textproduct: Columbia

WHAT HAS CHANGED

Forecast confidence regarding above normal temperatures and the next chances for rain remain on track. Aviation discussion updated for 06Z TAF issuance.

KEY MESSAGES

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

- 2. A pattern shift mid to late week may lead to increasing rain chances into this weekend.

DISCUSSION

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

Confidence remains high in the temperature forecast through at least Wednesday. Upper troughing in the west will keep the ridge amplified over the eastern CONUS over the next several days. The resulting south to southwesterly flow into the middle of the country will keep moisture anomalies and the storm track out of our region. In response, increasing heights and thicknesses across the southeast will bring above normal temperatures for mid-May, with highs in the low 90s through at least Wednesday. The offshore Bermuda high will also remain quasistationary, and south to southeasterly flow should continue to feed a steady stream of low level moisture into the state with dewpoints in the low to mid 60s much of the week. This shallow moisture will also make daily fair-weather cu and overnight stratus a part of diurnal trends over the next several days.

Key Message 2: A pattern shift mid to late week may lead to increasing rain chances into this weekend.

Dry conditions are expected to prevail through Wednesday with the stagnant pattern and PWATS generally near or perhaps slightly below normal levels. Late in the week, generally from Thursday onward, some weakness in this pattern will allow a few disturbances to track through the TN valley and slightly increase PWAT values in our area to between 1.25" and 1.7". Latest guidance keeps the best moisture transport to our west, but this slight shift in the pattern may bring an increase in rain chances lasting Thursday into the upcoming weekend. Details regarding the best timing and potential rainfall amounts will continue to come into better focus over the next several forecast packages.

AVIATION /06Z MONDAY THROUGH FRIDAY/

VFR conditions generally expected with brief restrictions possible again this morning.

Satellite imagery showing mainly convective debris cirrus clouds over the region. Generally south to southeast winds around 5 knots should gradually wane to less than 5 knots during the predawn hours. Abundant low level moisture in place will set the stage for another round of possible predawn stratus/fog. Guidance continues to indicate a brief period of stratus developing during the 08-10z time frame across the eastern Midlands and spreading northwestward possibly impacting all terminals. Will continue to show VFR prevailing conditions with tempo to IFR cigs and vsbys 09z-13z. Any restrictions should return to VFR by 14z with southerly winds picking up through the day to around 5 to 7 knots by 15z and closer to 10 knots after 21z. Little chance for any convection on Monday given strengthening upper ridging.

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.