CONVECTIVE FORECAST
VALID 06Z MON 14/04 - 06Z TUE 15/04 2003
ISSUED: 13/04 20:13Z
FORECASTER: GROENEMEIJER

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN SPAIN

GENERAL THUNDERSTORMS ARE FORECAST ACROSS IBERIA, SOUTHERN FRANCE, SOUTHEASTERN BALKANS, AEGEAN SEA AREA, TURKEY

SYNOPSIS

A LARGE RIDGE IS PRESENT OVER WEST EUROPE. AN NW-SE ORIENTED UPPER TROUGH IS AMPLIFYING. A STRONG SOUTHERLY JET STREAK ON ITS EASTERN FLANK IS LOCATED OVER EASTERN IBERIA AND PROGRESSING NORTHWARD. UPPER-LOW EXPECTED TO CUT-OFF FROM TROUGH OVER SOUTHEASTERN IBERIA NEAR END OF THE FORECAST PERIOD. ANOTHER UPPER LOW IS PRESENT OVER THE SOUTHEASTERN BALKANS CAUSING RELATIVLY STEEP LAPSE RATES AND MAINTAINING SOME THUNDERSTORM ACTIVITY.

DISCUSSION

...EASTERN SPAIN...
A MESOSCALE LOW-PRESSURE SYSTEM IS ANALYZED OVER NORTHERN ALGERIA SUNDAY 18Z. IT IS FORECAST HAVE MOVED QUICKLY NORTHWARD TO JUST WEST OF EAST-CENTRAL SPAIN NEAR 12Z AND THEN REMAIN ALMOST STATIONARY. AN EASTSOUTHEASTERLY LOW-LEVEL JET WILL FORM NORTH OF THE CYCLONE. THERE WILL BE STRONG MOISTURE ADVECTION INTO THE EBRO VALLEY THIS NIGHT AND TOMORROW MORNING. LOW-LEVEL JET WILL ASLO PROVIDE STRONGLY VEERING WINDS WILL BE THE RESULT. IF THERE IS ENOUGH SOLAR HEATING, SLIGHT INSTABILITY /A FEW HUNDERDS OF J/KG MLCAPE/ WILL BUILD, YIELDING A POTENTIAL FOR SUPERCELLS, ESPCIALLY IN THE EBRO VALLEY AREA, BUT POSSIBLY ALONG THE EAST COAST AS WELL. EXPECT A FEW SUPERCELLS TO FORM DURING THE AFTERNOON WITH A CHANCE OF LARGE HAIL, STRONG WIND GUSTS AND POSSIBLY TORNADOES. GREATEST CHANCE OF TORNADOES IS NEAR THE COAST, WHERE LCL HEIGHTS ARE EXPECTED TO BE THE LOWEST. DURING THE EVENING MORE CONVECTIVE ACTIVITY IS EXPECTED TO FORM OFF-SHORE THAT WILL CLUSTER WITH THE CONTINENTAL CONVECTION TO FORM AN EXTENSIVE MCS. THIS MCS WILL REMAIN ALMOST STATIONARY AND PRODUCE VERY HIGH RAINFALL AMOUNTS IN THE AREA OVERNIGHT AND ON TUESDAY.

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