...ON BOTH MODELS THE DEPTH
OF MOISTURE IS GREATER WITH ALSO GREATER MOISTURE IN THE BOUNDARY
LAYER. WITH QPF FORECAST BY BOTH MODELS AS WELL...FOR NOW HAVE
INTRODUCED SPRINKLES AND MAY HAVE TO INCREASE POPS INTO THE CHANCE
CATEGORY FOR PARTS OF THIS AREA IN SUBSEQUENT FORECASTS...WHICH
COULD LINGER INTO PART OF SATURDAY MORNING. THE INCREASE IN CLOUD
COVER SHOULD LEAD TO WARMER OVERNIGHT LOW TEMPERATURES THAN PREVIOUS
NIGHTS...WITH LOWS GENERALLY IN THE UPPER 30S TO LOWER 40S. -DJF
SATURDAY:
SURFACE HIGH PRESSURE CENTERED TO THE NORTH OF THE AREA SATURDAY
MORNING WILL QUICKLY SHIFT OFFSHORE ON SATURDAY AFTERNOON RESULTING
IN A RENEWED SOUTHERLY/SOUTHWESTERLY RETURN FLOW AFTER A BRIEF
PERIOD OF NORTHERLY SURFACE FLOW BEHIND THE AFOREMENTIONED SURFACE
TROUGH. HOWEVER... GIVEN LINGERING LOW LEVEL MOISTURE BELOW THE
SUBSIDENCE INVERSION AROUND 800 MB ALONG WITH INCREASING MID AND
HIGH CLOUDS IN ADVANCE OF A SYSTEM APPROACHING THE AREA FROM THE
WEST WILL HELP KEEP SKIES PARTLY SUNNY DURING THE AFTERNOON.
AFTERNOON LOW LEVEL THICKNESS VALUES ARE EXPECTED TO BE AROUND 10 TO
15 METERS BELOW NORMAL AT LEAST. THUS... GIVEN THIS AND THE CLOUD
COVER WILL CONTINUE TO TREND FORECAST HIGHS FOR SATURDAY A LITTLE
BIT BELOW STATISTICAL GUIDANCE VALUES. THIS YIELDS HIGH TEMPS IN THE
LOWER TO MID 60S ACROSS THE AREA. -BSD
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 305 AM FRIDAY...
SATURDAY NIGHT INTO SUNDAY...INCREASING LOW LEVEL WAA COUPLED WITH
MODEST MOISTURE TRANSPORT OFF THE NE GULF OF MEXICO AND ATLANTIC
WILL AID IN THE DEVELOPMENT OF SPOTTY RAIN SHOWERS LATE SATURDAY
NIGHT INTO SUNDAY MORNING...MAINLY ACROSS THE SOUTHERN AND WESTERN
SECTIONS OF CENTRAL NC. INCREASING/THICKENING CLOUD COVERAGE AND A
LIGHT SLY SFC WIND WILL RESULT IN MIN TEMPS SATURDAY NIGHT ABOUT 10
DEGREES WARMER THAN TONIGHT. LATER SUNDAY...A WEAK MID LEVEL TROUGH
WILL CROSS THE REGION. THIS FEATURE INTERACTING WITH THE AVAILABLE
MOISTURE AND WEAK INSTABILITY WILL TRIGGER ADDITIONAL SHOWER
ACTIVITY. EXPECT SHOWER COVERAGE TO BE A LITTLE MORE IN THE NORTHERN
PIEDMONT DUE TO CLOSE PROXIMITY OF A STALLED SURFACE BOUNDARY ACROSS
SOUTHERN VA. SHOWER COVERAGE/INTENSITY SHOULD DIMINISH WEST-TO-EAST
BY MID-LATE AFTERNOON AS THE MID LEVEL TROUGH EXITS THE REGION. RAIN
TOTALS APPEAR MEAGER THOUGH DUE TO LACK OF STRONG CONVERGENCE IN THE
LOW-MID LEVELS OF THE ATMOSPHERE. RAINFALL SHOULD TOTAL UNDER A
QUARTER OF AN INCH WITH MOST LOCATIONS MEASURING LESS THAN A TENTH
OF AN INCH. IN SPITE OF CONSIDERABLE CLOUDINESS AND SCATTERED
SHOWERS...MAX TEMPS SUNDAY WILL BE JUST A FEW DEGREES SHY OF
NORMAL...MAINLY IN THE MID-UPPER 60S. IF SHOWER COVERAGE IS MORE
EXTENSIVE THAN CURRENT THINKING...THIS MAY HOLD DOWN TEMPS BY 4-6
DEGREES...ESPECIALLY ACROSS THE NW.
SUNDAY NIGHT AND MONDAY...SUBSIDENCE IN WEAK OF DEPARTING MID LEVEL
TROUGH ALONG WITH MEAN WLY FLOW WILL RESULT IN DECREASING CLOUD
COVERAGE SUNDAY NIGHT INTO MONDAY. RESIDUAL SFC MOISTURE AND
CLEARING SKIES ALOFT MAY ALLOW FOR THE DEVELOPMENT OF PATCHY FOG BY
EARLY MONDAY. A LIGHT SW SFC FLOW ALONG WITH PATCHY CLOUD COVER
SHOULD RESULT IN FAIRLY MILD OVERNIGHT TEMPS (COMPARED TO THE PAST
TWO WEEKS). MIN TEMPS GENERALLY 50-55. A MIXTURE OF CLOUDS/SUN ON
MONDAY PLUS A STEADY SW WIND OCCASIONALLY GUSTING BETWEEN 20-25 MPH
WILL BOOST TEMPS TO NEAR OR SLIGHTLY ABOVE NORMAL (NEAR 70-LOWER
70S). AFTERNOON HEATING MAY TRIGGER A SHOWER OR TWO BUT MOST
LOCATIONS WILL REMAIN DRY.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 305 AM FRIDAY...
MONDAY NIGHT THROUGH TUESDAY NIGHT...A MODERATE TO STRONG S/W IN THE
NORTHERN BRANCH OF POLAR JET CROSSING THE GREAT LAKES WILL AID TO
DRIVE THE STALLED SFC BOUNDARY ACROSS SOUTHERN VA THROUGH
CENTRAL NC LATE MONDAY NIGHT INTO TUESDAY. GFS MUCH QUICKER WITH
THIS FRONTAL MOVEMENT...ABOUT 6-8 HOURS FASTER COMPARED TO THE
ECMWF. ECMWF HAS BACKING OF OTHER MODELS WHILE GFS APPEARS TO BE A
SOUTHERN/EASTERN OUTLIER BY TUESDAY. THUS WILL FAVOR THE SLOWER
FRONTAL ARRIVAL TIME. THIS REQUIRES SOME ADJUSTMENT TO MIN TEMPS
MONDAY NIGHT. WILL RAISE MIN TEMPS ABOUT 5 DEGREES FROM PREVIOUS
FORECAST (WITH THE POTENTIAL FOR MIN TEMPS TO BE AN ADDITIONAL 5-7
DEGREES WARMER). MIN TEMPS UPPER 40S TO LOWER 50S. COOL/MOIST NE
FLOW BEHIND THE BOUNDARY WILL RESULT IN A DREARY DAY TUESDAY WITH
PATCHES OF LIGHT RAIN PROBABLE IN THE HYBRID DAMMING SCENARIO. TEMPS
WILL BE MUCH COOLER (ABOUT 20 DEGREES) COMPARED TO MONDAY WITH
DAYTIME TEMPS 50-55. FOR MANY LOCATIONS...CALENDER DAY HIGH TEMPS
WILL LIKELY OCCUR BETWEEN MIDNIGHT-8 AM. EXPECT IMPROVING
CONDITIONS LATE TUESDAY INTO TUESDAY NIGHT AS SFC FRONT SLIDES
FARTHER AWAY AND MID LEVEL TROUGH CROSSES THE REGION. MIN TEMPS
TUESDAY NIGHT LOW-MID 30S.
WEDNESDAY INTO THURSDAY WILL FEATURE DRY AND COOL CONDITIONS AS
SURFACE HIGH OVER THE CENTRAL U.S. BUILDS INTO THE CAROLINAS AND
BASE OF L/W TROUGH SETTLES OVERHEAD. THICKNESSES WEDNESDAY CLOSE TO
40M BELOW NORMAL WITH A MODEST RECOVERY ON THU. THIS SUGGEST
AFTERNOON TEMPS WELL BELOW NORMAL FOR EARLY APRIL. MAX TEMPS 50-55
WEDNESDAY AND LOW-MID 50S THURSDAY. EXPECT MIN TEMPS EARLY THU IN
THE 30-35 DEGREE RANGE.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 105 PM FRIDAY...
VFR CONDITIONS ARE ANTICIPATED THROUGH THE 18Z VALID TAF PERIOD.
MID-LEVEL CLOUDS WILL INCREASE OVER CENTRAL NORTH CAROLINA...AND AS
AN UPPER-LEVEL DISTURBANCE MOVES INTO AND THROUGH THE REGION LATE
TONIGHT AND EARLY SATURDAY...THERE SHOULD BE AREAS OF LIGHT RAIN
MAINLY TOWARD KFAY. MODEL GUIDANCE SUGGESTS THAT CONDITIONS SHOULD
REMAIN PREDOMINANTLY VFR IN THE LIGHT RAIN...ALTHOUGH THERE IS
CERTAINLY A MODEST CHANCE OF MVFR CONDITIONS IN CLOUDS AND/OR
VISIBILITY AT KFAY MAINLY BETWEEN 10Z AND 16Z SATURDAY.
BEYOND THE 18Z VALID TAF PERIOD...CHANCES FOR ADVERSE AVIATION
CONDITIONS INCLUDING IFR CONDITIONS INCREASE FOR LATE SATURDAY NIGHT
AND SUNDAY MORNING. AHEAD OF A WARM FRONT...THERE IS SOME POTENTIAL
FOR LOW-LEVEL WIND SHEAR AS WELL DURING THE SAME TIME FRAME...WITH
VEERING OF THE WINDS ALOFT AND AN INCREASE IN SPEED THROUGH THE LOW
LEVELS OF THE ATMOSPHERE. A FEW THUNDERSTORMS ARE ALSO POSSIBLE
SUNDAY AHEAD OF A COLD FRONT. BEYOND SUNDAY...THERE IS ANOTHER
CHANCE FOR IFR CONDITIONS OVERNIGHT MONDAY INTO EARLY TUESDAY AHEAD
OF ANOTHER COLD FRONT THAT WILL PUSH THROUGH CENTRAL NORTH CAROLINA.
CONDITIONS ARE MOST LIKELY VFR DURING THE DAY MONDAY...AND AGAIN FOR
WEDNESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF/BSD
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
956 AM EDT FRI MAR 29 2013
.SYNOPSIS...
HIGH PRESSURE WILL MOVE ACROSS THE REGION TODAY AND OFF THE
SOUTHEAST COAST SATURDAY. AN UPPER LEVEL DISTURBANCE APPROACHES FROM
THE WEST LATE TODAY...MOVING THROUGH THE REGION OVERNIGHT AND EARLY
SATURDAY. A FRONTAL SYSTEM WILL APPROACH FROM THE WEST LATE SATURDAY
AND MOVE SLOWLY THROUGH THE AREA SUNDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 955 AM FRIDAY...
THROUGH TONIGHT:
THE LATEST SURFACE ANALYSIS SHOWED THE SURFACE RIDGE OF HIGH
PRESSURE DIRECTLY OVER CENTRAL NORTH CAROLINA...AND THIS WILL
GRADUALLY MOVE TO THE EAST DURING THE AFTERNOON AS MID-LEVEL
SHORTWAVE APPROACHES THE AREA FROM THE WEST AND NORTHWEST. IR IMAGES
SHOW A SMALL REGION OF COLD-TOPPED CLOUDS ASSOCIATED WITH
PRECIPITATION OVER PARTS OF KENTUCKY AND TENNESSEE...THOUGH GUIDANCE
SUGGESTS THESE CLOUDS SHOULD WARM AND PRECIPITATION WEAKEN AS DRY
AIR IS ENCOUNTERED TO THE EAST. THE MORNING KGSO SOUNDING SHOWED A
PRECIPITABLE WATER VALUE UNDER A QUARTER-INCH...AND CENTRAL NORTH
CAROLINA WAS REGIONALLY THE MINIMUM IN SURFACE THETA-E...ALONG WITH
BUFR SOUNDINGS FROM THE NAM AND THE GFS MAINTAINING A FAIRLY DRY AIR
MASS THROUGH THE AFTERNOON. A LARGE PATCH OF COOL HIGH SC/LOW AC
TOWARD KRZZ AND KETC SHOULD GRADUALLY SHIFT EAST-SOUTHEAST LATE THIS
MORNING AND THIS AFTERNOON IN CONCERT WITH THE LOW-LEVEL MOISTURE
FIELDS OF THE RUC AND NAM...SUCH THAT MOST OF CENTRAL NORTH CAROLINA
WILL SEE CONSIDERABLE SUNSHINE FOR MUCH OF THE DAY. MID-LEVEL CLOUDS
WILL INCREASE LATE...AND WHILE MOISTURE INCREASES IN THE ICE
NUCLEATION ZONE BETWEEN -10C AND -15C VERY LATE TODAY AND ESPECIALLY
THIS EVENING...THE DEPTH OF MOISTURE IS SHALLOW WITH DRY AIR
REMAINING IN THE BOUNDARY LAYER. KEPT HIGH TEMPERATURES AS IS THOUGH
THE IMMEDIATE TRIAD MAY BE ON THE HIGH END OF THE EXPECTED
RANGE...BUT GOOD SUN FOR MUCH OF THE DAY AND WEST WINDS WITH A FEW
GUSTS IN THE LOWER TEENS KTS SHOULD HELP WARM THE AIR MASS.
THE LATEST BUFR SOUNDINGS FROM THE NAM AND THE GFS SUGGEST THAT THE
SOUTHWEST PIEDMONT INTO THE SANDHILLS HAVE A CHANCE OF SPRINKLES
OVERNIGHT. TOWARD KGSO...KRDU...AND KRWI...THE MOISTURE DEPTH
REMAINS SHALLOW...HOWEVER...TOWARD KFAY...ON BOTH MODELS THE DEPTH
OF MOISTURE IS GREATER WITH ALSO GREATER MOISTURE IN THE BOUNDARY
LAYER. WITH QPF FORECAST BY BOTH MODELS AS WELL...FOR NOW HAVE
INTRODUCED SPRINKLES AND MAY HAVE TO INCREASE POPS INTO THE CHANCE
CATEGORY FOR PARTS OF THIS AREA IN SUBSEQUENT FORECASTS...WHICH
COULD LINGER INTO PART OF SATURDAY MORNING. THE INCREASE IN CLOUD
COVER SHOULD LEAD TO WARMER OVERNIGHT LOW TEMPERATURES THAN PREVIOUS
NIGHTS...WITH LOWS GENERALLY IN THE UPPER 30S TO LOWER 40S. -DJF
SATURDAY:
SURFACE HIGH PRESSURE CENTERED TO THE NORTH OF THE AREA SATURDAY
MORNING WILL QUICKLY SHIFT OFFSHORE ON SATURDAY AFTERNOON RESULTING
IN A RENEWED SOUTHERLY/SOUTHWESTERLY RETURN FLOW AFTER A BRIEF
PERIOD OF NORTHERLY SURFACE FLOW BEHIND THE AFOREMENTIONED SURFACE
TROUGH. HOWEVER... GIVEN LINGERING LOW LEVEL MOISTURE BELOW THE
SUBSIDENCE INVERSION AROUND 800 MB ALONG WITH INCREASING MID AND
HIGH CLOUDS IN ADVANCE OF A SYSTEM APPROACHING THE AREA FROM THE
WEST WILL HELP KEEP SKIES PARTLY SUNNY DURING THE AFTERNOON.
AFTERNOON LOW LEVEL THICKNESS VALUES ARE EXPECTED TO BE AROUND 10 TO
15 METERS BELOW NORMAL AT LEAST. THUS... GIVEN THIS AND THE CLOUD
COVER WILL CONTINUE TO TREND FORECAST HIGHS FOR SATURDAY A LITTLE
BIT BELOW STATISTICAL GUIDANCE VALUES. THIS YIELDS HIGH TEMPS IN THE
LOWER TO MID 60S ACROSS THE AREA. -BSD
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 305 AM FRIDAY...
SATURDAY NIGHT INTO SUNDAY...INCREASING LOW LEVEL WAA COUPLED WITH
MODEST MOISTURE TRANSPORT OFF THE NE GULF OF MEXICO AND ATLANTIC
WILL AID IN THE DEVELOPMENT OF SPOTTY RAIN SHOWERS LATE SATURDAY
NIGHT INTO SUNDAY MORNING...MAINLY ACROSS THE SOUTHERN AND WESTERN
SECTIONS OF CENTRAL NC. INCREASING/THICKENING CLOUD COVERAGE AND A
LIGHT SLY SFC WIND WILL RESULT IN MIN TEMPS SATURDAY NIGHT ABOUT 10
DEGREES WARMER THAN TONIGHT. LATER SUNDAY...A WEAK MID LEVEL TROUGH
WILL CROSS THE REGION. THIS FEATURE INTERACTING WITH THE AVAILABLE
MOISTURE AND WEAK INSTABILITY WILL TRIGGER ADDITIONAL SHOWER
ACTIVITY. EXPECT SHOWER COVERAGE TO BE A LITTLE MORE IN THE NORTHERN
PIEDMONT DUE TO CLOSE PROXIMITY OF A STALLED SURFACE BOUNDARY ACROSS
SOUTHERN VA. SHOWER COVERAGE/INTENSITY SHOULD DIMINISH WEST-TO-EAST
BY MID-LATE AFTERNOON AS THE MID LEVEL TROUGH EXITS THE REGION. RAIN
TOTALS APPEAR MEAGER THOUGH DUE TO LACK OF STRONG CONVERGENCE IN THE
LOW-MID LEVELS OF THE ATMOSPHERE. RAINFALL SHOULD TOTAL UNDER A
QUARTER OF AN INCH WITH MOST LOCATIONS MEASURING LESS THAN A TENTH
OF AN INCH. IN SPITE OF CONSIDERABLE CLOUDINESS AND SCATTERED
SHOWERS...MAX TEMPS SUNDAY WILL BE JUST A FEW DEGREES SHY OF
NORMAL...MAINLY IN THE MID-UPPER 60S. IF SHOWER COVERAGE IS MORE
EXTENSIVE THAN CURRENT THINKING...THIS MAY HOLD DOWN TEMPS BY 4-6
DEGREES...ESPECIALLY ACROSS THE NW.
SUNDAY NIGHT AND MONDAY...SUBSIDENCE IN WEAK OF DEPARTING MID LEVEL
TROUGH ALONG WITH MEAN WLY FLOW WILL RESULT IN DECREASING CLOUD
COVERAGE SUNDAY NIGHT INTO MONDAY. RESIDUAL SFC MOISTURE AND
CLEARING SKIES ALOFT MAY ALLOW FOR THE DEVELOPMENT OF PATCHY FOG BY
EARLY MONDAY. A LIGHT SW SFC FLOW ALONG WITH PATCHY CLOUD COVER
SHOULD RESULT IN FAIRLY MILD OVERNIGHT TEMPS (COMPARED TO THE PAST
TWO WEEKS). MIN TEMPS GENERALLY 50-55. A MIXTURE OF CLOUDS/SUN ON
MONDAY PLUS A STEADY SW WIND OCCASIONALLY GUSTING BETWEEN 20-25 MPH
WILL BOOST TEMPS TO NEAR OR SLIGHTLY ABOVE NORMAL (NEAR 70-LOWER
70S). AFTERNOON HEATING MAY TRIGGER A SHOWER OR TWO BUT MOST
LOCATIONS WILL REMAIN DRY.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 305 AM FRIDAY...
MONDAY NIGHT THROUGH TUESDAY NIGHT...A MODERATE TO STRONG S/W IN THE
NORTHERN BRANCH OF POLAR JET CROSSING THE GREAT LAKES WILL AID TO
DRIVE THE STALLED SFC BOUNDARY ACROSS SOUTHERN VA THROUGH
CENTRAL NC LATE MONDAY NIGHT INTO TUESDAY. GFS MUCH QUICKER WITH
THIS FRONTAL MOVEMENT...ABOUT 6-8 HOURS FASTER COMPARED TO THE
ECMWF. ECMWF HAS BACKING OF OTHER MODELS WHILE GFS APPEARS TO BE A
SOUTHERN/EASTERN OUTLIER BY TUESDAY. THUS WILL FAVOR THE SLOWER
FRONTAL ARRIVAL TIME. THIS REQUIRES SOME ADJUSTMENT TO MIN TEMPS
MONDAY NIGHT. WILL RAISE MIN TEMPS ABOUT 5 DEGREES FROM PREVIOUS
FORECAST (WITH THE POTENTIAL FOR MIN TEMPS TO BE AN ADDITIONAL 5-7
DEGREES WARMER). MIN TEMPS UPPER 40S TO LOWER 50S. COOL/MOIST NE
FLOW BEHIND THE BOUNDARY WILL RESULT IN A DREARY DAY TUESDAY WITH
PATCHES OF LIGHT RAIN PROBABLE IN THE HYBRID DAMMING SCENARIO. TEMPS
WILL BE MUCH COOLER (ABOUT 20 DEGREES) COMPARED TO MONDAY WITH
DAYTIME TEMPS 50-55. FOR MANY LOCATIONS...CALENDER DAY HIGH TEMPS
WILL LIKELY OCCUR BETWEEN MIDNIGHT-8 AM. EXPECT IMPROVING
CONDITIONS LATE TUESDAY INTO TUESDAY NIGHT AS SFC FRONT SLIDES
FARTHER AWAY AND MID LEVEL TROUGH CROSSES THE REGION. MIN TEMPS
TUESDAY NIGHT LOW-MID 30S.
WEDNESDAY INTO THURSDAY WILL FEATURE DRY AND COOL CONDITIONS AS
SURFACE HIGH OVER THE CENTRAL U.S. BUILDS INTO THE CAROLINAS AND
BASE OF L/W TROUGH SETTLES OVERHEAD. THICKNESSES WEDNESDAY CLOSE TO
40M BELOW NORMAL WITH A MODEST RECOVERY ON THU. THIS SUGGEST
AFTERNOON TEMPS WELL BELOW NORMAL FOR EARLY APRIL. MAX TEMPS 50-55
WEDNESDAY AND LOW-MID 50S THURSDAY. EXPECT MIN TEMPS EARLY THU IN
THE 30-35 DEGREE RANGE.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 620 AM FRIDAY...
24 HOUR TAF PERIOD:
VFR CONDITIONS ARE EXPECTED TO CONTINUE FOR THE 24 HOUR TAF PERIOD.
SURFACE HIGH PRESSURE WILL SLOWLY SLIP TO THE SOUTH AND SOUTHEAST OF
THE AREA TODAY... ALLOWING LIGHT NORTH TO NORTHWESTERLY WINDS THIS
MORNING TO BECOME WEST TO SOUTHWESTERLY BY AFTERNOON IN THE 6 TO 10
KT RANGE... WITH POSSIBLY A FEW GUSTS OF AROUND 15 KTS OR SO DURING
THE AFTERNOON (BEST CHANCE OF ANY WINDS GUSTS AT KINT/KGSO). EXPECT
CLOUD COVER WILL BEGIN TO INCREASE ACROSS THE AREA IN THE MID TO
LATE AFTERNOON AS A WEAK UPPER LEVEL DISTURBANCE APPROACHES THE AREA
ALONG WITH AN ACCOMPANYING WEAK SURFACE TROUGH... WHICH IS EXPECTED
TO MOVE THROUGH THE AREA LATE THIS EVENING INTO EARLY SATURDAY
MORNING... WITH SURFACE HIGH PRESSURE BUILDING INTO THE AREA IN THE
WAKE OF THE SYSTEM. THUS... EXPECT AN INCREASE IN CLOUD COVER (WITH
MOSTLY TO CLOUDY TO EVEN OVERCAST SKIES EXPECTED LATE IN THE DAY
INTO THE OVERNIGHT)... GENERALLY 5 KFT OR ABOVE... TO ACCOMPANY THE
DISTURBANCE.
OUTLOOK:
VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH SATURDAY. LOW
LEVEL MOISTENING WILL OCCUR SATURDAY NIGHT AS THE SURFACE RIDGE
MOVES OFFSHORE... AND SUB-VFR CONDITIONS WITH FOG/STRATUS ARE
EXPECTED TO FORM TOWARD SUNDAY MORNING WITH INCREASE CHANCES FOR
SHOWERS. PERIODS OF SUB-VFR CONDITIONS ALONG WITH PERIODS OF SHOWERS
ARE EXPECTED SUNDAY THROUGH TUESDAY AS A FRONTAL SYSTEM MOVES INTO
THE AREA AND STALLS SOMEWHERE ACROSS THE REGION.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF/BSD
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...BSD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
324 PM CDT FRI MAR 29 2013
.SHORT TERM...
MAIN CHALLENGE FOR THIS FORECAST CONTINUES TO BE PERSISTENT FOG
AND TEMPERATURES. SOUNDINGS CONTINUE TO SHOW STRONG INVERSION NEAR
THE SURFACE WITH LIGHT WINDS...THUS EXPECT AREAS OF FOG TO
CONTINUE IN THE DVL BASIN AND ALONG THE RED RIVER VALLEY.
HOWEVER...WILL LET THE ADVISORY EXPIRE AT 21Z AS MOST AREAS HAVE
IMPROVED.
FOR THIS EVENING INTO TONIGHT...A WAVE ASSOCIATED WITH AN AREA OF
LOW PRESSURE IS EXPECTED TO MOVE ACROSS THE AREA TONIGHT. ANALYSIS
OF THE 295K ISENTROPIC SFC SHOWS DECENT UPGLIDE AND FAVORABLE
CONDENSATION PRESSURE DEFICITS POINTING TOWARD PCPN OVERNIGHT.
FCST SOUNDINGS SHOW A WARM LAYER ALOFT AND IS SUFFICIENTLY DEEP TO
FAVOR -ZR ACROSS THE SRN ZONES AND IS REFLECTED IN THE GRIDS.
FOR SATURDAY...GFS AND ECMWF SHOW GOOD COLD ADVECTION BEHIND THE
FRONT WITH BREEZY CONDITIONS AND EXPECT THE COLD AIR WILL OFFSET
ANY SOLAR. WITH A SIGNIFICANT SNOWPACK OVER THE FA...WILL KEEP
TEMPS A BIT COOLER WITH LITTLE RECOVERY DURING THE DAY.
OTHERWISE...EXPECT LOWS SUNDAY MORNING TO BE NEAR SINGLE DIGITS
ACROSS THE NORTH. THE SFC RIDGE LOOKS TO CROSS THE AREA RAPIDLY
AND RETURN FLOW ON MONDAY WILL HELP TEMPS RECOVER A BIT BUT REMAIN
BELOW SEASONAL AVERAGES. LITTLE PCPN IS EXPECTED FOR THE REMAINDER
OF THE WEEKEND.
.LONG TERM (TUE THRU FRI)...
THROUGH MUCH OF THE EXTENDED PERIOD THE VARIOUS MODELS ARE IN
DECENT AGREEMENT THROUGH MOST OF THIS PERIOD. LIKE THE GFS BLENDED
WITH BC-ECMWF. MODELS DIVERGE ON SOLUTIONS TOWARD THE END OF THE
PERIOD AND BEYOND.
AT THE START OF THE EXTENDED A SHARP TROUGH OVER THE GREAT LAKES
WITH RESULTING NORTHWEST FLOW OVER CWFA. ECMWF/GEM/GFS/DGEX ALL IN
GOOD AGREEMENT WITH SURFACE HIGH NORTH TO SOUTH THROUGH FA. LIGHT
WINDS AND DECREASING CLOUD COVER FORECAST SO HAVE OPTED TO LOWER
MINS TUESDAY MORNING ABOUT 5F...CLOSER TO BC-GRIDS WHICH HAVE BEEN
PERFORMING BETTER.
RETURN FLOW BEGINS BY 00Z WEDNESDAY BUT GUIDANCE SUGGESTS LOW LEVEL
WAA SLOW TO CRANK UP. THEREFORE HAVE LOWERED MAXES ABOUT 2F TO 4F...
AGAIN LEANING ON A BC-BLEND. LOW LEVEL WAA DOES KICK IN PRETTY
STRONGLY BY 12Z WEDNESDAY. WHEN COMBINED WITH APPROACHING SHORTWAVE
...LOW LEVEL LIFT...850-500MB OMEGA AND LOWER COND PRES DEF LIKE
THE IDEA OF SLGHT CHC/CHC POPS. LIKELY A MIX OF RA/SN...PERHAPS ALL
RA AFTERNOON...BUT LIGHT AMOUNTS FORECAST.
MODEST BOUNDARY LAYER TEMPERATURE DROP OF 4C TO 6C FORECAST BETWEEN
WEDNESDAY AND THURSDAY...SO HAVE LOWERED THURSDAY MAXES ACCORDINGLY.
I HAVE ALSO UPPED WIND SPEEDS A TAD AS THE LOW LEVEL CAA APPEARS
FAIRLY IMPRESSIVE ON ALL MODELS.
THIS FORECAST PERIOD ENDS WITH MODEL DIFFERENCES BECOMING MORE
GLARING. WITH RETURN FLOW...INCREASING CLOUDS AND MOISTURE AS STRONG
LOW LEVEL BOUNDARY SET THE STAGE FOR LIGHT -RA/-SN. ECMWF HAS A MORE
PROGRESSIVE AND FARTHER NORTH SYSTEM WHILE GFS MUCH SLOWER AND
FARTHER SOUTH. FOLLOWED GUIDANCE TO PAINT SWATH OF PRECIPITATION
MOVING WEST TO EAST LATE THURSDAY INTO FRIDAY. MADE A RASN MIX
DURING THE OVERNIGHT THURSDAY INTO EARLY FRIDAY.
&&
.AVIATION...
CONDITIONS ARE ALL OVER THE PLACE AS FOG DISSIPATES IN USUAL CHAOTIC
MANNER. WELL DEFINED TONGUE OF IFR CIG/VSBY WITHIN THE RRV FLOOR
SHRINKING FROM OUTSIDE INWARD. BIG QUESTION IS WILL LIFR FOG AND
CIGS REDEVELOP AFTER SUNSET. GFS AND LAMP-MOS RE-EXPAND THE LOW
CLOUDS AFTER 02Z. WILL FOLLOW THE LAMP/GFS MOS AS IT HAS HAD AN OKAY
HANDLE ON THE CONDITIONS. HRRR HAS BEEN TOO EXPANSIVE AND GENERALLY
IGNORED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...DENSE FOG ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR NDZ006>008-
014>016-024-026>030-038-039-049-052>054.
MN...DENSE FOG ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR MNZ001>004-
007-029.
&&
$$
HOPKINS/EWENS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
109 PM CDT FRI MAR 29 2013
.UPDATE...
ISSUED AT 109 PM CDT FRI MAR 29 2013
TRIMMED THE WESTERN FRINGE OF THE DENSE FOG ADVISORY AS
VISIBILITIES HAVE RECENTLY IMPROVED. JAMESTOWN IS STILL REPORTING
ONE QUARTER MILE VISIBILITIES WITH SLOW IMPROVEMENT EXPECTED
THROUGH THE AFTERNOON. AS A RESULT...EXTENDED THE DENSE FOG
ADVISORY FOR THE EXTREME EASTERN CWA UNTIL 4 PM CDT. WILL CONTINUE
TO MONITOR AFTERNOON OBS/TRENDS.
FURTHERMORE...ADDED A SLIGHT CHANCE OF THUNDER SOUTHWEST AS THE
LATEST SHORT RANGE MODELS PROG CAPE APPROACHING 200 J/KG AND
SHOWALTER INDICES APPROACHING ZERO THIS AFTERNOON.
NOT MUCH IF ANY PRECIP ASSOCIATED WITH A SHORTWAVE MOVING ACROSS
THE REGION HAS BEEN REACHING THE GROUND. FURTHERMORE...SURFACE
TEMPS NEAR TIOGA AND STANLEY ARE RIGHT AT 32 DEGREES.
THEREFORE...THINK THE FREEZING RAIN THREAT IS DIMINISHING ACROSS
NORTHWESTERN NORTH DAKOTA. HOWEVER...WILL CONTINUE TO HIGHLIGHT THIS
ACTIVITY WITH SPECIAL WEATHER STATEMENTS.
UPDATE ISSUED AT 1041 AM CDT FRI MAR 29 2013
FOG CONTINUES TO DISSIPATE ACROSS WESTERN AND PORTIONS OF CENTRAL
NORTH DAKOTA THIS MORNING. AS A RESULT...CANCELLED THE DENSE FOG
ADVISORY FOR AREAS ALONG AND WEST OF HIGHWAY 83.
THE KGGW WSR-88D DETECTED AN AREA OF LIGHT PRECIPITATION MOVING
EAST ACROSS NORTHEASTERN MONTANA THIS MORNING. THIS ACTIVITY IS
EXPECTED TO ENTER NORTHWESTERN NORTH DAKOTA LATER THIS MORNING.
HOWEVER...BY THE TIME IT REACHES SAID PORTION OF THE
STATE...SURFACE TEMPS MAY BE NEAR OR ABOVE FREEZING. AS A
RESULT...WILL HOLD OFF ON A FREEZING RAIN ADVISORY FOR NOW. WILL
LIKELY HANDLE THE SITUATION WITH SPECIAL WEATHER STATEMENTS BASED
ON SPOTTER REPORTS. THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE
BEEN SENT.
UPDATE ISSUED AT 645 AM CDT FRI MAR 29 2013
NO MAJOR CHANGES FROM THE CURRENT FORECAST. DENSE FOG REMAINS
ALONG THE MISSOURI RIVER COUNTIES AND ALL POINTS NORTH AND EAST.
DID GET A REPORT OF BREAKS IN THE FOG IN MCLEAN COUNTY...BUT
OVERALL SFC OBS ARE COMING IN AT 1/4SM OR ZERO.
FREEZING RAIN HAS BEEN REPORTED IN GLASGOW MONTANA...AND WILL NEED
TO MONITOR IN CASE A FREEZING RAIN ADVISORY BECOMES NEEDED THIS
MORNING. RIGHT NOW IT IS UNCERTAIN WHERE THE BEST ACCUMULATING
PRECIPITATION WILL FALL OVER MY WEST. THE RAP TAKES IT SOUTH OF
THE MISSOURI RIVER WHILE THE EC AND GEM ARE FARTHER NORTH NEAR
KISN...AND THE NAM BRINGS THE HIGHER QPF OVER MY FAR NORTHWEST
ALONG THE CANADIAN BORDER.
&&
.SHORT TERM...TODAY AND TONIGHT...
ISSUED AT 330 AM CDT FRI MAR 29 2013
THE CHALLENGES OF THE SHORT TERM ARE HOW LONG THE ONGOING DENSE FOG
WILL PERSIST...THE IMPACT OF THE FOG ON TEMPERATURES FOR TODAY AND
THE POTENTIAL FOR ISOLATED THUNDERSTORMS ACROSS THE SOUTHWEST THIS
AFTERNOON WITH A WINTRY MIX NORTH.
THE RAP AND HRRR HAVE HAD A GOOD HANDLE ON THE EVOLUTION OF THE
DENSE FOG ACROSS CENTRAL AND NORTHWEST NORTH DAKOTA THROUGH THE
NIGHT...AND WILL FOLLOW THEIR VISIBILITY FORECASTS FROM THEIR LATEST
RUN (29/04 UTC). THIS WOULD SUGGEST THAT DENSE FOG...ESPECIALLY OVER
THE SNOWPACK MAY HOLD NEAR ONE QUARTER OF A MILE THROUGH 18 UTC.
THIS IS SUPPORTED BY THE OBSERVED FOG TRENDS SEEN ON THURSDAY IN A
SIMILAR ENVIRONMENT. THUS HAVE EXPANDED THE DENSE FOG ADVISORY
THROUGH 18 UTC. WOULD NOT RULE OUT A POSSIBLE EXPANSION IN TIME FOR
PORTIONS OF THE ADVISORY LATER INTO THE AFTERNOON AS MID LEVEL CLOUD
COVER MAY SLOW DOWN THE BURNING OFF OF THE FOG. IN REGARDS TO
TEMPERATURES...WILL USE THE OBSERVED TEMPERATURE PATTERN ON THURSDAY
AS A GUIDE...AND WILL LIMIT HIGHS TO THE UPPER 20S ACROSS MUCH OF
THE SNOWPACK IMPACTED BY FOG. LIKE THURSDAY...THE SNOW AND FOG FREE
SOUTHWEST IS EXPECTED TO WARM INTO THE UPPER 50S TO THE LOWER 60S AS
MIXING INCREASES BEHIND A WEAK TROUGH. STEEP LAPSE RATES THROUGH
MUCH OF THE TROPOSPHERE SUGGESTS DIURNALLY DRIVEN SHOWER ACTIVITY IS
POSSIBLE...WITH ISOLATED THUNDERSTORMS NOT OUT OF THE QUESTION GIVEN
THE COOL TEMPERATURES ALOFT AND STEEP LAPSE RATES SUPPORTING
AFTERNOON ML CAPE VALUES OF 200-400 J/KG. ELSEWHERE IN REGARDS TO
PRECIPITATION TODAY...A WEAK WAVE ACROSS SOUTHWEST SASKATCHEWAN AS
OF 08 UTC WILL PROPAGATE SOUTHEAST THROUGH THE DAY. GIVEN THE WEAK
FORCING AND DRY LOW LEVELS...PRECIPITATION WITH SCATTERED ACTIVITY
WILL BE LIGHT. HOWEVER...WITH A WARM LAYER ALOFT ABOVE THE
SUB-FREEZING SURFACE TEMPERATURES OF THE SNOWPACK...FREEZING RAIN
AND SLEET ARE POSSIBLE.
FOR TONIGHT...BOUNDARY LAYER MIXING ON THE ORDER OF 10 KTS CWA WIDE
IN THE WAKE OF THE AFOREMENTIONED SURFACE TROUGH SHOULD HELP TO KEEP
TEMPERATURES FROM BOTTOMING OUT TOO FAR...WITH SOME STRATUS ALSO
HINTED IN THE 00 UTC DETERMINISTIC GUIDANCE. THUS...FOLLOWED FAIRLY
CLOSELY TO A BLEND OF THE 00 UTC DETERMINISTIC MODEL SUITE FOR LOWS
TONIGHT.
.LONG TERM...SATURDAY THROUGH NEXT FRIDAY...
ISSUED AT 330 AM CDT FRI MAR 29 2013
WILL SEE AN ACTIVE FLOW PATTERN THROUGH THE EASTER HOLIDAY
WEEKEND AS A CLOSED UPPER LOW MOVES SOUTH ACROSS CENTRAL CANADA ON
SATURDAY AND INTO THE GREAT LAKES REGION SUNDAY AND MONDAY.
CYCLONIC FLOW ALOFT WILL BRING SEVERAL EMBEDDED S/WVS ACROSS THE
NORTHERN PLAINS SATURDAY THROUGH SUNDAY AFTERNOON SO WILL
MAINTAIN PRECIP CHANCES. ONLY LIGHT QPF IS DEPICTED. THE UPPER
LOW WILL ALSO BRING A SURGE OF COLDER AIR INTO THE NORTHERN PLAINS
SUNDAY INTO MONDAY.
TEMPERATURES MODERATE BACK TO NORMAL BY MID-WEEK AS THE COLDER AIR
MOVES OFF TO OUR EAST.
WILL MAINTAIN A DRY FORECAST SUNDAY NIGHT THROUGH TUESDAY NIGHT
WITH UPPER LEVEL RIDGING BUILDING ALOFT. FOR MID-WEEK...MODELS
DISAGREEING ON A POTENTIAL CLIPPER IMPACTING THE REGION. OPTED TO
KEEP THE FORECAST DRY. NEXT CHANCE OF PRECIPITATION ARRIVES AT THE
END OF THE WORK WEEK WHEN THE UPPER JET PUSHES SOUTH TO ACROSS FAR
SOUTHERN CANADA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 109 PM CDT FRI MAR 29 2013
VLIFR CONDITIONS IN FOG WILL CONTINUE AT KJMS THROUGH MID-
AFTERNOON. OTHERWISE...ELEVATED SHOWER ACTIVITY WILL CONTINUE TO
PUSH ACROSS THE STATE GENERATING VIRGA FROM MID-LEVEL CLOUDS.
MOISTURE TRAPPED BENEATH HIGH PRESSURE BUILDING INTO THE REGION
TONIGHT MAY GENERATE MVFR CIGS...MAINLY AFTER 06Z SATURDAY. A MIX
OF MVFR/VFR CIGS ARE EXPECTED AREAWIDE SATURDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR NDZ005-013-
023-025-037-048-051.
&&
$$
UPDATE...TM
SHORT TERM...AYD
LONG TERM...NH
AVIATION...TM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1041 AM CDT FRI MAR 29 2013
.UPDATE...
ISSUED AT 1041 AM CDT FRI MAR 29 2013
FOG CONTINUES TO DISSIPATE ACROSS WESTERN AND PORTIONS OF CENTRAL
NORTH DAKOTA THIS MORNING. AS A RESULT...CANCELLED THE DENSE FOG
ADVISORY FOR AREAS ALONG AND WEST OF HIGHWAY 83.
THE KGGW WSR-88D DETECTED AN AREA OF LIGHT PRECIPITATION MOVING
EAST ACROSS NORTHEASTERN MONTANA THIS MORNING. THIS ACTIVITY IS
EXPECTED TO ENTER NORTHWESTERN NORTH DAKOTA LATER THIS MORNING.
HOWEVER...BY THE TIME IT REACHES SAID PORTION OF THE
STATE...SURFACE TEMPS MAY BE NEAR OR ABOVE FREEZING. AS A
RESULT...WILL HOLD OFF ON A FREEZING RAIN ADVISORY FOR NOW. WILL
LIKELY HANDLE THE SITUATION WITH SPECIAL WEATHER STATEMENTS BASED
ON SPOTTER REPORTS. THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE
BEEN SENT.
UPDATE ISSUED AT 645 AM CDT FRI MAR 29 2013
NO MAJOR CHANGES FROM THE CURRENT FORECAST. DENSE FOG REMAINS
ALONG THE MISSOURI RIVER COUNTIES AND ALL POINTS NORTH AND EAST.
DID GET A REPORT OF BREAKS IN THE FOG IN MCLEAN COUNTY...BUT
OVERALL SFC OBS ARE COMING IN AT 1/4SM OR ZERO.
FREEZING RAIN HAS BEEN REPORTED IN GLASGOW MONTANA...AND WILL NEED
TO MONITOR IN CASE A FREEZING RAIN ADVISORY BECOMES NEEDED THIS
MORNING. RIGHT NOW IT IS UNCERTAIN WHERE THE BEST ACCUMULATING
PRECIPITATION WILL FALL OVER MY WEST. THE RAP TAKES IT SOUTH OF
THE MISSOURI RIVER WHILE THE EC AND GEM ARE FARTHER NORTH NEAR
KISN...AND THE NAM BRINGS THE HIGHER QPF OVER MY FAR NORTHWEST
ALONG THE CANADIAN BORDER.
&&
.SHORT TERM...TODAY AND TONIGHT...
ISSUED AT 330 AM CDT FRI MAR 29 2013
THE CHALLENGES OF THE SHORT TERM ARE HOW LONG THE ONGOING DENSE FOG
WILL PERSIST...THE IMPACT OF THE FOG ON TEMPERATURES FOR TODAY AND
THE POTENTIAL FOR ISOLATED THUNDERSTORMS ACROSS THE SOUTHWEST THIS
AFTERNOON WITH A WINTRY MIX NORTH.
THE RAP AND HRRR HAVE HAD A GOOD HANDLE ON THE EVOLUTION OF THE
DENSE FOG ACROSS CENTRAL AND NORTHWEST NORTH DAKOTA THROUGH THE
NIGHT...AND WILL FOLLOW THEIR VISIBILITY FORECASTS FROM THEIR LATEST
RUN (29/04 UTC). THIS WOULD SUGGEST THAT DENSE FOG...ESPECIALLY OVER
THE SNOWPACK MAY HOLD NEAR ONE QUARTER OF A MILE THROUGH 18 UTC.
THIS IS SUPPORTED BY THE OBSERVED FOG TRENDS SEEN ON THURSDAY IN A
SIMILAR ENVIRONMENT. THUS HAVE EXPANDED THE DENSE FOG ADVISORY
THROUGH 18 UTC. WOULD NOT RULE OUT A POSSIBLE EXPANSION IN TIME FOR
PORTIONS OF THE ADVISORY LATER INTO THE AFTERNOON AS MID LEVEL CLOUD
COVER MAY SLOW DOWN THE BURNING OFF OF THE FOG. IN REGARDS TO
TEMPERATURES...WILL USE THE OBSERVED TEMPERATURE PATTERN ON THURSDAY
AS A GUIDE...AND WILL LIMIT HIGHS TO THE UPPER 20S ACROSS MUCH OF
THE SNOWPACK IMPACTED BY FOG. LIKE THURSDAY...THE SNOW AND FOG FREE
SOUTHWEST IS EXPECTED TO WARM INTO THE UPPER 50S TO THE LOWER 60S AS
MIXING INCREASES BEHIND A WEAK TROUGH. STEEP LAPSE RATES THROUGH
MUCH OF THE TROPOSPHERE SUGGESTS DIURNALLY DRIVEN SHOWER ACTIVITY IS
POSSIBLE...WITH ISOLATED THUNDERSTORMS NOT OUT OF THE QUESTION GIVEN
THE COOL TEMPERATURES ALOFT AND STEEP LAPSE RATES SUPPORTING
AFTERNOON ML CAPE VALUES OF 200-400 J/KG. ELSEWHERE IN REGARDS TO
PRECIPITATION TODAY...A WEAK WAVE ACROSS SOUTHWEST SASKATCHEWAN AS
OF 08 UTC WILL PROPAGATE SOUTHEAST THROUGH THE DAY. GIVEN THE WEAK
FORCING AND DRY LOW LEVELS...PRECIPITATION WITH SCATTERED ACTIVITY
WILL BE LIGHT. HOWEVER...WITH A WARM LAYER ALOFT ABOVE THE
SUB-FREEZING SURFACE TEMPERATURES OF THE SNOWPACK...FREEZING RAIN
AND SLEET ARE POSSIBLE.
FOR TONIGHT...BOUNDARY LAYER MIXING ON THE ORDER OF 10 KTS CWA WIDE
IN THE WAKE OF THE AFOREMENTIONED SURFACE TROUGH SHOULD HELP TO KEEP
TEMPERATURES FROM BOTTOMING OUT TOO FAR...WITH SOME STRATUS ALSO
HINTED IN THE 00 UTC DETERMINISTIC GUIDANCE. THUS...FOLLOWED FAIRLY
CLOSELY TO A BLEND OF THE 00 UTC DETERMINISTIC MODEL SUITE FOR LOWS
TONIGHT.
.LONG TERM...SATURDAY THROUGH NEXT FRIDAY...
ISSUED AT 330 AM CDT FRI MAR 29 2013
WILL SEE AN ACTIVE FLOW PATTERN THROUGH THE EASTER HOLIDAY
WEEKEND AS A CLOSED UPPER LOW MOVES SOUTH ACROSS CENTRAL CANADA ON
SATURDAY AND INTO THE GREAT LAKES REGION SUNDAY AND MONDAY.
CYCLONIC FLOW ALOFT WILL BRING SEVERAL EMBEDDED S/WVS ACROSS THE
NORTHERN PLAINS SATURDAY THROUGH SUNDAY AFTERNOON SO WILL
MAINTAIN PRECIP CHANCES. ONLY LIGHT QPF IS DEPICTED. THE UPPER
LOW WILL ALSO BRING A SURGE OF COLDER AIR INTO THE NORTHERN PLAINS
SUNDAY INTO MONDAY.
TEMPERATURES MODERATE BACK TO NORMAL BY MID-WEEK AS THE COLDER AIR
MOVES OFF TO OUR EAST.
WILL MAINTAIN A DRY FORECAST SUNDAY NIGHT THROUGH TUESDAY NIGHT
WITH UPPER LEVEL RIDGING BUILDING ALOFT. FOR MID-WEEK...MODELS
DISAGREEING ON A POTENTIAL CLIPPER IMPACTING THE REGION. OPTED TO
KEEP THE FORECAST DRY. NEXT CHANCE OF PRECIPITATION ARRIVES AT THE
END OF THE WORK WEEK WHEN THE UPPER JET PUSHES SOUTH TO ACROSS FAR
SOUTHERN CANADA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 645 AM CDT FRI MAR 29 2013
VLIFR CONDITIONS IN FOG WILL CONTINUE AT KMOT AND KJMS THROUGH AT
LEAST 18 UTC FRIDAY...WITH SLOW IMPROVEMENT THEREAFTER. VLIFR FOG AT
KBIS SHOULD BURN OFF A BIT FASTER...IN THE 15-17 UTC TIMEFRAME
WITH THE LACK OF A DEEP SNOWPACK. KISN AND KDIK HAVE REMAINED ON THE
FRINGE OF THE FOG BANK THUS FAR TONIGHT...AND ARE EXPECTED TO
THROUGH FRIDAY MORNING. THAT SAID...TEMPORARY REDUCTIONS TO IFR
CANNOT BE RULED OUT. SCATTERED PRECIPITATION POSSIBLY IN THE FORM OF
FREEZING RAIN OR SLEET MAY IMPACT KISN AND KMOT...AND POSSIBLY KJMS
FRIDAY EVENING. SCATTERED SHOWERS WITH POSSIBLY AN ISOLATED
THUNDERSTORM IS POSSIBLE NEAR KDIK FRIDAY AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR NDZ004-005-
012-013-022-023-025-036-037-047-048-050-051.
&&
$$
UPDATE...TM
SHORT TERM...AYD
LONG TERM...NH
AVIATION...AYD/NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
645 AM CDT FRI MAR 29 2013
.UPDATE...
ISSUED AT 645 AM CDT FRI MAR 29 2013
NO MAJOR CHANGES FROM THE CURRENT FORECAST. DENSE FOG REMAINS
ALONG THE MISSOURI RIVER COUNTIES AND ALL POINTS NORTH AND EAST.
DID GET A REPORT OF BREAKS IN THE FOG IN MCLEAN COUNTY...BUT
OVERALL SFC OBS ARE COMING IN AT 1/4SM OR ZERO.
FREEZING RAIN HAS BEEN REPORTED IN GLASGOW MONTANA...AND WILL NEED
TO MONITOR IN CASE A FREEZING RAIN ADVISORY BECOMES NEEDED THIS
MORNING. RIGHT NOW IT IS UNCERTAIN WHERE THE BEST ACCUMULATING
PRECIPITATION WILL FALL OVER MY WEST. THE RAP TAKES IT SOUTH OF
THE MISSOURI RIVER WHILE THE EC AND GEM ARE FARTHER NORTH NEAR
KISN...AND THE NAM BRINGS THE HIGHER QPF OVER MY FAR NORTHWEST
ALONG THE CANADIAN BORDER.
&&
.SHORT TERM...TODAY AND TONIGHT...
ISSUED AT 330 AM CDT FRI MAR 29 2013
THE CHALLENGES OF THE SHORT TERM ARE HOW LONG THE ONGOING DENSE FOG
WILL PERSIST...THE IMPACT OF THE FOG ON TEMPERATURES FOR TODAY AND
THE POTENTIAL FOR ISOLATED THUNDERSTORMS ACROSS THE SOUTHWEST THIS
AFTERNOON WITH A WINTRY MIX NORTH.
THE RAP AND HRRR HAVE HAD A GOOD HANDLE ON THE EVOLUTION OF THE
DENSE FOG ACROSS CENTRAL AND NORTHWEST NORTH DAKOTA THROUGH THE
NIGHT...AND WILL FOLLOW THEIR VISIBILITY FORECASTS FROM THEIR LATEST
RUN (29/04 UTC). THIS WOULD SUGGEST THAT DENSE FOG...ESPECIALLY OVER
THE SNOWPACK MAY HOLD NEAR ONE QUARTER OF A MILE THROUGH 18 UTC.
THIS IS SUPPORTED BY THE OBSERVED FOG TRENDS SEEN ON THURSDAY IN A
SIMILAR ENVIRONMENT. THUS HAVE EXPANDED THE DENSE FOG ADVISORY
THROUGH 18 UTC. WOULD NOT RULE OUT A POSSIBLE EXPANSION IN TIME FOR
PORTIONS OF THE ADVISORY LATER INTO THE AFTERNOON AS MID LEVEL CLOUD
COVER MAY SLOW DOWN THE BURNING OFF OF THE FOG. IN REGARDS TO
TEMPERATURES...WILL USE THE OBSERVED TEMPERATURE PATTERN ON THURSDAY
AS A GUIDE...AND WILL LIMIT HIGHS TO THE UPPER 20S ACROSS MUCH OF
THE SNOWPACK IMPACTED BY FOG. LIKE THURSDAY...THE SNOW AND FOG FREE
SOUTHWEST IS EXPECTED TO WARM INTO THE UPPER 50S TO THE LOWER 60S AS
MIXING INCREASES BEHIND A WEAK TROUGH. STEEP LAPSE RATES THROUGH
MUCH OF THE TROPOSPHERE SUGGESTS DIURNALLY DRIVEN SHOWER ACTIVITY IS
POSSIBLE...WITH ISOLATED THUNDERSTORMS NOT OUT OF THE QUESTION GIVEN
THE COOL TEMPERATURES ALOFT AND STEEP LAPSE RATES SUPPORTING
AFTERNOON ML CAPE VALUES OF 200-400 J/KG. ELSEWHERE IN REGARDS TO
PRECIPITATION TODAY...A WEAK WAVE ACROSS SOUTHWEST SASKATCHEWAN AS
OF 08 UTC WILL PROPAGATE SOUTHEAST THROUGH THE DAY. GIVEN THE WEAK
FORCING AND DRY LOW LEVELS...PRECIPITATION WITH SCATTERED ACTIVITY
WILL BE LIGHT. HOWEVER...WITH A WARM LAYER ALOFT ABOVE THE
SUB-FREEZING SURFACE TEMPERATURES OF THE SNOWPACK...FREEZING RAIN
AND SLEET ARE POSSIBLE.
FOR TONIGHT...BOUNDARY LAYER MIXING ON THE ORDER OF 10 KTS CWA WIDE
IN THE WAKE OF THE AFOREMENTIONED SURFACE TROUGH SHOULD HELP TO KEEP
TEMPERATURES FROM BOTTOMING OUT TOO FAR...WITH SOME STRATUS ALSO
HINTED IN THE 00 UTC DETERMINISTIC GUIDANCE. THUS...FOLLOWED FAIRLY
CLOSELY TO A BLEND OF THE 00 UTC DETERMINISTIC MODEL SUITE FOR LOWS
TONIGHT.
.LONG TERM...SATURDAY THROUGH NEXT FRIDAY...
ISSUED AT 330 AM CDT FRI MAR 29 2013
WILL SEE AN ACTIVE FLOW PATTERN THROUGH THE EASTER HOLIDAY
WEEKEND AS A CLOSED UPPER LOW MOVES SOUTH ACROSS CENTRAL CANADA ON
SATURDAY AND INTO THE GREAT LAKES REGION SUNDAY AND MONDAY.
CYCLONIC FLOW ALOFT WILL BRING SEVERAL EMBEDDED S/WVS ACROSS THE
NORTHERN PLAINS SATURDAY THROUGH SUNDAY AFTERNOON SO WILL
MAINTAIN PRECIP CHANCES. ONLY LIGHT QPF IS DEPICTED. THE UPPER
LOW WILL ALSO BRING A SURGE OF COLDER AIR INTO THE NORTHERN PLAINS
SUNDAY INTO MONDAY.
TEMPERATURES MODERATE BACK TO NORMAL BY MID-WEEK AS THE COLDER AIR
MOVES OFF TO OUR EAST.
WILL MAINTAIN A DRY FORECAST SUNDAY NIGHT THROUGH TUESDAY NIGHT
WITH UPPER LEVEL RIDGING BUILDING ALOFT. FOR MID-WEEK...MODELS
DISAGREEING ON A POTENTIAL CLIPPER IMPACTING THE REGION. OPTED TO
KEEP THE FORECAST DRY. NEXT CHANCE OF PRECIPITATION ARRIVES AT THE
END OF THE WORK WEEK WHEN THE UPPER JET PUSHES SOUTH TO ACROSS FAR
SOUTHERN CANADA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 645 AM CDT FRI MAR 29 2013
VLIFR CONDITIONS IN FOG WILL CONTINUE AT KMOT AND KJMS THROUGH AT
LEAST 18 UTC FRIDAY...WITH SLOW IMPROVEMENT THEREAFTER. VLIFR FOG AT
KBIS SHOULD BURN OFF A BIT FASTER...IN THE 15-17 UTC TIMEFRAME
WITH THE LACK OF A DEEP SNOWPACK. KISN AND KDIK HAVE REMAINED ON THE
FRINGE OF THE FOG BANK THUS FAR TONIGHT...AND ARE EXPECTED TO
THROUGH FRIDAY MORNING. THAT SAID...TEMPORARY REDUCTIONS TO IFR
CANNOT BE RULED OUT. SCATTERED PRECIPITATION POSSIBLY IN THE FORM OF
FREEZING RAIN OR SLEET MAY IMPACT KISN AND KMOT...AND POSSIBLY KJMS
FRIDAY EVENING. SCATTERED SHOWERS WITH POSSIBLY AN ISOLATED
THUNDERSTORM IS POSSIBLE NEAR KDIK FRIDAY AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 1 PM CDT /NOON MDT/ THIS AFTERNOON FOR
NDZ001>005-009>013-019>023-025-034>037-042-045>048-050-051.
&&
$$
UPDATE...NH
AVIATION...AYD/NH
SHORT TERM...AYD
LONG TERM...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
331 AM CDT FRI MAR 29 2013
.SHORT TERM...TODAY AND TONIGHT...
ISSUED AT 330 AM CDT FRI MAR 29 2013
THE CHALLENGES OF THE SHORT TERM ARE HOW LONG THE ONGOING DENSE FOG
WILL PERSIST...THE IMPACT OF THE FOG ON TEMPERATURES FOR TODAY AND
THE POTENTIAL FOR ISOLATED THUNDERSTORMS ACROSS THE SOUTHWEST THIS
AFTERNOON WITH A WINTRY MIX NORTH.
THE RAP AND HRRR HAVE HAD A GOOD HANDLE ON THE EVOLUTION OF THE
DENSE FOG ACROSS CENTRAL AND NORTHWEST NORTH DAKOTA THROUGH THE
NIGHT...AND WILL FOLLOW THEIR VISIBILITY FORECASTS FROM THEIR LATEST
RUN (29/04 UTC). THIS WOULD SUGGEST THAT DENSE FOG...ESPECIALLY OVER
THE SNOWPACK MAY HOLD NEAR ONE QUARTER OF A MILE THROUGH 18 UTC.
THIS IS SUPPORTED BY THE OBSERVED FOG TRENDS SEEN ON THURSDAY IN A
SIMILAR ENVIRONMENT. THUS HAVE EXPANDED THE DENSE FOG ADVISORY
THROUGH 18 UTC. WOULD NOT RULE OUT A POSSIBLE EXPANSION IN TIME FOR
PORTIONS OF THE ADVISORY LATER INTO THE AFTERNOON AS MID LEVEL CLOUD
COVER MAY SLOW DOWN THE BURNING OFF OF THE FOG. IN REGARDS TO
TEMPERATURES...WILL USE THE OBSERVED TEMPERATURE PATTERN ON THURSDAY
AS A GUIDE...AND WILL LIMIT HIGHS TO THE UPPER 20S ACROSS MUCH OF
THE SNOWPACK IMPACTED BY FOG. LIKE THURSDAY...THE SNOW AND FOG FREE
SOUTHWEST IS EXPECTED TO WARM INTO THE UPPER 50S TO THE LOWER 60S AS
MIXING INCREASES BEHIND A WEAK TROUGH. STEEP LAPSE RATES THROUGH
MUCH OF THE TROPOSPHERE SUGGESTS DIURNALLY DRIVEN SHOWER ACTIVITY IS
POSSIBLE...WITH ISOLATED THUNDERSTORMS NOT OUT OF THE QUESTION GIVEN
THE COOL TEMPERATURES ALOFT AND STEEP LAPSE RATES SUPPORTING
AFTERNOON ML CAPE VALUES OF 200-400 J/KG. ELSEWHERE IN REGARDS TO
PRECIPITATION TODAY...A WEAK WAVE ACROSS SOUTHWEST SASKATCHEWAN AS
OF 08 UTC WILL PROPAGATE SOUTHEAST THROUGH THE DAY. GIVEN THE WEAK
FORCING AND DRY LOW LEVELS...PRECIPITATION WITH SCATTERED ACTIVITY
WILL BE LIGHT. HOWEVER...WITH A WARM LAYER ALOFT ABOVE THE
SUB-FREEZING SURFACE TEMPERATURES OF THE SNOWPACK...FREEZING RAIN
AND SLEET ARE POSSIBLE.
FOR TONIGHT...BOUNDARY LAYER MIXING ON THE ORDER OF 10 KTS CWA WIDE
IN THE WAKE OF THE AFOREMENTIONED SURFACE TROUGH SHOULD HELP TO KEEP
TEMPERATURES FROM BOTTOMING OUT TOO FAR...WITH SOME STRATUS ALSO
HINTED IN THE 00 UTC DETERMINISTIC GUIDANCE. THUS...FOLLOWED FAIRLY
CLOSELY TO A BLEND OF THE 00 UTC DETERMINISTIC MODEL SUITE FOR LOWS
TONIGHT.
.LONG TERM...SATURDAY THROUGH NEXT FRIDAY...
ISSUED AT 330 AM CDT FRI MAR 29 2013
WILL SEE AN ACTIVE FLOW PATTERN THROUGH THE EASTER HOLIDAY
WEEKEND AS A CLOSED UPPER LOW MOVES SOUTH ACROSS CENTRAL CANADA ON
SATURDAY AND INTO THE GREAT LAKES REGION SUNDAY AND MONDAY.
CYCLONIC FLOW ALOFT WILL BRING SEVERAL EMBEDDED S/WVS ACROSS THE
NORTHERN PLAINS SATURDAY THROUGH SUNDAY AFTERNOON SO WILL
MAINTAIN PRECIP CHANCES. ONLY LIGHT QPF IS DEPICTED. THE UPPER
LOW WILL ALSO BRING A SURGE OF COLDER AIR INTO THE NORTHERN PLAINS
SUNDAY INTO MONDAY.
TEMPERATURES MODERATE BACK TO NORMAL BY MID-WEEK AS THE COLDER AIR
MOVES OFF TO OUR EAST.
WILL MAINTAIN A DRY FORECAST SUNDAY NIGHT THROUGH TUESDAY NIGHT
WITH UPPER LEVEL RIDGING BUILDING ALOFT. FOR MID-WEEK...MODELS
DISAGREEING ON A POTENTIAL CLIPPER IMPACTING THE REGION. OPTED TO
KEEP THE FORECAST DRY. NEXT CHANCE OF PRECIPITATION ARRIVES AT THE
END OF THE WORK WEEK WHEN THE UPPER JET PUSHES SOUTH TO ACROSS FAR
SOUTHERN CANADA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 330 AM CDT FRI MAR 29 2013
VLIFR CONDITIONS IN FOG WILL CONTINUE AT KMOT AND KJMS THROUGH AT
LEAST 18 UTC FRIDAY...WITH SLOW IMPROVEMENT THEREAFTER. VLIFR FOG AT
KBIS SHOULD BURN OFF A BIT FASTER...IN THE 15-17 UTC TIMEFRAME
WITH THE LACK OF A DEEP SNOWPACK. KISN AND KDIK HAVE REMAINED ON THE
FRINGE OF THE FOG BANK THUS FAR TONIGHT...AND ARE EXPECTED TO
THROUGH FRIDAY MORNING. THAT SAID...TEMPORARY REDUCTIONS TO IFR
CANNOT BE RULED OUT. SCATTERED PRECIPITATION POSSIBLY IN THE FORM OF
FREEZING RAIN OR SLEET MAY IMPACT KISN AND KMOT...AND POSSIBLY KJMS
FRIDAY EVENING. SCATTERED SHOWERS WITH POSSIBLY AN ISOLATED
THUNDERSTORM IS POSSIBLE NEAR KDIK FRIDAY AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CDT /9 AM MDT/ THIS MORNING FOR
NDZ001>005-009>013-019>023-025-034>037-042-045>048-050-051.
&&
$$
SHORT TERM/AVIATION...AYD
LONG TERM...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1251 AM CDT FRI MAR 29 2013
.UPDATE...
ISSUED AT 1240 AM CDT FRI MAR 29 2013
BASED UPON WEBCAMS AND SURFACE OBSERVATIONS THROUGH 0530
UTC...EXPANDED THE DENSE FOG ADVISORY INTO DICKEY...LAMOURE...
MCINTOSH...MORTON...MERCER...GRANT...OLIVER AND SIOUX COUNTIES.
THE HRRR THROUGH THE NIGHT HAS CONSISTENTLY BEEN HANDLING THE
EVOLUTION OF THE FOG WELL...WHICH CONTINUES WITH ITS LATEST 02 UTC
RUN. BASED ON THE HRRR...MAY HAVE TO EXTEND THE ADVISORY PAST 15
UTC...ESPECIALLY OVER THE SNOWPACK WITH THE NEXT UPDATE IF ITS
FORECAST TRENDS CONTINUE.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 314 PM CDT THU MAR 28 2013
THE MAIN FORECAST CHALLENGE FOR THE SHORT TERM IS FOG TONIGHT AND
MIXED PRECIPITATION FOR LATE TONIGHT AND FRIDAY.
FOG HAD BEEN PROBLEMATIC TODAY AS THE CURRENT SNOW PACK MAINLY NORTH
AND EAST OF THE MISSOURI RIVER WAS PROVIDING LOW LEVEL MOISTURE AND
KEEPING THE SURFACE LAYER COOLER. ADDING TO THE COMPLEXITY WAS THE
EAST/NORTH LIGHT WIND FLOW WHICH MOVES UP IN ELEVATION ALONG THE
COTEAU OVER NORTHERN NORTH DAKOTA TO SOUTH AND WEST OF
JAMESTOWN...COOLING JUST ENOUGH TO KEEP LOW CLOUDS AND FOG IN THE
AREA. ONLY AROUND 1-2 PM CDT WAS SIGNIFICANT DISSIPATION OF THE FOG
LAYER EVIDENT ON SATELLITE. SOME LINGERING PATCHY DENSE FOG
CONTINUED AT MINOT TO HARVEY/CARRINGTON/RUGBY AT 2 PM.
ABOVE THE SURFACE BOUNDARY LAYER THROUGH H850...SIGNIFICANT WARM
ADVECTION WAS MOVING IN FROM SOUTHWEST TO NORTHEAST ACROSS THE
REGION. HAD EXPECTED THE FOG TO DISSIPATE EARLIER BASED ON
THIS...BUT IT WAS DELAYED BY THE SNOW PACK AND COTEAU INFLUENCES
MENTIONED ABOVE. AS THE FOG AND LOW CLOUDS DISSIPATE...THE WARM
ADVECTION FROM ABOVE THE BOUNDARY LAYER SHOULD BECOME MORE
WELL-ESTABLISHED WHICH SHOULD ACT TO KEEP FOG FROM RE-DEVELOPING.
HOWEVER...WITH SUNSET APPROACHING TEMPERATURES WILL FALL AND THE
THREAT FOR RE-DEVELOPMENT OF FOG OVER THE SNOW PACK RISES. THUS THE
PROBLEM FOR TONIGHT IS WHERE/WHEN/HOW DENSE ANY FOG WILL RE-DEVELOP
- IN OTHER WORDS WHICH FORCES WILL WIN OUT.
THUS REGARDING FOG TONIGHT - HAVE A MENTION OF
PATCHY/AREAS/WIDESPREAD FOG MAINLY OVER THE SNOW PACK THROUGH MID
MORNING ON FRIDAY.
NEXT ATTENTION TURNS TO THE UPPER LEVEL SHORTWAVE TO BRING SOME
LIGHT PRECIPITATION TO THE AREA. LATEST SATELLITE IMAGERY INDICATES
THE SHORTWAVE IS OVER SOUTHERN ALBERTA/SASKATCHEWAN. THIS SHORTWAVE
IS PROGGED TO REACH WESTERN NORTH DAKOTA AROUND MIDNIGHT AND SPREAD
EASTWARD ACROSS THE STATE ON FRIDAY. TEMPERATURE PROFILES FROM
FORECAST SOUNDINGS INDICATE A STRONG WARM LAYER ALOFT AT H850
MENTIONED ABOVE. THESE FACTORS RESULT IN EXPECTED PRECIPITATION TO
BE IN THE FORM OF FREEZING RAIN OR SLEET IN THE NORTHWEST AND
FREEZING RAIN SOUTHWEST AFTER MIDNIGHT THROUGH DAYBREAK.
PRECIPITATION SPREADS EASTWARD ON FRIDAY...MAINLY IN THE FORM OF
RAIN IN THE SOUTHWEST AND FAR SOUTH CENTRAL BY LATE
MORNING/AFTERNOON...AND IN THE FORM OF A WINTRY MIX ACROSS THE
NORTHWEST AND NORTH CENTRAL. LIGHT AMOUNTS OF ONLY A FEW HUNDREDTHS
UP TO A TENTH OF AN INCH ARE EXPECTED.
REGARDING TEMPERATURES: LOWS TONIGHT MAINLY IN THE TEENS NORTH AND
EAST OF THE MISSOURI RIVER AND IN THE 20S SOUTH AND WEST OF THE
RIVER. STRONG WARM ADVECTION ON FRIDAY SHOULD ALLOW THE SNOW FREE
AREAS OF THE SOUTHWEST TO WARM INTO THE MID 50S TO LOWER 60S (NOTING
THAT HETTINGER HAD REACHED THE LOWER 50S AS OF 2 PM CDT THURSDAY).
ACROSS THE SNOWPACK LOOK FOR HIGHS FRIDAY IN THE 30S.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 314 PM CDT THU MAR 28 2013
H5 PATTERN PER GFS/ECMWF/GEM ADVERTISE AN UPPER LOW FORECAST TO MOVE
FROM THE NORTHWEST TERRITORIES OF CANADA FRIDAY NIGHT INTO THE
NORTHERN GREAT LAKES BY EARLY NEXT WEEK. IN DOING SO...A
NORTHWESTERLY FLOW ALOFT WILL BECOME FIRMLY ENTRENCHED INTO NORTH
DAKOTA FOR THE WEEKEND AND INTO THE EARLY/MIDDLE PART OF NEXT WEEK.
A COUPLE OF SHORTWAVES WILL MOVE THROUGH WITH THEIR ASSOCIATED
SURFACE FEATURES/COLD FRONTAL PASSAGES...RESULTING IN COLDER AIR FOR
THE WEEKEND. THE FIRST COLD FRONT IS FORECAST TO MOVE THROUGH FRIDAY
NIGHT WITH A CHANCE OF A WINTRY MIX OF FREEZING RAIN/SLEET/OR RAIN.
SATURDAY LOOKS DRY...A BIT COOLER BEHIND THE INITIAL COLD FRONT AS
MENTIONED ABOVE. HOWEVER...THE MAIN SURGE OF THE COLDEST AIR WILL
MOVE THROUGH SATURDAY NIGHT...AND REMAIN IN WESTERN AND CENTRAL
NORTH DAKOTA THROUGH MONDAY MORNING. THIS IS WHEN THE MAIN H85
BAROCLINIC ZONE WITH TEMPERATURES AS COLD AS -16C DOMINATE MOST OF
NORTH DAKOTA. WITH THAT BAROCLINIC ZONE PUSHING INTO THE
SOUTHWEST...THE INTERACTION OF LOW LEVEL CONVERGENCE AND A 100KT
H3 JET STREAK WILL PRODUCE ENOUGH LARGE SCALE ASCENT/H85-H3 OMEGA FOR
AN AREA OF SNOW TO DEVELOP LATE SATURDAY NIGHT INTO SUNDAY IN THE SOUTHWEST.
UPWARDS OF AROUND ONE INCH IS FORECAST BY SUNDAY EVENING IN THE
SOUTHWEST. UPPER LEVEL RIDGING AND ITS ASSOCIATED SURFACE HIGH
PRESSURE OF 1037MB WILL FOLLOW FOR MONDAY AND TUESDAY RESULTING IN
DRY WEATHER. THE SURFACE HIGH IS FORECAST TO REACH NORTHWEST NORTH
DAKOTA MONDAY MORNING PRODUCING THE COLDEST READINGS THERE...THEN
SHIFTING INTO THE JAMES RIVER VALLEY BY TUESDAY MORNING. ON THE
BACK SIDE OF THE HIGH PRESSURE...EXPECT A BRIEF RETURN OF MILDER
AIR AS A LOW LEVEL SOUTHERLY FLOW INITIATES TUESDAY INTO TUESDAY NIGHT.
ANOTHER COLD FRONT WHIPS THROUGH WEDNESDAY...HOWEVER PRECIPITATION
LOOKS MINIMAL AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED
AT 845 PM CDT THU MAR 28 2013
LIFR/VLIFR CONDITIONS IN DENSE FOG WILL CONTINUE AT KMOT AND KJMS
POSSIBLY THROUGH 17-18 UTC FRIDAY. SIMILIAR CONDITIONS AT KBIS MAY
IMPROVE SLIGHTLY FASTER IN THE 15-16 UTC TIME FRAME. AS OF 0530
UTC...KISN WAS ON THE FRINGE OF THE DENSE FOG BANK...AND MAY FALL
INTO IFR CONDITIONS BY 08 UTC...AFTER WHICH MID LEVEL CLOUDS
SPREAD ACROSS THE AREA AND MAY LIMIT FOG THEREAFTER FOR KISN. WITH
WEAK UPSLOPE FLOW THROUGH THE NIGHT...KDIK MAY SEE A CONTINUED
TREND TOWARDS MVFR/IFR VISIBILITIES IN FOG. FOR FRIDAY...SCATTERED
PRECIPITATION POSSIBLY IN THE FORM OF FREEZING RAIN OR SLEET MAY
IMPACT KISN AND KMOT...AND POSSIBLY KJMS FRIDAY EVENING. SCATTERED
SHOWERS WITH POSSIBLY AN ISOLATED THUNDERSTORM IS POSSIBLE NEAR
KDIK FRIDAY AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CDT /9 AM MDT/ THIS MORNING FOR
NDZ001>005-009>013-019>023-025-034>037-042-045>048-050-051.
&&
$$
UPDATE...AYD
SHORT TERM...JV
LONG TERM...KS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1016 PM EDT SAT MAR 30 2013
.SYNOPSIS...
HIGH PRESSURE WILL MOVE EAST OF THE REGION TONIGHT. A TROUGH OF
LOW PRESSURE WILL MOVE THROUGH THE OHIO VALLEY ON
SUNDAY...PROVIDING A CHANCE OF RAIN. A COLD FRONT WILL THEN MOVE
THROUGH SUNDAY NIGHT...PROVIDING COOLER TEMPERATURES FOR THE FIRST
PART OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
PCPN IS BEGINNING TO FORM IN SOUTH CENTRAL KY IN RESPONSE TO THE
H5 S/W THAT IS WORKING UP THE OHIO VALLEY. 18Z LOW DEVELOPED A
MORE DEFINED SFC LOW AND MOVED IT ACROSS THE FA OVERNIGHT. THE 00Z
NAM IS A LITTLE LESS DEVELOPED PUT STILL PUSHES THE BEST PCPN
ACROSS THE SE QUARTER OF THE FA BETWEEN 06Z-12Z. THE PREVIOUS
FORECAST HAD THIS SCENARIO...SO ONLY ADJUSTED THE TIMING A LITTLE
AT THE BEGINNING.
TEMPERATURES IN THE E COOLED OFF QUICKLY THIS EVENING WITH THE DRY
DEWPOINTS AND MIGHT DROP A FEW MORE DEGREES BEFORE STARTING TO
RISE TOWARDS MORNING. OVERALL KEPT THE LOWS IN THE PREVIOUS
FORECAST RANGES.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
A SHORTWAVE CURRENTLY MOVING THROUGH THE MIDDLE MISSISSIPPI VALLEY
WILL BEGIN TO AFFECT THE WESTERN CWA BY 06Z. THE AMPLITUDE OF THIS
SHORTWAVE IS NOT ESPECIALLY STRONG...AND IT IS SOMEWHAT TOUGH TO
DISCERN WHEN LOOKING ONLY AT 500MB HEIGHT CONTOURS. WITH THE DRY
AIR IN PLACE OVER MUCH OF THE OHIO VALLEY RIGHT NOW...IT IS NOT
ENTIRELY SURPRISING THAT THE TREND HAS BEEN TOWARD SLIGHTLY DRIER
SOLUTIONS FOR SUNDAY MORNING. THE SIGNAL FROM THE HIGH-
RESOLUTION OUTPUT IS CONFLICTING...WITH THE 12Z SPC-WRF INDICATING
ONLY SCATTERED SHOWERS (AND SOME BIG DRY PATCHES)...AND THE MOST
RECENT HRRR RUN SHOWING A SOLID AREA OF PRECIPITATION FOR THE
SOUTHERN HALF OF THE CWA. TIMING WAS ADJUSTED ON THE POPS...WITH A
SLIGHTLY ADJUSTMENT DOWNWARD IN VALUE AS WELL...AND NO HIGHER THAN
LIKELY FOR THE SOUTHERN CWA.
AN ASPECT OF THE SYSTEM THAT IS AGREED UPON FROM ALL SOURCES IS A
SPLIT IN THE PRECIPITATION BETWEEN A SOUTHERN AREA OF
PRECIPITATION (PRIMARILY AFFECTING KENTUCKY AND TENNESSEE) AND
WITH A NORTHERN STREAM SYSTEM MOVING THROUGH MICHIGAN. THE
NORTHERN SYSTEM WILL LAG BEHIND THE SOUTHERN SYSTEM BY SEVERAL
HOURS...BUT THIS WILL LIKELY ACT TO INITIATE MORE SHOWERS OVER THE
EASTERN CWA THROUGH MID-AFTERNOON. SPC SREF PARAMETERS INDICATE
THAT SOME WEAK INSTABILITY COULD BUILD IN TO THE SOUTHEASTERN AND
EASTERN CWA DURING THIS TIME FRAME...SO THUNDER WAS KEPT IN THE
FORECAST.
BY SUNDAY NIGHT...A COLD FRONT WILL BE MOVING INTO THE NORTHERN
PORTIONS OF THE CWA. WHILE THE COLD ADVECTION IS NOTABLE BEHIND
THE FRONT...THE SURFACE PRESSURE PATTERN IS WEAK...AND FORCING
IS ALMOST NON-EXISTENT. AS A RESULT OF THIS...THE FRONT SHOULD
PASS THROUGH DRY. HOWEVER...IN A REGION OF COLD ADVECTION BEHIND
THE FRONT...A WEAK RIPPLE IN THE FLOW (ROUNDING THE SOUTHWESTERN
EDGE OF THE LARGE UPPER TROUGH) WILL PASS INTO THE CWA. THIS
FEATURE MAY BRING A BAND OF LIGHT PRECIPITATION DURING THE FIRST
TWO-THIRDS OF MONDAY. HOWEVER...THIS HAS BEEN MODELED DRIER ON THE
LAST SET OF RUNS...SO POPS HAVE BEEN LIMITED TO 20 PERCENT.
TEMPERATURES SUPPORT A MIX OF SNOW AND RAIN (WITH GENERALLY SNOW
IN THE NORTH AND GENERALLY RAIN IN THE SOUTH)...BUT AS QPF IS
EXTREMELY LIGHT...THE DAY SHOULD NOT BE A STRIKEOUT.
WITH THE ONLY SIGNIFICANT TEMPERATURE ADVECTION OCCURRING SUNDAY
NIGHT WITH THE COLD FRONT...TEMPS SHOULD REMAIN GENERALLY DIURNAL
THROUGH THE PERIOD. AFTER A DAY OF COLD ADVECTION AND AS SKIES
CLEAR OUT MONDAY NIGHT...TEMPS APPEAR TO BE SET TO DROP INTO THE
20S...10-15 DEGREES BELOW NORMAL FOR EARLY APRIL.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
DEEP MID LVL TROUGH WILL PROGRESS EASTWARD TUESDAY INTO WEDNESDAY
ALLOWING SFC HIGH PRESSURE TO SETTLE INTO THE GREAT LAKES AND
OHIO VALLEY. ON TUESDAY...THERE COULD BE SOME DIURNALLY DRIVEN
CUMULUS BUT IT LOOKS LIKE MOST OF THE REGION WILL BE MOSTLY SUNNY. IT
SHOULD BE MOSTLY CLEAR TUESDAY NIGHT AND MOSTLY SUNNY ON WEDNESDAY.
COLDEST TEMPERATURES ARE EXPECTED TUESDAY INTO TUESDAY NIGHT. HIGHS
ON TUESDAY WILL RANGE FROM THE UPPER 30S NORTH TO THE MID 40S SOUTH.
LOWS TUESDAY NIGHT WILL DROP INTO THE LOWER AND MID 20S. SOME
MODIFICATION IS EXPECTED ON WEDNESDAY BUT TEMPERATURES WILL REMAIN
BELOW NORMAL FOR EARLY APRIL. HIGHS WILL RANGE FROM THE LOWER 40S NE
TO THE UPPER 40S SOUTHWEST.
UPR LVL FLOW WILL TRANSITION TO A MORE ZONAL PATTERN LATE IN THE
WEEK. THERE WILL BE A SPLIT FLOW BETWEEN NRN STREAM ENERGY AND SRN
STREAM ENERGY. MODELS HAVE BEEN OSCILLATING ON HOW THE NRN STREAM
ENERGY WILL INTERACT WITH THE SRN STREAM ENERGY. FOR NOW...HAVE KEPT
AN UPR LVL LOW AND PCPN WITH THE SRN STREAM ENERGY TO OUR SOUTH AND
EAST THURSDAY INTO FRIDAY WHILE A WEAK COLD FRONT DROPS SOUTHEAST
THROUGH THE REGION THURSDAY NIGHT INTO FRIDAY. TEMPERATURES WILL
CONTINUE TO MODERATE WITH HIGHS IN THE 50S ON THURSDAY AND 50S TO
NEAR 60 ON FRIDAY.
FOR FRIDAY NIGHT INTO SATURDAY...SURFACE HIGH PRESSURE WILL PUSH
INTO THE REGION AND WILL EVENTUALLY MOVE EAST. DRY WEATHER WITH
TEMPERATURES NEAR SEASONAL NORMALS ARE EXPECTED.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
H5 S/W SWINGS UP THE OH VALLEY THIS EVENING AND INTO THE TAFS AFT
06Z. BEST LIFT WILL BE ACROSS KY WITH THIS INITIAL SHOT AS A WEAK
SFC LOW DEVELOPS IN KY...THUS AFFECTING CVG/LUK WITH THE BEST
CHANCE OF PCPN AND MVFR CONDITIONS. AS LOW WORKS E BETWEEN 06Z-12Z
SHRA DEVELOP ACROSS SRN OH...LEAVING ILN/CMH/LCK ON THE FRINGE OF
THE PCPN SHIELD. NOT SEEING MUCH IN THE WAY OF INSTABILITY EITHER
SURFACE OR ALOFT WITH THIS INITIAL SHOT SO REMOVED MENTION OF THUNDER.
AS INITIAL SFC TROF SWINGS THRU AROUND 12Z SOME ADDITIONAL SHOWERS
COULD DEVELOP...SO KEPT A MENTION OF VCSH DURING THE MORNING
HOURS. SECONDARY TROF THIN WORK THROUGH AROUND 18Z SCATTERING
THINGS OUT AND PUSHING THE SHRA E. WINDS PICK UP AS THEY TURN TO
THE W BEHIND THIS TROF. SOME CAPE DEVELOPS INT HE AFTN...BUT WILL
PCPN SHOULD BE SHUNTED E BEFORE THIS CAN BE REALIZED AS THUNDER.
OUTLOOK...MVFR POSSIBLE ON MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...SITES
SHORT TERM...HATZOS
LONG TERM...HICKMAN
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
811 PM EDT SAT MAR 30 2013
.SYNOPSIS...
HIGH PRESSURE WILL MOVE EAST OF THE REGION TONIGHT. A TROUGH OF
LOW PRESSURE WILL MOVE THROUGH THE OHIO VALLEY ON
SUNDAY...PROVIDING A CHANCE OF RAIN. A COLD FRONT WILL THEN MOVE
THROUGH SUNDAY NIGHT...PROVIDING COOLER TEMPERATURES FOR THE FIRST
PART OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A RELATIVELY DRY SURFACE AIR MASS HAS INHIBITED CUMULUS
DEVELOPMENT TODAY. A LOOK AT SURFACE OBS SHOWS THAT DEWPOINTS OVER
THE REGION REMAIN IN THE 20S TO LOWER 30S...WITH DEWPOINTS OVER 40
SOUTH AND WEST OF A BOUNDARY THAT CUTS THROUGH THE FAR
SOUTHWESTERN TIP OF INDIANA. AT THE SAME TIME...HIGH CLOUDS HAVE
BEEN INCREASING...AND MOISTURE IS EXPECTED TO CONTINUE TO LOWER
THROUGH THE NEAR TERM OF THE FORECAST.
THE FOCUS FOR PRECIPITATION WILL BE ON A SHORTWAVE CURRENTLY
MOVING ACROSS MISSOURI AND INTO ILLINOIS. THERE WILL BE EFFECTS ON
THE CWA BEFORE MORNING...BUT FOR THE SAKE OF EASE...THIS FEATURE
WILL BE DISCUSSED IN THE SHORT TERM SECTION OF THE AFD.
WITH CLOUDS MOVING IN...AND WARM ADVECTION AHEAD OF THE
SHORTWAVE...OVERNIGHT TEMPS WILL BE AT LEAST TEN DEGREES WARMER
THAN LAST NIGHT. MIN TEMP VALUES ARE NEAR OR SLIGHTLY WARMER THAN
THE MODEL BLEND...WHICH EXHIBITS A RELATIVELY SMALL
SPREAD. HOWEVER...THE FORECAST IS NOT AS WARM AS THE RAP13.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
A SHORTWAVE CURRENTLY MOVING THROUGH THE MIDDLE MISSISSIPPI VALLEY
WILL BEGIN TO AFFECT THE WESTERN CWA BY 06Z. THE AMPLITUDE OF THIS
SHORTWAVE IS NOT ESPECIALLY STRONG...AND IT IS SOMEWHAT TOUGH TO
DISCERN WHEN LOOKING ONLY AT 500MB HEIGHT CONTOURS. WITH THE DRY
AIR IN PLACE OVER MUCH OF THE OHIO VALLEY RIGHT NOW...IT IS NOT
ENTIRELY SURPRISING THAT THE TREND HAS BEEN TOWARD SLIGHTLY DRIER
SOLUTIONS FOR SUNDAY MORNING. THE SIGNAL FROM THE HIGH-
RESOLUTION OUTPUT IS CONFLICTING...WITH THE 12Z SPC-WRF INDICATING
ONLY SCATTERED SHOWERS (AND SOME BIG DRY PATCHES)...AND THE MOST
RECENT HRRR RUN SHOWING A SOLID AREA OF PRECIPITATION FOR THE
SOUTHERN HALF OF THE CWA. TIMING WAS ADJUSTED ON THE POPS...WITH A
SLIGHTLY ADJUSTMENT DOWNWARD IN VALUE AS WELL...AND NO HIGHER THAN
LIKELY FOR THE SOUTHERN CWA.
AN ASPECT OF THE SYSTEM THAT IS AGREED UPON FROM ALL SOURCES IS A
SPLIT IN THE PRECIPITATION BETWEEN A SOUTHERN AREA OF
PRECIPITATION (PRIMARILY AFFECTING KENTUCKY AND TENNESSEE) AND
WITH A NORTHERN STREAM SYSTEM MOVING THROUGH MICHIGAN. THE
NORTHERN SYSTEM WILL LAG BEHIND THE SOUTHERN SYSTEM BY SEVERAL
HOURS...BUT THIS WILL LIKELY ACT TO INITIATE MORE SHOWERS OVER THE
EASTERN CWA THROUGH MID-AFTERNOON. SPC SREF PARAMETERS INDICATE
THAT SOME WEAK INSTABILITY COULD BUILD IN TO THE SOUTHEASTERN AND
EASTERN CWA DURING THIS TIME FRAME...SO THUNDER WAS KEPT IN THE
FORECAST.
BY SUNDAY NIGHT...A COLD FRONT WILL BE MOVING INTO THE NORTHERN
PORTIONS OF THE CWA. WHILE THE COLD ADVECTION IS NOTABLE BEHIND
THE FRONT...THE SURFACE PRESSURE PATTERN IS WEAK...AND FORCING
IS ALMOST NON-EXISTENT. AS A RESULT OF THIS...THE FRONT SHOULD
PASS THROUGH DRY. HOWEVER...IN A REGION OF COLD ADVECTION BEHIND
THE FRONT...A WEAK RIPPLE IN THE FLOW (ROUNDING THE SOUTHWESTERN
EDGE OF THE LARGE UPPER TROUGH) WILL PASS INTO THE CWA. THIS
FEATURE MAY BRING A BAND OF LIGHT PRECIPITATION DURING THE FIRST
TWO-THIRDS OF MONDAY. HOWEVER...THIS HAS BEEN MODELED DRIER ON THE
LAST SET OF RUNS...SO POPS HAVE BEEN LIMITED TO 20 PERCENT.
TEMPERATURES SUPPORT A MIX OF SNOW AND RAIN (WITH GENERALLY SNOW
IN THE NORTH AND GENERALLY RAIN IN THE SOUTH)...BUT AS QPF IS
EXTREMELY LIGHT...THE DAY SHOULD NOT BE A STRIKEOUT.
WITH THE ONLY SIGNIFICANT TEMPERATURE ADVECTION OCCURRING SUNDAY
NIGHT WITH THE COLD FRONT...TEMPS SHOULD REMAIN GENERALLY DIURNAL
THROUGH THE PERIOD. AFTER A DAY OF COLD ADVECTION AND AS SKIES
CLEAR OUT MONDAY NIGHT...TEMPS APPEAR TO BE SET TO DROP INTO THE
20S...10-15 DEGREES BELOW NORMAL FOR EARLY APRIL.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
DEEP MID LVL TROUGH WILL PROGRESS EASTWARD TUESDAY INTO WEDNESDAY
ALLOWING SFC HIGH PRESSURE TO SETTLE INTO THE GREAT LAKES AND
OHIO VALLEY. ON TUESDAY...THERE COULD BE SOME DIURNALLY DRIVEN
CUMULUS BUT IT LOOKS LIKE MOST OF THE REGION WILL BE MOSTLY SUNNY. IT
SHOULD BE MOSTLY CLEAR TUESDAY NIGHT AND MOSTLY SUNNY ON WEDNESDAY.
COLDEST TEMPERATURES ARE EXPECTED TUESDAY INTO TUESDAY NIGHT. HIGHS
ON TUESDAY WILL RANGE FROM THE UPPER 30S NORTH TO THE MID 40S SOUTH.
LOWS TUESDAY NIGHT WILL DROP INTO THE LOWER AND MID 20S. SOME
MODIFICATION IS EXPECTED ON WEDNESDAY BUT TEMPERATURES WILL REMAIN
BELOW NORMAL FOR EARLY APRIL. HIGHS WILL RANGE FROM THE LOWER 40S NE
TO THE UPPER 40S SOUTHWEST.
UPR LVL FLOW WILL TRANSITION TO A MORE ZONAL PATTERN LATE IN THE
WEEK. THERE WILL BE A SPLIT FLOW BETWEEN NRN STREAM ENERGY AND SRN
STREAM ENERGY. MODELS HAVE BEEN OSCILLATING ON HOW THE NRN STREAM
ENERGY WILL INTERACT WITH THE SRN STREAM ENERGY. FOR NOW...HAVE KEPT
AN UPR LVL LOW AND PCPN WITH THE SRN STREAM ENERGY TO OUR SOUTH AND
EAST THURSDAY INTO FRIDAY WHILE A WEAK COLD FRONT DROPS SOUTHEAST
THROUGH THE REGION THURSDAY NIGHT INTO FRIDAY. TEMPERATURES WILL
CONTINUE TO MODERATE WITH HIGHS IN THE 50S ON THURSDAY AND 50S TO
NEAR 60 ON FRIDAY.
FOR FRIDAY NIGHT INTO SATURDAY...SURFACE HIGH PRESSURE WILL PUSH
INTO THE REGION AND WILL EVENTUALLY MOVE EAST. DRY WEATHER WITH
TEMPERATURES NEAR SEASONAL NORMALS ARE EXPECTED.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
H5 S/W SWINGS UP THE OH VALLEY THIS EVENING AND INTO THE TAFS AFT
06Z. BEST LIFT WILL BE ACROSS KY WITH THIS INITIAL SHOT AS A WEAK
SFC LOW DEVELOPS IN KY...THUS AFFECTING CVG/LUK WITH THE BEST
CHANCE OF PCPN AND MVFR CONDITIONS. AS LOW WORKS E BETWEEN 06Z-12Z
SHRA DEVELOP ACROSS SRN OH...LEAVING ILN/CMH/LCK ON THE FRINGE OF
THE PCPN SHIELD. NOT SEEING MUCH IN THE WAY OF INSTABILITY EITHER
SURFACE OR ALOFT WITH THIS INITIAL SHOT SO REMOVED MENTION OF THUNDER.
AS INITIAL SFC TROF SWINGS THRU AROUND 12Z SOME ADDITIONAL SHOWERS
COULD DEVELOP...SO KEPT A MENTION OF VCSH DURING THE MORNING
HOURS. SECONDARY TROF THIN WORK THROUGH AROUND 18Z SCATTERING
THINGS OUT AND PUSHING THE SHRA E. WINDS PICK UP AS THEY TURN TO
THE W BEHIND THIS TROF. SOME CAPE DEVELOPS INT HE AFTN...BUT WILL
PCPN SHOULD BE SHUNTED E BEFORE THIS CAN BE REALIZED AS THUNDER.
OUTLOOK...MVFR POSSIBLE ON MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...HICKMAN
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS TULSA OK
1150 PM CDT THU MAR 28 2013
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VFR CONDITIONS ARE THE NORM ACROSS THE AREA AT THIS TIME..THAT
IS EXPECTED TO CHANGE SOME AS WE MOVE INTO FRIDAY MORNING
WITH MVFR CONDITIONS DEVELOPING DUE TO CEILINGS AND SCATTERED
SHOWERS AND THUNDERSTORMS. CONDITIONS WILL IMPROVE SOME LATE
FRIDAY MORNING/EARLY AFTERNOON BEFORE MORE SHOWERS AND THUNDERSTORMS
MOVE INTO THE AREA.
&&
.PREV DISCUSSION... /ISSUED 910 PM CDT THU MAR 28 2013/
UPDATE...
FORECAST WAS UPDATED TO REDUCE POPS THIS EVENING BASED ON LATEST
DATA. SEE DISCUSSION BELOW.
DISCUSSION...
THE LATEST DATA FROM THE HRRR AND NEW 00Z NAM SUGGEST THAT THE
ACTIVITY WILL BE SLOWER TO GET GOING TONIGHT...AND THUS POPS WERE
REDUCED THRU 06Z. POPS AFT 06Z LOOK GOOD...AND ARE A GOOD
COMPROMISE BETWEEN THE HRRR AND NAM SOLUTIONS. ISENTROPIC CHARTS
EXPLAIN WHY THE ACTIVITY WILL BE SLOWER TO GET GOING...WITH LITTLE
IN THE WAY OF ASCENT FORECAST THRU 06Z. BY 06Z AND AFTER...THE
295K SHOWS SOME LIFT AND GOOD MOISTURE TRANSPORT AIMED AT THE
OZARK REGION. THERE IS STILL A LIMITED RISK OF AN ISOLATED SEVERE
HAIL STORM WITH POTENTIAL FOR UP TO HALF DOLLAR SIZE GIVEN
SUFFICIENT SHEAR AND INCREASING ELEVATED INSTABILITY ACROSS
EASTERN OKLAHOMA AFT MIDNIGHT.
LACY
PREV DISCUSSION... /ISSUED 630 PM CDT THU MAR 28 2013/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
CONDITIONS WILL DETERIORATE TONIGHT WITH MVFR CONDITIONS
DEVELOPING AFTER MIDNIGHT AND CONTINUING THROUGH FRIDAY
MORNING. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED
TO AFFECT AREA TAFS LATE TONIGHT INTO FRIDAY MORNING WITH
SOME REDEVELOPED EXPECTED LATE FRIDAY AFTERNOON PRIOR TO
THE EXPIRATION OF THE CURRENT TAF PERIOD.
PREV DISCUSSION... /ISSUED 346 PM CDT THU MAR 28 2013/
DISCUSSION...
A NEARLY STATIONARY FRONTAL BOUNDARY WAS POSITIONED FROM THE
OKLAHOMA PANHANDLE TO SOUTHEAST KANSAS THIS AFTERNOON. SOUTH OF
THE BOUNDARY...TEMPERATURES ARE RUNNING ABOUT 5 TO 10 DEGREES
WARMER THAN THIS TIME YESTERDAY WITH HIGH CLOUDS AND SOUTHERLY
WINDS BEING COMMON. LOW LEVEL MOISTURE HAS ALSO INCREASED FROM
SOUTH TO NORTH ACROSS THE REGION THIS AFTERNOON...LIMITING FIRE
WEATHER DANGERS FOR EASTERN OKLAHOMA AND NORTHWEST ARKANSAS.
THE FRONTAL BOUNDARY JUST NORTH OF THE CWA WILL BE THE FOCUS FOR
CHANCES OF SHOWERS AND THUNDERSTORMS OVER THE NEXT SEVERAL DAYS AS
MID LEVEL WAVES PROGRESS THROUGH THE PLAINS WITHIN NORTHWESTERLY
UPPER LEVEL FLOW. THE FIRST WAVE IS EXPECTED TO MOVE THROUGH
TONIGHT AND FRIDAY...WITH A SECOND WAVE FRIDAY NIGHT AND SATURDAY.
CHANCES FOR SHOWERS AND THUNDERSTORMS BECOME POSSIBLE THIS EVENING
ACROSS THE REGION WITH GREATER CHANCES LATE TONIGHT AND FRIDAY
ACROSS NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS. CHANCES THEN
CONTINUE TO SPREAD SOUTHWARD FRIDAY EVENING AND SATURDAY WITH THE
NEXT WAVE. WARM SURFACE TEMPS...STEEP LAPSE RATES AND COLD
TEMPERATURES ALOFT DURING THIS TIME FRAME WILL ALLOW FOR
INSTABILITY TO DEVELOP OVER THE REGION WHICH COULD ALLOW FOR SOME
THUNDERSTORMS TO BECOME STRONG TO SEVERE WITH LARGE HAIL BEING THE
MAIN THREAT.
THE FRONTAL BOUNDARY IS PROGGED TO PUSH INTO EASTERN OKLAHOMA AND
NORTHWEST ARKANSAS SATURDAY NIGHT AS A MORE DEFINED UPPER LEVEL
WAVE DROPS SOUTHEAST OUT OF CANADA. THIS WILL CONTINUE CHANCES FOR
SHOWERS AND THUNDERSTORMS INTO SUNDAY. LATEST MODEL SOLUTIONS ARE
INDICATING THAT THE FRONTAL BOUNDARY COULD HANG UP NEAR THE RED
RIVER VALLEY...WHICH WOULD CONTINUE PRECIP CHANCES ACROSS THE
SOUTH DURING THE DAY SUNDAY. TEMPERATURES DURING THE DAY SUNDAY
LOOK TO REMAIN WARM WITH HIGHS IN THE MID 60S TO LOW 70S POSSIBLE.
THE WARM TEMPERATURES WILL BE QUICK TO MOVE OUT SUNDAY NIGHT AND
MONDAY AS ANOTHER MORE STRONGER COLD FRONT PUSHES THROUGH THE
REGION. CHANCES OF SHOWERS AND THUNDERSTORMS WILL AGAIN SPREAD
OVER THE REGION DURING THE DAY MONDAY WITH THE MOVEMENT OF THE
FRONT. BEHIND THE FRONT...MUCH COLDER AND DRIER AIR IS EXPECTED
TO FILTER IN WITH TEMPERATURES DROPPING DURING THE DAY BEHIND THE
FRONT. LOWS TUESDAY MORNING COULD POTENTIALLY REACH CLOSE TO
FREEZING NEAR THE KANSAS BORDER. THIS FRONT LOOKS TO PUSH THROUGH
THE REGION AND KEEP AN UPPER LEVEL WAVE MOVING OUT OF THE DESERT
SOUTHWEST SOUTH OF THE REGION. THIS SHOULD KEEP PRECIP SOUTH OF
THE REGION FOR THE MIDDLE PART OF THE WEEK.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...10
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1029 PM CDT SAT MAR 30 2013
.UPDATE...
IT IS QUIET ACROSS THE REGION AT THIS TIME BUT ANOTHER COMPLEX OF
STORMS IS EXPECTED TO CROSS OUT OF OKLAHOMA AND INTO NORTH TEXAS
NEAR DAYBREAK SUNDAY MORNING. BOTH THE LATEST NAM AND OCCASIONAL
RUNS OF THE RAP DEVELOP STORMS AROUND AND/OR NORTHEAST OF THE DFW
METROPLEX AROUND 4 AM. THE LATEST RUN OF THE RAP DOES NOT HAVE
THESE STORMS. AROUND 4 AM...THE MODELS STILL HAVE THE BEST LIFT
WEST OF THE REGION BUT SOME WEAK HEIGHT FALLS MAY BE STARTING TO
SPREAD EAST AS A SHORTWAVE APPROACHES THE REGION FROM THE WEST.
ISENTROPIC LIFT LOOKS TO BE FAIRLY WEAK AT THIS TIME WITH SOME
WEAK LIFT ON THE 295K SURFACE. BUFR SOUNDINGS AT THIS TIME SHOW A
WELL CAPPED ENVIRONMENT WITH NOT MUCH MOISTURE OR INSTABILITY
ABOVE THE CAP. THEREFORE...THINK IT WILL BE DIFFICULT FOR STORMS
TO DEVELOP THIS EARLY BUT NOT ENTIRELY IMPOSSIBLE.
INSTEAD...THE MAIN FOCUS FOR THE OVERNIGHT PERIOD SHIFTS TO THE
COMPLEX OF STORMS OR MCS THAT WILL DEVELOP ALONG THE COLD FRONT IN
OKLAHOMA AND MARCH SOUTHEAST INTO NORTH TEXAS. THE BEST TIMING
FOR THESE STORMS TO CROSS THE RED RIVER NEAR MONTAGUE AND COOKE
COUNTIES IS AROUND 5-6 AM. THEREFORE...TRENDED HIGHEST POPS BACK
TO THE WEST SOME AND ALSO TRIMMED ACROSS THE SOUTH SOME DUE TO THE
SLIGHTLY SLOWER ARRIVAL TIME. BECAUSE OF THIS SLOWER TIME...ALSO
ADJUSTED THE HIGHER POPS SUNDAY MORNING FARTHER NORTH AND WEST. AT
THE TIME THE STORMS ARRIVE...THE CAP WILL BE WEAK OR ERODED AND
THERE WILL BE A THREAT FOR SEVERE STORMS PRODUCING HAIL AND
DAMAGING WINDS. SOME ADDITIONAL DECENT RAINFALL IS ALSO LIKELY
WITH THIS STORM SYSTEM...ESPECIALLY OVER THE NORTHERN AND EASTERN
COUNTIES.
ADDITIONAL STORMS WILL ALSO BE POSSIBLE SUNDAY AFTERNOON ACROSS
THE SOUTHERN COUNTIES WHERE THE FRONT WILL BE LOCATED IN THE
AFTERNOON HOURS. THESE STORMS COULD POTENTIALLY BE SEVERE AS WELL.
82/JLD
&&
.AVIATION...
A RELATIVELY QUIET EVENING FOR ALL NORTH TEXAS TERMINALS.
CHALLENGES INCLUDE TIMING OF MVFR CIGS AFTER MIDNIGHT AND STORMS
BY DAYBREAK SUNDAY AND AFTER WITH THE ARRIVAL OF A COLD FRONT.
ISOLATED STRONG TO SEVERE STORMS ARE DEVELOPING TO THE WEST ON
THE DRYLINE AND NORTHWEST OFF A WEAK SURFACE BOUNDARY ACROSS
SOUTHWEST OKLAHOMA. MEAN STEERING CURRENTS WILL MOVE THIS ACTIVITY
SOUTHEAST WITH TIME...HOWEVER WE EXPECT A DIMINISHING TREND AFTER
NIGHTFALL AS WE AWAIT THE BETTER FORCING WITH A SHORTWAVE AND COLD
FRONT LATE TONIGHT AND SUNDAY MORNING. VFR WILL PREVAIL THROUGH
THE EVENING HOURS WITH SOUTHEAST WINDS AROUND 10 KTS.
THE COLD FRONT OVER NORTHERN OKLAHOMA BEGINS MOVING SOUTH AFTER
MIDNIGHT WITH THE SUPPORT FROM A SHORTWAVE MOVING OUT OF THE
SOUTHERN ROCKIES. MVFR CIGS WILL DEVELOP JUST AHEAD OF THE COLD
FRONT AS WINDS WEAKEN AND THE BOUNDARY LAYER COOLS. CHANCES FOR
SHOWERS AND STORMS WILL INCREASE AT METRO AIRPORTS AROUND SUNRISE
AND LAST THROUGH MID MORNING...WHILE ARRIVING MORE TOWARD MIDDAY
OR AFTER AT WACO AS THE COLD FRONT MOVES INTO THE AREA. WINDS MAY
VEER BRIEFLY SOUTHWEST AROUND 10 KTS JUST AHEAD OF THE COLD FRONT...
BUT SHIFT TO THE NORTH AT 10 TO 15 KTS BEHIND IT BY LATE MORNING
AT DFW AND IN THE EARLY AFTERNOON AT WACO.
CIGS WILL SLOWLY RISE DURING THE AFTERNOON BACK INTO THE VFR
CATEGORY. BY EVENING...WINDS VEER NORTHEAST AT 5-10 KTS...AS
SURFACE HIGH PRESSURE SETTLES IN FROM THE NORTH.
05/
&&
.PREV UPDATE...
.UPDATE...
HAVE CANCELLED THE SEVERE THUNDERSTORM WATCH FOR THE NORTHERN
PORTIONS OF THE AREA. STORMS IN THE SOUTHWESTERN COUNTIES CONTINUE
TO WEAKEN WITH THE LOST OF HEATING AND WILL NOW SHIFT TO ASSESS
THE RAIN AND SEVERE WEATHER THREAT OVERNIGHT.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 351 PM CDT SAT MAR 30 2013/
SOMEWHAT OF A COMPLEX SURFACE PATTERN IN PLACE ACROSS THE SOUTHERN
PLAINS THIS AFTERNOON WHICH WILL AFFECT WHICH AREAS SEE
THUNDERSTORMS OVER THE NEXT 12 HOURS. A BROAD SURFACE LOW PERSISTS
ACROSS FAR WEST TEXAS NEAR LUBBOCK WITH WHAT HAS BEEN A QUASI
STATIONARY FRONTAL BOUNDARY EXTENDING TO THE NORTHEAST INTO
SOUTHERN KANSAS. THIS ELONGATED TROUGH WILL BECOME A WELL DEFINED
COLD FRONT BY LATE TONIGHT AND BEGIN TO MOVE SOUTH INTO THE RED
RIVER VALLEY. MEANWHILE A WELL DEFINED WARM SECTOR EXISTS FROM
NEAR SAN ANGELO NORTHWARD TO NEAR OKLAHOMA CITY AND BACK SOUTHEAST
INTO THE ARKLATEX. THERE IS ALSO ONE DISTINCT OUTFLOW BOUNDARY
WHICH IS NOW ALSO MOVING INTO THE ARKLATEX WITH SCATTERED
THUNDERSTORMS DEVELOPING ALONG IT. 20Z OBJECTIVE ANALYSIS
INDICATES A MODERATELY UNSTABLE AIRMASS IN PLACE ACROSS NORTH
TEXAS WITH SURFACE BASED CAPE AROUND 1500J/KG AND LITTLE
CONVECTIVE INHIBITION REMAINING ESPECIALLY ACROSS THE EASTERN HALF
OF THE CWA. TWO AMDAR VAPOR SOUNDINGS HOWEVER JUST CAME IN ABOUT
20 MINUTES AGO FROM DFW AIRPORT AND REVEALED THAT SUFFICIENT CONVECTIVE
INHIBITION REMAINS IN PLACE. THE FLIGHT PATHS CAME IN FROM THE
EAST WHERE THE CAP WAS OBSERVED SO THIS YIELDS HIGHER CONFIDENCE
THAT CAPPING REMAINS IN PLACE FARTHER EAST THAN INDICATED BY
OBJECTIVE ANALYSIS. A VEERED LOW LEVEL WIND PROFILE IS ALSO
REINFORCING A WARM LAYER ALOFT ESPECIALLY ACROSS THE WESTERN
COUNTIES THIS AFTERNOON.
SO WHAT HAPPENS... WITH THE LACK OF ANY APPRECIABLE LARGE SCALE
FORCING FOR ASCENT IN THE NEXT 6 HOURS IT APPEARS UNLIKELY THAT
THUNDERSTORMS WILL DEVELOP ACROSS NORTH TEXAS THROUGH THIS
EVENING. MESOSCALE FORCING ALONG THE OUTFLOW BOUNDARY TO THE EAST
IS MORE THAN SUFFICIENT FOR THUNDERSTORM DEVELOPMENT TO CONTINUE
IN THE ARKLATEX...AND WILL HAVE SOME 20 POPS ACROSS THE FAR
NORTHEAST TO ACCOUNT FOR THIS. OTHERWISE...IT APPEARS THAT WE WILL
HAVE TO WAIT UNTIL LATER TONIGHT FOR ADDITIONAL THUNDERSTORMS TO
AFFECT THE AREA. THE ONE CAVEAT TO THIS IS THE FAR WESTERN
COUNTIES. THE HIGH RES GUIDANCE AND TO A LESSER EXTENT THE GFS/NAM
ALL APPEAR TO ATTEMPT TO CONVECT BY 00Z THIS EVENING. THIS APPEARS
TO BE IN RESPONSE TO SURFACE HEATING WITH FORCING ALONG THE
DRYLINE. CONFIDENCE IN THIS SCENARIO IS LOW NOW GIVEN THE VEERED
LOW LEVEL WIND FIELDS AND A LACK OF SUBSTANTIAL CONVERGENCE. AFTER
00Z IT APPEARS THAT THE SURFACE WINDS MAY BACK MORE IN RESPONSE TO
UPSTREAM HEIGHT FALLS. THIS COULD LOCALLY ENHANCE CONVERGENCE
ACROSS THE WESTERN COUNTIES. IF ANYTHING WERE TO DEVELOP IN THIS
AREA IT WOULD LIKELY BE SEVERE.
THE MORE LIKELY SCENARIO FOR THUNDERSTORMS TONIGHT APPEARS TO BE
IN RESPONSE TO INCREASING FORCING FOR ASCENT AS A SHORTWAVE MOVES
THROUGH THE CENTRAL PLAINS AND HEIGHT FALLS OVERSPREAD THE REGION.
THE COLD FRONT ACROSS OKLAHOMA WILL BEGIN TO MOVE SOUTH AND
SCATTERED TO NUMEROUS THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG
IT. ADDITIONAL THUNDERSTORMS MAY DEVELOP AHEAD OF THE FRONT
EARLIER IN THE NIGHT ALONG A PRE-FRONTAL TROUGH WHERE CAPPING GETS
SUFFICIENTLY WEAKENED IN RESPONSE TO INCREASING LIFT. ALL OF THIS
IS LIKELY TO INITIATE ACROSS SOUTHERN OKLAHOMA AND MOVE SOUTH
ACROSS THE RED RIVER. THE BEST TIMING FOR THE INITIAL CONVECTIVE
DEVELOPMENT...IF IT CAN DEVELOP...APPEARS TO BE AROUND MIDNIGHT.
IF CONVECTION FAILS TO INITIATE ALONG THIS PRE-FRONTAL TROUGH THEN
THE MAIN SHOW SHOULD BE ALONG THE FRONT VERY LATE TONIGHT INTO
EARLY SUNDAY MORNING. THE ATMOSPHERE REMAINS MODERATELY UNSTABLE
WITH VERY STEEP LAPSE RATES SO THUNDERSTORMS WILL HAVE THE
POTENTIAL TO BE SEVERE. IF THE EARLIER ROUND OF STORMS CAN
DEVELOP...ITS SEVERE POTENTIAL WILL BE GREATER AS IT WILL HAVE AN
UNTAPPED RESERVOIR OF INSTABILITY TO WORK WITH. IT IS LIKELY THAT
THUNDERSTORMS THAT DEVELOP THAT LATE IN THE NIGHT WILL BE SLIGHTLY
ELEVATED...HOWEVER WITH 1500-2000J/KG OF MUCAPE AND 40-50KTS OF
DEEP LAYER SHEAR TO WORK WITH...ELEVATED SUPERCELLS ARE LIKELY.
LARGE HAIL WILL BE THE MAIN THREAT...ALTHOUGH DAMAGING WINDS CAN
EASILY MAKE IT TO THE GROUND DESPITE BEING SLIGHTLY ELEVATED. WILL
HAVE POPS INCREASING THROUGH THE NIGHT TONIGHT WITH HIGHEST
NUMBERS ALONG THE RED RIVER AND NORTHEAST COUNTIES.
ONE OR MORE CLUSTERS OF THUNDERSTORMS SHOULD BE ONGOING EARLY
EASTER MORNING ACROSS NORTH TEXAS. AS THE FRONT CONTINUES TO MOVE
SOUTH THE THUNDERSTORMS WILL GRADUALLY SHIFT SOUTH AS WELL THROUGH
THE DAY. BY AFTERNOON...THE ATMOSPHERE ACROSS THE SOUTHERN HALF OF
THE CWA WILL BE UNSTABLE AND SEVERE THUNDERSTORMS WILL BE POSSIBLE
ACROSS THE SOUTHERN COUNTIES. THESE WILL HAVE THE POTENTIAL TO
PRODUCE LARGE HAIL AND DAMAGING WINDS.
MONDAY APPEARS TO PROVIDE A BRIEF RESPITE FROM THE ACTIVE WEATHER
WITH THE OLD FRONTAL BOUNDARY TO THE SOUTH AND WEAK RIDGING ALOFT.
THE BREAK IS EXPECTED TO BE SHORT THOUGH AS A STRONG UPPER LOW
MOVES INTO THE 4-CORNERS REGION. THE STRONGER FRONT ASSOCIATED
WITH THIS SYSTEM WILL SLIDE SOUTH WITH STRONG ISENTROPIC ASCENT
COMMENCING MONDAY NIGHT. SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ARE EXPECTED LATE MONDAY NIGHT. BETTER RAIN CHANCES
ACROSS NORTH TEXAS WILL BE TUESDAY AND ESPECIALLY TUESDAY NIGHT AS
THE LOW SLOWLY MOVES EAST. WILL HAVE HIGH POPS ACROSS THE ENTIRE
CWA AS IT APPEARS VERY BENEFICIAL RAINFALL WILL OCCUR ACROSS THE
REGION. THUNDERSTORM ACTIVITY IS EXPECTED TO BE ELEVATED AND MORE
ISOLATED IN NATURE DURING THIS TIME...SO WIDESPREAD SEVERE WEATHER
IS NOT EXPECTED AT THIS TIME. DID WARM TEMPS UP A BIT THROUGH
MIDWEEK AS GUIDANCE IS NOT QUITE AS COLD WITH THE AIR COMING DOWN.
IT WILL STILL BE CHILLY WITH HIGHS IN THE UPPER 50S AND LOWER 60S.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 62 74 53 76 54 / 50 70 10 10 40
WACO, TX 65 76 58 77 59 / 20 60 20 10 40
PARIS, TX 58 72 52 75 47 / 60 80 10 10 20
DENTON, TX 61 74 53 77 50 / 60 70 10 10 50
MCKINNEY, TX 61 73 53 75 52 / 60 80 10 10 40
DALLAS, TX 64 76 55 78 56 / 50 70 20 10 40
TERRELL, TX 63 74 54 76 56 / 50 80 20 10 30
CORSICANA, TX 63 76 58 77 59 / 20 70 20 10 30
TEMPLE, TX 64 78 58 79 61 / 20 60 20 10 30
MINERAL WELLS, TX 60 75 53 79 52 / 40 50 10 10 50
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/82
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1240 PM CDT FRI MAR 29 2013
.AVIATION...
A PERIOD OF UNSETTLED WEATHER IS EXPECTED THE NEXT 24-30 HOURS FOR
ALL NORTH TEXAS TAF SITES. AN UPPER LEVEL DISTURBANCE WILL BE
MOVING ACROSS THE REGION TONIGHT AND WILL PRODUCE SCATTERED TO
CLUSTERS OF CONVECTION THAT BEGIN TO THE WEST AND TRACK EAST
ACROSS THE METROPLEX TONIGHT /04-09 UTC /. HAVE ADDED A TEMPO
GROUP FOR TSRA/BKN018CB 05-08 UTC. THERE IS ALSO THE POTENTIAL
FOR A FEW STORMS TO BE MARGINALLY SEVERE OR SEVERE. IF THIS PANS
OUT...THEN THE SEVERE WEATHER THREAT WILL BE MAINLY LARGE HAIL
/ONE INCH TO TWO INCHES/ AND A LESSER THREAT OF DAMAGING WINDS.
KACT SHOULD ESCAPE THIS EVENT BUT SHOULD SEE VCSH OVERNIGHT.
CIGS ARE LIFTING AND EXPECT VFR SKIES THE REST OF THE AFTERNOON.
MVFR CIGS WILL RETURN TONIGHT AFTER 03 UTC AND LAST THROUGH MID
SUNDAY MORNING BEFORE IMPROVING. ALL SITES HAVE THE POTENTIAL TO
SEE BRIEF IFR CONDITIONS 11-14 UTC SUNDAY AFTER THE CONVECTION
MOVES EAST OF THE TAF SITES...BUT CONFIDENCE IS NOT HIGH ENOUGH TO
INCLUDE IN THIS CYCLE.
WINDS WILL REMAIN SOUTHERLY 13-18KTS TODAY AND SUNDAY...AND
10-15KTS TONIGHT.
75
&&
.UPDATE...
CURRENT FORECAST THROUGH THIS AFTERNOON IS IN GOOD SHAPE AND WILL
ONLY MAKE SOME MINOR ADJUSTMENTS TO THE HOURLY GRIDDED DATA.
SURFACE ANALYSIS INDICATES A WEAK LOW PRESSURE CENTER ACROSS THE
TEXAS PANHANDLE THIS MORNING WITH A STATIONARY FRONTAL BOUNDARY
EXTENDING EASTWARD ACROSS CENTRAL OKLAHOMA. STRONG LOW LEVEL WARM
ADVECTION HAS AIDED IN A CLUSTER OF SHOWERS AND ELEVATED
THUNDERSTORMS ACROSS CENTRAL OKLAHOMA. THESE SHOULD PRIMARILY
CONTINUE TO MOVE EAST/SOUTHEAST THROUGH THE DAY WITH A GENERAL
WEAKENING TREND AS LOW LEVEL FLOW BACKS AND WEAKENS OVER THE NEXT
SEVERAL HOURS. FARTHER SOUTH...SOME SHOWERS ARE APPROACHING THE
NORTHWEST COUNTIES. THIS ACTIVITY SHOULD REMAIN IN THE FORM OF
SHOWERS AS A STRONG CAPPING INVERSION IS PRESENT ACROSS NORTH
TEXAS AT THE PRESENT TIME.
FOCUS QUICKLY TURNS TO AN APPROACHING MID LEVEL DISTURBANCE
CURRENTLY ENTERING NEW MEXICO. THIS FEATURE INITIALLY WAS NOT
SAMPLED WELL BY THE GUIDANCE AS IT WAS OFF THE COAST OF BAJA
CALIFORNIA. IT SHOWED UP BETTER IN THE 12Z UPPER AIR ANALYSIS AS A
MID LEVEL COLD POCKET OVER TUCSON ARIZONA THIS MORNING AND NOW
APPEARS TO BE APPROACHING FAR WEST TEXAS. 12Z GUIDANCE APPEARS TO
GENERATE SIGNIFICANTLY MORE FORCING FOR ASCENT WITH THIS FEATURE
THIS AFTERNOON DURING PEAK HEATING. BY 00Z A DRYLINE SHOULD BE
LOCATED ACROSS THE PANHANDLE AS THE STRONGEST FORCING OVERSPREADS
IT. SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP BY LATE
AFTERNOON/EARLY EVENING IN AN AREA OF MODERATE INSTABILITY WITH
VERY STEEP MID LEVEL LAPSE RATES. THIS SCENARIO WOULD SUPPORT A
LARGE HAIL AND DAMAGING WIND THREAT MAINLY ACROSS NORTHWEST TEXAS.
IT NOW APPEARS THAT AS THIS FORCING SPREADS EAST...CAPPING ACROSS
NORTH TEXAS WILL RAPIDLY WEAKEN AND A CLUSTER OF THUNDERSTORMS
WILL SPREAD EAST. THE COVERAGE AND INTENSITY DOES REMAIN SOMEWHAT
IN QUESTION FARTHER EAST THOUGH DESPITE AN ERODING CAP. STORMS MAY
TEND TO BECOME ELEVATED AS THE BOUNDARY LAYER COOLS AFTER SUNSET.
WILL BE ASSESSING SOME HIGH RES GUIDANCE THROUGH EARLY AFTERNOON
AND WILL LIKELY UP POPS DURING THE OVERNIGHT TIME FRAME ACROSS
NORTH TEXAS.
DUNN
&&
.PREV DISCUSSION... /ISSUED 350 AM CDT FRI MAR 29 2013/
LATEST UPPER AIR ANALYSIS SHOWS TROUGHS OF LOW PRESSURE ACROSS
THE NORTHEASTERN CONUS AND NORTHWESTERN CANADA. A SHORTWAVE CAN
BE SEEN MOVING ONSHORE BAJA CALIFORNIA AND THIS DISTURBANCE WILL
BE THE MAIN FOCUS FOR THE NEXT 24 HOURS. ON THE SURFACE...A LOW
CENTER REMAINS POSITIONED NEAR THE TEXAS PANHANDLE WITH A TROUGH
EXTENDING TO THE EAST INTO OKLAHOMA. THE 00Z FWD RAOB INDICATED A
STOUT CAP IN PLACE AS WEST WINDS BETWEEN 700 AND 800 MB ARE
LEADING TO WARM AIR ADVECTION. THIS CAP WILL KEEP NORTH TEXAS RAIN
FREE FOR MOST OF THE DAY TODAY. THE FORECAST THEN BECOMES
PROBLEMATIC AS THE SHORTWAVE NEARS THE REGION THIS EVENING.
THE MODELS DIFFER ON THE HANDLING OF THIS SYSTEM AND THE WEAKENING
OF THE CAP BY LATE AFTERNOON. THE GFS KEEPS THE CAP IN PLACE AND
MOST OF THE AREA RAIN FREE...WHILE THE NAM/WRF/CANADIAN/ECMWF ALL
WEAKEN THE CAP TO SOME DEGREE. THE NAM IS THE MOST AGGRESSIVE
WITH THE REMOVAL OF THE CAP COMPLETELY BY 00Z. CURRENTLY ON WATER
VAPOR THE SHORTWAVE LOOKS STRONGER THAN WHAT MOST MODELS HAVE
INITIALIZED. THE DISTURBANCE IS STRONG ENOUGH THAT IT CAN BE SEEN
ON CONSTANT PV SURFACES AS THE TROPOPAUSE DESCENDS IN THE
ATMOSPHERE WITHIN THE CENTER OF THE TROUGH OF LOW PRESSURE. THE
00-HR RAP IS CURRENTLY INITIALIZING THIS TO OCCUR AT 330
MB...WHILE THE GFS AND NAM ARE AT 280 MB AND 295 MB RESPECTIVELY.
WITH THE STRONGER TROUGH...WILL HOLD MORE WEIGHT WITH THE NAMS
FORECAST OF ERODING THE CAP THIS AFTERNOON. HIGH-RES MODELS ARE
INITIALIZING THUNDERSTORM DEVELOPMENT WEST/NORTHWEST OF THE
FORECAST AREA...NEAR THE SURFACE LOW BEFORE 00Z THIS EVENING.
PREVIOUS THINKING WAS THE CAP WOULD HOLD AND THESE STORMS WOULD
WEAKEN AS THEY PROGRESSED EAST...RUNNING INTO THE CAP. IF THE CAP
DOES ERODE...THERE SHOULD BE A DECENT COVERAGE OF STORMS INTO THE
NORTHWEST ZONES AFTER 00Z. WITH CAPE VALUES NEAR 1500 J/KG AND
MODERATE SHEAR VALUES A STRONG TO MARGINALLY SEVERE STORM IS
POSSIBLE. OVERNIGHT...A COMPLEX OF STORMS IS EXPECTED TO DEVELOP
NEAR THE SURFACE TROUGH IN OKLAHOMA AND THIS ACTIVITY COULD CLIP
OUR NORTHEASTERN ZONES NEAR SUNRISE SATURDAY.
AFTER THIS SYSTEM MOVES OUT ON SATURDAY...THINK THE REMAINDER OF
THE DAY SHOULD BE RELATIVELY QUIET AS NO LARGE SCALE FORCING FOR
ASCENT IS IN PLACE. SATURDAY NIGHT...THE TROUGH THAT IS CURRENTLY
IN NORTHWESTERN CANADA WILL CONTINUE TO SLIDE SOUTHEAST AND SEND A
COLD FRONT INTO SOUTHERN OKLAHOMA. THIS FRONT COMBINING WITH
ANOTHER WEAK EMBEDDED SHORTWAVE WILL BRING MORE THUNDERSTORM
CHANCES TO MAINLY THE NORTHERN ZONES. THIS FRONTAL BOUNDARY IS
EXPECTED TO STALL NEAR THE I-20 CORRIDOR SUNDAY AFTERNOON AS THE
UPPER LOW SHIFTS EAST. WITH THE SURFACE FOCUS IN PLACE FOR THE
CWA...ADDITIONAL THUNDERSTORMS ARE POSSIBLE FOR THE AREA. CAPE
VALUES MAY EXCEED 2000 J/KG AS LOWER 60 DEWPOINTS WILL BE IN
PLACE. SHEAR IS EXPECTED TO BE WEAKER AND THIS WILL LIMIT THE
OVERALL SEVERE POTENTIAL...BUT CANT RULE OUT A STRONG OR
MARGINALLY SEVERE STORM SUNDAY AFTERNOON.
ANOTHER SOUTHWARD MOVING IMPULSE OF UPPER ENERGY OUT OF CANADA
WILL SEND A STRONGER FRONT SOUTH ON MONDAY. THIS FRONT IS EXPECTED
TO MOVE THROUGH THE CWA MONDAY EVENING AND WILL CARRY ADDITIONAL
THUNDERSTORM CHANCES WITH THE FROPA. MEDIUM RANGE GUIDANCE HAS HAD
POOR RUN-TO-RUN CONSISTENCY WITH THE HANDLING OF FEATURES BEYOND
MONDAY. THE 00Z GFS AND ECMWF ARE SIMILAR AND KEEP STRONG UPGLIDE
ON TOP OF THE FRONTAL INVERSION THROUGH TUESDAY NIGHT AND WILL
KEEP SLIGHT TO CHANCE POPS FOR LIGHT RAIN IN THE FORECAST.
AFTER A VERY ACTIVE PERIOD...THE FINAL CHANCE OF RAIN WILL COME
WHEN THE UPPER TROUGH CURRENTLY OVER THE PACIFIC OCEAN WILL SWING
THROUGH THE AREA WEDNESDAY/WEDNESDAY NIGHT. MODELS LAST NIGHT
SHOWED THIS LOW WEAKENING BEFORE IT MOVED THROUGH...BUT TONIGHT
KEEP IT AS A STRONGER CLOSED LOW. THE TRACK OF THE LOW IS
DIFFERENT BETWEEN THE GFS AND ECMWF...BUT BOTH SHOW LARGE SCALE
FORCING FOR ASCENT AND WILL FORECAST 30 POPS FOR WEDNESDAY AND
WEDNESDAY NIGHT. AGAIN...MODELS HAVE HAD A HARD TIME WITH THE
FORECAST BEYOND MONDAY AND CONFIDENCE IS NOT HIGH.
NEVERTHELESS...AN UNSETTLED WEATHER PATTERN IS EXPECTED BETWEEN
TODAY AND NEXT WEDNESDAY WITH RAIN CHANCES IN THE FORECAST EACH
DAY FOR MOST OF THE AREA. IT WONT RAIN EVERYDAY FOR ALL
LOCATIONS...BUT CHANCES ARE THERE EACH DAY.
TEMPERATURES THROUGH MONDAY WILL BE IN THE 70S/80S FOR HIGHS WITH
LOWS IN THE 50S/60S. AFTER MONDAY...TEMPERATURES WILL BE
DRASTICALLY COLDER BEHIND THE FRONT. HIGHS BEHIND THE FRONT
TUESDAY AND WEDNESDAY WILL BE IN THE 40S/50S FOR HIGHS WITH LITTLE
DIURNAL RANGE GIVEN THE CLOUD COVER AND RAIN CHANCES. SOUTH WINDS
WILL RETURN BY THE END OF THE WEEK AND MODERATING TEMPERATURES CAN
BE EXPECTED.
HAMPSHIRE
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 77 62 80 62 76 / 10 30 20 40 40
WACO, TX 77 61 79 64 79 / 5 20 20 20 40
PARIS, TX 73 58 75 60 74 / 20 50 30 50 40
DENTON, TX 75 61 80 58 75 / 10 30 20 40 40
MCKINNEY, TX 75 61 80 60 76 / 10 30 20 40 40
DALLAS, TX 77 62 81 63 76 / 10 30 20 40 40
TERRELL, TX 76 62 79 63 75 / 10 30 20 30 40
CORSICANA, TX 76 60 77 62 78 / 10 20 20 20 40
TEMPLE, TX 76 61 78 62 81 / 5 10 20 20 30
MINERAL WELLS, TX 77 57 83 59 78 / 10 40 20 30 40
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
75/
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1118 AM CDT FRI MAR 29 2013
.UPDATE...
CURRENT FORECAST THROUGH THIS AFTERNOON IS IN GOOD SHAPE AND WILL
ONLY MAKE SOME MINOR ADJUSTMENTS TO THE HOURLY GRIDDED DATA.
SURFACE ANALYSIS INDICATES A WEAK LOW PRESSURE CENTER ACROSS THE
TEXAS PANHANDLE THIS MORNING WITH A STATIONARY FRONTAL BOUNDARY
EXTENDING EASTWARD ACROSS CENTRAL OKLAHOMA. STRONG LOW LEVEL WARM
ADVECTION HAS AIDED IN A CLUSTER OF SHOWERS AND ELEVATED
THUNDERSTORMS ACROSS CENTRAL OKLAHOMA. THESE SHOULD PRIMARILY
CONTINUE TO MOVE EAST/SOUTHEAST THROUGH THE DAY WITH A GENERAL
WEAKENING TREND AS LOW LEVEL FLOW BACKS AND WEAKENS OVER THE NEXT
SEVERAL HOURS. FARTHER SOUTH...SOME SHOWERS ARE APPROACHING THE
NORTHWEST COUNTIES. THIS ACTIVITY SHOULD REMAIN IN THE FORM OF
SHOWERS AS A STRONG CAPPING INVERSION IS PRESENT ACROSS NORTH
TEXAS AT THE PRESENT TIME.
FOCUS QUICKLY TURNS TO AN APPROACHING MID LEVEL DISTURBANCE
CURRENTLY ENTERING NEW MEXICO. THIS FEATURE INITIALLY WAS NOT
SAMPLED WELL BY THE GUIDANCE AS IT WAS OFF THE COAST OF BAJA
CALIFORNIA. IT SHOWED UP BETTER IN THE 12Z UPPER AIR ANALYSIS AS A
MID LEVEL COLD POCKET OVER TUCSON ARIZONA THIS MORNING AND NOW
APPEARS TO BE APPROACHING FAR WEST TEXAS. 12Z GUIDANCE APPEARS TO
GENERATE SIGNIFICANTLY MORE FORCING FOR ASCENT WITH THIS FEATURE
THIS AFTERNOON DURING PEAK HEATING. BY 00Z A DRYLINE SHOULD BE
LOCATED ACROSS THE PANHANDLE AS THE STRONGEST FORCING OVERSPREADS
IT. SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP BY LATE
AFTERNOON/EARLY EVENING IN AN AREA OF MODERATE INSTABILITY WITH
VERY STEEP MID LEVEL LAPSE RATES. THIS SCENARIO WOULD SUPPORT A
LARGE HAIL AND DAMAGING WIND THREAT MAINLY ACROSS NORTHWEST TEXAS.
IT NOW APPEARS THAT AS THIS FORCING SPREADS EAST...CAPPING ACROSS
NORTH TEXAS WILL RAPIDLY WEAKEN AND A CLUSTER OF THUNDERSTORMS
WILL SPREAD EAST. THE COVERAGE AND INTENSITY DOES REMAIN SOMEWHAT
IN QUESTION FARTHER EAST THOUGH DESPITE AN ERODING CAP. STORMS MAY
TEND TO BECOME ELEVATED AS THE BOUNDARY LAYER COOLS AFTER SUNSET.
WILL BE ASSESSING SOME HIGH RES GUIDANCE THROUGH EARLY AFTERNOON
AND WILL LIKELY UP POPS DURING THE OVERNIGHT TIMEFRAME ACROSS
NORTH TEXAS.
DUNN
&&
.AVIATION...
MVFR CEILINGS ARE EXPECTED THROUGH 18-19Z BEFORE CLOUDS LIFT
ABOVE 3000 FEET. SOUTH WINDS 10-16 KNOTS WILL PREVAIL. SHOWERS
AND THUNDERSTORMS ARE EXPECTED TO DEVELOP TO THE NORTHWEST OF
NORTH TEXAS LATE AFTERNOON/EARLY EVENING AND THEN MOVE SOUTHEAST
TONIGHT. THE CHANCES ARE NOT HIGH ENOUGH TO MENTION TSRA IN THE
TAFS AT THIS TIME...BUT HAVE PLACED VCSH IN THE METROPLEX TAFS
SITES FOR THE 03Z THROUGH 08Z PERIOD. MVFR CEILINGS ARE EXPECTED
TO SPREAD BACK NORTH AFTER 07Z AT WACO...AND AFTER 08Z IN THE
METROPLEX.
58
&&
.PREV DISCUSSION... /ISSUED 350 AM CDT FRI MAR 29 2013/
LATEST UPPER AIR ANALYSIS SHOWS TROUGHS OF LOW PRESSURE ACROSS
THE NORTHEASTERN CONUS AND NORTHWESTERN CANADA. A SHORTWAVE CAN
BE SEEN MOVING ONSHORE BAJA CALIFORNIA AND THIS DISTURBANCE WILL
BE THE MAIN FOCUS FOR THE NEXT 24 HOURS. ON THE SURFACE...A LOW
CENTER REMAINS POSITIONED NEAR THE TEXAS PANHANDLE WITH A TROUGH
EXTENDING TO THE EAST INTO OKLAHOMA. THE 00Z FWD RAOB INDICATED A
STOUT CAP IN PLACE AS WEST WINDS BETWEEN 700 AND 800 MB ARE
LEADING TO WARM AIR ADVECTION. THIS CAP WILL KEEP NORTH TEXAS RAIN
FREE FOR MOST OF THE DAY TODAY. THE FORECAST THEN BECOMES
PROBLEMATIC AS THE SHORTWAVE NEARS THE REGION THIS EVENING.
THE MODELS DIFFER ON THE HANDLING OF THIS SYSTEM AND THE WEAKENING
OF THE CAP BY LATE AFTERNOON. THE GFS KEEPS THE CAP IN PLACE AND
MOST OF THE AREA RAIN FREE...WHILE THE NAM/WRF/CANADIAN/ECMWF ALL
WEAKEN THE CAP TO SOME DEGREE. THE NAM IS THE MOST AGGRESSIVE
WITH THE REMOVAL OF THE CAP COMPLETELY BY 00Z. CURRENTLY ON WATER
VAPOR THE SHORTWAVE LOOKS STRONGER THAN WHAT MOST MODELS HAVE
INITIALIZED. THE DISTURBANCE IS STRONG ENOUGH THAT IT CAN BE SEEN
ON CONSTANT PV SURFACES AS THE TROPOPAUSE DESCENDS IN THE
ATMOSPHERE WITHIN THE CENTER OF THE TROUGH OF LOW PRESSURE. THE
00-HR RAP IS CURRENTLY INITIALIZING THIS TO OCCUR AT 330
MB...WHILE THE GFS AND NAM ARE AT 280 MB AND 295 MB RESPECTIVELY.
WITH THE STRONGER TROUGH...WILL HOLD MORE WEIGHT WITH THE NAMS
FORECAST OF ERODING THE CAP THIS AFTERNOON. HIGH-RES MODELS ARE
INITIALIZING THUNDERSTORM DEVELOPMENT WEST/NORTHWEST OF THE
FORECAST AREA...NEAR THE SURFACE LOW BEFORE 00Z THIS EVENING.
PREVIOUS THINKING WAS THE CAP WOULD HOLD AND THESE STORMS WOULD
WEAKEN AS THEY PROGRESSED EAST...RUNNING INTO THE CAP. IF THE CAP
DOES ERODE...THERE SHOULD BE A DECENT COVERAGE OF STORMS INTO THE
NORTHWEST ZONES AFTER 00Z. WITH CAPE VALUES NEAR 1500 J/KG AND
MODERATE SHEAR VALUES A STRONG TO MARGINALLY SEVERE STORM IS
POSSIBLE. OVERNIGHT...A COMPLEX OF STORMS IS EXPECTED TO DEVELOP
NEAR THE SURFACE TROUGH IN OKLAHOMA AND THIS ACTIVITY COULD CLIP
OUR NORTHEASTERN ZONES NEAR SUNRISE SATURDAY.
AFTER THIS SYSTEM MOVES OUT ON SATURDAY...THINK THE REMAINDER OF
THE DAY SHOULD BE RELATIVELY QUIET AS NO LARGE SCALE FORCING FOR
ASCENT IS IN PLACE. SATURDAY NIGHT...THE TROUGH THAT IS CURRENTLY
IN NORTHWESTERN CANADA WILL CONTINUE TO SLIDE SOUTHEAST AND SEND A
COLD FRONT INTO SOUTHERN OKLAHOMA. THIS FRONT COMBINING WITH
ANOTHER WEAK EMBEDDED SHORTWAVE WILL BRING MORE THUNDERSTORM
CHANCES TO MAINLY THE NORTHERN ZONES. THIS FRONTAL BOUNDARY IS
EXPECTED TO STALL NEAR THE I-20 CORRIDOR SUNDAY AFTERNOON AS THE
UPPER LOW SHIFTS EAST. WITH THE SURFACE FOCUS IN PLACE FOR THE
CWA...ADDITIONAL THUNDERSTORMS ARE POSSIBLE FOR THE AREA. CAPE
VALUES MAY EXCEED 2000 J/KG AS LOWER 60 DEWPOINTS WILL BE IN
PLACE. SHEAR IS EXPECTED TO BE WEAKER AND THIS WILL LIMIT THE
OVERALL SEVERE POTENTIAL...BUT CANT RULE OUT A STRONG OR
MARGINALLY SEVERE STORM SUNDAY AFTERNOON.
ANOTHER SOUTHWARD MOVING IMPULSE OF UPPER ENERGY OUT OF CANADA
WILL SEND A STRONGER FRONT SOUTH ON MONDAY. THIS FRONT IS EXPECTED
TO MOVE THROUGH THE CWA MONDAY EVENING AND WILL CARRY ADDITIONAL
THUNDERSTORM CHANCES WITH THE FROPA. MEDIUM RANGE GUIDANCE HAS HAD
POOR RUN-TO-RUN CONSISTENCY WITH THE HANDLING OF FEATURES BEYOND
MONDAY. THE 00Z GFS AND ECMWF ARE SIMILAR AND KEEP STRONG UPGLIDE
ON TOP OF THE FRONTAL INVERSION THROUGH TUESDAY NIGHT AND WILL
KEEP SLIGHT TO CHANCE POPS FOR LIGHT RAIN IN THE FORECAST.
AFTER A VERY ACTIVE PERIOD...THE FINAL CHANCE OF RAIN WILL COME
WHEN THE UPPER TROUGH CURRENTLY OVER THE PACIFIC OCEAN WILL SWING
THROUGH THE AREA WEDNESDAY/WEDNESDAY NIGHT. MODELS LAST NIGHT
SHOWED THIS LOW WEAKENING BEFORE IT MOVED THROUGH...BUT TONIGHT
KEEP IT AS A STRONGER CLOSED LOW. THE TRACK OF THE LOW IS
DIFFERENT BETWEEN THE GFS AND ECMWF...BUT BOTH SHOW LARGE SCALE
FORCING FOR ASCENT AND WILL FORECAST 30 POPS FOR WEDNESDAY AND
WEDNESDAY NIGHT. AGAIN...MODELS HAVE HAD A HARD TIME WITH THE
FORECAST BEYOND MONDAY AND CONFIDENCE IS NOT HIGH.
NEVERTHELESS...AN UNSETTLED WEATHER PATTERN IS EXPECTED BETWEEN
TODAY AND NEXT WEDNESDAY WITH RAIN CHANCES IN THE FORECAST EACH
DAY FOR MOST OF THE AREA. IT WONT RAIN EVERYDAY FOR ALL
LOCATIONS...BUT CHANCES ARE THERE EACH DAY.
TEMPERATURES THROUGH MONDAY WILL BE IN THE 70S/80S FOR HIGHS WITH
LOWS IN THE 50S/60S. AFTER MONDAY...TEMPERATURES WILL BE
DRASTICALLY COLDER BEHIND THE FRONT. HIGHS BEHIND THE FRONT
TUESDAY AND WEDNESDAY WILL BE IN THE 40S/50S FOR HIGHS WITH LITTLE
DIURNAL RANGE GIVEN THE CLOUD COVER AND RAIN CHANCES. SOUTH WINDS
WILL RETURN BY THE END OF THE WEEK AND MODERATING TEMPERATURES CAN
BE EXPECTED.
HAMPSHIRE
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 77 62 80 62 76 / 10 30 20 40 40
WACO, TX 77 61 79 64 79 / 5 20 20 20 40
PARIS, TX 73 58 75 60 74 / 20 50 30 50 40
DENTON, TX 75 61 80 58 75 / 10 30 20 40 40
MCKINNEY, TX 75 61 80 60 76 / 10 30 20 40 40
DALLAS, TX 77 62 81 63 76 / 10 30 20 40 40
TERRELL, TX 76 62 79 63 75 / 10 30 20 30 40
CORSICANA, TX 76 60 77 62 78 / 10 20 20 20 40
TEMPLE, TX 76 61 78 62 81 / 5 10 20 20 30
MINERAL WELLS, TX 77 57 83 59 78 / 10 40 20 30 40
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
630 AM CDT FRI MAR 29 2013
.AVIATION...
MVFR CEILINGS ARE EXPECTED THROUGH 18-19Z BEFORE CLOUDS LIFT
ABOVE 3000 FEET. SOUTH WINDS 10-16 KNOTS WILL PREVAIL. SHOWERS
AND THUNDERSTORMS ARE EXPECTED TO DEVELOP TO THE NORTHWEST OF
NORTH TEXAS LATE AFTERNOON/EARLY EVENING AND THEN MOVE SOUTHEAST
TONIGHT. THE CHANCES ARE NOT HIGH ENOUGH TO MENTION TSRA IN THE
TAFS AT THIS TIME...BUT HAVE PLACED VCSH IN THE METROPLEX TAFS
SITES FOR THE 03Z THROUGH 08Z PERIOD. MVFR CEILINGS ARE EXPECTED
TO SPREAD BACK NORTH AFTER 07Z AT WACO...AND AFTER 08Z IN THE
METROPLEX.
58
&&
.PREV DISCUSSION... /ISSUED 350 AM CDT FRI MAR 29 2013/
LATEST UPPER AIR ANALYSIS SHOWS TROUGHS OF LOW PRESSURE ACROSS
THE NORTHEASTERN CONUS AND NORTHWESTERN CANADA. A SHORTWAVE CAN
BE SEEN MOVING ONSHORE BAJA CALIFORNIA AND THIS DISTURBANCE WILL
BE THE MAIN FOCUS FOR THE NEXT 24 HOURS. ON THE SURFACE...A LOW
CENTER REMAINS POSITIONED NEAR THE TEXAS PANHANDLE WITH A TROUGH
EXTENDING TO THE EAST INTO OKLAHOMA. THE 00Z FWD RAOB INDICATED A
STOUT CAP IN PLACE AS WEST WINDS BETWEEN 700 AND 800 MB ARE
LEADING TO WARM AIR ADVECTION. THIS CAP WILL KEEP NORTH TEXAS RAIN
FREE FOR MOST OF THE DAY TODAY. THE FORECAST THEN BECOMES
PROBLEMATIC AS THE SHORTWAVE NEARS THE REGION THIS EVENING.
THE MODELS DIFFER ON THE HANDLING OF THIS SYSTEM AND THE WEAKENING
OF THE CAP BY LATE AFTERNOON. THE GFS KEEPS THE CAP IN PLACE AND
MOST OF THE AREA RAIN FREE...WHILE THE NAM/WRF/CANADIAN/ECMWF ALL
WEAKEN THE CAP TO SOME DEGREE. THE NAM IS THE MOST AGGRESSIVE
WITH THE REMOVAL OF THE CAP COMPLETELY BY 00Z. CURRENTLY ON WATER
VAPOR THE SHORTWAVE LOOKS STRONGER THAN WHAT MOST MODELS HAVE
INITIALIZED. THE DISTURBANCE IS STRONG ENOUGH THAT IT CAN BE SEEN
ON CONSTANT PV SURFACES AS THE TROPOPAUSE DESCENDS IN THE
ATMOSPHERE WITHIN THE CENTER OF THE TROUGH OF LOW PRESSURE. THE
00-HR RAP IS CURRENTLY INITIALIZING THIS TO OCCUR AT 330
MB...WHILE THE GFS AND NAM ARE AT 280 MB AND 295 MB RESPECTIVELY.
WITH THE STRONGER TROUGH...WILL HOLD MORE WEIGHT WITH THE NAMS
FORECAST OF ERODING THE CAP THIS AFTERNOON. HIGH-RES MODELS ARE
INITIALIZING THUNDERSTORM DEVELOPMENT WEST/NORTHWEST OF THE
FORECAST AREA...NEAR THE SURFACE LOW BEFORE 00Z THIS EVENING.
PREVIOUS THINKING WAS THE CAP WOULD HOLD AND THESE STORMS WOULD
WEAKEN AS THEY PROGRESSED EAST...RUNNING INTO THE CAP. IF THE CAP
DOES ERODE...THERE SHOULD BE A DECENT COVERAGE OF STORMS INTO THE
NORTHWEST ZONES AFTER 00Z. WITH CAPE VALUES NEAR 1500 J/KG AND
MODERATE SHEAR VALUES A STRONG TO MARGINALLY SEVERE STORM IS
POSSIBLE. OVERNIGHT...A COMPLEX OF STORMS IS EXPECTED TO DEVELOP
NEAR THE SURFACE TROUGH IN OKLAHOMA AND THIS ACTIVITY COULD CLIP
OUR NORTHEASTERN ZONES NEAR SUNRISE SATURDAY.
AFTER THIS SYSTEM MOVES OUT ON SATURDAY...THINK THE REMAINDER OF
THE DAY SHOULD BE RELATIVELY QUIET AS NO LARGE SCALE FORCING FOR
ASCENT IS IN PLACE. SATURDAY NIGHT...THE TROUGH THAT IS CURRENTLY
IN NORTHWESTERN CANADA WILL CONTINUE TO SLIDE SOUTHEAST AND SEND A
COLD FRONT INTO SOUTHERN OKLAHOMA. THIS FRONT COMBINING WITH
ANOTHER WEAK EMBEDDED SHORTWAVE WILL BRING MORE THUNDERSTORM
CHANCES TO MAINLY THE NORTHERN ZONES. THIS FRONTAL BOUNDARY IS
EXPECTED TO STALL NEAR THE I-20 CORRIDOR SUNDAY AFTERNOON AS THE
UPPER LOW SHIFTS EAST. WITH THE SURFACE FOCUS IN PLACE FOR THE
CWA...ADDITIONAL THUNDERSTORMS ARE POSSIBLE FOR THE AREA. CAPE
VALUES MAY EXCEED 2000 J/KG AS LOWER 60 DEWPOINTS WILL BE IN
PLACE. SHEAR IS EXPECTED TO BE WEAKER AND THIS WILL LIMIT THE
OVERALL SEVERE POTENTIAL...BUT CANT RULE OUT A STRONG OR
MARGINALLY SEVERE STORM SUNDAY AFTERNOON.
ANOTHER SOUTHWARD MOVING IMPULSE OF UPPER ENERGY OUT OF CANADA
WILL SEND A STRONGER FRONT SOUTH ON MONDAY. THIS FRONT IS EXPECTED
TO MOVE THROUGH THE CWA MONDAY EVENING AND WILL CARRY ADDITIONAL
THUNDERSTORM CHANCES WITH THE FROPA. MEDIUM RANGE GUIDANCE HAS HAD
POOR RUN-TO-RUN CONSISTENCY WITH THE HANDLING OF FEATURES BEYOND
MONDAY. THE 00Z GFS AND ECMWF ARE SIMILAR AND KEEP STRONG UPGLIDE
ON TOP OF THE FRONTAL INVERSION THROUGH TUESDAY NIGHT AND WILL
KEEP SLIGHT TO CHANCE POPS FOR LIGHT RAIN IN THE FORECAST.
AFTER A VERY ACTIVE PERIOD...THE FINAL CHANCE OF RAIN WILL COME
WHEN THE UPPER TROUGH CURRENTLY OVER THE PACIFIC OCEAN WILL SWING
THROUGH THE AREA WEDNESDAY/WEDNESDAY NIGHT. MODELS LAST NIGHT
SHOWED THIS LOW WEAKENING BEFORE IT MOVED THROUGH...BUT TONIGHT
KEEP IT AS A STRONGER CLOSED LOW. THE TRACK OF THE LOW IS
DIFFERENT BETWEEN THE GFS AND ECMWF...BUT BOTH SHOW LARGE SCALE
FORCING FOR ASCENT AND WILL FORECAST 30 POPS FOR WEDNESDAY AND
WEDNESDAY NIGHT. AGAIN...MODELS HAVE HAD A HARD TIME WITH THE
FORECAST BEYOND MONDAY AND CONFIDENCE IS NOT HIGH.
NEVERTHELESS...AN UNSETTLED WEATHER PATTERN IS EXPECTED BETWEEN
TODAY AND NEXT WEDNESDAY WITH RAIN CHANCES IN THE FORECAST EACH
DAY FOR MOST OF THE AREA. IT WONT RAIN EVERYDAY FOR ALL
LOCATIONS...BUT CHANCES ARE THERE EACH DAY.
TEMPERATURES THROUGH MONDAY WILL BE IN THE 70S/80S FOR HIGHS WITH
LOWS IN THE 50S/60S. AFTER MONDAY...TEMPERATURES WILL BE
DRASTICALLY COLDER BEHIND THE FRONT. HIGHS BEHIND THE FRONT
TUESDAY AND WEDNESDAY WILL BE IN THE 40S/50S FOR HIGHS WITH LITTLE
DIURNAL RANGE GIVEN THE CLOUD COVER AND RAIN CHANCES. SOUTH WINDS
WILL RETURN BY THE END OF THE WEEK AND MODERATING TEMPERATURES CAN
BE EXPECTED.
HAMPSHIRE
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 77 62 80 62 76 / 10 30 20 40 40
WACO, TX 77 61 79 64 79 / 5 20 20 20 40
PARIS, TX 73 58 75 60 74 / 20 50 30 50 40
DENTON, TX 75 61 80 58 75 / 10 30 20 40 40
MCKINNEY, TX 75 61 80 60 76 / 10 30 20 40 40
DALLAS, TX 77 62 81 63 76 / 10 30 20 40 40
TERRELL, TX 76 62 79 63 75 / 10 30 20 30 40
CORSICANA, TX 76 60 77 62 78 / 10 20 20 20 40
TEMPLE, TX 76 61 78 62 81 / 5 10 20 20 30
MINERAL WELLS, TX 77 57 83 59 78 / 10 40 20 30 40
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
58/85
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
350 AM CDT FRI MAR 29 2013
.DISCUSSION...
LATEST UPPER AIR ANALYSIS SHOWS TROUGHS OF LOW PRESSURE ACROSS
THE NORTHEASTERN CONUS AND NORTHWESTERN CANADA. A SHORTWAVE CAN
BE SEEN MOVING ONSHORE BAJA CALIFORNIA AND THIS DISTURBANCE WILL
BE THE MAIN FOCUS FOR THE NEXT 24 HOURS. ON THE SURFACE...A LOW
CENTER REMAINS POSITIONED NEAR THE TEXAS PANHANDLE WITH A TROUGH
EXTENDING TO THE EAST INTO OKLAHOMA. THE 00Z FWD RAOB INDICATED A
STOUT CAP IN PLACE AS WEST WINDS BETWEEN 700 AND 800 MB ARE
LEADING TO WARM AIR ADVECTION. THIS CAP WILL KEEP NORTH TEXAS RAIN
FREE FOR MOST OF THE DAY TODAY. THE FORECAST THEN BECOMES
PROBLEMATIC AS THE SHORTWAVE NEARS THE REGION THIS EVENING.
THE MODELS DIFFER ON THE HANDLING OF THIS SYSTEM AND THE WEAKENING
OF THE CAP BY LATE AFTERNOON. THE GFS KEEPS THE CAP IN PLACE AND
MOST OF THE AREA RAIN FREE...WHILE THE NAM/WRF/CANADIAN/ECMWF ALL
WEAKEN THE CAP TO SOME DEGREE. THE NAM IS THE MOST AGGRESSIVE
WITH THE REMOVAL OF THE CAP COMPLETELY BY 00Z. CURRENTLY ON WATER
VAPOR THE SHORTWAVE LOOKS STRONGER THAN WHAT MOST MODELS HAVE
INITIALIZED. THE DISTURBANCE IS STRONG ENOUGH THAT IT CAN BE SEEN
ON CONSTANT PV SURFACES AS THE TROPOPAUSE DESCENDS IN THE
ATMOSPHERE WITHIN THE CENTER OF THE TROUGH OF LOW PRESSURE. THE
00-HR RAP IS CURRENTLY INITIALIZING THIS TO OCCUR AT 330
MB...WHILE THE GFS AND NAM ARE AT 280 MB AND 295 MB RESPECTIVELY.
WITH THE STRONGER TROUGH...WILL HOLD MORE WEIGHT WITH THE NAMS
FORECAST OF ERODING THE CAP THIS AFTERNOON. HIGH-RES MODELS ARE
INITIALIZING THUNDERSTORM DEVELOPMENT WEST/NORTHWEST OF THE
FORECAST AREA...NEAR THE SURFACE LOW BEFORE 00Z THIS EVENING.
PREVIOUS THINKING WAS THE CAP WOULD HOLD AND THESE STORMS WOULD
WEAKEN AS THEY PROGRESSED EAST...RUNNING INTO THE CAP. IF THE CAP
DOES ERODE...THERE SHOULD BE A DECENT COVERAGE OF STORMS INTO THE
NORTHWEST ZONES AFTER 00Z. WITH CAPE VALUES NEAR 1500 J/KG AND
MODERATE SHEAR VALUES A STRONG TO MARGINALLY SEVERE STORM IS
POSSIBLE. OVERNIGHT...A COMPLEX OF STORMS IS EXPECTED TO DEVELOP
NEAR THE SURFACE TROUGH IN OKLAHOMA AND THIS ACTIVITY COULD CLIP
OUR NORTHEASTERN ZONES NEAR SUNRISE SATURDAY.
AFTER THIS SYSTEM MOVES OUT ON SATURDAY...THINK THE REMAINDER OF
THE DAY SHOULD BE RELATIVELY QUIET AS NO LARGE SCALE FORCING FOR
ASCENT IS IN PLACE. SATURDAY NIGHT...THE TROUGH THAT IS CURRENTLY
IN NORTHWESTERN CANADA WILL CONTINUE TO SLIDE SOUTHEAST AND SEND A
COLD FRONT INTO SOUTHERN OKLAHOMA. THIS FRONT COMBINING WITH
ANOTHER WEAK EMBEDDED SHORTWAVE WILL BRING MORE THUNDERSTORM
CHANCES TO MAINLY THE NORTHERN ZONES. THIS FRONTAL BOUNDARY IS
EXPECTED TO STALL NEAR THE I-20 CORRIDOR SUNDAY AFTERNOON AS THE
UPPER LOW SHIFTS EAST. WITH THE SURFACE FOCUS IN PLACE FOR THE
CWA...ADDITIONAL THUNDERSTORMS ARE POSSIBLE FOR THE AREA. CAPE
VALUES MAY EXCEED 2000 J/KG AS LOWER 60 DEWPOINTS WILL BE IN
PLACE. SHEAR IS EXPECTED TO BE WEAKER AND THIS WILL LIMIT THE
OVERALL SEVERE POTENTIAL...BUT CANT RULE OUT A STRONG OR
MARGINALLY SEVERE STORM SUNDAY AFTERNOON.
ANOTHER SOUTHWARD MOVING IMPULSE OF UPPER ENERGY OUT OF CANADA
WILL SEND A STRONGER FRONT SOUTH ON MONDAY. THIS FRONT IS EXPECTED
TO MOVE THROUGH THE CWA MONDAY EVENING AND WILL CARRY ADDITIONAL
THUNDERSTORM CHANCES WITH THE FROPA. MEDIUM RANGE GUIDANCE HAS HAD
POOR RUN-TO-RUN CONSISTENCY WITH THE HANDLING OF FEATURES BEYOND
MONDAY. THE 00Z GFS AND ECMWF ARE SIMILAR AND KEEP STRONG UPGLIDE
ON TOP OF THE FRONTAL INVERSION THROUGH TUESDAY NIGHT AND WILL
KEEP SLIGHT TO CHANCE POPS FOR LIGHT RAIN IN THE FORECAST.
AFTER A VERY ACTIVE PERIOD...THE FINAL CHANCE OF RAIN WILL COME
WHEN THE UPPER TROUGH CURRENTLY OVER THE PACIFIC OCEAN WILL SWING
THROUGH THE AREA WEDNESDAY/WEDNESDAY NIGHT. MODELS LAST NIGHT
SHOWED THIS LOW WEAKENING BEFORE IT MOVED THROUGH...BUT TONIGHT
KEEP IT AS A STRONGER CLOSED LOW. THE TRACK OF THE LOW IS
DIFFERENT BETWEEN THE GFS AND ECMWF...BUT BOTH SHOW LARGE SCALE
FORCING FOR ASCENT AND WILL FORECAST 30 POPS FOR WEDNESDAY AND
WEDNESDAY NIGHT. AGAIN...MODELS HAVE HAD A HARD TIME WITH THE
FORECAST BEYOND MONDAY AND CONFIDENCE IS NOT HIGH.
NEVERTHELESS...AN UNSETTLED WEATHER PATTERN IS EXPECTED BETWEEN
TODAY AND NEXT WEDNESDAY WITH RAIN CHANCES IN THE FORECAST EACH
DAY FOR MOST OF THE AREA. IT WONT RAIN EVERYDAY FOR ALL
LOCATIONS...BUT CHANCES ARE THERE EACH DAY.
TEMPERATURES THROUGH MONDAY WILL BE IN THE 70S/80S FOR HIGHS WITH
LOWS IN THE 50S/60S. AFTER MONDAY...TEMPERATURES WILL BE
DRASTICALLY COLDER BEHIND THE FRONT. HIGHS BEHIND THE FRONT
TUESDAY AND WEDNESDAY WILL BE IN THE 40S/50S FOR HIGHS WITH LITTLE
DIURNAL RANGE GIVEN THE CLOUD COVER AND RAIN CHANCES. SOUTH WINDS
WILL RETURN BY THE END OF THE WEEK AND MODERATING TEMPERATURES CAN
BE EXPECTED.
HAMPSHIRE
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 77 62 80 62 76 / 10 30 20 40 40
WACO, TX 77 61 79 64 79 / 5 20 20 20 40
PARIS, TX 73 58 75 60 74 / 20 50 30 50 40
DENTON, TX 75 61 80 58 75 / 10 30 20 40 40
MCKINNEY, TX 75 61 80 60 76 / 10 30 20 40 40
DALLAS, TX 77 62 81 63 76 / 10 30 20 40 40
TERRELL, TX 76 62 79 63 75 / 10 30 20 30 40
CORSICANA, TX 76 60 77 62 78 / 10 20 20 20 40
TEMPLE, TX 76 61 78 62 81 / 5 10 20 20 30
MINERAL WELLS, TX 77 57 83 59 78 / 10 40 20 30 40
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
547 PM CDT FRI MAR 29 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SATURDAY
ISSUED AT 236 PM CDT FRI MAR 29 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE
STRETCHING FROM THE SOUTHEAST CONUS TO THE WESTERN GREAT LAKES EARLY
THIS AFTERNOON. MID-LEVEL CLOUD DECK IS SLOWLY MOVING EAST OVER
WESTERN WISCONSIN AND IS APPROACHING CENTRAL WISCONSIN. A FEW
SPRINKLES HAVE BEEN REPORTED OVER MINNESOTA OUT OF THIS CLOUD DECK
BUT AIRMASS IS COMPARATIVELY DRIER OVER CENTRAL WISCONSIN...SO WILL
KEEP ANY MENTION OF SPRINKLES OUT OF THE FORECAST. SHORTWAVE
TROUGH... WHICH WILL BRING THE NEXT CHANCE OF PRECIP TOMORROW...IS
JUST ENTERING THE WESTERN DAKOTAS. AS THIS WAVE AND ATTENDANT COLD
FRONT APPROACHES...PRECIP CHANCES ARE THE MAIN FORECAST CONCERN.
TONIGHT...SURFACE HIGH PRESSURE WILL MOVE FROM THE CENTRAL TO THE
EASTERN GREAT LAKES...WHILE A SHEARED SHORTWAVE WILL PUSH A COOL
FRONT ACROSS THE NORTHERN PLAINS INTO THE NORTHERN MISSISSIPPI
VALLEY. SCT TO BKN LOW TO MID-DECK UPSTREAM WILL GRADUALLY MOVE
NORTHEAST THROUGH THE NIGHT...BUT DEEPER MOISTURE WILL NOT ARRIVE
INTO NORTHWEST WISCONSIN UNTIL LATE TONIGHT. SOUTH TO SOUTHWEST LOW
LEVEL WINDS WILL ADVECT IN DRY AIR FROM THE RECEDING AIRMASS...WHICH
WILL CAUSE LEVELS BELOW 5-6KFT TO STRUGGLE TO SATURATE. FIRST
THOUGHT WAS TO DELAY PRECIP CHANCES BECAUSE OF THIS DRY AIR...BUT AREAS
ACROSS THE NORTH MAY STILL REACH ENOUGH SATURATION FOR LIGHT RAIN TO
ARRIVE AFTER 09Z. SO WILL TREND A LITTLE SLOWER WITH THE PRECIP
CHANCES OVER CENTRAL AND NORTHEAST WISCONSIN...WHICH WILL KEEP THE
SE HALF OF THE AREA DRY BEFORE 15Z. THE DRY AIR SHOULD ALLOW TEMPS
TO FALL QUICKLY THIS EVENING AND WILL HAVE LOWS AROUND
MIDNIGHT...THEN TEMPS SHOULD RISE AS THICKENING CLOUDS ARRIVE. WET
BULB TEMPS LOOK TO BE SLIGHTLY ABOVE FREEZING OVER N-C WISCONSIN BY
THE TIME THE PRECIP ARRIVES...SO WILL KEEP A MENTION OF FREEZING
RAIN OUT OF THE FORECAST. THOUGH WILL MENTION TO THE EVENING CREW
TO WATCH TEMPS CLOSELY. LOWS IN THE UPPER 20S TO LOW 30S.
SATURDAY...WEAK SHORTWAVE WILL MOVE FROM NORTHERN MINNESOTA TO
EASTERN LAKE SUPERIOR AND WILL PUSH THE COOL FRONT ACROSS MOST OF
THE STATE EXCEPT FOR EASTERN WISCONSIN. WARM ADVECTION PRECIP OVER
NORTH-CENTRAL WISCONSIN WILL LIFT NORTH INTO THE UPPER PENINSULA
DURING THE EARLY MORNING. THEN THE 850MB THETAE AXIS WILL SHIFT
INTO CENTRAL WISCONSIN BY 15Z AND INTO EASTERN WISCONSIN AFTER 18Z.
PRECIP AMOUNTS SHOULD RANGE FROM A QUARTER TO A HALF INCH. HIGHS
MAINLY IN THE LOW TO MID 40S.
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
ISSUED AT 236 PM CDT FRI MAR 29 2013
MODELS SHOWED A COLD FRONT...THAT WAS MOVING ACROSS
WISCONSIN...EXTENDING FROM NORTHEAST TO SOUTHWEST WISCONSIN AT 00Z
SUNDAY. HAVE KEPT LIKELY POPS FOR THE SOUTHEAST PART OF THE AREA
DURING THE EARLY PART OF THE EVENING...BUT THEN DOWN TO CHANCE
POPS BY LATE EVENING. HAVE A SLIGHT CHANCE FOR SNOW SHOWERS ACROSS
THE FAR NORTH LATE IN THE NIGHT AS COLD AIR PASSES OVER THE WARMER
LAKE SUPERIOR WATERS IN CYCLONIC FLOW. SNOW AND/OR RAIN SHOWERS
REMAIN POSSIBLE ON SUNDAY AS A SECONDARY COLD FRONT PUSHES THROUGH
WISCONSIN. THERE WILL BE A CHANCE OF SNOW SHOWERS SUNDAY NIGHT
AND MONDAY BUT THEY SHOULD MAINLY BE CONFINED TO VILAS COUNTY AS
WINDS BECOME LESS FAVORABLE FOR LAKE EFFECT IN MOST LOCATIONS.
CLOUDS AND THE COLD FRONT SHOULD KEEP TEMPERATURES MAINLY IN THE
30S IN THE FAR NORTH ON SUNDAY...AND THE ENTIRE AREA MONDAY AND
TUESDAY.
A SURFACE HIGH AND UPPER LEVEL RIDGE WILL BRING DRIER CONDITIONS
TO THE AREA FOR THE MIDDLE PART OF THE WEEK AND TEMPERATURES
SHOULD WARM UP A BIT WITH LESS CLOUD COVER. RETURN FLOW AROUND THE
HIGH SHOULD BRING NEAR NORMAL TEMPERATURES TO THE AREA ON
THURSDAY. ANOTHER SYSTEM APPROACHING THE AREA WILL BRING A SLIGHT CHANCE
OF PRECIPITATION FOR FRIDAY.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 545 PM CDT FRI MAR 29 2013
WL CARRY LOW-END LLWS IN ALL THE TAFS LATE TNGT AS SSWLY FLOW
ALOFT INCREASES. EXPECT BAND OF SHRA TO WORK ACRS THE AREA SAT.
CIGS MAY HOLD UP INITIALLY AS LOW-LEVELS WL START OUT DRY. A
BETTER CHC AT LOWER CIGS DEVELOPING IN THE WAKE OF THE MAIN RAIN
BAND AS WINDS DECR NEAR FRONTAL BOUNDARY.
&&
.HYDROLOGY...
ISSUED AT 236 PM CDT FRI MAR 29 2013
EXPECT MILD TEMPERATURES FOR THE NEXT TWO DAYS...WITH
HIGHS IN MID TO UPPER 40S OVER THE FORECAST AREA. THIS WILL CONTINUE
THE GRADUAL MELTING OF THE SNOWPACK. RAIN IS EXPECTED SATURDAY INTO
SATURDAY EVENING...WITH PCPN AMOUNTS OF A QUARTER TO HALF INCH
POSSIBLE. GIVEN THIS SCENARIO...THE EXPECTED RUNOFF SHOULD CAUSE
A GRADUAL RISE IN THE RIVERS OVER THE FORECAST AREA THIS WEEKEND.
A FEW RIVERS IN EAST CENTRAL WISCONSIN COULD EXCEED BANKFULL.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......MG
AVIATION.......SKOWRONSKI
HYDROLOGY......MPC
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND SATURDAY
ISSUED AT 236 PM CDT FRI MAR 29 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE
STRETCHING FROM THE SOUTHEAST CONUS TO THE WESTERN GREAT LAKES EARLY
THIS AFTERNOON. MID-LEVEL CLOUD DECK IS SLOWLY MOVING EAST OVER
WESTERN WISCONSIN AND IS APPROACHING CENTRAL WISCONSIN. A FEW
SPRINKLES HAVE BEEN REPORTED OVER MINNESOTA OUT OF THIS CLOUD DECK
BUT AIRMASS IS COMPARATIVELY DRIER OVER CENTRAL WISCONSIN...SO WILL
KEEP ANY MENTION OF SPRINKLES OUT OF THE FORECAST. SHORTWAVE
TROUGH... WHICH WILL BRING THE NEXT CHANCE OF PRECIP TOMORROW...IS
JUST ENTERING THE WESTERN DAKOTAS. AS THIS WAVE AND ATTENDANT COLD
FRONT APPROACHES...PRECIP CHANCES ARE THE MAIN FORECAST CONCERN.
TONIGHT...SURFACE HIGH PRESSURE WILL MOVE FROM THE CENTRAL TO THE
EASTERN GREAT LAKES...WHILE A SHEARED SHORTWAVE WILL PUSH A COOL
FRONT ACROSS THE NORTHERN PLAINS INTO THE NORTHERN MISSISSIPPI
VALLEY. SCT TO BKN LOW TO MID-DECK UPSTREAM WILL GRADUALLY MOVE
NORTHEAST THROUGH THE NIGHT...BUT DEEPER MOISTURE WILL NOT ARRIVE
INTO NORTHWEST WISCONSIN UNTIL LATE TONIGHT. SOUTH TO SOUTHWEST LOW
LEVEL WINDS WILL ADVECT IN DRY AIR FROM THE RECEDING AIRMASS...WHICH
WILL CAUSE LEVELS BELOW 5-6KFT TO STRUGGLE TO SATURATE. FIRST
THOUGHT WAS TO DELAY PRECIP CHANCES BECAUSE OF THIS DRY AIR...BUT AREAS
ACROSS THE NORTH MAY STILL REACH ENOUGH SATURATION FOR LIGHT RAIN TO
ARRIVE AFTER 09Z. SO WILL TREND A LITTLE SLOWER WITH THE PRECIP
CHANCES OVER CENTRAL AND NORTHEAST WISCONSIN...WHICH WILL KEEP THE
SE HALF OF THE AREA DRY BEFORE 15Z. THE DRY AIR SHOULD ALLOW TEMPS
TO FALL QUICKLY THIS EVENING AND WILL HAVE LOWS AROUND
MIDNIGHT...THEN TEMPS SHOULD RISE AS THICKENING CLOUDS ARRIVE. WET
BULB TEMPS LOOK TO BE SLIGHTLY ABOVE FREEZING OVER N-C WISCONSIN BY
THE TIME THE PRECIP ARRIVES...SO WILL KEEP A MENTION OF FREEZING
RAIN OUT OF THE FORECAST. THOUGH WILL MENTION TO THE EVENING CREW
TO WATCH TEMPS CLOSELY. LOWS IN THE UPPER 20S TO LOW 30S.
SATURDAY...WEAK SHORTWAVE WILL MOVE FROM NORTHERN MINNESOTA TO
EASTERN LAKE SUPERIOR AND WILL PUSH THE COOL FRONT ACROSS MOST OF
THE STATE EXCEPT FOR EASTERN WISCONSIN. WARM ADVECTION PRECIP OVER
NORTH-CENTRAL WISCONSIN WILL LIFT NORTH INTO THE UPPER PENINSULA
DURING THE EARLY MORNING. THEN THE 850MB THETAE AXIS WILL SHIFT
INTO CENTRAL WISCONSIN BY 15Z AND INTO EASTERN WISCONSIN AFTER 18Z.
PRECIP AMOUNTS SHOULD RANGE FROM A QUARTER TO A HALF INCH. HIGHS
MAINLY IN THE LOW TO MID 40S.
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
ISSUED AT 236 PM CDT FRI MAR 29 2013
MODELS SHOWED A COLD FRONT...THAT WAS MOVING ACROSS
WISCONSIN...EXTENDING FROM NORTHEAST TO SOUTHWEST WISCONSIN AT 00Z
SUNDAY. HAVE KEPT LIKELY POPS FOR THE SOUTHEAST PART OF THE AREA
DURING THE EARLY PART OF THE EVENING...BUT THEN DOWN TO CHANCE
POPS BY LATE EVENING. HAVE A SLIGHT CHANCE FOR SNOW SHOWERS ACROSS
THE FAR NORTH LATE IN THE NIGHT AS COLD AIR PASSES OVER THE WARMER
LAKE SUPERIOR WATERS IN CYCLONIC FLOW. SNOW AND/OR RAIN SHOWERS
REMAIN POSSIBLE ON SUNDAY AS A SECONDARY COLD FRONT PUSHES THROUGH
WISCONSIN. THERE WILL BE A CHANCE OF SNOW SHOWERS SUNDAY NIGHT
AND MONDAY BUT THEY SHOULD MAINLY BE CONFINED TO VILAS COUNTY AS
WINDS BECOME LESS FAVORABLE FOR LAKE EFFECT IN MOST LOCATIONS.
CLOUDS AND THE COLD FRONT SHOULD KEEP TEMPERATURES MAINLY IN THE
30S IN THE FAR NORTH ON SUNDAY...AND THE ENTIRE AREA MONDAY AND
TUESDAY.
A SURFACE HIGH AND UPPER LEVEL RIDGE WILL BRING DRIER CONDITIONS
TO THE AREA FOR THE MIDDLE PART OF THE WEEK AND TEMPERATURES
SHOULD WARM UP A BIT WITH LESS CLOUD COVER. RETURN FLOW AROUND THE
HIGH SHOULD BRING NEAR NORMAL TEMPERATURES TO THE AREA ON
THURSDAY. ANOTHER SYSTEM APPROACHING THE AREA WILL BRING A SLIGHT CHANCE
OF PRECIPITATION FOR FRIDAY.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 236 PM CDT FRI MAR 29 2013
HIGH PRESSURE WILL DRIFT SE TODAY...REACHING SOUTHERN LAKE MICHIGAN
THIS EVENING. THE HIGH WILL BRING VFR CONDITIONS TO THE FORECAST
AREA...WITH INCREASING MID-LEVEL CLOUDS DURING THE EVENING. SOUTH
TO SOUTHWEST WINDS WILL BRING AN INCREASE IN MOISTURE LATE TONIGHT...
AS AN UPPER LEVEL DISTURBANCE APPROACHES FROM THE NORTHWEST. THIS
SYSTEM WILL BRING SCT RAIN SHOWERS TO MAINLY NC WI AFTER 09Z/SAT.
&&
.HYDROLOGY...
ISSUED AT 236 PM CDT FRI MAR 29 2013
EXPECT MILD TEMPERATURES FOR THE NEXT TWO DAYS...WITH
HIGHS IN MID TO UPPER 40S OVER THE FORECAST AREA. THIS WILL CONTINUE
THE GRADUAL MELTING OF THE SNOWPACK. RAIN IS EXPECTED SATURDAY INTO
SATURDAY EVENING...WITH PCPN AMOUNTS OF A QUARTER TO HALF INCH
POSSIBLE. GIVEN THIS SCENARIO...THE EXPECTED RUNOFF SHOULD CAUSE
A GRADUAL RISE IN THE RIVERS OVER THE FORECAST AREA THIS WEEKEND.
A FEW RIVERS IN EAST CENTRAL WISCONSIN COULD EXCEED BANKFULL.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......MG
AVIATION.......MPC
HYDROLOGY......MPC
AREA FORECAST DISCUSSION...CORRECTED
NWS LA CROSSE WI
1137 PM CDT THU MAR 28 2013
.SHORT TERM...TONIGHT THROUGH SUNDAY
345 PM CDT THU MAR 28 2013
AT 3 PM...A 1028 MB SURFACE HIGH WAS CENTERED OVER SOUTHEAST
MINNESOTA...NORTHEAST IOWA...AND SOUTHWEST WISCONSIN. DESPITE
THIS HIGH PRESSURE AREA...A BROKEN DECK OF MID CLOUDS WERE LOCATED
ACROSS THIS AFOREMENTIONED AREA. THIS WAS DUE TO MODERATE WARM AIR
ADVECTION AHEAD OF A SHORT WAVE MOVING THROUGH SOUTHWEST MINNESOTA.
OVERALL THE 28.17Z RAP MODEL IS HANDLING THESE CLOUDS THE BEST.
THEY SHOW THAT THESE MID CLOUDS WILL MOVE SOUTHEAST OUT OF THE
AREA BY 29.03Z...AND THEN SOME MORE MID CLOUDS WILL MOVE BACK INTO
THE AREA FROM WESTERN MINNESOTA AND DAKOTAS AFTER 29.06Z. THESE
CLOUDS ARE THE RESULT OF SOME WARM AIR ADVECTION AHEAD OF YET
ANOTHER SHORT WAVE TROUGH MOVING OUT OF NORTH DAKOTA. SOUNDINGS
SUGGEST THAT THIS MOISTURE WILL LIMITED TO A 100 TO 150 MB LAYER
AROUND 700 MB. AS A RESULT...NOT EXPECTING ANY PRECIPITATION FROM
THIS WAVE. THIS IS IN DESPITE THE GFS TRYING TO GENERATE SOME
PRECIPITATION JUST UPSTREAM OF THE FORECAST AREA.
FROM LATE FRIDAY NIGHT INTO SATURDAY EVENING...A STRONG SHORT WAVE
TROUGH WILL MOVE SOUTHEAST THROUGH THE FORECAST AREA. AHEAD OF
THIS WAVE...THERE WILL BE MODERATE TO STRONG 290K ISENTROPIC
LIFT...AND MODERATE 925 MB TO 850 MB MOISTURE TRANSPORT. THIS WILL
RESULT IN THE DEVELOPMENT OF A BAND OF RAIN ALONG AND AHEAD OF
THIS FRONT. INSTABILITY STILL LOOKS LIMITED WITH MOST UNSTABLE
CAPES CLIMBING UP TO 100 J/KG. AS A RESULT...LEFT ISOLATED
THUNDERSTORMS IN THE FORECAST MAINLY ALONG AND SOUTH OF INTERSTATE
90. TEMPERATURES AT THE ONSET OF THIS PRECIPITATION MAY RESULT IN
A BRIEF WINTRY MIX OF FREEZING RAIN AND SLEET MAINLY NORTHEAST OF
INTERSTATE 94. THERE MAY BE A BRIEF PERIOD OF GLAZING. HOWEVER...
IT WILL SHORT-LIVED AS TEMPERATURES CLIM QUICKLY INTO THE 40S.
ON SUNDAY...A STRONG CANADIAN COLD FRONT WILL MOVE SOUTHEAST
THROUGH THE FORECAST AREA. THERE IS VERY LITTLE 925 AND 850 MB
MOISTURE TRANSPORT ASSOCIATED WITH THIS FRONT. IN THE WAKE OF THIS
FRONT...THERE WILL BE MODERATE 290K ISENTROPIC LIFT. HOWEVER
SUBSIDENCE IN THE WAKE OF THIS FRONT WILL CAUSE CONDENSATION
PRESSURE DEFICITS TO RISE INTO THE 50 TO 100 MB RANGE. AS A
RESULT...THERE IS A QUESTION ON WHETHER THERE WILL BE ENOUGH
MOISTURE FOR ANY RAIN AND SNOW SHOWERS DURING THE AFTERNOON AND
EVENING...THUS...KEPT PRECIPITATION CHANCES ON THE LOW SIDE MAINLY
NORTH OF INTERSTATE 94.
.LONG TERM...SUNDAY NIGHT THROUGH WEDNESDAY
345 PM CDT THU MAR 28 2013
FROM SUNDAY NIGHT INTO TUESDAY...IT CONTINUES TO LOOK LIKE
ANOMALOUS COLD AIR MASS WILL BE LOCATED ACROSS THE AREA. THE ECMWF
850 TEMPERATURES ARE RUNNING 1 TO 1.5 STANDARD DEVIATIONS BELOW
NORMAL ON MONDAY...AND AROUND 1 STANDARD DEVIATION BELOW NORMAL ON
TUESDAY. THIS WILL RESULT IN HIGH TEMPERATURES IN THE LOWER AND
MID 30S ON MONDAY...AND IN THE MID AND UPPER 30S ON TUESDAY.
ON WEDNESDAY...ANOTHER COLD FRONT WILL MOVE SOUTHEAST THROUGH THE
REGION. AT THIS TIME...IT LOOKS LIKE THE BEST MOISTURE AND LIFT
WILL BE TO OUR NORTH...THUS KEPT THE FORECAST DRY.
LOOKING AHEAD TO THE FIRST HALF OF APRIL...THE CFS VERSION 2
CONTINUES TO SHOW THAT THE AREA WILL SEE PREDOMINANTLY NORTHWEST
FLOW. AS A RESULT...IT CONTINUES TO SHOW COLDER-THAN-NORMAL
TEMPERATURES PERSISTING THROUGH THIS TIME PERIOD. THE MAIN REASON
FOR THIS IS THAT THE ARCTIC OSCILLATION REMAINS NEGATIVE.
&&
.AVIATION...FRIDAY
1137 PM CDT THU MAR 28 2013
QUIET VFR CONDITIONS WILL PREVAIL FOR MOST OF FRIDAY AS HIGH
PRESSURE SLOWLY RETREATS EASTWARD. JUST PATCHY MID LEVEL CLOUDS
MOVING THROUGH WESTERN GREAT LAKES AS LOW LEVEL FLOW BECOMES
SOUTHEASTERLY THROUGH THE MORNING. DEW POINTS A BIT HIGHER CLOSER TO
INTERSTATE 35 AND WITH TEMPERATURES STAYING UP COULD SEE SOME LIGHT
FOG /4-6SM BR/ DEVELOP OVER PARTS OF NORTHEAST IOWA AND SOUTHEAST
MINNESOTA. ALREADY SEEING SOME MINOR RESTRICTIONS TO VISIBILITIES
CLOSER TO SOUTH DAKOTA BORDER. SOME INCREASE IN CLOUDS NOTED AHEAD
OF CANADIAN SHORT WAVE TROUGH BY FRIDAY EVENING BUT PRECIPITATION
THREAT SHOULD HOLD OFF UNTIL AFTER 30/06Z.
&&
.HYDROLOGY...
345 PM CDT THU MAR 28 2013
DUE TO A MELTING SNOWPACK OVER THE LAST SEVERAL DAYS...MANY RIVERS
ACROSS NORTHEAST IA/SOUTHEAST MN/AND SOUTHWEST WI HAVE EXPERIENCED
WITHIN BANK RISES OF 2 TO 4 FEET. IN AREAS WHERE THE SNOW HAS
MELTED...SOME OF THE FROST HAS MELTED IN THE TOP FEW INCHES OF THE
SOIL...THIS IS ALLOWING SOME OF THE SNOW MELT TO GET INTO THE TOP
SOILS. THIS MOISTURE THEN FREEZES IN THE TOP SOILS AT NIGHT. THIS IS
LIMITING THE AMOUNT OF RUNOFF INTO THE RIVERS.
ON SATURDAY...LOOK FOR A QUARTER TO HALF INCH OF RAIN. THIS WILL
ADD ONTO THE RUNOFF FROM THE SNOW MELT. HOWEVER THE WARM RAINS
WILL HELP TO MELT SOME FROST IN THE TOP SOILS...SO NOT LOOKING FOR
COMPLETE RUNOFF LIKE WE HAD EARLIER IN THE MONTH.
WHILE NO FLOODING IS EXPECTED AT THIS TIME...PEOPLE LIVING NEAR
OR HAVING INTERESTS ALONG RIVER WAYS ARE URGED TO MONITOR LATEST
RIVER FORECASTS AND STATEMENTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
243 PM CDT THU MAR 28 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION....SHEA
HYDROLOGY...DAS/BOYNE
AREA FORECAST DISCUSSION
NWS TUCSON AZ
845 PM MST SAT MAR 30 2013
.SYNOPSIS...CLEARING TONIGHT...OTHERWISE DRY AND WARM INTO NEXT
WEEK. A LOW PRESSURE SYSTEM SKIRTING BY NORTHEAST OF THE AREA WILL
BRING A FEW DEGREES OF COOLING AND GUSTY WINDS AT TIMES THE FIRST
HALF OF THE WEEK.
&&
.DISCUSSION...FLAT RIDGE WITH MODEST WESTERLY FLOW UNDER LOW STILL
OFF THE CALIFORNIA COAST. CONSIDERABLE CLOUDINESS ABOVE H7 EARLIER
BUT NICE SECONDARY DRY SLOT ON WATER VAPOR IMAGERY PUSHING INTO
SOUTHWEST AND SOUTHERN ARIZONA THIS EVENING. WE UPDATED EARLIER TO
ACCELERATE THE OVERALL CLEARING TREND...WHILE TWEAKING SOME
OVERNIGHT LOWS DOWN A FEW DEGREES WITH MORE COMPLETE CLEARING BEFORE
SUNRISE. OTHERWISE NO SURPRISES WITH CURRENT ANALYSIS AND EARLY
LOOKS AT 00Z NAM AND DERIVATIVE SUITE TRENDS OR RECENT HRRR OUTPUT.
&&
.PREV DISCUSSION...WARM CLOUDY DAY ACROSS THE AREA WITH SOME AREAS
OF VIRGA. THE BACK EDGE OF CLOUDS HAS PUSHED THROUGH SW ARIZONA THIS
AFTERNOON AND EXPECT THIS TO PUSH EAST TONIGHT INTO EASTER SUNDAY
MORNING. THUS EXPECT A CLOUDY START TO TH EVENING THEN BECOMING
MOSTLY CLEAR TOWARD MORNING. OVERNIGHT LOWS...DUE TO LESS CLOUD
COVER...WILL BE COOLER THAN THIS MORNING.
UPPER LOW CURRENTLY SPINNING OFF CENTRAL CALIFORNIA COAST WILL
AMPLIFY RIDGE OVER THE AREA SUNDAY AS IT MOVES CLOSER TO THE BAY
AREA. UPPER LOW TO MOVE INLAND SUNDAY EVENING...THEN ACROSS NEVADA
MONDAY MORNING...ACROSS SOUTHERN UTAH MONDAY AFTERNOON/EVENING...
THE FOUR CORNERS TUESDAY MORNING...AND OVER WESTERN NEW MEXICO
TUESDAY AFTERNOON. MOISTURE RATHER LIMITED AND NEAR THE CENTER OF
THE LOW. HAVE UPPED POPS A BIT IN THE WHITES ON TUESDAY BUT STILL ON
THE SLIGHT CHANCE SIDE. COOLER TUESDAY WITH HIGHS NEAR NORMAL. SOME
BREEZES MONDAY AND TUESDAY.
WARMER THE REMAINDER OF THE WEEK AS UPPER RIDGE AMPLIFIES OVER THE
DESERT SW.
&&
.AVIATION...CLEARING FROM THE WEST...SCT-BKN ABV 12K FT AGL
EARLY...BECOMING SKC OVERNIGHT THROUGH SUNDAY. NORMAL DIURNAL WIND
TRENDS GENERALLY LESS THAN 8 KTS OVERNIGHT...BECOMING WESTERLY 10-12
KTS AND GUSTY AT TIMES SUNDAY AFTERNOON. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...CLEARING TONIGHT AND SUNDAY AS WEAK HIGH PRESSURE
ALOFT BUILDS IN. MEANWHILE...WE`RE WATCHING AN AREA OF LOW PRESSURE
ACROSS THE EASTERN PACIFIC THAT WILL TRACK TO THE NORTH OF SOUTHERN
ARIZONA EARLY THIS WEEK. THERE WILL BE A SLIGHT CHANCE OF SHOWERS IN
THE HIGHER TERRAIN OF THE WHITE MOUNTAINS TUESDAY. WINDS WILL ALSO
INCREASE AND BECOME BREEZY MAINLY MONDAY AND TUESDAY AFTERNOON.
THEREAFTER...AN AREA OF HIGH PRESSURE WILL BUILD BACK IN STARTING
WEDNESDAY THROUGH THE END OF THE WEEK WITH DRY CONDITIONS AND JUST A
FEW AFTERNOON BREEZES. TEMPERATURES WILL REMAIN ABOVE NORMAL MOST OF
THIS WEEK WITH NEAR NORMAL TEMPERATURES TUESDAY.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
MEYER
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
240 AM MDT SUN MAR 31 2013
.SHORT TERM...GENERALLY DRY NW FLOW WILL BE OVER THE AREA THRU
THIS AFTN AS SFC LOW PRES DEVELOPS OVER ERN CO. 850-700 MB TEMPS
ARE A DEGREE OR TWO WARMER THIS AFTN SO WILL KEEP HIGHS IN THE 65
TO 70 DEGREE RANGE OVER NERN CO.
FOR TONIGHT THE FLOW ALOFT WILL BECOME MORE WSW AS A WEAK UPPER
LEVEL LOW BEGINS TO MOVE TOWARDS THE GREAT BASIN. SOME MOISTURE
WILL INCREASE IN THE MTNS LATE TONIGHT SO WILL MENTION A SLIGHT
CHC OF -SHSN WEST OF THE DIVIDE AFTER MIDNIGHT. OVER NERN CO A
CDFNT WILL BACKDOOR INTO THE AREA OVERNIGHT HOWEVER OUTSIDE OF
SOME INCREASE IN LOW LVL CLOUDS AT THIS TIME DO NOT EXPECT ANY
PCPN.
.LONG TERM...MODELS SLOWER WITH WEAK UPPER LOW. NOW ITS OVER THE
FOUR CORNERS FROM 18Z TO 00Z TUESDAY AFTERNOON. IT WEAKENS AND
BECOMES AN OPEN TROUGH...ITS AXIS IS OVER EASTERN COLORADO AT 12Z
WEDNESDAY MORNING. THE FLOW ALOFT IS PRETTY WEAK ACROSS THE CWA
FROM MONDAY NIGHT THROUGH TUESDAY NIGHT. THERE IS UPWARD SYNOPTIC
SCALE ENERGY PROGGED FOR THE CWA MONDAY THROUGH TUESDAY NIGHT. THE
BOUNDARY LAYER FLOW IS PROGGED TO BE UPLSOPE MONDAY THROUGH MUCH
OF TUESDAY NIGHT...WITH EITHER EAST OR SOUTHEAST DIRECTIONS. THE
MOISTURE IS NOT AS EXTENSIVE AND PROLONGED AS PREVIOUS MODEL RUNS
INDICATED. THE QPF FIELDS DO NOT START MEASURABLE PRECIPITATION
UNTIL LATER MONDAY MORNING. MODELS SHOW MEASURABLE PRECIPITATION
INTO WEDNESDAY MORNING NOW. THE AMOUNTS ARE LESS THAN YESTERDAY`S
00Z RUNS INDICATED. SO RATHER THAN CHASING THE LATEST/GREATEST
MODELS AND AT THE RISK OF CONTINUING TO YO-YO THE FORECAST...WILL
CHANGE VERY LITTLE THROUGH TUESDAY NIGHT. TEMPERATURES LOOK
CONSIDERABLY WARMER ON MONDAY THAN YESTERDAY`S 00Z RUNS INDICATED.
MONDAY`S HIGHS ARE NOW ONLY 4-7 COOLER THAN SUNDAY`S HIGHS.
TUESDAY`S HIGHS ARE 1-3 C COOLER THAN MONDAY`S. AGAIN WILL LEAVE
THINGS STATUS QUO THIS UPDATE. FOR THE LATER DAYS...WEDNESDAY
THROUGH SATURDAY...THERE IS UPPER RIDGING INTO FRIDAY MORNING
...THEN A WEAK UPPER TROUGH MOVES ACROSS FRIDAY NIGHT...AND
MORE RIDGING SATURDAY.
&&
.AVIATION...LIGHT DRAINAGE WINDS THRU THE MORNING HOURS WILL
BECOME NWLY BY EARLY AFTN. LATEST RAP SHOWS WINDS COULD GUSTY UP
TO 20 MPH FOR A FEW HOURS BETWEEN 22Z AND 00Z BEFORE DECREASING.
TONIGTH A CDFNT WILL BACKDOOR INTO THE AREA BETWEEN 03Z AND 06Z
WITH WINDS BECOMING MORE NELY. AFTER 06Z WINDS WILL SHIFT TO LIGHT
ESE. TOWARDS 12Z MAY SEE SOME STRATUS WITH CEILINGS IN THE
2000-3000 FT RANGE.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM....RJK
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
355 AM EDT SUN MAR 31 2013
.SYNOPSIS...
07Z WATER VAPOR AND H4 RAP ANALYSIS SHOW THE BEGINNINGS OF A PATTERN
AMPLIFICATION THAT WILL OCCUR ACROSS THE EASTERN HALF OF THE CONUS
THROUGH THE EARLY PORTION OF THE WEEK. THE OVERALL PATTERN CONTINUES
TO SHOW A CONVERGENT FLOW OVER THE WESTERN THIRD OF THE NATION
FOLLOWED BY A GENERAL DOWNSTREAM WEST TO EAST REGIME. THIS WESTERLY
FLOW IS JUST NOW BEGINNING TO AMPLIFY AS A SERIES OF SHORTWAVES
EJECT SOUTHWARD FROM SOUTHERN CANADA. TWO FEATURES WITHIN THE FLOW
THAT WILL INFLUENCE OUR WEATHER THROUGH THE SHORT TERM INCLUDE A
SHORTWAVE CURRENTLY MOVING EASTWARD ALONG THE NORTHERN GULF
COAST...AND ANOTHER SHORTWAVE STILL UP OVER THE HIGH PLAINS THAT
WILL RAPIDLY PUSH TOWARD THE SOUTHEASTERN CONUS.
AT THE SURFACE...HIGH PRESSURE IS RIDGING BACK ACROSS THE PENINSULA
AND EASTERN GULF OF MEXICO FROM A POSITION NEAR THE NORTHERN BAHAMA
ISLANDS. THE RIDGE AXIS IS ACROSS THE SOUTHERN HALF OF THE PENINSULA
GIVING OUR FORECAST AREA A LIGHT SOUTHEAST TO SOUTH FLOW. AN
INCREASE IN COLUMN MOISTURE AND A LESS FAVORABLE RIDGE POSITION WILL
HELP KEEP TEMPERATURES EARLY THIS MORNING CONSIDERABLY WARMER FOR
MOST SPOTS THAN WHAT HAS BEEN EXPERIENCED THE PAST SEVERAL NIGHTS.
&&
.SHORT TERM (TODAY THROUGH TUESDAY)...
TODAY/TONIGHT...
A GENERALLY QUIET AND WARM DAY IN STORE FOR THE REGION AS WE RESIDE
BETWEEN PASSING SHORTWAVES FOR THE DAYLIGHT HOURS. HIGH PRESSURE AT
THE SURFACE WILL DOMINATE THE LOWER LEVELS AS IT RIDGES WESTWARD
ACROSS THE SOUTH-CENTRAL PENINSULA. AN AMPLIFYING UPPER LEVEL
PATTERN ACROSS THE EASTERN HALF OF THE NATION WILL PROPEL A SURFACE
COLD FRONT INTO THE SOUTHEASTERN STATES...HOWEVER IT SEEMS APPARENT
THAT THE BEST COMBINATION OF FRONTAL FOCUS AND DEEP LAYER SYNOPTIC
FORCING AHEAD OF THE APPROACHING SHORTWAVE WILL STAY NORTH AND
NORTHWEST OF THE FORECAST ZONES THROUGH THE EVENING. A LIGHT SOUTH
TO SOUTHEAST FLOW IN THE MORNING WILL TURN SOUTHWEST NEAR THE COAST
AS STRONG TERRESTRIAL HEATING FORCE SEA-BREEZE CIRCULATIONS. HIGH
TEMPERATURES WILL BE NEAR SEASONABLE NORMS FOR THE FINAL DAY OF
MARCH UNDER A MIX OF SUN AND CLOUDS. LOOKING FOR HIGHS APPROACHING
80 NORTH OF I-4 AND INTO THE LOWER 80S SOUTH AWAY FROM THE COAST.
WOULD EXPECT AFTERNOON TEMPS TO BE AT LEAST SEVERAL DEGREES COOLER
AT THE BEACHES DUE TO THE DEVELOPING ONSHORE FLOW OFF THE COOLER
SHELF WATERS...ESPECIALLY ALONG THE NATURE COAST. TONIGHT...WILL SEE
THE COLD FRONT CONTINUE TO SETTLE SOUTHWARD TO A POSITION JUST NORTH
OF I-10 BY SUNRISE. THE CLOSER PROXIMITY OF THIS BOUNDARY AND THE
SHORTWAVE WILL BRING A CHANCE FOR A FEW SHOWERS TO THE NORTHERN
NATURE COAST...MAINLY LEVY/CITRUS COUNTIES DURING THE SECOND HALF OF
THE NIGHT. HOWEVER...APPEARS THE BEST CHANCE OF SHOWER FOR THESE
ZONES WILL STILL HOLD OFF UNTIL THE DAYLIGHT HOURS OF MONDAY MORNING
WHEN THE BEST SYNOPTIC FORCING ARRIVES.
MONDAY/MONDAY NIGHT...
SURFACE RIDGE DROPS SOUTHWARD OUT OF THE AREA IN RESPONSE TO THE
ARRIVAL OF THE SURFACE FRONT ACROSS NORTHERN FLORIDA. AS MENTIONED
ABOVE...EXPECT TO SEE A SCATTERING OF SHOWERS DURING THE
MORNING/EARLY AFTERNOON HOURS TO THE NORTH OF TAMPA BAY IN RESPONSE
TO A FAVORABLE COMBINATION OF SURFACE FOCUS AND QG-FORCING. FURTHER
SOUTH...THE RAINFALL POTENTIAL IS MORE TRICKY. A BETTER MOISTURE
PROFILE... CONVERGENT INLAND FLOW AND AT LEAST SOME SYNOPTIC SUPPORT
INTO THE AFTERNOON SUGGESTS THAT AT LEAST WIDELY SCT CONVECTION MAY
FIRE ALONG THE INLAND PROPAGATING SEA-BREEZE BOUNDARY. A BIT EARLY
IN THE YEAR FOR THIS...BUT WITH THE SYNOPTIC SUPPORT...ITS NOT OUT
OF THE QUESTION. MOST AVAILABLE CONVECTION ALLOWING MODELS ARE ALSO
SHOWING THE SHOWER/ISOLATED STORM POTENTIAL...MAINLY EAST OF THE
I-75 CORRIDOR. THIS SCENARIO AND CONVECTIVE PLACEMENT MAKES SENSE
GIVEN THE QUICK INLAND MOVEMENT OF THE SEA-BREEZE. IT WOULD ALSO
SUGGEST THAT ANY ACTIVITY THAT DOES DEVELOP WILL QUICKLY TRANSLATE
TOWARD THE I-95 CORRIDOR BY LATE AFTERNOON/EARLY EVENING. WILL
ATTEMPT TO REPRESENT THIS PHILOSOPHY OF THE AREAL COVERAGE AND
TIMING IN THE POP GRIDS. MONDAY NIGHT...SURFACE FRONT QUICKLY WASHES
OUT AS IT TRIES TO MOVE SOUTH INTO THE FL PENINSULA. THIS LOSS OF
FOCUS ALONG WITH THE DEPARTURE OF THE SHORTWAVE ENERGY SHOULD BRING
A RATHER QUICK END TO ANY LINGERING SHOWERS...AND BASICALLY HAVE A
DRY OVERNIGHT PERIOD IN THE GRIDS. ONE CONCERN THAT WILL NEED TO BE
EVALUATE WITH FUTURE FORECAST PACKAGES IS THE POTENTIAL FOR SEA-FOG
DEVELOPING MONDAY AFTERNOON/EVENING...AND POSSIBLY EXPANDING ONSHORE
WITH TIME. THE LATEST SREF GUIDANCE IS QUITE AGGRESSIVE WITH THIS
SCENARIO...AND GIVEN THE HIGHER DEWPOINT AIR THAT WILL BE
ARRIVING...AND THE STILL COOL SHELF WATERS AFTER SUCH A COLD
MARCH...IT IS CERTAINLY PLAUSIBLE.
TUESDAY...
A PLEASANT AND WARM SPRING DAY LOOKS LIKELY UNDER A ZONAL FLOW
PATTERN. A MIX OF SUN AND CLOUD WILL BE FORECAST WITH TEMPERATURES
CLIMBING INTO THE 80 AWAY FROM THE BEACHES WHERE DEVELOPING ONSHORE
FLOW SHOULD ONCE AGAIN KEEP TEMPS COOLER. A FEW OF THE GLOBAL MODELS
ALONG WITH THE SREF ARE KICKING OFF THEIR CONVECTIVE PARM SCHEMES
SOUTH OF I-4 DURING THE AFTERNOON...HOWEVER...GIVEN THE TIME OF YEAR
AND LACK OF ANY SYNOPTIC FORCING...MENTIONABLE SHOWER CHANCES SEEM
UNLIKELY. WILL KEEP RAIN CHANCES OUT OF THE FORECAST FOR THE ENTIRE
AREA.
&&
.LONG TERM (TUESDAY NIGHT THROUGH NEXT SATURDAY)...THE AREA STARTS
OFF UNDER NEARLY ZONAL FLOW ALOFT...A RESULT OF A SHORT WAVE
TROUGH/LOW OVER THE FOUR CORNERS REGION AND A SECOND LOW OVER THE
LOWER SAINT LAWRENCE VALLEY. AT THE SURFACE...HIGH PRESSURE IN THE
UPPER MISSISSIPPI VALLEY RIDGES TO THE SE U.S. AS THE REMNANTS OF A
FRONTAL BOUNDARY RESIDES ACROSS FL AND THE EAST GULF OF MEXICO. AS
THE WEEK PROGRESSES THE FOUR CORNERS TROUGH/LOW TRACKS INTO THE
SOUTHERN PLAINS/WESTERN GULF COAST...FORMING A SURFACE TROUGH/LOW
OVER THE WESTERN GULF. THIS ALONG WITH THE SURFACE RIDGE THAT SHIFTS
OFFSHORE FROM THE SE U.S. WILL INCREASE LOW LEVEL FLOW AND SHIFT IT
TO SE AND SOUTHERLY. BY FRI THE UPPER TROUGH IS SOMEWHERE ALONG THE
GULF COAST WITH IT/S SURFACE REFLECTION IN THE NE GULF TO CAROLINA
COASTAL AREA. ON SAT THE UPPER TROUGH HAS REACHED THE EASTERN
SEABOARD WITH THE SURFACE FEATURE OVER ATLANTIC COAST
WATERS...TRAILING A COLD FRONT THAT WILL BE EAST OF THE STATE.
THE MODELS ARE IN GENERAL AGREEMENT WITH THE BIG PICTURE BUT
CONTINUE TO DIFFER IN MINOR DETAILS LIKE LOCATION...TIMING AND
STRENGTH. ALTHOUGH THE 31/00Z ECMWF IS NOW MORE IN LINE WITH THE
LATEST GFS THAN THE PREVIOUS ECMWF WAS. CLOUDS ALONG WITH RAIN
CHANCES WILL GRADUALLY INCREASE THEN DECREASE SHARPLY SAT. FOR NOW
HAVE KEPT JUST SHOWERS AND NO MORE THAN 50 POPS. WINDS WILL BECOME
ROBUST...BUT MAINLY A MARINE ISSUE. TEMPERATURES WILL RUN ABOVE
NORMAL ALTHOUGH THEY WILL DROP SOME FOR SAT.
&&
.AVIATION...
VFR CONDITIONS CONTINUE FOR THE NEXT 24 HOURS UNDER FEW-SCT CU OR
SC AND SCT-BKN CIRRUS. EAST AND SE WINDS BECOME ONSHORE IN THE
AFTERNOON IN THE 10-12 KT RANGE.
&&
.MARINE...
HIGH PRESSURE WILL REMAIN IN CONTROL OF THE EASTERN GULF OF MEXICO
THROUGH TONIGHT AND THEN RETREAT SOUTH AND EAST IN RESPONSE TO AN
APPROACHING COLD FRONT FROM THE NORTH. THIS FRONT WILL WASH OUT AS
IT ARRIVES OVER THE NORTHERN GULF AND BE QUICKLY REPLACED BY HIGH
PRESSURE RIDGING IN FROM THE NORTH ON TUESDAY. WINDS AND SEAS ARE
FORECAST TO REMAIN BELOW HEADLINE CRITERIA THROUGH TUESDAY.
AFTERNOON SEA-BREEZES CAN BE EXPECTED TO TURN WINDS ONSHORE NEAR
THE COAST EACH DAY.
&&
.FIRE WEATHER...
A CONTINUED SLOW INCREASE IN LOW LEVEL MOISTURE SHOULD GENERALLY
PREVENT RED FLAG CONDITIONS FROM BEING REACHED TODAY. CONDITIONS
WILL BE MARGINAL FOR POLK AND HIGHLANDS COUNTIES WHERE 3 TO 4 HOURS
CRITICAL RELATIVE HUMIDITY IS CURRENTLY FORECAST. ENOUGH MOISTURE
WILL ARRIVE BY MONDAY TO PREVENT ANY CRITICALLY LOW RELATIVE
HUMIDITY ACROSS WEST CENTRAL AND SOUTHWEST FLORIDA.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 78 63 78 63 / 0 10 20 10
FMY 83 64 84 64 / 10 10 20 10
GIF 84 61 83 60 / 10 10 40 10
SRQ 78 63 78 63 / 0 10 20 10
BKV 81 59 80 57 / 0 10 30 10
SPG 79 65 79 64 / 0 10 20 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM/AVIATION/DSS...RUDE
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
603 PM CDT SAT MAR 30 2013
...UPDATE TO AVIATION...
.SYNOPSIS...
ISSUED AT 215 PM CDT SAT MAR 30 2013
THE LONGWAVE PATTERN WAS CHARACTERIZED BY NORTHWEST FLOW FROM
WESTERN CANADA INTO THE CENTRAL CONUS. SEVERAL SHORTWAVE TROUGHS
EMBEDDED IN THE NORTHWEST FLOW PATTERN COULD BE IDENTIFIED ON WATER
VAPOR LOOP AND RAP ANALYSIS. THE DISTURBANCE WHICH LED TO LAST
NIGHT`S SEVERE WEATHER EVENT WAS LOCATED OVER MISSOURI AND ARKANSAS
EARLY THIS AFTERNOON. FARTHER UPSTREAM...ANOTHER SHORTWAVE TROUGH
WAS EVIDENT FROM WYOMING TO SOUTH DAKOTA. MEANWHILE...A FAIRLY LARGE
UPPER LOW WAS CENTERED OFF THE COAST OF CALIFORNIA DISCONNECTED FROM
THE POLAR JET STREAM FLOW. A SUBTROPICAL JET CONTAINED A FAIR AMOUNT
OF HIGH LEVEL CIRRUS IN THE LOW LATITUDES SOUTH OF THE
AFOREMENTIONED UPPER LOW INTO WESTERN MEXICO. AT THE SURFACE...A
WEAK TROUGH AXIS EXTENDED FROM NORTHEAST KANSAS INTO WESTERN
OKLAHOMA. THE NORTH TO NORTHWEST WINDS BEHIND THE TROUGH AXIS HAD
LOWER MOISTURE CONTENT WITH DEWPOINTS IN THE UPPER 30S TO LOWER 40S.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 403 PM CDT SAT MAR 30 2013
THE SHORTWAVE TROUGH MOVING SOUTHEAST ACROSS WESTERN NEBRASKA WILL
AID IN THE DEVELOPMENT OF SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS LATE THIS AFTERNOON ACROSS SOUTHWEST NEBRASKA AND
NORTHEAST COLORADO. THE AIRMASS IN THIS REGION IS DRY WITH DEWPOINT
TEMPERATURES ONLY IN THE LOWER TO MID 30S. STEEP LAPSE RATES WERE
FOUND AHEAD OF THIS SHORTWAVE TROUGH AS SURFACE TEMPERATURES WARM
INTO THE LOWER TO MID 60S...AND MID LEVEL TEMPERATURES WERE COLD
(-20 TO -22C AT 500MB, 0 TO -4C AT 700MB). THIS THERMODYNAMIC
SETTING RESULTED IN A LITTLE BIT OF CONVECTIVE INSTABILITY WITH
SBCAPE AROUND A COUPLE HUNDRED J/KG. THERE WILL BE LOOSELY ORGANIZED
SHOWERS AND EMBEDDED THUNDER MOVING SOUTHEAST FROM THE CO/NE/KS
TRI-BORDER REGION TO WESTERN/CENTRAL KANSAS LATE TONIGHT. MID LEVEL
COLD ADVECTION AND DEEP TROPOSPHERIC ASCENT AHEAD OF THE WAVE WILL
AID IN SUSTAINING SHOWER AND THUNDER ACTIVITY THROUGH THE NIGHT.
AREAS CLOSER TO CENTRAL KANSAS (I.E. ELLIS COUNTY) WILL STAND A
BETTER CHANCE AT MORE ORGANIZED CONVECTION AS REMNANT LOW LEVEL
MOISTURE WAS HANGING AROUND AFTER THE TROUGH PASSAGE FROM EARLIER
TODAY. POPS WERE RAISED TO 40 TO 50 PERCENT...ESPECIALLY IN THE
NORTHEASTERN DDC FORECAST AREA (CLOSER TO CENTRAL KANSAS).
SUBSIDENCE IN THE WAKE OF THE SHORTWAVE TROUGH WILL MOVE INTO WEST
CENTRAL KANSAS DURING THE 09-12Z TIME FRAME...AND THE SHOWER
ACTIVITY WILL MOVE INTO SOUTH CENTRAL KANSAS AND NORTHERN OKLAHOMA.
AS FAR AS TEMPERATURES GO...COLD ADVECTION WILL BE RATHER WEAK AT
THE SURFACE WITH SOME DOWNSLOPE MODIFICATION...SO LOWS TONIGHT AFTER
THE SHOWERS MOVE THROUGH WILL ONLY BOTTOM OUT IN THE UPPER 30S TO
LOWER 40S. ON SUNDAY...SUBSIDENCE WILL PREVAIL WITH WEAK SURFACE
HIGH YIELDING LIGHT WINDS THROUGH THE DAY. HIGHS WERE LOWERED JUST
A COUPLE DEGREES INTO THE UPPER 60S GIVEN THE SLIGHTLY COOLER LOWER
TROPOSPHERE BEHIND THE WAVE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 403 PM CDT SAT MAR 30 2013
A COLD CANADIAN HIGH PRESSURE WILL AGAIN INFLUENCE THE WEATHER FOR
AT LEAST THE MONDAY THROUGH WEDNESDAY TIMEFRAME. BOTH THE GFS AND
ECMWF ALLOW A SURFACE BACKDOOR COLD FRONT TO SLIDE INTO WESTERN
KANSAS SUNDAY NIGHT INTO EARLY MONDAY, BRINGING EASTERLY UPSLOPE
WINDS THAT REMAIN ESTABLISHED THROUGH ABOUT WEDNESDAY MORNING.
ADDITIONALLY, THE MODELS HAVE BEEN VERY CONSISTENT NOW FOR SEVERAL
DAYS IN DEVELOPING A PROGRESSIVE TROUGH OVER THE WESTERN UNITED
STATES WHICH DIGS INTO THE SOUTHERN ROCKIES BY TUESDAY AND TUESDAY
NIGHT. THE RESULT WILL BE AN INCREASING CHANCE OF PRECIPITATION
(EITHER RAIN/SNOW OR BOTH) FROM THE LATE MONDAY TIMEFRAME THROUGH
TUESDAY AND WEDNESDAY MORNING. WITH THE COOL AND EASTERLY UPSLOPE
EXPECTED BY MONDAY, TEMPERATURES WILL DROP 20 TO 30 DEGREES FROM
SUNDAY AFTERNOON`S LOW 70`S. STRATUS WILL LIKELY IMPEDE INSOLATION
SIGNIFICANTLY DURING THE TIMEFRAME BASED ON MODEL 925-850 MB
RELATIVE HUMIDITY FIELDS. THROUGH THE DAY THE LAYER BECOME THICKER
WITH TIME, WHICH MIGHT SUGGEST SOME LIGHT FOG OR EVEN DRIZZLE
POTENTIAL THROUGH THE OVERNIGHT SUNDAY WITH TEMPERATURES REMAINING
ABOVE FREEZING. SNOW PRECIPITATION TYPE REALLY WON`T BE DEPENDENT ON
THE ARRIVAL OF COLD ENOUGH AIR ALOFT, BUT RATHER THE MOISTENING UP OF A
DEEP ENOUGH SATURATED LAYER THROUGH THE QG-FRONTOGENESIS/ISENTROPIC
LIFTING PROCESS ON TUESDAY.
THE LATEST ECMWF MODEL RUN DEPICT THE HEAVIER SNOWFALL TO OCCUR
FARTHER SOUTHWEST OVER SOUTHEAST COLORADO AND THE PANHANDLES, THAN
THE GFS MODEL RUNS WHICH FORECASTS HEAVY SNOW ACROSS SOUTHWEST
KANSAS. AT A MINIMUM THE MODEL TRENDS LEND CONFIDENCE TO HIGHER
CHANCES FOR PRECIPITATION DURING THIS TIMEFRAME, AND INFLUENCING
COOLER TEMPERATURES FOR WEDNESDAY. THE REMAINDER OF THE WEEK SHOULD
BRING A WARMING TREND BACK TOWARD CLIMATOLOGY AS UPPER LEVEL RIDGING
TO FLAT ZONAL UPPER LEVEL FLOW AND SOUTHERLY SURFACE WINDS BECOME
RE-ESTABLISHED.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 600 PM CDT SAT MAR 30 2013
VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES THROUGH LATE THIS
EVENING. A COLD FRONT IS THEN EXPECTED TO PUSH SOUTHEAST ACROSS
WESTERN KANSAS LATE TONIGHT. SHOWERS AND ISOLATED THUNDERSTORMS
WILL BE POSSIBLE ALONG AND BEHIND THE FRONT AS IT MOVES THROUGH
OVERNIGHT. MVFR CIGS/VSBYS MAY OCCUR IN ASSOCIATION WITH ANY
POTENTIAL STORMS. OTHERWISE, EXPECT VFR CONDITIONS TO
CONTINUE/REDEVELOP EARLY SUNDAY MORNING. LIGHT NORTHERLY
WINDS THIS EVENING WILL INCREASE UP TO AROUND 15 TO 25KT
LATE TONIGHT AS THE AFOREMENTIONED COLD FRONT PUSHES THROUGH
WESTERN KANSAS. THE WINDS WILL SUBSIDE SUNDAY MORNING AS
SURFACE HIGH PRESSURE BEGINS TO PUSH SOUTHEAST INTO THE
WESTERN HIGH PLAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 40 68 35 45 / 40 10 40 40
GCK 38 68 35 44 / 40 10 30 40
EHA 41 68 40 44 / 30 10 30 40
LBL 41 68 42 45 / 30 10 30 40
HYS 38 67 34 44 / 50 10 40 40
P28 47 69 40 46 / 40 10 50 50
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...RUSSELL
AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS TOPEKA KS
914 AM CDT FRI MAR 29 2013
.UPDATE...
ISSUED AT 901 AM CDT FRI MAR 29 2013
NO MAJOR UPDATES TO THE FORECAST. INTITIALIZED FORECAST GRIDS
WITH 900 AM OBSERVATIONS.
GARGAN
&&
.SHORT TERM AND LONG TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 414 AM CDT FRI MAR 29 2013
MOST RECENT SHORTWAVE TROUGH AT 08Z EXTENDING FROM IA INTO KS IS
MOVING SOUTHEAST AND WILL EXIT THE CWA EARLY THIS MORNING. THIS
WAVE IN CONJUNCTION WITH ISENTROPIC LIFT NORTH OF THE STATIONARY
BOUNDARY TO THE SOUTH HAS RESULTED IN NUMEROUS ELEVATED SHOWERS
AND THUNDERSTORMS PRIMARILY SOUTH OF I 70. AS THE WAVE AND LIFT
SHIFT SOUTHEAST AND MUCH DRIER AIR ALOFT OVERSPREADS THE
AREA...PRECIP CHANCES WILL DIMINISH BY SUNRISE LEAVING A DRY FCST
ACROSS THE COUNTY WARNING AREA FOR THE REMAINDER OF THE DAY.
CLOUDS WILL ALSO DECREASE OVER THE SOUTHERN AREA EARLY LEAVING
MOSTLY SUNNY SKIES MOST AREAS. HAVE THEREFORE BUMPED UP HIGHS FOR
TODAY INTO THE MIDDLE TO UPPER 60S ALL AREAS.
AS THE LLVL FLOW VEERS TONIGHT AND BECOMES MORE
SOUTH/SOUTHWESTERLY...MOISTURE WILL ONCE AGAIN SURGE BACK TO THE
NORTH...MAINLY FROM LATE EVENING THROUGH THE MORNING HOURS ON SATURDAY.
THE BETTER FOCUS FOR FORCING/CONVERGENCE AND ISENTROPIC LIFT WILL
OCCUR ACROSS PRIMARILY THE NORTHERN CWA AND HAVE MAINTAINED HIGHER
END CHANCE POPS IN THIS AREA...THEN DECREASED SOUTHWARD. AS THE NEXT
FRONT MOVES SOUTHEAST ACROSS THE CWA ON SATURDAY...THE AXIS OF
HIGHER CAPE/INSTABILITY WILL SET UP ACROSS THE SOUTHEAST PORTIONS OF
THE CWA IN THE AFTERNOON...PRIMARILY SOUTH AND EAST OF THE TURNPIKE.
IF INHIBITION IS ERODED...STRONG TO SEVERE THUNDERSTORMS WILL BE
POSSIBLE IN THIS AREA INTO THE EVENING HOURS BEFORE DECREASING AND
EXITING THE SOUTHEAST CORNER BY MIDNIGHT. UP TO QUARTER SIZE HAIL
AND STRONG GUSTY WINDS WOULD BE THE PRIMARY THREAT WITH THE
STRONGER CELLS.
SUNDAY IS STILL LOOKING DRY AHEAD OF THE NEXT...MUCH STRONGER COLD
FRONT ON MONDAY. A WEDGE OF WARM AIR WILL STILL RESIDE ACROSS THE
CWA OUT AHEAD OF THIS FRONT AND HAVE THEREFORE INCREASED SUNDAYS
HIGH TEMPS INTO THE MIDDLE TO UPPER 60S. AS THE FRONT THEN TRAVERSES
THE CWA FROM NORTH TO SOUTH...AT LEAST SCATTERED POST FRONTAL RAIN
SHOULD DEVELOP AND MAY MIX WITH AND/OR CHANGEOVER TO ALL SNOW LATE
SUNDAY NIGHT AND MONDAY BEFORE ENDING BY AFTERNOON. ANY SNOWFALL
ACCUMULATIONS AT THIS POINT APPEAR TO BE GENERALLY LESS THAN AN
INCH. EITHER WAY...MUCH COLDER CONDITIONS WITH HIGHS IN THE UPPER
30S TO LOW 40S ARE IN STORE FOR THE AREA ON MONDAY.
THE AREA SHOULD GRADUALLY TRANSITION FROM COOLER NORTHWEST FLOW ALOFT
TO A MORE ZONAL PATTERN THROUGH THE WEEK RESULTING IN MODERATING
TEMPERATURES. HIGHS SHOULD RISE INTO THE 50S BY WEDNESDAY...THEN THE
60S BY THURSDAY. WILL MAINTAIN A DRY FCST THROUGH THE REMAINDER OF
THE WEEK. 63
&&
.AVIATION...
11Z WATER VAPOR IMAGERY SHOWS THE WEAK UPPER WAVE BEGINNING TO PASS
TO THE EAST. WITH THE RAP AND NAM SHOWING ISENTROPIC LIFT
DIMINISHING...THINK ELEVATED SHOWERS WILL CONTINUE TO MOVE OFF TO
THE EAST. MODELS DO NOT SHOW THE MOISTURE ADVECTION AND ISENTROPIC
LIFT RETURNING UNTIL AFTER 02Z SAT. UNTIL THEN EXPECT VFR CONDITIONS
DUE TO A LACK OF STRONG FORCING AND THE BOUNDARY REMAINING TO THE
SOUTH AND WEST. UNCERTAINTY IN LOCATION OF PRECIP OVERNIGHT PRELUDES
ANY MENTION OTHER THAN A VCSH ONCE THE 850 WINDS VEER AROUND TO THE
SOUTHWEST AND BEGIN TO LIFT MOISTURE BACK INTO NORTHEAST KS LATE
THIS EVENING.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GARGAN
SHORT TERM...63
LONG TERM...63
AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1107 AM CDT FRI MAR 29 2013
.DISCUSSION...
SEE PREV DISCUSSION.
&&
.AVIATION...
11Z WATER VAPOR IMAGERY SHOWS THE WEAK UPPER WAVE BEGINNING TO PASS
TO THE EAST. WITH THE RAP AND NAM SHOWING ISENTROPIC LIFT
DIMINISHING...THINK ELEVATED SHOWERS WILL CONTINUE TO MOVE OFF TO
THE EAST. MODELS DO NOT SHOW THE MOISTURE ADVECTION AND ISENTROPIC
LIFT RETURNING UNTIL AFTER 02Z SAT. UNTIL THEN EXPECT VFR CONDITIONS
DUE TO A LACK OF STRONG FORCING AND THE BOUNDARY REMAINING TO THE
SOUTH AND WEST. UNCERTAINTY IN LOCATION OF PRECIP OVERNIGHT PRELUDES
ANY MENTION OTHER THAN A VCSH ONCE THE 850 WINDS VEER AROUND TO THE
SOUTHWEST AND BEGIN TO LIFT MOISTURE BACK INTO NORTHEAST KS LATE
THIS EVENING.
WOLTERS
&&
.PREV DISCUSSION... /414 AM CDT FRI MAR 29 2013/
MOST RECENT SHORTWAVE TROUGH AT 08Z EXTENDING FROM IA INTO KS IS
MOVING SOUTHEAST AND WILL EXIT THE CWA EARLY THIS MORNING. THIS WAVE
IN CONJUNCTION WITH ISENTROPIC LIFT NORTH OF THE STATIONARY BOUNDARY
TO THE SOUTH HAS RESULTED IN NUMEROUS ELEVATED SHOWERS AND
THUNDERSTORMS PRIMARILY SOUTH OF I 70. AS THE WAVE AND LIFT SHIFT
SOUTHEAST AND MUCH DRIER AIR ALOFT OVERSPREADS THE AREA...PRECIP
CHANCES WILL DIMINISH BY SUNRISE LEAVING A DRY FCST ACROSS THE
COUNTY WARNING AREA FOR THE REMAINDER OF THE DAY. CLOUDS WILL ALSO
DECREASE OVER THE SOUTHERN AREA EARLY LEAVING MOSTLY SUNNY SKIES
MOST AREAS. HAVE THEREFORE BUMPED UP HIGHS FOR TODAY INTO THE MIDDLE
TO UPPER 60S ALL AREAS.
AS THE LLVL FLOW VEERS TONIGHT AND BECOMES MORE
SOUTH/SOUTHWESTERLY...MOISTURE WILL ONCE AGAIN SURGE BACK TO THE
NORTH...MAINLY FROM LATE EVENING THROUGH THE MORNING HOURS ON
SATURDAY. THE BETTER FOCUS FOR FORCING/CONVERGENCE AND ISENTROPIC
LIFT WILL OCCUR ACROSS PRIMARILY THE NORTHERN CWA AND HAVE
MAINTAINED HIGHER END CHANCE POPS IN THIS AREA...THEN DECREASED
SOUTHWARD. AS THE NEXT FRONT MOVES SOUTHEAST ACROSS THE CWA ON
SATURDAY...THE AXIS OF HIGHER CAPE/INSTABILITY WILL SET UP ACROSS
THE SOUTHEAST PORTIONS OF THE CWA IN THE AFTERNOON...PRIMARILY SOUTH
AND EAST OF THE TURNPIKE. IF INHIBITION IS ERODED...STRONG TO SEVERE
THUNDERSTORMS WILL BE POSSIBLE IN THIS AREA INTO THE EVENING HOURS
BEFORE DECREASING AND EXITING THE SOUTHEAST CORNER BY MIDNIGHT. UP
TO QUARTER SIZE HAIL AND STRONG GUSTY WINDS WOULD BE THE PRIMARY
THREAT WITH THE STRONGER CELLS.
SUNDAY IS STILL LOOKING DRY AHEAD OF THE NEXT...MUCH STRONGER COLD
FRONT ON MONDAY. A WEDGE OF WARM AIR WILL STILL RESIDE ACROSS THE
CWA OUT AHEAD OF THIS FRONT AND HAVE THEREFORE INCREASED SUNDAYS
HIGH TEMPS INTO THE MIDDLE TO UPPER 60S. AS THE FRONT THEN TRAVERSES
THE CWA FROM NORTH TO SOUTH...AT LEAST SCATTERED POST FRONTAL RAIN
SHOULD DEVELOP AND MAY MIX WITH AND/OR CHANGEOVER TO ALL SNOW LATE
SUNDAY NIGHT AND MONDAY BEFORE ENDING BY AFTERNOON. ANY SNOWFALL
ACCUMULATIONS AT THIS POINT APPEAR TO BE GENERALLY LESS THAN AN
INCH. EITHER WAY...MUCH COLDER CONDITIONS WITH HIGHS IN THE UPPER
30S TO LOW 40S ARE IN STORE FOR THE AREA ON MONDAY.
THE AREA SHOULD GRADUALLY TRANSITION FROM COOLER NORTHWEST FLOW ALOFT
TO A MORE ZONAL PATTERN THROUGH THE WEEK RESULTING IN MODERATING
TEMPERATURES. HIGHS SHOULD RISE INTO THE 50S BY WEDNESDAY...THEN THE
60S BY THURSDAY. WILL MAINTAIN A DRY FCST THROUGH THE REMAINDER OF
THE WEEK. 63
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PADUCAH KY
405 AM CDT SUN MAR 31 2013
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 406 AM CDT SUN MAR 31 2013
CONSIDERED A DENSE FOG ADVISORY FOR WESTERN PORTIONS OF SOUTHEAST
MISSOURI DUE TO KPOF REPORTING 1/2 MILE OR LESS...BUT IT SEEMS TO
BE IMPROVING A BIT IN THE LAST HOUR AND WE HAVE LITTLE CLUE HOW
WIDESPREAD IT IS. WILL KEEP AN EYE ON IT...BUT FOR NOW WILL JUST
LET IT BE.
WEAK ECHOES FOR LIGHT RAIN HAVE JUST ABOUT PUSHED EAST OF THE
EVANSVILLE TRI STATE...BUT THERE MAY BE JUST A BIT LINGERING IN
THE KOWB AREA. THIS SHOULD COME TO AN END SHORTLY. OF GREATER
CONCERN IS THE AREA OF SHOWERS AND THUNDERSTORMS MOVING EAST
SOUTHEAST ACROSS EASTERN KANSAS AND WEST CENTRAL MISSOURI.
HAD TO LEAN ON THE HRRR MODEL SIMULATED REFLECTIVITY TO REPRESENT
THIS IN THE GRIDS. IN GENERAL WOULD EXPECT THE AREA TO WEAKEN AS
IT MOVES INTO OUR REGION JUST AFTER SUNRISE...SO WILL HAVE 20-30
POPS FOR NOW...GENERALLY SWEEPING ACROSS OUR SOUTHWEST HALF 14Z-
20Z. THIS WEAKENING TREND IS SUPPORTED BY THE 06Z NAM...WHICH
KEEPS ANY INSTABILITY TO OUR WEST AND SOUTHWEST. WILL HAVE TO KEEP
A CLOSE EYE ON THIS SITUATION AS WELL AND BE PREPARED TO UPDATE
IF/WHEN IT BECOMES NECESSARY.
TEMPERATURES EARLY THIS MORNING ARE NEARLY STEADY...SO WE WILL
HAVE A MILD START TO THE DAY...WHICH IS GOOD BECAUSE THE LOW
CLOUDS/FOG AND EVENTUALLY SOME SHOWERS WILL DELAY WARMING THROUGH
THE MORNING. TRIED TO CAPTURE THIS TREND IN THE TEMPERATURE
GRIDS...BUT WE SHOULD JUMP UP WELL INTO THE 60S WITH SOME SUNSHINE
THIS AFTERNOON. STAYED CLOSE TO CONSENSUS.
LIKE THE 00Z AND 06Z NAM WITH THE REAL COLD FRONT/SURFACE HIGH
SURGE THROUGH THE AREA LATE TONIGHT AND MONDAY...AS IT SHOULD
HANDLE THE SHALLOW COLD AIRMASS BETTER THAN THE LESSER RESOLVED
GFS. THE NAM DOES GENERATE SOME VERY MEAGER QPF OVER THE
EVANSVILLE TRI STATE TONIGHT WITH THE INITIAL WIND SHIFT...BUT THE
GFS IS DRY. DECIDED TO MENTION SOME SPRINKLES IN THAT AREA THROUGH
THE NIGHT...BUT DID NOT INTRODUCE A MEASURABLE POP. CONSENSUS OF
GUIDANCE SEEMS TO HAVE A GOOD HANDLE ON TEMPERATURES TONIGHT.
TEMPERATURES ONLY FALL INTO THE UPPER 30S IN THE NORTH...SO LITTLE
CHANCE OF FLURRIES WITH THE SPRINKLES TONIGHT.
FOR MONDAY...THE MODELS CONTINUE TO TREND DRIER AND DRIER FOR OUR
AREA. SIMILAR TO TONIGHT...DECIDED TO JUST PLASTER A CHANCE OF
SPRINKLES ACROSS THE ENTIRE AREA THROUGH THE DAY...IN LIEU OF A
VERY SMALL MEASURABLE POP. TEMPERATURES WILL SUPPORT ALL LIQUID
THROUGH THE DAY. FIGURE WITH THE SURGE CONSISTENTLY ADVERTISED IN
THE NAM RUNS...THAT TEMPERATURES WILL BE COOLER THAN MOST GUIDANCE
INDICATES. STAYED ON THE LOW SIDE OF GUIDANCE CLOSER TO THE
NAM/MET...BUT THAT MAY NOT BE COOL ENOUGH.
MONDAY NIGHT WILL BE DRY...BUT WE WILL REMAIN IN CYCLONIC WEST
NORTHWEST FLOW ALOFT...SO CANNOT RULE OUT SOME LIGHT
PRECIPITATION...ESPECIALLY OVER OUR SOUTHWEST MONDAY NIGHT INTO
TUESDAY. THE GFS IS THE MOST AGGRESSIVE IN GENERATING LIGHT QPF
WITH SOME FRONTOGENETIC FORCING IN THE 850-700MB LAYER IN THE FAR
SOUTHWEST. INTRODUCED SOME VERY SMALL POPS NEAR THE ARKANSAS
BORDER AND THE BOOT HEEL REGION JUST TO BE SAFE. LATELY...IF THERE
IS ANY CHANCE OF US GETTING WET IT SEEMS TO HAPPEN. TEMPERATURES
IN THAT AREA SHOULD BE NO LOWER THAN THE MIDDLE 30S...SO KEPT THIS
ALL RAIN AS WELL. CONSENSUS TEMPERATURES LOOKED FINE MONDAY NIGHT
AND TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 406 AM CDT SUN MAR 31 2013
THIS EXTENDED PERIOD FOR THIS FORECAST ISSUANCE WILL SERVE AS THE
TRANSITION OF EXTREMES IN TEMPERATURE FROM NEAR RECORD LOWS
WEDNESDAY MORNING TO ABOVE NORMAL /MIDDLE 60S/ HIGHS NEXT WEEKEND.
GIVEN THE BELOW NORMAL TEMPERATURES WE HAVE BEEN EXPERIENCING IN
MARCH...TEMPERATURES AT OR ABOVE NORMAL WILL BE A WELCOME CHANGE.
THE ONLY WEATHER MAKER OF CONSEQUENCE WILL OCCUR THURSDAY/THURSDAY
NIGHT. ANY MEASURABLE POPS AND WEATHER /GENERALLY SLIGHT IN
CATEGORY/ WILL BE LIMITED TO WEST KENTUCKY AND A SMALL PART OF THE
SOUTHEAST MISSOURI BOOTHILL. THE SOURCE REGION FOR THIS SYSTEM IS
THE CLOSED LOW CURRENTLY OFF THE CALIFORNIA COAST. THIS FEATURE IS
EXPECTED TO PUSH TOWARD THE CENTRAL ROCKIES AND DIVE EAST-SOUTHEAST
INTO THE LOWER MISSISSIPPI VALLEY. DURING THE PAST 3-4 DAYS...THE
NORTHERN EDGE OF THIS CLOSED LOW/WAVE HAS BEEN FORECAST BY THE
GFS/ECMWF/GEM GUIDANCE TO SKIRT ALONG THE SOUTHERN BORDER OF THE WFO
PAH FORECAST AREA. THERE HAS BEEN ENOUGH MODEL RUNS TO STILL
INDICATE THAT VERY FEW LOCATIONS WILL SEE ANY RAIN...IF ANY...ON
THURSDAY. THE MAIN IMPACT WILL BE CLOUD COVER...WITH A SHARP
DEMARCATION LINE ON THE NORTHERN EDGE OF THE DEFORMATION ZONE
ASSOCIATED WITH THE LOW/WAVE. NORTHEAST WINDS DURING THIS TIME
PERIOD MAY TEMPER HIGHS SOMEWHAT.
WITH HIGH PRESSURE DOMINATING THE REGION THROUGH MOST OF THE
PERIOD...CLOUD COVER WILL BE MINIMAL OUTSIDE OF THE DISTURBANCE ON
THURSDAY. THIS WILL SET THE STAGE FOR GOOD INSOLATION/DRY AIR
ADVECTION AND EVAPORATION. A MANUAL UPWARD ADJUSTMENT WAS MADE TO
THE MAX TEMPERATURES FROM FRIDAY THROUGH SUNDAY TO ACCOUNT FOR A
LARGER DIURNAL RANGE /25-27 DEGREES F/IN TEMPERATURES WITH THE DRIER
AIR IN PLACE ACROSS THE WFO PAH FORECAST AREA.
AS A SIDE NOTE...MIN FORECAST TEMPERATURES WEDNESDAY MORNING LOOK
LIKE THEY MAY BE ONE TO TWO DEGREES HIGHER THAN THE RECORD
TEMPERATURES ON THE BOOKS. SUBTLE MICRO-CLIMATE CHANGES AROUND THE
OBSERVATION SITES WILL DETERMINE WHETHER ANY RECORDS ARE TIED OR SET
WEDNESDAY MORNING.
&&
.AVIATION...
ISSUED AT 1223 AM CDT SUN MAR 31 2013
RAIN WILL CONTINUE TO SHIFT EAST OF THE REGION OVERNIGHT. LEFTOVER
LOW LEVEL MOISTURE WILL RESULT IN IFR CONDITIONS DUE TO BOTH FOG AND
LOW CLOUDS. THE GREATEST POTENTIAL FOR DENSE FOG APPEARS TO BE WEST
OF THE MISSISSIPPI RIVER. THE FOG AND LOW CLOUDS WILL GRADUALLY
CLEAR OUT SUNDAY MORNING...LEAVING BEHIND VFR CONDITIONS BY
AFTERNOON. LIGHT AND VARIABLE WINDS TONIGHT WILL BECOME W/NW 5 TO 10
KNOTS SUNDAY.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...DRS
LONG TERM...SMITH
AVIATION...RJP
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
136 AM EDT SUN MAR 31 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 453 PM EDT SAT MAR 30 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A RIDGE OVER THE FAR WRN
CONUS INTO WRN CANADA WHILE DOWNSTREAM TROF WAS AMPLIFYING S THRU
CNTRL CANADA INTO THE NCNTRL CONUS. WITHIN THE DEEPENING TROF...A
SHORTWAVE MOVING ACROSS THE UPPER GREAT LAKES HAS BROUGHT A BAND OF
PCPN TO UPPER MI TODAY. PCPN WAS MAINLY RAIN OVER THE W...BUT MIXED
WITH/CHANGED TO SNOW OVER THE CNTRL/E. SNOW WAS MDT/HVY ACROSS
IRON/DICKINSON COUNTIES WHERE A FEW INCHES OF WET SNOW ACCUMULATION
HAS BEEN REPORTED. THE HEAVIER SNOW IS NOW STREAKING E TOWARD LUCE
COUNTY. BACKEDGE OF THE MAIN PCPN AREA WAS OVER CNTRL UPPER MI AS OF
20Z. WITH DEPARTURE OF THIS AREA OF PCPN...ATTENTION IN THE SHORT
TERM SHIFTS TO SHORTWAVE DIGGING SHARPLY INTO THE UPPER GREAT LAKES
LATE TONIGHT/SUN AND THE INCREASINGLY COLDER AIR IT WILL BRING.
INCORPORATING EXTRAPOLATION FOR ENDING PCPN...EXPECT STEADIER PCPN
TO EXIT THE ERN FCST AREA AROUND 03Z WITH ALL OF THE AREA DRY BY
06Z. MAY SEE AN INCH OR SO OF WET SNOW OVER THE INTERIOR E DURING
THE LATE AFTN. LOW CLOUDS AND FOG WERE PRESENT EARLY TODAY BEHIND
THE PCPN AREA IN MN...AND WILL PROBABLY SEE SOME OF THAT AND PERHAPS
SOME -DZ IN MAINLY AREAS THAT SEE UPSLOPING WITH A W WIND FOR A FEW
HRS AFTER PCPN ENDS AND BEFORE THE ONSET OF CAA OVERNIGHT INCREASES
LOW-LEVEL MIXING. BY 12Z...850MB TEMPS ARE PROGGED AT -8/-9C OVER
WRN LAKE SUPERIOR. WHILE THAT IS SHY OF THE THRESHOLD FOR LES GIVEN
WATER TEMPS AROUND 1C...SRN EDGE OF DEEP LAYER FORCING ASSOCIATED
WITH APPROACHING SHORTWAVE AND PRESENCE OF CYCLONIC FLOW MAY
GENERATE SOME LAKE ENHANCED -SHSN OVER NW UPPER MI LATE IN THE
NIGHT.
DURING THE DAY SUN...SHORTWAVE DIGS S ACROSS THE UPPER GREAT
LAKES...BRINGING 100-120M HEIGHT FALLS AT 500MB. ALTHOUGH BEST DEEP
LAYER FORCING PASSES N AND NE OF UPPER MI...DEEP CYCLONIC FLOW AND
SUFFICIENT INCREASE IN MOISTURE DEPTH TO AROUND 10KFT SUGGESTS SCT
TO NMRS -SHSN ARE A GOOD BET. LATE MAR SOLAR INSOLATION WILL ADD A
DIURNAL COMPONENT TO -SHSN COVERAGE OVER THE INTERIOR WHILE
DISRUPTING NORMAL LAKE EFFECT PROCESSES THAT WOULD BE GETTING
UNDERWAY OVER LAKE SUPERIOR AS 850MB TEMPS FALL TOWARD -14C IN THE
AFTN. ALTHOUGH COLUMN BECOMES MORE SUPPORTIVE OF SNOW AS PTYPE AS
THE DAY PROGRESSES...DAYTIME HEATING SHOULD RESULT IN MIX WITH -SHRA
INTO THE MID AFTN OVER THE SCNTRL. WINDS MAY APPROACH ADVY CRITERIA
OVER THE KEWEENAW...BUT WITH MIXED LAYER WINDS LOW/MID 30KT AT MOST
AND ONLY MODEST PRES RISES APPROACHING FROM THE NW...DO NOT
ANTICIPATE WIND ADVY BEING NEEDED AT THIS POINT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 453 PM EDT SAT MAR 30 2013
CONTINUE TO SEE GOOD AGREEMENT FROM GFS/ECMWF/GEM-NH IN OVERALL
LARGER SCALE PATTERN FOR THE LONG TERM. DEEP AND COLD TROUGHING
INITIALLY IN PLACE LEADS TO A PERIOD OF LAKE ENHANCED SNOW FOR
SNOWBELTS FAVORED BY NORTHWEST WINDS SUNDAY NIGHT THROUGH TUESDAY
MORNING. FOCUSED IN ON MORE OF THE DETAILS THIS GO AROUND. WAVE
THAT MOVES THROUGH TO BRING IN THE TROUGHING ON SUNDAY NIGHT PRETTY
SHARP UPSTREAM THIS MORNING OVER NORTHERN MANITOBA INTO NINAVUT.
WENT WITH MODELS THAT WERE SHARPER WITH H5 WAVE AND RESULTING SFC
TROUGH DROPPING ACROSS LK SUPERIOR LATE SUNDAY AFTN INTO SUNDAY
EVENING. SOUNDINGS DURING THAT TIME INDICATE MORE OF A WIDESPREAD
SNOW JUST IN WAKE OF FRONT...ALONG WITH PUSH OF NORTH WINDS TO AROUND
40 MPH. EXPANDED POPS OVER MUCH OF THE NORTH HALF OF CWA SUNDAY
EVENING. SNOWFALL RATES MAY EXCEED 1"/HOUR FOR A COUPLE HOURS AS
THIS BAND OF SNOW MOVES THROUGH. BY MIDNIGHT...MODELS INDICATE
WIDESPREAD DEEPER H8-H7 MOISTURE DEPARTS LEAVING MOST OF THE SNOW
SET UP OVER HIGHER TERRAIN OF WEST AND NCNTRL CWA AND ALSO FOR
SNOWBELTS FROM MUNISING TO NEWBERRY.
LAKE ENHANCED SNOW THAT OCCURS FOR THOSE SNOWBELTS LATER SUNDAY
NIGHT INTO MONDAY MAY BE HEAVY AT TIMES AS SOUNDINGS INDICATE
MOISTURE THROUGH H8 AND INVERSION HEIGHTS UP TO 10KFT. OVER-WATER
INSTABILITY IS SUFFICIENT AS H85 TEMPS ARE AROUND -16C. AT FIRST
GLANCE SEEMS LIKE LAKE EFFECT SNOW WATCH MAY BE IN ORDER. THERE ARE
A COUPLE NEGATIVE FACTORS THOUGH THAT PROHIBITED ISSUANCE OF WATCH.
FIRST OF WHICH IS DRYING NOTED BLO 5KFT LEADING TO MORE OF AN
INVERTED-V LOOK TO SOUNDING...ESPECIALLY OVERNIGHT SUNDAY NIGHT INTO
MONDAY. SECOND NEGATIVE IS SHEAR IN THE MOIST CONVECTIVE LAYER AT
LEAST TO START OUT...BUT THIS DOES EASE LATE SUNDAY NIGHT THOUGH BLYR
WINDS STAY UP TO 30 KTS FROM THE NORTHWEST. BEST SHOT AT HEAVIER SNOW
WOULD BE THROUGH MID-LATE MORNING ON MONDAY AS DAYTIME HEATING/HIGHER
SUN ANGLE WILL ACT TO DISRUPT SNOW SHOWERS AS THE DAY GOES ON. LAKE
EFFECT SNOW SHOWERS MAY INCREASE AGAIN MONDAY NIGHT. DUE TO COMBO OF
THE LAKE EFFECT SNOWS AND BLOWING SNOW...LIKELY WILL NEED ADVISORY
HEADLINES INTO MONDAY NIGHT AND TUESDAY MORNING.
SINCE THERE IS NOT MUCH BLOCKINESS DOWNSTREAM...DEEP TROUGH WILL REMAIN
PROGRESSIVE WITH RISING HEIGHTS DEVELOPING OVER UPPER LAKES AS EARLY
AS TUESDAY. SUFFICIENTLY COLD AND MOIST ENOUGH FOR LK EFFECT BUT
LARGER SCALE NEGATIVES SHOULD RESULT IN DIMINISHING TREND TO LK
EFFECT BY TUESDAY AFTN. POPS REFLECTED THIS FOR MOST PART...JUST
NEEDED SOME MINOR TWEAKS.
AFTER PARTIAL CLEARING AND WARMER CONDITIONS FOR WEDNESDAY ANOTHER
SHORTWAVE TROUGH THEN SWINGS ACROSS MANITOBA AND NORTHERN ONTARIO
WEDNESDAY NIGHT AND THURSDAY. ASSOCIATED COLD FRONT MOVES ACROSS
UPPER LAKES ON THURSDAY. DPROG/DT FROM EARLIER GFS/ECMWF RUNS
INDICATED A SLOWER TREND WITH SHORTWAVE POINTING TO MOST OF
PRECIPITATION FROM THE SYSTEM TAKING PLACE ON THURSDAY OVER UPPER
MICHIGAN. 12Z GFS REALLY SPED UP AND SEEMS OUT OF PLACE NOW WITH
PCPN TIMING. 1000-500MB AND 1000-850MB THICKNESSES INDICATE MIX OF
RAIN/SNOW. LIMITED MOISTURE WILL KEEP AMOUNTS LIGHT. COOLER AND DRY
IN WAKE OF COLD FRONT INTO FRIDAY.
QUESTIONS INCREASE FOR NEXT WEEKEND. GOOD BET THAT UPPER LAKES WILL
BE ON THE SOUTHERN EDGE OF STRONGER JET STREAM RIDING ALONG SOUTHERN
TIER OF CANADA. AS MID-LEVEL FLOW BECOMES MORE WESTERLY MODELS
INDICATE SHORTWAVE TROUGH AND SFC-H85 LOWS VCNTY OF NORTHERN PLAINS
INTO WESTERN GREAT LAKES BY 12Z SATURDAY. POOR CONSISTENCY ON WHERE
SFC-H85 LOWS SET UP THOUGH. LATEST ECMWF/GFS CONTINUE TO INDICATE
FARTHER NORTH LOW WITH QPF INTO UPPER LAKES BY NEXT SATURDAY WHILE
EARLIER RUNS KEPT MOST OF QPF TO SOUTH. 1000-500MB AND 1000-850MB
THICKNESSES AT OR ABOVE 540DAM AND 1305M AND H85 TEMPS OVER 0C INTO
WESTERN CWA INDICATE MIX OF RAIN AND SNOW. CONSENSUS OF MODELS CAME
UP WITH HIGHER CHANCE POPS WHICH WILL WORK IF THE NORTHERN TREND
CONTINUES IN THE MODELS. JUST CANNOT SEEM TO SHAKE THIS COOLER AND
ACTIVE WEATHER PATTERN AS WE HEAD INTO THE FIRST WEEK OF APRIL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 134 AM EDT SUN MAR 31 2013
ARRIVAL OF DRIER AIR SHOWN ON THE 00Z INL RAOB WILL RESULT IN VFR
CONDITIONS EARLY THIS MRNG AT CMX/IWD AND A BREAKUP OF THE
FOG/ST/IFR CONDITIONS NOW IMPACTING SAW BY 09Z. EXPECT INCREASING
POTENTIAL OF -SHSN AT WRN TAF SITES BY LATE MRNG AS CONDITIONS FALL
TO MVFR AT CMX/IWD WITH ARRIVAL OF NEXT DISTURBANCE. GUSTY WNW WINDS
WILL DEVELOP FOLLOWING NEXT SFC TROF PASSAGE LATE THIS MORNING. WNW
AND COLD ADVECTION BEHIND FRONT WILL BRING A CHANCE OF -SHSN SUNDAY
AFTERNOON AT KSAW ALONG WITH MVFR CIGS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 453 PM EDT SAT MAR 30 2013
STRONGER DISTURBANCE MOVING INTO THE UPPER LAKES SUN WILL USHER
COLDER AIR OVER LAKE SUPERIOR WHILE SFC LOW PRES DEEPENS TO THE E
AND NE. THIS WILL RESULT IN STRENGTHENING NW WINDS ACROSS THE LAKE.
IN FACT...NW GALES ARE EXPECTED TO DEVELOP OVER CNTRL AND ERN LAKE
SUPERIOR SUN AFTN. UNDER SLOW MOVING WEATHER PATTERN WITH COLD
UNSTABLE AIR OVER THE LAKE...THE GALES WILL LIKELY CONTINUE INTO
TUE. FREEZING SPRAY WILL ALSO DEVELOP SUN NIGHT AND LINGER INTO TUE
AS UNSEASONABLY COLD AIR SETTLES OVER THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 2 PM THIS AFTERNOON TO 8 PM EDT TUESDAY FOR
LSZ264>267.
GALE WARNING FROM 2 PM THIS AFTERNOON TO 6 PM EDT MONDAY FOR
LSZ244-245-249>251.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...KC
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
225 AM CDT SUN MAR 31 2013
.SHORT TERM...(EASTER SUNDAY)
ISSUED AT 224 AM CDT SUN MAR 31 2013
FORECAST HAS CHANGED TODAY GIVEN CURRENT CONDITIONS AND LATEST SHORT
RANGE MODEL GUIDANCE. SHORTWAVE ENERGY...EVIDENT ON LATEST WATER
VAPOR IMAGERY...DROPPING SOUTHEAST FROM SOUTHERN NEBRASKA HAS LED TO
A LARGE AREA OF SHOWERS AND SOME THUNDERSTORMS DEVELOPING ACROSS
EASTERN KANSAS AND WEST CENTRAL MISSOURI.
LATEST RUC AND HRRR SHOW THIS AREA OF RAIN SHOWERS/STORMS EXPANDING
AS EAST/SOUTHEAST THIS MORNING ACROSS CENTRAL MISSOURI AND THE
OZARKS...PERHAPS GRAZING EAST CENTRAL MISSOURI AND SOUTHWEST
ILLINOIS. WILL FINE TUNE POPS BEFORE FORECAST ISSUANCE BASED ON THE
VERY LATEST RADAR TRENDS.
THERE WILL OBVIOUSLY BE A SLOWER CLEARING TREND TO THE CLOUDS THANKS
TO THIS SHORTWAVE...AND FEEL IT PRUDENT TO SIDE WITH SLIGHTLY COOLER
MAV GUIDANCE FOR HIGH TEMPERATURES.
TO COMPLICATE THE FORECAST EVEN FURTHER...MUCH OF THE EXPLICIT AND
HIGH RESOLUTION MODEL GUIDANCE DEPICT SOME ISOLATED SHOWERS
DEVELOPING ALONG A PREFRONTAL TROF THIS AFTERNOON AND EVENING FROM
CENTRAL ILLINOIS TOWARD THE ST. LOUIS METRO AREA. SO HAVE INCLUDED
SOME LOW CHANCE/ISOLATED POPS FOR THIS AS WELL.
CVKING
&&
.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 224 AM CDT SUN MAR 31 2013
(TONIGHT AND MONDAY)
ARCTIC COLD FRONT EXPECTED TO MOVE SOUTH ACROSS THE CWA TONIGHT
WITH NORTH WIND AND COLD ADVECTION TAKING CONTROL OF THE WEATHER
FOR THE EARLY PART OF THE WORK WEEK. LATEST GUIDANCE CONTINUES TO
DEPICT A BAND OF LIGHT POST FRONTAL PRECIPITATION AFFECTING MAINLY
NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS SUNDAY NIGHT. THIS
PRECIPITATION SHOULD WEAKEN AS IT PROGRESSES SOUTH MONDAY MORNING
TO THE I-70 CORRIDOR. MAINTAINED RAIN/SNOW MIX...BUT DONT EXPECT
ANY ACCUMULATION DUE TO WARM AIR AND GROUND TEMPERATURES. HAVE
SIDED WITH COOLER MET GUIDANCE FOR TEMPERATURES.
(TUESDAY THROUGH SATURDAY)
SLOW WARMING TREND EXPECTED WITH HIGH PRESSURE MOVING EAST OF THE
AREA BY LATE IN THE WEEK. HAVE KEPT FORECAST DRY AS GUIDANCE KEEPS
CUTOFF LOW TO THE SOUTH OF THE AREA THURSDAY.
CVKING
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 619 PM CDT SAT MAR 30 2013
COMPLEX WX FORECAST THRU THE NEXT 6 TO 12 HRS. RA WILL CONTINUE TO
MOVE EWD AND SHUD BE AFFECTING ONLY KCPS BY THE TIME TAFS ARE
VALID. CONDITIONS SHUD IMPROVE BRIEFLY BEHIND THE PRECIP...BUT
SHUD FALL BACK INTO THE MVFR RANGE QUICKLY. LARGER FORECAST ISSUE
FOR TONIGHT IS IF FG/ST WILL DEVELOP LATER TONIGHT. ATTM...KCOU
HAS THE BEST POTENTIAL FOR IFR FG/ST DEVELOPING AND HAVE TRENDED
TAF IN THAT DIRECTION. TOO MANY QUESTIONS REMAIN TO CHANGE THE
FORECAST DRASTICALLY NOW. OTHERWISE...CONDITIONS SHUD IMPROVE
QUICKLY SUN MORNING AS THE FNT DRIFTS S OF THE TERMINALS. WITH
DEEP MIXING...HIGH BASED CU SHUD FORM DURING THE AFTERNOON HOURS
AND MAY EVEN GENERATE PRECIP AFFECTING KUIN/KSUS/KCPS IN THE MID
TO LATE AFTERNOON.
SPECIFICS FOR KSTL...BULK OF PRECIP SHUD BE E OF THE TERMINAL BY
00Z WITH ONLY LIGHT PRECIP LINGERING. STILL SOME QUESTION
REGARDING FG/ST DEVELOPMENT TONIGHT AND MADE ONLY MINOR CHANGES TO
THE PREV TAF. CONDITIONS SHUD IMPROVE QUICKLY SUN MORNING AS THE
FNT MOVES S OF THE TERMINAL. EXPECT HIGH BASED CU TO DEVELOP AND
POSSIBLY A BRIEF SHRA SUN MID TO LATE AFTERNOON.
TILLY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BUFFALO NY
319 AM EDT SUN MAR 31 2013
.SYNOPSIS...
SOUTHERLY WINDS WILL BRING A MILD DAY TODAY BEFORE A COLD FRONT
APPROACHES WITH SHOWERS DEVELOPING DURING THE AFTERNOON. THE COLD
FRONT WILL USHER IN MUCH COLDER TEMPERATURES FOR THE FIRST HALF OF
NEXT WEEK ALONG WITH SCATTERED SNOW SHOWERS AND HEAVIER LAKE EFFECT
SNOW EAST OF THE LAKES.
&&
.NEAR TERM /THROUGH TONIGHT/...
LEAD SHORTWAVE CURRENTLY LIFTING INTO THE OHIO VALLEY. ASSOCIATED
SHOWER ACTIVITY SHOWING UP ON UPSTREAM REGIONAL RADARS ACROSS
WESTERN OHIO. THIS ACTIVITY IS IN DECENT AGREEMENT WITH LATEST
HIGHER RESOLUTION HRRR RUN WHICH BRINGS THE LEADING EDGE OF SHOWERS
ASSOCIATED WITH THIS SHORTWAVE INTO THE SOUTHERN TIER AND WESTERN
FINGER LAKES BETWEEN 10 AM AND 2 PM.
MODELS CONTINUING TO AGREE UPON THE SPLIT IN PRECIPITATION PATTERN
BETWEEN THE SOUTHERN AREA OF PRECIPITATION ASSOCIATED WITH THE
SHORTWAVE WORKING THROUGH THE OHIO VALLEY... AND THE NORTHERN STREAM
SYSTEM WHICH LAGS BEHIND BY SEVERAL HOURS. THE NORTHERN SYSTEM WILL
GENERATE ADDITIONAL WIDESPREAD SHOWER ACTIVITY BY EARLY TO MID
AFTERNOON AS THE ASSOCIATED COLD FRONT APPROACHES THE REGION. SPC
SREF PARAMETERS KEEP PRIMARY INSTABILITY AXIS WELL SOUTH OF THE
AREA...THEREFORE NO NEED TO INCLUDE MENTION OF THUNDER IN THE
FORECAST.
AHEAD OF THE FRONT AND BEFORE THE RAIN ARRIVES...THE SOUTHERLY
DOWNSLOPE FLOW COMBINED WITH WARMER TEMPERATURES ALOFT WILL ALLOW
THE LAKE PLAINS TO WARM WELL INTO THE 50S. THE HIGHER TERRAIN OF THE
INTERIOR SOUTHERN TIER AND EAST OF LAKE ONTARIO WILL TOP OUT IN THE
MID TO UPPER 40S WITHOUT THE BENEFIT OF DOWNSLOPE FLOW AND AN
EARLIER START TO THE RAIN.
THE COLD FRONT WILL BE PUSH THROUGH EARLY TONIGHT. THE COLD AIR
ADVECTION IS QUITE IMPRESSIVE BEHIND THE FRONT AND WE SHOULD SEE A
CHANGE OVER TO SNOW OR A MIX BRIEFLY BEFORE THE PRECIPITATION
DIMINISHES OVERNIGHT. WIND SHOULD PICK UP IN THE STRONG COLD AIR
ADVECTIVE PATTERN...BUT SHOULD BE LIMITED TO GUSTS TO NEAR 30 MPH.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AN ARCTIC FRONT WILL CROSS THE REGION MONDAY MORNING WITH A
CHANGEOVER FROM RAIN TO SNOW SHOWERS. 850MB TEMPS AT 12Z MONDAY WILL
RANGE -12C AT THE NIAGARA RIVER TO -4C ACROSS CENTRAL NY...FALLING
TO -12C TO -13C BY 00Z TUESDAY. THESE BOUNDARY LAYER TEMPS WILL BE
SUFFICIENTLY COLD TO SUPPORT SOME LAKE EFFECT RESPONSE...BUT THE
DESTABILIZING EFFECT OF EARLY APRIL SUNSHINE WILL DISRUPT ANY
CONCENTRATED PRECIP...WILL HAVE LIKELY POPS FOR SMALL ACCUMULATIONS
BUT DO NOT EXPECT ANY SIGNIFICANT ACCUMS UNTIL OVERNIGHT MONDAY
NIGHT TO TUESDAY MORNING. WELL ALIGNED WESTERLY WINDS WILL FOCUS THE
LAKE SNOW ON THE HIGHER TERRAIN OF THE WESTERN SOUTHERN TIER AND ON
THE TOP OF THE TUG HILL PLATEAU EAST OF LAKE ONTARIO. THE LONGER
FETCH ALONG THE LENGTH OF LAKE ONTARIO WILL ALLOW THE TUG HILL TO
APPRECIATE A BETTER CHANCE FOR SIGNIFICANT SNOW ACCUMULATION MONDAY
NIGHT THROUGH EARLY WEDNESDAY. BOTH 00Z GFS AND ECMWF SHOW A WEAK
SHORT WAVE CROSSING THE EASTERN GREAT LAKES ON WEDNESDAY WITH ONLY
CHANCE POPS ASSOCIATED...LIMITING FACTORS AS THE LACK OF DEEP
MOISTURE AND SURFACE HIGH PRESSURE STARTING TO BUILD IN FROM THE
WEST.
IT IS POSSIBLE THAT THIS LAKE EFFECT EVENT FROM MONDAY NIGHT TO
WEDNESDAY MORNING MAY BRING WARNING CRITERIA SNOWS AS SUGGESTED BY
RECENT CIPS ANALOGS OF THE TOP 15 MOST SIMILAR EVENTS. ACCUMULATIONS
OF 6 TO 12 INCHES OR MORE MAY BE POSSIBLE UNDER THE MOST PERSISTENT
BANDS. THE DURATION OF THE EVENT WILL LIKELY LEAD TO THE HIGHER
ACCUMULATIONS...EVEN WITH THE LIMITING FACTOR OF LESS THAN OPTIMAL
MOISTURE PROFILE AND THE DISRUPTIVE INSOLATION EFFECTS DURING THE
DAYTIME. WILL CONTINUE TO HIGHLIGHT THIS EVENT IN THE HWO...BUT WILL
HOLD OFF FOR ANOTHER MODEL RUN TO ASSESS THE POSSIBILITY OF A LAKE
SNOW WATCH.
TEMPERATURES WILL REMAIN WELL BELOW NORMAL THROUGH MONDAY AND
TUESDAY. THE COLD AIR ADVECTION WILL KEEP HIGHS LIMITED TO THE LOW
AND MID 30S...AND ONLY UPPER 20S OVER THE HIGHER TERRAIN OF THE
WESTERN SOUTHERN TIER AND TUG HILL ON TUESDAY. OVERNIGHT LOWS WILL
BE IN THE 20S MONDAY AND TUESDAY NIGHTS. WEDNESDAY WILL HAVE A
SLIGHT RISE IN TEMPS WITH HIGHS IN THE 30S ACROSS THE REGION AND
BACK TO 20S WEDNESDAY NIGHT.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
NOW HERE IS THE GOOD NEWS...WE BEGIN TO SEE TEMPERATURES MODERATING
BACK TO NORMAL THROUGH NEXT WEEKEND.
WE WILL SEE SOME BRIEF RIDGING ON THURSDAY BRINGING A SUNNY DAY WITH
WARMER TEMPS RISING INTO THE UPPER 40S. SIMILAR CONDITIONS TO WHAT
WE SAW THIS FINE SATURDAY AFTERNOON. THE FORECAST BECOMES A BIT
DIFFICULT ON FRIDAY WHERE BOTH GFS AND EC MODELS PHASE THE TWO
SHORTWAVES TOGETHER ALONG THE EAST COAST WITH DEEP SURFACE
CYCLOGENESIS OCCURRING. THERE ARE SOME DIFFERENCES IN TIMING AND
LOCATION OF THE FORMATION OF A STRONG SURFACE LOW BUT GENERALLY THE
MODELS LIFT IT FROM THE CAROLINA COAST NORTH TOWARD NEW ENGLAND BY
FRIDAY NIGHT. ANOTHER WEAKER SYSTEM WILL DRIFT ACROSS EASTERN
CANADA. THERE IS POTENTIAL FOR EITHER SYSTEM TO CLIP OUR FORECAST
AREA SO WILL GO WITH LOW CHANGE FOR SHOWERS AT THIS TIME.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
MID AND HIGH LEVEL CLOUDS WILL CONTINUE TO INCREASE OVERNIGHT AS
MOISTURE ASSOCIATED WITH THE APPROACHING MIDWEST FRONT MOVES SLOWLY
TO THE EAST. A FEW SHOWERS MAY DEVELOP LATE SUNDAY MORNING ACROSS
THE FINGER LAKES AND CENTRAL NEW YORK...AND THEN SPREAD INTO THE
EASTERN LAKE ONTARIO REGION BY EARLY AFTERNOON WITH LOCAL MVFR
CONDITIONS. IT APPEARS THIS FIRST BATCH OF SHOWERS WILL REMAIN JUST
EAST OF THE TAF SITES.
LATER SUNDAY AFTERNOON PERIODS OF RAIN WILL BECOME MORE WIDESPREAD
ACROSS THE REGION AND LAST THROUGH SUNDAY EVENING BEFORE TAPERING
OFF FROM WEST TO EAST. THIS WILL PRODUCE AREAS OF MVFR...WITH IFR
ACROSS THE HIGHER TERRAIN.
OUTLOOK...
MONDAY...VFR/MVFR WITH A FEW SNOW SHOWERS LIKELY.
MONDAY NIGHT THROUGH TUESDAY NIGHT...VFR/MVFR WITH A CHANCE OF SNOW
SHOWERS...EXCEPT IFR IN LAKE EFFECT SNOW EAST OF THE LAKES.
WEDNESDAY...VFR/MVFR WITH A CHANCE OF SNOW SHOWERS.
THURSDAY...VFR.
&&
.MARINE...
SOUTHERLY WINDS WILL INCREASE TODAY AS THE PRESSURE GRADIENT
TIGHTENS AHEAD OF AN APPROACHING COLD FRONT. THE COLD FRONT WILL
SWEEP ACROSS THE LOWER LAKES TONIGHT. FOLLOWING THE FRONT MODERATE
TO STRONG WESTERLIES WILL BRING AN EXTENDED PERIOD OF SMALL CRAFT
CONDITIONS TO BOTH LAKES THROUGH MIDWEEK. WINDS MAY GET CLOSE TO
GALE FORCE AT TIMES MONDAY AND TUESDAY ON LAKE ONTARIO.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 10 PM EDT MONDAY FOR LEZ040-
041.
SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO 6 AM EDT
TUESDAY FOR LOZ042-043.
SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY
FOR LOZ044-045.
&&
$$
SYNOPSIS...TMA
NEAR TERM...TMA
SHORT TERM...WCH
LONG TERM...SMITH/WCH
AVIATION...TMA
MARINE...TMA
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
119 AM EDT SUN MAR 31 2013
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL MOVE THROUGH THE OHIO VALLEY TODAY...PROVIDING
A CHANCE OF RAIN. A COLD FRONT WILL THEN MOVE THROUGH TONIGHT...PROVIDING
COOLER TEMPERATURES FOR THE FIRST PART OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
PCPN IS BEGINNING TO FORM IN SOUTH CENTRAL KY IN RESPONSE TO THE
H5 S/W THAT IS WORKING UP THE OHIO VALLEY. 18Z LOW DEVELOPED A
MORE DEFINED SFC LOW AND MOVED IT ACROSS THE FA OVERNIGHT. THE 00Z
NAM IS A LITTLE LESS DEVELOPED PUT STILL PUSHES THE BEST PCPN
ACROSS THE SE QUARTER OF THE FA BETWEEN 06Z-12Z. THE PREVIOUS
FORECAST HAD THIS SCENARIO...SO ONLY ADJUSTED THE TIMING A LITTLE
AT THE BEGINNING.
TEMPERATURES IN THE E COOLED OFF QUICKLY THIS EVENING WITH THE DRY
DEWPOINTS AND MIGHT DROP A FEW MORE DEGREES BEFORE STARTING TO
RISE TOWARDS MORNING. OVERALL KEPT THE LOWS IN THE PREVIOUS
FORECAST RANGES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/...
A SHORTWAVE CURRENTLY MOVING THROUGH THE MIDDLE MISSISSIPPI VALLEY
WILL BEGIN TO AFFECT THE WESTERN CWA BY 06Z. THE AMPLITUDE OF THIS
SHORTWAVE IS NOT ESPECIALLY STRONG...AND IT IS SOMEWHAT TOUGH TO
DISCERN WHEN LOOKING ONLY AT 500MB HEIGHT CONTOURS. WITH THE DRY
AIR IN PLACE OVER MUCH OF THE OHIO VALLEY RIGHT NOW...IT IS NOT
ENTIRELY SURPRISING THAT THE TREND HAS BEEN TOWARD SLIGHTLY DRIER
SOLUTIONS FOR SUNDAY MORNING. THE SIGNAL FROM THE HIGH-
RESOLUTION OUTPUT IS CONFLICTING...WITH THE 12Z SPC-WRF INDICATING
ONLY SCATTERED SHOWERS (AND SOME BIG DRY PATCHES)...AND THE MOST
RECENT HRRR RUN SHOWING A SOLID AREA OF PRECIPITATION FOR THE
SOUTHERN HALF OF THE CWA. TIMING WAS ADJUSTED ON THE POPS...WITH A
SLIGHTLY ADJUSTMENT DOWNWARD IN VALUE AS WELL...AND NO HIGHER THAN
LIKELY FOR THE SOUTHERN CWA.
AN ASPECT OF THE SYSTEM THAT IS AGREED UPON FROM ALL SOURCES IS A
SPLIT IN THE PRECIPITATION BETWEEN A SOUTHERN AREA OF
PRECIPITATION (PRIMARILY AFFECTING KENTUCKY AND TENNESSEE) AND
WITH A NORTHERN STREAM SYSTEM MOVING THROUGH MICHIGAN. THE
NORTHERN SYSTEM WILL LAG BEHIND THE SOUTHERN SYSTEM BY SEVERAL
HOURS...BUT THIS WILL LIKELY ACT TO INITIATE MORE SHOWERS OVER THE
EASTERN CWA THROUGH MID-AFTERNOON. SPC SREF PARAMETERS INDICATE
THAT SOME WEAK INSTABILITY COULD BUILD IN TO THE SOUTHEASTERN AND
EASTERN CWA DURING THIS TIME FRAME...SO THUNDER WAS KEPT IN THE
FORECAST.
BY SUNDAY NIGHT...A COLD FRONT WILL BE MOVING INTO THE NORTHERN
PORTIONS OF THE CWA. WHILE THE COLD ADVECTION IS NOTABLE BEHIND
THE FRONT...THE SURFACE PRESSURE PATTERN IS WEAK...AND FORCING
IS ALMOST NON-EXISTENT. AS A RESULT OF THIS...THE FRONT SHOULD
PASS THROUGH DRY. HOWEVER...IN A REGION OF COLD ADVECTION BEHIND
THE FRONT...A WEAK RIPPLE IN THE FLOW (ROUNDING THE SOUTHWESTERN
EDGE OF THE LARGE UPPER TROUGH) WILL PASS INTO THE CWA. THIS
FEATURE MAY BRING A BAND OF LIGHT PRECIPITATION DURING THE FIRST
TWO-THIRDS OF MONDAY. HOWEVER...THIS HAS BEEN MODELED DRIER ON THE
LAST SET OF RUNS...SO POPS HAVE BEEN LIMITED TO 20 PERCENT.
TEMPERATURES SUPPORT A MIX OF SNOW AND RAIN (WITH GENERALLY SNOW
IN THE NORTH AND GENERALLY RAIN IN THE SOUTH)...BUT AS QPF IS
EXTREMELY LIGHT...THE DAY SHOULD NOT BE A STRIKEOUT.
WITH THE ONLY SIGNIFICANT TEMPERATURE ADVECTION OCCURRING SUNDAY
NIGHT WITH THE COLD FRONT...TEMPS SHOULD REMAIN GENERALLY DIURNAL
THROUGH THE PERIOD. AFTER A DAY OF COLD ADVECTION AND AS SKIES
CLEAR OUT MONDAY NIGHT...TEMPS APPEAR TO BE SET TO DROP INTO THE
20S...10-15 DEGREES BELOW NORMAL FOR EARLY APRIL.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
DEEP MID LVL TROUGH WILL PROGRESS EASTWARD TUESDAY INTO WEDNESDAY
ALLOWING SFC HIGH PRESSURE TO SETTLE INTO THE GREAT LAKES AND
OHIO VALLEY. ON TUESDAY...THERE COULD BE SOME DIURNALLY DRIVEN
CUMULUS BUT IT LOOKS LIKE MOST OF THE REGION WILL BE MOSTLY SUNNY. IT
SHOULD BE MOSTLY CLEAR TUESDAY NIGHT AND MOSTLY SUNNY ON WEDNESDAY.
COLDEST TEMPERATURES ARE EXPECTED TUESDAY INTO TUESDAY NIGHT. HIGHS
ON TUESDAY WILL RANGE FROM THE UPPER 30S NORTH TO THE MID 40S SOUTH.
LOWS TUESDAY NIGHT WILL DROP INTO THE LOWER AND MID 20S. SOME
MODIFICATION IS EXPECTED ON WEDNESDAY BUT TEMPERATURES WILL REMAIN
BELOW NORMAL FOR EARLY APRIL. HIGHS WILL RANGE FROM THE LOWER 40S NE
TO THE UPPER 40S SOUTHWEST.
UPR LVL FLOW WILL TRANSITION TO A MORE ZONAL PATTERN LATE IN THE
WEEK. THERE WILL BE A SPLIT FLOW BETWEEN NRN STREAM ENERGY AND SRN
STREAM ENERGY. MODELS HAVE BEEN OSCILLATING ON HOW THE NRN STREAM
ENERGY WILL INTERACT WITH THE SRN STREAM ENERGY. FOR NOW...HAVE KEPT
AN UPR LVL LOW AND PCPN WITH THE SRN STREAM ENERGY TO OUR SOUTH AND
EAST THURSDAY INTO FRIDAY WHILE A WEAK COLD FRONT DROPS SOUTHEAST
THROUGH THE REGION THURSDAY NIGHT INTO FRIDAY. TEMPERATURES WILL
CONTINUE TO MODERATE WITH HIGHS IN THE 50S ON THURSDAY AND 50S TO
NEAR 60 ON FRIDAY.
FOR FRIDAY NIGHT INTO SATURDAY...SURFACE HIGH PRESSURE WILL PUSH
INTO THE REGION AND WILL EVENTUALLY MOVE EAST. DRY WEATHER WITH
TEMPERATURES NEAR SEASONAL NORMALS ARE EXPECTED.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS WILL START OUT THE TAF PERIOD. A DISTURBANCE WILL
WORK INTO THE TAF SITES OVERNIGHT AND INTO THE DAYTIME MORNING
HOURS. THIS DISTURBANCE WILL BRING RAIN SHOWERS TO THE AREA.
VSBYS MAY BE REDUCED TO MVFR WITH THE SHOWER ACTIVITY. MVFR CIGS
WILL DEVELOP AND MOVE INTO THE REGION DURING THE MORNING HOURS AND
REMAIN ACROSS THE TAF SITES THROUGH AROUND MID DAY.
EXPECT VFR CONDITIONS TO RETURN TO THE TAF SITES AROUND MID DAY
AND BY THEN MOST OF THE SHOWER ACTIVITY WILL BE OUT OF THE TAF
SITES. SOME RESIDUAL SHOWER ACTIVITY MAY LINGER AT KCMH AND KLCK
INTO THE MID AFTERNOON HOURS.
WINDS WILL PICK UP FOR THE DAYTIME HOURS WITH WINDS GUSTING AROUND
20 TO 25 KNOTS DURING THE AFTERNOON AND EARLY EVENING HOURS. WIND
GUSTS WILL SUBSIDE SUNDAY EVENING HOWEVER EXPECT WINDS TO STAY UP
SOME THROUGH THE NIGHT TONIGHT. ANOTHER DISTURBANCE WILL MOVE
THROUGH TONIGHT AND WILL BRING SOME LIGHT PRECIPITATION TO THE TAF
SITES FOR A COUPLE OF HOURS.
OUTLOOK...MVFR CONDITIONS POSSIBLE ON MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...SITES
SHORT TERM...HATZOS
LONG TERM...HICKMAN
AVIATION...NOVAK
AREA FORECAST DISCUSSION...CORRECTED
NWS MEDFORD OR
1020 PM PDT SAT MAR 30 2013
.DISCUSSION...AN UPDATE HAS BEEN ISSUED TO LOWER THE SUNDAY
MORNING POPS IN SOUTHERN OREGON. THERE STILL MAY BE A FEW SHOWERS
NORTH OF THE BORDER..BUT BEFORE 11 AM ON SUNDAY THE RAP AND GFS
MODELS BOTH SHOW THE LARGE MAJORITY OF THE SHOWERS REMAINING IN
NORTHERN CALIFORNIA. BY THE AFTERNOON...THE DEFORMATION BAND WILL
SHIFT NORTHWARD WITH THE HIGHEST QPF LIKELY OCCURRING NEAR THE
OREGON/CALIFORNIA BORDER.
THE BROAD CLOSED UPPER LOW OFFSHORE FROM SAN FRANCISCO ALONG 130W
IS MOVING EAST-NORTHEAST AND WILL MOVE INLAND BY SUNDAY EVENING. A
SHORTWAVE ROTATING AROUND THE LOW HELPED THUNDERSTORMS TO DEVELOP
OVER THE NORTHERN SIERRA NEVADA THIS AFTERNOON THEN BY EARLY
EVENING THEY SPREAD INTO EASTERN SISKIYOU COUNTY BEFORE CONTINUING
NORTHWESTWARD ACROSS YREKA AND SEIAD VALLEY. AFTER 630 PM...A
MULTI-CELLULAR THUNDERSTORM STRENGTHENED OVER THE APPLEGATE VALLEY
AND MOVED ACROSS THE GRANTS PASS...MERLIN AND WILDERVILLE AREA.
BESIDES LIGHTNING...THE MAIN DISTINGUISHING CHARACTERISTIC WAS
GUSTY DOWNDRAFT WINDS. THIS INCLUDED A GUST TO 38 MPH MEASURED AT
THE MEDFORD AIRPORT AND ESTIMATED GUSTS OF 40 TO 50 MPH ACROSS
CENTRAL JOSEPHINE COUNTY. THE THUNDERSTORMS WERE AT THEIR
STRONGEST BETWEEN 7 PM AND 8 PM AND THE STRONGEST OF THE CELLS IS
FINALLY WEAKENING NOW NEAR AGNESS AND GOLD BEACH IN CURRY COUNTY.
MOVING FORWARD...THE SOUTHEAST WINDS ALOFT WILL BACK TO THE EAST TONIGHT
WITH A SLIGHT CHANCE OF ADDITIONAL THUNDERSTORMS BUT MAINLY SIMPLY
SCATTERED LIGHT TO MODERATE SHOWERS. FOR EASTER SUNDAY...ANOTHER COUPLE
OF STRONGER SHORTWAVES THAT ARE PRESENTLY REACHING SOUTHERN
CALIFORNIA WILL BRING AN INCREASE IN COVERAGE AND INTENSITY OF SHOWERS.
THE ACTIVITY OVERNIGHT INTO SUNDAY MORNING WILL BE FOCUSED FROM
THE SIERRA NEVADA INTO SISKIYOU COUNTY BUT BY MID TO LATE MORNING
THEN THROUGH SUNDAY NIGHT RAIN SHOWERS ARE LIKELY ACROSS OUR AREA AND
THERE WILL BE A SLIGHT CHANCE OF THUNDERSTORMS. THE SHOWERY NATURE
OF THE PRECIPITATION WILL LIKELY LEAD TO A WIDE RANGE OF QPF
AMOUNTS BUT AMOUNTS OF A QUARTER TO A HALF OF AN INCH SHOULD BE
COMMON.
THE UPPER LOW IS FORECAST TO EXIT EAST INTO NEVADA ON MONDAY BUT
WRAP-AROUND SHOWERS ARE LIKELY...ESPECIALLY IN THE MORNING AND EAST
OF THE CASCADES.
HIGH PRESSURE WILL BRING A RETURN OF WARM AND DRY WEATHER TUESDAY
THROUGH WEDNESDAY THEN A SERIES OF FRONTAL SYSTEMS WILL LIKELY BRING
WET AND COOLER WEATHER FOR THE REMAINDER OF THE WEEK.
&&
.AVIATION...
BASED ON THE 31/00Z TAF CYCLE.
IFR CONDITIONS WILL DEVELOP OVERNIGHT ALONG THE COAST AS ONSHORE
FLOW CONTINUES. SHOWERS AND ISOLATED THUNDERSTORMS ARE LIKELY TO
REMAIN MOSTLY FROM THE SISKIYOUS AND THE CURRY AND JOSEPHINE
COUNTY COASTAL MOUNTAINS SOUTHWARD OVERNIGHT. MVFR CONDITIONS WILL
DEVELOP ACROSS THE WEST SIDE DURING THE DAY ON EASTER SUNDAY.
THERE WILL BE A THREAT OF THUNDERSTORMS AS WELL AS SHOWERS THAT
WILL BE MODERATE TO LOCALLY HEAVY AT TIMES FROM ABOUT THE MEDFORD
AREA SOUTHWARD AND EASTWARD DURING THE AFTERNOON AND EVENING. BTL
&&
.PREV DISCUSSION... /ISSUED 256 PM PDT SAT MAR 30 2013/
SHORT TERM...A CUTOFF LOW OFF THE CENTRAL CALIFORNIA COAST
REMAINS THE MAIN WEATHER MAKER FOR THE NEXT COUPLE DAYS. THIS LOW
IS MOVING TOWARDS THE REGION TODAY AND IS FORECAST TO MOVE INLAND
SUNDAY AND MONDAY. THEN A HIGH PRESSURE RIDGE WILL BRING WARM AND
DRY CONDITIONS BEGINNING TUESDAY.
AHEAD OF THIS LOW...MOISTURE AND INSTABILITY ARE INCREASING TODAY.
ISOLATED THUNDERSTORMS HAVE DEVELOPED EARLY THIS AFTERNOON TO THE
SOUTH IN LASSEN AND SHASTA COUNTY WHERE THE BEST LIFT IS INDICATED
IN THE MESO ANALYSIS AND RAP FORECAST. ALSO, MESO ANALYSIS SHOWS
PRECIPITABLE WATER VALUES OF 0.8 INCHES ALONG THE NORTHERN
CALIFORNIA COAST. INLAND PW AMOUNTS RANGE FROM 0.4 TO 0.7 INCHES AND
WILL INCREASE LATE THIS AFTERNOON AND THIS EVENING AS MOISTURE
MOVES UP FROM THE SOUTH AND SOUTHEAST INTO THE AREA. DAYTIME
HEATING WILL RESULT IN SURFACE BASED INSTABILITY AND MODELS SHOW
INCREASING LIFT OVER CENTRAL PORTIONS AND SOUTHERN PORTIONS OF
THE AREA IN THE LATE AFTERNOON AND EVENING. ALSO MODELS SHOW THAT
CAPE WILL INCREASE FROM THE CASCADES WEST DURING THIS PERIOD. THE
INCREASE IN MOISTURE...LIFT AND INSTABILITY WILL ALLOW SHOWERS AND
ISOLATED THUNDERSTORMS TO DEVELOP LATE THIS AFTERNOON INTO THIS
EVENING OVER SISKIYOU AND MODOC COUNTIES IN NORTHERN CALIFORNIA
AND OVER SOUTHWESTERN PORTIONS OF SOUTHERN OREGON....MAINLY FROM
KLAMATH COUNTY WEST. ADDITIONALLY A BAND OF SHOWERS IS EXPECTED TO
MOVE INTO THE CWA FROM THE SOUTH LATE THIS EVENING AND TONIGHT.
SOME ISOLATED EMBEDDED THUNDERSTORMS AS WELL AS AREAS OF MODERATE
TO HEAVY RAIN ARE ALSO POSSIBLE WITH THIS LINE.
ON SUNDAY...THE LOW BEGINS TO MOVES INLAND TO THE SOUTH AND WILL
BRING CONTINUED MOISTURE AND SHOWERS TO THE AREA. BY
AFTERNOON...EXPECT SHOWERS TO BECOME WIDESPREAD OVER MOST THE
AREA. INSTABILITY INCREASES OVER THE AREA AGAIN SUNDAY
AFTERNOON. HAVE EXPANDED THE SLIGHT RISK OF THUNDERSTORMS OVER THE
INLAND AREAS SUNDAY AFTERNOON INTO SUNDAY EVENING GIVEN THE MODEL
CONSENSUS ON BETTER INSTABILITY...AS WELL AS INCREASED DIVERGENCE
ALOFT AND CONTINUED MOISTURE CONVERGENCE OVER PORTIONS OF THE CWA.
ON MONDAY...MODELS CONTINUE TO SHOW DIFFERENCES ON THE SPEED OF
THE LOW AS IT MOVES EAST INTO NEVADA AND UTAH WITH THE ECMWF
BEING SLOWER THAN THE GFS AND NAM. HAVE COMPROMISED IN THE
FORECAST WITH CHANCE POPS OVER THE CENTRAL AND EASTERN PORTIONS OF
THE CWA AND A SLIGHT CHANCE ELSEWHERE. BY MONDAY NIGHT EXPECT
SHOWER ACTIVITY TO DIMINISH ACROSS THE AREA AS A STRONG RIDGE OF
HIGH PRESSURE BUILDS INTO PLACE.
ON TUESDAY...A RIDGE WILL BRING DRY AND VERY WARM CONDITIONS WITH
HIGHS IN THE UPPER 60S TO MID 70S FOR VALLEYS WEST OF THE CASCADES
AND IN THE MID 60S EAST OF THE CASCADES. THESE WARM AND DRY
CONDITIONS CONTINUE INTO WEDNESDAY.
LONG TERM...AN ACTIVE PATTERN IS IN THE WORKS STARTING NEXT
THURSDAY AND COULD LAST THROUGH NEXT WEEKEND. THE EC AND GFS
OPERATIONAL AND ENSEMBLE MEANS HAVE BEEN TRENDING IN THIS DIRECTION
FOR THE PAST FEW DAYS. SO CONFIDENCE IS BECOMING HIGHER WE`LL BE
HEADING INTO A COOLER AND WETTER PATTERN....BUT LESS CONFIDENT ON
THE TIMING OF EACH INDIVIDUAL SYSTEM. THE EC IS SLOWER THEN THE
GFS WITH A NEGATIVE TILTED TROUGH MOVING INTO THE AREA THURSDAY
AFTERNOON. SO WE`LL CONTINUE TO GO ABOVE CLIMO FROM THURSDAY
ONWARD IN THE EXTENDED. TEMPERATURES ARE ALSO LIKELY TO BE BELOW
NORMAL DURING THE DAY...BUT NEAR OR SLIGHTLY ABOVE NORMAL AT NIGHT
DUE TO CLOUD COVER AND PRECIPITATION. -PETRUCELLI
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
DW/BTL/NSK
AREA FORECAST DISCUSSION
NWS MEDFORD OR
913 PM PDT SAT MAR 30 2013
.DISCUSSION...THE BROAD CLOSED UPPER LOW OFFSHORE FROM SAN
FRANCISCO ALONG 130W IS MOVING EAST-NORTHEAST AND WILL MOVE INLAND
BY SUNDAY EVENING. A SHORTWAVE ROTATING AROUND THE LOW HELPED
THUNDERSTORMS TO DEVELOP OVER THE NORTHERN SIERRA NEVADA THIS
AFTERNOON THEN BY EARLY EVENING THEY SPREAD INTO EASTERN SISKIYOU
COUNTY BEFORE CONTINUING NORTHWESTWARD ACROSS YREKA AND SEIAD
VALLEY. AFTER 630 PM...A MULTI-CELLULAR THUNDERSTORM STRENGTHENED
OVER THE APPLEGATE VALLEY AND MOVED ACROSS THE GRANTS
PASS...MERLIN AND WILDERVILLE AREA. BESIDES LIGHTNING...THE MAIN
DISTINGUISHING CHARACTERISTIC WAS GUSTY DOWNDRAFT WINDS. THIS
INCLUDED A GUST TO 38 MPH MEASURED AT THE MEDFORD AIRPORT AND ESTIMATED
GUSTS OF 40 TO 50 MPH ACROSS CENTRAL JOSEPHINE COUNTY. THE THUNDERSTORMS
WERE AT THEIR STRONGEST BETWEEN 7 PM AND 8 PM AND THE STRONGEST OF
THE CELLS IS FINALLY WEAKENING NOW NEAR AGNESS AND GOLD BEACH IN CURRY
COUNTY.
MOVING FORWARD...THE SOUTHEAST WINDS ALOFT WILL BACK TO THE EAST TONIGHT
WITH A SLIGHT CHANCE OF ADDITIONAL THUNDERSTORMS BUT MAINLY SIMPLY
SCATTERED LIGHT TO MODERATE SHOWERS. FOR EASTER SUNDAY...ANOTHER COUPLE
OF STRONGER SHORTWAVES THAT ARE PRESENTLY REACHING SOUTHERN
CALIFORNIA WILL BRING AN INCREASE IN COVERAGE AND INTENSITY OF SHOWERS.
THE ACTIVITY OVERNIGHT INTO SUNDAY MORNING WILL BE FOCUSED FROM
THE SIERRA NEVADA INTO SISKIYOU COUNTY BUT BY MID TO LATE MORNING
THEN THROUGH SUNDAY NIGHT RAIN SHOWERS ARE LIKELY ACROSS OUR AREA AND
THERE WILL BE A SLIGHT CHANCE OF THUNDERSTORMS. THE SHOWERY NATURE
OF THE PRECIPITATION WILL LIKELY LEAD TO A WIDE RANGE OF QPF
AMOUNTS BUT AMOUNTS OF A QUARTER TO A HALF OF AN INCH SHOULD BE
COMMON.
THE UPPER LOW IS FORECAST TO EXIT EAST INTO NEVADA ON MONDAY BUT
WRAP-AROUND SHOWERS ARE LIKELY...ESPECIALLY IN THE MORNING AND EAST
OF THE CASCADES.
HIGH PRESSURE WILL BRING A RETURN OF WARM AND DRY WEATHER TUESDAY
THROUGH WEDNESDAY THEN A SERIES OF FRONTAL SYSTEMS WILL LIKELY BRING
WET AND COOLER WEATHER FOR THE REMAINDER OF THE WEEK.
&&
.AVIATION...
BASED ON THE 31/00Z TAF CYCLE.
IFR CONDITIONS WILL DEVELOP OVERNIGHT ALONG THE COAST AS ONSHORE
FLOW CONTINUES. SHOWERS AND ISOLATED THUNDERSTORMS ARE LIKELY TO
REMAIN MOSTLY FROM THE SISKIYOUS AND THE CURRY AND JOSEPHINE
COUNTY COASTAL MOUNTAINS SOUTHWARD OVERNIGHT. MVFR CONDITIONS WILL
DEVELOP ACROSS THE WEST SIDE DURING THE DAY ON EASTER SUNDAY.
THERE WILL BE A THREAT OF THUNDERSTORMS AS WELL AS SHOWERS THAT
WILL BE MODERATE TO LOCALLY HEAVY AT TIMES FROM ABOUT THE MEDFORD
AREA SOUTHWARD AND EASTWARD DURING THE AFTERNOON AND EVENING. BTL
&&
.PREV DISCUSSION... /ISSUED 256 PM PDT SAT MAR 30 2013/
SHORT TERM...A CUTOFF LOW OFF THE CENTRAL CALIFORNIA COAST
REMAINS THE MAIN WEATHER MAKER FOR THE NEXT COUPLE DAYS. THIS LOW
IS MOVING TOWARDS THE REGION TODAY AND IS FORECAST TO MOVE INLAND
SUNDAY AND MONDAY. THEN A HIGH PRESSURE RIDGE WILL BRING WARM AND
DRY CONDITIONS BEGINNING TUESDAY.
AHEAD OF THIS LOW...MOISTURE AND INSTABILITY ARE INCREASING TODAY.
ISOLATED THUNDERSTORMS HAVE DEVELOPED EARLY THIS AFTERNOON TO THE
SOUTH IN LASSEN AND SHASTA COUNTY WHERE THE BEST LIFT IS INDICATED
IN THE MESO ANALYSIS AND RAP FORECAST. ALSO, MESO ANALYSIS SHOWS
PRECIPITABLE WATER VALUES OF 0.8 INCHES ALONG THE NORTHERN
CALIFORNIA COAST. INLAND PW AMOUNTS RANGE FROM 0.4 TO 0.7 INCHES AND
WILL INCREASE LATE THIS AFTERNOON AND THIS EVENING AS MOISTURE
MOVES UP FROM THE SOUTH AND SOUTHEAST INTO THE AREA. DAYTIME
HEATING WILL RESULT IN SURFACE BASED INSTABILITY AND MODELS SHOW
INCREASING LIFT OVER CENTRAL PORTIONS AND SOUTHERN PORTIONS OF
THE AREA IN THE LATE AFTERNOON AND EVENING. ALSO MODELS SHOW THAT
CAPE WILL INCREASE FROM THE CASCADES WEST DURING THIS PERIOD. THE
INCREASE IN MOISTURE...LIFT AND INSTABILITY WILL ALLOW SHOWERS AND
ISOLATED THUNDERSTORMS TO DEVELOP LATE THIS AFTERNOON INTO THIS
EVENING OVER SISKIYOU AND MODOC COUNTIES IN NORTHERN CALIFORNIA
AND OVER SOUTHWESTERN PORTIONS OF SOUTHERN OREGON....MAINLY FROM
KLAMATH COUNTY WEST. ADDITIONALLY A BAND OF SHOWERS IS EXPECTED TO
MOVE INTO THE CWA FROM THE SOUTH LATE THIS EVENING AND TONIGHT.
SOME ISOLATED EMBEDDED THUNDERSTORMS AS WELL AS AREAS OF MODERATE
TO HEAVY RAIN ARE ALSO POSSIBLE WITH THIS LINE.
ON SUNDAY...THE LOW BEGINS TO MOVES INLAND TO THE SOUTH AND WILL
BRING CONTINUED MOISTURE AND SHOWERS TO THE AREA. BY
AFTERNOON...EXPECT SHOWERS TO BECOME WIDESPREAD OVER MOST THE
AREA. INSTABILITY INCREASES OVER THE AREA AGAIN SUNDAY
AFTERNOON. HAVE EXPANDED THE SLIGHT RISK OF THUNDERSTORMS OVER THE
INLAND AREAS SUNDAY AFTERNOON INTO SUNDAY EVENING GIVEN THE MODEL
CONSENSUS ON BETTER INSTABILITY...AS WELL AS INCREASED DIVERGENCE
ALOFT AND CONTINUED MOISTURE CONVERGENCE OVER PORTIONS OF THE CWA.
ON MONDAY...MODELS CONTINUE TO SHOW DIFFERENCES ON THE SPEED OF
THE LOW AS IT MOVES EAST INTO NEVADA AND UTAH WITH THE ECMWF
BEING SLOWER THAN THE GFS AND NAM. HAVE COMPROMISED IN THE
FORECAST WITH CHANCE POPS OVER THE CENTRAL AND EASTERN PORTIONS OF
THE CWA AND A SLIGHT CHANCE ELSEWHERE. BY MONDAY NIGHT EXPECT
SHOWER ACTIVITY TO DIMINISH ACROSS THE AREA AS A STRONG RIDGE OF
HIGH PRESSURE BUILDS INTO PLACE.
ON TUESDAY...A RIDGE WILL BRING DRY AND VERY WARM CONDITIONS WITH
HIGHS IN THE UPPER 60S TO MID 70S FOR VALLEYS WEST OF THE CASCADES
AND IN THE MID 60S EAST OF THE CASCADES. THESE WARM AND DRY
CONDITIONS CONTINUE INTO WEDNESDAY.
LONG TERM...AN ACTIVE PATTERN IS IN THE WORKS STARTING NEXT
THURSDAY AND COULD LAST THROUGH NEXT WEEKEND. THE EC AND GFS
OPERATIONAL AND ENSEMBLE MEANS HAVE BEEN TRENDING IN THIS DIRECTION
FOR THE PAST FEW DAYS. SO CONFIDENCE IS BECOMING HIGHER WE`LL BE
HEADING INTO A COOLER AND WETTER PATTERN....BUT LESS CONFIDENT ON
THE TIMING OF EACH INDIVIDUAL SYSTEM. THE EC IS SLOWER THEN THE
GFS WITH A NEGATIVE TILTED TROUGH MOVING INTO THE AREA THURSDAY
AFTERNOON. SO WE`LL CONTINUE TO GO ABOVE CLIMO FROM THURSDAY
ONWARD IN THE EXTENDED. TEMPERATURES ARE ALSO LIKELY TO BE BELOW
NORMAL DURING THE DAY...BUT NEAR OR SLIGHTLY ABOVE NORMAL AT NIGHT
DUE TO CLOUD COVER AND PRECIPITATION. -PETRUCELLI
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
DW/BTL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
434 AM EDT SUN MAR 31 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION FROM THE WEST TONIGHT...WITH A
SECOND COLD FRONT MOVING OVER THE AREA MONDAY NIGHT. HIGH PRESSURE
WILL FILL IN BEHIND THE SECOND FRONT USHERING IN COOLER THAN NORMAL
TEMPERATURES THROUGH THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
430 AM EDT UPDATE...NO SIGFNT CHANGES NEED TO THE FCST. TEMPS AND
TD/S ARE PRETTY MUCH LOCKED IN WITH THE SATURATED SFC LAYER
CWFA/WIDE. POPS ARE STILL LOOKING GOOD WITH RADAR TRENDS AND HI/RES
MODEL OUTPUT. IN FACT...THE LATEST HRRR AGREES WELL WITH THE 00Z WRF
MODELS WITH THE MOVEMENT AND MASS FIELDS ASSOCIATED WITH THE WARM
FRONT. THIS GIVES GOOD CONFIDENCE IN THE EXPECTED GENERAL WANING OF
PRECIP...WHICH THE MAJORITY SHOULD BE PUSHING EAST OF THE FCST AREA
BY 13Z/14Z. PRECIP AMOUNTS PER THE RAIN GAUGE NETWORK AND COMP RADAR
IS RIGHT ON TRACK WITH THE FCST/D AMOUNTS AND PLACEMENT.
AS OF 305 AM EDT SUNDAY...A WARM FRONT IS BISECTING THE CWFA ATTM
WITH A WIDESPREAD PRECIP SHIELD REACHING NEARLY ALL ZONES EXCEPT THE
FAR NW/RN COUNTIES. HYDROVIEW IS SHOWING 8-HR PRECIP AMOUNTS RANGING
FROM A HALF AN INCH ACROSS NE GA TO LESS THAN A TENTH EAST OF I-26.
BASED ON EXPECTED RADAR TRENDS...THIS FITS WELL WITH THE OVERALL
FCST/D AMOUNTS THROUGH 12Z. EXPECT ANOTHER HALF INCH OR SO ACROSS
THE ERN HALF OF THE CWFA AND PERHAPS A COUPLE MORE TENTHS WEST BY
THE TIME THE FRONT PUSHES NE OF THE AREA AROUND 14Z. NO HYDRO
CONCERNS ARE HAD WITH THIS BENEFICIAL RAINFALL.
THE AREA WILL REMAIN IN SMALL WARM SECTOR TODAY AND A FAIRLY TIGHT
P/GRAD WILL DEVELOP ASSOCIATED WITH THE OVERALL COMPACT SYSTEM. THIS
WILL ENABLE SUSTAINED WINDS OF 12+ KTS THIS AFTERNOON...YET WITH LOW
END GUSTS DUE TO THE WAA PATTERN AND RISING MOTION. THE SW SFC FLOW
WILL ALLOW TD/S TO MODIFY INTO THE L50S ACROSS THE SW/RN ZONES AND
THIS WILL PROBABLY BE ENOUGH FOR ISOL THUNDER LATE THIS AFTERNOON...
ENDING QUICKLY AFT 00Z. SOUNDINGS SHOW UNIDIRECTIONAL AND RELATIVELY
WEAK SHEAR ALONG WITH SHALLOW AND LOW SBCAPE...WHILE UPPER DIV IS
AND SYNOPTIC FORCING IS DISPLACED NORTH OF THE BEST THERMODYNAMICAL
REGION. SO...WILL ANTICIPATE GENERAL TS WITH CTG LIGHTNING AS THE
MAIN THREAT.
THE COLD FRONT ADVANCES UPON THE CWFA TONIGHT AND INCREASES THE DEEP
LAYERED LIFT. HOWEVER...WITH A NOCTURNAL FROPA...DON/T ANTICIPATE
MUCH MORE THAN -SHRA WITH RELATIVELY LOW QPF. THE FRONT ITSELF IS
DISJOINTED FROM IT/S PARENT OCCLUDED SFC LOW BY 06Z AND WILL HAVE
NEGLIGIBLE UPPER SUPPORT. THUS...THE BEST LIFT WILL BE MECH ACROSS
THE MTNS AND TO THE SW OF THE CWFA ASSOCIATED WITH A LLVL THETA/E
RIDGE. THE FAR SRN ZONES COULD SEE A NEW 12-HR RAINFALL OF 0.25
INCHES WITH QUICKLY DIMINISHING AMOUNTS TO THE NORTH THROUGH 12Z.
MAX TEMPS WILL BE SEASONAL...PERHAPS A COUPLE DEGREES ABOVE WITH
SOME BRIEF SCATTERING AND DECENT WAA. MINS WILL REMAIN ABOUT 6-8
DEGREES ABOVE NORMAL WITH PLENTY OF CLOUD COVER/PRECIP AND A NW/LY
WIND SHIFT NOT OCCURRING UNTIL AROUND 10Z.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 245 AM SUNDAY...THE SHORT RANGE CONTINUES TO BE VEXED BY
UNCERTAINTY WITH THE MODEL GUIDANCE...MOSTLY WITH HOW TO HANDLE THE
LOCATION AND ACTIVITY ALONG TWO SURFACE COLD FRONTS. STARTING MONDAY
MORNING...THE FIRST FRONT SHOULD BE LAID DOWN ACROSS THE COASTAL
PLAIN...BUT THE BACK EDGE OF LIGHT PRECIP MIGHT STILL LINGER ACROSS
THE SOUTHEASTERN ZONES. THAT FRONT SHOULD GET SOME ADDITIONAL
EASTWARD PUSH IN THE MORNING...SO THINK ANY REMNANT PRECIP SHOULD
LEAVE THE EASTERN ZONES EARLY IN THE DAY. MEANWHILE...THE NEXT FRONT
WILL BE APPROACHING FROM THE NW...WITH SOME UPSLOPE FLOW OF MOISTURE
AT LOW LEVELS INTO THE NC MTNS. BOTH MODELS SHOW SOME UPSLOPE PRECIP
THROUGH THE AFTERNOON HOURS SO A CHANCE POP WAS KEPT ON THE TN
BORDER THROUGH MIDDAY...BUT THEN DIMINISHES BY EVENING AS MOISTURE
WILL BE LESS THAN IMPRESSIVE. IN BETWEEN...DO NOT EXPECT MUCH TO
HAPPEN ACROSS THE MAJORITY OF THE FCST AREA...BECAUSE OF A LACK OF
FORCING AND MOISTURE. INSTEAD...WE SHOULD EXPECT ANOTHER SEASONALLY
WARM DAY WITH A WNW FLOW PROVIDING SOME DOWNSLOPE E OF THE MTNS THAT
WILL HELP GET TEMPS A CATEGORY OR SO ABOVE NORMAL.
FROM MONDAY EVENING ONWARD...CONFIDENCE SUFFERS A BIT. THE NAM
MAINTAINS NW FLOW PRECIP ON THE TN BORDER THROUGH MONDAY NIGHT AND
INTO TUESDAY MORNING WITH TEMPS COOL ENOUGH FOR MORE SNOW. THE GFS
REMAINS DRY. NO CHANGES WILL BE MADE TO THE DRY FCST THAT WAS
INHERITED. IN FACT...THE FCST WAS KEPT GFS-LIKE AND DRY THROUGH THE
REST OF THE SHORT RANGE. THE SECOND FRONT SHOULD DROP DOWN ACROSS
THE FCST AREA EARLY TUESDAY WHICH SHOULD DROP TEMPS BACK TWO
CATEGORIES BELOW NORMAL. NOT READY TO BUY THE NAM SOLUTION OF MOVING
AN AREA OF PRECIP ALONG THIS FRONT TUESDAY...AGAIN WITH POTENTIAL
PRECIP TYPE ISSUES OVER THE MTNS. THE GFS EVENTUALLY BRINGS SOME
LIGHT PRECIP AMTS ACROSS THE REGION FROM THE WEST TUESDAY NIGHT. CAN
ENVISION SOMETHING FALLING OUT OF A MID LEVEL CLOUD DECK BUT IT
PROBABLY WOULD NOT AMT TO MUCH. SIMILAR TO MONDAY NIGHT...HAVE KEPT
AN ALREADY DRY FCST THE SAME WAY.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 315 AM SUNDAY...STARTING TO SEE SOME BETTER AGREEMENT AND RUN
TO RUN CONSISTENCY OUT OF THE MEDIUM RANGE GUIDANCE WITH RESPECT TO
THE NEXT SYSTEM EXPECTED DURING THE LATTER HALF OF THE WEEK. THE 00Z
RUNS OF THE GFS AND ECMWF ACTIVATE THE OLD FRONTAL BOUNDARY TO OUR
SOUTH ON WEDNESDAY NIGHT WITH MOISTURE RETURNING FROM THE GULF OVER
THE TOP OF A COOL AND DRY LOW LEVEL AIR MASS WITH HIGH PRESSURE
MOVING OVER THE MID-ATLANTIC REGION. ISENTROPIC LIFT GETS GOING
BEFORE SUNRISE ON THURSDAY AND REMAINS PRODUCTIVE INTO THURSDAY
NIGHT WITH PLENTY OF ATLANTIC AND GULF MOISTURE. WILL FOLLOW THE
LEAD OF THE NEWER HPC GUIDANCE AND GET A JUMP ON RAISING PRECIP
CHANCES INTO THE LIKELY RANGE FOR THURSDAY AND THURSDAY NIGHT...WITH
A CHANCE LINGERING INTO FRIDAY. AM SKEPTICAL ABOUT THE EXTENT OF ANY
WINTRY PRECIP EARLY THURSDAY AS GFS FCST SOUNDINGS ARE NOT REALLY
SUPPORTIVE OF ANYTHING BUT RAIN. WILL ALSO HAVE TO CONSIDER LOWERING
MAX TEMPS ON FRIDAY IF PRECIP LINGERS LONG ENOUGH. THE REST OF THE
MEDIUM RANGE WAS LEFT ALONE FOR NOW.
&&
.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
AT KCLT AND ELSEWHERE...PRECIP SHIELD IS MAKING IT/S WAY NE ACROSS
THE CWFA AHEAD OF A WARM FRONT. SOME EMBEDDED HEAVIER SHOWERS HAVE
PRODUCED VSBY/S IN THE IFR RANGE...BUT MOST OF THE PRECIP HAS BEEN
LIGHTER. MOS GUIDANCE AND MODEL SOUNDINGS AGREE WITH THE DEVELOPMENT
OF IFR CIGS THIS MORNING AT ALL SITES EXCEPT KAND WHERE CIGS WERE
HELD AT MVFR. THE SFC P/GRAD TIGHTENS AFT SUNRISE AND LOW END GUSTS
SHOULD DEVELOP OUTSIDE THE MTNS AND FOOTHILLS THROUGH THE AFTERNOON
WITH THE AREA REMAINING IN A SLIGHT WAA PATTERN. THE ATMOS WILL
LIKELY BECOME RELATIVELY UNSTABLE ACROSS THE SRN MOST ZONES THIS
AFTERNOON...AND A PROB30 TS IS IN PLACE AFT 17Z FOR A FEW HRS AT
KAND AND KCLT.
OUTLOOK...FAIR WEATHER EXPECTED ON MON. ANOTHER COLD FRONT MOVES
THROUGH ON TUESDAY...BUT RESTRICTIONS LOOK DOUBTFUL WITH THIS
SYSTEM. DRY HIGH PRESSURE SETTLE OVER THE AREA ON WEDNESDAY.
CONFIDENCE TABLE...
08-14Z 14-20Z 20-02Z 02-08Z
KCLT MED 71% HIGH 81% HIGH 100% HIGH 100%
KGSP HIGH 81% HIGH 94% HIGH 100% HIGH 95%
KAVL MED 73% HIGH 87% HIGH 100% HIGH 100%
KHKY MED 73% HIGH 82% HIGH 100% HIGH 100%
KGMU MED 76% HIGH 93% HIGH 100% HIGH 100%
KAND HIGH 94% HIGH 91% HIGH 100% HIGH 98%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...SBK
NEAR TERM...SBK
SHORT TERM...PM
LONG TERM...PM
AVIATION...SBK
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1149 PM CDT SAT MAR 30 2013
.AVIATION...
NO MAJOR CHANGES FROM THE EARLIER TAF FORECAST. CHALLENGES ON
TIMING MVFR CIGS...THUNDERSTORMS...AND THE COLD FRONT REMAIN.
OUTSIDE OF AN ISOLATED SEVERE STORM IN SOUTHERN OKLAHOMA MOVING
TOWARD THE ARKLATEX LATE THIS EVENING...LARGE SCALE ASCENT FROM A
SHORTWAVE LIFTING OUT OF THE ROCKIES CAN NOW BE SEEN ON REGIONAL
RADAR AROUND THE OK/TX PANHANDLES. VFR CONDITIONS WILL CONTINUE
THROUGH 10Z AT DFW AIRPORTS AND 08Z AT WACO...BEFORE MVFR CIGS
SEEN DEVELOPING ALONG THE COASTAL BEND ARRIVE INTO THE AIRPORTS.
MODELS HAVE SLOWED THE COLD FRONT AND ARRIVAL OF A THUNDERSTORM
COMPLEX UNTIL CLOSER TO MID MORNING SUNDAY FOR THE METRO AIRPORTS....
THEN TOWARD MIDDAY OR EARLY AFTERNOON AT WACO. WILL HOLD ON TO 3
HOUR TEMPO GROUP OF IFR CONDITIONS WITH THE HEAVIER RAINFALL WITH
THE ACTIVITY.
WINDS WILL START OFF ESE 5-10 KTS...THEN BECOME SE AROUND 10 KTS
BEFORE SUNRISE AS STORM-RELATIVE INFLOW INCREASES AHEAD OF THE
STORM COMPLEX MOVING SOUTHEAST THROUGH OKLAHOMA. WINDS BEHIND THE
COLD FRONT WILL SHIFT TO THE NORTH 10-15 KTS...BEFORE VEERING
NORTHEAST 5-10 KTS EVENING.
05/
&&
.UPDATE...
IT IS QUIET ACROSS THE REGION AT THIS TIME BUT ANOTHER COMPLEX OF
STORMS IS EXPECTED TO CROSS OUT OF OKLAHOMA AND INTO NORTH TEXAS
NEAR DAYBREAK SUNDAY MORNING. BOTH THE LATEST NAM AND OCCASIONAL
RUNS OF THE RAP DEVELOP STORMS AROUND AND/OR NORTHEAST OF THE DFW
METROPLEX AROUND 4 AM. THE LATEST RUN OF THE RAP DOES NOT HAVE
THESE STORMS. AROUND 4 AM...THE MODELS STILL HAVE THE BEST LIFT
WEST OF THE REGION BUT SOME WEAK HEIGHT FALLS MAY BE STARTING TO
SPREAD EAST AS A SHORTWAVE APPROACHES THE REGION FROM THE WEST.
ISENTROPIC LIFT LOOKS TO BE FAIRLY WEAK AT THIS TIME WITH SOME
WEAK LIFT ON THE 295K SURFACE. BUFR SOUNDINGS AT THIS TIME SHOW A
WELL CAPPED ENVIRONMENT WITH NOT MUCH MOISTURE OR INSTABILITY
ABOVE THE CAP. THEREFORE...THINK IT WILL BE DIFFICULT FOR STORMS
TO DEVELOP THIS EARLY BUT NOT ENTIRELY IMPOSSIBLE.
INSTEAD...THE MAIN FOCUS FOR THE OVERNIGHT PERIOD SHIFTS TO THE
COMPLEX OF STORMS OR MCS THAT WILL DEVELOP ALONG THE COLD FRONT IN
OKLAHOMA AND MARCH SOUTHEAST INTO NORTH TEXAS. THE BEST TIMING
FOR THESE STORMS TO CROSS THE RED RIVER NEAR MONTAGUE AND COOKE
COUNTIES IS AROUND 5-6 AM. THEREFORE...TRENDED HIGHEST POPS BACK
TO THE WEST SOME AND ALSO TRIMMED ACROSS THE SOUTH SOME DUE TO THE
SLIGHTLY SLOWER ARRIVAL TIME. BECAUSE OF THIS SLOWER TIME...ALSO
ADJUSTED THE HIGHER POPS SUNDAY MORNING FARTHER NORTH AND WEST. AT
THE TIME THE STORMS ARRIVE...THE CAP WILL BE WEAK OR ERODED AND
THERE WILL BE A THREAT FOR SEVERE STORMS PRODUCING HAIL AND
DAMAGING WINDS. SOME ADDITIONAL DECENT RAINFALL IS ALSO LIKELY
WITH THIS STORM SYSTEM...ESPECIALLY OVER THE NORTHERN AND EASTERN
COUNTIES.
ADDITIONAL STORMS WILL ALSO BE POSSIBLE SUNDAY AFTERNOON ACROSS
THE SOUTHERN COUNTIES WHERE THE FRONT WILL BE LOCATED IN THE
AFTERNOON HOURS. THESE STORMS COULD POTENTIALLY BE SEVERE AS WELL.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 351 PM CDT SAT MAR 30 2013/
SOMEWHAT OF A COMPLEX SURFACE PATTERN IN PLACE ACROSS THE SOUTHERN
PLAINS THIS AFTERNOON WHICH WILL AFFECT WHICH AREAS SEE
THUNDERSTORMS OVER THE NEXT 12 HOURS. A BROAD SURFACE LOW PERSISTS
ACROSS FAR WEST TEXAS NEAR LUBBOCK WITH WHAT HAS BEEN A QUASI
STATIONARY FRONTAL BOUNDARY EXTENDING TO THE NORTHEAST INTO
SOUTHERN KANSAS. THIS ELONGATED TROUGH WILL BECOME A WELL DEFINED
COLD FRONT BY LATE TONIGHT AND BEGIN TO MOVE SOUTH INTO THE RED
RIVER VALLEY. MEANWHILE A WELL DEFINED WARM SECTOR EXISTS FROM
NEAR SAN ANGELO NORTHWARD TO NEAR OKLAHOMA CITY AND BACK SOUTHEAST
INTO THE ARKLATEX. THERE IS ALSO ONE DISTINCT OUTFLOW BOUNDARY
WHICH IS NOW ALSO MOVING INTO THE ARKLATEX WITH SCATTERED
THUNDERSTORMS DEVELOPING ALONG IT. 20Z OBJECTIVE ANALYSIS
INDICATES A MODERATELY UNSTABLE AIRMASS IN PLACE ACROSS NORTH
TEXAS WITH SURFACE BASED CAPE AROUND 1500J/KG AND LITTLE
CONVECTIVE INHIBITION REMAINING ESPECIALLY ACROSS THE EASTERN HALF
OF THE CWA. TWO AMDAR VAPOR SOUNDINGS HOWEVER JUST CAME IN ABOUT
20 MINUTES AGO FROM DFW AIRPORT AND REVEALED THAT SUFFICIENT CONVECTIVE
INHIBITION REMAINS IN PLACE. THE FLIGHT PATHS CAME IN FROM THE
EAST WHERE THE CAP WAS OBSERVED SO THIS YIELDS HIGHER CONFIDENCE
THAT CAPPING REMAINS IN PLACE FARTHER EAST THAN INDICATED BY
OBJECTIVE ANALYSIS. A VEERED LOW LEVEL WIND PROFILE IS ALSO
REINFORCING A WARM LAYER ALOFT ESPECIALLY ACROSS THE WESTERN
COUNTIES THIS AFTERNOON.
SO WHAT HAPPENS... WITH THE LACK OF ANY APPRECIABLE LARGE SCALE
FORCING FOR ASCENT IN THE NEXT 6 HOURS IT APPEARS UNLIKELY THAT
THUNDERSTORMS WILL DEVELOP ACROSS NORTH TEXAS THROUGH THIS
EVENING. MESOSCALE FORCING ALONG THE OUTFLOW BOUNDARY TO THE EAST
IS MORE THAN SUFFICIENT FOR THUNDERSTORM DEVELOPMENT TO CONTINUE
IN THE ARKLATEX...AND WILL HAVE SOME 20 POPS ACROSS THE FAR
NORTHEAST TO ACCOUNT FOR THIS. OTHERWISE...IT APPEARS THAT WE WILL
HAVE TO WAIT UNTIL LATER TONIGHT FOR ADDITIONAL THUNDERSTORMS TO
AFFECT THE AREA. THE ONE CAVEAT TO THIS IS THE FAR WESTERN
COUNTIES. THE HIGH RES GUIDANCE AND TO A LESSER EXTENT THE GFS/NAM
ALL APPEAR TO ATTEMPT TO CONVECT BY 00Z THIS EVENING. THIS APPEARS
TO BE IN RESPONSE TO SURFACE HEATING WITH FORCING ALONG THE
DRYLINE. CONFIDENCE IN THIS SCENARIO IS LOW NOW GIVEN THE VEERED
LOW LEVEL WIND FIELDS AND A LACK OF SUBSTANTIAL CONVERGENCE. AFTER
00Z IT APPEARS THAT THE SURFACE WINDS MAY BACK MORE IN RESPONSE TO
UPSTREAM HEIGHT FALLS. THIS COULD LOCALLY ENHANCE CONVERGENCE
ACROSS THE WESTERN COUNTIES. IF ANYTHING WERE TO DEVELOP IN THIS
AREA IT WOULD LIKELY BE SEVERE.
THE MORE LIKELY SCENARIO FOR THUNDERSTORMS TONIGHT APPEARS TO BE
IN RESPONSE TO INCREASING FORCING FOR ASCENT AS A SHORTWAVE MOVES
THROUGH THE CENTRAL PLAINS AND HEIGHT FALLS OVERSPREAD THE REGION.
THE COLD FRONT ACROSS OKLAHOMA WILL BEGIN TO MOVE SOUTH AND
SCATTERED TO NUMEROUS THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG
IT. ADDITIONAL THUNDERSTORMS MAY DEVELOP AHEAD OF THE FRONT
EARLIER IN THE NIGHT ALONG A PRE-FRONTAL TROUGH WHERE CAPPING GETS
SUFFICIENTLY WEAKENED IN RESPONSE TO INCREASING LIFT. ALL OF THIS
IS LIKELY TO INITIATE ACROSS SOUTHERN OKLAHOMA AND MOVE SOUTH
ACROSS THE RED RIVER. THE BEST TIMING FOR THE INITIAL CONVECTIVE
DEVELOPMENT...IF IT CAN DEVELOP...APPEARS TO BE AROUND MIDNIGHT.
IF CONVECTION FAILS TO INITIATE ALONG THIS PRE-FRONTAL TROUGH THEN
THE MAIN SHOW SHOULD BE ALONG THE FRONT VERY LATE TONIGHT INTO
EARLY SUNDAY MORNING. THE ATMOSPHERE REMAINS MODERATELY UNSTABLE
WITH VERY STEEP LAPSE RATES SO THUNDERSTORMS WILL HAVE THE
POTENTIAL TO BE SEVERE. IF THE EARLIER ROUND OF STORMS CAN
DEVELOP...ITS SEVERE POTENTIAL WILL BE GREATER AS IT WILL HAVE AN
UNTAPPED RESERVOIR OF INSTABILITY TO WORK WITH. IT IS LIKELY THAT
THUNDERSTORMS THAT DEVELOP THAT LATE IN THE NIGHT WILL BE SLIGHTLY
ELEVATED...HOWEVER WITH 1500-2000J/KG OF MUCAPE AND 40-50KTS OF
DEEP LAYER SHEAR TO WORK WITH...ELEVATED SUPERCELLS ARE LIKELY.
LARGE HAIL WILL BE THE MAIN THREAT...ALTHOUGH DAMAGING WINDS CAN
EASILY MAKE IT TO THE GROUND DESPITE BEING SLIGHTLY ELEVATED. WILL
HAVE POPS INCREASING THROUGH THE NIGHT TONIGHT WITH HIGHEST
NUMBERS ALONG THE RED RIVER AND NORTHEAST COUNTIES.
ONE OR MORE CLUSTERS OF THUNDERSTORMS SHOULD BE ONGOING EARLY
EASTER MORNING ACROSS NORTH TEXAS. AS THE FRONT CONTINUES TO MOVE
SOUTH THE THUNDERSTORMS WILL GRADUALLY SHIFT SOUTH AS WELL THROUGH
THE DAY. BY AFTERNOON...THE ATMOSPHERE ACROSS THE SOUTHERN HALF OF
THE CWA WILL BE UNSTABLE AND SEVERE THUNDERSTORMS WILL BE POSSIBLE
ACROSS THE SOUTHERN COUNTIES. THESE WILL HAVE THE POTENTIAL TO
PRODUCE LARGE HAIL AND DAMAGING WINDS.
MONDAY APPEARS TO PROVIDE A BRIEF RESPITE FROM THE ACTIVE WEATHER
WITH THE OLD FRONTAL BOUNDARY TO THE SOUTH AND WEAK RIDGING ALOFT.
THE BREAK IS EXPECTED TO BE SHORT THOUGH AS A STRONG UPPER LOW
MOVES INTO THE 4-CORNERS REGION. THE STRONGER FRONT ASSOCIATED
WITH THIS SYSTEM WILL SLIDE SOUTH WITH STRONG ISENTROPIC ASCENT
COMMENCING MONDAY NIGHT. SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ARE EXPECTED LATE MONDAY NIGHT. BETTER RAIN CHANCES
ACROSS NORTH TEXAS WILL BE TUESDAY AND ESPECIALLY TUESDAY NIGHT AS
THE LOW SLOWLY MOVES EAST. WILL HAVE HIGH POPS ACROSS THE ENTIRE
CWA AS IT APPEARS VERY BENEFICIAL RAINFALL WILL OCCUR ACROSS THE
REGION. THUNDERSTORM ACTIVITY IS EXPECTED TO BE ELEVATED AND MORE
ISOLATED IN NATURE DURING THIS TIME...SO WIDESPREAD SEVERE WEATHER
IS NOT EXPECTED AT THIS TIME. DID WARM TEMPS UP A BIT THROUGH
MIDWEEK AS GUIDANCE IS NOT QUITE AS COLD WITH THE AIR COMING DOWN.
IT WILL STILL BE CHILLY WITH HIGHS IN THE UPPER 50S AND LOWER 60S.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 62 74 53 76 54 / 50 70 10 10 40
WACO, TX 65 76 58 77 59 / 20 60 20 10 40
PARIS, TX 58 72 52 75 47 / 60 80 10 10 20
DENTON, TX 61 74 53 77 50 / 60 70 10 10 50
MCKINNEY, TX 61 73 53 75 52 / 60 80 10 10 40
DALLAS, TX 64 76 55 78 56 / 50 70 20 10 40
TERRELL, TX 63 74 54 76 56 / 50 80 20 10 30
CORSICANA, TX 63 76 58 77 59 / 20 70 20 10 30
TEMPLE, TX 64 78 58 79 61 / 20 60 20 10 30
MINERAL WELLS, TX 60 75 53 79 52 / 40 50 10 10 50
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/82
AREA FORECAST DISCUSSION
NWS TAUNTON MA
713 AM EDT SUN MAR 31 2013
.SYNOPSIS...
AFTER A CHILLY START EARLY THIS MORNING...DRY AND MILD WEATHER IS
EXPECTED FOR THE AFTERNOON AS HIGH PRESSURE MOVES OFF THE COAST. A
COLD FRONT WILL BRING A PERIOD RAIN SHOWERS TO THE REGION
TONIGHT...AND PERHAPS AN EMBEDDED THUNDERSTORM OR TWO. A SECONDARY
COLD FRONT WILL LIKELY BRING A FEW SHOWERS TO THE REGION MON.
COOL AIR AND GUSTY WINDS ARE EXPECTED THROUGH MIDWEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
7 AM UPDATE...
ONLY MINOR ADJUSTMENTS TO THE FORECAST THIS MORNING. ADJUSTED
TIMING OF SKIES TOWARD LATEST RAP WHICH SEEMS TO BE HANDLING THE
CI DECK MOVING IN AHEAD OF AN OCCLUDED FRONT BETTER THAN MOST
AVAILABLE GUIDANCE. OTHERWISE...MUCH OF THE REST OF THE FORECAST
REMAINS ON TRACK. BROUGHT TEMPS AND DWPTS UP TO CURRENT TRENDS.
PREVIOUS DISCUSSION...
MOSTLY SUNNY SKIES FOR MUCH OF THE MORNING WILL GIVE WAY TO AN
INCREASE IN CLOUDINESS FROM THE WEST THIS AFTERNOON. THIS A RESULT
OF MID/HIGH LEVEL MOISTURE STREAMING OUT AHEAD OF AN APPROACHING
COLD FRONT. THE BEST DYNAMICS AND FORCING WILL REMAIN WELL TO OUR
WEST THROUGH THE AFTERNOON HOURS...SO EXPECT DRY WEATHER TO
PREVAIL TODAY.
ALTHOUGH ITS QUITE CHILLY VERY THIS MORNING...THE STRONG LATE MARCH
SUN ANGLE ALONG WITH A RELATIVELY DRY AIRMASS IN PLACE WILL ALLOW
FOR A QUICK RECOVERY. HIGH TEMPS SHOULD REACH INTO THE UPPER 50S TO
NEAR 60 ACROSS MANY LOCALES. IT WILL BE COOLER ALONG THE IMMEDIATE
SOUTH COAST WITH SOUTH TO SOUTHWEST WINDS BLOWING OFF THE COLD
OCEAN. IT MAY ALSO BE COOLER ON THE VERY IMMEDIATE EASTERN MA COAST
AS A RESULT OF LOCALIZED SEA BREEZES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
TONIGHT...
THE COLD FRONT WILL MOVE ACROSS THE REGION TONIGHT AS A
SECONDARY WAVE OF LOW PRESSURE DEVELOPS NEAR THE SOUTH COAST. THE
FRONT HAS FAIRLY GOOD DYNAMICS ALONG WITH DECENT MOISTURE...SO
EXPECT A BAND OF WIDESPREAD RAIN SHOWERS FOR SEVERAL HOURS. WHILE
THE RAIN SHOULD ONLY LAST FOR A 3 TO 5 HOUR PERIOD IN A GIVEN
LOCATION...IT MAY BE BRIEFLY HEAVY.
IN ADDITION...TOTAL TOTAL VALUES RISE INTO THE LOW TO MID 50S ALONG
WITH SHOWALTERS DROPPING CLOSE TO ZERO. THIS MAY BE JUST ENOUGH
ELEVATED INSTABILITY FOR A FEW EMBEDDED THUNDERSTORMS WITH THE BEST
CHANCE ALONG THE SOUTHEAST NEW ENGLAND COAST. WILL CONTINUE TO
CARRY ISOLATED THUNDER IN THE FORECAST TO COVER THIS POTENTIAL.
MONDAY...
THE RAIN SHOWERS WILL HAVE LONG SINCE EXITED THE COAST BY
DAYBREAK MONDAY. A FAIR AMOUNT OF SUN EARLY AND A MILD START SHOULD
ALLOW MUCH OF THE REGION TO SEE HIGHS RECOVER INTO THE UPPER 50S AND
LOWER 60S...ALTHOUGH IT WILL BE QUITE BREEZY. BY MON AFTERNOON...A
SECONDARY COLD FRONT AND A POTENT SHORTWAVE WILL SWING ACROSS THE
REGION. THIS LOOKS TO BE QUITE A DYNAMIC SETUP WITH STEEP MID LEVEL
LAPSE RATES APPROACHING 7 TO 7.5 C/KM. THERE PROBABLY WILL BE A FEW
HUNDRED J/KG OF SURFACE BASED CAPE ALONG WITH 100+ KNOT 250 MB JET.
EXPECT SCATTERED SHOWERS TO DEVELOP AND THEY MAY CONTAIN LOCALLY
GUSTY WINDS GIVEN DECENT TEMP/DEWPOINT SPREADS. HAVE ALSO INCLUDED
A SLIGHT CHANCE OF THUNDER GIVEN THE STEEP MID LEVEL LAPSE RATES AND
STRONG JET DYNAMICS. TEMPERATURES WILL FALL QUICKLY INTO THE UPPER
30S AND 40S BY EARLY MONDAY EVENING AS MUCH COLDER AIR WORKS INTO
THE REGION BEHIND THE FRONT.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
HIGHLIGHTS...
* GUSTY NORTHWEST WINDS TUE AND WED ESPECIALLY.
* TEMPERATURES SEASONABLY COOL THROUGH WED AS WELL.
* WILL HAVE TO WATCH COASTAL LOW FOR FRI.
OVERVIEW AND MODEL PREFERENCES...
31/00Z MODEL GUIDANCE SUITE CONTINUES TO BE IN FAIRLY GOOD
AGREEMENT REGARDING SYNOPTIC PATTERN THROUGH MUCH OF THE WEEK.
GREENLAND BLOCK REMAINS IN PLACE. THE BIGGEST DIFFERENCES REMAIN
WITH SRN STREAM ENERGY AND ITS SFC REFLECTION...A COASTAL LOW PRES
WHICH WILL PASS S OF THE REGION. THE TRACK IS WHAT REMAINS IN
QUESTION...AND IS LIKELY DEPENDENT ON THE CONTINUED GREENLAND
BLOCK THE GUIDANCE SHOWS IN PLACE. WILL NEED TO KEEP AN EYE ON
THIS...AS MODELS CONTINUE TO SWAP BACK AND FORTH AS TO WHETHER OR
NOT IT EFFECTS THIS REGION. WILL CONTINUE USING GFS/ECMWF AS A
BASELINE FOR MUCH OF THE FORECAST...BUT WILL LEAN CLOSE TO
PERSISTENCE WITH THE FRI LOW PASSAGE AS PREVIOUS FORECAST SCENARIO
SEEMS LIKE A GOOD STARTING POINT. ENSEMBLES ARE NOT MUCH HELP
HERE...SO CHANCE TO SLIGHT CHANCE POPS SEEM GOOD FOR THAT TIME
FRAME.
DETAILS...
TUE THRU THU...
MOSTLY DRY DURING THIS PERIOD AS SLOW MOVING HIGH PRES AND UPPER
LVL RIDGE GRADUALLY CREST OVER THE REGION. H85 TEMPS START ABOUT
-10C TUE SUPPORTING TEMPS IN THE LOW TO MID 40S...-8C ON WED
SUPPORTING TEMPS TOWARD THE UPPER 40S TO ABOUT -5C BY THU...SO
TEMPS IN THE LOW TO MID 50S ARE LIKELY TO RETURN. TIGHT PRES
GRADIENT WITH LOW LVL WINDS POSSIBLY MIXING TO 25-30KT AT
TIMES...SO SFC WIND GUSTS OF 20-30 MPH ARE NOT OUT OF THE QUESTION
ESPECIALLY TUE AND WED.
FRI INTO FRI NIGHT...
HIGH PRES SLIPS TO THE NE SETTING UP A POTENTIAL BLOCK...THE
LOCATION OF WHICH WILL HAVE FAIRLY SIGNIFICANT IMPACT ON THE FINAL
TRACK OF A COASTAL LOW PRES S AND E OF SRN NEW ENGLAND. LATEST GFS
AND SOME ECENS AND GEFS ENSEMBLE MEMBERS ARE NOW BRINGING THE THIS
JUST SE OF THE 40/70 BENCHMARK...WITH SOME PRECIPITATION SPREADING
FROM SRN CT NE TO ABOUT BOS. THIS SOLUTION IS ALSO A BIT
COLDER...WITH H85 TEMPS DIPPING BELOW 0C N OF THE CAPE COD
CANAL...WHICH SUGGEST SOME WET SNOW POSSIBLE IN THE INTERIOR
COASTAL PLAIN. HOWEVER...ECWMF AND MANY GEFS/ECENS MEMBERS ARE A
BIT FURTHER OFFSHORE AND WARMER. GIVEN THE DIFFERENCES HERE...WILL
CONTINUE TO ERR TOWARD POPS SUGGESTED BY PREVIOUS
FORECASTER...WHICH SUGGESTS CHANCE POPS ALONG THE IMMEDIATE COAST
AND SLIGHT CHANCE POPS UP TO ABOUT THE MASS PIKE AS THIS IS A GOOD
MIDDLE GROUND. THE TIMING DIFFERENCES SEEM TO BE COMING TOGETHER
WITH THE LATEST GFS SLOWING A BIT AND THE ECMWF SPEEDING UP
SOMEWHAT...SUGGESTING THE CLOSEST PASS IS NOW MORE LIKE FRI NIGHT.
IN TERMS OF THERMAL PROFILES WILL USE A 50-50 BLEND OF THE WARMER
ECMWF AND COLDER GFS FOR THE TIME BEING...WHICH STILL DOES
INTRODUCE AT LEAST THE POTENTIAL FOR A RAIN-SNOW MIX AWAY FROM THE
COAST DURING THE OVERNIGHT HOURS. HOWEVER...DURING THE DAY
FRI...BL TEMPS MAY PRECLUDE ANY SNOW CHANCES UNLESS A COLDER
NORTHERLY DRAW APPEARS LIKELY OR DYNAMIC COOLING IS ENOUGH TO
OVERCOME THIS TOWARD THE EVENING. A LOT OF PLAYERS STILL YET TO
COME IN LINE.
SAT...
GUIDANCE CONTINUES TO SUPPORT...AFTER ANY POTENTIAL PRECIP...THAT
HIGH PRES BUILDS IN FOR THE EARLY HALF OF THE WEEKEND. MOSTLY DRY
WEATHER AND TEMPS NEAR SEASONABLE LOOK REASONABLE GIVEN THE
THERMAL PROFILE.
SUN...
MODELS ARE ACTUALLY IN DECENT AGREEMENT THAT A FAST MOVING MID
LVL SHORTWAVE WILL PASS THROUGH THE ZONAL JET SET UP JUST TO THE N
OF THE AREA...HOWEVER THE SFC REFLECTION SPREAD IS QUITE BROAD.
WILL ERR TOWARD A MORE UNSETTLED SOLUTION FOR SUN.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...HIGH CONFIDENCE TODAY WITH MODERATE CONFIDENCE TONIGHT.
HIGH CONFIDENCE RETURNS ON MONDAY.
TODAY...HIGH CONFIDENCE IN VFR CONDITIONS. SOUTHERLY WIND GUSTS
AROUND 20 TO 25 KNOTS EXPECTED THIS AFTERNOON.
TONIGHT...MVFR CONDITIONS DEVELOP FROM WEST TO EAST WITH EVEN SOME
IFR CONDITIONS LIKELY FOR A TIME. THIS A RESULT FROM A BAND OF RAIN
SHOWERS WHICH MAY BE BRIEFLY HEAVY AHEAD OF AN APPROACHING COLD
FRONT. A FEW EMBEDDED THUNDERSTORMS ARE ALSO POSSIBLE WITH THE BEST
CHANCE ACROSS THE SOUTHEAST NEW ENGLAND COAST.
MONDAY...MAINLY VFR CONDITIONS EARLY IN THE DAY WITH GUSTY WEST
WINDS OF 25 TO 30 KNOTS. CAN/T RULE OUT SOME BRIEF MVFR CONDITIONS
ALONG WITH A COUPLE OF SHOWERS AS A SECONDARY COLD FRONT MOVES
THROUGH THE REGION.
KBOS TAF...HIGH CONFIDENCE IN VFR CONDITIONS TODAY. STILL
EXPECTING AN ESE SEABREEZE ESPECIALLY THIS MORNING. HIGH
CONFIDENCE IN AT LEAST A PERIOD OF MVFR CONDITIONS TONIGHT WITH
BRIEF IFR CONDITIONS ALSO POSSIBLE. THIS IN ASSOCIATION WITH A
BAND OF SHOWERS AND A LOW PROBABILITY OF AN ISOLATED THUNDERSTORM.
KBDL TAF...HIGH CONFIDENCE VFR CONDITIONS TODAY. HIGH CONFIDENCE IN
AT LEAST A PERIOD OF MVFR CONDITIONS TONIGHT WITH BRIEF IFR
CONDITIONS ALSO POSSIBLE. THIS IN ASSOCIATION WITH A BAND OF
SHOWERS AND A LOW PROBABILITY OF AN ISOLATED THUNDERSTORM.
OUTLOOK...MONDAY NIGHT THROUGH THURSDAY...
MONDAY NIGHT THROUGH THURSDAY...HIGH CONFIDENCE.
VFR. WEST TO NORTHWEST WINDS GUST TO AROUND 25 TO EVEN AN
ISOLATED 30 KNOTS TUESDAY AND WEDNESDAY.
&&
.MARINE...
TODAY...HIGH CONFIDENCE THAT WINDS/SEAS REMAIN BELOW SCA THRESHOLDS.
HOWEVER...SOUTHERLY WINDS MAY GUST TO 20 KNOTS THIS AFTERNOON AS
HIGH PRESSURE MOVES EAST OF THE REGION.
TONIGHT...HIGH CONFIDENCE IN A PERIOD OF SOUTH TO SOUTHEAST SCA WIND
GUSTS/SEAS ACROSS MOST OF OUR OPEN WATERS. PREVIOUS SCA HEADLINES
FOR ALL OPEN WATERS CONTINUES. THIS A RESULT OF AN INCREASING
PRESSURE GRADIENT AHEAD OF AN APPROACHING COLD FRONT AND WAVE OF LOW
PRESSURE. A BAND OF RAIN SHOWERS WILL ACCOMPANY THE FRONT AND CAN/T
RULE OUT A FEW ISOLATED THUNDERSTORMS ESPECIALLY ACROSS THE
SOUTHEAST WATERS.
MONDAY...HIGH CONFIDENCE IN SCA WIND GUSTS OF 25 TO 30 KNOTS ACROSS
THE WATERS ESPECIALLY NEAR SHORE WITH EXCELLENT MIXING. HAVE
EXTENDED SCA FOR ALL OPEN WATERS THROUGH MON AFTERNOON. LATER
SHIFTS WILL ALSO PROBABLY NEED TO ISSUE SCA FOR BOSTON HARBOR AND
NARR BAY...BUT SINCE ITS WAS 3RD PERIOD HELD OFF ON IT ON THIS
SHIFT.
OUTLOOK...MONDAY NIGHT THROUGH THURSDAY...
MODERATE TO HIGH CONFIDENCE.
MONDAY THROUGH WEDNESDAY...
PROLONGED PERIOD WITH NW WIND GUSTS 25 TO 30 KT POSSIBLE. LOW
PROBABILITY OF AN OCCASIONAL GALE FORCE GUST. SEAS WILL BE 5-7 FT
ON OUTER WATERS. SMALL CRAFT ADVISORIES WILL BE NEEDED.
THURSDAY...DIMINISHING WINDS AND SEAS. SMALL CRAFT HEADLINES MAY
LINGER ON THE OUTER WATERS DURING THE MORNING.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 PM EDT MONDAY
FOR ANZ231>235-237-250-254>256.
SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 8 PM EDT
MONDAY FOR ANZ251.
&&
$$
SYNOPSIS...FRANK/DOODY
NEAR TERM...FRANK/DOODY
SHORT TERM...FRANK
LONG TERM...DOODY
AVIATION...FRANK/DOODY
MARINE...FRANK/DOODY
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1022 AM EDT SUN MAR 31 2013
.UPDATE...
A FEW SHOWERS LINGER OVER TOOMBS COUNTY BUT THESE ARE MOVING QUICKLY
TO THE EAST. AN AREA OF SHOWERS AND ISOLATED TSTORMS OVER CENTRAL AL
IS HOLDING TOGETHER AND SHOULD MOVE INTO WEST CENTRAL GA AROUND
NOON. MODELS NOT HANDLING THIS AS WELL...ALTHOUGH THE HRRR DOES HAVE
THE AREA OF SHOWERS BUT TOO FAR NORTH. THE 2ND WAVE OVER OK/AR STILL
PROGGED TO MOVE INTO THE CWA LATE THIS AFTERNOON/THIS EVENING. TEMPS
STILL LOOK ON TARGET. EVEN WITH THE CLOUDS THERE IS STILL SOME GOOD
WAA TODAY. OTHER THAN ADJUSTING THE POPS...NO OTHER CHANGES PLANNED.
&&
.SHORT TERM /TODAY THROUGH MONDAY/...
/ISSUED AT 740 AM EDT SUN MAR 31 2013/
SHORT WAVE CURRENTLY MOVING THROUGH OHIO/TN VALLEY AREA. SHOWERS
ASSOCIATED WITH THIS FEATURE WILL CONTINUE TO MOVE EAST THROUGH THE
CWA THIS MORNING. SHOWERS SHOULD DIMINISH THROUGH THE MORNING AND
MODELS INDICATE A BREAK BETWEEN THIS WAVE AND THE NEXT ONE WHICH
SHOULD AFFECT US STARTING THIS AFTERNOON. HAVE INCREASED POPS AGAIN
STARTING AROUND 18Z AND CONTINUE WITH LIKELY POPS FOR MUCH OF THE
CWA THROUGH 06Z MONDAY. INSTABILITY INCREASES ALSO DURING THIS
AFTERNOON WITH BEST CAPE AND LIFTED INDEX VALUES 18Z TODAY THROUGH
06Z MONDAY. HAVE CONTINUED WITH MENTION OF THUNDER DURING THAT TIME.
UPPER TROUGH DEEPENING OVER THE NORTHERN STATES SHOULD PUSH A
SURFACE BOUNDARY INTO NORTH GA LATE TONIGHT AND INTO MONDAY. SOME
DRYING SHOULD OCCUR BEHIND THIS BOUNDARY AND HAVE ENDED SHOWERS FROM
THE NORTH MONDAY MORNING WITH SOME POPS CONTINUING THROUGH THE
CENTRAL ZONES INTO THE AFTERNOON. TEMPERATURES CONTINUE WARM THROUGH
THE SHORT TERM AND HAVE TAKEN A BLEND OF THE MAV/MET.
41
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
/ISSUED AT 740 AM EDT SUN MAR 31 2013/
NEXT MAIN RAIN EVENT WILL ENCOMPASS THE SECOND HALF OF THE WEEK.
GFS/EUROPEAN SIMILAR WITH BRINGING RAIN TO THE AREA POSSIBLY AS
EARLY AS TUESDAY NIGHT/WEDNESDAY BUT MORE SO WEDNESDAY NIGHT INTO
FRIDAY. A WARM FRONT DEVELOPS ALONG THE GULF COAST WITH OVERRUNNING
MOIST FLOW SETTING UP. THE MAIN DIFFERENCE BETWEEN THE GFS AND
EUROPEAN IS THE EUROPEAN BRINGS SURFACE LOW PRESSURE ACROSS CENTRAL
TO S GA THURSDAY NIGHT AND FRIDAY WHILE THE GFS TAKES THE SURFACE
LOW ACROSS N FL. GFS BRINGS ONLY MINIMAL MUCAPE INTO CENTRAL GA
THURSDAY/THURSDAY NIGHT. IF THE EUROPEAN SURFACE SOLUTION COMES TO
PASS THE CHANCES FOR THUNDERSTORMS WOULD BE GREATER WITH THE WARM
FRONT POSSIBLY GETTING INTO CENTRAL GA WITH A LOW END THREAT FOR
SEVERE WEATHER. EITHER WAY A GOOD RAIN EVENT WITH 1 TO 2 INCHES
ACROSS CENTRAL GA. THE UPPER TROUGH MOVES TO THE AREA FRIDAY
WITH THE GFS A LITTLE FASTER WITH THE TROUGH AND MOISTURE EXITING
THAN THE EUROPEAN. A DAMPENING SHORT WAVE RIDGE AND SURFACE HIGH
PRESSURE MOVE TO THE AREA SATURDAY WITH DRY CONDITIONS EXPECTED
AND THIS LOOKS TO CONTINUE FOR SUNDAY.
BDL
&&
.AVIATION...
12Z UPDATE...
SEVERAL WAVES OF LOW PRESSURE WILL MOVE EAST ALONG A STALLED
FRONT THROUGH SUNDAY....BRINGING ROUNDS OF SHOWERS ACROSS THE
FORECAST AREA. EXPECT VARIABLE CEILINGS THROUGH THE REMAINDER OF THE
MORNING WITH SOME AREAS OF IFR UNTIL 14Z. CEILINGS IMPROVING TO VFR
AFTER 14Z BUT SHOWERS AND A FEW THUNDERSTORMS DEVELOPING AGAIN BY
18Z AND CONTINUING INTO THE EVENING. WINDS SOUTHWEST 10KT WITH SOME
GUSTS TO NEAR 18Z MAINLY AFTER 18Z.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE ALL ELEMENTS.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 53 75 46 / 40 60 10 10
ATLANTA 70 54 73 50 / 50 60 10 10
BLAIRSVILLE 63 47 69 39 / 50 60 10 20
CARTERSVILLE 69 50 72 43 / 60 60 10 10
COLUMBUS 76 58 77 52 / 50 70 30 5
GAINESVILLE 69 51 74 47 / 40 60 10 10
MACON 76 57 77 48 / 40 70 30 5
ROME 70 50 73 43 / 60 60 10 20
PEACHTREE CITY 71 52 74 45 / 50 60 10 5
VIDALIA 78 60 77 53 / 30 70 60 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...41
LONG TERM....BDL
AVIATION...41
AREA FORECAST DISCUSSION
NWS PADUCAH KY
702 AM CDT SUN MAR 31 2013
.UPDATE...
ISSUED AT 701 AM CDT SUN MAR 31 2013
LATEST RADAR TRENDS SHOW ANY THUNDER THREAT GETTING SHUNTED TO OUR
WEST AND SOUTHWEST. THE FRESHEST DEVELOPMENT IS IN NORTHERN
ARKANSAS...WHICH MAY SPELL A RAPID END TO THE MISSOURI CONVECTION
EARLY THIS MORNING. SOME SHORT TERM GUIDANCE PUSHES THE NORTHERN
ARKANSAS CONVECTION MORE TO THE EAST...POTENTIALLY IMPACTING OUR
ENTIRE SOUTHERN BORDER WITH TIME THROUGH THE DAY.
BEST GUESS IS THAT AREAS ALONG AND WEST OF A LINE FROM MARBLE HILL
MISSOURI TO FULTON KENTUCKY LINE COULD SEE SOME TANGIBLE SHOWERS
THIS MORNING. UPDATED TO BRING CHANCE POPS SOUTHEAST ACROSS THIS
AREA THROUGH THE MORNING. AREAS NEAR THE TENNESSEE BORDER COULD
SEE A STRAY SHOWER EARLY THIS AFTERNOON.
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 12Z TAF ISSUANCE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 406 AM CDT SUN MAR 31 2013
CONSIDERED A DENSE FOG ADVISORY FOR WESTERN PORTIONS OF SOUTHEAST
MISSOURI DUE TO KPOF REPORTING 1/2 MILE OR LESS...BUT IT SEEMS TO
BE IMPROVING A BIT IN THE LAST HOUR AND WE HAVE LITTLE CLUE HOW
WIDESPREAD IT IS. WILL KEEP AN EYE ON IT...BUT FOR NOW WILL JUST
LET IT BE.
WEAK ECHOES FOR LIGHT RAIN HAVE JUST ABOUT PUSHED EAST OF THE
EVANSVILLE TRI STATE...BUT THERE MAY BE JUST A BIT LINGERING IN
THE KOWB AREA. THIS SHOULD COME TO AN END SHORTLY. OF GREATER
CONCERN IS THE AREA OF SHOWERS AND THUNDERSTORMS MOVING EAST
SOUTHEAST ACROSS EASTERN KANSAS AND WEST CENTRAL MISSOURI.
HAD TO LEAN ON THE HRRR MODEL SIMULATED REFLECTIVITY TO REPRESENT
THIS IN THE GRIDS. IN GENERAL WOULD EXPECT THE AREA TO WEAKEN AS
IT MOVES INTO OUR REGION JUST AFTER SUNRISE...SO WILL HAVE 20-30
POPS FOR NOW...GENERALLY SWEEPING ACROSS OUR SOUTHWEST HALF 14Z-
20Z. THIS WEAKENING TREND IS SUPPORTED BY THE 06Z NAM...WHICH
KEEPS ANY INSTABILITY TO OUR WEST AND SOUTHWEST. WILL HAVE TO KEEP
A CLOSE EYE ON THIS SITUATION AS WELL AND BE PREPARED TO UPDATE
IF/WHEN IT BECOMES NECESSARY.
TEMPERATURES EARLY THIS MORNING ARE NEARLY STEADY...SO WE WILL
HAVE A MILD START TO THE DAY...WHICH IS GOOD BECAUSE THE LOW
CLOUDS/FOG AND EVENTUALLY SOME SHOWERS WILL DELAY WARMING THROUGH
THE MORNING. TRIED TO CAPTURE THIS TREND IN THE TEMPERATURE
GRIDS...BUT WE SHOULD JUMP UP WELL INTO THE 60S WITH SOME SUNSHINE
THIS AFTERNOON. STAYED CLOSE TO CONSENSUS.
LIKE THE 00Z AND 06Z NAM WITH THE REAL COLD FRONT/SURFACE HIGH
SURGE THROUGH THE AREA LATE TONIGHT AND MONDAY...AS IT SHOULD
HANDLE THE SHALLOW COLD AIRMASS BETTER THAN THE LESSER RESOLVED
GFS. THE NAM DOES GENERATE SOME VERY MEAGER QPF OVER THE
EVANSVILLE TRI STATE TONIGHT WITH THE INITIAL WIND SHIFT...BUT THE
GFS IS DRY. DECIDED TO MENTION SOME SPRINKLES IN THAT AREA THROUGH
THE NIGHT...BUT DID NOT INTRODUCE A MEASURABLE POP. CONSENSUS OF
GUIDANCE SEEMS TO HAVE A GOOD HANDLE ON TEMPERATURES TONIGHT.
TEMPERATURES ONLY FALL INTO THE UPPER 30S IN THE NORTH...SO LITTLE
CHANCE OF FLURRIES WITH THE SPRINKLES TONIGHT.
FOR MONDAY...THE MODELS CONTINUE TO TREND DRIER AND DRIER FOR OUR
AREA. SIMILAR TO TONIGHT...DECIDED TO JUST PLASTER A CHANCE OF
SPRINKLES ACROSS THE ENTIRE AREA THROUGH THE DAY...IN LIEU OF A
VERY SMALL MEASURABLE POP. TEMPERATURES WILL SUPPORT ALL LIQUID
THROUGH THE DAY. FIGURE WITH THE SURGE CONSISTENTLY ADVERTISED IN
THE NAM RUNS...THAT TEMPERATURES WILL BE COOLER THAN MOST GUIDANCE
INDICATES. STAYED ON THE LOW SIDE OF GUIDANCE CLOSER TO THE
NAM/MET...BUT THAT MAY NOT BE COOL ENOUGH.
MONDAY NIGHT WILL BE DRY...BUT WE WILL REMAIN IN CYCLONIC WEST
NORTHWEST FLOW ALOFT...SO CANNOT RULE OUT SOME LIGHT
PRECIPITATION...ESPECIALLY OVER OUR SOUTHWEST MONDAY NIGHT INTO
TUESDAY. THE GFS IS THE MOST AGGRESSIVE IN GENERATING LIGHT QPF
WITH SOME FRONTOGENETIC FORCING IN THE 850-700MB LAYER IN THE FAR
SOUTHWEST. INTRODUCED SOME VERY SMALL POPS NEAR THE ARKANSAS
BORDER AND THE BOOT HEEL REGION JUST TO BE SAFE. LATELY...IF THERE
IS ANY CHANCE OF US GETTING WET IT SEEMS TO HAPPEN. TEMPERATURES
IN THAT AREA SHOULD BE NO LOWER THAN THE MIDDLE 30S...SO KEPT THIS
ALL RAIN AS WELL. CONSENSUS TEMPERATURES LOOKED FINE MONDAY NIGHT
AND TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 406 AM CDT SUN MAR 31 2013
THIS EXTENDED PERIOD FOR THIS FORECAST ISSUANCE WILL SERVE AS THE
TRANSITION OF EXTREMES IN TEMPERATURE FROM NEAR RECORD LOWS
WEDNESDAY MORNING TO ABOVE NORMAL /MIDDLE 60S/ HIGHS NEXT WEEKEND.
GIVEN THE BELOW NORMAL TEMPERATURES WE HAVE BEEN EXPERIENCING IN
MARCH...TEMPERATURES AT OR ABOVE NORMAL WILL BE A WELCOME CHANGE.
THE ONLY WEATHER MAKER OF CONSEQUENCE WILL OCCUR THURSDAY/THURSDAY
NIGHT. ANY MEASURABLE POPS AND WEATHER /GENERALLY SLIGHT IN
CATEGORY/ WILL BE LIMITED TO WEST KENTUCKY AND A SMALL PART OF THE
SOUTHEAST MISSOURI BOOTHILL. THE SOURCE REGION FOR THIS SYSTEM IS
THE CLOSED LOW CURRENTLY OFF THE CALIFORNIA COAST. THIS FEATURE IS
EXPECTED TO PUSH TOWARD THE CENTRAL ROCKIES AND DIVE EAST-SOUTHEAST
INTO THE LOWER MISSISSIPPI VALLEY. DURING THE PAST 3-4 DAYS...THE
NORTHERN EDGE OF THIS CLOSED LOW/WAVE HAS BEEN FORECAST BY THE
GFS/ECMWF/GEM GUIDANCE TO SKIRT ALONG THE SOUTHERN BORDER OF THE WFO
PAH FORECAST AREA. THERE HAS BEEN ENOUGH MODEL RUNS TO STILL
INDICATE THAT VERY FEW LOCATIONS WILL SEE ANY RAIN...IF ANY...ON
THURSDAY. THE MAIN IMPACT WILL BE CLOUD COVER...WITH A SHARP
DEMARCATION LINE ON THE NORTHERN EDGE OF THE DEFORMATION ZONE
ASSOCIATED WITH THE LOW/WAVE. NORTHEAST WINDS DURING THIS TIME
PERIOD MAY TEMPER HIGHS SOMEWHAT.
WITH HIGH PRESSURE DOMINATING THE REGION THROUGH MOST OF THE
PERIOD...CLOUD COVER WILL BE MINIMAL OUTSIDE OF THE DISTURBANCE ON
THURSDAY. THIS WILL SET THE STAGE FOR GOOD INSOLATION/DRY AIR
ADVECTION AND EVAPORATION. A MANUAL UPWARD ADJUSTMENT WAS MADE TO
THE MAX TEMPERATURES FROM FRIDAY THROUGH SUNDAY TO ACCOUNT FOR A
LARGER DIURNAL RANGE /25-27 DEGREES F/IN TEMPERATURES WITH THE DRIER
AIR IN PLACE ACROSS THE WFO PAH FORECAST AREA.
AS A SIDE NOTE...MIN FORECAST TEMPERATURES WEDNESDAY MORNING LOOK
LIKE THEY MAY BE ONE TO TWO DEGREES HIGHER THAN THE RECORD
TEMPERATURES ON THE BOOKS. SUBTLE MICRO-CLIMATE CHANGES AROUND THE
OBSERVATION SITES WILL DETERMINE WHETHER ANY RECORDS ARE TIED OR SET
WEDNESDAY MORNING.
&&
.AVIATION...
ISSUED AT 701 AM CDT SUN MAR 31 2013
IFR CONDITIONS TO BEGIN WITH WILL DISSIPATE IN FAVOR OF VFR
CEILINGS AS A BAND OF CLOUDS FROM 1500 FT TO 6KFT MOVES ACROSS THE
ENTIRE AREA THIS MORNING. COULD SEE SOME SPRINKLES OUT OF THESE
CLOUDS AS THEY PASS OVER KCGI AND KPAH.
WINDS WILL BE HIGHLY VARIABLE IN SPACE AND TIME TODAY...BUT THEY
WILL GENERALLY BE LIGHT. SHOULD SEE A LIGHT SOUTH SOUTHEAST WIND
DEVELOP BY SUNSET...AS A SIGNIFICANT COLD FRONT APPROACHES. THE
FRONT WILL PUSH SOUTH THROUGH THE AREA OVERNIGHT. KEPT NORTH POST
FRONTAL WINDS RATHER LIGHT...AS THE MORE SIGNIFICANT SURFACE
PRESSURE SURGE WILL BE DELAYED A FEW HOURS. NOT LOOKING FOR ANY
CEILINGS OTHER THAN VFR BEYOND THIS MORNING.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...DRS
LONG TERM...SMITH
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
928 AM EDT SUN MAR 31 2013
.SYNOPSIS...
A CROSSING FRONT WILL BRING RAIN ON SUNDAY AND USHER IN COLD TEMPERATURES
FOR MUCH OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FOR THIS MORNINGS UPDATE...ONLY MADE SOME SLIGHT TIMING CHANGES TO
THE POPS AND TEMPERATURES BASED OFF OF THE MOST RECENT RADAR
COVERAGE AND HI RES MODEL TRENDS. THE HRRR AND THE RUC CONTINUE TO
SUGGEST...AS THE MID-SHIFT DISCUSSED BELOW...THAT THE GREATEST
SYNOPTIC LIFT AND QPF WILL REMAIN OVER MUCH OF THE SOUTHEASTERN
HALF OF OUR ZONES TODAY. THE ONLY THING TO NOTE: THE HRRR MAY BE
JUST A BIT SLOW ON IT`S COLD FRONT TIMING...AS IT IS ALREADY
MAKING IT INTO WESTERN OHIO. WILL CONTINUE TO MONITOR THE FRONTAL
TIMING AND ADJUST AS NECESSARY. OTHERWISE...LEFT FORECAST AS IS
FOR NOW.
PREVIOUS DISCUSSION FOLLOWS...
TODAY`S SYSTEM LOOKS TO START TO BRING LIFT INTO THE SOUTHWESTERN
PORTIONS OF THE AREA SHORTLY AFTER SUN UP...WITH THE CONSENSUS OF
THE TRACK OF STRONGEST LIFT AND HENCE QPF ACROSS THE SOUTHEASTERN
HALF OF THE FORECAST AREA THROUGH THE DAY. POPS AND QPF WERE
ADJUSTED FOR A LATER ONSET AS WELL AS TO FOCUS ON THE SOUTHEASTERN
ZONES. ALSO OF NOTE IS THAT THE INSTABILITY THAT THE NAM HAD
INDICATED OVER THE AREA ON YESTERDAY`S 00Z RUNS HAS BASICALLY
DISAPPEARED WITH THIS CYCLE. WHILE SOME POSITIVE AREA IS
NOTED...IT IS GENERALLY WELL BELOW THE LAYER IN WHICH IT WOULD BE
REQUIRED FOR CHARGE SEPARATION. ADDITIONALLY...SINCE THE BULK OF
THE SYNOPTIC LIFT TRAVERSES AREAS TO THE SOUTH OF US...STRONG LIFT
REALLY IS LACKING. WHILE RAIN SHOWERS ARE PRETTY MUCH A FOREGONE
CONCLUSION...THUNDERSTORMS STILL SEEM QUITE UNLIKELY TODAY.
TEMPERATURES WERE ADJUSTED GENERALLY DOWNWARD SLIGHTLY.
SIGNIFICANT CLOUD COVER COMBINED WITH DEVELOPING RAINFALL SHOULD
MANAGE TO RESTRICT OUR DIURNAL RISES SLIGHTLY...HOWEVER HIGHS NEAR
NORMAL IN THE 50S ARE STILL EXPECTED. FRIES
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
THE INITIAL COLD FRONT IS EXPECTED TO BE EAST OF THE REGION
TONIGHT. ADDITIONALLY...A SECONDARY COLD FRONT LARGELY STACKED IN
THE 850-500 MB LAYER LOOKS TO MOVE INTO THE AREA BY LATE TONIGHT.
THAT WILL BRING BOTH A SECONDARY SHOT OF COLDER AIR AS WELL AS A
SECONDARY SHOT AT FRONTOGENETICAL LIFTING. WHILE QPF VALUES WITH
THIS FRONT WILL LIKELY BE QUITE LIGHT...POPS WERE INCREASED FOR LOW
END QPF AND A RAIN TO SNOW SHOWER TRANSITION AS IT MOVES FROM
NORTHWEST TO SOUTHEAST ACROSS THE AREA THROUGH MONDAY.
THE MODEL CONSENSUS HAS REALLY CONVERGED ON BRINGING MUCH DRIER AIR
INTO THE AREA BEHIND THE SECONDARY FRONT. SO WHILE SHOWERS ARE
LIKELY TO TRANSITION TO SNOW...THEY SHOULD NOT PERSIST LONG BEHIND
THE PASSAGE. DEWPOINTS FROM BOTH EXPLICIT...ENSEMBLE...AND MOS
SOURCES DROP TOWARD 10F BY MID-WEEK...SO POPS WERE ESSENTIALLY
REMOVED FROM THE FORECAST. HOWEVER...WITH DRY AIR MOVING
IN BRINGING CLEAR SKIES...OVERNIGHT LOW WERE TRIMMED A FEW
DEGREES...AND MAY LIKELY STILL BE TOO WARM. FRIES
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
MODEL AND ENSEMBLE SOLUTIONS ALL FAVOR A DRY EXTENDED FORECAST. A
WEAK SYSTEM LOOK SUPPRESSED TO OUR SOUTH IN THE SPLIT FLOW PATTERN
LATE IN THE WEEK...WITH OPERATIONAL GUIDANCE FAVORING A TRACK INTO
THE D.C. REGION. WHILE SOME OF THIS MAY CLIP THE SOUTHEASTERN
PORTIONS OF THE FORECAST AREA...THE PREPONDERANCE OF THE PAST
SEVERAL MODEL CYCLES SUGGESTS THAT IT SHOULD REMAIN LARGELY TO OUR
SOUTHEAST. AS SUCH...THE ENTIRE EXTENDED FORECAST LOOKS FAIRLY DRY
FOR THE MOMENT.
TEMPERATURES THROUGH THE EXTENDED MODERATE TOWARD NORMAL. WITH A
SPLIT FLOW LIKELY TO BE IN PLACE...OUR AREA SHOULD REMAIN LARGELY
LOCKED BETWEEN THE NORTHERN AND SOUTHERN STREAM. AS A RESULT...NO
WILD SWINGS ABOVE OR BELOW NORMAL ARE EXPECTED AT THIS TIME. FRIES
&&
.AVIATION /13Z SUNDAY THROUGH THURSDAY/...
A GENERAL VFR FORECAST IS EXPECTED THROUGH MOST OF THE FORECAST
PERIOD. THERE WILL BE PERIODS OF TEMPO MVFR RESTRICTIONS WITH
SHOWERS BEGINNING DURING THE LATE MORNING HOURS AND CONTINUING
THROUGH MOST OF THE AFTERNOON. LATER FORECASTS CAN BETTER ADDRESS
THE TIMING OF THE RESTRICTIONS. LIGHT AND VARIABLE WINDS WILL VEER
TO THE SOUTH-SOUTHWEST AND INCREASE TO 10KTS. HIGHER GUSTS ARE
POSSIBLE IN THE AFTERNOON AT ZZV.
.OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/...
RAIN SHOWERS WILL BECOME MORE SCT AND ISO SUNDAY NIGHT AND MONDAY
AND MAY MIX WITH OR CHANGE OVER TO SNOW SHOWERS AS COLD NORTHWEST
FLOW DEVELOPS BEHIND THE FRONT. A FEW RESTRICTIONS ARE POSSIBLE IN
THE SCATTERED SNOW SHOWERS THROUGH MONDAY. SOME FLURRIES MAY
CONTINUE INTO TUESDAY MORNING BUT GENERAL VFR CONDITIONS CAN BE
EXPECTED THROUGH THURSDAY AS HIGH PRESSURE BUILDS OVR THE REGION.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1000 AM EDT SUN MAR 31 2013
.SYNOPSIS...
ISSUED AT 330 AM EDT SUN MAR 31 2013
TEMPERATURES WILL AVERAGE NEAR NORMAL TODAY BEFORE ANOTHER ROUND OF
UNSEASONABLY COLD AIR MOVES IN TONIGHT THROUGH TUESDAY. TEMPERATURES
WILL AVERAGE TEN TO FIFTEEN DEGREES BELOW NORMAL MONDAY THROUGH
TUESDAY WITH A FEW LIGHT LAKE EFFECT SNOW SHOWERS AND FLURRIES FROM
THE EARLY MORNING HOURS MONDAY THROUGH TUESDAY MORNING. TEMPERATURES
WILL MODERATE MID TO LATE WEEK AND RETURN TO NEAR NORMAL BY THURSDAY
AND FRIDAY. DRY WEATHER IS ANTICIPATED MID TO LATE WEEK AS HIGH
PRESSURE BUILDS IN.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY AFTERNOON)
ISSUED AT 1000 AM EDT SUN MAR 31 2013
LOOKING AT A FAIR AMOUNT OF EARLY AFTERNOON SUNSHINE AS LOW LEVEL
MOISTURE MIXES OUT THIS MORNING. STILL LOOKING AT EARLY AFTERNOON
TEMPS RANDING FROM THE UPPER 40S AT THE COAST TO MID 50S INLAND.
ALSO LIKE HI RES GUIDANCE SUGGESTING A COUPLE BANDS OF LIGHT SHRA /
SPRINKLES SPREADING WEST TO EAST AFTER 5PM. SHRA ACTIVITY WILL BE
ALONG AND AHEAD OF LEADING EDGE OF ARCTIC AIR.
EXPECT WESTERLY WIND GUSTS TO 30 MPH INLAND THIS AFTERNOON WITH
INITAL CAA AND MIXING. INITIALLY...STABLE TEMPERATURE STRATIFICATION
OVER THE LAKE WILL INHIBIT GUSTINESS. A SECOND ROUND OF WIND GUSTS
TO 35 MPH WILL AFFECT ALL AREAS AS THE ARCTIC AIR MOVES IN EARLY
THIS EVENING.
SCATTERED WNW FLOW LIGHT LAKE EFFECT SNOW SHOWERS AND FLURRIES WILL
DEVELOP VERY LATE TONIGHT AND CONTINUE MONDAY AS H8 TEMPS FALL TO
-13 TO -15 C BY 12Z MON. HOWEVER WITH A VERY DRY AIRMASS ADVECTING
IN AND LACK OF BETTER MOISTURE OR UPSTREAM RH THIS WILL NOT AMOUNT
TO ANYTHING (TRACE AMOUNTS TO JUST A FEW TENTHS OF AN INCH OF SNOW
FROM THE EARLY MORNING HOURS MONDAY THROUGH EARLY TUESDAY).
ANY LINGERING FLURRIES EARLY TUESDAY SHOULD END WITH AN EVEN DRIER
AIRMASS IN PLACE LATER ON TUESDAY AND AS H8 TEMPS BEGIN TO MODERATE
A BIT BY TUESDAY AFTN.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 AM EDT SUN MAR 31 2013
AFTER THE EARLY WEEK COLD BLAST... IT LOOKS LIKE WINTER WILL LOOSEN
ITS GRIP ON THE GREAT LAKES REGION. MEDIUM RANGE GUIDANCE IS
STARTING TO SHOW SOME CONSISTENCY THAT THE TROUGHING WHICH HAS
PERSISTED MOST OF MARCH OVER THE ERN U.S. WILL FINALLY LIFT OUT.
FOR THE MID TO LATE WEEK PERIOD THE UPPER FLOW WILL BE ZONAL WHICH
IMPLIES UNEVENTFUL WEATHER WITH TEMPERATURES MODERATING TO CLOSER TO
NORMAL VALUES. HOWEVER THERE ARE SIGNS THAT AN UPPER RIDGE WILL
BEGIN TO BUILD OVER THE REGION ABOUT A WEEK FROM NOW AS A DEEP
LONGWAVE TROUGH EVOLVES OVER THE WRN UNITED STATES. THIS IMPLIES
THAT ABOVE NORMAL TEMPERATURES WILL DEVELOP BEYOND DAY 7.
SFC HIGH PRESSURE WEDNESDAY AND THURSDAY OUGHT TO LEAD TO ABUNDANT
SUNSHINE ALTHOUGH RATHER CHILLY NIGHTTIME TEMPERATURES. A WEAK SFC
BOUNDARY DOES DROP SOUTH THROUGH THE REGION ON THURSDAY NIGHT BUT NO
PRECIP IS EXPECTED AS THERE IS LITTLE MOISTURE TO WORK WITH.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 752 AM EDT SUN MAR 31 2013
IFR CONDITIONS HAVE SETTLED INTO WRN LWR MI BEHIND THE SFC FRONT
WHICH AT 1130Z WAS ORIENTED NORTH-SOUTH ALONG ROUGHLY THE HIGHWAY
131 CORRIDOR. THE IFR CONDITIONS IN LOW CIGS AND MIST ARE EXPECTED
TO LINGER THROUGH MID TO LATE MORNING BEFORE LIFTING AS SFC WINDS
INCREASE OUT OF THE WEST AND BECOME GUSTY.
PRIMARILY VFR IS EXPECTED AFTER 18Z AS THE MORNING STRATUS SHOULD
HAVE TRANSITIONED INTO A CUMULUS DECK WITH HIGHER BASES. SOME
ADDITIONAL ISOLATED RAIN SHOWERS MAY DEVELOP THIS AFTERNOON BUT
LEFT THEM OUT OF THE TAFS SINCE VSBY RESTRICTIONS ARE UNLIKELY AND
COVERAGE SHOULD BE LIMITED.
&&
.MARINE...
ISSUED AT 1000 AM EDT SUN MAR 31 2013
BASED ON LATEST 3KM HRRR GUIDANCE...SMALL CRAFT CONDITIONS WILL
DEVELOP AROUND 00Z (8PM EDT) THIS EVENING...A BIT EARLIER THAN FIRST
EXPECTED. WIND GUSTS AROUND 30 KTS WITH SEAS BUILDING 5 TO 7 FEET
STILL LOOKING GOOD. VISIBILITY WILL OCCASIONALLY DROP BELOW 1 MILE
IN LAKE EFFECT SNOW SHOWERS OVERNIGHT THROUGH MONDAY. HIGH PRESSURE
WILL BRING FAIR WEATHER AND LIGHT WINDS FOR LATE TUESDAY THROUGH
THURSDAY.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT SUN MAR 31 2013
NO HYDRO ISSUES EXPECTED. RIVERS ARE ALL WELL BELOW ACTION STAGE AND
WILL REMAIN SO THROUGH THE WEEK. THE OVERALL WEATHER PATTERN THIS
WEEK WILL BE CONDUCIVE TO A GRADUAL MELTING AND RUNOFF OF REMAINING
SNOW COVER.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 PM EDT
TUESDAY
FOR LMZ844>849.
&&
$$
SYNOPSIS...LAURENS
SHORT TERM...COBB
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...LAURENS
MARINE...COBB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
746 AM EDT SUN MAR 31 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 544 AM EDT SUN MAR 31 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A DEEPENING UPR
TROF OVER CENTRAL NAMERICA DOWNSTREAM OF RDG OFF THE W COAST AS
FAIRLY VIGOROUS SHRTWV NEAR LK WINNIPEG IS DIGGING SEWD TOWARD NW
MN. SHRTWV RESPONSIBLE FOR PCPN ON SAT IS NOW OVER LOWER MI...AND
ARRIVAL OF MUCH DRIER AIR SHOWN ON THE 00Z INL RAOB IS TENDING TO
BREAK UP LINGERING FOG/LO CLD AT LEAST OVER THE WRN TIER DESPITE
UPSLOPE LLVL WNW FLOW IN WAKE OF SFC LO PRES TROF ASSOCIATED WITH
THAT DISTURBANCE. SINCE THE INCOMING AIRMASS WITH 00Z H85 TEMP OF
-2C AT INL IS NOT SUFFICIENTLY COLD FOR LES EITHER...THERE IS NO
PCPN. LOOKING UPSTREAM...AN AREA OF MID CLD IS PRESENT OVER NW MN/
NW ONTARIO AHEAD OF THE LK WINNIPEG SHRTWV AND ASSOCIATED COLD FNT
PLUNGING SSEWD. PCPN AHEAD OF THIS BNDRY IS ABSENT GIVEN THE DRYNESS
OF THE INL/YPL RAOBS DESPITE SOME RATHER SHARP DVPA/H85-5 QVECTOR
CNVGC...BUT SOME PLACES SHOW SN IMMEDIATELY BEHIND THE FROPA.
ALTHOUGH H85 TEMPS FALL SHARPLY BEHIND THE COLD FNT TO -14C AT THE
PAS IN MANITOBA NEAR LK WINNIPEG...THE 00Z RAOB FM THAT SITE SHOWS A
FAIRLY DRY AIRMASS/INVERTED V T-TD PROFILE BLO H85. BUT JUST TO THE
E WITHIN THE COLDER AIRMASS...MORE CLDS/-SN ARE EVIDENT IN FAR NW
ONTARIO.
MAIN FCST CONCERNS THRU TNGT ARE SHSN POTENTIAL AND WINDS ASSOCIATED
WITH AND FOLLOWING SHRTWV DIGGING TOWARD THE UPR GRT LKS/ATTENDANT
COLD FROPA.
EASTER SUN...AS LLVL DRY AIR MOVES IN EARLY THIS MRNG...EXPECT TREND
TOWARD FOG/ST TO BREAK UP W-E. BUT ARRIVAL OF COLD FNT OVER THE NW
BY LATE MRNG WL RESULT IN MORE CLDS AND SHSN IN THIS AREA AS AREA OF
MSTR IN NW MN/ADJOINING ONTARIO SWINGS OVHD. SINCE THE MOST
IMPRESSIVE DPVA/H85-5 QVECTOR CNVGC IS PROGGED TO SWING BY TO THE N
OF UPR MI...EXPECT ACCOMPANYING SHSN TO BE RELATIVELY MODEST EVEN IF
THERE IS SOME ENHANCEMENT OVER MAINLY THE HIER TERRAIN OF THE NW. AS
THE FNT SWINGS THRU THE REST OF THE CWA EARLY THIS AFTN...DEEP LYR
QVECTOR DVGC/MID LVL DRYING SHOULD LIMIT PCPN TO SCT -SHSN THAT WL
BE AT LEAST MIXED WITH RA OVER THE SCNTRL AS TEMPS RISE AOA 40 IN
THOSE DOWNSLOPE AREAS. BEST CHC FOR MORE NMRS SHSN WL BE OVER THE
NRN TIER CLOSER TO SHRTWV DYNAMICS. EVEN WITH STRENGTHENING NW
FLOW/CAD BEHIND THE FROPA THAT DROPS H85 TEMPS TO NEAR -14C BY 00Z
MON...ARRIVAL OF DRIER AIR MORE REPRESENTED BY THE 00Z YQD RAOB
ALONG WITH DAYTIME HEATING/INVERTED V LOOK TO GFS FCST SDNGS FOR CMX
SHOULD TEND TO LIMIT THE SHSN INTENSITY IN THE WAKE OF THE FROPA. AS
FOR THE WINDS...THE PREFERRED GFS SHOWS A FAIRLY SHARP PRES RISE
CENTER FOLLOWING THE FROPA AND REACHING NCENTRL LK SUP BY 00Z WITH
ISALLOBARIC WIND FAVORABLY ALIGNED WITH THE NW GRADIENT FLOW. SINCE
SEVERAL MODELS SHOW H925 WINDS UP TO 40 KTS STREAMING INTO THE ERN
ZNS AT 00Z WITH CONSIDERABLE CAD/DESTABILIZATION AS WELL AS THE
FAVORABLE ALIGNMENT OF THE ISALLOBARIC WIND TO THE GRADIENT FLOW...
EXPECT ADVY LVL GUSTS TO 45 MPH IN THE EXPOSED LK SUP SHORELINE E OF
MQT AFT 21Z.
AS THE CLOSED LO OVER SE CANADA MOVES TO THE E TNGT...SHARP CYC NW
FLOW IS PROGGED TO VEER A BIT MORE TOWARD THE NNW...WHICH MIGHT
ALLOW DEEPER MSTR NOW OVER NW ONTARIO TO INFILTRATE THE UPR LKS AS
SHOWN BY NMRS MODEL H7 RH PROGS. IN COMBINATION WITH H85 TEMPS
FALLING AS LO AS -17C TO -18C AND NOCTURNAL COOLING THAT WOULD FAVOR
MORE TYPICAL LES BANDING...MAINTAINED THE FLAVOR OF PREVIOUS FCST
WITH LES POPS INCRSG TO CATEGORICAL IN THE SN BELTS FAVORED BY THE
EXPECTED FLOW. NEARLY UNIDIRECTIONAL NATURE OF THE SFC-H85 FLOW IN
THE WELL MIXED CONVECTIVE LYR MIGHT ALSO FAVOR HEAVIER SN BANDS.
SINCE THE ERN ZNS WL BE CLOSER TO THE DEPARTING LO...HAVE A BETTER
OPPORTUNITY TO BE IMPACTED BY THE DEEPER MSTR...AND WL SEE ADVY LVL
WIND GUSTS AT LEAST THRU 06Z BEFORE THE PRES RISE CENTER SHIFTS
FARTHER E AND WEAKENS THE ISALLOBARIC WIND...OPTED TO ISSUE A WINTER
WX ADVY FOR ALGER/NRN SCHOOLCRAFT/LUCE COUNTIES FOR THE COMBINATION
OF STRONG WINDS...LES...AND BLSN.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 544 AM EDT SUN MAR 31 2013
AFTER A SEVERAL DAY STRETCH OF NEAR NORMAL EARLY SPRING WEATHER...IT
LOOKS LIKE A RETURN TO FEBRUARY LIKE WEATHER IS ON TAP FOR THE EARLY
PART OF THE WORK WEEK. COLD ADVECTION WILL CONTINUE ON MONDAY ON THE
BACKSIDE OF UPPER TROUGH PUSHING THROUGH THE UPPER LAKES. 85H TEMPS
FALL DOWN TO AROUND -18C ACROSS LAKE SUPERIOR DURING THE DAY ON
MONDAY. UNUSUAL TO BE DEALING WITH LAKE EFFECT IN EARLY APRIL BUT
WITH LAKE TEMPS BETWEEN 1-2C...SUFFICIENT DELTA TS WILL BE IN PLACE
FOR LAKE EFFECT SNOW IN NORTHWESTERLY WIND SNOW BELTS. THE CHALLENGE
OF THE FCST IS THE EXTENT OF ACCUMULATIONS AND OVERALL IMPACTS OF
THE SNOW. THE FACT THAT IT IS APRIL...FCST SOUNDINGS ARE SHOWING A
LOW LEVEL INVERTED V SIGNATURE...THE TYPICAL DISRUPTION IN THE LAKE
EFFECT PROCESS FROM DIURNAL HEATING THIS TIME OF YEAR...ALL LEND TO
THE UNCERTAINTY IN THE FCST. AREAS MOSTLY LIKELY TO SEE MORE OF THE
IMPACTS WILL BE ALGER AND LUCE COUNTIES AND WILL LET WINTER WEATHER
ADVISORY EXTEND THROUGH MONDAY MORNING TO ACCOUNT FOR FALLING SNOW
AND BLOWING SNOW...ESPECIALLY NEAR LAKE SUPERIOR. THE NEGATIVES
LISTED ABOVE MAY THEN BECOME TOO MUCH FOR SIGNIFICANT IMPACTS DURING
THE AFTERNOON MONDAY. AWAY FROM THIS AREA...EXPECT LAKE EFFECT SNOW
SNOW SHOWERS TO PRODUCE SOME LIGHT ACCUMULATIONS ACROSS THE KEWEENAW
AND WESTERN U.P. THE MOST NOTICEABLE THING ABOUT MONDAY WILL BE THE
FACT THAT TEMPERATURES WILL ONLY CLIMB INTO THE LOWER TO MID 20S AND
WITH GUSTY NORTHWEST WINDS IT WILL FEEL CONSIDERABLY COLDER.
THERE COULD BE A SLIGHT UPTICK IN LAKE EFFECT SNOW MONDAY NIGHT
ACROSS THE EAST WITH INVERSION HEIGHTS REMAINING AROUND
8KFT...TRAJECTORIES FAVORING A LITTLE MORE LOW LEVEL MOISTURE...AND
TYPICAL NIGHTTIME INCREASE IN LAKE EFFECT THIS TIME OF YEAR. MAY NEED
TO CONSIDER ANOTHER ADVISORY FOR ALGER AND LUCE COUNTIES AGAIN
MONDAY NIGHT. ELSEWHERE...EXPECT LAKE EFFECT SNOW SHOWERS TO
CONTINUE ACROSS THE WEST BUT ACCUMULATIONS SHOULD REMAIN RELATIVELY
LIGHT.
LAKE EFFECT PROCESS WINDS DOWN QUICKLY ON TUESDAY WITH INVERSION
LOWERING SIGNIFICANTLY AND SURFACE RIDGING APPROACHING FROM THE
WEST. TEMPERATURES WILL REMAIN WELL BELOW NORMAL...MORE LIKE MID
FEBRUARY.
RIDGE AXIS WILL MOVE ACROSS THE AREAM ON WEDNESDAY. WITH ABUNDANT
SUNSHINE AND WARM ADVECTION COMMENCING ON THE BACK SIDE OF THE RIDGE
TEMPS SHOULD REBOUND BACK ABOVE FREEZING TO WITHIN A FEW DEGREES OF
NORMAL. NEXT TROUGH AND FRONT WILL CROSS THE AREA ON THURSDAY. NOT
VERY MUCH MOISTURE TO WORK WITH SO ONLY EXPECT SOME LIGHT RAIN AND
SNOW SHOWERS WITH ITS PASSAGE. ANOTHER DECENT COLD SHOT WILL KNOCK
TEMPERATURES BACK BELOW NORMAL FOR FRIDAY. HAVENT LOOKED TOO MUCH AT
NEXT WEEKENDS FORECAST BUT THERE APPEARS TO BE A TREND POINTING
TOWARD A MORE SOUTHERN TRACK OF A STORM SYSTEM PUSHING THROUGH THE
LOWER LAKES. WILL BE SOMETHING TO KEEP AN EYE ON AS THE WEEK
PROGRESSES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 746 AM EDT SUN MAR 31 2013
WITH DRY AIR SHOWN ON THE 00Z INL RAOB DOMINATING EARLY IN THE FCST
PERIOD...VFR CONDITIONS WL PREDOMINATE. THE ARRIVAL OF A SHARP COLD
FNT OVER THE W BY LATE MRNG WL CAUSE SOME SHSN AND CONDITIONS TO
DETERIORATE TO MVFR AT CMX/IWD. THE BEST CHC FOR SOME HEAVIER SHSN
AND IFR CONDITIONS WL BE AT CMX...CLOSER TO THE INCOMING DISTURBANCE
AND WHERE NW FLOW WL UPSLOPE. GUSTY NW WINDS WL REACH AOA 30 KTS AT
THE MORE EXPOSED CMX LOCATION IN THE WAKE OF THE COLD FROPA THIS
AFTN. DOWNSLOPE NATURE OF THE FLOW AND GREATER DAYTIME HEATING/
MIXING INDICATES VFR CONDITIONS WL PREDOMINATE AT SAW MOST OF THE
DAY. WITH NOCTURNAL COOLING AND THE ARRIVAL OF SOME DEEPER MSTR...
EXPECT MVFR CONDITIONS WITH SOME SHSN TNGT AT ALL 3 SITES AS THE
GUSTY NW WINDS DRAW COLDER AIR INTO THE UPR LKS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 544 AM EDT SUN MAR 31 2013
AS A STRONG DISTURBANCE MOVES OVER LK SUP TODAY...A DEEP LO PRES
WILL TAKE SHAPE OVER SE CANADA AND CAUSE NW WIND TO INCREASE TO GALE
FORCE OVER THE NCENTRAL AND E PORTIONS OF THE LAKE BY THIS
AFTERNOON. THESE STRONG NW WINDS WILL CONTINUE TONIGHT AND DRAW MUCH
COLDER AIR INTO THE UPPER LAKES. THE RESULT WILL BE FREEZING SPRAY.
MAINTAINED GOING GALE WARNING FOR MOST OF THE NCENTRAL AND E HALF.
NORTHWEST GALES WILL CONTINUE ACROSS THE EASTERN HALF OF LAKE
SUPERIOR INTO TUESDAY BEFORE RIDGING BUILDS ACROSS THE LAKE WITH
WINDS DIMINISHING TO LESS THAN 20 KNOTS. WINDS SHOULD REMAIN BELOW
20 KNOTS INTO THURSDAY BEFORE THE NEXT QUICK MOVING FRONT MOVES
ACROSS THE UPPER GREAT LAKES. NORTHWEST WINDS TO 30 KNOTS WILL BE
POSSIBLE BEHIND THE FRONT TO END THE WORK WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 2 PM EDT
MONDAY FOR MIZ006-007-085.
LAKE SUPERIOR...
GALE WARNING FROM 2 PM THIS AFTERNOON TO 8 PM EDT TUESDAY FOR
LSZ264>267.
GALE WARNING FROM 2 PM THIS AFTERNOON TO 6 PM EDT MONDAY FOR
LSZ244-245-249>251.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...MZ
AVIATION...KC
MARINE...KC/MZ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
544 AM EDT SUN MAR 31 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 544 AM EDT SUN MAR 31 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A DEEPENING UPR
TROF OVER CENTRAL NAMERICA DOWNSTREAM OF RDG OFF THE W COAST AS
FAIRLY VIGOROUS SHRTWV NEAR LK WINNIPEG IS DIGGING SEWD TOWARD NW
MN. SHRTWV RESPONSIBLE FOR PCPN ON SAT IS NOW OVER LOWER MI...AND
ARRIVAL OF MUCH DRIER AIR SHOWN ON THE 00Z INL RAOB IS TENDING TO
BREAK UP LINGERING FOG/LO CLD AT LEAST OVER THE WRN TIER DESPITE
UPSLOPE LLVL WNW FLOW IN WAKE OF SFC LO PRES TROF ASSOCIATED WITH
THAT DISTURBANCE. SINCE THE INCOMING AIRMASS WITH 00Z H85 TEMP OF
-2C AT INL IS NOT SUFFICIENTLY COLD FOR LES EITHER...THERE IS NO
PCPN. LOOKING UPSTREAM...AN AREA OF MID CLD IS PRESENT OVER NW MN/
NW ONTARIO AHEAD OF THE LK WINNIPEG SHRTWV AND ASSOCIATED COLD FNT
PLUNGING SSEWD. PCPN AHEAD OF THIS BNDRY IS ABSENT GIVEN THE DRYNESS
OF THE INL/YPL RAOBS DESPITE SOME RATHER SHARP DVPA/H85-5 QVECTOR
CNVGC...BUT SOME PLACES SHOW SN IMMEDIATELY BEHIND THE FROPA.
ALTHOUGH H85 TEMPS FALL SHARPLY BEHIND THE COLD FNT TO -14C AT THE
PAS IN MANITOBA NEAR LK WINNIPEG...THE 00Z RAOB FM THAT SITE SHOWS A
FAIRLY DRY AIRMASS/INVERTED V T-TD PROFILE BLO H85. BUT JUST TO THE
E WITHIN THE COLDER AIRMASS...MORE CLDS/-SN ARE EVIDENT IN FAR NW
ONTARIO.
MAIN FCST CONCERNS THRU TNGT ARE SHSN POTENTIAL AND WINDS ASSOCIATED
WITH AND FOLLOWING SHRTWV DIGGING TOWARD THE UPR GRT LKS/ATTENDANT
COLD FROPA.
EASTER SUN...AS LLVL DRY AIR MOVES IN EARLY THIS MRNG...EXPECT TREND
TOWARD FOG/ST TO BREAK UP W-E. BUT ARRIVAL OF COLD FNT OVER THE NW
BY LATE MRNG WL RESULT IN MORE CLDS AND SHSN IN THIS AREA AS AREA OF
MSTR IN NW MN/ADJOINING ONTARIO SWINGS OVHD. SINCE THE MOST
IMPRESSIVE DPVA/H85-5 QVECTOR CNVGC IS PROGGED TO SWING BY TO THE N
OF UPR MI...EXPECT ACCOMPANYING SHSN TO BE RELATIVELY MODEST EVEN IF
THERE IS SOME ENHANCEMENT OVER MAINLY THE HIER TERRAIN OF THE NW. AS
THE FNT SWINGS THRU THE REST OF THE CWA EARLY THIS AFTN...DEEP LYR
QVECTOR DVGC/MID LVL DRYING SHOULD LIMIT PCPN TO SCT -SHSN THAT WL
BE AT LEAST MIXED WITH RA OVER THE SCNTRL AS TEMPS RISE AOA 40 IN
THOSE DOWNSLOPE AREAS. BEST CHC FOR MORE NMRS SHSN WL BE OVER THE
NRN TIER CLOSER TO SHRTWV DYNAMICS. EVEN WITH STRENGTHENING NW
FLOW/CAD BEHIND THE FROPA THAT DROPS H85 TEMPS TO NEAR -14C BY 00Z
MON...ARRIVAL OF DRIER AIR MORE REPRESENTED BY THE 00Z YQD RAOB
ALONG WITH DAYTIME HEATING/INVERTED V LOOK TO GFS FCST SDNGS FOR CMX
SHOULD TEND TO LIMIT THE SHSN INTENSITY IN THE WAKE OF THE FROPA. AS
FOR THE WINDS...THE PREFERRED GFS SHOWS A FAIRLY SHARP PRES RISE
CENTER FOLLOWING THE FROPA AND REACHING NCENTRL LK SUP BY 00Z WITH
ISALLOBARIC WIND FAVORABLY ALIGNED WITH THE NW GRADIENT FLOW. SINCE
SEVERAL MODELS SHOW H925 WINDS UP TO 40 KTS STREAMING INTO THE ERN
ZNS AT 00Z WITH CONSIDERABLE CAD/DESTABILIZATION AS WELL AS THE
FAVORABLE ALIGNMENT OF THE ISALLOBARIC WIND TO THE GRADIENT FLOW...
EXPECT ADVY LVL GUSTS TO 45 MPH IN THE EXPOSED LK SUP SHORELINE E OF
MQT AFT 21Z.
AS THE CLOSED LO OVER SE CANADA MOVES TO THE E TNGT...SHARP CYC NW
FLOW IS PROGGED TO VEER A BIT MORE TOWARD THE NNW...WHICH MIGHT
ALLOW DEEPER MSTR NOW OVER NW ONTARIO TO INFILTRATE THE UPR LKS AS
SHOWN BY NMRS MODEL H7 RH PROGS. IN COMBINATION WITH H85 TEMPS
FALLING AS LO AS -17C TO -18C AND NOCTURNAL COOLING THAT WOULD FAVOR
MORE TYPICAL LES BANDING...MAINTAINED THE FLAVOR OF PREVIOUS FCST
WITH LES POPS INCRSG TO CATEGORICAL IN THE SN BELTS FAVORED BY THE
EXPECTED FLOW. NEARLY UNIDIRECTIONAL NATURE OF THE SFC-H85 FLOW IN
THE WELL MIXED CONVECTIVE LYR MIGHT ALSO FAVOR HEAVIER SN BANDS.
SINCE THE ERN ZNS WL BE CLOSER TO THE DEPARTING LO...HAVE A BETTER
OPPORTUNITY TO BE IMPACTED BY THE DEEPER MSTR...AND WL SEE ADVY LVL
WIND GUSTS AT LEAST THRU 06Z BEFORE THE PRES RISE CENTER SHIFTS
FARTHER E AND WEAKENS THE ISALLOBARIC WIND...OPTED TO ISSUE A WINTER
WX ADVY FOR ALGER/NRN SCHOOLCRAFT/LUCE COUNTIES FOR THE COMBINATION
OF STRONG WINDS...LES...AND BLSN.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 544 AM EDT SUN MAR 31 2013
AFTER A SEVERAL DAY STRETCH OF NEAR NORMAL EARLY SPRING WEATHER...IT
LOOKS LIKE A RETURN TO FEBRUARY LIKE WEATHER IS ON TAP FOR THE EARLY
PART OF THE WORK WEEK. COLD ADVECTION WILL CONTINUE ON MONDAY ON THE
BACKSIDE OF UPPER TROUGH PUSHING THROUGH THE UPPER LAKES. 85H TEMPS
FALL DOWN TO AROUND -18C ACROSS LAKE SUPERIOR DURING THE DAY ON
MONDAY. UNUSUAL TO BE DEALING WITH LAKE EFFECT IN EARLY APRIL BUT
WITH LAKE TEMPS BETWEEN 1-2C...SUFFICIENT DELTA TS WILL BE IN PLACE
FOR LAKE EFFECT SNOW IN NORTHWESTERLY WIND SNOW BELTS. THE CHALLENGE
OF THE FCST IS THE EXTENT OF ACCUMULATIONS AND OVERALL IMPACTS OF
THE SNOW. THE FACT THAT IT IS APRIL...FCST SOUNDINGS ARE SHOWING A
LOW LEVEL INVERTED V SIGNATURE...THE TYPICAL DISRUPTION IN THE LAKE
EFFECT PROCESS FROM DIURNAL HEATING THIS TIME OF YEAR...ALL LEND TO
THE UNCERTAINTY IN THE FCST. AREAS MOSTLY LIKELY TO SEE MORE OF THE
IMPACTS WILL BE ALGER AND LUCE COUNTIES AND WILL LET WINTER WEATHER
ADVISORY EXTEND THROUGH MONDAY MORNING TO ACCOUNT FOR FALLING SNOW
AND BLOWING SNOW...ESPECIALLY NEAR LAKE SUPERIOR. THE NEGATIVES
LISTED ABOVE MAY THEN BECOME TOO MUCH FOR SIGNIFICANT IMPACTS DURING
THE AFTERNOON MONDAY. AWAY FROM THIS AREA...EXPECT LAKE EFFECT SNOW
SNOW SHOWERS TO PRODUCE SOME LIGHT ACCUMULATIONS ACROSS THE KEWEENAW
AND WESTERN U.P. THE MOST NOTICEABLE THING ABOUT MONDAY WILL BE THE
FACT THAT TEMPERATURES WILL ONLY CLIMB INTO THE LOWER TO MID 20S AND
WITH GUSTY NORTHWEST WINDS IT WILL FEEL CONSIDERABLY COLDER.
THERE COULD BE A SLIGHT UPTICK IN LAKE EFFECT SNOW MONDAY NIGHT
ACROSS THE EAST WITH INVERSION HEIGHTS REMAINING AROUND
8KFT...TRAJECTORIES FAVORING A LITTLE MORE LOW LEVEL MOISTURE...AND
TYPICAL NIGHTTIME INCREASE IN LAKE EFFECT THIS TIME OF YEAR. MAY NEED
TO CONSIDER ANOTHER ADVISORY FOR ALGER AND LUCE COUNTIES AGAIN
MONDAY NIGHT. ELSEWHERE...EXPECT LAKE EFFECT SNOW SHOWERS TO
CONTINUE ACROSS THE WEST BUT ACCUMULATIONS SHOULD REMAIN RELATIVELY
LIGHT.
LAKE EFFECT PROCESS WINDS DOWN QUICKLY ON TUESDAY WITH INVERSION
LOWERING SIGNIFICANTLY AND SURFACE RIDGING APPROACHING FROM THE
WEST. TEMPERATURES WILL REMAIN WELL BELOW NORMAL...MORE LIKE MID
FEBRUARY.
RIDGE AXIS WILL MOVE ACROSS THE AREAM ON WEDNESDAY. WITH ABUNDANT
SUNSHINE AND WARM ADVECTION COMMENCING ON THE BACK SIDE OF THE RIDGE
TEMPS SHOULD REBOUND BACK ABOVE FREEZING TO WITHIN A FEW DEGREES OF
NORMAL. NEXT TROUGH AND FRONT WILL CROSS THE AREA ON THURSDAY. NOT
VERY MUCH MOISTURE TO WORK WITH SO ONLY EXPECT SOME LIGHT RAIN AND
SNOW SHOWERS WITH ITS PASSAGE. ANOTHER DECENT COLD SHOT WILL KNOCK
TEMPERATURES BACK BELOW NORMAL FOR FRIDAY. HAVENT LOOKED TOO MUCH AT
NEXT WEEKENDS FORECAST BUT THERE APPEARS TO BE A TREND POINTING
TOWARD A MORE SOUTHERN TRACK OF A STORM SYSTEM PUSHING THROUGH THE
LOWER LAKES. WILL BE SOMETHING TO KEEP AN EYE ON AS THE WEEK
PROGRESSES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 134 AM EDT SUN MAR 31 2013
ARRIVAL OF DRIER AIR SHOWN ON THE 00Z INL RAOB WILL RESULT IN VFR
CONDITIONS EARLY THIS MRNG AT CMX/IWD AND A BREAKUP OF THE
FOG/ST/IFR CONDITIONS NOW IMPACTING SAW BY 09Z. EXPECT INCREASING
POTENTIAL OF -SHSN AT WRN TAF SITES BY LATE MRNG AS CONDITIONS FALL
TO MVFR AT CMX/IWD WITH ARRIVAL OF NEXT DISTURBANCE. GUSTY WNW WINDS
WILL DEVELOP FOLLOWING NEXT SFC TROF PASSAGE LATE THIS MORNING. WNW
AND COLD ADVECTION BEHIND FRONT WILL BRING A CHANCE OF -SHSN SUNDAY
AFTERNOON AT KSAW ALONG WITH MVFR CIGS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 544 AM EDT SUN MAR 31 2013
AS A STRONG DISTURBANCE MOVES OVER LK SUP TODAY...A DEEP LO PRES
WILL TAKE SHAPE OVER SE CANADA AND CAUSE NW WIND TO INCREASE TO GALE
FORCE OVER THE NCENTRAL AND E PORTIONS OF THE LAKE BY THIS
AFTERNOON. THESE STRONG NW WINDS WILL CONTINUE TONIGHT AND DRAW MUCH
COLDER AIR INTO THE UPPER LAKES. THE RESULT WILL BE FREEZING SPRAY.
MAINTAINED GOING GALE WARNING FOR MOST OF THE NCENTRAL AND E HALF.
NORTHWEST GALES WILL CONTINUE ACROSS THE EASTERN HALF OF LAKE
SUPERIOR INTO TUESDAY BEFORE RIDGING BUILDS ACROSS THE LAKE WITH
WINDS DIMINISHING TO LESS THAN 20 KNOTS. WINDS SHOULD REMAIN BELOW
20 KNOTS INTO THURSDAY BEFORE THE NEXT QUICK MOVING FRONT MOVES
ACROSS THE UPPER GREAT LAKES. NORTHWEST WINDS TO 30 KNOTS WILL BE
POSSIBLE BEHIND THE FRONT TO END THE WORK WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 2 PM EDT
MONDAY FOR MIZ006-007-085.
LAKE SUPERIOR...
GALE WARNING FROM 2 PM THIS AFTERNOON TO 8 PM EDT TUESDAY FOR
LSZ264>267.
GALE WARNING FROM 2 PM THIS AFTERNOON TO 6 PM EDT MONDAY FOR
LSZ244-245-249>251.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...MZ
AVIATION...KC
MARINE...KC/MZ
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
659 AM CDT SUN MAR 31 2013
.SHORT TERM...(EASTER SUNDAY)
ISSUED AT 224 AM CDT SUN MAR 31 2013
FORECAST HAS CHANGED TODAY GIVEN CURRENT CONDITIONS AND LATEST SHORT
RANGE MODEL GUIDANCE. SHORTWAVE ENERGY...EVIDENT ON LATEST WATER
VAPOR IMAGERY...DROPPING SOUTHEAST FROM SOUTHERN NEBRASKA HAS LED TO
A LARGE AREA OF SHOWERS AND SOME THUNDERSTORMS DEVELOPING ACROSS
EASTERN KANSAS AND WEST CENTRAL MISSOURI.
LATEST RUC AND HRRR SHOW THIS AREA OF RAIN SHOWERS/STORMS EXPANDING
AS EAST/SOUTHEAST THIS MORNING ACROSS CENTRAL MISSOURI AND THE
OZARKS...PERHAPS GRAZING EAST CENTRAL MISSOURI AND SOUTHWEST
ILLINOIS. WILL FINE TUNE POPS BEFORE FORECAST ISSUANCE BASED ON THE
VERY LATEST RADAR TRENDS.
THERE WILL OBVIOUSLY BE A SLOWER CLEARING TREND TO THE CLOUDS THANKS
TO THIS SHORTWAVE...AND FEEL IT PRUDENT TO SIDE WITH SLIGHTLY COOLER
MAV GUIDANCE FOR HIGH TEMPERATURES.
TO COMPLICATE THE FORECAST EVEN FURTHER...MUCH OF THE EXPLICIT AND
HIGH RESOLUTION MODEL GUIDANCE DEPICT SOME ISOLATED SHOWERS
DEVELOPING ALONG A PREFRONTAL TROF THIS AFTERNOON AND EVENING FROM
CENTRAL ILLINOIS TOWARD THE ST. LOUIS METRO AREA. SO HAVE INCLUDED
SOME LOW CHANCE/ISOLATED POPS FOR THIS AS WELL.
CVKING
&&
.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 224 AM CDT SUN MAR 31 2013
(TONIGHT AND MONDAY)
ARCTIC COLD FRONT EXPECTED TO MOVE SOUTH ACROSS THE CWA TONIGHT
WITH NORTH WIND AND COLD ADVECTION TAKING CONTROL OF THE WEATHER
FOR THE EARLY PART OF THE WORK WEEK. LATEST GUIDANCE CONTINUES TO
DEPICT A BAND OF LIGHT POST FRONTAL PRECIPITATION AFFECTING MAINLY
NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS SUNDAY NIGHT. THIS
PRECIPITATION SHOULD WEAKEN AS IT PROGRESSES SOUTH MONDAY MORNING
TO THE I-70 CORRIDOR. MAINTAINED RAIN/SNOW MIX...BUT DONT EXPECT
ANY ACCUMULATION DUE TO WARM AIR AND GROUND TEMPERATURES. HAVE
SIDED WITH COOLER MET GUIDANCE FOR TEMPERATURES.
(TUESDAY THROUGH SATURDAY)
SLOW WARMING TREND EXPECTED WITH HIGH PRESSURE MOVING EAST OF THE
AREA BY LATE IN THE WEEK. HAVE KEPT FORECAST DRY AS GUIDANCE KEEPS
CUTOFF LOW TO THE SOUTH OF THE AREA THURSDAY.
CVKING
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 640 AM CDT SUN MAR 31 2013
IFR CIGS/VSBYS WILL CONTINUE TO BE POSSIBLE ACROSS MUCH OF CENTRAL
AND NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS UNTIL 14-15Z.
ANOTHER AREA OF IFR OVER SOUTHWEST AND SOUTH CENTRAL ILLINOIS WILL
LIKELY PERSIST UNTIL 15Z AS WELL. AFTER THAT...EXPECT VFR FLIGHT
CONDITIONS TO PREVAIL TODAY AHEAD OF A STRONG COLD FRONT. WILL
LIKELY ALSO SEE SOME GUSTY WEST-NORTHWEST WINDS OF UP TO AROUND
25KTS TODAY AHEAD OF THE FRONT. WILL EXPECT TO SEE WINDS DROP OFF
AROUND 00Z. COLD FRONT WILL MOVE THROUGH THE AREA THIS
EVENING...SHIFTING THE WIND TO THE NORTH. THERE MAY BE SOME LIGHT
RAIN OR LIGHT SNOW NORTH OF I-70 TONIGHT
SPECIFICS FOR KSTL...
EXPECT MVFR FLIGHT CONDITIONS TO PREVAIL FOR A FEW MORE HOURS THIS
MORNING AT LAMBERT BEFORE RISING TO VFR BETWEEN 14-15Z. THERE IS A
CHANCE THAT CIGS OR VSBYS COULD DROP BACK BRIEFLY INTO IFR
RANGE...BUT THE CHANCE OF THAT HAPPENING IS RAPIDLY DIMINISHING
WITH SUNRISE AND DRIER AIR MOVING IN FROM THE NORTHWEST. WIND WILL
PICK UP BY EARLY THIS AFTERNOON AND WE COULD SEE GUSTS TO AROUND
25KTS. WIND SHOULD DIMINISH BY AROUND 00Z. COLD FRONT WILL MOVE
THROUGH THE TERMINAL AROUND 06Z TONIGHT WHICH WILL SHIFT THE WIND
TO THE NORTH. CURRENT INDICATIONS ARE THAT THE FRONT WILL GO
THROUGH DRY AND CEILINGS WILL STAY ABOVE 5000FT UNTIL AROUND 12Z
MONDAY MORNING.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BUFFALO NY
734 AM EDT SUN MAR 31 2013
.SYNOPSIS...
SOUTHERLY WINDS WILL BRING A MILD DAY TODAY BEFORE A COLD FRONT
APPROACHES WITH SHOWERS DEVELOPING DURING THE AFTERNOON. THE COLD
FRONT WILL USHER IN MUCH COLDER TEMPERATURES FOR THE FIRST HALF OF
NEXT WEEK ALONG WITH SCATTERED SNOW SHOWERS AND HEAVIER LAKE EFFECT
SNOW EAST OF THE LAKES.
&&
.NEAR TERM /THROUGH TONIGHT/...
LEAD SHORTWAVE CURRENTLY LIFTING INTO THE OHIO VALLEY. ASSOCIATED
SHOWER ACTIVITY SHOWING UP ON UPSTREAM REGIONAL RADARS ACROSS
WESTERN OHIO. THIS ACTIVITY IS IN DECENT AGREEMENT WITH LATEST
HIGHER RESOLUTION HRRR RUN WHICH BRINGS THE LEADING EDGE OF SHOWERS
ASSOCIATED WITH THIS SHORTWAVE INTO THE SOUTHERN TIER AND WESTERN
FINGER LAKES BETWEEN 10 AM AND 2 PM.
MODELS CONTINUING TO AGREE UPON THE SPLIT IN PRECIPITATION PATTERN
BETWEEN THE SOUTHERN AREA OF PRECIPITATION ASSOCIATED WITH THE
SHORTWAVE WORKING THROUGH THE OHIO VALLEY... AND THE NORTHERN STREAM
SYSTEM WHICH LAGS BEHIND BY SEVERAL HOURS. THE NORTHERN SYSTEM WILL
GENERATE ADDITIONAL WIDESPREAD SHOWER ACTIVITY BY EARLY TO MID
AFTERNOON AS THE ASSOCIATED COLD FRONT APPROACHES THE REGION. SPC
SREF PARAMETERS KEEP PRIMARY INSTABILITY AXIS WELL SOUTH OF THE
AREA...THEREFORE NO NEED TO INCLUDE MENTION OF THUNDER IN THE
FORECAST.
AHEAD OF THE FRONT AND BEFORE THE RAIN ARRIVES...THE SOUTHERLY
DOWNSLOPE FLOW COMBINED WITH WARMER TEMPERATURES ALOFT WILL ALLOW
THE LAKE PLAINS TO WARM WELL INTO THE 50S. THE HIGHER TERRAIN OF THE
INTERIOR SOUTHERN TIER AND EAST OF LAKE ONTARIO WILL TOP OUT IN THE
MID TO UPPER 40S WITHOUT THE BENEFIT OF DOWNSLOPE FLOW AND AN
EARLIER START TO THE RAIN.
THE COLD FRONT WILL BE PUSH THROUGH EARLY TONIGHT. THE COLD AIR
ADVECTION IS QUITE IMPRESSIVE BEHIND THE FRONT AND WE SHOULD SEE A
CHANGE OVER TO SNOW OR A MIX BRIEFLY BEFORE THE PRECIPITATION
DIMINISHES OVERNIGHT. WIND SHOULD PICK UP IN THE STRONG COLD AIR
ADVECTIVE PATTERN...BUT SHOULD BE LIMITED TO GUSTS TO NEAR 30 MPH.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AN ARCTIC FRONT WILL CROSS THE REGION MONDAY MORNING WITH A
CHANGEOVER FROM RAIN TO SNOW SHOWERS. 850MB TEMPS AT 12Z MONDAY WILL
RANGE -12C AT THE NIAGARA RIVER TO -4C ACROSS CENTRAL NY...FALLING
TO -12C TO -13C BY 00Z TUESDAY. THESE BOUNDARY LAYER TEMPS WILL BE
SUFFICIENTLY COLD TO SUPPORT SOME LAKE EFFECT RESPONSE...BUT THE
DESTABILIZING EFFECT OF EARLY APRIL SUNSHINE WILL DISRUPT ANY
CONCENTRATED PRECIP...WILL HAVE LIKELY POPS FOR SMALL ACCUMULATIONS
BUT DO NOT EXPECT ANY SIGNIFICANT ACCUMS UNTIL OVERNIGHT MONDAY
NIGHT TO TUESDAY MORNING. WELL ALIGNED WESTERLY WINDS WILL FOCUS THE
LAKE SNOW ON THE HIGHER TERRAIN OF THE WESTERN SOUTHERN TIER AND ON
THE TOP OF THE TUG HILL PLATEAU EAST OF LAKE ONTARIO. THE LONGER
FETCH ALONG THE LENGTH OF LAKE ONTARIO WILL ALLOW THE TUG HILL TO
APPRECIATE A BETTER CHANCE FOR SIGNIFICANT SNOW ACCUMULATION MONDAY
NIGHT THROUGH EARLY WEDNESDAY. BOTH 00Z GFS AND ECMWF SHOW A WEAK
SHORT WAVE CROSSING THE EASTERN GREAT LAKES ON WEDNESDAY WITH ONLY
CHANCE POPS ASSOCIATED...LIMITING FACTORS AS THE LACK OF DEEP
MOISTURE AND SURFACE HIGH PRESSURE STARTING TO BUILD IN FROM THE
WEST.
IT IS POSSIBLE THAT THIS LAKE EFFECT EVENT FROM MONDAY NIGHT TO
WEDNESDAY MORNING MAY BRING WARNING CRITERIA SNOWS AS SUGGESTED BY
RECENT CIPS ANALOGS OF THE TOP 15 MOST SIMILAR EVENTS. ACCUMULATIONS
OF 6 TO 12 INCHES OR MORE MAY BE POSSIBLE UNDER THE MOST PERSISTENT
BANDS. THE DURATION OF THE EVENT WILL LIKELY LEAD TO THE HIGHER
ACCUMULATIONS...EVEN WITH THE LIMITING FACTOR OF LESS THAN OPTIMAL
MOISTURE PROFILE AND THE DISRUPTIVE INSOLATION EFFECTS DURING THE
DAYTIME. WILL CONTINUE TO HIGHLIGHT THIS EVENT IN THE HWO...BUT WILL
HOLD OFF FOR ANOTHER MODEL RUN TO ASSESS THE POSSIBILITY OF A LAKE
SNOW WATCH.
TEMPERATURES WILL REMAIN WELL BELOW NORMAL THROUGH MONDAY AND
TUESDAY. THE COLD AIR ADVECTION WILL KEEP HIGHS LIMITED TO THE LOW
AND MID 30S...AND ONLY UPPER 20S OVER THE HIGHER TERRAIN OF THE
WESTERN SOUTHERN TIER AND TUG HILL ON TUESDAY. OVERNIGHT LOWS WILL
BE IN THE 20S MONDAY AND TUESDAY NIGHTS. WEDNESDAY WILL HAVE A
SLIGHT RISE IN TEMPS WITH HIGHS IN THE 30S ACROSS THE REGION AND
BACK TO 20S WEDNESDAY NIGHT.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
NOW HERE IS THE GOOD NEWS...WE BEGIN TO SEE TEMPERATURES MODERATING
BACK TO NORMAL THROUGH NEXT WEEKEND.
WE WILL SEE SOME BRIEF RIDGING ON THURSDAY BRINGING A SUNNY DAY WITH
WARMER TEMPS RISING INTO THE UPPER 40S. SIMILAR CONDITIONS TO WHAT
WE SAW THIS FINE SATURDAY AFTERNOON. THE FORECAST BECOMES A BIT
DIFFICULT ON FRIDAY WHERE BOTH GFS AND EC MODELS PHASE THE TWO
SHORTWAVES TOGETHER ALONG THE EAST COAST WITH DEEP SURFACE
CYCLOGENESIS OCCURRING. THERE ARE SOME DIFFERENCES IN TIMING AND
LOCATION OF THE FORMATION OF A STRONG SURFACE LOW BUT GENERALLY THE
MODELS LIFT IT FROM THE CAROLINA COAST NORTH TOWARD NEW ENGLAND BY
FRIDAY NIGHT. ANOTHER WEAKER SYSTEM WILL DRIFT ACROSS EASTERN
CANADA. THERE IS POTENTIAL FOR EITHER SYSTEM TO CLIP OUR FORECAST
AREA SO WILL GO WITH LOW CHANGE FOR SHOWERS AT THIS TIME.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS THIS MORNING WILL DETERIORATE TO MVFR IN AREAS OF
RAIN SHOWERS DURING THE MID TO LATE AFTERNOON...WITH IFR POSSIBLE
ACROSS THE HIGHER TERRAIN. S-SW SURFACE WINDS WILL INCREASE TO
15-25 KTS LATER THIS MORNING AND AFTERNOON. A FRONTAL BOUNDARY WILL
CROSS THIS EVENING WITH WINDS SHIFTING TO THE SOUTHWEST BETWEEN
21Z-03Z...THEN TO THE WEST BETWEEN 06Z AND 12Z.
OUTLOOK...
MONDAY...VFR/MVFR WITH A FEW SNOW SHOWERS LIKELY.
MONDAY NIGHT THROUGH TUESDAY NIGHT...VFR/MVFR WITH A CHANCE OF SNOW
SHOWERS...EXCEPT IFR IN LAKE EFFECT SNOW EAST OF THE LAKES.
WEDNESDAY...VFR/MVFR WITH A CHANCE OF SNOW SHOWERS.
THURSDAY...VFR.
&&
.MARINE...
SOUTHERLY WINDS WILL INCREASE TODAY AS THE PRESSURE GRADIENT
TIGHTENS AHEAD OF AN APPROACHING COLD FRONT. THE COLD FRONT WILL
SWEEP ACROSS THE LOWER LAKES TONIGHT. FOLLOWING THE FRONT MODERATE
TO STRONG WESTERLIES WILL BRING AN EXTENDED PERIOD OF SMALL CRAFT
CONDITIONS TO BOTH LAKES THROUGH MIDWEEK. WINDS MAY GET CLOSE TO
GALE FORCE AT TIMES MONDAY AND TUESDAY ON LAKE ONTARIO.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 10 PM EDT MONDAY FOR LEZ040-
041.
SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO 6 AM EDT
TUESDAY FOR LOZ042-043.
SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY
FOR LOZ044-045.
&&
$$
SYNOPSIS...TMA
NEAR TERM...TMA
SHORT TERM...WCH
LONG TERM...SMITH/WCH
AVIATION...TMA
MARINE...TMA
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
642 AM EDT SUN MAR 31 2013
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL MOVE THROUGH THE AREA THIS MORNING.
A COLD FRONT WILL FOLLOW TONIGHT. HIGH PRESSURE WILL BUILD IN FOR
THE FIRST HALF OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RADAR SHOWS ECHOES MOVING ACROSS THE SOUTHERN PART OF THE FORECAST
AREA EARLY THIS MORNING. THESE WILL CONTINUE TO MOVE EAST AND MAY
CLEAR THE AREA SHORTLY AFTER DAYBREAK. A TROUGH OF LOW PRESSURE IN
INDIANA WILL PUSH ACROSS THE AREA DURING THE MORNING AS WELL. SO
FAR ONLY A FEW SHOWERS ALONG AND AHEAD OF IT. BUT RECENT HRRR AND
RAP RUNS SUGGEST THAT COVERAGE COULD INCREASE AS IT MOVES INTO THE
REGION. THERE SHOULD BE SOME BREAK IN THE CLOUDS AFTER THE TROUGH
PASSES AND WINDS COULD GUST UP TO 30 MPH. TRAILING SHORT WAVE WILL
MOVE ACROSS THE REGION IN THE AFTERNOON AND CANNOT RULE OUT A FEW
ADDITIONAL SHOWERS WITH IT ESPECIALLY IF THERE IS SUFFICIENT
HEATING. RAINFALL AMOUNTS TODAY WILL BE LIGHT. HIGHS ARE FORECAST
TO BE NEAR PERSISTENCE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
A COLD FRONT WILL MOVE SOUTHEAST ACROSS THE AREA TONIGHT. APPEARS
THAT A FEW SHOWERS COULD ACCOMPANY THE BOUNDARY. 00Z MODELS
CONTINUE TO TREND DRIER ON MONDAY. BUT CANNOT COMPLETELY DISCOUNT
THE POSSIBILITY OF A SHOWER OR TWO AS A SHORT WAVE DROPS INTO THE
BASE OF AN UPPER TROUGH. AT THIS POINT FELT THAT NOTHING MORE THAN
SLIGHT CHANCE WAS WARRANTED FOR EITHER TONIGHT OR MONDAY. HIGH
PRESSURE WILL RIDGE IN FROM THE NORTHWEST THROUGH THE REMAINDER OF
THE PERIOD AS NORTHWEST UPPER FLOW CONTINUES. WITH THE TRANSITION
IN AIR MASS TONIGHT LOWS MAY END UP BEING NEAR NORMAL. BUT
THEREAFTER READINGS WILL BE BACK TO WELL BELOW SEASONAL AVERAGE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
UPPER TROUGH WILL DEPART EARLY IN THE PERIOD WITH THE SURFACE HIGH
FINALLY BUILDING ACROSS THE AREA. THIS WILL ALLOW TEMPERATURES TO
BEGIN TO MODERATE MID WEEK. A WELL DEVELOPED SYSTEM IS FORECAST
TO PASS SOUTH OF THE REGION THURSDAY NIGHT AND FRIDAY. THERE IS
SOME UNCERTAINTY WITH HOW FAR NORTH THE PRECIPITATION SHIELD WILL
SPREAD. BUT WITH THE 00Z ECMWF...CANADIAN AND GEFS MEAN SUGGESTING
THAT PRECIPITATION COULD SNEAK UP INTO THE FAR SOUTHEAST
COUNTIES...FELT THAT ADDING LOW CHANCE POPS WAS PRUDENT AT THIS
POINT. ANOTHER HIGH WILL BUILD IN SATURDAY AFTER THIS SYSTEM PASSES
OFF TO THE EAST. TEMPERATURES SHOULD BE NEAR NORMAL FOR THE LATTER
PART OF THE WEEK.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
A DISTURBANCE WILL CONTINUE TO WORK THROUGH THE TAF SITES THIS
MORNING. COVERAGE IN RAIN SHOWERS WILL DECREASE FROM WEST TO EAST
AS THE MORNING PROGRESSES. SOME MVFR VSBYS MAY BE POSSIBLE IN SOME
OF THE SHOWER ACTIVITY. AFTER THE MAIN SHOWER ACTIVITY THERE IS AN
AREA OF LOWER CIGS AND VSBYS CURRENTLY SW OF THE TAF SITES. HAVE
MVFR CIGS AND SOME MVFR VSBYS WORKING INTO THE AREA TODAY. WINDS
WILL PICK UP FOR THE DAYTIME HOURS TODAY WITH SOME WIND GUSTS
UPWARDS OF 20 TO 25 KNOTS. BY LATE IN THE DAY EXPECT VFR
CONDITIONS TO RETURN. ANOTHER DISTURBANCE WILL WORK INTO THE TAF
SITES TONIGHT ALLOWING FOR SOME ADDITIONAL LIGHT PRECIPITATION
ACROSS THE REGION. EXPECT MVFR CIGS TO AGAIN WORK INTO THE AREA
TONIGHT ACROSS THE TAF SITES.
OUTLOOK...MVFR CONDITIONS POSSIBLE ON MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...NOVAK
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1000 AM CDT SUN MAR 31 2013
.DISCUSSION...JUST MADE SOME MINOR MODIFICATIONS TO GRIDS (MAINLY
MOISTURE AND MINOR AT THAT) BUT OTHERWISE NO REAL CHANGES NEEDED.
NEW NAM12 RUN HAS CONVECTION APPROACHING AREA AROUND 00Z BUT THEN
WEAKENS IT AS IT MOVES SOUTHWARD. HRRR MODEL HAS CONVECTION TOO
BUT FARTHER EAST AND PUSHES IT A BIT FARTHER SOUTH (BUT NOT MUCH).
ALL IN ALL...THIS JUSTIFIES MAINTAINING THE 20 POPS OVER THE
NORTHERN TIER OF AREA AS PREVIOUSLY FORECAST FOR TODAY. WILL LET
TEMPERATURE FORECAST RIDE. WILL UPDATE PFM AND AFM TEXT PRODUCTS
BUT ZFPCRP SEEMS OK FOR NOW.
&&
.MARINE...HAVE HAD OBSERVATIONS OF FOG/SEA FOG OVER THE GULF
WATERS THIS MORNING...PATCHY DENSE AT TIMES. HAVE WRITTEN MARINE
WEATHER STATEMENT TO HIGHLIGHT CONCERN MAINLY FOR TONIGHT AND
MONDAY...AS SOME OBSERVATIONS HAVE DEW POINTS AROUND 70F THIS
MORNING AND SHELF TEMPS STILL IN THE MID/UPPER 60S. WILL LOOK AT
LATER PERIODS ONCE NEW MODEL RUNS AND OBSERVATIONS COME IN.
&&
.PREV DISCUSSION... /ISSUED 626 AM CDT SUN MAR 31 2013/
DISCUSSION...UPDATE FOR 12Z AVIATION.
AVIATION...BKN-OVC 500-1500 STRATUS DECK IN PLACE ACROSS EASTERN
PORTIONS OF SOUTH TEXAS THIS MORNING...ALONG A HBV-BEA-VCT LINE
EAST TO THE COAST. STRATUS DECK WILL GRADUALLY ERODE 15Z-18Z WITH
VFR CONDITIONS FOR THIS AFTERNOON. S TO SE WINDS 6-12 KTS INCREASING
TO 10-15 KTS AFTER 15Z...AND INCREASING FURTHER AT CRP 15-20 KTS
WITH GUSTS TO 25 KTS THIS AFTERNOON. IFR CIGS WILL QUICKLY
RE-DEVELOP EARLY THIS EVENING FROM E TO W.
PREV DISCUSSION... /ISSUED 351 AM CDT SUN MAR 31 2013/
SHORT TERM (TODAY THROUGH MONDAY)...MID AND UPPER LEVEL SHORTWAVE
DIVING SOUTHEAST THROUGH SOUTH-CENTRAL PLAINS EARLY THIS MORNING
WITH A SECOND SHORTWAVE TROUGH ACROSS NEW MEXICO TRACKING EAST INTO
TEXAS. COLD FRONT HAS ENTERED THE PANHANDLE AND WILL PUSH SOUTH
THROUGH WEST-CENTRAL TEXAS THIS MORNING. SOUTH OF THE FRONT ACROSS
SOUTH TEXAS...WARM CONDITIONS WILL PREVAIL FOR THIS EASTER SUNDAY.
INITIALLY MODELS INDICATING SOME SLIGHT DRYING TAKING PLACE NOW
THROUGH 18Z IN THE 925MB-850MB LAYER...BUT THEN MOISTENING BACK UP
ACROSS THE CENTRAL AND NORTHERN COUNTIES LATE THIS AFTERNOON...IN
ADVANCE OF THE WEAKENING COLD FRONT ENTERING THE HILL COUNTRY AND
SOUTH-CENTRAL TEXAS. BACKING LOW LEVEL FLOW AHEAD OF THE SYSTEM
MAY YIELD AN ISOLATED SHOWER OR THUNDERSTORMS ACROSS THE CENTRAL
COUNTIES LATER THIS AFTERNOON WHERE PWATS POOLED AROUND 1.5"...BUT
THE MAIN AREA TO WATCH WILL BE UPSTREAM CONVECTION ACROSS THE EWX
CWA CLOSER TO THE FRONT AND SECOND SHORTWAVE. HI RESOLUTIONS
MODELS HAVE BEEN INDICATING THIS CONVECTION POSSIBLY MAKING IT
INTO THE FAR NORTHERN CWA LATE AFTERNOON/EARLY EVENING...WITH 00Z
ECMWF AND 00Z NAM12 ALSO HINTING AT THIS. SHOULD NOTE THAT THE 00Z
4KM ARW/NMM WAS SHOWING CONVECTIVE COMPLEX REACHING THE COAST THIS
EVENING BUT AM DISCOUNTING THIS FOR THE TIME BEING...AND THINKING
THAT IF CONVECTION MAKES IT INTO THE AREA...IT WOULD LIKELY BE
CONFINED TO NORTHERN AND WESTERN AREAS OF THE CWA...AS CIN WOULD
BE RAPIDLY INCREASING IN THE EARLY EVENING ACROSS THE COASTAL
PLAINS BEHIND THE SEA-BREEZE. GIVEN THE INSTABILITY FORECAST TO
DEVELOP LATE AFTERNOON ACROSS THE BRUSH COUNTRY (1700-2000 J/KG
CAPE)...STEEP MID LEVEL LAPSE RATES...AND DEEP LAYER SHEAR OF
AROUND 50 KTS OVER THE CWA...ISOLATED STRONG TO SEVERE STORMS ARE
POSSIBLE. SPC HAS IN FACT EXTENDED SOUTHWARD THE SLIGHT RISK INTO
THE CWA...ALONG AND NORTH OF A LINE FROM JUST NORTH OF LAREDO TO
ALICE TO VICTORIA. IF CONVECTION DOES DEVELOP OVER OR INTO THE CWA
IT SHOULD DIMINISH LATE IN EVENING WITH LOSS OF HEATING. SLIGHTLY
COOLER TONIGHT...WITH WINDS BACKED EAST AND NORTHEAST. PATCHY TO
AREAS OF FOG DEVELOPING OVERNIGHT. SLIGHTLY COOLER (BUT STILL
WARM) ON MONDAY ACROSS SOUTH TEXAS. ECMWF INDICATING QPF ACROSS
THE RIO GRANDE PLAINS AND EDWARDS PLATEAU ON MONDAY...WHERE PWATS
STILL POOLED NEAR 1.5"...BUT AM KEEPING FORECAST DRY DUE TO LOW
CONFIDENCE.
LONG TERM (MONDAY THROUGH SATURDAY)...CHALLENGING FORECAST
CONTINUES THROUGH THE EXTENDED...HOWEVER EACH NEW MODEL RUN BRINGS
THE DIFFERENT GUIDANCE OPTIONS CLOSER TOGETHER...WELL...EXCEPT FOR
THE NAM...WHICH IS A PRETTY FAR OUTLIER. WILL FOCUS MAINLY TOWARD
THE GFS AND ECMWF THROUGHOUT THE FORECAST. THESE HAVE COME IN QUITE
GOOD AGREEMENT WITH FRONTAL PASSAGE TIMING BEING WEDNESDAY
AFTERNOON. (THE NAM MUCH FASTER THAN THIS...AND THE CANADIAN A BIT
SLOWER.) TOUGH PART OF THE FORECAST IS PRECIP TIMING AND AMOUNTS.
COULD SEE SOME ISOLATED ACTIVITY BY MONDAY NIGHT...BUT BETTER
CHANCES BEGIN ON TUESDAY. WITH FAVORABLE ISENTROPIC LIFT PATTERN
SETTING UP...AND PLENTY OF MOISTURE POOLING ACROSS THE AREA...SEEMS
A GOOD CHANCE FOR A WIDESPREAD RAIN ACROSS SOUTH TEXAS. WITH A
SUFFICIENTLY WEAKENED CAP WILL HAVE THE POTENTIAL FOR THUNDERSTORMS
TUESDAY AND WEDNESDAY. ONE THING NOTABLE SEPARATING THIS EVENT FROM
OTHER FRONTS/PRECIP CHANCES WE/VE HAD RECENTLY...WINDS IN THE LOWER
LEVELS OF THE ATMOSPHERE STAY SOUTHEAST OR SOUTH THROUGH TUESDAY
BEFORE VEERING SOUTHWEST WEDNESDAY MORNING. THIS WOULD ALLOW FOR A
MOIST/SATURATED LAYER UP TO AROUND 850MB. HAVE NOT MADE MUCH CHANGE
TO PREVIOUS POP FORECAST...MAXING OUT AT 70 POPS ON TUESDAY NIGHT
AND EARLY WEDNESDAY...THEN TRAILING OFF WEDNESDAY NIGHT. UNLESS
FRONTAL TIMING BACKS UP FURTHER...THINK PRECIP SHOULD BE DONE BY
SUNRISE THURSDAY AS UPPER LOW/TROUGH LIFTS OUT OF THE AREA. TOUGH TO
MAKE A SPECIFIC CALL ON PRECIP TOTALS AT THIS TIME...BUT CERTAINLY
HAVE THE POTENTIAL FOR AN INCH OR MORE OF RAIN FOR SOME OF US...BEST
CHANCES BEING THE NORTHEAST PORTION OF THE FORECAST AREA. CURRENTLY
HAVE A GENERALLY RANGE OF ONE HALF TO ONE INCH ACROSS THE CWA.
AS FAR AS TEMPERATURES...WARMED THINGS UP A BIT ON WEDNESDAY WITH
FRONT NOT COMING THROUGH UNTIL THE AFTERNOON...HOWEVER WITH NEARLY
OVERCAST SKIES AND PRECIP IN THE AREA WILL BE SEVERAL DEGREES COOLER
THAN TUESDAY. WILL ONLY REALLY SEE ONE DAY OF NORTHERLY WINDS/COLD
ADVECTION BEHIND THE FRONT BEFORE HIGH PRESSURE RIDGE PUSHES OFF TO
THE EAST BY FRIDAY. THUS A COOL DAY ON THURSDAY...BUT GRADUALLY
WARMING TEMPS FRIDAY INTO THE WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 87 64 85 68 81 / 10 10 10 10 40
VICTORIA 83 61 83 65 78 / 20 20 10 20 50
LAREDO 94 68 89 68 86 / 10 10 10 20 40
ALICE 91 64 89 68 82 / 10 10 10 10 40
ROCKPORT 78 64 77 66 77 / 10 10 10 20 40
COTULLA 89 64 88 67 84 / 20 30 10 20 50
KINGSVILLE 89 64 86 67 83 / 10 10 10 10 40
NAVY CORPUS 81 66 79 68 79 / 10 10 10 10 40
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...SHORT TERM
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1019 AM MDT SUN MAR 31 2013
.UPDATE...WEAKENING UPPER LEVEL RIDGE WILL PASS ACROSS COLORADO
TODAY. THIS WILL KEEP SKIES MOSTLY SUNNY THROUGH THE DAY. MADE
SMALL TWEAKS TO THE SKY TO REFLECT THIS. TEMPERATURES APPEAR ON
TRACK AND NO OTHER UPDATES ARE PLANNED AT THIS TIME.
&&
.AVIATION...SOUTHERLY WINDS WILL TURN WEST TO NORTHWEST AFTER
18Z. A WEAK COLD FRONT WILL CAUSE WINDS TO SHIFT NORTHEASTERLY
TONIGHT AT SPEEDS UNDER 20 KNOTS. MOSTLY CLEAR SKIES WILL PREVAIL
THROUGH THE DAY. HIGH CLOUDS WILL INCREASE OVERNIGHT. A LAYER OF
STRATUS MAY DEVELOP MONDAY MORNING AROUND 12Z WITH CEILINGS IN THE
2000 TO 3000 FEET RANGE.
&&
.PREV DISCUSSION... /ISSUED 240 AM MDT SUN MAR 31 2013/
SHORT TERM...GENERALLY DRY NW FLOW WILL BE OVER THE AREA THRU
THIS AFTN AS SFC LOW PRES DEVELOPS OVER ERN CO. 850-700 MB TEMPS
ARE A DEGREE OR TWO WARMER THIS AFTN SO WILL KEEP HIGHS IN THE 65
TO 70 DEGREE RANGE OVER NERN CO.
FOR TONIGHT THE FLOW ALOFT WILL BECOME MORE WSW AS A WEAK UPPER
LEVEL LOW BEGINS TO MOVE TOWARDS THE GREAT BASIN. SOME MOISTURE
WILL INCREASE IN THE MTNS LATE TONIGHT SO WILL MENTION A SLIGHT
CHC OF -SHSN WEST OF THE DIVIDE AFTER MIDNIGHT. OVER NERN CO A
CDFNT WILL BACKDOOR INTO THE AREA OVERNIGHT HOWEVER OUTSIDE OF
SOME INCREASE IN LOW LVL CLOUDS AT THIS TIME DO NOT EXPECT ANY
PCPN.
LONG TERM...MODELS SLOWER WITH WEAK UPPER LOW. NOW ITS OVER THE
FOUR CORNERS FROM 18Z TO 00Z TUESDAY AFTERNOON. IT WEAKENS AND
BECOMES AN OPEN TROUGH...ITS AXIS IS OVER EASTERN COLORADO AT 12Z
WEDNESDAY MORNING. THE FLOW ALOFT IS PRETTY WEAK ACROSS THE CWA
FROM MONDAY NIGHT THROUGH TUESDAY NIGHT. THERE IS UPWARD SYNOPTIC
SCALE ENERGY PROGGED FOR THE CWA MONDAY THROUGH TUESDAY NIGHT. THE
BOUNDARY LAYER FLOW IS PROGGED TO BE UPSLOPE MONDAY THROUGH MUCH
OF TUESDAY NIGHT...WITH EITHER EAST OR SOUTHEAST DIRECTIONS. THE
MOISTURE IS NOT AS EXTENSIVE AND PROLONGED AS PREVIOUS MODEL RUNS
INDICATED. THE QPF FIELDS DO NOT START MEASURABLE PRECIPITATION
UNTIL LATER MONDAY MORNING. MODELS SHOW MEASURABLE PRECIPITATION
INTO WEDNESDAY MORNING NOW. THE AMOUNTS ARE LESS THAN YESTERDAY`S
00Z RUNS INDICATED. SO RATHER THAN CHASING THE LATEST/GREATEST
MODELS AND AT THE RISK OF CONTINUING TO YO-YO THE FORECAST...WILL
CHANGE VERY LITTLE THROUGH TUESDAY NIGHT. TEMPERATURES LOOK
CONSIDERABLY WARMER ON MONDAY THAN YESTERDAY`S 00Z RUNS INDICATED.
MONDAY`S HIGHS ARE NOW ONLY 4-7 COOLER THAN SUNDAY`S HIGHS.
TUESDAY`S HIGHS ARE 1-3 C COOLER THAN MONDAY`S. AGAIN WILL LEAVE
THINGS STATUS QUO THIS UPDATE. FOR THE LATER DAYS...WEDNESDAY
THROUGH SATURDAY...THERE IS UPPER RIDGING INTO FRIDAY MORNING
..THEN A WEAK UPPER TROUGH MOVES ACROSS FRIDAY NIGHT...AND
MORE RIDGING SATURDAY.
AVIATION...LIGHT DRAINAGE WINDS THRU THE MORNING HOURS WILL
BECOME NWLY BY EARLY AFTN. LATEST RAP SHOWS WINDS COULD GUSTY UP
TO 20 MPH FOR A FEW HOURS BETWEEN 22Z AND 00Z BEFORE DECREASING.
TONIGHT A CDFNT WILL BACKDOOR INTO THE AREA BETWEEN 03Z AND 06Z
WITH WINDS BECOMING MORE NELY. AFTER 06Z WINDS WILL SHIFT TO LIGHT
ESE. TOWARDS 12Z MAY SEE SOME STRATUS WITH CEILINGS IN THE
2000-3000 FT RANGE.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM....RJK
UPDATE/AVIATION...MEIER
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
353 PM EDT SUN MAR 31 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE INTO THE FORECAST AREA TONIGHT...BRINGING
INCREASED CHANCES OF RAIN. A DRY REINFORCING COLD FRONT WILL MOVE
THROUGH THE AREA MONDAY NIGHT AND STALL JUST TO OUR SOUTH TUESDAY.
CHANCES OF RAIN INCREASE AGAIN LATE IN THE WEEK AS ANOTHER SYSTEM
APPROACHES FROM THE WEST.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
RADAR CURRENTLY INDICATES A BAND OF SCATTERED SHOWERS PUSHING
EAST TOWARDS THE CSRA. LATEST RUC TAKES THIS ACTIVITY EAST ACROSS
THE FORECAST AREA (FA) OVER THE NEXT FEW HOURS. THEN...POPS AND
COVERAGE WILL INCREASE LATER TONIGHT AS A COLD FRONT DRIVEN BY AN
UPPER SHORTWAVE PUSHES INTO THE REGION. PRECIPITABLE WATER VALUES
CURRENTLY BELOW AN INCH WILL RISE TO NEAR 1.3 INCHES JUST AHEAD OF
THE FRONT WITH A 30-40 KT LOW LEVEL JET SUPPORTING MOISTURE
TRANSPORT INTO THE AREA. WILL INCREASE POPS TO HIGH LIKELY.
SEVERE POTENTIAL SEEMS WEAK BUT CANNOT BE RULED OUT AS THERE IS
SOME WEAK INSTABILITY AND SHEAR IS MODERATE...BUT WITH THE LOSS OF
HEATING THINK ANY SEVERE THREAT WOULD BE ISOLATED AND LIMITED TO
THE SOUTHERN PART OF THE FORECAST AREA. SPC HAS THE AREA OUTLOOKED
IN GENERAL THUNDER. TEMPERATURES WILL BE SLOW TO FALL OVERNIGHT
DUE TO CLOUD COVER...PRECIPITATION AND WINDS STAYING UP A BIT.
OVERNIGHT LOWS SHOULD BE ABOVE NORMAL WELL IN THE 50S.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
MONDAY...MODELS SHOW WEAK SHORT WAVE MOVING THROUGH REGION LATE
TONIGHT THROUGH MONDAY MORNING. WILL CARRY HIGHEST POPS DURING
THIS PERIOD WITH 50-60 PERCENT CHANCE MONDAY MORNING...DROPPING
TO 20-30 PERCENT BY MONDAY AFTERNOON. WEAK WARM FRONT THAT MOVED
NORTHWARD SUNDAY IS EXPECTED TO BE PICKED UP BY THE SHORT WAVE
AND MOVED EAST DURING THE DAY MONDAY. WESTERLY WINDS 5-10 KNOTS
BEHIND THE FRONT SHOULD BRING DRIER AIR TO THE REGION. THIS WILL
BE REFLECTED BY LOWER POPS MONDAY AFTERNOON. NOT MUCH IN THE WAY
OF COLD AIR ADVECTION BEHIND WEAK COLD FRONT MONDAY. WITH SUNSHINE
MONDAY AFTERNOON...HIGH TEMPERATURES ARE EXPECTED TO RISE INTO
THE MIDDLE TO UPPER 70S. THIS WILL HELP THE ATMOSPHERE TO BECOME
MORE UNSTABLE ESPECIALLY BY EARLY MONDAY AFTERNOON. STILL A MENTION
OF SHOWERS AT THIS TIME. AND WITH STABILITY PARAMETERS SHOWING
LIS -1/-2...TOTALS NEAR 45...PW VALUES NEAR 1 INCH AND CAPES NEAR
600 J/KG...THERE MAY BE A FEW THUNDERSTORMS AROUND. HOWEVER...
WITH WEAK INSTABILITY...DO NOT EXPECT ANY STRONG OR SEVERE STORMS
TO DEVELOP. ACTUALLY...SPC JUST HAS A GENERAL THUNDERSTORM AREA
OVER THE SOUTHERN PART OF THE FORECAST AREA. AFTER 18Z MONDAY
AFTERNOON...THERE IS ADDITIONAL DRYING WITH PW VALUES DROPPING
TO AROUND 0.70 OF AN INCH AND A WEAK MID LEVEL CAP.
MONDAY EVENING...A BETTER DEFINED COLD FRONT DROPS TO THE SOUTH
WITH AT LEAST A TEMPERATURE GRADIENT. IT HAS SOME MOISTURE AT
FIRST BUT LOSES JUST ABOUT ALL THE MOISTURE AS IN MOVES ACROSS
THE APPALACHIAN MOUNTAINS IN NORTH CAROLINA. SO THE FRONT WILL
MOVE THROUGH MONDAY NIGHT DRY. COOLER MONDAY NIGHT WITH LOWS
IN THE MIDDLE TO UPPER 40S.
TUESDAY AND TUESDAY NIGHT...HIGH PRESSURE WITH COOLER DRIER AIR.
HIGHS MAINLY IN THE MIDDLE 60S WITH LOWS TUESDAY NIGHT MAINLY
IN THE MIDDLE 40S. THERE MAY BE SOME INCREASE IN HIGH AND MID
LEVEL CLOUDINESS LATE TUESDAY NIGHT AS A NEW WEATHER SYSTEM
BEGINS TO APPROACH FROM THE WEST.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
MEDIUM RANGE MODELS IN GOOD AGREEMENT AT LEAST EARLY IN THE
EXTENDER PERIOD WEDNESDAY. MODELS THEN BRING A SYSTEM OUT OF
THE GULF OF MEXICO THURSDAY AND FRIDAY. THE GFS HAS A STRONGER
SYSTEM AND MORE PROGRESSIVE SYSTEM BUT BOTH THE GFS AND ECMWF
BRING THE LOW UP THE CAROLINA COAST. A WEDGE PATTERN IS EXPECTED
THURSDAY. AS THE SYSTEM MOVES FARTHER TO THE NORTHEAST...COLD
AIR ADVECTION WITH NORTHERLY WINDS AND WRAP AROUND MOISTURE
ARE EXPECTED ON FRIDAY. THE SYSTEM IS GONE BY THE WEEKEND AND
HIGH PRESSURE AND DRIER AIR FOR THE WEEKEND. TEMPERATURES ARE
EXPECTED TO BE WELL BELOW NORMAL FOR MOST OF THE PERIOD EXCEPT
MAYBE RETURNING TO CLOSE TO NORMAL BY SUNDAY. WILL HAVE THURSDAY
AS THE COOLEST DAY WITH A WEDGE AND HIGHS MAINLY IN THE LOWER
50S. DEPENDING ON ANY EVAPORATIVE COOLING WITH THE RAINFALL...
THURSDAY MAY BE COOLER. FRIDAY IS STILL FAIRLY COOL WITH HIGHS
IN THE UPPER 50S. WITH THE RETURN OF SUNSHINE...THE WEEKEND
PROMISES TO BE WARMER. HIGHS IN THE MIDDLE 60S SATURDAY AND
HIGHS AROUND 70 SUNDAY. OVERNIGHT LOWS SHOULD BE MOSTLY IN THE
40S FOR MUCH OF THE EXTENDED PERIOD.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
VFR CONDITIONS EXPECTED THROUGH THIS EVENING...FOLLOWED BY
DETERIORATING CONDITIONS LATER TONIGHT AND MONDAY MORNING. SCATTERED
SHOWERS DEVELOPING WITH DAYTIME HEATING AND WARM ADVECTION WILL
AFFECT THE MIDLANDS AND CSRA. COULD SEE MVFR OR LOWER CONDITIONS IN
SHOWERS...BUT PROBABILITY AND CONFIDENCE TOO LOW TO INCLUDE AT THIS
TIME. WILL AMEND TAFS AS NEEDED.
A COLD FRONT WILL MOVE INTO THE AREA OVERNIGHT...SO EXPECT
WIDESPREAD RAIN TO OVERSPREAD THE TERMINALS BEGINNING AROUND 05Z
WITH DETERIORATING MVFR/IFR CONDITIONS WHICH SHOULD HOLD THROUGH
AROUND 15Z. THUNDERSTORMS CANNOT BE RULED OUT BUT CONFIDENCE IS NOT
HIGH ENOUGH TO INCLUDE IN FORECAST. WINDS WILL REMAIN SOUTHWESTERLY
AROUND 10-15 MPH WITH GUSTS TO 25 MPH LATE THIS AFTERNOON...THEN
DECREASING OVERNIGHT AND SHIFTING TO THE WEST BY 12Z.
EXTENDED AVIATION OUTLOOK...NO RESTRICTIONS TO AVIATION EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
352 PM EDT SUN MAR 31 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE INTO THE FORECAST AREA TONIGHT...BRINGING
INCREASED CHANCES OF RAIN. A DRY REINFORCING COLD FRONT WILL MOVE
THROUGH THE AREA MONDAY NIGHT AND STALL JUST TO OUR SOUTH TUESDAY.
CHANCES OF RAIN INCREASE AGAIN LATE IN THE WEEK AS ANOTHER SYSTEM
APPROACHES FROM THE WEST.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
RADAR CURRENTLY INDICATES A BAND OF SCATTERED SHOWERS PUSHING
EAST TOWARDS THE CSRA. LATEST RUC TAKES THIS ACTIVITY EAST ACROSS
THE FORECAST AREA (FA) OVER THE NEXT FEW HOURS. THEN...POPS AND
COVERAGE WILL INCREASE LATER TONIGHT AS A COLD FRONT DRIVEN BY AN
UPPER SHORTWAVE PUSHES INTO THE REGION. PRECIPITABLE WATER VALUES
CURRENTLY BELOW AN INCH WILL RISE TO NEAR 1.3 INCHES JUST AHEAD OF
THE FRONT WITH A 30-40 KT LOW LEVEL JET SUPPORTING MOISTURE
TRANSPORT INTO THE AREA. WILL INCREASE POPS TO HIGH LIKELY.
SEVERE POTENTIAL SEEMS WEAK BUT CANNOT BE RULED OUT AS THERE IS
SOME WEAK INSTABILITY AND SHEAR IS MODERATE...BUT WITH THE LOSS OF
HEATING THINK ANY SEVERE THREAT WOULD BE ISOLATED AND LIMITED TO
THE SOUTHERN PART OF THE FORECAST AREA. SPC HAS THE AREA OUTLOOKED
IN GENERAL THUNDER. TEMPERATURES WILL BE SLOW TO FALL OVERNIGHT
DUE TO CLOUD COVER...PRECIPITATION AND WINDS STAYING UP A BIT.
OVERNIGHT LOWS SHOULD BE ABOVE NORMAL WELL IN THE 50S.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
MONDAY...MODELS SHOW WEAK SHORT WAVE MOVING THROUGH REGION LATE
TONIGHT THROUGH MONDAY MORNING. WILL CARRY HIGHEST POPS DURING
THIS PERIOD WITH 50-60 PERCENT CHANCE MONDAY MORNING...DROPPING
TO 20-30 PERCENT BY MONDAY AFTERNOON. WEAK WARM FRONT THAT MOVED
NORTHWARD SUNDAY IS EXPECTED TO BE PICKED UP BY THE SHORT WAVE
AND MOVED EAST DURING THE DAY MONDAY. WESTERLY WINDS 5-10 KNOTS
BEHIND THE FRONT SHOULD BRING DRIER AIR TO THE REGION. THIS WILL
BE REFLECTED BY LOWER POPS MONDAY AFTERNOON. NOT MUCH IN THE WAY
OF COLD AIR ADVECTION BEHIND WEAK COLD FRONT MONDAY. WITH SUNSHINE
MONDAY AFTERNOON...HIGH TEMPERATURES ARE EXPECTED TO RISE INTO
THE MIDDLE TO UPPER 70S. THIS WILL HELP THE ATMOSPHERE TO BECOME
MORE UNSTABLE ESPECIALLY BY EARLY MONDAY AFTERNOON. STILL A MENTION
OF SHOWERS AT THIS TIME. AND WITH STABILITY PARAMETERS SHOWING
LIS -1/-2...TOTALS NEAR 45...PW VALUES NEAR 1 INCH AND CAPES NEAR
600 J/KG...THERE MAY BE A FEW THUNDERSTORMS AROUND. HOWEVER...
WITH WEAK INSTABILITY...DO NOT EXPECT ANY STRONG OR SEVERE STORMS
TO DEVELOP. ACTUALLY...SPC JUST HAS A GENERAL THUNDERSTORM AREA
OVER THE SOUTHERN PART OF THE FORECAST AREA. AFTER 18Z MONDAY
AFTERNOON...THERE IS ADDITIONAL DRYING WITH PW VALUES DROPPING
TO AROUND 0.70 OF AN INCH AND A WEAK MID LEVEL CAP.
MONDAY EVENING...A BETTER DEFINED COLD FRONT DROPS TO THE SOUTH
WITH AT LEAST A TEMPERATURE GRADIENT. IT HAS SOME MOISTURE AT
FIRST BUT LOSES JUST ABOUT ALL THE MOISTURE AS IN MOVES ACROSS
THE APPALACHIAN MOUNTAINS IN NORTH CAROLINA. SO THE FRONT WILL
MOVE THROUGH MONDAY NIGHT DRY. COOLER MONDAY NIGHT WITH LOWS
IN THE MIDDLE TO UPPER 40S.
TUESDAY AND TUESDAY NIGHT...HIGH PRESSURE WITH COOLER DRIER AIR.
HIGHS MAINLY IN THE MIDDLE 60S WITH LOWS TUESDAY NIGHT MAINLY
IN THE MIDDLE 40S. THERE MAY BE SOME INCREASE IN HIGH AND MID
LEVEL CLOUDINESS LATE TUESDAY NIGHT AS A NEW WEATHER SYSTEM
BEGINS TO APPROACH FROM THE WEST.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
MEDIUM RANGE MODELS IN GOOD AGREEMENT AT LEAST EARLY IN THE
EXTENDER PERIOD WEDNESDAY. MODELS THEN BRING A SYSTEM OUT OF
THE GULF OF MEXICO THURSDAY AND FRIDAY. THE GFS HAS A STRONGER
SYSTEM AND MORE PROGRESSIVE SYSTEM BUT BOTH THE GFS AND ECMWF
BRING THE LOW UP THE CAROLINA COAST. A WEDGE PATTERN IS EXPECTED
THURSDAY. AS THE SYSTEM MOVES FARTHER TO THE NORTHEAST...COLD
AIR ADVECTION WITH NORTHERLY WINDS AND WRAP AROUND MOISTURE
ARE EXPECTED ON FRIDAY. THE SYSTEM IS GONE BY THE WEEKEND AND
HIGH PRESSURE AND DRIER AIR FOR THE WEEKEND. TEMPERATURES ARE
EXPECTED TO BE WELL BELOW NORMAL FOR MOST OF THE PERIOD EXCEPT
MAYBE RETURNING TO CLOSE TO NORMAL BY SUNDAY. WILL HAVE THURSDAY
AS THE COOLEST DAY WITH A WEDGE AND HIGHS MAINLY IN THE LOWER
50S. DEPENDING ON ANY EVAPORATIVE COOLING WITH THE RAINFALL...
THURSDAY MAY BE COOLER. FRIDAY IS STILL FAIRLY COOL WITH HIGHS
IN THE UPPER 50S. WITH THE RETURN OF SUNSHINE...THE WEEKEND
PROMISES TO BE WARMER. HIGHS IN THE MIDDLE 60S SATURDAY AND
HIGHS AROUND 70 SUNDAY. OVERNIGHT LOWS SHOULD BE MOSTLY IN THE
40S FOR MUCH OF THE EXTENDED PERIOD.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
135 PM EDT SUN MAR 31 2013
.UPDATE...
/ISSUED AT 1022 AM EDT SUN MAR 31 2013/
A FEW SHOWERS LINGER OVER TOOMBS COUNTY BUT THESE ARE MOVING QUICKLY
TO THE EAST. AN AREA OF SHOWERS AND ISOLATED TSTORMS OVER CENTRAL AL
IS HOLDING TOGETHER AND SHOULD MOVE INTO WEST CENTRAL GA AROUND
NOON. MODELS NOT HANDLING THIS AS WELL...ALTHOUGH THE HRRR DOES HAVE
THE AREA OF SHOWERS BUT TOO FAR NORTH. THE 2ND WAVE OVER OK/AR STILL
PROGGED TO MOVE INTO THE CWA LATE THIS AFTERNOON/THIS EVENING. TEMPS
STILL LOOK ON TARGET. EVEN WITH THE CLOUDS THERE IS STILL SOME GOOD
WAA TODAY. OTHER THAN ADJUSTING THE POPS...NO OTHER CHANGES PLANNED.
&&
.SHORT TERM /TODAY THROUGH MONDAY/...
/ISSUED AT 740 AM EDT SUN MAR 31 2013/
SHORT WAVE CURRENTLY MOVING THROUGH OHIO/TN VALLEY AREA. SHOWERS
ASSOCIATED WITH THIS FEATURE WILL CONTINUE TO MOVE EAST THROUGH THE
CWA THIS MORNING. SHOWERS SHOULD DIMINISH THROUGH THE MORNING AND
MODELS INDICATE A BREAK BETWEEN THIS WAVE AND THE NEXT ONE WHICH
SHOULD AFFECT US STARTING THIS AFTERNOON. HAVE INCREASED POPS AGAIN
STARTING AROUND 18Z AND CONTINUE WITH LIKELY POPS FOR MUCH OF THE
CWA THROUGH 06Z MONDAY. INSTABILITY INCREASES ALSO DURING THIS
AFTERNOON WITH BEST CAPE AND LIFTED INDEX VALUES 18Z TODAY THROUGH
06Z MONDAY. HAVE CONTINUED WITH MENTION OF THUNDER DURING THAT TIME.
UPPER TROUGH DEEPENING OVER THE NORTHERN STATES SHOULD PUSH A
SURFACE BOUNDARY INTO NORTH GA LATE TONIGHT AND INTO MONDAY. SOME
DRYING SHOULD OCCUR BEHIND THIS BOUNDARY AND HAVE ENDED SHOWERS FROM
THE NORTH MONDAY MORNING WITH SOME POPS CONTINUING THROUGH THE
CENTRAL ZONES INTO THE AFTERNOON. TEMPERATURES CONTINUE WARM THROUGH
THE SHORT TERM AND HAVE TAKEN A BLEND OF THE MAV/MET.
41
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
/ISSUED AT 740 AM EDT SUN MAR 31 2013/
NEXT MAIN RAIN EVENT WILL ENCOMPASS THE SECOND HALF OF THE WEEK.
GFS/EUROPEAN SIMILAR WITH BRINGING RAIN TO THE AREA POSSIBLY AS
EARLY AS TUESDAY NIGHT/WEDNESDAY BUT MORE SO WEDNESDAY NIGHT INTO
FRIDAY. A WARM FRONT DEVELOPS ALONG THE GULF COAST WITH OVERRUNNING
MOIST FLOW SETTING UP. THE MAIN DIFFERENCE BETWEEN THE GFS AND
EUROPEAN IS THE EUROPEAN BRINGS SURFACE LOW PRESSURE ACROSS CENTRAL
TO S GA THURSDAY NIGHT AND FRIDAY WHILE THE GFS TAKES THE SURFACE
LOW ACROSS N FL. GFS BRINGS ONLY MINIMAL MUCAPE INTO CENTRAL GA
THURSDAY/THURSDAY NIGHT. IF THE EUROPEAN SURFACE SOLUTION COMES TO
PASS THE CHANCES FOR THUNDERSTORMS WOULD BE GREATER WITH THE WARM
FRONT POSSIBLY GETTING INTO CENTRAL GA WITH A LOW END THREAT FOR
SEVERE WEATHER. EITHER WAY A GOOD RAIN EVENT WITH 1 TO 2 INCHES
ACROSS CENTRAL GA. THE UPPER TROUGH MOVES TO THE AREA FRIDAY
WITH THE GFS A LITTLE FASTER WITH THE TROUGH AND MOISTURE EXITING
THAN THE EUROPEAN. A DAMPENING SHORT WAVE RIDGE AND SURFACE HIGH
PRESSURE MOVE TO THE AREA SATURDAY WITH DRY CONDITIONS EXPECTED
AND THIS LOOKS TO CONTINUE FOR SUNDAY.
BDL
&&
.AVIATION...
18Z UPDATE...
SCATTERED SHOWERS REMAINING FROM THIS MORNINGS CONVECTION OVER
ALABAMA WILL CONTINUE ACROSS THE FORECAST AREA THIS AFTERNOON. AS
SURFACE HEATING INCREASES LATE THIS AFTERNOON...ISOLATED TSRA WILL
DEVELOP. THE NEXT SHORT WAVE WILL MOVE INTO THE AREA THIS EVENING
BRINGING SHOWERS AND SCATTERED THUNDERSTORMS. PRECIP WILL END FROM
THE NORTH AFTER MIDNIGHT. PLENTY OF LOW LEVEL MOISTURE TONIGHT WILL
KEEP CIGS BELOW 1000 FT MOST AREAS. CIGS WILL RISE TO VFR BY 18Z MON
ALL AREAS AND REMAIN VFR THROUGH MONDAY AFTERNOON. SOUTHWEST WINDS
WILL BECOME LIGHT THIS EVENING...THEN NORTHWEST AFTER FROPA LATE
TONIGHT. WIND SPEEDS WILL INCREASE MONDAY MORNING WITH GUSTS TO 15
TO 20KTS MONDAY AFTERNOON.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ALL ELEMENTS.
17
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 53 75 46 / 40 60 10 10
ATLANTA 70 54 73 50 / 50 60 10 10
BLAIRSVILLE 63 47 69 39 / 50 60 10 20
CARTERSVILLE 69 50 72 43 / 60 60 10 10
COLUMBUS 76 58 77 52 / 50 70 30 5
GAINESVILLE 69 51 74 47 / 40 60 10 10
MACON 76 57 77 48 / 40 70 30 5
ROME 70 50 73 43 / 60 60 10 20
PEACHTREE CITY 71 52 74 45 / 50 60 10 5
VIDALIA 78 60 77 53 / 30 70 60 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...41
LONG TERM....BDL
AVIATION...41
AREA FORECAST DISCUSSION...UPDATED
NWS PADUCAH KY
1225 PM CDT SUN MAR 31 2013
.UPDATE...
ISSUED AT 1221 PM CDT SUN MAR 31 2013
UPDATED THE AVIATION SECTION FOR THE 18Z TAF ISSUANCE.
&&
UPDATE ISSUED AT 701 AM CDT SUN MAR 31 2013
LATEST RADAR TRENDS SHOW ANY THUNDER THREAT GETTING SHUNTED TO OUR
WEST AND SOUTHWEST. THE FRESHEST DEVELOPMENT IS IN NORTHERN
ARKANSAS...WHICH MAY SPELL A RAPID END TO THE MISSOURI CONVECTION
EARLY THIS MORNING. SOME SHORT TERM GUIDANCE PUSHES THE NORTHERN
ARKANSAS CONVECTION MORE TO THE EAST...POTENTIALLY IMPACTING OUR
ENTIRE SOUTHERN BORDER WITH TIME THROUGH THE DAY.
BEST GUESS IS THAT AREAS ALONG AND WEST OF A LINE FROM MARBLE HILL
MISSOURI TO FULTON KENTUCKY LINE COULD SEE SOME TANGIBLE SHOWERS
THIS MORNING. UPDATED TO BRING CHANCE POPS SOUTHEAST ACROSS THIS
AREA THROUGH THE MORNING. AREAS NEAR THE TENNESSEE BORDER COULD
SEE A STRAY SHOWER EARLY THIS AFTERNOON.
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 12Z TAF ISSUANCE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 406 AM CDT SUN MAR 31 2013
CONSIDERED A DENSE FOG ADVISORY FOR WESTERN PORTIONS OF SOUTHEAST
MISSOURI DUE TO KPOF REPORTING 1/2 MILE OR LESS...BUT IT SEEMS TO
BE IMPROVING A BIT IN THE LAST HOUR AND WE HAVE LITTLE CLUE HOW
WIDESPREAD IT IS. WILL KEEP AN EYE ON IT...BUT FOR NOW WILL JUST
LET IT BE.
WEAK ECHOES FOR LIGHT RAIN HAVE JUST ABOUT PUSHED EAST OF THE
EVANSVILLE TRI STATE...BUT THERE MAY BE JUST A BIT LINGERING IN
THE KOWB AREA. THIS SHOULD COME TO AN END SHORTLY. OF GREATER
CONCERN IS THE AREA OF SHOWERS AND THUNDERSTORMS MOVING EAST
SOUTHEAST ACROSS EASTERN KANSAS AND WEST CENTRAL MISSOURI.
HAD TO LEAN ON THE HRRR MODEL SIMULATED REFLECTIVITY TO REPRESENT
THIS IN THE GRIDS. IN GENERAL WOULD EXPECT THE AREA TO WEAKEN AS
IT MOVES INTO OUR REGION JUST AFTER SUNRISE...SO WILL HAVE 20-30
POPS FOR NOW...GENERALLY SWEEPING ACROSS OUR SOUTHWEST HALF 14Z-
20Z. THIS WEAKENING TREND IS SUPPORTED BY THE 06Z NAM...WHICH
KEEPS ANY INSTABILITY TO OUR WEST AND SOUTHWEST. WILL HAVE TO KEEP
A CLOSE EYE ON THIS SITUATION AS WELL AND BE PREPARED TO UPDATE
IF/WHEN IT BECOMES NECESSARY.
TEMPERATURES EARLY THIS MORNING ARE NEARLY STEADY...SO WE WILL
HAVE A MILD START TO THE DAY...WHICH IS GOOD BECAUSE THE LOW
CLOUDS/FOG AND EVENTUALLY SOME SHOWERS WILL DELAY WARMING THROUGH
THE MORNING. TRIED TO CAPTURE THIS TREND IN THE TEMPERATURE
GRIDS...BUT WE SHOULD JUMP UP WELL INTO THE 60S WITH SOME SUNSHINE
THIS AFTERNOON. STAYED CLOSE TO CONSENSUS.
LIKE THE 00Z AND 06Z NAM WITH THE REAL COLD FRONT/SURFACE HIGH
SURGE THROUGH THE AREA LATE TONIGHT AND MONDAY...AS IT SHOULD
HANDLE THE SHALLOW COLD AIRMASS BETTER THAN THE LESSER RESOLVED
GFS. THE NAM DOES GENERATE SOME VERY MEAGER QPF OVER THE
EVANSVILLE TRI STATE TONIGHT WITH THE INITIAL WIND SHIFT...BUT THE
GFS IS DRY. DECIDED TO MENTION SOME SPRINKLES IN THAT AREA THROUGH
THE NIGHT...BUT DID NOT INTRODUCE A MEASURABLE POP. CONSENSUS OF
GUIDANCE SEEMS TO HAVE A GOOD HANDLE ON TEMPERATURES TONIGHT.
TEMPERATURES ONLY FALL INTO THE UPPER 30S IN THE NORTH...SO LITTLE
CHANCE OF FLURRIES WITH THE SPRINKLES TONIGHT.
FOR MONDAY...THE MODELS CONTINUE TO TREND DRIER AND DRIER FOR OUR
AREA. SIMILAR TO TONIGHT...DECIDED TO JUST PLASTER A CHANCE OF
SPRINKLES ACROSS THE ENTIRE AREA THROUGH THE DAY...IN LIEU OF A
VERY SMALL MEASURABLE POP. TEMPERATURES WILL SUPPORT ALL LIQUID
THROUGH THE DAY. FIGURE WITH THE SURGE CONSISTENTLY ADVERTISED IN
THE NAM RUNS...THAT TEMPERATURES WILL BE COOLER THAN MOST GUIDANCE
INDICATES. STAYED ON THE LOW SIDE OF GUIDANCE CLOSER TO THE
NAM/MET...BUT THAT MAY NOT BE COOL ENOUGH.
MONDAY NIGHT WILL BE DRY...BUT WE WILL REMAIN IN CYCLONIC WEST
NORTHWEST FLOW ALOFT...SO CANNOT RULE OUT SOME LIGHT
PRECIPITATION...ESPECIALLY OVER OUR SOUTHWEST MONDAY NIGHT INTO
TUESDAY. THE GFS IS THE MOST AGGRESSIVE IN GENERATING LIGHT QPF
WITH SOME FRONTOGENETIC FORCING IN THE 850-700MB LAYER IN THE FAR
SOUTHWEST. INTRODUCED SOME VERY SMALL POPS NEAR THE ARKANSAS
BORDER AND THE BOOT HEEL REGION JUST TO BE SAFE. LATELY...IF THERE
IS ANY CHANCE OF US GETTING WET IT SEEMS TO HAPPEN. TEMPERATURES
IN THAT AREA SHOULD BE NO LOWER THAN THE MIDDLE 30S...SO KEPT THIS
ALL RAIN AS WELL. CONSENSUS TEMPERATURES LOOKED FINE MONDAY NIGHT
AND TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 406 AM CDT SUN MAR 31 2013
THIS EXTENDED PERIOD FOR THIS FORECAST ISSUANCE WILL SERVE AS THE
TRANSITION OF EXTREMES IN TEMPERATURE FROM NEAR RECORD LOWS
WEDNESDAY MORNING TO ABOVE NORMAL /MIDDLE 60S/ HIGHS NEXT WEEKEND.
GIVEN THE BELOW NORMAL TEMPERATURES WE HAVE BEEN EXPERIENCING IN
MARCH...TEMPERATURES AT OR ABOVE NORMAL WILL BE A WELCOME CHANGE.
THE ONLY WEATHER MAKER OF CONSEQUENCE WILL OCCUR THURSDAY/THURSDAY
NIGHT. ANY MEASURABLE POPS AND WEATHER /GENERALLY SLIGHT IN
CATEGORY/ WILL BE LIMITED TO WEST KENTUCKY AND A SMALL PART OF THE
SOUTHEAST MISSOURI BOOTHILL. THE SOURCE REGION FOR THIS SYSTEM IS
THE CLOSED LOW CURRENTLY OFF THE CALIFORNIA COAST. THIS FEATURE IS
EXPECTED TO PUSH TOWARD THE CENTRAL ROCKIES AND DIVE EAST-SOUTHEAST
INTO THE LOWER MISSISSIPPI VALLEY. DURING THE PAST 3-4 DAYS...THE
NORTHERN EDGE OF THIS CLOSED LOW/WAVE HAS BEEN FORECAST BY THE
GFS/ECMWF/GEM GUIDANCE TO SKIRT ALONG THE SOUTHERN BORDER OF THE WFO
PAH FORECAST AREA. THERE HAS BEEN ENOUGH MODEL RUNS TO STILL
INDICATE THAT VERY FEW LOCATIONS WILL SEE ANY RAIN...IF ANY...ON
THURSDAY. THE MAIN IMPACT WILL BE CLOUD COVER...WITH A SHARP
DEMARCATION LINE ON THE NORTHERN EDGE OF THE DEFORMATION ZONE
ASSOCIATED WITH THE LOW/WAVE. NORTHEAST WINDS DURING THIS TIME
PERIOD MAY TEMPER HIGHS SOMEWHAT.
WITH HIGH PRESSURE DOMINATING THE REGION THROUGH MOST OF THE
PERIOD...CLOUD COVER WILL BE MINIMAL OUTSIDE OF THE DISTURBANCE ON
THURSDAY. THIS WILL SET THE STAGE FOR GOOD INSOLATION/DRY AIR
ADVECTION AND EVAPORATION. A MANUAL UPWARD ADJUSTMENT WAS MADE TO
THE MAX TEMPERATURES FROM FRIDAY THROUGH SUNDAY TO ACCOUNT FOR A
LARGER DIURNAL RANGE /25-27 DEGREES F/IN TEMPERATURES WITH THE DRIER
AIR IN PLACE ACROSS THE WFO PAH FORECAST AREA.
AS A SIDE NOTE...MIN FORECAST TEMPERATURES WEDNESDAY MORNING LOOK
LIKE THEY MAY BE ONE TO TWO DEGREES HIGHER THAN THE RECORD
TEMPERATURES ON THE BOOKS. SUBTLE MICRO-CLIMATE CHANGES AROUND THE
OBSERVATION SITES WILL DETERMINE WHETHER ANY RECORDS ARE TIED OR SET
WEDNESDAY MORNING.
&&
.AVIATION...
ISSUED AT 1221 PM CDT SUN MAR 31 2013
VFR CONDITIONS EXPECTED AT KCGI/KPAH THROUGH THE PERIOD. MVFR CIGS
EARLY AT KEVV/KOWB WILL BECOME VFR BY 20-21Z. WEST TO NORTHWEST
WINDS AOB 10 KTS WILL GRADUALLY VEER AROUND TO THE NORTH BY THE
END OF THE PERIOD.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM/FIRE WX...MY
LONG TERM/AVIATION...JP
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
453 PM EDT SUN MAR 31 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 451 PM EDT SUN MAR 31 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF DEEPENING INTO THE
GREAT LAKES REGION. VIGOROUS SHORTWAVE WAS PASSING OVER LAKE
SUPERIOR. PER SATELLITE IMAGERY AND CANADIAN RADAR IMAGERY...AN
ASSOCIATED IMPRESSIVE LOOKING SMALL SWATH OF MDT TO HVY SNOW HAS
PASSED JUST N OF THE FCST AREA ACROSS FAR NRN LAKE SUPERIOR/ADJACENT
ONTARIO TODAY...ALONG/JUST N OF SHORTWAVE TRACK. AN INCREASINGLY
WELL-DEFINED SFC LOW PRES IS ORGANIZING OVER EASTERN LAKE ATTM PER
VIS SATELLITE IMAGERY. TO THE S...-SHSN TODAY HAVE DEFINITELY TAKEN
ON A SPRINGTIME DIURNAL LAND BASED LOOK WITH UNORGANIZED SCT/NMRS
COVERAGE. WELL-MIXED LAYER HAS PREVENTED SOME OF THE PCPN FROM
REACHING THE GROUND. UPSTREAM 12Z KINL SOUNDING SHOWED A DEEP
MOISTURE PROFILE TO 650MB (AROUND 11KFT)... AND MODIFYING SOUNDING
FOR A SFC T/TD IN THE LWR 30S/LWR 20S YIELDED SBCAPE AROUND
100J/KG...AND THUS THE DIURNAL COMPONENT TO THE -SHSN THIS AFTN.
MAIN FCST ISSUES TONIGHT/MON ARE POTENTIAL LES ACCUMULATIONS AS WELL
AS WINDS. FIRST UP...WINDS. EXPECT STRONGEST WINDS TO OCCUR FROM NOW
THRU THE ABOUT MID EVENING AS AREA OF 4MB/3HR PRES RISES CURRENTLY
JUST NW OF LAKE SUPERIOR SETTLES SE. THE DEEPENING INCREASINGLY
WELL-DEFINED SFC LOW OVER ERN LAKE SUPERIOR IS A CONCERN AS IT WILL
SERVE TO STRENGTHEN ISALLOBARIC WINDS. SOME OF THE HIGHER RES MODEL
GUIDANCE SEEMS TO BE PICKING UP ON THIS AS A SMALL 5-6MB/3HR PRES
RISE MAX DEVELOPS OVER CNTRL/ERN LAKE SUPERIOR WITHIN THE LARGER
SCALE PRES RISES. THE IMPACT OF THE DEEPENING LOW HAS ALREADY MADE
AN IMPACT AS WINDS HAVE GUSTED TO 50MPH AT KP59. THIS SHOULD BE A
GOOD INDICATION OF WHAT IS TO COME IN THE NEXT FEW HRS TO THE E OF
MARQUETTE. WIND ADVY HAS BEEN ISSUED FOR KEWEENAW COUNTY INTO MID
EVENING TO ACCOUNT FOR STRONG WINDS OVER THE NEXT FEW HRS.
AS FOR SNOW...NNW CYCLONIC FLOW SHOULD ALLOW SOME OF THE DEEPER
MOISTURE IN NRN ONTARIO PER 12Z CWPL SOUNDING WHICH SHOWED DEEP
MOISTURE TO 425MB (20500FT) TO SLIP INTO THE UPPER LAKES. WITH 850MB
TEMPS FALLING TO -18C BY 12Z MON...A 3KFT THICK DGZ LAYER FALLS
NICELY INTO THE CONVECTIVE LAYER WHERE NAM INDICATES RATHER VIGOROUS
UPWARD MOTION TONIGHT. WITH EQUILIBRIUM LEVELS LIKELY ABOVE 10KFT...
LES SHOULD GET GOING AT A PRETTY GOOD CLIP...BUT THE LES WILL
LIKELY TAKE SOME TIME TO GET FULLY DEVELOPED AND ORGANIZED AS THE
TYPICAL DISRUPTIVE EFFECTS OF SPRING DAYTIME HEATING ON LES WILL
NEED TO BE ERODED AWAY FIRST. ALTHOUGH IT`S NOT ESPECIALLY COLD
YET...NOTE THAT THE LAKE IS HAVING MORE OF A STABILIZING INFLUENCE
WITH LESS CLOUD OVER THE WATER THAN LAND...EXCEPT RIGHT IN THE VCNTY
OF THE SFC LOW. THE OVERNIGHT PERIOD THRU MON MORNING SHOULD BE THE
PRIME PERIOD OF LES...AND THE GOING ADVY LOOKS ON TRACK FOR THE ERN
COUNTIES ALONG LAKE SUPERIOR. WILL PROBABLY SEE SOME ACCUMULATIONS
UP TO 6-7 INCHES BY MON AFTN. CONSIDERABLE BLSN WILL ALSO BE AN
ISSUE...ESPECIALLY IN OPEN AREAS NEAR LAKE SUPERIOR. THE W WILL BE
MORE ON THE FRINGE OF THE DEEPER MOISTURE PLUS FCST SOUNDINGS SHOW
MORE OF A WELL MIXED BOUNDARY LAYER LINGERING THRU THE NIGHT WHICH
ARGUES FOR LIGHTER LES THAN OVER THE E. ACCUMULATIONS TONIGHT THRU
EARLY MON AFTN SHOULD BE IN THE 1-4 INCH RANGE OVER THE W...
INCLUDING INTO THE HIGHER TERRAIN OF NW MARQUETTE COUNTY.
CONDITIONS REMAIN FAVORABLE FOR LES MON AS 850MB TEMPS ONLY RISE A
DEGREE OR TWO IN THE AFTN. MOISTURE PROFILE REMAINS DEEP OVER THE
E...BUT DOES BECOME MORE SHALLOW OVER THE W. SO LES WILL DIMINISH
OVER THE W. EVEN OVER THE E...EXPECT LES TO BEGIN TO DIMINISH IN THE
AFTN AS STRONG DAYTIME HEATING DISRUPTS LES PROCESSES.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 451 PM EDT SUN MAR 31 2013
LAKE EFFECT WILL BE ONGOING AT THE START OF THE LONGER TERM PERIOD
ON MONDAY NIGHT. INVERSIONS 6-8KFT AND DELTA T/S AROUND 18C WITH
LAKE EQL NEARING 10KFT INDICATE NW FLOW AREAS EAST OF MARQUETTE WILL
CONTINUE TO SEE LIGHT AND MAYBE MODERATE SNOW ACCUMS AND CONTINUING
BLOWING SNOW. HEAVIER SNOW LIKELY OCCURS OVERNIGHT MONDAY NIGHT
THROUGH EARLY TUESDAY MORNING WHEN DIURNAL DISRUPTION IS MINIMAL
AND WHEN LOW-LEVEL CONVERGENCE IS STRONGEST. POSSIBLE THAT MORE
ADVISORIES MAY BE NEEDED MONDAY NIGHT THROUGH TUESDAY MORNING IN
AREAS THAT ARE CURRENTLY IN A HEADLINE.
SFC-H85 FLOW BECOMES INCREASINGLY ANTICYCLONIC TUESDAY WHICH OFFSETS
SUFFICIENT OVER-WATER INSTABILITY AS H85 TEMPS STAY AOB -15C THROUGH
18Z TUESDAY. GFS SOUNDINGS SHOW INVERSION FALLING BLO 5KFT OVR WEST
AFT 12Z AND TO AROUND 5KFT FOR AREAS OVR EASTERN CWA. NO ADDITIONAL
DEEPER MOISTURE AND CYCLONIC FLOW AT A MINIMUM SHOULD COMBINE WITH
HIGHER EARLY APRIL SUN ANGLE/BLYR HEATING TO CONSIDERABLY DISRUPT
LAKE EFFECT BY TUESDAY AFTN. GFS/GEM-NH SLIGHTLY LOWER WITH HEIGHTS
AND COLDER AT H85 FARTHER WEST TUESDAY NIGHT INTO EARLY WEDNESDAY
MORNING. RESULT IS AT LEAST ISOLD LK EFFECT CONTINUING OVER FAR
EASTERN CWA. ECMWF MORE PROGRESSIVE WITH HEIGHTS AND KEEPS COLDER
AIR ON THE MOVE LEADING TO LESS OF CHANCE OF LK EFFECT INTO
WEDNESDAY. SOME HINT OF ANOTHER WEAKER TROUGH UPSTREAM THAT WILL
HAVE TO DROP ACROSS THE UPPER LAKES AS LARGER TROUGH MOVES TO EAST.
WILL HEDGE FORECAST TOWARD GFS/GEM-NH IDEA.
SHORTWAVE RIDGING SLIDES ACROSS AREA FOR WEDNESDAY. LINGERING LK
EFFECT CLOUDS/FLURRIES IN THE MORNING EAST...BUT THIS SHOULD BREAK
UP IN AFTN WITH ARRIVAL OF SFC-H925 RIDGE. MAY SEE INCREASING HIGH
CLOUDS OVER WEST BY LATE AFTN. OTHERWISE...A WARMER DAY SHAPING UP
WITH LIGHT WINDS/LAKE BREEZES. MIXING TO H9-H85 SUPPORTS MAX TEMPS
AS WARM AS LOWER 40S IN THE WEST AND STILL ABOVE THE FREEZING MARK
ELSEWHERE.
HIGH CLOUDS SPILLING IN LATE ON WEDNESDAY ARE IN ADVANCE OF
SHORTWAVE TROUGH TRACKING ACROSS NORTHERN MANITOBA AND NORTHERN
ONTARIO. MODELS STILL AT ODDS HOW QUICKLY THIS SYSTEM MOVES
THROUGH WEDNESDAY NIGHT AND THURSDAY. 00Z GFS WAS SLOWER BUT 06Z
LOOKS MORE LIKE ECMWF. GEM-NH WRAPPED UP AND SLOWER. HEIGHT FALLS
AND H7-H5 Q-VECTOR CONVERGENCE FOCUS MOST PRECIPITATION WELL TO
NORTH OF LK SUPERIOR. SFC-H85 FRONT/1000-850MB MOISTURE CONVERGENCE
SWINGING ACROSS LK SUPERIOR AND UPR MICHIGAN...ALONG WITH RIBBON OF
HIGHER H85-H7 MOISTURE...H85 MOISTURE/TEMPERATURE ADVECTION AND
STEEPER H7-H5 LAPSE RATES AOA 6.5C/KM NOSING IN FROM WEST ADD UP TO
BRIEF PERIOD OF SCATTERED PRECIPITATION AS FRONT WORKS THROUGH. IF
TIMING IS LIKE ECMWF...THEN BETTER CHANCES WILL BE IN THE NORTH. IF
TIMING ENDS UP SLOWER...THEN MORE AREAS SEE CHANCES AS HEATING
OF THE DAY COMBINES WITH THE FORCING. EVEN WITH SLOWER IDEA...MOST
PRECIP SHOULD BE OUT OF AREA BY MID AFTN. PTYPE ALSO DEPENDS ON
TIMING AS A LATER ARRIVAL WOULD BRING RAIN POTENTIAL INTO MIX.
FOR NOW...LOOKS LIKE MOSTLY SNOW AS SOUNDINGS INDICATE WET BULB
FALLS BLO ZERO EXCEPT FOR FAR LOWEST REACHES OF BLYR. ONCE FRONT
MOVES THROUGH QUIET WEATHER EXPECTED THROUGH FRIDAY AS HIGH PRESSURE
DRIFTS ACROSS. GFS A FEW DEGREES COLDER AT H85 ON FRIDAY COMPARED TO
ECMWF AND THUS HAS MORE IN WAY OF LAKE EFFECT CLOUDS.
SYSTEM FOR NEXT WEEKEND STILL SHOWING UP...BUT THERE REMAIN SOME
BIG QUESTIONS. UPPER LAKES REMAINS ON SOUTHERN EDGE OF STRONGER JET
STREAM RIDING ALONG SOUTHERN TIER OF CANADA...WHICH WILL HELP
ENHANCE PRECIPITATION ALONG SFC-H85 BAROCLINIC ZONE. WHERE THAT ZONE
IS LOCATED IS UNCERTAIN. AS MID-LEVEL FLOW BECOMES MORE WESTERLY...
SHORTWAVE TROUGH AND SFC-H85 LOWS MOVE FROM ROCKIES ACROSS THE
NORTHERN PLAINS INTO WESTERN GREAT LAKES. OPERATIONAL MODELS FROM
LAST NIGHT AND NAEFS ENSEMBLES INDICATED SLOWER ARRIVAL TO
PRECIPITATION NOT IMPACTING MUCH OF UPR MICHIGAN UNTIL SATURDAY
NIGHT. OF COURSE THE 12Z MODELS HAVE TRENDED QUICKER AGAIN. ECMWF IS
A LOT QUICKER...BRINGING QPF OVER MOST OF UPR MICHIGAN BY 12Z
SATURDAY...AND BASED ON 1000-500MB THICKNESS/H85 TEMPS IS SHOWING
BETTER SHOT AT MIXED PRECIPITATION. KIND OF SEEMS LIKE ECMWF IS
SHOWING TWO SEPARATE WAVES OF QPF AND THAT IS WHY IT APPEARS MUCH
FASTER WITH QPF ARRIVAL. POOR RUN-TO-RUN CONSISTENCY CONTINUES WITH
THE SYSTEM. UNTIL CONSISTENCY IMPROVES WILL KEEP WITH CONSENSUS OF
MODELS FOR THIS SYSTEM FOR POPS. ENOUGH OF A SIGNAL FROM MODELS OVER
LAST COUPLE DAYS TO GO WITH RAIN AND SNOW FOR PTYPE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 136 PM EDT SUN MAR 31 2013
DAYTIME HEATING AND DEVELOPMENT OF MIXED LAYER SHOULD GENERALLY
RESULT IN VFR CLOUD BASES THIS AFTN AT KIWD/KCMX/KSAW. HOWEVER...
WITH KCMX CLOSER TO SFC LOW TRACKING ACROSS NRN LAKE SUPERIOR AND
ASSOCIATED LOW-LEVEL MOISTURE WRAPPING AROUND IT...CIGS WILL DROP TO
MVFR AT TIMES THERE. EXPECT OCNL -SHSN WHICH WILL REDUCE VIS TO MVFR
AT TIMES...PERHAPS VERY BRIEF IFR. WNW WINDS WILL BE GUSTY THRU THE
AFTN...ESPECIALLY AT THE MORE EXPOSED KCMX WHERE WIND GUSTS UPWARDS
OF 35KT SHOULD BE COMMON. WITH NOCTURNAL COOLING AND THE ARRIVAL OF
SOME DEEPER MOISTURE...EXPECT MVFR CONDITIONS WITH -SHSN TONIGHT AT
ALL 3 SITES AS THE GUSTY NW WINDS CONTINUE TO DRAW COLDER AIR INTO
THE UPPER LAKES. MAY SEE SOME VERY BRIEF PERIODS OF IFR VIS AT KIWD
AND KCMX.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 451 PM EDT SUN MAR 31 2013
STRONG NORTH TO NORTHWEST GALES TO 45 KTS INTO EARLY THIS EVENING
AS COLD FRONT CROSSES LK SUPERIOR. STRONGEST WINDS OCCUR THROUGH
LATE EVENING IN CORRIDOR FROM CNTRL LK SUPERIOR BUOY TO STANNARD
ROCK AND ACROSS REST OF EASTERN LK SUPERIOR. GALES CONTINUE THROUGH
MONDAY AND MONDAY NIGHT OVER SAME AREAS...BUT NOT QUITE AS STRONG.
WINDS DIMINISH TO LESS THAN 25 KTS BY WEDNESDAY MORNING AS BRIEF
RIDGING MOVES ACROSS. STRONGER SOUTHWEST WINDS TO 30 KTS THEN
EXPECTED WEDNESDAY NIGHT AND THURSDAY MORNING AS LOW PRESSURE
CROSSES NORTHERN ONTARIO AND DRAGS COLD FRONT ACROSS LK SUPERIOR.
NORTHWEST WINDS TO 25 KTS DEVELOP BEHIND THE FRONT INTO NEXT
WEEKEND. THE STRONG WINDS WILL DRAW MUCH COLDER AIR INTO THE UPPER
LAKES EARLY THIS WEEK RESULTING IN FREEZING SPRAY THROUGH TUESDAY
NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND ADVISORY UNTIL 9 PM EDT THIS EVENING FOR MIZ001.
WINTER WEATHER ADVISORY UNTIL 2 PM EDT MONDAY FOR MIZ006-007-085.
LAKE SUPERIOR...
GALE WARNING UNTIL 6 AM EDT TUESDAY FOR LSZ250-251-266-267.
GALE WARNING UNTIL 6 PM EDT MONDAY FOR LSZ244-245-264-265.
GALE WARNING UNTIL 5 PM EDT MONDAY FOR LSZ249.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...JLA
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
339 PM EDT SUN MAR 31 2013
.SHORT TERM...THROUGH TONIGHT
DEEPENING LOW PRESSURE SYSTEM OVER THE NORTHERN GREAT LAKES SENT A
WEAK TROUGH/COLD FRONTAL BOUNDARY THROUGH THE AREA THIS MORNING WITH
LITTLE IN THE WAY OF PRECIP ASSOCIATED WITH IT. IMPRESSIVE DRY SLOT
BEHIND THE TROUGH WITHIN A REGION OF DEEP MIXING HAS CLEARED OUT
MOST OF THE CLOUDS ALLOWING TEMPS TO SPIKE INTO THE MID 50S. THE
DEEP MIXING HAS ALSO PRODUCED GUSTS TO AROUND 20 KNOTS THIS
AFTERNOON. A STRONGER TROUGH/FRONT WILL GET SENT THROUGH THE REGION
THIS EVENING. MODELS INDICATE STEEP LOW LEVEL LAPSE RATES AND CAPE
VALUES BETWEEN 50-100 J/KG WITH A NARROW BAND OF THETA E JUST AHEAD
OF THE TROUGH. THEY ALSO SHOW FAIRLY LOW PWATS TIED IN THE LOW
LEVELS BRIEFLY SPIKING WITH THE THETA E AXIS BUT DRYING OUT RAPIDLY
BEHIND THE TROUGH. THE HRRR AND HIRES WRF BOTH SHOW A PERIOD OF
SHOWERS...RAIN BECOMING A MIX OF RAIN AND SNOW...BETWEEN 00Z AND 06Z
WITH POSSIBLE FLURRIES OR LIGHT SNOW SHOWERS AFTER THAT. AN AREA OF
PRECIP IS CURRENTLY SHOWING UP ON REGIONAL RADAR WITHIN THE TROUGH
SO BESIDES FINE TUNING SOME TIMING ISSUES...SEE NO REASONS TO CHANGE
MUCH WITH THE OVERNIGHT POPS/WX. WITH THE POSSIBLE CONVECTIVE NATURE
OF THE PRECIP AND LONGER DURATION...WILL LEAVE A FEW TENTHS OF SNOW
ACCUMULATIONS TO THE NORTH. WINDS WILL STAY ELEVATED OVERNIGHT WHICH
WOULD TYPICALLY LEAD TOWARD WARMER MIN TEMPS BUT CAA BEHIND THE
TROUGH WILL DROP 850MB TEMPS FROM +1C TO -11C OVERNIGHT. DEWPOINTS
UPSTREAM IN THE TEENS WILL TRY TO WORK THEIR WAY INTO THE SAGINAW
VALLEY AS WELL SO WE WILL STILL COOL OFF QUITE A BIT TONIGHT.
&&
.LONG TERM... MONDAY THROUGH NEXT SUNDAY
POLAR AIR NOW INFILTRATING THE UPPER MS VALLEY WILL BE OVER THE
GREAT LAKES REGION BY MONDAY MORNING. THIS AIRMASS IS ASSOCIATED
WITH A POLAR VORTEX NOW LOCATED OVER NRN ONTARIO. THIS UPPER LOW IS
FORECAST TO DEEPEN AS IT TRACKS NORTHEAST OF LAKE HURON AND INTO
QUEBEC ON MONDAY AND WILL REMAIN RATHER PROGRESSIVE...LIFTING INTO
NEWFOUNDLAND BY MIDWEEK. BY 12Z MON...850MB TEMPS ARE STILL FORECAST
TO PLUNGE TO -12 TO -14C OVER SE MI. WEAK MID LEVEL IMPULSES
TRACKING INTO THE REGION TUES/TUES NIGHT WILL HOLD SOME DEGREE OF
MID LEVEL TROUGHING OVER THE GREAT LAKES...WITH SE MI REMAINING
FIRMLY WITHIN THE LOW LEVEL THERMAL TROUGH. DESPITE SOME INTERVALS
OF SUN AND MIXING HEIGHTS EXTENDING UP TO 800MB...THE DEPTH OF COLD
AIR WILL REMAIN SUPPORTIVE OF DAYTIME HIGHS MON AND TUES MAINLY IN
THE 30S. NIGHTTIME MINS ARE EXPECTED TO DROP OFF INTO THE 20S
/POSSIBLY SOME TEENS IF THE BOUNDARY LAYER CAN DECOUPLE/. THESE
TEMPS ARE A GOOD 10 TO 15 DEGREES BELOW SEASONAL AVERAGES. W-NW
WINDS WILL BE QUITE GUSTY ON MONDAY AS DEEPENING SFC LOW PRESSURE
OVER QUEBEC SUSTAINS A TIGHT LOW LEVEL GRADIENT OVER THE REGION.
SOME GUSTINESS TO THE WINDS IS LIKELY TO HOLD THROUGH MUCH OF
TUESDAY AS THE LAKE AGGREGATE MAINTAINS A HEALTHY GRADIENT OVER SRN
LOWER MI. THIS WILL PUT WIND CHILL READINGS IN THE TEENS AND 20S MON
AND TUES.
THE STEEP LOW LEVEL LAPSE RATES COURTESY OF THE COLD AIR WILL ALLOW
A DIURNAL ENHANCEMENT TO THE CLOUDS MON AND TUES AFTERNOON. THE CORE
OF THE MID LEVEL COLD POOL WILL HOWEVER TRACK TO THE NORTHEAST OF
THE FORECAST AREA...THUS KEEPING CONVECTIVE CLOUD DEPTHS RATHER
SHALLOW UNDER A MID LEVEL INVERSION. THIS ALONG WITH SUBSTANTIAL LOW
LEVEL DRY AIR ADVECTION WILL SUPPORT JUST SCATTERED SNOW SHOWERS ON
MONDAY. THE 12Z MODEL SUITE DO SHOW A MID LEVEL IMPULSE /NOW LOCATED
OVER FAR NORTHERN CANADA/ DIVING INTO THE WESTERN GREAT LAKES LATE
TUES. THE CURRENT MODEL SUITE SUGGEST THIS FEATURE WILL ARRIVE INTO
SE MI TOWARD THE END OF THE DIURNAL CYCLE...WHICH SUPPORTS HOLDING
ONTO THE DRY FORECAST AT THIS TIME.
A SPLIT FLOW PATTERN IS FORECAST ACROSS NORTH AMERICA BY MID-LATE
NEXT WEEK...WITH A FAST MOVING NORTHERN STREAM WAVE EXPECTED TO
BRING A COLD FRONT INTO SRN MI IN THE THURS NIGHT/FRIDAY TIME FRAME.
STEADY WARM AIR ADVECTION WILL ALLOW TEMPS TO RISE BACK UP INTO THE
50S ON THURSDAY PRIOR TO THE COLD FRONT PASSAGE. WHILE THE MEDIUM
RANGE MODEL SUITE ARE IN GOOD AGREEMENT IN SHOWING A STRONG LOWER
TROPOSPHERIC BAROCLINIC ZONE SETTING UP ACROSS THE NRN PLAINS AND
GREAT LAKES REGION BY NEXT WEEKEND...THERE IS CONSIDERABLE
DIFFERENCES WITH RESPECT TO THE TIMING AND AMPLITUDE OF MID LEVEL
SHORT WAVE ENERGY EMANATING FROM THE PACIFIC AND TRACKING ALONG THE
BAROCLINIC ZONE. LARGE SPREAD AMONG ENSEMBLE MEMBERS ADDS TO THE
UNCERTAINTY. THERE IS HOWEVER ENOUGH CONFIDENCE TO CARRY A CHANCE OF
PRECIP NEXT WEEKEND.
&&
.MARINE...
DEEPENING LOW PRESSURE SYSTEM OVER THE NORTHERN GREAT LAKES WILL
DROP THE SECOND OF TWO SURFACE TROUGHS THROUGH THE GREAT LAKES THIS
EVENING...USHERING A MUCH COLDER AIRMASS INTO THE REGION. STRONG
WESTERLY WINDS WILL VEER TO THE NORTHWEST BEHIND THIS TROUGH AND
INCREASE WITH A TIGHTENING PRESSURE GRADIENT...ESPECIALLY OVER THE
NORTHERN HALF OF LAKE HURON OVERNIGHT. A GALE WARNING HAS BEEN
ISSUED FOR THE OPEN WATERS OF NORTHERN LAKE HURON WITH SMALL CRAFT
ADVISORIES FOR ALL NEARSHORE WATERS OF LAKE HURON. WINDS WILL REMAIN
ELEVATED THROUGH MONDAY NIGHT.
&&
.AVIATION...ISSUED 137 PM EDT SUN MAR 31 2013
//DISCUSSION...
LINGERING MVFR CIGS WILL LIFT TO VFR AS MIXING INCREASES THIS
AFTERNOON. THE DEEP MIXING WILL ALLOWS WINDS TO GUST UP 25 KNOTS
INTO THIS EVENING. THE SECOND COLD FRONT OF THE DAY WILL
DROP THROUGH SE MI LATE THIS EVENING VEERING WINDS TO NW AND
POSSIBLY PRODUCING SOME LIGHT RAIN SHOWERS THIS EVENING OR A
RAIN/SNOW MIX OVERNIGHT...WHILE DROPPING CIGS BACK TO MVFR. COVERAGE
AND CONFIDENCE OF PRECIPITATION TOO LOW TO INCLUDE IN THE TAFS ATTM.
THE STRONG COLD FRONT WILL ALLOW WINDS TO STAY ELEVATED THROUGH THE
NIGHT.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE THAT CEILINGS WILL FALL BELOW 5000 FEET THIS
EVENING THROUGH MONDAY MORNING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
GALE WARNING...LHZ361-LHZ362-LHZ363-LHZ462...FROM 10 PM SUNDAY TO
10 PM MONDAY.
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS
FROM PORT AUSTIN TO HARBOR BEACH...FROM 10 PM SUNDAY TO 8 AM
TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO PORT
HURON...FROM 4 AM MONDAY TO 8 AM TUESDAY.
SMALL CRAFT ADVISORY...INNER SAGINAW BAY...FROM 4 AM MONDAY TO 10
PM MONDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...DRK
LONG TERM....SC
MARINE.......DRK
AVIATION.....DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
137 PM EDT SUN MAR 31 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 544 AM EDT SUN MAR 31 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A DEEPENING UPR
TROF OVER CENTRAL NAMERICA DOWNSTREAM OF RDG OFF THE W COAST AS
FAIRLY VIGOROUS SHRTWV NEAR LK WINNIPEG IS DIGGING SEWD TOWARD NW
MN. SHRTWV RESPONSIBLE FOR PCPN ON SAT IS NOW OVER LOWER MI...AND
ARRIVAL OF MUCH DRIER AIR SHOWN ON THE 00Z INL RAOB IS TENDING TO
BREAK UP LINGERING FOG/LO CLD AT LEAST OVER THE WRN TIER DESPITE
UPSLOPE LLVL WNW FLOW IN WAKE OF SFC LO PRES TROF ASSOCIATED WITH
THAT DISTURBANCE. SINCE THE INCOMING AIRMASS WITH 00Z H85 TEMP OF
-2C AT INL IS NOT SUFFICIENTLY COLD FOR LES EITHER...THERE IS NO
PCPN. LOOKING UPSTREAM...AN AREA OF MID CLD IS PRESENT OVER NW MN/
NW ONTARIO AHEAD OF THE LK WINNIPEG SHRTWV AND ASSOCIATED COLD FNT
PLUNGING SSEWD. PCPN AHEAD OF THIS BNDRY IS ABSENT GIVEN THE DRYNESS
OF THE INL/YPL RAOBS DESPITE SOME RATHER SHARP DVPA/H85-5 QVECTOR
CNVGC...BUT SOME PLACES SHOW SN IMMEDIATELY BEHIND THE FROPA.
ALTHOUGH H85 TEMPS FALL SHARPLY BEHIND THE COLD FNT TO -14C AT THE
PAS IN MANITOBA NEAR LK WINNIPEG...THE 00Z RAOB FM THAT SITE SHOWS A
FAIRLY DRY AIRMASS/INVERTED V T-TD PROFILE BLO H85. BUT JUST TO THE
E WITHIN THE COLDER AIRMASS...MORE CLDS/-SN ARE EVIDENT IN FAR NW
ONTARIO.
MAIN FCST CONCERNS THRU TNGT ARE SHSN POTENTIAL AND WINDS ASSOCIATED
WITH AND FOLLOWING SHRTWV DIGGING TOWARD THE UPR GRT LKS/ATTENDANT
COLD FROPA.
EASTER SUN...AS LLVL DRY AIR MOVES IN EARLY THIS MRNG...EXPECT TREND
TOWARD FOG/ST TO BREAK UP W-E. BUT ARRIVAL OF COLD FNT OVER THE NW
BY LATE MRNG WL RESULT IN MORE CLDS AND SHSN IN THIS AREA AS AREA OF
MSTR IN NW MN/ADJOINING ONTARIO SWINGS OVHD. SINCE THE MOST
IMPRESSIVE DPVA/H85-5 QVECTOR CNVGC IS PROGGED TO SWING BY TO THE N
OF UPR MI...EXPECT ACCOMPANYING SHSN TO BE RELATIVELY MODEST EVEN IF
THERE IS SOME ENHANCEMENT OVER MAINLY THE HIER TERRAIN OF THE NW. AS
THE FNT SWINGS THRU THE REST OF THE CWA EARLY THIS AFTN...DEEP LYR
QVECTOR DVGC/MID LVL DRYING SHOULD LIMIT PCPN TO SCT -SHSN THAT WL
BE AT LEAST MIXED WITH RA OVER THE SCNTRL AS TEMPS RISE AOA 40 IN
THOSE DOWNSLOPE AREAS. BEST CHC FOR MORE NMRS SHSN WL BE OVER THE
NRN TIER CLOSER TO SHRTWV DYNAMICS. EVEN WITH STRENGTHENING NW
FLOW/CAD BEHIND THE FROPA THAT DROPS H85 TEMPS TO NEAR -14C BY 00Z
MON...ARRIVAL OF DRIER AIR MORE REPRESENTED BY THE 00Z YQD RAOB
ALONG WITH DAYTIME HEATING/INVERTED V LOOK TO GFS FCST SDNGS FOR CMX
SHOULD TEND TO LIMIT THE SHSN INTENSITY IN THE WAKE OF THE FROPA. AS
FOR THE WINDS...THE PREFERRED GFS SHOWS A FAIRLY SHARP PRES RISE
CENTER FOLLOWING THE FROPA AND REACHING NCENTRL LK SUP BY 00Z WITH
ISALLOBARIC WIND FAVORABLY ALIGNED WITH THE NW GRADIENT FLOW. SINCE
SEVERAL MODELS SHOW H925 WINDS UP TO 40 KTS STREAMING INTO THE ERN
ZNS AT 00Z WITH CONSIDERABLE CAD/DESTABILIZATION AS WELL AS THE
FAVORABLE ALIGNMENT OF THE ISALLOBARIC WIND TO THE GRADIENT FLOW...
EXPECT ADVY LVL GUSTS TO 45 MPH IN THE EXPOSED LK SUP SHORELINE E OF
MQT AFT 21Z.
AS THE CLOSED LO OVER SE CANADA MOVES TO THE E TNGT...SHARP CYC NW
FLOW IS PROGGED TO VEER A BIT MORE TOWARD THE NNW...WHICH MIGHT
ALLOW DEEPER MSTR NOW OVER NW ONTARIO TO INFILTRATE THE UPR LKS AS
SHOWN BY NMRS MODEL H7 RH PROGS. IN COMBINATION WITH H85 TEMPS
FALLING AS LO AS -17C TO -18C AND NOCTURNAL COOLING THAT WOULD FAVOR
MORE TYPICAL LES BANDING...MAINTAINED THE FLAVOR OF PREVIOUS FCST
WITH LES POPS INCRSG TO CATEGORICAL IN THE SN BELTS FAVORED BY THE
EXPECTED FLOW. NEARLY UNIDIRECTIONAL NATURE OF THE SFC-H85 FLOW IN
THE WELL MIXED CONVECTIVE LYR MIGHT ALSO FAVOR HEAVIER SN BANDS.
SINCE THE ERN ZNS WL BE CLOSER TO THE DEPARTING LO...HAVE A BETTER
OPPORTUNITY TO BE IMPACTED BY THE DEEPER MSTR...AND WL SEE ADVY LVL
WIND GUSTS AT LEAST THRU 06Z BEFORE THE PRES RISE CENTER SHIFTS
FARTHER E AND WEAKENS THE ISALLOBARIC WIND...OPTED TO ISSUE A WINTER
WX ADVY FOR ALGER/NRN SCHOOLCRAFT/LUCE COUNTIES FOR THE COMBINATION
OF STRONG WINDS...LES...AND BLSN.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 544 AM EDT SUN MAR 31 2013
AFTER A SEVERAL DAY STRETCH OF NEAR NORMAL EARLY SPRING WEATHER...IT
LOOKS LIKE A RETURN TO FEBRUARY LIKE WEATHER IS ON TAP FOR THE EARLY
PART OF THE WORK WEEK. COLD ADVECTION WILL CONTINUE ON MONDAY ON THE
BACKSIDE OF UPPER TROUGH PUSHING THROUGH THE UPPER LAKES. 85H TEMPS
FALL DOWN TO AROUND -18C ACROSS LAKE SUPERIOR DURING THE DAY ON
MONDAY. UNUSUAL TO BE DEALING WITH LAKE EFFECT IN EARLY APRIL BUT
WITH LAKE TEMPS BETWEEN 1-2C...SUFFICIENT DELTA TS WILL BE IN PLACE
FOR LAKE EFFECT SNOW IN NORTHWESTERLY WIND SNOW BELTS. THE CHALLENGE
OF THE FCST IS THE EXTENT OF ACCUMULATIONS AND OVERALL IMPACTS OF
THE SNOW. THE FACT THAT IT IS APRIL...FCST SOUNDINGS ARE SHOWING A
LOW LEVEL INVERTED V SIGNATURE...THE TYPICAL DISRUPTION IN THE LAKE
EFFECT PROCESS FROM DIURNAL HEATING THIS TIME OF YEAR...ALL LEND TO
THE UNCERTAINTY IN THE FCST. AREAS MOSTLY LIKELY TO SEE MORE OF THE
IMPACTS WILL BE ALGER AND LUCE COUNTIES AND WILL LET WINTER WEATHER
ADVISORY EXTEND THROUGH MONDAY MORNING TO ACCOUNT FOR FALLING SNOW
AND BLOWING SNOW...ESPECIALLY NEAR LAKE SUPERIOR. THE NEGATIVES
LISTED ABOVE MAY THEN BECOME TOO MUCH FOR SIGNIFICANT IMPACTS DURING
THE AFTERNOON MONDAY. AWAY FROM THIS AREA...EXPECT LAKE EFFECT SNOW
SNOW SHOWERS TO PRODUCE SOME LIGHT ACCUMULATIONS ACROSS THE KEWEENAW
AND WESTERN U.P. THE MOST NOTICEABLE THING ABOUT MONDAY WILL BE THE
FACT THAT TEMPERATURES WILL ONLY CLIMB INTO THE LOWER TO MID 20S AND
WITH GUSTY NORTHWEST WINDS IT WILL FEEL CONSIDERABLY COLDER.
THERE COULD BE A SLIGHT UPTICK IN LAKE EFFECT SNOW MONDAY NIGHT
ACROSS THE EAST WITH INVERSION HEIGHTS REMAINING AROUND
8KFT...TRAJECTORIES FAVORING A LITTLE MORE LOW LEVEL MOISTURE...AND
TYPICAL NIGHTTIME INCREASE IN LAKE EFFECT THIS TIME OF YEAR. MAY NEED
TO CONSIDER ANOTHER ADVISORY FOR ALGER AND LUCE COUNTIES AGAIN
MONDAY NIGHT. ELSEWHERE...EXPECT LAKE EFFECT SNOW SHOWERS TO
CONTINUE ACROSS THE WEST BUT ACCUMULATIONS SHOULD REMAIN RELATIVELY
LIGHT.
LAKE EFFECT PROCESS WINDS DOWN QUICKLY ON TUESDAY WITH INVERSION
LOWERING SIGNIFICANTLY AND SURFACE RIDGING APPROACHING FROM THE
WEST. TEMPERATURES WILL REMAIN WELL BELOW NORMAL...MORE LIKE MID
FEBRUARY.
RIDGE AXIS WILL MOVE ACROSS THE AREAM ON WEDNESDAY. WITH ABUNDANT
SUNSHINE AND WARM ADVECTION COMMENCING ON THE BACK SIDE OF THE RIDGE
TEMPS SHOULD REBOUND BACK ABOVE FREEZING TO WITHIN A FEW DEGREES OF
NORMAL. NEXT TROUGH AND FRONT WILL CROSS THE AREA ON THURSDAY. NOT
VERY MUCH MOISTURE TO WORK WITH SO ONLY EXPECT SOME LIGHT RAIN AND
SNOW SHOWERS WITH ITS PASSAGE. ANOTHER DECENT COLD SHOT WILL KNOCK
TEMPERATURES BACK BELOW NORMAL FOR FRIDAY. HAVENT LOOKED TOO MUCH AT
NEXT WEEKENDS FORECAST BUT THERE APPEARS TO BE A TREND POINTING
TOWARD A MORE SOUTHERN TRACK OF A STORM SYSTEM PUSHING THROUGH THE
LOWER LAKES. WILL BE SOMETHING TO KEEP AN EYE ON AS THE WEEK
PROGRESSES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 136 PM EDT SUN MAR 31 2013
DAYTIME HEATING AND DEVELOPMENT OF MIXED LAYER SHOULD GENERALLY
RESULT IN VFR CLOUD BASES THIS AFTN AT KIWD/KCMX/KSAW. HOWEVER...
WITH KCMX CLOSER TO SFC LOW TRACKING ACROSS NRN LAKE SUPERIOR AND
ASSOCIATED LOW-LEVEL MOISTURE WRAPPING AROUND IT...CIGS WILL DROP TO
MVFR AT TIMES THERE. EXPECT OCNL -SHSN WHICH WILL REDUCE VIS TO MVFR
AT TIMES...PERHAPS VERY BRIEF IFR. WNW WINDS WILL BE GUSTY THRU THE
AFTN...ESPECIALLY AT THE MORE EXPOSED KCMX WHERE WIND GUSTS UPWARDS
OF 35KT SHOULD BE COMMON. WITH NOCTURNAL COOLING AND THE ARRIVAL OF
SOME DEEPER MOISTURE...EXPECT MVFR CONDITIONS WITH -SHSN TONIGHT AT
ALL 3 SITES AS THE GUSTY NW WINDS CONTINUE TO DRAW COLDER AIR INTO
THE UPPER LAKES. MAY SEE SOME VERY BRIEF PERIODS OF IFR VIS AT KIWD
AND KCMX.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 544 AM EDT SUN MAR 31 2013
AS A STRONG DISTURBANCE MOVES OVER LK SUP TODAY...A DEEP LO PRES
WILL TAKE SHAPE OVER SE CANADA AND CAUSE NW WIND TO INCREASE TO GALE
FORCE OVER THE NCENTRAL AND E PORTIONS OF THE LAKE BY THIS
AFTERNOON. THESE STRONG NW WINDS WILL CONTINUE TONIGHT AND DRAW MUCH
COLDER AIR INTO THE UPPER LAKES. THE RESULT WILL BE FREEZING SPRAY.
MAINTAINED GOING GALE WARNING FOR MOST OF THE NCENTRAL AND E HALF.
NORTHWEST GALES WILL CONTINUE ACROSS THE EASTERN HALF OF LAKE
SUPERIOR INTO TUESDAY BEFORE RIDGING BUILDS ACROSS THE LAKE WITH
WINDS DIMINISHING TO LESS THAN 20 KNOTS. WINDS SHOULD REMAIN BELOW
20 KNOTS INTO THURSDAY BEFORE THE NEXT QUICK MOVING FRONT MOVES
ACROSS THE UPPER GREAT LAKES. NORTHWEST WINDS TO 30 KNOTS WILL BE
POSSIBLE BEHIND THE FRONT TO END THE WORK WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 2 PM EDT
MONDAY FOR MIZ006-007-085.
LAKE SUPERIOR...
GALE WARNING UNTIL 8 PM EDT TUESDAY FOR LSZ264>267.
GALE WARNING UNTIL 6 PM EDT MONDAY FOR LSZ244-245-249>251.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...MZ
AVIATION...ROLFSON
MARINE...KC/MZ
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
127 PM EDT SUN MAR 31 2013
.SYNOPSIS...
ISSUED AT 330 AM EDT SUN MAR 31 2013
TEMPERATURES WILL AVERAGE NEAR NORMAL TODAY BEFORE ANOTHER ROUND OF
UNSEASONABLY COLD AIR MOVES IN TONIGHT THROUGH TUESDAY. TEMPERATURES
WILL AVERAGE TEN TO FIFTEEN DEGREES BELOW NORMAL MONDAY THROUGH
TUESDAY WITH A FEW LIGHT LAKE EFFECT SNOW SHOWERS AND FLURRIES FROM
THE EARLY MORNING HOURS MONDAY THROUGH TUESDAY MORNING. TEMPERATURES
WILL MODERATE MID TO LATE WEEK AND RETURN TO NEAR NORMAL BY THURSDAY
AND FRIDAY. DRY WEATHER IS ANTICIPATED MID TO LATE WEEK AS HIGH
PRESSURE BUILDS IN.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY AFTERNOON)
ISSUED AT 1000 AM EDT SUN MAR 31 2013
LOOKING AT A FAIR AMOUNT OF EARLY AFTERNOON SUNSHINE AS LOW LEVEL
MOISTURE MIXES OUT THIS MORNING. STILL LOOKING AT EARLY AFTERNOON
TEMPS RANDING FROM THE UPPER 40S AT THE COAST TO MID 50S INLAND.
ALSO LIKE HI RES GUIDANCE SUGGESTING A COUPLE BANDS OF LIGHT SHRA /
SPRINKLES SPREADING WEST TO EAST AFTER 5PM. SHRA ACTIVITY WILL BE
ALONG AND AHEAD OF LEADING EDGE OF ARCTIC AIR.
EXPECT WESTERLY WIND GUSTS TO 30 MPH INLAND THIS AFTERNOON WITH
INITAL CAA AND MIXING. INITIALLY...STABLE TEMPERATURE STRATIFICATION
OVER THE LAKE WILL INHIBIT GUSTINESS. A SECOND ROUND OF WIND GUSTS
TO 35 MPH WILL AFFECT ALL AREAS AS THE ARCTIC AIR MOVES IN EARLY
THIS EVENING.
SCATTERED WNW FLOW LIGHT LAKE EFFECT SNOW SHOWERS AND FLURRIES WILL
DEVELOP VERY LATE TONIGHT AND CONTINUE MONDAY AS H8 TEMPS FALL TO
-13 TO -15 C BY 12Z MON. HOWEVER WITH A VERY DRY AIRMASS ADVECTING
IN AND LACK OF BETTER MOISTURE OR UPSTREAM RH THIS WILL NOT AMOUNT
TO ANYTHING (TRACE AMOUNTS TO JUST A FEW TENTHS OF AN INCH OF SNOW
FROM THE EARLY MORNING HOURS MONDAY THROUGH EARLY TUESDAY).
ANY LINGERING FLURRIES EARLY TUESDAY SHOULD END WITH AN EVEN DRIER
AIRMASS IN PLACE LATER ON TUESDAY AND AS H8 TEMPS BEGIN TO MODERATE
A BIT BY TUESDAY AFTN.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 AM EDT SUN MAR 31 2013
AFTER THE EARLY WEEK COLD BLAST... IT LOOKS LIKE WINTER WILL LOOSEN
ITS GRIP ON THE GREAT LAKES REGION. MEDIUM RANGE GUIDANCE IS
STARTING TO SHOW SOME CONSISTENCY THAT THE TROUGHING WHICH HAS
PERSISTED MOST OF MARCH OVER THE ERN U.S. WILL FINALLY LIFT OUT.
FOR THE MID TO LATE WEEK PERIOD THE UPPER FLOW WILL BE ZONAL WHICH
IMPLIES UNEVENTFUL WEATHER WITH TEMPERATURES MODERATING TO CLOSER TO
NORMAL VALUES. HOWEVER THERE ARE SIGNS THAT AN UPPER RIDGE WILL
BEGIN TO BUILD OVER THE REGION ABOUT A WEEK FROM NOW AS A DEEP
LONGWAVE TROUGH EVOLVES OVER THE WRN UNITED STATES. THIS IMPLIES
THAT ABOVE NORMAL TEMPERATURES WILL DEVELOP BEYOND DAY 7.
SFC HIGH PRESSURE WEDNESDAY AND THURSDAY OUGHT TO LEAD TO ABUNDANT
SUNSHINE ALTHOUGH RATHER CHILLY NIGHTTIME TEMPERATURES. A WEAK SFC
BOUNDARY DOES DROP SOUTH THROUGH THE REGION ON THURSDAY NIGHT BUT NO
PRECIP IS EXPECTED AS THERE IS LITTLE MOISTURE TO WORK WITH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 126 PM EDT SUN MAR 31 2013
THE BACK EDGE OF THE STRATOCU SHOULD MOVE ONSHORE NEAR KMKG BY 19Z
OR SO AND THEN MOVE EAST TO KGRR BY 20Z OR SHORTLY THERE AFTER.
THINKING THAT KLAN WILL BE SCT AT 18Z AND REMAIN THAT WAY.
HOWEVER...IT/S POSSIBLE THAT KLAN COULD DEVELOP A BKN MVFR CIG FOR
A COUPLE OF HOURS IN THE 19-21Z TIME FRAME IF THE CLOUDS NEAR KGRR
CAN MOVE EAST. VIS LOOP SHOWS THOSE CLOUDS DECAYING ON THE ERN
EDGE AND SO WE LEFT THE CLOUDS SCTD AT KLAN THIS AFTERNOON.
WINDS WILL INCREASE FROM THE NW THIS EVENING AS A COLD FRONT MOVES
THROUGH. SHSN MAY DEVELOP OVERNIGHT ALONG WITH MVFR CIGS.
&&
.MARINE...
ISSUED AT 1000 AM EDT SUN MAR 31 2013
BASED ON LATEST 3KM HRRR GUIDANCE...SMALL CRAFT CONDITIONS WILL
DEVELOP AROUND 00Z (8PM EDT) THIS EVENING...A BIT EARLIER THAN FIRST
EXPECTED. WIND GUSTS AROUND 30 KTS WITH SEAS BUILDING 5 TO 7 FEET
STILL LOOKING GOOD. VISIBILITY WILL OCCASIONALLY DROP BELOW 1 MILE
IN LAKE EFFECT SNOW SHOWERS OVERNIGHT THROUGH MONDAY. HIGH PRESSURE
WILL BRING FAIR WEATHER AND LIGHT WINDS FOR LATE TUESDAY THROUGH
THURSDAY.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT SUN MAR 31 2013
NO HYDRO ISSUES EXPECTED. RIVERS ARE ALL WELL BELOW ACTION STAGE AND
WILL REMAIN SO THROUGH THE WEEK. THE OVERALL WEATHER PATTERN THIS
WEEK WILL BE CONDUCIVE TO A GRADUAL MELTING AND RUNOFF OF REMAINING
SNOW COVER.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 PM EDT TUESDAY
FOR LMZ844>849.
&&
$$
SYNOPSIS...LAURENS
SHORT TERM...COBB
LONG TERM...MEADE
AVIATION...93
HYDROLOGY...LAURENS
MARINE...COBB
AREA FORECAST DISCUSSION
NWS JACKSON MS
359 PM CDT SUN MAR 31 2013
.DISCUSSION...
TODAY THROUGH EARLY WEDNESDAY
WEAKENING SQUALL LINE PUSHING THROUGH THE REGION TO THE SOUTHEAST
TONIGHT WITH QUIETER WEATHER MONDAY AND TUESDAY BEFORE MORE RAIN FOR
MIDDLE TO LATE WEEK.
SEVERAL REPORTS OF TREES AND POWERLINES DOWN HAVE COME IN FROM
NORTHEAST LA AND WEST MS AS THE ONCE STRONGER SQUALL LINE MOVED
THROUGH. HOWEVER, AN OVERALL WEAKENING TREND OVER THE PAST HOUR AS
BEEN OBSERVED AS IT ENCOUNTERS A LESS FAVORABLE AIRMASS TO THE EAST.
WARMING CLOUD TOPS VIA IR SAT AND WEAKENING REFLECTIVITY GRADIENT
FURTHER SUGGEST MCS IS BECOMING COLD POOL DOMINATED WHILE BEING
FARTHER REMOVED FROM LARGER SCALE FORCING. HAVE CANCELED PORTIONS OF
THE SEVERE TSTORM WATCH TO THE WEST OF THE CURRENT LINE. THE BEST
ENVIRONMENT FOR MARGINAL STRONG TO BRIEFLY SEVERE STORMS IS ACROSS
FAR S/SE AREAS WHERE RAP OUTPUT SUGGEST 500-1000 J/KG SBCAPE AND ~30
KT ORGANIZATIONAL DEEP LAYER SHEAR. HOWEVER, FEEL THE COLD POOL
DOMINATION AND LACK OF FORCING SHOULD KEEP MOST STORMS IN CHECK FROM
BEING SEVERE ACROSS THE REMAINDER OF THE AREA. BUT ONE OR TWO STORMS
COULD BRIEFLY BECOME SEVERE ACROSS THIS AREA TROUGH EARLY EVENING.
AS THE TSTORM LINE AND CLOUDS CLEAR TONIGHT FROM THE NORTH,
DEVELOPMENT OF FOG WILL BE LIKELY ACROSS A MAJORITY OF THE REGION.
SOME ISOLATED LOCATIONS OF DENSE FOG ARE PSBL TONIGHT THROUGH 8AM
TOMORROW MRNG. FOG WILL DISSIPATE THROUGH 9AM AS MIXING STEADILY
INCREASES.
THE WEAKENING TSTORM LINE WAS INITIATED ON A LOW-LVL FRONTAL
BOUNDARY AND A NRN STREAM H5 S/WV TROUGH PIVOTING ACROSS THE LOWER
PLAINS. THIS FRONTAL BOUNDARY WILL STALL ALONG THE I-10 TO HIGHWAY
84 CORRIDOR SECTOR OVERNIGHT AND MONDAY. ANOTHER QUICK MOVING
IMPULSE IN THE NW FLOW MAY HELP SOME SHOWERS LINGER THROUGH THE
EARLY MRNG HOURS ACROSS FAR SOUTHERN LOCATIONS. THIS BOUNDARY WILL
SERVE AS A IMPETUS FOR A FEW SHOWERS AND THUNDERSTORMS MON AFTN ALSO
AS DIURNALLY DRIVEN INSTABILITY BUILDS INVOF GREATEST SFC
CONVERGENCE. MAV POPS CAME IN QUITE LOW DESPITE GFS HOLDING UP THE
FRONT ACROSS THIS REGION. THE EC AND NAM ARE IN AGREEMENT OF
DIURNALLY DRIVEN QPF ALSO. THEREFORE, BUMPED POPS UP ACROSS SRN TIER
OVER MAV. FOR CNTRL AND NORTH AREAS HOWEVER, BUFR SOUNDINGS SUGGEST
AMPLE SUN WITH TEMPS RISING INTO THE MID 70S AS SFC HIGH PRESSURE
AXIS NOSES IN.
THE SFC HIGH PRESSURE WILL ALSO AID IN A REINFORCING SHOT OF
COOLER/DRIER AIR IN THE LOW LEVELS TUESDAY MRNG THAT WILL QUELL
TEMPS FROM REACHING MONDAY`S LEVELS. MID AND HIGH LEVEL CLOUDS WILL
BE ON THE INCREASE TUESDAY INTO TUESDAY NIGHT AS OUR NEXT SYSTEM
TAKES SHAPE ACROSS THE INTER-MOUNTAIN WEST. A SUPPRESSED PACIFIC H5
S/WV TROUGH WILL SWING ACROSS THE FOUR CORNERS REGION LATE TUESDAY
AND HELP SFC LOW CYCLOGENESIS ACROSS TEXAS. A DECENT PRESSURE
GRADIENT APPEARS TO BE IN PLACE GOING INTO TUES NIGHT WITH SFC HIGH
JUST OFF TO NORTH AND THE DEVELOPING SFC LOW. SMALL PERTURBATIONS/
IMPULSES IN THE H5 FLOW WILL MOVE OVER TOP THE ARKLAMISS LATE TUES
INTO EARLY WEDS AIDING IN ISENTROPIC ASCENT. LIGHT SHOWER ACTIVITY
WILL BE ON THE INCREASE LATE TUES NIGHT INTO WED MRNG FOR WESTERN
AND CENTRAL ARKLAMISS AREAS.
FOR FORECAST ELEMENTS...WINDS WERE BUMPED UP IN ASSOCIATION WITH THE
TSTORM COMPLEX. MAV POPS WERE BUMPED DOWN DRAMATICALLY TONIGHT THEN
SLIGHTLY UP FOR SOUTHERN AREAS DAY PERIOD MONDAY. FOG WAS ADDED TO
THE OVRNGT PERIOD ALSO. MAV POPS WERE GENERALLY FOLLOWED TUESDAY
NIGHT INTO WEDNESDAY. MAV TEMPS WERE DROPPED A TOUCH FOR NRN AREAS
TOMORROW GIVEN BUFR SOUNDINGS AND MAX HEATING POTENTIAL. /ALLEN/
&&
.AVIATION...A LINE OF SHOWERS AND THUNDERSTORMS EXTENDS ACROSS THE
CENTRAL PORTIONS OF THE AREA THIS AFTERNOON AND IS CURRENTLY BRINGING
MVFR CONDITIONS TO GWO/HKS/JAN. THIS LINE OF STORMS WILL CONTINUE TO
MOVE EAST AND AFFECT MEI/HBG AND GTR LATER THIS AFTERNOON INTO THE
EARLY EVENING. VFR CONDITIONS ARE RETURNING TO GLH AS DRIER AIR
MOVES OVER THE NORTHWESTERN PORTIONS OF THE AREA. THE SHOWERS AND
THUNDERSTORM WILL MOVE TO THE EAST OF THE AREA EARLY THIS
EVENING...BUT WILL STILL BE POSSIBLE AT HBG THROUGH MUCH OF THE
NIGHT. IFR CONDITIONS ARE ONCE AGAIN POSSIBLE EARLY MONDAY OVER MOST
SITES DUE TO STRATUS AND FOG. /15/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 54 78 49 69 / 27 14 4 20
MERIDIAN 53 77 45 72 / 32 13 4 12
VICKSBURG 54 78 51 68 / 25 14 3 31
HATTIESBURG 60 79 51 74 / 66 22 5 13
NATCHEZ 54 77 54 70 / 59 20 3 28
GREENVILLE 52 75 46 61 / 11 10 3 36
GREENWOOD 51 75 46 65 / 12 10 4 26
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
ALLEN/15
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
104 PM CDT SUN MAR 31 2013
.SHORT TERM...(EASTER SUNDAY)
ISSUED AT 224 AM CDT SUN MAR 31 2013
FORECAST HAS CHANGED TODAY GIVEN CURRENT CONDITIONS AND LATEST SHORT
RANGE MODEL GUIDANCE. SHORTWAVE ENERGY...EVIDENT ON LATEST WATER
VAPOR IMAGERY...DROPPING SOUTHEAST FROM SOUTHERN NEBRASKA HAS LED TO
A LARGE AREA OF SHOWERS AND SOME THUNDERSTORMS DEVELOPING ACROSS
EASTERN KANSAS AND WEST CENTRAL MISSOURI.
LATEST RUC AND HRRR SHOW THIS AREA OF RAIN SHOWERS/STORMS EXPANDING
AS EAST/SOUTHEAST THIS MORNING ACROSS CENTRAL MISSOURI AND THE
OZARKS...PERHAPS GRAZING EAST CENTRAL MISSOURI AND SOUTHWEST
ILLINOIS. WILL FINE TUNE POPS BEFORE FORECAST ISSUANCE BASED ON THE
VERY LATEST RADAR TRENDS.
THERE WILL OBVIOUSLY BE A SLOWER CLEARING TREND TO THE CLOUDS THANKS
TO THIS SHORTWAVE...AND FEEL IT PRUDENT TO SIDE WITH SLIGHTLY COOLER
MAV GUIDANCE FOR HIGH TEMPERATURES.
TO COMPLICATE THE FORECAST EVEN FURTHER...MUCH OF THE EXPLICIT AND
HIGH RESOLUTION MODEL GUIDANCE DEPICT SOME ISOLATED SHOWERS
DEVELOPING ALONG A PREFRONTAL TROF THIS AFTERNOON AND EVENING FROM
CENTRAL ILLINOIS TOWARD THE ST. LOUIS METRO AREA. SO HAVE INCLUDED
SOME LOW CHANCE/ISOLATED POPS FOR THIS AS WELL.
CVKING
&&
.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 224 AM CDT SUN MAR 31 2013
(TONIGHT AND MONDAY)
ARCTIC COLD FRONT EXPECTED TO MOVE SOUTH ACROSS THE CWA TONIGHT
WITH NORTH WIND AND COLD ADVECTION TAKING CONTROL OF THE WEATHER
FOR THE EARLY PART OF THE WORK WEEK. LATEST GUIDANCE CONTINUES TO
DEPICT A BAND OF LIGHT POST FRONTAL PRECIPITATION AFFECTING MAINLY
NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS SUNDAY NIGHT. THIS
PRECIPITATION SHOULD WEAKEN AS IT PROGRESSES SOUTH MONDAY MORNING
TO THE I-70 CORRIDOR. MAINTAINED RAIN/SNOW MIX...BUT DONT EXPECT
ANY ACCUMULATION DUE TO WARM AIR AND GROUND TEMPERATURES. HAVE
SIDED WITH COOLER MET GUIDANCE FOR TEMPERATURES.
(TUESDAY THROUGH SATURDAY)
SLOW WARMING TREND EXPECTED WITH HIGH PRESSURE MOVING EAST OF THE
AREA BY LATE IN THE WEEK. HAVE KEPT FORECAST DRY AS GUIDANCE KEEPS
CUTOFF LOW TO THE SOUTH OF THE AREA THURSDAY.
CVKING
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1242 PM CDT SUN MAR 31 2013
SCATTERED DIURNAL CUMULUS CLOUDS CAN BE EXEPCTED THIS AFTN.
W-NWLY SFC WINDS WILL STRENGTHEN AND BECOME GUSTY THIS AFTN. THESE
NWLY SFC WINDS WILL BECOME NLY TGT AFTER PASSAGE OF A COLD FRONT.
A BAND OF POST FRONTAL LOW-MID LEVEL CLOUDS WILL ADVECT SWD
THROUGH THE TAF SITES LATE TGT AND EARLY MON MRNG. THERE SHOULD BE
A BRIEF PERIOD OF LIGHT SNOW IN UIN LATE TGT INTO EARLY MON MRNG
AS MUCH COLDER AIR FILTERS INTO THE REGION BEHIND THE COLD FRONT.
WILL KEEP ANY PRECIPITATION OUT OF THE REST OF THE TAF SITES
FURTHER S AS IT LOOKS LIKE THIS WILL BE MAINLY JUST SPRINKLES OR
FLURRIES. WILL ALSO KEEP THE CLOUD CEILING VFR AT COU AND THE ST
LOUIS METRO AREA TAFS...ALTHOUGH THERE COULD BE A BRIEF PERIOD OF
MVFR CIGS AROUND 09-15Z MON. MOST OF THIS CLOUD COVER SHOULD
ADVECT S OF THE TAF SITES BY LATE MON MRNG AS A STRONG SFC RIDGE
BUILDS SEWD INTO THE REGION.
SPECIFICS FOR KSTL...JUST SCT CUMULUS CLOUDS THIS AFTN...THEN A
BAND OF MAINLY VFR LOW-MID LEVEL CLOUDS WILL PASS SWD THROUGH STL
BETWEEN 09-15Z MON. THERE COULD BE SPRINKLES OR FLURRIES FROM
THESE CLOUDS BUT WILL KEEP THE STL TAF DRY FOR NOW. JUST SCT LOW
LEVEL CLOUDS LINGERING INTO MON AFTN. NWLY SFC WIND SHOULD
INCREASE SOME AND BECOME GUSTY LATER THIS AFTN...THEN WEAKEN THIS
EVNG. THE NWLY SFC WIND WILLL BECOME NLY BY LATE TGT AFTER FROPA.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
525 PM EDT SUN MAR 31 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION FROM THE WEST TONIGHT...WITH A
SECOND COLD FRONT MOVING OVER THE AREA MONDAY NIGHT. HIGH PRESSURE
WILL FILL IN BEHIND THE SECOND FRONT USHERING IN COOLER THAN NORMAL
TEMPERATURES THROUGH THURSDAY. ON FRIDAY A LOW DEVELOPS IN THE GULF
AND MOVES TOWARDS THE SOUTH CAROLINA COAST.
&&
.NEAR TERM /THROUGH MONDAY/...
AS OF 515 PM EDT...THE LATEST HRRR MESOSCALE MODEL RUNS HAVE BEEN
PERFORMING QUITE WELL IN DEPICTING THE HIGHER/STRONGER CONVECTIVE
COVERAGE ACROSS THE NW PIEDMONT AHEAD OF A DRIVING UPPER SHORTWAVE.
FREEZING LEVELS/WET BULB HEIGHTS IN THOSE AREAS SUPPORT MARGINAL
SEVERE HAIL WITH 55 DBZ CORE HEIGHTS TO 19 TO 20 KFT. THE BETTER
PRE/FRONTAL TSRA SHOULD MOVE EAST THROUGH 00Z THIS EVENING...BUT
WITH SHRA AND ISOLD TSRA COVERAGE LINGERING THROUGH THE EVENING
HOURS. POPS HAVE BEEN REORIENTED TO ACCOUNT FOR THIS.
OTHERWISE...A COLD FRONT WILL APPROACH FROM THE NW AND THEN MOVE
SLOWLY ACROS THE REGION OVERNIGHT THROUGH DAYBREAK MONDAY. THE
POTENTIAL EXISTS FOR PATCHY FOG IN AREAS WHERE WINDS SUBSIDE BEFORE
THE DRYING FRONT MOVES THROUGH. MINIMUM TEMPERATURES WILL BE AROUND
FIVE DEGREES ABOVE NORMAL UNDER CLOUD COVER. THE COLD FRONT IS
EXPECTED TO MOVE EAST THROUGH MONDAY...WITH CLEARING SKIES AND NW
WINDS. HIGH TEMPERATURES WILL BE AROUND FIVE DEGREES ABOVE NORMAL IN
DOWNSLOPE WARMING.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 255 PM SUNDAY...MEAN TROF REMAINS OVER THE ERN US THRU THE
SHORT RANGE. THIS ALLOWS A SERIES OF WEAK SHORT WAVES TO MOVE THRU
THE FLOW AND ACROSS THE AREA EACH DAY. AT THE SFC...A COLD FRONT
DROPS SOUTH ACROSS THE CWFA AND STALLS OVER THE SRN CWFA OR JUST
SOUTH OF THE AREA. WITH THE FRONT STALLED NEAR THE AREA...WAVES TRY
TO DEVELOP ALONG THE FRONT IN RESPONSE TO THE SHORT WAVES MOVING
THRU. THE GUIDANCE AGREES ON CLOUDS DEVELOPING AND MOVING ACROSS THE
AREA. HOWEVER...THE NAM DEVELOPS QUITE A BIT OF ISENTROPIC LIFT
ALONG THE FRONT AS AN H85 LOW DEVELOPS AND PRODUCES SLY FLOW. THE
GFS DOES SOMETHING SIMILAR...BUT WEAKER AND EAST OF OUR CWFA. THE
SREF HAS CLOUDS SIMILAR TO THE GFS AND PRECIP SIMILAR TO BUT LESS
MAGNITUDE THAN THE NAM. GIVEN THE UNCERTAINTY...WILL KEEP THE FCST
DRY THRU THE PERIOD...BUT SHOW INCREASING CLOUDS EARLY...THEN SLOWLY
SHIFT THEM SOUTH. WITH THE INCREASE IN CLOUDS...LOW TEMPS LOOK TO BE
WARMER THAN EARLIER EXPECTED WHICH ARE SLIGHTLY BELOW NORMAL. HIGHS
SHOULD BE 5 TO 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 305 PM SUNDAY...BETTER AGREEMENT IN MEDIUM RANGE GUIDANCE
TODAY. GFS AND ECMWF OPEN A SRN STREAM WAVE AND MOVE IT ACROSS THE
SERN US DURING THE FRIDAY TIME FRAME. THEY ALSO BOTH HAVE A MILLER-A
LOW MOVING ALONG THE GULF COAST THU WHICH THEN RIDES UP THE EAST
COAST FRI. THIS BRINGS QUITE A BIT OF MOISTURE INTO THE AREA OVER A
DAMMING SFC HIGH PRESSURE RIDGE. PRECIP SLOWLY MOVES IN WED NITE...
BECOMES WIDESPREAD THU AND THU NITE...THEN TAPERS OFF FRI. COULD SEE
SOME WINTRY MIX ACROSS THE HIGHEST ELEVATIONS OF THE NRN MTNS AS
PRECIP MOVES IN LATE WED NITE. HOWEVER...DO NOT EXPECT ANY
SIGNIFICANT ACCUMS ATTM. TEMPS WILL BE BELOW NORMAL THU AND FRI.
ZONAL FLOW DEVELOPS SAT AND SUN. GUIDANCE KEEPS THE FCST DRY AS A
SFC LOW AND ASSOCIATED WARM FRONT REMAIN NORTH OF THE AREA. TEMPS
SAT RISE TO NEAR NORMAL THEN AROUND NORMAL FOR SUN.
&&
.AVIATION /22Z SUNDAY THROUGH FRIDAY/...
AT KCLT...LATEST LAPS CAPE ANALYSIS SHOWS 500 TO 600 J/KG FOR NEARBY
SFC BASED VALUES LATE THIS AFTN. GIVEN THE CONVECTION ONGOING OVER
THE NW PIEDMONT AND ADDITIONAL WEAK ACTIVITY MOVING NE TOWARD THE
CLT METRO AREA...WILL KEEP THE TEMPO TS GOING 22Z TO 00Z...WITH
BROADER SHOWER COVERAGE THROUGH THE EVENING HOURS. TEMPO MVFR CLOUDS
ARE LIKELY IN PRE/FRONTAL AIRMASS TONIGHT...WITH THE COLD FRONT
PASSAGE LIKELY OCCURRING TOWARD DAYBREAK MONDAY. THIS WILL CAUSE
WINDS TO VEER TO THE NW...AND THE CIG TO RISE TO VFR BEFORE ERODING.
ELSEWHERE...TS CHANCES REMAIN BEST AT KHKY THROUGH 23Z...WITH MAINLY
TEMPO SHRA ELSEWHERE IN THE WARM SECTOR AIRMASS AHEAD OF THE COLD
FRONT APPROACHING FROM THE NW. WINDS WILL REMAIN GUSTY FROM THE SW
AT THE UPSTATE SITES. CIGS ARE EXPECTED TO REMAIN LOW VFR THROUGH
THE EVENING...BUT WITH TEMPO MVFR PSBL AT TIMES LATE THIS
EVENING/OVERNIGHT UNTIL THE COLD FRONT MOVES THROUGH TOWARD DAYBREAK
MON. THE COLD FROPA WILL VEER WINDS FROM SW TO NW THROUGHOUT...WITH
ANY LINGERING CIGS ERODING. AT KAVL...WINDS WILL REMAIN CHANNELED
FROM THE NW.
OUTLOOK...FAIR WEATHER EXPECTED LATE MON. ANOTHER COLD FRONT MOVES
THROUGH ON TUESDAY...BUT RESTRICTIONS LOOK DOUBTFUL WITH THIS
SYSTEM. DRY HIGH PRESSURE SETTLE OVER THE AREA ON WEDNESDAY. A GULF
COAST SYSTEM WILL SPREAD CIGS AND PRECIP OVER THE AREA ON THU...AND
RESTRICTIONS ARE POSSIBLE.
CONFIDENCE TABLE...
21-03Z 03-09Z 09-15Z 15-21Z
KCLT HIGH 99% HIGH 88% HIGH 91% HIGH 100%
KGSP HIGH 100% HIGH 92% MED 78% HIGH 100%
KAVL HIGH 95% HIGH 81% HIGH 83% HIGH 100%
KHKY HIGH 97% MED 72% HIGH 87% HIGH 100%
KGMU HIGH 100% HIGH 95% MED 73% HIGH 100%
KAND HIGH 100% HIGH 90% MED 79% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...HG/JAT
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...HG/JAT
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
317 PM CDT SUN MAR 31 2013
.SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...FIRST CONCERN IS
CONVECTION TONIGHT. STILL A GOOD DEAL OF UNCERTAINTY WHETHER
ANYTHING GETS INTO THE CWFA THIS EVENING...AND HOW FAR SOUTH IT WILL
MOVE. WILL MAKE LAST MINUTE ADJUSTMENTS ON FORECAST BASED ON RADAR
TRENDS AND 4 KM MODEL TRENDS...BUT THINK ACTIVITY WILL AT BEST
SCRAPE OUR NORTHERN AREAS BEFORE DISSIPATING WITH THE SETTING OF THE
SUN AND THE APPROACH OF MARINE ENVIRONMENT. STILL...TO MATCH UP WITH
SURROUNDING OFFICES WILL GO WITH LOW CHANCE POPS EXTREME NORTHERN
TIER AND SLIGHT CHANCE A BIT FARTHER SOUTH. AM GOING A BIT FARTHER
SOUTH THAN EXPECTING FOR NOW OUT OF RESPECT FOR HRRR MODEL AND ECMWF
(THE LATTER MODEL DID NOT DO SO WELL A FEW DAYS AGO WITH WEEKEND POP
FORECAST SO RESPECT NOT AS GOOD). AFTER ANY CONVECTION WANES...QUIET
WITH ABOVE NORMAL TEMPERATURES AND AM JUST GOING A DEGREE OR TWO (AT
BEST BELOW THIS MORNINGS LOW TEMPERATURES)...GIVEN LIGHTER WINDS
OVERNIGHT AND SOME AREAS OF FOG LIKELY TO OCCUR. SHOULD BE COOLER
MONDAY GIVEN COOLER BOUNDARY LAYER BUT SILL GENERALLY GOING ABOVE
GUIDANCE MOST AREAS AND KEEPING A DRY FORECAST. COULD HAVE SOME
CONVECTION MONDAY NIGHT WHICH COULD DEVELOP NORTH AND WEST OF CWFA
AND DRIFT IN...WITH RICH THETA-E AIR OVER THAT REGION SO HAVE SLIGHT
CHANCE POPS OUT WEST. AGAIN AM GOING ABOVE MOS NUMBERS MONDAY NIGHT.
&&
.MARINE (TONIGHT THROUGH MONDAY NIGHT)...HAVE INCLUDED SEA FOG IN
THE FORECAST...WHICH WILL BE THE MAIN CONCERN FOR AT LEAST THE NEXT
TWO PERIODS IF NOT THE THIRD. WINDS EXPECTED TO REMAIN BELOW SCA
CRITERION...WITH WEAK TO MODERATE EASTERLY WINDS MONDAY AND MONDAY
NIGHT.
&&
.LONG TERM (TUESDAY THROUGH SUNDAY)...THE CHALLENGE WITH THE
EXTENDED FORECAST MAINLY REMAINS WITH RESPECT TO THE POTENTIAL FOR
MUCH NEEDED RAINFALL ON TUESDAY AND WEDNESDAY. 500MB LOW PRESSURE
AND ASSOCIATED TROUGH CURRENTLY OFF THE WEST COAST WILL MOVE INTO
THE SOUTHWESTERN CONUS THROUGH THE EARLY PART OF THE WORK WEEK.
MEANWHILE...PWAT VALUES WILL CONTINUE TO INCREASE ACROSS THE REGION
AS PERSISTENT ONSHORE FLOW PREVAILS AT THE SURFACE AND 850MB WINDS
TURN MORE OUT OF THE SOUTH/SOUTHEAST. TEMPERATURES WILL ALSO CLIMB
ON TUESDAY AFTERNOON WITH AN INCREASE IN CLOUD COVER...HIGH
TEMPERATURES WILL REMAIN ABOVE SEASONAL AVERAGES. CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL BEGIN TO INCREASE BY TUESDAY
AFTERNOON AS DISTURBANCES ON THE SOUTHERN PERIPHERY OF THE MID/UPPER
LEVEL TROUGH APPROACH SOUTH TEXAS. TUESDAY NIGHT INTO WEDNESDAY
MORNING TIME FRAME APPEARS TO BE THE BEST WINDOW FOR WIDESPREAD
SHOWERS AND THUNDERSTORMS AS THE MAIN DISTURBANCE NEARS THE
REGION...AND 850MB WINDS CONTINUE OUT OF THE SOUTH/SOUTHEAST. THIS
SHOULD KEEP DEEP MOISTURE UP TO 700MB-800MB ACROSS SOUTH TEXAS WITH
PWAT VALUES IN THE 1.4-1.6 INCH RANGE. THE FORECAST MODELS THEN
DIFFER ON THE EXACT TIMING OF A FRONTAL PASSAGE THAT WILL AID IN
DRYING OUT CONDITIONS ALOFT AND PUT AND END TO RAIN CHANCES. HAVE
WENT WITH A BLEND OF MAINLY THE GFS/ECMWF AND HAVE THE FRONTAL
BOUNDARY SLOWLY SLIPPING DOWN INTO SOUTH TEXAS WEDNESDAY AFTERNOON
AND OFFSHORE DURING THE EVENING HOURS. WILL CONTINUE LINGERING
SHOWERS OVER EASTERN AREAS AND OVER THE OFFSHORE WATERS THROUGH
WEDNESDAY NIGHT. CONDITIONS DRY OUT ALOFT AND SURFACE MOISTURE
PUSHES OUT WITH NORTHERLY FLOW DEVELOPING IN WAKE OF THE FRONTAL
PASSAGE. THIS WILL COOL TEMPERATURES WEDNESDAY NIGHT THROUGH FRIDAY
MORNING BEFORE ONSHORE FLOW RESUMES AS SURFACE HIGH PRESSURE QUICKLY
SHIFTS EASTWARD. FRIDAY AND BEYOND...TEMPERATURES WARM WITH NO
MENTION OF PRECIPITATION.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 67 84 68 83 68 / 10 10 10 40 60
VICTORIA 65 83 66 80 62 / 30 10 10 50 80
LAREDO 69 91 69 87 66 / 10 10 20 40 40
ALICE 66 88 67 85 67 / 10 10 10 40 50
ROCKPORT 67 78 68 76 66 / 10 10 10 40 70
COTULLA 67 88 67 84 64 / 30 10 20 50 50
KINGSVILLE 67 87 68 83 69 / 10 10 10 40 50
NAVY CORPUS 69 77 69 79 69 / 10 10 10 40 60
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...SHORT TERM
RG/82...LONG TERM
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
100 PM CDT SUN MAR 31 2013
.DISCUSSION...
18Z TAF DISCUSSION BELOW.
&&
.AVIATION...
MAIN ISSUE WILL BE CONVECTION THE NEXT 6-9 HRS OVER SE TX.
FRONTAL BOUNDARY PUSHING INTO THE AREA MAY INITIATE A FEW STORMS
AND ALREADY SEE THAT NEAR KUTS. HRRR MODEL SEEMS TO HAVE A GOOD
HANDLE ON CONVECTION SO FAR. ITS GUIDANCE SUGGESTS INCREASED
THREAT THROUGH THE AFTERNOON AS SHORTWAVE TROUGH IN W TX MOVES
EAST THIS AFTERNOON. WILL GO WITH VCTS FOR ALL AREAS AND LIKELY
AMEND AS STORMS DEVELOP. SHOULD A LINE OF STORMS DEVELOP...MAY BE
ABLE TO GIVE BETTER TIMING OF CONVECTION IN TAFS. DO EXPECT
ACTIVITY TO DIMINISH FROM 00-02Z THIS EVENING. SHOULD THERE BE
DECENT RAINFALL...THINK THAT WITH LIGHT WINDS COULD GET SOME FOG
LIMITING VSBY. MODELS ALSO HINT AT ANOTHER ROUND OF VERY LOW CIGS.
WILL GO WITH MVFR/IFR CIGS FOR MOST SITES TONIGHT INTO TOMORROW
MORNING. THINK CIGS SHOULD GO VFR LATE MORNING TOMORROW THROUGH
AFTERNOON.
39
&&
.PREV DISCUSSION... /ISSUED 1131 AM CDT SUN MAR 31 2013/
DISCUSSION...
NOT A LOT OF CHANGES TO THE GOING FCST FOR THE UPDATE. STILL KEEP-
ING A CLOSE EYE ON THE CONVECTION ALONG THE FRONTAL BOUNDARY THAT
IS MOVING INTO OUR NRN MOST ZONES. LOOKS LIKE SOME WEAKENING OVER
THE TRAILING END OF THE LINE AS IT APPROACHES HOUSTON COUNTY WITH
THE STRONGEST ACTIVITY FURTHER E/NE ON THE LINE. NO REAL ARGUMENT
WITH THE IDEA OF THIS BOUNDARY LINGERING OVER THE NRN PORTIONS OF
THE CWA AS THE CONVECTION CONTINUES TO DIE OFF. SHORT RANGE PROGS
STILL SHOWING ADDITIONAL DEVELOPMENT LATE THIS AFTN/EARLY EVENING
WITH THE APPROACH/PASSAGE OF A SHORTWAVE. SEEING HINTS OF THIS AS
PER RADAR/SATELLITE LOOPS OVER SOUTH CENTRAL TX ATTM. COULD BE AN
ACTIVE LATTER PART OF THE SHIFT HOPPING INTO THE NEXT ONE. 41
PREV DISCUSSION... /ISSUED 429 AM CDT SUN MAR 31 2013/
SOUTHEAST TEXAS CLOSES OUT THE MONTH OF MARCH WITH A CHANCE OF
MAINLY AFTERNOON THROUGH EARLY EVENING SHOWERS AND THUNDERSTORMS
ASSOCIATED WITH THE APPROACH OF A WEAK COLD FRONT FROM THE NORTH
AND AN UPPER LEVEL DISTURBANCE FROM THE WEST. CONDITIONS APPEAR TO
BE FAVORABLE FOR SOME OF THE STORMS TO BECOME STRONG OR
SEVERE...MAINLY ALONG AND NORTH OF INTERSTATE 10. RAIN CHANCES
WILL BE DECREASING OVERNIGHT...AND SOME LOCATIONS MIGHT END UP
DEALING WITH SOME FOG DEVELOPMENT. MONDAY LOOKS QUIET. RAIN
CHANCES COME BACK INTO THE FORECAST BEGINNING MONDAY NIGHT AND
TUESDAY AS MOISTURE LEVELS BEGIN TO RISE...AND THE BEST CHANCE OF
SHOWERS AND THUNDERSTORMS LOOKS LIKE IT MIGHT BE FOCUSING ON A
TUESDAY NIGHT THROUGH WEDNESDAY AFTERNOON TIME PERIOD AS IMPULSES
ASSOCIATED WITH THE LOW CURRENTLY OFF THE CALIFORNIA COAST MOVE
ACROSS THE STATE. PORTIONS OF OUR AREA LOOK TO HAVE THE POTENTIAL
TO SEE AN INCH OR TWO OF RAIN AROUND MID WEEK WITH THE GREATEST
AMOUNTS POSSIBLY FOCUSING NEAR THE COAST OR OFFSHORE. THIS EARLY
MARCH STORM SYSTEM EDGES OFF TO THE EAST ON THURSDAY...AND A
COOLER AND DRIER AIR MASS SETTLES INTO THE AREA TO CLOSE OUT THE
WEEK. WARMER TEMPERATURES ARE EXPECTED OVER THE WEEKEND AS WINDS
COME BACK AROUND TO THE SOUTH AND SOUTHEAST. 42
CLIMATE...
HOW DRY WILL MARCH END UP?
- FOR IAH...THE MONTHLY RAINFALL TOTAL OF 0.54 INCHES CURRENTLY RANKS
AS THE 6TH DRIEST MARCH ON RECORD. IAH NEEDS 0.24 INCHES OF RAIN TODAY
TO END UP OUT OF THE TOP 10. IAH`S DRIEST MARCH ON RECORD IS A
TRACE OF RAIN IN 1916.
- FOR HOU...THE MONTHLY RAINFALL TOTAL OF 0.56 INCHES CURRENTLY RANKS
AS THE 6TH DRIEST MARCH ON RECORD. HOU NEEDS 0.32 INCHES OF RAIN TODAY
TO END UP OUT OF THE TOP 10. HOU`S DRIEST MARCH ON RECORD IS 0.07 INCHES
IN 1953.
- FOR GLS...THE MONTHLY RAINFALL TOTAL OF 0.19 INCHES CURRENTLY RANKS
AS THE 4TH DRIEST MARCH ON RECORD. GLS NEEDS 0.20 INCHES OF RAIN TODAY
TO END UP OUT OF THE TOP 10. GLS`S DRIEST MARCH ON RECORD IS 0.06 INCHES
IN 1953.
42
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 79 62 81 60 75 / 60 30 10 30 60
HOUSTON (IAH) 78 62 81 62 74 / 50 40 10 30 60
GALVESTON (GLS) 76 64 76 65 71 / 30 30 10 20 50
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...39
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1254 PM CDT SUN MAR 31 2013
.DISCUSSION...SEE 18Z AVIATION DISCUSSION.
&&
.AVIATION...MODELS DO NOT AGREE ON WHETHER WE WILL HAVE DENSE FOG
WITH STRATUS...OR LIGHT FOG AND STRATUS. GFS HAS LIGHT BOUNDARY
LAYER WINDS (MORE FOG) AND NAM HAS STRONGER WINDS (MORE
STRATUS/LIGHT FOG). WITH EASTERLY FLOW EXPECTED TOWARD MORNING AND
BEING RELATIVELY WEAK...AM GOING TO GO WITH FOG GENERALLY NOT
DENSE BUT WITH LOW STRATUS. WITH EAST WINDS...FOG AND STATUS
LIKELY TO BE SIMILAR AT KCRP (COULD GET SOME SEA FOG MOVING
INLAND) AS AT KALI (MORE FOG-PRONE AREA). OVERALL...WILL BEGIN
SEEING MVFR CONDITIONS BY 06Z EASTERN TAFS AND LIFR (AT LEAST
TEMPO) BETWEEN 08Z AND 12Z. FOR KLRD...WILL SEE MVFR/IFR
CONDITIONS AROUND 08Z. CONDITIONS SHOULD IMPROVE TO VFR BY 16Z ALL
TERMINALS EXCEPT KVCT WHERE WILL HAVE MVFR BY 16Z AND THEN THROUGH
THE END OF THE FORECAST. CONCERNING CONVECTION...THINK IT WILL
STAY OUT OF THE TERMINALS TONIGHT (SPC 4KM MODEL HAS CONVECTION
GOING TO THE COAST BUT THINK IT IS NOT ACCOUNTING FOR MORE STABLE
MARINE LAYER ENVIRONMENT...MOST OTHER MODELS KEEPING IT OUT OF
TERMINALS). IF ANY CONVECTION WOULD OCCUR IT WOULD BE KVCT AND
CONFIDENCE IN ACTIVITY GETTING THERE TOO LOW AT THIS TIME FOR EVEN
A VCTS. WILL MONITOR SITUATION HOWEVER.
&&
.PREV DISCUSSION... /ISSUED 1000 AM CDT SUN MAR 31 2013/
DISCUSSION...JUST MADE SOME MINOR MODIFICATIONS TO GRIDS (MAINLY
MOISTURE AND MINOR AT THAT) BUT OTHERWISE NO REAL CHANGES NEEDED.
NEW NAM12 RUN HAS CONVECTION APPROACHING AREA AROUND 00Z BUT THEN
WEAKENS IT AS IT MOVES SOUTHWARD. HRRR MODEL HAS CONVECTION TOO
BUT FARTHER EAST AND PUSHES IT A BIT FARTHER SOUTH (BUT NOT MUCH).
ALL IN ALL...THIS JUSTIFIES MAINTAINING THE 20 POPS OVER THE
NORTHERN TIER OF AREA AS PREVIOUSLY FORECAST FOR TODAY. WILL LET
TEMPERATURE FORECAST RIDE. WILL UPDATE PFM AND AFM TEXT PRODUCTS
BUT ZFPCRP SEEMS OK FOR NOW.
MARINE...HAVE HAD OBSERVATIONS OF FOG/SEA FOG OVER THE GULF
WATERS THIS MORNING...PATCHY DENSE AT TIMES. HAVE WRITTEN MARINE
WEATHER STATEMENT TO HIGHLIGHT CONCERN MAINLY FOR TONIGHT AND
MONDAY...AS SOME OBSERVATIONS HAVE DEW POINTS AROUND 70F THIS
MORNING AND SHELF TEMPS STILL IN THE MID/UPPER 60S. WILL LOOK AT
LATER PERIODS ONCE NEW MODEL RUNS AND OBSERVATIONS COME IN.
PREV DISCUSSION... /ISSUED 626 AM CDT SUN MAR 31 2013/
DISCUSSION...UPDATE FOR 12Z AVIATION.
AVIATION...BKN-OVC 500-1500 STRATUS DECK IN PLACE ACROSS EASTERN
PORTIONS OF SOUTH TEXAS THIS MORNING...ALONG A HBV-BEA-VCT LINE
EAST TO THE COAST. STRATUS DECK WILL GRADUALLY ERODE 15Z-18Z WITH
VFR CONDITIONS FOR THIS AFTERNOON. S TO SE WINDS 6-12 KTS INCREASING
TO 10-15 KTS AFTER 15Z...AND INCREASING FURTHER AT CRP 15-20 KTS
WITH GUSTS TO 25 KTS THIS AFTERNOON. IFR CIGS WILL QUICKLY
RE-DEVELOP EARLY THIS EVENING FROM E TO W.
PREV DISCUSSION... /ISSUED 351 AM CDT SUN MAR 31 2013/
SHORT TERM (TODAY THROUGH MONDAY)...MID AND UPPER LEVEL SHORTWAVE
DIVING SOUTHEAST THROUGH SOUTH-CENTRAL PLAINS EARLY THIS MORNING
WITH A SECOND SHORTWAVE TROUGH ACROSS NEW MEXICO TRACKING EAST INTO
TEXAS. COLD FRONT HAS ENTERED THE PANHANDLE AND WILL PUSH SOUTH
THROUGH WEST-CENTRAL TEXAS THIS MORNING. SOUTH OF THE FRONT ACROSS
SOUTH TEXAS...WARM CONDITIONS WILL PREVAIL FOR THIS EASTER SUNDAY.
INITIALLY MODELS INDICATING SOME SLIGHT DRYING TAKING PLACE NOW
THROUGH 18Z IN THE 925MB-850MB LAYER...BUT THEN MOISTENING BACK UP
ACROSS THE CENTRAL AND NORTHERN COUNTIES LATE THIS AFTERNOON...IN
ADVANCE OF THE WEAKENING COLD FRONT ENTERING THE HILL COUNTRY AND
SOUTH-CENTRAL TEXAS. BACKING LOW LEVEL FLOW AHEAD OF THE SYSTEM
MAY YIELD AN ISOLATED SHOWER OR THUNDERSTORMS ACROSS THE CENTRAL
COUNTIES LATER THIS AFTERNOON WHERE PWATS POOLED AROUND 1.5"...BUT
THE MAIN AREA TO WATCH WILL BE UPSTREAM CONVECTION ACROSS THE EWX
CWA CLOSER TO THE FRONT AND SECOND SHORTWAVE. HI RESOLUTIONS
MODELS HAVE BEEN INDICATING THIS CONVECTION POSSIBLY MAKING IT
INTO THE FAR NORTHERN CWA LATE AFTERNOON/EARLY EVENING...WITH 00Z
ECMWF AND 00Z NAM12 ALSO HINTING AT THIS. SHOULD NOTE THAT THE 00Z
4KM ARW/NMM WAS SHOWING CONVECTIVE COMPLEX REACHING THE COAST THIS
EVENING BUT AM DISCOUNTING THIS FOR THE TIME BEING...AND THINKING
THAT IF CONVECTION MAKES IT INTO THE AREA...IT WOULD LIKELY BE
CONFINED TO NORTHERN AND WESTERN AREAS OF THE CWA...AS CIN WOULD
BE RAPIDLY INCREASING IN THE EARLY EVENING ACROSS THE COASTAL
PLAINS BEHIND THE SEA-BREEZE. GIVEN THE INSTABILITY FORECAST TO
DEVELOP LATE AFTERNOON ACROSS THE BRUSH COUNTRY (1700-2000 J/KG
CAPE)...STEEP MID LEVEL LAPSE RATES...AND DEEP LAYER SHEAR OF
AROUND 50 KTS OVER THE CWA...ISOLATED STRONG TO SEVERE STORMS ARE
POSSIBLE. SPC HAS IN FACT EXTENDED SOUTHWARD THE SLIGHT RISK INTO
THE CWA...ALONG AND NORTH OF A LINE FROM JUST NORTH OF LAREDO TO
ALICE TO VICTORIA. IF CONVECTION DOES DEVELOP OVER OR INTO THE CWA
IT SHOULD DIMINISH LATE IN EVENING WITH LOSS OF HEATING. SLIGHTLY
COOLER TONIGHT...WITH WINDS BACKED EAST AND NORTHEAST. PATCHY TO
AREAS OF FOG DEVELOPING OVERNIGHT. SLIGHTLY COOLER (BUT STILL
WARM) ON MONDAY ACROSS SOUTH TEXAS. ECMWF INDICATING QPF ACROSS
THE RIO GRANDE PLAINS AND EDWARDS PLATEAU ON MONDAY...WHERE PWATS
STILL POOLED NEAR 1.5"...BUT AM KEEPING FORECAST DRY DUE TO LOW
CONFIDENCE.
LONG TERM (MONDAY THROUGH SATURDAY)...CHALLENGING FORECAST
CONTINUES THROUGH THE EXTENDED...HOWEVER EACH NEW MODEL RUN BRINGS
THE DIFFERENT GUIDANCE OPTIONS CLOSER TOGETHER...WELL...EXCEPT FOR
THE NAM...WHICH IS A PRETTY FAR OUTLIER. WILL FOCUS MAINLY TOWARD
THE GFS AND ECMWF THROUGHOUT THE FORECAST. THESE HAVE COME IN QUITE
GOOD AGREEMENT WITH FRONTAL PASSAGE TIMING BEING WEDNESDAY
AFTERNOON. (THE NAM MUCH FASTER THAN THIS...AND THE CANADIAN A BIT
SLOWER.) TOUGH PART OF THE FORECAST IS PRECIP TIMING AND AMOUNTS.
COULD SEE SOME ISOLATED ACTIVITY BY MONDAY NIGHT...BUT BETTER
CHANCES BEGIN ON TUESDAY. WITH FAVORABLE ISENTROPIC LIFT PATTERN
SETTING UP...AND PLENTY OF MOISTURE POOLING ACROSS THE AREA...SEEMS
A GOOD CHANCE FOR A WIDESPREAD RAIN ACROSS SOUTH TEXAS. WITH A
SUFFICIENTLY WEAKENED CAP WILL HAVE THE POTENTIAL FOR THUNDERSTORMS
TUESDAY AND WEDNESDAY. ONE THING NOTABLE SEPARATING THIS EVENT FROM
OTHER FRONTS/PRECIP CHANCES WE/VE HAD RECENTLY...WINDS IN THE LOWER
LEVELS OF THE ATMOSPHERE STAY SOUTHEAST OR SOUTH THROUGH TUESDAY
BEFORE VEERING SOUTHWEST WEDNESDAY MORNING. THIS WOULD ALLOW FOR A
MOIST/SATURATED LAYER UP TO AROUND 850MB. HAVE NOT MADE MUCH CHANGE
TO PREVIOUS POP FORECAST...MAXING OUT AT 70 POPS ON TUESDAY NIGHT
AND EARLY WEDNESDAY...THEN TRAILING OFF WEDNESDAY NIGHT. UNLESS
FRONTAL TIMING BACKS UP FURTHER...THINK PRECIP SHOULD BE DONE BY
SUNRISE THURSDAY AS UPPER LOW/TROUGH LIFTS OUT OF THE AREA. TOUGH TO
MAKE A SPECIFIC CALL ON PRECIP TOTALS AT THIS TIME...BUT CERTAINLY
HAVE THE POTENTIAL FOR AN INCH OR MORE OF RAIN FOR SOME OF US...BEST
CHANCES BEING THE NORTHEAST PORTION OF THE FORECAST AREA. CURRENTLY
HAVE A GENERALLY RANGE OF ONE HALF TO ONE INCH ACROSS THE CWA.
AS FAR AS TEMPERATURES...WARMED THINGS UP A BIT ON WEDNESDAY WITH
FRONT NOT COMING THROUGH UNTIL THE AFTERNOON...HOWEVER WITH NEARLY
OVERCAST SKIES AND PRECIP IN THE AREA WILL BE SEVERAL DEGREES COOLER
THAN TUESDAY. WILL ONLY REALLY SEE ONE DAY OF NORTHERLY WINDS/COLD
ADVECTION BEHIND THE FRONT BEFORE HIGH PRESSURE RIDGE PUSHES OFF TO
THE EAST BY FRIDAY. THUS A COOL DAY ON THURSDAY...BUT GRADUALLY
WARMING TEMPS FRIDAY INTO THE WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 87 64 85 68 81 / 10 10 10 10 40
VICTORIA 83 61 83 65 78 / 20 20 10 20 50
LAREDO 94 68 89 68 86 / 10 10 10 20 40
ALICE 91 64 89 68 82 / 10 10 10 10 40
ROCKPORT 78 64 77 66 77 / 10 10 10 20 40
COTULLA 89 64 88 67 84 / 20 30 10 20 50
KINGSVILLE 89 64 86 67 83 / 10 10 10 10 40
NAVY CORPUS 81 66 79 68 79 / 10 10 10 10 40
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...AVIATION