Current Conditions at Sanborn Field
Monday: Cloudy with scattered rain. High: 62
Monday Night: Cloudy with rain. Low: 48
Tuesday: Cloudy with an afternoon and evening chance for thunderstorms. High: 76
Tuesday Night: Showers and Thunderstorms. Low: 56
Thanks to IconArchive.com for the icons!
=================================================================
Discussion:
While mid-Missouri saw a warm and pleasant day yesterday, things are about to change as we jump into this week. Showers and thunderstorms are expected today, Tuesday, and Wednesday, where some of these thunderstorms could be strong to severe, due to a low pressure system moving in from the west. All forms of severe weather will be possible Tuesday afternoon and evening, going into Wednesday. The Storm Prediction Center, SPC, has put mid-Missouri in a slight risk for severe weather, where we may see heavy rain, hail, damaging winds, and tornadoes. Otherwise, temperatures should stay fairly seasonal throughout the first half of the week. Make sure to remain weather aware this week, especially Tuesday!
-Gromada
=================================================================
Forecasters: Baker, Gromada
Date Issued: 04/11/2022 10:00AM CDT
For this forecasting shift, NAM was the model of choice as it had a better handling of the occluded low over the upper Great Lakes area as well as the low pressure system setting itself up over the Rockies. There are multiple concerns for this forecast period as the cold front associated with the Great Lakes low will stall over the Mason-Dixon Line this afternoon promoting flooding potential. Another concern follows right behind as a low pressure system pushes eastward starting Tuesday. As this system progresses across the Central Plains into the lower Mississippi Valley, a dry line stretching across central Texas will keep dew points low; however, a deep layer of shear combined with strong ascent and low level convergence could aid strong thunderstorm potential with tornadoes very much a possibility.
Mid-Missouri is waking up to post-frontal sprinkles as the cold front that moved through the area continues to push southeastward Monday morning. This cold front is associated with an occluded low located over the Great Lakes. This deep layer of moisture eventually pushes east with the rest of the system; however, moisture returns ahead of the strengthening Northern Plains low evident on the 750-mb relative humidity map. However, severe weather threats today should not be ruled out for southeastern Missouri and the southeastern US as the cold fropa stalls and better instability and shear is evident over the central Arkansas region later this afternoon.
Short wave ridging will continue Tuesday ahead of another large system. A deepening Colorado Low will move across the Central Plains Tuesday. A warm fropa stretching from the Rockies low down through Texas will push northward and will surge the Central Plains and Midwest with warm, moist, and unstable conditions. These conditions are evident on the 500-mb vorticity map as all lift and spin associated with the Great Lakes low progresses with the system as it moves east; however, values begin to increase again associated with a progressing low over the Northern Plains and Upper Mississippi Valley. These two systems promote spin over the Midwest Tuesday at 18Z.
Another big concern for this week is low-level convergence. As evident on the 250-mb divergence map, upper level divergence moves over mid-Missouri Wednesday about 12Z. This band of divergence assisted by the jet stream will flow across central Iowa and northwest Missouri Wednesday morning. High values of upper level divergence highlight surface convergence and ultimately more lift to promote the system. Along with powerful surface convergence, the 850-mb wind map is very telling. After Monday's frontal passage, winds progress to a southerly flow starting Tuesday around 12Z. This is due to a strengthening southwest LLJ. This LLJ picks up to 50-60kts winds starting 00Z Tuesday. This LLJ will promote a deep layer of shear with moisture values increasing ahead of the LLJ. These components alone are enough to raise flags as thunderstorm development is quite high with these conditions. Not only should hail not be ruled out, but a few tornadoes could stir up due to these conditions.
As these conditions raise an eyebrow to severe weather concerns, multiple sounding were analyzed to determine to severity of this system. A slight dry out of the upper layers is evident Monday morning; however, the profile moistens up quickly following the dry out and bringing rain back to mid-Missouri by Monday afternoon. Another dry out of the upper layers is seen throughout Tuesday; however, the lower levels stay quite saturated as it is being aided by the LLJ. The sounding then draws eyes starting 20Z Tuesday. LI of -9 provides the forecaster with a strong severe weather potential. The KI index of 20 highlights that thunderstorms/heavy rainis possible. These are quite high confidence values to support a strong convective system; however, values of up to 4000 J/Kg-1 CAPE with weak CIN values really show the potential for severe weather. These large values are enough to promote thunderstorm activity with large hail and tornadoes possible. The last index to be evaluated would be the TT at 58. A TT of 58 validated thunderstorms likely, with tornadoes possible.
Sprinkles of rain will be possible Monday afternoon as the system exits our region. Rain totals for Monday should not exceed more than a trace to .05''. With a break in the rain Tuesday, accumulations will be pick back up as another system pushes through bringing rain total amounts to a quarter to half an inch on both Tuesday and Wednesday.
-Baker
No comments:
Post a Comment