Friday, February 28, 2020

    




Friday Night - Cloudy becoming clear. Low: 28-32



Saturday - Sunny. High: 54-58



Saturday Night-  Few Clouds.  Low: 42-46

Sunday - Becoming cloudy. Possible late evening rain. High: 62-66



 Monday - Scattered Clouds. Possibility of rain. High: 46-52



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Discussion: 
We warm up this weekend as a low pressure system moves away from us and we become under the influence of a ridge. However, this is short lived as we expect precipitation from Sunday night into Monday as another low pressure system comes into from the west of us.   
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Forecasters: Balkissoon, Munley
Issued:  5:00pm: February 28, 2020

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

The WPC Model Diagnostics indicate that a general model blend is preferred with an above average confidence.  As such, this briefing we will look at the GFS model in the top down approach and will focus in on the SREF for the accumulative precipitation amounts and temperature trends.

From the 250-hPa map of winds, heights, wind divergence and wind speeds.  Today we note that there do not exist any significant upper level divergence over Missouri.  We also observe that we sit on a base of a positively tilted trough.  This is indicative that the low has not fully developed or matured.  However, from Saturday to Sunday we become under the influence of a ridge which can account for the warm up this weekend.  There is no significant upper level divergence over us until Monday at 9Z.  This divergence aloft can be associated with the low pressure system which, from the model, is located at the SW of us at this time. 

From the 500-hPa map of Heights and Vorticity, we observe regions of circulation over Missouri on Saturday at 0Z.  This positive vorticity noted is associated with the low pressure to the east of us.  As this system moves, we do not see significant disturbance in the atmosphere until Sunday at 18Z.   It is around this time, 21Z, after consulting the SREF we observe that rainfall is expected. 

From the 700-hPa Height and Omega map, even though we observe moisture Friday night over our domain, we do not see the required lift to support precipitation.  This is not the case on Sunday night into Monday where we see moisture but some lift.  This is also supported by the GFS skew-T in which there is non-zero CAPE value indicative that there is some upward vertical velocity. 

From the 1000-500 hPa thickness and pressure map, we note that we are under the 540 line which indicates that we are above freezing.  This line moves to the north of us as we toggle through the weekend.  This is also indicative of our warm up.  Also, WAA is noted observing the solenoids, as the pressure is seen to increase to the west of us.  From the skew-T, we do note our winds backing with height which indicates again, WAA. 

Thursday, February 27, 2020

    
Thursday Night - Mostly Cloudy. Low: 26-30
 


Friday - Mostly Cloudy. High: 42-46



Friday Night - Cloudy becoming clear. Low: 28-32
 


Saturday - Mostly Sunny. High: 54-58



Sunday - Becoming cloudy. Possible late evening rain. High: 62-66


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Discussion: 
Northwesterly winds and moderate cloud cover make tonight and tomorrow similar to last night and today in terms of temperature. However, these winds will transition to southwesterly and cloud cover will clear out Friday into Saturday, causing significant warming that will continue into midday Sunday. At that point, clouds will return as low pressure from the west brings moisture and the possibility for precipitation in the evening.
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Forecasters: Lieberman, Ritter
Issued:  5:00pm: February 27, 2020

Technical Discussion (The nerdy stuff we are discussing in class)
A general blend of the GFS and NAM was supplemented with SREF plumes. The WPC recommends a general blend. At 250MB, a jet max is located northeast of New England and meridional flow dominates the CONUS with a longwave trough centered from Ontario to the Gulf of Mexico. At 500MB, meridional flow is reflected downward and a significant low pressure system is centered over the Great Lakes and southern Ontario. At 700MB, it is clear that the low is not stacked as the center is located over eastern Ontario, further east than at 500MB. This trend continues down to 850MB where the low is centered slightly further east over the border of Ontario and Quebec. At the surface, the effects of the low are negligible for central Missouri and a stationary front is located on the Missouri Iowa border.



Going forward, both the GFS and NAM show zonal flow setting in from west to east at 250MB as the cyclone matures and fills in and the longwave trough moves east and out of the CONUS. A jet max oriented west-east moves east along the southeast US putting Missouri in the left exit region. This is reflected at 500MB where flow will transition from a more northerly component on the backside of the low in Missouri to westerly as zonal flow sets in. Additionally, a ribbon of higher rotational energy associated with the backside of the cyclone will pass over Columbia Friday evening. Soundings indicate UVM; additionally, the GFS and SREF plumes indicate trace precipitation is possible. However, both the NAM and GFS show insufficient moisture in soundings and inspire very little confidence for precipitation.


Both soundings and 850MB RH charts show moisture clearing out Friday night into Saturday morning. Additionally, as zonal flow sets in aloft, significant veering is observed along with tight pressure contours running perpendicular to thickness contours creating multiple solenoids over the greater Missouri area. Therefore, significant WAA is expected along with radiational heating throughout Saturday and persisting until late Sunday. This will result in unseasonably warm and increasing temperatures through the forecast period.


Midday Sunday, a small disturbance shows moderate rotational energy entering Missouri. This is complemented with moderate UVM according to both NAM and GFS soundings. However, moisture will likely be insufficient for precipitation until late Sunday. Future forecasters should monitor the energy of this disturbance and moisture advection.

Wednesday, February 26, 2020

 
Wednesday Night - Mostly Clear. Low: 22-26 
 
 
Thursday- Increasing Clouds. Sprinkles possible in the afternoon. High: 42-46  




Thursday Night - Mostly Cloudy. Low: 26-30


 
Friday - Mostly Cloudy. High: 42-46
 

 
Saturday - Mostly Sunny. High: 56-60





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Discussion: 
For tonight, expect clouds to clear. This will allow lows to drop into the mid-20s. On Thursday, winds will become southwesterly, helping mid-Missouri to warm up more than today. Maximum temperatures will likely reach the low to mid-40s. Clouds will be on the increase during the afternoon hours due to a passing disturbance, which could also squeeze out a few sprinkles. For Friday, expect temperatures to stay in the 40s, with westerly winds and mostly cloudy skies keeping us from getting much warmer. That warm-up will have to wait until Saturday, which -- with southwest winds and brilliant sunshine -- should reach the upper-50s.
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Forecasters: Pauley, Vanderpool, Ritter
Issued:  5:00pm: February 26, 2020

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

The 18z NAM and 12z GFS showed remarkable agreement (through analysis of 500mb heights and winds) throughout the forecast period. With the WPC recommending a general model blend (and with the NAM progging Wednesday afternoon temperatures about 10 degrees warmer than observed values) we went with the 12z GFS throughout the period, as it had a better handle on surface temperatures.

21z WPC analysis indicated a surface low centered over West Virginia. This low was tilted west with height, as confirmed by 21z RAP analysis. The 500mb trough was just barely beginning to see a negative tilt, with its axis extending from northeastern Minnesota through central Illinois. Short-term prognostics from the RAP and GFS indicates that this trough will take on a steep negative tilt over the next 18 hours, which will serve to deepen the surface cyclone over the eastern CONUS.

For mid-Missouri, wrap-around moisture between 850 mb and 700 mb was responsible for cloudy skies, with relatively steep (7 - 7.5 C/km) low-level lapse rates helping to generate cumulus clouds and even a few snow showers. Lapse rates will become less steep throughout the evening, which -- along with drying in the aforementioned 850-700 mb layer -- will lead to clearing skies.

Tonight, clearing skies and light winds will help us to fall into the low to mid 20s. We decided to raise overnight lows a few degrees from the previous shift based upon SREF and HREF model spreads, which both forecast temperatures in the 22 - 27 degree range. Given that there is no snow on the ground, we believe that a range of 22-26 degrees is reasonable.

Thursday, surface winds will switch to the southwest. GFS soundings for 15z Thursday indicate veering in the low and mid levels of the atmosphere. That veering will create warm air advection, boosting surface temperatures into the mid-40s. Tomorrow afternoon, a small shortwave will push into the area. This disturbance will saturate the atmosphere between 850 and 300 mb, leading to increasing cloud cover. There is also the potential for sprinkles or light passing showers, as the saturation aloft is accompanied by decent vertical motion. However, any rain will have to fall through some pretty dry air near the surface, which will limit our overall chances for it.

Friday, another shortwave disturbance will pass over the area. However, it doesn't have much moisture to work with at the surface, so right now it looks like clouds will be the main impact. Future shifts will need to watch this, however, because any increase in moisture and lift could lead to more stray showers or sprinkles.

Saturday, a warmup begins in earnest as strong warm air advection combines with mostly sunny skies beneath a developing ridge. It currently looks like temperatures should hit the mid- to upper-50s, with warmer temperatures certainly not out of the realm of possibility. 









Tuesday, February 25, 2020





 

Tuesday Night - Rain/Snow Showers. Low: 26-30



Wednesday - AM Snow/Afternoon Clearing. High: 32-36


 
Wednesday Night - Clear Skies. Low: 18-22

              
                 
 Thursday - Partly Cloudy. High: 38-42



 
Friday - Partly Cloudy. High: 38-42












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Discussion: 
Rain and snow showers will continue into tonight, and changeover to all snow is anticipated overnight with the rate of snowfall being light in nature. The snow will continue into tomorrow morning. By tomorrow afternoon, the skies will start to clear out and the skies will remain clear overnight into Thursday morning with cold temperatures overnight as well as high pressure takes over. Thursday there will be some increasing clouds, but not totally overcast and temperatures will be slightly below average. Overnight Thursday looks to remain partly to mostly cloudy with below average temperatures as well.
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Forecasters: Gallahan, Munley
Issued:  5:00pm: February 25, 2020

Technical Discussion (The nerdy stuff we are discussing in class)
 
Model guidance suggests a NAM/ECMWF/UKMET model blend. The NAM was used for this forecast period, and SREF plumes were used for temperatures. 

The main concern for this forecast period is the potential for rain and snow, and when the rain will transition to all snow, the intensity, and how much snow will fall.

Current set up at 250mb has the polar jet to the south of Columbia putting us in the base of the trough. This trough is positively tilted indicating that the system is hasn't matured yet. The system is also not vertically stacked with the 20z low's 250 mb located over western Kansas, and the surface low over southern Ohio. Even though the system isn't fully mature, the potential of a rain/snow mix looks to occur throughout the evening with a changeover to all snow starting around around 10 to 11pm tonight. The snow intensity doesn't appear to be much more than some light snow showers. This is because even though there is areas of circulation at 500mb over central Missouri and 700 mb RH values at 90%. The layer of cold air isn't very deep and there is a lack of UVM during this time. This potential for light snow will last until early tomorrow morning. During tomorrow afternoon, Columbia will be situated on the backside of the surface low which will cause the winds to shift to out of the north bringing in cold, and dry Canadian air for tomorrow night into Thursday morning. Thursday, and Thursday night, there will be an increase in clouds, however not totally overcast allowing the sun to pop out during the afternoon. This will warm the afternoon temperatures up somewhat, but  temperatures will still remain below season values. Friday looks to be a repeat of Thursday.

Monday, February 24, 2020






Monday Night - Overcast with rain early evening showers. Low: 34-38




Tuesday - Overcast with morning rain showers and evening snow showers High: 38-42




Tuesday Night - Overcast. Light snow showers. Low: 26-30




Wednesday - Early morning snow. Decreasing clouds throughout the day.  High: 32-36




Thursday- Clear. High: 36-40




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Discussion: 
Rain has been falling throughout the day, most recent amounts recorded at 0.83 inches. Rain totals through tonight are expected to reach close to an inch. The rain will dwiddle over night and pick back up again Tuesday morning. Snowfall is expected to begin Tuesday around sunset as temperatures begin to drop but there is little accumulation to be expected. Light Snowfall, if any, will be around until Wednesday morning when clouds are expected to clear bringing in sunshine all the way into Thursday. 
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Forecasters: Owens, Savoy, Ritter
Issued:  10:00am: February 24, 2020

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

Model verification is tricky today given that we are dealing with an occlusion moving through central Missouri. The SREF does not have the system occluded as deeply as the upper air data is showing. HREF does have a better handle on the situation. RAP and GFS Skew-t's were verified with upstream data, from KTOP and were within acceptable deviations, only being slightly warmer than KTOP, both being 3 degrees higher than the 12Z observed.

For the short term forecast, the rain will continue to fall until the occlusion and associated wrap-around moisture moves downstream of Columbia. Model products are currently progging this at 0500Z, and, using the extrapolation method on the radar, the center of the low is expected to follow this pattern.

While Central Missouri is dealing with the rain, the next weather system has been developing over North and South Dakota. As this system begins to move toward the Columbia area, snowfall and rain have to be considered. Current model timing is placing this system moving into the region Tuesday afternoon. With Columbia being well to the North of the 0-degree isotherm, at the 850-mb level than snow is a distinct probability. However, SFC temps are expected to be right around freezing, in the afternoon, so any snowfall should not accumulate. These will pass through early Wednesday morning.

After Cthulhu gets done spreading his insanity in the area, conditions are expected to improve. There will still be some cloud cover over Wednesday morning, however, this will dissipate and clear blue and 22 will dominate the area for the remainder of the period. With this, temps will be increasing on both Wednesday and Thursday, with temps going above freezing Wednesday afternoon.





Monday - Overcast. Rain showers likely all day. High: 44-48
 


Monday Night - Overcast. Isolated showers possible early evening, then dry until morning. Low: 34-38  


Tuesday - Overcast. Scattered showers through the day. High: 38-42
 

Tuesday Night - Overcast. Rain turning to snow early evening. Low: 26-30
 

Wednesday - Overcast morning; decreasing clouds through the day. Lingering snow showers possible in morning. High: 30-34




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Discussion: 
Rain is settled over Missouri today. As of 8am, Mizzou's campus has already received a little over 0.5" of rain, and at least another 0.5" is expected from this rain event. We expect some dry time overnight before rain ramps back up tomorrow. However, tomorrow's rain looks to be more scattered than today's widespread rain. Tuesday night, cold air moves into the state. Temperatures will drop and snow showers are possible on the backside of this system. Moisture will move out by midday Wednesday where we may finally see the sun again.
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Forecasters: Clemons, Farr, Heaven
Issued:  10:00am: February 24, 2020

Technical Discussion (The nerdy stuff we are discussing in class) 
Model guidance from the WPC recommends to use a general model blend given the average and less than average confidence of the next couple of days. Therefore, for this forecast we used a combination of the GFS, GEFS, and the SREF. The main focus for today's forecast will be the duration of the current precipitation, when the next wave of precipitation will start, and the precip type for Wednesday morning. 

Currently, the cyclone affecting our current weather is parked over northeastern Oklahoma. The present low is evident from 700mb down to the surface at this same location. This vertically stacked low helps diagnose this as a dying system. Around 21Z today at 700mb, the low parks itself over Missouri and remains stationary for a couple of hours. A developing cyclone looks to move south from South Dakota and begins to engulf the present low. This new system will likely strengthen due the vast amount of upper lever support such as a negatively tilted trough at 300mb. This system will then move northeast over the Great Lakes and continue to gain strength.

In terms of precipitation, today we will likely see rain all day. Soundings from the GFS show omega values dwindling around 03Z tomorrow indicating a possible break in precip tonight. Nevertheless, we remain saturated so isolated showers are still possible overnight. Tuesday remains relatively persistent in relation to today as the low still hovers over the Midwest. Omega values increase throughout the day so rain is forecasted to dominate our weather tomorrow. Rain totals look to be in the 1-1.5" range after all is said and done on Tuesday. Mizzou's campus has already received over 0.5" of rainfall, so we have high confidence in that forecasted amount.

Tuesday night into Wednesday, the aforementioned new system begins to translate to the northeast and matures rapidly. This results in CAA over Columbia, also enhanced by a LLJ from the north. Temperatures decrease quite a bit and we could see some snow from wraparound precip. However, the LLJ brings continental air which does not support moisture. This could potentially inhibit snowfall for Tuesday night. At this point in time, light snow showers are still possible, but future forecasters should keep an eye on the moisture and lift associated with this system.

Friday, February 21, 2020





Friday Night - Clear.  Low: 22-26

Saturday -  Sunny. High: 50-54



Saturday Night -  Clear.  Low: 32-36



Sunday - Cloudy with chances of rain.  High: 46-50



Monday - Cloudy with chances of rain.  High: 44-48



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Discussion: 
We warm up a bit for the beginning of the weekend, on Saturday, as we have no significant weather phenomenons taking place.  However, on Sunday due to the low pressure system moving in from the west, we are expecting some rainfall into Monday.
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Forecasters: Balkissoon, Heaven, Travis, Munley
Issued:  5:00pm: February 21, 2020

Technical Discussion (The nerdy stuff we are discussing in class) 
From the WPC model diagnostics, the GFS blend was recommended for forecast analyses however the confidence given was below average. As such our map discussion will be done using products from the GFS run.  For our temperature values and the total precipitation amounts, the GEFS plumes were consulted.

Our first map that we looked at is the 250-hPa wind, heights and divergence.  For this weekend we sit underneath the jet.  We observe divergence aloft which implies that there is convergence taking place near the surface.  This convergence at the surface that rises is indicative of cyclonic motion in which there is the expectation of precipitation around Monday at 6Z. 

From the 500-hPa absolute vorticity map, at Monday at 0Z, we have a low pressure system coming in from the west of Missouri.  We observe with this feature, an counter-clockwise curvature of wind flow.  This system is more mature as it has a closed off cycle. 

From the 700-hPa Omega and RH, we observe that there is significant amount of moisture which is being fed from the Pacific.  We do have the combination of lift and saturation which is the reason behind our expectation of precipitation Sunday evening into Monday.  This is also supported from the GFS skew-T which shows both moisture and omega starting from Sunday at 21Z.  From our analysis of the 850-hPa winds, heights and temperatures, we can infer that the precipitation type is rainfall as we are expected to be consistently above freezing into the weekend and early week.  This is so as the warmer air is coming from the South-West.  We also observe the warming effects from looking at the thickness 1000-500-hPa map where the thickness contours are moving closer together.  From this map we observe CAA taking place as the counter-clockwise rotation of the cyclone is bringing in cold air from the north. 

The GEFS plumes have a total accumulation of rainfall in the amount of a little under one and a quarter inches. 


Thursday, February 20, 2020


 
Thursday Night - Clear. Low: 18-22  
 


Friday - Sunny. High: 38-42 



Friday Night - Clear. Low: 22-26
 


Saturday -  Sunny. High: 50-54
 
Sunday - Becoming cloudy. Evening rain. High: 46-50



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Discussion: 
As high pressure sets in, there will northerly winds until Friday night bringing in cool, dry air. After the system passes over the central US, we will be left with southeasterly winds meaning warm, but still dry air. This will persist until a low pressure system nears Missouri on Sunday bringing moisture and a decent chance for rain.
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Forecasters: Dowell, Lieberman, Ritter
Issued:  5:00pm: February 20, 2020

Technical Discussion (The nerdy stuff we are discussing in class) 
We primarily used a general model blend of the GFS and NAM as well as SREF plumes and GEFS products. The WPC recommends a general model blend. Currently at 250MB, the jet max is located east of New England, placing Missouri in the left entrance region, increasing the chance for convergence aloft. Flow is primarily zonal over the CONUS. At 500MB, a longwave trough extends from Lake Eerie to Kansas. This feature has rotational energy associated with it over Mid-Missouri. At 700MB, moisture has just moved southeast of Missouri and the area is left with unsaturated air. At 850MB, an anticyclone centered over the Kansas-Nebraska border is causing northerly winds and CAA. At the surface this feature is reflected and station plots show northerly winds and temperatures in the high 20s (Fahrenheit) in the area.


The anticyclone will flow southeast Thursday night until midday along the Missouri-Arkansas border, allowing the CAA to continue. Along with clear skies and radiational heating, Friday will be significantly warmer than Thursday. With relatively no moisture in the area, cloud cover will be minimal or non-existent. Winds will be minimal as the center of the anti-cyclone passes just south of Columbia. Midday, CAA will begin to transition to WAA as the anti-cyclone travels downstream, bringing southwesterly winds and creating solenoids. This will continue overnight Friday into Saturday bringing WAA that will persist as Columbia will see unseasonably warm temperatures.





Saturday night, clear skies and radiational cooling are expected. However, temperatures will quickly warm again as flow remains
southerly and temperature gradients suggest increasing WAA throughout the day. Additionally, a low pressure system will approach from due west and bring moisture into Missouri. This system is expected to bring rotational energy and lift sufficient for stratiform rain beginning Sunday evening. SREF plumes are clustered into a warmer and cooler group for Sunday. dPROG/dt analysis suggest a cooling trend in more recent SREF runs. Therefore, it is expected that the temperatures will be in the mid to high 40's. QPF SREF plumes do not inspire confidence as the spread ranges from 0.02 inch to 1.04 inches with relatively no clustering. Moreover, dPROG/dt suggests an increasing trend. We expect around 0.5 inch of rain. Future forecasters should monitor the system and its expected precipitation output.