Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/19/13
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1129 AM MDT WED APR 17 2013
.UPDATE...
&&
.SHORT TERM...OVERALL CURRENT FORECASTS SEEM ON TRACK WITH WARNINGS
AND ADVISORIES STILL LOOK REASONABLE. STRONGER WINDS ACROSS
PLAINS MAY BE DELAYED A FEW HOURS BASED ON LATEST RAP AND HRRR AND
PERHAPS NOT AS STRONG AS CURRENTLY EXPECTED. SNOW TO CONTINUE TO
SPREAD ACROSS PLAINS WHILE CONTINUING INTO THE MOUNTAINS. EXPECTED
SNOW AMOUNTS SEEM ON TRACK...MAY NEED TO ADD A FEW INCHES ACROSS
PLAINS IF HEAVIER BANDS PERSIST. MESSY AFTERNOON/EVENING COMMUTE
STILL ANTICIPATED.
.AVIATION...SNOW PERSISTING ACROSS DENVER AREA WITH OCCASIONAL
BANDS OF MODERATE TO HEAVY SNOW. MVFR CONDITIONS TO PREVAIL WITH
PERIODS OF IFR OR LIFR POSSIBLE WITH THE HEAVIER SNOW. LATEST
MODELS SHOWING LESS WIND AT KDEN...MAY NEED TO DECREASE A BIT.
STILL SOME POTENTIAL FOR BLOWING SNOW. WILL FOLLOW CURRENT TAF
TRENDS AT THIS TIME...THOUGH THE PREVAILING 1/2 MILE FROM 21Z TO
03Z MAY BE A BIT OVERDONE. WILL ADJUST THAT LATER.
&&
.PREV DISCUSSION... /ISSUED 849 AM MDT WED APR 17 2013/
UPDATE...
SHORT TERM...DOES NOT LOOK LIKE BLIZZARD CONDITIONS ARE EXPECTED
TO BE WIDESPREAD ENOUGH ACROSS MUCH OF THE PLAINS: ZONES 42..44..
48>51..TO WARRANT UPGRADING BLIZZARD WATCH TO WARNING AND WILL
HOIST A WINTER STORM WARNING THERE INSTEAD WITH THE POTENTIAL FOR
CONSIDERABLE BLOWING AND DRIFTING SNOW. WIDESPREAD BLIZZARD
CONDITIONS LOOK TO BE MORE PROMISING FOR THE PALMER DIVIDE: ZONES
41 AND 46...SO THE WATCH WAS UPGRADED THERE TO A BLIZZARD WARNING.
NO OTHER CHANGES AT THIS TIME. WILL NEED TO WATCH DENVER AREA FOR
POTENTIAL UPGRADE TO WINTER STORM WARNING. AT THIS TIME...CURRENT
ADVISORY LOOKS OKAY. NO OTHER CHANGES AT THIS TIME. LATEST
OBSERVATIONS AND WEB CAMS SHOW THAT THE MIXED BAG OF FREEZING
RAIN/DRIZZLE AND LIGHT SNOW ALONG THE URBAN CORRIDOR AND ADJACENT
PLAINS BEGINNING TO CHANGE OVER TO ALL SNOW SNOW AS THE DEEPER
MOISTURE AND MID LEVEL ASCENT HAS ARRIVED. SHOULD BE ALL SNOW
SHORTLY.
$$
AVIATION...STILL SOME FREEZING DRIZZLE BEING REPORTED AT
KBJC...WITH ALL SNOW AT KDEN AND KAPA. WITH DEEPER MOISTURE
SPREADING OVER AREA...KBJC SHOULD CHANGE OVER TO ALL SNOW IN THE
BY 16Z. MAY HAVE TO EXTEND THE FREEZING DRIZZLE POTENTIAL THERE
ANOTHER HOUR. NO OTHER CHANGES ANTICIPATED AT THIS TIME.
PREV DISCUSSION... /ISSUED 414 AM MDT WED APR 17 2013/
SHORT TERM...STILL A RATHER COMPLEX WEATHER SCENARIO FOR
NORTHEAST AND NORTH CENTRAL COLORADO. WATER VAPOR LOOP SHOWS A
DEEP BUT ELONGATED UPPER LEVEL TROUGH BEGINNING TO PUSH MORE
EASTWARD ACROSS THE GREAT BASIN AND NORTHERN ROCKIES THIS MORNING.
THERE WAS A LARGE AREA OF MODERATE Q-G VERTICAL MOTION AHEAD OF
THIS TROUGH AXIS...AND THIS WILL SHIFT EAST ACROSS THE FORECAST
AREA TODAY BRINGING WIDESPREAD SNOW.
INITIALLY...THE AIRMASS IS ONLY MOIST IN THE LOW LEVELS OVER THE
PLAINS. THIS WILL KEEP FREEZING DRIZZLE IN THE FORECAST UNTIL
DEEPER MOISTURE AND LIFT ARRIVE LATER THIS MORNING. THERE WERE
SIGNS OF THIS DEEPER MOISTURE ARRIVING FROM THE WEST...WITH
COOLING CLOUD TOPS NOTED THE LAST COUPLE HOURS OVER THE WESTERN
HALF OF COLORADO. THE DEEPER CLOUDS AND SNOW SHOULD ARRIVE ACROSS
THE FRONT RANGE FOOTHILLS BY EARLY/MID MORNING AND THEN SPREAD
EASTWARD OVER THE PLAINS LATER THIS MORNING THROUGH THE AFTERNOON.
WITH REGARD TO SNOW AMOUNTS...THE GFS AND CANADIAN WERE STILL THE
MOST AGGRESSIVE WITH SNOW ACCUMULATIONS WHILE THE NAM AND MOST
MESOSCALE MODELS FOLLOWING THE NAMS LEAD WITH LIGHTER ACCUMS. THE
ECMWF PRETTY MUCH SPLIT THE DIFFERENCE. GIVEN THE ELONGATED TROUGH
AND SOME SIGN OF SPLITTING ENERGY AS SEEN IN THE FORECAST Q-G
VERTICAL MOTION FIELDS LATER THIS AFTERNOON/EVENING...CURRENT
THINKING IS WE WILL END UP CLOSER TO THE SLIGHTLY LOWER
EC/NAM/SREF AVERAGES. DESPITE THIS...WE MAY STILL END UP WITH A
SIGNIFICANT WINTER WEATHER EVENT GIVEN A COUPLE FACTORS.
ONE...THERE IS ALREADY SNOW COVERING THE GROUND ALONG AND NORTH OF
THE I-76 CORRIDOR SO ANY NEW SNOW THAT FALLS WILL BE EASILY BLOWN
ABOUT. TWO...STRONG NORTH WINDS OF 20-30 MPH WITH GUSTS TO 40-50
MPH CAN BE EXPECTED ON THE PLAINS. THIS SHOULD CREATE CONSIDERABLE
BLOWING/DRIFTING SNOW AND NEAR BLIZZARD CONDITIONS ESPECIALLY IN
LOCALES WITH PRE-EXISTING SNOW COVER. THERE IS STILL CONSIDERABLE
UNCERTAINTY WITH REGARD TO IMPACTS AT THIS TIME SO WILL MAINTAIN
A BLIZZARD WATCH FOR THE EASTERN PLAINS WITH POSSIBLE MARGINAL
SNOW ACCUMULATIONS IN AREAS THAT HAVE LITTLE/NO PRE-EXISTING SNOW
COVER.
IN THE FRONT RANGE METRO AREAS...WINDS WILL LIKELY BE STRONG
ENOUGH TO PRODUCE CONSIDERABLE BLOWING/DRIFTING SNOW AND HIGHER
IMPACTS GIVEN EXISTING SNOW COVER AND COLDER TEMPERATURES ALLOWING
FOR MORE SNOW ACCUMULATION ON ROADS. THIS WILL VERY LIKELY DEPEND
ON SNOW INTENSITY BUT THERE IS STILL SOME POTENTIAL FOR AN UPGRADE
OF THE ADVISORY TO A WINTER STORM WARNING. THE AFTERNOON COMMUTE
LOOKS NASTY.
THE ONLY CHANGE TO CURRENT HIGHLIGHTS WILL BE TO DELAY THE START
TIME A COUPLE HOURS FOR LOCATIONS EAST OF I-25 GIVEN A SLIGHTLY
SLOWER ARRIVAL OF DEEPER MOISTURE.
LONG TERM...THE DEPARTING STORM SYSTEM WILL LEAVE THE STATE UNDER
NORTHWEST FLOW THURSDAY. SOME MOISTURE WILL STILL BE EXITING THE
STATE AND WILL LIKELY SEE SOME LIGHT SNOW REMAINING OVER THE FAR
EASTERN PLAINS IN THE MORNING AS WELL AS SOME OROGRAPHIC SNOW
LASTING OVER THE MOUNTAINS THROUGH THE AFTERNOON. TEMPERATURES
WILL STAY COLD...IN THE 30S FOR THE PLAINS AND IN THE 20S FOR THE
MOUNTAINS. NORTHERLY WINDS WILL STILL BE A BIT STRONG DURING THE
DAY...AROUND 15 TO 25 MPH WITH SOME GUSTS AS HIGH AS 40 MPH OVER
THE PLAINS...WHICH WILL CAUSE AREAS OF BLOWING SNOW. THOSE WINDS
SHOULD DIMINISH IN THE EVENING EXCEPT WHERE THEY WILL BE STAYING
GUSTY OUT OF THE WEST IN THE FOOTHILLS.
FRIDAY WILL SEE A SLIGHT WARM UP AND MAINLY DRY WEATHER...BUT
MOISTURE WILL BE INCREASING OVER THE NORTHERN MOUNTAINS LATER IN
THE DAY THROUGH THE NIGHT AS A WEAK DISTURBANCE NEARS THE STATE IN
THE NORTHWEST FLOW. TEMPERATURES SHOULD WARM SIGNIFICANTLY WITH
WARM ADVECTION MOVING IN...AND THE INTENSE APRIL SUN HELPING TO
MELT ANY REMAINING SNOW. READINGS OF UPPER 40S TO NEAR 50 OVER THE
PLAINS AND LOW TO MID 30S FOR THE MOUNTAINS ARE EXPECTED. STILL
ABOUT 10 DEGREES COOLER THAN NORMAL. THE WEAK DISTURBANCE IS
EXPECTED TO INCREASE SHOWERS OVER THE MOUNTAINS AND BRING A SLIGHT
CHANCE OF RAIN SHOWERS TO THE PLAINS SATURDAY AFTERNOON.
TEMPERATURES WILL BE SLIGHTLY WARMER THAN FRIDAY.
SUNDAY...A STRONGER DISTURBANCE WILL BE MOVING OVER THE NORTHERN
ROCKIES AND NEARING THE STATE IN THE NORTHWEST FLOW ALOFT. THIS
DISTURBANCE IS THEN EXPECTED...AS PROGGED BY THE GFS...ECMWF AND
GEM...TO DEEPEN AND DROP SOUTH OVER THE STATE BY MONDAY. THIS WILL
BRING YET ANOTHER ROUND OF COLDER TEMPERATURES AND A CHANCE OF
SNOW FORECAST AREA WIDE STARTING SUNDAY AND LASTING INTO
TUESDAY. HAVE INCREASED POPS FOR THIS PERIOD AND LOWERED
TEMPERATURES TO SHOW THIS BETTER CONFIDENCE IN THE FORECAST. SEEMS
LIKE THE ONGOING ACTIVE WEATHER PATTERN OF APRIL WILL CONTINUE
INTO NEXT WEEK.
AVIATION...LIGHT FREEZING DRIZZLE/FLURRIES WILL CONTINUE EARLY
THIS MORNING WITH MORE WIDESPREAD AND HEAVIER SNOW THEN DEVELOPING
LATE THIS MORNING INTO EARLY AFTERNOON. IFR/LIFR CONDITIONS WILL
PREVAIL. CYCLONIC CONVERGENCE ZONE WILL FLUSH SOUTH WITH ARRIVAL
OF COLD FRONT BY EARLY AFTERNOON WITH STRONGER NORTH WINDS WITH
GUSTS UP TO 30-35 KTS...STRONGEST AT KDEN. CONSIDERABLE
BLOWING/DRIFTING SNOW EXPECTED WITH STRENGTH OF WINDS. SNOW SHOULD
DECREASE AFTER 03Z-06Z WITH AN ENDING 09Z-12Z AND VFR CONDITIONS
DEVELOPING. TOTAL SNOW ACCUMULATIONS MOST LIKELY WILL BE IN THE
4-6 INCH RANGE.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM MDT THURSDAY FOR COZ042-044-
045-048>051.
WINTER STORM WARNING UNTIL MIDNIGHT MDT TONIGHT FOR COZ031-033-
035.
WINTER WEATHER ADVISORY UNTIL 10 PM MDT THIS EVENING FOR COZ030-
032-034.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR COZ036-
038-039.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR COZ040-
043.
BLIZZARD WARNING UNTIL 6 AM MDT THURSDAY FOR COZ041-046.
&&
$$
SHORT TERM...D-L
LONG TERM....KRIEDERMAN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS TAUNTON MA
157 AM EDT WED APR 17 2013
.SYNOPSIS...
SCATTERED SHOWERS AND PERHAPS AN ISOLATED THUNDERSTORM WILL MOVE
ACROSS THE REGION WITH A COLD FRONT TONIGHT. DRY PLEASANT WEATHER
FOLLOWS WEDNESDAY INTO THURSDAY AS HIGH PRESSURE BUILDS ACROSS
NORTHERN NEW ENGLAND. A WARM FRONT MAY BRING A FEW PASSING SHOWERS
TO THE REGION THU NIGHT AND FRI. A PERIOD OF HEAVY RAIN WITH
PERHAPS A FEW THUNDERSTORMS ARE EXPECTED FRI NIGHT INTO SAT...WITH
DRIER/COOLER WEATHER FOLLOWING SUN AND MON.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
2 AM UPDATE...
THE EVOLUTION AND CHARACTERISTICS OF SHOWER ACTIVITY AHEAD OF AN
APPROACHING COLD FRONT HAS PROVEN DIFFICULT TO FORECAST. FEEL THE
LATEST RAP GUIDANCE HAS THE BEST HANDLE /EARLIER 16.12Z ECMWF MAY
BE A CLOSE SECOND/. EXPECT WIDELY SCATTERED SHOWERS TO IMPACT
SOUTHERN NEW ENGLAND INTO THE MORNING BY WHICH POINT THE COLD
FRONT SHOULD HAVE SWEPT THROUGH THE REGION MOVING SOUTH AND OUT TO
SEA. WILL CONTINUE WITH A MENTION OF ISOLATED THUNDER WITH
CONVECTIVE INDICES JUST ON THE CUSP.
TEMPERATURES AND DEWPOINTS REMAIN ON TRACK ALBEIT A DEGREE OR TWO
WARMER IN SOME AREAS THAN PRESENTLY FORECASTED. THE SLUGGISHNESS
OF THE COLD FRONT TO MOVE THROUGH THE REGION WILL LIKELY HAVE
IMPLICATIONS OF KEEPING TEMPERATURES MILDER THAN ORIGINALLY
THOUGH...ALLOWING WARMER CONDITIONS FOR TOMORROW.
WILL CONTINUE WITH MINIMUM TEMPERATURES TONIGHT AROUND THE MID TO
UPPER 40S. COLDEST SPOTS WILL BE THE HIGHER ELEVATIONS OF THE
BERKSHIRES AND MONADNOCKS /UPPER 30S/. WARMEST LOCALES ALONG THE
SHORES. SOUTHWESTERLY FLOW WILL REMAIN BLUSTERY AT TIMES AHEAD OF
THE COLD FRONT BACKING WEST-NORTHWEST WITH PASSAGE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
WEDNESDAY...
WITH UPPER LEVEL PATTERN BECOMING SOMEWHAT ZONAL ACROSS THE
NORTHEASTERN U.S...THE COLD FRONT WILL STALL S OF THE REGION.
HOWEVER...IT WILL BE FAR ENOUGH OFFSHORE THAT DRY CONDITIONS WILL
BE IN PLACE. MID AND HIGH CLOUDS WILL LINGER ACROSS SOUTHERN
AREAS WITH THE STALLED FRONT TO THE S. HIGH PRES WILL SLOWLY MOVE
ACROSS NORTHERN NEW ENGLAND DURING THE DAY...SO WINDS WILL BECOME
LIGHT N-NE. EXPECT DAYTIME HIGHS IN THE LOWER-MID 60S...EXCEPT IN
THE MID-UPPER 50S ALONG THE COAST.
WEDNESDAY NIGHT...
THE HIGH WILL MOVE ACROSS MAINE/EASTERN QUEBEC AS LOW PRES
DEVELOPS ACROSS THE MID MISSISSIPPI VALLEY. WILL SEE ANOTHER DRY
NIGHT...WITH MAINLY CLEAR SKIES ESPECIALLY ACROSS S NH AND N MA
WITH SOME MID AND HIGH CLOUDS LINGERING ACROSS THE S COAST. THE
CLOUDS WILL START TO INCREASE AFTER MIDNIGHT AS THE STALLED FRONT
TO THE S WILL START TO PUSH N AS A WARM FRONT. WILL BE A CHILLY
NIGHT ACROSS S NH WITH OVERNIGHT LOWS IN THE MID-UPPER 30S...
RANGING TO THE LOWER-MID 40S ALONG THE S COAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
HIGHLIGHTS...
* FEW SHOWERS THU NIGHT INTO FRI AFTERNOON BUT NOT A WASHOUT
* HEAVY RAIN AND ISOLATED THUNDER LATE FRI NIGHT INTO SAT
* DRY WEATHER WITH BELOW NORMAL TEMPS SUN AND MON
DETAILS...
THURSDAY...
UPPER LEVEL RIDGING SHOULD RESULT IN A PLEASANT DAY. SOME
SUNSHINE IS EXPECTED AT LEAST FOR THE FIRST PART OF THE DAY...BUT
CLOUDS WILL INCREASE A BIT FROM THE WEST DURING THE AFTERNOON.
HIGHS SHOULD TOP OUT IN THE UPPER 50S AND LOWER 60S ACROSS MOST
LOCATIONS...BUT IT MAY BE SEVERAL DEGREES COOLER ALONG THE
IMMEDIATE COAST AS A RESULT OF SEA BREEZES.
THURSDAY NIGHT AND FRIDAY...
THE BEST DYNAMICS/FORCING WILL REMAIN WELL TO OUR WEST THU NIGHT
INTO FRI AFTERNOON. HOWEVER...A STRONG SOUTH TO SOUTHWEST LOW
LEVEL JET WILL RESULT IN WARM ADVECTION AND SOME MID LEVEL LIFT
INTO SOUTHERN NEW ENGLAND. THIS MAY RESULT IN A FEW SHOWERS FROM
TIME TO TIME...BUT CERTAINLY FAR FROM A WASHOUT AND MOST OF THE
TIME DRY WEATHER SHOULD DOMINATE. AS FOR TEMPS...DESPITE SOME
CLOUDS AROUND STRONG WARM ADVECTION SHOULD PUSH HIGHS FRI INTO THE
UPPER 60S AND LOWER 70S ACROSS MUCH OF THE REGION.
LATE FRIDAY NIGHT AND SATURDAY...
STILL A WAYS OUT...BUT THERE ARE SOME GOOD INDICATORS FOR A
PERIOD OF HEAVY RAINFALL ALONG WITH ISOLATED THUNDER AS A STRONG
COLD FRONT MOVES THROUGH THE REGION. DEEP MERIDIONAL FLOW SHOULD
RESULT IN PWAT VALUES OF AROUND 1.5 INCHES. STRONG FORCING/LIFT
SHOULD COMBINED WITH THE HIGH PWAT VALUES FOR A PERIOD OF HEAVY
RAINFALL. TIMING IS STILL TRICKY...BUT CURRENT INDICATIONS ARE FOR
LATE FRI NIGHT INTO MID AFTERNOON SAT FOR THE MAIN AFFECTS. AT
THIS TIME...THE FRONT LOOKS PROGRESSIVE ENOUGH TO PREVENT A
SIGNIFICANT FLOOD EVENT. HOWEVER...NUISANCE POOR DRAINAGE STREET
FLOODING IS CERTAINLY A POSSIBILITY.
AS FOR CONVECTIVE CHANCES...INSTABILITY PARAMETERS DON/T LOOK TO BE
ENOUGH FOR SEVERE WEATHER...BUT CERTAINLY COULD BE SOME ISOLATED
EMBEDDED THUNDER SO HAVE INCLUDED IN THE FORECAST. ALSO...WITH
THE STRONG LOW LEVEL JET THERE IS A LOW PROBABILITY THAT BRIEF
WIND ADVISORY CRITERIA IS MET.
SUNDAY AND MONDAY...
LARGE HIGH PRESSURE WILL BUILD INTO THE REGION RESULTING IN DRY
WEATHER BUT TEMPERATURES A BIT BELOW NORMAL FOR THE LATTER HALF OF
APRIL.
MONDAY NIGHT AND TUESDAY...
LOW CONFIDENCE BUT IF A WAVE OF LOW PRESSURE GETS CLOSE ENOUGH TO
US WE COULD HAVE A COLD RAIN. IF IT STAYS MORE OUT TO SEA THEN
WILL REMAIN DRY. JUST TOO EARLY TO SAY MUCH MORE AT THIS POINT SO
SOME LOW POPS IN THE FORECAST.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...
* MODERATE CONFIDENCE INTO MORNING...
* HIGH CONFIDENCE WEDNESDAY INTO WEDNESDAY NIGHT...
* MODERATE CONFIDENCE THURSDAY...
SCT -SHRA DIFFICULT TO FORECAST RESULTING IN MODERATE CONFIDENCE.
WILL PREVAIL WITH VCSH. LESSER CONFIDENCE CONCERNING MVFR CIGS AND
VSBY IMPACTS. SHOULD ANY -SHRA IMPACT TERMINALS...A BRIEF PERIOD
OF MVFR VSBYS IS CERTAINLY PLAUSIBLE. 2-3 KFT AGL 50 KT SW JET PER
BOS TDWR. LLWS TO IMPACT TERMINALS S AND E OF IJD-TAN-GHG INTO THE
MORNING.
THEREAFTER...VFR FOR WEDNESDAY INTO WEDNESDAY NIGHT. TWO CONCERNS...
SEA-BREEZES ALONG ALL SHORELINES AROUND 18Z...AND THE POSSIBILITY
FOR ISOLATED PATCHY FOG OVERNIGHT. HIGHER CONFIDENCE FOR THE PRIOR
OVER THE LATTER. WILL SEE INCREASING CLOUDS AND THE CHANCE OF
-SHRA INTO LATE THURSDAY FROM THE SW. FEEL VFR WILL PREVAIL.
KBOS TERMINAL...MODERATE CONFIDENCE.
UNCERTAINTY OVER -SHRA SO WILL PREVAIL VCSH. ANTICIPATING SEA-
BREEZE IMPACTS AROUND 18Z WITH WINDS BECOMING 090...REVERTING NE
AFTER DUSK.
KBDL TERMINAL...MODERATE CONFIDENCE.
WILL PREVAIL WITH VCSH UNDER SIMILAR CIRCUMSTANCES AT KBOS ABOVE.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
THURSDAY NIGHT THROUGH SATURDAY...MODERATE CONFIDENCE. PERIODS OF
MVFR-IFR CONDITIONS IN SCATTERED SHOWERS/LOW CLOUDS AND FOG
PATCHES. ISOLATED THUNDER AND LLWS ARE POSSIBILITIES FRI NIGHT/SAT
MORNING
SATURDAY NIGHT THROUGH SUNDAY...MODERATE CONFIDENCE IN MAINLY VFR
CONDITIONS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...HIGH CONFIDENCE THROUGH WEDNESDAY NIGHT.
TONIGHT...CONTINUED SMALL CRAFT WITH SW GUSTS UP TO 25-30 KT. MAY
SEE BRIEFLY HIGHER GUSTS IN ANY HEAVY DOWNPOURS OR TSTMS. WINDS
START TO DIMINISH AFTER MIDNIGHT AS FRONT PASSES AND SHIFT TO
W-NW.
WEDNESDAY...ANY LEFTOVER SMALL CRAFT GUSTS AND SEAS DIMINISH
QUICKLY WED MORNING. EXPECT NW WINDS TO SHIFT TO N-NE AND CONTINUE
TO DIMINISH AS HIGH PRES BUILDS N OF THE WATERS.
WEDNESDAY NIGHT...WINDS AND SEAS BELOW SMALL CRAFT CRITERIA.
OUTLOOK...THURSDAY THROUGH SUNDAY...
MODERATE TO HIGH CONFIDENCE THROUGH THE PERIOD.
THURSDAY AND FRIDAY...PERSISTENT SOUTHERLY FLOW AND LONG FETCH WILL
RESULT IN SEAS BUILDING TO SCA LEVELS OVER MOST OPEN WATERS THU
NIGHT/FRI. IN ADDITION...SCA WIND GUSTS WILL BE POSSIBLE AT TIMES
ESPECIALLY NEAR SHORE THU AND FRI AFTERNOON/S. AREAS OF FOG MAY
AFFECT THE WATERS THU NIGHT INTO FRI MORNING.
FRIDAY NIGHT AND SATURDAY...STRONG SOUTHWEST SCA WIND GUSTS ARE
EXPECTED AHEAD OF AN APPROACHING COLD FRONT. MAY EVEN BE A BRIEF
PERIOD OF MARGINAL GALE FORCE SOUTHWEST WIND GUSTS. SEAS SHOULD
APPROACH 10 FEET ACROSS THE SOUTHERN EASTERN ATLANTIC WATERS.
AREAS OF FOG AND PERHAPS EVEN AN ISOLATED THUNDERSTORM OR TWO WILL
BE POSSIBLE.
SATURDAY NIGHT AND SUNDAY...A PERIOD OF WESTERLY SCA WIND GUSTS ARE
POSSIBLE BEHIND THE STRONG COLD FRONT.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT EARLY THIS MORNING FOR
ANZ230>234-236.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR ANZ235-
237-250-251-254>256.
&&
$$
SYNOPSIS...FRANK/EVT
NEAR TERM...SIPPRELL
SHORT TERM...EVT
LONG TERM...FRANK
AVIATION...FRANK/SIPPRELL
MARINE...FRANK/EVT
AREA FORECAST DISCUSSION
NWS MIAMI FL
150 PM EDT WED APR 17 2013
.AVIATION...VFR WILL PREVAIL. SHOWERS ARE OVER THE SOUTHERN TIP OF
THE PENINSULA AND EXPECTED TO STAY THERE WITH A SLIGHT CHANCE OF
SHOWERS, AND PERHAPS A THUNDERSTORM, ALONG THE GULF COAST, BUT
GIVEN SUCH LOW PROB`S OF TSRA, DECIDED TO JUST KEEP VCSH FOR KAPF
AND ELSEWHERE NO MENTION. NE WINDS WILL BECOME ESE ON THURSDAY
WITH SPEEDS 10-15 KT, DECREASING BY ABOUT 5 KT OVERNIGHT, THEN
BECOMING ESE AROUND 10 KT ON THU. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 957 AM EDT WED APR 17 2013/
UPDATE...
LATEST RADAR IMAGERY CONTINUES TO SHOW SCATTERED LIGHT TO MODERATE
SHOWERS PUSHING SOUTHWEST ACROSS BISCAYNE BAY. LATEST HRRR AND
LOCAL SHORT RANGE MODELS KEEP THESE SHOWERS MAINLY ALONG AND SOUTH
OF U.S. HIGHWAY 41 THROUGH MUCH OF THE AFTERNOON. UPDATED POP AND
SKY GRIDS TO ACCOUNT FOR THIS. ALSO ADJUSTED TEMPERATURES
SLIGHTLY. UPDATE WILL BE SENT SHORTLY.
PREV DISCUSSION... /ISSUED 739 AM EDT WED APR 17 2013/
AVIATION...VFR WILL PREVAIL. A BRIEF SHOWER CANNOT BE RULED OUT
EAST COAST, BUT COVERAGE LOOKS SPARSE ENOUGH THROUGH THE PERIOD TO
PRECLUDE VCSH MENTION IN THE TAFS. HOWEVER, A GULF SEA BREEZE
DEVELOPING AT KAPF COULD ALLOW FOR A FEW SHOWERS, AND POSSIBLY A
TSTORM TO DEVELOP. FOR NOW INCLUDE VCSH THERE. WINDS WILL PREVAIL
OUT OF THE NE BECOMING EAST INCREASING TO 10-15KT THIS AFTERNOON,
EXCEPT THE SW GULF SEA BREEZE DEVELOPING AT KAPF MID AFTERNOON.
/GREGORIA
PREV DISCUSSION... /ISSUED 409 AM EDT WED APR 17 2013/
SHORT TERM (TODAY-FRIDAY)...
THE LATEST NUMERICAL MODEL GUIDANCE REMAINS IN GOOD AGREEMENT
THROUGH THE SHORT-TERM PERIOD AND INDICATES THE UPPER RIDGE HOLDING
IN PLACE THROUGH TONIGHT...THEN GRADUALLY WEAKENING AND SHIFTING
EAST OVER THE WESTERN ATLANTIC AHEAD OF AN APPROACHING UPPER TROUGH
BY FRIDAY. AT THE SURFACE...THE LATEST IR LOOP AND ASCAT PASS SHOWED
A WEAK LOW CENTERED NNE OF THE BAHAMAS WITH A WEAK BOUNDARY
EXTENDING SW TOWARD SOUTH FLORIDA. THIS WEAK BOUNDARY COMBINED WITH
LIGHT EASTERLY LOW-LEVEL FLOW WILL KEEP A SLIGHT CHANCE OF MAINLY
LIGHT SHOWERS OVER THE ADJACENT ATLANTIC WATERS AND ALONG THE EAST
COAST AREAS THROUGH THE EARLY MORNING HOURS. SIMILAR TO
YESTERDAY...THE BEST CHANCE FOR AFTERNOON SHOWERS WILL REMAIN INLAND
TOWARD THE GULF COAST AS THE WEST COAST SEA BREEZE BEGINS TO
DEVELOP. THE LATEST MODEL SOUNDINGS OVER THESE INTERIOR AREAS ARE
SIMILAR TO YESTERDAY...HOWEVER...INDICATE DRIER AIR THROUGH THE
MID/UPPER LEVELS (PWAT VALUES AROUND 1.4") WITH THE BEST SOURCE OF
MOISTURE REMAINING WITHIN THE LOWER 5-10 KFT. AS A RESULT...
CONFIDENCE IN ANY DEEP MOIST CONVECTION OR THUNDERSTORM DEVELOPMENT
IS LOW. HOWEVER...A STORM OR TWO CAN NOT BE COMPLETELY RULED OUT
TODAY AS TEMPERATURES CLIMB BACK INTO THE LOWER 90S AND DEWPOINTS
REMAIN IN THE MID TO UPPER 60S. ON THURSDAY...THE LOW-LEVEL FLOW
WILL BEGIN TO SHIFT TOWARD THE SOUTHEAST...WHICH WILL TRANSLATE TO
THE BEST AFTERNOON SHOWER/TSTM CHANCES OVER THE NORTHWEST INTERIOR
OR FROM NAPLES TO THE LAKE REGION. ELSEWHERE...THE WARM CONDITIONS
WILL PERSIST WITH AFTERNOON HIGHS CLIMBING BACK INTO THE LOWER 80S
NEAR THE EAST COAST TO THE LOWER 90S INLAND. OVERNIGHT LOWS ARE
FORECAST TO RANGE FROM THE UPPER 60S INLAND TO THE LOW TO MID 70S
OVER THE EAST COAST AND METRO AREAS (SEVERAL DEGREES ABOVE THE
NORMAL LOWS) EACH NIGHT. ON FRIDAY...A COLD FRONT ASSOCIATED WITH
THE PREVIOUSLY MENTIONED UPPER TROUGH WILL BEGIN TO APPROACH THE
STATE. MOST OF THE SHOWERS/TSTM COVERAGE...HOWEVER...SHOULD REMAIN
NORTH OF OUR AREA THROUGH THE AFTERNOON PERIOD. PATCHY FOG WILL
REMAIN POSSIBLE EACH NIGHT...MAINLY OVER THE INTERIOR AREAS...WHICH
LINES UP WELL WITH THE LATEST SHORT-RANGE ENSEMBLE GUIDANCE.
LONG TERM (FRIDAY NIGHT-WEDNESDAY)...
THE EXTENDED GUIDANCE REMAINS IN DECENT AGREEMENT AND SHOWS THE
UPPER RIDGE CONTINUING TO SHIFT EAST OVER THE WESTERN ATLANTIC AS A
BROAD UPPER TROUGH SHIFTS EAST OVER THE REGION. A COLD FRONT
ASSOCIATED WITH THIS UPPER FEATURE IS FORECAST TO APPROACH AND BEGIN
TO IMPACT THE STATE OVER THE WEEKEND. INCREASING DEEP LAYER MOISTURE
COMBINED WITH THE APPROACHING FRONT/UPPER TROUGH WILL TRANSLATE TO
INCREASING RAINFALL CHANCES THROUGH THIS TIME. DEEP LAYER SOUTHWEST
FLOW WILL FAVOR ENHANCED ACTIVITY OVER THE EAST COAST
AREAS...ESPECIALLY FROM BROWARD COUNTY TO THE LAKE REGION. AS THE
FORECAST CONFIDENCE CONTINUES TO INCREASE THROUGH THE MID-WEEK
PERIOD...WE WILL BEGIN TO REFLECT THIS WITH INCREASING RAINFALL
CHANCES...ESPECIALLY FOR SATURDAY AND SUNDAY. CONFIDENCE BEYOND THIS
PERIOD INTO THE UPCOMING WEEK BEGINS TO DECREASE DUE TO SOME MODEL
DIFFERENCES. TEMPERATURES ARE FORECAST TO REMAIN AROUND OR SLIGHTLY
ABOVE NORMAL THROUGH THE PERIOD.
MARINE...
LIGHT TO MODERATE EASTERLY WINDS WILL BEGIN TO SHIFT TO THE
SOUTHEAST THURSDAY THROUGH FRIDAY AHEAD OF AN APPROACHING FRONTAL
BOUNDARY. THE COLD FRONT WILL LEAD TO INCREASING RAINFALL CHANCES
FRIDAY THROUGH THE UPCOMING WEEKEND AS THE BOUNDARY STALLS NEAR OR
OVER THE AREA. WINDS WILL SHIFT BACK TO THE EAST LATER IN THE
WEEKEND AND INTO THE UPCOMING WEEK AS THE FRONT WEAKENS AND HIGH
PRESSURE BUILDS BACK OVER THE REGION.
FIRE WEATHER...
PLENTY OF MOISTURE WITH DEWPOINTS REMAINING IN THE MID 60S WILL
KEEP RELATIVE HUMIDITIES WELL ABOVE CRITICAL LEVELS THROUGH THE
AFTERNOON PERIODS. LOW-LEVEL FLOW WILL REMAIN OUT OF THE EAST AND
SOUTHEAST WITH THE BEST CHANCE FOR AFTERNOON SHOWERS AND POSSIBLY
A STORM OR TWO REMAINING OVER THE INTERIOR LOCATIONS TOWARD THE
GULF COAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 73 83 74 / 10 - 10 10
FORT LAUDERDALE 82 76 84 77 / 10 - 10 20
MIAMI 84 73 85 75 / 20 - 10 10
NAPLES 88 69 88 70 / 10 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
957 AM EDT WED APR 17 2013
.UPDATE...
LATEST RADAR IMAGERY CONTINUES TO SHOW SCATTERED LIGHT TO MODERATE
SHOWERS PUSHING SOUTHWEST ACROSS BISCAYNE BAY. LATEST HRRR AND
LOCAL SHORT RANGE MODELS KEEP THESE SHOWERS MAINLY ALONG AND SOUTH
OF U.S. HIGHWAY 41 THROUGH MUCH OF THE AFTERNOON. UPDATED POP AND
SKY GRIDS TO ACCOUNT FOR THIS. ALSO ADJUSTED TEMPERATURES
SLIGHTLY. UPDATE WILL BE SENT SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 739 AM EDT WED APR 17 2013/
AVIATION...VFR WILL PREVAIL. A BRIEF SHOWER CANNOT BE RULED OUT
EAST COAST, BUT COVERAGE LOOKS SPARSE ENOUGH THROUGH THE PERIOD TO
PRECLUDE VCSH MENTION IN THE TAFS. HOWEVER, A GULF SEA BREEZE
DEVELOPING AT KAPF COULD ALLOW FOR A FEW SHOWERS, AND POSSIBLY A
TSTORM TO DEVELOP. FOR NOW INCLUDE VCSH THERE. WINDS WILL PREVAIL
OUT OF THE NE BECOMING EAST INCREASING TO 10-15KT THIS AFTERNOON,
EXCEPT THE SW GULF SEA BREEZE DEVELOPING AT KAPF MID AFTERNOON.
/GREGORIA
PREV DISCUSSION... /ISSUED 409 AM EDT WED APR 17 2013/
SHORT TERM (TODAY-FRIDAY)...
THE LATEST NUMERICAL MODEL GUIDANCE REMAINS IN GOOD AGREEMENT
THROUGH THE SHORT-TERM PERIOD AND INDICATES THE UPPER RIDGE HOLDING
IN PLACE THROUGH TONIGHT...THEN GRADUALLY WEAKENING AND SHIFTING
EAST OVER THE WESTERN ATLANTIC AHEAD OF AN APPROACHING UPPER TROUGH
BY FRIDAY. AT THE SURFACE...THE LATEST IR LOOP AND ASCAT PASS SHOWED
A WEAK LOW CENTERED NNE OF THE BAHAMAS WITH A WEAK BOUNDARY
EXTENDING SW TOWARD SOUTH FLORIDA. THIS WEAK BOUNDARY COMBINED WITH
LIGHT EASTERLY LOW-LEVEL FLOW WILL KEEP A SLIGHT CHANCE OF MAINLY
LIGHT SHOWERS OVER THE ADJACENT ATLANTIC WATERS AND ALONG THE EAST
COAST AREAS THROUGH THE EARLY MORNING HOURS. SIMILAR TO
YESTERDAY...THE BEST CHANCE FOR AFTERNOON SHOWERS WILL REMAIN INLAND
TOWARD THE GULF COAST AS THE WEST COAST SEA BREEZE BEGINS TO
DEVELOP. THE LATEST MODEL SOUNDINGS OVER THESE INTERIOR AREAS ARE
SIMILAR TO YESTERDAY...HOWEVER...INDICATE DRIER AIR THROUGH THE
MID/UPPER LEVELS (PWAT VALUES AROUND 1.4") WITH THE BEST SOURCE OF
MOISTURE REMAINING WITHIN THE LOWER 5-10 KFT. AS A RESULT...
CONFIDENCE IN ANY DEEP MOIST CONVECTION OR THUNDERSTORM DEVELOPMENT
IS LOW. HOWEVER...A STORM OR TWO CAN NOT BE COMPLETELY RULED OUT
TODAY AS TEMPERATURES CLIMB BACK INTO THE LOWER 90S AND DEWPOINTS
REMAIN IN THE MID TO UPPER 60S. ON THURSDAY...THE LOW-LEVEL FLOW
WILL BEGIN TO SHIFT TOWARD THE SOUTHEAST...WHICH WILL TRANSLATE TO
THE BEST AFTERNOON SHOWER/TSTM CHANCES OVER THE NORTHWEST INTERIOR
OR FROM NAPLES TO THE LAKE REGION. ELSEWHERE...THE WARM CONDITIONS
WILL PERSIST WITH AFTERNOON HIGHS CLIMBING BACK INTO THE LOWER 80S
NEAR THE EAST COAST TO THE LOWER 90S INLAND. OVERNIGHT LOWS ARE
FORECAST TO RANGE FROM THE UPPER 60S INLAND TO THE LOW TO MID 70S
OVER THE EAST COAST AND METRO AREAS (SEVERAL DEGREES ABOVE THE
NORMAL LOWS) EACH NIGHT. ON FRIDAY...A COLD FRONT ASSOCIATED WITH
THE PREVIOUSLY MENTIONED UPPER TROUGH WILL BEGIN TO APPROACH THE
STATE. MOST OF THE SHOWERS/TSTM COVERAGE...HOWEVER...SHOULD REMAIN
NORTH OF OUR AREA THROUGH THE AFTERNOON PERIOD. PATCHY FOG WILL
REMAIN POSSIBLE EACH NIGHT...MAINLY OVER THE INTERIOR AREAS...WHICH
LINES UP WELL WITH THE LATEST SHORT-RANGE ENSEMBLE GUIDANCE.
LONG TERM (FRIDAY NIGHT-WEDNESDAY)...
THE EXTENDED GUIDANCE REMAINS IN DECENT AGREEMENT AND SHOWS THE
UPPER RIDGE CONTINUING TO SHIFT EAST OVER THE WESTERN ATLANTIC AS A
BROAD UPPER TROUGH SHIFTS EAST OVER THE REGION. A COLD FRONT
ASSOCIATED WITH THIS UPPER FEATURE IS FORECAST TO APPROACH AND BEGIN
TO IMPACT THE STATE OVER THE WEEKEND. INCREASING DEEP LAYER MOISTURE
COMBINED WITH THE APPROACHING FRONT/UPPER TROUGH WILL TRANSLATE TO
INCREASING RAINFALL CHANCES THROUGH THIS TIME. DEEP LAYER SOUTHWEST
FLOW WILL FAVOR ENHANCED ACTIVITY OVER THE EAST COAST
AREAS...ESPECIALLY FROM BROWARD COUNTY TO THE LAKE REGION. AS THE
FORECAST CONFIDENCE CONTINUES TO INCREASE THROUGH THE MID-WEEK
PERIOD...WE WILL BEGIN TO REFLECT THIS WITH INCREASING RAINFALL
CHANCES...ESPECIALLY FOR SATURDAY AND SUNDAY. CONFIDENCE BEYOND THIS
PERIOD INTO THE UPCOMING WEEK BEGINS TO DECREASE DUE TO SOME MODEL
DIFFERENCES. TEMPERATURES ARE FORECAST TO REMAIN AROUND OR SLIGHTLY
ABOVE NORMAL THROUGH THE PERIOD.
MARINE...
LIGHT TO MODERATE EASTERLY WINDS WILL BEGIN TO SHIFT TO THE
SOUTHEAST THURSDAY THROUGH FRIDAY AHEAD OF AN APPROACHING FRONTAL
BOUNDARY. THE COLD FRONT WILL LEAD TO INCREASING RAINFALL CHANCES
FRIDAY THROUGH THE UPCOMING WEEKEND AS THE BOUNDARY STALLS NEAR OR
OVER THE AREA. WINDS WILL SHIFT BACK TO THE EAST LATER IN THE
WEEKEND AND INTO THE UPCOMING WEEK AS THE FRONT WEAKENS AND HIGH
PRESSURE BUILDS BACK OVER THE REGION.
FIRE WEATHER...
PLENTY OF MOISTURE WITH DEWPOINTS REMAINING IN THE MID 60S WILL
KEEP RELATIVE HUMIDITIES WELL ABOVE CRITICAL LEVELS THROUGH THE
AFTERNOON PERIODS. LOW-LEVEL FLOW WILL REMAIN OUT OF THE EAST AND
SOUTHEAST WITH THE BEST CHANCE FOR AFTERNOON SHOWERS AND POSSIBLY
A STORM OR TWO REMAINING OVER THE INTERIOR LOCATIONS TOWARD THE
GULF COAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 73 83 74 / 10 - 10 10
FORT LAUDERDALE 82 76 84 77 / 10 - 10 20
MIAMI 84 73 85 75 / 20 - 10 10
NAPLES 88 69 88 70 / 10 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...57/DG
AREA FORECAST DISCUSSION
NWS GOODLAND KS
521 PM MDT THU APR 18 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 218 PM MDT THU APR 18 2013
EARLY AFTERNOON WV IMAGERY AND RUC H5 ANALYSIS SHOWS POSITIVELY
TILTED TROUGH EXTENDING FROM THE NORTHERN PLAINS ALONG KS/CO BORDER.
AT THE SURFACE HIGH PRESSURE IS IN PLACE OVER EASTERN
COLORADO...WITH A 996MB SURFACE LOW CENTERED OVER THE NORTHERN
MISSISSIPPI VALLEY. NORTHWEST GRADIENT IS IN PLACE AT THE SURFACE
ACROSS OUR CWA...WITH WINDS GUSTING TO 40 MPH.
SEVERAL LOCATIONS INCLUDING KGLD AND KITR HAVE REPORTED SUSTAINED
WINDS WITHIN ADVISORY CRITERIA THIS AFTERNOON. THESE WINDS HAVE BEEN
SHORT LIVED AT THESE LOCATIONS WITH THE OVERALL TREND ACROSS THE
AREA TO REMAIN BELOW ADVISORY CRITERIA...SO NO HIGHLIGHT PLANNED AT
THIS POINT. THERE WAS SOME CONCERN THAT THERE WOULD BE PATCHY
BLOWING SNOW WITH THESE WINDS...AND TO THIS POINT NO REPORTS OF
REDUCED VISIBILITIES HAVE BEEN REPORTED SO FAR THIS AFTERNOON. WITH
FRESHLY FALLEN SNOW AND GUSTS TO 40 MPH I STILL COULDNT RULE THIS
OUT THIS AFTERNOON ESPECIALLY ACROSS OPEN AREAS IN THE COUNTRY SO I
PLAN ON LEAVING PATCHY BLOWING SNOW MENTION IN PLACE THROUGH THE
AFTERNOON HOURS.
OTHER IMMEDIATE FORECAST CONCERN THIS AFTERNOON IS POTENTIAL FOR
FLURRIES (OR SPRINKLES WHERE SURFACE TEMPS ARE ABOVE FREEZING).
RADAR CONTINUES TO SHOW LIGHT RETURNS ACROSS OUR FORECAST
AREA...ASSOCIATED WITH BANDS OF STRATOCUMULUS THAT HAS DEVELOPED
WITH COLD POOL ON BACK SIDE OF UPPER LOW. THERE HAVE BEEN NO RECENT
REPORTS OF PRECIP...HOWEVER I COULDNT RULE OUT NON MEASURABLE
BEFORE SUNSET.
TONIGHT-FRIDAY...WINDS SHOULD DIMINISH AFTER SUNSET AND WITH
UNSEASONABLY COOL AIR MASS IN PLACE AND CLEARING SKIES WE COULD END
UP WITH NEAR RECORD LOW TEMPS AT A FEW LOCATIONS (ESPECIALLY IF
WINDS GO CALM). WINDS SHOULD STILL BE IN THE 10-15 MPH RANGE WHICH
SHOULD LIMIT COOLING. I KEPT FORECAST IN THE UPPER TEENS-LOW 20S FOR
MOST OF THE AREA...WHICH IS ABOVE PREVIOUS DAILY RECORDS. DRY
CONDITIONS AND MILD TEMPS ARE EXPECTED THROUGH THE DAY THU WITH W/NW
FLOW ALOFT AND LEE TROUGH REBUILDING. MODEL SOUNDINGS ARE DRY
ADIABATIC TO ABOUT 700MB AND IF IT WASNT FOR RECENT SNOWFALL I MIGHT
BE CONCERNED WITH POTENTIAL RFW CONDITIONS FRI AFTERNOON.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 218 PM MDT THU APR 18 2013
FORECAST PROBLEMS WILL BE HOW MUCH IT WARMS UP THROUGH THE WEEKEND
BEFORE THE NEXT COLD FRONT MOVES THROUGH AND THE PRECIPITATION
CHANCES THIS WEEKEND AND CONTINUING INTO THE BEGINNING OF NEXT WEEK.
SATELLITE SHOWING THE LARGE SCALE FLOW PATTERN BEING AMPLIFIED AND
BLOCKY FROM THE PACIFIC INTO THE EASTERN NORTH AMERICA. SYSTEM THAT
HAS BROUGHT 2 TO 5 INCHES OF SNOW AND A LOT OF WIND TO THE AREA IS
CONTINUING TO MOVE TOWARD THE EAST. COLD AIR MASS HAS SETTLED OVER
THE REGION.
MODELS APPEAR TO START OUT FINE ON THE UPPER JET. WITH OUR EXITING
SYSTEM AND OVERALL MID LEVELS...THE UKMET WAS DOING A LITTLE BETTER
THAN THE ECMWF AND THE CANADIAN. NAM/ECMWF WERE DOING THE BEST ON
THE SURFACE PRESSURE/WIND FIELD. THE NAM WAS DOING SLIGHTLY BETTER
THAN THE GFS AND SREF ON THE LOW LEVEL THERMAL FIELD.
FRIDAY NIGHT...LEFT FRONT QUADRANT OF THE JET IS NOW MUCH FURTHER
SOUTHWEST OF THE AREA THAT WHAT THE MODELS WERE SHOWING 24 HOURS
AGO. ALSO MID LEVEL LIFT IS BETTER ON EITHER SIDE...ESPECIALLY TO
THE SOUTH. SO WILL KEEP THIS PERIOD DRY. WINDS WILL BECOME LIGHT AND
VARIABLE. AT THE SAME TIME...MID AND HIGH LEVEL CLOUD COVER BECOME
RATHER THICK. SO EXPECT THE CLOUD COVER TO KEEP THE TEMPERATURES FROM
DROPPING TOO MUCH.
SATURDAY/SATURDAY NIGHT...MAIN JET IS STILL FAR TO THE SOUTHWEST OF
THE AREA. MIXED SIGNALS ON CHANCE OF PRECIPITATION. MOISTURE REMAINS
ABOVE 700 MB WITH ONLY WEAK MID LEVEL LIFT IN PLACE. THETA-E LAPSE
RATES ARE GOOD WITH LITTLE TO NO SURFACE/ELEVATED CAPE IN PLACE.
MODELS HAVE LIGHT QPF SCATTERED ALL OVER THE PLACE. FEELING IS THAT
NOT MUCH IS GOING TO REACH THE GROUND. SO REMOVED POPS AND REPLACED
THE AFTERNOON/EVENING WEATHER GRIDS WITH SPRINKLES.
SNOW IS EXPECTED TO MELT PRETTY QUICK SO DO NOT THINK THERE WILL BE
MUCH IF ANY AFFECT ON THE TEMPERATURES. MODELS ARE ALL OVER THE PLACE
WITH THE WIND FIELD. CONSIDERING THE NUMEROUS SHORTWAVE TROUGHS
EMBEDDED WITHIN THE FAST WESTERLY FLOW ALOFT...CAN UNDERSTAND THE
MODEL DIFFICULTIES. OVERALL CONSENSUS WITH THE LIGHT FIELD IS TO HAVE
WINDS FROM AN UPSLOPE DIRECTION. SO THE WINDS WILL NOT HELP WITH THE
WARMUP. AND CONSIDERING THE RATHER THICK CLOUD COVER...AM NOT SOLD ON
A BIG WARM UP. HOWEVER...MODELS HAVE BEEN UNDERDOING WARMUPS RECENTLY
AND CONSIDERING POSSIBLE SNOW FIELD CONTAMINATION...THAT COULD BE THE
CASE HERE. RIGHT NOW WILL GO NEAR THE WARMEST GUIDANCE.
SAME THING WITH THE WIND FIELD FOR THE NIGHT PERIOD WITH WINDS
RATHER LIGHT AND VARIABLE. WILL HAVE DECENT MID/UPPER LEVEL CLOUD
COVER UNTIL LATE IN THE NIGHT. IT LOOKS LIKE THE MINS WILL BE
WARMER DUE TO THE CLOUDS BUT CAN SEE WHERE MINS COULD REALLY DROP
OFF.
SUNDAY...WITH THE EXCEPTION OF THE NAM...MODELS ARE IN AGREEMENT IN
HAVING THE LEFT FRONT QUADRANT OF A STRONG UPPER JET AFFECTING THE
WEST/SOUTHWEST PORTION OF THE AREA IN THE AFTERNOON. THE MODELS HAVE
LESS MOISTURE AROUND THAN THE PREVIOUS DAY. BUT CANNOT IGNORE THIS
INCOMING JET. SOME OF THE MODEL OUTPUT IS PRODUCING LIGHT QPF. SO
AT THIS TIME HAVE PUT IN A SLIGHT CHANCE IN THE AFTERNOON. THIS
TRANSITIONS WELL INTO WHAT THE INIT HAS GIVEN ME FOR SUNDAY NIGHT.
MODEL WIND FIELDS CONTINUE TO BE IN CHAOS AND DISAGREEMENT...WHICH
PROBABLY MEANS LIGHT AND VARIABLE. THIS WIND DISAGREEMENT TRANSLATES
INTO LOW LEVEL THERMAL DISAGREEMENT. THERE LOOKS LIKE THERE WILL BE
MORE SUN THAN THE PREVIOUS FEW DAYS PLUS WINDS MAY END UP DOWNSLOPE.
SO RAISED MAXES SOME.
SUNDAY NIGHT THROUGH THURSDAY...LEFT FRONT QUADRANT/JET AXIS OF THE
ABOVE MENTIONED JET CONTINUES TO STRONGLY AFFECT THE AREA FROM
SUNDAY NIGHT THROUGH MONDAY NIGHT INTO EARLY TUESDAY MORNING. MODELS
ARE IN A LITTLE CLOSER AGREEMENT THAN YESTERDAY. THE ECMWF WHICH
HAS BEEN THE MOST CONSISTENT...HAS SLOWED DOWN/IS FURTHER NORTH WITH
INCOMING UPPER TROUGH. THE ECMWF IS ALSO SLOWER THAN THE REMAINING
MODEL OUTPUT.
SO LIKED AND ACCEPTED WHAT THE CRH INIT GAVE ME FOR POPS THROUGH
TUESDAY WHICH WAS NOT TOO DIFFERENT THAN WHAT THE INIT HAS BEEN
PRODUCING THE LAST COUPLE OF DAYS. SO THAT MEANS A CONTINUED GOOD
CHANCE OF PRECIPITATION FROM SUNDAY NIGHT AND ESPECIALLY MONDAY INTO
MONDAY NIGHT. PRECIPITATION ENDS TUESDAY WITH A DRY FORECAST FOR
TUESDAY NIGHT INTO WEDNESDAY. FOR THURSDAY MODELS AGREE WITH HAVING
NORTHWEST FLOW ALOFT OVER THE AREA WITH EMBEDDED SHORTWAVE TROUGH(S)
IN THIS FLOW...ALWAYS A DANGEROUS SCENARIO AND NEVER CAN RULE OUT ANY
PRECIPITATION. SO THE SLIGHT CHANCE THE INIT GAVE ME LOOKS
REASONABLE.
THANKS TO ALL FOR THE COLLABORATION WHO CHOSE TO COLLABORATE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 520 PM MDT THU APR 18 2013
SURFACE HIGH PRESSURE AND SUBSIDENCE WILL PRODUCE CLEARING ACROSS
THE REGION TONIGHT THROUGH FRIDAY MORNING. SOME SCATTERED CLOUDS
WILL DEVELOP FRIDAY AROUND MIDDAY WITH WIND BECOMING BREEEZY.
&&
.CLIMATE...
ISSUED AT 315 AM MDT THU APR 18 2013
RECORD LOW TEMPERATURES FRIDAY MORNING:
GOODLAND.....18 DEGREES (1953)
HILL CITY....23 DEGREES (1953)
MCCOOK.......22 DEGREES (1953)
BURLINGTON...17 DEGREES (1966)
COLBY........19 DEGREES
TRIBUNE......19 DEGREES
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...FS
CLIMATE...DDT
AREA FORECAST DISCUSSION
NWS GOODLAND KS
218 PM MDT THU APR 18 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 218 PM MDT THU APR 18 2013
EARLY AFTERNOON WV IMAGERY AND RUC H5 ANALYSIS SHOWS POSITIVELY
TILTED TROUGH EXTENDING FROM THE NORTHERN PLAINS ALONG KS/CO BORDER.
AT THE SURFACE HIGH PRESSURE IS IN PLACE OVER EASTERN
COLORADO...WITH A 996MB SURFACE LOW CENTERED OVER THE NORTHERN
MISSISSIPPI VALLEY. NORTHWEST GRADIENT IS IN PLACE AT THE SURFACE
ACROSS OUR CWA...WITH WINDS GUSTING TO 40 MPH.
SEVERAL LOCATIONS INCLUDING KGLD AND KITR HAVE REPORTED SUSTAINED
WINDS WITHIN ADVISORY CRITERIA THIS AFTERNOON. THESE WINDS HAVE BEEN
SHORT LIVED AT THESE LOCATIONS WITH THE OVERALL TREND ACROSS THE
AREA TO REMAIN BELOW ADVISORY CRITERIA...SO NO HIGHLIGHT PLANNED AT
THIS POINT. THERE WAS SOME CONCERN THAT THERE WOULD BE PATCHY
BLOWING SNOW WITH THESE WINDS...AND TO THIS POINT NO REPORTS OF
REDUCED VISIBILITIES HAVE BEEN REPORTED SO FAR THIS AFTERNOON. WITH
FRESHLY FALLEN SNOW AND GUSTS TO 40 MPH I STILL COULDNT RULE THIS
OUT THIS AFTERNOON ESPECIALLY ACROSS OPEN AREAS IN THE COUNTRY SO I
PLAN ON LEAVING PATCHY BLOWING SNOW MENTION IN PLACE THROUGH THE
AFTERNOON HOURS.
OTHER IMMEDIATE FORECAST CONCERN THIS AFTERNOON IS POTENTIAL FOR
FLURRIES (OR SPRINKLES WHERE SURFACE TEMPS ARE ABOVE FREEZING).
RADAR CONTINUES TO SHOW LIGHT RETURNS ACROSS OUR FORECAST
AREA...ASSOCIATED WITH BANDS OF STRATOCUMULUS THAT HAS DEVELOPED
WITH COLD POOL ON BACK SIDE OF UPPER LOW. THERE HAVE BEEN NO RECENT
REPORTS OF PRECIP...HOWEVER I COULDNT RULE OUT NON MEASURABLE
BEFORE SUNSET.
TONIGHT-FRIDAY...WINDS SHOULD DIMINISH AFTER SUNSET AND WITH
UNSEASONABLY COOL AIR MASS IN PLACE AND CLEARING SKIES WE COULD END
UP WITH NEAR RECORD LOW TEMPS AT A FEW LOCATIONS (ESPECIALLY IF
WINDS GO CALM). WINDS SHOULD STILL BE IN THE 10-15 MPH RANGE WHICH
SHOULD LIMIT COOLING. I KEPT FORECAST IN THE UPPER TEENS-LOW 20S FOR
MOST OF THE AREA...WHICH IS ABOVE PREVIOUS DAILY RECORDS. DRY
CONDITIONS AND MILD TEMPS ARE EXPECTED THROUGH THE DAY THU WITH W/NW
FLOW ALOFT AND LEE TROUGH REBUILDING. MODEL SOUNDINGS ARE DRY
ADIABATIC TO ABOUT 700MB AND IF IT WASNT FOR RECENT SNOWFALL I MIGHT
BE CONCERNED WITH POTENTIAL RFW CONDITIONS FRI AFTERNOON.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 218 PM MDT THU APR 18 2013
FORECAST PROBLEMS WILL BE HOW MUCH IT WARMS UP THROUGH THE WEEKEND
BEFORE THE NEXT COLD FRONT MOVES THROUGH AND THE PRECIPITATION
CHANCES THIS WEEKEND AND CONTINUING INTO THE BEGINNING OF NEXT WEEK.
SATELLITE SHOWING THE LARGE SCALE FLOW PATTERN BEING AMPLIFIED AND
BLOCKY FROM THE PACIFIC INTO THE EASTERN NORTH AMERICA. SYSTEM THAT
HAS BROUGHT 2 TO 5 INCHES OF SNOW AND A LOT OF WIND TO THE AREA IS
CONTINUING TO MOVE TOWARD THE EAST. COLD AIR MASS HAS SETTLED OVER
THE REGION.
MODELS APPEAR TO START OUT FINE ON THE UPPER JET. WITH OUR EXITING
SYSTEM AND OVERALL MID LEVELS...THE UKMET WAS DOING A LITTLE BETTER
THAN THE ECMWF AND THE CANADIAN. NAM/ECMWF WERE DOING THE BEST ON
THE SURFACE PRESSURE/WIND FIELD. THE NAM WAS DOING SLIGHTLY BETTER
THAN THE GFS AND SREF ON THE LOW LEVEL THERMAL FIELD.
FRIDAY NIGHT...LEFT FRONT QUADRANT OF THE JET IS NOW MUCH FURTHER
SOUTHWEST OF THE AREA THAT WHAT THE MODELS WERE SHOWING 24 HOURS
AGO. ALSO MID LEVEL LIFT IS BETTER ON EITHER SIDE...ESPECIALLY TO
THE SOUTH. SO WILL KEEP THIS PERIOD DRY. WINDS WILL BECOME LIGHT AND
VARIABLE. AT THE SAME TIME...MID AND HIGH LEVEL CLOUD COVER BECOME
RATHER THICK. SO EXPECT THE CLOUD COVER TO KEEP THE TEMPERATURES FROM
DROPPING TOO MUCH.
SATURDAY/SATURDAY NIGHT...MAIN JET IS STILL FAR TO THE SOUTHWEST OF
THE AREA. MIXED SIGNALS ON CHANCE OF PRECIPITATION. MOISTURE REMAINS
ABOVE 700 MB WITH ONLY WEAK MID LEVEL LIFT IN PLACE. THETA-E LAPSE
RATES ARE GOOD WITH LITTLE TO NO SURFACE/ELEVATED CAPE IN PLACE.
MODELS HAVE LIGHT QPF SCATTERED ALL OVER THE PLACE. FEELING IS THAT
NOT MUCH IS GOING TO REACH THE GROUND. SO REMOVED POPS AND REPLACED
THE AFTERNOON/EVENING WEATHER GRIDS WITH SPRINKLES.
SNOW IS EXPECTED TO MELT PRETTY QUICK SO DO NOT THINK THERE WILL BE
MUCH IF ANY AFFECT ON THE TEMPERATURES. MODELS ARE ALL OVER THE PLACE
WITH THE WIND FIELD. CONSIDERING THE NUMEROUS SHORTWAVE TROUGHS
EMBEDDED WITHIN THE FAST WESTERLY FLOW ALOFT...CAN UNDERSTAND THE
MODEL DIFFICULTIES. OVERALL CONSENSUS WITH THE LIGHT FIELD IS TO HAVE
WINDS FROM AN UPSLOPE DIRECTION. SO THE WINDS WILL NOT HELP WITH THE
WARMUP. AND CONSIDERING THE RATHER THICK CLOUD COVER...AM NOT SOLD ON
A BIG WARM UP. HOWEVER...MODELS HAVE BEEN UNDERDOING WARMUPS RECENTLY
AND CONSIDERING POSSIBLE SNOW FIELD CONTAMINATION...THAT COULD BE THE
CASE HERE. RIGHT NOW WILL GO NEAR THE WARMEST GUIDANCE.
SAME THING WITH THE WIND FIELD FOR THE NIGHT PERIOD WITH WINDS
RATHER LIGHT AND VARIABLE. WILL HAVE DECENT MID/UPPER LEVEL CLOUD
COVER UNTIL LATE IN THE NIGHT. IT LOOKS LIKE THE MINS WILL BE
WARMER DUE TO THE CLOUDS BUT CAN SEE WHERE MINS COULD REALLY DROP
OFF.
SUNDAY...WITH THE EXCEPTION OF THE NAM...MODELS ARE IN AGREEMENT IN
HAVING THE LEFT FRONT QUADRANT OF A STRONG UPPER JET AFFECTING THE
WEST/SOUTHWEST PORTION OF THE AREA IN THE AFTERNOON. THE MODELS HAVE
LESS MOISTURE AROUND THAN THE PREVIOUS DAY. BUT CANNOT IGNORE THIS
INCOMING JET. SOME OF THE MODEL OUTPUT IS PRODUCING LIGHT QPF. SO
AT THIS TIME HAVE PUT IN A SLIGHT CHANCE IN THE AFTERNOON. THIS
TRANSITIONS WELL INTO WHAT THE INIT HAS GIVEN ME FOR SUNDAY NIGHT.
MODEL WIND FIELDS CONTINUE TO BE IN CHAOS AND DISAGREEMENT...WHICH
PROBABLY MEANS LIGHT AND VARIABLE. THIS WIND DISAGREEMENT TRANSLATES
INTO LOW LEVEL THERMAL DISAGREEMENT. THERE LOOKS LIKE THERE WILL BE
MORE SUN THAN THE PREVIOUS FEW DAYS PLUS WINDS MAY END UP DOWNSLOPE.
SO RAISED MAXES SOME.
SUNDAY NIGHT THROUGH THURSDAY...LEFT FRONT QUADRANT/JET AXIS OF THE
ABOVE MENTIONED JET CONTINUES TO STRONGLY AFFECT THE AREA FROM
SUNDAY NIGHT THROUGH MONDAY NIGHT INTO EARLY TUESDAY MORNING. MODELS
ARE IN A LITTLE CLOSER AGREEMENT THAN YESTERDAY. THE ECMWF WHICH
HAS BEEN THE MOST CONSISTENT...HAS SLOWED DOWN/IS FURTHER NORTH WITH
INCOMING UPPER TROUGH. THE ECMWF IS ALSO SLOWER THAN THE REMAINING
MODEL OUTPUT.
SO LIKED AND ACCEPTED WHAT THE CRH INIT GAVE ME FOR POPS THROUGH
TUESDAY WHICH WAS NOT TOO DIFFERENT THAN WHAT THE INIT HAS BEEN
PRODUCING THE LAST COUPLE OF DAYS. SO THAT MEANS A CONTINUED GOOD
CHANCE OF PRECIPITATION FROM SUNDAY NIGHT AND ESPECIALLY MONDAY INTO
MONDAY NIGHT. PRECIPITATION ENDS TUESDAY WITH A DRY FORECAST FOR
TUESDAY NIGHT INTO WEDNESDAY. FOR THURSDAY MODELS AGREE WITH HAVING
NORTHWEST FLOW ALOFT OVER THE AREA WITH EMBEDDED SHORTWAVE TROUGH(S)
IN THIS FLOW...ALWAYS A DANGEROUS SCENARIO AND NEVER CAN RULE OUT ANY
PRECIPITATION. SO THE SLIGHT CHANCE THE INIT GAVE ME LOOKS
REASONABLE.
THANKS TO ALL FOR THE COLLABORATION WHO CHOSE TO COLLABORATE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1123 AM MDT THU APR 18 2013
MVFR CIGS AND SCATTERED FLURRIES WILL CONTINUE THROUGH THE
AFTERNOON AS UPPER LEVEL SYSTEM SHIFTS EAST OF THE AREA.
CONDITIONS SHOULD IMPROVE AT KGLD BY MID AFTERNOON...AND BY THIS
EVENING AT KCMK. COULDNT RULE OUT EARLIER IMPROVEMENT...OR AT
LEAST AN END TO PREVAILING MVFR CIGS...HOWEVER WILL HAVE TO
MONITOR. GUSTY NORTHWEST WINDS WILL CONTINUE THROUGH THE EVENING
HOURS WITH AFTERNOON GUSTS AROUND 30-35KT AT BOTH TERMINALS. WINDS
TONIGHT WILL SHIFT TO THE WEST TONIGHT IN THE 10-13KT RANGE...WITH
GUST WINDS DEVELOPING AFTER SUNRISE.
&&
.CLIMATE...
ISSUED AT 315 AM MDT THU APR 18 2013
RECORD LOW TEMPERATURES FRIDAY MORNING:
GOODLAND.....18 DEGREES (1953)
HILL CITY....23 DEGREES (1953)
MCCOOK.......22 DEGREES (1953)
BURLINGTON...17 DEGREES (1966)
COLBY........19 DEGREES
TRIBUNE......19 DEGREES
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...DR
CLIMATE...DDT
AREA FORECAST DISCUSSION
NWS GOODLAND KS
316 PM MDT WED APR 17 2013
.SHORT TERM...(THIS AFTERNOON THROUGH THURSDAY)
ISSUED AT 132 PM MDT WED APR 17 2013
EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOWS POSITIVELY
TITLED LONGWAVE TROUGH EXTENDING SOUTH ALONG CENTRAL ROCKIES WITH
DRY SLOT/AREA OF SUBSIDENCE IN PLACE AHEAD OF THIS OVER WESTERN
KANSAS AND CENTRAL NEBRASKA. LOW AT THE SURFACE A STALLED FRONT
EXTENDS FROM THE TEXAS PANHANDLE ACROSS CENTRAL OKLAHOMA TO
SOUTHEAST KANSAS. NORTHWEST FLOW IS IN PLACE ACROSS OUR CWA WITH
VERY MOIST BL CONDITIONS PERSISTING...WHICH HAS RESULTED IN AREAS
OF FOG AND DRIZZLE PERSISTING THROUGH THE AFTERNOON HOURS. WITH
TEMPERATURES NEAR OR BELOW FREEZING...WE COULD CONTINUE TO SEE
LIGHT ICE ACCUMULATIONS ON ELEVATED SURFACES BEFORE SNOW DEVELOPS
LATER.
THE PRIMARY FORECAST FOCUS IS ON DEVELOPING WINTER STORM FOR
LATE THIS AFTERNOON THROUGH EARLY THURSDAY MORNING.
UPPER LEVEL TROUGH IS PROGGED TO SHIFT EAST THIS EVENING...WITH
LARGE SCALE ASCENT AND MID LEVEL MOISTURE OVERSPREADING THE CWA.
BROAD AXIS OF MID LEVEL FRONTOGENESIS IS EXPECTED TO SET UP ACROSS
THE NORTHWEST HALF OF OUR CWA THIS EVENING. LIGHT SNOW AND
BANDS OF MODERATE SNOW TRAINING FROM THE SOUTH TO THE NORTH. WITH
SURFACE TEMPS ALREADY BELOW FREEZING THIS AFTERNOON IN THE
NORTHWEST AND A SECOND COLD SURGE EXPECTED LATE THIS
AFTERNOON/EARLY THIS EVENING...I THINK WE SHOULD SEE A FAST
RAIN/SNOW CHANGEOVER WITH ALL SNOW IN OUR CWA THIS EVENING AND
TONIGHT. THERE IS QUITE A BIT OF SPREAD REGARDING QPF
VALUES...WITH GFS THE HIGH OUTLIER. WITH SREF (TRADITIONALLY HIGH)
AND OTHER GUIDANCE MORE IN LINE WITH PREVIOUS FORECAST QPF/SNOW
TOTALS I DISCOUNTED THE GFS SOLUTION AND ONLY MADE MINOR CHANGES
TO AMOUNTS. WE ARE CURRENTLY FORECAST 3-5 INCHES FOR MOST OF THE
AREA...WITH HIGHS AMOUNTS MORE LIKELY NORTH OF INTERSTATE 70.
OTHER CONCERN (AND POSSIBLY THE HIGHER IMPACT) IS STRONG WINDS
PROGGED TO DEVELOP THIS EVENING. ALL GUIDANCE IS SUPPORTIVE OF
GUSTY WINDS...HOWEVER GFS/MAV CONTINUES TO BE THE HIGH OUTLIER
WITH GUSTS IN EXCESS OF 60 MPH. NAM/SREF/ECMWF ALL ARE LOWER...AND
WITH BEST PRESSURE RISES ADVERTISED TO BE FURTHER SOUTH...THESE
SOLUTIONS MAY BE MORE REASONABLE. I USED A BLEND THAT FAVORED THE
NAM MIXED LAYER WINDS AND NUDGED A LITTLE TOWARDS GFS/MAV WHICH
RESULTS IN GUSTS THIS EVENING TO 50 MPH. EVEN WITH THE LOWER END
OF GUIDANCE WE SHOULD SEE BLOWING SNOW WITH REDUCED VISIBILITIES. THE
SPREAD IN GUIDANCE AND POSSIBLE LIMITED DURATION OF THE STRONGEST
WINDS IN OUR AREA RAISES QUESTIONS TO HOW LOW THESE VISIBILITIES WILL
BE AND HOW LONG. I FELT THE WINTER WEATHER ADVISORY WAS APPROPRIATE
WITH BRIEF BLIZZARD CONDITIONS POSSIBLE. IF WINDS END UP BEING MORE
IN LINE WITH GFS SOLUTION WE MAY NEED TO CONVERT WESTERN LOCATIONS TO
A BLIZZARD WARNING...CONFIDENCE JUST ISNT THERE RIGHT NOW.
THE WORST CONDITIONS SHOULD BE 03Z THROUGH ABOUT 09Z TONIGHT...WITH
SNOW ENDING QUICKLY FROM THE WEST TO THE EAST EARLY THU MORNING.
WE COULD SEE LINGERING SNOW INTO THU IN OUR NORTHEAST...HOWEVER
WITH BEST FORCING/MOISTURE OUTSIDE OUR AREA I AM NOT ANTICIPATING
VERY MUCH ADDITIONAL ACCUMULATION. WE SHOULD SEE ANOTHER BLUSTERY
DAY THURSDAY WITH HIGHS IN THE 30S AND GUSTY WINDS THROUGH THE
DAY. GFS/MAV IS AGAIN MUCH HIGHER ON WINDS THU AND MIGHT SUPPORT
ADVISORY CRITERIA. I WILL HAVE TO SEE WHAT KIND OF BIAS THE GFS
HAD TONIGHT TO HAVE ANY ANY CONFIDENCE IN THE HIGHER WINDS THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 316 PM MDT WED APR 17 2013
FORECAST PROBLEMS WILL BE HOW MUCH IT WARMS UP THROUGH THE WEEKEND
BEFORE THE NEXT COLD FRONT MOVES THROUGH AND THE PRECIPITATION
CHANCES THIS WEEKEND AND CONTINUING INTO THE BEGINNING OF NEXT WEEK.
SATELLITE SHOWING THE LARGE SCALE FLOW PATTERN BEING AMPLIFIED AND
BLOCKY FROM THE PACIFIC INTO THE EASTERN NORTH AMERICA.
THURSDAY NIGHT...SYSTEM THAT WILL HAVE BROUGHT THE AREA SNOW AND
WIND WILL CONTINUE TO MOVE AWAY. MODERATE GRADIENT CONTINUES THROUGH
THE NIGHT AND LOOKS LIKE THE WINDS WILL STAY UP ENOUGH TO KEEP THE
TEMPERATURES FROM BOTTOMING OUT.
FRIDAY/FRIDAY NIGHT...RIGHT REAR QUADRANT OF UPPER JET GOES ACROSS
THE NORTHERN PORTION OF THE AREA DURING THE DAY. AT THIS TIME WITH
A LARGE DRY LAYER IN THE LOW AND MID LEVELS...THIS ONLY LOOKS LIKE
IT WILL SPREAD CLOUDS ACROSS THE AREA. DURING THE NIGHT...THE LEFT
FRONT QUADRANT IS NEAR OR JUST SOUTHWEST OF THE SOUTHWEST PORTION OF
OUR AREA. AS IT LOOKS THE MAIN MID LEVEL LIFT LOOKS TO STAY TO NORTH
AND SOUTH OF THE AREA. ALSO PROBLEM AGAIN LOOKS TO BE A LACK OF
MOISTURE IN THE LOW LEVELS. SO WILL KEEP THIS PERIOD DRY AS WELL.
CLOUDS WILL DECREASE THROUGH THE NIGHT WITH THE MODELS SHOWING A
HIGHLY VARIABLE WIND FIELD AND DISAGREE WITH EACH OTHER. WILL TEND
TOWARD THE COOLER SIDE.
SATURDAY...MAIN JET REMAINS SOUTH AND WEST OF THE AREA. HIGHER LEVEL
CLOUD COVER INCREASES THROUGH THE DAY AS A COUPLE DIFFERENT SHORTWAVE
TROUGHS MOVE THROUGH. THIS MAY HINDER THE TEMPERATURES. HOWEVER...
MODELS HAVE BEEN MISSING THE BOAT ON TEMPERATURES HERE RECENTLY. HAVE
A LIGHT AND VARIABLE WIND FIELD WHICH ALSO DOES NOT BODE WELL FOR
GOING TOO WARM. MODELS HANDLE THIS DIFFERENTLY DUE TO THE DIFFERENT
HANDLING OF THE INCOMING SYSTEM. 700 TO 500 MB PATTERN WOULD
DEFINITELY SUPPORT AN EARLIER SURFACE TROUGH/FRONTAL PASSAGE. MORE
SUPPORT FOR GOING WARMER SO DID NUDGE UP TEMPERATURES A LITTLE BUT
NOT A LOT OF CONFIDENCE IN THIS DUE TO RECENT TEMPERATURE
PERFORMANCE.
NOT A LOT OF SURFACE CONVERGENCE WITH THIS WIND FIELD. PLUS ALL THE
MOISTURE LOOKS TO BE ABOVE 700 MB. SO WILL KEEP THIS PERIOD DRY.
SATURDAY NIGHT THROUGH WEDNESDAY...IN GENERAL THE MODELS ARE
CAPTURING THE OVERALL PATTERN. THE MODELS DROP A SYSTEM INTO THE
NORTH CENTRAL PORTION OF THE COUNTRY SUNDAY INTO MONDAY AND THEN
BRING THE UPPER TROUGH THROUGH AROUND TUESDAY AND THEN EAST OF THE
AREA. HOWEVER...THEY ARE DIFFERING ON THE TIMING OF THE NUMEROUS
SHORTWAVE TROUGHS THAT MOVE THROUGH IN THE WESTERLY FLOW ALOFT PRIOR
TO THE UPPER TROUGH MOVING THROUGH. THEY ALSO DIFFER IN HOW FAR SOUTH
AND HOW FAST THEY TAKE THE UPPER TROUGH THROUGH.
SO IN GENERAL THEY AGREE ON MAKING IT WET BUT NOT THE TIMING. THE
BIGGEST PROBLEM ON TIMING CENTERS AROUND TUESDAY. THE ECMWF TAKES
THE UPPER TROUGH THROUGH SOONER THAN THE GFS AND CANADIAN. SO DID
NOT HAVE ANY PROBLEM WITH WHAT THE CRH INIT GAVE ME WHICH IS
RAMPING UP POPS SUNDAY NIGHT WITH THE HIGHEST POPS MONDAY INTO
MONDAY NIGHT. FOR TUESDAY THE INIT GAVE ME POPS IN THE MIDDLE OF
THE TWO CAMPS AND COULD LIVE WITH THAT. AFTER TUESDAY IT LOOKS DRY.
STRONG COLD FRONT COMES THROUGH LATE SUNDAY NIGHT INTO EARLY MONDAY
MORNING. PER THIS RATHER FAST FRONTAL PASSAGE AND COLLABORATION
CHOSE TO LOWER MONDAY AND TUESDAY MAXES FROM WHAT THE CRH INIT GAVE
ME. OTHERWISE MADE NO OTHER CHANGES
THANKS TO ALL FOR THE COLLABORATION
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1127 AM MDT WED APR 17 2013
THIS AFTERNOON...LOW STRATUS/IFR CIGS WILL PERSIST THROUGH THE
AFTERNOON...WITH LIFR VIS AT KGLD ASSOCIATED WITH DENSE
FOG/FREEZING DRIZZLE. SHORT RANGE GUIDANCE CONTINUES TO INDICATE
VIS IMPROVING EARLY THIS AFTERNOON...HOWEVER WITH NE FLOW AT THE
SURFACE AND MOIST BOUNDARY LAYER I ADJUSTED TAFS TO INDICATE
LINGERING LIFR CONDITIONS AT KGLD THROUGH 21Z WHEN SNOW OVER
EASTERN COLORADO SPREADS EAST AND SHOULD HELP MIX OUT THE LOW
LEVELS.
THIS EVENING-THURSDAY...WINTER STORM STILL EXPECTED TO IMPACT BOTH
TERMINALS STARTING THIS EVENING WITH LOW VIS ASSOCIATED WITH
SNOW/BLOWING SNOW EXPECTED THROUGH EARLY THURSDAY MORNING. LIGHT
SNOW/BLOWING SNOW MAY LINGER LONGER AT KMCK AS UPPER LEVEL SYSTEM
MOVES EAST. OVERALL VIS SHOULD IMPROVE TO VFR AT BOTH TERMINALS BY
SUNRISE...WITH CIGS IMPROVING TO MVFR BY MID MORNING THURSDAY.
&&
.CLIMATE...
ISSUED AT 330 AM MDT WED APR 17 2013
RECORD LOW HIGH TEMPERATURES IN JEOPARDY THURSDAY:
GOODLAND.....38 DEGREES
HILL CITY....47 DEGREES
MCCOOK.......35 DEGREES
BURLINGTON...35 DEGREES
YUMA.........36 DEGREES
COLBY........39 DEGREES
TRIBUNE......40 DEGREES
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WINTER WEATHER ADVISORY FROM 6 PM MDT /7 PM CDT/ THIS EVENING TO
6 AM MDT /7 AM CDT/ THURSDAY FOR KSZ001>004-013>016-027>029-
041-042.
CO...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM MDT
THURSDAY FOR COZ090>092.
NE...WINTER WEATHER ADVISORY FROM 6 PM MDT /7 PM CDT/ THIS EVENING TO
6 AM MDT /7 AM CDT/ THURSDAY FOR NEZ079>081.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...DR
CLIMATE...JTL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
344 PM CDT WED APR 17 2013
...UPDATED SYNOPSIS AND SHORT TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 343 PM CDT WED APR 17 2013
THE 12Z UPPER AIR ANALYSIS SHOWED A DEEP TROUGH EXTENDING FROM THE
NORTHERN ROCKIES INTO THE GREAT BASIN. A 150+ KNOT UPPER LEVEL JET
WAS IN THE BASE OF THE TROUGH OVER SOUTHERN ARIZONA AND NEW MEXICO.
AT THE 850 MB LEVEL...LOW PRESSURE WAS CENTERED OVER NORTHERN NEW
MEXICO. EAST OF THE LOW...A NEARLY STATIONARY FRONTAL BOUNDARY
EXTENDED EAST ACROSS THE NORTHERN TEXAS PANHANDLE INTO SOUTH CENTRAL
AND EASTERN KANSAS. AT THE SURFACE...THE FRONTAL BOUNDARY EXTENDED
FROM EASTERN NEW MEXICO ACROSS WEST TEXAS AND THEN NORTHEAST ACROSS
CENTRAL OKLAHOMA. WARM AND MOIST AIR WAS STREAMING NORTH ACROSS
TEXAS INTO THE CENTRAL PLAINS AND WAS CONTRIBUTING TO A VERY
UNSTABLE AIRMASS ACROSS OKLAHOMA INTO SOUTH CENTRAL AND SOUTHEAST
KANSAS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 343 PM CDT WED APR 17 2013
THERE WILL BE A CONTINUED THREAT FOR SEVERE WEATHER OVER SOUTH
CENTRAL KANSAS THIS EVENING. THE NAM IS INDICATING THAT THE 850 MB
FRONTAL BOUNDARY WILL BE IN THE AREA FROM COLDWATER AND MEDICINE
LODGE TO ST JOHN THIS EVENING BEFORE SHIFTING SOUTH OF THE AREA BY
MIDNIGHT. RAP MODEL SOUNDINGS SHOW AROUND 1500 J/KG OF ELEVATED CAPE
IN THAT AREA. AS THE SOUTHWESTERN U.S. UPPER JET PROPAGATES EASTWARD
INTO THE SOUTHERN PLAINS THIS EVENING...INCREASING UPWARD VERTICAL
MOTION COULD AID IN THE DEVELOPMENT OF ADDITIONAL THUNDERSTORMS.
THERE WILL BE A THREAT FOR HAIL UP TO QUARTER SIZE IN THAT AREA.
THE UPPER TROUGH MOVES EAST OUT OVER THE HIGH PLAINS TONIGHT. MODEL
SOUNDINGS ARE INDICATING SATURATED CONDITIONS GENERALLY BELOW 700 MB
THROUGH THE NIGHT WITH THE LEVELS ABOVE 700 MB SATURATING FOR A 3-6
HOUR TIME FRAME DURING THE NIGHT. LOCATIONS FARTHER WEST ACROSS
WESTERN KANSAS WILL SEE AREAS OF DRIZZLE CONTINUING ALONG WITH A
CHANCE FOR RAIN SHOWERS. THERE WILL BE A TRANSITION FROM RAIN TO
SNOW WITH A PERIOD OF SLEET/FREEZING RAIN POSSIBLE IN BETWEEN. THE
ATMOSPHERE SHOULD COOL OFF ENOUGH FOR SNOW TO DEVELOP OVER WEST
CENTRAL KANSAS DURING THE EVENING HOURS WITH THIS SPREADING INTO
CENTRAL KANSAS AFTER MIDNIGHT. GIVEN THE SHORT WINDOW OF OPPORTUNITY
FOR THE SEEDER/FEEDER MECHANISM TO OCCUR...DO NOT EXPECT SNOW
AMOUNTS TO BE SIGNIFICANT WITH ONLY SOME LIGHT ACCUMULATIONS
POSSIBLE ON GRASSY AREAS. AM NOT ANTICIPATING ANY SIGNIFICANT ICE
ACCUMULATIONS TO OCCUR ALTHOUGH SOME ELEVATED SURFACES COULD GET
SOME LIGHT COATINGS.
AS COLD AIR ADVECTION INCREASES...STRONG NORTHERLY WINDS DEVELOP
OVER THE WESTERN HIGH PLAINS AND SPREAD EASTWARD TONIGHT. LOW LEVEL
WINDS THROUGH THE 850 MB LEVEL INCREASE TO 40-50 KNOTS OVERNIGHT
WHICH SHOULD SUPPORT WIND ADVISORY CRITERIA WINDS LATER TONIGHT INTO
THURSDAY MORNING. HAVE ISSUED A WIND ADVISORY FOR MIDNIGHT TONIGHT
UNTIL NOON THURSDAY FOR ALL OF SOUTHWEST AND CENTRAL KANSAS.
PRECIPITATION SHOULD BE WINDING DOWN FAIRLY QUICKLY LATE TONIGHT AND
THURSDAY MORNING AS THE UPPER SYSTEM MOVES EAST OF THE REGION.
CLOUDS SHOULD BE BREAKING UP FROM WEST TO EAST DURING THE DAY. WITH
SOME SUN...AFTERNOON HIGH TEMPERATURES MAY BE ABLE TO CLIMB INTO THE
LOWER 40S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 338 PM CDT WED APR 17 2013
FRIDAY:
UPPER LEVEL WNW FLOW WILL CONTINUE ON FRIDAY. AT THE SURFACE, HIGH
PRESSURE WILL RIDGE ACROSS THE PLAINS. NORTHWESTERLY WINDS WILL
EVENTUALLY BECOME SOUTHERLY AFTER SUNSET. HIGHS WILL BE IN THE 50S
AND LOWS WILL BE IN THE 20S. NO PRECIPITATION IS EXPECTED AS DRY
FLOW ALOFT AND LACK OF BL MOISTURE CONTINUES.
WEEKEND:
AN UPPER LEVEL TROUGH WILL DIG ACROSS THE CENTRAL AND SOUTHERN
ROCKIES THROUGH THE WEEKEND. THIS WILL PROMOTE A WARM AIR ADVECTION
PATTERN DOWNSTREAM ACROSS OUR REGION. A WARM 850 HPA PLUME WILL
ADVECT OFF THE ROCKIES AND OUT ACROSS SOUTHWEST KANSAS SATURDAY.
THIS WILL FAVOR DEEP MIXING AND HIGHS IN THE UPPER 60S TO LOWER 70S.
OVERNIGHT LOWS WILL MODERATE AS WELL WITH 30S ON SATURDAY AND 40S ON
SUNDAY. TEMPERATURES AROUND 70 DEG F CAN BE EXPECTED SUNDAY AS THE
AFOREMENTIONED WARM PLUME CONTINUES ACROSS THE REGION. THERE COULD BE
A FEW SHOWERS ACROSS SC/S KANSAS IN ASSOCIATION WITH WARM ADVECTION
BUT CONFIDENCE IS LOW AND MODELS ARE FAIRLY LIGHT ON QPF.
NEXT WEEK AND BEYOND:
A MAJOR CHANGE IN WEATHER IS POSSIBLE MONDAY OR TUESDAY. ANOTHER TROF
DIGGING OUT OF THE NORTHERN ROCKIES WILL USHER IN THE PASSAGE OF A
SIGNIFICANT COLD FRONT. THE ECMWF IS FAIRLY COLD WITH 850 HPA
TEMPERATURES DECREASING DOWN TO -6 DEG C. BOTH THE GFS AND ECMWF
INDICATE SOME LIGHT SNOWFALL ACROSS THE REGION ASSOCIATED WITH THIS
FRONT. CONFIDENCE IS LOW FOR PRECIPITATION TYPE BUT THERE IS HIGHER
CONFIDENCE IN LOWER TEMPERATURES WITH 40S AND 50S FOR HIGHS BY
TUESDAY/WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1249 PM CDT WED APR 17 2013
A COOL MOIST UPSLOPE FLOW OVER SOUTHWEST KANSAS WILL KEEP IFR/LIFR
CIGS IN PLACE THROUGH THE REMAINDER OF TODAY INTO TONIGHT. AREAS
OF DRIZZLE WILL CONTINUE TO PREVAIL AT GARDEN CITY AND DODGE
CITY. RAIN SHOWERS WILL BE IN THE VICINITY OF HAYS THROUGH PARTS OF
THE AFTERNOON. COLDER AIR WILL MOVE INTO WESTERN KANSAS THIS
EVENING AND WILL RESULT IN AREAS OF SLEET AND SNOW DEVELOPING
BETWEEN 03Z AND 06Z. CONDITIONS SHOULD BE IMPROVING AROUND 10-12Z
WITH CIGS AND VSBYS IMPROVING INTO THE MVFR/VFR CATEGORY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 27 40 24 59 / 50 10 0 0
GCK 25 40 22 60 / 60 20 0 0
EHA 25 42 23 60 / 50 10 0 0
LBL 26 43 23 60 / 50 10 0 0
HYS 27 39 23 58 / 60 30 0 0
P28 32 44 28 60 / 60 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM MIDNIGHT CDT /11 PM MDT/ TONIGHT TO NOON CDT
/11 AM MDT/ THURSDAY FOR KSZ030-031-043>046-061>066-074>081-
084>090.
&&
$$
SYNOPSIS...GERARD
SHORT TERM...GERARD
LONG TERM...SUGDEN
AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS GOODLAND KS
132 PM MDT WED APR 17 2013
.SHORT TERM...(THIS AFTERNOON THROUGH THURSDAY)
ISSUED AT 132 PM MDT WED APR 17 2013
EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOWS POSITIVELY
TITLED LONGWAVE TROUGH EXTENDING SOUTH ALONG CENTRAL ROCKIES WITH
DRY SLOT/AREA OF SUBSIDENCE IN PLACE AHEAD OF THIS OVER WESTERN
KANSAS AND CENTRAL NEBRASKA. LOW AT THE SURFACE A STALLED FRONT
EXTENDS FROM THE TEXAS PANHANDLE ACROSS CENTRAL OKLAHOMA TO
SOUTHEAST KANSAS. NORTHWEST FLOW IS IN PLACE ACROSS OUR CWA WITH
VERY MOIST BL CONDITIONS PERSISTING...WHICH HAS RESULTED IN AREAS
OF FOG AND DRIZZLE PERSISTING THROUGH THE AFTERNOON HOURS. WITH
TEMPERATURES NEAR OR BELOW FREEZING...WE COULD CONTINUE TO SEE
LIGHT ICE ACCUMULATIONS ON ELEVATED SURFACES BEFORE SNOW DEVELOPS
LATER.
THE PRIMARY FORECAST FOCUS IS ON DEVELOPING WINTER STORM FOR
LATE THIS AFTERNOON THROUGH EARLY THURSDAY MORNING.
UPPER LEVEL TROUGH IS PROGGED TO SHIFT EAST THIS EVENING...WITH
LARGE SCALE ASCENT AND MID LEVEL MOISTURE OVERSPREADING THE CWA.
BROAD AXIS OF MID LEVEL FRONTOGENESIS IS EXPECTED TO SET UP ACROSS
THE NORTHWEST HALF OF OUR CWA THIS EVENING. LIGHT SNOW AND
BANDS OF MODERATE SNOW TRAINING FROM THE SOUTH TO THE NORTH. WITH
SURFACE TEMPS ALREADY BELOW FREEZING THIS AFTERNOON IN THE
NORTHWEST AND A SECOND COLD SURGE EXPECTED LATE THIS
AFTERNOON/EARLY THIS EVENING...I THINK WE SHOULD SEE A FAST
RAIN/SNOW CHANGEOVER WITH ALL SNOW IN OUR CWA THIS EVENING AND
TONIGHT. THERE IS QUITE A BIT OF SPREAD REGARDING QPF
VALUES...WITH GFS THE HIGH OUTLIER. WITH SREF (TRADITIONALLY HIGH)
AND OTHER GUIDANCE MORE IN LINE WITH PREVIOUS FORECAST QPF/SNOW
TOTALS I DISCOUNTED THE GFS SOLUTION AND ONLY MADE MINOR CHANGES
TO AMOUNTS. WE ARE CURRENTLY FORECAST 3-5 INCHES FOR MOST OF THE
AREA...WITH HIGHS AMOUNTS MORE LIKELY NORTH OF INTERSTATE 70.
OTHER CONCERN (AND POSSIBLY THE HIGHER IMPACT) IS STRONG WINDS
PROGGED TO DEVELOP THIS EVENING. ALL GUIDANCE IS SUPPORTIVE OF
GUSTY WINDS...HOWEVER GFS/MAV CONTINUES TO BE THE HIGH OUTLIER
WITH GUSTS IN EXCESS OF 60 MPH. NAM/SREF/ECMWF ALL ARE LOWER...AND
WITH BEST PRESSURE RISES ADVERTISED TO BE FURTHER SOUTH...THESE
SOLUTIONS MAY BE MORE REASONABLE. I USED A BLEND THAT FAVORED THE
NAM MIXED LAYER WINDS AND NUDGED A LITTLE TOWARDS GFS/MAV WHICH
RESULTS IN GUSTS THIS EVENING TO 50 MPH. EVEN WITH THE LOWER END
OF GUIDANCE WE SHOULD SEE BLOWING SNOW WITH REDUCED
VISIBILITIES. THE SPREAD IN GUIDANCE AND AND POSSIBLE LIMITED
DURATION OF THE STRONGEST WINDS IN OUR AREA RAISES QUESTIONS TO
HOW LOW THESE VISIBILITIES WILL BE AND HOW LONG. I FELT THE WINTER
WEATHER ADVISORY WAS APPROPRIATE WITH BRIEF BLIZZARD
CONDITIONS POSSIBLE. IF WINDS END UP BEING MORE IN LINE WITH GFS
SOLUTION WE MAY NEED TO CONVERT WESTERN LOCATIONS TO A BLIZZARD
WARNING...CONFIDENCE JUST ISNT THERE RIGHT NOW.
THE WORST CONDITIONS SHOULD BE 03Z THROUGH ABOUT 09Z TONIGHT...WITH
SNOW ENDING QUICKLY FROM THE WEST TO THE EAST EARLY THU MORNING.
WE COULD SEE LINGERING SNOW INTO THU IN OUR NORTHEAST...HOWEVER
WITH BEST FORCING/MOISTURE OUTSIDE OUR AREA I AM NOT ANTICIPATING
VERY MUCH ADDITIONAL ACCUMULATION. WE SHOULD SEE ANOTHER BLUSTERY
DAY THURSDAY WITH HIGHS IN THE 30S AND GUSTY WINDS THROUGH THE
DAY. GFS/MAV IS AGAIN MUCH HIGHER ON WINDS THU AND MIGHT SUPPORT
ADVISORY CRITERIA. I WILL HAVE TO SEE WHAT KIND OF BIAS THE GFS
HAD TONIGHT TO HAVE ANY ANY CONFIDENCE IN THE HIGHER WINDS THURSDAY.
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 345 AM MDT WED APR 17 2013
A SERIES OF WEAK SHORTWAVE TROUGHS WILL MOVE THROUGH THE CWA. AS
THE SHORTWAVES MOVE THROUGH THE AREA SATURDAY AFTERNOON THROUGH
SUNDAY AFTERNOON A CHANCE OF RAIN CAN BE EXPECTED. THE FORCING
THAT IS AVAILABLE SEEMS TO BE A LITTLE ON THE WEAK SIDE AND MUCAPE
IS NOT VERY GOOD (BELOW 200 J/KG)...HOWEVER WOULD NOT RULE OUT AN
ELEVATED ISOLATED TSTORM IN THE CWA BEHIND THE SURFACE TROUGH AXIS
SATURDAY AFTERNOON/EVENING.
MONDAY-TUESDAY NIGHT...A MORE POTENT UPPER LEVEL SHORTWAVE TROUGH
WITH A STRONG COLD FRONT WILL SWING THROUGH THE CWA ON MONDAY.
TIMING OF THE FROPA IS ALL OVER THE PLACE WITH THE MODELS...THE
ECMWF HAS IT MOVING THROUGH EARLY MONDAY MORNING WHILE THE GFS HAS
IT MOVING THROUGH LATER ON MONDAY. SINCE MODELS CAN/T COME TO A
CONSENSUS...DETERMINING PRECIP TYPE BECOMES MORE CHALLENGING MONDAY
NIGHT INTO TUESDAY MORNING...BELIEVE RIGHT NOW THAT PRECIP WILL
CHANGE FROM RAIN TO SNOW EARLY TUESDAY MORNING. ONCE THE TROUGH
MOVES THROUGH CANADIAN HIGH PRESSURE WILL SETTLE INTO THE CWA
CAUSING HIGH TEMPS TO BE COOLER IN THE MID TO UPPER 40S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1127 AM MDT WED APR 17 2013
THIS AFTERNOON...LOW STRATUS/IFR CIGS WILL PERSIST THROUGH THE
AFTERNOON...WITH LIFR VIS AT KGLD ASSOCIATED WITH DENSE
FOG/FREEZING DRIZZLE. SHORT RANGE GUIDANCE CONTINUES TO INDICATE
VIS IMPROVING EARLY THIS AFTERNOON...HOWEVER WITH NE FLOW AT THE
SURFACE AND MOIST BOUNDARY LAYER I ADJUSTED TAFS TO INDICATE
LINGERING LIFR CONDITIONS AT KGLD THROUGH 21Z WHEN SNOW OVER
EASTERN COLORADO SPREADS EAST AND SHOULD HELP MIX OUT THE LOW
LEVELS.
THIS EVENING-THURSDAY...WINTER STORM STILL EXPECTED TO IMPACT BOTH
TERMINALS STARTING THIS EVENING WITH LOW VIS ASSOCIATED WITH
SNOW/BLOWING SNOW EXPECTED THROUGH EARLY THURSDAY MORNING. LIGHT
SNOW/BLOWING SNOW MAY LINGER LONGER AT KMCK AS UPPER LEVEL SYSTEM
MOVES EAST. OVERALL VIS SHOULD IMPROVE TO VFR AT BOTH TERMINALS BY
SUNRISE...WITH CIGS IMPROVING TO MVFR BY MID MORNING THURSDAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WINTER WEATHER ADVISORY FROM 6 PM MDT /7 PM CDT/ THIS EVENING TO
6 AM MDT /7 AM CDT/ THURSDAY FOR KSZ001>004-013>016-027>029-
041-042.
CO...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM MDT
THURSDAY FOR COZ090>092.
NE...WINTER WEATHER ADVISORY FROM 6 PM MDT /7 PM CDT/ THIS EVENING TO
6 AM MDT /7 AM CDT/ THURSDAY FOR NEZ079>081.
&&
$$
SHORT TERM...DR
LONG TERM...ALW
AVIATION...DR
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1203 AM CDT WED APR 17 2013
.UPDATE...
ISSUED AT 912 PM CDT TUE APR 16 2013
00Z SND FROM TOP AND DOWNSTREAM AT DDC AND AMA SHOW A FAIRLY STOUT
CAP ON THE BOTTOM OF THE EML. PARCELS ABOVE THE SHALLOW COLD
AIR-MASS MAY NOT REACH THEIR LFC`S UNTIL LATE TONIGHT WHEN DEEPER
MOISTURE ADVECTION AND A STRENGTHENING LLJ MAY CAUSE PARCELS TO
REACH THEIR LFC. THE HRRR AND RAP MODELS SEEM TO BE THE BEST JOB
WITH INITIALIZATION AND MAY HAVE THE BEST PERFORMANCE WITH
ELEVATED CONVECTION. BOTH MODELS SHOW ELEVATED CONVECTION
DEVELOPING ACROSS CENTRAL AND NORTH CENTRAL KS BY 9Z...WITH THE
ELEVATED THUNDERSTORMS MOVING NORTHEAST ACROSS THE NORTHWEST
COUNTIES OF THE CWA THROUGH THE EARLY MORNING HOURS. ELEVATED
CONVECTION MAY FORM LATE TONIGHT ACROSS SOUTH CENTRAL AND CENTRAL KS AND
INTENSIFY AS IT MOVES NORTHEAST INTO THE REMAINDER OF THE CWA. THE
RAP INCREASES MUCAPE TO 1500 TO 2000 J/KG ACROSS THE WESTERN
COUNTIES OF THE CWA AFTER 12Z. WHILE SFC TO 6KM BULK SHEAR WILL BE
50 TO 60 KTS...THUS SOME OF THE ELEVATED THUNDERSTORMS MAY DEVELOP
MID-LEVEL MESO`S AND PRODUCE LARGE HAIL. THE BIG QUESTION
CONTINUES TO BE CAP STRENGTH...AND WHEN AND WHERE THE ELEVATED
THUNDERSTORMS WILL DEVELOP. MY THINKING IS BETWEEN 7Z-8Z ACROSS
NORTH CENTRAL KS WITH FARTHER DEVELOPMENT ACROSS THE REMAINDER OF
THE CWA TOWARDS 12Z.
SCATTERED SHOWERS MAY DEVELOP BEFORE ANY ELEVATED
CONVECTION DOES...THUS I KEPT SOME POPS THROUGH THE LATE EVENING AND
EARLY MORNING HOURS ACROSS THE CWA.
GARGAN
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 327 PM CDT TUE APR 16 2013
SOUTHWEST FLOW ALOFT CONTINUES ACROSS THE CENTRAL PLAINS AS A UPPER
TROUGH DIGS SOUTH ACROSS THE WESTERN U.S. THIS AFTERNOON AT 19Z.
SURFACE FRONTAL BOUNDARY WAS LOCATED FROM NORTHERN TEXAS NORTHEAST
INTO ARKANSAS AND SOUTHEAST MISSOURI. FURTHER NORTH OF THE WARM
FRONT CENTRAL AND EASTERN KANSAS REMAIN IN THE COOL SECTOR WITH
TEMPERATURES IN THE 40S.
FOR TONIGHT...ISENTROPIC LIFT INCREASES THIS EVENING AS PARCELS ARE
LIFTED OVER THE COLD DOME NORTH OF THE WARM FRONT. MOISTURE
TRANSPORT VECTORS INCREASE THIS EVENING AS THE LOW LEVEL JET
INCREASES. LAPSE RATES IN THE MID LEVELS WILL STEEPEN AND ELEVATED
INSTABILITY WILL INCREASE AS WELL ACROSS CENTRAL AND EASTERN KANSAS.
GIVEN FAVORABLE SHEAR...MOISTURE AND INSTABILITY TONIGHT SOME STORMS
MAY BECOME SEVERE AND PRODUCE LARGE HAIL OVERNIGHT.
WEDNESDAY...DIFFERENCES EXIST BETWEEN THE GFS AND THE NAM...ECMWF AS
WELL AS THE UKMET. THE GFS IS FURTHER NORTH WITH THE WARM SECTOR
WHILE THE OTHERS KEEP IT ACROSS EAST CENTRAL KANSAS IN THE
AFTERNOON. AGAIN FAVORABLE SHEAR...INCREASING INSTABILITY AND
MOISTURE WILL COME TOGETHER FOR STRONG TO SEVERE STORMS. THE MORNING
CONVECTION COULD STILL BE PRODUCING HAIL. BY AFTERNOON...AS PARCELS
RISE UP OVER THE FRONT INTO INCREASINGLY UNSTABLE AIR
HOWEVER...SEVERE HAIL WILL REMAIN THE PRIMARY THREAT FOR THE EASTERN
2/3 OF THE FORECAST AREA...WITH RISK OF SURFACE BASED
STORMS/TORNADIC THREAT GENERALLY ALONG AND SE OF THE INTERSTATE 35
CORRIDOR. IF THE WARM AIR IS FURTHER NORTH THEN THE CONVECTION WILL
INCREASE FURTHER NORTH AS WELL.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 327 PM CDT TUE APR 16 2013
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...
FRONT WILL CONTINUE TO PUSH SOUTH AND EAST OF I 35 THROUGH THE
EVENING. AS THE UPPER LEVEL TROUGH IN THE ROCKIES ADVANCES EASTWARD
INTO THE AREA STRONG FORCING AHEAD OF THE FRONT AND POST FRONTAL
WILL CONTINUE ACROSS THE NORTHEAST AND EAST CENTRAL AREAS...BUT
INSTABILITY WILL SLOWLY DECREASE THROUGH MIDNIGHT WITH AN ADDITIONAL
HALF OF ONE INCH OF RAIN...WITH LIGHTER AMOUNTS OF A QUARTER TO HALF
INCH IN THE NORTH CENTRAL. AS THE COLDER AND DRIER AIR ADVANCES EAST
WARD BEHIND THE FRONT...HIGH POPS ARE STILL WARRANTED...BUT PRECIP
AMOUNTS WILL BE ON THE DECLINE. AS THE COLDER AIR POURS INTO THE CWA
WEDNESDAY NIGHT INTO THURSDAY MORNING ON THE HEELS OF BLUSTERY NORTH
NORTHWEST WINDS...THERE IS A CHANCE FOR THE RAIN TO MIX WITH
SLEET...THEN SNOW IN THE FAR NORTH CENTRAL. UP TO AN INCH OF SNOW IS
POSSIBLE IN THE FAR NORTHWEST CORNER OF THE CWA BEFORE PRECIP
DECREASES TOWARDS MIDDAY. THE RAIN/SNOW MIX COULD MAKE IT AS FAR
EAST AS THE TURNPIKE ON THURSDAY AND LINGER OVER THE NORTHERN AND
EAST CWA THURSDAY EVENING ON THE BACKSIDE OF THE EXITING TROUGH.
AFTER LOWS WEDNESDAY NIGHT IN THE 40S EAST AND THE LOW TO MID 30S
WEST...HIGHS ON THURSDAY WILL ONLY RISE A FEW DEGREES FROM THE
MORNING LOWS.
A COLDER NIGHT IS IN STORE FOR THE AREA THURSDAY NIGHT WITH FREEZING
TEMPS EXPECTED IN MANY AREAS AS LOWS FALL INTO THE MIDDLE 20S NORTH
CENTRAL TO THE LOWER 30S NORTHEAST AND EAST CENTRAL. UNDER MOSTLY
SUNNY SKIES ON FRIDAY HIGH TEMPS WILL RECOVER BACK INTO THE UPPER
40S TO LOWER 50S.
FRIDAY THROUGH TUESDAY...
FRIDAY NIGHT THE LONG WAVE TROUGH WILL CONTINUE TO ADVANCE EASTWARD
AS SURFACE HIGH PRESSURE SETTLES OVERHEAD. WITH LIGHT WINDS AND A
COLD AIR MASS IN PLACE IT WILL BE QUIET CHILLY SATURDAY MORNING
AS LOW TEMPERATURES DROP INTO LOW 30S WHICH IS WELL BELOW NORMAL
THIS TIME OF YEAR. THIS MEANS THERE IS THE POTENTIAL FOR FROST
ACROSS PARTS OF THE REGION. ON SUNDAY A SHORTWAVE WILL DIVE
SOUTHEAST INTO THE NORTHERN AND CENTRAL PLAINS. AHEAD OF THE
APPROACHING SHORTWAVE LOW LEVEL SOUTHERLY FLOW WILL ALLOW MOISTURE
TO RETURN TO THE AREA. THIS BRINGS A CHANCE OF SHOWERS AND
THUNDERSTORMS ON SUNDAY AND MONDAY. THE MAIN TROUGH WILL PROGRESS
INTO THE NORTHERN US AND A TRAILING COLD FRONT WILL EXTEND SOUTH
ACROSS THE REGION. BEHIND THE COLD FRONT ANOTHER SHOT OF
UNSEASONAL COLD AIR WILL FILTER SOUTH ACROSS THE AREA. THE ECMWF
IS SUGGESTING POST FRONTAL PRECIPITATION WHICH WOULD MEAN A MIX OF
RAIN AND SNOW MONDAY NIGHT AND TUESDAY MORNING. DUE TO LOW
UNCERTAINTY DID NOT ADD SNOW INTO THE FORECAST ATTM. THIS SHOT OF
COLD AIR COULD ALSO BRING ANOTHER CHANCE OF FROST MONDAY
NIGHT...BUT WILL HAVE TO MONITOR ADDITIONAL MODEL OUTPUT BEFORE
ADDRESSING THE DETAILS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1200 AM CDT WED APR 17 2013
MVR CEILINGS WILL GRADUALLY DROP TO THE IFR CATEGORY THROUGH THE
EARLY MORNING HOURS. SHOWERS AND THUNDERSTORMS WILL DEVELOP
THROUGH THE MORNING...THEN WE MAY SEE A BREAK IN THE LATE MORNING
BEFORE SHOWERS AND THUNDERSTORMS REDEVELOP AND CONTINUE INTO THE
EVENING. THERE MAY BE A WINDOW OF MVFR CEILINGS THIS AFTERNOON BUT
IFR CEILINGS SHOULD DEVELOP BEHIND THE COLD FRONT THIS EVENING.
GARGAN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GARGAN
SHORT TERM...53
LONG TERM...SANDERS/63
AVIATION...GARGAN
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
416 PM EDT THU APR 18 2013
.SYNOPSIS...
HIGH PRESSURE SHIFTS FARTHER OFF THE COAST TONIGHT AS A STRONG COLD
FRONT MOVES ACROSS THE OHIO AND TENNESSEE VALLEYS. THIS COLD FRONT
WILL TRACK THROUGH THE MID ATLANTIC REGION FRIDAY NIGHT. CANADIAN
HIGH PRESSURE BUILDS ACROSS THE NORTHEAST OVER THE WEEKEND AS A
FRONTAL BOUNDARY REMAINS STALLED OFF THE SOUTHEAST COAST.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE LATEST SURFACE ANALYSIS INDICATES A ~1030MB HIGH CENTERED OVER
NOVA SCOTIA...WITH A DEEPENING 996MB LOW PRESSURE CENTER TRACKING
NNE THROUGH THE MID-MISSISSIPPI VALLEY. AN ASSOCIATED COLD FRONT
EXTENDS SOUTHWARD THROUGH THE LOWER MISSISSIPPI VALLEY...WITH A WARM
FRONT EXTENDING ENE THROUGH THE GREAT LAKES. ADDITIONALLY...THERE
REMAINS A DIFFUSE OLD FRONTAL BOUNDARY ALIGNED N-S ACROSS EASTERN PA
AND EXTENDING S AND CLIPPING THE ATLANTIC COAST OF THE LOWER MD
EASTERN SHORE. THIS HAS PRODUCED PERSISTENT FOG AND STRATUS ALONG
THE IMMEDIATE COAST. NUMERICAL AND STATISTICAL MODEL GUIDANCE IS
RATHER PESSIMISTIC WITH RESPECT TO FOG AND STRATUS OVERNIGHT.
HOWEVER...STRENGTHENING SW FLOW ALOFT AND S/SE FLOW AT THE SURFACE
AROUND THE WESTERN PERIPHERY OF THE HIGH WOULD SUPPORT MORE OF A
STRATUS SITUATION RATHER THAN FOG. AT THIS TIME...AREAS OF FOG WILL
BE MAINTAINED FOR THE IMMEDIATE ATLANTIC COAST (AND ADJACENT
COASTAL MARINE AREAS)...WITH A PATCHY FOG MENTION ELSEWHERE FOR THE
EASTERN SHORE.
WITH INCREASING MOIST SSE FLOW AROUND THE HIGH AND AHEAD OF THE
FRONT AN ISOLATED SHRA/TSRA ACRS THE PIEDMONT IS POSSIBLE...BUT A
DRY FORECAST WILL BE MAINTAINED FOR NOW...AS THERE WILL BE LITTLE TO
TRIGGER FOR PRECIP. VERY WARM UNDER STRENGTHENING SOUTHERLY FLOW AND
WILL CONTINUE ON THE WARM SIDE OF GUIDANCE WITH LOWS IN THE LWR 60S
FOR MUCH OF THE CWA...LOCALLY IN THE 50S NEAR THE COAST.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
A GENERAL CONSENSUS REMAINS AMONGST NUMERICAL MODEL DYNAMICAL AND
MOISTURE FIELDS WITH RESPECT TO THE APPROACHING FRONTAL SYSTEM.
THERE COULD BE A FEW LIGHT SHOWERS IN MOIST SSE FLOW WELL AHEAD OF
THE BOUNDARY FRIDAY MORNING. HOWEVER...NOT MUCH IS EXPECTED THROUGH
21Z DUE TO A RATHER ROBUST MID-LEVEL STABLE LAYER. MORNING STRATUS
SHOULD GIVE WAY TO A PARTLY SUNNY SKY. BREEZY CONDITIONS ARE
EXPECTED TO DEVELOP BY AFTERNOON WITH A SOUTHERLY WIND OF 15-20
MPH...WITH GUSTS TO 30 MPH POSSIBLE FROM I-95 EASTWARD TO THE COAST.
HIGH TEMPERATURES WILL RISE INTO THE UPPER 70S/LOW 80S FOR MOST OF
THE AREA...WITH THE EXCEPTION OF LOWER VALUES ALONG THE IMMEDIATE
ATLANTIC COAST OF THE EASTERN SHORE.
THE STRONGEST FORCING FOR CONVECTION ARRIVES IN THE WESTERN PORTION
OF THE AREA CLOSER TO 00Z AND REACHES THE COAST AROUND 06Z. THE
GENERAL CONSENSUS AMONGST RELATIVELY COARSER RESOLUTION MODELS IS A
NARROW ZONE OF 500-750 J/KG OF MLCAPE ALONG THE LEADING EDGE OF THE
BOUNDARY ALONG WITH 40-45KT OF DEEP LAYER (0-6KM) SHEAR.
HOWEVER...HIGH-RES DATA SUGGESTS THERE COULD INITIALLY BE 750-1000
J/KG OVER THE PIEDMONT BEFORE DIMINISHING AS THE FRONT TRANSLATED
EASTWARD. THIS COULD FAVOR A NARROW LINE OF THUNDERSTORMS ALONG THE
LEADING EDGE WITH THE POTENTIAL FOR A STRONG WIND GUSTS. SPC HAS
ISSUED A SLIGHT RISK OF SEVERE...BUT A SIGNIFICANT SEVERE OUTBREAK
IS NOT EXPECTED.
THE FRONT BECOMES MORE ANAFRONTAL AS THE NIGHT PROGRESSES WITH A
STEADY RAIN DEVELOPING. PW VALUES RISE TO 1.5-1.7IN (AROUND +2 ST
DEV) FOR MID-APRIL. THIS SHOULD RESULT IN AROUND 0.75-1.25IN OF RAIN
FOR MUCH OF THE AREA WITH THE HIGHEST AMOUNTS ACROSS SE VA/NE NC
WHERE RAIN COULD LINGER INTO SATURDAY MORNING (AND LOCALLY HIGHER
AMOUNTS WILL BE POSSIBLE DUE TO THE CONVECTIVE NATURE OF THE PRECIP
INITIALLY). STILL DO NOT SEE THIS EVENT LEADING TO ANYTHING MORE THAN
MINOR/NUISANCE FLOODING IN POOR DRAINAGE AREAS AS BULK OF THE BEST
FORCING OCCURS POST FRONTAL WITH TEMPERATURES IN THE 50S AND
60S...AS WELL AS FACT THAT APRIL FLASH FLOOD EVENTS ARE RARE IN THE
AKQ CWA. LOW TEMPERATURES SHOULD RANGE FROM THE UPPER 40S NW...TO
THE LOW 50S SE...BUT WILL REMAIN MILD AHEAD OF THE FRONT WELL INTO
FRIDAY EVENING FOR EASTERN AREAS.
A STRONG AREA OF HIGH PRESSURE BUILDS ACROSS NEW ENGLAND THROUGH THE
WEEKEND...POTENTIALLY 1040+ MB BY SUNDAY. MEANWHILE...THE A PORTION
OF THE FRONTAL BOUNDARY STALLS OFF THE SOUTHEAST COAST. THIS WILL
LEAD TO PERSISTENT ONSHORE FLOW THROUGH THE WEEKEND. HIGHS SATURDAY
SHOULD RANGE FROM THE LOW 60S E...TO MID 60S W...AND SUNDAY HIGHS
SHOULD RANGE FROM THE UPPER 50S E...TO LOW 60S W. THE SKY SHOULD BE
MOSTLY SUNNY SATURDAY AND SUNDAY FOR MUCH OF THE AREA WITH CLOUD
COVER LINGERING OVER SE PORTIONS SATURDAY AFTERNOON. LOWS SUNDAY
MORNING SHOULD BE IN THE MID 30S OVER THE PIEDMONT TO THE LOW/MID
40S OVER SE PORTIONS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
HIGH PRESSURE OVER ATLANTIC CANADA WILL SLIDE TO THE EAST. A
SOUTHERN STREAM SHORT WAVE WILL INITIATE AN INVERTED SURFACE
TROUGH OFF THE CAROLINA COAST BY MONDAY. THIS DEVELOPS INTO A LOW
PRESSURE SYSTEM TUESDAY WHICH WILL MOVE TO THE NORTHEAST. A GOOD
CHANCE FOR PCPN DEVELOPS FROM THE SOUTH MONDAY. EURO KEEPS THE PCPN
CLOSER TO THE COAST AND THE GFS SPREADS IT WELL INLAND. FOLLOWED
CLOSE TO HPC POPS WHICH BRINGS 30 PERCENT POPS MONDAY INCREASING TO
40 PERCENT ERN PORTIONS. POPS DROP OFF FROM S TO N ON TUESDAY.
MODELS ARE IN GOOD AGREEMENT WITH A COLD FRONT CROSSING THE MID
ATLANTIC STATES SOMETIME WEDNESDAY NIGHT. THE GFS LOOKS TOO FAST AND
IS ABOUT 12 HOURS QUICKER THAN THE EURO. WENT WITH HPC GUIDANCE
WHICH IS CLOSEST TO THE EURO TIMING AND HAS THE FRONT MOVING OFF THE
COAST BY EARLY THURSDAY MORNING. CHC FOR SHOWERS INCREASES FROM THE
WEST WEDNESDAY. DID NOT INCLUDE TSTMS FOR WEDNESDAY IN THE GRIDS BUT
THEY WILL NEED TO BE CONSIDERED WITH LATER ISSUANCES. HAVE 30-40
PERCENT POPS WEDNESDAY INCREASING TO 40 PERCENT POPS FOR WEDNESDAY
NIGHT AND HAVE 30-40 PERCENT FOR POST FRONTAL ACTIVITY ON THURSDAY.
IT APPEARS THAT THE AIR BEHIND THE FRONT WILL BE UNSTABLE WITH
FAIRLY COLD AIR ALOFT.
HIGH TEMPERATURES AROUND 60 MONDAY EXCEPT MID 50S NEAR THE COAST
WARM ON WEDNESDAY TO THE MID 60S NEAR THE COAST TO THE LOWER 70S
INLAND. TEMPERATURES COOL BACK TO THE 60S THURSDAY. LOW TEMPERATURES
IN THE LOW TO MID 40S MONDAY MORNING WARM TO THE 50S BY WEDNESDAY
MORNING AND COOL A BIT BY THURSDAY MORNING.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
WARM FRONT HAS MOVED NORTH OF THE AREA. GENERALLY SOUTHERLY FLOW
ACROSS THE AREA AND THIS WILL CONTINUE THROUGH THE NIGHT. CAN SEE
FOG STILL ALONG THE MD COAST AND MODELS ALL EXPAND THAT WEST WITH
TIME ACROSS SBY AFTER SUNSET. TIMED SBY TO START COMING DOWN BY
03Z AND CONTINUE TO BE IFR THROUGH 14Z. THINK ENOUGH MIXING WILL
BE OCCURRING BY THEN WITH THE SUN UP TO GET RID OF LOW CLOUDS.
BUFKIT SHOWS THESE CLOUDS ON BOTH THE RAP AND NAM MODELS TO BE
QUITE THIN. THE STATISTICAL GUIDANCE DOES NOT CLEAR IT OUT BUT IT
HAS BEEN HOLDING ON TO THE LOW CEILING TOO LONG THIS MORNING. ALSO
THE MODELS KEEP TRYING TO BRING THE OTHER TAF SITES DOWN TO IFR
AFTER MIDNIGHT BUT WITH 10 KTS OF WINDS AND ALL MODELS AGREEING
THAT THE MOISTURE IS CONFINED BELOW 925 MB THINK THE MIXING WILL
KEEP THE LOW CLOUDS AWAY OVERNIGHT. THEN ON FRIDAY WITH STRONG
COLD FRONT APPROACHING WILL HAVE BKN CU DEVELOP ACROSS THE AREA
DURING THE MORNING. THE PRECIPITATION WITH THE FRONT WILL REACH
RIC NEAR 00Z AND THERE WILL BE SOME THUNDERSTORMS ALONG THE
LEADING EDGE OF THE FRONT. MORE RAIN WILL CONTINUE FOR SEVERAL
HOURS BEHIND THE FRONT. THIS WILL BRING IFR CONDITIONS TO ALL TAF
SITES FOR FRIDAY NIGHT. CONDITIONS WILL IMPROVE RAPIDLY ON SAT
DURING THE MORNING WITH VFR CONDITIONS EXPECTED ALL AREAS BY
AFTERNOON AND CONTINUING INTO SUNDAY. COULD SEE SOME MVFR OR IFR
CONDITIONS RETURN BY MONDAY WITH BEST CHANCES NEAR THE COAST.
&&
.MARINE...
WINDS INCREASE FROM THE SE/S OVERNIGHT. HAVE SCA IN THE BAY WITH
CHANNELING EFFECT CONTRIBUTING TO THE WINDS REACHING NEAR 20 KNOTS
AT TIMES. SEAS IN THE COASTAL WATERS SLOWLY BUILD AND HAVE SCA BEGIN
IN THE NORTH BY 02Z SPREADING TO THE SOUTHERN WATERS FRIDAY MORNING.
WINDS IN THE BAY SUBSIDE BY OR SHORTLY AFTER MIDNIGHT BUT SCA
CONDITIONS RESUME FRIDAY MORNING AS WINDS INCREASE OVER ALL THE
WATERS FROM THE SOUTH. THIS OCCURRING AHEAD OF A STRONG COLD FRONT
THAT MOVES THROUGH FRIDAY NIGHT.
WINDS SHIFT TO THE NW FRIDAY NIGHT BUT WINDS ARE NOT EXPECTED TO BE
PARTICULARLY STRONG. SCA DROP OFF EARLY SATURDAY MORNING. SCA MAY
NEED TO BE EXTENDED WITH LATER ISSUANCES IN THE COASTAL WATERS FOR
SEAS OF 5 FEET OR HIGHER.
THE PRESSURE GRADIENT BETWEEN STRONG HIGH PRESSURE TO THE NORTH AND
DEVELOPING LOW PRESSURE OFF THE CAROLINA COAST WILL GENERATE AN
EXTENDED PERIOD OF NE WINDS AND SEAS OF 5 FT OR HIGHER. SCA MAY BE
NEEDED IN THE COASTAL WATERS FOR THIS BY SUNDAY MORNING AND LAST
INTO LATE MONDAY OR TUESDAY.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM FRIDAY TO MIDNIGHT EDT FRIDAY
NIGHT FOR ANZ635>638.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR ANZ630>632-
634.
SMALL CRAFT ADVISORY FROM NOON FRIDAY TO 4 AM EDT SATURDAY FOR
ANZ633.
SMALL CRAFT ADVISORY FROM 4 AM FRIDAY TO 7 AM EDT SATURDAY FOR
ANZ654.
SMALL CRAFT ADVISORY FROM 10 AM FRIDAY TO 7 AM EDT SATURDAY
FOR ANZ656-658.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 7 AM EDT
SATURDAY FOR ANZ650-652.
&&
$$
SYNOPSIS...AJZ
NEAR TERM...AJZ
SHORT TERM...AJZ/LKB
LONG TERM...LSA
AVIATION...JAB
MARINE...LSA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
411 AM EDT WED APR 17 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 436 PM EDT TUE APR 16 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
NRN QUEBEC THROUGH JAMES BAY INTO NRN ONTARIO WAS DEPARTING TO THE
EAST. UPSTREAM...SW FLOW PREVAILED THROUGH THE PLAINS AHEAD OF A
TROUGH FROM THE NRN ROCKIES THROUGH THE GREAT BASIN. WITH CONFLUENT
FLOW WITH QVECTOR DIV AND SUBSIDENCE OVER THE NRN GREAT LAKES...THE
SCT FLURRIES HAD DIMINISHED THIS AFTERNOON.
AS HIGH PRES BUILDS INTO NRN ONTARIO TONIGHT BRINGING ENE ACYC FLOW
INTO UPPER MI AND DAYTIME HEATING FADES...EXPECT THAT WINDS WILL
DIMINISH AND CLOUDS WILL THIN OUT ENOUGH FOR TEMPS TO DROP INTO THE
20S.
AS THE WRN TROUGH EDGES TO THE EAST AND A SFC-850 MB TROUGH DEVELOPS
FROM THE SRN PLAINS INTO THE UPPER MS VALLEY...WAA AND MOISTURE
ADVECTION WILL INCREASE QUICKLY BY WED AFTERNOON. THE INITIAL AREA
OF PCPN IS EXPECTED INTO THE WEST...WHERE 295K-300K ISENTROPIC LIFT
IS STRONGEST. GIVEN THE DRY ERLY FLOW AS THE HIGH GRADUALLY MOVES
EAST THROUGH NRN ONTARIO...THE SLOWER PROGRESSION OF PCPN INTO
UPPER...PER NAM...WAS PREFERRED COMPARED TO THE GFS/ECMWF. EXPECT
ENOUGH OF A LINGERING WARM LOWER LAYER FOR MOSTLY RAIN AT THE ONSET
OF MAINLY LIGHT PCPN AS AFTERNOON TEMPS CLIMB INTO THE 40F TO 45F
RANGE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 436 PM EDT TUE APR 16 2013
MAIN ATTENTION FOR THE LONG TERM PORTION OF THE FORECAST ARE THE
TWO WAVES OF PRECIPITATION ASSOCIATED WITH ENERGY AND LOW PRESSURE
SYSTEMS EXITING FROM THE UPPER TROUGH CURRENTLY MOVING THROUGH THE
WESTERN CONUS.
FIRST WAVE WILL BE INFLUENCING THE AREA AT THE START OF THE LONG
TERM PERIOD WILL BE ASSOCIATED WITH SHORTWAVE ENERGY EJECTING AHEAD
OF THE TROUGH EXPECTED TO BE IN THE CENTRAL ROCKIES. AT THE
SURFACE...A LOW CENTERED IN WESTERN OKLAHOMA AND THE
PANHANDLE OF TEXAS WILL BEGIN ELONGATING A TROUGH NORTHEAST INT HE
MID MISSISSIPPI VALLEY ON WEDNESDAY AFTERNOON AND THEN NORTHEAST
INTO NORTHERN LAKE MICHIGAN BY 12Z THURSDAY. WITH THE STRONG MID
LEVEL FORCING ASSOCIATED WITH 925-700MB WARM AIR ADVECTION AND
LIKELY CONVECTION ON THE EAST SIDE OF THE TROUGH...WOULD EXPECT THE
HEAVIEST PRECIPITATION TO BE JUST TO THE SOUTHEAST OF THE CWA OR
BRUSH THE SOUTHEAST PART OF THE CWA. BUT...WITH THE AREA UNDER THE
RIGHT REAR OF THE UPPER JET AND ENOUGH OVERRIDING FLOW WITH THAT
WARM AIR ADVECTION AND ISENTROPIC ASCENT ON THE 280-300K
SFCS...STILL THINK THAT THERE WILL BE ENOUGH FORCING FOR MODERATE
PRECIPITATION ACROSS MUCH OF THE CWA. GENERAL MODEL CONSENSUS OF
0.50-0.80 INCH SEEMS REASONABLE FOR MUCH OF THE AREA...WITH VALUES
APPROACHING AN INCH ALONG THE LAKE MICHIGAN SHORELINE. THIS TRICKY
PART OF THIS FORECAST IS WHAT AMOUNT OF THE PRECIP WILL FALL AS
RAIN OVER THE WESTERN HALF OF THE CWA DUE TO THE ELEVATED WARM
LAYER. THERE CONTINUES TO BE SOME DISCREPANCY IN THE AMOUNT OF WARM
AIR THAT MOVES OVER THE CENTRAL CWA AND HOW FAR WEST THAT MOVES.
THINK THE FAR WESTERN CWA WILL LIKELY SEE MAINLY SNOW /FROM
KCMX TO KIWD/...BUT COULD SEE A BRIEF PERIOD OF FREEZING RAIN
OVERNIGHT. THE AREA BETWEEN THERE AND A LINE FROM MARQUETTE TO IRON
MOUNTAIN IS THE TRICKY AREA...SINCE THERE WILL LIKELY BE ENOUGH
WARM AIR TO MELT THE SNOW ALOFT. THEN PRECIP TYPE COMES DOWN TO
SURFACE TEMPERATURES...SINCE 925MB TEMPS ARE WELL BELOW FREEZING.
WILL CONTINUE TO MENTION MAINLY FREEZING RAIN IN THAT AREA...WITH
SOME MENTION OF SNOW. ALL IN ALL...APPEARS THAT THIS WILL LIKELY BE
A SOLID ADVISORY FOR THE WESTERN HALF OF THE CWA AND THERE IS SOME
CONCERN FOR DECENT ICE ACCUMULATION DEPENDING ON WHAT THE SURFACE
TEMPS ARE. THIS ENERGY WILL SHIFT NORTHEAST ON THURSDAY MORNING AND
WITH THE 850MB FLOW BECOMING MORE SOUTHWEST...WOULD EXPECT THE
PRECIPITATION TO WEAKEN HEADING INTO THE AFTERNOON.
NEXT SYSTEM TO AFFECT THE AREA WILL BE AS THE UPPER TROUGH LIFTS TO
THE NORTHEAST AND MOVES TOWARDS THE UPPER GREAT LAKES ON THURSDAY
NIGHT INTO FRIDAY. THIS WILL INTENSIFY A LOW ALONG THE LINGERING
SURFACE TROUGH AND THEN LIKELY TRACK TOWARDS THE STRAITS OF
MACKINAC BY 12Z FRIDAY. THE MAIN CONCERN FOR WIDESPREAD
PRECIPITATION FOR THE AREA IS THE TRACK/LOCATION OF THE DRY SLOT
SURGING NORTHEAST ON THURSDAY NIGHT INTO FRIDAY. THERE ARE STILL
SOME DIFFERENCES IN THE LOW TRACK WITH THE NAM/GEM...SO OPTED TO
FOLLOW THE MORE CONSISTENT IDEA OF THE GFS/ECMWF FOR THE FORECAST.
LATEST INDICATIONS IN THE MODELS THAT THE DRY SLOT WILL AFFECT THE
CENTRAL/EASTERN CWA...BETWEEN THE DEFORMATION PRECIPITATION
AFFECTING THE WESTERN CWA AND THE CONVECTION AND HEAVY RAIN
AFFECTING LOWER MICHIGAN AHEAD OF THE COLD FRONT. THUS...WOULD
EXPECT THE HEAVIEST PRECIPITATION TO OCCUR OVER THE WESTERN THIRD OF
THE CWA THURSDAY NIGHT INTO FRIDAY...WITH THE REST OF THE AREA
SEEING LIGHTER PRECIPITATION. BASED OFF THE THERMAL PROFILE...THAT
ALSO SEEMS TO BE THE LOCATION OF THE RAIN/SNOW/MIXED PRECIPITATION
LINE...LARGELY STRETCHING FROM KIMT/KSAW. THE CONCERN FOR THE
CENTRAL CWA WILL BE THE EXPECTED AREA OF SUBFREEZING TEMPERATURES
BELOW 875MB WHICH WOULD LEAD TO THE RAIN FREEZING WHEN IT GETS TO
THE SURFACE. OUT WEST...THE PRECIPITATION WILL LIKELY START OUT AS
FREEZING RAIN AS THE WARM NOSE ROTATES THROUGH AND THEN TRANSITION
TO SNOW FROM WEST TO EAST. WHEN COMBINED WITH THE NORTHERLY FLOW OFF
LAKE SUPERIOR WITH 850MB TEMPS FALLING TO -10C ON FRIDAY SHOULD SEE
LAKE ENHANCEMENT REALLY INCREASE AMOUNTS OVER GOGEBIC/ONTONAGON
COUNTIES THROUGH THE DAY ON FRIDAY. WITH THAT AREA SEEING BOTH THE
DEFORMATION PRECIPITATION AND THE LAKE ENHANCEMENT...CURRENT
EXPECTATION WOULD BE WARNING SNOWFALL AMOUNTS AND SOME LOCATIONS
COULD SEE SOME SIGNIFICANT SNOWFALL AMOUNTS FOR MID-LATE APRIL. IN
ADDITION TO THE SNOW...STRONG NORTHERLY WINDS FROM THE KEWEENAW
THROUGH GOGEBIC COUNTY WILL LEAD TO NEAR BLIZZARD CONDITIONS EVEN
THOUGH THE SNOW WILL LIKELY BE ON THE WETTER SIDE INITIALLY.
WILL CONTINUE THE SPS FOR THE WEDNESDAY NIGHT THROUGH FRIDAY
PERIOD...SINCE I FEEL THAT ENCOMPASSES THE ENTIRE SYSTEM WELL AND
SINCE THE THE MOST SIGNIFICANT EVENT WILL BE THE SECOND SYSTEM.
COULD HAVE DONE A LONG PERIOD WATCH TO COVER BOTH EVENTS...BUT SINCE
THE FIRST WAVE SEEMS TO BE MORE OF AN ADVISORY SITUATION AND THEN A
BRIEF BREAK ON THURSDAY AFTERNOON...WASN`T SURE IF THAT WOULD COME
ACROSS WELL WITH A LONG TERM WATCH HEADLINE.
EXPECT THE LAKE ENHANCED SNOW TO CONTINUE INTO FRIDAY NIGHT BUT
WILL QUICKLY COME TO AN END ON SATURDAY AS THE UPPER TROUGH LIFTS
TO THE NORTHEAST AND SURFACE HIGH PRESSURE BUILDS OVER THE AREA.
THIS SHOULD LEAD TO A NICE BUT COOL START TO THE WEEKEND...WITH
HIGHS ONLY REACHING THE 30S IN MOST LOCATIONS. THEN AS THE HIGH AND
UPPER RIDGE SHIFTS TO THE EAST ON SUNDAY...THE NEXT WAVE FROM THE
PACIFIC NORTHWEST WILL BE APPROACHING THE AREA FOR SUNDAY NIGHT AND
CONTINUING INTO MONDAY NIGHT AND TUESDAY. THERE CONTINUES TO BE
SOME DIFFERENCES IN THE DETERMINISTIC MODELS AND THERE ENSEMBLE
MEANS...BUT THE GENERAL IDEA OF THE UPPER TROUGH AND COLD FRONT
MOVING THROUGH THE AREA DURING THAT TIME SEEMS REASONABLE. THE AREA
WILL LIKELY SEE A BRIEF WARM UP FOR SUNDAY INTO MONDAY...BACK INTO
THE 40S...BUT THEN COOL TO BELOW NORMAL VALUES BEHIND THE COLD FRONT
ON TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 410 AM EDT WED APR 17 2013
BAND OF MOISTURE/MVFR CIGS THAT HAS BEEN DRIFTING S ACROSS NRN
ONTARIO AND LAKE SUPERIOR SHOULD LEAD TO OCNL MVFR CIGS AT KCMX/KSAW
OVERNIGHT INTO THE MORNING HRS. MVFR CIGS SHOULD THEN SCATTER OUT BY
LATE MORNING. AT KIWD...DOWNSLOPE COMPONENT TO DEVELOPING LIGHT
EASTERLY WIND SHOULD WORK TO MAINTAIN VFR CONDITIONS THRU THE NIGHT.
SURGE OF WARM/MOISTURE N INTO THE GREAT LAKES LATE THIS AFTN/TONIGHT
WILL BRING A WINTRY MIX OF PCPN TO ALL 3 SITES. EXPECT PCPN TO BEGIN
AS -SN OR BRIEFLY -SNRA AT KIWD EARLY EVENING AND THEN MIX WITH PL
BY LATE EVENING AS WARMER AIR ALOFT CONTINUES TO SURGE N. DOWNSLOPE
COMPONENT TO E WIND SHOULD HELP TO KEEP CONDITIONS FROM FALLING BLO
MVFR AT KIWD. FARTHER INTO THE COLD AIR...PCPN SHOULD BE ALL SN AT
KCMX WHEN IT BEGINS IN THE EVENING. EXPECT CONDITIONS AT KCMX TO
FALL TO IFR SOON AFTER THE SNOW BEGINS DUE TO UPSLOPE E WIND. AT
KSAW...PCPN SHOULD BEGIN AS -SNPL IN THE EVENING AND THEN MIX WITH
OR CHANGE TO MAINLY -FZRA BY LATE EVENING. CONDITIONS AT KSAW SHOULD
FALL TO LOW MVFR...PERHAPS IFR...AFTER THE PCPN BEGINS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 436 PM EDT TUE APR 16 2013
WINDS WILL STAY BELOW 30 KNOTS THROUGH THU BEFORE INCREASING OUT OF
THE NORTH THURSDAY NIGHT INTO FRIDAY NIGHT WHEN NORTH GALES ARE
LIKELY AS A DEEP LOW PRESSURE SYSTEM MOVES TOWARD NORTHERN LAKE
MICHIGAN AND EAST UPPER MICHIGAN. THERE IS THE POTENTIAL FOR HIGHER
END GALES WITH THIS SYSTEM IN THE 40 TO 45 KNOT RANGE. THE WINDS
WILL DIMINISH FRI NIGHT INTO SAT AS THE LOW MOVES QUICKLY TO THE
NORTHEAST OF THE REGION AND HIGH PRES BUILDS IN FROM THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EDT
THURSDAY FOR MIZ001-003>005-084.
WINTER WEATHER ADVISORY FROM 8 PM EDT /7 PM CDT/ THIS EVENING TO
10 AM EDT /9 AM CDT/ THURSDAY FOR MIZ002-009.
LAKE SUPERIOR...
GALE WATCH FROM LATE THURSDAY NIGHT THROUGH LATE FRIDAY NIGHT
FOR LSZ263>266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
355 PM CDT THU APR 18 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 249 PM CDT THU APR 18 2013
IMPRESSIVE DEFORMATION SNOW EVENT WELL UNDERWAY...WITH STRONG FGEN
NOTED IN THE H8-H5 LAYER. SEEING CONVECTIVE ELEMENTS COMING UP OUT
OF IOWA...WHICH IS AN INDICATION OF THE INSTABILITY PRESENT...WITH
SEVERAL HEAVY BANDS OF SNOW NOTED ON RADAR AS A RESULT. HAVE
GOTTEN REPORTS OF AROUND 2 INCHES PER HOUR OUT IN WRN MN THIS
AFTERNOON...AND EXPECT THESE SORTS OF RATES TO CONTINUE THROUGH
THE AFTERNOON.
THROUGH TONIGHT...FOLLOWED THE RAP FAIRLY CLOSELY FOR FORECAST
UPDATES TODAY...AS IT HAS HAD A PRETTY GOOD HANDLE ON HOW THINGS
HAVE UNFOLDED ALL DAY. AS A RESULT...BOOSTED SNOW TOTALS SOME
WITHIN THE HEART OF THE BAND FROM REDWOOD FALLS UP THROUGH ST.
CLOUD...WITH 6 INCH AMOUNTS CREEPING EAST TO BE ACROSS THE EAST
END OF THE WARNING COUNTIES NOW...WITH SNOW TOTAL AT MINNEAPOLIS
INCREASED FROM AROUND 3 INCHES TO 6 INCHES. IF THE RAP WERE TO BE
BELIEVED /WHICH BASED ON REPORTS SEEN SO FAR...DO NOT SEE WHY IT
CAN NOT BE/...THEN WE WILL LIKELY END UP WITH A BAND OF 10 TO 12
INCHES FROM GRANITE FALLS OVER TO NEW ULM AND UP TO LONG PRAIRIE
OVER TO MORA. WITH UPDATES MADE TO FORECAST TODAY...DID ADD TODD
COUNTY TO THE WARNING AND COULD HAVE VERY EASILY ADDED
STEVENS AND DOUGLAS COUNTIES OUT WEST...ALONG WITH ANOTHER ROW OF
COUNTIES TO THE EAST OF THE WARNING THAT WOULD INCLUDE THE REST OF
THE TWIN CITIES. IN FACT...AS OF THE WRITING OF THIS...THINKING
WE WILL GO AHEAD AND EXPAND THE WARNING EAST AND WEST WHEN DONE
WITH THIS AFD TO INCLUDE ALL OF THE TWIN CITIES METRO AREA.
HEAVY SNOW WILL START LETTING UP AFTER 21Z SW OF THE MN
RIVER...BETWEEN 0Z AND 3Z ALONG I-94 FROM THE TWIN CITIES UP
THROUGH ST. CLOUD...WITH HEAVY SNOW PULLING OUT OF THE NRN CWA
SHORTLY AFTER 06Z. LIGHT SNOW WILL CONTINUE THROUGH TONIGHT...WITH
LIGHT SNOW SHOWERS CONTINUING THROUGH THE DAY ACROSS WRN
WI ON FRIDAY...THOUGH MAJORITY OF ACCUMULATIONS WILL BE COMING
NOW THROUGH 12Z FRIDAY. FOR FRIDAY...ANY ADDITIONAL ACCUMULATIONS
WILL BE UNDER AN INCH.
AT 230 PM...THE RAIN/SNOW LINE WAS LOCATED NEAR AN ALBERT LEA
THROUGH RICE LAKE LINE...AND AGAIN GENERALLY FOLLOWED THE
RAP...WITH ALL SNOW FINALLY BREAKING OUT IN THE EAU CLAIRE AREA
AROUND 3Z.
AS FOR TEMPERATURES...CLOUD COVER AND NW WINDS WILL RESULT IN
FAIRLY STEADY TEMPERATURES THROUGH FRIDAY...WITH LOWS TONIGHT
FALLING BACK INTO THE UPPER 20S/LOWER 30S WHILE HIGHS ON FRIDAY
STAY MIRED IN THE 30S...OR ABOUT 20 DEGREES BELOW NORMAL.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 330 PM CDT THU APR 18 2013
SHORT DRY WINDOW WILL BE ENCOUNTERED ACROSS MUCH OF THE FA
FRIDAY NIGHT INTO MUCH OF SUNDAY AS 1025MB HIGH PRESSURE DOME
SETTLES OVER THE REGION. COPIOUS AMOUNTS OF RESIDUAL MOISTURE
FROM CURRENT SNOWSTORM COUPLED WITH RADIATIONAL
COOLING...LIGHT WINDS...SHOULD PORTEND SCT TO AREAS OF FOG
OVER MUCH OF THE CWA BETWEEN 20/06Z-20/13Z. ONLY FLY IN THE
OINTMENT WOULD BE ADVECTION OF MID TO HIGH LEVEL CLD DECK
ASSOICATED WITH NEXT SYSTEM ENTERING FAR EASTERN MONTANA
AND WYOMING.
RAMPED UP POPS SLIGHTLY FOR SAT EVE-TUE AFTN STORM EVENT.
WEAK SFC CYCLONE ASSOCIATED WITH SAME WILL TREK FROM SE
MONTANA SUNDAY AFTN TO NE NEBRASKA BY MON/12Z. ALTHOUGH
PASSAGE OF INVERTED TROUGH AND SFC SYSTEM INTO EASTERN
WI WILL OCCUR BY LATE MONDAY NIGHT...50H TROF WILL DIG
INTO WESTERN MN BY TUE/12Z...AND THEN FINALLY MARCH THROUGH
EASTERN CWA BY EARLY WEDNESDAY MORNING. USED GFS40 FOR
ALL OF LONG TERM FORECAST CONSIDERING CURRENT EXCELLENT
HANDLING OF SNOW EVENT. BEST THETA E ADVECTION COUPLET
NOTED OVER MUCH OF CENTRAL CWA AND INTO WEST CENTRAL
WI AROUND SUN/12Z TIME PERIOD. COUPLET DEGRADES SOMEWHAT
DURING THE DAY ON SUNDAY WITH BEST THETA E ADVECTION STILL
NOTED OVER WEST CENTRAL WI. 295K ISENTROPIC ANAL INDICATES
BEST PCPN CHANCES ACROSS MUCH OF REGION LATE SAT NIGHT INTO
EARLY SUN AFTN. LUCKILY 850 TEMPS SHOULD BE WARM ENOUGH FOR
MAINLY A LIQUID PCPN EVENT THROUGH MONDAY AFTN. COULD BE A
SHORT WINDOW OF FREEZING RAIN SUN 06-12Z OVER A NARROW SWATH OF
FA 30 MILES EITHER SIDE OF A LINE FROM AXN TO ANOKA. TEMPS
ALOFT WILL PRODUCE A MAINLY LIGHT SNOW EVENT MONDAY EVENING
AND INTO TUESDAY. BEFORE THIS OCCURS HOWEVER...COULD SEE
A FEW ISOLATED THUNDERSTORMS ACROSS EXTREME SOUTHERN MN
MONDAY AFTN ASSOCIATED WITH NEAR NEGATIVE LI`S.
ANOTHER WEAK SURFACE TROF INDICATED TO SWEEP THROUGH THE
FA WED NIGHT THROUGH EARLY THU. BEST FORCING INDICATED
MAINLY OVER WEST CENTRAL WI. NOT MUCH FOR POPS AND ATMOSPHERIC
COLUMN AGAIN POINTS TO A RAIN SNOW MIX FOR THIS SHORT EVENT.
ONE GOOD NOTE FOR FORECAST CONCERNS WARMING TREND FOR AFTN
HIGHS WED-THU. LOOK FOR TEMPS RAMPING UP INTO THE UPPER 40S TO
MID 50S BOTH DAYS..WHICH IS MORE IN TUNE WITH NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 138 PM CDT THU APR 18 2013
BAND OF HEAVY SNOW SETTING UP ACROSS MN THIS AFTERNOON. SEEING
CONVECTIVE ELEMENTS COMING UP OUT OF IA INTO THE MN SNOW
BAND...WHICH FURTHER SUPPORTS THE IDEA OF HEAVY SNOW CONTINUING
THROUGH THE AFTERNOON. THE RAP HAS DONE A GREAT JOB IN HANDLING
THE EVOLUTION OF THE SNOW SO FAR...SO FOLLOWED IT CLOSELY FOR TIMING
SNOW THROUGH TERMINALS. 1/4SM TO 1SM VIS IN SNOW WILL BE COMMON
THROUGH 00Z AT ALL BUT EAU. FOR EAU...NAM CHANGES TO SNOW AT 1Z
WITH THE RAP CHANGING OVER AT 4Z. EXPECTING AMOUNTS NEAR 10 INCHES
AT RWF/STC...6 INCHES AT MSP/RNH/AXN...WITH LESS THAN 3 INCHES AT
EAU. FOR THE IMPROVEMENT...MAY BE A LITTLE SLOW IN IMPROVING
CONDITION TONIGHT/FRI MORNING...BUT LATER TAFS CAN IMPROVE THAT
TIMING. FOR WINDS...DID BUMP THEM DOWN THROUGH THE AFTERNOON AS
HEAVY SNOW APPEARS TO BE DAMPENING WINDS SOME...WITH SPEEDS
EXPECTED TO INCREASE TONIGHT AS SNOW LETS UP.
KMSP...
GIVEN RECENT RADAR TRENDS AND RAP FORECASTS...CONFIDENCE HIGH IN
HEAVY SNOW IMPACTING MSP BETWEEN 20Z AND 03Z...WITH A GRADUAL
DECREASE IN INTENSITY BETWEEN 03Z AND 06Z. HAVE INCREASED EXPECTED
SNOWFALL AMOUNTS AS A RESULT UP INTO THE 6 INCH RANGE. CONFIDENCE
DECREASES SOME WITH RATE OF IMPROVEMENT TONIGHT...THOUGH
CONFIDENCE IS HIGH IN CIGS REMAINING BELOW 1700 FT. DURING THE
MORNING INTO THE AFTERNOON...WILL SEE CIGS IMPROVE ABOVE 1700 FT.
FOR WINDS...DIMINISHED SPEEDS COMPARED TO LAMP WHILE HEAVY SNOW IS
FALLING...BUT INCREASED SPEEDS CLOSER TO LAMP GUIDANCE AS SNOW
BEGINS TO DIMINISH TONIGHT.
/OUTLOOK FOR KMSP/
SAT...VFR WITH MVFR AND -RA POSSIBLE LATE. WINDS SE AT 10G15KTS.
SUN...MVFR WITH IFR AND -RA POSSIBLE. WINDS S AT 10G15KTS.
MON...MVFR OR LOWER WITH -RA POSSIBLE. WINDS BCMG NNW 10G20KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 10 AM CDT FRIDAY FOR MNZ041>045-
047>070-073>076-082-083-091.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT FRIDAY FOR MNZ077-078-084-
085-092.
WI...WINTER STORM WARNING UNTIL 10 AM CDT FRIDAY FOR WIZ014.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT FRIDAY FOR WIZ015-016-
023>025.
&&
$$
SHORT TERM...MPG
LONG TERM...AJZ
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1215 AM CDT Wed Apr 17 2013
.UPDATE...
Issued at 840 PM CDT TUE APR 16 2013
00Z raobs from surrounding sites as well as sites to the south reveal
a very stout elevated mixed layer (EML) that will be difficult to
overcome. Lack of radar returns within a 300 mile radius confirms
this. Have already lowered evening PoPs as a result and am
considering lowering them after midnight as well. Thinking scattered
coverage vs widespread as current PoPs would indicate. Would like to
get a look at the 00Z NAM before committing to lowering the PoPs. Do
believe the 00z RAP looks reasonable with best chances for convection
over the northern /12 of CWA where cap should be weaker.
&&
.SHORT TERM...(This Evening through Wednesday)
Issued at 425 PM CDT TUE APR 16 2013
Current water vapor imagery and H5 heights indicate a vigorous
trough moving from eastern Ontario into Quebec with associated cold
front draped across the eastern Great Lakes region and into the Ohio
River Valley. Southwest flow aloft will continue over the central
portion of the country as an upper level ridge strengthens in
response to a relatively broad trough continuing to dig into the
inter-mountain west and Great Basin. At the surface...stationary/warm
front extends from central Texas to south-central Oklahoma and on up
into northwest Arkansas and southeast Missouri. Temperatures in the
upper 70s to low 80s made for a nice afternoon south of the this
front with temperatures in the 40s and 50s just north of the frontal
boundary.
Current elevated front will be the focus for convection tonight and
through tomorrow night. Upper level diffluence will increase as the
western trough digs into the Great Basin. With moisture continuing to
pool along and south of the warm front, and steepening lapse rates,
expect elevated scattered thunderstorms to develop near the front
late this evening. Much of the overnight activity will remain along
the 700mb thermal ridge as low-level jet increases across the south-
central plains. Primary severe threat looks to be large hail overnight
tonight and early tomorrow morning as instability increases and bulk
shear values increase to near 50kts. Both the GFS and EC have at
least 500 J/kg of CAPE across much of the CWA and increasing to
around 1500 J/kg by tomorrow afternoon.
Thunderstorm coverage will increase through tomorrow morning and
another chance for severe weather by tomorrow afternoon and evening.
Given decent moisture profiles and the chance for heavy rainfall in
many locations, have decided to issue a flash flood watch
encompassing the entire CWA. The flash flood watch will extend from
noon tomorrow through Thursday. Felt that the main threat would not
be recognized until tomorrow, especially north of I-70 where flash
flood guidance has suggested that higher rainfall amounts will be
needed to achieve saturation and then runoff. Storm relative flow
aligned generally parallel to the surface front will allow for
training of thunderstorm and areas receiving excessive rainfall
amounts.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 425 PM CDT TUE APR 16 2013
Wednesday Night...severe weather may be ongoing as we transit into
the evening and overnight hours of Wednesday. Warm sector showers
and thunderstorm activity will last into the evening hours of
Wednesday before a cold front sweeps from west to east across the
forecast region early late Wednesday night through the afternoon
hours of Thursday. There will be a ongoing threat of severe weather,
though as the evening progresses the instability fueling the
potentially severe storms will be waining taking the threat for
severe weather with it. However, the potential for large hail,
damaging winds and isolated tornadoes will persist into the early
evening hours of Wednesday. As the front moves through the threat
will transit to hail and damaging winds for the late night hours,
though with precipitable water values of 1.5 inches expected and
winds running parallel to the advancing cold front, heavy rain and
flooding will be a persistent concern.
Thursday...severe weather threat should come to an end by the early
morning hours, if the waining instability hasn`t already brought the
threat to an end Wednesday night. However, rain on the backside of
the front may persist long enough to exacerbate the already wet
conditions, which could keep the flooding threat going through much
of the daylight hours. Will leave it to later shifts to perhaps
cancel the Flash Flood Watch early if need be. Otherwise, with the
cold air on the back side of this system, have included a brief
mention of rain and snow early Friday morning, though no
accumulations are expected even if it where all snow.
With the cold temperatures once again sweeping across the region
behind the cold front, expect readings to be suppressed below normal
through the weekend and into next work week, when another reinforcing
shot of cold air will sweep into the Plains States...again.
Otherwise, a shortwave trough in the northwest flow late in the
weekend may bring more showers back to the region, first as it lifts
a modest warm front into Iowa Sunday, before the reinforcing shot of
cold air arrives possibly Monday or Tuesday. This will keep the
threat of rain across the region from Sunday afternoon through
Tuesday, with below normal temperatures.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday Night)
Issued at 1210 AM CDT WED APR 17 2013
Scattered elevated showers now heading towards the terminals and
expect to see this area increase in coverage as it spreads across
northern MO overnight. Thunder chances may be more isolated or widely
scattered but increase as sunrise approaches. Will likely see
several periods of thunderstorms during the during this forecast
period with timing being a problem due to the activity being elevated
and not tied to any one boundary.
MVFR ceilings top start off but they will gradually lower overnight
as the depth of the moisture deepens. MVFR fog also expected to form
as the showers become more widespread and continuous on Wednesday.
Brisk easterly winds until a warm front surges north late in the
afternoon. This should also allow ceilings to improve some, but still
remain MVFR. A cold front will sweep through towards the end of the
forecast with a line of thunderstorms accompanying it. Ceilings are
also expected to drop to IFR in the post frontal airmass.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH from Noon CDT today through Thursday evening
FOR KSZ025-057-060-102>105.
MO...FLASH FLOOD WATCH from Noon CDT today through Thursday evening
FOR MOZ001>008-011>017-020>025-028>033-037>040-043>046-053-
054.
&&
$$
UPDATE...MJ
SHORT TERM...PMM
LONG TERM...Cutter
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1213 AM CDT WED APR 17 2013
UPDATE TO AVIATION
.UPDATE...
ISSUED AT 951 PM CDT TUE APR 16 2013
FORECAST UPDATED TO ACCOUNT FOR HOURLY TRENDS PERTAINING TO THE
PESKY FRONT THAT IS LINGERING ABOUT THE AREA. THERE CONTINUES TO
BE A SIGNIFICANT TEMPERATURE AND MOISTURE DIFFERENCE ACROSS THE
BOUNDARY AND FURTHER REFINEMENTS ARE LIKELY AS THE NIGHT PROGRESSES.
OBSERVATIONS FROM THIS EVENING SUGGEST THAT MUCH OF THE REGION
WILL REMAIN CAPPED INTO THE OVERNIGHT HOURS. PAST FEW VERSIONS OF
THE RAP WEAKEN THE CAP OF AN ELEVATED PARCEL (AROUND 875 TO 850
MB) IN THE 08Z TO 10Z RANGE ACROSS FAR NORTHWEST PORTIONS OF THE
OUTLOOK AREA. EVEN STILL...THE 850MB FRONT APPEARS TO BE SETTING
UP ACROSS NORTHERN PORTIONS OF KS/MO. WILL NEED TO MONITOR ANY
CONVECTION DEVELOPING IN CENTRAL/WESTERN KANSAS AND THIS MAY CLIP
AREA ALONG/NORTHWEST OF A LINE FROM PITTSBURG KS TO THE LAKE OF
THE OZARKS REGION. PREVIOUS FORECAST UPDATE SHUNTED POPS TO THIS
AREA AND WILL TWEAK AS NECESSARY. WITH AROUND 1500 J/KG OF MUCAPE
POSSIBLE OVERNIGHT...ANY STORMS THAT ARE ABLE TO DEVELOP/MOVE INTO
THE AREA (WHICH WOULD BE ELEVATED IN NATURE) COULD POSE A
MARGINALLY SEVERE HAIL RISK.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 644 PM CDT TUE APR 16 2013
A PRETTY INCREDIBLE TEMPERATURE GRADIENT EXISTED OVER THE OZARKS
THIS EVENING...AS A STALLED OUT FRONTAL SYSTEM WAS POSITIONED FROM
TABLE ROCK LAKE UP TO WINONA.
IN CENTRAL MISSOURI...TEMPERATURES WERE IN THE 40S...WHILE MIDDLE
70S WERE COMMON IN PLACES NEAR THE ARKANSAS STATE LINE.
WE MADE SOME ADJUSTMENTS REGARDING PRECIPITATION CHANCES. WE TOOK
OUT POPS FOR LOCATIONS SOUTH OF THE WARM FRONT...AS THIS AIRMASS
REMAINS INHIBITED. WITH NO FORCING MECHANISM TO TRIGGER CONVECTION
WITHIN THE WARM SECTOR...THESE AREAS SHOULD REMAIN DRY THROUGH
TONIGHT.
SHOWERS AND MAYBE A FEW THUNDERSTORMS ARE POSSIBLE NORTH OF
INTERSTATE 44 CORRIDOR. LAST NIGHT...THE CONVECTION WAS POSITIONED
CLOSELY WITH THE 850MB FRONT...WHICH IS UP ACROSS WEST CENTRAL AND
CENTRAL MISSOURI TONIGHT. THESE LOCATIONS WILL EXPERIENCE THE
BETTER CHANCES FOR RAIN...OTHERWISE...MOST LOCATIONS WILL REMAIN
DRY TONIGHT.
THE FRONT SHOULD BEGIN TO LIFT NORTHWARD THROUGH THE WEDNESDAY
MORNING HOURS. THIS WILL CAUSE TEMPERATURES ACROSS MOST OF THE CWA
TO WARM INTO THE 70S AND 80S.
THUNDERSTORMS WILL BE POSSIBLE...PARTICULARLY DURING THE AFTERNOON
AND EVENING HOURS...WITH SOME OF THE THESE STORMS BECOMING SEVERE.
CRAMER
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 228 PM CDT TUE APR 16 2013
THE CONVECTION WILL LIKELY FORM INTO A LINEAR MCS DURING THE
EVENING WITH THE MAIN RISK SHIFTING TO STRAIGHT LINE WIND DAMAGE.
HOWEVER WITH STRONG LOW LEVEL SHEAR PERSISTING THROUGH THE
NIGHT...CAN NOT RULE OUT A FEW QLCS TORNADOES WITHIN THE LINE. THE
FRONT (SIMILAR TO LAST WEEKS SYSTEM) WILL ONLY SLOWLY MAKE
PROGRESS INTO THE CWA BY THURSDAY MORNING WITH THE UPPER LEVEL JET
STREAK LIKELY AIDING IN DEVELOPING LOW PRESSURE ALONG THE FRONTAL
BOUNDARY THROUGH THE MORNING HOURS THURSDAY. THE EASTERN OZARKS
WILL LIKELY HAVE THE BEST CHANCE OF SEEING REDEVELOPMENT OF SEVERE
STORMS DURING THE AFTERNOON/EVENING ON THURSDAY BEFORE THE FRONT
PUSHES EAST OF THE AREA.
COLDER AIR WILL PUSH IN (LIKE LAST WEEK) BEHIND THE FRONT WITH
TEMPERATURES DROPPING INTO THE LOW TO MID 30S OVER THE WESTERN CWA
THURSDAY NIGHT AND MUCH OF THE AREA FRIDAY NIGHT. WILL NEED TO
MONITOR FOR POTENTIAL OF FROST/FREEZE HEADLINES.
SHOULD SEE A MODERATING TEMPERATURE TREND OVER THE WEEKEND WITH
GENERALLY DRY CONDITIONS...HOWEVER UNSETTLED CONDITIONS APPEAR
LIKELY FOR THE FIRST HALF OF NEXT WEEK AS AN UPPER LEVEL TROUGH
BEGINS TO DEVELOP IN THE CENTRAL U.S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1213 AM CDT WED APR 17 2013
EXTRAORDINARY CHALLENGING FORECAST FOR THE NEXT 24 HOURS. SURFACE
COLD FRONT HAS ONCE AGAIN MOVED SOUTH OF THE AREA. THE BEHAVIOR OF
THIS FRONT IS ONE OF THE MORE CRUCIAL ISSUES OF THE FORECAST AS IT
WILL DICTATE HOW CURRENT CIGS BEHAVE AND WHETHER OR NOT SHRA/TSRA
WILL DEVELOP DURING THE DAY WEDNESDAY. HAVE GENERALLY FOLLOWED A
CONSENSUS OF THE SHORT RANGE...MESOSCALE MODELS THAT SLOWLY LIFT
THE FRONT BACK NORTHWARD THROUGH THE AREA OVER THE NEXT 12 HOURS.
IFR CIGS AT JLN/SGF SHOULD TENUOUSLY HOLD...THOUGH IT IS WORTH
NOTING THAT CLEARING IS LITERALLY JUST MILES TO THE SOUTH OF THE
AERODROMES. BBG SHOULD REMAIN VFR AS A MID LEVEL DECK OVERSPREADS
THE AREA IN THE NEXT FEW HOURS. SCATTERED THUNDERSTORMS WILL BE
POSSIBLE ALONG THE WARM FRONT WEDNESDAY MORNING INTO THE EARLY
AFTERNOON HOURS. CONFIDENCE IN OCCURRENCE AT BBG/SGF IS TOO LOW TO
PUT MORE THAN VCTS IN...CONFIDENCE IN ACTIVITY AFFECTING JLN IS
HIGHER AND HAVE USED A TEMPO FOR THE LATE MORNING/EARLY AFTERNOON
HOURS. ONCE THE WARM FRONT LIFTS NORTH OF THE REGION...THE
ATMOSPHERE SHOULD BE CAPPED AND HAVE KEPT ANY MENTION OF THUNDER
OUT. CIGS SHOULD LIFT TO LOW END VFR WITH GUSTY SOUTHERLY WINDS
DEVELOPING THROUGH THE DAY WEDNESDAY. LOW LEVEL WIND SHEAR WILL BE
AN ISSUE BOTH THIS MORNING AND AGAIN TONIGHT.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH FROM NOON CDT TODAY THROUGH LATE THURSDAY
NIGHT FOR MOZ055>058-066>071-077>081-088>091-093-094-101-
102.
KS...FLASH FLOOD WATCH FROM NOON CDT TODAY THROUGH LATE THURSDAY
NIGHT FOR KSZ073-097-101.
&&
$$
UPDATE...GAGAN
SHORT TERM...CRAMER
LONG TERM...LINDENBERG
AVIATION...GAGAN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
339 PM CDT THU APR 18 2013
...WE WRAP UP THIS WINTRY DAY WITH A TEMPORARY REPRIEVE HEADING
INTO THE WEEKEND WITH ANOTHER 1-2 DAY COLD BLAST ON THE WAY EARLY
NEXT WEEK. THEN SPRING WARMTH RETURNS TO END THE MONTH...
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 339 PM CDT THU APR 18 2013
MORNING UPPER AIR ANALYSIS INDICATES A LONGWAVE TROUGH EXTENDING
FROM SOUTH CENTRAL CANADA INTO THE PLAINS...WITH RIDGING OVER THE
EASTERN AND WESTERN CONUS. MID AND UPPER LEVEL JET ENERGY EXTENDS
SOUTH/SOUTHEAST ACROSS THE WESTERN CONUS...EAST ACROSS THE
SOUTHWESTERN CONUS AND SOUTHERN PLAINS...AND THEN NORTHEAST ACROSS
THE PLAINS AND UPPER MISSISSIPPI VALLEY. WATER VAPOR IMAGERY
INDICATES PLENTY OF MID LEVEL MOISTURE EXTENDING FROM THE SOUTHERN
PLAINS INTO THE OHIO RIVER VALLEY. A MID LEVEL DRY INTRUSION IS
EVIDENT FROM WEST TEXAS INTO EASTERN KANSAS AND PORTIONS OF MISSOURI
AND IOWA. THERE ALSO APPEARS TO BE AN AREA OF ENHANCED
VORTICITY...EMBEDDED WITHIN THE LONGWAVE TROUGH...OVER EASTERN
NEBRASKA. FINALLY...AN AXIS OF MID LEVEL DEFORMATION IS APPARENT
EXTENDING FROM THE UPPER MISSISSIPPI VALLEY...SOUTHWEST INTO THE
CENTRAL PLAINS. AT THE SURFACE AN AREA OF LOW BAROMETRIC PRESSURE IS
NOTED OVER EASTERN IOWA...WITH A COLD FRONT EXTENDING
SOUTH/SOUTHWEST ACROSS THE MISSISSIPPI VALLEY. THE LOW LEVEL WIND
FIELD ACROSS OUR AREA REMAINS FROM THE NORTHWEST AS A RESULT.
THE AFOREMENTIONED AXIS OF MID LEVEL DEFORMATION CONTINUES TO
PRESENT LIGHT SNOW TO PORTIONS OF EASTERN NEBRASKA THIS
AFTERNOON...BUT THIS ACTIVITY HAS CLEARED OUR AREA TO THE EAST FOR
THE MOST PART AND LITTLE IN THE WAY OF SNOWFALL IS BEING OBSERVED
ACROSS OUR AREA. IN ADDITION...A STRONG LOW LEVEL PRESSURE GRADIENT
CONTINUES TO PROMOTE A STRONG LOW LEVEL WIND FIELD ACROSS OUR AREA
THIS AFTERNOON. GUIDANCE FROM THE NAM...OPERATIONAL
GFS...EC...SREF-MEAN AND RAP HOWEVER ALL SUGGEST THE LOW LEVEL PRESSURE
GRADIENT WILL WEAKEN LATE THIS AFTERNOON INTO THIS EVENING...THUS
RESULTING IN DECREASING WIND SPEEDS AT THE SURFACE. GIVEN ALL
THIS...IMPROVING CONDITIONS SHOULD BE OBSERVED ACROSS THE AREA
THROUGH THE REST OF THIS AFTERNOON AND THIS EVENING AND AS A
RESULT...THE REMAINDER OF THE WINTER WEATHER ADVISORY HAS BEEN
CANCELLED.
AN OVERALL LACK IN KINEMATIC FORCING IS EXPECTED THROUGH AT LEAST
MIDDAY SATURDAY AND AS A RESULT...DRY CONDITIONS ARE EXPECTED THROUGH 18Z
SATURDAY. BY SATURDAY AFTERNOON HOWEVER...AN ~80KT MID LEVEL JET
STREAK IS EXPECTED TO MOVE ACROSS PORTIONS OF THE PLAINS AND
MISSOURI RIVER VALLEY. THE RIGHT-REAR QUADRANT OF THIS STREAK IS
EXPECTED TO SET UP SHOP OVER NORTHEASTERN PORTIONS OF OUR CWA...THUS
POTENTIALLY PROMOTING ENOUGH OF A THERMALLY-DIRECT CIRCULATION FOR
PRECIPITATION PRODUCTION. IN ADDITION TO THE SYNOPTIC-SCALE
LIFT...FORECAST PROXIMITY SOUNDINGS FROM ACROSS OUR AREA...PER THE
NAM AND OPERATIONAL GFS...SUGGEST STEEP LOW LEVEL LAPSE RATES DURING
THE AFTERNOON HOUR MAY PROMOTE UP TO 100J/KG OF POTENTIAL
INSTABILITY WITH MINIMAL CIN. ALTHOUGH LOWER TROPOSPHERIC MOISTURE
IS NOT EXPECTED TO BE ALL THAT GREAT DURING THE DAY SATURDAY...THERE
MAY BE JUST ENOUGH FORCING FOR A FEW SPRINKLES TO BE REALIZED AT THE
SURFACE. GIVEN ALL THIS...WENT AHEAD WITH SPRINKLES ACROSS ROUGHLY
THE NORTHEASTERN HALF OF OUR CWA STARTING 18Z SATURDAY.
CLEARING SKIES AND WEAK SURFACE RIDGING SHOULD PROVIDE A COLD NIGHT
ACROSS THE AREA TONIGHT...WITH LOW TEMPERATURES IN THE LOW TO MID
20S FORECAST FOR MOST LOCATIONS. PLENTY OF DIABATIC HEATING...ALONG
WITH A STRONG AND PERSISTENT DOWN-SLOPING LOW LEVEL WIND
FIELD...SHOULD PROVIDE A WARMER DAY ON SATURDAY...WITH AFTERNOON
HIGH TEMPERATURES IN THE 50S FORECAST FOR MOST LOCATIONS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 339 PM CDT THU APR 18 2013
PATTERN: OTHER THAN A BRIEF BREAK LAST WEEKEND WE/VE BEEN IN A COLD
WET PATTERN SINCE APR 9TH. WE/LL SEE A REPEAT OF THIS REPRIEVE...
IMPROVING TEMPORARILY THIS WEEKEND BEFORE THE LAST MAJOR COLD PLUNGE
IN THIS CURRENT PATTERN. THEREAFTER ENSEMBLES CONTINUE TO INDICATE A
PATTERN CHANGE WITH REORIENTATION OF THE LONG-WAVE CONFIGURATION.
THE CUT-OFF LOW CURRENTLY UNDER THE N PAC REX BLOCK WILL HEAD E...
SHOVING THE E PAC RIDGE INTO THE WRN USA.
MONTHLY TEMP THUS FAR: AS OF MIDNGT GRI IS SITTING AT AN AVERAGE
TEMP OF 43.6F. THIS IS 4.6F BELOW NORMAL. THE LAST APRIL THAT WAS
THIS COLD WAS 1983...WHICH INCLUDED ALL 30 DAYS.
ALOFT: THE SHORT-WAVE /SHRTWV/ TROF OVER THE PAC NW AT 00Z/SAT WILL
MOVE THRU SAT-SAT NGT. THIS TROF WILL BEGIN CARVING OUT THE NEXT
LGWV TROF. THE NEXT MORE POTENT SHRTWV TROF DELIVERS THE CANADIAN
COLD. THIS LAST BLAST IS FORCED BY HGT RISES APPROACHING THE W
COAST. TUE LOOKS LIKE THE COLDEST DAY.
SFC: HIGH PRES HEADS E SAT WHILE LOW PRES TRACKS ACROSS SRN CANADA.
ITS POTENT COLD FRONT WILL MOVE THRU HERE SOMETIME MON. THEN CHILLY
HIGH PRES SETTLES IN TUE-WED. A REINFORCING SHOT OF BELOW NORMAL
CHILL COULD PROVIDE A GLANCING BLOW THU...BUT TEMPS WILL STILL BE
HEADING UP. THEN FRI ITS BACK TO NORMAL /60S TO NEAR 70F/.
HAZARDS: THERE COULD BE MULTIPLE THUNDER THREATS EARLY NEXT
SUN-MON. PERIOD OF NEAR ADVISORY MATERIAL WINDS. THERE IS ALSO A
VERY LOW PROBABILITY FOR MINOR ACCUMULATING SNOW FOR PARTS OF THE
FCST AREA...ESPECIALLY IF IT COINCIDES WITH NIGHTTIME HRS MON NGT.
UPCOMING PCPN OPPORTUNITIES: MULTIPLE EVENTS OF VARYING MAGNITUDE
SAT-MON. FOR NOW LOOKS LIKE THE NEXT POTENTIALLY MODERATE PCPN EVENT
IS SLATED FOR MON NGT-TUE MRNG BUT THIS IS SUBJECT TO CHANGE.
THE DAILY DETAILS...
FRI NGT: WARM FRONT DEVELOPS AND LIFTS THRU. LOSS OF FRI AFTN`S
INSTABILITY WILL BRING AN END TO THE THREAT OF SPRINKLES.
SAT: DRY FOR MOST OF THE FCST AREA. ELEVATED MIXED LAYER /EML/
ADVECTS IN AS WINDS BACK IN THE 900-700 MB LAYER. THIS WILL STABILIZE
SFC PARCELS. LOW-LVL MSTR WILL NOT BE ENTRAINED ENUF FOR MID-LVL
INSTABILITY.
THIS TROF WILL BE MUCH MORE BROAD SUN-MON VS THE ONE MOVING THRU
ATTM. SO TRYING TO PIN DOWN ANY SENSIBLE WX AND ITS IMPACTS IS
TOUGH. FOR SURE WE KNOW THE PRIMARY FORCING MECHANISM WILL BE THE
COLD FRONTAL PASSAGE /CFP/ MON MRNG. THE GFS ENSEMBLE CLUSTERING FOR
0.5" QPF IN 24 HRS OCCURS 06Z/MON-06Z/TUE...ESSENTIALLY SUN NGT THRU
MON NGT.
MSTR RETURN WILL BE A PROBLEM WITH THIS MULTI-DAY SYSTEM. THE SYSTEM
CURRENTLY AFFECTING THE ERN USA WILL SWEEP THE HIGHEST QUALITY MSTR
FAR S INTO THE GULF. SO INSTABILITY WILL BE MODEST. PRESENT
INDICATIONS ARE THAT DWPTS OF 50F WON/T ARRIVE UNTIL MON AFTN OVER
OUR FAR SE COUNTIES. EC OFFERS SBCAPE OF 500 J/KG. SO NO SVR TSTMS
ARE EXPECTED.
MON: EARLY MRNG CFP. DAILY HIGH TEMPS MIGHT OCCUR BTWN MIDNGT AND 7
AM. STRONG CAA RESULTS IN FALLING TEMPS. HOWEVER...SUGGEST USING MON
TEMPS WITH CAUTION. THERE IS UNCERTAINTY IN TIMING OF FROPA. SOME
MID-LVL INSTABILITY MAY REMAIN ABOVE THE FRONTAL SFC AND/OR AHEAD OF
THE FRONT IF ITS PASSAGE IS DELAYED.
MON-TUE: H8 TEMPS ARE FCST 2 STANDARD DEVIATIONS BELOW NORMAL! GFS
ENSEMBLE MEAN HAS -4C H8 ISOTHERM INTO N-CNTRL KS AT 12Z/TUE.
IF TUE ENDS UP CLOUDY...WE COULD BREAK THE RECORD FOR THE COLDEST
HIGH TEMP EVER OBSERVED ON APR 23RD. THIS ISN/T IN THE BAG BECAUSE
WE/RE STILL SEE DISAGREEMENT ON WHEN THE BEST CHANCE FOR PCPN FALLS.
IF IT ENDS UP TUE AS THE 00Z EC/GEM SUGGEST...HIGH TEMPS IN THE 30S
ARE PROBABLE. NOT READY TO GO THERE YET BUT IT/S ON THE TABLE.
DON/T LOSE HEART. THE NAEFS 8-14 DAY TEMP OUTLOOK /WHICH INCLUDES
ALL THE CANADIAN-GFS ENSEMBLE MEMBERS/ INDICATES NEAR NORMAL TEMPS.
HOWEVER...AFTER THU 4/25 TEMPS MAY ACTUALLY HEAD TO THE OTHER SIDE
OF THE SCALE...AVERAGING AT OR ABOVE NORMAL TO CLOSE OUT THE
MONTH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1222 PM CDT THU APR 18 2013
IFR CONDITIONS TO CONTINUE THROUGH THIS AFTERNOON AND PERHAPS THIS
EVENING...WITH VFR CONDITIONS EXPECTED THEREAFTER.
BLOWING SNOW WILL CONTINUE RESTRICTING THE VISIBILITY TO AROUND
1SM THIS AFTERNOON...AND PERHAPS INTO THIS EVENING. THE LOW LEVEL
WIND FIELD IS EXPECTED TO DIMINISH IN INTENSITY THIS EVENING THUS
ALLOWING FOR IMPROVED VISIBILITY. THE CEILING WILL VARY BETWEEN
2500FT AND 3500FT AGL THROUGH THROUGH THIS EVENING AS
WELL...BEFORE A PREVAILING VFR CEILING PRESENTS ITSELF TONIGHT
INTO TOMORROW. THE SURFACE WIND WILL REMAIN FROM THE
NORTHWEST...SUSTAINED AT AROUND 20KTS AND GUSTING NEAR 30KTS
THROUGH THIS EVENING...DECREASING TO AROUND 12KTS TONIGHT.
.CLIMATE...
ISSUED AT 339 PM CDT THU APR 18 2013
GRI AND HSI WILL SET THE RECORDS FOR THE COLDEST HIGH TEMPS EVER
RECORDED FOR THIS DATE. EXPECT THE RECORD EVENT REPORTS /RER/ TO
POST AROUND OR SHORTLY AFTER 530 PM.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...BRYANT
LONG TERM...HALBLAUB
AVIATION...BRYANT
CLIMATE...HALBLAUB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1238 PM CDT THU APR 18 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT THU APR 18 2013
THE PV1.5 ANOMALY CURRENTLY ACROSS WRN KS HAS SPAWNED ANOTHER
LOCALLY STRONG BUT NARROW BAND OF MODERATE SNOW. THIS BAND OF
SNOW WILL MOVE WITH THE ANOMALY AND THE RUC LIFTS IT NORTH
NORTHEAST VERY QUICKLY THIS MORNING. ACCUMULATING SNOWFALL COULD
BE OUT OF THE FCST BY 15Z AND HIGHEST ACCUMULATIONS...PERHAPS 4
INCHES...SHOULD FOCUS ALONG AND EAST OF HIGHWAY 281 INCLUDING
CUSTER COUNTY.
IT IS CLEAR THE DRY AIR IS WINNING OUT ON THIS SYSTEM AS THE SNOW
HAS SHUT OFF WEST OF HIGHWAY 61 ACROSS WRN NEB. THE RAP IS
SUGGESTING SOME SNOW SHOWER ACTIVITY TODAY AS THE 500 MB COLD
POOL MOVES OVERHEAD...ESPECIALLY TO THE LEE OF THE BLACK HILLS
WHERE A CONVERGENCE ZONE COULD DEVELOP. THE MODELS DO NOT FCST
THE LOCATION OF CONVERGENCE VERY WELL BUT THE RAP...GEM REG AND
NAM ARE SUGGESTING THE PANHANDLE SOUTH SOUTHEAST OF CHADRON. THE
FCST TODAY JUST BROAD BRUSHES ISOLATED SNOW SHOWERS WEST BUT
TAPERS THE SNOW OFF IN THE NORTHEAST.
THE NAM AND RAP SHOW SKIES CLEARING AROUND NIGHTFALL TONIGHT. THE
ARCTIC HIGH WILL BUILD THROUGH THE CNTL ROCKIES TONIGHT WHILE LOW
PRESSURE SWIRLS ACROSS THE UPPER MIDWEST ALLOWING FOR WINDS TO
STAY UP A BIT. THIS MIGHT HOLD LOWS NEAR 20 AND RADIATIONAL
CONDITIONS WILL BE LESS THAN IDEAL.
THE SNOW FCST IS FOR 1 TO 3 INCHES OF NEW SNOW TODAY. THIS USES
THE RUC QPF BUT REDUCES IT BY 70 PERCENT IN MOST AREAS AND
APPLIES A 10 TO 1 RATIO. THIS IS THE SAME AS REDUCING THE QPF BY
50 PERCENT AND USING A 14 TO 1 RATIO WHICH MIGHT BE CLOSER TO
REAL LIFE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 359 AM CDT THU APR 18 2013
FRIDAY WILL SEE HIGHS REBOUND BACK INTO THE 40S...NEAR 50 FOR FAR
SW NEB. HOWEVER NORTHWEST FLOW WILL BRING A DISTURBANCE ACROSS THE
NORTHERN PLAINS. MODELS SHOW SOME DECENT LOW LEVEL
SATURATION...WITH DRY AIR ALOFT. COULD SEE SOME DRIZZLE OR
SPRINKLES DURING THE DAY...HOWEVER JUST NOT ENOUGH CONFIDENCE TO
ADD YET...MAINLY DUE TO CURRENT CONDITIONS ON THE DRIER SIDE.
SATURDAY AND SUNDAY THE COUPLE MORE OF QUICK MOVING DISTURBANCES
WILL RIDE ACROSS NORTHERN/CENTRAL PLAINS. BETTER ENERGY IS TO THE
NORTH...HOWEVER WILL SEE THE SOUTHERN EDGE MOVE ACROSS THE CWA.
EXPECTING TO CONTINUE TO SEE COLD AIR ALOFT SPREAD DOWN FROM
CANADA...HOWEVER LESS MOISTURE TO WORK WITH IN THE LOWER LEVELS.
STRONGER COLD FRONT SUNDAY WITH GFS DEVELOPING SOME MARGINAL
CAPE...COUPLE HUNDRED J/KG...AND BARELY NEG LI/S AHEAD OF THE
FRONT. HAVE INTRODUCED ISOLD THUNDER DURING THE DAY...WHICH MAY
LINGER INTO THE EVENING DEPENDING ON EXACT TIMING OF THE FRONT
AND MOISTURE.
MONDAY AND TUESDAY ARE EXPECTED TO BE ANOTHER WELL BELOW NORMAL
COUPLE OF DAYS. GFS CAME IN COOLER...WHICH IS CLOSER TO THE
COOLER EC. HIGHS LIKELY IN THE 40S...WHICH WOULD NORMALLY BE A
STRETCH TO GO SO FAR BELOW NORMAL /NORMAL IS 60S/ THIS FAR OUT.
HOWEVER WITH THE LAST TWO SYSTEMS SHOWING HOW EASY IT IS TO
ACCOMPLISH THIS APRIL...WILL CONTINUE TO BE SOME 20 PLUS DEGREES
BELOW NORMAL FOR HIGHS. LOWS IN THE 20S SO LIGHT PRECIP IS
EXPECTED TO BE RAIN OR A MIX DURING THE DAY AND A MIX TO SNOW
OVERNIGHT.
WEDNESDAY WILL SEE THE START OF ANOTHER WARMUP AND DRY
CONDITIONS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1237 PM CDT THU APR 18 2013
UPPER LEVEL LOW PRESSURE SYSTEM RESPONSIBLE FOR THE LIGHT SNOW
CURRENTLY OVER WESTERN AND NORTH CENTRAL NEBRASKA WILL CONTINUE TO
MOVE OFF TO THE EAST. ALL SNOWFALL CHANCES AT KLBF AND KVTN
SHOULD COME TO END LATE THIS AFTERNOON. MVFR CONDITIONS MAY BE
REACHED AT TIMES...BUT OVERALL STILL EXPECTING VFR CONDITIONS TO
PREVAIL GIVEN THE LIGHT NATURE OF THE SNOWFALL. WINDS WILL REMAIN
GUSTY OUT OF THE NORTHWEST WITH GUSTS CLOSE TO 30 KTS AT TIMES
BEFORE DIMINISHING THIS EVENING. CLOUDS WILL BEGIN TO CLEAR OUT
THIS EVENING AND INTO TONIGHT WITH VFR CONDITIONS EXPECTED INTO
TOMORROW MORNING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR
NEZ006>010-026>029-038.
&&
$$
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS RALEIGH NC
240 PM EDT THU APR 18 2013
.SYNOPSIS...
HIGH PRESSURE CENTERED OFF THE NEW ENGLAND COAST WILL EXTEND DOWN
THE EAST COAST TODAY. A STRONG COLD FRONT WILL APPROACH FROM THE
WEST TONIGHT... AND CROSS THE REGION FRIDAY AFTERNOON THROUGH FRIDAY
NIGHT. COOL HIGH PRESSURE WILL BUILD IN FROM THE WEST ON SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 945 AM THURSDAY...
TODAY:
A WEAKENING MID-LEVEL SHORTWAVE UNDER THE WEST SIDE OF THE BROAD
UPPER RIDGE WILL CONTINUE TO LIFT NORTHEAST TODAY. AS OF MID MORNING
CENTRAL NORTH CAROLINA WAS UNDER A SURFACE THETA-E MINIMUM...AND
WHILE THE 12Z KGSO SOUNDING SHOWED A VERY MOIST LAYER BETWEEN ABOUT
900MB AND 650MB WITH THE LAPSE RATE GREATER THAN MOIST ADIABATIC...
DURING THE DAY BOTH THE GFS AND THE NAM FORECAST WARMING AND DRYING
IN THAT LAYER. THIS SHOULD BE ENOUGH TO CAP THE ATMOSPHERE TO DEEP
CONVECTION. THE RUC...GFS...AND THE NAM ALL SHOW NO QPF IN CENTRAL
NORTH CAROLINA THIS AFTERNOON...AND THE HRRR WRF...ASIDE FROM WHAT
APPEAR TO BE SOME SPOTTY CU...SEEMS ALSO TO BE VERY LIMITED WITH
DEEP CONVECTION. WILL KEEP CHANCES FOR PRECIPITATION BELOW SLIGHT
CHANCE THROUGH THE AFTERNOON...AND WITH THE SHORTWAVE THERE WILL BE
AREAS OF CLOUDS THAT SHOULD GRADUALLY MIX AND BECOME INCREASINGLY
SCATTERED WITH TIME. UNDER AN OVERALL PARTLY SUNNY SKY...1000-850MB
THICKNESSES SUPPORT MAXES FROM AROUND 80 TO THE LOWER 80S...IN
CONCERT WITH MOS GUIDANCE. MIXING SHOULD PROVIDE FOR SOME WIND GUSTS
IN THE UPPER TEENS KNOTS AND A FEW LOWER 20S KNOTS AT TIMES
PARTICULARLY FROM AROUND NOON THROUGH THE MIDDLE OF THE AFTERNOON.
-DJF
TONIGHT:
STRENGTHENING SOUTHERLY MOISTURE TRANSPORT WITH THE APPROACH OF THE
AMPLIFIED UPPER TROUGH AND ATTENDANT SURFACE COLD FRONT INTO THE TN
VALLEY WILL LIKELY SUPPORT WIDESPREAD LOW CLOUDS INTO THE AREA
AFTER MIDNIGHT WITH SPOTTY WAA SHOWERS OVERSPREADING THE AREA FROM
OFF THE ATLANTIC/SOUTHEAST COAST. LOWS IN THE LOWER 60S. -CBL
THE DISCUSSION ON FRIDAY`S STORMS SYSTEM WILL BE UPDATED SHORTLY...
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 240 PM THURSDAY...
A COLD FRONT AND THE ASSOCIATED LINE OF CONVECTION WILL BE EXITING
THE CWA SATURDAY MORNING...WITH MOST GUIDANCE INDICATING BY PASSAGE
BY 12Z OR SHORTLY THERE AFTER. THE POST FRONTAL AIRMASS WILL BE
DOMINATED BY A STRONG AND EXPANSIVE HIGH PRESSURE CENTER THAT WILL
BUILD ACROSS THE GREAT LAKES REGION. WITH THIS COOLER
AIRMASS...LOW LEVEL THICKNESSES TAKE A PLUNGE INTO THE 1330M
VICINITY...WHICH IS 30M BELOW NORMAL. THIS CORRELATES TO HIGHS
ABOUT 10 DEGREES BELOW NORMAL IN THE LOW TO MID 60S BOTH SATURDAY
AND SUNDAY. AS THE HIGH CONTINUES TO STRENGTHENING TO 1035MB AND
SHIFTS TOWARD NEW ENGLAND GOOD RATIONAL COOLING WILL LEAD TO LOWS IN
THE LOW TO MID 40S...WITH SOME GUIDANCE SUGGESTING UPPER 30S
POSSIBLE.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 240 PM THURSDAY...
AN EXTENDED PERIOD OF BELOW NORMAL TEMPERATURES EARLY TO MID WEEK...
A UNSEASONABLY STRONG SURFACE HIGH (1040MB) WILL SETTLE OVER
NORTHERN NEW ENGLAND BY SUNDAY AND IS EXPECTED TO RIDGE SOUTH INTO
CENTRAL NC FOR THE FIRST HALF OF THE WEEK. MEANWHILE...A PAIR OF
SHORTWAVES ARE FORECAST TO MOVE OUT OF THE WESTERN US/CANADA AND A
BROADER LONGWAVE TROUGH DEVELOPS...LEADING TO WEAK CYCLOGENESIS
ALONG THE STALLED OUT FRONTAL ZONE OFF THE COAST. THE GFS IS
QUICKEST WITH THE WEAKER LEAD SHORTWAVE...AND SHOWS A LOW DEVELOPING
BY LATE MONDAY. THE ECMWF IS SLOWER WITH THIS FEATURE...AND
ACCORDINGLY HOLDS OFF ON RAIN SPREADING INLAND UNTIL MONDAY NIGHT
AND TUESDAY. BASED MAINLY ON HPC`S PREFERENCE FOR THE ECMWF...WILL
KEEP THE PERIOD OF HIGHEST POPS ON MONDAY NIGHT AND TUESDAY. IN
EITHER CASE...A PROLONGED PERIOD OF COLD AIR DAMMING WILL BE
POSSIBLE...WITH HIGHS SEVERAL DEGREES WELL BELOW NORMAL. ALTHOUGH
CAD AIRMASSES ARE TYPICALLY EASIER TO ERODE THIS TIME OF
YEAR...GIVEN THE INITIAL STRENGTH OF THE SURFACE HIGH...A PORTION OF
THE COOL/STABLE AIRMASS COULD LINGER THROUGH WEDNESDAY...BEFORE THEN
NEXT COLD FRONT SWEEPS ACROSS THE AREA BY THURSDAY.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 125 PM THURSDAY...
24 HOUR TAF PERIOD: HIGH CONFIDENCE OF SUB-VFR CONDITIONS OVERNIGHT
THURSDAY INTO FRIDAY MORNING.
FOR THE REMAINDER OF THE DAY TODAY EXPECT SCATTERED TO BROKEN MID
LEVEL CEILINGS TO BEGIN TO ERODE LATER THIS AFTERNOON WITH SCATTERED
CUMULUS LEFT IN PLACE. SOUTH SOUTHEASTERLY WINDS WILL PREVAIL
THROUGH THE EVENING AND WILL REMAIN IN THE 5-10 KNOT RANGE GUSTING
TO 20 KNOTS. OVERNIGHT WINDS WILL REMAIN SOUTHERLY BUT MAY INCREASE
TO 10-15 KNOTS SUSTAINED ESPECIALLY AT NORTHERN AND WESTERN
TERMINALS. FURTHER SOUTH AND EAST EXPECT 5-10 KNOTS TO HOLD THROUGH
THE NIGHT. AFTER 6Z CEILINGS ARE EXPECTED TO DROP TO IFR LEVELS AND
WOULD NOT BE SURPRISED TO SEE LIFR AT TIMES. CONDITIONS SHOULD
IMPROVE A FEW HOURS AFTER SUNRISE BUT MAY VERY WELL STAY IN THE MVFR
RANGE UNTIL LATER IN THE AFTERNOON. AS SKIES BREAK OUT AND MIXING
BEGINS WINDS WILL BE NEAR 15 KNOTS GUSTING TO 20-25 KNOTS ON FRIDAY
WITH THE OCCASIONAL GUST TO 30 KNOTS POSSIBLE. WINDS WILL TAKE ON A
MORE SOUTHWESTERLY DIRECTION BY THE END OF THE TAF PERIOD.
LONG TERM: A STRONG FRONTAL SYSTEM IS EXPECTED TO CROSS THE AREA
FRIDAY NIGHT. STRONG TO POTENTIALLY SEVERE THUNDERSTORMS WILL BE
POSSIBLE WITH THIS SYSTEM. HEAVY RAIN IS ALSO EXPECTED. BEYOND
FRIDAY...INTERMITTENT PERIODS OF SUB-VFR CONDITIONS WILL BE POSSIBLE
THROUGH TUESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GIH
NEAR TERM...DJF/CBL
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 PM EDT WED APR 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND WESTWARD INTO THE CAROLINAS THROUGH
THURSDAY. A STRONG COLD FRONT WILL CROSS THE REGION FRIDAY NIGHT.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
AS OF 1120 AM WEDNESDAY...
TODAY: FORECAST CHALLENGE REMAINS THE THREAT OF SHOWERS/STORMS. A
MESO-CONVECTIVE VORTEX NEAR KMTV...PER RADAR AND VISIBLE IMAGERY
THIS MORNING...IS FORECAST BY THE THE RAP/RUC TO DRIFT SLOWLY IN WNW
FLOW ALOFT ACROSS THE NORTHEAST PIEDMONT AND NORTHERN COASTAL PLAIN
THROUGH 00Z. SHOWERS IN THE DEFORMATION ZONE TO THE NORTH OF THE
VORT CENTER ARE ALL THAT REMAIN...AND THESE WILL AFFECT AREAS
ADJACENT TO THE VA BORDER DURING THE NEXT SEVERAL HOURS. IN ADVANCE
OF THESE SHOWERS AND ASSOCIATED MID LEVEL CEILINGS - GENERALLY
ACROSS ALL BUT THE NW PIEDMONT - THE AIR MASS WILL DESTABILIZE WITH
STRONG INSOLATION AS TEMPERATURES RISE INTO THE LOWER TO MIDDLE
80S...AND BECOME PRIMED FOR SCATTERED STORM DEVELOPMENT WITH THE
APPROACH OF THE MCV. CORFIDI VECTORS INDICATE THE UPSTREAM MCS
MOVING INTO THE NORTHERN NC MOUNTAINS WILL ONLY GRAZE THE FAR
WESTERN AND SOUTHERN PIEDMONT AND/OR WEAKEN. GIVEN VERY WEAK
WINDS ALOFT... PRIMARILY ONLY A DISORGANIZED/PULSE SUB-SEVERE
CONVECTIVE MODE IS EXPECTED. HOWEVER...IF STORMS DEVELOP IN AN ARC
IN ADVANCE OF THE MCV AS THE HRRR SUGGESTS...MULTI-CELL MERGING OF
THE ASSOCIATED COLD POOLS...AND RELATIVELY STEEP LOW LEVEL LAPSE
RATES (AROUND 8 C/KM)...WOULD PROMOTE A MARGINALLY SEVERE WIND
THREAT.
AS OF 300 AM WEDNESDAY...
TONIGHT: ANY ONGOING CONVECTION SHOULD WIND DOWN WITH LOSS OF
DAYTIME HEATING WITH AREAS OF FOG AND OR STRATUS POSSIBLE. LOWS IN
THE MIDDLE TO UPPER 50S
THURSDAY AND THURSDAY NIGHT:
AS THE UPPER TROUGH PROGRESSES SLOWLY EASTWARD INTO THE PLAINS AND
UPPER MIDWEST ON THURSDAY...RIDGE ALOFT WILL SHIFT EAST AND
OFFSHORE. A NICE 15 TO 20 KT OF ONSHORE FLOW DEVELOPS WITH ANY
CONVECTION LARGELY REMAINING ALONG THE UPSLOPE REGIME IN THE
FOOTHILLS AND MOUNTAINS WITH THE RE-EMERGENCE OF A STRONG MID-LEVEL
CAP OVER THE AREA KEEPING IT DRY. HIGHS IN THE UPPER 70S TO LOWER
80S. STRENGTHENING SOUTHERLY FLOW IN ADVANCE OF THE APPROACHING COLD
FRONT WILL KEEP LOWS THURSDAY NIGHT IN THE LOWER 60S WITH AREAS OF
LOW CLOUDS/STRATUS POSSIBLE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
AS OF 310 PM WEDNESDAY...
..STORMY PERIOD ON FRIDAY AND FRIDAY NIGHT...
NWP GUIDANCE IS IN GOOD AGREEMENT ON MOVING A DEAMPLIFYING UPPER
TROUGH AND ASSOCIATED COLD FRONT ACROSS CENTRAL NC FOR THE FRIDAY
THROUGH SATURDAY PERIOD. GUIDANCE SUGGESTS THE COLD FRONT SHOULD
CROSS THE SOUTHERN APPALACHIANS AROUND OR JUST AFTER MIDDAY ON
FRIDAY AND REACH THE COASTAL PLAIN TOWARD MIDNIGHT. THE AIR MASS
AHEAD OF THE CONVECTION WILL BE CHARACTERIZED BY A MARGINALLY
UNSTABLE AIR MASS WITH CAPE VALUES OF AROUND 500-1000 J/KG. BUFR
FORECAST SOUNDINGS NOTE A CAPPING INVERSION EARLY IN THE DAY FRIDAY
WHICH ERODES BY AFTERNOON. THE STRONGEST LOW LEVEL FLOW TRANSLATES
NORTH AHEAD OF THE FRONT ACROSS WESTERN NC AND INTO THE MID ATLANTIC
BY FRIDAY EVENING. A REGION OF VERY IMPRESSIVE DEEP LAYER SHEAR
DRIVEN BY THE MID/UPPER JET THE LAGS BEHIND THE COLD FRONT. SPC HAS
MUCH OF THE REGION IN THE DAY 3 SEE TEXT AREA NOTING THE POTENTIAL
FOR SOME STRONG-SEVERE CONVECTION WITH THE MARGINAL INSTABILITY
BEING A LIMITING FACTOR. THE MOST LIKELY SCENARIO FEATURES
THICKENING CLOUD COVER ON FRIDAY WITH A BROAD LINE OF CONVECTION
INCLUDING A LEADING LINE OF DEEP CONVECTION SWEEPING ACROSS CENTRAL
NC DURING THE AFTERNOON AND OVERNIGHT. THE PRECIPITATION WILL BE
SLOW TO EXIT THE COASTAL PLAIN ON SATURDAY MORNING WITH THE DEEP
LAYER FLOW BECOMING MORE AND MORE PARALLEL TO THE FRONT...SUPPORTING
A REGION OF POST FRONTAL RAIN. WILL ADD A SMALL CHANCE POP TO THE
FORECAST IN THE EAST FOR SATURDAY. HIGH TEMPERATURES WILL RANGE IN
THE UPPER 70S TO LOWER 80S ON FRIDAY AND IN THE MID 60S ON SATURDAY.
OVERNIGHT LOWS FRIDAY NIGHT WILL RANGE IN THE UPPER 40S WEST TO MID
50S EAST. -BLAES
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 310 PM WEDNESDAY...
THE NORTHERN STREAM TROUGH DRIVING MUCH OF THE WEATHER IN THE SHORT
TERM LIFTS NORTHEAST INTO THE GREAT LAKES AND EASTERN CANADA OVER
THE WEEKEND. A DEAMPLIFIED FLOW AND A BROAD TROUGH IS LEFT IN ITS
WAKE FOR THE FIRST PART OF THE WORK WEEK BEFORE THE PATTERN BECOMES
MUCH MORE AMPLIFIED AS A STRONG TROUGH DEVELOPS OVER THE UPPER
MISSISSIPPI VALLEY.
SURFACE HIGH PRESSURE OVER THE NORTHEAST WILL RIDGE INTO THE MID
ATLANTIC/CAROLINAS FOR LATE SAT THROUGH SUNDAY NIGHT. THE SENSIBLE
WEATHER WILL FEATURE COOLER THAN NORMAL TEMPERATURES WITH HIGHS IN
THE LOWER TO MID 60S ON SUN AND LOWS IN THE LOWER TO MID 40S.
A FAIR AMOUNT OF UNCERTAINTY EXISTS WITH THE WEATHER ON MONDAY AND
TUESDAY. A STALLED FRONT OFF THE COAST BUCKLES BACK TOWARD THE COAST
IN RESPONSE TO A SHORT WAVE MOVING THROUGH THE SOUTHERN STREAM. HPC
NOTED THAT CONFIDENCE IN THE EVOLUTION OF THE FEATURE IS LOW BUT THE
PATTERN WARRANTS AT LEAST SLIGHT CHC POPS AND INCREASED CLOUD COVER
DURING THE LATE MONDAY THROUGH TUESDAY AFTERNOON PERIOD. THE
GREATEST POPS WILL REMAIN FOCUSED TOWARD THE COAST. A PERIOD OF
PARTLY TO MOSTLY CLOUDY SKIES IS EXPECTED DURING THIS PERIOD WITH A
COOL NORTHEAST BREEZE.
A PERIOD OF FAIR WEATHER IS EXPECTED TUESDAY NIGHT INTO EARLY
WEDNESDAY WITH SOME SHORT WAVE RIDING AHEAD OF THE NEXT DEVELOPING
TROUGH AND COLD FRONT THAT WILL APPROACH THE AREA LATE WEDNESDAY.
THIS WILL WARRANT THE ADDITION OF SLIGHT CHANCE/CHC POPS IN THE WEST
FOR WEDNESDAY AFTERNOON. HIGHS IN THE LOW TO MID 70S ARE EXPECTED ON
WEDNESDAY. -BLAES
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 230 PM WEDNESDAY...
MOSTLY VFR CONDITIONS ARE EXPECTED THROUGH THE 18Z TAF PERIOD...WITH
TWO EXCEPTIONS. THE FIRST WILL BE SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS THROUGH SUNSET...IN ASSOCIATION WITH THE SLOW PASSAGE
OF A MID LEVEL DISTURBANCE. THE PROBABILITY OF OCCURRENCE AT
ANY PARTICULAR TERMINAL IS RELATIVELY LOW...HOWEVER...SO SHOWERS
AND/OR STORMS HAVE BEEN INCLUDED ONLY IN THE VICINITY UNTIL THE
THREAT BECOMES MORE IMMINENT. THEREAFTER...VFR WILL RULE THROUGH
AROUND 07-09Z...AFTER WHICH TIME THERE IS A MEDIUM TO HIGH CHANCE OF
EARLY MORNING FOG AND/OR STRATUS...WITH CONFIDENCE HIGHEST AT KFAY
AND KRWI (WHERE IT HAS OCCURRED RECENT MORNINGS). WINDS WILL BE
LIGHT AND VARIABLE OUTSIDE OF ANY GUSTINESS AND WIND SHIFTS
ASSOCIATED WITH STORMS.
LOOKING AHEAD: THERE IS A HIGH CHANCE OF LIFR-IFR STRATUS
TERMINAL-WIDE FRI MORNING...FOLLOWED BY A PERIOD OF MVFR CEILINGS AS
THE MOIST LAYER RISES WITH DIURNAL HEATING THROUGH FRI AFTERNOON.
SHOWERS AND STORMS -- AND ASSOCIATED SUB-VFR CONDITIONS -- WILL
BECOME WIDESPREAD LATE FRI-FRI NIGHT...AND SOME STORMS WILL BE
STRONG TO SEVERE. IFR CONDITIONS AND RAIN THEN POSSIBLE IN
ASSOCIATION WITH A MIDDLE ATLANTIC COASTAL STORM ON MONDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS/CBL
SHORT TERM...BLAES
LONG TERM...BLAES
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
232 PM EDT WED APR 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND WESTWARD INTO THE CAROLINAS THROUGH
THURSDAY. A STRONG COLD FRONT WILL CROSS THE REGION FRIDAY NIGHT.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
AS OF 1120 AM WEDNESDAY...
TODAY: FORECAST CHALLENGE REMAINS THE THREAT OF SHOWERS/STORMS. A
MESO-CONVECTIVE VORTEX NEAR KMTV...PER RADAR AND VISIBLE IMAGERY
THIS MORNING...IS FORECAST BY THE THE RAP/RUC TO DRIFT SLOWLY IN WNW
FLOW ALOFT ACROSS THE NORTHEAST PIEDMONT AND NORTHERN COASTAL PLAIN
THROUGH 00Z. SHOWERS IN THE DEFORMATION ZONE TO THE NORTH OF THE
VORT CENTER ARE ALL THAT REMAIN...AND THESE WILL AFFECT AREAS
ADJACENT TO THE VA BORDER DURING THE NEXT SEVERAL HOURS. IN ADVANCE
OF THESE SHOWERS AND ASSOCIATED MID LEVEL CEILINGS - GENERALLY
ACROSS ALL BUT THE NW PIEDMONT - THE AIR MASS WILL DESTABILIZE WITH
STRONG INSOLATION AS TEMPERATURES RISE INTO THE LOWER TO MIDDLE
80S...AND BECOME PRIMED FOR SCATTERED STORM DEVELOPMENT WITH THE
APPROACH OF THE MCV. CORFIDI VECTORS INDICATE THE UPSTREAM MCS
MOVING INTO THE NORTHERN NC MOUNTAINS WILL ONLY GRAZE THE FAR
WESTERN AND SOUTHERN PIEDMONT AND/OR WEAKEN. GIVEN VERY WEAK
WINDS ALOFT... PRIMARILY ONLY A DISORGANIZED/PULSE SUB-SEVERE
CONVECTIVE MODE IS EXPECTED. HOWEVER...IF STORMS DEVELOP IN AN ARC
IN ADVANCE OF THE MCV AS THE HRRR SUGGESTS...MULTI-CELL MERGING OF
THE ASSOCIATED COLD POOLS...AND RELATIVELY STEEP LOW LEVEL LAPSE
RATES (AROUND 8 C/KM)...WOULD PROMOTE A MARGINALLY SEVERE WIND
THREAT.
AS OF 300 AM WEDNESDAY...
TONIGHT: ANY ONGOING CONVECTION SHOULD WIND DOWN WITH LOSS OF
DAYTIME HEATING WITH AREAS OF FOG AND OR STRATUS POSSIBLE. LOWS IN
THE MIDDLE TO UPPER 50S
THURSDAY AND THURSDAY NIGHT:
AS THE UPPER TROUGH PROGRESSES SLOWLY EASTWARD INTO THE PLAINS AND
UPPER MIDWEST ON THURSDAY...RIDGE ALOFT WILL SHIFT EAST AND
OFFSHORE. A NICE 15 TO 20 KT OF ONSHORE FLOW DEVELOPS WITH ANY
CONVECTION LARGELY REMAINING ALONG THE UPSLOPE REGIME IN THE
FOOTHILLS AND MOUNTAINS WITH THE RE-EMERGENCE OF A STRONG MID-LEVEL
CAP OVER THE AREA KEEPING IT DRY. HIGHS IN THE UPPER 70S TO LOWER
80S. STRENGTHENING SOUTHERLY FLOW IN ADVANCE OF THE APPROACHING COLD
FRONT WILL KEEP LOWS THURSDAY NIGHT IN THE LOWER 60S WITH AREAS OF
LOW CLOUDS/STRATUS POSSIBLE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
AS OF 300 AM WEDNESDAY...
A DEAMPLIFYING UPPER TROUGH WILL CONTINUE TO PUSH EAST THROUGHOUT
THE DAY ON FRIDAY...PROPELLING A TRAILING COLD FRONT THROUGH THE
REGION FRIDAY/FRIDAY NIGHT. SHOWERS AND THUNDERSTORMS WILL ACCOMPANY
THIS SYSTEM AS IT MOVES ACROSS CENTRAL NC AND THE MAIN CONCERN
CONTINUES TO BE THE POTENTIAL FOR SEVERE WEATHER. MODELS ARE IN
DECENT AGREEMENT WITH THE LINE OF SHOWERS AND THUNDERSTORMS MOVING
ACROSS CENTRAL NC FROM WEST TO EAST LATE FRIDAY AFTERNOON THROUGH
EARLY SATURDAY MORNING. AS IS COMMONLY THE CASE...PLENTY OF SHEAR
WILL BE IN PLACE...BUT THE AMOUNT OF INSTABILITY WILL BE THE MAIN
LIMITING FACTOR. MODELS CONTINUE TO PROG ONLY WEAK/MARGINAL
INSTABILITY...LIKELY DUE TO THE EXTENSIVE CLOUD COVER EXPECTED AHEAD
OF THE APPROACHING FRONT...AS WELL AS THE MOSTLY NOCTURNAL TIMING OF
THE PRECIP (THIS SECOND POINT WILL MOSTLY COME INTO PLAY ACROSS THE
EASTERN PORTIONS OF THE FORECAST AREA). THIS WILL CONTINUE TO BE
MONITORED...AS TIMING STILL COULD CHANGE. NEVERTHELESS...WILL
CONTINUE TO MENTION THE POSSIBILITY OF STRONG TO SEVERE
STORMS...WITH THE PRIMARY THREAT BEING DAMAGING WIND...IN THE HWO.
HIGHS ON FRIDAY ARE EXPECTED TO RANGE FROM THE UPPER 70S ACROSS THE
WEST TO LOW/MID 80S FURTHER EAST. OVERNIGHT LOWS ON FRIDAY NIGHT
WILL BE DEPENDENT ON THE TIMING OF THE EXITING PRECIP AND
COMMENCEMENT OF COLD AIR ADVECTION. AT THIS TIME...IT APPEARS PRECIP
SHOULD CLEAR OUT OF AT LEAST THE WESTERN PORTIONS OF THE FORECAST
AREA BEFORE DAYBREAK AND THEREFORE AM EXPECTING TEMPS TO RANGE FROM
THE UPPER 40S/LOWER 50S ACROSS THE WEST TO MID/UPPER 60S FURTHER
EAST. CONDITIONS WILL IMPROVE THROUGHOUT THE DAY ON SATURDAY AND
WITH COLD AIR ADVECTION PERSISTING...HIGHS SHOULD GENERALLY BE IN
THE MID/UPPER 60S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
BEHIND THE DEPARTING FRONT...HIGH PRESSURE WILL BUILD INTO THE
REGION...RESULTING IN COOLER AND DRIER WEATHER FOR THE WEEKEND.
THEN...THERE CONTINUES TO BE SOME UNCERTAINTY WITH RESPECT TO PRECIP
EARLY NEXT WEEK. THE FRONT IS PROGGED TO STALL NOT TOO FAR OFFSHORE
AND MODELS PROG A WAVE/INVERTED TROUGH THAT DEVELOPING ALONG IT
EARLY NEXT WEEK. BOTH THE GFS AND ECMWF INDICATE THIS SCENARIO
OCCURRING...BUT DIFFER ON THE TIMING OF SPREADING ANY PRECIP BACK
TOWARDS THE REGION. FOR NOW WILL MAINTAIN SLIGHT CHANCE
POPS...MAINLY CENTERED ACROSS THE EAST...BOTH MONDAY AND TUESDAY
(ALTHOUGH CONFIDENCE IS FAIRLY LOW). REGARDLESS...AS HIGH PRESSURE
RIDGES DOWN THE EASTERN SLOPES OF THE MOUNTAINS AND AN INVERTED
TROUGH DEVELOPS ACROSS THE WESTERN ATLANTIC...COOL AND MOIST
NORTHEASTERLY FLOW WILL PERSIST ACROSS CENTRAL NC. THIS WILL LEAD TO
A STRETCH OF BELOW NORMAL TEMPS...WITH HIGHS GENERALLY IN THE 60S
AND OVERNIGHT LOWS IN THE 40S EXPECTED THROUGH EARLY NEXT WEEK.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 230 PM WEDNESDAY...
MOSTLY VFR CONDITIONS ARE EXPECTED THROUGH THE 18Z TAF PERIOD...WITH
TWO EXCEPTIONS. THE FIRST WILL BE SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS THROUGH SUNSET...IN ASSOCIATION WITH THE SLOW PASSAGE
OF A MID LEVEL DISTURBANCE. THE PROBABILITY OF OCCURRENCE AT
ANY PARTICULAR TERMINAL IS RELATIVELY LOW...HOWEVER...SO SHOWERS
AND/OR STORMS HAVE BEEN INCLUDED ONLY IN THE VICINITY UNTIL THE
THREAT BECOMES MORE IMMINENT. THEREAFTER...VFR WILL RULE THROUGH
AROUND 07-09Z...AFTER WHICH TIME THERE IS A MEDIUM TO HIGH CHANCE OF
EARLY MORNING FOG AND/OR STRATUS...WITH CONFIDENCE HIGHEST AT KFAY
AND KRWI (WHERE IT HAS OCCURRED RECENT MORNINGS). WINDS WILL BE
LIGHT AND VARIABLE OUTSIDE OF ANY GUSTINESS AND WIND SHIFTS
ASSOCIATED WITH STORMS.
LOOKING AHEAD: THERE IS A HIGH CHANCE OF LIFR-IFR STRATUS
TERMINAL-WIDE FRI MORNING...FOLLOWED BY A PERIOD OF MVFR CEILINGS AS
THE MOIST LAYER RISES WITH DIURNAL HEATING THROUGH FRI AFTERNOON.
SHOWERS AND STORMS -- AND ASSOCIATED SUB-VFR CONDITIONS -- WILL
BECOME WIDESPREAD LATE FRI-FRI NIGHT...AND SOME STORMS WILL BE
STRONG TO SEVERE. IFR CONDITIONS AND RAIN THEN POSSIBLE IN
ASSOCIATION WITH A MIDDLE ATLANTIC COASTAL STORM ON MONDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS/CBL
SHORT TERM...KRR
LONG TERM...KRR
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1124 AM EDT WED APR 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND WESTWARD INTO THE CAROLINAS THROUGH
THURSDAY. A STRONG COLD FRONT WILL CROSS THE REGION FRIDAY NIGHT.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
AS OF 1120 AM WEDNESDAY...
TODAY: FORECAST CHALLENGE REMAINS THE THREAT OF SHOWERS/STORMS. A
MESO-CONVECTIVE VORTEX NEAR KMTV...PER RADAR AND VISIBLE IMAGERY
THIS MORNING...IS FORECAST BY THE THE RAP/RUC TO DRIFT SLOWLY IN WNW
FLOW ALOFT ACROSS THE NORTHEAST PIEDMONT AND NORTHERN COASTAL PLAIN
THROUGH 00Z. SHOWERS IN THE DEFORMATION ZONE TO THE NORTH OF THE
VORT CENTER ARE ALL THAT REMAIN...AND THESE WILL AFFECT AREAS
ADJACENT TO THE VA BORDER DURING THE NEXT SEVERAL HOURS. IN ADVANCE
OF THESE SHOWERS AND ASSOCIATED MID LEVEL CEILINGS - GENERALLY
ACROSS ALL BUT THE NW PIEDMONT - THE AIR MASS WILL DESTABILIZE WITH
STRONG INSOLATION AS TEMPERATURES RISE INTO THE LOWER TO MIDDLE
80S...AND BECOME PRIMED FOR SCATTERED STORM DEVELOPMENT WITH THE
APPROACH OF THE MCV. CORFIDI VECTORS INDICATE THE UPSTREAM MCS
MOVING INTO THE NORTHERN NC MOUNTAINS WILL ONLY GRAZE THE FAR
WESTERN AND SOUTHERN PIEDMONT AND/OR WEAKEN. GIVEN VERY WEAK
WINDS ALOFT... PRIMARILY ONLY A DISORGANIZED/PULSE SUB-SEVERE
CONVECTIVE MODE IS EXPECTED. HOWEVER...IF STORMS DEVELOP IN AN ARC
IN ADVANCE OF THE MCV AS THE HRRR SUGGESTS...MULTI-CELL MERGING OF
THE ASSOCIATED COLD POOLS...AND RELATIVELY STEEP LOW LEVEL LAPSE
RATES (AROUND 8 C/KM)...WOULD PROMOTE A MARGINALLY SEVERE WIND
THREAT.
AS OF 300 AM WEDNESDAY...
TONIGHT: ANY ONGOING CONVECTION SHOULD WIND DOWN WITH LOSS OF
DAYTIME HEATING WITH AREAS OF FOG AND OR STRATUS POSSIBLE. LOWS IN
THE MIDDLE TO UPPER 50S
THURSDAY AND THURSDAY NIGHT:
AS THE UPPER TROUGH PROGRESSES SLOWLY EASTWARD INTO THE PLAINS AND
UPPER MIDWEST ON THURSDAY...RIDGE ALOFT WILL SHIFT EAST AND
OFFSHORE. A NICE 15 TO 20 KT OF ONSHORE FLOW DEVELOPS WITH ANY
CONVECTION LARGELY REMAINING ALONG THE UPSLOPE REGIME IN THE
FOOTHILLS AND MOUNTAINS WITH THE RE-EMERGENCE OF A STRONG MID-LEVEL
CAP OVER THE AREA KEEPING IT DRY. HIGHS IN THE UPPER 70S TO LOWER
80S. STRENGTHENING SOUTHERLY FLOW IN ADVANCE OF THE APPROACHING COLD
FRONT WILL KEEP LOWS THURSDAY NIGHT IN THE LOWER 60S WITH AREAS OF
LOW CLOUDS/STRATUS POSSIBLE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
AS OF 300 AM WEDNESDAY...
A DEAMPLIFYING UPPER TROUGH WILL CONTINUE TO PUSH EAST THROUGHOUT
THE DAY ON FRIDAY...PROPELLING A TRAILING COLD FRONT THROUGH THE
REGION FRIDAY/FRIDAY NIGHT. SHOWERS AND THUNDERSTORMS WILL ACCOMPANY
THIS SYSTEM AS IT MOVES ACROSS CENTRAL NC AND THE MAIN CONCERN
CONTINUES TO BE THE POTENTIAL FOR SEVERE WEATHER. MODELS ARE IN
DECENT AGREEMENT WITH THE LINE OF SHOWERS AND THUNDERSTORMS MOVING
ACROSS CENTRAL NC FROM WEST TO EAST LATE FRIDAY AFTERNOON THROUGH
EARLY SATURDAY MORNING. AS IS COMMONLY THE CASE...PLENTY OF SHEAR
WILL BE IN PLACE...BUT THE AMOUNT OF INSTABILITY WILL BE THE MAIN
LIMITING FACTOR. MODELS CONTINUE TO PROG ONLY WEAK/MARGINAL
INSTABILITY...LIKELY DUE TO THE EXTENSIVE CLOUD COVER EXPECTED AHEAD
OF THE APPROACHING FRONT...AS WELL AS THE MOSTLY NOCTURNAL TIMING OF
THE PRECIP (THIS SECOND POINT WILL MOSTLY COME INTO PLAY ACROSS THE
EASTERN PORTIONS OF THE FORECAST AREA). THIS WILL CONTINUE TO BE
MONITORED...AS TIMING STILL COULD CHANGE. NEVERTHELESS...WILL
CONTINUE TO MENTION THE POSSIBILITY OF STRONG TO SEVERE
STORMS...WITH THE PRIMARY THREAT BEING DAMAGING WIND...IN THE HWO.
HIGHS ON FRIDAY ARE EXPECTED TO RANGE FROM THE UPPER 70S ACROSS THE
WEST TO LOW/MID 80S FURTHER EAST. OVERNIGHT LOWS ON FRIDAY NIGHT
WILL BE DEPENDENT ON THE TIMING OF THE EXITING PRECIP AND
COMMENCEMENT OF COLD AIR ADVECTION. AT THIS TIME...IT APPEARS PRECIP
SHOULD CLEAR OUT OF AT LEAST THE WESTERN PORTIONS OF THE FORECAST
AREA BEFORE DAYBREAK AND THEREFORE AM EXPECTING TEMPS TO RANGE FROM
THE UPPER 40S/LOWER 50S ACROSS THE WEST TO MID/UPPER 60S FURTHER
EAST. CONDITIONS WILL IMPROVE THROUGHOUT THE DAY ON SATURDAY AND
WITH COLD AIR ADVECTION PERSISTING...HIGHS SHOULD GENERALLY BE IN
THE MID/UPPER 60S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
BEHIND THE DEPARTING FRONT...HIGH PRESSURE WILL BUILD INTO THE
REGION...RESULTING IN COOLER AND DRIER WEATHER FOR THE WEEKEND.
THEN...THERE CONTINUES TO BE SOME UNCERTAINTY WITH RESPECT TO PRECIP
EARLY NEXT WEEK. THE FRONT IS PROGGED TO STALL NOT TOO FAR OFFSHORE
AND MODELS PROG A WAVE/INVERTED TROUGH THAT DEVELOPING ALONG IT
EARLY NEXT WEEK. BOTH THE GFS AND ECMWF INDICATE THIS SCENARIO
OCCURRING...BUT DIFFER ON THE TIMING OF SPREADING ANY PRECIP BACK
TOWARDS THE REGION. FOR NOW WILL MAINTAIN SLIGHT CHANCE
POPS...MAINLY CENTERED ACROSS THE EAST...BOTH MONDAY AND TUESDAY
(ALTHOUGH CONFIDENCE IS FAIRLY LOW). REGARDLESS...AS HIGH PRESSURE
RIDGES DOWN THE EASTERN SLOPES OF THE MOUNTAINS AND AN INVERTED
TROUGH DEVELOPS ACROSS THE WESTERN ATLANTIC...COOL AND MOIST
NORTHEASTERLY FLOW WILL PERSIST ACROSS CENTRAL NC. THIS WILL LEAD TO
A STRETCH OF BELOW NORMAL TEMPS...WITH HIGHS GENERALLY IN THE 60S
AND OVERNIGHT LOWS IN THE 40S EXPECTED THROUGH EARLY NEXT WEEK.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 730 AM WEDNESDAY...
ANY PATCHY FOG WILL QUICKLY LIFT AND DISSIPATE SHORTLY AFTER 12Z
WITH PREDOMINATELY VFR CONDITIONS INTO THE AFTERNOON BEFORE SCATTERED
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL BRING THE
THREAT FOR LOCALIZED SUB-VFR CONDITIONS IN HEAVY RAIN. CONVECTION
WILL DIMINISH AFTER SUNSET WITH AREAS OF FOG/STRATUS POSSIBLE
THURSDAY MORNING...ESPECIALLY IN AREAS THAT RECEIVE RAIN.
LOOKING AHEAD: MORNING FOG/STRATUS WILL POSE A THREAT AGAIN FRIDAY
MORNING. OTHERWISE EXPECT VFR CONDITIONS UNTIL THE ARRIVAL OF A COLD
FRONT AND PRECEDING SHOWERS AND STORMS FRI-FRI NIGHT. VFR CONDITIONS
IN ASSOCIATED WITH SURFACE HIGH PRESSURE RETURN FOR THE WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS/CBL
SHORT TERM...KRR
LONG TERM...KRR
AVIATION...CBL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
135 AM EDT WED APR 17 2013
.SYNOPSIS...
AN INCREASINGLY WARM AND MOIST SOUTHERLY FLOW WILL CONTINUE OVER THE
AREA UNTIL A COLD FRONT CROSSES THE REGION LATE FRIDAY AND FRIDAY
NIGHT. COOL HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTH THROUGH
THE WEEKEND.
&&
.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
AS OF 1040 PM TUESDAY...
MAIN FORECAST CONCERNS OVERNIGHT INTO WEDNESDAY CENTER ON TWO ITEMS:
1.) EXTENT OF FOG OVERNIGHT AND POTENTIAL FOR DENSE FOG; 2.) IF BAND
OF CONVECTION DRIFTING ESE ACROSS WV EARLY THIS EVENING WILL HAVE
ANY IMPACTS ON OUR WEATHER BY MORNING.
AREAS OF BROKEN STRATOCU EARLIER THIS EVENING HAVE GAVE WAY TO
EITHER CLEAR SKIES OR SCATTERED PATCHES OF STRATOCU. TEMPS HAVE
COOLED INTO THE 60S AREAWIDE LATE THIS EVENING WHILE SFC DEWPOINTS
HOLD IN THE MID-UPPER 50S TO NEAR 60. LIGHT S-SW WIND STILL BEING
REPORTED BY MANY SITES THOUGH SOME AWOS SITES IN THE SOUTH HAVE GONE
CALM. SINCE SKIES EXPECTED TO REMAIN MOSTLY CLEAR ACROSS THE SOUTH
AND EAST SECTIONS OF FORECAST AREA...WILL LIKELY SEE AREAS OF FOG
DEVELOP BETWEEN 3 AM - 5 AM WITH POCKETS OF DENSE FOG PROBABLE NEAR
BODIES OF WATER. DO NOT ANTICIPATE DENSE FOG BEING WIDESPREAD ENOUGH
TO REQUIRE THE ISSUANCE OF AN ADVISORY. ACROSS THE
PIEDMONT...ESPECIALLY THE NW PIEDMONT...CLOUD DEBRIS BLOW OFF FROM
CONVECTION CROSSING THE LOWER OH VALLEY AND CENTRAL APPALACHIANS
WILL LIKELY PROHIBIT FOG FORMATION OVERNIGHT. MIN TEMP FORECAST
APPEARS ON TARGET...55-60 DEGREES.
AREA OF CONVECTION CROSSING THE LOWER OH VALLEY AND CENTRAL
APPALACHIANS DRIFTING ESE WHILE INDIVIDUAL CELLS MOVING EAST.
MODELS VERIFYING POORLY WITH THIS SYSTEM THOUGH LATEST HRRR RADAR
PROJECTION NOT TOO BAD WITH ITS RENDITION AT 03Z. THE RAPID REFRESH
MODEL BRINGS SCATTERED SHOWERS CLOSE TO OUR NW COUNTIES BETWEEN
9Z-12Z. THIS MODEL MAY BE ONTO SOMETHING AS 00Z ANALYSIS DEPICTS
BEST 850MB THETA E ADVECTION ACROSS THE TN AND LOWER OH
VALLEY...EXTENDING EWD INTO VA. THIS SUGGEST A FEW SHOWERS MAY SKIRT
OUR FAR NRN COUNTIES EARLY WED. THUS HAVE INTRODUCED A
SLIGHT/SMALL CHANCE POP ACROSS THIS REGION EARLY WED.
THIS SFC FEATURE MAY END UP BEING A FOCUS FOR ADDITIONAL CONVECTIVE
DEVELOPMENT WEDNESDAY AFTERNOON. MID LEVEL LAPSE RATES PROJECTED TO
BE NEAR 7 DEG C WHILE SFC BASED CAPE CLOSE TO 1000 J/KG BY MID-LATE
AFTERNOON. WOULD NOT BE SURPRISED TO SEE SOME HAIL WITH THE STRONGER
STORMS WITH MARGINALLY SEVERE HAIL POSSIBLE. DAMAGING WIND THREAT
APPEARS WEAK AT THIS TIME. HAVE ADJUSTED SKY FORECAST AS WELL AS
EXTEND POPS A LITTLE FARTHER A SOUTH WEDNESDAY AFTERNOON AS
SCATTERED SHOWERS AND STORMS WILL LIKELY DRIFT SEWD. NOT EXPECTING
MUCH ACTIVITY TOO FAR SOUTH OF HIGHWAY 64 AS MODEL SOUNDINGS SUGGEST
MID LEVEL CAP WILL HOLD IN THIS REGION. DO NOT ADJUST MAX TEMPS BUT
IF CLOUD OR SHOWER COVERAGE MORE EXTENSIVE THAN CURRENT
THINKING...MAX TAMPS ACROSS THE NW AND FAR NORTHERN PIEDMONT MAY
NEED TO BE ADJUSTED DOWN A FEW DEGREES. -WSS
GOOD RADIATIONAL COOLING AGAIN WED NIGHT...WITH AREAS OF RADIATION
FOG...AND NEAR PERSISTENCE LOWS IN THE MIDDLE TO UPPER 50S. -MWS
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 300 PM TUESDAY...
UPPER RIDGE AXIS SHIFTS OFFSHORE AND SURFACE RIDGING WEAKENS ON
THURSDAY. PLENTY OF SUN AND SOUTHERLY FLOW WILL ALLOW HIGHS TO REACH
THE LOWER 80S..BUT LACK OF FORCING AND A LINGERING CAP ALOFT WILL
PRECLUDE CONVECTION OF SIGNIFICANCE. FLOW WILL GRADUALLY VEER AS THE
RIDGING CONTINUES TO WEAKEN OVERNIGHT AND SCATTERED SHOWERS ARE
POSSIBLE IN THE WEST WITH UPSLOPE COMPONENT AND INCREASING MOISTURE
ADVECTION. CLOUDINESS AND WARM ADVECTION WILL INHIBIT DIURNAL
TEMPERATURE CRASH AND MINS WILL BE MILD...AROUND 60.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM TUESDAY...
A STRONG COLD FRONT WILL BE APPROACHING FROM THE WEST AND MOVING
RATHER SLOWLY ACROSS THE STATE ON FRIDAY. THE PARENT LOW WILL BE
WELL TO THE NORTH AND LIFTING QUICKLY NORTHEAST. TIMING WILL BE
FAVORABLE AND TEMPERATURES WILL GET OFF TO A WARM START BUT WITH
LIMITED INSOLATION...ESPECIALLY WEST. THIS SOMEWHAT LIMITED
INSTABILITY COULD BE THE MAJOR INHIBITING FACTOR AS ELEMENTS
FAVORABLE FOR STRONGER TO SEVERE CONVECTION WILL BE FAIRLY
WELL-ALIGNED IN THE LATE DAY TO EARLY OVERNIGHT AS TO MAXIMIZE DEEP
LIFT. WILL INCREASE POPS FROM CHANCE IN THE WEST EARLY TO LIKELY IN
THE AFTERNOON...WITH LIKELY POPS MIGRATING INTO THE EAST OVERNIGHT
BEFORE TAPERING OFF BY SATURDAY MORNING. HIGHS ON FRIDAY WILL TOP
OUT IN THE MID 70S WEST TO LOWER 80S EAST. COLD AIR ADVECTION WILL
GET UNDERWAY AFTER MIDNIGHT WITH MINS FALLING TO THE UPPER 40S WEST
TO LOW AND MID 50S EAST.
HIGH PRESSURE BUILDING UP THE OHIO VALLEY WILL PROVIDE US WITH A DRY
SOMEWHAT COOLER THAN SEASONABLE WEEKEND. HIGHS SATURDAY AND SUNDAY
WILL BE IN THE 60S...SUNDAY MORNINGS LOW WILL BE IN THE 40S.
THE FRONT THAT PASSED OFFSHORE ON SATURDAY MORNING WILL BE LINGERING
ALONG THE COAST AND IS PROGGED TO RETROGRESS TOWARDS THE COAST
MONDAY WITH AN INVERTED TROF ALONG THE COAST EDGING UP AGAINST THE
COOL RIDGE. THIS WILL REINFORCE COOL AIR WITH GOOD NORTHEAST FLOW
AND POSSIBLY SOME SHOWERS ON TUESDAY. HIGHS MONDAY AND TUESDAY WILL
BE MOSTLY IN THE MID TO UPPER 60S.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 130 AM WEDNESDAY...
WHILE ITS NOT A NON-ZERO THREAT...THE POTENTIAL FOR WIDESPREAD
FOG AND/OR STRATUS DEVELOPMENT OVERNIGHT LOOKS TO BE ON THE
DECREASE...OWING TO A NOCTURNAL 30KT LOW-LEVEL JET JUST OFF THE
SURFACE PER KRAX VWP. ANOTHER FACTOR THAT WILL DETER WIDESPREAD
FOG/STRATUS DEVELOPMENT WILL BE THE INCREASE IN MID AND HIGH LEVEL
DEBRIS CLOUD COVER FROM THE NORTH/NORTHWEST AS A WEAKENING LINE OF
CONVECTION PROGRESSES EASTWARD OFF THE MOUNTAINS OF WEST VA. AS
SUCH...OUTSIDE OF PATCHY FOG AT KRWI AND KFAY...WILL HAVE
PREDOMINATELY VFR CONDITIONS THROUGH THE TAF PERIOD. HOWEVER THERE
IS CHANCE THAT SOME ISOLATED TO WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS COULD IMPACT NORTH/NORTHWESTERN TERMINALS THIS
AFTERNOON.
LOOKING AHEAD: MORNING FOG/STRATUS WILL POSE A THREAT THURSDAY
MORNING AND AGAIN FRIDAY MORNING. OTHERWISE EXPECT VFR CONDITIONS
UNTIL THE ARRIVAL OF A COLD FRONT AND PRECEDING SHOWERS AND STORMS
FRI-FRI NIGHT. VFR CONDITIONS IN ASSOCIATED WITH SURFACE HIGH
PRESSURE RETURN FOR THE WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...WSS/MWS
SHORT TERM...MLM
LONG TERM...MLM
AVIATION...CBL
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
646 PM CDT THU APR 18 2013
.UPDATE...
ISSUED AT 640 PM CDT THU APR 18 2013
PRIMARY CHANGES THIS UPDATE WILL BE TO CANCEL/EXPIRE CURRENT
ADVISORY ACROSS FAR SE FA. SNOW CONTINUES ACROSS THE FAR SE
HOWEVER WITH MINIMAL ACCUMULATIONS TODAY WITH TEMPERATURES ABOVE
FREEZING ALONG WITH IMPROVING VSBY FEEL THREAT FOR ACCUMULATING
SNOW OVER. CURRENT POPS LOOKING GOOD FOR REMAINDER OF THE EVENING
AS SYSTEM SLOWLY PUSHES EAST. NO CHANGES PLANNED TO TEMPERATURES
AT THIS POINT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 320 PM CDT THU APR 18 2013
THE PRIMARY CHALLENGE FOR THE IMMEDIATE SHORT TERM WILL BE TIMING
THE DISSIPATION OF THE SNOWFALL IN THE SOUTHEAST (WEST CENTRAL
MINNESOTA). RADAR CONTINUES TO SHOW WEAK ECHOES ROUGHLY SOUTH OF A
BAGLEY TO DETROIT LAKES TO WAHPETON LINE...WITH SOME LINGERING
LIGHT SNOW IN FAR SOUTHEASTERN RICHLAND COUNTY. HAVE USED RUC
GUIDANCE FOR QPF AND SNOWFALL CALCULATIONS IN THE REGION.
THIS EVENING...A JET STREAK THAT HAS HELPED AMPLIFY SNOWFALL OVER
SOUTHERN AND WEST CENTRAL MINNESOTA WILL MOVE OUT OF THE REGION
AND FORCING WILL WEAKEN. ISENTROPIC MODELS SHOW RISING
CONDENSATION PRESSURE DEFICITS AND NO ISENTROPIC LIFT FOR
REMAINDER OF AFTERNOON INTO THE EVENING. WHILE BOTH THE GFS AND
NAM SHOW UNSATURATED DEFICITS BY AROUND 00Z...MODELS CONTINUE TO
PRODUCE QPF THROUGH AROUND 06Z. FOR BLENDING PURPOSES WILL KEEP
LOWER POPS IN THE EXTREME SOUTHEAST THROUGH 12Z FRIDAY...BUT THINK
MOST PRECIP WILL BE OUT OF THE REGION BY MIDNIGHT.
RUC QPF VALUES SHOW A VERY TIGHT QPF GRADIENT RIGHT ALONG THE
BORDERS OF THE MINNEAPOLIS AND DULUTH COUNTY WARNING AREAS (ALONG
AND SOUTH OF A PARK RAPIDS TO PELICAN RAPIDS LINE)...WITH US ON THE
DRIER SIDE. LATEST RUC DID SURGE THE MOISTURE A BIT FURTHER
NORTH...SO WILL CONTINUE AN ADVISORY BUT IT WILL LIKELY BE IN THE
TWO TO FOUR INCH RANGE AT MOST. RECENT CALL TO GRANT COUNTY
SHERIFF INDICATES SNOW HAS PERSISTED ALL DAY BUT HAS MELTED AS IT
HIT PAVED SURFACES AND LESS THAN A HALF AN INCH ACCUMULATION ON
GRASS COVERED SURFACES. THUS PLAN TO KEEP HEADLINES AS THEY ARE...WITH A
00Z EXPIATING TIME.
WILL SEE A BRIEF PERIOD OF CLEAR SKIES IN EASTERN NORTH DAKOTA
TONIGHT...WHICH ALLOW TEMPS TO DROP INTO THE TEENS. HOWEVER MID
CLOUD WILL MOVE IN FROM SASK BY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 320 PM CDT THU APR 18 2013
THE NEXT WINTER SYSTEM WILL MOVE INTO THE REGION ON SATURDAY
AFTERNOON. A BAND OF MODERATE ISENTROPIC LIFT WILL MOVE ACROSS THE
REGION LATE SAT AND TRANSLATE ACROSS THE FORECAST AREA ON SUNDAY.
MODELS INDICATING SIGNIFICANT DIFFERENCES ON ORIENTATION OF PRECIP
AND THERMAL PROFILES...WITH THE NAM SHOWING A MUCH MORE PRONOUNCED
WARM LAYER BY ENOUGH OF A LOW LEVEL COLD LAYER FOR SOME REFREEZING
TO OCCUR. GFS IS COLDER AND SHOWS MOST PRECIP ACROSS THE SOUTH. DO
PREFER THE GFS SOLUTION AND HAVE HIGHEST POPS ACROSS SOUTHERN
ZONES. WILL GO WITH SNOW WITH SOME POSSIBLE SLEET/ICE PELLETS SAT
NIGHT AND SUN MORNING...WITH A BETTER CHANCE FOR RAIN SUN AFTN.
WILL NEED TO MONITOR UPCOMING MODELED THERMAL PROFILES TO FINE
TUNE THIS FCST PERIOD.
MODELS ARE IN DECENT AGREEMENT DEPICTING NORTHWEST FLOW ALOFT. THE
MODELS AGAIN DELAY THE UPPER RIDGE AND MUCH WARMER AIRMASS. THERE
WILL BE MINOR PRECIP CHANCES WITH THE HARD TO TIME
SHORTWAVES...BUT NOTHING MAJOR. THE CHALLENGING ASPECT WILL BE
WHEN/IF THE SNOWPACK ERODES ENOUGH THAT WE CAN START TRUSTING MOS
GUIDANCE (WHICH ASSUMES NO SNOW COVER). MIN TEMPS EARLY NEXT WEEK
ARE EXPECTED TO BE AROUND 30F...THUS REMAINING ABOVE FREEZING FOR
A LONGER DURATION DURING THE OVERNIGHT HOURS. THIS MAY BE ENOUGH
FOR AREAS WITHIN THE VALLEY TO LOSE ENOUGH SNOW COVER BY THE
MIDDLE OF NEXT WEEK ALLOWING SLIGHTLY WARMER MAX TEMPS (WITH THE
DEVILS LAKE BASIN REMAINING SNOW COVERED). THE AIRMASS WILL
UNDERGO LITTLE CHANGE THROUGH NEXT WEEK FROM WHAT IT IS NOW...AND
WHERE THERE IS SNOW COVER EXPECT MAX TEMPS INTO THE UPPER 30S OR
LOW 40S...WITH MID TO UPPER 40S WHERE SOME BLACK FIELDS START
APPEARING. NOT SURE ABOUT THE FORESTED AREAS IN MINNESOTA...AND WE
MAY BE TOO COLD FOR THIS AREA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 640 PM CDT THU APR 18 2013
VFR CONDITIONS HAVE EXPANDED ACROSS ALL TAF FORECAST POINTS AND
LIKELY TO CONTINUE OVERNIGHT. MAY STILL SEE SOME -SN NEAR BJI
HOWEVER CONDITIONS WILL CONTINUE TO SLOWLY IMPROVE AS SYSTEM
SLOWLY SHIFTS EAST.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...SPEICHER
LONG TERM...TG/SPEICHER
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
320 PM CDT THU APR 18 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 320 PM CDT THU APR 18 2013
THE PRIMARY CHALLENGE FOR THE IMMEDIATE SHORT TERM WILL BE TIMING
THE DISSIPATION OF THE SNOWFALL IN THE SOUTHEAST (WEST CENTRAL
MINNESOTA). RADAR CONTINUES TO SHOW WEAK ECHOES ROUGHLY SOUTH OF A
BAGLEY TO DETROIT LAKES TO WAHPETON LINE...WITH SOME LINGERING
LIGHT SNOW IN FAR SOUTHEASTERN RICHLAND COUNTY. HAVE USED RUC
GUIDANCE FOR QPF AND SNOWFALL CALCULATIONS IN THE REGION.
THIS EVENING...A JET STREAK THAT HAS HELPED AMPLIFY SNOWFALL OVER
SOUTHERN AND WEST CENTRAL MINNESOTA WILL MOVE OUT OF THE REGION
AND FORCING WILL WEAKEN. ISENTROPIC MODELS SHOW RISING
CONDENSATION PRESSURE DEFICITS AND NO ISENTROPIC LIFT FOR
REMAINDER OF AFTERNOON INTO THE EVENING. WHILE BOTH THE GFS AND
NAM SHOW UNSATURATED DEFICITS BY AROUND 00Z...MODELS CONTINUE TO
PRODUCE QPF THROUGH AROUND 06Z. FOR BLENDING PURPOSES WILL KEEP
LOWER POPS IN THE EXTREME SOUTHEAST THROUGH 12Z FRIDAY...BUT THINK
MOST PRECIP WILL BE OUT OF THE REGION BY MIDNIGHT.
RUC QPF VALUES SHOW A VERY TIGHT QPF GRADIENT RIGHT ALONG THE
BORDERS OF THE MINNEAPOLIS AND DULUTH COUNTY WARNING AREAS (ALONG
AND SOUTH OF A PARK RAPIDS TO PELICAN RAPIDS LINE)...WITH US ON THE
DRIER SIDE. LATEST RUC DID SURGE THE MOISTURE A BIT FURTHER
NORTH...SO WILL CONTINUE AN ADVISORY BUT IT WILL LIKELY BE IN THE
TWO TO FOUR INCH RANGE AT MOST. RECENT CALL TO GRANT COUNTY
SHERIFF INDICATES SNOW HAS PERSISTED ALL DAY BUT HAS MELTED AS IT
HIT PAVED SURFACES AND LESS THAN A HALF AN INCH ACCUMULATION ON
GRASS COVERED SURFACES. THUS PLAN TO KEEP HEADLINES AS THEY ARE...WITH A
00Z EXPIATING TIME.
WILL SEE A BRIEF PERIOD OF CLEAR SKIES IN EASTERN NORTH DAKOTA
TONIGHT...WHICH ALLOW TEMPS TO DROP INTO THE TEENS. HOWEVER MID
CLOUD WILL MOVE IN FROM SASK BY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 320 PM CDT THU APR 18 2013
THE NEXT WINTER SYSTEM WILL MOVE INTO THE REGION ON SATURDAY
AFTERNOON. A BAND OF MODERATE ISENTROPIC LIFT WILL MOVE ACROSS THE
REGION LATE SAT AND TRANSLATE ACROSS THE FORECAST AREA ON SUNDAY.
MODELS INDICATING SIGNIFICANT DIFFERENCES ON ORIENTATION OF PRECIP
AND THERMAL PROFILES...WITH THE NAM SHOWING A MUCH MORE PRONOUNCED
WARM LAYER BY ENOUGH OF A LOW LEVEL COLD LAYER FOR SOME REFREEZING
TO OCCUR. GFS IS COLDER AND SHOWS MOST PRECIP ACROSS THE SOUTH. DO
PREFER THE GFS SOLUTION AND HAVE HIGHEST POPS ACROSS SOUTHERN
ZONES. WILL GO WITH SNOW WITH SOME POSSIBLE SLEET/ICE PELLETS SAT
NIGHT AND SUN MORNING...WITH A BETTER CHANCE FOR RAIN SUN AFTN.
WILL NEED TO MONITOR UPCOMING MODELED THERMAL PROFILES TO FINE
TUNE THIS FCST PERIOD.
MODELS ARE IN DECENT AGREEMENT DEPICTING NORTHWEST FLOW ALOFT. THE
MODELS AGAIN DELAY THE UPPER RIDGE AND MUCH WARMER AIRMASS. THERE
WILL BE MINOR PRECIP CHANCES WITH THE HARD TO TIME
SHORTWAVES...BUT NOTHING MAJOR. THE CHALLENGING ASPECT WILL BE
WHEN/IF THE SNOWPACK ERODES ENOUGH THAT WE CAN START TRUSTING MOS
GUIDANCE (WHICH ASSUMES NO SNOW COVER). MIN TEMPS EARLY NEXT WEEK
ARE EXPECTED TO BE AROUND 30F...THUS REMAINING ABOVE FREEZING FOR
A LONGER DURATION DURING THE OVERNIGHT HOURS. THIS MAY BE ENOUGH
FOR AREAS WITHIN THE VALLEY TO LOSE ENOUGH SNOW COVER BY THE
MIDDLE OF NEXT WEEK ALLOWING SLIGHTLY WARMER MAX TEMPS (WITH THE
DEVILS LAKE BASIN REMAINING SNOW COVERED). THE AIRMASS WILL
UNDERGO LITTLE CHANGE THROUGH NEXT WEEK FROM WHAT IT IS NOW...AND
WHERE THERE IS SNOW COVER EXPECT MAX TEMPS INTO THE UPPER 30S OR
LOW 40S...WITH MID TO UPPER 40S WHERE SOME BLACK FIELDS START
APPEARING. NOT SURE ABOUT THE FORESTED AREAS IN MINNESOTA...AND WE
MAY BE TOO COLD FOR THIS AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 105 PM CDT THU APR 18 2013
THERE WILL BE A BATTLE BETWEEN DRY AIR TO THE NORTH AND MOIST AIR TO
THE SOUTH...WHICH CAN BE SEEN ON SATELLITE IMAGERY. KFAR AND KBJI
WILL BE THE SITES THAT WILL BE IFR/MVFR INTO THE NIGHTTIME
HOURS...WITH KBJI LIKELY IFR/MVFR INTO FRIDAY MORNING. STRONG
NORTHERLY WINDS WILL SUBSIDE A BIT OVERNIGHT...BUT REMAIN BREEZY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL 7 PM CDT THIS EVENING FOR NDZ053.
MN...WINTER WEATHER ADVISORY UNTIL 7 PM CDT THIS EVENING FOR MNZ024-
028>032-040.
&&
$$
SHORT TERM...SPEICHER
LONG TERM...TG/SPEICHER
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
340 PM CDT WED APR 17 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 340 PM CDT WED APR 17 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CONTINUING
CHANCES FOR LIGHT SNOW ACROSS THE SOUTHERN JAMES RIVER VALLEY NOW
THROUGH TONIGHT AND INTO THURSDAY.
CURRENTLY...A DYNAMIC UPPER LEVEL LONG WAVE TROUGH WAS OVER THE
ROCKIES WITH SOUTHWEST FLOW ALOFT OVER THE NORTHERN PLAINS.
MULTIPLE EMBEDDED SHORTWAVES IN THE FLOW WERE MOVING NORTHEAST
FROM THE BASE OF THE TROUGH ACROSS THE SOUTHERN ROCKIES INTO THE
CENTRAL AND NORTHERN PLAINS. AN UPPER LEVEL JET EXTENDS FROM THE
BASE OF THE TROUGH TO CENTRAL SOUTH DAKOTA INTO NORTHERN
MINNESOTA...PROVIDING THE FOCUS AREA FOR A PERSISTENT BAND OF
LIGHT TO MODERATE SNOW OVER MY SOUTHEAST SINCE EARLIER THIS
MORNING TILL NOW. WHILE SOME ACCUMULATIONS ARE OCCURRING...THIS IS
MAINLY ON GRASSY AREAS WITH ROAD SURFACES WET THANKS TO ROAD
SURFACE TEMPERATURES AT 60F OR HIGHER.
DUE IN PART TO OUR RECENT SNOWFALL...HIGH BOUNDARY LAYER MOISTURE
REMAINS ACROSS THE LOCAL REGION RESULTING IN A PERSISTENT STRATUS
DECK STILL IN PLACE OVER MOST OF WEST AND CENTRAL NORTH DAKOTA. DO
NOT SEE THIS DISSIPATING UNTIL MAYBE TOMORROW MORNING/AFTERNOON
WHEN A S/WV RIDGE MOVES INTO THE STATE HELPING TO SCOUR OUT THE
LOW CLOUDS.
WILL CONTINUE WITH THE SPS THROUGH THIS EVENING WITH SOME
ADDITIONAL LIGHT ACCUMULATIONS POSSIBLE SOUTHEAST WITH BOTH THE
NAM AND RAP BRINGING ANOTHER S/WV NORTHEAST ACROSS PORTIONS OF THE
JAMES BASIN THIS EVENING. ALREADY SEE THIS ENHANCED AREA OF
PRECIP EAST OF THE BLACK HILLS AND WEST OF PIERRE ADVECTING
NORTHEAST. WITH NIGHTFALL...ROAD SURFACE TEMPERATURES...AS THEY
DID LAST NIGHT...WILL FALL TO AROUND FREEZING...SO ICY CONDITIONS
ARE POSSIBLE AND WILL MENTION THIS WITHIN THE SPS.
SNOW CHANCES DECREASE THURSDAY MORNING/AFTERNOON ACROSS THE
SOUTHEAST AS THE UPPER JET MIGRATES EAST AND WEAK HIGH PRESSURE
BUILDS IN ACROSS CENTRAL NORTH DAKOTA. WITH THE CLOUDS SCOURING
OUT AND WITH THE S/WV RIDGE PROVIDING SOME WAA...HAVE FORECAST
HIGHS THURSDAY NEAR 40 WEST. 30S CENTRAL AND EAST WITH A MODERATE
NORTH FLOW REMAINING IN PLACE ALONG WITH A LONGER DURATION OF
CLOUDS.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 340 PM CDT WED APR 17 2013
NO SIGNIFICANT STORMS IN THE LONG TERM PERIOD...HOWEVER EXPECT AN
ACTIVE PERIOD THROUGH SUNDAY AS PERIODIC CHANCES FOR SNOW/SLEET/RAIN
OCCURS ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THIS WILL RESULT IN
A COUPLE OF INCHES OF MORE SNOW TO ACCUMULATE ESPECIALLY OVER NORTH
CENTRAL NORTH DAKOTA THROUGH SUNDAY. H5 PATTERN FOR MID TO LATE NEXT
WEEK STILL IN GOOD AGREEMENT WITH ESTABLISHING A H5 RIDGE OVER THE
NORTHERN ROCKIES WITH A GRADUAL MODERATING TREND AS DENOTED IN THE
H85 TEMPERATURES ACROSS MONTANA INTO WESTERN AND CENTRAL NORTH
DAKOTA.
BEGINNING THURSDAY NIGHT...A WEAK ALBERTA CLIPPER SYSTEM SLIDES INTO
NORTHWEST NORTH DAKOTA THURSDAY NIGHT AND INTO SOUTH CENTRAL NORTH
DAKOTA 12Z FRIDAY. SHORT RANGE MODELS SHOW A BAND OF LIGHT SNOW OR
POSSIBLY A WINTRY MIX ORIENTED NORTHWEST TO SOUTHEAST WITH UP TO
ONE INCH OF SNOW IN NORTH CENTRAL NORTH DAKOTA...FROM BOWBELLS TO
STANLEY...EAST TO MINOT AND SHERWOOD. PERHAPS A DUSTING COULD OCCUR
ELSEWHERE IN CENTRAL NORTH DAKOTA. LINGERING LIGHT SNOW CONTINUES
INTO FRIDAY MORNING WITH THE LOW EXITING FRIDAY AFTERNOON. EXPECT A
BRIEF PERIOD OF DRY WEATHER FRIDAY AFTERNOON INTO A PORTION OF
FRIDAY NIGHT.
FRIDAY NIGHT/SATURDAY/SUNDAY...SURFACE LOW PRESSURE/WARM FRONT IN
EASTERN MONTANA WILL PROGRESS EAST...RESULTING IN DECENT ISENTROPIC
ASCENT ON THE 285K-295K PRESSURE SURFACES. THIS PRODUCES HIGH
CHC/LIKELY POPS BY LATE FRIDAY NIGHT WEST...AND SPREADING INTO
CENTRAL NORTH DAKOTA SATURDAY. WARMER TEMPERATURES ALOFT WILL RESULT
IN RAIN ACROSS SOUTHWEST NORTH DAKOTA SATURDAY...WITH LIGHT SNOW
ELSEWHERE. WIDESPREAD SNOWFALL ACCUMULATIONS OF UP TO ONE INCH WILL
BE COMMON...WITH A COUPLE OF INCHES FAVORING NORTH CENTRAL NORTH
DAKOTA. ABOVE FREEZING ROAD TEMPERATURES DURING THE DAYLIGHT HOURS
SHOULD ALLOW FOR MELTING...WITH SNOWFALL ACCUMULATIONS MAINLY ON THE
GRASSY AREAS.
FOR MONDAY...A NORTHERN STREAM UPPER LOW/TROUGH FOLLOWS...AND DIGS
INTO WESTERN NORTH DAKOTA WITH A PRECIPITATION THREAT REMAINING
WEST...SOUTH...AND EAST OF THE FORECAST AREA. THIS LOW EJECTS OUT
LATE TUESDAY WITH A BUILDING H5 RIDGE DEVELOPING ALONG THE WEST
COAST. THIS RIDGE SLOWLY SIDES EAST INTO THE NORTHERN ROCKIES
WEDNESDAY THROUGH FRIDAY WITH A GRADUAL WARMUP. ABOVE AVERAGE
TEMPERATURES LIKELY IN THE WEST BY LATE NEXT WEEK. THIS SHOULD ALSO
PROMOTE A GENTLE MELT OF THE SNOWPACK UNDER A DRY WEATHER REGIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 340 PM CDT WED APR 17 2013
WIDESPREAD MVFR STRATUS WILL PERSIST TONIGHT...ALONG WITH AREAS OF
IFR CIGS. SHOULD SEE THE STRATUS START TO DISSIPATE THURSDAY
MORNING/AFTERNOON...ESPECIALLY WEST INTO NORTH CENTRAL...AS AN
AREA OF HIGH PRESSURE BUILDS INTO THE WESTERN DAKOTAS. A LINGERING
THREAT FOR LIGHT SNOW AND MVFR-IFR VIS PERSIST AT KJMS...WITH THE
CHANCES FOR LIGHT SNOW ENDING BY EARLY AFTERNOON THURSDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...NH
LONG TERM...KS
AVIATION...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1208 PM CDT WED APR 17 2013
.UPDATE...
ISSUED AT 1205 PM CDT WED APR 17 2013
ADJUSTMENTS TO POPS WERE THE MAIN CHANGES FOR THIS UPDATE...BASED
ON LATEST REGIONAL RADAR IMAGERY. NEAR TERM MODELS ARE HAVING
DIFFICULTIES TO SAY THE LEAST WITH SEVERAL SMALL-SCALE EMBEDDED
WAVES MOVING ACROSS THE REGION IN SOUTHWEST FLOW ALOFT. SURFACE
HIGH PRESSURE OVER THE REGION IS ALSO ACTING TO SUPPRESS
PRECIPITATION ACTIVITY TO SOME DEGREE. MAIN AREA OF LIGHT SNOW
REMAINS OVER MY SOUTHEAST...BUT DID SCALE BACK THERE FOR AN HOUR
OR TWO MID MORNING. ANOTHER EMBEDDED WAVE VIA THE RAP IS LIFTING
THROUGH CENTRAL SOUTH DAKOTA...AND HAS ACTED TO ENHANCE THE SNOW
BAND ONCE AGAIN THE LAST HOUR WITH LIGHT SNOW SPREADING
SLOWLY/SLIGHTLY NORTH ONCE AGAIN. WILL CONTINUE TO ADJUST POPS AS
NEEDED.
UPDATE
ISSUED AT 940 AM CDT WED APR 17 2013
INCREASED POPS TO CATEGORICAL SOUTHEAST TO ACCOUNT FOR MODERATE TO
HEAVY SNOW BAND STRETCHING FROM FAR NORTH CENTRAL SOUTH DAKOTA
THROUGH MY SOUTHEASTERN COUNTIES INTO FARGO. SNOW IS NOT
ACCUMULATING ON ROAD SURFACES...BUT HAVE HAD REPORTS OF 2 INCHES
OF WET SNOW ON GRASSY AREAS WITH 1-3 MORE EXPECTED. OPTED TO
CONTINUE WITH THE SPECIAL WEATHER STATEMENT WITH IMPACTS MINIMAL
AFTER CALLING STATE RADIO...LOCAL LAW ENFORCEMENT...AND EMERGENCY
MANAGERS. LOWERED/MODIFIED POPS ELSEWHERE QUITE A BIT WITH LITTLE
IF ANYTHING OCCURRING.
UPDATE ISSUED AT 652 AM CDT WED APR 17 2013
AREAS OF FOG HAVE DEVELOPED ACROSS SOUTHWESTERN NORTH DAKOTA THIS
MORNING. FURTHERMORE...PATCHY FOG HAS DEVELOPED ACROSS NORTH
CENTRAL NORTH DAKOTA IN THE VICINITY OF THE TURTLE MOUNTAIN
REGION. AS A RESULT...UPDATED THE FORECAST TO ADD AREAS OF FOG
SOUTHWEST AND PATCHY FOG NORTH CENTRAL UNTIL 15Z. THE REMAINING
FORECAST ELEMENTS ARE IN GOOD SHAPE. THE UPDATED GRIDDED AND TEXT
PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CDT WED APR 17 2013
MAIN FORECAST HIGHLIGHT IN THE SHORT TERM PERIOD WILL BE CHANCES
FOR LIGHT ACCUMULATING SNOWFALL SOUTH TODAY AND TONIGHT.
CURRENTLY...AN UPPER LEVEL LONG WAVE TROUGH WAS OVER THE ROCKIES
WITH SOUTHWEST FLOW ALOFT OVER THE NORTHERN PLAINS. SEVERAL
EMBEDDED SHORTWAVES IN THE FLOW WERE MOVING NORTH AND EAST FROM
THE BASE OF THE TROUGH ACROSS THE SOUTHERN ROCKIES INTO THE
CENTRAL AND NORTHERN PLAINS. AN UPPER LEVEL JET EXTENDED FROM THE
BASE OF THE TROUGH TO CENTRAL SOUTH DAKOTA AND PROVIDING UPPER
LEVEL SUPPORT FOR A LARGE AREA OF LIGHT SNOW THAT CONTINUED TO
DEVELOP FROM YESTERDAY AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE WAS CENTERED OVER COLORADO/NEW MEXICO AND HIGH PRESSURE
WAS OVER SASKATCHEWAN/ALBERTA/WRN MONTANA RESULTING IN AN
EAST/NORTHEAST SURFACE WIND FLOW ACROSS MUCH OF THE NORTHERN
PLAINS.
THE AREA OF LIGHT SNOW HAD EXPANDED INTO WESTERN NORTH
DAKOTA...AND REGIONAL RADARS INDICATE THAT EITHER LIGHT SNOW OR
VIRGA (SNOW NOT YET REACHING THE GROUND) SHOULD ALREADY HAVE
REACHED INTO NEAR BISMARCK AND JAMESTOWN. THE LARGE AREA OF LIGHT
SNOW FROM SOUTHWESTERN SD INTO NORTHEASTERN SD AND SOUTHEASTERN ND
WAS ASSOCIATED WITH ONE OF THE MORE SIGNIFICANT SHORTWAVES MOVING
NORTHEASTWARD. THIS WAVE IS FORECAST TO CONTINUE MOVING NORTHWARD
AND WEAKEN AS IT CONTINUES INTO CANADA BY AFTERNOON. THUS HAVE
RAISED CHANCES OF LIGHT SNOW THIS MORNING ACROSS SOUTHERN NORTH
DAKOTA. AFTER NOON...THERE APPEARS TO BE A PERIOD IN WHICH UPPER
LEVEL SHORTWAVE ENERGY DECREASES OVER NORTH DAKOTA (THOUGH SEVERAL
WAVES STILL MOVING NORTHWARD IN THE UPPER LEVEL FLOW TO OUR SOUTH)
AND THE UPPER LEVEL JET SHIFTS EASTWARD AND WEAKENS OVER NORTH
DAKOTA. THUS KEPT HIGHER PRECIP CHANCES SOUTH OF JAMESTOWN AND
HAVE DECREASING CHANCES NORTH AND WEST.
TONIGHT ANOTHER SIGNIFICANT SHORTWAVE MOVES NORTHWARD TOWARDS THE
JAMES RIVER VALLEY OF NORTH DAKOTA. THE UPPER LEVEL TROUGH
CONTINUES MOVING EASTWARD ACROSS THE PLAINS...REACHING THE CENTRAL
DAKOTAS BY DAYBREAK THURSDAY MORNING. THE LIGHT SNOW SHOULD TAPER
OFF QUICKLY IN THE JAMES RIVER BASING BY DAYBREAK THURSDAY.
SNOWFALL TOTALS FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT ARE
FORECAST TO RANGE FROM 2 TO 3 INCHES IN MCINTOSH/LAMOURE/DICKEY
COUNTIES...TO 1 TO 2 INCHES ALONG AND SOUTH OF INTERSTATE 94 WEST
OF THE JAMES RIVER BASIN...TO LESS THAN AN INCH FOR NORTHERN NORTH
DAKOTA. SOME LOCALES IN DICKEY COUNTY MAY SEE UP TO 4 INCHES.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 343 AM CDT WED APR 17 2013
SURFACE HIGH PRESSURE BUILDING INTO WESTERN AND CENTRAL NORTH
DAKOTA WILL GENERATE DRY CONDITIONS FOR MOST OF THE REGION
THURSDAY. PRECIPITATION CHANCES WILL TAPER OFF ACROSS THE EXTREME
SOUTHEASTERN CWA THROUGH THURSDAY AFTERNOON. DRY CONDITIONS WILL
CONTINUE THROUGH FRIDAY AS HIGH PRESSURE CRESTS ACROSS THE REGION.
FRIDAY AFTERNOON TEMPERATURES WILL INCREASE TO THE UPPER 30S AND
40S. HOWEVER...THIS IS STILL ABOUT 15 DEGREES BELOW NORMAL FOR
THIS TIME OF YEAR.
A SHORTWAVE TROUGH AND ITS ATTENDANT WARM FRONT IS PROGGED TO
ENTER WESTERN NORTH DAKOTA SATURDAY. DEPENDING ON HOW THE
THERMODYNAMIC PROFILE EVOLVES...PARTS OF WESTERN NORTH DAKOTA
COULD SEE ALL RAIN. HOWEVER...GIVEN THE MODEL SPREAD...WILL
FORECAST A CHANCE FOR A WINTRY MIX ACROSS WESTERN AND CENTRAL
NORTH DAKOTA SATURDAY. THE ATTENDANT COLD FRONT ASSOCIATED WITH
THE AFOREMENTIONED SHORTWAVE IS THEN PROGGED TO PUSH THROUGH THE
REGION LATE SATURDAY NIGHT/SUNDAY. CHANCES FOR A WINTRY MIX WILL
LINGER THROUGH THE LATE WEEKEND AS A RESULT. THE CHANCES FOR
PRECIPITATION WILL DIMINISH MONDAY AND TUESDAY AS HIGH PRESSURE
BUILDS INTO THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 652 AM CDT WED APR 17 2013
LIGHT TO MODERATE SNOW MAINLY SOUTH OF KJMS. A FEW LIGHT SNOW
SHOWERS ALSO AROUND KBIS. LITTLE IF ANYTHING ELSEWHERE AT THIS
TIME. AREAS OF MVFR CIGS AND VSBYS. EXPECT OCCASIONAL IFR AS
WELL. LIGHT SNOW SHOULD LINGER NEAR TO SOUTH OF KJMS FOR THE
ENTIRE TAF PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...JV
LONG TERM...TM
AVIATION...NH
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
407 PM EDT WED APR 17 2013
.SYNOPSIS...
A POTENT SPRING STORM SYSTEM WILL EJECT NORTHEAST THROUGH THE MID
MISSISSIPPI VALLEY TONIGHT THROUGH FRIDAY...BRINGING A WILD SWING
IN TEMPERATURE AND THE THREAT OF STRONG TO SEVERE THUNDERSTORMS.
VERY WARM CONDITIONS ON THURSDAY WITH GUSTY SOUTH WINDS WILL BE
FOLLOWED BY EVEN GUSTIER NORTHWEST WINDS AND TEMPERATURES SOME 30
DEGREES LOWER THAN THAN ON THURSDAY. IN THE WAKE OF THIS
SYSTEM...COOL CANADIAN HIGH PRESSURE WILL SETTLE INTO THE OHIO
VALLEY FOR THE WEEKEND WITH THE THREAT OF MORNING FROST AND SOME
DRY WEATHER.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
KIND OF A TRICKY NEAR TERM FORECAST. SURFACE ANALYSIS/METARS
CLEARLY SHOW A MORE SYNOPTIC SCALE WARM FRONTAL BOUNDARY LIFTING
THROUGH THE I-70 CORRIDOR RIGHT NOW WITH COOL 50S AND EASTERLY
FLOW OVER NRN OHIO/IND...AND SLY FLOW AND MILD 70S OVER SRN
OH/IND. HOWEVER...A PERSISTENT/REMNANT OUTFLOW BOUNDARY CONTINUES
TO PERCOLATE WITH CONVECTION IN A NW-SE AXIS FROM BLOOMINGTON IND
TO LOUISVILLE AND ON TO THE SOUTHEAST FROM THERE. LOCAL LAPS
ANALYSIS SHOWS THAT SURFACE BASED INSTBY HAS LEAKED NORTH OF THE
OUTFLOW BOUNDARY INTO THE TRI STATE AREA...WITH MLCAPES AROUND
1000 J/KG. HOWEVER...FLOW ATOP THE OUTFLOW BOUNDARY IS MODESTLY
WEAK FOR MID APRIL...AND SHEAR IS MARGINAL FOR ORGANIZED STORM
DEVELOPMENT /RIGHT AROUND 30KTS IN THE LOWEST 6KM/ GIVEN THE ALREADY
WEAK INSTBY. LATEST /17.12Z 4KM SPC WRF AND 17.15Z EXPERIMENTAL
3KM HRRR/ RUNS HAVE BEEN TRYING TO SUGGEST THAT ISOLD/SCT UPDRAFTS
WILL SLOWLY MOVE/DEVELOP NORTHEAST TOWARD THE TRI-STATE...MOVING
OFF THE OUTFLOW BOUNDARY BEFORE COLLAPSING SOMEWHERE IN SWRN/WRN
OH OR ERN IND. THIS SEEMS PLAUSIBLE GIVEN THE INSTBY THAT HAS
LEAKED NORTH OF THE OUTFLOW. BACKGROUND ASCENT IS VERY WEAK...THUS
FEEL ANY UPDRAFTS/STORMS WILL BE TIED CLOSELY TO THE DIURNAL
INSTBY CYCLE AND LOCALIZED CONVERGENCE NEAR THE OUTFLOW. HAVE
ALLOWED FOR A 25-30% PROBABILITY OF STORMS IN THE TRI-STATE FOR
THE NEXT 3-4 HOURS BEFORE BACKING OFF INTO LOWER PROBS FURTHER
NORTH AS THE NIGHT WEARS ON. NOT OUT OF THE REALM OF POSSIBILITIES
THAT BRIEF HAIL WOULD BE POSSIBLE WITH THE STRONGER CORES...AND
POCKET OF ELEVATED DCAPE PER SPC MESOA EVEN LENDS SUGGESTION OF A
GUSTY STORM OR TWO. CURRENT TRAJECTORY OF NON-SEVERE CORES
IMMEDIATELY WEST OF KLMK SUGGESTS THAT OWEN/CARROL COUNTIES IN A
FEW HOURS MAY HAVE SOME STRONGER STORMS TO DEAL WITH.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
FOUND MODEL AGREEMENT TO BE VERY STRONG THROUGH THIS PERIOD AND
GOING FORECAST HAD LARGELY CAPTURED THE ENTIRE FCST SCENARIO
EXTREMELY WELL...THUS CHANGES WERE REALLY FOCUSED ON DETAILS OF
WINDS/TIMING OF STORMS...AND TIGHTENING UP GRADIENTS AHEAD/BEHIND
THE EXPECTED COLD FRONT TOMORROW NIGHT.
AFTERNOON GOES WATER VAPOR IMAGERY AND RAP ANALYSIS INDICATED A
VERY DYNAMIC AND COLD LONGWAVE TROUGH /-30C AT 500MB NEAR SLC AT
12Z/ OVER THE INTERMOUNTAIN WEST WITH SEVERAL IMPRESSIVE
CONVECTIVE COMPLEXES DOWNSTREAM NEAR THE ATTENDANT FRONTAL
SYSTEMS OVER THE MID MS VALLEY. HEIGHTS HAVE BEEN RISING OVER THE
OHIO VALLEY MUCH OF THE DAY BUT THAT PROCESS WILL TURN AROUND AS A
STRONG SHORTWAVE TROUGH/UPPER JET DIGS THROUGH THE LONGWAVE TROUGH
AND EJECTS INTO THE CENTRAL PLAINS...LOWERING HEIGHTS DOWNSTREAM
OVER THE OHIO VALLEY AND ALLOWING A STRONG COLD FRONT AND LOW
PRESSURE TO FURTHER ORGANIZE AND PUSH EAST TOWARD THE AREA.
POOL OF VERY WARM /+15C AT H85/ AIR JUST TO OUR SOUTHWEST WILL
LIFT NORTHWARD AS WARM MENTIONED ABOVE CONTINUES NORTH AND DEEPER
SLY FLOW IS ATTAINED. AS DYNAMICS REALLY BEGIN TO INCREASE ON
THURSDAY MORNING...LOW LEVEL WIND FIELD AND FALLING PRESSURES TO
THE WEST WILL INDUCE A POTENT WARM ADVECTION REGIME...WITH
EFFICIENT MIXING UNDER PARTLY CLOUDY SKIES. NAM/GFS SFC PRESSURE
GRADIENT MAGNITUDES AND SOUNDING ANALYSIS VALID THURS AFTN
SUGGESTS A WINDY DAY...SUSTAINED 20 TO 30 MPH WITH GUSTS TO 40
MPH...ESPECIALLY WEST OF I-71 FROM 10 AM THROUGH THE AFTN. A
LITTLE CONCERNED FOR WIND ADVISORY CONDITIONS IN OUR FAR NORTHWEST
WHICH IS A WIND PRONE AREA AND WILL BE UNDER THE STRONGEST
INFLUENCE OF THE DEVELOPING/DEEPENING SFC-850MB CYCLONE AND
ATTENDANT LOW LEVEL JET. WILL CONTINUE TO HIGHLIGHT WIND THREAT ON
HWO. MAX TEMPS SHOULD WARM CONSIDERABLY...INTO THE 80S MOST AREAS
AND WITH A MORE SELY TRAJECTORY OVER OUR EAST...THIS IS
DOWNSLOPE/DRYING OFF THE APPALACHIAN RISE AND MAY ALLOW BETTER
DEW POINT REDUCTION/WARMING. LIKELY WILL FALL A FEW DEGREES SHORT
OF RECORDS...WHICH ARE IN THE MID/UPPER 80S.
GETS VERY INTERESTING THURSDAY AFTER ABOUT 5 PM WHEN STRONG DEEP
LAYERED ASCENT AND LOW LEVEL CONVERGENCE IN VICINITY OF FRONTAL
ZONE TO THE WEST SHOULD CONTINUE TO FOSTER DEVELOPMENT OF A VERY
LONG/STRONG SQUALL LINE. THERE/S BEEN HINTS IN THE HIGHER RES
CONVECTION ALLOWING DATA THAT A FEW DISCRETE CELLS MAY FORM IN THE
WARM SECTOR OVER OUR FAR WEST LATE AFTN/EARLY EVENING AND THAT
WOULD BE PROBLEMATIC GIVEN A WEAK MLCINH FIELD /ERODED CAP/ AND
MLCAPE AROUND 1500 J/KG AMIDST VERY STRONG FLOW /SHEAR/. RIGHT NOW
AM NOT SEEING A STRONG/CONSISTENT SIGNAL THERE...SO KEEPING RAIN
CHANCES LOW THROUGH THE DAY.
AS THE EVENING WEARS ON...ADVANCING FRONTAL ZONE /OR PREFRONTAL
TROUGH/ WILL BECOME FOCUS FOR CONTINUED ADVANCEMENT AND
DEVELOPMENT OF CONVECTIVE SQUALL LINE INTO THE WFO ILN AREA
SOMETIME BETWEEN 10 PM AND 2 AM. THINK LATEST SWODY2 FROM SPC IS
REALISTIC...THAT WFO ILN WRN CWA WILL BE A TRANSITION AREA FROM A
VERY POTENT QLCS WITH SEVERE THREAT...TO A NON-LIGHTNING PRODUCING
LINE OF RAIN OR SHOWERS LATE IN THE NIGHT INTO THE EARLY MORNING HOURS ON
FRIDAY.
CLEARLY THE HIGHEST THREATS LOCALLY OF WIND ARE IN OUR FAR WEST
BEFORE CONVECTION ENTRAINS AN INCREASINGLY HOSTILE LOW LEVEL
AIRMASS /REF ABOVE COMMENT ABOUT DRYING ON SOUTH-SELY FLOW INTO ERN
AREAS/...AND SOUNDING ANALYSIS FROM A MULTITUDE OF NWP SOURCES
INDICATES ANY SURFACE BASED/NEAR SURFACE BASED INSTBY WILL BE
MINIMAL AT BEST /100 J/KG/ WEST OF I-75. PRIOR NOCTURNAL QLCS
EVENTS HOWEVER SUGGEST MLCAPE/MUCAPE IN THESE STRONGLY FORCED
EVENTS IS OVERRATED TO A DEGREE...AND GIVEN THE EXPECTED 0-1KM
SHEAR TOWARD 50KTS...THE SHAPE/ORIENTATION OF THE LOWEST 1KM TEMP
TRACE IS VERY IMPORTANT FOR QLCS COUPLETS AND/OR DAMAGING WIND
TRANSPORT TO THE SURFACE. FCST SOUNDINGS ARE HARD TO BUY INTO
GIVEN FICKLE NATURE OF BOUNDARY LAYER RESOLUTION IN NWP...BUT
ISOTHERMAL TO WEAKLY NEGATIVE LAPSE RATES INDEED SUGGESTS WE MAY
VERY WELL HAVE A THREAT FOR DAMAGING GUSTS ESP IN THE FIRST COUPLE
OF HOURS OF THE EVENT WEST OF I-75. WITH TIME...BUOYANCY REALLY
TANKS AND EXPECT THIS CONVECTIVE SYSTEM TO STRUGGLE TO OR NOT
PRODUCE LIGHTNING OVER THE ERN 1/2 OF THE FORECAST AREA LATE IN
THE NIGHT AND FRIDAY MORNING.
ALSO...WHILE WINDS MAY DECREASE EARLY IN THE EVENING...ISALLOBARIC
COMPONENT IMMEDIATELY IN ADVANCE OF THE VERY SHARP/STRONG FRONAL
ZONE WILL PROBABLY ALLOW FOR A BRIEF/RAPID INCREASE IN SUSTAINED
AND GUSTS IMMEDIATELY AHEAD OF THE SQUALL LINE.
FOR FLOOD CONCERN...SYSTEM WILL BE PROGRESSIVE AND HAVE HIGH
CONFIDENCE IN RAIN AMOUNTS REMAINING LESS THAN AN INCH IN MOST
AREAS. HEAVIEST WEST...LIGHTEST EAST. FEEL ANY FLOODING ISSUES
WOULD BE BRIEF/NUISANCE AND TIED TO AREAS OF VERY MOIST SOILS FROM
MERCER INTO HARDIN/DELAWARE COUNTIES.
FRIDAY TO BE POLAR OPPOSITE OF THURSDAY...A 30 DEGREE TEMP CHANGE
/PERHAPS MORE IN THE WEST/ FROM DAYTIME MAX TO DAYTIME MAX...WITH
MORE GUSTY WINDS AND A RAPID END TO THE RAIN WITH DRY SLOT. THINK
WIND ADVISORY MAY BECOME LIKELY IN NORTH/WEST AT SOME POINT AS SFC
CYCLONE REACHES LOWEST PRESSURES /SUB-990MB/ OVER LAKE SUPERIOR. A
VERY CHILLY/MISERABLE DAY IN COMPARISON TO THURSDAY.
ENOUGH WEAKENING IN THE MSLP GRADIENT FRIDAY NIGHT AND POTENTIAL
CLEARING TO WARRANT INSERT OF PATCHY FROST...THOUGH FOLLOWING
NIGHT LOOKS EVEN BETTER FOR FROST.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A STRONG AREA OF HIGH PRESSURE WILL BUILD IN THE MID SECTION OF THE
COUNTRY ON SATURDAY AND NOSE INTO THE GREAT LAKES AND OHIO VALLEY
REGION BY EVENING. SOUTHEAST FLOW WILL THEN GRADUALLY TURN SOUTH
AHEAD OF THE NEXT COLD FRONT EXPECTED TO MOVE THROUGH LATE IN THE
FORECAST PERIOD.
MODELS ARE IN A WIDE RANGE FOR TIMING FOR THE TUESDAY/WEDNESDAY
SYSTEM. THE PREVIOUS FORECAST APPEARS TO HAVE THE BEST INITIAL
CONDITIONS BUT SOME NEIGHBORING OFFICES APPEAR HIGHER THAN I AM
WILLING TO GO WITH RAIN CHANCES OVERNIGHT TUESDAY. GIVEN THE LATEST
EUROPEAN WHICH SPINS THE SYSTEM UP IN THE MIDWEST ON TUESDAY...IT
HAS A MUCH SLOWER AND MORE DEVELOPED SYSTEM THAN THE GFS WHICH IS
INDICATING AN OPEN WAVE YET STRONG COLD FRONTAL PASSAGE EARLY
WEDNESDAY. WPC HAS THIS FRONT ON THE OTHER SIDE OF THE APPALACHIANS
AT THIS TIME WHICH APPEARS INCONSISTENT WITH THE REST OF THE
GUIDANCE I SEE.
UNTIL THE RAIN HITS WITH THE NEXT SYSTEM DAYS 6/7...TEMPERATURES
WILL BE ON THE INCREASE AND START FROM A COOLER 50S ON SATURDAY WITH
OVERNIGHT LOWS LIKELY NEEDING FROST HEADLINES. BY THIS TIME NEXT
WEEK AHEAD OF THE COLD FRONT...70S WILL BE FOUND AGAIN WITH
OVERNIGHT LOWS IN THE 50S. HAVE GONE WARMER THAN GUIDANCE AHEAD OF
THE NEXT SYSTEM BUT FEEL THAT THE FORECAST WILL CONTINUE TO BE
ADJUSTED UPWARD A LITTLE BIT EACH DAY.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
MAINLY MVFR CEILINGS ARE BEGINNING TO SCATTER AND SHOULD CONTINUE
TO DO SO EARLY IN THE PERIOD LEAVING VFR CONDITIONS. REMAINING
CUMULUS ARE FORECAST TO DISSIPATE BY EVENING LEAVING JUST HIGH
CLOUDS THROUGH THE REST OF THE TAF PERIOD. APPEARS THAT THERE
COULD BE ENOUGH LOW LEVEL MOISTURE FOR SOME MINOR VISIBILITY
RESTRICTIONS LATE TONIGHT THROUGH 12Z. WINDS WILL GRADUALLY VEER
THROUGH THE NIGHT. SOUTH WINDS WILL STRENGTHEN CONSIDERABLY LATE
IN THE TAF PERIOD WITH GUSTS OF 30 KT OR GREATER.
OUTLOOK...GUSTY SOUTHERLY WINDS WILL CONTINUE THROUGH LATE
THURSDAY AFTERNOON. A BRIEF PERIOD OF MVFR CEILINGS AND
VISIBILITIES ARE POSSIBLE AS SHOWERS AND THUNDERSTORMS MOVE
THROUGH LATE THURSDAY NIGHT AND EARLY FRIDAY MORNING. WEST WINDS
GUSTING TO 30 KT LIKELY FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...BINAU
NEAR TERM...BINAU
SHORT TERM...BINAU
LONG TERM...FRANKS
AVIATION...
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
341 PM EDT WED APR 17 2013
.SYNOPSIS...
LOW PRESSURE WILL TRACK NORTHEAST OUT OF THE PLAINS TONIGHT AND
LIFT A WARM FRONT NORTH ACROSS THE AREA. THIS SYSTEM WILL CONTINUE
TO TRACK NORTHEAST ACROSS THE GREAT LAKES REGION ON FRIDAY...PULLING
A STRONG COLD FRONT EAST ACROSS OHIO AND WESTERN PENNSYLVANIA.
HIGH PRESSURE WILL BUILD IN FOR SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
WARM FRONT/STATIONARY FRONT NEAR THE OHIO RIVER WITH LOW LEVEL ELY FLOW
ACROSS NRN OHIO. ELEVATED BAROCLINIC ZONE HOWEVER (925-850MB) IS
WELL NORTH OF THE SURFACE FRONT SHOWN BY THE RUC MODEL ACROSS NRN
INDIANA/SRN LWR MI. CAPES IN THE WARM SECTOR ARE 1-2000J/KG AND
WITH SLY FLOW OVERRUNNING THE BOUNDARY...CONVECTION IS OCCURRING
FROM NRN IL ACRS SRN LM INTO SRN LWR MI. STORM ALSO DEVELOPING IN
NRN INDIANA...MOVING INTO FAR NWRN OHIO. AS THE BAROCLINIC ZONE
LIFTS NORTH OVERNIGHT EXPECTING THE GENERATION ZONE FOR CONVECTION
TO ALSO LIFT. HOWEVER THROUGH THE EVENING CONCERNED WITH STORMS
GETTING INTO THE WESTERN/NWRN COUNTIES. WILL HAVE LIKELY POPS FAR
NORTHWEST WITH CHANCE ACROSS THE REMAINDER OF THE WESTERN COUNTIES.
EXPECTING FOCUS OF CONVECTION TO BE TO OUR NORTH AND WEST
OVERNIGHT BUT STILL KEPT CHANCE POPS FOR THE WEST HALF OF THE AREA
IN THE UNSTABLE AIR.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
AN ENERGETIC PATTERN FOR THE SHORT TERM WITH SEVERAL CONCERNS. FOR
THURSDAY...THE AREA WILL BE WELL INTO THE WARM SECTOR WITH HIGHS
FROM THE UPPER 70S TO AROUND 80. AS THE SYSTEM CONTINUES TO DEEPEN
TO OUR WEST SOUTHERLY FLOW WILL INCREASE THROUGH THE DAY. AM
CONCERNED ABOUT THE NEED FOR A WIND ADVISORY. WILL HAVE
STRONG/GUSTY WINDS IN THE FORECAST AND AN ADVISORY MAY BE NEEDED
ESPECIALLY FOR THE AFTERNOON/EVENING WITH DIURNAL HEATING AS THE
MOMENTUM MIXES DOWN. WINDS WILL REMAIN GUSTY THURSDAY NIGHT AHEAD
OF THE APPROACHING COLD FRONT HOWEVER BASED ON GUIDANCE...JUST
BELOW ADVISORY CRITERIA. STILL THE POTENTIAL FOR GUSTS COULD
REMAIN AS 850MB JET OF 70KTS WILL PASS ACROSS THE AREA. FRIDAY IN
COLD ADVECTION WINDS ARE AGAIN EXPECTED TO INCREASE BACK TO
ADVISORY LEVELS. BACK TO WEATHER...FOR THURSDAY WILL HAVE A LOW
CHANCE POP EVERYWHERE GUST GIVEN THE INSTABILITY WITH LIKELY POPS
IN THE AFTERNOON FAR NORTHWEST AS PREFRONTAL CONVECTION NEARS THE
AREA. THE STRONG COLD FRONT MOVES IN THURSDAY NIGHT FROM THE WEST
WITH BEST CHANCES AFTER MIDNIGHT. WILL HAVE CAT POPS SPREADING
EAST THROUGH THE NIGHT REACHING KCLE BY 12Z AND THEN CONTINUING
EAST AFTER 12Z WHILE THE WEST DRIES OUT IN STRONG SUBSIDENCE POST
FRONT. NOT CONVINCED PRECIP WILL BE OVER WEST AS WRAP AROUND
MOISTURE SPREADS BACK INTO THE AREA SO WILL MAINTAIN A CHANCE POP
FOR SHOWERS. SIGNIFICANT COOL DOWN POST FRONT WITH -11C AT 850MB OVER
THE LAKE SATURDAY MORNING. WILL LIKELY SEE LAKE EFFECT SNOW BUT AT
THIS TIME WILL NOT HAVE ACCUMS AS AIRMASS REALLY DRIES OUT AS
WELL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
FEW CHANGES IN THE EXTENDED FORECAST. MODELS CONTINUE TO MOVE HIGH
PRESSURE OFF THE NEW ENGLAND COAST ON SUNDAY ALLOWING SOUTHERLY FLOW
TO SET UP AND USHERING IN WARMER TEMPERATURES. HOWEVER WE WILL
STILL REMAIN BELOW NORMAL FOR TEMPS. GFS CONTINUES TO BE QUICKER
WITH THE NEXT SYSTEM THAN ECMWF...MOVING LOW INTO NW OHIO TUESDAY.
THE ECMWF ON THE OTHER HAND HOLDS OFF LOW UNTIL TUESDAY NIGHT. FOR
NOW WILL JUST KEEP CHANCE POPS GOING FOR NW OHIO ON TUESDAY. BEST
CHANCE FOR CONVECTION WILL BE TUESDAY NIGHT INTO WEDNESDAY.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
FRONT THAT MOVED ACROSS THE AREA MONDAY IS STALLED NEAR THE OHIO
RIVER. MODELS CONSISTENT MOVING THE FRONT NORTH AS A WARM FRONT
TONIGHT. AS THE FRONT LIFTS NORTH CIGS WILL GRADUALLY DROP TO IFR
FROM THE SOUTH OVERNIGHT. HOWEVER THINK IT WILL BE DIFFICULT FOR
IFR ALONG THE LAKESHORE WITH A SOUTHEAST FLOW SETTING UP OVERNIGHT.
BELIEVE THAT TREND IS RIGHT IN TAFS...BUT LOW CONFIDENCE ON THE
PRECISE TIMING OF THE FRONT.
CONDITIONS WILL IMPROVE TO VFR FROM THE SOUTH TOMORROW MORNING AS
THE FRONT LIFTS NORTH. HOWEVER...SOUTH-SOUTHWEST WINDS OF 20G30KT
WILL SET UP TOMORROW AFTERNOON AS LOW LEVEL JET SETS UP.
COULD SEE SOME SCATTERED SHOWERS/TSRA IN THE WEST TOMORROW
MORNING...AND ALMOST ANYWHERE TOMORROW AFTERNOON.
.OUTLOOK...NON VFR THURSDAY NIGHT AND FRIDAY IN TSRA/SHRA.
&&
.MARINE...
NORTHEAST FLOW ON THE LAKE THIS EVENING WILL SHIFT AROUND TO THE
SOUTHEAST BY MORNING AS A WARM FRONT PUSHES NORTH. A SMALL CRAFT
ADVISORY WILL BE NEEDED THURSDAY AS WINDS STEADILY INCREASE
THROUGHOUT THE DAY...HITTING/EXCEEDING THE 22 KNOT THRESHOLD.
THUNDERSTORMS WILL BE POSSIBLE JUST ABOUT ANYTIME BETWEEN NOW
THROUGH FRIDAY...BUT THE STRONG COLD FRONT WITH THIS SYSTEM WILL BE
CROSSING THE FRIDAY. THERE WILL BE SIGNIFICANT GUSTS WITH ANY
CONVECTION THURSDAY NIGHT/FRIDAY AND THEN SUSTAINED WINDS WILL
INCREASE WITH THE COLD AIR ADVECTION FROM THE WEST-SOUTHWEST FRIDAY
AFTERNOON. WINDS STILL MAY BE APPROACHING GALE FORCE FRIDAY
AFTERNOON/EVENING. CONDITIONS ON THE LAKE IMPROVE SATURDAY AS HIGH
PRESSURE MOVES OVERHEAD. SUNDAY WILL BE QUIET. THE HIGH WILL HAVE
SHIFTED EAST MONDAY...ALLOWING FOR SOUTHERLY FLOW AGAIN ON THE LAKE.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK
SHORT TERM...TK
LONG TERM...DJB
AVIATION...DJB
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
638 AM EDT WED APR 17 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN STALLED ACROSS THE REGION
TODAY...LIFTING NORTH OF THE REGION AS A WARM FRONT BY TONIGHT.
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE. WARM SOUTHERLY FLOW WILL
EXIST OVER THE REGION ON THURSDAY...BEFORE A STRONG COLD FRONT
BRINGS SHOWERS AND STORMS (AND MUCH COLDER TEMPERATURES) EARLY
FRIDAY MORNING. COOLER CONDITIONS ARE EXPECTED FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THUNDER CONTINUES TO RUMBLE ACROSS THE REGION EARLY THIS
MORNING...PARTICULARLY ACROSS THE IND AND ILN FORECAST AREAS.
CONVECTION IS REPEATEDLY DEVELOPING ON THE COOL SIDE OF THE
SURFACE BOUNDARY...AIDED BY QUITE A BIT OF CONVERGENCE AND
MOISTURE TRANSPORT JUST OFF THE SURFACE. THIS FORCING WAS TOUGH TO
PICK OUT...AS IT APPEARS TO BE WITHIN A LAYER OF SOUTHWESTERLY
FLOW FROM JUST OFF THE SURFACE TO AROUND 875MB. WINDS AT 850MB
AND ABOVE ARE MORE WESTERLY THAN SOUTHWESTERLY.
ALL SIGNS (QPF OUTPUT...HIGH-RES SIMULATED REFLECTIVITY...AND A
WEAKENING TO THE SOUTHWESTERLY FLOW) POINT TOWARD A GRADUAL
WEAKENING TREND LATER IN MORNING HOURS. HOWEVER...THE ACTIVITY IS
EXPECTED TO PERSIST FOR THE NEXT SEVERAL HOURS AT LEAST...AND THE
RECENT HRRR RUNS ARE FINALLY PICKING UP ON THIS A BIT (THOUGH THEY
SEEM TO MOVE THE CONVECTION ON TOO SOUTHERLY A TRAJECTORY). POPS
ARE VERY HIGH (AS HIGH AS 100 PERCENT) DURING THE EARLY
MORNING...BEFORE DIMINISHING SIGNIFICANTLY BY LATE MORNING AND
AFTERNOON.
THE FRONTAL BOUNDARY WILL BEGIN TO LIFT NORTH LATER TODAY...BUT IT
IS NOT AS WELL DEFINED AS IT WAS YESTERDAY. SUPPORT FOR FORCING IS
ALSO NOT ESPECIALLY STRONG...AS 500MB HEIGHTS RISE.
THEREFORE...CONVECTION IS NOT EXPECTED TO BE AS WIDESPREAD AS IT
WAS ON TUESDAY...NOR WILL IT BE LIKELY TO BE AS STRONG. THERE
SHOULD BE ENOUGH INSTABILITY ALONG AND SOUTH OF THE BOUNDARY TO
SUPPORT A LOW-END SEVERE THREAT...BUT SHEAR IS NOT IMPRESSIVE
(20-30 KNOTS 0-6KM...PERHAPS EVEN LESS IN THE FAR SOUTH).
TEMPERATURE LEVELS WILL ALSO BE RISING A BIT FROM WHERE THEY ARE
AT NOW (AND WHERE THEY WERE LAST EVENING). SO...THE HWO WILL
INCLUDE A HEDGED MENTION...AS SEVERE WEATHER LOOKS UNLIKELY BUT
NOT TOTALLY IMPOSSIBLE.
TEMPS WERE NOT EASY TODAY...GIVEN THE ABUNDANCE OF CLOUDS AND THE
TOUGH FORECAST FOR THE LOCATION OF THE BOUNDARY. TEMPS WERE KEPT
CLOSE TO GUIDANCE...THOUGH COOLER THAN THE RAW NAM12. THE GRADIENT
ACROSS THE CWA IS TIGHT...WITH UPPER 70S IN THE FAR SOUTH AND MID
60S IN THE FAR NORTH. DEPENDING ON HOW SLOW THE MORNING CONVECTION
DISSIPATES...THERE COULD BE BUST POTENTIAL WITH THESE NUMBERS
BEING TOO HIGH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE FRONTAL BOUNDARY WILL BE NORTH OF THE REGION BY WEDNESDAY
NIGHT...WITH THE CWA UNDER A MID-LEVEL RIDGE AND ENTERING A REGIME
OF SOUTHERLY FLOW. THIS SHOULD LOCK MOST OF THE CWA (ALL BUT THE
NORTHWEST CORNER) IN THE WARM SECTOR...HELPING TO SIGNIFICANTLY
DIMINISH CHANCES OF PRECIPITATION THROUGH THE DAY ON THURSDAY.
WHILE SOME DIURNAL CONVECTION MAY BE POSSIBLE AT THE NORTH AND
WEST FRINGES OF THE CWA ON THURSDAY AFTERNOON...A LACK OF FORCING
AND PERHAPS SOME CAPPING WILL LIMIT THIS POTENTIAL. THE
SOUTHEASTERN HALF OF THE CWA SHOULD ALMOST CERTAINLY REMAIN DRY.
AS THE SOUTHWESTERLY FLOW INCREASES...AND CONDITIONS MIX RATHER
WELL ON THURSDAY...WIND GUSTS INTO THE 30-40 MPH RANGE APPEAR
POSSIBLE. IN FACT...BOTH THE GFS/NAM ARE SHOWING GUSTS AS HIGH AS
45 MPH ON BUFKIT IN THE FAR NORTH (NEAR LIMA OH). WITH THE STRONG
WARM ADVECTION...THE MAX TEMP FORECAST FOR THURSDAY REMAINS WELL
ABOVE NORMAL...WITH MID 80S IN THE SOUTHEAST PART OF THE CWA.
MODELS APPEAR TO BE IN VERY GOOD AGREEMENT ON THE BIG CONCLUSION
TO THE UNSETTLED WEATHER THIS WEEK. LOW PRESSURE IS FORECAST TO
MOVE NORTHEAST TOWARD CHICAGO BY THURSDAY NIGHT...AND THEN ONWARD
TO THE STRAITS OF MACKINAC BY FRIDAY MORNING. A STRONG COLD FRONT
WILL MOVE EASTWARD THROUGH THE MISSISSIPPI VALLEY THURSDAY
EVENING...AND THEN THROUGH THE OHIO VALLEY INTO THE ILN CWA BY
EARLY FRIDAY MORNING.
SPC HAS PLACED A LARGE AREA INTO A HIGH-END SLIGHT
RISK ON DAY2. THIS RISK AREA IS GENERALLY ALONG AND AHEAD OF THE
EXPECTED POSITION OF THE COLD FRONT...AS IT PROGRESSES FROM THE
AFTERNOON INTO THE EARLY OVERNIGHT HOURS ON THURSDAY. THERE IS NO
QUESTION THAT THE BEST SEVERE POTENTIAL IS WEST OF THE ILN
CWA...WHERE DIURNAL INSTABILITY WILL BE GREATEST. HOWEVER...SHEAR
WILL CONTINUE TO BE VERY STRONG EVEN THROUGH THE OVERNIGHT HOURS
AND INTO FRIDAY MORNING. FLOW AT ALL LEVELS WILL INCREASE AHEAD OF
THE FRONT...WITH A LOW-LEVEL JET OF 60-70 KNOTS AT 850MB NEAR 06Z.
INSTABILITY WILL BE THE POTENTIAL LIMITING FACTOR FOR SEVERE
WEATHER...GIVEN UNFAVORABLE NEAR-SURFACE THERMODYNAMIC PROFILES AT
THE TIME THE WEAKENING FRONTAL CONVECTION IS MOVING INTO THE CWA.
AT THEIR MOST FAVORABLE...SOME OF THE MODEL SOUNDINGS ARE ROUGHLY
MOIST-ADIABATIC...WHILE OTHERS DISPLAY MORE OF A SLIGHTLY-INVERTED
PROFILE.
THIS SCENARIO WILL BE CLOSELY MONITORED OVER THE NEXT FEW
DAYS...AS THE STRONG WIND FIELDS MEAN THAT SEVERE WEATHER COULD BE
POSSIBLE EVEN WITH THE UNFAVORABLE TIMING. EVEN ASIDE FROM THE
CONVECTIVE POTENTIAL...BUFKIT SOUNDINGS ARE INDICATING WIND GUSTS
OF 25-30 KNOTS BEHIND THE FRONT. THE PROGRESSIVE NATURE OF THE
FRONT WILL LIKELY LIMIT ANY POTENTIAL FLOODING ISSUES...BUT THE
MOISTURE TRANSPORT APPEARS TO BE VERY STRONG...AND RAINFALL
AMOUNTS OF OVER AN INCH WILL BE POSSIBLE (ESPECIALLY IN THE
WESTERN HALF OF THE CWA).
NON-DIURNAL TEMPS WERE DRAWN IN FOR FRIDAY...WITH MAX TEMPS
EXPECTED IN THE MORNING...AND A SIGNIFICANT DECREASE BEHIND THE
FRONT. AS AN EXAMPLE OF THE EXPECTED CHANGE IN AIR MASS...NAM12
850MB TEMPS AT KILN ARE FORECAST TO GO FROM +14C AT 06Z FRIDAY
MORNING TO -5C JUST 24 HOURS LATER.
BEHIND THE FRONT...LOW LEVEL MOISTURE IS EXPECTED TO BE VERY SLOW
TO SCOUR OUT. SOME TROUGHING ALOFT WILL BRING A SLIGHT CHANCE OF
SHOWERS TO THE NORTHERN CWA ON FRIDAY AFTERNOON...BUT A LACK OF
DEEPER MOISTURE IS LIMITING QPF AMOUNTS TO JUST A FEW HUNDREDTHS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
HIGH PRESSURE AND DRY AIR WILL BUILD IN FOR SATURDAY THROUGH MONDAY.
ANOTHER STRONG COLD FRONT WILL APPROACH FROM THE WEST ON TUESDAY
BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AFTERNOON.
AFTER A MORNING HIGH NEAR 60 ON FRIDAY...HIGHS WILL BE MAINLY IN THE
50S SATURDAY AND SUNDAY. A REBOUND BACK INTO THE 60S IS INDICATED
FOR MONDAY AND TUESDAY AS WARM ADVECTION OCCURS IN THE RETURN FLOW
OF HIGH PRESSURE. TO COINCIDE WITH THE START OF OUR FROST/FREEZE
PROGRAM FOR THE ENTIRE ILN AREA...FROST WILL BE POSSIBLE SUNDAY
MORNING WHEN TEMPERATURES ARE FORECAST TO FALL TO THE LOWER TO
MIDDLE 30S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
A NEARLY STATIONARY FRONT NEAR THE OHIO RIVER THIS MORNING WILL
MOVE SLOWLY BACK NORTH AS A WARM FRONT TODAY...AND WILL LIFT INTO
THE SOUTHERN GREAT LAKES TONIGHT.
SCATTERED SHOWERS AND A FEW RUMBLES OF THUNDER THIS MORNING SHOULD
DWINDLE IN COVERAGE AS A WEAK LOW LEVEL JET/CONVERGENCE AXIS
NORTH OF THE STATIONARY BOUNDARY EVENTUALLY WEAKEN BY MID DAY.
THEREAFTER...PROSPECTS OF CONTINUE CONVECTION APPEAR LOW AT THIS
TIME AND WILL DEPEND ON HOW MUCH SURFACE BASED INSTABILITY CAN BE
REALIZED NEAR THE FRONT. DO NOT HAVE CONFIDENCE TO PLACE IN THE
TAFS AT THIS TIME SO HAVE LEFT OUT.
THE OTHER CONCERN THIS MORNING INTO THE EARLY AFTERNOON HOURS WILL
BE THE AMPLE LOW LEVEL MOISTURE THAT IS IN PLACE FROM THE RECENT
RAINS. THIS WILL LIKELY YIELD IFR CIGS AND MVFR VSBYS EARLY ON.
DAYTIME HEATING SHOULD ALLOW BOTH TO IMPROVE TO VFR DURING THE
AFTERNOON HOURS.
FOR TONIGHT...LARGE SCALE MID LVL TROUGH WILL PUSH EAST INTO THE
PLAINS. THIS WILL ALLOW THE MID LVL FLOW TO BUCKLE AS WARM FRONT
ADVANCES NORTH INTO THE SOUTHERN GREAT LAKES. SOME MODELS SUGGEST
THAT SOME CONVECTION COULD GRAZE OUR WESTERN FORECAST AREA EARLY
ON..BUT CONFIDENCE IN THIS IS LOW ATTM SO HAVE MAINTAINED A DRY
FORECAST. OTHERWISE...VFR CONDITIONS ARE EXPECTED OVERNIGHT.
OUTLOOK...GUSTY SOUTH/SOUTHWEST WINDS OF 30 TO 35 KNOTS LIKELY ON
THURSDAY. SHOWERS AND THUNDERSTORMS THURSDAY NIGHT INTO FRIDAY.
GUSTY WEST WINDS TO 30 KNOTS LIKELY BEHIND FRONTAL PASSAGE ON
FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...CONIGLIO
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
432 AM EDT WED APR 17 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN STALLED ACROSS THE REGION
TODAY...LIFTING NORTH OF THE REGION AS A WARM FRONT BY TONIGHT.
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE. WARM SOUTHERLY FLOW WILL
EXIST OVER THE REGION ON THURSDAY...BEFORE A STRONG COLD FRONT
BRINGS SHOWERS AND STORMS (AND MUCH COLDER TEMPERATURES) EARLY
FRIDAY MORNING. COOLER CONDITIONS ARE EXPECTED FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THUNDER CONTINUES TO RUMBLE ACROSS THE REGION EARLY THIS
MORNING...PARTICULARLY ACROSS THE IND AND ILN FORECAST AREAS.
CONVECTION IS REPEATEDLY DEVELOPING ON THE COOL SIDE OF THE
SURFACE BOUNDARY...AIDED BY QUITE A BIT OF CONVERGENCE AND
MOISTURE TRANSPORT JUST OFF THE SURFACE. THIS FORCING WAS TOUGH TO
PICK OUT...AS IT APPEARS TO BE WITHIN A LAYER OF SOUTHWESTERLY
FLOW FROM JUST OFF THE SURFACE TO AROUND 875MB. WINDS AT 850MB
AND ABOVE ARE MORE WESTERLY THAN SOUTHWESTERLY.
ALL SIGNS (QPF OUTPUT...HIGH-RES SIMULATED REFLECTIVITY...AND A
WEAKENING TO THE SOUTHWESTERLY FLOW) POINT TOWARD A GRADUAL
WEAKENING TREND LATER IN MORNING HOURS. HOWEVER...THE ACTIVITY IS
EXPECTED TO PERSIST FOR THE NEXT SEVERAL HOURS AT LEAST...AND THE
RECENT HRRR RUNS ARE FINALLY PICKING UP ON THIS A BIT (THOUGH THEY
SEEM TO MOVE THE CONVECTION ON TOO SOUTHERLY A TRAJECTORY). POPS
ARE VERY HIGH (AS HIGH AS 100 PERCENT) DURING THE EARLY
MORNING...BEFORE DIMINISHING SIGNIFICANTLY BY LATE MORNING AND
AFTERNOON.
THE FRONTAL BOUNDARY WILL BEGIN TO LIFT NORTH LATER TODAY...BUT IT
IS NOT AS WELL DEFINED AS IT WAS YESTERDAY. SUPPORT FOR FORCING IS
ALSO NOT ESPECIALLY STRONG...AS 500MB HEIGHTS RISE.
THEREFORE...CONVECTION IS NOT EXPECTED TO BE AS WIDESPREAD AS IT
WAS ON TUESDAY...NOR WILL IT BE LIKELY TO BE AS STRONG. THERE
SHOULD BE ENOUGH INSTABILITY ALONG AND SOUTH OF THE BOUNDARY TO
SUPPORT A LOW-END SEVERE THREAT...BUT SHEAR IS NOT IMPRESSIVE
(20-30 KNOTS 0-6KM...PERHAPS EVEN LESS IN THE FAR SOUTH).
TEMPERATURE LEVELS WILL ALSO BE RISING A BIT FROM WHERE THEY ARE
AT NOW (AND WHERE THEY WERE LAST EVENING). SO...THE HWO WILL
INCLUDE A HEDGED MENTION...AS SEVERE WEATHER LOOKS UNLIKELY BUT
NOT TOTALLY IMPOSSIBLE.
TEMPS WERE NOT EASY TODAY...GIVEN THE ABUNDANCE OF CLOUDS AND THE
TOUGH FORECAST FOR THE LOCATION OF THE BOUNDARY. TEMPS WERE KEPT
CLOSE TO GUIDANCE...THOUGH COOLER THAN THE RAW NAM12. THE GRADIENT
ACROSS THE CWA IS TIGHT...WITH UPPER 70S IN THE FAR SOUTH AND MID
60S IN THE FAR NORTH. DEPENDING ON HOW SLOW THE MORNING CONVECTION
DISSIPATES...THERE COULD BE BUST POTENTIAL WITH THESE NUMBERS
BEING TOO HIGH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE FRONTAL BOUNDARY WILL BE NORTH OF THE REGION BY WEDNESDAY
NIGHT...WITH THE CWA UNDER A MID-LEVEL RIDGE AND ENTERING A REGIME
OF SOUTHERLY FLOW. THIS SHOULD LOCK MOST OF THE CWA (ALL BUT THE
NORTHWEST CORNER) IN THE WARM SECTOR...HELPING TO SIGNIFICANTLY
DIMINISH CHANCES OF PRECIPITATION THROUGH THE DAY ON THURSDAY.
WHILE SOME DIURNAL CONVECTION MAY BE POSSIBLE AT THE NORTH AND
WEST FRINGES OF THE CWA ON THURSDAY AFTERNOON...A LACK OF FORCING
AND PERHAPS SOME CAPPING WILL LIMIT THIS POTENTIAL. THE
SOUTHEASTERN HALF OF THE CWA SHOULD ALMOST CERTAINLY REMAIN DRY.
AS THE SOUTHWESTERLY FLOW INCREASES...AND CONDITIONS MIX RATHER
WELL ON THURSDAY...WIND GUSTS INTO THE 30-40 MPH RANGE APPEAR
POSSIBLE. IN FACT...BOTH THE GFS/NAM ARE SHOWING GUSTS AS HIGH AS
45 MPH ON BUFKIT IN THE FAR NORTH (NEAR LIMA OH). WITH THE STRONG
WARM ADVECTION...THE MAX TEMP FORECAST FOR THURSDAY REMAINS WELL
ABOVE NORMAL...WITH MID 80S IN THE SOUTHEAST PART OF THE CWA.
MODELS APPEAR TO BE IN VERY GOOD AGREEMENT ON THE BIG CONCLUSION
TO THE UNSETTLED WEATHER THIS WEEK. LOW PRESSURE IS FORECAST TO
MOVE NORTHEAST TOWARD CHICAGO BY THURSDAY NIGHT...AND THEN ONWARD
TO THE STRAITS OF MACKINAC BY FRIDAY MORNING. A STRONG COLD FRONT
WILL MOVE EASTWARD THROUGH THE MISSISSIPPI VALLEY THURSDAY
EVENING...AND THEN THROUGH THE OHIO VALLEY INTO THE ILN CWA BY
EARLY FRIDAY MORNING.
SPC HAS PLACED A LARGE AREA INTO A HIGH-END SLIGHT
RISK ON DAY2. THIS RISK AREA IS GENERALLY ALONG AND AHEAD OF THE
EXPECTED POSITION OF THE COLD FRONT...AS IT PROGRESSES FROM THE
AFTERNOON INTO THE EARLY OVERNIGHT HOURS ON THURSDAY. THERE IS NO
QUESTION THAT THE BEST SEVERE POTENTIAL IS WEST OF THE ILN
CWA...WHERE DIURNAL INSTABILITY WILL BE GREATEST. HOWEVER...SHEAR
WILL CONTINUE TO BE VERY STRONG EVEN THROUGH THE OVERNIGHT HOURS
AND INTO FRIDAY MORNING. FLOW AT ALL LEVELS WILL INCREASE AHEAD OF
THE FRONT...WITH A LOW-LEVEL JET OF 60-70 KNOTS AT 850MB NEAR 06Z.
INSTABILITY WILL BE THE POTENTIAL LIMITING FACTOR FOR SEVERE
WEATHER...GIVEN UNFAVORABLE NEAR-SURFACE THERMODYNAMIC PROFILES AT
THE TIME THE WEAKENING FRONTAL CONVECTION IS MOVING INTO THE CWA.
AT THEIR MOST FAVORABLE...SOME OF THE MODEL SOUNDINGS ARE ROUGHLY
MOIST-ADIABATIC...WHILE OTHERS DISPLAY MORE OF A SLIGHTLY-INVERTED
PROFILE.
THIS SCENARIO WILL BE CLOSELY MONITORED OVER THE NEXT FEW
DAYS...AS THE STRONG WIND FIELDS MEAN THAT SEVERE WEATHER COULD BE
POSSIBLE EVEN WITH THE UNFAVORABLE TIMING. EVEN ASIDE FROM THE
CONVECTIVE POTENTIAL...BUFKIT SOUNDINGS ARE INDICATING WIND GUSTS
OF 25-30 KNOTS BEHIND THE FRONT. THE PROGRESSIVE NATURE OF THE
FRONT WILL LIKELY LIMIT ANY POTENTIAL FLOODING ISSUES...BUT THE
MOISTURE TRANSPORT APPEARS TO BE VERY STRONG...AND RAINFALL
AMOUNTS OF OVER AN INCH WILL BE POSSIBLE (ESPECIALLY IN THE
WESTERN HALF OF THE CWA).
NON-DIURNAL TEMPS WERE DRAWN IN FOR FRIDAY...WITH MAX TEMPS
EXPECTED IN THE MORNING...AND A SIGNIFICANT DECREASE BEHIND THE
FRONT. AS AN EXAMPLE OF THE EXPECTED CHANGE IN AIR MASS...NAM12
850MB TEMPS AT KILN ARE FORECAST TO GO FROM +14C AT 06Z FRIDAY
MORNING TO -5C JUST 24 HOURS LATER.
BEHIND THE FRONT...LOW LEVEL MOISTURE IS EXPECTED TO BE VERY SLOW
TO SCOUR OUT. SOME TROUGHING ALOFT WILL BRING A SLIGHT CHANCE OF
SHOWERS TO THE NORTHERN CWA ON FRIDAY AFTERNOON...BUT A LACK OF
DEEPER MOISTURE IS LIMITING QPF AMOUNTS TO JUST A FEW HUNDREDTHS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
HIGH PRESSURE AND DRY AIR WILL BUILD IN FOR SATURDAY THROUGH MONDAY.
ANOTHER STRONG COLD FRONT WILL APPROACH FROM THE WEST ON TUESDAY
BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AFTERNOON.
AFTER A MORNING HIGH NEAR 60 ON FRIDAY...HIGHS WILL BE MAINLY IN THE
50S SATURDAY AND SUNDAY. A REBOUND BACK INTO THE 60S IS INDICATED
FOR MONDAY AND TUESDAY AS WARM ADVECTION OCCURS IN THE RETURN FLOW
OF HIGH PRESSURE. TO COINCIDE WITH THE START OF OUR FROST/FREEZE
PROGRAM FOR THE ENTIRE ILN AREA...FROST WILL BE POSSIBLE SUNDAY
MORNING WHEN TEMPERATURES ARE FORECAST TO FALL TO THE LOWER TO
MIDDLE 30S.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
A NEARLY STATIONARY FRONT NEAR THE OHIO RIVER THIS MORNING WILL
MOVE SLOWLY BACK NORTH AS A WARM FRONT TODAY...AND WILL LIFT INTO
THE SOUTHERN GREAT LAKES TONIGHT.
COMPLEX TAF PROBLEM THIS MORNING GIVEN AMPLE LOW LEVEL MOISTURE
AND ONGOING ELEVATED CONVECTION. AN EMBEDDED WEATHER DISTURBANCE
WILL RIDE WEST TO EAST ALONG AFOREMENTIONED STATIONARY FRONT THIS
MORNING. THIS WILL KEEP THE THREAT FOR SHOWERS AND THUNDERSTORMS
GOING THROUGH DAYBREAK...BUT WITH ACTIVITY AND COVERAGE DECREASING
BY THEN AS WELL. PREVIOUS CONVECTION FROM THE AFTERNOON AND
EVENING ON TUESDAY HAS PROVIDED AMPLE LOW LEVEL MOISTURE...AND ON
THE COOL SIDE OF THE BOUNDARY...LOW STRATUS HAS FORMED. THUS...AM
EXPECTING CIGS TO BE NEAR OR BELOW ALTERNATE MINS AT THE TAF SITES
OUTSIDE OF CONVECTION...WHICH IN THE CONVECTION ITSELF...CIGS MAY
ACTUALLY TEMPORARILY LIFT TO MVFR DUE TO MIXING. VSBYS WILL BE
MVFR WITH IFR VSBYS POSSIBLE IN HEAVIER PCPN.
FOR LATER THIS MORNING AND THIS AFTN...FRONTAL BOUNDARY WILL BE
SLOW TO MOVE NORTH AND AS SUCH IT WILL TAKE SOME TIME FOR LOW
LEVEL MOISTURE TO MIX INTO A LOW VFR CUMULUS DECK. AM HAVING A
HARD TIME FINDING ANY SUPPLEMENTAL TRIGGERING MECHANISMS FOR
SHOWERS AND STORMS OTHER THAN THE FRONTAL BOUNDARY ITSELF THIS
AFTERNOON SO HAVE KEPT A MENTION OF VCTS/CB AT THE SRN/WRN TAF
SITES WHERE THREAT IS THE HIGHEST.
FOR TONIGHT...LARGE SCALE MID LVL TROUGH WILL PUSH EAST INTO THE
PLAINS. THIS WILL ALLOW THE MID LVL FLOW TO BUCKLE AS WARM FRONT
ADVANCES NORTH INTO THE SOUTHERN GREAT LAKES. SOME MODELS SUGGEST
THAT SOME CONVECTION COULD GRAZE OUR WESTERN FORECAST AREA EARLY
ON..BUT CONFIDENCE IN THIS IS LOW ATTM SO HAVE MAINTAINED A DRY
FORECAST. OTHERWISE...VFR CONDITIONS ARE EXPECTED OVERNIGHT.
OUTLOOK...GUSTY SOUTH/SOUTHWEST WINDS TO 30 KNOTS ON THURSDAY.
SHOWERS AND THUNDERSTORMS THURSDAY NIGHT INTO FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...CONIGLIO
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
409 AM EDT WED APR 17 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN STALLED ACROSS THE REGION
TODAY...LIFTING NORTH OF THE REGION AS A WARM FRONT BY TONIGHT.
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE. WARM SOUTHERLY FLOW WILL
EXIST OVER THE REGION ON THURSDAY...BEFORE A STRONG COLD FRONT
BRINGS SHOWERS AND STORMS (AND MUCH COLDER TEMPERATURES) EARLY
FRIDAY MORNING. COOLER CONDITIONS ARE EXPECTED FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THUNDER CONTINUES TO RUMBLE ACROSS THE REGION EARLY THIS
MORNING...PARTICULARLY ACROSS THE IND AND ILN FORECAST AREAS.
CONVECTION IS REPEATEDLY DEVELOPING ON THE COOL SIDE OF THE
SURFACE BOUNDARY...AIDED BY QUITE A BIT OF CONVERGENCE AND
MOISTURE TRANSPORT JUST OFF THE SURFACE. THIS FORCING WAS TOUGH TO
PICK OUT...AS IT APPEARS TO BE WITHIN A LAYER OF SOUTHWESTERLY
FLOW FROM JUST OFF THE SURFACE TO AROUND 875MB. WINDS AT 850MB
AND ABOVE AE MORE WESTERLY THAN SOUTHWESTERLY.
ALL SIGNS (QPF OUTPUT...HIGH-RES SIMULATED REFLECTIVITY...AND A
WEAKENING TO THE SOUTHWESTERLY FLOW) POINT TOWARD A GRADUAL
WEAKENING TREND LATER IN MORNING HOURS. HOWEVER...THE ACTIVITY IS
EXPECTED TO PERSIST FOR THE NEXT SEVERAL HOURS AT LEAST...AND THE
RECENT HRRR RUNS ARE FINALLY PICKING UP ON THIS A BIT (THOUGH THEY
SEEM TO MOVE THE CONVECTION ON TOO SOUTHERLY A TRAJECTORY). POPS
ARE VERY HIGH (AS HIGH AS 100 PERCENT) DURING THE EARLY
MORNING...BEFORE DIMINISHING SIGNIFICANTLY BY LATE MORNING AND
AFTERNOON.
THE FRONTAL BOUNDARY WILL BEGIN TO LIFT NORTH LATER TODAY...BUT IT
IS NOT AS WELL DEFINED AS IT WAS YESTERDAY. SUPPORT FOR FORCING IS
ALSO NOT ESPECIALLY STRONG...AS 500MB HEIGHTS RISE.
THEREFORE...CONVECTION IS NOT EXPECTED TO BE AS WIDESPREAD AS IT
WAS ON TUESDAY...NOR WILL IT BE LIKELY TO BE AS STRONG. THERE
SHOULD BE ENOUGH INSTABILITY ALONG AND SOUTH OF THE BOUNDARY TO
SUPPORT A LOW-END SEVERE THREAT...BUT SHEAR IS NOT IMPRESSIVE
(20-30 KNOTS 0-6KM...PERHAPS EVEN LESS IN THE FAR SOUTH).
TEMPERATURE LEVELS WILL ALSO BE RISING A BIT FROM WHERE THEY ARE
AT NOW (AND WHERE THEY WERE LAST EVENING). SO...THE HWO WILL
INCLUDE A HEDGED MENTION...AS SEVERE WEATHER LOOKS UNLIKELY BUT
NOT TOTALLY IMPOSSIBLE.
TEMPS WERE NOT EASY TODAY...GIVEN THE ABUNDANCE OF CLOUDS AND THE
TOUGH FORECAST FOR THE LOCATION OF THE BOUNDARY. TEMPS WERE KEPT
CLOSE TO GUIDANCE...THOUGH COOLER THAN THE RAW NAM12. THE GRADIENT
ACROSS THE CWA IS TIGHT...WITH UPPER 70S IN THE FAR SOUTH AND MID
60S IN THE FAR NORTH. DEPENDING ON HOW SLOW THE MORNING CONVECTION
DISSIPATES...THERE COULD BE BUST POTENTIAL WITH THESE NUMBERS
BEING TOO HIGH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
(UPDATED SHORT TERM DISCUSSION COMING SOON)
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
STRONG COLD FRONT WILL BE EXITING TO THE EAST ON FRIDAY. SHOWERS
AND THUNDERSTORMS WILL BE ENDING FROM EAST TO WEST. HIGH
TEMPERATURES WILL PROBABLY OCCUR IN THE MORNING WITH COLDER AIR
RUSHING IN ON A BRISK WESTERLY FLOW BEHIND THE FRONT.
HIGH PRESSURE AND DRY AIR WILL BUILD IN FOR SATURDAY THROUGH MONDAY.
ANOTHER STRONG COLD FRONT WILL APPROACH FROM THE WEST ON TUESDAY
BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AFTERNOON.
AFTER A MORNING HIGH NEAR 60 ON FRIDAY...HIGHS WILL BE MAINLY IN THE
50S SATURDAY AND SUNDAY. A REBOUND BACK INTO THE 60S IS INDICATED
FOR MONDAY AND TUESDAY AS WARM ADVECTION OCCURS IN THE RETURN FLOW
OF HIGH PRESSURE. TO COINCIDE WITH THE START OF OUR FROST/FREEZE
PROGRAM FOR THE ENTIRE ILN AREA...FROST WILL BE POSSIBLE SUNDAY
MORNING WHEN TEMPERATURES ARE FORECAST TO FALL TO THE LOWER TO
MIDDLE 30S.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
A NEARLY STATIONARY FRONT NEAR THE OHIO RIVER THIS MORNING WILL
MOVE SLOWLY BACK NORTH AS A WARM FRONT TODAY...AND WILL LIFT INTO
THE SOUTHERN GREAT LAKES TONIGHT.
COMPLEX TAF PROBLEM THIS MORNING GIVEN AMPLE LOW LEVEL MOISTURE
AND ONGOING ELEVATED CONVECTION. AN EMBEDDED WEATHER DISTURBANCE
WILL RIDE WEST TO EAST ALONG AFOREMENTIONED STATIONARY FRONT THIS
MORNING. THIS WILL KEEP THE THREAT FOR SHOWERS AND THUNDERSTORMS
GOING THROUGH DAYBREAK...BUT WITH ACTIVITY AND COVERAGE DECREASING
BY THEN AS WELL. PREVIOUS CONVECTION FROM THE AFTERNOON AND
EVENING ON TUESDAY HAS PROVIDED AMPLE LOW LEVEL MOISTURE...AND ON
THE COOL SIDE OF THE BOUNDARY...LOW STRATUS HAS FORMED. THUS...AM
EXPECTING CIGS TO BE NEAR OR BELOW ALTERNATE MINS AT THE TAF SITES
OUTSIDE OF CONVECTION...WHICH IN THE CONVECTION ITSELF...CIGS MAY
ACTUALLY TEMPORARILY LIFT TO MVFR DUE TO MIXING. VSBYS WILL BE
MVFR WITH IFR VSBYS POSSIBLE IN HEAVIER PCPN.
FOR LATER THIS MORNING AND THIS AFTN...FRONTAL BOUNDARY WILL BE
SLOW TO MOVE NORTH AND AS SUCH IT WILL TAKE SOME TIME FOR LOW
LEVEL MOISTURE TO MIX INTO A LOW VFR CUMULUS DECK. AM HAVING A
HARD TIME FINDING ANY SUPPLEMENTAL TRIGGERING MECHANISMS FOR
SHOWERS AND STORMS OTHER THAN THE FRONTAL BOUNDARY ITSELF THIS
AFTERNOON SO HAVE KEPT A MENTION OF VCTS/CB AT THE SRN/WRN TAF
SITES WHERE THREAT IS THE HIGHEST.
FOR TONIGHT...LARGE SCALE MID LVL TROUGH WILL PUSH EAST INTO THE
PLAINS. THIS WILL ALLOW THE MID LVL FLOW TO BUCKLE AS WARM FRONT
ADVANCES NORTH INTO THE SOUTHERN GREAT LAKES. SOME MODELS SUGGEST
THAT SOME CONVECTION COULD GRAZE OUR WESTERN FORECAST AREA EARLY
ON..BUT CONFIDENCE IN THIS IS LOW ATTM SO HAVE MAINTAINED A DRY
FORECAST. OTHERWISE...VFR CONDITIONS ARE EXPECTED OVERNIGHT.
OUTLOOK...GUSTY SOUTH/SOUTHWEST WINDS TO 30 KNOTS ON THURSDAY.
SHOWERS AND THUNDERSTORMS THURSDAY NIGHT INTO FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...CONIGLIO
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS TULSA OK
632 AM CDT WED APR 17 2013
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
ACTIVE TAF PERIOD WITH TSRA CHANCES INCREASING AT ALL TAF SITES...
ESPECIALLY AFTER 00Z. MVFR CIGS EXPECTED THROUGH 16-18Z...WITH
A BRIEF WINDOW FOR VFR CONDITIONS THROUGH LATE AFTERNOON. CIGS TO
LOWER TO MVFR CATEGORIES FROM LATE AFTERNOON THROUGH THE REST OF
THE TAF PERIOD. TSRA WILL START TO BECOMING MORE WIDESPREAD...AND
AFFECTING THE OK TAF SITES AFTER SUNSET. WINDS WILL SHIFT TO THE
NORTHWEST WITH FROPA AROUND 09Z. MVFR CIGS AND RAIN TO CONTINUE
BEHIND THE FRONT.
&&
.PREV DISCUSSION... /ISSUED 422 AM CDT WED APR 17 2013/
DISCUSSION...
FRONTAL BOUNDARY HAS BEGUN TO SLOWLY LIFT NORTH AS A WARM FRONT
AND THE NORTHWARD PROGRESS OF THIS FRONT SHOULD ACCELERATE OVER
THE NEXT FEW HOURS WITH THE ENTIRE FORECAST AREA IN THE WARM
SECTOR BY LATER THIS MORNING. CONVECTIVE EVOLUTION TODAY IS
UNCLEAR WITH A MYRIAD OF SOLUTIONS DEPICTED BY THE VARIOUS MODELS.
LARGE SCALE HEIGHT FALLS WILL BEGIN THIS MORNING AHEAD OF THE
UPPER SYSTEM CURRENTLY IN UTAH AND THIS SHOULD RESULT IN A
WEAKENING OF THE CAP. SEVERAL MODELS INCLUDING THE HRRR DEPICT A
GRADUAL UPTICK IN SHOWER AND THUNDERSTORM ACTIVITY THIS
MORNING...MAINLY ACROSS NORTHEAST OKLAHOMA. WILL CARRY THE HIGHEST
POPS IN THIS AREA TODAY WITH MUCH LOWER POPS TO THE SOUTH. ANY
STORMS THAT REMAIN DISCRETE TODAY WILL CARRY A HIGH SEVERE
POTENTIAL.
CONVECTIVE COVERAGE WILL INCREASE OVERNIGHT AS THE UPPER SYSTEM
AND ASSOCIATED COLD FRONT APPROACH THE AREA. A SQUALL LINE WILL
EVENTUALLY DEVELOP ALONG THE COLD FRONT AND SWEEP ACROSS THE AREA
OVERNIGHT. SHOWERS AND STORMS WILL LINGER BEHIND THE FRONT BUT THE
LATEST DATA SUPPORT A QUICKER EXIT TO THE RAIN THURSDAY. THIS
SHOULD ALLOW FOR SOME TEMPERATURE RECOVERY THURSDAY AFTERNOON.
TOTAL RAINFALL AMOUNTS FROM THIS SYSTEM MAY BE NEAR 3 INCHES IN
SOME PLACES...MAINLY IN THE NORTH...SO WILL HAVE TO WATCH THE
FLOODING POTENTIAL ESPECIALLY OVERNIGHT INTO THURSDAY MORNING.
TEMPERATURES WILL DROP TO NEAR OR BELOW FREEZING IN MANY PLACES
THURSDAY NIGHT WITH SOME PLACES LIKELY SEEING THEIR COLDEST
READINGS RECORDED FOR SO LATE IN THE SEASON. APRIL 15TH IS THE
LATESE FREEZE ON RECORD IN MCALESTER AND TULSA HAS NEVER BEEN
COLDER THAN 32 AFTER APRIL 18TH DURING THE PERIOD OF RECORD. A
WARMING TREND WILL TAKE PLACE OVER THE WEEKEND BUT ANOTHER STRONG
COLD FRONT IS SET TO MOVE THROUGH THE AREA EARLY NEXT WEEK. THE
LATEST DATA SUPPORTS A SLOWER FRONTAL PASSAGE SO THE HIGHEST RAIN
CHANCES WILL BE MONDAY NIGHT AND TUESDAY. TEMPERATURES BEHIND THIS
FRONT MAY ONCE AGAIN FLIRT WITH THE FREEZING MARK IN SOME PLACES
BY NEXT WEDNESDAY MORNING.
MADE SOME SIGNIFICANT ADJUSTMENTS TO GUIDANCE TEMPERATURES AGAIN
FOR TONIGHT AND THURSDAY BASED ON THE FORECAST FRONTAL MOVEMENT
AND THE VERIFICATION CUTOFF TIMES...WITH THE SIMILAR ECMWF AND NAM
FOLLOWED ON FRONTAL TIMING.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...99
LONG TERM....99
AVIATION...23
AREA FORECAST DISCUSSION
NWS TULSA OK
422 AM CDT WED APR 17 2013
.DISCUSSION...
FRONTAL BOUNDARY HAS BEGUN TO SLOWLY LIFT NORTH AS A WARM FRONT
AND THE NORTHWARD PROGRESS OF THIS FRONT SHOULD ACCELERATE OVER
THE NEXT FEW HOURS WITH THE ENTIRE FORECAST AREA IN THE WARM
SECTOR BY LATER THIS MORNING. CONVECTIVE EVOLUTION TODAY IS
UNCLEAR WITH A MYRIAD OF SOLUTIONS DEPICTED BY THE VARIOUS MODELS.
LARGE SCALE HEIGHT FALLS WILL BEGIN THIS MORNING AHEAD OF THE
UPPER SYSTEM CURRENTLY IN UTAH AND THIS SHOULD RESULT IN A
WEAKENING OF THE CAP. SEVERAL MODELS INCLUDING THE HRRR DEPICT A
GRADUAL UPTICK IN SHOWER AND THUNDERSTORM ACTIVITY THIS
MORNING...MAINLY ACROSS NORTHEAST OKLAHOMA. WILL CARRY THE HIGHEST
POPS IN THIS AREA TODAY WITH MUCH LOWER POPS TO THE SOUTH. ANY
STORMS THAT REMAIN DISCRETE TODAY WILL CARRY A HIGH SEVERE
POTENTIAL.
CONVECTIVE COVERAGE WILL INCREASE OVERNIGHT AS THE UPPER SYSTEM
AND ASSOCIATED COLD FRONT APPROACH THE AREA. A SQUALL LINE WILL
EVENTUALLY DEVELOP ALONG THE COLD FRONT AND SWEEP ACROSS THE AREA
OVERNIGHT. SHOWERS AND STORMS WILL LINGER BEHIND THE FRONT BUT THE
LATEST DATA SUPPORT A QUICKER EXIT TO THE RAIN THURSDAY. THIS
SHOULD ALLOW FOR SOME TEMPERATURE RECOVERY THURSDAY AFTERNOON.
TOTAL RAINFALL AMOUNTS FROM THIS SYSTEM MAY BE NEAR 3 INCHES IN
SOME PLACES...MAINLY IN THE NORTH...SO WILL HAVE TO WATCH THE
FLOODING POTENTIAL ESPECIALLY OVERNIGHT INTO THURSDAY MORNING.
TEMPERATURES WILL DROP TO NEAR OR BELOW FREEZING IN MANY PLACES
THURSDAY NIGHT WITH SOME PLACES LIKELY SEEING THEIR COLDEST
READINGS RECORDED FOR SO LATE IN THE SEASON. APRIL 15TH IS THE
LATESE FREEZE ON RECORD IN MCALESTER AND TULSA HAS NEVER BEEN
COLDER THAN 32 AFTER APRIL 18TH DURING THE PERIOD OF RECORD. A
WARMING TREND WILL TAKE PLACE OVER THE WEEKEND BUT ANOTHER STRONG
COLD FRONT IS SET TO MOVE THROUGH THE AREA EARLY NEXT WEEK. THE
LATEST DATA SUPPORTS A SLOWER FRONTAL PASSAGE SO THE HIGHEST RAIN
CHANCES WILL BE MONDAY NIGHT AND TUESDAY. TEMPERATURES BEHIND THIS
FRONT MAY ONCE AGAIN FLIRT WITH THE FREEZING MARK IN SOME PLACES
BY NEXT WEDNESDAY MORNING.
MADE SOME SIGNIFICANT ADJUSTMENTS TO GUIDANCE TEMPERATURES AGAIN
FOR TONIGHT AND THURSDAY BASED ON THE FORECAST FRONTAL MOVEMENT
AND THE VERIFICATION CUTOFF TIMES...WITH THE SIMILAR ECMWF AND NAM
FOLLOWED ON FRONTAL TIMING.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 78 43 54 32 / 60 90 50 10
FSM 84 53 65 35 / 30 60 80 10
MLC 81 45 56 32 / 30 70 60 10
BVO 76 40 52 29 / 70 90 40 10
FYV 79 49 56 29 / 40 70 80 10
BYV 80 62 65 30 / 40 60 80 10
MKO 80 45 55 32 / 50 80 70 10
MIO 78 43 52 31 / 70 90 70 10
F10 79 43 55 32 / 40 90 60 10
HHW 83 52 61 36 / 30 60 80 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...23
LONG TERM....05
PLATE
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
241 PM EDT WED APR 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN OVER THE AREA AND MOVE EAST BRINGING A
MOIST SOUTHERLY FLOW THROUGH THURSDAY. A COLD FRONT IS THEN EXPECTED
TO CROSS THE REGION ON FRIDAY AND REACH THE ATLANTIC COAST BY EARLY
SATURDAY. HIGH PRESSURE WILL BUILD OVER THE REGION AGAIN FROM THE
NORTHWEST AND REMAIN IN PLACE THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
AT 215 PM...CONVECTION HAS BECOME MORE WIDESPREAD AS EXPECTED. COLD
POOL...OR BACKDOOR COLD FRONT IF YOU WISH WAS PUSHING S-SE OUT OF
WESTERN NC AND WILL ENTER UPSTATE SC/SOUTHERN NC PIEDMONT BY MID
AFTERNOON. SPC MESO ANAL PAGE SHOWS CAPES INCREASING TO NEAR
1000J/KG FROM FAR WESTERN NC...THROUGH NE GA/UPSTATE SC TOWARD CLT.
EXPECT NUMEROUS SHOWERS/THUNDERSTORMS WILL DEVELOP IN THIS AREA
DURING THE MID/LATE AFTERNOON TIME PERIOD. LAPSE RATES MAY BE
SUFFICENT FOR A FEW STRONG STORMS AND POSSIBLY EVEN ISOLATED SEVERE
STORMS WITH LARGE HAIL/AND OR DAMAGING WINDS. THE HRRR HAS HAD A
DECENT HANDLE ON THE CONVECTIVE TRENDS TODAY SO WILL TREND FORECAST
TOWARD ITS EXPLICIT CONVECTIVE FORECASTS WHICH PUSHES ALL OF THE
CONVECTION THROUGH THE UPSTATE BY ABOUT 00Z WITH SOME LINGERING
SHOWERS CONTINUING INTO THE EVENING NE GA/FAR WESTERN UPSTATE.
FOR THE OVERNIGHT...WILL FASHION THE FORECAST TOWARD THE DRYER 12Z
NAM/CMC REGIONAL AND 00Z ECM. GFS CONTINUES PRECIP OVERNIGHT
APPARENTLY DUE TO ISENTROPIC LIFT OVER COOL POOL ESTABLISHED BY
TODAY`S CONVECTION. WILL BANK ON THE COOL POOL BEING TOO SHALLOW FOR
ENOUGH LIFT TO PRODUCE PRECIP. HOWEVER...EXPECT THAT CLOUD COVER
WILL REMAIN WIDESPREAD OVERNIGHT. MILD TEMPS ARE STILL EXPECTED
OVERNIGHT EVEN WITH THE BACKDOOR FRONTAL PASSAGE. LOWS FROM THE
UPPER 50S TO LOWER 60S ARE FORECAST.
ON THURSDAY...THE CONSENSUS IS THAT IT WILL BE A MUCH QUIETER DAY AS
THE WESTERN ATLANTIC HIGH DOMINATES. ONLY ISOLATED AFTERNOON SHOWERS
AND THUNDRSTORMS AT BEST...AND THOSE WOULD BE MAINLY OVER THE
NORTHERN NC MOUNTAINS/FOOTHILLS. ANOTHE WARM DAY IS IN STORE WITH
HIGHSTOPPING OUT AROUND 80 OUTSIDE THE MOUNTAINS WITH MID 70S
MOUNTAIN VALLEYS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AT 230 PM EST WEDNESDAY...I WILL USE A BLEND OF THE NAM AND GFS FOR
THE PLACEMENT AND TIMING OF THE COLD FRONT. GUIDANCE CONTINUES TO
INDICATE THAT MOIST AND WEAKLY UNSTABLE RETURN FLOW SHOULD SUPPORT
UPSLOPE SHRA ACROSS THE MTNS THURSDAY EVENING INTO FRIDAY MORNING. I
WILL INDICATE SCT SHRA DEVELOPING OVER THE SE FACING MTNS AS EARLY
AS 3Z FRI...EXPANDING TO NUMEROUS SHRA BY SUNRISE FRI. THE BAND OF
SHRA/TSRA SHOULD REACH THE WESTERN NC MTNS BY 15Z...OVER THE CENTRAL
CWA BETWEEN 18-21Z...PUSHING EAST OF THE CWA BY 6Z. I WILL TIME CATE
POPS ACROSS THE CWA TO HIGHLIGHT LATEST MODEL GUIDANCE. HIGHS UNDER
THICK CLOUD COVER AND RAINFALL WILL REMAIN LIMITED...BUT EXPECTED TO
RANGE NEAR NORMAL.
NAM FORECAST SOUNDINGS ALONG AND AHEAD OF THE COLD FRONT CONTINUES
TO INDICATE WEAK INSTABILITY...GENERALLY BETWEEN 200-400 J/KG.
INSTABILITY ACROSS THE MTNS IS EVEN WEAKER. HELICITY VALUES BETWEEN
0-1 KM CONTINUE TO RANGE BETWEEN 200-250 M2/S2. EHI VALUES GENERALLY
REMAIN BELOW .5 M2/S2...HOWEVER...AREAS ACROSS THE I-77 CORRDIOR MAY
PEAK ABOVE 1 M2/S2 DURING THE MID AFTERNOON. THE LOW CAPE/HIGH SHEAR
ENVIRONMENT MAY SUPPORT WELL ORGANIZED LINES OF THUNDERSTORMS.
TIMING AND SHEAR/INSTABILITY VALUES APPEAR TO HAVE THE GREATEST
OVERLAP ACROSS THE PIEDMONT. WE WILL CONTINUE TO HIGHLIGHT THE
SEVERE POTENTIAL IN THE HWO...EMPHASIZING THE RISK FOR DAMAGING WIND
GUSTS.
THE FRONT SHOULD PUSH EAST OVER THE CWA BY LATE FRIDAY EVENING. IN
THE WAKE OF THE FRONT...A DRY AND COOL CANADIAN AIR MASS WILL SPREAD
OVER THE CENTRAL CONUS. MIN TEMPERATURES ARE FORECAST TO FALL A
COUPLE OF DEGREES BELOW NORMAL. RIDGES MAY SEE MID 30S TO NEAR
FREEZING TEMPERATURES BY 12Z SAT. COOL TEMPERATURE PROFILES WILL
REMAIN OVER THE CWA ON SATURDAY. MOS CONSENSUS INDICATES HIGH
TEMPERATURES FORECAST TO RANGE FROM THE L60S ACROSS THE MTNS TO MID
TO UPPER 60S EAST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 2 PM EST WEDNESDAY...THE MEDIUM RANGE FCST PICKS UP AT 00Z ON
SUNDAY WITH THE BROAD UPPER TROF DEAMPLIFYING AS IT LIFTS OVER NEW
ENGLAND AS HEIGHTS RISE OVER THE CAROLINAS. SOME WEAK H5 SHORTWAVE
ACTIVITY WILL PASS TO OUR NORTH ON SUNDAY AND MONDAY AS ANOTHER
LONGWAVE UPPER TROF BEGINS TO DIG DOWN OVER THE ROCKIES. THE TROF
WILL AMPLIFY EARLY NEXT WEEK AS IT APPROACHES THE FCST AREA. BY NEW
DAY 7...THE LONG RANGE MODELS INDICATE THAT THE TROF WILL BE
APPROACHING THE MISS RIVER VALLEY WITH HEIGHTS BEGINNING TO FALL
OVER THE GSP FCST AREA.
AT THE SFC...DRY AND COOL HIGH PRESSURE WILL SPREAD OVER THE REGION
ON SAT AND SUN AS LOW LVL WINDS BECOME NLY AND THEN NELY. THERE IS
SOME DISAGREEMENT WRT THE EVOLUTION OF THE SFC PATTERN ON MON AND
TUES OF NEXT WEEK. THE MODELS AGREE THAT AS THE SFC HIGH SLIDES OFF
THE NEW ENGLAND COAST THAT A WEDGE PATTERN WILL SET UP OVER THE
CAROLINAS. HOWEVER...THE ECMWF TRIES TO DEVELOP A SFC LOW...WITH SIG
WRAP AROUND MOISTURE...OFF THE CAROLINAS COAST ON TUES WHILE THE 12Z
GFS DOES NOT. EITHER WAY...THE NEXT MAJOR FRONTAL SYSTEM WILL
APPROACH THE CWFA BY THE END OF THE PERIOD ON WED AS WINDS BECOME
SELY. FOR THE TIME BEING...I HAVE USED A MORE GFS LIKE SOLUTION FOR
MON AND TUES AND ONLY HAVE A SLIGHT CHANCE POP FOR THAT TIME PERIOD.
POPS RAMP UP TO HIGH END SOLID CHANCE ON WED AS THE FRONT
APPROACHES. TEMPS ARE EXPECTED TO START OUT BELOW NORMAL OVER THE
WEEKEND AND SLOWLY CLIMB TO NEAR NORMAL BY THE END OF THE PERIOD.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...MAIN FOCUS IN THE NEAR TERM IS THUNDERSTORM THREAT AT THE
AIRFIELD. BACKDOOR COLD FRONT MOVING TOWARD THE AREA SHOULD TRIGGER
SCT/NUMEROUS SHOWERS/THUDNERSTORMS AS IT ENCOUNTERS MORE UNSTABLE
AIR VICINITY KCLT. HENCE...HAVE MAINTAINED A TEMPO FOR TSRA FROM 20
TO 22Z. SOMOE MVFR RESTRICTIONS AND GUSTY NW WINDS POSSIBLE WITH
PASSAGE OF THUDNERSTORMS. AFTER THUNDERSTORMS END...EXPECT A VFR SKY
CONDITION FOR THE OVERNIGHT.
ELSEWHERE...JUST LIKE AT KCLT...MAIN ISSUE IS WITH THUNDERSTORMS
THIS AFTERNNON. SHOWERS/TSRA WERE IN TEH VICINITY OF AVL/HKY AT TAF
TIME AND WILL CONTINUE A MENTION IN THE TAK UNTIL ABOUT 22Z. THE SC
AIRFIELDS WILL SEE SCT/NUMEROUS TSRA IN THE 20-23Z TIMEFRAME. EXPECT
STORMS TO DISSIPATE THIS EVENING. THE EXPECTATION IS FOR GENERALLY
VFR SKY CONDITIONS FOR THE OVERNIGHT...BUT HAVE LOWERED CIGS TO MVFR
AT KAVL AS UPSLOPE FLOW DEVELOPS LATE TONIGHT.
OUTLOOK...VFR CONDTIONS ARE EXPECTED FROM THU AFTERNOON THROUGH THU
NIGHT. A COLD FRONT WILL MOVE THROUGH THE REGION FRI...WITH
THUNDERSTORMS AND ASSOCIATED RESTRICTIONS POSSIBLE. DRY HIGH PRES
WILL RETURN OVER THE WEEKEND.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 95% HIGH 95% HIGH 96% HIGH 96%
KGSP HIGH 91% HIGH 95% MED 77% HIGH 98%
KAVL HIGH 95% HIGH 100% HIGH 81% HIGH 90%
KHKY HIGH 100% HIGH 95% HIGH 97% HIGH 95%
KGMU HIGH 91% HIGH 95% MED 77% HIGH 98%
KAND HIGH 100% HIGH 91% MED 79% HIGH 96%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JPT
NEAR TERM...LG
SHORT TERM...NED
LONG TERM...JPT
AVIATION...LG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
142 PM EDT WED APR 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN OVER THE AREA AND MOVE EAST BRINGING A
MOIST SOUTHERLY FLOW THROUGH THURSDAY. A COLD FRONT IS EXPECTED TO
CROSS THE REGION ON FRIDAY AND REACH THE ATLANTIC COAST BY EARLY
SATURDAY. HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTH AND REMAIN
IN PLACE THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 125 PM...SHOWERS/THUNDERSTORMS INCREASING IN COVERAGE AS
BACKDOOR COLD FRONT/COLD POOL MOVES INTO WESTERN NC. CURRENT
FORECAST ESSENTIALLY ON TRACK WITH POPS...BUT MAY HAVE TO MAKE SOME
ADJUSTMENTS TO TEMPS WHERE PRECIP OCCURRING. ATMOSPHERE
DESTABALIZING OVER THE PIEDMONT PER SPC MESOANAL PAGE...SO HRRR IDEA
OF BRING CONVECTION INTO THE PIEDMONT MID/LATE AFTERNOON LOOKS VERY
REASONABLE.
PREVIOUS DISCUSSION:
AS OF 915AM...CURRENT REGIONAL RADARS SHOW A CLUSTER OF SHOWERS/STORMS
OVER NE TN/SW VA AND SE KY MOVING SE. THIS MOVEMENT WILL BRING AT
LEAST SCT SHOWERS/THUNDERSTORMS INTO THE NORTHERN MOUNTAINS THIS
MORNING. THE LATEST HRRR SHOWS NUMEROUS SHOWERS/THUNDERSTORMS
DEVELOPING OVER THE MOUNTAINS AROUND MIDDAY APPARENTLY ACTIONG ON
THE OUTFLOW BOUNDARY FROM THE EARLY MORNING CONVECTION. THE HRRR
THEN MOVES THE CONVECTION INTO THE PIEDMONT BY LATE AFTERNOON. THE
06Z NAM SUPPORTS THIS GENERAL IDEA AS WELL. HENCE...HAVE UPPED POPS
INTO THE NUMEROUS RANGE FOR MOST OF THE MOUNTAINS TODAY WITH
SCATTERED COVERAGE OVER THE PIEDMONT AREAS...EXCEPT ISOLD THE
SOUTHERN UPSTATE. ALSO UPDATED TEMP/DEWPOINT/WIND TRENDS FOR THE
MORNING.
AS OF 7 AM...LINE OF CONVECTION MOVED INTO THE NC MTNS AND BECAME AN
AREA OF SHRA. EXPECT THE SHRA TO MOVE ACROSS THE NRN TIER...AND
POSSIBLY INTO THE SRN NC FOOTHILLS AND PIEDMONT BEFORE DISSIPATING
BY MID MORNING. STILL LOOKS LIKE AT LEAST SCT COVERAGE REDEVELOPS
DURING THE AFTERNOON IN INCREASING INSTABILITY. WE MAY END UP WITH
SCT COVERAGE OVER NE GA/UPSTATE...ESPECIALLY IF AN OUTFLOW BOUNDARY
FROM THE MORNING CONVECTION MOVES THRU. HOWEVER...NOT CONFIDENT ENUF
OT UP POP ATTM.
PREVIOUS DISCUSSION...REGIONAL RADAR CONTINUES TO SHOW MCS
CONVECTION MOVING TOWARD THE AREA FROM NE TN/SW VA. THERE IS A SLY
TRAJECTORY TO THE CONVECTION AND CORFIDI VECTORS INDICATE THE
CONVECTION COULD SLIDE INTO THE NRN MTNS AND FOOTHILLS. HAVE GONE
WITH SCT CONVECTION MOVING INTO THAT AREA...BUT DISSIPATING BEFORE
MOVING OUT OF THE BLUE RIDGE. THE TRAJECTORY OF THE CONVECTION
BEHIND THE INITIAL MCS IS CURRENTLY ENE. THEREFORE...DISSIPATE THE
INITIAL CONVECTION AFTER DAYBREAK... BEFORE DEVELOPING CONVECTION
OVER THE AREA AGAIN DURING THE AFTERNOON AS INSTABILITY DEVELOPS.
THE GUIDANCE IS NOW INDICATING INSTABILITY ACROSS THE NC FOOTHILLS
AND PIEDMONT AS WELL AS THE MTNS. THEREFORE...HAVE UPPED COVERAGE TO
SCT FOR ALL OF NC. KEPT CONVECTION ISOLATED OVER SC AS THERE IS
INSTABILITY THERE...BUT LESS IN THE WAY OF LOW LEVEL FORCING FOR
INCREASED COVERAGE. CANNOT RULE OUT ISOLATED SVR STORMS...MAINLY
ACROSS THE MTNS...WITH LOW WET BULB ZERO LEVELS AND SOME DCAPE
DEVELOPING. HIGHS LOOK TO BE A TAD COOLER THAN PREV FCST...BUT STILL
ABOUT 10 DEGREES ABOVE NORMAL.
CONVECTION WILL LINGER INTO THE EARLY EVENING...BUT DISSIPATE DURING
THE LATE EVENING WITH LOSS OF HEATING. LOW LEVEL SELY FLOW DEVELOPS
OVERNIGHT. WITH CONTINUED COPIOUS LOW LEVEL MOISTURE...EXPECT
ISOLATED SHOWERS TO LINGER ALONG THE BLUE RIDGE EVEN AFTER MIDNIGHT.
THIS WILL ALSO LEAD TO CONTINUED CLOUDINESS. LOWS SHUD BE 10 TO 15
DEGREES ABOVE NORMAL.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
AT 230 AM EST WEDNESDAY...AN UPPER RIDGE WIL BE OFF THE EAST COAST
ON THURSDAY...WITH A TROUGH OVER THE PLAINS. BY FRIDAY MORNING...
THE TROUGH WILL BE OVER THE MS RIVER VALLEY. ON FRIDAY NIGHT THE
TROUGH WILL START TO DEAMPLIFY OVER THE CENTRAL AND SOUTHERN
APPALACHIANS.
A MOIST SOUTHEASTERLY FLOW WILL BE OVER GA AND THE CAROLINAS ON
THURSDAY IN ADVANCE OF A COLD FRONT MOVING INTO THE MS RIVER VALLEY.
THE MODELS SHOW RATHER LIMITED INSTABILITY DURING THE DAY...MAINLY
OVER THE MOUNTAINS AND THE PIEDMONT. AS THE FRONT CROSSES THE TN
RIVER VALLEY FRIDAY NIGHT...MOIST INFLOW INCREASES WITH A TIGHTENING
PRESSURE GRADIENT...SUPPORTING INCREASING POPS. INSTABILITY WILL
WANE IN THE EVENING..THEN INCREASE TOWARD DAYBREAK IN THE
MOUNTAINS...COINCIDING WITH MODERATE SHEAR. BY MIDDAY FRIDAY THE
FRONT WILL BE ALONG THE INTERSTATE 85 CORRIDOR...BY WHICH TIME THE
MODEL SHOW THE BEST INSTABILITY OUT AHEAD OF THE BEST HELICITY...
ALTHOUGH ENOUGH OVERLAP IS PRESENT TO BE OF CONCERN. TEMPERATURES
WILL RUN ABOVE NORMAL AHEAD OF THE FRONT UNTIL FRIDAY...WHEN CLOUDS
AND PRECIPITATION WILL HOLD MAXIMUMS TO AROUND NORMAL.
THE FRONT WILL MOVE EAST OF OUR AREA SATURDAY EVENING...WITH A DRIER
AND COOLER AIR MASS MOVING IN FROM THE WEST OVERNIGHT. ALTHOUGH
MINIMUM TEMPERATURES WILL BE IN THE MID 30S AT HIGHER ELEVATIONS OF
THE NC MOUNTAINS... THE DRIER AIR COMBINED WITH POST FRONTAL WINDS
SHOULD PREVENT FROST FROM FORMING.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AT 230 AM EST WEDNESDAY...THE EASTERN TROUGH WILL CONTINUE TO
DEAMPLIFY OVER THE WEEKEND...WHILE ANOTHER TROUGH SLOWLY AMPLIFIES
OVER THE PLAINS. THE RESULT WILL BE A NEARLY ZONAL FLOW OVER THE
EASTERN TWO THIRDS OF THE NATION. BY MONDAY THE PATTERN AMPLIFIES...
WITH AN EAST COAST RIDGE AND CENTRAL USA TROUGH. ON TUESDAY THE
TROUGH MOVES OFF THE EAST COAST...AND THE RIDGE UPSTREAM REACHES THE
MS RIVER VALLEY.
SATURDAY AND SUNDAY FEATURE DRY HIGH PRESSURE MOVING ACROSS THE
APPALACHIANS. BY MONDAY THIS SURFACE HIGH WILL EXTEND ALONG THE
EASTERN SEABOARD...WHILE THE OLD SURFACE FRONT WILL BE STALED NEAR
THE GULF COAST. ISENTROPIC UPGLIDE OVER THIS BOUNDARY WILL SPREAD
CLOUDS AND PRECIPITATION NORTH ACROSS OUR AREA. THE SURFACE RIDGE
WEAKENS ON TUESDAY...WHILE ANOTHER COLD FRONT WILL MOVE INTO THE TN
RIVER VALLEY FORM THE WEST. MAXIMUM TEMPERATURES WILL RUN AROUND SIX
OR SEVEN DEGREES BELOW NORMAL FROM SATURDAY THROUGH TUESDAY....WHILE
MINIMUM TEMPERATURES RUN AROUND NORMAL.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...MAIN FOCUS IN THE NEAR TERM IS THUNDERSTORM THREAT AT THE
AIRFIELD. BACKDOOR COLD FRONT MOVING TOWARD THE AREA SHOULD TRIGGER
SCT/NUMEROUS SHOWERS/THUDNERSTORMS AS IT ENCOUNTERS MORE UNSTABLE
AIR VICINITY KCLT. HENCE...HAVE MAINTAINED A TEMPO FOR TSRA FROM 20
TO 22Z. SOMOE MVFR RESTRICTIONS AND GUSTY NW WINDS POSSIBLE WITH
PASSAGE OF THUDNERSTORMS. AFTER THUNDERSTORMS END...EXPECT A VFR SKY
CONDITION FOR THE OVERNIGHT.
ELSEWHERE...JUST LIKE AT KCLT...MAIN ISSUE IS WITH THUNDERSTORMS
THIS AFTERNNON. SHOWERS/TSRA WERE IN TEH VICINITY OF AVL/HKY AT TAF
TIME AND WILL CONTINUE A MENTION IN THE TAK UNTIL ABOUT 22Z. THE SC
AIRFIELDS WILL SEE SCT/NUMEROUS TSRA IN THE 20-23Z TIMEFRAME. EXPECT
STORMS TO DISSIPATE THIS EVENING. THE EXPECTATION IS FOR GENERALLY
VFR SKY CONDITIONS FOR THE OVERNIGHT...BUT HAVE LOWERED CIGS TO MVFR
AT KAVL AS UPSLOPE FLOW DEVELOPS LATE TONIGHT.
OUTLOOK...VFR CONDTIONS ARE EXPECTED FROM THU AFTERNOON THROUGH THU
NIGHT. A COLD FRONT WILL MOVE THROUGH THE REGION FRI...WITH
THUNDERSTORMS AND ASSOCIATED RESTRICTIONS POSSIBLE. DRY HIGH PRES
WILL RETURN OVER THE WEEKEND.
CONFIDENCE TABLE...
17-23Z 23-05Z 05-11Z 11-17Z
KCLT HIGH 100% HIGH 100% HIGH 96% HIGH 90%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 90%
KAVL HIGH 100% HIGH 100% HIGH 94% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 96% MED 65%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 90%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 87%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JAT
NEAR TERM...LG
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...LG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1058 AM EDT WED APR 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN OVER THE AREA AND MOVE EAST BRINGING A
MOIST SOUTHERLY FLOW THROUGH THURSDAY. A COLD FRONT IS EXPECTED TO
CROSS THE REGION ON FRIDAY AND REACH THE ATLANTIC COAST BY EARLY
SATURDAY. HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTH AND REMAIN
IN PLACE THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 EDT...CONVECTIVE CLUSTER OVER NE TN/SE KY HAS ENTERED NW
CAROLINA AND CONTINUES TO MOVE SE. LATEST HRRR CONTINUES TO LATCH
ONTO TO THIS CONVECTION AND MOVE/DEVELOP NUMEROUS CONVECTIVE CELLS
ACROSS THE NC MOUNTAINS IN THE EARLY TO MID AFTENROON HOURS...AND
THEN INTO THE PIEDMONT MID TO LATE AFTERNOON. MADE SOME ADJUSTMENTS
TO POP GRID TO INCREASE COVERAGE AND TWEAK TIMING.
PREVIOUS DISCUSSION:
AS OF 915AM...CURRENT REGIONAL RADARS SHOW A CLUSTER OF
SHOWERS/STORMS OVER NE TN/SW VA AND SE KY MOVING SE. THIS MOVEMENT
WILL BRING AT LEAST SCT SHOWERS/THUNDERSTORMS INTO THE NORTHERN
MOUNTAINS THIS MORNING. THE LATEST HRRR SHOWS NUMEROUS
SHOWERS/THUNDERSTORMS DEVELOPING OVER THE MOUNTAINS AROUND MIDDAY
APPARENTLY ACTIONG ON THE OUTFLOW BOUNDARY FROM THE EARLY MORNING
CONVECTION. THE HRRR THEN MOVES THE CONVECTION INTO THE PIEDMONT BY
LATE AFTERNOON. THE 06Z NAM SUPPORTS THIS GENERAL IDEA AS WELL.
HENCE...HAVE UPPED POPS INTO THE NUMEROUS RANGE FOR MOST OF THE
MOUNTAINS TODAY WITH SCATTERED COVERAGE OVER THE PIEDMONT
AREAS...EXCEPT ISOLD THE SOUTHERN UPSTATE. ALSO UPDATED
TEMP/DEWPOINT/WIND TRENDS FOR THE MORNING.
CANNOT RULE OUT ISOLATED SVR STORMS...MAINLY ACROSS THE MTNS...WITH
LOW WET BULB ZERO LEVELS AND SOME DCAPE DEVELOPING. HIGHS LOOK TO BE
A TAD COOLER THAN PREV FCST...BUT STILL ABOUT 10 DEGREES ABOVE
NORMAL.
CONVECTION WILL LINGER INTO THE EARLY EVENING...BUT DISSIPATE DURING
THE LATE EVENING WITH LOSS OF HEATING. LOW LEVEL SELY FLOW DEVELOPS
OVERNIGHT. WITH CONTINUED COPIOUS LOW LEVEL MOISTURE...EXPECT
ISOLATED SHOWERS TO LINGER ALONG THE BLUE RIDGE EVEN AFTER MIDNIGHT.
THIS WILL ALSO LEAD TO CONTINUED CLOUDINESS. LOWS SHUD BE 10 TO 15
DEGREES ABOVE NORMAL.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AT 230 AM EST WEDNESDAY...AN UPPER RIDGE WIL BE OFF THE EAST COAST
ON THURSDAY...WITH A TROUGH OVER THE PLAINS. BY FRIDAY MORNING...
THE TROUGH WILL BE OVER THE MS RIVER VALLEY. ON FRIDAY NIGHT THE
TROUGH WILL START TO DEAMPLIFY OVER THE CENTRAL AND SOUTHERN
APPALACHIANS.
A MOIST SOUTHEASTERLY FLOW WILL BE OVER GA AND THE CAROLINAS ON
THURSDAY IN ADVANCE OF A COLD FRONT MOVING INTO THE MS RIVER VALLEY.
THE MODELS SHOW RATHER LIMITED INSTABILITY DURING THE DAY...MAINLY
OVER THE MOUNTAINS AND THE PIEDMONT. AS THE FRONT CROSSES THE TN
RIVER VALLEY FRIDAY NIGHT...MOIST INFLOW INCREASES WITH A TIGHTENING
PRESSURE GRADIENT...SUPPORTING INCREASING POPS. INSTABILITY WILL
WANE IN THE EVENING..THEN INCREASE TOWARD DAYBREAK IN THE
MOUNTAINS...COINCIDING WITH MODERATE SHEAR. BY MIDDAY FRIDAY THE
FRONT WILL BE ALONG THE INTERSTATE 85 CORRIDOR...BY WHICH TIME THE
MODEL SHOW THE BEST INSTABILITY OUT AHEAD OF THE BEST HELICITY...
ALTHOUGH ENOUGH OVERLAP IS PRESENT TO BE OF CONCERN. TEMPERATURES
WILL RUN ABOVE NORMAL AHEAD OF THE FRONT UNTIL FRIDAY...WHEN CLOUDS
AND PRECIPITATION WILL HOLD MAXIMUMS TO AROUND NORMAL.
THE FRONT WILL MOVE EAST OF OUR AREA SATURDAY EVENING...WITH A DRIER
AND COOLER AIR MASS MOVING IN FROM THE WEST OVERNIGHT. ALTHOUGH
MINIMUM TEMPERATURES WILL BE IN THE MID 30S AT HIGHER ELEVATIONS OF
THE NC MOUNTAINS... THE DRIER AIR COMBINED WITH POST FRONTAL WINDS
SHOULD PREVENT FROST FROM FORMING.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AT 230 AM EST WEDNESDAY...THE EASTERN TROUGH WILL CONTINUE TO
DEAMPLIFY OVER THE WEEKEND...WHILE ANOTHER TROUGH SLOWLY AMPLIFIES
OVER THE PLAINS. THE RESULT WILL BE A NEARLY ZONAL FLOW OVER THE
EASTERN TWO THIRDS OF THE NATION. BY MONDAY THE PATTERN AMPLIFIES...
WITH AN EAST COAST RIDGE AND CENTRAL USA TROUGH. ON TUESDAY THE
TROUGH MOVES OFF THE EAST COAST...AND THE RIDGE UPSTREAM REACHES THE
MS RIVER VALLEY.
SATURDAY AND SUNDAY FEATURE DRY HIGH PRESSURE MOVING ACROSS THE
APPALACHIANS. BY MONDAY THIS SURFACE HIGH WILL EXTEND ALONG THE
EASTERN SEABOARD...WHILE THE OLD SURFACE FRONT WILL BE STALED NEAR
THE GULF COAST. ISENTROPIC UPGLIDE OVER THIS BOUNDARY WILL SPREAD
CLOUDS AND PRECIPITATION NORTH ACROSS OUR AREA. THE SURFACE RIDGE
WEAKENS ON TUESDAY...WHILE ANOTHER COLD FRONT WILL MOVE INTO THE TN
RIVER VALLEY FORM THE WEST. MAXIMUM TEMPERATURES WILL RUN AROUND SIX
OR SEVEN DEGREES BELOW NORMAL FROM SATURDAY THROUGH TUESDAY....WHILE
MINIMUM TEMPERATURES RUN AROUND NORMAL.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...WIDESPREAD STRATOCU DID NOT DEVELOP. HOWEVER...EXPECT SCT
LOW VFR WITH BKN HIGHER CLOUDS THIS MORNING AS CONVECTIVE DEBRIS
FROM THE DYING CONVECTION TO THE NW MOVES OVERHEAD. DO NOT EXPECT
THIS CONVECTION TO AFFECT THE AIRFIELD...CANNOT RULE OUT SOME
SPRINKLES THIS MORNING. OTHERWISE...LOW VFR SHUD DEVELOP DURING THE
AFTERNOON. GUIDANCE STILL SUGGESTS BETTER CHC OF CONVECTION OVER THE
PIEDMONT THIS AFTERNOON. THEREFORE...HAVE INCLUDED A PROB30 FOR LATE
AFTERNOON/EARLY EVENING. CONVECTION SHUD DIE OFF DURING THE
EVENING...BUT LOW VFR CONTINUES OVERNIGHT. HAVE KEPT IT AT VFR FOR
NOW EVEN THO SOME GUIDANCE SUGGESTING LOWER CIGS. SWLY WINDS BECOME
SLY THRU THE DAY AND SELY OVERNIGHT.
ELSEWHERE...JUST LIKE AT KCLT...WIDESPREAD STRATOCU DID NOT DEVELOP
BUT NEITHER DID FOG. HAVE INCLUDED EARLY PRECIP AT KAVL/KHKY TO
ACCOUNT FOR THE CURRENT CONVECTION. HOWEVER...DO NOT EXPECT ANY
RESTRICTIONS...BUT WOULD BE BRIEF IF THEY DID DEVELOP. STILL EXPECT
BETTER CHC OF CONVECTION AT KHKY/KAVL WITH ONLY SLIGHT CHC OVER THE
SC SITES. KEPT THE PROB30 GOING FOR KHKY/KAVL. CONVECTION SHUD
DIMINISH DURING THE EVENING...BUT LOW LEVEL SELY FLOW COULD KEEP
ISOLATED SHRA GOING ALONG THE BLUE RIDGE. DO NOT EXPECT ANY
RESTRICTIONS EXCEPT NEAR CONVECTION UNTIL OVERNIGHT NEAR THE BLUE
RIDGE WITH THE MOIST SELY FLOW. THEREFORE...DID BRING MVFR TO KAVL
BY MORNING. GENERALLY SWLY FLOW BECOMES SLY THEN SELY THRU THE
PERIOD.
OUTLOOK...SOUTHERLY FLOW WILL INCREASE ACROSS THE AREA ON THU. A
COLD FRONT WILL MOVE THROUGH THE REGION FRI...WITH THUNDERSTORMS AND
ASSOCIATED RESTRICTIONS POSSIBLE. DRY HIGH PRES WILL RETURN OVER THE
WEEKEND.
CONFIDENCE TABLE...
15-21Z 21-03Z 03-09Z 09-15Z
KCLT HIGH 100% HIGH 100% HIGH 98% HIGH 90%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 80%
KAVL HIGH 100% HIGH 100% HIGH 98% HIGH 87%
KHKY HIGH 100% HIGH 100% HIGH 98% MED 72%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 80%
KAND HIGH 100% HIGH 100% HIGH 98% HIGH 90%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JAT
NEAR TERM...LG
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...RWH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
919 AM EDT WED APR 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN OVER THE AREA AND MOVE EAST BRINGING A
MOIST SOUTHERLY FLOW THROUGH THURSDAY. A COLD FRONT IS EXPECTED TO
CROSS THE REGION ON FRIDAY AND REACH THE ATLANTIC COAST BY EARLY
SATURDAY. HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTH AND REMAIN
IN PLACE THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 915AM...CURRENT REGIONAL RADARS SHOW A CLUSTER OF SHOWERS/STORMS
OVER NE TN/SW VA AND SE KY MOVING SE. THIS MOVEMENT WILL BRING AT
LEAST SCT SHOWERS/THUNDERSTORMS INTO THE NORTHERN MOUNTAINS THIS
MORNING. THE LATEST HRRR SHOWS NUMEROUS SHOWERS/THUNDERSTORMS
DEVELOPING OVER THE MOUNTAINS AROUND MIDDAY APPARENTLY ACTING ON
THE OUTFLOW BOUNDARY FROM THE EARLY MORNING CONVECTION. THE HRRR
THEN MOVES THE CONVECTION INTO THE PIEDMONT BY LATE AFTERNOON. THE
06Z NAM SUPPORTS THIS GENERAL IDEA AS WELL. HENCE...HAVE UPPED
POPS INTO THE NUMEROUS RANGE FOR MOST OF THE MOUNTAINS TODAY WITH
SCATTERED COVERAGE OVER THE PIEDMONT AREAS...EXCEPT ISOLD THE
SOUTHERN UPSTATE. ALSO UPDATED TEMP/DEWPOINT/WIND TRENDS FOR THE
MORNING.
PREVIOUS DISCUSSION:
AS OF 7 AM...LINE OF CONVECTION MOVED INTO THE NC MTNS AND BECAME AN
AREA OF SHRA. EXPECT THE SHRA TO MOVE ACROSS THE NRN TIER...AND
POSSIBLY INTO THE SRN NC FOOTHILLS AND PIEDMONT BEFORE DISSIPATING
BY MID MORNING. STILL LOOKS LIKE AT LEAST SCT COVERAGE REDEVELOPS
DURING THE AFTERNOON IN INCREASING INSTABILITY. WE MAY END UP WITH
SCT COVERAGE OVER NE GA/UPSTATE...ESPECIALLY IF AN OUTFLOW BOUNDARY
FROM THE MORNING CONVECTION MOVES THRU. HOWEVER...NOT CONFIDENT ENUF
OT UP POP ATTM.
PREVIOUS DISCUSSION...REGIONAL RADAR CONTINUES TO SHOW MCS
CONVECTION MOVING TOWARD THE AREA FROM NE TN/SW VA. THERE IS A SLY
TRAJECTORY TO THE CONVECTION AND CORFIDI VECTORS INDICATE THE
CONVECTION COULD SLIDE INTO THE NRN MTNS AND FOOTHILLS. HAVE GONE
WITH SCT CONVECTION MOVING INTO THAT AREA...BUT DISSIPATING BEFORE
MOVING OUT OF THE BLUE RIDGE. THE TRAJECTORY OF THE CONVECTION
BEHIND THE INITIAL MCS IS CURRENTLY ENE. THEREFORE...DISSIPATE THE
INITIAL CONVECTION AFTER DAYBREAK... BEFORE DEVELOPING CONVECTION
OVER THE AREA AGAIN DURING THE AFTERNOON AS INSTABILITY DEVELOPS.
THE GUIDANCE IS NOW INDICATING INSTABILITY ACROSS THE NC FOOTHILLS
AND PIEDMONT AS WELL AS THE MTNS. THEREFORE...HAVE UPPED COVERAGE TO
SCT FOR ALL OF NC. KEPT CONVECTION ISOLATED OVER SC AS THERE IS
INSTABILITY THERE...BUT LESS IN THE WAY OF LOW LEVEL FORCING FOR
INCREASED COVERAGE. CANNOT RULE OUT ISOLATED SVR STORMS...MAINLY
ACROSS THE MTNS...WITH LOW WET BULB ZERO LEVELS AND SOME DCAPE
DEVELOPING. HIGHS LOOK TO BE A TAD COOLER THAN PREV FCST...BUT STILL
ABOUT 10 DEGREES ABOVE NORMAL.
CONVECTION WILL LINGER INTO THE EARLY EVENING...BUT DISSIPATE DURING
THE LATE EVENING WITH LOSS OF HEATING. LOW LEVEL SELY FLOW DEVELOPS
OVERNIGHT. WITH CONTINUED COPIOUS LOW LEVEL MOISTURE...EXPECT
ISOLATED SHOWERS TO LINGER ALONG THE BLUE RIDGE EVEN AFTER MIDNIGHT.
THIS WILL ALSO LEAD TO CONTINUED CLOUDINESS. LOWS SHUD BE 10 TO 15
DEGREES ABOVE NORMAL.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AT 230 AM EST WEDNESDAY...AN UPPER RIDGE WIL BE OFF THE EAST COAST
ON THURSDAY...WITH A TROUGH OVER THE PLAINS. BY FRIDAY MORNING...
THE TROUGH WILL BE OVER THE MS RIVER VALLEY. ON FRIDAY NIGHT THE
TROUGH WILL START TO DEAMPLIFY OVER THE CENTRAL AND SOUTHERN
APPALACHIANS.
A MOIST SOUTHEASTERLY FLOW WILL BE OVER GA AND THE CAROLINAS ON
THURSDAY IN ADVANCE OF A COLD FRONT MOVING INTO THE MS RIVER VALLEY.
THE MODELS SHOW RATHER LIMITED INSTABILITY DURING THE DAY...MAINLY
OVER THE MOUNTAINS AND THE PIEDMONT. AS THE FRONT CROSSES THE TN
RIVER VALLEY FRIDAY NIGHT...MOIST INFLOW INCREASES WITH A TIGHTENING
PRESSURE GRADIENT...SUPPORTING INCREASING POPS. INSTABILITY WILL
WANE IN THE EVENING..THEN INCREASE TOWARD DAYBREAK IN THE
MOUNTAINS...COINCIDING WITH MODERATE SHEAR. BY MIDDAY FRIDAY THE
FRONT WILL BE ALONG THE INTERSTATE 85 CORRIDOR...BY WHICH TIME THE
MODEL SHOW THE BEST INSTABILITY OUT AHEAD OF THE BEST HELICITY...
ALTHOUGH ENOUGH OVERLAP IS PRESENT TO BE OF CONCERN. TEMPERATURES
WILL RUN ABOVE NORMAL AHEAD OF THE FRONT UNTIL FRIDAY...WHEN CLOUDS
AND PRECIPITATION WILL HOLD MAXIMUMS TO AROUND NORMAL.
THE FRONT WILL MOVE EAST OF OUR AREA SATURDAY EVENING...WITH A DRIER
AND COOLER AIR MASS MOVING IN FROM THE WEST OVERNIGHT. ALTHOUGH
MINIMUM TEMPERATURES WILL BE IN THE MID 30S AT HIGHER ELEVATIONS OF
THE NC MOUNTAINS... THE DRIER AIR COMBINED WITH POST FRONTAL WINDS
SHOULD PREVENT FROST FROM FORMING.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AT 230 AM EST WEDNESDAY...THE EASTERN TROUGH WILL CONTINUE TO
DEAMPLIFY OVER THE WEEKEND...WHILE ANOTHER TROUGH SLOWLY AMPLIFIES
OVER THE PLAINS. THE RESULT WILL BE A NEARLY ZONAL FLOW OVER THE
EASTERN TWO THIRDS OF THE NATION. BY MONDAY THE PATTERN AMPLIFIES...
WITH AN EAST COAST RIDGE AND CENTRAL USA TROUGH. ON TUESDAY THE
TROUGH MOVES OFF THE EAST COAST...AND THE RIDGE UPSTREAM REACHES THE
MS RIVER VALLEY.
SATURDAY AND SUNDAY FEATURE DRY HIGH PRESSURE MOVING ACROSS THE
APPALACHIANS. BY MONDAY THIS SURFACE HIGH WILL EXTEND ALONG THE
EASTERN SEABOARD...WHILE THE OLD SURFACE FRONT WILL BE STALED NEAR
THE GULF COAST. ISENTROPIC UPGLIDE OVER THIS BOUNDARY WILL SPREAD
CLOUDS AND PRECIPITATION NORTH ACROSS OUR AREA. THE SURFACE RIDGE
WEAKENS ON TUESDAY...WHILE ANOTHER COLD FRONT WILL MOVE INTO THE TN
RIVER VALLEY FORM THE WEST. MAXIMUM TEMPERATURES WILL RUN AROUND SIX
OR SEVEN DEGREES BELOW NORMAL FROM SATURDAY THROUGH TUESDAY....WHILE
MINIMUM TEMPERATURES RUN AROUND NORMAL.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...WIDESPREAD STRATOCU DID NOT DEVELOP. HOWEVER...EXPECT SCT
LOW VFR WITH BKN HIGHER CLOUDS THIS MORNING AS CONVECTIVE DEBRIS
FROM THE DYING CONVECTION TO THE NW MOVES OVERHEAD. DO NOT EXPECT
THIS CONVECTION TO AFFECT THE AIRFIELD...CANNOT RULE OUT SOME
SPRINKLES THIS MORNING. OTHERWISE...LOW VFR SHUD DEVELOP DURING THE
AFTERNOON. GUIDANCE STILL SUGGESTS BETTER CHC OF CONVECTION OVER THE
PIEDMONT THIS AFTERNOON. THEREFORE...HAVE INCLUDED A PROB30 FOR LATE
AFTERNOON/EARLY EVENING. CONVECTION SHUD DIE OFF DURING THE
EVENING...BUT LOW VFR CONTINUES OVERNIGHT. HAVE KEPT IT AT VFR FOR
NOW EVEN THO SOME GUIDANCE SUGGESTING LOWER CIGS. SWLY WINDS BECOME
SLY THRU THE DAY AND SELY OVERNIGHT.
ELSEWHERE...JUST LIKE AT KCLT...WIDESPREAD STRATOCU DID NOT DEVELOP
BUT NEITHER DID FOG. HAVE INCLUDED EARLY PRECIP AT KAVL/KHKY TO
ACCOUNT FOR THE CURRENT CONVECTION. HOWEVER...DO NOT EXPECT ANY
RESTRICTIONS...BUT WOULD BE BRIEF IF THEY DID DEVELOP. STILL EXPECT
BETTER CHC OF CONVECTION AT KHKY/KAVL WITH ONLY SLIGHT CHC OVER THE
SC SITES. KEPT THE PROB30 GOING FOR KHKY/KAVL. CONVECTION SHUD
DIMINISH DURING THE EVENING...BUT LOW LEVEL SELY FLOW COULD KEEP
ISOLATED SHRA GOING ALONG THE BLUE RIDGE. DO NOT EXPECT ANY
RESTRICTIONS EXCEPT NEAR CONVECTION UNTIL OVERNIGHT NEAR THE BLUE
RIDGE WITH THE MOIST SELY FLOW. THEREFORE...DID BRING MVFR TO KAVL
BY MORNING. GENERALLY SWLY FLOW BECOMES SLY THEN SELY THRU THE
PERIOD.
OUTLOOK...SOUTHERLY FLOW WILL INCREASE ACROSS THE AREA ON THU. A
COLD FRONT WILL MOVE THROUGH THE REGION FRI...WITH THUNDERSTORMS AND
ASSOCIATED RESTRICTIONS POSSIBLE. DRY HIGH PRES WILL RETURN OVER THE
WEEKEND.
CONFIDENCE TABLE...
13-19Z 19-01Z 01-07Z 07-13Z
KCLT HIGH 99% HIGH 100% HIGH 100% HIGH 98%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 91%
KAVL HIGH 100% HIGH 100% HIGH 98% HIGH 88%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 86%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 90%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 91%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JAT
NEAR TERM...LG
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...RWH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1244 PM CDT WED APR 17 2013
.UPDATE...
ISSUED AT 1042 AM CDT WED APR 17 2013
MADE A BIT OF A MODIFICATION TO THE WINTER WEATHER ADVISORY IN
THAT WE POSTPONED THE START OF THE ADVISORY FOR MUCH OF OUR
WESTERN ZONES UNTIL 00Z THIS EVENING. WE DID KEEP IT AS IS FOR
GREGORY AND BRULE COUNTIES...PRIMARILY FOR THE THREAT OF LIGHT
FREEZING DRIZZLE. WINNER CONTINUES TO REPORT SOME SORT OF LIGHT
MIXED PRECIPITATION...AND TEMPERATURES SO FAR IN SOUTH CENTRAL SD
ARE BELOW FREEZING. THAT SAID...CHAMBERLAIN AND SURROUNDING
VICINITY MAY WARM UP TO JUST ABOVE FREEZING THIS AFTERNOON. BUT
SOME EXISTING SNOW COVER IN THOSE AREAS...THE ACTUAL GROUND
TEMPERATURE MAY BE A BIT COOLER ALLOWING ANY DRIZZLE TO PARTIALLY
FREEZE ON CONTACT.
OTHERWISE...THE WARM AIR ADVECTION WHICH HELPED TO CAUSE THE
PRECIPITATION THIS MORNING IN NORTHWEST IOWA IS EXITING AT THIS
TIME. THEREFORE A BULK OF OUR FORECAST AREA IS LEFT WITH MOISTURE
STARVED MID LEVELS...SEEN BEST ON THE RAP SOUNDINGS. THERE IS SNOW
TO THE WEST OF OUR FORECAST AREA WHERE 650MB FRONTOGENESIS IS
MAXIMIZED AND WHERE THERE IS MID LEVEL MOISTURE. HOWEVER IN OUR
FORECAST AREA...THE MAXIMIZED FRONTOGENESIS IS LOWER...AROUND
750MB TO 700MB...AND CONDITIONS ARE QUITE DRY IN THAT LAYER
THROUGH MUCH OF THE AFTERNOON. IN FACT IN OUR SOUTHEAST ZONES...
THE FRONTOGENESIS WAS IN THE LOWER LEVELS EARLIER TODAY...AND THAT
TOO IS TEMPORARILY WANING. SO THINKING OF LOWERING POPS IN MANY
AREAS UNTIL 21Z AND INCLUDE DRIZZLE...THEN BEGIN TO RAMP UP THE
POPS AGAIN LATE THIS AFTERNOON AS THE NEXT WELL ADVERTISED STRONG
WAVE APPROACHES.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CDT WED APR 17 2013
COMPLEX SET UP THIS MORNING WITH A COUPLE OF AREAS OF PRECIPITATION.
THE FIRST WAS A SNOW BAND THAT WAS VERY SLOWLY WORKING EAST INTO THE
FAR WESTERN CWA THIS MORNING. THE SOUTH AND EAST EDGE OF THIS BAND
HAS REALLY STRUGGLED TO DEVELOP BUT SOME HINTS THAT THERE WILL BE
SOME DEVELOPMENT THROUGH THE MORNING INTO THE WESTERN CWA. THE
SECOND AREA WAS ASSOCIATED WITH A POTENT AREA OF THETA E ADVECTION
AND MODERATE INSTABILITY ACROSS KANSAS. EXPECT THIS AREA TO
CONTINUE TO DEVELOP NORTHEAST THROUGH THE EARLY MORNING HOURS AND
CLIP THE SOUTHEAST THIRD OF THE CWA. WILL HAVE THUNDER OVER PARTS OF
NORTHWEST IOWA WITH DECENT ELEVATED INSTABILITY BUT NOT THINKING
SEVERE. INCREASED QPF AMOUNTS A BIT IN THESE AREAS AS WELL TO AROUND
A QUARTER TO THREE QUARTERS OF AN INCH THIS MORNING. IN BETWEEN
THESE TWO AREAS OVER EAST CENTRAL SOUTH DAKOTA AND SOUTHWEST
MINNESOTA THE POTENTIAL FOR NOT TOO MUCH ACTIVITY AS THE BAND OF
SNOW LOCKS UP TOT HE EAST TODAY AND THE CONVECTIVE ELEMENTS REMAIN
MAINLY SOUTH AND EAST. HOWEVER...ONCE THE UPPER LEVEL SUPPORT MOVES
INTO NEBRASKA TONIGHT EXPECT THIS RELATIVE BLANK SPOT TO FILL IN
QUICKLY THIS EVENING. SUSPECT MAINLY RAIN IN THE EASTERN CWA WHILE
THE WEST WILL BE MAINLY SNOW.
TONIGHT INTO THURSDAY POSES A PROBLEM FOR THE AREA WITH
FAIRLY GOOD AGREEMENT AMONGST THE VARIOUS MODELS DYNAMICALLY. THEY
ALL AGREE IN SWINGING THE STRONGEST PV ADVECTION NORTHWARD LATE
WEDNESDAY NIGHT INTO SOUTHEAST SOUTH DAKOTA THEN SHIFT IT EAST
GRADUALLY THROUGH THE DAY THURSDAY. IN FACT MEASURABLE SNOWFALL IS
PRETTY LIKELY IN THE EASTERN CWA THURSDAY EVENING. IT APPEARS THAT
THERE WILL BE A VERY STRONG MID LEVEL BOUNDARY IN PLACE WHICH WILL
COME NORTH THIS MORNING WITH THE STRONG LOW AND MID LEVEL THETA E
ADVECTION. THIS WAVE WILL BE ABLE TO INTERACT WITH THIS THERMAL
BOUNDARY AND IF THE SOUNDINGS ARE CORRECT SOMETHING CLOSE TO THE
750MB FRONT WILL YIELD THE MOST POTENT PRECIPITATION RATES AS A
PARCEL LIFTED FROM THIS LEVEL WOULD HAVE ABOUT 150 TO 300 J/KG
UNCAPPED CAPE TO WORK WITH. THERE MAY BE A SMALL RIBBON OF SLEET OR
FREEZING RAIN FROM ABOUT 22Z THROUGH 5Z BUT THIS LOOKS TO BE MORE OF
A TRANSITIONAL ISSUE VERSUS LAST WEEKS SUSTAINED PERIOD OF SLEET AND
FREEZING RAIN. SO FOR NOW NOT PLANNING ON ANY MAJOR ICE PROBLEMS AND
ONLY A BRIEF PERIOD FOR 1 TO 2 HOURS FROM ABOUT INTERSTATE 29 EAST
VERY LATE THIS AFTERNOON AND THIS EVENING. FAIRLY CONSISTENT SIGNALS
FROM THE MODELS THAT FROM ABOUT 0Z THURSDAY THROUGH 0Z FRIDAY A HALF
TO THREE QUARTERS OF AN INCH OF LIQUID WILL BE LIKELY AND MOST OF
THIS WILL FALL AS SNOW...AGAIN POSSIBLY A LITTLE SLEET TO START.
SUSPECT SNOWFALL RATIOS WILL BE LIMITED AND WILL AIM FOR AN AVERAGE
OF ABOUT 9:1 THROUGH THE EVENT...ALTHOUGH SOMETHING CLOSE TO 12:1
WILL BE POSSIBLE THURSDAY AFTERNOON. WILL ISSUE AN ADVISORY FOR
SOUTHWEST MINNESOTA INTO SOUTHEAST SOUTH DAKOTA FOR THE EXPECTED
SNOW TONIGHT INTO THURSDAY. BORDERLINE WARNING CRITERIA BUT WITH A
WET SNOW AND MELTING/COMPACTION POTENTIAL WILL LEAN TOWARDS A HIGH
END ADVISORY.
THE SNOW SHOULD WIND DOWN THURSDAY NIGHT WITH FRIDAY JUST LOOKING
WINDY AND COLD. TEMPERATURES FROM TODAY INTO FRIDAY SHOULD BE ABOUT
20 TO 25 DEGREES BELOW NORMAL.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 329 AM CDT WED APR 17 2013
THIS WEEKEND INTO EARLY NEXT WEEK SHOULD SEE CONTINUED BELOW NORMAL
TEMPERATURES WITH TROUGHING REMAINING OVER THE CENTRAL US. WAVE
MOVING THROUGH SATURDAY NIGHT INTO SUNDAY SHOULD BRING AT LEAST
SCATTERED SHOWERS TO THE AREA...THERMAL PROFILES LOOK WARM ENOUGH FOR
ANY PRECIP TO BE RAIN WITH THIS WAVE. HIGHS SATURDAY SHOULD MAINLY
BE IN THE 40S...COULD SEE SOME 50S ON SUNDAY AHEAD OF THE
APPROACHING COLD FRONT. THE FRONT PUSHES THROUGH SUNDAY NIGHT INTO
MONDAY RESULTING IN HIGHS BACK INTO THE 40S FOR EARLY NEXT WEEK.
RAIN SHOWER CHANCES CONTINUE SUNDAY NIGHT INTO MONDAY WITH THIS
FRONTAL PASSAGE AND DIGGING WAVE. THERMAL PROFILES SUGGEST BY LATER
MONDAY ANYTHING THAT FALLS COULD BE SNOW. HOWEVER MODELS DIFFER ON
THEIR HANDLING OF THE DIGGING WAVE...WITH THE LATEST 0Z ECMWF THE
MOST AGGRESSIVE WITH THE SYSTEM...CUTTING THE LOW OFF TO OUR SOUTH AND
GIVING PORTIONS OF OUR CWA SNOW OR RAIN ON TUESDAY. THIS IS AN
OUTLIER SOLUTION AT THIS TIME...WITH THE MORE LIKELY RESULT BEING A
MORE PROGRESSIVE WAVE AND JUST LIGHTER QPF AMOUNTS SUNDAY NIGHT INTO
MONDAY NIGHT. HOWEVER WILL HAVE TO CONTINUE TO MONITOR TRENDS ON
THIS SYSTEM. FURTHER IN THE EXTENDED...FINALLY SOME DECENT SIGNS IN
THE LONG TERM ENSEMBLES THAT WE SEE TEMPERATURES WARMING TO AT OR
ABOVE NORMAL BY AROUND THE LAST WEEKEND OF THE MONTH. OF COURSE THIS
IS STILL FAR OUT...BUT MAYBE A SIGN THAT SPRING WILL FINALLY ARRIVE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1244 PM CDT WED APR 17 2013
STILL SEEING SOME VFR CONDITIONS NORTH OF I-90 AT THE START OF THE
PERIOD. HOWEVER...DETERIORATING CONDITIONS SPREADING NORTH ACROSS THE
AREA FROM NEBRASKA...WITH MVFR-IFR CEILINGS/VISIBILITY IN -DZ/BR
EXPECTED TO BE THE NORM THROUGHOUT THE AREA BY 21Z. IFR-LIFR CEILINGS
ALONG WITH IFR VISIBILITY THEN EXPECTED TO DOMINATE FOR THE REMAINDER
OF THE TAF PERIOD. PRECIPITATION TYPE WILL VARY FROM -DZ TO -SN...
DEPENDENT UPON MID LEVEL MOISTURE. CURRENT MODELS SHOWING -DZ MORE
LIKELY THROUGH THE EVENING...WITH -SN BECOMING MORE LIKELY AFTER
18/06Z. SNOW COULD BECOME MODERATE AT TIMES THROUGH CENTRAL PORTIONS
OF THE FORECAST AREA...INCLUDING AT KFSD...DURING THE LATTER HALF OF
THE TAF PERIOD...RESULTING IN MORE WIDESPREAD LIFR VISIBILITY WITH
PERIODS OF VLIFR VISIBILITY POSSIBLE. INCREASING NORTHERLY WINDS WILL
COMPOUND VISIBILITY ISSUES DURING THE LATTER HALF OF THE TAF PERIOD
AS WINDS GUSTING OVER 25KTS PRODUCE AREAS OF BLOWING SNOW ALONG WITH
THE FALLING SNOW.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 AM CDT
FRIDAY FOR SDZ038>040-052>056-058>071.
WINTER WEATHER ADVISORY UNTIL 1 AM CDT FRIDAY FOR SDZ050-057.
MN...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 AM CDT
FRIDAY FOR MNZ071-072-080-081-089-090-097-098.
IA...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 AM CDT
FRIDAY FOR IAZ001-002-012-020.
NE...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 AM CDT
FRIDAY FOR NEZ013.
&&
$$
UPDATE...MJF
SHORT TERM...08
LONG TERM...CHENARD
AVIATION...JH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1043 AM CDT WED APR 17 2013
.UPDATE...
ISSUED AT 1042 AM CDT WED APR 17 2013
MADE A BIT OF A MODIFICATION TO THE WINTER WEATHER ADVISORY IN
THAT WE POSTPONED THE START OF THE ADVISORY FOR MUCH OF OUR
WESTERN ZONES UNTIL 00Z THIS EVENING. WE DID KEEP IT AS IS FOR
GREGORY AND BRULE COUNTIES...PRIMARILY FOR THE THREAT OF LIGHT
FREEZING DRIZZLE. WINNER CONTINUES TO REPORT SOME SORT OF LIGHT
MIXED PRECIPITATION...AND TEMPERATURES SO FAR IN SOUTH CENTRAL SD
ARE BELOW FREEZING. THAT SAID...CHAMBERLAIN AND SURROUNDING
VICINITY MAY WARM UP TO JUST ABOVE FREEZING THIS AFTERNOON. BUT
SOME EXISTING SNOW COVER IN THOSE AREAS...THE ACTUAL GROUND
TEMPERATURE MAY BE A BIT COOLER ALLOWING ANY DRIZZLE TO PARTIALLY
FREEZE ON CONTACT.
OTHERWISE...THE WARM AIR ADVECTION WHICH HELPED TO CAUSE THE
PRECIPITATION THIS MORNING IN NORTHWEST IOWA IS EXITING AT THIS
TIME. THEREFORE A BULK OF OUR FORECAST AREA IS LEFT WITH MOISTURE
STARVED MID LEVELS...SEEN BEST ON THE RAP SOUNDINGS. THERE IS SNOW
TO THE WEST OF OUR FORECAST AREA WHERE 650MB FRONTOGENESIS IS
MAXIMIZED AND WHERE THERE IS MID LEVEL MOISTURE. HOWEVER IN OUR
FORECAST AREA...THE MAXIMIZED FRONTOGENESIS IS LOWER...AROUND
750MB TO 700MB...AND CONDITIONS ARE QUITE DRY IN THAT LAYER
THROUGH MUCH OF THE AFTERNOON. IN FACT IN OUR SOUTHEAST ZONES...
THE FRONTOGENESIS WAS IN THE LOWER LEVELS EARLIER TODAY...AND THAT
TOO IS TEMPORARILY WANING. SO THINKING OF LOWERING POPS IN MANY
AREAS UNTIL 21Z AND INCLUDE DRIZZLE...THEN BEGIN TO RAMP UP THE
POPS AGAIN LATE THIS AFTERNOON AS THE NEXT WELL ADVERTISED STRONG
WAVE APPROACHES.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CDT WED APR 17 2013
COMPLEX SET UP THIS MORNING WITH A COUPLE OF AREAS OF PRECIPITATION.
THE FIRST WAS A SNOW BAND THAT WAS VERY SLOWLY WORKING EAST INTO THE
FAR WESTERN CWA THIS MORNING. THE SOUTH AND EAST EDGE OF THIS BAND
HAS REALLY STRUGGLED TO DEVELOP BUT SOME HINTS THAT THERE WILL BE
SOME DEVELOPMENT THROUGH THE MORNING INTO THE WESTERN CWA. THE
SECOND AREA WAS ASSOCIATED WITH A POTENT AREA OF THETA E ADVECTION
AND MODERATE INSTABILITY ACROSS KANSAS. EXPECT THIS AREA TO
CONTINUE TO DEVELOP NORTHEAST THROUGH THE EARLY MORNING HOURS AND
CLIP THE SOUTHEAST THIRD OF THE CWA. WILL HAVE THUNDER OVER PARTS OF
NORTHWEST IOWA WITH DECENT ELEVATED INSTABILITY BUT NOT THINKING
SEVERE. INCREASED QPF AMOUNTS A BIT IN THESE AREAS AS WELL TO AROUND
A QUARTER TO THREE QUARTERS OF AN INCH THIS MORNING. IN BETWEEN
THESE TWO AREAS OVER EAST CENTRAL SOUTH DAKOTA AND SOUTHWEST
MINNESOTA THE POTENTIAL FOR NOT TOO MUCH ACTIVITY AS THE BAND OF
SNOW LOCKS UP TOT HE EAST TODAY AND THE CONVECTIVE ELEMENTS REMAIN
MAINLY SOUTH AND EAST. HOWEVER...ONCE THE UPPER LEVEL SUPPORT MOVES
INTO NEBRASKA TONIGHT EXPECT THIS RELATIVE BLANK SPOT TO FILL IN
QUICKLY THIS EVENING. SUSPECT MAINLY RAIN IN THE EASTERN CWA WHILE
THE WEST WILL BE MAINLY SNOW.
TONIGHT INTO THURSDAY POSES A PROBLEM FOR THE AREA WITH
FAIRLY GOOD AGREEMENT AMONGST THE VARIOUS MODELS DYNAMICALLY. THEY
ALL AGREE IN SWINGING THE STRONGEST PV ADVECTION NORTHWARD LATE
WEDNESDAY NIGHT INTO SOUTHEAST SOUTH DAKOTA THEN SHIFT IT EAST
GRADUALLY THROUGH THE DAY THURSDAY. IN FACT MEASURABLE SNOWFALL IS
PRETTY LIKELY IN THE EASTERN CWA THURSDAY EVENING. IT APPEARS THAT
THERE WILL BE A VERY STRONG MID LEVEL BOUNDARY IN PLACE WHICH WILL
COME NORTH THIS MORNING WITH THE STRONG LOW AND MID LEVEL THETA E
ADVECTION. THIS WAVE WILL BE ABLE TO INTERACT WITH THIS THERMAL
BOUNDARY AND IF THE SOUNDINGS ARE CORRECT SOMETHING CLOSE TO THE
750MB FRONT WILL YIELD THE MOST POTENT PRECIPITATION RATES AS A
PARCEL LIFTED FROM THIS LEVEL WOULD HAVE ABOUT 150 TO 300 J/KG
UNCAPPED CAPE TO WORK WITH. THERE MAY BE A SMALL RIBBON OF SLEET OR
FREEZING RAIN FROM ABOUT 22Z THROUGH 5Z BUT THIS LOOKS TO BE MORE OF
A TRANSITIONAL ISSUE VERSUS LAST WEEKS SUSTAINED PERIOD OF SLEET AND
FREEZING RAIN. SO FOR NOW NOT PLANNING ON ANY MAJOR ICE PROBLEMS AND
ONLY A BRIEF PERIOD FOR 1 TO 2 HOURS FROM ABOUT INTERSTATE 29 EAST
VERY LATE THIS AFTERNOON AND THIS EVENING. FAIRLY CONSISTENT SIGNALS
FROM THE MODELS THAT FROM ABOUT 0Z THURSDAY THROUGH 0Z FRIDAY A HALF
TO THREE QUARTERS OF AN INCH OF LIQUID WILL BE LIKELY AND MOST OF
THIS WILL FALL AS SNOW...AGAIN POSSIBLY A LITTLE SLEET TO START.
SUSPECT SNOWFALL RATIOS WILL BE LIMITED AND WILL AIM FOR AN AVERAGE
OF ABOUT 9:1 THROUGH THE EVENT...ALTHOUGH SOMETHING CLOSE TO 12:1
WILL BE POSSIBLE THURSDAY AFTERNOON. WILL ISSUE AN ADVISORY FOR
SOUTHWEST MINNESOTA INTO SOUTHEAST SOUTH DAKOTA FOR THE EXPECTED
SNOW TONIGHT INTO THURSDAY. BORDERLINE WARNING CRITERIA BUT WITH A
WET SNOW AND MELTING/COMPACTION POTENTIAL WILL LEAN TOWARDS A HIGH
END ADVISORY.
THE SNOW SHOULD WIND DOWN THURSDAY NIGHT WITH FRIDAY JUST LOOKING
WINDY AND COLD. TEMPERATURES FROM TODAY INTO FRIDAY SHOULD BE ABOUT
20 TO 25 DEGREES BELOW NORMAL.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 329 AM CDT WED APR 17 2013
THIS WEEKEND INTO EARLY NEXT WEEK SHOULD SEE CONTINUED BELOW NORMAL
TEMPERATURES WITH TROUGHING REMAINING OVER THE CENTRAL US. WAVE
MOVING THROUGH SATURDAY NIGHT INTO SUNDAY SHOULD BRING AT LEAST
SCATTERED SHOWERS TO THE AREA...THERMAL PROFILES LOOK WARM ENOUGH FOR
ANY PRECIP TO BE RAIN WITH THIS WAVE. HIGHS SATURDAY SHOULD MAINLY
BE IN THE 40S...COULD SEE SOME 50S ON SUNDAY AHEAD OF THE
APPROACHING COLD FRONT. THE FRONT PUSHES THROUGH SUNDAY NIGHT INTO
MONDAY RESULTING IN HIGHS BACK INTO THE 40S FOR EARLY NEXT WEEK.
RAIN SHOWER CHANCES CONTINUE SUNDAY NIGHT INTO MONDAY WITH THIS
FRONTAL PASSAGE AND DIGGING WAVE. THERMAL PROFILES SUGGEST BY LATER
MONDAY ANYTHING THAT FALLS COULD BE SNOW. HOWEVER MODELS DIFFER ON
THEIR HANDLING OF THE DIGGING WAVE...WITH THE LATEST 0Z ECMWF THE
MOST AGGRESSIVE WITH THE SYSTEM...CUTTING THE LOW OFF TO OUR SOUTH AND
GIVING PORTIONS OF OUR CWA SNOW OR RAIN ON TUESDAY. THIS IS AN
OUTLIER SOLUTION AT THIS TIME...WITH THE MORE LIKELY RESULT BEING A
MORE PROGRESSIVE WAVE AND JUST LIGHTER QPF AMOUNTS SUNDAY NIGHT INTO
MONDAY NIGHT. HOWEVER WILL HAVE TO CONTINUE TO MONITOR TRENDS ON
THIS SYSTEM. FURTHER IN THE EXTENDED...FINALLY SOME DECENT SIGNS IN
THE LONG TERM ENSEMBLES THAT WE SEE TEMPERATURES WARMING TO AT OR
ABOVE NORMAL BY AROUND THE LAST WEEKEND OF THE MONTH. OF COURSE THIS
IS STILL FAR OUT...BUT MAYBE A SIGN THAT SPRING WILL FINALLY ARRIVE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 645 AM CDT WED APR 17 2013
COMPLEX WEATHER SYSTEM WILL IMPACT THE AREA THROUGH THE TAF PERIOD.
CURRENTLY SEEING AN AREA OF MODERATE RAIN AND EMBEDDED THUNDER MOVING
ACROSS NORTHWEST IOWA. THIS AREA SHOULD EXIT TO THE EAST BY MID
MORNING. OTHERWISE THE TREND IS FOR LIGHTER PRECIPITATION TODAY WITH
SLIGHTLY HIGHER CIGS AND VIS THAN PREVIOUSLY THOUGHT. THINK AREA OF
LIGHT PRECIPITATION WILL DEVELOP LATER THIS MORNING ACROSS THE AREA.
THIS WILL BE MAINLY SNOW AT KHON...ALTHOUGH VISIBILITIES SHOULD NOT
BE IMPACTED TOO MUCH. CLOSER TO KFSD...LOOKING AT A LIGHT WINTRY
MIX...AND MAINLY RAIN AT KSUX THROUGH THE DAY. SLOWLY LOWERED CIGS
THROUGH THE DAY...WITH MVFR BECOMING DOMINANT BY AFTERNOON. ANOTHER
HEAVIER BATCH OF PRECIPITATION SHOULD FORM OVER NEBRASKA AND MOVE
INTO OUR AREA TONIGHT INTO THURSDAY. THIS SHOULD BE MAINLY SNOW AT
KFSD AND KHON...WITH LOWERING CIGS AND VIS LIKELY INTO THE IFR AND
POSSIBLY LIFR RANGE AT TIMES. KSUX SHOULD SEE THIS BEGIN AS RAIN AND
TRANSITION TO SNOW BY 12Z. NORTHERLY WINDS WILL ALSO PICK UP BY LATER
TONIGHT...GUSTING INTO THE 20 TO 30 KT RANGE.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 AM CDT
FRIDAY FOR SDZ038>040-052>056-058>071.
WINTER WEATHER ADVISORY UNTIL 1 AM CDT FRIDAY FOR SDZ050-057.
MN...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 AM CDT
FRIDAY FOR MNZ071-072-080-081-089-090-097-098.
IA...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 AM CDT
FRIDAY FOR IAZ001-002-012-020.
NE...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 AM CDT
FRIDAY FOR NEZ013.
&&
$$
UPDATE...MJF
SHORT TERM...08
LONG TERM...CHENARD
AVIATION...CHENARD
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1017 PM MDT TUE APR 16 2013
.UPDATE...
ISSUED AT 802 PM MDT TUE APR 16 2013
02Z SURFACE ANALYSIS HAD LOW PRESSURE OVER SOUTH CENTRAL CO WITH
INVERTED TROUGH INTO SOUTHEAST MT. 00Z UPPER AIR ANALYSIS HAD
110KT JET STREAK FROM NORTH CENTRAL CO INTO NORTHWEST SD WITH THE
RIGHT ENTRANCE REGION OF JET RESPONSIBLE FOR BURST OF SN NOW SHIFTING
EAST OF THE BLACK HILLS INTO CENTRAL PORTIONS OF SD. 2-4 INCHES
FELL SOUTHWEST SD...SEE LOCAL STORM REPORTS. RATHER STRONG
850-700MB FRONTOGENESIS NOTED BELOW JET. 00Z RAP DEPICTED FIRST
AREA OF PRECIPITATION DECENTLY...SHIFTING TO THE NORTH AND EAST
THIS EVENING. NEXT IMPULSE APPEARS TO BE OVER SOUTHWEST UT IN LEFT
EXIT REGION OF 100KT JET STREAK PER WATER VAPOUR. THERE MIGHT EVEN
BE AN IMPULSE OVER NORTH CENTRAL CO. ACTIVITY WILL MOVE NORTHEAST
OVERNIGHT BRINGING ANOTHER BURST OR TWO OF MODERATE/HEAVY
SNOW...ESPECIALLY ACROSS SOUTHWEST PORTIONS OF CWA. LATEST
GUIDANCE SUGGESTS 3-6 INCHES ACCUMULATION OVERNIGHT...AND THAT IS
PRETTY CLOSE TO CURRENT FORECAST. WILL LEAVE CURRENT HEADLINES AND
GIST OF FORECAST INTACT...BUT WILL CONTINUE TO WATCH ANY SHIFTS OF
MAIN PRECIPITATION BAND THROUGH THE NIGHT.
&&
.SHORT TERM...THIS EVENING THROUGH WEDNESDAY NIGHT
ISSUED AT 228 PM MDT TUE APR 16 2013
CURRENT SURFACE ANALYSIS PLACES LOW OVER SOUTHWESTERLY COLORADO
WITH HIGH OVER THE MIDWEST. UPPER LEVEL ANALYSIS PLACES DEEP TROF
OVER THE WESTERN CONUS STRETCHING FROM THE NORTHERN ROCKIES INTO
THE GREAT BASIN. INITIAL WAVES EJECTING AHEAD TO THE TROF THRU
SWRLY FLOW INTO OUR AREA CONTINUE TO BRING BROAD AREA OF SNOW OVER
MUCH OF THE CWA. ACCUMULATIONS HAVE BEEN REPORTED OVER THE SWRN
CWA...THOUGH OVER THE SODAK PLAINS SNOW CONTINUES TO MELT ON
ROADWAYS.
FOR TONIGHT...TROF CONTINUES TO DEEPEN AND STARTS TO SLOWLY SHIFT
TO THE EAST. AS IT DOES...BROAD SCALE LIFT DEVELOPS OVER THE AREA
BRINGING INCREASING SNOWFALL RATES. WITH THIS ALONG WITH LACK OF
INSOLATION...EXPECT SNOW TO START ACCUMULATING OVER REMAINING PTNS
OF THE SODAK PLAINS LATE THIS AFT INTO EARLY THIS EVE. SOME
UPSLOPE ENHANCEMENT MAY DEVELOP OVER THE ERN FOOTHILLS WITH
EASTERLY COMPONENT TO LOW LEVEL FLOW POSSIBLY RESULTING IN SOME
LOCALLY HIGHER AMOUNTS.
ON WEDNESDAY...UPPER TROF CONTINUES TO WORK ITS WAY EAST WITH AXIS
STRETCHING FROM SRN SASKATCHEWAN TOWARDS THE FOUR CORNERS REGION BY
LATE AFTERNOON. BROAD SCALE LIFT CONTINUES THROUGH MOST OF THE DAY
WITH SNOW CONTINUING. SFC LOW PUSHES FROM COLORADO INTO THE PLAINS
WITH PRESSURE GRADIENT TIGHTEN SOME OVER OUR AREA BRINGING BREEZY
CONDITIONS ALONG WITH SOME BLOWING/DRIFTING SNOW. BY LATE
AFTERNOON INTO THE EVENING...TROF AXIS WILL SLOWLY WORK ITS WAY
EAST INTO THE CWA WITH RIDGING QUICKLY DEVELOPING IN ITS WAKE.
SNOW WILL THEN SLOWLY START DIMINISHING FROM WEST TO EAST...LINGERING
OVER SOUTH CENTRAL SD INTO THE MORNING.
&&
.LONG TERM...THURSDAY THROUGH TUESDAY
ISSUED AT 228 PM MDT TUE APR 16 2013
WINTER STORM WILL EXIT THE REGION WEST TO EAST ON THURSDAY WITH
LINGERING SNOW POSSIBLE ACROSS SOUTH CENTRAL SD THROUGH THURSDAY
AFTERNOON. DRY CONDITIONS ARE EXPECTED THURSDAY NIGHT AND FRIDAY AS
A SHORT WAVE RIDGE CROSSES THE NORTHERN PLAINS. A FEW NORTHERN
STREAM WAVES WILL CROSS THE REGION FRIDAY NIGHT THROUGH
MONDAY...BRINGING ADDITIONAL CHANCES FOR LIGHT PRECIPITATION.
TEMPERATURES WILL REMAIN WELL BELOW AVERAGE THROUGH THE EXTENDED
PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1015 PM MDT TUE APR 16 2013
WIDESPREAD IFR/LIFR CONDITIONS DUE TO SN WILL CONTINUE THROUGH
WEDNESDAY AFTERNOON ACROSS MUCH OF THE. CONDITIONS WILL SLOWLY
IMPROVE WEDNESDAY EVENING AS HEAVIEST SNOWS PUSHES EAST.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER STORM WARNING UNTIL MIDNIGHT MDT WEDNESDAY NIGHT FOR
SDZ024>032-041-042-072>074.
WINTER STORM WARNING UNTIL 6 AM MDT /7 AM CDT/ THURSDAY FOR
SDZ043-044-046-047-049.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT WEDNESDAY NIGHT FOR
SDZ012>014.
WY...WINTER STORM WARNING UNTIL MIDNIGHT MDT WEDNESDAY NIGHT FOR
WYZ054>058.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT WEDNESDAY NIGHT FOR
WYZ071.
&&
$$
UPDATE...HELGESON
SHORT TERM...77
LONG TERM...15
AVIATION...HELGESON
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
426 PM CDT WED APR 17 2013
.MESOSCALE UPDATE...SEVERE THUNDERSTORM WATCH CONTINUES UNTIL 9 PM.
ONGOING CONVECTION OVER EASTERN COUNTIES BEING MONITORED FOR
POSSIBLE INTENSIFICATION AT THIS TIME OF MAX HEATING, AND
SATELLITE PICS SHOW GUST FRONT MOVING WESTWARD TOWARD THE I-65
CORRIDOR IS ASSOCIATED WITH A BAND OF MODERATE CU. DOPPLER
INDICATES GUSTS OF 25 TO 30 MPH WILL OCCUR WITH THE PASSAGE OF THE
GUST FRONT FRONT AND ASSOCIATED BAND OF CU WILL ALSO HAVE TO BE
MONITORED FOR THUNDERSTORM DEVELOPMENT AS IT PUSHES THROUGH AN
UNSTABLE AIR MASS (WHERE RUC SOUNDINGS SHOW LI`S AROUND -6 AND
CAPES OF 2500 J/KG).
ONE CAVEAT IS THAT LATEST RUC SHOWS UPPER LEVEL SUBSIDENCE MAY BE
WORKING AGAINST DEVELOPMENT OVER WESTERN PARTS OF THE WATCH AREA
THIS AFTERNOON. HOWEVER, STILL CAN`T RULE OUT SOME ISOLATED
CONVECTION POPPING UP IN THE AFTERNOON HEAT.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
19
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1257 PM CDT WED APR 17 2013
.AVIATION...
BREEZY SW WINDS AT KLBB WILL CONTINUE THROUGH EARLY EVENING WITH SOME
MINOR VSBY RESTRICTIONS DUE TO BLDU. A COLD FRONT WILL MOVE
THROUGH OVERNIGHT WITH BRISK NORTH WINDS CONTINUING THROUGH
THURSDAY MORNING. AT KCDS...LOW CEILINGS MAY BREAK OUT FOR A
PERIOD IN THE AFTERNOON BUT CONFIDENCE IS LOW. THERE IS ALSO
UNCERTAINTY IN THE WIND DIRECTION AND THUNDERSTORM ACTIVITY IS EXPECTED
IN THE VICINITY. THE COLD FRONT WILL MOVE THOUGH AROUND 05-06Z AND
SKY CONDITIONS SHOULD IMPROVE THURSDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 1145 AM CDT WED APR 17 2013/
UPDATE...
THE CONVECTIVE FORECAST FOR THIS AFTERNOON AND EVENING IS TRICKY AS
IT HINGES ON THE COMPLEX INTERPLAY OF STRONG DYNAMICS ALOFT AND
SEVERAL MORE MESOSCALE-TYPE FEATURES AT THE SURFACE. AT 11 AM...A
SURFACE LOW WAS DEEPENING ACROSS ERN NM WITH A DRYLINE FORMING UP
ALONG THE NM/TX STATE LINE. FARTHER EAST...COOL...AND MOIST AIR
REMAINED BANKED UP AGAINST THE CAPROCK WITH A WARM FRONT NOSING
NORTHWARD INTO STONEWALL COUNTY. THIS IS CREATING QUITE A WIDE
RANGE OF SENSIBLE WX CONDITIONS ACROSS THE AREA LATE THIS MORNING.
MUCH OF THE MORNING MODEL GUIDANCE DO NOT HANDLE THE POSITION OF
THE SURFACE FEATURES WELL WHICH LOWERS CONFIDENCE IN THEIR
AFTERNOON PROJECTIONS.
THE GENERAL TREND OF THE FORECAST REMAINS INTACT THOUGH AS THE
DRYLINE SHOULD MIX ACROSS MOST OF THE CAPROCK. HOWEVER...THE
DRYLINE WILL ENCOUNTER MORE RESISTANCE ACROSS THE NORTH...NAMELY
SWISHER...BRISCOE AND FLOYD COUNTIES WHERE COOL UPSLOPE FLOW IS
PERSISTENT. THE 15Z RAP NEVER ERODES THIS COOL WEDGE AND INSTEAD
IT SERVES AS A BOUNDARY TO INITIATE CONVECTION AROUND 20 UTC.
OTHER GUIDANCE STILL TAKES THE DRYLINE FARTHER EAST...ALTHOUGH
PERHAPS NOT QUITE AS FAR AS PREVIOUSLY INDICATED. ANOTHER CONCERN
IS TEMPERATURES AND PROGRESS OF THE WARM SECTOR. WHILE THERE
SHOULD BE PLENTY OF CONDITIONAL INSTABILITY /SBCAPES IN EXCESS OF
2000 J/KG ACROSS THE ROLLING PLAINS...IT IS POSSIBLE THAT CLOUD
COVER AND COOLER TEMPS MAY HELP KEEP OUR NE ZONES CAPPED. WHILE IT
APPEARS THAT THE MOST LIKELY SCENARIO IS THAT T-STORM DEVELOPMENT WILL
BE FAVORED FROM ERN PORTIONS OF COTTLE AND KING COUNTIES NEWD TO
THE RED RIVER VALLEY WHERE THE DRYLINE/FRONT TRIPLE POINT IS
EXPECTED TO BE LOCATED...WE HAVE GONE AHEAD AND PULLED POPS BACK
WEST ACROSS THE FAR SRN PANHANDLE AND NRN ROLLING PLAINS IN CASE
1. THE DRYLINE HANGS UP FARTHER WEST IN THAT AREA...AND 2. THE CAP
CAN BREAK DESPITE THE COOLER TEMPS. CAPE AND SHEAR SHOULD BE MORE
THAN ADEQUATE FOR SUPERCELLS AND A THREAT OF HAIL/DAMAGING WINDS
AND ISOLATED TORNADOES...ESPECIALLY ALONG THE REMNANT FRONTAL
BOUNDARY...WHICH COULD BE PRESENT IN THE ERN ROLLING PLAINS.
PREV DISCUSSION... /ISSUED 658 AM CDT WED APR 17 2013/
AVIATION...
WE ARE STARTING OUT WITH AN LIFR CIG AND VSBY AT KCDS AND UNSETTLED
IFR TO MVFR CONDITIONS AT KLBB. TIMING THE IMPROVEMENT OF THESE
CONDITIONS WILL BE TRICKY...THOUGH KLBB WILL CERTAINLY IMPROVE
RAPIDLY BY MID MORNING OR SO...PERHAPS AN HOUR EARLIER OR LATER
THAN STATED IN THE TAF. VSBY AT KLBB LIKELY TO DETERIORATE HOWEVER
BY LATER IN THE AFTERNOON AS STRONG SOUTHWEST WINDS SHOULD BE ABLE
TO KICK BLOWING DUST INTO THE AIR WITH POSSIBLE MVFR VSBY ONCE
AGAIN. THERE IS GREATER UNCERTAINTY IN TIMING IMPROVEMENT AT KCDS
AS SOME SOLUTIONS INDICATE VERY LITTLE TO NO IMPROVEMENT WHILE
OTHERS INDICATE LOW CLOUDS COMPLETELY CLEARING OUT BY MID
AFTERNOON. WE HAVE KCDS PLAYED IN-BETWEEN THESE TWO CAMPS. A
STRONG COLD FRONT WILL ARRIVE DURING THE EVENING...EARLY AT KCDS
AND NEARER MIDNIGHT OR 06Z AT KLBB. THIS FRONT MAY PROVE A FOCUS
FOR SEVERE WEATHER MAINLY NEAR OR JUST EAST OF KCDS LATER TODAY SO
AVIATION USING THAT TERMINAL SHOULD PAY CONSIDERABLE ATTENTION TO
TAF UPDATES AND RADAR TRENDS. AN MVFR LAYER SEEMS MOST LIKELY AT
KCDS AGAIN TOWARDS THE END OF THIS FORECAST FOLLOWING THE
FRONT...AND LIKELY WILL OCCUR JUST BEYOND THIS FORECAST AT KLBB AS
WELL. RMCQUEEN
PREV DISCUSSION... /ISSUED 447 AM CDT WED APR 17 2013/
SHORT TERM...
LOW LEVEL MOISTURE WAS EDGING BACK WEST VIA ANOTHER WEAKENING AND
SHALLOW FRONTAL SLOSH THROUGH NORTHERN AND EASTERN ZONES AND
SOUTHEAST COMPONENT RETURNING MOISTURE ONTO THE CAPROCK. LIFT WAS
OCCURRING ALONG THE WESTERN BORDER WITH A WAVE LIFTING NORTHEAST
ACROSS THE AREA...BUT ONLY RESULTING IN MARGINAL ENHANCEMENT OF MID
AND HIGH CLOUDS. THUNDER WAS DEVELOPING MUCH FURTHER UPSTREAM OVER
THE CENTRAL PLAINS FROM THIS WAVE AS OUR AIRMASS REMAINED
CONSTRAINED BY A SOLID CAP NEAR THE 800 MB LEVEL. LOW CLOUDS SHOULD
EVENTUALLY EXPAND OVER MOST OF THE CENTRAL AND EASTERN AREAS BY
EARLY WEDNESDAY AND ALONG WITH LIGHT SHOWER OR DRIZZLE CHANCES
SHOULD BE THE DOMINANT WEATHER FOR THE MORNING. WE ALSO WILL SEE THE
LOW CLOUDS ERODE QUICKLY BY MID TO LATE MORNING ON THE CAPROCK WITH
DEEPER MIXING INTO THE STRONGER SOUTHWEST COMPONENTS ALOFT.
BY AFTERNOON THE DRY GUSTY SOUTHWEST WINDS SHOULD BE THE PRIMARY
WEATHER WITH MOISTURE CONTINUING TO ERODE SLOWLY THROUGH PARTS OF
THE ROLLING PLAINS AS WELL. CONSIDERABLE DISAGREEMENT REMAINS
BETWEEN MODEL CAMPS HOWEVER REGARDING NORTHWARD AND WESTWARD EXTENT
OF MIXED AIRMASS THROUGH THE ROLLING PLAINS. WE TEND TO LEAN TOWARDS
A MORE BACKED LOW LEVEL COMPONENT YET ARE NOT CONVINCED THAT AT
LEAST SOME PERIOD OF DEEP MIXING COULD ALSO WORK AS FAR NORTH AND
EAST AS CHILDRESS. A CONDITIONAL MENTION OF THUNDER AND SEVERE
STORMS WILL DEVELOP FROM THE FRONT AND DRY-LINE INTERSECTION
SOUTHWARD THROUGH EASTERN PORTIONS OF THE ROLLING PLAINS
ESPECIALLY...WHICH IS CONSISTENT WITH PREVIOUS FORECAST.
THUNDER CHANCES SHOULD INCREASE WITH ARRIVAL OF A STRONGER COLD
FRONT THIS EVENING THAT COULD FINALLY ALLOW CONVECTION TO DEEPEN AND
REALIZE THE CONSIDERABLE BUOYANT AND SHEARED ENVIRONMENT. THE SLOWLY
ERODING AND LIFTING CAP MAY STILL OFFER SOME RESISTANCE...HOWEVER...
THUS LIMITING CONFIDENCE FURTHER SOUTH THROUGH THE ROLLING PLAINS.
COLD FRONT WILL SURGE SOUTHWARD OVERNIGHT SPREADING LOW CLOUDS ONCE
MORE ACROSS MUCH OF THE AREA. WINDS MAY BECOME CLOSE TO WIND
ADVISORY LEVELS. PRECIPITATION CHANCES BEHIND THE FRONT APPEAR
SMALL...THOUGH WE RETAINED MINIMAL DRIZZLE MENTION NORTHERN ZONES
INCLUDING FREEZING DRIZZLE WITH TEMPERATURES EXPECTED TO DROP A
LITTLE BELOW FREEZING LATER TONIGHT ACROSS THE SOUTHWEST PANHANDLE
COUNTIES. RMCQUEEN
LONG TERM...
THURSDAY MORNING WILL START OFF BRISK ACROSS THE FAR SOUTHERN TEXAS
PANHANDLE...SOUTH PLAINS...AND ROLLING PLAINS BEHIND A STRONG COLD
FRONT EXHIBITING ABRUPT PRESSURE RISES. DO NOT BELIEVE WIND ADVISORY
CRITERIA WILL BE MET FOR AN EXTENDED PERIOD GIVEN AN OVERNIGHT
FRONTAL PASSAGE AND H70 200 NAUTICAL MILE HEIGHT GRADIENTS
SUPPORTING WINDS TOPPING OUT NEAR THE LOW END THRESHOLD OF 30 MPH.
SKIES SHOULD QUICKLY CLEAR AS DRIER AIR FILTERS IN ALONG WITH STOUT
COLD AIR ADVECTION ONLY ALLOWING HIGH TEMPERATURES TO REACH THE
UPPER 40S NORTHWEST TO MID-UPPER 50S SOUTHEAST. WINDS WILL DECREASE
THROUGH THE AFTERNOON AS JET MAX ALOFT PUSHES EAST AND PRESSURE
GRADIENT WEAKENS AHEAD OF APPROACHING SURFACE RIDGE FROM THE
ROCKIES. WHILE PORTIONS OF THE CAPROCK NORTH AND WEST OF LUBBOCK MAY
SEE FREEZING TEMPERATURES THURSDAY MORNING...A WIDESPREAD AND MUCH
HARDER FREEZE WILL TAKE PLACE FRIDAY MORNING AS CLEAR SKIES...LIGHT
WINDS...AND DRY CONDITIONS PROMOTE STRONG RADIATIONAL COOLING WITH
SURFACE RIDGING EXTENDING ACROSS THE AREA. NORTHWEST ZONES WILL
LIKELY BOTTOM OUT IN THE MID 20S WHILE UPPER 20S TO LOW 30S OCCUR
ELSEWHERE. FORECASTING LUBBOCK AND CHILDRESS TO BOTH BREAK THEIR
RECORD LOWS OF 31 AND 35 RESPECTIVELY. WILL CONTINUE TO MONITOR
TRENDS FOR FREEZE WATCH ISSUANCE AND HOLD OFF FOR NOW TO ALLOW THE
WEATHER SCENARIO FOR TODAY/TONIGHT DISCUSSED IN THE SHORT TERM TO
PLAY OUT.
NORTHWEST FLOW AND RISING HEIGHTS WILL TAKE PLACE ALOFT IN WAKE OF
THE EXITING UPPER TROUGH AND GENERATE LEE TROUGHING ACROSS SOUTHEAST
COLORADO AND NORTHEAST NEW MEXICO FRIDAY...BACKING WINDS
SOUTH/SOUTHWESTERLY AND SUBSEQUENTLY WARMING TEMPERATURES BACK INTO
THE 60S WITH OVERNIGHT LOWS FRIDAY INTO SATURDAY REMAINING ABOVE THE
FREEZING MARK. WARMING LOOKS TO CONTINUE INTO THE WEEKEND BEFORE A
SUBTLE SHORTWAVE TROUGH BACKS THE UPPER FLOW AND SENDS A WEAK COOL
FRONT/WIND SHIFT TOWARD THE REGION...POSSIBLY STALLING BEFORE
CLEARING THE ROLLING PLAINS. THUS...DO NOT EXPECT HIGHS TO TAKE MUCH
OF A HIT FROM SATURDAY/S IN THE MID TO UPPER 70S.
MONDAY IS SETTING UP TO BE ANOTHER SEASONABLE DAY IN THE MID TO
UPPER 70S AS SOUTHERLY WINDS DRAW IN WARM AIR AHEAD OF A SURFACE LOW
NEAR THE TEXAS PANHANDLE. AN UPPER TROUGH DIGGING OUT OF THE
INTERMOUNTAIN WEST WILL BE APPROACHING ALOFT AND PROVIDING SOME
LARGE SCALE FORCING FOR ASCENT. WILL HAVE TO SEE HOW MOISTURE RETURN
PLAYS OUT AS TO WHETHER STORMS WILL BE POSSIBLE...MOST LIKELY IN THE
FAR SOUTHEAST PANHANDLE AND ROLLING PLAINS. WILL KEEP THE FORECAST
DRY AT THIS POINT GIVEN NWP INCONSISTENCIES IN THE INTENSITY OF THE
TROUGH AND ASSOCIATED COLD FRONT. NONETHELESS...TUESDAY LOOKS COOLER
ONCE AGAIN BEFORE TEMPERATURES REBOUND INTO MID-LATE WEEK AS HEIGHTS
INCREASE ALOFT.
FIRE WEATHER...
THERE APPEARS TO BE LITTLE DISAGREEMENT THAT STRONG SOUTHWEST WINDS
WILL DEVELOP FOR MOST IF NOT ALL LOCATIONS ON THE CAP-ROCK THIS
AFTERNOON LASTING INTO THE EARLY EVENING. THE PERIOD WITH STRONGEST
WINDS SHOULD BE LATE IN THE AFTERNOON PERHAPS INTO THE EARLY
EVENING. THERE REMAINS UNCERTAINTY...HOWEVER...ABOUT POTENTIAL FOR
THE STRONG DRY WINDS TO SCOUR OUT THE MOISTURE OVER THE ROLLING
PLAINS. WE FAVOR A BLEND THAT RETAINS A SOMEWHAT BACKED LOW LEVEL
FLOW ACROSS THE ROLLING PLAINS...ESPECIALLY THE FAR EASTERN ROW OF
COUNTIES THROUGH THE AFTERNOON. THIS STILL MAY ALLOW ELEVATED AND
EVEN BRIEFLY CRITICAL FIRE WEATHER CONDITIONS TO DEVELOP FROM
BRISCOE AND HALL COUNTIES SOUTHWARD THROUGH KENT COUNTY. FUEL LOADS
REMAIN MINIMAL BUT THE ENERGY RELEASE COMPONENTS HAVE BECOME MORE
ELEVATED. SO...WE WILL ISSUE A RED FLAG WARNING FOR AREAS ON THE
CAPROCK WITH A FIRE DANGER STATEMENT FOR PORTIONS OF THE ROLLING
PLAINS AS WELL. RMCQUEEN
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 30 48 24 60 35 / 10 0 0 0 0
TULIA 31 49 25 61 36 / 10 0 0 0 0
PLAINVIEW 34 51 26 61 38 / 10 0 0 0 0
LEVELLAND 34 54 28 63 37 / 0 0 0 0 0
LUBBOCK 37 54 29 62 40 / 0 0 0 0 0
DENVER CITY 39 55 29 62 39 / 0 0 0 0 0
BROWNFIELD 39 55 30 62 38 / 0 0 0 0 0
CHILDRESS 37 53 30 64 41 / 40 0 0 0 0
SPUR 41 55 30 64 38 / 20 0 0 0 0
ASPERMONT 47 57 31 65 40 / 40 0 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: TXZ021>023-027>030-033>036-039>042.
&&
$$
33
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
1145 AM CDT WED APR 17 2013
.UPDATE...
THE CONVECTIVE FORECAST FOR THIS AFTERNOON AND EVENING IS TRICKY AS
IT HINGES ON THE COMPLEX INTERPLAY OF STRONG DYNAMICS ALOFT AND
SEVERAL MORE MESOSCALE-TYPE FEATURES AT THE SURFACE. AT 11 AM...A
SURFACE LOW WAS DEEPENING ACROSS ERN NM WITH A DRYLINE FORMING UP
ALONG THE NM/TX STATE LINE. FARTHER EAST...COOL...AND MOIST AIR
REMAINED BANKED UP AGAINST THE CAPROCK WITH A WARM FRONT NOSING
NORTHWARD INTO STONEWALL COUNTY. THIS IS CREATING QUITE A WIDE
RANGE OF SENSIBLE WX CONDITIONS ACROSS THE AREA LATE THIS MORNING.
MUCH OF THE MORNING MODEL GUIDANCE DO NOT HANDLE THE POSITION OF
THE SURFACE FEATURES WELL WHICH LOWERS CONFIDENCE IN THEIR
AFTERNOON PROJECTIONS.
THE GENERAL TREND OF THE FORECAST REMAINS INTACT THOUGH AS THE
DRYLINE SHOULD MIX ACROSS MOST OF THE CAPROCK. HOWEVER...THE
DRYLINE WILL ENCOUNTER MORE RESISTANCE ACROSS THE NORTH...NAMELY
SWISHER...BRISCOE AND FLOYD COUNTIES WHERE COOL UPSLOPE FLOW IS
PERSISTENT. THE 15Z RAP NEVER ERODES THIS COOL WEDGE AND INSTEAD
IT SERVES AS A BOUNDARY TO INITIATE CONVECTION AROUND 20 UTC.
OTHER GUIDANCE STILL TAKES THE DRYLINE FARTHER EAST...ALTHOUGH
PERHAPS NOT QUITE AS FAR AS PREVIOUSLY INDICATED. ANOTHER CONCERN
IS TEMPERATURES AND PROGRESS OF THE WARM SECTOR. WHILE THERE
SHOULD BE PLENTY OF CONDITIONAL INSTABILITY /SBCAPES IN EXCESS OF
2000 J/KG ACROSS THE ROLLING PLAINS...IT IS POSSIBLE THAT CLOUD
COVER AND COOLER TEMPS MAY HELP KEEP OUR NE ZONES CAPPED. WHILE IT
APPEARS THAT THE MOST LIKELY SCENARIO IS THAT T-STORM DEVELOPMENT WILL
BE FAVORED FROM ERN PORTIONS OF COTTLE AND KING COUNTIES NEWD TO
THE RED RIVER VALLEY WHERE THE DRYLINE/FRONT TRIPLE POINT IS
EXPECTED TO BE LOCATED...WE HAVE GONE AHEAD AND PULLED POPS BACK
WEST ACROSS THE FAR SRN PANHANDLE AND NRN ROLLING PLAINS IN CASE
1. THE DRYLINE HANGS UP FARTHER WEST IN THAT AREA...AND 2. THE CAP
CAN BREAK DESPITE THE COOLER TEMPS. CAPE AND SHEAR SHOULD BE MORE
THAN ADEQUATE FOR SUPERCELLS AND A THREAT OF HAIL/DAMAGING WINDS
AND ISOLATED TORNADOES...ESPECIALLY ALONG THE REMNANT FRONTAL
BOUNDARY...WHICH COULD BE PRESENT IN THE ERN ROLLING PLAINS.
&&
.PREV DISCUSSION... /ISSUED 658 AM CDT WED APR 17 2013/
AVIATION...
WE ARE STARTING OUT WITH AN LIFR CIG AND VSBY AT KCDS AND UNSETTLED
IFR TO MVFR CONDITIONS AT KLBB. TIMING THE IMPROVEMENT OF THESE
CONDITIONS WILL BE TRICKY...THOUGH KLBB WILL CERTAINLY IMPROVE
RAPIDLY BY MID MORNING OR SO...PERHAPS AN HOUR EARLIER OR LATER
THAN STATED IN THE TAF. VSBY AT KLBB LIKELY TO DETERIORATE HOWEVER
BY LATER IN THE AFTERNOON AS STRONG SOUTHWEST WINDS SHOULD BE ABLE
TO KICK BLOWING DUST INTO THE AIR WITH POSSIBLE MVFR VSBY ONCE
AGAIN. THERE IS GREATER UNCERTAINTY IN TIMING IMPROVEMENT AT KCDS
AS SOME SOLUTIONS INDICATE VERY LITTLE TO NO IMPROVEMENT WHILE
OTHERS INDICATE LOW CLOUDS COMPLETELY CLEARING OUT BY MID
AFTERNOON. WE HAVE KCDS PLAYED IN-BETWEEN THESE TWO CAMPS. A
STRONG COLD FRONT WILL ARRIVE DURING THE EVENING...EARLY AT KCDS
AND NEARER MIDNIGHT OR 06Z AT KLBB. THIS FRONT MAY PROVE A FOCUS
FOR SEVERE WEATHER MAINLY NEAR OR JUST EAST OF KCDS LATER TODAY SO
AVIATION USING THAT TERMINAL SHOULD PAY CONSIDERABLE ATTENTION TO
TAF UPDATES AND RADAR TRENDS. AN MVFR LAYER SEEMS MOST LIKELY AT
KCDS AGAIN TOWARDS THE END OF THIS FORECAST FOLLOWING THE
FRONT...AND LIKELY WILL OCCUR JUST BEYOND THIS FORECAST AT KLBB AS
WELL. RMCQUEEN
PREV DISCUSSION... /ISSUED 447 AM CDT WED APR 17 2013/
SHORT TERM...
LOW LEVEL MOISTURE WAS EDGING BACK WEST VIA ANOTHER WEAKENING AND
SHALLOW FRONTAL SLOSH THROUGH NORTHERN AND EASTERN ZONES AND
SOUTHEAST COMPONENT RETURNING MOISTURE ONTO THE CAPROCK. LIFT WAS
OCCURRING ALONG THE WESTERN BORDER WITH A WAVE LIFTING NORTHEAST
ACROSS THE AREA...BUT ONLY RESULTING IN MARGINAL ENHANCEMENT OF MID
AND HIGH CLOUDS. THUNDER WAS DEVELOPING MUCH FURTHER UPSTREAM OVER
THE CENTRAL PLAINS FROM THIS WAVE AS OUR AIRMASS REMAINED
CONSTRAINED BY A SOLID CAP NEAR THE 800 MB LEVEL. LOW CLOUDS SHOULD
EVENTUALLY EXPAND OVER MOST OF THE CENTRAL AND EASTERN AREAS BY
EARLY WEDNESDAY AND ALONG WITH LIGHT SHOWER OR DRIZZLE CHANCES
SHOULD BE THE DOMINANT WEATHER FOR THE MORNING. WE ALSO WILL SEE THE
LOW CLOUDS ERODE QUICKLY BY MID TO LATE MORNING ON THE CAPROCK WITH
DEEPER MIXING INTO THE STRONGER SOUTHWEST COMPONENTS ALOFT.
BY AFTERNOON THE DRY GUSTY SOUTHWEST WINDS SHOULD BE THE PRIMARY
WEATHER WITH MOISTURE CONTINUING TO ERODE SLOWLY THROUGH PARTS OF
THE ROLLING PLAINS AS WELL. CONSIDERABLE DISAGREEMENT REMAINS
BETWEEN MODEL CAMPS HOWEVER REGARDING NORTHWARD AND WESTWARD EXTENT
OF MIXED AIRMASS THROUGH THE ROLLING PLAINS. WE TEND TO LEAN TOWARDS
A MORE BACKED LOW LEVEL COMPONENT YET ARE NOT CONVINCED THAT AT
LEAST SOME PERIOD OF DEEP MIXING COULD ALSO WORK AS FAR NORTH AND
EAST AS CHILDRESS. A CONDITIONAL MENTION OF THUNDER AND SEVERE
STORMS WILL DEVELOP FROM THE FRONT AND DRY-LINE INTERSECTION
SOUTHWARD THROUGH EASTERN PORTIONS OF THE ROLLING PLAINS
ESPECIALLY...WHICH IS CONSISTENT WITH PREVIOUS FORECAST.
THUNDER CHANCES SHOULD INCREASE WITH ARRIVAL OF A STRONGER COLD
FRONT THIS EVENING THAT COULD FINALLY ALLOW CONVECTION TO DEEPEN AND
REALIZE THE CONSIDERABLE BUOYANT AND SHEARED ENVIRONMENT. THE SLOWLY
ERODING AND LIFTING CAP MAY STILL OFFER SOME RESISTANCE...HOWEVER...
THUS LIMITING CONFIDENCE FURTHER SOUTH THROUGH THE ROLLING PLAINS.
COLD FRONT WILL SURGE SOUTHWARD OVERNIGHT SPREADING LOW CLOUDS ONCE
MORE ACROSS MUCH OF THE AREA. WINDS MAY BECOME CLOSE TO WIND
ADVISORY LEVELS. PRECIPITATION CHANCES BEHIND THE FRONT APPEAR
SMALL...THOUGH WE RETAINED MINIMAL DRIZZLE MENTION NORTHERN ZONES
INCLUDING FREEZING DRIZZLE WITH TEMPERATURES EXPECTED TO DROP A
LITTLE BELOW FREEZING LATER TONIGHT ACROSS THE SOUTHWEST PANHANDLE
COUNTIES. RMCQUEEN
LONG TERM...
THURSDAY MORNING WILL START OFF BRISK ACROSS THE FAR SOUTHERN TEXAS
PANHANDLE...SOUTH PLAINS...AND ROLLING PLAINS BEHIND A STRONG COLD
FRONT EXHIBITING ABRUPT PRESSURE RISES. DO NOT BELIEVE WIND ADVISORY
CRITERIA WILL BE MET FOR AN EXTENDED PERIOD GIVEN AN OVERNIGHT
FRONTAL PASSAGE AND H70 200 NAUTICAL MILE HEIGHT GRADIENTS
SUPPORTING WINDS TOPPING OUT NEAR THE LOW END THRESHOLD OF 30 MPH.
SKIES SHOULD QUICKLY CLEAR AS DRIER AIR FILTERS IN ALONG WITH STOUT
COLD AIR ADVECTION ONLY ALLOWING HIGH TEMPERATURES TO REACH THE
UPPER 40S NORTHWEST TO MID-UPPER 50S SOUTHEAST. WINDS WILL DECREASE
THROUGH THE AFTERNOON AS JET MAX ALOFT PUSHES EAST AND PRESSURE
GRADIENT WEAKENS AHEAD OF APPROACHING SURFACE RIDGE FROM THE
ROCKIES. WHILE PORTIONS OF THE CAPROCK NORTH AND WEST OF LUBBOCK MAY
SEE FREEZING TEMPERATURES THURSDAY MORNING...A WIDESPREAD AND MUCH
HARDER FREEZE WILL TAKE PLACE FRIDAY MORNING AS CLEAR SKIES...LIGHT
WINDS...AND DRY CONDITIONS PROMOTE STRONG RADIATIONAL COOLING WITH
SURFACE RIDGING EXTENDING ACROSS THE AREA. NORTHWEST ZONES WILL
LIKELY BOTTOM OUT IN THE MID 20S WHILE UPPER 20S TO LOW 30S OCCUR
ELSEWHERE. FORECASTING LUBBOCK AND CHILDRESS TO BOTH BREAK THEIR
RECORD LOWS OF 31 AND 35 RESPECTIVELY. WILL CONTINUE TO MONITOR
TRENDS FOR FREEZE WATCH ISSUANCE AND HOLD OFF FOR NOW TO ALLOW THE
WEATHER SCENARIO FOR TODAY/TONIGHT DISCUSSED IN THE SHORT TERM TO
PLAY OUT.
NORTHWEST FLOW AND RISING HEIGHTS WILL TAKE PLACE ALOFT IN WAKE OF
THE EXITING UPPER TROUGH AND GENERATE LEE TROUGHING ACROSS SOUTHEAST
COLORADO AND NORTHEAST NEW MEXICO FRIDAY...BACKING WINDS
SOUTH/SOUTHWESTERLY AND SUBSEQUENTLY WARMING TEMPERATURES BACK INTO
THE 60S WITH OVERNIGHT LOWS FRIDAY INTO SATURDAY REMAINING ABOVE THE
FREEZING MARK. WARMING LOOKS TO CONTINUE INTO THE WEEKEND BEFORE A
SUBTLE SHORTWAVE TROUGH BACKS THE UPPER FLOW AND SENDS A WEAK COOL
FRONT/WIND SHIFT TOWARD THE REGION...POSSIBLY STALLING BEFORE
CLEARING THE ROLLING PLAINS. THUS...DO NOT EXPECT HIGHS TO TAKE MUCH
OF A HIT FROM SATURDAY/S IN THE MID TO UPPER 70S.
MONDAY IS SETTING UP TO BE ANOTHER SEASONABLE DAY IN THE MID TO
UPPER 70S AS SOUTHERLY WINDS DRAW IN WARM AIR AHEAD OF A SURFACE LOW
NEAR THE TEXAS PANHANDLE. AN UPPER TROUGH DIGGING OUT OF THE
INTERMOUNTAIN WEST WILL BE APPROACHING ALOFT AND PROVIDING SOME
LARGE SCALE FORCING FOR ASCENT. WILL HAVE TO SEE HOW MOISTURE RETURN
PLAYS OUT AS TO WHETHER STORMS WILL BE POSSIBLE...MOST LIKELY IN THE
FAR SOUTHEAST PANHANDLE AND ROLLING PLAINS. WILL KEEP THE FORECAST
DRY AT THIS POINT GIVEN NWP INCONSISTENCIES IN THE INTENSITY OF THE
TROUGH AND ASSOCIATED COLD FRONT. NONETHELESS...TUESDAY LOOKS COOLER
ONCE AGAIN BEFORE TEMPERATURES REBOUND INTO MID-LATE WEEK AS HEIGHTS
INCREASE ALOFT.
FIRE WEATHER...
THERE APPEARS TO BE LITTLE DISAGREEMENT THAT STRONG SOUTHWEST WINDS
WILL DEVELOP FOR MOST IF NOT ALL LOCATIONS ON THE CAP-ROCK THIS
AFTERNOON LASTING INTO THE EARLY EVENING. THE PERIOD WITH STRONGEST
WINDS SHOULD BE LATE IN THE AFTERNOON PERHAPS INTO THE EARLY
EVENING. THERE REMAINS UNCERTAINTY...HOWEVER...ABOUT POTENTIAL FOR
THE STRONG DRY WINDS TO SCOUR OUT THE MOISTURE OVER THE ROLLING
PLAINS. WE FAVOR A BLEND THAT RETAINS A SOMEWHAT BACKED LOW LEVEL
FLOW ACROSS THE ROLLING PLAINS...ESPECIALLY THE FAR EASTERN ROW OF
COUNTIES THROUGH THE AFTERNOON. THIS STILL MAY ALLOW ELEVATED AND
EVEN BRIEFLY CRITICAL FIRE WEATHER CONDITIONS TO DEVELOP FROM
BRISCOE AND HALL COUNTIES SOUTHWARD THROUGH KENT COUNTY. FUEL LOADS
REMAIN MINIMAL BUT THE ENERGY RELEASE COMPONENTS HAVE BECOME MORE
ELEVATED. SO...WE WILL ISSUE A RED FLAG WARNING FOR AREAS ON THE
CAPROCK WITH A FIRE DANGER STATEMENT FOR PORTIONS OF THE ROLLING
PLAINS AS WELL. RMCQUEEN
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 81 30 48 24 60 / 0 10 0 0 0
TULIA 84 31 49 25 61 / 10 10 0 0 0
PLAINVIEW 86 34 51 26 61 / 10 10 0 0 0
LEVELLAND 85 34 54 28 63 / 0 0 0 0 0
LUBBOCK 87 37 54 29 62 / 10 0 0 0 0
DENVER CITY 85 39 55 29 62 / 0 0 0 0 0
BROWNFIELD 86 39 55 30 62 / 0 0 0 0 0
CHILDRESS 78 37 53 30 64 / 30 40 0 0 0
SPUR 89 41 55 30 64 / 20 20 0 0 0
ASPERMONT 87 47 57 31 65 / 20 40 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: TXZ021>023-027>030-033>036-039>042.
&&
$$
33
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1211 AM CDT WED APR 17 2013
.DISCUSSION...
THIS MODEL RUN CONTINUES TO BRING MVFR CEILINGS BACK TO WEST
CENTRAL TEXAS DURING THE NEXT SEVERAL HOURS. SEE AVIATION BELOW
FOR MORE INFORMATION.
&&
.AVIATION...
MODELS THIS CYCLE INDICATE LITTLE NEED FOR CHANGES TO THE
TERMINALS. I DID ADJUST THE ONSET TIMING OF THE STRATUS BASED ON
SATELLITE DATA. HOWEVER...I STILL ANTICIPATE MVFR CEILINGS ACROSS
ALL OF WEST CENTRAL TEXAS BY 12Z TOMORROW MORNING. FLIGHT WEATHER
CONDITIONS SHOULD RETURN TO VFR BY 18Z...AS MIXING OF DRIER AIR
ALOFT BREAKS THE STRATUS CEILING. AS FOR THUNDERSTORMS TOMORROW
AFTERNOON AND EVENING...THE NAM AND GFS THIS CYCLE CONTINUE TO
SHOW DIFFERENT SOLUTIONS. THE NAM IS DRY UNTIL AFTER 06Z TOMORROW
NIGHT...WHILE THE GFS DOES INDICATE POSSIBLE CONVECTION ACROSS THE
BIG COUNTRY BETWEEN 00 AND 06Z. GIVEN THESE DIVERGING SOLUTIONS...I
DECIDED TO NOT INCLUDE ANY THUNDER IN ANY OF THE TERMINALS THIS
CYCLE.
HUBER
&&
.PREV DISCUSSION... /ISSUED 1148 PM CDT TUE APR 16 2013/
DISCUSSION...
HAVE REMOVED MENTION OF PRECIPITATION FROM THE FORECAST. WE MAY
SEE SOME LIGHT DRIZZLE OR FOG NORTH OF INTERSTATE 20 LATER TONIGHT
NEAR THE STALLED COLD FRONTAL BOUNDARY...BUT NOT EXPECTING ANY
SIGNIFICANT PRECIPITATION TO DEVELOP THROUGH THE REST OF THE
OVERNIGHT HOURS AT THIS TIME. 20
PREV DISCUSSION... /ISSUED 644 PM CDT TUE APR 16 2013/
DISCUSSION...
LOOK FOR CHALLENGING FLIGHT WEATHER CONDITIONS TO DEVELOP ACROSS
WEST CENTRAL TEXAS DURING THE NEXT 6 HOURS. AVIATION BELOW HAS
DETAILS.
AVIATION...
MODELS THIS CYCLE CONTINUE TO INDICATE STRATUS AND MVFR CEILINGS
WILL RETURN TO ALL OF WEST CENTRAL TEXAS BY 06Z TONIGHT. THE NAM
AND GFS 925 MB RELATIVE HUMIDITY FIELDS INCREASE TO NEAR
SATURATION BY 06Z ACROSS ALL OF WEST CENTRAL TEXAS. PLUS...THE GFS
AND NAM MOS GUIDANCE BOTH HOLD MVFR CEILINGS AT ALL FIVE TERMINALS
WELL INTO TOMORROW AFTERNOON. OUR PREVIOUS AVIATION FORECAST
PACKAGE RETURNED VFR CONDITIONS TO ALL FIVE TERMINALS BY 15Z
TOMORROW MORNING. HOWEVER...ALL INDICATORS SUGGEST THE MVFR
CEILINGS WILL LIKELY HOLD UNTIL AROUND 18Z TOMORROW AFTERNOON.
SO...THE NEW TERMINALS HOLD MVFR CEILINGS UNTIL 18Z.
ALSO...A WEAK FRONTAL BOUNDARY HAS STALLED NEAR A SWEETWATER TO
ALBANY LINE. THIS SURFACE BOUNDARY MAY INITIATE SHOWERS AND
THUNDERSTORMS LATER THIS EVENING. HOWEVER...I DECIDED NOT TO
INCLUDE ANY THUNDER IN THE ABILENE TERMINAL BECAUSE MY CONFIDENCE
FOR WHEN AND WHERE THIS CONVECTION MAY INITIATE IS NOT VERY HIGH.
HUBER
PREV DISCUSSION... /ISSUED 340 PM CDT TUE APR 16 2013/
SHORT TERM...
FRONTAL BOUNDARY HAS SAGGED SOUTH THROUGH THE INTERSTATE 20 CORRIDOR
THIS AFTERNOON...WITH NORTH WINDS AT SWEETWATER AND BRIEFLY AT
ABILENE. LOOKS LIKE THE FRONT HAS PULLED UP STATIONARY OR MAYBE
DRIFTING WEST...WITH MODELS SUGGESTING A RETREAT NORTHWARD AS A WARM
FRONT THIS EVENING. HOW FAR NORTH IT RETREATS IS A HUGE
QUESTION...WITH THE GFS SHOWING A RAPID RETREAT AND THE RUC MUCH
SLOWER. AT THIS POINT...WITH THE GFS HAVING LARGELY MISSED HOW FAR
SOUTH THE FRONT WOULD MAKE IT TODAY...AND WITH TEMPERATURES IN THE
50S AND STILL GOOD NORTHEAST FLOW ACROSS OKLAHOMA...WILL LEAN
TOWARDS A SOMEWHAT SLOWER RETREAT.
VISIBLE SATELLITE SHOWING A LITTLE CU TRYING TO GO ALONG AND JUST
NORTH OF THE FRONT ACROSS THE BIG COUNTRY. CAP IS STILL STRONG...BUT
AT LEAST A FEW STORMS LOOK VERY POSSIBLE...AS THE CAP WEAKENS
LOCALLY AND AS A WEAK UPPER LEVEL SHORTWAVE APPROACHES. EXPECT A FEW
ISOLATED STORMS TO DEVELOP SOMEWHERE CLOSE TO ABILENE OR SWEETWATER
LATE THIS AFTERNOON AND CONTINUE INTO THE MID EVENING HOURS. NEAR
RECORD HIGH TEMPERATURES HERE IN SAN ANGELO...ALONG WITH DEWPOINTS
AROUND 60...ARE LEADING TO A VERY UNSTABLE AIR MASS. GIVEN CAPE
VALUES IN EXCESS OF 2500 J/KG...IF A STORM CAN DEVELOP...EXPECT IT
TO TRY TO REACH SEVERE LEVELS PRETTY QUICK.
EXPECT FRONT TO DRIFT NORTH THROUGH THE EVENING...PROBABLY BACK INTO
THE NORTHERN BIG COUNTRY BY LATE THIS EVENING...AND BACK OUT OF WEST
CENTRAL TEXAS BY SUNRISE. MILD AGAIN SOUTH OF THE BOUNDARY...WITH
READINGS HAVING A HARD TIME DROPPING BELOW 70. A LITTLE COOLER
ACROSS THE NORTHERN BIG COUNTRY...ALTHOUGH TEMPERATURES THERE MAY
EVEN CLIMB SLIGHTLY BY MORNING.
MAIN UPPER TROUGH MOVING INTO THE ROCKIES WEDNESDAY AFTERNOON. BEST
LIFT WAITS UNTIL WEDNESDAY NIGHT...BUT IT WILL AID THE DRYLINE IN
STRENGTHENING AND MOVING EAST. BY AFTERNOON...DRYLINE WILL LIKELY BE
SOMEWHERE ACROSS THE WESTERN BIG COUNTRY AND CONCHO VALLEY. CAP WILL
STILL BE STRONG...BUT SHOULD BEGIN TO ERODE BY LATE IN THE
AFTERNOON. WILL CONTINUE THE SLIGHT CHANCE POPS DURING THE
AFTERNOON...WITH ODDS INCREASING QUITE A BIT AFTER DARK.
07
LONG TERM...
CURRENT WEATHER...WV IMAGERY IS SHOWING A TROF AMPLIFYING ACROSS THE
WESTERN US. THIS AFTERNOON...STATIONARY FRONT EXTENDS ACROSS
EXTREME SOUTHEAST OKLAHOMA...NORTHWEST TEXAS AND THE NORTHERN
PERMIAN BASIN. ALSO...MODIFIED ARCTIC HIGH PRESSURE SURFACE RIDGE
WAS OVER MONTANA AND THE NORTHERN PLAINS.
WEDNESDAY NIGHT...HOW ARE THESE TWO FEATURES GOING TO AFFECT WEST
CENTRAL TEXAS WITH POSSIBLE SEVERE WEATHER. THE ALOFT PART IS
PRETTY STRAIGHT FORWARD...WITH TROF INTENSIFYING AND MOVING EAST
PUTTING THE SOUTHERN PLAINS IN STRONG SOUTHWEST FLOW. ALSO...THE
GFS MODEL INDICATING GOOD POLAR AND SUBTROPICAL JET DIVERGENCE AT
POSSIBLE PRIME SEVERE WEATHER TIME/WEDNESDAY AFTERNOON AND NIGHT/.
THE SURFACE PART IS MORE COMPLEX. THE ECMWF AND NAM MODELS ARE
KEEPING THE FRONT FURTHER SOUTH FROM ALONG AN OKLAHOMA CITY TO
TULIA LINE THROUGH WEDNESDAY. THE GFS IS MUCH FURTHER NORTH ALONG
A GUYMON TO KANSAS CITY LINE. THE GFS MAY BE STRUGGLING DUE
PARTLY TO THE WARM EQUATION NUMBERS BEING INPUTED ON APRIL 1ST.
GOING MORE WITH THE NAM AND ECMWF DUE TO ARCTIC AIR ALREADY IN
PLACE TO OUR NORTH AND A NEGATIVE NAO PATTERN STILL OVER THE
EASTERN US. HOWEVER...GOOD SURFACE CYCLOGENESIS IS A GOOD BET
WEDNESDAY OVER THE SOUTHERN PLAINS DUE TO STRONG DYNAMICS JUST
UPSTREAM. THERE ARE A FEW MORE TWISTS AND TURNS IN THIS FORECAST.
STAY TUNED.
THE BEST CHANCE OF MORE WIDESPREAD/POSSIBLY SIGNIFICANT/SEVERE
WEATHER WILL BE WEDNESDAY AND WEDNESDAY NIGHT ACROSS THE SOUTHERN
PLAINS. THE DAY2 OUTLOOK BY SPC OF A MODERATE RISK OVER OKLAHOMA
AND EXTREME NORTHWEST TEXAS LOOKS GOOD. THE WARM SECTOR WILL BE
PRIMED AHEAD OF THE DRYLINE AND SOUTH OF STATIONARY FRONT.
DEWPOINTS WILL BE IN THE MID TO UPPER 60S ALONG WITH STRONG
INSTABILITY/MLCAPES OF 2000 TO 3000 J/KG/. WITH THE ADDITION OF
STRONG SHEAR...SUPERCELLS ARE A GOOD BET MAINLY DURING THE LATE
AFTERNOON AND EARLY EVENING. AT LEAST FOR NOW...THE FRONT WILL
MOVE NORTH TO THE I-40 CORRIDOR BY 00Z THU. SO MORE ORGANIZED
SEVERE CONVECTION IS MORE LIKELY ACROSS THE BIG COUNTRY LATE
WEDNESDAY AFTERNOON AND EVENING. ALSO...THE TEXAS TECH 3KM WRF IS
INDICATING A LINE OF CONVECTION FROM ABILENE TO SAN ANGELO JUST
AFTER MIDNIGHT. THE MAIN HAZARDS WILL BE LARGE HAIL AND DAMAGING
WINDS...ALONG WITH ISOLATED TORNADOES POSSIBLE. GOING WITH LKLY
POPS ACROSS THE FAR EASTERN COUNTIES AND MAINLY CHC ELSEWHERE FOR
WEDNESDAY NIGHT.
THURSDAY THROUGH TUESDAY...COOLER FOR THURSDAY AND FRIDAY WITH
HIGHS MAINLY IN THE 60S. A WARMING TREND BY THIS WEEKEND WITH
HIGHS IN THE UPPER 70S TO LOWER 80S. THE COLDEST MORNING WILL BE
FRIDAY WITH LOWS IN THE 30S. IF SKIES ARE CLEAR AND WINDS
CALM...THEN TEMPS MAY DROP TO NEAR FREEZING...ESPECIALLY IN LOW
LYING AREAS AND RIVER VALLEYS.
21
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 56 62 36 62 41 / 40 10 5 5 0
SAN ANGELO 58 65 38 67 43 / 30 10 5 5 0
JUNCTION 63 70 39 67 41 / 50 10 5 5 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
HUBER
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
1148 PM CDT TUE APR 16 2013
.DISCUSSION...
HAVE REMOVED MENTION OF PRECIPITATION FROM THE FORECAST. WE MAY
SEE SOME LIGHT DRIZZLE OR FOG NORTH OF INTERSTATE 20 LATER TONIGHT
NEAR THE STALLED COLD FRONTAL BOUNDARY...BUT NOT EXPECTING ANY
SIGNIFICANT PRECIPITATION TO DEVELOP THROUGH THE REST OF THE
OVERNIGHT HOURS AT THIS TIME. 20
&&
.PREV DISCUSSION... /ISSUED 644 PM CDT TUE APR 16 2013/
DISCUSSION...
LOOK FOR CHALLENGING FLIGHT WEATHER CONDITIONS TO DEVELOP ACROSS
WEST CENTRAL TEXAS DURING THE NEXT 6 HOURS. AVIATION BELOW HAS
DETAILS.
AVIATION...
MODELS THIS CYCLE CONTINUE TO INDICATE STRATUS AND MVFR CEILINGS
WILL RETURN TO ALL OF WEST CENTRAL TEXAS BY 06Z TONIGHT. THE NAM
AND GFS 925 MB RELATIVE HUMIDITY FIELDS INCREASE TO NEAR
SATURATION BY 06Z ACROSS ALL OF WEST CENTRAL TEXAS. PLUS...THE GFS
AND NAM MOS GUIDANCE BOTH HOLD MVFR CEILINGS AT ALL FIVE TERMINALS
WELL INTO TOMORROW AFTERNOON. OUR PREVIOUS AVIATION FORECAST
PACKAGE RETURNED VFR CONDITIONS TO ALL FIVE TERMINALS BY 15Z
TOMORROW MORNING. HOWEVER...ALL INDICATORS SUGGEST THE MVFR
CEILINGS WILL LIKELY HOLD UNTIL AROUND 18Z TOMORROW AFTERNOON.
SO...THE NEW TERMINALS HOLD MVFR CEILINGS UNTIL 18Z.
ALSO...A WEAK FRONTAL BOUNDARY HAS STALLED NEAR A SWEETWATER TO
ALBANY LINE. THIS SURFACE BOUNDARY MAY INITIATE SHOWERS AND
THUNDERSTORMS LATER THIS EVENING. HOWEVER...I DECIDED NOT TO
INCLUDE ANY THUNDER IN THE ABILENE TERMINAL BECAUSE MY CONFIDENCE
FOR WHEN AND WHERE THIS CONVECTION MAY INITIATE IS NOT VERY HIGH.
HUBER
PREV DISCUSSION... /ISSUED 340 PM CDT TUE APR 16 2013/
SHORT TERM...
FRONTAL BOUNDARY HAS SAGGED SOUTH THROUGH THE INTERSTATE 20 CORRIDOR
THIS AFTERNOON...WITH NORTH WINDS AT SWEETWATER AND BRIEFLY AT
ABILENE. LOOKS LIKE THE FRONT HAS PULLED UP STATIONARY OR MAYBE
DRIFTING WEST...WITH MODELS SUGGESTING A RETREAT NORTHWARD AS A WARM
FRONT THIS EVENING. HOW FAR NORTH IT RETREATS IS A HUGE
QUESTION...WITH THE GFS SHOWING A RAPID RETREAT AND THE RUC MUCH
SLOWER. AT THIS POINT...WITH THE GFS HAVING LARGELY MISSED HOW FAR
SOUTH THE FRONT WOULD MAKE IT TODAY...AND WITH TEMPERATURES IN THE
50S AND STILL GOOD NORTHEAST FLOW ACROSS OKLAHOMA...WILL LEAN
TOWARDS A SOMEWHAT SLOWER RETREAT.
VISIBLE SATELLITE SHOWING A LITTLE CU TRYING TO GO ALONG AND JUST
NORTH OF THE FRONT ACROSS THE BIG COUNTRY. CAP IS STILL STRONG...BUT
AT LEAST A FEW STORMS LOOK VERY POSSIBLE...AS THE CAP WEAKENS
LOCALLY AND AS A WEAK UPPER LEVEL SHORTWAVE APPROACHES. EXPECT A FEW
ISOLATED STORMS TO DEVELOP SOMEWHERE CLOSE TO ABILENE OR SWEETWATER
LATE THIS AFTERNOON AND CONTINUE INTO THE MID EVENING HOURS. NEAR
RECORD HIGH TEMPERATURES HERE IN SAN ANGELO...ALONG WITH DEWPOINTS
AROUND 60...ARE LEADING TO A VERY UNSTABLE AIR MASS. GIVEN CAPE
VALUES IN EXCESS OF 2500 J/KG...IF A STORM CAN DEVELOP...EXPECT IT
TO TRY TO REACH SEVERE LEVELS PRETTY QUICK.
EXPECT FRONT TO DRIFT NORTH THROUGH THE EVENING...PROBABLY BACK INTO
THE NORTHERN BIG COUNTRY BY LATE THIS EVENING...AND BACK OUT OF WEST
CENTRAL TEXAS BY SUNRISE. MILD AGAIN SOUTH OF THE BOUNDARY...WITH
READINGS HAVING A HARD TIME DROPPING BELOW 70. A LITTLE COOLER
ACROSS THE NORTHERN BIG COUNTRY...ALTHOUGH TEMPERATURES THERE MAY
EVEN CLIMB SLIGHTLY BY MORNING.
MAIN UPPER TROUGH MOVING INTO THE ROCKIES WEDNESDAY AFTERNOON. BEST
LIFT WAITS UNTIL WEDNESDAY NIGHT...BUT IT WILL AID THE DRYLINE IN
STRENGTHENING AND MOVING EAST. BY AFTERNOON...DRYLINE WILL LIKELY BE
SOMEWHERE ACROSS THE WESTERN BIG COUNTRY AND CONCHO VALLEY. CAP WILL
STILL BE STRONG...BUT SHOULD BEGIN TO ERODE BY LATE IN THE
AFTERNOON. WILL CONTINUE THE SLIGHT CHANCE POPS DURING THE
AFTERNOON...WITH ODDS INCREASING QUITE A BIT AFTER DARK.
07
LONG TERM...
CURRENT WEATHER...WV IMAGERY IS SHOWING A TROF AMPLIFYING ACROSS THE
WESTERN US. THIS AFTERNOON...STATIONARY FRONT EXTENDS ACROSS
EXTREME SOUTHEAST OKLAHOMA...NORTHWEST TEXAS AND THE NORTHERN
PERMIAN BASIN. ALSO...MODIFIED ARCTIC HIGH PRESSURE SURFACE RIDGE
WAS OVER MONTANA AND THE NORTHERN PLAINS.
WEDNESDAY NIGHT...HOW ARE THESE TWO FEATURES GOING TO AFFECT WEST
CENTRAL TEXAS WITH POSSIBLE SEVERE WEATHER. THE ALOFT PART IS
PRETTY STRAIGHT FORWARD...WITH TROF INTENSIFYING AND MOVING EAST
PUTTING THE SOUTHERN PLAINS IN STRONG SOUTHWEST FLOW. ALSO...THE
GFS MODEL INDICATING GOOD POLAR AND SUBTROPICAL JET DIVERGENCE AT
POSSIBLE PRIME SEVERE WEATHER TIME/WEDNESDAY AFTERNOON AND NIGHT/.
THE SURFACE PART IS MORE COMPLEX. THE ECMWF AND NAM MODELS ARE
KEEPING THE FRONT FURTHER SOUTH FROM ALONG AN OKLAHOMA CITY TO
TULIA LINE THROUGH WEDNESDAY. THE GFS IS MUCH FURTHER NORTH ALONG
A GUYMON TO KANSAS CITY LINE. THE GFS MAY BE STRUGGLING DUE
PARTLY TO THE WARM EQUATION NUMBERS BEING INPUTED ON APRIL 1ST.
GOING MORE WITH THE NAM AND ECMWF DUE TO ARCTIC AIR ALREADY IN
PLACE TO OUR NORTH AND A NEGATIVE NAO PATTERN STILL OVER THE
EASTERN US. HOWEVER...GOOD SURFACE CYCLOGENESIS IS A GOOD BET
WEDNESDAY OVER THE SOUTHERN PLAINS DUE TO STRONG DYNAMICS JUST
UPSTREAM. THERE ARE A FEW MORE TWISTS AND TURNS IN THIS FORECAST.
STAY TUNED.
THE BEST CHANCE OF MORE WIDESPREAD/POSSIBLY SIGNIFICANT/SEVERE
WEATHER WILL BE WEDNESDAY AND WEDNESDAY NIGHT ACROSS THE SOUTHERN
PLAINS. THE DAY2 OUTLOOK BY SPC OF A MODERATE RISK OVER OKLAHOMA
AND EXTREME NORTHWEST TEXAS LOOKS GOOD. THE WARM SECTOR WILL BE
PRIMED AHEAD OF THE DRYLINE AND SOUTH OF STATIONARY FRONT.
DEWPOINTS WILL BE IN THE MID TO UPPER 60S ALONG WITH STRONG
INSTABILITY/MLCAPES OF 2000 TO 3000 J/KG/. WITH THE ADDITION OF
STRONG SHEAR...SUPERCELLS ARE A GOOD BET MAINLY DURING THE LATE
AFTERNOON AND EARLY EVENING. AT LEAST FOR NOW...THE FRONT WILL
MOVE NORTH TO THE I-40 CORRIDOR BY 00Z THU. SO MORE ORGANIZED
SEVERE CONVECTION IS MORE LIKELY ACROSS THE BIG COUNTRY LATE
WEDNESDAY AFTERNOON AND EVENING. ALSO...THE TEXAS TECH 3KM WRF IS
INDICATING A LINE OF CONVECTION FROM ABILENE TO SAN ANGELO JUST
AFTER MIDNIGHT. THE MAIN HAZARDS WILL BE LARGE HAIL AND DAMAGING
WINDS...ALONG WITH ISOLATED TORNADOES POSSIBLE. GOING WITH LKLY
POPS ACROSS THE FAR EASTERN COUNTIES AND MAINLY CHC ELSEWHERE FOR
WEDNESDAY NIGHT.
THURSDAY THROUGH TUESDAY...COOLER FOR THURSDAY AND FRIDAY WITH
HIGHS MAINLY IN THE 60S. A WARMING TREND BY THIS WEEKEND WITH
HIGHS IN THE UPPER 70S TO LOWER 80S. THE COLDEST MORNING WILL BE
FRIDAY WITH LOWS IN THE 30S. IF SKIES ARE CLEAR AND WINDS
CALM...THEN TEMPS MAY DROP TO NEAR FREEZING...ESPECIALLY IN LOW
LYING AREAS AND RIVER VALLEYS.
21
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 68 86 56 62 36 / 10 20 40 10 5
SAN ANGELO 70 91 58 65 38 / 10 20 30 10 5
JUNCTION 70 89 63 70 39 / 5 20 50 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1054 PM MDT THU APR 18 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 218 PM MDT THU APR 18 2013
EARLY AFTERNOON WV IMAGERY AND RUC H5 ANALYSIS SHOWS POSITIVELY
TILTED TROUGH EXTENDING FROM THE NORTHERN PLAINS ALONG KS/CO BORDER.
AT THE SURFACE HIGH PRESSURE IS IN PLACE OVER EASTERN
COLORADO...WITH A 996MB SURFACE LOW CENTERED OVER THE NORTHERN
MISSISSIPPI VALLEY. NORTHWEST GRADIENT IS IN PLACE AT THE SURFACE
ACROSS OUR CWA...WITH WINDS GUSTING TO 40 MPH.
SEVERAL LOCATIONS INCLUDING KGLD AND KITR HAVE REPORTED SUSTAINED
WINDS WITHIN ADVISORY CRITERIA THIS AFTERNOON. THESE WINDS HAVE BEEN
SHORT LIVED AT THESE LOCATIONS WITH THE OVERALL TREND ACROSS THE
AREA TO REMAIN BELOW ADVISORY CRITERIA...SO NO HIGHLIGHT PLANNED AT
THIS POINT. THERE WAS SOME CONCERN THAT THERE WOULD BE PATCHY
BLOWING SNOW WITH THESE WINDS...AND TO THIS POINT NO REPORTS OF
REDUCED VISIBILITIES HAVE BEEN REPORTED SO FAR THIS AFTERNOON. WITH
FRESHLY FALLEN SNOW AND GUSTS TO 40 MPH I STILL COULDNT RULE THIS
OUT THIS AFTERNOON ESPECIALLY ACROSS OPEN AREAS IN THE COUNTRY SO I
PLAN ON LEAVING PATCHY BLOWING SNOW MENTION IN PLACE THROUGH THE
AFTERNOON HOURS.
OTHER IMMEDIATE FORECAST CONCERN THIS AFTERNOON IS POTENTIAL FOR
FLURRIES (OR SPRINKLES WHERE SURFACE TEMPS ARE ABOVE FREEZING).
RADAR CONTINUES TO SHOW LIGHT RETURNS ACROSS OUR FORECAST
AREA...ASSOCIATED WITH BANDS OF STRATOCUMULUS THAT HAS DEVELOPED
WITH COLD POOL ON BACK SIDE OF UPPER LOW. THERE HAVE BEEN NO RECENT
REPORTS OF PRECIP...HOWEVER I COULDNT RULE OUT NON MEASURABLE
BEFORE SUNSET.
TONIGHT-FRIDAY...WINDS SHOULD DIMINISH AFTER SUNSET AND WITH
UNSEASONABLY COOL AIR MASS IN PLACE AND CLEARING SKIES WE COULD END
UP WITH NEAR RECORD LOW TEMPS AT A FEW LOCATIONS (ESPECIALLY IF
WINDS GO CALM). WINDS SHOULD STILL BE IN THE 10-15 MPH RANGE WHICH
SHOULD LIMIT COOLING. I KEPT FORECAST IN THE UPPER TEENS-LOW 20S FOR
MOST OF THE AREA...WHICH IS ABOVE PREVIOUS DAILY RECORDS. DRY
CONDITIONS AND MILD TEMPS ARE EXPECTED THROUGH THE DAY THU WITH W/NW
FLOW ALOFT AND LEE TROUGH REBUILDING. MODEL SOUNDINGS ARE DRY
ADIABATIC TO ABOUT 700MB AND IF IT WASNT FOR RECENT SNOWFALL I MIGHT
BE CONCERNED WITH POTENTIAL RFW CONDITIONS FRI AFTERNOON.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 218 PM MDT THU APR 18 2013
FORECAST PROBLEMS WILL BE HOW MUCH IT WARMS UP THROUGH THE WEEKEND
BEFORE THE NEXT COLD FRONT MOVES THROUGH AND THE PRECIPITATION
CHANCES THIS WEEKEND AND CONTINUING INTO THE BEGINNING OF NEXT WEEK.
SATELLITE SHOWING THE LARGE SCALE FLOW PATTERN BEING AMPLIFIED AND
BLOCKY FROM THE PACIFIC INTO THE EASTERN NORTH AMERICA. SYSTEM THAT
HAS BROUGHT 2 TO 5 INCHES OF SNOW AND A LOT OF WIND TO THE AREA IS
CONTINUING TO MOVE TOWARD THE EAST. COLD AIR MASS HAS SETTLED OVER
THE REGION.
MODELS APPEAR TO START OUT FINE ON THE UPPER JET. WITH OUR EXITING
SYSTEM AND OVERALL MID LEVELS...THE UKMET WAS DOING A LITTLE BETTER
THAN THE ECMWF AND THE CANADIAN. NAM/ECMWF WERE DOING THE BEST ON
THE SURFACE PRESSURE/WIND FIELD. THE NAM WAS DOING SLIGHTLY BETTER
THAN THE GFS AND SREF ON THE LOW LEVEL THERMAL FIELD.
FRIDAY NIGHT...LEFT FRONT QUADRANT OF THE JET IS NOW MUCH FURTHER
SOUTHWEST OF THE AREA THAT WHAT THE MODELS WERE SHOWING 24 HOURS
AGO. ALSO MID LEVEL LIFT IS BETTER ON EITHER SIDE...ESPECIALLY TO
THE SOUTH. SO WILL KEEP THIS PERIOD DRY. WINDS WILL BECOME LIGHT AND
VARIABLE. AT THE SAME TIME...MID AND HIGH LEVEL CLOUD COVER BECOME
RATHER THICK. SO EXPECT THE CLOUD COVER TO KEEP THE TEMPERATURES FROM
DROPPING TOO MUCH.
SATURDAY/SATURDAY NIGHT...MAIN JET IS STILL FAR TO THE SOUTHWEST OF
THE AREA. MIXED SIGNALS ON CHANCE OF PRECIPITATION. MOISTURE REMAINS
ABOVE 700 MB WITH ONLY WEAK MID LEVEL LIFT IN PLACE. THETA-E LAPSE
RATES ARE GOOD WITH LITTLE TO NO SURFACE/ELEVATED CAPE IN PLACE.
MODELS HAVE LIGHT QPF SCATTERED ALL OVER THE PLACE. FEELING IS THAT
NOT MUCH IS GOING TO REACH THE GROUND. SO REMOVED POPS AND REPLACED
THE AFTERNOON/EVENING WEATHER GRIDS WITH SPRINKLES.
SNOW IS EXPECTED TO MELT PRETTY QUICK SO DO NOT THINK THERE WILL BE
MUCH IF ANY AFFECT ON THE TEMPERATURES. MODELS ARE ALL OVER THE PLACE
WITH THE WIND FIELD. CONSIDERING THE NUMEROUS SHORTWAVE TROUGHS
EMBEDDED WITHIN THE FAST WESTERLY FLOW ALOFT...CAN UNDERSTAND THE
MODEL DIFFICULTIES. OVERALL CONSENSUS WITH THE LIGHT FIELD IS TO HAVE
WINDS FROM AN UPSLOPE DIRECTION. SO THE WINDS WILL NOT HELP WITH THE
WARMUP. AND CONSIDERING THE RATHER THICK CLOUD COVER...AM NOT SOLD ON
A BIG WARM UP. HOWEVER...MODELS HAVE BEEN UNDERDOING WARMUPS RECENTLY
AND CONSIDERING POSSIBLE SNOW FIELD CONTAMINATION...THAT COULD BE THE
CASE HERE. RIGHT NOW WILL GO NEAR THE WARMEST GUIDANCE.
SAME THING WITH THE WIND FIELD FOR THE NIGHT PERIOD WITH WINDS
RATHER LIGHT AND VARIABLE. WILL HAVE DECENT MID/UPPER LEVEL CLOUD
COVER UNTIL LATE IN THE NIGHT. IT LOOKS LIKE THE MINS WILL BE
WARMER DUE TO THE CLOUDS BUT CAN SEE WHERE MINS COULD REALLY DROP
OFF.
SUNDAY...WITH THE EXCEPTION OF THE NAM...MODELS ARE IN AGREEMENT IN
HAVING THE LEFT FRONT QUADRANT OF A STRONG UPPER JET AFFECTING THE
WEST/SOUTHWEST PORTION OF THE AREA IN THE AFTERNOON. THE MODELS HAVE
LESS MOISTURE AROUND THAN THE PREVIOUS DAY. BUT CANNOT IGNORE THIS
INCOMING JET. SOME OF THE MODEL OUTPUT IS PRODUCING LIGHT QPF. SO
AT THIS TIME HAVE PUT IN A SLIGHT CHANCE IN THE AFTERNOON. THIS
TRANSITIONS WELL INTO WHAT THE INIT HAS GIVEN ME FOR SUNDAY NIGHT.
MODEL WIND FIELDS CONTINUE TO BE IN CHAOS AND DISAGREEMENT...WHICH
PROBABLY MEANS LIGHT AND VARIABLE. THIS WIND DISAGREEMENT TRANSLATES
INTO LOW LEVEL THERMAL DISAGREEMENT. THERE LOOKS LIKE THERE WILL BE
MORE SUN THAN THE PREVIOUS FEW DAYS PLUS WINDS MAY END UP DOWNSLOPE.
SO RAISED MAXES SOME.
SUNDAY NIGHT THROUGH THURSDAY...LEFT FRONT QUADRANT/JET AXIS OF THE
ABOVE MENTIONED JET CONTINUES TO STRONGLY AFFECT THE AREA FROM
SUNDAY NIGHT THROUGH MONDAY NIGHT INTO EARLY TUESDAY MORNING. MODELS
ARE IN A LITTLE CLOSER AGREEMENT THAN YESTERDAY. THE ECMWF WHICH
HAS BEEN THE MOST CONSISTENT...HAS SLOWED DOWN/IS FURTHER NORTH WITH
INCOMING UPPER TROUGH. THE ECMWF IS ALSO SLOWER THAN THE REMAINING
MODEL OUTPUT.
SO LIKED AND ACCEPTED WHAT THE CRH INIT GAVE ME FOR POPS THROUGH
TUESDAY WHICH WAS NOT TOO DIFFERENT THAN WHAT THE INIT HAS BEEN
PRODUCING THE LAST COUPLE OF DAYS. SO THAT MEANS A CONTINUED GOOD
CHANCE OF PRECIPITATION FROM SUNDAY NIGHT AND ESPECIALLY MONDAY INTO
MONDAY NIGHT. PRECIPITATION ENDS TUESDAY WITH A DRY FORECAST FOR
TUESDAY NIGHT INTO WEDNESDAY. FOR THURSDAY MODELS AGREE WITH HAVING
NORTHWEST FLOW ALOFT OVER THE AREA WITH EMBEDDED SHORTWAVE TROUGH(S)
IN THIS FLOW...ALWAYS A DANGEROUS SCENARIO AND NEVER CAN RULE OUT ANY
PRECIPITATION. SO THE SLIGHT CHANCE THE INIT GAVE ME LOOKS
REASONABLE.
THANKS TO ALL FOR THE COLLABORATION WHO CHOSE TO COLLABORATE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1053 PM MDT THU APR 18 2013
A CLEAR SKY WILL PREVAIL AT KGLD AND KMCK OVERNIGHT AND FRIDAY
MORNING AS HIGH PRESSURE AND SUBSIDENCE MOVE INTO THE REGION. SOME
SCATTERED CLOUDS WILL DEVELOP FRIDAY AROUND MIDDAY WITH WIND
BECOMING BREEEZY. WIND WILL BECOME LIGHT AS THE ATMOSPHERE DECOUPLES
FRIDAY EVENING. MID LEVEL CLOUDS WILL INCREASE FRIDAY EVENING BUT
CONDITIONS WILL REMAIN VFR WITH NO PRECIPITATION EXPECTED.
&&
.CLIMATE...
ISSUED AT 315 AM MDT THU APR 18 2013
RECORD LOW TEMPERATURES FRIDAY MORNING:
GOODLAND.....18 DEGREES (1953)
HILL CITY....23 DEGREES (1953)
MCCOOK.......22 DEGREES (1953)
BURLINGTON...17 DEGREES (1966)
COLBY........19 DEGREES
TRIBUNE......19 DEGREES
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...FS
CLIMATE...DDT
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
936 PM EDT THU APR 18 2013
.SYNOPSIS...
HIGH PRESSURE SHIFTS FARTHER OFF THE COAST OVERNIGHT AS A STRONG
COLD FRONT MOVES ACROSS THE OHIO AND TENNESSEE VALLEYS. THIS COLD
FRONT WILL TRACK ACROSS THE MID ATLANTIC REGION FRIDAY NIGHT.
CANADIAN HIGH PRESSURE BUILDS ACROSS THE NORTHEAST OVER THE
WEEKEND AS A FRONTAL BOUNDARY REMAINS STALLED OFF THE SOUTHEAST
COAST.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE LATEST SURFACE ANALYSIS INDICATES A ~1030MB HIGH CENTERED JUST
OFFSHORE OF EASTERN NEW ENGLAND/ATLANTIC CANADA, WITH A DEEPENING
~992MB LOW PRESSURE CENTER TRACKING NNE FROM THE UPPER MIDWEST
TOWARDS THE UPPER GREAT LAKES THIS EVENING. THE ASSOCIATED COLD
FRONT EXTENDS SOUTHWARD THROUGH THE LOWER MISSISSIPPI
VALLEY...WITH A WARM FRONT EXTENDING ENE THROUGH THE GREAT LAKES
AND INTO SOUTHERN ONTARIO. ADDITIONALLY...THERE REMAINS A DIFFUSE
OLD FRONTAL BOUNDARY ALIGNED NW-SE ACROSS CENTRAL PA JUST OFFSHORE
OF THE LOWER MD EASTERN SHORE. PERSISTENT FOG AND STRATUS, WHICH
MARKED MUCH OF THE DAY ALONG THE IMMEDIATE COAST (OCEAN CITY AND
NORTH), FINALLY ABATED JUST BEFORE 22Z. HOWEVER, LATEST OBS IN THE
AREA INDICATE SOME BACKING OF LLVL WINDS, LKLY A PRECURSOR TO FOG
REDEVELOPING LATER THIS EVENING.
OVERNIGHT...
NUMERICAL AND STATISTICAL MODEL GUIDANCE REMAINS RATHER PESSIMISTIC
WITH RESPECT TO FOG AND STRATUS OVERNIGHT. HOWEVER...STRENGTHENING
SW FLOW ALOFT AND S/SE FLOW AT THE SURFACE AROUND THE WESTERN
PERIPHERY OF THE HIGH WOULD SUPPORT MORE OF A STRATUS SITUATION
RATHER THAN FOG. AT THIS TIME, PER LATEST SREF PROBABILITIES AND
RUC SOUNDINGS, CONFIDENCE IS HIGH THAT AREAS OF FOG WILL REDEVELOP
TOWARDS AND AFTER MIDNIGHT FOR THE IMMEDIATE ATLANTIC COAST (AND
ADJACENT COASTAL MARINE AREAS). ALL OF THE ABOVE GUIDANCE IS FAR
LESS EMPHATIC WITH FOG COVERAGE WEST OF HWY 13 ON THE LOWER
EASTERN SHORE, AGAIN INSTEAD FAVORING LOW STRATUS. THUS, WILL
MAINTAIN PATCHY FOG MENTION ELSEWHERE FOR THE EASTERN SHORE.
REGARDING POPS, GIVEN INCREASING MOIST SSE FLOW AROUND THE HIGH,
AND AHEAD OF THE APPROACHING FRONT TO THE WEST, SOME ISOLATED
SHRAS/SPRINKLES ACRS THE PIEDMONT WILL BE POSSIBLE TOWARDS DAWN
FRIDAY MORNING AS BROAD, WEAK ISENTROPIC UPGLIDE PERSISTS.
HOWEVER, GIVEN WEAK CONVERGENCE VALUES AND WITH NO REAL TRIGGER
FOR ANY ACCUMULATING PRECIP, WILL KEEP DRY FORECAST OVERNIGHT.
OTHERWISE, A RATHER MILD EVENING UNDER STRENGTHENING SOUTH FLOW.
WILL CONTINUE ON THE WARM SIDE OF GUIDANCE WITH LOWS IN THE LWR
60S FOR MUCH OF THE CWA, LOCALLY IN THE 50S NEAR THE COAST.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
A GENERAL CONSENSUS REMAINS AMONGST NUMERICAL MODEL DYNAMICAL AND
MOISTURE FIELDS WITH RESPECT TO THE APPROACHING FRONTAL SYSTEM.
THERE COULD BE A FEW LIGHT SHOWERS IN MOIST SSE FLOW WELL AHEAD OF
THE BOUNDARY FRIDAY MORNING. HOWEVER...NOT MUCH IS EXPECTED THROUGH
21Z DUE TO A RATHER ROBUST MID-LEVEL STABLE LAYER. MORNING STRATUS
SHOULD GIVE WAY TO A PARTLY SUNNY SKY. BREEZY CONDITIONS ARE
EXPECTED TO DEVELOP BY AFTERNOON WITH A SOUTHERLY WIND OF 15-20
MPH...WITH GUSTS TO 30 MPH POSSIBLE FROM I-95 EASTWARD TO THE COAST.
HIGH TEMPERATURES WILL RISE INTO THE UPPER 70S/LOW 80S FOR MOST OF
THE AREA...WITH THE EXCEPTION OF LOWER VALUES ALONG THE IMMEDIATE
ATLANTIC COAST OF THE EASTERN SHORE.
THE STRONGEST FORCING FOR CONVECTION ARRIVES IN THE WESTERN PORTION
OF THE AREA CLOSER TO 00Z AND REACHES THE COAST AROUND 06Z. THE
GENERAL CONSENSUS AMONGST RELATIVELY COARSER RESOLUTION MODELS IS A
NARROW ZONE OF 500-750 J/KG OF MLCAPE ALONG THE LEADING EDGE OF THE
BOUNDARY ALONG WITH 40-45KT OF DEEP LAYER (0-6KM) SHEAR.
HOWEVER...HIGH-RES DATA SUGGESTS THERE COULD INITIALLY BE 750-1000
J/KG OVER THE PIEDMONT BEFORE DIMINISHING AS THE FRONT TRANSLATED
EASTWARD. THIS COULD FAVOR A NARROW LINE OF THUNDERSTORMS ALONG THE
LEADING EDGE WITH THE POTENTIAL FOR A STRONG WIND GUSTS. SPC HAS
ISSUED A SLIGHT RISK OF SEVERE...BUT A SIGNIFICANT SEVERE OUTBREAK
IS NOT EXPECTED.
THE FRONT BECOMES MORE ANAFRONTAL AS THE NIGHT PROGRESSES WITH A
STEADY RAIN DEVELOPING. PW VALUES RISE TO 1.5-1.7IN (AROUND +2 ST
DEV) FOR MID-APRIL. THIS SHOULD RESULT IN AROUND 0.75-1.25IN OF RAIN
FOR MUCH OF THE AREA WITH THE HIGHEST AMOUNTS ACROSS SE VA/NE NC
WHERE RAIN COULD LINGER INTO SATURDAY MORNING (AND LOCALLY HIGHER
AMOUNTS WILL BE POSSIBLE DUE TO THE CONVECTIVE NATURE OF THE PRECIP
INITIALLY). STILL DO NOT SEE THIS EVENT LEADING TO ANYTHING MORE THAN
MINOR/NUISANCE FLOODING IN POOR DRAINAGE AREAS AS BULK OF THE BEST
FORCING OCCURS POST FRONTAL WITH TEMPERATURES IN THE 50S AND
60S...AS WELL AS FACT THAT APRIL FLASH FLOOD EVENTS ARE RARE IN THE
AKQ CWA. LOW TEMPERATURES SHOULD RANGE FROM THE UPPER 40S NW...TO
THE LOW 50S SE...BUT WILL REMAIN MILD AHEAD OF THE FRONT WELL INTO
FRIDAY EVENING FOR EASTERN AREAS.
A STRONG AREA OF HIGH PRESSURE BUILDS ACROSS NEW ENGLAND THROUGH THE
WEEKEND...POTENTIALLY 1040+ MB BY SUNDAY. MEANWHILE...THE A PORTION
OF THE FRONTAL BOUNDARY STALLS OFF THE SOUTHEAST COAST. THIS WILL
LEAD TO PERSISTENT ONSHORE FLOW THROUGH THE WEEKEND. HIGHS SATURDAY
SHOULD RANGE FROM THE LOW 60S E...TO MID 60S W...AND SUNDAY HIGHS
SHOULD RANGE FROM THE UPPER 50S E...TO LOW 60S W. THE SKY SHOULD BE
MOSTLY SUNNY SATURDAY AND SUNDAY FOR MUCH OF THE AREA WITH CLOUD
COVER LINGERING OVER SE PORTIONS SATURDAY AFTERNOON. LOWS SUNDAY
MORNING SHOULD BE IN THE MID 30S OVER THE PIEDMONT TO THE LOW/MID
40S OVER SE PORTIONS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
HIGH PRESSURE OVER ATLANTIC CANADA WILL SLIDE TO THE EAST. A
SOUTHERN STREAM SHORT WAVE WILL INITIATE AN INVERTED SURFACE
TROUGH OFF THE CAROLINA COAST BY MONDAY. THIS DEVELOPS INTO A LOW
PRESSURE SYSTEM TUESDAY WHICH WILL MOVE TO THE NORTHEAST. A GOOD
CHANCE FOR PCPN DEVELOPS FROM THE SOUTH MONDAY. EURO KEEPS THE PCPN
CLOSER TO THE COAST AND THE GFS SPREADS IT WELL INLAND. FOLLOWED
CLOSE TO HPC POPS WHICH BRINGS 30 PERCENT POPS MONDAY INCREASING TO
40 PERCENT ERN PORTIONS. POPS DROP OFF FROM S TO N ON TUESDAY.
MODELS ARE IN GOOD AGREEMENT WITH A COLD FRONT CROSSING THE MID
ATLANTIC STATES SOMETIME WEDNESDAY NIGHT. THE GFS LOOKS TOO FAST AND
IS ABOUT 12 HOURS QUICKER THAN THE EURO. WENT WITH HPC GUIDANCE
WHICH IS CLOSEST TO THE EURO TIMING AND HAS THE FRONT MOVING OFF THE
COAST BY EARLY THURSDAY MORNING. CHC FOR SHOWERS INCREASES FROM THE
WEST WEDNESDAY. DID NOT INCLUDE TSTMS FOR WEDNESDAY IN THE GRIDS BUT
THEY WILL NEED TO BE CONSIDERED WITH LATER ISSUANCES. HAVE 30-40
PERCENT POPS WEDNESDAY INCREASING TO 40 PERCENT POPS FOR WEDNESDAY
NIGHT AND HAVE 30-40 PERCENT FOR POST FRONTAL ACTIVITY ON THURSDAY.
IT APPEARS THAT THE AIR BEHIND THE FRONT WILL BE UNSTABLE WITH
FAIRLY COLD AIR ALOFT.
HIGH TEMPERATURES AROUND 60 MONDAY EXCEPT MID 50S NEAR THE COAST
WARM ON WEDNESDAY TO THE MID 60S NEAR THE COAST TO THE LOWER 70S
INLAND. TEMPERATURES COOL BACK TO THE 60S THURSDAY. LOW TEMPERATURES
IN THE LOW TO MID 40S MONDAY MORNING WARM TO THE 50S BY WEDNESDAY
MORNING AND COOL A BIT BY THURSDAY MORNING.
&&
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
WARM FRONT HAS MOVED NORTH OF THE AREA. GENERALLY SOUTHERLY FLOW
ACROSS THE AREA AND THIS WILL CONTINUE THROUGH THE NIGHT. CAN SEE
FOG STILL ALONG THE MD COAST AND MODELS ALL EXPAND THAT WEST WITH
TIME ACROSS SBY AFTER SUNSET. TIMED SBY TO START COMING DOWN BY
03Z AND CONTINUE TO BE IFR THROUGH 14Z. THINK ENOUGH MIXING WILL
BE OCCURRING BY THEN WITH THE SUN UP TO GET RID OF LOW CLOUDS.
BUFKIT SHOWS THESE CLOUDS ON BOTH THE RAP AND NAM MODELS TO BE
QUITE THIN. THE STATISTICAL GUIDANCE DOES NOT CLEAR IT OUT BUT IT
HAS BEEN HOLDING ON TO THE LOW CEILING TOO LONG THIS MORNING. ALSO
THE MODELS KEEP TRYING TO BRING THE OTHER TAF SITES DOWN TO IFR
AFTER MIDNIGHT BUT WITH 10 KTS OF WINDS AND ALL MODELS AGREEING
THAT THE MOISTURE IS CONFINED BELOW 925 MB THINK THE MIXING WILL
KEEP THE LOW CLOUDS AWAY OVERNIGHT. THEN ON FRIDAY WITH STRONG
COLD FRONT APPROACHING WILL HAVE BKN CU DEVELOP ACROSS THE AREA
DURING THE MORNING. THE PRECIPITATION WITH THE FRONT WILL REACH
RIC NEAR 00Z AND THERE WILL BE SOME THUNDERSTORMS ALONG THE
LEADING EDGE OF THE FRONT. MORE RAIN WILL CONTINUE FOR SEVERAL
HOURS BEHIND THE FRONT. THIS WILL BRING IFR CONDITIONS TO ALL TAF
SITES FOR FRIDAY NIGHT. CONDITIONS WILL IMPROVE RAPIDLY ON SAT
DURING THE MORNING WITH VFR CONDITIONS EXPECTED ALL AREAS BY
AFTERNOON AND CONTINUING INTO SUNDAY. COULD SEE SOME MVFR OR IFR
CONDITIONS RETURN BY MONDAY WITH BEST CHANCES NEAR THE COAST.
&&
.MARINE...
WINDS INCREASE FROM THE SE/S OVERNIGHT. HAVE SCA IN THE BAY WITH
CHANNELING EFFECT CONTRIBUTING TO THE WINDS REACHING NEAR 20 KNOTS
AT TIMES. SEAS IN THE COASTAL WATERS SLOWLY BUILD AND HAVE SCA BEGIN
IN THE NORTH BY 02Z SPREADING TO THE SOUTHERN WATERS FRIDAY MORNING.
WINDS IN THE BAY SUBSIDE BY OR SHORTLY AFTER MIDNIGHT BUT SCA
CONDITIONS RESUME FRIDAY MORNING AS WINDS INCREASE OVER ALL THE
WATERS FROM THE SOUTH. THIS OCCURRING AHEAD OF A STRONG COLD FRONT
THAT MOVES THROUGH FRIDAY NIGHT.
WINDS SHIFT TO THE NW FRIDAY NIGHT BUT WINDS ARE NOT EXPECTED TO BE
PARTICULARLY STRONG. SCA DROP OFF EARLY SATURDAY MORNING. SCA MAY
NEED TO BE EXTENDED WITH LATER ISSUANCES IN THE COASTAL WATERS FOR
SEAS OF 5 FEET OR HIGHER.
THE PRESSURE GRADIENT BETWEEN STRONG HIGH PRESSURE TO THE NORTH AND
DEVELOPING LOW PRESSURE OFF THE CAROLINA COAST WILL GENERATE AN
EXTENDED PERIOD OF NE WINDS AND SEAS OF 5 FT OR HIGHER. SCA MAY BE
NEEDED IN THE COASTAL WATERS FOR THIS BY SUNDAY MORNING AND LAST
INTO LATE MONDAY OR TUESDAY.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM FRIDAY TO MIDNIGHT EDT FRIDAY
NIGHT FOR ANZ635>638.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR ANZ630>632-
634.
SMALL CRAFT ADVISORY FROM NOON FRIDAY TO 4 AM EDT SATURDAY FOR
ANZ633.
SMALL CRAFT ADVISORY FROM 4 AM FRIDAY TO 7 AM EDT SATURDAY FOR
ANZ654.
SMALL CRAFT ADVISORY FROM 10 AM FRIDAY TO 7 AM EDT SATURDAY
FOR ANZ656-658.
SMALL CRAFT ADVISORY UNTIL 7 AM EDT SATURDAY FOR ANZ650-652.
&&
$$
SYNOPSIS...AJZ
NEAR TERM...AJZ/MAM
SHORT TERM...AJZ/LKB
LONG TERM...LSA
AVIATION...SAM
MARINE...LSA
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1118 PM CDT THU APR 18 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 249 PM CDT THU APR 18 2013
IMPRESSIVE DEFORMATION SNOW EVENT WELL UNDERWAY...WITH STRONG FGEN
NOTED IN THE H8-H5 LAYER. SEEING CONVECTIVE ELEMENTS COMING UP OUT
OF IOWA...WHICH IS AN INDICATION OF THE INSTABILITY PRESENT...WITH
SEVERAL HEAVY BANDS OF SNOW NOTED ON RADAR AS A RESULT. HAVE
GOTTEN REPORTS OF AROUND 2 INCHES PER HOUR OUT IN WRN MN THIS
AFTERNOON...AND EXPECT THESE SORTS OF RATES TO CONTINUE THROUGH
THE AFTERNOON.
THROUGH TONIGHT...FOLLOWED THE RAP FAIRLY CLOSELY FOR FORECAST
UPDATES TODAY...AS IT HAS HAD A PRETTY GOOD HANDLE ON HOW THINGS
HAVE UNFOLDED ALL DAY. AS A RESULT...BOOSTED SNOW TOTALS SOME
WITHIN THE HEART OF THE BAND FROM REDWOOD FALLS UP THROUGH ST.
CLOUD...WITH 6 INCH AMOUNTS CREEPING EAST TO BE ACROSS THE EAST
END OF THE WARNING COUNTIES NOW...WITH SNOW TOTAL AT MINNEAPOLIS
INCREASED FROM AROUND 3 INCHES TO 6 INCHES. IF THE RAP WERE TO BE
BELIEVED /WHICH BASED ON REPORTS SEEN SO FAR...DO NOT SEE WHY IT
CAN NOT BE/...THEN WE WILL LIKELY END UP WITH A BAND OF 10 TO 12
INCHES FROM GRANITE FALLS OVER TO NEW ULM AND UP TO LONG PRAIRIE
OVER TO MORA. WITH UPDATES MADE TO FORECAST TODAY...DID ADD TODD
COUNTY TO THE WARNING AND COULD HAVE VERY EASILY ADDED
STEVENS AND DOUGLAS COUNTIES OUT WEST...ALONG WITH ANOTHER ROW OF
COUNTIES TO THE EAST OF THE WARNING THAT WOULD INCLUDE THE REST OF
THE TWIN CITIES. IN FACT...AS OF THE WRITING OF THIS...THINKING
WE WILL GO AHEAD AND EXPAND THE WARNING EAST AND WEST WHEN DONE
WITH THIS AFD TO INCLUDE ALL OF THE TWIN CITIES METRO AREA.
HEAVY SNOW WILL START LETTING UP AFTER 21Z SW OF THE MN
RIVER...BETWEEN 0Z AND 3Z ALONG I-94 FROM THE TWIN CITIES UP
THROUGH ST. CLOUD...WITH HEAVY SNOW PULLING OUT OF THE NRN CWA
SHORTLY AFTER 06Z. LIGHT SNOW WILL CONTINUE THROUGH TONIGHT...WITH
LIGHT SNOW SHOWERS CONTINUING THROUGH THE DAY ACROSS WRN
WI ON FRIDAY...THOUGH MAJORITY OF ACCUMULATIONS WILL BE COMING
NOW THROUGH 12Z FRIDAY. FOR FRIDAY...ANY ADDITIONAL ACCUMULATIONS
WILL BE UNDER AN INCH.
AT 230 PM...THE RAIN/SNOW LINE WAS LOCATED NEAR AN ALBERT LEA
THROUGH RICE LAKE LINE...AND AGAIN GENERALLY FOLLOWED THE
RAP...WITH ALL SNOW FINALLY BREAKING OUT IN THE EAU CLAIRE AREA
AROUND 3Z.
AS FOR TEMPERATURES...CLOUD COVER AND NW WINDS WILL RESULT IN
FAIRLY STEADY TEMPERATURES THROUGH FRIDAY...WITH LOWS TONIGHT
FALLING BACK INTO THE UPPER 20S/LOWER 30S WHILE HIGHS ON FRIDAY
STAY MIRED IN THE 30S...OR ABOUT 20 DEGREES BELOW NORMAL.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 330 PM CDT THU APR 18 2013
SHORT DRY WINDOW WILL BE ENCOUNTERED ACROSS MUCH OF THE FA
FRIDAY NIGHT INTO MUCH OF SUNDAY AS 1025MB HIGH PRESSURE DOME
SETTLES OVER THE REGION. COPIOUS AMOUNTS OF RESIDUAL MOISTURE
FROM CURRENT SNOWSTORM COUPLED WITH RADIATIONAL
COOLING...LIGHT WINDS...SHOULD PORTEND SCT TO AREAS OF FOG
OVER MUCH OF THE CWA BETWEEN 20/06Z-20/13Z. ONLY FLY IN THE
OINTMENT WOULD BE ADVECTION OF MID TO HIGH LEVEL CLD DECK
ASSOCIATED WITH NEXT SYSTEM ENTERING FAR EASTERN MONTANA
AND WYOMING.
RAMPED UP POPS SLIGHTLY FOR SAT EVE-TUE AFTN STORM EVENT.
WEAK SFC CYCLONE ASSOCIATED WITH SAME WILL TREK FROM SE
MONTANA SUNDAY AFTN TO NE NEBRASKA BY MON/12Z. ALTHOUGH
PASSAGE OF INVERTED TROUGH AND SFC SYSTEM INTO EASTERN
WI WILL OCCUR BY LATE MONDAY NIGHT...50H TROF WILL DIG
INTO WESTERN MN BY TUE/12Z...AND THEN FINALLY MARCH THROUGH
EASTERN CWA BY EARLY WEDNESDAY MORNING. USED GFS40 FOR
ALL OF LONG TERM FORECAST CONSIDERING CURRENT EXCELLENT
HANDLING OF SNOW EVENT. BEST THETA E ADVECTION COUPLET
NOTED OVER MUCH OF CENTRAL CWA AND INTO WEST CENTRAL
WI AROUND SUN/12Z TIME PERIOD. COUPLET DEGRADES SOMEWHAT
DURING THE DAY ON SUNDAY WITH BEST THETA E ADVECTION STILL
NOTED OVER WEST CENTRAL WI. 295K ISENTROPIC ANAL INDICATES
BEST PCPN CHANCES ACROSS MUCH OF REGION LATE SAT NIGHT INTO
EARLY SUN AFTN. LUCKILY 850 TEMPS SHOULD BE WARM ENOUGH FOR
MAINLY A LIQUID PCPN EVENT THROUGH MONDAY AFTN. COULD BE A
SHORT WINDOW OF FREEZING RAIN SUN 06-12Z OVER A NARROW SWATH OF
FA 30 MILES EITHER SIDE OF A LINE FROM AXN TO ANOKA. TEMPS
ALOFT WILL PRODUCE A MAINLY LIGHT SNOW EVENT MONDAY EVENING
AND INTO TUESDAY. BEFORE THIS OCCURS HOWEVER...COULD SEE
A FEW ISOLATED THUNDERSTORMS ACROSS EXTREME SOUTHERN MN
MONDAY AFTN ASSOCIATED WITH NEAR NEGATIVE LI`S.
ANOTHER WEAK SURFACE TROF INDICATED TO SWEEP THROUGH THE
FA WED NIGHT THROUGH EARLY THU. BEST FORCING INDICATED
MAINLY OVER WEST CENTRAL WI. NOT MUCH FOR POPS AND ATMOSPHERIC
COLUMN AGAIN POINTS TO A RAIN SNOW MIX FOR THIS SHORT EVENT.
ONE GOOD NOTE FOR FORECAST CONCERNS WARMING TREND FOR AFTN
HIGHS WED-THU. LOOK FOR TEMPS RAMPING UP INTO THE UPPER 40S TO
MID 50S BOTH DAYS..WHICH IS MORE IN TUNE WITH NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1117 PM CDT THU APR 18 2013
SNOW TAPERING IN INTENSITY TO THE EAST THE NEXT HOUR OR SO. SHOULD
LIFT TO MVFR CIGS LATER TONIGHT FROM WEST TO EAST ACROSS MN
AREA...LITTLE LATER INTO WISCONSIN. LIGHT SNOW/FLURRIES INTO MID
MORNING IN THE EAST OTHERWISE MVFR CIGS BECOMING VFR INTO MN AND
BY EARLY EVENING IN WESTERN WI. NORTHWEST WINDS REMAIN STRONG AND
GUSTY AS THE SYSTEM LIFTS OFF TO THE NORTHEAST...DIMINISHING BY
EVENING MOST AREAS.
KMSP...SNOW TAPERING IN INTENSITY THROUGH THE EARLY
MORNING...WITH MAINLY FLURRIES AFTER 11Z OR SO. THIS SHOULD END IN
THE MORNING WITH CIGS LIFTING AND REMAINING MVFR INTO THE
AFTERNOON. SHOULD BREAK OUT LATE WITH GUSTY NORTHWEST WINDS DIMINISHING
AFTER 00Z SAT.
/OUTLOOK FOR KMSP/
SAT...VFR WITH MVFR AND -RA POSSIBLE LATE. WINDS SE AT 10G15KTS.
SUN...MVFR WITH IFR AND -RA POSSIBLE. WINDS S AT 10G15KTS.
MON...MVFR OR LOWER WITH -RA POSSIBLE. WINDS BCMG NNW 10G20KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 10 AM CDT FRIDAY FOR MNZ041>045-
047>070-073>076-082-083-091.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT FRIDAY FOR MNZ077-078-084-
085-092.
WI...WINTER STORM WARNING UNTIL 10 AM CDT FRIDAY FOR WIZ014.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT FRIDAY FOR WIZ015-016-
023>025.
&&
$$
SHORT TERM...MPG
LONG TERM...AJZ
AVIATION...DWE
AREA FORECAST DISCUSSION
NWS GLASGOW MT
841 PM MDT THU APR 18 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SATURDAY...
A WEAK UPPER WAVE PASSING THROUGH SOUTHERN SASKATCHEWAN HAS LED TO
SOME LIGHT SHOWER ACTIVITY AROUND THE AREA THIS EVENING. BOUNDARY
LAYER IS FAIRLY DRY AND RELATIVELY LITTLE RAIN IS MAKING IT TO
THE GROUND. SHOWERS HAVE BEEN LIGHT WITH BARELY MORE THAN A TRACE
OF RAIN. HRRR MODEL HAS PPT DECLINING TONIGHT AND MOVING EASTWARD
INTO NORTH DAKOTA. UPDATED FORECAST TO CAPTURE EXPECTED TREND WITH
PPT TONIGHT. ANY OF THESE LIGHT SHOWERS ARE EXPECTED TO TURN TO
SNOW IN THE NORTHEAST PART OF THE CWA BEFORE MIDNIGHT AND ALL
AREAS AFTER MIDNIGHT DUE TO BOUNDARY LAYER NOCTURNAL COOLING.
REST OF FORECAST APPEARS TO BE REASONABLE WITH THE NEXT CHANCE FOR
MEASURABLE PRECIPITATION COMING IN FRIDAY NIGHT AND SATURDAY
MORNING WITH THE NEXT SHORTWAVE PASSAGE...FOLLOWED BY
ANOTHER...POSSIBLY STRONGER...WAVE ON SUNDAY. MARTIN
PREVIOUS DISCUSSION...
STRONG UPPER TROUGH CONTINUES TO PUSH AWAY FROM US
WITH NORTHWEST FLOW ON THE BACKSIDE. SURFACE HIGH PRESSURE OVER
THE AREA TODAY IS PUSHING SOUTHEAST ALLOWING A WEAK DISTURBANCE TO
MOVE IN. WEAK PRECIPITATION WAS SHOWING UP OVER SASK THAT MAY
SKIRT OUR NORTHEAST CORNER THIS EVENING. BUT THE BIGGEST IMPACT
HAS BEEN THE MILDER DAY TODAY.
A STRONGER SYSTEM WILL PUSH INTO THE AREA FRIDAY NIGHT. COMPLICATED
PRECIP TYPE LOOKS TO OCCUR WITH RAIN/SNOW AND EVEN FREEZING RAIN
POSSIBILITIES. UP TO A TENTH OF AN INCH OF PRECIP LOOKS TO OCCUR
WITH THIS SYSTEM. SNOW IN THE NORTHEAST ZONES MAY ACCUMULATE BUT
LESS THAN AN INCH IS EXPECTED BY SATURDAY MORNING. NEXT WAVE TO MOVE
IN WILL OCCUR SATURDAY NIGHT.
TEMPERATURES WILL BE RELATIVELY WARM OVER THE NEXT COUPLE OF DAYS
BUT WILL STILL BE ABOUT 10 DEGREES BELOW THEIR RESPECTIVE NORMAL
LEVELS. JAMBA
.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
THE EXTENDED PERIOD BEGINS SATURDAY EVENING WITH A BROAD LONG
WAVE TROUGH STRETCHING ACROSS CONUS. AN UPPER RIDGE OCCUPIES THE
EASTERN PACIFIC AND EXTENDS NORTH INTO THE GULF OF ALASKA. THE
ARCTIC BOUNDARY WILL STILL BE MEANDERING AROUND NORTHEAST MONTANA
WHILE A SHORTWAVE TROUGH DROPS SOUTH OUT OF CANADA SENDING
MOISTURE INTO THE REGION. ALTHOUGH THE SHORTWAVE WILL SEND THE
BOUNDARY SOUTH AS A COLD FRONT...TEMPERATURE PROFILES SUGGEST
RESULTING PRECIPITATION WILL BE RAIN INITIALLY WITH A MIX OF SNOW
BEFORE SUNDAY MORNING. PRECIPITATION WILL BECOME MOSTLY SNOW NORTH OF
THE MISSOURI RIVER AND A MIX SOUTH ON SUNDAY AS CAA DROPS
TEMPERATURES ALOFT.
SUNDAY NIGHT A COLD SURFACE HIGH PUSHES SOUTH OVER NEMONT CLEARING
OUT MOST PRECIPITATION BUT DROPPING TEMPERATURES ALOFT EVEN MORE.
THE CAA WILL BE REINFORCED BY MODERATE NORTHERLY WINDS INTO SUNDAY
NIGHT.
CONDITIONS CHANGE IN THE WEST AS THE RIDGE AMPLIFIES. MODELS DRIFT
APART A BIT ON THE NEXT PHASE. THE GFS BRINGS AN EMBEDDED
SHORTWAVE DISTURBANCE SOUTH WITH THE NORTHWEST FLOW. THE EC IS
CLEAN WITH THE FLOW ALOFT AND NUDGES THE WARM FRONT INTO EASTERN
MONTANA. SO THE GFS IS WET AND THE EC IS DRY TUESDAY AND
WEDNESDAY. THE RIDGE WILL BE STRONG OVER THE WEST BUT THE LOCATION
OF THE STATIONARY BOUNDARY WILL DETERMINE IF NEMONT GOES INTO A
DRY WARM PERIOD OR THE AREA CONTINUES TO HAVE OVERRUNNING
DISTURBANCES. SCT
&&
.AVIATION...
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. AS AN UPPER
LEVEL SHORTWAVE APPROACHES THIS EVENING...A FEW ISOLATED SHOWERS
REMAIN POSSIBLE. HOWEVER...MUCH OF THE ACTIVITY HERE FORWARD WILL
BE FOCUSED IN THE SOUTHEASTERN PORTIONS OF THE AREA...NAMELY KSDY
AND KGDV. ANY SHOWER ACTIVITY WILL WIND DOWN AROUND OR BEFORE
MIDNIGHT. DURING THE DAY ON FRIDAY ANOTHER ROUND OF SHOWERS WILL
APPROACH FROM THE WEST. THESE MAY MAY REACH KGGW AROUND OR AFTER
00Z SATURDAY BUT AT THIS TIME CONFIDENCE IS LOW.
SOUTHWEST WINDS THIS EVENING OF AROUND 10 KTS WILL SWITCH AROUND
TO THE NORTHWEST LATER TONIGHT BEHIND THE SHORTWAVE. WINDS WILL
BEGIN TO TRANSITION TO BE FROM MORE OF A SOUTHEASTERLY DIRECTION
DURING THE DAY ON FRIDAY. MALIAWCO
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1204 AM CDT FRI APR 19 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 339 PM CDT THU APR 18 2013
MORNING UPPER AIR ANALYSIS INDICATES A LONGWAVE TROUGH EXTENDING
FROM SOUTH CENTRAL CANADA INTO THE PLAINS...WITH RIDGING OVER THE
EASTERN AND WESTERN CONUS. MID AND UPPER LEVEL JET ENERGY EXTENDS
SOUTH/SOUTHEAST ACROSS THE WESTERN CONUS...EAST ACROSS THE
SOUTHWESTERN CONUS AND SOUTHERN PLAINS...AND THEN NORTHEAST ACROSS
THE PLAINS AND UPPER MISSISSIPPI VALLEY. WATER VAPOR IMAGERY
INDICATES PLENTY OF MID LEVEL MOISTURE EXTENDING FROM THE SOUTHERN
PLAINS INTO THE OHIO RIVER VALLEY. A MID LEVEL DRY INTRUSION IS
EVIDENT FROM WEST TEXAS INTO EASTERN KANSAS AND PORTIONS OF MISSOURI
AND IOWA. THERE ALSO APPEARS TO BE AN AREA OF ENHANCED
VORTICITY...EMBEDDED WITHIN THE LONGWAVE TROUGH...OVER EASTERN
NEBRASKA. FINALLY...AN AXIS OF MID LEVEL DEFORMATION IS APPARENT
EXTENDING FROM THE UPPER MISSISSIPPI VALLEY...SOUTHWEST INTO THE
CENTRAL PLAINS. AT THE SURFACE AN AREA OF LOW BAROMETRIC PRESSURE IS
NOTED OVER EASTERN IOWA...WITH A COLD FRONT EXTENDING
SOUTH/SOUTHWEST ACROSS THE MISSISSIPPI VALLEY. THE LOW LEVEL WIND
FIELD ACROSS OUR AREA REMAINS FROM THE NORTHWEST AS A RESULT.
THE AFOREMENTIONED AXIS OF MID LEVEL DEFORMATION CONTINUES TO
PRESENT LIGHT SNOW TO PORTIONS OF EASTERN NEBRASKA THIS
AFTERNOON...BUT THIS ACTIVITY HAS CLEARED OUR AREA TO THE EAST FOR
THE MOST PART AND LITTLE IN THE WAY OF SNOWFALL IS BEING OBSERVED
ACROSS OUR AREA. IN ADDITION...A STRONG LOW LEVEL PRESSURE GRADIENT
CONTINUES TO PROMOTE A STRONG LOW LEVEL WIND FIELD ACROSS OUR AREA
THIS AFTERNOON. GUIDANCE FROM THE NAM...OPERATIONAL
GFS...EC...SREF-MEAN AND RAP HOWEVER ALL SUGGEST THE LOW LEVEL PRESSURE
GRADIENT WILL WEAKEN LATE THIS AFTERNOON INTO THIS EVENING...THUS
RESULTING IN DECREASING WIND SPEEDS AT THE SURFACE. GIVEN ALL
THIS...IMPROVING CONDITIONS SHOULD BE OBSERVED ACROSS THE AREA
THROUGH THE REST OF THIS AFTERNOON AND THIS EVENING AND AS A
RESULT...THE REMAINDER OF THE WINTER WEATHER ADVISORY HAS BEEN
CANCELLED.
AN OVERALL LACK IN KINEMATIC FORCING IS EXPECTED THROUGH AT LEAST
MIDDAY SATURDAY AND AS A RESULT...DRY CONDITIONS ARE EXPECTED THROUGH 18Z
SATURDAY. BY SATURDAY AFTERNOON HOWEVER...AN ~80KT MID LEVEL JET
STREAK IS EXPECTED TO MOVE ACROSS PORTIONS OF THE PLAINS AND
MISSOURI RIVER VALLEY. THE RIGHT-REAR QUADRANT OF THIS STREAK IS
EXPECTED TO SET UP SHOP OVER NORTHEASTERN PORTIONS OF OUR CWA...THUS
POTENTIALLY PROMOTING ENOUGH OF A THERMALLY-DIRECT CIRCULATION FOR
PRECIPITATION PRODUCTION. IN ADDITION TO THE SYNOPTIC-SCALE
LIFT...FORECAST PROXIMITY SOUNDINGS FROM ACROSS OUR AREA...PER THE
NAM AND OPERATIONAL GFS...SUGGEST STEEP LOW LEVEL LAPSE RATES DURING
THE AFTERNOON HOUR MAY PROMOTE UP TO 100J/KG OF POTENTIAL
INSTABILITY WITH MINIMAL CIN. ALTHOUGH LOWER TROPOSPHERIC MOISTURE
IS NOT EXPECTED TO BE ALL THAT GREAT DURING THE DAY SATURDAY...THERE
MAY BE JUST ENOUGH FORCING FOR A FEW SPRINKLES TO BE REALIZED AT THE
SURFACE. GIVEN ALL THIS...WENT AHEAD WITH SPRINKLES ACROSS ROUGHLY
THE NORTHEASTERN HALF OF OUR CWA STARTING 18Z SATURDAY.
CLEARING SKIES AND WEAK SURFACE RIDGING SHOULD PROVIDE A COLD NIGHT
ACROSS THE AREA TONIGHT...WITH LOW TEMPERATURES IN THE LOW TO MID
20S FORECAST FOR MOST LOCATIONS. PLENTY OF DIABATIC HEATING...ALONG
WITH A STRONG AND PERSISTENT DOWN-SLOPING LOW LEVEL WIND
FIELD...SHOULD PROVIDE A WARMER DAY ON SATURDAY...WITH AFTERNOON
HIGH TEMPERATURES IN THE 50S FORECAST FOR MOST LOCATIONS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 339 PM CDT THU APR 18 2013
PATTERN: OTHER THAN A BRIEF BREAK LAST WEEKEND WE/VE BEEN IN A COLD
WET PATTERN SINCE APR 9TH. WE/LL SEE A REPEAT OF THIS REPRIEVE...
IMPROVING TEMPORARILY THIS WEEKEND BEFORE THE LAST MAJOR COLD PLUNGE
IN THIS CURRENT PATTERN. THEREAFTER ENSEMBLES CONTINUE TO INDICATE A
PATTERN CHANGE WITH REORIENTATION OF THE LONG-WAVE CONFIGURATION.
THE CUT-OFF LOW CURRENTLY UNDER THE N PAC REX BLOCK WILL HEAD E...
SHOVING THE E PAC RIDGE INTO THE WRN USA.
MONTHLY TEMP THUS FAR: AS OF MIDNGT GRI IS SITTING AT AN AVERAGE
TEMP OF 43.6F. THIS IS 4.6F BELOW NORMAL. THE LAST APRIL THAT WAS
THIS COLD WAS 1983...WHICH INCLUDED ALL 30 DAYS.
ALOFT: THE SHORT-WAVE /SHRTWV/ TROF OVER THE PAC NW AT 00Z/SAT WILL
MOVE THRU SAT-SAT NGT. THIS TROF WILL BEGIN CARVING OUT THE NEXT
LGWV TROF. THE NEXT MORE POTENT SHRTWV TROF DELIVERS THE CANADIAN
COLD. THIS LAST BLAST IS FORCED BY HGT RISES APPROACHING THE W
COAST. TUE LOOKS LIKE THE COLDEST DAY.
SFC: HIGH PRES HEADS E SAT WHILE LOW PRES TRACKS ACROSS SRN CANADA.
ITS POTENT COLD FRONT WILL MOVE THRU HERE SOMETIME MON. THEN CHILLY
HIGH PRES SETTLES IN TUE-WED. A REINFORCING SHOT OF BELOW NORMAL
CHILL COULD PROVIDE A GLANCING BLOW THU...BUT TEMPS WILL STILL BE
HEADING UP. THEN FRI ITS BACK TO NORMAL /60S TO NEAR 70F/.
HAZARDS: THERE COULD BE MULTIPLE THUNDER THREATS EARLY NEXT
SUN-MON. PERIOD OF NEAR ADVISORY MATERIAL WINDS. THERE IS ALSO A
VERY LOW PROBABILITY FOR MINOR ACCUMULATING SNOW FOR PARTS OF THE
FCST AREA...ESPECIALLY IF IT COINCIDES WITH NIGHTTIME HRS MON NGT.
UPCOMING PCPN OPPORTUNITIES: MULTIPLE EVENTS OF VARYING MAGNITUDE
SAT-MON. FOR NOW LOOKS LIKE THE NEXT POTENTIALLY MODERATE PCPN EVENT
IS SLATED FOR MON NGT-TUE MRNG BUT THIS IS SUBJECT TO CHANGE.
THE DAILY DETAILS...
FRI NGT: WARM FRONT DEVELOPS AND LIFTS THRU. LOSS OF FRI AFTN`S
INSTABILITY WILL BRING AN END TO THE THREAT OF SPRINKLES.
SAT: DRY FOR MOST OF THE FCST AREA. ELEVATED MIXED LAYER /EML/
ADVECTS IN AS WINDS BACK IN THE 900-700 MB LAYER. THIS WILL STABILIZE
SFC PARCELS. LOW-LVL MSTR WILL NOT BE ENTRAINED ENUF FOR MID-LVL
INSTABILITY.
THIS TROF WILL BE MUCH MORE BROAD SUN-MON VS THE ONE MOVING THRU
ATTM. SO TRYING TO PIN DOWN ANY SENSIBLE WX AND ITS IMPACTS IS
TOUGH. FOR SURE WE KNOW THE PRIMARY FORCING MECHANISM WILL BE THE
COLD FRONTAL PASSAGE /CFP/ MON MRNG. THE GFS ENSEMBLE CLUSTERING FOR
0.5" QPF IN 24 HRS OCCURS 06Z/MON-06Z/TUE...ESSENTIALLY SUN NGT THRU
MON NGT.
MSTR RETURN WILL BE A PROBLEM WITH THIS MULTI-DAY SYSTEM. THE SYSTEM
CURRENTLY AFFECTING THE ERN USA WILL SWEEP THE HIGHEST QUALITY MSTR
FAR S INTO THE GULF. SO INSTABILITY WILL BE MODEST. PRESENT
INDICATIONS ARE THAT DWPTS OF 50F WON/T ARRIVE UNTIL MON AFTN OVER
OUR FAR SE COUNTIES. EC OFFERS SBCAPE OF 500 J/KG. SO NO SVR TSTMS
ARE EXPECTED.
MON: EARLY MRNG CFP. DAILY HIGH TEMPS MIGHT OCCUR BTWN MIDNGT AND 7
AM. STRONG CAA RESULTS IN FALLING TEMPS. HOWEVER...SUGGEST USING MON
TEMPS WITH CAUTION. THERE IS UNCERTAINTY IN TIMING OF FROPA. SOME
MID-LVL INSTABILITY MAY REMAIN ABOVE THE FRONTAL SFC AND/OR AHEAD OF
THE FRONT IF ITS PASSAGE IS DELAYED.
MON-TUE: H8 TEMPS ARE FCST 2 STANDARD DEVIATIONS BELOW NORMAL! GFS
ENSEMBLE MEAN HAS -4C H8 ISOTHERM INTO N-CNTRL KS AT 12Z/TUE.
IF TUE ENDS UP CLOUDY...WE COULD BREAK THE RECORD FOR THE COLDEST
HIGH TEMP EVER OBSERVED ON APR 23RD. THIS ISN/T IN THE BAG BECAUSE
WE/RE STILL SEE DISAGREEMENT ON WHEN THE BEST CHANCE FOR PCPN FALLS.
IF IT ENDS UP TUE AS THE 00Z EC/GEM SUGGEST...HIGH TEMPS IN THE 30S
ARE PROBABLE. NOT READY TO GO THERE YET BUT IT/S ON THE TABLE.
DON/T LOSE HEART. THE NAEFS 8-14 DAY TEMP OUTLOOK /WHICH INCLUDES
ALL THE CANADIAN-GFS ENSEMBLE MEMBERS/ INDICATES NEAR NORMAL TEMPS.
HOWEVER...AFTER THU 4/25 TEMPS MAY ACTUALLY HEAD TO THE OTHER SIDE
OF THE SCALE...AVERAGING AT OR ABOVE NORMAL TO CLOSE OUT THE
MONTH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1154 PM CDT THU APR 18 2013
AN UPPER LOW PRESSURE SYSTEM CONTINUED TO EXIT TO THE CENTRAL
PLAINS TO THE EAST...AND THE CENTER OF THE LOW WAS IN EASTERN MN
EARLY TONIGHT. SKIES WERE CLEARING IN SUBSIDENCE BEHIND THE
DEPARTING SYSTEM AND FOR THE MOST PART...KGRI SHOULD JUST SEE
SCATTERED VFR CLOUDS DURING THE OVERNIGHT HOURS. CLOUDS INCREASE
AGAIN ON FRIDAY AS CONVECTIVE TEMPS ARE REACHED AND A JET STREAK
AND SHEARED SHORTWAVE ENERGY TRANSLATE SOUTHEAST IN THE NORTHWEST
FLOW REGIME. SPRINKLES OR HIT OR MISS RAIN SHOWERS ARE POSSIBLE IN
THE AFTN BUT HAVE NOT INCLUDED IN TAF DUE TO THE ISOLATED NATURE
OF THE EXPECTED ACTIVITY. DIURNALLY DRIVEN CLOUD COVER IS EXPECTED
TO DECREASE FRIDAY EVENING WITH SUNSET. WINDS WILL BE STEADY FM THE NW
ON FRIDAY WITH GUSTS AROUND 25KTS POSSIBLE AS FORECAST SOUNDINGS
INDICATE MIXING NEAR H75. WIND SPEEDS SUBSIDE AND BECOME FAIRLY
LIGHT/VARIABLE FRIDAY EVENING IN RELAXING GRADIENT UNDER INFLUENCE
OF SUBTLE SFC RIDGING ALONG THE MISSOURI RIVER.
&&
.CLIMATE...
ISSUED AT 339 PM CDT THU APR 18 2013
GRI AND HSI WILL SET THE RECORDS FOR THE COLDEST HIGH TEMPS EVER
RECORDED FOR THIS DATE. EXPECT THE RECORD EVENT REPORTS /RER/ TO
POST AROUND OR SHORTLY AFTER 530 PM.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...BRYANT
LONG TERM...HALBLAUB
AVIATION...FAY
CLIMATE...HALBLAUB
AREA FORECAST DISCUSSION
NWS BISMARCK ND
334 AM CDT FRI APR 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT FRI APR 19 2013
THE FORECAST HIGHLIGHT FOR THE SHORT TERM PERIOD IS THE CONTINUED
CHANCES FOR LIGHT PRECIPITATION.
CURRENTLY...AN UPPER LEVEL SHORTWAVE IS DIVING SOUTHEAST OUT OF
CANADA...WHILE AN AREA OF WEAK LOW PRESSURE WAS LOCATED OVER
NORTHEASTERN MONTANA...WITH AN ASSOCIATED WARM FRONT DRAPED ACROSS
WESTERN NORTH DAKOTA AND A TRAILING COLD FRONT OVER NORTHERN
MONTANA. THE FOCUS FOR THE MID LEVEL CLOUD SHIELD AND LIGHT
PRECIPITATION THIS MORNING IS IN THE VICINITY OF THE WARM FRONT.
LATEST RADAR IMAGERY CONTINUES TO SHOW SCATTERED LIGHT RETURNS
OVER THE WEST...WHILE SURFACE OBSERVATIONS HAVE SHOWN BRIEF
PERIODS OF LIGHT SNOW. THE 00Z NAM/07Z RAP HAS THIS AREA OF LIGHT
SNOW DISSIPATING IN INTENSITY THIS MORNING...AND THUS HAVE
DECREASED POPS ACROSS THE CENTRAL PART OF THE STATE THIS MORNING.
A BRIEF LULL IN THE LIGHT PRECIPITATION WILL BE SEEN TODAY BEFORE
THE NEXT UPPER LEVEL WAVE AND ASSOCIATED SURFACE LOW PRESSURE
PROGRESSES SOUTHWARD TONIGHT. THE 00Z SUITE OF MODELS ARE IN GOOD
AGREEMENT THAT LIGHT PRECIPITATION IN THE FORM OF A LIGHT WINTRY
MIX AND LIGHT SNOW WILL MOVE INTO THE WEST BEFORE MIDNIGHT...AND
THEN SPREAD INTO THE CENTRAL AFTER MIDNIGHT.
MEANWHILE...THE CONTINUED THEME OF BELOW NORMAL TEMPERATURES WILL
CONTINUE. HIGHS WILL BE 10 TO 20 DEGREES BELOW NORMAL...AS HIGHS
WILL WARM ONLY INTO THE LOWER 30S...EXCEPT THE SOUTHWEST WHERE MID
TO UPPER 30S ARE POSSIBLE. FOR OVERNIGHT LOWS...TEMPERATURES WILL RANGE
FROM THE LOWER TEENS IN THE JAMES RIVER VALLEY TO THE UPPER 20S
FAR SOUTHWEST. A RECORD LOW TEMPERATURE FOR JAMESTOWN MAY BE IN
JEOPARDY TONIGHT...AS THE OVERNIGHT LOW IS FORECAST TO BE 12
DEGREES AND THE RECORD LOW IS 14 DEGREES SET IN 1966.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 334 AM CDT FRI APR 19 2013
THE MEDIUM RANGE MODELS CONTINUE TO PROG A WET WEEKEND FOR WESTERN
AND CENTRAL NORTH DAKOTA. A WARM FRONT PUSHING ACROSS THE REGION
WILL GENERATE CHANCE POPS SATURDAY. THE PRECIP TYPE IS EXPECTED TO
GENERALLY BE A WINTRY MIX...WITH LIGHT RAIN POSSIBLE WEST WHERE
THE WARMEST TEMPERATURES ALOFT WILL RESIDE.
AS THE WARM FRONT SHIFTS EAST SATURDAY NIGHT...A COLD FRONT WILL
ENTER WESTERN NORTH DAKOTA AFTER MIDNIGHT. THE COLD FRONT WILL
GENERATE A CHANCE OF A WINTRY MIX NORTH OF I-94 AS IT PUSHES EAST
ACROSS THE REGION SUNDAY. AREAS SOUTH OF I-94 ARE EXPECTED TO SEE
A CHANCE OF LIGHT RAIN SUNDAY. SNOW TOTALS WILL BE IN THE 1-2 INCH
RANGE NORTH...WITH MUCH LIGHTER AMOUNTS EXPECTED SOUTH AND WEST.
A DRYING/WARMING TREND IS EXPECTED MONDAY THROUGH THE END OF THE
PERIOD. HOWEVER...THE LATEST MEDIUM RANGE MODEL GUIDANCE NOW PROGS
A WEAK COLD FRONT TO PUSH THROUGH THE REGION WEDNESDAY. THIS
FEATURE IS EXPECTED TO GENERATE A SLIGHT CHANCE OF LIGHT RAIN
MIXED WITH SLEET WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 334 AM CDT FRI APR 19 2013
AN AREA OF WEAK LOW PRESSURE WILL CONTINUE TO GENERATE SCATTERED
LIGHT SNOW ACROSS WESTERN NORTH DAKOTA AT KISN/KDIK. HOWEVER...THE
EASTERN EXTENT OF THE SCATTERED LIGHT SNOW IS UNCERTAIN AS MODELS
SHOW LIGHT SNOW NOT REACHING KBIS/KMOT AND THUS HAVE DECIDED TO
ELIMINATE THE MENTION OF LIGHT SNOW AT KBIS/KMOT. RESIDUAL
MOISTURE NEAR THE SURFACE COUPLED WITH COOL AIR WILL ALLOW FOR
WIDESPREAD MVFR CONDITIONS IN LIGHT FOG AND LOWERED CEILINGS ACROSS
ALL TERMINALS EXCEPT FOR KJMS...WHERE VFR CONDITIONS WILL PREVAIL.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...LTH
LONG TERM...TM
AVIATION...LTH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1143 PM CDT THU APR 18 2013
.UPDATE...
ISSUED AT 1140 PM CDT THU APR 18 2013
NO CHANGES PLANNED FOR THIS UPDATE PERIOD. -SN CONTINUES ACROSS
THE FAR SE SO WILL MAINTAIN POPS THIS AREA. TEMPERATURES ON TRACK.
UPDATE ISSUED AT 940 PM CDT THU APR 18 2013
ONLY MINOR CHANGES FOR THIS UPDATE. -SN CONTINUES TO SHIFT EAST
WITH VERY FAR SE ONLY STATIONS REPORTING LIGHT SNOW. TRIMMED POPS
SOMEWHAT ACROSS THE FAR EAST BASED ON CURRENT RADAR TRENDS AND
SURFACE REPORTS. TEMPERATURES DROPPING ABOUT AS EXPECTED. MIXING
AND SOME ADVANCING CLOUD COVER ACROSS WESTERN DAKOTAS SHOULD LIMIT
DROP KEEPING MINIMUM TEMPERATURES PRETTY CLOSE TO WHAT WE HAVE
SEEN LAST COUPLE OF NIGHTS. NO CHANGES PLANNED AT THIS POINT.
UPDATE ISSUED AT 640 PM CDT THU APR 18 2013
PRIMARY CHANGES THIS UPDATE WILL BE TO CANCEL/EXPIRE CURRENT
ADVISORY ACROSS FAR SE FA. SNOW CONTINUES ACROSS THE FAR SE
HOWEVER WITH MINIMAL ACCUMULATIONS TODAY WITH TEMPERATURES ABOVE
FREEZING ALONG WITH IMPROVING VSBY FEEL THREAT FOR ACCUMULATING
SNOW OVER. CURRENT POPS LOOKING GOOD FOR REMAINDER OF THE EVENING
AS SYSTEM SLOWLY PUSHES EAST. NO CHANGES PLANNED TO TEMPERATURES
AT THIS POINT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 320 PM CDT THU APR 18 2013
THE PRIMARY CHALLENGE FOR THE IMMEDIATE SHORT TERM WILL BE TIMING
THE DISSIPATION OF THE SNOWFALL IN THE SOUTHEAST (WEST CENTRAL
MINNESOTA). RADAR CONTINUES TO SHOW WEAK ECHOES ROUGHLY SOUTH OF A
BAGLEY TO DETROIT LAKES TO WAHPETON LINE...WITH SOME LINGERING
LIGHT SNOW IN FAR SOUTHEASTERN RICHLAND COUNTY. HAVE USED RUC
GUIDANCE FOR QPF AND SNOWFALL CALCULATIONS IN THE REGION.
THIS EVENING...A JET STREAK THAT HAS HELPED AMPLIFY SNOWFALL OVER
SOUTHERN AND WEST CENTRAL MINNESOTA WILL MOVE OUT OF THE REGION
AND FORCING WILL WEAKEN. ISENTROPIC MODELS SHOW RISING
CONDENSATION PRESSURE DEFICITS AND NO ISENTROPIC LIFT FOR
REMAINDER OF AFTERNOON INTO THE EVENING. WHILE BOTH THE GFS AND
NAM SHOW UNSATURATED DEFICITS BY AROUND 00Z...MODELS CONTINUE TO
PRODUCE QPF THROUGH AROUND 06Z. FOR BLENDING PURPOSES WILL KEEP
LOWER POPS IN THE EXTREME SOUTHEAST THROUGH 12Z FRIDAY...BUT THINK
MOST PRECIP WILL BE OUT OF THE REGION BY MIDNIGHT.
RUC QPF VALUES SHOW A VERY TIGHT QPF GRADIENT RIGHT ALONG THE
BORDERS OF THE MINNEAPOLIS AND DULUTH COUNTY WARNING AREAS (ALONG
AND SOUTH OF A PARK RAPIDS TO PELICAN RAPIDS LINE)...WITH US ON THE
DRIER SIDE. LATEST RUC DID SURGE THE MOISTURE A BIT FURTHER
NORTH...SO WILL CONTINUE AN ADVISORY BUT IT WILL LIKELY BE IN THE
TWO TO FOUR INCH RANGE AT MOST. RECENT CALL TO GRANT COUNTY
SHERIFF INDICATES SNOW HAS PERSISTED ALL DAY BUT HAS MELTED AS IT
HIT PAVED SURFACES AND LESS THAN A HALF AN INCH ACCUMULATION ON
GRASS COVERED SURFACES. THUS PLAN TO KEEP HEADLINES AS THEY ARE...WITH A
00Z EXPIATING TIME.
WILL SEE A BRIEF PERIOD OF CLEAR SKIES IN EASTERN NORTH DAKOTA
TONIGHT...WHICH ALLOW TEMPS TO DROP INTO THE TEENS. HOWEVER MID
CLOUD WILL MOVE IN FROM SASK BY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 320 PM CDT THU APR 18 2013
THE NEXT WINTER SYSTEM WILL MOVE INTO THE REGION ON SATURDAY
AFTERNOON. A BAND OF MODERATE ISENTROPIC LIFT WILL MOVE ACROSS THE
REGION LATE SAT AND TRANSLATE ACROSS THE FORECAST AREA ON SUNDAY.
MODELS INDICATING SIGNIFICANT DIFFERENCES ON ORIENTATION OF PRECIP
AND THERMAL PROFILES...WITH THE NAM SHOWING A MUCH MORE PRONOUNCED
WARM LAYER BY ENOUGH OF A LOW LEVEL COLD LAYER FOR SOME REFREEZING
TO OCCUR. GFS IS COLDER AND SHOWS MOST PRECIP ACROSS THE SOUTH. DO
PREFER THE GFS SOLUTION AND HAVE HIGHEST POPS ACROSS SOUTHERN
ZONES. WILL GO WITH SNOW WITH SOME POSSIBLE SLEET/ICE PELLETS SAT
NIGHT AND SUN MORNING...WITH A BETTER CHANCE FOR RAIN SUN AFTN.
WILL NEED TO MONITOR UPCOMING MODELED THERMAL PROFILES TO FINE
TUNE THIS FCST PERIOD.
MODELS ARE IN DECENT AGREEMENT DEPICTING NORTHWEST FLOW ALOFT. THE
MODELS AGAIN DELAY THE UPPER RIDGE AND MUCH WARMER AIRMASS. THERE
WILL BE MINOR PRECIP CHANCES WITH THE HARD TO TIME
SHORTWAVES...BUT NOTHING MAJOR. THE CHALLENGING ASPECT WILL BE
WHEN/IF THE SNOWPACK ERODES ENOUGH THAT WE CAN START TRUSTING MOS
GUIDANCE (WHICH ASSUMES NO SNOW COVER). MIN TEMPS EARLY NEXT WEEK
ARE EXPECTED TO BE AROUND 30F...THUS REMAINING ABOVE FREEZING FOR
A LONGER DURATION DURING THE OVERNIGHT HOURS. THIS MAY BE ENOUGH
FOR AREAS WITHIN THE VALLEY TO LOSE ENOUGH SNOW COVER BY THE
MIDDLE OF NEXT WEEK ALLOWING SLIGHTLY WARMER MAX TEMPS (WITH THE
DEVILS LAKE BASIN REMAINING SNOW COVERED). THE AIRMASS WILL
UNDERGO LITTLE CHANGE THROUGH NEXT WEEK FROM WHAT IT IS NOW...AND
WHERE THERE IS SNOW COVER EXPECT MAX TEMPS INTO THE UPPER 30S OR
LOW 40S...WITH MID TO UPPER 40S WHERE SOME BLACK FIELDS START
APPEARING. NOT SURE ABOUT THE FORESTED AREAS IN MINNESOTA...AND WE
MAY BE TOO COLD FOR THIS AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1140 PM CDT THU APR 18 2013
ALL TAF SITES VFR AND ANTICIPATED TO REMAIN SO OVERNIGHT.
CONVECTIVE TEMPERATURES LOWER TOMORROW SO COULD SEE SOME VFR CIGS
DEVELOPING ACROSS THE REGION BY LATE AM.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...SPEICHER
LONG TERM...TG/SPEICHER
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
945 PM CDT THU APR 18 2013
.UPDATE...
ISSUED AT 940 PM CDT THU APR 18 2013
ONLY MINOR CHANGES FOR THIS UPDATE. -SN CONTINUES TO SHIFT EAST
WITH VERY FAR SE ONLY STATIONS REPORTING LIGHT SNOW. TRIMMED POPS
SOMEWHAT ACROSS THE FAR EAST BASED ON CURRENT RADAR TRENDS AND
SURFACE REPORTS. TEMPERATURES DROPPING ABOUT AS EXPECTED. MIXING
AND SOME ADVANCING CLOUD COVER ACROSS WESTERN DAKOTAS SHOULD LIMIT
DROP KEEPING MINIMUM TEMPERATURES PRETTY CLOSE TO WHAT WE HAVE
SEEN LAST COUPLE OF NIGHTS. NO CHANGES PLANNED AT THIS POINT.
UPDATE ISSUED AT 640 PM CDT THU APR 18 2013
PRIMARY CHANGES THIS UPDATE WILL BE TO CANCEL/EXPIRE CURRENT
ADVISORY ACROSS FAR SE FA. SNOW CONTINUES ACROSS THE FAR SE
HOWEVER WITH MINIMAL ACCUMULATIONS TODAY WITH TEMPERATURES ABOVE
FREEZING ALONG WITH IMPROVING VSBY FEEL THREAT FOR ACCUMULATING
SNOW OVER. CURRENT POPS LOOKING GOOD FOR REMAINDER OF THE EVENING
AS SYSTEM SLOWLY PUSHES EAST. NO CHANGES PLANNED TO TEMPERATURES
AT THIS POINT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 320 PM CDT THU APR 18 2013
THE PRIMARY CHALLENGE FOR THE IMMEDIATE SHORT TERM WILL BE TIMING
THE DISSIPATION OF THE SNOWFALL IN THE SOUTHEAST (WEST CENTRAL
MINNESOTA). RADAR CONTINUES TO SHOW WEAK ECHOES ROUGHLY SOUTH OF A
BAGLEY TO DETROIT LAKES TO WAHPETON LINE...WITH SOME LINGERING
LIGHT SNOW IN FAR SOUTHEASTERN RICHLAND COUNTY. HAVE USED RUC
GUIDANCE FOR QPF AND SNOWFALL CALCULATIONS IN THE REGION.
THIS EVENING...A JET STREAK THAT HAS HELPED AMPLIFY SNOWFALL OVER
SOUTHERN AND WEST CENTRAL MINNESOTA WILL MOVE OUT OF THE REGION
AND FORCING WILL WEAKEN. ISENTROPIC MODELS SHOW RISING
CONDENSATION PRESSURE DEFICITS AND NO ISENTROPIC LIFT FOR
REMAINDER OF AFTERNOON INTO THE EVENING. WHILE BOTH THE GFS AND
NAM SHOW UNSATURATED DEFICITS BY AROUND 00Z...MODELS CONTINUE TO
PRODUCE QPF THROUGH AROUND 06Z. FOR BLENDING PURPOSES WILL KEEP
LOWER POPS IN THE EXTREME SOUTHEAST THROUGH 12Z FRIDAY...BUT THINK
MOST PRECIP WILL BE OUT OF THE REGION BY MIDNIGHT.
RUC QPF VALUES SHOW A VERY TIGHT QPF GRADIENT RIGHT ALONG THE
BORDERS OF THE MINNEAPOLIS AND DULUTH COUNTY WARNING AREAS (ALONG
AND SOUTH OF A PARK RAPIDS TO PELICAN RAPIDS LINE)...WITH US ON THE
DRIER SIDE. LATEST RUC DID SURGE THE MOISTURE A BIT FURTHER
NORTH...SO WILL CONTINUE AN ADVISORY BUT IT WILL LIKELY BE IN THE
TWO TO FOUR INCH RANGE AT MOST. RECENT CALL TO GRANT COUNTY
SHERIFF INDICATES SNOW HAS PERSISTED ALL DAY BUT HAS MELTED AS IT
HIT PAVED SURFACES AND LESS THAN A HALF AN INCH ACCUMULATION ON
GRASS COVERED SURFACES. THUS PLAN TO KEEP HEADLINES AS THEY ARE...WITH A
00Z EXPIATING TIME.
WILL SEE A BRIEF PERIOD OF CLEAR SKIES IN EASTERN NORTH DAKOTA
TONIGHT...WHICH ALLOW TEMPS TO DROP INTO THE TEENS. HOWEVER MID
CLOUD WILL MOVE IN FROM SASK BY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 320 PM CDT THU APR 18 2013
THE NEXT WINTER SYSTEM WILL MOVE INTO THE REGION ON SATURDAY
AFTERNOON. A BAND OF MODERATE ISENTROPIC LIFT WILL MOVE ACROSS THE
REGION LATE SAT AND TRANSLATE ACROSS THE FORECAST AREA ON SUNDAY.
MODELS INDICATING SIGNIFICANT DIFFERENCES ON ORIENTATION OF PRECIP
AND THERMAL PROFILES...WITH THE NAM SHOWING A MUCH MORE PRONOUNCED
WARM LAYER BY ENOUGH OF A LOW LEVEL COLD LAYER FOR SOME REFREEZING
TO OCCUR. GFS IS COLDER AND SHOWS MOST PRECIP ACROSS THE SOUTH. DO
PREFER THE GFS SOLUTION AND HAVE HIGHEST POPS ACROSS SOUTHERN
ZONES. WILL GO WITH SNOW WITH SOME POSSIBLE SLEET/ICE PELLETS SAT
NIGHT AND SUN MORNING...WITH A BETTER CHANCE FOR RAIN SUN AFTN.
WILL NEED TO MONITOR UPCOMING MODELED THERMAL PROFILES TO FINE
TUNE THIS FCST PERIOD.
MODELS ARE IN DECENT AGREEMENT DEPICTING NORTHWEST FLOW ALOFT. THE
MODELS AGAIN DELAY THE UPPER RIDGE AND MUCH WARMER AIRMASS. THERE
WILL BE MINOR PRECIP CHANCES WITH THE HARD TO TIME
SHORTWAVES...BUT NOTHING MAJOR. THE CHALLENGING ASPECT WILL BE
WHEN/IF THE SNOWPACK ERODES ENOUGH THAT WE CAN START TRUSTING MOS
GUIDANCE (WHICH ASSUMES NO SNOW COVER). MIN TEMPS EARLY NEXT WEEK
ARE EXPECTED TO BE AROUND 30F...THUS REMAINING ABOVE FREEZING FOR
A LONGER DURATION DURING THE OVERNIGHT HOURS. THIS MAY BE ENOUGH
FOR AREAS WITHIN THE VALLEY TO LOSE ENOUGH SNOW COVER BY THE
MIDDLE OF NEXT WEEK ALLOWING SLIGHTLY WARMER MAX TEMPS (WITH THE
DEVILS LAKE BASIN REMAINING SNOW COVERED). THE AIRMASS WILL
UNDERGO LITTLE CHANGE THROUGH NEXT WEEK FROM WHAT IT IS NOW...AND
WHERE THERE IS SNOW COVER EXPECT MAX TEMPS INTO THE UPPER 30S OR
LOW 40S...WITH MID TO UPPER 40S WHERE SOME BLACK FIELDS START
APPEARING. NOT SURE ABOUT THE FORESTED AREAS IN MINNESOTA...AND WE
MAY BE TOO COLD FOR THIS AREA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 640 PM CDT THU APR 18 2013
VFR CONDITIONS HAVE EXPANDED ACROSS ALL TAF FORECAST POINTS AND
LIKELY TO CONTINUE OVERNIGHT. MAY STILL SEE SOME -SN NEAR BJI
HOWEVER CONDITIONS WILL CONTINUE TO SLOWLY IMPROVE AS SYSTEM
SLOWLY SHIFTS EAST.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...SPEICHER
LONG TERM...TG/SPEICHER
AVIATION...VOELKER
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1118 PM MDT THU APR 18 2013
.UPDATE...
ISSUED AT 852 PM MDT THU APR 18 2013
02Z SURFACE ANALYSIS HAD LOW OVER SOUTH CENTRAL SK WITH COLD FRONT
INTO SOUTHERN AB. WATER VAPOUR HAD COMPACT SHORTWAVE OVER SOUTH
CENTRAL SK...ON NOSE OF 90KT JET STREAK. 00Z RAP SHOWED DECENT
POTENTIAL VORTICITY MAXIMUM ASSOCIATED WITH THIS WAVE...WHICH WILL
RACE SOUTHEAST OVERNIGHT DRAGGING COLD FRONT WITH IT ALONG WITH A
NARROW BAND OF LIFT ASSOCIATED WITH 850-700MB FRONTOGENESIS AND
SYNOPTIC SCALE LIFT UNDER JET STREAK. 00Z KUNR SOUNDING PRETTY
DRY...SO A LOT OF LIFT WILL BE WASTED ON SATURATION. GIVEN
UPSTREAM RADAR RETURNS ASSOCIATED WITH WAVE WILL INTRODUCE
ISOLATED POPS THROUGH EARLY FRIDAY MORNING TO ACCOUNT. HAVE ALSO
UPPED WINDS GIVEN NARROW SHOT OF COLD AIR ADVECTION BEHIND COLD
FRONT AND 30KT 850MB WIND MAX...COULD BE A FEW BREEZY/WINDY SPOTS
TOWARD MORNING.
&&
.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 221 PM MDT THU APR 18 2013
CURRENT SURFACE ANALYSIS PLACES LOW OVER THE MIDWEST WITH HIGH
OVER THE NRN ROCKIES. UPPER LEVEL ANALYSIS PLACES DEEP TROF AXIS
PUSHING OVER THE RED RIVER VALLEY WITH CLOSED OFF LOW WORKING ITS
WAY FROM SERN SD/NWRN NEB INTO ERN IA. BREEZY CONDITIONS CONTINUE
OVER THE SODAK PLAINS IN MODEST PRESSURE GRADIENT...WITH POSSIBLY
A FEW SNOW SHOWERS OVER THE ERN CWA IN CYCLONIC FLOW IN THE WAKE
OF DEPARTING SYSTEM.
FOR TONIGHT...QUIET WEATHER IS EXPECTED AS LOW/TROF CONTINUE TO
PUSH OFF TO THE EAST WITH ANY LINGERING SHOWERS ENDING. TEMPS WILL
BE QUITE CHILLY IN THE WAKE OF DEPARTING SYSTEM.
ON FRIDAY...RIDGE TRIES TO WORKS ITS WAY INTO THE AREA WITH TEMPS
REBOUNDING. A VARIETY OF WEAK SHORT WAVES SLIDE THROUGH THE RIDGE
AND APPROACH THE AREA LATE DAY INTO THE EVENING BRINGING CHANCES
FOR RAIN OR SNOW SHOWERS.
&&
.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 221 PM MDT THU APR 18 2013
WEAK UPPER LEVEL RIDGE WILL SLIDE ACROSS THE NORTHERN PLAINS ON
SATURDAY...WITH SURFACE WARM FRONT PUSHING INTO THE EASTERN DAKOTAS.
LOW LEVEL THERMAL RIDGE IN PLACE WOULD NORMALLY PUT HIGH
TEMPERATURES INTO THE 50S/60S. HOWEVER...LINGERING SNOW COVER/MOIST
GROUND FROM MELTING WILL HOLD TEMPERATURES BACK SOME. AN UPPER LEVEL
TROF WILL THEN SET UP ACROSS THE NORTHERN PLAINS SUNDAY INTO EARLY
NEXT WEEK. BEST CHANCE OF PRECIPITATION WILL COME SUNDAY
NIGHT/MONDAY WITH ANOTHER CHANCE OF ACCUMULATING SNOW. BELOW AVERAGE
TEMPERATURES EXPECTED FOR THE FIRST HALF OF THE WEEK.
NORTH-NORTHWEST FLOW WILL PERSIST THROUGH MID WEEK WITH A SLOW
WARMING TREND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1115 PM MDT THU APR 18 2013
A FAST MOVING COLD FRONT WILL BRING A PERIOD OF GUSTY NORTHWEST
WINDS ACROSS NORTHWEST SD LATE TONIGHT/EARLY FRIDAY MORNING...SOME
LOCAL MVFR CIGS MAY OCCUR NEAR THE HIGHER TERRAIN AND NEAR
ISOLATED -SHSN. OTHERWISE...VFR CONDITIONS WILL PREVAIL WITH CIGS
FROM ABOUT 4-8KFT WITH A FEW SHOWERS FRIDAY AFTERNOON/EVENING.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...77
LONG TERM...7
AVIATION...HELGESON
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
856 PM MDT THU APR 18 2013
.UPDATE...
ISSUED AT 852 PM MDT THU APR 18 2013
02Z SURFACE ANALYSIS HAD LOW OVER SOUTH CENTRAL SK WITH COLD FRONT
INTO SOUTHERN AB. WATER VAPOUR HAD COMPACT SHORTWAVE OVER SOUTH
CENTRAL SK...ON NOSE OF 90KT JET STREAK. 00Z RAP SHOWED DECENT
POTENTIAL VORTICITY MAXIMUM ASSOCIATED WITH THIS WAVE...WHICH WILL
RACE SOUTHEAST OVERNIGHT DRAGGING COLD FRONT WITH IT ALONG WITH A
NARROW BAND OF LIFT ASSOCIATED WITH 850-700MB FRONTOGENESIS AND
SYNOPTIC SCALE LIFT UNDER JET STREAK. 00Z KUNR SOUNDING PRETTY
DRY...SO A LOT OF LIFT WILL BE WASTED ON SATURATION. GIVEN
UPSTREAM RADAR RETURNS ASSOCIATED WITH WAVE WILL INTRODUCE
ISOLATED POPS THROUGH EARLY FRIDAY MORNING TO ACCOUNT. HAVE ALSO
UPPED WINDS GIVEN NARROW SHOT OF COLD AIR ADVECTION BEHIND COLD
FRONT AND 30KT 850MB WIND MAX...COULD BE A FEW BREEZY/WINDY SPOTS
TOWARD MORNING.
&&
.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 221 PM MDT THU APR 18 2013
CURRENT SURFACE ANALYSIS PLACES LOW OVER THE MIDWEST WITH HIGH
OVER THE NRN ROCKIES. UPPER LEVEL ANALYSIS PLACES DEEP TROF AXIS
PUSHING OVER THE RED RIVER VALLEY WITH CLOSED OFF LOW WORKING ITS
WAY FROM SERN SD/NWRN NEB INTO ERN IA. BREEZY CONDITIONS CONTINUE
OVER THE SODAK PLAINS IN MODEST PRESSURE GRADIENT...WITH POSSIBLY
A FEW SNOW SHOWERS OVER THE ERN CWA IN CYCLONIC FLOW IN THE WAKE
OF DEPARTING SYSTEM.
FOR TONIGHT...QUIET WEATHER IS EXPECTED AS LOW/TROF CONTINUE TO
PUSH OFF TO THE EAST WITH ANY LINGERING SHOWERS ENDING. TEMPS WILL
BE QUITE CHILLY IN THE WAKE OF DEPARTING SYSTEM.
ON FRIDAY...RIDGE TRIES TO WORKS ITS WAY INTO THE AREA WITH TEMPS
REBOUNDING. A VARIETY OF WEAK SHORT WAVES SLIDE THROUGH THE RIDGE
AND APPROACH THE AREA LATE DAY INTO THE EVENING BRINGING CHANCES
FOR RAIN OR SNOW SHOWERS.
&&
.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 221 PM MDT THU APR 18 2013
WEAK UPPER LEVEL RIDGE WILL SLIDE ACROSS THE NORTHERN PLAINS ON
SATURDAY...WITH SURFACE WARM FRONT PUSHING INTO THE EASTERN DAKOTAS.
LOW LEVEL THERMAL RIDGE IN PLACE WOULD NORMALLY PUT HIGH
TEMPERATURES INTO THE 50S/60S. HOWEVER...LINGERING SNOW COVER/MOIST
GROUND FROM MELTING WILL HOLD TEMPERATURES BACK SOME. AN UPPER LEVEL
TROF WILL THEN SET UP ACROSS THE NORTHERN PLAINS SUNDAY INTO EARLY
NEXT WEEK. BEST CHANCE OF PRECIPITATION WILL COME SUNDAY
NIGHT/MONDAY WITH ANOTHER CHANCE OF ACCUMULATING SNOW. BELOW AVERAGE
TEMPERATURES EXPECTED FOR THE FIRST HALF OF THE WEEK.
NORTH-NORTHWEST FLOW WILL PERSIST THROUGH MID WEEK WITH A SLOW
WARMING TREND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 515 PM MDT THU APR 18 2013
AREAS MVFR CIGS WILL SPREAD INTO NORTHEAST WY OVERNIGHT AND
DISSIPATE FRIDAY MORNING. OTHERWISE...MAINLY VFR CONDITIONS
EXPECTED THROUGH THE PERIOD. SOME SHOWERS MAY DEVELOP FRIDAY
AFTERNOON MAINLY OVER THE HIGHER TERRAIN.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...77
LONG TERM...7
AVIATION...HELGESON
AREA FORECAST DISCUSSION
NWS JACKSON KY
136 AM EDT FRI APR 19 2013
.UPDATE...
ISSUED AT 1105 PM EDT THU APR 18 2013
HOURLY TEMPS...SKY...POPS AND DEWPOINTS WERE FRESHENED UP BASED ON
RECENT OBS AND MODEL TRENDS. PURE EXTRAPOLATION OF SHRA AND SOME TSRA
NOW OVER WESTERN KY AND WESTERN TN WOULD BRING IT INTO OUR AREA
A LITTLE SLOWER THAN OUR CURRENT FORECAST. WE CURRENTLY WENT WITH A
BLEND OF 18Z GFS AND 18Z AND 21Z SREF AS WELL AS THE 21Z HRRR.
OVERALL...WE EXPECT THE BAND OF PRECIP TO SPEED UP AS A SHORTWAVE
ROTATES INTO THE SOUTHEASTERN STATES. THE 23Z HRRR AND 0Z NAM ARE
ABOUT AN HOUR SLOWER...BUT THE BOTTOM LINE IS THAT IN MOST LOCATIONS
IT WILL BE RAINING DURING THE MORNING COMMUTE. NEAR THE ONSET OF THE
PRECIPITATION IS THE PERIOD WHEN LAKE WIND ADVISORY CRITERIA WINDS
ARE MOST LIKELY. OPEN TERRAIN AREAS AS WELL AS THE HIGH TERRAIN WILL
BE GUSTY ALL NIGHT. INSTABILITY IS PROGGED TO BE LIMITED AND GIVEN
EXTREMELY LIMITED LIGHTNING OPTED TO DECREASE COVERAGE OF THUNDER TO
MORE ISOLATED TO SCATTERED.
UPDATE ISSUED AT 815 PM EDT THU APR 18 2013
HOURLY TEMP...DEWPOINT AND WINDS WERE FRESHENED UP BASED ON RECENT
OBSERVED TRENDS. IT STILL APPEARS THAT OTHER THAN A POSSIBLE STRAY
SHOWER...CONVECTION WILL BE CONFINED TO RIGHT ALONG AND JUST BEHIND
THE COLD FRONT OVERNIGHT TONIGHT...AND AFTER MIDNIGHT ACROSS THE
ENTIRE REGION. ANY THUNDERSTORM OR STRONGER SHOWER WOULD BE ABLE TO
TRANSFER SOME OF THE MOMENTUM FROM STRONGER WINDS ALOFT. A STRAY GUST
EXCEEDING 40 MPH IS NOT OUT OF THE QUESTION. THE CHANCES FOR THIS ARE
PROBABLY GREATEST ALONG AND WEST OF I 75 AND ACROSS THE EASTERN
BLUEGRASS COUNTIES. LOWER DEWPOINTS AND LIMITED INSTABILITY CURRENTLY
OVER CENTRAL AND EASTERN KY AND EXPECTED TO REMAIN WILL BE A LIMITING
FACTOR TO CONVECTION AS IT MOVES EAST...BUT DRIER AIR NEAR THE SFC
COULD CONTRIBUTE TO SOME GUSTINESSS AS WELL. EVEN STILL DYNAMICS OF
THE ASSOCIATED TROUGH AND CONVERGENCE ALONG THE FRONT SHOULD LEAD TO
WIDESPREAD COVERAGE OF CONVECTION JUST AHEAD AND A FEW HOURS BEHIND
THE FRONT.
ALTHOUGH VALLEY LOCATIONS...AND PERHAPS OTHER LOCATIONS AS WELL MAY
EXPERIENCE A LULL IN THE WIND GUSTS OVER THE NEXT FEW HOURS...AS THE
FRONT APPROACHES AND AS THE PRECIP ARRIVES WINDS WILL AGAIN GUST TO
LAKE WIND ADVISORY CRITERIA...OR 35 TO 40 MPH ON AVERAGE. A FEW GUSTS
OVER 40 MPH WILL BE POSSIBLE IN ANY OF THE STRONGER CONVECTION.
OTHERWISE...HOURLY TEMP CURVES WILL BE A BIT TRICKY OVERNIGHT...ESPECIALLY
EASTERN VALLEYS THAT MAY DECOUPLE TO SOME DEGREE OVER THE NEXT 6
HOURS AND THEN AS CLOUDS AND GRADIENT INCREASE AND PRECIP ARRIVES
JUMP UP SEVERAL DEGREES BEFORE FALLING BEHIND THE FRONT.
THE POST FRONTAL AIRMASS WILL BE COLD...BUT RATHER SHALLOW. THE NAM
AND ITS HIGHER RESOLUTION AND MORE MODEL LEVELS STILL APPEARS TO HAVE
THE BEST HANDLE FOR HOURLY TEMPS LATE TONIGHT AND INTO FRI COMPARED
TO MOS OR OTHER GUIDANCE. WETBULBING SHOULD LEAD TO AN INITIAL DROP
IN TEMPS AS PRECIP ARRIVES LATE TONIGHT AND INTO FRI MORNING...AND
COLD AIR ADVECTION AND CLOUDS SHOULD LEAD TO A RATHER LIMITED TEMP
RISE ON FRI AFTERNOON.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 330 PM EDT THU APR 18 2013
18Z SFC ANALYSIS SHOWS A DEEP AREA OF LOW PRESSURE LIFTING NORTHEAST
INTO THE UPPER MIDWEST. FROM THIS...A POWERFUL COLD FRONT IS
APPROACHING THE MISSISSIPPI RIVER...KICKING OFF A LARGE LINE OF
STRONG TO SEVERE STORMS. EAST KENTUCKY IS ENJOYING A WARM AND PARTLY
SUNNY DAY OUT AHEAD OF THE FRONT...THOUGH IT IS QUITE BREEZY WITH
GUSTS PUSHING 30 MPH...AND 35 MPH WEST OF INTERSTATE 75. THIS IS
STRONG ENOUGH FOR A LAKE WIND ADVISORY AND ONE REMAINS IN EFFECT FOR
THE ENTIRE AREA...THOUGH WINDS WILL BE A NOTCH LIGHTER OVER OUR
NORTHEAST COUNTIES. THE SOUTH WINDS AND TIMES OF SUNSHINE HAVE PUSHED
READINGS INTO THE UPPER 70S AND LOW 80S THROUGH THE CWA THIS
AFTERNOON WITH ANOTHER COUPLE OF DEGREES POSSIBLE IN MOST PLACES. AT
THE SAME TIME...DEWPOINTS ARE GENERALLY IN THE MID 50S.
THE MODELS ARE IN GOOD AGREEMENT ALOFT AS THEY ALL DEPICT OUR CURRENT
OVERHEAD RIDGING YIELDING TO A DEEP TROUGH CARVING ITS WAY THROUGH
THE UPPER MIDWEST BEFORE LIFTING INTO THE WESTERN GREAT LAKES ON
FRIDAY. A LARGE ENERGY TAIL WILL SWEEP THROUGH THE OHIO VALLEY DURING
THE DAY WITH THIS TRANSITION. THIS WILL BE FOLLOWED BY GENERAL
TROUGHING THROUGHOUT THE REGION IN THE WAKE OF THE FILLING LOW WELL
OFF TO THE NORTH. GIVEN THE GOOD MODEL AGREEMENT WITH THE TIMING AND
MAGNITUDE OF THE MID LEVEL FEATURES HAVE FOLLOWED A GENERALLY MODEL
BLEND WITH A STRONG LEAN TOWARD THE HIGHER RESOLUTION NAM12.
SENSIBLE WEATHER WILL BE PRETTY STRAIGHT FORWARD THROUGH THE SHORT
TERM. A WARM EVENING WILL BE ENJOYED EAST KENTUCKY AS THE COLD FRONT
AND ITS ASSOCIATED SQUALL LINE PLODS TOWARD THE AREA. GRADIENT
WINDS WILL KEEP TEMPERATURES PROPPED UP FOR MOST SPOTS ALONG WITH AN
INCREASE IN THE CLOUDS LATER IN THE EVENING. DO NOT ANTICIPATE MUCH
IN THE WAY OF SHOWERS OR STORMS MAKING IT INTO EAST KENTUCKY BEFORE
MIDNIGHT...LIKELY SPARING ALL EVENING ACTIVITIES THROUGH THE AREA.
FOLLOWING SUNSET THE WINDS WILL LOSE A GOOD PORTION OF THEIR
GUSTINESS BUT STILL BE RATHER BREEZY DUE TO GRADIENT WINDS. THESE
SHOULD PICK UP AND BECOME GUSTY AGAIN LATER TONIGHT WITH THE PASSAGE
OF THE FRONT AND ANY SQUALL LINE ACTIVITY AHEAD OF IT. THE STORMS
WILL BE COMING THROUGH EAST KENTUCKY AT AN UNFAVORABLE TIME...LOSING
MUCH OF THE INSTABILITY WITH A PASSAGE IN THE DARK OF NIGHT. THIS IS
ALSO GOING TO BE PROGRESSIVE ENOUGH TO LIMIT THE HEAVY RAINS MAKING
FLOODING A LESSER CONCERN...DESPITE THE LOW FLASH FLOOD GUIDANCE. THE
FRONT MOVES EAST EARLY FRIDAY AND WILL BE TRAILED BY A FEW HOURS OF
SHOWERS. CAA WILL BE THE RULE WITH FALLING TEMPS EXPECTED THROUGH THE
DAY ON BRISK WEST WINDS. ALTHOUGH TEMPERATURES FRIDAY NIGHT WILL
BOTTOM OUT IN THE MID AND UPPER 30S...EXPECT ANY FROST THREAT TO BE
HINDERED BY LINGERING CLOUDS AND PROBABLY JUST ENOUGH WIND TO KEEP
THE AIR STIRRED.
FOLLOWED A BLEND OF THE MODEL DATA FOR TEMPERATURES THROUGH THE SHORT
TERM WITH A DIURNAL CURVE FROM THE NAM12 FAVORED. AS FOR POPS...HAVE
GONE HIGHER THAN ALL GUIDANCE EXPECTING MEASURABLE RAIN THROUGHOUT
ALL BUT THE FAR EASTERN PARTS OF THE AREA LATE TONIGHT...CATCHING THE
REST EARLY FRIDAY.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 345 PM EDT THU APR 18 2013
THE EXTENDED PERIOD WILL START OUT DRY AND MILD...AS AN AREA OF HIGH
PRESSURE SETTLES OVER THE AREA. TEMPERATURES ON SATURDAY WILL LIKELY
ONLY MAKE IT INTO THE MID TO UPPER 50S ACROSS THE AREA...AS A COOLER
AIR MASS IS SLOWLY SCOURED OUT OF THE AREA. TEMPERATURES ON SUNDAY
WILL BE 5 TO 8 DEGREES WARMER...AS THE AIR MASS MODIFIES AND DRIES
OUT A BIT MORE. THE BEGINNING OF THE WORK WEEK WILL FEATURE MUCH
WARMER READINGS IN THE UPPER 60S ON MONDAY...AND AROUND 70 ON
TUESDAY...AS SOUTHERLY FLOW AHEAD OF AN APPROACHING WEATHER SYSTEM
INCREASES. THE CHANCE FOR RAIN WILL ARRIVE IN THE AREA LATE TUESDAY
EVENING...AS A COLD FRONT APPROACHES FROM THE WEST. THIS BOUNDARY
WILL MOVE ACROSS THE AREA TUESDAY NIGHT THROUGH WEDNESDAY
NIGHT...BRINGING WITH IT A VERY GOOD CHANCE FOR RAIN SHOWERS AND A
FEW THUNDERSTORMS. THE INSTABILITY WITH THIS SYSTEM APPEARS A BIT
MORE LIMITED...SO THUNDERSTORM ACTIVITY WILL LIKELY NOT BE AS
WIDESPREAD AS IT WAS WITH THIS WEEKS WEATHER SYSTEMS. ONCE THE FRONT
PASSES BY...YET ANOTHER COOL AND DRY AIR MASS WILL INVADE THE
AREA...BRINGING WITH IT COOLER TEMPERATURES AND PARTLY CLOUDY SKIES
LATE WEDNESDAY NIGHT AND THURSDAY. THE WEATHER DURING THE UPCOMING
WEEKEND WILL BE CALM AND PLEASANT. CLEAR SKIES AND LIGHT WINDS COULD
LEAD TO A RIDGE VALLEY TEMPERATURE SPLIT LATE SATURDAY NIGHT INTO
EARLY SUNDAY MORNING IN OUR DEEPER AND MORE SHELTERED NORTHEASTERN
VALLEYS. THE FORECAST WAS UPDATED TO AT LEAST BEGIN HINTING AT THIS
FEATURE...PARTICULARLY WITH SUPPORT FROM THE LATEST COOPMOS DATA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 135 AM EDT FRI APR 19 2013
VFR CONDITIONS WILL PREVAIL AT ALL SITES THROUGH 10 TO 12Z BEFORE
SHRA AND SCATTERED TO NUMEROUS TSRA ALONG...AND BEHIND...A COLD
FRONT ARRIVES AT SME AND LOZ FIRST...FOLLOWED BY JKL AND FINALLY WV
BORDER. AS SHRA AND TSRA ROLL THROUGH...AT LEAST PREVAILING MVFR AND
SOME POSSIBLE BRIEF IFR OR LOWER CIGS/VIS CAN BE ANTICIPATED. GUSTY
SOUTH WINDS MAY INCREASE AS THE FRONT AND ITS LINE OF EXPECTED
STORMS NEAR. THE BREEZY SOUTH WINDS ARE EXPECTED TO SHIFT TO THE
WEST BETWEEN 10Z AND 15Z IN THE WAKE OF THE FRONT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 8 AM EDT THIS MORNING FOR KYZ044-
050>052-058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...JP
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...DUSTY
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
700 AM CDT FRI APR 19 2013
.UPDATED FOR 12Z AVIATION DISCUSSION...
ISSUED AT 643 AM CDT FRI APR 19 2013
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT FRI APR 19 2013
THE POWERFUL WINTER STORM THAT DUMPED OVER A FOOT OF SNOW IN SOME
LOCATIONS WILL EXIT THE REGION TODAY. LIGHT DEFORMATION SNOWFALL
WILL LINGER OVER THE EASTERN HALF OF THE CWA THIS MORNING...BUT THE
LARGE SCALE SUBSIDENCE ASSOCIATED WITH THE APPROACHING UPPER LEVEL
RIDGE WILL CLEAR SKIES OUT ACROSS THE WESTERN CWA. WATER VAPOR
IMAGERY DEPICTED A SHORTWAVE ON THE DOWNSTREAM AXIS OF THIS
AFOREMENTIONED UPPER LEVEL RIDGE...WITH SOME MID LEVEL CLOUDS ACROSS
THE WESTERN DAKOTAS. NUMERICAL MODELS HAVE THIS SHORTWAVE WEAKENING
WITH TIME...AND THE MID LEVEL CLOUDS DISSIPATING AS THEY DIVE
SOUTHWEST OF MINNESOTA. HOWEVER...FARTHER EAST WILL LIKELY SEE
SOME DIURNALLY DRIVEN RAIN/SNOW SHOWERS DEVELOP AS THE BOUNDARY
LAYER BECOMES DESTABILIZED THIS AFTERNOON WITH A FEW EMBEDDED
AREAS OF ENHANCED VORTICITY ROTATING AROUND THE PARENT CYCLONE
AIDING IN ASCENT. THIS IS DEPICTED WELL BY ALL 4 MEMBERS OF THE
HOPWRF ENSEMBLE. ANOTHER CONCERN IS STRONG SUSTAINED NORTHWEST
WINDS...WHICH MAY FLIRT WITH ADVISORY CRITERIA AT TIMES TODAY.
BUFR FORECAST SOUNDINGS VIA THE NAM...GFS...AND RAP ALL INDICATE
LOW TO MID 30KTS ATOP THE MIXED LAYER...WITH LAYER AVERAGED WINDS
IN THE UPPER 20S TO NEAR 30KTS. WE SHOULD BE ABLE TO MIX UP TO
850MB...BUT THE H850 WINDS DECREASE WITH TIME TODAY...SO THEREFORE
EXPECTING JUST BLUSTERY...NOT ADVISORY TYPE WINDS. HIGH PRESSURE
WILL CONTINUE TO BUILD ACROSS THE REGION TONIGHT WITH CLEARING
SKIES AND CALMING WINDS. THIS...COMBINED WITH THE FRESH
SNOWPACK...WILL SET THE STAGE FOR RECORD BREAKING LOW TEMPERATURES
BY SATURDAY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 405 AM CDT FRI APR 19 2013
SATURDAY BRINGS A BRIEF RESPITE IN PRECIPITATION AS SURFACE HIGH
PRESSURE ARRIVES. THE COOL WEATHER WILL PERSIST HOWEVER...AS
TEMPERATURES BARELY SNEAK ABOVE RECORD LOW VALUES FOR HIGHS. THIS
IS ILLUSTRATED BY THE FORECAST HIGH OF 40 AT MSP (WHERE THE RECORD
LOW HIGH TEMP FOR THE DATE IS 36) AND A FORECAST HIGH OF 37 AT
KSTC (WHERE THE RECORD LOW HIGH TEMP FOR THE DATE IS 35). BY LATE
SATURDAY AFTERNOON...A DECENT AREA OF 700-600MB OMEGA AND
INCREASING SATURATION IS EXPECTED TO SPREAD FROM WESTERN MN
EASTWARD ACROSS THE AREA. THIS SIGNALS THE TRANSITION TO AN ACTIVE
ZONAL FLOW REGIME...WITH THE SURFACE REFLECTION (IN THE FORM OF A
COLD FRONT) PROGGED TO PASS ACROSS THE REGION LATE SUNDAY INTO
MONDAY. WITH THERMAL PROFILES HOVERING AROUND 0C...WILL LIKELY SEE
A RAIN-SNOW MIX ON SATURDAY NIGHT AND SUNDAY MORNING...ALTHOUGH
ANY SNOW ACCUMULATIONS WOULD BE MINIMAL. BY SUNDAY
AFTERNOON...TEMPS WILL BE WARM ENOUGH TO YIELD RAIN. COULD ALSO
SEE SOME THUNDER IN CENTRAL/SOUTHERN MN ON SUNDAY AFTERNOON AS THE
FRONT AND LOW LEVEL TROUGH PASS...AS SUPPORTED BY SUB-ZERO GFS
BEST LI/S ATTENDANT WITH A 50-60 KT 900-850MB JET.
ON MONDAY AND TUESDAY...THE ASSOCIATED BAROCLINIC ZONE STALLS
JUST SOUTHEAST OF THE AREA...AND FOSTERS A PROLONGED PERIOD OF
LIGHT PRECIPITATION CHANCES FROM SOUTHERN MN INTO WEST CENTRAL
WI. WINTRY PRECIP WILL CONTINUE TO BE A POSSIBILITY...ESPECIALLY
DURING THE NOCTURNAL TIME FRAMES.
THURSDAY AND FRIDAY IS EXPECTED TO BRING MODERATING TEMPERATURES
AS HEIGHTS BUILD ACROSS THE REGION. BY FRIDAY...COULD SEE HIGHS
WELL INTO THE 50S...WITH 60S NOT OUT OF THE QUESTION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 643 AM CDT FRI APR 19 2013
LIGHT SNOW FROM THE DEPARTING STORM SYSTEM WILL LINGER ACROSS THE
WI/MN BORDER THIS MORNING...AND WILL SEE A FEW AFTERNOON RAIN/SNOW
SHOWERS DEVELOP AGAIN ACROSS WESTERN WISCONSIN. OTHERWISE HIGH
PRESSURE WILL BUILD ACROSS THE REGION AND ALREADY SEEING VFR
CONDITIONS ACROSS WESTERN MINNESOTA. NORTHWEST WINDS WILL PERSIST
TODAY...BUT TAPER OFF THIS EVENING WITH CLEAR SKIES EXPECTED
OVERNIGHT.
KMSP...
LOW VISBYS SHOULD IMPROVE RATHER QUICKLY THIS MORNING...AND BASED
ON CURRENT TRENDS ACROSS THE WEST SHOULD BE VFR BY LATER THIS
MORNING. COULD SEE A FEW AFTERNOON RAIN/SNOW SHOWERS...BUT
CONFIDENCE IN TIMING AND COVERAGE TOO LOW TO MENTION OTHER THAN
VCSH. SKIES WILL CLEAR OVERNIGHT WITH DECREASING WINDS.
/OUTLOOK FOR KMSP/
SAT...VFR WITH MVFR AND -RA LATE. WINDS SE AT 10G15KTS.
SUN...MVFR AND -RA WITH IFR AND TSRA POSSIBLE LATE. WINDS SSW AT
15G20KT.
MON...MVFR WITH IFR AND -RA POSSIBLE. WINDS SW EARLY...BECOMING NW
AT 10G15KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR MNZ043>045-
049>053-058>063-066>070-075-076.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR MNZ077-
078-084-085.
WI...WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR WIZ014.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR WIZ015-
016-023>025.
&&
$$
SHORT TERM...JRB
LONG TERM...LS
AVIATION...JRB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
405 AM CDT FRI APR 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT FRI APR 19 2013
THE POWERFUL WINTER STORM THAT DUMPED OVER A FOOT OF SNOW IN SOME
LOCATIONS WILL EXIT THE REGION TODAY. LIGHT DEFORMATION SNOWFALL
WILL LINGER OVER THE EASTERN HALF OF THE CWA THIS MORNING...BUT THE
LARGE SCALE SUBSIDENCE ASSOCIATED WITH THE APPROACHING UPPER LEVEL
RIDGE WILL CLEAR SKIES OUT ACROSS THE WESTERN CWA. WATER VAPOR
IMAGERY DEPICTED A SHORTWAVE ON THE DOWNSTREAM AXIS OF THIS
AFOREMENTIONED UPPER LEVEL RIDGE...WITH SOME MID LEVEL CLOUDS ACROSS
THE WESTERN DAKOTAS. NUMERICAL MODELS HAVE THIS SHORTWAVE WEAKENING
WITH TIME...AND THE MID LEVEL CLOUDS DISSIPATING AS THEY DIVE
SOUTHWEST OF MINNESOTA. HOWEVER...FARTHER EAST WILL LIKELY SEE
SOME DIURNALLY DRIVEN RAIN/SNOW SHOWERS DEVELOP AS THE BOUNDARY
LAYER BECOMES DESTABILIZED THIS AFTERNOON WITH A FEW EMBEDDED
AREAS OF ENHANCED VORTICITY ROTATING AROUND THE PARENT CYCLONE
AIDING IN ASCENT. THIS IS DEPICTED WELL BY ALL 4 MEMBERS OF THE
HOPWRF ENSEMBLE. ANOTHER CONCERN IS STRONG SUSTAINED NORTHWEST
WINDS...WHICH MAY FLIRT WITH ADVISORY CRITERIA AT TIMES TODAY.
BUFR FORECAST SOUNDINGS VIA THE NAM...GFS...AND RAP ALL INDICATE
LOW TO MID 30KTS ATOP THE MIXED LAYER...WITH LAYER AVERAGED WINDS
IN THE UPPER 20S TO NEAR 30KTS. WE SHOULD BE ABLE TO MIX UP TO
850MB...BUT THE H850 WINDS DECREASE WITH TIME TODAY...SO THEREFORE
EXPECTING JUST BLUSTERY...NOT ADVISORY TYPE WINDS. HIGH PRESSURE
WILL CONTINUE TO BUILD ACROSS THE REGION TONIGHT WITH CLEARING
SKIES AND CALMING WINDS. THIS...COMBINED WITH THE FRESH
SNOWPACK...WILL SET THE STAGE FOR RECORD BREAKING LOW TEMPERATURES
BY SATURDAY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 405 AM CDT FRI APR 19 2013
SATURDAY BRINGS A BRIEF RESPITE IN PRECIPITATION AS SURFACE HIGH
PRESSURE ARRIVES. THE COOL WEATHER WILL PERSIST HOWEVER...AS
TEMPERATURES BARELY SNEAK ABOVE RECORD LOW VALUES FOR HIGHS. THIS
IS ILLUSTRATED BY THE FORECAST HIGH OF 40 AT MSP (WHERE THE RECORD
LOW HIGH TEMP FOR THE DATE IS 36) AND A FORECAST HIGH OF 37 AT
KSTC (WHERE THE RECORD LOW HIGH TEMP FOR THE DATE IS 35). BY LATE
SATURDAY AFTERNOON...A DECENT AREA OF 700-600MB OMEGA AND
INCREASING SATURATION IS EXPECTED TO SPREAD FROM WESTERN MN
EASTWARD ACROSS THE AREA. THIS SIGNALS THE TRANSITION TO AN ACTIVE
ZONAL FLOW REGIME...WITH THE SURFACE REFLECTION (IN THE FORM OF A
COLD FRONT) PROGGED TO PASS ACROSS THE REGION LATE SUNDAY INTO
MONDAY. WITH THERMAL PROFILES HOVERING AROUND 0C...WILL LIKELY SEE
A RAIN-SNOW MIX ON SATURDAY NIGHT AND SUNDAY MORNING...ALTHOUGH
ANY SNOW ACCUMULATIONS WOULD BE MINIMAL. BY SUNDAY
AFTERNOON...TEMPS WILL BE WARM ENOUGH TO YIELD RAIN. COULD ALSO
SEE SOME THUNDER IN CENTRAL/SOUTHERN MN ON SUNDAY AFTERNOON AS THE
FRONT AND LOW LEVEL TROUGH PASS...AS SUPPORTED BY SUB-ZERO GFS
BEST LI/S ATTENDANT WITH A 50-60 KT 900-850MB JET.
ON MONDAY AND TUESDAY...THE ASSOCIATED BAROCLINIC ZONE STALLS
JUST SOUTHEAST OF THE AREA...AND FOSTERS A PROLONGED PERIOD OF
LIGHT PRECIPITATION CHANCES FROM SOUTHERN MN INTO WEST CENTRAL
WI. WINTRY PRECIP WILL CONTINUE TO BE A POSSIBILITY...ESPECIALLY
DURING THE NOCTURNAL TIME FRAMES.
THURSDAY AND FRIDAY IS EXPECTED TO BRING MODERATING TEMPERATURES
AS HEIGHTS BUILD ACROSS THE REGION. BY FRIDAY...COULD SEE HIGHS
WELL INTO THE 50S...WITH 60S NOT OUT OF THE QUESTION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1117 PM CDT THU APR 18 2013
SNOW TAPERING IN INTENSITY TO THE EAST THE NEXT HOUR OR SO. SHOULD
LIFT TO MVFR CIGS LATER TONIGHT FROM WEST TO EAST ACROSS MN
AREA...LITTLE LATER INTO WISCONSIN. LIGHT SNOW/FLURRIES INTO MID
MORNING IN THE EAST OTHERWISE MVFR CIGS BECOMING VFR INTO MN AND
BY EARLY EVENING IN WESTERN WI. NORTHWEST WINDS REMAIN STRONG AND
GUSTY AS THE SYSTEM LIFTS OFF TO THE NORTHEAST...DIMINISHING BY
EVENING MOST AREAS.
KMSP...SNOW TAPERING IN INTENSITY THROUGH THE EARLY
MORNING...WITH MAINLY FLURRIES AFTER 11Z OR SO. THIS SHOULD END IN
THE MORNING WITH CIGS LIFTING AND REMAINING MVFR INTO THE
AFTERNOON. SHOULD BREAK OUT LATE WITH GUSTY NORTHWEST WINDS DIMINISHING
AFTER 00Z SAT.
/OUTLOOK FOR KMSP/
SAT...VFR WITH MVFR AND -RA POSSIBLE LATE. WINDS SE AT 10G15KTS.
SUN...MVFR WITH IFR AND -RA POSSIBLE. WINDS S AT 10G15KTS.
MON...MVFR OR LOWER WITH -RA POSSIBLE. WINDS BCMG NNW 10G20KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR MNZ041>045-
047>070-073>076-082-083-091.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR MNZ077-
078-084-085-092.
WI...WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR WIZ014.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR WIZ015-
016-023>025.
&&
$$
SHORT TERM...JRB
LONG TERM...LS
AVIATION...DWE
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1033 AM EDT FRI APR 19 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL MOVE ACROSS CENTRAL NORTH CAROLINA THIS
AFTERNOON AND EVENING...BRINGING WITH IT HEAVY RAIN AND THE CHANCE
FOR SEVERE THUNDERSTORMS. BEHIND THE FRONT...COOLER AND DRIER
CONDITIONS WILL MOVE IN FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 1030 AM FRIDAY...
OBSERVATIONS SHOW THE INGREDIENTS COMING TOGETHER FOR A POTENTIALLY
SEVERE THUNDERSTORM EVENT ACROSS CENTRAL NORTH CAROLINA LATER THIS
AFTERNOON AND INTO THE EVENING. AIDED BY THE DEVELOPMENT OF A 50
KNOT LOW LEVEL GET AT 850 THROUGH 700 MB...MOISTURE HAS BEGUN TO
INCREASE ACROSS THE AREA AND TEMPERATURES RISING INTO THE LOW TO MID
70S HAS BEGUN TO ERODE ANY LEFTOVER CIN FROM THE OVERNIGHT HOURS AND
INSTABILITY IS BEGINNING TO INCREASE. RADAR TRENDS SHOW SOME
CONVECTIVE DEVELOPMENT ALONG THE COASTAL AREAS AS WELL AS SOME
SMALLER SHOWERS BREAKING OUT BACK ACROSS THE WESTERN PIEDMONT IN
ADVANCE OF THE MAIN LINE OF SHOWERS AND THUNDERSTORMS WHICH IS
CURRENTLY TREKKING THROUGH THE MOUNTAINS OF EASTERN TENNESSEE.
COMPARED TO HIGH RESOLUTION MODELS IT APPEARS THE ACTUAL STORM
SYSTEM MAY BE AN HOUR OR TWO AHEAD OF SCHEDULE. FOR THE TIMING
ACROSS THE CWA WILL MOVE UP THE TIME FRAME TO NEAR 21Z (5 PM) IN THE
TRIAD...00Z (8 PM) FOR THE TRIANGLE AND 03Z (11 PM) FOR THE I-95
CORRIDOR. DAMAGING WINDS AND HEAVY RAIN ARE STILL THE PRIMARY
THREATS ASSOCIATED WITH THIS SYSTEM ALTHOUGH SMALL HAIL AND ISOLATED
TORNADOES WILL STILL BE POSSIBLE...ESPECIALLY IN THE SOUTH AND EAST
WHERE A LOOK AT RAP SOUNDINGS THROUGH BUFKIT SHOW INCREASED 0-1 KM
HELICITY. THIS WOULD ESPECIALLY BE A CONCERN IN ANY DISCREET CELLS
THAT DEVELOP OUT AHEAD OF THE LINE OF THUNDERSTORMS. GOES VISIBLE
SATELLITE IMAGERY SHOWS SOME BREAKS IN THE CLOUD COVER OVER SOUTH
CAROLINA BEGINNING TO ADVANCE NORTHWARD INDICATING THAT A GREATER
DIFFERENTIAL HEATING BOUNDARY MAY SET UP OVER THE CWA WITH HIGHER
MAX TEMPS IN THE SOUTH AND EAST (MIDDLE 80S) AS COMPARED TO THE
TRIAD (UPPER 70S). THIS BOUNDARY COULD BECOME A FOCUS FOR CONVECTION
LATER ON THIS EVENING. ONCE THE FRONT CLEARS TO THE EAST EXPECT
LINGERING ANAFRONTAL RAIN TO CONTINUE FOR SEVERAL HOURS. -ELLIS
OVERNIGHT LOWS ON FRIDAY NIGHT WILL BE DEPENDENT ON THE TIMING OF
THE EXITING PRECIP AND COMMENCEMENT OF COLD AIR ADVECTION. AT THIS
TIME...IT APPEARS PRECIP SHOULD CLEAR OUT OF AT LEAST THE WESTERN
PORTIONS OF THE FORECAST AREA BEFORE DAYBREAK AND THEREFORE AM
EXPECTING TEMPS TO RANGE FROM THE UPPER 40S/LOWER 50S ACROSS THE
WEST TO MID/UPPER 50S FURTHER EAST. CONDITIONS WILL IMPROVE
THROUGHOUT THE DAY ON SATURDAY AND WITH COLD AIR ADVECTION
PERSISTING...HIGHS SHOULD GENERALLY BE IN THE MID/UPPER 60S.-KRR
&&
.SHORT TERM /SATURDAY NIGHT AND SUNDAY/...
AS OF 250 AM FRIDAY...
CANADIAN SURFACE HIGH OVER THE UPPER GREAT LAKES WILL STRENGTHEN TO
+1040MB AS IT BUILDS EASTWARD...REACHING THE NEW ENGLAND COAST BY
SUNDAY NIGHT. THIS WILL KEEP IT SEASONABLY COOL AND DRY TO CLOSE THE
WEEKEND WITH LOW-LEVEL THICKNESSES A GOOD 20 TO 25 METERS BELOW
NORMAL WHICH SHOULD TRANSLATE INTO TEMPERATURES A GOOD 10 DEGREES
BELOW NORMAL. EARLY MORNING RISERS WILL NEED A JACKET SUNDAY MORNING
WITH MIN TEMPS 40 TO 45. HIGHS 60 TO 65 WITH BREEZY NELY WINDS
DEVELOPING BY THE AFTERNOON WITH COMPRESSION OF PRESSURE GRADIENT AS
OFFSHORE FRONTAL ZONE BEGINS TO SHARPEN UP.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 250 AM FRIDAY...
...BELOW NORMAL TEMPERATURES NEXT WEEK...
A WEAK MOISTURE DEPRIVED UPPER LEVEL DISTURBANCE IN ADVANCE OF A
MORE SIGNIFICANT NORTHERN STREAM TROUGH WILL QUIETLY MOVE
EASTWARD ACROSS SOUTHERN PLAINS/LOWER MS VALLEY SATURDAY NIGHT
THROUGH SUNDAY. BUT AS THE UPPER DISTURBANCE CROSSES THE SOUTHERN
APPALACHIANS AND MOVES OVER THE CAROLINAS SUNDAY NIGHT/MONDAY...WEAK
CYCLOGENESIS ALONG AN OLD BAROCLINIC FRONTAL ZONE SITTING OFF THE
SOUTHEAST COAST WILL BRING RENEWED VIGOR TO THE UPPER WAVE. RECENT
MODEL RUNS HAVE SHIFTED SLIGHTLY EASTWARD...KEEPING THE BULK OF THE
OVERRUNNING PRECIP ALONG THE IMMEDIATE COAST. WILL CONTINUE TO
MONITOR THIS SYSTEM...ESPECIALLY FOR ANY WESTWARD/INLAND TREND AS
ANY PRECIP FALLING INTO THE WEDGE OF STRONG HIGH PRESSURE EXTENDING
DOWN THE EASTERN SLOPES OF THE APPALACHIANS WILL RESULT IN A STRONG
CAD EVENT FOR MONDAY. FOR NOW WILL GO WITH JUST SLIGHT CHANCE POPS
IN THE EAST...KEEPING THE WESTERN TWO-THIRDS OF THE FORECAST AREA
DRY. TEMPERATURES MONDAY WILL NOT BE MUCH DIFFERENT THAN FROM SUNDAY
WITH LOWS MONDAY MORNING IN THE LOWER TO MID 40S. HIGHS IN THE
LOWER 60S...BUT COULD END UP SIGNIFICANTLY COOLER IF MODELS TREND
WETTER WITH FUTURE RUNS.
THE AFOREMENTIONED NORTHERN STREAM TROUGH AND ATTENDANT SFC COLD
FRONT WILL APPROACH THE AREA FROM THE WEST WEDNESDAY NIGHT/THURSDAY
BRINGING WIDESPREAD SHOWERS TO THE AREA WITH PERHAPS A CHANCE OF
THUNDER. TEMPERATURES WILL REBOUND BACK INTO THE 70S AHEAD OF THE
FRONT ON WEDNESDAY...AND THEN FALLING BACK TO BELOW NORMAL BEHIND
THE FRONTAL PASSAGE TO CLOSE THE WEEK.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 720 AM FRIDAY...
24-HR TAF PERIOD:
WIDESPREAD MVFR CONDITIONS IN ASSOCIATION WITH STRONG S/SE LOW-LEVEL
MOISTURE ADVECTION IN ADVANCE OF THE STRONG COLD FRONT OVER THE TN
VALLEY WILL LIFT SLOWLY BETWEEN 15 TO 18Z. THEN BETWEEN 20Z FRI TO
06Z SAT...MVFR/IFR CONDITIONS ASSOCIATED WITH A LINE OF SHOWERS AND
THUNDERSTORMS WILL MOVE WEST TO EAST ACROSS THE AREA. ISOLD SEVERE
THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WIND GUSTS AOA 50 KT
WILL BE POSSIBLE WITH THE LINE OF STORMS. VFR CONDITIONS WILL THEN
SPREAD WEST TO EAST BETWEEN 06 TO 12Z SATURDAY MORNING AS DRIER AIR
FILTERS INTO THE AREA IN THE WAKE OF THE COLD FRONT PASSAGE.
A STEADY SOUTHERLY 10 KT WIND IS EXPECTED OVERNIGHT...BECOMING S/SW
AND INCREASING TO 15-20 KT WITH GUSTS UP TO 30 KT FRIDAY AFTERNOON
AS THE COLD FRONT PROGRESSES INTO WESTERN NC AND THE MSLP GRADIENT
TIGHTENS. WINDS WILL SHIFT TO THE NORTHWEST AT 10-15 KT WITH GUSTS
UP TO 20-25 KT IN THE WAKE OF THE COLD FRONTAL PASSAGE SATURDAY
MORNING.
LOOKING AHEAD:
VFR CONDITIONS ARE EXPECTED THROUGH SUNDAY AS STRONG HIGH PRESSURE
EXTENDS SOUTHWARD FROM NEW ENGLAND INTO THE CAROLINAS. BREEZY NE/ENE
WINDS WILL DEVELOP SUNDAY AFTERNOON AND ADVECT ATLANTIC MOISTURE
INTO THE REGION...RESULTING IN WIDESPREAD IFR/MVFR CEILINGS SUNDAY
NIGHT AND INTO MONDAY...ESPECIALLY AT THE EASTERN TERMINALS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...ELLIS/KRR
SHORT TERM...CBL
LONG TERM...CBL
AVIATION...CBL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
701 AM CDT FRI APR 19 2013
.UPDATE...
ISSUED AT 701 AM CDT FRI APR 19 2013
HIGH PRESSURE BUILDING INTO THE REGION HAS SCOURED OUT MUCH OF THE
LOW-LEVEL MOISTURE ACROSS CENTRAL NORTH DAKOTA. AS A
RESULT...DECREASED THE FIRST PERIOD SKY COVER ACROSS THE
AFOREMENTIONED REGION.
A 75+ KT 500MB JET STREAK DIVING SOUTH OVER WESTERN NORTH DAKOTA
HAS GENERATED VERY NARROW SNOW BANDS WEST THIS MORNING. AS A
RESULT...SHIFTED ISOLATED POPS A LITTLE FARTHER WEST BASED ON
CURRENT OBS/TRENDS. THIS JET STREAK SHOULD BE OVER SOUTH DAKOTA BY
MID TO LATE MORNING TAKING ANY PRECIP CHANCES WITH IT.
THE REMAINED GRIDDED WEATHER ELEMENTS ARE IN GOOD SHAPE. THE
UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT FRI APR 19 2013
THE FORECAST HIGHLIGHT FOR THE SHORT TERM PERIOD IS THE CONTINUED
CHANCES FOR LIGHT PRECIPITATION.
CURRENTLY...AN UPPER LEVEL SHORTWAVE IS DIVING SOUTHEAST OUT OF
CANADA...WHILE AN AREA OF WEAK LOW PRESSURE WAS LOCATED OVER
NORTHEASTERN MONTANA...WITH AN ASSOCIATED WARM FRONT DRAPED ACROSS
WESTERN NORTH DAKOTA AND A TRAILING COLD FRONT OVER NORTHERN
MONTANA. THE FOCUS FOR THE MID LEVEL CLOUD SHIELD AND LIGHT
PRECIPITATION THIS MORNING IS IN THE VICINITY OF THE WARM FRONT.
LATEST RADAR IMAGERY CONTINUES TO SHOW SCATTERED LIGHT RETURNS
OVER THE WEST...WHILE SURFACE OBSERVATIONS HAVE SHOWN BRIEF
PERIODS OF LIGHT SNOW. THE 00Z NAM/07Z RAP HAS THIS AREA OF LIGHT
SNOW DISSIPATING IN INTENSITY THIS MORNING...AND THUS HAVE
DECREASED POPS ACROSS THE CENTRAL PART OF THE STATE THIS MORNING.
A BRIEF LULL IN THE LIGHT PRECIPITATION WILL BE SEEN TODAY BEFORE
THE NEXT UPPER LEVEL WAVE AND ASSOCIATED SURFACE LOW PRESSURE
PROGRESSES SOUTHWARD TONIGHT. THE 00Z SUITE OF MODELS ARE IN GOOD
AGREEMENT THAT LIGHT PRECIPITATION IN THE FORM OF A LIGHT WINTRY
MIX AND LIGHT SNOW WILL MOVE INTO THE WEST BEFORE MIDNIGHT...AND
THEN SPREAD INTO THE CENTRAL AFTER MIDNIGHT.
MEANWHILE...THE CONTINUED THEME OF BELOW NORMAL TEMPERATURES WILL
CONTINUE. HIGHS WILL BE 10 TO 20 DEGREES BELOW NORMAL...AS HIGHS
WILL WARM ONLY INTO THE LOWER 30S...EXCEPT THE SOUTHWEST WHERE MID
TO UPPER 30S ARE POSSIBLE. FOR OVERNIGHT LOWS...TEMPERATURES WILL RANGE
FROM THE LOWER TEENS IN THE JAMES RIVER VALLEY TO THE UPPER 20S
FAR SOUTHWEST. A RECORD LOW TEMPERATURE FOR JAMESTOWN MAY BE IN
JEOPARDY TONIGHT...AS THE OVERNIGHT LOW IS FORECAST TO BE 12
DEGREES AND THE RECORD LOW IS 14 DEGREES SET IN 1966.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 334 AM CDT FRI APR 19 2013
THE MEDIUM RANGE MODELS CONTINUE TO PROG A WET WEEKEND FOR WESTERN
AND CENTRAL NORTH DAKOTA. A WARM FRONT PUSHING ACROSS THE REGION
WILL GENERATE CHANCE POPS SATURDAY. THE PRECIP TYPE IS EXPECTED TO
GENERALLY BE A WINTRY MIX...WITH LIGHT RAIN POSSIBLE WEST WHERE
THE WARMEST TEMPERATURES ALOFT WILL RESIDE.
AS THE WARM FRONT SHIFTS EAST SATURDAY NIGHT...A COLD FRONT WILL
ENTER WESTERN NORTH DAKOTA AFTER MIDNIGHT. THE COLD FRONT WILL
GENERATE A CHANCE OF A WINTRY MIX NORTH OF I-94 AS IT PUSHES EAST
ACROSS THE REGION SUNDAY. AREAS SOUTH OF I-94 ARE EXPECTED TO SEE
A CHANCE OF LIGHT RAIN SUNDAY. SNOW TOTALS WILL BE IN THE 1-2 INCH
RANGE NORTH...WITH MUCH LIGHTER AMOUNTS EXPECTED SOUTH AND WEST.
A DRYING/WARMING TREND IS EXPECTED MONDAY THROUGH THE END OF THE
PERIOD. HOWEVER...THE LATEST MEDIUM RANGE MODEL GUIDANCE NOW PROGS
A WEAK COLD FRONT TO PUSH THROUGH THE REGION WEDNESDAY. THIS
FEATURE IS EXPECTED TO GENERATE A SLIGHT CHANCE OF LIGHT RAIN
MIXED WITH SLEET WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 701 AM CDT FRI APR 19 2013
AN AREA OF WEAK LOW PRESSURE WILL CONTINUE TO GENERATE SCATTERED
LIGHT SNOW ACROSS WESTERN NORTH DAKOTA AT KISN/KDIK. HOWEVER...THE
EASTERN EXTENT OF THE SCATTERED LIGHT SNOW IS UNCERTAIN AS MODELS
SHOW LIGHT SNOW NOT REACHING KBIS/KMOT AND THUS HAVE DECIDED TO
ELIMINATE THE MENTION OF LIGHT SNOW AT KBIS/KMOT. RESIDUAL
MOISTURE NEAR THE SURFACE COUPLED WITH COOL AIR WILL ALLOW FOR
WIDESPREAD MVFR CONDITIONS IN LIGHT FOG AND LOWERED CEILINGS ACROSS
ALL TERMINALS EXCEPT FOR KJMS...WHERE VFR CONDITIONS WILL PREVAIL.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TM
SHORT TERM...LTH
LONG TERM...TM
AVIATION...LTH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
644 AM CDT FRI APR 19 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 255 PM CDT THU APR 18 2013
LATEST WATER VAPOR SATELLITE IMAGERY PLACED A SHORTWAVE TROUGH OVER
THE REGION...WITH TRENDS DRIVING IT EAST/NORTHEAST. GOOD MID LEVEL
DRY PUNCH ALSO INDICATED...WHICH SHOWS UP IN THE RAP BUFKIT
SOUNDINGS. THIS HAS RESULTED IN THE LOSS OF ICE IN SOME OF THE
CLOUD...AND MOSTLY AREAS OF DRIZZLE AHEAD OF TROUGH/UPPER LEVEL LOW.
DEPENDING ON SFC TEMPS...THERE COULD BE SOME PATCHY FREEZING
DRIZZLE. WEST-EAST RUNNING X-SECTION AND BUFKIT SOUNDINGS DO POINT
TO A RETURN OF THE ICE QUICKLY EARLY THIS MORNING...AND THUS EITHER
SNOW OR RAIN. GIVEN THE MOVEMENT OF THE SYSTEM...THE BETTER CHANCES
FOR ACCUMULATING PCPN WILL BE ACROSS THE NORTH...AND MOSTLY THIS
MORNING.
FOR THE AFTERNOON...RAP SOUNDINGS BUILD SOME SHALLOW NEAR SFC
INSTABILITY...UP TO AROUND 800 MB. 1000-850 MB LAPSE RATES ARE
AROUND 8.5 C/KM. ENOUGH LOW LEVEL SATURATION THAT THIS INSTABILITY
SHOULD RESULT IN SCT/WIDESPREAD SHOWERS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 255 AM CDT FRI APR 19 2013
RELATIVELY STRONG 925-850 MB WARM AIR ADVECTION AND ISENTROPIC
UPGLIDE ON THE 280-290 K SFCS SLATED TO MOVE ACROSS THE FORECAST
AREA BETWEEN 06Z SUN - 00Z MON. THE LOW LEVEL THERMODYNAMIC FORCING
IS AHEAD OF A SHORTWAVE TROUGH SLATED TO DROP SOUTHEAST OVER THE
NORTHERN PLAINS SUN AFTERNOON...AND BE A PLAYER IN PCPN CHANCES FOR
THE REGION FOR THE EARLY PART OF THE NEW WORK WEEK. A FEW PIECES OF
UPPER LEVEL ENERGY AHEAD OF THE TROUGH...WHICH WOULD ADD TO THE
FORCING MIX FOR SUN. WEST-EAST RUNNING X-SECTION POINTS TO
INCREASING SATURATION BY 06Z SUN...DEEP ENOUGH AND COLD ENOUGH FOR
THERE TO BE ICE IN THE CLOUD. PRETTY GOOD CHANCE FOR SOME PCPN WITH
THE LOW LEVEL FORCING...WITH A SNOW/RAIN MIX INITIALLY CHANGING OVER
TO RAIN DURING THE DAY SUNDAY. A HINT OF INSTABILTY IN NAM BUFKIT
SOUNDINGS...BUT NOT MUCH/IF ANY IN THE GFS. WILL KEEP THUNDER
MENTION OUT OF THE FORECAST FOR NOW.
THE TROUGH/S SFC LOW/COLD FRONT SWING IN SUN NIGHT. GFS AND NAM AT
ODDS WITH THE TIMING...WITH THE 19.00Z NAM BRINGING THE FRONT TO THE
MISSISSIPPI RIVER AROUND 03Z MON...WITH THE GFS HOLDING OFF UNTIL
CLOSER TO 12Z MON. THE EC AND GEM ARE CLOSER TO THE GFS. WILL LIKELY
LEAN THIS WAY FOR TIMING. WITH SOME LOW LEVEL MOISTURE RETURN AHEAD
OF THE FRONT...IT WILL SERVE AS ANOTHER FOCUS FOR PCPN GENERATION.
THE GFS AND EC SWING BITS OF UPPER LEVEL ENERGY ACROSS THE REGION
SUN NIGHT-TUE NIGHT...AHEAD OF AN UPPER LEVEL TROUGH WHICH MOVES
OVER THE UPPER MISSISSIPPI RIVER VALLEY TUE NIGHT. THE UPPER LEVEL
FORCING WILL INTERACT WITH A SLOW MOVING NORTH-SOUTH RUNNING FRONTAL
BOUNDARY TO PRODUCE AREAS OF PCPN. MOST WOULD FALL AS RAIN...BUT
SOME MIX WITH AND THEN CHANGE OVER TO SNOW AS THE TROUGH EXITS LATE
TUE NIGHT IS LIKELY.
A BRIEF BREAK ON WED AS HIGH PRESSURE BUILDS IN...BUT IT JUST AS
QUICKLY EXITS SOUTHEAST ALLOWING FOR ANOTHER UPPER LEVEL SHORTWAVE
TROUGH TO DROP IN FROM THE NORTHWEST. GFS/EC BOTH IN AGREEMENT WITH
SPINNING THIS FEATURE ACROSS THE REGION WED NIGHT-THU...WITH MORE
LIGHT PCPN CHANCES RESULTING. MOSTLY RAIN...BUT THERE WOULD BE SOME
SNOW CHANCES TOO.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 644 AM CDT FRI APR 19 2013
CYCLONIC FLOW AROUND A LOW PRESSURE SYSTEM OVER UPPER MICHIGAN
WILL KEEP MVFR CLOUDS IN PLACE ACROSS THE REGION THROUGH 20.07Z.
IN ADDITION...THERE WILL BE ENOUGH INSTABILITY FOR SCATTERED
RAIN AND SNOW SHOW ERRS. THESE SHOWERS WILL OCCASIONALLY REDUCE
VISIBILITIES TO LESS THAN A MILE. WITH UNCERTAINTY ON WHEN THEY
WOULD AFFECT THE TAF SITES...THIS WAS NOT INCLUDED IN THE
FORECAST. 850 MB TO 950 MB LAPSE RATES WILL ALLOW 25 TO 30 KNOTS
WIND GUSTS TO MIX DOWN TO THE SURFACE THROUGH 20.04Z.
AS HIGH PRESSURE BUILDS ACROSS THE REGION AFTER 20.06Z...SKIES
WILL QUICKLY CLEAR.
&&
.HYDROLOGY...
ISSUED AT 255 AM CDT FRI APR 19 2013
FLOODING IS CURRENTLY OCCURRING ALONG PORTIONS OF THE BLACK AND
TREMPEALEAU RIVERS. RECENT RAINFALL WILL KEEP THOSE RIVERS ABOVE
FLOOD STAGE INTO THE EARLY WEEKEND.
WET CONDITIONS WILL PERSIST INTO THE EARLY PART OF THE NEW WORK
WEEK...BUT SIGNIFICANT ACCUMULATIONS ARE NOT EXPECTED THROUGH AT
LEAST MONDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...BOYNE
HYDROLOGY....BOYNE/RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
255 AM CDT FRI APR 19 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 255 PM CDT THU APR 18 2013
LATEST WATER VAPOR SATELLITE IMAGERY PLACED A SHORTWAVE TROUGH OVER
THE REGION...WITH TRENDS DRIVING IT EAST/NORTHEAST. GOOD MID LEVEL
DRY PUNCH ALSO INDICATED...WHICH SHOWS UP IN THE RAP BUFKIT
SOUNDINGS. THIS HAS RESULTED IN THE LOSS OF ICE IN SOME OF THE
CLOUD...AND MOSTLY AREAS OF DRIZZLE AHEAD OF TROUGH/UPPER LEVEL LOW.
DEPENDING ON SFC TEMPS...THERE COULD BE SOME PATCHY FREEZING
DRIZZLE. WEST-EAST RUNNING X-SECTION AND BUFKIT SOUNDINGS DO POINT
TO A RETURN OF THE ICE QUICKLY EARLY THIS MORNING...AND THUS EITHER
SNOW OR RAIN. GIVEN THE MOVEMENT OF THE SYSTEM...THE BETTER CHANCES
FOR ACCUMULATING PCPN WILL BE ACROSS THE NORTH...AND MOSTLY THIS
MORNING.
FOR THE AFTERNOON...RAP SOUNDINGS BUILD SOME SHALLOW NEAR SFC
INSTABILITY...UP TO AROUND 800 MB. 1000-850 MB LAPSE RATES ARE
AROUND 8.5 C/KM. ENOUGH LOW LEVEL SATURATION THAT THIS INSTABILITY
SHOULD RESULT IN SCT/WIDESPREAD SHOWERS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 255 AM CDT FRI APR 19 2013
RELATIVELY STRONG 925-850 MB WARM AIR ADVECTION AND ISENTROPIC
UPGLIDE ON THE 280-290 K SFCS SLATED TO MOVE ACROSS THE FORECAST
AREA BETWEEN 06Z SUN - 00Z MON. THE LOW LEVEL THERMODYNAMIC FORCING
IS AHEAD OF A SHORTWAVE TROUGH SLATED TO DROP SOUTHEAST OVER THE
NORTHERN PLAINS SUN AFTERNOON...AND BE A PLAYER IN PCPN CHANCES FOR
THE REGION FOR THE EARLY PART OF THE NEW WORK WEEK. A FEW PIECES OF
UPPER LEVEL ENERGY AHEAD OF THE TROUGH...WHICH WOULD ADD TO THE
FORCING MIX FOR SUN. WEST-EAST RUNNING X-SECTION POINTS TO
INCREASING SATURATION BY 06Z SUN...DEEP ENOUGH AND COLD ENOUGH FOR
THERE TO BE ICE IN THE CLOUD. PRETTY GOOD CHANCE FOR SOME PCPN WITH
THE LOW LEVEL FORCING...WITH A SNOW/RAIN MIX INITIALLY CHANGING OVER
TO RAIN DURING THE DAY SUNDAY. A HINT OF INSTABILTY IN NAM BUFKIT
SOUNDINGS...BUT NOT MUCH/IF ANY IN THE GFS. WILL KEEP THUNDER
MENTION OUT OF THE FORECAST FOR NOW.
THE TROUGH/S SFC LOW/COLD FRONT SWING IN SUN NIGHT. GFS AND NAM AT
ODDS WITH THE TIMING...WITH THE 19.00Z NAM BRINGING THE FRONT TO THE
MISSISSIPPI RIVER AROUND 03Z MON...WITH THE GFS HOLDING OFF UNTIL
CLOSER TO 12Z MON. THE EC AND GEM ARE CLOSER TO THE GFS. WILL LIKELY
LEAN THIS WAY FOR TIMING. WITH SOME LOW LEVEL MOISTURE RETURN AHEAD
OF THE FRONT...IT WILL SERVE AS ANOTHER FOCUS FOR PCPN GENERATION.
THE GFS AND EC SWING BITS OF UPPER LEVEL ENERGY ACROSS THE REGION
SUN NIGHT-TUE NIGHT...AHEAD OF AN UPPER LEVEL TROUGH WHICH MOVES
OVER THE UPPER MISSISSIPPI RIVER VALLEY TUE NIGHT. THE UPPER LEVEL
FORCING WILL INTERACT WITH A SLOW MOVING NORTH-SOUTH RUNNING FRONTAL
BOUNDARY TO PRODUCE AREAS OF PCPN. MOST WOULD FALL AS RAIN...BUT
SOME MIX WITH AND THEN CHANGE OVER TO SNOW AS THE TROUGH EXITS LATE
TUE NIGHT IS LIKELY.
A BRIEF BREAK ON WED AS HIGH PRESSURE BUILDS IN...BUT IT JUST AS
QUICKLY EXITS SOUTHEAST ALLOWING FOR ANOTHER UPPER LEVEL SHORTWAVE
TROUGH TO DROP IN FROM THE NORTHWEST. GFS/EC BOTH IN AGREEMENT WITH
SPINNING THIS FEATURE ACROSS THE REGION WED NIGHT-THU...WITH MORE
LIGHT PCPN CHANCES RESULTING. MOSTLY RAIN...BUT THERE WOULD BE SOME
SNOW CHANCES TOO.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1151 PM CDT THU APR 18 2013
THE FOCUS AT THE TAF SITES IS WITH THE BAND OF SNOW CURRENTLY
MOVING ACROSS SOUTH CENTRAL MINNESOTA AND WHETHER IT WILL CLIP RST
OR LSE. CURRENT TRENDS FAVOR THAT IT WILL MISS THEM TO THE NORTH
WITH JUST LIGHT SNOW AND/OR DRIZZLE POSSIBLE THROUGH THE NIGHT.
WITH THE SYSTEM STARTING TO LIFT TO THE NORTHEAST...THERE APPEARS
TO BE SOME DRYING OF THE LOW LEVEL AIR MASS WITH CONDITIONS
IMPROVING TO MVFR THROUGH MUCH OF IOWA AND SOUTHERN WISCONSIN.
BASED ON THIS...HAVE PLAYED A GENERAL IMPROVING TREND THROUGH
TOMORROW EVENING WITH CEILINGS COMING UP. IT DOES APPEAR AS THOUGH
THERE MAY BE SOME RAIN OR SNOW SHOWERS THAT DEVELOP IN THE LATE
MORNING TO AFTERNOON HOURS ALONG THE MISSISSIPPI RIVER...BUT
CONFIDENCE IS NOT HIGH ENOUGH AT THIS POINT TO PUT IN SOME TRENDS
FOR LOWER VISIBILITIES THAT WOULD LIKELY LAST FOR A HALF HOUR AT A
TIME. SEEMS LIKE A SCENARIO WHERE TEMPO GROUPS WOULD BE NECESSARY
FOR SOME POTENTIAL BRIEF IFR CONDITIONS.
&&
.HYDROLOGY...
ISSUED AT 255 AM CDT FRI APR 19 2013
FLOODING IS CURRENTLY OCCURRING ALONG PORTIONS OF THE BLACK AND
TREMPEALEAU RIVERS. RECENT RAINFALL WILL KEEP THOSE RIVERS ABOVE
FLOOD STAGE INTO THE EARLY WEEKEND.
WET CONDITIONS WILL PERSIST INTO THE EARLY PART OF THE NEW WORK
WEEK...BUT SIGNIFICANT ACCUMULATIONS ARE NOT EXPECTED THROUGH AT
LEAST MONDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION.....HALBACH
HYDROLOGY....BOYNE/RIECK
AREA FORECAST DISCUSSION
NWS MIAMI FL
1009 AM EDT FRI APR 19 2013
.UPDATE...
A FEW LIGHT SHOWERS CONTINUE TO PUSH ONSHORE THE ATLANTIC COAST
UNDER SOUTHEAST FLOW. THESE SHOWERS ARE VERY LIGHT AND WILL
CONTINUE TO PUSH NORTHWEST ACROSS BROWARD AND MIAMI-DADE COUNTIES
THROUGH THE MORNING. LATEST HRRR INITIALIZED WELL AND KEEPS THESE
SHOWERS AND POSSIBLY A FEW THUNDERSTORMS ACROSS NORTHERN INTERIOR
AREAS THROUGH THE AFTERNOON. INCREASED POPS SLIGHTLY ACROSS THE
EAST COAST AND ADJUSTED TEMPERATURES TO ACCOUNT FOR CURRENT
TRENDS...OTHERWISE CURRENT FORECAST IS ON TRACK. UPDATE SENT.
&&
.PREV DISCUSSION... /ISSUED 808 AM EDT FRI APR 19 2013/
AVIATION...
VFR CONDITIONS WILL PREVAIL THROUGH THE NEXT 24 HOURS OUTSIDE ANY
BRIEF PERIODS OF SHOWERS AND/OR A STORMS IN THE VICINITY OF THE
SITES ALTHOUGH THOSE CHANCES ARE SMALL AT THE PRESENT TIME. SE
WINDS OF 10-15 KNOTS AND GUSTY ALONG SE COAST TODAY BECOMING
5-10KT OVERNIGHT. AT KAPF SSE WIND OF 10 TO 15 KNOTS AND GUSTY
BECOMING SSW LATE THIS AFTERNOON FOR A COUPLE OF HOURS AND SE
5-10KT OVERNIGHT.
PREV DISCUSSION... /ISSUED 341 AM EDT FRI APR 19 2013/
DISCUSSION...
THE GUIDANCE HAS BEEN VERY CONSISTENT INDICATING THAT A COLD FRONT
WILL ENTER THE FLORIDA PANHANDLE LATER TODAY THEN CONTINUE TO MOVE
SOUTHEAST INTO NORTH CENTRAL FLORIDA ON SATURDAY AND THEN STALL
WHILE BECOMING SOMEWHAT DIFFUSE LATE SATURDAY THROUGH SUNDAY. AT
THE MID TO UPPER LEVELS...A WEAK RIDGE TODAY WILL ERODE BY THE
WEEKEND WITH A MID TO UPPER LEVEL TROUGH DIGGING INTO THE EASTERN
AND CENTRAL GULF WITH THE FLORIDA PENINSULA TO THE EAST OF THE
TROUGH AXIS.
FOR TODAY...A MODERATE SOUTHEASTERLY FLOW WILL PREVAIL ACROSS THE
REGION WITH INCREASING MOISTURE AS THE DAY PROGRESSES WITH
REGIONAL PWATS REACHING ABOUT 1.5 INCHES LATER TODAY. GIVEN THE
INCREASING MOISTURE AND ELEVATED DEW POINTS ACROSS THE
REGION...FOR THIS AFTERNOON ISOLATED THUNDERSTORMS WILL BE
POSSIBLE BUT MAINLY EXPECTED IN THE INTERIOR REGIONS AND WEST. IF
THE WEST COAST SEA BREEZE DEVELOPS LATER THIS AFTERNOON SCATTERED
SHOWER AND THUNDERSTORM ACTIVITY IS POSSIBLE IN THE WESTERN
INTERIOR AND IS INDICATED IN THE FORECAST.
FOR THE WEEKEND...THE GUIDANCE HAS BEEN CONSISTENTLY INDICATING
THAT DEEPER LAYERED MOISTURE IS EXPECTED TO ENTER THE REGION AND
A MID TO UPPER LEVEL TROUGH DEVELOPING WEST OF THE FLORIDA PENINSULA.
IN ADDITION SYNOPTIC SCALE LIFT IS FORECAST FOR THE MID TO UPPER
LEVELS. ALL THESE ELEMENTS WILL RESULT IN THE POTENTIAL FOR
CONVECTION ACROSS THE REGION SATURDAY AND SUNDAY. FORECAST
SOUNDINGS INDICATE THAT PWATS COULD REACH NEAR 1.8 INCHES LATER
ON SATURDAY BUT THE SOUNDINGS SO FAR DO NOT INDICATE A WIND
PROFILE OR THERMODYNAMIC PROFILE THAT MAY SUPPORT SEVERE
THUNDERSTORMS OR WEATHER. FOR SATURDAY...MAINLY AFTERNOON AND EARLY
EVENING SCATTERED SHOWERS AND THUNDERSTORMS ARE FORECAST WITH THE
COVERAGE POSSIBLY GREATER ALONG THE EASTERN THIRD OF THE PENINSULA
AND THE ADJACENT GULF WATERS. VERY SIMILAR CONDITIONS ARE EXPECTED
ON SUNDAY AFTERNOON ALTHOUGH THE FORECAST SOUNDINGS INDICATE THAT
THE MID LEVELS WILL COOL AND THE MID TO UPPER LEVEL TROUGH MAY BE
IN A MORE FAVORABLE POSITION TO SUPPORT MORE ORGANIZED CONVECTION.
FOR NOW...ON SUNDAY MAINLY SCATTERED SHOWERS AND THUNDERSTORMS ARE
FORECAST BUT WOULD NOT BE SURPRISED IF THE FUTURE GUIDANCE
INDICATES MORE WIDESPREAD COVERAGE.
FOR THE EXTENDED PERIODS...GUIDANCE INDICATES THAT LINGERING
MOISTURE ACROSS THE REGION ON MONDAY AND FAVORABLE MID TO UPPER
LEVELS MAY ALLOW FOR A CHANCE OF SHOWERS AND THUNDERSTORMS. AFTER
MONDAY NORMAL DIURNALLY DRIVEN SHOWERS AND ISOLATED THUNDERSTORMS
MAY BE POSSIBLE FOR THE REMAINDER OF THE WEEK.
MARINE...
WINDS AND SEAS MAINLY EXPECTED TO BE BELOW ADVISORY LEVELS THROUGH
THE FORECAST PERIOD BUT OVER THE WEEKEND THUNDERSTORMS ARE
FORECAST AND WINDS AND SEAS COULD BE LOCALLY HIGHER IN OR NEAR
THUNDERSTORMS.
FIRE WEATHER...
NO FIRE WEATHER CONCERNS BUT OVER THE WEEKEND THUNDERSTORMS ARE
FORECAST WITH A SLIGHT CHANCE OF SEVERE WEATHER.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 85 74 84 70 / 20 30 50 40
FORT LAUDERDALE 85 76 84 72 / 20 30 50 40
MIAMI 86 75 84 72 / 20 20 50 40
NAPLES 89 72 84 68 / 30 20 40 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...13/SI
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1100 AM EDT FRI APR 19 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION FROM WEST TO EAST THIS
AFTERNOON AND EVENING. WIDESPREAD SHOWERS AND THUNDERSTORMS ARE
EXPECTED ALONG AND AHEAD OF THE BOUNDARY. CANADIAN HIGH PRESSURE
WILL BUILD INTO THE REGION LATE TONIGHT THROUGH SUNDAY...BRINGING
DRY AND COOL CONDITIONS. HIGH PRESSURE WILL REMAIN OVERHEAD EARLY
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
14Z SURFACE OBSERVATIONS INDICATE COLD FRONT HAS REACHED FAR
EASTERN OH AND KY...AND WILL CROSS INTO WESTERN WV SOON. THE FRONT
WILL CONTINUE TO PUSH EASTWARD...AND IS STILL EXPECTED TO REACH
EASTERN WV BY EARLY AFTERNOON AND SWEEP ACROSS THE FORECAST AREA
FROM MID AFTERNOON THROUGH THIS EVENING.
THE PRESSURE GRADIENT BETWEEN THE APPROACHING COLD FRONT AND HIGH
PRESSURE OVER THE ATLANTIC CONTINUES TO INCREASE. WIND GUSTS
BETWEEN 15-20 MPH HAVE DEVELOPED OVER MOST OF THE FORECAST AREA.
WINDS WILL CONTINUE TO INCREASE THIS AFTERNOON WITH GUSTS UP TO 30
TO 35 MPH.
IN TERMS OF SEVERE THUNDERSTORM THREAT...12Z KIAD INDICATED A CAP
AROUND 700MB. HOWEVER...MODEL SOUNDINGS INDICATE THIS LAYER WILL
COOL BY A FEW DEGREES THIS AFTERNOON...WHILE DIURNAL SURFACE
HEATING CONTINUES. BIG VARIABLE WILL CONTINUE TO BE CLOUD COVER
AND ITS INFLUENCE ON INSTABILITY. FORECAST SOUNDINGS INDICATE
POTENTIAL FOR SOME BREAKS IN CLOUD COVER...AND THESE ARE BEING
OBSERVED IN PARTS OF WV AT THIS HOUR. THIS WOULD ENABLE CAPE TO
APPROACH 1000 J/KG OVER SOME LOCATIONS AT LEAST BRIEFLY. OTHERWISE
FORECAST IN ON TRACK FOR INCREASING MOISTURE DUE TO SOUTHERLY
FLOW AND A VERY STRONG JET OVER THE AREA WITH 50+KT WINDS ABOVE
850MB AHEAD OF THE FRONT. SPC HAS INCREASED SLIGHT RISK AREA TO
INCLUDE ALL OF THE FORECAST AREA FROM THE SHENANDOAH VALLEY
EWD...AND HI-RES MODELS LIKE THE HRRR INDICATE THE POTENTIAL FOR
AN ORGANIZED LINE OF SHOWERS/TSTMS TO DEVELOP AS THE FRONT
APPROACHES THIS AFTERNOON. ANY THUNDERSTORMS WILL HAVE POTENTIAL
TO TAP INTO THE STRONG WINDS ALOFT AND PRODUCE DAMAGING WINDS.
HODOGRAPHS ALSO INDICATE SOME POTENTIAL TORNADO RISK...ESPECIALLY
IF EMBEDDED SUPERCELLS DEVELOP WITH THE LINE OF THUNDERSTORMS.
THE COLD FRONT WILL MOVE OFF TO OUR EAST OVERNIGHT AND ANY
LEFTOVER SHOWERS WILL ALSO MOVE OUT OF OUR AREA. MIN TEMPS
OVERNIGHT WILL BE NOTICEABLY CHILLIER COMPARED TO RECENT
NIGHT...RANGING FROM THE 20S ALONG THE RIDGE TOPS IN THE POTOMAC
HIGHLANDS...TO THE MID AND UPPER 40S NEAR
WASHINGTON/BALTIMORE...TO THE LOWER 50S ACROSS SOUTHERN MARYLAND.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
HIPRES BLDS OVER THE RGN THIS WKND. WL BE IN CAA REGIME MOST OF THE
TIME...W/ NW/NLY FLOW SAT BCMG NE/ELY SUN AS CENTER OF HIGH HEADS
TWD NEW ENGLND/QUE. SHUD BE DIURNAL CU SAT...SPCLY IN THE MTNS. BY
SUN...SUBSIDENCE SHUD PREVAIL.
TEMPS WL BE BLO CLIMO SAT...AND DROP A CPL MORE BY SUN. LTST
MOS/GOING FCST IN GOOD AGREEMENT. GROWING SEASON HAS STARTED E OF
BLURDG. ALTHO IT WL BE CHILLY SAT NGT...A LGT NLY BRZ AS CURRENTLY
PROGGED WUD PRECLUDE EITHER FROST OR SUBFRZG TEMPS. RECENT TEMP BIAS
HAS BEEN TO FCST TOO COLD. WL OMIT FROM HWO ATTM AS POTL FOR
HEADLINE CONDS SLIM.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
MODEL GUIDANCE STILL INDICATING CAD SCENARIO DEVELOPING LATE IN THE
WEEKEND ONCE THE CENTER OF THE SFC HIGH SHIFTS EWD INTO SERN CANADA.
WEDGE OF COOLER AIR WILL SPILL SWD INTO THE MID-ATLANTIC REGION. THE
1040 MB HIGH WILL GRADUALLY PROGRESS EWD TOWARD THE CANADIAN
MARITIME...RESULTING IN ELY FLOW IN OUR AREA ERY NEXT WEEK. GIVEN
THE THE STILL COOL WATERS THIS TIME OF YR...CAD INVERSIONS ARE
DIFFICULT TO ERODE AND THUS HAVE THE POTENTIAL TO PERSIST FOR A
MULTI-DAY PERIOD ONCE AN OCEAN FETCH BECOMES ESTABLISHED. THIS MAY
BE THE CASE ERY NEXT WEEK. THE LATEST RUN OR TWO OF THE ECWMF...GFS
AND ITS ENSEMBLE MEAN SHOW AN INVERTED TROUGH DEVELOPING EAST OF
THIS CAD RIDGE BUT HAS BACKED OFF ON LOPRES DEVELOPMENT THAT TRACKS
CLOSE TO THE COAST. THUS KEPT MON-TUE FCST MAINLY DRY EXCEPT FOR LOW
CHANCE POPS NEAR THE CHSPK BAY. NONETHELESS...MARINE INFLUENCE WILL
RESULT IN CLOUDY CONDITIONS AND COOLER THAN NORMAL TEMPS.
COLD FRONT APPROACHES NEXT WED OR THU. STILL SOME UNCERTAINTY HOW
MUCH OF A WARMING TREND OCCURS MIDWEEK IN PRE-FRONTAL WARM SECTOR.
AS STATED ABOVE...CAD SETUP OFTEN TAKES LONGER TO ERODE...OFTEN
LONGER THAN MODELS INDICATE.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
MOSTLY MVFR CIGS LATE THIS MORNING. MODELS INDICATE POTENTIAL FOR
LOWER CLOUDS TO ERODE FOR A WHILE TODAY...SO AMENDMENTS UP TO VFR
AND POSSIBLE. SOUTHERLY WINDS WILL INCREASE WITH GUSTS AROUND 30
KNOTS EXPECTED.
A STRONG COLD FRONT WILL PASS THROUGH THE TERMINALS LATE THIS
AFTERNOON AND EVENING. A LINE OF HEAVY SHOWERS AND THUNDERSTORMS IS
EXPECTED ALONG AND AHEAD OF THE COLD FRONT. THUNDERSTORMS WILL BE
CAPABLE OF PRODUCING GUSTY WINDS. TAFS MAY NEED TO BE AMENDED
LATER TO ADJUST TIMING OF THESE SHOWERS/STORMS.
HIPRES OVR THE TERMINALS THIS WKND. NW WNDS SAT G20-25KT...BCMG NLY
AND DIMINISHING SAT NGT...AND VEERING ELY SUN.
ONSHORE FLOW DEVELOPS LATE IN THE WEEKEND AS HIPRES SHIFTS OFF THE
NEW ENGLAND COAST. THERE IS A POTENTIAL FOR AN EXTENDED PERIOD OF
LOW CLOUDS AND FOG ERY NEXT WEEK IF ONSHORE FLOW PERSISTS.
&&
.MARINE...
HAVE UPGRADED TO A GALE WARNING OVER ALL WATERS FROM 2PM TO 10PM.
SOUTHERLY WINDS ARE EXPECTED TO GRADUALLY INCREASE IN INTENSITY AS
THE PRESSURE GRADIENT INCREASES AHEAD OF AN APPROACHING COLD
FRONT. A LINE OF HEAVY SHOWERS AND THUNDERSTORMS IS EXPECTED ALONG
AND JUST AHEAD OF THE COLD FRONT. THE BEST CHANCE FOR THE HEAVIER
PRECIPITATION OVER THE WATERS WILL BE BETWEEN ABOUT 6 PM AND
MIDNIGHT. THUNDERSTORMS WILL BE CAPABLE OF PRODUCING GUSTY WINDS.
SPECIAL MARINE WARNINGS MAY BE NEEDED WITH THESE THUNDERSTORMS IF
WIND GUSTS REACH STORM FORCE.
THE COLD FRONT WILL MOVE OFF TO THE EAST LATE TONIGHT AND WINDS WILL
SHIFT TO THE NORTHWEST. SMALL CRAFT ADVISORIES WILL LIKELY BE
NEEDED AFTER THE GALE EXPIRES.
HIPRES BLDS ACRS THE WATERS THIS WKND. GOOD CAA SAT WL LEAD TO FVRBL
MOMENTUM TRANSFER AND RATHER HIGH MIXING HGTS. THIS WL PROMOTE 20-25
KT WNDS ACRS THE WATERS. HV ADDED SCA FOR ALL WATERS THRU 21Z. A
PRES SURGE MAY FLLW DOWN THE BAY SAT NGT.
BY SUN...THE SFC HIGH HEADS TWD NEW ENGLND...LEADING TO ELY FLOW ON
THE WATERS. WSPDS SHUD BE LIGHTER /UNDER SCA LVLS/. THE NELY/ELY
PTTN MAY LAST FOR A CPL DAYS.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES CURRENTLY RUNNING AROUND 1 OR 1.1 FEET LATE THIS
MORNING. AS NOTED IN EARLIER DISCUSSION...ANOMALIES WILL NEED TO
INCREASE MORE IN ORDER TO WARRANT A COASTAL FLOOD ADVISORY. WILL
CONTINUE TO MONITOR.
PREVIOUS DISCUSSION...
TIDAL DEPARTURES RUNNING BETWEEN A HALF-FT AND 1 FT
ABV ASTRO NORMS ATTM. A STIFF SLY FLOW ONGOING...WHICH WL ONLY
INCREASE TDA AHEAD OF APPROACHING CDFNT. THEREFORE...DO ANTICIPATE
DEPARTURES TO INCREASE FURTHER...WITH THE PM TIDE CYCLE THE ONE TO
WATCH. HOWEVER...WE/RE AT HALF- MOON...WHICH IS PROVIDING US WITH
SOME WIGGLE ROOM. DEPARTURES WILL NEED TO BE AROUND 1.5 FT FOR
MOST SITES TO REACH MINOR FLOOD THRESHOLDS. ANNAPOLIS MOST
SUSCEPTIBLE AT 1.2 FT. CBOFS /ADJUSTED FOR HIGH BIAS/ AND ESTOFS
BOTH SUGGEST THAT THE TIDE WL CREST ABOVE CAUTION STAGE BUT BELOW
MINOR FLOOD. FOR DC ...HEC-RAS ALSO SUGGESTS THAT THE TIDE WL BE
UNDER FLOOD STAGE. THEREFORE...WL BE WITHHOLDING ANY ADVISORIES AT
THIS TIME. HOWEVER...CONSIDERING MARGIN FOR ERROR...ITS CLOSE
ENOUGH TO WARRANT A CONTINUING MENTION IN HWO.
DEPARTURES SHOULD BE LOWER FOR THE AM CYCLE SAT...BUT BLOWOUT CONDS
MAY NOT BE REALIZED TIL LATE SAT-SAT NGT.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR
ANZ530>543.
GALE WARNING FROM 2 PM THIS AFTERNOON TO 10 PM EDT THIS
EVENING FOR ANZ530>543.
&&
$$
SYNOPSIS...BJL/KCS
NEAR TERM...BJL/KCS
SHORT TERM...HTS
LONG TERM...JRK
AVIATION...BJL/KCS/HTS
MARINE...JRK/BJL/KCS/HTS
TIDES/COASTAL FLOODING...HTS/KCS
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1233 PM CDT FRI APR 19 2013
.UPDATE...
ISSUED AT 1115 AM CDT FRI APR 19 2013
CENTER OF POWERFUL STORM SYSTEM THAT HAS IMPACTED US WITH TSRA THE
PAST COUPLE OF DAYS NOW ENTERING WRN LAKE SUPERIOR AND CONTINUES
TO MOVE NE. A DEEP TROF EXISTS OVER THE CNTRL CONUS IN THE WAKE OF
THIS STORM AND HAS GIVEN US OUR RATHER CHILLY MORNING. THERE IS
ANOTHER REASONABLY STRONG VORT MAX OVER SRN SD SLIDING DOWN THE
BACKSIDE OF THIS TROF HEADING OUR WAY...TO THE SE. EXTENSIVE AREA
OF SC CLOUDS EXISTS OVER MUCH OF THE BI-STATE REGION WITH THE
BACKEDGE HAVING MOVED THRU CNTRL MO. HOWEVER...AND AS EXPECTED...
THIS BACKEDGE HAS BECOME MORE DIFFUSE OVER THE PAST HOUR AS
DIURNAL INFLUENCES HAVE BEGUN TO KICK IN WITH STRONG APRIL SUN AND
THIS SHOULD SERVE TO SLOW DOWN THE CLEARING WITH ADDITIONAL CLOUDS
ON THIS EDGE. TEMPS REMAIN WELL BELOW AVERAGE AT 16Z/11AM...WITH
READINGS IN THE UPR 30S AND LO 40S...W SFC WNDS ARE GUSTING TO
30-35MPH.
MAIN FCST PROBLEM WILL BE IMPACT OF THE SHORTWAVE HEADING OUR WAY
LATER TODAY. NEW 12Z MODELS AS WELL AS LATEST RAP AND HRRR ALL
TAKE THE HEART OF THIS VORT MAX AND ITS ASSOCIATED H300 SPEED MAX
THRU CNTRL MO AND SRN IL...AND WITH THE CYCLONIC CURVATURE AT
THE BASE OF THE TROF...WILL CURL THE BEST LIFT ASSOCIATED WITH
THESE FEATURES ON ITS LEFT FLANK...OR FOR PARTS OF THE NRN AND
NERN FA. THERE WILL ALSO BE SLIGHTLY BETTER LO LEVEL CONVERGENCE
SETTING UP IN THOSE AREAS AS WELL. SO IF ANYTHING IS GOING TO
HAPPEN...IT LOOKS LIKE MAINLY W-CNTRL AND PARTS OF SW IL. VERY
MARGINAL MOISTURE AND INSTABILITY SHOULD LIMIT PCPN TO SHRA AND
WILL PROBABLY BE ISOLD AT BEST. 20PCT POPS THUS STILL LOOK
JUSTIFIED BUT HAVE SHIFTED THE TIMING BACK FOR LATE THIS AFTERNOON
INSTEAD OF EARLIER IN THE DAY. SOME PCPN...IF IT DEVELOPS...MAY
EVEN LAST BRIEFLY PAST 00Z.
OTHERWISE...TEMPS AND WINDS LOOK ON TARGET...WITH MAXES IN THE
45-50 RANGE...OR ALMOST 20F BELOW AVERAGE...AND GUSTY W SFC WNDS
30-35MPH.
TES
&&
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 350 AM CDT FRI APR 19 2013
CENTER OF INTENSE STORM SYSTEM WILL BE SPINNING ITS WAY FROM THE
UPPER GREAT LAKES INTO SOUTHERN CANADA TODAY. THIS PUTS THE FA IN
THE WINDY AND COLD WAKE OF THE SYSTEM...WHICH MEANS TODAYS WEATHER
WILL BE CHARACTERIZED BY STRONG WEST-NORTHWEST WINDS AND TEMPS THAT
WILL BE WELL BELOW NORMAL.
EXTENSIVE SC DECK BLANKETS THE REGION EARLY TODAY...AND RAGGED BACK
EDGE OF THE CLOUDS RUNS FROM W IA TO NEAR THE MO/KS BORDER AT 08Z.
AS LOW CONTINUES TO PULL AWAY FROM THE AREA BELIEVE THAT THE BACK
EDGE OF THE CLOUD DECK WILL SWEEP EAST. SOMEWHAT OFFSETTING THIS
CLEARING SHOULD BE DIURNAL CLOUD DEVELOPMENT DUE TO THE COLD TEMPS
AND AMPLE LOW LEVEL MOISTURE...AND OUR N/NE COUNTIES SHOULD SEE MORE
COVERAGE OF THESE HOME-GROWN CLOUDS DUE TO SOMEWHAT DEEPER CYCLONIC
CURVATURE OVER THIS PART OF THE CWA.
MOS GUIDANCE FOR MAX TEMPS LOOKS TO BE IN THE BALLPARK. VALUES ARE
SUPPORTED BY CONDITIONAL CLIMATOLOGY WHICH SUGGESTS A 10-18 DEGREE
WARMUP...AND ALSO DOVETAILS FAIRLY WELL WITH MAX TEMPS DERIVED FROM
THE PROGGED 850MB TEMPS AND THE THINKING THAT AT LEAST PARTIAL
SUNSHINE WILL ALLOW SOME ADDITIONAL WARMING.
TRUETT
.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 350 AM CDT FRI APR 19 2013
(TONIGHT THROUGH SUNDAY NIGHT)
MAIN ISSUE FOR TONIGHT WILL BE WHEN WILL CLOUDS CLEAR OUT AND HOW
COLD WILL IT GET. AS SYSTEM CONTINUES TO LIFT TO NORTHEAST THROUGH
SOUTHERN CANADA TONIGHT...WE CONTINUE TO BE IN WRAP AROUND FLOW WITH
GUSTY WEST TO NORTHWEST WINDS DIMINISHING BY 06Z. BUT WITH SO MUCH
LOW LEVEL MOISTURE DUE TO MAJOR RAINFALL PAST 36 HOURS...NOT SURE
HOW CONFIDENT I AM ABOUT FROST/FREEZE POTENTIAL. BUT WITH STUFF
BUDDING OUT OVER REGION...SKIES CLEARING OUT/WIND DIMINISHING AND LOWS
FORECAST IN THE UPPER 20S TO LOW 30S...WILL ERR ON SIDE OF CAUTION
AND ISSUE A FREEZE WARNING FOR FAR NORTHERN 6 COUNTIES AND FROST
ADVISORY FOR THE REMAINDER OF THE FORECAST AREA FROM 06Z TO 13Z
TONIGHT.
BEYOND THAT QUIET WEATHER IN STORE FOR THE WEEKEND WITH TEMPERATURES
MODERATING THROUGH THE PERIOD. HIGHS ON SATURDAY WILL BE IN THE MID
50S TO LOW 60S. LOWS SATURDAY NIGHT WILL BE WARMER...ONLY IN THE
UPPER 30S TO MID 40S. HIGHS WARMING UP INTO THE MID 60S EVERYWHERE
ON SUNDAY WITH LOWS SUNDAY NIGHT IN THE MID 40S...AHEAD OF NEXT
WEATHER SYSTEM.
(MONDAY THROUGH THURSDAY)
EXTENDED MODELS CONTINUE TO HAVE DIFFERENCES ON STRENGTH AND TIMING
OF NEXT WEATHER SYSTEM THAT WILL BEGIN TO AFFECT THE FORECAST AREA
ON MONDAY. FOR NOW HAVE SHOWERS AND THUNDERSTORMS MOVING INTO FAR
NORTHERN PORTIONS OF FORECAST AREA ON MONDAY. THEN SHOWERS AND
THUNDERSTORMS TO INCREASE IN COVERAGE MONDAY NIGHT THROUGH
TUESDAY...BEFORE TAPERING OFF FROM WEST TO EAST ON TUESDAY NIGHT.
TEMPERATURES TO REMAIN NEAR NORMAL ON MONDAY IN THE MID TO UPPER
60S...THEN DROP OFF INTO THE LOW TO MID 50S BY WEDNESDAY AS SURFACE
RIDGE BUILDS IN. COOL OFF NOT TO LAST LONG AS TEMPERATURES BEGIN TO
MODERATE ON THURSDAY...WARMING UP INTO THE UPPER 50S TO LOW 60S.
BYRD
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1233 PM CDT FRI APR 19 2013
VFR CONDITIONS WILL PREVAIL AREAWIDE THRU THE VALID TAF PERIOD.
CIGS OVER MUCH OF THE AREA WILL GIVE WAY TO CLEARING THIS EVENING
WITH HI CIGS RETURNING ON SATURDAY. GUSTY W SFC WNDS WILL DIMINISH
SIGNIFICANTLY THIS EVENING WITH LOSS OF HEATING AND APPROACH OF HI
PRES AND LIGHT WINDS TO THEN CONTINUE INTO SATURDAY. OUTSIDE CHC
OF -SHRA OR SPRINKLES LATER THIS AFTERNOON OR EARLY THIS EVENING
WITH UPPER LEVEL DISTURBANCE MOVING THRU AT THAT TIME...BUT PERFER
TO SEE RADAR RETURNS FIRST ON SUCH LO PROB SITUATIONS.
SPECIFICS FOR KSTL...VFR THRU THE PERIOD...GUSTY W SFC WNDS THIS
AFTERNOON BECOMING LIGHT W-NW THIS EVENING AND CONTINUING INTO
SATURDAY. POTENTIAL OF SOME SPRINKLES LATER THIS AFTERNOON AND
EARLY EVENING BUT WILL LEAVE OUT UNTIL WE SEE SOME RADAR RETURNS
AND CONFIDENCE INCREASES.
TES
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...FROST ADVISORY FROM 1 AM TO 8 AM CDT SATURDAY FOR AUDRAIN MO-
BOONE MO-CALLAWAY MO-COLE MO-CRAWFORD MO-FRANKLIN MO-
GASCONADE MO-IRON MO-JEFFERSON MO-LINCOLN MO-MADISON MO-
MONITEAU MO-MONROE MO-MONTGOMERY MO-OSAGE MO-PIKE MO-RALLS
MO-REYNOLDS MO-ST. CHARLES MO-ST. FRANCOIS MO-ST. LOUIS
CITY MO-ST. LOUIS MO-STE. GENEVIEVE MO-WARREN MO-WASHINGTON
MO.
FREEZE WARNING FROM 1 AM TO 8 AM CDT SATURDAY FOR KNOX MO-LEWIS
MO-MARION MO-SHELBY MO.
IL...FROST ADVISORY FROM 1 AM TO 8 AM CDT SATURDAY FOR BOND IL-
CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL-JERSEY IL-
MACOUPIN IL-MADISON IL-MARION IL-MONROE IL-MONTGOMERY IL-
PIKE IL-RANDOLPH IL-ST. CLAIR IL-WASHINGTON IL.
FREEZE WARNING FROM 1 AM TO 8 AM CDT SATURDAY FOR ADAMS IL-BROWN
IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1115 AM CDT FRI APR 19 2013
.UPDATE...
ISSUED AT 1115 AM CDT FRI APR 19 2013
CENTER OF POWERFUL STORM SYSTEM THAT HAS IMPACTED US WITH TSRA THE
PAST COUPLE OF DAYS NOW ENTERING WRN LAKE SUPERIOR AND CONTINUES
TO MOVE NE. A DEEP TROF EXISTS OVER THE CNTRL CONUS IN THE WAKE OF
THIS STORM AND HAS GIVEN US OUR RATHER CHILLY MORNING. THERE IS
ANOTHER REASONABLY STRONG VORT MAX OVER SRN SD SLIDING DOWN THE
BACKSIDE OF THIS TROF HEADING OUR WAY...TO THE SE. EXTENSIVE AREA
OF SC CLOUDS EXISTS OVER MUCH OF THE BI-STATE REGION WITH THE
BACKEDGE HAVING MOVED THRU CNTRL MO. HOWEVER...AND AS EXPECTED...
THIS BACKEDGE HAS BECOME MORE DIFFUSE OVER THE PAST HOUR AS
DIURNAL INFLUENCES HAVE BEGUN TO KICK IN WITH STRONG APRIL SUN AND
THIS SHOULD SERVE TO SLOW DOWN THE CLEARING WITH ADDITIONAL CLOUDS
ON THIS EDGE. TEMPS REMAIN WELL BELOW AVERAGE AT 16Z/11AM...WITH
READINGS IN THE UPR 30S AND LO 40S...W SFC WNDS ARE GUSTING TO
30-35MPH.
MAIN FCST PROBLEM WILL BE IMPACT OF THE SHORTWAVE HEADING OUR WAY
LATER TODAY. NEW 12Z MODELS AS WELL AS LATEST RAP AND HRRR ALL
TAKE THE HEART OF THIS VORT MAX AND ITS ASSOCIATED H300 SPEED MAX
THRU CNTRL MO AND SRN IL...AND WITH THE CYCLONIC CURVATURE AT
THE BASE OF THE TROF...WILL CURL THE BEST LIFT ASSOCIATED WITH
THESE FEATURES ON ITS LEFT FLANK...OR FOR PARTS OF THE NRN AND
NERN FA. THERE WILL ALSO BE SLIGHTLY BETTER LO LEVEL CONVERGENCE
SETTING UP IN THOSE AREAS AS WELL. SO IF ANYTHING IS GOING TO
HAPPEN...IT LOOKS LIKE MAINLY W-CNTRL AND PARTS OF SW IL. VERY
MARGINAL MOISTURE AND INSTABILITY SHOULD LIMIT PCPN TO SHRA AND
WILL PROBABLY BE ISOLD AT BEST. 20PCT POPS THUS STILL LOOK
JUSTIFIED BUT HAVE SHIFTED THE TIMING BACK FOR LATE THIS AFTERNOON
INSTEAD OF EARLIER IN THE DAY. SOME PCPN...IF IT DEVELOPS...MAY
EVEN LAST BRIEFLY PAST 00Z.
OTHERWISE...TEMPS AND WINDS LOOK ON TARGET...WITH MAXES IN THE
45-50 RANGE...OR ALMOST 20F BELOW AVERAGE...AND GUSTY W SFC WNDS
30-35MPH.
TES
&&
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 350 AM CDT FRI APR 19 2013
CENTER OF INTENSE STORM SYSTEM WILL BE SPINNING ITS WAY FROM THE
UPPER GREAT LAKES INTO SOUTHERN CANADA TODAY. THIS PUTS THE FA IN
THE WINDY AND COLD WAKE OF THE SYSTEM...WHICH MEANS TODAYS WEATHER
WILL BE CHARACTERIZED BY STRONG WEST-NORTHWEST WINDS AND TEMPS THAT
WILL BE WELL BELOW NORMAL.
EXTENSIVE SC DECK BLANKETS THE REGION EARLY TODAY...AND RAGGED BACK
EDGE OF THE CLOUDS RUNS FROM W IA TO NEAR THE MO/KS BORDER AT 08Z.
AS LOW CONTINUES TO PULL AWAY FROM THE AREA BELIEVE THAT THE BACK
EDGE OF THE CLOUD DECK WILL SWEEP EAST. SOMEWHAT OFFSETTING THIS
CLEARING SHOULD BE DIURNAL CLOUD DEVELOPMENT DUE TO THE COLD TEMPS
AND AMPLE LOW LEVEL MOISTURE...AND OUR N/NE COUNTIES SHOULD SEE MORE
COVERAGE OF THESE HOME-GROWN CLOUDS DUE TO SOMEWHAT DEEPER CYCLONIC
CURVATURE OVER THIS PART OF THE CWA.
MOS GUIDANCE FOR MAX TEMPS LOOKS TO BE IN THE BALLPARK. VALUES ARE
SUPPORTED BY CONDITIONAL CLIMATOLOGY WHICH SUGGESTS A 10-18 DEGREE
WARMUP...AND ALSO DOVETAILS FAIRLY WELL WITH MAX TEMPS DERIVED FROM
THE PROGGED 850MB TEMPS AND THE THINKING THAT AT LEAST PARTIAL
SUNSHINE WILL ALLOW SOME ADDITIONAL WARMING.
TRUETT
.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 350 AM CDT FRI APR 19 2013
(TONIGHT THROUGH SUNDAY NIGHT)
MAIN ISSUE FOR TONIGHT WILL BE WHEN WILL CLOUDS CLEAR OUT AND HOW
COLD WILL IT GET. AS SYSTEM CONTINUES TO LIFT TO NORTHEAST THROUGH
SOUTHERN CANADA TONIGHT...WE CONTINUE TO BE IN WRAP AROUND FLOW WITH
GUSTY WEST TO NORTHWEST WINDS DIMINISHING BY 06Z. BUT WITH SO MUCH
LOW LEVEL MOISTURE DUE TO MAJOR RAINFALL PAST 36 HOURS...NOT SURE
HOW CONFIDENT I AM ABOUT FROST/FREEZE POTENTIAL. BUT WITH STUFF
BUDDING OUT OVER REGION...SKIES CLEARING OUT/WIND DIMINISHING AND LOWS
FORECAST IN THE UPPER 20S TO LOW 30S...WILL ERR ON SIDE OF CAUTION
AND ISSUE A FREEZE WARNING FOR FAR NORTHERN 6 COUNTIES AND FROST
ADVISORY FOR THE REMAINDER OF THE FORECAST AREA FROM 06Z TO 13Z
TONIGHT.
BEYOND THAT QUIET WEATHER IN STORE FOR THE WEEKEND WITH TEMPERATURES
MODERATING THROUGH THE PERIOD. HIGHS ON SATURDAY WILL BE IN THE MID
50S TO LOW 60S. LOWS SATURDAY NIGHT WILL BE WARMER...ONLY IN THE
UPPER 30S TO MID 40S. HIGHS WARMING UP INTO THE MID 60S EVERYWHERE
ON SUNDAY WITH LOWS SUNDAY NIGHT IN THE MID 40S...AHEAD OF NEXT
WEATHER SYSTEM.
(MONDAY THROUGH THURSDAY)
EXTENDED MODELS CONTINUE TO HAVE DIFFERENCES ON STRENGTH AND TIMING
OF NEXT WEATHER SYSTEM THAT WILL BEGIN TO AFFECT THE FORECAST AREA
ON MONDAY. FOR NOW HAVE SHOWERS AND THUNDERSTORMS MOVING INTO FAR
NORTHERN PORTIONS OF FORECAST AREA ON MONDAY. THEN SHOWERS AND
THUNDERSTORMS TO INCREASE IN COVERAGE MONDAY NIGHT THROUGH
TUESDAY...BEFORE TAPERING OFF FROM WEST TO EAST ON TUESDAY NIGHT.
TEMPERATURES TO REMAIN NEAR NORMAL ON MONDAY IN THE MID TO UPPER
60S...THEN DROP OFF INTO THE LOW TO MID 50S BY WEDNESDAY AS SURFACE
RIDGE BUILDS IN. COOL OFF NOT TO LAST LONG AS TEMPERATURES BEGIN TO
MODERATE ON THURSDAY...WARMING UP INTO THE UPPER 50S TO LOW 60S.
BYRD
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 705 AM CDT FRI APR 19 2013
EXTENSIVE AREA OF COLD AIR SC CONTINUES TO BLANKET FA EARLY
TODAY...BUT BACK EDGE OF CLOUD DECK CONTINUES TO PUSH EAST AND IS
NOW APPROXIMATELY 85 MI W OF KCOU. EXPECT THIS EDGE TO CONTINUE
PUSHING EAST...BUT ALSO ANTICIPATE THAT DIURNAL CU WILL BEGIN TO
FORM NO LATER THAN MID MORNING AND WILL AT LEAST PARTIALLY OFFSET
A LINEAR WEST TO EAST CLEARING TREND ACROSS THE AREA.
THEREFORE...EXPECT CURRENT HIGH END MVFR/LOW END VFR OVC TO
GRADUALLY TRANSITION TO A SCT-BKN VFR DECK 4-6KFT BETWEEN MID
MORNING AND EARLY AFTERNOON...WITH ALL CLOUDS DISSIPATING THIS
EVENING WITH LOSS OF HEATING. WEST WINDS WILL REMAIN QUITE
GUSTY...WITH DEEP MIXING ALLOWING GUSTS AROUND 30 KTS. SKIES
SHOULD QUICKLY CLEAR AND WINDS WILL RAPIDLY DIMINISH BY EARLY THIS
EVENING AS DAYTIME HEATING IS LOST.
DUE TO THE WATERLOGGED GROUND...WILL NEED TO KEEP AN EYE ON FOG
POTENTIAL TONIGHT...ESPECIALLY IN LOW LYING AREAS SUCH AS SUS.
SPECIFICS FOR KSTL...CLOUDS AOA 3KFT SHOULD BE THE RULE FOR MUCH
OF THE DAY...ALTHOUGH CERTAINLY EXPECT CURRENT OVC TO TRANSITION
TO A BKN-SCT TYPE COVERAGE BY AROUND MIDDAY. STRONG WEST WINDS
WILL BE GUSTING TO AROUND 30 KTS BY LATE MORNING AND INTO THE
EARLY PART OF THE AFTERNOON. LOSS OF DIURNAL HEATING SHOULD ALLOW
SKIES TO QUICKLY CLEAR AND WINDS TO QUICKLY SUBSIDE DURING THE
EARLY EVENING HOURS.
TRUETT
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...FROST ADVISORY FROM 1 AM TO 8 AM CDT SATURDAY FOR AUDRAIN MO-
BOONE MO-CALLAWAY MO-COLE MO-CRAWFORD MO-FRANKLIN MO-
GASCONADE MO-IRON MO-JEFFERSON MO-LINCOLN MO-MADISON MO-
MONITEAU MO-MONROE MO-MONTGOMERY MO-OSAGE MO-PIKE MO-RALLS
MO-REYNOLDS MO-ST. CHARLES MO-ST. FRANCOIS MO-ST. LOUIS
CITY MO-ST. LOUIS MO-STE. GENEVIEVE MO-WARREN MO-WASHINGTON
MO.
FREEZE WARNING FROM 1 AM TO 8 AM CDT SATURDAY FOR KNOX MO-LEWIS
MO-MARION MO-SHELBY MO.
IL...FROST ADVISORY FROM 1 AM TO 8 AM CDT SATURDAY FOR BOND IL-
CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL-JERSEY IL-
MACOUPIN IL-MADISON IL-MARION IL-MONROE IL-MONTGOMERY IL-
PIKE IL-RANDOLPH IL-ST. CLAIR IL-WASHINGTON IL.
FREEZE WARNING FROM 1 AM TO 8 AM CDT SATURDAY FOR ADAMS IL-BROWN
IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1221 PM EDT FRI APR 19 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE EAST FROM THE GREAT LAKES TODAY AND WILL MOVE
ACROSS THE NORTH COUNTRY TONIGHT...BRINGING GUSTY SOUTHERLY WINDS
AND RAIN SHOWERS AND POSSIBLE THUNDERSTORMS LATE THIS AFTERNOON
AND TONIGHT. MUCH COOLER WEATHER WILL BE OVER THE REGION ON SATURDAY.
A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION SATURDAY NIGHT AND
WILL REMAIN OVER THE NORTH COUNTRY THROUGH MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1221 PM EDT FRIDAY...MINOR UPDATES TO T/TD/MAX T NUMBERS
THROUGH EARLY EVENING BASED OFF CURRENT OBSERVATONAL DATA AND
LATEST LAMP/RAP DATA. OTHERWISE NO OTHER APPRECIABLE ADJUSTMENTS
NEEDED ATTM. PRIOR DISCUSSION FOLLOWS...
A VERY WINDY AND MILD DAY STILL ON TAP WITH MODEST UPDATES TO
TEMPS/WIND/WIND GUSTS AND POPS THROUGH THE EVENING HOURS TO ACCT
FOR CURRENT AND EXPECTED TRENDS. BASED OFF MOST RECENT RAP/NAM12
MIXED LAYER SOUNDINGS AND CURRENT OBSERVATIONAL DATA HAVE GONE
AHEAD AND ISSUED A WIND ADVISORY FROM THE CHAMPLAIN VALLEY WEST
INTO OUR NRN NY COUNTIES THROUGH THIS EVENING FOR
SOUTH/SOUTHWESTERLY GUSTS INTO THE 45 TO 55 MPH RANGE. ALREADY
HAVE RECEIVED ISOLATED TREE/POWER OUTAGE REPORTS EITHER FROM LAST
NIGHT OR THIS MORNING...AND EXPECTED MORE OF THE SAME TODAY/THIS
EVENING AS PRE- FRONTAL P-GRAD REMAINS TIGHT AND PBL DEEPENS (SEE
OUR LATEST REPORTS). STILL EXPECTING THE FRONTAL BOUNDARY TO
ARRIVE INTO OUR FAR WESTERN COUNTIES BY LATE THIS AFTERNOON...AND
INTO VT TOWARD SUNSET. STRONG ANAFRONTAL SIGNATURE WITH THIS
FEATURE WITH PRIMARY RAIN SHIELD BEHIND THE WIND SHIFT.
INDEED...AN INCREDIBLY TIGHT 925 MB THERMAL GRADIENT ALONG THE
FRONT WITH VALUES DROPPING FROM +18C TO +5C IN A MATTER OF 50 NM
OR SO. THIS TYPE OF FORCING MAY LEAD TO SHALLOW CONVECTIVE FINE-
LINE DEVELOPMENT ACROSS OUR NRN NY/CHAMPLAIN VALLEY COUNTIES RIGHT
ALONG THE SFC BOUNDARY BEFORE WEAKENING AS IT PROGRESSES INTO ERN
VT AS SUGGESTED BY THE HRRR DATA. WITH SUCH WIND IN THE
PBL...UPDRAFT STRENGTH AND LIGHTNING THREAT LIKELY MINIMAL...BUT
AN ENHANCED CONVECTIVE WIND THREAT MAY AT LEAST BE PLAUSIBLE
SHOULD SUCH A FEATURE DEVELOP. TIME WILL TELL. OVERALL RAIN
AMOUNTS GENERALLY IN THE 0.33 TO 0.75 INCH RANGE WITH CUSTOMARY
VARIATION...ESPECIALLY GIVEN STRONG FLOW AND LOCALIZED
OROGRAPHICAL EFFECTS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
AS OF 458 AM EDT FRIDAY...THE COLD FRONT WILL MOVE THROUGH THE
REGION TONIGHT. HAVE GONE WITH LIKELY TO CATEGORICAL POPS FOR RAIN
SHOWERS TONIGHT. MUCH COOLER TEMPERATURES WILL BE OVER THE REGION
ON SATURDAY WITH HIGHS FROM THE UPPER 40S TO LOWER 50S. THERE WILL
BE A SLIGHT CHANCE FOR SOME RAIN SHOWERS OVER THE HIGHER
ELEVATIONS OF THE ADIRONDACKS AND GREEN MOUNTAINS ON SATURDAY. A
RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION SATURDAY NIGHT
AND SUNDAY...WITH LOWS SATURDAY NIGHT IN THE TEENS AND 20S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 512 AM EDT FRIDAY...SFC RIDGE NEARBY ON SUNDAY NIGHT INTO
MONDAY AND ASSOCIATED DEEP DRY LAYER WL RESULT IN MAINLY CLR
SKIES. PROGGED 85H TEMPS BTWN -2C AND -4C SUPPORT HIGHS IN THE
M40S NEK/MTNS TO M50S CPV/SLV. STILL PLENTY OF UNCERTAINTY FOR
TUESDAY AND BEYOND WITH REGARDS TO POTENTIAL COASTAL SYSTEM ON
TUESDAY AND ANOTHER GREAT LAKES CUTTER ON THURS. LATEST 00Z ECMWF
SHOWS SFC LOW PRES DEVELOPING ACRS SNE ON TUES...AS 5H S/W ENERGY
TRACKS ACRS OUR FA. ECWMF SHOWS BEST 850 TO 500MB RH JUST TOO OUR
EAST...ALONG WITH NO CLOSED 5H/7H CIRCULATION...THEREFORE FEEL
IMPACT TO OUR CWA WL BE LIMITED. WL CONT TO MENTION LOW CHC POPS.
TEMPS WL BE COOL WITH PROGGED 85H TEMPS NEAR 0C...AND LIMITED
MIXING FROM CLOUDS...THINKING MAINLY 40S EASTERN/CENTRAL VT/MTNS AND
L/M 50S ELSEWHERE. BOTH GFS/ECMWF CONTS TO SUPPORT AN ACTIVE
PATTERN WITH ANOTHER SYSTEM IMPACTING OUR FA LATE WEDS INTO THURS.
STILL SOME UNCERTAINTY WITH REGARDS TO TIMING OF MOISTURE/QPF AND
EXACT STORM TRACK. LATEST TRENDS SHOW SFC LOW PRES TRACKING TO OUR
WEST...WITH GUSTY SOUTHERLY WINDS DEVELOPING ON WEDS AFTN INTO
THURS...VERY SIMILAR TO THE SYSTEM TODAY. GIVEN EXPECTED TRACK TO
OUR WEST...ANTICIPATE OUR CWA WL BE IN THE WARM SECTOR WITH MUCH
ABOVE NORMAL TEMPS POSSIBLE WEDS INTO THURSDAY...ALONG WITH A
BRIEF 3 TO 6 HR WINDOW OF SHOWERS. WL TREND TWD ABOVE NORMAL TEMPS
AND MENTION CHC POPS ATTM. AS THE EVENT BECMG CLOSER...WL FINE
TUNE TEMPS/POP TIMING...ALONG WITH QPF AMOUNTS.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
THROUGH 12Z SATURDAY...GUSTY SOUTHERLY WINDS WL CONT TODAY AT ALL
TAF SITES...ALONG WITH A 3 TO 5 HR WINDOW OF SHOWERS AND POTENTIAL
MVFR CONDITIONS. CRNT SFC ANALYSIS SHOWS A TIGHT PRES GRADIENT
CONTS BTWN SFC LOW PRES OVER THE NORTHERN GREAT LAKES AND HIGH
PRES ACRS THE NORTH ATLANTIC. THIS WL CREATE SFC WIND GUSTS BTWN
30 AND 35 KNTS TODAY...ALONG WITH AREAS OF MODERATE LLVL
TURBULENCE. GIVEN THE LACK OF MIXING AT MPV/RUT HAVE MENTION LLVL
WS THRU 15Z. OTHERWISE...BAND OF RAIN SHOWERS WL IMPACT MSS BTWN
20-24Z TODAY...AND INTO THE CPV BY 00Z...AND EAST AND SOUTH OF
MPV/RUT BY 06Z TONIGHT. EXPECT A 3 TO 5 HR WINDOW OF MODERATE RAIN
WITH MVFR CIGS/VIS LIKELY. A WIND SHIFT TO THE WEST/SOUTHWEST IS
ANTICIPATED BY 06Z BEHIND SFC COLD FRNT. COOLER AND BREEZY
CONDITIONS WL CONT AFT 06Z...WITH MAINLY VFR CONDITIONS.
OUTLOOK 12Z SATURDAY THROUGH TUESDAY...GUSTY WINDS WL SLOWLY
DECREASE ON SATURDAY...WITH SFC HIGH PRES BUILDING INTO OUR TAF
SITES. VFR CONDITIONS WL PREVAIL THRU MONDAY...WITH SOME INCREASE
IN CLOUDS AND CHCS OF PREICP BY MONDAY NIGHT INTO
TUESDAY...ESPECIALLY MPV/RUT.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...WIND ADVISORY UNTIL 11 PM EDT THIS EVENING FOR VTZ001-002-005-
009-011.
NY...WIND ADVISORY UNTIL 11 PM EDT THIS EVENING FOR NYZ026>031-034-
035-087.
&&
$$
SYNOPSIS...WGH
NEAR TERM...JMG
SHORT TERM...WGH
LONG TERM...TABER
AVIATION...TABER
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1016 AM EDT FRI APR 19 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE EAST FROM THE GREAT LAKES TODAY AND WILL MOVE
ACROSS THE NORTH COUNTRY TONIGHT...BRINGING GUSTY SOUTHERLY WINDS
AND RAIN SHOWERS AND POSSIBLE THUNDERSTORMS LATE THIS AFTERNOON
AND TONIGHT. MUCH COOLER WEATHER WILL BE OVER THE REGION ON SATURDAY.
A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION SATURDAY NIGHT AND
WILL REMAIN OVER THE NORTH COUNTRY THROUGH MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1016 AM EDT FRIDAY...A VERY WINDY AND MILD DAY STILL ON TAP
WITH MODEST UPDATES TO TEMPS/WIND/WIND GUSTS AND POPS THROUGH THE
EVENING HOURS TO ACCT FOR CURRENT AND EXPECTED TRENDS. BASED OFF
MOST RECENT RAP/NAM12 MIXED LAYER SOUNDINGS AND CURRENT
OBSERVATIONAL DATA HAVE GONE AHEAD AND ISSUED A WIND ADVISORY FROM
THE CHAMPLAIN VALLEY WEST INTO OUR NRN NY COUNTIES THROUGH THIS
EVENING FOR SOUTH/SOUTHWESTERLY GUSTS INTO THE 45 TO 55 MPH RANGE.
ALREADY HAVE RECEIVED ISOLATED TREE/POWER OUTAGE REPORTS EITHER
FROM LAST NIGHT OR THIS MORNING...AND EXPECTED MORE OF THE SAME
TODAY/THIS EVENING AS PRE- FRONTAL P-GRAD REMAINS TIGHT AND PBL
DEEPENS (SEE OUR LATEST REPORTS). STILL EXPECTING THE FRONTAL
BOUNDARY TO ARRIVE INTO OUR FAR WESTERN COUNTIES BY LATE THIS
AFTERNOON...AND INTO VT TOWARD SUNSET. STRONG ANAFRONTAL SIGNATURE
WITH THIS FEATURE WITH PRIMARY RAIN SHIELD BEHIND THE WIND SHIFT.
INDEED...AN INCREDIBLY TIGHT 925 MB THERMAL GRADIENT ALONG THE
FRONT WITH VALUES DROPPING FROM +18C TO +5C IN A MATTER OF 50 NM
OR SO. THIS TYPE OF FORCING MAY LEAD TO SHALLOW CONVECTIVE FINE-
LINE DEVELOPMENT ACROSS OUR NRN NY/CHAMPLAIN VALLEY COUNTIES RIGHT
ALONG THE SFC BOUNDARY BEFORE WEAKENING AS IT PROGRESSES INTO ERN
VT AS SUGGESTED BY THE HRRR DATA. WITH SUCH WIND IN THE
PBL...UPDRAFT STRENGTH AND LIGHTNING THREAT LIKELY MINIMAL...BUT
AN ENHANCED CONVECTIVE WIND THREAT MAY AT LEAST BE PLAUSIBLE
SHOULD SUCH A FEATURE DEVELOP. TIME WILL TELL. OVERALL RAIN
AMOUNTS GENERALLY IN THE 0.33 TO 0.75 INCH RANGE WITH CUSTOMARY
VARIATION...ESPECIALLY GIVEN STRONG FLOW AND LOCALIZED
OROGRAPHICAL EFFECTS. PRIOR DISCUSSION FOLLOWS...
SURFACE PRESSURE GRADIENT WILL REMAIN TIGHT ACROSS THE REGION
TODAY...WITH SOUTHERLY SURFACE WIND GUSTS UP TO 45 MPH POSSIBLE
THIS AFTERNOON. THIS IS JUST BELOW WIND ADVISORY CRITERIA.
EXPECTING A MAINLY DRY DAY TODAY WITH SOME PARTLY SUNNY
SKIES...AND TEMPERATURES CLIMBING INTO THE LOWER 70S. THE BEST
CHANCE FOR RAIN SHOWERS WILL BE LATE THIS AFTERNOON ACROSS THE
SAINT LAWRENCE VALLEY AND THE ADIRONDACKS IN NORTHERN NEW YORK
...ALONG WITH A SLIGHT CHANCE FOR SOME THUNDERSTORMS. THE SHOWER
ACTIVITY WILL BE MAINLY BEHIND THE COLD FRONT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
AS OF 458 AM EDT FRIDAY...THE COLD FRONT WILL MOVE THROUGH THE
REGION TONIGHT. HAVE GONE WITH LIKELY TO CATEGORICAL POPS FOR RAIN
SHOWERS TONIGHT. MUCH COOLER TEMPERATURES WILL BE OVER THE REGION
ON SATURDAY WITH HIGHS FROM THE UPPER 40S TO LOWER 50S. THERE WILL
BE A SLIGHT CHANCE FOR SOME RAIN SHOWERS OVER THE HIGHER
ELEVATIONS OF THE ADIRONDACKS AND GREEN MOUNTAINS ON SATURDAY. A
RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION SATURDAY NIGHT
AND SUNDAY...WITH LOWS SATURDAY NIGHT IN THE TEENS AND 20S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 512 AM EDT FRIDAY...SFC RIDGE NEARBY ON SUNDAY NIGHT INTO
MONDAY AND ASSOCIATED DEEP DRY LAYER WL RESULT IN MAINLY CLR
SKIES. PROGGED 85H TEMPS BTWN -2C AND -4C SUPPORT HIGHS IN THE
M40S NEK/MTNS TO M50S CPV/SLV. STILL PLENTY OF UNCERTAINTY FOR
TUESDAY AND BEYOND WITH REGARDS TO POTENTIAL COASTAL SYSTEM ON
TUESDAY AND ANOTHER GREAT LAKES CUTTER ON THURS. LATEST 00Z ECMWF
SHOWS SFC LOW PRES DEVELOPING ACRS SNE ON TUES...AS 5H S/W ENERGY
TRACKS ACRS OUR FA. ECWMF SHOWS BEST 850 TO 500MB RH JUST TOO OUR
EAST...ALONG WITH NO CLOSED 5H/7H CIRCULATION...THEREFORE FEEL
IMPACT TO OUR CWA WL BE LIMITED. WL CONT TO MENTION LOW CHC POPS.
TEMPS WL BE COOL WITH PROGGED 85H TEMPS NEAR 0C...AND LIMITED
MIXING FROM CLOUDS...THINKING MAINLY 40S EASTERN/CENTRAL VT/MTNS AND
L/M 50S ELSEWHERE. BOTH GFS/ECMWF CONTS TO SUPPORT AN ACTIVE
PATTERN WITH ANOTHER SYSTEM IMPACTING OUR FA LATE WEDS INTO THURS.
STILL SOME UNCERTAINTY WITH REGARDS TO TIMING OF MOISTURE/QPF AND
EXACT STORM TRACK. LATEST TRENDS SHOW SFC LOW PRES TRACKING TO OUR
WEST...WITH GUSTY SOUTHERLY WINDS DEVELOPING ON WEDS AFTN INTO
THURS...VERY SIMILAR TO THE SYSTEM TODAY. GIVEN EXPECTED TRACK TO
OUR WEST...ANTICIPATE OUR CWA WL BE IN THE WARM SECTOR WITH MUCH
ABOVE NORMAL TEMPS POSSIBLE WEDS INTO THURSDAY...ALONG WITH A
BRIEF 3 TO 6 HR WINDOW OF SHOWERS. WL TREND TWD ABOVE NORMAL TEMPS
AND MENTION CHC POPS ATTM. AS THE EVENT BECMG CLOSER...WL FINE
TUNE TEMPS/POP TIMING...ALONG WITH QPF AMOUNTS.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
THROUGH 12Z SATURDAY...GUSTY SOUTHERLY WINDS WL CONT TODAY AT ALL
TAF SITES...ALONG WITH A 3 TO 5 HR WINDOW OF SHOWERS AND POTENTIAL
MVFR CONDITIONS. CRNT SFC ANALYSIS SHOWS A TIGHT PRES GRADIENT
CONTS BTWN SFC LOW PRES OVER THE NORTHERN GREAT LAKES AND HIGH
PRES ACRS THE NORTH ATLANTIC. THIS WL CREATE SFC WIND GUSTS BTWN
30 AND 35 KNTS TODAY...ALONG WITH AREAS OF MODERATE LLVL
TURBULENCE. GIVEN THE LACK OF MIXING AT MPV/RUT HAVE MENTION LLVL
WS THRU 15Z. OTHERWISE...BAND OF RAIN SHOWERS WL IMPACT MSS BTWN
20-24Z TODAY...AND INTO THE CPV BY 00Z...AND EAST AND SOUTH OF
MPV/RUT BY 06Z TONIGHT. EXPECT A 3 TO 5 HR WINDOW OF MODERATE RAIN
WITH MVFR CIGS/VIS LIKELY. A WIND SHIFT TO THE WEST/SOUTHWEST IS
ANTICIPATED BY 06Z BEHIND SFC COLD FRNT. COOLER AND BREEZY
CONDITIONS WL CONT AFT 06Z...WITH MAINLY VFR CONDITIONS.
OUTLOOK 12Z SATURDAY THROUGH TUESDAY...GUSTY WINDS WL SLOWLY
DECREASE ON SATURDAY...WITH SFC HIGH PRES BUILDING INTO OUR TAF
SITES. VFR CONDITIONS WL PREVAIL THRU MONDAY...WITH SOME INCREASE
IN CLOUDS AND CHCS OF PREICP BY MONDAY NIGHT INTO
TUESDAY...ESPECIALLY MPV/RUT.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...WIND ADVISORY UNTIL 11 PM EDT THIS EVENING FOR VTZ001-002-005-
009-011.
NY...WIND ADVISORY UNTIL 11 PM EDT THIS EVENING FOR NYZ026>031-034-
035-087.
&&
$$
SYNOPSIS...WGH
NEAR TERM...JMG/WGH
SHORT TERM...WGH
LONG TERM...TABER
AVIATION...TABER
AREA FORECAST DISCUSSION
NWS RALEIGH NC
111 AM EDT FRI APR 19 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL MOVE ACROSS CENTRAL NORTH CAROLINA THIS
AFTERNOON AND EVENING...BRINGING WITH IT HEAVY RAIN AND THE CHANCE
FOR SEVERE THUNDERSTORMS. BEHIND THE FRONT...COOLER AND DRIER
CONDITIONS WILL MOVE IN FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 1030 AM FRIDAY...
OBSERVATIONS SHOW THE INGREDIENTS COMING TOGETHER FOR A POTENTIALLY
SEVERE THUNDERSTORM EVENT ACROSS CENTRAL NORTH CAROLINA LATER THIS
AFTERNOON AND INTO THE EVENING. AIDED BY THE DEVELOPMENT OF A 50
KNOT LOW LEVEL GET AT 850 THROUGH 700 MB...MOISTURE HAS BEGUN TO
INCREASE ACROSS THE AREA AND TEMPERATURES RISING INTO THE LOW TO MID
70S HAS BEGUN TO ERODE ANY LEFTOVER CIN FROM THE OVERNIGHT HOURS AND
INSTABILITY IS BEGINNING TO INCREASE. RADAR TRENDS SHOW SOME
CONVECTIVE DEVELOPMENT ALONG THE COASTAL AREAS AS WELL AS SOME
SMALLER SHOWERS BREAKING OUT BACK ACROSS THE WESTERN PIEDMONT IN
ADVANCE OF THE MAIN LINE OF SHOWERS AND THUNDERSTORMS WHICH IS
CURRENTLY TREKKING THROUGH THE MOUNTAINS OF EASTERN TENNESSEE.
COMPARED TO HIGH RESOLUTION MODELS IT APPEARS THE ACTUAL STORM
SYSTEM MAY BE AN HOUR OR TWO AHEAD OF SCHEDULE. FOR THE TIMING
ACROSS THE CWA WILL MOVE UP THE TIME FRAME TO NEAR 21Z (5 PM) IN THE
TRIAD...00Z (8 PM) FOR THE TRIANGLE AND 03Z (11 PM) FOR THE I-95
CORRIDOR. DAMAGING WINDS AND HEAVY RAIN ARE STILL THE PRIMARY
THREATS ASSOCIATED WITH THIS SYSTEM ALTHOUGH SMALL HAIL AND ISOLATED
TORNADOES WILL STILL BE POSSIBLE...ESPECIALLY IN THE SOUTH AND EAST
WHERE A LOOK AT RAP SOUNDINGS THROUGH BUFKIT SHOW INCREASED 0-1 KM
HELICITY. THIS WOULD ESPECIALLY BE A CONCERN IN ANY DISCREET CELLS
THAT DEVELOP OUT AHEAD OF THE LINE OF THUNDERSTORMS. GOES VISIBLE
SATELLITE IMAGERY SHOWS SOME BREAKS IN THE CLOUD COVER OVER SOUTH
CAROLINA BEGINNING TO ADVANCE NORTHWARD INDICATING THAT A GREATER
DIFFERENTIAL HEATING BOUNDARY MAY SET UP OVER THE CWA WITH HIGHER
MAX TEMPS IN THE SOUTH AND EAST (MIDDLE 80S) AS COMPARED TO THE
TRIAD (UPPER 70S). THIS BOUNDARY COULD BECOME A FOCUS FOR CONVECTION
LATER ON THIS EVENING. ONCE THE FRONT CLEARS TO THE EAST EXPECT
LINGERING ANAFRONTAL RAIN TO CONTINUE FOR SEVERAL HOURS. -ELLIS
OVERNIGHT LOWS ON FRIDAY NIGHT WILL BE DEPENDENT ON THE TIMING OF
THE EXITING PRECIP AND COMMENCEMENT OF COLD AIR ADVECTION. AT THIS
TIME...IT APPEARS PRECIP SHOULD CLEAR OUT OF AT LEAST THE WESTERN
PORTIONS OF THE FORECAST AREA BEFORE DAYBREAK AND THEREFORE AM
EXPECTING TEMPS TO RANGE FROM THE UPPER 40S/LOWER 50S ACROSS THE
WEST TO MID/UPPER 50S FURTHER EAST. CONDITIONS WILL IMPROVE
THROUGHOUT THE DAY ON SATURDAY AND WITH COLD AIR ADVECTION
PERSISTING...HIGHS SHOULD GENERALLY BE IN THE MID/UPPER 60S.-KRR
&&
.SHORT TERM /SATURDAY NIGHT AND SUNDAY/...
AS OF 250 AM FRIDAY...
CANADIAN SURFACE HIGH OVER THE UPPER GREAT LAKES WILL STRENGTHEN TO
+1040MB AS IT BUILDS EASTWARD...REACHING THE NEW ENGLAND COAST BY
SUNDAY NIGHT. THIS WILL KEEP IT SEASONABLY COOL AND DRY TO CLOSE THE
WEEKEND WITH LOW-LEVEL THICKNESSES A GOOD 20 TO 25 METERS BELOW
NORMAL WHICH SHOULD TRANSLATE INTO TEMPERATURES A GOOD 10 DEGREES
BELOW NORMAL. EARLY MORNING RISERS WILL NEED A JACKET SUNDAY MORNING
WITH MIN TEMPS 40 TO 45. HIGHS 60 TO 65 WITH BREEZY NELY WINDS
DEVELOPING BY THE AFTERNOON WITH COMPRESSION OF PRESSURE GRADIENT AS
OFFSHORE FRONTAL ZONE BEGINS TO SHARPEN UP.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 250 AM FRIDAY...
...BELOW NORMAL TEMPERATURES NEXT WEEK...
A WEAK MOISTURE DEPRIVED UPPER LEVEL DISTURBANCE IN ADVANCE OF A
MORE SIGNIFICANT NORTHERN STREAM TROUGH WILL QUIETLY MOVE
EASTWARD ACROSS SOUTHERN PLAINS/LOWER MS VALLEY SATURDAY NIGHT
THROUGH SUNDAY. BUT AS THE UPPER DISTURBANCE CROSSES THE SOUTHERN
APPALACHIANS AND MOVES OVER THE CAROLINAS SUNDAY NIGHT/MONDAY...WEAK
CYCLOGENESIS ALONG AN OLD BAROCLINIC FRONTAL ZONE SITTING OFF THE
SOUTHEAST COAST WILL BRING RENEWED VIGOR TO THE UPPER WAVE. RECENT
MODEL RUNS HAVE SHIFTED SLIGHTLY EASTWARD...KEEPING THE BULK OF THE
OVERRUNNING PRECIP ALONG THE IMMEDIATE COAST. WILL CONTINUE TO
MONITOR THIS SYSTEM...ESPECIALLY FOR ANY WESTWARD/INLAND TREND AS
ANY PRECIP FALLING INTO THE WEDGE OF STRONG HIGH PRESSURE EXTENDING
DOWN THE EASTERN SLOPES OF THE APPALACHIANS WILL RESULT IN A STRONG
CAD EVENT FOR MONDAY. FOR NOW WILL GO WITH JUST SLIGHT CHANCE POPS
IN THE EAST...KEEPING THE WESTERN TWO-THIRDS OF THE FORECAST AREA
DRY. TEMPERATURES MONDAY WILL NOT BE MUCH DIFFERENT THAN FROM SUNDAY
WITH LOWS MONDAY MORNING IN THE LOWER TO MID 40S. HIGHS IN THE
LOWER 60S...BUT COULD END UP SIGNIFICANTLY COOLER IF MODELS TREND
WETTER WITH FUTURE RUNS.
THE AFOREMENTIONED NORTHERN STREAM TROUGH AND ATTENDANT SFC COLD
FRONT WILL APPROACH THE AREA FROM THE WEST WEDNESDAY NIGHT/THURSDAY
BRINGING WIDESPREAD SHOWERS TO THE AREA WITH PERHAPS A CHANCE OF
THUNDER. TEMPERATURES WILL REBOUND BACK INTO THE 70S AHEAD OF THE
FRONT ON WEDNESDAY...AND THEN FALLING BACK TO BELOW NORMAL BEHIND
THE FRONTAL PASSAGE TO CLOSE THE WEEK.
&&
.AVIATION /18Z FRIDAY THROUGH TUESDAY/...
AS OF 110 PM FRIDAY...
24 HOUR TAF PERIOD: VERY HIGH CONFIDENCE OF SUB VFR CONDITIONS THIS
EVENING AS A COLD FRONT CROSSES THE AREA. PRIOR TO FRONTAL PASSAGE
MVFR CONDITIONS WILL LIFT OUT TO VFR FOR A PERIOD OF SEVERAL HOURS.
AHEAD OF THE FRONT EXPECT BREEZY CONDITIONS TO CONTINUE AS
OBSERVATIONS HAVE SHOW WINDS OF 15-20 KNOTS SUSTAINED GUSTING TO
NEAR 30 KNOTS. EXPECT A WEST TO EAST ADVANCE OF DETERIORATING
CONDITIONS WITH KINT AND KGSO AFFECTED BY THE FRONT BETWEEN 20Z AND
0Z. KRDU AND KFAY WILL SEE STORMS IN THE 22Z TO 2Z TIMEFRAME AND
FURTHER EAST AT KRWI BETWEEN 0Z AND 4Z. WIND GUSTS TO 40 KNOTS AND
POTENTIALLY HIGHER ARE POSSIBLE WITHIN STORMS. AFTER FRONTAL PASSAGE
EXPECT STRATIFORM RAIN TO CONTINUE FOR SEVERAL HOURS AT ALL SIGHTS
WITH CONDITIONS DETERIORATING AGAIN TO AT LEAST MVFR IF NOT LOWER.
RAIN SHOULD MOVE OUT BY SATURDAY MORNING AND CONDITIONS WILL RETURN
TO VFR. WINDS WILL BECOME NORTHWESTERLY AFTER FRONTAL PASSAGE NEAR
10 KNOTS.
LONG TERM: SPORADIC SUB-VFR EPISODES ARE POSSIBLE SUNDAY NIGHT
THROUGH WEDNESDAY. OTHERWISE VFR CONDITIONS ARE EXPECTED.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...ELLIS/KRR
SHORT TERM...CBL
LONG TERM...CBL
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1005 AM CDT FRI APR 19 2013
.UPDATE...
ISSUED AT 1005 AM CDT FRI APR 19 2013
MAIN FORECAST CONCERN FOR THE UPDATE THIS MORNING IS SKY COVER OR
LACK THEREOF...AND PRECIPITATION CHANCES. HIGH PRESSURE FROM
MANITOBA AND SASKATCHEWAN EXTENDS SOUTH INTO NORTH DAKOTA. THIS
HAS RESULTED IN MAINLY CLEAR SKIES WESTERN AND CENTRAL NORTH
DAKOTA...EXCEPT FOR THE FAR SOUTHWEST CORNER. A SHORTWAVE THAT
DROPPED THROUGH WESTERN NORTH DAKOTA DID PRODUCE SOME LIGHT SNOW
OVER THE SOUTHWEST. THERE ARE SOME LINGERING LIGHT SNOW SHOWERS
FROM BEACH TO BOWMAN...HOWEVER EXPECT THESE TO DISSIPATE DURING
THE MORNING. OTHERWISE...IT SHOULD REMAIN SUNNY ACROSS CENTRAL
NORTH DAKOTA TODAY...WITH INCREASING CLOUDS WEST THIS AFTERNOON.
WILL TAKE ANOTHER LOOK AT TEMPERATURES LATE MORNING OR EARLY
AFTERNOON.
UPDATE ISSUED AT 701 AM CDT FRI APR 19 2013
HIGH PRESSURE BUILDING INTO THE REGION HAS SCOURED OUT MUCH OF THE
LOW-LEVEL MOISTURE ACROSS CENTRAL NORTH DAKOTA. AS A
RESULT...DECREASED THE FIRST PERIOD SKY COVER ACROSS THE
AFOREMENTIONED REGION.
A 75+ KT 500MB JET STREAK DIVING SOUTH OVER WESTERN NORTH DAKOTA
HAS GENERATED VERY NARROW SNOW BANDS WEST THIS MORNING. AS A
RESULT...SHIFTED ISOLATED POPS A LITTLE FARTHER WEST BASED ON
CURRENT OBS/TRENDS. THIS JET STREAK SHOULD BE OVER SOUTH DAKOTA BY
MID TO LATE MORNING TAKING ANY PRECIP CHANCES WITH IT.
THE REMAINED GRIDDED WEATHER ELEMENTS ARE IN GOOD SHAPE. THE
UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT FRI APR 19 2013
THE FORECAST HIGHLIGHT FOR THE SHORT TERM PERIOD IS THE CONTINUED
CHANCES FOR LIGHT PRECIPITATION.
CURRENTLY...AN UPPER LEVEL SHORTWAVE IS DIVING SOUTHEAST OUT OF
CANADA...WHILE AN AREA OF WEAK LOW PRESSURE WAS LOCATED OVER
NORTHEASTERN MONTANA...WITH AN ASSOCIATED WARM FRONT DRAPED ACROSS
WESTERN NORTH DAKOTA AND A TRAILING COLD FRONT OVER NORTHERN
MONTANA. THE FOCUS FOR THE MID LEVEL CLOUD SHIELD AND LIGHT
PRECIPITATION THIS MORNING IS IN THE VICINITY OF THE WARM FRONT.
LATEST RADAR IMAGERY CONTINUES TO SHOW SCATTERED LIGHT RETURNS
OVER THE WEST...WHILE SURFACE OBSERVATIONS HAVE SHOWN BRIEF
PERIODS OF LIGHT SNOW. THE 00Z NAM/07Z RAP HAS THIS AREA OF LIGHT
SNOW DISSIPATING IN INTENSITY THIS MORNING...AND THUS HAVE
DECREASED POPS ACROSS THE CENTRAL PART OF THE STATE THIS MORNING.
A BRIEF LULL IN THE LIGHT PRECIPITATION WILL BE SEEN TODAY BEFORE
THE NEXT UPPER LEVEL WAVE AND ASSOCIATED SURFACE LOW PRESSURE
PROGRESSES SOUTHWARD TONIGHT. THE 00Z SUITE OF MODELS ARE IN GOOD
AGREEMENT THAT LIGHT PRECIPITATION IN THE FORM OF A LIGHT WINTRY
MIX AND LIGHT SNOW WILL MOVE INTO THE WEST BEFORE MIDNIGHT...AND
THEN SPREAD INTO THE CENTRAL AFTER MIDNIGHT.
MEANWHILE...THE CONTINUED THEME OF BELOW NORMAL TEMPERATURES WILL
CONTINUE. HIGHS WILL BE 10 TO 20 DEGREES BELOW NORMAL...AS HIGHS
WILL WARM ONLY INTO THE LOWER 30S...EXCEPT THE SOUTHWEST WHERE MID
TO UPPER 30S ARE POSSIBLE. FOR OVERNIGHT LOWS...TEMPERATURES WILL RANGE
FROM THE LOWER TEENS IN THE JAMES RIVER VALLEY TO THE UPPER 20S
FAR SOUTHWEST. A RECORD LOW TEMPERATURE FOR JAMESTOWN MAY BE IN
JEOPARDY TONIGHT...AS THE OVERNIGHT LOW IS FORECAST TO BE 12
DEGREES AND THE RECORD LOW IS 14 DEGREES SET IN 1966.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 334 AM CDT FRI APR 19 2013
THE MEDIUM RANGE MODELS CONTINUE TO PROG A WET WEEKEND FOR WESTERN
AND CENTRAL NORTH DAKOTA. A WARM FRONT PUSHING ACROSS THE REGION
WILL GENERATE CHANCE POPS SATURDAY. THE PRECIP TYPE IS EXPECTED TO
GENERALLY BE A WINTRY MIX...WITH LIGHT RAIN POSSIBLE WEST WHERE
THE WARMEST TEMPERATURES ALOFT WILL RESIDE.
AS THE WARM FRONT SHIFTS EAST SATURDAY NIGHT...A COLD FRONT WILL
ENTER WESTERN NORTH DAKOTA AFTER MIDNIGHT. THE COLD FRONT WILL
GENERATE A CHANCE OF A WINTRY MIX NORTH OF I-94 AS IT PUSHES EAST
ACROSS THE REGION SUNDAY. AREAS SOUTH OF I-94 ARE EXPECTED TO SEE
A CHANCE OF LIGHT RAIN SUNDAY. SNOW TOTALS WILL BE IN THE 1-2 INCH
RANGE NORTH...WITH MUCH LIGHTER AMOUNTS EXPECTED SOUTH AND WEST.
A DRYING/WARMING TREND IS EXPECTED MONDAY THROUGH THE END OF THE
PERIOD. HOWEVER...THE LATEST MEDIUM RANGE MODEL GUIDANCE NOW PROGS
A WEAK COLD FRONT TO PUSH THROUGH THE REGION WEDNESDAY. THIS
FEATURE IS EXPECTED TO GENERATE A SLIGHT CHANCE OF LIGHT RAIN
MIXED WITH SLEET WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 1005 AM CDT FRI APR 19 2013
HIGH PRESSURE OVER THE AREA WILL PRODUCE VFR CONDITIONS EXPECTED
AT ALL TAF SITES THROUGH 00Z SATURDAY. A SYSTEM APPROACHING FROM
THE WEST WILL BRING LOWERING CEILINGS AND A CHANCE OF
PRECIPITATION TO KISN AND KDIK BETWEEN 00-06Z SATURDAY AND KMOT
AND KBIS BETWEEN 06-12Z SATURDAY. SOUTHEAST FLOW EXPECTED AT KISN
AND KDIK. LIGHT NORTH FLOW AT KBIS...KMOT AND KJMS WILL SHIFT
SOUTHEAST THIS AFTERNOON INTO EARLY THIS EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...LTH
LONG TERM...TM
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1206 PM CDT FRI APR 19 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 255 PM CDT THU APR 18 2013
LATEST WATER VAPOR SATELLITE IMAGERY PLACED A SHORTWAVE TROUGH OVER
THE REGION...WITH TRENDS DRIVING IT EAST/NORTHEAST. GOOD MID LEVEL
DRY PUNCH ALSO INDICATED...WHICH SHOWS UP IN THE RAP BUFKIT
SOUNDINGS. THIS HAS RESULTED IN THE LOSS OF ICE IN SOME OF THE
CLOUD...AND MOSTLY AREAS OF DRIZZLE AHEAD OF TROUGH/UPPER LEVEL LOW.
DEPENDING ON SFC TEMPS...THERE COULD BE SOME PATCHY FREEZING
DRIZZLE. WEST-EAST RUNNING X-SECTION AND BUFKIT SOUNDINGS DO POINT
TO A RETURN OF THE ICE QUICKLY EARLY THIS MORNING...AND THUS EITHER
SNOW OR RAIN. GIVEN THE MOVEMENT OF THE SYSTEM...THE BETTER CHANCES
FOR ACCUMULATING PCPN WILL BE ACROSS THE NORTH...AND MOSTLY THIS
MORNING.
FOR THE AFTERNOON...RAP SOUNDINGS BUILD SOME SHALLOW NEAR SFC
INSTABILITY...UP TO AROUND 800 MB. 1000-850 MB LAPSE RATES ARE
AROUND 8.5 C/KM. ENOUGH LOW LEVEL SATURATION THAT THIS INSTABILITY
SHOULD RESULT IN SCT/WIDESPREAD SHOWERS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 255 AM CDT FRI APR 19 2013
RELATIVELY STRONG 925-850 MB WARM AIR ADVECTION AND ISENTROPIC
UPGLIDE ON THE 280-290 K SFCS SLATED TO MOVE ACROSS THE FORECAST
AREA BETWEEN 06Z SUN - 00Z MON. THE LOW LEVEL THERMODYNAMIC FORCING
IS AHEAD OF A SHORTWAVE TROUGH SLATED TO DROP SOUTHEAST OVER THE
NORTHERN PLAINS SUN AFTERNOON...AND BE A PLAYER IN PCPN CHANCES FOR
THE REGION FOR THE EARLY PART OF THE NEW WORK WEEK. A FEW PIECES OF
UPPER LEVEL ENERGY AHEAD OF THE TROUGH...WHICH WOULD ADD TO THE
FORCING MIX FOR SUN. WEST-EAST RUNNING X-SECTION POINTS TO
INCREASING SATURATION BY 06Z SUN...DEEP ENOUGH AND COLD ENOUGH FOR
THERE TO BE ICE IN THE CLOUD. PRETTY GOOD CHANCE FOR SOME PCPN WITH
THE LOW LEVEL FORCING...WITH A SNOW/RAIN MIX INITIALLY CHANGING OVER
TO RAIN DURING THE DAY SUNDAY. A HINT OF INSTABILITY IN NAM BUFKIT
SOUNDINGS...BUT NOT MUCH/IF ANY IN THE GFS. WILL KEEP THUNDER
MENTION OUT OF THE FORECAST FOR NOW.
THE TROUGH/S SFC LOW/COLD FRONT SWING IN SUN NIGHT. GFS AND NAM AT
ODDS WITH THE TIMING...WITH THE 19.00Z NAM BRINGING THE FRONT TO THE
MISSISSIPPI RIVER AROUND 03Z MON...WITH THE GFS HOLDING OFF UNTIL
CLOSER TO 12Z MON. THE EC AND GEM ARE CLOSER TO THE GFS. WILL LIKELY
LEAN THIS WAY FOR TIMING. WITH SOME LOW LEVEL MOISTURE RETURN AHEAD
OF THE FRONT...IT WILL SERVE AS ANOTHER FOCUS FOR PCPN GENERATION.
THE GFS AND EC SWING BITS OF UPPER LEVEL ENERGY ACROSS THE REGION
SUN NIGHT-TUE NIGHT...AHEAD OF AN UPPER LEVEL TROUGH WHICH MOVES
OVER THE UPPER MISSISSIPPI RIVER VALLEY TUE NIGHT. THE UPPER LEVEL
FORCING WILL INTERACT WITH A SLOW MOVING NORTH-SOUTH RUNNING FRONTAL
BOUNDARY TO PRODUCE AREAS OF PCPN. MOST WOULD FALL AS RAIN...BUT
SOME MIX WITH AND THEN CHANGE OVER TO SNOW AS THE TROUGH EXITS LATE
TUE NIGHT IS LIKELY.
A BRIEF BREAK ON WED AS HIGH PRESSURE BUILDS IN...BUT IT JUST AS
QUICKLY EXITS SOUTHEAST ALLOWING FOR ANOTHER UPPER LEVEL SHORTWAVE
TROUGH TO DROP IN FROM THE NORTHWEST. GFS/EC BOTH IN AGREEMENT WITH
SPINNING THIS FEATURE ACROSS THE REGION WED NIGHT-THU...WITH MORE
LIGHT PCPN CHANCES RESULTING. MOSTLY RAIN...BUT THERE WOULD BE SOME
SNOW CHANCES TOO.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1206 PM CDT FRI APR 19 2013
CYCLONIC FLOW AROUND THE SURFACE LOW OVER LAKE SUPERIOR CONTINUES
TO GENERATE WIDESPREAD CLOUDS AND SOME SNOW SHOWERS ACROSS THE
AREA. EXPECT THIS TREND TO CONTINUE FOR THE REMAINDER OF THE
AFTERNOON INTO THE EVENING. THE CYCLONIC FLOW AND LOW LEVEL
INSTABILITY SHOULD WEAKEN ENOUGH BY MID EVENING TO ALLOW THE
SHOWERS TO DISSIPATE WITH THE WINDS DIMINISHING AS WELL. UNTIL
THIS HAPPENS...CEILINGS AND VISIBILITY EXPECTED TO PRIMARILY BE
VFR ALTHOUGH THERE WILL BE SOME SHORT PERIODS WHEN A SNOW SHOWER
COULD REDUCE THE VISIBILITY AND CEILINGS TO MVFR. BACK EDGE OF THE
CLOUDS ACROSS NORTHWEST MINNESOTA HAS BEEN MOVING STEADILY
SOUTHEAST AND EXTRAPOLATION OF THIS TIMING WOULD BRING THE
CLEARING INTO KRST AROUND 04Z OR SO AND KLSE AROUND 07Z. THIS
TREND WAS ALREADY IN THE PREVIOUS FORECAST BUT JUST MOVED THE
TIMING UP AT KRST A LITTLE BIT. SKIES SHOULD THEN GO CLEAR
OVERNIGHT WITH SOME DIURNAL CUMULUS EXPECTED TO FORM LATE SATURDAY
MORNING. NOT ENOUGH OF A CHANGE IN THE FORECAST TO INCLUDE THESE
TRENDS AT THIS TIME.
&&
.HYDROLOGY...
ISSUED AT 255 AM CDT FRI APR 19 2013
FLOODING IS CURRENTLY OCCURRING ALONG PORTIONS OF THE BLACK AND
TREMPEALEAU RIVERS. RECENT RAINFALL WILL KEEP THOSE RIVERS ABOVE
FLOOD STAGE INTO THE EARLY WEEKEND.
WET CONDITIONS WILL PERSIST INTO THE EARLY PART OF THE NEW WORK
WEEK...BUT SIGNIFICANT ACCUMULATIONS ARE NOT EXPECTED THROUGH AT
LEAST MONDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04
HYDROLOGY....BOYNE/RIECK