Scott Dennstaedt, PhD Posted January 31, 2020 Report Share Posted January 31, 2020 (edited) Take a look at the 1-hr forecast sounding below...what precip type is expected to reach the surface? Edited January 31, 2020 by Scott Dennstaedt Quote Link to comment Share on other sites More sharing options...
skydvrboy Posted January 31, 2020 Report Share Posted January 31, 2020 Hmm... this is another tough one. The temp and dewpoint are equal and sitting right at 0 C almost down to the ground. I'm going to say they are getting a warm wet snow. I'm tempted to say that's mixed with freezing fog, but it looks like the temperature is too warm at the surface for the fog to freeze. Am I close? By the way, I love these and wish you would post more, even some simple ones to give us newbies a chance! 1 Quote Link to comment Share on other sites More sharing options...
Trailboss Posted January 31, 2020 Report Share Posted January 31, 2020 I could really use a class in reading these, but I'd say wintry mix of wet snow and cold rain. 1 Quote Link to comment Share on other sites More sharing options...
Scott Dennstaedt, PhD Posted January 31, 2020 Author Report Share Posted January 31, 2020 2 hours ago, skydvrboy said: Hmm... this is another tough one. The temp and dewpoint are equal and sitting right at 0 C almost down to the ground. I'm going to say they are getting a warm wet snow. I'm tempted to say that's mixed with freezing fog, but it looks like the temperature is too warm at the surface for the fog to freeze. Am I close? By the way, I love these and wish you would post more, even some simple ones to give us newbies a chance! Yes, it is a tough one...otherwise I wouldn't have asked the question. You are in the ballpark, but not necessarily completely correct. However, you are right, it wouldn't be freezing fog...first, freezing fog isn't a precipitation type, it's an obstruction to visibility (I specifically asked about precip type, e.g., rain, snow, ice pellets, freezing rain, etc). Second, the surface temperature is warmer than 0°C...freezing fog is reported if the visibility is less than 5/8ths of a mile and the ambient temperature is also below freezing. 1 Quote Link to comment Share on other sites More sharing options...
M20F Posted January 31, 2020 Report Share Posted January 31, 2020 Cloudy with a chance of meatballs. 1 Quote Link to comment Share on other sites More sharing options...
Scott Dennstaedt, PhD Posted January 31, 2020 Author Report Share Posted January 31, 2020 2 hours ago, Trailboss said: I could really use a class in reading these, but I'd say wintry mix of wet snow and cold rain. Yep, have held several webinars on reading the Skew-T and have recorded a few. Quote Link to comment Share on other sites More sharing options...
Scott Dennstaedt, PhD Posted January 31, 2020 Author Report Share Posted January 31, 2020 Just now, M20F said: Cloudy with a chance of meatballs. Yep. A few more degrees colder, frozen meatballs. Quote Link to comment Share on other sites More sharing options...
aviatoreb Posted January 31, 2020 Report Share Posted January 31, 2020 1 hour ago, Scott Dennstaedt said: Yep. A few more degrees colder, frozen meatballs. 1 Quote Link to comment Share on other sites More sharing options...
aviatoreb Posted January 31, 2020 Report Share Posted January 31, 2020 You know what's worse than meatballs, is frozen meatballs falling from the sky. Can you imagine the damage that would do to your stabilizer? Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted January 31, 2020 Report Share Posted January 31, 2020 Low ceilings light rain and mist. Quote Link to comment Share on other sites More sharing options...
mike_elliott Posted January 31, 2020 Report Share Posted January 31, 2020 Scott will be one of the Mooney Summit VIII Subject Matter Experts giving a great presentation on Saturday, Oct 17th! He will also be at Peter Oknight KTFP for airport day and perhaps host a round table on Friday Oct 16th. If you haven't registered yet, sign up HERE. This Mooney Summit should be the best one yet and is ever important in today's times. Thanks for doing this Scott, your expertise will be most valuable! 4 Quote Link to comment Share on other sites More sharing options...
Scott Dennstaedt, PhD Posted January 31, 2020 Author Report Share Posted January 31, 2020 7 minutes ago, mike_elliott said: Scott will be one of the Mooney Summit VIII Subject Matter Experts giving a great presentation on Saturday, Oct 17th! He will also be at Peter Oknight KTFP for airport day and perhaps host a round table on Friday Oct 16th. If you haven't registered yet, sign up HERE. This Mooney Summit should be the best one yet and is ever important in today's times. Thanks for doing this Scott, your expertise will be most valuable! Thanks Mike! Yep, the presentation I'm doing at the Mooney Summit is one that might save your life! Bring your weather questions. 1 Quote Link to comment Share on other sites More sharing options...
kortopates Posted January 31, 2020 Report Share Posted January 31, 2020 (edited) Looks like freezing level starts at 1000' with it above freezing at the surface and below 1000'. Ordinarily freezing precipt falling into warmer air on the surface would melt snow to rain. But if the surface layer above freeing is very narrow then we can have freezing precipt like snow fall to the above freezing surface as snow and then melt. I can't tell surface elevation but it does look like a potentially narrow enough above freezing surface air that this could be occurring. The other clue is that the air is only at 0C or barley minus all the way up to 6-7K level but the air is saturated to at least 15K - and those winds above 10K don't look like fun. I'll add its looks quite stable all the way up through 500mb Edited January 31, 2020 by kortopates Quote Link to comment Share on other sites More sharing options...
Yetti Posted January 31, 2020 Report Share Posted January 31, 2020 wet Quote Link to comment Share on other sites More sharing options...
mike_elliott Posted January 31, 2020 Report Share Posted January 31, 2020 Looks like freezing level starts at 1000' with it above freezing at the surface and below 1000'. Ordinarily freezing precipt falling into warmer air on the surface would be melt snow to rain. But if the surface layer above freeing is very narrow then we can have freezing precipt like snow fall to the above freezing surface as snow and then melt. I can't tell surface elevation but it does look like a potentially narrow enough above freezing surface air that this could be occurring. The other clue is that the air is only at 0C or barley minus all the way up to 6-7K level but the air is saturated to at least 15K - and those winds above 10K don't look like fun. Oh, I forgot to mention Paul Kortopates will be a Subject Matter Expert also at the Mooney Summit VIII. All those pesky "LOP/ROP" OWT's will be addressed with authority!Thanks Paul, your generous contribution of your expertise is much appreciated by the Mooney Community!Sent from my Pixel 2 XL using Tapatalk 4 Quote Link to comment Share on other sites More sharing options...
Denver98 Posted February 1, 2020 Report Share Posted February 1, 2020 I’m going with Freezing Rain. Cold air over taking warm air, typically causes a temp inversions. The cold air pushes the warm air up and the moisture freezes as it falls to the ground. Quote Link to comment Share on other sites More sharing options...
Scott Dennstaedt, PhD Posted February 2, 2020 Author Report Share Posted February 2, 2020 So here's the answer to the original question...given this forecast sounding, what precip type would you expect *at the surface*? I am not asking about what might be lurking 1000 feet or more above the surface. Second, this is a forecast sounding, not an observational sounding from a radiosonde. The answer is...there isn't a definitive answer except to say, it's definitely NOT freezing rain and it's very likely a mixed precipitation scenario. Freezing rain *at the surface* would require that the surface temperature be less than 0°C. In this forecast sounding, it is not. There is a deep isothermal layer (temperature remaining constant with height) from just above the surface to about 7000 feet MSL. This isothermal layer is hugging the 0°C isotherm. I know that this will have snow as a mixture since this is a deep system with cold cloud top temperatures (<< -20°C). The variable is, what will it be mixed with. The two choices are rain and/or ice pellets. The isothermal layer isn't warm enough to entirely melt the snow. However there will likely be some snow that does partially melt and may re-freeze into ice pellets or stay liquid as rain. All of this depends on just how much the actual temperature swings to the warmer or colder side of the 0°C isotherm. This was in Charlotte and I can say for sure that it started out as some wet snowflakes and then mixed with ice pellets and then switched to a mixture of snow and rain. Initially, the TAF for KCLT was showing light rain. KCLT 311409Z 3114/0118 03005KT P6SM BKN080 OVC200 FM311600 04005KT P6SM SCT040 BKN070 TEMPO 3116/3118 4SM -RA BR SCT025 BKN040 FM311800 01005KT 4SM -RA BR OVC023 FM312000 04006KT 3SM -RA BR OVC012 FM312200 02006KT 4SM -RA BR OVC007 FM011200 34004KT 3SM BR BKN015= Then they amended the TAF to include a mixture of snow and ice pellets. Likely after KCLT began reporting PL mixed with rain around 1535Z and later at 1552Z it was mixed snow and rain. KCLT 311559Z 3116/0118 03005KT 6SM -RA OVC060 TEMPO 3116/3117 2SM -SNPL BR BKN025 OVC040 FM311700 01005KT 4SM -RA BR OVC023 FM312000 04006KT 3SM -RA BR OVC012 FM312200 02006KT 4SM -RA BR OVC007 FM011200 34004KT 3SM BR BKN015= SPECI KCLT 311535Z 27004KT 8SM -PLRA OVC060 04/M02 A3028 RMK AO2 RAB08PLB34 PRESRR P0000 T00391017= SPECI KCLT 311543Z 28005KT 8SM -RA OVC055 04/M01 A3029 RMK AO2 RAB08PLB34E42 P0000 T00391011= METAR KCLT 311552Z 29005KT 9SM -SNRA BKN045 OVC055 03/M01 A3029 RMK AO2 RAB08PLB34E42SNB51 SLP259 P0000 T00331011= 2 2 Quote Link to comment Share on other sites More sharing options...
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