6/16 – Brittany’s “Heat Advisory” Thursday Morning Forecast

Upper ridge will shift westward over the next several days as troughing digs into New England. Another weak shortwave moving westward around the ridge will have the potential to develop convection during the heat of the day today, with somewhat better areal coverage expected, as precipitable water values increase from 1.8 today to around 2 inches tomorrow afternoon. Forecast convective temperatures are expected to be in the 90 to 95 range tomorrow, which should limit the need for a Heat Advisory.

Only limited focus for convection during the daytime hours Friday and Saturday, with areal coverage much closer to 20 percent during the afternoon hours. The need for a Heat Advisory or Excessive Heat Warning is certainly higher on Friday and Saturday than tomorrow. MEX guidance (GFS based) is a few degrees lower than the ECMWF guidance Friday and Saturday, which looks problematic on Saturday, especially. Current forecast will carry mid 90s both days, and wouldn`t be surprised if Saturday eventually tops out in the upper 90s in some locations.

Saturday night and beyond, upper ridging likely to become focused over the lower Mississippi River Valley from Sunday through the middle of next week, and likely beyond. Areal cover of convection expected to be extremely limited on most days…10-20% and mainly late afternoon. 850 mb temperatures in the 20-22C range argue for highs at least in the mid 90s most days, and possibly a couple degrees higher. Can`t rule out a few spots getting close to 100F, with the most likely day for that probably being next Wednesday. NBM numbers a good bit closer to the ECMWF solution, and appear a bit more reasonable based on the forecast soundings. These readings are well above normal, and several days of advisories/warnings aren`t out of the question. Heat related illnesses would be expected to increase if these trends verify.