textproduct: Columbia

WHAT HAS CHANGED

Aviation discussion updated for 12z TAF issuance.

KEY MESSAGES

- 1. High confidence in above normal temperatures over the next several days.

- 2. Limited rain chances early this week. However, a pattern shift mid to late week may lead to increasing rain chances into next weekend.

DISCUSSION

Key Message 1: High confidence in above normal temperatures over the next several days.

Confidence remains high in the temperature forecast over the next week, as offshore high pressure takes center stage and keeps our weather fairly benign. Upper troughing in the west will force amplification of the ridge over the eastern CONUS over the next several days as the storm track remains well to the north. In response, increasing heights and thicknesses will lead to above normal temperatures for mid-May with highs in the low 90s through at least Wednesday. The offshore high will also remain quasistationary, and southerly flow should continue to feed a steady stream of moisture into the region with dewpoints in the low to mid 60s much of the week.

Key Message 2: Limited rain chances early this week. However, a pattern shift mid to late week may lead to increasing rain chances into next weekend.

Rain chances will remain on the lower end over the next few days. One caveat remains this afternoon, with hi-res guidance showing a few showers and thunderstorms encroaching on the CSRA; mainly our GA counties. This threat still appears to be low, with model soundings generally showing at least a sliver of capping between H85 and H7. That said, any parcels that are able to punch through cap will have plenty of instability to work with. Weak winds will lead to slow storm motions, and a few strong wind gusts can't be ruled out as DCAPE values exceed 1200 J/kg. Confidence remains low, however a shower or thunderstorm cannot be completely ruled out. Monday, Tuesday and most of Wednesday then remain rain-free, before we turn our attention to a slow moving front which may arrive late Wednesday. This boundary, along with better moisture (PWAT values between 1.5" ad 1.8") and a couple weak shortwaves may bring an increase in rain chances lasting Thursday into the upcoming weekend.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

VFR conditions for much of the TAF period except for a brief period of possible stratus around daybreak.

High pressure anchored over the western Atlantic is resulting in southeast/southerly low level flow with moisture already increasing across the region. With the onshore flow of Atlantic moisture advection, some stratus has developed and should persist for another few hours at the terminals with some CIG restrictions. A 20-25 knot low level jet should keep any VSBY restrictions minimal. CIGS return back to VFR mid to later morning, and surface winds are expected to increase from the south after 14z up to 07-10 knots by 17z. Some afternoon cu are possible given strong heating, and another round of stratus will be possible tonight as winds decouple back to light and variable or calm.

EXTENDED AVIATION OUTLOOK...Increased moisture may result in brief restrictions at the terminals due to low clouds and/or fog each day this week. Rain chances increase towards the end of next week.

CAE WATCHES/WARNINGS/ADVISORIES

SC...None. GA...None.