Weather Update: Saturday – April 27, 2024

WDEF-TV News 12 Weather Forecast

WDEF-TV News 12 Forecast Discussion

The temperature swings are in “full swing” as we move into the middle of the spring season. Temperatures were well above normal through much of last week, with no dips in the jet stream bringing us some of that still chilly, Canadian air. We will have another day with below normal temperatures to start the work week, with lows in the lower 40’s and highs in the mid to upper 60’s today. Beginning Tuesday, we will be returning to those most pleasant, temperature regimes with lows not too far from 50 degrees and highs remaining in the 70’s, through the rest of the work week. The weekend will be slightly warmer, with lows back in the 60’s and highs in the low to mid 80’s.

Concerning the other elements of the weather forecast, including chances for rain, it appears that most of the News12 viewing area will remain dry this week, despite the passage of a cold front on Wednesday and a warm front Friday into Saturday. Frontal boundaries always have the potential to generate precipitation, but there are times when moisture is limited in advance of these air mass boundaries. This will be the case on Wednesday, as a ridge of high pressure will stick around on Monday and Tuesday over the southeastern United States. The ridge will be so expansive that it will extend from the eastern Seaboard west through the lower Mississippi Valley, through Tuesday night. When these areas of high pressure extend well west through the western Gulf of Mexico into eastern Texas, they limit the amount of moisture that would be advancing north off those warm, gulf waters if these lower atmospheric high pressure systems were not in place. Additionally, fronts generate the strongest atmospheric lift when the air on each side of the boundary collides from nearly opposite directions such as, a northwest wind behind a cold front pushing into warmer air moving from the south or southeast. In meteorological terminology, this is called “convergence”. Convergence along the boundary on Wednesday will be a bit weaker, as winds just ahead of the cold front will be from a more westerly direction; almost due west according to some of the higher resolution, meso-scale computer models.

Therefore, when that cold front builds south across the News12 viewing area on Wednesday, we may see an increase in cloud cover without much, if any rainfall. When the warm front advances north across the Tennessee Valley and southern Appalachian region on Friday, precipitation may be limited once again due to the strength of persistent, low level ridging over the southeastern U.S. and the more westward track of a late week, storm system across the northern Plains and western Great Lakes. Of course, a more westward tracking storm system, such as this late week system which will be associated with a surface low pressure center which crosses the Mississippi River well north, near Minneapolis, may not result in much rainfall over the eastern half of the nation. Alternatively, a storm system with a low pressure center which moves along a path where it crosses the Mississippi River near Memphis, or even farther north near St. Louis, on its way northeast through the eastern Great Lakes, would generate better moisture advection and atmospheric lifting over the eastern U.S., thus providing a better chance for rain across the Tennessee Valley and the beautiful city of Chattanooga.

Stay tuned to our forecasts throughout the week to keep track of any significant changes. We are not doing too badly on precipitation amounts as we move into the middle part of the spring season. Our annual deficit is only around one to two inches however, the rate of evaporation keeps increasing as we move further into the warm season. We may approach a deficit of nearly three inches by early next week, if we remain dry. We will likely have several periods of frontal convection as we move through the month of May. It certainly would be nice to advance through the hot summer months with a rainfall surplus!

The Climate Prediction Center 8-14 Day Outlook for Tuesday, April 30th – Monday, May 6th, features above normal temperatures and above normal precipitation during this period.

National Drought Summary for April 25, 2024

Summary

Moderate to heavy rain amounts fell across parts of the Southeast and Northeast this week, leading to localized improvements to ongoing drought and abnormal dryness in the Southeast, and mostly unchanged conditions in the Northeast, aside from western New York, which missed out on the heavier precipitation and saw minor degradations.

The central third of the contiguous U.S. saw a mix of improvements and degradations, based on where heavier precipitation did or did not fall and where dry and windy conditions continued. Parts of Illinois, Indiana, Ohio, the Michigan Lower Peninsula, southern Missouri and southeast Kansas saw improving conditions after heavier rains fell there. Meanwhile, moderate drought expanded in northwest Missouri and portions of west-central Wisconsin, Minnesota, northwest Iowa, the far southern Michigan Upper Peninsula and far northeast Wisconsin. Much of Texas remained the same, with a few degradations in the southeast corner and several degradations in central and southern Texas where long-term drought conditions are still causing impacts. Recent dryness and warm and windy weather in northwest Oklahoma and the Texas and Oklahoma panhandles led to abnormal dryness developing there.

Short-term dryness and high evaporative demand led to large areas of degrading conditions in northeast Wyoming, while west-central Wyoming, north-central Colorado, northeast Utah, western Montana, and the northern Idaho Panhandle all saw areas of improvement due to lower evaporative demand and improving snowpack recently. In Hawaii, an active trade wind pattern continued, leading to some improvements on the windward (northeast) slopes of the Big Island and Kauai, while a small area of moderate drought developed on the leeward (southwest) portion of Kauai. In Puerto Rico, a few improvements were made where recent rainfall has improved streamflows and crop stress, and lessened rainfall deficits and raised reservoir levels.

No changes were made to the Drought Monitor this week in Alaska.

– NOAA National Centers for Environmental Information

https://droughtmonitor.unl.edu

Severe Weather Safety

Make sure you & your family stay in touch with us. Remember the Storm Team 12 app can always bring you the latest weather alerts for your location as well as Titan Radar. Download it for free from your app store – just search “WDEF Weather”.

The best time to prepare for severe weather is when nothing weather-wise is going on.  Learn more about programming your weather alert radio with WDEF-TV News 12.

\