Monday, May 11, 2015

Keep an Umbrella Handy This Week

By Jay Grymes & Steve Caparotta

May 11th First Alert Quickcast:

- a wetter looking week ahead
- goodbye Ana!

A squall line rolling out ahead of a slowly advancing cold front delivered some strong storms to the northern portion of the WAFB viewing area during the early and mid afternoon hours. The storms came with locally-heavy downpours, frequent cloud-to-ground lightning and indications of hail on the order of 1” or more in diameter for a few spots. The active storms prompted the NWS to issue a handful of Thunderstorm Warnings for more than a half-dozen parishes and counties, in addition to a Tornado Warning for parts of Livingston and Tangipahoa parishes. As of this writing there have been no confirmed touchdowns in our viewing area although we did receive one report from a viewer of a funnel near the Holden area close to Warning time.

The stormy weather has passed and as we head into the evening the rains continue to taper off. We expect most, if not all, of the showers to have ended by the mid to late evening hours with a mainly-dry night ahead. However, we’ll remain under mostly cloudy skies, the air will remain rather muggy, and the damp air and wet ground should allow for the onset of at least some patchy fog. 

Tuesday morning will open with clouds, patchy fog, maybe a spotty shower and a muggy air mass with temperatures near 70° for metro Baton Rouge. We expect mostly cloudy skies through the morning, with rain chances on the rise as we head into mid-day. By the afternoon, we’re calling for a 50% to 60% rain chance across the viewing area. We could see one or two strong storms during the afternoon and can’t exclude the possibility of a Warning, but the threat for severe storms is certainly lower for tomorrow. With the cloud and rains, we’re expecting highs to top out in the mid 80°s for most WAFB neighborhoods.

The cold front that generated today’s squall line will sag southward into the southern parishes but then there for Tuesday and Wednesday before retreating to the north as a warm front. So don’t expect any relief from the humid Gulf air mass that has dominated our weather for the past couple of weeks.

While Tuesday looks rather wet, our forecast for Wednesday is considerably drier, with only a 20% to 30% chance of afternoon rains. For Thursday, we’ll ease the rain chances back to 40%, then return to 50% to 60% for Friday. Plan for mostly-dry but muggy mornings in the upper 60°s to near 70° for metro baton Rouge with patchy morning fog through the week. Highs will hover in the mid to upper 80°s, largely dependent on cloud cover and rain chances.

For the weekend, we’ve got scattered rains currently on the forecast board for Saturday with isolated-to-scattered rains for Sunday, with highs for both days in the upper 80°s.

As for T.D. Ana, the NWS Weather Prediction Center (WPC) has issued its last advisory as of 4:00pm this afternoon. Ana will continue to accelerate to the northeast while skirting the U.S. Mid-Atlantic Coast tonight. The WPC projects that Ana will be absorbed by an advancing cold front -- currently located to Ana’s west -- sometime tomorrow.

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