Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/05/13
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1128 AM MDT WED APR 3 2013
.UPDATE...
ISSUED AT 655 AM MDT WED APR 3 2013
UPDATED FORECAST TO REFLECT CURRENT CONDITIONS. REMOVED
DRIZZLE/FOG FROM SOUTHERN I-25 CORRIDOR AS VISIBILITY HAS BEEN
IMPROVING MOST AREAS. STILL SOME DENSE FOG AND PATCHY FREEZING
DRIZZLE ACROSS EL PASO COUNTY THROUGH MID-MRNG AS WINDS HAVE YET
TO GO NORTHERLY. ALSO ADDED A COUPLE HOURS OF LIGHT SNOW TO SAN
LUIS VALLEY...WHERE ALAMOSA HAS BEEN REPORTING SNOW THE PAST HOUR.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM MDT WED APR 3 2013
UPPER LOW GRADUALLY SLIPPING EASTWARD ACROSS THE STATE EARLY THIS
MORNING...AND SHOULD MOVE INTO THE SOUTHERN PLAINS BY THIS
EVENING. STILL SOME RESIDUAL -SHRA/-SHSN/-FZDZ ACROSS THE AREA
THIS MORNING...THOUGH RADAR TRENDS SUGGEST GRADUALLY DECREASING
COVERAGE AND INTENSITY SINCE 09Z. WILL HOLD ON TO SOME LIGHT
PRECIP THROUGH THE MORNING MOST AREAS...GRADUALLY ENDING FROM NW
TO SE BY MIDDAY. MAY SEE A FEW SHOWERS REFIRE OVER THE MTS THIS
AFTERNOON AS LAPSE RATES REMAIN FAIRLY STEEP...THOUGH PRECIP WILL
BE VERY LIGHT. PERSISTENT -FZDZ AND FZFG OVER EL PASO COUNTY MAY
LINGER THROUGH LATE MORNING...AS LATEST HRRR KEEPS WEAK SOUTHEAST
WIND IN PLACE UNTIL 17Z. STILL THINK N-NW FLOW WILL DEVELOP THIS
AFTERNOON AND GRADUALLY REMOVE ANY REMNANTS OF CLOUDS/FOG...THOUGH
FAR SOUTHEAST PLAINS MAY HAVE TO WAIT UNTIL VERY LATE AFTERNOON TO
SEE ANY SUN. WILL CONTINUE WITH REASONABLY MILD MAX TEMPS MOST
LOCATIONS...THOUGH KEPT AREAS AROUND SPRINGFIELD COLDER THAN
GUIDANCE DUE TO LINGERING CLOUDS. OVERNIGHT...WILL END PRECIP
QUICKLY IN THE EVENING WITH LOSS OF HEATING...LEADING TO A MOSTLY
CLEAR AND SEASONABLY COOL NIGHT MOST AREAS UNDER WEAK NORTHWEST
FLOW.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 352 AM MDT WED APR 3 2013
...SIGNIFICANT STORM POSSIBLE EARLY NEXT WEEK...
LATTER HALF OF THIS WEEK LOOKS QUITE PLEASANT AS A TRANSITORY RIDGE
CROSSES OUR AREA. THURSDAY MAY BE THE NICEST DAY...WITH DRY AND CLEAR
CONDITIONS EXPECTED AREA-WIDE. WINDS SHOULD BE RELATIVELY LIGHT WITH
THE RIDGE AXIS JUST WWD OF THE CWA. GIVEN THE LIGHT WINDS AND H7
TEMPS AROUND 4 DEGREES OR SO...HAVE GONE ON THE LOW SIDE OF MOS FOR
TEMPS ON THE PLAINS...WITH HIGHS EXPECTED TO BE IN THE UPPER 60S TO
AROUND 70 DEGREES.
FRIDAY...FIRE WX ISSUES ARISE AS THE RIDGE SHIFTS TO THE EAST...AND
ZONAL FLOW STRENGTHENS ACROSS THE CONTDVD. SHOULD SEE MARGINALLY
CRITICAL FIRE WX CONDITIONS DEVELOP ACROSS THE PLAINS AS RH DROPS TO
BELOW 15 PERCENT AND W WINDS BECOME RATHER GUSTY BY AFTERNOON.
FOR THE WEEKEND...A WEAK SHORTWAVE TROUGH WILL MOVE THROUGH THE NRN
ROCKIES...AND WILL LIKELY SPARK SCT-NMRS SHOWERS ACROSS THE MTS
ESPECIALLY SAT AFTERNOON-EVE. MAIN CHANCES FOR PRECIP WILL BE N OF
HIGHWAY 50 BOTH DAYS. TEMPS SHOULD REMAIN QUITE PLEASANT...IN THE MID
60S ACROSS THE PLAINS AND 50S FOR THE MTS AND HIGH VALLEYS.
MAIN FOCUS IN THE EXTENDED CONTINUES TO BE THE LARGE SPRING STORM
SYSTEM THAT IS EXPECTED TO AFFECT OUR AREA BY LATE IN THE WEEKEND
THROUGH THE FIRST HALF OF NEXT WEEK. ENSEMBLE MEANS CONTINUE TO SHOW
A DEEP TROUGH MOVING THROUGH THE SRN ROCKIES FROM MON THROUGH
WEDNESDAY. OP RUNS OF THE GFS AND ECMWF ALSO CONTINUE TO SHOW A DEEP
TROUGH MOVING THROUGH THE SOUTHERN ROCKIES DURING THIS TIME FRAME.
HOWEVER...SIGNIFICANT DIFFERENCES REMAIN IN THE EVOLUTION OF THE
TROUGH PER THE GFS AND EC. THE 00Z EC IS MORE PROGRESSIVE...BUT
SPLITS THE TROUGH...WITH THE MAIN ENERGY ARRIVING SUNDAY NIGHT THRU
MONDAY...AND A SECONDARY LOW MOVING THROUGH NEXT WED. THE GFS BRINGS
THE LOW THROUGH IN ONE PIECE...BUT IS SLOWER AND TARGETS THE MON
NIGHT-TUESDAY TIME FRAME FOR THE HIGHEST POPS. BOTH MODELS PROG
SIGNIFICANT QPF FOR SE CO...BETWEEN 1-2 INCHES OF LIQUID FOR THE
SUN-WED TIME PERIOD. BOTH MODELS ALSO TARGET THE SERN MTS FOR THE
HIGHEST PRECIP POTENTIAL. WHILE SNOW LEVELS LOOK TO REMAIN FAIRLY
HIGH FOR THE BULK OF THIS EVENT...THE SE MTS ABOVE 7000 FEET WOULD
PICK UP SIGNIFICANT SNOWFALL IN EITHER SCENARIO. THE ECMWF BRINGS IN
UNUSUALLY COLD AIR BEHIND THE TROUGH BY WED...WITH H7 TEMPS
BOTTOMING OUT NEAR MINUS 16 DEGREES. IF THIS OCCURS...THE HIGH TEMPS
FOR NEXT WED MAY NEED TO BE SUBSTANTIALLY REDUCED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1121 AM MDT WED APR 3 2013
KCOS AND KPUB...EXPECT THE LOW CIGS TO CLEAR WITHIN THE NEXT HOUR
OR SO. SAT PIX IMGY CONTINUES TO SHOW LOW CLOUDS DISSIPATING FROM
NW/SE WITH TIME.
WINDS AT KCOS THIS AFTERNOON MAY BE QUITE VARIABLE. HI RES
SIMULATIONS SHOW A BOUNDARY EXTENDING E-W ACROSS W EL PASO COUNTY.
WINDS N OF THE BOUNDARY ARE NORTHERLY AND SOUTH OF THE BOUNDARY
THEY ARE SOUTHERLY. THIS BOUNDARY IS FCST TO WOBBLE DURING THE
AFTERNOON AND THIS COULD CAUSE WINDS TO VARY SUBSTANTIALLY OVER
THE KCOS TAF SITE. OVERALL...THE MODELS SHOW THE BOUNDARY STAYING
N OF KCOS PROPER...AND FOR THIS REASON I PUT IN A PREDOMINANT
SOUTHERLY WIND FOR KCOS THIS AFTERNOON.
IN ADDITION...I CANNOT RULE OUT SOME LOCAL GROUND FOG LATER
TONIGHT AT ALL 3 TAF SITES...BUT PROBABILITY IS TOO LOW FOR ME TO
MENTION IT EXPLICITLY IN THE TAF.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...PETERSEN
SHORT TERM...PETERSEN
LONG TERM...ROSE
AVIATION...HODANISH
AREA FORECAST DISCUSSION
NWS PUEBLO CO
700 AM MDT WED APR 3 2013
.UPDATE...
ISSUED AT 655 AM MDT WED APR 3 2013
UPDATED FORECAST TO REFLECT CURRENT CONDITIONS. REMOVED
DRIZZLE/FOG FROM SOUTHERN I-25 CORRIDOR AS VISIBILITY HAS BEEN
IMPROVING MOST AREAS. STILL SOME DENSE FOG AND PATCHY FREEZING
DRIZZLE ACROSS EL PASO COUNTY THROUGH MID-MRNG AS WINDS HAVE YET
TO GO NORTHERLY. ALSO ADDED A COUPLE HOURS OF LIGHT SNOW TO SAN
LUIS VALLEY...WHERE ALAMOSA HAS BEEN REPORTING SNOW THE PAST HOUR.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM MDT WED APR 3 2013
UPPER LOW GRADUALLY SLIPPING EASTWARD ACROSS THE STATE EARLY THIS
MORNING...AND SHOULD MOVE INTO THE SOUTHERN PLAINS BY THIS
EVENING. STILL SOME RESIDUAL -SHRA/-SHSN/-FZDZ ACROSS THE AREA
THIS MORNING...THOUGH RADAR TRENDS SUGGEST GRADUALLY DECREASING
COVERAGE AND INTENSITY SINCE 09Z. WILL HOLD ON TO SOME LIGHT
PRECIP THROUGH THE MORNING MOST AREAS...GRADUALLY ENDING FROM NW
TO SE BY MIDDAY. MAY SEE A FEW SHOWERS REFIRE OVER THE MTS THIS
AFTERNOON AS LAPSE RATES REMAIN FAIRLY STEEP...THOUGH PRECIP WILL
BE VERY LIGHT. PERSISTENT -FZDZ AND FZFG OVER EL PASO COUNTY MAY
LINGER THROUGH LATE MORNING...AS LATEST HRRR KEEPS WEAK SOUTHEAST
WIND IN PLACE UNTIL 17Z. STILL THINK N-NW FLOW WILL DEVELOP THIS
AFTERNOON AND GRADUALLY REMOVE ANY REMNANTS OF CLOUDS/FOG...THOUGH
FAR SOUTHEAST PLAINS MAY HAVE TO WAIT UNTIL VERY LATE AFTERNOON TO
SEE ANY SUN. WILL CONTINUE WITH REASONABLY MILD MAX TEMPS MOST
LOCATIONS...THOUGH KEPT AREAS AROUND SPRINGFIELD COLDER THAN
GUIDANCE DUE TO LINGERING CLOUDS. OVERNIGHT...WILL END PRECIP
QUICKLY IN THE EVENING WITH LOSS OF HEATING...LEADING TO A MOSTLY
CLEAR AND SEASONABLY COOL NIGHT MOST AREAS UNDER WEAK NORTHWEST
FLOW.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 352 AM MDT WED APR 3 2013
...SIGNIFICANT STORM POSSIBLE EARLY NEXT WEEK...
LATTER HALF OF THIS WEEK LOOKS QUITE PLEASANT AS A TRANSITORY RIDGE
CROSSES OUR AREA. THURSDAY MAY BE THE NICEST DAY...WITH DRY AND CLEAR
CONDITIONS EXPECTED AREA-WIDE. WINDS SHOULD BE RELATIVELY LIGHT WITH
THE RIDGE AXIS JUST WWD OF THE CWA. GIVEN THE LIGHT WINDS AND H7
TEMPS AROUND 4 DEGREES OR SO...HAVE GONE ON THE LOW SIDE OF MOS FOR
TEMPS ON THE PLAINS...WITH HIGHS EXPECTED TO BE IN THE UPPER 60S TO
AROUND 70 DEGREES.
FRIDAY...FIRE WX ISSUES ARISE AS THE RIDGE SHIFTS TO THE EAST...AND
ZONAL FLOW STRENGTHENS ACROSS THE CONTDVD. SHOULD SEE MARGINALLY
CRITICAL FIRE WX CONDITIONS DEVELOP ACROSS THE PLAINS AS RH DROPS TO
BELOW 15 PERCENT AND W WINDS BECOME RATHER GUSTY BY AFTERNOON.
FOR THE WEEKEND...A WEAK SHORTWAVE TROUGH WILL MOVE THROUGH THE NRN
ROCKIES...AND WILL LIKELY SPARK SCT-NMRS SHOWERS ACROSS THE MTS
ESPECIALLY SAT AFTERNOON-EVE. MAIN CHANCES FOR PRECIP WILL BE N OF
HIGHWAY 50 BOTH DAYS. TEMPS SHOULD REMAIN QUITE PLEASANT...IN THE MID
60S ACROSS THE PLAINS AND 50S FOR THE MTS AND HIGH VALLEYS.
MAIN FOCUS IN THE EXTENDED CONTINUES TO BE THE LARGE SPRING STORM
SYSTEM THAT IS EXPECTED TO AFFECT OUR AREA BY LATE IN THE WEEKEND
THROUGH THE FIRST HALF OF NEXT WEEK. ENSEMBLE MEANS CONTINUE TO SHOW
A DEEP TROUGH MOVING THROUGH THE SRN ROCKIES FROM MON THROUGH
WEDNESDAY. OP RUNS OF THE GFS AND ECMWF ALSO CONTINUE TO SHOW A DEEP
TROUGH MOVING THROUGH THE SOUTHERN ROCKIES DURING THIS TIME FRAME.
HOWEVER...SIGNIFICANT DIFFERENCES REMAIN IN THE EVOLUTION OF THE
TROUGH PER THE GFS AND EC. THE 00Z EC IS MORE PROGRESSIVE...BUT
SPLITS THE TROUGH...WITH THE MAIN ENERGY ARRIVING SUNDAY NIGHT THRU
MONDAY...AND A SECONDARY LOW MOVING THROUGH NEXT WED. THE GFS BRINGS
THE LOW THROUGH IN ONE PIECE...BUT IS SLOWER AND TARGETS THE MON
NIGHT-TUESDAY TIME FRAME FOR THE HIGHEST POPS. BOTH MODELS PROG
SIGNIFICANT QPF FOR SE CO...BETWEEN 1-2 INCHES OF LIQUID FOR THE
SUN-WED TIME PERIOD. BOTH MODELS ALSO TARGET THE SERN MTS FOR THE
HIGHEST PRECIP POTENTIAL. WHILE SNOW LEVELS LOOK TO REMAIN FAIRLY
HIGH FOR THE BULK OF THIS EVENT...THE SE MTS ABOVE 7000 FEET WOULD
PICK UP SIGNIFICANT SNOWFALL IN EITHER SCENARIO. THE ECMWF BRINGS IN
UNUSUALLY COLD AIR BEHIND THE TROUGH BY WED...WITH H7 TEMPS
BOTTOMING OUT NEAR MINUS 16 DEGREES. IF THIS OCCURS...THE HIGH TEMPS
FOR NEXT WED MAY NEED TO BE SUBSTANTIALLY REDUCED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 352 AM MDT WED APR 3 2013
AT KCOS...PERSISTENT SE SURFACE WIND HAS PRODUCED DENSE FZFG AND
FZDZ EARLY THIS MORNING...AND EXPECT LIFR CONDITIONS TO PERSIST
UNTIL 14Z...THEN IFR FROM 14-17Z AS FOG/CIGS BEGIN TO LIFT. PRECIP
AMOUNTS AND ANY ICING THIS MORNING SHOULD BE MINIMAL. WILL SEE VFR
CONDITIONS RETURN 17Z-18Z AS LIGHT NORTH WIND DEVELOP...THEN VFR
CONDITIONS FOR THE REMAINDER OF TODAY AND TONIGHT WITH LIGHT
WINDS. MAY SEE A -SHRA OVER THE MOUNTAINS WEST OF THE AIRPORT
AFTER 18Z...THOUGH CHANCE OF ANY SHOWERS AT THE TERMINAL LOOKS TOO
LOW TO MENTION IN THE TAF.
AT KPUB...E-SE WIND WILL KEEP IFR STRATUS IN PLACE UNTIL
14-15Z...THEN GRADUAL CLEARING BY 17Z AS WINDS BECOME LIGHT N.
EXPECT VFR CONDITIONS FROM 17Z ONWARD THROUGH THE AFTERNOON AND
OVERNIGHT WITH LIGHT WINDS.
AT KALS...SOME PATCHY MVFR STRATUS EARLY THIS MORNING WILL
DISSIPATE BY 14Z...THEN VFR CONDITIONS FOR THE REMAINDER OF TODAY
AND TONIGHT WITH LIGHT WINDS. MAY SEE A -SHRA OVER THE MOUNTAINS
SURROUNDING THE AREA AFTER 18Z...THOUGH IT APPEARS DOUBTFUL ANY
WILL MOVE TOWARD THE TERMINAL.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...PETERSEN
SHORT TERM...PETERSEN
LONG TERM...ROSE
AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS PUEBLO CO
428 AM MDT WED APR 3 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM MDT WED APR 3 2013
UPPER LOW GRADUALLY SLIPPING EASTWARD ACROSS THE STATE EARLY THIS
MORNING...AND SHOULD MOVE INTO THE SOUTHERN PLAINS BY THIS
EVENING. STILL SOME RESIDUAL -SHRA/-SHSN/-FZDZ ACROSS THE AREA
THIS MORNING...THOUGH RADAR TRENDS SUGGEST GRADUALLY DECREASING
COVERAGE AND INTENSITY SINCE 09Z. WILL HOLD ON TO SOME LIGHT
PRECIP THROUGH THE MORNING MOST AREAS...GRADUALLY ENDING FROM NW
TO SE BY MIDDAY. MAY SEE A FEW SHOWERS REFIRE OVER THE MTS THIS
AFTERNOON AS LAPSE RATES REMAIN FAIRLY STEEP...THOUGH PRECIP WILL
BE VERY LIGHT. PERSISTENT -FZDZ AND FZFG OVER EL PASO COUNTY MAY
LINGER THROUGH LATE MORNING...AS LATEST HRRR KEEPS WEAK SOUTHEAST
WIND IN PLACE UNTIL 17Z. STILL THINK N-NW FLOW WILL DEVELOP THIS
AFTERNOON AND GRADUALLY REMOVE ANY REMNANTS OF CLOUDS/FOG...THOUGH
FAR SOUTHEAST PLAINS MAY HAVE TO WAIT UNTIL VERY LATE AFTERNOON TO
SEE ANY SUN. WILL CONTINUE WITH REASONABLY MILD MAX TEMPS MOST
LOCATIONS...THOUGH KEPT AREAS AROUND SPRINGFIELD COLDER THAN
GUIDANCE DUE TO LINGERING CLOUDS. OVERNIGHT...WILL END PRECIP
QUICKLY IN THE EVENING WITH LOSS OF HEATING...LEADING TO A MOSTLY
CLEAR AND SEASONABLY COOL NIGHT MOST AREAS UNDER WEAK NORTHWEST
FLOW.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 352 AM MDT WED APR 3 2013
...SIGNIFICANT STORM POSSIBLE EARLY NEXT WEEK...
LATTER HALF OF THIS WEEK LOOKS QUITE PLEASANT AS A TRANSITORY RIDGE
CROSSES OUR AREA. THURSDAY MAY BE THE NICEST DAY...WITH DRY AND CLEAR
CONDITIONS EXPECTED AREA-WIDE. WINDS SHOULD BE RELATIVELY LIGHT WITH
THE RIDGE AXIS JUST WWD OF THE CWA. GIVEN THE LIGHT WINDS AND H7
TEMPS AROUND 4 DEGREES OR SO...HAVE GONE ON THE LOW SIDE OF MOS FOR
TEMPS ON THE PLAINS...WITH HIGHS EXPECTED TO BE IN THE UPPER 60S TO
AROUND 70 DEGREES.
FRIDAY...FIRE WX ISSUES ARISE AS THE RIDGE SHIFTS TO THE EAST...AND
ZONAL FLOW STRENGTHENS ACROSS THE CONTDVD. SHOULD SEE MARGINALLY
CRITICAL FIRE WX CONDITIONS DEVELOP ACROSS THE PLAINS AS RH DROPS TO
BELOW 15 PERCENT AND W WINDS BECOME RATHER GUSTY BY AFTERNOON.
FOR THE WEEKEND...A WEAK SHORTWAVE TROUGH WILL MOVE THROUGH THE NRN
ROCKIES...AND WILL LIKELY SPARK SCT-NMRS SHOWERS ACROSS THE MTS
ESPECIALLY SAT AFTERNOON-EVE. MAIN CHANCES FOR PRECIP WILL BE N OF
HIGHWAY 50 BOTH DAYS. TEMPS SHOULD REMAIN QUITE PLEASANT...IN THE MID
60S ACROSS THE PLAINS AND 50S FOR THE MTS AND HIGH VALLEYS.
MAIN FOCUS IN THE EXTENDED CONTINUES TO BE THE LARGE SPRING STORM
SYSTEM THAT IS EXPECTED TO AFFECT OUR AREA BY LATE IN THE WEEKEND
THROUGH THE FIRST HALF OF NEXT WEEK. ENSEMBLE MEANS CONTINUE TO SHOW
A DEEP TROUGH MOVING THROUGH THE SRN ROCKIES FROM MON THROUGH
WEDNESDAY. OP RUNS OF THE GFS AND ECMWF ALSO CONTINUE TO SHOW A DEEP
TROUGH MOVING THROUGH THE SOUTHERN ROCKIES DURING THIS TIME FRAME.
HOWEVER...SIGNIFICANT DIFFERENCES REMAIN IN THE EVOLUTION OF THE
TROUGH PER THE GFS AND EC. THE 00Z EC IS MORE PROGRESSIVE...BUT
SPLITS THE TROUGH...WITH THE MAIN ENERGY ARRIVING SUNDAY NIGHT THRU
MONDAY...AND A SECONDARY LOW MOVING THROUGH NEXT WED. THE GFS BRINGS
THE LOW THROUGH IN ONE PIECE...BUT IS SLOWER AND TARGETS THE MON
NIGHT-TUESDAY TIME FRAME FOR THE HIGHEST POPS. BOTH MODELS PROG
SIGNIFICANT QPF FOR SE CO...BETWEEN 1-2 INCHES OF LIQUID FOR THE
SUN-WED TIME PERIOD. BOTH MODELS ALSO TARGET THE SERN MTS FOR THE
HIGHEST PRECIP POTENTIAL. WHILE SNOW LEVELS LOOK TO REMAIN FAIRLY
HIGH FOR THE BULK OF THIS EVENT...THE SE MTS ABOVE 7000 FEET WOULD
PICK UP SIGNIFICANT SNOWFALL IN EITHER SCENARIO. THE ECMWF BRINGS IN
UNUSUALLY COLD AIR BEHIND THE TROUGH BY WED...WITH H7 TEMPS
BOTTOMING OUT NEAR MINUS 16 DEGREES. IF THIS OCCURS...THE HIGH TEMPS
FOR NEXT WED MAY NEED TO BE SUBSTANTIALLY REDUCED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 352 AM MDT WED APR 3 2013
AT KCOS...PERSISTENT SE SURFACE WIND HAS PRODUCED DENSE FZFG AND
FZDZ EARLY THIS MORNING...AND EXPECT LIFR CONDITIONS TO PERSIST
UNTIL 14Z...THEN IFR FROM 14-17Z AS FOG/CIGS BEGIN TO LIFT. PRECIP
AMOUNTS AND ANY ICING THIS MORNING SHOULD BE MINIMAL. WILL SEE VFR
CONDITIONS RETURN 17Z-18Z AS LIGHT NORTH WIND DEVELOP...THEN VFR
CONDITIONS FOR THE REMAINDER OF TODAY AND TONIGHT WITH LIGHT
WINDS. MAY SEE A -SHRA OVER THE MOUNTAINS WEST OF THE AIRPORT
AFTER 18Z...THOUGH CHANCE OF ANY SHOWERS AT THE TERMINAL LOOKS TOO
LOW TO MENTION IN THE TAF.
AT KPUB...E-SE WIND WILL KEEP IFR STRATUS IN PLACE UNTIL
14-15Z...THEN GRADUAL CLEARING BY 17Z AS WINDS BECOME LIGHT N.
EXPECT VFR CONDITIONS FROM 17Z ONWARD THROUGH THE AFTERNOON AND
OVERNIGHT WITH LIGHT WINDS.
AT KALS...SOME PATCHY MVFR STRATUS EARLY THIS MORNING WILL
DISSIPATE BY 14Z...THEN VFR CONDITIONS FOR THE REMAINDER OF TODAY
AND TONIGHT WITH LIGHT WINDS. MAY SEE A -SHRA OVER THE MOUNTAINS
SURROUNDING THE AREA AFTER 18Z...THOUGH IT APPEARS DOUBTFUL ANY
WILL MOVE TOWARD THE TERMINAL.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...PETERSEN
LONG TERM...ROSE
AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS TOPEKA KS
633 PM CDT THU APR 4 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 306 PM CDT THU APR 4 2013
LIGHT SURFACE PRESSURE GRADIENT IS EVIDENT IN 20Z RAP ANALYSIS. THIS
LIGHT PRESSURE GRADIENT IS RESPONSIBLE FOR LIGHT WINDS WHICH ARE
EVIDENT IN SURFACE OBSERVATIONS ACROSS THE FORECAST AREA THIS
AFTERNOON. EXPECT THESE LIGHT WINDS TO EVENTUALLY SHIFT TO THE SOUTH
OVERNIGHT TONIGHT AS A SURFACE LOW COMES INTO FORMATION OVER THE
HIGH PLAINS. SOUTHERLY WINDS WILL INCREASE THROUGH THE DAY ON FRIDAY
TO AROUND 20 TO 25 MPH...WITH GUSTS TO AROUND 30 MPH. DEEP MIXING
WILL CAUSE ALLOW FOR LOW LEVEL WINDS AROUND 850 MB TO COME TO THE
SURFACE...WHICH MAY BRING WARMER/DRYER CONDITIONS AND STRONGER WIND
GUSTS. THIS WILL HAVE FIRE WEATHER IMPLICATIONS...WHICH ARE
DISCUSSED IN THE FIRE WEATHER DISCUSSION BELOW. AT THIS TIME EXPECT
VERY HIGH FIRE DANGER FOR MOST OF THE AREA THROUGH THE DAY ON
FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 306 PM CDT THU APR 4 2013
FRIDAY NIGHT THROUGH SUNDAY...FRIDAY NIGHT LEE SIDE LOW PRESSURE
DEEPENS OVER THE HIGH PLAINS INCREASING THE PRESSURE GRADIENT
ACROSS THE AREA. THEREFORE THE WINDS WILL CONTINUE TO BE GUSTY
THROUGH THE OVERNIGHT HOURS ESPECIALLY ACROSS EASTERN KANSAS. THIS
WILL KEEP LOW TEMPERATURES FRIDAY NIGHT IN THE LOW 50S. A
SOUTHWESTERLY LOW LEVEL JET INCREASES FRIDAY NIGHT BRINGING
LIMITED MOISTURE TO THE REGION. MEANWHILE A SHORTWAVE ADVANCES
EASTWARD INTO NEBRASKA AND EVENTUALLY IOWA ON SATURDAY. IT APPEARS
THAT THE STRONGER LIFT ASSOCIATED WITH THE WAVE WILL BE NORTH OF
THE AREA FRIDAY NIGHT AND SATURDAY MORNING. THERE IS SLIGHT CHANCE
OF SOME WEAK LIFT EXTENDING SOUTH INTO KANSAS SO COULD NOT RULE
OUT AN ISOLATED SHOWER FRIDAY NIGHT. A WEAK COLD FRONT ASSOCIATED
WITH THE WAVE WILL PUSH SOUTHWARD THROUGH THE AREA DURING THE DAY
ON SATURDAY SHIFTING THE WINDS TO THE NORTH. THE FRONT WILL
RETREAT BACK TO THE NORTH ON SUNDAY AND SETS UP SOMEWHERE IN
NORTHEAST KANSAS. A WEAK SHORTWAVE EMBEDDED IN THE ZONAL MID LEVEL
FLOW PROGRESSES EASTWARD ACROSS KANSAS DURING THE DAY PROVIDING
LAGER SCALE LIFT. SOUTHERLY LOW LEVEL FLOW WILL INCREASE THE
MOISTURE RETURN ACROSS THE AREA AS ML CAPE VALUES APPROACH 500
J/KG AIDING IN THUNDERSTORM DEVELOPMENT. MID LEVEL FLOW ALSO
INCREASES SUNDAY WITH 0-6 KM BULK SHEAR VALUES AROUND 40 KTS WHICH
SUPPORTS THE CHANCE OF STRONGER ORGANIZED THUNDERSTORMS SUNDAY
AFTERNOON AND OVERNIGHT.
EXTENDED FORECAST (SUN NIGHT-THURS)...AN ACTIVE PATTERN SETTING UP
THROUGH THIS PERIOD...AND SEVERE WEATHER APPEARS INCREASINGLY
LIKELY....HOWEVER TIMING AND PLACEMENT REMAINS SOMEWHAT
UNCERTAIN. SUNDAY NIGHT THE GFS AND A SOMEWHAT FASTER EC BRING A
SHORTWAVE OVER THE WARMFRONT PROGGED E/W OVER OUR AREA...WITH THE
EC HOLDING THE FRONT FARTHER SOUTH THAN THE GFS. ENOUGH CAPE AND
SHEAR PRESENT THAT SOME OF THE STORMS OVERNIGHT COULD BRING HAIL.
THE ENSUING WEATHER FOR MONDAY WILL BE DEPENDENT ON HOW FAR NORTH
THE WARMFRONT LIFTS DURING THE DAY. EC AND GFS BOTH BREAK OUT
CONVECTION NEAR THE BOUNDARY AND LESS SO IN THE WARM SECTOR MONDAY
EVENING THROUGH THE MORNING HOURS ON TUESDAY. SEVERE WEATHER
POTENTIAL CONTINUES TO INCREASE INTO TUESDAY AND TUESDAY
AFTERNOON AS WESTERN TROF APPROACHES...AND SHEAR AND INSTABILITY
ALSO INCREASE AND MOVE NORTH ACROSS THE CWA WITH THE WARM SECTOR.
DIFFERENCES INCREASE BEYOND TUESDAY AS GFS MOVES THE COLDFRONT
THROUGH QUICKLY WITH EC DROPPING A CLOSED UPPER LOW ACROSS EASTERN
KANSAS AND THE FRONT MOVING THROUGH WEDNESDAY EVENING. WHILE
WED/THURS WILL BRING A COOL END OF THE WEEK...MUCH UNCERTAINTY
WITH PRECIP AMOUNTS AND TYPES. 67
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 625 PM CDT THU APR 4 2013
EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD. SOUTHERLY WINDS
WILL INCREASE TOMORROW MORNING TO AROUND 15 TO 25 MPH WITH GUSTS
UP TO 30 MPH DECREASING AROUND SUNSET TOMORROW EVENING.
SANDERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...LEIGHTON
LONG TERM...67
AVIATION...SANDERS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
959 PM EDT THU APR 04 2013
.Forecast Update...
Issued at 958 PM EDT Thu Apr 4 2013
Confidence in fog tonight across southern Kentucky continues to
increase. Clouds have continued their slow southeastward
progression this evening, a trend which should continue through the
overnight hours. Webcams across southern Kentucky are already
showing some light fog developing, despite the lower clouds in
place. As these clouds clear tonight, think fog will really become
more widespread and thicken overnight into the morning hours on
Friday (almost all hi-res guidance supports this thinking). Have
updated the grids to include areas of fog, and have also updated the
HWO to highlight the potential of dense fog.
There remain some questions on the northern extent of the fog
potential, as some hi-res guidance develops it as far north as
Louisville. However, the last several runs of the RAP and HRRR have
initialized dewpoints across central KY about 5 degrees too high,
thus think that their depiction of the fog potential is too far
north. Will keep fog wording only where measurable precipitation
fell today, which are the areas southeast of a line from Butler to
Madison county.
&&
.Short Term (Tonight - Friday night)...
Issued at 230 PM EDT Thu Apr 4 2013
The previously advertised upper-level trough currently making its
way across the southern U.S. will have exited the Ohio Valley by
tomorrow, transitioning into a zonal flow pattern by the end of this
forecast period. Lower in the atmosphere, ridging will take back
over as surface high pressure moseys across the Great Lakes and into
New England by early Saturday.
Radar has been showing widespread reflectivity across the southern
half of the commonwealth and into Tennessee. However, much of the
returns haven`t been reaching the ground as rain along the northern
extent of this virga shield. The lower atmosphere has been
attempting to moisten up along and south of the Bluegrass Pkwy as a
tight dewpoint gradient makes its way north. While mid-level dry air
remains fixed in place across the northern portions of the forecast
area, there is still a chance for sprinkles to potentially fall
south of the Ohio River this evening through early tonight. It won`t
take long for the aforementioned ridging to set back up over the
region so lingering precip and much of the cloud deck is expected to
be shunted off toward the east by daybreak Friday. Dewpoint
depressions are expected to be minimal at this point and with the
winds calming overnight, there is a possibility of fog to develop in
prone locations, especially in those locations that received
measurable rain today. By the time Friday afternoon rolls around,
expect a pleasant spring day to be underway as only fair weather
cumulus clouds appear to be the only thing dotting the skies under
light northwest winds.
As those clouds exit the area tonight, expect low temperatures to
drop back off into the mid to upper 30s. For tomorrow afternoon,
highs are anticipated to be closer to normal, reaching the low to
mid 60s. Overnight lows Friday should be slightly warmer than
tonight`s with many locations staying above the 40 degree mark, with
the exception primarily being in the Bluegrass region where lows
will be in the upper 30s.
.Long Term (Saturday - Thursday)...
Issued at 238 PM EDT Thu Apr 4 2013
Strengthening mid-level westerly flow will push the polar jet to the
north, allowing low-level southwesterly flow to bring warm and moist
air northeast into the Ohio Valley. Temperatures over the Ohio
Valley will warm substantially this weekend, with mild temperatures
continuing through at least Wednesday of next week. A
quasi-stationary surface boundary will set up across the Ohio
Valley, with several episodes of convection likely from Sunday
afternoon through Thursday, particularly for locations along and
north of the Ohio River.
Low pressure will move across Wisconsin Saturday afternoon, with a
trailing cold front pushing across Missouri. Southwest winds will
increase across the Ohio Valley as a tightening pressure gradient
develops by Saturday afternoon. Temperatures will also be on the
increase under partly cloudy skies, with upper 60s to lower 70s
expected across the forecast area. As the surface low tracks
northeast into the Upper Great Lakes region, the cold front will
stall across southern Illinois and central Indiana during the day
Sunday, as this boundary parallels flow aloft. It appears the
stalled front will stay just north of the forecast area so that
Kentucky and southern Indiana stay within southwesterly flow. As
moisture pools along this boundary, increased cloudiness and a
chance of showers and thunderstorms will be possible by Sunday
afternoon. Given the position of the boundary, it appears locations
along and north of the Ohio River stand the best chance of rain
Sunday.
Another area of low pressure is forecast to move over Illinois and
push into the Great Lakes Monday and Monday night. This system
should act to push the stalled boundary northward as a warm front
during the day Monday, before a trailing cold front slides south and
stalls across basically the same location (southern IL and central
IN) Monday night into Tuesday. Active weather will follow the
northward lifting boundary Monday and return with the approach of
the stalling cold front Monday night into Tuesday. Once again, our
northern forecast area will stand the best chance of showers and
thunderstorms. High temperatures in the upper 60s and lower 70s
appear on tap again Monday, with temperatures several degrees warmer
possible Tuesday.
The boundary that slides into central Indiana early Tuesday will
lift north through the day and overnight as yet another system
pushes through southern Illinois and central Indiana Tuesday night
and Wednesday. This system will slide a trailing frontal boundary
southward as well and this time it looks like it will get into our
forecast area Wednesday. Just how far south it travels remains a big
question. So, once again, showers and storms will be likely near the
northward lifting boundary Tuesday, and then slide back into at
least our northern CWA for Wednesday with the trailing front. A
deepening trough across the Plains Wednesday will slowly move east
through Thursday. This will send what appears to be our last low
pressure system through the Ohio Valley Thursday, with the upper
trough clearing the remaining precip out of the area Thursday night
into Friday. Temperatures will remain warm Wednesday and Thursday,
with upper 60s to lower 70s for highs.
&&
.Aviation (00Z TAF Issuance)...
Issued at 718 PM EDT Thu Apr 4 2013
Clouds associated with a shortwave trough moving across the
southern United States continue to affect the Ohio Valley this
evening. Dry air has kept any and all precipitation confined to
southern KY around KBWG, and expect this to continue for the next
couple of hours. Tonight, the system will push east and allow skies
to clear from west to east across all terminals.
The clearing skies may allow some fog to form at KBWG, where
sufficient ground moisture due to the rainfall and light winds will
reside. Will drop visibilities into IFR overnight. This may need
to be refined depending on the exact time skies clear out, but there
is certainly enough potential in IFR visibilities (perhaps even
LIFR) to warrant mention with this package. KLEX and KSDF have
remained well within the dry air today, so fog potential at these
sites look low at this time.
Otherwise, any fog near KBWG will quickly mix out on Friday, leaving
only a few cu and northerly winds at 5-10 knots.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........KD
Short Term.......lg
Long Term........MJP
Aviation.........KD
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
743 PM EDT THU APR 4 2013
.SYNOPSIS...
LOW PRESSURE LIFTS NORTHEAST FROM THE GULF COAST THROUGH TONIGHT.
THIS AREA OF LOW PRESSURE TRACKS ALONG THE SOUTHEAST COAST
OVERNIGHT BEFORE SLIDING OFF THE MID ATLANTIC COAST FRIDAY. HIGH
PRESSURE BUILDS OVER THE REGION SATURDAY AND SHIFTS OFFSHORE
SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
UPDATED GRIDS/ZFP PER RAPIDLY CHANGING CNDTNS ACROSS THE FA ATTM.
NMRS RPTS OF SLEET MIXING IN WITH THE RAIN AT THE ONSET AS FAR
EAST AS VA BCH...SO ADDED IP TO THE GRIDS NEXT FEW HRS. ALSO...DUE
TO THE LARGE TMP/DP TMPS GAP...SFC TMPS QUICKLY FALLING INTO THE
U30S-L40S WHERE PCPN CONTS TO SATURATE THE LYR. THUS...MADE CHANGES
TO TMP GRIDS. CHALLENGING TMP FCST NEXT 6-12 HRS AS READINGS XPCTD
TO LEVEL OFF AT SOME POINT ONCE THE RAIN SATURATES COLUMN THEN STDY
OR SLOWLY RISE AFTR MIDNIGHT IN ADVANCE OF SFC LOW. TMPS MAY EVEN
RISE INTO THE 50S ACROSS NRN OB/VA BCH AREAS LATE TONITE B4 FALLING
BACK INTO THE 40S ONCE THE LOW MOVES NE.
PVS DSCN:
LATEST UPPER AIR ANALYSIS SHOWS A NORTHERN STREAM TROUGH TREKKING
ACROSS ONTARIO THIS AFTN, AS A SOUTHERN STREAM TROUGH IS NOW
ORIENTED OVER TEXARKANA/SOUTHERN MS VLY. AT THE SURFACE, WEAKENING
~1028MB SFC HIGH PRESSURE NOW ORIENTED JUST OFFSHORE, SETTING UP A
HYBRID COLD AIR DAMMING WEDGE STRUCTURE OVER THE REGION. TO THE
SOUTHWEST, A 1012MB LOW PRESSURE CENTER WAS CENTERED OVER THE FL
PANHANDLE...WITH INVERTED COASTAL TROUGH ANALYZED OFFSHORE OF THE
GA/SC COAST.
LOW PRESSURE OVER THE SOUTHEAST WILL LIFT NORTHEAST AS MS VLY
TROUGH WOBBLES EAST SOUTHEAST THROUGH THE EVENING. HAVE SEEN A
HANDFUL OF SLEET REPORTS JUST TO OUR SOUTH/SOUTHWEST THANKS TO
EVAPORATIONAL COOLING IN ANTECEDENT MODIFIED CP AIRMASS.
ISENTROPIC UPGLIDE (290-300K SURFACES) RAMP UP QUICKLY LATE THIS
AFTERNOON AND THIS EVENING AS SSW MID-LEVEL FLOW INCREASES ACROSS
THE SOUTHEAST AND LOWER MID- ATLANTIC. THIS WILL SLOWLY SPREAD RAIN
NORTH-NORTHEAST OVER THE AREA TONIGHT. RUC SOUNDINGS DO ARGUE FOR
A BRIEF PERIOD OF SLEET ACROSS THE PIEDMONT, SOUTH CENTRAL VA/INTR
NE NC, QUICKLY BECOMING ALL RAIN AS WAA CONTINUES AND LLVLS BECOME
SATURATED. CONSIDERING ROAD TEMPS WELL ABOVE FREEZING, THIS SHOULD
BE A MINIMAL IMPACT, BUT NONETHELESS WORTH MENTIONING IN THE GOING
FORECAST.
THE MID-LEVEL TROUGH TRACKS OVER THE DEEP SOUTH TONIGHT...WITH
THE SURFACE LOW PRESSURE TRACKING NE OFF THE COAST ALONG THE
COASTAL BOUNDARY...WITH SOME ADDITIONAL NUDGING FROM THE NORTHERN
STREAM TROUGH. RATHER VIGOROUS VERTICAL ASCENT IS PROGGED TO MOVE
NE ACROSS THE LOCAL AREA BETWEEN 00-09Z...WHICH SHOULD BRING A
PERIOD OF MODERATE COLD RAIN TO MUCH OF THE AREA...CENTERED/HEAVIEST
FROM S-CENTRAL VA TO THE EASTERN SHORE. BRIEF WINDOW OF MAINLY
ELEVATED INSTABILITY ARRIVES AFTER MIDNIGHT. TOTAL TOTALS IN THE
LOW 50S, WITH ENOUGH VERTICAL ASCENT TO OVERCOME NEUTRAL LI
VALUES WOULD ARGUE FOR PERHAPS A RUMBLE OF THUNDER OR TWO ACROSS
THE FAR SOUTHEAST, SO HV ADDED A SLIGHT RISK FOR THUNDER AFTER
MIDNIGHT OVER FAR SE VA/NE NC. RAINFALL RATES SHOULD TAPER OFF
QUICKLY AS THE PRIMARY FORCING MOVES OFF THE COAST TOWARDS DAWN
FRIDAY MORNING. HOWEVER...LINGERING LOW-LEVEL MOISTURE SHOULD
ALLOW FOR STRATUS AND AREAS OF LIGHT RAIN/DRIZZLE. QPF AMOUNTS
RANGE FROM 0.5IN FAR NW...TO 1.25 ACROSS S-CENTRAL VA TO THE
COASTAL ZONES. LOWS SHOULD RANGE FROM THE M/U 30S NW...TO THE MID
40S SE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
LOW STRATUS AND AREAS OF LIGHT RA/DZ WILL LINGER FRIDAY MORNING,
BEFORE GRADUALLY CLEARING FROM NW TO SE AS WINDS BACK TO THE N-NW.
RAIN CHANCES ALSO DROP OFF QUICKLY AFTER 15Z AS MODEL CROSS
SECTIONS SHOW MID-LEVELS DRYING OUT QUICKLY. HIGHS SHOULD RANGE
FROM THE MID-UPPER 50S ALONG THE IMMEDIATE COAST...TO THE LOW 60S
INLAND.
HIGH PRESSURE BUILDS OVER THE AREA LATE FRIDAY NIGHT THROUGH
SATURDAY MORNING, BEFORE SLIDING OFFSHORE LATER SATURDAY.
QUASI-ZONAL/FLAT FLOW ALOFT ALLOWS DRIER AIR TO FILTER IN FROM THE
WEST FRIDAY AND SATURDAY. THUS, APART FROM SOME DIURNALLY DRIVEN
CUMULUS SATURDAY MORNING/AFTN, COURTESY OF ONSHORE (E-SE) LOW LEVEL
FLOW, EXPECT A MAINLY CLEAR SKY DURING THIS PERIOD. BY SUNDAY, FLOW
ALOFT OVER THE EASTERN THIRD OF THE COUNTRY BECOMES S-SW, AS UPPER
TROUGH COMES ASHORE THE PACIFIC COAST. THIS SHOULD EVENTUALLY LEAD
TO A WARM-UP BY LATE IN THE WEEKEND. CLEAR SKY/DRY AIRMASS SHOULD
BRING CHILLY EARLY MORNING SATURDAY AND SUNDAY MORNINGS. LOWS FROM
THE MID 30S N/NW TO LOW 40S SE COAST SAT MORNING...U30S TO MID 40S
SUNDAY MORNING. FORECAST HIGHS SAT RANGE FROM THE UPPER 40S/LOW
50S ALONG THE IMMEDIATE ATLANTIC COAST OF THE EASTERN SHORE TO
LOW 60S FROM THE I-95 CORRIDOR WEST. HIGHS WARM WELL INTO THE 60S
ON SUNDAY, WITH LOW 70S LIKELY WEST OF THE CHES BAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
12Z GFS/ECMWF IN GENERAL AGREEMENT SUN NGT INTO TUE MORNG...THEN
ARE QUITE DIFFERENT FOR TUE THRU THU. GFS MAINTAINS A WARMER
SCENARIO THRU THE PERIOD...KEEPING A FRNTL BOUNDARY N OF THE CWA
WITH AN UA RDG BLDNG OVR THE MID ATLC REGION TUE THRU WED...THEN
IT SLIDES OUT TO SEA WED NGT AND THU. WHILE...THE ECMWF KEEPS THE
FRNTL BOUNDARY NW OR N OF THE CWA SUN NGT INTO TUE MORNG...THEN
DROPS THE FRNT DOWN ACRS THE AREA TUE AFTN INTO WED...THEN
LINGERING THE FRNT NEAR THE VA/NC BORDER THRU THU. AT THIS TIME
GOING WITH THE WARMER GFS MODEL THRU THE PERIOD...WITH JUST A SLGT
OR SML CHC FOR SHOWERS POSSIBLE WED THRU THU. MAX TEMPS WILL RANGE
FM THE MID 60S TO MID 70S MON...AND IN THE UPR 60S TO UPR 70S TUE
THRU THU. MIN TEMPS WILL BE IN THE MID 40S TO LWR 50S MON
MORNG...AND MAINLY IN THE LWR TO MID 50S TUE...WED...AND THU
MORNGS.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
PRECIPITATION IS OVER SPREADING THE AREA NOW. WITH VERY DRY
CONDITIONS IN THE LOW LEVELS CIGS AND VSBY ARE STARTING IN THE VFR
RANGE WHEN PRECIPITATION ARRIVES. CAN SEE LOWER CIGS TO THE SOUTH
AND WITH TIME THIS AIR MASS WILL ARRIVE. TIMING ON THE SREF LOOKS
TO BRING IFR IN FROM THE SOUTH STARTING BETWEEN 03Z TO 06Z AND
THEN OVER SPREADING THE ENTIRE AREA SHORTLY AFTER 06Z. LOOKING AT
RAP BUFKIT SOUNDINGS GOES ALONG WITH THIS TIMING. SO USED THIS IN
THE TAFS WITH ORF AND ECG GOING FIRST AND THEN WORKING NORTH WITH
SBY GOING BY 07Z. COULD SEE SOME SLEET IN SBY OR RIC EARLY IN THE
PRECIP BUT WILL BECOME JUST RAIN QUICKLY. TIMING OF IMPROVING
CONDITIONS ON FRI HAS EVERYONE BACK TO AT LEAST MVFR CIGS DURING
THE MORNING AND BECOMING VFR BY AFTERNOON WITH CLOUDS SLOWLY
CLEARING. IFR CONDITIONS HANG ON LONGEST INTO THE MORNING IN THE
EAST WITH RIC GOING FIRST. STILL SOME UNCERTAINTY ON TIMING OF HOW
FAST CONDITIONS IMPROVE BUT ALL MODELS AGREE WITH AT LEAST MVFR
CONDITIONS BY MID TO LATE MORNING AT ALL TAF SITES. HI PRES BLDS
IN LATE FRI INTO THE WEEKEND LEADING TO VFR CONDITIONS.
&&
.MARINE...
AS LOW PRESSURE CONTINUES TO DEVELOP OFF NC COAST CAN SEE WINDS
ALREADY INCREASING. CURRENT PRESSURE FALLS SUPPORT THE LOW
DEEPENING QUICKLY WITH INCREASING WINDS NOTED ALREADY UP TO
ALBEMARLE SOUND. HAVE MOVED THE TIMING OF THE SMALL CRAFT ADVISORY
EARLIER AND EXTENDED IT INTO THE MOUTH OF THE JAMES RIVER AS WELL.
AS LOW INTENSIFIES TONIGHT COULD SEE SOME WIND GUSTS OVER THE
OCEAN NEAR GALES FOR A SHORT TIME. THE LOW WILL MOVE TO THE
NORTHEAST AWAY FROM THE AREA ON FRIDAY AS HI PRES STARTS TO BLD
IN FM THE NW. THE HI WILL MOVE RIGHT OVR THE REGION SAT MORNG.
THIS WILL RESULT IN STRONG N WNDS FM FRI MORNG INTO SAT
MORNG...WITH SCA`S FOR ALL WTRS EXCEPT THE RIVERS. HI PRES WILL
THEN SLIDE OFF THE CST FOR SUN THRU AT LEAST MON.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EDT FRIDAY FOR ANZ630>634.
SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 7 PM EDT
FRIDAY FOR ANZ638.
SMALL CRAFT ADVISORY UNTIL NOON EDT SATURDAY FOR ANZ654-656-
658.
SMALL CRAFT ADVISORY FROM 2 AM FRIDAY TO NOON EDT SATURDAY FOR
ANZ650-652.
&&
$$
SYNOPSIS...MAM
NEAR TERM...MPR/MAM
SHORT TERM...MAM
LONG TERM...TMG
AVIATION...MAS/JAB
MARINE...TMG
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1116 PM EDT THU APR 4 2013
.SYNOPSIS...
ISSUED AT 344 PM EDT THU APR 4 2013
A COLD FRONT IS MOVING THROUGH NORTHERN MICHIGAN...BRINGING A
PERIOD OF LIGHT RAIN AND SNOW FOR THIS AFTERNOON AND TONIGHT.
SETTLED WEATHER WILL RETURN FOR A SHORT TIME ON FRIDAY...BEFORE
ANOTHER STORM SYSTEM MOVES INTO NORTHERN MICHIGAN...BRINGING RAIN
AND SNOW MIXED FOR SATURDAY INTO SUNDAY.
&&
.UPDATE...
ISSUED AT 1115 PM EDT THU APR 4 2013
ALL SYNOPTICALLY DRIVEN SNOW HAS EXITED OUT OF OUR CWA LATE THIS
EVENING ALONG THE DEPARTING COLD FRONT. RESIDUAL SCT/BKN LOW
CLOUDS BEHIND THE FRONT ARE SHOWING SIGNS OF BECOMING LAKE
ENHANCED PER LATEST 11U-3.9U SATELLITE LOOP. LAST FEW FRAMES FROM
KMQT 88D SHOWS THE BEGINNINGS OF SOME VERY LIGHT LAKE EFFECT
FLURRIES/SNOW SHOWERS THANKS TO CAA AND N/NW FLOW OFF OF LAKE
SUPERIOR. AIRMASS FILTERING IN BEHIND THE COLD FRONT IS QUITE
DRY...BUT WITH 850 MB TEMPS DROPPING INTO THE MID TEENS...EXPECT
AT LEAST SOME N/NW FLOW LAKE FLURRIES/LIGHT SNOW SHOWERS WILL
DEVELOP OVERNIGHT. LOW CLOUDS WILL DIMINISH OVERNIGHT AWAY FROM ANY
LAKE INFLUENCES AS DRIER SYNOPTIC AIR ADVECTS INTO THE REGION.
ALSO EXPECT AREAS OF FOG THAT DEVELOP ACROSS PORTIONS OF NRN LWR
MICHIGAN WILL EVENTUALLY DISSIPATE LATE TONIGHT/EARLY FRIDAY
THANKS TO THAT DRIER AIR. UPSTREAM DWPTS IN THE 20S CERTAINLY
SUPPORTS OVERNIGHT LOWS IN THE 20S.
UPDATE ISSUED AT 700 PM EDT THU APR 4 2013
LINE OF RAIN/SNOW SHOWERS ACCELERATED SE EARLY THIS EVENING IN
RESPONSE TO A 125 KT 300 MB JET MAX DIGGING INTO THE WRN GREAT
LAKES REGION. HAVE MADE SEVERAL MODIFICATIONS TO TIMING AS A
RESULT...AND ALL PRECIP ASSOCIATED WITH THE FRONT SHOULD CLEAR OUR
CWA WITHIN THE NEXT HOUR OR SO. SOME CLEARING WILL TAKE PLACE...
EXPECT FOR LOCATIONS DOWNSTREAM OF LAKES SUPERIOR AND MICHIGAN
UNDER THE DIRECTION OF N/NW FLOW. LAKE CLOUDS AND SOME
FLURRIES/LIGHT SNOW SHOWERS SHOULD DEVELOP WITHIN THESE AREAS AND
PERSIST THE REST OF THE NIGHT AND INTO FRIDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 344 PM EDT THU APR 4 2013
THE CURRENT RADAR SHOWS A NARROW BAND OF PCPN SLOWLY DROPPING SOUTH
ACROSS NORTHERN LOWER MICHIGAN. THIS NARROW AREA OF PRECIPITATION IS
THE RESULT OF A COLD FRONT SINKING SOUTH OVER THE REGION. VIS SAT
AND SFC OBS SHOW LIMITED MOISTURE EITHER SIDE OF THE BOUNDARY...WITH
MOSTLY SUNNY SKIES OVER MUCH OF CENTRAL AND SOUTHERN MICHIGAN. SUN
OVER THE SRN CWA FROM EARLIER TODAY...HAS ALLOWED AFTERNOON TEMPS IN
THESE AREAS TO WARM QUICKLY INTO THE MID AND UPPER 40S...WHILE
TEMPS REMAIN IN THE 30S OVER ERN UPPER NORTH OF THE BOUNDARY.
OVERALL THE MAIN FORECAST CONCERNS TONIGHT THROUGH FRIDAY WILL BE
TIMING AND TYPE OF PCPN TONIGHT WITH THE APPROACHING FRONT...ALONG
WITH ANY LAKE INDUCED SNOWS FRIDAY ON THE BACKSIDE OF THE COLD
FRONT.
THE STORM SYSTEM CURRENTLY MOVING ACRS ONTARIO WILL QUICKLY EXIT
INTO QUEBEC THIS EVENING. A COLD FRONT ASSOCIATED WITH THIS SYSTEM...
WILL CONT TO DROP SOUTH ACRS NRN LWR MI THIS EVENING BEFORE EXITING
EAST. EXPECT THE FRONT TO HAVE CLEARED NORTHERN LOWER MICHIGAN
BTWN 03Z AND 06Z. THE ONLY PCPN ASSOCIATED WITH THIS BOUNDARY HAS
BEEN LOCATED RIGHT ALONG THE FRONT...DUE TO THE EXTREMELY DRY AIR
LOCATED OVER THE GREAT LAKES. HOWEVER SFC DEW PTS EVENTUALLY
INCREASED FROM THE TEENS INTO THE MID 20S OVER THE STRAITS AS THE
FRONT APPROACHED (ENOUGH TO GENERATE PCPN). HOWEVER PCPN TYPE AND
CHC OVER THE REST OF THE CWA WILL BE DIFFICULT THIS EVENING AS THE
FRONT DIPS SOUTH. TO THIS POINT...ALL OF THE PCPN HAS BEEN IN THE
FORM OF SNOW OVER ERN UPPER AND THE STRAITS. THE LATEST RUC MODEL
SOUNDINGS SHOW AN INVERTED V SIGNATURE IN THE LOWEST LAYERS FROM
GAYLORD SOUTH TO THE SAGINAW BAY THIS EVENING...WITH OTHERWISE
EXTREMELY DRY AIR ABOVE 850MB. ADDING COMPLICATIONS TO PCPN TYPE
THIS EVENING IS THE VERTICAL TEMP PROFILES...AS MOST OF NRN LWR
WARMED WELL INTO THE MID AND UPPER 40S DUE TO SOUTHWEST WINDS AND
FULL SUN IN ADVANCE OF THE FRONT. HOWEVER PROGGED 850MB WET BULB TEMPS
WOULD SUGGEST ENOUGH EVAP COOLING WITH ONSET OF ADVANCING MSTR TO AT
LEAST MENTION A RAIN/SNOW MIX. OVERALL WILL CONTINUE THE LATEST
TREND OF CHC POPS RAIN/SNOW MIXED OVER THE SRN HALF OF THE CWA AND
SAGINAW BAY INTO THIS EVENING.
COLDER AIR AND NORTHWEST FLOW RE-SETTLES INTO THE REGION OVERNIGHT
AND FRIDAY ON THE BACK SIDE OF THE EXITING BOUNDARY. 850MB TEMPS
QUICKLY DROP FROM ARND -4C THIS EVENING TO BETWEEN -12C AND -14C BY
12Z FRIDAY. SFC-850MB WINDS TURN FROM THE SOUTHWEST THIS EVENING IN
ADVANCE OF THE BOUNDARY TO NNW FRIDAY. MODEL SOUNDINGS SUGGEST INVERSION
HEIGHTS INCREASING TO NEAR 5K FT WHILE LINGERING LOW LVL MSTR EXTENDS
TO AROUND THE -12C ISOTHERM. OVERALL MENTION CHC POPS IN NORTH FLOW
SNOW BELTS EARLY FRIDAY. OTHERWISE WILL MENTION AT LEAST PARTLY
SUNNY SKIES OVER THE REST OF THE CWA FRIDAY. WILL MENTION COOLER AFTN
TEMPS FRIDAY...RANGING FROM AROUND FREEZING OVER ERN UPPER AND THE
STRAITS TO THE LOWER 40S NEAR SAGINAW BAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 344 PM EDT THU APR 4 2013
LITTLE CHANGE FROM WHAT WAS SEEN YESTERDAY...WITH STILL PLENTY OF
POTENTIAL FOR A VERY ACTIVE NEXT 7 DAYS OF WEATHER AS PERSISTENT
-AO RELAXES AND DEEP SOUTHWEST MOISTURE RICH FLOW DEVELOPS ON
FRONTSIDE OF DIGGING INTERMOUNTAIN WEST ENERGY. BIG WILD CARD
REMAINS POTENTIAL INTERACTION WITH POLAR LOW SET TO ROTATE ACROSS
EASTERN CANADA. EVENTUAL PLACEMENT OF THIS FEATURE WILL BE KEY IN
DETERMINING LOCATION OF INTENSE LOW LEVEL THERMAL BOUNDARY AND
SUBSEQUENT PATHWAY FOR ENERGY ROTATING OUT OF WESTERN TROUGH AXIS.
WHILE ABOVE REMAINS A VERY LOW CONFIDENCE PORTION OF THE
FORECAST...LEAD WAVE APPROACHING THE PACIFIC NORTHWEST (NICELY
ILLUSTRATED ON LATEST WATER VAPOR IMAGERY) NOW WELL AGREED UPON TO
IMPACT OUR WEATHER INTO THE START OF THIS WEEKEND. THIS WAVE WILL
BRING ANOTHER BOUT OF WINTRY WEATHER TO THE NORTH WOODS
SATURDAY...WITH INCREASING CONFIDENCE PARTS OF EASTERN UPPER WILL
SEE A PERIOD OF ACCUMULATING SNOW. FORECAST CONCERNS INITIALLY
DEAL WITH THIS LATTER SYSTEM...SPECIFICALLY SNOWFALL ACCUMULATIONS
FOR EASTERN UPPER. MUCH MORE OF PROBABILISTIC APPROACH TAKING FOR
THE REMAINDER OF THE FORECAST...WITH AT LEAST SOME ATTEMPT AT
ADDRESSING MULTI- PERIOD PRECIP CHANCES AND TEMPERATURE TRENDS.
GUIDANCE HAS LOCKED IN A SOLUTION SENDING PACIFIC NORTHWEST WAVE
RAPIDLY EAST INTO THE NORTHERN PLAIN FRIDAY NIGHT...AND THROUGH
NORTHERN MICHIGAN BY SATURDAY NIGHT. WEAKISH COUPLED JET STRUCTURE
AND LOW LEVEL THERMAL BOUNDARY EXPECTED TO ENTICE RESPECTABLE
SURFACE LOW PRESSURE DEVELOPMENT WITH THIS MID LEVEL WAVE...ITSELF
EXPECTED TO SLICE THROUGH THE HEART OF NORTHERN LOWER MICHIGAN
SATURDAY EVENING. ALTHOUGH WAVE ITSELF AND SURFACE FEATURE NOTHING
TO WRITE HOME ABOUT...ACCOMPANYING DYNAMICS REMAIN IMPRESSIVE INDEED.
MULTI-PERIOD TRENDS CONTINUE TO SUPPORT AGGRESSIVE WAA DRIVEN
DYNAMICS...WITH NEAR 60 KNOT SOUTHWEST FLOW LOW LEVEL JET
PERPENDICULAR TO THE 290K-295K PRESSURE SURFACES. DEEP LAYER FGEN
SIGNAL ALSO PRESENT ALONG RETREATING COLD DOME...COLLOCATED NICELY
WITH MAX WAA UPGLIDE ON NOSE OF LOW LEVEL JET. BEST JUXTAPOSITION OF
THE ABOVE EXPECTED ACROSS FAR NORTHERN LOWER AND AREAS NORTH OF THE
BRIDGE SATURDAY INTO SATURDAY EVENING. SYSTEM HAS A NICE SUBTROPICAL
PACIFIC MOISTURE PLUME ALREADY ASSOCIATED WITH IT...SOME OF WHICH
WILL BE ADVECTED INTO OUR AREA AS SYSTEM APPROACHES. COMBINE THIS
WITH BRIEF WINDOW FOR SOME WESTERN GULF OF MEXICO MOISTURE
CONTRIBUTION...AND PWAT VALUES SURGE TO AOA 0.75 INCHES LEVELS BY
LATER SATURDAY. SAID ISENTROPIC SURFACES ALSO SHOW VERY RESPECTABLE
MOISTURE...WITH MIXING RATIOS EXCEEDING 4 G/KG. LITTLE DOUBT SYSTEM
HAS ALL THE EARMARKS TO BE A RATHER SUBSTANTIAL PRECIP PRODUCER...
ALTHOUGH EXACTLY WHAT TYPE THAT PRECIP TAKES REMAINS A FORMIDABLE
CHALLENGE. WILL USE ROCK-STEADY ECMWF DEPICTIONS FOR THERMAL FIELDS.
THIS CONTINUES TO SUGGEST MAINLY SNOW AT THE ONSET EARLY
SATURDAY...RAPIDLY CHANGING OVER TO LIQUID FROM SOUTHWEST TO
NORTHEAST ACROSS NORTHERN LOWER MICHIGAN DURING THE MORNING. COULD
SEE SOME MINOR SNOW ACCUMULATIONS...ON THE ORDER OF AN INCH OR
SO...ESPECIALLY ACROSS THE HIGHER TERRAIN AREAS. WILL NEED TO WATCH
FOR A PERIOD OF FREEZING RAIN AS WAA STRENGTHENS JUST OFF THE DECK.
THIS SHOULD BE SHORT-LIVED EVENT (IF IT OCCURS AT ALL) AND NOT
WORTHY OF A MENTION IN THE FORECAST. MUCH BIGGER PRECIP TYPE
CHALLENGE ACROSS EASTERN UPPER...WITH STRONG DYNAMICS POSSIBLY
OVERCOMING MARGINAL THERMAL PROFILES TO KEEP PRECIP MAINLY ALL
SNOW...ESPECIALLY ALONG AND NORTH OF M-28. MODEL QPF FIELDS SOMEWHAT
DISCONCERTING...WITH PROGS SUPPORTING A HALF INCH OR MORE OF LIQUID
EQUIVALENT PRECIP BY LATER SATURDAY NIGHT. HEAVIER AMOUNTS NO DOUBT
POSSIBLE GIVEN AMOUNT OF EARLIER MENTIONED DYNAMICS. SNOW RATIOS
WILL NOT BE GREAT...ESPECIALLY SATURDAY AFTERNOON...WHEN SURFACE
READINGS WILL LIKELY EXCEED FREEZING AND HIGH APRIL SUN ANGLE TAKES
HOLD. STILL...COULD EASILY SEE SEVERAL INCHES OF HEAVY WET SNOW
ACCUMULATION BY LATER SATURDAY NIGHT...WITH PERIODS OF HIGH
INTENSITY SNOWFALL. NO HEADLINES FORTHCOMING ON THIS SHIFT...BUT IF
ABOVE COMES TO FRUITION...COULD SEE ADVISORY LEVEL SNOW AMOUNTS FOR
AT LEAST PARTS OF EASTERN UPPER. STAY TUNED! SYSTEM WINDS DOWN
QUICKLY LATE SATURDAY NIGHT...LEAVING BEHIND A DRY SUNDAY AND SUNDAY
EVENING.
CONFIDENCE DROPS REMARKABLY HEADING THROUGH NEXT WORK WEEK...WITH
GUIDANCE STRUGGLING WITH KEY INTERACTIONS TALKED ABOUT IN THE LEAD
PARAGRAPH. PLENTY OF POTENTIAL FOR ADDITIONAL SIGNIFICANT
SYSTEMS...WITH SOME DECENT SUPPORT FOR ONE SUCH SYSTEM TO IMPACT OUR
AREA TO KICK OFF THE WEEK. EXACTLY HOW FAR NORTH THIS SYSTEM RIDES UP
THROUGH THE OHIO VALLEY/SOUTHERN LAKES STILL FAR FROM BEING
DETERMINED. DEPENDING ON SUCH...MAY SEE ENOUGH COLD AIR ALONG THE
NORTHERN PERIPHERY OF ITS PRECIP SHIELD TO SUPPORT SOME WINTRY
WEATHER. NO NEED TO GET TOO SPECIFIC...AND WILL BE FORCED TO RUN
WITH A GUIDANCE CONSENSUS BLEND UNTIL A MORE DETERMINISTIC APPROACH
CAN BE UTILIZED. SAME STORY HEADING THROUGH THE REMAINDER OF THE
WEEK...WITH AGAIN THE POTENTIAL FOR ANOTHER WAVE TO ROTATE NORTHEAST
OUT OF THE SOUTHERN PLAINS. TIMING AND PLACEMENT OF SUCH ALL OVER
THE BOARD...AS IT WILL LIKELY REMAIN WITH BAROCLINIC AXIS SUBJECT TO
MANY CHANGES PER CANADIAN TROUGHING AND PASSAGE OF EARLIER IN THE
WEEK SYSTEMS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 700 PM EDT THU APR 4 2013
OVERALL CONDITIONS WILL REMAIN VFR THRU FRIDAY EVENING AS HIGH
PRESSURE...SUBSIDENCE AND DRY AIR SLOWLY BUILD INTO NRN MICHIGAN.
RESIDUAL LOW CLOUDS BEHIND THE COLD FRONT CURRENTLY TRACKING THRU
NRN LWR MICHIGAN WILL DIMINISH THIS EVENING...EXCEPT FOR LOCATIONS
DOWNWIND OF LAKES SUPERIOR AND MICHIGAN UNDER THE DIRECTION OF
N/NW FLOW. A FEW FLURRIES OR LIGHT LAKE SNOW SHOWERS ARE POSSIBLE
FOR TVC AND MBL TONIGHT...BUT CHANCES ARE LOW AND WILL LEAVE OUT
OF THE TAF FOR NOW. N/NW WINDS BEHIND THE COLD FRONT WILL
PERIODICALLY GUST TO 20 KTS.
&&
.MARINE...
ISSUED AT 344 PM EDT THU APR 4 2013
GUSTY SOUTHWEST WINDS IN ADVANCE OF A FRONTAL BOUNDARY DROPPING
SOUTH OVER NRN MI...WILL TURN NORTHWEST OVERNIGHT AND REMAIN BREEZY
ON THE BACKSIDE OF THE EXITING BOUNDARY. RAIN/SNOW MIXED PCPN WILL
AFFECT NRN MI NEARSHORE WATERS THIS EVENING AS BOUNDARY DROPS
SOUTH...WITH SOME LAKE SNOWS POSSIBLE FRIDAY BEHIND THE FRONT.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...MR
SYNOPSIS...KAB
SHORT TERM...SWR
LONG TERM...MSB
AVIATION...MR
MARINE...SWR
AREA FORECAST DISCUSSION
NWS GAYLORD MI
702 PM EDT THU APR 4 2013
.SYNOPSIS...
ISSUED AT 344 PM EDT THU APR 4 2013
A COLD FRONT IS MOVING THROUGH NORTHERN MICHIGAN...BRINGING A
PERIOD OF LIGHT RAIN AND SNOW FOR THIS AFTERNOON AND TONIGHT.
SETTLED WEATHER WILL RETURN FOR A SHORT TIME ON FRIDAY...BEFORE
ANOTHER STORM SYSTEM MOVES INTO NORTHERN MICHIGAN...BRINGING RAIN
AND SNOW MIXED FOR SATURDAY INTO SUNDAY.
&&
.UPDATE...
ISSUED AT 700 PM EDT THU APR 4 2013
LINE OF RAIN/SNOW SHOWERS ACCELERATED SE EARLY THIS EVENING IN
RESPONSE TO A 125 KT 300 MB JET MAX DIGGING INTO THE WRN GREAT
LAKES REGION. HAVE MADE SEVERAL MODIFICATIONS TO TIMING AS A
RESULT...AND ALL PRECIP ASSOCIATED WITH THE FRONT SHOULD CLEAR OUR
CWA WITHIN THE NEXT HOUR OR SO. SOME CLEARING WILL TAKE PLACE...
EXPECT FOR LOCATIONS DOWNSTREAM OF LAKES SUPERIOR AND MICHIGAN
UNDER THE DIRECTION OF N/NW FLOW. LAKE CLOUDS AND SOME
FLURRIES/LIGHT SNOW SHOWERS SHOULD DEVELOP WITHIN THESE AREAS AND
PERSIST THE REST OF THE NIGHT AND INTO FRIDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 344 PM EDT THU APR 4 2013
THE CURRENT RADAR SHOWS A NARROW BAND OF PCPN SLOWLY DROPPING SOUTH
ACROSS NORTHERN LOWER MICHIGAN. THIS NARROW AREA OF PRECIPITATION IS
THE RESULT OF A COLD FRONT SINKING SOUTH OVER THE REGION. VIS SAT
AND SFC OBS SHOW LIMITED MOISTURE EITHER SIDE OF THE BOUNDARY...WITH
MOSTLY SUNNY SKIES OVER MUCH OF CENTRAL AND SOUTHERN MICHIGAN. SUN
OVER THE SRN CWA FROM EARLIER TODAY...HAS ALLOWED AFTERNOON TEMPS IN
THESE AREAS TO WARM QUICKLY INTO THE MID AND UPPER 40S...WHILE
TEMPS REMAIN IN THE 30S OVER ERN UPPER NORTH OF THE BOUNDARY.
OVERALL THE MAIN FORECAST CONCERNS TONIGHT THROUGH FRIDAY WILL BE
TIMING AND TYPE OF PCPN TONIGHT WITH THE APPROACHING FRONT...ALONG
WITH ANY LAKE INDUCED SNOWS FRIDAY ON THE BACKSIDE OF THE COLD
FRONT.
THE STORM SYSTEM CURRENTLY MOVING ACRS ONTARIO WILL QUICKLY EXIT
INTO QUEBEC THIS EVENING. A COLD FRONT ASSOCIATED WITH THIS SYSTEM...
WILL CONT TO DROP SOUTH ACRS NRN LWR MI THIS EVENING BEFORE EXITING
EAST. EXPECT THE FRONT TO HAVE CLEARED NORTHERN LOWER MICHIGAN
BTWN 03Z AND 06Z. THE ONLY PCPN ASSOCIATED WITH THIS BOUNDARY HAS
BEEN LOCATED RIGHT ALONG THE FRONT...DUE TO THE EXTREMELY DRY AIR
LOCATED OVER THE GREAT LAKES. HOWEVER SFC DEW PTS EVENTUALLY
INCREASED FROM THE TEENS INTO THE MID 20S OVER THE STRAITS AS THE
FRONT APPROACHED (ENOUGH TO GENERATE PCPN). HOWEVER PCPN TYPE AND
CHC OVER THE REST OF THE CWA WILL BE DIFFICULT THIS EVENING AS THE
FRONT DIPS SOUTH. TO THIS POINT...ALL OF THE PCPN HAS BEEN IN THE
FORM OF SNOW OVER ERN UPPER AND THE STRAITS. THE LATEST RUC MODEL
SOUNDINGS SHOW AN INVERTED V SIGNATURE IN THE LOWEST LAYERS FROM
GAYLORD SOUTH TO THE SAGINAW BAY THIS EVENING...WITH OTHERWISE
EXTREMELY DRY AIR ABOVE 850MB. ADDING COMPLICATIONS TO PCPN TYPE
THIS EVENING IS THE VERTICAL TEMP PROFILES...AS MOST OF NRN LWR
WARMED WELL INTO THE MID AND UPPER 40S DUE TO SOUTHWEST WINDS AND
FULL SUN IN ADVANCE OF THE FRONT. HOWEVER PROGGED 850MB WET BULB TEMPS
WOULD SUGGEST ENOUGH EVAP COOLING WITH ONSET OF ADVANCING MSTR TO AT
LEAST MENTION A RAIN/SNOW MIX. OVERALL WILL CONTINUE THE LATEST
TREND OF CHC POPS RAIN/SNOW MIXED OVER THE SRN HALF OF THE CWA AND
SAGINAW BAY INTO THIS EVENING.
COLDER AIR AND NORTHWEST FLOW RE-SETTLES INTO THE REGION OVERNIGHT
AND FRIDAY ON THE BACK SIDE OF THE EXITING BOUNDARY. 850MB TEMPS
QUICKLY DROP FROM ARND -4C THIS EVENING TO BETWEEN -12C AND -14C BY
12Z FRIDAY. SFC-850MB WINDS TURN FROM THE SOUTHWEST THIS EVENING IN
ADVANCE OF THE BOUNDARY TO NNW FRIDAY. MODEL SOUNDINGS SUGGEST INVERSION
HEIGHTS INCREASING TO NEAR 5K FT WHILE LINGERING LOW LVL MSTR EXTENDS
TO AROUND THE -12C ISOTHERM. OVERALL MENTION CHC POPS IN NORTH FLOW
SNOW BELTS EARLY FRIDAY. OTHERWISE WILL MENTION AT LEAST PARTLY
SUNNY SKIES OVER THE REST OF THE CWA FRIDAY. WILL MENTION COOLER AFTN
TEMPS FRIDAY...RANGING FROM AROUND FREEZING OVER ERN UPPER AND THE
STRAITS TO THE LOWER 40S NEAR SAGINAW BAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 344 PM EDT THU APR 4 2013
LITTLE CHANGE FROM WHAT WAS SEEN YESTERDAY...WITH STILL PLENTY OF
POTENTIAL FOR A VERY ACTIVE NEXT 7 DAYS OF WEATHER AS PERSISTENT
-AO RELAXES AND DEEP SOUTHWEST MOISTURE RICH FLOW DEVELOPS ON
FRONTSIDE OF DIGGING INTERMOUNTAIN WEST ENERGY. BIG WILD CARD
REMAINS POTENTIAL INTERACTION WITH POLAR LOW SET TO ROTATE ACROSS
EASTERN CANADA. EVENTUAL PLACEMENT OF THIS FEATURE WILL BE KEY IN
DETERMINING LOCATION OF INTENSE LOW LEVEL THERMAL BOUNDARY AND
SUBSEQUENT PATHWAY FOR ENERGY ROTATING OUT OF WESTERN TROUGH AXIS.
WHILE ABOVE REMAINS A VERY LOW CONFIDENCE PORTION OF THE
FORECAST...LEAD WAVE APPROACHING THE PACIFIC NORTHWEST (NICELY
ILLUSTRATED ON LATEST WATER VAPOR IMAGERY) NOW WELL AGREED UPON TO
IMPACT OUR WEATHER INTO THE START OF THIS WEEKEND. THIS WAVE WILL
BRING ANOTHER BOUT OF WINTRY WEATHER TO THE NORTH WOODS
SATURDAY...WITH INCREASING CONFIDENCE PARTS OF EASTERN UPPER WILL
SEE A PERIOD OF ACCUMULATING SNOW. FORECAST CONCERNS INITIALLY
DEAL WITH THIS LATTER SYSTEM...SPECIFICALLY SNOWFALL ACCUMULATIONS
FOR EASTERN UPPER. MUCH MORE OF PROBABILISTIC APPROACH TAKING FOR
THE REMAINDER OF THE FORECAST...WITH AT LEAST SOME ATTEMPT AT
ADDRESSING MULTI- PERIOD PRECIP CHANCES AND TEMPERATURE TRENDS.
GUIDANCE HAS LOCKED IN A SOLUTION SENDING PACIFIC NORTHWEST WAVE
RAPIDLY EAST INTO THE NORTHERN PLAIN FRIDAY NIGHT...AND THROUGH
NORTHERN MICHIGAN BY SATURDAY NIGHT. WEAKISH COUPLED JET STRUCTURE
AND LOW LEVEL THERMAL BOUNDARY EXPECTED TO ENTICE RESPECTABLE
SURFACE LOW PRESSURE DEVELOPMENT WITH THIS MID LEVEL WAVE...ITSELF
EXPECTED TO SLICE THROUGH THE HEART OF NORTHERN LOWER MICHIGAN
SATURDAY EVENING. ALTHOUGH WAVE ITSELF AND SURFACE FEATURE NOTHING
TO WRITE HOME ABOUT...ACCOMPANYING DYNAMICS REMAIN IMPRESSIVE INDEED.
MULTI-PERIOD TRENDS CONTINUE TO SUPPORT AGGRESSIVE WAA DRIVEN
DYNAMICS...WITH NEAR 60 KNOT SOUTHWEST FLOW LOW LEVEL JET
PERPENDICULAR TO THE 290K-295K PRESSURE SURFACES. DEEP LAYER FGEN
SIGNAL ALSO PRESENT ALONG RETREATING COLD DOME...COLLOCATED NICELY
WITH MAX WAA UPGLIDE ON NOSE OF LOW LEVEL JET. BEST JUXTAPOSITION OF
THE ABOVE EXPECTED ACROSS FAR NORTHERN LOWER AND AREAS NORTH OF THE
BRIDGE SATURDAY INTO SATURDAY EVENING. SYSTEM HAS A NICE SUBTROPICAL
PACIFIC MOISTURE PLUME ALREADY ASSOCIATED WITH IT...SOME OF WHICH
WILL BE ADVECTED INTO OUR AREA AS SYSTEM APPROACHES. COMBINE THIS
WITH BRIEF WINDOW FOR SOME WESTERN GULF OF MEXICO MOISTURE
CONTRIBUTION...AND PWAT VALUES SURGE TO AOA 0.75 INCHES LEVELS BY
LATER SATURDAY. SAID ISENTROPIC SURFACES ALSO SHOW VERY RESPECTABLE
MOISTURE...WITH MIXING RATIOS EXCEEDING 4 G/KG. LITTLE DOUBT SYSTEM
HAS ALL THE EARMARKS TO BE A RATHER SUBSTANTIAL PRECIP PRODUCER...
ALTHOUGH EXACTLY WHAT TYPE THAT PRECIP TAKES REMAINS A FORMIDABLE
CHALLENGE. WILL USE ROCK-STEADY ECMWF DEPICTIONS FOR THERMAL FIELDS.
THIS CONTINUES TO SUGGEST MAINLY SNOW AT THE ONSET EARLY
SATURDAY...RAPIDLY CHANGING OVER TO LIQUID FROM SOUTHWEST TO
NORTHEAST ACROSS NORTHERN LOWER MICHIGAN DURING THE MORNING. COULD
SEE SOME MINOR SNOW ACCUMULATIONS...ON THE ORDER OF AN INCH OR
SO...ESPECIALLY ACROSS THE HIGHER TERRAIN AREAS. WILL NEED TO WATCH
FOR A PERIOD OF FREEZING RAIN AS WAA STRENGTHENS JUST OFF THE DECK.
THIS SHOULD BE SHORT-LIVED EVENT (IF IT OCCURS AT ALL) AND NOT
WORTHY OF A MENTION IN THE FORECAST. MUCH BIGGER PRECIP TYPE
CHALLENGE ACROSS EASTERN UPPER...WITH STRONG DYNAMICS POSSIBLY
OVERCOMING MARGINAL THERMAL PROFILES TO KEEP PRECIP MAINLY ALL
SNOW...ESPECIALLY ALONG AND NORTH OF M-28. MODEL QPF FIELDS SOMEWHAT
DISCONCERTING...WITH PROGS SUPPORTING A HALF INCH OR MORE OF LIQUID
EQUIVALENT PRECIP BY LATER SATURDAY NIGHT. HEAVIER AMOUNTS NO DOUBT
POSSIBLE GIVEN AMOUNT OF EARLIER MENTIONED DYNAMICS. SNOW RATIOS
WILL NOT BE GREAT...ESPECIALLY SATURDAY AFTERNOON...WHEN SURFACE
READINGS WILL LIKELY EXCEED FREEZING AND HIGH APRIL SUN ANGLE TAKES
HOLD. STILL...COULD EASILY SEE SEVERAL INCHES OF HEAVY WET SNOW
ACCUMULATION BY LATER SATURDAY NIGHT...WITH PERIODS OF HIGH
INTENSITY SNOWFALL. NO HEADLINES FORTHCOMING ON THIS SHIFT...BUT IF
ABOVE COMES TO FRUITION...COULD SEE ADVISORY LEVEL SNOW AMOUNTS FOR
AT LEAST PARTS OF EASTERN UPPER. STAY TUNED! SYSTEM WINDS DOWN
QUICKLY LATE SATURDAY NIGHT...LEAVING BEHIND A DRY SUNDAY AND SUNDAY
EVENING.
CONFIDENCE DROPS REMARKABLY HEADING THROUGH NEXT WORK WEEK...WITH
GUIDANCE STRUGGLING WITH KEY INTERACTIONS TALKED ABOUT IN THE LEAD
PARAGRAPH. PLENTY OF POTENTIAL FOR ADDITIONAL SIGNIFICANT
SYSTEMS...WITH SOME DECENT SUPPORT FOR ONE SUCH SYSTEM TO IMPACT OUR
AREA TO KICK OFF THE WEEK. EXACTLY HOW FAR NORTH THIS SYSTEM RIDES UP
THROUGH THE OHIO VALLEY/SOUTHERN LAKES STILL FAR FROM BEING
DETERMINED. DEPENDING ON SUCH...MAY SEE ENOUGH COLD AIR ALONG THE
NORTHERN PERIPHERY OF ITS PRECIP SHIELD TO SUPPORT SOME WINTRY
WEATHER. NO NEED TO GET TOO SPECIFIC...AND WILL BE FORCED TO RUN
WITH A GUIDANCE CONSENSUS BLEND UNTIL A MORE DETERMINISTIC APPROACH
CAN BE UTILIZED. SAME STORY HEADING THROUGH THE REMAINDER OF THE
WEEK...WITH AGAIN THE POTENTIAL FOR ANOTHER WAVE TO ROTATE NORTHEAST
OUT OF THE SOUTHERN PLAINS. TIMING AND PLACEMENT OF SUCH ALL OVER
THE BOARD...AS IT WILL LIKELY REMAIN WITH BAROCLINIC AXIS SUBJECT TO
MANY CHANGES PER CANADIAN TROUGHING AND PASSAGE OF EARLIER IN THE
WEEK SYSTEMS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 700 PM EDT THU APR 4 2013
OVERALL CONDITIONS WILL REMAIN VFR THRU FRIDAY EVENING AS HIGH
PRESSURE...SUBSIDENCE AND DRY AIR SLOWLY BUILD INTO NRN MICHIGAN.
RESIDUAL LOW CLOUDS BEHIND THE COLD FRONT CURRENTLY TRACKING THRU
NRN LWR MICHIGAN WILL DIMINISH THIS EVENING...EXCEPT FOR LOCATIONS
DOWNWIND OF LAKES SUPERIOR AND MICHIGAN UNDER THE DIRECTION OF
N/NW FLOW. A FEW FLURRIES OR LIGHT LAKE SNOW SHOWERS ARE POSSIBLE
FOR TVC AND MBL TONIGHT...BUT CHANCES ARE LOW AND WILL LEAVE OUT
OF THE TAF FOR NOW. N/NW WINDS BEHIND THE COLD FRONT WILL
PERIODICALLY GUST TO 20 KTS.
&&
.MARINE...
ISSUED AT 344 PM EDT THU APR 4 2013
GUSTY SOUTHWEST WINDS IN ADVANCE OF A FRONTAL BOUNDARY DROPPING
SOUTH OVER NRN MI...WILL TURN NORTHWEST OVERNIGHT AND REMAIN BREEZY
ON THE BACKSIDE OF THE EXITING BOUNDARY. RAIN/SNOW MIXED PCPN WILL
AFFECT NRN MI NEARSHORE WATERS THIS EVENING AS BOUNDARY DROPS
SOUTH...WITH SOME LAKE SNOWS POSSIBLE FRIDAY BEHIND THE FRONT.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 8 AM EDT FRIDAY FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT FRIDAY FOR LMZ323-341-342-
344>346.
LS...SMALL CRAFT ADVISORY UNTIL 8 AM EDT FRIDAY FOR LSZ321-322.
&&
$$
UPDATE...MR
SYNOPSIS...KAB
SHORT TERM...SWR
LONG TERM...MSB
AVIATION...MR
MARINE...SWR
AREA FORECAST DISCUSSION
NWS BILLINGS MT
314 PM MDT WED APR 3 2013
.SHORT TERM...VALID FOR THU AND FRI...
COLD FRONT HAD PUSHED THROUGH THE FRONT RANGE OF MONTANA BY EARLY
AFTERNOON AND IS CHUGGING ALONG PRETTY GOOD. I LIKE THE RAP MODELS
TIMING WHICH SWITCHES BILLINGS WINDS TO THE NORTHEAST LATE THIS
AFTERNOON AND SHERIDANS BY 8 PM. THE RAP ALSO BRINGS EASTERLY WIND
INTO LIVINGSTON AT THAT POINT...BUT WE ARE LESS CONFIDENT IN THIS
OCCURRING...AND BELIEVE THE COOLER AIR MIGHT STAY JUST EAST OF
LIVINGSTON DOORSTEP. AT ANY RATE MODELS ARE GENERATING DECENT
FRONTOGENESIS OVER OUR WESTERN ZONES LATE TODAY AND THERE APPEARS
TO BE SOME MODEST CONVECTION DEVELOPING JUST UPSTREAM OF THIS
AREA. SOME WEAK ENERGY CONTINUES TO MOVE ACROSS EAST CENTRAL
MONTANA OVERNIGHT...SO WILL CONTINUE TO INCLUDE SOME LOW POPS
AFTER MIDNIGHT.
THURSDAY OUR FORECAST AREA WILL GENERALLY BE BETWEEN SYSTEMS WITH
LOW AMPLITUDE RIDGING AND SURFACE TROUGHING DEVELOPING BEFORE
EVENING. THE MAIN WEATHER FEATURE THURSDAY WILL BE THE BACKING
UPPER FLOW BRINGING A NICE FETCH OF PACIFIC MOISTURE INTO THE
INNER ROCKIES. SO WE EXPECT INCREASING CLOUD COVER TO LIMIT
TEMPERATURES AND MIXING SOMEWHAT. BY THURSDAY NIGHT...WEAK ENERGY
INVOLVED WITH THAT MOISTURE FETCH MAY SPREAD SOME LIGHT SHOWERS
ACROSS THE REGION. HOWEVER THE MAIN PLAYER CONTINUES TO BE A LOW
AMPLITUDE SHORT WAVE PROGGED TO CROSS OUR FORECAST AREA FRIDAY.
MODELS AGREE THAT Q VECTOR FORCING WILL BE RIGHT OVER OUR ZONES
FRIDAY AFTERNOON WITH DECENT CAPE ON THE ORDER FROM 200-400 JL/KG.
I CONTINUED TO NUDGE THE POPS UP FOR FRIDAY AFTERNOON IN MANY
LOCATIONS AND WENT CATEGORICAL IN THE HIGH COUNTRY. THE GFS
LINGERS QPF OVER OUR FORECAST AREA WELL INTO FRIDAY NIGHT...BUT
THE OVERALL CONSENSUS OF MODELS GENERALLY EXIT THIS FORCING TO
THE EAST IN THE EVENING. THIS SEEMS MORE LIKELY GIVEN THE GOOD
CONVERGENT/DIVERGENT COUPLET...SO TRENDED OUR POPS LOWER
OVERNIGHT. BT
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
FAIRLY ACTIVE AND SPRING-LIKE WEATHER PATTERN SHAPING UP FOR THE
EXTENDED PERIOD...THOUGH LATEST MODELS HAVE SHIFTED A BIT FOR THE
MON/TUE TIME FRAME.
SATURDAY STILL LOOKING FAIRLY QUIET WITH RIDGING BEHIND LATE
FRIDAY WAVE. HAVE REDUCED POPS FOR ALL BUT OUR WEST...WHICH
SHOULD BEGIN TO SEE INCREASED SHOWER ACTIVITY BY AFTERNOON...AND
PER WESTERLY DOWNSLOPE WINDS HAVE ALSO RAISED TEMPS A FEW DEGREES.
SHOULD SEE HIGHS INTO THE LOWER/MID 60S.
MODELS CONTINUE TO BE IN GOOD AGREEMENT WITH TIMING A SHORTWAVE
THROUGH THE REGION SATURDAY NIGHT. WITH INCREASING CONFIDENCE HAVE
RAISED POPS A BIT MORE...TO LIKELY IN CENTRAL AND EAST PARTS AWAY
FROM THE DOWNSLOPING WESTERN FOOTHILLS. AIRMASS LOOKS TO BE TOO
WARM FOR ANYTHING BUT RAIN SHOWERS AT OUR LOWER ELEVATIONS...WITH
A POSSIBLE EXCEPTION IN OUR FAR NE WHERE LOW LEVEL EAST WINDS MAY
KEEP 850MB TEMPS NEAR ZERO. SO WILL KEEP A RAIN/SNOW MIX WITH
JUST A LITTLE ACCUMULATION FROM MILES CITY TO BAKER...BUT THE
BETTER SNOW POTENTIAL REALLY SHOULD BE NORTH AND NORTHEAST OF OUR
CWA. SYSTEM WILL EXIT QUICKLY INTO THE DAKOTAS AROUND 12Z SUNDAY.
NEXT PACIFIC ENERGY WILL BEGIN TO INFLUENCE OUR WEST BY SUNDAY
AFTERNOON OR NIGHT...SOME TIMING ISSUES EXIST HERE. THEN...AS
PREVIOUSLY MENTIONED...MODELS ARE BEGINNING TO PAINT A DIFFERENT
PICTURE WITH EVOLUTION OF THIS SYSTEM INTO MON/TUE. FLOW IN THE
EASTERN PACIFIC NOW EXPECTED TO BE A BIT FLATTER...WITH
AMPLIFICATION OVER THE WESTERN CONUS SHIFTED A BIT EAST. THUS...
PER LATEST TRENDS...A LARGE CLOSED LOW OVER THE GREAT BASIN TO
4-CORNERS REGION NOW LOOKS LESS LIKELY...WHICH LEAVES A WNW FLOW
WITH LOWER HEIGHTS OVER OUR REGION AS ENERGY DRIVES TO THE CENTRAL
ROCKIES AND MIDDLE PLAINS. COULD STILL SEE SOME WET SNOW IMPACTS
IN OUR AREA SOMETIME IN THE SUNDAY NIGHT INTO TUESDAY TIME
FRAME...AND BOTH THE GFS AND EC SHOW 850MB TEMPS NEAR OR SLIGHTLY
BELOW ZERO...BUT OVERALL POTENTIAL APPEARS LOWER NOW. PROGRESSIVE
SHORTWAVE ENERGY IN LOW HEIGHT REGIME AND LOW LEVEL UPSLOPE FLOW
ALL COMBINE TO WARRANT ABOVE CLIMO POPS FOR US NONETHELESS. WILL
TAPER POPS TO BELOW CLIMO...SLIGHT CHANCE...BY WEDNESDAY AS MODEL
CONSENSUS IS FOR RISING HEIGHTS WITH RIDGE BEGINNING TO BUILD OVER
THE PAC NW BY THEN.
AS FOR TEMPERATURES...ABOVE NORMAL SATURDAY SHOULD COOL TO NEAR
NORMAL SUNDAY AND BELOW NORMAL MONDAY AND TUESDAY. COULD SEE A
RETURN TO NEAR OR ABOVE NORMAL TEMPS BY THE MIDDLE OF NEXT WEEK...
AND HAVE ADJUSTED GRIDS ACCORDINGLY.
JKL
&&
.AVIATION...
A CANADIAN COLD FRONT IS PUSHING SOUTHWARD THROUGH THE AREA THIS
AFTERNOON...CAUSING GUSTY NW-N-NE WINDS ACROSS THE LOWER
ELEVATIONS...WITH GUSTS TO 25 KTS UNTIL SUNSET. EXPECT ISOLATED TO
SCATTERED SHOWERS TO DEVELOP ALONG THIS FRONTAL BOUNDARY FROM KLVM
TO KBIL AND KSHR THROUGH AROUND 04Z...WITH DRYING ANTICIPATED
LATER TONIGHT. LOCALIZED MVFR IS POSSIBLE WITH THE SHOWER
ACTIVITY. VFR CONDITIONS WILL PREVAIL ACROSS THE AREA LATE TONIGHT
AND THURSDAY. JKL
&&
.PRELIMINARY POINT TEMP/POPS...
THU FRI SAT SUN MON TUE WED
-----------------------------------------------------------
BIL 034/064 043/064 038/063 038/057 032/046 029/048 030/056
20/B 37/T 32/W 52/W 35/W 42/W 22/W
LVM 033/064 039/058 033/061 031/055 029/044 028/046 028/055
31/B 26/T 24/W 53/W 35/J 32/W 22/W
HDN 033/065 041/068 038/065 036/059 031/047 029/049 028/054
20/B 37/T 32/W 62/W 35/W 42/W 22/W
MLS 031/057 038/067 038/061 035/055 029/045 027/045 026/049
32/W 24/T 31/B 62/W 24/W 42/W 22/W
4BQ 031/064 040/066 038/062 036/056 032/046 028/044 024/046
21/B 14/T 41/B 63/W 24/W 43/W 22/W
BHK 027/050 032/061 035/055 031/050 027/041 023/041 023/043
33/W 13/T 31/B 64/W 33/W 33/J 22/W
SHR 032/064 039/066 035/061 033/056 030/045 027/045 027/051
20/B 14/T 31/B 32/W 35/W 43/W 22/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1248 PM CDT WED APR 3 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 314 AM CDT WED APR 3 2013
THE RAP...NAM AND GFS ARE SUGGESTING SUFFICIENT LOW AND MID LEVEL
CLOUDINESS ACROSS SRN NEB TO HOLD TEMPS IN THE 50S TODAY. AT THE
SAME TIME SOUTH AND SOUTHWEST WINDS WILL RECIRCULATE COOL AIR NORTH
FROM THE HIGH PRESSURE SYSTEM ACROSS THE MID SOUTH. SO THE RAP 21Z
TEMPS WERE USED AS THE BASIS FOR TODAYS HIGHS WHICH IS CLOSE TO THE
GUIDANCE DATA SETS. IF FULL SUN ARRIVES OR EVEN JUST HIGH LEVEL
CLOUDINESS...HIGHS COULD BE A FEW DEGREES WARMER.
THE BEST GUESS ON TONIGHTS LOWS IS FOR THE CLOUDS TO DEPART WITH
WEAK SFC WINDS DEVELOPING AHEAD OF A COLD FRONT MOVING THROUGH SOUTH
DAKOTA WHICH WOULD SUPPORT SOME RADIATIONAL COOLING ACROSS NEB. LOWS
IN THE UPPER 20S TO MID 30S APPEARS TO BE THE BEST FORECAST.
ADDITIONAL COOLING FROM THE DROUGHT CONDITIONS COULD PUSH LOWS
FURTHER.
THE REST OF THE FCST IS WELL BEHAVED. WINDS COULD REACH THE BREEZY
CATEGORY BUT RELATIVE HUMIDITY WILL RUN 25 TO 30 PERCENT. THE RAP
SUGGESTED LOWER RH ACROSS FAR NORTHWEST NEB AS THE FRONT NOSES SOUTH
LATE THIS AFTN BUT AT THE SAME TIME WINDS WEAKEN.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 314 AM CDT WED APR 3 2013
12Z THURSDAY AND BEYOND. TWO MAIN CONCERNS GOING IN
THE EXTENDED PERIOD. FIRST BEING THE POTENTIAL FOR FIRE HEADLINES
ON FRIDAY...THEREAFTER THE FOCUS TURNS TO THE DEVELOPMENT OF A
WESTERN CONUS TROUGH...WHICH MAY BRING PERIODS OF WIDESPREAD
PRECIPITATION BACK ACROSS THE FORECAST AREA LATE THIS WEEKEND
THROUGH EARLY NEXT WEEK.
SURFACE TEMPERATURES WILL SLOWLY MODERATE FROM WEST TO EAST ON
THURSDAY AS SURFACE HIGH PRESSURE SLOWLY BUILDS EAST ACROSS THE
NORTHERN PLAINS AND ALLOWS FOR A RETURN SOUTHERLY FLOW. A TIGHT
GRADIENT IS EXPECTED IN THE TEMPERATURE FIELD...WITH HIGHS POSSIBLY
APPROACHING 70 ACROSS SOUTHWEST NEBRASKA...BUT READINGS OF ONLY THE
LOW TO MID 50S OVER NORTH CENTRAL NEBRASKA. FOR FRIDAY...THE
NORTHERN PLAINS HIGH WILL BE LOCATED OVER THE GREAT LAKES REGION
WITH STRONG SOUTHERLY RETURN FLOW TARGETING THE ENTIRE FORECAST
AREA. WITH DEEPENING LOW PRESSURE ON THE LEE OF THE ROCKIES...A
TIGHT PRESSURE GRADIENT IS EXPECTED...WITH THE POTENTIAL FOR WIND
GUSTS IN EXCESS OF 25 MPH. MEANWHILE SFC TEMPERATURE AND DEW POINT
SPREADS WILL APPROACH 40 F...WHICH SHOULD LEAD TO LOCALIZED AREAS OF
SUB 20 PERCENT RH. GIVEN THAT GREEN UP HAS NOT YET
OCCURRED...LOCALIZED RED FLAG CONDITIONS ARE POSSIBLE. UNCERTAINTY
REMAINS IF THE RED FLAG CRITERIA WIND GUSTS WILL BE CO-LOCATED
WITHIN THE CRITICAL RH FIELD. AT THIS TIME...IT APPEARS THAT THE
STRONGEST GUSTS SHOULD OCCUR OVER EASTERN PORTIONS OF THE
CWA...WHERE THE SOUTHERLY FLOW SHOULD HELP PUSH TD/S UP NEAR
40...WHICH WOULD KEEP MINIMUM RH IN THE 20-30 PERCENT RANGE. THE
DRIEST AIR IS EXPECTED ACROSS THE WESTERN HALF OF THE CWA...SLIGHTLY
REMOVED FROM THE STRONGEST GUSTS. OBVIOUSLY THERE IS STILL TIME TO
HAMMER OUT THE DETAILS...BUT GIVEN A FAVORABLE FIRE WX PATTERN
/RIDGE BREAKDOWN/ AND THE FACT THAT WIND SHIFT IS EXPECTED LATE
AFTERNOON/EVENING AS A SURFACE TROUGH AND COLD FRONT ADVANCE EAST
ACROSS THE CWA...ITS SAFE TO SAY AT THIS JUNCTURE THAT ELEVATED FIRE
CONCERNS ARE CERTAINLY WARRANTED...WILL CONTINUE TO MONITOR. ALSO
OF CONCERN...PROXIMITY SOUNDINGS INDICATE WEAK INSTABILITY ALONG THE
FRONTAL PASSAGE...BUT DRY LOWER LEVELS...A FEW DRIER CG STRIKES COULD
OCCUR. OTHERWISE HIGH TEMPERATURES WILL COOL SOME TEN DEGREES FROM
THE MID 70S DOWN TO THE UPPER 50S TO MID 60S ON SATURDAY. LOWS
FRIDAY AND SATURDAY MORNING WILL BE MILD RELATIVELY SPEAKING...WITH
LOWS IN THE 30S FRIDAY...AND LOWS IN THE 40S SATURDAY MORNING.
ATTENTION NOW TURNS TO THE MYRIAD OF POTENTIAL WEATHER FOR LATE
SUNDAY THROUGH EARLY NEXT WEEK...BUT UNFORTUNATELY THE 03.00Z RUN OF
THE MODELS FAILED TO INCREASE FORECAST CONFIDENCE AS SIGNIFICANT
DIFFERENCES IN TIMING AND STRENGTH OF THE WESTERN CONUS TROUGH
EXISTS. THE GENERAL IDEA IS THAT A SHORTWAVE WILL CROSS THE
CENTRAL/NORTHERN PLAINS ON SUNDAY PROVIDING FOR SHOWERS AND/OR
TSTMS...THEN THE MEAN TROUGH WILL DEVELOP OVER THE ROCKIES AND
SLOWLY ADVANCE OUT ONTO THE PLAINS EARLY NEXT WEEK. THE EC SOLUTION
CONTINUES TO ADVERTISE ENOUGH COLD AIR ON THE BACK SIDE OF THE MAIN
H5 LOW TO ALLOW FOR SNOW ACCUMULATIONS...WHICH MAY BE SIGNIFICANT.
ALSO OF NOTE...THE EC DEVELOPS H85 WINDS IN EXCESS OF 60KTS EARLY
TUESDAY ACROSS EASTERN PORTIONS OF THE CWA. THE EURO HAS SHOWN A
COLD BIAS WITH IT/S LAST STORM THAT AFFECTED OUR CWA...SO THE AMOUNT
OF COOLING IS SUSPECT. THE GFS IS SHOWING A BIT MORE OF A SOUTHERLY
TRACK OF THE MEAN TROUGH...AND IS LESS NEGATIVELY TILTED...BUT THE
GFS ENSEMBLE MEAN GIVES SUPPORT TO THE EC SOLUTION. AS STATED
PREVIOUSLY...CONFIDENCE IN ANY PARTICULAR SOLUTION IS LOW...THUS
WILL MAINTAIN 40 PERCENT POPS OR LESS THROUGH THE EVENT AND KEEP THE
GENERAL IDEA OF SHOWERS OF RAIN INITIALLY...THEN POSSIBLY CHANGING
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1243 PM CDT WED APR 3 2013
UPPER LEVEL LOW PRESSURE SYSTEM CONTINUES TO MOVE SLOWLY EAST
ACROSS KS. SOME MID AND HIGH LEVEL CLOUDS HAVE SPREAD INTO
SOUTHWEST NEBRASKA WITH THIS SYSTEM. OTHERWISE A BRISK SOUTH TO
SOUTHWEST WIND...WITH GUSTS OF 25 TO 30 KTS WILL CONTINUE THROUGH
THE AFTERNOON. WINDS WILL DECREASE TONIGHT WITH CONTINUE VFR.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
622 AM CDT WED APR 3 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 314 AM CDT WED APR 3 2013
THE RAP...NAM AND GFS ARE SUGGESTING SUFFICIENT LOW AND MID LEVEL
CLOUDINESS ACROSS SRN NEB TO HOLD TEMPS IN THE 50S TODAY. AT THE
SAME TIME SOUTH AND SOUTHWEST WINDS WILL RECIRCULATE COOL AIR NORTH
FROM THE HIGH PRESSURE SYSTEM ACROSS THE MID SOUTH. SO THE RAP 21Z
TEMPS WERE USED AS THE BASIS FOR TODAYS HIGHS WHICH IS CLOSE TO THE
GUIDANCE DATA SETS. IF FULL SUN ARRIVES OR EVEN JUST HIGH LEVEL
CLOUDINESS...HIGHS COULD BE A FEW DEGREES WARMER.
THE BEST GUESS ON TONIGHTS LOWS IS FOR THE CLOUDS TO DEPART WITH
WEAK SFC WINDS DEVELOPING AHEAD OF A COLD FRONT MOVING THROUGH SOUTH
DAKOTA WHICH WOULD SUPPORT SOME RADIATIONAL COOLING ACROSS NEB. LOWS
IN THE UPPER 20S TO MID 30S APPEARS TO BE THE BEST FORECAST.
ADDITIONAL COOLING FROM THE DROUGHT CONDITIONS COULD PUSH LOWS
FURTHER.
THE REST OF THE FCST IS WELL BEHAVED. WINDS COULD REACH THE BREEZY
CATEGORY BUT RELATIVE HUMIDITY WILL RUN 25 TO 30 PERCENT. THE RAP
SUGGESTED LOWER RH ACROSS FAR NORTHWEST NEB AS THE FRONT NOSES SOUTH
LATE THIS AFTN BUT AT THE SAME TIME WINDS WEAKEN.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 314 AM CDT WED APR 3 2013
12Z THURSDAY AND BEYOND. TWO MAIN CONCERNS GOING IN
THE EXTENDED PERIOD. FIRST BEING THE POTENTIAL FOR FIRE HEADLINES
ON FRIDAY...THEREAFTER THE FOCUS TURNS TO THE DEVELOPMENT OF A
WESTERN CONUS TROUGH...WHICH MAY BRING PERIODS OF WIDESPREAD
PRECIPITATION BACK ACROSS THE FORECAST AREA LATE THIS WEEKEND
THROUGH EARLY NEXT WEEK.
SURFACE TEMPERATURES WILL SLOWLY MODERATE FROM WEST TO EAST ON
THURSDAY AS SURFACE HIGH PRESSURE SLOWLY BUILDS EAST ACROSS THE
NORTHERN PLAINS AND ALLOWS FOR A RETURN SOUTHERLY FLOW. A TIGHT
GRADIENT IS EXPECTED IN THE TEMPERATURE FIELD...WITH HIGHS POSSIBLY
APPROACHING 70 ACROSS SOUTHWEST NEBRASKA...BUT READINGS OF ONLY THE
LOW TO MID 50S OVER NORTH CENTRAL NEBRASKA. FOR FRIDAY...THE
NORTHERN PLAINS HIGH WILL BE LOCATED OVER THE GREAT LAKES REGION
WITH STRONG SOUTHERLY RETURN FLOW TARGETING THE ENTIRE FORECAST
AREA. WITH DEEPENING LOW PRESSURE ON THE LEE OF THE ROCKIES...A
TIGHT PRESSURE GRADIENT IS EXPECTED...WITH THE POTENTIAL FOR WIND
GUSTS IN EXCESS OF 25 MPH. MEANWHILE SFC TEMPERATURE AND DEW POINT
SPREADS WILL APPROACH 40 F...WHICH SHOULD LEAD TO LOCALIZED AREAS OF
SUB 20 PERCENT RH. GIVEN THAT GREEN UP HAS NOT YET
OCCURRED...LOCALIZED RED FLAG CONDITIONS ARE POSSIBLE. UNCERTAINTY
REMAINS IF THE RED FLAG CRITERIA WIND GUSTS WILL BE CO-LOCATED
WITHIN THE CRITICAL RH FIELD. AT THIS TIME...IT APPEARS THAT THE
STRONGEST GUSTS SHOULD OCCUR OVER EASTERN PORTIONS OF THE
CWA...WHERE THE SOUTHERLY FLOW SHOULD HELP PUSH TD/S UP NEAR
40...WHICH WOULD KEEP MINIMUM RH IN THE 20-30 PERCENT RANGE. THE
DRIEST AIR IS EXPECTED ACROSS THE WESTERN HALF OF THE CWA...SLIGHTLY
REMOVED FROM THE STRONGEST GUSTS. OBVIOUSLY THERE IS STILL TIME TO
HAMMER OUT THE DETAILS...BUT GIVEN A FAVORABLE FIRE WX PATTERN
/RIDGE BREAKDOWN/ AND THE FACT THAT WIND SHIFT IS EXPECTED LATE
AFTERNOON/EVENING AS A SURFACE TROUGH AND COLD FRONT ADVANCE EAST
ACROSS THE CWA...ITS SAFE TO SAY AT THIS JUNCTURE THAT ELEVATED FIRE
CONCERNS ARE CERTAINLY WARRANTED...WILL CONTINUE TO MONITOR. ALSO
OF CONCERN...PROXIMITY SOUNDINGS INDICATE WEAK INSTABILITY ALONG THE
FRONTAL PASSAGE...BUT DRY LOWER LEVELS...A FEW DRIER CG STRIKES COULD
OCCUR. OTHERWISE HIGH TEMPERATURES WILL COOL SOME TEN DEGREES FROM
THE MID 70S DOWN TO THE UPPER 50S TO MID 60S ON SATURDAY. LOWS
FRIDAY AND SATURDAY MORNING WILL BE MILD RELATIVELY SPEAKING...WITH
LOWS IN THE 30S FRIDAY...AND LOWS IN THE 40S SATURDAY MORNING.
ATTENTION NOW TURNS TO THE MYRIAD OF POTENTIAL WEATHER FOR LATE
SUNDAY THROUGH EARLY NEXT WEEK...BUT UNFORTUNATELY THE 03.00Z RUN OF
THE MODELS FAILED TO INCREASE FORECAST CONFIDENCE AS SIGNIFICANT
DIFFERENCES IN TIMING AND STRENGTH OF THE WESTERN CONUS TROUGH
EXISTS. THE GENERAL IDEA IS THAT A SHORTWAVE WILL CROSS THE
CENTRAL/NORTHERN PLAINS ON SUNDAY PROVIDING FOR SHOWERS AND/OR
TSTMS...THEN THE MEAN TROUGH WILL DEVELOP OVER THE ROCKIES AND
SLOWLY ADVANCE OUT ONTO THE PLAINS EARLY NEXT WEEK. THE EC SOLUTION
CONTINUES TO ADVERTISE ENOUGH COLD AIR ON THE BACK SIDE OF THE MAIN
H5 LOW TO ALLOW FOR SNOW ACCUMULATIONS...WHICH MAY BE SIGNIFICANT.
ALSO OF NOTE...THE EC DEVELOPS H85 WINDS IN EXCESS OF 60KTS EARLY
TUESDAY ACROSS EASTERN PORTIONS OF THE CWA. THE EURO HAS SHOWN A
COLD BIAS WITH IT/S LAST STORM THAT AFFECTED OUR CWA...SO THE AMOUNT
OF COOLING IS SUSPECT. THE GFS IS SHOWING A BIT MORE OF A SOUTHERLY
TRACK OF THE MEAN TROUGH...AND IS LESS NEGATIVELY TILTED...BUT THE
GFS ENSEMBLE MEAN GIVES SUPPORT TO THE EC SOLUTION. AS STATED
PREVIOUSLY...CONFIDENCE IN ANY PARTICULAR SOLUTION IS LOW...THUS
WILL MAINTAIN 40 PERCENT POPS OR LESS THROUGH THE EVENT AND KEEP THE
GENERAL IDEA OF SHOWERS OF RAIN INITIALLY...THEN POSSIBLY CHANGING
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 630 AM CDT WED APR 3 2013
VFR IS GENERALLY EXPECTED ACROSS ALL AREAS TODAY AND TONIGHT.
LOCAL MVFR/IFR CIGS ARE MOVING NORTH THROUGH THE NEB PANHANDLE
SOUTH OF KAIA. THIS SHOULD MOVE NORTH TO NEAR KAIA THIS MORNING
AND THEN MIX OUT. A NARROW BAND OF MVFR CIGS COULD DEVELOP AOA 06Z TONIGHT
ALONG HIGHWAY 20 AS A COLD FRONT DROPS INTO NRN NEB. OTHERWISE VFR
SHOULD PREVAIL.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
314 AM CDT WED APR 3 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 314 AM CDT WED APR 3 2013
THE RAP...NAM AND GFS ARE SUGGESTING SUFFICIENT LOW AND MID LEVEL
CLOUDINESS ACROSS SRN NEB TO HOLD TEMPS IN THE 50S TODAY. AT THE
SAME TIME SOUTH AND SOUTHWEST WINDS WILL RECIRCULATE COOL AIR NORTH
FROM THE HIGH PRESSURE SYSTEM ACROSS THE MID SOUTH. SO THE RAP 21Z
TEMPS WERE USED AS THE BASIS FOR TODAYS HIGHS WHICH IS CLOSE TO THE
GUIDANCE DATA SETS. IF FULL SUN ARRIVES OR EVEN JUST HIGH LEVEL
CLOUDINESS...HIGHS COULD BE A FEW DEGREES WARMER.
THE BEST GUESS ON TONIGHTS LOWS IS FOR THE CLOUDS TO DEPART WITH
WEAK SFC WINDS DEVELOPING AHEAD OF A COLD FRONT MOVING THROUGH SOUTH
DAKOTA WHICH WOULD SUPPORT SOME RADIATIONAL COOLING ACROSS NEB. LOWS
IN THE UPPER 20S TO MID 30S APPEARS TO BE THE BEST FORECAST.
ADDITIONAL COOLING FROM THE DROUGHT CONDITIONS COULD PUSH LOWS
FURTHER.
THE REST OF THE FCST IS WELL BEHAVED. WINDS COULD REACH THE BREEZY
CATEGORY BUT RELATIVE HUMIDITY WILL RUN 25 TO 30 PERCENT. THE RAP
SUGGESTED LOWER RH ACROSS FAR NORTHWEST NEB AS THE FRONT NOSES SOUTH
LATE THIS AFTN BUT AT THE SAME TIME WINDS WEAKEN.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 314 AM CDT WED APR 3 2013
12Z THURSDAY AND BEYOND. TWO MAIN CONCERNS GOING IN
THE EXTENDED PERIOD. FIRST BEING THE POTENTIAL FOR FIRE HEADLINES
ON FRIDAY...THEREAFTER THE FOCUS TURNS TO THE DEVELOPMENT OF A
WESTERN CONUS TROUGH...WHICH MAY BRING PERIODS OF WIDESPREAD
PRECIPITATION BACK ACROSS THE FORECAST AREA LATE THIS WEEKEND
THROUGH EARLY NEXT WEEK.
SURFACE TEMPERATURES WILL SLOWLY MODERATE FROM WEST TO EAST ON
THURSDAY AS SURFACE HIGH PRESSURE SLOWLY BUILDS EAST ACROSS THE
NORTHERN PLAINS AND ALLOWS FOR A RETURN SOUTHERLY FLOW. A TIGHT
GRADIENT IS EXPECTED IN THE TEMPERATURE FIELD...WITH HIGHS POSSIBLY
APPROACHING 70 ACROSS SOUTHWEST NEBRASKA...BUT READINGS OF ONLY THE
LOW TO MID 50S OVER NORTH CENTRAL NEBRASKA. FOR FRIDAY...THE
NORTHERN PLAINS HIGH WILL BE LOCATED OVER THE GREAT LAKES REGION
WITH STRONG SOUTHERLY RETURN FLOW TARGETING THE ENTIRE FORECAST
AREA. WITH DEEPENING LOW PRESSURE ON THE LEE OF THE ROCKIES...A
TIGHT PRESSURE GRADIENT IS EXPECTED...WITH THE POTENTIAL FOR WIND
GUSTS IN EXCESS OF 25 MPH. MEANWHILE SFC TEMPERATURE AND DEW POINT
SPREADS WILL APPROACH 40 F...WHICH SHOULD LEAD TO LOCALIZED AREAS OF
SUB 20 PERCENT RH. GIVEN THAT GREEN UP HAS NOT YET
OCCURRED...LOCALIZED RED FLAG CONDITIONS ARE POSSIBLE. UNCERTAINTY
REMAINS IF THE RED FLAG CRITERIA WIND GUSTS WILL BE CO-LOCATED
WITHIN THE CRITICAL RH FIELD. AT THIS TIME...IT APPEARS THAT THE
STRONGEST GUSTS SHOULD OCCUR OVER EASTERN PORTIONS OF THE
CWA...WHERE THE SOUTHERLY FLOW SHOULD HELP PUSH TD/S UP NEAR
40...WHICH WOULD KEEP MINIMUM RH IN THE 20-30 PERCENT RANGE. THE
DRIEST AIR IS EXPECTED ACROSS THE WESTERN HALF OF THE CWA...SLIGHTLY
REMOVED FROM THE STRONGEST GUSTS. OBVIOUSLY THERE IS STILL TIME TO
HAMMER OUT THE DETAILS...BUT GIVEN A FAVORABLE FIRE WX PATTERN
/RIDGE BREAKDOWN/ AND THE FACT THAT WIND SHIFT IS EXPECTED LATE
AFTERNOON/EVENING AS A SURFACE TROUGH AND COLD FRONT ADVANCE EAST
ACROSS THE CWA...ITS SAFE TO SAY AT THIS JUNCTURE THAT ELEVATED FIRE
CONCERNS ARE CERTAINLY WARRANTED...WILL CONTINUE TO MONITOR. ALSO
OF CONCERN...PROXIMITY SOUNDINGS INDICATE WEAK INSTABILITY ALONG THE
FRONTAL PASSAGE...BUT DRY LOWER LEVELS...A FEW DRIER CG STRIKES COULD
OCCUR. OTHERWISE HIGH TEMPERATURES WILL COOL SOME TEN DEGREES FROM
THE MID 70S DOWN TO THE UPPER 50S TO MID 60S ON SATURDAY. LOWS
FRIDAY AND SATURDAY MORNING WILL BE MILD RELATIVELY SPEAKING...WITH
LOWS IN THE 30S FRIDAY...AND LOWS IN THE 40S SATURDAY MORNING.
ATTENTION NOW TURNS TO THE MYRIAD OF POTENTIAL WEATHER FOR LATE
SUNDAY THROUGH EARLY NEXT WEEK...BUT UNFORTUNATELY THE 03.00Z RUN OF
THE MODELS FAILED TO INCREASE FORECAST CONFIDENCE AS SIGNIFICANT
DIFFERENCES IN TIMING AND STRENGTH OF THE WESTERN CONUS TROUGH
EXISTS. THE GENERAL IDEA IS THAT A SHORTWAVE WILL CROSS THE
CENTRAL/NORTHERN PLAINS ON SUNDAY PROVIDING FOR SHOWERS AND/OR
TSTMS...THEN THE MEAN TROUGH WILL DEVELOP OVER THE ROCKIES AND
SLOWLY ADVANCE OUT ONTO THE PLAINS EARLY NEXT WEEK. THE EC SOLUTION
CONTINUES TO ADVERTISE ENOUGH COLD AIR ON THE BACK SIDE OF THE MAIN
H5 LOW TO ALLOW FOR SNOW ACCUMULATIONS...WHICH MAY BE SIGNIFICANT.
ALSO OF NOTE...THE EC DEVELOPS H85 WINDS IN EXCESS OF 60KTS EARLY
TUESDAY ACROSS EASTERN PORTIONS OF THE CWA. THE EURO HAS SHOWN A
COLD BIAS WITH IT/S LAST STORM THAT AFFECTED OUR CWA...SO THE AMOUNT
OF COOLING IS SUSPECT. THE GFS IS SHOWING A BIT MORE OF A SOUTHERLY
TRACK OF THE MEAN TROUGH...AND IS LESS NEGATIVELY TILTED...BUT THE
GFS ENSEMBLE MEAN GIVES SUPPORT TO THE EC SOLUTION. AS STATED
PREVIOUSLY...CONFIDENCE IN ANY PARTICULAR SOLUTION IS LOW...THUS
WILL MAINTAIN 40 PERCENT POPS OR LESS THROUGH THE EVENT AND KEEP THE
GENERAL IDEA OF SHOWERS OF RAIN INITIALLY...THEN POSSIBLY CHANGING
OVER TO SNOW MONDAY NIGHT INTO TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1240 AM CDT WED APR 3 2013
SATELLITE IMAGERY IS SHOWING LOW CLOUDS WITH CEILINGS 1000-2000 FEET
AGL ACROSS EASTERN COLORADO AND 2000-3000 FEET IN NORTHWEST KANSAS
AND EXTREME SOUTHWEST NEBRASKA. A PROJECTION OF THE CURRENT MOVEMENT
KEEPS THE LOWER CLOUDS SOUTH OF AN OGA-LBF LINE. HOWEVER...LOW LEVEL
WIND WOULD INDICATE SOME PROGRESS FARTHER NORTH THAN THAT. IN
FACT...SHORT RANGE PROJECTIONS FROM THE EVENING MODEL RUN SHOW THE
LOWER CLOUDS SPREADING THROUGH OGA TO MHN BUT STILL WEST OF LBF AND
SOUTHWEST OF VTN. SO...FOR NOW...WE WILL KEEP LOW CEILINGS OUT OF
THE FORECASTS FOR LBF AND VTN.
WIND WILL BE BELOW 10KT UNTIL LATE MORNING...AROUND 15Z...WHEN IT
WILL INCREASE AGAIN AND BECOME 190-220 AT 16-20G24-28KT IN THE NORTH
AND 180-210 AT 12-14G18-24KT IN THE SOUTHWEST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1227 PM CDT WED APR 3 2013
.UPDATE...
SEE UPDATED AVIATION DISCUSSION BELOW.
LATE MORNING UPDATE TODAY INCLUDED INCREASING WIND SPEEDS AND
ENHANCING A CORRIDOR OF STRONGER WINDS ALONG AND JUST EAST OF THE
EASTERN SLOPE OF THE PRAIRIE COTEAU. LEFT EVERYTHING ELSE AS IS
SINCE THERMAL ADVECTION SUGGESTS WE SHOULD GET CLOSE TO ADVERTISED
HIGH TEMPS TODAY...AND LATEST HRRR AND 12Z SPC WRF CONTINUES TO
HINT AT ISOLATED TO WIDELY SCATTERED WEAK CONVECTION THIS
AFTERNOON THROUGH EARLY THIS EVENING.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH FRIDAY
MAIN CONCERNS THROUGH THE PERIOD ARE TEMPERATURES AND PCPN CHANCES.
FOR TODAY THE REGION SHOULD BASK IN A RELATIVELY MILD AIRMASS AS
SOUTHWEST BREEZES KICK IN AHEAD OF AN ADVANCING FRONT. MODEL H85
TEMPS ARE EXPECTED TO RANGE FROM 5 TO 10 DEGREES C WHICH SUGGESTS
THE SOUTHWEST CWA SHOULD GET CLOSE TO 70 PROVIDED MIXING IS
SUFFICIENT. THE NORTHEAST CWA REMAINS PROBLEMATIC AS SNOW IS STILL
COVERING A MAJOR PORTION OF THE GLACIAL LAKES AREA. FOR NOW AM
GOING CLOSE TO A MODEL BLEND FOR THAT REGION. MEANWHILE THE MODELS
CONTINUE TO CRANK OUT SOME LIGHT PCPN JUST BEHIND THE FRONT LATE
TODAY AND TNT AS IT CROSSES THE CWA. TIME HEIGHTS AND SOUNDINGS
INDICATE SOME LOWER LEVEL DRY AIR THAT WOULD HAVE TO BE OVERCOME
FOR MUCH IN THE WAY OF MEASURABLE PCPN. SO...SLIGHT CHANCE POPS
LOOK FINE. IT SHOULD THEN BE MAINLY DRY FOR THURSDAY THROUGH
FRIDAY BEFORE THE NEXT SYSTEM MOVES IN LATER ON FRIDAY. THAT
SYSTEM SHOULD BRING SOME WAA PCPN TO THE NORTHERN PARTS OF THE
STATE FRIDAY INTO FRIDAY NIGHT. FOR NOW IT APPEARS TO BE MOSTLY
RAIN GIVEN EXPECTED TEMPERATURES AND PROGGED PARTIAL THICKNESS.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
FAIRLY ACTIVE PATTERN LOOKS TO BE SETTING UP ACROSS THE NORTHERN
PLAINS WITH THE FIRST WAVE OF INTEREST MOVING THROUGH THE AREA
FRIDAY NIGHT AND SATURDAY. MODELS IN GENERAL AGREEMENT IN MOVING
THE SFC LOW EASTWARD ACROSS SOUTHERN SOUTH DAKOTA. CONFIDENCE IS
INCREASING IN THERE BEING PRECIP NORTH OF THE WARM FRONT ACROSS
THE NORTHEASTERN CWA. HAVE INCREASED POPS A BIT. AS THE SFC LOW
MOVES INTO MN BY SATURDAY...COLDER AIR WRAPS INTO THE
CWA...ALTHOUGH MODELS ARE STILL VARYING QUITE A BIT IN THEIR
THERMAL PROFILES ON THE BACK SIDE OF THIS SYSTEM. EC IS RATHER
WARM WHILE GFS IS COOLER. FOR RIGHT NOW HAVE JUST ALL RAIN IN THE
FORECAST BUT IF MODELS TURN A BIT COLDER...COULD ALSO SEE SOME
SNOW MIXED IN AS WELL BY SATURDAY MORNING. IT LOOKS LIKE ANOTHER
DECENT LOOKING WAVE MOVES THROUGH ON SUNDAY...WITH FAIR AGREEMENT
AMONGST THE MODELS. GENERALLY ACCEPTED ALLBLEND POP GRIDS FOR THIS
SYSTEM. HEADING INTO EARLY NEXT WEEK THINGS BECOME MUCH MORE
UNCERTAIN. ALLBLEND POPS MAY BE OVERDONE INTO EARLY NEXT WEEK AS
MODELS ARE SHOWING SFC HIGH RIDGING ACROSS THE AREA...BUT ALLBLEND
GIVING POPS. MAY NEED TO BACK OFF MORE ON THIS. MODELS HAVE
TRENDED A BIT FURTHER SOUTH WITH ANOTHER POTENTIAL STORM SYSTEM
EARLY NEXT WEEK.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF FORECAST PERIOD.
BREEZY SOUTHERLY SFC WINDS WILL CONTINUE ACROSS THE REGION THIS AFTERNOON.
A COLD FRONT WILL SWEEP SOUTHEAST ACROSS THE AREA THIS AFTERNOON
AND EVENING...SWITCHING SFC WINDS TO A NORTHERLY DIRECTION. SOME
LIGHT SHOWERS ARE POSSIBLE AHEAD OF THIS FRONT. CURRENTLY A LINE
STRETCHES FROM BISMARCK TO LEMMON PROGRESSING SOUTHEASTWARD. NO
IMPACTS ARE EXPECTED TO TAFS WITH THESE SHOWERS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...WISE
SHORT TERM...TDK
LONG TERM...TMT
AVIATION...WISE
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1222 PM CDT WED APR 3 2013
.UPDATE...
LATE MORNING UPDATE TODAY INCLUDED INCREASING WIND SPEEDS AND
ENHANCING A CORRIDOR OF STRONGER WINDS ALONG AND JUST EAST OF THE
EASTERN SLOPE OF THE PRAIRIE COTEAU. LEFT EVERYTHING ELSE AS IS
SINCE THERMAL ADVECTION SUGGESTS WE SHOULD GET CLOSE TO ADVERTISED
HIGH TEMPS TODAY...AND LATEST HRRR AND 12Z SPC WRF CONTINUES TO
HINT AT ISOLATED TO WIDELY SCATTERED WEAK CONVECTION THIS
AFTERNOON THROUGH EARLY THIS EVENING.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH FRIDAY
MAIN CONCERNS THROUGH THE PERIOD ARE TEMPERATURES AND PCPN CHANCES.
FOR TODAY THE REGION SHOULD BASK IN A RELATIVELY MILD AIRMASS AS
SOUTHWEST BREEZES KICK IN AHEAD OF AN ADVANCING FRONT. MODEL H85
TEMPS ARE EXPECTED TO RANGE FROM 5 TO 10 DEGREES C WHICH SUGGESTS
THE SOUTHWEST CWA SHOULD GET CLOSE TO 70 PROVIDED MIXING IS
SUFFICIENT. THE NORTHEAST CWA REMAINS PROBLEMATIC AS SNOW IS STILL
COVERING A MAJOR PORTION OF THE GLACIAL LAKES AREA. FOR NOW AM
GOING CLOSE TO A MODEL BLEND FOR THAT REGION. MEANWHILE THE MODELS
CONTINUE TO CRANK OUT SOME LIGHT PCPN JUST BEHIND THE FRONT LATE
TODAY AND TNT AS IT CROSSES THE CWA. TIME HEIGHTS AND SOUNDINGS
INDICATE SOME LOWER LEVEL DRY AIR THAT WOULD HAVE TO BE OVERCOME
FOR MUCH IN THE WAY OF MEASURABLE PCPN. SO...SLIGHT CHANCE POPS
LOOK FINE. IT SHOULD THEN BE MAINLY DRY FOR THURSDAY THROUGH
FRIDAY BEFORE THE NEXT SYSTEM MOVES IN LATER ON FRIDAY. THAT
SYSTEM SHOULD BRING SOME WAA PCPN TO THE NORTHERN PARTS OF THE
STATE FRIDAY INTO FRIDAY NIGHT. FOR NOW IT APPEARS TO BE MOSTLY
RAIN GIVEN EXPECTED TEMPERATURES AND PROGGED PARTIAL THICKNESS.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
FAIRLY ACTIVE PATTERN LOOKS TO BE SETTING UP ACROSS THE NORTHERN
PLAINS WITH THE FIRST WAVE OF INTEREST MOVING THROUGH THE AREA
FRIDAY NIGHT AND SATURDAY. MODELS IN GENERAL AGREEMENT IN MOVING
THE SFC LOW EASTWARD ACROSS SOUTHERN SOUTH DAKOTA. CONFIDENCE IS
INCREASING IN THERE BEING PRECIP NORTH OF THE WARM FRONT ACROSS
THE NORTHEASTERN CWA. HAVE INCREASED POPS A BIT. AS THE SFC LOW
MOVES INTO MN BY SATURDAY...COLDER AIR WRAPS INTO THE
CWA...ALTHOUGH MODELS ARE STILL VARYING QUITE A BIT IN THEIR
THERMAL PROFILES ON THE BACK SIDE OF THIS SYSTEM. EC IS RATHER
WARM WHILE GFS IS COOLER. FOR RIGHT NOW HAVE JUST ALL RAIN IN THE
FORECAST BUT IF MODELS TURN A BIT COLDER...COULD ALSO SEE SOME
SNOW MIXED IN AS WELL BY SATURDAY MORNING. IT LOOKS LIKE ANOTHER
DECENT LOOKING WAVE MOVES THROUGH ON SUNDAY...WITH FAIR AGREEMENT
AMONGST THE MODELS. GENERALLY ACCEPTED ALLBLEND POP GRIDS FOR THIS
SYSTEM. HEADING INTO EARLY NEXT WEEK THINGS BECOME MUCH MORE
UNCERTAIN. ALLBLEND POPS MAY BE OVERDONE INTO EARLY NEXT WEEK AS
MODELS ARE SHOWING SFC HIGH RIDGING ACROSS THE AREA...BUT ALLBLEND
GIVING POPS. MAY NEED TO BACK OFF MORE ON THIS. MODELS HAVE
TRENDED A BIT FURTHER SOUTH WITH ANOTHER POTENTIAL STORM SYSTEM
EARLY NEXT WEEK.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF FORECAST PERIOD.
BREEZY SOUTHERLY SFC WINDS WILL DEVELOP ACROSS THE REGION TODAY. A
COLD FRONT WILL THEN SWEEP SOUTHEAST ACROSS THE AREA THIS
EVENING...SWITCHING SFC WINDS TO A NORTHERLY DIRECTION.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...DORN
SHORT TERM...TDK
LONG TERM...TMT
AVIATION...TMT
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1244 PM CDT WED APR 3 2013
.AVIATION...
CONDITIONS AT KLBB ARE EXPECTED TO IMPROVE THIS AFTERNOON AS DRY
SLOT ROTATING ACROSS THE UPPER LEVEL LOW TO OUR NORTHWEST HELPS TO
DRY LOW LEVEL CONDITIONS. CLOUDS ARE EXPECTED TO HANG AROUND KCDS
THOUGH SOME UNCERTAINTY EXISTS IN THE FLIGHT CATEGORY AS IFR
CONDITIONS PERSIST JUST NORTH OF THAT TERMINAL. INTO THE OVERNIGHT
HOURS...CLEARING SKIES AND LIGHT WINDS WILL LIKELY HELP FOG
FORMATION. HAVE GONE FAIRLY CONSERVATIVELY ON VISIBILITY FOR NOW
THOUGH VLIFR IS POSSIBLE.
&&
.PREV DISCUSSION... /ISSUED 634 AM CDT WED APR 3 2013/
AVIATION...
IFR CONDITIONS LIKELY TO PERSIST INTO THE AFTN HOURS AT BOTH TAF
SITES. KLBB MAY SEE SOME LIFTING OF THE CIGS THIS AFTN THEN
PROBABLY SCATTER OUT THIS EVENING. KCDS LOOKS LESS LIKELY TO SEE
MUCH IMPROVEMENT UNTIL LATE IN THE TAF PERIOD OR BEYOND.
DEEP MOISTURE NOT AS RICH AS EXPECTED WHICH WILL RESULT IN GREATLY
REDUCED PRECIP CHANCES TODAY. BOTH TAF SITES...KCDS MORESO THAN
KLBB...COULD SEE SOME LIGHT SHOWERS BUT CHANCES NOW LOOK TO SLIM
TO MENTION GIVEN RESTRICTIONS ON PROB30 GROUP WITHIN FIRST 9
HOURS OF TAF PERIOD.
PREV DISCUSSION... /ISSUED 410 AM CDT WED APR 3 2013/
SHORT TERM...
MAJOR CHANGE TO THE FCST THIS MORNING IS TO CONSIDERABLY LOWER POPS
ACROSS THE AREA. UNFORTUNATELY...PREVIOUS MODEL RUNS MISSED THE
EXTENSIVE MCS THAT MOVED ACROSS AREAS FROM NW TEXAS TO SOUTH TEXAS.
IT APPEARS THAT THIS MCS WILL LEAVE THE FCST AREA STARVED OF DEEP
MOISTURE AND THUS THE LIFT ASSOCIATED WITH THE LOW OVER CNTL
COLORADO WILL LIKELY PRODUCE MUCH LESS PRECIP THAN PREVIOUSLY
EXPECTED. THE 00Z MODEL SUITE MISSED THIS CRITICAL ELEMENT RESULTING
IN TOO MUCH WIDESPREAD QPF AND MOS GUIDANCE WHOSE POPS APPEAR TO BE
TOO HIGH. HAVE TRENDED THE FCST MUCH CLOSER TO THE 06Z RUC WHICH DID
INITIALIZE THE MCS AND SUBSEQUENTLY SEEMS TO HAVE A BETTER HANDLE ON
POSSIBLE PRECIP TODAY. THAT POSSIBILITY THEN SEEMS TO FOCUS ON
POTENTIAL FOR SCATTERED LIGHT SHOWERS MAINLY ACROSS THE NRN ZONES IN
AN AREA OF LIFT JUST AHEAD AND SOUTH OF THE TRACK OF THE UPPER LOW.
PRECIP HAS BEEN HARD TO COME BY VCNTY OF THE LOW WITH SOME LIGHT RA
AND SN IN SRN COLORADO AND SOME LIGHT RA SOUTH OF KABQ IN CNTL NM AS
A JET STREAK ROTATES AROUND THE BASE OF THE TROUGH.
IN THE NEAR TERM EVEN DRIZZLE CHANCES APPEAR TO BE ON THE WANE AS A
MID LEVEL DRY SLOT AND SOME APPARENT DOWNWARD MOTION TO THE REAR OF
THE CNTL TX MCS WORK IN ACROSS THE AREA. COULD SEE DRIZZLE TRY TO
REDEVELOP A LITTLE LATER THIS MORNING ONCE SOME WEAK LIFT WORKS BACK
OVER THE AREA...BUT EVEN MEASURABLE PRECIP FROM THIS ELEMENT LOOKING
VERY UNLIKELY.
TEMP FCST WILL BE TRICKY FOR THIS AFTN WITH SOME UNCERTAINTY
REGARDING HOW MUCH LOW STRATUS WILL REMAIN IN PLACE OR THIN. 00Z
MODELS APPEAR TO BE TOO AGGRESSIVE WITH WARMING AND HAVE TRENDED
TEMPS A BIT BELOW MOS. HOWEVER...ANY LATE DAY CLEARING OR LIFTING OF
CEILINGS AS THE CENTER OF THE LOW MOVES ACROSS THE SRN PANHANDLE
WOULD SEE TEMPS APPROACH THAT PROGGED BY MOS. THIS WOULD BE MOST
LIKELY TO OCCUR ACROSS THE SWRN ZONES.
MOVING INTO TONIGHT...LESSENING RAIN CHANCES SHOULD SHIFT EAST OF
THE AREA BY EARLY EVENING. MODELS KEEP LOW LEVEL MOISTURE LEVELS
PRETTY STEADY WHILE DROPPING WINDS OFF TO BECOME VERY LIGHT. SOME
HINTING OF FOG POTENTIAL LATE TONIGHT...AND IF MORE RAIN HAD FALLEN
IN THE LAST 24 HOURS OR MORE FALLS THAN EXPECTED OVER THE NEXT
SEVERAL HOURS WOULD BE MORE INCLINED TO MENTION AREAS OF FOG IN THE
FCST. STILL A BIT TOO MUCH UNCERTAINTY HERE AND WILL LET NEXT SHIFT
REEVALUATE THAT POTENTIAL.
LONG TERM...
A RETURN TO MORE SEASONABLE TEMPS REMAINS ON TRACK BEGINNING
TOMORROW AS THE SOUTH PLAINS SHAKES THE RECENT FORAY OF MODIFIED
CANADIAN AIR. A BEVERAGE SUCH AS CANADA DRY WOULD PROVE FITTING
FOR THE NEXT SEVERAL DAYS AS TRANSIENT RIDGING ALOFT CARRIES A
DOME OF VERY MILD AND DRY AIR EAST OVER MUCH OF THE SOUTH PLAINS.
BY FRIDAY...WE SHOULD SEE A PALTRY DRYLINE EVOLVE IN THE ROLLING
PLAINS BEHIND THE DEPARTING SURFACE HIGH. QUALITY RETURN FLOW
HOWEVER IS NOT EXPECTED UNTIL SATURDAY AT WHICH POINT STRONGER
WESTERLY WINDS ALOFT BEHIND THE UPPER RIDGE WILL SHUNT MUCH OF
THIS SHALLOW MOISTURE OUT OF ALL BUT OUR FAR EASTERN COLUMN OF
COUNTIES. A MINOR SHORT WAVE TROUGH IS STILL PROGGED TO SLIDE
THROUGH THIS STRONGER WESTERLY FLOW BY SAT NIGHT/SUN MORNING
ACCOMPANIED BY PERHAPS EVEN DRIER AND WARMER CONDITIONS ON
SUNDAY...BUT WILL STICK WITH SLIGHTLY COOLER CONDITIONS AS A
COLD FRONT WILL BE FOUND EDGING PERILOUSLY CLOSE TO OUR NRN
COUNTIES IN THE WAKE OF THIS UPPER IMPULSE.
BY EARLY NEXT WEEK...NO CHANGES ARE WARRANTED ATTM AS MODELS ARE
NOW IN MORE DISAGREEMENT THAN 24 HOURS AGO. WPC CONTINUES TO FAVOR
A SLOWER AND DEEPER LONGWAVE TROUGH EVOLVING IN THE GREAT BASIN
AND FOUR CORNERS REGION BY THIS TIME. ONLY SIMILARITY AMONG THE
CURRENT ECMWF AND GFS IS THAT THIS WAVE WOULD BE OPEN AND
PROGRESSIVE...THOUGH SIGNIFICANT DIFFERENCES EMERGE IN THE TIMING
OF SAID WAVE AND HOW MUCH CP AIR IS DRAWN SOUTHWARD FOLLOWING ITS
PASSAGE. WOULD STILL EXPECT A SEMI-ACTIVE DRYLINE TO UNFOLD NEAR
THE FRINGES OF OUR EASTERN COUNTIES AS EARLY AS MON AND PERHAPS
LINGERING INTO TUE UNDERNEATH AN INCREASINGLY UNSETTLED SWLY UPPER
FLOW REGIME. THE GEFS MEAN AND EVEN THE CMC INDICATE SUCH A
SCENARIO THAT AS OF YESTERDAY WAS FAVORED BY THE ECMWF...BUT WILL
AWAIT LATER MODEL RUNS BEFORE COMMITTING TO ANY CHANGES STILL SO
MANY PERIODS OUT.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 46 32 68 43 76 / 40 10 0 0 0
TULIA 41 32 67 43 77 / 40 10 0 0 0
PLAINVIEW 41 34 68 44 77 / 30 10 0 0 0
LEVELLAND 48 34 70 46 81 / 30 10 0 0 0
LUBBOCK 43 35 70 45 79 / 30 10 0 0 0
DENVER CITY 51 34 70 47 82 / 20 10 0 0 0
BROWNFIELD 48 35 70 46 82 / 30 10 0 0 0
CHILDRESS 43 35 64 43 78 / 40 20 0 0 0
SPUR 41 35 68 45 81 / 30 10 0 0 0
ASPERMONT 43 37 66 44 80 / 30 10 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99/26
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
634 AM CDT WED APR 3 2013
.AVIATION...
IFR CONDITIONS LIKELY TO PERSIST INTO THE AFTN HOURS AT BOTH TAF
SITES. KLBB MAY SEE SOME LIFTING OF THE CIGS THIS AFTN THEN
PROBABLY SCATTER OUT THIS EVENING. KCDS LOOKS LESS LIKELY TO SEE
MUCH IMPROVEMENT UNTIL LATE IN THE TAF PERIOD OR BEYOND.
DEEP MOISTURE NOT AS RICH AS EXPECTED WHICH WILL RESULT IN GREATLY
REDUCED PRECIP CHANCES TODAY. BOTH TAF SITES...KCDS MORESO THAN
KLBB...COULD SEE SOME LIGHT SHOWERS BUT CHANCES NOW LOOK TO SLIM
TO MENTION GIVEN RESTRICTIONS ON PROB30 GROUP WITHIN FIRST 9
HOURS OF TAF PERIOD.
&&
.PREV DISCUSSION... /ISSUED 410 AM CDT WED APR 3 2013/
SHORT TERM...
MAJOR CHANGE TO THE FCST THIS MORNING IS TO CONSIDERABLY LOWER POPS
ACROSS THE AREA. UNFORTUNATELY...PREVIOUS MODEL RUNS MISSED THE
EXTENSIVE MCS THAT MOVED ACROSS AREAS FROM NW TEXAS TO SOUTH TEXAS.
IT APPEARS THAT THIS MCS WILL LEAVE THE FCST AREA STARVED OF DEEP
MOISTURE AND THUS THE LIFT ASSOCIATED WITH THE LOW OVER CNTL
COLORADO WILL LIKELY PRODUCE MUCH LESS PRECIP THAN PREVIOUSLY
EXPECTED. THE 00Z MODEL SUITE MISSED THIS CRITICAL ELEMENT RESULTING
IN TOO MUCH WIDESPREAD QPF AND MOS GUIDANCE WHOSE POPS APPEAR TO BE
TOO HIGH. HAVE TRENDED THE FCST MUCH CLOSER TO THE 06Z RUC WHICH DID
INITIALIZE THE MCS AND SUBSEQUENTLY SEEMS TO HAVE A BETTER HANDLE ON
POSSIBLE PRECIP TODAY. THAT POSSIBILITY THEN SEEMS TO FOCUS ON
POTENTIAL FOR SCATTERED LIGHT SHOWERS MAINLY ACROSS THE NRN ZONES IN
AN AREA OF LIFT JUST AHEAD AND SOUTH OF THE TRACK OF THE UPPER LOW.
PRECIP HAS BEEN HARD TO COME BY VCNTY OF THE LOW WITH SOME LIGHT RA
AND SN IN SRN COLORADO AND SOME LIGHT RA SOUTH OF KABQ IN CNTL NM AS
A JET STREAK ROTATES AROUND THE BASE OF THE TROUGH.
IN THE NEAR TERM EVEN DRIZZLE CHANCES APPEAR TO BE ON THE WANE AS A
MID LEVEL DRY SLOT AND SOME APPARENT DOWNWARD MOTION TO THE REAR OF
THE CNTL TX MCS WORK IN ACROSS THE AREA. COULD SEE DRIZZLE TRY TO
REDEVELOP A LITTLE LATER THIS MORNING ONCE SOME WEAK LIFT WORKS BACK
OVER THE AREA...BUT EVEN MEASURABLE PRECIP FROM THIS ELEMENT LOOKING
VERY UNLIKELY.
TEMP FCST WILL BE TRICKY FOR THIS AFTN WITH SOME UNCERTAINTY
REGARDING HOW MUCH LOW STRATUS WILL REMAIN IN PLACE OR THIN. 00Z
MODELS APPEAR TO BE TOO AGGRESSIVE WITH WARMING AND HAVE TRENDED
TEMPS A BIT BELOW MOS. HOWEVER...ANY LATE DAY CLEARING OR LIFTING OF
CEILINGS AS THE CENTER OF THE LOW MOVES ACROSS THE SRN PANHANDLE
WOULD SEE TEMPS APPROACH THAT PROGGED BY MOS. THIS WOULD BE MOST
LIKELY TO OCCUR ACROSS THE SWRN ZONES.
MOVING INTO TONIGHT...LESSENING RAIN CHANCES SHOULD SHIFT EAST OF
THE AREA BY EARLY EVENING. MODELS KEEP LOW LEVEL MOISTURE LEVELS
PRETTY STEADY WHILE DROPPING WINDS OFF TO BECOME VERY LIGHT. SOME
HINTING OF FOG POTENTIAL LATE TONIGHT...AND IF MORE RAIN HAD FALLEN
IN THE LAST 24 HOURS OR MORE FALLS THAN EXPECTED OVER THE NEXT
SEVERAL HOURS WOULD BE MORE INCLINED TO MENTION AREAS OF FOG IN THE
FCST. STILL A BIT TOO MUCH UNCERTAINTY HERE AND WILL LET NEXT SHIFT
REEVALUATE THAT POTENTIAL.
LONG TERM...
A RETURN TO MORE SEASONABLE TEMPS REMAINS ON TRACK BEGINNING
TOMORROW AS THE SOUTH PLAINS SHAKES THE RECENT FORAY OF MODIFIED
CANADIAN AIR. A BEVERAGE SUCH AS CANADA DRY WOULD PROVE FITTING
FOR THE NEXT SEVERAL DAYS AS TRANSIENT RIDGING ALOFT CARRIES A
DOME OF VERY MILD AND DRY AIR EAST OVER MUCH OF THE SOUTH PLAINS.
BY FRIDAY...WE SHOULD SEE A PALTRY DRYLINE EVOLVE IN THE ROLLING
PLAINS BEHIND THE DEPARTING SURFACE HIGH. QUALITY RETURN FLOW
HOWEVER IS NOT EXPECTED UNTIL SATURDAY AT WHICH POINT STRONGER
WESTERLY WINDS ALOFT BEHIND THE UPPER RIDGE WILL SHUNT MUCH OF
THIS SHALLOW MOISTURE OUT OF ALL BUT OUR FAR EASTERN COLUMN OF
COUNTIES. A MINOR SHORT WAVE TROUGH IS STILL PROGGED TO SLIDE
THROUGH THIS STRONGER WESTERLY FLOW BY SAT NIGHT/SUN MORNING
ACCOMPANIED BY PERHAPS EVEN DRIER AND WARMER CONDITIONS ON
SUNDAY...BUT WILL STICK WITH SLIGHTLY COOLER CONDITIONS AS A
COLD FRONT WILL BE FOUND EDGING PERILOUSLY CLOSE TO OUR NRN
COUNTIES IN THE WAKE OF THIS UPPER IMPULSE.
BY EARLY NEXT WEEK...NO CHANGES ARE WARRANTED ATTM AS MODELS ARE
NOW IN MORE DISAGREEMENT THAN 24 HOURS AGO. WPC CONTINUES TO FAVOR
A SLOWER AND DEEPER LONGWAVE TROUGH EVOLVING IN THE GREAT BASIN
AND FOUR CORNERS REGION BY THIS TIME. ONLY SIMILARITY AMONG THE
CURRENT ECMWF AND GFS IS THAT THIS WAVE WOULD BE OPEN AND
PROGRESSIVE...THOUGH SIGNIFICANT DIFFERENCES EMERGE IN THE TIMING
OF SAID WAVE AND HOW MUCH CP AIR IS DRAWN SOUTHWARD FOLLOWING ITS
PASSAGE. WOULD STILL EXPECT A SEMI-ACTIVE DRYLINE TO UNFOLD NEAR
THE FRINGES OF OUR EASTERN COUNTIES AS EARLY AS MON AND PERHAPS
LINGERING INTO TUE UNDERNEATH AN INCREASINGLY UNSETTLED SWLY UPPER
FLOW REGIME. THE GEFS MEAN AND EVEN THE CMC INDICATE SUCH A
SCENARIO THAT AS OF YESTERDAY WAS FAVORED BY THE ECMWF...BUT WILL
AWAIT LATER MODEL RUNS BEFORE COMMITTING TO ANY CHANGES STILL SO
MANY PERIODS OUT.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 46 32 68 43 76 / 40 10 0 0 0
TULIA 41 32 67 43 77 / 40 10 0 0 0
PLAINVIEW 41 34 68 44 77 / 30 10 0 0 0
LEVELLAND 48 34 70 46 81 / 30 10 0 0 0
LUBBOCK 43 35 70 45 79 / 30 10 0 0 0
DENVER CITY 51 34 70 47 82 / 20 10 0 0 0
BROWNFIELD 48 35 70 46 82 / 30 10 0 0 0
CHILDRESS 43 35 64 43 78 / 40 20 0 0 0
SPUR 41 35 68 45 81 / 30 10 0 0 0
ASPERMONT 43 37 66 44 80 / 30 10 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07/93/07
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
410 AM CDT WED APR 3 2013
.SHORT TERM...
MAJOR CHANGE TO THE FCST THIS MORNING IS TO CONSIDERABLY LOWER POPS
ACROSS THE AREA. UNFORTUNATELY...PREVIOUS MODEL RUNS MISSED THE
EXTENSIVE MCS THAT MOVED ACROSS AREAS FROM NW TEXAS TO SOUTH TEXAS.
IT APPEARS THAT THIS MCS WILL LEAVE THE FCST AREA STARVED OF DEEP
MOISTURE AND THUS THE LIFT ASSOCIATED WITH THE LOW OVER CNTL
COLORADO WILL LIKELY PRODUCE MUCH LESS PRECIP THAN PREVIOUSLY
EXPECTED. THE 00Z MODEL SUITE MISSED THIS CRITICAL ELEMENT RESULTING
IN TOO MUCH WIDESPREAD QPF AND MOS GUIDANCE WHOSE POPS APPEAR TO BE
TOO HIGH. HAVE TRENDED THE FCST MUCH CLOSER TO THE 06Z RUC WHICH DID
INITIALIZE THE MCS AND SUBSEQUENTLY SEEMS TO HAVE A BETTER HANDLE ON
POSSIBLE PRECIP TODAY. THAT POSSIBILITY THEN SEEMS TO FOCUS ON
POTENTIAL FOR SCATTERED LIGHT SHOWERS MAINLY ACROSS THE NRN ZONES IN
AN AREA OF LIFT JUST AHEAD AND SOUTH OF THE TRACK OF THE UPPER LOW.
PRECIP HAS BEEN HARD TO COME BY VCNTY OF THE LOW WITH SOME LIGHT RA
AND SN IN SRN COLORADO AND SOME LIGHT RA SOUTH OF KABQ IN CNTL NM AS
A JET STREAK ROTATES AROUND THE BASE OF THE TROUGH.
IN THE NEAR TERM EVEN DRIZZLE CHANCES APPEAR TO BE ON THE WANE AS A
MID LEVEL DRY SLOT AND SOME APPARENT DOWNWARD MOTION TO THE REAR OF
THE CNTL TX MCS WORK IN ACROSS THE AREA. COULD SEE DRIZZLE TRY TO
REDEVELOP A LITTLE LATER THIS MORNING ONCE SOME WEAK LIFT WORKS BACK
OVER THE AREA...BUT EVEN MEASURABLE PRECIP FROM THIS ELEMENT LOOKING
VERY UNLIKELY.
TEMP FCST WILL BE TRICKY FOR THIS AFTN WITH SOME UNCERTAINTY
REGARDING HOW MUCH LOW STRATUS WILL REMAIN IN PLACE OR THIN. 00Z
MODELS APPEAR TO BE TOO AGGRESSIVE WITH WARMING AND HAVE TRENDED
TEMPS A BIT BELOW MOS. HOWEVER...ANY LATE DAY CLEARING OR LIFTING OF
CEILINGS AS THE CENTER OF THE LOW MOVES ACROSS THE SRN PANHANDLE
WOULD SEE TEMPS APPROACH THAT PROGGED BY MOS. THIS WOULD BE MOST
LIKELY TO OCCUR ACROSS THE SWRN ZONES.
MOVING INTO TONIGHT...LESSENING RAIN CHANCES SHOULD SHIFT EAST OF
THE AREA BY EARLY EVENING. MODELS KEEP LOW LEVEL MOISTURE LEVELS
PRETTY STEADY WHILE DROPPING WINDS OFF TO BECOME VERY LIGHT. SOME
HINTING OF FOG POTENTIAL LATE TONIGHT...AND IF MORE RAIN HAD FALLEN
IN THE LAST 24 HOURS OR MORE FALLS THAN EXPECTED OVER THE NEXT
SEVERAL HOURS WOULD BE MORE INCLINED TO MENTION AREAS OF FOG IN THE
FCST. STILL A BIT TOO MUCH UNCERTAINTY HERE AND WILL LET NEXT SHIFT
REEVALUATE THAT POTENTIAL.
&&
.LONG TERM...
A RETURN TO MORE SEASONABLE TEMPS REMAINS ON TRACK BEGINNING
TOMORROW AS THE SOUTH PLAINS SHAKES THE RECENT FORAY OF MODIFIED
CANADIAN AIR. A BEVERAGE SUCH AS CANADA DRY WOULD PROVE FITTING
FOR THE NEXT SEVERAL DAYS AS TRANSIENT RIDGING ALOFT CARRIES A
DOME OF VERY MILD AND DRY AIR EAST OVER MUCH OF THE SOUTH PLAINS.
BY FRIDAY...WE SHOULD SEE A PALTRY DRYLINE EVOLVE IN THE ROLLING
PLAINS BEHIND THE DEPARTING SURFACE HIGH. QUALITY RETURN FLOW
HOWEVER IS NOT EXPECTED UNTIL SATURDAY AT WHICH POINT STRONGER
WESTERLY WINDS ALOFT BEHIND THE UPPER RIDGE WILL SHUNT MUCH OF
THIS SHALLOW MOISTURE OUT OF ALL BUT OUR FAR EASTERN COLUMN OF
COUNTIES. A MINOR SHORT WAVE TROUGH IS STILL PROGGED TO SLIDE
THROUGH THIS STRONGER WESTERLY FLOW BY SAT NIGHT/SUN MORNING
ACCOMPANIED BY PERHAPS EVEN DRIER AND WARMER CONDITIONS ON
SUNDAY...BUT WILL STICK WITH SLIGHTLY COOLER CONDITIONS AS A
COLD FRONT WILL BE FOUND EDGING PERILOUSLY CLOSE TO OUR NRN
COUNTIES IN THE WAKE OF THIS UPPER IMPULSE.
BY EARLY NEXT WEEK...NO CHANGES ARE WARRANTED ATTM AS MODELS ARE
NOW IN MORE DISAGREEMENT THAN 24 HOURS AGO. WPC CONTINUES TO FAVOR
A SLOWER AND DEEPER LONGWAVE TROUGH EVOLVING IN THE GREAT BASIN
AND FOUR CORNERS REGION BY THIS TIME. ONLY SIMILARITY AMONG THE
CURRENT ECMWF AND GFS IS THAT THIS WAVE WOULD BE OPEN AND
PROGRESSIVE...THOUGH SIGNIFICANT DIFFERENCES EMERGE IN THE TIMING
OF SAID WAVE AND HOW MUCH CP AIR IS DRAWN SOUTHWARD FOLLOWING ITS
PASSAGE. WOULD STILL EXPECT A SEMI-ACTIVE DRYLINE TO UNFOLD NEAR
THE FRINGES OF OUR EASTERN COUNTIES AS EARLY AS MON AND PERHAPS
LINGERING INTO TUE UNDERNEATH AN INCREASINGLY UNSETTLED SWLY UPPER
FLOW REGIME. THE GEFS MEAN AND EVEN THE CMC INDICATE SUCH A
SCENARIO THAT AS OF YESTERDAY WAS FAVORED BY THE ECMWF...BUT WILL
AWAIT LATER MODEL RUNS BEFORE COMMITTING TO ANY CHANGES STILL SO
MANY PERIODS OUT.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 46 32 68 43 76 / 40 10 0 0 0
TULIA 41 32 67 43 77 / 40 10 0 0 0
PLAINVIEW 41 34 68 44 77 / 30 10 0 0 0
LEVELLAND 48 34 70 46 81 / 30 10 0 0 0
LUBBOCK 43 35 70 45 79 / 30 10 0 0 0
DENVER CITY 51 34 70 47 82 / 20 10 0 0 0
BROWNFIELD 48 35 70 46 82 / 30 10 0 0 0
CHILDRESS 43 35 64 43 78 / 40 20 0 0 0
SPUR 41 35 68 45 81 / 30 10 0 0 0
ASPERMONT 43 37 66 44 80 / 30 10 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07/93
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
900 PM CDT THU APR 4 2013
.UPDATE...
WEAKENING COLD FRONT EXTENDS FROM MISSOURI/IOWA BORDER TO CHICAGO
AREA...WITH WINDS HAVING TURNED NORTHWEST ACROSS MOST OF
WISCONSIN. OBSERVED 925 MB TEMPS OF 5C AT GRB AND 9C AT DVN
SUPPORTED THE UPPER 50S THAT WE SAW THIS AFTERNOON IN SOUTHERN
WISCONSIN. COLD ADVECTION EXPECTED THROUGH 18Z FRIDAY...WITH
LATEST RAP BRINGING 925 MB TEMPS DOWN TO ABOUT -3C AT MSN/MKE BY
12Z. SHOULD BE ENOUGH WIND AND MIXING TO PREVENT STRONG
RADIATIONAL COOLING...SO ISOTHERMALLY UPPER 20S FOR MOST AREAS
AWAY FROM THE LAKE LOOKS GOOD.
&&
.AVIATION/06Z TAFS/...
LIGHT NORTHWEST WINDS EXPECTED TO GRADUALLY TURN TO THE NORTHEAST
BY MORNING BEFORE BECOMING EASTERLY LATER FRIDAY. MID AND HIGH
CLOUDS IN WARM ADVECTION REGIME SHOULD ARRIVE DURING THE AFTERNOON
AND THEN THICKEN FRIDAY EVENING. MOST OF THE SIGNIFICANT
PRECIPITATION SHOULD BE ACROSS CENTRAL WISCONSIN...BUT ENOUGH LIFT
FOR LIGHT PRECIPITATION ACROSS THE SOUTH. IT WILL BE COLD ALOFT
BUT MARGINAL AT THE SURFACE BUT DRY AIRMASS WILL ALLOW
EVAPORATIONAL COOLING SO CHANCE OF RAIN...SLEET...AND SNOW DURING
THE NIGHT THOUGH PRECIPITATION SHOULD BE PRETTY LIGHT. BEST
CHANCES IN NORTHERN TAF SITES AND LESS CHANCE AT KENW.
&&
.MARINE...
LOW PRESSURE TRACKING ACROSS CENTRAL WISCONSIN ON SATURDAY WILL
INDUCE 10-13 MB PRESSURE FALLS DURING THE DAY...WITH STRONG
SOUTHERLY GRADIENT RESULTING IN SMALL CRAFT ADVISORY CONDITIONS.
WITH 925 MB WINDS AROUND 50 KNOTS SOME CONCERN FOR GALE FORCE
GUSTS BUT COLD LAKE AND STABLE CONDITIONS WILL LIMIT MIXING OVER
THE WATER.
&&
.PREV DISCUSSION... /ISSUED 335 PM CDT THU APR 4 2013/
SHORT TERM...
TONIGHT...FORECAST CONFIDENCE HIGH.
THE LINE OF VERY LIGHT RAIN SHOWERS ASSOCIATED WITH A SURFACE
TROUGH...WEAK 700MB FRONTOGENESIS AND OMEGA...AND A VERY WEAK 500MB
SHORTWAVE IS DISSIPATING AS IT MOVES INTO SOUTH CENTRAL WI THIS
AFTERNOON DUE TO WEAKENING SURFACE CONVERGENCE AND UPPER DYNAMICS.
THE LOW LEVELS ARE VERY DRY AND CLOUD BASES ARE 6000 TO 8000 FEET IN
WESTERN WI...SO THE MOST WE WILL SEE WITH THIS FEATURE WILL BE A FEW
SPRINKLES.
SKIES WILL CLEAR BEHIND THE FRONT...AND WINDS WILL TURN TO THE NORTH
IN THE EVENING. HIGH PRESSURE OVER THE DAKOTAS WILL SLIP DOWN ACROSS
WISCONSIN TONIGHT AND FRIDAY. WINDS WILL BECOME LIGHT TOWARD FRIDAY
MORNING.
LEANED TOWARD COOLER GUIDANCE LIKE THE NAM...MOS GUIDANCE AND
CONSENSUS OF RAW MODELS FOR MIN TEMPS TONIGHT GIVEN THE DRY AIR...
CLEAR SKIES AND LIGHTER WINDS.
FRIDAY...FORECAST CONFIDENCE HIGH.
LIGHT NORTHEAST MORNING WINDS WILL QUICKLY INCREASE OUT OF THE EAST
MID FRIDAY MORNING WITH A LAKE BREEZE COMPONENT AS HIGH PRESSURE
DRIFTS ACROSS LAKE MICHIGAN. MID AND HIGH CLOUDS WILL GRADUALLY
INCREASE THROUGH THE DAY. HIGH TEMPERATURES ARE EXPECTED TO REACH 50
WELL INLAND FROM THE LAKE AS 925MB TEMPS RISE TO 2C TO 3C.
ADDED A CHANCE FOR LIGHT RAIN BEGINNING AFTER 21Z FRI AFTERNOON TO
THE WESTERN FORECAST AREA DUE TO A RATHER STRONG-LOOKING WAVE OF
850-600MB FRONTOGENESIS AND WARM AIR ADVECTION AHEAD OF THE
DEVELOPING SURFACE LOW OVER THE PLAINS.
FRIDAY NIGHT THROUGH SUNDAY...FORECAST CONFIDENCE MEDIUM
A SHORTWAVE TROUGH WILL MOVE FROM THE NRN ROCKIES TO SD AND NE BY
12Z SAT WITH THE ASSOCIATED SFC LOW AROUND SIOUX FALLS SD. WELL
AHEAD OF THIS SYSTEM...THE 700 MB BAROCLINIC ZONE WILL MOVE ACROSS
SRN WI FRI EVENING FOLLOWED BY A 50 KT SWLY LOW LEVEL JET AND
ASSOCIATED THETA E ADVECTION. MOST MODELS HANG ONTO DRY AIR IN THE
LOW LEVELS BUT GIVEN AFOREMENTIONED FEATURES AND GOOD LIFT...DO
EXPECT LIGHT PCPN FOR FRI NT. WET BULB TEMPS WOULD SUPPORT A MIX
OF RAIN...SNOW...AND SLEET FOR MOST OF THE AREA WITH A PERIOD OF
ALL SNOW IN THE NRN CWA. MIXED PCPN WOULD EVENTUALLY CHANGE TO ALL
RAIN BY SAT AM. ONLY LIGHT SNOW ACCUMS ARE EXPECTED.
THE LOW PRESSURE AREA WILL THEN MOVE ACROSS CENTRAL WI SAT
AFTERNOON OR EVENING WITH THE SHORTWAVE TROUGH TRACKING ACROSS SRN
WI OR NRN IL. PWS WILL INCREASE TO ONE INCH WITH VERY MINOR CAPE
NOTED ON SOUNDINGS. FORECASTING LIKELY TO CATEGORICAL SHOWERS WITH
TOTAL QPF WITH THIS SYSTEM RANGING FROM ONE HALF INCH IN THE FAR
NRN CWA TO AROUND 0.20 INCHES NEAR THE IL BORDER. WEAK COLD
ADVECTION ON NWLY WINDS WILL FOLLOW FOR SAT NT. HIGH PRESSURE AND
PLEASANT SPRING WX TO PREVAIL ON SUNDAY.
ABOVE NORMAL TEMPS FOR SAT AS WARM FRONT MOVES INTO FAR SRN WI.
SEASONAL TEMPS THEN EXPECTED FOR SUNDAY BUT COOL TEMPS FOR FAR ERN
WI DUE TO THE LAKE BREEZE.
LONG TERM...
SUNDAY NIGHT THROUGH THURSDAY...FORECAST CONFIDENCE LOW TO MEDIUM
AN ACTIVE AND WET WEEK IS EXPECTED BUT MODELS DIFFER ON DETAILS.
A SHORTWAVE TROUGH AND WAVE OF LOW PRESSURE WILL TRACK FROM THE
CENTRAL PLAINS TO ACROSS NRN IL OR SRN WI FOR SUN NT AND MON. GOOD
CHANCES OF RAIN ARE FORECAST ALONG WITH A MIX OF RAIN AND SNOW IN
THE FAR NRN CWA.
A LARGE POLAR TROUGH WILL SETTLE OVER THE DESERT SW AND EVENTUALLY
MOVE INTO THE PLAINS BY THU. CYCLOGENESIS IS EXPECTED WITH A WEST
TO EAST WARM FRONT OR STATIONARY FRONT EXTENDING ACROSS THE
CENTRAL USA AND POSSIBLY AS FAR NORTH AS THE GREAT LAKES AT TIMES.
GOOD CHANCES OF RAIN ARE FORECAST THROUGHOUT THE WEEK WITH CHANCES
OF RAIN AND SNOW TOWARD CENTRAL WI. NORMAL TO BELOW NORMAL TEMPS
ARE EXPECTED.
AVIATION/00Z TAFS/...
VFR CONDITIONS EXPECTED THROUGH THE PERIOD. IT WILL BE A MAINLY DRY
FRONTAL PASSAGE THROUGH SOUTHEAST WI LATE THIS AFTERNOON. ONLY A FEW
SPRINKLES ARE POSSIBLE. WINDS WILL GRADUALLY VEER FROM SOUTHWEST TO
WEST AND WEAKEN THIS AFTERNOON...AND THEN VEER TO NORTHWEST LATE
THIS AFTERNOON AND NORTH THIS EVENING.
A LAKE BREEZE WILL DEVELOP BY MID MORNING AND WINDS WILL BECOME
EASTERLY ACROSS ALL OF SOUTHERN WI BY EARLY AFTERNOON AS HIGH
PRESSURE DRIFTS ACROSS LAKE MICHIGAN.
RAIN CHANCES WILL INCREASE WEST OF MADISON LATE FRIDAY AFTERNOON AND
OVER ALL OF SOUTHERN WI FRIDAY NIGHT AS LOW PRESSURE TRACKS FROM THE
PLAINS TO THE GREAT LAKES REGION. THERE IS A CHANCE FOR SNOW WITH
THE RAIN FRIDAY EVENING AND OVERNIGHT PRIMARILY FROM MADISON TO
MILWAUKEE AND NORTH.
MARINE...
GUSTY WINDS NORTH OF PORT WASHINGTON WILL DIMINISH BELOW SMALL CRAFT
ADVY CRITERIA ON SCHEDULE LATE THIS AFTERNOON AS THE FRONT PASSES
THROUGH...SO WILL ALLOW IT TO EXPIRE.
A LAKE BREEZE WILL DEVELOP BY MID FRIDAY MORNING AS HIGH PRESSURE
DRIFTS ACROSS LAKE MICHIGAN. LOOK FOR INCREASING SOUTHEAST WINDS AND
SUBSEQUENT WAVES AHEAD OF THE NEXT LOW PRESSURE SYSTEM DEVELOPING IN
THE PLAINS AND HEADING TOWARD THE GREAT LAKES FOR THE WEEKEND. A
SMALL CRAFT ADVISORY MAY BE NEEDED.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...CRAVEN
TONIGHT/FRIDAY AND AVIATION/MARINE...MRC
FRIDAY NIGHT THROUGH THURSDAY...GEHRING
AREA FORECAST DISCUSSION
NWS MIAMI FL
343 AM EDT FRI APR 5 2013
.DISCUSSION...
AN MCS WAS MOVING ACROSS THE EASTERN GULF AND SOUTH FLORIDA EARLY
THIS MORNING. AN UPPER LEVEL LOW WAS MOVING EAST ACROSS
ALABAMA...WITH BROAD SURFACE LOW PRESSURE AREAS FROM NORTHERN
FLORIDA NORTHWARD TO OFF THE COAST OF NORTH CAROLINA. GLOBAL
MODELS ARE NOT HANDLING THE CURRENT SITUATION WELL...SO FOLLOWED
CLOSER TO THE HRRR OUTPUT THROUGH THE AFTERNOON.
THE ATMOSPHERE OVER SOUTH FLORIDA IS EXPECTED TO BECOME WORKED
OVER FROM THIS MCS...WITH MUCH MORE STABLE CONDITIONS. CLOUD
COVER WILL BLANKET THE REGION FOR MUCH OF THE DAY. SO THE SEVERE
THREAT APPEARS TO HAVE DIMINISHED...WITH THE LAST STRONG STORMS
ACROSS THE FAR SOUTHEASTERN PORTIONS OF MIAMI DADE COUNTY EARLY
THIS MORNING. SO LIGHT/MODERATE RAIN WITH A FEW EMBEDDED
THUNDERSTORMS ARE ALL THAT IS EXPECTED THROUGH THE MID/LATE
AFTERNOON...BEFORE THE COLD FRONT PUSHES THROUGH THE REGION.
UNDERCUT MAV/MET TEMPERATURES AT MOST LOCATIONS TODAY DUE TO THE
EXPECTED CLOUD COVER AND RAIN.
A FEW LINGERING SHOWERS ARE POSSIBLE INTO THE EARLY EVENING.
OTHERWISE...DRIER AND COOLER CONDITIONS ARE EXPECTED OVER SOUTH
FLORIDA TONIGHT. THE WEEKEND LOOKS LIKE IT WILL BE A PLEASANT
ONE WITH TEMPERATURES NEAR NORMAL FOR EARLY APRIL. A LIGHT TO
MODERATE NORTHEASTERLY FLOW WILL PREVAIL ON SATURDAY...WITH WINDS
SHIFTING TO THE EAST ON SUNDAY AS HIGH PRESSURE MOVES INTO THE
WESTERN ATLANTIC OFF THE EASTERN CONUS.
HIGH PRESSURE WILL REMAIN OVER THE WESTERN ATLANTIC THROUGH THE
MIDDLE OF THE WEEK...WITH LOW LEVEL MOISTURE RETURNING TO THE
REGION. HIGHS WILL REMAIN IN THE LOW 80S EAST TO THE MID TO UPPER
80S TOWARD THE GULF COAST. OVERNIGHT LOW TEMPERATURES WILL
INCREASE TO THE LOWER 70S FOR THE EAST COAST METRO AREAS. A FEW
STREAMER SHOWERS WILL BE POSSIBLE EACH DAY FROM TUESDAY THROUGH
THE END OF THE WEEK.
&&
.AVIATION...06Z TAFS.
MATURE MCS MOVING ACROSS THE EASTERN GULF AND
ACROSS SOUTH FLORIDA EARLY THIS MORNING. STRONG TO SEVERE STORMS
ARE POSSIBLE AT KFXE SOUTHWARD ON THE EAST COAST OVER THE NEXT FEW
HOURS. PREVAILING MVFR CONDITIONS ARE EXPECTED FOR MOST OF THE
EAST COAST TAF SITES THROUGH THE OVERNIGHT HOURS...WITH IFR
CONDITIONS POSSIBLE IN THUNDERSTORMS. KAPF IS IN THE RAIN SHIELD
ON THE NORTH SIDE OF THE MCS...AND LIGHT/MODERATE RAIN WITH A FEW
HIGH BASED LIGHTNING STRIKES WILL CONTINUE THROUGH THE MORNING
HOURS. LIGHT/MODERATE RAIN IS EXPECTED AFTER 10-12Z ACROSS THE
REGION AS THE MCS MOVES THROUGH AND SOUTH FLORIDA GETS WORKED
OVER. AT THIS TIME IS IT DIFFICULT TO SAY WHETHER THERE WILL BE
ANY REGENERATION OF THUNDERSTORMS BY THE AFTERNOON HOURS DUE TO
ALL THE CLOUD COVER. BASED OFF OF LATEST GUIDANCE...WILL ONLY SHOW
RAIN AFTER 12-14Z...WITH CONDITIONS IMPROVING BY MID/LATE
AFTERNOON. THE FRONT IS EXPECTED TO PASS THROUGH THE REGION
18-21Z...WITH LIGHT/MODERATE NORTHWESTERLY FLOW THROUGH THE END OF
THE TAF PERIOD.
&&
.MARINE...
LATEST GUIDANCE INDICATES THAT WINDS ACROSS THE LOCAL GULF AND
ATLANTIC WATERS COULD REACH AROUND 20 KNOTS THIS MORNING AND SEAS
ACROSS THE OFF SHORE GULF WATERS COULD REACH NEAR 7 FEET. A SMALL
CRAFT ADVISORY IS IN EFFECT THROUGH 00Z THIS EVENING FOR ALL OF
THE LOCAL WATERS. A COLD FRONT WILL MOVE THROUGH THE REGION LATE
THIS AFTERNOON...WITH WINDS SHIFTING TO THE NORTHWEST BEHIND THE
FRONT. NORTHEAST WINDS 15-20 KNOTS ARE EXPECTED ON SATURDAY...WITH
EASTERLY WINDS 10-15 KNOTS ON SUNDAY. EAST TO SOUTHEAST WINDS ARE
THEN EXPECTED THROUGH THE WEEK AS HIGH PRESSURE BUILDS ACROSS THE
WESTERN ATLANTIC.
&&
.FIRE WEATHER...
MUCH NEEDED RAINFALL WILL CONTINUE TO FALL ACROSS MUCH OF THE
REGION THROUGH THE DAY TODAY. A FEW EMBEDDED THUNDERSTORMS ARE
POSSIBLE INTO THE AFTERNOON. A COLD FRONT WILL MOVE THROUGH THE
REGION LATE THIS AFTERNOON INTO THIS EVENING...WITH DRIER AND
COOLER CONDITIONS EXPECTED TONIGHT. MINIMUM RELATIVE HUMIDITY
VALUES AND SATURDAY ARE EXPECTED TO REMAIN JUST ABOVE CRITICAL
VALUES ACROSS THE INTERIOR WEST. HIGH PRESSURE WILL THEN BUILD
ACROSS THE WESTERN ATLANTIC SUNDAY THROUGH THE MIDDLE OF THE
WEEK...WITH LOW LEVEL MOISTURE RETURNING TO SOUTH FLORIDA.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 79 61 77 67 / 60 10 0 -
FORT LAUDERDALE 78 65 79 69 / 70 10 0 -
MIAMI 78 64 79 68 / 70 20 0 -
NAPLES 75 58 81 62 / 50 10 0 -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR BISCAYNE
BAY-COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL
OUT 20 NM-COASTAL WATERS FROM JUPITER INLET TO DEERFIELD
BEACH, FL OUT 20 NM-LAKE OKEECHOBEE-WATERS FROM DEERFIELD
BEACH TO OCEAN REEF, FL EXTENDING FROM 20 NM TO THE
TERRITORIAL WATERS OF THE BAHAMAS-WATERS FROM JUPITER INLET
TO DEERFIELD BEACH, FL EXTENDING FROM 20 NM TO 60 NM.
GM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR COASTAL
WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT
20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL
EXTENDING FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1130 PM CDT THU APR 4 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 306 PM CDT THU APR 4 2013
LIGHT SURFACE PRESSURE GRADIENT IS EVIDENT IN 20Z RAP ANALYSIS. THIS
LIGHT PRESSURE GRADIENT IS RESPONSIBLE FOR LIGHT WINDS WHICH ARE
EVIDENT IN SURFACE OBSERVATIONS ACROSS THE FORECAST AREA THIS
AFTERNOON. EXPECT THESE LIGHT WINDS TO EVENTUALLY SHIFT TO THE SOUTH
OVERNIGHT TONIGHT AS A SURFACE LOW COMES INTO FORMATION OVER THE
HIGH PLAINS. SOUTHERLY WINDS WILL INCREASE THROUGH THE DAY ON FRIDAY
TO AROUND 20 TO 25 MPH...WITH GUSTS TO AROUND 30 MPH. DEEP MIXING
WILL CAUSE ALLOW FOR LOW LEVEL WINDS AROUND 850 MB TO COME TO THE
SURFACE...WHICH MAY BRING WARMER/DRYER CONDITIONS AND STRONGER WIND
GUSTS. THIS WILL HAVE FIRE WEATHER IMPLICATIONS...WHICH ARE
DISCUSSED IN THE FIRE WEATHER DISCUSSION BELOW. AT THIS TIME EXPECT
VERY HIGH FIRE DANGER FOR MOST OF THE AREA THROUGH THE DAY ON
FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 306 PM CDT THU APR 4 2013
FRIDAY NIGHT THROUGH SUNDAY...FRIDAY NIGHT LEE SIDE LOW PRESSURE
DEEPENS OVER THE HIGH PLAINS INCREASING THE PRESSURE GRADIENT
ACROSS THE AREA. THEREFORE THE WINDS WILL CONTINUE TO BE GUSTY
THROUGH THE OVERNIGHT HOURS ESPECIALLY ACROSS EASTERN KANSAS. THIS
WILL KEEP LOW TEMPERATURES FRIDAY NIGHT IN THE LOW 50S. A
SOUTHWESTERLY LOW LEVEL JET INCREASES FRIDAY NIGHT BRINGING
LIMITED MOISTURE TO THE REGION. MEANWHILE A SHORTWAVE ADVANCES
EASTWARD INTO NEBRASKA AND EVENTUALLY IOWA ON SATURDAY. IT APPEARS
THAT THE STRONGER LIFT ASSOCIATED WITH THE WAVE WILL BE NORTH OF
THE AREA FRIDAY NIGHT AND SATURDAY MORNING. THERE IS SLIGHT CHANCE
OF SOME WEAK LIFT EXTENDING SOUTH INTO KANSAS SO COULD NOT RULE
OUT AN ISOLATED SHOWER FRIDAY NIGHT. A WEAK COLD FRONT ASSOCIATED
WITH THE WAVE WILL PUSH SOUTHWARD THROUGH THE AREA DURING THE DAY
ON SATURDAY SHIFTING THE WINDS TO THE NORTH. THE FRONT WILL
RETREAT BACK TO THE NORTH ON SUNDAY AND SETS UP SOMEWHERE IN
NORTHEAST KANSAS. A WEAK SHORTWAVE EMBEDDED IN THE ZONAL MID LEVEL
FLOW PROGRESSES EASTWARD ACROSS KANSAS DURING THE DAY PROVIDING
LAGER SCALE LIFT. SOUTHERLY LOW LEVEL FLOW WILL INCREASE THE
MOISTURE RETURN ACROSS THE AREA AS ML CAPE VALUES APPROACH 500
J/KG AIDING IN THUNDERSTORM DEVELOPMENT. MID LEVEL FLOW ALSO
INCREASES SUNDAY WITH 0-6 KM BULK SHEAR VALUES AROUND 40 KTS WHICH
SUPPORTS THE CHANCE OF STRONGER ORGANIZED THUNDERSTORMS SUNDAY
AFTERNOON AND OVERNIGHT.
EXTENDED FORECAST (SUN NIGHT-THURS)...AN ACTIVE PATTERN SETTING UP
THROUGH THIS PERIOD...AND SEVERE WEATHER APPEARS INCREASINGLY
LIKELY....HOWEVER TIMING AND PLACEMENT REMAINS SOMEWHAT
UNCERTAIN. SUNDAY NIGHT THE GFS AND A SOMEWHAT FASTER EC BRING A
SHORTWAVE OVER THE WARMFRONT PROGGED E/W OVER OUR AREA...WITH THE
EC HOLDING THE FRONT FARTHER SOUTH THAN THE GFS. ENOUGH CAPE AND
SHEAR PRESENT THAT SOME OF THE STORMS OVERNIGHT COULD BRING HAIL.
THE ENSUING WEATHER FOR MONDAY WILL BE DEPENDENT ON HOW FAR NORTH
THE WARMFRONT LIFTS DURING THE DAY. EC AND GFS BOTH BREAK OUT
CONVECTION NEAR THE BOUNDARY AND LESS SO IN THE WARM SECTOR MONDAY
EVENING THROUGH THE MORNING HOURS ON TUESDAY. SEVERE WEATHER
POTENTIAL CONTINUES TO INCREASE INTO TUESDAY AND TUESDAY
AFTERNOON AS WESTERN TROF APPROACHES...AND SHEAR AND INSTABILITY
ALSO INCREASE AND MOVE NORTH ACROSS THE CWA WITH THE WARM SECTOR.
DIFFERENCES INCREASE BEYOND TUESDAY AS GFS MOVES THE COLDFRONT
THROUGH QUICKLY WITH EC DROPPING A CLOSED UPPER LOW ACROSS EASTERN
KANSAS AND THE FRONT MOVING THROUGH WEDNESDAY EVENING. WHILE
WED/THURS WILL BRING A COOL END OF THE WEEK...MUCH UNCERTAINTY
WITH PRECIP AMOUNTS AND TYPES. 67
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1129 PM CDT THU APR 4 2013
VFR EXPECTED THROUGH THE PERIOD. WINDS WILL BE THE MAIN CONCERN
FOR THE FORECAST AS THEY WILL BEGIN TO INCREASE BY 16Z TO AROUND
16 KTS WITH GUSTS AS HIGH AS 29 KTS IN THE AFTERNOON. PRESSURE
GRADIENT WILL REMAIN TIGHT EVEN AFTER SUNSET WHERE THE GUSTS MY
SUBSIDE AFTER 02Z...BUT WINDS WILL REMAIN AROUND 15-19 KTS.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...LEIGHTON
LONG TERM...67
AVIATION...53
AREA FORECAST DISCUSSION...UPDATED
NWS GAYLORD MI
122 AM EDT FRI APR 5 2013
.SYNOPSIS...
ISSUED AT 344 PM EDT THU APR 4 2013
A COLD FRONT IS MOVING THROUGH NORTHERN MICHIGAN...BRINGING A
PERIOD OF LIGHT RAIN AND SNOW FOR THIS AFTERNOON AND TONIGHT.
SETTLED WEATHER WILL RETURN FOR A SHORT TIME ON FRIDAY...BEFORE
ANOTHER STORM SYSTEM MOVES INTO NORTHERN MICHIGAN...BRINGING RAIN
AND SNOW MIXED FOR SATURDAY INTO SUNDAY.
&&
.UPDATE...
ISSUED AT 1246 AM EDT FRI APR 5 2013
CHANGES THIS HOUR: ONLY CHANGE AT THIS TIME IS TO END FOG MENTION
A LITTLE EARLIER OVERNIGHT AS VERY DRY UPSTREAM AIRMASS HAS
BROUGHT A QUICK END TO WHAT WAS LOCALLY DENSE FOG LATE LAST
EVENING. SHSN CHANCES TOWARDS DAYBREAK STILL LOOKING RATHER LOW
GIVEN THE PAUCITY OF MOISTURE UPSTREAM...BUT LOW END POPS STILL
ARE WARRANTED IN FAVORED NNW FLOW AREAS.
UPDATE ISSUED AT 1115 PM EDT THU APR 4 2013
ALL SYNOPTICALLY DRIVEN SNOW HAS EXITED OUT OF OUR CWA LATE THIS
EVENING ALONG THE DEPARTING COLD FRONT. RESIDUAL SCT/BKN LOW
CLOUDS BEHIND THE FRONT ARE SHOWING SIGNS OF BECOMING LAKE
ENHANCED PER LATEST 11U-3.9U SATELLITE LOOP. LAST FEW FRAMES FROM
KMQT 88D SHOWS THE BEGINNINGS OF SOME VERY LIGHT LAKE EFFECT
FLURRIES/SNOW SHOWERS THANKS TO CAA AND N/NW FLOW OFF OF LAKE
SUPERIOR. AIRMASS FILTERING IN BEHIND THE COLD FRONT IS QUITE
DRY...BUT WITH 850 MB TEMPS DROPPING INTO THE MID TEENS...EXPECT
AT LEAST SOME N/NW FLOW LAKE FLURRIES/LIGHT SNOW SHOWERS WILL
DEVELOP OVERNIGHT. LOW CLOUDS WILL DIMINISH OVERNIGHT AWAY FROM ANY
LAKE INFLUENCES AS DRIER SYNOPTIC AIR ADVECTS INTO THE REGION.
ALSO EXPECT AREAS OF FOG THAT DEVELOP ACROSS PORTIONS OF NRN LWR
MICHIGAN WILL EVENTUALLY DISSIPATE LATE TONIGHT/EARLY FRIDAY
THANKS TO THAT DRIER AIR. UPSTREAM DWPTS IN THE 20S CERTAINLY
SUPPORTS OVERNIGHT LOWS IN THE 20S.
UPDATE ISSUED AT 700 PM EDT THU APR 4 2013
LINE OF RAIN/SNOW SHOWERS ACCELERATED SE EARLY THIS EVENING IN
RESPONSE TO A 125 KT 300 MB JET MAX DIGGING INTO THE WRN GREAT
LAKES REGION. HAVE MADE SEVERAL MODIFICATIONS TO TIMING AS A
RESULT...AND ALL PRECIP ASSOCIATED WITH THE FRONT SHOULD CLEAR OUR
CWA WITHIN THE NEXT HOUR OR SO. SOME CLEARING WILL TAKE PLACE...
EXPECT FOR LOCATIONS DOWNSTREAM OF LAKES SUPERIOR AND MICHIGAN
UNDER THE DIRECTION OF N/NW FLOW. LAKE CLOUDS AND SOME
FLURRIES/LIGHT SNOW SHOWERS SHOULD DEVELOP WITHIN THESE AREAS AND
PERSIST THE REST OF THE NIGHT AND INTO FRIDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 344 PM EDT THU APR 4 2013
THE CURRENT RADAR SHOWS A NARROW BAND OF PCPN SLOWLY DROPPING SOUTH
ACROSS NORTHERN LOWER MICHIGAN. THIS NARROW AREA OF PRECIPITATION IS
THE RESULT OF A COLD FRONT SINKING SOUTH OVER THE REGION. VIS SAT
AND SFC OBS SHOW LIMITED MOISTURE EITHER SIDE OF THE BOUNDARY...WITH
MOSTLY SUNNY SKIES OVER MUCH OF CENTRAL AND SOUTHERN MICHIGAN. SUN
OVER THE SRN CWA FROM EARLIER TODAY...HAS ALLOWED AFTERNOON TEMPS IN
THESE AREAS TO WARM QUICKLY INTO THE MID AND UPPER 40S...WHILE
TEMPS REMAIN IN THE 30S OVER ERN UPPER NORTH OF THE BOUNDARY.
OVERALL THE MAIN FORECAST CONCERNS TONIGHT THROUGH FRIDAY WILL BE
TIMING AND TYPE OF PCPN TONIGHT WITH THE APPROACHING FRONT...ALONG
WITH ANY LAKE INDUCED SNOWS FRIDAY ON THE BACKSIDE OF THE COLD
FRONT.
THE STORM SYSTEM CURRENTLY MOVING ACRS ONTARIO WILL QUICKLY EXIT
INTO QUEBEC THIS EVENING. A COLD FRONT ASSOCIATED WITH THIS SYSTEM...
WILL CONT TO DROP SOUTH ACRS NRN LWR MI THIS EVENING BEFORE EXITING
EAST. EXPECT THE FRONT TO HAVE CLEARED NORTHERN LOWER MICHIGAN
BTWN 03Z AND 06Z. THE ONLY PCPN ASSOCIATED WITH THIS BOUNDARY HAS
BEEN LOCATED RIGHT ALONG THE FRONT...DUE TO THE EXTREMELY DRY AIR
LOCATED OVER THE GREAT LAKES. HOWEVER SFC DEW PTS EVENTUALLY
INCREASED FROM THE TEENS INTO THE MID 20S OVER THE STRAITS AS THE
FRONT APPROACHED (ENOUGH TO GENERATE PCPN). HOWEVER PCPN TYPE AND
CHC OVER THE REST OF THE CWA WILL BE DIFFICULT THIS EVENING AS THE
FRONT DIPS SOUTH. TO THIS POINT...ALL OF THE PCPN HAS BEEN IN THE
FORM OF SNOW OVER ERN UPPER AND THE STRAITS. THE LATEST RUC MODEL
SOUNDINGS SHOW AN INVERTED V SIGNATURE IN THE LOWEST LAYERS FROM
GAYLORD SOUTH TO THE SAGINAW BAY THIS EVENING...WITH OTHERWISE
EXTREMELY DRY AIR ABOVE 850MB. ADDING COMPLICATIONS TO PCPN TYPE
THIS EVENING IS THE VERTICAL TEMP PROFILES...AS MOST OF NRN LWR
WARMED WELL INTO THE MID AND UPPER 40S DUE TO SOUTHWEST WINDS AND
FULL SUN IN ADVANCE OF THE FRONT. HOWEVER PROGGED 850MB WET BULB TEMPS
WOULD SUGGEST ENOUGH EVAP COOLING WITH ONSET OF ADVANCING MSTR TO AT
LEAST MENTION A RAIN/SNOW MIX. OVERALL WILL CONTINUE THE LATEST
TREND OF CHC POPS RAIN/SNOW MIXED OVER THE SRN HALF OF THE CWA AND
SAGINAW BAY INTO THIS EVENING.
COLDER AIR AND NORTHWEST FLOW RE-SETTLES INTO THE REGION OVERNIGHT
AND FRIDAY ON THE BACK SIDE OF THE EXITING BOUNDARY. 850MB TEMPS
QUICKLY DROP FROM ARND -4C THIS EVENING TO BETWEEN -12C AND -14C BY
12Z FRIDAY. SFC-850MB WINDS TURN FROM THE SOUTHWEST THIS EVENING IN
ADVANCE OF THE BOUNDARY TO NNW FRIDAY. MODEL SOUNDINGS SUGGEST INVERSION
HEIGHTS INCREASING TO NEAR 5K FT WHILE LINGERING LOW LVL MSTR EXTENDS
TO AROUND THE -12C ISOTHERM. OVERALL MENTION CHC POPS IN NORTH FLOW
SNOW BELTS EARLY FRIDAY. OTHERWISE WILL MENTION AT LEAST PARTLY
SUNNY SKIES OVER THE REST OF THE CWA FRIDAY. WILL MENTION COOLER AFTN
TEMPS FRIDAY...RANGING FROM AROUND FREEZING OVER ERN UPPER AND THE
STRAITS TO THE LOWER 40S NEAR SAGINAW BAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 344 PM EDT THU APR 4 2013
LITTLE CHANGE FROM WHAT WAS SEEN YESTERDAY...WITH STILL PLENTY OF
POTENTIAL FOR A VERY ACTIVE NEXT 7 DAYS OF WEATHER AS PERSISTENT
-AO RELAXES AND DEEP SOUTHWEST MOISTURE RICH FLOW DEVELOPS ON
FRONTSIDE OF DIGGING INTERMOUNTAIN WEST ENERGY. BIG WILD CARD
REMAINS POTENTIAL INTERACTION WITH POLAR LOW SET TO ROTATE ACROSS
EASTERN CANADA. EVENTUAL PLACEMENT OF THIS FEATURE WILL BE KEY IN
DETERMINING LOCATION OF INTENSE LOW LEVEL THERMAL BOUNDARY AND
SUBSEQUENT PATHWAY FOR ENERGY ROTATING OUT OF WESTERN TROUGH AXIS.
WHILE ABOVE REMAINS A VERY LOW CONFIDENCE PORTION OF THE
FORECAST...LEAD WAVE APPROACHING THE PACIFIC NORTHWEST (NICELY
ILLUSTRATED ON LATEST WATER VAPOR IMAGERY) NOW WELL AGREED UPON TO
IMPACT OUR WEATHER INTO THE START OF THIS WEEKEND. THIS WAVE WILL
BRING ANOTHER BOUT OF WINTRY WEATHER TO THE NORTH WOODS
SATURDAY...WITH INCREASING CONFIDENCE PARTS OF EASTERN UPPER WILL
SEE A PERIOD OF ACCUMULATING SNOW. FORECAST CONCERNS INITIALLY
DEAL WITH THIS LATTER SYSTEM...SPECIFICALLY SNOWFALL ACCUMULATIONS
FOR EASTERN UPPER. MUCH MORE OF PROBABILISTIC APPROACH TAKING FOR
THE REMAINDER OF THE FORECAST...WITH AT LEAST SOME ATTEMPT AT
ADDRESSING MULTI- PERIOD PRECIP CHANCES AND TEMPERATURE TRENDS.
GUIDANCE HAS LOCKED IN A SOLUTION SENDING PACIFIC NORTHWEST WAVE
RAPIDLY EAST INTO THE NORTHERN PLAIN FRIDAY NIGHT...AND THROUGH
NORTHERN MICHIGAN BY SATURDAY NIGHT. WEAKISH COUPLED JET STRUCTURE
AND LOW LEVEL THERMAL BOUNDARY EXPECTED TO ENTICE RESPECTABLE
SURFACE LOW PRESSURE DEVELOPMENT WITH THIS MID LEVEL WAVE...ITSELF
EXPECTED TO SLICE THROUGH THE HEART OF NORTHERN LOWER MICHIGAN
SATURDAY EVENING. ALTHOUGH WAVE ITSELF AND SURFACE FEATURE NOTHING
TO WRITE HOME ABOUT...ACCOMPANYING DYNAMICS REMAIN IMPRESSIVE INDEED.
MULTI-PERIOD TRENDS CONTINUE TO SUPPORT AGGRESSIVE WAA DRIVEN
DYNAMICS...WITH NEAR 60 KNOT SOUTHWEST FLOW LOW LEVEL JET
PERPENDICULAR TO THE 290K-295K PRESSURE SURFACES. DEEP LAYER FGEN
SIGNAL ALSO PRESENT ALONG RETREATING COLD DOME...COLLOCATED NICELY
WITH MAX WAA UPGLIDE ON NOSE OF LOW LEVEL JET. BEST JUXTAPOSITION OF
THE ABOVE EXPECTED ACROSS FAR NORTHERN LOWER AND AREAS NORTH OF THE
BRIDGE SATURDAY INTO SATURDAY EVENING. SYSTEM HAS A NICE SUBTROPICAL
PACIFIC MOISTURE PLUME ALREADY ASSOCIATED WITH IT...SOME OF WHICH
WILL BE ADVECTED INTO OUR AREA AS SYSTEM APPROACHES. COMBINE THIS
WITH BRIEF WINDOW FOR SOME WESTERN GULF OF MEXICO MOISTURE
CONTRIBUTION...AND PWAT VALUES SURGE TO AOA 0.75 INCHES LEVELS BY
LATER SATURDAY. SAID ISENTROPIC SURFACES ALSO SHOW VERY RESPECTABLE
MOISTURE...WITH MIXING RATIOS EXCEEDING 4 G/KG. LITTLE DOUBT SYSTEM
HAS ALL THE EARMARKS TO BE A RATHER SUBSTANTIAL PRECIP PRODUCER...
ALTHOUGH EXACTLY WHAT TYPE THAT PRECIP TAKES REMAINS A FORMIDABLE
CHALLENGE. WILL USE ROCK-STEADY ECMWF DEPICTIONS FOR THERMAL FIELDS.
THIS CONTINUES TO SUGGEST MAINLY SNOW AT THE ONSET EARLY
SATURDAY...RAPIDLY CHANGING OVER TO LIQUID FROM SOUTHWEST TO
NORTHEAST ACROSS NORTHERN LOWER MICHIGAN DURING THE MORNING. COULD
SEE SOME MINOR SNOW ACCUMULATIONS...ON THE ORDER OF AN INCH OR
SO...ESPECIALLY ACROSS THE HIGHER TERRAIN AREAS. WILL NEED TO WATCH
FOR A PERIOD OF FREEZING RAIN AS WAA STRENGTHENS JUST OFF THE DECK.
THIS SHOULD BE SHORT-LIVED EVENT (IF IT OCCURS AT ALL) AND NOT
WORTHY OF A MENTION IN THE FORECAST. MUCH BIGGER PRECIP TYPE
CHALLENGE ACROSS EASTERN UPPER...WITH STRONG DYNAMICS POSSIBLY
OVERCOMING MARGINAL THERMAL PROFILES TO KEEP PRECIP MAINLY ALL
SNOW...ESPECIALLY ALONG AND NORTH OF M-28. MODEL QPF FIELDS SOMEWHAT
DISCONCERTING...WITH PROGS SUPPORTING A HALF INCH OR MORE OF LIQUID
EQUIVALENT PRECIP BY LATER SATURDAY NIGHT. HEAVIER AMOUNTS NO DOUBT
POSSIBLE GIVEN AMOUNT OF EARLIER MENTIONED DYNAMICS. SNOW RATIOS
WILL NOT BE GREAT...ESPECIALLY SATURDAY AFTERNOON...WHEN SURFACE
READINGS WILL LIKELY EXCEED FREEZING AND HIGH APRIL SUN ANGLE TAKES
HOLD. STILL...COULD EASILY SEE SEVERAL INCHES OF HEAVY WET SNOW
ACCUMULATION BY LATER SATURDAY NIGHT...WITH PERIODS OF HIGH
INTENSITY SNOWFALL. NO HEADLINES FORTHCOMING ON THIS SHIFT...BUT IF
ABOVE COMES TO FRUITION...COULD SEE ADVISORY LEVEL SNOW AMOUNTS FOR
AT LEAST PARTS OF EASTERN UPPER. STAY TUNED! SYSTEM WINDS DOWN
QUICKLY LATE SATURDAY NIGHT...LEAVING BEHIND A DRY SUNDAY AND SUNDAY
EVENING.
CONFIDENCE DROPS REMARKABLY HEADING THROUGH NEXT WORK WEEK...WITH
GUIDANCE STRUGGLING WITH KEY INTERACTIONS TALKED ABOUT IN THE LEAD
PARAGRAPH. PLENTY OF POTENTIAL FOR ADDITIONAL SIGNIFICANT
SYSTEMS...WITH SOME DECENT SUPPORT FOR ONE SUCH SYSTEM TO IMPACT OUR
AREA TO KICK OFF THE WEEK. EXACTLY HOW FAR NORTH THIS SYSTEM RIDES UP
THROUGH THE OHIO VALLEY/SOUTHERN LAKES STILL FAR FROM BEING
DETERMINED. DEPENDING ON SUCH...MAY SEE ENOUGH COLD AIR ALONG THE
NORTHERN PERIPHERY OF ITS PRECIP SHIELD TO SUPPORT SOME WINTRY
WEATHER. NO NEED TO GET TOO SPECIFIC...AND WILL BE FORCED TO RUN
WITH A GUIDANCE CONSENSUS BLEND UNTIL A MORE DETERMINISTIC APPROACH
CAN BE UTILIZED. SAME STORY HEADING THROUGH THE REMAINDER OF THE
WEEK...WITH AGAIN THE POTENTIAL FOR ANOTHER WAVE TO ROTATE NORTHEAST
OUT OF THE SOUTHERN PLAINS. TIMING AND PLACEMENT OF SUCH ALL OVER
THE BOARD...AS IT WILL LIKELY REMAIN WITH BAROCLINIC AXIS SUBJECT TO
MANY CHANGES PER CANADIAN TROUGHING AND PASSAGE OF EARLIER IN THE
WEEK SYSTEMS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 121 AM EDT FRI APR 5 2013
SUMMARY: HIGH PRESSURE WILL BUILD INTO THE GREAT LAKES REGION TODAY
WITH SOME MORNING LAKE ENHANCED CLOUDINESS GIVING WAY TO AMPLE
SUNSHINE UNDER DIMINISHING NORTHWESTERLY WINDS.
RESTRICTIONS: VFR CONDITIONS EXPECTED THROUGH THE UPCOMING TAF
PERIOD. CAN/T RULE OUT A FEW FLURRIES FROM THE PRE-DAWN HOURS
THROUGH MID MORNING AT TVC/MBL...BUT INCOMING AIRMASS IS TOO DRY TOO
SUPPORT SIGNIFICANT SHSN DEVELOPMENT. CIGS MAY DROP TO 3-4KFT FOR A
TIME AT TVC /AND POTENTIALLY AT MBL-PLN/...BUT EXPECT THESE TO
REMAIN VFR BEFORE SCATTERING OUT BY LATE MORNING.
WINDS: NORTHWEST WINDS 5-10KTS WILL CONTINUE THROUGH THE OVERNIGHT
BEFORE INCREASING TO 10G16KTS FOR THE DAY ON FRIDAY WHILE VEERING
NORTH NORTHWEST. WINDS WILL DIMINISH TO CALM OR LIGHT/VARIABLE THIS
EVENING.
&&
.MARINE...
ISSUED AT 344 PM EDT THU APR 4 2013
GUSTY SOUTHWEST WINDS IN ADVANCE OF A FRONTAL BOUNDARY DROPPING
SOUTH OVER NRN MI...WILL TURN NORTHWEST OVERNIGHT AND REMAIN BREEZY
ON THE BACKSIDE OF THE EXITING BOUNDARY. RAIN/SNOW MIXED PCPN WILL
AFFECT NRN MI NEARSHORE WATERS THIS EVENING AS BOUNDARY DROPS
SOUTH...WITH SOME LAKE SNOWS POSSIBLE FRIDAY BEHIND THE FRONT.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...ARNOTT
SYNOPSIS...KAB
SHORT TERM...SWR
LONG TERM...MSB
AVIATION...ARNOTT
MARINE...SWR
AREA FORECAST DISCUSSION...UPDATED
NWS GAYLORD MI
1248 AM EDT FRI APR 5 2013
.SYNOPSIS...
ISSUED AT 344 PM EDT THU APR 4 2013
A COLD FRONT IS MOVING THROUGH NORTHERN MICHIGAN...BRINGING A
PERIOD OF LIGHT RAIN AND SNOW FOR THIS AFTERNOON AND TONIGHT.
SETTLED WEATHER WILL RETURN FOR A SHORT TIME ON FRIDAY...BEFORE
ANOTHER STORM SYSTEM MOVES INTO NORTHERN MICHIGAN...BRINGING RAIN
AND SNOW MIXED FOR SATURDAY INTO SUNDAY.
&&
.UPDATE...
ISSUED AT 1246 AM EDT FRI APR 5 2013
CHANGES THIS HOUR: ONLY CHANGE AT THIS TIME IS TO END FOG MENTION
A LITTLE EARLIER OVERNIGHT AS VERY DRY UPSTREAM AIRMASS HAS
BROUGHT A QUICK END TO WHAT WAS LOCALLY DENSE FOG LATE LAST
EVENING. SHSN CHANCES TOWARDS DAYBREAK STILL LOOKING RATHER LOW
GIVEN THE PAUCITY OF MOISTURE UPSTREAM...BUT LOW END POPS STILL
ARE WARRANTED IN FAVORED NNW FLOW AREAS.
UPDATE ISSUED AT 1115 PM EDT THU APR 4 2013
ALL SYNOPTICALLY DRIVEN SNOW HAS EXITED OUT OF OUR CWA LATE THIS
EVENING ALONG THE DEPARTING COLD FRONT. RESIDUAL SCT/BKN LOW
CLOUDS BEHIND THE FRONT ARE SHOWING SIGNS OF BECOMING LAKE
ENHANCED PER LATEST 11U-3.9U SATELLITE LOOP. LAST FEW FRAMES FROM
KMQT 88D SHOWS THE BEGINNINGS OF SOME VERY LIGHT LAKE EFFECT
FLURRIES/SNOW SHOWERS THANKS TO CAA AND N/NW FLOW OFF OF LAKE
SUPERIOR. AIRMASS FILTERING IN BEHIND THE COLD FRONT IS QUITE
DRY...BUT WITH 850 MB TEMPS DROPPING INTO THE MID TEENS...EXPECT
AT LEAST SOME N/NW FLOW LAKE FLURRIES/LIGHT SNOW SHOWERS WILL
DEVELOP OVERNIGHT. LOW CLOUDS WILL DIMINISH OVERNIGHT AWAY FROM ANY
LAKE INFLUENCES AS DRIER SYNOPTIC AIR ADVECTS INTO THE REGION.
ALSO EXPECT AREAS OF FOG THAT DEVELOP ACROSS PORTIONS OF NRN LWR
MICHIGAN WILL EVENTUALLY DISSIPATE LATE TONIGHT/EARLY FRIDAY
THANKS TO THAT DRIER AIR. UPSTREAM DWPTS IN THE 20S CERTAINLY
SUPPORTS OVERNIGHT LOWS IN THE 20S.
UPDATE ISSUED AT 700 PM EDT THU APR 4 2013
LINE OF RAIN/SNOW SHOWERS ACCELERATED SE EARLY THIS EVENING IN
RESPONSE TO A 125 KT 300 MB JET MAX DIGGING INTO THE WRN GREAT
LAKES REGION. HAVE MADE SEVERAL MODIFICATIONS TO TIMING AS A
RESULT...AND ALL PRECIP ASSOCIATED WITH THE FRONT SHOULD CLEAR OUR
CWA WITHIN THE NEXT HOUR OR SO. SOME CLEARING WILL TAKE PLACE...
EXPECT FOR LOCATIONS DOWNSTREAM OF LAKES SUPERIOR AND MICHIGAN
UNDER THE DIRECTION OF N/NW FLOW. LAKE CLOUDS AND SOME
FLURRIES/LIGHT SNOW SHOWERS SHOULD DEVELOP WITHIN THESE AREAS AND
PERSIST THE REST OF THE NIGHT AND INTO FRIDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 344 PM EDT THU APR 4 2013
THE CURRENT RADAR SHOWS A NARROW BAND OF PCPN SLOWLY DROPPING SOUTH
ACROSS NORTHERN LOWER MICHIGAN. THIS NARROW AREA OF PRECIPITATION IS
THE RESULT OF A COLD FRONT SINKING SOUTH OVER THE REGION. VIS SAT
AND SFC OBS SHOW LIMITED MOISTURE EITHER SIDE OF THE BOUNDARY...WITH
MOSTLY SUNNY SKIES OVER MUCH OF CENTRAL AND SOUTHERN MICHIGAN. SUN
OVER THE SRN CWA FROM EARLIER TODAY...HAS ALLOWED AFTERNOON TEMPS IN
THESE AREAS TO WARM QUICKLY INTO THE MID AND UPPER 40S...WHILE
TEMPS REMAIN IN THE 30S OVER ERN UPPER NORTH OF THE BOUNDARY.
OVERALL THE MAIN FORECAST CONCERNS TONIGHT THROUGH FRIDAY WILL BE
TIMING AND TYPE OF PCPN TONIGHT WITH THE APPROACHING FRONT...ALONG
WITH ANY LAKE INDUCED SNOWS FRIDAY ON THE BACKSIDE OF THE COLD
FRONT.
THE STORM SYSTEM CURRENTLY MOVING ACRS ONTARIO WILL QUICKLY EXIT
INTO QUEBEC THIS EVENING. A COLD FRONT ASSOCIATED WITH THIS SYSTEM...
WILL CONT TO DROP SOUTH ACRS NRN LWR MI THIS EVENING BEFORE EXITING
EAST. EXPECT THE FRONT TO HAVE CLEARED NORTHERN LOWER MICHIGAN
BTWN 03Z AND 06Z. THE ONLY PCPN ASSOCIATED WITH THIS BOUNDARY HAS
BEEN LOCATED RIGHT ALONG THE FRONT...DUE TO THE EXTREMELY DRY AIR
LOCATED OVER THE GREAT LAKES. HOWEVER SFC DEW PTS EVENTUALLY
INCREASED FROM THE TEENS INTO THE MID 20S OVER THE STRAITS AS THE
FRONT APPROACHED (ENOUGH TO GENERATE PCPN). HOWEVER PCPN TYPE AND
CHC OVER THE REST OF THE CWA WILL BE DIFFICULT THIS EVENING AS THE
FRONT DIPS SOUTH. TO THIS POINT...ALL OF THE PCPN HAS BEEN IN THE
FORM OF SNOW OVER ERN UPPER AND THE STRAITS. THE LATEST RUC MODEL
SOUNDINGS SHOW AN INVERTED V SIGNATURE IN THE LOWEST LAYERS FROM
GAYLORD SOUTH TO THE SAGINAW BAY THIS EVENING...WITH OTHERWISE
EXTREMELY DRY AIR ABOVE 850MB. ADDING COMPLICATIONS TO PCPN TYPE
THIS EVENING IS THE VERTICAL TEMP PROFILES...AS MOST OF NRN LWR
WARMED WELL INTO THE MID AND UPPER 40S DUE TO SOUTHWEST WINDS AND
FULL SUN IN ADVANCE OF THE FRONT. HOWEVER PROGGED 850MB WET BULB TEMPS
WOULD SUGGEST ENOUGH EVAP COOLING WITH ONSET OF ADVANCING MSTR TO AT
LEAST MENTION A RAIN/SNOW MIX. OVERALL WILL CONTINUE THE LATEST
TREND OF CHC POPS RAIN/SNOW MIXED OVER THE SRN HALF OF THE CWA AND
SAGINAW BAY INTO THIS EVENING.
COLDER AIR AND NORTHWEST FLOW RE-SETTLES INTO THE REGION OVERNIGHT
AND FRIDAY ON THE BACK SIDE OF THE EXITING BOUNDARY. 850MB TEMPS
QUICKLY DROP FROM ARND -4C THIS EVENING TO BETWEEN -12C AND -14C BY
12Z FRIDAY. SFC-850MB WINDS TURN FROM THE SOUTHWEST THIS EVENING IN
ADVANCE OF THE BOUNDARY TO NNW FRIDAY. MODEL SOUNDINGS SUGGEST INVERSION
HEIGHTS INCREASING TO NEAR 5K FT WHILE LINGERING LOW LVL MSTR EXTENDS
TO AROUND THE -12C ISOTHERM. OVERALL MENTION CHC POPS IN NORTH FLOW
SNOW BELTS EARLY FRIDAY. OTHERWISE WILL MENTION AT LEAST PARTLY
SUNNY SKIES OVER THE REST OF THE CWA FRIDAY. WILL MENTION COOLER AFTN
TEMPS FRIDAY...RANGING FROM AROUND FREEZING OVER ERN UPPER AND THE
STRAITS TO THE LOWER 40S NEAR SAGINAW BAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 344 PM EDT THU APR 4 2013
LITTLE CHANGE FROM WHAT WAS SEEN YESTERDAY...WITH STILL PLENTY OF
POTENTIAL FOR A VERY ACTIVE NEXT 7 DAYS OF WEATHER AS PERSISTENT
-AO RELAXES AND DEEP SOUTHWEST MOISTURE RICH FLOW DEVELOPS ON
FRONTSIDE OF DIGGING INTERMOUNTAIN WEST ENERGY. BIG WILD CARD
REMAINS POTENTIAL INTERACTION WITH POLAR LOW SET TO ROTATE ACROSS
EASTERN CANADA. EVENTUAL PLACEMENT OF THIS FEATURE WILL BE KEY IN
DETERMINING LOCATION OF INTENSE LOW LEVEL THERMAL BOUNDARY AND
SUBSEQUENT PATHWAY FOR ENERGY ROTATING OUT OF WESTERN TROUGH AXIS.
WHILE ABOVE REMAINS A VERY LOW CONFIDENCE PORTION OF THE
FORECAST...LEAD WAVE APPROACHING THE PACIFIC NORTHWEST (NICELY
ILLUSTRATED ON LATEST WATER VAPOR IMAGERY) NOW WELL AGREED UPON TO
IMPACT OUR WEATHER INTO THE START OF THIS WEEKEND. THIS WAVE WILL
BRING ANOTHER BOUT OF WINTRY WEATHER TO THE NORTH WOODS
SATURDAY...WITH INCREASING CONFIDENCE PARTS OF EASTERN UPPER WILL
SEE A PERIOD OF ACCUMULATING SNOW. FORECAST CONCERNS INITIALLY
DEAL WITH THIS LATTER SYSTEM...SPECIFICALLY SNOWFALL ACCUMULATIONS
FOR EASTERN UPPER. MUCH MORE OF PROBABILISTIC APPROACH TAKING FOR
THE REMAINDER OF THE FORECAST...WITH AT LEAST SOME ATTEMPT AT
ADDRESSING MULTI- PERIOD PRECIP CHANCES AND TEMPERATURE TRENDS.
GUIDANCE HAS LOCKED IN A SOLUTION SENDING PACIFIC NORTHWEST WAVE
RAPIDLY EAST INTO THE NORTHERN PLAIN FRIDAY NIGHT...AND THROUGH
NORTHERN MICHIGAN BY SATURDAY NIGHT. WEAKISH COUPLED JET STRUCTURE
AND LOW LEVEL THERMAL BOUNDARY EXPECTED TO ENTICE RESPECTABLE
SURFACE LOW PRESSURE DEVELOPMENT WITH THIS MID LEVEL WAVE...ITSELF
EXPECTED TO SLICE THROUGH THE HEART OF NORTHERN LOWER MICHIGAN
SATURDAY EVENING. ALTHOUGH WAVE ITSELF AND SURFACE FEATURE NOTHING
TO WRITE HOME ABOUT...ACCOMPANYING DYNAMICS REMAIN IMPRESSIVE INDEED.
MULTI-PERIOD TRENDS CONTINUE TO SUPPORT AGGRESSIVE WAA DRIVEN
DYNAMICS...WITH NEAR 60 KNOT SOUTHWEST FLOW LOW LEVEL JET
PERPENDICULAR TO THE 290K-295K PRESSURE SURFACES. DEEP LAYER FGEN
SIGNAL ALSO PRESENT ALONG RETREATING COLD DOME...COLLOCATED NICELY
WITH MAX WAA UPGLIDE ON NOSE OF LOW LEVEL JET. BEST JUXTAPOSITION OF
THE ABOVE EXPECTED ACROSS FAR NORTHERN LOWER AND AREAS NORTH OF THE
BRIDGE SATURDAY INTO SATURDAY EVENING. SYSTEM HAS A NICE SUBTROPICAL
PACIFIC MOISTURE PLUME ALREADY ASSOCIATED WITH IT...SOME OF WHICH
WILL BE ADVECTED INTO OUR AREA AS SYSTEM APPROACHES. COMBINE THIS
WITH BRIEF WINDOW FOR SOME WESTERN GULF OF MEXICO MOISTURE
CONTRIBUTION...AND PWAT VALUES SURGE TO AOA 0.75 INCHES LEVELS BY
LATER SATURDAY. SAID ISENTROPIC SURFACES ALSO SHOW VERY RESPECTABLE
MOISTURE...WITH MIXING RATIOS EXCEEDING 4 G/KG. LITTLE DOUBT SYSTEM
HAS ALL THE EARMARKS TO BE A RATHER SUBSTANTIAL PRECIP PRODUCER...
ALTHOUGH EXACTLY WHAT TYPE THAT PRECIP TAKES REMAINS A FORMIDABLE
CHALLENGE. WILL USE ROCK-STEADY ECMWF DEPICTIONS FOR THERMAL FIELDS.
THIS CONTINUES TO SUGGEST MAINLY SNOW AT THE ONSET EARLY
SATURDAY...RAPIDLY CHANGING OVER TO LIQUID FROM SOUTHWEST TO
NORTHEAST ACROSS NORTHERN LOWER MICHIGAN DURING THE MORNING. COULD
SEE SOME MINOR SNOW ACCUMULATIONS...ON THE ORDER OF AN INCH OR
SO...ESPECIALLY ACROSS THE HIGHER TERRAIN AREAS. WILL NEED TO WATCH
FOR A PERIOD OF FREEZING RAIN AS WAA STRENGTHENS JUST OFF THE DECK.
THIS SHOULD BE SHORT-LIVED EVENT (IF IT OCCURS AT ALL) AND NOT
WORTHY OF A MENTION IN THE FORECAST. MUCH BIGGER PRECIP TYPE
CHALLENGE ACROSS EASTERN UPPER...WITH STRONG DYNAMICS POSSIBLY
OVERCOMING MARGINAL THERMAL PROFILES TO KEEP PRECIP MAINLY ALL
SNOW...ESPECIALLY ALONG AND NORTH OF M-28. MODEL QPF FIELDS SOMEWHAT
DISCONCERTING...WITH PROGS SUPPORTING A HALF INCH OR MORE OF LIQUID
EQUIVALENT PRECIP BY LATER SATURDAY NIGHT. HEAVIER AMOUNTS NO DOUBT
POSSIBLE GIVEN AMOUNT OF EARLIER MENTIONED DYNAMICS. SNOW RATIOS
WILL NOT BE GREAT...ESPECIALLY SATURDAY AFTERNOON...WHEN SURFACE
READINGS WILL LIKELY EXCEED FREEZING AND HIGH APRIL SUN ANGLE TAKES
HOLD. STILL...COULD EASILY SEE SEVERAL INCHES OF HEAVY WET SNOW
ACCUMULATION BY LATER SATURDAY NIGHT...WITH PERIODS OF HIGH
INTENSITY SNOWFALL. NO HEADLINES FORTHCOMING ON THIS SHIFT...BUT IF
ABOVE COMES TO FRUITION...COULD SEE ADVISORY LEVEL SNOW AMOUNTS FOR
AT LEAST PARTS OF EASTERN UPPER. STAY TUNED! SYSTEM WINDS DOWN
QUICKLY LATE SATURDAY NIGHT...LEAVING BEHIND A DRY SUNDAY AND SUNDAY
EVENING.
CONFIDENCE DROPS REMARKABLY HEADING THROUGH NEXT WORK WEEK...WITH
GUIDANCE STRUGGLING WITH KEY INTERACTIONS TALKED ABOUT IN THE LEAD
PARAGRAPH. PLENTY OF POTENTIAL FOR ADDITIONAL SIGNIFICANT
SYSTEMS...WITH SOME DECENT SUPPORT FOR ONE SUCH SYSTEM TO IMPACT OUR
AREA TO KICK OFF THE WEEK. EXACTLY HOW FAR NORTH THIS SYSTEM RIDES UP
THROUGH THE OHIO VALLEY/SOUTHERN LAKES STILL FAR FROM BEING
DETERMINED. DEPENDING ON SUCH...MAY SEE ENOUGH COLD AIR ALONG THE
NORTHERN PERIPHERY OF ITS PRECIP SHIELD TO SUPPORT SOME WINTRY
WEATHER. NO NEED TO GET TOO SPECIFIC...AND WILL BE FORCED TO RUN
WITH A GUIDANCE CONSENSUS BLEND UNTIL A MORE DETERMINISTIC APPROACH
CAN BE UTILIZED. SAME STORY HEADING THROUGH THE REMAINDER OF THE
WEEK...WITH AGAIN THE POTENTIAL FOR ANOTHER WAVE TO ROTATE NORTHEAST
OUT OF THE SOUTHERN PLAINS. TIMING AND PLACEMENT OF SUCH ALL OVER
THE BOARD...AS IT WILL LIKELY REMAIN WITH BAROCLINIC AXIS SUBJECT TO
MANY CHANGES PER CANADIAN TROUGHING AND PASSAGE OF EARLIER IN THE
WEEK SYSTEMS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 700 PM EDT THU APR 4 2013
OVERALL CONDITIONS WILL REMAIN VFR THRU FRIDAY EVENING AS HIGH
PRESSURE...SUBSIDENCE AND DRY AIR SLOWLY BUILD INTO NRN MICHIGAN.
RESIDUAL LOW CLOUDS BEHIND THE COLD FRONT CURRENTLY TRACKING THRU
NRN LWR MICHIGAN WILL DIMINISH THIS EVENING...EXCEPT FOR LOCATIONS
DOWNWIND OF LAKES SUPERIOR AND MICHIGAN UNDER THE DIRECTION OF
N/NW FLOW. A FEW FLURRIES OR LIGHT LAKE SNOW SHOWERS ARE POSSIBLE
FOR TVC AND MBL TONIGHT...BUT CHANCES ARE LOW AND WILL LEAVE OUT
OF THE TAF FOR NOW. N/NW WINDS BEHIND THE COLD FRONT WILL
PERIODICALLY GUST TO 20 KTS.
&&
.MARINE...
ISSUED AT 344 PM EDT THU APR 4 2013
GUSTY SOUTHWEST WINDS IN ADVANCE OF A FRONTAL BOUNDARY DROPPING
SOUTH OVER NRN MI...WILL TURN NORTHWEST OVERNIGHT AND REMAIN BREEZY
ON THE BACKSIDE OF THE EXITING BOUNDARY. RAIN/SNOW MIXED PCPN WILL
AFFECT NRN MI NEARSHORE WATERS THIS EVENING AS BOUNDARY DROPS
SOUTH...WITH SOME LAKE SNOWS POSSIBLE FRIDAY BEHIND THE FRONT.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...ARNOTT
SYNOPSIS...KAB
SHORT TERM...SWR
LONG TERM...MSB
AVIATION...MR
MARINE...SWR
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
357 AM CDT FRI APR 5 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT FRI APR 5 2013
A MODIFIED ARCTIC FRONT IS LINED UP FROM ROUGHLY KFNB TO KLBF TO
E-KIEN. THE FRONT WILL LIFT NORTH TODAY AS LOW
PRESSURE...CURRENTLY ACROSS NERN WY...MOVES EAST THROUGH SRN SD.
THE TEMPERATURE FCST USES 50 PERCENT OF THE RAP13 AND A BLEND OF
OTHER MODELS. THE RAP IS VERY WARM BUT GIVEN THE CLOUDS MOVING
IN...IT IS PROBABLY TOO WARM.
THE NAM RADAR AND THUNDERSTORM PRODUCTS SUGGEST ISOLATED HIGH
BASED SHRA AND TSTM THIS AFTN AND THIS EVENING. LITTLE OR NO
RAINFALL IS EXPECTED. AS THE SFC LOW TRACKS THROUGH SD TODAY AND
INTO SRN MN TONIGHT...A PACIFIC COLD FRONT WILL DROP THROUGH THE
FCST AREA. THIS WILL KEEP LOWS ON THE WARM SIDE WITH LOWS MAINLY
IN THE 40S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 356 AM CDT FRI APR 5 2013
SATURDAY WILL STILL BE ANOTHER MILD DAY AS MOSTLY SUNNY SKIES
BEHIND THE PACIFIC COLD FRONT PREVAIL. HIGHS SHOULD PUSH IN THE
60S WHICH IS DOWN ABOUT 10 TO 15 DEGREES FROM FRIDAY...BUT STILL
ABOVE NORMAL. SATURDAY NIGHT A TROUGH DEVELOPS ALONG THE FRONT
RANGE AND WILL BRING A SLIGHT CHANCE FOR SHOWERS TO THE EASTERN
PANHANDLE. MOISTURE IS LIMITED AND WILL HAVE TO OVERCOME A DRY
LOWER LAYER THUS EXPECT AMOUNTS LIGHT.
SUNDAY WILL SEE THE NEXT WAVE PUSH ONTO THE HIGH PLAINS. MOISTURE
IS LIMITED WITH PRECIP WATER ONLY AROUND 75 PERCENT OF
NORMAL...FOR APRIL. INSTABILITY INCREASES DURING THE AFTERNOON
WITH HEATING...AND SHOULD BE ENOUGH TO SET OFF SOME THUNDERSTORMS.
CAPE VALUES ONLY A FEW HUNDRED J/KG...HOWEVER GREATER VALUES NOT TO
FAR TO THE SOUTH IN KS.
NEXT WEEK WILL SEE A MAJOR LOW DIG TOWARDS THE 4 CORNERS THEN
EJECT ONTO THE PLAINS BY MID WEEK. THE MODELS CONTINUE TO
STRUGGLE ON TIMING AND STRENGTH OF THE SYSTEM...WHICH LEADS TO A
LOWER THAN AVERAGE CONFIDENCE IN FORECAST.
THE GFS CONTINUES TO BE A FASTER SOLUTION...WHILE THE ECMWF BRINGS
UP THE REAR. INITIALLY THINK AS THE LOW PUSHES TOWARDS THE
ROCKIES...SOME MOISTURE WILL ADVECT NORTH. WE MAY GET DRY SLOTTED
SUNDAY NIGHT INTO MONDAY...AHEAD OF THE LOW. HOWEVER PRECIP WATER
INCREASES TO AROUND AN INCH...WHICH IS CLOSER TO 2 SD...LATE
MONDAY. NEG LI/S SHOULD LEAD TO SOME SHOWERS AND THUNDER ACROSS
MOST OF THE AREA.
THEN AS THE UPPER LOW EJECTS ONTO THE PLAINS...WILL SEE SOME COLD
AIR DEVELOP ON THE BACK SIDE. THIS WILL ALSO WORK IN TANDEM WITH
COOL TEMPS AT NIGHT. WILL NEED TO MENTION SOME SN IN THE NW AND A
MIX TO THE SOUTH AND EAST. LATEST MEX GUIDANCE FOR TUES AND WED
HOLD DAYTIME HIGHS IN THE NW IN THE 30S. WHICH IS POSSIBLE AS THE
CLOUDS WILL LIMIT DIURNAL SWING. ANOTHER CONCERN IS THE TIGHT
PRESSURE GRADIENT...WHICH WILL CREATE SOME WINDY CONDITIONS. THE
SYSTEM IS VERY SLOW TO PUSH ACROSS THE PLAINS...WITH IMPACT
THROUGH AT LEAST EARLY WEDNESDAY.
FOR THE LATER PART OF THE WEEK A SECONDARY UPPER LEVEL DISTURBANCE
ROTATES DOWN ACROSS THE WESTERN PLAINS. ALTHOUGH MODELS HAVE HIGH
PRESSURE AT THE SURFACE...THE UPPER LEVEL WAVE SHOULD HAVE ENOUGH
MOISTURE TO STILL PRODUCE CLOUDS AND SOME LIGHT RAIN OR SNOW.
LONG WAY TROUGH FINALLY SHOULD BE EAST BY THURSDAY OR
FRIDAY...WITH A RIDGE TO THE WEST. THIS WILL RESULT IN NW FLOW AND
A TRAIN OF UPPER LEVEL SHORT WAVES. WILL LIKELY NEED TO MENTION AT
LEAST SOME LIGHT PRECIP TOWARDS THE END OF THE WEEK...HOWEVER
TIMING ISSUES ARE COMMON THIS FAR OUT AND WILL NOT BLANKET POPS.
WILL MONITOR AND ADD WHEN CONFIDENCE IS HIGHER ON LOCATION AND
TIMING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1234 AM CDT FRI APR 5 2013
HIGH LEVEL CLOUDINESS AON 20000 FT AGL WILL BEGIN TO MOVE INTO
WESTERN AND NORTH CENTRAL NEBRASKA OVERNIGHT WITH BROKEN CIGS
EXPECTED FRIDAY MORNING. BROKEN CLOUD COVERAGE WILL PERSIST THROUGH
FRIDAY EVENING. CIGS MAY LOWER TO 12000 TO 15000 FT AGL FRIDAY
EVENING AS A FRONTAL BOUNDARY APPROACHES WESTERN AND NORTH CENTRAL
NEBRASKA. SOUTHERLY WINDS FRIDAY WILL BEGIN TO SHIFT TO THE
SOUTHWEST...THEN WEST FRIDAY EVENING. WIND SPEEDS FRIDAY AND FRIDAY
EVENING WILL RANGE FROM 10 TO 20 KTS WITH SOME GUSTS UP TO 25 KTS
POSSIBLE FRIDAY EVENING.
&&
.FIRE WEATHER...
ISSUED AT 356 AM CDT FRI APR 5 2013
A WEAKNESS IN THE WIND FIELDS IS SHOWING UP ACROSS SWRN NEB.
THUS...RELATIVE HUMIDITY WILL BE VERY LOW IN THAT AREA BUT WINDS
MAY NOT BE STRONG ENOUGH FOR CRITICAL FIRE DANGER. STRONGER WEST
WINDS SHOW UP ACROSS THE ERN NEB PANHANDLE. THESE WEST WINDS WILL
SWEEP EAST THIS AFTN TO NEAR KVTN AND KTIF. SOUTH WINDS CONTINUE
EAST OF HIGHWAY 83. PRESUMABLY...THIS WILL DRAW MORE MOIST AIR
NORTH FROM KS AND OKLAHOMA.
THE RAP MODEL IS VERY DRY AND SUGGESTS CRITICAL FIRE CONDITIONS
COULD SPREAD THROUGHOUT WESTERN AND NORTH CENTRAL NEB THIS
AFTERNOON. THIS IS AN OCCASIONAL BIAS THAT SHOWS IN THE MODEL BUT
IT SENSES THE DRYNESS OF THE ARCTIC AIR AND INCORPORATES IT INTO
THE AFTN WEATHER. THE MODEL COULD BE CORRECT TO A DEGREE. THE
BEST FORECAST IS A BLEND OF THE RAP WHICH IS VERY DRY AND THE
OTHER MODELS WHICH TEND TO BE TOO MOIST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 1 PM CDT /NOON MDT/ THIS AFTERNOON TO 8 PM
CDT /7 PM MDT/ THIS EVENING FOR NEZ204-210.
&&
$$
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...CDC
FIRE WEATHER...CDC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
341 AM CDT FRI APR 5 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 341 AM CDT FRI APR 5 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A SHORTWAVE TROUGH OVER THE PACIFIC NORTHWEST...RIDGING FROM
WEST TEXAS INTO THE NORTHERN PLAINS...AND NORTHERN STREAM TROUGHING
IN THE GREAT LAKES. IN THE WAKE OF THIS TROUGHING...HIGH PRESSURE
HAS BEEN BUILDING IN AT THE SURFACE ACROSS MINNESOTA. 00Z MPX
SOUNDING SHOWED PLENTY OF SUBSIDENCE AND DRY AIR ACCOMPANYING THE
SURFACE HIGH...WITH PRECIPITABLE WATER VALUE AT 0.28 INCHES. AS A
RESULT...SKIES ARE CLEAR ACROSS THE FORECAST AREA. JUST OFF TO THE
WEST...MID AND HIGH LEVEL CLOUDS WERE INCREASING ACROSS THE NORTHERN
PLAINS INTO WESTERN MINNESOTA...WELL DOWNSTREAM OF THE PACIFIC
NORTHWEST SHORTWAVE. THESE CLOUDS ARE ASSOCIATED WITH A WARM
ADVECTION REGIME ON THE TOP OF THE RIDGE...AS WELL AS HELP FROM A
120KT JET STREAK FROM SOUTHERN MANITOBA INTO EASTERN MINNESOTA.
PROFILER AND VAD WIND DATA AT 850MB SHOWED A 30-50 KT SOUTH JET FROM
EASTERN COLORADO INTO THE WESTERN DAKOTAS. ALSO PRESENT AT 850MB WAS
A TIGHT TEMPERATURE GRADIENT...REFLECTED BY 00Z SOUNDINGS OF -6C AT
BISMARCK COMPARED TO +5C AT RAPID CITY AND +10C AT NORTH PLATTE.
DESPITE THE DECENT WARM ADVECTION PATTERN IN PLACE...SURFACE
DEWPOINTS HAVE BEEN SLOW TO RISE. DEWPOINTS WERE ONLY IN THE LOW TO
MID 30S OVER THE CENTRAL PLAINS...WHICH WAS AT LEAST HIGHER THAN IN
THE DAKOTAS WHICH WERE IN THE 20S.
THE FOCUS FOR THE SHORT TERM IS ON TWO PARTS...
1. WARM ADVECTION WELL DOWNSTREAM OF THE PACIFIC NORTHWEST SHORTWAVE
TROUGH
2. EVENTUAL APPROACH OF THE PACIFIC NORTHWEST SHORTWAVE TROUGH
SUBSIDENCE AND DRY AIR ASSOCIATED WITH THE SURFACE HIGH WILL
DOMINATE THIS MORNING. AS WE HEAD INTO THE AFTERNOON...THE UPPER
RIDGE AXIS OVER THE NORTHERN PLAINS IS PROGGED TO SLIDE INTO THE
FORECAST AREA. THUS...AN INCREASE OF THE MID AND HIGH LEVEL CLOUDS
IS LIKELY AS SEEN BACK IN THE DAKOTAS. THE QUESTIONS ARE WILL
PRECIPITATION DEVELOP...AND IF SO WHERE AND WHEN...AS THE WARM
ADVECTION INCREASES THROUGH THE AFTERNOON AND EVENING. THE 05.00Z
GFS/REGIONAL CANADIAN ARE BY FAR THE MOST AGGRESSIVE...DEVELOPING
RAIN ALONG/WEST OF THE MISSISSIPPI RIVER BETWEEN 18-00Z TODAY. THE
05.00Z NAM/05.00Z ECMWF/04.21Z SREF ALSO DEVELOP THE RAIN...BUT KEEP
IT CONFINED NORTHWEST OF THE FORECAST AREA PRIOR TO 00Z. THE LACK OF
MOISTURE CURRENTLY AVAILABLE WOULD SUPPORT THE DRIER SCENARIO...
HOWEVER...850MB MOISTURE TRANSPORT DOES INTENSIFY THROUGH THE DAY
AND BY 00Z IS POINTING ON THE WEST SIDE OF THE FORECAST AREA.
THUS...FELT AT LEAST KEEPING SOME 20-50 PERCENT CHANCES LATE IN THE
DAY ARE APPROPRIATE OVER THE WESTERN PORTIONS OF THE FORECAST
AREA...HIGHEST FROM WABASHA INTO DODGE COUNTIES.
FOR TONIGHT...MODELS PROG THE PACIFIC NORTHWEST SHORTWAVE TROUGH TO
ENTER WESTERN SOUTH DAKOTA...CAUSING A SURFACE LOW TO FORM AND
DEEPEN OVER SOUTHERN SOUTH DAKOTA. PERSISTENT AND INTENSIFYING WARM
ADVECTION AHEAD OF THIS SHORTWAVE TROUGH AND SURFACE LOW LOOKS TO
EXPAND THE AREA OF PRECIPITATION OVER MOST LOCATIONS EAST OF THE
MISSISSIPPI RIVER IN THE EVENING...WHICH THEN LIFTS NORTHEAST AFTER
MIDNIGHT. EVAPORATIVE COOLING MAY CAUSE THE PRECIPITATION TO SWITCH
FROM RAIN TO SNOW IN THE EVENING NORTHEAST OF I-94...BUT EVENTUALLY
WARMER AIR ADVECTS IN THERE AFTER MIDNIGHT ALOFT AND THEN SURFACE
TO CAUSE A CHANGE-OVER TO SLEET AND RAIN. IF TEMPERATURES CAN HOLD
BELOW FREEZING...A VERY BRIEF PERIOD OF FREEZING RAIN WOULD OCCUR.
MODEL CONSENSUS CONTINUES TO FAVOR ALONG/NORTHEAST OF I-94 TO HAVE
THE BULK OF THE PRECIPITATION...THUS PRECIPITATION CHANCES NEAR 100
SEEMS REASONABLE. REGARDING SNOWFALL ACCUMULATION...GIVEN THE
GENERAL WARM SENSE TO THIS WARM ADVECTION EVENT...NOTED BY 850MB
TEMPS THAT ARE ONLY -2 TO -4C WHEN IT IS SNOWING...SNOW TO WATER
RATIOS SHOULD ONLY MAX OUT AROUND 10 TO 1. WITH UPWARDS OF 0.1-0.3
INCHES OF QPF PROGGED...SNOW TOTALS COULD BE AS MUCH AS 3
INCHES...THOUGH THE MAJORITY SHOULD END UP IN THE 1 TO 2 INCH
RANGE...NOT ENOUGH FOR AN ADVISORY AT THIS POINT. COULD USE THE MIX
PRECIPITATION AS A NEED FOR THE ADVISORY...BUT CONFIDENCE ON THE
AMOUNT OF MIXED PRECIPITATION IS TOO LOW TO WARRANT ONE.
TEMPERATURES TODAY WILL END UP COOLER COMPARED TO YESTERDAY DUE TO
INCREASING CLOUDS AS WELL AS 850MB TEMPS BETWEEN -2 AND -6C AT 18Z.
FOR TONIGHT...INCREASING SOUTHERLY WINDS PLUS CLOUDS SHOULD HELP
KEEP TEMPERATURES UP AT OR ABOVE FREEZING. IN FACT...EXPECTING
TEMPERATURES TO CLIMB LATE IN THE NIGHT AS THE SURFACE WARM FRONT
LIFTS NORTH TOWARDS I-94.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 341 AM CDT FRI APR 5 2013
HIGHLIGHTS:
1. CURRENT PACIFIC NORTHWEST SHORTWAVE TROUGH PROGGED TO MOVE
THROUGH THE AREA ON SATURDAY
2. POTENTIAL FOR AN ACTIVE BUT HARD TO TIME PRECIPITATION PATTERN
SUNDAY NIGHT AND BEYOND.
MODELS ARE IN REALLY GOOD AGREEMENT TRACKING THE SHORTWAVE TROUGH
THAT WAS OVER SOUTH DAKOTA LATE TONIGHT INTO AND POSSIBLY THROUGH
THE FORECAST AREA ON SATURDAY. STRONG DYNAMIC FORCING WITH THIS
SHORTWAVE...NOTED SIMPLY BY 60-90 METER HEIGHT FALLS IN 12 HOURS AT
500MB...ALONG WITH THAT SURGE OF 850MB MOISTURE TRANSPORT AHEAD OF
THE SHORTWAVE PROVIDING MOISTURE SHOULD HELP PRODUCE RAIN ACROSS
MOST OF THE FORECAST AREA. THE ONLY MODEL NOT SHOWING THIS IS THE
05.00Z NAM...AT LEAST SOUTH OF I-90...WHICH SEEMS ODD GIVEN THE
FORCING. THE 05.00Z REGIONAL CANADIAN IS ACTUALLY QUITE ROBUST SOUTH
OF I-90 WITH QPF AMOUNTS OF 0.1-0.25 INCHES WITH A FEW ISOLATED 0.5
INCH AMOUNTS FROM VERNON INTO ADAMS COUNTIES. IT APPEARS THE HEAVIER
QPF IS A RESULT OF CONVECTIVE ELEMENTS FORMING AHEAD OF THE
SHORTWAVES ASSOCIATED COLD FRONT AT THE SURFACE. INSTABILITY IS
FAIRLY MEAGER DUE TO CAPPING AROUND 750MB AND LIMITED MOISTURE.
HOWEVER...THERE IS A ZONE OF NEGATIVE EPV DUE TO UPRIGHT INSTABILITY
IN CROSS-SECTIONS AROUND 700MB...THUS A FEW THUNDERSTORMS CANNOT BE
RULED OUT. PRECIPITATION SHOULD SHIFT OFF TO THE EAST PRETTY QUICK
LATE IN THE AFTERNOON INTO THE EARLY EVENING FOR MOST OF THE
AREA...AS STRONG SUBSIDENCE COMES IN BEHIND THE SHORTWAVE TROUGH.
ONLY PLACE THIS MAY NOT OCCUR AS FAST IS NORTH AND EAST OF
I-94...DUE TO THE SUGGESTION OF A SHORTWAVE COMING IN BEHIND THE
SHORTWAVE TROUGH AND A MID-LEVEL FRONTOGENESIS ZONE DROPPING
SOUTHEAST. TEMPERATURES MAY COOL ENOUGH TO ALLOW FOR SOME SNOW OUT
OF THIS PRECIPITATION BEFORE IT ENDS BY MIDNIGHT. VERY LITTLE
ACCUMULATION ANTICIPATED...THOUGH.
A MAJOR PATTERN CHANGE IS FORECAST TO TAKE PLACE SUNDAY AS A POTENT
SHORTWAVE TROUGH IMPACTS AND DIGS INTO THE PACIFIC NORTHWEST.
HEADING INTO THE EARLY PORTION OF THE WORK WEEK...MODELS ARE IN GOOD
AGREEMENT DIGGING THIS TROUGH SOUTH INTO THE FOUR CORNERS REGION...
SETTING UP A SOUTHWEST FLOW PATTERN INTO THE FORECAST AREA. THIS
MEANS HARD TO TIME SHORTWAVES AND THUS PLENTY OF UNCERTAINTY. TAKE
FOR EXAMPLE SUNDAY NIGHT WHERE THE 05.00Z ECMWF/NAM BRING A
SHORTWAVE THROUGH THE AREA WITH WIDESPREAD QPF. THE 05.00Z CANADIAN
IS EVEN MORE POTENT WITH THIS SHORTWAVE AND A BIT FARTHER SOUTHEAST.
ON THE OTHER HAND...THE 05.00Z GFS DOES NOT SHOW THE SHORTWAVE AT
ALL...THUS RESULTING IN A DRY FORECAST. MAJORITY HERE SUGGESTS AT
LEAST 30-50 PERCENT PRECIPITATION CHANCES ARE NEEDED. MOST OF THE
PRECIPITATION SHOULD FALL AS RAIN...BUT COULD MIX WITH SNOW
ALONG/NORTHEAST OF I-94.
THE MOST INTERESTING TIME PERIOD OF NEXT WEEK IS TUESDAY INTO
WEDNESDAY...AS THE UPPER TROUGH IN THE SOUTHWEST U.S. EJECTS OUT.
THERE REMAINS A WHOLE LOT OF UNCERTAINTY ON THE TIMING AND DETAILS
OF THIS EJECTION. HOWEVER...EVERY MODEL AVAILABLE AT THIS POINT HAS
SOME SYSTEM AFFECTING THE AREA. WE COULD END UP SEEING CONVECTION IN
THE GFS SCENARIO...POTENTIAL FOR MODERATE TO HEAVY RAINFALL IN ANY
MODEL...AND EVEN SOME SNOW ON THE BACK SIDE OF THE SYSTEM ONCE THE
UPPER TROUGH MOVES OVERHEAD. WE WILL HAVE TO KEEP A WATCH ON THIS
PERIOD. GIVEN THE CONSENSUS AGREEMENT FOR PRECIPITATION TUESDAY INTO
TUESDAY NIGHT...RAISED PRECIPITATION CHANCES DURING THIS PERIOD. MAY
NEED TO RAISE CHANCES FOR WEDNESDAY AS WELL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1100 PM CDT THU APR 4 2013
HIGH PRESSURE WILL SETTLE ACROSS THE UPPER MISSISSIPPI RIVER VALLEY
OVERNIGHT...WITH VFR SKC CONDITIONS AND GENERALLY LIGHT/VRB
WINDS. HIGH/MID LEVEL CLOUDS WILL BE ON THE INCREASE FRIDAY
AFTERNOON...AHEAD OF AN APPROACHING NORTHERN PLAINS SHORTWAVE
TROUGH. WINDS WILL INCREASE AND BECOME SOUTHERLY BEHIND THE
DEPARTING HIGH. VFR WILL CONTINUE.
FRIDAY NIGHT/SAT POSES SOME DIFFICULTIES FOR CIGS AND RAIN
POTENTIAL. OVERALL...THE NAM/GFS/EC FAVOR KEEPING THE DEEPER
SATURATION AND PCPN CHANCES JUST NORTH OF KRST/KLSE. HOWEVER...SOME
SIGNS THAT THE MOISTURE COULD BE A BIT FARTHER SOUTH...BRINGING A
THREAT FOR MVFR CIGS. ALSO...A GOOD SLUG OF 925-850 MB WARM AIR
ADVECTION/MOISTURE TRANSPORT...WHICH COULD RESULT IN SOME PCPN
CHANCES. THINK THE BEST CHANCES WILL COME WITH THE SYSTEM/S COLD
FRONT...WHICH MOVES EAST ACROSS THE REGION LATE SAT
MORNING/AFTERNOON. THAT SAID...ENOUGH FORCING FRI EVENING TO ADD
-SHRA TO THE TAFS.
&&
.HYDROLOGY...
ISSUED AT 341 AM CDT FRI APR 5 2013
RIVER STATUS...
HYDROGRAPHS ACROSS THE AREA SHOW TRIBUTARY RIVERS AND STREAMS INTO
THE MISSISSIPPI RUNNING WITHIN BANK FLOWS WITH A FEW HIGHER THAN
NORMAL GIVEN THE SNOW MELT. MOST OF THE HIGH RIVER FLOWS ARE
CONFINED TO RIVERS NORTH OF I-90 WHERE SNOW PACK STILL EXISTS. THE
WHITEWATER...TREMPEALEAU AND BLACK RIVERS ARE OF CONCERN AT THE
MOMENT.
SNOW PACK...
LATEST NOHRSC DATA SHOWED SNOW WATER EQUIVALENTS STILL IN THE 1-2
INCH RANGE OVER WINONA...BUFFALO...TREMPEALEAU AND JACKSON
COUNTIES...WHILE 2-3 INCH AMOUNTS WERE PRESENT IN CLARK AND TAYLOR
COUNTIES.
RAINFALL...
THE SYSTEM COMING IN FOR TONIGHT AND SATURDAY NOW LOOKS TO NOT
PRODUCE AS MUCH RAINFALL AS PREVIOUSLY EXPECTED...MOSTLY LESS THAN
1/3 OF AN INCH SOUTHWEST OF I-94 TO 1/3 TO 1/2 INCH NORTH OF I-94.
NOTE THAT SOME SNOW IS FORECAST TONIGHT NORTH AND EAST OF
I-94...WHICH COULD TOTAL UP TO 0.3 OF LIQUID EQUIVALENT. ADDITIONAL
RAINFALL IS POSSIBLE SUNDAY NIGHT WITH POTENTIAL FOR MODERATE TO
HEAVY RAINFALL TUESDAY INTO WEDNESDAY OF NEXT WEEK.
TEMPERATURES...
A COOLER DAY BUT STILL PLENTY WARM ENOUGH FOR SNOW MELT IS EXPECTED
TODAY AS HIGHS CLIMB INTO THE 40S. PROBLEM TONIGHT IS THAT
TEMPERATURES MAY NOT FALL BELOW FREEZING AND WITH WARMER CONDITIONS
ANTICIPATED ON SATURDAY...WE COULD REALLY SEE SOME SNOW MELT. MOST
OF THE NEXT 7 DAYS LOOK TO HAVE DAYTIME TEMPERATURES AT LEAST
40...THUS FAVORABLE CONDITIONS ARE IN PLACE FOR SNOW MELT EVERY DAY.
FROST DEPTH...
FROST REMAINS FAIRLY DEEP IN THE GROUND STILL. AS OF 7 AM APRIL
4TH...CUBA CITY WI WAS AT 16 INCHES...WHITEHALL WAS AT 19
INCHES...AND BLOOMER IN CHIPPEWA COUNTY WAS AT 38 INCHES.
SUMMARY...
NOW THAT LESS RAINFALL IS FORECAST THAN EXPECTED FOR TONIGHT AND
SATURDAY...ANY FLOODING CONCERN WOULD COME MOSTLY FROM SNOW MELT THE
NEXT FEW DAYS. CERTAINLY ANY RIVERS AND STREAMS FROM WINONA AND
WABASHA COUNTIES INTO BUFFALO TREMPEALEAU...JACKSON...CLARK AND
TAYLOR WOULD BE OF CONCERN. HAVE DECIDED TO KEEP THE ESF GOING
AND EXPANDED IT INTO WINONA COUNTY GIVEN THE ISSUES BEING
EXPERIENCED ON THE WHITEWATER RIVER. CONSIDERED ISSUING A FLOOD
WATCH FOR JUST RIVERS...BUT GIVEN THAT LESS RAINFALL IS EXPECTED
AND WE ALREADY HAVE EXPERIENCED RIVERS IN AND OUT OF MINOR FLOOD
STAGE THE LAST FEW DAYS...FEEL THE ESF IS STILL VALID. MAY STILL
NEED A FLOOD WATCH...THOUGH...AS CERTAINTY INCREASES ABOUT THE
AMOUNT OF SNOW MELT THIS WEEKEND. EITHER WAY...DEFINITELY NEED TO
KEEP AN EYE ON TUESDAY INTO WEDNESDAY OF NEXT WEEK.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS MIAMI FL
953 AM EDT FRI APR 5 2013
.UPDATE...
CURRENT WAVE OF PRECIPITATION THIS MORNING ACROSS LAKE OKEECHOBEE
TO SOUTHWEST FLORIDA, THEN DOWN INTO THE SE GULF OF MEXICO MAKING
STEADY EASTWARD PROGRESS AHEAD OF THE POWERFUL SHORTWAVE TROUGH OVER
THE EASTERN GULF OF MEXICO. ATMOSPHERE HAS STABILIZED IN THE LOW
LEVELS IN THE WAKE OF THE OVERNIGHT AND EARLY MORNING CONVECTION,
WHICH IS ACTING TO LIMIT THE INTENSITY OF THE ACTIVITY CURRENTLY
MOVING OVER THE AREA. SOUTHERLY FLOW TRYING TO DESTABILIZE THE
LOW LEVELS THIS MORNING, BUT OVERCAST CLOUD SHIELD WILL MITIGATE
ANY SIGNIFICANT WARMING AND SPC HAS APPROPRIATELY DOWNPLAYED THE
SEVERE THREAT ACROSS SOUTH FLORIDA TODAY.
FORECAST UPDATE HAS NUMEROUS SHOWERS AND ISOLATED TSTMS,
GRADUALLY TAPERING OFF FROM NW TO SE AS THE COLD FRONT CURRENTLY
APPROACHING THE TAMPA BAY REGION MOVES INTO THE AREA THIS
AFTERNOON. LOWERED TEMPERATURES A FEW DEGREES DUE TO COOLER
READINGS THIS MORNING AND EXTENSIVE CLOUD COVER.
INTERESTING TIDBIT: A "WAKE LOW" FEATURE WAS NOTED EARLY THIS
MORNING OVER PARTS OF SOUTH FLORIDA WHICH HELPED TO PRODUCE NON-
THUNDERSTORM WIND GUSTS OF 35 TO 45 MPH IN THE NAPLES AREA AS WELL
AS LAKE OKEECHOBEE AND PARTS OF THE PALM BEACHES. THIS IS THE SAME
TYPE OF FEATURE WHICH PRODUCED THE STRONG WINDS IN THE MOBILE AREA
BACK ON WEDNESDAY, AND THIS HAS BEEN NOTED IN PAST SPRINGTIME
CONVECTION EVENTS OVER SOUTH FLORIDA AND OTHER PARTS OF THE
SOUTHERN UNITED STATES. /MOLLEDA
&&
.PREV DISCUSSION... /ISSUED 831 AM EDT FRI APR 5 2013/
AVIATION...
A BAND OF LIGHT RAIN WILL MOVE ACROSS SOUTH FLORIDA INTO EARLY
THIS AFTERNOON WITH SOME MVFR CIGS/VISIBILITIES BUT MOSTLY VFR. IT
IS POSSIBLE DEPENDING ON ANY BREAKS IN THE CLOUD COVER THAT A FEW
THUNDERSTORMS COULD ALSO DEVELOP BY EARLY THIS AFTERNOON AHEAD OF
THE FRONT. THESE CONDITIONS WILL DIMINISH THIS AFTERNOON AS THE
COLD FRONT CLEARS THE PENINSULA. SURFACE WIND WILL BE SSW TO SW
INCREASING IN SPEEDS AND OCCASIONALLY GUSTING OVER 20KT AFT 13-14Z
SHIFTING TO THE NORTHWEST BEHIND THE FRONT.
KOB
PREV DISCUSSION... /ISSUED 343 AM EDT FRI APR 5 2013/
DISCUSSION...
AN MCS WAS MOVING ACROSS THE EASTERN GULF AND SOUTH FLORIDA EARLY
THIS MORNING. AN UPPER LEVEL LOW WAS MOVING EAST ACROSS
ALABAMA...WITH BROAD SURFACE LOW PRESSURE AREAS FROM NORTHERN
FLORIDA NORTHWARD TO OFF THE COAST OF NORTH CAROLINA. GLOBAL
MODELS ARE NOT HANDLING THE CURRENT SITUATION WELL...SO FOLLOWED
CLOSER TO THE HRRR OUTPUT THROUGH THE AFTERNOON.
THE ATMOSPHERE OVER SOUTH FLORIDA IS EXPECTED TO BECOME WORKED
OVER FROM THIS MCS...WITH MUCH MORE STABLE CONDITIONS. CLOUD
COVER WILL BLANKET THE REGION FOR MUCH OF THE DAY. SO THE SEVERE
THREAT APPEARS TO HAVE DIMINISHED...WITH THE LAST STRONG STORMS
ACROSS THE FAR SOUTHEASTERN PORTIONS OF MIAMI DADE COUNTY EARLY
THIS MORNING. SO LIGHT/MODERATE RAIN WITH A FEW EMBEDDED
THUNDERSTORMS ARE ALL THAT IS EXPECTED THROUGH THE MID/LATE
AFTERNOON...BEFORE THE COLD FRONT PUSHES THROUGH THE REGION.
UNDERCUT MAV/MET TEMPERATURES AT MOST LOCATIONS TODAY DUE TO THE
EXPECTED CLOUD COVER AND RAIN.
A FEW LINGERING SHOWERS ARE POSSIBLE INTO THE EARLY EVENING.
OTHERWISE...DRIER AND COOLER CONDITIONS ARE EXPECTED OVER SOUTH
FLORIDA TONIGHT. THE WEEKEND LOOKS LIKE IT WILL BE A PLEASANT
ONE WITH TEMPERATURES NEAR NORMAL FOR EARLY APRIL. A LIGHT TO
MODERATE NORTHEASTERLY FLOW WILL PREVAIL ON SATURDAY...WITH WINDS
SHIFTING TO THE EAST ON SUNDAY AS HIGH PRESSURE MOVES INTO THE
WESTERN ATLANTIC OFF THE EASTERN CONUS.
HIGH PRESSURE WILL REMAIN OVER THE WESTERN ATLANTIC THROUGH THE
MIDDLE OF THE WEEK...WITH LOW LEVEL MOISTURE RETURNING TO THE
REGION. HIGHS WILL REMAIN IN THE LOW 80S EAST TO THE MID TO UPPER
80S TOWARD THE GULF COAST. OVERNIGHT LOW TEMPERATURES WILL
INCREASE TO THE LOWER 70S FOR THE EAST COAST METRO AREAS. A FEW
STREAMER SHOWERS WILL BE POSSIBLE EACH DAY FROM TUESDAY THROUGH
THE END OF THE WEEK.
AVIATION...06Z TAFS.
MATURE MCS MOVING ACROSS THE EASTERN GULF AND
ACROSS SOUTH FLORIDA EARLY THIS MORNING. STRONG TO SEVERE STORMS
ARE POSSIBLE AT KFXE SOUTHWARD ON THE EAST COAST OVER THE NEXT FEW
HOURS. PREVAILING MVFR CONDITIONS ARE EXPECTED FOR MOST OF THE
EAST COAST TAF SITES THROUGH THE OVERNIGHT HOURS...WITH IFR
CONDITIONS POSSIBLE IN THUNDERSTORMS. KAPF IS IN THE RAIN SHIELD
ON THE NORTH SIDE OF THE MCS...AND LIGHT/MODERATE RAIN WITH A FEW
HIGH BASED LIGHTNING STRIKES WILL CONTINUE THROUGH THE MORNING
HOURS. LIGHT/MODERATE RAIN IS EXPECTED AFTER 10-12Z ACROSS THE
REGION AS THE MCS MOVES THROUGH AND SOUTH FLORIDA GETS WORKED
OVER. AT THIS TIME IS IT DIFFICULT TO SAY WHETHER THERE WILL BE
ANY REGENERATION OF THUNDERSTORMS BY THE AFTERNOON HOURS DUE TO
ALL THE CLOUD COVER. BASED OFF OF LATEST GUIDANCE...WILL ONLY SHOW
RAIN AFTER 12-14Z...WITH CONDITIONS IMPROVING BY MID/LATE
AFTERNOON. THE FRONT IS EXPECTED TO PASS THROUGH THE REGION
18-21Z...WITH LIGHT/MODERATE NORTHWESTERLY FLOW THROUGH THE END OF
THE TAF PERIOD.
MARINE...
LATEST GUIDANCE INDICATES THAT WINDS ACROSS THE LOCAL GULF AND
ATLANTIC WATERS COULD REACH AROUND 20 KNOTS THIS MORNING AND SEAS
ACROSS THE OFF SHORE GULF WATERS COULD REACH NEAR 7 FEET. A SMALL
CRAFT ADVISORY IS IN EFFECT THROUGH 00Z THIS EVENING FOR ALL OF
THE LOCAL WATERS. A COLD FRONT WILL MOVE THROUGH THE REGION LATE
THIS AFTERNOON...WITH WINDS SHIFTING TO THE NORTHWEST BEHIND THE
FRONT. NORTHEAST WINDS 15-20 KNOTS ARE EXPECTED ON SATURDAY...WITH
EASTERLY WINDS 10-15 KNOTS ON SUNDAY. EAST TO SOUTHEAST WINDS ARE
THEN EXPECTED THROUGH THE WEEK AS HIGH PRESSURE BUILDS ACROSS THE
WESTERN ATLANTIC.
FIRE WEATHER...
MUCH NEEDED RAINFALL WILL CONTINUE TO FALL ACROSS MUCH OF THE
REGION THROUGH THE DAY TODAY. A FEW EMBEDDED THUNDERSTORMS ARE
POSSIBLE INTO THE AFTERNOON. A COLD FRONT WILL MOVE THROUGH THE
REGION LATE THIS AFTERNOON INTO THIS EVENING...WITH DRIER AND
COOLER CONDITIONS EXPECTED TONIGHT. MINIMUM RELATIVE HUMIDITY
VALUES AND SATURDAY ARE EXPECTED TO REMAIN JUST ABOVE CRITICAL
VALUES ACROSS THE INTERIOR WEST. HIGH PRESSURE WILL THEN BUILD
ACROSS THE WESTERN ATLANTIC SUNDAY THROUGH THE MIDDLE OF THE
WEEK...WITH LOW LEVEL MOISTURE RETURNING TO SOUTH FLORIDA.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 77 61 77 67 / 70 10 0 -
FORT LAUDERDALE 78 65 79 69 / 70 10 0 -
MIAMI 77 64 79 68 / 70 20 0 -
NAPLES 73 58 81 62 / 70 10 0 -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR BISCAYNE
BAY-COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL
OUT 20 NM-COASTAL WATERS FROM JUPITER INLET TO DEERFIELD
BEACH, FL OUT 20 NM-LAKE OKEECHOBEE-WATERS FROM DEERFIELD
BEACH TO OCEAN REEF, FL EXTENDING FROM 20 NM TO THE
TERRITORIAL WATERS OF THE BAHAMAS-WATERS FROM JUPITER INLET
TO DEERFIELD BEACH, FL EXTENDING FROM 20 NM TO 60 NM.
GM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR COASTAL
WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT
20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL
EXTENDING FROM 20 TO 60 NM.
&&
$$
PUBLIC/MARINE...59/MOLLEDA
AVIATION/RADAR/FIRE...30/KOB
AREA FORECAST DISCUSSION
NWS MIAMI FL
831 AM EDT FRI APR 5 2013
.AVIATION...
A BAND OF LIGHT RAIN WILL MOVE ACROSS SOUTH FLORIDA INTO EARLY
THIS AFTERNOON WITH SOME MVFR CIGS/VISIBILITIES BUT MOSTLY VFR. IT
IS POSSIBLE DEPENDING ON ANY BREAKS IN THE CLOUD COVER THAT A FEW
THUNDERSTORMS COULD ALSO DEVELOP BY EARLY THIS AFTERNOON AHEAD OF
THE FRONT. THESE CONDITIONS WILL DIMINISH THIS AFTERNOON AS THE
COLD FRONT CLEARS THE PENINSULA. SURFACE WIND WILL BE SSW TO SW
INCREASING IN SPEEDS AND OCCASIONALLY GUSTING OVER 20KT AFT 13-14Z
SHIFTING TO THE NORTHWEST BEHIND THE FRONT.
KOB
&&
.PREV DISCUSSION... /ISSUED 343 AM EDT FRI APR 5 2013/
DISCUSSION...
AN MCS WAS MOVING ACROSS THE EASTERN GULF AND SOUTH FLORIDA EARLY
THIS MORNING. AN UPPER LEVEL LOW WAS MOVING EAST ACROSS
ALABAMA...WITH BROAD SURFACE LOW PRESSURE AREAS FROM NORTHERN
FLORIDA NORTHWARD TO OFF THE COAST OF NORTH CAROLINA. GLOBAL
MODELS ARE NOT HANDLING THE CURRENT SITUATION WELL...SO FOLLOWED
CLOSER TO THE HRRR OUTPUT THROUGH THE AFTERNOON.
THE ATMOSPHERE OVER SOUTH FLORIDA IS EXPECTED TO BECOME WORKED
OVER FROM THIS MCS...WITH MUCH MORE STABLE CONDITIONS. CLOUD
COVER WILL BLANKET THE REGION FOR MUCH OF THE DAY. SO THE SEVERE
THREAT APPEARS TO HAVE DIMINISHED...WITH THE LAST STRONG STORMS
ACROSS THE FAR SOUTHEASTERN PORTIONS OF MIAMI DADE COUNTY EARLY
THIS MORNING. SO LIGHT/MODERATE RAIN WITH A FEW EMBEDDED
THUNDERSTORMS ARE ALL THAT IS EXPECTED THROUGH THE MID/LATE
AFTERNOON...BEFORE THE COLD FRONT PUSHES THROUGH THE REGION.
UNDERCUT MAV/MET TEMPERATURES AT MOST LOCATIONS TODAY DUE TO THE
EXPECTED CLOUD COVER AND RAIN.
A FEW LINGERING SHOWERS ARE POSSIBLE INTO THE EARLY EVENING.
OTHERWISE...DRIER AND COOLER CONDITIONS ARE EXPECTED OVER SOUTH
FLORIDA TONIGHT. THE WEEKEND LOOKS LIKE IT WILL BE A PLEASANT
ONE WITH TEMPERATURES NEAR NORMAL FOR EARLY APRIL. A LIGHT TO
MODERATE NORTHEASTERLY FLOW WILL PREVAIL ON SATURDAY...WITH WINDS
SHIFTING TO THE EAST ON SUNDAY AS HIGH PRESSURE MOVES INTO THE
WESTERN ATLANTIC OFF THE EASTERN CONUS.
HIGH PRESSURE WILL REMAIN OVER THE WESTERN ATLANTIC THROUGH THE
MIDDLE OF THE WEEK...WITH LOW LEVEL MOISTURE RETURNING TO THE
REGION. HIGHS WILL REMAIN IN THE LOW 80S EAST TO THE MID TO UPPER
80S TOWARD THE GULF COAST. OVERNIGHT LOW TEMPERATURES WILL
INCREASE TO THE LOWER 70S FOR THE EAST COAST METRO AREAS. A FEW
STREAMER SHOWERS WILL BE POSSIBLE EACH DAY FROM TUESDAY THROUGH
THE END OF THE WEEK.
AVIATION...06Z TAFS.
MATURE MCS MOVING ACROSS THE EASTERN GULF AND
ACROSS SOUTH FLORIDA EARLY THIS MORNING. STRONG TO SEVERE STORMS
ARE POSSIBLE AT KFXE SOUTHWARD ON THE EAST COAST OVER THE NEXT FEW
HOURS. PREVAILING MVFR CONDITIONS ARE EXPECTED FOR MOST OF THE
EAST COAST TAF SITES THROUGH THE OVERNIGHT HOURS...WITH IFR
CONDITIONS POSSIBLE IN THUNDERSTORMS. KAPF IS IN THE RAIN SHIELD
ON THE NORTH SIDE OF THE MCS...AND LIGHT/MODERATE RAIN WITH A FEW
HIGH BASED LIGHTNING STRIKES WILL CONTINUE THROUGH THE MORNING
HOURS. LIGHT/MODERATE RAIN IS EXPECTED AFTER 10-12Z ACROSS THE
REGION AS THE MCS MOVES THROUGH AND SOUTH FLORIDA GETS WORKED
OVER. AT THIS TIME IS IT DIFFICULT TO SAY WHETHER THERE WILL BE
ANY REGENERATION OF THUNDERSTORMS BY THE AFTERNOON HOURS DUE TO
ALL THE CLOUD COVER. BASED OFF OF LATEST GUIDANCE...WILL ONLY SHOW
RAIN AFTER 12-14Z...WITH CONDITIONS IMPROVING BY MID/LATE
AFTERNOON. THE FRONT IS EXPECTED TO PASS THROUGH THE REGION
18-21Z...WITH LIGHT/MODERATE NORTHWESTERLY FLOW THROUGH THE END OF
THE TAF PERIOD.
MARINE...
LATEST GUIDANCE INDICATES THAT WINDS ACROSS THE LOCAL GULF AND
ATLANTIC WATERS COULD REACH AROUND 20 KNOTS THIS MORNING AND SEAS
ACROSS THE OFF SHORE GULF WATERS COULD REACH NEAR 7 FEET. A SMALL
CRAFT ADVISORY IS IN EFFECT THROUGH 00Z THIS EVENING FOR ALL OF
THE LOCAL WATERS. A COLD FRONT WILL MOVE THROUGH THE REGION LATE
THIS AFTERNOON...WITH WINDS SHIFTING TO THE NORTHWEST BEHIND THE
FRONT. NORTHEAST WINDS 15-20 KNOTS ARE EXPECTED ON SATURDAY...WITH
EASTERLY WINDS 10-15 KNOTS ON SUNDAY. EAST TO SOUTHEAST WINDS ARE
THEN EXPECTED THROUGH THE WEEK AS HIGH PRESSURE BUILDS ACROSS THE
WESTERN ATLANTIC.
FIRE WEATHER...
MUCH NEEDED RAINFALL WILL CONTINUE TO FALL ACROSS MUCH OF THE
REGION THROUGH THE DAY TODAY. A FEW EMBEDDED THUNDERSTORMS ARE
POSSIBLE INTO THE AFTERNOON. A COLD FRONT WILL MOVE THROUGH THE
REGION LATE THIS AFTERNOON INTO THIS EVENING...WITH DRIER AND
COOLER CONDITIONS EXPECTED TONIGHT. MINIMUM RELATIVE HUMIDITY
VALUES AND SATURDAY ARE EXPECTED TO REMAIN JUST ABOVE CRITICAL
VALUES ACROSS THE INTERIOR WEST. HIGH PRESSURE WILL THEN BUILD
ACROSS THE WESTERN ATLANTIC SUNDAY THROUGH THE MIDDLE OF THE
WEEK...WITH LOW LEVEL MOISTURE RETURNING TO SOUTH FLORIDA.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 79 61 77 67 / 60 10 0 -
FORT LAUDERDALE 78 65 79 69 / 70 10 0 -
MIAMI 78 64 79 68 / 70 20 0 -
NAPLES 75 58 81 62 / 50 10 0 -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR BISCAYNE
BAY-COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL
OUT 20 NM-COASTAL WATERS FROM JUPITER INLET TO DEERFIELD
BEACH, FL OUT 20 NM-LAKE OKEECHOBEE-WATERS FROM DEERFIELD
BEACH TO OCEAN REEF, FL EXTENDING FROM 20 NM TO THE
TERRITORIAL WATERS OF THE BAHAMAS-WATERS FROM JUPITER INLET
TO DEERFIELD BEACH, FL EXTENDING FROM 20 NM TO 60 NM.
GM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR COASTAL
WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT
20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL
EXTENDING FROM 20 TO 60 NM.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
732 AM EDT FRI APR 5 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 622 AM EDT FRI APR 5 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CONFLUENT NW FLOW
ALF OVER THE GRT LKS DOWNSTREAM OF RDG OVER THE ROCKIES. AT THE
LLVLS...THE CWA IS DOMINATING BY A NW FLOW OF COLDER AIR IN THE WAKE
OF THU COLD FROPA AND AHEAD OF SFC HI PRES NEAR LK WINNIPEG. SINCE
THE 00Z INL RAOB SHOWED A VERY DRY...INVERTED V PROFILE AND RECENT
SFC OBS INDICATE FAIRLY LARGE SFC T/TD SPREADS...SKIES ARE MOCLR
OVER UPR MI AS OF 06Z. BUT THE 00Z YPL RAOB DEPICTED A SOMEWHAT
MOISTER...BUT STILL WELL MIXED...SFC-H85 T/TD PROFILE WITH AN H85
TEMP DOWN TO -16C. FARTHER UPSTREAM...A SHRTWV IS MOVING INTO THE
PAC NW. WAD MID/HI CLDS WELL E OF THIS DISTURBANCE ARE SPREADING
INTO THE NRN PLAINS.
TODAY...ALTHOUGH SKIES ARE MOCLR EARLY THIS MRNG...SUSPECT SOME LK
CLDS/EVEN SOME -SHSN MIGHT DVLP OVER AREAS E OF MQT AS THE
MOISTER...COLDER AIRMASS SHOWN ON THE 00Z YPL RAOB WITH H85 TEMPS AS
LO AS -15C IMPACT THIS PART OF THE CWA. OVER THE W HALF...THE VERY
DRY 00Z INL RAOB IS MORE REPRESENTATIVE OF THE SOURCE AIRMASS. SO
REMOVED POPS/DIMINISHED FCST CLDS IN THIS AREA. BUT EVEN OVER THE
E...GENERALY ACYC NATURE OF THE FCST LLVL FLOW AS WELL AS HIER SFC
T/TD DEPRESSIONS EVEN FARTHER E N OF LK SUP SUG ANY SN ACCUMS WL BE
NEGLIGIBLE IF SHSN DO FORM AT ALL. WITH DAYTIME HEATING/LARGE SCALE
SUBSIDENCE AS SFC HI BLDS OVER THE W HALF OF THE CWA BY 18Z...EXPECT
ANY LES OVER THE E TO DIMINISH BY NOON. DIURNAL CU/SC THAT DVLP WITH
DAYTIME HEATING/MIXING UNDER LINGERING H85 THERMAL TROF WL TEND TO
DIMINISH OVER AT LEAST THE W AND CENTRAL WITH MORE EMPHATIC DRYING/
QUICKER TRANSITION TO MORE ACYC FLOW...BUT SC MAY LINGER LONGER OVER
THE E WHERE THE H85 TEMPS WARM ABV -10C ONLY TOWARD 00Z. MIXING TO
H85 AS OBSVD ON UPSTREAM 00Z RAOBS YIELDS HI TEMPS IN THE UPR 30S/
LO 40S OVER THE W...BUT ONLY 30 TO 35 OVER THE CNTRL AND E WHERE
LOWER H85 TEMPS LINGER LONGER. WITH WEAKER PRES GRADIENT ARRIVING
WITH SFC HI CENTER...LK BREEZES WL MAINTAIN LOCAL COOLING NEAR THE
SHORES. SOME HI CLDS WL ARRIVE OVER THE W IN THE AFTN WELL IN
ADVANCE OF PAC NW SHRTWV MOVING THRU THE NRN ROCKIES.
TNGT...AS SHRTWV MOVES THRU THE NRN PLAINS AND ASSOCIATED SFC LO
SHIFTS TO SW MN BY 12Z SAT...EXPECT THICKENING CLDS IN THE DVLPG WAD
PATTERN BTWN THE DEPARTING HI AND INCOMING LO PRES. VIGOROUS
ISENTROPIC ASCENT SHOWN ON THE 280-295K ISENTROPIC SFCS IS FCST TO
SPREAD W-E ACRS THE CWA AND SLOWLY SATURATE THE VERY DRY ANTECEDENT
LO-MID LVLS. FAVOR THE SOMEWHAT SLOWER 00Z NAM/CNDN AND 12Z ECMWF
FOR TIMING LEADING EDGE OF PCPN TIED TO H5-7 FGEN AXIS OVER THE
GFS...WHICH APPEARS TO GENERATE PCPN TOO DEEP INTO THE LINGERING DRY
AIR. THESE FAVORED MODELS INDICATE PCPN WL REACH A LINE FROM
MUNISING-MANISTIQUE BY 12Z SAT... SO RESTRICTED CATEGORICAL POPS TO
THE W OF THAT AXIS. FAVORED MODEL QPF INDICATES 2 TO 3 INCHES OF SN
OVER THE SW CWA BY 12Z SAT EVEN THOUGH RATHER NARROW/HI DGZ CENTERED
ARND 15K FT WL LIMIT SN/WATER RATIOS. EXPECT THE LOWEST MIN TEMPS
OVER THE INTERIOR E...WHERE THE CLDS WL ARRIVE LATEST AND WINDS BE
LGT IN THE EVNG TO ALLOW FOR GOOD RADIATIONAL COOLING. FOLLOWED A
NON-DIURNAL CURVE WITH TEMPS FALLING TO THE LOWEST LVL FAIRLY
EARLY...THEN STEADY OR SLOWLY RISING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 622 AM EDT FRI APR 5 2013
MAIN FCST CONCERNS FOCUS ON SYSTEM FOR SATURDAY...PTYPE
CONCERNS...POSSIBLE HEADLINES AND SNOW AMTS.
ACTIVE SHORTWAVE NOW MOVING IN OFF THE PACIFIC NW AS NOTED ON WATER
VAPOR LOOP IS EXPECTED TO TRACK DUE E...REACHING THE WRN GREAT LAKES
SAT. WHILE MODELS HAVE COME INTO BETTER AGREEMENT WITH TRACK/TIMING
OF SHORTWAVE AND ASSOC SFC LOW SOME IMPORTANT MODEL DIFFERENCES
REMAIN IN THERMAL FIELDS. CONFIDENCE IS HIGH THAT ALL OF THE FCST
AREA WILL SEE PCPN...SO HIGH CATEGORICAL POPS WILL BE PAINTED ACROSS
THE CWA. RIGHT ENTRANCE OF UPPER JET ASSOCIATED WITH ERN CANADA TROF
WILL PROVIDE LARGER SCALE ENHANCEMENT TO UPWARD MOTION...AS A FAIRLY
VIGOROUS FRONTOGENESIS SIGNATURE WILL AID PCPN INTENSITY ON THE
SMALLER SCALE. IT APPEARS THAT THERE MAY BE 2 PERIODS OF FGEN
FORCING...ONE INITIALLY LATE TONIGHT/SAT MORNING THAT
TRANSLATES ACROSS THE AREA...THEN A SECOND SAT AFTN/EVENING THAT
WOULD FAVOR CNTRL/ERN UPPER MI FOR HEAVIER PCPN. WITH MIXING RATIOS
OF 4-5G/KG AND CLOSE TO 12HRS OF ASCENT...THERE COULD BE 6 TO
POSSIBLY AS MUCH AS LOCALLY 8-10 INCHES OF HVY/WET SNOW ALONG THE
AXIS OF HEAVIEST PCPN WHERE PTYPE IS ALL SNOW. SO...DETERMINING THE
CONFIGURATION OF PTYPES WILL BE CRITICAL. IS STILL APPEARS THAT
PTYPE WILL BE ALL SNOW ACROSS THE FCST AREA AS PCPN DEVELOPS TONIGHT
...AND THAT SNOW MAY FALL LONG ENOUGH SO THAT A FEW INCHES OF SNOW
ACCUMULATE EVEN IN AREAS THAT SEE A MIX OR CHANGE TO RAIN DURING THE
DAY SAT. DURING THE DAY SAT...UNCERTAINTY GROWS IN HOW FAR N WARMING
OCCURS. THE 06Z GFS AND NAM BRINGS 0C 850MB ISOTHERM AND CRITICAL
1000-850MB THICKNESS FAR ENOUGH N SO THAT PERHAPS ONLY WEST AND NW
UPPER MI REMAINS MOSTLY SNOW SAT AFTN/EVENING. THE LOCAL WRF-ARW AND
REG-GEM ARE FARTHER S WITH THESE TEMP PARAMETERS AND ARE GENERALLY
MORE IN LINE WITH THE ECMWF...SUGGESTING MUCH OF NRN UPPER MI WILL
STAY MOSTLY SNOW. FCST SOUNDINGS STILL SUGGEST THAT A NARROW ZONE OF
SLEET IS ALSO POSSIBLE IN THE TRANSITION ZONE BTWN MOSTLY SNOW NORTH
TO MOSTLY RAIN SOUTH ON SAT. CONSIDERED ISSUING A WATCH FOR SOME THE
NRN COUNTIES IN SWATH OF EXPECTED HEAVIER PCPN WHERE PTYPE WILL BE
MOSTLY SNOW...BUT GIVEN CONTINUED UNCERTAINTIES WITH PTYPE AND
ULTIMATE ACCUMS DECIDED TO KEEP AN SPS GOING HIGHLIGHTING THE
POTENTIAL FOR VERY HVY/WET SNOW THAT WILL BE DIFFICULT TO
SHOVEL/PLOW AND WILL LEAD TO VERY DIFFICULT TRAVEL CONDITIONS.
ON SUN...SFC HIGH PRES WILL NOSE INTO THE UPPER LAKES BEHIND
SYSTEM...BRINGING AN INFLUX OF DRIER AIR. DAYTIME TEMPS SHOULD
RECOVER WELL INTO THE 30S/LWR 40S IN THE AFTN WITH SOME INCREASE IN
SUNSHINE DURING THE DAY.
FCST FOR MON THRU THU REMAINS UNCERTAIN. MUCH OF THE FCST WILL HINGE
ON THE STRENGTH OF THE LINGERING ERN CANADA TROF UNDER THE WEAKENING
NEGATIVE AO/NAO PATTERN. OTHER THAN A SHOWING A WEAK NRN PLAINS
SHORTWAVE MOVING THROUGH THE AREA LATE SUNDAY NIGHT INTO
MONDAY...THE LATEST ECMWF IS SIMILAR TO RECENT RUNS SHOWING A
STRONGER AND MORE PERSISTENT ERN CANADIAN TROF WHICH KEEPS A DRIER
WNW FLOW ACROSS THE UPPER LAKES FOR THE EARLY PART OF NEXT WEEK.
THIS IDEA ALSO WOULD GO ALONG WITH THE GENERAL PERSISTENT PATTERN
WHICH HAS DOMINATED THE REGION FOR THE LAST SEVERAL WEEKS...ALTHOUGH
IT REMAINS TO BE SEEN HOW LONG PATTERN WILL PERSIST GIVEN EXPECT
WEAKENING OF HIGH LATITUDE BLOCKING. THE 12Z ECMWF DOES FINALLY
BRING PCPN INTO THE FCST AREA ON WED NIGHT AND THU...MAINLY IN FORM
OF SNOW...AS MAIN PIECE OF ENERGY FROM WRN CONUS TROF EJECTS NE
TOWARD THE GREAT LAKES. MEANWHILE...THE LATEST 00Z RUN OF THE GFS
QUICKLY WEAKENS THE ERN CANADIAN TROF AND PUSHES IT EAST ALLOWING
FOR A STRONG SRN STREAM SHORTWAVE TO EJECT TOWARD THE UPPER GREAT
LAKES FM BASE OF WRN CONUS TROF. THE GFS SHOWS 8H TEMPS RISING TO
10-12C BY TUE NIGHT INTO WED ACCOMPANIED BY A SLUG OF GULF MOISTURE
(250-300 PCT OF NORMAL PWAT VALUES) WHICH WOULD YIELD A THREAT OF
MODERATE TO HEAVY RAIN TO THE FCST AREA TUE NIGHT INTO WED. THE 12Z
GEM-NH GENERALLY LENDS MORE SUPPORT TO ECMWF SOLN ALTHOUGH IT ALSO
TENDS TO BREAK DOWN ERN CANADIAN TROF QUICKER THAN ECMWF. GIVEN
CONSIDERABLE MODEL UNCERTAINTY...WILL CONTINUE SIMPLE CONSENSUS
APPROACH TO FCST KEEPING ONLY SCHC POPS FOR MON INTO TUE THEN
INCREASE POPS TO 30-40 PCT CHC FOR WED AND THU WITH THE IDEA THAT
ERN CANADA TROF WILL WEAKEN ALLOWING FOR MORE ENERGY FROM WRN CONUS
TROF TO REACH UPPER GREAT LAKES. TEMPS SHOULD REMAIN BLO NORMAL THRU
THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 732 AM EDT FRI APR 5 2013
ALTHOUGH THERE WL BE SOME SC AT MAINLY SAW INTO THIS AFTN...DRY
NATURE OF THE INCOMING AIRMASS ASSOCIATED WITH HI PRES MOVING INTO
MN WL BRING VFR CONDITIONS AT ALL 3 LOCATIONS INTO THIS EVNG.
THICKER CLDS AND THEN SN WL ARRIVE TNGT IN ADVANCE OF A LO PRES
SYSTEM MOVING THRU THE NRN PLAINS. EVEN BEFORE THE SN ARRIVES...CIGS
AT SAW MAY FALL INTO THE MVFR RANGE WITH UPSLOPE SE FLOW BTWN THE
DEPARTING HI/INCOMING LO PRES. EXPECT VSBYS TO DROP INTO THE IFR
CATEGORY AT ALL 3 LOCATIONS AFTER MIDNGT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 622 AM EDT FRI APR 5 2013
NW WINDS UP TO 25 KTS EARLY THIS MORNING OVER THE E HALF WILL
DIMINISH STEADILY TODAY AS HI PRES IS FORECAST TO BUILD OVER UPR MI
BY THIS AFTERNOON. LIGHT WINDS WILL SHIFT TO THE ESE AND INCREASE UP
TO 20 KTS TONIGHT AS THE NEXT LO PRES SYSTEM IS FORECAST TO MOVE TO
SW MN BY SAT MORNING. AS THE PRES GRADIENT TIGHTENS OVER LAKE SUP ON
SAT/SAT NIGHT TO THE N OF THE LO TRACKING THRU THE CENTRAL LAKES...
E-SE BACKING NE WINDS WILL INCREASE UP TO 25 TO 30 KTS BEFORE
DIMINISHING AND FURTHER BACKING TO THE N ON SUN AS TRAILING HI PRES
SHIFTS TOWARD THE UPPER LAKES. FOR EARLY NEXT WEEK...PLAN ON NE
WINDS UP TO 20 KTS ON THE SE FLANK OF HI PRES OVER CENTRAL CANADA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
624 AM EDT FRI APR 5 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 622 AM EDT FRI APR 5 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CONFLUENT NW FLOW
ALF OVER THE GRT LKS DOWNSTREAM OF RDG OVER THE ROCKIES. AT THE
LLVLS...THE CWA IS DOMINATING BY A NW FLOW OF COLDER AIR IN THE WAKE
OF THU COLD FROPA AND AHEAD OF SFC HI PRES NEAR LK WINNIPEG. SINCE
THE 00Z INL RAOB SHOWED A VERY DRY...INVERTED V PROFILE AND RECENT
SFC OBS INDICATE FAIRLY LARGE SFC T/TD SPREADS...SKIES ARE MOCLR
OVER UPR MI AS OF 06Z. BUT THE 00Z YPL RAOB DEPICTED A SOMEWHAT
MOISTER...BUT STILL WELL MIXED...SFC-H85 T/TD PROFILE WITH AN H85
TEMP DOWN TO -16C. FARTHER UPSTREAM...A SHRTWV IS MOVING INTO THE
PAC NW. WAD MID/HI CLDS WELL E OF THIS DISTURBANCE ARE SPREADING
INTO THE NRN PLAINS.
TODAY...ALTHOUGH SKIES ARE MOCLR EARLY THIS MRNG...SUSPECT SOME LK
CLDS/EVEN SOME -SHSN MIGHT DVLP OVER AREAS E OF MQT AS THE
MOISTER...COLDER AIRMASS SHOWN ON THE 00Z YPL RAOB WITH H85 TEMPS AS
LO AS -15C IMPACT THIS PART OF THE CWA. OVER THE W HALF...THE VERY
DRY 00Z INL RAOB IS MORE REPRESENTATIVE OF THE SOURCE AIRMASS. SO
REMOVED POPS/DIMINISHED FCST CLDS IN THIS AREA. BUT EVEN OVER THE
E...GENERALY ACYC NATURE OF THE FCST LLVL FLOW AS WELL AS HIER SFC
T/TD DEPRESSIONS EVEN FARTHER E N OF LK SUP SUG ANY SN ACCUMS WL BE
NEGLIGIBLE IF SHSN DO FORM AT ALL. WITH DAYTIME HEATING/LARGE SCALE
SUBSIDENCE AS SFC HI BLDS OVER THE W HALF OF THE CWA BY 18Z...EXPECT
ANY LES OVER THE E TO DIMINISH BY NOON. DIURNAL CU/SC THAT DVLP WITH
DAYTIME HEATING/MIXING UNDER LINGERING H85 THERMAL TROF WL TEND TO
DIMINISH OVER AT LEAST THE W AND CENTRAL WITH MORE EMPHATIC DRYING/
QUICKER TRANSITION TO MORE ACYC FLOW...BUT SC MAY LINGER LONGER OVER
THE E WHERE THE H85 TEMPS WARM ABV -10C ONLY TOWARD 00Z. MIXING TO
H85 AS OBSVD ON UPSTREAM 00Z RAOBS YIELDS HI TEMPS IN THE UPR 30S/
LO 40S OVER THE W...BUT ONLY 30 TO 35 OVER THE CNTRL AND E WHERE
LOWER H85 TEMPS LINGER LONGER. WITH WEAKER PRES GRADIENT ARRIVING
WITH SFC HI CENTER...LK BREEZES WL MAINTAIN LOCAL COOLING NEAR THE
SHORES. SOME HI CLDS WL ARRIVE OVER THE W IN THE AFTN WELL IN
ADVANCE OF PAC NW SHRTWV MOVING THRU THE NRN ROCKIES.
TNGT...AS SHRTWV MOVES THRU THE NRN PLAINS AND ASSOCIATED SFC LO
SHIFTS TO SW MN BY 12Z SAT...EXPECT THICKENING CLDS IN THE DVLPG WAD
PATTERN BTWN THE DEPARTING HI AND INCOMING LO PRES. VIGOROUS
ISENTROPIC ASCENT SHOWN ON THE 280-295K ISENTROPIC SFCS IS FCST TO
SPREAD W-E ACRS THE CWA AND SLOWLY SATURATE THE VERY DRY ANTECEDENT
LO-MID LVLS. FAVOR THE SOMEWHAT SLOWER 00Z NAM/CNDN AND 12Z ECMWF
FOR TIMING LEADING EDGE OF PCPN TIED TO H5-7 FGEN AXIS OVER THE
GFS...WHICH APPEARS TO GENERATE PCPN TOO DEEP INTO THE LINGERING DRY
AIR. THESE FAVORED MODELS INDICATE PCPN WL REACH A LINE FROM
MUNISING-MANISTIQUE BY 12Z SAT... SO RESTRICTED CATEGORICAL POPS TO
THE W OF THAT AXIS. FAVORED MODEL QPF INDICATES 2 TO 3 INCHES OF SN
OVER THE SW CWA BY 12Z SAT EVEN THOUGH RATHER NARROW/HI DGZ CENTERED
ARND 15K FT WL LIMIT SN/WATER RATIOS. EXPECT THE LOWEST MIN TEMPS
OVER THE INTERIOR E...WHERE THE CLDS WL ARRIVE LATEST AND WINDS BE
LGT IN THE EVNG TO ALLOW FOR GOOD RADIATIONAL COOLING. FOLLOWED A
NON-DIURNAL CURVE WITH TEMPS FALLING TO THE LOWEST LVL FAIRLY
EARLY...THEN STEADY OR SLOWLY RISING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 622 AM EDT FRI APR 5 2013
MAIN FCST CONCERNS FOCUS ON SYSTEM FOR SATURDAY...PTYPE
CONCERNS...POSSIBLE HEADLINES AND SNOW AMTS.
ACTIVE SHORTWAVE NOW MOVING IN OFF THE PACIFIC NW AS NOTED ON WATER
VAPOR LOOP IS EXPECTED TO TRACK DUE E...REACHING THE WRN GREAT LAKES
SAT. WHILE MODELS HAVE COME INTO BETTER AGREEMENT WITH TRACK/TIMING
OF SHORTWAVE AND ASSOC SFC LOW SOME IMPORTANT MODEL DIFFERENCES
REMAIN IN THERMAL FIELDS. CONFIDENCE IS HIGH THAT ALL OF THE FCST
AREA WILL SEE PCPN...SO HIGH CATEGORICAL POPS WILL BE PAINTED ACROSS
THE CWA. RIGHT ENTRANCE OF UPPER JET ASSOCIATED WITH ERN CANADA TROF
WILL PROVIDE LARGER SCALE ENHANCEMENT TO UPWARD MOTION...AS A FAIRLY
VIGOROUS FRONTOGENESIS SIGNATURE WILL AID PCPN INTENSITY ON THE
SMALLER SCALE. IT APPEARS THAT THERE MAY BE 2 PERIODS OF FGEN
FORCING...ONE INITIALLY LATE TONIGHT/SAT MORNING THAT
TRANSLATES ACROSS THE AREA...THEN A SECOND SAT AFTN/EVENING THAT
WOULD FAVOR CNTRL/ERN UPPER MI FOR HEAVIER PCPN. WITH MIXING RATIOS
OF 4-5G/KG AND CLOSE TO 12HRS OF ASCENT...THERE COULD BE 6 TO
POSSIBLY AS MUCH AS LOCALLY 8-10 INCHES OF HVY/WET SNOW ALONG THE
AXIS OF HEAVIEST PCPN WHERE PTYPE IS ALL SNOW. SO...DETERMINING THE
CONFIGURATION OF PTYPES WILL BE CRITICAL. IS STILL APPEARS THAT
PTYPE WILL BE ALL SNOW ACROSS THE FCST AREA AS PCPN DEVELOPS TONIGHT
...AND THAT SNOW MAY FALL LONG ENOUGH SO THAT A FEW INCHES OF SNOW
ACCUMULATE EVEN IN AREAS THAT SEE A MIX OR CHANGE TO RAIN DURING THE
DAY SAT. DURING THE DAY SAT...UNCERTAINTY GROWS IN HOW FAR N WARMING
OCCURS. THE 06Z GFS AND NAM BRINGS 0C 850MB ISOTHERM AND CRITICAL
1000-850MB THICKNESS FAR ENOUGH N SO THAT PERHAPS ONLY WEST AND NW
UPPER MI REMAINS MOSTLY SNOW SAT AFTN/EVENING. THE LOCAL WRF-ARW AND
REG-GEM ARE FARTHER S WITH THESE TEMP PARAMETERS AND ARE GENERALLY
MORE IN LINE WITH THE ECMWF...SUGGESTING MUCH OF NRN UPPER MI WILL
STAY MOSTLY SNOW. FCST SOUNDINGS STILL SUGGEST THAT A NARROW ZONE OF
SLEET IS ALSO POSSIBLE IN THE TRANSITION ZONE BTWN MOSTLY SNOW NORTH
TO MOSTLY RAIN SOUTH ON SAT. CONSIDERED ISSUING A WATCH FOR SOME THE
NRN COUNTIES IN SWATH OF EXPECTED HEAVIER PCPN WHERE PTYPE WILL BE
MOSTLY SNOW...BUT GIVEN CONTINUED UNCERTAINTIES WITH PTYPE AND
ULTIMATE ACCUMS DECIDED TO KEEP AN SPS GOING HIGHLIGHTING THE
POTENTIAL FOR VERY HVY/WET SNOW THAT WILL BE DIFFICULT TO
SHOVEL/PLOW AND WILL LEAD TO VERY DIFFICULT TRAVEL CONDITIONS.
ON SUN...SFC HIGH PRES WILL NOSE INTO THE UPPER LAKES BEHIND
SYSTEM...BRINGING AN INFLUX OF DRIER AIR. DAYTIME TEMPS SHOULD
RECOVER WELL INTO THE 30S/LWR 40S IN THE AFTN WITH SOME INCREASE IN
SUNSHINE DURING THE DAY.
FCST FOR MON THRU THU REMAINS UNCERTAIN. MUCH OF THE FCST WILL HINGE
ON THE STRENGTH OF THE LINGERING ERN CANADA TROF UNDER THE WEAKENING
NEGATIVE AO/NAO PATTERN. OTHER THAN A SHOWING A WEAK NRN PLAINS
SHORTWAVE MOVING THROUGH THE AREA LATE SUNDAY NIGHT INTO
MONDAY...THE LATEST ECMWF IS SIMILAR TO RECENT RUNS SHOWING A
STRONGER AND MORE PERSISTENT ERN CANADIAN TROF WHICH KEEPS A DRIER
WNW FLOW ACROSS THE UPPER LAKES FOR THE EARLY PART OF NEXT WEEK.
THIS IDEA ALSO WOULD GO ALONG WITH THE GENERAL PERSISTENT PATTERN
WHICH HAS DOMINATED THE REGION FOR THE LAST SEVERAL WEEKS...ALTHOUGH
IT REMAINS TO BE SEEN HOW LONG PATTERN WILL PERSIST GIVEN EXPECT
WEAKENING OF HIGH LATITUDE BLOCKING. THE 12Z ECMWF DOES FINALLY
BRING PCPN INTO THE FCST AREA ON WED NIGHT AND THU...MAINLY IN FORM
OF SNOW...AS MAIN PIECE OF ENERGY FROM WRN CONUS TROF EJECTS NE
TOWARD THE GREAT LAKES. MEANWHILE...THE LATEST 00Z RUN OF THE GFS
QUICKLY WEAKENS THE ERN CANADIAN TROF AND PUSHES IT EAST ALLOWING
FOR A STRONG SRN STREAM SHORTWAVE TO EJECT TOWARD THE UPPER GREAT
LAKES FM BASE OF WRN CONUS TROF. THE GFS SHOWS 8H TEMPS RISING TO
10-12C BY TUE NIGHT INTO WED ACCOMPANIED BY A SLUG OF GULF MOISTURE
(250-300 PCT OF NORMAL PWAT VALUES) WHICH WOULD YIELD A THREAT OF
MODERATE TO HEAVY RAIN TO THE FCST AREA TUE NIGHT INTO WED. THE 12Z
GEM-NH GENERALLY LENDS MORE SUPPORT TO ECMWF SOLN ALTHOUGH IT ALSO
TENDS TO BREAK DOWN ERN CANADIAN TROF QUICKER THAN ECMWF. GIVEN
CONSIDERABLE MODEL UNCERTAINTY...WILL CONTINUE SIMPLE CONSENSUS
APPROACH TO FCST KEEPING ONLY SCHC POPS FOR MON INTO TUE THEN
INCREASE POPS TO 30-40 PCT CHC FOR WED AND THU WITH THE IDEA THAT
ERN CANADA TROF WILL WEAKEN ALLOWING FOR MORE ENERGY FROM WRN CONUS
TROF TO REACH UPPER GREAT LAKES. TEMPS SHOULD REMAIN BLO NORMAL THRU
THE PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 127 AM EDT FRI APR 5 2013
VFR CONDITIONS EXPECTED THROUGH THE PERIOD AT ALL TAF SITES. PUT IN
A CHANCE OF SOME SNOW LATE IN THE EVENING IN IWD WITH POSSIBILITY OF
MVFR CIGS AND VIS AS NEXT WEATHER SYSTEM NEARS. THIS WILL CAUSE
CLOUDS TO THICKEN AND LOWER AT CMX AND SAW IN THE EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 622 AM EDT FRI APR 5 2013
NW WINDS UP TO 25 KTS EARLY THIS MORNING OVER THE E HALF WILL
DIMINISH STEADILY TODAY AS HI PRES IS FORECAST TO BUILD OVER UPR MI
BY THIS AFTERNOON. LIGHT WINDS WILL SHIFT TO THE ESE AND INCREASE UP
TO 20 KTS TONIGHT AS THE NEXT LO PRES SYSTEM IS FORECAST TO MOVE TO
SW MN BY SAT MORNING. AS THE PRES GRADIENT TIGHTENS OVER LAKE SUP ON
SAT/SAT NIGHT TO THE N OF THE LO TRACKING THRU THE CENTRAL LAKES...
E-SE BACKING NE WINDS WILL INCREASE UP TO 25 TO 30 KTS BEFORE
DIMINISHING AND FURTHER BACKING TO THE N ON SUN AS TRAILING HI PRES
SHIFTS TOWARD THE UPPER LAKES. FOR EARLY NEXT WEEK...PLAN ON NE
WINDS UP TO 20 KTS ON THE SE FLANK OF HI PRES OVER CENTRAL CANADA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...07
MARINE...KC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
623 AM CDT FRI APR 5 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT FRI APR 5 2013
A MODIFIED ARCTIC FRONT IS LINED UP FROM ROUGHLY KFNB TO KLBF TO
E-KIEN. THE FRONT WILL LIFT NORTH TODAY AS LOW
PRESSURE...CURRENTLY ACROSS NERN WY...MOVES EAST THROUGH SRN SD.
THE TEMPERATURE FCST USES 50 PERCENT OF THE RAP13 AND A BLEND OF
OTHER MODELS. THE RAP IS VERY WARM BUT GIVEN THE CLOUDS MOVING
IN...IT IS PROBABLY TOO WARM.
THE NAM RADAR AND THUNDERSTORM PRODUCTS SUGGEST ISOLATED HIGH
BASED SHRA AND TSTM THIS AFTN AND THIS EVENING. LITTLE OR NO
RAINFALL IS EXPECTED. AS THE SFC LOW TRACKS THROUGH SD TODAY AND
INTO SRN MN TONIGHT...A PACIFIC COLD FRONT WILL DROP THROUGH THE
FCST AREA. THIS WILL KEEP LOWS ON THE WARM SIDE WITH LOWS MAINLY
IN THE 40S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 356 AM CDT FRI APR 5 2013
SATURDAY WILL STILL BE ANOTHER MILD DAY AS MOSTLY SUNNY SKIES
BEHIND THE PACIFIC COLD FRONT PREVAIL. HIGHS SHOULD PUSH IN THE
60S WHICH IS DOWN ABOUT 10 TO 15 DEGREES FROM FRIDAY...BUT STILL
ABOVE NORMAL. SATURDAY NIGHT A TROUGH DEVELOPS ALONG THE FRONT
RANGE AND WILL BRING A SLIGHT CHANCE FOR SHOWERS TO THE EASTERN
PANHANDLE. MOISTURE IS LIMITED AND WILL HAVE TO OVERCOME A DRY
LOWER LAYER THUS EXPECT AMOUNTS LIGHT.
SUNDAY WILL SEE THE NEXT WAVE PUSH ONTO THE HIGH PLAINS. MOISTURE
IS LIMITED WITH PRECIP WATER ONLY AROUND 75 PERCENT OF
NORMAL...FOR APRIL. INSTABILITY INCREASES DURING THE AFTERNOON
WITH HEATING...AND SHOULD BE ENOUGH TO SET OFF SOME THUNDERSTORMS.
CAPE VALUES ONLY A FEW HUNDRED J/KG...HOWEVER GREATER VALUES NOT TO
FAR TO THE SOUTH IN KS.
NEXT WEEK WILL SEE A MAJOR LOW DIG TOWARDS THE 4 CORNERS THEN
EJECT ONTO THE PLAINS BY MID WEEK. THE MODELS CONTINUE TO
STRUGGLE ON TIMING AND STRENGTH OF THE SYSTEM...WHICH LEADS TO A
LOWER THAN AVERAGE CONFIDENCE IN FORECAST.
THE GFS CONTINUES TO BE A FASTER SOLUTION...WHILE THE ECMWF BRINGS
UP THE REAR. INITIALLY THINK AS THE LOW PUSHES TOWARDS THE
ROCKIES...SOME MOISTURE WILL ADVECT NORTH. WE MAY GET DRY SLOTTED
SUNDAY NIGHT INTO MONDAY...AHEAD OF THE LOW. HOWEVER PRECIP WATER
INCREASES TO AROUND AN INCH...WHICH IS CLOSER TO 2 SD...LATE
MONDAY. NEG LI/S SHOULD LEAD TO SOME SHOWERS AND THUNDER ACROSS
MOST OF THE AREA.
THEN AS THE UPPER LOW EJECTS ONTO THE PLAINS...WILL SEE SOME COLD
AIR DEVELOP ON THE BACK SIDE. THIS WILL ALSO WORK IN TANDEM WITH
COOL TEMPS AT NIGHT. WILL NEED TO MENTION SOME SN IN THE NW AND A
MIX TO THE SOUTH AND EAST. LATEST MEX GUIDANCE FOR TUES AND WED
HOLD DAYTIME HIGHS IN THE NW IN THE 30S. WHICH IS POSSIBLE AS THE
CLOUDS WILL LIMIT DIURNAL SWING. ANOTHER CONCERN IS THE TIGHT
PRESSURE GRADIENT...WHICH WILL CREATE SOME WINDY CONDITIONS. THE
SYSTEM IS VERY SLOW TO PUSH ACROSS THE PLAINS...WITH IMPACT
THROUGH AT LEAST EARLY WEDNESDAY.
FOR THE LATER PART OF THE WEEK A SECONDARY UPPER LEVEL DISTURBANCE
ROTATES DOWN ACROSS THE WESTERN PLAINS. ALTHOUGH MODELS HAVE HIGH
PRESSURE AT THE SURFACE...THE UPPER LEVEL WAVE SHOULD HAVE ENOUGH
MOISTURE TO STILL PRODUCE CLOUDS AND SOME LIGHT RAIN OR SNOW.
LONG WAY TROUGH FINALLY SHOULD BE EAST BY THURSDAY OR
FRIDAY...WITH A RIDGE TO THE WEST. THIS WILL RESULT IN NW FLOW AND
A TRAIN OF UPPER LEVEL SHORT WAVES. WILL LIKELY NEED TO MENTION AT
LEAST SOME LIGHT PRECIP TOWARDS THE END OF THE WEEK...HOWEVER
TIMING ISSUES ARE COMMON THIS FAR OUT AND WILL NOT BLANKET POPS.
WILL MONITOR AND ADD WHEN CONFIDENCE IS HIGHER ON LOCATION AND
TIMING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 619 AM CDT FRI APR 5 2013
VFR IS EXPECTED ALL AREAS TODAY AND TONIGHT. ISOLATED AFTERNOON
AND EVENING THUNDERSTORMS ARE POSSIBLE WITH THE APPROACH OF A
STRONG PACIFIC COLD FRONT. THE FRONT IS EXPECTED TO PRODUCE A
PERIOD OF GUSTY WINDS ACROSS NRN NEB TONIGHT. OTHERWISE SCT-BKN120-200
CIGS WILL CONTINUE THROUGH 06Z TONIGHT.
&&
.FIRE WEATHER...
ISSUED AT 356 AM CDT FRI APR 5 2013
A WEAKNESS IN THE WIND FIELDS IS SHOWING UP ACROSS SWRN NEB.
THUS...RELATIVE HUMIDITY WILL BE VERY LOW IN THAT AREA BUT WINDS
MAY NOT BE STRONG ENOUGH FOR CRITICAL FIRE DANGER. STRONGER WEST
WINDS SHOW UP ACROSS THE ERN NEB PANHANDLE. THESE WEST WINDS WILL
SWEEP EAST THIS AFTN TO NEAR KVTN AND KTIF. SOUTH WINDS CONTINUE
EAST OF HIGHWAY 83. PRESUMABLY...THIS WILL DRAW MORE MOIST AIR
NORTH FROM KS AND OKLAHOMA.
THE RAP MODEL IS VERY DRY AND SUGGESTS CRITICAL FIRE CONDITIONS
COULD SPREAD THROUGHOUT WESTERN AND NORTH CENTRAL NEB THIS
AFTERNOON. THIS IS AN OCCASIONAL BIAS THAT SHOWS IN THE MODEL BUT
IT SENSES THE DRYNESS OF THE ARCTIC AIR AND INCORPORATES IT INTO
THE AFTN WEATHER. THE MODEL COULD BE CORRECT TO A DEGREE. THE
BEST FORECAST IS A BLEND OF THE RAP WHICH IS VERY DRY AND THE
OTHER MODELS WHICH TEND TO BE TOO MOIST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 1 PM CDT /NOON MDT/ THIS AFTERNOON TO 8 PM
CDT /7 PM MDT/ THIS EVENING FOR NEZ204-210.
&&
$$
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...CDC
FIRE WEATHER...CDC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
738 AM EDT FRI APR 5 2013
.SYNOPSIS...
LOW PRESSURE SYSTEM JUST OFF THE NORTH CAROLINA COAST WILL
CONTINUE TO LIFT OFF TO THE NORTHEAST AWAY FROM THE AREA THROUGH
TODAY. HIGH PRESSURE WILL BUILD IN BEHIND THIS STORM SYSTEM...
BRINGING A WARMING TREND AND SPRING-LIKE TEMPERATURES THROUGH NEXT
WEEK. A MORE SUMMER-LIKE PATTERN SETS UP THROUGH MID WEEK AS BERMUDA
HIGH PRESSURE DOMINATES BEFORE A COLD FRONT APPROACHES FROM THE WEST
TOWARD LATE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...AN UPPER LEVEL DISTURBANCE MOVING RAPIDLY
NORTH THROUGH GEORGIA AND NOW SOUTH CAROLINA HAS PRODUCED AN
IMPRESSIVE AREA OF SHOWERS AND THUNDERSTORMS EXTENDING FROM
GEORGETOWN SC SOUTH BACK INTO WAYCROSS AND AMERICUS GA VICINITY.
THIS CONVECTION IS ELEVATED WITH THE LIFTING PARCEL LEVEL PROBABLY
IN THE VICINITY OF 10000 FT AGL OR 700 MB. LATEST RUC ANALYSIS SHOWS
LAPSE RATES IN THE 700-500 MB LAYER ARE EXCEEDING 7C/KM...AND
FORECAST SOUNDINGS FROM VIRTUALLY ANY MODEL SHOW STEEP LAPSE RATES
CONTINUING FOR AT LEAST ANOTHER 100 MB HIGHER IN THE ATMOSPHERE.
I HAVE INCREASED POPS MAINLY ALONG THE SC COAST AND OFFSHORE FOR THE
MORNING HOURS TO ACCOUNT FOR THIS ACTIVITY. FORTUNATELY THERE IS NO
SEVERE WEATHER THREAT OWNING TO THE DEEP FRONTAL INVERSION BELOW THE
STORMS AND SMALL CAPE VALUES ALOFT LIMITING POTENTIAL HAIL
PRODUCTION. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
SURFACE LOW PRESSURE MOVED ALMOST DIRECTLY OVER ILM AROUND MIDNIGHT.
NOW THAT THE LOW IS RACING NORTHEAST ACROSS EXTREME EASTERN NC COOL
AIR HAS RUSHED DOWN TO THE CAPE FEAR AND GRAND STRAND BEACHES. LOW
STRATUS CLOUDS WILL BE VERY TOUGH TO ERODE TODAY...AND IN FACT
MODELS SUGGEST A SOLID GRAY OVERCAST WILL PERSIST THROUGH THE
MORNING HOURS...RELUCTANTLY LIFTING INTO A SCT-BKN STRATOCUMULUS
DECK SOMETIME IN THE 11 AM TO 2 PM PERIOD. IT APPEARS THE NAM HAS A
BETTER HANDLE ON THE LATER CLOUD BURNOFF THAN THE GFS...THEREFORE MY
FORECAST HIGHS ARE CLOSE THE NAM AND RANGE FROM THE UPPER 50S NEAR
THE COAST TO AROUND 60 INLAND...10-13 DEGREES BELOW NORMAL.
OF MORE IMMEDIATE CONCERN IS A CLUSTER OF THUNDERSTORMS ACROSS
SOUTHERN GEORGIA ASSOCIATED WITH AN 500 MB VORT MAX ROTATING
NORTHEASTWARD AROUND THE MAIN UPPER LOW STILL BACK ON THE
MISSISSIPPI-ALABAMA BORDER. THIS CONVECTION APPEARS TO BE BASED
AROUND 700 MB AND IS TAKING ADVANTAGE OF STEEPENING LAPSE RATES IN
THE 700-400 MB LAYER AS COLD AIR WITH THE UPPER LOW ADVECTS ACROSS
THE SOUTHEAST. IT IS POSSIBLE THESE SHOWERS AND THUNDERSTORMS WILL
AFFECT COASTAL SOUTH CAROLINA LATER THIS MORNING...WHERE I HAVE A
30-40 PERCENT POP IN THE FORECAST. POPS ELSEWHERE ARE IN THE 10-20
PERCENT RANGE HEDGING FOR ANY EXPANSION IN THIS AREA OF ELEVATED
CONVECTION.
THE AFOREMENTIONED UPPER LOW WILL MOVE EAST ACROSS ALABAMA AND
GEORGIA THIS MORNING...THEN INTO SOUTH CAROLINA BY MID AFTERNOON.
LOW AND MID CLOUDS MAY CONTINUE ALONG THE COAST INTO THE EVENING
HOURS BUT CLEARING SKIES SHOULD DEVELOP FROM WEST TO EAST AS THE
UPPER LOW MOVES ACROSS. A NEW AREA OF SURFACE LOW PRESSURE WILL
DEVELOP WELL OFF THE GA/SC COAST LATE THIS AFTERNOON IN ADVANCE OF
THE UPPER SYSTEM. THIS NEW LOW SHOULD REMAIN TOO FAR AWAY FOR ANY
DIRECT IMPACTS ON OUR AREA...BUT NORTHERLY FLOW BEHIND THIS LOW WILL
HELP MAINLY A CHILLY AIRMASS ACROSS THE CAROLINAS TONIGHT WITH LOWS
FALLING TO 40-45...A FEW DEGREES BELOW NORMAL.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...HIGH PRESSURE WILL BUILD DOWN OVER THE
SOUTHEAST THROUGH THE WEEKEND. A COOLER NORTHERLY FLOW INITIALLY
WILL WEAKEN AND BECOME LIGHT AS IT VEERS AROUND THROUGH SAT NIGHT AS
CENTER OF HIGH SHIFTS CLOSER OVERHEAD AND THEN OFF SHORE BY
MORNING. THE MAX CAA WILL CUT OFF EARLY SATURDAY AS 850 TEMPS DROP
CLOSE TO 3C. EXPECT AFTERNOON HIGHS TO ONCE AGAIN REMAIN BELOW
NORMAL REACHING INTO THE LOW TO MID 60S. CALM WINDS AND CLEAR
SKIES SATURDAY NIGHT WILL PROVIDE MORE IDEAL RADIATIONAL COOLING
CONDITIONS WITH TEMPS DROPPING INTO THE LOWER END OF THE 40S MOST
PLACES...BUT SLIGHTLY WARMER AT THE BEACHES.
BY SUNDAY A RETURN FLOW WILL SET UP WITH LIGHT SOUTHERLY WINDS
BEGINNING A WARMING TREND INTO NEXT WEEK. TEMPS WILL APPROACH
NORMAL VALUES FOR THIS TIME OF YEAR WITH HIGH TEMPS JUST REACHING
INTO THE 70S UNDER PLENTY OF SUNSHINE.
OVERALL A BEAUTIFUL WEEKEND WITH LOTS OF SPRING SUNSHINE BUT
SLIGHTLY COOLER TEMPS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 3 AM FRIDAY...HEADING INTO A MORE SUMMER LIKE PATTERN FOR
THIS TIME OF YEAR. BERMUDA HIGH PRESSURE WITH A WARMER MOISTER
SOUTHERLY RETURN FLOW THROUGH THE PERIOD. A DEEP RIDGE BUILDS
ALOFT WITH HEIGHT RISES PEAKING MID WEEK UP CLOSE TO 585 DM.
AS THE MID TO UPPER RIDGE BUILDS UP THE EAST COAST A DEEPENING
TROUGH WILL DIG DOWN THROUGH THE MID WEST. ALTHOUGH THE RIDGE
HOLDS ON TIGHT THROUGH MUCH OF THE WORK WEEK...THE TROUGH FINALLY
MOVES EAST TOWARD THE AREA PUSHING A COLD FRONT OUR WAY BY THURS
NIGHT INTO FRIDAY. MODELS HAVE PUSHED THE TIMING BACK A BIT AND
THEREFORE LOOKS LIKE NICE WEATHER WILL HOLD OUT THROUGH THURSDAY.
OVERALL A RAIN FREE WEEK WITH A SHARP WARMING TREND BRINGING TEMPS
TO SEVERAL DEGREES ABOVE NORMAL WITH HIGH TEMPS FLIRTING WITH 80
OR SLIGHTLY ABOVE IN PLACES AND MIN TEMPS CLOSE TO WHAT WE HAVE
BEEN EXPERIENCING FOR HIGH TEMPS LATELY. THE COOLER OCEAN TEMPS
WILL MAXIMIZE THE DIFFERENTIAL HEATING ALLOWING FOR A STRONG SEA
BREEZE TO CARRY FAR INLAND MOST AFTERNOONS. THIS WILL BRING COOLER
AIR INLAND BUT WILL ALSO KEEP THE BEACHES MUCH COOLER.
THE SEA BREEZE WILL ALSO PROVIDE A FOCAL POINT FOR ENOUGH
CONVERGENCE TO PRODUCE CU EACH AFTERNOON AND MAY SEE SOME PASSING
HIGH CLOUDS BUT OTHERWISE SHOULD SEE A GOOD DEAL OF SUNSHINE
THROUGH THE WEEK WITH ANY PCP HOLDING OFF UNTIL LATE THURS INTO
FRIDAY.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 12Z...RADAR INDICATES SOME SHOWER ACTIVITY NEAR KMYR/KCRE IS
MOVING NORTHEAST UP THE CAROLINA COAST. MOST OF THE ACTIVITY IS
REMAINING OFFSHORE...AND DO NOT EXPECT ANY PCPN FOR KILM ATTM.
WIDESPREAD IFR CIGS ARE BEING REPORTED AT ALL TERMS THIS MORNING.
GFS AND NAM GUIDANCE IN GOOD AGREEMENT THAT IFR WILL PERSIST FOR
MUCH OF THE MORNING...ESPECIALLY ALONG THE COAST. KFLO/KLBT CIGS
WILL LIKELY LIFT ABOVE 1KFT BY MID TO LATE MORNING...WHEREAS
KILM/KMYR/KCRE COULD SEE IFR CONDITIONS LINGER UNTIL MIDDAY. ONCE
THE STRATUS FINALLY LIFTS...EXPECT MVFR IN THE EARLY AFTERNOON TO
BECOME VFR BY LATE AFTERNOON THROUGH THE END OF THE TAF PERIOD.
NORTHWEST WINDS AOB 12 KTS THIS MORNING WILL VEER TO THE NORTH LATER
TODAY...REMAINING AOB 10 KTS. THE SKIES WILL CLEAR OUT OVERNIGHT AS
AN UPPER LOW PUSHES THROUGH THE CAROLINAS.
EXTENDED OUTLOOK...VFR EXPECTED SATURDAY THROUGH TUESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...TWO CHANGES HAVE BEEN MADE TO THE MARINE
FORECAST THIS MORNING. THE FIRST IS TO INCREASE SHOWER AND T-STORM
CHANCES THROUGH THE MORNING HOURS AS THE WILMINGTON AND CHARLESTON
RADARS ARE SHOWING AN IMPRESSIVE AREA OF SHOWERS AND STORMS MOVING
RAPIDLY NORTHEAST ALONG THE COAST. THE SOUTH CAROLINA COASTAL WATERS
WILL BE MOST STRONGLY AFFECTED BY THIS ACTIVITY...WHICH SHOULD TAPER
OFF BY NOON. ALSO...OBSERVED WIND SPEEDS ARE ABOUT 5 KNOTS STRONGER
THAN EXPECTED ACROSS THE WATERS NORTH OF CAPE FEAR...WHERE RECENTLY
GUSTS AT BOTH WRIGHTSVILLE BEACH AND THE FRYING PAN SHOALS BUOY
OFFSHORE HAVE BEEN AROUND 20 KNOTS. NO OTHER SIGNIFICANT CHANGES
HAVE BEEN MADE. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
SURFACE LOW PRESSURE MOVED OVER WILMINGTON AROUND MIDNIGHT AND IS
NOW RACING NORTHEAST ACROSS THE PAMLICO SOUND. NORTHWESTERLY WINDS
BEHIND THIS LOW HAVE PUSHED THE COLD FRONT A CONSIDERABLE DISTANCE
FROM SHORE...AND COOL NORTHWEST TO NORTH WINDS SHOULD CONTINUE
THROUGH THE DAY. STRONG WINDS YESTERDAY STILL HAVE THE SEA STATE
QUITE AGITATED AND IT WILL TAKE MOST OF THE DAY FOR SEAS TO DECAY
BELOW 6 FEET. FOR THIS REASON THE SMALL CRAFT ADVISORY WILL REMAIN
POSTED INTO THE AFTERNOON HOURS FOR THE SC COASTAL WATERS...AND
UNTIL THIS EVENING FOR THE NC WATERS.
AN APPROACHING UPPER LEVEL LOW WILL INDUCE A NEW LOW TO DEVELOP WELL
OFF THE SC COAST LATE THIS AFTERNOON. WHILE THIS NEW LOW WILL HAVE
NO DIRECT IMPACTS LOCALLY...IT WILL HELP TO ENHANCE THE NORTHERLY
WINDS SOMEWHAT WITH WIND SPEEDS PERHAPS ECLIPSING 15 KNOTS
OVERNIGHT...ESPECIALLY AWAY FROM SHORE.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...HIGH PRESSURE WILL BUILD DOWN INTO THE LOCAL
WATERS THROUGH SATURDAY BEFORE SHIFTING CLOSER OVERHEAD SAT NIGHT
AND THEN OFF SHORE THROUGH SUNDAY. WINDS ON THE FRONT END OF THE
SYSTEM WILL BE NORTHEAST INITIALLY UP TO 15 TO 20 KTS BUT WILL VEER
AROUND THROUGH THE WEEKEND AND LIGHTEN TO 10 KTS OR SO AS GRADIENT
RELAXES. BY SATURDAY EVENING WINDS WILL BE VERY LIGHT OUT OF THE
E-NE AND BY SUNDAY A RETURN FLOW WILL SET UP AS WINDS VEER AROUND
TO THE SOUTH REMAINING 10 KTS OR LESS.
SEAS WILL JUST BE COMING DOWN FROM NEAR SCA CONDITIONS SAT
MORNING IN OUTER WATERS AND WILL CONTINUE TO SUBSIDE THROUGH THE
WEEKEND AS THEY VEER AROUND FROM NORTHEAST TO SOUTHEAST AND
LIGHTEN. BY SUNDAY SEAS WILL BE 3 FT OR LESS.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 3 AM FRIDAY...A MORE SUMMER LIKE PATTERN WILL BE SETTING
UP THROUGH NEXT WEEK AS RETURN FLOW PERSISTS AROUND BERMUDA HIGH
PRESSURE. WINDS WILL REMAIN SOUTHERLY AROUND 10 KTS OR SO. WINDS
AND SEAS WILL SPIKE UP NEAR SHORE IN FAIRLY POTENT SEA BREEZE EACH
AFTERNOON...BUT OTHERWISE EXPECT SEAS 3 FT OR LESS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 3 PM EDT THIS AFTERNOON FOR AMZ256.
SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR AMZ254.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR AMZ250-
252.
&&
$$
NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...BJR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
626 AM EDT FRI APR 5 2013
.SYNOPSIS...
LOW PRESSURE SYSTEM JUST OFF THE NORTH CAROLINA COAST WILL
CONTINUE TO LIFT OFF TO THE NORTHEAST AWAY FROM THE AREA THROUGH
TODAY. HIGH PRESSURE WILL BUILD IN BEHIND THIS STORM SYSTEM...
BRINGING A WARMING TREND AND SPRING-LIKE TEMPERATURES THROUGH NEXT
WEEK. A MORE SUMMER-LIKE PATTERN SETS UP THROUGH MID WEEK AS BERMUDA
HIGH PRESSURE DOMINATES BEFORE A COLD FRONT APPROACHES FROM THE WEST
TOWARD LATE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...AN UPPER LEVEL DISTURBANCE MOVING RAPIDLY
NORTH THROUGH GEORGIA AND NOW SOUTH CAROLINA HAS PRODUCED AN
IMPRESSIVE AREA OF SHOWERS AND THUNDERSTORMS EXTENDING FROM
GEORGETOWN SC SOUTH BACK INTO WAYCROSS AND AMERICUS GA VICINITY.
THIS CONVECTION IS ELEVATED WITH THE LIFTING PARCEL LEVEL PROBABLY
IN THE VICINITY OF 10000 FT AGL OR 700 MB. LATEST RUC ANALYSIS SHOWS
LAPSE RATES IN THE 700-500 MB LAYER ARE EXCEEDING 7C/KM...AND
FORECAST SOUNDINGS FROM VIRTUALLY ANY MODEL SHOW STEEP LAPSE RATES
CONTINUING FOR AT LEAST ANOTHER 100 MB HIGHER IN THE ATMOSPHERE.
I HAVE INCREASED POPS MAINLY ALONG THE SC COAST AND OFFSHORE FOR THE
MORNING HOURS TO ACCOUNT FOR THIS ACTIVITY. FORTUNATELY THERE IS NO
SEVERE WEATHER THREAT OWNING TO THE DEEP FRONTAL INVERSION BELOW THE
STORMS AND SMALL CAPE VALUES ALOFT LIMITING POTENTIAL HAIL
PRODUCTION. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
SURFACE LOW PRESSURE MOVED ALMOST DIRECTLY OVER ILM AROUND MIDNIGHT.
NOW THAT THE LOW IS RACING NORTHEAST ACROSS EXTREME EASTERN NC COOL
AIR HAS RUSHED DOWN TO THE CAPE FEAR AND GRAND STRAND BEACHES. LOW
STRATUS CLOUDS WILL BE VERY TOUGH TO ERODE TODAY...AND IN FACT
MODELS SUGGEST A SOLID GRAY OVERCAST WILL PERSIST THROUGH THE
MORNING HOURS...RELUCTANTLY LIFTING INTO A SCT-BKN STRATOCUMULUS
DECK SOMETIME IN THE 11 AM TO 2 PM PERIOD. IT APPEARS THE NAM HAS A
BETTER HANDLE ON THE LATER CLOUD BURNOFF THAN THE GFS...THEREFORE MY
FORECAST HIGHS ARE CLOSE THE NAM AND RANGE FROM THE UPPER 50S NEAR
THE COAST TO AROUND 60 INLAND...10-13 DEGREES BELOW NORMAL.
OF MORE IMMEDIATE CONCERN IS A CLUSTER OF THUNDERSTORMS ACROSS
SOUTHERN GEORGIA ASSOCIATED WITH AN 500 MB VORT MAX ROTATING
NORTHEASTWARD AROUND THE MAIN UPPER LOW STILL BACK ON THE
MISSISSIPPI-ALABAMA BORDER. THIS CONVECTION APPEARS TO BE BASED
AROUND 700 MB AND IS TAKING ADVANTAGE OF STEEPENING LAPSE RATES IN
THE 700-400 MB LAYER AS COLD AIR WITH THE UPPER LOW ADVECTS ACROSS
THE SOUTHEAST. IT IS POSSIBLE THESE SHOWERS AND THUNDERSTORMS WILL
AFFECT COASTAL SOUTH CAROLINA LATER THIS MORNING...WHERE I HAVE A
30-40 PERCENT POP IN THE FORECAST. POPS ELSEWHERE ARE IN THE 10-20
PERCENT RANGE HEDGING FOR ANY EXPANSION IN THIS AREA OF ELEVATED
CONVECTION.
THE AFOREMENTIONED UPPER LOW WILL MOVE EAST ACROSS ALABAMA AND
GEORGIA THIS MORNING...THEN INTO SOUTH CAROLINA BY MID AFTERNOON.
LOW AND MID CLOUDS MAY CONTINUE ALONG THE COAST INTO THE EVENING
HOURS BUT CLEARING SKIES SHOULD DEVELOP FROM WEST TO EAST AS THE
UPPER LOW MOVES ACROSS. A NEW AREA OF SURFACE LOW PRESSURE WILL
DEVELOP WELL OFF THE GA/SC COAST LATE THIS AFTERNOON IN ADVANCE OF
THE UPPER SYSTEM. THIS NEW LOW SHOULD REMAIN TOO FAR AWAY FOR ANY
DIRECT IMPACTS ON OUR AREA...BUT NORTHERLY FLOW BEHIND THIS LOW WILL
HELP MAINLY A CHILLY AIRMASS ACROSS THE CAROLINAS TONIGHT WITH LOWS
FALLING TO 40-45...A FEW DEGREES BELOW NORMAL.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...HIGH PRESSURE WILL BUILD DOWN OVER THE
SOUTHEAST THROUGH THE WEEKEND. A COOLER NORTHERLY FLOW INITIALLY
WILL WEAKEN AND BECOME LIGHT AS IT VEERS AROUND THROUGH SAT NIGHT AS
CENTER OF HIGH SHIFTS CLOSER OVERHEAD AND THEN OFF SHORE BY
MORNING. THE MAX CAA WILL CUT OFF EARLY SATURDAY AS 850 TEMPS DROP
CLOSE TO 3C. EXPECT AFTERNOON HIGHS TO ONCE AGAIN REMAIN BELOW
NORMAL REACHING INTO THE LOW TO MID 60S. CALM WINDS AND CLEAR
SKIES SATURDAY NIGHT WILL PROVIDE MORE IDEAL RADIATIONAL COOLING
CONDITIONS WITH TEMPS DROPPING INTO THE LOWER END OF THE 40S MOST
PLACES...BUT SLIGHTLY WARMER AT THE BEACHES.
BY SUNDAY A RETURN FLOW WILL SET UP WITH LIGHT SOUTHERLY WINDS
BEGINNING A WARMING TREND INTO NEXT WEEK. TEMPS WILL APPROACH
NORMAL VALUES FOR THIS TIME OF YEAR WITH HIGH TEMPS JUST REACHING
INTO THE 70S UNDER PLENTY OF SUNSHINE.
OVERALL A BEAUTIFUL WEEKEND WITH LOTS OF SPRING SUNSHINE BUT
SLIGHTLY COOLER TEMPS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 3 AM FRIDAY...HEADING INTO A MORE SUMMER LIKE PATTERN FOR
THIS TIME OF YEAR. BERMUDA HIGH PRESSURE WITH A WARMER MOISTER
SOUTHERLY RETURN FLOW THROUGH THE PERIOD. A DEEP RIDGE BUILDS
ALOFT WITH HEIGHT RISES PEAKING MID WEEK UP CLOSE TO 585 DM.
AS THE MID TO UPPER RIDGE BUILDS UP THE EAST COAST A DEEPENING
TROUGH WILL DIG DOWN THROUGH THE MID WEST. ALTHOUGH THE RIDGE
HOLDS ON TIGHT THROUGH MUCH OF THE WORK WEEK...THE TROUGH FINALLY
MOVES EAST TOWARD THE AREA PUSHING A COLD FRONT OUR WAY BY THURS
NIGHT INTO FRIDAY. MODELS HAVE PUSHED THE TIMING BACK A BIT AND
THEREFORE LOOKS LIKE NICE WEATHER WILL HOLD OUT THROUGH THURSDAY.
OVERALL A RAIN FREE WEEK WITH A SHARP WARMING TREND BRINGING TEMPS
TO SEVERAL DEGREES ABOVE NORMAL WITH HIGH TEMPS FLIRTING WITH 80
OR SLIGHTLY ABOVE IN PLACES AND MIN TEMPS CLOSE TO WHAT WE HAVE
BEEN EXPERIENCING FOR HIGH TEMPS LATELY. THE COOLER OCEAN TEMPS
WILL MAXIMIZE THE DIFFERENTIAL HEATING ALLOWING FOR A STRONG SEA
BREEZE TO CARRY FAR INLAND MOST AFTERNOONS. THIS WILL BRING COOLER
AIR INLAND BUT WILL ALSO KEEP THE BEACHES MUCH COOLER.
THE SEA BREEZE WILL ALSO PROVIDE A FOCAL POINT FOR ENOUGH
CONVERGENCE TO PRODUCE CU EACH AFTERNOON AND MAY SEE SOME PASSING
HIGH CLOUDS BUT OTHERWISE SHOULD SEE A GOOD DEAL OF SUNSHINE
THROUGH THE WEEK WITH ANY PCP HOLDING OFF UNTIL LATE THURS INTO
FRIDAY.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...THE SURFACE LOW MOVED ESSENTIALLY OVER ILM AROUND
MIDNIGHT AND IS NOW MOVING NE TOWARD THE NC OUTER BANKS. WINDS HAVE
SHIFTED TO NW ACROSS THE AREA AND SHOULD VEER MORE NORTHERLY AFTER
DAYBREAK. SOLID IFR/LIFR CIGS ARE EXPECTED TO PREVAIL THROUGH MUCH
OF THE MORNING HOURS. IFR/MVFR VSBYS DUE TO DZ SHOULD DISSIPATE BY
08Z AS THE CLOUD DEPTH THINS FROM ALOFT.
CIGS WILL BE SLOW TO LIFT LATER TODAY...PERHAPS TAKING UNTIL 14Z
INLAND AND 17Z AT THE COAST TO LIFT ABOVE 1000 FT AGL. VFR CIGS ARE
ANTICIPATED EVERYWHERE BY MID AFTERNOON. AN UPPER LEVEL LOW WILL
DRIFT OVER THE REGION EARLY IN THE EVENING...WITH NO FLIGHT CATEGORY
CHANGES ANTICIPATED. NORTHERLY SFC WINDS AROUND 10 KNOTS WILL
DIMINISH AFTER DARK.
EXTENDED OUTLOOK...EXPECT VFR SATURDAY THROUGH TUESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...TWO CHANGES HAVE BEEN MADE TO THE MARINE
FORECAST THIS MORNING. THE FIRST IS TO INCREASE SHOWER AND T-STORM
CHANCES THROUGH THE MORNING HOURS AS THE WILMINGTON AND CHARLESTON
RADARS ARE SHOWING AN IMPRESSIVE AREA OF SHOWERS AND STORMS MOVING
RAPIDLY NORTHEAST ALONG THE COAST. THE SOUTH CAROLINA COASTAL WATERS
WILL BE MOST STRONGLY AFFECTED BY THIS ACTIVITY...WHICH SHOULD TAPER
OFF BY NOON. ALSO...OBSERVED WIND SPEEDS ARE ABOUT 5 KNOTS STRONGER
THAN EXPECTED ACROSS THE WATERS NORTH OF CAPE FEAR...WHERE RECENTLY
GUSTS AT BOTH WRIGHTSVILLE BEACH AND THE FRYING PAN SHOALS BUOY
OFFSHORE HAVE BEEN AROUND 20 KNOTS. NO OTHER SIGNIFICANT CHANGES
HAVE BEEN MADE. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
SURFACE LOW PRESSURE MOVED OVER WILMINGTON AROUND MIDNIGHT AND IS
NOW RACING NORTHEAST ACROSS THE PAMLICO SOUND. NORTHWESTERLY WINDS
BEHIND THIS LOW HAVE PUSHED THE COLD FRONT A CONSIDERABLE DISTANCE
FROM SHORE...AND COOL NORTHWEST TO NORTH WINDS SHOULD CONTINUE
THROUGH THE DAY. STRONG WINDS YESTERDAY STILL HAVE THE SEA STATE
QUITE AGITATED AND IT WILL TAKE MOST OF THE DAY FOR SEAS TO DECAY
BELOW 6 FEET. FOR THIS REASON THE SMALL CRAFT ADVISORY WILL REMAIN
POSTED INTO THE AFTERNOON HOURS FOR THE SC COASTAL WATERS...AND
UNTIL THIS EVENING FOR THE NC WATERS.
AN APPROACHING UPPER LEVEL LOW WILL INDUCE A NEW LOW TO DEVELOP WELL
OFF THE SC COAST LATE THIS AFTERNOON. WHILE THIS NEW LOW WILL HAVE
NO DIRECT IMPACTS LOCALLY...IT WILL HELP TO ENHANCE THE NORTHERLY
WINDS SOMEWHAT WITH WIND SPEEDS PERHAPS ECLIPSING 15 KNOTS
OVERNIGHT...ESPECIALLY AWAY FROM SHORE.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...HIGH PRESSURE WILL BUILD DOWN INTO THE LOCAL
WATERS THROUGH SATURDAY BEFORE SHIFTING CLOSER OVERHEAD SAT NIGHT
AND THEN OFF SHORE THROUGH SUNDAY. WINDS ON THE FRONT END OF THE
SYSTEM WILL BE NORTHEAST INITIALLY UP TO 15 TO 20 KTS BUT WILL VEER
AROUND THROUGH THE WEEKEND AND LIGHTEN TO 10 KTS OR SO AS GRADIENT
RELAXES. BY SATURDAY EVENING WINDS WILL BE VERY LIGHT OUT OF THE
E-NE AND BY SUNDAY A RETURN FLOW WILL SET UP AS WINDS VEER AROUND
TO THE SOUTH REMAINING 10 KTS OR LESS.
SEAS WILL JUST BE COMING DOWN FROM NEAR SCA CONDITIONS SAT
MORNING IN OUTER WATERS AND WILL CONTINUE TO SUBSIDE THROUGH THE
WEEKEND AS THEY VEER AROUND FROM NORTHEAST TO SOUTHEAST AND
LIGHTEN. BY SUNDAY SEAS WILL BE 3 FT OR LESS.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 3 AM FRIDAY...A MORE SUMMER LIKE PATTERN WILL BE SETTING
UP THROUGH NEXT WEEK AS RETURN FLOW PERSISTS AROUND BERMUDA HIGH
PRESSURE. WINDS WILL REMAIN SOUTHERLY AROUND 10 KTS OR SO. WINDS
AND SEAS WILL SPIKE UP NEAR SHORE IN FAIRLY POTENT SEA BREEZE EACH
AFTERNOON...BUT OTHERWISE EXPECT SEAS 3 FT OR LESS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 3 PM EDT THIS AFTERNOON FOR AMZ256.
SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR AMZ254.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR AMZ250-
252.
&&
$$
NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...TRA/DL
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
657 AM CDT FRI APR 5 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 341 AM CDT FRI APR 5 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A SHORTWAVE TROUGH OVER THE PACIFIC NORTHWEST...RIDGING FROM
WEST TEXAS INTO THE NORTHERN PLAINS...AND NORTHERN STREAM TROUGHING
IN THE GREAT LAKES. IN THE WAKE OF THIS TROUGHING...HIGH PRESSURE
HAS BEEN BUILDING IN AT THE SURFACE ACROSS MINNESOTA. 00Z MPX
SOUNDING SHOWED PLENTY OF SUBSIDENCE AND DRY AIR ACCOMPANYING THE
SURFACE HIGH...WITH PRECIPITABLE WATER VALUE AT 0.28 INCHES. AS A
RESULT...SKIES ARE CLEAR ACROSS THE FORECAST AREA. JUST OFF TO THE
WEST...MID AND HIGH LEVEL CLOUDS WERE INCREASING ACROSS THE NORTHERN
PLAINS INTO WESTERN MINNESOTA...WELL DOWNSTREAM OF THE PACIFIC
NORTHWEST SHORTWAVE. THESE CLOUDS ARE ASSOCIATED WITH A WARM
ADVECTION REGIME ON THE TOP OF THE RIDGE...AS WELL AS HELP FROM A
120KT JET STREAK FROM SOUTHERN MANITOBA INTO EASTERN MINNESOTA.
PROFILER AND VAD WIND DATA AT 850MB SHOWED A 30-50 KT SOUTH JET FROM
EASTERN COLORADO INTO THE WESTERN DAKOTAS. ALSO PRESENT AT 850MB WAS
A TIGHT TEMPERATURE GRADIENT...REFLECTED BY 00Z SOUNDINGS OF -6C AT
BISMARCK COMPARED TO +5C AT RAPID CITY AND +10C AT NORTH PLATTE.
DESPITE THE DECENT WARM ADVECTION PATTERN IN PLACE...SURFACE
DEWPOINTS HAVE BEEN SLOW TO RISE. DEWPOINTS WERE ONLY IN THE LOW TO
MID 30S OVER THE CENTRAL PLAINS...WHICH WAS AT LEAST HIGHER THAN IN
THE DAKOTAS WHICH WERE IN THE 20S.
THE FOCUS FOR THE SHORT TERM IS ON TWO PARTS...
1. WARM ADVECTION WELL DOWNSTREAM OF THE PACIFIC NORTHWEST SHORTWAVE
TROUGH
2. EVENTUAL APPROACH OF THE PACIFIC NORTHWEST SHORTWAVE TROUGH
SUBSIDENCE AND DRY AIR ASSOCIATED WITH THE SURFACE HIGH WILL
DOMINATE THIS MORNING. AS WE HEAD INTO THE AFTERNOON...THE UPPER
RIDGE AXIS OVER THE NORTHERN PLAINS IS PROGGED TO SLIDE INTO THE
FORECAST AREA. THUS...AN INCREASE OF THE MID AND HIGH LEVEL CLOUDS
IS LIKELY AS SEEN BACK IN THE DAKOTAS. THE QUESTIONS ARE WILL
PRECIPITATION DEVELOP...AND IF SO WHERE AND WHEN...AS THE WARM
ADVECTION INCREASES THROUGH THE AFTERNOON AND EVENING. THE 05.00Z
GFS/REGIONAL CANADIAN ARE BY FAR THE MOST AGGRESSIVE...DEVELOPING
RAIN ALONG/WEST OF THE MISSISSIPPI RIVER BETWEEN 18-00Z TODAY. THE
05.00Z NAM/05.00Z ECMWF/04.21Z SREF ALSO DEVELOP THE RAIN...BUT KEEP
IT CONFINED NORTHWEST OF THE FORECAST AREA PRIOR TO 00Z. THE LACK OF
MOISTURE CURRENTLY AVAILABLE WOULD SUPPORT THE DRIER SCENARIO...
HOWEVER...850MB MOISTURE TRANSPORT DOES INTENSIFY THROUGH THE DAY
AND BY 00Z IS POINTING ON THE WEST SIDE OF THE FORECAST AREA.
THUS...FELT AT LEAST KEEPING SOME 20-50 PERCENT CHANCES LATE IN THE
DAY ARE APPROPRIATE OVER THE WESTERN PORTIONS OF THE FORECAST
AREA...HIGHEST FROM WABASHA INTO DODGE COUNTIES.
FOR TONIGHT...MODELS PROG THE PACIFIC NORTHWEST SHORTWAVE TROUGH TO
ENTER WESTERN SOUTH DAKOTA...CAUSING A SURFACE LOW TO FORM AND
DEEPEN OVER SOUTHERN SOUTH DAKOTA. PERSISTENT AND INTENSIFYING WARM
ADVECTION AHEAD OF THIS SHORTWAVE TROUGH AND SURFACE LOW LOOKS TO
EXPAND THE AREA OF PRECIPITATION OVER MOST LOCATIONS EAST OF THE
MISSISSIPPI RIVER IN THE EVENING...WHICH THEN LIFTS NORTHEAST AFTER
MIDNIGHT. EVAPORATIVE COOLING MAY CAUSE THE PRECIPITATION TO SWITCH
FROM RAIN TO SNOW IN THE EVENING NORTHEAST OF I-94...BUT EVENTUALLY
WARMER AIR ADVECTS IN THERE AFTER MIDNIGHT ALOFT AND THEN SURFACE
TO CAUSE A CHANGE-OVER TO SLEET AND RAIN. IF TEMPERATURES CAN HOLD
BELOW FREEZING...A VERY BRIEF PERIOD OF FREEZING RAIN WOULD OCCUR.
MODEL CONSENSUS CONTINUES TO FAVOR ALONG/NORTHEAST OF I-94 TO HAVE
THE BULK OF THE PRECIPITATION...THUS PRECIPITATION CHANCES NEAR 100
SEEMS REASONABLE. REGARDING SNOWFALL ACCUMULATION...GIVEN THE
GENERAL WARM SENSE TO THIS WARM ADVECTION EVENT...NOTED BY 850MB
TEMPS THAT ARE ONLY -2 TO -4C WHEN IT IS SNOWING...SNOW TO WATER
RATIOS SHOULD ONLY MAX OUT AROUND 10 TO 1. WITH UPWARDS OF 0.1-0.3
INCHES OF QPF PROGGED...SNOW TOTALS COULD BE AS MUCH AS 3
INCHES...THOUGH THE MAJORITY SHOULD END UP IN THE 1 TO 2 INCH
RANGE...NOT ENOUGH FOR AN ADVISORY AT THIS POINT. COULD USE THE MIX
PRECIPITATION AS A NEED FOR THE ADVISORY...BUT CONFIDENCE ON THE
AMOUNT OF MIXED PRECIPITATION IS TOO LOW TO WARRANT ONE.
TEMPERATURES TODAY WILL END UP COOLER COMPARED TO YESTERDAY DUE TO
INCREASING CLOUDS AS WELL AS 850MB TEMPS BETWEEN -2 AND -6C AT 18Z.
FOR TONIGHT...INCREASING SOUTHERLY WINDS PLUS CLOUDS SHOULD HELP
KEEP TEMPERATURES UP AT OR ABOVE FREEZING. IN FACT...EXPECTING
TEMPERATURES TO CLIMB LATE IN THE NIGHT AS THE SURFACE WARM FRONT
LIFTS NORTH TOWARDS I-94.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 341 AM CDT FRI APR 5 2013
HIGHLIGHTS:
1. CURRENT PACIFIC NORTHWEST SHORTWAVE TROUGH PROGGED TO MOVE
THROUGH THE AREA ON SATURDAY
2. POTENTIAL FOR AN ACTIVE BUT HARD TO TIME PRECIPITATION PATTERN
SUNDAY NIGHT AND BEYOND.
MODELS ARE IN REALLY GOOD AGREEMENT TRACKING THE SHORTWAVE TROUGH
THAT WAS OVER SOUTH DAKOTA LATE TONIGHT INTO AND POSSIBLY THROUGH
THE FORECAST AREA ON SATURDAY. STRONG DYNAMIC FORCING WITH THIS
SHORTWAVE...NOTED SIMPLY BY 60-90 METER HEIGHT FALLS IN 12 HOURS AT
500MB...ALONG WITH THAT SURGE OF 850MB MOISTURE TRANSPORT AHEAD OF
THE SHORTWAVE PROVIDING MOISTURE SHOULD HELP PRODUCE RAIN ACROSS
MOST OF THE FORECAST AREA. THE ONLY MODEL NOT SHOWING THIS IS THE
05.00Z NAM...AT LEAST SOUTH OF I-90...WHICH SEEMS ODD GIVEN THE
FORCING. THE 05.00Z REGIONAL CANADIAN IS ACTUALLY QUITE ROBUST SOUTH
OF I-90 WITH QPF AMOUNTS OF 0.1-0.25 INCHES WITH A FEW ISOLATED 0.5
INCH AMOUNTS FROM VERNON INTO ADAMS COUNTIES. IT APPEARS THE HEAVIER
QPF IS A RESULT OF CONVECTIVE ELEMENTS FORMING AHEAD OF THE
SHORTWAVES ASSOCIATED COLD FRONT AT THE SURFACE. INSTABILITY IS
FAIRLY MEAGER DUE TO CAPPING AROUND 750MB AND LIMITED MOISTURE.
HOWEVER...THERE IS A ZONE OF NEGATIVE EPV DUE TO UPRIGHT INSTABILITY
IN CROSS-SECTIONS AROUND 700MB...THUS A FEW THUNDERSTORMS CANNOT BE
RULED OUT. PRECIPITATION SHOULD SHIFT OFF TO THE EAST PRETTY QUICK
LATE IN THE AFTERNOON INTO THE EARLY EVENING FOR MOST OF THE
AREA...AS STRONG SUBSIDENCE COMES IN BEHIND THE SHORTWAVE TROUGH.
ONLY PLACE THIS MAY NOT OCCUR AS FAST IS NORTH AND EAST OF
I-94...DUE TO THE SUGGESTION OF A SHORTWAVE COMING IN BEHIND THE
SHORTWAVE TROUGH AND A MID-LEVEL FRONTOGENESIS ZONE DROPPING
SOUTHEAST. TEMPERATURES MAY COOL ENOUGH TO ALLOW FOR SOME SNOW OUT
OF THIS PRECIPITATION BEFORE IT ENDS BY MIDNIGHT. VERY LITTLE
ACCUMULATION ANTICIPATED...THOUGH.
A MAJOR PATTERN CHANGE IS FORECAST TO TAKE PLACE SUNDAY AS A POTENT
SHORTWAVE TROUGH IMPACTS AND DIGS INTO THE PACIFIC NORTHWEST.
HEADING INTO THE EARLY PORTION OF THE WORK WEEK...MODELS ARE IN GOOD
AGREEMENT DIGGING THIS TROUGH SOUTH INTO THE FOUR CORNERS REGION...
SETTING UP A SOUTHWEST FLOW PATTERN INTO THE FORECAST AREA. THIS
MEANS HARD TO TIME SHORTWAVES AND THUS PLENTY OF UNCERTAINTY. TAKE
FOR EXAMPLE SUNDAY NIGHT WHERE THE 05.00Z ECMWF/NAM BRING A
SHORTWAVE THROUGH THE AREA WITH WIDESPREAD QPF. THE 05.00Z CANADIAN
IS EVEN MORE POTENT WITH THIS SHORTWAVE AND A BIT FARTHER SOUTHEAST.
ON THE OTHER HAND...THE 05.00Z GFS DOES NOT SHOW THE SHORTWAVE AT
ALL...THUS RESULTING IN A DRY FORECAST. MAJORITY HERE SUGGESTS AT
LEAST 30-50 PERCENT PRECIPITATION CHANCES ARE NEEDED. MOST OF THE
PRECIPITATION SHOULD FALL AS RAIN...BUT COULD MIX WITH SNOW
ALONG/NORTHEAST OF I-94.
THE MOST INTERESTING TIME PERIOD OF NEXT WEEK IS TUESDAY INTO
WEDNESDAY...AS THE UPPER TROUGH IN THE SOUTHWEST U.S. EJECTS OUT.
THERE REMAINS A WHOLE LOT OF UNCERTAINTY ON THE TIMING AND DETAILS
OF THIS EJECTION. HOWEVER...EVERY MODEL AVAILABLE AT THIS POINT HAS
SOME SYSTEM AFFECTING THE AREA. WE COULD END UP SEEING CONVECTION IN
THE GFS SCENARIO...POTENTIAL FOR MODERATE TO HEAVY RAINFALL IN ANY
MODEL...AND EVEN SOME SNOW ON THE BACK SIDE OF THE SYSTEM ONCE THE
UPPER TROUGH MOVES OVERHEAD. WE WILL HAVE TO KEEP A WATCH ON THIS
PERIOD. GIVEN THE CONSENSUS AGREEMENT FOR PRECIPITATION TUESDAY INTO
TUESDAY NIGHT...RAISED PRECIPITATION CHANCES DURING THIS PERIOD. MAY
NEED TO RAISE CHANCES FOR WEDNESDAY AS WELL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 652 AM CDT FRI APR 5 2013
CLOUDS WILL MOVE INTO THE AREA LATE THIS MORNING AND AFTERNOON
AHEAD OF A LOW PRESSURE SYSTEM MOVING OUT OF THE NORTHERN PLAINS.
CEILINGS WILL QUICKLY DROP FROM 10K FEET TO AROUND 3500 FEET.
THESE CEILINGS WILL REMAIN BETWEEN 2500 AND 3500 FEET FOR THE
REMAINDER OF THE PERIOD. SHOWERS WILL MOVE INTO KRST AROUND 05.19Z
AND KLSE 05.22Z. DUE TO MODEL INCONSISTENCY...THERE ARE SOME
QUESTIONS ON WHETHER THERE WILL BE SOME DRY PERIODS TONIGHT. SINCE
THIS WAS STILL A BIT UNCLEAR...JUST KEPT THE THREAT OF SHOWERS
GOING FOR THE REMAINDER OF THE FORECAST.
&&
.HYDROLOGY...
ISSUED AT 341 AM CDT FRI APR 5 2013
RIVER STATUS...
HYDROGRAPHS ACROSS THE AREA SHOW TRIBUTARY RIVERS AND STREAMS INTO
THE MISSISSIPPI RUNNING WITHIN BANK FLOWS WITH A FEW HIGHER THAN
NORMAL GIVEN THE SNOW MELT. MOST OF THE HIGH RIVER FLOWS ARE
CONFINED TO RIVERS NORTH OF I-90 WHERE SNOW PACK STILL EXISTS. THE
WHITEWATER...TREMPEALEAU AND BLACK RIVERS ARE OF CONCERN AT THE
MOMENT.
SNOW PACK...
LATEST NOHRSC DATA SHOWED SNOW WATER EQUIVALENTS STILL IN THE 1-2
INCH RANGE OVER WINONA...BUFFALO...TREMPEALEAU AND JACKSON
COUNTIES...WHILE 2-3 INCH AMOUNTS WERE PRESENT IN CLARK AND TAYLOR
COUNTIES.
RAINFALL...
THE SYSTEM COMING IN FOR TONIGHT AND SATURDAY NOW LOOKS TO NOT
PRODUCE AS MUCH RAINFALL AS PREVIOUSLY EXPECTED...MOSTLY LESS THAN
1/3 OF AN INCH SOUTHWEST OF I-94 TO 1/3 TO 1/2 INCH NORTH OF I-94.
NOTE THAT SOME SNOW IS FORECAST TONIGHT NORTH AND EAST OF
I-94...WHICH COULD TOTAL UP TO 0.3 OF LIQUID EQUIVALENT. ADDITIONAL
RAINFALL IS POSSIBLE SUNDAY NIGHT WITH POTENTIAL FOR MODERATE TO
HEAVY RAINFALL TUESDAY INTO WEDNESDAY OF NEXT WEEK.
TEMPERATURES...
A COOLER DAY BUT STILL PLENTY WARM ENOUGH FOR SNOW MELT IS EXPECTED
TODAY AS HIGHS CLIMB INTO THE 40S. PROBLEM TONIGHT IS THAT
TEMPERATURES MAY NOT FALL BELOW FREEZING AND WITH WARMER CONDITIONS
ANTICIPATED ON SATURDAY...WE COULD REALLY SEE SOME SNOW MELT. MOST
OF THE NEXT 7 DAYS LOOK TO HAVE DAYTIME TEMPERATURES AT LEAST
40...THUS FAVORABLE CONDITIONS ARE IN PLACE FOR SNOW MELT EVERY DAY.
FROST DEPTH...
FROST REMAINS FAIRLY DEEP IN THE GROUND STILL. AS OF 7 AM APRIL
4TH...CUBA CITY WI WAS AT 16 INCHES...WHITEHALL WAS AT 19
INCHES...AND BLOOMER IN CHIPPEWA COUNTY WAS AT 38 INCHES.
SUMMARY...
NOW THAT LESS RAINFALL IS FORECAST THAN EXPECTED FOR TONIGHT AND
SATURDAY...ANY FLOODING CONCERN WOULD COME MOSTLY FROM SNOW MELT THE
NEXT FEW DAYS. CERTAINLY ANY RIVERS AND STREAMS FROM WINONA AND
WABASHA COUNTIES INTO BUFFALO TREMPEALEAU...JACKSON...CLARK AND
TAYLOR WOULD BE OF CONCERN. HAVE DECIDED TO KEEP THE ESF GOING
AND EXPANDED IT INTO WINONA COUNTY GIVEN THE ISSUES BEING
EXPERIENCED ON THE WHITEWATER RIVER. CONSIDERED ISSUING A FLOOD
WATCH FOR JUST RIVERS...BUT GIVEN THAT LESS RAINFALL IS EXPECTED
AND WE ALREADY HAVE EXPERIENCED RIVERS IN AND OUT OF MINOR FLOOD
STAGE THE LAST FEW DAYS...FEEL THE ESF IS STILL VALID. MAY STILL
NEED A FLOOD WATCH...THOUGH...AS CERTAINTY INCREASES ABOUT THE
AMOUNT OF SNOW MELT THIS WEEKEND. EITHER WAY...DEFINITELY NEED TO
KEEP AN EYE ON TUESDAY INTO WEDNESDAY OF NEXT WEEK.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS MIAMI FL
134 PM EDT FRI APR 5 2013
.AVIATION...
MOSTLY VFR CONDITIONS WITH BKN-OVC100 AND OCCASIONAL BKN035 WITH A
PASSING SHRA. SOME LIGHT RAIN IS ALSO POSSIBLE UNTIL EARLY EVENING
WHEN CLOUDS MOVE OUT TO THE EAST OF THE PENINSULA. SURFACE WIND
HAS BEEN WEAKER THAN EARLIER THINKING DUE TO RAIN COOLED AIRMASS
ALONG WITH OVERCAST MID TO HIGH CLOUDS. COULD HAVE SOME GUSTS OVER
12KT WITH SW FLOW THEN VEERING TO THE NW BEHIND THE COLD FRONT
BECOMING NNE AFT 12-13Z SATURDAY.
KOB
&&
.PREV DISCUSSION... /ISSUED 953 AM EDT FRI APR 5 2013/
UPDATE...
CURRENT WAVE OF PRECIPITATION THIS MORNING ACROSS LAKE OKEECHOBEE
TO SOUTHWEST FLORIDA, THEN DOWN INTO THE SE GULF OF MEXICO MAKING
STEADY EASTWARD PROGRESS AHEAD OF THE POWERFUL SHORTWAVE TROUGH OVER
THE EASTERN GULF OF MEXICO. ATMOSPHERE HAS STABILIZED IN THE LOW
LEVELS IN THE WAKE OF THE OVERNIGHT AND EARLY MORNING CONVECTION,
WHICH IS ACTING TO LIMIT THE INTENSITY OF THE ACTIVITY CURRENTLY
MOVING OVER THE AREA. SOUTHERLY FLOW TRYING TO DESTABILIZE THE
LOW LEVELS THIS MORNING, BUT OVERCAST CLOUD SHIELD WILL MITIGATE
ANY SIGNIFICANT WARMING AND SPC HAS APPROPRIATELY DOWNPLAYED THE
SEVERE THREAT ACROSS SOUTH FLORIDA TODAY.
FORECAST UPDATE HAS NUMEROUS SHOWERS AND ISOLATED TSTMS,
GRADUALLY TAPERING OFF FROM NW TO SE AS THE COLD FRONT CURRENTLY
APPROACHING THE TAMPA BAY REGION MOVES INTO THE AREA THIS
AFTERNOON. LOWERED TEMPERATURES A FEW DEGREES DUE TO COOLER
READINGS THIS MORNING AND EXTENSIVE CLOUD COVER.
INTERESTING TIDBIT: A "WAKE LOW" FEATURE WAS NOTED EARLY THIS
MORNING OVER PARTS OF SOUTH FLORIDA WHICH HELPED TO PRODUCE NON-
THUNDERSTORM WIND GUSTS OF 35 TO 45 MPH IN THE NAPLES AREA AS WELL
AS LAKE OKEECHOBEE AND PARTS OF THE PALM BEACHES. THIS IS THE SAME
TYPE OF FEATURE WHICH PRODUCED THE STRONG WINDS IN THE MOBILE AREA
BACK ON WEDNESDAY, AND THIS HAS BEEN NOTED IN PAST SPRINGTIME
CONVECTION EVENTS OVER SOUTH FLORIDA AND OTHER PARTS OF THE
SOUTHERN UNITED STATES. /MOLLEDA
PREV DISCUSSION... /ISSUED 831 AM EDT FRI APR 5 2013/
AVIATION...
A BAND OF LIGHT RAIN WILL MOVE ACROSS SOUTH FLORIDA INTO EARLY
THIS AFTERNOON WITH SOME MVFR CIGS/VISIBILITIES BUT MOSTLY VFR. IT
IS POSSIBLE DEPENDING ON ANY BREAKS IN THE CLOUD COVER THAT A FEW
THUNDERSTORMS COULD ALSO DEVELOP BY EARLY THIS AFTERNOON AHEAD OF
THE FRONT. THESE CONDITIONS WILL DIMINISH THIS AFTERNOON AS THE
COLD FRONT CLEARS THE PENINSULA. SURFACE WIND WILL BE SSW TO SW
INCREASING IN SPEEDS AND OCCASIONALLY GUSTING OVER 20KT AFT 13-14Z
SHIFTING TO THE NORTHWEST BEHIND THE FRONT.
KOB
PREV DISCUSSION... /ISSUED 343 AM EDT FRI APR 5 2013/
DISCUSSION...
AN MCS WAS MOVING ACROSS THE EASTERN GULF AND SOUTH FLORIDA EARLY
THIS MORNING. AN UPPER LEVEL LOW WAS MOVING EAST ACROSS
ALABAMA...WITH BROAD SURFACE LOW PRESSURE AREAS FROM NORTHERN
FLORIDA NORTHWARD TO OFF THE COAST OF NORTH CAROLINA. GLOBAL
MODELS ARE NOT HANDLING THE CURRENT SITUATION WELL...SO FOLLOWED
CLOSER TO THE HRRR OUTPUT THROUGH THE AFTERNOON.
THE ATMOSPHERE OVER SOUTH FLORIDA IS EXPECTED TO BECOME WORKED
OVER FROM THIS MCS...WITH MUCH MORE STABLE CONDITIONS. CLOUD
COVER WILL BLANKET THE REGION FOR MUCH OF THE DAY. SO THE SEVERE
THREAT APPEARS TO HAVE DIMINISHED...WITH THE LAST STRONG STORMS
ACROSS THE FAR SOUTHEASTERN PORTIONS OF MIAMI DADE COUNTY EARLY
THIS MORNING. SO LIGHT/MODERATE RAIN WITH A FEW EMBEDDED
THUNDERSTORMS ARE ALL THAT IS EXPECTED THROUGH THE MID/LATE
AFTERNOON...BEFORE THE COLD FRONT PUSHES THROUGH THE REGION.
UNDERCUT MAV/MET TEMPERATURES AT MOST LOCATIONS TODAY DUE TO THE
EXPECTED CLOUD COVER AND RAIN.
A FEW LINGERING SHOWERS ARE POSSIBLE INTO THE EARLY EVENING.
OTHERWISE...DRIER AND COOLER CONDITIONS ARE EXPECTED OVER SOUTH
FLORIDA TONIGHT. THE WEEKEND LOOKS LIKE IT WILL BE A PLEASANT
ONE WITH TEMPERATURES NEAR NORMAL FOR EARLY APRIL. A LIGHT TO
MODERATE NORTHEASTERLY FLOW WILL PREVAIL ON SATURDAY...WITH WINDS
SHIFTING TO THE EAST ON SUNDAY AS HIGH PRESSURE MOVES INTO THE
WESTERN ATLANTIC OFF THE EASTERN CONUS.
HIGH PRESSURE WILL REMAIN OVER THE WESTERN ATLANTIC THROUGH THE
MIDDLE OF THE WEEK...WITH LOW LEVEL MOISTURE RETURNING TO THE
REGION. HIGHS WILL REMAIN IN THE LOW 80S EAST TO THE MID TO UPPER
80S TOWARD THE GULF COAST. OVERNIGHT LOW TEMPERATURES WILL
INCREASE TO THE LOWER 70S FOR THE EAST COAST METRO AREAS. A FEW
STREAMER SHOWERS WILL BE POSSIBLE EACH DAY FROM TUESDAY THROUGH
THE END OF THE WEEK.
AVIATION...06Z TAFS.
MATURE MCS MOVING ACROSS THE EASTERN GULF AND
ACROSS SOUTH FLORIDA EARLY THIS MORNING. STRONG TO SEVERE STORMS
ARE POSSIBLE AT KFXE SOUTHWARD ON THE EAST COAST OVER THE NEXT FEW
HOURS. PREVAILING MVFR CONDITIONS ARE EXPECTED FOR MOST OF THE
EAST COAST TAF SITES THROUGH THE OVERNIGHT HOURS...WITH IFR
CONDITIONS POSSIBLE IN THUNDERSTORMS. KAPF IS IN THE RAIN SHIELD
ON THE NORTH SIDE OF THE MCS...AND LIGHT/MODERATE RAIN WITH A FEW
HIGH BASED LIGHTNING STRIKES WILL CONTINUE THROUGH THE MORNING
HOURS. LIGHT/MODERATE RAIN IS EXPECTED AFTER 10-12Z ACROSS THE
REGION AS THE MCS MOVES THROUGH AND SOUTH FLORIDA GETS WORKED
OVER. AT THIS TIME IS IT DIFFICULT TO SAY WHETHER THERE WILL BE
ANY REGENERATION OF THUNDERSTORMS BY THE AFTERNOON HOURS DUE TO
ALL THE CLOUD COVER. BASED OFF OF LATEST GUIDANCE...WILL ONLY SHOW
RAIN AFTER 12-14Z...WITH CONDITIONS IMPROVING BY MID/LATE
AFTERNOON. THE FRONT IS EXPECTED TO PASS THROUGH THE REGION
18-21Z...WITH LIGHT/MODERATE NORTHWESTERLY FLOW THROUGH THE END OF
THE TAF PERIOD.
MARINE...
LATEST GUIDANCE INDICATES THAT WINDS ACROSS THE LOCAL GULF AND
ATLANTIC WATERS COULD REACH AROUND 20 KNOTS THIS MORNING AND SEAS
ACROSS THE OFF SHORE GULF WATERS COULD REACH NEAR 7 FEET. A SMALL
CRAFT ADVISORY IS IN EFFECT THROUGH 00Z THIS EVENING FOR ALL OF
THE LOCAL WATERS. A COLD FRONT WILL MOVE THROUGH THE REGION LATE
THIS AFTERNOON...WITH WINDS SHIFTING TO THE NORTHWEST BEHIND THE
FRONT. NORTHEAST WINDS 15-20 KNOTS ARE EXPECTED ON SATURDAY...WITH
EASTERLY WINDS 10-15 KNOTS ON SUNDAY. EAST TO SOUTHEAST WINDS ARE
THEN EXPECTED THROUGH THE WEEK AS HIGH PRESSURE BUILDS ACROSS THE
WESTERN ATLANTIC.
FIRE WEATHER...
MUCH NEEDED RAINFALL WILL CONTINUE TO FALL ACROSS MUCH OF THE
REGION THROUGH THE DAY TODAY. A FEW EMBEDDED THUNDERSTORMS ARE
POSSIBLE INTO THE AFTERNOON. A COLD FRONT WILL MOVE THROUGH THE
REGION LATE THIS AFTERNOON INTO THIS EVENING...WITH DRIER AND
COOLER CONDITIONS EXPECTED TONIGHT. MINIMUM RELATIVE HUMIDITY
VALUES AND SATURDAY ARE EXPECTED TO REMAIN JUST ABOVE CRITICAL
VALUES ACROSS THE INTERIOR WEST. HIGH PRESSURE WILL THEN BUILD
ACROSS THE WESTERN ATLANTIC SUNDAY THROUGH THE MIDDLE OF THE
WEEK...WITH LOW LEVEL MOISTURE RETURNING TO SOUTH FLORIDA.
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR BISCAYNE
BAY-COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL
OUT 20 NM-COASTAL WATERS FROM JUPITER INLET TO DEERFIELD
BEACH, FL OUT 20 NM-LAKE OKEECHOBEE-WATERS FROM DEERFIELD
BEACH TO OCEAN REEF, FL EXTENDING FROM 20 NM TO THE
TERRITORIAL WATERS OF THE BAHAMAS-WATERS FROM JUPITER INLET
TO DEERFIELD BEACH, FL EXTENDING FROM 20 NM TO 60 NM.
GM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR COASTAL
WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT
20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL
EXTENDING FROM 20 TO 60 NM.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
327 PM CDT FRI APR 5 2013
.SYNOPSIS...
ISSUED AT 109 PM CDT FRI APR 5 2013
12Z UA ANALYSIS HAS AN 850MB COLD FRONT FROM THE MID ATLANTIC STATES
INTO SOUTHEAST IOWA. A RIDGE RAN FROM SOUTHERN TEXAS TO LAKE
WINNIPEG IN CANADA AND A LLJ RAN FROM WEST TEXAS INTO WESTERN
NEBRASKA. SATELLITE TRENDS THROUGH MID DAY SHOW INCREASING MID AND
HIGH LEVEL CLOUDS ACROSS THE MID MISSISSIPPI VALLEY.
18Z SFC ANALYSIS HAS A LOW ALONG THE NE/SD BORDER NEAR KIEN WITH A
WARM FRONT INTO SOUTH DAKOTA AND THEN DROPPING SOUTH ALONG THE
MISSOURI RIVER. THE MODIFIED ARCTIC FRONT WAS INTO THE TENNESSEE
VALLEY AND SOUTHERN MISSOURI. DEW POINTS OVER THE GREAT LAKES WERE
IN THE TEENS AND 20S WITH 30S AND 40S IN THE CENTRAL AND SOUTHERN
PLAINS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 109 PM CDT FRI APR 5 2013
THE DRY AIR IS HAMPERING THE DEVELOPMENT OF THE WAA PRECIPITATION
WING FROM MN INTO WISCONSIN. HOWEVER...RAP TRENDS WITH THE 850-700MB
CONDENSATION PRESSURE DEFICITS COMBINED WITH OVERALL
FORCING/CONVERGENCE AGREE QUITE NICELY WITH THE PRECIPITATION
APPROACHING THE MISSISSIPPI RIVER AROUND KMSP.
USING THIS AS A GUIDE THERE MAY BE SOME ISOLATED SHRA/SPRINKLES THAT
IMPINGE ALONG THE NORTHERN BORDER OF THE CWFA LATE THIS AFTERNOON
AND EARLY EVENING. ONCE THE FORCING SHIFTS NORTHEAST OF THE AREA BY
SUNSET...DRY CONDITIONS SHOULD THEN BE SEEN ACROSS THE AREA THROUGH
MIDNIGHT.
AFTER MIDNIGHT THINGS GET MORE INTERESTING.
THE MCS AND LIFT TOOLS ARE SUGGESTING CONVECTION DEVELOPING JUST
WEST OF I-35 IN THE STRENGTHENING LLJ BY MIDNIGHT. IF THE RAP TRENDS
ARE CORRECT THIS CONVECTION OF SHRA/TSRA SHOULD BE ON THE WESTERN
BORDER OF THE CWFA BY 09Z AND OVER THE WESTERN HALF OF THE CWFA BY
SUNRISE. THE COMBINATION OF THE LLJ AND STEEP MID LEVEL LAPSE RATES
SHOULD MAINTAIN THE CONVECTION AND ALSO RESULT IN WINDS INCREASING
DURING THE NIGHT.
THE ABOVE MENTIONED CONVECTION SHOULD EXIT THE CWFA BY LATE MORNING
AND THERE SHOULD BE A BRIEF PAUSE BEFORE NEW DIURNAL CONVECTION
DEVELOPS BY MID DAY AND CONTINUES THROUGH THE AFTERNOON HOURS.
LOW LEVEL LAPSE RATES BECOME QUITE STEEP AND THE WAA IS QUITE STRONG
ON SATURDAY WHICH WILL ALLOW THE HIGHER MOMENTUM AIR ALOFT TO MIX
DOWN. WINDS ARE EXPECTED TO PICK UP SIGNIFICANTLY BY LATE MORNING
AND CONTINUE THROUGH THE AFTERNOON.
THE SITUATION SATURDAY WILL NEED TO BE WATCHED CAREFULLY. THE
POTENTIAL DOES EXIST FOR A LOW END WIND ADVISORY FOR AREAS ALONG AND
EAST OF THE MISSISSIPPI FROM LATE MORNING THROUGH THE AFTERNOON
HOURS. ..08..
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 109 PM CDT FRI APR 5 2013
SATURDAY NIGHT AND SUNDAY SHOULD BE RELATIVELY QUIET AS A RIDGE OF
THE HIGH PRESSURE NOSES INTO THE REGION FROM THE NORTH. SOME LOW
CHANCE POPS WERE MAINTAINED EAST OF THE MISSISSIPPI RIVER SATURDAY
EVENING TO COVER ANY LINGERING SHOWERS BEHIND THE DEPARTING COLD
FRONT. BY SUNDAY MORNING THE COLD FRONT SHOULD BE STALLED OVER
CENTRAL OR NORTHERN MO WITH THE HIGH PRESSURE RIDGE OVER THE
NORTHERN CWFA. THIS SHOULD KEEP DRY WEATHER OVER MUCH OF THE AREA
THROUGH THE DAY SUNDAY. HOWEVER...KEPT SOME LOW POPS GOING IN THE
FAR SOUTH IN THE AFTERNOON WITH THE SURFACE FRONT JUST TO THE
SOUTH.
SUNDAY NIGHT A LOW AMPLITUDE S/W WILL MOVE THROUGH THE REGION
SPAWNING SHOWERS AND THUNDERSTORMS ALONG AND NORTH OF THE STALLED
FRONT. THE 00Z ECMWF WAS GENERATING SOME QPF WITH THIS FEATURE
OVER THE WESTERN CWFA AS EARLY AS SUNDAY AFTERNOON. BUT THE
FORCING SHOWN BY THE ECMWF WOULD SHOW MORE FAVORABLE CONDITIONS
OVER WESTERN IOWA BEFORE 00Z. OTHER THAN THE LOW CHANCE POPS IN
THE SOUTH SUNDAY AFTERNOON DISCUSSED ABOVE...THE SIGNIFICANT POPS
WERE LIMITED TO SUNDAY NIGHT WITH LIKELY/S OVER THEN ENTIRE AREA
WHEN AN AREA OF SHOWERS AND THUNDERSTORMS SHOULD MOVE EAST ACROSS
THE REGION AHEAD OF THE MID LEVEL SHORTWAVE. AT THIS POINT THE
SEVERE THUNDERSTORMS THREAT LOOKS NIL DUE LOW INSTABILITY AND
UNIMPRESSIVE FORCING. PW/S OVER THE AREA SUNDAY NIGHT ARE EXPECTED
TO BE AROUND AN INCH SUGGESTING GENERAL RAINFALL AMOUNTS OF A HALF
TO THREE QUARTERS OF AN INCH. THE HIGHER AMOUNTS WOULD FAVOR THE
SOUTH CLOSE TO THE SURFACE FRONT.
SHOWER AND THUNDERSTORM CHANCES WILL REMAIN OVER THE AREA MONDAY
THROUGH WEDNESDAY. THE LARGE TROF DEVELOPING OVER THE WESTERN U.S.
WILL CONTINUE TO FEED AMPLE MOISTURE INTO THE CENTRAL U.S. WHERE A
FRONTAL BOUNDARY WILL REMAIN. DURING THIS TIME FRAME...TUESDAY INTO
WEDNESDAY HAVE THE BEST CHANCE FOR SIGNIFICANT RAINS WHEN THE MODELS
SHOW A SURFACE LOW EJECTING NORTHEAST OUT OF THE SOUTHERN PLAINS
AHEAD OF THE UPPER TROF. EVEN THOUGH THIS FEATURE IS SHOWN BY ALL
MODELS THERE CONTINUES TO BE A VARIETY OF SOLUTIONS ON THE DETAILS
OF THE TRACK AND TIMING. THE 12Z ECMWF HAS SHIFTED THE TRACK
FURTHER SOUTHEAST SUGGESTING THE SIGNIFICANT RAINS WILL MISS THE
FORECAST AREA. THE GEM/GFS TRACK THE SYSTEM OVER IOWA TUESDAY OR
TUESDAY NIGHT SUPPORTING ANOTHER ROUND OF AT LEAST MODERATE RAINS.
GIVEN THE AMOUNT OF MOISTURE INPLACE AND A SURFACE BOUNDARY IN
THE AREA THE THREAT OF RAIN STILL LOOKS GOOD MONDAY THROUGH
WEDNESDAY WITH THE BIGGEST QUESTION NOW BEING THE RAINFALL
AMOUNTS. SO HAVE CONTINUED TO MENTION LIKELY POPS OVER MUCH OF THE
AREA FOR SHOWERS AND THUNDERSTORMS. THEN WEDNESDAY WHEN THE UPPER
TROF MOVES THROUGH...POPS WERE BACKED DOWN TO CHANCE CATEGORY.
COLDER AIR ADVECTING IN BEHIND THE TROF WEDNESDAY NIGHT COULD
PRODUCE A MIX OF RAIN AND SNOW ESPECIALLY NORTH. HOWEVER PRECIP
AMOUNTS SHOULD BE LIGHT MAKING IT UNLIKELY THAT ANY ACCUMULATION
WILL OCCUR. PRECIP COULD LINGER INTO THURSDAY AND THURSDAY NIGHT
WITH H8 TEMPS REMAINING BELOW ZERO. HOWEVER... TEMPERATURES NEAR
THE SURFACE SHOULD BE WARM ENOUGH FOR ALL RAIN.
DEEP SOUTHERLY FLOW AND HIGH MOISTURE LEVELS WILL KEEP
TEMPERATURES ON THE MILD SIDE EARLY NEXT WEEK...BUT BELOW NORMAL
READINGS WILL RETURN FOR THE END OF THE WEEK AS THE COLDER AIR
MOVES IN BEHIND THE DEPARTING UPPER TROF.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 109 PM CDT FRI APR 5 2013
VFR WX WILL BE SEEN THROUGH 06Z/06 WITH A POSSIBLE VCSH AT KDBQ
THROUGH SUNSET. AFT 06Z/06 MAINLY VFR WX IS EXPECTED TO CONTINUE
WITH POSSIBLE SHRA/TSRA AFFECTING ALL TAF SITES AFT 09Z/06. THE
POTENTIAL STILL EXISTS FOR LLWS IN THE 09Z-15Z/06 TIME FRAME. NEW
CONVECTION IS EXPECTED TO DEVELOP ACROSS IOWA/ILLINOIS AFT 15Z/06
AND BECOME MORE NUMEROUS AFT 18Z/06. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...08
SHORT TERM...08
LONG TERM...DLF
AVIATION...08
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
138 PM EDT FRI APR 5 2013
.UPDATE...
ISSUED AT 1254 PM EDT FRI APR 5 2013
GIVEN LARGER SPRING STORM IS QUICKLY ON THE APPROACH...THOUGHT
IT WOULD BE GOOD TO PROVIDE UPDATE IN TERMS OF EXPECTED STORM
INTENSITY/PTYPE AND HEADLINES.
SFC TROUGH THAT EVENTUALLY WILL DEVELOP INTO CLOSED OFF LOW OVER
WESTERN LAKES LATER SATURDAY IS CURRENTLY ALLIGNED FROM SOUTHERN
PORTIONS OF ALBERTA AND SASKATCHEWAN INTO NORTHERN US ROCKIES. 12Z
RAOBS AND WV LOOP SHOW H5 TROUGH PUSHING OUT OF WA/OR...WHILE TROUGH
AT H85 AND H7 IS CLOSER TO THE MAIN SFC LOW. SNOW IS AS CLOSE AS
ND/SASKATCHEAN BORDER ON EDGE OF H8-H7 FRONTOGENESIS. NAM/GFS AND
REGIONAL GEM INITIALIZED LARGER SCALE FEATURES WELL BUT DIFFER ON
CRITICAL THERMAL DETAILS FOR SATURDAY.
OVERALL...AT THE LEAST...WINTER WEATHER ADVISORIES WILL BE POSTED
LATER THIS AFTN FOR ALL OF CWA. ALREADY COORD WITH DLH AND GRB WHICH
HAVE ADVYS UP AND ALSO WITH APX. SOME AREAS MAY NEED WARNINGS BUT IT
WILL DEPEND ON WHERE PTYPE REMAINS MOSTLY SNOW FOR THE EVENT.
UNFORTUNATELY...THIS IS NOT CLEAR CUT EVEN WITHIN 24 HRS AS SOME
MODELS /GFS AND UKMET/ ARE PRETTY WARM AT H85-H8 DURING THE AFTN
HOURS ON SATURDAY /UP TO +3C AT H85/ WHILE NAM/REGIONAL GEM AND 00Z
ECMWF ARE NOT AS WARM. THIS IS ESPECIALLY TOUGH CONSIDERING THEY ARE
FAIRLY SIMILAR WITH H85/H7/H5 FEATURES. AS WOULD BE EXPECTED WITH
THERMAL PROFILES...GFS/SREF ARE SLIGHTLY FARTHER NORTH WITH SFC LOW.
GIVEN STEEP LAPSE RATES IN MID-LEVELS FEEDING INTO AREA OF
PRECIPITATION OVER UPR MICHIGAN...THERE IS ALSO CONCERN CONVECTION
WILL MODULATE INTENSITY AND PTYPE OVER THE CWA.
AT THIS POINT...FAR SOUTH SEEMS PRETTY CERTAIN TO SEE MAINLY RAIN BY
SATURDAY AFTN SO SNOW AMOUNTS WILL ULTIMATELY BE HELD DOWN FROM IMT
TO ESC AND CERTAINLY SOUTH TO MNM. GOGEBIC AND IRON TOUGH CALL AS
INITIAL WARM NOSE MAY RESULT IN MIX OF SLEET/SNOW AND EVEN RAIN LATE
TONIGHT INTO SATURDAY MORNING BUT PRECIP WOULD TURN BACK TO MAINLY
SNOW ON SATURDAY AFTN AS H7-H5 TROUGH/PRIMARY SHORTWAVES/LARGER
SCALE LIFTING AND DYNAMIC COOLING ARRIVE. MUCH MORE OF A QUESTION
IN THE TIER OF COUNTIES NORTH...FROM ONTONAGON/SOUTHERN HOUGHTON
THROUGH BARARA/MARQUETTE AND EAST TO ALGER/SCHOOLCRAFT/LUCE COUNTY.
IN THESE AREAS INITIAL SHOT OF PRECIP SATURDAY MORNING SHOULD REMAIN
MOSTLY SNOW AS THINK THAT DYNAMIC COOLING TIED TO STRONG H8-H5 FGEN
OFFSETS SHALLOW WARM LAYER H85-H8 AROUND +1C. INITIAL SURGE OF
PRECIP DRIVEN BY 295-305K /H85-H5/ ISENTROPIC ASCENT AND DIVERGENCE
ALOFT FROM LARGE JET STREAK OVER ONTARIO INTO QUEBEC COULD END AS
MIX OF SLEET/SNOW AS DYNAMIC COOLING FADES BTWN 15Z-18Z. STILL MANY
DETAILS TO BE SORTED OUT BUT WINTER WEATHER STATEMENT WITH FINAL
HEADLINE DECISIONS WILL BE OUT LATER THIS AFTN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 622 AM EDT FRI APR 5 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CONFLUENT NW FLOW
ALF OVER THE GRT LKS DOWNSTREAM OF RDG OVER THE ROCKIES. AT THE
LLVLS...THE CWA IS DOMINATING BY A NW FLOW OF COLDER AIR IN THE WAKE
OF THU COLD FROPA AND AHEAD OF SFC HI PRES NEAR LK WINNIPEG. SINCE
THE 00Z INL RAOB SHOWED A VERY DRY...INVERTED V PROFILE AND RECENT
SFC OBS INDICATE FAIRLY LARGE SFC T/TD SPREADS...SKIES ARE MOCLR
OVER UPR MI AS OF 06Z. BUT THE 00Z YPL RAOB DEPICTED A SOMEWHAT
MOISTER...BUT STILL WELL MIXED...SFC-H85 T/TD PROFILE WITH AN H85
TEMP DOWN TO -16C. FARTHER UPSTREAM...A SHRTWV IS MOVING INTO THE
PAC NW. WAD MID/HI CLDS WELL E OF THIS DISTURBANCE ARE SPREADING
INTO THE NRN PLAINS.
TODAY...ALTHOUGH SKIES ARE MOCLR EARLY THIS MRNG...SUSPECT SOME LK
CLDS/EVEN SOME -SHSN MIGHT DVLP OVER AREAS E OF MQT AS THE
MOISTER...COLDER AIRMASS SHOWN ON THE 00Z YPL RAOB WITH H85 TEMPS AS
LO AS -15C IMPACT THIS PART OF THE CWA. OVER THE W HALF...THE VERY
DRY 00Z INL RAOB IS MORE REPRESENTATIVE OF THE SOURCE AIRMASS. SO
REMOVED POPS/DIMINISHED FCST CLDS IN THIS AREA. BUT EVEN OVER THE
E...GENERALY ACYC NATURE OF THE FCST LLVL FLOW AS WELL AS HIER SFC
T/TD DEPRESSIONS EVEN FARTHER E N OF LK SUP SUG ANY SN ACCUMS WL BE
NEGLIGIBLE IF SHSN DO FORM AT ALL. WITH DAYTIME HEATING/LARGE SCALE
SUBSIDENCE AS SFC HI BLDS OVER THE W HALF OF THE CWA BY 18Z...EXPECT
ANY LES OVER THE E TO DIMINISH BY NOON. DIURNAL CU/SC THAT DVLP WITH
DAYTIME HEATING/MIXING UNDER LINGERING H85 THERMAL TROF WL TEND TO
DIMINISH OVER AT LEAST THE W AND CENTRAL WITH MORE EMPHATIC DRYING/
QUICKER TRANSITION TO MORE ACYC FLOW...BUT SC MAY LINGER LONGER OVER
THE E WHERE THE H85 TEMPS WARM ABV -10C ONLY TOWARD 00Z. MIXING TO
H85 AS OBSVD ON UPSTREAM 00Z RAOBS YIELDS HI TEMPS IN THE UPR 30S/
LO 40S OVER THE W...BUT ONLY 30 TO 35 OVER THE CNTRL AND E WHERE
LOWER H85 TEMPS LINGER LONGER. WITH WEAKER PRES GRADIENT ARRIVING
WITH SFC HI CENTER...LK BREEZES WL MAINTAIN LOCAL COOLING NEAR THE
SHORES. SOME HI CLDS WL ARRIVE OVER THE W IN THE AFTN WELL IN
ADVANCE OF PAC NW SHRTWV MOVING THRU THE NRN ROCKIES.
TNGT...AS SHRTWV MOVES THRU THE NRN PLAINS AND ASSOCIATED SFC LO
SHIFTS TO SW MN BY 12Z SAT...EXPECT THICKENING CLDS IN THE DVLPG WAD
PATTERN BTWN THE DEPARTING HI AND INCOMING LO PRES. VIGOROUS
ISENTROPIC ASCENT SHOWN ON THE 280-295K ISENTROPIC SFCS IS FCST TO
SPREAD W-E ACRS THE CWA AND SLOWLY SATURATE THE VERY DRY ANTECEDENT
LO-MID LVLS. FAVOR THE SOMEWHAT SLOWER 00Z NAM/CNDN AND 12Z ECMWF
FOR TIMING LEADING EDGE OF PCPN TIED TO H5-7 FGEN AXIS OVER THE
GFS...WHICH APPEARS TO GENERATE PCPN TOO DEEP INTO THE LINGERING DRY
AIR. THESE FAVORED MODELS INDICATE PCPN WL REACH A LINE FROM
MUNISING-MANISTIQUE BY 12Z SAT... SO RESTRICTED CATEGORICAL POPS TO
THE W OF THAT AXIS. FAVORED MODEL QPF INDICATES 2 TO 3 INCHES OF SN
OVER THE SW CWA BY 12Z SAT EVEN THOUGH RATHER NARROW/HI DGZ CENTERED
ARND 15K FT WL LIMIT SN/WATER RATIOS. EXPECT THE LOWEST MIN TEMPS
OVER THE INTERIOR E...WHERE THE CLDS WL ARRIVE LATEST AND WINDS BE
LGT IN THE EVNG TO ALLOW FOR GOOD RADIATIONAL COOLING. FOLLOWED A
NON-DIURNAL CURVE WITH TEMPS FALLING TO THE LOWEST LVL FAIRLY
EARLY...THEN STEADY OR SLOWLY RISING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 622 AM EDT FRI APR 5 2013
MAIN FCST CONCERNS FOCUS ON SYSTEM FOR SATURDAY...PTYPE
CONCERNS...POSSIBLE HEADLINES AND SNOW AMTS.
ACTIVE SHORTWAVE NOW MOVING IN OFF THE PACIFIC NW AS NOTED ON WATER
VAPOR LOOP IS EXPECTED TO TRACK DUE E...REACHING THE WRN GREAT LAKES
SAT. WHILE MODELS HAVE COME INTO BETTER AGREEMENT WITH TRACK/TIMING
OF SHORTWAVE AND ASSOC SFC LOW SOME IMPORTANT MODEL DIFFERENCES
REMAIN IN THERMAL FIELDS. CONFIDENCE IS HIGH THAT ALL OF THE FCST
AREA WILL SEE PCPN...SO HIGH CATEGORICAL POPS WILL BE PAINTED ACROSS
THE CWA. RIGHT ENTRANCE OF UPPER JET ASSOCIATED WITH ERN CANADA TROF
WILL PROVIDE LARGER SCALE ENHANCEMENT TO UPWARD MOTION...AS A FAIRLY
VIGOROUS FRONTOGENESIS SIGNATURE WILL AID PCPN INTENSITY ON THE
SMALLER SCALE. IT APPEARS THAT THERE MAY BE 2 PERIODS OF FGEN
FORCING...ONE INITIALLY LATE TONIGHT/SAT MORNING THAT
TRANSLATES ACROSS THE AREA...THEN A SECOND SAT AFTN/EVENING THAT
WOULD FAVOR CNTRL/ERN UPPER MI FOR HEAVIER PCPN. WITH MIXING RATIOS
OF 4-5G/KG AND CLOSE TO 12HRS OF ASCENT...THERE COULD BE 6 TO
POSSIBLY AS MUCH AS LOCALLY 8-10 INCHES OF HVY/WET SNOW ALONG THE
AXIS OF HEAVIEST PCPN WHERE PTYPE IS ALL SNOW. SO...DETERMINING THE
CONFIGURATION OF PTYPES WILL BE CRITICAL. IS STILL APPEARS THAT
PTYPE WILL BE ALL SNOW ACROSS THE FCST AREA AS PCPN DEVELOPS TONIGHT
...AND THAT SNOW MAY FALL LONG ENOUGH SO THAT A FEW INCHES OF SNOW
ACCUMULATE EVEN IN AREAS THAT SEE A MIX OR CHANGE TO RAIN DURING THE
DAY SAT. DURING THE DAY SAT...UNCERTAINTY GROWS IN HOW FAR N WARMING
OCCURS. THE 06Z GFS AND NAM BRINGS 0C 850MB ISOTHERM AND CRITICAL
1000-850MB THICKNESS FAR ENOUGH N SO THAT PERHAPS ONLY WEST AND NW
UPPER MI REMAINS MOSTLY SNOW SAT AFTN/EVENING. THE LOCAL WRF-ARW AND
REG-GEM ARE FARTHER S WITH THESE TEMP PARAMETERS AND ARE GENERALLY
MORE IN LINE WITH THE ECMWF...SUGGESTING MUCH OF NRN UPPER MI WILL
STAY MOSTLY SNOW. FCST SOUNDINGS STILL SUGGEST THAT A NARROW ZONE OF
SLEET IS ALSO POSSIBLE IN THE TRANSITION ZONE BTWN MOSTLY SNOW NORTH
TO MOSTLY RAIN SOUTH ON SAT. CONSIDERED ISSUING A WATCH FOR SOME THE
NRN COUNTIES IN SWATH OF EXPECTED HEAVIER PCPN WHERE PTYPE WILL BE
MOSTLY SNOW...BUT GIVEN CONTINUED UNCERTAINTIES WITH PTYPE AND
ULTIMATE ACCUMS DECIDED TO KEEP AN SPS GOING HIGHLIGHTING THE
POTENTIAL FOR VERY HVY/WET SNOW THAT WILL BE DIFFICULT TO
SHOVEL/PLOW AND WILL LEAD TO VERY DIFFICULT TRAVEL CONDITIONS.
ON SUN...SFC HIGH PRES WILL NOSE INTO THE UPPER LAKES BEHIND
SYSTEM...BRINGING AN INFLUX OF DRIER AIR. DAYTIME TEMPS SHOULD
RECOVER WELL INTO THE 30S/LWR 40S IN THE AFTN WITH SOME INCREASE IN
SUNSHINE DURING THE DAY.
FCST FOR MON THRU THU REMAINS UNCERTAIN. MUCH OF THE FCST WILL HINGE
ON THE STRENGTH OF THE LINGERING ERN CANADA TROF UNDER THE WEAKENING
NEGATIVE AO/NAO PATTERN. OTHER THAN A SHOWING A WEAK NRN PLAINS
SHORTWAVE MOVING THROUGH THE AREA LATE SUNDAY NIGHT INTO
MONDAY...THE LATEST ECMWF IS SIMILAR TO RECENT RUNS SHOWING A
STRONGER AND MORE PERSISTENT ERN CANADIAN TROF WHICH KEEPS A DRIER
WNW FLOW ACROSS THE UPPER LAKES FOR THE EARLY PART OF NEXT WEEK.
THIS IDEA ALSO WOULD GO ALONG WITH THE GENERAL PERSISTENT PATTERN
WHICH HAS DOMINATED THE REGION FOR THE LAST SEVERAL WEEKS...ALTHOUGH
IT REMAINS TO BE SEEN HOW LONG PATTERN WILL PERSIST GIVEN EXPECT
WEAKENING OF HIGH LATITUDE BLOCKING. THE 12Z ECMWF DOES FINALLY
BRING PCPN INTO THE FCST AREA ON WED NIGHT AND THU...MAINLY IN FORM
OF SNOW...AS MAIN PIECE OF ENERGY FROM WRN CONUS TROF EJECTS NE
TOWARD THE GREAT LAKES. MEANWHILE...THE LATEST 00Z RUN OF THE GFS
QUICKLY WEAKENS THE ERN CANADIAN TROF AND PUSHES IT EAST ALLOWING
FOR A STRONG SRN STREAM SHORTWAVE TO EJECT TOWARD THE UPPER GREAT
LAKES FM BASE OF WRN CONUS TROF. THE GFS SHOWS 8H TEMPS RISING TO
10-12C BY TUE NIGHT INTO WED ACCOMPANIED BY A SLUG OF GULF MOISTURE
(250-300 PCT OF NORMAL PWAT VALUES) WHICH WOULD YIELD A THREAT OF
MODERATE TO HEAVY RAIN TO THE FCST AREA TUE NIGHT INTO WED. THE 12Z
GEM-NH GENERALLY LENDS MORE SUPPORT TO ECMWF SOLN ALTHOUGH IT ALSO
TENDS TO BREAK DOWN ERN CANADIAN TROF QUICKER THAN ECMWF. GIVEN
CONSIDERABLE MODEL UNCERTAINTY...WILL CONTINUE SIMPLE CONSENSUS
APPROACH TO FCST KEEPING ONLY SCHC POPS FOR MON INTO TUE THEN
INCREASE POPS TO 30-40 PCT CHC FOR WED AND THU WITH THE IDEA THAT
ERN CANADA TROF WILL WEAKEN ALLOWING FOR MORE ENERGY FROM WRN CONUS
TROF TO REACH UPPER GREAT LAKES. TEMPS SHOULD REMAIN BLO NORMAL THRU
THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 135 PM EDT FRI APR 5 2013
HIGH PRESSURE MOVING OVER THE AREA THIS AFTERNOON AND EVENING SHOULD
KEEP VFR CONDITIONS AT EACH TAF SITE. LATE TONIGHT THROUGH SATURDAY
A LOW PRESSURE SYSTEM OVER THE NORTHERN PLAINS WILL SHIFT EASTWARD
INTO THE AREA INTRODUCING A CHANCE OF SNOW TO ALL TAF SITE AS WELL
AS A MIXTURE OF SLEET AT THE IWD TAF SITE. THE BETTER MOISTURE AND
LIFT WILL MOVE INTO THE IWD SITE AROUND 06Z TONIGHT...REACHING THE
SAW SITE BY 10Z. AS THE BETTER LIFT/MOISTURE PASSES OVER THE TAF
SITES EXPECT SNOW TO INTENSIFY EFFECTIVELY REDUCING VISIBILITY TO
IFR CONDITIONS. IT WOULD NOT BE OUT OF THE QUESTION FOR VISIBILITY TO
FALL BELOW 2SM OVERNIGHT AND SATURDAY WITHIN THE HEAVIER SNOW BANDS.
RAISED VISIBILITY AT THE IWD TAF SITE FROM EARLIER THINKING AS SLEET
MAY HELP TO KEEP VISIBILITY A BIT HIGHER. HIGH CLOUDS WILL START TO
STREAM IN THIS AFTERNOON BEFORE DEEPER MOISTURE MOVES IN OVERNIGHT
REDUCING CEILING HEIGHTS TO 1500FT OR LOWER THROUGH THE DAY SATURDAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 622 AM EDT FRI APR 5 2013
NW WINDS UP TO 25 KTS EARLY THIS MORNING OVER THE E HALF WILL
DIMINISH STEADILY TODAY AS HI PRES IS FORECAST TO BUILD OVER UPR MI
BY THIS AFTERNOON. LIGHT WINDS WILL SHIFT TO THE ESE AND INCREASE UP
TO 20 KTS TONIGHT AS THE NEXT LO PRES SYSTEM IS FORECAST TO MOVE TO
SW MN BY SAT MORNING. AS THE PRES GRADIENT TIGHTENS OVER LAKE SUP ON
SAT/SAT NIGHT TO THE N OF THE LO TRACKING THRU THE CENTRAL LAKES...
E-SE BACKING NE WINDS WILL INCREASE UP TO 25 TO 30 KTS BEFORE
DIMINISHING AND FURTHER BACKING TO THE N ON SUN AS TRAILING HI PRES
SHIFTS TOWARD THE UPPER LAKES. FOR EARLY NEXT WEEK...PLAN ON NE
WINDS UP TO 20 KTS ON THE SE FLANK OF HI PRES OVER CENTRAL CANADA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...KEC
MARINE...KC
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1255 PM EDT FRI APR 5 2013
.UPDATE...
ISSUED AT 1254 PM EDT FRI APR 5 2013
GIVEN LARGER SPRING STORM IS QUICKLY ON THE APPROACH...THOUGHT
IT WOULD BE GOOD TO PROVIDE UPDATE IN TERMS OF EXPECTED STORM
INTENSITY/PTYPE AND HEADLINES.
SFC TROUGH THAT EVENTUALLY WILL DEVELOP INTO CLOSED OFF LOW OVER
WESTERN LAKES LATER SATURDAY IS CURRENTLY ALLIGNED FROM SOUTHERN
PORTIONS OF ALBERTA AND SASKATCHEWAN INTO NORTHERN US ROCKIES. 12Z
RAOBS AND WV LOOP SHOW H5 TROUGH PUSHING OUT OF WA/OR...WHILE TROUGH
AT H85 AND H7 IS CLOSER TO THE MAIN SFC LOW. SNOW IS AS CLOSE AS
ND/SASKATCHEAN BORDER ON EDGE OF H8-H7 FRONTOGENESIS. NAM/GFS AND
REGIONAL GEM INITIALIZED LARGER SCALE FEATURES WELL BUT DIFFER ON
CRITICAL THERMAL DETAILS FOR SATURDAY.
OVERALL...AT THE LEAST...WINTER WEATHER ADVISORIES WILL BE POSTED
LATER THIS AFTN FOR ALL OF CWA. ALREADY COORD WITH DLH AND GRB WHICH
HAVE ADVYS UP AND ALSO WITH APX. SOME AREAS MAY NEED WARNINGS BUT IT
WILL DEPEND ON WHERE PTYPE REMAINS MOSTLY SNOW FOR THE EVENT.
UNFORTUNATELY...THIS IS NOT CLEAR CUT EVEN WITHIN 24 HRS AS SOME
MODELS /GFS AND UKMET/ ARE PRETTY WARM AT H85-H8 DURING THE AFTN
HOURS ON SATURDAY /UP TO +3C AT H85/ WHILE NAM/REGIONAL GEM AND 00Z
ECMWF ARE NOT AS WARM. THIS IS ESPECIALLY TOUGH CONSIDERING THEY ARE
FAIRLY SIMILAR WITH H85/H7/H5 FEATURES. AS WOULD BE EXPECTED WITH
THERMAL PROFILES...GFS/SREF ARE SLIGHTLY FARTHER NORTH WITH SFC LOW.
GIVEN STEEP LAPSE RATES IN MID-LEVELS FEEDING INTO AREA OF
PRECIPITATION OVER UPR MICHIGAN...THERE IS ALSO CONCERN CONVECTION
WILL MODULATE INTENSITY AND PTYPE OVER THE CWA.
AT THIS POINT...FAR SOUTH SEEMS PRETTY CERTAIN TO SEE MAINLY RAIN BY
SATURDAY AFTN SO SNOW AMOUNTS WILL ULTIMATELY BE HELD DOWN FROM IMT
TO ESC AND CERTAINLY SOUTH TO MNM. GOGEBIC AND IRON TOUGH CALL AS
INITIAL WARM NOSE MAY RESULT IN MIX OF SLEET/SNOW AND EVEN RAIN LATE
TONIGHT INTO SATURDAY MORNING BUT PRECIP WOULD TURN BACK TO MAINLY
SNOW ON SATURDAY AFTN AS H7-H5 TROUGH/PRIMARY SHORTWAVES/LARGER
SCALE LIFTING AND DYNAMIC COOLING ARRIVE. MUCH MORE OF A QUESTION
IN THE TIER OF COUNTIES NORTH...FROM ONTONAGON/SOUTHERN HOUGHTON
THROUGH BARARA/MARQUETTE AND EAST TO ALGER/SCHOOLCRAFT/LUCE COUNTY.
IN THESE AREAS INITIAL SHOT OF PRECIP SATURDAY MORNING SHOULD REMAIN
MOSTLY SNOW AS THINK THAT DYNAMIC COOLING TIED TO STRONG H8-H5 FGEN
OFFSETS SHALLOW WARM LAYER H85-H8 AROUND +1C. INITIAL SURGE OF
PRECIP DRIVEN BY 295-305K /H85-H5/ ISENTROPIC ASCENT AND DIVERGENCE
ALOFT FROM LARGE JET STREAK OVER ONTARIO INTO QUEBEC COULD END AS
MIX OF SLEET/SNOW AS DYNAMIC COOLING FADES BTWN 15Z-18Z. STILL MANY
DETAILS TO BE SORTED OUT BUT WINTER WEATHER STATEMENT WITH FINAL
HEADLINE DECISIONS WILL BE OUT LATER THIS AFTN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 622 AM EDT FRI APR 5 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CONFLUENT NW FLOW
ALF OVER THE GRT LKS DOWNSTREAM OF RDG OVER THE ROCKIES. AT THE
LLVLS...THE CWA IS DOMINATING BY A NW FLOW OF COLDER AIR IN THE WAKE
OF THU COLD FROPA AND AHEAD OF SFC HI PRES NEAR LK WINNIPEG. SINCE
THE 00Z INL RAOB SHOWED A VERY DRY...INVERTED V PROFILE AND RECENT
SFC OBS INDICATE FAIRLY LARGE SFC T/TD SPREADS...SKIES ARE MOCLR
OVER UPR MI AS OF 06Z. BUT THE 00Z YPL RAOB DEPICTED A SOMEWHAT
MOISTER...BUT STILL WELL MIXED...SFC-H85 T/TD PROFILE WITH AN H85
TEMP DOWN TO -16C. FARTHER UPSTREAM...A SHRTWV IS MOVING INTO THE
PAC NW. WAD MID/HI CLDS WELL E OF THIS DISTURBANCE ARE SPREADING
INTO THE NRN PLAINS.
TODAY...ALTHOUGH SKIES ARE MOCLR EARLY THIS MRNG...SUSPECT SOME LK
CLDS/EVEN SOME -SHSN MIGHT DVLP OVER AREAS E OF MQT AS THE
MOISTER...COLDER AIRMASS SHOWN ON THE 00Z YPL RAOB WITH H85 TEMPS AS
LO AS -15C IMPACT THIS PART OF THE CWA. OVER THE W HALF...THE VERY
DRY 00Z INL RAOB IS MORE REPRESENTATIVE OF THE SOURCE AIRMASS. SO
REMOVED POPS/DIMINISHED FCST CLDS IN THIS AREA. BUT EVEN OVER THE
E...GENERALY ACYC NATURE OF THE FCST LLVL FLOW AS WELL AS HIER SFC
T/TD DEPRESSIONS EVEN FARTHER E N OF LK SUP SUG ANY SN ACCUMS WL BE
NEGLIGIBLE IF SHSN DO FORM AT ALL. WITH DAYTIME HEATING/LARGE SCALE
SUBSIDENCE AS SFC HI BLDS OVER THE W HALF OF THE CWA BY 18Z...EXPECT
ANY LES OVER THE E TO DIMINISH BY NOON. DIURNAL CU/SC THAT DVLP WITH
DAYTIME HEATING/MIXING UNDER LINGERING H85 THERMAL TROF WL TEND TO
DIMINISH OVER AT LEAST THE W AND CENTRAL WITH MORE EMPHATIC DRYING/
QUICKER TRANSITION TO MORE ACYC FLOW...BUT SC MAY LINGER LONGER OVER
THE E WHERE THE H85 TEMPS WARM ABV -10C ONLY TOWARD 00Z. MIXING TO
H85 AS OBSVD ON UPSTREAM 00Z RAOBS YIELDS HI TEMPS IN THE UPR 30S/
LO 40S OVER THE W...BUT ONLY 30 TO 35 OVER THE CNTRL AND E WHERE
LOWER H85 TEMPS LINGER LONGER. WITH WEAKER PRES GRADIENT ARRIVING
WITH SFC HI CENTER...LK BREEZES WL MAINTAIN LOCAL COOLING NEAR THE
SHORES. SOME HI CLDS WL ARRIVE OVER THE W IN THE AFTN WELL IN
ADVANCE OF PAC NW SHRTWV MOVING THRU THE NRN ROCKIES.
TNGT...AS SHRTWV MOVES THRU THE NRN PLAINS AND ASSOCIATED SFC LO
SHIFTS TO SW MN BY 12Z SAT...EXPECT THICKENING CLDS IN THE DVLPG WAD
PATTERN BTWN THE DEPARTING HI AND INCOMING LO PRES. VIGOROUS
ISENTROPIC ASCENT SHOWN ON THE 280-295K ISENTROPIC SFCS IS FCST TO
SPREAD W-E ACRS THE CWA AND SLOWLY SATURATE THE VERY DRY ANTECEDENT
LO-MID LVLS. FAVOR THE SOMEWHAT SLOWER 00Z NAM/CNDN AND 12Z ECMWF
FOR TIMING LEADING EDGE OF PCPN TIED TO H5-7 FGEN AXIS OVER THE
GFS...WHICH APPEARS TO GENERATE PCPN TOO DEEP INTO THE LINGERING DRY
AIR. THESE FAVORED MODELS INDICATE PCPN WL REACH A LINE FROM
MUNISING-MANISTIQUE BY 12Z SAT... SO RESTRICTED CATEGORICAL POPS TO
THE W OF THAT AXIS. FAVORED MODEL QPF INDICATES 2 TO 3 INCHES OF SN
OVER THE SW CWA BY 12Z SAT EVEN THOUGH RATHER NARROW/HI DGZ CENTERED
ARND 15K FT WL LIMIT SN/WATER RATIOS. EXPECT THE LOWEST MIN TEMPS
OVER THE INTERIOR E...WHERE THE CLDS WL ARRIVE LATEST AND WINDS BE
LGT IN THE EVNG TO ALLOW FOR GOOD RADIATIONAL COOLING. FOLLOWED A
NON-DIURNAL CURVE WITH TEMPS FALLING TO THE LOWEST LVL FAIRLY
EARLY...THEN STEADY OR SLOWLY RISING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 622 AM EDT FRI APR 5 2013
MAIN FCST CONCERNS FOCUS ON SYSTEM FOR SATURDAY...PTYPE
CONCERNS...POSSIBLE HEADLINES AND SNOW AMTS.
ACTIVE SHORTWAVE NOW MOVING IN OFF THE PACIFIC NW AS NOTED ON WATER
VAPOR LOOP IS EXPECTED TO TRACK DUE E...REACHING THE WRN GREAT LAKES
SAT. WHILE MODELS HAVE COME INTO BETTER AGREEMENT WITH TRACK/TIMING
OF SHORTWAVE AND ASSOC SFC LOW SOME IMPORTANT MODEL DIFFERENCES
REMAIN IN THERMAL FIELDS. CONFIDENCE IS HIGH THAT ALL OF THE FCST
AREA WILL SEE PCPN...SO HIGH CATEGORICAL POPS WILL BE PAINTED ACROSS
THE CWA. RIGHT ENTRANCE OF UPPER JET ASSOCIATED WITH ERN CANADA TROF
WILL PROVIDE LARGER SCALE ENHANCEMENT TO UPWARD MOTION...AS A FAIRLY
VIGOROUS FRONTOGENESIS SIGNATURE WILL AID PCPN INTENSITY ON THE
SMALLER SCALE. IT APPEARS THAT THERE MAY BE 2 PERIODS OF FGEN
FORCING...ONE INITIALLY LATE TONIGHT/SAT MORNING THAT
TRANSLATES ACROSS THE AREA...THEN A SECOND SAT AFTN/EVENING THAT
WOULD FAVOR CNTRL/ERN UPPER MI FOR HEAVIER PCPN. WITH MIXING RATIOS
OF 4-5G/KG AND CLOSE TO 12HRS OF ASCENT...THERE COULD BE 6 TO
POSSIBLY AS MUCH AS LOCALLY 8-10 INCHES OF HVY/WET SNOW ALONG THE
AXIS OF HEAVIEST PCPN WHERE PTYPE IS ALL SNOW. SO...DETERMINING THE
CONFIGURATION OF PTYPES WILL BE CRITICAL. IS STILL APPEARS THAT
PTYPE WILL BE ALL SNOW ACROSS THE FCST AREA AS PCPN DEVELOPS TONIGHT
...AND THAT SNOW MAY FALL LONG ENOUGH SO THAT A FEW INCHES OF SNOW
ACCUMULATE EVEN IN AREAS THAT SEE A MIX OR CHANGE TO RAIN DURING THE
DAY SAT. DURING THE DAY SAT...UNCERTAINTY GROWS IN HOW FAR N WARMING
OCCURS. THE 06Z GFS AND NAM BRINGS 0C 850MB ISOTHERM AND CRITICAL
1000-850MB THICKNESS FAR ENOUGH N SO THAT PERHAPS ONLY WEST AND NW
UPPER MI REMAINS MOSTLY SNOW SAT AFTN/EVENING. THE LOCAL WRF-ARW AND
REG-GEM ARE FARTHER S WITH THESE TEMP PARAMETERS AND ARE GENERALLY
MORE IN LINE WITH THE ECMWF...SUGGESTING MUCH OF NRN UPPER MI WILL
STAY MOSTLY SNOW. FCST SOUNDINGS STILL SUGGEST THAT A NARROW ZONE OF
SLEET IS ALSO POSSIBLE IN THE TRANSITION ZONE BTWN MOSTLY SNOW NORTH
TO MOSTLY RAIN SOUTH ON SAT. CONSIDERED ISSUING A WATCH FOR SOME THE
NRN COUNTIES IN SWATH OF EXPECTED HEAVIER PCPN WHERE PTYPE WILL BE
MOSTLY SNOW...BUT GIVEN CONTINUED UNCERTAINTIES WITH PTYPE AND
ULTIMATE ACCUMS DECIDED TO KEEP AN SPS GOING HIGHLIGHTING THE
POTENTIAL FOR VERY HVY/WET SNOW THAT WILL BE DIFFICULT TO
SHOVEL/PLOW AND WILL LEAD TO VERY DIFFICULT TRAVEL CONDITIONS.
ON SUN...SFC HIGH PRES WILL NOSE INTO THE UPPER LAKES BEHIND
SYSTEM...BRINGING AN INFLUX OF DRIER AIR. DAYTIME TEMPS SHOULD
RECOVER WELL INTO THE 30S/LWR 40S IN THE AFTN WITH SOME INCREASE IN
SUNSHINE DURING THE DAY.
FCST FOR MON THRU THU REMAINS UNCERTAIN. MUCH OF THE FCST WILL HINGE
ON THE STRENGTH OF THE LINGERING ERN CANADA TROF UNDER THE WEAKENING
NEGATIVE AO/NAO PATTERN. OTHER THAN A SHOWING A WEAK NRN PLAINS
SHORTWAVE MOVING THROUGH THE AREA LATE SUNDAY NIGHT INTO
MONDAY...THE LATEST ECMWF IS SIMILAR TO RECENT RUNS SHOWING A
STRONGER AND MORE PERSISTENT ERN CANADIAN TROF WHICH KEEPS A DRIER
WNW FLOW ACROSS THE UPPER LAKES FOR THE EARLY PART OF NEXT WEEK.
THIS IDEA ALSO WOULD GO ALONG WITH THE GENERAL PERSISTENT PATTERN
WHICH HAS DOMINATED THE REGION FOR THE LAST SEVERAL WEEKS...ALTHOUGH
IT REMAINS TO BE SEEN HOW LONG PATTERN WILL PERSIST GIVEN EXPECT
WEAKENING OF HIGH LATITUDE BLOCKING. THE 12Z ECMWF DOES FINALLY
BRING PCPN INTO THE FCST AREA ON WED NIGHT AND THU...MAINLY IN FORM
OF SNOW...AS MAIN PIECE OF ENERGY FROM WRN CONUS TROF EJECTS NE
TOWARD THE GREAT LAKES. MEANWHILE...THE LATEST 00Z RUN OF THE GFS
QUICKLY WEAKENS THE ERN CANADIAN TROF AND PUSHES IT EAST ALLOWING
FOR A STRONG SRN STREAM SHORTWAVE TO EJECT TOWARD THE UPPER GREAT
LAKES FM BASE OF WRN CONUS TROF. THE GFS SHOWS 8H TEMPS RISING TO
10-12C BY TUE NIGHT INTO WED ACCOMPANIED BY A SLUG OF GULF MOISTURE
(250-300 PCT OF NORMAL PWAT VALUES) WHICH WOULD YIELD A THREAT OF
MODERATE TO HEAVY RAIN TO THE FCST AREA TUE NIGHT INTO WED. THE 12Z
GEM-NH GENERALLY LENDS MORE SUPPORT TO ECMWF SOLN ALTHOUGH IT ALSO
TENDS TO BREAK DOWN ERN CANADIAN TROF QUICKER THAN ECMWF. GIVEN
CONSIDERABLE MODEL UNCERTAINTY...WILL CONTINUE SIMPLE CONSENSUS
APPROACH TO FCST KEEPING ONLY SCHC POPS FOR MON INTO TUE THEN
INCREASE POPS TO 30-40 PCT CHC FOR WED AND THU WITH THE IDEA THAT
ERN CANADA TROF WILL WEAKEN ALLOWING FOR MORE ENERGY FROM WRN CONUS
TROF TO REACH UPPER GREAT LAKES. TEMPS SHOULD REMAIN BLO NORMAL THRU
THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 732 AM EDT FRI APR 5 2013
ALTHOUGH THERE WL BE SOME SC AT MAINLY SAW INTO THIS AFTN...DRY
NATURE OF THE INCOMING AIRMASS ASSOCIATED WITH HI PRES MOVING INTO
MN WL BRING VFR CONDITIONS AT ALL 3 LOCATIONS INTO THIS EVNG.
THICKER CLDS AND THEN SN WL ARRIVE TNGT IN ADVANCE OF A LO PRES
SYSTEM MOVING THRU THE NRN PLAINS. EVEN BEFORE THE SN ARRIVES...CIGS
AT SAW MAY FALL INTO THE MVFR RANGE WITH UPSLOPE SE FLOW BTWN THE
DEPARTING HI/INCOMING LO PRES. EXPECT VSBYS TO DROP INTO THE IFR
CATEGORY AT ALL 3 LOCATIONS AFTER MIDNGT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 622 AM EDT FRI APR 5 2013
NW WINDS UP TO 25 KTS EARLY THIS MORNING OVER THE E HALF WILL
DIMINISH STEADILY TODAY AS HI PRES IS FORECAST TO BUILD OVER UPR MI
BY THIS AFTERNOON. LIGHT WINDS WILL SHIFT TO THE ESE AND INCREASE UP
TO 20 KTS TONIGHT AS THE NEXT LO PRES SYSTEM IS FORECAST TO MOVE TO
SW MN BY SAT MORNING. AS THE PRES GRADIENT TIGHTENS OVER LAKE SUP ON
SAT/SAT NIGHT TO THE N OF THE LO TRACKING THRU THE CENTRAL LAKES...
E-SE BACKING NE WINDS WILL INCREASE UP TO 25 TO 30 KTS BEFORE
DIMINISHING AND FURTHER BACKING TO THE N ON SUN AS TRAILING HI PRES
SHIFTS TOWARD THE UPPER LAKES. FOR EARLY NEXT WEEK...PLAN ON NE
WINDS UP TO 20 KTS ON THE SE FLANK OF HI PRES OVER CENTRAL CANADA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1230 PM CDT FRI APR 5 2013
.UPDATE...
ISSUED AT 1116 AM CDT FRI APR 5 2013
AREAS OF CLOUD COVER HAVE THUS FAR LIMITED THE RISE IN
TEMPERATURES THIS MORNING. WENT AHEAD AND UPDATED THE FORECAST
TO LOWER MAX T/S A COUPLE DEGREES ACROSS THE BOARD. OTHERWISE NO
CHANGES TO OUR CURRENT RED FLAG WARNING...EVEN WITH THE SLIGHTLY
COOLER TEMPERATURES...STILL LOOKING AT WIDESPREAD SUB 20 PERCENT
RH ACROSS FIRE ZONES 204 AND 210...WITH LOCALIZED AREAS OF 15
PERCENT. CRITICAL WIND SPEEDS ARE NOT THERE YET...BUT STILL
ANTICIPATING GUSTS AOA 25 MPH DURING PEAK HEATING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT FRI APR 5 2013
A MODIFIED ARCTIC FRONT IS LINED UP FROM ROUGHLY KFNB TO KLBF TO
E-KIEN. THE FRONT WILL LIFT NORTH TODAY AS LOW
PRESSURE...CURRENTLY ACROSS NERN WY...MOVES EAST THROUGH SRN SD.
THE TEMPERATURE FCST USES 50 PERCENT OF THE RAP13 AND A BLEND OF
OTHER MODELS. THE RAP IS VERY WARM BUT GIVEN THE CLOUDS MOVING
IN...IT IS PROBABLY TOO WARM.
THE NAM RADAR AND THUNDERSTORM PRODUCTS SUGGEST ISOLATED HIGH
BASED SHRA AND TSTM THIS AFTN AND THIS EVENING. LITTLE OR NO
RAINFALL IS EXPECTED. AS THE SFC LOW TRACKS THROUGH SD TODAY AND
INTO SRN MN TONIGHT...A PACIFIC COLD FRONT WILL DROP THROUGH THE
FCST AREA. THIS WILL KEEP LOWS ON THE WARM SIDE WITH LOWS MAINLY
IN THE 40S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 356 AM CDT FRI APR 5 2013
SATURDAY WILL STILL BE ANOTHER MILD DAY AS MOSTLY SUNNY SKIES
BEHIND THE PACIFIC COLD FRONT PREVAIL. HIGHS SHOULD PUSH IN THE
60S WHICH IS DOWN ABOUT 10 TO 15 DEGREES FROM FRIDAY...BUT STILL
ABOVE NORMAL. SATURDAY NIGHT A TROUGH DEVELOPS ALONG THE FRONT
RANGE AND WILL BRING A SLIGHT CHANCE FOR SHOWERS TO THE EASTERN
PANHANDLE. MOISTURE IS LIMITED AND WILL HAVE TO OVERCOME A DRY
LOWER LAYER THUS EXPECT AMOUNTS LIGHT.
SUNDAY WILL SEE THE NEXT WAVE PUSH ONTO THE HIGH PLAINS. MOISTURE
IS LIMITED WITH PRECIP WATER ONLY AROUND 75 PERCENT OF
NORMAL...FOR APRIL. INSTABILITY INCREASES DURING THE AFTERNOON
WITH HEATING...AND SHOULD BE ENOUGH TO SET OFF SOME THUNDERSTORMS.
CAPE VALUES ONLY A FEW HUNDRED J/KG...HOWEVER GREATER VALUES NOT TO
FAR TO THE SOUTH IN KS.
NEXT WEEK WILL SEE A MAJOR LOW DIG TOWARDS THE 4 CORNERS THEN
EJECT ONTO THE PLAINS BY MID WEEK. THE MODELS CONTINUE TO
STRUGGLE ON TIMING AND STRENGTH OF THE SYSTEM...WHICH LEADS TO A
LOWER THAN AVERAGE CONFIDENCE IN FORECAST.
THE GFS CONTINUES TO BE A FASTER SOLUTION...WHILE THE ECMWF BRINGS
UP THE REAR. INITIALLY THINK AS THE LOW PUSHES TOWARDS THE
ROCKIES...SOME MOISTURE WILL ADVECT NORTH. WE MAY GET DRY SLOTTED
SUNDAY NIGHT INTO MONDAY...AHEAD OF THE LOW. HOWEVER PRECIP WATER
INCREASES TO AROUND AN INCH...WHICH IS CLOSER TO 2 SD...LATE
MONDAY. NEG LI/S SHOULD LEAD TO SOME SHOWERS AND THUNDER ACROSS
MOST OF THE AREA.
THEN AS THE UPPER LOW EJECTS ONTO THE PLAINS...WILL SEE SOME COLD
AIR DEVELOP ON THE BACK SIDE. THIS WILL ALSO WORK IN TANDEM WITH
COOL TEMPS AT NIGHT. WILL NEED TO MENTION SOME SN IN THE NW AND A
MIX TO THE SOUTH AND EAST. LATEST MEX GUIDANCE FOR TUES AND WED
HOLD DAYTIME HIGHS IN THE NW IN THE 30S. WHICH IS POSSIBLE AS THE
CLOUDS WILL LIMIT DIURNAL SWING. ANOTHER CONCERN IS THE TIGHT
PRESSURE GRADIENT...WHICH WILL CREATE SOME WINDY CONDITIONS. THE
SYSTEM IS VERY SLOW TO PUSH ACROSS THE PLAINS...WITH IMPACT
THROUGH AT LEAST EARLY WEDNESDAY.
FOR THE LATER PART OF THE WEEK A SECONDARY UPPER LEVEL DISTURBANCE
ROTATES DOWN ACROSS THE WESTERN PLAINS. ALTHOUGH MODELS HAVE HIGH
PRESSURE AT THE SURFACE...THE UPPER LEVEL WAVE SHOULD HAVE ENOUGH
MOISTURE TO STILL PRODUCE CLOUDS AND SOME LIGHT RAIN OR SNOW.
LONG WAY TROUGH FINALLY SHOULD BE EAST BY THURSDAY OR
FRIDAY...WITH A RIDGE TO THE WEST. THIS WILL RESULT IN NW FLOW AND
A TRAIN OF UPPER LEVEL SHORT WAVES. WILL LIKELY NEED TO MENTION AT
LEAST SOME LIGHT PRECIP TOWARDS THE END OF THE WEEK...HOWEVER
TIMING ISSUES ARE COMMON THIS FAR OUT AND WILL NOT BLANKET POPS.
WILL MONITOR AND ADD WHEN CONFIDENCE IS HIGHER ON LOCATION AND
TIMING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1230 PM CDT FRI APR 5 2013
VFR EXPECTED FOR ALL TERMINALS TODAY AND TONIGHT. STILL SEE AN
OPPORTUNITY FOR A STRAY TSTM OR TWO THIS AFTERNOON/EVENING ACROSS
NORTHERN NEBRASKA...BUT OVERALL COVERAGE WILL BE ISOLATED AT BEST.
DUE TO THE DRY LOWER LEVELS OF THE ATMOSPHERE...ERRATIC GUSTY WIND
WOULD ACCOMPANY ANY STORM THAT WERE TO DEVELOP. OTHERWISE A STRONG
PACIFIC COLD FRONT WILL CROSS THE REGION THIS EVENING/OVERNIGHT...A
WIND SHIFT WILL ACCOMPANY THE PASSAGE WITH SFC WINDS VEERING FROM
SOUTHERLY TO NORTHWESTERLY...AND STAYING GUSTY THROUGH MUCH OF THE
FORECAST PERIOD. MODEL GUIDANCE INDICATES THE FRONT THROUGH KVTN
AND KLBF FROM THE 04-06Z TIME FRAME.
&&
.FIRE WEATHER...
ISSUED AT 356 AM CDT FRI APR 5 2013
A WEAKNESS IN THE WIND FIELDS IS SHOWING UP ACROSS SWRN NEB.
THUS...RELATIVE HUMIDITY WILL BE VERY LOW IN THAT AREA BUT WINDS
MAY NOT BE STRONG ENOUGH FOR CRITICAL FIRE DANGER. STRONGER WEST
WINDS SHOW UP ACROSS THE ERN NEB PANHANDLE. THESE WEST WINDS WILL
SWEEP EAST THIS AFTN TO NEAR KVTN AND KTIF. SOUTH WINDS CONTINUE
EAST OF HIGHWAY 83. PRESUMABLY...THIS WILL DRAW MORE MOIST AIR
NORTH FROM KS AND OKLAHOMA.
THE RAP MODEL IS VERY DRY AND SUGGESTS CRITICAL FIRE CONDITIONS
COULD SPREAD THROUGHOUT WESTERN AND NORTH CENTRAL NEB THIS
AFTERNOON. THIS IS AN OCCASIONAL BIAS THAT SHOWS IN THE MODEL BUT
IT SENSES THE DRYNESS OF THE ARCTIC AIR AND INCORPORATES IT INTO
THE AFTN WEATHER. THE MODEL COULD BE CORRECT TO A DEGREE. THE
BEST FORECAST IS A BLEND OF THE RAP WHICH IS VERY DRY AND THE
OTHER MODELS WHICH TEND TO BE TOO MOIST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 8 PM CDT /7 PM MDT/ THIS EVENING FOR
NEZ204-210.
&&
$$
UPDATE...JACOBS
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...JACOBS
FIRE WEATHER...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1116 AM CDT FRI APR 5 2013
.UPDATE...
ISSUED AT 1116 AM CDT FRI APR 5 2013
AREAS OF CLOUD COVER HAVE THUS FAR LIMITED THE RISE IN
TEMPERATURES THIS MORNING. WENT AHEAD AND UPDATED THE FORECAST
TO LOWER MAX T/S A COUPLE DEGREES ACROSS THE BOARD. OTHERWISE NO
CHANGES TO OUR CURRENT RED FLAG WARNING...EVEN WITH THE SLIGHTLY
COOLER TEMPERATURES...STILL LOOKING AT WIDESPREAD SUB 20 PERCENT
RH ACROSS FIRE ZONES 204 AND 210...WITH LOCALIZED AREAS OF 15
PERCENT. CRITICAL WIND SPEEDS ARE NOT THERE YET...BUT STILL
ANTICIPATING GUSTS AOA 25 MPH DURING PEAK HEATING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT FRI APR 5 2013
A MODIFIED ARCTIC FRONT IS LINED UP FROM ROUGHLY KFNB TO KLBF TO
E-KIEN. THE FRONT WILL LIFT NORTH TODAY AS LOW
PRESSURE...CURRENTLY ACROSS NERN WY...MOVES EAST THROUGH SRN SD.
THE TEMPERATURE FCST USES 50 PERCENT OF THE RAP13 AND A BLEND OF
OTHER MODELS. THE RAP IS VERY WARM BUT GIVEN THE CLOUDS MOVING
IN...IT IS PROBABLY TOO WARM.
THE NAM RADAR AND THUNDERSTORM PRODUCTS SUGGEST ISOLATED HIGH
BASED SHRA AND TSTM THIS AFTN AND THIS EVENING. LITTLE OR NO
RAINFALL IS EXPECTED. AS THE SFC LOW TRACKS THROUGH SD TODAY AND
INTO SRN MN TONIGHT...A PACIFIC COLD FRONT WILL DROP THROUGH THE
FCST AREA. THIS WILL KEEP LOWS ON THE WARM SIDE WITH LOWS MAINLY
IN THE 40S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 356 AM CDT FRI APR 5 2013
SATURDAY WILL STILL BE ANOTHER MILD DAY AS MOSTLY SUNNY SKIES
BEHIND THE PACIFIC COLD FRONT PREVAIL. HIGHS SHOULD PUSH IN THE
60S WHICH IS DOWN ABOUT 10 TO 15 DEGREES FROM FRIDAY...BUT STILL
ABOVE NORMAL. SATURDAY NIGHT A TROUGH DEVELOPS ALONG THE FRONT
RANGE AND WILL BRING A SLIGHT CHANCE FOR SHOWERS TO THE EASTERN
PANHANDLE. MOISTURE IS LIMITED AND WILL HAVE TO OVERCOME A DRY
LOWER LAYER THUS EXPECT AMOUNTS LIGHT.
SUNDAY WILL SEE THE NEXT WAVE PUSH ONTO THE HIGH PLAINS. MOISTURE
IS LIMITED WITH PRECIP WATER ONLY AROUND 75 PERCENT OF
NORMAL...FOR APRIL. INSTABILITY INCREASES DURING THE AFTERNOON
WITH HEATING...AND SHOULD BE ENOUGH TO SET OFF SOME THUNDERSTORMS.
CAPE VALUES ONLY A FEW HUNDRED J/KG...HOWEVER GREATER VALUES NOT TO
FAR TO THE SOUTH IN KS.
NEXT WEEK WILL SEE A MAJOR LOW DIG TOWARDS THE 4 CORNERS THEN
EJECT ONTO THE PLAINS BY MID WEEK. THE MODELS CONTINUE TO
STRUGGLE ON TIMING AND STRENGTH OF THE SYSTEM...WHICH LEADS TO A
LOWER THAN AVERAGE CONFIDENCE IN FORECAST.
THE GFS CONTINUES TO BE A FASTER SOLUTION...WHILE THE ECMWF BRINGS
UP THE REAR. INITIALLY THINK AS THE LOW PUSHES TOWARDS THE
ROCKIES...SOME MOISTURE WILL ADVECT NORTH. WE MAY GET DRY SLOTTED
SUNDAY NIGHT INTO MONDAY...AHEAD OF THE LOW. HOWEVER PRECIP WATER
INCREASES TO AROUND AN INCH...WHICH IS CLOSER TO 2 SD...LATE
MONDAY. NEG LI/S SHOULD LEAD TO SOME SHOWERS AND THUNDER ACROSS
MOST OF THE AREA.
THEN AS THE UPPER LOW EJECTS ONTO THE PLAINS...WILL SEE SOME COLD
AIR DEVELOP ON THE BACK SIDE. THIS WILL ALSO WORK IN TANDEM WITH
COOL TEMPS AT NIGHT. WILL NEED TO MENTION SOME SN IN THE NW AND A
MIX TO THE SOUTH AND EAST. LATEST MEX GUIDANCE FOR TUES AND WED
HOLD DAYTIME HIGHS IN THE NW IN THE 30S. WHICH IS POSSIBLE AS THE
CLOUDS WILL LIMIT DIURNAL SWING. ANOTHER CONCERN IS THE TIGHT
PRESSURE GRADIENT...WHICH WILL CREATE SOME WINDY CONDITIONS. THE
SYSTEM IS VERY SLOW TO PUSH ACROSS THE PLAINS...WITH IMPACT
THROUGH AT LEAST EARLY WEDNESDAY.
FOR THE LATER PART OF THE WEEK A SECONDARY UPPER LEVEL DISTURBANCE
ROTATES DOWN ACROSS THE WESTERN PLAINS. ALTHOUGH MODELS HAVE HIGH
PRESSURE AT THE SURFACE...THE UPPER LEVEL WAVE SHOULD HAVE ENOUGH
MOISTURE TO STILL PRODUCE CLOUDS AND SOME LIGHT RAIN OR SNOW.
LONG WAY TROUGH FINALLY SHOULD BE EAST BY THURSDAY OR
FRIDAY...WITH A RIDGE TO THE WEST. THIS WILL RESULT IN NW FLOW AND
A TRAIN OF UPPER LEVEL SHORT WAVES. WILL LIKELY NEED TO MENTION AT
LEAST SOME LIGHT PRECIP TOWARDS THE END OF THE WEEK...HOWEVER
TIMING ISSUES ARE COMMON THIS FAR OUT AND WILL NOT BLANKET POPS.
WILL MONITOR AND ADD WHEN CONFIDENCE IS HIGHER ON LOCATION AND
TIMING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 619 AM CDT FRI APR 5 2013
VFR IS EXPECTED ALL AREAS TODAY AND TONIGHT. ISOLATED AFTERNOON
AND EVENING THUNDERSTORMS ARE POSSIBLE WITH THE APPROACH OF A
STRONG PACIFIC COLD FRONT. THE FRONT IS EXPECTED TO PRODUCE A
PERIOD OF GUSTY WINDS ACROSS NRN NEB TONIGHT. OTHERWISE SCT-BKN120-200
CIGS WILL CONTINUE THROUGH 06Z TONIGHT.
&&
.FIRE WEATHER...
ISSUED AT 356 AM CDT FRI APR 5 2013
A WEAKNESS IN THE WIND FIELDS IS SHOWING UP ACROSS SWRN NEB.
THUS...RELATIVE HUMIDITY WILL BE VERY LOW IN THAT AREA BUT WINDS
MAY NOT BE STRONG ENOUGH FOR CRITICAL FIRE DANGER. STRONGER WEST
WINDS SHOW UP ACROSS THE ERN NEB PANHANDLE. THESE WEST WINDS WILL
SWEEP EAST THIS AFTN TO NEAR KVTN AND KTIF. SOUTH WINDS CONTINUE
EAST OF HIGHWAY 83. PRESUMABLY...THIS WILL DRAW MORE MOIST AIR
NORTH FROM KS AND OKLAHOMA.
THE RAP MODEL IS VERY DRY AND SUGGESTS CRITICAL FIRE CONDITIONS
COULD SPREAD THROUGHOUT WESTERN AND NORTH CENTRAL NEB THIS
AFTERNOON. THIS IS AN OCCASIONAL BIAS THAT SHOWS IN THE MODEL BUT
IT SENSES THE DRYNESS OF THE ARCTIC AIR AND INCORPORATES IT INTO
THE AFTN WEATHER. THE MODEL COULD BE CORRECT TO A DEGREE. THE
BEST FORECAST IS A BLEND OF THE RAP WHICH IS VERY DRY AND THE
OTHER MODELS WHICH TEND TO BE TOO MOIST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 8 PM CDT /7 PM MDT/ THIS EVENING FOR
NEZ204-210.
&&
$$
UPDATE...JACOBS
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...CDC
FIRE WEATHER...CDC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
126 PM EDT FRI APR 5 2013
.SYNOPSIS...
LOW PRESSURE SYSTEM JUST OFF THE NORTH CAROLINA COAST WILL
CONTINUE TO LIFT OFF TO THE NORTHEAST AWAY FROM THE AREA THROUGH
TODAY. HIGH PRESSURE WILL BUILD IN BEHIND THIS STORM SYSTEM...
BRINGING A WARMING TREND AND SPRING-LIKE TEMPERATURES THROUGH NEXT
WEEK. A MORE SUMMER-LIKE PATTERN SETS UP THROUGH MID WEEK AS BERMUDA
HIGH PRESSURE DOMINATES BEFORE A COLD FRONT APPROACHES FROM THE WEST
TOWARD LATE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 12:30 PM FRIDAY...OTHER THAN FOR GEORGETOWN COUNTY THE
LATEST GUIDANCE AND RADAR LOOPS SUGGEST THAT PRECIP HAS ENDED FOR
THE DAY. HAVE ALREADY CUT BACK ON POPS WITH THE LATEST
ISSUANCES...AND WILL LIKELY MAY DROP POPS COMPLETELY WITH THE NEXT
FORECAST PACKAGE. PREVIOUS DISCUSSION FOLLOWS:
AN UPPER LEVEL DISTURBANCE MOVING RAPIDLY NORTH THROUGH GEORGIA
AND NOW SOUTH CAROLINA HAS PRODUCED AN IMPRESSIVE AREA OF SHOWERS
AND THUNDERSTORMS EXTENDING FROM GEORGETOWN SC SOUTH BACK INTO
WAYCROSS AND AMERICUS GA VICINITY. THIS CONVECTION IS ELEVATED
WITH THE LIFTING PARCEL LEVEL PROBABLY IN THE VICINITY OF 10000 FT
AGL OR 700 MB. LATEST RUC ANALYSIS SHOWS LAPSE RATES IN THE
700-500 MB LAYER ARE EXCEEDING 7C/KM...AND FORECAST SOUNDINGS FROM
VIRTUALLY ANY MODEL SHOW STEEP LAPSE RATES CONTINUING FOR AT LEAST
ANOTHER 100 MB HIGHER IN THE ATMOSPHERE.
I HAVE INCREASED POPS MAINLY ALONG THE SC COAST AND OFFSHORE FOR THE
MORNING HOURS TO ACCOUNT FOR THIS ACTIVITY. FORTUNATELY THERE IS NO
SEVERE WEATHER THREAT OWNING TO THE DEEP FRONTAL INVERSION BELOW THE
STORMS AND SMALL CAPE VALUES ALOFT LIMITING POTENTIAL HAIL
PRODUCTION. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
SURFACE LOW PRESSURE MOVED ALMOST DIRECTLY OVER ILM AROUND MIDNIGHT.
NOW THAT THE LOW IS RACING NORTHEAST ACROSS EXTREME EASTERN NC COOL
AIR HAS RUSHED DOWN TO THE CAPE FEAR AND GRAND STRAND BEACHES. LOW
STRATUS CLOUDS WILL BE VERY TOUGH TO ERODE TODAY...AND IN FACT
MODELS SUGGEST A SOLID GRAY OVERCAST WILL PERSIST THROUGH THE
MORNING HOURS...RELUCTANTLY LIFTING INTO A SCT-BKN STRATOCUMULUS
DECK SOMETIME IN THE 11 AM TO 2 PM PERIOD. IT APPEARS THE NAM HAS A
BETTER HANDLE ON THE LATER CLOUD BURNOFF THAN THE GFS...THEREFORE MY
FORECAST HIGHS ARE CLOSE THE NAM AND RANGE FROM THE UPPER 50S NEAR
THE COAST TO AROUND 60 INLAND...10-13 DEGREES BELOW NORMAL.
OF MORE IMMEDIATE CONCERN IS A CLUSTER OF THUNDERSTORMS ACROSS
SOUTHERN GEORGIA ASSOCIATED WITH AN 500 MB VORT MAX ROTATING
NORTHEASTWARD AROUND THE MAIN UPPER LOW STILL BACK ON THE
MISSISSIPPI-ALABAMA BORDER. THIS CONVECTION APPEARS TO BE BASED
AROUND 700 MB AND IS TAKING ADVANTAGE OF STEEPENING LAPSE RATES IN
THE 700-400 MB LAYER AS COLD AIR WITH THE UPPER LOW ADVECTS ACROSS
THE SOUTHEAST. IT IS POSSIBLE THESE SHOWERS AND THUNDERSTORMS WILL
AFFECT COASTAL SOUTH CAROLINA LATER THIS MORNING...WHERE I HAVE A
30-40 PERCENT POP IN THE FORECAST. POPS ELSEWHERE ARE IN THE 10-20
PERCENT RANGE HEDGING FOR ANY EXPANSION IN THIS AREA OF ELEVATED
CONVECTION.
THE AFOREMENTIONED UPPER LOW WILL MOVE EAST ACROSS ALABAMA AND
GEORGIA THIS MORNING...THEN INTO SOUTH CAROLINA BY MID AFTERNOON.
LOW AND MID CLOUDS MAY CONTINUE ALONG THE COAST INTO THE EVENING
HOURS BUT CLEARING SKIES SHOULD DEVELOP FROM WEST TO EAST AS THE
UPPER LOW MOVES ACROSS. A NEW AREA OF SURFACE LOW PRESSURE WILL
DEVELOP WELL OFF THE GA/SC COAST LATE THIS AFTERNOON IN ADVANCE OF
THE UPPER SYSTEM. THIS NEW LOW SHOULD REMAIN TOO FAR AWAY FOR ANY
DIRECT IMPACTS ON OUR AREA...BUT NORTHERLY FLOW BEHIND THIS LOW WILL
HELP MAINLY A CHILLY AIRMASS ACROSS THE CAROLINAS TONIGHT WITH LOWS
FALLING TO 40-45...A FEW DEGREES BELOW NORMAL.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...HIGH PRESSURE WILL BUILD DOWN OVER THE
SOUTHEAST THROUGH THE WEEKEND. A COOLER NORTHERLY FLOW INITIALLY
WILL WEAKEN AND BECOME LIGHT AS IT VEERS AROUND THROUGH SAT NIGHT AS
CENTER OF HIGH SHIFTS CLOSER OVERHEAD AND THEN OFF SHORE BY
MORNING. THE MAX CAA WILL CUT OFF EARLY SATURDAY AS 850 TEMPS DROP
CLOSE TO 3C. EXPECT AFTERNOON HIGHS TO ONCE AGAIN REMAIN BELOW
NORMAL REACHING INTO THE LOW TO MID 60S. CALM WINDS AND CLEAR
SKIES SATURDAY NIGHT WILL PROVIDE MORE IDEAL RADIATIONAL COOLING
CONDITIONS WITH TEMPS DROPPING INTO THE LOWER END OF THE 40S MOST
PLACES...BUT SLIGHTLY WARMER AT THE BEACHES.
BY SUNDAY A RETURN FLOW WILL SET UP WITH LIGHT SOUTHERLY WINDS
BEGINNING A WARMING TREND INTO NEXT WEEK. TEMPS WILL APPROACH
NORMAL VALUES FOR THIS TIME OF YEAR WITH HIGH TEMPS JUST REACHING
INTO THE 70S UNDER PLENTY OF SUNSHINE.
OVERALL A BEAUTIFUL WEEKEND WITH LOTS OF SPRING SUNSHINE BUT
SLIGHTLY COOLER TEMPS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 3 AM FRIDAY...HEADING INTO A MORE SUMMER LIKE PATTERN FOR
THIS TIME OF YEAR. BERMUDA HIGH PRESSURE WITH A WARMER MOISTER
SOUTHERLY RETURN FLOW THROUGH THE PERIOD. A DEEP RIDGE BUILDS
ALOFT WITH HEIGHT RISES PEAKING MID WEEK UP CLOSE TO 585 DM.
AS THE MID TO UPPER RIDGE BUILDS UP THE EAST COAST A DEEPENING
TROUGH WILL DIG DOWN THROUGH THE MID WEST. ALTHOUGH THE RIDGE
HOLDS ON TIGHT THROUGH MUCH OF THE WORK WEEK...THE TROUGH FINALLY
MOVES EAST TOWARD THE AREA PUSHING A COLD FRONT OUR WAY BY THURS
NIGHT INTO FRIDAY. MODELS HAVE PUSHED THE TIMING BACK A BIT AND
THEREFORE LOOKS LIKE NICE WEATHER WILL HOLD OUT THROUGH THURSDAY.
OVERALL A RAIN FREE WEEK WITH A SHARP WARMING TREND BRINGING TEMPS
TO SEVERAL DEGREES ABOVE NORMAL WITH HIGH TEMPS FLIRTING WITH 80
OR SLIGHTLY ABOVE IN PLACES AND MIN TEMPS CLOSE TO WHAT WE HAVE
BEEN EXPERIENCING FOR HIGH TEMPS LATELY. THE COOLER OCEAN TEMPS
WILL MAXIMIZE THE DIFFERENTIAL HEATING ALLOWING FOR A STRONG SEA
BREEZE TO CARRY FAR INLAND MOST AFTERNOONS. THIS WILL BRING COOLER
AIR INLAND BUT WILL ALSO KEEP THE BEACHES MUCH COOLER.
THE SEA BREEZE WILL ALSO PROVIDE A FOCAL POINT FOR ENOUGH
CONVERGENCE TO PRODUCE CU EACH AFTERNOON AND MAY SEE SOME PASSING
HIGH CLOUDS BUT OTHERWISE SHOULD SEE A GOOD DEAL OF SUNSHINE
THROUGH THE WEEK WITH ANY PCP HOLDING OFF UNTIL LATE THURS INTO
FRIDAY.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 18Z...VISIBLE SATELLITE IMAGERY SHOWS THE LOW CLOUD DECK IS
THINNING NEAR KFLO/KLBT AS THE STRATUS IS BEGINNING TO ERODE. ALONG
THE COAST...LOW MVFR CIGS ARE STILL IN PLACE AND WILL LIKELY PERSIST
FOR THE NEXT COUPLE HOURS. ANY LINGERING MVFR CIGS SHOULD LIFT TO
VFR BY LATE AFTERNOON. NORTH WINDS AOB 10 KTS TODAY WILL DIMINISH TO
AROUND 5 KTS TONIGHT. THE SKIES WILL BEGIN CLEARING AFTER 00Z
SATURDAY AS AN UPPER TROUGH CLEARS THE CAROLINA COAST. SFC HIGH
PRESSURE WILL BUILD IN FROM THE NORTH TOMORROW MORNING...BRINGING
SUNNY SKIES AND NORTHEAST WINDS 8-12 KTS ACROSS OUR CWA.
EXTENDED OUTLOOK...VFR CONDITIONS WILL PREVAIL THROUGH WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 12:30 PM FRIDAY...LATEST OBS AND GUIDANCE SUGGEST THAT WE
CAN DROP SMALL CRAFT ADVISORIES EARLY FOR ALL THE REMAINING
COASTAL WATERS. IT IS LIKELY WE ARE NOW ONLY SEEING 6 FOOTERS OVER
THE OUTER EDGES OF THE COASTAL WATERS. PREVIOUS DISCUSSION
FOLLOWS:
TWO CHANGES HAVE BEEN MADE TO THE MARINE FORECAST THIS MORNING.
THE FIRST IS TO INCREASE SHOWER AND T-STORM CHANCES THROUGH THE
MORNING HOURS AS THE WILMINGTON AND CHARLESTON RADARS ARE SHOWING
AN IMPRESSIVE AREA OF SHOWERS AND STORMS MOVING RAPIDLY NORTHEAST
ALONG THE COAST. THE SOUTH CAROLINA COASTAL WATERS WILL BE MOST
STRONGLY AFFECTED BY THIS ACTIVITY...WHICH SHOULD TAPER OFF BY
NOON. ALSO...OBSERVED WIND SPEEDS ARE ABOUT 5 KNOTS STRONGER THAN
EXPECTED ACROSS THE WATERS NORTH OF CAPE FEAR...WHERE RECENTLY
GUSTS AT BOTH WRIGHTSVILLE BEACH AND THE FRYING PAN SHOALS BUOY
OFFSHORE HAVE BEEN AROUND 20 KNOTS. NO OTHER SIGNIFICANT CHANGES
HAVE BEEN MADE. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
SURFACE LOW PRESSURE MOVED OVER WILMINGTON AROUND MIDNIGHT AND IS
NOW RACING NORTHEAST ACROSS THE PAMLICO SOUND. NORTHWESTERLY WINDS
BEHIND THIS LOW HAVE PUSHED THE COLD FRONT A CONSIDERABLE DISTANCE
FROM SHORE...AND COOL NORTHWEST TO NORTH WINDS SHOULD CONTINUE
THROUGH THE DAY. STRONG WINDS YESTERDAY STILL HAVE THE SEA STATE
QUITE AGITATED AND IT WILL TAKE MOST OF THE DAY FOR SEAS TO DECAY
BELOW 6 FEET. FOR THIS REASON THE SMALL CRAFT ADVISORY WILL REMAIN
POSTED INTO THE AFTERNOON HOURS FOR THE SC COASTAL WATERS...AND
UNTIL THIS EVENING FOR THE NC WATERS.
AN APPROACHING UPPER LEVEL LOW WILL INDUCE A NEW LOW TO DEVELOP WELL
OFF THE SC COAST LATE THIS AFTERNOON. WHILE THIS NEW LOW WILL HAVE
NO DIRECT IMPACTS LOCALLY...IT WILL HELP TO ENHANCE THE NORTHERLY
WINDS SOMEWHAT WITH WIND SPEEDS PERHAPS ECLIPSING 15 KNOTS
OVERNIGHT...ESPECIALLY AWAY FROM SHORE.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...HIGH PRESSURE WILL BUILD DOWN INTO THE LOCAL
WATERS THROUGH SATURDAY BEFORE SHIFTING CLOSER OVERHEAD SAT NIGHT
AND THEN OFF SHORE THROUGH SUNDAY. WINDS ON THE FRONT END OF THE
SYSTEM WILL BE NORTHEAST INITIALLY UP TO 15 TO 20 KTS BUT WILL VEER
AROUND THROUGH THE WEEKEND AND LIGHTEN TO 10 KTS OR SO AS GRADIENT
RELAXES. BY SATURDAY EVENING WINDS WILL BE VERY LIGHT OUT OF THE
E-NE AND BY SUNDAY A RETURN FLOW WILL SET UP AS WINDS VEER AROUND
TO THE SOUTH REMAINING 10 KTS OR LESS.
SEAS WILL JUST BE COMING DOWN FROM NEAR SCA CONDITIONS SAT
MORNING IN OUTER WATERS AND WILL CONTINUE TO SUBSIDE THROUGH THE
WEEKEND AS THEY VEER AROUND FROM NORTHEAST TO SOUTHEAST AND
LIGHTEN. BY SUNDAY SEAS WILL BE 3 FT OR LESS.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 3 AM FRIDAY...A MORE SUMMER LIKE PATTERN WILL BE SETTING
UP THROUGH NEXT WEEK AS RETURN FLOW PERSISTS AROUND BERMUDA HIGH
PRESSURE. WINDS WILL REMAIN SOUTHERLY AROUND 10 KTS OR SO. WINDS
AND SEAS WILL SPIKE UP NEAR SHORE IN FAIRLY POTENT SEA BREEZE EACH
AFTERNOON...BUT OTHERWISE EXPECT SEAS 3 FT OR LESS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 3 PM EDT THIS AFTERNOON FOR AMZ256.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR AMZ250-
252.
&&
$$
NEAR TERM...REK/TRA
SHORT TERM...
LONG TERM...
AVIATION...BJR
MARINE...REK/TRA
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1235 PM EDT FRI APR 5 2013
.SYNOPSIS...
LOW PRESSURE SYSTEM JUST OFF THE NORTH CAROLINA COAST WILL
CONTINUE TO LIFT OFF TO THE NORTHEAST AWAY FROM THE AREA THROUGH
TODAY. HIGH PRESSURE WILL BUILD IN BEHIND THIS STORM SYSTEM...
BRINGING A WARMING TREND AND SPRING-LIKE TEMPERATURES THROUGH NEXT
WEEK. A MORE SUMMER-LIKE PATTERN SETS UP THROUGH MID WEEK AS BERMUDA
HIGH PRESSURE DOMINATES BEFORE A COLD FRONT APPROACHES FROM THE WEST
TOWARD LATE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 12:30 PM FRIDAY...OTHER THAN FOR GEORGETOWN COUNTY THE
LATEST GUIDANCE AND RADAR LOOPS SUGGEST THAT PRECIP HAS ENDED FOR
THE DAY. HAVE ALREADY CUT BACK ON POPS WITH THE LATEST
ISSUANCES...AND WILL LIKELY MAY DROP POPS COMPLETELY WITH THE NEXT
FORECAST PACKAGE. PREVIOUS DISCUSSION FOLLOWS:
AN UPPER LEVEL DISTURBANCE MOVING RAPIDLY NORTH THROUGH GEORGIA
AND NOW SOUTH CAROLINA HAS PRODUCED AN IMPRESSIVE AREA OF SHOWERS
AND THUNDERSTORMS EXTENDING FROM GEORGETOWN SC SOUTH BACK INTO
WAYCROSS AND AMERICUS GA VICINITY. THIS CONVECTION IS ELEVATED
WITH THE LIFTING PARCEL LEVEL PROBABLY IN THE VICINITY OF 10000 FT
AGL OR 700 MB. LATEST RUC ANALYSIS SHOWS LAPSE RATES IN THE
700-500 MB LAYER ARE EXCEEDING 7C/KM...AND FORECAST SOUNDINGS FROM
VIRTUALLY ANY MODEL SHOW STEEP LAPSE RATES CONTINUING FOR AT LEAST
ANOTHER 100 MB HIGHER IN THE ATMOSPHERE.
I HAVE INCREASED POPS MAINLY ALONG THE SC COAST AND OFFSHORE FOR THE
MORNING HOURS TO ACCOUNT FOR THIS ACTIVITY. FORTUNATELY THERE IS NO
SEVERE WEATHER THREAT OWNING TO THE DEEP FRONTAL INVERSION BELOW THE
STORMS AND SMALL CAPE VALUES ALOFT LIMITING POTENTIAL HAIL
PRODUCTION. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
SURFACE LOW PRESSURE MOVED ALMOST DIRECTLY OVER ILM AROUND MIDNIGHT.
NOW THAT THE LOW IS RACING NORTHEAST ACROSS EXTREME EASTERN NC COOL
AIR HAS RUSHED DOWN TO THE CAPE FEAR AND GRAND STRAND BEACHES. LOW
STRATUS CLOUDS WILL BE VERY TOUGH TO ERODE TODAY...AND IN FACT
MODELS SUGGEST A SOLID GRAY OVERCAST WILL PERSIST THROUGH THE
MORNING HOURS...RELUCTANTLY LIFTING INTO A SCT-BKN STRATOCUMULUS
DECK SOMETIME IN THE 11 AM TO 2 PM PERIOD. IT APPEARS THE NAM HAS A
BETTER HANDLE ON THE LATER CLOUD BURNOFF THAN THE GFS...THEREFORE MY
FORECAST HIGHS ARE CLOSE THE NAM AND RANGE FROM THE UPPER 50S NEAR
THE COAST TO AROUND 60 INLAND...10-13 DEGREES BELOW NORMAL.
OF MORE IMMEDIATE CONCERN IS A CLUSTER OF THUNDERSTORMS ACROSS
SOUTHERN GEORGIA ASSOCIATED WITH AN 500 MB VORT MAX ROTATING
NORTHEASTWARD AROUND THE MAIN UPPER LOW STILL BACK ON THE
MISSISSIPPI-ALABAMA BORDER. THIS CONVECTION APPEARS TO BE BASED
AROUND 700 MB AND IS TAKING ADVANTAGE OF STEEPENING LAPSE RATES IN
THE 700-400 MB LAYER AS COLD AIR WITH THE UPPER LOW ADVECTS ACROSS
THE SOUTHEAST. IT IS POSSIBLE THESE SHOWERS AND THUNDERSTORMS WILL
AFFECT COASTAL SOUTH CAROLINA LATER THIS MORNING...WHERE I HAVE A
30-40 PERCENT POP IN THE FORECAST. POPS ELSEWHERE ARE IN THE 10-20
PERCENT RANGE HEDGING FOR ANY EXPANSION IN THIS AREA OF ELEVATED
CONVECTION.
THE AFOREMENTIONED UPPER LOW WILL MOVE EAST ACROSS ALABAMA AND
GEORGIA THIS MORNING...THEN INTO SOUTH CAROLINA BY MID AFTERNOON.
LOW AND MID CLOUDS MAY CONTINUE ALONG THE COAST INTO THE EVENING
HOURS BUT CLEARING SKIES SHOULD DEVELOP FROM WEST TO EAST AS THE
UPPER LOW MOVES ACROSS. A NEW AREA OF SURFACE LOW PRESSURE WILL
DEVELOP WELL OFF THE GA/SC COAST LATE THIS AFTERNOON IN ADVANCE OF
THE UPPER SYSTEM. THIS NEW LOW SHOULD REMAIN TOO FAR AWAY FOR ANY
DIRECT IMPACTS ON OUR AREA...BUT NORTHERLY FLOW BEHIND THIS LOW WILL
HELP MAINLY A CHILLY AIRMASS ACROSS THE CAROLINAS TONIGHT WITH LOWS
FALLING TO 40-45...A FEW DEGREES BELOW NORMAL.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...HIGH PRESSURE WILL BUILD DOWN OVER THE
SOUTHEAST THROUGH THE WEEKEND. A COOLER NORTHERLY FLOW INITIALLY
WILL WEAKEN AND BECOME LIGHT AS IT VEERS AROUND THROUGH SAT NIGHT AS
CENTER OF HIGH SHIFTS CLOSER OVERHEAD AND THEN OFF SHORE BY
MORNING. THE MAX CAA WILL CUT OFF EARLY SATURDAY AS 850 TEMPS DROP
CLOSE TO 3C. EXPECT AFTERNOON HIGHS TO ONCE AGAIN REMAIN BELOW
NORMAL REACHING INTO THE LOW TO MID 60S. CALM WINDS AND CLEAR
SKIES SATURDAY NIGHT WILL PROVIDE MORE IDEAL RADIATIONAL COOLING
CONDITIONS WITH TEMPS DROPPING INTO THE LOWER END OF THE 40S MOST
PLACES...BUT SLIGHTLY WARMER AT THE BEACHES.
BY SUNDAY A RETURN FLOW WILL SET UP WITH LIGHT SOUTHERLY WINDS
BEGINNING A WARMING TREND INTO NEXT WEEK. TEMPS WILL APPROACH
NORMAL VALUES FOR THIS TIME OF YEAR WITH HIGH TEMPS JUST REACHING
INTO THE 70S UNDER PLENTY OF SUNSHINE.
OVERALL A BEAUTIFUL WEEKEND WITH LOTS OF SPRING SUNSHINE BUT
SLIGHTLY COOLER TEMPS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 3 AM FRIDAY...HEADING INTO A MORE SUMMER LIKE PATTERN FOR
THIS TIME OF YEAR. BERMUDA HIGH PRESSURE WITH A WARMER MOISTER
SOUTHERLY RETURN FLOW THROUGH THE PERIOD. A DEEP RIDGE BUILDS
ALOFT WITH HEIGHT RISES PEAKING MID WEEK UP CLOSE TO 585 DM.
AS THE MID TO UPPER RIDGE BUILDS UP THE EAST COAST A DEEPENING
TROUGH WILL DIG DOWN THROUGH THE MID WEST. ALTHOUGH THE RIDGE
HOLDS ON TIGHT THROUGH MUCH OF THE WORK WEEK...THE TROUGH FINALLY
MOVES EAST TOWARD THE AREA PUSHING A COLD FRONT OUR WAY BY THURS
NIGHT INTO FRIDAY. MODELS HAVE PUSHED THE TIMING BACK A BIT AND
THEREFORE LOOKS LIKE NICE WEATHER WILL HOLD OUT THROUGH THURSDAY.
OVERALL A RAIN FREE WEEK WITH A SHARP WARMING TREND BRINGING TEMPS
TO SEVERAL DEGREES ABOVE NORMAL WITH HIGH TEMPS FLIRTING WITH 80
OR SLIGHTLY ABOVE IN PLACES AND MIN TEMPS CLOSE TO WHAT WE HAVE
BEEN EXPERIENCING FOR HIGH TEMPS LATELY. THE COOLER OCEAN TEMPS
WILL MAXIMIZE THE DIFFERENTIAL HEATING ALLOWING FOR A STRONG SEA
BREEZE TO CARRY FAR INLAND MOST AFTERNOONS. THIS WILL BRING COOLER
AIR INLAND BUT WILL ALSO KEEP THE BEACHES MUCH COOLER.
THE SEA BREEZE WILL ALSO PROVIDE A FOCAL POINT FOR ENOUGH
CONVERGENCE TO PRODUCE CU EACH AFTERNOON AND MAY SEE SOME PASSING
HIGH CLOUDS BUT OTHERWISE SHOULD SEE A GOOD DEAL OF SUNSHINE
THROUGH THE WEEK WITH ANY PCP HOLDING OFF UNTIL LATE THURS INTO
FRIDAY.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 12Z...RADAR INDICATES SOME SHOWER ACTIVITY NEAR KMYR/KCRE IS
MOVING NORTHEAST UP THE CAROLINA COAST. MOST OF THE ACTIVITY IS
REMAINING OFFSHORE...AND DO NOT EXPECT ANY PCPN FOR KILM ATTM.
WIDESPREAD IFR CIGS ARE BEING REPORTED AT ALL TERMS THIS MORNING.
GFS AND NAM GUIDANCE IN GOOD AGREEMENT THAT IFR WILL PERSIST FOR
MUCH OF THE MORNING...ESPECIALLY ALONG THE COAST. KFLO/KLBT CIGS
WILL LIKELY LIFT ABOVE 1KFT BY MID TO LATE MORNING...WHEREAS
KILM/KMYR/KCRE COULD SEE IFR CONDITIONS LINGER UNTIL MIDDAY. ONCE
THE STRATUS FINALLY LIFTS...EXPECT MVFR IN THE EARLY AFTERNOON TO
BECOME VFR BY LATE AFTERNOON THROUGH THE END OF THE TAF PERIOD.
NORTHWEST WINDS AOB 12 KTS THIS MORNING WILL VEER TO THE NORTH LATER
TODAY...REMAINING AOB 10 KTS. THE SKIES WILL CLEAR OUT OVERNIGHT AS
AN UPPER LOW PUSHES THROUGH THE CAROLINAS.
EXTENDED OUTLOOK...VFR EXPECTED SATURDAY THROUGH TUESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 12:30 PM FRIDAY...LATEST OBS AND GUIDANCE SUGGEST THAT WE
CAN DROP SMALL CRAFT ADVISORIES EARLY FOR ALL THE REMAINING
COASTAL WATERS. IT IS LIKELY WE ARE NOW ONLY SEEING 6 FOOTERS OVER
THE OUTER EDGES OF THE COASTAL WATERS. PREVIOUS DISCUSSION
FOLLOWS:
TWO CHANGES HAVE BEEN MADE TO THE MARINE FORECAST THIS MORNING.
THE FIRST IS TO INCREASE SHOWER AND T-STORM CHANCES THROUGH THE
MORNING HOURS AS THE WILMINGTON AND CHARLESTON RADARS ARE SHOWING
AN IMPRESSIVE AREA OF SHOWERS AND STORMS MOVING RAPIDLY NORTHEAST
ALONG THE COAST. THE SOUTH CAROLINA COASTAL WATERS WILL BE MOST
STRONGLY AFFECTED BY THIS ACTIVITY...WHICH SHOULD TAPER OFF BY
NOON. ALSO...OBSERVED WIND SPEEDS ARE ABOUT 5 KNOTS STRONGER THAN
EXPECTED ACROSS THE WATERS NORTH OF CAPE FEAR...WHERE RECENTLY
GUSTS AT BOTH WRIGHTSVILLE BEACH AND THE FRYING PAN SHOALS BUOY
OFFSHORE HAVE BEEN AROUND 20 KNOTS. NO OTHER SIGNIFICANT CHANGES
HAVE BEEN MADE. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
SURFACE LOW PRESSURE MOVED OVER WILMINGTON AROUND MIDNIGHT AND IS
NOW RACING NORTHEAST ACROSS THE PAMLICO SOUND. NORTHWESTERLY WINDS
BEHIND THIS LOW HAVE PUSHED THE COLD FRONT A CONSIDERABLE DISTANCE
FROM SHORE...AND COOL NORTHWEST TO NORTH WINDS SHOULD CONTINUE
THROUGH THE DAY. STRONG WINDS YESTERDAY STILL HAVE THE SEA STATE
QUITE AGITATED AND IT WILL TAKE MOST OF THE DAY FOR SEAS TO DECAY
BELOW 6 FEET. FOR THIS REASON THE SMALL CRAFT ADVISORY WILL REMAIN
POSTED INTO THE AFTERNOON HOURS FOR THE SC COASTAL WATERS...AND
UNTIL THIS EVENING FOR THE NC WATERS.
AN APPROACHING UPPER LEVEL LOW WILL INDUCE A NEW LOW TO DEVELOP WELL
OFF THE SC COAST LATE THIS AFTERNOON. WHILE THIS NEW LOW WILL HAVE
NO DIRECT IMPACTS LOCALLY...IT WILL HELP TO ENHANCE THE NORTHERLY
WINDS SOMEWHAT WITH WIND SPEEDS PERHAPS ECLIPSING 15 KNOTS
OVERNIGHT...ESPECIALLY AWAY FROM SHORE.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...HIGH PRESSURE WILL BUILD DOWN INTO THE LOCAL
WATERS THROUGH SATURDAY BEFORE SHIFTING CLOSER OVERHEAD SAT NIGHT
AND THEN OFF SHORE THROUGH SUNDAY. WINDS ON THE FRONT END OF THE
SYSTEM WILL BE NORTHEAST INITIALLY UP TO 15 TO 20 KTS BUT WILL VEER
AROUND THROUGH THE WEEKEND AND LIGHTEN TO 10 KTS OR SO AS GRADIENT
RELAXES. BY SATURDAY EVENING WINDS WILL BE VERY LIGHT OUT OF THE
E-NE AND BY SUNDAY A RETURN FLOW WILL SET UP AS WINDS VEER AROUND
TO THE SOUTH REMAINING 10 KTS OR LESS.
SEAS WILL JUST BE COMING DOWN FROM NEAR SCA CONDITIONS SAT
MORNING IN OUTER WATERS AND WILL CONTINUE TO SUBSIDE THROUGH THE
WEEKEND AS THEY VEER AROUND FROM NORTHEAST TO SOUTHEAST AND
LIGHTEN. BY SUNDAY SEAS WILL BE 3 FT OR LESS.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 3 AM FRIDAY...A MORE SUMMER LIKE PATTERN WILL BE SETTING
UP THROUGH NEXT WEEK AS RETURN FLOW PERSISTS AROUND BERMUDA HIGH
PRESSURE. WINDS WILL REMAIN SOUTHERLY AROUND 10 KTS OR SO. WINDS
AND SEAS WILL SPIKE UP NEAR SHORE IN FAIRLY POTENT SEA BREEZE EACH
AFTERNOON...BUT OTHERWISE EXPECT SEAS 3 FT OR LESS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 3 PM EDT THIS AFTERNOON FOR AMZ256.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR AMZ250-
252.
&&
$$
NEAR TERM...TRA
SHORT TERM...REK
LONG TERM...
AVIATION...BJR
MARINE...REK/TRA
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
311 PM CDT FRI APR 5 2013
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 311 PM CDT FRI APR 5 2013
WATER VAPOR IMAGERY THIS AFTERNOON SHOWING A MID-LEVEL SHORTWAVE
TROUGH MOVING THROUGH THE INTERMOUNTAIN WEST. AT THE SURFACE...
CYCLOGENESIS WAS TAKING PLACE EAST OF THE WY ROCKIES WITH A WARM
FRONT EXTENDING THROUGH NEBRASKA. LIFT AHEAD OF THE LOW AND OVER THE
WARM FRONT WAS PRODUCING INCREASING MID-LEVEL CLOUD WITH RADAR
MOSAIC/SURFACE OBSERVATIONS INDICATING SPORADIC -SN REACHING THE
GROUND FROM WEST CENTRAL-SOUTH CENTRAL MN. OTHERWISE...HIGH/MID
CLOUDS WERE INCREASING/THICKENING FROM WEST TO EAST ACROSS THE
FORECAST AREA WITH TEMPERATURES RANGING FROM THE UPPER 30S ACROSS
NORTH CENTRAL WI TO 50 ACROSS PORTIONS OF NORTHEAST IA/FAR SOUTHWEST
WI.
FOR TONIGHT...SURFACE LOW WILL CONTINUE TO DEVELOP AND MOVE OUT OF
THE PLAINS INTO SOUTHERN MN BY 12Z WITH INCREASING 850-700MB
MOISTURE TRANSPORT/ISENTROPIC LIFT AHEAD OF THE LOW FOCUSING INTO
AREAS NORTHEAST OF I-94. AS A RESULT...CONFIDENT ENOUGH TO CARRY
LIKELY TO CATEGORICAL POPS ACROSS THAT AREA...TAPERING OFF TO
CHANCES SOUTHWEST OF I-94. AS FAR AS PRECIPITATION TYPES...RAP
SOUNDINGS NORTHEAST OF I-94 SHOW EVAPORATIVE COOLING AS THE COLUMN
SATURATES...WITH BOUNDARY LAYER STILL WARM ENOUGH TO SUPPORT RAIN.
THE NAM ON THE OTHERHAND COOLS THE ENTIRE COLUMN BELOW 0C FOR ALL
SNOW WHICH SEEMS A BIT AGGRESSIVE. BOTTOM LINE...LOOKS LIKE A
RAIN/SNOW MIX MOVING IN MAINLY ALONG AND NORTH OF I-94 THIS EVENING.
LOOKS LIKE MAIN SNOW AREA WILL BE NORTH OF THE AREA...BUT TAYLOR
COUNTY COULD BE COLD ENOUGH TO SEE ACCUMULATIONS OF 1/2 TO PERHAPS
AS MUCH AS 2 INCHES ACROSS FAR NORTHERN PORTION OF THE COUNTY. AS
WARMER AIR ALOFT MOVES INTO THE AREA AFTER MIDNIGHT...LOOK FOR THE
SNOW TO BECOME MORE OF A RAIN/SLEET MIX...POSSIBLY ALL RAIN TOWARD
MORNING.
MODELS CONTINUE TO SHOW THE LOW MOVING EAST THROUGH CENTRAL WI ON
SATURDAY WITH AREAS ALONG AND SOUTH OF I-90 IN THE WARM SECTOR. RAIN
EXPECTED TO CONTINUE ALONG AND NORTH OF THE LOW. MEANWHILE...THE NAM
DEVELOPS SOME 0-3KM MUCAPE LATE MORNING/AFTERNOON IN THE WARM SECTOR
OF AROUND 400J/KG. THIS WILL BE AHEAD OF FAIRLY STRONG 925-700MB
FRONTOGENESIS ASSOCIATED WITH THE COLD FRONT OF THE LOW. BUFKIT
SHOWING THAT THIS IS LONG/SKINNY CAPE WHICH WILL LIKELY SUSTAIN A
FEW THUNDERSTORMS. BASED ON THIS SIGNAL...WILL CONTINUE THE THREAT
FOR A FEW STORMS IN THE FORECAST MAINLY ALONG/SOUTH OF I-90.
OTHERWISE...LOOK FOR TEMPERATURES TO CLIMB INTO THE 55-60 DEGREE
RANGE SOUTH OF THE WARM FRONT...AND IN THE 40S TO NEAR 50 ALONG AND
NORTH OF I-94. RAIN AND WARMTH FOR SNOWMELT MAY LEAD TO SOME HYDRO
ISSUES. DETAILS OF THIS IS COVERED IN THE HYDROLOGY SECTION BELOW.
THE LOW PULLS EAST INTO THE GREAT LAKES REGION SATURDAY NIGHT WITH
LINGERING RAIN CHANCES CONFINED TO THE EVENING HOURS ALONG AND EAST
OF THE MISSISSIPPI RIVER.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 311 PM CDT FRI APR 5 2013
SUNDAY EXPECTED TO BE DRY AS A RIDGE OF HIGH PRESSURE DRIFTS ACROSS
THE REGION. LOOK FOR IN THE MIDDLE 40S TO MIDDLE 50S.
FOR SUNDAY NIGHT INTO MONDAY...A DEEPENING UPPER LEVEL TROUGH OF LOW
PRESSURE OVER THE WESTERN STATES WILL PRODUCE INCREASING SOUTHWEST
FLOW ALOFT INTO THE UPPER MISSISSIPPI RIVER VALLEY REGION.
CYCLOGENESIS AND BROAD MOISTURE TRANSPORT ACROSS THE PLAINS INTO OUR
AREA WILL PRODUCE A CHANCE OF A RAIN OR RAIN/SNOW MIX SUNDAY NIGHT
AND ALL RAIN ON MONDAY. PLAN ON LOWS SUNDAY NIGHT IN THE 30S TO NEAR
40 WITH HIGHS ON MONDAY IN THE UPPER 40S TO THE MIDDLE 50S.
MEDIUM RANGE MODELS SHOWING A RATHER ACTIVE WEATHER PATTERN FOR THE
REST OF THE WORK WEEK. HOWEVER...THEY OFFER DIFFERING SOLUTIONS WITH
REGARD TO THE EVOLUTION OF THE WESTERN TROUGH AND SURFACE
CYCLOGENESIS AND IMPACT ON THE UPPER MISSISSIPPI RIVER VALLEY
REGION. THE GFS AND GEM SHOWING SOME SIMILARITY IN EJECTING THE
TROUGH/SURFACE LOW TOWARD THE AREA MONDAY NIGHT THROUGH TUESDAY
NIGHT WITH MORE PHASING WITH THE NORTHERN STREAM FLOW. THIS KEEPS US
IN AN OVERALL WARMER/RAIN SCENARIO. THE ECMWF ON THE OTHER HAND
WANTS TO KEEP THE FLOW SPLIT THROUGH TUESDAY WHICH KEEPS THE LOW
OVER THE PLAINS THUS KEEPING AREAS MAINLY NORTH OF I-90 DRY WITH
UPSTREAM RIDGING. THE ECMWF THEN TAKES THE MAIN SURFACE LOW TRACK
FARTHER SOUTH INTO THE OHIO RIVER VALLEY REGION WITH AN INVERTED
TROUGH OVER US. THIS MAY LEAD TO A COLDER RAIN OR RAIN SNOW MIX. WILL
GO WITH A MODEL CONSENSUS FOR NOW AND HOPE FOR BETTER RESOLUTION
WITH LATER RUNS. CONSENSUS YIELDS A CHANCE OF RAIN FROM MONDAY NIGHT
STRAIGHT THROUGH FRIDAY. TEMPERATURES THROUGH THE PERIOD LOOK TO BE
COLDER THAN NORMAL WITH GENERAL TROUGHINESS AND PRECIPITATION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY)
ISSUED 1225 PM CDT FRI APR 5 2013
HIGH PRESSURE WAS RE-TREATING EASTWARD AS AN AREA OF LOW PRESSURE
WAS DEVELOPING OVER THE PLAINS. SWATH OF WARM
ADVECTION/FRONTOGENESIS PUSHING INTO SOUTH CENTRAL MINNESOTA.
05.15Z HRRR TAKES THIS BAND OF FRONTOGENESIS ACROSS THE AREA LATE
THIS AFTERNOON THROUGH EARLY EVENING. QUESTION WILL BE HOW MUCH
LOW LEVEL SATURATION THERE IS FOR LOWER CLOUDS AND SHOWERS. MODELS
SUGGEST VFR CEILINGS AND HAVE TAILORED THE TAFS WITH VFR CEILINGS
WITH SOME SHOWERS. FOCUS THEN LOOKS TO BE NORTH OF THE TAF SITES
THROUGH LATE EVENING AND OVERNIGHT....WITH THE NEXT BATCH OF
PRECIPITATION AFFECTING THE TAF SITES AFTER 12Z SATURDAY AS THE
CEILINGS LOWER INTO THE MVFR CATEGORY.
&&
.HYDROLOGY...
ISSUED AT 311 PM CDT FRI APR 5 2013
RIVER STATUS...
ICE JAM ISSUES NOW BEING REPORTED ON THE BLACK ON THE NORTH SIDE OF
NEILLSVILLE WITH THAWING. HYDROGRAPHS ACROSS THE REST OF AREA SHOW
TRIBUTARY RIVERS AND STREAMS INTO THE MISSISSIPPI RUNNING WITHIN
BANK BUT HIGHER THAN NORMAL GIVEN THE SNOW MELT. MOST OF THE HIGHER
RIVER FLOWS ARE CONFINED TO RIVERS NORTH OF I-90 WHERE SNOW PACK
STILL EXISTS. BESIDES THE BLACK RIVER...THE TREMPEALEAU IS ALSO A
CONCERN AT THE MOMENT.
SNOW PACK...
LATEST NOHRSC DATA SHOWED SNOW WATER EQUIVALENTS STILL IN THE 1-3
INCH RANGE OVER WINONA...BUFFALO...TREMPEALEAU AND JACKSON
COUNTIES...WHILE 2-4 INCH AMOUNTS WERE PRESENT IN CLARK AND TAYLOR
COUNTIES.
RAINFALL...
THE SYSTEM COMING IN FOR TONIGHT AND SATURDAY IS EXPECTED TO PRODUCE
1/4 OF AN INCH OR LESS SOUTHWEST OF I-94 AND AROUND 1/2 INCH
RAINFALL/LIQUID EQUIVALENT FROM ANY SNOW NORTH OF HIGHWAY 10 IN
WISCONSIN. ADDITIONAL RAINFALL IS POSSIBLE SUNDAY NIGHT WITH THE
POTENTIAL FOR MORE MODERATE RAINFALL MONDAY THROUGH WEDNESDAY OF NEXT WEEK.
TEMPERATURES...
TEMPERATURES IN THE MIDDLE 30S TO MIDDLE/UPPER 40S TODAY CONTINUES
TO PRODUCE SNOWMELT. TEMPERATURES MAY NOT FALL BELOW FREEZING
TONIGHT ALONG WITH WARMER CONDITIONS ANTICIPATED ON SATURDAY. THIS
WILL CAUSE ADDITIONAL SNOW MELT. MOST OF THE NEXT 7 DAYS LOOK TO
HAVE DAYTIME TEMPERATURES AT LEAST 40 FOR CONTINUED FAVORABLE SNOW MELT
CONDITIONS.
FROST DEPTH...
FROST DEPTHS ACROSS THE AREA REMAIN DEEP...AVERAGING AROUND 1 FOOT
TO 1 1/2 FEET SOUTH OF I-90...AND UP TO 3 FEET ACROSS PORTIONS OF
NORTH CENTRAL WISCONSIN. THIS WILL LIKELY CAUSE ADDITIONAL RUNOFF OF
SNOW MELT AND FALLEN PRECIPITATION INTO STREAMS AND RIVERS.
SUMMARY...
DUE TO LESS RAINFALL EXPECTED FOR TONIGHT THROUGH SATURDAY...MAIN
FLOODING CONCERN WOULD COME MOSTLY FROM SNOW MELT THE NEXT FEW DAYS.
RIVERS AND STREAMS FROM WINONA AND WABASHA COUNTIES INTO BUFFALO
TREMPEALEAU...JACKSON...CLARK AND TAYLOR CONTINUE BE FOCUS OF
CONCERN. WILL KEEP THE ESF GOING BASED ON THE LISTED FACTORS ABOVE.
POTENTIAL IS THERE FOR A FLOOD WATCH...BUT WILL CONTINUE ESF AND
CONTINUE ASSESSING THE SITUATION AT HAND WITH SNOWMELT AND FALLEN
PRECIPITATION. WILL ALSO CONTINUE TO KEEP A VIGILANT EYE ON ON THE
SITUATION FOR MODERATE RAINFALL POTENTIAL MONDAY THROUGH WEDNESDAY
OF NEXT WEEK.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...RABERDING
HYDROLOGY...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1225 PM CDT FRI APR 5 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 341 AM CDT FRI APR 5 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A SHORTWAVE TROUGH OVER THE PACIFIC NORTHWEST...RIDGING FROM
WEST TEXAS INTO THE NORTHERN PLAINS...AND NORTHERN STREAM TROUGHING
IN THE GREAT LAKES. IN THE WAKE OF THIS TROUGHING...HIGH PRESSURE
HAS BEEN BUILDING IN AT THE SURFACE ACROSS MINNESOTA. 00Z MPX
SOUNDING SHOWED PLENTY OF SUBSIDENCE AND DRY AIR ACCOMPANYING THE
SURFACE HIGH...WITH PRECIPITABLE WATER VALUE AT 0.28 INCHES. AS A
RESULT...SKIES ARE CLEAR ACROSS THE FORECAST AREA. JUST OFF TO THE
WEST...MID AND HIGH LEVEL CLOUDS WERE INCREASING ACROSS THE NORTHERN
PLAINS INTO WESTERN MINNESOTA...WELL DOWNSTREAM OF THE PACIFIC
NORTHWEST SHORTWAVE. THESE CLOUDS ARE ASSOCIATED WITH A WARM
ADVECTION REGIME ON THE TOP OF THE RIDGE...AS WELL AS HELP FROM A
120KT JET STREAK FROM SOUTHERN MANITOBA INTO EASTERN MINNESOTA.
PROFILER AND VAD WIND DATA AT 850MB SHOWED A 30-50 KT SOUTH JET FROM
EASTERN COLORADO INTO THE WESTERN DAKOTAS. ALSO PRESENT AT 850MB WAS
A TIGHT TEMPERATURE GRADIENT...REFLECTED BY 00Z SOUNDINGS OF -6C AT
BISMARCK COMPARED TO +5C AT RAPID CITY AND +10C AT NORTH PLATTE.
DESPITE THE DECENT WARM ADVECTION PATTERN IN PLACE...SURFACE
DEWPOINTS HAVE BEEN SLOW TO RISE. DEWPOINTS WERE ONLY IN THE LOW TO
MID 30S OVER THE CENTRAL PLAINS...WHICH WAS AT LEAST HIGHER THAN IN
THE DAKOTAS WHICH WERE IN THE 20S.
THE FOCUS FOR THE SHORT TERM IS ON TWO PARTS...
1. WARM ADVECTION WELL DOWNSTREAM OF THE PACIFIC NORTHWEST SHORTWAVE
TROUGH
2. EVENTUAL APPROACH OF THE PACIFIC NORTHWEST SHORTWAVE TROUGH
SUBSIDENCE AND DRY AIR ASSOCIATED WITH THE SURFACE HIGH WILL
DOMINATE THIS MORNING. AS WE HEAD INTO THE AFTERNOON...THE UPPER
RIDGE AXIS OVER THE NORTHERN PLAINS IS PROGGED TO SLIDE INTO THE
FORECAST AREA. THUS...AN INCREASE OF THE MID AND HIGH LEVEL CLOUDS
IS LIKELY AS SEEN BACK IN THE DAKOTAS. THE QUESTIONS ARE WILL
PRECIPITATION DEVELOP...AND IF SO WHERE AND WHEN...AS THE WARM
ADVECTION INCREASES THROUGH THE AFTERNOON AND EVENING. THE 05.00Z
GFS/REGIONAL CANADIAN ARE BY FAR THE MOST AGGRESSIVE...DEVELOPING
RAIN ALONG/WEST OF THE MISSISSIPPI RIVER BETWEEN 18-00Z TODAY. THE
05.00Z NAM/05.00Z ECMWF/04.21Z SREF ALSO DEVELOP THE RAIN...BUT KEEP
IT CONFINED NORTHWEST OF THE FORECAST AREA PRIOR TO 00Z. THE LACK OF
MOISTURE CURRENTLY AVAILABLE WOULD SUPPORT THE DRIER SCENARIO...
HOWEVER...850MB MOISTURE TRANSPORT DOES INTENSIFY THROUGH THE DAY
AND BY 00Z IS POINTING ON THE WEST SIDE OF THE FORECAST AREA.
THUS...FELT AT LEAST KEEPING SOME 20-50 PERCENT CHANCES LATE IN THE
DAY ARE APPROPRIATE OVER THE WESTERN PORTIONS OF THE FORECAST
AREA...HIGHEST FROM WABASHA INTO DODGE COUNTIES.
FOR TONIGHT...MODELS PROG THE PACIFIC NORTHWEST SHORTWAVE TROUGH TO
ENTER WESTERN SOUTH DAKOTA...CAUSING A SURFACE LOW TO FORM AND
DEEPEN OVER SOUTHERN SOUTH DAKOTA. PERSISTENT AND INTENSIFYING WARM
ADVECTION AHEAD OF THIS SHORTWAVE TROUGH AND SURFACE LOW LOOKS TO
EXPAND THE AREA OF PRECIPITATION OVER MOST LOCATIONS EAST OF THE
MISSISSIPPI RIVER IN THE EVENING...WHICH THEN LIFTS NORTHEAST AFTER
MIDNIGHT. EVAPORATIVE COOLING MAY CAUSE THE PRECIPITATION TO SWITCH
FROM RAIN TO SNOW IN THE EVENING NORTHEAST OF I-94...BUT EVENTUALLY
WARMER AIR ADVECTS IN THERE AFTER MIDNIGHT ALOFT AND THEN SURFACE
TO CAUSE A CHANGE-OVER TO SLEET AND RAIN. IF TEMPERATURES CAN HOLD
BELOW FREEZING...A VERY BRIEF PERIOD OF FREEZING RAIN WOULD OCCUR.
MODEL CONSENSUS CONTINUES TO FAVOR ALONG/NORTHEAST OF I-94 TO HAVE
THE BULK OF THE PRECIPITATION...THUS PRECIPITATION CHANCES NEAR 100
SEEMS REASONABLE. REGARDING SNOWFALL ACCUMULATION...GIVEN THE
GENERAL WARM SENSE TO THIS WARM ADVECTION EVENT...NOTED BY 850MB
TEMPS THAT ARE ONLY -2 TO -4C WHEN IT IS SNOWING...SNOW TO WATER
RATIOS SHOULD ONLY MAX OUT AROUND 10 TO 1. WITH UPWARDS OF 0.1-0.3
INCHES OF QPF PROGGED...SNOW TOTALS COULD BE AS MUCH AS 3
INCHES...THOUGH THE MAJORITY SHOULD END UP IN THE 1 TO 2 INCH
RANGE...NOT ENOUGH FOR AN ADVISORY AT THIS POINT. COULD USE THE MIX
PRECIPITATION AS A NEED FOR THE ADVISORY...BUT CONFIDENCE ON THE
AMOUNT OF MIXED PRECIPITATION IS TOO LOW TO WARRANT ONE.
TEMPERATURES TODAY WILL END UP COOLER COMPARED TO YESTERDAY DUE TO
INCREASING CLOUDS AS WELL AS 850MB TEMPS BETWEEN -2 AND -6C AT 18Z.
FOR TONIGHT...INCREASING SOUTHERLY WINDS PLUS CLOUDS SHOULD HELP
KEEP TEMPERATURES UP AT OR ABOVE FREEZING. IN FACT...EXPECTING
TEMPERATURES TO CLIMB LATE IN THE NIGHT AS THE SURFACE WARM FRONT
LIFTS NORTH TOWARDS I-94.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 341 AM CDT FRI APR 5 2013
HIGHLIGHTS:
1. CURRENT PACIFIC NORTHWEST SHORTWAVE TROUGH PROGGED TO MOVE
THROUGH THE AREA ON SATURDAY
2. POTENTIAL FOR AN ACTIVE BUT HARD TO TIME PRECIPITATION PATTERN
SUNDAY NIGHT AND BEYOND.
MODELS ARE IN REALLY GOOD AGREEMENT TRACKING THE SHORTWAVE TROUGH
THAT WAS OVER SOUTH DAKOTA LATE TONIGHT INTO AND POSSIBLY THROUGH
THE FORECAST AREA ON SATURDAY. STRONG DYNAMIC FORCING WITH THIS
SHORTWAVE...NOTED SIMPLY BY 60-90 METER HEIGHT FALLS IN 12 HOURS AT
500MB...ALONG WITH THAT SURGE OF 850MB MOISTURE TRANSPORT AHEAD OF
THE SHORTWAVE PROVIDING MOISTURE SHOULD HELP PRODUCE RAIN ACROSS
MOST OF THE FORECAST AREA. THE ONLY MODEL NOT SHOWING THIS IS THE
05.00Z NAM...AT LEAST SOUTH OF I-90...WHICH SEEMS ODD GIVEN THE
FORCING. THE 05.00Z REGIONAL CANADIAN IS ACTUALLY QUITE ROBUST SOUTH
OF I-90 WITH QPF AMOUNTS OF 0.1-0.25 INCHES WITH A FEW ISOLATED 0.5
INCH AMOUNTS FROM VERNON INTO ADAMS COUNTIES. IT APPEARS THE HEAVIER
QPF IS A RESULT OF CONVECTIVE ELEMENTS FORMING AHEAD OF THE
SHORTWAVES ASSOCIATED COLD FRONT AT THE SURFACE. INSTABILITY IS
FAIRLY MEAGER DUE TO CAPPING AROUND 750MB AND LIMITED MOISTURE.
HOWEVER...THERE IS A ZONE OF NEGATIVE EPV DUE TO UPRIGHT INSTABILITY
IN CROSS-SECTIONS AROUND 700MB...THUS A FEW THUNDERSTORMS CANNOT BE
RULED OUT. PRECIPITATION SHOULD SHIFT OFF TO THE EAST PRETTY QUICK
LATE IN THE AFTERNOON INTO THE EARLY EVENING FOR MOST OF THE
AREA...AS STRONG SUBSIDENCE COMES IN BEHIND THE SHORTWAVE TROUGH.
ONLY PLACE THIS MAY NOT OCCUR AS FAST IS NORTH AND EAST OF
I-94...DUE TO THE SUGGESTION OF A SHORTWAVE COMING IN BEHIND THE
SHORTWAVE TROUGH AND A MID-LEVEL FRONTOGENESIS ZONE DROPPING
SOUTHEAST. TEMPERATURES MAY COOL ENOUGH TO ALLOW FOR SOME SNOW OUT
OF THIS PRECIPITATION BEFORE IT ENDS BY MIDNIGHT. VERY LITTLE
ACCUMULATION ANTICIPATED...THOUGH.
A MAJOR PATTERN CHANGE IS FORECAST TO TAKE PLACE SUNDAY AS A POTENT
SHORTWAVE TROUGH IMPACTS AND DIGS INTO THE PACIFIC NORTHWEST.
HEADING INTO THE EARLY PORTION OF THE WORK WEEK...MODELS ARE IN GOOD
AGREEMENT DIGGING THIS TROUGH SOUTH INTO THE FOUR CORNERS REGION...
SETTING UP A SOUTHWEST FLOW PATTERN INTO THE FORECAST AREA. THIS
MEANS HARD TO TIME SHORTWAVES AND THUS PLENTY OF UNCERTAINTY. TAKE
FOR EXAMPLE SUNDAY NIGHT WHERE THE 05.00Z ECMWF/NAM BRING A
SHORTWAVE THROUGH THE AREA WITH WIDESPREAD QPF. THE 05.00Z CANADIAN
IS EVEN MORE POTENT WITH THIS SHORTWAVE AND A BIT FARTHER SOUTHEAST.
ON THE OTHER HAND...THE 05.00Z GFS DOES NOT SHOW THE SHORTWAVE AT
ALL...THUS RESULTING IN A DRY FORECAST. MAJORITY HERE SUGGESTS AT
LEAST 30-50 PERCENT PRECIPITATION CHANCES ARE NEEDED. MOST OF THE
PRECIPITATION SHOULD FALL AS RAIN...BUT COULD MIX WITH SNOW
ALONG/NORTHEAST OF I-94.
THE MOST INTERESTING TIME PERIOD OF NEXT WEEK IS TUESDAY INTO
WEDNESDAY...AS THE UPPER TROUGH IN THE SOUTHWEST U.S. EJECTS OUT.
THERE REMAINS A WHOLE LOT OF UNCERTAINTY ON THE TIMING AND DETAILS
OF THIS EJECTION. HOWEVER...EVERY MODEL AVAILABLE AT THIS POINT HAS
SOME SYSTEM AFFECTING THE AREA. WE COULD END UP SEEING CONVECTION IN
THE GFS SCENARIO...POTENTIAL FOR MODERATE TO HEAVY RAINFALL IN ANY
MODEL...AND EVEN SOME SNOW ON THE BACK SIDE OF THE SYSTEM ONCE THE
UPPER TROUGH MOVES OVERHEAD. WE WILL HAVE TO KEEP A WATCH ON THIS
PERIOD. GIVEN THE CONSENSUS AGREEMENT FOR PRECIPITATION TUESDAY INTO
TUESDAY NIGHT...RAISED PRECIPITATION CHANCES DURING THIS PERIOD. MAY
NEED TO RAISE CHANCES FOR WEDNESDAY AS WELL.
&&
.AVIATION...THROUGH 18Z SATURDAY
1225 PM CDT FRI APR 5 2013
HIGH PRESSURE WAS RE-TREATING EASTWARD AS AN AREA OF LOW PRESSURE
WAS DEVELOPING OVER THE PLAINS. SWATH OF WARM
ADVECTION/FRONTOGENESIS PUSHING INTO SOUTH CENTRAL MINNESOTA.
05.15Z HRRR TAKES THIS BAND OF FRONTOGENESIS ACROSS THE AREA LATE
THIS AFTERNOON THROUGH EARLY EVENING. QUESTION WILL BE HOW MUCH
LOW LEVEL SATURATION THERE IS FOR LOWER CLOUDS AND SHOWERS. MODELS
SUGGEST VFR CEILINGS AND HAVE TAILORED THE TAFS WITH VFR CEILINGS
WITH SOME SHOWERS. FOCUS THEN LOOKS TO BE NORTH OF THE TAF SITES
THROUGH LATE EVENING AND OVERNIGHT....WITH THE NEXT BATCH OF
PRECIPITATION AFFECTING THE TAF SITES AFTER 12Z SATURDAY AS THE
CEILINGS LOWER INTO THE MVFR CATEGORY.
&&
.HYDROLOGY...
ISSUED AT 341 AM CDT FRI APR 5 2013
RIVER STATUS...
HYDROGRAPHS ACROSS THE AREA SHOW TRIBUTARY RIVERS AND STREAMS INTO
THE MISSISSIPPI RUNNING WITHIN BANK FLOWS WITH A FEW HIGHER THAN
NORMAL GIVEN THE SNOW MELT. MOST OF THE HIGH RIVER FLOWS ARE
CONFINED TO RIVERS NORTH OF I-90 WHERE SNOW PACK STILL EXISTS. THE
WHITEWATER...TREMPEALEAU AND BLACK RIVERS ARE OF CONCERN AT THE
MOMENT.
SNOW PACK...
LATEST NOHRSC DATA SHOWED SNOW WATER EQUIVALENTS STILL IN THE 1-2
INCH RANGE OVER WINONA...BUFFALO...TREMPEALEAU AND JACKSON
COUNTIES...WHILE 2-3 INCH AMOUNTS WERE PRESENT IN CLARK AND TAYLOR
COUNTIES.
RAINFALL...
THE SYSTEM COMING IN FOR TONIGHT AND SATURDAY NOW LOOKS TO NOT
PRODUCE AS MUCH RAINFALL AS PREVIOUSLY EXPECTED...MOSTLY LESS THAN
1/3 OF AN INCH SOUTHWEST OF I-94 TO 1/3 TO 1/2 INCH NORTH OF I-94.
NOTE THAT SOME SNOW IS FORECAST TONIGHT NORTH AND EAST OF
I-94...WHICH COULD TOTAL UP TO 0.3 OF LIQUID EQUIVALENT. ADDITIONAL
RAINFALL IS POSSIBLE SUNDAY NIGHT WITH POTENTIAL FOR MODERATE TO
HEAVY RAINFALL TUESDAY INTO WEDNESDAY OF NEXT WEEK.
TEMPERATURES...
A COOLER DAY BUT STILL PLENTY WARM ENOUGH FOR SNOW MELT IS EXPECTED
TODAY AS HIGHS CLIMB INTO THE 40S. PROBLEM TONIGHT IS THAT
TEMPERATURES MAY NOT FALL BELOW FREEZING AND WITH WARMER CONDITIONS
ANTICIPATED ON SATURDAY...WE COULD REALLY SEE SOME SNOW MELT. MOST
OF THE NEXT 7 DAYS LOOK TO HAVE DAYTIME TEMPERATURES AT LEAST
40...THUS FAVORABLE CONDITIONS ARE IN PLACE FOR SNOW MELT EVERY DAY.
FROST DEPTH...
FROST REMAINS FAIRLY DEEP IN THE GROUND STILL. AS OF 7 AM APRIL
4TH...CUBA CITY WI WAS AT 16 INCHES...WHITEHALL WAS AT 19
INCHES...AND BLOOMER IN CHIPPEWA COUNTY WAS AT 38 INCHES.
SUMMARY...
NOW THAT LESS RAINFALL IS FORECAST THAN EXPECTED FOR TONIGHT AND
SATURDAY...ANY FLOODING CONCERN WOULD COME MOSTLY FROM SNOW MELT THE
NEXT FEW DAYS. CERTAINLY ANY RIVERS AND STREAMS FROM WINONA AND
WABASHA COUNTIES INTO BUFFALO TREMPEALEAU...JACKSON...CLARK AND
TAYLOR WOULD BE OF CONCERN. HAVE DECIDED TO KEEP THE ESF GOING
AND EXPANDED IT INTO WINONA COUNTY GIVEN THE ISSUES BEING
EXPERIENCED ON THE WHITEWATER RIVER. CONSIDERED ISSUING A FLOOD
WATCH FOR JUST RIVERS...BUT GIVEN THAT LESS RAINFALL IS EXPECTED
AND WE ALREADY HAVE EXPERIENCED RIVERS IN AND OUT OF MINOR FLOOD
STAGE THE LAST FEW DAYS...FEEL THE ESF IS STILL VALID. MAY STILL
NEED A FLOOD WATCH...THOUGH...AS CERTAINTY INCREASES ABOUT THE
AMOUNT OF SNOW MELT THIS WEEKEND. EITHER WAY...DEFINITELY NEED TO
KEEP AN EYE ON TUESDAY INTO WEDNESDAY OF NEXT WEEK.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RABERDING
HYDROLOGY...AJ