Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/06/13
AREA FORECAST DISCUSSION
NWS TUCSON AZ
600 PM MST SUN MAY 5 2013
.SYNOPSIS...SHOWERS WILL SPREAD INTO THE AREA LATER TONIGHT INTO
EARLY MONDAY MORNING. PERIODS OF CLOUDS THROUGHOUT MUCH OF THE WEEK
AS LOW PRESSURE SETTLES IN OVER SOUTHERN ARIZONA. TEMPERATURES
RUNNING ABOUT SIX TO TEN DEGREES COOLER THAN AVERAGE. A FEW SHOWERS
POSSIBLE LATER IN THE WEEK AS WELL.
&&
.DISCUSSION...00Z KTWC SOUNDING CREPT BACK JUST ABOVE 1/2 INCH
PRECIPITABLE WATER FOR THE FIRST TIME IN A FEW WEEKS. HIGHER VALUES
LINING UP TO PUSH THIS WAY TONIGHT FROM THE SOUTH AND SOUTHWEST ON
BLENDED TOTAL PRECIPITABLE WATER IMAGERY. LATEST NAMDNG5 AND RAPID
REFRESH TRENDS CONTINUE TO ROTATE THE IMPULSE CURRENTLY NEAR THE
NORTHERN BAJA PENINSULA QUICKLY UNDER AND UP AHEAD OF THE
CONSOLIDATING LOW POSITION...THEN THROUGH SOUTHEAST ARIZONA AFTER
06Z. WE EARLIER ADJUSTED POP AND QPF TRENDS UP...WHILE NARROWING THE
WINDOW FOR THE MAIN FOCUS OF PRECIP CHANCES PRIMARILY BETWEEN
06Z-12Z FOR MOST OF SE AZ. HRRR CAPE IS ELEVATED TO A COUPLE OF
POCKETS ABOVE 500J AS THIS FEATURE PUSHES THROUGH SO A LIGHTNING
STRIKE OR TWO IS NOT OUT OF THE QUESTION.
&&
.PREV DISCUSSION...AS A LOW PRESSURE TROUGH SETTLES IN OVER THE
SOUTHWEST THE MOST NOTICEABLE CHANGE WILL BE THE COOLER
TEMPERATURES. HIGH TEMPERATURES HAVE BEEN AROUND 5 DEGREES ABOVE
AVERAGE AND WILL DROP TO 4-7 DEGREES BELOW AVERAGE ON MONDAY THROUGH
FRIDAY. OVERALL A 10 DEGREE DROP COMBINED WITH AN INCREASE IN
CLOUDINESS THROUGHOUT THE WEEK.
THE MOST DIFFICULT PORTION OF THE FORECAST FOR THIS WEEK IS THE
PROBABILITY OF PRECIPITATION. EXTENSIVE MOISTURE IS NOT ASSOCIATED
WITH THIS LOW PRESSURE. HENCE PRECIPITATION AMOUNTS WHEN THEY OCCUR
WILL LIKELY BE LESS THAN 0.10. MOST LOCATIONS THAT ARE FORTUNATE TO
RECEIVE PRECIPITATION WILL GET A HUNDREDTH OR TWO. GIVEN THIS
SITUATION HAVE KEPT POPS GENERALLY 30 PERCENT OR LESS. HIGHEST
PROBABILITY OF PRECIPITATION WILL BE IN THE HIGHER TERRAIN...WHICH
IS NORMAL. DAYS WITH THE HIGHEST CHANCE FOR PRECIPITATION ARE
TONIGHT INTO MONDAY MORNING AND FRIDAY. PICKING OUT PRECIPITATION
DETAILS PAST 24 HOURS IS DIFFICULT AND CONFIDENCE IS NOT HIGH WITH
THE TIMING OF ANY SHOWERS. CAPE IS ELEVATED SLIGHT OVER THE AREA
MONDAY AFTERNOON...AND HAVE KEPT A MENTION OF THUNDERSTORMS IN THE
FORECAST. BY NEXT WEEKEND...A RIDGE IS PROGGED TO BUILD OVER THE
SOUTHWEST FOR A RETURN TO ABOVE AVERAGE TEMPERATURES AND CLEAR SKIES.
&&
.AVIATION...SCT MID CLOUDS AT 12-16K FT AGL AND SCT-BKN HIGH CLOUDS
AOA 20K FT AGL THRU 06/03Z. MID CLOUDS THICKENING AND LOWERING AFT
06/03Z FROM WEST TO EAST...WITH SCT-BKN CLOUDS AT 7-10K FT AGL
BETWEEN 06/03Z AND 06/18Z. SLGT CHC -SHRA/-TSRA BETWEEN 06/04Z AND
06/18Z. SLY/SWLY SURFACE WIND AT 12-17 KTS WITH GUSTS TO 25-30 KTS
TIL 06/02Z. AFT 06/02Z...SURFACE WIND DIMINISHING...AND MAINLY LESS
THAN 10 KTS BY 06/08Z. SWLY SURFACE WIND INCREASING AGAIN AFT 06/16Z
TO 12-17 KTS AND HIGHER GUSTS. AVIATION DISCUSSION NOT UPDATED FOR
TAF AMENDMENTS.
&&
.FIRE WEATHER...COOLER TEMPERATURES ARE EXPECTED THROUGH THE END OF
THE UPCOMING WORK WEEK. THERE WILL BE A CHANCE OF SHOWERS TONIGHT
INTO MONDAY...ALONG WITH A POSSIBLE LIGHTNING STRIKE OR TWO. BREEZY
WINDS ARE ALSO EXPECTED THROUGH AT LEAST TUESDAY. WITH THE COOLER
TEMPERATURES AND CORRESPONDING INCREASES IN RELATIVE HUMIDITY
VALUES...CONDITIONS ARE EXPECTED TO REMAIN BELOW CRITICAL FIRE
WEATHER THRESHOLDS...EVEN THOUGH WINDS WILL BE STRONG AT TIMES
DURING THE AFTERNOON AND EARLY EVENING HOURS.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
MEYER
PREV DISCUSSION...GWS
AVIATION/FIRE WEATHER...ZELL
AREA FORECAST DISCUSSION
NWS POCATELLO ID
840 AM MDT SAT MAY 4 2013
.SHORT TERM...TODAY THROUGH TUESDAY. A QUICK UPDATE THIS MORNING TO
START THE LAKE WIND ADVISORY RIGHT AWAY THIS MORNING GIVEN THE
VERIFYING NE WINDS ALREADY BLOWING ACROSS THE AMERICAN FALLS
RESERVOIR. SEE PREVIOUS DISCUSSION BELOW. HUSTON
THUNDER WILL BE A CONCERN TODAY AS LAPSE RATES STEEPEN DURING THE
DAY. COLD AIR ALOFT ASSOCIATED WITH UPPER LOW WILL HELP DESTABILIZE
THE ATMOSPHERE AS WELL. IMPULSES OF ENERGY FROM THE UPPER LOW SHOULD
BE ENOUGH TO TRIGGER THE CONVECTION TODAY...AND IT IS PICKED UP
FAIRLY WELL BY THE HRRR AND WRF. EVEN MOS GUIDANCE IS ADVERTISING
FAIRLY HIGH THUNDER CHANCES. INFLUENCE OF THE UPPER LOW WILL ALSO BE
FELT TOMORROW AFTERNOON WITH THUNDER AGAIN IN THE FORECAST. MODELS
ARE ALSO HINTING AT A STRENGTHENING NORTHEASTERLY WIND THAT WILL
BRING AMERICAN FALLS RESERVOIR INTO LAKE WIND ADVISORY CRITERIA.
LOW-LEVEL LAPSE RATES AND BOUNDARY LAYER WINDS FAVOR THESE STRONGER
WINDS AS THE SURFACE GRADIENT TIGHTENS ACROSS THE AREA. MOS GUIDANCE
FOR KPIH SEEM A BIT ON THE LOW SIDE GIVEN THE CONDITIONS. HINSBERGER
.LONG TERM...TUESDAY THROUGH FRIDAY. THE CLOSED LOW THAT HAS
RETROGRADED TO THE CALIFORNIA COAST BEGINS TO REVERSE DIRECTION AND
MOVE INLAND. THE ECMWF TRACKS THE LOW TO SOUTH CENTRAL COLORADO BY
WEDNESDAY AFTERNOON WHILE THE GFS IS A LITTLE SLOWER AND MOVES THE
LOW MORE TOWARDS WEST CENTRAL COLORADO BY THE SAME TIME PERIOD. WRAP
AROUND MOISTURE EXTENDS ACROSS SOUTHEAST IDAHO BOTH TUESDAY AND
WEDNESDAY...THE GFS EXTENDS CONVECTION CLOSER TO THE MONTANA LINE.
MOISTURE HAS DEEPENED ENOUGH THAT CONVECTIVE SHOWERS COULD PRODUCE
.10 TO .20 INCH OF RAIN THAT WOULD BE MOSTLY NEEDED BUT PERHAPS
ACCELERATE SNOW RUN OFF FROM THE MOUNTAINS. AIR MASS IS UNSTABLE
ENOUGH FOR A SLIGHT CHANCE OF THUNDERSTORMS EACH DAY. THE LOW
CONTINUES TO MOVE EAST THURSDAY AND FRIDAY. THIS LEAVES SOUTHEAST
IDAHO UNDER NORTHWEST FLOW AND A HIGH PRESSURE RIDGE JUST OFF THE
WASHINGTON COAST. MOIST AIR LINGERS OVER THE FORECAST AREA WITH AND
MINOR DISTURBANCES PASSING TO THE NORTH THAT COULD CONTRIBUTE TO
ISOLATED SHOWERS IN THIS AREA. RS
&&
AVIATION...UPPER LOW THIS MORNING CENTERED ROUGHLY NEAR KSUN IN THE
PROCESS OF CLOSING OFF AND RETROGRADING TOWARDS THE CALIFORNIA COAST
THROUGH 05/06Z. SCATTERED RAIN SHOWERS FORMING IN BANDS AROUND THE
LOW AND WHERE TERRAIN FAVORED LIFT IS. SNOW LEVELS MAINLY NEAR 7200
FT MSL THIS MORNING INCREASING TO NEAR 7800 FT THIS AFTERNOON.
CEILINGS EXPECTED TO REMAIN VFR AT TAF SITES BUT WILL OBSCURE HIGHER
MOUNTAINS EVERYWHERE. CAN NOT RULE OUT AN ISOLATED THUNDERSTORM THIS
AFTERNOON. SOME STABILIZING OF SHOWERS TONIGHT AFTER 05/08Z...THEN
REDEVELOPING AFTER 05/18Z. RS
&&
.PIH WATCHES/WARNINGS/ADVISORIES...LAKE WIND ADVISORY UNTIL 9 PM MDT
THIS EVENING IDZ021.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
359 PM EDT SAT MAY 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 416 AM EDT SAT MAY 4 2013
AFTER BEING IN AN UNSETTLED WEATHER PATTERN FOR THE LAST SEVERAL
DAYS...THE AREA WILL TREND TOWARDS A DRIER PERIOD. WITH THE CUTOFF
LOW IS WELL TO OUR SOUTH AND THE NORTHERN STREAM JET FOCUSING
WELL NORTH INTO CANADA...THE AREA IS UNDER INCREASING UPPER LEVEL
RIDGING FROM THE RIDGE THAT HAS BEEN OVER EASTERN NORTH AMERICA.
THIS RIDGING...ALONG WITH SURFACE HIGH PRESSURE BUILDING OVER THE
UPPER GREAT LAKES WILL LEAD TO A DRIER AND WARMING TREND FOR THIS
WEEKEND.
THE FINAL PUSH FOR CENTRAL UPPER MICHIGAN IS CURRENTLY MOVING NNW
THIS MORNING AS THE 925MB WARM AIR ADVECTION SLOWLY PUSHES WEST.
FARTHER TO THE EAST...DRY MID LEVEL AIR SHOWN ON RAP ANALYSIS HAS
LED TO CLEAR SKIES OVER FAR EASTERN UPPER MICHIGAN ALONG THE
STALLED WARM FRONT AND ONLY MID TO HIGH CLOUDS OVER LAKE MICHIGAN
AND SOUTH CENTRAL UPPER MICHIGAN. LIGHT RAIN AND FREEZING RAIN IS
OCCURRING OVER THE FAR WEST...ALTHOUGH OBS AND RADAR ARE INDICATING
IT TO BE FAIRLY PATCHY. THERE ARE SOME STRONGER SHOWERS IN
SOUTHWEST WISCONSIN AND NORTHEAST IOWA...ASSOCIATED WITH SHORTWAVE
ENERGY PUSHING NORTHWEST THROUGH SOUTHWEST WISCONSIN AND THIS COULD
END UP BRUSHING THE FAR WESTERN CWA DURING THE AFTERNOON.
OTHERWISE...THE LIGHT PRECIPITATION OVER THE WEST WILL SLOWLY PUSH
OVER WESTERN LAKE SUPERIOR THROUGH THE DAY AND FALL AS RAIN WITH
THE 900-875MB TEMPS AROUND 8-9C. WITH LIGHT RAIN STILL OVER THE FAR
WEST AND TEMPERATURES BELOW FREEZING...WILL KEEP THE WINTER WEATHER
ADVISORY GOING UNTIL 12Z. ALL OF THE MODELS HAVE TEMPERATURES SLOWLY
RISING TO FREEZING OVER THE FAR WEST AT THAT TIME AND THEN SLOWLY
RISING ABOVE THAT AFTER SUNRISE. OTHERWISE...WITH THE LOW
LEVEL...SUB 900MB...NORTHEAST FLOW OVER THE WEST WILL KEEP THE LOW
CLOUDS IN PLACE THROUGH THE DAY.
THE DRIER AIR ALOFT SHOULD LEAD TO A DRY DAY ACROSS THE REST OF THE
CWA AND THE MAIN INFLUENCE ON THE WEATHER WILL BE THE LOCATION AND
DISSIPATION OF THE LOW CLOUDS OVER CENTRAL UPPER MICHIGAN. LATEST
TRENDS IN THE MODELS SHOW THAT THE LOW CLOUDS SHOULD DIMINISH
AROUND NOON OVER THE NORTH CENTRAL CWA. WITH THE EXPECTED LIGHT
NORTHERLY FLOW IN THE LOW LEVELS...NOT COMPLETELY CONFIDENT ON THAT
TIMING...SO ONLY WENT WITH PARTLY CLOUDY SKIES TOWARDS AFTERNOON.
BUT THE DRIER LOW LEVEL AIR TO THE SOUTHEAST...WONDERING IF THE
MODELS HAVE A HANDLE ON THE CLEARING IDEA AND THE FORECAST IS TOO
PESSIMISTIC. OTHERWISE...WOULD EXPECT MID-HIGH CLOUDS STREAMING
NORTHEAST ACROSS THE CENTRAL/EASTERN CWA THROUGH MUCH OF THE DAY.
AS FOR TEMPERATURES...EXPECT VALUES TO STRUGGLE TO REACH 40 OVER
THE FAR WEST UNDER THE CLOUDS. WITH THE BREAKS IN THE CLOUDS
OVER THE SOUTH CENTRAL AND EAST AND THE EXPECTED WESTWARD PUSH OF
THE 925/850MB TROUGH EARLY THIS MORNING AND THROUGH THE DAY ALLOWING
SOUTH-SOUTHEASTERLY FLOW TO DEVELOP OVER THE AREA...WOULD EXPECT
TEMPERATURES UNDER THE MAY SUN TO QUICKLY WARM INTO THE 50S/60S AND
A FEW LOWER 70S TOWARDS NEWBERRY. AS AN EXAMPLE...YESTERDAY WHERE
THE BREAKS IN THE CLOUDS WERE OVER THE EASTERN CWA...TEMPERATURES
WERE IN THE 50S AND LOWER 60S /DELTA...SCHOOLCRAFT...LUCE
COUNTIES/...BUT JUST TO THE WEST IN MARQUETTE COUNTY TEMPERATURES
WERE INN THE 30S. THUS...PINNING DOWN THE LOCATION/DISSIPATION OF
THE LOW CLOUDS CREATES A HUGE BUST POTENTIAL FOR HIGHS OVER THE
NORTH CENTRAL. NEAR LAKE SUPERIOR IN MARQUETTE COUNTY...THE NEAR
SURFACE FLOW WILL BE LIGHT AND NORTHERLY...WHICH WILL TRY TO KEEP
THE TEMPERATURES LOWER DUE TO LAKE SUPERIOR.
TONIGHT...HIGH PRESSURE CONTINUES TO BUILD OVER THE AREA...WHILE THE
925/850MB TROUGH DISSIPATES OVER EASTERN MINNESOTA AND FAR WESTERN
LAKE SUPERIOR. THIS SHOULD LEAD TO A DRY NIGHT ACROSS MUCH OF THE
AREA AND LIKE TODAY...THE CLOUDS WILL BE ONE OF THE MAIN FORECAST
CONCERNS. MODELS SHOWING THE LOW CLOUDS REMAINING OVER THE FAR WEST
WITH THE LINGERING NORTHEASTERLY FLOW THROUGH THE NIGHT. EXPECT THAT
TO BE THE CASE AND WILL KEEP CLOUDY SKIES THERE. IN
ADDITION...THERE MAY BE SOME LIGHT DRIZZLE/RAIN OVER THE FAR WEST
WITH THE LOW CLOUDS IN THE EVENING...BUT OVERALL MUCH OF THE
PRECIPITATION SHOULD HAVE DIMINISHED WITH THE WEAKENING FORCING OVER
THE WESTERN LAKE. THE SLIGHTLY UPSLOPE NORTHEAST FLOW OVER THE
WEST...HAVE ADDED A MENTION OF PATCHY FOG DUE TO THE LOW
CLOUDS INTERACTING WITH THE HIGHER TERRAIN.
OVER THE NORTH CENTRAL...MODELS ARE SHOWING THE LOWER CLOUDS
REDEVELOPING TONIGHT WITH THE LIGHT NORTHERLY FLOW AND LINGERING LOW
LEVEL MOISTURE. WILL GO WITH A PARTLY-MOSTLY CLOUDY SKY AND THEN
DIMINISH IT HEADING SOUTH TOWARDS IRON MOUNTAIN. ALSO ADDED A
MENTION OF FOG TO THE HIGHER TERRAIN LOCATIONS.
FARTHER EAST AND AWAY FROM LAKE SUPERIOR...EXPECT MOSTLY CLEAR
SKIES WITH A SLIM POTENTIAL FOR FOG DUE TO THE EXPECTED MIXING OUT
TODAY AND DRIER AIR IN PLACE. THE FOG POTENTIAL WILL LIKELY DEPEND
ON IF FOG DEVELOPS OVER EASTERN LAKE SUPERIOR TODAY. IF IT
DOES...THE LIGHT NORTHERLY WINDS WILL DRAG IT SOUTH INTO THE
EASTERN CWA. DON/T HAVE THE CONFIDENCE TO ADD AT THIS POINT AND IT
WILL BE SOMETHING FOR THE DAY SHIFT TO WATCH.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 416 AM EDT SAT MAY 4 2013
SUN...SFC HI PRES SINKING SLOWLY S FM ONTARIO WL SHIFT OVER LK SUP
BY LATE IN THE DAY UNDER UPR RDG AXIS TO THE N OF CLOSED LO SHIFTING
INTO THE SE CONUS. WITH THE ARRIVAL OF MORE ACYC FLOW/FRONTOLYSIS OF
LINGERING STNRY FNT AS WELL AS DIRUNAL HEATING...EXPECT MRNG LO CLDS
OVER THE NCENTRAL AND W TO SLOWLY DSPT. THESE CLDS WL BE MOST
PERSISTENT OVER THE HIER TERRAIN OF THE W WHERE LLVL MSTR IS A BIT
GREATER AND HOLD DOWN MAX TEMP RECOVERY WITH LLVL N WIND OFF LK SUP.
WL TEND TOWARD THE LOWER END OF GUIDANCE FOR TEMPS OVER THE NCENTRAL
AND W. MORE SUNSHINE OVER THE SCENTRAL AND E WITH H85 TEMPS UP TO
8-9C SHOULD ALLOW A SHARP CONTRAST TO THIS COOLER WX. EXPECT MAX
TEMPS UP TO 70 PER MIXING TO H85 ON FCST SDNGS AWAY FM THE LK
BREEZES THAT WL FORM IN PRESENCE OF WEAK GRADIENT ASSOCIATED WITH
THE HI.
SUN NGT THRU TUE...EXPECT DRY WX TO PREVAIL WITH NEAR STNRY HI PRES
UNDER UPR RDG AXIS EXTENDING E-W ACRS THE UPR LKS. ALTHOUGH H85
TEMPS ARE FCST TO REMAIN NEAR 8C...EXPECT A SLOW WARMING TREND AS
THE LLVLS SLOWLY MODERATE WITH HI SOLAR ANGLE. BUT WEAK PRES
GRADIENT UNDER THE SFC HI WL ALLOW LK BREEZES TO DVLP AND KEEP LK
SHORE COMMUNITIES COOLER. SOME MODELS GENERATE LGT QPF DURING THE
AFTNS WITH THE DAYTIME HEATING/LK BREEZE BNDRYS/LINGERING LLVL
MSTR...BUT WL NOT INCLUDE POPS ATTM GIVEN LARGE SCALE ACYC FLOW.
SUSPECT THERE WL BE QUITE A BIT OF DIURNAL CU. ALTHOUGH LGT WINDS WL
ALLOW FOR EFFICIENT RADIATIONAL COOLING...FCST PWATS REMAIN FAIRLY
HI ESPECIALLY OVER THE NW HALF. THE SHARPEST DIURNAL TEMP FALLS AT
NGT SHOULD BE OVER THE SCENTRAL AND E CLOSER TO THE CORE OF DRIER
AIR. OPTED TO INCLUDE A MENTION OF PATCHY FOG OVER THE INTERIOR WITH
THE LGT WINDS/FAIRLY SUBSTANTIAL LLVL MSTR.
TUE NGT INTO THU...APRCH OF WEAK SHRTWV FM THE W THAT WEAKENS RDG
OVER THE UPR LKS AND APRCH OF COLD FNT DROPPING S THRU ONTARIO ON
THE SRN FLANK OF DEEPENING UPR TROF CENTERED OVER HUDSON BAY WL
ALLOW A RETURN OF SOME -SHRA. SUSPECT THE BEST CHC FOR THESE SHRA WL
BE DURING THE DAY ON WED...WHEN DIURNAL HEATING WL BE IN PHASE WITH
DYNAMICS AHEAD OF THE APRCHG SHRTWV.
LATER THU THRU FRI...EXPECT A COOLING/DRYING TREND WITH N-NE WIND ON
THE SRN FLANK OF HI PRES BLDG INTO/THRU ONTARIO AND FCST H85 TEMPS
NEAR 0C BY FRI UNDER SLOWLY DEEPENING UPR TROF ACRS THE E HALF OF
NAMERICA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 151 PM EDT SAT MAY 4 2013
THE THICK DECK OF LOW CLOUDS SET UP OVER FAR WESTERN UPPER MI
CONTINUES TO EXIT EASTWARD...THANKS TO DRIER AIR AND DAYTIME
HEATING. EXPECT THE LOW CLOUDS AND FOG TO DEVELOP ONCE AGAIN TONIGHT
/NEARING IFR/...PARTICULARLY WHERE LOW LEVEL MOISTURE REMAINS
HIGH...OVER THE WESTERN TAF SITE OF IWD. LIGHT WINDS WILL BE THE
RULE AS A LARGE AREA OF HIGH PRESSURE SINKS IN FROM CENTRAL
ONTARIO...AND RESIDES OVER THE AREA BY MID AFTERNOON SUNDAY. MAINLY
DRY WEATHER /ALTHOUGH WITH PLENTY OF CLOUDS/ AND EARLY MORNING LAKE
BREEZES WILL BE COMMON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 416 AM EDT SAT MAY 4 2013
EXPECT N WINDS UP TO 20 KTS EARLY THIS MORNING TO DIMINISH THRU
TODAY/TONIGHT WITH APPROACH OF HI PRES FROM NW ONTARIO. WINDS WILL
THEN REMAIN LIGHT THRU NEXT WED WITH HI PRES/WEAK PRES GRADIENT
DOMINATING THE UPPER GREAT LAKES.
&&
.HYDROLOGY...
ISSUED AT 416 AM EDT SAT MAY 4 2013
THE STURGEON RIVER AT ALSTON AND CHASSELL...THE MICHIGAMME RIVER
AROUND WITCH LAKE...AND THE PAINT RIVER NEAR CRYSTAL FALLS WILL
REMAIN CONCERNS INTO AT LEAST EARLY NEXT WEEK...AND IN THE CASE OF
THE MICHIGAMME RIVER PERHAPS WELL INTO THE COMING WEEK. BUT
OTHERWISE RIVER LEVELS CONTINUE TO COME DOWN DESPITE SOME RECENT
HEAVY PRECIP THAT IMPACTED MAINLY THE W HALF OF UPR MI. IN FACT...A
DECENT AMOUNT OF WATER EQUIVALENT HAS OCCURRED SINCE THU OVER THE
WESTERN CWA...VCNTY OF IRONWOOD TO ONTONAGON...WITH OVER 2 INCHES
OVER FAR WESTERN GOGEBIC COUNTY. WILL HAVE TO ASSESS WHAT AFFECT THE
PRECIP WILL HAVE WHEN COMBINED WITH FURTHER MELTING OF ANY SUSTAINED
SNOWPACK WHEN TEMPS WARM SUN INTO NEXT WEEK. SNOW WATER EQUIVALENT
OF 8.8 INCHES IN PAINESDALE IN HOUGHTON COUNTY ON THURSDAY WITH 24
INCHES OF SNOW DEPTH...SO THE OTTER RIVER STILL HAS PLENTY OF SNOW
IN THE HEADWATERS WHICH MAY CAUSE ADDITIONAL PROBELMS AT CLLM4 IN
THE COMING DAYS.
FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD WARNINGS AND
ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KC
AVIATION...KF
MARINE...KC
HYDROLOGY...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
151 PM EDT SAT MAY 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 416 AM EDT SAT MAY 4 2013
AFTER BEING IN AN UNSETTLED WEATHER PATTERN FOR THE LAST SEVERAL
DAYS...THE AREA WILL TREND TOWARDS A DRIER PERIOD. WITH THE CUTOFF
LOW IS WELL TO OUR SOUTH AND THE NORTHERN STREAM JET FOCUSING
WELL NORTH INTO CANADA...THE AREA IS UNDER INCREASING UPPER LEVEL
RIDGING FROM THE RIDGE THAT HAS BEEN OVER EASTERN NORTH AMERICA.
THIS RIDGING...ALONG WITH SURFACE HIGH PRESSURE BUILDING OVER THE
UPPER GREAT LAKES WILL LEAD TO A DRIER AND WARMING TREND FOR THIS
WEEKEND.
THE FINAL PUSH FOR CENTRAL UPPER MICHIGAN IS CURRENTLY MOVING NNW
THIS MORNING AS THE 925MB WARM AIR ADVECTION SLOWLY PUSHES WEST.
FARTHER TO THE EAST...DRY MID LEVEL AIR SHOWN ON RAP ANALYSIS HAS
LED TO CLEAR SKIES OVER FAR EASTERN UPPER MICHIGAN ALONG THE
STALLED WARM FRONT AND ONLY MID TO HIGH CLOUDS OVER LAKE MICHIGAN
AND SOUTH CENTRAL UPPER MICHIGAN. LIGHT RAIN AND FREEZING RAIN IS
OCCURRING OVER THE FAR WEST...ALTHOUGH OBS AND RADAR ARE INDICATING
IT TO BE FAIRLY PATCHY. THERE ARE SOME STRONGER SHOWERS IN
SOUTHWEST WISCONSIN AND NORTHEAST IOWA...ASSOCIATED WITH SHORTWAVE
ENERGY PUSHING NORTHWEST THROUGH SOUTHWEST WISCONSIN AND THIS COULD
END UP BRUSHING THE FAR WESTERN CWA DURING THE AFTERNOON.
OTHERWISE...THE LIGHT PRECIPITATION OVER THE WEST WILL SLOWLY PUSH
OVER WESTERN LAKE SUPERIOR THROUGH THE DAY AND FALL AS RAIN WITH
THE 900-875MB TEMPS AROUND 8-9C. WITH LIGHT RAIN STILL OVER THE FAR
WEST AND TEMPERATURES BELOW FREEZING...WILL KEEP THE WINTER WEATHER
ADVISORY GOING UNTIL 12Z. ALL OF THE MODELS HAVE TEMPERATURES SLOWLY
RISING TO FREEZING OVER THE FAR WEST AT THAT TIME AND THEN SLOWLY
RISING ABOVE THAT AFTER SUNRISE. OTHERWISE...WITH THE LOW
LEVEL...SUB 900MB...NORTHEAST FLOW OVER THE WEST WILL KEEP THE LOW
CLOUDS IN PLACE THROUGH THE DAY.
THE DRIER AIR ALOFT SHOULD LEAD TO A DRY DAY ACROSS THE REST OF THE
CWA AND THE MAIN INFLUENCE ON THE WEATHER WILL BE THE LOCATION AND
DISSIPATION OF THE LOW CLOUDS OVER CENTRAL UPPER MICHIGAN. LATEST
TRENDS IN THE MODELS SHOW THAT THE LOW CLOUDS SHOULD DIMINISH
AROUND NOON OVER THE NORTH CENTRAL CWA. WITH THE EXPECTED LIGHT
NORTHERLY FLOW IN THE LOW LEVELS...NOT COMPLETELY CONFIDENT ON THAT
TIMING...SO ONLY WENT WITH PARTLY CLOUDY SKIES TOWARDS AFTERNOON.
BUT THE DRIER LOW LEVEL AIR TO THE SOUTHEAST...WONDERING IF THE
MODELS HAVE A HANDLE ON THE CLEARING IDEA AND THE FORECAST IS TOO
PESSIMISTIC. OTHERWISE...WOULD EXPECT MID-HIGH CLOUDS STREAMING
NORTHEAST ACROSS THE CENTRAL/EASTERN CWA THROUGH MUCH OF THE DAY.
AS FOR TEMPERATURES...EXPECT VALUES TO STRUGGLE TO REACH 40 OVER
THE FAR WEST UNDER THE CLOUDS. WITH THE BREAKS IN THE CLOUDS
OVER THE SOUTH CENTRAL AND EAST AND THE EXPECTED WESTWARD PUSH OF
THE 925/850MB TROUGH EARLY THIS MORNING AND THROUGH THE DAY ALLOWING
SOUTH-SOUTHEASTERLY FLOW TO DEVELOP OVER THE AREA...WOULD EXPECT
TEMPERATURES UNDER THE MAY SUN TO QUICKLY WARM INTO THE 50S/60S AND
A FEW LOWER 70S TOWARDS NEWBERRY. AS AN EXAMPLE...YESTERDAY WHERE
THE BREAKS IN THE CLOUDS WERE OVER THE EASTERN CWA...TEMPERATURES
WERE IN THE 50S AND LOWER 60S /DELTA...SCHOOLCRAFT...LUCE
COUNTIES/...BUT JUST TO THE WEST IN MARQUETTE COUNTY TEMPERATURES
WERE INN THE 30S. THUS...PINNING DOWN THE LOCATION/DISSIPATION OF
THE LOW CLOUDS CREATES A HUGE BUST POTENTIAL FOR HIGHS OVER THE
NORTH CENTRAL. NEAR LAKE SUPERIOR IN MARQUETTE COUNTY...THE NEAR
SURFACE FLOW WILL BE LIGHT AND NORTHERLY...WHICH WILL TRY TO KEEP
THE TEMPERATURES LOWER DUE TO LAKE SUPERIOR.
TONIGHT...HIGH PRESSURE CONTINUES TO BUILD OVER THE AREA...WHILE THE
925/850MB TROUGH DISSIPATES OVER EASTERN MINNESOTA AND FAR WESTERN
LAKE SUPERIOR. THIS SHOULD LEAD TO A DRY NIGHT ACROSS MUCH OF THE
AREA AND LIKE TODAY...THE CLOUDS WILL BE ONE OF THE MAIN FORECAST
CONCERNS. MODELS SHOWING THE LOW CLOUDS REMAINING OVER THE FAR WEST
WITH THE LINGERING NORTHEASTERLY FLOW THROUGH THE NIGHT. EXPECT THAT
TO BE THE CASE AND WILL KEEP CLOUDY SKIES THERE. IN
ADDITION...THERE MAY BE SOME LIGHT DRIZZLE/RAIN OVER THE FAR WEST
WITH THE LOW CLOUDS IN THE EVENING...BUT OVERALL MUCH OF THE
PRECIPITATION SHOULD HAVE DIMINISHED WITH THE WEAKENING FORCING OVER
THE WESTERN LAKE. THE SLIGHTLY UPSLOPE NORTHEAST FLOW OVER THE
WEST...HAVE ADDED A MENTION OF PATCHY FOG DUE TO THE LOW
CLOUDS INTERACTING WITH THE HIGHER TERRAIN.
OVER THE NORTH CENTRAL...MODELS ARE SHOWING THE LOWER CLOUDS
REDEVELOPING TONIGHT WITH THE LIGHT NORTHERLY FLOW AND LINGERING LOW
LEVEL MOISTURE. WILL GO WITH A PARTLY-MOSTLY CLOUDY SKY AND THEN
DIMINISH IT HEADING SOUTH TOWARDS IRON MOUNTAIN. ALSO ADDED A
MENTION OF FOG TO THE HIGHER TERRAIN LOCATIONS.
FARTHER EAST AND AWAY FROM LAKE SUPERIOR...EXPECT MOSTLY CLEAR
SKIES WITH A SLIM POTENTIAL FOR FOG DUE TO THE EXPECTED MIXING OUT
TODAY AND DRIER AIR IN PLACE. THE FOG POTENTIAL WILL LIKELY DEPEND
ON IF FOG DEVELOPS OVER EASTERN LAKE SUPERIOR TODAY. IF IT
DOES...THE LIGHT NORTHERLY WINDS WILL DRAG IT SOUTH INTO THE
EASTERN CWA. DON/T HAVE THE CONFIDENCE TO ADD AT THIS POINT AND IT
WILL BE SOMETHING FOR THE DAY SHIFT TO WATCH.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 416 AM EDT SAT MAY 4 2013
SUN...SFC HI PRES SINKING SLOWLY S FM ONTARIO WL SHIFT OVER LK SUP
BY LATE IN THE DAY UNDER UPR RDG AXIS TO THE N OF CLOSED LO SHIFTING
INTO THE SE CONUS. WITH THE ARRIVAL OF MORE ACYC FLOW/FRONTOLYSIS OF
LINGERING STNRY FNT AS WELL AS DIRUNAL HEATING...EXPECT MRNG LO CLDS
OVER THE NCENTRAL AND W TO SLOWLY DSPT. THESE CLDS WL BE MOST
PERSISTENT OVER THE HIER TERRAIN OF THE W WHERE LLVL MSTR IS A BIT
GREATER AND HOLD DOWN MAX TEMP RECOVERY WITH LLVL N WIND OFF LK SUP.
WL TEND TOWARD THE LOWER END OF GUIDANCE FOR TEMPS OVER THE NCENTRAL
AND W. MORE SUNSHINE OVER THE SCENTRAL AND E WITH H85 TEMPS UP TO
8-9C SHOULD ALLOW A SHARP CONTRAST TO THIS COOLER WX. EXPECT MAX
TEMPS UP TO 70 PER MIXING TO H85 ON FCST SDNGS AWAY FM THE LK
BREEZES THAT WL FORM IN PRESENCE OF WEAK GRADIENT ASSOCIATED WITH
THE HI.
SUN NGT THRU TUE...EXPECT DRY WX TO PREVAIL WITH NEAR STNRY HI PRES
UNDER UPR RDG AXIS EXTENDING E-W ACRS THE UPR LKS. ALTHOUGH H85
TEMPS ARE FCST TO REMAIN NEAR 8C...EXPECT A SLOW WARMING TREND AS
THE LLVLS SLOWLY MODERATE WITH HI SOLAR ANGLE. BUT WEAK PRES
GRADIENT UNDER THE SFC HI WL ALLOW LK BREEZES TO DVLP AND KEEP LK
SHORE COMMUNITIES COOLER. SOME MODELS GENERATE LGT QPF DURING THE
AFTNS WITH THE DAYTIME HEATING/LK BREEZE BNDRYS/LINGERING LLVL
MSTR...BUT WL NOT INCLUDE POPS ATTM GIVEN LARGE SCALE ACYC FLOW.
SUSPECT THERE WL BE QUITE A BIT OF DIURNAL CU. ALTHOUGH LGT WINDS WL
ALLOW FOR EFFICIENT RADIATIONAL COOLING...FCST PWATS REMAIN FAIRLY
HI ESPECIALLY OVER THE NW HALF. THE SHARPEST DIURNAL TEMP FALLS AT
NGT SHOULD BE OVER THE SCENTRAL AND E CLOSER TO THE CORE OF DRIER
AIR. OPTED TO INCLUDE A MENTION OF PATCHY FOG OVER THE INTERIOR WITH
THE LGT WINDS/FAIRLY SUBSTANTIAL LLVL MSTR.
TUE NGT INTO THU...APRCH OF WEAK SHRTWV FM THE W THAT WEAKENS RDG
OVER THE UPR LKS AND APRCH OF COLD FNT DROPPING S THRU ONTARIO ON
THE SRN FLANK OF DEEPENING UPR TROF CENTERED OVER HUDSON BAY WL
ALLOW A RETURN OF SOME -SHRA. SUSPECT THE BEST CHC FOR THESE SHRA WL
BE DURING THE DAY ON WED...WHEN DIURNAL HEATING WL BE IN PHASE WITH
DYNAMICS AHEAD OF THE APRCHG SHRTWV.
LATER THU THRU FRI...EXPECT A COOLING/DRYING TREND WITH N-NE WIND ON
THE SRN FLANK OF HI PRES BLDG INTO/THRU ONTARIO AND FCST H85 TEMPS
NEAR 0C BY FRI UNDER SLOWLY DEEPENING UPR TROF ACRS THE E HALF OF
NAMERICA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 151 PM EDT SAT MAY 4 2013
THE THICK DECK OF LOW CLOUDS SET UP OVER FAR WESTERN UPPER MI
CONTINUES TO EXIT EASTWARD...THANKS TO DRIER AIR AND DAYTIME
HEATING. EXPECT THE LOW CLOUDS AND FOG TO DEVELOP ONCE AGAIN TONIGHT
/NEARING IFR/...PARTICULARLY WHERE LOW LEVEL MOISTURE REMAINS
HIGH...OVER THE WESTERN TAF SITE OF IWD. LIGHT WINDS WILL BE THE
RULE AS A LARGE AREA OF HIGH PRESSURE SINKS IN FROM CENTRAL
ONTARIO...AND RESIDES OVER THE AREA BY MID AFTERNOON SUNDAY. MAINLY
DRY WEATHER /ALTHOUGH WITH PLENTY OF CLOUDS/ AND EARLY MORNING LAKE
BREEZES WILL BE COMMON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 416 AM EDT SAT MAY 4 2013
EXPECT N WINDS UP TO 20 KTS EARLY THIS MORNING TO DIMINISH THRU
TODAY/TONIGHT WITH APPROACH OF HI PRES FROM NW ONTARIO. WINDS WILL
THEN REMAIN LIGHT THRU NEXT WED WITH HI PRES/WEAK PRES GRADIENT
DOMINATING THE UPPER GREAT LAKES.
&&
.HYDROLOGY...
ISSUED AT 416 AM EDT SAT MAY 4 2013
THE STURGEON RIVER AT ALSTON AND CHASSELL...THE MICHIGAMME RIVER
AROUND WITCH LAKE...AND THE PAINT RIVER NEAR CRYSTAL FALLS WILL
REMAIN CONCERNS INTO AT LEAST EARLY NEXT WEEK...AND IN THE CASE OF
THE MICHIGAMME RIVER PERHAPS WELL INTO THE COMING WEEK. BUT
OTHERWISE RIVER LEVELS CONTINUE TO COME DOWN DESPITE SOME RECENT
HEAVY PRECIP THAT IMPACTED MAINLY THE W HALF OF UPR MI. IN FACT...A
DECENT AMOUNT OF WATER EQUIVALENT HAS OCCURRED SINCE THU OVER THE
WESTERN CWA...VCNTY OF IRONWOOD TO ONTONAGON...WITH OVER 2 INCHES
OVER FAR WESTERN GOGEBIC COUNTY. WILL HAVE TO ASSESS WHAT AFFECT THE
PRECIP WILL HAVE WHEN COMBINED WITH FURTHER MELTING OF ANY SUSTAINED
SNOWPACK WHEN TEMPS WARM SUN INTO NEXT WEEK. SNOW WATER EQUIVALENT
OF 8.8 INCHES IN PAINESDALE IN HOUGHTON COUNTY ON THURSDAY WITH 24
INCHES OF SNOW DEPTH...SO THE OTTER RIVER STILL HAS PLENTY OF SNOW
IN THE HEADWATERS WHICH MAY CAUSE ADDITIONAL PROBELMS AT CLLM4 IN
THE COMING DAYS.
FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD WARNINGS AND
ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KC
AVIATION...KF
MARINE...KC
HYDROLOGY...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
749 AM EDT SAT MAY 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 416 AM EDT SAT MAY 4 2013
AFTER BEING IN AN UNSETTLED WEATHER PATTERN FOR THE LAST SEVERAL
DAYS...THE AREA WILL TREND TOWARDS A DRIER PERIOD. WITH THE CUTOFF
LOW IS WELL TO OUR SOUTH AND THE NORTHERN STREAM JET FOCUSING
WELL NORTH INTO CANADA...THE AREA IS UNDER INCREASING UPPER LEVEL
RIDGING FROM THE RIDGE THAT HAS BEEN OVER EASTERN NORTH AMERICA.
THIS RIDGING...ALONG WITH SURFACE HIGH PRESSURE BUILDING OVER THE
UPPER GREAT LAKES WILL LEAD TO A DRIER AND WARMING TREND FOR THIS
WEEKEND.
THE FINAL PUSH FOR CENTRAL UPPER MICHIGAN IS CURRENTLY MOVING NNW
THIS MORNING AS THE 925MB WARM AIR ADVECTION SLOWLY PUSHES WEST.
FARTHER TO THE EAST...DRY MID LEVEL AIR SHOWN ON RAP ANALYSIS HAS
LED TO CLEAR SKIES OVER FAR EASTERN UPPER MICHIGAN ALONG THE
STALLED WARM FRONT AND ONLY MID TO HIGH CLOUDS OVER LAKE MICHIGAN
AND SOUTH CENTRAL UPPER MICHIGAN. LIGHT RAIN AND FREEZING RAIN IS
OCCURRING OVER THE FAR WEST...ALTHOUGH OBS AND RADAR ARE INDICATING
IT TO BE FAIRLY PATCHY. THERE ARE SOME STRONGER SHOWERS IN
SOUTHWEST WISCONSIN AND NORTHEAST IOWA...ASSOCIATED WITH SHORTWAVE
ENERGY PUSHING NORTHWEST THROUGH SOUTHWEST WISCONSIN AND THIS COULD
END UP BRUSHING THE FAR WESTERN CWA DURING THE AFTERNOON.
OTHERWISE...THE LIGHT PRECIPITATION OVER THE WEST WILL SLOWLY PUSH
OVER WESTERN LAKE SUPERIOR THROUGH THE DAY AND FALL AS RAIN WITH
THE 900-875MB TEMPS AROUND 8-9C. WITH LIGHT RAIN STILL OVER THE FAR
WEST AND TEMPERATURES BELOW FREEZING...WILL KEEP THE WINTER WEATHER
ADVISORY GOING UNTIL 12Z. ALL OF THE MODELS HAVE TEMPERATURES SLOWLY
RISING TO FREEZING OVER THE FAR WEST AT THAT TIME AND THEN SLOWLY
RISING ABOVE THAT AFTER SUNRISE. OTHERWISE...WITH THE LOW
LEVEL...SUB 900MB...NORTHEAST FLOW OVER THE WEST WILL KEEP THE LOW
CLOUDS IN PLACE THROUGH THE DAY.
THE DRIER AIR ALOFT SHOULD LEAD TO A DRY DAY ACROSS THE REST OF THE
CWA AND THE MAIN INFLUENCE ON THE WEATHER WILL BE THE LOCATION AND
DISSIPATION OF THE LOW CLOUDS OVER CENTRAL UPPER MICHIGAN. LATEST
TRENDS IN THE MODELS SHOW THAT THE LOW CLOUDS SHOULD DIMINISH
AROUND NOON OVER THE NORTH CENTRAL CWA. WITH THE EXPECTED LIGHT
NORTHERLY FLOW IN THE LOW LEVELS...NOT COMPLETELY CONFIDENT ON THAT
TIMING...SO ONLY WENT WITH PARTLY CLOUDY SKIES TOWARDS AFTERNOON.
BUT THE DRIER LOW LEVEL AIR TO THE SOUTHEAST...WONDERING IF THE
MODELS HAVE A HANDLE ON THE CLEARING IDEA AND THE FORECAST IS TOO
PESSIMISTIC. OTHERWISE...WOULD EXPECT MID-HIGH CLOUDS STREAMING
NORTHEAST ACROSS THE CENTRAL/EASTERN CWA THROUGH MUCH OF THE DAY.
AS FOR TEMPERATURES...EXPECT VALUES TO STRUGGLE TO REACH 40 OVER
THE FAR WEST UNDER THE CLOUDS. WITH THE BREAKS IN THE CLOUDS
OVER THE SOUTH CENTRAL AND EAST AND THE EXPECTED WESTWARD PUSH OF
THE 925/850MB TROUGH EARLY THIS MORNING AND THROUGH THE DAY ALLOWING
SOUTH-SOUTHEASTERLY FLOW TO DEVELOP OVER THE AREA...WOULD EXPECT
TEMPERATURES UNDER THE MAY SUN TO QUICKLY WARM INTO THE 50S/60S AND
A FEW LOWER 70S TOWARDS NEWBERRY. AS AN EXAMPLE...YESTERDAY WHERE
THE BREAKS IN THE CLOUDS WERE OVER THE EASTERN CWA...TEMPERATURES
WERE IN THE 50S AND LOWER 60S /DELTA...SCHOOLCRAFT...LUCE
COUNTIES/...BUT JUST TO THE WEST IN MARQUETTE COUNTY TEMPERATURES
WERE INN THE 30S. THUS...PINNING DOWN THE LOCATION/DISSIPATION OF
THE LOW CLOUDS CREATES A HUGE BUST POTENTIAL FOR HIGHS OVER THE
NORTH CENTRAL. NEAR LAKE SUPERIOR IN MARQUETTE COUNTY...THE NEAR
SURFACE FLOW WILL BE LIGHT AND NORTHERLY...WHICH WILL TRY TO KEEP
THE TEMPERATURES LOWER DUE TO LAKE SUPERIOR.
TONIGHT...HIGH PRESSURE CONTINUES TO BUILD OVER THE AREA...WHILE THE
925/850MB TROUGH DISSIPATES OVER EASTERN MINNESOTA AND FAR WESTERN
LAKE SUPERIOR. THIS SHOULD LEAD TO A DRY NIGHT ACROSS MUCH OF THE
AREA AND LIKE TODAY...THE CLOUDS WILL BE ONE OF THE MAIN FORECAST
CONCERNS. MODELS SHOWING THE LOW CLOUDS REMAINING OVER THE FAR WEST
WITH THE LINGERING NORTHEASTERLY FLOW THROUGH THE NIGHT. EXPECT THAT
TO BE THE CASE AND WILL KEEP CLOUDY SKIES THERE. IN
ADDITION...THERE MAY BE SOME LIGHT DRIZZLE/RAIN OVER THE FAR WEST
WITH THE LOW CLOUDS IN THE EVENING...BUT OVERALL MUCH OF THE
PRECIPITATION SHOULD HAVE DIMINISHED WITH THE WEAKENING FORCING OVER
THE WESTERN LAKE. THE SLIGHTLY UPSLOPE NORTHEAST FLOW OVER THE
WEST...HAVE ADDED A MENTION OF PATCHY FOG DUE TO THE LOW
CLOUDS INTERACTING WITH THE HIGHER TERRAIN.
OVER THE NORTH CENTRAL...MODELS ARE SHOWING THE LOWER CLOUDS
REDEVELOPING TONIGHT WITH THE LIGHT NORTHERLY FLOW AND LINGERING LOW
LEVEL MOISTURE. WILL GO WITH A PARTLY-MOSTLY CLOUDY SKY AND THEN
DIMINISH IT HEADING SOUTH TOWARDS IRON MOUNTAIN. ALSO ADDED A
MENTION OF FOG TO THE HIGHER TERRAIN LOCATIONS.
FARTHER EAST AND AWAY FROM LAKE SUPERIOR...EXPECT MOSTLY CLEAR
SKIES WITH A SLIM POTENTIAL FOR FOG DUE TO THE EXPECTED MIXING OUT
TODAY AND DRIER AIR IN PLACE. THE FOG POTENTIAL WILL LIKELY DEPEND
ON IF FOG DEVELOPS OVER EASTERN LAKE SUPERIOR TODAY. IF IT
DOES...THE LIGHT NORTHERLY WINDS WILL DRAG IT SOUTH INTO THE
EASTERN CWA. DON/T HAVE THE CONFIDENCE TO ADD AT THIS POINT AND IT
WILL BE SOMETHING FOR THE DAY SHIFT TO WATCH.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 416 AM EDT SAT MAY 4 2013
SUN...SFC HI PRES SINKING SLOWLY S FM ONTARIO WL SHIFT OVER LK SUP
BY LATE IN THE DAY UNDER UPR RDG AXIS TO THE N OF CLOSED LO SHIFTING
INTO THE SE CONUS. WITH THE ARRIVAL OF MORE ACYC FLOW/FRONTOLYSIS OF
LINGERING STNRY FNT AS WELL AS DIRUNAL HEATING...EXPECT MRNG LO CLDS
OVER THE NCENTRAL AND W TO SLOWLY DSPT. THESE CLDS WL BE MOST
PERSISTENT OVER THE HIER TERRAIN OF THE W WHERE LLVL MSTR IS A BIT
GREATER AND HOLD DOWN MAX TEMP RECOVERY WITH LLVL N WIND OFF LK SUP.
WL TEND TOWARD THE LOWER END OF GUIDANCE FOR TEMPS OVER THE NCENTRAL
AND W. MORE SUNSHINE OVER THE SCENTRAL AND E WITH H85 TEMPS UP TO
8-9C SHOULD ALLOW A SHARP CONTRAST TO THIS COOLER WX. EXPECT MAX
TEMPS UP TO 70 PER MIXING TO H85 ON FCST SDNGS AWAY FM THE LK
BREEZES THAT WL FORM IN PRESENCE OF WEAK GRADIENT ASSOCIATED WITH
THE HI.
SUN NGT THRU TUE...EXPECT DRY WX TO PREVAIL WITH NEAR STNRY HI PRES
UNDER UPR RDG AXIS EXTENDING E-W ACRS THE UPR LKS. ALTHOUGH H85
TEMPS ARE FCST TO REMAIN NEAR 8C...EXPECT A SLOW WARMING TREND AS
THE LLVLS SLOWLY MODERATE WITH HI SOLAR ANGLE. BUT WEAK PRES
GRADIENT UNDER THE SFC HI WL ALLOW LK BREEZES TO DVLP AND KEEP LK
SHORE COMMUNITIES COOLER. SOME MODELS GENERATE LGT QPF DURING THE
AFTNS WITH THE DAYTIME HEATING/LK BREEZE BNDRYS/LINGERING LLVL
MSTR...BUT WL NOT INCLUDE POPS ATTM GIVEN LARGE SCALE ACYC FLOW.
SUSPECT THERE WL BE QUITE A BIT OF DIURNAL CU. ALTHOUGH LGT WINDS WL
ALLOW FOR EFFICIENT RADIATIONAL COOLING...FCST PWATS REMAIN FAIRLY
HI ESPECIALLY OVER THE NW HALF. THE SHARPEST DIURNAL TEMP FALLS AT
NGT SHOULD BE OVER THE SCENTRAL AND E CLOSER TO THE CORE OF DRIER
AIR. OPTED TO INCLUDE A MENTION OF PATCHY FOG OVER THE INTERIOR WITH
THE LGT WINDS/FAIRLY SUBSTANTIAL LLVL MSTR.
TUE NGT INTO THU...APRCH OF WEAK SHRTWV FM THE W THAT WEAKENS RDG
OVER THE UPR LKS AND APRCH OF COLD FNT DROPPING S THRU ONTARIO ON
THE SRN FLANK OF DEEPENING UPR TROF CENTERED OVER HUDSON BAY WL
ALLOW A RETURN OF SOME -SHRA. SUSPECT THE BEST CHC FOR THESE SHRA WL
BE DURING THE DAY ON WED...WHEN DIURNAL HEATING WL BE IN PHASE WITH
DYNAMICS AHEAD OF THE APRCHG SHRTWV.
LATER THU THRU FRI...EXPECT A COOLING/DRYING TREND WITH N-NE WIND ON
THE SRN FLANK OF HI PRES BLDG INTO/THRU ONTARIO AND FCST H85 TEMPS
NEAR 0C BY FRI UNDER SLOWLY DEEPENING UPR TROF ACRS THE E HALF OF
NAMERICA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 747 AM EDT SAT MAY 4 2013
LOW CLOUDS...ALTERNATE LANDING MINS...WILL BE IN PLACE AT ALL THREE
SITES TO START TO PERIOD. BUT AS DRIER AIR MOVES WEST ACROSS UPPER
MICHIGAN...WOULD EXPECT CONDITIONS TO IMPROVE AT KSAW FIRST...WHERE
SKIES WILL LIKELY SCATTER OR CLEAR OUT THIS AFTERNOON. FARTHER
WEST...CONFIDENCE ON SCATTERING OUT AT THE OTHER TWO SITES IS
LIMITED...BUT THERE IS A DECENT CHANCE OF DIURNAL MIXING TO PUSH
KCMX TO MVFR CONDITIONS AND POSSIBLY EVEN KIWD. ALSO...THE FOG AT
KIWD THIS MORNING SHOULD COME TO AN END FAIRLY QUICKLY THIS MORNING
DUE TO DIURNAL MIXING.
ONCE DAYTIME HEATING IS LOST...IT APPEARS THAT THE LOW CLOUDS AND
FOG WILL TRY TO SETTLE BACK INTO THE TAF SITES WITH THE LIGHT
NORTHERLY FLOW OFF LAKE SUPERIOR. HIT LOW CLOUDS/FOG THE HARDEST AT
KIWD DUE TO THE FOG THIS MORNING AND WITH THEM BEING UNDER THE
DEEPEST LOW LEVEL MOISTURE. MOISTURE IS A LITTLE LESS CERTAIN AT
KCMX/KSAW...BUT STILL THINK THE CEILINGS AND MAYBE VISIBILITIES WILL
REACH IFR DURING THE OVERNIGHT HOURS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 416 AM EDT SAT MAY 4 2013
EXPECT N WINDS UP TO 20 KTS EARLY THIS MORNING TO DIMINISH THRU
TODAY/TONIGHT WITH APPROACH OF HI PRES FROM NW ONTARIO. WINDS WILL
THEN REMAIN LIGHT THRU NEXT WED WITH HI PRES/WEAK PRES GRADIENT
DOMINATING THE UPPER GREAT LAKES.
&&
.HYDROLOGY...
ISSUED AT 416 AM EDT SAT MAY 4 2013
THE STURGEON RIVER AT ALSTON AND CHASSELL...THE MICHIGAMME RIVER
AROUND WITCH LAKE...AND THE PAINT RIVER NEAR CRYSTAL FALLS WILL
REMAIN CONCERNS INTO AT LEAST EARLY NEXT WEEK...AND IN THE CASE OF
THE MICHIGAMME RIVER PERHAPS WELL INTO THE COMING WEEK. BUT
OTHERWISE RIVER LEVELS CONTINUE TO COME DOWN DESPITE SOME RECENT
HEAVY PRECIP THAT IMPACTED MAINLY THE W HALF OF UPR MI. IN FACT...A
DECENT AMOUNT OF WATER EQUIVALENT HAS OCCURRED SINCE THU OVER THE
WESTERN CWA...VCNTY OF IRONWOOD TO ONTONAGON...WITH OVER 2 INCHES
OVER FAR WESTERN GOGEBIC COUNTY. WILL HAVE TO ASSESS WHAT AFFECT THE
PRECIP WILL HAVE WHEN COMBINED WITH FURTHER MELTING OF ANY SUSTAINED
SNOWPACK WHEN TEMPS WARM SUN INTO NEXT WEEK. SNOW WATER EQUIVALENT
OF 8.8 INCHES IN PAINESDALE IN HOUGHTON COUNTY ON THURSDAY WITH 24
INCHES OF SNOW DEPTH...SO THE OTTER RIVER STILL HAS PLENTY OF SNOW
IN THE HEADWATERS WHICH MAY CAUSE ADDITIONAL PROBELMS AT CLLM4 IN
THE COMING DAYS.
FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD WARNINGS AND
ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 8 AM EDT /7 AM CDT/ THIS MORNING
FOR MIZ002-009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KC
AVIATION...SRF
MARINE...KC
HYDROLOGY...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
416 AM EDT SAT MAY 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 416 AM EDT SAT MAY 4 2013
AFTER BEING IN AN UNSETTLED WEATHER PATTERN FOR THE LAST SEVERAL
DAYS...THE AREA WILL TREND TOWARDS A DRIER PERIOD. WITH THE CUTOFF
LOW IS WELL TO OUR SOUTH AND THE NORTHERN STREAM JET FOCUSING
WELL NORTH INTO CANADA...THE AREA IS UNDER INCREASING UPPER LEVEL
RIDGING FROM THE RIDGE THAT HAS BEEN OVER EASTERN NORTH AMERICA.
THIS RIDGING...ALONG WITH SURFACE HIGH PRESSURE BUILDING OVER THE
UPPER GREAT LAKES WILL LEAD TO A DRIER AND WARMING TREND FOR THIS
WEEKEND.
THE FINAL PUSH FOR CENTRAL UPPER MICHIGAN IS CURRENTLY MOVING NNW
THIS MORNING AS THE 925MB WARM AIR ADVECTION SLOWLY PUSHES WEST.
FARTHER TO THE EAST...DRY MID LEVEL AIR SHOWN ON RAP ANALYSIS HAS
LED TO CLEAR SKIES OVER FAR EASTERN UPPER MICHIGAN ALONG THE
STALLED WARM FRONT AND ONLY MID TO HIGH CLOUDS OVER LAKE MICHIGAN
AND SOUTH CENTRAL UPPER MICHIGAN. LIGHT RAIN AND FREEZING RAIN IS
OCCURRING OVER THE FAR WEST...ALTHOUGH OBS AND RADAR ARE INDICATING
IT TO BE FAIRLY PATCHY. THERE ARE SOME STRONGER SHOWERS IN
SOUTHWEST WISCONSIN AND NORTHEAST IOWA...ASSOCIATED WITH SHORTWAVE
ENERGY PUSHING NORTHWEST THROUGH SOUTHWEST WISCONSIN AND THIS COULD
END UP BRUSHING THE FAR WESTERN CWA DURING THE AFTERNOON.
OTHERWISE...THE LIGHT PRECIPITATION OVER THE WEST WILL SLOWLY PUSH
OVER WESTERN LAKE SUPERIOR THROUGH THE DAY AND FALL AS RAIN WITH
THE 900-875MB TEMPS AROUND 8-9C. WITH LIGHT RAIN STILL OVER THE FAR
WEST AND TEMPERATURES BELOW FREEZING...WILL KEEP THE WINTER WEATHER
ADVISORY GOING UNTIL 12Z. ALL OF THE MODELS HAVE TEMPERATURES SLOWLY
RISING TO FREEZING OVER THE FAR WEST AT THAT TIME AND THEN SLOWLY
RISING ABOVE THAT AFTER SUNRISE. OTHERWISE...WITH THE LOW
LEVEL...SUB 900MB...NORTHEAST FLOW OVER THE WEST WILL KEEP THE LOW
CLOUDS IN PLACE THROUGH THE DAY.
THE DRIER AIR ALOFT SHOULD LEAD TO A DRY DAY ACROSS THE REST OF THE
CWA AND THE MAIN INFLUENCE ON THE WEATHER WILL BE THE LOCATION AND
DISSIPATION OF THE LOW CLOUDS OVER CENTRAL UPPER MICHIGAN. LATEST
TRENDS IN THE MODELS SHOW THAT THE LOW CLOUDS SHOULD DIMINISH
AROUND NOON OVER THE NORTH CENTRAL CWA. WITH THE EXPECTED LIGHT
NORTHERLY FLOW IN THE LOW LEVELS...NOT COMPLETELY CONFIDENT ON THAT
TIMING...SO ONLY WENT WITH PARTLY CLOUDY SKIES TOWARDS AFTERNOON.
BUT THE DRIER LOW LEVEL AIR TO THE SOUTHEAST...WONDERING IF THE
MODELS HAVE A HANDLE ON THE CLEARING IDEA AND THE FORECAST IS TOO
PESSIMISTIC. OTHERWISE...WOULD EXPECT MID-HIGH CLOUDS STREAMING
NORTHEAST ACROSS THE CENTRAL/EASTERN CWA THROUGH MUCH OF THE DAY.
AS FOR TEMPERATURES...EXPECT VALUES TO STRUGGLE TO REACH 40 OVER
THE FAR WEST UNDER THE CLOUDS. WITH THE BREAKS IN THE CLOUDS
OVER THE SOUTH CENTRAL AND EAST AND THE EXPECTED WESTWARD PUSH OF
THE 925/850MB TROUGH EARLY THIS MORNING AND THROUGH THE DAY ALLOWING
SOUTH-SOUTHEASTERLY FLOW TO DEVELOP OVER THE AREA...WOULD EXPECT
TEMPERATURES UNDER THE MAY SUN TO QUICKLY WARM INTO THE 50S/60S AND
A FEW LOWER 70S TOWARDS NEWBERRY. AS AN EXAMPLE...YESTERDAY WHERE
THE BREAKS IN THE CLOUDS WERE OVER THE EASTERN CWA...TEMPERATURES
WERE IN THE 50S AND LOWER 60S /DELTA...SCHOOLCRAFT...LUCE
COUNTIES/...BUT JUST TO THE WEST IN MARQUETTE COUNTY TEMPERATURES
WERE INN THE 30S. THUS...PINNING DOWN THE LOCATION/DISSIPATION OF
THE LOW CLOUDS CREATES A HUGE BUST POTENTIAL FOR HIGHS OVER THE
NORTH CENTRAL. NEAR LAKE SUPERIOR IN MARQUETTE COUNTY...THE NEAR
SURFACE FLOW WILL BE LIGHT AND NORTHERLY...WHICH WILL TRY TO KEEP
THE TEMPERATURES LOWER DUE TO LAKE SUPERIOR.
TONIGHT...HIGH PRESSURE CONTINUES TO BUILD OVER THE AREA...WHILE THE
925/850MB TROUGH DISSIPATES OVER EASTERN MINNESOTA AND FAR WESTERN
LAKE SUPERIOR. THIS SHOULD LEAD TO A DRY NIGHT ACROSS MUCH OF THE
AREA AND LIKE TODAY...THE CLOUDS WILL BE ONE OF THE MAIN FORECAST
CONCERNS. MODELS SHOWING THE LOW CLOUDS REMAINING OVER THE FAR WEST
WITH THE LINGERING NORTHEASTERLY FLOW THROUGH THE NIGHT. EXPECT THAT
TO BE THE CASE AND WILL KEEP CLOUDY SKIES THERE. IN
ADDITION...THERE MAY BE SOME LIGHT DRIZZLE/RAIN OVER THE FAR WEST
WITH THE LOW CLOUDS IN THE EVENING...BUT OVERALL MUCH OF THE
PRECIPITATION SHOULD HAVE DIMINISHED WITH THE WEAKENING FORCING OVER
THE WESTERN LAKE. THE SLIGHTLY UPSLOPE NORTHEAST FLOW OVER THE
WEST...HAVE ADDED A MENTION OF PATCHY FOG DUE TO THE LOW
CLOUDS INTERACTING WITH THE HIGHER TERRAIN.
OVER THE NORTH CENTRAL...MODELS ARE SHOWING THE LOWER CLOUDS
REDEVELOPING TONIGHT WITH THE LIGHT NORTHERLY FLOW AND LINGERING LOW
LEVEL MOISTURE. WILL GO WITH A PARTLY-MOSTLY CLOUDY SKY AND THEN
DIMINISH IT HEADING SOUTH TOWARDS IRON MOUNTAIN. ALSO ADDED A
MENTION OF FOG TO THE HIGHER TERRAIN LOCATIONS.
FARTHER EAST AND AWAY FROM LAKE SUPERIOR...EXPECT MOSTLY CLEAR
SKIES WITH A SLIM POTENTIAL FOR FOG DUE TO THE EXPECTED MIXING OUT
TODAY AND DRIER AIR IN PLACE. THE FOG POTENTIAL WILL LIKELY DEPEND
ON IF FOG DEVELOPS OVER EASTERN LAKE SUPERIOR TODAY. IF IT
DOES...THE LIGHT NORTHERLY WINDS WILL DRAG IT SOUTH INTO THE
EASTERN CWA. DON/T HAVE THE CONFIDENCE TO ADD AT THIS POINT AND IT
WILL BE SOMETHING FOR THE DAY SHIFT TO WATCH.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 416 AM EDT SAT MAY 4 2013
SUN...SFC HI PRES SINKING SLOWLY S FM ONTARIO WL SHIFT OVER LK SUP
BY LATE IN THE DAY UNDER UPR RDG AXIS TO THE N OF CLOSED LO SHIFTING
INTO THE SE CONUS. WITH THE ARRIVAL OF MORE ACYC FLOW/FRONTOLYSIS OF
LINGERING STNRY FNT AS WELL AS DIRUNAL HEATING...EXPECT MRNG LO CLDS
OVER THE NCENTRAL AND W TO SLOWLY DSPT. THESE CLDS WL BE MOST
PERSISTENT OVER THE HIER TERRAIN OF THE W WHERE LLVL MSTR IS A BIT
GREATER AND HOLD DOWN MAX TEMP RECOVERY WITH LLVL N WIND OFF LK SUP.
WL TEND TOWARD THE LOWER END OF GUIDANCE FOR TEMPS OVER THE NCENTRAL
AND W. MORE SUNSHINE OVER THE SCENTRAL AND E WITH H85 TEMPS UP TO
8-9C SHOULD ALLOW A SHARP CONTRAST TO THIS COOLER WX. EXPECT MAX
TEMPS UP TO 70 PER MIXING TO H85 ON FCST SDNGS AWAY FM THE LK
BREEZES THAT WL FORM IN PRESENCE OF WEAK GRADIENT ASSOCIATED WITH
THE HI.
SUN NGT THRU TUE...EXPECT DRY WX TO PREVAIL WITH NEAR STNRY HI PRES
UNDER UPR RDG AXIS EXTENDING E-W ACRS THE UPR LKS. ALTHOUGH H85
TEMPS ARE FCST TO REMAIN NEAR 8C...EXPECT A SLOW WARMING TREND AS
THE LLVLS SLOWLY MODERATE WITH HI SOLAR ANGLE. BUT WEAK PRES
GRADIENT UNDER THE SFC HI WL ALLOW LK BREEZES TO DVLP AND KEEP LK
SHORE COMMUNITIES COOLER. SOME MODELS GENERATE LGT QPF DURING THE
AFTNS WITH THE DAYTIME HEATING/LK BREEZE BNDRYS/LINGERING LLVL
MSTR...BUT WL NOT INCLUDE POPS ATTM GIVEN LARGE SCALE ACYC FLOW.
SUSPECT THERE WL BE QUITE A BIT OF DIURNAL CU. ALTHOUGH LGT WINDS WL
ALLOW FOR EFFICIENT RADIATIONAL COOLING...FCST PWATS REMAIN FAIRLY
HI ESPECIALLY OVER THE NW HALF. THE SHARPEST DIURNAL TEMP FALLS AT
NGT SHOULD BE OVER THE SCENTRAL AND E CLOSER TO THE CORE OF DRIER
AIR. OPTED TO INCLUDE A MENTION OF PATCHY FOG OVER THE INTERIOR WITH
THE LGT WINDS/FAIRLY SUBSTANTIAL LLVL MSTR.
TUE NGT INTO THU...APRCH OF WEAK SHRTWV FM THE W THAT WEAKENS RDG
OVER THE UPR LKS AND APRCH OF COLD FNT DROPPING S THRU ONTARIO ON
THE SRN FLANK OF DEEPENING UPR TROF CENTERED OVER HUDSON BAY WL
ALLOW A RETURN OF SOME -SHRA. SUSPECT THE BEST CHC FOR THESE SHRA WL
BE DURING THE DAY ON WED...WHEN DIURNAL HEATING WL BE IN PHASE WITH
DYNAMICS AHEAD OF THE APRCHG SHRTWV.
LATER THU THRU FRI...EXPECT A COOLING/DRYING TREND WITH N-NE WIND ON
THE SRN FLANK OF HI PRES BLDG INTO/THRU ONTARIO AND FCST H85 TEMPS
NEAR 0C BY FRI UNDER SLOWLY DEEPENING UPR TROF ACRS THE E HALF OF
NAMERICA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 129 AM EDT SAT MAY 4 2013
ABUNDANT LOW-LEVEL MOISTURE WILL LIKELY LINGER THRU MUCH OF THIS
FCST PERIOD...ESPECIALLY OVER WRN UPPER MI. AS A RESULT...KIWD WILL
LIKELY REMAIN UNDER IFR CONDITIONS THRU THIS EVENING...THOUGH IT`S
POSSIBLE CIGS MAY RISE TO LOW MVFR THIS AFTN. EXPECT OCNL
-FZDZ/-FZRA AT KIWD OVERNIGHT TO CHANGE TO -SHRA THIS MORNING AS
TEMPS SLOWLY RISE. PCPN SHOULD THEN END BY AFTN. AT KCMX...IFR
CONDITIONS WILL LIKELY PREVAIL THRU THE MORNING. SHOULD SEE SOME
IMPROVEMENT TO LOW MVFR THIS AFTN...AND IT`S POSSIBLE LOW CLOUDS
COULD SCATTER OUT AS DRIER AIR TRIES TO WORK WESTWARD. LOW
CONFIDENCE AT THIS POINT...SO LEFT MVFR CIGS IN PLACE INTO THE
EVENING. EXPECT OCNL -FZDZ TO TRANSITION TO OCNL -DZ AT KCMX IN THE
NEXT FEW HRS AS TEMPS SLOWLY RISE. AT KSAW...UPSLOPE NORTHERLY WINDS
WILL PROBABLY WORK TO MAINTAIN LIFR CONDITIONS THRU THE NIGHT ALONG
WITH -DZ/-SHRA AT TIMES. DRIER AIR WILL LIKELY MAKE INROADS INTO THE
AREA THIS AFTN...AND THERE IS A STRONGER MODEL TREND SUGGESTING THAT
WILL OCCUR. THUS...OPTED TO TREND FCST OPTIMISTIC TO VFR AT KSAW
THIS AFTN WITH LOW CLOUDS SCATTERING OUT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 416 AM EDT SAT MAY 4 2013
EXPECT N WINDS UP TO 20 KTS EARLY THIS MORNING TO DIMINISH THRU
TODAY/TONIGHT WITH APPROACH OF HI PRES FROM NW ONTARIO. WINDS WILL
THEN REMAIN LIGHT THRU NEXT WED WITH HI PRES/WEAK PRES GRADIENT
DOMINATING THE UPPER GREAT LAKES.
&&
.HYDROLOGY...
ISSUED AT 416 AM EDT SAT MAY 4 2013
THE STURGEON RIVER AT ALSTON AND CHASSELL...THE MICHIGAMME RIVER
AROUND WITCH LAKE...AND THE PAINT RIVER NEAR CRYSTAL FALLS WILL
REMAIN CONCERNS INTO AT LEAST EARLY NEXT WEEK...AND IN THE CASE OF
THE MICHIGAMME RIVER PERHAPS WELL INTO THE COMING WEEK. BUT
OTHERWISE RIVER LEVELS CONTINUE TO COME DOWN DESPITE SOME RECENT
HEAVY PRECIP THAT IMPACTED MAINLY THE W HALF OF UPR MI. IN FACT...A
DECENT AMOUNT OF WATER EQUIVALENT HAS OCCURRED SINCE THU OVER THE
WESTERN CWA...VCNTY OF IRONWOOD TO ONTONAGON...WITH OVER 2 INCHES
OVER FAR WESTERN GOGEBIC COUNTY. WILL HAVE TO ASSESS WHAT AFFECT THE
PRECIP WILL HAVE WHEN COMBINED WITH FURTHER MELTING OF ANY SUSTAINED
SNOWPACK WHEN TEMPS WARM SUN INTO NEXT WEEK. SNOW WATER EQUIVALENT
OF 8.8 INCHES IN PAINESDALE IN HOUGHTON COUNTY ON THURSDAY WITH 24
INCHES OF SNOW DEPTH...SO THE OTTER RIVER STILL HAS PLENTY OF SNOW
IN THE HEADWATERS WHICH MAY CAUSE ADDITIONAL PROBELMS AT CLLM4 IN
THE COMING DAYS.
FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD WARNINGS AND
ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 8 AM EDT /7 AM CDT/ THIS MORNING
FOR MIZ002-009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KC
AVIATION...ROLFSON
MARINE...KC
HYDROLOGY...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
131 AM EDT SAT MAY 4 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 418 PM EDT FRI MAY 3 2013
UPPER TROUGH CONTINUES TO SPLIT APART NEXT 24 HRS WITH UPPER LOW
FOCUSING OVER CNTRL MISSISSIPPI RIVER VALLEY. REGIONAL RADAR SHOWS
SWATH OF MAINLY RAIN FROM ILLINOIS INTO WISCONISN AND INTO WESTERN
UPR MICHIGAN AND INTO MINNESOTA ARROWHEAD. THIS PRECIP IS SUPPORTED
BY PERSISTENT H85-H7 FRONTOGENESIS AND RIGHT ENTRANCE REGION FROM
UPPER JET OVER ONTARIO. BOTH FEATURES ARE FORECAST TO DIMINISH INTO
SATURDAY AS UPPER LOW TO THE SOUTH BECOMES DOMINANT UPPER LEVEL
FEATURE.
ANALYSIS FROM RUC AND NAM INDICATING WARM LAYER IS WELL ABOVE 0C
SUGGESTS PTYPE OVER WESTERN UPR MICHIGAN SHOULD BE RAIN BUT REPORTS
FROM GOGEBIC INTO SOUTHERN HOUGHTON COUNTY SHOW IT IS NOT WITH LGT
SNOW OCCURRING. THESE AREAS LINE UP WELL WITH SUB ZERO 950-900MB
TEMPS SO KEPT MENTION OF SLEET/SNOW OVER FAR WESTERN UPR MICHIGAN
THROUGH EARLY MORNING HOURS BEFORE SHALLOWER COLD TEMPS WARM ABOVE
0C. OTHERWISE...RAIN WILL BE DOMINANT PTYPE ACROSS REST OF
CWA...MORE SCATTERED IN THE EASTERN HALF OF CWA. KEPT A MENTION OF
FZRA OVER INLAND WESTERN THIRD OF CWA. SINCE MAJORITY OF PRECIP WILL
OCCUR OVER WESTERN CWA AND SINCE THERE IS GOING TO BE CONTINUING
FZRA/SLEET/SNOW...CHANGING TO RAIN/FREEZING RAIN...OPTED TO KEEP
WINTER WEATHER ADVY OUT FOR GOGEBIC AND ONTONAGON COUNTIES THROUGH
12Z SATURDAY. COULD SEE SIMILAR PYTPE THIS EVENING FARTHER EAST
ACROSS KEWEENAW...BUT BASED ON UPSTREAM RADAR TRENDS AND BLEND OF
SHORT TERM MODELS...THINK THESE AREAS WILL MISS OUT ON HEAVIER QPF
AND BETTER CHANCE OF SLEET/ICE ACCUMS.
IMPROVING WEATHER ON SATURDAY...HOPEFULLY. LINGERING DIVERGENCE
ALOFT MAY STILL BRING SOME LGT RAIN OVER WEST AND NORTHWEST CWA.
SHOULD STAY DRY OVER THE EAST HALF. SIMILAR TO LAST COUPLE DAYS
SHOULD BE A WIDE TEMPERATURE RANGE FROM WEST TO EAST. BASED ON FCST
H85 TEMPS AND CLEARER SKIES EXPECTED...THINKING EASTERN INTERIOR
CWA MAY REACH MID 60S TO LOWER 70S. COOLER NORTH FLOW KEEPS WEST AND
CNTRL COOLER...BUT STILL A BIT WARMER THAN RECENT TEMPERATURES.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 418 PM EDT FRI MAY 3 2013
NAM SHOWS A CLOSED 500 MB LOW OVER NORTHERN CA AND ANOTHER OVER
NORTHERN ARKANSAS WITH A 500 MB RIDGE OVER THE LOWER GREAT LAKES.
THE 500 MB PATTERN OVER THE EAST HALF OF THE U.S. IS AN OMEGA BLOCK
00Z SUN AND DOES NOT MOVE MUCH ON SUNDAY EXCEPT TO TRY TO FORM A REX
BLOCK WITH THE LOW MOVING SLOWLY EAST UNDERNEATH THE RIDGE. THE REX
BLOCK THEN GETS ESTABLISHED ON MON. THIS FORECAST PERIOD FEATURES
DEEPER MOISTURE OVER THE WEST HALF OF THE CWA GRADUALLY DECREASING.
WILL KEEP SLIGHT CHANCE POPS OVER THE FAR WESTERN CWA SAT NIGHT WITH
THIS MOVING FURTHER WEST WITH TIME ON SUN. PCPN SHOULD BE ALL RAIN
BY THAT TIME. TEMPERATURES CONTINUE THE SLOW WARMING TREND WITH TIME
AND DRY WEATHER COMES IN FOR SUN INTO MON. DID NOT MAKE TOO MANY
CHANGES TO THE GOING FORECAST FOR TEMPERATURES EXCEPT DID LOWER LOWS
A BIT WITH THE COLDER MOS GUIDANCE FOR SAT NIGHT AND SUN NIGHT.
IN THE EXTENDED...ECMWF AND GFS SHOW A CLOSED 500 MB LOW OVER THE
SOUTHEAST U.S. 12Z TUE. THINGS GET INTERESTING OVER THE NORTHERN
PLAINS. 12Z TUE...ECMWF HAS A CLOSED 500 MB LOW NEAR SISSETON SD AND
THE GFS HAS A 500 MB RIDGE THERE INSTEAD. THIS DIFFERENCE CARRIES
INTO 12Z WED WITH THE ECMWF CONTINUING ITS SOLUTION OF A TROUGH IN
THE UPPER MISSISSIPPI VALLEY WITH THE 06Z GFS HAVING A CLOSED 500 MB
LOW OVER MISSOURI WHILE THE 00Z GFS STILL MAINTAINING A RIDGE OVER
THE CORNBELT. THE ECMWF TAKES THE TROUGH INTO THE UPPER GREAT LAKES
12Z THU WITH THE GFS MAINTAINING A FLAT 500 MB RIDGE OVER THE AREA.
THE 500 MB RIDGE GETS FLATTENED BY 12Z FRI WITH A BROAD 500 MB
TROUGH AND THE WESTERLIES GETTING PUSHED SOUTH INTO THE AREA.
CONFIDENCE REMAINS LOW WITH THIS EXTENDED FORECAST DUE TO THE 2 VERY
DIFFERENT MODEL SOLUTIONS. LOOKS DRY THROUGH TUE NIGHT BEFORE A COLD
FRONT HEADS SOUTH OUT OF CANADA AND BRINGS WITH IT A SLIGHT CHANCE
TO LOW CHANCE FOR PCPN WED INTO FRI. TEMPERATURES CONTINUE TO SLOWLY
WARM AND GO TO NEAR NORMAL BY THE END OF THE PERIOD. THE COLD FRONT
MOVES THROUGH WED NIGHT AND SLOWLY PUSHES SOUTH OF THE AREA THEN FOR
THU INTO FRI.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 129 AM EDT SAT MAY 4 2013
ABUNDANT LOW-LEVEL MOISTURE WILL LIKELY LINGER THRU MUCH OF THIS
FCST PERIOD...ESPECIALLY OVER WRN UPPER MI. AS A RESULT...KIWD WILL
LIKELY REMAIN UNDER IFR CONDITIONS THRU THIS EVENING...THOUGH IT`S
POSSIBLE CIGS MAY RISE TO LOW MVFR THIS AFTN. EXPECT OCNL
-FZDZ/-FZRA AT KIWD OVERNIGHT TO CHANGE TO -SHRA THIS MORNING AS
TEMPS SLOWLY RISE. PCPN SHOULD THEN END BY AFTN. AT KCMX...IFR
CONDITIONS WILL LIKELY PREVAIL THRU THE MORNING. SHOULD SEE SOME
IMPROVEMENT TO LOW MVFR THIS AFTN...AND IT`S POSSIBLE LOW CLOUDS
COULD SCATTER OUT AS DRIER AIR TRIES TO WORK WESTWARD. LOW
CONFIDENCE AT THIS POINT...SO LEFT MVFR CIGS IN PLACE INTO THE
EVENING. EXPECT OCNL -FZDZ TO TRANSITION TO OCNL -DZ AT KCMX IN THE
NEXT FEW HRS AS TEMPS SLOWLY RISE. AT KSAW...UPSLOPE NORTHERLY WINDS
WILL PROBABLY WORK TO MAINTAIN LIFR CONDITIONS THRU THE NIGHT ALONG
WITH -DZ/-SHRA AT TIMES. DRIER AIR WILL LIKELY MAKE INROADS INTO THE
AREA THIS AFTN...AND THERE IS A STRONGER MODEL TREND SUGGESTING THAT
WILL OCCUR. THUS...OPTED TO TREND FCST OPTIMISTIC TO VFR AT KSAW
THIS AFTN WITH LOW CLOUDS SCATTERING OUT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 418 PM EDT FRI MAY 3 2013
NO GALES SEEN DURING THIS FORECAST PERIOD. THE STRONGEST WINDS IN
THE PERIOD ARE THIS AFTERNOON WITH NORTHEAST WINDS BELOW 25 KNOTS. A
HIGH PRESSURE RIDGE SETTLES IN AND KEEPS STRONG SYSTEMS AWAY FROM
THE AREA.
&&
.HYDROLOGY...
ISSUED AT 418 PM EDT FRI MAY 3 2013
STURGEON RIVER AT ALSTON AND CHASSELL...THE MICHIGAMME RIVER AROUND
WITCH LAKE...AND THE PAINT RIVER NEAR CRYSTAL FALLS WILL REMAIN
CONCERNS INTO AT LEAST EARLY NEXT WEEK...BUT OTHERWISE RIVER LEVELS
CONTINUE TO COME DOWN. ACTUALLY...MICHIGAMME MAY REMAIN A CONCERN
THROUGH MOST OF NEXT WEEK. DECENT AMOUNT OF WATER EQUIVALENT HAS
OCCURRED LAST TWO DAYS OVER WESTERN CWA...VCNTY OF IRONWOOD TO
ONTONAGON...OVER 2 INCHES OVER FAR WESTERN GOGEBIC COUNTY. WILL HAVE
TO ASSESS WHAT AFFECT THE PRECIP WILL HAVE WHEN COMBINED WITH
FURTHER MELTING OF ANY SUSTAINED SNOWPACK WHEN TEMPS WARM INTO THE
60-70S SUN INTO NEXT WEEK. SNOW WATER EQUIVALENT OF 8.8 INCHES IN
PAINESDALE ON THURSDAY WITH 24 INCHES OF SNOW DEPTH...SO THE OTTER
RIVER STILL HAS PLENTY OF SNOW IN THE HEADWATERS WHICH MAY CAUSE
ADDITIONAL PROBELMS AT CLLM4 IN THE COMING DAYS.
FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD WARNINGS AND
ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 8 AM EDT /7 AM CDT/ THIS MORNING
FOR MIZ002-009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...07
AVIATION...ROLFSON
MARINE...07
HYDROLOGY...JLA
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
355 PM CDT SAT MAY 4 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 341 PM CDT SAT MAY 4 2013
WARMER WEATHER WILL GRADUALLY MOVE IN ACROSS THE REGION OVER THE
NEXT FEW DAYS AND CONDITIONS BEGIN TO DRY OUT. BY THE MIDDLE OF THE
WEEK A SERIES OF UPPER LEVEL DISTURBANCES WILL BRING RETURNED
CHANCES FOR SHOWERS AND THUNDERSTORMS...ALONG WITH COOLER
TEMPERATURES.
EARLY AFTERNOON NORTH AMERICAN WATER VAPOR IMAGERY TOGETHER WITH
500MB HEIGHTS AND WINDS SHOWED THE CUTOFF LOW SPINNING OVER THE
OZARK MOUNTAINS...WITH A RIDGE LOCATED ALONG EACH COAST. AT THE
SURFACE A LOOSE PRESSURE GRADIENT WAS DRAPED ACROSS THE UPPER
MIDWEST BETWEEN A 1028 HIGH IN NORTH DAKOTA...AND A 1013 LOW IN
SOUTHERN MISSOURI WITH NORTHERLY WINDS OVER MINNESOTA AND
WISCONSIN. THE EXPANSIVE CLOUD SHIELD FROM THE AFOREMENTIONED
UPPER LEVEL LOW WAS BEGINNING TO SHOW SOME HOLES IN
WISCONSIN...AND THIS ALLOWED TEMPERATURES TO CLIMB INTO THE MID
70S WHERE THERE WAS NO SNOWPACK. HOWEVER...FARTHER WEST
TEMPERATURES WERE ONLY IN THE 40S WHERE THE DEEP SNOWPACK LINGERED
FROM THE PREVIOUS WINTER STORM. FARTHER WEST STILL IN NEAR THE
SD/MN BORDER TEMPERATURES WERE ONLY IN THE UPPER 30S ALONG WITH
THICKER CLOUDS AND LIGHT DRIZZLE ASSOCIATED WITH THE DEFORMATION
ZONE FROM THE DECAYING CYCLONE TO THE SOUTH. TONIGHT FORECAST
MODELS SHOW THE PRESSURE GRADIENT RELAXING...RESULTING IN
DECREASING WINDS. AS THE CLEARING TREND PROGRESSES WESTWARD
OVERNIGHT AREAS OF FOG ARE EXPECTED TO DEVELOP ALONG THE MN/WI
BORDER...WITH THE HIGHEST POTENTIAL FOR DENSE FOG ALONG AND EAST
OF A LINE FROM ALBERT LEA UP THROUGH RED WING AND RICE LAKE WI.
FORECAST SOUNDINGS SHOW A DEEP INVERSION WITH LOW LEVEL
MOISTURE...BUT FEEL THE WINDS ARE OVERDONE...SO THE FOG POTENTIAL
IS HIGHER THAN INDICATED. MEMBER 2 OF THE HOPWRF HAS A BETTER
HANDLE OF THE CLEARING TREND...AND SHOWS FOG DEVELOPMENT IN THIS
REGION AROUND 08Z. THE 16Z RUN OF THE HRRR SHOWS A SIMILAR TREND.
THEREFORE HAVE ISSUED A DENSE FOG ADVISORY OVERNIGHT. HIGH
TEMPERATURES ON SUNDAY WILL DEPEND ON HOW QUICKLY WE CAN MIX OUT
THE FOG. THIS WILL BE DIFFICULT TO DO WITH LIGHT WINDS AND WEAK
MECHANICAL MIXING...SO WILL HAVE TO DEPEND ON THE EARLY MAY SUN.
TEMPERATURES ACROSS THE WEST WILL BE 15 TO 20 DEGREES COOLER THAN
SNOW FREE AREAS OF WISCONSIN DUE TO CLOUD COVER.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 341 PM CDT SAT MAY 4 2013
SUNDAY NIGHT WILL HAVE ANOTHER FAVORABLE SETUP FOR FOG
DEVELOPMENT. ON MONDAY SURFACE TEMPERATURES WILL REBOUND TO NEAR
70 DEGREES...WITH WARMER TEMPS ON TUESDAY AS SOUTHERLY FLOW
INCREASES AHEAD OF THE NEXT WEAK UPPER LEVEL WAVE. USED A MIX DOWN
TOOL TO FORECAST HIGH TEMPERATURES...AND INCREASED THEM A FEW
DEGREES ABOVE THE PREVIOUS FORECAST...ESPECIALLY IN FAR WESTERN
MINNESOTA. THIS WAVE IS FORECAST TO BRING A CHANCE FOR SHOWERS AND
THUNDERSTORMS WEDNESDAY. THE SEVERE WEATHER THREAT IS VERY
LOW...WITH SMALL DEEP LAYER SHEAR AND ONLY 500J/KG OF MLCAPE.
UNSETTLED WEATHER WILL CONTINUE THROUGH THE END OF THE WEEK. LOW
POPS AND SLIGHTLY COOLER TEMPERATURES WILL BE FOCUSED ALONG A WARM
FRONT THAT IS FORECAST TO STALL OUT ACROSS THE REGION...AS
PERIODIC SHORTWAVES MOVING ACROSS THE UPPER MIDWEST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT
1230 PM CDT SAT MAY 4 2013
HIGH PRESSURE OVER SOUTH CENTRAL CANADA IS STUCK IN PLACE AS AN
UPPER LEVEL LOW OVER SOUTHWEST MISSOURI SLOWLY DRIFTS TO CENTRAL
ALABAMA BY SUNDAY NIGHT. AS THE LOW DRIFTS SOUTHEAST CHANCES FOR
ANY PRECIPITATION WILL CONTINUE TO DECREASE. BY SUNDAY AFTERNOON
IFR CONDITIONS WILL TREND TO MVFR/VFR. THERE MAYBE A SPRINKLE OR
TWO AND SOME LIGHT DRIZZLE THIS AFTERNOON BUT NOT ENOUGH TO
MENTION IN THE TERMINALS. BETTER CHANCES FOR THE SPRINKLES
NORTH AND NORTHWEST OF KMSP. FOR KRNH/KEAU SATELLITE INDICATES
CLEARING OVER WESTERN WI. THAT MAY BE SHORT LIVED DUE TO THE VERY
WET GROUND AND COOL TEMPERATURES LEADING TO A SCT-BKN
DECK...REMAINING VFR CONDITIONS THOUGH. AT ANY RATE PLENTY OF LOW
LEVEL MOISTURE IN PLACE FOR FOG FORMATION RIGHT AFTER SUNSET
TONIGHT. SHOULD SEE A PERIOD OR TWO OF DRIZZLE AFTER MIDNIGHT.
EXPECT LIFR CIGS TO BE MORE PROMINENT OVER THE WI TERMINALS. MAY
SEE LIFR VISIBILITIES OVER THE WI TERMINALS TOO BUT NOT THAT
CONFIDENT TO ADD THEN AT THIS POINT IN TIME.
KMSP...
THE PRIMARY CONCERN IS THE THREAT OF DRIZZLE LATER TONIGHT AND
CLOSE TO LIFR CIGS. NO REASON TO SEE CURRENT CIGS INCREASE UNTIL
AFTER 13Z SUNDAY. MAY BE A PERIOD OR TWO OF LIFR AFTER 07Z. DO NOT
EXPECT IT TO PERSIST. NORTH- NORTHEAST WINDS /010-030/ WILL
PREVAIL THIS AFTERNOON AT SPEEDS OF 8 TO 12 KTS...THEN DECREASE TO AROUND
5-6KTS AFTER SUNSET AND REMAIN THAT WAY ALL DAY SUNDAY. CEILINGS
SHOULD RISE TO VFR BY 19Z AND MAYBE SCATTER OUT.
/OUTLOOK FOR KMSP/
MON...VFR. WINDS LIGHT/VARIABLE.
TUE...VFR. WINDS LIGHT/VARIABLE.
WED...VFR. WIND SOUTH AT 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...DENSE FOG ADVISORY FROM 1 AM TO 10 AM CDT SUNDAY FOR MNZ078-085-
093.
WI...DENSE FOG ADVISORY FROM 1 AM TO 10 AM CDT SUNDAY FOR WIZ015-016-
023>028.
&&
$$
SHORT TERM...JRB
LONG TERM...JRB
AVIATION...DRL
AREA FORECAST DISCUSSION
NWS HASTINGS NE
700 PM CDT SUN MAY 5 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 345 PM CDT SUN MAY 5 2013
OTHER THAN THE FAIRLY LOW PROBABILITY OF SOME PATCHY FOG
OVERNIGHT...THE NEXT 24 HOURS ARE LOOKING DRY AND RATHER
UNEVENTFUL...AS TEMPERATURES FINALLY MAKE A LEGITIMATE RUN BACK
TOWARD 70 DEGREES ON MONDAY.
19Z OBJECTIVE SURFACE ANALYSIS HIGHLIGHTS A BROAD...ROUGHLY 1022
MILLIBAR NORTH-SOUTH ORIENTED RIDGE AXIS EXTENDING SOUTHWARD
ACROSS THE CENTRAL CONUS...IN THE WAKE OF THE DEPARTED SURFACE LOW
REFLECTION OF THE SLOW-MOVING CUT OFF UPPER LOW. BREEZES THIS
AFTERNOON ACROSS THE CWA ARE GENERALLY OUT OF THE NORTH AT
SUSTAINED SPEEDS 10-15 MPH WITH SOME HIGHER GUSTS. ALOFT...WATER
VAPOR IMAGERY AND SHORT TERM MODEL DATA HIGHLIGHT A SPLIT-FLOW
UPPER AIR PATTERN THAT WILL DEFINE MUCH OF THE WEEK...WITH THE
CENTRAL PLAINS LOCATED NORTH OF THE SOUTHERN STREAM AND SOUTH OF
THE NORTHERN STREAM. DIRECTLY OVERHEAD IN THE MID LEVELS...FAIRLY
WEAK WEST-NORTHWEST FLOW PREVAILS...AS THE CENTRAL PLAINS LIES IN
BETWEEN TWO DOMINANT CLOSED 500 MILLIBAR LOWS..ONE DEPARTING
ACROSS THE SOUTHEAST STATES...AND ANOTHER CENTERED JUST OFF THE
CA COAST. IN BETWEEN...A MID/UPPER RIDGE EXTENDS NORTH TOWARD THE
CENTRAL PLAINS FROM MEXICO...BUT WITH ANOTHER SMALL-SCALE CUT
CLOSED MID LEVEL LOW SPINNING JUST TO THE NORTH OVER SD. AS
OUTLINED IN THE EARLIER DISCUSSION...SKY COVER AND RESULTANT TEMPS
WERE AT THE MERCY OF LOW STRATUS SCATTERING OUT AND/OR CLEARING
FROM WEST-EAST...AND ALL THINGS CONSIDERED...THINGS HAVE ACTUALLY
WORKED OUT FAIRLY WELL WITH ROUGHLY THE WESTERN 2/3 OF THE CWA NOW
PREDOMINANTLY SUNNY-PARTLY CLOUDY AT THIS HOUR...WHILE MOSTLY
CLOUDY SKIES ARE HANGING ON LONGER MAINLY EAST OF HIGHWAY 14.
HIGH TEMPS APPEAR ON TRACK TO RANGE FROM THE UPPER 50S NORTHEAST
TO MID 60S SOUTHWEST. FORTUNATELY FOR FIRE WEATHER CONCERNS...WINDS
ARE GUSTING WELL UNDER 25 MPH...AS DEWPOINTS HAVE CRASHED ENOUGH
TO DROP RELATIVE HUMIDITY VALUES TO NEAR/SLIGHTLY BELOW 20 PERCENT
IN THE EXTREME WESTERN CWA...MAINLY WESTERN DAWSON/GOSPER/FURNAS
COUNTIES.
HEADING INTO THIS EVENING/TONIGHT...WILL RUN WITH THE ASSUMPTION
THAT THE CURRENTLY ERODING STRATUS DECK WILL CONTINUE TO FADE AWAY
EASTWARD WITH TIME INTO THE OAX/TOP AREAS...AND NOT COMPLETELY
STALL OUT IN OUR EASTERN COUNTIES OR EVEN PUSH BACK WEST.
HOWEVER...AM NOT 100 PERCENT CONFIDENT IN THIS...GIVEN THAT
STEERING FLOW AT 900MB DOES TURN MORE EASTERLY TONIGHT...SO WILL
HAVE TO KEEP AN EYE ON THESE LOW LEVEL CLOUD TRENDS. OTHERWISE...A
GRADUAL INCREASE IN MAINLY THIN MID/HIGH CLOUDS WILL OCCUR
TONIGHT...IN RESPONSE TO SUBTLE...LOW AMPLITUDE ENERGY LIFTING
NORTHEAST TOWARD THE CENTRAL PLAINS OUT AHEAD OF THE AFOREMENTIONED
WESTERN CONUS PARENT TROUGH/CLOSED LOW. GIVEN THAT SKIES SHOULD
GENERALLY AVERAGE PARTLY CLOUDY OVERNIGHT...ESPECIALLY WEST...AM
NOT ANTICIPATING IDEAL RADIATIONAL COOLING CONDITIONS DESPITE THE
CONTINUED PRESENCE OF THE LOW LEVEL RIDGE AXIS SITTING DIRECTLY
OVER THE AREA...WHICH WILL RESULT IN SEVERAL HOURS OF GENERALLY
LIGHT/VARIABLE TO EASTERLY BREEZES. FOR LOW TEMPS...SLIGHTLY
UNDERCUT A BLEND OF 12Z MET/MAV GUIDANCE...WHICH RESULTS IN THE
MAJORITY OF THE AREA BOTTOMING OUT BETWEEN 38-43...AND MAYBE DOWN
AROUND 36 IN THE COLDER-PRONE WESTERN DAWSON COUNTY AREA. THAT
BEING SAID...IF SKIES AVERAGE CLEARER THAN ANTICIPATED...COULD SEE
MORE OF THE CWA MAKE A RUN TOWARD THE MID 30S...AND THIS WILL NEED
WATCHED IN CASE A FEW SPOTS FLIRT WITH FROST-WORTHY READINGS. FOR
NOW...HAVE LEFT OUT FROST MENTION ALL AREAS. HOWEVER...HAVE LEFT
IN A MENTION OF PATCHY FOG CWA-WIDE FROM 09Z-13Z AS THE LIGHT WIND
REGIME COULD PROMOTE SOME DEVELOPMENT. THIS WOULD GENERALLY SEEM
MOST FAVORED WITHIN THE EASTERN 1/2 OF THE CWA IN CLOSEST
PROXIMITY TO THE WEST EDGE OF LOWER STRATUS...AND ALSO OVER WHERE
A BIT MORE LIGHT PRECIP FELL DURING THE PAST FEW DAYS. FOR
NOW...AM NOT EXPECTING SIGNIFICANT VISIBILITY ISSUES...BUT ITS
WORTH NOTING THAT THE LATEST HRRR ACTUALLY DOES SUGGEST SOME
DENSER FOG DEVELOPMENT MAINLY EAST OF HIGHWAY 281...SO THIS ALSO
BEARS WATCHING.
TURNING TO THE DAYTIME HOURS MONDAY...THE OVERALL MID/UPPER AIR
PATTERN CHANGES LITTLE...AS THE CENTRAL PLAINS REMAIN UNDER FAIRLY
UNEVENTFUL QUASI-ZONAL FLOW ALOFT...AND STILL DOWNSTREAM FROM A
LEAD SHORTWAVE EJECTING NORTHEAST TOWARD THE REGION FROM THE
DESERT SOUTHWEST...WHICH COULD PROMOTE SOME RAIN CHANCES MONDAY
NIGHT AS DESCRIBED BELOW. IN ADDITION...JUST TO THE NORTH THE
COMPACT LITTLE CLOSED LOW OVER SD SHOULD PRETTY MUCH REMAIN IN
PLACE...WITH LITTLE CONSEQUENCE INTO NEB/KS. AT THE SURFACE...THE
RIDGE AXIS WILL ONLY SLOWLY EDGE EAST DURING THE DAY...PROVIDING A
DAY OF FAIRLY LIGHT BREEZES. EVEN DURING THE AFTERNOON...THE
EASTERN 1/2 OF THE CWA WILL ONLY AVERAGE AROUND 5 MPH...WHILE
WESTERN COUNTIES PICK UP A SLIGHTLY STRONGER EAST-SOUTHEAST BREEZE
OF 10 TO POSSIBLY 15 MPH. ASSUMING THAT SKIES AVERAGE MOSTLY
CLEAR/PARTLY CLOUDY UNDER ONLY PASSING MID-HIGH CLOUDS...SHOULD
SEE A NICE JUMP IN HIGH TEMPS VERSUS TODAY...AND MADE LITTLE
CHANGE TO PREVIOUS FORECAST WITH ALL AREAS RISING TO WITHIN A FEW
DEGREES EITHER SIDE OF 70. THE ONLY CAVEAT FOR THESE WARM TEMPS
WOULD BE IF ANY MORNING FOG TURNS INTO A SLOW-ERODING STRATUS
DECK THAT LINGERS WELL INTO THE DAY WITHIN THE RIDGE AXIS MAINLY
IN THE EASTERN CWA...BUT IT SEEMS UNLIKELY THAT THE SITUATION GETS
THIS PESSIMISTIC.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 345 PM CDT SUN MAY 5 2013
A PROLONGED PERIOD OF UNSETTLED WEATHER IS SHAPING UP
ACROSS THE REGION AS THE UPPER LEVEL LOW OFF THE CALIFORNIA COAST
SLOWLY PROGRESSES EASTWARD WHILE SPINNING OFF SEVERAL WEAK
DISTURBANCES AHEAD OF IT. WHILE A GENERALLY BLOCKY PATTERN WITH
RIDGING WILL EXIST ACROSS THE CENTRAL PLAINS THROUGH MUCH OF THE
PERIOD...THE LOW LEVEL FLOW WILL BEGIN TO SHIFT AND BECOME SOUTHERLY
LATE MONDAY...HELPING MOISTURE ADVECT NORTHWARD. THIS FLOW SHOULD
HELP DEWPOINTS CLIMB BACK INTO THE 50S BY TUESDAY AFTERNOON...WITH
BUILDING INSTABILITY ACROSS THE PLAINS.
WHILE INITIALLY...THERE WILL BE A SMALL CHANCE FOR SOME RAIN SHOWERS
AHEAD OF THE FIRST UPPER LEVEL WAVE SPINNING OFF THE WESTERN
LOW...INSTABILITY WILL BE VERY WEAK...AND LOW LEVEL MOISTURE WILL
STILL BE LACKING...IN ORDER TO SUPPORT MUCH IN THE WAY OF SHOWER OR
THUNDERSTORM ACTIVITY. AS A RESULT...SLOWED DOWN THE INITIAL TIMING
OF THE ONSET OF ANY PRECIPITATION TO THE PRE-DAWN HOURS TUESDAY. AS
MOISTURE CONTINUES TO SURGE NORTH DURING THE DAY TUESDAY
AFTERNOON...INSTABILITY WILL BUILD...AND SEE THE POTENTIAL FOR SOME
THUNDERSTORMS TO DEVELOP DURING THE LATE MORNING/EARLY AFTERNOON
HOURS AS STEEP LOW LEVEL LAPSE RATES WILL REQUIRE LITTLE IN THE WAY
OF FORCING FOR SHOWER AND THUNDERSTORM DEVELOPMENT. AS WE THEN
TRANSITION INTO TUESDAY NIGHT...THE NOSE OF THE LOW LEVEL JET IS
EXPECTED TO BE POINTED TOWARDS THE LOCAL AREA...WHICH SHOULD ALLOW
FOR THE DEVELOPMENT OF ELEVATED CONVECTION ACROSS THE LOCAL AREA
DURING THE LATE EVENING AND OVERNIGHT HOURS...SOME OF WHICH COULD
BECOME STRONG TO MARGINALLY SEVERE. AS A RESULT...PLAN ON
HIGHLIGHTING THE POTENTIAL FOR SOME MARGINALLY SEVERE HAIL FOR THE
TUESDAY NIGHT PERIOD IN THE AFTERNOON HWO.
BEYOND TUESDAY NIGHT...THINGS GET A LITTLE MORE MUDDLED AS MULTIPLE
WEAK DISTURBANCES AHEAD OF THE MAIN UPPER LEVEL LOW TRANSITION
ACROSS THE PLAINS. EVEN SO...THERE IS SOME AGREEMENT AMONGST THE
MODELS FOR ANOTHER DECENT SHOT OF PRECIPITATION ACROSS NORTH
CENTRAL KANSAS AND PORTIONS OF SOUTH CENTRAL NEBRASKA WEDNESDAY
NIGHT AND THURSDAY...AND SAW NO REASON TO REDUCE THE LIKELY POPS
GIVEN BY THE ALLBLEND SOLUTION FOR THIS PERIOD. THEN...DEPENDING ON
WHICH MODEL SOLUTION YOU BELIEVE...THE MAIN UPPER LEVEL LOW SHOULD
BEGIN TO TRACK EASTWARD ON FRIDAY...WITH A COLD FRONT DROPPING DOWN
ACROSS THE NORTHERN PLAINS FRIDAY NIGHT OR SATURDAY. DUE TO THE
DISCREPANCIES IN TIMING...HUNG ONTO CHANCES FOR PRECIPITATION
THROUGH SATURDAY AFTERNOON...WITH PRECIPITATION COMING TO AN END
BEHIND THIS COLD FRONT BY THE LATTER HALF OF NEXT WEEKEND. WHILE
THERE WILL BE A NOTICEABLE DROP IN TEMPERATURES BEHIND THIS
FRONT...ON THE ORDER OF 10-15F BASED ON 850MB TEMPS...DO NOT EXPECT
A RETURN TO THE CHILLY TEMPERATURES OF LATE...AS ABOVE NORMAL
TEMPERATURES ARE EXPECTED ALL WEEK...GENERALLY IN THE LOWER TO
MIDDLE 70S...WITH THIS NEXT FRONT SIMPLY DROPPING TEMPERATURES A FEW
DEGREES BELOW CLIMATOLOGY FOR EARLY/MID MAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 652 PM CDT SUN MAY 5 2013
HIGH PRESSURE WILL BE NEARLY RIGHT OVERHEAD THROUGH THE
PERIOD...WHICH WILL RESULT IN VERY LIGHT WINDS. THE WIND WILL
GRADUALLY SHIFT FROM NORTHEAST TO SOUTHEAST THROUGH THE PERIOD BUT
COULD BE CALM AND VARIABLE AT TIMES. THE PRIMARY CONCERN WILL
CENTER AROUND THE POSSIBILITY OF FOG DURING THE EARLY MORNING
HOURS AROUND DAWN. THE HRRR MODEL IS SHOWING DENSE FOG...BUT MOST
MODELS ARE INDICATING NO FOG. MIGHT SEE AT LEAST SOME REDUCTION IN
VISIBILITY AND WILL NEED TO WATCH HOW THINGS DEVELOP TONIGHT. WILL
KEEP LOW CLOUDS OUT OF THE TAF FOR NOW...BUT IF FOG FORMS NEAR
DAWN WE COULD QUICKLY FALL INTO IFR OR EVEN LIFR CEILING
CATEGORIES.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...SAR
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1128 PM EDT SUN MAY 5 2013
.SYNOPSIS...
A SLOW MOVING AND COMPLEX STORM SYSTEM WILL CROSS THE CAROLINAS
OVER THE NEXT FEW DAYS. SHOWERS AND ISOLATED THUNDERSTORMS WILL
BE POSSIBLE TONIGHT INTO MONDAY MORNING...THEN AGAIN ON TUESDAY.
WIDESPREAD RAINFALL IS EXPECTED. WEAK HIGH PRESSURE WILL SLOWLY
FILL IN BEHIND THE DEPARTING STORM WEDNESDAY AND THURSDAY. MUCH
WARMER TEMPERATURES ARE EXPECTED LATE IN THE WEEK AS THE REGION
DRIES OUT.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 1100 PM SUNDAY...MAIN FOCUS OF THIS UPDATE REMAINS WITH
THE REDISTRIBUTION OF OVERNIGHT POPS. FOR LATE THIS EVENING...
BASICALLY TOOK THE CURRENT 88D MOSAIC AND EXTRAPOLATED THE
MOVEMENT FOR THE NEXT 3 HRS. AFTERWARD...THE LATEST NAM AND HRRR
MODELS WERE UTILIZED FOR THE REMAINDER OF THE PRE-DAWN HOURS. IN
ESSENCE...THE MAIN CONVEYOR BELT OF PCPN OVER THE ATL WATERS...IS
CURRENTLY AND SLOWLY LIFTING NE WARD. THE PCPN WITHIN THIS BELT
IS MOVING FROM SSE TO NNW...AND PUSHING ONSHORE. AFTER THE
PCPN MOVES ONSHORE...ITS AREAL COVERAGE DECREASES FROM
WIDESPREAD/AREAS OVER THE ADJACENT ATL WATERS TO SCATTERED OVER
LAND AREAS. OF NOTE...DRIER AIR...VIA LATEST WATER VAPOR LOOPS
...IS PARTIALLY FILTERING IN FROM THE SOUTH AND LIKELY HAVING
SOME INPUT FOR WHY PCPN IS NOT AS WIDESPREAD AND/OR INTENSE OVER
LAND. IN GENERAL WILL INDICATE CATEGORICAL POPS CLOSER TO THE
COAST...SLIGHTLY DROPPING THE FURTHER INLAND ONE GOES. QPF HAS
ALSO BEEN FURTHER TWEAKED TO ACCOUNT FOR THE LACK OF WIDESPREAD/
INTENSE PCPN COVERAGE. LATEST MIN TEMPS WERE TWEAKED TO THE HIER
SIDE OF GUIDANCE WITH AROUND 60 INLAND...TO 60-65 AT THE COAST.
HOURLY SFC DEWPOINTS WILL MIMIC HOURLY TEMPS...EXCEPT LOWER BY 1
TO 3 DEGREES DUE TO THE INFLUX OF MOISTURE AND MILD TEMPS UNDER
THE E TO SE FLOW.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...AN OCCLUDED FRONT BENT BACK TO THE NORTHWEST
WILL SWING THROUGH THE EASTERN CAROLINAS MONDAY MORNING
ACCOMPANIED BY A BAND OF MODERATE OR POSSIBLY HEAVY SHOWERS. FOR
EASTERN SC THE BULK OF THE RAIN SHOULD BE DONE BY SUNRISE...BUT IT
WILL PROBABLY TAKE AT LEAST A FEW MORE HOURS FOR RAIN TO CLEAR
ELIZABETHTOWN AND BURGAW. BEHIND THIS FRONT A DRIER AIRMASS WILL
BUILD IN DURING THE DAY ON SOUTH WINDS. (YES...IT HAS BEEN THAT
KIND OF SPRING) THE MONSTER UPPER LOW THAT HAS MOVED ACROSS THE
SOUTHEAST THE PAST COUPLE OF DAYS WILL DRAW NEAR ENOUGH TO THE
REGION DURING THE AFTERNOON TO STEEPEN LAPSE RATES FROM 750 MB UP
THROUGH THE TROPOPAUSE. EVEN WITH LIMITED MOISTURE...WARMING
DAYTIME TEMPERATURES COULD PRODUCE A FEW POP-UP SHOWERS...ENOUGH
TO WARRANT A SMALL POP DURING THE AFTERNOON.
PARTLY CLOUDY TO MOSTLY CLEAR SKIES MONDAY EVENING AND LIGHT WINDS
WILL ALLOW TEMPERATURES TO FALL SURPRISINGLY FAST AND LOWS SHOULD
REACH 50-55 BY 3 AM. CLOUDS SHOULD INCREASE LATE MONDAY NIGHT AS
THE CIRCULATION OF THE UPPER LOW MOVES ACROSS SOUTH CAROLINA AND
WE COULD HAVE SHOWERS REDEVELOPING BY DAYBREAK TUESDAY...
ESPECIALLY ACROSS THE SC PEE DEE REGION.
TUESDAY WILL BE A VERY INTERESTING DAY METEOROLOGICALLY. VERY COLD
MID AND UPPER LEVEL TEMPERATURES FOR THE SEASON WILL PUSH
OVERHEAD DURING THE PEAK OF SOLAR HEATING. FREEZING LEVELS WILL
PLUNGE TO ONLY 8000 FEET...700 MB TEMPS FALL TO -4C...AND 500 MB
TEMPS SHOULD GO AS LOW AS -22C. MODEL FORECAST SOUNDINGS HAVE
CONVECTIVE TEMPERATURES AS LOW AS 63-67 DEGREES...SEVERAL DEGREES
BELOW MY FORECAST HIGHS. THE LIMITING FACTORS WILL BE SUNSHINE AND
LOW LEVEL MOISTURE AS SURFACE DEWPOINTS WILL HOLD IN THE 49-53
RANGE. EVEN GIVEN THESE LIMITATIONS I ANTICIPATE WIDESPREAD
TOWERING CUMULUS DEVELOPMENT WITH 50-70 PERCENT COVERAGE OF
SHOWERS DURING THE DAY. RELATIVELY WEAK UPDRAFT STRENGTH (LIFTED
INDEX NO GREATER THAN -2 AT ANY PRESSURE LEVEL) AND NO STORM
ORGANIZATION (0-6 KM BULK SHEAR <20 KT) SHOULD PRECLUDE LARGE
HAIL...BUT SMALL HAIL IS POSSIBLE GIVEN THE HIGH PROPORTION OF
CAPE WITHIN THE -10C TO -30C REGION AND THE SMALL DISTANCE BETWEEN THE
ENVIRONMENTAL FREEZING LEVEL AND THE GROUND.
THE ATMOSPHERE SHOULD STABILIZE TUESDAY NIGHT AS THE UPPER LOW
DRIFTS JUST NORTH OF THE REGION. A FEW LINGERING SHOWERS MAY CARRY
ON INTO THE EVENING HOURS BUT THE TREND SHOULD BE FOR DRYING
CONDITIONS WITH LOWS IN THE LOWER 50S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 PM SUNDAY...TIGHTLY WOUND LOW PRESSURE SYSTEM WILL
CONTINUE TO MOVE NORTHEAST THROUGH THE CAROLINAS TOWARD THE MID
ATLANTIC COAST WED THROUGH THURS. THE H5 LOW WILL TRACK UP THROUGH
NC INTO VA ON WED. SOME MOISTURE WILL CONTINUE TO WRAP AROUND THE
SYSTEM INTO THE AREA BUT IT LOOKS LIKE BEST MID TO UPPER SUPPORT
WILL LIE TO THE NORTH. CHANCE OF PCP WILL LINGER THROUGH WED BUT
THURS AND FRI LOOK DRIER AS SUBSIDENCE INCREASES ON THE BACK END OF
SYSTEM IN A DEEP W-NW FLOW. THIS DOWNSLOPE FLOW WILL PROMOTE DRIER
WEATHER FOR THURS AND FRI BUT WILL ALSO HELP TO BOOST UP THE TEMPS
BACK TO NORMAL. MID TO UPPER RIDGE WILL BUILD UP THROUGH THE
SOUTHEAST WITH H5 HEIGHT RISES UP TO 580 DM...INCREASING A LITTLE
FURTHER THROUGH SAT BEFORE DEEP MID TO UPPER TROUGH PUSHES EAST BY
THE END OF THE WEEKEND. THIS DEEP MID TO UPPER TROUGH WILL PUSH A
COLD FRONT EAST INTO THE CAROLINAS BY EARLY NEXT WEEK. A DEEP MOIST
RETURN FLOW WILL SET UP AHEAD OF THE FRONT THROUGH THE END OF THE
WEEKEND...INCREASING THE CHC OF SHWRS AND TSTMS. TEMPS IN THE MID
70S ON WED WILL SURPASS THE 80 MARK BY THURS AND WILL REMAIN WARM
THROUGH THE WEEKEND.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
AS OF 00Z...TRICKY FORECAST CONTINUES AS UNSETTLED WEATHER BRINGS
PERIODS OF MVFR AND IFR DUE TO VARYING LOW CIGS...AREAS OF FOG...AND
ISOLATED TO SCATTERED RAIN SHOWERS THROUGH MONDAY AFTERNOON.
OTHERWISE EXPECT VFR.
OVERALL...VFR PREVAILS THIS EVENING WITH EAST-NORTHEAST WINDS AOB 12
KTS AND INTERMITTENT HIGHER GUSTS...BKN/OVC SKY COVERAGE AND
ISOLATED TO SCATTERED LIGHT RAIN SHOWERS MOVING ACROSS THE
AREA...WITH THE EXCEPTION OF KMYR WHICH IS REPORTING MVFR DUE TO
LOWERED CIGS...-RA...AND BR. LATEST RADAR IMAGERY DEPICTS LARGE AREA
OF SHOWERS WHICH ARE SET TO MAKE THEIR WAY ONSHORE...ANTICIPATED TO
AFFECT THE SC COASTAL TERMINALS...WITH A SEPARATE SMALL BATCH OF
SHOWERS ARE MOVING ONSHORE NEAR KILM AS WELL...AND BANDS OF LIGHT
SHOWERS INLAND. TREND OF VARYING CLOUD HEIGHTS WITH PERIODS OF RAIN
WILL CONTINUE THROUGH THE OVERNIGHT HOURS AND WELL INTO THE MORNING
HOURS ON MONDAY. CONFIDENCE IS A BIT LOWERED DUE TO EXACT TIMING AND
LOCATION OF HEAVIER RAINFALL...THUS HAVE KEPT TEMPOS GIVEN LATEST
GUIDANCE. PERIODS OF HEAVY RAINFALL WILL LIKELY CREATE BRIEF PERIODS
OF IFR. FOR MONDAY...RAIN CHANCES WILL CONTINUE WITH CIGS
ANTICIPATED TO LIFT...ALLOWING FOR VFR TO PREVAIL WITH VCSH.
SOUTHEAST WINDS AOB 12 KTS WILL GRADUALLY BECOME SOUTH IN THE
AFTERNOON.
EXTENDED OUTLOOK...AN UPPER LOW MOVES OVER THE REGION TUESDAY WITH
SHOWERS AND ISOLATED THUNDERSTORMS IN THE AFTERNOON AND EVENING.
SMALL HAIL WILL BE POSSIBLE WITH UNUSUALLY LOW FREEZING LEVELS.
ISOLATED SHOWERS CONTINUE WEDNESDAY THROUGH...MAINLY AFTERNOON
HOURS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1115 PM SUNDAY...LATEST SFC PRESSURE PATTERN AND GRADIENT
AHEAD OF THE APPROACHING BOUNDARY FROM THE SOUTH...CONTINUE TO
SUPPORT EAST TO SOUTHEAST 15 TO 25 KT WINDS...WITH FEW GUSTS UP TO
30 KT. CURRENTLY THIS FRONT IS IN THE VICINITY OF CAPE ROMAIN
SC...VIA LATEST SFC OBS. HRRR MODEL DATA SUPPORTS ITS SLOW
PROGRESSION NORTHWARD OVERNIGHT INTO MONDAY. THE ILM SC WATERS WILL
LIKELY SEE WINDS VEERING TO THE S OR SSW 10 TO 15 KT AFTER ITS
PASSAGE DURING THE PRE-DAWN HRS OF MONDAY. IT MAY TAKE UP TO THE
EARLY AFTERNOON HOURS OF MONDAY BEFORE PUSHING ACROSS AND NORTH
OF THE ILM NC WATERS...THIS BASED ON LATEST NAM AND GFS MODEL
OUTPUT.
SIGNIFICANT SEAS WILL CONTINUE TO BE DOMINATED BY A PSEUDO NE-E
DIRECTION SWELL AT 7 TO 8 SECOND DOMINANT PERIODS. OVERALL...SIG
SEAS WILL RANGE BETWEEN 4 AND 8 FT...HIGHEST OUTER WATERS OFF CAPE
FEAR AND WINYAH BAY...AND LOWEST SOUTH OF CAPE FEAR TO LITTLE
RIVER INLET. AS WINDS SUBSIDE AFTER THE PASSAGE OF THE FRONTAL
BOUNDARY...THE IMMEDIATE WIND DRIVEN WAVES WILL BEGIN TO SUBSIDE.
HOWEVER...WAVEWATCH3 INDICATES A NE 10-11 SECOND PERIOD SWELL TO
LITERALLY OCCUPY A LARGE CHUNK OF THE NORTH ATLANTIC BASIN.
LATEST WAVEWATCH3 DOES INDICATE A SLOWER SUBSIDING TREND...WHEREAS
THE LOCALLY PRODUCED SWAN IS A BIT TOO QUICK. PREFER THE SLOWER
TREND. AS A RESULT...HAVE CONTINUED THE SCA MAINLY FOR SIG SEAS
THRU MIDDAY MONDAY ACROSS THE ILM SC WATERS...AND LATE AFTERNOON
MONDAY FOR THE ILM NC WATERS. OVERALL...AVERAGE PERIODS WILL RUN
5.5 SECONDS.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...A NORTHEASTWARD MOVING OCCLUDED FRONT WILL
SWEEP THROUGH THE AREA MONDAY MORNING. THIS IS VERY
UNCHARACTERISTIC OF TYPICAL MAY WEATHER...BUT SEEMS TO BE PAR FOR
THE COURSE FOR THIS SPRING. THE LAST OF THE STRONG EASTERLY WINDS
WE HAVE EXPERIENCED ALL WEEKEND WILL ABATE AS THE FRONT CROSSES
THE AREA. MONDAY AFTERNOON THROUGH TUESDAY NIGHT WILL SEE MUCH
LIGHTER WIND SPEEDS WITHIN THE BAGGY PRESSURE PATTERN AROUND BROAD
LOW PRESSURE OVER THE CAROLINAS. THIS LOW IS ACTUALLY A SURFACE
REFLECTION OF A MUCH MORE POTENT LOW IN THE MID AND UPPER LEVELS
OF THE ATMOSPHERE WHICH SHOULD CREATE SHOWERY AND PERHAPS THUNDERY
WEATHER AGAIN TUESDAY.
THE SMALL CRAFT ADVISORY SHOULD BE ABLE TO DROP FOR THE NC WATERS
EARLY MONDAY AFTERNOON AS LIGHTER WIND SPEEDS WILL NOT SUSTAIN
SEAS AT OR ABOVE 6 FEET. OUTSIDE OF MONDAY MORNING...SEAS SHOULD
BE DOMINATED BY 8 TO 10 SECOND EAST AND SOUTHEAST SWELL...WITH 2-4
FT HEIGHTS.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 300 PM SUNDAY...TIGHTLY WOUND LOW PRESSURE SYSTEM WILL TRACK
UP FROM NORTH CAROLINA INTO THE MID ATLANTIC COAST WED INTO THURS.
AS LOW LIFTS OFF FARTHER TO THE NE THROUGH THURSDAY...THE WINDS WILL
SHIFT AROUND FROM SW TO W WED INTO THURS. WINDS WILL BACK TO THE SW
LATE THURS AS WEAK HIGH PRESSURE BUILDS IN AND WILL SEE INCREASING
RETURN FLOW OUT OF THE SOUTH TO SOUTHWEST AS HIGH SHIFTS OFF SHORE
HEADING INTO THE WEEKEND. WINDS WILL GENERALLY REMAIN AROUND 10 KTS
OR LESS THROUGH THE PERIOD. SEAS WILL GENERALLY STAY IN THE 2 TO 4
FT RANGE WITH A LOWERING TREND OF SEAS THROUGH MID WEEK IN THE OFF
SHORE FLOW AND THEN A REVERSE TREND BY THE WEEKEND IN INCREASING
SOUTHERLY PUSH.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT MONDAY FOR AMZ254-256.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT MONDAY FOR AMZ250-252.
&&
$$
SYNOPSIS...TRA
NEAR TERM...DCH
SHORT TERM...TRA
LONG TERM...RGZ
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
825 PM EDT SUN MAY 5 2013
.SYNOPSIS...
A SLOW MOVING AND COMPLEX STORM SYSTEM WILL CROSS THE CAROLINAS
OVER THE NEXT FEW DAYS. SHOWERS AND ISOLATED THUNDERSTORMS WILL
BE POSSIBLE TONIGHT INTO MONDAY MORNING...THEN AGAIN ON TUESDAY.
WIDESPREAD RAINFALL IS EXPECTED. WEAK HIGH PRESSURE WILL SLOWLY
FILL IN BEHIND THE DEPARTING STORM WEDNESDAY AND THURSDAY. MUCH
WARMER TEMPERATURES ARE EXPECTED LATE IN THE WEEK AS THE REGION
DRIES OUT.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 730 PM SUNDAY...MAIN FOCUS FOR THIS UPDATE WILL BE THE
REDISTRIBUTION OF POPS. FOR THE HOURS OF THIS EVENING...BASICALLY
TOOK THE CURRENT 88D MOSAIC AND EXTRAPOLATED THE MOVEMENT THROUGH
MIDNIGHT. AFTERWARD...THE LATEST NAM AND HRRR MODELS WERE
UTILIZED FOR POPS DURING THE PRE-DAWN HOURS. IN ESSENCE...THE
MAIN CONVEYOR BELT OF PCPN IS CURRENTLY PUSHING ONSHORE ACROSS
THE ILM SC COUNTIES...WITH A SLOW LIFTING NORTHWARD AND ONSHORE
MOVEMENT REACHING THE ILM NC COUNTIES AROUND OR JUST AFTER
MIDNIGHT. WITH PCPN NOT AS A WIDESPREAD AS EARLIER THOUGHT FOR
THIS TIME...HAVE KNOCKED DOWN POPS TO AROUND 80+ WITHIN THE MAIN
PCPN BELT. OF NOTE...DRIER AIR...VIA LATEST WATER VAPOR
IMAGERY...IS FILTERING IN FROM THE SOUTH AND LIKELY HAVING SOME
INPUT FOR WHY PCPN IS NOT AS WIDESPREAD AND/OR INTENSE. QPF HAS
BEEN FURTHER TWEAKED TO ACCOUNT FOR THE LACK OF WIDESPREAD/
INTENSE PCPN COVERAGE. LATEST MIN TEMPS LOOK AOK WITH NO TWEAKS
NEEDED AT THIS POINT.
PREVIOUS DISCUSSION................................................
AS OF 2 PM SUNDAY...LINE OF RAIN/SHOWERS MOVING TOWARD THE AREA
FROM THE SOUTH IS LOOKING LESS IMPRESSIVE WITH EACH PASSING HOUR.
THIS MAY BE A RESULT OF DRY AIR ALOFT...VISIBLE ON WATER VAPOR...
THAT IS CURRENTLY MOVING INTO EASTERN GA. BOTH SATELLITE AND RADAR
TRENDS WOULD SUGGEST THAT THIS DRY AIR COULD SIGNIFICANTLY REDUCE
PRECIPITATION ALONG THE SOUTHERN END OF COLD FRONT. THE MORE
SIGNIFICANT AREA OF PRECIP IS SHIFTING NORTHWEST OF THE
AREA...WHERE THE LOW LEVEL CONVERGENCE IS STRONGER...THERE IS
LESS DRY AIR ALOFT AND THERE ARE SOME MID LEVEL DYNAMICS. HOWEVER
STILL HOLDING ONTO A NARROW WINDOW OF CATEGORICAL POP THIS EVENING
AND OVERNIGHT. WEAK DIVERGENCE ALOFT COMBINED WITH LOW LEVEL
MOISTURE...BOTH GFS/ECMWF SHOW A STRONG THETA E RIDGE MOVING INTO
THE REGION OVERNIGHT...AND LOW LEVEL CONVERGENCE SUGGEST A SHOT
AT PRECIP. ECMWF/CANADIAN BOTH SHOW SOME BAGGINESS IN THE SURFACE
PRESSURE PATTERN AS THE FRONT LIFTS NORTH. SHOULD A WEAK LOW
DEVELOP NEAR OR ALONG THE BOUNDARY IT WOULD ENHANCE RAINFALL
CHANCES. RAINFALL AMOUNTS ARE LIKELY TO BE IN THE 0.25 TO 0.50
INCH RANGE...AIDED BY THE SLOW MOVEMENT OF THE SURFACE FEATURES.
CLOUD COVER AND EAST TO SOUTHEAST BOUNDARY LAYER WINDS FOR MUCH OF
THE NIGHT WILL KEEP LOWS ABOVE CLIMO. MOST COASTAL AREAS WILL
REMAIN ABOVE 60 WITH UPPER 50S ELSEWHERE.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...AN OCCLUDED FRONT BENT BACK TO THE NORTHWEST
WILL SWING THROUGH THE EASTERN CAROLINAS MONDAY MORNING
ACCOMPANIED BY A BAND OF MODERATE OR POSSIBLY HEAVY SHOWERS. FOR
EASTERN SC THE BULK OF THE RAIN SHOULD BE DONE BY SUNRISE...BUT IT
WILL PROBABLY TAKE AT LEAST A FEW MORE HOURS FOR RAIN TO CLEAR
ELIZABETHTOWN AND BURGAW. BEHIND THIS FRONT A DRIER AIRMASS WILL
BUILD IN DURING THE DAY ON SOUTH WINDS. (YES...IT HAS BEEN THAT
KIND OF SPRING) THE MONSTER UPPER LOW THAT HAS MOVED ACROSS THE
SOUTHEAST THE PAST COUPLE OF DAYS WILL DRAW NEAR ENOUGH TO THE
REGION DURING THE AFTERNOON TO STEEPEN LAPSE RATES FROM 750 MB UP
THROUGH THE TROPOPAUSE. EVEN WITH LIMITED MOISTURE...WARMING
DAYTIME TEMPERATURES COULD PRODUCE A FEW POP-UP SHOWERS...ENOUGH
TO WARRANT A SMALL POP DURING THE AFTERNOON.
PARTLY CLOUDY TO MOSTLY CLEAR SKIES MONDAY EVENING AND LIGHT WINDS
WILL ALLOW TEMPERATURES TO FALL SURPRISINGLY FAST AND LOWS SHOULD
REACH 50-55 BY 3 AM. CLOUDS SHOULD INCREASE LATE MONDAY NIGHT AS
THE CIRCULATION OF THE UPPER LOW MOVES ACROSS SOUTH CAROLINA AND
WE COULD HAVE SHOWERS REDEVELOPING BY DAYBREAK TUESDAY...
ESPECIALLY ACROSS THE SC PEE DEE REGION.
TUESDAY WILL BE A VERY INTERESTING DAY METEOROLOGICALLY. VERY COLD
MID AND UPPER LEVEL TEMPERATURES FOR THE SEASON WILL PUSH
OVERHEAD DURING THE PEAK OF SOLAR HEATING. FREEZING LEVELS WILL
PLUNGE TO ONLY 8000 FEET...700 MB TEMPS FALL TO -4C...AND 500 MB
TEMPS SHOULD GO AS LOW AS -22C. MODEL FORECAST SOUNDINGS HAVE
CONVECTIVE TEMPERATURES AS LOW AS 63-67 DEGREES...SEVERAL DEGREES
BELOW MY FORECAST HIGHS. THE LIMITING FACTORS WILL BE SUNSHINE AND
LOW LEVEL MOISTURE AS SURFACE DEWPOINTS WILL HOLD IN THE 49-53
RANGE. EVEN GIVEN THESE LIMITATIONS I ANTICIPATE WIDESPREAD
TOWERING CUMULUS DEVELOPMENT WITH 50-70 PERCENT COVERAGE OF
SHOWERS DURING THE DAY. RELATIVELY WEAK UPDRAFT STRENGTH (LIFTED
INDEX NO GREATER THAN -2 AT ANY PRESSURE LEVEL) AND NO STORM
ORGANIZATION (0-6 KM BULK SHEAR <20 KT) SHOULD PRECLUDE LARGE
HAIL...BUT SMALL HAIL IS POSSIBLE GIVEN THE HIGH PROPORTION OF
CAPE WITHIN THE -10C TO -30C REGION AND THE SMALL DISTANCE BETWEEN THE
ENVIRONMENTAL FREEZING LEVEL AND THE GROUND.
THE ATMOSPHERE SHOULD STABILIZE TUESDAY NIGHT AS THE UPPER LOW
DRIFTS JUST NORTH OF THE REGION. A FEW LINGERING SHOWERS MAY CARRY
ON INTO THE EVENING HOURS BUT THE TREND SHOULD BE FOR DRYING
CONDITIONS WITH LOWS IN THE LOWER 50S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 PM SUNDAY...TIGHTLY WOUND LOW PRESSURE SYSTEM WILL
CONTINUE TO MOVE NORTHEAST THROUGH THE CAROLINAS TOWARD THE MID
ATLANTIC COAST WED THROUGH THURS. THE H5 LOW WILL TRACK UP THROUGH
NC INTO VA ON WED. SOME MOISTURE WILL CONTINUE TO WRAP AROUND THE
SYSTEM INTO THE AREA BUT IT LOOKS LIKE BEST MID TO UPPER SUPPORT
WILL LIE TO THE NORTH. CHANCE OF PCP WILL LINGER THROUGH WED BUT
THURS AND FRI LOOK DRIER AS SUBSIDENCE INCREASES ON THE BACK END OF
SYSTEM IN A DEEP W-NW FLOW. THIS DOWNSLOPE FLOW WILL PROMOTE DRIER
WEATHER FOR THURS AND FRI BUT WILL ALSO HELP TO BOOST UP THE TEMPS
BACK TO NORMAL. MID TO UPPER RIDGE WILL BUILD UP THROUGH THE
SOUTHEAST WITH H5 HEIGHT RISES UP TO 580 DM...INCREASING A LITTLE
FURTHER THROUGH SAT BEFORE DEEP MID TO UPPER TROUGH PUSHES EAST BY
THE END OF THE WEEKEND. THIS DEEP MID TO UPPER TROUGH WILL PUSH A
COLD FRONT EAST INTO THE CAROLINAS BY EARLY NEXT WEEK. A DEEP MOIST
RETURN FLOW WILL SET UP AHEAD OF THE FRONT THROUGH THE END OF THE
WEEKEND...INCREASING THE CHC OF SHWRS AND TSTMS. TEMPS IN THE MID
70S ON WED WILL SURPASS THE 80 MARK BY THURS AND WILL REMAIN WARM
THROUGH THE WEEKEND.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 00Z...TRICKY FORECAST CONTINUES AS UNSETTLED WEATHER BRINGS
PERIODS OF MVFR AND IFR DUE TO VARYING LOW CIGS...AREAS OF FOG...AND
ISOLATED TO SCATTERED RAIN SHOWERS THROUGH MONDAY AFTERNOON.
OTHERWISE EXPECT VFR.
OVERALL...VFR PREVAILS THIS EVENING WITH EAST-NORTHEAST WINDS AOB 12
KTS AND INTERMITTENT HIGHER GUSTS...BKN/OVC SKY COVERAGE AND
ISOLATED TO SCATTERED LIGHT RAIN SHOWERS MOVING ACROSS THE
AREA...WITH THE EXCEPTION OF KMYR WHICH IS REPORTING MVFR DUE TO
LOWERED CIGS...-RA...AND BR. LATEST RADAR IMAGERY DEPICTS LARGE AREA
OF SHOWERS WHICH ARE SET TO MAKE THEIR WAY ONSHORE...ANTICIPATED TO
AFFECT THE SC COASTAL TERMINALS...WITH A SEPARATE SMALL BATCH OF
SHOWERS ARE MOVING ONSHORE NEAR KILM AS WELL...AND BANDS OF LIGHT
SHOWERS INLAND. TREND OF VARYING CLOUD HEIGHTS WITH PERIODS OF RAIN
WILL CONTINUE THROUGH THE OVERNIGHT HOURS AND WELL INTO THE MORNING
HOURS ON MONDAY. CONFIDENCE IS A BIT LOWERED DUE TO EXACT TIMING AND
LOCATION OF HEAVIER RAINFALL...THUS HAVE KEPT TEMPOS GIVEN LATEST
GUIDANCE. PERIODS OF HEAVY RAINFALL WILL LIKELY CREATE BRIEF PERIODS
OF IFR. FOR MONDAY...RAIN CHANCES WILL CONTINUE WITH CIGS
ANTICIPATED TO LIFT...ALLOWING FOR VFR TO PREVAIL WITH VCSH.
SOUTHEAST WINDS AOB 12 KTS WILL GRADUALLY BECOME SOUTH IN THE
AFTERNOON.
EXTENDED OUTLOOK...AN UPPER LOW MOVES OVER THE REGION TUESDAY WITH
SHOWERS AND ISOLATED THUNDERSTORMS IN THE AFTERNOON AND EVENING.
SMALL HAIL WILL BE POSSIBLE WITH UNUSUALLY LOW FREEZING LEVELS.
ISOLATED SHOWERS CONTINUE WEDNESDAY THROUGH...MAINLY AFTERNOON
HOURS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 745 PM SUNDAY...LATEST SFC PRESSURE PATTERN AND GRADIENT
AHEAD OF THE APPROACHING BOUNDARY FROM THE SOUTH...CONTINUE TO
SUPPORT EAST TO SOUTHEAST 15 TO 25 KT WINDS...WITH FEW GUSTS UP
TO 30 KT REMAINING POSSIBLE. CURRENTLY THIS FRONT IS IN THE
VICINITY OF CHARLESTON SC...AND SLOWLY MAKING SOME PROGRESSION
NORTHWARD. THE ILM SC WATERS WILL LIKELY SEE WINDS VEERING TO THE
S OR SSW 10 TO 15 KT AFTER ITS PASSAGE DURING THE PRE-DAWN HRS OF
MONDAY. IT MAY TAKE UP TO THE MIDDAY HOURS OF MONDAY BEFORE
PUSHING ACROSS AND NORTH OF THE ILM NC WATERS...VIA LATEST NAM AND
GFS MODEL OUTPUT. SIGNIFICANT SEAS WILL CONTINUE TO BE DOMINATED
BY A PSEUDO NE-E DIRECTION SWELL AT 7 TO 8 SECOND DOMINANT
PERIODS. OVERALL...SIG SEAS WILL RANGE BETWEEN 4 AND 8
FT...HIGHEST OUTER WATERS OFF CAPE FEAR AND WINYAH BAY...AND
LOWEST END SOUTH OF CAPE FEAR TO LITTLE RIVER INLET. AS WINDS
SUBSIDE AFTER THE PASSAGE OF THE FRONTAL BOUNDARY...THE IMMEDIATE
WIND DRIVEN WAVES WILL BEGIN TO SUBSIDE. HOWEVER...WAVEWATCH3
INDICATES A NE 10-11 SECOND PERIOD SWELL TO LITERALLY OCCUPY A
LARGE CHUNK OF THE NORTH ATLANTIC BASIN. LATEST WAVEWATCH3
INDICATES THIS SLOWER TREND...WHEREAS THE LOCALLY PRODUCED SWAN
IS A BIT TOO QUICK. WITH ALL THIS SAID...DO NOT ANTICIPATE QUICK
SUBSIDING OF THE SEAS ONCE WINDS DIMINISH-SOME. AND AS A
RESULT...HAVE CONTINUED THE SCA MAINLY FOR SIG SEAS THRU MIDDAY
MONDAY ACROSS THE ILM SC WATERS...AND LATE AFTERNOON MONDAY FOR
THE ILM NC WATERS. OVERALL...AVERAGE PERIODS WILL RUN 5.5 SECONDS.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...A NORTHEASTWARD MOVING OCCLUDED FRONT WILL
SWEEP THROUGH THE AREA MONDAY MORNING. THIS IS VERY
UNCHARACTERISTIC OF TYPICAL MAY WEATHER...BUT SEEMS TO BE PAR FOR
THE COURSE FOR THIS SPRING. THE LAST OF THE STRONG EASTERLY WINDS
WE HAVE EXPERIENCED ALL WEEKEND WILL ABATE AS THE FRONT CROSSES
THE AREA. MONDAY AFTERNOON THROUGH TUESDAY NIGHT WILL SEE MUCH
LIGHTER WIND SPEEDS WITHIN THE BAGGY PRESSURE PATTERN AROUND BROAD
LOW PRESSURE OVER THE CAROLINAS. THIS LOW IS ACTUALLY A SURFACE
REFLECTION OF A MUCH MORE POTENT LOW IN THE MID AND UPPER LEVELS
OF THE ATMOSPHERE WHICH SHOULD CREATE SHOWERY AND PERHAPS THUNDERY
WEATHER AGAIN TUESDAY.
THE SMALL CRAFT ADVISORY SHOULD BE ABLE TO DROP FOR THE NC WATERS
EARLY MONDAY AFTERNOON AS LIGHTER WIND SPEEDS WILL NOT SUSTAIN
SEAS AT OR ABOVE 6 FEET. OUTSIDE OF MONDAY MORNING...SEAS SHOULD
BE DOMINATED BY 8 TO 10 SECOND EAST AND SOUTHEAST SWELL...WITH 2-4
FT HEIGHTS.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 300 PM SUNDAY...TIGHTLY WOUND LOW PRESSURE SYSTEM WILL TRACK
UP FROM NORTH CAROLINA INTO THE MID ATLANTIC COAST WED INTO THURS.
AS LOW LIFTS OFF FARTHER TO THE NE THROUGH THURSDAY...THE WINDS WILL
SHIFT AROUND FROM SW TO W WED INTO THURS. WINDS WILL BACK TO THE SW
LATE THURS AS WEAK HIGH PRESSURE BUILDS IN AND WILL SEE INCREASING
RETURN FLOW OUT OF THE SOUTH TO SOUTHWEST AS HIGH SHIFTS OFF SHORE
HEADING INTO THE WEEKEND. WINDS WILL GENERALLY REMAIN AROUND 10 KTS
OR LESS THROUGH THE PERIOD. SEAS WILL GENERALLY STAY IN THE 2 TO 4
FT RANGE WITH A LOWERING TREND OF SEAS THROUGH MID WEEK IN THE OFF
SHORE FLOW AND THEN A REVERSE TREND BY THE WEEKEND IN INCREASING
SOUTHERLY PUSH.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT MONDAY FOR AMZ254-256.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT MONDAY FOR AMZ250-252.
&&
$$
SYNOPSIS...TRA
NEAR TERM...DCH/III
SHORT TERM...TRA
LONG TERM...RGZ
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
102 AM EDT SAT MAY 4 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN CENTERED ALONG THE NEW ENGLAND COAST
INTO THIS WEEKEND. A FRONTAL SYSTEM IN THE MISSISSIPPI VALLEY WILL
MOVE SLOWLY EAST...EVENTUALLY MOVING INTO THE CAROLINAS EARLY NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 950 PM FRIDAY...LATEST RAP MODEL CONTINUES TO SHOW LIGHT
PRECIPITATION REMAINING JUST OFFSHORE AS WEAKNESS IN PRESSURE
FIELD CONTINUES OFFSHORE. WILL CONTINUE A SLIGHT CHC POP TO
ACCOUNT FOR ANY SHOWERS TAKE MAY SNEAK ONSHORE OVERNIGHT. MAIN
CHANGE TO CURRENT FORECAST WILL BE TO LOWER MINIMUM TEMPERATURES A
COUPLE OF DEGREES BASED ON CURRENT FORECASTS AND FAIRLY LOW
DEWPOINT TEMPERATURES IN THE 40S. WITH BREEZY NORTHEAST WINDS...TEMPS
WILL FEEL EVEN COOLER OVERNIGHT...CERTAINLY NOT MAY-LIKE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TODAY/...
AS OF 3 PM FRI...NO SIGNIFICANT PATTERN CHANGE EXPECTED FOR SAT
WITH HIGH PRESSURE TO THE NORTH...LOW TO THE SOUTH...AND UPPER LOW
MOVING INTO THE SE STATES. BREEZY CONDITIONS EXPECTED AGAIN WITH
TIGHTENED GRADIENT. BASED ON LATEST GUIDANCE WILL CONTINUE POPS
FOR SAT...MAINLY E OF HWY 17 WITH CONTINUED ONSHORE FLOW AND WEAK
IMPULSE MOVING THROUGH AHEAD OF THE UPPER LOW. WILL CAP AT SLIGHT
CHANCE FOR NOW. SIMILAR HIGH TEMPS EXPECTED GENERALLY MID 60S TO
LOW 70S.
&&
.LONG TERM /TONIGHT THROUGH FRIDAY/...
OMEGA BLOCK WILL HOLD THRU SAT NIGHT WITH AXIS OF UPPER RDG OVER
THE AREA. BLOCK BREAKS DOWN LATER SUNDAY THRU EARLY NEXT WEEK AS
UPR LOW TO THE W SLIDES E AND UNDERCUTS THE RDG. MUCH OF THE
SUPPORT FOR STEADIER RAIN WILL REMAIN W OF REGION THRU SUN BUT A
SLIGHT TO LOW CHANCE POP OVER SOUTHERN AREAS SAT NIGHT WITH LOW
CHC POPS SPREADING NORTH THRU THE DAY ON SUNDAY AS AN AXIS OF
DEEPER MOISTURE LIFTS NORTH ACRS EASTERN NC. RAIN CHC INCREASE
SUN NIGHT AND ESPCLY MON AS BETTER FORCING AND MOISTURE AHEAD OF
UPPER LOW MOVES INTO REGION. DECENT AGREEMENT AMONG THE LATEST
MODEL RUNS FOR THE UPR LOW DRIFTING THRU THE SE STATES EARLY IN
THE WEEK THEN LIFTING NE ACRS THE FORECAST AREA ON WEDNESDAY SO
EXPECT PROLONGED PERIOD OF UNSETTLED WEATHER THRU MIDWEEK. KEPT
MENTION OF TSRA MAINLY DURING PEAK DIURNAL HEATING CYCLE MON-WED
GIVEN THE COOL POOL ALOFT. BEST LOW LVL WINDS ACROSS REGION MON
HOWEVER INSTAB LOOK WEAK. LOW LVL WINDS BECOME RATHER LIGHT TUE
AND WED HOWEVER WITH COLD POOL ALOFT MAY SEE DECENT CONVECTION
ESPCLY IF GET SOME SUN. OVERALL SEVERE THREATS LOOKS LIMITED BUT
NOT ZERO FIRST PART OF NEXT WEEK. HAVE RAMPED UP POPS TO LIKELY
MOST AREAS ON MON AND MAY NEED TO CONTINUE THE HIGHER POP TREND
INTO TUE IF MODELS CONTINUE IN GOOD AGREEMENT. DRYING TREND WILL
TAKE HOLD LATER IN THE WEEK AS THE UPR LOW FINALLY MOVES WELL NE
OF THE AREA.
TEMPS WILL BE BELOW NORMAL EARLY IN THE WEEK WITH HIGHS MAINLY
UPR 60S TO LOWER 70S. WARMING TREND WILL HIGHLIGHT THE MID TO LATE
WEEK PERIOD WITH AN UPPER RIDGE AGAIN BUILDING OVER THE AREA.
HIGHS MAY REACH NEAR 80 INLAND BY FRIDAY.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /THROUGH SATURDAY/...
AS OF 705 PM FRI...MODERATE CONFIDENCE THAT SOME MVFR AND PERHAPS
IFR CEILINGS WILL OCCUR TOWARD MORNING PER LATEST NUMERICAL
GUIDANCE AND PERSISTENCE FROM THE LAST FEW DAYS WITH LITTLE CHANGE
IN THE AIRMASS. BY MORNING...CONDITIONS WILL LIFT TO VFR AFTER
SUNRISE.
LONG TERM /SAT NIGHT THROUGH WEDNESDAY/...
GENERALLY VFR CONDITIONS SHOULD PREVAIL EARLY IN THE PERIOD BUT
FLYING CONDITIONS WILL DETERIORATE AS SHOWERS BECOME MORE
NUMEROUS LATE IN THE WEEKEND AND ESPECIALLY EARLY NEXT WEEK AHEAD
OF APPROACHING UPPER LOW.
&&
.MARINE...
SHORT TERM /THROUGH SATURDAY/...
AS OF 950 PM FRIDAY...GUSTY NORTHEAST WINDS CONTINUE ON AREA
WATERS WITH 1030+ MB HIGH HOLDING FIRM OVER CENTRAL NEW ENGLAND.
WINDS ARE GUSTING AS HIGH AS 32 KNOTS AT CAPE LOOKOUT WITH SEAS AS
HIGH AS 9 FEET AT THE BUOY 10 MILES NE OF DUCK. HAVE MADE JUST
MINOR TWEAKS TO THE MARINE FORECAST BASED ON CURRENT OBSERVATIONS
AS THE GUSTY WINDS AND ROUGH SEAS WILL CONTINUE THROUGH THE SHORT-
TERM PERIOD.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
POOR BOATING CONDITIONS MOST OF THE PERIOD. GUSTY NE WINDS CONT
SAT NIGHT WITH STRONG HIGH PRES TO THE N AND LOW PRES WELL TO THE
S. THE SFC LOW WILL GRAD LIFT N INTO MON AS UPR LOW APPROACHES
FROM THE W. WINDS WILL GRAD BECOME MORE E SUN TO SE MON WITH
SPEEDS INCREASING INTO THE 15 TO 20 KT RANGE. THE SFC LOW WILL
DRIFT OVER THE AREA BY TUE WITH WINDS BECOMING S/SW LESS THAN 15
KTS. THE LONG DURATION OF ONSHORE FLOW WILL KEEP SEAS ELEVATED
ABOVE SMALL CRAFT ADVISORY THRESHOLDS THRU AT LEAST TUESDAY.
&&
.TIDES/COASTAL FLOODING...
AS OF 1 AM SAT...STRONG NORTHEAST WINDS CONTINUE OVER THE SOUNDS.
EVEN IF WINDS LEVEL OFF A BIT TOWARD MORNING LEVELS WILL LIKELY
REMAIN ELEVATED THROUGH THE DAY. THEREFORE WILL EXTEND COASTAL
FLOOD ADVISORY NOW IN EFFECT FOR CRAVEN AND CARTERET COUNTIES TO
8PM THIS EVENING.
BASED ON BUOY REPORTS...WAVES ARE LIKELY MEETING SURF CRITERIA
ALONG THE COAST NORTH OF CAPE LOOKOUT SO HAVE ISSUED HIGH SURF
ADVISORY THROUGH 8PM THIS EVENING.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...HIGH SURF ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NCZ095-103-
104.
COASTAL FLOOD ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NCZ093-
095.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR AMZ135.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR AMZ130.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT TUESDAY FOR AMZ150-152-154.
SMALL CRAFT ADVISORY UNTIL NOON EDT TUESDAY FOR AMZ156-158.
&&
$$
SYNOPSIS...CQD
NEAR TERM...CTC
SHORT TERM...CQD
LONG TERM...BTC/RF
AVIATION...CTC/BTC/BM
MARINE...CTC/RF/CQD
TIDES/COASTAL FLOODING...HSA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
344 PM CDT SAT MAY 4 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 342 PM CDT SAT MAY 4 2013
MAIN CHALLENGE FOR THIS FORECAST PACKAGE WILL BE PCPN. LATEST
ANALYSIS SHOWS UPPER LOW OVER NRN ARKANSAS. EXPECT SLOWER CHANGES TO
THE LOCAL WEATHER OVER THE NEXT FEW DAYS AS THE OVERALL PATTERN
SHOWS A REX BLOCK OVER WRN CONUS AND ANOTHER BLOCK OVER THE EAST
COAST.
MODELS INITIALIZED WELL AND AND OPTED FOR A BLENDED SOLN. FOR TODAY
AND TONIGHT...MAIN QUESTION IS WHERE AREA OF PCPN WILL SETTLE.
REGIONAL RADAR SHOWS BAND OF PCPN MOVING NORTH INTO WEST CENTRAL AND
NW MINNESOTA. HRRR AND RAP MODELS IN GENERAL AGREEMENT ON PLACEMENT
OF PCPN AND EXPECT MOST PCPN AMOUNTS WILL BE UNDER A QUARTER INCH
OVER THE NEXT 24 HOURS. THE 300K ISENTROPIC ANALYSIS SHOWS SOME
DECENT LIFT AND EXPECTING AN 850MB BAROCLINIC ZONE TO SET UP.
HOWEVER...CONDENSATION PRESSURE DEFICITS WEAK SO FOR NOW WILL ONLY
KEEP LIKELY POPS IN THAT AREA. FOR SUNDAY...LOOKING FOR THE
BAROCLINIC ZONE TO SLOWLY SLIDE SOUTHEAST AND WILL SEE THE END OF
PCPN. OTHERWISE...LOOKING FOR DRIER WEATHER GOING INTO MONDAY.
EXTENSIVE CLOUD COVER WILL KEEP TEMPERATURES A BIT LOWER TODAY
INTO SUNDAY WHEN THE UPPER RIDGE BEGINS SLIDE OVER THE AREA AND A
WARMING TREND BEGINS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 342 PM CDT SAT MAY 4 2013
12 UTC GFS/ECMWF SHOW THE FORECAST AREA IN POORLY DEFINED SPLIT FLOW
MID-WEEK...TRANSITIONING TO NORTHWEST FLOW ALOFT FRIDAY NIGHT INTO
SATURDAY WITH A STRONG CANADIAN COLD FRONT. PRECIPITATION CHANCES
THROUGH FRIDAY WILL DEPEND ON EVOLUTION OF A WEAK CUT-OFF LOW ACROSS
THE SOUTHERN ROCKIES. MOST MODELS PAINT MOST QPF ACROSS THE CENTRAL
PLAINS...BUT SOME DOES MAKE IT FARTHER NORTH. WITH THESE CUT-OFF
LOWS NOT A LOT OF CONFIDENCE...SO WILL KEEP ALL BLEND 20-40 POPS FOR
MOST OF THE WEEK. HOWEVER...THERE SHOULD BE MORE DRY PERIODS THAN
WET. WILL ALSO LIMIT THUNDER MENTION AS INSTABILITY APPEARS TO BE
MINIMAL AT THIS TIME. TEMPERATURES WILL BE ON THE WARM-SIDE OF THE
MOST RECENT THERMAL REGIME WITH HIGHS IN THE 60S AND LOWS MAINLY IN
THE 40S. IT DOES APPEAR CONDITIONS WILL COOL ON SATURDAY WITH
PASSAGE OF THE FRONT FRIDAY NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1258 PM CDT SAT MAY 4 2013
IFR/MVFR CEILINGS TO IMPACT KBJI THROUGH THE TAF PERIOD. MVFR
CEILINGS MAY CLIP KFAR/KTVF THIS AFTERNOON. FOR GFK/KDVL...EXPECT
VFR CONDITIONS. SOME LIGHT RAIN IS STILL POSSIBLE ACROSS NORTHWEST
MN...IMPACTING KBJI AND TO A LESSER EXTENT KTVF AND KFAR...BUT ANY
REDUCTION IN VISIBILITY WILL BE 3 MILES OR BETTER. WINDS WILL REMAIN
FROM THE NORTH-NORTHEAST AROUND 10 KTS...WITH OCCASIONAL AFTERNOON
GUSTS UP TO 20 KTS.
&&
.HYDROLOGY...
ISSUED AT 1258 PM CDT SAT MAY 4 2013
THE BROAD CREST WAVE OF SNOWMELT RUNOFF IS APPROACHING THE
DRAYTON AREA THIS WEEKEND WITH A CREST EXPECTED NEAR 40 FEET.
THE CREST WAVE WILL MOVE INTO THE PEMBINA REGION TOWARD THE END OF
NEXT WEEK WITH A FORECAST NEAR 48.5 FEET...JUST UNDER MAJOR FLOOD
STAGE. A SECOND ROUND OF RUNOFF IS EXPECTED ALONG THE PEMBINA RIVER
WITH ADDITIONAL RISES FORECAST AT WALHALLA AND NECHE THIS NEXT WEEK.
ELSEWHERE RIVERS CONTINUE TO RECEDE AS NO NEW RUNOFF IS OCCURRING
WITH THE DRY WEATHER OVER THE PAST WEEK.
AREAL FLOODING...WILL KEEP THE NORTH DAKOTA WARNINGS GOING AS
OVERLAND FLOODING CONTINUES TO CAUSE ISSUES AND ROAD CLOSURES. AS
FOR THE BELTRAMI AND CLEARWATER COUNTIES WILL CANCEL AFTER
CONFIRMING WITH COUNTY OFFICIALS THAT OVERLAND WATER HAS
DIMINISHED DRAMATICALLY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...HOPKINS
LONG TERM...ROGERS
AVIATION...ROGERS
HYDROLOGY...JK
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
833 PM CDT SUN MAY 5 2013
.UPDATE...
SATELLITE IMAGERY SHOWS CENTER OF UPPER LEVEL LOW OVER NORTHERN
ALABAMA...WHILE RADAR IMAGERY SHOWS BANDS OF RAIN AND A FEW
THUNDERSTORMS CONTINUE TO THE NORTH OF THE CIRCULATION ACROSS
THE SOUTHERN AND EASTERN CWA. HAVE SEEN SEVERAL LIGHTNING STRIKES
AND REPORTS OF PEA SIZE HAIL WITH SOME OF THE STRONGER CONVECTIVE
CORES...AND CANNOT RULE OUT SOME ADDITIONAL STRIKES OR HAIL FOR A
FEW HOURS UNTIL INSTABILITY WANES OVERNIGHT. AFTERNOON HRRR MODEL
RUNS INDICATES UPPER LOW WILL BE MAKING A CYCLOIDAL LOOP OVER THE
NEXT 24 HOURS...MOVING EASTWARD INTO NORTHERN GEORGIA TONIGHT AND
INTO EASTERN TENNESSEE BY SUNRISE...THEN BACK WESTWARD INTO THE
MID STATE TOMORROW BEFORE RETURNING INTO NORTHERN GEORGIA MONDAY
NIGHT. AS THE FIRST PART OF THIS LOOP OCCURS TONIGHT...RAIN
ACROSS SOUTHEASTERN MID TN WILL PIVOT NORTHWESTWARD AROUND THE
CIRCULATION WHICH SHOULD BRING RAIN INTO AT LEAST THE SOUTHEASTERN
PARTS OF THE NASHVILLE METRO...WITH RAIN ALSO SPREADING ACROSS THE
UPPER CUMBERLAND REGION AND PLATEAU THROUGH THE NIGHT. WESTERN
ZONES LOOK TO STAY MOSTLY DRY WITH JUST A FEW SHOWERS. HAVE
UPDATED GRIDS/ZONES MAINLY TO ADJUST TEMPS/POPS BASED ON LATEST
OBS AND ADD MENTION OF THUNDER.
SHAMBURGER
&&
.PREV DISCUSSION... /ISSUED 643 PM CDT SUN MAY 5 2013/
UPDATE...FOR 00Z AVIATION FORECAST
AVIATION...
SEEMS LIKE I`VE BEEN MENTIONING THIS PESKY UPPER LOW FOR DAYS.
WELL...IT`S NOW OVER NORTH ALABAMA WITH COLD CORE TEMPS DOWN TO
-25 CELSIUS AT 500 MBARS. BANDS OF SHOWERS AND ISOLATED
THUNDERSTORMS CONTINUE TO ROTATE AROUND THE CENTER AND WILL WORK
NORTHWEST TOWARD NASHVILLE THIS EVENING. LOOK FOR POOR FLYING
CONDITIONS TO REDEVELOP THIS EVENING AND OVERNIGHT. UPPER LOW
CURRENTLY HITTING WEST COAST WILL EVENTUALLY KICK PESKY UPPER LOW
EASTWARD AND INTO THE CAROLINAS BUT NOT BEFORE TUESDAY. THIS
BASICALLY MEANS AN UNSETTLED PERIOD OF WEATHER FOR THE MID STATE.
BOYD
PREV DISCUSSION... /ISSUED 445 PM CDT SUN MAY 5 2013/
UPDATE...
HAVE UPDATED THE GRIDS/ZONES TO ADD A CHANCE OF THUNDERSTORMS TO
SOUTHERN AREAS INTO THE EVENIGN AS AN ARC OF SCATTERED
THUNDERSTORMS MOVES NORTHWEST INTO THE CWA. OTHER MORE WIDELY
SCATTERED SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL DEVELOP
FURTHER NORTHWARD AS WELL BENEATH COLD AIR ALOFT ASSOCIATED WITH
UPPER LEVEL LOW OVER NORTHERN ALABAMA. A FEW OF THE STORMS WILL BE
CAPABLE OF SMALL HAIL AND SOME GUSTY WINDS. REST OF FORECAST IS
UNCHANGED.
SHAMBURGER
PREV DISCUSSION... /ISSUED 315 PM CDT SUN MAY 5 2013/
DISCUSSION...
UPPER LOW MOVING SLOWLY EASTWARD ACROSS NRN AL. THIS FEATURE...ALONG
WITH THE ASSOCIATED SURFACE TROUGH...IS EXPECTED TO SLOW DOWN AND
POSSIBLY MEANDER TOWARD AND OVER THE MID STATE BY MONDAY AFTERNOON.
IT IS THEN EXPECTED TO MOVE EASTWARD ACROSS THE CAROLINAS ON
TUESDAY. AS A RESULT...OFF AND ON SHOWER ACTIVITY TO CONTINUE
THROUGH MONDAY. UPCOMING QPF AMOUNTS DO NOT LOOK THREATENING WITH
GENERALLY LESS THAN ONE HALF INCH EXPECTED THROUGH MONDAY. A BREAK
FROM THE SHOWER ACTIVITY IS EXPECTED ON TUESDAY.
FOR THE NEAR TERM POPS...GENERALLY 60-70% POPS SHOULD COVER IT
TONIGHT AND MONDAY. FOR THE NEAR TERM TEMPS...WARMING TREND EXPECTED
WITH HIGHS NEAR 70 ON TUESDAY AS MORE IN THE WAY OF SUNSHINE
RETURNS.
IN THE EXT FCST...AS THE PREVIOUSLY MENTIONED UPPER LOW
DEPARTS...UPPER RIDGING AND WARMER WEATHER WILL OCCUR. ONCE THE
RIDGE AXIS REACHES AND MOVES EAST OF MIDDLE TN BY THU NT...SHOWER
AND TSTM CHANCES WILL BE ON THE INCREASE. NEXT FROPA LOOKS LIKE SAT
NT. THUS...HIGHEST POPS OF AROUND 50% OR SO WILL BE FOR THE SAT AND
SUN PERIODS.
AS FOR THE EXT TEMPS...WE`LL SEE ABOVE NORMAL WARMTH THROUGH THE
BULK OF THE PERIOD. HIGHS WILL REACH THE UPPER 70S-LOWER 80S FOR
THU-SAT. COOLER SUNDAY.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
141 AM EDT SAT MAY 4 2013
.SYNOPSIS...
SURFACE HIGH PRESSURE WILL PERSIST OFF THE MID-ATLANTIC COAST
INTO THE WEEKEND...KEEPING A COOL...MARITIME...EAST FLOW ACROSS
THE REGION. A DEEP UPPER LOW WILL MOVE VERY SLOWLY FROM THE
TENNESSEE VALLEY LATE IN THE WEEKEND TO ALONG THE NORTH
CAROLINA OR SOUTHEAST VIRGINIA COAST BY THE MID OR LATE PART OF
NEXT WEEK. AN EXTENDED PERIOD OF LIGHT TO MODERATE
RAIN...OCCASIONALLY HEAVY...CAN BE EXPECTED ALONG WITH A
CONTINUATION OF COOL TEMPERATURES ACROSS THE REGION AS A RESULT.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 930PM...
SURGE OF SC MOVED ACROSS THE AREA FROM THE
EAST...AND LIKE THE WAY THE LATEST RUC HAS CAPTURED THAT FEATURE
SO WILL LEAN ON THAT MODEL FOR THE NEAR TERM SKY CONDITION. WITH
THAT IN MIND...EXPECTING THE INITIAL SC TO MOVE WEST WITH ANOTHER
SURGE OF MOISTURE OVERNIGHT COMBINING WITH DIURNAL EFFECTS AND
UPSLOPE FROM SELY WINDS. THIS SHOULD LEAD TO A BLOOMING LOW CLOUD
DECK AS THE NIGHT GOES ON. WILL TIE THIS INTO LATTER PERIODS OF
THE FORECAST WHICH CONTINUE TO LOOK GOOD.
.PREVIOUS AFD...
HIGH PRESSURE OFF THE CANADIAN MARITIMES WILL CONTINUE TO WEDGE
DOWN THE EAST COAST. MEANWHILE...UPPER LOW CONTINUES TO ROTATE OFF
THE MID-ATLANTIC COAST. A WEAK SHORTWAVE WILL ROTATE ACROSS THE
REGION THIS AFTERNOON INTO TONIGHT. HIGH LEVEL CIRRUS IS SPREADING
ACROSS OUR REGION FROM AN APPROACHING UPPER LEVEL TROUGH AND
FLORIDA LOW PRESSURE CENTER. EASTERLY FLOW WILL CONTINUE TO PUSH
LOW LEVEL MOISTURE INTO OUR REGION TONIGHT INTO SATURDAY. USED A
BLEND OF THE GFS AND CANADIAN FOR CLOUD COVER TONIGHT. WENT WITH
LOWS CLOSE TO THE ADJMET WITH VALUES FROM LOWER 40S IN THE
NORTHWEST MOUNTAINS TO THE UPPER 40S IN THE SOUTHEAST. LOWS WILL
DEPEND PRIMARILY ON CLOUD COVER...AND ADVECTION AS A MODIFIED
MARITIME AIRMASS PROGRESSES INTO OUR REGION. ALLOWED FOR A LIGHT
POP ALONG THE SOUTHERN BLUE RIDGE WHERE CLOUD COVER WILL BE
RICHEST. WITH THE DEEP UPPER LOW TO OUR WEST REACHING THE
TENNESSEE VALLEY AND ENHANCED EASTERLY FLOW...KEPT SATURDAY COOL
WITH INCREASING CLOUDS. MODEL BLENDED THE ECMWF AND NAM FOR HIGH
SATURDAY WITH READINGS FROM LOWER 50S IN THE MOUNTAINS TO THE
UPPER 60S IN THE EAST. CONTINUED THE LIGHT POPS ACROSS THE
SOUTHWEST PORTIONS OF CWA ON SATURDAY.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
AS OF 330 PM EDT FRIDAY...
A CLOSED UPPER LEVEL LOW WILL MEANDER EASTWARD FROM THE LOWER
MISSISSIPPI RIVER VALLEY TOWARD THE SOUTHERN APPALACHIAN MOUNTAINS
DURING SATURDAY NIGHT INTO SUNDAY. POPS WERE BUMPED UPWARD TO
CATEGORICAL GIVEN THE GOOD AGREEMENT IN SPACE AND TIME BETWEEN THE
GFS AND THE ECMWF MODELS. IT WOULD NOT BE SURPRISING TO SEE A COUPLE
INCHES OF RAIN BETWEEN SATURDAY NIGHT AND MONDAY NIGHT ALONG THE
FAVORED UPSLOPE AREAS OF THE SOUTHERN BLUE RIDGE DUE TO DECENT
SOUTHEAST FLOW FROM A MOIST LOW LEVEL JET. WINDS COULD BECOME A
LITTLE GUSTY ALONG THE RIDGES DUE TO THIS JET.
THIS PROLONGED SPELL OF RAIN WILL MOST LIKELY COME IN OCCASIONAL
BANDS SPIRALING AROUND THE LOW. SOME OF THE HEAVIER BURSTS OF
RAINFALL COULD PRESENT A FLOODING ISSUE FOR SMALL RIVERS AND STREAMS
IN NORTHWEST NORTH CAROLINA AND SOUTHWEST VIRGINIA. FOG...LOW
CLOUDS...AND DRIZZLE SHOULD ACCOMPANY THE REMAINING PERIODS BETWEEN
BANDS. TEMPERATURES WERE HELD TO A SMALLER DIURNAL RANGE THAN
INDICATED IN THE MOS GUIDANCE...WITH HIGHS KEPT SEVERAL DEGREES
COOLER DUE TO THE PERSISTENT EASTERLY FLOW AT THE SURFACE.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 330 PM EDT FRIDAY...
BY TUESDAY...THE CUT OFF UPPER LEVEL LOW WILL WOBBLE EASTWARD OVER
THE CAROLINAS...AND APPROACH THE OUTER BANKS ON TUESDAY NIGHT. BOTH
THE 12Z GFS AND THE 00Z ECMWF ARE IN FAIRLY GOOD AGREEMENT WITH THE
TRACK AND RAINFALL COVERAGE OVER THE CWA...SO POPS WERE BUMPED
UPWARD TO LIKELY FOR TUESDAY BEFORE TAPERING TO CHANCE POPS ON
WEDNESDAY. THE UPPER LEVEL LOW WILL EVENTUALLY MERGE WITH THE
NORTHERN STREAM TO END THIS PROLONGED BLOCKING PATTERN AROUND
THURSDAY...BUT THE TIMING MAY BE A LITTLE OPTIMISTIC GIVEN HOW
SLOWLY THESE FEATURES TEND TO MOVE.
TEMPERATURES SHOULD INCREASE LATE IN THE WEEK WITH MORE SUNSHINE AND
A SOUTHWEST FLOW. HOWEVER...CHANCES OF SHOWERS WILL NOT SUBSIDE
COMPLETELY...DUE TO AN UPPER LEVEL TROUGH APPROACHING FROM THE WEST
BY FRIDAY. INSTABILITY APPEARS LOW IN THE MODEL SOUNDINGS DESPITE
THE INCREASING TEMPERATURES AND DEWPOINTS...SO THUNDER WAS HELD OUT
OF THE FORECAST FOR NOW...BUT THOSE CHANCES WILL BE MONITORED IN
FUTURE UPDATES. OVERALL...TEMPERATURES WERE KEPT TOWARD THE COOLER
SIDE OF GUIDANCE DUE TO THE ABUNDANT CLOUDINESS AND MOISTURE THAT
WILL BE EXPERIENCED IN THIS EXTENDED PERIOD.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 130 AM EDT SATURDAY...
SE FLOW REMAINS STRONG EARLY THIS MORNING ALTHOUGH LOWER CLOUDS
REMAIN MORE SCATTERED THAN BKN EXCEPT AROUND HSP. WINDS WILL BE
GUSTY MOST OF THE THIS PERIOD AS GRADIENT REMAINS TIGHT BETWEEN
SFC HIGH OVER NEW ENGLAND AND THE LOW OVER THE MIDWEST. THINK A
SMALL PERIOD OF BKN MVFR CIGS ARE POSSIBLE THIS MORNING AT BCB/ROA
BUT OVERALL LOOKS LIKE VFR CIGS WILL BE THE RULE THIS PERIOD.
EXTENDED AVIATION DISCUSSION...MAIN ATTENTION WILL BE APPROACHING
CLOSED LOW FROM THE MIDWEST/TN VALLEY REGION LATE IN THE
WEEKEND/EARLY NEXT WEEK. MODELS CONTINUE TO SUGGEST THAT LOWER
CIGS WILL ARRIVE BY SUNDAY AFTERNOON WITH AN EXTENDED PERIODS OF
RAIN AND WIDESPREAD IFR OR WORSE CIGS/VSBYS...ALONG WITH GUSTY
E-SE WINDS PERSISTING INTO TUESDAY AT THIS POINT. CONDITIONS
SHOULD GRADUALLY IMPROVE TO MVFR TOWARD MID AND LATE WEEK...WITH
RAINFALL BECOMING MORE SHOWERY IN NATURE WITH POSSIBLY ISOLD
AFTERNOON TSRA TO ADD TO THE PICTURE AT THAT TIME AS WELL.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...RAB
NEAR TERM...KK/MBS
SHORT TERM...PW
LONG TERM...PW
AVIATION...CF/WP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
639 PM CDT SUN MAY 5 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 230 PM CDT SUN MAY 5 2013
MAIN FORECAST CONCERN IS ON ANY FOG POTENTIAL TONIGHT
CURRENTLY AS OF 19Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED UPPER HIGHS IN SOUTHERN BRITISH COLUMBIA AND OVER THE GREAT
LAKES REGIONS...WHILE UPPER LOWS WERE PRESENT JUST WEST OF SAN
FRANSISCO CA...OVER CENTRAL SOUTH DAKOTA AND OVER ALABAMA. THIS
SETUP RESULTS IN LITTLE FLOW IN THE UPPER LEVELS ACROSS THE NORTHERN
U.S.. THERE REMAINS SCATTERED-BROKEN HIGH CLOUDS OVER THE AREA...ON
THE SOUTHWEST SIDE OF THE UPPER HIGH. OTHERWISE...A DRY AIRMASS HAS
BEEN ADVECTING INTO THE FORECAST AREA FROM THE EAST...WITH THE 12Z
GRB SOUNDING REFLECTIVE OF THE DRY AIR. THE COMBINATION OF THE DRY
AIR...850MB TEMPS AROUND 8C...AND THE SUN HAS ALLOWED TEMPERATURES
TO CLIMB INTO THE 65 TO 75 DEGREE RANGE WHERE SNOW DOES NOT EXIST.
MEANWHILE...DODGE CENTER WHICH STILL HAS A DECENT AMOUNT OF SNOW ON
THE GROUND...TEMPERATURES ARE STUCK IN THE MID 40S. REGARDING THE
SEA LEVEL PRESSURE PATTERN...HIGH PRESSURE STRETCHED ACROSS NORTHERN
MINNESOTA INTO NORTHERN ONTARIO...WHILE AN INVERTED TROUGH WAS
PRESENT OVER WESTERN WISCONSIN...EXTENDING NORTH FROM LOW PRESSURE
IN ALABAMA.
LITTLE CHANGE IS PROGGED TO THE UPPER LEVEL PATTERN ACROSS THE
UPPER MIDWEST INTO THE GREAT LAKES WITH PERHAPS JUST A SLIGHT
BREAKDOWN OF THE UPPER RIDGE OVER THE GREAT LAKES. AS A
RESULT...NOT EXPECTING MUCH CHANGE BETWEEN WHAT HAPPENED TODAY TO
WHAT WILL HAPPEN TOMORROW. IF ANYTHING...WINDS SHOULD BE A BIT
LIGHTER WITH THE HIGH PRESSURE AREA OVER NORTHERN ONTARIO PROGGED
TO DRIFT SOUTH INTO NORTHERN WISCONSIN BY 00Z TUESDAY. PER
200-300MB RH PROGS...LOOKS LIKE THE SCATTERED TO BROKEN HIGH
CLOUDS WILL PERSIST ACROSS THE AREA THROUGH MONDAY. THESE CLOUDS
COMBINED WITH LIGHT NORTHERLY DRY ADVECTION SHOULD PRECLUDE ANY
FOG DEVELOPMENT TONIGHT...DESPITE PERSISTENCE FROM SREF PROGS AND
NMM CORE MODELS WHICH CONTINUE TO SHOW TOO HIGH OF DEWPOINTS. EVEN
WORSE...THE 05.12Z NAM AND NCEP HIRES NMM MODELS BASICALLY HAD FOG
AND TEMPS AROUND 34F AT KRST ALL DAY TODAY. NCEP HIRES ARW
MODELS...WHICH ARE DOING BETTER WITH DEWPOINTS BUT STILL TOO
HIGH...THIS TIME TONIGHT DO NOT SHOW FOG. REGARDING LOW...THE HIGH
CLOUDS TONIGHT WILL KEEP TEMPERATURES UP SOMEWHAT...BUT THE DRY
AIRMASS ALSO SUPPORTS READINGS FALLING...ESPECIALLY IN THE TYPICAL
COLD SPOTS. TRENDED TOWARDS THE COLDER SIDE OF GUIDANCE. ON
MONDAY...850MB TEMPS ARE STILL HOLDING AROUND 8C...SO EXPECTING
HIGHS SIMILAR TO TODAY. ONLY DIFFERENCE WOULD BE OUT WEST WHERE
LESSER SNOW SHOULD ALLOW FOR WARMER TEMPERATURES.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 230 PM CDT SUN MAY 5 2013
MONDAY NIGHT THROUGH WEDNESDAY...ONLY MAIN CONCERN FROM A
PRECIPITATION PERSPECTIVE IS THE UPPER LOW SITUATED OVER CENTRAL
SOUTH DAKOTA. HANDLING OF THIS UPPER LOW HAS BEEN VERY PROBLEMATIC
RUN TO RUN AND BETWEEN MODEL TO MODEL. THERE HAS BEEN A GENERAL SLOW
DOWN IN BRINGING THIS UPPER LOW TOWARDS THE AREA...WHICH MAKES SENSE
AS IT IS CAUGHT IN A LACK OF FLOW BETWEEN THE NORTHERN AND SOUTHERN
STREAMS. THE WAY MODELS EVENTUALLY BRING IT TOWARDS THE AREA IS FROM
A NORTHERN STREAM TROUGH DROPPING INTO SOUTH CENTRAL CANADA...THUS
PICKING UP THE UPPER LOW. THE 05.12Z GFS IS THE FASTEST SOLUTION...
AND QUITE A BIT FASTER COMPARED TO ITS 05.06Z GFS...IMPACTING THE
AREA DURING THE DAY WEDNESDAY. 05.12Z NAM/UKMET/CANADIAN AND
05.00Z/05.12Z ECMWF ARE SLOWER. BELIEVE SLOWER IS THE WAY TO
GO...WHICH WOULD KEEP ANY PRECIPITATION FORCED BY THE UPPER LOW
MOSTLY WEST OF THE AREA. THUS HAVE KEPT ANY PRECIPITATION CHANCES
LOW AND CONFINED TO WESTERN SECTIONS. OTHERWISE...DRY CONDITIONS
WILL PREVAIL UNDER THE INFLUENCE OF HIGH PRESSURE AND LITTLE IN THE
WAY OF FLOW ALOFT. 850MB TEMPS HOLD IN THE 8-10C RANGE FOR BOTH
TUESDAY AND WEDNESDAY...WHICH SHOULD YIELD HIGHS IN THE 70S BOTH
DAYS WITH JUST SOME SCATTERED CLOUDS AROUND. A DRY AIRMASS
ACCOMPANYING THE HIGH...LIGHT WINDS AND THE SCATTERED CLOUDS LIKELY
TO ALLOW FOR DECENT COOLING AT NIGHT. STAYED TOWARDS THE COLD END OF
GUIDANCE...PARTICULARLY FOR THE TYPICAL COLD SPOTS.
WEDNESDAY NIGHT THROUGH SUNDAY...FOCUS AT THE BEGINNING OF THIS
PERIOD REMAINS ON THE UPPER LOW AND A COLD FRONTAL BOUNDARY THAT
LOOKS TO ACCOMPANY THIS UPPER LOW...AS WELL AS THE AFOREMENTIONED
NORTHERN STREAM SHORTWAVE TROUGH. AS MENTIONED THE 05.12Z GFS WAS A
BIT FAST WITH THE UPPER LOW...THUS PREFER THE SLOWER 05.00Z/05.12Z
ECMWF. EITHER SOLUTION REQUIRES AT LEAST SOME CHANCES OF SHOWERS AND
THUNDERSTORMS WITH THE COLD FRONTAL PASSAGE AND EVENTUALLY UPPER
LOW. IT APPEARS THE COLD FRONT WILL SLOWLY DROP SOUTHEAST THROUGH
THE AREA WEDNESDAY NIGHT THROUGH THURSDAY...WITH THE BEST CHANCES OF
PRECIPITATION OVER SOUTHERN PORTIONS OF THE AREA CLOSER TO THE
PROGGED UPPER LOW. CANADIAN HIGH PRESSURE BUILDS IN FOR
FRIDAY...YIELDING DRIER AND SLIGHTLY COOLER CONDITIONS WITH 850MB
TEMPS OF 6-8C.
MODELS CONTINUE TO HINT AT BIG CHANGES FOR THE WEEKEND WITH THE
05.12Z ECMWF/GFS/CANADIAN/GFS ENSEMBLES AND ECMWF ENSEMBLES ALL
SHOWING A POTENT TROUGH DROPPING DOWN INTO THE WESTERN GREAT LAKES
REGION. THIS TROUGH CURRENTLY IS IN THE ARCTIC NORTH OF SIBERIA...
THUS EXPECTING A DECENT COLD SHOT. IN FACT...850MB TEMPS ARE PROGGED
TO PLUMMET TO -4 TO -6C BY 12Z SUNDAY OVER THE FORECAST AREA. A COLD
FRONT LOOKS TO RACE AHEAD OF THIS POTENT TROUGH...WHICH MEANS
BETWEEN THE TWO A LIKELY DEFORMATION BAND OF LIGHT PRECIPITATION.
THUS...CHANCES OF SHOWERS ARE IN THE FORECAST FOR SATURDAY.
TEMPERATURES SATURDAY WILL BE TRICKY...ALL DEPENDING ON WHEN THE
FRONT COMES THROUGH. IF IT IS SLOWER...850MB TEMPS OF 6-8C WOULD
SUPPORT MOST LOCATIONS TOPPING OUT INTO THE 60S AND POSSIBLY EVEN
LOW 70S LIKE THE 05.00Z ECMWF. ON THE OTHER HAND...A FASTER SOLUTION
LIKE THE 05.12Z ECMWF/CANADIAN WOULD BE IN THE 50S...OR COLDER. FOR
NOW WENT WITH THE COMPROMISE AND FOLLOWED A BLEND OF GUIDANCE FOR
TEMPERATURES. DEFINITELY COLDER BUT DRIER FOR SUNDAY AS THE 850MB
THERMAL TROUGH AND CANADIAN AIR MOVE IN. HIGHS LIKELY TO ONLY TOP
OUT IN THE 50S ON SUNDAY...A GOOD 15 DEGREES OR SO BELOW NORMAL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 639 PM CDT SUN MAY 5 2013
PATCHY BR WILL REDUCE VISIBILITIES TO AROUND 4 SM STARTING AROUND
08Z AT KRST AND 09Z AT KLSE. THE BR WILL LINGER THROUGH 14Z MONDAY
MORNING THEN DISSIPATE AS MIXING INCREASES. OTHERWISE...VFR
CONDITIONS ARE EXPECTED. CIRRUS WILL CONTINUE TO DRIFT FROM
SOUTHEAST TO NORTHWEST ACROSS THE REGION...STREAMING OFF OF A LOW
PRESSURE SYSTEM CENTERED OVER NORTHERN ALABAMA/TENNESSEE...WITH
CLOUD BASES AROUND 20KFT. A FEW CUMULUS...WITH CLOUD BASES AROUND
5KFT..WILL LINGERS INTO EARLY THIS EVENING THEN DISSIPATE WITH THE
LOSS OF DAYTIME HEATING. HIGH PRESSURE WILL GRADUALLY BUILD INTO
THE AREA OVERNIGHT WITH WINDS BECOMING LIGHT OUT OF THE NORTH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
600 PM CDT SAT MAY 4 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 236 PM CDT SAT MAY 4 2013
AN UPPER LEVEL DISTURBANCE ROTATING AROUND THE UPPER LOW CAUSED
SOME SHOWERS TO DEVELOP LATE THIS MORNING/EARLY THIS AFTERNOON.
MOST OF THESE SHOWERS WERE NOW WEST OF WOOD AND MARATHON COUNTY.
COULD NOT RULE OUT A STRAY SHOWER UNTIL 21Z...BUT WILL NOT
HIGHLIGHT IN A PRE-FIRST PERIOD TO THE ZONE FORECAST TO ACCOUNT
FOR THIS REMOTE POSSIBILITY.
ATTENTION THEN TURNS TO THE FOG. NUMERICAL GUIDANCE NOT INDICATIVE
OF DENSE FOG LATE TONIGHT OUTSIDE THE FAR NORTH. HOWEVER...DEW POINTS
MAINLY IN THE 40S TO AROUND 50 THIS AFTERNOON...PARTLY CLOUDY SKIES
AND LIGHT WINDS TONIGHT...AND A COLDER THAN NORMAL SOIL TEMPERATURES
LEAD ME TO THINK THERE WILL BE MORE FOG/DENSE FOG AROUND TONIGHT THAN
THE NUMERICAL GUIDANCE SUGGEST. WILL MENTION AREAS OF DENSE FOG ACROSS
THE FAR NORTH AND AREAS OF FOG WITH LOCALLY DENSE FOG POSSIBLE ELSEWHERE.
ANY FOG SHOULD BURN OFF BY MID MORNING ON SUNDAY. ANOTHER MILD DAY
IS EXPECTED WITH HIGHS WELL INTO THE 60S TO LOWER 70S. A WEAK BOUNDARY
IS EXPECTED TO DROP SOUTH IN NORTHERN WISCONSIN SUNDAY AFTERNOON. THIS
BOUNDARY COULD TRIGGER SOME ISOLATED/SCATTERED SHOWERS GENERALLY NORTH
OF A WAUSAU TO WAUSAUKEE LINE.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 236 PM CDT SAT MAY 4 2013
THE REMNANTS OF THE SYSTEM WHICH CAUSED HAVOC OVER THE MID SECTION
OF THE COUNTRY THE LATER HALF OF THE PREVIOUS WORK WEEK CONTINUES
TO CHURN OVER THE SOUTHEAST STATES AND SLOWLY WEAKEN THROUGH
TUESDAY. ANOTHER UPPER LOW SYSTEM IS PROGGED TO DROP INTO SOUTHWEST
STATES EARLY IN THE NEW WORK WEEK AS WELL.
LOCALLY A RIDGE OF HIGH PRESSURE WILL EXTEND OVER THE GREAT LAKES
REGION TROUGH AT LEAST MID WEEK. ABOVE NORMAL AND MAINLY DRY
CONDITIONS CAN BE EXPECTED THROUGH MID WEEK. WEAK MID LEVEL
CONVERGENCE OVER THE NORTHERN PLAINS AND NORTHWEST WESTERN MAY BE
CLOSE ENOUGH TO PARTS OF NORTH CENTRAL AND CENTRAL WISCONSIN TO
GENERATE AN ISOLATED SHOWER IN THE AFTERNOON EACH MONDAY AND
TUESDAY SINCE MARGINAL INSTABILITY REMAINS IN THIS AREA. SLIGHTLY
COOLER TEMPS ALOFT WERE PRODUCING TOTAL TOTALS IN THE MID TO UPPER
40S. HOWEVER SUBSIDENCE FROM THE EAST WINDS WITH THE UPPER RIDGE
MAY LOWER HUMIDITY TO KEEP THE SHOWERS IN CHECK. AS A RESULT WILL
KEEP THE FORECAST DRY THROUGH MID WEEK.
PROGS BEGIN TO INTRODUCE A PATTERN CHANGE WITH LIFTING THE
SOUTHWEST U.S. LOW INTO THE MID SECTION OF THE COUNTRY BEFORE
DEVELOPING A DEEPER SHORT WAVE TROUGH THE LATER HALF OF THE WEEK.
PCPN CHANCES WILL BE ON THE INCREASE OVER AT LEAST THE SOUTH HALF
OF THE STATE AS THE TROUGH DRAGS A LOW PRESSURE SYSTEM OVER IOWA
AND ILLINOIS WHILE HIGH PRESSURE DROPS INTO THE GREAT LAKES FROM
THE NORTH. A COLDER SURGE OF AIR WITH A FROPA MAY DROP INTO THE
REGION LATE SATURDAY INTO SATURDAY NIGHT. A FEW RAIN/SNOW? SHOWERS
WILL BE POSSIBLE ACROSS NORTH NEXT WEEKEND.
THE RIDGE OF HIGH PRESSURE WITH LIGHT WINDS AND CLEAR SKIES MAY
PROVIDE A FEW NIGHTS WITH FOG.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 557 PM CDT SAT MAY 4 2013
MAIN ISSUE IS THE POTENTIAL FOR FG FORMATION TNGT. RAP VSBY FCST
FOCUSES ON THE FAR N...WHERE THERE IS STILL SOME LINGERING
SNOW/ICE COVER...AND HAS MVFR CONDITIONS ELSEWHERE. THAT/S SIMILAR
TO WHAT/S IN THE GOING FCST...SO WL STAY THE COURSE WITH THAT FOR
NOW AND SEE HOW DPWTS REACT THIS EVENING. /PARTS OF CENTRAL WI
MIXED INTO DRIER AIR ALOFT THIS AFTN./
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....ECKBERG
LONG TERM......TDH
AVIATION.......SKOWRONSKI
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
306 PM CDT SAT MAY 4 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 306 PM CDT SAT MAY 4 2013
MAIN FORECAST CONCERN IS ON FOG AND DENSE FOG POTENTIAL TONIGHT
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED UPPER LOWS OVER NORTHERN CALIFORNIA AND IN ARKANSAS...WHILE
AN UPPER HIGH WAS PRESENT ACROSS MUCH OF THE GREAT LAKES. FLOWING
BETWEEN THE ARKANSAS UPPER LOW AND THE GREAT LAKES UPPER HIGH WAS A
SHORTWAVE OVER CENTRAL WISCONSIN. DPVA AHEAD OF THIS SHORTWAVE
COMBINED WITH DAYTIME HEATING AND SOME EVAPOTRANSPORATION HAS AIDED
IN SHOWERS NORTH OF I-94. FARTHER SOUTH...SCATTERED SHOWERS ARE ALSO
PRESENT ACROSS PORTIONS OF NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN...AIDED BY INSTABILITY PRODUCED BY DEWPOINTS CLIMBING INTO
THE LOW 50S AND SOME COOLER TEMPS ALOFT. REGARDING TEMPERATURES...
THEY VARY GREATLY ACROSS THE FORECAST AREA...FROM THE 40S IN
ROCHESTER TO 60S ACROSS MUCH OF SOUTHWEST INTO CENTRAL WISCONSIN.
THE WARMER TEMPERATURES ARE A RESULT OF MORE SUN AND AN EASTERLY
FLOW OF WARMER AIR COMING OUT OF THE UPPER HIGH. 12Z GRB SOUNDING
SHOWED 900MB TEMPS OF +14C...COMPARED TO +5C AT MPX. BOTH SOUNDINGS
HAD AN INVERSION...BUT MPX WAS MUCH DEEPER AND THUS COMBINED WITH
THE CLOUDS WAS HELPING TO KEEP TEMPERATURES COOLER IN SOUTHEAST MN.
THE DEEPER INVERSION ALSO HAS HELPED TRAPPED PLENTY OF LOW LEVEL
MOISTURE...INCLUDING THAT FROM THE MELTING SNOWPACK...WHICH RESULTED
IN LOW VISIBILITIES OVER NORTHEAST IOWA...SOUTHEAST MINNESOTA AND
EVEN NORTH CENTRAL WISCONSIN THIS MORNING.
VERY LITTLE CHANGE IS FORECAST IN THE UPPER LEVEL PATTERN THROUGH
SUNDAY...EXCEPT FOR SOME UPPER RIDGING TRYING TO BUILD WESTWARD
THROUGH THE FORECAST AREA FROM THE UPPER HIGH. THIS UPPER RIDGING
SHOULD HELP TO KEEP THE FORECAST AREA DRY THROUGH SUNDAY AFTER ANY
SHOWERS FROM THIS AFTERNOON DISSIPATE WITH LOSS OF HEATING. THE
BIG ISSUE TONIGHT IS FOG. CONTINUING SNOW MELT OVER WESTERN AND
FAR NORTHERN PORTIONS OF THE AREA WILL HELP TO KEEP THE LOW LEVELS
OF THE ATMOSPHERE MOIST. MEANWHILE...MODELS MAINTAIN AN INVERSION
OVER THE SNOW PACK AREAS...WHICH MAKES SENSE WITH THE EASTERLY
FLOW OF WARMER AIR ALOFT ABOVE A NORTH-NORTHEAST FLOW OF COOL AIR
AT THE SURFACE. GIVEN THAT 1/4SM FOG FORMED THIS MORNING AND WINDS
ARE GOING TO BE EVEN LIGHTER...SITUATION SEEMS VERY FAVORABLE FOR
FOG AND EVEN DENSE FOG. ADDITIONALLY...SOME CLEARING COULD TRY TO
WORK IN BASED ON VISIBLE SATELLITE TRENDS...MAKING FOG EVEN MORE
FAVORABLE. SREF PROBABILITIES FOR VISIBILITY LESS THAN 1 MILE ARE
MUCH MORE EXPANSIVE AND HIGHER TONIGHT COMPARED TO THIS
MORNING...AND THE 04.00Z/06Z/12Z HIRES ARW/NMM ALL SHOW MORE FOG
TOO THAN THIS MORNING. LATEST HRRR/RAP ALSO DEVELOP FOG OVER THE
SNOW PACK. GIVEN THESE SIGNALS...HAVE INCREASED FOG COVERAGE AND
ISSUED A DENSE FOG ADVISORY...CONFINED TO THE AREAS WITH MELTING
SNOW PACK. COMBINATION OF HIGHER DEWPOINTS TONIGHT AND COME CLOUDS
WILL RESULT IN A WARMER NIGHT TONIGHT. WARMER TEMPERATURES ARE
ALSO ON TAP TOMORROW WITH MORE SUN LIKELY AS DRIER AIR COMING OUT
OF THE UPPER HIGH ADVECTS WESTWARD.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 306 PM CDT SAT MAY 4 2013
SUNDAY NIGHT THROUGH TUESDAY...NOT MUCH TO TALK ABOUT WITH REGARDS
TO THE UPPER LEVEL PATTERN. THE UPPER HIGH THAT IS OVER THE GREAT
LAKES SLOWLY BREAKS DOWN IN RESPONSE TO A SHORTWAVE TROUGH TRACKING
ACROSS NORTHERN ONTARIO COME MONDAY. STILL...THE FORECAST AREA JUST
SITS IN A LACK OF ANY UPPER LEVEL FLOW...SPLIT BETWEEN A SOUTHERN
STREAM TRACKING ACROSS THE SOUTHERN U.S. AND THE NORTHERN STREAM
WELL UP IN CANADA. MEANWHILE AT THE SURFACE...HIGH PRESSURE
CURRENTLY PRESENT OVER NORTHERN ONTARIO IS PROGGED TO BUILD SOUTH
INTO THE AREA DURING THIS PERIOD. DRYING AIR WITH THIS HIGH PRESSURE
AREA COMBINED WITH LACK OF ANY FLOW ALOFT WILL HELP TO KEEP THE
FORECAST AREA DRY. MAIN CONCERN AGAIN IS FOG. SREF PROBABILITIES FOR
VISIBILITY LESS THAN 1 MILE SHOOT BACK UP AGAIN SUNDAY NIGHT...
CONFINED TO THE SNOW PACK AREA. ONE QUESTION WOULD BE IS HOW MUCH
SNOW IS LEFT AFTER MELTING FROM THIS WEEKEND. HOWEVER...SOILS ARE
LIKELY GOING TO BE MOIST...AND WITH LIGHT WINDS AND CLEARING FROM
THE HIGH PRESSURE AREA BUILDING IN...RECIPE LOOKS GOOD AGAIN FOR FOG
AND EVEN DENSE FOG. MAY EVEN SEE FOG AGAIN MONDAY NIGHT...DEPENDING
IF THE SOIL IS STILL MOIST.
REGARDING TEMPERATURES THROUGH TUESDAY...850MB TEMPS ARE PROGGED TO
HOLD AROUND 8C FOR MONDAY AND THEN CLIMB TO NEAR 10C BY THE END OF
THE DAY TUESDAY. THESE READINGS ARE 0.5 TO 1 STANDARD DEVIATION
ABOVE NORMAL. BOTH DAYS SHOULD SEE QUITE A BIT OF SUN BEING IN
PROXIMITY TO THE SURFACE HIGH...THUS THINKING MIXING TO 850MB WILL
NOT BE A PROBLEM. THIS RESULTS IN HIGHS MAINLY IN THE LOW 70S ON
MONDAY AND LOW TO MID 70S ON TUESDAY. DID KEEP THE ROCHESTER AREA A
LITTLE COOLER ON MONDAY DUE TO WETTER SOIL. LIGHT WINDS AND DRY AIR
LIKELY TO RESULT IN DECENT COOLING AT NIGHT. FOLLOWED A BLEND OF MOS
GUIDANCE FOR LOWS.
TUESDAY NIGHT THROUGH SATURDAY...04.12Z ECMWF/GFS/CANADIAN AND ECMWF
ENSEMBLES SHOW THAT THE MORE ZONAL LOOKING NORTHERN STREAM WILL
BUCKLE DURING THE EXTENDED PORTION OF THE FORECAST. FOR FRIDAY AND
SATURDAY...GOOD AGREEMENT EXISTS IN FAIRLY DEEP TROUGHING OVER
CENTRAL CANADA...BEGINNING TO DROP DOWN TOWARDS THE FORECAST AREA.
IF THE 04.00Z/04.12Z ECMWF ARE CORRECT...WE COULD BE LOOKING AT A
SIGNIFICANT COOL DOWN HEADING INTO EARLY NEXT WEEK AS 850MB TEMPS
PLUMMET TO -8 TO -10C. BEFORE THAT TROUGH ARRIVES...THOUGH...A
SERIES OF WEAK COLD FRONTS / SYSTEMS ARE PROGGED TO COME THROUGH THE
AREA. THE FIRST MOVES THROUGH LATE WEDNESDAY. INSTABILITY BUILDING
AHEAD OF THIS FRONT...AIDED BY TEMPERATURES CLIMBING AT LEAST INTO
THE LOW IF NOT MID 70S...REQUIRES A CHANCE OF SHOWERS AND
THUNDERSTORMS. FOR THURSDAY INTO FRIDAY...THE 04.00Z/12Z ECMWF
INDICATES A SHORTWAVE TROUGH MOVING WEST TO EAST THROUGH THE
AREA...WHEREAS THE GFS AND CANADIAN KEEP THIS SHORTWAVE MUCH FARTHER
TO THE SOUTH. FOR NOW HAVE INCLUDED A CHANCE OF SHOWERS AND
THUNDERSTORMS UNTIL MODEL CONSISTENCY BECOMES BETTER. THEN FOR
SATURDAY WOULD BE THE STRONGER COLD FRONT ACCOMPANYING THE UPPER
TROUGH...THUS ANOTHER CHANCE OF PRECIPITATION. TEMPERATURES LOOK TO
STAY NEAR OR ABOVE NORMAL...UNTIL SATURDAY. SATURDAY COULD BE TRICKY
WITH HIGHS AS IT DEPENDS ON WHEN THE FRONT COMES THROUGH. 04.12Z
ECMWF IS SLOWER...WHICH WOULD SUGGEST THE BLEND OF ALL AVAILABLE
GUIDANCE MIGHT BE TOO COOL. WE WILL HAVE TO WAIT AND SEE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1240 PM CDT SAT MAY 4 2013
A COUPLE ITEMS TO LOOK AT THROUGH THE PERIOD. FIRST ITEM IS
SHRA/ISOLD T CHANCES GOING INTO THIS AFTERNOON/EARLY EVENING...AND
THE OTHER IS STRATUS/FOG DEVELOPMENT TONIGHT. CURRENT SURFACE
MAP/RADAR/VIS SATELLITE SHOWING LOW PRESSURE CENTERED OVER SW MO
WITH MOISTURE ROTATING AROUND IT INTO OUR AREA. MODELS DO DEVELOP
A SMALL AMOUNT OF INSTABILITY TO SUPPORT SOME SHOWERS/ISOLD T FOR
AREAS MAINLY ALONG/SOUTH OF I-94. CARRIED VCSH AT BOTH KRST/KLSE
FROM 20Z THROUGH 03Z. CIG/VIS EXPECTED TO BE VFR INTO EARLY THIS
EVENING...THEN RAPIDLY DETERIORATING INTO IFR/LIFR OVERNIGHT/EARLY
SUNDAY MORNING IN STRATUS/FOG AS THE VERY MOIST LOWER BOUNDARY
COOLS. LOOK FOR CONDITIONS TO SLOWLY IMPROVE AFTER 15Z SUNDAY.
&&
.HYDROLOGY...
ISSUED AT 306 PM CDT SAT MAY 4 2013
AFTER SOME ISOLATED/SCATTERED RAIN SHOWERS THROUGH THIS
EVENING...A FEW DAYS OF DRY WEATHER ARE EXPECTED. THESE DRY DAYS
WILL BE BENEFICIAL...ALLOWING RUNOFF FROM THE RECENT RAIN AND
SNOWMELT TO WORK ITS WAY THROUGH THE TRIBUTARIES INTO THE MAIN
STEM OF THE MISSISSIPPI RIVER. MOST OF THE TRIBUTARIES ARE
REMAINING BELOW FLOOD STAGE. MEANWHILE...ALL THE WATER EVENTUALLY
LOOKS TO PUSH SOME SITES ALONG THE MISSISSIPPI RIVER RIGHT TO
FLOOD STAGE. SEE THE LATEST FLOOD AND RIVER STATEMENTS FOR MORE
INFORMATION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY FROM 1 AM TO 10 AM CDT SUNDAY FOR WIZ032-033.
MN...DENSE FOG ADVISORY FROM 1 AM TO 10 AM CDT SUNDAY FOR MNZ079-
086>088-094-095.
IA...DENSE FOG ADVISORY FROM 1 AM TO 10 AM CDT SUNDAY FOR IAZ008-009-
018-019.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS
HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1240 PM CDT SAT MAY 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 256 AM CDT SAT MAY 4 2013
THE MAIN FOCUS FOR TODAY INTO TONIGHT IS WITH PRECIPITATION
CHANCES...THE POTENTIAL FOR DENSE FOG...AND HOW HIGH TEMPERATURES
WILL CLIMB TODAY.
A DEEPENING CUT OFF MID LEVEL LOW CONTINUES TO SLOWLY CHURN
EASTWARD ALONG THE MISSOURI/ARKANSAS BORDER AS A SURFACE LOW HAS
RETROGRADED TO THE WEST ACROSS CENTRAL ILLINOIS TOWARD THE
MISSOURI/IOWA BORDER. THIS HAS PULLED THE 925/850MB MOISTURE
TRANSPORT NORTHWEST INTO THE UPPER MISSISSIPPI VALLEY REGION WITH
SCATTERED CONVECTION DEVELOPING ALONG AND NORTH OF IT. AS THE
MID/LOW LEVEL LOW CONTINUES TO WRAP UP TODAY...THIS MOISTURE SURGE
SHOULD PUSH THE WEST WITH THE CONVECTION TRACKING THAT WAY AS
WELL EARLY THIS MORNING.
BEYOND THAT...AM NOT VERY CONFIDENT THAT THERE WILL BE MUCH IN THE
WAY OF CONVECTION ACROSS THE REGION WITH THE MAIN UPPER LEVEL
FORCING FROM THE LOW REMAINING TO THE SOUTH AND ANOTHER SHORT WAVE
STAYING WELL TO THE NORTH. THE MAIN FEATURE TO HELP TRIGGER ANY
SHOWERS/STORMS APPEARS TO BE WITH AN INVERTED SURFACE TROUGH THAT
IS CURRENTLY ALIGNED ALONG THE EASTERN SHORE OF LAKE MICHIGAN. THE
04.00Z NAM/GFS SHOW THIS FEATURE TRACKING WEST TODAY INTO
WISCONSIN AND SHOW SOME PRECIPITATION FORMING ALONG IT.
HOWEVER...THESE SAME MODELS BRING SURFACE DEW POINTS INTO THE LOW
60S AND DEVELOP A FEW HUNDRED J/KG OF SURFACE BASED CAPE IN AN
UNCAPPED ENVIRONMENT. MODIFYING THOSE SOUNDINGS TO HAVING DEW
POINTS IN THE LOW TO MID 50S YIELDS A CAPPED ENVIRONMENT WITH NO
SURFACE BASED CAPE. CURRENT DEW POINT ANALYSIS SHOWS THAT THE MAIN
SLUG OF HIGHER SURFACE DEW POINTS ARE CONFINED TO BEING JUST
EAST/NORTHEAST OF THE SURFACE LOW IN CENTRAL ILLINOIS WITH MID TO
UPPER 40S ELSEWHERE. WITH THIS SURFACE LOW DROPPING SOUTH
TODAY...EXPECT THAT THE BETTER CHANCES FOR CONVECTION WILL FOLLOW
IT AS WELL. SOME OF THE 04.00Z MESO-MODELS...SUCH AS THE NSSL
WRF...DO NOT CONVECT TODAY WHILE THE NMM AND THE 04.06Z HRRR DO
FORM SOME CONVECTION ALONG THE INSTABILITY AXIS WHERE THESE MODELS
FEATURE SURFACE DEW POINTS IN THE LOW 60S. BASED ON ALL
THIS...TRIED TO TREND PRECIPITATION CHANCES DOWN A BIT FOR TODAY.
TEMPERATURE-WISE FOR TODAY...FAIRLY HIGH BUST POTENTIAL BOTH WITH
POSSIBLY BEING TOO HIGH ON TEMPERATURES AND TOO LOW DEPENDING ON
THE LOCATION. LOW LEVEL EASTERLY WINDS WILL PULL A WARMER AIR
MASS INTO THE REGION TODAY...BUT HOW FAR WEST THIS AIR MAKES IT IS
THE MAIN QUESTION. HIGHS YESTERDAY IN LOWER MICHIGAN WERE IN THE
70S WHERE THIS AIR MASS WILL ORIGINATE FROM. HOW MUCH THE SNOW
PACK MELTS TODAY ACROSS SOUTHEAST MINNESOTA/NORTHEAST IOWA/NORTH
CENTRAL WISCONSIN WILL ALSO LIMIT TEMPERATURES A BIT THERE AS
WELL. DID NOT STRAY TOO FAR FROM GUIDANCE ON TEMPERATURES FOR
TODAY WITH HIGHER TEMPERATURES RANGING FROM THE UPPER 60S IN
EASTERN WISCONSIN TO THE UPPER 40S IN CENTRAL MINNESOTA.
WITH ALL OF THIS WARM AIR MOVING OVER A SNOW PACK AND OTHERWISE
MOIST SURFACES...EXPECT THAT THERE WILL BE FOG TONIGHT ACROSS MUCH
OF THE REGION. THE HIGHEST POTENTIAL FOR DENSE FOG WILL BE IN
THE AFOREMENTIONED SNOW PACK REGION WHERE A LOW LEVEL INVERSION
SHOULD TRAP MUCH OF THIS MOISTURE NEAR THE SURFACE.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 256 AM CDT SAT MAY 4 2013
FOR SUNDAY INTO MONDAY...THE MAIN QUESTION WILL BE WHETHER ANY
CONVECTION WILL CONTINUE TO DEVELOP ALONG THE STALLED OUT INVERTED
SURFACE TROUGH WHICH APPEARS TO SET UP ALONG THE MISSISSIPPI
RIVER. THE 04.00Z NAM/GFS WANT TO DEVELOP MORE PRECIPITATION ALONG
THIS FEATURE BUT STILL HAVE WAY TOO HIGH OF SURFACE DEW POINTS
ALONG IT AND SHOW TOO HIGH OF INSTABILITY WITH NO CAPPING AS A
RESULT. KEPT THE FORECAST DRY OVER THIS PERIOD...BUT WILL HAVE TO
WATCH FOR ANY TRENDS THERE IN THE SURFACE DEW POINTS.
OTHERWISE...THE CORE OF THE UPPER LEVEL LOW PROPAGATES TO THE
SOUTHEAST INTO THE MIDDLE OF NEXT WEEK WITH ANOTHER CUT OFF LOW
MEANDERING THROUGH THE ROCKIES. CONDITIONS SHOULD MAINLY BE DRY
INTO MID WEEK BEFORE THE TROUGH PUSHES BACK TO THE EAST.
PRECIPITATION CHANCES MAY BE A BIT OVERDONE FROM WEDNESDAY THROUGH
FRIDAY...BUT BOTH THE 04.00Z GFS AND ECMWF DEVELOP SHOWERS
THROUGHOUT THE PERIOD WITH THE LOW MOVING IN ALONG WITH A COLD
FRONT DROPPING DOWN FROM CANADA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1240 PM CDT SAT MAY 4 2013
A COUPLE ITEMS TO LOOK AT THROUGH THE PERIOD. FIRST ITEM IS
SHRA/ISOLD T CHANCES GOING INTO THIS AFTERNOON/EARLY EVENING...AND THE
OTHER IS STRATUS/FOG DEVELOPMENT TONIGHT. CURRENT SURFACE
MAP/RADAR/VIS SATELLITE SHOWING LOW PRESSURE CENTERED OVER SW MO
WITH MOISTURE ROTATING AROUND IT INTO OUR AREA. MODELS DO DEVELOP
A SMALL AMOUNT OF INSTABILITY TO SUPPORT SOME SHOWERS/ISOLD T FOR
AREAS MAINLY ALONG/SOUTH OF I-94. CARRIED VCSH AT BOTH KRST/KLSE
FROM 20Z THROUGH 03Z. CIG/VIS EXPECTED TO BE VFR INTO EARLY THIS
EVENING...THEN RAPIDLY DETERIORATING INTO IFR/LIFR OVERNIGHT/EARLY
SUNDAY MORNING IN STRATUS/FOG AS THE VERY MOIST LOWER BOUNDARY
COOLS. LOOK FOR CONDITIONS TO SLOWLY IMPROVE AFTER 15Z SUNDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
654 AM CDT SAT MAY 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 256 AM CDT SAT MAY 4 2013
THE MAIN FOCUS FOR TODAY INTO TONIGHT IS WITH PRECIPITATION
CHANCES...THE POTENTIAL FOR DENSE FOG...AND HOW HIGH TEMPERATURES
WILL CLIMB TODAY.
A DEEPENING CUT OFF MID LEVEL LOW CONTINUES TO SLOWLY CHURN
EASTWARD ALONG THE MISSOURI/ARKANSAS BORDER AS A SURFACE LOW HAS
RETROGRADED TO THE WEST ACROSS CENTRAL ILLINOIS TOWARD THE
MISSOURI/IOWA BORDER. THIS HAS PULLED THE 925/850MB MOISTURE
TRANSPORT NORTHWEST INTO THE UPPER MISSISSIPPI VALLEY REGION WITH
SCATTERED CONVECTION DEVELOPING ALONG AND NORTH OF IT. AS THE
MID/LOW LEVEL LOW CONTINUES TO WRAP UP TODAY...THIS MOISTURE SURGE
SHOULD PUSH THE WEST WITH THE CONVECTION TRACKING THAT WAY AS
WELL EARLY THIS MORNING.
BEYOND THAT...AM NOT VERY CONFIDENT THAT THERE WILL BE MUCH IN THE
WAY OF CONVECTION ACROSS THE REGION WITH THE MAIN UPPER LEVEL
FORCING FROM THE LOW REMAINING TO THE SOUTH AND ANOTHER SHORT WAVE
STAYING WELL TO THE NORTH. THE MAIN FEATURE TO HELP TRIGGER ANY
SHOWERS/STORMS APPEARS TO BE WITH AN INVERTED SURFACE TROUGH THAT
IS CURRENTLY ALIGNED ALONG THE EASTERN SHORE OF LAKE MICHIGAN. THE
04.00Z NAM/GFS SHOW THIS FEATURE TRACKING WEST TODAY INTO
WISCONSIN AND SHOW SOME PRECIPITATION FORMING ALONG IT.
HOWEVER...THESE SAME MODELS BRING SURFACE DEW POINTS INTO THE LOW
60S AND DEVELOP A FEW HUNDRED J/KG OF SURFACE BASED CAPE IN AN
UNCAPPED ENVIRONMENT. MODIFYING THOSE SOUNDINGS TO HAVING DEW
POINTS IN THE LOW TO MID 50S YIELDS A CAPPED ENVIRONMENT WITH NO
SURFACE BASED CAPE. CURRENT DEW POINT ANALYSIS SHOWS THAT THE MAIN
SLUG OF HIGHER SURFACE DEW POINTS ARE CONFINED TO BEING JUST
EAST/NORTHEAST OF THE SURFACE LOW IN CENTRAL ILLINOIS WITH MID TO
UPPER 40S ELSEWHERE. WITH THIS SURFACE LOW DROPPING SOUTH
TODAY...EXPECT THAT THE BETTER CHANCES FOR CONVECTION WILL FOLLOW
IT AS WELL. SOME OF THE 04.00Z MESO-MODELS...SUCH AS THE NSSL
WRF...DO NOT CONVECT TODAY WHILE THE NMM AND THE 04.06Z HRRR DO
FORM SOME CONVECTION ALONG THE INSTABILITY AXIS WHERE THESE MODELS
FEATURE SURFACE DEW POINTS IN THE LOW 60S. BASED ON ALL
THIS...TRIED TO TREND PRECIPITATION CHANCES DOWN A BIT FOR TODAY.
TEMPERATURE-WISE FOR TODAY...FAIRLY HIGH BUST POTENTIAL BOTH WITH
POSSIBLY BEING TOO HIGH ON TEMPERATURES AND TOO LOW DEPENDING ON
THE LOCATION. LOW LEVEL EASTERLY WINDS WILL PULL A WARMER AIR
MASS INTO THE REGION TODAY...BUT HOW FAR WEST THIS AIR MAKES IT IS
THE MAIN QUESTION. HIGHS YESTERDAY IN LOWER MICHIGAN WERE IN THE
70S WHERE THIS AIR MASS WILL ORIGINATE FROM. HOW MUCH THE SNOW
PACK MELTS TODAY ACROSS SOUTHEAST MINNESOTA/NORTHEAST IOWA/NORTH
CENTRAL WISCONSIN WILL ALSO LIMIT TEMPERATURES A BIT THERE AS
WELL. DID NOT STRAY TOO FAR FROM GUIDANCE ON TEMPERATURES FOR
TODAY WITH HIGHER TEMPERATURES RANGING FROM THE UPPER 60S IN
EASTERN WISCONSIN TO THE UPPER 40S IN CENTRAL MINNESOTA.
WITH ALL OF THIS WARM AIR MOVING OVER A SNOW PACK AND OTHERWISE
MOIST SURFACES...EXPECT THAT THERE WILL BE FOG TONIGHT ACROSS MUCH
OF THE REGION. THE HIGHEST POTENTIAL FOR DENSE FOG WILL BE IN
THE AFOREMENTIONED SNOW PACK REGION WHERE A LOW LEVEL INVERSION
SHOULD TRAP MUCH OF THIS MOISTURE NEAR THE SURFACE.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 256 AM CDT SAT MAY 4 2013
FOR SUNDAY INTO MONDAY...THE MAIN QUESTION WILL BE WHETHER ANY
CONVECTION WILL CONTINUE TO DEVELOP ALONG THE STALLED OUT INVERTED
SURFACE TROUGH WHICH APPEARS TO SET UP ALONG THE MISSISSIPPI
RIVER. THE 04.00Z NAM/GFS WANT TO DEVELOP MORE PRECIPITATION ALONG
THIS FEATURE BUT STILL HAVE WAY TOO HIGH OF SURFACE DEW POINTS
ALONG IT AND SHOW TOO HIGH OF INSTABILITY WITH NO CAPPING AS A
RESULT. KEPT THE FORECAST DRY OVER THIS PERIOD...BUT WILL HAVE TO
WATCH FOR ANY TRENDS THERE IN THE SURFACE DEW POINTS.
OTHERWISE...THE CORE OF THE UPPER LEVEL LOW PROPAGATES TO THE
SOUTHEAST INTO THE MIDDLE OF NEXT WEEK WITH ANOTHER CUT OFF LOW
MEANDERING THROUGH THE ROCKIES. CONDITIONS SHOULD MAINLY BE DRY
INTO MID WEEK BEFORE THE TROUGH PUSHES BACK TO THE EAST.
PRECIPITATION CHANCES MAY BE A BIT OVERDONE FROM WEDNESDAY THROUGH
FRIDAY...BUT BOTH THE 04.00Z GFS AND ECMWF DEVELOP SHOWERS
THROUGHOUT THE PERIOD WITH THE LOW MOVING IN ALONG WITH A COLD
FRONT DROPPING DOWN FROM CANADA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 654 AM CDT SAT MAY 4 2013
BUFKIT SOUNDINGS SHOW THAT THE LIFR/IFR DECK WILL GRADUALLY
BECOME MVFR BY EARLY THIS AFTERNOON. WITH THE DRY AIR JUST OF THE
EAST...KEPT THE IDEA THAT KLSE MAY EVEN BECOME VFR FOR THIS
AFTERNOON AND EVENING. WITH MANY OF THE SHOWERS EXITING THE AREA
AND THE MESO MODELS NOT SHOWING JUST SCATTERED SHOWERS THIS
AFTERNOON AND EVENING...KEPT THE PRECIPITATION OUT OF BOTH TAF
SITES.
FOR LATE TONIGHT...THE MAIN QUESTION IS WHETHER DENSE FOG WILL
DEVELOP. WITH LIGHT SURFACE WINDS AND SNOW MELT ACROSS SOUTHEAST
MINNESOTA AND NORTHEAST IOWA...THERE IS A CONCERN THAT DENSE FOG
MAY DEVELOP. HOWEVER WITH THE WINDS ABOVE THE SURFACE AROUND
10 KNOTS AND THE POTENTIAL THAT SOME OF MOISTURE COULD GET INTO
THE SOIL...IT IS NOT A GIVEN. AS A RESULT...JUST LOWERED THE CEILINGS
AND ADDED SOME FOG TO THE FORECAST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
256 AM CDT SAT MAY 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 256 AM CDT SAT MAY 4 2013
THE MAIN FOCUS FOR TODAY INTO TONIGHT IS WITH PRECIPITATION
CHANCES...THE POTENTIAL FOR DENSE FOG...AND HOW HIGH TEMPERATURES
WILL CLIMB TODAY.
A DEEPENING CUT OFF MID LEVEL LOW CONTINUES TO SLOWLY CHURN
EASTWARD ALONG THE MISSOURI/ARKANSAS BORDER AS A SURFACE LOW HAS
RETROGRADED TO THE WEST ACROSS CENTRAL ILLINOIS TOWARD THE
MISSOURI/IOWA BORDER. THIS HAS PULLED THE 925/850MB MOISTURE
TRANSPORT NORTHWEST INTO THE UPPER MISSISSIPPI VALLEY REGION WITH
SCATTERED CONVECTION DEVELOPING ALONG AND NORTH OF IT. AS THE
MID/LOW LEVEL LOW CONTINUES TO WRAP UP TODAY...THIS MOISTURE SURGE
SHOULD PUSH THE WEST WITH THE CONVECTION TRACKING THAT WAY AS
WELL EARLY THIS MORNING.
BEYOND THAT...AM NOT VERY CONFIDENT THAT THERE WILL BE MUCH IN THE
WAY OF CONVECTION ACROSS THE REGION WITH THE MAIN UPPER LEVEL
FORCING FROM THE LOW REMAINING TO THE SOUTH AND ANOTHER SHORT WAVE
STAYING WELL TO THE NORTH. THE MAIN FEATURE TO HELP TRIGGER ANY
SHOWERS/STORMS APPEARS TO BE WITH AN INVERTED SURFACE TROUGH THAT
IS CURRENTLY ALIGNED ALONG THE EASTERN SHORE OF LAKE MICHIGAN. THE
04.00Z NAM/GFS SHOW THIS FEATURE TRACKING WEST TODAY INTO
WISCONSIN AND SHOW SOME PRECIPITATION FORMING ALONG IT.
HOWEVER...THESE SAME MODELS BRING SURFACE DEW POINTS INTO THE LOW
60S AND DEVELOP A FEW HUNDRED J/KG OF SURFACE BASED CAPE IN AN
UNCAPPED ENVIRONMENT. MODIFYING THOSE SOUNDINGS TO HAVING DEW
POINTS IN THE LOW TO MID 50S YIELDS A CAPPED ENVIRONMENT WITH NO
SURFACE BASED CAPE. CURRENT DEW POINT ANALYSIS SHOWS THAT THE MAIN
SLUG OF HIGHER SURFACE DEW POINTS ARE CONFINED TO BEING JUST
EAST/NORTHEAST OF THE SURFACE LOW IN CENTRAL ILLINOIS WITH MID TO
UPPER 40S ELSEWHERE. WITH THIS SURFACE LOW DROPPING SOUTH
TODAY...EXPECT THAT THE BETTER CHANCES FOR CONVECTION WILL FOLLOW
IT AS WELL. SOME OF THE 04.00Z MESO-MODELS...SUCH AS THE NSSL
WRF...DO NOT CONVECT TODAY WHILE THE NMM AND THE 04.06Z HRRR DO
FORM SOME CONVECTION ALONG THE INSTABILITY AXIS WHERE THESE MODELS
FEATURE SURFACE DEW POINTS IN THE LOW 60S. BASED ON ALL
THIS...TRIED TO TREND PRECIPITATION CHANCES DOWN A BIT FOR TODAY.
TEMPERATURE-WISE FOR TODAY...FAIRLY HIGH BUST POTENTIAL BOTH WITH
POSSIBLY BEING TOO HIGH ON TEMPERATURES AND TOO LOW DEPENDING ON
THE LOCATION. LOW LEVEL EASTERLY WINDS WILL PULL A WARMER AIR
MASS INTO THE REGION TODAY...BUT HOW FAR WEST THIS AIR MAKES IT IS
THE MAIN QUESTION. HIGHS YESTERDAY IN LOWER MICHIGAN WERE IN THE
70S WHERE THIS AIR MASS WILL ORIGINATE FROM. HOW MUCH THE SNOW
PACK MELTS TODAY ACROSS SOUTHEAST MINNESOTA/NORTHEAST IOWA/NORTH
CENTRAL WISCONSIN WILL ALSO LIMIT TEMPERATURES A BIT THERE AS
WELL. DID NOT STRAY TOO FAR FROM GUIDANCE ON TEMPERATURES FOR
TODAY WITH HIGHER TEMPERATURES RANGING FROM THE UPPER 60S IN
EASTERN WISCONSIN TO THE UPPER 40S IN CENTRAL MINNESOTA.
WITH ALL OF THIS WARM AIR MOVING OVER A SNOW PACK AND OTHERWISE
MOIST SURFACES...EXPECT THAT THERE WILL BE FOG TONIGHT ACROSS MUCH
OF THE REGION. THE HIGHEST POTENTIAL FOR DENSE FOG WILL BE IN
THE AFOREMENTIONED SNOW PACK REGION WHERE A LOW LEVEL INVERSION
SHOULD TRAP MUCH OF THIS MOISTURE NEAR THE SURFACE.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 256 AM CDT SAT MAY 4 2013
FOR SUNDAY INTO MONDAY...THE MAIN QUESTION WILL BE WHETHER ANY
CONVECTION WILL CONTINUE TO DEVELOP ALONG THE STALLED OUT INVERTED
SURFACE TROUGH WHICH APPEARS TO SET UP ALONG THE MISSISSIPPI
RIVER. THE 04.00Z NAM/GFS WANT TO DEVELOP MORE PRECIPITATION ALONG
THIS FEATURE BUT STILL HAVE WAY TOO HIGH OF SURFACE DEW POINTS
ALONG IT AND SHOW TOO HIGH OF INSTABILITY WITH NO CAPPING AS A
RESULT. KEPT THE FORECAST DRY OVER THIS PERIOD...BUT WILL HAVE TO
WATCH FOR ANY TRENDS THERE IN THE SURFACE DEW POINTS.
OTHERWISE...THE CORE OF THE UPPER LEVEL LOW PROPAGATES TO THE
SOUTHEAST INTO THE MIDDLE OF NEXT WEEK WITH ANOTHER CUT OFF LOW
MEANDERING THROUGH THE ROCKIES. CONDITIONS SHOULD MAINLY BE DRY
INTO MID WEEK BEFORE THE TROUGH PUSHES BACK TO THE EAST.
PRECIPITATION CHANCES MAY BE A BIT OVERDONE FROM WEDNESDAY THROUGH
FRIDAY...BUT BOTH THE 04.00Z GFS AND ECMWF DEVELOP SHOWERS
THROUGHOUT THE PERIOD WITH THE LOW MOVING IN ALONG WITH A COLD
FRONT DROPPING DOWN FROM CANADA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1106 PM CDT FRI MAY 3 2013
NUMEROUS SHOWERS CONTINUE TO STREAM NORTHWARD INTO THE TAF SITES...
THOUGH THEY ARE BECOMING MORE ISOLATED AROUND KLSE. THIS IS DUE TO
SOME DRIER AIR ALOFT TRYING TO WORK WESTWARD OUT OF LOWER
MICHIGAN. ALONG WITH THE DRIER AIR ALOFT IS WARMER AIR...WHICH IS
TRAPPING THE COOL...MOIST AIR AT THE SURFACE. AS A RESULT...LIFR
CEILINGS PERSIST AT KRST AND IFR/MVFR CEILINGS AT KLSE.
ANTICIPATING CEILINGS TO REMAIN STATUS QUO UNTIL LATE THIS MORNING
AND EARLY THIS AFTERNOON...WHICH IS WHEN THEY SHOULD BEGIN RISING
IN RESPONSE TO DAYTIME MIXING. THE BEST IMPROVEMENT IS EXPECTED AT
KLSE...CLOSER TO THE WARMER AND DRIER AIR COMING OUT OF LOWER
MICHIGAN. IN FACT...KLSE MAY EVEN GO VFR AT 23Z. HEADING INTO THE
EVENING HOURS...DIMINISHING WINDS AND NIGHTTIME COOLING RAISES
CONCERNS ABOUT FOG AND LOW STRATUS FORMATION...ESPECIALLY AT KRST
WITH MELTING SNOW. INCLUDED MVFR VISIBILITIES AT A MINIMUM FROM
BR...AND THESE COULD EASILY GO LOWER AFTER 06Z. WITH UNCERTAINTY
AT KRST OF THE LOW STRATUS NEVER BREAKING UP DURING THE
AFTERNOON...A GREATER CHANCE EXISTS THERE OF CEILINGS DROPPING
BACK DOWN TO IFR IN THE EVENING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS TUCSON AZ
915 PM MST SUN MAY 5 2013
.SYNOPSIS...SHOWERS WILL SPREAD INTO THE AREA LATER TONIGHT INTO
EARLY MONDAY MORNING. PERIODS OF CLOUDS THROUGHOUT MUCH OF THE WEEK
AS LOW PRESSURE SETTLES IN OVER SOUTHERN ARIZONA. TEMPERATURES
RUNNING ABOUT SIX TO TEN DEGREES COOLER THAN AVERAGE. A FEW SHOWERS
POSSIBLE LATER IN THE WEEK AS WELL.
&&
.DISCUSSION...LIGHT SHOWERS SPREADING IN FROM THE SOUTHWEST WITH
EMBEDDED MODERATE SHOWER ACTIVITY AND EVEN A COUPLE OF
LIGHTNING STRIKES STILL WELL SOUTHWEST OF THE BORDER. TIA DEWPOINT
HOPPED INTO THE UPPER 30S IN THE PAST 30 MINUTES WITH 30S COMMON NOW
THROUGH SE AZ. SATELLITE SOUNDER PRECIPITABLE WATER ESTIMATES HAVE
US AROUND THE .5 TO .6 RANGE WITH .75 TO .85 VALUES JUST SOUTHWEST
OF US. STILL EXPECTING THE BEST DYNAMICS AND MOISTURE COUPLET (SUCH
AS IT IS) BETWEEN 06Z AND 09Z.
LARGE SCALE BLOCKING FEATURES IMMEDIATELY UPSTREAM AND DOWNSTREAM
WILL KEEP A WEAK MEAN TROUGH POSITION THROUGH THE AREA THIS WEEK. A
FEW LIGHT SHOWERS WITH PERIODS OF CLOUDINESS. TEMPERATURES TO RUN UP
TO 10 DEGREES BELOW CLIMO MOST OF THE WEEK. GRADIENT ENHANCEMENT TO
WINDS THROUGH WEDNESDAY OR SO.
A STRONGER BIT OF REINFORCING ENERGY COULD BRING MORE ORGANIZED
SHOWERS TO THE AREA AROUND THURSDAY NIGHT OR FRIDAY.
&&
.PREV DISCUSSION...00Z KTWC SOUNDING CREPT BACK JUST ABOVE 1/2 INCH
PRECIPITABLE WATER FOR THE FIRST TIME IN A FEW WEEKS. HIGHER VALUES
LINING UP TO PUSH THIS WAY TONIGHT FROM THE SOUTH AND SOUTHWEST ON
BLENDED TOTAL PRECIPITABLE WATER IMAGERY. LATEST NAMDNG5 AND RAPID
REFRESH TRENDS CONTINUE TO ROTATE THE IMPULSE CURRENTLY NEAR THE
NORTHERN BAJA PENINSULA QUICKLY UNDER AND UP AHEAD OF THE
CONSOLIDATING LOW POSITION...THEN THROUGH SOUTHEAST ARIZONA AFTER
06Z. WE EARLIER ADJUSTED POP AND QPF TRENDS UP...WHILE NARROWING THE
WINDOW FOR THE MAIN FOCUS OF PRECIP CHANCES PRIMARILY BETWEEN
06Z-12Z FOR MOST OF SE AZ. HRRR CAPE IS ELEVATED TO A COUPLE OF
POCKETS ABOVE 500J AS THIS FEATURE PUSHES THROUGH SO A LIGHTNING
STRIKE OR TWO IS NOT OUT OF THE QUESTION.
&&
.AVIATION...MID CLOUDS THICKENING AND LOWERING FROM WEST TO
EAST...WITH SCT-BKN CLOUDS AT 7-10K FT AGL BETWEEN 06/04Z AND
06/16Z. CHC -SHRA/-TSRA BETWEEN 06/06Z AND 06/15Z. SLY/SWLY SURFACE
WIND AT 10-15 KTS WITH GUSTS TO 25 KTS TIL 06/06Z. AFT
06/06Z...SURFACE WIND DIMINISHING...AND MAINLY LESS THAN 10 KTS BY
06/12Z. SWLY SURFACE WIND INCREASING AGAIN AFT 06/17Z TO 12-17 KTS
AND HIGHER GUSTS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...COOLER TEMPERATURES ARE EXPECTED THROUGH THE END OF
THE UPCOMING WORK WEEK. THERE WILL BE A CHANCE OF SHOWERS TONIGHT
INTO MONDAY...ALONG WITH A POSSIBLE LIGHTNING STRIKE OR TWO. BREEZY
WINDS ARE ALSO EXPECTED THROUGH AT LEAST TUESDAY. WITH THE COOLER
TEMPERATURES AND CORRESPONDING INCREASES IN RELATIVE HUMIDITY
VALUES...CONDITIONS ARE EXPECTED TO REMAIN BELOW CRITICAL FIRE
WEATHER THRESHOLDS...EVEN THOUGH WINDS WILL BE STRONG AT TIMES
DURING THE AFTERNOON AND EARLY EVENING HOURS.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
MEYER/LADER
AVIATION/FIRE WEATHER...ZELL
AREA FORECAST DISCUSSION
NWS TOPEKA KS
339 AM CDT MON MAY 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 339 AM CDT MON MAY 6 2013
11-3.9 MICRON MICROWAVE IMAGERY INDICATES A STRATUS LAYER STRETCHING
FROM NORTH TO SOUTH ACROSS EASTERN NEBRASKA...EASTERN
KANSAS...WESTERN IOWA...AND WESTERN MISSOURI. THE GENERAL THOUGHT IS
THAT THE STRATUS WILL RESIDE ALONG AND EAST OF A SURFACE RIDGE
AXIS...WHICH IS CURRENTLY SITUATED IN E NEB AND E KANSAS. AS THIS
SURFACE RIDGE SCOOTS EASTWARD EXPECT THE STRATUS TO MOVE OUT WITH
IT. CLOUDS MAY ALSO BREAK UP LATER TODAY AS LOW LEVEL MIXING
COMMENCES AFTER SUNRISE. DAYTIME HIGHS TODAY ARE SOMEWHAT DEPENDENT
ON HOW THE STRATUS BEHAVES. LEANED MORE IN THE DIRECTION OF EARLY
STRATUS DISSIPATION AS THE SATURATED LAYER RESPONSIBLE FOR THE CLOUD
COVER IS RATHER THIN. OVERNIGHT TONIGHT STRONG WARM AIR ADVECTION
AHEAD OF A DEEPENING LEE SIDE SURFACE TROUGH WILL KICK UP A FEW
SHOWERS AND THUNDERSTORMS ACROSS WESTERN/CENTRAL KANSAS...SOME OF
WHICH MAY SPILL INTO THE FAR WESTERN ZONES EARLY TUESDAY
MORNING...ALTHOUGH THE BULK OF THE ACTIVITY LOOKS TO REMAIN WELL
WEST OF THE FORECAST AREA THROUGH THE OVERNIGHT HOURS MONDAY NIGHT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 339 AM CDT MON MAY 6 2013
FOR TUESDAY THROUGH FRIDAY...MODELS CONTINUE TO SHOW A
CONDITIONALLY UNSTABLE ATMOSPHERE WITH WEAK PERTURBATIONS
POTENTIALLY MOVING THROUGH THE WEAK FLOW ALOFT. WEDNESDAY NIGHT
AND THURSDAY CONTINUE TO LOOK LIKE THE TIME WHEN PRECIP IS MOST
LIKELY AS THE CLOSED LOW CURRENTLY ON THE WEST COAST MOVES OUT
FROM THE ROCKIES AND BRING AN INVERTED TROUGH AXIS INTO THE
FORECAST AREA. FORCING FROM THE UPPER LOW AND LOW LEVEL
CONVERGENCES ALONG THE SURFACE TROUGH LOOK TO PRODUCE CONDITIONS
LIKELY FOR PRECIP. OTHERWISE PRECIP CAN NOT BE RULED OUT FOR ANY
DAY SINCE MODELS SHOW LITTLE INHIBITION TO CONVECTION AND THE
POTENTIAL FOR WEAK DISTURBANCES TO SPARK SOMETHING. HAVE NOT MADE
MANY CHANGES FROM THE PREV FORECAST WITH POPS THROUGHOUT THE
PERIOD AND MILD TEMPS WITH LOWS IN THE 50S AND HIGHS IN THE 70S.
BY FRIDAY...THE MEDIUM RANGE MODELS BEGIN TO AMPLIFY AN UPPER
LEVEL RIDGE ALONG THE WEST COAST. THIS SHOULD ALLOW FOR NORTHERN
STREAM ENERGY TO DIG SOUTH AND FOR A MID LEVEL TROUGH OVER THE
GREAT LAKES AND NORTHWEST FLOW ACROSS THE NORTHERN AND CENTRAL
PLAINS. THERE IS PRETTY GOOD AGREEMENT WITH THE MODELS THAT THIS
AMPLIFICATION OF THE PATTERN WILL BRING A COLD FRONT THROUGH THE
AREA SATURDAY WITH RIDGING BUILDING IN FOR SATURDAY NIGHT AND
SUNDAY. SO HAVE SOME SMALL POPS IN FOR SATURDAY FOR THE FRONTAL
PASSAGE WITH A DRY FORECAST SATURDAY NIGHT AND SUNDAY. TRENDED
TEMPS DOWN FOR SATURDAY AND SUNDAY SINCE IT APPEARS THE AIRMASS
BEHIND THE COLD FRONT SHOULD ORIGINATE FROM CANADA...WITH LOWS IN
THE 40S AND HIGHS IN THE 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1151 PM CDT SUN MAY 5 2013
CONFIDENCE REMAINS LOW. SATELLITE DATA INDICATES TRANSIENT HOLES
IN STRATUS...AS WELL AS SOME CLEARING OCCURRING ITS WESTERN EDGE.
HEIGHTS GENERALLY LOWERING WITH TIME...THOUGH KTOP RECENTLY
RAISED. MODELS GIVING LITTLE HELP...THOUGH RAP SEEMS THE CLOSEST
WITH REALITY AND FOLLOWED IT THE CLOSEST. CLOUD-LEVEL WINDS APPEAR
TO VEER AND WOULD PUSH STRATUS BACK WEST. SLOW DIURNAL COOLING
SHOULD BRING AT LEAST KFOE TO IFR...THOUGH POSSIBLY ON THE IFR
EDGE AT KTOP. SLOW IMPROVEMENTS SHOULD OCCUR BY 18Z.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...LEIGHTON
LONG TERM...WOLTERS
AVIATION...65
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1151 PM CDT SUN MAY 5 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 340 PM CDT SUN MAY 5 2013
THE UPPER LEVEL LOW ALONG WITH THE SURFACE LOW WAS MOVING EASTWARD
ACROSS NORTHERN MS LATE THIS AFTERNOON. THE LOW-LEVEL MOISTURE
CONTINUED TO BROADLY WRAP AROUND THIS VERTICALLY STACKED SYSTEM WITH
THE TRAJECTORY OF MOISTURE WRAPPING NORTHWESTWARD FROM THE OH RIVER
VALLEY INTO EASTERN IA...WHERE THE MOISTURE TRAJECTORIES EXTENDED
SOUTHWEST AND SOUTH INTO NORTHERN MO AND EXTREME EASTERN KS. AS A
RESULT THE LOW STRATUS HAS STAYED IN PLACE ACROSS MOST OF THE CWA
INTO THE AFTERNOON HOURS. THE SKIES HAVE JUST BEGUN TO CLEAR ACROSS
NORTH CENTRAL KS WHERE TEMPERATURES HAVE WARMED UP TO NEAR 60. UNDER
THE CLOUDS ACROSS THE EASTERN TWO THIRDS OF THE CWA...TEMPERATURES
HAVE ONLY SLOWLY WARMED INTO THE UPPER 40S AND LOWER 50S. THE HIGHS
TODAY ACROSS THE EASTERN HALF OF THE CWA WILL PROBABLY OCCUR AROUND
600 PM WHEN SKIES MAY BEGIN TO CLEAR.
AS THE UPPER LEVEL LOW CONTINUES TO MOVE EAST
INTO AL...THE CLEARING TREND SHOULD GRADUALLY PUSH EASTWARD ACROSS
THE CWA DURING THE LATE AFTERNOON AND EARLY EVENING HOURS. MOST
AREAS SHOULD CLEAR OUT BY 9PM. HIGH CLOUDS WERE ROTATING AROUND AN
H5 RIDGE ACROSS THE DESERT SOUTHWEST...AND MAY MOVE BACK INTO THE
CWA DURING THE EARLY MORNING HOURS OF MONDAY. MOSTLY CLEAR SKIES
TONIGHT ALONG WITH LIGHT WINDS WILL ALLOW AREAS OF GROUND FOG TO
DEVELOP LATE TONIGHT. HOWEVER...IF THE HIGH CLOUDS ARE THICKER THEN
THE GROUND FOG MAY BE QUITE PATCHY AND MAY ONLY FORM IN LOW-LYING
AREAS...ALONG LAKES AND WITHIN RIVER VALLEYS. LOWS WILL ONLY DROP
INTO THE LOWER TO MID 40S.
MONDAY...ANY PATCHY FOG THAT FORMS BEFORE SUNRISE WILL QUICKLY MIX
OUT BY 14Z. A SOUTHERN STREAM H5 RIDGE WILL MOVE EAST INTO THE
SOUTHERN PLAINS BY AFTERNOON. SKIES WILL BE MOSTLY TO PARTLY SUNNY.
THIS WILL ALLOW HIGHS TO WARM INTO THE UPPER 60S TO LOWER 70S. NORTH
WINDS WILL BECOME LIGHT AND VARIABLE THROUGH THE AFTERNOON HOURS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 340 PM CDT SUN MAY 5 2013
A WEAK UPPER LEVEL RIDGE WILL BE IN PLACE OVER THE CENTRAL AND
SOUTHERN PLAINS MONDAY NIGHT WITH THE EXITING UPPER LEVEL LOW
PROGRESSING EASTWARD TOWARD THE SOUTHEASTERN U.S AND A SECOND UPPER
LOW MOVING ONSHORE INTO THE SOUTHWESTERN U.S. MODELS CONTINUE TO
SHOW A SHORTWAVE DEVELOPING ALONG THE NORTHERN EDGE OF THE
RIDGE...BRINGING THE CHANCE FOR SOME SCATTERED SHOWERS AND
THUNDERSTORMS TO THE AREA TUESDAY INTO WEDNESDAY.
OTHERWISE... THE MAIN FOCUS IS ON THE SECOND UPPER LEVEL LOW AS IT
PROGRESSES EASTWARD TOWARD THE CENTRAL PLAINS. WHILE THE MODELS ARE
BEGINNING TO COME INTO BETTER AGREEMENT WITH THE SYNOPTIC SCALE
TRENDS...THERE ARE STILL SOME DISCREPANCIES IN THE DETAILS OF THE
BEST TIMING AND LOCATION FOR PRECIPITATION ACROSS THE FORECAST AREA
THROUGH THE END OF THE WEEK. AS A RESULT...CONTINUE TO HAVE THE
MENTION OF POPS FOR MUCH OF THE CWA THROUGH SATURDAY. 12Z MODEL RUNS
ARE SHOWING THE UPPER LOW MOVING INTO THE FOUR CORNERS REGION BY
WEDNESDAY AND WEAKENING TO THE POINT THAT A WEAK POSITIVELY-TILTED
TROUGH BEGINS TO FORM OVER THE ROCKIES AND CENTRAL CONUS BY THE END
OF THE WEEK. THE SURFACE LOW ASSOCIATED WITH THIS SYSTEM WILL SLOWLY
PROGRESS EASTWARD INTO THE CENTRAL PLAINS...WITH MODELS IN FAIRLY
GOOD AGREEMENT IN HAVING THE LOW TRACK JUST SOUTH OF THE FORECAST
AREA BY THE END OF THE WEEK AND INTO SATURDAY. AT THIS TIME...THE
BETTER CHANCES FOR PRECIPITATION LOOK TO BE WEDNESDAY NIGHT THROUGH
THURSDAY AS A FRONTAL BOUNDARY MAY TRACK SOUTHWARD THROUGH THE CWA.
AN UPPER LEVEL RIDGE LOOKS TO DEVELOP ALONG THE PACIFIC COASTLINE BY
FRIDAY AND SLOWLY MOVE EASTWARD...HELPING TO PUSH THE GRADUALLY
DEEPENING UPPER LEVEL TROUGH EAST OF THE AREA BY THE LATTER PART OF
THE WEEKEND. THUNDERSTORM POTENTIAL LOOKS TO DIMINISH TOWARDS THE END
OF THE WEEK INTO THE WEEKEND AS INSTABILITY WEAKENS OVER THE AREA
WITH THE EXITING SYSTEM. WHILE THERE IS STILL UNCERTAINTY WITH HOW
QUICKLY THIS SYSTEM WILL EXIT THE AREA...HAVE CONTINUED TO TREND
DOWNWARD WITH POPS FRIDAY NIGHT INTO SATURDAY WITH DRY CONDITIONS
SATURDAY NIGHT AND SUNDAY. AS FOR TEMPERATURES...HIGHS MID TO LATE
WEEK LOOK TO BE NEAR THE SEASONAL NORMALS IN THE LOWER TO MIDDLE 70S
WITH SLIGHTLY COOLER CONDITIONS BY THE WEEKEND AS HIGHS DROP INTO THE
MID/UPPER 60S. LOW TEMPERATURES LOOK TO BE IN THE 50S THROUGH THE
END OF THE WEEK AND COOLING INTO THE 40S BY THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1151 PM CDT SUN MAY 5 2013
CONFIDENCE REMAINS LOW. SATELLITE DATA INDICATES TRANSIENT HOLES
IN STRATUS...AS WELL AS SOME CLEARING OCCURRING ITS WESTERN EDGE.
HEIGHTS GENERALLY LOWERING WITH TIME...THOUGH KTOP RECENTLY
RAISED. MODELS GIVING LITTLE HELP...THOUGH RAP SEEMS THE CLOSEST
WITH REALITY AND FOLLOWED IT THE CLOSEST. CLOUD-LEVEL WINDS APPEAR
TO VEER AND WOULD PUSH STRATUS BACK WEST. SLOW DIURNAL COOLING
SHOULD BRING AT LEAST KFOE TO IFR...THOUGH POSSIBLY ON THE IFR
EDGE AT KTOP. SLOW IMPROVEMENTS SHOULD OCCUR BY 18Z.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GARGAN
LONG TERM...HENNECKE
AVIATION...65
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
356 AM EDT MON MAY 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM EDT MON MAY 6 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG STRETCHING
FM THE NE CONUS W INTO THE UPR GRT LKS TO THE N OF CUTOFF LO OVER
THE SE CONUS. VERY DRY AIRMASS SHOWN ON THE 00Z GRB/APX RAOBS...
WHICH SHOW A PWAT ARND 0.25 INCH OR 50 PCT OF NORMAL...DOMINATES THE
CWA. SO SKIES ARE MOCLR EXCEPT FOR SOME HI CLDS. SFC HI PRES IS
CENTERED NEAR WRN LK SUP...AND SOME LO CLDS/FOG ARE APRNT OVER WRN
LK SUP NEAR THE W COAST OF UPR MI CLOSER TO MOISTER AIRMASS SHOWN ON
THE 00Z INL RAOB. DESPITE THE LGT WINDS AND TEMPS FALLING TOWARD 30
CLOSER TO THIS MSTR...NO FOG HAS YET FORMED OVER WRN UPR MI AS OF
FCST ISSUANCE.
TODAY/TNGT...UPR RDG IS FCST TO REMAIN DOMINANT THRU THIS TIME WITH
SFC HI PRES REMAINING NEARLY STNRY OVER LK SUP. WITH DRY AIRMASS
ALSO LINGERING...THE ONLY MAJOR CONCERNS ARE TEMPS...THE POTENTIAL
FOR FOG THIS MRNG/TNGT...AND POTENTIAL LOW RH THIS AFTN...ESPECIALLY
OVER THE E HALF CLOSER TO CORE OF DRY AIRMASS. BEST CHC FOR FOG
EARLY THIS MRNG WL BE OVER THE INTERIOR W...CLOSER TO AREA OF FOG/
LO CLD STRETCHING FM THE W SHORE OF THE KEWEENAW DOWN TOWARD
IWD/ASX. ANY FOG THAT DOES DVLP SHOULD BURN OFF FAIRLY QUICKLY WITH
THE ONSET OF DAYTIME HEATING.
WITH H85 TEMPS TOPPING OUT AT 9-10C AGAIN TODAY...EXPECT MAX TEMPS
TO BE SIMILAR TO WHAT OCCURRED YDAY AT MOST LOCATIONS. THE ONLY
EXCEPTION WL BE OVER THE NCENTRAL AND W NEAR LK SUP...WHERE A WEAKER
SYNOPTIC FLOW THAN YDAY WL LIMIT THE INLAND EXTENT OF LK MODERATION.
SO ALTHOUGH TEMPS NEAR THE SHORE IN THIS AREA MIGHT HAVE A HARD TIME
TOPPING 50...MUCH OF THE NCENTRAL AND W WL BE WARMER THAN YDAY.
MIXING TO H8-85 ON NAM/GFS FCST SDNGS YIELDS HI TEMPS UP TO 70-75
OVER THE INTERIOR AWAY FM LOCAL LK BREEZE MODERATION. PREFER THE
DRIER LOOK TO THE NAM FCST SDNGS GIVEN BONE DRY GRB/APX RAOBS. DEEP
MIXING ON THESE FCST SDNGS SUG DEWPTS WL MIX OUT AS LO AS 30 TO 35
OVER THE INTERIOR DURING PEAK HEATING...LOWERING MIN RH AS LO AS
20-25 PCT. THE BEST CHC FOR THE LOWER DEWPTS WL BE OVER THE E WHERE
THE GROUND IS QUITE A BIT DRIER THAN OVER THE W/CENTRAL. FORTUNATELY
WINDS WL BE LGT...SO NO FIRE WX HEADLINES ARE NECESSARY.
FOR TNGT...WITH LGT WINDS AND DRY AIRMASS LINGERING...EXPECT A
HEALTHY DROP OF TEMP. PREFER TO TEND TOWARD THE LOWER END OF
GUIDANCE FOR MIN TEMPS...BUT MODERATING AIRMASS SUGGESTS TEMPS TNGT
WL NOT BE AS CHILLY AS EARLY THIS MRNG. SINCE FOG HAS BEEN SLOW TO
FORM THIS MRNG AND THE LLVLS TNGT WL LIKELY TO BE AS DRY...OPTED TO
MAINTAIN FCST FOR PATCHY FOG ONLY OVER THE INTERIOR W WHERE TEMPS AT
SOME OF THE FAVORED COOL SPOTS SEE MIN TEMPS FALLING TOWARD 33.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 355 AM EDT MON MAY 6 2013
THE QUIET WEATHER WILL CONTINUE FOR THE START OF THE LONG TERM
PERIOD...AS DUAL CUTOFF LOWS /ONE OVER THE SE CONUS AND THE OTHER
NEAR CALIFORNIA/ KEEP THE UNSETTLED WEATHER OVER THE SOUTHERN HALF
OF THE CONUS. MEANWHILE...THE NORTHERN STREAM JET RUNNING WEST-EAST
ACROSS CENTRAL CANADA WILL KEEP THE COLDER AIR LOCKED UP TO THE
NORTH FOR THE TIME BEING.
AT THE SURFACE...HIGH PRESSURE WILL STILL BE OVER THE UPPER GREAT
LAKES FOR TUESDAY INTO WEDNESDAY MORNING AND PRODUCE MOSTLY CLEAR
SKIES ACROSS THE AREA. THERE ARE STILL HINTS OF SOME HIGH-BASED
DIURNAL CU OVER THE WESTERN CWA ON TUESDAY AFTERNOON...BUT NOT
EXPECTING MUCH MORE THAN THAT. WITH THE DEEP MIXING...EXPECT
ANOTHER ABOVE NORMAL DAY OVER THE CWA...WITH HIGHS IN THE 70S
EXCEPT WHERE LAKE BREEZES KEEP TEMPERATURES COOLER NEAR THE GREAT
LAKES. TEMPERATURES SHOULD BE SIMILAR ON WEDNESDAY...ALTHOUGH THE
INCREASING CLOUDS AND POTENTIAL PRECIPITATION MAY KEEP THE WEST
HALF A LITTLE COOLER. DID TREND DEWPOINTS DOWN FOR TUESDAY AFTERNOON
OVER THE CENTRAL AND EAST BASED OFF THE LAST COUPLE OF DAYS. WITH
THE GOOD MIXING THOSE DAYS...RH VALUES FELL INTO THE UPPER TEENS AND
20S AWAY FROM THE LAKE INFLUENCES AND WOULD EXPECT THE SAME FOR
TUESDAY. THAT IDEA MATCHES MIXED LAYER DEWPOINTS FROM THE MODELS AND
TRENDED THAT DIRECTION.
THE FIRST CHANCE OF PRECIPITATION FOR THE LONG TERM PERIOD WILL
COME LATE WEDNESDAY AFTERNOON AND INTO WEDNESDAY NIGHT. THIS IS DUE
TO A SHORTWAVE IN THE NORTHERN STREAM WAVE PRODUCING A LOW THAT
SHIFTS EAST INTO QUEBEC ON WEDNESDAY. A TRAILING COLD FRONT WILL
THEN TRY TO DIVE SOUTHEAST ACROSS THE UPPER GREAT LAKES ON
WEDNESDAY NIGHT INTO THURSDAY MORNING. THE MAIN FORECAST IMPACT IS
WHAT WILL HAPPEN WITH THE MOISTURE AND SMALL CLOSED PIECE OF ENERGY
THAT TRIES TO DRIFT NORTHEAST AND INTERACT WITH THE NORTHERN
STREAM. THE MODELS CONTINUE TO DIFFER WITH THIS INTERACTION AND
PROVIDES UNCERTAINTY IN THE QPF AMOUNTS. WILL CONTINUE TO GO WITH A
GENERAL CONSENSUS POP/QPF DURING THIS PERIOD AND HAVE SLIGHTS
OR LOW CHANCE POPS FOR LATE WEDNESDAY AFTERNOON INTO THURSDAY
MORNING.
WITH THE COLD FRONT MOVING SOUTHEAST OF THE AREA...EXPECT DRIER AIR
TO DIMINISHING PRECIPITATION CHANCES BY THURSDAY AFTERNOON AS A
CANADIAN HIGH PRESSURE RIDGE DROPS OVER THE AREA. THIS RIDGE WILL
REMAIN OVER THE AREA FOR FRIDAY AND LEAD TO DRY BUT COOLER WEATHER
WITH HIGHS IN THE 50S.
A MUCH STRONGER NORTHERN STREAM WAVE WILL BE DIVING SOUTHEAST
TOWARDS THE UPPER GREAT LAKES ON SATURDAY AND BRING MUCH COOLER
WEATHER FOR THE WEEKEND. WILL CONTINUE THE CHANCE POPS WITH THIS
SYSTEM...BUT WITH LITTLE MOISTURE RETURN AHEAD OF THE WAVE...QPF
AMOUNTS WILL BE ON THE LIGHT SIDE. PRECIPITATION SHOULD FALL AS
RAIN...AS THE COLDEST AIR DOESN/T ARRIVE UNTIL AFTER MOST OF THE
DEEP MOISTURE EXITS. WITH THE BETTER CONSISTENCY IN THE MODELS FOR
THIS WAVE...HAVE TRENDED HIGHS DOWN INTO THE UPPER 40S OR LOWER 50S
FOR SATURDAY ALTHOUGH THERE IS SOME CONCERNS THE EAST COULD SEE
WARMER HIGHS AROUND DAYBREAK AND THEN FALLING THROUGH THE DAY. THE
TROUGH WILL QUICKLY SHIFT EAST TO THE NEW ENGLAND STATES ON SUNDAY
AND ALLOW RETURN FLOW TO DEVELOP. SUNDAY SHOULD BE DRY BUT COOL BUT
THEN WARMING IS EXPECTED FOR THE FIRST PART OF NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 123 AM EDT MON MAY 6 2013
DRIER AIR OVER THE AREA HAS LIMITED FOG DEVELOPMENT OVERNIGHT
DESPITE DECENT ANTECEDENT MOISTURE LEFT OVER FROM THE SNOWMELT AND
RECENT PRECIPITATION. WHILE FOG REMAINS A POSSIBILITY...VISIBILITIES
WILL NOT BE RESTRICTED BELOW MVFR...EXCEPT AT IWD WHERE IFR
CONDITIONS MAY RESULT CLOSER TO FOG ALREADY OVER LAKE SUPERIOR. ANY
FOG THAT DEVELOPS WILL QUICKLY BURN OFF AFTER SUNRISE LEAVING THE
THREE TAF SITES UNDER VFR CONDITIONS THROUGH 0Z TUESDAY. LATEST NAM
ON BUFKIT SHOWS POSSIBILITY OF LOW CLOUDS AND FOG REDEVELOPING AT
KCMX AFTER 0Z TUESDAY...BUT HAVE NOT INCLUDED IT IN THE FORECAST AT
THIS TIME.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 355 AM EDT MON MAY 6 2013
A QUIET PERIOD OF WEATHER IS EXPECTED THROUGH THE PERIOD...WITH THE
WINDS LIKELY STAYING BELOW 25KTS. HIGH PRESSURE THAT HAS SETUP OVER
THE AREA WILL REMAIN THROUGH WEDNESDAY MORNING AND LEAD TO LIGHT
WINDS. THEN...A COLD FRONT DROPPING SOUTHEAST ACROSS THE UPPER GREAT
LAKES ON WEDNESDAY NIGHT WILL BRING A WIND SHIFT BUT ONLY 10-20KT
WINDS. WEAK HIGH PRESSURE WILL MOVE OVER NORTHERN LAKE SUPERIOR FOR
THURSDAY AFTERNOON INTO FRIDAY AND DIMINISH THE WINDS.
&&
.HYDROLOGY...
ISSUED AT 355 AM EDT MON MAY 6 2013
HYDROLOGY CONCERNS WILL REMAIN OVER THE COMING DAYS...UNTIL THE
REMAINING SNOW PACK MELTS OVER THE NORTHWESTERN THIRD OF UPPER
MICHIGAN. VISIBLE SATELLITE AND MODIS IMAGERY YESTERDAY STILL SHOWS
SNOW REMAINING IN THE HIGHER TERRAIN LOCATIONS OF THE HURON
MOUNTAINS AND THE KEWEENAW PENINSULA. DID SEE RISES AT SOME OF THE
SITES OVER THE WEST /ESPECIALLY TRRM4/ WITH THE WARMER TEMPERATURES
YESTERDAY AND WOULD EXPECT THAT TO CONTINUE UNTIL THE REMAINING
SNOW IS GONE. AT THIS TIME...WOULD THINK TRRM4 WILL BE THE MAIN
THREAT FOR REACHING ADVISORY OR FLOOD STAGE FROM THIS ADDITIONAL
MELT.
OTHERWISE...THE ONGOING FLOODING ON THE STURGEON RIVER AT ALSTON AND
CHASSELL...THE MICHIGAMME RIVER AROUND WITCH LAKE...AND THE PAINT
RIVER NEAR CRYSTAL FALLS WILL REMAIN A CONCERN FOR THE NEXT COUPLE
OF DAYS. THE REST RIVER LEVELS ARE ON THE DOWNWARD TREND AND
WILL LIKELY CONTINUE THIS WEEK.
FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD WARNINGS AND
ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...SRF
AVIATION...RJT/KC
MARINE...SRF
HYDROLOGY...SRF
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
408 AM CDT MON MAY 6 2013
.SYNOPSIS...
ISSUED AT 407 AM CDT MON MAY 6 2013
H5 ANALYSIS TONIGHT HAS THREE AREAS OF CLOSED LOW
PRESSURE OVER THE CONUS. THE FIRST WAS OVER NRN ALABAMA...THE SECOND
OFF THE NRN CA COAST AND A THIRD WEAKER SYSTEM WAS NOTED OVER
CENTRAL SOUTH DAKOTA. AT THE SURFACE...WEAK HIGH PRESSURE WAS
ANCHORED ACROSS NORTHERN NEBRASKA AND SOUTHERN SOUTH DAKOTA ATTM.
RADIATIONAL COOLING UNDERNEATH THE HIGH...HAS LED TO SOME PATCHY FOG
ACROSS NORTHEASTERN PORTIONS OF THE FORECAST AREA OVER THE PAST
HOUR...WITH VISBYS DOWN TO QUARTER MILE AT ONEILL. COMPARED TO 24
HOURS AGO...TEMPERATURES ARE MUCH WARMER ATTM WITH 3 AM CDT TEMPS
RANGING FROM THE LOWER 30S IN THE NORTHEAST...TO THE LOWER 40S IN
THE EASTERN PANHANDLE AND FAR SOUTHWESTERN NEBRASKA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 407 AM CDT MON MAY 6 2013
THE MAIN FORECAST CHALLENGES OVER THE NEXT 24 HOURS ARE
TEMPERATURES TODAY...AND THE THREAT FOR THUNDERSTORMS LATER
TONIGHT. FOR THIS MORNING...OBSERVATIONS...SATELLITE IMAGERY AND
HIGHWAY CAMS...CONTINUE TO INDICATE FOG ACROSS THE NORTHEASTERN
CWA ATTM. THE LATEST VISIBILITY FOR ONEILL IS AROUND A QUARTER
MILE. DECIDED TO HOIST A DENSE FOG ADVISORY TO COVER THIS THREAT
THROUGH MID MORNING. ATTM...THE DENSE FOG THREAT APPEARS LOCALIZED
WITH THE LOWEST VISBYS IN LOW LYING AREAS AND RIVER VALLEYS. BASED
ON THE HRRR AND NAM12 BL RH FIELD...FOG SHOULD QUICKLY BURN OFF BY
MID MORNING...WITH VISBYS IMPROVING QUICKLY AFTER 14Z. BASED ON
THE HRRR...THE GREATEST THREAT FOR FOG SHOULD REMAIN ALONG AND
EAST OF HIGHWAY 183. FOR THE REMAINDER OF TODAY...SRLY WINDS WILL
INCREASE THIS AFTERNOON AS HIGH PRESSURE MOVES EAST OF THE
AREA...AND LEE TROUGHING DEEPENS ACROSS EASTERN WYOMING AND
EASTERN COLORADO. THE SRLY WINDS...WILL PUSH WARMER AIR AND
INCREASED LOW LEVEL MOISTURE FROM THE SRN PLAINS INTO WESTERN AND
NORTH CENTRAL NEBRASKA. THIS WILL RESULT IN HIGHS IN THE MID TO
UPPER 60S THIS AFTERNOON...WHICH IS A SMALL DECREASE IN THE LOWER
70S IN THE INHERITED FCST. HIGHS WERE LOWERED AS I AM ANTICIPATING
ADDITIONAL HIGH CLOUDINESS TO PUSH INTO THE FORECAST AREA LATER
THIS AFTERNOON FROM THE SRN ROCKIES. THIS CLOUDINESS IS IN ADVANCE
OF AN APPROACHING DISTURBANCE...WHICH WILL BEGIN TO IMPACT THE
FORECAST AREA LATER TONIGHT.
PRECIPITATION CHANCES WILL BEGIN TO INCREASE OVERNIGHT TONIGHT AS
MID LEVEL WAA BEGINS TO LIFT INTO THE CENTRAL PLAINS IN ADVANCE OF
AN APPROACHING UPPER LEVEL DISTURBANCE. ELEVATED INSTABILITY WILL
INCREASE OVERNIGHT PER H800 CALCULATED LI`S RANGE FROM -1 TO -3
OVERNIGHT ACROSS CENTRAL AND NORTHERN NEBRASKA. ADDITIONAL FORCING
FOR TSRAS WILL COME FROM THE DEVELOPMENT OF A 30 KT LLJET WHICH WILL
EXTEND FROM WESTERN KS INTO SWRN NEBRASKA AFTER 06Z TONIGHT.
COVERAGE OF TSRAS IS EXPECTED TO BE LIMITED THOUGH AS SURFACE DEW
POINTS WILL ONLY BE IN THE LOWER TO MID 40S. ATTM...NO SEVERE
THUNDERSTORMS ARE EXPECTED OVERNIGHT...AS LIFT AND AVAILABLE CAPE
WILL BE LIMITED.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 407 AM CDT MON MAY 6 2013
BY TUESDAY MORNING THERE REALLY WON/T BE MUCH MOVEMENT IN THE
PRIMARY UPPER LEVEL SYSTEMS ACROSS THE CONUS. THE UPPER LOW OVER
THE SOUTHEAST PART OF THE COUNTRY WILL HAVE MOVED INTO THE
CAROLINAS...WHILE THE SYSTEM OFF THE CALIFORNIA COAST WILL JUST BE
MOVING ONSHORE BY 12Z TUESDAY. ALSO...THE WEAK UPPER LOW NOW OVER
SOUTH DAKOTA WILL STAY STATIONARY THROUGH TUESDAY MORNING.
MODEL SOLUTIONS HAVE STARTED TO BECOME MORE IN LINE FOR TUESDAY.
THE SYSTEM OVER THE SOUTHEAST WILL SLOWLY LIFT NORTH ALONG THE
EAST COAST THROUGH THE WEEK...WHILE THE CALIFORNIA LOW MOVES
ONSHORE TUESDAY AND INTO THE GREAT BASIN TUESDAY NIGHT.
MEANWHILE...THE WEAK UPPER LOW OVER THE DAKOTAS WILL STAY IN THE
AREA THROUGH AT LEAST TUESDAY NIGHT AS THE NORTHERN STREAM STAYS
WELL TO THE NORTH LEAVING NOTHING TO KICK IT OUT OF THE AREA.
MEANWHILE...A WEAK SHORTWAVE TROUGH EJECTS OUT OF THE WEST COAST
TROUGH AND PUSHES INTO THE CENTRAL PLAINS. PRECIPITATION CHANCES
WILL INCREASE LATER TUESDAY AFTERNOON AND TUESDAY NIGHT AHEAD OF
THE SHORTWAVE TROUGH MOVING INTO THE AREA. MOISTURE WILL BE ON THE
RISE ON TUESDAY AHEAD OF THIS FEATURE AS WELL...WITH THE MODELS
BEING FAIRLY IN TUNE WITH EACH OTHER BRINGING IN 50 DEGREE
DEWPOINTS INTO THE EASTERN PARTS OF THE FORECAST AREA. THIS
MOISTURE ALONG WITH SOME COOLER TEMPERATURES ALOFT /THANKS TO THE
UPPER LOW HANGING AROUND/ WILL CAUSE THE AIR TO BE UNSTABLE FOR
THUNDERSTORMS MAINLY STARTING TUESDAY AFTERNOON. LOOKING FOR QUITE
A BIT OF CLOUD COVER THROUGH THE DAY TUESDAY AND WITH AT LEAST
PERIODIC SHOWERS AND THUNDERSTORMS...NOT EXPECTING TEMPERATURES TO
BE TOO WARM AND ACTUALLY COOLED THEM A FEW DEGREES FROM THE
PREVIOUS FORECAST.
MODEL AGREEMENT CONTINUES THROUGH THE DAY WEDNESDAY AS A SHORTWAVE
MOVING THROUGH THE NORTHERN STREAM DROPS FAR ENOUGH SOUTH TO CATCH
THE DAKOTA UPPER LOW AND FINALLY PUSH IT EASTWARD. AT THIS POINT
THE CALIFORNIA UPPER LOW WILL HAVE MOVED INTO THE FOUR CORNERS.
THIS MAKES WEDNESDAY LOOK DRIER THAN WAS PREVIOUSLY FORECAST AS
THE AREA SITS IN A SUBSIDENT REGION BEHIND THE PASSING UPPER LOW
AND TOO FAR AHEAD OF THE FOUR CORNERS LOW TO REALLY EXPECT MUCH
FOR PRECIPITATION. AT THIS POINT...DIDN/T GO COMPLETELY DRY FOR
WEDNESDAY...AS THERE IS STILL A LACK OF CONFIDENCE IN THE MODEL
SOLUTIONS. AT THIS POINT TRENDED PRECIPITATION FORECAST
LOWER...WITH THE BETTER CHANCES FOR RAIN ACROSS THE SOUTHERN PARTS
OF THE FORECAST AREA. IN TURN...WITH LESSER PRECIPITATION
EXPECTED...INCREASED TEMPERATURES A BIT FOR WEDNESDAY. THERE DOES
LOOK TO BE A WARM FRONT LOCATED SOMEWHERE ACROSS KANSAS ON
WEDNESDAY AFTERNOON...WHICH SHOULD BE THE FOCUS FOR STORM
DEVELOPMENT. INSTABILITY IS DECENT...AND SHEAR IS BETWEEN 35 AND
45KTS SO COULD SEE SOME STRONGER STORMS. THIS BEING SAID...CURRENT
THINKING IS THAT MOST OF THIS ACTIVITY WILL STAY SOUTH OF THE
LOCAL AREA...MAINLY IN FAR SOUTHERN NEBRASKA AND KANSAS. BUT IF
THIS BOUNDARY MEANDERS MAY NEED TO ADJUST THIS THINKING NORTHWARD.
AT THIS POINT MODEL DIVERGENCE BEGINS WITH HOW THE UPPER LOW TO
THE SOUTHWEST WILL PROGRESS. THE ECMWF AND GFS ARE FOR THE MOST
PART BOTH WEAKENING THE LOW AND DEVELOPING ANOTHER OVER NORTHWEST
MEXICO. THE GEM ON THE OTHER HAND QUICKLY PUSHES EVERYTHING TO THE
EAST. CONFIDENCE LESSENS WITH PRECIPITATION CHANCES FOR THURSDAY
AND FRIDAY...BUT THERE REMAINS SOME WEAK SIGNALS SO KEPT IT IN THE
FORECAST FOR NOW.
GOING INTO THE WEEKEND...A STRONG RIDGE BUILDS OVER THE WEST
COAST. IN TURN...AN UPPER LEVEL TROUGH DIGS SOUTH ACROSS THE
NORTHERN PLAINS AND GREAT LAKES REGION. THIS WILL PUSH A PRETTY
STRONG COLD FRONT ACROSS THE AREA...MOST LIKELY SOMETIME SATURDAY
MORNING. MAY HAVE A CHANCE FOR SOME SHOWERS WITH THE FRONTAL
PASSAGE...BUT THE MAIN IMPACT WILL BE AGAIN PUSHING THE NEAR
NORMAL TEMPERATURES SOUTHWARD...WITH TEMPERATURES AROUND 60 OR
LOWER POSSIBLE FOR SATURDAY. ALSO...WITH THE COLDER AND DRIER
AIRMASS ASSOCIATED WITH THIS SYSTEM...COULD ONCE AGAIN SEE LOWS
SUNDAY MORNING IN THE MID 30S OR EVEN LOWER IN SOME LOCATIONS. IN
BOTH CASES...DID NOT GO TO THE EXTREME AS THERE WILL LIKELY BE
SOME CHANGES IN MODEL SOLUTIONS OVER THE NEXT SEVERAL DAYS.
INSTEAD...JUST TRENDED COLDER FOR BOTH PERIODS. THE LONG TERM
MODELS ARE FAIRLY PROGRESSIVE WITH THE UPPER FLOW FOR THE WEEKEND
AND EARLY NEXT WEEK THOUGH SO THIS WOULD INDICATE THIS COLD SPELL
WILL BE QUITE SHORT LIVED...WITH HIGHS RECOVERING TO AROUND 70 FOR
SUNDAY AND POSSIBLY NEARING 80 BY MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1225 AM CDT MON MAY 6 2013
VISUAL FLIGHT RULES WILL CONTINUE OVER WESTERN NEBRASKA THROUGH
MONDAY. LIGHT AND VARIABLE WINDS WILL INCREASE AND BECOME SOUTHEAST
MONDAY AFTERNOON TO AROUND 10KTS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ007-010-
028-029.
&&
$$
SYNOPSIS...CLB
SHORT TERM...BROOKS
LONG TERM...BROOKS
AVIATION...POWER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
403 AM CDT MON MAY 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 403 AM CDT MON MAY 6 2013
OVERNIGHT UPPER AIR ANALYSIS INDICATES A MID TO UPPER LEVEL OMEGA
PATTERN WITH MID TO UPPER LEVEL LOWS OVER THE WESTERN AND
SOUTHEASTERN CONUS...AND RIDGING OVER THE CENTRAL CONUS. MID AND
UPPER LEVEL JET ENERGY REMAINS RELEGATED WELL TO OUR SOUTH AND AS
A RESULT...MID AND UPPER LEVEL FLOW OVER THE CENTRAL PLAINS
REMAINS VERY WEAK. WATER VAPOR IMAGERY SHOWS THE TWO
AFOREMENTIONED MID LEVEL LOWS...WITH INCREASED VALUES OF MID LEVEL
MOISTURE WRAPPING AROUND THE SOUTHEASTERN CONUS LOW INTO PORTIONS
OF THE OHIO RIVER VALLEY AND THE MID MISSISSIPPI VALLEY...AND
INCREASED VALUES OF MID LEVEL MOISTURE ALSO NOTED OVER THE WESTERN
CONUS AHEAD OF THE WESTERN CONUS LOW. WATER VAPOR IMAGERY ALSO
INDICATES A SUBTLE MID LEVEL SHORT WAVE OVER THE SOUTHWESTERN
CONUS...PIVOTING TO THE SOUTHEAST OF THE WESTERN CONUS MID LEVEL
LOW. AT THE SURFACE A RIDGE OF HIGH BAROMETRIC PRESSURE EXISTS
FROM NORTH TO SOUTH ACROSS OUR CWA AND AS A RESULT...THE LOW LEVEL
WIND FIELD ACROSS OUR AREA REMAINS LIGHT. THE LIGHT LOW LEVEL WIND
FIELD...WORKING IN CONCERT WITH DECREASING LOW LEVEL DEWPOINT
DEPRESSIONS...HAS PROMOTED THE DEVELOPMENT OF FOG ACROSS MUCH OF
OUR AREA THIS MORNING.
GIVEN THE CURRENT FOG BEING OBSERVED ACROSS THE AREA...WILL
CONTINUE FOG MENTION IN THE FORECAST THROUGH 14Z THIS MORNING. AS
OF 09Z KODX...KHSI AND KAUH HAVE DROPPED TO 1/4SM WITH SEVERAL
OTHER SITE IN THE AREA ALSO DROPPING NEAR 1/4SM. GIVEN ALL
THIS...WENT AHEAD WITH A DENSE FOG ADVISORY...FOR LOCATIONS
GENERALLY EAST OF A KODX TO KEAR LINE AND NORTH OF HIGHWAY 6. THIS
FOG APPEARS TO BE VERY SHALLOW...BASED ON LAPS AND RAP ANALYSIS
POINT SOUNDINGS AS WELL AS OBSERVATION HERE AT THE OFFICE. AS A
RESULT...INCREASED DIABATIC HEATING AND RESULTANT INCREASING
BOUNDARY LAYER DEPTH AND MIXING SHOULD ALLOW THE FOG TO QUICKLY
DISSIPATE POST-SUNRISE...WITH FULL VISIBILITY EXPECTED AT MOST
SITES BY 14Z.
AN OVERALL LACK IN KINEMATIC FORCING IS EXPECTED TO KEEP OUR AREA
DRY TODAY. THE SUBTLE MID LEVEL SHORT WAVE...CURRENTLY OVER THE
SOUTHWESTERN CONUS...IS EXPECTED TO CONTINUE MOVING EAST/NORTHEAST
TODAY AND BY THIS EVENING...SHOULD BE MOVING ACROSS THE SOUTHERN
TO CENTRAL ROCKY MOUNTAIN RANGE. MID LEVEL THERMAL ADVECTION AND
RESULTANT OMEGA AHEAD OF THE SHORT WAVE TROUGH AXIS APPEARS AS
THOUGH IT WILL BE STRONG ENOUGH FOR PRECIPITATION PRODUCTION
ACROSS THE SOUTHERN TO CENTRAL HIGH PLAINS LATE THIS AFTERNOON
INTO THIS EVENING. SHORTLY AFTER SUNSET TONIGHT...A ~30KT 850MB
JET STREAK IS EXPECTED TO DEVELOP FROM SOUTH TO NORTH ACROSS THE
SOUTHERN AND CENTRAL HIGH PLAINS. THIS 850MB JET STREAK IS THEN
EXPECTED TO PROPAGATE EAST SOMEWHAT DURING THE OVERNIGHT HOURS AND
BY 12Z TUESDAY...THE EASTERN PERIPHERY OF THIS 850MB JET AXIS WILL
BRUSH UP AGAINST WEST/SOUTHWESTERN PORTIONS OF OUR CWA. LOW LEVEL
THERMAL ADVECTION ALONG THE 850MB JET STREAK AXIS APPEARS AS
THOUGH IT WILL ALLOW LATE AFTERNOON/EVENING PRECIPITATION ACROSS
THE HIGH PLAINS TO HOLD TOGETHER POST-SUNSET...AND MOVE INTO
WESTERN/SOUTHWESTERN PORTIONS OF OUR CWA 06-12Z TUESDAY. THIS IS A
SOLUTION SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL
GFS...EC AND SREF-MEAN. GIVEN THE MODEL AGREEMENT AND THE APPARENT
LIKELIHOOD THAT SOME LOCATIONS ACROSS OUR WEST/SOUTHWEST COULD
PICKUP UPWARDS OF A TENTH OF AN INCH OF PRECIPITATION...OPTED TO
INCREASE POPS INTO THE 40-50% RANGE ACROSS OUR FAR WEST/SOUTHWEST
06-12Z TUESDAY. LOCATIONS FATHER EAST/NORTHEAST ALSO HAVE POPS IN
PLACE FOR TONIGHT...ALBEIT SUBSTANTIALLY LOWER IN THE 20-30% RANGE
AS CONFIDENCE IS NOT NEARLY AS HIGH THAT FAR EAST WITH THE 850MB
JET STREAK AXIS EXPECTED TO REMAIN FARTHER WEST.
MOISTURE FLUX ALONG THE 850MB JET STREAK AXIS...AS WELL AS THE
700MB JET STREAK AXIS...WORKING IN CONCERT WITH INCREASING MID
LEVEL LAPSE RATES WITH THE APPROACH OF THE SUBTLE MID LEVEL SHORT
WAVE...IS EXPECTED TO PROVIDE INCREASING POTENTIAL INSTABILITY
ACROSS OUR AREA TONIGHT. THE NAM IN PARTICULAR SUGGESTS PARCELS
ROOTED TO BETWEEN 850MB AND 750MB WILL HAVE 50-100J/KG OF CAPE TO
WORK WITH AND CIN RANGING BETWEEN NEAR-ZERO AND AROUND -20J/KG.
GIVEN ALL THIS...ISOLATED CONVECTION CERTAINLY SEEMS POSSIBLE
EMBEDDED WITHIN THE STRATIFORM RAIN EVENT OCCURRING ALONG THE LOW
LEVEL JET AXIS. GIVEN ALL THIS WENT AHEAD AND ADDED ISOLATED
THUNDER MENTION TO THE FORECAST FOR OUR CWA FOR TONIGHT.
THE SURFACE RIDGE CURRENTLY OVER THE AREA IS EXPECTED TO PUSH EAST
LATER TODAY...ALLOWING FOR WEAK LOW LEVEL RETURN FLOW ACROSS MUCH
OF OUR AREA BY THIS AFTERNOON. SUBTLE LOW LEVEL WARM AIR
ADVECTION...AS WELL AS INCREASED DIABATIC HEATING...WHEN COMPARED
TO SUNDAY SHOULD ALLOW FOR A WARMER DAY ACROSS OUR CWA TODAY. AN
AFTERNOON HIGH TEMPERATURE IN THE UPPER 60S TO LOWER 70S IS
FORECAST FOR MOST LOCATIONS FOR TODAY AS A RESULT. INCREASING
CLOUD COVER...POSSIBLE PRECIPITATION...AND CONTINUED SOUTHEASTERLY
LOW LEVEL FLOW SHOULD PRESENT A WARMER OVERNIGHT LOW TEMPERATURE
TONIGHT WHEN COMPARED TO EARLY THIS MORNING. A TUESDAY MORNING LOW
TEMPERATURE IN THE MID TO UPPER 40S IS FORECAST FOR MOST LOCATIONS
ACROSS OUR CWA AS A RESULT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 403 AM CDT MON MAY 6 2013
TUESDAY THROUGH SUNDAY. MAIN FORECAST CONCERNS WILL BE CHANCES FOR
SHOWERS AND THUNDERSTORMS TUESDAY THROUGH SATURDAY AND
TEMPERATURES.
AN UNSETTLED PATTERN WILL BE FOUND ACROSS THE CENTRAL PLAINS FOR
TUESDAY THROUGH SATURDAY. A WEAK RIDGE SETS UP BETWEEN A STRONG
UPPER LEVEL LOW TO THE WEST AND ANOTHER TO THE EAST. DESPITE THE
RIDGE...THERE WILL BE SEVERAL RELATIVELY WEAK UPPER LEVEL LOW
PRESSURE SYSTEMS THAT WILL AFFECT THE AREA FOR THE TUESDAY THROUGH
SATURDAY PERIOD. DO NOT EXPECT THAT IT WILL BE RAINING ALL OF THE
TIME FOR EACH OF THESE PERIODS...BUT THERE IS A CHANCE FOR SHOWERS
AND THUNDERSTORMS ON AND OFF THROUGH THE PERIOD. THE STRONGEST
UPPER LEVEL LOWS THAT MOVE THROUGH THE AREA WILL BE FOR TUESDAY
AND TUESDAY NIGHT AND AGAIN WEDNESDAY NIGHT. THESE WILL BRING THE
BEST CHANCES FOR PRECIPITATION. THE MUCAPE FOR TUESDAY AFTERNOON
AND EVENING WILL REACH AROUND 750 J/KG WHICH SHOULD BE ENOUGH FOR
SOME ISOLATED SEVERE WEATHER...BUT WEDNESDAY AFTERNOON AND EVENING
MUCAPE VALUES APPROACH 2500 J/KG WHICH WOULD INDICATE A BETTER
CHANCE FOR SOME SEVERE STORMS. THERE ARE STILL SOME DIFFERENCES IN
THE MODELS AND WILL HAVE TO WATCH TO SEE HOW MUCH CHANGE THERE IS
OVER THE NEXT COUPLE DAYS.
FOR THURSDAY THROUGH SATURDAY THE UPPER LEVEL LOW IN THE WESTERN
CONUS WILL DRIFT TO THE EAST AND INTO THE PLAINS. THIS WILL
CONTINUE TO BRING CHANCES FOR SHOWERS WITH SOME ISOLATED
THUNDERSTORMS. MU CAPE VALUES DECREASE TO LESS THAN 200 J/KG.
TEMPERATURES SHOULD REMAIN AROUND NORMAL FOR THIS TIME OF YEAR
THROUGH FRIDAY...BUT AS A COLD FRONT MOVES SOUTH INTO THE AREA ON
SATURDAY EXPECT SOME SHOWERS AND THUNDERSTORMS BEHIND THE FRONT
AND TEMPERATURES WILL COOL OFF A FEW DEGREES. A COOL SURFACE HIGH
PRESSURE SYSTEM SETTLES INTO THE REGION FOR SATURDAY NIGHT INTO
SUNDAY AND TEMPERATURES WILL REMAIN A BIT COOLER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1229 AM CDT MON MAY 6 2013
VFR CONDITIONS EXPECTED THROUGH MUCH OF THE TAF PERIOD...ALTHOUGH
IFR CONDITIONS WILL BE POSSIBLE 10-14Z.
SCATTERED MID TO HIGH LEVEL CLOUDS WILL CONTINUE AT KGRI THROUGH
THE NEXT 24 HOURS. THE PRESENCE OF A SURFACE RIDGE WILL KEEP THE
SURFACE WIND LIGHT AND VARIABLE THROUGH TONIGHT...BEFORE BECOMING
MORE ESTABLISHED FROM THE SOUTHEAST DURING THE DAY MONDAY. A
DECREASING LOW LEVEL DEWPOINT DEPRESSION...WORKING IN CONCERT WITH
THE AFOREMENTIONED LIGHT SURFACE WIND...MAY PROMOTE FOG
DEVELOPMENT AT KGRI BETWEEN 10Z AND 14Z THIS MORNING. CONFIDENCE
OF SUCH VISIBILITY RESTRICTION ACTUALLY OCCURRING IS ABOUT
50%...WITH THE SITUATION LIKELY BECOMING MORE CLEAR BETWEEN 10Z
AND 12Z. FOR NOW WILL GO WITH A PREVAILING IFR VISIBILITY AND AN
MVFR CEILING...PER GUIDANCE...10-14Z AND IF NECESSARY...UPDATE AS
WE APPROACH SUNRISE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR NEZ039>041-
046>049-061>064-074>077.
KS...NONE.
&&
$$
SHORT TERM...BRYANT
LONG TERM...JCB
AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1229 AM CDT MON MAY 6 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 345 PM CDT SUN MAY 5 2013
OTHER THAN THE FAIRLY LOW PROBABILITY OF SOME PATCHY FOG
OVERNIGHT...THE NEXT 24 HOURS ARE LOOKING DRY AND RATHER
UNEVENTFUL...AS TEMPERATURES FINALLY MAKE A LEGITIMATE RUN BACK
TOWARD 70 DEGREES ON MONDAY.
19Z OBJECTIVE SURFACE ANALYSIS HIGHLIGHTS A BROAD...ROUGHLY 1022
MILLIBAR NORTH-SOUTH ORIENTED RIDGE AXIS EXTENDING SOUTHWARD
ACROSS THE CENTRAL CONUS...IN THE WAKE OF THE DEPARTED SURFACE LOW
REFLECTION OF THE SLOW-MOVING CUT OFF UPPER LOW. BREEZES THIS
AFTERNOON ACROSS THE CWA ARE GENERALLY OUT OF THE NORTH AT
SUSTAINED SPEEDS 10-15 MPH WITH SOME HIGHER GUSTS. ALOFT...WATER
VAPOR IMAGERY AND SHORT TERM MODEL DATA HIGHLIGHT A SPLIT-FLOW
UPPER AIR PATTERN THAT WILL DEFINE MUCH OF THE WEEK...WITH THE
CENTRAL PLAINS LOCATED NORTH OF THE SOUTHERN STREAM AND SOUTH OF
THE NORTHERN STREAM. DIRECTLY OVERHEAD IN THE MID LEVELS...FAIRLY
WEAK WEST-NORTHWEST FLOW PREVAILS...AS THE CENTRAL PLAINS LIES IN
BETWEEN TWO DOMINANT CLOSED 500 MILLIBAR LOWS..ONE DEPARTING
ACROSS THE SOUTHEAST STATES...AND ANOTHER CENTERED JUST OFF THE
CA COAST. IN BETWEEN...A MID/UPPER RIDGE EXTENDS NORTH TOWARD THE
CENTRAL PLAINS FROM MEXICO...BUT WITH ANOTHER SMALL-SCALE CUT
CLOSED MID LEVEL LOW SPINNING JUST TO THE NORTH OVER SD. AS
OUTLINED IN THE EARLIER DISCUSSION...SKY COVER AND RESULTANT TEMPS
WERE AT THE MERCY OF LOW STRATUS SCATTERING OUT AND/OR CLEARING
FROM WEST-EAST...AND ALL THINGS CONSIDERED...THINGS HAVE ACTUALLY
WORKED OUT FAIRLY WELL WITH ROUGHLY THE WESTERN 2/3 OF THE CWA NOW
PREDOMINANTLY SUNNY-PARTLY CLOUDY AT THIS HOUR...WHILE MOSTLY
CLOUDY SKIES ARE HANGING ON LONGER MAINLY EAST OF HIGHWAY 14.
HIGH TEMPS APPEAR ON TRACK TO RANGE FROM THE UPPER 50S NORTHEAST
TO MID 60S SOUTHWEST. FORTUNATELY FOR FIRE WEATHER CONCERNS...WINDS
ARE GUSTING WELL UNDER 25 MPH...AS DEWPOINTS HAVE CRASHED ENOUGH
TO DROP RELATIVE HUMIDITY VALUES TO NEAR/SLIGHTLY BELOW 20 PERCENT
IN THE EXTREME WESTERN CWA...MAINLY WESTERN DAWSON/GOSPER/FURNAS
COUNTIES.
HEADING INTO THIS EVENING/TONIGHT...WILL RUN WITH THE ASSUMPTION
THAT THE CURRENTLY ERODING STRATUS DECK WILL CONTINUE TO FADE AWAY
EASTWARD WITH TIME INTO THE OAX/TOP AREAS...AND NOT COMPLETELY
STALL OUT IN OUR EASTERN COUNTIES OR EVEN PUSH BACK WEST.
HOWEVER...AM NOT 100 PERCENT CONFIDENT IN THIS...GIVEN THAT
STEERING FLOW AT 900MB DOES TURN MORE EASTERLY TONIGHT...SO WILL
HAVE TO KEEP AN EYE ON THESE LOW LEVEL CLOUD TRENDS. OTHERWISE...A
GRADUAL INCREASE IN MAINLY THIN MID/HIGH CLOUDS WILL OCCUR
TONIGHT...IN RESPONSE TO SUBTLE...LOW AMPLITUDE ENERGY LIFTING
NORTHEAST TOWARD THE CENTRAL PLAINS OUT AHEAD OF THE AFOREMENTIONED
WESTERN CONUS PARENT TROUGH/CLOSED LOW. GIVEN THAT SKIES SHOULD
GENERALLY AVERAGE PARTLY CLOUDY OVERNIGHT...ESPECIALLY WEST...AM
NOT ANTICIPATING IDEAL RADIATIONAL COOLING CONDITIONS DESPITE THE
CONTINUED PRESENCE OF THE LOW LEVEL RIDGE AXIS SITTING DIRECTLY
OVER THE AREA...WHICH WILL RESULT IN SEVERAL HOURS OF GENERALLY
LIGHT/VARIABLE TO EASTERLY BREEZES. FOR LOW TEMPS...SLIGHTLY
UNDERCUT A BLEND OF 12Z MET/MAV GUIDANCE...WHICH RESULTS IN THE
MAJORITY OF THE AREA BOTTOMING OUT BETWEEN 38-43...AND MAYBE DOWN
AROUND 36 IN THE COLDER-PRONE WESTERN DAWSON COUNTY AREA. THAT
BEING SAID...IF SKIES AVERAGE CLEARER THAN ANTICIPATED...COULD SEE
MORE OF THE CWA MAKE A RUN TOWARD THE MID 30S...AND THIS WILL NEED
WATCHED IN CASE A FEW SPOTS FLIRT WITH FROST-WORTHY READINGS. FOR
NOW...HAVE LEFT OUT FROST MENTION ALL AREAS. HOWEVER...HAVE LEFT
IN A MENTION OF PATCHY FOG CWA-WIDE FROM 09Z-13Z AS THE LIGHT WIND
REGIME COULD PROMOTE SOME DEVELOPMENT. THIS WOULD GENERALLY SEEM
MOST FAVORED WITHIN THE EASTERN 1/2 OF THE CWA IN CLOSEST
PROXIMITY TO THE WEST EDGE OF LOWER STRATUS...AND ALSO OVER WHERE
A BIT MORE LIGHT PRECIP FELL DURING THE PAST FEW DAYS. FOR
NOW...AM NOT EXPECTING SIGNIFICANT VISIBILITY ISSUES...BUT ITS
WORTH NOTING THAT THE LATEST HRRR ACTUALLY DOES SUGGEST SOME
DENSER FOG DEVELOPMENT MAINLY EAST OF HIGHWAY 281...SO THIS ALSO
BEARS WATCHING.
TURNING TO THE DAYTIME HOURS MONDAY...THE OVERALL MID/UPPER AIR
PATTERN CHANGES LITTLE...AS THE CENTRAL PLAINS REMAIN UNDER FAIRLY
UNEVENTFUL QUASI-ZONAL FLOW ALOFT...AND STILL DOWNSTREAM FROM A
LEAD SHORTWAVE EJECTING NORTHEAST TOWARD THE REGION FROM THE
DESERT SOUTHWEST...WHICH COULD PROMOTE SOME RAIN CHANCES MONDAY
NIGHT AS DESCRIBED BELOW. IN ADDITION...JUST TO THE NORTH THE
COMPACT LITTLE CLOSED LOW OVER SD SHOULD PRETTY MUCH REMAIN IN
PLACE...WITH LITTLE CONSEQUENCE INTO NEB/KS. AT THE SURFACE...THE
RIDGE AXIS WILL ONLY SLOWLY EDGE EAST DURING THE DAY...PROVIDING A
DAY OF FAIRLY LIGHT BREEZES. EVEN DURING THE AFTERNOON...THE
EASTERN 1/2 OF THE CWA WILL ONLY AVERAGE AROUND 5 MPH...WHILE
WESTERN COUNTIES PICK UP A SLIGHTLY STRONGER EAST-SOUTHEAST BREEZE
OF 10 TO POSSIBLY 15 MPH. ASSUMING THAT SKIES AVERAGE MOSTLY
CLEAR/PARTLY CLOUDY UNDER ONLY PASSING MID-HIGH CLOUDS...SHOULD
SEE A NICE JUMP IN HIGH TEMPS VERSUS TODAY...AND MADE LITTLE
CHANGE TO PREVIOUS FORECAST WITH ALL AREAS RISING TO WITHIN A FEW
DEGREES EITHER SIDE OF 70. THE ONLY CAVEAT FOR THESE WARM TEMPS
WOULD BE IF ANY MORNING FOG TURNS INTO A SLOW-ERODING STRATUS
DECK THAT LINGERS WELL INTO THE DAY WITHIN THE RIDGE AXIS MAINLY
IN THE EASTERN CWA...BUT IT SEEMS UNLIKELY THAT THE SITUATION GETS
THIS PESSIMISTIC.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 345 PM CDT SUN MAY 5 2013
A PROLONGED PERIOD OF UNSETTLED WEATHER IS SHAPING UP
ACROSS THE REGION AS THE UPPER LEVEL LOW OFF THE CALIFORNIA COAST
SLOWLY PROGRESSES EASTWARD WHILE SPINNING OFF SEVERAL WEAK
DISTURBANCES AHEAD OF IT. WHILE A GENERALLY BLOCKY PATTERN WITH
RIDGING WILL EXIST ACROSS THE CENTRAL PLAINS THROUGH MUCH OF THE
PERIOD...THE LOW LEVEL FLOW WILL BEGIN TO SHIFT AND BECOME SOUTHERLY
LATE MONDAY...HELPING MOISTURE ADVECT NORTHWARD. THIS FLOW SHOULD
HELP DEWPOINTS CLIMB BACK INTO THE 50S BY TUESDAY AFTERNOON...WITH
BUILDING INSTABILITY ACROSS THE PLAINS.
WHILE INITIALLY...THERE WILL BE A SMALL CHANCE FOR SOME RAIN SHOWERS
AHEAD OF THE FIRST UPPER LEVEL WAVE SPINNING OFF THE WESTERN
LOW...INSTABILITY WILL BE VERY WEAK...AND LOW LEVEL MOISTURE WILL
STILL BE LACKING...IN ORDER TO SUPPORT MUCH IN THE WAY OF SHOWER OR
THUNDERSTORM ACTIVITY. AS A RESULT...SLOWED DOWN THE INITIAL TIMING
OF THE ONSET OF ANY PRECIPITATION TO THE PRE-DAWN HOURS TUESDAY. AS
MOISTURE CONTINUES TO SURGE NORTH DURING THE DAY TUESDAY
AFTERNOON...INSTABILITY WILL BUILD...AND SEE THE POTENTIAL FOR SOME
THUNDERSTORMS TO DEVELOP DURING THE LATE MORNING/EARLY AFTERNOON
HOURS AS STEEP LOW LEVEL LAPSE RATES WILL REQUIRE LITTLE IN THE WAY
OF FORCING FOR SHOWER AND THUNDERSTORM DEVELOPMENT. AS WE THEN
TRANSITION INTO TUESDAY NIGHT...THE NOSE OF THE LOW LEVEL JET IS
EXPECTED TO BE POINTED TOWARDS THE LOCAL AREA...WHICH SHOULD ALLOW
FOR THE DEVELOPMENT OF ELEVATED CONVECTION ACROSS THE LOCAL AREA
DURING THE LATE EVENING AND OVERNIGHT HOURS...SOME OF WHICH COULD
BECOME STRONG TO MARGINALLY SEVERE. AS A RESULT...PLAN ON
HIGHLIGHTING THE POTENTIAL FOR SOME MARGINALLY SEVERE HAIL FOR THE
TUESDAY NIGHT PERIOD IN THE AFTERNOON HWO.
BEYOND TUESDAY NIGHT...THINGS GET A LITTLE MORE MUDDLED AS MULTIPLE
WEAK DISTURBANCES AHEAD OF THE MAIN UPPER LEVEL LOW TRANSITION
ACROSS THE PLAINS. EVEN SO...THERE IS SOME AGREEMENT AMONGST THE
MODELS FOR ANOTHER DECENT SHOT OF PRECIPITATION ACROSS NORTH
CENTRAL KANSAS AND PORTIONS OF SOUTH CENTRAL NEBRASKA WEDNESDAY
NIGHT AND THURSDAY...AND SAW NO REASON TO REDUCE THE LIKELY POPS
GIVEN BY THE ALLBLEND SOLUTION FOR THIS PERIOD. THEN...DEPENDING ON
WHICH MODEL SOLUTION YOU BELIEVE...THE MAIN UPPER LEVEL LOW SHOULD
BEGIN TO TRACK EASTWARD ON FRIDAY...WITH A COLD FRONT DROPPING DOWN
ACROSS THE NORTHERN PLAINS FRIDAY NIGHT OR SATURDAY. DUE TO THE
DISCREPANCIES IN TIMING...HUNG ONTO CHANCES FOR PRECIPITATION
THROUGH SATURDAY AFTERNOON...WITH PRECIPITATION COMING TO AN END
BEHIND THIS COLD FRONT BY THE LATTER HALF OF NEXT WEEKEND. WHILE
THERE WILL BE A NOTICEABLE DROP IN TEMPERATURES BEHIND THIS
FRONT...ON THE ORDER OF 10-15F BASED ON 850MB TEMPS...DO NOT EXPECT
A RETURN TO THE CHILLY TEMPERATURES OF LATE...AS ABOVE NORMAL
TEMPERATURES ARE EXPECTED ALL WEEK...GENERALLY IN THE LOWER TO
MIDDLE 70S...WITH THIS NEXT FRONT SIMPLY DROPPING TEMPERATURES A FEW
DEGREES BELOW CLIMATOLOGY FOR EARLY/MID MAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1229 AM CDT MON MAY 6 2013
VFR CONDITIONS EXPECTED THROUGH MUCH OF THE TAF PERIOD...ALTHOUGH
IFR CONDITIONS WILL BE POSSIBLE 10-14Z.
SCATTERED MID TO HIGH LEVEL CLOUDS WILL CONTINUE AT KGRI THROUGH
THE NEXT 24 HOURS. THE PRESENCE OF A SURFACE RIDGE WILL KEEP THE
SURFACE WIND LIGHT AND VARIABLE THROUGH TONIGHT...BEFORE BECOMING
MORE ESTABLISHED FROM THE SOUTHEAST DURING THE DAY MONDAY. A
DECREASING LOW LEVEL DEWPOINT DEPRESSION...WORKING IN CONCERT WITH
THE AFOREMENTIONED LIGHT SURFACE WIND...MAY PROMOTE FOG
DEVELOPMENT AT KGRI BETWEEN 10Z AND 14Z THIS MORNING. CONFIDENCE
OF SUCH VISIBILITY RESTRICTION ACTUALLY OCCURRING IS ABOUT
50%...WITH THE SITUATION LIKELY BECOMING MORE CLEAR BETWEEN 10Z
AND 12Z. FOR NOW WILL GO WITH A PREVAILING IFR VISIBILITY AND AN
MVFR CEILING...PER GUIDANCE...10-14Z AND IF NECESSARY...UPDATE AS
WE APPROACH SUNRISE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...SAR
AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
314 AM EDT MON MAY 6 2013
.SYNOPSIS...
A VERY SLOW MOVING STORM SYSTEM WILL BRING SOME RAIN TODAY AND
THEN MORE SCATTERED SHOWERY WEATHER ON TUESDAY. A LATE WEEK WARMUP
WILL PRECEDE A COLD FRONT THAT MAY ARRIVE ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM MONDAY...SHOWERS WERE ONGOING ACROSS THE FORECAST AREA
THIS MORNING. COVERAGE WAS NUMEROUS. A LARGE BATCH OF SHOWERS AND
THUNDERSTORMS WAS OFFSHORE IN ASSOCIATION WITH AN AREA OF LOW
PRESSURE. A COASTAL TROUGH LIED RIGHT ALONG THE IMMEDIATE COAST. AN
OCCLUDED FRONT WAS JUST UPSTREAM OF THE PEE DEE.
THE OCCLUDED FRONT WILL MOVE FROM SW TO NE ACROSS THE FORECAST
AREA...LASTLY ACROSS THE CAPE FEAR AREA DURING THE EVE. MUCH DRIER
AIR WILL MOVE INTO THE AREA BEHIND THIS FRONT.
WILL MAINTAIN HIGH POPS...GENERALLY LIKELY TO CATEGORICAL...UNTIL
THIS BOUNDARY LIFTS OUT AND AWAY FROM THE AREA. WILL CONTINUE TO
CHARACTERIZE THE PRECIPITATION AS SHOWERS...SOME OF WHICH COULD
PRODUCE HEAVY DOWNPOURS FROM TIME TO TIME. ADDITIONAL RAINFALL
AMOUNTS OF ONE-HALF TO THREE-QUARTERS OF AN INCH ARE EXPECTED BEFORE
THE SHOWERS SHUT OFF.
POPS WILL BE TRENDING LOWER THIS MORNING ACROSS OUR SOUTHWEST ZONES
AND WILL NOT CARRY MENTION OF SHOWERS THERE THIS AFTERNOON.
HOWEVER...ACROSS THE REMAINDER OF THE AREA...ALTHOUGH POPS WILL BE
TRENDING LOWER...DO EXPECT ISOLATED TO SCATTERED SHOWERS TO REMAIN
IN THE PICTURE...EVEN THIS AFTERNOON...ALONG AND N OF A LINE FROM
UDG TO CRE WHERE THE DEEPER MOISTURE WILL HANG ON LONGEST.
ALSO WATCHING SOME STRATUS AND FOG THAT HAS DEVELOPED TO OUR SOUTH
WHICH MAY ADVECT INTO OUR SOUTHERN ZONES FOR A TIME THIS MORNING...
BEFORE THE ARRIVAL OF DRIER AIR HELPS IN THE DISSIPATION PROCESS.
A BROAD AND SLOW MOVING...VERTICALLY STACKED AREA OF LOW PRESSURE...
CENTERED ACROSS THE TENNESSEE VALLEY THIS MORNING...WILL CONTINUE TO
DRIFT TOWARD THE EASTERN CAROLINAS WITH THE EASTERN FRINGES OF THIS
FEATURE BEGINNING TO MOVE INTO THE AREA TONIGHT. WILL REINTRODUCE
POPS INTO SW AND W AREAS TONIGHT WHILE ANY RESIDUAL SHOWERS
ASSOCIATED WITH THE OCCLUDED FRONT LIFT N AND NE OF THE AREA.
CLOUD COVER WILL TEND TO THIN LATER THIS MORNING AND THROUGH THE
AFTERNOON...ESPECIALLY ACROSS S AND SW AREAS WHERE CONSIDERABLE
BREAKS OF SUNSHINE SHOULD DEVELOP. THIS WILL ALLOW TEMPS TO REACH
THE LOWER TO MID 70S...HIGHEST ACROSS PORTIONS OF THE PEE DEE...
AND COOLEST N OF A LBT TO ILM LINE...WHERE CLOUDS WILL REMAIN
THICKEST LONGEST. ALSO TEMPS WILL BE HELD DOWN THIS AFTERNOON ALONG
THE COAST...ESPECIALLY ACROSS COASTAL BRUNSWICK AND SOUTHERN NEW
HANOVER COUNTIES DUE TO AN ONSHORE WIND.
COOLER AIR WILL BE ARRIVING IN ASSOCIATION WITH THE UPPER LOW
TONIGHT...FIRST ACROSS WESTERN ZONES. CLOUDS SHOULD BE ON THE
INCREASE AS THIS FEATURE DRAWS VERY SLOWLY CLOSER. STILL...TEMPS
WILL BE CONSIDERABLY COOLER THAN SUN NIGHT...WITH LOWS EXPECTED TO
REACH THE LOWER TO MID 50S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...CLIMATOLOGICALLY UNUSUAL UPPER LEVEL CUTOFF AND
COLD POOL OVER THE AREA ON TUESDAY MAKING FOR A TRICKY FORECAST. THE
MAIN AXIS OF DEEP MOISTURE AND LIFT WILL HAVE ALREADY LIFTED TO THE
NORTH BY THE START OF THE PERIOD. THE SYNOPTIC SCALE DRYSLOT WILL
ALSO HAVE PUSHED THROUGH IN THE LOWER LEVELS BUT THE SWIRLING MASS
OF MID LEVEL MOISTURE AND COLD AIR WILL STILL BE OVERHEAD. TUESDAY
THUS SHAPING UP TO BE VARIABLY CLOUDY WITH POCKETS OF SUN LEADING TO
STEEP LL LAPSE RATES AND CU FIELDS. THESE CONVECTIVE ELEMENTS WILL
HAVE SOME MID LEVEL INSTABILITY TO GROW INTO SHOWERS WITH EVEN A FEW
RUMBLES OF THUNDER. HOWEVER THE SUBCLOUD LAYER IS FORECAST TO BE
VERY DRY. COVERAGE THUS CAPPED AT SCT/CHC RANGE. BREAKS IN CLOUDS
SHOULD BE COMMON ENOUGH IN MOST PLACES FOR LOW 70S FOR A HIGH.
WHATEVER EXTENT SHOWER ACTIVITY MANAGES TO MANIFEST WILL ALL BE GONE
BY SUNSET. WRAPAROUND MOISTURE WILL MEAN CLOUDS SLOW TO DECREASE
TUESDAY NIGHT AND EARLY WEDNESDAY BUT A MORE RAPID DRYING TREND
SLATED FOR LATER WED AFTERNOON. THIS WILL MANAGE TO BOLSTER HIGHS A
FEW DEGREES TO MID / UPPER 70S N TO S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 3 AM MONDAY...MUCH OF THE LONG TERM WILL BRING A RETURN OF
CLIMATOLOGICAL TEMPERATURES. THE EXIT OF THE LOW PRESSURE SYSTEM OF
THE SHORT TERM WILL ALLOW FOR A LOW AMPLITUDE RIDGE TO BUILD OVER
THE SOUTHEASTERN U.S. SURFACE PRESSURE PATTERN WILL BE RATHER WEAK
WHICH SHOULD PREVENT ADEQUATE MOISTURE TO SUPPORT ANY MEANINGFUL
PRECIP CHANCES EVEN AS AFTERNOON SEA BREEZE DEVELOPS EACH DAY.
FRIDAY INTO SATURDAY A DEEP TROUGH WILL BE GETTING CARVED INTO THE
GREAT LAKES REGION. LEADING EDGE OF THIS SYSTEM WILL BE A FAIRLY
SHARP COLD FRONT. THIS MAY BE DUE THIS FAR SOUTH ON SUNDAY. MOISTURE
FLUX MAY OCCUR LONG ENOUGH SAT INTO SUNDAY FOR SUFFICIENT MOISTENING
FOR GOOD RAIN CHANCES ONCE THE FRONT ARRIVES.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...TRICKY FORECAST CONTINUES AS UNSETTLED WEATHER BRINGS
PERIODS OF MVFR AND IFR DUE TO VARYING LOW CIGS...AREAS OF FOG...AND
RAIN SHOWERS...ESPECIALLY THROUGH THIS MORNING. OTHERWISE EXPECT VFR.
VARYING CEILINGS AND VISIBILITIES IN SHOWERS AND BR THROUGH THIS
MORNING. CONFIDENCE IS A BIT LOW GIVEN THE VARYING RAINFALL RATES.
ALSO SOME CONCERN THAT FOG WILL ADVECT INTO PORTIONS OF THE AREA
FROM THE SOUTH AS DEWPOINTS CONTINUE TO CLIMB INTO THE 60S.
PERIODS OF HEAVIER RAINFALL WILL LIKELY CREATE BRIEF PERIODS OF IFR.
AS DRIER AIR REACHES THE AREA LATER THIS MORNING AND THROUGH THE
AFTERNOON...EXPECT VFR CONDITIONS TO DEVELOP AS CEILINGS AND LOWER
VISIBILITIES IMPROVE AND THE RISK FOR SHOWERS DIMINISHES.
SOUTHEAST WINDS AOB 12 KTS WILL GRADUALLY BECOME SOUTH IN THE
AFTERNOON.
TOWARDS THE END OF THE PERIOD...LIGHT WINDS AND VFR WILL PREVAIL.
EXTENDED OUTLOOK...AN UPPER LOW WILL MOVE OVER THE AREA TUESDAY WITH
SHOWERS AND ISOLATED THUNDERSTORMS IN THE AFTERNOON AND EVENING.
SMALL HAIL WILL BE POSSIBLE WITH UNUSUALLY LOW FREEZING LEVELS. AN
ISOLATED SHOWER IS POSSIBLE WEDNESDAY AFTERNOON.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1115 PM SUNDAY...LATEST SFC PRESSURE PATTERN AND GRADIENT
AHEAD OF THE APPROACHING BOUNDARY FROM THE SOUTH...CONTINUE TO
SUPPORT EAST TO SOUTHEAST 15 TO 25 KT WINDS...WITH FEW GUSTS UP TO
30 KT. CURRENTLY THIS FRONT IS IN THE VICINITY OF CAPE ROMAIN
SC...VIA LATEST SFC OBS. HRRR MODEL DATA SUPPORTS ITS SLOW
PROGRESSION NORTHWARD OVERNIGHT INTO MONDAY. THE ILM SC WATERS WILL
LIKELY SEE WINDS VEERING TO THE S OR SSW 10 TO 15 KT AFTER ITS
PASSAGE DURING THE PRE-DAWN HRS OF MONDAY. IT MAY TAKE UP TO THE
EARLY AFTERNOON HOURS OF MONDAY BEFORE PUSHING ACROSS AND NORTH
OF THE ILM NC WATERS...THIS BASED ON LATEST NAM AND GFS MODEL
OUTPUT.
SIGNIFICANT SEAS WILL CONTINUE TO BE DOMINATED BY A PSEUDO NE-E
DIRECTION SWELL AT 7 TO 8 SECOND DOMINANT PERIODS. OVERALL...SIG
SEAS WILL RANGE BETWEEN 4 AND 8 FT...HIGHEST OUTER WATERS OFF CAPE
FEAR AND WINYAH BAY...AND LOWEST SOUTH OF CAPE FEAR TO LITTLE
RIVER INLET. AS WINDS SUBSIDE AFTER THE PASSAGE OF THE FRONTAL
BOUNDARY...THE IMMEDIATE WIND DRIVEN WAVES WILL BEGIN TO SUBSIDE.
HOWEVER...WAVEWATCH3 INDICATES A NE 10-11 SECOND PERIOD SWELL TO
LITERALLY OCCUPY A LARGE CHUNK OF THE NORTH ATLANTIC BASIN.
LATEST WAVEWATCH3 DOES INDICATE A SLOWER SUBSIDING TREND...WHEREAS
THE LOCALLY PRODUCED SWAN IS A BIT TOO QUICK. PREFER THE SLOWER
TREND. AS A RESULT...HAVE CONTINUED THE SCA MAINLY FOR SIG SEAS
THRU MIDDAY MONDAY ACROSS THE ILM SC WATERS...AND LATE AFTERNOON
MONDAY FOR THE ILM NC WATERS. OVERALL...AVERAGE PERIODS WILL RUN
5.5 SECONDS.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...WITH SUCH A CIRCULAR LOW BOTH AT THE SURFACE AND
ALOFT MOVING OVER THE REGION WINDS WILL BE QUITE LIGHT ON TUESDAY
BUT ALSO SHOW CONSIDERABLE VARIATION IN DIRECTION ESPECIALLY EARLY.
AS THE LOW PULLS AWAY LATE IN THE DAY A PREDOMINANT SW FLOW MAY GET
ESTABLISHED. THE EXIT OF THE SYSTEM TO THE NORTHEAST WILL BE SO
GRADUAL THAT SW WINDS WILL PERSIST TROUGH THE PERIOD. A SLIGHTLY
HIGHER WIND SPEED WILL BE EXPERIENCED ON WEDNESDAY AS THE EXIT OF
THE SURFACE WAVE ALLOWS FOR A SLIGHTLY STRONGER GRADIENT ACROSS THE
WATERS. IN THE ABSENCE OF ANY SWELL ENERGY SEAS WILL BE
PREDOMINANTLY WIND WAVES THROUGH THE PERIOD. AS SUCH DOMINANT WAVE
HEIGHT WILL BE CAPPED AT 3 FT THROUGH THE SHORT TERM.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 AM MONDAY...QUIET MARINE CONDITIONS EXPECTED FOR THE LONG
TERM PERIOD. THE SURFACE PRESSURE PATTERN WILL BE RATHER POORLY
DEFINED FOR MOST OF IT AS THE NEAREST `PLAYER` WILL BE WEAK HIGH
PRESSURE IN THE ATLANTIC BUT NOT NEAR BERMUDA AS IT OFTEN THE CASE
BUT MUCH REMOVED FURTHER EASTWARD. SEAS ON THE ORDER OF 2 TO 3 FT
WILL BE COMPRISED OF A 5 SECOND WIND CHOP AND A 7-8 SECOND WEAK SE
SWELL.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR AMZ254-256.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR AMZ250-
252.
&&
$$
SYNOPSIS...MBB
NEAR TERM...RJD
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...RJD/SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
158 AM EDT MON MAY 6 2013
.SYNOPSIS...
A SLOW MOVING AND COMPLEX STORM SYSTEM WILL CROSS THE CAROLINAS
OVER THE NEXT FEW DAYS. SHOWERS AND ISOLATED THUNDERSTORMS WILL BE
POSSIBLE INTO MONDAY MORNING...THEN AGAIN ON TUESDAY. WIDESPREAD
RAINFALL IS EXPECTED. WEAK HIGH PRESSURE WILL SLOWLY FILL IN BEHIND
THE DEPARTING STORM WEDNESDAY AND THURSDAY. MUCH WARMER TEMPERATURES
ARE EXPECTED LATE IN THE WEEK AS THE REGION DRIES OUT.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 11 PM SUNDAY...MAIN FOCUS OF THIS UPDATE REMAINS WITH
THE REDISTRIBUTION OF OVERNIGHT POPS. FOR LATE THIS EVENING...
BASICALLY TOOK THE CURRENT 88D MOSAIC AND EXTRAPOLATED THE
MOVEMENT FOR THE NEXT 3 HRS. AFTERWARD...THE LATEST NAM AND HRRR
MODELS WERE UTILIZED FOR THE REMAINDER OF THE PRE-DAWN HOURS. IN
ESSENCE...THE MAIN CONVEYOR BELT OF PCPN OVER THE ATL WATERS...IS
CURRENTLY AND SLOWLY LIFTING NE WARD. THE PCPN WITHIN THIS BELT
IS MOVING FROM SSE TO NNW...AND PUSHING ONSHORE. AFTER THE
PCPN MOVES ONSHORE...ITS AREAL COVERAGE DECREASES FROM
WIDESPREAD/AREAS OVER THE ADJACENT ATL WATERS TO SCATTERED OVER LAND
AREAS. OF NOTE...DRIER AIR...VIA LATEST WATER VAPOR LOOPS...IS
PARTIALLY FILTERING IN FROM THE SOUTH AND LIKELY HAVING SOME INPUT
FOR WHY PCPN IS NOT AS WIDESPREAD AND/OR INTENSE OVER LAND. IN
GENERAL WILL INDICATE CATEGORICAL POPS CLOSER TO THE
COAST...SLIGHTLY DROPPING THE FURTHER INLAND ONE GOES. QPF HAS ALSO
BEEN FURTHER TWEAKED TO ACCOUNT FOR THE LACK OF WIDESPREAD/ INTENSE
PCPN COVERAGE. LATEST MIN TEMPS WERE TWEAKED TO THE HIER SIDE OF
GUIDANCE WITH AROUND 60 INLAND...TO 60-65 AT THE COAST. HOURLY SFC
DEWPOINTS WILL MIMIC HOURLY TEMPS...EXCEPT LOWER BY 1 TO 3 DEGREES
DUE TO THE INFLUX OF MOISTURE AND MILD TEMPS UNDER THE E TO SE FLOW.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...AN OCCLUDED FRONT BENT BACK TO THE NORTHWEST
WILL SWING THROUGH THE EASTERN CAROLINAS MONDAY MORNING
ACCOMPANIED BY A BAND OF MODERATE OR POSSIBLY HEAVY SHOWERS. FOR
EASTERN SC THE BULK OF THE RAIN SHOULD BE DONE BY SUNRISE...BUT IT
WILL PROBABLY TAKE AT LEAST A FEW MORE HOURS FOR RAIN TO CLEAR
ELIZABETHTOWN AND BURGAW. BEHIND THIS FRONT A DRIER AIRMASS WILL
BUILD IN DURING THE DAY ON SOUTH WINDS. (YES...IT HAS BEEN THAT
KIND OF SPRING) THE MONSTER UPPER LOW THAT HAS MOVED ACROSS THE
SOUTHEAST THE PAST COUPLE OF DAYS WILL DRAW NEAR ENOUGH TO THE
REGION DURING THE AFTERNOON TO STEEPEN LAPSE RATES FROM 750 MB UP
THROUGH THE TROPOPAUSE. EVEN WITH LIMITED MOISTURE...WARMING
DAYTIME TEMPERATURES COULD PRODUCE A FEW POP-UP SHOWERS...ENOUGH
TO WARRANT A SMALL POP DURING THE AFTERNOON.
PARTLY CLOUDY TO MOSTLY CLEAR SKIES MONDAY EVENING AND LIGHT WINDS
WILL ALLOW TEMPERATURES TO FALL SURPRISINGLY FAST AND LOWS SHOULD
REACH 50-55 BY 3 AM. CLOUDS SHOULD INCREASE LATE MONDAY NIGHT AS
THE CIRCULATION OF THE UPPER LOW MOVES ACROSS SOUTH CAROLINA AND
WE COULD HAVE SHOWERS REDEVELOPING BY DAYBREAK TUESDAY...
ESPECIALLY ACROSS THE SC PEE DEE REGION.
TUESDAY WILL BE A VERY INTERESTING DAY METEOROLOGICALLY. VERY COLD
MID AND UPPER LEVEL TEMPERATURES FOR THE SEASON WILL PUSH
OVERHEAD DURING THE PEAK OF SOLAR HEATING. FREEZING LEVELS WILL
PLUNGE TO ONLY 8000 FEET...700 MB TEMPS FALL TO -4C...AND 500 MB
TEMPS SHOULD GO AS LOW AS -22C. MODEL FORECAST SOUNDINGS HAVE
CONVECTIVE TEMPERATURES AS LOW AS 63-67 DEGREES...SEVERAL DEGREES
BELOW MY FORECAST HIGHS. THE LIMITING FACTORS WILL BE SUNSHINE AND
LOW LEVEL MOISTURE AS SURFACE DEWPOINTS WILL HOLD IN THE 49-53
RANGE. EVEN GIVEN THESE LIMITATIONS I ANTICIPATE WIDESPREAD
TOWERING CUMULUS DEVELOPMENT WITH 50-70 PERCENT COVERAGE OF
SHOWERS DURING THE DAY. RELATIVELY WEAK UPDRAFT STRENGTH (LIFTED
INDEX NO GREATER THAN -2 AT ANY PRESSURE LEVEL) AND NO STORM
ORGANIZATION (0-6 KM BULK SHEAR <20 KT) SHOULD PRECLUDE LARGE
HAIL...BUT SMALL HAIL IS POSSIBLE GIVEN THE HIGH PROPORTION OF CAPE
WITHIN THE -10C TO -30C REGION AND THE SMALL DISTANCE BETWEEN THE
ENVIRONMENTAL FREEZING LEVEL AND THE GROUND.
THE ATMOSPHERE SHOULD STABILIZE TUESDAY NIGHT AS THE UPPER LOW
DRIFTS JUST NORTH OF THE REGION. A FEW LINGERING SHOWERS MAY CARRY
ON INTO THE EVENING HOURS BUT THE TREND SHOULD BE FOR DRYING
CONDITIONS WITH LOWS IN THE LOWER 50S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 3 PM SUNDAY...TIGHTLY WOUND LOW PRESSURE SYSTEM WILL
CONTINUE TO MOVE NORTHEAST THROUGH THE CAROLINAS TOWARD THE MID
ATLANTIC COAST WED THROUGH THURS. THE H5 LOW WILL TRACK UP THROUGH
NC INTO VA ON WED. SOME MOISTURE WILL CONTINUE TO WRAP AROUND THE
SYSTEM INTO THE AREA BUT IT LOOKS LIKE BEST MID TO UPPER SUPPORT
WILL LIE TO THE NORTH. CHANCE OF PCP WILL LINGER THROUGH WED BUT
THURS AND FRI LOOK DRIER AS SUBSIDENCE INCREASES ON THE BACK END OF
SYSTEM IN A DEEP W-NW FLOW. THIS DOWNSLOPE FLOW WILL PROMOTE DRIER
WEATHER FOR THURS AND FRI BUT WILL ALSO HELP TO BOOST UP THE TEMPS
BACK TO NORMAL. MID TO UPPER RIDGE WILL BUILD UP THROUGH THE
SOUTHEAST WITH H5 HEIGHT RISES UP TO 580 DM...INCREASING A LITTLE
FURTHER THROUGH SAT BEFORE DEEP MID TO UPPER TROUGH PUSHES EAST BY
THE END OF THE WEEKEND. THIS DEEP MID TO UPPER TROUGH WILL PUSH A
COLD FRONT EAST INTO THE CAROLINAS BY EARLY NEXT WEEK. A DEEP MOIST
RETURN FLOW WILL SET UP AHEAD OF THE FRONT THROUGH THE END OF THE
WEEKEND...INCREASING THE CHC OF SHWRS AND TSTMS. TEMPS IN THE MID
70S ON WED WILL SURPASS THE 80 MARK BY THURS AND WILL REMAIN WARM
THROUGH THE WEEKEND.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...TRICKY FORECAST CONTINUES AS UNSETTLED WEATHER BRINGS
PERIODS OF MVFR AND IFR DUE TO VARYING LOW CIGS...AREAS OF FOG...AND
RAIN SHOWERS...ESPECIALLY THROUGH THIS MORNING. OTHERWISE EXPECT VFR.
VARYING CEILINGS AND VISIBILITIES IN SHOWERS AND BR THROUGH THIS
MORNING. CONFIDENCE IS A BIT LOW GIVEN THE VARYING RAINFALL RATES.
ALSO SOME CONCERN THAT FOG WILL ADVECT INTO PORTIONS OF THE AREA
FROM THE SOUTH AS DEWPOINTS CONTINUE TO CLIMB INTO THE 60S.
PERIODS OF HEAVIER RAINFALL WILL LIKELY CREATE BRIEF PERIODS OF IFR.
AS DRIER AIR REACHES THE AREA LATER THIS MORNING AND THROUGH THE
AFTERNOON...EXPECT VFR CONDITIONS TO DEVELOP AS CEILINGS AND LOWER
VISIBILITIES IMPROVE AND THE RISK FOR SHOWERS DIMINISHES.
SOUTHEAST WINDS AOB 12 KTS WILL GRADUALLY BECOME SOUTH IN THE
AFTERNOON.
TOWARDS THE END OF THE PERIOD...LIGHT WINDS AND VFR WILL PREVAIL.
EXTENDED OUTLOOK...AN UPPER LOW WILL MOVE OVER THE AREA TUESDAY WITH
SHOWERS AND ISOLATED THUNDERSTORMS IN THE AFTERNOON AND EVENING.
SMALL HAIL WILL BE POSSIBLE WITH UNUSUALLY LOW FREEZING LEVELS. AN
ISOLATED SHOWER IS POSSIBLE WEDNESDAY AFTERNOON.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1115 PM SUNDAY...LATEST SFC PRESSURE PATTERN AND GRADIENT
AHEAD OF THE APPROACHING BOUNDARY FROM THE SOUTH...CONTINUE TO
SUPPORT EAST TO SOUTHEAST 15 TO 25 KT WINDS...WITH FEW GUSTS UP TO
30 KT. CURRENTLY THIS FRONT IS IN THE VICINITY OF CAPE ROMAIN
SC...VIA LATEST SFC OBS. HRRR MODEL DATA SUPPORTS ITS SLOW
PROGRESSION NORTHWARD OVERNIGHT INTO MONDAY. THE ILM SC WATERS WILL
LIKELY SEE WINDS VEERING TO THE S OR SSW 10 TO 15 KT AFTER ITS
PASSAGE DURING THE PRE-DAWN HRS OF MONDAY. IT MAY TAKE UP TO THE
EARLY AFTERNOON HOURS OF MONDAY BEFORE PUSHING ACROSS AND NORTH
OF THE ILM NC WATERS...THIS BASED ON LATEST NAM AND GFS MODEL
OUTPUT.
SIGNIFICANT SEAS WILL CONTINUE TO BE DOMINATED BY A PSEUDO NE-E
DIRECTION SWELL AT 7 TO 8 SECOND DOMINANT PERIODS. OVERALL...SIG
SEAS WILL RANGE BETWEEN 4 AND 8 FT...HIGHEST OUTER WATERS OFF CAPE
FEAR AND WINYAH BAY...AND LOWEST SOUTH OF CAPE FEAR TO LITTLE
RIVER INLET. AS WINDS SUBSIDE AFTER THE PASSAGE OF THE FRONTAL
BOUNDARY...THE IMMEDIATE WIND DRIVEN WAVES WILL BEGIN TO SUBSIDE.
HOWEVER...WAVEWATCH3 INDICATES A NE 10-11 SECOND PERIOD SWELL TO
LITERALLY OCCUPY A LARGE CHUNK OF THE NORTH ATLANTIC BASIN.
LATEST WAVEWATCH3 DOES INDICATE A SLOWER SUBSIDING TREND...WHEREAS
THE LOCALLY PRODUCED SWAN IS A BIT TOO QUICK. PREFER THE SLOWER
TREND. AS A RESULT...HAVE CONTINUED THE SCA MAINLY FOR SIG SEAS
THRU MIDDAY MONDAY ACROSS THE ILM SC WATERS...AND LATE AFTERNOON
MONDAY FOR THE ILM NC WATERS. OVERALL...AVERAGE PERIODS WILL RUN
5.5 SECONDS.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...A NORTHEASTWARD MOVING OCCLUDED FRONT WILL
SWEEP THROUGH THE AREA MONDAY MORNING. THIS IS VERY
UNCHARACTERISTIC OF TYPICAL MAY WEATHER...BUT SEEMS TO BE PAR FOR
THE COURSE FOR THIS SPRING. THE LAST OF THE STRONG EASTERLY WINDS
WE HAVE EXPERIENCED ALL WEEKEND WILL ABATE AS THE FRONT CROSSES
THE AREA. MONDAY AFTERNOON THROUGH TUESDAY NIGHT WILL SEE MUCH
LIGHTER WIND SPEEDS WITHIN THE BAGGY PRESSURE PATTERN AROUND BROAD
LOW PRESSURE OVER THE CAROLINAS. THIS LOW IS ACTUALLY A SURFACE
REFLECTION OF A MUCH MORE POTENT LOW IN THE MID AND UPPER LEVELS
OF THE ATMOSPHERE WHICH SHOULD CREATE SHOWERY AND PERHAPS THUNDERY
WEATHER AGAIN TUESDAY.
THE SMALL CRAFT ADVISORY SHOULD BE ABLE TO DROP FOR THE NC WATERS
EARLY MONDAY AFTERNOON AS LIGHTER WIND SPEEDS WILL NOT SUSTAIN
SEAS AT OR ABOVE 6 FEET. OUTSIDE OF MONDAY MORNING...SEAS SHOULD
BE DOMINATED BY 8 TO 10 SECOND EAST AND SOUTHEAST SWELL...WITH 2-4
FT HEIGHTS.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 3 PM SUNDAY...TIGHTLY WOUND LOW PRESSURE SYSTEM WILL TRACK
UP FROM NORTH CAROLINA INTO THE MID ATLANTIC COAST WED INTO THURS.
AS LOW LIFTS OFF FARTHER TO THE NE THROUGH THURSDAY...THE WINDS WILL
SHIFT AROUND FROM SW TO W WED INTO THURS. WINDS WILL BACK TO THE SW
LATE THURS AS WEAK HIGH PRESSURE BUILDS IN AND WILL SEE INCREASING
RETURN FLOW OUT OF THE SOUTH TO SOUTHWEST AS HIGH SHIFTS OFF SHORE
HEADING INTO THE WEEKEND. WINDS WILL GENERALLY REMAIN AROUND 10 KTS
OR LESS THROUGH THE PERIOD. SEAS WILL GENERALLY STAY IN THE 2 TO 4
FT RANGE WITH A LOWERING TREND OF SEAS THROUGH MID WEEK IN THE OFF
SHORE FLOW AND THEN A REVERSE TREND BY THE WEEKEND IN INCREASING
SOUTHERLY PUSH.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT MONDAY FOR AMZ254-256.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT MONDAY FOR AMZ250-252.
&&
$$
NEAR TERM...DCH
SHORT TERM...TRA
LONG TERM...RGZ
AVIATION...SGL/RJD
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1130 PM CDT SUN MAY 5 2013
.UPDATE...FOR 06Z AVIATION FORECAST
.AVIATION...
UPPER LOW CENTERED OVER NORTHEAST ALABAMA AT 04Z WILL ROTATE UP
INTO TENNESSEE AND THEN BACK DOWN INTO NORTHWEST GEORGIA OVER THE
NEXT 24 HOURS. THIS WILL KEEP THE WEATHER UNSETTLED FOR AVIATION
INTERESTS WITH LOW CEILINGS IN THE IFR RANGE AT TIMES ALONG WITH
MORE SHOWER ACTIVITY ROTATING AROUND THE UPPER LOW. BY TUESDAY
UPPER LOW FINALLY WORKS INTO THE CAROLINAS AS KICKER LOW DROPS
INTO SOUTHERN CALIFORNIA. CAROLINA LOW FINALLY PHASES WITH BROAD
UPPER TROUGH UP IN CANADA ON THURSDAY AND LIFTS OUT THROUGH THE
NORTHEAST.
BOYD
&&
.PREV DISCUSSION... /ISSUED 833 PM CDT SUN MAY 5 2013/
UPDATE...
SATELLITE IMAGERY SHOWS CENTER OF UPPER LEVEL LOW OVER NORTHERN
ALABAMA...WHILE RADAR IMAGERY SHOWS BANDS OF RAIN AND A FEW
THUNDERSTORMS CONTINUE TO THE NORTH OF THE CIRCULATION ACROSS
THE SOUTHERN AND EASTERN CWA. HAVE SEEN SEVERAL LIGHTNING STRIKES
AND REPORTS OF PEA SIZE HAIL WITH SOME OF THE STRONGER CONVECTIVE
CORES...AND CANNOT RULE OUT SOME ADDITIONAL STRIKES OR HAIL FOR A
FEW HOURS UNTIL INSTABILITY WANES OVERNIGHT. AFTERNOON HRRR MODEL
RUNS INDICATES UPPER LOW WILL BE MAKING A CYCLOIDAL LOOP OVER THE
NEXT 24 HOURS...MOVING EASTWARD INTO NORTHERN GEORGIA TONIGHT AND
INTO EASTERN TENNESSEE BY SUNRISE...THEN BACK WESTWARD INTO THE
MID STATE TOMORROW BEFORE RETURNING INTO NORTHERN GEORGIA MONDAY
NIGHT. AS THE FIRST PART OF THIS LOOP OCCURS TONIGHT...RAIN
ACROSS SOUTHEASTERN MID TN WILL PIVOT NORTHWESTWARD AROUND THE
CIRCULATION WHICH SHOULD BRING RAIN INTO AT LEAST THE SOUTHEASTERN
PARTS OF THE NASHVILLE METRO...WITH RAIN ALSO SPREADING ACROSS THE
UPPER CUMBERLAND REGION AND PLATEAU THROUGH THE NIGHT. WESTERN
ZONES LOOK TO STAY MOSTLY DRY WITH JUST A FEW SHOWERS. HAVE
UPDATED GRIDS/ZONES MAINLY TO ADJUST TEMPS/POPS BASED ON LATEST
OBS AND ADD MENTION OF THUNDER.
SHAMBURGER
PREV DISCUSSION... /ISSUED 643 PM CDT SUN MAY 5 2013/
UPDATE...FOR 00Z AVIATION FORECAST
AVIATION...
SEEMS LIKE I`VE BEEN MENTIONING THIS PESKY UPPER LOW FOR DAYS.
WELL...IT`S NOW OVER NORTH ALABAMA WITH COLD CORE TEMPS DOWN TO
-25 CELSIUS AT 500 MBARS. BANDS OF SHOWERS AND ISOLATED
THUNDERSTORMS CONTINUE TO ROTATE AROUND THE CENTER AND WILL WORK
NORTHWEST TOWARD NASHVILLE THIS EVENING. LOOK FOR POOR FLYING
CONDITIONS TO REDEVELOP THIS EVENING AND OVERNIGHT. UPPER LOW
CURRENTLY HITTING WEST COAST WILL EVENTUALLY KICK PESKY UPPER LOW
EASTWARD AND INTO THE CAROLINAS BUT NOT BEFORE TUESDAY. THIS
BASICALLY MEANS AN UNSETTLED PERIOD OF WEATHER FOR THE MID STATE.
BOYD
PREV DISCUSSION... /ISSUED 445 PM CDT SUN MAY 5 2013/
UPDATE...
HAVE UPDATED THE GRIDS/ZONES TO ADD A CHANCE OF THUNDERSTORMS TO
SOUTHERN AREAS INTO THE EVENIGN AS AN ARC OF SCATTERED
THUNDERSTORMS MOVES NORTHWEST INTO THE CWA. OTHER MORE WIDELY
SCATTERED SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL DEVELOP
FURTHER NORTHWARD AS WELL BENEATH COLD AIR ALOFT ASSOCIATED WITH
UPPER LEVEL LOW OVER NORTHERN ALABAMA. A FEW OF THE STORMS WILL BE
CAPABLE OF SMALL HAIL AND SOME GUSTY WINDS. REST OF FORECAST IS
UNCHANGED.
SHAMBURGER
PREV DISCUSSION... /ISSUED 315 PM CDT SUN MAY 5 2013/
DISCUSSION...
UPPER LOW MOVING SLOWLY EASTWARD ACROSS NRN AL. THIS FEATURE...ALONG
WITH THE ASSOCIATED SURFACE TROUGH...IS EXPECTED TO SLOW DOWN AND
POSSIBLY MEANDER TOWARD AND OVER THE MID STATE BY MONDAY AFTERNOON.
IT IS THEN EXPECTED TO MOVE EASTWARD ACROSS THE CAROLINAS ON
TUESDAY. AS A RESULT...OFF AND ON SHOWER ACTIVITY TO CONTINUE
THROUGH MONDAY. UPCOMING QPF AMOUNTS DO NOT LOOK THREATENING WITH
GENERALLY LESS THAN ONE HALF INCH EXPECTED THROUGH MONDAY. A BREAK
FROM THE SHOWER ACTIVITY IS EXPECTED ON TUESDAY.
FOR THE NEAR TERM POPS...GENERALLY 60-70% POPS SHOULD COVER IT
TONIGHT AND MONDAY. FOR THE NEAR TERM TEMPS...WARMING TREND EXPECTED
WITH HIGHS NEAR 70 ON TUESDAY AS MORE IN THE WAY OF SUNSHINE
RETURNS.
IN THE EXT FCST...AS THE PREVIOUSLY MENTIONED UPPER LOW
DEPARTS...UPPER RIDGING AND WARMER WEATHER WILL OCCUR. ONCE THE
RIDGE AXIS REACHES AND MOVES EAST OF MIDDLE TN BY THU NT...SHOWER
AND TSTM CHANCES WILL BE ON THE INCREASE. NEXT FROPA LOOKS LIKE SAT
NT. THUS...HIGHEST POPS OF AROUND 50% OR SO WILL BE FOR THE SAT AND
SUN PERIODS.
AS FOR THE EXT TEMPS...WE`LL SEE ABOVE NORMAL WARMTH THROUGH THE
BULK OF THE PERIOD. HIGHS WILL REACH THE UPPER 70S-LOWER 80S FOR
THU-SAT. COOLER SUNDAY.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1145 PM CDT SUN MAY 5 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 230 PM CDT SUN MAY 5 2013
MAIN FORECAST CONCERN IS ON ANY FOG POTENTIAL TONIGHT
CURRENTLY AS OF 19Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED UPPER HIGHS IN SOUTHERN BRITISH COLUMBIA AND OVER THE GREAT
LAKES REGIONS...WHILE UPPER LOWS WERE PRESENT JUST WEST OF SAN
FRANSISCO CA...OVER CENTRAL SOUTH DAKOTA AND OVER ALABAMA. THIS
SETUP RESULTS IN LITTLE FLOW IN THE UPPER LEVELS ACROSS THE NORTHERN
U.S.. THERE REMAINS SCATTERED-BROKEN HIGH CLOUDS OVER THE AREA...ON
THE SOUTHWEST SIDE OF THE UPPER HIGH. OTHERWISE...A DRY AIRMASS HAS
BEEN ADVECTING INTO THE FORECAST AREA FROM THE EAST...WITH THE 12Z
GRB SOUNDING REFLECTIVE OF THE DRY AIR. THE COMBINATION OF THE DRY
AIR...850MB TEMPS AROUND 8C...AND THE SUN HAS ALLOWED TEMPERATURES
TO CLIMB INTO THE 65 TO 75 DEGREE RANGE WHERE SNOW DOES NOT EXIST.
MEANWHILE...DODGE CENTER WHICH STILL HAS A DECENT AMOUNT OF SNOW ON
THE GROUND...TEMPERATURES ARE STUCK IN THE MID 40S. REGARDING THE
SEA LEVEL PRESSURE PATTERN...HIGH PRESSURE STRETCHED ACROSS NORTHERN
MINNESOTA INTO NORTHERN ONTARIO...WHILE AN INVERTED TROUGH WAS
PRESENT OVER WESTERN WISCONSIN...EXTENDING NORTH FROM LOW PRESSURE
IN ALABAMA.
LITTLE CHANGE IS PROGGED TO THE UPPER LEVEL PATTERN ACROSS THE
UPPER MIDWEST INTO THE GREAT LAKES WITH PERHAPS JUST A SLIGHT
BREAKDOWN OF THE UPPER RIDGE OVER THE GREAT LAKES. AS A
RESULT...NOT EXPECTING MUCH CHANGE BETWEEN WHAT HAPPENED TODAY TO
WHAT WILL HAPPEN TOMORROW. IF ANYTHING...WINDS SHOULD BE A BIT
LIGHTER WITH THE HIGH PRESSURE AREA OVER NORTHERN ONTARIO PROGGED
TO DRIFT SOUTH INTO NORTHERN WISCONSIN BY 00Z TUESDAY. PER
200-300MB RH PROGS...LOOKS LIKE THE SCATTERED TO BROKEN HIGH
CLOUDS WILL PERSIST ACROSS THE AREA THROUGH MONDAY. THESE CLOUDS
COMBINED WITH LIGHT NORTHERLY DRY ADVECTION SHOULD PRECLUDE ANY
FOG DEVELOPMENT TONIGHT...DESPITE PERSISTENCE FROM SREF PROGS AND
NMM CORE MODELS WHICH CONTINUE TO SHOW TOO HIGH OF DEWPOINTS. EVEN
WORSE...THE 05.12Z NAM AND NCEP HIRES NMM MODELS BASICALLY HAD FOG
AND TEMPS AROUND 34F AT KRST ALL DAY TODAY. NCEP HIRES ARW
MODELS...WHICH ARE DOING BETTER WITH DEWPOINTS BUT STILL TOO
HIGH...THIS TIME TONIGHT DO NOT SHOW FOG. REGARDING LOW...THE HIGH
CLOUDS TONIGHT WILL KEEP TEMPERATURES UP SOMEWHAT...BUT THE DRY
AIRMASS ALSO SUPPORTS READINGS FALLING...ESPECIALLY IN THE TYPICAL
COLD SPOTS. TRENDED TOWARDS THE COLDER SIDE OF GUIDANCE. ON
MONDAY...850MB TEMPS ARE STILL HOLDING AROUND 8C...SO EXPECTING
HIGHS SIMILAR TO TODAY. ONLY DIFFERENCE WOULD BE OUT WEST WHERE
LESSER SNOW SHOULD ALLOW FOR WARMER TEMPERATURES.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 230 PM CDT SUN MAY 5 2013
MONDAY NIGHT THROUGH WEDNESDAY...ONLY MAIN CONCERN FROM A
PRECIPITATION PERSPECTIVE IS THE UPPER LOW SITUATED OVER CENTRAL
SOUTH DAKOTA. HANDLING OF THIS UPPER LOW HAS BEEN VERY PROBLEMATIC
RUN TO RUN AND BETWEEN MODEL TO MODEL. THERE HAS BEEN A GENERAL SLOW
DOWN IN BRINGING THIS UPPER LOW TOWARDS THE AREA...WHICH MAKES SENSE
AS IT IS CAUGHT IN A LACK OF FLOW BETWEEN THE NORTHERN AND SOUTHERN
STREAMS. THE WAY MODELS EVENTUALLY BRING IT TOWARDS THE AREA IS FROM
A NORTHERN STREAM TROUGH DROPPING INTO SOUTH CENTRAL CANADA...THUS
PICKING UP THE UPPER LOW. THE 05.12Z GFS IS THE FASTEST SOLUTION...
AND QUITE A BIT FASTER COMPARED TO ITS 05.06Z GFS...IMPACTING THE
AREA DURING THE DAY WEDNESDAY. 05.12Z NAM/UKMET/CANADIAN AND
05.00Z/05.12Z ECMWF ARE SLOWER. BELIEVE SLOWER IS THE WAY TO
GO...WHICH WOULD KEEP ANY PRECIPITATION FORCED BY THE UPPER LOW
MOSTLY WEST OF THE AREA. THUS HAVE KEPT ANY PRECIPITATION CHANCES
LOW AND CONFINED TO WESTERN SECTIONS. OTHERWISE...DRY CONDITIONS
WILL PREVAIL UNDER THE INFLUENCE OF HIGH PRESSURE AND LITTLE IN THE
WAY OF FLOW ALOFT. 850MB TEMPS HOLD IN THE 8-10C RANGE FOR BOTH
TUESDAY AND WEDNESDAY...WHICH SHOULD YIELD HIGHS IN THE 70S BOTH
DAYS WITH JUST SOME SCATTERED CLOUDS AROUND. A DRY AIRMASS
ACCOMPANYING THE HIGH...LIGHT WINDS AND THE SCATTERED CLOUDS LIKELY
TO ALLOW FOR DECENT COOLING AT NIGHT. STAYED TOWARDS THE COLD END OF
GUIDANCE...PARTICULARLY FOR THE TYPICAL COLD SPOTS.
WEDNESDAY NIGHT THROUGH SUNDAY...FOCUS AT THE BEGINNING OF THIS
PERIOD REMAINS ON THE UPPER LOW AND A COLD FRONTAL BOUNDARY THAT
LOOKS TO ACCOMPANY THIS UPPER LOW...AS WELL AS THE AFOREMENTIONED
NORTHERN STREAM SHORTWAVE TROUGH. AS MENTIONED THE 05.12Z GFS WAS A
BIT FAST WITH THE UPPER LOW...THUS PREFER THE SLOWER 05.00Z/05.12Z
ECMWF. EITHER SOLUTION REQUIRES AT LEAST SOME CHANCES OF SHOWERS AND
THUNDERSTORMS WITH THE COLD FRONTAL PASSAGE AND EVENTUALLY UPPER
LOW. IT APPEARS THE COLD FRONT WILL SLOWLY DROP SOUTHEAST THROUGH
THE AREA WEDNESDAY NIGHT THROUGH THURSDAY...WITH THE BEST CHANCES OF
PRECIPITATION OVER SOUTHERN PORTIONS OF THE AREA CLOSER TO THE
PROGGED UPPER LOW. CANADIAN HIGH PRESSURE BUILDS IN FOR
FRIDAY...YIELDING DRIER AND SLIGHTLY COOLER CONDITIONS WITH 850MB
TEMPS OF 6-8C.
MODELS CONTINUE TO HINT AT BIG CHANGES FOR THE WEEKEND WITH THE
05.12Z ECMWF/GFS/CANADIAN/GFS ENSEMBLES AND ECMWF ENSEMBLES ALL
SHOWING A POTENT TROUGH DROPPING DOWN INTO THE WESTERN GREAT LAKES
REGION. THIS TROUGH CURRENTLY IS IN THE ARCTIC NORTH OF SIBERIA...
THUS EXPECTING A DECENT COLD SHOT. IN FACT...850MB TEMPS ARE PROGGED
TO PLUMMET TO -4 TO -6C BY 12Z SUNDAY OVER THE FORECAST AREA. A COLD
FRONT LOOKS TO RACE AHEAD OF THIS POTENT TROUGH...WHICH MEANS
BETWEEN THE TWO A LIKELY DEFORMATION BAND OF LIGHT PRECIPITATION.
THUS...CHANCES OF SHOWERS ARE IN THE FORECAST FOR SATURDAY.
TEMPERATURES SATURDAY WILL BE TRICKY...ALL DEPENDING ON WHEN THE
FRONT COMES THROUGH. IF IT IS SLOWER...850MB TEMPS OF 6-8C WOULD
SUPPORT MOST LOCATIONS TOPPING OUT INTO THE 60S AND POSSIBLY EVEN
LOW 70S LIKE THE 05.00Z ECMWF. ON THE OTHER HAND...A FASTER SOLUTION
LIKE THE 05.12Z ECMWF/CANADIAN WOULD BE IN THE 50S...OR COLDER. FOR
NOW WENT WITH THE COMPROMISE AND FOLLOWED A BLEND OF GUIDANCE FOR
TEMPERATURES. DEFINITELY COLDER BUT DRIER FOR SUNDAY AS THE 850MB
THERMAL TROUGH AND CANADIAN AIR MOVE IN. HIGHS LIKELY TO ONLY TOP
OUT IN THE 50S ON SUNDAY...A GOOD 15 DEGREES OR SO BELOW NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1145 PM CDT SUN MAY 5 2013
A BRIEF PERIOD OF MVFR CONDITIONS IN BR IS POSSIBLE AT THE TAF SITES
LATE TONIGHT INTO EARLY MONDAY MORNING. IF THE BR
DEVELOPS...VISIBILITIES WOULD BE REDUCED INTO THE 4-5 SM RANGE.
OTHERWISE...HIGH PRESSURE WILL BRING LIGHT WINDS AND VFR CONDITIONS
TO THE TAF SITES. SCATTERED CIRRUS...WITH CLOUD BASES AT
20KFT...WILL DRIFT FROM SOUTHEAST TO NORTHWEST ACROSS THE TAF SITES
THROUGH THE FORECAST PERIOD STREAMING OFF OF A BROAD CUTOFF LOW
PRESSURE SYSTEM CENTERED OVER NORTHERN ALABAMA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
1035 AM EDT MON MAY 6 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN IN CONTROL OF OUR WEATHER THROUGH
WEDNESDAY MORNING. LOW PRESSURE APPROACHING FROM THE SOUTH WILL
BRING SCATTERED SHOWERS TO THE AREA LATE WEDNESDAY THROUGH FRIDAY.
ANOTHER LOW PRESSURE SYSTEM MOVES IN FROM THE WEST OVER THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
1030 AM UPDATE...MINOR ADJUSTMENTS BASED ON LATEST TRENDS IN
OBSERVATIONAL DATA. FOG/STRATUS HAS BURNED OFF OVER LAND...HOWEVER
IT IS EXPECTED TO COME BACK IN...POSSIBLY AS EARLY AS LATE AFTERNOON
ON THE MID COAST...AND THEN THE REST OF THE COAST THIS EVENING.
TEMPS ON TRACK...LOWERED A BIT ON THE IMMEDIATE COAST.
PREVIOUSLY...
UPDATE...AS EXPECTED STRATUS IS ON THE DOORSTEP OF SRN NH ATTM.
APPEARS AS THOUGH IT WILL NOT MAKE IT MUCH FARTHER N...HOWEVER
VALLEY FOG IS PREVALENT ALONG THE COAST. THIS IS COVERED WELL IN
THE GRIDS...SO HAVE MAINLY USED CURRENT OBS TO ADJUST TEMPS FOR
THE NEXT SEVERAL HRS. HAVE ALSO USED THE LATEST HRRR TO REFINE
WIND FORECAST FOR THE SEA BREEZE.
PREVIOUS DISCUSSION...PERSISTENCE CONTINUES TO RULE THE FORECAST
IN THE NEAR TERM. HIGH PRES CENTERED INVOF NOVA SCOTIA REMAINS IN
CONTROL OF THE REGION. BEING CLOSER TO THE RIDGE AXIS...THE
COASTAL AREAS ARE SEEING SOME OF THE BEST RADIATIONAL COOLING AS A
RESULT. HAVE LEANED ON BIAS CORRECT MOS FOR MIN TEMPS...SEEING AS
THIS STRETCH OF WX HAVE PROVIDED SUFFICIENT DATA AND SIMILAR
CONDS.
KEEPING AN EYE ON COASTAL STRATUS OVER SRN NEW ENGLAND EDGING NWD.
TRACKING ITS CURRENT SPEED...IT WOULD ARRIVE OVER SRN NH AND SWRN
ME NEAR 10 TO 12Z. HAVE SOME HINTS OF IT IN THE GRIDS...BUT NOT
CONFIDENT IT TOTALLY MAKES IT TONIGHT. WILL HAVE TO WATCH MORE FOR
PATCHY FOG IN THE LOW LYING AREAS AS TEMPS BOTTOM OUT.
EXPECTED ANOTHER NICE DAY TODAY...AS TEMPS WARM QUICKLY IN DRY
CONDS. HIGHS WILL CLIMB WELL INTO THE 70S INLAND...WITH SEA
BREEZE/SLY FLOW KEEPING THE COAST CLOSER TO 60.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS RIDGE AXIS CONTINUES TO SLIDE EWD...MORE AND MORE SLY FLOW WILL
HELP TRANSPORT LLVL MOISTURE NWD. NAM IS NOT AS BULLISH AS
ECMWF/GFS/CMC...BUT GIVEN THE GRADUAL NWD DISPLACEMENT EACH NIGHT
EXPECT THAT IT SHOULD REACH THE COAST TONIGHT. INLAND AREAS WILL
REMAIN UNDER CLEAR SKIES.
STRATUS COULD STIFLE EARLY WARMING ALONG THE COAST TUE...BUT
EXPECT ANOTHER PLEASANT DAY WITH HIGHS IN THE 60S ALONG THE COAST
AND 70S TO NEAR 80 INLAND.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
EXTREMELY DRY PATTERN FOR THIS TIME OF THE YEAR WILL GRADUALLY
BECOME MORE SEASONAL AS WE HEAD INTO THE EXTENDED PORTION OF THE
FORECAST. SLOW MOVING...CUTOFF...UPPER LEVEL LOW WILL SLOWLY MOVE
NORTHEAST...WEAKENING AS IT APPROACHES NEW ENGLAND. THIS SYSTEM WILL
ALLOW SCATTERED SHOWERS TO ENTER FAR SOUTHERN AREAS LATE
WEDNESDAY...BEFORE THE LIGHT PCPN SPREADS NORTH.
ALL MODELS ARE RELATIVELY SIMILAR IN THE POSITIONING OF THE SFC
LOW AND MOISTURE COMING IN OFF THE BRINK DURING THE MID TO LATE
PORTION OF THE WORK WEEK. AHEAD OF THIS PCPN...LOW CLOUDS WILL
MOVE IN OFF THE GULF OF MAINE. THIS MOISTURE WILL END OUR PERIOD
OF OUR LARGE DIURNAL RANGES FROM THE DAYTIME MAXES TO THE
OVERNIGHT LOWS.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
SHORT TERM...LOW CHANCE THAT SOME COASTAL STRATUS ARRIVES ACROSS
SRN NH AND SWRN ME NEAR DAYBREAK THIS MORNING. OTHERWISE VFR CONDS
TO PREVAIL UNTIL AFTER 00Z TUE. IFR CONDS ARE EXPECTED FOR COASTAL
TERMINALS AS CIGS AND POSSIBLY VSBYS DECREASE IN STRATUS.
LONG TERM...
MARINE FOG LOOKS LIKELY TUESDAY AND WEDNESDAY MORNINGS RESULTING
IN SOME AREAS OF MVFR OR LOWER. SCATTERED SHOWERS ENTER THE REGION
FROM SOUTH TO NORTH WEDNESDAY NIGHT THROUGH THE END OF THE WORK
WEEK.
&&
.MARINE...
SHORT TERM...LONG PERIOD SWELL AROUND 5 FT WILL CONTINUE EARLY
THIS MORNING. GIVEN LACK OF STEEPNESS TO THE SEAS...NO SCA IS
EXPECTED. WINDS WILL REMAIN BLO 25 KT.
LONG TERM...
MARINE FOG IS LIKELY TUESDAY AND WEDNESDAY MORNINGS
WITH POOR VISIBILITY. WINDS WILL REMAIN BELOW SMALL CRAFT CRITERIA.
SEAS MAY BRIEFLY REACH 5 FT THURSDAY.
&&
.FIRE WEATHER...
HIGH PRESSURE WILL REMAIN IN CONTROL OF THE WEATHER WITH NO RAIN
EXPECTED THROUGH TUESDAY. DAYTIME RELATIVE HUMIDITY WILL APPROACH
25% AWAY FROM THE COAST BUT WINDS ARE EXPECTED TO REMAIN
RELATIVELY LIGHT THROUGH THE PERIOD. A CHANCE FOR WETTING RAINS
WILL ARRIVE LATER WEDNESDAY ACROSS THE SOUTH...AND BY THURSDAY
FOR NORTHERN ZONES.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
LEGRO/JC/MLE
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
634 AM EDT MON MAY 6 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN IN CONTROL OF OUR WEATHER THROUGH
WEDNESDAY MORNING. LOW PRESSURE APPROACHING FROM THE SOUTH WILL
BRING SCATTERED SHOWERS TO THE AREA LATE WEDNESDAY THROUGH FRIDAY.
ANOTHER LOW PRESSURE SYSTEM MOVES IN FROM THE WEST OVER THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...AS EXPECTED STRATUS IS ON THE DOORSTEP OF SRN NH ATTM.
APPEARS AS THOUGH IT WILL NOT MAKE IT MUCH FARTHER N...HOWEVER
VALLEY FOG IS PREVALENT ALONG THE COAST. THIS IS COVERED WELL IN
THE GRIDS...SO HAVE MAINLY USED CURRENT OBS TO ADJUST TEMPS FOR
THE NEXT SEVERAL HRS. HAVE ALSO USED THE LATEST HRRR TO REFINE
WIND FORECAST FOR THE SEA BREEZE.
PREVIOUS DISCUSSION...PERSISTENCE CONTINUES TO RULE THE FORECAST
IN THE NEAR TERM. HIGH PRES CENTERED INVOF NOVA SCOTIA REMAINS IN
CONTROL OF THE REGION. BEING CLOSER TO THE RIDGE AXIS...THE
COASTAL AREAS ARE SEEING SOME OF THE BEST RADIATIONAL COOLING AS A
RESULT. HAVE LEANED ON BIAS CORRECT MOS FOR MIN TEMPS...SEEING AS
THIS STRETCH OF WX HAVE PROVIDED SUFFICIENT DATA AND SIMILAR
CONDS.
KEEPING AN EYE ON COASTAL STRATUS OVER SRN NEW ENGLAND EDGING NWD.
TRACKING ITS CURRENT SPEED...IT WOULD ARRIVE OVER SRN NH AND SWRN
ME NEAR 10 TO 12Z. HAVE SOME HINTS OF IT IN THE GRIDS...BUT NOT
CONFIDENT IT TOTALLY MAKES IT TONIGHT. WILL HAVE TO WATCH MORE FOR
PATCHY FOG IN THE LOW LYING AREAS AS TEMPS BOTTOM OUT.
EXPECTED ANOTHER NICE DAY TODAY...AS TEMPS WARM QUICKLY IN DRY
CONDS. HIGHS WILL CLIMB WELL INTO THE 70S INLAND...WITH SEA
BREEZE/SLY FLOW KEEPING THE COAST CLOSER TO 60.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS RIDGE AXIS CONTINUES TO SLIDE EWD...MORE AND MORE SLY FLOW WILL
HELP TRANSPORT LLVL MOISTURE NWD. NAM IS NOT AS BULLISH AS
ECMWF/GFS/CMC...BUT GIVEN THE GRADUAL NWD DISPLACEMENT EACH NIGHT
EXPECT THAT IT SHOULD REACH THE COAST TONIGHT. INLAND AREAS WILL
REMAIN UNDER CLEAR SKIES.
STRATUS COULD STIFLE EARLY WARMING ALONG THE COAST TUE...BUT
EXPECT ANOTHER PLEASANT DAY WITH HIGHS IN THE 60S ALONG THE COAST
AND 70S TO NEAR 80 INLAND.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
EXTREMELY DRY PATTERN FOR THIS TIME OF THE YEAR WILL GRADUALLY
BECOME MORE SEASONAL AS WE HEAD INTO THE EXTENDED PORTION OF THE
FORECAST. SLOW MOVING...CUTOFF...UPPER LEVEL LOW WILL SLOWLY MOVE
NORTHEAST...WEAKENING AS IT APPROACHES NEW ENGLAND. THIS SYSTEM WILL
ALLOW SCATTERED SHOWERS TO ENTER FAR SOUTHERN AREAS LATE
WEDNESDAY...BEFORE THE LIGHT PCPN SPREADS NORTH.
ALL MODELS ARE RELATIVELY SIMILAR IN THE POSITIONING OF THE SFC
LOW AND MOISTURE COMING IN OFF THE BRINK DURING THE MID TO LATE
PORTION OF THE WORK WEEK. AHEAD OF THIS PCPN...LOW CLOUDS WILL
MOVE IN OFF THE GULF OF MAINE. THIS MOISTURE WILL END OUR PERIOD
OF OUR LARGE DIURNAL RANGES FROM THE DAYTIME MAXES TO THE
OVERNIGHT LOWS.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
SHORT TERM...LOW CHANCE THAT SOME COASTAL STRATUS ARRIVES ACROSS
SRN NH AND SWRN ME NEAR DAYBREAK THIS MORNING. OTHERWISE VFR CONDS
TO PREVAIL UNTIL AFTER 00Z TUE. IFR CONDS ARE EXPECTED FOR COASTAL
TERMINALS AS CIGS AND POSSIBLY VSBYS DECREASE IN STRATUS.
LONG TERM...
MARINE FOG LOOKS LIKELY TUESDAY AND WEDNESDAY MORNINGS RESULTING
IN SOME AREAS OF MVFR OR LOWER. SCATTERED SHOWERS ENTER THE REGION
FROM SOUTH TO NORTH WEDNESDAY NIGHT THROUGH THE END OF THE WORK
WEEK.
&&
.MARINE...
SHORT TERM...LONG PERIOD SWELL AROUND 5 FT WILL CONTINUE EARLY
THIS MORNING. GIVEN LACK OF STEEPNESS TO THE SEAS...NO SCA IS
EXPECTED. WINDS WILL REMAIN BLO 25 KT.
LONG TERM...
MARINE FOG IS LIKELY TUESDAY AND WEDNESDAY MORNINGS
WITH POOR VISIBILITY. WINDS WILL REMAIN BELOW SMALL CRAFT CRITERIA.
SEAS MAY BRIEFLY REACH 5 FT THURSDAY.
&&
.FIRE WEATHER...
HIGH PRESSURE WILL REMAIN IN CONTROL OF THE WEATHER WITH NO RAIN
EXPECTED THROUGH TUESDAY. DAYTIME RELATIVE HUMIDITY WILL APPROACH
25% AWAY FROM THE COAST BUT WINDS ARE EXPECTED TO REMAIN
RELATIVELY LIGHT THROUGH THE PERIOD. A CHANCE FOR WETTING RAINS
WILL ARRIVE LATER WEDNESDAY ACROSS THE SOUTH...AND BY THURSDAY
FOR NORTHERN ZONES.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
LEGRO/JC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
730 AM EDT MON MAY 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM EDT MON MAY 6 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG STRETCHING
FM THE NE CONUS W INTO THE UPR GRT LKS TO THE N OF CUTOFF LO OVER
THE SE CONUS. VERY DRY AIRMASS SHOWN ON THE 00Z GRB/APX RAOBS...
WHICH SHOW A PWAT ARND 0.25 INCH OR 50 PCT OF NORMAL...DOMINATES THE
CWA. SO SKIES ARE MOCLR EXCEPT FOR SOME HI CLDS. SFC HI PRES IS
CENTERED NEAR WRN LK SUP...AND SOME LO CLDS/FOG ARE APRNT OVER WRN
LK SUP NEAR THE W COAST OF UPR MI CLOSER TO MOISTER AIRMASS SHOWN ON
THE 00Z INL RAOB. DESPITE THE LGT WINDS AND TEMPS FALLING TOWARD 30
CLOSER TO THIS MSTR...NO FOG HAS YET FORMED OVER WRN UPR MI AS OF
FCST ISSUANCE.
TODAY/TNGT...UPR RDG IS FCST TO REMAIN DOMINANT THRU THIS TIME WITH
SFC HI PRES REMAINING NEARLY STNRY OVER LK SUP. WITH DRY AIRMASS
ALSO LINGERING...THE ONLY MAJOR CONCERNS ARE TEMPS...THE POTENTIAL
FOR FOG THIS MRNG/TNGT...AND POTENTIAL LOW RH THIS AFTN...ESPECIALLY
OVER THE E HALF CLOSER TO CORE OF DRY AIRMASS. BEST CHC FOR FOG
EARLY THIS MRNG WL BE OVER THE INTERIOR W...CLOSER TO AREA OF FOG/
LO CLD STRETCHING FM THE W SHORE OF THE KEWEENAW DOWN TOWARD
IWD/ASX. ANY FOG THAT DOES DVLP SHOULD BURN OFF FAIRLY QUICKLY WITH
THE ONSET OF DAYTIME HEATING.
WITH H85 TEMPS TOPPING OUT AT 9-10C AGAIN TODAY...EXPECT MAX TEMPS
TO BE SIMILAR TO WHAT OCCURRED YDAY AT MOST LOCATIONS. THE ONLY
EXCEPTION WL BE OVER THE NCENTRAL AND W NEAR LK SUP...WHERE A WEAKER
SYNOPTIC FLOW THAN YDAY WL LIMIT THE INLAND EXTENT OF LK MODERATION.
SO ALTHOUGH TEMPS NEAR THE SHORE IN THIS AREA MIGHT HAVE A HARD TIME
TOPPING 50...MUCH OF THE NCENTRAL AND W WL BE WARMER THAN YDAY.
MIXING TO H8-85 ON NAM/GFS FCST SDNGS YIELDS HI TEMPS UP TO 70-75
OVER THE INTERIOR AWAY FM LOCAL LK BREEZE MODERATION. PREFER THE
DRIER LOOK TO THE NAM FCST SDNGS GIVEN BONE DRY GRB/APX RAOBS. DEEP
MIXING ON THESE FCST SDNGS SUG DEWPTS WL MIX OUT AS LO AS 30 TO 35
OVER THE INTERIOR DURING PEAK HEATING...LOWERING MIN RH AS LO AS
20-25 PCT. THE BEST CHC FOR THE LOWER DEWPTS WL BE OVER THE E WHERE
THE GROUND IS QUITE A BIT DRIER THAN OVER THE W/CENTRAL. FORTUNATELY
WINDS WL BE LGT...SO NO FIRE WX HEADLINES ARE NECESSARY.
FOR TNGT...WITH LGT WINDS AND DRY AIRMASS LINGERING...EXPECT A
HEALTHY DROP OF TEMP. PREFER TO TEND TOWARD THE LOWER END OF
GUIDANCE FOR MIN TEMPS...BUT MODERATING AIRMASS SUGGESTS TEMPS TNGT
WL NOT BE AS CHILLY AS EARLY THIS MRNG. SINCE FOG HAS BEEN SLOW TO
FORM THIS MRNG AND THE LLVLS TNGT WL LIKELY TO BE AS DRY...OPTED TO
MAINTAIN FCST FOR PATCHY FOG ONLY OVER THE INTERIOR W WHERE TEMPS AT
SOME OF THE FAVORED COOL SPOTS SEE MIN TEMPS FALLING TOWARD 33.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 355 AM EDT MON MAY 6 2013
THE QUIET WEATHER WILL CONTINUE FOR THE START OF THE LONG TERM
PERIOD...AS DUAL CUTOFF LOWS /ONE OVER THE SE CONUS AND THE OTHER
NEAR CALIFORNIA/ KEEP THE UNSETTLED WEATHER OVER THE SOUTHERN HALF
OF THE CONUS. MEANWHILE...THE NORTHERN STREAM JET RUNNING WEST-EAST
ACROSS CENTRAL CANADA WILL KEEP THE COLDER AIR LOCKED UP TO THE
NORTH FOR THE TIME BEING.
AT THE SURFACE...HIGH PRESSURE WILL STILL BE OVER THE UPPER GREAT
LAKES FOR TUESDAY INTO WEDNESDAY MORNING AND PRODUCE MOSTLY CLEAR
SKIES ACROSS THE AREA. THERE ARE STILL HINTS OF SOME HIGH-BASED
DIURNAL CU OVER THE WESTERN CWA ON TUESDAY AFTERNOON...BUT NOT
EXPECTING MUCH MORE THAN THAT. WITH THE DEEP MIXING...EXPECT
ANOTHER ABOVE NORMAL DAY OVER THE CWA...WITH HIGHS IN THE 70S
EXCEPT WHERE LAKE BREEZES KEEP TEMPERATURES COOLER NEAR THE GREAT
LAKES. TEMPERATURES SHOULD BE SIMILAR ON WEDNESDAY...ALTHOUGH THE
INCREASING CLOUDS AND POTENTIAL PRECIPITATION MAY KEEP THE WEST
HALF A LITTLE COOLER. DID TREND DEWPOINTS DOWN FOR TUESDAY AFTERNOON
OVER THE CENTRAL AND EAST BASED OFF THE LAST COUPLE OF DAYS. WITH
THE GOOD MIXING THOSE DAYS...RH VALUES FELL INTO THE UPPER TEENS AND
20S AWAY FROM THE LAKE INFLUENCES AND WOULD EXPECT THE SAME FOR
TUESDAY. THAT IDEA MATCHES MIXED LAYER DEWPOINTS FROM THE MODELS AND
TRENDED THAT DIRECTION.
THE FIRST CHANCE OF PRECIPITATION FOR THE LONG TERM PERIOD WILL
COME LATE WEDNESDAY AFTERNOON AND INTO WEDNESDAY NIGHT. THIS IS DUE
TO A SHORTWAVE IN THE NORTHERN STREAM WAVE PRODUCING A LOW THAT
SHIFTS EAST INTO QUEBEC ON WEDNESDAY. A TRAILING COLD FRONT WILL
THEN TRY TO DIVE SOUTHEAST ACROSS THE UPPER GREAT LAKES ON
WEDNESDAY NIGHT INTO THURSDAY MORNING. THE MAIN FORECAST IMPACT IS
WHAT WILL HAPPEN WITH THE MOISTURE AND SMALL CLOSED PIECE OF ENERGY
THAT TRIES TO DRIFT NORTHEAST AND INTERACT WITH THE NORTHERN
STREAM. THE MODELS CONTINUE TO DIFFER WITH THIS INTERACTION AND
PROVIDES UNCERTAINTY IN THE QPF AMOUNTS. WILL CONTINUE TO GO WITH A
GENERAL CONSENSUS POP/QPF DURING THIS PERIOD AND HAVE SLIGHTS
OR LOW CHANCE POPS FOR LATE WEDNESDAY AFTERNOON INTO THURSDAY
MORNING.
WITH THE COLD FRONT MOVING SOUTHEAST OF THE AREA...EXPECT DRIER AIR
TO DIMINISHING PRECIPITATION CHANCES BY THURSDAY AFTERNOON AS A
CANADIAN HIGH PRESSURE RIDGE DROPS OVER THE AREA. THIS RIDGE WILL
REMAIN OVER THE AREA FOR FRIDAY AND LEAD TO DRY BUT COOLER WEATHER
WITH HIGHS IN THE 50S.
A MUCH STRONGER NORTHERN STREAM WAVE WILL BE DIVING SOUTHEAST
TOWARDS THE UPPER GREAT LAKES ON SATURDAY AND BRING MUCH COOLER
WEATHER FOR THE WEEKEND. WILL CONTINUE THE CHANCE POPS WITH THIS
SYSTEM...BUT WITH LITTLE MOISTURE RETURN AHEAD OF THE WAVE...QPF
AMOUNTS WILL BE ON THE LIGHT SIDE. PRECIPITATION SHOULD FALL AS
RAIN...AS THE COLDEST AIR DOESN/T ARRIVE UNTIL AFTER MOST OF THE
DEEP MOISTURE EXITS. WITH THE BETTER CONSISTENCY IN THE MODELS FOR
THIS WAVE...HAVE TRENDED HIGHS DOWN INTO THE UPPER 40S OR LOWER 50S
FOR SATURDAY ALTHOUGH THERE IS SOME CONCERNS THE EAST COULD SEE
WARMER HIGHS AROUND DAYBREAK AND THEN FALLING THROUGH THE DAY. THE
TROUGH WILL QUICKLY SHIFT EAST TO THE NEW ENGLAND STATES ON SUNDAY
AND ALLOW RETURN FLOW TO DEVELOP. SUNDAY SHOULD BE DRY BUT COOL BUT
THEN WARMING IS EXPECTED FOR THE FIRST PART OF NEXT WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 728 AM EDT MON MAY 6 2013
EXPECT VFR CONDITIONS/LIGHT WINDS THIS TAF PERIOD WITH DRY HI PRES
DOMINATING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 355 AM EDT MON MAY 6 2013
A QUIET PERIOD OF WEATHER IS EXPECTED THROUGH THE PERIOD...WITH THE
WINDS LIKELY STAYING BELOW 25KTS. HIGH PRESSURE THAT HAS SETUP OVER
THE AREA WILL REMAIN THROUGH WEDNESDAY MORNING AND LEAD TO LIGHT
WINDS. THEN...A COLD FRONT DROPPING SOUTHEAST ACROSS THE UPPER GREAT
LAKES ON WEDNESDAY NIGHT WILL BRING A WIND SHIFT BUT ONLY 10-20KT
WINDS. WEAK HIGH PRESSURE WILL MOVE OVER NORTHERN LAKE SUPERIOR FOR
THURSDAY AFTERNOON INTO FRIDAY AND DIMINISH THE WINDS.
&&
.HYDROLOGY...
ISSUED AT 355 AM EDT MON MAY 6 2013
HYDROLOGY CONCERNS WILL REMAIN OVER THE COMING DAYS...UNTIL THE
REMAINING SNOW PACK MELTS OVER THE NORTHWESTERN THIRD OF UPPER
MICHIGAN. VISIBLE SATELLITE AND MODIS IMAGERY YESTERDAY STILL SHOWS
SNOW REMAINING IN THE HIGHER TERRAIN LOCATIONS OF THE HURON
MOUNTAINS AND THE KEWEENAW PENINSULA. DID SEE RISES AT SOME OF THE
SITES OVER THE WEST /ESPECIALLY TRRM4/ WITH THE WARMER TEMPERATURES
YESTERDAY AND WOULD EXPECT THAT TO CONTINUE UNTIL THE REMAINING
SNOW IS GONE. AT THIS TIME...WOULD THINK TRRM4 WILL BE THE MAIN
THREAT FOR REACHING ADVISORY OR FLOOD STAGE FROM THIS ADDITIONAL
MELT.
OTHERWISE...THE ONGOING FLOODING ON THE STURGEON RIVER AT ALSTON AND
CHASSELL...THE MICHIGAMME RIVER AROUND WITCH LAKE...AND THE PAINT
RIVER NEAR CRYSTAL FALLS WILL REMAIN A CONCERN FOR THE NEXT COUPLE
OF DAYS. THE REST RIVER LEVELS ARE ON THE DOWNWARD TREND AND
WILL LIKELY CONTINUE THIS WEEK.
FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD WARNINGS AND
ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...SRF
AVIATION...KC
MARINE...SRF
HYDROLOGY...SRF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
717 AM CDT MON MAY 6 2013
.UPDATE...
ISSUED AT 717 AM CDT MON MAY 6 2013
SENT A QUICK ENHANCED SHORT-TERM FCST /ESTF/ UPDATE AS HOURLY
TEMPS/DWPTS WERE RUNNING WAY ABOVE REALITY 12-13Z.
STILL SEEING SHALLOW 1/4SM VSBY OR LESS WITHIN THE ADVY. SO NO
CHANGES TO THE HEADLINE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 403 AM CDT MON MAY 6 2013
OVERNIGHT UPPER AIR ANALYSIS INDICATES A MID TO UPPER LEVEL OMEGA
PATTERN WITH MID TO UPPER LEVEL LOWS OVER THE WESTERN AND
SOUTHEASTERN CONUS...AND RIDGING OVER THE CENTRAL CONUS. MID AND
UPPER LEVEL JET ENERGY REMAINS RELEGATED WELL TO OUR SOUTH AND AS
A RESULT...MID AND UPPER LEVEL FLOW OVER THE CENTRAL PLAINS
REMAINS VERY WEAK. WATER VAPOR IMAGERY SHOWS THE TWO
AFOREMENTIONED MID LEVEL LOWS...WITH INCREASED VALUES OF MID LEVEL
MOISTURE WRAPPING AROUND THE SOUTHEASTERN CONUS LOW INTO PORTIONS
OF THE OHIO RIVER VALLEY AND THE MID MISSISSIPPI VALLEY...AND
INCREASED VALUES OF MID LEVEL MOISTURE ALSO NOTED OVER THE WESTERN
CONUS AHEAD OF THE WESTERN CONUS LOW. WATER VAPOR IMAGERY ALSO
INDICATES A SUBTLE MID LEVEL SHORT WAVE OVER THE SOUTHWESTERN
CONUS...PIVOTING TO THE SOUTHEAST OF THE WESTERN CONUS MID LEVEL
LOW. AT THE SURFACE A RIDGE OF HIGH BAROMETRIC PRESSURE EXISTS
FROM NORTH TO SOUTH ACROSS OUR CWA AND AS A RESULT...THE LOW LEVEL
WIND FIELD ACROSS OUR AREA REMAINS LIGHT. THE LIGHT LOW LEVEL WIND
FIELD...WORKING IN CONCERT WITH DECREASING LOW LEVEL DEWPOINT
DEPRESSIONS...HAS PROMOTED THE DEVELOPMENT OF FOG ACROSS MUCH OF
OUR AREA THIS MORNING.
GIVEN THE CURRENT FOG BEING OBSERVED ACROSS THE AREA...WILL
CONTINUE FOG MENTION IN THE FORECAST THROUGH 14Z THIS MORNING. AS
OF 09Z KODX...KHSI AND KAUH HAVE DROPPED TO 1/4SM WITH SEVERAL
OTHER SITE IN THE AREA ALSO DROPPING NEAR 1/4SM. GIVEN ALL
THIS...WENT AHEAD WITH A DENSE FOG ADVISORY...FOR LOCATIONS
GENERALLY EAST OF A KODX TO KEAR LINE AND NORTH OF HIGHWAY 6. THIS
FOG APPEARS TO BE VERY SHALLOW...BASED ON LAPS AND RAP ANALYSIS
POINT SOUNDINGS AS WELL AS OBSERVATION HERE AT THE OFFICE. AS A
RESULT...INCREASED DIABATIC HEATING AND RESULTANT INCREASING
BOUNDARY LAYER DEPTH AND MIXING SHOULD ALLOW THE FOG TO QUICKLY
DISSIPATE POST-SUNRISE...WITH FULL VISIBILITY EXPECTED AT MOST
SITES BY 14Z.
AN OVERALL LACK IN KINEMATIC FORCING IS EXPECTED TO KEEP OUR AREA
DRY TODAY. THE SUBTLE MID LEVEL SHORT WAVE...CURRENTLY OVER THE
SOUTHWESTERN CONUS...IS EXPECTED TO CONTINUE MOVING EAST/NORTHEAST
TODAY AND BY THIS EVENING...SHOULD BE MOVING ACROSS THE SOUTHERN
TO CENTRAL ROCKY MOUNTAIN RANGE. MID LEVEL THERMAL ADVECTION AND
RESULTANT OMEGA AHEAD OF THE SHORT WAVE TROUGH AXIS APPEARS AS
THOUGH IT WILL BE STRONG ENOUGH FOR PRECIPITATION PRODUCTION
ACROSS THE SOUTHERN TO CENTRAL HIGH PLAINS LATE THIS AFTERNOON
INTO THIS EVENING. SHORTLY AFTER SUNSET TONIGHT...A ~30KT 850MB
JET STREAK IS EXPECTED TO DEVELOP FROM SOUTH TO NORTH ACROSS THE
SOUTHERN AND CENTRAL HIGH PLAINS. THIS 850MB JET STREAK IS THEN
EXPECTED TO PROPAGATE EAST SOMEWHAT DURING THE OVERNIGHT HOURS AND
BY 12Z TUESDAY...THE EASTERN PERIPHERY OF THIS 850MB JET AXIS WILL
BRUSH UP AGAINST WEST/SOUTHWESTERN PORTIONS OF OUR CWA. LOW LEVEL
THERMAL ADVECTION ALONG THE 850MB JET STREAK AXIS APPEARS AS
THOUGH IT WILL ALLOW LATE AFTERNOON/EVENING PRECIPITATION ACROSS
THE HIGH PLAINS TO HOLD TOGETHER POST-SUNSET...AND MOVE INTO
WESTERN/SOUTHWESTERN PORTIONS OF OUR CWA 06-12Z TUESDAY. THIS IS A
SOLUTION SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL
GFS...EC AND SREF-MEAN. GIVEN THE MODEL AGREEMENT AND THE APPARENT
LIKELIHOOD THAT SOME LOCATIONS ACROSS OUR WEST/SOUTHWEST COULD
PICKUP UPWARDS OF A TENTH OF AN INCH OF PRECIPITATION...OPTED TO
INCREASE POPS INTO THE 40-50% RANGE ACROSS OUR FAR WEST/SOUTHWEST
06-12Z TUESDAY. LOCATIONS FATHER EAST/NORTHEAST ALSO HAVE POPS IN
PLACE FOR TONIGHT...ALBEIT SUBSTANTIALLY LOWER IN THE 20-30% RANGE
AS CONFIDENCE IS NOT NEARLY AS HIGH THAT FAR EAST WITH THE 850MB
JET STREAK AXIS EXPECTED TO REMAIN FARTHER WEST.
MOISTURE FLUX ALONG THE 850MB JET STREAK AXIS...AS WELL AS THE
700MB JET STREAK AXIS...WORKING IN CONCERT WITH INCREASING MID
LEVEL LAPSE RATES WITH THE APPROACH OF THE SUBTLE MID LEVEL SHORT
WAVE...IS EXPECTED TO PROVIDE INCREASING POTENTIAL INSTABILITY
ACROSS OUR AREA TONIGHT. THE NAM IN PARTICULAR SUGGESTS PARCELS
ROOTED TO BETWEEN 850MB AND 750MB WILL HAVE 50-100J/KG OF CAPE TO
WORK WITH AND CIN RANGING BETWEEN NEAR-ZERO AND AROUND -20J/KG.
GIVEN ALL THIS...ISOLATED CONVECTION CERTAINLY SEEMS POSSIBLE
EMBEDDED WITHIN THE STRATIFORM RAIN EVENT OCCURRING ALONG THE LOW
LEVEL JET AXIS. GIVEN ALL THIS WENT AHEAD AND ADDED ISOLATED
THUNDER MENTION TO THE FORECAST FOR OUR CWA FOR TONIGHT.
THE SURFACE RIDGE CURRENTLY OVER THE AREA IS EXPECTED TO PUSH EAST
LATER TODAY...ALLOWING FOR WEAK LOW LEVEL RETURN FLOW ACROSS MUCH
OF OUR AREA BY THIS AFTERNOON. SUBTLE LOW LEVEL WARM AIR
ADVECTION...AS WELL AS INCREASED DIABATIC HEATING...WHEN COMPARED
TO SUNDAY SHOULD ALLOW FOR A WARMER DAY ACROSS OUR CWA TODAY. AN
AFTERNOON HIGH TEMPERATURE IN THE UPPER 60S TO LOWER 70S IS
FORECAST FOR MOST LOCATIONS FOR TODAY AS A RESULT. INCREASING
CLOUD COVER...POSSIBLE PRECIPITATION...AND CONTINUED SOUTHEASTERLY
LOW LEVEL FLOW SHOULD PRESENT A WARMER OVERNIGHT LOW TEMPERATURE
TONIGHT WHEN COMPARED TO EARLY THIS MORNING. A TUESDAY MORNING LOW
TEMPERATURE IN THE MID TO UPPER 40S IS FORECAST FOR MOST LOCATIONS
ACROSS OUR CWA AS A RESULT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 403 AM CDT MON MAY 6 2013
TUESDAY THROUGH SUNDAY. MAIN FORECAST CONCERNS WILL BE CHANCES FOR
SHOWERS AND THUNDERSTORMS TUESDAY THROUGH SATURDAY AND
TEMPERATURES.
AN UNSETTLED PATTERN WILL BE FOUND ACROSS THE CENTRAL PLAINS FOR
TUESDAY THROUGH SATURDAY. A WEAK RIDGE SETS UP BETWEEN A STRONG
UPPER LEVEL LOW TO THE WEST AND ANOTHER TO THE EAST. DESPITE THE
RIDGE...THERE WILL BE SEVERAL RELATIVELY WEAK UPPER LEVEL LOW
PRESSURE SYSTEMS THAT WILL AFFECT THE AREA FOR THE TUESDAY THROUGH
SATURDAY PERIOD. DO NOT EXPECT THAT IT WILL BE RAINING ALL OF THE
TIME FOR EACH OF THESE PERIODS...BUT THERE IS A CHANCE FOR SHOWERS
AND THUNDERSTORMS ON AND OFF THROUGH THE PERIOD. THE STRONGEST
UPPER LEVEL LOWS THAT MOVE THROUGH THE AREA WILL BE FOR TUESDAY
AND TUESDAY NIGHT AND AGAIN WEDNESDAY NIGHT. THESE WILL BRING THE
BEST CHANCES FOR PRECIPITATION. THE MUCAPE FOR TUESDAY AFTERNOON
AND EVENING WILL REACH AROUND 750 J/KG WHICH SHOULD BE ENOUGH FOR
SOME ISOLATED SEVERE WEATHER...BUT WEDNESDAY AFTERNOON AND EVENING
MUCAPE VALUES APPROACH 2500 J/KG WHICH WOULD INDICATE A BETTER
CHANCE FOR SOME SEVERE STORMS. THERE ARE STILL SOME DIFFERENCES IN
THE MODELS AND WILL HAVE TO WATCH TO SEE HOW MUCH CHANGE THERE IS
OVER THE NEXT COUPLE DAYS.
FOR THURSDAY THROUGH SATURDAY THE UPPER LEVEL LOW IN THE WESTERN
CONUS WILL DRIFT TO THE EAST AND INTO THE PLAINS. THIS WILL
CONTINUE TO BRING CHANCES FOR SHOWERS WITH SOME ISOLATED
THUNDERSTORMS. MU CAPE VALUES DECREASE TO LESS THAN 200 J/KG.
TEMPERATURES SHOULD REMAIN AROUND NORMAL FOR THIS TIME OF YEAR
THROUGH FRIDAY...BUT AS A COLD FRONT MOVES SOUTH INTO THE AREA ON
SATURDAY EXPECT SOME SHOWERS AND THUNDERSTORMS BEHIND THE FRONT
AND TEMPERATURES WILL COOL OFF A FEW DEGREES. A COOL SURFACE HIGH
PRESSURE SYSTEM SETTLES INTO THE REGION FOR SATURDAY NIGHT INTO
SUNDAY AND TEMPERATURES WILL REMAIN A BIT COOLER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 515 AM CDT MON MAY 6 2013
LIFR TO VLIFR CONDITIONS EXPECTED UNTIL 14Z...WITH VFR CONDITIONS
EXPECTED BY 14 AND BEYOND.
DENSE FOG HAS INFILTRATED MUCH OF SOUTH CENTRAL NEBRASKA THIS
MORNING WITH SEVERAL SITES NEAR KGRI AT OR BELOW 1/4SM. GIVEN THE
VISIBILITY TRENDS AT KGRI THROUGH THE PAST COUPLE HOURS...OPTED TO
GO WITH PREVAILING LIFR VISIBILITY THROUGH 14Z...WITH TEMPO VLIFR
VISIBILITY ALSO THROUGH 14Z. THIS FOG APPEARS TO BE VERY
SHALLOW...BASED ON LAPS AND RAP ANALYSIS POINT SOUNDINGS AS WELL
AS OBSERVATION HERE AT THE OFFICE. AS A RESULT...INCREASED
DIABATIC HEATING AND RESULTANT INCREASING BOUNDARY LAYER DEPTH AND
MIXING SHOULD ALLOW THE FOG TO QUICKLY DISSIPATE POST-
SUNRISE...WITH FULL VISIBILITY EXPECTED BY 14Z. SCATTERED MID TO
HIGH LEVEL CLOUDS WILL CONTINUE AT KGRI THROUGH THE NEXT 24
HOURS...ALTHOUGH A BROKEN DECK NEAR 5000FT AGL IS POSSIBLE TOWARDS
THE END OF THE TAF PERIOD. THE PRESENCE OF A SURFACE RIDGE WILL
KEEP THE SURFACE WIND LIGHT AND VARIABLE THIS MORNING...BEFORE
BECOMING MORE ESTABLISHED FROM THE SOUTHEAST THIS AFTERNOON. THERE
IS A CHANCE OF MEASURABLE PRECIPITATION AND CONVECTIVE ACTIVITY
06Z-12Z TUESDAY...HOWEVER THE PROBABILITY OF SUCH ACTIVITY BEING
REALIZED AT KGRI IS TOO LOW FOR INSERTION INTO THE TAF AT THIS
TIME.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR NEZ039>041-
046>049-060>064-072>077.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...BRYANT
LONG TERM...JCB
AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
637 AM CDT MON MAY 6 2013
.SYNOPSIS...
ISSUED AT 407 AM CDT MON MAY 6 2013
H5 ANALYSIS TONIGHT HAS THREE AREAS OF CLOSED LOW
PRESSURE OVER THE CONUS. THE FIRST WAS OVER NRN ALABAMA...THE SECOND
OFF THE NRN CA COAST AND A THIRD WEAKER SYSTEM WAS NOTED OVER
CENTRAL SOUTH DAKOTA. AT THE SURFACE...WEAK HIGH PRESSURE WAS
ANCHORED ACROSS NORTHERN NEBRASKA AND SOUTHERN SOUTH DAKOTA ATTM.
RADIATIONAL COOLING UNDERNEATH THE HIGH...HAS LED TO SOME PATCHY FOG
ACROSS NORTHEASTERN PORTIONS OF THE FORECAST AREA OVER THE PAST
HOUR...WITH VISBYS DOWN TO QUARTER MILE AT ONEILL. COMPARED TO 24
HOURS AGO...TEMPERATURES ARE MUCH WARMER ATTM WITH 3 AM CDT TEMPS
RANGING FROM THE LOWER 30S IN THE NORTHEAST...TO THE LOWER 40S IN
THE EASTERN PANHANDLE AND FAR SOUTHWESTERN NEBRASKA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 407 AM CDT MON MAY 6 2013
THE MAIN FORECAST CHALLENGES OVER THE NEXT 24 HOURS ARE
TEMPERATURES TODAY...AND THE THREAT FOR THUNDERSTORMS LATER
TONIGHT. FOR THIS MORNING...OBSERVATIONS...SATELLITE IMAGERY AND
HIGHWAY CAMS...CONTINUE TO INDICATE FOG ACROSS THE NORTHEASTERN
CWA ATTM. THE LATEST VISIBILITY FOR ONEILL IS AROUND A QUARTER
MILE. DECIDED TO HOIST A DENSE FOG ADVISORY TO COVER THIS THREAT
THROUGH MID MORNING. ATTM...THE DENSE FOG THREAT APPEARS LOCALIZED
WITH THE LOWEST VISBYS IN LOW LYING AREAS AND RIVER VALLEYS. BASED
ON THE HRRR AND NAM12 BL RH FIELD...FOG SHOULD QUICKLY BURN OFF BY
MID MORNING...WITH VISBYS IMPROVING QUICKLY AFTER 14Z. BASED ON
THE HRRR...THE GREATEST THREAT FOR FOG SHOULD REMAIN ALONG AND
EAST OF HIGHWAY 183. FOR THE REMAINDER OF TODAY...SRLY WINDS WILL
INCREASE THIS AFTERNOON AS HIGH PRESSURE MOVES EAST OF THE
AREA...AND LEE TROUGHING DEEPENS ACROSS EASTERN WYOMING AND
EASTERN COLORADO. THE SRLY WINDS...WILL PUSH WARMER AIR AND
INCREASED LOW LEVEL MOISTURE FROM THE SRN PLAINS INTO WESTERN AND
NORTH CENTRAL NEBRASKA. THIS WILL RESULT IN HIGHS IN THE MID TO
UPPER 60S THIS AFTERNOON...WHICH IS A SMALL DECREASE IN THE LOWER
70S IN THE INHERITED FCST. HIGHS WERE LOWERED AS I AM ANTICIPATING
ADDITIONAL HIGH CLOUDINESS TO PUSH INTO THE FORECAST AREA LATER
THIS AFTERNOON FROM THE SRN ROCKIES. THIS CLOUDINESS IS IN ADVANCE
OF AN APPROACHING DISTURBANCE...WHICH WILL BEGIN TO IMPACT THE
FORECAST AREA LATER TONIGHT.
PRECIPITATION CHANCES WILL BEGIN TO INCREASE OVERNIGHT TONIGHT AS
MID LEVEL WAA BEGINS TO LIFT INTO THE CENTRAL PLAINS IN ADVANCE OF
AN APPROACHING UPPER LEVEL DISTURBANCE. ELEVATED INSTABILITY WILL
INCREASE OVERNIGHT PER H800 CALCULATED LI`S RANGE FROM -1 TO -3
OVERNIGHT ACROSS CENTRAL AND NORTHERN NEBRASKA. ADDITIONAL FORCING
FOR TSRAS WILL COME FROM THE DEVELOPMENT OF A 30 KT LLJET WHICH WILL
EXTEND FROM WESTERN KS INTO SWRN NEBRASKA AFTER 06Z TONIGHT.
COVERAGE OF TSRAS IS EXPECTED TO BE LIMITED THOUGH AS SURFACE DEW
POINTS WILL ONLY BE IN THE LOWER TO MID 40S. ATTM...NO SEVERE
THUNDERSTORMS ARE EXPECTED OVERNIGHT...AS LIFT AND AVAILABLE CAPE
WILL BE LIMITED.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 407 AM CDT MON MAY 6 2013
BY TUESDAY MORNING THERE REALLY WON/T BE MUCH MOVEMENT IN THE
PRIMARY UPPER LEVEL SYSTEMS ACROSS THE CONUS. THE UPPER LOW OVER
THE SOUTHEAST PART OF THE COUNTRY WILL HAVE MOVED INTO THE
CAROLINAS...WHILE THE SYSTEM OFF THE CALIFORNIA COAST WILL JUST BE
MOVING ONSHORE BY 12Z TUESDAY. ALSO...THE WEAK UPPER LOW NOW OVER
SOUTH DAKOTA WILL STAY STATIONARY THROUGH TUESDAY MORNING.
MODEL SOLUTIONS HAVE STARTED TO BECOME MORE IN LINE FOR TUESDAY.
THE SYSTEM OVER THE SOUTHEAST WILL SLOWLY LIFT NORTH ALONG THE
EAST COAST THROUGH THE WEEK...WHILE THE CALIFORNIA LOW MOVES
ONSHORE TUESDAY AND INTO THE GREAT BASIN TUESDAY NIGHT.
MEANWHILE...THE WEAK UPPER LOW OVER THE DAKOTAS WILL STAY IN THE
AREA THROUGH AT LEAST TUESDAY NIGHT AS THE NORTHERN STREAM STAYS
WELL TO THE NORTH LEAVING NOTHING TO KICK IT OUT OF THE AREA.
MEANWHILE...A WEAK SHORTWAVE TROUGH EJECTS OUT OF THE WEST COAST
TROUGH AND PUSHES INTO THE CENTRAL PLAINS. PRECIPITATION CHANCES
WILL INCREASE LATER TUESDAY AFTERNOON AND TUESDAY NIGHT AHEAD OF
THE SHORTWAVE TROUGH MOVING INTO THE AREA. MOISTURE WILL BE ON THE
RISE ON TUESDAY AHEAD OF THIS FEATURE AS WELL...WITH THE MODELS
BEING FAIRLY IN TUNE WITH EACH OTHER BRINGING IN 50 DEGREE
DEWPOINTS INTO THE EASTERN PARTS OF THE FORECAST AREA. THIS
MOISTURE ALONG WITH SOME COOLER TEMPERATURES ALOFT /THANKS TO THE
UPPER LOW HANGING AROUND/ WILL CAUSE THE AIR TO BE UNSTABLE FOR
THUNDERSTORMS MAINLY STARTING TUESDAY AFTERNOON. LOOKING FOR QUITE
A BIT OF CLOUD COVER THROUGH THE DAY TUESDAY AND WITH AT LEAST
PERIODIC SHOWERS AND THUNDERSTORMS...NOT EXPECTING TEMPERATURES TO
BE TOO WARM AND ACTUALLY COOLED THEM A FEW DEGREES FROM THE
PREVIOUS FORECAST.
MODEL AGREEMENT CONTINUES THROUGH THE DAY WEDNESDAY AS A SHORTWAVE
MOVING THROUGH THE NORTHERN STREAM DROPS FAR ENOUGH SOUTH TO CATCH
THE DAKOTA UPPER LOW AND FINALLY PUSH IT EASTWARD. AT THIS POINT
THE CALIFORNIA UPPER LOW WILL HAVE MOVED INTO THE FOUR CORNERS.
THIS MAKES WEDNESDAY LOOK DRIER THAN WAS PREVIOUSLY FORECAST AS
THE AREA SITS IN A SUBSIDENT REGION BEHIND THE PASSING UPPER LOW
AND TOO FAR AHEAD OF THE FOUR CORNERS LOW TO REALLY EXPECT MUCH
FOR PRECIPITATION. AT THIS POINT...DIDN/T GO COMPLETELY DRY FOR
WEDNESDAY...AS THERE IS STILL A LACK OF CONFIDENCE IN THE MODEL
SOLUTIONS. AT THIS POINT TRENDED PRECIPITATION FORECAST
LOWER...WITH THE BETTER CHANCES FOR RAIN ACROSS THE SOUTHERN PARTS
OF THE FORECAST AREA. IN TURN...WITH LESSER PRECIPITATION
EXPECTED...INCREASED TEMPERATURES A BIT FOR WEDNESDAY. THERE DOES
LOOK TO BE A WARM FRONT LOCATED SOMEWHERE ACROSS KANSAS ON
WEDNESDAY AFTERNOON...WHICH SHOULD BE THE FOCUS FOR STORM
DEVELOPMENT. INSTABILITY IS DECENT...AND SHEAR IS BETWEEN 35 AND
45KTS SO COULD SEE SOME STRONGER STORMS. THIS BEING SAID...CURRENT
THINKING IS THAT MOST OF THIS ACTIVITY WILL STAY SOUTH OF THE
LOCAL AREA...MAINLY IN FAR SOUTHERN NEBRASKA AND KANSAS. BUT IF
THIS BOUNDARY MEANDERS MAY NEED TO ADJUST THIS THINKING NORTHWARD.
AT THIS POINT MODEL DIVERGENCE BEGINS WITH HOW THE UPPER LOW TO
THE SOUTHWEST WILL PROGRESS. THE ECMWF AND GFS ARE FOR THE MOST
PART BOTH WEAKENING THE LOW AND DEVELOPING ANOTHER OVER NORTHWEST
MEXICO. THE GEM ON THE OTHER HAND QUICKLY PUSHES EVERYTHING TO THE
EAST. CONFIDENCE LESSENS WITH PRECIPITATION CHANCES FOR THURSDAY
AND FRIDAY...BUT THERE REMAINS SOME WEAK SIGNALS SO KEPT IT IN THE
FORECAST FOR NOW.
GOING INTO THE WEEKEND...A STRONG RIDGE BUILDS OVER THE WEST
COAST. IN TURN...AN UPPER LEVEL TROUGH DIGS SOUTH ACROSS THE
NORTHERN PLAINS AND GREAT LAKES REGION. THIS WILL PUSH A PRETTY
STRONG COLD FRONT ACROSS THE AREA...MOST LIKELY SOMETIME SATURDAY
MORNING. MAY HAVE A CHANCE FOR SOME SHOWERS WITH THE FRONTAL
PASSAGE...BUT THE MAIN IMPACT WILL BE AGAIN PUSHING THE NEAR
NORMAL TEMPERATURES SOUTHWARD...WITH TEMPERATURES AROUND 60 OR
LOWER POSSIBLE FOR SATURDAY. ALSO...WITH THE COLDER AND DRIER
AIRMASS ASSOCIATED WITH THIS SYSTEM...COULD ONCE AGAIN SEE LOWS
SUNDAY MORNING IN THE MID 30S OR EVEN LOWER IN SOME LOCATIONS. IN
BOTH CASES...DID NOT GO TO THE EXTREME AS THERE WILL LIKELY BE
SOME CHANGES IN MODEL SOLUTIONS OVER THE NEXT SEVERAL DAYS.
INSTEAD...JUST TRENDED COLDER FOR BOTH PERIODS. THE LONG TERM
MODELS ARE FAIRLY PROGRESSIVE WITH THE UPPER FLOW FOR THE WEEKEND
AND EARLY NEXT WEEK THOUGH SO THIS WOULD INDICATE THIS COLD SPELL
WILL BE QUITE SHORT LIVED...WITH HIGHS RECOVERING TO AROUND 70 FOR
SUNDAY AND POSSIBLY NEARING 80 BY MONDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 637 AM CDT MON MAY 6 2013
FOR THE KLBF TERMINAL...SCATTERED HIGH CLOUDINESS IS EXPECTED TODAY
AS AN UPPER LEVEL DISTURBANCE APPROACHES FROM THE SOUTHERN ROCKIES.
CIGS WILL LOWER TO 10000 TO 15000 FT TONIGHT. ISOLATED THUNDERSTORMS
ARE POSSIBLE ACROSS SOUTHWESTERN AND CENTRAL NEBRASKA OVERNIGHT
TONIGHT. WILL FORGO MENTION OF THUNDERSTORMS IN THE 12Z KLBF TAF AS
COVERAGE WILL BE ISOLATED. FOR THE KVTN TERMINAL...MAINLY CLEAR
SKIES ARE EXPECTED. SOME MID LEVEL CLOUDINESS WILL MOVE INTO
NORTHERN NEBRASKA LATER TONIGHT...WITH CIGS AROUND 15000 FT AGL.
WINDS WILL BE FROM THE SOUTH OR SOUTHEAST AT AROUND 10 KTS THROUGH
12Z TUESDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ007-010-
028-029.
&&
$$
SYNOPSIS...CLB
SHORT TERM...BROOKS
LONG TERM...BROOKS
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
515 AM CDT MON MAY 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 403 AM CDT MON MAY 6 2013
OVERNIGHT UPPER AIR ANALYSIS INDICATES A MID TO UPPER LEVEL OMEGA
PATTERN WITH MID TO UPPER LEVEL LOWS OVER THE WESTERN AND
SOUTHEASTERN CONUS...AND RIDGING OVER THE CENTRAL CONUS. MID AND
UPPER LEVEL JET ENERGY REMAINS RELEGATED WELL TO OUR SOUTH AND AS
A RESULT...MID AND UPPER LEVEL FLOW OVER THE CENTRAL PLAINS
REMAINS VERY WEAK. WATER VAPOR IMAGERY SHOWS THE TWO
AFOREMENTIONED MID LEVEL LOWS...WITH INCREASED VALUES OF MID LEVEL
MOISTURE WRAPPING AROUND THE SOUTHEASTERN CONUS LOW INTO PORTIONS
OF THE OHIO RIVER VALLEY AND THE MID MISSISSIPPI VALLEY...AND
INCREASED VALUES OF MID LEVEL MOISTURE ALSO NOTED OVER THE WESTERN
CONUS AHEAD OF THE WESTERN CONUS LOW. WATER VAPOR IMAGERY ALSO
INDICATES A SUBTLE MID LEVEL SHORT WAVE OVER THE SOUTHWESTERN
CONUS...PIVOTING TO THE SOUTHEAST OF THE WESTERN CONUS MID LEVEL
LOW. AT THE SURFACE A RIDGE OF HIGH BAROMETRIC PRESSURE EXISTS
FROM NORTH TO SOUTH ACROSS OUR CWA AND AS A RESULT...THE LOW LEVEL
WIND FIELD ACROSS OUR AREA REMAINS LIGHT. THE LIGHT LOW LEVEL WIND
FIELD...WORKING IN CONCERT WITH DECREASING LOW LEVEL DEWPOINT
DEPRESSIONS...HAS PROMOTED THE DEVELOPMENT OF FOG ACROSS MUCH OF
OUR AREA THIS MORNING.
GIVEN THE CURRENT FOG BEING OBSERVED ACROSS THE AREA...WILL
CONTINUE FOG MENTION IN THE FORECAST THROUGH 14Z THIS MORNING. AS
OF 09Z KODX...KHSI AND KAUH HAVE DROPPED TO 1/4SM WITH SEVERAL
OTHER SITE IN THE AREA ALSO DROPPING NEAR 1/4SM. GIVEN ALL
THIS...WENT AHEAD WITH A DENSE FOG ADVISORY...FOR LOCATIONS
GENERALLY EAST OF A KODX TO KEAR LINE AND NORTH OF HIGHWAY 6. THIS
FOG APPEARS TO BE VERY SHALLOW...BASED ON LAPS AND RAP ANALYSIS
POINT SOUNDINGS AS WELL AS OBSERVATION HERE AT THE OFFICE. AS A
RESULT...INCREASED DIABATIC HEATING AND RESULTANT INCREASING
BOUNDARY LAYER DEPTH AND MIXING SHOULD ALLOW THE FOG TO QUICKLY
DISSIPATE POST-SUNRISE...WITH FULL VISIBILITY EXPECTED AT MOST
SITES BY 14Z.
AN OVERALL LACK IN KINEMATIC FORCING IS EXPECTED TO KEEP OUR AREA
DRY TODAY. THE SUBTLE MID LEVEL SHORT WAVE...CURRENTLY OVER THE
SOUTHWESTERN CONUS...IS EXPECTED TO CONTINUE MOVING EAST/NORTHEAST
TODAY AND BY THIS EVENING...SHOULD BE MOVING ACROSS THE SOUTHERN
TO CENTRAL ROCKY MOUNTAIN RANGE. MID LEVEL THERMAL ADVECTION AND
RESULTANT OMEGA AHEAD OF THE SHORT WAVE TROUGH AXIS APPEARS AS
THOUGH IT WILL BE STRONG ENOUGH FOR PRECIPITATION PRODUCTION
ACROSS THE SOUTHERN TO CENTRAL HIGH PLAINS LATE THIS AFTERNOON
INTO THIS EVENING. SHORTLY AFTER SUNSET TONIGHT...A ~30KT 850MB
JET STREAK IS EXPECTED TO DEVELOP FROM SOUTH TO NORTH ACROSS THE
SOUTHERN AND CENTRAL HIGH PLAINS. THIS 850MB JET STREAK IS THEN
EXPECTED TO PROPAGATE EAST SOMEWHAT DURING THE OVERNIGHT HOURS AND
BY 12Z TUESDAY...THE EASTERN PERIPHERY OF THIS 850MB JET AXIS WILL
BRUSH UP AGAINST WEST/SOUTHWESTERN PORTIONS OF OUR CWA. LOW LEVEL
THERMAL ADVECTION ALONG THE 850MB JET STREAK AXIS APPEARS AS
THOUGH IT WILL ALLOW LATE AFTERNOON/EVENING PRECIPITATION ACROSS
THE HIGH PLAINS TO HOLD TOGETHER POST-SUNSET...AND MOVE INTO
WESTERN/SOUTHWESTERN PORTIONS OF OUR CWA 06-12Z TUESDAY. THIS IS A
SOLUTION SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL
GFS...EC AND SREF-MEAN. GIVEN THE MODEL AGREEMENT AND THE APPARENT
LIKELIHOOD THAT SOME LOCATIONS ACROSS OUR WEST/SOUTHWEST COULD
PICKUP UPWARDS OF A TENTH OF AN INCH OF PRECIPITATION...OPTED TO
INCREASE POPS INTO THE 40-50% RANGE ACROSS OUR FAR WEST/SOUTHWEST
06-12Z TUESDAY. LOCATIONS FATHER EAST/NORTHEAST ALSO HAVE POPS IN
PLACE FOR TONIGHT...ALBEIT SUBSTANTIALLY LOWER IN THE 20-30% RANGE
AS CONFIDENCE IS NOT NEARLY AS HIGH THAT FAR EAST WITH THE 850MB
JET STREAK AXIS EXPECTED TO REMAIN FARTHER WEST.
MOISTURE FLUX ALONG THE 850MB JET STREAK AXIS...AS WELL AS THE
700MB JET STREAK AXIS...WORKING IN CONCERT WITH INCREASING MID
LEVEL LAPSE RATES WITH THE APPROACH OF THE SUBTLE MID LEVEL SHORT
WAVE...IS EXPECTED TO PROVIDE INCREASING POTENTIAL INSTABILITY
ACROSS OUR AREA TONIGHT. THE NAM IN PARTICULAR SUGGESTS PARCELS
ROOTED TO BETWEEN 850MB AND 750MB WILL HAVE 50-100J/KG OF CAPE TO
WORK WITH AND CIN RANGING BETWEEN NEAR-ZERO AND AROUND -20J/KG.
GIVEN ALL THIS...ISOLATED CONVECTION CERTAINLY SEEMS POSSIBLE
EMBEDDED WITHIN THE STRATIFORM RAIN EVENT OCCURRING ALONG THE LOW
LEVEL JET AXIS. GIVEN ALL THIS WENT AHEAD AND ADDED ISOLATED
THUNDER MENTION TO THE FORECAST FOR OUR CWA FOR TONIGHT.
THE SURFACE RIDGE CURRENTLY OVER THE AREA IS EXPECTED TO PUSH EAST
LATER TODAY...ALLOWING FOR WEAK LOW LEVEL RETURN FLOW ACROSS MUCH
OF OUR AREA BY THIS AFTERNOON. SUBTLE LOW LEVEL WARM AIR
ADVECTION...AS WELL AS INCREASED DIABATIC HEATING...WHEN COMPARED
TO SUNDAY SHOULD ALLOW FOR A WARMER DAY ACROSS OUR CWA TODAY. AN
AFTERNOON HIGH TEMPERATURE IN THE UPPER 60S TO LOWER 70S IS
FORECAST FOR MOST LOCATIONS FOR TODAY AS A RESULT. INCREASING
CLOUD COVER...POSSIBLE PRECIPITATION...AND CONTINUED SOUTHEASTERLY
LOW LEVEL FLOW SHOULD PRESENT A WARMER OVERNIGHT LOW TEMPERATURE
TONIGHT WHEN COMPARED TO EARLY THIS MORNING. A TUESDAY MORNING LOW
TEMPERATURE IN THE MID TO UPPER 40S IS FORECAST FOR MOST LOCATIONS
ACROSS OUR CWA AS A RESULT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 403 AM CDT MON MAY 6 2013
TUESDAY THROUGH SUNDAY. MAIN FORECAST CONCERNS WILL BE CHANCES FOR
SHOWERS AND THUNDERSTORMS TUESDAY THROUGH SATURDAY AND
TEMPERATURES.
AN UNSETTLED PATTERN WILL BE FOUND ACROSS THE CENTRAL PLAINS FOR
TUESDAY THROUGH SATURDAY. A WEAK RIDGE SETS UP BETWEEN A STRONG
UPPER LEVEL LOW TO THE WEST AND ANOTHER TO THE EAST. DESPITE THE
RIDGE...THERE WILL BE SEVERAL RELATIVELY WEAK UPPER LEVEL LOW
PRESSURE SYSTEMS THAT WILL AFFECT THE AREA FOR THE TUESDAY THROUGH
SATURDAY PERIOD. DO NOT EXPECT THAT IT WILL BE RAINING ALL OF THE
TIME FOR EACH OF THESE PERIODS...BUT THERE IS A CHANCE FOR SHOWERS
AND THUNDERSTORMS ON AND OFF THROUGH THE PERIOD. THE STRONGEST
UPPER LEVEL LOWS THAT MOVE THROUGH THE AREA WILL BE FOR TUESDAY
AND TUESDAY NIGHT AND AGAIN WEDNESDAY NIGHT. THESE WILL BRING THE
BEST CHANCES FOR PRECIPITATION. THE MUCAPE FOR TUESDAY AFTERNOON
AND EVENING WILL REACH AROUND 750 J/KG WHICH SHOULD BE ENOUGH FOR
SOME ISOLATED SEVERE WEATHER...BUT WEDNESDAY AFTERNOON AND EVENING
MUCAPE VALUES APPROACH 2500 J/KG WHICH WOULD INDICATE A BETTER
CHANCE FOR SOME SEVERE STORMS. THERE ARE STILL SOME DIFFERENCES IN
THE MODELS AND WILL HAVE TO WATCH TO SEE HOW MUCH CHANGE THERE IS
OVER THE NEXT COUPLE DAYS.
FOR THURSDAY THROUGH SATURDAY THE UPPER LEVEL LOW IN THE WESTERN
CONUS WILL DRIFT TO THE EAST AND INTO THE PLAINS. THIS WILL
CONTINUE TO BRING CHANCES FOR SHOWERS WITH SOME ISOLATED
THUNDERSTORMS. MU CAPE VALUES DECREASE TO LESS THAN 200 J/KG.
TEMPERATURES SHOULD REMAIN AROUND NORMAL FOR THIS TIME OF YEAR
THROUGH FRIDAY...BUT AS A COLD FRONT MOVES SOUTH INTO THE AREA ON
SATURDAY EXPECT SOME SHOWERS AND THUNDERSTORMS BEHIND THE FRONT
AND TEMPERATURES WILL COOL OFF A FEW DEGREES. A COOL SURFACE HIGH
PRESSURE SYSTEM SETTLES INTO THE REGION FOR SATURDAY NIGHT INTO
SUNDAY AND TEMPERATURES WILL REMAIN A BIT COOLER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 515 AM CDT MON MAY 6 2013
LIFR TO VLIFR CONDITIONS EXPECTED UNTIL 14Z...WITH VFR CONDITIONS
EXPECTED BY 14 AND BEYOND.
DENSE FOG HAS INFILTRATED MUCH OF SOUTH CENTRAL NEBRASKA THIS
MORNING WITH SEVERAL SITES NEAR KGRI AT OR BELOW 1/4SM. GIVEN THE
VISIBILITY TRENDS AT KGRI THROUGH THE PAST COUPLE HOURS...OPTED TO
GO WITH PREVAILING LIFR VISIBILITY THROUGH 14Z...WITH TEMPO VLIFR
VISIBILITY ALSO THROUGH 14Z. THIS FOG APPEARS TO BE VERY
SHALLOW...BASED ON LAPS AND RAP ANALYSIS POINT SOUNDINGS AS WELL
AS OBSERVATION HERE AT THE OFFICE. AS A RESULT...INCREASED
DIABATIC HEATING AND RESULTANT INCREASING BOUNDARY LAYER DEPTH AND
MIXING SHOULD ALLOW THE FOG TO QUICKLY DISSIPATE POST-
SUNRISE...WITH FULL VISIBILITY EXPECTED BY 14Z. SCATTERED MID TO
HIGH LEVEL CLOUDS WILL CONTINUE AT KGRI THROUGH THE NEXT 24
HOURS...ALTHOUGH A BROKEN DECK NEAR 5000FT AGL IS POSSIBLE TOWARDS
THE END OF THE TAF PERIOD. THE PRESENCE OF A SURFACE RIDGE WILL
KEEP THE SURFACE WIND LIGHT AND VARIABLE THIS MORNING...BEFORE
BECOMING MORE ESTABLISHED FROM THE SOUTHEAST THIS AFTERNOON. THERE
IS A CHANCE OF MEASURABLE PRECIPITATION AND CONVECTIVE ACTIVITY
06Z-12Z TUESDAY...HOWEVER THE PROBABILITY OF SUCH ACTIVITY BEING
REALIZED AT KGRI IS TOO LOW FOR INSERTION INTO THE TAF AT THIS
TIME.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR NEZ039>041-
046>049-061>064-074>077.
KS...NONE.
&&
$$
SHORT TERM...BRYANT
LONG TERM...JCB
AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS PUEBLO CO
321 PM MDT MON MAY 6 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 308 PM MDT MON MAY 6 2013
UPPER DISTURBANCE LIES JUST TO THE SOUTH OF CO WITH BANDS OF
CONVECTION ACROSS NORTHERN NEW MEXICO LIFTING NORTHWARD AHEAD OF
THIS FEATURE. WE`VE HAD PERSISTENT -SHRASN ACROSS THE MOUNTAIN
AREAS TODAY...PARTICULARLY ALONG THE CONTDVD WHERE KMYP AND KCPW WEB
CAMS CONTINUE TO SHOW WET SNOW FALLING. KALS HAS ALSO PICKED UP A
BRIEF RAIN SHOWER...AND EVEN KTAD REPORTED SOME LIGHT RAIN WITH A
BAND THAT MOVED OFF THE MOUNTAINS EARLIER THIS AFTERNOON.
MEANWHILE...SFC DEW POINTS ACROSS THE PLAINS HAVE BEEN SLOW TO COME
UP WITH READINGS STILL IN THE LOWER TO MID 20S FOR MOST AREAS.
AS THE SHORTWAVE CONTINUES TO TRACK TO THE NORTH ACROSS THE AREA
THIS EVENING...WILL CONTINUE HIGH POPS ACROSS THE MOUNTAINS WITH
AXIS OF HIGHEST POPS SHIFTING INTO THE NORTH CENTRAL MOUNTAINS
THROUGH THE EVENING. ACROSS THE PLAINS WILL KEEP GENERALLY ISOLATED POPS
IN THE FCST AS HRRR LOOKS OVERDONE WITH QPF FIELDS GIVEN THE SLOW
REBOUND IN SFC DEW POINTS. THE TWO DIVIDES...PALMER AND
RATON...HAVE THE BEST CHANCE AT SEEING SOME MEASURABLE
PRECIPITATION...SO WILL HOLD ON TO SOME SCT POPS FOR THESE AREAS.
WILL BE CONTINUING TO WATCH THE WALDO CANYON BURN SCAR FOR
RAINFALL. MOST LIKELY SCENARIO IS FOR QPF AMOUNTS TO RANGE UP TO
.10...WHICH IS BELOW FLOOD ADVISORY THRESHOLDS. HOWEVER IF A
STRONGER CELL DEVELOPS...THERE COULD BE SOME LOCAL AMOUNTS APPROACH
.20.
AS THE DISTURBANCE LIFTS NORTHWARD...SHOULD SEE IMPROVING CONDITIONS
SPREAD FROM SOUTH TO NORTH OVERNIGHT WITH SOME CLEARING TAKING PLACE
TOWARDS MORNING. HAVE POPS DROPPING INTO THE ISOLATED CATEGORY
OVERNIGHT ACROSS THE CENTRAL AND SOUTHWEST MOUNTAINS AS FORCING IS
WEAK AND WE LOOSE CONVECTIVE INGREDIENT.
STILL LOOKS LIKE THE WARMEST DAY IS ON TAP FOR TUESDAY. ALTHOUGH
SFC DEW POINTS WILL LIKELY RISE INTO THE 30S OVERNIGHT...THEY FALL
AGAIN ACROSS THE SOUTHEAST PLAINS INTO THE 20S...WITH LCLS IN MODEL
SOUNDINGS AROUND H6. FOR THAT REASON...THINK THAT SUB CLOUD DRY
LAYER WILL KEEP ANY RAINFALL ON THE WALDO BURN SCAR FROM REACHING
FLOOD ADVISORY CRITERIA ONCE AGAIN...WITH AMOUNTS LIKELY TO REMAIN
UNDER .10. BUT WITH MORE SUNSHINE ON TUESDAY RESULTING IN BETTER
POTENTIAL INSTABILITY...AND NAM12 HINTING AT A BOUNDARY STALLING
ALONG THE PALMER DIVIDE IN THE AFTERNOON...WALDO WILL NEED TO BE
MONITORED AS CELLS COULD POTENTIALLY BE STRONGER. OVER THE MOUNTAIN
AREAS...KEPT POPS IN THE SCATTERED RANGE AS WE APPEAR TO LACK ANY
STRONG FORCING ALOFT FOR MORE WIDESPREAD PCPN. OTHERWISE...HIGH
TEMPERATURES SHOULD TOP OUT IN THE 70S ACROSS THE PLAINS...WITH 60S
FOR THE VALLEYS...AND GENERALLY 40S AND 50S FOR THE MOUNTAINS. -KT
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 308 PM MDT MON MAY 6 2013
INCREASING CONCERNS FOR HEAVIER RAIN POTENTIAL(LOWER ELEVATION
SHOWERS AND THUNDERSTORMS)...INCLUDING OVER THE WALDO CANYON
BURN SCAR(ESPECIALLY FROM WEDNESDAY INTO THURSDAY) AS WELL AS
INCREASING STRONG TO SEVERE WEATHER THREAT OVER PORTIONS OF THE
SOUTHEASTERN COLORADO PLAINS FROM WEDNESDAY INTO WEDNESDAY NIGHT
AND HIGHER ELEVATION SNOWS ARE PRIMARY LONGER TERM METEOROLOGICAL
ISSUES.
RECENT LONGER TERM COMPUTER SIMULATIONS SUGGEST THAT CLOSED UPPER
LOW CENTERED OVER FAR SOUTHERN NEVADA AT 00Z WEDNESDAY MOVES INTO
THE FOUR CORNERS REGION BY 00Z THURSDAY WITH LATEST ECMWF SOLUTION
SLOWLY MOVING THE CLOSED UPPER LOW ACROSS SOUTHERN COLORADO INTO
WESTERN KANSAS BY 06Z FRIDAY WHILE LATEST GFS SUGGESTS THAT CLOSED
UPPER LOW WILL REMAIN IN THE VICINITY OF THE FOUR CORNERS REGION
THROUGH THURSDAY BEFORE DROPPING UPPER LOW SOUTH INTO FAR
SOUTHEASTERN ARIZONA BY 00Z SATURDAY. IN ADDITION...NORTHERLY
SURGES(CAPABLE OF ENHANCING PRECIPITATION POTENTIAL) ARE PROJECTED
TO MOVE ACROSS PRIMARILY EASTERN SECTIONS OF THE CWFA TUESDAY
NIGHT...WEDNESDAY AND THEN AGAIN ON SATURDAY.
BOTH ECMWF AND GFS SOLUTIONS GENERATE HEALTHY AMOUNTS OF
PRECIPITATION OVER THE FORECAST DISTRICT THROUGH THURSDAY
NIGHT...WITH OF COURSE THE GFS MODEL MUCH MORE AGGRESSIVE WITH
RESPECT TO POTENTIAL TOTAL PRECIPITATION AMOUNTS.
PRECIPITATION...HEAVY AT TIMES...WILL BE POSSIBLE OVER MANY
PORTIONS OF THE FORECAST DISTRICT FROM TUESDAY NIGHT INTO AT
LEAST THURSDAY NIGHT AND FLOOD WATCHES MAY BECOME NECESSARY FOR
AREAS SUCH AS THE WALDO CANYON BURN SCAR(ESPECIALLY FROM WEDNESDAY
INTO THURSDAY) IF METEOROLOGICAL TRENDS CONTINUE. WFO PUEBLO WILL
CONTINUE TO MONITOR CLOSELY AND ISSUE HIGHLIGHTS/ADVISORIES
AND/OR HYDRO WARNINGS IF/AS NEEDED.
ANOTHER LONGER TERM CONCERN WILL BE THE POTENTIAL FOR STRONG TO
SEVERE CONVECTION OVER PORTIONS OF THE SOUTHEASTERN COLORADO
PLAINS...ESPECIALLY FROM WEDNESDAY INTO WEDNESDAY NIGHT AS DEEPER
ATMOSPHERIC MOISTURE...LOCALIZED 0 TO 6 KM SHEARS AROUND 30
KNOTS...LOCALIZED CAPES AROUND 2100 J/KG AND LOCALIZED LIS AROUND
-8C RESPECTIVELY ARE ANTICIPATED OVER PORTIONS(ESPECIALLY FAR
EASTERN SECTIONS) OF THE SOUTHEASTERN COLORADO PLAINS. AS
ALWAYS...WFO PUEBLO WILL CONTINUE TO MONITOR CLOSELY AND ISSUE
SEVERE WEATHER PRODUCTS AS NEEDED.
ACCUMULATING SNOW IS ALSO EXPECTED AT TIMES OVER HIGHER TERRAIN
AREAS FROM TUESDAY NIGHT INTO LATER THIS WEEK. WINTER WEATHER
HIGHLIGHTS MAY BECOME NECESSARY OVER HIGHER TERRAIN AREAS DURING
THIS TIME-FRAME(ESPECIALLY OVER PUBLIC ZONES 58/60/66/68/73/75/81
AND 82).
IMPROVING METEOROLOGICAL CONDITIONS IN THE FORM OF WARMING
TEMPERATURES AND DECREASING POPS ARE THEN ANTICIPATED FROM LATER
THIS WEEKEND INTO EARLY NEXT WEEK. COOLEST TEMPERATURES DURING THE
LONGER TERM ARE EXPECTED TUESDAY AND WEDNESDAY WHILE WARMEST LONGER
TERM TEMPERATURES ARE PROJECTED SUNDAY AND NEXT MONDAY. FINALLY...
STILL ANTICIPATE THAT LOW-GRADE GRADIENT WINDS SHOULD CONTINUE
OVER THE FORECAST DISTRICT DURING THE LONGER TERM.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 308 PM MDT MON MAY 6 2013
UPPER DISTURBANCE WILL SPREAD ISOLATED TO NUMEROUS
SHOWERS ACROSS SOUTH CENTRAL AND SOUTHEAST CO THROUGH THE
EVENING...WITH HIGHEST COVERAGE ACROSS THE MOUNTAIN AREAS. MOUNTAIN
AREAS ALONG THE CONTDVD WILL CONTINUE TO SEE IFR CONDITIONS WITH
LOCAL LIFR AND MTN OBSCURATIONS ACROSS THE HIGHER PEAKS IN -SHSN.
THE SOUTHEAST MTS COULD SEE SOME IFR CONDITIONS AT TIMES THIS
EVENING WITH -SHRASN AND EVEN SOME ISOLATED -TS. AS FOR THE TAF
SITES...KALS WILL CONTINUE TO SEE THE POTENTIAL FOR -SHRA THROUGH
THE EARLY EVENING WITH VFR TO MVFR CIGS AT TIMES. KCOS AND KPUB COULD
SEE A PASSING SHOWER AFTER 21Z...HOWEVER PROBABILITY IS NOT AS GREAT
AS LOW LEVEL MOISTURE HAS BEEN SLOW TO RETURN. CIGS SHOULD STAY IN
THE VFR CATEGORY...THOUGH HIGHER TERRAIN NORTH AND WEST OF KCOS
COULD SEE SOME MVFR CIGS IN -SHRA. CLEARING CONDITIONS CAN BE
EXPECTED OVERNIGHT WITH A SUNNIER START TO THE DAY ON TUESDAY.
ISOLATED TO SCATTERED AFTERNOON -TSRA HIGHER MTN -SHSN WILL DEVELOP
OVER THE MOUNTAINS AGAIN WITH MVFR TO IFR CIGS. TAF SITES ARE MORE
LIKELY TO REMAIN DRY WITH VFR CONDITIONS. KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1047 AM MDT MON MAY 6 2013
.UPDATE...
&&
.SHORT TERM...CURRENT FORECASTS LOOK ON TRACK. WATER VAPOR LOOPS
SHOWING SHORTWAVE MOVING INTO THE FOUR CORNERS REGION WITH
ABUNDANT MOISTURE SPREADING NORTHEAST ACROSS MOUNTAINS. RADAR
SHOWING SOME SHOWERS OVER PARK AND SUMMIT COUNTIES. SHOWERS APPEAR
LIGHT BASED ON WEB CAMS. CURRENT TEMPERATURES SUGGESTING PERHAPS A
MIX OF RAIN AND SNOW OVER SOUTH PARK WITH SNOW OVER THE HIGHER
ELEVATIONS. MODELS SHOW THIS SHORTWAVE MOVING NORTHEAST ACROSS THE
AREA DURING THE LATE AFTERNOON AND EVENING... WITH SHOWERS
BECOMING MORE WIDESPREAD OVER THE MOUNTAINS. SOME SNOW POSSIBLE
AROUND 11000 FEET...WITH MINIMAL ACCUMULATION. MODELS DO DELAY THE
ONSET OF THE SHOWERS ACROSS THE PLAINS UNTIL AFTER 21Z. BUT WITH
THE INCREASING LIFT AHEAD OF THE SHORTWAVE... IT IS POSSIBLE A FEW
SHOWERS COULD SPREAD ACROSS THE URBAN CORRIDOR AND PALMER DIVIDE A
BIT EARLIER. CURRENT FORECAST SHOWS THIS TREND...AND SEEMS MORE
REASONABLE. AIRMASS TO BECOME MORE UNSTABLE DURING THE AFTERNOON
WITH A FEW THUNDERSTORMS POSSIBLE. LATEST RAP DOES SHOW SOME
VERTICAL SHEAR ACROSS THE PLAINS WITH SOUTHEAST SURFACE FLOW AND
SOUTHWEST TO WEST FLOW ALOFT. BUT THE FLOW ALOFT LOOKS WEAK AND
DOESN`T APPEAR ADEQUATE FOR SEVERE STORMS. A FEW STORMS SOUTHEAST
AND EAST OF DENVER COULD BECOME STRONG ENOUGH TO PRODUCE SMALL
HAIL AND GUSTY WINDS ALONG WITH BRIEF HEAVY RAIN LATE THIS
AFTERNOON OR EARLY EVENING WITH PASSAGE OF THE SHORTWAVE.
.AVIATION...WINDS HAVE BECOME LIGHT NORTHWEST ACROSS THE AREA
AIRPORTS...SHOULD SHIFT TO THE NORTHEAST AROUND 18Z WITH SPEEDS
AROUND 8 KTS. WINDS TO BECOME EASTERLY AROUND 22Z WITH SPEEDS
INCREASING TO 15 KTS...COULD BE A BIT MORE SOUTHEAST AT KDEN AND
KAPA. SCATTERED SHOWERS ALONG WITH ISOLATED STORMS WILL DEVELOP
IN THE AREA AFTER 18Z. BEST CHANCE FOR STORMS AFFECTING THE AREA
AIRPORTS STILL LOOKS BETWEEN 22Z AND 02Z. CONFIDENCE NOT HIGH
ENOUGH FOR A TEMPO TSRA GROUP AT THIS TIME...WILL GO WITH VCTS FOR
NOW. ALSO A SLIGHT CHANCE FOR CEILINGS AROUND 6000 FEET DURING
THIS TIME FRAME...WILL LEAVE IN A TEMPO GROUP. SLIGHT CHANCE FOR
STORMS TO PRODUCE SMALL HAIL AND WIND GUSTS TO 30 KTS...MAINLY
SOUTHEAST OF KDEN AND KAPA.
&&
.HYDROLOGY...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS EXPECTED
THROUGH THE AFTERNOON AND EARLIER. SLIGHT CHANCE OF THE HEAVIER
SHOWERS AND STORMS TO PRODUCE UP TO A QUARTER OF AN INCH OF RAIN
IN ABOUT 45 MINUTES. THREAT OF SIGNIFICANT RUNOFF DUE TO THE
RAINFALL STILL APPEARS LOW.
&&
.PREV DISCUSSION... /ISSUED 441 AM MDT MON MAY 6 2013/
.CORRECTION FOR MISSING WORDS..
SHORT TERM....FAIRLY STRONG AND WELL DEFINED VORT LOBE/SHORTWAVE
TROUGH SWINGING NORTHEASTWARD AROUND THE SOUTHEAST SIDE OF THE
CLOSED UPPER LOW SPINNING OFF THE NORTHERN CALIFORNIA COAST WILL
BE THE PRINCIPLE WEATHER MAKER FOR NORTH CENTRAL AND NORTHEAST
COLORADO THIS AFTERNOON AND EVENING. EXTENSIVE CLOUD BAND
ASSOCIATED WITH THIS FEATURE PRESENTLY OVER NORTHEAST ARIZONA/
WESTERN NEW MEXICO IS PROGGED TO REACH THE SOUTHWEST EDGE OF THE
FORECAST AREA BY AROUND MIDDAY/18Z. PRIOR TO ARRIVE...WITH PLENTY
OF MID AND HIGH LEVEL MOISTURE OUT AHEAD OF IT...SHOULD SEE A
STEADY INCREASE IN CLOUD COVER OVER THE ENTIRE AREA THROUGH THE
MORNING HOURS. IN ADDITION RELATIVELY LIGHT WEST-NORTHWEST
700-500MB FLOW OVER THE AREA ATTM SHOULD BECOME PROGRESSIVELY MORE
SOUTHWESTERLY THRU THE MORNING...THEN SOUTHEASTERLY THIS AFTERNOON
WITH THE SHORTWAVE TROUGH NEARING. ITS AT THIS TIME WHEN WE SHOULD
SEE SHOWERS DEVELOPING OVER AND NEAR THE FRONT RANGE WITH AN
INCREASE IN LOW AND MID-LEVEL MOISTURE. HOWEVER...ACCORDING TO THE
WRF..NAM AND GFS MODELS...WOULD NOT EXPECT TO SEE SHOWERS AND
THUNDERSTORMS FORMING ON THE PLAINS UNTIL LATE THIS AFTERNOON OR
PERHAPS EARLY THIS EVENING. THAT/S WHEN MODEL POP AND QPF GUIDANCE
NUMBERS PEAK. MEANWHILE IN THE HIGH COUNTRY...ALREADY SEEING
ISOLATED SNOW SHOWERS UP ALONG THE CONTINENTAL DIVIDE PRODUCING
LITTLE OR NO SNOW ACCUMULATION. SHOWERS WILL BECOME MORE WIDESPREAD
BY THIS AFTERNOON WITH LIGHT SNOW ACCUMULATION POSSIBLE ABOVE 10
THOUSAND FEET BY LATE THIS EVENING. ATMOSPHERE ALSO EXPECTED TO
BECOME SUFFICIENTLY UNSTABLE TO PRODUCE AT LEAST ISOLATED
THUNDERSTORMS IN THE HIGH COUNTRY. SAME GOES FOR THE MTN VALLEYS AND
NORTHEAST PLAINS. STABILITY AND VERTICAL SHEAR ON PLAINS ACCORDING
TO MODELS...DO NOT APPEAR ADEQUATE FOR SEVERE T-STORMS...BUT WE
COULD SEE A FEW STORM CELLS...ROUGHLY SOUTH OF A BRIGGSDALE TO
DENVER LINE...PRODUCING SMALL HAIL...BRIEF HEAVY RAIN AND STRONG
GUSTY WINDS WITH PASSAGE OF THE SHORTWAVE LATE THIS AFTERNOON/EARLY
THIS EVENING.
BY LATE EVENING...PRECIP WILL QUICKLY DIMINISH FROM SOUTHWEST TO
NORTHEAST AS THE WAVE EXITS THE AREA. ALTHOUGH THERE SHOULD STILL BE
A FAIR AMOUNT OF CLOUD AROUND WITH A MOIST SOUTHWESTERLY FLOW OVER
THE AREA. HIGH TEMPERATURES TODAY A FEW DEGS WARMER THAN YESTERDAY
WITH THE MODEST WARMING ALOFT AHEAD OF THE SHORTWAVE. SEE LITTLE OR
NO CHANGE IN OVERNIGHT TEMPERATURES.
LONG TERM...THIS UPCOMING WEEK WILL BE CHARACTERIZED AS UNSETTLED
WITH RATHER COOL TEMPERATURES AND SHOWERY CONDITIONS. THE MAIN
WEATHER FEATURE WILL BE A BROAD LOW PRESSURE SYSTEM WHICH IS NOW
OFF THE NORTHERN CALIFORNIA COAST. BY TUESDAY...MODEL CONSENSUS
HAS THE LOW SLOWLY MOVING INLAND INTO SOUTHERN NEVADA AND THEN
INTO THE 4 CORNERS AREA ON WEDNESDAY. LONG RANGE MODELS BEGIN TO
DIVERGE ON THE TRACK AFTER WEDNESDAY AS THE GFS IS THE SLOWEST
MODEL AND NOW ACTUALLY RETROGRADES THE LOW BACK INTO THE DESERT
SOUTHWEST ON FRIDAY...WHILE THE FASTER EUROPEAN AND CANADIAN RUNS
MOVE THE WEAKENING LOW INTO THE CENTRAL PLAINS. THIS A BIT OF A
FLIP FLOP BETWEEN THE EUROPEAN AND GFS FROM A FEW RUNS AGO.
AS FOR THE DETAILS...TUESDAY WILL HAVE WEAK DESCENT IN THE WAVE OF
MONDAY NIGHTS EXITING WAVE WITH LOWER POPS FOR EARLY IN THE DAY ON
TUESDAY. THERE WILL BE ENOUGH LINGERING MOISTURE FOR SCATTERED
SHOWERS THOUGH ON TUESDAY AFTERNOON/EVENING. THE CHANCES OF RAIN
INCREASE ON WEDNESDAY AND WEDNESDAY NIGHT AS COLORADO WILL BE
UNDER INCREASING ASCENT FROM THE LOW AND DEEPENING EASTERLY FLOW.
MOST OF THE MODEL QPF OUTPUT SHOWING 1-2 INCHES OF RAIN OVER
PORTIONS OF THE NORTHEAST PLAINS. GFS HAS EVEN SOME HIGHER AMOUNTS
BUT THIS SEEMS OVERDONE. BY FRIDAY...THE FLOW WILL BECOME MORE
NORTH TO NORTHWEST WITH ADDITIONAL ENERGY TO EFFECT COLORADO
FRIDAY AND EARLY SATURDAY. FINALLY BY LATE SATURDAY AND SUNDAY A
DRIER AIRMASS BEGINS TO WORK IN FROM THE NORTHWEST WITH HIGH
PRESSURE BUILDING ALOFT.
AVIATION...VFR CONDITIONS ANTICIPATED AT DENVER AREA AIRPORTS
THROUGH 21Z TODAY. AFTER 21Z...SCATTERED RAIN SHOWERS AND ISOLATED
THUNDERSTORMS EXPECTED TO DEVELOP IN THE AREA. THERE IS A SLIGHT
CHANCE THAT STORMS BETWEEN 22Z AND 02Z COULD PRODUCE SMALL
HAIL...WIND GUSTS TO 30 KTS AND BRIEF HEAVY RAINFALL.
HOWEVER...AREAS EAST AND SOUTHEAST OF THE DENVER AREA HAVE A
BETTER CHANCE OF THIS OCCURRING. COULD SEE CIGS LOWERING TO
5000-6000 FT AGL WITH PASSING SHOWERS. CONDITIONS WILL IMPROVE
DURING THE EVENING WITH VFR CONDITIONS AND AN END TO PRECIPITATION
BY 21Z OR 22Z IN THE DENVER AREA.
HYDROLOGY...THE HEAVIER SHOWERS AND ISOLATED THUNDERSTORMS LATE
THIS AFTERNOON WILL HAVE THE POTENTIAL TO PRODUCE UP TO A QUARTER
INCH OF RAIN IN 45 MINUTES. AT THIS TIME...THE THREAT OF HEAVY
RUNOFF DUE TO THIS RAINFALL APPEARS LOW.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....ENTREKIN
AVIATION...D-L
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
145 PM EDT MON MAY 6 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN IN CONTROL OF OUR WEATHER THROUGH
WEDNESDAY MORNING. LOW PRESSURE APPROACHING FROM THE SOUTH WILL
BRING SCATTERED SHOWERS TO THE AREA LATE WEDNESDAY THROUGH FRIDAY.
ANOTHER LOW PRESSURE SYSTEM MOVES IN FROM THE WEST OVER THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
130 PM UPDATE...NO CHANGES TO THE GOING FORECAST AT THIS TIME OTHER
THAN TO ADD AREAS OF DENSE FOG IN AT THE COAST FOR TONIGHT.
1030 AM UPDATE...MINOR ADJUSTMENTS BASED ON LATEST TRENDS IN
OBSERVATIONAL DATA. FOG/STRATUS HAS BURNED OFF OVER LAND...HOWEVER
IT IS EXPECTED TO COME BACK IN...POSSIBLY AS EARLY AS LATE AFTERNOON
ON THE MID COAST...AND THEN THE REST OF THE COAST THIS EVENING.
TEMPS ON TRACK...LOWERED A BIT ON THE IMMEDIATE COAST.
PREVIOUSLY...
UPDATE...AS EXPECTED STRATUS IS ON THE DOORSTEP OF SRN NH ATTM.
APPEARS AS THOUGH IT WILL NOT MAKE IT MUCH FARTHER N...HOWEVER
VALLEY FOG IS PREVALENT ALONG THE COAST. THIS IS COVERED WELL IN
THE GRIDS...SO HAVE MAINLY USED CURRENT OBS TO ADJUST TEMPS FOR
THE NEXT SEVERAL HRS. HAVE ALSO USED THE LATEST HRRR TO REFINE
WIND FORECAST FOR THE SEA BREEZE.
PREVIOUS DISCUSSION...PERSISTENCE CONTINUES TO RULE THE FORECAST
IN THE NEAR TERM. HIGH PRES CENTERED INVOF NOVA SCOTIA REMAINS IN
CONTROL OF THE REGION. BEING CLOSER TO THE RIDGE AXIS...THE
COASTAL AREAS ARE SEEING SOME OF THE BEST RADIATIONAL COOLING AS A
RESULT. HAVE LEANED ON BIAS CORRECT MOS FOR MIN TEMPS...SEEING AS
THIS STRETCH OF WX HAVE PROVIDED SUFFICIENT DATA AND SIMILAR
CONDS.
KEEPING AN EYE ON COASTAL STRATUS OVER SRN NEW ENGLAND EDGING NWD.
TRACKING ITS CURRENT SPEED...IT WOULD ARRIVE OVER SRN NH AND SWRN
ME NEAR 10 TO 12Z. HAVE SOME HINTS OF IT IN THE GRIDS...BUT NOT
CONFIDENT IT TOTALLY MAKES IT TONIGHT. WILL HAVE TO WATCH MORE FOR
PATCHY FOG IN THE LOW LYING AREAS AS TEMPS BOTTOM OUT.
EXPECTED ANOTHER NICE DAY TODAY...AS TEMPS WARM QUICKLY IN DRY
CONDS. HIGHS WILL CLIMB WELL INTO THE 70S INLAND...WITH SEA
BREEZE/SLY FLOW KEEPING THE COAST CLOSER TO 60.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS RIDGE AXIS CONTINUES TO SLIDE EWD...MORE AND MORE SLY FLOW WILL
HELP TRANSPORT LLVL MOISTURE NWD. NAM IS NOT AS BULLISH AS
ECMWF/GFS/CMC...BUT GIVEN THE GRADUAL NWD DISPLACEMENT EACH NIGHT
EXPECT THAT IT SHOULD REACH THE COAST TONIGHT. INLAND AREAS WILL
REMAIN UNDER CLEAR SKIES.
STRATUS COULD STIFLE EARLY WARMING ALONG THE COAST TUE...BUT
EXPECT ANOTHER PLEASANT DAY WITH HIGHS IN THE 60S ALONG THE COAST
AND 70S TO NEAR 80 INLAND.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
EXTREMELY DRY PATTERN FOR THIS TIME OF THE YEAR WILL GRADUALLY
BECOME MORE SEASONAL AS WE HEAD INTO THE EXTENDED PORTION OF THE
FORECAST. SLOW MOVING...CUTOFF...UPPER LEVEL LOW WILL SLOWLY MOVE
NORTHEAST...WEAKENING AS IT APPROACHES NEW ENGLAND. THIS SYSTEM WILL
ALLOW SCATTERED SHOWERS TO ENTER FAR SOUTHERN AREAS LATE
WEDNESDAY...BEFORE THE LIGHT PCPN SPREADS NORTH.
ALL MODELS ARE RELATIVELY SIMILAR IN THE POSITIONING OF THE SFC
LOW AND MOISTURE COMING IN OFF THE BRINK DURING THE MID TO LATE
PORTION OF THE WORK WEEK. AHEAD OF THIS PCPN...LOW CLOUDS WILL
MOVE IN OFF THE GULF OF MAINE. THIS MOISTURE WILL END OUR PERIOD
OF OUR LARGE DIURNAL RANGES FROM THE DAYTIME MAXES TO THE
OVERNIGHT LOWS.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
SHORT TERM...LOW CHANCE THAT SOME COASTAL STRATUS ARRIVES ACROSS
SRN NH AND SWRN ME NEAR DAYBREAK THIS MORNING. OTHERWISE VFR CONDS
TO PREVAIL UNTIL AFTER 00Z TUE. IFR CONDS ARE EXPECTED FOR COASTAL
TERMINALS AS CIGS AND POSSIBLY VSBYS DECREASE IN STRATUS.
LONG TERM...
MARINE FOG LOOKS LIKELY TUESDAY AND WEDNESDAY MORNINGS RESULTING
IN SOME AREAS OF MVFR OR LOWER. SCATTERED SHOWERS ENTER THE REGION
FROM SOUTH TO NORTH WEDNESDAY NIGHT THROUGH THE END OF THE WORK
WEEK.
&&
.MARINE...
SHORT TERM...LONG PERIOD SWELL AROUND 5 FT WILL CONTINUE EARLY
THIS MORNING. GIVEN LACK OF STEEPNESS TO THE SEAS...NO SCA IS
EXPECTED. WINDS WILL REMAIN BLO 25 KT.
LONG TERM...
MARINE FOG IS LIKELY TUESDAY AND WEDNESDAY MORNINGS
WITH POOR VISIBILITY. WINDS WILL REMAIN BELOW SMALL CRAFT CRITERIA.
SEAS MAY BRIEFLY REACH 5 FT THURSDAY.
&&
.FIRE WEATHER...
HIGH PRESSURE WILL REMAIN IN CONTROL OF THE WEATHER WITH NO RAIN
EXPECTED THROUGH TUESDAY. DAYTIME RELATIVE HUMIDITY WILL APPROACH
25% AWAY FROM THE COAST BUT WINDS ARE EXPECTED TO REMAIN
RELATIVELY LIGHT THROUGH THE PERIOD. A CHANCE FOR WETTING RAINS
WILL ARRIVE LATER WEDNESDAY ACROSS THE SOUTH...AND BY THURSDAY
FOR NORTHERN ZONES.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS ANZ152-154 TIL 2 AM
TUESDAY.
&&
$$
LEGRO/JC/MLE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
437 PM EDT MON MAY 6 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 405 PM EDT MON MAY 6 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW BLOCKY FLOW ACROSS THE
CONUS TO THE S OF NEARLY ZONAL FLOW ACROSS CNTRL CANADA. A NARROW
RIDGE EXTENDS FROM SRN BRITISH COLUMBIA E ACROSS THE UPPER GREAT
LAKES TO NEW ENGLAND. FARTHER S...CLOSED MID LEVEL LOWS WERE LOCATED
JUST OFF THE CA COAST...OVER SD AND OVER THE SE CONUS. WITH THE
UPPER GREAT LAKES UNDER THE RIDGE...IT`S BEEN A PLEASANT EARLY MAY
DAY ACROSS UPPER MI AS DEEP DRY COLUMN IS ALLOWING FOR ABUNDANT
SUNSHINE. LAKE BREEZES HAVE DEVELOPED ACROSS THE BOARD. WHILE IT`S
CHILLY ALONG LAKE SUPERIOR WITH TEMPS IN THE 40S...SIGNIFICANT
COOLING HAS YET TO OCCUR ALONG MOST OF THE LAKE MI SHORELINE.
INLAND...TEMPS HAVE SOARED THRU THE 60S TO AS HIGH AS THE LOW/MID
70S. LAST BIT OF LINGERING FOG OVER WRN LAKE SUPERIOR BTWN THE
APOSTLE ISLANDS AND UPPER MI HAS JUST ABOUT DISSIPATED AS OF 1930Z.
WITH LITTLE CHANGE IN THE AIR MASS THRU TUE...FCST FOR TONIGHT/TUE
WILL BE SIMILAR TO LAST NIGHT/TODAY. LIGHT/CALM WIND AND CLEAR SKIES
WILL LEAD TO GOOD RADIATIONAL COOLING CONDITIONS TONIGHT. HOWEVER...
PRECIPITABLE WATER DOES RISE SOME COMPARED TO LAST NIGHT OVER THE W
HALF OR SO (UP TOWARD NORMAL FROM 60PCT OF NORMAL LAST NIGHT). ALONG
WITH AIR MASS MODERATION TODAY...MINS TONIGHT SHOULD BE SEVERAL
DEGREES HIGHER THAN LAST NIGHT. COLUMN REMAINS DRIER OVER THE E...SO
MINS THERE WILL PROBABLY BE WITHIN A COUPLE OF DEGREES OF LAST
NIGHTS MINS. OVERALL...EXPECT MIN TEMPS TONIGHT IN THE 30S. MIGHT
SEE SOME PATCHY GROUND FOG OVER THE INTERIOR W LATE TONIGHT. 850MB
TEMPS TUE ARE NEARLY THE SAME AS TODAY. WITH ABUNDANT SUNSHINE AGAIN
(SHOULD BE SOME CU OVER THE W)...MAX TEMPS WILL BE SIMILAR TO WHAT
IS BEING OBSERVED THIS AFTN. SFC HIGH PRES RIDGED ACROSS THE UPPER
LAKES WILL LEAD TO ANOTHER DAY OF LAKE BREEZES. HOWEVER...WITH HIGH
CENTER SETTING UP A LITTLE FARTHER E...LIGHT SOUTHERLY GRADIENT FLOW
SHOULD LEAD TO A LESS AGGRESSIVE INLAND PUSH OF THE LAKE SUPERIOR
LAKE BREEZE...AND COOLING SHOULD BE A LITTLE STRONGER ALONG LAKE MI
SAT AFTN COMPARED TO TODAY. TAKING INTO ACCOUNT MIXING DEPTH...
DWPTS SHOULD TANK IN SOME INLAND AREAS WITH RH BOTTOMING OUT AS LOW
AS AROUND 20PCT. IN GENERAL...RH SHOULD BE IN 20S INLAND.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 436 PM EDT MON MAY 6 2013
THE 500MB RIDGE THAT HAS BEEN SET UP ACROSS UPPER MICHIGAN WILL BE
EXITING EASTWARD TUESDAY NIGHT...WITH AN OPEN WAVE/TROUGH EXTENDING
FROM NORTHERN CANADA THROUGH THE DAKOTAS SHIFTING TOWARD MINNESOTA
AND ONTARIO.
WEAK SSW WINDS FLOW WILL SLOWLY BRING BACK INCREASED MOISTURE
THROUGH THE DAY WEDNESDAY...WITH PW VALUES JUMPING AT OR ABOVE 1IN
BY MID AFTERNOON OVER THE WESTERN THIRD OF THE CWA /175 PERCENT OR
NORMAL OR MORE/. THE MAIN RESULT WILL BE INCREASED CLOUD COVER. A
WEAKENING SFC TROUGH WILL SINK FROM NW LAKE SUPERIOR AT DAYBREAK
WEDNESDAY. FCST MODELS ARE VERY CONSISTENT WITH THE TRACK/TIMING OF
THE TROUGH AS OF THE 12Z RUNS. EXPECT THE TROUGH TO PUSH ACROSS
CENTRAL LAKE SUPERIOR BY 18Z...AND THEN SINK ACROSS UPPER MI
WEDNESDAY AFTERNOON...TO JUST S OF THE CWA BY 06Z THURSDAY. A FEW
SHOWERS WILL BE POSSIBLE WEDNESDAY NIGHT THROUGH THURSDAY...WITH
TOTAL QPF AROUND A TENTH OF AN INCH OR LESS.
STRONG HIGH PRESSURE ACROSS MOST OF CENTRAL CANADA WILL SLOWLY SINK
IN BEHIND THE TROUGH...BRINGING WITH IT A RETURN OF DRIER AND COLDER
AIR. 850MB TEMPS ARE ANTICIPATED TO FALL FROM AROUND 9C WEDNESDAY
AFTERNOON TO AROUND 4C BY FRIDAY AFTERNOON.
LOOKING MORE AT THE FIRE FRONT...THE CENTRAL AND EASTERN UPPER
MICHIGAN WILL CONTINUE TO BE THE DRIEST THROUGH AT LEAST FRIDAY
NIGHT.
WINDS MAY BECOME A CONCERN ON SATURDAY...PICKING UP OUT OF A NW
DIRECTION THROUGHOUT THE DAY...BEHIND A STRONGER COLD FRONT WITH A
REINFORCING SHORTWAVE. A 30-35KT LLJ CORE AROUND 800BM THROUGH
MUCH OF THE DAY SATURDAY OVER THE WEST...RESULTING IN 20-25KT GUSTS
SATURDAY THROUGH MUCH OF SUNDAY.
ON A POSITIVE NOTE...A TENTH TO QUARTER OF AN INCH IS OF RAIN IS
FORECAST...AND MUCH COLDER AIR WILL BE SINKING IN. 850MB TEMPS WILL
COOL SIGNIFICANTLY...WITH THE 12Z ECMWF COMING IN WITH -8 TO -10C
READINGS FROM 06-18Z SUNDAY. WITH A DEEPER AND SLOWER SYSTEM
OVERALL...A FEW FLURRIES WILL BE POSSIBLE FROM SATURDAY THROUGH
SUNDAY. THE GOOD NEWS FOR THOSE WHO WOULD RATHER NOT SEE ANOTHER
SNOWFLAKE UNTIL THE FALL...MOST OF THE MOISTURE WILL BE OUT OF THE
AREA BEFORE THE COLD AIR ARRIVES. DO NOT EXPECT ANY TRAVEL CONCERNS
OR PLOWING NEEDED...GIVEN THE STRENGTH OF THE SUN THIS TIME OF
YEAR...AND THE WARM ROADWAYS. GRASSY SURFACES WILL REALLY SEE THE
ONLY CHANCE OF ANY DUSTING OF SNOW.
AFTER A COOL WEEKEND WITH HIGHS IN THE 40S TO AROUND 50...TEMPS WILL
WARM UP AGAIN TO NEAR NORMAL READINGS BY MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 135 PM EDT MON MAY 6 2013
EXPECT VFR CONDITIONS/LIGHT WINDS AT KIWD/KCMX/KSAW THIS TAF PERIOD
WITH DRY HIGH PRES DOMINATING. HOWEVER...THERE MAY BE ONE EXCEPTION.
SOME FOG (MVFR VIS) MAY DEVELOP AT KIWD LATE TONIGHT. NOT OUT OF THE
QUESTION THAT BRIEF IFR OR EVEN LIFR COULD OCCUR AS WELL.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 405 PM EDT MON MAY 6 2013
QUIET WEATHER WILL CONTINUE OVER THE UPPER GREAT LAKES FOR THE NEXT
COUPLE OF DAYS. WITH HIGH PRES RIDGE REMAINING OVER THE AREA...WINDS
WILL LIKELY REMAIN UNDER 15KT THRU WED AFTN. THEN...A COLD FRONT
DROPPING SOUTHEAST ACROSS THE UPPER GREAT LAKES WEDNESDAY NIGHT WILL
BRING A WIND SHIFT AND STRONGER WINDS INTO THE 15-25KT RANGE FOR A
TIME LATER WED NIGHT INTO THU. WINDS WILL DIMINISH HEADING INTO FRI
AS A HIGH PRES SYSTEM MOVES ACROSS NRN ONTARIO. A STRONG COLD FRONT
PASSING FRI NIGHT/SAT MORNING WILL BRING ANOTHER ROUND OF 15-25KT
WINDS FOR SAT.
&&
.HYDROLOGY...
ISSUED AT 436 PM EDT MON MAY 6 2013
HYDROLOGY CONCERNS CONTINUE...BUT ARE SLOWLY DIMINISHING AT ALL
SITES EXCEPT FOR LAKE LINDEN ON THE TRAP ROCK RIVER WHICH HAS BEEN
SHOWING ITS USUAL DIURNAL INCREASE AS A RESULT OF THE SIGNIFICANT
SNOW PACK STILL MELTING ACROSS THE KEWEENAW PENINSULA. THE LATEST
SNOW DEPTH OBSERVATIONS /FROM EARLIER THIS MORNING AROUND 8AM/ STILL
HAVE AROUND 3IN AT IRONWOOD...AND 7IN AT ATLANTIC MINE. A FEW
POCKETS OF HIGHER AMOUNTS ARE LIKELY ACROSS THE KEWEENAW.
THE ONGOING FLOODING ON THE STURGEON RIVER AT ALSTON AND
CHASSELL...THE MICHIGAMME RIVER AROUND WITCH LAKE...AND THE PAINT
RIVER NEAR CRYSTAL FALLS WILL REMAIN A CONCERN FOR THE NEXT COUPLE
OF DAYS. FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD WARNINGS
AND ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...ROLFSON
MARINE...ROLFSON
HYDROLOGY...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
406 PM EDT MON MAY 6 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 405 PM EDT MON MAY 6 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW BLOCKY FLOW ACROSS THE
CONUS TO THE S OF NEARLY ZONAL FLOW ACROSS CNTRL CANADA. A NARROW
RIDGE EXTENDS FROM SRN BRITISH COLUMBIA E ACROSS THE UPPER GREAT
LAKES TO NEW ENGLAND. FARTHER S...CLOSED MID LEVEL LOWS WERE LOCATED
JUST OFF THE CA COAST...OVER SD AND OVER THE SE CONUS. WITH THE
UPPER GREAT LAKES UNDER THE RIDGE...IT`S BEEN A PLEASANT EARLY MAY
DAY ACROSS UPPER MI AS DEEP DRY COLUMN IS ALLOWING FOR ABUNDANT
SUNSHINE. LAKE BREEZES HAVE DEVELOPED ACROSS THE BOARD. WHILE IT`S
CHILLY ALONG LAKE SUPERIOR WITH TEMPS IN THE 40S...SIGNIFICANT
COOLING HAS YET TO OCCUR ALONG MOST OF THE LAKE MI SHORELINE.
INLAND...TEMPS HAVE SOARED THRU THE 60S TO AS HIGH AS THE LOW/MID
70S. LAST BIT OF LINGERING FOG OVER WRN LAKE SUPERIOR BTWN THE
APOSTLE ISLANDS AND UPPER MI HAS JUST ABOUT DISSIPATED AS OF 1930Z.
WITH LITTLE CHANGE IN THE AIR MASS THRU TUE...FCST FOR TONIGHT/TUE
WILL BE SIMILAR TO LAST NIGHT/TODAY. LIGHT/CALM WIND AND CLEAR SKIES
WILL LEAD TO GOOD RADIATIONAL COOLING CONDITIONS TONIGHT. HOWEVER...
PRECIPITABLE WATER DOES RISE SOME COMPARED TO LAST NIGHT OVER THE W
HALF OR SO (UP TOWARD NORMAL FROM 60PCT OF NORMAL LAST NIGHT). ALONG
WITH AIR MASS MODERATION TODAY...MINS TONIGHT SHOULD BE SEVERAL
DEGREES HIGHER THAN LAST NIGHT. COLUMN REMAINS DRIER OVER THE E...SO
MINS THERE WILL PROBABLY BE WITHIN A COUPLE OF DEGREES OF LAST
NIGHTS MINS. OVERALL...EXPECT MIN TEMPS TONIGHT IN THE 30S. MIGHT
SEE SOME PATCHY GROUND FOG OVER THE INTERIOR W LATE TONIGHT. 850MB
TEMPS TUE ARE NEARLY THE SAME AS TODAY. WITH ABUNDANT SUNSHINE AGAIN
(SHOULD BE SOME CU OVER THE W)...MAX TEMPS WILL BE SIMILAR TO WHAT
IS BEING OBSERVED THIS AFTN. SFC HIGH PRES RIDGED ACROSS THE UPPER
LAKES WILL LEAD TO ANOTHER DAY OF LAKE BREEZES. HOWEVER...WITH HIGH
CENTER SETTING UP A LITTLE FARTHER E...LIGHT SOUTHERLY GRADIENT FLOW
SHOULD LEAD TO A LESS AGGRESSIVE INLAND PUSH OF THE LAKE SUPERIOR
LAKE BREEZE...AND COOLING SHOULD BE A LITTLE STRONGER ALONG LAKE MI
SAT AFTN COMPARED TO TODAY. TAKING INTO ACCOUNT MIXING DEPTH...
DWPTS SHOULD TANK IN SOME INLAND AREAS WITH RH BOTTOMING OUT AS LOW
AS AROUND 20PCT. IN GENERAL...RH SHOULD BE IN 20S INLAND.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 355 AM EDT MON MAY 6 2013
THE QUIET WEATHER WILL CONTINUE FOR THE START OF THE LONG TERM
PERIOD...AS DUAL CUTOFF LOWS /ONE OVER THE SE CONUS AND THE OTHER
NEAR CALIFORNIA/ KEEP THE UNSETTLED WEATHER OVER THE SOUTHERN HALF
OF THE CONUS. MEANWHILE...THE NORTHERN STREAM JET RUNNING WEST-EAST
ACROSS CENTRAL CANADA WILL KEEP THE COLDER AIR LOCKED UP TO THE
NORTH FOR THE TIME BEING.
AT THE SURFACE...HIGH PRESSURE WILL STILL BE OVER THE UPPER GREAT
LAKES FOR TUESDAY INTO WEDNESDAY MORNING AND PRODUCE MOSTLY CLEAR
SKIES ACROSS THE AREA. THERE ARE STILL HINTS OF SOME HIGH-BASED
DIURNAL CU OVER THE WESTERN CWA ON TUESDAY AFTERNOON...BUT NOT
EXPECTING MUCH MORE THAN THAT. WITH THE DEEP MIXING...EXPECT
ANOTHER ABOVE NORMAL DAY OVER THE CWA...WITH HIGHS IN THE 70S
EXCEPT WHERE LAKE BREEZES KEEP TEMPERATURES COOLER NEAR THE GREAT
LAKES. TEMPERATURES SHOULD BE SIMILAR ON WEDNESDAY...ALTHOUGH THE
INCREASING CLOUDS AND POTENTIAL PRECIPITATION MAY KEEP THE WEST
HALF A LITTLE COOLER. DID TREND DEWPOINTS DOWN FOR TUESDAY AFTERNOON
OVER THE CENTRAL AND EAST BASED OFF THE LAST COUPLE OF DAYS. WITH
THE GOOD MIXING THOSE DAYS...RH VALUES FELL INTO THE UPPER TEENS AND
20S AWAY FROM THE LAKE INFLUENCES AND WOULD EXPECT THE SAME FOR
TUESDAY. THAT IDEA MATCHES MIXED LAYER DEWPOINTS FROM THE MODELS AND
TRENDED THAT DIRECTION.
THE FIRST CHANCE OF PRECIPITATION FOR THE LONG TERM PERIOD WILL
COME LATE WEDNESDAY AFTERNOON AND INTO WEDNESDAY NIGHT. THIS IS DUE
TO A SHORTWAVE IN THE NORTHERN STREAM WAVE PRODUCING A LOW THAT
SHIFTS EAST INTO QUEBEC ON WEDNESDAY. A TRAILING COLD FRONT WILL
THEN TRY TO DIVE SOUTHEAST ACROSS THE UPPER GREAT LAKES ON
WEDNESDAY NIGHT INTO THURSDAY MORNING. THE MAIN FORECAST IMPACT IS
WHAT WILL HAPPEN WITH THE MOISTURE AND SMALL CLOSED PIECE OF ENERGY
THAT TRIES TO DRIFT NORTHEAST AND INTERACT WITH THE NORTHERN
STREAM. THE MODELS CONTINUE TO DIFFER WITH THIS INTERACTION AND
PROVIDES UNCERTAINTY IN THE QPF AMOUNTS. WILL CONTINUE TO GO WITH A
GENERAL CONSENSUS POP/QPF DURING THIS PERIOD AND HAVE SLIGHTS
OR LOW CHANCE POPS FOR LATE WEDNESDAY AFTERNOON INTO THURSDAY
MORNING.
WITH THE COLD FRONT MOVING SOUTHEAST OF THE AREA...EXPECT DRIER AIR
TO DIMINISHING PRECIPITATION CHANCES BY THURSDAY AFTERNOON AS A
CANADIAN HIGH PRESSURE RIDGE DROPS OVER THE AREA. THIS RIDGE WILL
REMAIN OVER THE AREA FOR FRIDAY AND LEAD TO DRY BUT COOLER WEATHER
WITH HIGHS IN THE 50S.
A MUCH STRONGER NORTHERN STREAM WAVE WILL BE DIVING SOUTHEAST
TOWARDS THE UPPER GREAT LAKES ON SATURDAY AND BRING MUCH COOLER
WEATHER FOR THE WEEKEND. WILL CONTINUE THE CHANCE POPS WITH THIS
SYSTEM...BUT WITH LITTLE MOISTURE RETURN AHEAD OF THE WAVE...QPF
AMOUNTS WILL BE ON THE LIGHT SIDE. PRECIPITATION SHOULD FALL AS
RAIN...AS THE COLDEST AIR DOESN/T ARRIVE UNTIL AFTER MOST OF THE
DEEP MOISTURE EXITS. WITH THE BETTER CONSISTENCY IN THE MODELS FOR
THIS WAVE...HAVE TRENDED HIGHS DOWN INTO THE UPPER 40S OR LOWER 50S
FOR SATURDAY ALTHOUGH THERE IS SOME CONCERNS THE EAST COULD SEE
WARMER HIGHS AROUND DAYBREAK AND THEN FALLING THROUGH THE DAY. THE
TROUGH WILL QUICKLY SHIFT EAST TO THE NEW ENGLAND STATES ON SUNDAY
AND ALLOW RETURN FLOW TO DEVELOP. SUNDAY SHOULD BE DRY BUT COOL BUT
THEN WARMING IS EXPECTED FOR THE FIRST PART OF NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 135 PM EDT MON MAY 6 2013
EXPECT VFR CONDITIONS/LIGHT WINDS AT KIWD/KCMX/KSAW THIS TAF PERIOD
WITH DRY HIGH PRES DOMINATING. HOWEVER...THERE MAY BE ONE EXCEPTION.
SOME FOG (MVFR VIS) MAY DEVELOP AT KIWD LATE TONIGHT. NOT OUT OF THE
QUESTION THAT BRIEF IFR OR EVEN LIFR COULD OCCUR AS WELL.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 405 PM EDT MON MAY 6 2013
QUIET WEATHER WILL CONTINUE OVER THE UPPER GREAT LAKES FOR THE NEXT
COUPLE OF DAYS. WITH HIGH PRES RIDGE REMAINING OVER THE AREA...WINDS
WILL LIKELY REMAIN UNDER 15KT THRU WED AFTN. THEN...A COLD FRONT
DROPPING SOUTHEAST ACROSS THE UPPER GREAT LAKES WEDNESDAY NIGHT WILL
BRING A WIND SHIFT AND STRONGER WINDS INTO THE 15-25KT RANGE FOR A
TIME LATER WED NIGHT INTO THU. WINDS WILL DIMINISH HEADING INTO FRI
AS A HIGH PRES SYSTEM MOVES ACROSS NRN ONTARIO. A STRONG COLD FRONT
PASSING FRI NIGHT/SAT MORNING WILL BRING ANOTHER ROUND OF 15-25KT
WINDS FOR SAT.
&&
.HYDROLOGY...
ISSUED AT 355 AM EDT MON MAY 6 2013
HYDROLOGY CONCERNS WILL REMAIN OVER THE COMING DAYS...UNTIL THE
REMAINING SNOW PACK MELTS OVER THE NORTHWESTERN THIRD OF UPPER
MICHIGAN. VISIBLE SATELLITE AND MODIS IMAGERY YESTERDAY STILL SHOWS
SNOW REMAINING IN THE HIGHER TERRAIN LOCATIONS OF THE HURON
MOUNTAINS AND THE KEWEENAW PENINSULA. DID SEE RISES AT SOME OF THE
SITES OVER THE WEST /ESPECIALLY TRRM4/ WITH THE WARMER TEMPERATURES
YESTERDAY AND WOULD EXPECT THAT TO CONTINUE UNTIL THE REMAINING
SNOW IS GONE. AT THIS TIME...WOULD THINK TRRM4 WILL BE THE MAIN
THREAT FOR REACHING ADVISORY OR FLOOD STAGE FROM THIS ADDITIONAL
MELT.
OTHERWISE...THE ONGOING FLOODING ON THE STURGEON RIVER AT ALSTON AND
CHASSELL...THE MICHIGAMME RIVER AROUND WITCH LAKE...AND THE PAINT
RIVER NEAR CRYSTAL FALLS WILL REMAIN A CONCERN FOR THE NEXT COUPLE
OF DAYS. THE REST RIVER LEVELS ARE ON THE DOWNWARD TREND AND
WILL LIKELY CONTINUE THIS WEEK.
FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD WARNINGS AND
ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...ROLFSON
HYDROLOGY...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
136 PM EDT MON MAY 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM EDT MON MAY 6 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG STRETCHING
FM THE NE CONUS W INTO THE UPR GRT LKS TO THE N OF CUTOFF LO OVER
THE SE CONUS. VERY DRY AIRMASS SHOWN ON THE 00Z GRB/APX RAOBS...
WHICH SHOW A PWAT ARND 0.25 INCH OR 50 PCT OF NORMAL...DOMINATES THE
CWA. SO SKIES ARE MOCLR EXCEPT FOR SOME HI CLDS. SFC HI PRES IS
CENTERED NEAR WRN LK SUP...AND SOME LO CLDS/FOG ARE APRNT OVER WRN
LK SUP NEAR THE W COAST OF UPR MI CLOSER TO MOISTER AIRMASS SHOWN ON
THE 00Z INL RAOB. DESPITE THE LGT WINDS AND TEMPS FALLING TOWARD 30
CLOSER TO THIS MSTR...NO FOG HAS YET FORMED OVER WRN UPR MI AS OF
FCST ISSUANCE.
TODAY/TNGT...UPR RDG IS FCST TO REMAIN DOMINANT THRU THIS TIME WITH
SFC HI PRES REMAINING NEARLY STNRY OVER LK SUP. WITH DRY AIRMASS
ALSO LINGERING...THE ONLY MAJOR CONCERNS ARE TEMPS...THE POTENTIAL
FOR FOG THIS MRNG/TNGT...AND POTENTIAL LOW RH THIS AFTN...ESPECIALLY
OVER THE E HALF CLOSER TO CORE OF DRY AIRMASS. BEST CHC FOR FOG
EARLY THIS MRNG WL BE OVER THE INTERIOR W...CLOSER TO AREA OF FOG/
LO CLD STRETCHING FM THE W SHORE OF THE KEWEENAW DOWN TOWARD
IWD/ASX. ANY FOG THAT DOES DVLP SHOULD BURN OFF FAIRLY QUICKLY WITH
THE ONSET OF DAYTIME HEATING.
WITH H85 TEMPS TOPPING OUT AT 9-10C AGAIN TODAY...EXPECT MAX TEMPS
TO BE SIMILAR TO WHAT OCCURRED YDAY AT MOST LOCATIONS. THE ONLY
EXCEPTION WL BE OVER THE NCENTRAL AND W NEAR LK SUP...WHERE A WEAKER
SYNOPTIC FLOW THAN YDAY WL LIMIT THE INLAND EXTENT OF LK MODERATION.
SO ALTHOUGH TEMPS NEAR THE SHORE IN THIS AREA MIGHT HAVE A HARD TIME
TOPPING 50...MUCH OF THE NCENTRAL AND W WL BE WARMER THAN YDAY.
MIXING TO H8-85 ON NAM/GFS FCST SDNGS YIELDS HI TEMPS UP TO 70-75
OVER THE INTERIOR AWAY FM LOCAL LK BREEZE MODERATION. PREFER THE
DRIER LOOK TO THE NAM FCST SDNGS GIVEN BONE DRY GRB/APX RAOBS. DEEP
MIXING ON THESE FCST SDNGS SUG DEWPTS WL MIX OUT AS LO AS 30 TO 35
OVER THE INTERIOR DURING PEAK HEATING...LOWERING MIN RH AS LO AS
20-25 PCT. THE BEST CHC FOR THE LOWER DEWPTS WL BE OVER THE E WHERE
THE GROUND IS QUITE A BIT DRIER THAN OVER THE W/CENTRAL. FORTUNATELY
WINDS WL BE LGT...SO NO FIRE WX HEADLINES ARE NECESSARY.
FOR TNGT...WITH LGT WINDS AND DRY AIRMASS LINGERING...EXPECT A
HEALTHY DROP OF TEMP. PREFER TO TEND TOWARD THE LOWER END OF
GUIDANCE FOR MIN TEMPS...BUT MODERATING AIRMASS SUGGESTS TEMPS TNGT
WL NOT BE AS CHILLY AS EARLY THIS MRNG. SINCE FOG HAS BEEN SLOW TO
FORM THIS MRNG AND THE LLVLS TNGT WL LIKELY TO BE AS DRY...OPTED TO
MAINTAIN FCST FOR PATCHY FOG ONLY OVER THE INTERIOR W WHERE TEMPS AT
SOME OF THE FAVORED COOL SPOTS SEE MIN TEMPS FALLING TOWARD 33.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 355 AM EDT MON MAY 6 2013
THE QUIET WEATHER WILL CONTINUE FOR THE START OF THE LONG TERM
PERIOD...AS DUAL CUTOFF LOWS /ONE OVER THE SE CONUS AND THE OTHER
NEAR CALIFORNIA/ KEEP THE UNSETTLED WEATHER OVER THE SOUTHERN HALF
OF THE CONUS. MEANWHILE...THE NORTHERN STREAM JET RUNNING WEST-EAST
ACROSS CENTRAL CANADA WILL KEEP THE COLDER AIR LOCKED UP TO THE
NORTH FOR THE TIME BEING.
AT THE SURFACE...HIGH PRESSURE WILL STILL BE OVER THE UPPER GREAT
LAKES FOR TUESDAY INTO WEDNESDAY MORNING AND PRODUCE MOSTLY CLEAR
SKIES ACROSS THE AREA. THERE ARE STILL HINTS OF SOME HIGH-BASED
DIURNAL CU OVER THE WESTERN CWA ON TUESDAY AFTERNOON...BUT NOT
EXPECTING MUCH MORE THAN THAT. WITH THE DEEP MIXING...EXPECT
ANOTHER ABOVE NORMAL DAY OVER THE CWA...WITH HIGHS IN THE 70S
EXCEPT WHERE LAKE BREEZES KEEP TEMPERATURES COOLER NEAR THE GREAT
LAKES. TEMPERATURES SHOULD BE SIMILAR ON WEDNESDAY...ALTHOUGH THE
INCREASING CLOUDS AND POTENTIAL PRECIPITATION MAY KEEP THE WEST
HALF A LITTLE COOLER. DID TREND DEWPOINTS DOWN FOR TUESDAY AFTERNOON
OVER THE CENTRAL AND EAST BASED OFF THE LAST COUPLE OF DAYS. WITH
THE GOOD MIXING THOSE DAYS...RH VALUES FELL INTO THE UPPER TEENS AND
20S AWAY FROM THE LAKE INFLUENCES AND WOULD EXPECT THE SAME FOR
TUESDAY. THAT IDEA MATCHES MIXED LAYER DEWPOINTS FROM THE MODELS AND
TRENDED THAT DIRECTION.
THE FIRST CHANCE OF PRECIPITATION FOR THE LONG TERM PERIOD WILL
COME LATE WEDNESDAY AFTERNOON AND INTO WEDNESDAY NIGHT. THIS IS DUE
TO A SHORTWAVE IN THE NORTHERN STREAM WAVE PRODUCING A LOW THAT
SHIFTS EAST INTO QUEBEC ON WEDNESDAY. A TRAILING COLD FRONT WILL
THEN TRY TO DIVE SOUTHEAST ACROSS THE UPPER GREAT LAKES ON
WEDNESDAY NIGHT INTO THURSDAY MORNING. THE MAIN FORECAST IMPACT IS
WHAT WILL HAPPEN WITH THE MOISTURE AND SMALL CLOSED PIECE OF ENERGY
THAT TRIES TO DRIFT NORTHEAST AND INTERACT WITH THE NORTHERN
STREAM. THE MODELS CONTINUE TO DIFFER WITH THIS INTERACTION AND
PROVIDES UNCERTAINTY IN THE QPF AMOUNTS. WILL CONTINUE TO GO WITH A
GENERAL CONSENSUS POP/QPF DURING THIS PERIOD AND HAVE SLIGHTS
OR LOW CHANCE POPS FOR LATE WEDNESDAY AFTERNOON INTO THURSDAY
MORNING.
WITH THE COLD FRONT MOVING SOUTHEAST OF THE AREA...EXPECT DRIER AIR
TO DIMINISHING PRECIPITATION CHANCES BY THURSDAY AFTERNOON AS A
CANADIAN HIGH PRESSURE RIDGE DROPS OVER THE AREA. THIS RIDGE WILL
REMAIN OVER THE AREA FOR FRIDAY AND LEAD TO DRY BUT COOLER WEATHER
WITH HIGHS IN THE 50S.
A MUCH STRONGER NORTHERN STREAM WAVE WILL BE DIVING SOUTHEAST
TOWARDS THE UPPER GREAT LAKES ON SATURDAY AND BRING MUCH COOLER
WEATHER FOR THE WEEKEND. WILL CONTINUE THE CHANCE POPS WITH THIS
SYSTEM...BUT WITH LITTLE MOISTURE RETURN AHEAD OF THE WAVE...QPF
AMOUNTS WILL BE ON THE LIGHT SIDE. PRECIPITATION SHOULD FALL AS
RAIN...AS THE COLDEST AIR DOESN/T ARRIVE UNTIL AFTER MOST OF THE
DEEP MOISTURE EXITS. WITH THE BETTER CONSISTENCY IN THE MODELS FOR
THIS WAVE...HAVE TRENDED HIGHS DOWN INTO THE UPPER 40S OR LOWER 50S
FOR SATURDAY ALTHOUGH THERE IS SOME CONCERNS THE EAST COULD SEE
WARMER HIGHS AROUND DAYBREAK AND THEN FALLING THROUGH THE DAY. THE
TROUGH WILL QUICKLY SHIFT EAST TO THE NEW ENGLAND STATES ON SUNDAY
AND ALLOW RETURN FLOW TO DEVELOP. SUNDAY SHOULD BE DRY BUT COOL BUT
THEN WARMING IS EXPECTED FOR THE FIRST PART OF NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 135 PM EDT MON MAY 6 2013
EXPECT VFR CONDITIONS/LIGHT WINDS AT KIWD/KCMX/KSAW THIS TAF PERIOD
WITH DRY HIGH PRES DOMINATING. HOWEVER...THERE MAY BE ONE EXCEPTION.
SOME FOG (MVFR VIS) MAY DEVELOP AT KIWD LATE TONIGHT. NOT OUT OF THE
QUESTION THAT BRIEF IFR OR EVEN LIFR COULD OCCUR AS WELL.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 355 AM EDT MON MAY 6 2013
A QUIET PERIOD OF WEATHER IS EXPECTED THROUGH THE PERIOD...WITH THE
WINDS LIKELY STAYING BELOW 25KTS. HIGH PRESSURE THAT HAS SETUP OVER
THE AREA WILL REMAIN THROUGH WEDNESDAY MORNING AND LEAD TO LIGHT
WINDS. THEN...A COLD FRONT DROPPING SOUTHEAST ACROSS THE UPPER GREAT
LAKES ON WEDNESDAY NIGHT WILL BRING A WIND SHIFT BUT ONLY 10-20KT
WINDS. WEAK HIGH PRESSURE WILL MOVE OVER NORTHERN LAKE SUPERIOR FOR
THURSDAY AFTERNOON INTO FRIDAY AND DIMINISH THE WINDS.
&&
.HYDROLOGY...
ISSUED AT 355 AM EDT MON MAY 6 2013
HYDROLOGY CONCERNS WILL REMAIN OVER THE COMING DAYS...UNTIL THE
REMAINING SNOW PACK MELTS OVER THE NORTHWESTERN THIRD OF UPPER
MICHIGAN. VISIBLE SATELLITE AND MODIS IMAGERY YESTERDAY STILL SHOWS
SNOW REMAINING IN THE HIGHER TERRAIN LOCATIONS OF THE HURON
MOUNTAINS AND THE KEWEENAW PENINSULA. DID SEE RISES AT SOME OF THE
SITES OVER THE WEST /ESPECIALLY TRRM4/ WITH THE WARMER TEMPERATURES
YESTERDAY AND WOULD EXPECT THAT TO CONTINUE UNTIL THE REMAINING
SNOW IS GONE. AT THIS TIME...WOULD THINK TRRM4 WILL BE THE MAIN
THREAT FOR REACHING ADVISORY OR FLOOD STAGE FROM THIS ADDITIONAL
MELT.
OTHERWISE...THE ONGOING FLOODING ON THE STURGEON RIVER AT ALSTON AND
CHASSELL...THE MICHIGAMME RIVER AROUND WITCH LAKE...AND THE PAINT
RIVER NEAR CRYSTAL FALLS WILL REMAIN A CONCERN FOR THE NEXT COUPLE
OF DAYS. THE REST RIVER LEVELS ARE ON THE DOWNWARD TREND AND
WILL LIKELY CONTINUE THIS WEEK.
FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD WARNINGS AND
ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...SRF
HYDROLOGY...SRF
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
256 PM MDT Mon May 6 2013
.DISCUSSION...
Tonight through Wednesday...Fairly benign weather pattern will
continue overnight. An upper ridge remains in place across central
and northern Montana with associated subsidence providing cloud-
free skies and mild temperatures. Circulation from an upper low
offshore of the California coast is spreading moisture and
instability across the inter-mountain region and into extreme
southern and southwest Montana. Models indicate some CAPE is
available over the area but HRRR analysis indicates moisture is
lacking and very few thunderstorms are depicted through the early
evening hours. The upper low begins moving east on Tuesday with
showers and/or thunderstorms becoming a bit more numerous across
the south and southwest during the afternoon. By Wednesday, the
upper ridge gets suppressed to the south and northwest flow aloft
sets up over the area. Enough moisture and instability will be
present for isolated thunderstorms across the area. Temperatures
will remain above seasonal averages. Emanuel
Wednesday Night through Monday...Medium range models continue to
indicate that unsettled weather will remain across the area through
Saturday. An upper level ridge of high pressure from along the
California coast into the Pacific Northwest and an upper level
trough of low pressure over central/eastern Canada will combine to
keep Montana under a moist and cyclonic northwesterly flow aloft.
Weak disturbances in the flow will generally keep a chance of mainly
afternoon and evening showers and thunderstorms over the area.
Moisture being drawn north by an upper level low pressure area
moving across the central Rockies Wednesday night through Thursday
night will enhance this chance of measurable precipitation. However,
the models seem to agree with this forecast cycle that a strong
Canadian cold front will move south through the area on Friday. Have
therefore increased the overall chance for showers/thunderstorms
during this time and introduced breezy northerly winds in the wake
of the front. For Saturday night into Sunday night, models are in
better agreement with moving the upper level ridge will move east
into Montana. Have mostly gone with dry conditions during this time,
with only a slight chance of showers/thunderstorms in the mountains.
As the ridge axis moves east of the area, models are indicating that
a moist southwesterly flow aloft will combine with the passage of a
Pacific cold front to bring a slightly better chance for
showers/thunderstorms into Monday. Temperatures will generally be 5
to 10 degrees warmer than seasonal averages through Saturday, with a
brief cooling back to near normal associated with the cold frontal
passage on Friday. As the ridge builds into the area, temperatures
will reach 10 to 15 degrees above normal for the latter portion of
the weekend, but they will then cool about 5 to 10 degrees again on
Monday with the passage of the second cold front. Coulston
&&
.AVIATION...
UPDATED 1830Z.
VFR conditions expected across the region through 18Z Tuesday. High
pressure will keep skies mostly clear and winds relatively light.
Scattered moisture moving into far southwest Montana will cause
scattered mid level clouds to develop and linger through around 06Z.
Weak instability there may also cause an isolated shower or
thunderstorm to develop as well. Any development will likely remain
south of a KBZN-KBTM line. Expect a front to move into the region
from the northwest around 18z tomorrow. Low ceilings and strong
northerly winds will move in to KCTB after 18z before moving
east-southeast through the day.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 46 70 44 72 / 0 10 10 20
CTB 44 63 40 70 / 0 10 10 30
HLN 44 72 45 75 / 0 10 20 20
BZN 38 74 41 74 / 10 20 30 20
WEY 33 64 35 65 / 20 40 40 40
DLN 40 71 42 72 / 10 20 30 30
HVR 43 76 42 72 / 0 0 10 20
LWT 41 72 42 68 / 0 10 10 20
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1232 PM CDT MON MAY 6 2013
.SYNOPSIS...
ISSUED AT 407 AM CDT MON MAY 6 2013
H5 ANALYSIS TONIGHT HAS THREE AREAS OF CLOSED LOW
PRESSURE OVER THE CONUS. THE FIRST WAS OVER NRN ALABAMA...THE SECOND
OFF THE NRN CA COAST AND A THIRD WEAKER SYSTEM WAS NOTED OVER
CENTRAL SOUTH DAKOTA. AT THE SURFACE...WEAK HIGH PRESSURE WAS
ANCHORED ACROSS NORTHERN NEBRASKA AND SOUTHERN SOUTH DAKOTA ATTM.
RADIATIONAL COOLING UNDERNEATH THE HIGH...HAS LED TO SOME PATCHY FOG
ACROSS NORTHEASTERN PORTIONS OF THE FORECAST AREA OVER THE PAST
HOUR...WITH VISBYS DOWN TO QUARTER MILE AT ONEILL. COMPARED TO 24
HOURS AGO...TEMPERATURES ARE MUCH WARMER ATTM WITH 3 AM CDT TEMPS
RANGING FROM THE LOWER 30S IN THE NORTHEAST...TO THE LOWER 40S IN
THE EASTERN PANHANDLE AND FAR SOUTHWESTERN NEBRASKA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 407 AM CDT MON MAY 6 2013
THE MAIN FORECAST CHALLENGES OVER THE NEXT 24 HOURS ARE
TEMPERATURES TODAY...AND THE THREAT FOR THUNDERSTORMS LATER
TONIGHT. FOR THIS MORNING...OBSERVATIONS...SATELLITE IMAGERY AND
HIGHWAY CAMS...CONTINUE TO INDICATE FOG ACROSS THE NORTHEASTERN
CWA ATTM. THE LATEST VISIBILITY FOR ONEILL IS AROUND A QUARTER
MILE. DECIDED TO HOIST A DENSE FOG ADVISORY TO COVER THIS THREAT
THROUGH MID MORNING. ATTM...THE DENSE FOG THREAT APPEARS LOCALIZED
WITH THE LOWEST VISBYS IN LOW LYING AREAS AND RIVER VALLEYS. BASED
ON THE HRRR AND NAM12 BL RH FIELD...FOG SHOULD QUICKLY BURN OFF BY
MID MORNING...WITH VISBYS IMPROVING QUICKLY AFTER 14Z. BASED ON
THE HRRR...THE GREATEST THREAT FOR FOG SHOULD REMAIN ALONG AND
EAST OF HIGHWAY 183. FOR THE REMAINDER OF TODAY...SRLY WINDS WILL
INCREASE THIS AFTERNOON AS HIGH PRESSURE MOVES EAST OF THE
AREA...AND LEE TROUGHING DEEPENS ACROSS EASTERN WYOMING AND
EASTERN COLORADO. THE SRLY WINDS...WILL PUSH WARMER AIR AND
INCREASED LOW LEVEL MOISTURE FROM THE SRN PLAINS INTO WESTERN AND
NORTH CENTRAL NEBRASKA. THIS WILL RESULT IN HIGHS IN THE MID TO
UPPER 60S THIS AFTERNOON...WHICH IS A SMALL DECREASE IN THE LOWER
70S IN THE INHERITED FCST. HIGHS WERE LOWERED AS I AM ANTICIPATING
ADDITIONAL HIGH CLOUDINESS TO PUSH INTO THE FORECAST AREA LATER
THIS AFTERNOON FROM THE SRN ROCKIES. THIS CLOUDINESS IS IN ADVANCE
OF AN APPROACHING DISTURBANCE...WHICH WILL BEGIN TO IMPACT THE
FORECAST AREA LATER TONIGHT.
PRECIPITATION CHANCES WILL BEGIN TO INCREASE OVERNIGHT TONIGHT AS
MID LEVEL WAA BEGINS TO LIFT INTO THE CENTRAL PLAINS IN ADVANCE OF
AN APPROACHING UPPER LEVEL DISTURBANCE. ELEVATED INSTABILITY WILL
INCREASE OVERNIGHT PER H800 CALCULATED LI`S RANGE FROM -1 TO -3
OVERNIGHT ACROSS CENTRAL AND NORTHERN NEBRASKA. ADDITIONAL FORCING
FOR TSRAS WILL COME FROM THE DEVELOPMENT OF A 30 KT LLJET WHICH WILL
EXTEND FROM WESTERN KS INTO SWRN NEBRASKA AFTER 06Z TONIGHT.
COVERAGE OF TSRAS IS EXPECTED TO BE LIMITED THOUGH AS SURFACE DEW
POINTS WILL ONLY BE IN THE LOWER TO MID 40S. ATTM...NO SEVERE
THUNDERSTORMS ARE EXPECTED OVERNIGHT...AS LIFT AND AVAILABLE CAPE
WILL BE LIMITED.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 407 AM CDT MON MAY 6 2013
BY TUESDAY MORNING THERE REALLY WON/T BE MUCH MOVEMENT IN THE
PRIMARY UPPER LEVEL SYSTEMS ACROSS THE CONUS. THE UPPER LOW OVER
THE SOUTHEAST PART OF THE COUNTRY WILL HAVE MOVED INTO THE
CAROLINAS...WHILE THE SYSTEM OFF THE CALIFORNIA COAST WILL JUST BE
MOVING ONSHORE BY 12Z TUESDAY. ALSO...THE WEAK UPPER LOW NOW OVER
SOUTH DAKOTA WILL STAY STATIONARY THROUGH TUESDAY MORNING.
MODEL SOLUTIONS HAVE STARTED TO BECOME MORE IN LINE FOR TUESDAY.
THE SYSTEM OVER THE SOUTHEAST WILL SLOWLY LIFT NORTH ALONG THE
EAST COAST THROUGH THE WEEK...WHILE THE CALIFORNIA LOW MOVES
ONSHORE TUESDAY AND INTO THE GREAT BASIN TUESDAY NIGHT.
MEANWHILE...THE WEAK UPPER LOW OVER THE DAKOTAS WILL STAY IN THE
AREA THROUGH AT LEAST TUESDAY NIGHT AS THE NORTHERN STREAM STAYS
WELL TO THE NORTH LEAVING NOTHING TO KICK IT OUT OF THE AREA.
MEANWHILE...A WEAK SHORTWAVE TROUGH EJECTS OUT OF THE WEST COAST
TROUGH AND PUSHES INTO THE CENTRAL PLAINS. PRECIPITATION CHANCES
WILL INCREASE LATER TUESDAY AFTERNOON AND TUESDAY NIGHT AHEAD OF
THE SHORTWAVE TROUGH MOVING INTO THE AREA. MOISTURE WILL BE ON THE
RISE ON TUESDAY AHEAD OF THIS FEATURE AS WELL...WITH THE MODELS
BEING FAIRLY IN TUNE WITH EACH OTHER BRINGING IN 50 DEGREE
DEWPOINTS INTO THE EASTERN PARTS OF THE FORECAST AREA. THIS
MOISTURE ALONG WITH SOME COOLER TEMPERATURES ALOFT /THANKS TO THE
UPPER LOW HANGING AROUND/ WILL CAUSE THE AIR TO BE UNSTABLE FOR
THUNDERSTORMS MAINLY STARTING TUESDAY AFTERNOON. LOOKING FOR QUITE
A BIT OF CLOUD COVER THROUGH THE DAY TUESDAY AND WITH AT LEAST
PERIODIC SHOWERS AND THUNDERSTORMS...NOT EXPECTING TEMPERATURES TO
BE TOO WARM AND ACTUALLY COOLED THEM A FEW DEGREES FROM THE
PREVIOUS FORECAST.
MODEL AGREEMENT CONTINUES THROUGH THE DAY WEDNESDAY AS A SHORTWAVE
MOVING THROUGH THE NORTHERN STREAM DROPS FAR ENOUGH SOUTH TO CATCH
THE DAKOTA UPPER LOW AND FINALLY PUSH IT EASTWARD. AT THIS POINT
THE CALIFORNIA UPPER LOW WILL HAVE MOVED INTO THE FOUR CORNERS.
THIS MAKES WEDNESDAY LOOK DRIER THAN WAS PREVIOUSLY FORECAST AS
THE AREA SITS IN A SUBSIDENT REGION BEHIND THE PASSING UPPER LOW
AND TOO FAR AHEAD OF THE FOUR CORNERS LOW TO REALLY EXPECT MUCH
FOR PRECIPITATION. AT THIS POINT...DIDN/T GO COMPLETELY DRY FOR
WEDNESDAY...AS THERE IS STILL A LACK OF CONFIDENCE IN THE MODEL
SOLUTIONS. AT THIS POINT TRENDED PRECIPITATION FORECAST
LOWER...WITH THE BETTER CHANCES FOR RAIN ACROSS THE SOUTHERN PARTS
OF THE FORECAST AREA. IN TURN...WITH LESSER PRECIPITATION
EXPECTED...INCREASED TEMPERATURES A BIT FOR WEDNESDAY. THERE DOES
LOOK TO BE A WARM FRONT LOCATED SOMEWHERE ACROSS KANSAS ON
WEDNESDAY AFTERNOON...WHICH SHOULD BE THE FOCUS FOR STORM
DEVELOPMENT. INSTABILITY IS DECENT...AND SHEAR IS BETWEEN 35 AND
45KTS SO COULD SEE SOME STRONGER STORMS. THIS BEING SAID...CURRENT
THINKING IS THAT MOST OF THIS ACTIVITY WILL STAY SOUTH OF THE
LOCAL AREA...MAINLY IN FAR SOUTHERN NEBRASKA AND KANSAS. BUT IF
THIS BOUNDARY MEANDERS MAY NEED TO ADJUST THIS THINKING NORTHWARD.
AT THIS POINT MODEL DIVERGENCE BEGINS WITH HOW THE UPPER LOW TO
THE SOUTHWEST WILL PROGRESS. THE ECMWF AND GFS ARE FOR THE MOST
PART BOTH WEAKENING THE LOW AND DEVELOPING ANOTHER OVER NORTHWEST
MEXICO. THE GEM ON THE OTHER HAND QUICKLY PUSHES EVERYTHING TO THE
EAST. CONFIDENCE LESSENS WITH PRECIPITATION CHANCES FOR THURSDAY
AND FRIDAY...BUT THERE REMAINS SOME WEAK SIGNALS SO KEPT IT IN THE
FORECAST FOR NOW.
GOING INTO THE WEEKEND...A STRONG RIDGE BUILDS OVER THE WEST
COAST. IN TURN...AN UPPER LEVEL TROUGH DIGS SOUTH ACROSS THE
NORTHERN PLAINS AND GREAT LAKES REGION. THIS WILL PUSH A PRETTY
STRONG COLD FRONT ACROSS THE AREA...MOST LIKELY SOMETIME SATURDAY
MORNING. MAY HAVE A CHANCE FOR SOME SHOWERS WITH THE FRONTAL
PASSAGE...BUT THE MAIN IMPACT WILL BE AGAIN PUSHING THE NEAR
NORMAL TEMPERATURES SOUTHWARD...WITH TEMPERATURES AROUND 60 OR
LOWER POSSIBLE FOR SATURDAY. ALSO...WITH THE COLDER AND DRIER
AIRMASS ASSOCIATED WITH THIS SYSTEM...COULD ONCE AGAIN SEE LOWS
SUNDAY MORNING IN THE MID 30S OR EVEN LOWER IN SOME LOCATIONS. IN
BOTH CASES...DID NOT GO TO THE EXTREME AS THERE WILL LIKELY BE
SOME CHANGES IN MODEL SOLUTIONS OVER THE NEXT SEVERAL DAYS.
INSTEAD...JUST TRENDED COLDER FOR BOTH PERIODS. THE LONG TERM
MODELS ARE FAIRLY PROGRESSIVE WITH THE UPPER FLOW FOR THE WEEKEND
AND EARLY NEXT WEEK THOUGH SO THIS WOULD INDICATE THIS COLD SPELL
WILL BE QUITE SHORT LIVED...WITH HIGHS RECOVERING TO AROUND 70 FOR
SUNDAY AND POSSIBLY NEARING 80 BY MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1231 PM CDT MON MAY 6 2013
AVIATION CONCERNS FOR THE 18Z TAF PACKAGE INVOLVE SHOWER AND
THUNDERSTORM CHANCES OVERNIGHT AND INTO TUESDAY MORNING. AFTER A
RELATIVELY QUIET MONDAY AFTERNOON AND EVENING AN UPPER LEVEL LOW
PRESSURE SYSTEM WILL BEGIN TO MOVE INTO THE HIGH PLAINS
TONIGHT...WITH SHOWERS AND THUNDERSTORMS POSSIBLE AFTER 06Z. HAVE
LEFT AS -RA FOR NOW TO BRING ATTENTION TO THE CHANCE FOR
PRECIPITATION...HOWEVER UNCERTAINTIES STILL EXIST REGARDING EXACT
TIMING AND WHETHER A -TSRA GROUP WILL BE NEEDED. THIS WILL BE
REFINED AS THE PRECIPITATION CHANCES BECOME CLOSER TO THE CRITICAL
SIX HOUR TIME FRAME. MVFR CIGS WILL BE LIKELY OVERNIGHT AND INTO
TOMORROW MORNING. VISBYS MAY ALSO DROP BELOW VFR IN ANY MODERATE
TO HEAVY SHOWER AND THUNDERSTORM ACTIVITY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...BROOKS
LONG TERM...BROOKS
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1224 PM CDT MON MAY 6 2013
.UPDATE...
ISSUED AT 1223 PM CDT MON MAY 6 2013
NO SUBSTANTIAL CHANGES FOR THIS ESTF UPDATE. DID RAISE HIGH TEMPS
2-3F W OF HWY 183. AM A BIT CONCERNED ABOUT DWPTS MIXING OUT THIS
AFTN...BASED ON LBF RAOB. SEVERAL SITES TO THE W-NW OF THE FCST
AREA AREA ALREADY 15-20% RH. HOWEVER...WEAK PRES GRADIENT PROBABLY
MEANS WE DEAL WITH THE AIR MASS WE HAVE IN PLACE. SO NO CHANGES TO
FCST DWPTS BUT WILL CONT TO MONITOR. DID LOWER SKY COVERAGE SOME.
UPDATE ISSUED AT 717 AM CDT MON MAY 6 2013
SENT A QUICK ENHANCED SHORT-TERM FCST /ESTF/ UPDATE AS HOURLY
TEMPS/DWPTS WERE RUNNING WAY ABOVE REALITY 12-13Z.
STILL SEEING SHALLOW 1/4SM VSBY OR LESS WITHIN THE ADVY. SO NO
CHANGES TO THE HEADLINE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 403 AM CDT MON MAY 6 2013
OVERNIGHT UPPER AIR ANALYSIS INDICATES A MID TO UPPER LEVEL OMEGA
PATTERN WITH MID TO UPPER LEVEL LOWS OVER THE WESTERN AND
SOUTHEASTERN CONUS...AND RIDGING OVER THE CENTRAL CONUS. MID AND
UPPER LEVEL JET ENERGY REMAINS RELEGATED WELL TO OUR SOUTH AND AS
A RESULT...MID AND UPPER LEVEL FLOW OVER THE CENTRAL PLAINS
REMAINS VERY WEAK. WATER VAPOR IMAGERY SHOWS THE TWO
AFOREMENTIONED MID LEVEL LOWS...WITH INCREASED VALUES OF MID LEVEL
MOISTURE WRAPPING AROUND THE SOUTHEASTERN CONUS LOW INTO PORTIONS
OF THE OHIO RIVER VALLEY AND THE MID MISSISSIPPI VALLEY...AND
INCREASED VALUES OF MID LEVEL MOISTURE ALSO NOTED OVER THE WESTERN
CONUS AHEAD OF THE WESTERN CONUS LOW. WATER VAPOR IMAGERY ALSO
INDICATES A SUBTLE MID LEVEL SHORT WAVE OVER THE SOUTHWESTERN
CONUS...PIVOTING TO THE SOUTHEAST OF THE WESTERN CONUS MID LEVEL
LOW. AT THE SURFACE A RIDGE OF HIGH BAROMETRIC PRESSURE EXISTS
FROM NORTH TO SOUTH ACROSS OUR CWA AND AS A RESULT...THE LOW LEVEL
WIND FIELD ACROSS OUR AREA REMAINS LIGHT. THE LIGHT LOW LEVEL WIND
FIELD...WORKING IN CONCERT WITH DECREASING LOW LEVEL DEWPOINT
DEPRESSIONS...HAS PROMOTED THE DEVELOPMENT OF FOG ACROSS MUCH OF
OUR AREA THIS MORNING.
GIVEN THE CURRENT FOG BEING OBSERVED ACROSS THE AREA...WILL
CONTINUE FOG MENTION IN THE FORECAST THROUGH 14Z THIS MORNING. AS
OF 09Z KODX...KHSI AND KAUH HAVE DROPPED TO 1/4SM WITH SEVERAL
OTHER SITE IN THE AREA ALSO DROPPING NEAR 1/4SM. GIVEN ALL
THIS...WENT AHEAD WITH A DENSE FOG ADVISORY...FOR LOCATIONS
GENERALLY EAST OF A KODX TO KEAR LINE AND NORTH OF HIGHWAY 6. THIS
FOG APPEARS TO BE VERY SHALLOW...BASED ON LAPS AND RAP ANALYSIS
POINT SOUNDINGS AS WELL AS OBSERVATION HERE AT THE OFFICE. AS A
RESULT...INCREASED DIABATIC HEATING AND RESULTANT INCREASING
BOUNDARY LAYER DEPTH AND MIXING SHOULD ALLOW THE FOG TO QUICKLY
DISSIPATE POST-SUNRISE...WITH FULL VISIBILITY EXPECTED AT MOST
SITES BY 14Z.
AN OVERALL LACK IN KINEMATIC FORCING IS EXPECTED TO KEEP OUR AREA
DRY TODAY. THE SUBTLE MID LEVEL SHORT WAVE...CURRENTLY OVER THE
SOUTHWESTERN CONUS...IS EXPECTED TO CONTINUE MOVING EAST/NORTHEAST
TODAY AND BY THIS EVENING...SHOULD BE MOVING ACROSS THE SOUTHERN
TO CENTRAL ROCKY MOUNTAIN RANGE. MID LEVEL THERMAL ADVECTION AND
RESULTANT OMEGA AHEAD OF THE SHORT WAVE TROUGH AXIS APPEARS AS
THOUGH IT WILL BE STRONG ENOUGH FOR PRECIPITATION PRODUCTION
ACROSS THE SOUTHERN TO CENTRAL HIGH PLAINS LATE THIS AFTERNOON
INTO THIS EVENING. SHORTLY AFTER SUNSET TONIGHT...A ~30KT 850MB
JET STREAK IS EXPECTED TO DEVELOP FROM SOUTH TO NORTH ACROSS THE
SOUTHERN AND CENTRAL HIGH PLAINS. THIS 850MB JET STREAK IS THEN
EXPECTED TO PROPAGATE EAST SOMEWHAT DURING THE OVERNIGHT HOURS AND
BY 12Z TUESDAY...THE EASTERN PERIPHERY OF THIS 850MB JET AXIS WILL
BRUSH UP AGAINST WEST/SOUTHWESTERN PORTIONS OF OUR CWA. LOW LEVEL
THERMAL ADVECTION ALONG THE 850MB JET STREAK AXIS APPEARS AS
THOUGH IT WILL ALLOW LATE AFTERNOON/EVENING PRECIPITATION ACROSS
THE HIGH PLAINS TO HOLD TOGETHER POST-SUNSET...AND MOVE INTO
WESTERN/SOUTHWESTERN PORTIONS OF OUR CWA 06-12Z TUESDAY. THIS IS A
SOLUTION SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL
GFS...EC AND SREF-MEAN. GIVEN THE MODEL AGREEMENT AND THE APPARENT
LIKELIHOOD THAT SOME LOCATIONS ACROSS OUR WEST/SOUTHWEST COULD
PICKUP UPWARDS OF A TENTH OF AN INCH OF PRECIPITATION...OPTED TO
INCREASE POPS INTO THE 40-50% RANGE ACROSS OUR FAR WEST/SOUTHWEST
06-12Z TUESDAY. LOCATIONS FATHER EAST/NORTHEAST ALSO HAVE POPS IN
PLACE FOR TONIGHT...ALBEIT SUBSTANTIALLY LOWER IN THE 20-30% RANGE
AS CONFIDENCE IS NOT NEARLY AS HIGH THAT FAR EAST WITH THE 850MB
JET STREAK AXIS EXPECTED TO REMAIN FARTHER WEST.
MOISTURE FLUX ALONG THE 850MB JET STREAK AXIS...AS WELL AS THE
700MB JET STREAK AXIS...WORKING IN CONCERT WITH INCREASING MID
LEVEL LAPSE RATES WITH THE APPROACH OF THE SUBTLE MID LEVEL SHORT
WAVE...IS EXPECTED TO PROVIDE INCREASING POTENTIAL INSTABILITY
ACROSS OUR AREA TONIGHT. THE NAM IN PARTICULAR SUGGESTS PARCELS
ROOTED TO BETWEEN 850MB AND 750MB WILL HAVE 50-100J/KG OF CAPE TO
WORK WITH AND CIN RANGING BETWEEN NEAR-ZERO AND AROUND -20J/KG.
GIVEN ALL THIS...ISOLATED CONVECTION CERTAINLY SEEMS POSSIBLE
EMBEDDED WITHIN THE STRATIFORM RAIN EVENT OCCURRING ALONG THE LOW
LEVEL JET AXIS. GIVEN ALL THIS WENT AHEAD AND ADDED ISOLATED
THUNDER MENTION TO THE FORECAST FOR OUR CWA FOR TONIGHT.
THE SURFACE RIDGE CURRENTLY OVER THE AREA IS EXPECTED TO PUSH EAST
LATER TODAY...ALLOWING FOR WEAK LOW LEVEL RETURN FLOW ACROSS MUCH
OF OUR AREA BY THIS AFTERNOON. SUBTLE LOW LEVEL WARM AIR
ADVECTION...AS WELL AS INCREASED DIABATIC HEATING...WHEN COMPARED
TO SUNDAY SHOULD ALLOW FOR A WARMER DAY ACROSS OUR CWA TODAY. AN
AFTERNOON HIGH TEMPERATURE IN THE UPPER 60S TO LOWER 70S IS
FORECAST FOR MOST LOCATIONS FOR TODAY AS A RESULT. INCREASING
CLOUD COVER...POSSIBLE PRECIPITATION...AND CONTINUED SOUTHEASTERLY
LOW LEVEL FLOW SHOULD PRESENT A WARMER OVERNIGHT LOW TEMPERATURE
TONIGHT WHEN COMPARED TO EARLY THIS MORNING. A TUESDAY MORNING LOW
TEMPERATURE IN THE MID TO UPPER 40S IS FORECAST FOR MOST LOCATIONS
ACROSS OUR CWA AS A RESULT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 403 AM CDT MON MAY 6 2013
TUESDAY THROUGH SUNDAY. MAIN FORECAST CONCERNS WILL BE CHANCES FOR
SHOWERS AND THUNDERSTORMS TUESDAY THROUGH SATURDAY AND
TEMPERATURES.
AN UNSETTLED PATTERN WILL BE FOUND ACROSS THE CENTRAL PLAINS FOR
TUESDAY THROUGH SATURDAY. A WEAK RIDGE SETS UP BETWEEN A STRONG
UPPER LEVEL LOW TO THE WEST AND ANOTHER TO THE EAST. DESPITE THE
RIDGE...THERE WILL BE SEVERAL RELATIVELY WEAK UPPER LEVEL LOW
PRESSURE SYSTEMS THAT WILL AFFECT THE AREA FOR THE TUESDAY THROUGH
SATURDAY PERIOD. DO NOT EXPECT THAT IT WILL BE RAINING ALL OF THE
TIME FOR EACH OF THESE PERIODS...BUT THERE IS A CHANCE FOR SHOWERS
AND THUNDERSTORMS ON AND OFF THROUGH THE PERIOD. THE STRONGEST
UPPER LEVEL LOWS THAT MOVE THROUGH THE AREA WILL BE FOR TUESDAY
AND TUESDAY NIGHT AND AGAIN WEDNESDAY NIGHT. THESE WILL BRING THE
BEST CHANCES FOR PRECIPITATION. THE MUCAPE FOR TUESDAY AFTERNOON
AND EVENING WILL REACH AROUND 750 J/KG WHICH SHOULD BE ENOUGH FOR
SOME ISOLATED SEVERE WEATHER...BUT WEDNESDAY AFTERNOON AND EVENING
MUCAPE VALUES APPROACH 2500 J/KG WHICH WOULD INDICATE A BETTER
CHANCE FOR SOME SEVERE STORMS. THERE ARE STILL SOME DIFFERENCES IN
THE MODELS AND WILL HAVE TO WATCH TO SEE HOW MUCH CHANGE THERE IS
OVER THE NEXT COUPLE DAYS.
FOR THURSDAY THROUGH SATURDAY THE UPPER LEVEL LOW IN THE WESTERN
CONUS WILL DRIFT TO THE EAST AND INTO THE PLAINS. THIS WILL
CONTINUE TO BRING CHANCES FOR SHOWERS WITH SOME ISOLATED
THUNDERSTORMS. MU CAPE VALUES DECREASE TO LESS THAN 200 J/KG.
TEMPERATURES SHOULD REMAIN AROUND NORMAL FOR THIS TIME OF YEAR
THROUGH FRIDAY...BUT AS A COLD FRONT MOVES SOUTH INTO THE AREA ON
SATURDAY EXPECT SOME SHOWERS AND THUNDERSTORMS BEHIND THE FRONT
AND TEMPERATURES WILL COOL OFF A FEW DEGREES. A COOL SURFACE HIGH
PRESSURE SYSTEM SETTLES INTO THE REGION FOR SATURDAY NIGHT INTO
SUNDAY AND TEMPERATURES WILL REMAIN A BIT COOLER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1223 PM CDT MON MAY 6 2013
THIS AFTN: VFR WITH A FEW STRATOCU LIFTING TO NEAR 4K FT. LGT AND
VARIABLE WINDS.
TNGT: CLOUDS INCREASE AND DESCEND WITH MID-LVL CIGS AROUND 8K
MOVING IN AFTER 06Z. WINDS ORGANIZE FROM THE SE BELOW 10 KTS.
TUE THRU 18Z: VFR FOR NOW BUT THERE IS POTENTIAL FOR SCT SHWRS TO
RESULT IN A PERIOD OF MVFR CIGS/VSBYS. THERE IS SOME POTENTIAL FOR
THUNDER. SE WINDS WILL CONT BELOW 10 KTS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...BRYANT
LONG TERM...JCB
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
703 PM EDT MON MAY 6 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE NORTHEAST REGION OF THE COUNTRY WILL KEEP
NICE WEATHER OVER THE NORTH COUNTRY INTO THE FIRST HALF OF
WEDNESDAY. FOR THE SECOND HALF OF WEDNESDAY...LOW PRESSURE OVER THE
OHIO VALLEY WILL LIFT SLOWLY NORTHEAST TOWARDS THE AREA. THIS WILL
BRING LIGHT PRECIPITATION LATE WEDNESDAY INTO FRIDAY. A FRONTAL
BOUNDARY WILL TRAVERSE THE AREA FOR THE UPCOMING WEEKEND PROVIDING
THE CHANCE FOR MORE LIGHT PRECIPITATION.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 703 PM EDT MONDAY...PERSISTENCE FORECAST CONTINUES TO BE THE
GENERAL THEME FOR THIS EVENING. HIGH PRESSURE CONTINUES TO REMAIN
IN CONTROL WITH SOUTH/SOUTHEAST SFC WINDS AND CLEAR SKIES. SIMILAR
TO PREVIOUS NIGHTS...NOTICED SEVERAL BUFKIT FORECAST SOUNDINGS
SHOWING A NOCTURNAL LOW-LEVEL JET OF SORTS AROUND 25 KTS OR SO
JUST OFF THE DECK IN THE CHAMPLAIN VALLEY. THIS KEPT SOUTHERLY
WINDS GOING LAST NIGHT IN THE CHAMPLAIN VALLEY...AND WITH LITTLE
CHANGE BETWEEN YESTERDAY AND TODAY HAVE OPTED TO BUMP UP WINDS A
BIT IN THE CHAMPLAIN VALLEY AREA. HAVE ALSO TWEAKED DEWPOINTS
DOWNWARD. CURRENT FORECAST AND VAST MAJORITY OF GUIDANCE SHOWED
HIGHER DEWPOINTS THAN REALITY. HAVE BLENDED MORE OF THE BIAS-
CORRECTED RAP DEWPOINTS WHICH ACTUALLY ARE RUNNING TOO DRY TO
BETTER SHOW THE LOWER DEWPOINTS. THESE WILL EVENTUALLY CLIMB BACK
UP SOME AFTER MIDNIGHT THIS EVENING. NO CHANGES TO
TEMPERATURES...WHICH WILL FALL QUICKLY ONCE AGAIN ESPECIALLY AFTER
SUNSET. TEMPERATURES MAY STAY UP INTO THE 50S IN THE CHAMPLAIN
VALLEY DUE TO THE JET...BUT LOWS IN THE MID/UPPER 30S FOR THE
CUSTOMARY COOLER DACKS/NORTHEAST VERMONT AREAS TO THE 40S FOR THE
REST OF THE NORTH COUNTRY.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 320 PM EDT MONDAY...GOING INTO TUESDAY...THE ENTIRE FORECAST
AREA WILL SEE ANOTHER REPEAT OF WX REGIME GOING ON TODAY. RIDGE
IN PLACE OFF THE NEW ENGLAND COAST FOR ANOTHER DAY. GOING FOR
HIGHS AGAIN IN THE M/U70S IN MOST SPOTS WITH SOME CVLY/SLV LOCALES
NEAR 80F TO L80S. FOR TUESDAY NIGHT...SOME MID/HIGH CLDS FROM LOW
OVER OHIO VALLEY WILL WORK INTO SOUTHERN VERMONT AFT
06Z...OTHERWISE CLR SKIES ABOUND. FIRST HALF OF WEDNESDAY WILL SEE
SFC RIDGE FINALLY BEGIN TO BREAK DOWN AND SHIFT OFFSHORE AS LOW
FROM OHIO VALLEY SHIFTS SLOWLY INTO THE MID-ATLANTIC REGION. WILL
HOLD OFF ON PRECIP FOR MUCH OF THE CWA UNTIL EARLY AFTNOON WHEN
LIGHT -RW WORK INTO SC VT...THEN OVERSPREAD CWA THRU THE OVERNGT
HRS WED. DRY AIRMASS/SUBSIDENCE LEFT BEHIND FROM EXITING
RIDGE...WILL ALLOW MANY SPOTS TO STAY DRY UNTIL AIRMASS BECM
SATURATED ENOUGH TO PRODUCE RAIN. OVERALL QPF NEAR A TENTH OF AN
INCH AT MOST THRU WED NGT.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 425 PM EDT MONDAY...UNSETTLED WEATHER EXPECTED THROUGH THE
PERIOD WITH A CHANCE OF RAIN SHOWERS AND COOLER TEMPERATURES.
THE CLOSED UPPER LOW CURRENTLY OVER THE SOUTHEASTERN U.S. WILL BE OVER
EASTERN PENNSYLVANIA EARLY THURSDAY. THIS UPPER LOW WILL MOVE
NORTHEAST INTO THE GULF OF MAINE BY THURSDAY NIGHT. THIS UPPER LOW
WILL BRING A CHANCE OF RAIN SHOWERS TO THE NORTH COUNTRY THURSDAY
AND FRIDAY. A COLD FRONT WILL MOVE SOUTH INTO THE REGION FROM CANADA
ON FRIDAY AND WILL BRING MORE RAIN SHOWERS TO THE REGION FRIDAY
AND FRIDAY NIGHT. A WARM FRONT WILL APPROACH THE REGION ON SATURDAY
BRINGING ANOTHER CHANCE FOR RAIN SHOWERS TO THE NORTH COUNTRY. A
STRONG COLD FRONT WILL MOVE SOUTHEAST FROM CANADA ON SUNDAY AND
WILL BRING MORE RAIN SHOWERS ALONG WITH MUCH COOLER AIR. ON MONDAY...
ECMWF AND GFS MODELS IN GOOD AGREEMENT IN BRINGING A CLOSED UPPER LOW
THROUGH THE REGION ON MONDAY. 500 MB TEMPERATURES BY MONDAY AFTERNOON
WILL BE -30C TO -35C. HIGH TEMPERATURES ON MONDAY WILL ONLY BE IN
THE 50S...WITH SOME 40S OVER THE HIGHER ELEVATIONS OF THE
ADIRONDACKS AND GREEN MOUNTAINS. HAVE GONE WITH A 30 PERCENT
CHANCE OF SHOWERS FOR MONDAY. GIVEN THE STRONG COLD POOL OF AIR
ALOFT AT 500 MB...WOULD NOT BE SURPRISED TO SEE SMALL HAIL MONDAY AFTERNOON
ALONG WITH AN ISOLATED LOW TOP THUNDERSTORM OR TWO. GIVEN THAT
THIS IS 7 DAYS OUT HAVE NOT INCLUDED THIS IN THE GRIDS AT THIS
TIME.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
THROUGH 00Z WEDNESDAY...VFR TO CONTINUE THROUGH THE PERIOD WITH
LIGHT SOUTH WINDS FOR THIS EVENING. THE EXCEPTION REGARDING WINDS
WOULD BE TONIGHT AT BTV WHERE PRESENCE OF A LOW-LEVEL JET MAY LEAD
TO STRONGER SOUTH WINDS /AROUND 09-12KTS/...AND THEN DURING THE
LATE MORNING/EARLY AFTERNOON TUESDAY DUE TO LAKE BREEZE INFLUENCE
AT PBG AND BTV. EXPECT SOME DIURNAL FAIR WEATHER CUMULUS TO
DEVELOP AT SLK WITH BASES AROUND 6KFT BUT THE REST OF THE TAFS
WILL BE SKC.
OUTLOOK 00Z WEDNESDAY THROUGH SATURDAY...VFR CONDITIONS EXPECTED
TO CONTINUE TUESDAY AND WEDNESDAY AS A RIDGE OF HIGH PRESSURE AT
THE SURFACE AND ALOFT REMAINS OVER THE REGION. A CLOSED UPPER LOW
OVER THE MID ATLANTIC STATES EARLY WEDNESDAY NIGHT WILL MOVE
NORTHEAST AND BRING A CHANCE OF RAIN SHOWERS TO THE REGION
WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...WITH SOME MVFR CONDITIONS
POSSIBLE IN RAIN SHOWERS. A COLD FRONT WILL MOVE INTO THE REGION
ON FRIDAY AND THEN BECOME NEARLY STATIONARY...WITH A CHANCE OF
RAIN SHOWERS FRIDAY AND SATURDAY...WITH SOME AREAS OF MVFR
POSSIBLE.
&&
.FIRE WEATHER...
HIGH PRESSURE OVERHEAD WILL KEEP PRECIP OUT OF THE NORTH
COUNTRY...WITH FULL SUN EXPECTED DURING THE DAY AND RELATIVE
HUMIDITY VALUES FALLING TO 15-25 PERCENT THROUGH TUESDAY. THUS
THE EXTENDED PERIOD OF DRY WEATHER WILL CONTINUE WITH ABOVE NORMAL
TEMPERATURES IN THE 70S TO AROUND 80 DURING THE DAY AND 40S TO LOW
50S AT NIGHT. HAVE MENTIONED THE CONCERNS OF THE VERMONT
DEPARTMENT OF FORESTS...PARKS AND RECREATION REGARDING OPEN
BURNING IN SUCH DRY CONDITIONS IN OUR HAZARDOUS WEATHER OUTLOOK.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JN
NEAR TERM...JN/LOCONTO
SHORT TERM...JN
LONG TERM...WGH
AVIATION...WGH/LOCONTO
FIRE WEATHER...WFO BTV