132  
FXCN01 CWHF 090810  
 
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 0830Z ON  
WEDNESDAY 09 JULY  
 
===================================================================  
KEY FORECAST POINTS:  
 
- A LOW CONFIDENCE CLOUD FORECAST FOR TODAY AND THURSDAY.  
- WINDS EXPECTED TO STAY UNDER 15 KNOTS FOR TODAY AND THURSDAY BUT  
STAY GENERALLY ONSHORE.  
- LOW CONFIDENCE FORECAST OF SHOWERS ON FRIDAY.  
- IMPROVEMENT FOR SATURDAY AND SUNDAY.  
 
===================================================================  
SHORT RANGE DISCUSSION FOR 0600Z 09 JULY TO 0300Z 11 JULY.  
MODEL DISCUSSION: USED A BLEND OF THE MODELS  
CONFIDENCE: MEDIUM-LOW.  
COMMENTS/IMPACTS: SYNOPTICALLY THERE IS NOT MUCH TO HANG THE  
FORECAST ON FOR THE NEXT TWO DAYS. GENERALLY THERE IS WEAK  
TROUGHING SOUTH OF NS AND WEAK RIDGING TO THE NORTH. DRIER AIR IS  
TRYING TO PUSH INTO HALIFAX FROM THE NORTH, BUT THERE IS A  
STRUGGLE WITH THE ONSHORE WINDS AND THE ABUNDANT MOISTURE OVER  
SOUTHERN NOVA SCOTIA. THE MODELS ARE STRUGGLING WITH THE  
PREDICTION OF HOW FAR SOUTH THE CLOUD WILL PUSH AND CURRENT  
SATELLITE IMAGERY IS NOT HELPING IN PREDICTING WHAT WILL HAPPEN.  
THE PREDICTED TREND IS THAT THE DRIER AIR WILL WIN FOR A WHILE,  
AND SOME SUN WILL BREAK THROUGH FOR TODAY.  
TONIGHT, THE TROUGH FROM THE SOUTH NUDGES NORTHWARD AND MID CLOUD  
SPILLS INTO THE REGION AND THEN THE LOW LEVELS MOISTEN UP  
OVERNIGHT. HI RES MODELS ARE SHOWING STRATUS AND FOG REDEVELOPING  
ALONG THE IMMEDIATE COAST AND THIS IS ENTIRELY PROBABLE.  
ON THURSDAY, THE TROUGH CONTINUES ITS SLOW NORTHWARD PUSH. MODELS  
ARE SHOWING CLOUD COVER FOR THE DAY NOW, AND THE HI RES EVEN HAS  
SHOWERS PUSHING OVER THE MAINLAND LATER IN THE DAY. THE FORECAST  
WILL BE FORCED TO BECOME MORE PESSIMISTIC AS A RESULT.  
 
LONG RANGE DISCUSSION FOR 0300Z 11 JULY TO 0300Z 14 JULY.  
MODEL DISCUSSION: USED A MODEL BLEND  
CONFIDENCE: LOW-MEDIUM BUT IMPROVING ON THE WEEKEND.  
COMMENTS/IMPACTS: A WEAK LOW PRESSURE SYSTEM TRACKS SOUTH OF NS ON  
FRIDAY. THE MODELS HAVE BEEN WAFFLING ON AND OFF ABOUT PUSHING RAIN  
OVER NS. TONIGHT, THEY'RE ARE ABOUT HALF AND HALF. THERE IS A TROF  
OVER NB AND THE MODELS ARE STRUGGLING WITH HOW MUCH TO LINK THE  
MOISTURE FROM THESE TWO SYSTEM TOGETHER. IT SEEMS PRUDENT TO  
MAKE THE SHOWER FORECAST MORE POSITIVE BASED ON THE LATEST MODEL  
TRENDS.  
ON SATURDAY, THE WEAK TROF LINGERS IN MAINE AND NB WHILE THE LOW  
MOVES OFF TOWARD NEWFOUNDLAND. THIS ALLOWS A LIGHT NORTHWEST FLOW  
OF SOMEWHAT DRIER AIR TO MOVE INTO THE OPS ZONE. BUT THE AIRMASS  
REMAINS UNSTABLE, SO A CLOUD SUN MIX IS THE BEST FORECAST I CAN  
OFFER AT THIS TIME. IT REMAINS UNSTABLE AS WELL, SO THERE IS A  
CHANCE OF SHOWERS WITH THE CLOUDS.  
ON SUNDAY, A SURFACE RIDGE STRENGTHENS OVER THE MARITIMES, SO MORE  
SUNSHINE SHOULD FINALLY DEVELOP.  
 
END/METOC-HFX  
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