Acompanhamento e Previsão 2014

Vitor V escreveu:Pelos noticiários, esse é a pior  sequencia da história de chuvas/Ciclones na Inglaterra.

Então minha impressão  que  estava fora do normal algo por lá estava correta.

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0613 AM CST THU FEB 20 2014

VALID 201300Z - 211200Z

...THERE IS A MDT RISK OF SVR TSTMS LATE THIS AFTERNOON INTO TONIGHT
FOR A SMALL PART OF SRN IND...WRN AND CNTRL KY...WRN AND MIDDLE
TN...NRN MS AND FAR NWRN AL...

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE OH VALLEY TO CNTRL
GULF COAST...

--POTENTIALLY WIDESPREAD DAMAGING WIND EVENT OVER PARTS OF THE OH
AND TN VALLEYS INTO THE LOWER MS VALLEY AND CNTRL GULF STATES LATE
THIS AFTERNOON THROUGH TONIGHT--

...SYNOPSIS...

AN INITIALLY NEUTRAL-TILTED SHORT-WAVE TROUGH OVER THE HIGH PLAINS
AS OF 12Z WILL ASSUME AN INCREASING NEGATIVE TILT AS A 100+ KT MID
LEVEL JET STREAK OVER THE SRN PLAINS ROUNDS THE TROUGH BASE AND
SUBSEQUENTLY DEVELOPS NEWD INTO THE GREAT LAKES AND OH VALLEY BY
21/12Z. THIS PROCESS WILL PROMOTE SUBSTANTIAL INTENSIFICATION OF THE
OVERALL SYNOPTIC SYSTEM...LEADING TO A CLOSED MID LEVEL CIRCULATION
OVER THE UPPER MIDWEST AND A CORRIDOR OF 12-HR HEIGHT FALLS
EXCEEDING 100-200 M AT 500 MB ALONG THE SYSTEM TRACK.

AT THE SURFACE...LOW PRESSURE OVER CNTRL KS WILL UNDERGO SIGNIFICANT
DEEPENING LATER TODAY THROUGH TONIGHT WHILE DEVELOPING NEWD TO THE
VICINITY OF THE WI-IL BORDER BY 21/00Z AND THEN LAKE SUPERIOR BY
21/12Z WHERE IT WILL HAVE BECOME DEEPLY OCCLUDED. MEANWHILE...THE
TRAILING COLD FRONT IS EXPECTED TO STRENGTHEN MARKEDLY LATER TODAY
FROM THE MID MS VALLEY TO ARKLATEX BEFORE SWEEPING EWD THROUGH THE
OH AND TN VALLEYS...AS WELL AS THE WRN/CNTRL GULF COAST STATES. THE
MIGRATORY LOW AND COLD FRONT WILL BE PRECEDED BY A W-E-ORIENTED WARM
FRONT WHICH WILL DEVELOP NWD THROUGH THE OH VALLEY. THE POLEWARD
ADVANCEMENT OF THIS BOUNDARY WILL LIKELY BE SLOWED OWING TO THE
INFLUENCE OF SIGNIFICANT SNOW COVER TO THE NORTH OF THE I-70
CORRIDOR.

...MID/LOWER MS VALLEY EWD THROUGH THE OH/TN VALLEYS AND CNTRL GULF
STATES THIS AFTERNOON THROUGH TONIGHT...

THE CYCLOGENETIC CHARACTER OF THE SYNOPTIC SYSTEM WILL PROMOTE A
MARKED INCREASE IN THE BREADTH AND INTENSITY OF WIND MAXIMA...BOTH
IN THE LOW LEVELS AND ALOFT. THIS IN TURN WILL HASTEN THE POLEWARD
TRANSPORT OF A PARTIALLY MODIFIED AIR MASS BENEATH A RESIDUAL STEEP
MIDLEVEL LAPSE RATE PLUME...AS WELL AS ENHANCE DEEP-LAYER SHEAR
ACROSS THE EXPANDING WARM SECTOR.

LATEST MODEL GUIDANCE REMAINS CONSISTENT WITH EARLIER DATA IN
SUGGESTING THE GRADUAL DEEPENING OF A PRE-FRONTAL CONFLUENCE BAND OF
CONVECTION INTO TSTMS BY MID TO LATE AFTERNOON FROM NEAR THE
OH-MS-RIVER CONFLUENCE SWWD TO AT LEAST N-CNTRL LA. AT THE SAME
TIME...LOW-TOPPED TSTMS ARE EXPECTED TO EVOLVE UPSTREAM ALONG THE
COLD FRONT FROM E-CNTRL MO/W-CNTRL IL TO NWRN LA...AS THE
FRONTOGENETICALLY FORCED CIRCULATION IN THE LOW-LEVELS IS COUPLED
WITH THE MID TO UPPER-LEVEL HEIGHT FALLS/DCVA PRECEDING THE MIDLEVEL
TROUGH.

CONSENSUS OF CONVECTION-ALLOWING MODEL DATA INDICATE A RAPID
TRANSITION TO A FAST-MOVING SQUALL LINE/QLCS AS THE TWO INCIPIENT
CONVECTIVE BANDS MERGE. GIVEN A MOIST AND AT LEAST MODESTLY UNSTABLE
AIR MASS /I.E. MLCAPE OF 500-750 J PER KG/ AND STRONG ENVIRONMENTAL
SHEAR /I.E. EFFECTIVE BULK SHEAR OF 50-70 KT AND EFFECTIVE SRH OF
200-400 M2 PER S2/...THE POTENTIAL WILL EXIST FOR EMBEDDED
BOWING/LEWP STRUCTURES CAPABLE OF WIDESPREAD DAMAGING WINDS AND A
FEW MESOVORTEX-RELATED TORNADOES. THIS IS ESPECIALLY THE CASE FROM
WRN/CNTRL KY INTO NRN MS/NWRN AL WHERE THE MOST FAVORABLE OVERLAP OF
FORCING FOR ASCENT...INSTABILITY AND VERTICAL SHEAR WILL EXIST.

EXPECT THE SQUALL LINE /AND ASSOCIATED SEVERE RISK/ TO RAPIDLY
ADVANCE THROUGH THE OH/TN VALLEYS TONIGHT WITH THE CONVECTIVE BAND
GRADUALLY WEAKENING AS IT REACHES THE CNTRL APPALACHIANS BY 21/12Z.
FARTHER SOUTH ACROSS MS/AL/SERN LA...THE STORMS WILL PROGRESS MORE
SLOWLY WITH THE LINE POSSIBLY BREAKING INTO SEGMENTS OR MORE
DISCRETE CELLS. GIVEN THE GRADUAL INFLUX OF A MORE MOIST BOUNDARY
LAYER INTO THIS REGION...AN INCREASE IN SUPERCELLULAR TORNADO
POTENTIAL IS POSSIBLE AFTER 03Z OVER ERN MS INTO WRN AL. AS
SUCH...FIVE PERCENT TORNADO PROBABILITIES HAVE BEEN ADJUSTED EWD TO
ACCOMMODATE THIS RISK.

...LOWER MO/MID MS VALLEYS TODAY...

A CLUSTER OF STRONG TO SEVERE ELEVATED TSTMS IS IN PROGRESS AS OF
12Z OVER NWRN MO...TO THE NORTH OF THE SURFACE WARM FRONT WHERE
LOW-LEVEL WAA AND MOISTURE TRANSPORT ARE SURMOUNTED BY DCVA AND THE
DIVERGENT POLE OF A CYCLONIC MID TO UPPER-LEVEL JET STREAK OVER THE
SRN PLAINS. GIVEN THE STEEP MIDLEVEL LAPSE RATES...MUCAPE UP TO 1000
J/KG AND STRONG CLOUD-BEARING SHEAR...THE POTENTIAL WILL EXIST FOR
SUPERCELLS CAPABLE OF SEVERE HAIL. THESE SAME PROCESSES ARE EXPECTED
TO MAINTAIN A LOW-PROBABILITY HAIL RISK EWD/NEWD ACROSS NRN MO INTO
CNTRL/ERN IA...AND PERHAPS EVENTUALLY NWRN IL.

..MEAD/SMITH.. 02/20/2014