Wednesday, May 15, 2019

The Mizzou CWF is currently on break and will return June 3rd for regular weather forecasts and updates.

Monday, May 13, 2019

Monday -  Mostly sunny. High: 64-68

Monday Night -  Mostly clear. Low:44-48

Tuesday -  Mostly sunny. High:70-74

Tuesday Night -  Isolated showers and thunderstorms. Cloudy. Low: 60-64

Wednesday -  Clouds clearing in the morning becoming mostly sunny. High: 78-82 

Thanks to for the icons!

The cooler temperatures remain for Monday, but that will change going forward this week. Today, high pressure dominates mid-MO giving us plenty of sunshine for the next 24-36 hours. By Tuesday night, showers and thunderstorms will develop across the region along a warm front but will move out by Wednesday morning. After this warm front passes, temperatures will be some the warmest temperatures we've seen this year as 80s are in the forecast.

Forecasters:  Hirsch
Issued: 11:30 a.m.; 13 May 2019

Technical Discussion (The nerdy stuff we are discussing in class!)
The main issue for this forecast period is the temperatures and potential for rain on Tuesday night. WPC recommended a general model blend so have used the 12 Z GFS for this forecast period. 

At the start of the forecast period a surface anticyclone is situated over MO which will shift off to our east over the next day and half. The high pressure will allow for calm conditions with little moisture in the region allowing for plenty of sunshine. As it moves east, Columbia shifts to a southerly flow which will  allow for WAA leading to clouds developing late afternoon/early evening on Tuesday. The moisture will prove important as a low currently in N. Dakota shifts south and east into central Iowa where a warm front will develop and move through between 00 Z and 09Z. This area will prove the initiation spot for showers and thunderstorms. The reason for thunderstorms will be due to this dynamic lifting, which is weak with omega values of -6 mb/s at its strongest point. CAPE is also about 700-1000 J/kg allowing for some thunderstorms to develop.  The front will slowly clear out during the day and with the frontal passage, temperatures will quickly warm up and stay that way for the remainder of the week as 80s are likely.

Friday, May 10, 2019

Friday Night - Overcast. Low: 46 - 50.

Saturday - Mostly cloudy with showers likely. High: 56 - 60.

Saturday Night - Overcast with isolated drizzle. Low: 44 - 48. 

Sunday - Partly Cloudy. High: 62 - 66.

Monday - Mostly sunny. High: 66 - 70.

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​Cloudy skies will prevail for most of this weekend. You will need your umbrella for showers Saturday morning into the after afternoon. We expected precipitation totals not to be greater than 0.30 inch. By Sunday afternoon should be able to see some peaks of sunshine as some of the clouds have moved out. Clouds completely move out overnight allowing for a sunny start to the week. With the sunshine we can expect warmer temperatures in the upper 60s for Monday.


Forecasters: Johnston & Rojas

Issued: 6:15 p.m.; 10 May 2019

Technical Discussion (The nerdy stuff we are discussing in class!)

We used the 12Z GFS to forecast due to the Weather Prediction Center having an average confidence in a non 12Z CMC model blend.

At 250-mb we are located in the right entrance of the jet streak with some related divergence. Looking at 500-mb we are located below the downstream side of the trough with maximum vorticity circulation over our area at 09Z on Saturday. The relative humidity at 700-mb increases to near 80% by the following 3 hours. At this same time omega values are around -3 ub/s. Showers likely from early in the morning on Saturday until the afternoon. Vorticity advection would be the main factor to yield forcing for upward motion based on the convergence of Qs vector. We expect low amount of total precipitation from these showers with the mean GEFS plumes line reaching 0.2 inch and GFS with 0.28 inch.

Soundings from 18Z on Saturday to 00Z on Sunday show temperature and dew point profiles really close near the surface while profiles in upper atmosphere becomes saturated, which will lead to cloudiness being present and isolated drizzle possible.

By Sunday a clipper system would be to our north over Iowa by 15Z on Sunday. The axis of the positive tilted trough at 500-mb will cross over our area by the afternoon with associated maximum vorticity circulation. The next period of isolated precipitation would be at 15Z on Sunday due to the vorticity advection mentioned and divergence at 250-mb. After 15Z the atmosphere dries out which could inhibit this opportunity of precipitation and provide some clearing. Sunday night the southwesterly winds slowly shift westerly as the system is moving out of the area and a well amplified ridge start to dominate the western 2/3 of CONUS aloft and a high pressure system at surface. The atmosphere will dry out by Monday leaving us sunny conditions for the beginning of next week.

Thursday, May 9, 2019

Tonight - Clouds begin to clear. Low: 40-44

Friday - Mostly sunny with clouds building in in the afternoon. High: 62-66

Friday Night - Overcast with showers later in the night. Low: 40-44

Saturday - Mostly cloudy with morning showers.  High: 56-60

Sunday - Overcast with small isolated showers.  High: 62-66

Thanks to for the icons!

Don't retire those umbrellas just yet, more rain is on the way this weekend! Tonight brings a break in the clouds with a calm night and milder temps through tomorrow morning. Friday brings similar conditions to Thursday as clouds begin to build back in ahead of the incoming cold front Friday night. Showers will take form in the latter hours of Friday night through Saturday morning with rain totals hovering just around a quarter of an inch. Temps cool off a bit with the rain and cloud coverage, but winds will stay calm and breezy. Clouds remain prominent through the later hours of Saturday with another chance for rain coming Sunday. Right now rain totals for Sunday sit in trace amounts under a tenth of an inch with a low pressure system looming over the Great Lakes to Missouri's NE. Hopefully the later days of May can keep the clouds away!

Forecasters: Doll, Myers and Bongard
Issued: 4:20 p.m.; 9 May 2019

Technical Discussion (The nerdy stuff we are discussing in class!)

Mid Missouri finally sees a break for rain tonight.  At 250-mb, southwesterly flow is continuing to bring moisture into the midwest.  The jet max is situated over the Great Lakes rounding the ridge that is continuing to make its way east.  As the night progresses, the flow will become more zonal.  A trough that is stationed over the NW portion of the CONUS deepens as we begin to see confluence from the polar and tropic upper level jets over Colorado. This 250-mb upper level jet develops 2 jet streaks indicating cyclonic development with the axis sitting over South Dakota. Moisture will slowly dissipate overnight, especially at the 700-mb level.  There is disagreement in the models, as the GFS has significantly more drying than the NAM through Missouri.  More moisture will be prevalent closer to the surface.  The decrease in cloud cover overnight will allow for temperatures to drop down into the mid 40s. 

For Friday, zonal flow at 250-mb will persist throughout the day.  There is a jet max situated to the north over Iowa and northern Illinois in the area where confluence is still prevalent.  A center of low pressure develops off the coast of California as a shortwave trough begins to take shape.  At 500 mb, bands of vorticity stay to the north of Missouri, sitting along the Iowa/Missouri border.  Conditions at 700-mb will stay dry for the majority of Friday with the moisture building back in overnight. Clouds build back in along with this moisture as well as our next round of showers coming from the low to Missouri's north. The rain will come in small amounts Saturday morning but the models are in disagreement about timing.  The NAM has the system reaching mid Missouri early Saturday around 9Z where as the GFS has the timing later at 12Z. Both models agree that we will see less than a tenth of rain for Saturday morning.

A shortwave riding the southwesterly flow will eject out of the Southern Plains into the Midwest Saturday morning. This already moistened profile will set up precipitation development by 15Z as this wave slowly traverses through the area Saturday. Model disagreement shows as NAM moistens the atmosphere sooner than GFS and unsaturated sooner Saturday afternoon. GFS will not saturate completely until after 18Z Saturday but will continue rainfall into the evening hours. Therefore rainfall accumulation from GFS is around 0.25 inches while NAM is more conservative with 0.1 inch of rainfall. Convection looks to be limited as instability values with CAPE stay minimal to none and BRN values coast below 10 for the day. Cloudy skies will dominate the area for the entirety of the day will temperatures struggling to reach 60F Saturday afternoon.

GFS depicts a classic low pressure development takes place over Arizona late Saturday evening with a clockwise circulating upper level polar jet coming into Missouri down from North Dakota. What really paints this low pressure picture is a high pressure system in the lower levels of the atmosphere that develop in the later hours of Sunday out front of the low pressure system in Oklahoma. This indicates baroclinic instability setting all of this development up. Winds in Missouri stay northwesterly at 925-mb with cold air advection sweeping its way through and setting up high pressure conditions. Both NAM and GFS show central Missouri receiving trace amounts of rain early afternoon on Sunday. This is due to the confluence driving low that also develops over the Great Lakes. Single cell convection is the driving factor for this particular system with Missouri being caught on the SW divergence section. With Missouri being caught right in the middle of the low pressure system to the NE and the high pressure to the SW, it'll be interesting to see how the models depict out this deformation zone as we get closer to Sunday. However looking at GFS model soundings, Columbia lacks shear, instability, and moisture for good rain development Sunday afternoon. The only saturated level sits at 800mb with a dew-point temp of 33.0 degrees F and a temp of 35.3 degrees F. Beyond that, there's only half an inch of precipitable water, giving possible conditions for light rain, but not likely.