GaWx

NWS 11/15/2013 probabilities for DJF 2013-4 weren’t all that telling as they underdid the prospects for widespread cold though they hinted ok at where the coldest and warmest ended up being:

NWS DJF 2014-15 probabilities released in 11/2014: best cold chances centered in south Actual 2014-5 DJF vs 1981-2010: coldest in NE not south, which was only slightly BN

Does anyone know if archived Cansips seasonal forecasts are available somewhere so we can easily see how they’ve done overall?

If someone had the time, they could go through AmericanWx threads for each winter and find CANSIPS forecast maps (however far back they go) and compare to what verified. Any volunteers?

Hey Mitch, I’m confident that you realize that a model bias in whatever direction doesn’t mean it’s almost never going to miss in the opposite direction. A typical model bias could be something like verifying consistent with the bias 65% of the time while verifying the opposing way 20% of the time and being close 15% of the time. For example, the April 30th CANSIPS forecast for May was actually too warm, especially in Midwest/OH Valley/NE (though a bit too cool E VA S to FL): 4/30/25 CANSIPS for May ‘25 (in C vs 1981-2010): Actual May ‘25 (in F) vs 1981-2010: But the 2/28/25 CANSIPS verified as being significantly too cold for Mar ‘25 vs the reality of a very warm month. It was mainly warmer than normal but not nearly warm enough in most of the E US. Whereas CANSIPS was much too warm in Jan and too warm in Feb, it was much too cold in Dec.

Chris, Very well said about model biases! I couldn’t agree with you more. When significant clearcut cold biases are identified, it isn’t cherry picking to point out a much too cold model verification. If a model is too cold and has too low H5 hts in the E 1/2 of the US, say, 75-80% of the time, it isn’t cherry picking. The same could be said for any identified clear cut biases for any model.

Thanks, Charlie! Yes, I recall you mentioning the surface winds being higher this year vs last thus resulting in cooling from upwelling. Regardless, I think it’s important to always expose JB when he spreads misinfo about underwater seismic being the main factor in ocean warming and now cooling. I don’t expose it and other stuff like this because I necessarily agree with it. However, sometimes I like being reminded of the true explanation. Also, I expose it to show how often it’s being spouted as well as to generate responses like yours to keep others informed who are just reading this stuff from JB for the first time of how far off JB is. Thus, I expect to repost more of this JB nonsense as he continually posts it in the near future.

BULLETIN Tropical Storm Chantal Intermediate Advisory Number 6A NWS National Hurricane Center Miami FL AL032025 200 AM EDT Sun Jul 06 2025 ...CHANTAL A LITTLE STRONGER AND CLOSE TO LANDFALL ALONG THE SOUTH CAROLINA COAST... ...FLASH FLOODING CONCERNS INCREASE AS RAINBANDS MOVES ONSHORE... SUMMARY OF 200 AM EDT...0600 UTC...INFORMATION ---------------------------------------------- LOCATION...33.2N 78.8W ABOUT 75 MI...115 KM ENE OF CHARLESTON SOUTH CAROLINA ABOUT 85 MI...140 KM SW OF WILMINGTON NORTH CAROLINA MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H PRESENT MOVEMENT...N OR 350 DEGREES AT 8 MPH...13 KM/H MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES Recent aircraft and land-based radar velocity data indicate that maximum sustained winds have increased to near 60 mph (95 km/h) with higher gusts. Little change in strength is expected before landfall, with rapid weakening forecast after landfall. Tropical-storm-force winds extend outward up to 140 miles (220 km) from the center. Within the past hour, Springmaid Pier in South Carolina reported a sustained wind of 47 mph (76 km/h) gusting to 56 mph (90 km/h). The estimated minimum central pressure based on Air Force dropsonde data is 1002 mb (29.59 inches).

Posted just after 1AM in SE subforum by someone visiting N Myrtle Beach, he said this at ~1AM as it’s gotten quite stormy there (consistent with the radar): “Hello everyone, I normally post on the New England forum however I am in North Myrtle Beach and the weather has quickly deteriorated to heavy squalls and the wind has increased considerably in the last 30 minutes from an estimated 10 to 15 miles an hour to 20 to 25 with a couple of gusts that have been 40mph at least, I don’t have an anemometer however I think that is a pretty close estimate.”

As Barry posted, flash flooding is the biggest concern from Chantal. This covers NE SC and SE NC. The main area of solid rain is just entering these areas:URGENT - IMMEDIATE BROADCAST REQUESTED FLOOD WATCH NATIONAL WEATHER SERVICE WILMINGTON NC 1250 PM EDT SAT JUL 5 2025 NCZ099-109-110-SCZ054-058-059-061215- /O.NEW.KILM.FA.A.0002.250705T1700Z-250708T0000Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ COLUMBUS-INLAND BRUNSWICK-COASTAL BRUNSWICK-COASTAL HORRY-CENTRAL HORRY-NORTHERN HORRY- INCLUDING THE CITIES OF MYRTLE BEACH, LONG BEACH, SHALLOTTE, OAK ISLAND, AYNOR, LONGS, SOUTHPORT, LORIS, BUCKSPORT, CHADBOURN, BOILING SPRING LAKES, GARDEN CITY, SOCASTEE, SUNSET BEACH, GREEN SEA, NORTH MYRTLE BEACH, LELAND, WHITEVILLE, LITTLE RIVER, TABOR CITY, LAKE WACCAMAW, AND CONWAY 1250 PM EDT SAT JUL 5 2025 ..FLOOD WATCH IN EFFECT THROUGH MONDAY EVENING * WHAT...FLASH FLOODING CAUSED BY EXCESSIVE RAINFALL IS POSSIBLE. * WHERE...PORTIONS OF SOUTHEAST NORTH CAROLINA, INCLUDING THE FOLLOWING AREAS, COASTAL BRUNSWICK, COLUMBUS AND INLAND BRUNSWICK AND NORTHEAST SOUTH CAROLINA, INCLUDING THE FOLLOWING AREAS, CENTRAL HORRY, COASTAL HORRY AND NORTHERN HORRY. * WHEN...THROUGH MONDAY EVENING. * IMPACTS...EXCESSIVE RUNOFF MAY RESULT IN FLOODING OF RIVERS, CREEKS, STREAMS, AND OTHER LOW-LYING AND FLOOD-PRONE LOCATIONS. * ADDITIONAL DETAILS... - HEAVY RAIN FROM TROPICAL STORM CHANTAL WILL INCREASINGLY EFFECT THE AREA LATE TONIGHT INTO SUNDAY. - WEATHER.GOV/SAFETY/FLOOD PRECAUTIONARY/PREPAREDNESS ACTIONS... BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE DANGERS OF FLOODING. YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION SHOULD FLASH FLOOD WARNINGS BE ISSUED.

Today the new monthly Euro seasonal outlook was released for August and beyond in the ATL basin. Compared to the prior monthly forecast, which was near the avg for the active period 1993-2015 for # of TS+/# of H and very slightly above the avg ACE, the new one is very slightly less active with very slightly below the 1993-2015 avg for # of TS+/# of H and right at the active period’s ACE avg. It’s forecasting 6.0 hurricanes vs a 6.7 avg. Last year at this time, it forecasted 8.4 of them for the same period in 2024. 2024 actually had 11 for July+. So, though beside my point, it wouldn’t surprise me if the 6 is a good bit too low especially if we end up with weak La Nina per RONI I predicted 9 H for 2025. The distribution of storms is similar to the prior forecast, which again suggests less activity from the NE Caribbean to Bahamas/FL/SE US/E Gulf vs last year’s horrendous season. It suggests near to very slightly below the active 1993-2015 activity in those regions. So, that wouldn’t mean quiet but instead less active than a terrible year. Fingers crossed this will be right, especially for FL/SE US, because another year like 2024 could be a real disaster for especially FL’s home insurance industry. 7/1/25 Euro fcast for August+: 7/1/24 Euro fcast for August+:

BOULDER’S WINDS AREN’T WHAT THEY USED TO BE Extreme gusts in Boulder and Front Range appear to be diminishing JUN 24, 2025 - BY DAVID HOSANSKY Throughout the 1960s, 1970s, and 1980s, wind gusts routinely topped 120 miles per hour (mph), as measured at NSF NCAR’s Mesa Lab in the foothills above southwest Boulder. But the city’s extreme downslope winds have seemingly slackened in the last 30 years, with observed peak gusts rarely approaching 100 mph after 1995. More research is needed to flesh out the reason for the decrease in peak gusts. But the paper suggests it may have to do with changes in atmospheric conditions. As global temperatures have become warmer, tropical storms are pumping more heat high in the atmosphere, affecting upper-level winds in the midlatitudes that could be changing the combination of atmospheric ingredients that produce strong wind gusts during powerful downslope wind events. “The difference in instrument location is part of the story, but the bigger picture probably has to do with changing conditions in the atmosphere,” https://news.ucar.edu/133028/boulders-winds-arent-what-they-used-be —————- Note that the year 1995 was stated as the cutoff point after which extreme gusts started to diminish. The +AMO/current active era/higher ACE for Atlantic tropical activity also started in 1995. Concurrently, the EPAC’s quieter ACE era started in 1995. Coincidence?

VORTEX DATA MESSAGE AL032025 A. 06/01:05:50Z B. 32.45 deg N 078.72 deg W C. 850 mb 1482 m D. 1005 mb E. 015 deg 12 kt F. NA G. NA H. 26 kt I. 212 deg 44 nm 00:51:30Z J. 317 deg 20 kt K. 212 deg 54 nm 00:48:30Z L. 51 kt M. 051 deg 40 nm 01:18:00Z N. 147 deg 55 kt O. 051 deg 42 nm 01:18:30Z P. 17 C / 1519 m Q. 20 C / 1522 m R. 16 C / NA S. 12345 / 8 T. 0.02 / 15 nm U. AF303 0303A CHANTAL OB 03 MAX FL WIND 55 KT 051 / 42 NM 01:18:

Per this in C: -Biggest warmings in 1 yr (per eyeballing) (all >0.2) 1. 2022 to 23 0.30 2. 1976 to 77 0.27 3. 1887 to 88 and 1956 to 57 0.24 5. 1929 to 30 0.21 -Biggest warmings in 2 yr 1. 2022 to 24 0.39 2. 1887 to 89 0.29 3. 2014 to 16 0.28 4. 1971 to 73, 1996 to 98, and 1956 to 58 0.27 7. 1904 to 06 and 1929 to 31 0.26

Last 10 yrs: Subtropical Pac: Subtropical ATL: ATL MDR:

Tropical Storm Chantal Intermediate Advisory Number 4A NWS National Hurricane Center Miami FL AL032025 200 PM EDT Sat Jul 05 2025 ...CHANTAL STRENGTHENS... ...TROPICAL STORM CONDITIONS EXPECTED TO BEGIN IN THE WARNING AREA THIS EVENING... SUMMARY OF 200 PM EDT...1800 UTC...INFORMATION ---------------------------------------------- LOCATION...31.6N 78.7W ABOUT 105 MI...175 KM SE OF CHARLESTON SOUTH CAROLINA ABOUT 185 MI...300 KM SSW OF WILMINGTON NORTH CAROLINA MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H PRESENT MOVEMENT...N OR 360 DEGREES AT 3 MPH...6 KM/H MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES

Peak winds at flight level 46 knots ~100 miles E of center: 151600 3126N 07712W 8423 01602 //// +144 //// 161046

Tropical Storm Chantal Discussion Number 4 NWS National Hurricane Center Miami FL AL032025 1100 AM EDT Sat Jul 05 2025 Satellite images suggest that Chantal has been organizing and gaining strength. The storm is still asymmetric though, with most of the associated showers and thunderstorms located near and to the east of the center. The Air Force Hurricane Hunters are currently investigating the system and have found that the pressure has dropped to 1007 mb. The plane has yet to sample the area of strong thunderstorms, where the highest winds are likely occurring. The initial intensity is set at 35 kt for now. The outer rainbands are beginning to reach portions of South and North Carolina, and conditions along the coast within the watch and warning areas are expected to continue to deteriorate throughout the day. Chantal has barely moved since last night, but a motion to the north-northwest is expected to begin soon. The main steering features appear to be a mid- to upper-level low over the Gulf and a narrow mid-level ridge across the mid-Atlantic region. The flow between these features should cause Chantal to move inland over South Carolina Sunday morning. It should be noted that center reformations are possible, which could cause some erratic motion. After landfall, a turn to the northeast is expected when the storm moves on the western side of the ridge. The NHC track forecast lies close to the previous one, and the latest HCCA and Google Deep Mind solutions. Additional strengthening seems likely in the short term as Chantal is expected to remain over warm water and move into a lower wind shear environment. In addition, the shear direction is expected to shift from southwesterly to southerly, which is more conducive for strengthening. The NHC intensity forecast is a little higher than the previous one, and in line with the latest HMON, HAFS-A, and HAFS-B guidance. After landfall, steady weakening is expected until the system dissipates in 48 to 60 hours. Chantal is expected to remain a lopsided system during the next day or so. Therefore, the strongest winds are anticipated to occur to the right of the landfall location. FORECAST POSITIONS AND MAX WINDS INIT 05/1500Z 31.1N 78.7W 35 KT 40 MPH 12H 06/0000Z 31.8N 79.0W 45 KT 50 MPH 24H 06/1200Z 33.1N 79.3W 45 KT 50 MPH...INLAND 36H 07/0000Z 34.6N 79.2W 30 KT 35 MPH...INLAND 48H 07/1200Z 35.8N 78.0W 30 KT 35 MPH...POST-TROP/INLAND 60H 08/0000Z...DISSIPATED $$ Forecaster Cangialosi/Konarik

...TROPICAL STORM WARNING EXTENDED NORTHWARD IN NORTH CAROLINA... 11:00 AM EDT Sat Jul 05 Location: 31.1°N 78.7°W Moving: N at 1 mph Min pressure: 1007 mb Max sustained: 40 mph

Per recon:

BULLETIN Tropical Depression Three Advisory Number 2 NWS National Hurricane Center Miami FL AL032025 1100 PM EDT Fri Jul 04 2025 ...TROPICAL DEPRESSION FORECAST TO STRENGTHEN ON SATURDAY... SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION ----------------------------------------------- LOCATION...30.6N 78.9W ABOUT 165 MI...260 KM SSE OF CHARLESTON SOUTH CAROLINA ABOUT 255 MI...415 KM SSW OF WILMINGTON NORTH CAROLINA MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H PRESENT MOVEMENT...STATIONARY MINIMUM CENTRAL PRESSURE...1012 MB...29.89 INCHES Tropical Depression Three Discussion Number 2 NWS National Hurricane Center Miami FL AL032025 1100 PM EDT Fri Jul 04 2025 The depression is less organized on satellite imagery this evening, with a seemingly elongated low-level center near or just west of the deep convection. This structure is due to persistent southwesterly shear, with a mid-level circulation apparent east of the low-level center. The current intensity will remain 30 kt, consistent with data from the last Air Force reconnaissance mission and satellite trends. The system has been moving erratically recently, but a longer term motion is basically stationary. A slow north-northwestward motion is anticipated to begin on Saturday as the depression is steered on the northeast side of a developing mid- to upper-level low over the northeastern Gulf. After that time, the system should be steered to the north and northeast with a gradual increase in forward speed along the western periphery of the subtropical ridge. This motion should bring the center near or over the coast of South Carolina Sunday morning. The new NHC track forecast was nudged to the east, consistent with the latest guidance. The global models generally indicate that the current shear should lessen on Saturday, which could allow for some strengthening in combination with the warm waters of the Gulf Stream. There is plenty of dry air aloft, however, which will probably limit significant development, as well as the current disheveled structure. The bulk of the guidance indicates modest strengthening as the system approaches the coast, and the new forecast follows suit, near the latest model consensus. FORECAST POSITIONS AND MAX WINDS INIT 05/0300Z 30.6N 78.9W 30 KT 35 MPH 12H 05/1200Z 30.9N 79.1W 35 KT 40 MPH 24H 06/0000Z 31.7N 79.5W 40 KT 45 MPH 36H 06/1200Z 32.9N 79.8W 35 KT 40 MPH...INLAND 48H 07/0000Z 34.2N 79.6W 30 KT 35 MPH...POST-TROP/REMNT LOW 60H 07/1200Z 35.5N 78.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 08/0000Z...DISSIPATED $$ Forecaster Blake

Despite some including Grok AI insisting there’d need to be WAY more ocean floor vents than have been discovered for underwater seismic activity to significantly affect SSTs, the AGW denying JB today seems to ignore that per the the attached. He says he’s not aware of any possible explanation for the sharp cooling over the last year in much of the Atlantic other than a sharp reduction in mid ocean seismic activity: You Can't Explain this kind of Drop with Man Made forcing Wow. Look at the MDR drop off in Feb. Co2 does not explain that This might tho

A Tropical Storm Watch has been issued from Edisto Beach, South Carolina to Little River Inlet, South Carolina. Tropical Depression Three Discussion Number 1 NWS National Hurricane Center Miami FL AL032025 500 PM EDT Fri Jul 04 2025 The wind circulation associated with the low pressure area east of the coast of north Florida has become stronger, with aircraft and scatterometer data indicating a well-defined circulation with maximum winds near 30 kt and a radius of maximum wind of about 80-90 n mi. The system has also developed persistent convection east and southeast of the center. Based on these developments, advisories are being started on Tropical Depression Three. The cyclone is currently being affected by 20-25 kt of southwesterly shear caused by a mid- to upper-level trough not far to the west. The initial motion is uncertain due to some reformation of the center, with the best estimate of 360/2 kt. During the next 24 h, the cyclone should move slowly north-northwestward on the northeast side of a developing mid- to upper-level low over the northeastern Gulf. After that time, the system should be steered northward with a gradual increase in forward speed. This motion should bring the center near or over the coast of South Carolina Sunday morning. A generally northward motion should then continue until the system dissipates over land. While the guidance generally agrees with this scenario, there is considerable spread in both the forecast direction and speed, with the HWRF being a notable right outlier. The forecast track is in best agreement with the GFS and the HCCA corrected consensus model. The current shear is expected to diminish on Saturday as the upper-level trough moves westward away from the cyclone and the upper-level winds become southerly. However, the upper-level winds are forecast to become convergent, which may limit the amount of convection the system produces. Most of the guidance shows some development as the system approaches the coast, so the intensity forecast calls for modest strengthening to a tropical storm before the cyclone makes landfall. This forecast is a little below the intensity consensus.

They’re going with a TD rather than STD as of the 5 PM/initial advisory: NHC will initiate advisories on Tropical Depression Three, located in the Atlantic Ocean offshore of the southeastern United States, at 500 PM EDT (2100 UTC).

I just saw this, which suggests the NHC may be going with a 30 knot subtropical depression perhaps due to the center being too broad for TD status: AL, 92, 2025070418, , BEST, 0, 309N, 790W, 30, 1012, SD Also, note the 79.0W longitude, which suggests it’s a little E of the 79.5W longitude that the LLC was earlier supposedly near.