ATLwxfan
Member
CAD signal a bit weaker for next weekend on GFS. I ain’t mad.
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Pattern Fail or Fab February 2023 Pattern Thread
- Thread starter metwannabe
- Start date
HRRR warm tomorrow and Thursday afternon
Thursday
Thursday
Tarheelwx
Member
NWS now has GSO tomorrow topping out at 79 and RDU at 82. No surprise there.
TW
Yeah, the 6z 3k NAM has midafternoon temps only in the low 70s for RDU. The GFS and European are in the mid 70s. Canadian (as stated above) has mid 80s for RDU.
Nam is always way to cold, it was off by 7 degrees yesterday for example, it’s a known cold bias
a lot of high temp forecasting is simply figuring out how deep boundary layer mixing gets during the day, since mixing will bring those air parcels at 850mb or wherever down adiabatically.
NAM 3km- puts boundary layer at 925mb Thursday afternoon for Richmond. Temp? 75.
Different model- some WRF model- Boundary layer is around 890mb at same time. Temp? 77.
Nam in my experience underestimates the height of where the boundary layer gets to, whereas the GFS is better or can overestimate sometimes. That's where this nam bias comes from.
But generally that's where a lot of discrepancies will come from, and it's all about just how the model renders turbulence and microphysics and those things are pretty hard to get right. I bet a lot of the NWS forecasts are betting that with how windy it is most models will underestimate the amount of mixing (and don't forget to add some downsloping in their for good measure)
That and cloud cover, but I think ya'll know this, if there's more clouds than forecasted Thursday (totally possible) then the highs will not be all time monthly records. lol.
Chazwin
Member
GSP doesn’t seem to be too excited about the idea of setting monthly records tomorrow. They note that the guidance that is pushing highs up over February records also start the day with clear skies… they expect that there will be cloud cover that will take most of the morning to burn off.a lot of high temp forecasting is simply figuring out how deep boundary layer mixing gets during the day, since mixing will bring those air parcels at 850mb or wherever down adiabatically.
NAM 3km- puts boundary layer at 925mb Thursday afternoon for Richmond. Temp? 75.
Different model- some WRF model- Boundary layer is around 890mb at same time. Temp? 77.
Nam in my experience underestimates the height of where the boundary layer gets to, whereas the GFS is better or can overestimate sometimes. That's where this nam bias comes from.
But generally that's where a lot of discrepancies will come from, and it's all about just how the model renders turbulence and microphysics and those things are pretty hard to get right. I bet a lot of the NWS forecasts are betting that with how windy it is most models will underestimate the amount of mixing (and don't forget to add some downsloping in their for good measure)
That and cloud cover, but I think ya'll know this, if there's more clouds than forecasted Thursday (totally possible) then the highs will not be all time monthly records. lol.
Already 65F
I bet we're warmer today here than tomorrow.
I've been wondering about this. 850s are much more supportive of 80-85 today than tomorrow
There's a small difference between the NAM and RDPS.
12z RDPS (midafternoon tomorrow):
12z NAM (midafternoon tomorrow):
12z RDPS (midafternoon tomorrow):
12z NAM (midafternoon tomorrow):
when it's cooler from georgia to VA like this - it's really all about differences in how the model is resolving how deep the boundary layer gets. guarantee you the rdps is a solid 100mb deeper than nam.
Fountainguy97
Member
If you listen closely today and tomorrow you can hear the roar of the waterfalls from the melting snow at the ski resorts. Tough sledding for them this year.
cyclogent
Member
Currently 82 in Chattanooga. Warmest ever in February.
SWVAwxfan
Member
That's crazy as KCAE was also 82.
Looking forward to next winter when we can get into the 90s.
SWVAwxfan
Member
Why wait till next year? You could head on down to Immokalee FL and get it now.
