Forecast Discussion: Friday, August 18th, 2017

Written By Chase Graham

SHORT-TERM FORECAST: FRIDAY AND THE WEEKEND

In advance of a "cold" front on Friday, our area will be plagued with another day of high heat and humidity, with dew point temperatures remaining in the low-to-mid 70s during the middle of the afternoon. As a result of plentiful surface moisture in combination with adequate upper-level forcing brought on by the front, showers and thunderstorms should form along the mountains by early afternoon tomorrow, similar to the setup that we've had the past few days. Once the cold front moves through the area early Saturday morning, drier air should move into the area as light westerly winds will help to keep dew point temperatures in the mid-to-upper in the 60s on Saturday afternoon. This, in conjunction with postfrontal subsidence behind the cold front will hinder the development of showers and thunderstorms on Saturday and Sunday afternoon, although the chance of storms cannot be completely ruled out. Unfortunately, the cold front will not bring cooler temperatures to our area, as highs should remain in the upper 80s and lower 90s throughout the weekend.  

2-meter Dew Point Temperatures, Friday, Aug. 18th, 2:00 p.m.           Source: tropicaltidbits.com

2-meter Dew Point Temperatures, Friday, Aug. 18th, 2:00 p.m.           Source: tropicaltidbits.com

2-meter Dew Point Temperatures, Friday, Aug. 18th, 2:00 p.m.         Source: tropicaltidbits.com

2-meter Dew Point Temperatures, Friday, Aug. 18th, 2:00 p.m.         Source: tropicaltidbits.com

A LOOK AHEAD TO THE "GREAT AMERICAN ECLIPSE": MONDAY

By Monday, humidity will begin to increase again, as a moist southerly wind will assist dew point temperatures in possibly reaching 70 by the afternoon. This could allow for some convection to form, particularly to our south in Georgia and the South Carolina lowcountry. Clouds (in relation to eclipse viewing quality) is possibly the most difficult thing to forecast, because one small cloud in the wrong place at the wrong time could totally spoil viewing the eclipse. As a result, I will refrain from making any sort of prediction with certainty about eclipse viewing. All I will say for now (just after midnight on Friday morning) is that conditions look moderately favorable for eclipse viewing next Monday in our area.

Current Model (GFS/American) Cloud Cover Prediction, 2:00 p.m. 8/21/17 Source: tropicaltidbits.com

Current Model (GFS/American) Cloud Cover Prediction, 2:00 p.m. 8/21/17

Source: tropicaltidbits.com

LONG-RANGE FORECAST: TUESDAY THROUGH THE REST OF NEXT WEEK

After the excitement of the eclipse next Monday, we will return to the typical hot and humid pattern that we have experienced over the past week for Tuesday, Wednesday, and Thursday next week. Shower and thunderstorm chances will increase as we get closer to next weekend, as a stronger cold front approaches from the north. Both major long-range models (GFS and Euro) suggest that there will be some type of cold front moving into our area by the end of next week. The GFS has a more moderate air mass moving into the area while the Euro wants to bring a more significant cool air mass into the southeast. Regardless, it looks probable that a cooler and dry air mass may be on the way for next weekend.

Synoptic Setup for the middle of next week (Model: European/ECMWF)                                       Source: Accuweather Professional

Synoptic Setup for the middle of next week (Model: European/ECMWF)                                       Source: Accuweather Professional

Synoptic Setup for late next week. Note the "valley" created in the geopotential height lines. This indicates a "trough", which generally brings cooler weather.  (Model: European/ECMWF)                                                                         Source: Accuweather Professional

Synoptic Setup for late next week. Note the "valley" created in the geopotential height lines. This indicates a "trough", which generally brings cooler weather. 

(Model: European/ECMWF)                                                                         Source: Accuweather Professional