RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Sun Feb 1 08:32:02 UTC 2015.
MD 0048 CONCERNING HEAVY SNOW FOR CNTRL AND SE IA...NE MO...NRN IL
MESOSCALE DISCUSSION 0048
NWS STORM PREDICTION CENTER NORMAN OK
1013 PM CST SAT JAN 31 2015
AREAS AFFECTED...CNTRL AND SE IA...NE MO...NRN IL
CONCERNING...HEAVY SNOW
VALID 010413Z - 011015Z
SUMMARY...AREAS OF HEAVY SNOW ARE EXPECTED TO DEVELOP LATE THIS
EVENING THROUGH THE OVERNIGHT PERIOD ACROSS CNTRL IA...SE IA...NE MO
EWD INTO NRN IL. SNOWFALL RATES COULD REACH 1 INCH PER HOUR IN SOME
LOCATIONS WITHIN THE MCD AREA. DUE TO SFC TEMPS BEING NEAR
FREEZING...IMPACTS OF ANY HEAVY SNOWFALL SHOULD REMAIN LESSENED.
DISCUSSION...THE LATEST SFC ANALYSIS SHOWS A 1009 MB LOW OVER WCNTRL
KS WITH A QUASI-STATIONARY FRONTAL BOUNDARY EXTENDING FROM THE SFC
LOW ENEWD TO THE VICINITY OF OMAHA NEB AND DES MOINES IA. POCKETS OF
MODERATE SNOWFALL ARE ALREADY ONGOING ALONG AND SOUTH OF THE
BOUNDARY FROM SE NEB INTO SCNTRL IA AND FAR NRN MO. THIS IS IN
RESPONSE TO ISENTROPIC LIFT ASSOCIATED WITH LEFT EXIT REGION OF A 40
TO 50 KT LOW TO MID-LEVEL JET. THE HRRR SUGGESTS THIS FEATURE WILL
MOVE SLOWLY EWD ACROSS SE IA INTO NRN IL DURING THE OVERNIGHT PERIOD
HELPING TO ENHANCE SNOWFALL RATES. AS A RESULT...BANDS OF SNOW ARE
EXPECTED TO CONTINUE DEVELOPING IN CNTRL AND SRN IA...SPREADING
SLOWLY EWD INTO NRN IL OVER THE NEXT 2 TO 4 HOURS. ALTHOUGH SFC
TEMPS REMAIN JUST ABOVE FREEZING IN MANY LOCATIONS WITHIN THE MCD
AREA...TEMPS SHOULD FALL TO NEAR OR SLIGHTLY BELOW FREEZING AS
WET-BULBING AND DIURNAL COOLING OCCURS. SNOWFALL RATES COULD REACH
NEAR 1 INCH PER HOUR WITHIN THE HEAVIEST PARTS OF THE BANDS. THE
POTENTIAL IS EXPECTED TO INCREASE FROM WEST TO EAST WITH NRN IL
BEING IMPACTED AFTER MIDNIGHT. DUE TO THE RELATIVELY WARM SFC TEMPS
NEAR FREEZING...THE IMPACT OF ANY HEAVY SNOW SHOULD REMAIN LESSENED.
..BROYLES.. 02/01/2015
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...LOT...ILX...LSX...DVN...DMX...EAX...
LAT...LON 41008848 40578966 40139233 40349355 40879390 41629395
42319323 42149116 41848878 41008848
Read more
SPC 1200Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1158 PM CST SAT JAN 31 2015
VALID 011200Z - 021200Z
...THERE IS A MRGL RISK OF SVR TSTMS FROM PARTS OF SERN TX EWD TO
PARTS OF WRN AL...
...SUMMARY...
NUMEROUS SHOWERS AND A SCATTERED THUNDERSTORMS WILL OCCUR FROM PARTS
OF TEXAS THROUGH PORTIONS OF THE LOWER MISSISSIPPI VALLEY AND GULF
COAST STATES ON SUNDAY.
...SYNOPSIS...
HIGHLY AMPLIFIED FLOW FIELD ALOFT IS PROGGED ACROSS THE U.S.
SUNDAY...AS A TROUGH INITIALLY OVER THE CENTRAL U.S. STRENGTHENS AS
IT DIGS ESEWD ACROSS THE MID MS AND INTO THE OH/TN VALLEYS WITH
TIME. AS THIS TROUGH ADVANCES...A DEEPENING SURFACE LOW INITIALLY
OVER THE LOWER MO VALLEY IS FORECAST TO SHIFT EWD ACROSS THE OH
VALLEY/MIDWEST WITH TIME...REACHING THE MID ATLANTIC REGION LATE IN
THE PERIOD. A TRAILING COLD FRONT -- PROGGED TO BE SWEEPING ACROSS
THE TN/LOWER MS/SABINE RIVER VALLEYS DURING THE AFTERNOON AND
EVENING WILL FOCUS AN EWD-MOVING BAND OF SHOWERS AND SCATTERED
THUNDERSTORMS.
...PARTS OF E TX EWD ACROSS THE LOWER MS VALLEY TO WRN AL...
A PARTIALLY MODIFIED GULF BOUNDARY LAYER /DEWPOINTS MAINLY IN THE
50S INLAND AND LOWER 60S NEAR THE GULF COAST/ WILL CONTINUE
STREAMING NWD AHEAD OF A SURFACE COLD FRONT ADVANCING SEWD ACROSS
THE WRN AND CENTRAL GULF COAST STATES. DIURNAL HEATING BOOSTING
SURFACE-BASED CAPE TO A FEW HUNDRED J/KG AND LINEAR FORCING ALONG
THE ADVANCING BOUNDARY SHOULD RESULT IN DEVELOPMENT OF A
BROKEN/LOW-TOPPED LINE OF SHOWERS AND SCATTERED THUNDERSTORMS -- THE
STRONGEST OF WHICH EXPECTED TO OCCUR WITHIN A ZONE FROM PARTS OF
SERN TX EWD ACROSS CENTRAL AND SRN MS/WRN AL. THOUGH MODEST AMOUNT
OF INSTABILITY EXPECTED SHOULD LIMIT CONVECTIVE INTENSITY...ROUGHLY
UNIDIRECTIONAL WSWLY FLOW INCREASING WITH HEIGHT TO ROUGHLY 50 KTS
AT MID LEVELS MAY BE SUFFICIENT TO ALLOW A FEW STRONGER/EMBEDDED
CELLS TO EVOLVE WITHIN THE LINE. GIVEN RELATIVELY FAST STORM
MOTION...A FEW STRONGER/DAMAGING GUSTS APPEAR POSSIBLE -- THUS
WARRANTING INCLUSION OF 5% WIND PROBABILITY/MARGINAL CATEGORICAL
RISK AREA THIS FORECAST -- MAINLY FOR THE AFTERNOON AND EARLY
EVENING TIME FRAME BEFORE STORMS DIURNALLY WEAKEN AFTER DARK.
..GOSS.. 02/01/2015
Read more
SPC 0700Z Day 2 Outlook
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1149 PM CST SAT JAN 31 2015
VALID 021200Z - 031200Z
...NO SVR TSTM AREAS FORECAST...
...SUMMARY...
A FEW THUNDERSTORMS WILL BE POSSIBLE MAINLY OVER THE NORTHERN HALF
OF FLORIDA MONDAY MORNING INTO EARLY AFTERNOON...BUT COVERAGE SHOULD
REMAIN SPARSE. OTHER STORMS MAY OCCUR MONDAY MORNING OVER THE NORTH
CAROLINA OUTER BANKS.
...SYNOPSIS...
SHORTWAVE TROUGH AND ITS ACCOMPANYING COLD FRONT WILL EXIT THE
ATLANTIC SEABOARD MONDAY AFTERNOON WITH TRAILING PORTIONS OF THE
FRONT CONTINUING SWD THROUGH THE FL PENINSULA DURING THE DAY.
...FL...
LOW-MID 60S F LOW-LEVEL DEWPOINTS WILL ADVECT THROUGH THE FL
PENINSULA MONDAY...BUT INSTABILITY WILL REMAIN VERY WEAK /MUCAPE AOB
300 J/KG/ OWING TO POOR LAPSE RATES AND AREAS OF CLOUDS. SHOWERS AND
POSSIBLY A FEW THUNDERSTORMS SHOULD CONTINUE ALONG THE FRONT INTO
NRN AND CNTRL FL. DEEPER AND STRONGER FORCING ASSOCIATED WITH THE
SHORTWAVE TROUGH WILL REMAIN NORTH OF THE PENINSULA. THIS ALONG WITH
THE EXPECTED VERY MARGINAL THERMODYNAMIC ENVIRONMENT SUGGEST
THUNDERSTORM COVERAGE SHOULD REMAIN SPARSE.
..DIAL.. 02/01/2015
Read more
SPC 0830Z Day 3 Outlook
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0230 AM CST SUN FEB 01 2015
VALID 031200Z - 041200Z
...NO SVR TSTM AREAS FORECAST...
...SUMMARY...
A FEW THUNDERSTORMS MIGHT OCCUR OVER DEEP SOUTH TEXAS TUESDAY.
...SYNOPSIS...
UPPER PATTERN WILL BE CHARACTERIZED BY A BROAD...LOW-AMPLITUDE
NRN-STREAM TROUGH OVER THE ERN HALF OF THE COUNTRY TUESDAY AND AN
UPSTREAM RIDGE OVER THE PACIFIC NW. MODEL CONSENSUS IS THAT THE
CUTOFF UPPER LOW CURRENTLY OVER THE BAJA AREA WILL MOVE THROUGH NRN
MEXICO AND REACH SRN TEXAS SOMETIME LATER TUESDAY NIGHT.
...SRN TX...
A LARGE AREA OF CP SFC HIGH PRESSURE WILL EXTEND FROM THE ERN U.S.
SWWD INTO ERN AND SRN TX. A WEAK SLY LLJ IS FORECAST OVER SRN TEXAS
DOWNSTREAM FROM APPROACHING UPPER TROUGH...AND THIS WILL CONTRIBUTE
TO ISENTROPIC ASCENT AND THETA-E ADVECTION ABOVE THE SFC RIDGE AXIS.
WIDESPREAD SHOWERS ARE EXPECTED TO DEVELOP IN RESPONSE TO THIS
PROCESS FROM SRN THROUGH SERN TX. MID-LEVEL LAPSE RATES MAY UNDERGO
AT LEAST MODEST STEEPENING WITH APPROACH OF THE UPPER TROUGH...AND
THIS MIGHT EVENTUALLY SUPPORT AN ELEVATED CONVECTIVE LAYER DEEP
ENOUGH FOR A FEW THUNDERSTORMS.
..DIAL.. 02/01/2015
Read more
|
RSS Feed