Thursday, April 30, 2020

Thursday Night - Mostly clear. Low: 46-50

Friday - Increasing clouds. High: 74-78

Friday Night - Partly cloudy. Low: 56-60

Saturday  - Mostly sunny. High: 80-84

Sunday - Cloudy, rain possible. High: 70-74

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Mostly clear skies will continue Thursday night with temperatures falling to near average. Southerly winds will return Friday morning allowing for warmer air to move into Columbia, along with the transport of moisture from the Gulf of Mexico. This moisture will cause clouds to develop and spread across Missouri. Mostly sunny skies will return Saturday with above average temperatures in the low 80’s. This will be the best day in the forecast, so be sure to get outside and enjoy. Clouds are expected to develop Saturday night into early Sunday, bringing the possibility of rain throughout the day. CD
Forecasters: Lieberman, Dowell, Ritter
Issued:  5:oopm: April 30, 2020.
Technical Discussion (The nerdy stuff we are discussing in class)

We used the GFS and NAM supplemented with SREF and GEFS. The model diagnosis from the WPC recommends a general model blend for this forecast. CD
Taking a current look and beginning with 250MB, there is a jet max located over the east coast stretching from Georgia to Quebec with a value of 110 knots. This leaves Columbia in the convergence entrance region. There is a deep, near neutral trough extending south from Ontario to the Gulf of Mexico. At 500MB, the trough is still existing in the same area. However, there is a second jet max over the Mississippi River valley with values near 100 knots. At 700MB, there is a large swap of moisture from the southeastern Gulf of Mexico extending up the east coast into Quebec. The moisture also wraps back to a large area of circulation over the Michigan/Indiana/Ohio border. Finally, at the surface, there is a low-pressure system over southern Michigan with a cold front sprawling from Pennsylvania to the eastern Gulf of Mexico. CD
Thursday was influenced by a high pressure system bringing the bright blue sunny skies. Mostly clear skies will remain Thursday night with northerly winds. Temperatures will drop near average with a low in the upper 40s to near 50. CD
The trough to the east and ridge to the west result in northerly flow that will continue to bring dry continental air aloft tonight. However, as the ridge axis passes over Missouri, flow will become more zonal. Friday, at 850MB, a low level jet max is strengthening and moving toward Missouri as well. This is advecting moisture into the area Friday throughout the day as we open to the Gulf. The result is increasing clouds.
Friday night, zonal flow will resume. Moderate clouds and slight WAA continuing into the night will result in warmer temperatures than the night before. Saturday morning, primarily westerly flow will bring dry air parcels that have tracked through the southwest. Mostly sunny skies allow for radiational heating and a warmer day than before.
Saturday evening and night, a 250MB jet max over the the Great Lakes puts Missouri in the right entrance region. This jet has a particularly strong wind speed gradient over the Greater Missouri area. This induces rotation at 500MB and UVM in the lower levels. Additionally, 850MB flow shows saturated parcels traveling from the Gulf, through eastern Mexico into the midwest. This may provide sufficient moisture for precipitation Saturday night into Sunday. Convection seems to be of some concern as well. CAPE values exceed 2500J/Kg on some soundings and SREF plumes show a mean of 1700J/Kg. K index and LI show peak values of 37 and -8 respectively on NAM soundings. However, these are limited to the evening and the convective temperature remains fairly high. CIN values also indicate strong capping. For this reason initiation is questionable. In terms of stratiform precipitation, soundings show significant UVM and shallow saturation between 700-900MB around 00Z on Sunday. This mostly decreases from then on with subsequent time steps inspiring little confidence for sustained precip. SREF plumes indicate small quantities of rain are likely but members are in disagreeance on times and quantities. Two members show close to an inch but the mean is around a quarter inch. Scattered, light precip seems possible. Future forecasters should monitor the situation and the possibility for convection.

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