B737-700
Flight Crew Air Transport Pilot (ATP)
Fatigue
Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach; Inflight Event / Encounter CFTT / CFIT
Human Factors; Weather
Approaching BWI we were being vectored for the visual 33L. We were left high on the arrival due to a short flight. We were assigned the RAVNN 6 THHMP transition; but we were limited to 16;000 ft due to an MEL for the number 2 IDG (Integrated Drive Generator) so the altitudes were not flown as assigned on the arrival. Weather was dawn with 7SM visibility and some scattered clouds. We were expecting the visual and on a heading direct GRAFE; the FAF. Approximately one to two miles from GRAFE; ATC asked if we would prefer the ILS. We still didn't have the airport in sight so we elected to take the ILS. We briefed it only as a backup to the visual so everything was setup except for minimums. The PF (Pilot Flying) was busy trying to slow when we were cleared immediately for the ILS. Our course had us headed to GRAFE at approximately 2000 ft.  The aircraft intercepted the Localizer over GRAFE and the PF was busy trying to configure and slow. I had stated the aircraft was not descending yet upon crossing and we were at 2000 ft; all the while in VMC conditions but with the airport not in sight. The VNAV showed us about 500 ft high on the path but correcting. I missed the 1000 ft call due to the rushed conditions but caught up and stated one at 800 ft. The PF was still correcting on the glideslope. We had a Pull Up (I think; it was a GPWS warning but I could be wrong on the exact verbal warning) as the PF was still correcting. We went IMC approximately 400 ft AGL and I called approaching minimums at 100 ft above. I had to reference the Approach plate as we didn't have the minimums set. PF had the correct responses and I called minimums and we landed uneventfully although slightly above REF speed. ATC asked us if the shallow layer was an issue when landing and we stated it was at minimums. The first we were told of any cloud layers. As the PM (Pilot Monitoring); I didn't do my duties when I stayed quiet about a go-around. Everything happened so fast and I had no doubt the PF wouldn't get it stabilized; but it was too late in the approach when it did stabilize. Upon the GPWS call an immediate go-around is required and neither one of us called for it.
B737-700 First Officer reported crew received a GPWS warning on an ILS approach to BWI and encountered IMC conditions close to minimums; did not go around but landed.