Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/02/13
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 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 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
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 PEACHTREE CITY GA
747 PM EDT MON APR 1 2013
.UPDATE...
TWO WEAK BOUNDARIES ACROSS THE CWFA THIS EVENING...BOTH WEAK COLD
FRONTS. THE FIRST FRONT IS ACROSS NORTHERN GA AND THE SECOND IS
ACROSS THE SOUTHERN CWFA. NO REAL MOISTURE ASSOCIATED WITH EITHER
OF THESE FEATURES OTHER THAN SOME CU...SO HAVE REMOVED THE MENTION
OF POPS. ANY SCT CU SHOULD ALSO DISSIPATE WITH SUNSET.
TWEAKED HOURLY TEMPS A BIT...THEY WERE NOT FALLING OFF AS FAST AS
FORECAST. ADJUSTED THE MIN TEMPS A FEW HOURS...WITH THE METRO AREA
A COUPLE OF DEGREES WARMER.
&&
.PREV DISCUSSION... /ISSUED 350 PM EDT MON APR 1 2013/
..BRIEF DRY PERIOD BEFORE RAIN RETURNS MID WEEK...
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
LATEST SURFACE ANALYSIS SHOWS SEMI PERMANENT SURFACE TROUGH FROM
JUST SOUTH OF ATHENS THROUGH COLUMBUS. ALONG AND SOUTH OF THIS
FEATURE MOISTURE SURFACE CONVERGENCE HAS RESULTED IN SCATTERED TO
BROKEN CU DEVELOPMENT BUT SHOWER ACTIVITY HAS REMAINED OUTSIDE OF
THE FORECAST AREA. FURTHER NORTH...SURFACE FRONT CONTINUES TO SAG
INTO NORTH GA WITH MOISTURE POOLING ALONG ITS LEADING EDGE AS WELL
AND ADDITIONAL CLOUD DEVELOPMENT THE RESULT.
THIS SHOULD REMAIN JUST CLOUDS WITH NO PRECIP FOR THIS EVENING AS
MAIN FOCUS WILL BE ON SOUTHERN TROUGH AND IT AFFECTS ON CENTRAL
GEORGIA. LOOKING AT THE LATEST RAP ANALYSIS OF CAPE IN THIS
VICINITY AND WE SEE 500 J/KG TO 1000 J/KG OF AVAILABLE
ENERGY...SLIGHTLY HIGHER THAN MODEL PROJECTIONS. STILL LOOKING AT
500MN TEMPS IN THE VERY COLD RANGE OF -17C IN THIS AREA SO ANY
SUSTAINED UPDRAFTS WILL BE CAPABLE OF PRODUCING LARGE HAIL.
ACTIVITY WILL SHIFT EAST QUICKLY THIS EVENING WITH CLEARING
CONDITIONS TAKING PLACE. STILL SOME GRADIENT IN PLACE ACROSS THE
AREA WHICH WILL PREVENT OPTIMUM RADIATIONAL COOLING CONDITIONS.
WENT WITH A MAV/MET BLEND FOR THE OVERNIGHT TEMPS WHICH WILL BE
TRICKY TO THE SOUTH BASED ON HOW FAST CLOUDS CLEAR.
SURFACE FRONT LOOKS TO STALL ACROSS NORTH GEORGIA TUESDAY AND
IMPULSES OF ENERGY BEGIN TO ROUND PERIPHERY OF EAST COAST TROUGH.
THIS SHOULD ALLOW A FEW LIGHT SHOWERS TO DEVELOP ACROSS EXTREME
NORTH GEORGIA AND HAVE INCLUDED IN THIS GRID PACKAGE. AS HIGH
BRIDGES ACROSS THROUGH TUESDAY NIGHT...MAY SEE FRONT SAG FURTHER
SOUTH AND TAKE 20 POPS ALONG WITH IT INTO THE REMAINDER OF NORTH
GEORGIA.
DEESE
LONG TERM /WEDNESDAY THROUGH MONDAY/...
MAIN CONCERN FOR THE EXTENDED REMAINS THE SYSTEM MOVING THROUGH
THE STATE ON WEDNESDAY INTO THE END OF THE WORK WEEK.
DISCREPANCIES STILL REMAIN BETWEEN THE EURO AND GFS AS FAR AS
TIMING OF THE SYSTEM LEAVING THE CWA. THE 12Z MODELS ARE
STRIKINGLY SIMILAR TO THEIR OOZ COUNTERPARTS. AS SUCH...WAS NOT
ABLE TO NAIL DOWN AN ACCURATE END TO THE RAIN THIS WEEK. ACCORDING
TO HPC MODEL DISCUSSIONS THE EURO IS AN OUTLIER...MOVING THE
SYSTEM FURTHER SOUTH AND IS SLOWER. THAT SAID THEY DECIDED TO WITH
A BLEND BETWEEN THE 00Z EURO AND THE 06Z GEFS. WITH THIS MUCH
UNCERTAINTY DECIDED TO ONLY CHANGE THE COVERAGE OF THUNDER ON
WEDNESDAY AND LEAVE THE REST OF THE FORECAST ALONE. DID LOWER
TEMPS ON THURSDAY AS A PSEUDO WEDGE BUILDS IN. CLOUDS AND RAIN IN
ASSOCIATION WITH THIS WEDGE SHOULD HELP TO KEEP TEMPS LOW. HAVE
INCLUDED PREVIOUS EXTENDED BELOW/
ARG
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... POTENTIAL FOR A HEAVY
RAIN/SEVERE WEATHER EVENT SETTING UP IN THE THURSDAY TO THURSDAY
NIGHT TIME FRAME. MODELS SIMILAR WITH SPREADING DEEPER MOISTURE
INTO THE AREA LATE WEDNESDAY BUT THE MAIN PRECIP PERIOD LOOKS TO
BE WEDNESDAY NIGHT THRU THURSDAY NIGHT. AN OVERRUNNING PATTERN
WILL SET LATE WEDNESDAY/WEDNESDAY NIGHT WITH MODELS DEVELOPING A
WARM FRONT ALONG THE GULF COAST. SURFACE LOW PRESSURE DEVELOPS
OVER THE WESTERN GULF AND MOVES TO THE WESTERN FL PANHANDLE LATE
THURSDAY AND THEN ACROSS CENTRAL TO S GA THURSDAY NIGHT/FRIDAY.
THE GFS IS FASTER WITH THIS PROGRESSION THAN THE EUROPEAN. THIS
TRACK COULD MOVE THE WARM FRONT INTO THE SE CWA AND GIVE POTENTIAL
FOR SEVERE THUNDERSTORMS MAINLY THURSDAY NIGHT. IT WILL ALSO GIVE
POTENTIAL FOR HEAVY RAIN ACROSS A LARGE PORTION OF EAST GEORGIA
AND MODELS IN GENERAL ARE LESS GUN-OH WITH PRECIP AMOUNTS WITH A
LARGE AREA OF 1-2 INCHES FORECAST. THE UPPER TROUGH MOVES ACROSS
THE AREA ON FRIDAY AND THE GFS IS FASTER WITH THIS PROGRESSION
THAN THE EUROPEAN. THE AIRMASS DRIES OUT FOR SATURDAY AND MOSTLY
LIKELY SUNDAY WITH THE EUROPEAN INDICATING SOME MOISTURE
ASSOCIATED WITH A SHORT WAVE ON SUNDAY...MOST SO FOR N GA. FOR NOW
WILL KEEP THINGS DRY AND MONITOR THE PROGRESSION. A SHORT WAVE
RIDGE BUILDS FOR MONDAY WITH THE EUROPEAN CONTINUING TO SHOW MORE
MOISTURE SKIRTING OVER N GA THAN THE GFS.
BDL
AVIATION...
00Z UPDATE...
VFR FORECAST ON TAP FOR THE PERIOD. ANY LINGERING CU WILL
DISSIPATE WITH SUNSET THIS EVENING. A FEW/SCT DIURNAL CU WILL ALSO
BE POSSIBLE TOMORROW AFTER WITH ANY CIGS WELL ABOVE 3 KFT. MAIN
ISSUE WILL BE THE WINDS. NW WINDS WILL CONTINUE OVERNIGHT. A BRIEF
PERIOD OF N FLOW IS POSSIBLE DURING THE MORNING BUT WINDS WILL
SHIFT BACK TO THE NW BY THE AFTERNOON.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM ON WIND SHIFT.
HIGH ON REMAINING ELEMENTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 42 69 41 64 / 10 10 20 20
ATLANTA 47 67 44 64 / 5 5 20 20
BLAIRSVILLE 37 58 35 63 / 10 10 20 20
CARTERSVILLE 41 65 40 64 / 5 10 20 20
COLUMBUS 51 75 50 70 / 5 5 5 30
GAINESVILLE 44 65 43 61 / 10 10 20 20
MACON 45 75 44 69 / 5 5 5 30
ROME 38 65 38 64 / 5 10 20 20
PEACHTREE CITY 40 70 42 65 / 5 5 20 30
VIDALIA 55 76 51 74 / 20 0 5 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ATWELL
LONG TERM....ATWELL
AVIATION...ATWELL
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 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...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 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 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 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 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 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
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 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...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 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
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 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 GRAND FORKS ND
945 PM CDT MON APR 1 2013
.UPDATE...
ISSUED AT 945 PM CDT MON APR 1 2013
SHORTWAVE AND ASSOCIATED CLOUDS CONTINUE TO APPROACH THE REGION
FROM THE NORTHWEST. TIMED CLOUDY SKIES INTO THE FA BY LATER
TONIGHT AND INTO TUESDAY MORNING. SOME FLURRIES REPORTED
UPSTREAM...BUT MODELS DRY THIS ACTIVITY AS IT APPROACHES. NO
CHANGES NEEDED TO MIN TEMPS AS ANY CLOUD COVER WILL ARRIVE WELL
AFTER MIDNIGHT. MINOR ADJUSTMENTS TO THE HOURLY TEMPERATURE GRIDS
ACROSS THE FAR NW FA TO ACCOUNT FOR CLOUDS ARRIVING JUST BEFORE
SUNRISE.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 317 PM CDT MON APR 1 2013
TONIGHT...MAIN FORECAST CHALLENGE WILL BE CLOUDS AND TEMPS.
MODELS SEEM TO BE IN FAIR AGREEMENT SO WILL CONTINUE TO USE A
MODEL BLEND. NEVER SAW MUCH FOR CLOUD DEVELOPMENT TODAY SO WILL
START OFF THE NIGHT NEARLY CLOUD FREE. THERE IS AN UPSTREAM WAVE
OVER CENTRAL SASKATCHEWAN WITH SOME CLOUDS AND EVEN SOME FLURRIES
OR LIGHT SNOW ASSOCIATED WITH IT. AMERICAN MODELS HAD BEEN TRYING
TO HOLD SOME OF THIS LIGHT PCPN TOGETHER ALL THE WAY INTO THE
NORTHERN FA LATE. 12Z RUNS OF THE NAM/GFS STILL HOLD IT TOGETHER
BUT SEEM TO ERODE IT EITHER BEFORE IT GETS INTO OUR FA...WHILE
THE ECMWF REMAINS DRY. THEREFORE WILL KEEP THE FORECAST DRY
TONIGHT. AS FAR AS TEMPS GO SFC HIGH PRESSURE STILL REMAINS OVER
THE FA WITH SOME PRETTY LIGHT WINDS. WILL STICK WITH LOWS TONIGHT
FAIRLY SIMILAR TO THOSE FROM THIS MORNING.
TUE...SFC HIGH REMAINS IN CLOSE PROXIMITY TO THE RED RIVER VALLEY
KEEPING WINDS ON THE LOW SIDE AGAIN. LINGERING CLOUD COVER MAY
HAVE SOME INFLUENCE ON HIGHS FOR THE DAY. GENERALLY KEPT HIGHS
ABOUT 5F WARMER THAN TODAY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 317 PM CDT MON APR 1 2013
TUE NIGHT-THU...WED IS STILL ON TRACK TO BE THE WARMEST DAY OF THE
WEEK WITH 850MB TEMPS REACHING UP INTO THE +6C TO +8C RANGE OVER
PORTIONS OF THE FA WITH A LITTLE STEADIER SOUTH WINDS. MAYBE NOT
THE BEST DIRECTION FOR REALLY GOOD WARMING BUT AS THE COLD FRONT
COMES THRU THEY SHOULD SWITCH TO THE WEST THEN NW. STILL LOOKS
LIKE A LITTLE BIT OF PCPN WILL COME THROUGH WITH THE COLD FRONT
BUT TRIED TO NARROW DOWN THE WINDOW A BIT BETTER. SHOULD REALLY BE
A QUICK SHOT ALONG THE FRONT AND TEMPS SHOULD BE WARM ENOUGH TO
KEEP ANY PCPN IN THE LIQUID FORM UNLESS MORE PCPN LINGERS BEHIND
THE FRONT. THU WOULD BE COOLER BEHIND THE FRONT.
THU NIGHT-MON...AN ENERGETIC JET STREAM WITH SOMEWHAT FLATTENED
LONGWAVE RIDGE PATTERN IN THE LATE WEEK THEN TRANSITIONS TO A
BROAD WESTERN TROF OVER THE WEEKEND. THIS PRODUCES A BRIEF RETURN
TO NORTHWEST MID LEVEL FLOW OVER THE AREA ON THURSDAY AND A SUBTLE
/FEW DEGREE/ COOL DOWN BEHIND A SURFACE COLD FRONT. A RETURN
SOUTHERLY BLAYER FLOW IS EXPECTED ON FRIDAY... WITH ALL LONG RANGE
MODELS ANTICIPATING THE ADVANCE OF A COLORADO LOW INTO THE CENTRAL
AND NORTHERN PLAINS BY SATURDAY. A RAIN/SNOW MIX LOOKS QUITE
PROBABLE FOR MUCH OF THE AREA FROM FRIDAY EVENING INTO SATURDAY...
WITH A SOMEWHAT COOLER AND DRIER PATTERN ON SUNDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 633 PM CDT MON APR 1 2013
THERE IS A WEAK SHORTWAVE THAT WILL PASS THROUGH THE REGION
OVERNIGHT AND INCREASE CLOUD COVER. NOT SURE HOW WIDESPREAD THE
CLOUDS WILL BE...OR EXACTLY HOW LOW. JUDGING FROM UPSTREAM
SATELLITE IMAGERY AND RAP GUIDANCE...THERE WILL LIKELY BE A PERIOD
OF BKN CIGS IN THE LOW VFR RANGE (ESPECIALLY ALONG AND WEST OF THE
RED RIVER VALLEY).
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...GODON
LONG TERM...GUST
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
843 PM CDT MON APR 1 2013
.UPDATE...
ISSUED AT 842 PM CDT MON APR 1 2013
LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW MOSTLY
CLEAR SKIES ACROSS WESTERN AND CENTRAL NORTH DAKOTA THIS EVENING.
WATER VAPOR CAPTURES THE SHORTWAVE TROUGH ALOFT SLIDING SOUTHEAST
ALONG THE CENTRAL SASKATCHEWAN/MANITOBA BORDER. LATEST RAP MODEL
CONTINUES TO ADVECT AN 80/90 PERCENT H85-H7 RH FIELD INTO THE
NORTHEASTERN ZONES AFTER MIDNIGHT THROUGH 12Z TUESDAY. THE LATEST
FOG/STRATUS AND IR SATELLITE IMAGERY CONFIRMS THE HIGHER RH FIELD
UPSTREAM. COULD BE A POSSIBLE FLURRY OR TWO NEAR THE ROLLA/BELCOURT
AREA AND TURTLE MOUNTAINS BETWEEN 10Z AND 12Z TUESDAY...BUT NOT
ENOUGH TO WARRANT A MENTION RIGHT NOW. UPDATES WILL MAINLY BE
CENTERED AROUND CURRENT OBS AND TRENDS WITH NO SIGNIFICANT CHANGES
TO CURRENT FORECAST.
UPDATE ISSUED AT 546 PM CDT MON APR 1 2013
LATEST SUITE OF SATELLITE IMAGERY/SURFACE OBSERVATIONS SHOWS
CLEAR SKIES ACROSS WESTERN AND CENTRAL NORTH DAKOTA WITH THE
EXCEPTION OF A SCT/BKN CUMULUS DECK OVER THE HIGHER TERRAIN IN THE
SOUTHWEST...IN CONJUNCTION WITH A LOW LEVEL BAROCLINIC ZONE.
TEMPERATURES WERE IN THE 50S ACROSS SOUTHEAST MONTANA...WITH
TEMPERATURES AROUND 40 IN OUR SOUTHWEST ZONES. OTHERWISE...A
1030MB SURFACE HIGH PRESSURE SITS OVER NORTHERN NORTH DAKOTA THIS
EVENING PRODUCING CLEAR SKIES AND LIGHT WINDS.
FURTHER UPSTREAM...WATER VAPOR IMAGERY SHOWS A WEAK SHORTWAVE
TROUGH ALOFT OVER NORTHEAST SASKATCHEWAN ALONG WITH A SURFACE
REFLECTION/SURFACE TROUGH PER MSAS...ALL MOVING SOUTHEAST WITH
TIME. THIS SHORTWAVE IS FORECAST TO MOVE TO LAKE WINNIPEG BY 06Z
TUESDAY...THEN INTO NORTHERN MINNESOTA BY 12Z TUESDAY. BEST UPWARD
VERTICAL MOTION/H85-H3 OMEGA FIELD IS FORECAST OVER SOUTHERN
MANITOBA DURING THE 06Z-12Z TUESDAY TIME FRAME. HOWEVER THE 18Z
NAM/GFS AND LATEST RAP MODEL PRODUCE A SWATH OF 80 TO 90 PERCENT
H85-H7 RH LATER TONIGHT ASSOCIATED WITH THIS SHORTWAVE. THE
NAM/GFS ALSO PAINT LIGHT QPF OF 0.01 COVERING PORTIONS OF BOTTINEAU
AND ROLETTE COUNTIES BETWEEN 09Z AND 12Z TUESDAY. THE LATEST RAP
MODEL KEEPS THE PRECIPITATION JUST EAST OF BOTTINEAU/ROLETTE
COUNTIES. OBSERVATIONS AND PAST WEATHER IN LOCATION OF CURRENT
SHORTWAVE DOES REVEAL A POCKET OF LOW/MID LEVEL CLOUDS AND A BRIEF
PERIOD OF ISOLATED FLURRIES.
FOR THIS UPDATE...HAVE COLLABORATED WITH NEIGHBORING OFFICES TO
INCREASE THE SKY GRIDS FOR THE NORTHEAST TONIGHT...BUT HOLD OFF
ON ANY MENTION OF PRECIPITATION AS BEST VERTICAL MOTION IS
FORECAST NORTH/EAST. WILL AWAIT THE 00Z MODEL RUNS AND KEEP A
CLOSE EYE ON THE RAP MODEL THIS EVENING FOR ANY CHANGES. UNTIL
OBSERVATIONS SUGGEST SOMETHING DEVELOPING CLOSER TO OUR NORTHERN
BORDER...WILL STAY THE COURSE WITH THE DRY FORECAST. REST OF
FORECAST IS IN GOOD SHAPE.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 346 PM CDT MON APR 1 2013
HIGH PRESSURE WILL GRADUALLY SHIFT EAST OF THE REGION THROUGH THE
PERIOD. DRY CONDITIONS WILL PREVAIL AS A RESULT. BELOW NORMAL
TEMPERATURES WILL CONTINUE THIS AFTERNOON AND TONIGHT.
HOWEVER...RETURN FLOW DEVELOPING ACROSS THE REGION COMBINED WITH NO
SNOW PACK SOUTHWEST OF THE MISSOURI WILL ALLOW TUESDAY AFTERNOON
HIGHS TO BE ABOVE NORMAL SOUTHWEST. BELOW NORMAL TEMPERATURES WILL
CONTINUE NORTH AND EAST OF THE MISSOURI RIVER...WHERE THE SNOW PACK
IS LOCATED.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 346 PM CDT MON APR 1 2013
THE MAIN FORECAST CHALLENGES FOR THE EXTENDED PERIOD INCLUDE
PRECIPITATION CHANCES AND PRECIPITATION TYPE. 12Z SUITE OF MODEL
SOLUTIONS ARE IN AGREEMENT EARLY IN THE PERIOD...WITH SOLUTIONS
DIVERGING LATE THIS WEEK.
WARM AIR ADVECTION WILL CONTINUE ACROSS THE AREA TUESDAY NIGHT AND
WEDNESDAY AHEAD OF A UPPER LEVEL WAVE/SURFACE LOW PRESSURE SYSTEM
THAT IS FORECAST TO PASS OVER NORTH DAKOTA. WARM H850
TEMPERATURES OF +6 TO +10C WILL BE FIRMLY IN PLACE WEDNESDAY AS
PRECIPITATION BEGINS ACROSS THE NORTHWEST AND SPREADS SOUTHEAST
ACROSS THE AREA WEDNESDAY. PRECIPITATION WILL BEGIN AS LIGHT
FREEZING RAIN AND TRANSITION TO LIGHT RAIN DURING WEDNESDAY
AFTERNOON. ACROSS THE SOUTHWEST...ISOLATED WEAK THUNDERSTORMS ARE
POSSIBLE...WHERE TEMPERATURES WILL BE IN THE 60S WITH SURFACE BASED
CAPE IN THE 100 TO 200 J/KG ADVERTISED BY THE 12Z NAM. BEFORE
ENDING WEDNESDAY EVENING...A TRANSITION FROM LIGHT RAIN TO A
WINTRY MIX OF SNOW...FREEZING RAIN...AND POSSIBLY SLEET WILL BE
SEEN AS A COLD FRONT MOVES SOUTH FROM CANADA.
COOLER TEMPERATURES WILL BE SEEN WEDNESDAY NIGHT AND THURSDAY...AS
COLD AIR COMMENCES FOLLOWING THE PASSAGE OF THE AFOREMENTIONED
COLD FRONT. HOWEVER...ACROSS THE SNOW LESS AREAS...TEMPERATURES
WILL BE WARMEST WITH TEMPERATURES IN 50S ON THURSDAY. FOR
LOCATIONS ACROSS THE SNOWPACK...TEMPERATURES WILL BE IN THE LOW TO
MID 30S.
STARTING FRIDAY...AN ACTIVE PERIOD OF WEATHER IS EXPECTED
TO START AS A SERIES OF UPPER LEVEL WAVES AND THEIR SURFACE
REFLECTIONS ARE PROGGED TO MOVE ACROSS THE AREA IN NORTHWESTERLY
FLOW. UNCERTAINTY REMAINS IN THE PLACEMENT AND TYPE OF
PRECIPITATION ACROSS NORTH DAKOTA...AS THERE IS DISAGREEMENT
AMONGST THE 12Z MODEL SOLUTIONS. THE 12Z GEM/GFS ARE MORE
AGGRESSIVE WITH QPF ACROSS THE WEST AND CENTRAL VERSUS THE 12Z EC
SOLUTION. THE 12Z EC KEEPS THE BULK OF THE PRECIPITATION FURTHER
NORTH ACROSS SOUTHERN MANITOBA AND SASKATCHEWAN.
AT THIS TIME HAVE UTILIZED A BLEND OF MODEL SOLUTIONS DURING THE
FRIDAY TO MONDAY PERIOD...WHICH GIVE A WIDE ARRAY OF PRECIPITATION
TYPES. AT THIS MOMENT...IT LOOKS LIKE THE SOUTHWEST WILL REMAIN
MOSTLY RAIN AS IT REMAINS IN THE WARM H850 TEMPERATURES OF +4 TO
+8 C. ELSEWHERE...A LIGHT WINTRY MIX OF SNOW...FREEZING RAIN...AND
POSSIBLY SLEET MAY OCCUR. BY SUNDAY EVENING AND
MONDAY...PRECIPITATION TYPE WILL BE SNOW...AS ANOTHER COLD FRONT
DROPS SOUTH OUT OF CANADA. FOLLOWING THE PASSAGE OF THE COLD
FRONT...COLDER H850 TEMPERATURES OF -8 TO -12 C ARE POSSIBLE AT
THE BEGINNING OF NEXT WEEK...AS A SURFACE HIGH PRESSURE STARTS TO
MOVE SOUTH.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING...
ISSUED AT 546 PM CDT MON APR 1 2013
GENERALLY CLEAR SKIES/VFR CONDITIONS WILL PREVAIL OVER WESTERN AND
CENTRAL NORTH DAKOTA THROUGH THE 00Z TAF PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...TM
LONG TERM...LTH
AVIATION...KS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
633 PM CDT MON APR 1 2013
.UPDATE...
ISSUED AT 633 PM CDT MON APR 1 2013
MAIN CONCERN FOR TONIGHT WILL BE CLOUD COVER AND PRECIP CHANCES
ASSOCIATED WITH APPROACHING SHORTWAVE (IN NW FLOW ALOFT). FAIRLY
DRY LOW LEVEL AIRMASS IN PLACE AND THERE SHOULD NOT BE ANY
MEASURABLE PRECIP. SATELLITE IMAGERY INDICATES A FAIR AMOUNT OF
CLOUD COVER ASSOCIATED WITH THE FEATURE. THUS...WILL INCREASE SKY
COVER. NOT SURE EXACTLY HOW WIDESPREAD THE SKY COVER WILL ACTUALLY
BE BY THE TIME THE SHORTWAVE IS OVER THE REGION...AND WILL AWAIT
THE 10 PM UPDATE BEFORE ADJUSTING MIN TEMPS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 317 PM CDT MON APR 1 2013
TONIGHT...MAIN FORECAST CHALLENGE WILL BE CLOUDS AND TEMPS.
MODELS SEEM TO BE IN FAIR AGREEMENT SO WILL CONTINUE TO USE A
MODEL BLEND. NEVER SAW MUCH FOR CLOUD DEVELOPMENT TODAY SO WILL
START OFF THE NIGHT NEARLY CLOUD FREE. THERE IS AN UPSTREAM WAVE
OVER CENTRAL SASKATCHEWAN WITH SOME CLOUDS AND EVEN SOME FLURRIES
OR LIGHT SNOW ASSOCIATED WITH IT. AMERICAN MODELS HAD BEEN TRYING
TO HOLD SOME OF THIS LIGHT PCPN TOGETHER ALL THE WAY INTO THE
NORTHERN FA LATE. 12Z RUNS OF THE NAM/GFS STILL HOLD IT TOGETHER
BUT SEEM TO ERODE IT EITHER BEFORE IT GETS INTO OUR FA...WHILE
THE ECMWF REMAINS DRY. THEREFORE WILL KEEP THE FORECAST DRY
TONIGHT. AS FAR AS TEMPS GO SFC HIGH PRESSURE STILL REMAINS OVER
THE FA WITH SOME PRETTY LIGHT WINDS. WILL STICK WITH LOWS TONIGHT
FAIRLY SIMILAR TO THOSE FROM THIS MORNING.
TUE...SFC HIGH REMAINS IN CLOSE PROXIMITY TO THE RED RIVER VALLEY
KEEPING WINDS ON THE LOW SIDE AGAIN. LINGERING CLOUD COVER MAY
HAVE SOME INFLUENCE ON HIGHS FOR THE DAY. GENERALLY KEPT HIGHS
ABOUT 5F WARMER THAN TODAY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 317 PM CDT MON APR 1 2013
TUE NIGHT-THU...WED IS STILL ON TRACK TO BE THE WARMEST DAY OF THE
WEEK WITH 850MB TEMPS REACHING UP INTO THE +6C TO +8C RANGE OVER
PORTIONS OF THE FA WITH A LITTLE STEADIER SOUTH WINDS. MAYBE NOT
THE BEST DIRECTION FOR REALLY GOOD WARMING BUT AS THE COLD FRONT
COMES THRU THEY SHOULD SWITCH TO THE WEST THEN NW. STILL LOOKS
LIKE A LITTLE BIT OF PCPN WILL COME THROUGH WITH THE COLD FRONT
BUT TRIED TO NARROW DOWN THE WINDOW A BIT BETTER. SHOULD REALLY BE
A QUICK SHOT ALONG THE FRONT AND TEMPS SHOULD BE WARM ENOUGH TO
KEEP ANY PCPN IN THE LIQUID FORM UNLESS MORE PCPN LINGERS BEHIND
THE FRONT. THU WOULD BE COOLER BEHIND THE FRONT.
THU NIGHT-MON...AN ENERGETIC JET STREAM WITH SOMEWHAT FLATTENED
LONGWAVE RIDGE PATTERN IN THE LATE WEEK THEN TRANSITIONS TO A
BROAD WESTERN TROF OVER THE WEEKEND. THIS PRODUCES A BRIEF RETURN
TO NORTHWEST MID LEVEL FLOW OVER THE AREA ON THURSDAY AND A SUBTLE
/FEW DEGREE/ COOL DOWN BEHIND A SURFACE COLD FRONT. A RETURN
SOUTHERLY BLAYER FLOW IS EXPECTED ON FRIDAY... WITH ALL LONG RANGE
MODELS ANTICIPATING THE ADVANCE OF A COLORADO LOW INTO THE CENTRAL
AND NORTHERN PLAINS BY SATURDAY. A RAIN/SNOW MIX LOOKS QUITE
PROBABLE FOR MUCH OF THE AREA FROM FRIDAY EVENING INTO SATURDAY...
WITH A SOMEWHAT COOLER AND DRIER PATTERN ON SUNDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 633 PM CDT MON APR 1 2013
THERE IS A WEAK SHORTWAVE THAT WILL PASS THROUGH THE REGION
OVERNIGHT AND INCREASE CLOUD COVER. NOT SURE HOW WIDESPREAD THE
CLOUDS WILL BE...OR EXACTLY HOW LOW. JUDGING FROM UPSTREAM
SATELLITE IMAGERY AND RAP GUIDANCE...THERE WILL LIKELY BE A PERIOD
OF BKN CIGS IN THE LOW VFR RANGE (ESPECIALLY ALONG AND WEST OF THE
RED RIVER VALLEY).
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...GODON
LONG TERM...GUST
AVIATION...TG
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
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 STATE COLLEGE PA
1121 PM EDT MON APR 1 2013
.SYNOPSIS...
THE FAMILIAR WEST-NORTHWEST FLOW WILL HANG AROUND FOR A DAY OR
TWO. THIS WILL KEEP THE TEMPERATURES BELOW NORMAL. ANY SNOW
SHOWERS ARE EXPECTED TO BE LIGHT AND CONFINED MAINLY TO THE
NORTHWEST MOUNTAINS AND LAUREL HIGHLANDS. TEMPERATURES WILL BEGIN
TO MODERATE LATER IN THE WEEK. A WAVE OF LOW PRESSURE IS EXPECTED
TO PASS WELL TO THE SOUTH OF THE STATE ON FRIDAY.
&&
.NEAR TERM /UNTIL 7 AM TUESDAY MORNING/...
STILL A LITTLE BREEZY...BUT SOME DECOUPLING IS ALLOWING SPEEDS TO
DIP A FEW MPH. TEMPS A LITTLE AHEAD OF THE DIURNAL DROP-OFF CURVE
AT THIS POINT. CLOUDS SHOULD START TO FILL IN AND/OR THICKEN BACK
UP OVER THE WEST IN THE NEXT FEW HRS. BUT THE DEWPOINTS ARE REALLY
LOW...SO WILL NOT MESS WITH THE MINS WITH NO STRONG PULL ONE WAY
OR ANOTHER TO CHANGE. RUC AND HRRR ENHANCE SOME LIFT LATER TONIGHT
OFF THE LAKE - SO CHC POPS DOWN TO THE ALLEGHENY FRONT LOOK
REASONABLE...AND SOME FLURRIES ARE EVEN EXPECTED A LITTLE FARTHER
INTO THE CENTRAL MTS BY SUNRISE.
&&
.SHORT TERM /7 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
TUESDAY SHOULD BE THE COLDEST DAY OF THE WEEK WITH 850 MB TEMPS
FROM -9C TO -12C ONLY SUPPORTING HIGHS RANGING FROM AROUND 30
ACROSS THE NORTHWEST TO THE LOWER 40S SOUTHEAST. AS PREVIOUSLY
MENTIONED...BOUNDARY LAYER TRAJECTORIES SHOULD KEEP THE BEST
ORGANIZED LAKE EFFECT SNOW BANDS LIMITED TO NEAR THE PA/NY BORDER
BUT THERE SHOULD BE SOME FLURRIES OR SCATTERED SNOW SHOWERS AS FAR
SOUTH AS I-80. BRISK AND COOL NORTHWEST FLOW WILL CONTINUE WITH
SOME 25-30 MPH GUSTS LIKELY MIXING DOWN.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
NOT MUCH CHANGE FROM RECENT SHIFTS.
DRY AIR AND DOWNWARD MOTION SHOULD LIMIT LAKE EFFECT SNOW
SHOWERS TO MAINLY TO THE NW ON WED. PERHAPS INTO THE HIGHLANDS...
AS STRONG JET MAX DIGS SE ON WED.
STILL LOOKING DRY WEATHER FOR THU.
STILL LOOKING LIKE A CHC OF LIGHT RAIN ACROSS SOUTHERN PA
ON FRIDAY. NOT SEEING A LOT OF PHASING FOR A DEEP LOW...IF
LOW WAS DEEP...MAIN THING ACROSS CENTRAL PA WOULD BE MORE OF
A BREEZE LATER ON FRIDAY INTO FRIDAY NIGHT.
SAT LOOKING DRY...TEMPS CLOSE TO NORMAL.
MODELS AND HPC HAVE WEAK LOW TRACKING EASTWARD FOR THE
SECOND PART OF THE WEEKEND...JUST A CHC OF SHOWERS ON
SUNDAY...DID NOT GO AS FAST WITH TIMING AS THE GFS.
WENT WITH A DRY FCST ON MONDAY.
LOOKING MILDER FOR NEXT WEEK...STILL COULD BE WET AT TIMES...
DEPENDING WHERE FRONT STALLS OUT.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
NW FLOW CONTINUES OVERNIGHT AS A BAND PROPAGATES ACROSS THE LAKE
AND STREAMS THROUGH THE NW MTNS. VFR CONDITIONS TO PREVAIL IN
CENTRAL/EASTERN SECTIONS. AS THE BAND OF PRECIP MOVES IN
OVERNIGHT...EXPECT MVFR TO RETURN TO THE MTNS /KBFD/ AS COLD AIR
ALOFT BRINGS SCT SNOW SHOWERS INTO HIGHER TERRAIN. EXPECT MVFR
CIGS TO CREEP INTO THE HIGHER ELEVATION SITES BY 08Z TO AROUND
14Z. EXPECT GUSTY WINDS AFTER 14Z TO DISSIPATE ANY SHOWERS AND ANY
REDUCING CIGS WILL GRADUALLY DECREASE SKIES THROUGHOUT TUESDAY
MORNING...AND ALL SITES WILL BE VFR INTO TUESDAY EVENING.
OUTLOOK...
MON NIGHT-TUE...BRISK NW FLOW. SHSN WITH CIG/VSBY REDUCTIONS
LIKELY MAINLY N AND W.
WED...SCT SHSN WITH REDUCTIONS POSS N AND W...PRIMARILY VFR
ELSEWHERE.
THU...VFR.
FRI...PRIMARILY VFR...CHC RAIN SOUTHERN PA.
SAT...MAINLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...ROSS/DEVOIR
LONG TERM...MARTIN
AVIATION...DEVOIR/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1002 PM EDT MON APR 1 2013
.SYNOPSIS...
THE FAMILIAR WEST-NORTHWEST FLOW WILL HANG AROUND FOR A DAY OR
TWO. THIS WILL KEEP THE TEMPERATURES BELOW NORMAL. ANY SNOW
SHOWERS ARE EXPECTED TO BE LIGHT AND CONFINED MAINLY TO THE
NORTHWEST MOUNTAINS AND LAUREL HIGHLANDS. TEMPERATURES WILL BEGIN
TO MODERATE LATER IN THE WEEK. A WAVE OF LOW PRESSURE IS EXPECTED
TO PASS WELL TO THE SOUTH OF THE STATE ON FRIDAY.
&&
.NEAR TERM /UNTIL 7 AM TUESDAY MORNING/...
STILL A LITTLE BREEZY...BUT SOME DECOUPLING IS ALLOWING SPEEDS TO
DIP A FEW MPH. TEMPS A LITTLE AHEAD OF THE DIURNAL DROP-OFF CURVE
AT THIS POINT. CLOUDS SHOULD START TO FILL IN AND/OR THICKEN BACK
UP OVER THE WEST IN THE NEXT FEW HRS. BUT THE DEWPOINTS ARE REALLY
LOW...SO WILL NOT MESS WITH THE MINS WITH NO STRONG PULL ONE WAY
OR ANOTHER TO CHANGE. RUC AND HRRR ENHANCE SOME LIFT LATER TONIGHT
OFF THE LAKE - SO CHC POPS DOWN TO THE ALLEGHENY FRONT LOOK
REASONABLE...AND SOME FLURRIES ARE EVEN EXPECTED A LITTLE FARTHER
INTO THE CENTRAL MTS BY SUNRISE.
&&
.SHORT TERM /7 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
TUESDAY SHOULD BE THE COLDEST DAY OF THE WEEK WITH 850 MB TEMPS
FROM -9C TO -12C ONLY SUPPORTING HIGHS RANGING FROM AROUND 30
ACROSS THE NORTHWEST TO THE LOWER 40S SOUTHEAST. AS PREVIOUSLY
MENTIONED...BOUNDARY LAYER TRAJECTORIES SHOULD KEEP THE BEST
ORGANIZED LAKE EFFECT SNOW BANDS LIMITED TO NEAR THE PA/NY BORDER
BUT THERE SHOULD BE SOME FLURRIES OR SCATTERED SNOW SHOWERS AS FAR
SOUTH AS I-80. BRISK AND COOL NORTHWEST FLOW WILL CONTINUE WITH
SOME 25-30 MPH GUSTS LIKELY MIXING DOWN.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
NOT MUCH CHANGE FROM RECENT SHIFTS.
DRY AIR AND DOWNWARD MOTION SHOULD LIMIT LAKE EFFECT SNOW
SHOWERS TO MAINLY TO THE NW ON WED. PERHAPS INTO THE HIGHLANDS...
AS STRONG JET MAX DIGS SE ON WED.
STILL LOOKING DRY WEATHER FOR THU.
STILL LOOKING LIKE A CHC OF LIGHT RAIN ACROSS SOUTHERN PA
ON FRIDAY. NOT SEEING A LOT OF PHASING FOR A DEEP LOW...IF
LOW WAS DEEP...MAIN THING ACROSS CENTRAL PA WOULD BE MORE OF
A BREEZE LATER ON FRIDAY INTO FRIDAY NIGHT.
SAT LOOKING DRY...TEMPS CLOSE TO NORMAL.
MODELS AND HPC HAVE WEAK LOW TRACKING EASTWARD FOR THE
SECOND PART OF THE WEEKEND...JUST A CHC OF SHOWERS ON
SUNDAY...DID NOT GO AS FAST WITH TIMING AS THE GFS.
WENT WITH A DRY FCST ON MONDAY.
LOOKING MILDER FOR NEXT WEEK...STILL COULD BE WET AT TIMES...
DEPENDING WHERE FRONT STALLS OUT.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS TO PREVAIL IN CENTRAL/EASTERN SECTIONS...BUT THIS
EVENING MVFR WILL RETURN TO THE NW MTNS /KBFD/ AS COLD AIR ALOFT
BRINGS SCT SNOW SHOWERS INTO HIGHER TERRAIN. WINDS WILL GRADUALLY
DIMINISH THIS EVENING BY 02Z AT THE LATEST. EXPECT MVFR CIGS TO
CREEP INTO THE HIGHER ELEVATION SITES BY 08Z TO AROUND 14Z.
EXPECT GUSTY WINDS AFTER THIS WITH GRADUALLY DECREASING SKIES
THROUGHOUT TUESDAY.
OUTLOOK...
MON NIGHT-TUE...BRISK NW FLOW. SHSN WITH CIG/VSBY REDUCTIONS
LIKELY MAINLY N AND W.
WED...SCT SHSN WITH REDUCTIONS POSS N AND W...PRIMARILY VFR
ELSEWHERE.
THU...VFR.
FRI...PRIMARILY VFR...CHC RAIN SOUTHERN PA.
SAT...MAINLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...ROSS/DEVOIR
LONG TERM...MARTIN
AVIATION...DEVOIR/CERU
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 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 CORPUS CHRISTI TX
656 PM CDT MON APR 1 2013
.DISCUSSION...SEE AVIATION SECTION FOR 00Z TAFS.
&&
.AVIATION...DEEPER MOISTURE AXIS AND STRONGER INSTABILITY IS EXPECTED
TO REMAIN NEAR AND WEST OF THE RIO GRANDE FOR TONIGHT. WATER VAPOR
IMAGERY SHOWS AN UPPER LEVEL DISTURBANCE MOVING THROUGH COAHUILA TO
THE SOUTH OF THE TEXAS BIG BEND WITH SCATTERED STRONG CONVECTION MOVING
SLOWLY TO THE EAST. SOME OF THIS ACTIVITY COULD APPROACH THE RIO
GRANDE LATER THIS EVENING AFFECTING LAREDO BUT CONFIDENCE IS NOT VERY
HIGH AS LAYER OF STRATOCU LIMITED HEATING/INSTABILITY TO THE WEST OF
LAREDO THIS AFTERNOON.
BOUNDARY LAYER MOISTURE WILL STEADILY INCREASE OVER THE COASTAL PLAINS
LATER TONIGHT. ALREADY SEEING SOME PATCHY IFR CEILINGS ALONG THE COAST.
EXPECT LOWER CEILINGS/MVFR TO MOVE INLAND AND COVER MUCH OF THE COASTAL
PLAINS BY 02-03Z. THE CEILINGS WILL LOWER TO IFR BY 06Z-08Z WITH
AREAS OF FOG DEVELOPING LEADING TO MAINLY MVFR VISIBILITIES.
ADVECTION OF LOW LEVEL WARM MOIST AIR WILL LEAD TO SCATTERED
SHOWERS/ISOLATED T-STORMS OVER THE COASTAL PLAINS BY 16Z TUESDAY
AS ANOTHER UPPER LEVEL DISTURBANCE MOVES TOWARD THE AREA FROM
NORTHERN MEXICO. CEILINGS WILL LIFT TO LOW END MVFR AROUND 16Z AND
CONTINUE TO LIFT TO 2000-2500 FT BY THE AFTERNOON WITH SCATTERED
THUNDERSTORMS AFFECTING MUCH OF SOUTH TEXAS. STORMS COULD PROVIDE
IFR VSBYS IN LOCALLY HEAVIER DOWNPOURS.
&&
.PREV DISCUSSION... /ISSUED 329 PM CDT MON APR 1 2013/
SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...ANOTHER ONE OF THESE
FORECASTS WHERE MESO-SCALE INFLUENCES MAY PLAY HAVOC ON WHAT
TRANSPIRES TONIGHT. MAIN FLY IN OINTMENT NOW IS THAT LOTS OF
STRATUS IS JUST ACROSS THE RIVER AND TEMPERATURES OUT WEST ARE NOT
THAT WARM...SO SEA BREEZE LIMITED OUT THERE AS WELL AS DAYTIME
HEATING. THUS...CONVERGING BOUNDARIES LIKE LAST NIGHT NOT PRESENT
AND STORMS MAY HAVE A HARD TIME FIRING UP DIRECTLY WEST OF
FORECAST AREA. HOWEVER...STORMS ARE DEVELOPING FARTHER NORTHWEST
OF STRATUS DECK (HAVE A LONG WAY TO GO THOUGH). STILL AM GOING
TO GO WITH LOW CHANCE POPS NEAR RIO GRANDE AND DIMINISH THEM
FARTHER EAST. THING THAT HELPS CONVECTION TO DEVELOP IS EASTERLY
UPSLOPE FLOW SO DO NOT WANT TO GO TOO LOW ON POPS (ESPECIALLY WITH
SLIGHT RISK IN AREA)...AND WITH SPC 4 KM MODEL AND HRRR MODEL
SHOWING ACTIVITY MOVING IN THERE. OTHERWISE...TEMPERATURES SHOULD
BE SIMILAR TO LAST NIGHT...EXCEPT WHERE CONVECTION COULD COOL
AIR SOME. NO SIGNIFICANT FOG EXPECTED.
UPPER LEVEL JET IMPACTS AREA ON TUESDAY AS CAP BREAKS/WEAKENS. AM
GOING HIGH CHANCE POPS EASTERN AREAS...TAD LOWER OUT WEST. MORE
CLOUDS AND RAIN-COOLED AIR MEANS LOWER TEMPERATURES TUESDAY. SOME
JET DYNAMICS REMAIN TUESDAY NIGHT AS FRONT APPROACHES...SO PRETTY
MUCH HAVE KEPT POPS SIMILAR TO PREVIOUS FORECAST WITH SLIGHT
ADJUSTMENT OF HIGHER POPS A BIT MORE TOWARD THE NORTHEAST (AREA
ADJUSTEMENT...STILL NO MORE THAN 70 POPS). WITH COOLER AIR
REMAINING NORTH OF AREA (BUT PROBABLY SOME CONVECTION AROUND
COOLING THINGS OFF)...WILL GO A BIT COOLER TUESDAY NIGHT THAN
TONIGHT. SPECIAL WEATHER STATEMENT HAS BEEN ISSUED TO HIGHLIGHT
UPCOMING EVENT.
MARINE (TONIGHT THROUGH TUESDAY NIGHT)...SEA FOG ALBEIT LIGHT
REMAINS IN THE FORECAST AS VISIBLE SATELLITE AND OBSERVATIONS SHOW
SOME OUT THERE. OVERALL VISIBILITIES SHOULD REMAIN ABOVE 2 NM.
GENERALLY WEAK TO MODERATE ESE/SE FLOW THROUGH THE PERIOD. RAIN
CHANCES INCREASE MAINLY LATE TUESDAY AND TUESDAY NIGHT.
LONG TERM (WEDNESDAY THROUGH SUNDAY)...OVERALL TREND CONTINUES
ABUNDANT GULF MOISTURE ACROSS THE REGION WITH PWATS 1.3 TO 1.5
INCHES...WHICH IS JUST OVER 75 PERCENT OF NORMAL PWATS FOR THIS TIME
OF YEAR. TIMING OF THE FRONT STILL REMAINS A CHALLENGE ALTHOUGH
MODEST AGREEMENT BETWEEN THE EURO/CANADIAN/NAM AROUND 00Z...WITH THE
GFS LAGGING A FEW HOURS BEHIND. A PREFRONTAL WIND SHIFT SHOULD TAKE
PLACE BETWEEN 18Z-00Z. WITH MULTIPLE SHORTWAVES ROUNDING THE
SOUTHERN PERIPHERY OF THE MIDLEVEL LOW //POSITIONED OVER THE CENTRAL
PLAINS//...CONTINUED HIGH END CHANCE TO LIKELY POPS GOING INTO
WEDNESDAY...WITH MOST ACTIVITY IN THE MORNING BEING MORE OF A SHOWER
ACTIVITY UNDER A WEAK CAP. HOWEVER...DID CONTINUE THUNDER WORDING AS
A VORT MAX AND 60 KNOT JET MOVE OVER THE AREA. DID SHOW THE INCREASE
IN CHANCES INTO THE AFTERNOON AS FURTHER COOLING IN THE MIDLEVELS
TAKES PLACE WITH THE FRONT SLOWLY MOVING SOUTHWARD. CONCERN DOES
EXIST IN THE AFTERNOON TO EARLY EVENING FOR STRONG TO SEVERE AS
LAPSE RATES STEEPEN WITH LI VALUES OF -7C TO -9C. HOWEVER...THE
ONSHORE IS WEAK TO FEED INTO ANY STORMS. CURRENTLY IF ANYTHING
DEVELOPS INTO THE STRONG TO SEVERE CATEGORY...SHOULD BE MORE OF
PULSE STORMS...WITH BETTER CHANCES ALONG THE FRONT ITSELF. WILL
CONTINUE TO MONITOR THE DEVELOPMENT OF THIS WEATHER EVENT. MOISTURE
AND THE MIDLEVEL LOW PULLS TO THE NORTHEAST WITH DRYING FROM WEST TO
EAST LATE WEDNESDAY INTO THURSDAY WITH HIGH PRESSURE ENTERING THE
REGION. QUIET WEATHER TO PERSIST INTO THE WEEKEND WITH A ONSHORE
FLOW DEVELOPING SATURDAY. TEMPERATURES TO COOL INTO THE 70S AREAWIDE
THURSDAY...WITH A WARMING TREND INTO THE WEEKEND UNDER MOSTLY CLEAR
TO PARTLY CLOUDY SKIES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 68 82 69 81 55 / 10 50 50 70 40
VICTORIA 66 80 66 76 52 / 10 50 70 70 40
LAREDO 67 86 70 83 58 / 30 30 30 40 10
ALICE 68 86 69 83 55 / 10 50 50 60 30
ROCKPORT 68 77 68 75 55 / 10 50 60 70 40
COTULLA 65 83 67 78 53 / 30 30 50 50 10
KINGSVILLE 67 84 69 82 55 / 10 50 40 60 40
NAVY CORPUS 68 78 69 76 58 / 10 50 50 70 40
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
TMT/89...AVIATION
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
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...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 MIAMI FL
447 AM EDT TUE APR 2 2013
.DISCUSSION...
THE WEATHER FOR THE MOST PART IS QUIET. THERE IS SOME DENSE FOG IN
THE WESTERN HALF OF THE FORECAST AREA, AND SOME LOCALIZED FOG NEAR
TAMIAMI. SO, A DENSE FOG ADVISORY IS IN PLACE FOR PORTIONS OF
SOUTH FLORIDA. THIS FOG SHOULD BURN OFF WITHIN A COUPLE OF HOURS
AFTER SUNRISE.
OTHERWISE, HIGH PRESSURE IS BUILDING IN TODAY. AREAS IN THE
INTERIOR PORTIONS OF THE STATE WILL SEE HIGH TEMPERATURES IN THE
MID TO UPPER 90S. COASTAL AREAS WILL SEE HIGHS IN THE LOW TO MID
80S. THERE SHOULD BE A DECENT SEA BREEZE TO DEVELOP TODAY. WITH
SOME MOISTURE, WILL HAVE TO WATCH FOR INDICATIONS THAT SOME
SHOWERS MAY DEVELOP IN THE INTERIOR, ESPECIALLY IF THERE IS ANY
SEA BREEZE CONVERGENCE. NAM MODEL SOUNDINGS ARE SHOWING A GOOD CAP
BETWEEN 500 AND 600 MB. THE HRRR IS HINTING THAT SOMETHING MAY
DEVELOP, BUT IT IS AT THE END OF ITS MODEL RUN AND WOULD LIKE TO
SEE WHAT IT DOES WITH THIS BEFORE PUTTING ANYTHING IN THE FORECAST
FOR THIS AFTERNOON. HAVE KEPT POPS JUST BELOW SLIGHT CHC FOR THE
INTERIOR FOR NOW.
BY WEDNESDAY, A DEVELOPING LOW OVER THE WESTERN GULF OF MEXICO
WILL CAUSE THE DEVELOPMENT OF A WARM FRONT ACROSS NORTH FLORIDA.
THIS WILL ALLOW FOR A SOUTHEASTERLY FLOW, WHICH WILL HAVE SOME
LIFT. THIS COULD ALLOW SOME SHOWERS TO DEVELOP ALONG THE BORDER
WITH CENTRAL FLORIDA. HAVE KEPT SLIGHT CHANCE POPS IN FOR THAT
AREA INTO THE EVENING HOURS. SPC DOES OUTLOOK THE AREA FOR A
GENERAL THUNDERSTORM, BUT THERE IS BETTER 500MB VORTICITY
ADVECTION TO THE NORTH, OVER CENTRAL FLORIDA. SO, KEPT THUNDERSTORMS
OUT OF THE FORECAST FOR WEDNESDAY AFTERNOON WITH THIS FORECAST
ISSUANCE.
THE LOW, THAT CAUSED THE WARM FRONT, WILL QUICKLY STRENGTHEN AND
MOVE NORTHEAST OVER THE FLORIDA PANHANDLE BY FRIDAY MORNING. THE
ASSOCIATED COLD FRONT WILL MAKE ITS WAY ACROSS THE GULF AND WILL
FIRST IMPACT CENTRAL FLORIDA. MODELS ARE STILL IN PRETTY GOOD
AGREEMENT WITH THE STRENGTH, PLACEMENT, AND TIMING OF THE LOW, WITH
A FEW MINOR DISCREPANCIES. THEY SHOW THE SOUTH FLORIDA COULD SEE
SOME SHOWER ACTIVITY MOVING INTO THE AREA BY 12Z FRIDAY. THERE ARE
INDICATIONS THAT A PRE-FRONTAL TROUGH WILL MOVE ACROSS THE AREA BY
18Z AND THEN THE MAIN FRONT WILL PUSH THROUGH SOMETIME AROUND 00Z
SATURDAY. THERE IS A STRONG 500MB TROUGH/LOW, DEPENDING ON WHICH
MODEL YOU LOOK AT, ASSOCIATED WITH THIS SYSTEM. THIS WILL HELP TO
DEVELOP SOME HEAVIER SHOWERS. THE MAIN QUESTION IS THE THREAT OF
THUNDERSTORMS. CURRENTLY, IT IS DIFFICULT TO TELL HOW HIGH THE
PROBABILITY OF THUNDERSTORMS WILL BE. THE REASON IS THAT THE
ATMOSPHERE COULD GET MIXED WELL BY THE PRE-FRONTAL TROUGH AND KEEP
THE SKIES CLOUDY, REDUCING DAYTIME HEATING. THIS COULD REDUCE THE
POTENTIAL, BUT DONT THINK ELIMINATE IT. HAVE KEPT HIGH CHC POPS IN
FOR FRIDAY AND EVEN MENTION A SLIGHT CHANCE FOR TSTMS LATE
THURSDAY NIGHT. IF THE ATMOSPHERE IS NOT TOO MIXED EARLY ON, THERE
COULD BE A DECENT COVERAGE OF STORMS, AND SOME OF THOSE COULD
BECOME STRONG. BUT, IT IS STILL TOO FAR OUT TOO MAKE ANY REAL
ASSUMPTIONS. SO WILL KEEP IT SIMPLE WITH A CHC OF SHOWERS AND
TSTMS FOR NOW.
BEHIND THIS FRONT, TEMPERATURES ARE NOT GOING TO BE TOO GREATLY
AFFECTED AND HIGH PRESSURE WILL BUILD IN TO BRING QUIET WEATHER
FOR THE WEEKEND AND THE BEGINNING OF NEXT WEEK. CURRENTLY LOOKING
AT MID TO UPPER 70S FOR THE COASTAL AREAS TO LOW 80S IN THE
INTERIOR PORTIONS ON SATURDAY, WITH HIGH A FEW DEGREES HIGHER ON
SUNDAY.
&&
.MARINE...
HIGH PRESSURE WILL BUILD IN TODAY. THIS WILL KEEP THE WEATHER
QUIET OVER THE GULF AND ATLANTIC WATERS FOR TODAY THROUGH TOMORROW
MORNING. AN APPROACHING SYSTEM WILL BRING A CHANCE FOR SOME
SHOWERS TO THE AREA AS EARLY AS WEDNESDAY LATE AFTERNOON.
&&
.FIRE WEATHER...
FOG IS THE MAIN FIRE WEATHER CONCERN THIS MORNING. SOME OF THE
AREAS ARE DENSE, AND MAYBE MORE SO DUE TO THE SMOKE FROM THE
HUCKABEE FIRE IN COLLIER COUNTY. CONDITIONS SHOULD IMPROVE WITHIN A
COUPLE OF HOURS AFTER SUNRISE. HIGH PRESSURE WILL BUILD IN TODAY
AND HIGH TEMPERATURES WILL FLIRT WITH 90 DEGREES IN THE INTERIOR.
THIS WILL LIKELY ALLOW A SEA BREEZE TO DEVELOP THIS AFTERNOON.
CURRENT MODELS DO SHOW THE SEA BREEZES CONVERGING OVER THE CENTRAL
PART OF THE STATE, QUITE POSSIBLY NEAR THE HUCKABEE FIRE. THIS
COULD LEAD TO BETTER INSTABILITY IN THE VICINITY OF THE FIRE.
THERE IS ALSO A SMALL POSSIBILITY OF SOME SHOWERS DEVELOPING IN
THE AREA THEY CONVERGE, BUT TOO EARLY TO TELL.
A LOW WILL BEGIN TO DEVELOP IN THE WESTERN GULF TODAY AND A WARM
FRONT WILL SET UP OVER NORTH FLORIDA. THIS COULD ALLOW SOME
SHOWERS TO BEGIN TO DEVELOP AS FAR SOUTH AS HENDRY/INTERIOR
COLLIER COUNTIES TOMORROW AFTERNOON. A COLD FRONT IS EXPECTED TO
MOVE ACROSS THE AREA FRIDAY, BRINGING SHOWERS AND POSSIBLY
THUNDERSTORMS TO THE AREA BEGINNING EARLY FRIDAY MORNING, THROUGH
FRIDAY EVENING.
&&
.PREV DISCUSSION... /ISSUED 138 AM EDT TUE APR 2 2013/
AVIATION...
FOG WAS BEGINNING TO DEVELOP ACROSS THE INTERIOR AND TOWARDS KAPF
EARLY THIS MORNING. MVFR CONDITIONS ARE EXPECTED TO DEVELOP OVER
THE NEXT FEW HOURS THROUGH 14Z. IFR CONDITIONS COULD BRIEFLY OCCUR
AT KAPF. SEA FOG IS POSSIBLE TO THE WEST OF KAPF OVER THE GULF
TODAY AS WELL. LIGHT WINDS WILL CONTINUE OVERNIGHT. SEA BREEZE
BOUNDARIES ARE EXPECTED TO DEVELOP BY EARLY AFTERNOON AT BOTH
COASTS. WINDS WILL SLOWLY DIMINISH AFTER SUNSET TO AROUND 5 KT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 81 68 80 69 / - - 10 20
FORT LAUDERDALE 82 71 81 71 / - - 10 0
MIAMI 83 70 81 70 / - - 10 0
NAPLES 80 64 81 66 / - - 10 -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR GLADES-HENDRY-
INLAND BROWARD-INLAND COLLIER-INLAND MIAMI DADE-INLAND PALM
BEACH.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...13/SI
AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION...UPDATE
NWS PEACHTREE CITY GA
140 AM EDT TUE APR 2 2013
.UPDATE...
TWO WEAK BOUNDARIES ACROSS THE CWFA THIS EVENING...BOTH WEAK COLD
FRONTS. THE FIRST FRONT IS ACROSS NORTHERN GA AND THE SECOND IS
ACROSS THE SOUTHERN CWFA. NO REAL MOISTURE ASSOCIATED WITH EITHER
OF THESE FEATURES OTHER THAN SOME CU...SO HAVE REMOVED THE MENTION
OF POPS. ANY SCT CU SHOULD ALSO DISSIPATE WITH SUNSET.
TWEAKED HOURLY TEMPS A BIT...THEY WERE NOT FALLING OFF AS FAST AS
FORECAST. ADJUSTED THE MIN TEMPS A FEW HOURS...WITH THE METRO AREA
A COUPLE OF DEGREES WARMER.
&&
.PREV DISCUSSION... /ISSUED 350 PM EDT MON APR 1 2013/
..BRIEF DRY PERIOD BEFORE RAIN RETURNS MID WEEK...
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
LATEST SURFACE ANALYSIS SHOWS SEMI PERMANENT SURFACE TROUGH FROM
JUST SOUTH OF ATHENS THROUGH COLUMBUS. ALONG AND SOUTH OF THIS
FEATURE MOISTURE SURFACE CONVERGENCE HAS RESULTED IN SCATTERED TO
BROKEN CU DEVELOPMENT BUT SHOWER ACTIVITY HAS REMAINED OUTSIDE OF
THE FORECAST AREA. FURTHER NORTH...SURFACE FRONT CONTINUES TO SAG
INTO NORTH GA WITH MOISTURE POOLING ALONG ITS LEADING EDGE AS WELL
AND ADDITIONAL CLOUD DEVELOPMENT THE RESULT.
THIS SHOULD REMAIN JUST CLOUDS WITH NO PRECIP FOR THIS EVENING AS
MAIN FOCUS WILL BE ON SOUTHERN TROUGH AND IT AFFECTS ON CENTRAL
GEORGIA. LOOKING AT THE LATEST RAP ANALYSIS OF CAPE IN THIS
VICINITY AND WE SEE 500 J/KG TO 1000 J/KG OF AVAILABLE
ENERGY...SLIGHTLY HIGHER THAN MODEL PROJECTIONS. STILL LOOKING AT
500MN TEMPS IN THE VERY COLD RANGE OF -17C IN THIS AREA SO ANY
SUSTAINED UPDRAFTS WILL BE CAPABLE OF PRODUCING LARGE HAIL.
ACTIVITY WILL SHIFT EAST QUICKLY THIS EVENING WITH CLEARING
CONDITIONS TAKING PLACE. STILL SOME GRADIENT IN PLACE ACROSS THE
AREA WHICH WILL PREVENT OPTIMUM RADIATIONAL COOLING CONDITIONS.
WENT WITH A MAV/MET BLEND FOR THE OVERNIGHT TEMPS WHICH WILL BE
TRICKY TO THE SOUTH BASED ON HOW FAST CLOUDS CLEAR.
SURFACE FRONT LOOKS TO STALL ACROSS NORTH GEORGIA TUESDAY AND
IMPULSES OF ENERGY BEGIN TO ROUND PERIPHERY OF EAST COAST TROUGH.
THIS SHOULD ALLOW A FEW LIGHT SHOWERS TO DEVELOP ACROSS EXTREME
NORTH GEORGIA AND HAVE INCLUDED IN THIS GRID PACKAGE. AS HIGH
BRIDGES ACROSS THROUGH TUESDAY NIGHT...MAY SEE FRONT SAG FURTHER
SOUTH AND TAKE 20 POPS ALONG WITH IT INTO THE REMAINDER OF NORTH
GEORGIA.
DEESE
LONG TERM /WEDNESDAY THROUGH MONDAY/...
MAIN CONCERN FOR THE EXTENDED REMAINS THE SYSTEM MOVING THROUGH
THE STATE ON WEDNESDAY INTO THE END OF THE WORK WEEK.
DISCREPANCIES STILL REMAIN BETWEEN THE EURO AND GFS AS FAR AS
TIMING OF THE SYSTEM LEAVING THE CWA. THE 12Z MODELS ARE
STRIKINGLY SIMILAR TO THEIR 00Z COUNTERPARTS. AS SUCH...WAS NOT
ABLE TO NAIL DOWN AN ACCURATE END TO THE RAIN THIS WEEK. ACCORDING
TO HPC MODEL DISCUSSIONS THE EURO IS AN OUTLIER...MOVING THE
SYSTEM FURTHER SOUTH AND IS SLOWER. THAT SAID THEY DECIDED TO WITH
A BLEND BETWEEN THE 00Z EURO AND THE 06Z GEFS. WITH THIS MUCH
UNCERTAINTY DECIDED TO ONLY CHANGE THE COVERAGE OF THUNDER ON
WEDNESDAY AND LEAVE THE REST OF THE FORECAST ALONE. DID LOWER
TEMPS ON THURSDAY AS A PSEUDO WEDGE BUILDS IN. CLOUDS AND RAIN IN
ASSOCIATION WITH THIS WEDGE SHOULD HELP TO KEEP TEMPS LOW. HAVE
INCLUDED PREVIOUS EXTENDED BELOW/
ARG
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... POTENTIAL FOR A HEAVY
RAIN/SEVERE WEATHER EVENT SETTING UP IN THE THURSDAY TO THURSDAY
NIGHT TIME FRAME. MODELS SIMILAR WITH SPREADING DEEPER MOISTURE
INTO THE AREA LATE WEDNESDAY BUT THE MAIN PRECIP PERIOD LOOKS TO
BE WEDNESDAY NIGHT THRU THURSDAY NIGHT. AN OVERRUNNING PATTERN
WILL SET LATE WEDNESDAY/WEDNESDAY NIGHT WITH MODELS DEVELOPING A
WARM FRONT ALONG THE GULF COAST. SURFACE LOW PRESSURE DEVELOPS
OVER THE WESTERN GULF AND MOVES TO THE WESTERN FL PANHANDLE LATE
THURSDAY AND THEN ACROSS CENTRAL TO S GA THURSDAY NIGHT/FRIDAY.
THE GFS IS FASTER WITH THIS PROGRESSION THAN THE EUROPEAN. THIS
TRACK COULD MOVE THE WARM FRONT INTO THE SE CWA AND GIVE POTENTIAL
FOR SEVERE THUNDERSTORMS MAINLY THURSDAY NIGHT. IT WILL ALSO GIVE
POTENTIAL FOR HEAVY RAIN ACROSS A LARGE PORTION OF EAST GEORGIA
AND MODELS IN GENERAL ARE LESS GUN-OH WITH PRECIP AMOUNTS WITH A
LARGE AREA OF 1-2 INCHES FORECAST. THE UPPER TROUGH MOVES ACROSS
THE AREA ON FRIDAY AND THE GFS IS FASTER WITH THIS PROGRESSION
THAN THE EUROPEAN. THE AIRMASS DRIES OUT FOR SATURDAY AND MOSTLY
LIKELY SUNDAY WITH THE EUROPEAN INDICATING SOME MOISTURE
ASSOCIATED WITH A SHORT WAVE ON SUNDAY...MOST SO FOR N GA. FOR NOW
WILL KEEP THINGS DRY AND MONITOR THE PROGRESSION. A SHORT WAVE
RIDGE BUILDS FOR MONDAY WITH THE EUROPEAN CONTINUING TO SHOW MORE
MOISTURE SKIRTING OVER N GA THAN THE GFS.
BDL
AVIATION...
06Z UPDATE...
VFR THROUGH THE FORECAST PERIOD. SOME SCT050-060 POSSIBLE DURING THE
AFTERNOON. LIGHT NORTHWEST WINDS WILL CONTINUE UNTIL AROUND 12Z THEN
A BRIEF PERIOD OF NORTH FLOW IS POSSIBLE DURING THE MORNING BUT
PREDOMINATELY NORTHWEST DURING THE AFTERNOON.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM ON WIND SHIFT.
HIGH ON REMAINING ELEMENTS.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 42 69 41 64 / 10 10 20 20
ATLANTA 47 67 44 64 / 5 5 20 20
BLAIRSVILLE 37 58 35 63 / 10 10 20 20
CARTERSVILLE 41 65 40 64 / 5 10 20 20
COLUMBUS 51 75 50 70 / 5 5 5 30
GAINESVILLE 44 65 43 61 / 10 10 20 20
MACON 45 75 44 69 / 5 5 5 30
ROME 38 65 38 64 / 5 10 20 20
PEACHTREE CITY 40 70 42 65 / 5 5 20 30
VIDALIA 55 76 51 74 / 20 0 5 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
524 AM EDT TUE APR 2 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EDT TUE APR 2 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF OVER
THE E HALF OF NAMERICA DOWNSTREAM OF RDG OVER WRN CANADA. CWA
REMAINS DOMINATED BY COLD CYC NW FLOW IN THE WAKE OF SLOWLY
DEPARTING CLOSED LO OVER WRN QUEBEC. ALTHOUGH H85 TEMPS RANGING FM
-14C OVER THE W TO -16C OVER THE E AND INVRN BASE NEAR H8 ARE
SUFFICIENTLY COLD/HI FOR LES EVEN IN THE ABSENCE OF ANY DYNAMIC
FORCING...UPSTREAM 00Z INL/YPL RAOBS ARE SO DRY...WITH THE H925
DEWPT DEPRESSION 15C AT INL IN INVERTED V T/TD PROFILE...THAT THERE
ONLY A FEW WEAK CLD BANDS OVER THE W HALF OF LK SUP STREAMING INTO
THE WRN ZNS. WITH A LONGER FETCH OVER THE E HALF AND A WEAK SFC TROF
PASSING THRU THIS AREA...MORE CLDS/SOME LES BANDS ARE EVIDENT
STREAMING INTO THE CWA E OF MQT. BUT DRYNESS OF AIRMASS IS EVIDENT
IN LO REFLECTIVITIES. LOOKING FARTHER UPSTREAM...THERE IS A FAIRLY
VIGOROUS SHRTWV NEAR LK WINNIPEG DIGGING SEWD. BUT SINCE THE 00Z THE
PAS MANITOBA RAOB IS ALSO QUITE DRY WITH INVERTED V T/TD PROFILE IN
THE LLVLS...THERE ARE ONLY SOME PATCHY MID/HI CLDS IN THE PVA
ASSOCIATED WITH THIS FEATURE. ANOTHER SHRTWV OVER HUDSON BAY IS
DIVING SWD.
EARLY THIS MRNG/TODAY...WITH NOCTURNAL COOLING EARLY THIS MRNG AND
SOME ENHANCED LLVL CNVGC ALONG WEAK SFC TROF...EXPECT SCT-NMRS -SHSN
TO IMPACT THE ERN ZNS THRU THIS MRNG. OVER THE W...THERE SHOULD BE
LTL IF ANY LES OR EVEN LK CLDS THRU 09Z GIVEN THE UPSTREAM
DRYNESS...BUT MODELS SHOW AREA OF DPVA/H85-5 QVECTOR CNVGC
ASSOCIATED WITH SHRTWV DIGGING THRU MN IMPACTING THE FAR W BY 12Z.
SUSPECT MORE CLDS/A FEW -SHSN MIGHT DVLP IN PRESENCE OF NOCTURNAL
COOLING...BUT LLVL DRYNESS WL LIMIT COVERAGE/INTENSITY OF ANY SHSN
THAT MIGHT POP UP. IF THERE IS ANY SHSN...THESE SHOULD DIMINISH ONCE
THE FORCING PASSES TO THE S BY 15Z AND DAYTIME HEATING BEGINS TO
DISRUPT THE LES PROCESS. LATE IN THE DAY...NEXT SHRTWV OVER HUDSON
BAY IS PROGGED TO DIG INTO THE UPR LKS WITH ACCOMPANYING DPVA AND
H85-5 QVECTOR CNVGC IMPACTING THE CWA. ALTHOUGH DAYTIME HEATING
MIGHT ALSO DISRUPT THE LES OVER THE E HALF IN THE AFTN...THE ARRIVAL
OF THIS FORCING MIGHT CAUSE AN UPTICK OF SHSN AGAIN TOWARD 00Z
ESPECIALLY OVER THE E HALF CLOSER TO DEEPER MSTR/COLDER AIR.
AS FOR TEMPS...PREFER TO TEND TOWARD THE HIER END OF GUIDANCE WITH A
GOOD DEAL OF SUNSHINE...AT LEAST OVER THE W AND SCENTRAL.
TNGT...SHRTWV DROPPING S INTO THE UPR LKS AND ACCOMPANYING DYNAMIC
FORCING IS PROGGED TO CROSS THE ERN COUNTIES. WITH LOWER H85 TEMPS
ARND -17C CLOSER TO THE CYC SIDE OF THE TRACK OF THIS DISTURBANCE AS
WELL AS DEEPER MSTR/SOMEWHAT HIER INVRN SHOWN THERE ON FCST SDNGS...
OPTED TO RAISE POPS INTO THE LIKELY RANGE NEAR LK SUP E OF MQT AS
THESE EVENTS OCCUR DURING THE MORE FAVORABLE NOCTURNAL COOLING.
EXPECT MUCH LESS IF ANY ACTIVITY OVER THE W ON THE ACYC SIDE OF THE
SHRTWV PASSAGE AND WHERE FCST SNDGS SHOW MUCH DRIER AIR AND HIER H85
TEMPS/LOWER INVNR BASE. EXPECT THE LOWEST MIN TEMPS TOWARD THE LOWER
END OF GUIDANCE OVER THE INTERIOR W UNDER THE DRIER AIR AND WHERE
WINDS WL BE LIGHTER.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 520 AM EDT TUE APR 2 2013
LOOKS LIKE A PATTERN CHANGE IS IN THE OFFING OVER THE NEXT FEW WEEKS
THAT WILL TRANSITION THE PERSISTENT BELOW NORMAL TEMP REGIME TOWARD
AN ABOVE NORMAL ONE. THE AO AND NAO WHICH HAVE BEEN IN A PREVAILING
NEGATIVE PHASE SINCE EARLY/MID FEB ARE BOTH FORECAST TO TREND TO THE
POSITIVE PHASE...WITH THE AO BECOMING STRONGLY POSITIVE. THIS
SUPPORTS A TREND TOWARD ABOVE NORMAL TEMPS HEADING INTO MID/LATE
APRIL...BUT THIS DOESN`T PRECLUDE THE POTENTIAL FOR MORE WINTRY PCPN
EVENTS BEFORE THE WARMER PATTERN SETS IN. THE PATTERN ALSO APPEARS
TO BE SHIFTING TOWARD AN ACTIVE ONE OVER THE NEXT 2 WEEKS. INTO THE
UPCOMING WEEKEND...FLOW WILL TREND PROGRESSIVE AND FLATTER WITH A
COUPLE OF SHORTWAVES TO AFFECT THE UPPER LAKES...THE FIRST WED
NIGHT/THU AND A SECOND MORE IMPORTANT WAVE SAT. EARLY NEXT WEEK...AN
AMPLIFIED TROF WILL BE DEVELOPING OVER THE WRN CONUS...SIGNALING THE
POTENTIAL FOR MORE SIGNIFICANT PCPN EVENTS NEXT WEEK FROM THE
CNTRL/SRN PLAINS TO THE GREAT LAKES AS THE GULF OPENS UP. THIS COULD
MEAN ONE OR MORE UNWELCOMED RAIN EVENTS ON A MELTING SNOWPACK WHICH
IS STILL DEEP IN THE LAKE EFFECT AREAS OR MORE SNOW COULD STILL BE
ADDED. IN RECENT DAYS...MEDIUM RANGE GUIDANCE HAS TONED DOWN THE
WARMING NEXT WEEK...SO MORE SNOW IS STILL A REAL POSSIBILITY.
BEGINNING WED...SFC HIGH PRES WILL QUICKLY SHIFT ACROSS THE WRN
GREAT LAKES AHEAD OF THE FIRST SHORTWAVE THAT WILL BE TRACKING
ACROSS SASKATCHEWAN/MANITOBA. IF ANY LIGHT LES IS LINGERING OVER THE
ERN FCST AREA TO START THE DAY...IT WILL END QUICKLY IN THE MORNING.
AFTER A PERIOD OF SUNSHINE...HIGH CLOUDS WILL BE ON THE INCREASE.
SUNSHINE WILL SUPPORT A STRONG DIURNAL TEMP SPREAD. AFTER MORNING
LOWS IN THE SINGLE DIGITS OVER THE INTERIOR W...TEMPS SHOULD REBOUND
INTO THE UPPER 30S/LWR 40S.
SHORTWAVE WILL MOVE ACROSS NRN ONTARIO WED NIGHT/THU MORNING. WITH
STRONG DEEP LAYER FORCING/IMPRESSIVE 500MB HEIGHT FALLS (AROUND
200M/12HR) PASSING WELL TO THE N OF HERE...MAIN PCPN AREA WILL PASS
TO THE N OF UPPER MI. NONETHELESS...50-80M HEIGHT FALLS AT 500MB...
RIBBON OF MODEST DEEP LAYER FORCING PER QVECTORS AND ISENTROPIC
ASCENT SUGGEST SOME PCPN POTENTIAL ACROSS THE FCST AREA. WITH
ISENTROPIC ASCENT WEAKENING AS IT SHIFTS ACROSS THE UPPER LAKES...
AND LOW-LEVEL DRY AIR TO OVERCOME INITIALLY...NOTHING MORE THAN LOW
CHC POPS APPEAR WARRANTED ATTM. ALTHOUGH LOW-LEVEL TEMPS ARE JUST
ABOVE 0C PRIOR TO POTENTIAL PCPN ARRIVING...EVAPORATIVE COOLING
SHOULD BE SUFFICIENT SO THAT SNOW BECOMES THE MAIN PTYPE IN MOST
AREAS. PCPN CHC WILL END W TO E THU MORNING WITH DRY WEATHER
FOLLOWING THRU THU NIGHT/FRI AS SFC HIGH PRES RIDGE BUILDS SE INTO
THE UPPER LAKES. 850MB TEMPS FALLING TO AROUND -12C THU NIGHT/FRI
MORNING WILL BE AT THE THRESHOLD FOR LES. HOWEVER...SINCE LOW-LEVEL
FLOW BECOMES MORE ANTICYCLONIC DURING THE NIGHT AND AIR MASS IS
FAIRLY DRY IN THE LOW-LEVELS...WILL NOT INCLUDE ANY MENTION OF
-SHSN. OVER THE W...FLOW IS MORE DIVERGENT...SO THERE MAY NOT EVEN
BE MUCH IN THE WAY OF CLOUDS. OPTED TO GO BLO GUIDANCE THERE THU
NIGHT AS WINDS WILL PROBABLY FALL OFF TO CALM AS HIGH PRES RIDGE
NEARS. ALTHOUGH LOWERED MINS TO THE LOW/MID TEENS...TEMPS COULD
EASILY FALL INTO THE SINGLE DIGITS.
FRI NIGHT/SAT...ATTENTION TURNS TO THE SECOND MORE IMPORTANT
SHORTWAVE TRACKING ACROSS THE NRN CONUS IN FLATTER FLOW REGIME.
MEDIUM RANGE GUIDANCE IS MOVING TOWARD SLIGHTLY BETTER AGREEMENT
WITH SYSTEM...BUT IMPORTANT DETAILS HAVE YET TO BE NARROWED DOWN.
THE GFS WHICH HAS BEEN CONSISTENTLY FARTHER S HAS TRENDED A LITTLE
FARTHER N WITH WAVE AND IS IN DECENT AGREEMENT WITH THE GLOBAL GEM.
THE ECMWF HAS BEEN CONSISTENTLY FARTHER N. THE GFS TRACK LOOKS TO
SUPPORT ALL SNOW FOR THE FCST AREA AS THE 850MB LOW TRACKS ALONG
WI/UPPER MI BORDER AND 850MB TEMPS REMAIN BLO 0C AND 1000-850MB
THICKNESS IS NO HIGHER THAN 1295M. THE GLOBAL GEM MOSTLY SUPPORTS
ALL SNOW WITH A POSSIBLE CHANGEOVER TO RAIN S AND SE...BUT ITS
SLOWER/MORE WRAPPED UP SYSTEM DOES NOT APPEAR TO FIT THE DEVELOPING
FLATTER FLOW REGIME. HOWEVER...THE 00Z ECMWF ALSO TRENDED MUCH
SLOWER AND SHARPER WITH SHORTWAVE...SO THIS MAY BE AN IMPORTANT
TREND TO MONITOR IN FUTURE MODEL RUNS. THE FARTHER N ECMWF SUGGESTS
MORE OF A MIXED PCPN EVENT WITH MORE SNOW THAN RAIN N AND MORE RAIN
THAN SNOW S. THE HEAVIEST SWATH OF PCPN PASSES ACROSS NRN UPPER MI
IN THE ECMWF...JUST S IN THE GFS AND CLIPS THE SRN FCST AREA IN THE
GLOBAL GEM. WHILE THE DETAILS OF SHORTWAVE TRACK...RESULTING PCPN
AREA AND THE ALL IMPORTANT TEMP PROFILE HAVE YET TO BE AGREED
UPON...WHAT IS A LITTLE MORE CERTAIN IS THAT THIS WAVE MAY BE A
RATHER IMPRESSIVE PCPN PRODUCER DESPITE THE FLATTER FLOW REGIME.
STRONG WAA IS NOTED BY ALL GUIDANCE WITH 850MB WINDS AROUND 50KT.
THE FRONTOGENESIS SIGNAL IS ALSO QUITE STRONG. PROXIMITY OF STEEP
MIDLEVEL LAPSE RATES NEAR THE SRN EDGE OF THE PCPN AREA SUGGESTS
THERE WILL PROBABLY BE SOME CONVECTION AS IS OFTEN SEEN WITH WAVES
RUNNING ALONG THE BAROCLINIC ZONE AT THIS TIME OF YEAR. IT WILL BE A
SYSTEM TO WATCH.
IN THE WAKE OF THE SAT SYSTEM...DRY WEATHER SHOULD FOLLOW FOR SUN
UNDER WEAK SFC HIGH PRES RIDGE...THOUGH IF THE SLOWER GLOBAL GEM AND
ECMWF ARE RIGHT...SOME PCPN COULD LINGER THRU AT LEAST PART OF SUN.
ATTENTION THEN TURNS TO THE SW FOR MON/TUE AS TROF AMPLIFIES INTO
THE WRN CONUS. AMPLIFYING TROF MAY SEND SEVERAL SHORTWAVES INTO THE
GREAT LAKES NEXT WEEK WITH THE FIRST PERHAPS AS SOON AS MON. AS
WOULD BE EXPECTED WITH A DEEPENING WRN TROF...MODELS ARE AND WILL
CONTINUE TO HAVE TROUBLE WITH TIMING AND PLACEMENT OF SHORTWAVES
EJECTING NE...SO THERE IS LITTLE CONFIDENCE RIGHT NOW IN THE PCPN
FCST MON/TUE. WITH GULF OPENING UP AHEAD OF THE LARGE SCALE WRN
TROF...ANY SHORTWAVES AFFECTING THE AREA COULD BE MDT/HVY PCPN
PRODUCERS NEXT WEEK...AND PCPN COULD BE SNOW FOR PORTIONS OF UPPER
MI.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 812 PM EDT MON APR 1 2013
DRY AIR MOVING ACROSS LAKE SUPERIOR SHOULD HELP KEEP TAF SITES
MOSTLY CLEAR THROUGH THE EVENING HRS. A DISTURBANCE MOVING DOWN FM
CANADA COULD HELP GENERATE SOME LAKE CLOUDS AND FLURRIES LATE
TONIGHT INTO TUESDAY...ESPECIALLY AS WINDS OVER THE LAKE VEER NNW
ALLOWING FOR INCREASED LOW-LVL CONVERGENCE. EXPECT CIGS TO LOWER TO
MVFR AS ALL TAF SITES WITH SOME LIGHT -SHSN/FLURRIES. INCREASINGLY
ANTICYCLONIC AND DIFLUENT LOW-LVL FLOW BY 18Z TUE SHOULD ALLOW FOR
MVFR CLOUDS TO ERODE AND VFR CONDITIONS TO RETURN.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 520 AM EDT TUE APR 2 2013
WHERE THE PRES GRADIENT WILL BE SHARPER CLOSER TO DEPARTING LO PRES
IN SE CANADA...EXPECT NNW WINDS UP TO 30 KTS THRU TONIGHT OVER THE E
ALONG WITH FREEZING SPRAY. LIGHTER WINDS UP TO 20 KTS WILL PREVAIL
OVER THE W WHERE THE GRADIENT WILL BE WEAKER. AFTER A BRIEF PERIOD
OF LIGHT WINDS FOR A PORTION OF WED AS HIGH PRES QUICKLY PASSES...S
TO SW WINDS WILL QUICKLY RAMP UP TO 20-30KT WED AFTN/EVENING AHEAD OF
LOW PRES TRACKING E INTO NRN ONTARIO. ALTHOUGH LOW-LEVEL TEMP PROFILE
IS STABLE...HEALTHLY PRES FALLS PASSING ACROSS NRN ONTARIO SUGGEST
THERE WILL BE SOME POTENTIAL FOR A SHORT PERIOD OF GALES WED NIGHT.
WINDS SHIFT WNW FOR THU. WHILE WINDS WILL DIMINISH TO 15-25KT OVER
THE W...20-30KT WINDS WILL CONTINUE OVER THE E. WINDS WILL THEN
DIMINISH TO LIGHT (UNDER 15KT) FRI HAS HIGH PRES RIDGE ARRIVES. WINDS
SHOULD REMAIN UNDER 20KT SAT...BUT WITH UNCERTAINTY IN THE
STRENGTH/TRACK OF NEXT LOW PRES TRACKING E INTO THE GREAT LAKES...
WINDS COULD END UP STRONGER THAN CURRENTLY FCST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...ROLFSON
AVIATION...VOSS
MARINE...KC/ROLFSON
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
316 AM CDT TUE APR 2 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 316 AM CDT TUE APR 2 2013
TODAY...THE HIGH PLAINS DISTURBANCE OPERATING ON LIMITED
MOISTURE WILL DRIFT VERY SLOWLY EAST SOUTHEAST TODAY AND TONIGHT.
GIVEN THE DRY AIR AT THE LOWER LEVELS...SPRINKLES LOOKED REASONABLE
ACROSS SWRN NEB. MID LEVEL CLOUDINESS WILL HANG ON TODAY AND TONIGHT
ACROSS THE SOUTHWEST. ELSEWHERE...MOSTLY CLEAR. A WEAK AREA FOR
FRONTOGENESIS HAS DEVELOPED ACROSS THE MISSOURI BASIN. THE RAP MODEL
IS LIFTING THIS FEATURE UP INTO THE MIDWEST TODAY.
OTHERWISE...A WARM FRONT SHOULD LIFT NORTH INTO THE SANDHILLS TODAY
WHILE WINDS NORTH OF THE FRONT BACK TO THE EAST AND NORTHEAST. FULL
SUN IN MANY AREAS SHOULD SEND HIGHS TO AROUND 60. THE RAP SUGGESTED
LOWER 60S IN MANY AREAS BUT THAT MODEL TENDS TO RUN WARM. RH DROPS
TO 20 TO 25 PERCENT THIS AFTERNOON BUT WINDS SHOULD REMAIN BELOW 15
MPH WITH WEAK WINDS CARRYING ALL THE WAY TO 700 MB.
TONIGHT...LOW PRESSURE DEVELOPS ACROSS THE NRN HIGH PLAINS WHICH
SETS UP A STRONGER SOUTHWEST WIND TONIGHT. THIS WILL HOLD LOWS
AROUND FREEZING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 316 AM CDT TUE APR 2 2013
12Z WEDNESDAY AND BEYOND. MAIN FORECAST CONCERN GOING
IN THE EXTENDED PERIOD REVOLVES AROUND THE DEVELOPMENT OF AN
AMPLIFIED WESTERN CONUS TROUGH...WHICH MAY BRING PERIODS OF
WIDESPREAD PRECIPITATION BACK ACROSS THE CWA THIS WEEKEND AND
ESPECIALLY EARLY NEXT WEEK. BUT FIRST...AN UPPER LOW AND ATTENDANT
TROUGH THAT WILL BE POSITIONED ACROSS SOUTHEAST COLORADO/NORTHERN
NEW MEXICO EARLY WEDNESDAY WILL PROGRESS SOUTHEAST ACROSS TEXAS AND
THE SOUTHERN PLAINS THROUGH THURSDAY. THIS WILL ALLOW A TRANSITION
FROM SPLIT FLOW ALOFT OVER THE CENTRAL PLAINS...TO NORTHWESTERLY...AND
EVENTUALLY SOUTHWESTERLY AS A UPPER RIDGE BUILDS ACROSS THE PLAINS
ON FRIDAY. AT THE SAME TIME...AN UPPER TROUGH AND ATTENDANT LOW
WILL BE RAPIDLY PROGRESSING ACROSS THE CANADIAN ROCKIES TOWARD
SOUTHERN ONTARIO...DRAGGING A COLD FRONT THROUGH THE
NORTHERN/CENTRAL HIGH PLAINS EARLY ON THURSDAY. TEMPERATURES ON
WEDNESDAY WILL BE ATYPICAL...WITH THE WARMEST READINGS ACROSS
NORTHERN NEBRASKA...WHERE HIGHS IN THE LOW TO MID 60S SHOULD
PREVAIL. FOR SOUTHERN NEBRASKA...HIGHS ON WEDNESDAY WILL BE SOME
5-8F COOLER AS THE INFLUENCE OF THE SOUTHERN PLAINS UPPER LOW SHOULD
ALLOW FOR AN INCREASE CLOUDINESS AND SLIGHTLY COOLER TEMPERATURES
ALOFT. SLIGHTLY COOLER ACROSS THE NORTH ON THURSDAY AS MODIFIED
ARCTIC HIGH PRESSURE RECYCLES SOME COOLER AIR BACK INTO NORTH
CENTRAL NEBRASKA...ANTICIPATING HIGHS MAINLY IN THE MID 50S.
TEMPERATURES ACROSS THE SOUTH AND WEST WILL WARM SEVERAL DEGREES
UNDER FULL SUN AND WEAK WARMING ALOFT...MID 60S SHOULD PREVAIL.
FRIDAY WILL BE THE WARMEST DAY OF THE WEAK FOR ALL AREAS AS THE
UPPER RIDGE AXIS SHIFTS EAST ACROSS THE CWA. THERE MAY BE FIRE
CONCERNS AS SURFACE T/TDS SPREADS APPROACH 40F. SOUTHERLY WIND
SPEEDS LOOK TO INCREASE AS WELL AS A SURFACE TROUGH OF LOW PRESSURE
DEEPENS ACROSS THE HIGH PLAINS. BY EARLY SATURDAY...A WAVE WILL BE
PASSING THROUGH THE NORTHERN PLAINS WITHIN NEAR ZONAL FLOW
ALOFT...HOWEVER THE FORECAST MODELS SEEM TO BE KEYING ON MOST OF THE
QPF REMOVED FROM THE CWA...THUS WILL MAINTAIN THE INHERITED SLIGHT
CHANCE POPS FOR NOW AND NOT VENTURE ANY HIGHER. FOR SUNDAY AND
EARLY NEXT WEEK...THE LONG RANGE SOLUTIONS ALL ARRIVE AT A
SIGNIFICANT TROUGH ACROSS THE WESTERN CONUS...WITH THE POSSIBILITY
OF SEVERAL WAVES IMPACTING THE CWA...FIRST OF WHICH ARRIVES ON
SUNDAY. DIFFERENCES BETWEEN THE GFS AND EC ARE EVIDENT...MAINLY
WITH THE TIMING AND EVOLUTION OF THE MEAN WESTERN CONUS TROUGH...BUT
BOTH POINT TO A POTENTIALLY ACTIVE LATE WEEKEND/EARLY WORK WEEK SET
UP. BOTH ALSO INDICATE THE POTENTIAL OF A MYRIAD OF
PRECIPITATION...STARTING WITH TSTMS...SHOWERS...RAIN AND POSSIBLY
SNOW. WITH THE POTENTIAL SYSTEM STILL WAY OUT...DIDN/T WANT TO GET
TOO CUTE WITH PTYPE AND/OR LOCATIONS OF THE HIGHEST POPS. GENERALLY
BROAD-BRUSHED 30-40% POPS SUNDAY AND MONDAY...WITH SHOWERS POSSIBLY
CHANGING TO SNOW ACROSS THE NORTH LATE ON MONDAY...AND ACROSS THE
ENTIRE CWA EARLY TUESDAY MORNING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1241 AM CDT TUE APR 2 2013
UNLIMITED CEILING AND VISIBILITY CAN BE EXPECTED TONIGHT THROUGH
LATE TUESDAY EVENING IN CENTRAL AND WESTERN NEBRASKA. EVEN WITH
LIGHT EAST TO SOUTHEAST WIND...MOISTURE IS CONFINED TO VERY NEAR THE
SURFACE...AS CAN BE SEEN IN THE LBF SOUNDING...AND IS NOT LIKELY TO
HAVE ENOUGH DEPTH FOR THE FORMATION OF FOG.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
325 AM CDT TUE APR 2 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 324 AM CDT TUE APR 2 2013
FORECAST CHALLENGE CONCERNS MAINLY CLOUD TRENDS AND TEMPERATURES.
MODELS CLOSE IN THE SHORT TERM AND WILL BLEND. WEAK SHORT WAVE TO
DROP THROUGH MID LEVEL NORTHERLY FLOW TODAY. SATELLITE IMAGERY
INDICATING MOST ORGANIZED CLOUD COVER WITH WAVE TO DROP THROUGH
WESTERN/CENTRAL ND. WITH SURFACE HIGH PRESSURE IN PLACE WILL
MAINTAIN DRY FORECAST. WILL SEE SOME CLOUD COVER MAINLY FIRST HALF
OF THE DAY THEN MORE SOLAR. COLUMN DOES WARM A TAD BUT WITH EARLY
CLOUDS FEEL TEMPERATURES WILL TURN OUT FAIRLY CLOSE TO YESTERDAY.
AS SURFACE HIGH SHIFTS EAST TONIGHT WILL SEE INCREASED MIXING AND
WARM ADVECTION. THIS WILL HOLD TEMPERATURES UP WITH COOLEST AREAS
ACROSS THE FAR EAST WHICH WILL BE THE LAST AREA TO SEE ABOVE
CONDITIONS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 324 AM CDT TUE APR 2 2013
NEXT COLD FRONT TO DROP THROUGH FA WEDNESDAY. BASED ON TIMING OF
BOUNDARY AT THIS POINT APPEARS THAT WHAT PCPN DOES OCCUR SHOULD
INITIALLY BE LT RAIN WITH SOME PHASE ISSUES POSSIBLE DURING THE
EVENING ACROSS THE NORTHERN FA. MODELS SHOWING DIFFERENCES ON
THERMAL FIELDS AND PCPN POTENTIAL SO DID NOT MAKE ANY SIGNIFICANT
CHANGES. LOOKS TO BE THE WARMEST DAY OF THE WEEK WITH CLOUD TRENDS
INFLUENCING JUST HOW WARM WE GET. PCPN SHOULD WIND DOWN FROM WEST
TO EAST DURING THE EVENING. HIGH PRESSURE BUILDS IN THURSDAY FOR
DRY BUT COOLER TEMPERATURES.
FOCUS WILL BE ON THE EASTERN PACIFIC WAVE THAT MOVES ACROSS THE
NORTHERN TIER STATES FRIDAY AND SATURDAY. MODEL CONSENSUS IS STILL
POOR WITH THE 00 UTC ECMWF STILL FARTHER NORTH...WARMER AND SLOWER
COMPARED TO THE GFS...WHICH IS MORE SIMILAR TO THE DGEX AND GEM.
STILL BEING 3 TO 4 DAYS OUT...WILL FAVOR A BLENDED SOLUTION...WHICH
PLACES BEST CHANCE FOR ACCUMULATING PRECIPITATION (RAIN/SNOW MIX)
ACROSS THE SOUTHERN FORECAST AREA WHERE 0.5 TO 0.75 INCHES LIQUID
EQUIVALENT IS POSSIBLE. THE GFS SOLUTION WOULD RESULT IN MORE
SNOW...WHEREAS THE WARMER ECMWF WOULD BE MOSTLY RAIN. SUNDAY SHOULD
BE MOSTLY DRY WITH ANOTHER SHOT OF PRECIPITATION ON MONDAY IN
ADVANCE OF THE NEXT UPPER LOW DIGGING ACROSS THE CENTRAL ROCKIES.
DAY-TO-DAY TEMPERATURE CHANGES WILL BE MINIMAL WITH DAYTIME HIGHS IN
THE 30S TO LOWER 40S AND NIGHTTIME LOWS IN THE 20S TO LOWER 30S.
OVERALL...NO MAJOR AIR MASS CHANGES IN THE NEXT SEVEN DAYS...KEEPING
TEMPERATURES WELL BELOW EARLY APRIL NORMALS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1150 PM CDT MON APR 1 2013
THERE IS A WEAK SHORTWAVE THAT WILL PASS THROUGH THE REGION
OVERNIGHT AND INCREASE CLOUD COVER. NOT SURE HOW WIDESPREAD THE
CLOUDS WILL BE...OR EXACTLY HOW LOW. JUDGING FROM UPSTREAM
SATELLITE IMAGERY AND RAP GUIDANCE...THERE WILL LIKELY BE A PERIOD
OF BKN CIGS IN THE LOW VFR RANGE (ESPECIALLY ALONG AND WEST OF THE
RED RIVER VALLEY).
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...VOELKER
LONG TERM...ROGERS
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1248 AM CDT TUE APR 2 2013
.UPDATE...
ISSUED AT 1247 AM CDT TUE APR 2 2013
NO SIGNIFICANT CHANGES WERE REQUIRED WITH THIS FORECAST UPDATE AS
THE INHERITED FORECAST FOR THE REMAINDER OF THE NIGHT IS WELL ON
TRACK AND BLENDED TO OBSERVED TRENDS THROUGH 530 UTC. THE ONLY
QUESTION FOR THE REMAINDER OF THE NIGHT IS HOW FAR INTO NORTHERN
NORTH DAKOTA EXPANDING STRATUS IN SOUTHEAST SASKATCHEWAN WILL BE
ABLE TO REACH. WILL FOLLOW CLOSELY TO THE 04 UTC RAP FOR LOW LEVEL
MOISTURE FIELDS FOR THE REMAINDER OF THE NIGHT AS IT CURRENTLY HAS
A GOOD DEPICTION OF THE STRATUS FIELD.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 346 PM CDT MON APR 1 2013
HIGH PRESSURE WILL GRADUALLY SHIFT EAST OF THE REGION THROUGH THE
PERIOD. DRY CONDITIONS WILL PREVAIL AS A RESULT. BELOW NORMAL
TEMPERATURES WILL CONTINUE THIS AFTERNOON AND TONIGHT.
HOWEVER...RETURN FLOW DEVELOPING ACROSS THE REGION COMBINED WITH NO
SNOW PACK SOUTHWEST OF THE MISSOURI WILL ALLOW TUESDAY AFTERNOON
HIGHS TO BE ABOVE NORMAL SOUTHWEST. BELOW NORMAL TEMPERATURES WILL
CONTINUE NORTH AND EAST OF THE MISSOURI RIVER...WHERE THE SNOW PACK
IS LOCATED.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 346 PM CDT MON APR 1 2013
THE MAIN FORECAST CHALLENGES FOR THE EXTENDED PERIOD INCLUDE
PRECIPITATION CHANCES AND PRECIPITATION TYPE. 12Z SUITE OF MODEL
SOLUTIONS ARE IN AGREEMENT EARLY IN THE PERIOD...WITH SOLUTIONS
DIVERGING LATE THIS WEEK.
WARM AIR ADVECTION WILL CONTINUE ACROSS THE AREA TUESDAY NIGHT AND
WEDNESDAY AHEAD OF A UPPER LEVEL WAVE/SURFACE LOW PRESSURE SYSTEM
THAT IS FORECAST TO PASS OVER NORTH DAKOTA. WARM H850
TEMPERATURES OF +6 TO +10C WILL BE FIRMLY IN PLACE WEDNESDAY AS
PRECIPITATION BEGINS ACROSS THE NORTHWEST AND SPREADS SOUTHEAST
ACROSS THE AREA WEDNESDAY. PRECIPITATION WILL BEGIN AS LIGHT
FREEZING RAIN AND TRANSITION TO LIGHT RAIN DURING WEDNESDAY
AFTERNOON. ACROSS THE SOUTHWEST...ISOLATED WEAK THUNDERSTORMS ARE
POSSIBLE...WHERE TEMPERATURES WILL BE IN THE 60S WITH SURFACE BASED
CAPE IN THE 100 TO 200 J/KG ADVERTISED BY THE 12Z NAM. BEFORE
ENDING WEDNESDAY EVENING...A TRANSITION FROM LIGHT RAIN TO A
WINTRY MIX OF SNOW...FREEZING RAIN...AND POSSIBLY SLEET WILL BE
SEEN AS A COLD FRONT MOVES SOUTH FROM CANADA.
COOLER TEMPERATURES WILL BE SEEN WEDNESDAY NIGHT AND THURSDAY...AS
COLD AIR COMMENCES FOLLOWING THE PASSAGE OF THE AFOREMENTIONED
COLD FRONT. HOWEVER...ACROSS THE SNOW LESS AREAS...TEMPERATURES
WILL BE WARMEST WITH TEMPERATURES IN 50S ON THURSDAY. FOR
LOCATIONS ACROSS THE SNOWPACK...TEMPERATURES WILL BE IN THE LOW TO
MID 30S.
STARTING FRIDAY...AN ACTIVE PERIOD OF WEATHER IS EXPECTED
TO START AS A SERIES OF UPPER LEVEL WAVES AND THEIR SURFACE
REFLECTIONS ARE PROGGED TO MOVE ACROSS THE AREA IN NORTHWESTERLY
FLOW. UNCERTAINTY REMAINS IN THE PLACEMENT AND TYPE OF
PRECIPITATION ACROSS NORTH DAKOTA...AS THERE IS DISAGREEMENT
AMONGST THE 12Z MODEL SOLUTIONS. THE 12Z GEM/GFS ARE MORE
AGGRESSIVE WITH QPF ACROSS THE WEST AND CENTRAL VERSUS THE 12Z EC
SOLUTION. THE 12Z EC KEEPS THE BULK OF THE PRECIPITATION FURTHER
NORTH ACROSS SOUTHERN MANITOBA AND SASKATCHEWAN.
AT THIS TIME HAVE UTILIZED A BLEND OF MODEL SOLUTIONS DURING THE
FRIDAY TO MONDAY PERIOD...WHICH GIVE A WIDE ARRAY OF PRECIPITATION
TYPES. AT THIS MOMENT...IT LOOKS LIKE THE SOUTHWEST WILL REMAIN
MOSTLY RAIN AS IT REMAINS IN THE WARM H850 TEMPERATURES OF +4 TO
+8 C. ELSEWHERE...A LIGHT WINTRY MIX OF SNOW...FREEZING RAIN...AND
POSSIBLY SLEET MAY OCCUR. BY SUNDAY EVENING AND
MONDAY...PRECIPITATION TYPE WILL BE SNOW...AS ANOTHER COLD FRONT
DROPS SOUTH OUT OF CANADA. FOLLOWING THE PASSAGE OF THE COLD
FRONT...COLDER H850 TEMPERATURES OF -8 TO -12 C ARE POSSIBLE AT
THE BEGINNING OF NEXT WEEK...AS A SURFACE HIGH PRESSURE STARTS TO
MOVE SOUTH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)...
ISSUED AT 1247 AM CDT TUE APR 2 2013
VFR CONDITIONS ARE FORECAST FOR THE 06 UTC TAF PERIOD ACROSS
WESTERN AND CENTRAL NORTH DAKOTA WITH HIGH PRESSURE IN PLACE.
THERE IS THE POTENTIAL THAT AN EXPANDING STRATUS FIELD ACROSS
SOUTHEAST SASKATCHEWAN AS OF 530 UTC MAY APPROACH THE KMOT
TERMINAL. DUE TO UNCERTAINTY CODED AS A TEMPO GROUP FOR MVFR
CEILINGS BETWEEN 8 AND 11 UTC AND WILL MONITOR SATELLITE TRENDS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...TM
LONG TERM...LTH
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1150 PM CDT MON APR 1 2013
.UPDATE...
ISSUED AT 1150 PM CDT MON APR 1 2013
NO UPDATE NEEDED AT THIS POINT AS CURRENT FORECAST IS ON TRACK
WITH PREVIOUS THINKING (SEE 945 PM UPDATE).
UPDATE ISSUED AT 945 PM CDT MON APR 1 2013
SHORTWAVE AND ASSOCIATED CLOUDS CONTINUE TO APPROACH THE REGION
FROM THE NORTHWEST. TIMED CLOUDY SKIES INTO THE FA BY LATER
TONIGHT AND INTO TUESDAY MORNING. SOME FLURRIES REPORTED
UPSTREAM...BUT MODELS DRY THIS ACTIVITY AS IT APPROACHES. NO
CHANGES NEEDED TO MIN TEMPS AS ANY CLOUD COVER WILL ARRIVE WELL
AFTER MIDNIGHT. MINOR ADJUSTMENTS TO THE HOURLY TEMPERATURE GRIDS
ACROSS THE FAR NW FA TO ACCOUNT FOR CLOUDS ARRIVING JUST BEFORE
SUNRISE.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 317 PM CDT MON APR 1 2013
TONIGHT...MAIN FORECAST CHALLENGE WILL BE CLOUDS AND TEMPS.
MODELS SEEM TO BE IN FAIR AGREEMENT SO WILL CONTINUE TO USE A
MODEL BLEND. NEVER SAW MUCH FOR CLOUD DEVELOPMENT TODAY SO WILL
START OFF THE NIGHT NEARLY CLOUD FREE. THERE IS AN UPSTREAM WAVE
OVER CENTRAL SASKATCHEWAN WITH SOME CLOUDS AND EVEN SOME FLURRIES
OR LIGHT SNOW ASSOCIATED WITH IT. AMERICAN MODELS HAD BEEN TRYING
TO HOLD SOME OF THIS LIGHT PCPN TOGETHER ALL THE WAY INTO THE
NORTHERN FA LATE. 12Z RUNS OF THE NAM/GFS STILL HOLD IT TOGETHER
BUT SEEM TO ERODE IT EITHER BEFORE IT GETS INTO OUR FA...WHILE
THE ECMWF REMAINS DRY. THEREFORE WILL KEEP THE FORECAST DRY
TONIGHT. AS FAR AS TEMPS GO SFC HIGH PRESSURE STILL REMAINS OVER
THE FA WITH SOME PRETTY LIGHT WINDS. WILL STICK WITH LOWS TONIGHT
FAIRLY SIMILAR TO THOSE FROM THIS MORNING.
TUE...SFC HIGH REMAINS IN CLOSE PROXIMITY TO THE RED RIVER VALLEY
KEEPING WINDS ON THE LOW SIDE AGAIN. LINGERING CLOUD COVER MAY
HAVE SOME INFLUENCE ON HIGHS FOR THE DAY. GENERALLY KEPT HIGHS
ABOUT 5F WARMER THAN TODAY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 317 PM CDT MON APR 1 2013
TUE NIGHT-THU...WED IS STILL ON TRACK TO BE THE WARMEST DAY OF THE
WEEK WITH 850MB TEMPS REACHING UP INTO THE +6C TO +8C RANGE OVER
PORTIONS OF THE FA WITH A LITTLE STEADIER SOUTH WINDS. MAYBE NOT
THE BEST DIRECTION FOR REALLY GOOD WARMING BUT AS THE COLD FRONT
COMES THRU THEY SHOULD SWITCH TO THE WEST THEN NW. STILL LOOKS
LIKE A LITTLE BIT OF PCPN WILL COME THROUGH WITH THE COLD FRONT
BUT TRIED TO NARROW DOWN THE WINDOW A BIT BETTER. SHOULD REALLY BE
A QUICK SHOT ALONG THE FRONT AND TEMPS SHOULD BE WARM ENOUGH TO
KEEP ANY PCPN IN THE LIQUID FORM UNLESS MORE PCPN LINGERS BEHIND
THE FRONT. THU WOULD BE COOLER BEHIND THE FRONT.
THU NIGHT-MON...AN ENERGETIC JET STREAM WITH SOMEWHAT FLATTENED
LONGWAVE RIDGE PATTERN IN THE LATE WEEK THEN TRANSITIONS TO A
BROAD WESTERN TROF OVER THE WEEKEND. THIS PRODUCES A BRIEF RETURN
TO NORTHWEST MID LEVEL FLOW OVER THE AREA ON THURSDAY AND A SUBTLE
/FEW DEGREE/ COOL DOWN BEHIND A SURFACE COLD FRONT. A RETURN
SOUTHERLY BLAYER FLOW IS EXPECTED ON FRIDAY... WITH ALL LONG RANGE
MODELS ANTICIPATING THE ADVANCE OF A COLORADO LOW INTO THE CENTRAL
AND NORTHERN PLAINS BY SATURDAY. A RAIN/SNOW MIX LOOKS QUITE
PROBABLE FOR MUCH OF THE AREA FROM FRIDAY EVENING INTO SATURDAY...
WITH A SOMEWHAT COOLER AND DRIER PATTERN ON SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1150 PM CDT MON APR 1 2013
THERE IS A WEAK SHORTWAVE THAT WILL PASS THROUGH THE REGION
OVERNIGHT AND INCREASE CLOUD COVER. NOT SURE HOW WIDESPREAD THE
CLOUDS WILL BE...OR EXACTLY HOW LOW. JUDGING FROM UPSTREAM
SATELLITE IMAGERY AND RAP GUIDANCE...THERE WILL LIKELY BE A PERIOD
OF BKN CIGS IN THE LOW VFR RANGE (ESPECIALLY ALONG AND WEST OF THE
RED RIVER VALLEY).
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...GODON
LONG TERM...GUST
AVIATION...TG
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
1223 AM CDT TUE APR 2 2013
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...CIG MAY BE A BIT INTERMITTENT NEAR THE COAST BUT A
PREDOMINANT MVFR LAYER AT ABOUT 1100 TO 1300 FT IS EXPECTED FOR
THE NEXT FEW HOURS. NEAR THE COAST TEMPORARY DROPS TO ABOUT 800FT
WILL BE POSSIBLE AROUND SUNRISE. MVFR CIGS NEAR THE COAST THROUGH
MOST OF THE MORNING HOURS LIKELY SCATTERING OUT IN THE AFTERNOON.
VFR WILL OCCUR EARLIER INLAND. WINDS WILL BE MODERATE OUT OF THE
EAST TO SOUTHEAST. THERE IS A SMALL CHANCE FOR SHOWERS OR
THUNDERSTORMS...MAINLY OVER THE BRUSH COUNTRY BUT LEFT THOSE OUT
OF THE TAFS FOR NOW. LOWERING CIGS EXPECTED AGAIN TUESDAY NIGHT. /68-JGG/
&&
.PREV DISCUSSION... /ISSUED 208 PM CDT MON APR 1 2013/
SHORT TERM /NOW THROUGH TUESDAY NIGHT/...THE AREA REMAINS IN
QUASI-ZONAL FLOW ALOFT WITH AN UPPER LEVEL TROUGH LOCATED OVER THE
GREAT BASIN AND A WEAK IMPULSE RIDING WESTERLY FLOW IN NORTHERN
MEXICO SOUTH OF THE TEXAS BIG BEND. AT THE SURFACE...SOUTHEASTERLY
FLOW CONTINUES TO ADVECT MOISTURE FROM THE GULF OF MEXICO WITH A
COLD FRONT LOCATED ACROSS OKLAHOMA AND THE TEXAS PANHANDLE. A
1020MB HIGH IS LOCATED ACROSS THE ARKLAMISS.
FOR THE REST OF THE AFTERNOON AND INTO THIS EVENING...WILL CONTINUE
TO SEE CLOUDS BREAK UP AS MIXING AND DAYTIME HEATING CONTINUES.
THICKER STRATOCU RESIDES OVER ZAPATA/JIM HOGG/STARR COUNTIES AND MAY
BE A LITTLE HARDER TO BREAK UP CLOUDS IN THIS AREA. EVEN THOUGH
THICK CLOUDS ARE LOCATED HERE...TEMPERATURES HAVE WARMED NICELY AND
ARE ACTUALLY ABOVE FORECASTED HOURLY TEMPERATURES BUT LOOK GOOD FOR
THE HIGHS THIS AFTERNOON. WEAK IMPULSE TO OUR WEST IS FORECAST TO
SPARK CONVECTION ON THE SIERRA MADRE LATER THIS AFTERNOON AS IT
MOVES EAST. LATEST HRRR AND SPC 4KM WRF CONTINUE TO ROLL CONVECTION
OFF THE HIGHER TERRAIN AND MAKE A RUN AT OUR WESTERN ZONES. CURRENT
20 POPS OUT WEST LOOK GOOD FOR THIS EVENING AND MADE ONLY MINOR
ADJUSTMENTS TO MOVE JUST A LITTLE EASTWARD. ANY STORMS THAT DO CREEP
INTO OUR AREA WILL QUICKLY DISSIPATE TOWARDS MID EVENING AS BOUNDARY
LEVEL STABILIZES.
FOR TONIGHT...LOW CLOUDS WILL MOVE BACK IN ON SOUTHEASTERLY LOW
LEVEL WINDS BY MID TO LATE EVENING. NAM12/RAP/HRRR SHOW SIGNALS OF
SEA FOG DEVELOPING AND/OR ADVECTING IN TO THE COASTAL AREAS
OVERNIGHT. ADDED AREAS OF FOG ALONG THE COASTLINE WITH PATCHY FOG
INLAND. WILL HOLD OFF ON ANY DENSE FOG ADVISORY AT THIS TIME AND LET
SWING SHIFT MAKE THE CALL. INCREASED LOW TEMPERATURES SLIGHTLY WITH
EXPECTED ABUNDANCE OF LOW CLOUDS AND LOOKING AT MAINLY UPPER 60S TO
LOWER 70S.
FOR TUESDAY...WE WILL START OUT WITH THOSE LOW CLOUDS AND WILL BREAK
OUT AND DISSIPATE BY LATE MORNING. MIXING WILL TAKE PLACE BY MID
MORNING WITH GUSTY WINDS BY LATE MORNING. ANOTHER IMPULSE IS PROGGED
TO MOVE ACROSS THE AREA EARLY TUESDAY AFTERNOON. THERE IS PLACEMENT
ISSUES BETWEEN THE NAM AND GFS WITH THE NAM FURTHER NORTH AND THE
GFS IS ACROSS THE NORTHERN PORTION OF THE AREA AND IS WEAKER THAN
THE PREVIOUS RUN. KEPT POPS AS IS AND JUST TWEAKED LOCATION BASED ON
12Z GFS. A STRONG TO SEVERE STORM IS POSSIBLE GIVEN THE
THERMODYNAMIC ENVIRONMENT.
FOR TUESDAY NIGHT...THAT IMPULSE IS WELL NORTH OF THE AREA WITH JUST
A FEW SHOWERS LEFT OVER IN THE COASTAL WATERS. ATMOSPHERE WILL
STABILIZE RATHER RAPIDLY AFTER SUNSET WITH SKIES BECOMING CLOUDY
ONCE AGAIN. COLD FRONT WILL SAG INTO NORTH CENTRAL TEXAS WITH A SFC
LOW SOUTH OF THE TEXAS BIG BEND. CLOUDS WILL KEEP LOWS
UP...COMPARABLE TO TONIGHT.
LONG TERM /WEDNESDAY THROUGH MONDAY/...12Z MODEL RUN REMAINS
PERSISTENT ON THE TRACK AND STRENGTH OF THE MID TO UPPER LEVEL
TROUGH CURRENTLY OVER THE GREAT BASIN. BY 18Z WEDNESDAY GFS PLACES
THE UPPER TROUGH AXIS ACROSS NORTHWEST TEXAS AROUND 18Z WITH ITS
ASSOCIATED COLD FRONT APPROACHING THE NORTHERN PORTIONS OF THE
CWA. LARGE SCALE ASCENT COUPLED WITH LOW LEVEL CONVERGENCE ALONG
THE FRONT SHOULD BE THE COMBINATION NEEDED TO BRING ABOUT THE
CHANCE OF RAIN WE HAVE SEEN IN A WHILE. MODEST LOW LEVEL MOISTURE
WILL BE IN PLACE AND A LATE AFTERNOON FRONTAL PASSAGE SHOULD ALLOW
FOR SURFACE HEATING TO EXCEED GUIDANCE VALUES. SPC MAINTAINS
GENERAL THUNDERSTORM CHANCES FOR WEDNESDAY BUT CAN NOT RULE OUT
ISOLATED SEVERE STORMS AS THE ATMOSPHERE BECOMES INCREASINGLY
UNSTABLE. A DAY TO DAY ANALYSIS TO TAKE PLACE BEFORE WE ADD SEVERE
WORDING INTO THE FORECAST/GRIDS. POP GUIDANCE REMAINS AT LOW END
CHANCE BUT THIS MIGHT BE ON THE LOW END WITH DYNAMICS LOOKING A
BETTER THEN YESTERDAY AT THIS TIME. KEEP WED AND WEDNESDAY NIGHT
POPS CLOSE TO THE PREVIOUS FORECAST. AS MENTIONED TEMPERATURES
SHOULD CLIMB AHEAD OF THE COLD FRONT WITH A LATE AFTERNOON OR
EARLY EVENING PASSAGE. FORECAST HIGHS TO REMAIN ABOVE GUIDANCE
VALUES ESPECIALLY IF WE SEE MORE SUN PEAK THROUGH.
TROUGH AXIS AND SURFACE LOW PRESSURE QUICKLY EXITS TO THE EAST
THURSDAY MORNING. HUNG ON TO LOW POPS ACROSS THE COASTAL COUNTIES
BEFORE ENDING THURSDAY AFTERNOON AS THIS SYSTEM OPENS AND PUSHES
TO THE EAST. FAIR WEATHER ENSUES THURSDAY AFTERNOON INTO FRIDAY AS
SHORTWAVE RIDGING BUILDS OVERHEAD. COOL TO MILD TEMPERATURES
THURSDAY MORNING WITH SOME RECOVERY THURSDAY WITH HIGHS DROPPING
TO SLIGHTLY EARLY APRIL NORMALS.
GFS HAS BEEN INDICATING A QUICK RETURN OF GULF MOISTURE FRIDAY
NIGHT INTO SATURDAY. A WEAK DISTURBANCE IN THE ZONAL FLOW HAS BEEN
SEEN THE LAST FEW RUNS. ALTHOUGH GUIDANCE IS SHOWING VERY LOW POPS
ON SATURDAY WILL UP THE CHANCES SLIGHTLY TO MENTION ISOLATED
SHOWERS. MODEST DIVERGENCE AND SUFFICIENT MOISTURE...IF OCCURS
MIGHT BE ENOUGH FOR A FEW SHOWERS. WIND MACHINE TO POSSIBLY TURN
ON SUNDAY AND MONDAY AS NEXT TROUGH AND SURFACE LOW DEVELOP OUT
WEST. TEMPERATURES TO CLIMB AS USUAL.
MARINE /NOW THROUGH TUESDAY/GENERALLY FAVORABLE MARINE CONDITIONS
ARE EXPECTED THROUGH TUESDAY NIGHT WITH MODERATE EASTERLY TO
SOUTHEASTERLY WINDS. CONDITIONS MAY APPROACH EXERCISE CAUTION
LEVELS ON THE GULF OF MEXICO TONIGHT. SEAS SHOULD REMAIN LOW TO
MODERATE.
WEDNESDAY THROUGH SUNDAY...COLD FRONT ON TAP FOR A LATE WEDNESDAY OR
WEDNESDAY EVENING PASSAGE. LIGHT WINDS IN ADVANCE OF THE FRONT TO
SHIFT AND INCREASE FROM THE NORTH. SMALL CRAFT ADVISORIES STILL
EXPECTED WITH A 6 TO 12 HOUR WINDOW OF STRONG NORTH FLOW WEDNESDAY
NIGHT INTO EARLY THURSDAY AS SURFACE LOW PRESSURE DEVELOPS EAST OF
PADRE ISLAND ALONG THE FRONT. WITH THE SURFACE LOW TRACKING EAST
FAIRLY QUICKLY THURSDAY NORTH TO NORTHEAST WINDS TO WEAKEN. WINDS
VEER FRIDAY TO THE EAST AND SOUTHEAST BY FRIDAY NIGHT BUT THE
RETURN FLOW REMAINS LIGHT TO MODERATE. MORE SUBSTANTIAL INCREASE
OF SOUTHEAST WINDS RESUME SUNDAY INTO MONDAY AS THE GRADIENT
TIGHTENS WITH LOW PRESSURE DEEPENING ACROSS WESTERN TEXAS AND
NORTHEAST MEXICO.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
68/60
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
307 AM CDT TUE APR 2 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 307 AM CDT TUE APR 2 2013
LATEST WATER VAPOR IMAGERY AND 500 MB RAP ANALYSIS SHOWED NORTHWEST
FLOW ALOFT ACROSS THE UPPER MISSISSIPPI RIVER VALLEY EARLY THIS
MORNING. A SHORTWAVE TROUGH WAS NOTED OVER SOUTHERN MANITOBA
RACING SOUTHEAST TOWARD THE AREA. SURFACE OBSERVATIONS INDICATED
HIGH PRESSURE STRETCHING FROM THE EASTERN DAKOTAS SOUTHEAST INTO
THE MIDDLE MISSISSIPPI RIVER VALLEY. THE HIGH WILL SLIDE EAST INTO
THE AREA TODAY. MEANWHILE THE SHORTWAVE TROUGH WILL MOVE THROUGH
BUT WILL DO LITTLE MORE THAN PRODUCE AN INCREASE IN CLOUD OVER
NORTHERN AND CENTRAL WISCONSIN WITH THE REST OF THE FORECAST AREA
EXPERIENCING MOSTLY SUNNY SKIES. PLAN ON HIGHS TODAY RANGING FROM
THE LOWER 30S OVER NORTHERN WISCONSIN TO THE UPPER 30S TO AROUND
40 ACROSS NORTHEAST IOWA. THE HIGH IS EXPECTED TO SLIDE OVER THE
AREA TONIGHT PROVIDING QUIET WEATHER. ANOTHER UNSEASONABLY COLD
NIGHT IS IN STORE FOR THE FORECAST AREA WITH LOWS FALLING INTO THE
UPPER TEENS TO LOWER 20S. FAVORED COLD SPOTS OVER NORTH CENTRAL
WISCONSIN...SUCH AS DIAMOND LAKE...COULD SEE LOWS FALL INTO THE
SINGLE DIGITS ABOVE ZERO.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 307 AM CDT TUE APR 2 2013
HIGH PRESSURE WILL CONTINUE TO DOMINATE THE WEATHER ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY ON WEDNESDAY WITH MOSTLY SUNNY SKIES
EXPECTED. THE SURFACE HIGH WILL SLIDE EAST LATE IN THE DAY AS A WEAK
COLD FRONT MOVES EAST OUT OF THE DAKOTAS. SOUTHERLY FLOW WILL
INCREASE ACROSS THE AREA AHEAD OF THIS FEATURE HELPING
TEMPERATURES WARM SLIGHTLY. PLAN ON HIGH TEMPERATURES RANGING FROM
THE LOWER 40S OVER NORTHCENTRAL WISCONSIN TO THE UPPER 40S TO
AROUND 50 ACROSS NORTHEAST IOWA. THE FRONT IS EXPECTED TO SAG
SOUTHEAST WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING AS A TROUGH
PUSHES EASTWARD ACROSS ONTARIO. FORECAST MODELS CONTINUE TO
GENERATE SOME LIGHT PRECIPITATION ALONG THE FRONT AS IT MOVES INTO
THE FORECAST AREA LATE WEDNESDAY NIGHT INTO THURSDAY MORNING.
FORCING IS NOT OVERLY IMPRESSIVE WITH THIS FEATURE WITH ONLY WEAK
ISENTROPIC LIFT NOTED. THE UPPER LEVEL FORCING IS PASSING WELL TO
THE NORTH OF THE REGION SO NOT EXPECTING MUCH PRECIPITATION.
HOWEVER...CANNOT RULE OUT SOME AREAS MEASURING SOME LIGHT RAIN MAINLY
ALONG AND NORTH OF INTESTATE 90. SOME SNOW COULD MIX IN EARLY IN
THE NORTH BEFORE TEMPERATURES WARM. HIGHS ON THURSDAY ARE EXPECTED
TO RANGE FROM LOWER TO MID 40S OVER NORTHCENTRAL WISCONSIN TO THE
LOWER 50S ACROSS NORTHEAST IOWA. THE FRONT WILL MOVE SOUTH AND
BECOME STATIONARY STRETCHING FROM THE WESTERN SOUTH DAKOTA EAST
THROUGH CENTRAL IOWA INTO NORTHERN ILLINOIS.
SURFACE HIGH PRESSURE IS EXPECTED TO RETURN BRIEFLY ON FRIDAY
PROVIDING ANOTHER QUIET DAY. MEANWHILE...A POTENT SHORTWAVE LOOKS TO
MOVE ACROSS THE PACIFIC NORTHWEST AND RACE EAST THROUGH THE DAKOTAS
LATE FRIDAY NIGHT. THE STATIONARY FRONT WILL LIFT NORTH AS THE WAVE
MOVES EAST AND ACT AS A BAROCLINIC ZONE. SURFACE LOW PRESSURE IS
EXPECTED TO DEVELOP ACROSS WESTERN SOUTH DAKOTA LATE FRIDAY
NIGHT...THEN MOVES EAST INTO THE UPPER MISSISSIPPI RIVER VALLEY
DURING THE DAY ON SATURDAY. STRONG 850 MB WARM AIR ADVECTION
DEVELOPS OVER THE AREA AHEAD OF THE APPROACHING LOW FRIDAY NIGHT
INTO SATURDAY MORNING. ISENTROPIC LIFT...ON THE 285-305K
SURFACES...INCREASES RAPIDLY AS THE LOW MOVES INTO THE AREA. THE
FORECAST MODELS HAVE BEEN SHOWING SOME DIFFERENCES REGARDING THE
PLACEMENT OF THE BOUNDARY WHICH WILL HAVE A HUGE IMPACT ON
PRECIPITATION TYPES. AT THIS TIME IT APPEARS THAT THE MAIN
PRECIPITATION TYPE WILL BE RAIN WITH PLENTY OF WARM AIR ADVECTING
NORTHWARD INTO THE REGION AHEAD OF THIS SYSTEM. THE PRECIPITATION
COULD START OUT AS SNOW EAST OF THE MISSISSIPPI RIVER LATE FRIDAY
NIGHT BUT SHOULD QUICKLY TRANSITION OVER TO ALL RAIN EARLY SATURDAY
MORNING. THE GEM AND GFS OFFER SIMILAR SOLUTIONS WITH THIS
SYSTEM...TAKING THE SURFACE LOW OVER SOUTHERN MINNESOTA ON SATURDAY
THEN ACROSS SOUTHERN WISCONSIN SATURDAY NIGHT. THE ECMWF OFFERS A
SLOWER AND MORE NORTHERLY SOLUTION...TAKING THE LOW OVER CENTRAL
MINNESOTA THROUGH NORTHERN WISCONSIN SATURDAY NIGHT. THE ECMWF
SOLUTION WOULD BRING MILD AIR INTO THE REGION ON SATURDAY...WITH
HIGHS CLIMBING INTO THE UPPER 50S TO LOWER 60S. ON THE OTHER HAND
THE GFS/GEM SOLUTION ARE ON THE COOLER SIDE WITH HIGHS RANGING
FROM THE UPPER 30S/LOWER 40S OVER NORTHERN WISCONSIN TO THE MID
50S ACROSS NORTHEAST IOWA. WILL LEAN TOWARDS A MODEL CONSENSUS
BLEND APPROACH. PLAN ON HIGHS RANGING FROM THE LOWER 40S OVER
NORTH CENTRAL WISCONSIN TO THE MID TO UPPER 50S SOUTH OF
INTERSTATE 90. THE LOW IS EXPECTED TO EXIT THE REGION ON SUNDAY.
AN ACTIVE PATTERN LOOKS TO DEVELOP MONDAY INTO TUESDAY AS A TROUGH
DIGS INTO THE SOUTHWEST CONUS. SOUTHWEST FLOW ALOFT COULD SET UP
OVER THE AREA. THE BAROCLINIC ZONE LOOKS TO REMAIN OVER THE UPPER
MIDWEST AS SHORTWAVE ENERGY EJECTS OUT OF OF THE SOUTHWEST FLOW
AND INTERACTS WITH IT. LATEST GUIDANCE SUGGESTS THE BOUNDARY WILL
STRETCH FROM NORTHERN OHIO WESTWARD THROUGH NORTHERN ILLINOIS
THROUGH SOUTHERN IOWA. WILL HAVE TO KEEP A CLOSE WATCH ON FUTURE
MODEL RUNS WITH THE POTENTIAL FOR THIS ACTIVE PATTERN TO BRING
SEVERAL ROUNDS OF PRECIPITATION TO THE REGION.
&&
.AVIATION...TONIGHT AND TUESDAY
631 PM CDT MON APR 1 2013
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD WITH SURFACE HIGH
BEING THE DOMINATE WEATHER FEATURE. A WEAK SHORTWAVE TROUGH WILL
DROP ACROSS THE AREA TUESDAY WHICH WILL ONLY PRODUCE SOME
SCATTERED MID LEVEL CLOUDS. NORTHWEST WINDS WILL CONTINUE AT 5 TO
10 KNOTS TONIGHT AND AROUND 12 KNOTS TUESDAY AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 307 AM CDT TUE APR 2 2013
THE COMBINATION OF SNOW MELT AND THE RAIN OVER THE WEEKEND HAS
RESULTED IN FLOODING ALONG THE TREMPEALEAU RIVER AT DODGE. THE
LATEST STAGE WAS 9.21FT. FLOOD STAGE IS 9FT. THE RIVER IS
EXPECTED TO CREST THIS MORNING AND THEN SLOWLY FALL LATE THIS
AFTERNOON INTO THIS EVENING.
THE BLACK RIVER HAS CRESTED BELOW FLOOD STAGE AT BLACK RIVER
FALLS. WITH PLENTY OF SNOW UPSTREAM...THIS RIVER WILL LIKELY STAY
HIGH FOR THE NEXT SEVERAL DAYS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...RABERDING
HYDROLOGY...WETENKAMP
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
345 AM MDT TUE APR 2 2013
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 345 AM MDT TUE APR 2 2013
AREA OF LOW PRESSURE DETACHED FROM THE MEAN FLOW WILL SLOWLY MOVE
OUT OF UTAH THIS MORNING AND INTO THE SOUTHERN PLAINS BY WEDNESDAY
NIGHT. THE FEW WEAK SHOWERS THAT HAVE PUSHED NORTHEAST ACROSS THE
CO/WY STATELINE HAVE DISSIPATED QUICKLY LOSING BEST QG VERTICAL
VELOCITIES WHICH ARE WELL SOUTH OF THE CWFA. ALTHOUGH STILL CANT
RULE OUT ISOLATED TO LOCALLY SCATTERED SHOWERS/DRIZZLE THROUGH THE
AFTERNOON...THESE WILL NEED TO RELY MAINLY ON LFQ H3 JET HELP AND
INSTABILITY. AS A RESULT...HAVE DECREASED PRECIPITATION CHANCES SOME
ESPECIALLY THIS MORNING...KEEPING THE HIGHEST IN AREAS NR THE CO/WY
STATELINE AND ALONG THE I80 CORRIDOR. ADDITIONALLY...PROGD LIFTED
INDICES WILL FALL SLIGHTLY NEGATIVE FOR AREAS WEST OF THE LARAMIE
RANGE THIS AFTERNOON. SO KEPT THE MENTION OF THUNDER FOR THESE
AREAS. ALTHOUGH WOULD EXPECT THE BEST THUNDER POTENTIAL TO BE OVER
THE SNOWY/SIERRA MADRE RANGES. THE OTHER CONCERN THIS MORNING IS
PATCHY FOG THAT HAS DEVELOPED ALONG THE INTERSTATE 80 SUMMIT. THE
AFFECTED AREA HAS THUS FAR BEEN CONFINED TO A FEW MILE STRETCH OF
I80. LATEST HRRR EVEN SHOWS SOME OF THIS STRATUS DESCENDING ALONG
THE EASTERN FOOTHILLS OF THE SOUTHERN LARAMIE RANGE TOWARDS DAYBREAK
AS WELL. FOR NOW...HAVE ADDED FOG MENTION TO THIS AREA THROUGH
MID-MORNING. H7 TEMPERATURES HOVERING AROUND -3C COMBINED WITH
THICKER CLOUD-COVER WILL TEMPER AFTERNOON HIGH TEMPERATURES
SOMEWHAT...WITH MAINLY 50S EXPECTED. THE EXCEPTION WILL BE AREAS IN
AND AROUND THE SOUTHEAST WYOMING MOUNTAINS WHERE HIGHS WILL ONLY
REACH THE 40S.
LATEST MODEL GUIDANCE HINTS AT THE POSSIBILITY OF PATCHY FOG FROM
CHEYENNE TO SIDNEY AGAIN LATER TONIGHT AND EARLY WEDNESDAY. SO HAVE
ADDED PATCHY MENTION. EXPECT MAINLY DRY CONDITIONS TONIGHT AS BEST
MOISTURE/LIFT ASSOCIATED WITH THE UPPER LOW EXITS TO THE SOUTHEAST
OF THE AREA.
HEIGHTS WILL RISE BEHIND THE DEPARTING LOW PRESSURE SYSTEM ON
WEDNESDAY. EXPECT A MOSTLY DRY DAY AS THIS WEAK TRANSITORY RIDGE
TRANSITIONS TO NORTHWEST FLOW. H7 TEMPERATURES WILL CLIMB TO
FREEZING AND WITH LESS CLOUD-COVER WILL SEE HIGHS CLIMB WELL INTO
THE 50S AND 60S AT ALL LOWER ELEVATIONS. MAY EVEN FLIRT WITH 70
NORTH OF THE PINE RIDGE. MODELS POINT TO ANOTHER WEAK FRONT WILL
PUSH SOUTH THROUGH THE AREA WEDNESDAY NIGHT. MOISTURE LOOKS TO BE
LIMITING FACTOR...SO KEPT WEDNESDAY NIGHT DRY FOR NOW.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 345 AM MDT TUE APR 2 2013
UPPER RIDGE WILL SHIFT EAST ACROSS THE CWA THURSDAY AND THURSDAY
NIGHT RESULTING IN MILD AND DRY WEATHER THROUGH MOST OF FRIDAY.
NEXT UPPER TROUGH TO AFFECT THE REGION WILL APPROACH ON FRIDAY AND
MAY SPREAD SOME SHOWERS INTO FAR WESTERN AND NORTHERN PARTS OF THE
CWA LATE IN THE DAY. THIS SYSTEM WILL PASS ACROSS FRIDAY NIGHT
BRINGING A MODEST PACIFIC FRONT AND A LITTLE COOLER TEMPERATURES
FOR SATURDAY. YET ANOTHER SHORTWAVE SHOULD PASS BY SATURDAY NIGHT
BEFORE A MORE SIGNIFICANT TROUGH DIGS OVER THE WESTERN CONUS
SUNDAY NIGHT AND MONDAY SPREADING MORE WIDESPREAD RAIN AND SNOW
SHOWERS ACROSS THE CWA AT THAT TIME. TEMPERATURES WILL ALSO COOL
SUNDAY THROUGH MONDAY DUE TO MORE CLOUD COVER AND LOWERING
HEIGHTS. MODELS SHOW THIS SYSTEM COULD BE A DECENT PRECIPITATION
PRODUCER FOR THE CWA EARLY NEXT WEEK BUT WILL SEE HOW FUTURE RUNS
TURN OUT BEFORE GETTING TOO EXCITED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1209 AM MDT TUE APR 2 2013
AN AREA OF LOW PRESSURE SPINNING THROUGH UTAH EARLY THIS MORNING
WILL VERY SLOWLY PUSH INTO COLORADO BY LATE TODAY. AS A RESULT...ITS
IMPACT WILL BE CONFINED TO SE WYOMING TERMINALS IN THE WAY OF
MVFR/IFR CIGS/VSBYS THROUGH AROUND 18Z TUESDAY. WILL SEE PERIODIC
BANDS OF WEAK SHOWERS LIFTING NORTHEAST AND HAVE INCLUDED MENTION
PRIMARILY AT KCYS DURING THE MORNING HOURS. CONFIDENCE IS LESS AT
KRWL AND KLAR...THUS HAVE LEFT VCSH IN UNTIL TIMING CAN BE NARROWED.
CONDITIONS WILL IMPROVE ACROSS SE WYOMING BY THIS AFTERNOON.
OTHERWISE...EXPECT VFR CONDITIONS AT WESTERN NEBRASKA PANHANDLE
AIRFIELDS THROUGH THE FORECAST PERIOD.
&&
.FIRE WEATHER...
ISSUED AT 345 AM MDT TUE APR 2 2013
MINIMAL FIRE WEATHER CONCERNS EXPECTED THIS WEEK. AN AREA OF LOW
PRESSURE WILL MOVING FROM UTAH INTO COLORADO TODAY. CLOUDS AND LIGHT
PRECIPITATION CHANCES WILL HOLD HIGH TEMPERATURES DOWN AND MINIMUM
RELATIVE HUMIDITIES UP TODAY. THERE WILL BE UP TO A FEW INCHES OF
NEW SNOW OVER THE SNOWY AND SIERRA MADRES THROUGH TODAY.
PRECIPITATION WILL DECREASE TONIGHT...WITH DRIER CONDITIONS SETTLING
IN FOR WEDNESDAY THROUGH FRIDAY. WARMER TEMPERATURES ARE EXPECTED AS
WELL...WITH 70S RETURNING TO EASTERN PORTIONS OF THE DISTRICT BY
WEEKS END. MINIMUM RELATIVE HUMIDITIES WILL HOVER IN THE 20 TO 30
PERCENT RANGE EACH DAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...HAHN
LONG TERM...RE
AVIATION...HAHN
FIRE WEATHER...HAHN
AREA FORECAST DISCUSSION
NWS MIAMI FL
1015 AM EDT TUE APR 2 2013
.UPDATE...
THE LATEST VISIBLE SATELLITE IMAGERY SHOWED THE LARGE STRATUS DECK
OVER MUCH OF THE INTERIOR SECTIONS CLEARING AND BURNING OFF AS OF
9-10AM. THIS CLEARING TREND WILL CONTINUE THROUGH THE LATE
MORNING HOURS WITH MOSTLY SUNNY SKIES EXPECTED THROUGH THE EARLY
AFTERNOON. THE LATEST OBSERVATIONS AROUND THE AREA INDICATED
VISIBILITIES HAVE IMPROVED SIGNIFICANTLY WITH NO RESTRICTIONS DUE
TO FOG. HOWEVER...SMOKE FROM THE WILDFIRE IN COLLIER COUNTY WILL
CONTINUE TO IMPACT SOME OF THE AREAS...WHICH INCLUDES I75 MOSTLY
IN COLLIER COUNTY WHERE A FEW AREAS OF THE HIGHWAY REMAIN CLOSED.
ELSEWHERE...ANOTHER PLEASANT DAY IS EXPECTED WITH HIGHS FORECAST
TO REACH THE LOWER 80S ALONG THE COAST TO THE MID TO UPPER 80S
FARTHER INLAND. LOW-LEVEL FLOW WILL QUICKLY SHIFT TO THE NORTH
AND NORTHEAST THROUGH THE AFTERNOON...WHICH SHOULD ALLOW FOR SOME
INCREASE IN LOW-LEVEL MOISTURE. THIS INCREASE IN MOISTURE COMBINED
WITH THE DAYTIME HEATING SHOULD INDUCE A LOW-LOW CU FIELD ACROSS
THE INTERIOR LOCATIONS AND POSSIBLY A FEW SHOWERS THROUGH THE LATE
AFTERNOON HOURS AS THE WEST COAST SEA BREEZE PUSHES INLAND.
&&
.PREV DISCUSSION... /ISSUED 745 AM EDT TUE APR 2 2013/
UPDATE...
FOR THE SHORT TERM...DENSE FOG CONTINUES TO AFFECT MOST OF THE
SOUTH FLORIDA PENINSULA. THE ONLY TERMINALS NOT CURRENTLY AFFECTED
WITH IFR VISIBILITY RESTRICTIONS ARE KMIA AND KOPF...BUT THESE
TERMINALS COULD EXPERIENCE BRIEF PERIODS OF MIST AND/OR FOG OVER
THE NEXT HOUR OR SO WITH SUB-VFR VIS RESTRICTIONS AND WILL AMEND AS
NECESSARY. OTHERWISE...BY MID MORNING AND THROUGH THE AFTERNOON
MAINLY VFR CONDITIONS EXPECTED ALL TERMINALS. WITH LIGHT VARIABLE
FLOW THIS MORNING...THE WEST AND EAST COAST SEA BREEZES ARE
EXPECTED TO FORM TODAY.
60
PREV DISCUSSION... /ISSUED 647 AM EDT TUE APR 2 2013/
UPDATE...
SHORT TERM MODELS CONTINUE TO INDICATE THE POSSIBILITY OF AN
AFTERNOON SHOWER IN THE INTERIOR PORTION OF THE STATE LATER THIS
AFTERNOON. THE MAIN FOCUS WILL BE THE CONVERGENCE OF THE SEA
BREEZE. CONFIDENCE IS STILL LOW, BUT FEEL THERE IS ENOUGH OF A
CHANCE TO PUT A MENTION IN THE FORECAST FOR TODAY.
PREV DISCUSSION... /ISSUED 447 AM EDT TUE APR 2 2013/
DISCUSSION...
THE WEATHER FOR THE MOST PART IS QUIET. THERE IS SOME DENSE FOG IN
THE WESTERN HALF OF THE FORECAST AREA, AND SOME LOCALIZED FOG NEAR
TAMIAMI. SO, A DENSE FOG ADVISORY IS IN PLACE FOR PORTIONS OF
SOUTH FLORIDA. THIS FOG SHOULD BURN OFF WITHIN A COUPLE OF HOURS
AFTER SUNRISE.
OTHERWISE, HIGH PRESSURE IS BUILDING IN TODAY. AREAS IN THE
INTERIOR PORTIONS OF THE STATE WILL SEE HIGH TEMPERATURES IN THE
MID TO UPPER 90S. COASTAL AREAS WILL SEE HIGHS IN THE LOW TO MID
80S. THERE SHOULD BE A DECENT SEA BREEZE TO DEVELOP TODAY. WITH
SOME MOISTURE, WILL HAVE TO WATCH FOR INDICATIONS THAT SOME
SHOWERS MAY DEVELOP IN THE INTERIOR, ESPECIALLY IF THERE IS ANY
SEA BREEZE CONVERGENCE. NAM MODEL SOUNDINGS ARE SHOWING A GOOD CAP
BETWEEN 500 AND 600 MB. THE HRRR IS HINTING THAT SOMETHING MAY
DEVELOP, BUT IT IS AT THE END OF ITS MODEL RUN AND WOULD LIKE TO
SEE WHAT IT DOES WITH THIS BEFORE PUTTING ANYTHING IN THE FORECAST
FOR THIS AFTERNOON. HAVE KEPT POPS JUST BELOW SLIGHT CHC FOR THE
INTERIOR FOR NOW.
BY WEDNESDAY, A DEVELOPING LOW OVER THE WESTERN GULF OF MEXICO
WILL CAUSE THE DEVELOPMENT OF A WARM FRONT ACROSS NORTH FLORIDA.
THIS WILL ALLOW FOR A SOUTHEASTERLY FLOW, WHICH WILL HAVE SOME
LIFT. THIS COULD ALLOW SOME SHOWERS TO DEVELOP ALONG THE BORDER
WITH CENTRAL FLORIDA. HAVE KEPT SLIGHT CHANCE POPS IN FOR THAT
AREA INTO THE EVENING HOURS. SPC DOES OUTLOOK THE AREA FOR A
GENERAL THUNDERSTORM, BUT THERE IS BETTER 500MB VORTICITY
ADVECTION TO THE NORTH, OVER CENTRAL FLORIDA. SO, KEPT THUNDERSTORMS
OUT OF THE FORECAST FOR WEDNESDAY AFTERNOON WITH THIS FORECAST
ISSUANCE.
THE LOW, THAT CAUSED THE WARM FRONT, WILL QUICKLY STRENGTHEN AND
MOVE NORTHEAST OVER THE FLORIDA PANHANDLE BY FRIDAY MORNING. THE
ASSOCIATED COLD FRONT WILL MAKE ITS WAY ACROSS THE GULF AND WILL
FIRST IMPACT CENTRAL FLORIDA. MODELS ARE STILL IN PRETTY GOOD
AGREEMENT WITH THE STRENGTH, PLACEMENT, AND TIMING OF THE LOW, WITH
A FEW MINOR DISCREPANCIES. THEY SHOW THE SOUTH FLORIDA COULD SEE
SOME SHOWER ACTIVITY MOVING INTO THE AREA BY 12Z FRIDAY. THERE ARE
INDICATIONS THAT A PRE-FRONTAL TROUGH WILL MOVE ACROSS THE AREA BY
18Z AND THEN THE MAIN FRONT WILL PUSH THROUGH SOMETIME AROUND 00Z
SATURDAY. THERE IS A STRONG 500MB TROUGH/LOW, DEPENDING ON WHICH
MODEL YOU LOOK AT, ASSOCIATED WITH THIS SYSTEM. THIS WILL HELP TO
DEVELOP SOME HEAVIER SHOWERS. THE MAIN QUESTION IS THE THREAT OF
THUNDERSTORMS. CURRENTLY, IT IS DIFFICULT TO TELL HOW HIGH THE
PROBABILITY OF THUNDERSTORMS WILL BE. THE REASON IS THAT THE
ATMOSPHERE COULD GET MIXED WELL BY THE PRE-FRONTAL TROUGH AND KEEP
THE SKIES CLOUDY, REDUCING DAYTIME HEATING. THIS COULD REDUCE THE
POTENTIAL, BUT DONT THINK ELIMINATE IT. HAVE KEPT HIGH CHC POPS IN
FOR FRIDAY AND EVEN MENTION A SLIGHT CHANCE FOR TSTMS LATE
THURSDAY NIGHT. IF THE ATMOSPHERE IS NOT TOO MIXED EARLY ON, THERE
COULD BE A DECENT COVERAGE OF STORMS, AND SOME OF THOSE COULD
BECOME STRONG. BUT, IT IS STILL TOO FAR OUT TOO MAKE ANY REAL
ASSUMPTIONS. SO WILL KEEP IT SIMPLE WITH A CHC OF SHOWERS AND
TSTMS FOR NOW.
BEHIND THIS FRONT, TEMPERATURES ARE NOT GOING TO BE TOO GREATLY
AFFECTED AND HIGH PRESSURE WILL BUILD IN TO BRING QUIET WEATHER
FOR THE WEEKEND AND THE BEGINNING OF NEXT WEEK. CURRENTLY LOOKING
AT MID TO UPPER 70S FOR THE COASTAL AREAS TO LOW 80S IN THE
INTERIOR PORTIONS ON SATURDAY, WITH HIGH A FEW DEGREES HIGHER ON
SUNDAY.
MARINE...
HIGH PRESSURE WILL BUILD IN TODAY. THIS WILL KEEP THE WEATHER
QUIET OVER THE GULF AND ATLANTIC WATERS FOR TODAY THROUGH TOMORROW
MORNING. AN APPROACHING SYSTEM WILL BRING A CHANCE FOR SOME
SHOWERS TO THE AREA AS EARLY AS WEDNESDAY LATE AFTERNOON.
FIRE WEATHER...
FOG IS THE MAIN FIRE WEATHER CONCERN THIS MORNING. SOME OF THE
AREAS ARE DENSE, AND MAYBE MORE SO DUE TO THE SMOKE FROM THE
HUCKABEE FIRE IN COLLIER COUNTY. CONDITIONS SHOULD IMPROVE WITHIN A
COUPLE OF HOURS AFTER SUNRISE. HIGH PRESSURE WILL BUILD IN TODAY
AND HIGH TEMPERATURES WILL FLIRT WITH 90 DEGREES IN THE INTERIOR.
THIS WILL LIKELY ALLOW A SEA BREEZE TO DEVELOP THIS AFTERNOON.
CURRENT MODELS DO SHOW THE SEA BREEZES CONVERGING OVER THE CENTRAL
PART OF THE STATE, QUITE POSSIBLY NEAR THE HUCKABEE FIRE. THIS
COULD LEAD TO BETTER INSTABILITY IN THE VICINITY OF THE FIRE.
THERE IS ALSO A SMALL POSSIBILITY OF SOME SHOWERS DEVELOPING IN
THE AREA THEY CONVERGE, BUT TOO EARLY TO TELL.
A LOW WILL BEGIN TO DEVELOP IN THE WESTERN GULF TODAY AND A WARM
FRONT WILL SET UP OVER NORTH FLORIDA. THIS COULD ALLOW SOME
SHOWERS TO BEGIN TO DEVELOP AS FAR SOUTH AS HENDRY/INTERIOR
COLLIER COUNTIES TOMORROW AFTERNOON. A COLD FRONT IS EXPECTED TO
MOVE ACROSS THE AREA FRIDAY, BRINGING SHOWERS AND POSSIBLY
THUNDERSTORMS TO THE AREA BEGINNING EARLY FRIDAY MORNING, THROUGH
FRIDAY EVENING.
PREV DISCUSSION... /ISSUED 138 AM EDT TUE APR 2 2013/
AVIATION...
FOG WAS BEGINNING TO DEVELOP ACROSS THE INTERIOR AND TOWARDS KAPF
EARLY THIS MORNING. MVFR CONDITIONS ARE EXPECTED TO DEVELOP OVER
THE NEXT FEW HOURS THROUGH 14Z. IFR CONDITIONS COULD BRIEFLY OCCUR
AT KAPF. SEA FOG IS POSSIBLE TO THE WEST OF KAPF OVER THE GULF
TODAY AS WELL. LIGHT WINDS WILL CONTINUE OVERNIGHT. SEA BREEZE
BOUNDARIES ARE EXPECTED TO DEVELOP BY EARLY AFTERNOON AT BOTH
COASTS. WINDS WILL SLOWLY DIMINISH AFTER SUNSET TO AROUND 5 KT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 81 68 80 69 / - - 10 20
FORT LAUDERDALE 82 71 81 71 / 10 - 10 0
MIAMI 83 70 81 70 / 20 - 10 0
NAPLES 80 64 81 66 / - - 10 -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS MIAMI FL
745 AM EDT TUE APR 2 2013
.UPDATE...
FOR THE SHORT TERM...DENSE FOG CONTINUES TO AFFECT MOST OF THE
SOUTH FLORIDA PENINSULA. THE ONLY TERMINALS NOT CURRENTLY AFFECTED
WITH IFR VISIBILITY RESTRICTIONS ARE KMIA AND KOPF...BUT THESE
TERMINALS COULD EXPERIENCE BRIEF PERIODS OF MIST AND/OR FOG OVER
THE NEXT HOUR OR SO WITH SUB-VFR VIS RESTRICTIONS AND WILL AMEND AS
NECESSARY. OTHERWISE...BY MID MORNING AND THROUGH THE AFTERNOON
MAINLY VFR CONDITIONS EXPECTED ALL TERMINALS. WITH LIGHT VARIABLE
FLOW THIS MORNING...THE WEST AND EAST COAST SEA BREEZES ARE
EXPECTED TO FORM TODAY.
60
&&
.PREV DISCUSSION... /ISSUED 647 AM EDT TUE APR 2 2013/
UPDATE...
SHORT TERM MODELS CONTINUE TO INDICATE THE POSSIBILITY OF AN
AFTERNOON SHOWER IN THE INTERIOR PORTION OF THE STATE LATER THIS
AFTERNOON. THE MAIN FOCUS WILL BE THE CONVERGENCE OF THE SEA
BREEZE. CONFIDENCE IS STILL LOW, BUT FEEL THERE IS ENOUGH OF A
CHANCE TO PUT A MENTION IN THE FORECAST FOR TODAY.
PREV DISCUSSION... /ISSUED 447 AM EDT TUE APR 2 2013/
DISCUSSION...
THE WEATHER FOR THE MOST PART IS QUIET. THERE IS SOME DENSE FOG IN
THE WESTERN HALF OF THE FORECAST AREA, AND SOME LOCALIZED FOG NEAR
TAMIAMI. SO, A DENSE FOG ADVISORY IS IN PLACE FOR PORTIONS OF
SOUTH FLORIDA. THIS FOG SHOULD BURN OFF WITHIN A COUPLE OF HOURS
AFTER SUNRISE.
OTHERWISE, HIGH PRESSURE IS BUILDING IN TODAY. AREAS IN THE
INTERIOR PORTIONS OF THE STATE WILL SEE HIGH TEMPERATURES IN THE
MID TO UPPER 90S. COASTAL AREAS WILL SEE HIGHS IN THE LOW TO MID
80S. THERE SHOULD BE A DECENT SEA BREEZE TO DEVELOP TODAY. WITH
SOME MOISTURE, WILL HAVE TO WATCH FOR INDICATIONS THAT SOME
SHOWERS MAY DEVELOP IN THE INTERIOR, ESPECIALLY IF THERE IS ANY
SEA BREEZE CONVERGENCE. NAM MODEL SOUNDINGS ARE SHOWING A GOOD CAP
BETWEEN 500 AND 600 MB. THE HRRR IS HINTING THAT SOMETHING MAY
DEVELOP, BUT IT IS AT THE END OF ITS MODEL RUN AND WOULD LIKE TO
SEE WHAT IT DOES WITH THIS BEFORE PUTTING ANYTHING IN THE FORECAST
FOR THIS AFTERNOON. HAVE KEPT POPS JUST BELOW SLIGHT CHC FOR THE
INTERIOR FOR NOW.
BY WEDNESDAY, A DEVELOPING LOW OVER THE WESTERN GULF OF MEXICO
WILL CAUSE THE DEVELOPMENT OF A WARM FRONT ACROSS NORTH FLORIDA.
THIS WILL ALLOW FOR A SOUTHEASTERLY FLOW, WHICH WILL HAVE SOME
LIFT. THIS COULD ALLOW SOME SHOWERS TO DEVELOP ALONG THE BORDER
WITH CENTRAL FLORIDA. HAVE KEPT SLIGHT CHANCE POPS IN FOR THAT
AREA INTO THE EVENING HOURS. SPC DOES OUTLOOK THE AREA FOR A
GENERAL THUNDERSTORM, BUT THERE IS BETTER 500MB VORTICITY
ADVECTION TO THE NORTH, OVER CENTRAL FLORIDA. SO, KEPT THUNDERSTORMS
OUT OF THE FORECAST FOR WEDNESDAY AFTERNOON WITH THIS FORECAST
ISSUANCE.
THE LOW, THAT CAUSED THE WARM FRONT, WILL QUICKLY STRENGTHEN AND
MOVE NORTHEAST OVER THE FLORIDA PANHANDLE BY FRIDAY MORNING. THE
ASSOCIATED COLD FRONT WILL MAKE ITS WAY ACROSS THE GULF AND WILL
FIRST IMPACT CENTRAL FLORIDA. MODELS ARE STILL IN PRETTY GOOD
AGREEMENT WITH THE STRENGTH, PLACEMENT, AND TIMING OF THE LOW, WITH
A FEW MINOR DISCREPANCIES. THEY SHOW THE SOUTH FLORIDA COULD SEE
SOME SHOWER ACTIVITY MOVING INTO THE AREA BY 12Z FRIDAY. THERE ARE
INDICATIONS THAT A PRE-FRONTAL TROUGH WILL MOVE ACROSS THE AREA BY
18Z AND THEN THE MAIN FRONT WILL PUSH THROUGH SOMETIME AROUND 00Z
SATURDAY. THERE IS A STRONG 500MB TROUGH/LOW, DEPENDING ON WHICH
MODEL YOU LOOK AT, ASSOCIATED WITH THIS SYSTEM. THIS WILL HELP TO
DEVELOP SOME HEAVIER SHOWERS. THE MAIN QUESTION IS THE THREAT OF
THUNDERSTORMS. CURRENTLY, IT IS DIFFICULT TO TELL HOW HIGH THE
PROBABILITY OF THUNDERSTORMS WILL BE. THE REASON IS THAT THE
ATMOSPHERE COULD GET MIXED WELL BY THE PRE-FRONTAL TROUGH AND KEEP
THE SKIES CLOUDY, REDUCING DAYTIME HEATING. THIS COULD REDUCE THE
POTENTIAL, BUT DONT THINK ELIMINATE IT. HAVE KEPT HIGH CHC POPS IN
FOR FRIDAY AND EVEN MENTION A SLIGHT CHANCE FOR TSTMS LATE
THURSDAY NIGHT. IF THE ATMOSPHERE IS NOT TOO MIXED EARLY ON, THERE
COULD BE A DECENT COVERAGE OF STORMS, AND SOME OF THOSE COULD
BECOME STRONG. BUT, IT IS STILL TOO FAR OUT TOO MAKE ANY REAL
ASSUMPTIONS. SO WILL KEEP IT SIMPLE WITH A CHC OF SHOWERS AND
TSTMS FOR NOW.
BEHIND THIS FRONT, TEMPERATURES ARE NOT GOING TO BE TOO GREATLY
AFFECTED AND HIGH PRESSURE WILL BUILD IN TO BRING QUIET WEATHER
FOR THE WEEKEND AND THE BEGINNING OF NEXT WEEK. CURRENTLY LOOKING
AT MID TO UPPER 70S FOR THE COASTAL AREAS TO LOW 80S IN THE
INTERIOR PORTIONS ON SATURDAY, WITH HIGH A FEW DEGREES HIGHER ON
SUNDAY.
MARINE...
HIGH PRESSURE WILL BUILD IN TODAY. THIS WILL KEEP THE WEATHER
QUIET OVER THE GULF AND ATLANTIC WATERS FOR TODAY THROUGH TOMORROW
MORNING. AN APPROACHING SYSTEM WILL BRING A CHANCE FOR SOME
SHOWERS TO THE AREA AS EARLY AS WEDNESDAY LATE AFTERNOON.
FIRE WEATHER...
FOG IS THE MAIN FIRE WEATHER CONCERN THIS MORNING. SOME OF THE
AREAS ARE DENSE, AND MAYBE MORE SO DUE TO THE SMOKE FROM THE
HUCKABEE FIRE IN COLLIER COUNTY. CONDITIONS SHOULD IMPROVE WITHIN A
COUPLE OF HOURS AFTER SUNRISE. HIGH PRESSURE WILL BUILD IN TODAY
AND HIGH TEMPERATURES WILL FLIRT WITH 90 DEGREES IN THE INTERIOR.
THIS WILL LIKELY ALLOW A SEA BREEZE TO DEVELOP THIS AFTERNOON.
CURRENT MODELS DO SHOW THE SEA BREEZES CONVERGING OVER THE CENTRAL
PART OF THE STATE, QUITE POSSIBLY NEAR THE HUCKABEE FIRE. THIS
COULD LEAD TO BETTER INSTABILITY IN THE VICINITY OF THE FIRE.
THERE IS ALSO A SMALL POSSIBILITY OF SOME SHOWERS DEVELOPING IN
THE AREA THEY CONVERGE, BUT TOO EARLY TO TELL.
A LOW WILL BEGIN TO DEVELOP IN THE WESTERN GULF TODAY AND A WARM
FRONT WILL SET UP OVER NORTH FLORIDA. THIS COULD ALLOW SOME
SHOWERS TO BEGIN TO DEVELOP AS FAR SOUTH AS HENDRY/INTERIOR
COLLIER COUNTIES TOMORROW AFTERNOON. A COLD FRONT IS EXPECTED TO
MOVE ACROSS THE AREA FRIDAY, BRINGING SHOWERS AND POSSIBLY
THUNDERSTORMS TO THE AREA BEGINNING EARLY FRIDAY MORNING, THROUGH
FRIDAY EVENING.
PREV DISCUSSION... /ISSUED 138 AM EDT TUE APR 2 2013/
AVIATION...
FOG WAS BEGINNING TO DEVELOP ACROSS THE INTERIOR AND TOWARDS KAPF
EARLY THIS MORNING. MVFR CONDITIONS ARE EXPECTED TO DEVELOP OVER
THE NEXT FEW HOURS THROUGH 14Z. IFR CONDITIONS COULD BRIEFLY OCCUR
AT KAPF. SEA FOG IS POSSIBLE TO THE WEST OF KAPF OVER THE GULF
TODAY AS WELL. LIGHT WINDS WILL CONTINUE OVERNIGHT. SEA BREEZE
BOUNDARIES ARE EXPECTED TO DEVELOP BY EARLY AFTERNOON AT BOTH
COASTS. WINDS WILL SLOWLY DIMINISH AFTER SUNSET TO AROUND 5 KT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 81 68 80 69 / - - 10 20
FORT LAUDERDALE 82 71 81 71 / 10 - 10 0
MIAMI 83 70 81 70 / 20 - 10 0
NAPLES 80 64 81 66 / - - 10 -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR COASTAL
COLLIER-FAR SOUTH MIAMI DADE-GLADES-HENDRY-INLAND BROWARD-
INLAND COLLIER-INLAND MIAMI DADE-INLAND PALM BEACH-MAINLAND
MONROE-METRO PALM BEACH.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS MIAMI FL
647 AM EDT TUE APR 2 2013
.UPDATE...
SHORT TERM MODELS CONTINUE TO INDICATE THE POSSIBILITY OF AN
AFTERNOON SHOWER IN THE INTERIOR PORTION OF THE STATE LATER THIS
AFTERNOON. THE MAIN FOCUS WILL BE THE CONVERGENCE OF THE SEA
BREEZE. CONFIDENCE IS STILL LOW, BUT FEEL THERE IS ENOUGH OF A
CHANCE TO PUT A MENTION IN THE FORECAST FOR TODAY.
&&
.PREV DISCUSSION... /ISSUED 447 AM EDT TUE APR 2 2013/
DISCUSSION...
THE WEATHER FOR THE MOST PART IS QUIET. THERE IS SOME DENSE FOG IN
THE WESTERN HALF OF THE FORECAST AREA, AND SOME LOCALIZED FOG NEAR
TAMIAMI. SO, A DENSE FOG ADVISORY IS IN PLACE FOR PORTIONS OF
SOUTH FLORIDA. THIS FOG SHOULD BURN OFF WITHIN A COUPLE OF HOURS
AFTER SUNRISE.
OTHERWISE, HIGH PRESSURE IS BUILDING IN TODAY. AREAS IN THE
INTERIOR PORTIONS OF THE STATE WILL SEE HIGH TEMPERATURES IN THE
MID TO UPPER 90S. COASTAL AREAS WILL SEE HIGHS IN THE LOW TO MID
80S. THERE SHOULD BE A DECENT SEA BREEZE TO DEVELOP TODAY. WITH
SOME MOISTURE, WILL HAVE TO WATCH FOR INDICATIONS THAT SOME
SHOWERS MAY DEVELOP IN THE INTERIOR, ESPECIALLY IF THERE IS ANY
SEA BREEZE CONVERGENCE. NAM MODEL SOUNDINGS ARE SHOWING A GOOD CAP
BETWEEN 500 AND 600 MB. THE HRRR IS HINTING THAT SOMETHING MAY
DEVELOP, BUT IT IS AT THE END OF ITS MODEL RUN AND WOULD LIKE TO
SEE WHAT IT DOES WITH THIS BEFORE PUTTING ANYTHING IN THE FORECAST
FOR THIS AFTERNOON. HAVE KEPT POPS JUST BELOW SLIGHT CHC FOR THE
INTERIOR FOR NOW.
BY WEDNESDAY, A DEVELOPING LOW OVER THE WESTERN GULF OF MEXICO
WILL CAUSE THE DEVELOPMENT OF A WARM FRONT ACROSS NORTH FLORIDA.
THIS WILL ALLOW FOR A SOUTHEASTERLY FLOW, WHICH WILL HAVE SOME
LIFT. THIS COULD ALLOW SOME SHOWERS TO DEVELOP ALONG THE BORDER
WITH CENTRAL FLORIDA. HAVE KEPT SLIGHT CHANCE POPS IN FOR THAT
AREA INTO THE EVENING HOURS. SPC DOES OUTLOOK THE AREA FOR A
GENERAL THUNDERSTORM, BUT THERE IS BETTER 500MB VORTICITY
ADVECTION TO THE NORTH, OVER CENTRAL FLORIDA. SO, KEPT THUNDERSTORMS
OUT OF THE FORECAST FOR WEDNESDAY AFTERNOON WITH THIS FORECAST
ISSUANCE.
THE LOW, THAT CAUSED THE WARM FRONT, WILL QUICKLY STRENGTHEN AND
MOVE NORTHEAST OVER THE FLORIDA PANHANDLE BY FRIDAY MORNING. THE
ASSOCIATED COLD FRONT WILL MAKE ITS WAY ACROSS THE GULF AND WILL
FIRST IMPACT CENTRAL FLORIDA. MODELS ARE STILL IN PRETTY GOOD
AGREEMENT WITH THE STRENGTH, PLACEMENT, AND TIMING OF THE LOW, WITH
A FEW MINOR DISCREPANCIES. THEY SHOW THE SOUTH FLORIDA COULD SEE
SOME SHOWER ACTIVITY MOVING INTO THE AREA BY 12Z FRIDAY. THERE ARE
INDICATIONS THAT A PRE-FRONTAL TROUGH WILL MOVE ACROSS THE AREA BY
18Z AND THEN THE MAIN FRONT WILL PUSH THROUGH SOMETIME AROUND 00Z
SATURDAY. THERE IS A STRONG 500MB TROUGH/LOW, DEPENDING ON WHICH
MODEL YOU LOOK AT, ASSOCIATED WITH THIS SYSTEM. THIS WILL HELP TO
DEVELOP SOME HEAVIER SHOWERS. THE MAIN QUESTION IS THE THREAT OF
THUNDERSTORMS. CURRENTLY, IT IS DIFFICULT TO TELL HOW HIGH THE
PROBABILITY OF THUNDERSTORMS WILL BE. THE REASON IS THAT THE
ATMOSPHERE COULD GET MIXED WELL BY THE PRE-FRONTAL TROUGH AND KEEP
THE SKIES CLOUDY, REDUCING DAYTIME HEATING. THIS COULD REDUCE THE
POTENTIAL, BUT DONT THINK ELIMINATE IT. HAVE KEPT HIGH CHC POPS IN
FOR FRIDAY AND EVEN MENTION A SLIGHT CHANCE FOR TSTMS LATE
THURSDAY NIGHT. IF THE ATMOSPHERE IS NOT TOO MIXED EARLY ON, THERE
COULD BE A DECENT COVERAGE OF STORMS, AND SOME OF THOSE COULD
BECOME STRONG. BUT, IT IS STILL TOO FAR OUT TOO MAKE ANY REAL
ASSUMPTIONS. SO WILL KEEP IT SIMPLE WITH A CHC OF SHOWERS AND
TSTMS FOR NOW.
BEHIND THIS FRONT, TEMPERATURES ARE NOT GOING TO BE TOO GREATLY
AFFECTED AND HIGH PRESSURE WILL BUILD IN TO BRING QUIET WEATHER
FOR THE WEEKEND AND THE BEGINNING OF NEXT WEEK. CURRENTLY LOOKING
AT MID TO UPPER 70S FOR THE COASTAL AREAS TO LOW 80S IN THE
INTERIOR PORTIONS ON SATURDAY, WITH HIGH A FEW DEGREES HIGHER ON
SUNDAY.
MARINE...
HIGH PRESSURE WILL BUILD IN TODAY. THIS WILL KEEP THE WEATHER
QUIET OVER THE GULF AND ATLANTIC WATERS FOR TODAY THROUGH TOMORROW
MORNING. AN APPROACHING SYSTEM WILL BRING A CHANCE FOR SOME
SHOWERS TO THE AREA AS EARLY AS WEDNESDAY LATE AFTERNOON.
FIRE WEATHER...
FOG IS THE MAIN FIRE WEATHER CONCERN THIS MORNING. SOME OF THE
AREAS ARE DENSE, AND MAYBE MORE SO DUE TO THE SMOKE FROM THE
HUCKABEE FIRE IN COLLIER COUNTY. CONDITIONS SHOULD IMPROVE WITHIN A
COUPLE OF HOURS AFTER SUNRISE. HIGH PRESSURE WILL BUILD IN TODAY
AND HIGH TEMPERATURES WILL FLIRT WITH 90 DEGREES IN THE INTERIOR.
THIS WILL LIKELY ALLOW A SEA BREEZE TO DEVELOP THIS AFTERNOON.
CURRENT MODELS DO SHOW THE SEA BREEZES CONVERGING OVER THE CENTRAL
PART OF THE STATE, QUITE POSSIBLY NEAR THE HUCKABEE FIRE. THIS
COULD LEAD TO BETTER INSTABILITY IN THE VICINITY OF THE FIRE.
THERE IS ALSO A SMALL POSSIBILITY OF SOME SHOWERS DEVELOPING IN
THE AREA THEY CONVERGE, BUT TOO EARLY TO TELL.
A LOW WILL BEGIN TO DEVELOP IN THE WESTERN GULF TODAY AND A WARM
FRONT WILL SET UP OVER NORTH FLORIDA. THIS COULD ALLOW SOME
SHOWERS TO BEGIN TO DEVELOP AS FAR SOUTH AS HENDRY/INTERIOR
COLLIER COUNTIES TOMORROW AFTERNOON. A COLD FRONT IS EXPECTED TO
MOVE ACROSS THE AREA FRIDAY, BRINGING SHOWERS AND POSSIBLY
THUNDERSTORMS TO THE AREA BEGINNING EARLY FRIDAY MORNING, THROUGH
FRIDAY EVENING.
PREV DISCUSSION... /ISSUED 138 AM EDT TUE APR 2 2013/
AVIATION...
FOG WAS BEGINNING TO DEVELOP ACROSS THE INTERIOR AND TOWARDS KAPF
EARLY THIS MORNING. MVFR CONDITIONS ARE EXPECTED TO DEVELOP OVER
THE NEXT FEW HOURS THROUGH 14Z. IFR CONDITIONS COULD BRIEFLY OCCUR
AT KAPF. SEA FOG IS POSSIBLE TO THE WEST OF KAPF OVER THE GULF
TODAY AS WELL. LIGHT WINDS WILL CONTINUE OVERNIGHT. SEA BREEZE
BOUNDARIES ARE EXPECTED TO DEVELOP BY EARLY AFTERNOON AT BOTH
COASTS. WINDS WILL SLOWLY DIMINISH AFTER SUNSET TO AROUND 5 KT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 81 68 80 69 / - - 10 20
FORT LAUDERDALE 82 71 81 71 / 10 - 10 0
MIAMI 83 70 81 70 / 20 - 10 0
NAPLES 80 64 81 66 / - - 10 -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR COASTAL
COLLIER-FAR SOUTH MIAMI DADE-GLADES-HENDRY-INLAND BROWARD-
INLAND COLLIER-INLAND MIAMI DADE-INLAND PALM BEACH-MAINLAND
MONROE-METRO PALM BEACH.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...13/SI
AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION
NWS CARIBOU ME
627 AM EDT TUE APR 2 2013
.SYNOPSIS...
A COLD AIR MASS WILL REMAIN IN PLACE ACROSS THE REGION THROUGH
WEDNESDAY. DISTURBANCES ROTATING AROUND AN EASTERN CANADIAN LOW
WILL PRODUCE SNOW SHOWERS ACROSS NORTHERN AND WESTERN MAINE TODAY
INTO TONIGHT THAT WILL BECOME SCATTERED WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
0615AM UPDATE...
VERY DRY AIR IS WORKING SOUTHWARD THROUGH THE FORECAST AREA THIS
MORNING. ADJUSTED DEW POINTS DOWN AND WIND GUSTS UP IN LATEST
UPDATE. ALSO ADDED CHANCE POPS FOR SNOW SHOWERS FOR BANGOR BY
MIDDAY AS HRRR AND RUC ARE SHOWING A WEAK SURFACE TROUGH MOVING
ACROSS THE AREA EARLY THIS AFTERNOON. ANOTHER TROUGH APPEARS IN
NORTHERN MAINE LATE THIS AFTERNOON WITH THE CHANCE OF SOME
BRIEF...HEAVIER SNOW SHOWERS IN AROOSTOOK. OTHERWISE...EXPECT A
LOT OF WEAKER SNOW SHOWERS POPPING UP ACROSS THE FORECAST AREA
THIS AFTERNOON.
A COLD UPPER LOW WILL MOVE JUST NORTH OF THE FORECAST AREA THIS
AFTERNOON. COLD AIR ALOFT COMBINED WITH H850 MOISTURE WILL PRODUCE
INSTABILITY TO NEAR H700 THIS AFTERNOON AND EVENING. THE RESULTING
SNOW SHOWERS WILL BE MOST LIKELY IN THE CROWN OF MAINE...BUT A FEW
SHOWERS WILL OCCUR ALL THE WAY SOUTH TO THE COAST THIS AFTERNOON.
THE MIXING ASSOCIATED WITH THIS INSTABILITY WILL PRODUCE A WINDY
DAY WITH WEST WINDS GUSTING TO OVER 30 MPH. THE WELL MIXED
ATMOSPHERE WILL PRODUCE A MIXTURE OF SUN AND CLOUDS BUT WILL GO
WITH MOSTLY CLOUDY IN MOST ZONES THIS AFTERNOON. SOME LOCATIONS
MAY RECEIVE MULTIPLE SNOW SHOWERS DURING THE COURSE OF THE
AFTERNOON. TEMPERATURES WILL ONLY REACH THE UPPER 20S NORTH AND
LOW 30S FOR BANGOR AND DOWN EAST. THE SNOW SHOWERS WILL CONTINUE
INTO THE EVENING AND THEN SUBSIDENCE ALOFT WILL CREATE
STRATOCUMULUS TONIGHT. THESE CLOUDS AND CONTINUED WINDS WILL ONLY
ALLOW TEMPERATURES TO FALL TO THE MID TO UPPER TEENS NORTH AND LOW
20S FOR BANGOR AND DOWN EAST ZONES.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
A DEEP UPPER LOW ACROSS ERN CANADA WILL ROTATE OUT TO THE
NW AND BEGIN TO GRADUALLY LOOSE ITS GRIP ON THE WEATHER ACROSS
NRN NEW ENGLAND. THE AIR MASS WILL CONTINUE TO BE UNSEASONABLY
COLD WITH AN 850 MB TEMP OF AROUND -17C AT 12Z WED WHICH IS ABOUT
2 STD DEV BELOW NORMAL FOR EARLY APR. THERE WILL STILL BE ENOUGH
CYCLONIC FLOW ALOFT WHICH IS CONDUCIVE FOR MOISTURE AND WEAK
DISTURBANCES TO ROTATE THROUGH AND PRODUCE SCATTERED SNOW SHOWERS
ACROSS THE WESTERN MOUNTAINS AND FAR NORTHERN MAINE...ESPECIALLY
SO ACROSS THE FAVORED UPSLOPE AREAS. TEMPS WILL REMAIN ABOUT 10
DEGREES BELOW NORMAL WITH HIGHS ONLY IN THE UPPER 20S TO LOW 30S
NORTH WITH M/U 30S DOWNEAST. A SFC HIGH SLIDES SOUTH OF THE AREA
THU AS A WEAK CLIPPER APPROACHES FROM THE WEST LATE IN THE DAY.
TEMPERATURES THU PM WILL MODERATE BACK CLOSER TO 40 IN THE NORTH
AND MID 40S DOWNEAST. CLOUDS WILL INCREASE ACROSS THE NORTH AHEAD
OF THE CLIPPER SYSTEM.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A WEAK FRONTAL BOUNDARY ASSOCIATED WITH THE AFORE MENTIONED
CLIPPER WASHES OUT ACROSS THE AREA FRI AS ATTENTION TURNS TO A
SOUTHERN BRANCH LOW THAT MOVES OFF THE MID ATLANTIC COAST FRI
PM. THE ECMWF HAS BEEN CONSISTENT IN HAVING A WEAKER AND LESS
PHASED SYSTEM THAT PASSES FAR ENOUGH SOUTH OF THE AREA TO KEEP THE
PRECIPITATION SHIED WELL OFFSHORE. THE GFS AND CANADIAN HAVE
STRONGER AND MORE PHASED SOLUTIONS THAT WOULD BRING SOME RAIN OR
MIXED PRECIPITATION CHANGING TO SNOW FOR DOWNEAST AREAS FRI NIGHT.
THE 00Z RUNS OF THE GFS AND CANADIAN ARE A BIT FURTHER EAST WITH
THE LOW WHEN COMPARED TO LAST NIGHTS RUNS. THE ONGOING FORECAST
HAS THIS COVERED WELL WITH HIGH CHANCE POPS DOWNEAST FRI NIGHT. A
RIDGE OF HIGH PRESSURE BRIEFLY BUILDS IN FROM THE WEST SAT AND IS
QUICKLY FOLLOWED BY ANOTHER WEAK CLIPPER THAT MOVES IN FROM THE
WEST SAT NIGHT AND SUN. YET ANOTHER SYSTEM APPROACHES FROM THE
WEST/SOUTHWEST LATE MON WITH THE POTENTIAL FOR ANOTHER MIXED
PRECIPITATION EVENT.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: MVFR CIGS EARLY THIS MORNING NORTH OF HOULTON. THESE
CIGS WILL RISE TOWARDS 5000FT THIS AFTERNOON WITH WIDESPREAD SNOW
SHOWERS UP TO 10000FT. STRONG WIND GUSTS AS HIGH AS 35 MPH ARE
EXPECTED THIS AFTERNOON WITH A LOT OF LOW LEVEL TURBULENCE. VIS IN
SNOW SHOWERS COULD DROP BRIEFLY TO IFR THIS AFTERNOON.
SHORT TERM: MVFR AT TIMES AT THE NORTHERN TERMINALS INTO WED
EVENING IN SCT -SHSN. OTHERWISE VFR THROUGH THU NIGHT. MVFR
POSSIBLE FRI IN SCT -SHSN/SHRA. A COASTAL STORM MAY LOWER
CONDITIONS TO IFR FRI NIGHT IN RN/SN AT KBHB AND KBGR.
&&
.MARINE...
NEAR TERM: SCA WILL CONTINUE WITH STRONG WEST WINDS GUSTING TO 35
KT AND SEAS IN THE SIX TO EIGHT FOOT RANGE.
SHORT TERM: THE SCA WAS EXTENDED THROUGH 6 PM WED...AND SUBSEQUENT
SHIFTS WILL LIKELY NEED TO EXTEND IT ONE MORE FORECAST PERIOD
THROUGH WED NIGHT. THE WIND MAY DROP OFF FOR A TIME THU...BUT IS
EXPECTED TO PICK UP AGAIN LATE IN THE DAY AHEAD OF AN APPROACHING
FRONTAL BOUNDARY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT WEDNESDAY FOR ANZ050>052.
&&
$$
NEAR TERM...MCW
SHORT TERM...CB
LONG TERM...CB
AVIATION...MCW
MARINE...MCW/CB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
731 AM EDT TUE APR 2 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EDT TUE APR 2 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF OVER
THE E HALF OF NAMERICA DOWNSTREAM OF RDG OVER WRN CANADA. CWA
REMAINS DOMINATED BY COLD CYC NW FLOW IN THE WAKE OF SLOWLY
DEPARTING CLOSED LO OVER WRN QUEBEC. ALTHOUGH H85 TEMPS RANGING FM
-14C OVER THE W TO -16C OVER THE E AND INVRN BASE NEAR H8 ARE
SUFFICIENTLY COLD/HI FOR LES EVEN IN THE ABSENCE OF ANY DYNAMIC
FORCING...UPSTREAM 00Z INL/YPL RAOBS ARE SO DRY...WITH THE H925
DEWPT DEPRESSION 15C AT INL IN INVERTED V T/TD PROFILE...THAT THERE
ONLY A FEW WEAK CLD BANDS OVER THE W HALF OF LK SUP STREAMING INTO
THE WRN ZNS. WITH A LONGER FETCH OVER THE E HALF AND A WEAK SFC TROF
PASSING THRU THIS AREA...MORE CLDS/SOME LES BANDS ARE EVIDENT
STREAMING INTO THE CWA E OF MQT. BUT DRYNESS OF AIRMASS IS EVIDENT
IN LO REFLECTIVITIES. LOOKING FARTHER UPSTREAM...THERE IS A FAIRLY
VIGOROUS SHRTWV NEAR LK WINNIPEG DIGGING SEWD. BUT SINCE THE 00Z THE
PAS MANITOBA RAOB IS ALSO QUITE DRY WITH INVERTED V T/TD PROFILE IN
THE LLVLS...THERE ARE ONLY SOME PATCHY MID/HI CLDS IN THE PVA
ASSOCIATED WITH THIS FEATURE. ANOTHER SHRTWV OVER HUDSON BAY IS
DIVING SWD.
EARLY THIS MRNG/TODAY...WITH NOCTURNAL COOLING EARLY THIS MRNG AND
SOME ENHANCED LLVL CNVGC ALONG WEAK SFC TROF...EXPECT SCT-NMRS -SHSN
TO IMPACT THE ERN ZNS THRU THIS MRNG. OVER THE W...THERE SHOULD BE
LTL IF ANY LES OR EVEN LK CLDS THRU 09Z GIVEN THE UPSTREAM
DRYNESS...BUT MODELS SHOW AREA OF DPVA/H85-5 QVECTOR CNVGC
ASSOCIATED WITH SHRTWV DIGGING THRU MN IMPACTING THE FAR W BY 12Z.
SUSPECT MORE CLDS/A FEW -SHSN MIGHT DVLP IN PRESENCE OF NOCTURNAL
COOLING...BUT LLVL DRYNESS WL LIMIT COVERAGE/INTENSITY OF ANY SHSN
THAT MIGHT POP UP. IF THERE IS ANY SHSN...THESE SHOULD DIMINISH ONCE
THE FORCING PASSES TO THE S BY 15Z AND DAYTIME HEATING BEGINS TO
DISRUPT THE LES PROCESS. LATE IN THE DAY...NEXT SHRTWV OVER HUDSON
BAY IS PROGGED TO DIG INTO THE UPR LKS WITH ACCOMPANYING DPVA AND
H85-5 QVECTOR CNVGC IMPACTING THE CWA. ALTHOUGH DAYTIME HEATING
MIGHT ALSO DISRUPT THE LES OVER THE E HALF IN THE AFTN...THE ARRIVAL
OF THIS FORCING MIGHT CAUSE AN UPTICK OF SHSN AGAIN TOWARD 00Z
ESPECIALLY OVER THE E HALF CLOSER TO DEEPER MSTR/COLDER AIR.
AS FOR TEMPS...PREFER TO TEND TOWARD THE HIER END OF GUIDANCE WITH A
GOOD DEAL OF SUNSHINE...AT LEAST OVER THE W AND SCENTRAL.
TNGT...SHRTWV DROPPING S INTO THE UPR LKS AND ACCOMPANYING DYNAMIC
FORCING IS PROGGED TO CROSS THE ERN COUNTIES. WITH LOWER H85 TEMPS
ARND -17C CLOSER TO THE CYC SIDE OF THE TRACK OF THIS DISTURBANCE AS
WELL AS DEEPER MSTR/SOMEWHAT HIER INVRN SHOWN THERE ON FCST SDNGS...
OPTED TO RAISE POPS INTO THE LIKELY RANGE NEAR LK SUP E OF MQT AS
THESE EVENTS OCCUR DURING THE MORE FAVORABLE NOCTURNAL COOLING.
EXPECT MUCH LESS IF ANY ACTIVITY OVER THE W ON THE ACYC SIDE OF THE
SHRTWV PASSAGE AND WHERE FCST SNDGS SHOW MUCH DRIER AIR AND HIER H85
TEMPS/LOWER INVNR BASE. EXPECT THE LOWEST MIN TEMPS TOWARD THE LOWER
END OF GUIDANCE OVER THE INTERIOR W UNDER THE DRIER AIR AND WHERE
WINDS WL BE LIGHTER.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 520 AM EDT TUE APR 2 2013
LOOKS LIKE A PATTERN CHANGE IS IN THE OFFING OVER THE NEXT FEW WEEKS
THAT WILL TRANSITION THE PERSISTENT BELOW NORMAL TEMP REGIME TOWARD
AN ABOVE NORMAL ONE. THE AO AND NAO WHICH HAVE BEEN IN A PREVAILING
NEGATIVE PHASE SINCE EARLY/MID FEB ARE BOTH FORECAST TO TREND TO THE
POSITIVE PHASE...WITH THE AO BECOMING STRONGLY POSITIVE. THIS
SUPPORTS A TREND TOWARD ABOVE NORMAL TEMPS HEADING INTO MID/LATE
APRIL...BUT THIS DOESN`T PRECLUDE THE POTENTIAL FOR MORE WINTRY PCPN
EVENTS BEFORE THE WARMER PATTERN SETS IN. THE PATTERN ALSO APPEARS
TO BE SHIFTING TOWARD AN ACTIVE ONE OVER THE NEXT 2 WEEKS. INTO THE
UPCOMING WEEKEND...FLOW WILL TREND PROGRESSIVE AND FLATTER WITH A
COUPLE OF SHORTWAVES TO AFFECT THE UPPER LAKES...THE FIRST WED
NIGHT/THU AND A SECOND MORE IMPORTANT WAVE SAT. EARLY NEXT WEEK...AN
AMPLIFIED TROF WILL BE DEVELOPING OVER THE WRN CONUS...SIGNALING THE
POTENTIAL FOR MORE SIGNIFICANT PCPN EVENTS NEXT WEEK FROM THE
CNTRL/SRN PLAINS TO THE GREAT LAKES AS THE GULF OPENS UP. THIS COULD
MEAN ONE OR MORE UNWELCOMED RAIN EVENTS ON A MELTING SNOWPACK WHICH
IS STILL DEEP IN THE LAKE EFFECT AREAS OR MORE SNOW COULD STILL BE
ADDED. IN RECENT DAYS...MEDIUM RANGE GUIDANCE HAS TONED DOWN THE
WARMING NEXT WEEK...SO MORE SNOW IS STILL A REAL POSSIBILITY.
BEGINNING WED...SFC HIGH PRES WILL QUICKLY SHIFT ACROSS THE WRN
GREAT LAKES AHEAD OF THE FIRST SHORTWAVE THAT WILL BE TRACKING
ACROSS SASKATCHEWAN/MANITOBA. IF ANY LIGHT LES IS LINGERING OVER THE
ERN FCST AREA TO START THE DAY...IT WILL END QUICKLY IN THE MORNING.
AFTER A PERIOD OF SUNSHINE...HIGH CLOUDS WILL BE ON THE INCREASE.
SUNSHINE WILL SUPPORT A STRONG DIURNAL TEMP SPREAD. AFTER MORNING
LOWS IN THE SINGLE DIGITS OVER THE INTERIOR W...TEMPS SHOULD REBOUND
INTO THE UPPER 30S/LWR 40S.
SHORTWAVE WILL MOVE ACROSS NRN ONTARIO WED NIGHT/THU MORNING. WITH
STRONG DEEP LAYER FORCING/IMPRESSIVE 500MB HEIGHT FALLS (AROUND
200M/12HR) PASSING WELL TO THE N OF HERE...MAIN PCPN AREA WILL PASS
TO THE N OF UPPER MI. NONETHELESS...50-80M HEIGHT FALLS AT 500MB...
RIBBON OF MODEST DEEP LAYER FORCING PER QVECTORS AND ISENTROPIC
ASCENT SUGGEST SOME PCPN POTENTIAL ACROSS THE FCST AREA. WITH
ISENTROPIC ASCENT WEAKENING AS IT SHIFTS ACROSS THE UPPER LAKES...
AND LOW-LEVEL DRY AIR TO OVERCOME INITIALLY...NOTHING MORE THAN LOW
CHC POPS APPEAR WARRANTED ATTM. ALTHOUGH LOW-LEVEL TEMPS ARE JUST
ABOVE 0C PRIOR TO POTENTIAL PCPN ARRIVING...EVAPORATIVE COOLING
SHOULD BE SUFFICIENT SO THAT SNOW BECOMES THE MAIN PTYPE IN MOST
AREAS. PCPN CHC WILL END W TO E THU MORNING WITH DRY WEATHER
FOLLOWING THRU THU NIGHT/FRI AS SFC HIGH PRES RIDGE BUILDS SE INTO
THE UPPER LAKES. 850MB TEMPS FALLING TO AROUND -12C THU NIGHT/FRI
MORNING WILL BE AT THE THRESHOLD FOR LES. HOWEVER...SINCE LOW-LEVEL
FLOW BECOMES MORE ANTICYCLONIC DURING THE NIGHT AND AIR MASS IS
FAIRLY DRY IN THE LOW-LEVELS...WILL NOT INCLUDE ANY MENTION OF
-SHSN. OVER THE W...FLOW IS MORE DIVERGENT...SO THERE MAY NOT EVEN
BE MUCH IN THE WAY OF CLOUDS. OPTED TO GO BLO GUIDANCE THERE THU
NIGHT AS WINDS WILL PROBABLY FALL OFF TO CALM AS HIGH PRES RIDGE
NEARS. ALTHOUGH LOWERED MINS TO THE LOW/MID TEENS...TEMPS COULD
EASILY FALL INTO THE SINGLE DIGITS.
FRI NIGHT/SAT...ATTENTION TURNS TO THE SECOND MORE IMPORTANT
SHORTWAVE TRACKING ACROSS THE NRN CONUS IN FLATTER FLOW REGIME.
MEDIUM RANGE GUIDANCE IS MOVING TOWARD SLIGHTLY BETTER AGREEMENT
WITH SYSTEM...BUT IMPORTANT DETAILS HAVE YET TO BE NARROWED DOWN.
THE GFS WHICH HAS BEEN CONSISTENTLY FARTHER S HAS TRENDED A LITTLE
FARTHER N WITH WAVE AND IS IN DECENT AGREEMENT WITH THE GLOBAL GEM.
THE ECMWF HAS BEEN CONSISTENTLY FARTHER N. THE GFS TRACK LOOKS TO
SUPPORT ALL SNOW FOR THE FCST AREA AS THE 850MB LOW TRACKS ALONG
WI/UPPER MI BORDER AND 850MB TEMPS REMAIN BLO 0C AND 1000-850MB
THICKNESS IS NO HIGHER THAN 1295M. THE GLOBAL GEM MOSTLY SUPPORTS
ALL SNOW WITH A POSSIBLE CHANGEOVER TO RAIN S AND SE...BUT ITS
SLOWER/MORE WRAPPED UP SYSTEM DOES NOT APPEAR TO FIT THE DEVELOPING
FLATTER FLOW REGIME. HOWEVER...THE 00Z ECMWF ALSO TRENDED MUCH
SLOWER AND SHARPER WITH SHORTWAVE...SO THIS MAY BE AN IMPORTANT
TREND TO MONITOR IN FUTURE MODEL RUNS. THE FARTHER N ECMWF SUGGESTS
MORE OF A MIXED PCPN EVENT WITH MORE SNOW THAN RAIN N AND MORE RAIN
THAN SNOW S. THE HEAVIEST SWATH OF PCPN PASSES ACROSS NRN UPPER MI
IN THE ECMWF...JUST S IN THE GFS AND CLIPS THE SRN FCST AREA IN THE
GLOBAL GEM. WHILE THE DETAILS OF SHORTWAVE TRACK...RESULTING PCPN
AREA AND THE ALL IMPORTANT TEMP PROFILE HAVE YET TO BE AGREED
UPON...WHAT IS A LITTLE MORE CERTAIN IS THAT THIS WAVE MAY BE A
RATHER IMPRESSIVE PCPN PRODUCER DESPITE THE FLATTER FLOW REGIME.
STRONG WAA IS NOTED BY ALL GUIDANCE WITH 850MB WINDS AROUND 50KT.
THE FRONTOGENESIS SIGNAL IS ALSO QUITE STRONG. PROXIMITY OF STEEP
MIDLEVEL LAPSE RATES NEAR THE SRN EDGE OF THE PCPN AREA SUGGESTS
THERE WILL PROBABLY BE SOME CONVECTION AS IS OFTEN SEEN WITH WAVES
RUNNING ALONG THE BAROCLINIC ZONE AT THIS TIME OF YEAR. IT WILL BE A
SYSTEM TO WATCH.
IN THE WAKE OF THE SAT SYSTEM...DRY WEATHER SHOULD FOLLOW FOR SUN
UNDER WEAK SFC HIGH PRES RIDGE...THOUGH IF THE SLOWER GLOBAL GEM AND
ECMWF ARE RIGHT...SOME PCPN COULD LINGER THRU AT LEAST PART OF SUN.
ATTENTION THEN TURNS TO THE SW FOR MON/TUE AS TROF AMPLIFIES INTO
THE WRN CONUS. AMPLIFYING TROF MAY SEND SEVERAL SHORTWAVES INTO THE
GREAT LAKES NEXT WEEK WITH THE FIRST PERHAPS AS SOON AS MON. AS
WOULD BE EXPECTED WITH A DEEPENING WRN TROF...MODELS ARE AND WILL
CONTINUE TO HAVE TROUBLE WITH TIMING AND PLACEMENT OF SHORTWAVES
EJECTING NE...SO THERE IS LITTLE CONFIDENCE RIGHT NOW IN THE PCPN
FCST MON/TUE. WITH GULF OPENING UP AHEAD OF THE LARGE SCALE WRN
TROF...ANY SHORTWAVES AFFECTING THE AREA COULD BE MDT/HVY PCPN
PRODUCERS NEXT WEEK...AND PCPN COULD BE SNOW FOR PORTIONS OF UPPER
MI.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 730 AM EDT TUE APR 2 2013
ALTHOUGH A LO PRES TROF WILL PASS THIS EVNG...EXPECT VFR CONDITIONS
AT THE TAF SITES THIS PERIOD WITH DRY LLVL AIR. WITH DAYTIME
HEATING...THERE WL BE A GUSTY NW WIND MUCH OF TODAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 520 AM EDT TUE APR 2 2013
WHERE THE PRES GRADIENT WILL BE SHARPER CLOSER TO DEPARTING LO PRES
IN SE CANADA...EXPECT NNW WINDS UP TO 30 KTS THRU TONIGHT OVER THE E
ALONG WITH FREEZING SPRAY. LIGHTER WINDS UP TO 20 KTS WILL PREVAIL
OVER THE W WHERE THE GRADIENT WILL BE WEAKER. AFTER A BRIEF PERIOD
OF LIGHT WINDS FOR A PORTION OF WED AS HIGH PRES QUICKLY PASSES...S
TO SW WINDS WILL QUICKLY RAMP UP TO 20-30KT WED AFTN/EVENING AHEAD OF
LOW PRES TRACKING E INTO NRN ONTARIO. ALTHOUGH LOW-LEVEL TEMP PROFILE
IS STABLE...HEALTHLY PRES FALLS PASSING ACROSS NRN ONTARIO SUGGEST
THERE WILL BE SOME POTENTIAL FOR A SHORT PERIOD OF GALES WED NIGHT.
WINDS SHIFT WNW FOR THU. WHILE WINDS WILL DIMINISH TO 15-25KT OVER
THE W...20-30KT WINDS WILL CONTINUE OVER THE E. WINDS WILL THEN
DIMINISH TO LIGHT (UNDER 15KT) FRI HAS HIGH PRES RIDGE ARRIVES. WINDS
SHOULD REMAIN UNDER 20KT SAT...BUT WITH UNCERTAINTY IN THE
STRENGTH/TRACK OF NEXT LOW PRES TRACKING E INTO THE GREAT LAKES...
WINDS COULD END UP STRONGER THAN CURRENTLY FCST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...ROLFSON
AVIATION...KC
MARINE...KC/ROLFSON
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
620 AM CDT TUE APR 2 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 316 AM CDT TUE APR 2 2013
TODAY...THE HIGH PLAINS DISTURBANCE OPERATING ON LIMITED
MOISTURE WILL DRIFT VERY SLOWLY EAST SOUTHEAST TODAY AND TONIGHT.
GIVEN THE DRY AIR AT THE LOWER LEVELS...SPRINKLES LOOKED REASONABLE
ACROSS SWRN NEB. MID LEVEL CLOUDINESS WILL HANG ON TODAY AND TONIGHT
ACROSS THE SOUTHWEST. ELSEWHERE...MOSTLY CLEAR. A WEAK AREA FOR
FRONTOGENESIS HAS DEVELOPED ACROSS THE MISSOURI BASIN. THE RAP MODEL
IS LIFTING THIS FEATURE UP INTO THE MIDWEST TODAY.
OTHERWISE...A WARM FRONT SHOULD LIFT NORTH INTO THE SANDHILLS TODAY
WHILE WINDS NORTH OF THE FRONT BACK TO THE EAST AND NORTHEAST. FULL
SUN IN MANY AREAS SHOULD SEND HIGHS TO AROUND 60. THE RAP SUGGESTED
LOWER 60S IN MANY AREAS BUT THAT MODEL TENDS TO RUN WARM. RH DROPS
TO 20 TO 25 PERCENT THIS AFTERNOON BUT WINDS SHOULD REMAIN BELOW 15
MPH WITH WEAK WINDS CARRYING ALL THE WAY TO 700 MB.
TONIGHT...LOW PRESSURE DEVELOPS ACROSS THE NRN HIGH PLAINS WHICH
SETS UP A STRONGER SOUTHWEST WIND TONIGHT. THIS WILL HOLD LOWS
AROUND FREEZING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 316 AM CDT TUE APR 2 2013
12Z WEDNESDAY AND BEYOND. MAIN FORECAST CONCERN GOING
IN THE EXTENDED PERIOD REVOLVES AROUND THE DEVELOPMENT OF AN
AMPLIFIED WESTERN CONUS TROUGH...WHICH MAY BRING PERIODS OF
WIDESPREAD PRECIPITATION BACK ACROSS THE CWA THIS WEEKEND AND
ESPECIALLY EARLY NEXT WEEK. BUT FIRST...AN UPPER LOW AND ATTENDANT
TROUGH THAT WILL BE POSITIONED ACROSS SOUTHEAST COLORADO/NORTHERN
NEW MEXICO EARLY WEDNESDAY WILL PROGRESS SOUTHEAST ACROSS TEXAS AND
THE SOUTHERN PLAINS THROUGH THURSDAY. THIS WILL ALLOW A TRANSITION
FROM SPLIT FLOW ALOFT OVER THE CENTRAL PLAINS...TO NORTHWESTERLY...AND
EVENTUALLY SOUTHWESTERLY AS A UPPER RIDGE BUILDS ACROSS THE PLAINS
ON FRIDAY. AT THE SAME TIME...AN UPPER TROUGH AND ATTENDANT LOW
WILL BE RAPIDLY PROGRESSING ACROSS THE CANADIAN ROCKIES TOWARD
SOUTHERN ONTARIO...DRAGGING A COLD FRONT THROUGH THE
NORTHERN/CENTRAL HIGH PLAINS EARLY ON THURSDAY. TEMPERATURES ON
WEDNESDAY WILL BE ATYPICAL...WITH THE WARMEST READINGS ACROSS
NORTHERN NEBRASKA...WHERE HIGHS IN THE LOW TO MID 60S SHOULD
PREVAIL. FOR SOUTHERN NEBRASKA...HIGHS ON WEDNESDAY WILL BE SOME
5-8F COOLER AS THE INFLUENCE OF THE SOUTHERN PLAINS UPPER LOW SHOULD
ALLOW FOR AN INCREASE CLOUDINESS AND SLIGHTLY COOLER TEMPERATURES
ALOFT. SLIGHTLY COOLER ACROSS THE NORTH ON THURSDAY AS MODIFIED
ARCTIC HIGH PRESSURE RECYCLES SOME COOLER AIR BACK INTO NORTH
CENTRAL NEBRASKA...ANTICIPATING HIGHS MAINLY IN THE MID 50S.
TEMPERATURES ACROSS THE SOUTH AND WEST WILL WARM SEVERAL DEGREES
UNDER FULL SUN AND WEAK WARMING ALOFT...MID 60S SHOULD PREVAIL.
FRIDAY WILL BE THE WARMEST DAY OF THE WEAK FOR ALL AREAS AS THE
UPPER RIDGE AXIS SHIFTS EAST ACROSS THE CWA. THERE MAY BE FIRE
CONCERNS AS SURFACE T/TDS SPREADS APPROACH 40F. SOUTHERLY WIND
SPEEDS LOOK TO INCREASE AS WELL AS A SURFACE TROUGH OF LOW PRESSURE
DEEPENS ACROSS THE HIGH PLAINS. BY EARLY SATURDAY...A WAVE WILL BE
PASSING THROUGH THE NORTHERN PLAINS WITHIN NEAR ZONAL FLOW
ALOFT...HOWEVER THE FORECAST MODELS SEEM TO BE KEYING ON MOST OF THE
QPF REMOVED FROM THE CWA...THUS WILL MAINTAIN THE INHERITED SLIGHT
CHANCE POPS FOR NOW AND NOT VENTURE ANY HIGHER. FOR SUNDAY AND
EARLY NEXT WEEK...THE LONG RANGE SOLUTIONS ALL ARRIVE AT A
SIGNIFICANT TROUGH ACROSS THE WESTERN CONUS...WITH THE POSSIBILITY
OF SEVERAL WAVES IMPACTING THE CWA...FIRST OF WHICH ARRIVES ON
SUNDAY. DIFFERENCES BETWEEN THE GFS AND EC ARE EVIDENT...MAINLY
WITH THE TIMING AND EVOLUTION OF THE MEAN WESTERN CONUS TROUGH...BUT
BOTH POINT TO A POTENTIALLY ACTIVE LATE WEEKEND/EARLY WORK WEEK SET
UP. BOTH ALSO INDICATE THE POTENTIAL OF A MYRIAD OF
PRECIPITATION...STARTING WITH TSTMS...SHOWERS...RAIN AND POSSIBLY
SNOW. WITH THE POTENTIAL SYSTEM STILL WAY OUT...DIDN/T WANT TO GET
TOO CUTE WITH PTYPE AND/OR LOCATIONS OF THE HIGHEST POPS. GENERALLY
BROAD-BRUSHED 30-40% POPS SUNDAY AND MONDAY...WITH SHOWERS POSSIBLY
CHANGING TO SNOW ACROSS THE NORTH LATE ON MONDAY...AND ACROSS THE
ENTIRE CWA EARLY TUESDAY MORNING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 620 AM CDT TUE APR 2 2013
VFR IS EXPECTED ALL AREAS TODAY AND TONIGHT. MIDLEVEL CLOUDINESS
ACROSS THE CNTL ROCKIES WILL SPREAD EAST TODAY AND TONIGHT
AFFECTING AREAS GENERALLY SOUTH OF INTERSTATE 80.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
610 AM CDT TUE APR 2 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 307 AM CDT TUE APR 2 2013
LATEST WATER VAPOR IMAGERY AND 500 MB RAP ANALYSIS SHOWED NORTHWEST
FLOW ALOFT ACROSS THE UPPER MISSISSIPPI RIVER VALLEY EARLY THIS
MORNING. A SHORTWAVE TROUGH WAS NOTED OVER SOUTHERN MANITOBA
RACING SOUTHEAST TOWARD THE AREA. SURFACE OBSERVATIONS INDICATED
HIGH PRESSURE STRETCHING FROM THE EASTERN DAKOTAS SOUTHEAST INTO
THE MIDDLE MISSISSIPPI RIVER VALLEY. THE HIGH WILL SLIDE EAST INTO
THE AREA TODAY. MEANWHILE THE SHORTWAVE TROUGH WILL MOVE THROUGH
BUT WILL DO LITTLE MORE THAN PRODUCE AN INCREASE IN CLOUD OVER
NORTHERN AND CENTRAL WISCONSIN WITH THE REST OF THE FORECAST AREA
EXPERIENCING MOSTLY SUNNY SKIES. PLAN ON HIGHS TODAY RANGING FROM
THE LOWER 30S OVER NORTHERN WISCONSIN TO THE UPPER 30S TO AROUND
40 ACROSS NORTHEAST IOWA. THE HIGH IS EXPECTED TO SLIDE OVER THE
AREA TONIGHT PROVIDING QUIET WEATHER. ANOTHER UNSEASONABLY COLD
NIGHT IS IN STORE FOR THE FORECAST AREA WITH LOWS FALLING INTO THE
UPPER TEENS TO LOWER 20S. FAVORED COLD SPOTS OVER NORTH CENTRAL
WISCONSIN...SUCH AS DIAMOND LAKE...COULD SEE LOWS FALL INTO THE
SINGLE DIGITS ABOVE ZERO.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 307 AM CDT TUE APR 2 2013
HIGH PRESSURE WILL CONTINUE TO DOMINATE THE WEATHER ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY ON WEDNESDAY WITH MOSTLY SUNNY SKIES
EXPECTED. THE SURFACE HIGH WILL SLIDE EAST LATE IN THE DAY AS A WEAK
COLD FRONT MOVES EAST OUT OF THE DAKOTAS. SOUTHERLY FLOW WILL
INCREASE ACROSS THE AREA AHEAD OF THIS FEATURE HELPING
TEMPERATURES WARM SLIGHTLY. PLAN ON HIGH TEMPERATURES RANGING FROM
THE LOWER 40S OVER NORTH CENTRAL WISCONSIN TO THE UPPER 40S TO
AROUND 50 ACROSS NORTHEAST IOWA. THE FRONT IS EXPECTED TO SAG
SOUTHEAST WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING AS A TROUGH
PUSHES EASTWARD ACROSS ONTARIO. FORECAST MODELS CONTINUE TO
GENERATE SOME LIGHT PRECIPITATION ALONG THE FRONT AS IT MOVES INTO
THE FORECAST AREA LATE WEDNESDAY NIGHT INTO THURSDAY MORNING.
FORCING IS NOT OVERLY IMPRESSIVE WITH THIS FEATURE WITH ONLY WEAK
ISENTROPIC LIFT NOTED. THE UPPER LEVEL FORCING IS PASSING WELL TO
THE NORTH OF THE REGION SO NOT EXPECTING MUCH PRECIPITATION.
HOWEVER...CANNOT RULE OUT SOME AREAS MEASURING SOME LIGHT RAIN MAINLY
ALONG AND NORTH OF INTESTATE 90. SOME SNOW COULD MIX IN EARLY IN
THE NORTH BEFORE TEMPERATURES WARM. HIGHS ON THURSDAY ARE EXPECTED
TO RANGE FROM LOWER TO MID 40S OVER NORTH CENTRAL WISCONSIN TO THE
LOWER 50S ACROSS NORTHEAST IOWA. THE FRONT WILL MOVE SOUTH AND
BECOME STATIONARY STRETCHING FROM THE WESTERN SOUTH DAKOTA EAST
THROUGH CENTRAL IOWA INTO NORTHERN ILLINOIS.
SURFACE HIGH PRESSURE IS EXPECTED TO RETURN BRIEFLY ON FRIDAY
PROVIDING ANOTHER QUIET DAY. MEANWHILE...A POTENT SHORTWAVE LOOKS TO
MOVE ACROSS THE PACIFIC NORTHWEST AND RACE EAST THROUGH THE DAKOTAS
LATE FRIDAY NIGHT. THE STATIONARY FRONT WILL LIFT NORTH AS THE WAVE
MOVES EAST AND ACT AS A BAROCLINIC ZONE. SURFACE LOW PRESSURE IS
EXPECTED TO DEVELOP ACROSS WESTERN SOUTH DAKOTA LATE FRIDAY
NIGHT...THEN MOVES EAST INTO THE UPPER MISSISSIPPI RIVER VALLEY
DURING THE DAY ON SATURDAY. STRONG 850 MB WARM AIR ADVECTION
DEVELOPS OVER THE AREA AHEAD OF THE APPROACHING LOW FRIDAY NIGHT
INTO SATURDAY MORNING. ISENTROPIC LIFT...ON THE 285-305K
SURFACES...INCREASES RAPIDLY AS THE LOW MOVES INTO THE AREA. THE
FORECAST MODELS HAVE BEEN SHOWING SOME DIFFERENCES REGARDING THE
PLACEMENT OF THE BOUNDARY WHICH WILL HAVE A HUGE IMPACT ON
PRECIPITATION TYPES. AT THIS TIME IT APPEARS THAT THE MAIN
PRECIPITATION TYPE WILL BE RAIN WITH PLENTY OF WARM AIR ADVECTING
NORTHWARD INTO THE REGION AHEAD OF THIS SYSTEM. THE PRECIPITATION
COULD START OUT AS SNOW EAST OF THE MISSISSIPPI RIVER LATE FRIDAY
NIGHT BUT SHOULD QUICKLY TRANSITION OVER TO ALL RAIN EARLY SATURDAY
MORNING. THE GEM AND GFS OFFER SIMILAR SOLUTIONS WITH THIS
SYSTEM...TAKING THE SURFACE LOW OVER SOUTHERN MINNESOTA ON SATURDAY
THEN ACROSS SOUTHERN WISCONSIN SATURDAY NIGHT. THE ECMWF OFFERS A
SLOWER AND MORE NORTHERLY SOLUTION...TAKING THE LOW OVER CENTRAL
MINNESOTA THROUGH NORTHERN WISCONSIN SATURDAY NIGHT. THE ECMWF
SOLUTION WOULD BRING MILD AIR INTO THE REGION ON SATURDAY...WITH
HIGHS CLIMBING INTO THE UPPER 50S TO LOWER 60S. ON THE OTHER HAND
THE GFS/GEM SOLUTION ARE ON THE COOLER SIDE WITH HIGHS RANGING
FROM THE UPPER 30S/LOWER 40S OVER NORTHERN WISCONSIN TO THE MID
50S ACROSS NORTHEAST IOWA. WILL LEAN TOWARDS A MODEL CONSENSUS
BLEND APPROACH. PLAN ON HIGHS RANGING FROM THE LOWER 40S OVER
NORTH CENTRAL WISCONSIN TO THE MID TO UPPER 50S SOUTH OF
INTERSTATE 90. THE LOW IS EXPECTED TO EXIT THE REGION ON SUNDAY.
AN ACTIVE PATTERN LOOKS TO DEVELOP MONDAY INTO TUESDAY AS A TROUGH
DIGS INTO THE SOUTHWEST CONUS. SOUTHWEST FLOW ALOFT COULD SET UP
OVER THE AREA. THE BAROCLINIC ZONE LOOKS TO REMAIN OVER THE UPPER
MIDWEST AS SHORTWAVE ENERGY EJECTS OUT OF OF THE SOUTHWEST FLOW
AND INTERACTS WITH IT. LATEST GUIDANCE SUGGESTS THE BOUNDARY WILL
STRETCH FROM NORTHERN OHIO WESTWARD THROUGH NORTHERN ILLINOIS
THROUGH SOUTHERN IOWA. WILL HAVE TO KEEP A CLOSE WATCH ON FUTURE
MODEL RUNS WITH THE POTENTIAL FOR THIS ACTIVE PATTERN TO BRING
SEVERAL ROUNDS OF PRECIPITATION TO THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 610 AM CDT TUE APR 2 2013
SKIES SHOULD REMAIN CLEAR FOR MOST OF THE NEXT 24 HOURS WITH A
BRIEF PERIOD OF SCATTERED MID TO UPPER LEVEL CLOUDS MOVING THROUGH
IN THE LATE MORNING/EARLY AFTERNOON. OTHERWISE...NORTHWEST WINDS
WILL PEAK AROUND 10KTS LATER THIS MORNING/EARLY AFTERNOON BEFORE
GOING LIGHT AND VARIABLE TONIGHT AS A RIDGE OF HIGH PRESSURE MOVES
IN ACROSS THE AREA.
&&
.HYDROLOGY...
ISSUED AT 307 AM CDT TUE APR 2 2013
THE COMBINATION OF SNOW MELT AND THE RAIN OVER THE WEEKEND HAS
RESULTED IN FLOODING ALONG THE TREMPEALEAU RIVER AT DODGE. THE
LATEST STAGE WAS 9.21FT. FLOOD STAGE IS 9FT. THE RIVER IS
EXPECTED TO CREST THIS MORNING AND THEN SLOWLY FALL LATE THIS
AFTERNOON INTO THIS EVENING.
THE BLACK RIVER HAS CRESTED BELOW FLOOD STAGE AT BLACK RIVER
FALLS. WITH PLENTY OF SNOW UPSTREAM...THIS RIVER WILL LIKELY STAY
HIGH FOR THE NEXT SEVERAL DAYS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...HALBACH
HYDROLOGY...WETENKAMP
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
610 AM MDT TUE APR 2 2013
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 345 AM MDT TUE APR 2 2013
AREA OF LOW PRESSURE DETACHED FROM THE MEAN FLOW WILL SLOWLY MOVE
OUT OF UTAH THIS MORNING AND INTO THE SOUTHERN PLAINS BY WEDNESDAY
NIGHT. THE FEW WEAK SHOWERS THAT HAVE PUSHED NORTHEAST ACROSS THE
CO/WY STATELINE HAVE DISSIPATED QUICKLY LOSING BEST QG VERTICAL
VELOCITIES WHICH ARE WELL SOUTH OF THE CWFA. ALTHOUGH STILL CANT
RULE OUT ISOLATED TO LOCALLY SCATTERED SHOWERS/DRIZZLE THROUGH THE
AFTERNOON...THESE WILL NEED TO RELY MAINLY ON LFQ H3 JET HELP AND
INSTABILITY. AS A RESULT...HAVE DECREASED PRECIPITATION CHANCES SOME
ESPECIALLY THIS MORNING...KEEPING THE HIGHEST IN AREAS NR THE CO/WY
STATELINE AND ALONG THE I80 CORRIDOR. ADDITIONALLY...PROGD LIFTED
INDICES WILL FALL SLIGHTLY NEGATIVE FOR AREAS WEST OF THE LARAMIE
RANGE THIS AFTERNOON. SO KEPT THE MENTION OF THUNDER FOR THESE
AREAS. ALTHOUGH WOULD EXPECT THE BEST THUNDER POTENTIAL TO BE OVER
THE SNOWY/SIERRA MADRE RANGES. THE OTHER CONCERN THIS MORNING IS
PATCHY FOG THAT HAS DEVELOPED ALONG THE INTERSTATE 80 SUMMIT. THE
AFFECTED AREA HAS THUS FAR BEEN CONFINED TO A FEW MILE STRETCH OF
I80. LATEST HRRR EVEN SHOWS SOME OF THIS STRATUS DESCENDING ALONG
THE EASTERN FOOTHILLS OF THE SOUTHERN LARAMIE RANGE TOWARDS DAYBREAK
AS WELL. FOR NOW...HAVE ADDED FOG MENTION TO THIS AREA THROUGH
MID-MORNING. H7 TEMPERATURES HOVERING AROUND -3C COMBINED WITH
THICKER CLOUD-COVER WILL TEMPER AFTERNOON HIGH TEMPERATURES
SOMEWHAT...WITH MAINLY 50S EXPECTED. THE EXCEPTION WILL BE AREAS IN
AND AROUND THE SOUTHEAST WYOMING MOUNTAINS WHERE HIGHS WILL ONLY
REACH THE 40S.
LATEST MODEL GUIDANCE HINTS AT THE POSSIBILITY OF PATCHY FOG FROM
CHEYENNE TO SIDNEY AGAIN LATER TONIGHT AND EARLY WEDNESDAY. SO HAVE
ADDED PATCHY MENTION. EXPECT MAINLY DRY CONDITIONS TONIGHT AS BEST
MOISTURE/LIFT ASSOCIATED WITH THE UPPER LOW EXITS TO THE SOUTHEAST
OF THE AREA.
HEIGHTS WILL RISE BEHIND THE DEPARTING LOW PRESSURE SYSTEM ON
WEDNESDAY. EXPECT A MOSTLY DRY DAY AS THIS WEAK TRANSITORY RIDGE
TRANSITIONS TO NORTHWEST FLOW. H7 TEMPERATURES WILL CLIMB TO
FREEZING AND WITH LESS CLOUD-COVER WILL SEE HIGHS CLIMB WELL INTO
THE 50S AND 60S AT ALL LOWER ELEVATIONS. MAY EVEN FLIRT WITH 70
NORTH OF THE PINE RIDGE. MODELS POINT TO ANOTHER WEAK FRONT WILL
PUSH SOUTH THROUGH THE AREA WEDNESDAY NIGHT. MOISTURE LOOKS TO BE
LIMITING FACTOR...SO KEPT WEDNESDAY NIGHT DRY FOR NOW.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 345 AM MDT TUE APR 2 2013
UPPER RIDGE WILL SHIFT EAST ACROSS THE CWA THURSDAY AND THURSDAY
NIGHT RESULTING IN MILD AND DRY WEATHER THROUGH MOST OF FRIDAY.
NEXT UPPER TROUGH TO AFFECT THE REGION WILL APPROACH ON FRIDAY AND
MAY SPREAD SOME SHOWERS INTO FAR WESTERN AND NORTHERN PARTS OF THE
CWA LATE IN THE DAY. THIS SYSTEM WILL PASS ACROSS FRIDAY NIGHT
BRINGING A MODEST PACIFIC FRONT AND A LITTLE COOLER TEMPERATURES
FOR SATURDAY. YET ANOTHER SHORTWAVE SHOULD PASS BY SATURDAY NIGHT
BEFORE A MORE SIGNIFICANT TROUGH DIGS OVER THE WESTERN CONUS
SUNDAY NIGHT AND MONDAY SPREADING MORE WIDESPREAD RAIN AND SNOW
SHOWERS ACROSS THE CWA AT THAT TIME. TEMPERATURES WILL ALSO COOL
SUNDAY THROUGH MONDAY DUE TO MORE CLOUD COVER AND LOWERING
HEIGHTS. MODELS SHOW THIS SYSTEM COULD BE A DECENT PRECIPITATION
PRODUCER FOR THE CWA EARLY NEXT WEEK BUT WILL SEE HOW FUTURE RUNS
TURN OUT BEFORE GETTING TOO EXCITED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 610 AM MDT TUE APR 2 2013
SLOW MOVING AREA OF LOW PRESSURE WILL MOVE FROM UTAH INTO
COLORADO TODAY. A FEW SHOWERS ALONG WITH MVFR/IFR CIGS WILL
DEVELOP AND LIFT NORTHEAST AFFECTING MAINLY SOUTHEAST WYOMING
TERMINALS TODAY. HAVE INCLUDED A TEMPO GROUP THROUGH 14Z/15Z AT
KLAR AND KCYS AS A BAND OF WEAK SHOWERS HAVE DEVELOPED TO THEIR
NORTH. OTHERWISE...EXPECT VFR CONDITIONS TO PREVAIL AT AREA
AIRPORTS. FOG POTENTIAL WILL RETURN AFTER 06Z TONIGHT FROM KCYS TO
KSNY...SO HAVE INCLUDED A VCFG MENTION FOR NOW.
&&
.FIRE WEATHER...
ISSUED AT 345 AM MDT TUE APR 2 2013
MINIMAL FIRE WEATHER CONCERNS EXPECTED THIS WEEK. AN AREA OF LOW
PRESSURE WILL MOVING FROM UTAH INTO COLORADO TODAY. CLOUDS AND LIGHT
PRECIPITATION CHANCES WILL HOLD HIGH TEMPERATURES DOWN AND MINIMUM
RELATIVE HUMIDITIES UP TODAY. THERE WILL BE UP TO A FEW INCHES OF
NEW SNOW OVER THE SNOWY AND SIERRA MADRES THROUGH TODAY.
PRECIPITATION WILL DECREASE TONIGHT...WITH DRIER CONDITIONS SETTLING
IN FOR WEDNESDAY THROUGH FRIDAY. WARMER TEMPERATURES ARE EXPECTED AS
WELL...WITH 70S RETURNING TO EASTERN PORTIONS OF THE DISTRICT BY
WEEKS END. MINIMUM RELATIVE HUMIDITIES WILL HOVER IN THE 20 TO 30
PERCENT RANGE EACH DAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...HAHN
LONG TERM...RE
AVIATION...HAHN
FIRE WEATHER...HAHN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1059 AM MDT TUE APR 2 2013
.UPDATE...
&&
.SHORT TERM...MOST IF NOT ALL OF CWA HAS BEEN UNDER AN AREA OF
DRIER AIR AHEAD OF THE MAIN UPPER LOW OVER EASTERN UTAH. SOME
CLEARING NOTED EARLIER ACROSS SUMMIT COUNTY. LATEST MODELS DO HAVE
THE MOISTURE INCREASING AND PRECIP REDEVELOPING BY THE AFTERNOON.
BEGINNING TO SEE SOME CLOUD ENHANCEMENT ACROSS MOUNTAINS AND ALONG
FOOTHILLS. BASED ON CURRENT CONDITIONS...BACKED OFF ON PRECIP
CHANCES ACROSS MOUNTAINS...FOOTHILLS AND VALLEYS THIS MORNING. AS
FOR PLAINS...DROPPED THE MENTION OF THE PRECIP THROUGH 18Z MOST
AREAS EXCEPT NEAR THE FOOTHILLS AND WYOMING BORDER. KEPT SOME LOW
POPS ALONG THE PALMER DIVIDE AS WELL. BY AFTERNOON...INCREASING
MOISTURE AND INSTABILITY ALONG WITH LIFT WILL ALL COMBINE TO
INCREASE THE PRECIP CHANCES. LATEST RAP INCREASES THE EASTERLY
FLOW AFTER 21Z...PROVIDING UPSLOPE. OVERALL...CURRENT FORECASTS FOR
THIS AFTERNOON AND EVENING SEEM REASONABLE. WILL BOOST THE
FOOTHILLS POPS A BIT AFTER 21Z THROUGH THE EVENING. SNOW LEVELS
BETWEEN 5 AND 7 THOUSAND FEET THIS AFTERNOON STILL SEEMS
REASONABLE...LOWERING TO 4 TO 6 THOUSAND FEET TONIGHT. OVERALL...
PRECIP WILL GENERALLY BE LIGHT. THERE MAY BE SOME AREAS WHERE
SHOWERS COULD BE HEAVIER...PERHAPS IN EAST FACING SLOPES.
.AVIATION...EARLIER CLEARING HAD FILLED IN AS LOCAL MESOCYCLONE
BROUGHT MVFR CEILINGS TO THE AREA AIRPORTS. STILL EXPECTING
CEILINGS TO IMPROVE A BIT AROUND 18Z...THEN LOWER AGAIN AFTER 21Z
AS RAIN SHOWERS DEVELOP. SOME SNOW WILL MIX WITH THE RAIN BY 00Z.
AREAS OF MVFR/IFR CONDITIONS POSSIBLE WITH THE HEAVIER SHOWERS
FROM 21Z THROUGH 06Z...THEN A GRADUAL IMPROVEMENT OVERNIGHT.
INSTRUMENT APPROACHES LIKELY FOR MOST OF THE TIME.
&&
.PREV DISCUSSION... /ISSUED 451 AM MDT TUE APR 2 2013/
SHORT TERM...UPPER LOW OVER UTAH WILL MOVE SLOWLY ESE TOWARD
SOUTHEAST COLORADO BY WEDNESDAY MORNING. MEANWHILE MOIST SOUTH TO
SOUTHEAST LOW LEVEL FLOW WILL CONTINUE OVER THE PLAINS. AIRMASS
WILL REMAIN SLIGHTLY UNSTABLE...WITH SOME LOW LEVEL STABILITY OVER
THE PLAINS THIS MORNING AS THERE IS SOME WARM ADVECTION OFF THE
GROUND...AND THEN SLIGHT COOLING ALOFT THIS EVENING AS THE COLD
POOL WITH THE LOW MOVES OVER. WITH THE DRIER AIR ALOFT THERE IS
NOT MUCH TO PRODUCE SIGNIFICANT SHOWERS THIS MORNING...THOUGH WEAK
CONVERGENCE AND LIFT IN THE MOIST LOWER LEVELS COULD PRODUCE SOME
DRIZZLE OR SHALLOW SHOWER ACTIVITY. CONVECTION ON THE EDGE OF THE
COLD POOL COULD ALSO CLIP THE NORTHERN MOUNTAINS. EXPECT SHOWERS
TO BREAK OUT THIS AFTERNOON AS BEST LIFT...SLIGHT COOLING...AND
LOW LEVEL CONVERGENCE ALL INCREASE. BEST TIME WILL LIKELY BE IN
THE LATE AFTERNOON AND EARLY EVENING AS THE LOW SLIDES SOUTH OF
OUR AREA AND WITH A LITTLE HELP FROM DIURNAL HEATING. I LOWERED
POPS A LITTLE THIS MORNING...AND RAISED THEM MAINLY FOR THE
MOUNTAINS THIS AFTERNOON AND EVENING. AMOUNTS WILL GENERALLY BE
LIGHT THOUGH IF THERE COULD BE SOME ORGANIZATION THE FOCUSED
CONVECTION COULD PRODUCE HEAVIER AMOUNTS. TWO POSSIBILITIES FOR
THIS...SLOW MOVING SHOWERS OVER THE CREST OR EAST SLOPES OF THE
FRONT RANGE COULD PRODUCE SUSTAINED MODERATE TO HEAVY SNOW FOR
SEVERAL HOURS. ALSO MODELS HAVE BEEN PRODUCING NARROW SNOW BANDS
ON THE PLAINS IN THE DEFORMATION ZONE ON THE NORTH SIDE OF THE
LOW WITH UP TO 6 INCHES OF SNOW...BUT IN DIFFERENT PLACES. THIS IS
CERTAINLY POSSIBLE THOUGH THE DEFORMATION ZONE WILL LIKELY BE
SINKING SOUTHWARD WHICH SHOULD SPREAD THAT BAND OUT A BIT.
TEMPERATURES WILL ALSO BE RATHER WARM...SO FAR WE HAVE BEEN A BIT
WARMER THAN THE MODELS SHOW. EXPECTING SNOW LEVELS BETWEEN 5 AND 7
THOUSAND FEET TODAY AND 4 TO 6 THOUSAND FEET TONIGHT. WE MAY YET
NEED TO RAISE POPS FOR A BETTER CHANCE OF LIGHT PRECIPITATION AT
THE PEAK OF THIS LATE TODAY...BUT OVERALL PRECIPITATION WILL
GENERALLY BE LIGHT WITH WARM TEMPERATURES. SOME TRAVEL IMPACT
POSSIBLE UNDER HEAVIER SHOWERS...BUT EXPECT COVERAGE OF THAT TO BE
LOCALIZED. SYSTEM WILL SINK SOUTH LATER TONIGHT AND WE SHOULD SEE
SOME CLEARING IN THE NORTH BY MORNING.
LONG TERM...MODELS HAVE THE UPPER LOW OVER SOUTHEASTERN
COLORADO/NORTH CENTRAL NEW MEXICO AT 12Z WEDNESDAY MORNING. BY
12Z THURSDAY MORNING...IT IS WELL EAST OF THE CWA WITH
NORTHWESTERLY FLOW ALOFT IN PLACE HERE. BY THURSDAY NIGHT...AN
ADVANCING UPPER RIDGE`S AXIS IS OVER THE CWA. THE FLOW ALOFT IS
WESTERLY AND FAIRLY LIGHT. THE QG VERTICAL VELOCITY FIELDS SHOW
WEAK DOWNWARD SYNOPTIC SCALE ENERGY FOR THE FORECAST AREA
WEDNESDAY THROUGH THURSDAY EVENING. THE BOUNDARY LAYER FLOW LOOKS
TO ADHERE TO NORMAL DUIRNAL PATTERNS ALL FOUR PERIODS WITH A
FAIRLY WEAK PRESSURE GRADIENT PROGGED. FOR MOISTURE...THERE IS
SOME LINGERING ON WEDNESDAY...BUT IT DECREASES THROUGH THE DAY. IT
IS PRETTY DRY WEDNESDAY NIGHT. THERE IS SOME MID AND UPPER LEVEL
MOISTURE AROUND THURSDAY AND THURSDAY...WITH THE GFS SHOWING A
LOT IN THE UPPER LEVELS AFTER 06Z FRIDAY MORNING EARLY. THERE IS A
BIT OF CAPE PROGGED OVER THE MOUNTIANS AND FOOTHILLS ON THE NAM
ONLY FOR LATE DAY WEDNESDAY. THERE IS A TAD OF MEASURABLE
PRECIPITATION ON THE QPF FIELDS LATE DAY WEDNESDAY...OTHERWISE
NOTHING THROUGH THE PERIODS. WILL GO WITH 20-30%S IN THE MOUNTAINS
ON WEDNESDAY. OTHERWISE NO POPS ANYWHERE FOR THE REST OF THE
PERIODS. FOR TEMPERATURES...WEDNESDAY`S HIGHS ARE 3-6 C WARMER
THAN TUESDAY`S. THURSDAY`S HIGHS ARE 3-5 C WARMER THAN
THURSDAY`S. FOR THE LATER DAYS...FRIDAY THROUGH MONDAY...MODELS
HAVE A WEAK UPPER TROUGH TO MOVE ACROSS FRIDAY AFTERNOON AND
EVENING. ON SATURDAY INTO SUNDAY...FAIRLY STRONG WESTERLY FLOW
ALOFT IS PROGGED...WITH UPPER TROUHGING SUNDAY NIGHT THROUGH
MONDAY NIGHT. MOISTURE INCREASES ON FRIDAY AND THERE IS QUITE A
BIT AROUND LATE SUNDAY THROUGH MONDAY NIGHT.
AVIATION...EXPECT SCATTERED RAIN SHOWERS TO DEVELOP THIS
AFTERNOON AND CONTINUE THIS EVENING...MIXING WITH OR CHANGING TO
SNOW AFTER DARK. TEMPERATURES SHOULD STAY AT OR ABOVE FREEZING
WHICH WILL LIMIT SNOW ACCUMULATION. MVFR CONDITIONS WILL GRADUALLY
LIFT THIS MORNING...THEN CEILINGS WILL LOWER AGAIN AS THE SHOWERS
DEVELOP LATE TODAY WITH AREAS OF MVFR CEILINGS/VISIBILITIES AND
IFR CONDITIONS POSSIBLE IN THE HEAVIER SHOWERS FROM 21Z TO
06Z...THEN IMPROVING CONDITIONS AGAIN. INSTRUMENT APPROACHES TO
KDEN WILL LIKELY BE NEEDED MOST OF THE TIME THROUGH THIS EVENING.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
138 PM EDT TUE APR 2 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EDT TUE APR 2 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF OVER
THE E HALF OF NAMERICA DOWNSTREAM OF RDG OVER WRN CANADA. CWA
REMAINS DOMINATED BY COLD CYC NW FLOW IN THE WAKE OF SLOWLY
DEPARTING CLOSED LO OVER WRN QUEBEC. ALTHOUGH H85 TEMPS RANGING FM
-14C OVER THE W TO -16C OVER THE E AND INVRN BASE NEAR H8 ARE
SUFFICIENTLY COLD/HI FOR LES EVEN IN THE ABSENCE OF ANY DYNAMIC
FORCING...UPSTREAM 00Z INL/YPL RAOBS ARE SO DRY...WITH THE H925
DEWPT DEPRESSION 15C AT INL IN INVERTED V T/TD PROFILE...THAT THERE
ONLY A FEW WEAK CLD BANDS OVER THE W HALF OF LK SUP STREAMING INTO
THE WRN ZNS. WITH A LONGER FETCH OVER THE E HALF AND A WEAK SFC TROF
PASSING THRU THIS AREA...MORE CLDS/SOME LES BANDS ARE EVIDENT
STREAMING INTO THE CWA E OF MQT. BUT DRYNESS OF AIRMASS IS EVIDENT
IN LO REFLECTIVITIES. LOOKING FARTHER UPSTREAM...THERE IS A FAIRLY
VIGOROUS SHRTWV NEAR LK WINNIPEG DIGGING SEWD. BUT SINCE THE 00Z THE
PAS MANITOBA RAOB IS ALSO QUITE DRY WITH INVERTED V T/TD PROFILE IN
THE LLVLS...THERE ARE ONLY SOME PATCHY MID/HI CLDS IN THE PVA
ASSOCIATED WITH THIS FEATURE. ANOTHER SHRTWV OVER HUDSON BAY IS
DIVING SWD.
EARLY THIS MRNG/TODAY...WITH NOCTURNAL COOLING EARLY THIS MRNG AND
SOME ENHANCED LLVL CNVGC ALONG WEAK SFC TROF...EXPECT SCT-NMRS -SHSN
TO IMPACT THE ERN ZNS THRU THIS MRNG. OVER THE W...THERE SHOULD BE
LTL IF ANY LES OR EVEN LK CLDS THRU 09Z GIVEN THE UPSTREAM
DRYNESS...BUT MODELS SHOW AREA OF DPVA/H85-5 QVECTOR CNVGC
ASSOCIATED WITH SHRTWV DIGGING THRU MN IMPACTING THE FAR W BY 12Z.
SUSPECT MORE CLDS/A FEW -SHSN MIGHT DVLP IN PRESENCE OF NOCTURNAL
COOLING...BUT LLVL DRYNESS WL LIMIT COVERAGE/INTENSITY OF ANY SHSN
THAT MIGHT POP UP. IF THERE IS ANY SHSN...THESE SHOULD DIMINISH ONCE
THE FORCING PASSES TO THE S BY 15Z AND DAYTIME HEATING BEGINS TO
DISRUPT THE LES PROCESS. LATE IN THE DAY...NEXT SHRTWV OVER HUDSON
BAY IS PROGGED TO DIG INTO THE UPR LKS WITH ACCOMPANYING DPVA AND
H85-5 QVECTOR CNVGC IMPACTING THE CWA. ALTHOUGH DAYTIME HEATING
MIGHT ALSO DISRUPT THE LES OVER THE E HALF IN THE AFTN...THE ARRIVAL
OF THIS FORCING MIGHT CAUSE AN UPTICK OF SHSN AGAIN TOWARD 00Z
ESPECIALLY OVER THE E HALF CLOSER TO DEEPER MSTR/COLDER AIR.
AS FOR TEMPS...PREFER TO TEND TOWARD THE HIER END OF GUIDANCE WITH A
GOOD DEAL OF SUNSHINE...AT LEAST OVER THE W AND SCENTRAL.
TNGT...SHRTWV DROPPING S INTO THE UPR LKS AND ACCOMPANYING DYNAMIC
FORCING IS PROGGED TO CROSS THE ERN COUNTIES. WITH LOWER H85 TEMPS
ARND -17C CLOSER TO THE CYC SIDE OF THE TRACK OF THIS DISTURBANCE AS
WELL AS DEEPER MSTR/SOMEWHAT HIER INVRN SHOWN THERE ON FCST SDNGS...
OPTED TO RAISE POPS INTO THE LIKELY RANGE NEAR LK SUP E OF MQT AS
THESE EVENTS OCCUR DURING THE MORE FAVORABLE NOCTURNAL COOLING.
EXPECT MUCH LESS IF ANY ACTIVITY OVER THE W ON THE ACYC SIDE OF THE
SHRTWV PASSAGE AND WHERE FCST SNDGS SHOW MUCH DRIER AIR AND HIER H85
TEMPS/LOWER INVNR BASE. EXPECT THE LOWEST MIN TEMPS TOWARD THE LOWER
END OF GUIDANCE OVER THE INTERIOR W UNDER THE DRIER AIR AND WHERE
WINDS WL BE LIGHTER.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 520 AM EDT TUE APR 2 2013
LOOKS LIKE A PATTERN CHANGE IS IN THE OFFING OVER THE NEXT FEW WEEKS
THAT WILL TRANSITION THE PERSISTENT BELOW NORMAL TEMP REGIME TOWARD
AN ABOVE NORMAL ONE. THE AO AND NAO WHICH HAVE BEEN IN A PREVAILING
NEGATIVE PHASE SINCE EARLY/MID FEB ARE BOTH FORECAST TO TREND TO THE
POSITIVE PHASE...WITH THE AO BECOMING STRONGLY POSITIVE. THIS
SUPPORTS A TREND TOWARD ABOVE NORMAL TEMPS HEADING INTO MID/LATE
APRIL...BUT THIS DOESN`T PRECLUDE THE POTENTIAL FOR MORE WINTRY PCPN
EVENTS BEFORE THE WARMER PATTERN SETS IN. THE PATTERN ALSO APPEARS
TO BE SHIFTING TOWARD AN ACTIVE ONE OVER THE NEXT 2 WEEKS. INTO THE
UPCOMING WEEKEND...FLOW WILL TREND PROGRESSIVE AND FLATTER WITH A
COUPLE OF SHORTWAVES TO AFFECT THE UPPER LAKES...THE FIRST WED
NIGHT/THU AND A SECOND MORE IMPORTANT WAVE SAT. EARLY NEXT WEEK...AN
AMPLIFIED TROF WILL BE DEVELOPING OVER THE WRN CONUS...SIGNALING THE
POTENTIAL FOR MORE SIGNIFICANT PCPN EVENTS NEXT WEEK FROM THE
CNTRL/SRN PLAINS TO THE GREAT LAKES AS THE GULF OPENS UP. THIS COULD
MEAN ONE OR MORE UNWELCOMED RAIN EVENTS ON A MELTING SNOWPACK WHICH
IS STILL DEEP IN THE LAKE EFFECT AREAS OR MORE SNOW COULD STILL BE
ADDED. IN RECENT DAYS...MEDIUM RANGE GUIDANCE HAS TONED DOWN THE
WARMING NEXT WEEK...SO MORE SNOW IS STILL A REAL POSSIBILITY.
BEGINNING WED...SFC HIGH PRES WILL QUICKLY SHIFT ACROSS THE WRN
GREAT LAKES AHEAD OF THE FIRST SHORTWAVE THAT WILL BE TRACKING
ACROSS SASKATCHEWAN/MANITOBA. IF ANY LIGHT LES IS LINGERING OVER THE
ERN FCST AREA TO START THE DAY...IT WILL END QUICKLY IN THE MORNING.
AFTER A PERIOD OF SUNSHINE...HIGH CLOUDS WILL BE ON THE INCREASE.
SUNSHINE WILL SUPPORT A STRONG DIURNAL TEMP SPREAD. AFTER MORNING
LOWS IN THE SINGLE DIGITS OVER THE INTERIOR W...TEMPS SHOULD REBOUND
INTO THE UPPER 30S/LWR 40S.
SHORTWAVE WILL MOVE ACROSS NRN ONTARIO WED NIGHT/THU MORNING. WITH
STRONG DEEP LAYER FORCING/IMPRESSIVE 500MB HEIGHT FALLS (AROUND
200M/12HR) PASSING WELL TO THE N OF HERE...MAIN PCPN AREA WILL PASS
TO THE N OF UPPER MI. NONETHELESS...50-80M HEIGHT FALLS AT 500MB...
RIBBON OF MODEST DEEP LAYER FORCING PER QVECTORS AND ISENTROPIC
ASCENT SUGGEST SOME PCPN POTENTIAL ACROSS THE FCST AREA. WITH
ISENTROPIC ASCENT WEAKENING AS IT SHIFTS ACROSS THE UPPER LAKES...
AND LOW-LEVEL DRY AIR TO OVERCOME INITIALLY...NOTHING MORE THAN LOW
CHC POPS APPEAR WARRANTED ATTM. ALTHOUGH LOW-LEVEL TEMPS ARE JUST
ABOVE 0C PRIOR TO POTENTIAL PCPN ARRIVING...EVAPORATIVE COOLING
SHOULD BE SUFFICIENT SO THAT SNOW BECOMES THE MAIN PTYPE IN MOST
AREAS. PCPN CHC WILL END W TO E THU MORNING WITH DRY WEATHER
FOLLOWING THRU THU NIGHT/FRI AS SFC HIGH PRES RIDGE BUILDS SE INTO
THE UPPER LAKES. 850MB TEMPS FALLING TO AROUND -12C THU NIGHT/FRI
MORNING WILL BE AT THE THRESHOLD FOR LES. HOWEVER...SINCE LOW-LEVEL
FLOW BECOMES MORE ANTICYCLONIC DURING THE NIGHT AND AIR MASS IS
FAIRLY DRY IN THE LOW-LEVELS...WILL NOT INCLUDE ANY MENTION OF
-SHSN. OVER THE W...FLOW IS MORE DIVERGENT...SO THERE MAY NOT EVEN
BE MUCH IN THE WAY OF CLOUDS. OPTED TO GO BLO GUIDANCE THERE THU
NIGHT AS WINDS WILL PROBABLY FALL OFF TO CALM AS HIGH PRES RIDGE
NEARS. ALTHOUGH LOWERED MINS TO THE LOW/MID TEENS...TEMPS COULD
EASILY FALL INTO THE SINGLE DIGITS.
FRI NIGHT/SAT...ATTENTION TURNS TO THE SECOND MORE IMPORTANT
SHORTWAVE TRACKING ACROSS THE NRN CONUS IN FLATTER FLOW REGIME.
MEDIUM RANGE GUIDANCE IS MOVING TOWARD SLIGHTLY BETTER AGREEMENT
WITH SYSTEM...BUT IMPORTANT DETAILS HAVE YET TO BE NARROWED DOWN.
THE GFS WHICH HAS BEEN CONSISTENTLY FARTHER S HAS TRENDED A LITTLE
FARTHER N WITH WAVE AND IS IN DECENT AGREEMENT WITH THE GLOBAL GEM.
THE ECMWF HAS BEEN CONSISTENTLY FARTHER N. THE GFS TRACK LOOKS TO
SUPPORT ALL SNOW FOR THE FCST AREA AS THE 850MB LOW TRACKS ALONG
WI/UPPER MI BORDER AND 850MB TEMPS REMAIN BLO 0C AND 1000-850MB
THICKNESS IS NO HIGHER THAN 1295M. THE GLOBAL GEM MOSTLY SUPPORTS
ALL SNOW WITH A POSSIBLE CHANGEOVER TO RAIN S AND SE...BUT ITS
SLOWER/MORE WRAPPED UP SYSTEM DOES NOT APPEAR TO FIT THE DEVELOPING
FLATTER FLOW REGIME. HOWEVER...THE 00Z ECMWF ALSO TRENDED MUCH
SLOWER AND SHARPER WITH SHORTWAVE...SO THIS MAY BE AN IMPORTANT
TREND TO MONITOR IN FUTURE MODEL RUNS. THE FARTHER N ECMWF SUGGESTS
MORE OF A MIXED PCPN EVENT WITH MORE SNOW THAN RAIN N AND MORE RAIN
THAN SNOW S. THE HEAVIEST SWATH OF PCPN PASSES ACROSS NRN UPPER MI
IN THE ECMWF...JUST S IN THE GFS AND CLIPS THE SRN FCST AREA IN THE
GLOBAL GEM. WHILE THE DETAILS OF SHORTWAVE TRACK...RESULTING PCPN
AREA AND THE ALL IMPORTANT TEMP PROFILE HAVE YET TO BE AGREED
UPON...WHAT IS A LITTLE MORE CERTAIN IS THAT THIS WAVE MAY BE A
RATHER IMPRESSIVE PCPN PRODUCER DESPITE THE FLATTER FLOW REGIME.
STRONG WAA IS NOTED BY ALL GUIDANCE WITH 850MB WINDS AROUND 50KT.
THE FRONTOGENESIS SIGNAL IS ALSO QUITE STRONG. PROXIMITY OF STEEP
MIDLEVEL LAPSE RATES NEAR THE SRN EDGE OF THE PCPN AREA SUGGESTS
THERE WILL PROBABLY BE SOME CONVECTION AS IS OFTEN SEEN WITH WAVES
RUNNING ALONG THE BAROCLINIC ZONE AT THIS TIME OF YEAR. IT WILL BE A
SYSTEM TO WATCH.
IN THE WAKE OF THE SAT SYSTEM...DRY WEATHER SHOULD FOLLOW FOR SUN
UNDER WEAK SFC HIGH PRES RIDGE...THOUGH IF THE SLOWER GLOBAL GEM AND
ECMWF ARE RIGHT...SOME PCPN COULD LINGER THRU AT LEAST PART OF SUN.
ATTENTION THEN TURNS TO THE SW FOR MON/TUE AS TROF AMPLIFIES INTO
THE WRN CONUS. AMPLIFYING TROF MAY SEND SEVERAL SHORTWAVES INTO THE
GREAT LAKES NEXT WEEK WITH THE FIRST PERHAPS AS SOON AS MON. AS
WOULD BE EXPECTED WITH A DEEPENING WRN TROF...MODELS ARE AND WILL
CONTINUE TO HAVE TROUBLE WITH TIMING AND PLACEMENT OF SHORTWAVES
EJECTING NE...SO THERE IS LITTLE CONFIDENCE RIGHT NOW IN THE PCPN
FCST MON/TUE. WITH GULF OPENING UP AHEAD OF THE LARGE SCALE WRN
TROF...ANY SHORTWAVES AFFECTING THE AREA COULD BE MDT/HVY PCPN
PRODUCERS NEXT WEEK...AND PCPN COULD BE SNOW FOR PORTIONS OF UPPER
MI.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 135 PM EDT TUE APR 2 2013
AN UPPER LEVEL TROUGH WILL PASS THROUGH THE EASTERN PORTION OF THE
UPPER PENINSULA LATE THIS EVENING INTO THE OVERNIGHT HOURS...HOWEVER
THIS SHOULD DO NOTHING MORE THAN BRING INCREASED CLOUD COVER FOR
MAINLY THE CMX AND SAW TAF SITES. CEILINGS AND VISIBILITIES ARE
EXPECTED TO REMAIN VFR THROUGH THE TAF PERIOD. HIGH PRESSURE BUILDING
INTO THE WEST WILL ALLOW THE WINDS TO DECREASE AND BECOME VARIABLE
OVERNIGHT AT THE IWD TAF SITE...BEFORE SHIFTING TO THE SOUTH BY LATE
WEDNESDAY MORNING AS THE HIGH SHIFTS TO THE EAST OF THE AREA. &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 520 AM EDT TUE APR 2 2013
WHERE THE PRES GRADIENT WILL BE SHARPER CLOSER TO DEPARTING LO PRES
IN SE CANADA...EXPECT NNW WINDS UP TO 30 KTS THRU TONIGHT OVER THE E
ALONG WITH FREEZING SPRAY. LIGHTER WINDS UP TO 20 KTS WILL PREVAIL
OVER THE W WHERE THE GRADIENT WILL BE WEAKER. AFTER A BRIEF PERIOD
OF LIGHT WINDS FOR A PORTION OF WED AS HIGH PRES QUICKLY PASSES...S
TO SW WINDS WILL QUICKLY RAMP UP TO 20-30KT WED AFTN/EVENING AHEAD OF
LOW PRES TRACKING E INTO NRN ONTARIO. ALTHOUGH LOW-LEVEL TEMP PROFILE
IS STABLE...HEALTHLY PRES FALLS PASSING ACROSS NRN ONTARIO SUGGEST
THERE WILL BE SOME POTENTIAL FOR A SHORT PERIOD OF GALES WED NIGHT.
WINDS SHIFT WNW FOR THU. WHILE WINDS WILL DIMINISH TO 15-25KT OVER
THE W...20-30KT WINDS WILL CONTINUE OVER THE E. WINDS WILL THEN
DIMINISH TO LIGHT (UNDER 15KT) FRI HAS HIGH PRES RIDGE ARRIVES. WINDS
SHOULD REMAIN UNDER 20KT SAT...BUT WITH UNCERTAINTY IN THE
STRENGTH/TRACK OF NEXT LOW PRES TRACKING E INTO THE GREAT LAKES...
WINDS COULD END UP STRONGER THAN CURRENTLY FCST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...ROLFSON
AVIATION...KEC
MARINE...KC/ROLFSON
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1238 PM CDT TUE APR 2 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 316 AM CDT TUE APR 2 2013
TODAY...THE HIGH PLAINS DISTURBANCE OPERATING ON LIMITED
MOISTURE WILL DRIFT VERY SLOWLY EAST SOUTHEAST TODAY AND TONIGHT.
GIVEN THE DRY AIR AT THE LOWER LEVELS...SPRINKLES LOOKED REASONABLE
ACROSS SWRN NEB. MID LEVEL CLOUDINESS WILL HANG ON TODAY AND TONIGHT
ACROSS THE SOUTHWEST. ELSEWHERE...MOSTLY CLEAR. A WEAK AREA FOR
FRONTOGENESIS HAS DEVELOPED ACROSS THE MISSOURI BASIN. THE RAP MODEL
IS LIFTING THIS FEATURE UP INTO THE MIDWEST TODAY.
OTHERWISE...A WARM FRONT SHOULD LIFT NORTH INTO THE SANDHILLS TODAY
WHILE WINDS NORTH OF THE FRONT BACK TO THE EAST AND NORTHEAST. FULL
SUN IN MANY AREAS SHOULD SEND HIGHS TO AROUND 60. THE RAP SUGGESTED
LOWER 60S IN MANY AREAS BUT THAT MODEL TENDS TO RUN WARM. RH DROPS
TO 20 TO 25 PERCENT THIS AFTERNOON BUT WINDS SHOULD REMAIN BELOW 15
MPH WITH WEAK WINDS CARRYING ALL THE WAY TO 700 MB.
TONIGHT...LOW PRESSURE DEVELOPS ACROSS THE NRN HIGH PLAINS WHICH
SETS UP A STRONGER SOUTHWEST WIND TONIGHT. THIS WILL HOLD LOWS
AROUND FREEZING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 316 AM CDT TUE APR 2 2013
12Z WEDNESDAY AND BEYOND. MAIN FORECAST CONCERN GOING
IN THE EXTENDED PERIOD REVOLVES AROUND THE DEVELOPMENT OF AN
AMPLIFIED WESTERN CONUS TROUGH...WHICH MAY BRING PERIODS OF
WIDESPREAD PRECIPITATION BACK ACROSS THE CWA THIS WEEKEND AND
ESPECIALLY EARLY NEXT WEEK. BUT FIRST...AN UPPER LOW AND ATTENDANT
TROUGH THAT WILL BE POSITIONED ACROSS SOUTHEAST COLORADO/NORTHERN
NEW MEXICO EARLY WEDNESDAY WILL PROGRESS SOUTHEAST ACROSS TEXAS AND
THE SOUTHERN PLAINS THROUGH THURSDAY. THIS WILL ALLOW A TRANSITION
FROM SPLIT FLOW ALOFT OVER THE CENTRAL PLAINS...TO NORTHWESTERLY...AND
EVENTUALLY SOUTHWESTERLY AS A UPPER RIDGE BUILDS ACROSS THE PLAINS
ON FRIDAY. AT THE SAME TIME...AN UPPER TROUGH AND ATTENDANT LOW
WILL BE RAPIDLY PROGRESSING ACROSS THE CANADIAN ROCKIES TOWARD
SOUTHERN ONTARIO...DRAGGING A COLD FRONT THROUGH THE
NORTHERN/CENTRAL HIGH PLAINS EARLY ON THURSDAY. TEMPERATURES ON
WEDNESDAY WILL BE ATYPICAL...WITH THE WARMEST READINGS ACROSS
NORTHERN NEBRASKA...WHERE HIGHS IN THE LOW TO MID 60S SHOULD
PREVAIL. FOR SOUTHERN NEBRASKA...HIGHS ON WEDNESDAY WILL BE SOME
5-8F COOLER AS THE INFLUENCE OF THE SOUTHERN PLAINS UPPER LOW SHOULD
ALLOW FOR AN INCREASE CLOUDINESS AND SLIGHTLY COOLER TEMPERATURES
ALOFT. SLIGHTLY COOLER ACROSS THE NORTH ON THURSDAY AS MODIFIED
ARCTIC HIGH PRESSURE RECYCLES SOME COOLER AIR BACK INTO NORTH
CENTRAL NEBRASKA...ANTICIPATING HIGHS MAINLY IN THE MID 50S.
TEMPERATURES ACROSS THE SOUTH AND WEST WILL WARM SEVERAL DEGREES
UNDER FULL SUN AND WEAK WARMING ALOFT...MID 60S SHOULD PREVAIL.
FRIDAY WILL BE THE WARMEST DAY OF THE WEAK FOR ALL AREAS AS THE
UPPER RIDGE AXIS SHIFTS EAST ACROSS THE CWA. THERE MAY BE FIRE
CONCERNS AS SURFACE T/TDS SPREADS APPROACH 40F. SOUTHERLY WIND
SPEEDS LOOK TO INCREASE AS WELL AS A SURFACE TROUGH OF LOW PRESSURE
DEEPENS ACROSS THE HIGH PLAINS. BY EARLY SATURDAY...A WAVE WILL BE
PASSING THROUGH THE NORTHERN PLAINS WITHIN NEAR ZONAL FLOW
ALOFT...HOWEVER THE FORECAST MODELS SEEM TO BE KEYING ON MOST OF THE
QPF REMOVED FROM THE CWA...THUS WILL MAINTAIN THE INHERITED SLIGHT
CHANCE POPS FOR NOW AND NOT VENTURE ANY HIGHER. FOR SUNDAY AND
EARLY NEXT WEEK...THE LONG RANGE SOLUTIONS ALL ARRIVE AT A
SIGNIFICANT TROUGH ACROSS THE WESTERN CONUS...WITH THE POSSIBILITY
OF SEVERAL WAVES IMPACTING THE CWA...FIRST OF WHICH ARRIVES ON
SUNDAY. DIFFERENCES BETWEEN THE GFS AND EC ARE EVIDENT...MAINLY
WITH THE TIMING AND EVOLUTION OF THE MEAN WESTERN CONUS TROUGH...BUT
BOTH POINT TO A POTENTIALLY ACTIVE LATE WEEKEND/EARLY WORK WEEK SET
UP. BOTH ALSO INDICATE THE POTENTIAL OF A MYRIAD OF
PRECIPITATION...STARTING WITH TSTMS...SHOWERS...RAIN AND POSSIBLY
SNOW. WITH THE POTENTIAL SYSTEM STILL WAY OUT...DIDN/T WANT TO GET
TOO CUTE WITH PTYPE AND/OR LOCATIONS OF THE HIGHEST POPS. GENERALLY
BROAD-BRUSHED 30-40% POPS SUNDAY AND MONDAY...WITH SHOWERS POSSIBLY
CHANGING TO SNOW ACROSS THE NORTH LATE ON MONDAY...AND ACROSS THE
ENTIRE CWA EARLY TUESDAY MORNING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1238 PM CDT TUE APR 2 2013
NO AVIATION CONCERNS OVER THE NEXT 24 HOURS WITH VFR CONDITIONS
EXPECTED TO PREVAIL AT BOTH KLBF AND KVTN. WINDS WILL STRENGTHEN
OUT OF THE SOUTH TOMORROW MORNING...WITH WINDS GUSTING TO AROUND
20 KTS IN SOUTHERN NEBRASKA...TO AOA 25 KTS IN THE NORTH. CLOUD
COVER SHOULD GENERALLY STAY SOUTH OF THE AREA INTO KANSAS AND
COLORADO.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1221 PM CDT TUE APR 2 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 307 AM CDT TUE APR 2 2013
LATEST WATER VAPOR IMAGERY AND 500 MB RAP ANALYSIS SHOWED NORTHWEST
FLOW ALOFT ACROSS THE UPPER MISSISSIPPI RIVER VALLEY EARLY THIS
MORNING. A SHORTWAVE TROUGH WAS NOTED OVER SOUTHERN MANITOBA
RACING SOUTHEAST TOWARD THE AREA. SURFACE OBSERVATIONS INDICATED
HIGH PRESSURE STRETCHING FROM THE EASTERN DAKOTAS SOUTHEAST INTO
THE MIDDLE MISSISSIPPI RIVER VALLEY. THE HIGH WILL SLIDE EAST INTO
THE AREA TODAY. MEANWHILE THE SHORTWAVE TROUGH WILL MOVE THROUGH
BUT WILL DO LITTLE MORE THAN PRODUCE AN INCREASE IN CLOUD OVER
NORTHERN AND CENTRAL WISCONSIN WITH THE REST OF THE FORECAST AREA
EXPERIENCING MOSTLY SUNNY SKIES. PLAN ON HIGHS TODAY RANGING FROM
THE LOWER 30S OVER NORTHERN WISCONSIN TO THE UPPER 30S TO AROUND
40 ACROSS NORTHEAST IOWA. THE HIGH IS EXPECTED TO SLIDE OVER THE
AREA TONIGHT PROVIDING QUIET WEATHER. ANOTHER UNSEASONABLY COLD
NIGHT IS IN STORE FOR THE FORECAST AREA WITH LOWS FALLING INTO THE
UPPER TEENS TO LOWER 20S. FAVORED COLD SPOTS OVER NORTH CENTRAL
WISCONSIN...SUCH AS DIAMOND LAKE...COULD SEE LOWS FALL INTO THE
SINGLE DIGITS ABOVE ZERO.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 307 AM CDT TUE APR 2 2013
HIGH PRESSURE WILL CONTINUE TO DOMINATE THE WEATHER ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY ON WEDNESDAY WITH MOSTLY SUNNY SKIES
EXPECTED. THE SURFACE HIGH WILL SLIDE EAST LATE IN THE DAY AS A WEAK
COLD FRONT MOVES EAST OUT OF THE DAKOTAS. SOUTHERLY FLOW WILL
INCREASE ACROSS THE AREA AHEAD OF THIS FEATURE HELPING
TEMPERATURES WARM SLIGHTLY. PLAN ON HIGH TEMPERATURES RANGING FROM
THE LOWER 40S OVER NORTH CENTRAL WISCONSIN TO THE UPPER 40S TO
AROUND 50 ACROSS NORTHEAST IOWA. THE FRONT IS EXPECTED TO SAG
SOUTHEAST WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING AS A TROUGH
PUSHES EASTWARD ACROSS ONTARIO. FORECAST MODELS CONTINUE TO
GENERATE SOME LIGHT PRECIPITATION ALONG THE FRONT AS IT MOVES INTO
THE FORECAST AREA LATE WEDNESDAY NIGHT INTO THURSDAY MORNING.
FORCING IS NOT OVERLY IMPRESSIVE WITH THIS FEATURE WITH ONLY WEAK
ISENTROPIC LIFT NOTED. THE UPPER LEVEL FORCING IS PASSING WELL TO
THE NORTH OF THE REGION SO NOT EXPECTING MUCH PRECIPITATION.
HOWEVER...CANNOT RULE OUT SOME AREAS MEASURING SOME LIGHT RAIN MAINLY
ALONG AND NORTH OF INTESTATE 90. SOME SNOW COULD MIX IN EARLY IN
THE NORTH BEFORE TEMPERATURES WARM. HIGHS ON THURSDAY ARE EXPECTED
TO RANGE FROM LOWER TO MID 40S OVER NORTH CENTRAL WISCONSIN TO THE
LOWER 50S ACROSS NORTHEAST IOWA. THE FRONT WILL MOVE SOUTH AND
BECOME STATIONARY STRETCHING FROM THE WESTERN SOUTH DAKOTA EAST
THROUGH CENTRAL IOWA INTO NORTHERN ILLINOIS.
SURFACE HIGH PRESSURE IS EXPECTED TO RETURN BRIEFLY ON FRIDAY
PROVIDING ANOTHER QUIET DAY. MEANWHILE...A POTENT SHORTWAVE LOOKS TO
MOVE ACROSS THE PACIFIC NORTHWEST AND RACE EAST THROUGH THE DAKOTAS
LATE FRIDAY NIGHT. THE STATIONARY FRONT WILL LIFT NORTH AS THE WAVE
MOVES EAST AND ACT AS A BAROCLINIC ZONE. SURFACE LOW PRESSURE IS
EXPECTED TO DEVELOP ACROSS WESTERN SOUTH DAKOTA LATE FRIDAY
NIGHT...THEN MOVES EAST INTO THE UPPER MISSISSIPPI RIVER VALLEY
DURING THE DAY ON SATURDAY. STRONG 850 MB WARM AIR ADVECTION
DEVELOPS OVER THE AREA AHEAD OF THE APPROACHING LOW FRIDAY NIGHT
INTO SATURDAY MORNING. ISENTROPIC LIFT...ON THE 285-305K
SURFACES...INCREASES RAPIDLY AS THE LOW MOVES INTO THE AREA. THE
FORECAST MODELS HAVE BEEN SHOWING SOME DIFFERENCES REGARDING THE
PLACEMENT OF THE BOUNDARY WHICH WILL HAVE A HUGE IMPACT ON
PRECIPITATION TYPES. AT THIS TIME IT APPEARS THAT THE MAIN
PRECIPITATION TYPE WILL BE RAIN WITH PLENTY OF WARM AIR ADVECTING
NORTHWARD INTO THE REGION AHEAD OF THIS SYSTEM. THE PRECIPITATION
COULD START OUT AS SNOW EAST OF THE MISSISSIPPI RIVER LATE FRIDAY
NIGHT BUT SHOULD QUICKLY TRANSITION OVER TO ALL RAIN EARLY SATURDAY
MORNING. THE GEM AND GFS OFFER SIMILAR SOLUTIONS WITH THIS
SYSTEM...TAKING THE SURFACE LOW OVER SOUTHERN MINNESOTA ON SATURDAY
THEN ACROSS SOUTHERN WISCONSIN SATURDAY NIGHT. THE ECMWF OFFERS A
SLOWER AND MORE NORTHERLY SOLUTION...TAKING THE LOW OVER CENTRAL
MINNESOTA THROUGH NORTHERN WISCONSIN SATURDAY NIGHT. THE ECMWF
SOLUTION WOULD BRING MILD AIR INTO THE REGION ON SATURDAY...WITH
HIGHS CLIMBING INTO THE UPPER 50S TO LOWER 60S. ON THE OTHER HAND
THE GFS/GEM SOLUTION ARE ON THE COOLER SIDE WITH HIGHS RANGING
FROM THE UPPER 30S/LOWER 40S OVER NORTHERN WISCONSIN TO THE MID
50S ACROSS NORTHEAST IOWA. WILL LEAN TOWARDS A MODEL CONSENSUS
BLEND APPROACH. PLAN ON HIGHS RANGING FROM THE LOWER 40S OVER
NORTH CENTRAL WISCONSIN TO THE MID TO UPPER 50S SOUTH OF
INTERSTATE 90. THE LOW IS EXPECTED TO EXIT THE REGION ON SUNDAY.
AN ACTIVE PATTERN LOOKS TO DEVELOP MONDAY INTO TUESDAY AS A TROUGH
DIGS INTO THE SOUTHWEST CONUS. SOUTHWEST FLOW ALOFT COULD SET UP
OVER THE AREA. THE BAROCLINIC ZONE LOOKS TO REMAIN OVER THE UPPER
MIDWEST AS SHORTWAVE ENERGY EJECTS OUT OF OF THE SOUTHWEST FLOW
AND INTERACTS WITH IT. LATEST GUIDANCE SUGGESTS THE BOUNDARY WILL
STRETCH FROM NORTHERN OHIO WESTWARD THROUGH NORTHERN ILLINOIS
THROUGH SOUTHERN IOWA. WILL HAVE TO KEEP A CLOSE WATCH ON FUTURE
MODEL RUNS WITH THE POTENTIAL FOR THIS ACTIVE PATTERN TO BRING
SEVERAL ROUNDS OF PRECIPITATION TO THE REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1221 PM CDT TUE APR 2 2013
QUIET STRETCH OF VFR WEATHER TO CONTINUE. HIGH PRESSURE CURRENTLY
EXTENDING FROM MANITOBA INTO MISSOURI AND ILLINOIS WILL MOVE
SOUTHEAST THROUGH THE PERIOD AND BE CENTERED NEAR THE SOUTHERN TIP
OF LAKE MICHIGAN BY LATE WEDNESDAY MORNING. THE NORTHWEST WINDS
WILL DROP OFF AROUND SUNSET TO 5 KNOTS OR LESS AND THEN COME
AROUND THE SOUTH AFTER SUNRISE WEDNESDAY ONCE THE RIDGE AXIS GOES
BY. OTHER THAN A FEW MID LEVEL CLOUDS THIS AFTERNOON...LITTLE OR
NO CLOUDS EXPECTED THROUGH THE PERIOD.
&&
.HYDROLOGY...
ISSUED AT 307 AM CDT TUE APR 2 2013
THE COMBINATION OF SNOW MELT AND THE RAIN OVER THE WEEKEND HAS
RESULTED IN FLOODING ALONG THE TREMPEALEAU RIVER AT DODGE. THE
LATEST STAGE WAS 9.21FT. FLOOD STAGE IS 9FT. THE RIVER IS
EXPECTED TO CREST THIS MORNING AND THEN SLOWLY FALL LATE THIS
AFTERNOON INTO THIS EVENING.
THE BLACK RIVER HAS CRESTED BELOW FLOOD STAGE AT BLACK RIVER
FALLS. WITH PLENTY OF SNOW UPSTREAM...THIS RIVER WILL LIKELY STAY
HIGH FOR THE NEXT SEVERAL DAYS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
HYDROLOGY...WETENKAMP