Day 4-7 Severe Weather Outlook

…OUTLOOK VALID FROM SUNDAY 7/23 12Z TO THURSDAY 7/27 12Z…

…NO SEVERE WEATHER OUTLINES FORECAST…

…DISCUSSION…

OVER THE 4-7 DAY PERIOD, THE OPERATIONAL GFS AND ECMWF ARE IN GOOD AGREEMENT THAT THERE WILL BE A LOW-PRESSURE SYSTEM TRAVELING ACROSS SOUTHERN CANADA FROM MONDAY THROUGH THURSDAY. THE QUESTION IS THE TIMING OF THE SYSTEM, AS THE LOW SLOWLY MOVES TOWARDS QUEBEC. ALSO, THERE IS SOME AGREEMENT REGARDING A WEAK LOW-PRESSURE SYSTEM OFF THE SOUTHEAST COAST EARLY IN THE WEEK, AS WELL.

THE MODELS ARE SUGGESTING SOME STORM DEVELOPMENT OFF THE SOUTHEAST COAST FOR SUNDAY AND MONDAY, AS WELL AS IN THE UPPER MIDWEST INTO THE GREAT LAKES, MOVING INTO THE MID-ATLANTIC REGION ON TUESDAY. MORE ROBUST STORMS ARE SUGGESTED FOR NEXT WEDNESDAY AFTERNOON, AS THE UPPER-LEVEL RIDGE IN THE PLAINS BREAKS DOWN AND BECOMES A MORE ZONAL FLOW, INCREASING THE SUPPORT IN CONJUNCTION WITH THE LOW MOVING ACROSS SOUTHERN ONTARIO. SUFFICIENT MID-LEVEL LAPSE RATES UP TO 8 DEG C/KM, ALONG WITH 3000+ J/KG SBCAPE AND THE TROUGH SUGGEST THE POSSIBILITY OF SEVERE WEATHER, SO WILL NEED TO BE MONITORED IN LATER OUTLOOKS.

OVERALL, THE SEVERE WEATHER IS A POSSIBILITY DURING THIS PERIOD THROUGH MOST DAYS BUT IS LOW ENOUGH AT THIS TIME TO PRECLUDE ANY OUTLINES FOR THIS FORECAST, INCLUDING A LOW PREDICTABILITY RATE AT THIS TIME.