562
FXCN01 CWHF 301847
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
TUESDAY 30 JUNE
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KEY FORECAST POINTS:
- STILL A MODERATE RISK OF SHOWER AND SMALL RISK THUNDERSHOWER THIS
EVENING.
- SMALL RISK OF STRATUS AND MIST OVERNIGHT
- CONDITIONS DETERIORATE ON CANADA DAY
- VARIABLE WEATHER FOR THE END OF THE WEEK
===================================================================
SHORT RANGE DISCUSSION FOR 1800Z 30 JUNE TO 0300Z 02 JULY.
MODEL DISCUSSION: USED HRDPS
CONFIDENCE: MEDIUM
COMMENTS/IMPACTS: THE HIRES AND RDPS MODELS NAILED THE CLOUD
DEVELOPMENT THIS AFTERNOON ALONG THE COASTLINE AS THE WIND
CONVERGENCE FORCES THE VERTICAL DEVELOPMENT. SHOWERS AND
THUNDERSHOWER DEVELOPMENT IS EXPECTED TO WANE EARLY THIS EVENING AS
THE AREA LOSES THE WIND CONVERGENCE.
AFTERWARD THE AREA IS LEFT IN SCATTERED TO VARIABLE CLOUD
CONDITIONS AS CLOUDY BITS SPILL INTO THE MARITIMES FROM A
NORTHEASTERN ONTARIO WARM FRONT. THERE IS NOT MUCH STRATUS NEAR THE
NS COASTLINE AT ISSUE TIME, BUT IF SOME SHOWER ACTIVITY
MATERIALIZES, THAT LITTLE BIT OF ADDED MOISTURE TO A HUMID AIRMASS
COULD BE ENOUGH TO INITIATE LOW CLOUD DEVELOPMENT.
MODELS ARE A LITTLE BIT SLOWER IN BRINGING IN SHOWER ACTIVITY ON
CANADA DAY, AND HAVE WEAKENED THE AREA OF PRECIPITATION WHEN IT
REACHES HALIFAX. DESPITE THIS, THERE IS STILL SOME EXPECTED SHOWER
ACTIVITY TO MOVE IN IN THE AFTERNOON, AND WITH THIS COMES LOWERING
CEILINGS AND A HIGHER RISK OF STRATUS AND MIST DEVELOPMENT. 24
HOURS AGO, I WOULD HAVE ALMOST WIPED OUT ANY CHANCE OF HALIFAX
FIREWORKS CANADA DAY NIGHT, HOWEVER, TODAY WITH THE DECREASE IN
PRECIPITATION AND THE GIVEN WIND FLOW, THAT IS NOT STRAIGHT
SOUTHERLY, CHANCES OF SEEING FIREWORKS HAVE INCREASED.
LONG RANGE DISCUSSION FOR 0300Z 02 JULY TO 0300Z 05 JULY.
MODEL DISCUSSION: GDPS
CONFIDENCE: MEDIUM
COMMENTS/IMPACTS: THERE HAVE BEEN CHANGES IN THE PROJECTED SYNOPTIC
PATTERN FOR THE LONG RANGE DAYS. HOWEVER, THERE IS CONFLICTING
INFORMATION ON WHETHER THESE CHANGES ARE WARRANTED AT THIS TIME.
THERE IS A MOTHER-LOW ANCHORED NEAR JAMES BAY ON THURSDAY WHICH
SLOWLY DRIFTS TOWARD LABRADOR FOR FRIDAY AND INTO NEWFOUNDLAND ON
SATURDAY. SOME TROUGHING ROTATES AROUND THIS FEATURE. ONE SHOT OF
SHOWERS AND THUNDERSHOWERS MOVES THROUGH THURSDAY MORNING AND IS
NOT TOTALLY REFLECTED IN THE WORDED FORECAST. ANOTHER SUCH TROUGH
IS SHOWN BY THE MODEL ON FRIDAY MORNING, AND AGAIN IS NOT EASY TO
REFLECT THIS IN THE FORECAST. BEHIND THIS TROUGH, MODELS ARE NOW
SHOWING A NORTHWEST FLOW, WHICH SHOULD ALLOW FOR HALIFAX
TEMPERATURES TO SOAR. ON SATURDAY, A BROADER TROUGH FROM THE GULF
OF ST. LAWRENCE IS FORECAST TO SWING THROUGH, SHIFTING TO THE FLOW
TO THE NORTH. THIS LOWERS THE HIGH TEMPERATURES BUT INCREASES THE
SHOWER CHANCES.
END/METOC-HFX
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