Jump to content
  • Member Statistics

    17,615
    Total Members
    7,904
    Most Online
    Vesuvius
    Newest Member
    Vesuvius
    Joined

March 11-12th Winter Storm Part 2


Chicago Storm

Recommended Posts

  • Replies 918
  • Created
  • Last Reply

Curious: Don't think I've ever seen anyone post a TAF before. So if I may ask: What is TAF & what does this all mean?

TAF stands for Terminal Aerodrome Forecast. It's a point forecast for the airports (within 5 mile radius of the runways) for the next 24 to 30 hours (ORD is a 30 hr TAF site). This forecast is for 6z (zulu or GMT) tonight until 12z Wednesday. Each FM (from) group is a forecast for a change in prevailing conditions at the indicated time. The first forecast group in each line is wind direction in degrees and speed in knots. The next group is visibility in statute miles, or SM. P6SM is unlimited visibility. If there is a restriction to visibility forecast, the weather causing it is listed next, or if there is no weather the next group lists the cloud coverage and height of the cloud bases. The TEMPO group is 50% or higher confidence in the forecasted conditions occurring at least occasionally (50% or more of the time) in a 1-4 hour time range. In the case of this TAF, it's indicating a start time to light snow at 4z- 11pm tomorrow evening with prevailing visibility 1.5 miles, followed by 3/4 mile visibility at 1am/06z. But then between 06z and 10z/1-5 am, the forecaster working the aviation desk indicated 50% or higher confidence in occasional moderate 1/2 mile visibility snowfall rates in snow and blowing snow (BLSN). Cloud ceilings are indicated to fall to 1500' (015) in the late evening to 900' (009) overnight, and VV006 in the TEMPO group means vertical visibility falling to only 600'. VV is used when there is no observable cloud base and it denotes the vertical visual range. 

Link to comment
Share on other sites

TAF stands for Terminal Aerodrome Forecast. It's a point forecast for the airports (within 5 mile radius of the runways) for the next 24 to 30 hours (ORD is a 30 hr TAF site). This forecast is for 6z (zulu or GMT) tonight until 12z Wednesday. Each FM (from) group is a forecast for a change in prevailing conditions at the indicated time. The first forecast group in each line is wind direction in degrees and speed in knots. The next group is visibility in statute miles, or SM. P6SM is unlimited visibility. If there is a restriction to visibility forecast, the weather causing it is listed next, or if there is no weather the next group lists the cloud coverage and height of the cloud bases. The TEMPO group is 50% or higher confidence in the forecasted conditions occurring at least occasionally (50% or more of the time) in a 1-4 hour time range. In the case of this TAF, it's indicating a start time to light snow at 4z- 11pm tomorrow evening with prevailing visibility 1.5 miles, followed by 3/4 mile visibility at 1am/06z. But then between 06z and 10z/1-5 am, the forecaster working the aviation desk indicated 50% or higher confidence in occasional moderate 1/2 mile visibility snowfall rates in snow and blowing snow (BLSN). Cloud ceilings are indicated to fall to 1500' (015) in the late evening to 900' (009) overnight, and VV006 in the TEMPO group means vertical visibility falling to only 600'. VV is used when there is no observable cloud base and it denotes the vertical visual range.

What a detailed, descriptive explanation. Thank you, sir. This'll actually come in handy as my mom's got a flight that's scheduled to leave ORD late Wednesday morning.

Link to comment
Share on other sites

This has rapidly become very exciting. March and April are Detroit's big dog months, so maybe, just maybe...

Look... you weenies south of here can have all the snow you want, just as long as this crap stays out of Genesee county. It's BANNED here. Nobody wants more snow here. If it happens, people up here will go off the rails for real.

Link to comment
Share on other sites

Euro is North of the 12z run, more moist too. Huge differences in Chicago from 00z, went from a DAB to around .4-.6" QPF for Chicago.

That's a substantial shift north for the Euro in this range. Have to think for the LOT CWA given the shifts north in all the guidance that the existing watch will be converted to a warning and warnings also hoisted for the Chicago area except maybe the far north and northwest (Wisconsin border counties). Even if amounts are forecast to be more high end advisory to lower end warning criteria-6" in 12 hours is the strict criteria- my guess is that weight will be given to the very strong winds developing, snow covered roads and snow still falling during the Weds am commute which will make for terrible travel conditions.

Link to comment
Share on other sites

Euro better here, but still shows big blob of heavy precip very close to the surface low tomorrow evening, with much less up in the cold sector.  Still think it's under playing things further north tomorrow evening.

 

Yeah I definitely agree, something still looks funky with that.

Link to comment
Share on other sites

BuffaloWx, your images aren't coming through for me (not sure if anyone else is seeing them).

  same...Nada

Look... you weenies south of here can have all the snow you want, just as long as this crap stays out of Genesee county. It's BANNED here. Nobody wants more snow here. If it happens, people up here will go off the rails for real.

Everyone I talked to today felt the same way down here. It is becoming a bit much but I want that age-old record shattered. Today felt amazing though outside of the grass turning to quick sand and standing muddy water everywhere from rapid snowmelt.
Link to comment
Share on other sites

Wednesday Snow before 4pm. High near 26. Windy, with a north wind 16 to 25 mph, with gusts as high as 39 mph. Chance of precipitation is 100%. New snow accumulation of 3 to 5 inches possible

 

 

If even just that panned out those winds would be ridiculous, if we get closer to 8 or more inches that's borderline b-word stuff.

Link to comment
Share on other sites

What a detailed, descriptive explanation. Thank you, sir. This'll actually come in handy as my mom's got a flight that's scheduled to leave ORD late Wednesday morning.

You're welcome- glad to help out. There's a few things I left out still but the more TAFs you look at, the easier they are to understand, and they are really helpful in being able to expect delays because anything below 3 mile visibility and 1,000 ft ceilings is considered IFR (instrumental flight rules) and usually causes problems before the acceptance rate for arrivals goes down. When winds are north or northeast or east, any ceilings below 3,000 feet actually cause problems now at ORD with the new runway configuration. 

Link to comment
Share on other sites


this is gonna be fun...

TIPPECANOE-  

INCLUDING THE CITIES OF...LAFAYETTE  

359 AM EDT TUE MAR 11 2014  

 

...WINTER WEATHER ADVISORY IN EFFECT FROM 4 AM TO 4 PM EDT  

WEDNESDAY...  

   

TODAY  

PARTLY CLOUDY UNTIL MIDDAY THEN BECOMING MOSTLY CLOUDY.  

HIGHS IN THE LOWER 60S. SOUTH WINDS UP TO 10 MPH SHIFTING TO THE  

WEST IN THE AFTERNOON.    

TONIGHT...VERY WINDY. RAIN AND SLIGHT CHANCE OF THUNDERSTORMS  

 

THEN RAIN...POSSIBLY MIXED WITH SNOW AND SLEET AFTER MIDNIGHT.  

AREAS OF BLOWING SNOW AFTER MIDNIGHT. SNOW AND SLEET ACCUMULATION  

UP TO 2 INCHES. LOWS IN THE UPPER 20S. NORTHEAST WINDS 10 TO  

15 MPH WITH GUSTS TO AROUND 25 MPH INCREASING TO NORTH 15 TO  

30 MPH WITH GUSTS TO AROUND 40 MPH AFTER MIDNIGHT. CHANCE OF  

PRECIPITATION NEAR 100 PERCENT.    

WEDNESDAY  

VERY WINDY. MUCH COLDER. MOSTLY CLOUDY. AREAS OF  

BLOWING SNOW UNTIL MIDDAY. SNOW UNTIL MIDDAY...THEN CHANCE OF  

SNOW IN THE AFTERNOON. SNOW ACCUMULATION OF 2 TO 3 INCHES. TOTAL  

SNOW ACCUMULATION 2 TO 5 INCHES. HIGHS IN THE UPPER 20S.  

TEMPERATURE STEADY OR SLOWLY FALLING IN THE AFTERNOON. NORTH  

WINDS 20 TO 30 MPH WITH GUSTS TO AROUND 40 MPH. CHANCE OF SNOW  

80 PERCENT. WIND CHILL READINGS 3 BELOW TO 7 ABOVE ZERO.    

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...