254
FXCN01 CWHF 061904
FORECAST DISCUSSION FOR OPS AREA ALPHA AND THE ECHOES, CFB HALIFAX
PROPERTIES AND 12 WING SHEARWATER ISSUED BY AVIATION AND DEFENCE
SERVICES OF ENVIRONMENT AND CLIMATE CHANGE CANADA AT 2030Z ON
WEDNESDAY 06 MAY
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KEY FORECAST POINTS:
- WIND GUSTS TO EASE THIS EVENING WITH INCREASED STABILITY
- STRATUS AND PATCHY DRIZZLE OVERNIGHT
- SHOWERS MUSH OF THURSDAY
- RISK OF THUNDERSHOWERS THURSDAY MORNING
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SHORT RANGE DISCUSSION FOR 1800Z 06 MAY TO 0300Z 08 MAY.
MODEL DISCUSSION: USED GDPS /HRDPS
CONFIDENCE: MEDIUM
COMMENTS/IMPACTS: A STRONG SOUTHWEST FLOW OVER THE PROVINCE IS
FORECAST TO WEAKEN TONIGHT AS A TROUGH ORGANIZES TO THE WEST OF THE
REGION. AS THAT TROUGH STRENGTHENS IT BECOMES A COLD FRONT AND PUSH
STRONG SOUTHERLY WINDS, SHOWERS AND RAIN INTO THE REGION WHICH WILL
BECOME AT TIMES HEAVY. THERE WILL ALSO BE A RISK OF EMBEDDED
THUNDERSTORMS WITH THE FEATURE. THE COLD FRONT WILL MOVE THROUGH
DURING THE AFTERNOON, BUT THE WHOLE PRESSURE GRADIENT JUST
COLLAPSES WEST OF THE FEATURE. ALTHOUGH WESTERLY WINDS ARE EXPECTED
BEHIND THE COLD FRONT, THEY ARE NOT EXPECTED TO BE STRONG ENOUGH TO
OVERLY IMPACT ANY POSSIBLE CLEARING TRENDS - AT LEAST THROUGH TO
MIDNIGHT.
LEVEL ONE WIND WARNINGS REMAIN IN EFFECT FOR THE REMAINDER OF THIS
AFTERNOON, AND AGAIN ON THURSDAY MORNING AHEAD OF THE COLD FRONT. A
RAINFALL ADVISORY IS ALSO EXPECTED TO BE REQUIRED FOR AT LEAST 25
MM OF RAIN DURING THE DAY.
LONG RANGE DISCUSSION FOR 0300Z 08 MAY TO 0300Z 11 MAY.
MODEL DISCUSSION: USED GDPS.
CONFIDENCE: MEDIUM.
COMMENTS/IMPACTS: THERE ARE NO SIGNIFICANT CHANGES TO MAKE TO THE
LONG RANGE FORECAST BASED ON THE MODEL RUNS THIS AFTERNOON.
BY FRIDAY MORNING, THE COLD FRONT HAS MOVED OFF TO THE EAST, BUT
THE LOW LEVELS BEHIND THE FEATURE ARE LEFT MOIST AND UNSTABLE. THE
MODELS ARE SHOWING A LOT OF INSTABILITY POPPING UP IN THE AFTERNOON
BUT THE BULK OF THAT IS TO THE EAST OF OUR FORECAST AREA.
SATURDAY HAS BEEN TRENDING SUNNIER ON THE MODELS ESPECIALLY FOR
THE FIRST HALF OF THE DAY. THE OPS AREA RIDES ON THE TOP SIDE OF A
RIDGE EXTENDING NORTHWARD FROM BERMUDA AND THIS GIVES A SOUTHWEST
FLOW. MODELS ARE SHOWING SOME CONVECTIVE DEVELOPMENT DURING THE
AFTERNOON BUT THIS HAS BEEN TRENDING MORE INLAND AWAY FROM THE
SEABREEZE SHADOW.
SUNDAY IS STILL MOIST ON THE CANADIAN MODELS. MODELS ARE SHOWING A
TROPICAL IMPULSE OF MOISTURE MOVING NORTHWARD FROM THE GULF STREAM
IN A MODERATE-STRONG SOUTHERLY FLOW. HOWEVER, SOME OF THE FOREIGN
GUIDANCE IS TRENDING A LITTLE MORE EASTWARD WITH THIS MOISTURE
BLOB. THE FORECAST REMAINS UNCHANGED, BUT STANDS TO BE WATCHED
CLOSELY FOR CHANGES.
END/METOC-HFX
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